MODERATE SEVERE WEATHER RISK / SPECIAL TROPICAL WEATHER FORECAST SYNOPSIS…ISSUED MAR. 26, 2017…10:10 A.M. EDT

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(T. F. “Storm” Walsh III)

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Good day everyone!

The Storm Prediction Center (SPC) has issued the following risk areas in the day 1 outlook as of the 1300Z update:

…THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS SOUTH-CENTRAL OK AND FAR NORTH-CENTRAL TX…

…THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS CENTRAL/EAST OK INTO FAR NORTH TX…

…THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FAR SOUTH KS…WEST AR…AND NORTH-CENTRAL TX…

…THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS PARTS OF KS/MO/AR/OK/TX…

…THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS UPPER OH VALLEY…

…SPC SUMMARY…
Numerous severe storms with very large hail, tornadoes, and damaging winds are expected after 4 pm CDT across central and eastern Oklahoma into northeast Texas through this evening.

SPC DAY 1 CONVECTIVE OUTLOOK MAPS:

TORNADO PROBABILITY

DAMAGING WIND PROBABILITY
Probability of damaging thunderstorm winds or wind gusts of 50 knots or higher within 25 miles of a point.
Hatched Area: 10% or greater probability of wind gusts 65 knots or greater within 25 miles of a point. 

HAIL PROBABILITY
Probability of one inch diameter hail or larger within 25 miles of a point.
Hatched Area: 10% or greater probability of two inch diameter hail or larger within 25 miles of a point.

Based on information contained in the SPC outlook, as per my analysis, the RAP model seems to have the best handle currently on current forecast soundings.  I am also including the NAM-WRF, given that the model runs differ in forecast time by at least a couple of hours.  Based on analysis of the forecast soundings, modeling suggests the best probability for severe hail, damaging thunderstorm gusts, and some tornadoes lies within the outlined areas, initiating after 4:00 p.m. into early evening.  Forecast sounding data indicates some isolated tornadoes could be strong.  You’ll notice the dryline on the maps.  The severe activity should remain east of the dryline.  It appears that daytime heating, and forcing for ascent may be enough to “break the cap” IVO the dryline later this afternoon, hence the late afternoon initiation.  I based the outlines on the current forecast dewpoints, humidity, SBCAPE, MLCAPE, STP, EHI, SHOWALTER, and Vorticity values.

Residents within the MODERATE and ENHANCED risk areas should closely monitor the situation throughout the day, and monitor NOAA Weather Radio, local news stations, and local NWS Statements and/or warnings.

F5 DATA RAP MODEL SOLUTION

F5 DATA NAM-WRF SOLUTION

IF A TORNADO WARNING IS ISSUED FOR YOUR AREA, TAKE SHELTER IMMEDIATELY!

SPC SITE LINK

SPC CONVECTIVE WATCH DISPLAY

SPC MESOSCALE DISCUSSIONS DISPLAY

NWS DOPPLER RADAR SITE MAP

INTELLICAST RADAR SUMMARY

NWS HAZARDS AND WARNINGS DISPLAY (click on graphic, then your area of interest)

Elsewhere, and area of low pressure continues to develop, north of Hispaniola.

NOAA CARIBBEAN SATELLITE LOOP IMAGERY

RAMSDIS TROPICAL VIS/IR IMAGERY

Models are in fair agreement of a surface low eventually closing off, and lowering of pressures is noted in the normalized anomaly maps, with the system becoming a 1006-1003 mb closed low within 36-48 hours.

Currently, upper level winds are not really conducive for full development or tropical development, and the forecast indicates wind shear to remain hostile during the next 2-3 days.  However, the current area is situated to the east of the trof axis, which is allowing for some minimal evacuation over a small portion of this system.  At the moment, SST’s are warm enough over the area for sub-tropical support, albeit I believe the probability for this is slim, as drier air is noted moving SE toward the area in MIMIC TPW loop imagery, even though the NCEP EMC Cyclogenesis indicates about a 90% probability of tropical development.  The current Cyclone Phase Evolution data does show some discrepancies, in that the GFS shows this remaining slightly warm core through the period, with the CMC turning it asymmetric cold core in 72 hours.

NCEP EMC CYCLOGENESIS PROBABILITY

MIMIC TPW LOOP

Current and forecast steering layers maps indicate this low is being blocked by a ridge to its north, and the area is nearly stationary, to slow NNW movement at the moment.  Forecast steering indicates this motion to continue for at least the next 24 hours.  Thereafter, the ridge to the north collapses, and the steering flow will begin to move this to the NE to ENE, away from the U.S. and any land masses.

I have to work tomorrow, but intend to have an update on both severe weather and this area of interest in the W. Atlantic.

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

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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 MODERATE SEVERE WEATHER RISK / SPECIAL TROPICAL WEATHER FORECAST SYNOPSIS…ISSUED MAR. 26, 2017…10:10 A.M. EDT

  1. originallt says:

    Thanks, Storm. Saw that Sun. night there was some huge hail in N. Texas and Oklahoma.

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