Wednesday, May 16, 2012

DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 161235
SWODY1
SPC AC 161233

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0733 AM CDT WED MAY 16 2012

VALID 161300Z - 171200Z

...THERE IS A SLGT RISK OF SVR TSTMS NERN PA...CNTRL/ERN AND UPSTATE
NY...WRN NEW ENGLAND...

...SYNOPSIS...
A NEGATIVELY TILTED HUDSON BAY TROUGH WILL ROTATE INTO THE
NORTHEAST...WITH THE ATTENDANT SURFACE COLD FRONT QUICKLY
PROGRESSING OFFSHORE OVERNIGHT.

FARTHER S...A WEAK UPPER DISTURBANCE OVER THE WRN GULF WILL DRIFT
SEWD...MAINTAINING WEAK SWLY FLOW ACROSS THE SOUTHEAST.

TO THE W...A COMPACT UPPER LOW OVER THE SRN GREAT BASIN WILL MEANDER
INTO THE FOUR CORNERS REGION.

...NERN PA...CNTRL/ERN AND UPSTATE NY...WRN NEW ENGLAND...
THE LEADING EDGE OF A STRONG VORT MAX OVER THE GREAT LAKES REGION IS
EXPECTED TO REACH THE NY/PA BORDER AROUND 17-18Z. STRONG FORCING FOR
ASCENT WILL SUPPORT CONVECTIVE INITIATION ALONG THE COLD FRONT OVER
WRN NY/PA. THESE STORMS ARE EXPECTED TO INTENSIFY AS THEY PROGRESS
EWD. AMPLE SURFACE HEATING WILL QUICKLY ERODE WEAK CONVECTIVE
INHIBITION...WITH VERY STEEP LOW LEVEL LAPSE RATES CONTRIBUTING TO A
DMGG WIND THREAT. HOWEVER...WEAK LOW-LEVEL FLOW WILL OCCUR IN
CONJUNCTION WITH THE INITIAL CONVECTIVE DEVELOPMENT...WITH THE
STRONGEST LOW LEVEL FLOW EXPECTED TO BE PRIMARILY POST-FRONTAL. THIS
MAY SOMEWHAT TEMPER A MORE SIGNIFICANT WIND THREAT ACROSS THE
REGION. SEASONABLY COOL TEMPERATURES ALOFT AND STRENGTHENING
DEEP-LAYER SWLYS WILL MORE LIKELY BE SUPPORTIVE OF LARGE HAIL AS
WARM SECTOR DESTABILIZATION OCCURS.

SOMEWHAT PROBLEMATIC IS THE THICK LOW CLOUDS OBSERVED THIS MORNING
OVER ERN NY AND MUCH OF NEW ENGLAND. ALTHOUGH THIS LAYER WILL
GRADUALLY PROGRESS EWD...BOUNDARY LAYER DESTABILIZATION MAY BE
DELAYED ACROSS THESE AREAS. IT IS POSSIBLE THAT A ZONE OF
DIFFERENTIAL HEATING COULD PROVIDE FOCUS FOR A FEW SEVERE STORMS TO
DEVELOP IN ADVANCE OF THE FRONT. IF STORMS CAN OCCUR INDEPENDENTLY
FROM THE FRONT...INCREASING DEEP-LAYER SHEAR MAY SUPPORT WEAK
SUPERCELLS CAPABLE OF DMGG WINDS AND HAIL.

LATER IN THE AFTERNOON...MORE WELL DEVELOPED SMALL BOWING SEGMENTS
AND TRANSIENT SUPERCELLS WILL PROGRESS INTO NEW ENGLAND...WITH A
GREATER THREAT OF LARGE HAIL AND A FEW DMGG GUSTS. NOCTURNAL COOLING
AND WEAKER INSTABILITY INTO MAINE WILL QUICKLY TEMPER THE THREAT
OVERNIGHT.

...ERN CAROLINAS...
DIURNALLY DRIVEN SEA BREEZE STORMS WILL ONCE AGAIN FORM THIS
AFTERNOON. MODERATE SURFACE-BASED INSTABILITY AND STEEPENING
LOW-LEVEL LAPSE RATES SHOULD BE SUFFICIENT FOR A FEW STRONG TO
SEVERE STORMS CAPABLE OF DMGG WINDS. HOWEVER...WEAK HEIGHT RISES AND
RELATIVELY LIGHT LOW LEVEL WINDS WILL LIKELY LIMIT MORE ORGANIZED
POTENTIAL. SEASONABLY COOL TEMPERATURES ALOFT MAY SUPPORT HAIL
FORMATION WITH THE STRONGER CORES. FARTHER S ACROSS SERN GA AND
FL...06Z DETERMINISTIC MODELS ARE NOT DEPICTING A CLUSTER OF
THUNDERSTORMS PROGRESSING INTO THE FL PANHANDLE THIS MORNING VERY
WELL. CLOUD COVER AND RAINFALL FROM THIS INITIAL CONVECTION MAY
LIMIT POTENTIAL DESTABILIZATION.

..HURLBUT/THOMPSON.. 05/16/2012

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