Weather December 3, 2020
25 responses | 0 likes
Started by metmike - Dec. 3, 2020, 7:39 p.m.

Delightful December to you!

 

December 9: The AO/NAO really drop today. This is significant enough to have more confidence that the models are not cold enough yet. Typically, what we see in a solidly -AO/-NAO pattern is that models continue to get colder and colder(more HDD's) with each update as they get a better handle of the pattern which is predicted by the -AO-NAO. This is exactly whats happened the last couple of days.

December 6 update: Most models keep the frigid air locked up in Canada, which means very mild in the US.  AO/NAO has an extremely wide range in solutions. As long as some hang on to the solidly negative AO/NAO(minority) there is still a chance(waning) that it could turn sharply colder. The Canadian model has turned milder, towards the the very mild GFS. 


December 5 update:

AO and NAO dropped a bit more but the spread and disparity in model solutions is massive

and the difference that it will make to temperatures later in December is stratospheric.

Canadian model is potentially very cold(with its cold bias). European model is shifting in that direction. The GFS disagrees strongly and is very mild.

I'll update the products below this weekend.

+++++++++++++++++++++++++++++++++++++++

December 4 update: AO/NAO are dropping lower today, staying below 0 and reintroducing more risk of the frigid air in Canada getting transported south(that was taken out on Thursday when the AO/NAO shifted higher), although most 2 week solutions are not showing that.............yet. Great uncertainty!


 Cross polar flow in week 2 will fill Canada up with FRIGID air. Fairly zonal flow in the US on models keeps most of it locked up to our north............for now. This mild December outlook has crushed NG prices the last 2 days.

Very poor agreement on some features in week 2 makes the forecast uncertain and small shifts with a huge temperature gradient will count for big temperature changes for some places.


Reasons to keep being thankful here in 2020!

https://www.marketforum.com/forum/topic/45623/



NEW: Detailed analysis. Latest COVID-19 numbers. Hospitals are near capacity in many places.

https://www.marketforum.com/forum/topic/61206/


 Scroll down and  enjoy the latest comprehensive weather to the max...... occurring because of the natural physical laws in our atmosphere as life on this greening planet continues to enjoy the best weather/climate in at least 1,000 years(the last time that it was this warm) with the added bonus of extra beneficial CO2.

Most maps below will automatically update each day(not the snow map).


Total Snowfall the next 2 weeks. Not much for December(except for New England)!


Weather Model


 

Go to the link below, then hit the location/county on the map for details.

                 https://www.spc.noaa.gov/                 Go to "hazards"      


Here are the latest hazards across the country.

