Hazardous Weather Outlook 12/19/2011

by Mike on Dec.19, 2011, under Forcasts

The next few days will bring snow, rain, tornadoes, and blizzards to areas of plains and Midwest.

Severe Weather Outlook

12z SPC outlook for 12/19/2011

This outlook provides a look at the main area of concern for a tornado setup in the state of Texas.

From outlook

”

...CNTRL AND E TX TODAY/TNGT...
   50+ KT SLY LLJ WILL PERSIST AHEAD OF W TX UPR SYSTEM TODAY AND
   TNGT...MAINTAINING NWD TRANSPORT OF MOISTURE ACROSS THE SRN PLNS AND
   WRN PARTS OF THE LWR MS VLY.  NEITHER SATELLITE NOR SFC DATA SHOW
   PRESENCE OF ESPECIALLY MOISTURE-RICH AIR OVER THE NWRN GULF FOR THE
   LLJ TO TAP.  NEVERTHELESS...THE DATA DO SUGGEST THAT AHEAD OF
   PACIFIC COLD FRONT...SFC DEWPOINTS WILL RISE INTO THE UPR 50S F AS
   FAR N AS THE RED RIVER LATER TODAY.  VALUES IN THE MID TO UPR 60S
   APPEAR LIKELY OVER THE MIDDLE TX GULF CSTL PLN...WITH PW AOA 1.25
   INCHES.

   HEIGHT FALLS/FORCING FOR ASCENT ON LEADING EDGE OF W TX UPR
   VORT...LOW-LVL UPLIFT ALONG ASSOCIATED PACIFIC FRONT...AND WEAK SFC
   HEATING SHOULD FOSTER DEVELOPMENT OF AN ARC OF SFC TO NEAR SFC-BASED
   TSTMS ALONG THE FRONT FROM ERN PARTS OF THE HILL COUNTRY NWD TO N
   CNTRL TX BY MID TO LATE AFTN.  THIS ACTIVITY SHOULD FAIRLY QUICKLY
   EVOLVE INTO A BROKEN LINE AND CONTINUE E ACROSS THE I-35 CORRIDOR BY
   EARLY EVE.  OTHER...PERHAPS MORE DISCRETE STORMS MAY FORM A BIT
   LATER IN THE DAY OR THIS EVE ALONG PRE-FRONTAL CONFLUENCE AXIS OVER
   THE MIDDLE TX GULF CSTL PLN E/NE TO NEAR THE CLL AREA.

   AS THE UPR LOW CROSSES THE SRN PLAINS...A BAND OF 60 TO 80 KT SSW TO
   SWLY 500 MB FLOW WILL OVERSPREAD WARM SECTOR...YIELDING SHEAR/WIND
   PROFILES FAVORABLE FOR SUSTAINED STORMS/SUPERCELLS.  ALTHOUGH THE
   STRONGEST FORCING FOR ASCENT AND SHEAR WILL RESIDE OVER N
   TX...TEMPORAL BACKING OF MID LVL WINDS AND COMPARATIVELY WEAK LOW
   LVL BUOYANCY /SBCAPE AOB 250 J PER KG/ SHOULD LIMIT THE SVR THREATS
   TO LOCALLY DMGG WIND AND PERHAPS AN ISOLD TORNADO FROM LINE SEGMENTS
   CONTAINING EMBEDDED LEWPS/SMALL BOWS.  MORE SUBSTANTIAL SBCAPE /WITH
   VALUES AOA 1000 J PER KG/ IS EXPECTED FARTHER S FROM CNTRL TX ESE TO
   THE MIDDLE TX GULF CST.  WHILE WIND PROFILES IN THIS REGION WILL BE
   WEAKER RELATIVE TO POINTS N...ABSENCE OF TEMPORAL BACKING OF FLOW
   AND PRESENCE OF GREATER INSTABILITY/WEAKER LINEAR FORCING FOR ASCENT
   MAY SUPPORT A COUPLE SUPERCELLS CAPABLE OF TORNADOES...IN ADDITION
   TO DMGG WIND.  SOME OF THIS ACTIVITY MAY REACH THE CST
   TNGT...AFFECTING AREA FROM PSX TO HOU/GLS.

   THE SVR THREAT SHOULD DIMINISH LATER TNGT/EARLY TUE AS UPR LOW
   CONTINUES NE INTO KS AND FORCING/SHEAR WEAKEN OVER SE TX."

Snow OutlookWith the potential for major amounts of moisture to intrude the Central United States, temperatures below freezing and winds in excess of 35mph Blizzard warnings have been posted.

A BLIZZARD WARNING MEANS SEVERE WINTER WEATHER CONDITIONS ARE
EXPECTED OR OCCURRING. FALLING AND BLOWING SNOW WITH STRONG WINDS
AND POOR VISIBILITIES ARE LIKELY. THIS WILL LEAD TO WHITEOUT
CONDITIONS...MAKING TRAVEL EXTREMELY DANGEROUS. DO NOT TRAVEL. IF
YOU MUST...HAVE A WINTER SURVIVAL KIT WITH YOU. IF YOU GET
STRANDED...STAY WITH YOUR VEHICLE.

Map of moisture potential over the next 5 days.