[SWODY2] SWODY2

[Severe Weather Outlook - Day 2]

ACUS02 KWNS 270555
SWODY2
SPC AC 270553

DAY 2 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
1253 AM CDT THU JUL 27 2006

VALID 281200Z - 291200Z

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PORTIONS OF NEW ENGLAND
AND THE MID-ATLANTIC REGION...

...SYNOPSIS...
MODELS IN GOOD AGREEMENT AT DIGGING AN UPPER TROUGH OFF THE PAC
COAST ON FRI WITH A WEAKLY AMPLIFIED TROUGH LIFTING THROUGH NEW
ENGLAND AND MID-ATLANTIC REGIONS.  THE MAJORITY OF THE COUNTRY WILL
CONTINUE BENEATH A LARGE UPPER HIGH THAT WILL BUILD E AND N WITH A
CENTER OVER CO BY EARLY SATURDAY.  A COUPLE OF SHORTWAVE TROUGHS
WILL BE OF INTEREST.

AT THE SFC...A SERIES OF WEAK FRONTS THAT HAVE MOVED SWD IN WAKE OF
DISTURBANCES PASSING WELL N OF THE GRTLKS THE PAST COUPLE OF
DAYS...WILL BE SITUATED FROM THE MID-ATLANTIC REGION WWD INTO THE
CORN BELT.  A NEW SYNOPTIC COLD FRONT/PRE-FRONTAL TROUGH WILL BEGIN
TO MOVE SEWD ACROSS THE DAKS AND INTO PARTS OF THE UPPER GRTLKS AND
UPPER MS VLY REGION BY FRI NIGHT.

...NERN STATES SWD TO THE MID ATLANTIC REGION...
THERE WILL LIKELY BE A FAIR AMOUNT OF CONVECTIVE CLOUD DEBRIS ACROSS
PRIMARILY SRN PARTS OF NEW ENGLAND AND THE MID-ATLANTIC REGION EARLY
ON FRI.  THERE IS SOME QUESTION ON HOW THIS WILL AFFECT AIR MASS
DESTABILIZATION FRI AFTN ALONG/AHEAD OF THE
LEE-TROUGH...PARTICULARLY ACROSS SERN PA...MD...DE...NJ AND VA. 
NONETHELESS...EVEN MODEST HEATING WILL CREATE AN UNSTABLE
ENVIRONMENT GIVEN THE RICH BOUNDARY LAYER MOISTURE IN PLACE.  TSTMS
WILL LIKELY DEVELOP ALONG/AHEAD OF THE PRE-FRONTAL TROUGH/MOUNTAINS
FROM PORTIONS OF NEW ENGLAND SWD INTO NERN PA BY EARLY AFTN.  OTHER
STORMS ARE POSSIBLE FARTHER S...THOUGH COVERAGE WILL BE MODULATED BY
INSTABILITY FACTORS.

AS THE UPPER TROUGH BEGINS TO ACCELERATE NEWD...WLY MID-LEVEL FLOW
AOA 30 KTS IS EXPECTED ATOP THE SSWLY LOW-LEVEL FLOW.  ANY TSTM THAT
DEVELOPS IN THIS ENVIRONMENT MAY BECOME ORGANIZED AND PRODUCE MAINLY
DAMAGING WINDS.  MAIN LIMITING FACTORS FOR A ROBUST SEVERE EVENT
WILL BE THE MEAGER MID-LEVEL LAPSE RATES.  ACTIVITY SHOULD MAINLY BE
DIURNALLY DRIVEN AND WEAKEN DURING THE EVE AND/OR AS STORMS MOVE TO
THE MARINE LAYER IN SERN NEW ENGLAND/LONG ISLAND.

...SRN PLATEAU/SWRN DESERTS...
THE HIGH PRECIPITABLE WATER AIR MASS ACROSS THE SWRN DESERTS IS APT
TO BE ADVECTED NWD INTO PARTS OF THE SRN GRT BASIN AHEAD OF THE
DIGGING PAC NW TROUGH ON FRI. THIS MAY SUPPORT A NWD EXPANSION OF
THE ISOLD SEVERE THREAT INTO PARTS OF SRN UT AND SWRN CO.  FARTHER
S...WITH THE EXPECTED INCREASE IN TSTMS OVER AZ AHEAD OF THE
MID-LEVEL IMPULSE ON DAY 1 /THU/...THERE COULD VERY WELL BE A DOWN
DAY ACROSS THE SWRN DESERTS...DESPITE THE ARRIVAL OF AN INVERTED
TROUGH MOVING WWD FROM SRN NM/NRN CHIHUAHUA.  BUT... THESE DETAILS
ARE DIFFICULT TO ANTICIPATE THIS FAR IN ADVANCE.  THUS...WILL
CONTINUE AT LEAST ISOLD SEVERE PROBABILITIES OVER THE ENTIRE REGION.


...NRN MN/UPPER GRTLKS REGION...
LARGE SCALE HEIGHT RISES AND WARMING ALOFT CAN BE EXPECTED OVER THE
MAJORITY OF THE PLAINS ON FRI. THIS SHOULD INHIBIT SFC-BASED TSTM
CHANCES ALONG THE SEWD MOVING COLD FRONT EXPECTED TO MOVE ACROSS THE
ERN DAKS AND MN FRI AFTN/EVE.  BUT...DOWNSTREAM...A WEAKER CAP AND A
WEAK INFLUENCE OF A DISTURBANCE PASSING JUST N OF THE REGION WILL
EXIST ACROSS PORTIONS OF NERN MN...NRN WI AND UPPER MI.  A FEW
SFC-BASED STORMS WILL BE POSSIBLE LATE FRI AFTN/EVE ACROSS THE
REGIONS...LIKELY TRANSITIONING INTO AN ELEVATED STORM CLUSTER FRI
NIGHT. INITIAL ACTIVITY WILL HAVE THE RISKS FOR ISOLD LARGE HAIL
AND DAMAGING WINDS...WITH THE SEVERE THREATS DIMINISHING OVERNIGHT
AND WITH EWD EXTENT.

..RACY.. 07/27/2006