                                                            Southern Florida NE Gulf N of 25N E of 87WGulf from 22N to 25N E of 87W including Straits of Florida NW Gulf including Stetson BankN Central Gulf including Flower Garden Banks Marine SanctuaryW Central Gulf from 22N to 26N W of 94WCentral Gulf from 22N to 26N between 87W and 94W Atlantic from 27N to 31N W of 77WAtlantic from 27N to 31N between 70W and 77WAtlantic from 27N to 31N between 65W and 70WBahamas N of 22N including the Cay Sal BankAtlantic from 22N to 27N E of Bahamas to 70W Tropical N Atlantic from 15N to 19N between 55W and 60WCaribbean N of 18N between 76W and 85W including the Cayman BasinCaribbean N of 18N between 76W and 85W including the Cayman BasinCaribbean approaches to the Windward PassageAtlantic S of 22N W of 70W including approaches to the Windward PassageNewport/Morehead City, NCBrownsville, TXCorpus Christi, TXHouston/Galveston, TXNew Orleans, LALake Charles, LAMobile, ALTallahassee, FLTampa, FLMiami, FLKey West, FLFlorida KeysMiami, FLMelbourne, FLJacksonville, FLCharleston, SCWilmington, NCBaltimore/Washington, DCWakefield, VAPhiladelphia/Mt. Holly, PA/NJNew York, NYBoston, MAGray/Portland, ME Intra Coastal Waters from Schoodic Point ME to Stonington MECoastal Waters from Schoodic Point ME to Stonington ME out 25 NMWaters from Eastport ME to Stonington ME from 25 to 40 NMNortheast Minnesota and Northern WisconsinNorthern MichiganNorthern MichiganNorthern MichiganEast Central Wisconsin - Green BayEast Central Wisconsin - Green BaySouthern and Southeastern WisconsinNortheastern Illinois and Northwestern Indiana - ChicagoNorthern Indiana and Northwestern OhioSouthwestern MichiganNortheast Michigan - GaylordNortheast Michigan - GaylordNortheast Michigan - GaylordSoutheastern Michigan - DetroitSoutheastern Michigan - DetroitSoutheastern Michigan - DetroitNorthern OhioWestern New York - BuffaloWestern New York - Buffalo Northern MichiganLos Angeles, CASan Diego, CASan Francisco Bay Area/Monterey, CAEureka, CAMedford, ORPortland, ORSeattle, WALos Angeles AreaLos Angeles AreaLos Angeles AreaLos Angeles AreaLos Angeles AreaLos Angeles AreaSouth Central CaliforniaSan Francisco AreaWestern NevadaNorth Central CaliforniaNorthwest California CoastSouthwest Oregon and Northern CaliforniaNortheast Oregon and Southeast WashingtonNorthwest OregonNorthwest WashingtonEastern Washington and Northern IdahoSouthern Nevada, Southeastern California and Northwestern Arizona - Las VegasSouthwestern California - San DiegoCentral Arizona and California DesertsSoutheast ArizonaNorthern ArizonaUtahNorthern and Northeastern NevadaSouthwestern Idaho and Eastern OregonSoutheastern IdahoWestern Montana and Central IdahoCentral Montana - Great FallsNortheastern MontanaSoutheastern MontanaWestern WyomingSoutheastern Wyoming and Western NebraskaNortheastern ColoradoWestern Colorado and Eastern UtahSoutheastern ColoradoNorthern and Central New MexicoSouthern New Mexico and extreme Western Texas - El PasoTexas and OklahomaLubbock and South Plains TexasWestern Texas and Southeastern New MexicoWestern South Dakota and Northeastern WyomingNorthwestern Kansas and East Central Colorado - GoodlandCentral Nebraska - North PlatteNorth Central Kansas and South Central NebraskaSoutheastern South Dakota, Southwestern Minnesota, and Northwestern IowaNorthern and Northeastern South DakotaWestern North DakotaEastern Nebraska and Southwestern Iowa - Omaha ValleyNortheastern KansasSoutheastern KansasSouthwestern Kansas - Dodge CityCentral OklahomaEastern Oklahoma and Northwestern ArkansasDallas and Fort WorthCentral Texas - San AngeloAustin and San Antonio TexasCorpus Christi, Victoria, and Laredo TexasSouthern TexasTexas - Houston/GalvestonSoutheast Texas and Southwest LouisianaNorthern Louisiana and Eastern Texas - ShreveportArkansasSouthwestern MissouriNorthwestern MissouriCentral IowaSouthern MinnesotaNortheastern North Dakota and Northwestern MinnesotaNortheast Minnesota and Northern WisconsinSouthwestern Wisconsin, Southeastern Minnesota, and Northeast IowaEastern Iowa and Northwestern Illinois - Quad CitiesEastern Missouri - West Central IllinoisWestern