Monday, January 13, 2014

DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 131220
SWODY1
SPC AC 131218

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0618 AM CST MON JAN 13 2014

VALID 131300Z - 141200Z

...NO SVR TSTM AREAS FORECAST...

...SYNOPSIS...

A POSITIVELY TILTED TROUGH FROM HUDSON BAY TO THE SRN HIGH PLAINS
WILL PROGRESS EWD THROUGH THE CNTRL THIRD OF THE NATION IN RESPONSE
TO THE EQUATORWARD TRANSLATION OF MID/UPPER-LEVEL JET STREAKS FROM
WRN CANADA INTO THE NRN/CNTRL HIGH PLAINS...AND SUBSEQUENT HEIGHT
FALLS/TROUGHING OVER THE N-CNTRL STATES. MEANWHILE...A LOW-LATITUDE
VORTICITY MAXIMUM OVER THE LOWER SABINE RIVER VALLEY WILL WEAKEN
SUBSTANTIALLY WHILE EJECTING NEWD WITHIN A CONFLUENT MIDLEVEL FLOW
REGIME PRECEDING THE POSITIVE-TILT TROUGH MENTIONED ABOVE.

IN THE LOW LEVELS...A WEAK SURFACE CYCLONE HAS DEVELOPED OVER SERN
TX EARLY THIS MORNING WITH THIS FEATURE TRACKING GENERALLY EWD
ACROSS THE GULF COAST STATES BEFORE TURNING MORE NEWD INTO THE
SAVANNAH RIVER VALLEY LATE TONIGHT INTO EARLY TUE. ON THE HEELS OF
THIS LOW PRESSURE...A COLD FRONT FROM THE UPPER GREAT LAKES SWWD
THROUGH THE MID MS VALLEY AND OZARK PLATEAU INTO LOWER RIO GRANDE
VALLEY WILL CONCURRENTLY ADVANCE EWD ACROSS THE GULF COAST
STATES.

...CNTRL/ERN GULF COAST...

LATEST SURFACE/BUOY OBSERVATIONS INDICATE THE PRESENCE OF A WARM
FRONT --SEPARATING BOUNDARY LAYER DEWPOINTS IN THE 50S FROM LOW TO
MID 60S-- LIFTING NWD AHEAD OF THE SURFACE LOW THROUGH FAR SERN
TX...TO ALONG THE LA COAST. FORCING FOR ASCENT/DCVA ASSOCIATED WITH
THE LOW-LATITUDE IMPULSE COUPLED WITH POLEWARD MOISTURE FLUX WITHIN
THE ATTENDING WARM-CONVEYOR AIR STREAM HAVE PROMOTED A SHIELD OF
SHOWERS AND TSTMS FROM THE SABINE RIVER VALLEY AND LOWER MS VALLEY
TO OFF THE TX AND LA COASTS. AS OF 12Z...THE MOST INTENSE STORMS
WERE LOCATED APPROXIMATELY 70 MILES S OF LCH WITHIN THE MORE MOIST
AIR MASS TO THE S OF THE WARM FRONT.

EXPECT THE WARM FRONT TO PROGRESS INLAND OVER AT LEAST FAR SERN LA
TODAY...SUGGESTING A RISK FOR SURFACE-BASED OR NEAR-SURFACE-BASED
STORMS ALONG AND SOUTH OF IT/S LOCATION. GIVEN THE TIGHTENING
MIDLEVEL HEIGHT GRADIENT AND RESULTANT INCREASE IN TROPOSPHERIC WIND
SPEEDS AND SHEAR...A LOW-PROBABILITY THREAT FOR DAMAGING WINDS WILL
EXIST WITH EMBEDDED BOWING SEGMENTS.

THE THREAT FOR STRONG TO MARGINALLY SEVERE STORMS MAY EXTEND AS FAR
E AS COASTAL LOCATIONS OF THE FL PENINSULA THIS AFTERNOON INTO
EVENING. BUT GIVEN THE GENERAL WEAKENING OF THE LEAD SHORT-WAVE
TROUGH AND TENDENCY FOR THE TSTMS TO OUTPACE THE NWD ADVANCEMENT OF
THE WARM FRONT...ANY DAMAGING WIND RISK WILL REMAIN LOW AND SHORT IN
DURATION.

..MEAD/GARNER.. 01/13/2014

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