Skip to content

Apr 7, 2014 1300 UTC Day 1 Convective Outlook

April 7, 2014

Apr 7, 2014 1300 UTC Day 1 Convective Outlook

day1otlk

day1probotlk_torn

day1probotlk_wind

day1probotlk_hail

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0746 AM CDT MON APR 07 2014

VALID 071300Z – 081200Z

…THERE IS A SLGT RISK OF SVR TSTMS FROM THE ERN GULF CST NEWD INTO THE MID-ATLANTIC…

…THERE IS A SLGT RISK OF SVR TSTMS OVER PARTS OF THE OH VLY…

…SYNOPSIS…
PROGRESSIVE PATTERN OF RECENT DAYS WILL BECOME MORE AMPLIFIED THIS PERIOD AS W CST RIDGE BUILDS NWD INTO SW CANADA AND NLY JET STREAK ON ITS DOWNSTREAM SIDE AT LEAST TEMPORARILY RETARDS EWD ADVANCE OF MS VLY TROUGH. THE LEAD IMPULSE OF THE LATTER TROUGH…NOW OVER ERN AR…SHOULD CONTINUE NNE INTO KY/WRN OH THIS EVE…AND INTO PA/NY BY 12Z TUE…LEAVING A TRAIL OF VORTICITY EXTENDING SSW TO THE CNTRL GULF CST.

AT LWR LVLS…SFC LOW ATTENDANT TO AR IMPULSE SHOULD TRACK FROM MIDDLE TN THIS MORNING INTO CNTRL OH TNGT…BEFORE CONTINUING NNE TO ERN LK ONT EARLY TUE. AS THIS OCCURS…DIFFUSE COLD FRONT EXTENDING SSW FROM THE LOW SHOULD BECOME BETTER-DEFINED…WITH THE BOUNDARY REACHING THE WRN SLOPES OF THE CNTRL AND SRN APPALACHIANS THIS EVE…AND PIEDMONT PORTIONS OF THE MID AND SOUTH ATLANTIC STATES BY 12Z TUE. SYNOPTIC-SCALE WARM FRONT EXTENDING GENERALLY E FROM THE LOW ALSO SHOULD BECOME BETTER-DEFINED WITH TIME. THE NWD ADVANCE OF THIS BOUNDARY ALONG THE ERN SLOPES OF THE APPALACHIANS WILL…HOWEVER…BE SLOWED AND COMPLICATED BY /1/ COOL SECTOR PRECIPITATION AND /2/ PERPETUATION OF WEDGE-TYPE AIR MASS OVER WRN PORTIONS OF NC…VA….AND MD.

CONTINUED INFLOW OF MOISTURE-RICH AIR AHEAD OF COLD FRONT AMIDST AMPLE DEEP SHEAR FOR SUSTAINED STORMS/SUPERCELLS WILL YIELD A FAIRLY BROAD CORRIDOR WITH AN APPRECIABLE RISK FOR DMGG WINDS AND TORNADOES FROM THE ERN GULF CST REGION NE TO THE MID ATLANTIC CST. A MORE CONDITIONAL SVR WEATHER THREAT WILL EXIST CLOSER TO THE UPR TROUGH OVER PARTS OF THE OH VLY.

…ERN GULF CST NEWD TO THE MID-ATLANTIC TODAY/TNGT…
AMPLIFICATION OF LARGE-SCALE TROUGH OVER THE CNTRL U.S. WILL BE ACCOMPANIED BY FURTHER STRENGTHENING OF MODERATELY STRONG DEEP SWLY FLOW ALREADY IN PLACE FROM THE CNTRL AND ERN GULF CST NEWD ACROSS THE SRN AND CNTRL APPALACHIANS TO THE MID-ATLANTIC STATES. BY THIS EVE…A BROAD SWATH OF 500 MB FLOW WITH SPEEDS IN EXCESS OF 60 KTS SHOULD EXTEND FROM THE FL PANHANDLE THROUGH THE CAROLINAS TO PA….WITH SPEEDS LIKELY TO INCREASE TO AOA 80 KTS EARLY MON. COUPLED WITH A SUSTAINED INFLUX OF APPRECIABLE MOISTURE /PW AROUND 1.75 INCHES/…SETUP APPEARS FAVORABLE FOR CONTINUED RE-DEVELOPMENT AND NEWD EXPANSION OF EXISTING PRE-FRONTAL CONVECTION NOW OVER THE ERN GULF CST REGION AND GA.