Tennessee, Eastern Arkansas and Northern Mississippi - MemphisCentral MississippiSoutheastern LouisianaMiddle TennesseeNorthern AlabamaCentral AlabamaMobile - PensacolaWest Central FloridaEast Central FloridaPanhandle of Florida and Southwestern GeorgiaNortheast Florida and Southeast GeorgiaNorthern and Central GeorgiaLow Country of South Carolina and GeorgiaNortheastern South Carolina and Southeastern North Carolina - WilmingtonCentral South Carolina and CSRAWestern North Carolina and Northwest South CarolinaEastern TennesseeEastern KentuckyCentral KentuckySouthern Illinois and Indiana, Southeastern Missouri and Western KentuckyCentral and East Central IllinoisCentral IndianaNortheastern Illinois and Northwestern Indiana - ChicagoSouthern and Southeastern WisconsinEast Central Wisconsin - Green BayNorthern MichiganNortheast Michigan - GaylordNortheast Michigan - GaylordSoutheastern Michigan - DetroitSouthwestern MichiganNorthern Indiana and Northwestern OhioSouthwestern Ohio Northern KentuckyWest VirginiaWestern Virginia, Southeast West Virginia, and Northwest North CarolinaCentral North Carolina - RaleighEastern North CarolinaEastern Virginia, Southern Maryland and Northeast North CarolinaWashington D.C., Central Maryland, Northern Virginia, Eastern West VirginiaWestern Pennsylvania, East Central Ohio and Extreme Western MarylandNorthern OhioCentral PennsylvaniaNew Jersey, Delaware, and Southeastern PennsylvaniaNew York City and Surrounding AreasSouth Central New York and Northeastern PennsylvaniaWestern New York - BuffaloEastern New York and Western New England AreasBoston and Surrounding AreasNorthern Vermont and New YorkSouthern Maine and New HampshireNorthern Maine Gulf of Maine to the Hague LineGeorges Bank between Cape Cod and 68W north of 1000 fathomsSouth of New England between the Great South Channel and Montauk Point to 1000 fathomsSouth of Long Island between Montauk Point and Sandy Hook to 1000 fathomsHudson Canyon to Baltimore Canyon to 1000 fathomsBaltimore Canyon to Cape Charles Light to 100 NM offshoreCape Charles Light to Currituck Beach Light to 100 NM offshoreCurrituck Beach Light to Cape Hatteras to 100 NM offshoreCape Hatteras to Cape Fear to 100 NM offshoreCape Fear to 31N to 1000 FMGeorges Bank between 68W and the Hague LineEast of 69W to the Hague Line between 1000 fathoms and 39NEast of 69W and south of 39N to 250 NM offshoreBetween 1000 fathoms and 38.5N west of 69WBaltimore Canyon to 69W east of 1000 fathoms and south of 38.5N to 250 NM offshoreBaltimore Canyon to Hatteras Canyon between 100 NM and 250 NM offshoreHatteras Canyon to Cape Fear 100 NM and 250 NM offshoreCape Fear to 31N east of 1000 fathoms to 250 NM offshoreCape Flattery to Cape Shoalwater between 60 NM and 150 NM offshoreCape Shoalwater to Cape Lookout between 60 NM and 150 NM offshoreCape Lookout to Florence, OR between 60 NM and 150 NM offshoreFlorence, OR to Point St. George between 60 NM and 150 NM offshorePoint St. George to Point Arena between 60 NM and 150 NM offshorePoint Arena to Pigeon Point between 60 NM and 150 NM offshorePigeon Point to Point Piedras Blancas between 60 NM and 150 NM offshorePoint Piedras Blancas to Santa Cruz Island, CA between 60 NM and 150 NM offshoreSanta Cruz Island, CA to San Clemente Island, CA between 60 NM and 150 NM offshoreCape Flattery to Cape Shoalwater between 150 NM and 250 NM offshoreCape Shoalwater to Cape Lookout between 150 NM and 250 NM offshoreCape Lookout to Florence, OR between 150 NM and 250 NM offshoreFlorence, OR to Point St. George between 150 NM and 250 NM offshorePoint St. George to Point Arena between 150 NM and 250 NM offshorePoint Arena to Pigeon Point between 150 NM and 250 NM offshorePigeon Point to Point Piedras Blancas between 150 NM and 250 NM offshorePoint Piedras Blancas to Santa Cruz Island, CA between 150 NM and 250 NM offshoreSanta Cruz Island, CA to 120W between 150 NM and 250 NM offshoreSan Clemente Island, CA to Guadalupe Island from 60 NM Offshore west to 120W                                                                                                                                                                  


Purple/Pink/blue on land is cold/Winter weather. Brown is wind,  Green is flooding. Gray is fog.  Reddish is a red flag advisory.  

Go to the link below, then hit the location/county on the map for details.

                 https://www.spc.noaa.gov/                 Go to "hazards"                                                                                     

                   



 

https://www.mesonet.org/index.php/weather/map/us_air_temperature/air_temperature


https://www.mesonet.org/index.php/weather/map/wind_chill_heat_index1/air_temperature



 Current Weather Map


NCEP Days 0-7 Forecast Loop
NCEP Short-Range Model Discussion
NCEP Day 3-7 Discussion

 

       
Understanding These Maps
Surface Map Legend
Precip Legend
NCEP Surface Maps
(Mouseover)

U.S. Surface Analysis
National Radar Image
12-Hr Forecast
24-Hr Forecast
36-Hr Forecast
48-Hr Forecast
Short Term Loop
Day 3 Forecast
Day 4 Forecast
Day 5 Forecast
Day 6 Forecast
Day 7 Forecast
Low Tracks Error Circle
Low Tracks Ensemble





Legend

                                        

                          


Current Jet Stream


Low Temperatures Tomorrow Morning

                    

                    

                    


                                        

Highs today and tomorrow.

 

                                    

Comments
By metmike - Dec. 3, 2020, 7:41 p.m.
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Highs for days 3-7:

A bit chilly..............but it's December!

Warming up next week though!


http://www.wpc.ncep.noaa.gov/medr/DAY3_MAX_filled.gif

https://www.wpc.ncep.noaa.gov/medr/DAY4_MAX_filled.gif

http://www.wpc.ncep.noaa.gov/medr/DAY5_MAX_filled.gifhttp://www.wpc.ncep.noaa.gov/medr/DAY6_MAX_filled.gif

                                    

https://www.wpc.ncep.noaa.gov/medr/DAY7_MAX_filled.gif

                                    

By metmike - Dec. 3, 2020, 7:42 p.m.
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Lows days 3-7 below:

Freeze line fairly far south but not  unusual for this time of year!

Warming up next week.


https://www.wpc.ncep.noaa.gov/medr/medr_min.shtml

https://www.wpc.ncep.noaa.gov/medr/DAY3_MIN_filled.gifhttps://www.wpc.ncep.noaa.gov/medr/DAY4_MIN_filled.gifhttps://www.wpc.ncep.noaa.gov/medr/DAY5_MIN_filled.gifhttps://www.wpc.ncep.noaa.gov/medr/DAY6_MIN_filled.gifhttps://www.wpc.ncep.noaa.gov/medr/DAY7_MIN_filled.gif

                                    

                                    


By metmike - Dec. 3, 2020, 7:42 p.m.
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Temperatures compared to Average for days 3-7

Above average N.Plains.  Chilly in the Deep South vs average.


https://www.wpc.ncep.noaa.gov/medr/medr_mean.shtml


https://www.wpc.ncep.noaa.gov/medr/DAY3-7_MAX_ANOM_filled.gif


https://www.wpc.ncep.noaa.gov/medr/DAY3-7_MIN_ANOM_filled.gif


By metmike - Dec. 3, 2020, 7:44 p.m.
Like Reply

Surface Weather features days 0-1-2 then days 3-7:


 Pretty quiet. No major snow. 


https://www.cpc.ncep.noaa.gov/products/forecasts/

Days 0-1-2 below:


Forecast of Fronts/Pressure and Weather valid Sun 18Z


Forecast of Fronts/Pressure and Weather valid Mon 12Z

Forecast of Fronts/Pressure valid Tue 12Z



Days 3-7 below:
https://www.wpc.ncep.noaa.gov/medr/5dayfcst_wbg_conus.gif


                                    

                                    


            

                

By metmike - Dec. 3, 2020, 7:46 p.m.
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Total Snowfall the next 2 weeks. Not much for December(except for New England)!


Weather Model


By metmike - Dec. 3, 2020, 7:48 p.m.
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Liquid equivalent precip forecasts for the next 7 days are below.


Mostly Dry!


