Skip to content

Feb 18, 2014 0830 UTC Day 3 Severe Thunderstorm Outlook

February 18, 2014

Feb 18, 2014 0830 UTC Day 3 Severe Thunderstorm Outlook

day3otlk

day3prob

DAY 3 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0229 AM CST TUE FEB 18 2014

VALID 201200Z – 211200Z

…THERE IS A SLGT RISK OF SVR TSTMS FROM ROUGHLY THE MS VALLEY REGION EWD TO THE APPALACHIANS…AND FROM SRN PORTIONS OF THE GREAT LAKES SWD TO THE GULF COAST…

…SYNOPSIS…
LARGE-SCALE UPPER TROUGHING IS FORECAST TO CONTINUE EXPANDING ACROSS THE CENTRAL U.S. WITH TIME…WITH THE ENTIRE U.S. UNDER THE INFLUENCE OF CYCLONIC FLOW ALOFT BY THE END OF THE PERIOD. THIS EXPANSION OF LONG-WAVE TROUGHING WILL OCCUR DUE TO THE INTERACTION OF TWO SMALLER-SCALE TROUGHS — ONE ADVANCING EWD AND THEN NEWD ACROSS THE CENTRAL U.S. WHILE A SECOND DIGS SEWD OUT OF WRN CANADA INTO THE NRN ROCKIES THROUGH THE END OF THE PERIOD. THE INITIAL/CENTRAL U.S. TROUGH — A VERY INTENSE FEATURE PROGGED TO TAKE ON A NEGATIVE TILT AS IT CROSSES THE MID AND UPPER MS/OH VALLEYS THROUGH THE SECOND HALF OF THE PERIOD — WILL BE THE PRIMARY FEATURE OF INTEREST WITH RESPECT TO SEVERE CONVECTION THIS PERIOD.

AS THIS SYSTEM ADVANCES/STRENGTHENS…A SURFACE LOW — PROGGED INITIALLY TO LIE INVOF THE KS/MO BORDER AREA — IS FORECAST TO SHIFT RAPIDLY NNEWD AND DEEPEN SUBSTANTIALLY WITH TIME…REACHING THE UPPER GREAT LAKES REGION AS A SUB-980 MB CYCLONE BY MIDNIGHT. MEANWHILE…A STRONG/TRAILING COLD FRONT SHOULD EXTEND FROM ROUGHLY LK MI SSWWD ACROSS THE LOWER OH/TN/LOWER MS VALLEYS INTO THE WRN GULF COASTAL REGION BY SUNSET. THE FRONT WILL THEN CONTINUE RACING EWD ACROSS THE GREAT LAKES/OH VALLEY/MID SOUTH/CENTRAL GULF COASTAL REGION OVERNIGHT…AND IS PROGGED TO LIE IN LEE OF THE APPALACHIANS BY THE END OF THE PERIOD. BY MID TO LATE AFTERNOON…THE FRONT SHOULD DRIVE DEVELOPMENT OF A LINE OF ORGANIZED/FAST-MOVING THUNDERSTORMS BRINGING A RISK FOR SEVERE WEATHER — MAINLY IN THE FORM OF WIDESPREAD DAMAGING WIND GUSTS — TO AN AREA FROM ROUGHLY THE MS VALLEY TO THE APPALACHIANS.

…IL/ERN MO/ERN AR/LA EWD TO THE APPALACHIANS…
CONVECTION IS PROGGED TO BE ONGOING AT THE START OF THE PERIOD ACROSS PARTS OF ERN KS/MO AND EWD INTO THE OH VALLEY…WITHIN A ZONE OF WARM ADVECTION WITHIN THE NE QUADRANT OF THE SURFACE LOW. BY MID AFTERNOON…SURFACE COLD-FRONTAL ADVANCE INTO A MOISTENING/DESTABILIZING WARM SECTOR SHOULD YIELD CONVECTIVE DEVELOPMENT IN THE ZONE OF STRONG/LINEAR LOW-LEVEL ASCENT…WITH STORMS THEN EXPANDING BOTH NE AND SW ALONG THE ADVANCING BOUNDARY. GIVEN THE STRONG DEEP-LAYER WIND FIELD ACCOMPANYING THIS SYSTEM DRIVING FAST LINE MOTION…RISK FOR NUMEROUS DAMAGING GUSTS IS APPARENT. ISOLATED TORNADOES WILL ALSO BE POSSIBLE WITHIN THE LINE…WHILE ISOLATED/MARGINAL HAIL MAY ALSO OCCUR — MAINLY NEAR AND S OF THE OH VALLEY WHERE A MORE UNSTABLE ENVIRONMENT IS EXPECTED.

OVERNIGHT…STORMS WILL ADVANCE RAPIDLY EWD ACROSS THE OH/TN VALLEYS AND CENTRAL GULF COAST STATES…WITH ACCOMPANYING SEVERE RISK EXTENDING EWD TO THE CENTRAL AND SERN APPALACHIANS THROUGH THE END OF THE PERIOD.

Advertisements

From → Weather Blog

Leave a Comment

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s

%d bloggers like this: