Sunday, December 27, 2015

SPC Dec 27, 2015 0700 UTC Day 2 Convective Outlook

SPC 0700Z Day 2 Outlook
Day 2 Outlook Image
DAY 2 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
1235 AM CST SUN DEC 27 2015

VALID 281200Z - 291200Z

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF ERN MS...MUCH
OF AL...AND INTO THE FL PANHANDLE...

...THERE IS A MRGL RISK OF SVR TSTMS SURROUNDING THE SLIGHT
RISK...AND EXTENDING NWD INTO MUCH OF TN AND VICINITY...

...SUMMARY...
SHOWERS AND THUNDERSTORMS OVER THE CENTRAL GULF COAST STATES AND
INTO THE TENNESSEE VALLEY/SOUTHERN APPALACHIANS MAY POSE THE RISK
FOR ISOLATED DAMAGING WIND GUSTS AND A COUPLE OF TORNADOES DURING
THE DAY ON MONDAY.

...SYNOPSIS...
A DEEP UPPER LOW PROGGED TO LIE INVOF SERN OK/THE ARKLATEX AREA AT
THE BEGINNING OF THE PERIOD WILL MOVE QUICKLY NNEWD THROUGH THE
PERIOD...REACHING THE UPPER GREAT LAKES REGION BY THE END OF THE
PERIOD.  THE EJECTION OF THIS LOW WILL BE ASSISTED BY AN UPPER
TROUGH EXPECTED TO DIG SEWD ACROSS THE WRN U.S. THROUGH THE PERIOD.

AT THE SURFACE...AN OCCLUDED LOW ROUGHLY COINCIDENT IN LOCATION WITH
THE UPPER LOW WILL TRACK SIMILARLY NNEWD THROUGH THE PERIOD.  THE
TRIPLE POINT OF THE LOW IS PROGGED TO SHIFT EWD ACROSS THE MID
SOUTH...AS THE COLD FRONT ADVANCES ACROSS THE GULF COAST STATES
THROUGH THE PERIOD.

...MID SOUTH/CENTRAL GULF COAST STATES...
A BAND OF SHOWERS AND THUNDERSTORMS -- AND LIKELY SOME ONGOING
SEVERE RISK -- SHOULD BE CROSSING THE MS/NERN AR/WRN TN VICINITY AT
THE START OF THE PERIOD.  THE MOIST/WEAKLY UNSTABLE WARM SECTOR
DOWNSTREAM WILL SUPPORT CONTINUATION OF THIS CONVECTIVE BAND...WITH
SHEAR SUPPORTIVE OF OCCASIONAL EMBEDDED/ROTATING STORMS THROUGH THE
DAY.  THIS WILL ALLOW CONTINUATION OF THE RISK FOR ISOLATED DAMAGING
WINDS AND POSSIBLY A COUPLE OF TORNADOES ACROSS PARTS OF ERN MS AND
AL AND INTO THE FL PANHANDLE.

ATTM...DIFFICULTY/UNCERTAINTY PERSISTS WITH RESPECT TO DELINEATING
THE NRN FRINGE OF POSSIBLE TORNADO RISK.  STRONGER FLOW ALOFT WILL
SHIFT GRADUALLY NWD/AWAY FROM THE GULF COAST LATER IN THE DAY AS THE
UPPER SYSTEM MOVES QUICKLY NNEWD TOWARD THE GREAT LAKES.  AS THIS
OCCURS...THE MORE FAVORABLE KINEMATIC ENVIRONMENT WILL BECOME
INCREASINGLY DE-COUPLED FROM SUFFICIENT THERMODYNAMIC SUPPORT. 
SOMEWHERE ACROSS THE NRN MS/NRN AL/TN VICINITY WILL LIKELY PROVE TO
BE A TRANSITION ZONE IN THAT REGARD...WHICH ATTM PRECLUDES MORE
SUBSTANTIAL EXPANSION OF SLIGHT RISK FARTHER NWD INTO THESE AREAS. 
HOWEVER...WITH SHEAR PROFILES EXPECTED TO BE HIGHLY SUPPORTIVE OF
SUPERCELLS -- AND LOW-LEVEL ROTATION -- ACROSS THIS AREA...CLOSE
SCRUTINY WILL BE REQUIRED IN LATER OUTLOOKS WITH RESPECT HOW FAR NWD
CAPE MAY PROVE TO BE MINIMALLY SUFFICIENT TO SUPPORT APPRECIABLE
RISK FOR TORNADOES.

..GOSS.. 12/27/2015

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