Day 1 below


http://www.wpc.ncep.noaa.gov/qpf/fill_94qwbg.gif?1526306199054

http://www.wpc.ncep.noaa.gov/qpf/fill_94qwbg.gif?1531339983148

Day 2 below:

http://www.wpc.ncep.noaa.gov/qpf/fill_98qwbg.gif?1528293750112


http://www.wpc.ncep.noaa.gov/qpf/fill_98qwbg.gif?1531340045174


Day 3 below

http://www.wpc.ncep.noaa.gov/qpf/fill_99qwbg.gif?1528293842764

http://www.wpc.ncep.noaa.gov/qpf/fill_99qwbg.gif?1531340092706



Days 4-5 below:

http://www.wpc.ncep.noaa.gov/qpf/95ep48iwbg_fill.gif?1526306162

http://www.wpc.ncep.noaa.gov/qpf/95ep48iwbg_fill.gif?1531339379

 Days 6-7 below:

http://www.wpc.ncep.noaa.gov/qpf/97ep48iwbg_fill.gif?1526306162

http://www.wpc.ncep.noaa.gov/qpf/97ep48iwbg_fill.gif?1531339379

7 Day Total precipitation below:

https://www.wpc.ncep.noaa.gov/qpf/p168i.gif?1566925971


https://www.wpc.ncep.noaa.gov/qpf/p168i.gif?1566925971

  

                                    


                                    

By metmike - Dec. 3, 2020, 7:48 p.m.
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Excessive rain potential.

None


Mesoscale Precipitation Discussions

  

Current Day 1 ForecastCurrent Day 1 Excessive Rainfall Forecast

 

Day 1 Threat Area in Text Format  


  Day 2 and Day 3 Forecasts 
Current Day 2 ForecastCurrent Day 2 Excessive Rainfall Forecast


Day 2 Threat Area in Text Format 

 

Current Day 3 ForecastCurrent Day 3 Excessive Rainfall Forecast

                                    

By metmike - Dec. 3, 2020, 7:49 p.m.
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Severe Storm Risk the next 8 days:

Quiet!!

https://www.spc.noaa.gov/


Current Day 1 Outlook
        1300 UTC Day 1 Outlook             
               
          Current Day 2 Outlook
          0600 UTC Day 2 Outlook               
         
          Current Day 3 Outlook
          0600 UTC Day 3 Outlook               
                F
          Current Day 4-8 Outlook
          Day 4-8 Convective Outlook

           

                                    


            

                

By metmike - Dec. 3, 2020, 7:50 p.m.
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Current Dew Points


Dry air in place. Gulf of Mexico closed for water vapor transport business to the north.

Current Dew Points

                                    

Latest radar loops


http://www.nws.noaa.gov/radar_tab.php

Doppler Radar National Mosaic Loop

                       


 

Upper Mississippi Valley sector loop

  


 (3400x1700 pixels - 2.2mb)
Go to: Most Recent Image

      

Central Great Lakes sector loop
Go to: Most Recent Image

                                  

    You can go to this link to see precipitation totals from recent time periods:


https://water.weather.gov/precip/


                              Go to precipitation, then scroll down to pick a time frame. Hit states to get the borders to see locations better. Under products, you can hit "observed" or "Percent of Normal"

                                    

                    

                                                                                    

            

                            

Soilmoisture anomaly:


These maps sometimes take a day to catch up to incorporate the latest data(the bottom map is only updated once a week).



https://www.cpc.ncep.noaa.gov/products/Soilmst_Monitoring/US/Soilmst/Soilmst.shtml#

                            

Daily Soil Moisture Pecentile       

        Daily Anomaly Soil Moisture (mm)

        Monthly Soil Moisture Change

https://www.cpc.ncep.noaa.gov/products/analysis_monitoring/regional_monitoring/palmer.gif


By metmike - Dec. 3, 2020, 7:52 p.m.
Like Reply

Drought Monitor maps:

Latest: The first map below is the latest. The 2nd one is from last week.


April 23: LOOKY_LOOKY!  For the first time this year, its gotten dry enough for a few (small)areas in the Upper Midwest/Western Cornbelt to report slight drought.

April 30: Drought increased a bit......Plains and U.Midwest.

May: 7:  Drought increased a bit from KS westward.