WHILE MID-LVL LAPSE RATES WILL REMAIN WEAK…DIURNAL HEATING SHOULD SUPPORT MODEST STRENGTHENING OF ONGOING BROKEN PRE-FRONTAL SQLN NOW OVER SRN AL AND THE WRN FL PANHANDLE AS THAT SYSTEM CONTINUES STEADILY EWD INTO GA. WIND PROFILES AND THERMODYNAMIC ENVIRONMENT SUGGEST A CONTINUED POTENTIAL FOR OCCASIONAL EMBEDDED SUPERCELLS/BOWING SEGMENTS WITH A RISK FOR DMGG WIND AND OCCASIONAL TORNADOES. WITH LEAD /AR/ SHORTWAVE IMPULSE MOVING NEWD INTO THE OH VLY…LARGE-SCALE ASCENT ACROSS THE SOUTHEAST U.S. WILL REMAIN MODEST…WITH WEAK HEIGHT FALLS TIED LARGELY TO AMPLIFICATION OF LARGER-SCALE TROUGH IN THE PLNS. NEVERTHELESS…GIVEN QUALITY OF MOISTURE RETURN…AND THE LIKELIHOOD FOR MORE SUBSTANTIAL HEIGHT FALLS LATER IN THE PERIOD AS THE PLNS TROUGH CONTINUES EWD…SOME SVR THREAT COULD LINGER INTO TNGT AND EARLY TUE AS THE STORMS MOVE/DEVELOP E TO THE ERN GA/NRN FL CSTL PLN.

FARTHER N…SVR THREAT IS EXPECTED TO BE CONFINED TO AREAS ALONG AND E OF SW-NE ORIENTED WEDGE BOUNDARY HUGGING THE ERN SLOPES OF THE SRN AND CNTRL APPALACHIANS. WITH SSWLY 850 MB FLOW ALREADY IN PLACE OVER THE SC AND NC PIEDMONT AND CSTL PLN EXPECTED TO INCREASE TO AOA 50 KTS LATER TODAY…AND TO ABOVE 60 KTS TNGT… IT SEEMS REASONABLE TO EXPECT THAT TSTMS WILL DEVELOP NEWD FROM GA ALONG AND E OF THE WEDGE BOUNDARY LATER TODAY THROUGH TNGT…ESPECIALLY GIVEN WEAKLY-CAPPED THERMAL PROFILE OF 12Z CHS RAOB. THE STORMS MAY MOVE/DEVELOP NEWD INTO TIDEWATER VA AND ERN MD EARLY TUE AS LOW-LVL DESTABILIZATION SPREADS NEWD. STRENGTH OF LOW TO MID-LVL SHEAR AND INCREASING MOISTURE SUGGEST A POTENTIAL FOR EMBEDDED SMALL SUPERCELLS AND/OR BOWS…WITH AN ATTENDANT RISK FOR DMGG WIND AND TORNADOES.

…MID/UPR OH VLY THIS AFTN/EVE…
SUBSTANTIAL DCVA WILL SPREAD NE ACROSS KY AND NRN TN THIS AFTN…AND INTO THE UPR OH VLY THIS EVE…ON LEADING EDGE OF AR UPR IMPULSE. THE ASCENT WILL BE ACCOMPANIED BY VERY STRONG DEEP SHEAR…WITH 500 MB SW WIND SPEEDS INCREASING TO AROUND 100 KTS. SATELLITE DATA SUGGEST THAT SOME SFC HEATING SHOULD OCCUR OVER KY-TN AS UPR-LVL CLOUD SHIELD ASSOCIATED WITH STORMS OVER THE SERN U.S. CONTINUES NEWD. BOUNDARY LAYER MOISTURE WILL REMAIN COMPARATIVELY LIMITED…WITH DEWPOINTS AROUND 50 F AND PW AROUND 1 INCH. BUT COUPLED WITH EVEN MODEST HEATING…COOL 500 MB TEMPERATURES /MINUS MID-TEENS DEG C/ COULD YIELD ABOUT 500 J/KG MUCAPE.

WITH SFC LOW EXPECTED TO DEEPEN AS THE AR VORT CONTINUES NEWD…TRAILING COLD FRONT SHOULD BECOME BETTER-DEFINED WITH TIME AND SERVE AS A FOCUS FOR LOW-LVL UPLIFT. COUPLED WITH THE LIKELY THERMODYNAMIC AND WIND ENVIRONMENT…SETUP COULD SUPPORT A BAND OF STORMS POSING A RISK FOR DMGG WIND…MARGINALLY SVR HAIL…AND POSSIBLY A COUPLE TORNADOES THROUGH EARLY EVE.

…CNTRL/SRN PLNS THIS AFTN/EVE…
MODEST SFC-BASED INSTABILITY /MLCAPE OF 250-750 J PER KG/ WILL DEVELOP WITH SFC HEATING OVER THE CNTRL AND SRN PLNS TODAY IN ZONE OF DEEP CYCLONIC FLOW BENEATH AMPLIFYING UPR TROUGH. WEAK LOW-LVL WIND SHIFT AXES ACCOMPANYING THIS AMPLIFICATION SHOULD BE THE FOCUS FOR SCTD DIURNALLY-ENHANCED CONVECTION OVER A LARGE SWATH OF THE CNTRL AND SRN PLNS. THIS ACTIVITY SHOULD…HOWEVER…BE MOST CONCENTRATED FROM CNTRL AND ERN KS SWD INTO MUCH OF WRN AND CNTRL TX…WHERE FEW PULSE CELLS COULD YIELD MARGINALLY SVR WIND AND PERHAPS AN INSTANCE OR TWO OF MARGINALLY SVR HAIL.

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: