SEVERE WEATHER / WINTER WEATHER FORECAST SYNOPSIS…ISSUED DEC. 22, 2014…12:10 P.M. EST

ALL forecasts contained on this site,  are based on my analysis and knowledge of various forecast tools, including information contained in NHC products, and are not copies from any other entity.

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Good day everyone!

We have a twofold weather situation over the next 72 hours.  A low developing in the extreme northern GOMEX, along the Gulf Coast states, will be responsible for a risk of severe weather over LA, MS, AL, and portions of the FL. Panhandle.  As this moves northward, it will deepen to sub 990 mb and eventually be centered over the Great Lakes.  I expect this to be over that region in about the next 60 – 66 hours.  We’ll begin with the severe threat first.

The Storm Prediction Center (SPC), Norman, OK. has designated a MARGINAL risk of Severe Thunderstorms for PORTIONS LOWER MS VALLEY…CENTRAL GULF COAST…

SPC DAY 1 CONVECTIVE OUTLOOK

Based on my analysis of severe weather parameters, and the text portion of this outlook, it appears the main threat, at least early on will be damaging thunderstorm winds.  Isolated supercells are probable, however lack of any strong lift should keep the hail threat down substantially.  It is noted however, that closer to late evening / early morning, thermodynamics may come together enough for a slight threat of an isolated tornado over the region.  My severe weather software program has not been too conclusive over the past 2 days, as there was a large outage of model information from NCEP.  The morning output from the NAM model shows the following area most likely for the severe threat today.

F5 DATA NAM MODEL
f5.namsevere.1-4pm

The following is from WeatherCaster.  This is the STP (Significant Tornado Parameter) map, which indicates where the greatest chance for an isolated event may lie.

NAM STP FORECAST

The SPC has designated a SLIGHT risk of Severe Thunderstorms FROM A PORTION OF THE LOWER MS VALLEY INTO THE GULF COASTAL STATES in the Day 2 Convective Outlook

SPC DAY 2 CONVECTIVE OUTLOOK

Based on analysis of the outlook, and severe weather parameters, thermodynamics are forecast to improve as far as severe weather, and a threat of hail and possibly isolated tornadoes could occur tomorrow.  Since the F5DATA Severe Weather software has been not very conclusive, I will address this threat tomorrow as Day 1, and hopefully will have some better graphics as to where the main threat should be.

Te NAM STP map at the moment indicates where the most likely probability for an isolated tornado event could occur.  Of course this will update by morning.

NAM STP 23 DEC. 1800Z

Residents in the risk areas should monitor  NOAA Weather Radio and NWS statements.

The low mentioned previously, will work its way north to over the Great Lakes region.  This will be the last I mention this one, as I will focus mainly on severe weather tomorrow.

Based on model analysis from Global models and regional NAM, precipitation will start out as rain over the Ohio Valley area and Great Lakes, then turn to snow and wintry mix be very early Christmas Eve morning.

The strongest of the winds however will be along the U.S. Eastern Seaboard initially.  As the low deepens and beings to lift out, strong WNW winds will be experienced over the Ohio and TN valley regions  It appears snowfall accumulations will be limited to a portion of the Ohio Valley and the Great Lakes.  Winds of 25 mph may be experienced along the Eastern Seaboard.

GFS FORECAST MODEL OUTPUT 42 HOURS
06zGFS42

69 HOURS
06zGFS69

The following is forecast snowfall accumulations from the GFS

GFS 96 HOUR SNOWFALL ACCUMULATION

The following graphics are all linked to their respective sites.  You may click on them for current information once refreshing this synopsis page.

SPC CONVECTIVE WATCH DISPLAY

SPC MESOSCALE DISCUSSIONS DISPLAY

NWS HAZARDS DISPLAY

INTELLICAST NWS DOPPLER RADAR (SNOW, ICE, RAIN)

Have a blessed day!

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

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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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