May 14: Drought increased a bit again, now, parts of Iowa have slight drought(this dry weather is why planting is ahead of schedule). Rains are coming to the dry spots in the forecast though.......bearish.

May 21:  A bit more drought in ND.

May 28: Not much change

June 4: Drought increases a tad in the N.Plains and Upper Midwest.

June 10: Drought worsening in the S.Plains could be part of the La Nina signal!!

June 17: Drought got worse again in the S.Plains and yellows/slight drought emerged in new locations............all of Indiana.

June 24: Drought help in some places(KS) but increased a bit in others(ND).

July 1: Drought shrunk in Ohio Valley(I got 5.5 inches of rain in sw INdiana!) but not much change elsewhere. Surprised it didn't shrink more in IN/IL where some places(Bowyer) got great rains recently.

July 8: The main change was an increase over w.IA and e.NE. At the end of July with the hot/dry weather coming up, the S.Plains drought should expand into the S.Midwest to the Eastern Cornbelt.

July 15: Drought increased again over IA/MO/IN/OH. In july, evaporation usually exceeds rainfall, so some of this is seasonal. Hot temps coming up will accelerate evaporation.

July 22: Some Recent rains in IN did not make the cutoff.

July 29: Main dry spots are W.Iowa and IN/OH. Upcoming rains prospects good for ECB.

August 6: Drought got much worse in Iowa.

August 13: Looks like rains on Monday made no difference to W.IA drought(only around 1 inch).

August 20: IA is very dry.........into N.IL now.

August 27: Drought got worse in IA!!

September 3:  Drought worse in IA and IL, N.IN!

September 10: We should probably be noting the real drought out West. The Rockies back to OR is the most severe.

October 1: La Nina driven severe drought out West, some of which has pushed into the Plains and even parts of the Midwest in recent months.

Oct. 7: Drought intensifies..............which is not unusual since this is the driest time of year seasonally.

November 5: Drought improves in the S.Plains!

November 12: Not much change. Hard to increase drought at this time of year with the cooler temperatures.

November 19: Drought worsens a bit out West!

November 26: Drought worsens more out West!

December 3: Drought worsens more out West! It's the La Nina!

      https://droughtmonitor.unl.edu/     

             

  Drought Monitor for conus

Drought Monitor for conus

By metmike - Dec. 3, 2020, 7:59 p.m.
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The top map is the Canadian ensemble average,  the maps below are the individual members that make up the average at the end of week 2.

+++++++++++++++++++++++++++++++++++++++++

Each member is like the parent, Canadian model operational model.......with a slight tweek/variation in parameters. Since we know the equations to represent the physics of the atmosphere in the models are not perfect, its useful to vary some of the equations that are uncertain(can make a difference) to see if it effects the outcome and how.

The average of all these variations(ensembles) often yields a better tool for forecasting. It's always more consistent. The individual operational model, like each individual ensemble member can vary greatly from run to run.........and represent an extreme end of the spectrum at times. The ensemble average of all the members, because it averages the extremes.............from opposite ends of the spectrum.........changes much less from run to run.

End of week 2....................0z  Canadian ensembles:

November 24: The mean below looks pretty zonal and benign but thats because it averages out alot of high amplitude solutions that cancel out the extremes with the majority NOT looking like the average/mean below. That means high uncertainty. Several  individual solutions are very cold in the Midwest/East.  Others are pretty mild. With the AO and NAO dropping in week 2, I am in the colder camp for now. The European Ensemble strongly favors this too.

November 25/26:  Same as previous discussion. Massive disparities on location of upper level low in Canada, location of all the large scale features and position of the jet stream. The ensemble average does show a modest ridge/west-trough/east couplet which would mean chilly air east but some solutions are VERY amplified with the average of all solutions dampening that out.

November 30: Deep upper level low, somewhere in Canada. Temps will be frigid close to it. The farther south it is, with troughing underneath, the colder it is in the US. The farther north that it is, the more zonal the flow is in the US beneath it which would cut off the cold. Huge disparity in solutions. Upper level ridging in the Southwest looks La Nina-ish with dry/warm there.

