[SWODY1] SWODY1

[Severe Weather Outlook Day 1]

ACUS01 KWNS 281239
SWODY1
SPC AC 281237

DAY 1 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
0737 AM CDT FRI JUL 28 2006

VALID 281300Z - 291200Z

...THERE IS A SLGT RISK OF SVR TSTMS THIS AFTERNOON AND EARLY
TONIGHT FROM SERN NY AND ERN PA INTO SRN NEW ENGLAND....

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS MUCH OF NRN WI INTO SRN
UPR MI....

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS MUCH OF WRN AZ....

...SYNOPSIS...

WATER VAPOR IMAGERY SHOWS VERY WELL THE MID/UPPER LEVEL TROUGH
MOVING EWD ACROSS ERN LOWER MI INTO THE MID MS VALLEY. THIS TROUGH
IS EXPECTED TO CONTINUE MOVG EWD ACROSS THE LOWER GREAT LAKES TODAY
AND NEW ENGLAND TONIGHT.  MID LEVEL RIDGING IS ALSO INDICATED ACROSS
THE NRN PLAINS.  THIS WILL RESULT IN WNWLY FLOW ALOFT OVER THE UPPER
GREAT LAKES THAT WILL BRING A WEAK FRONT SEWD INTO NRN WI THIS
AFTERNOON.  MEANWHILE...SUMMERTIME MID/UPPER LEVEL RIDGE WILL BE
OVER THE CENTRAL INTERMOUNTAIN REGION TODAY...BUT ADVANCE INTO THE
CENTRAL PLAINS TONIGHT AS WEAK INVERTED TROUGH MOVES WWD ACROSS
NM/AZ.

...PARTS OF NY AND SRN NEW ENGLAND...

EARLY VISIBLE SATELLITE IMAGES INDICATE PLENTY OF CLOUD COVER EAST
OF MID/UPPER LEVEL TROUGH ACROSS NY STATE INTO PA AND WEST INTO
OHIO.  THIS WILL LIMIT AMOUNT OF INSTABILITY ACROSS NY INTO NEW
ENGLAND...AND 06Z RUN OF THE NAM SUPPORTED THIS NOTION.  00Z RUN OF
THE WRF INDICATED STRONG THUNDERSTORMS ACROSS THIS REGION THIS
AFTERNOON...BUT WAS ALSO MORE UNSTABLE THAN THE NAM.  POOR LAPSE
RATES WERE EVIDENT IN BOTH NAM AND RUC MODELS WITH LOW/MID LEVEL
LAPSE RATES JUST UNDER 6C/KM.  WSWLY LOW LEVEL FLOW OF 30-35 KT
COUPLED WITH WSWLY 50 KT MID LEVEL FLOW PROVIDES SOME SPEED SHEAR
FOR STRONG THUNDERSTORMS AHEAD OF THE ADVANCING TROUGH...BUT LITTLE
IN THE WAY OF DIRECTIONAL SHEAR.  FORECAST SOUNDINGS DO SHOW SOME
STEEPER LAPSE RATES IN THE LOWEST 3KM ABOVE THE SFC INDICATING THAT
STORMS MOVING INTO SERN NY AND SRN NEW ENGLAND WILL HAVE THE
POTENTIAL FOR STRONG WIND GUSTS LATER THIS MORNING AND THIS
AFTERNOON. BUT...GIVEN THE OVERALL LIMITED POTENTIAL WITH MOIST
LAPSE RATES AND LIMITED INSTABILITY...HAVE LOWERED PROBABILITIES
DOWNWARD...AND DIMINISHED SIZE OF SLGT RISK AREA TO SERN NY STATE
AND ERN PA EWD S OF THE NRN MA BORDER.

...PARTS OF NRN AND WRN WI INTO THE U.P. OF MI...

00Z WRF MODELS SHOWS STRONG SIGNALS OF POTENTIAL LINE OF
STRONG/SEVERE THUNDERSTORMS MOVING SEWD ACROSS NWRN...N CENTRAL AND
NERN WI THIS AFTERNOON.  FRONTAL BOUNDARY ACROSS NWRN MN THIS
MORNING WILL TRACK SEWD AS WNWLY FLOW DEVELOPS DUE TO MINOR RIDGING
FARTHER W OVER THE NRN HIGH PLAINS.  THIS BOUNDARY WILL MOVE INTO
AREAS WHERE IT IS POTENTIALLY UNSTABLE WITH CAPES BETWEEN 1000 AND
1500 J/KG AND MID LEVEL LAPSE RATES ARE AROUND 7C/KM.  THUS...SOME
SEVERE THUNDERSTORMS ARE POSSIBLE LATER TODAY AND EARLY TONIGHT
ACROSS NRN WI INTO S CENTRAL UPR MI WITH MAIN THREAT BEING DAMAGING
WINDS.

MODELS INDICATE THE POTENTIAL FOR SOME THUNDERSTORMS LATER TONIGHT
ACROSS IN WEAK WARM ADVECTION REGIME OVER N CENTRAL MN AS SWLY LOW
LEVEL JET DEVELOPS OVER CENTRAL SD INTO W CENTRAL MN.  ISOLATED
STRONG THUNDERSTORMS ARE POSSIBLE IN ASSOCIATION WITH WEAK MCS
DEVELOPING IN EXIT REGION OF LOW LEVEL JET.

...PARTS OF AZ...

WEAK MID/UPPER LEVEL INVERTED TROUGH IS FORECAST TO MOVE WWD FROM
WRN NM THIS MORNING INTO CENTRAL AND WRN SECTIONS OF AZ LATE
TONIGHT. LATEST SURFACE ANALYSIS SHOWS BAND OF MID 60S TO LOW 70 DEW
POINTS ACROSS S CENTRAL AND WRN AZ THIS MORNING.  THE MODELS
DESTABILIZE THE AIR MASS THIS AFTERNOON WHEN MIXED LAYER CAPE
REACHES BETWEEN 1000 AND 1500 J/KG.  WITH LOW LEVEL LAPSE RATES 
AROUND 7C/KM AND DCAPE JUST OVER 1100 J/KG...LOOK LIKE THUNDERSTORM
ACTIVITY WILL CARRY THE POTENTIAL FOR DOWNBURST WINDS THIS AFTERNOON
AND EARLY TONIGHT.

...PARTS OF OK...

SEVERAL WEAK BOUNDARIES REMAIN OVER WRN AND NRN OK INTO SWRN MO IN
RESPONSE TO HIGH-BASED THUNDERSTORM ACTIVITY ON THURSDAY.  DAYTIME
HEATING SHOULD ONCE AGAIN FAVOR AIR MASS TYPE THUNDERSTORMS LATE
THIS AFTERNOON AND EARLY EVENING ACROSS NRN OK INTO SWRN MO AS AIR
MASS WILL BECOME VERY UNSTABLE WITH MLCAPES JUST BELOW 2700 J/KG AND
MID LEVEL LAPSE RATES NEAR 7C/KM.  THUS...MUCH OF THE ACTIVITY
SHOULD REMAIN BELOW SEVERE LEVELS WITH STRONG GUSTY WINDS ARE
POSSIBLE ACROSS AREA.

..MCCARTHY.. 07/28/2006