WINTER WEATHER DISCUSSION / POSSIBLE CARIBBEAN DEVELOPMENT FORECAST SYNOPSIS…ISSUED DEC. 07, 2016…5:00 P.M. EST

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(T. F. “Storm” Walsh III)

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Good evening everyone!

GFS surface analysis 1000-500 mb thickness map from 12Z, and current NWS Doppler radar indicate patchy light to moderate snow continues over portions of ND, MN, and WI.  Snow should begin to clear out of ND by late Thu. morning, and begin to move out of MN and WI by early Fri. morning, with snow and winter precipitation moving into MI sometime around or shortly after 2-3 a.m. on Thu., with the snow progressing eastward toward NY and PA by Thu. afternoon.  The next low will begin to bring snow and winter precipitation to the Dakotas area by Sat. morning, which will progress eastward across most of the northern Midwest states, then into the Great Lakes/Ohio Valley region, and eventually into the NE/New England area, and extend into a portion of the Northern Piedmont over extreme western portions of VA/NC, and small portions of KY/TN, by day 5 in the forecast period, from 12Z this morning.  As a general rule of thumb, snow begins behind the blue “540” thickness contour, where precipitation is indicated in green.

GFS 1000-500 MB THICKNESS FORECAST
gfs_namer_006_1000_500_thick
gfs_namer_022_1000_500_thick

gfs_namer_050_1000_500_thick

gfs_namer_085_1000_500_thick

GFS AND ECMWF 120 HOUR SNOWFALL ACCUMULATION FORECAST
gfs_tot_snow_conus_21

ecmwf_tsnow_conus_21

Click on the following image for updated Doppler Radar image.
INTELLICAST NWS DOPPLER RADAR LOOP (SNOW, ICE, RAIN)
usa

The coldest air of the season however, is forecast to plunge pretty far south during the next 72 hours, with freezing temperatures reaching into a portion of the FL. Panhandle, and is reflected in the GFS and NAM Station Interpolated Minimum Temperature Forecast.  Temperatures should begin to slowly modify approximately 36 hours after, with warmer temperatures taking shape.

GFS AND NAM 72 HOUR MINIMUM TEMPERATURE FORECAST
gfs-min
nam-min

INTELLICAST FROST/FREEZE MAP
freeze1

NWS HAZARDS AND WARNINGS DISPLAY (CLICK FOR UPDATED MAP AND INFO)
us

Elsewhere, analysis of the global models today still indicates the majority of the models agree on some sort of low pressure developing in the extreme SW Caribbean Sea within the next 96-120 hours, and moving west into Nicaragua.  Given the consistency of the models, I cannot rule this out, however models are agreeing on a weaker low than previously forecast.  Based on my analysis of the GFS wind shear forecast, upper level winds through the period are forecast to now be marginal for development.  The ECMWF Tropical Cyclone Formation Probability forecast indicates a 30% probability of a Tropical Depression between 96-120 hours.

GFS
gfs_mslp_sig_carib_16
gfs_mslp_sig_carib_20

ECMWF
ecmwf_mslp_sig_carib_17

NAVGEMnavg-2016121200-108-lant-troplant-prp-fcst-gentracker

UKMET
ukm2-2016121200-108-lant-troplant-prp-fcst-gentracker

This will be my final synopsis until either Sat. evening, or late Sun. afternoon.

Have a blessed evening!

T. F. “STORM” WALSH III
GMCS, USCG (ret)
METEOROLOGIST / HURRICANE SPECIALIST /SEVERE WEATHER SPECIALIST
MEMBER WEST CENTRAL FLORIDA AMS
CoCoRAHS OBSERVER

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About palmharborforecastcenter

I am a Tropical Forecast meteorologist, providing hurricane forecasts during the Atlantic Hurricane Season. I retired from the U.S. Coast Guard in July of 2001. Meteorology became my passion in high school, and I have continued my educational background in meteorology since 1996, when I undertook the study of Tropical Meteorology. While working toward my degree, I had to unexpectedly withdraw from college due to my oldest sons medical reasons. I do however, meet the educational criteria of the AMS to be recognized as a meteorologist. Studies include, but are not limited to the Navy Aerographers Mate course, Naval METOC meteorology course, Meteorology 2010 Sophomore level course while attending St. Petersburg College, Clearwater, FL., Basic Forecasting course for operational meteorologists from Rapid WX, meteorology institute, a four month meteorological internship, and extensive research on numerous meteorological topics such as the MJO, NAO, satellite imagery interpretation, etc. I have been forecasting Tropical Weather (Tropical Storms and Hurricanes) since 1996, with my main client being three different Coast Guard Commands.
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2 Responses to WINTER WEATHER DISCUSSION / POSSIBLE CARIBBEAN DEVELOPMENT FORECAST SYNOPSIS…ISSUED DEC. 07, 2016…5:00 P.M. EST

  1. originallt says:

    God Bless all of those affected by Dec. 7th, 1941.

  2. dellamom says:

    Thank you, Storm. Winter appears to be coming early to the Deep South this year. Thank you for keeping us posted.

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