December 3: The Deep upper level low in Canada IS the Polar Vortex. The position, in Central to Northern Canada with mostly zonal flow underneath it, keeps the frigid air locked up in Canada. Cross polar flow into Canada fills it with bitter cold in week 2 but most of it stays to our north with these solutions. The pattern needs to amplify, with more ridging in the West to force any major cold southward, downstream into the US.

372h GZ 500 forecast valid on Dec 19, 2020 00 UTC

GZ 500 forecastGZ 500 forecastGZ 500 forecastGZ 500 forecast

Forecasts for the control (GEM 0) and the 20 ensemble members (global model not available)

By metmike - Dec. 3, 2020, 8:04 p.m.
Like Reply

Individual GFS ensemble solutions for the latest 12z run at 360 hours:

http://mp1.met.psu.edu/~fxg1/ENSHGT_0z/f384.gif


November 26: Position of upper level low in Canada varies a great deal. It's the location of this feature that will determine how deeply the REAL cold is able to penetrate in the East.  Some solutions have this feature in N.Canada and cut off the major cold far to the north..............and are very mild with zonal flow. Others are VERY cold with a deep upper level low close to the US border. A dropping AO/NAO favors the colder solutions but the AO/NAO are also products of the same models and can be wrong too.

November 30: Potential ridge west, trough east/downstream couplet. Too many variations to have any confidence in any solution but this is leaning a bit to cooler conditions. 

December 3: Polar Vortex/Upper Level Low in Canada is all over the place on this model. The majority of  solutions keep it or pieces of it too far north to threaten the US with the frigid air that will be in place across much of Canada in week 2 because of cross polar flow(on several solutions). Not complete agreement though and enough variation to create high uncertainty but overall, right now this is a mild solution for much of the US in mid December.


http://www.meteo.psu.edu/fxg1/ENSHGT_0z/f360.gif


By metmike - Dec. 3, 2020, 8:12 p.m.
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GFS Ensemble mean(average of all the individual solutions above).  The first map is a mid/upper level map. The 2nd one is a temperatures map at around 1 mile above the surface. These are anomalies(difference compared to average).

NCEP Ensemble t = 360 hour forecast


December 3: Transient pattern?  Positive anomaly in the Plains/Midwest means mild temps at 168 hours. At 360 hours, we see a great deal of changing. Negative anomaly in West/Central Canada and potential cross polar flow brings high confidence of frigid weather in Canada. Modest positive anomalies south of that in the US and mostly zonal flow suggests very mild temps in the US. With bitter cold in Canada within striking distance and amplification or buckling of the flow from zonal, west to east to more meridional, north to south would cause the currently mild mid December outlook to shift markedly colder.

https://www.psl.noaa.gov//map/images/ens/z500anom_f168_nhbg.gif



https://www.psl.noaa.gov//map/images/ens/t850anom_f168_nhbg.gif



2 weeks out below

NCEP Ensemble t = 360 hour forecast product


                                   

https://www.esrl.noaa.gov/psd/map/images/ens/t850anom_f360_nhbg.gif

                                    ++++++++++

By metmike - Dec. 3, 2020, 8:17 p.m.
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Latest, updated graph/forecast for AO and NAO and PNA here, including an explanation of how to interpret them...............mainly where they stand at the end of 2 weeks


https://www.marketforum.com/forum/t


Previous analysis, with the latest day at the bottom for late week 2 period.

Discussions, starting with the oldest  below.

November 26:  Some pretty extreme values recently.  +++AO and ++NAO.  This has been a factor in the mild weather recently. Both plunge to -AO/-NAO at the end of 2 weeks. Which is usually a COLD pattern and potentially very cold if it amplifies. A -AO/-NAO is favorable for transporting air from high latitudes to mid latitudes. Impressive ++PNA drops to +PNA. This is a HUGE factor with the upcoming  cold being able to penetrate deeply south.

November 30: AO/NAO plunge from the recent strong positives to negative  which favors a pattern change to colder but at the end of the period the spread is pretty wide and gives us great uncertainty. The solidly positive PNA drops close to 0 by the end of 2 weeks.

December 3: Recent +AO/+NAO that caused a mild November will drop negative but unlike the forecast from several days ago, it bounces back to zero,  instead of staying negative, which will reduce chances for the frigid air in Canada to be flushed from high latitudes to the mid latitudes in mid December. The recently impressive ++PNA will drop to zero and also result in less push of  cold air into the southlands.

By metmike - Dec. 3, 2020, 8:18 p.m.
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National Weather Service 6-10 day, 8-14 day outlooks.

 Updated daily just after 2pm Central.


Temperature Probability


6 to 10 Day Outlook - Temperature Probability Precipitation Probability


  6 to 10 Day Outlook - Precipitation Probability


  


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Temperature Probability

8 to 14 Day Outlook - Temperature Probability
8 to 14 Day Outlook - Precipitation Probability

           

                                    


                                    


By metmike - Dec. 3, 2020, 8:22 p.m.
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The week 3 and week 4 CFS model  really warmed up yesterday across the entire country.........near record warmth?

Bone chilling cold in Canada from cross polar flow in week 3 though. If the polar vortex associated with this cold shifts south or the AO/NAO drop more negative, then this cold will have an opportunity to plunge into the US......but not under the currently predicted scenario.


https://www.cpc.ncep.noaa.gov/products/people/mchen/CFSv2FCST/weekly/images/wk3.wk4_latest.NAsfcT.png

                                    


By metmike - Dec. 4, 2020, 1:33 p.m.
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December 4 update: AO/NAO are dropping lower today, staying below 0 and reintroducing more risk of the frigid air in Canada getting transported south(that was taken out on Thursday when the AO/NAO shifted higher), although most 2 week solutions are not showing that.............yet. Great uncertainty!

By metmike - Dec. 5, 2020, 11:16 a.m.
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December 5 update:

AO and NAO dropped a bit more but the spread and disparity in model solutions is massive

and the difference that it will make to temperatures later in December is stratospheric.

Canadian model is potentially very cold(with its cold bias). European model is shifting in that direction. The GFS disagrees strongly and is very mild.

I'll update the products above this weekend.

By metmike - Dec. 6, 2020, 3:28 p.m.
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December 6 update: Most models keep the frigid air locked up in Canada, which means very mild in the US.  AO/NAO has an extremely wide range in solutions. As long as some hang on to the solidly negative AO/NAO(minority) there is still a chance(waning) that it could turn sharply colder. The Canadian model has turned milder, towards the the very mild GFS. 

By Jim_M - Dec. 6, 2020, 9:09 p.m.
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Jan NG heading to $2

By metmike - Dec. 7, 2020, 1:19 a.m.
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And the way ng trades, it might get there this week (-:

By metmike - Dec. 7, 2020, 11:51 a.m.
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December 7: There won't be much cold with anomalies like this:

NCEP Ensemble t = 360 hour forecast product


                                   NCEP Ensemble t = 360 hour forecast product 


            

                

By metmike - Dec. 8, 2020, 12:22 p.m.
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metmike: Models, especially the GFS products look very mild in week 2 with the frigid air locked up in Canada(high confidence that Canada will fill up with frigid air later this month).

HOWEVER, as long as the AO and NAO are predicted to be negative in week 2, there is a legit threat that the models are underestimating the amount of cold headed towards the US. Superimposing  a -AO/-NAO on to model solutions in week 2 make them colder and increase chances of them turning colder.

Tuesday 12z update: The cold biased Canadian model has turned sharply colder because of several solutions that shift the polar vortex a couple thousand miles farther east than the other ones and where the GFS ensembles has it.  This actually is possible in a -NAO/-AO regime, so I won't rule it out.

By metmike - Dec. 9, 2020, 1:19 a.m.
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European Ensembles also came in colder early Tue afternoon.

By metmike - Dec. 9, 2020, 11:49 a.m.
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December 9: The AO/NAO really drop today. This is significant enough to have more confidence that the models are not cold enough yet. Typically, what we see in a solidly -AO/-NAO pattern is that models continue to get colder and colder(more HDD's) with each update as they get a better handle of the pattern which is predicted by the -AO-NAO. This is exactly whats happened the last couple of days.