SWODY1
SPC AC 261230
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0730 AM CDT WED MAY 26 2010
VALID 261300Z - 271200Z
...THERE IS A SLGT RISK OF SVR TSTMS OVER PARTS OF NORTHERN NEW
ENGLAND...
...THERE IS A SLGT RISK OF SVR TSTMS ALONG THE FRONT RANGE/EAST
SLOPES OF THE ROCKIES FROM NM TO MT...
...SYNOPSIS...
UPPER LEVEL RIDGING WILL AMPLIFY ACROSS THE CENTRAL CONUS WHILE A
STRONG UPPER LEVEL TROUGH REMAINS ANCHORED OVER THE WEST AND
MAINTAINS MODEST DEEP-LAYER SWLY FLOW FROM SRN CA TO THE NRN ROCKIES
AND ADJACENT HIGH PLAINS. IN THE EAST...A BROAD CYCLONIC CIRCULATION
OFF THE SOUTHEAST COAST WILL REMAIN QUASI-STATIONARY WHILE STRONGER
HEIGHT FALLS...ASSOCIATED WITH A DEEP LOW OVER THE NORTH ATLANTIC
EAST OF NEWFOUNDLAND...WILL SPREAD ACROSS NORTHERN NEW ENGLAND.
AT THE SURFACE...WEAK/RESIDUAL FRONTAL ZONE ACROSS THE UPPER MS
VALLEY TRAILS SWD FROM WI/IL THEN SWWD TO NEAR THE OK/KS BORDER AND
THEN NWWD TO SERN CO. NUMEROUS OUTFLOW BOUNDARIES ARE ANALYZED ALONG
AND SOUTH OF THE OLD FRONTAL ZONE...FROM IA/IL TO KS/OK/TX. DRY LINE
IS BACKED WELL WEST INTO THE HIGHER TERRAIN OF NM AND SERN CO.
BACKDOOR COLD FRONT ASSOCIATED WITH THE NORTH ATLANTIC LOW IS
CURRENTLY SITUATED ACROSS ERN QUEBEC AND THE GASPE PENINSULA.
...NEW ENGLAND/NY...
LIFT ASSOCIATED WITH LARGE SCALE HEIGHT FALLS AND BACKDOOR DOOR
FRONT WILL ACT ON AN INCREASINGLY UNSTABLE AIR MASS ACROSS NRN NEW
ENGLAND THIS AFTERNOON. WHILE STRONGEST INSTABILITY IS EXPECTED TO
EXIST WELL AHEAD OF THE FRONTAL FORCING...FROM UPSTATE NEW YORK
SWD...GREATEST CHANCE FOR STORM INITIATION BASED ON MOST MODEL
GUIDANCE APPEARS TO BE OVER MAINE WHERE STRONGER FORCING AND WEAKER
INHIBITION WILL COEXIST AMIDST SBCAPE OF 500-1000 J/KG. WEAK FRONTAL
WAVE DEVELOPING ALONG THE ADVANCING FRONT MAY FURTHER AID STORM
DEVELOPMENT/ORGANIZATION WHILE DEEP-LAYER FLOW/SHEAR STRENGTHENS TO
GREATER THAN 40KT. A FEW FAST-MOVING AND SUSTAINED STORM UPDRAFTS
MOVING SOUTH AT UP TO 40KT COULD PRODUCE LOCALLY DAMAGING WINDS AND
HAIL POSSIBLY AS LARGE AS GOLFBALLS.
CHANCES FOR STRONG/SEVERE STORMS APPEAR TO BE LOWER WITH WWD
EXTENT...ACROSS THE REST OF NRN NEW ENGLAND AND INTO ERN NEW YORK
WHERE FORCING AND SHEAR WILL BE WEAKER. HOWEVER...SUBSTANTIAL
INSTABILITY WILL DEVELOP ACROSS THESE AREAS WITH AN AXIS OF SBCAPE
OF 2000-4000 J/KG FORECAST FROM THE ST. LAWRENCE VALLEY SEWD TO WRN
MA AND NRN CT. FORECAST SOUNDING INDICATE LIMITED INHIBITION BY LATE
AFTERNOON AND ALMOST ANY STORM INITIATING IN THIS AIR MASS WILL HAVE
THE POTENTIAL TO PRODUCE DAMAGING WINDS AND HAIL.
...HIGH PLAINS/NM TO MT...
MID LEVEL SPEED MAX ROTATING THROUGH THE BASE OF LARGER SCALE TROUGH
WILL SPREAD INLAND FROM SRN CA TO THE INTERMOUNTAIN WEST THIS
PERIOD. GRADUAL INCREASE IN THE SWLY MID LEVEL FLOW WILL COINCIDE
WITH DIURNAL AND DIFFERENTIAL HEATING OVER THE FRONT RANGE AND ERN
SLOPES OF THE ROCKIES WITH MOIST LOW LEVEL SELY UPSLOPE FLOW
STRENGTHENING THROUGH THE DAY.
BY 21Z...EXPECT SBCAPE VALUES TO RANGE FROM ABOUT 1000 J/KG OVER
SERN MT TO AROUND 2000 J/KG ACROSS SERN NM. STORMS ARE LIKELY TO
INITIATE ACROSS THIS ENTIRE EXTENSIVE REGION. STRONGER 0-6KM SHEAR
OF 30-40KT IS FORECAST FROM CO TO WY WHERE A FEW TO SEVERAL
SUPERCELLS COULD DEVELOP WITH ATTENDANT THREATS OF HAIL/WIND AND
TORNADOES. INCREASING LARGE SCALE FORCING FOR ASCENT WILL DEVELOP
ACROSS MT WHERE STORMS SPREADING OFF HIGHER TERRAIN MAY BE
MAINTAINED WELL AFTER DARK...DEVELOPING EAST ALONG INSTABILITY
GRADIENT FROM ERN MT INTO ND...IN THE FORM OF AN MCS WITH WIND AND
HAIL.
STORMS FROM SERN CO TO NM WILL ALSO POSE A THREAT OF SEVERE
WIND/HAIL AND PERHAPS A TORNADO BUT WILL EXIST IN SLIGHTLY WEAKER
FLOW/SHEAR...COINCIDENT WITH LARGE SCALE HEIGHT RISES. THIS SUGGESTS
THAT THIS ACTIVITY WILL BE PRIMARILY DIURNAL IN NATURE AND DECAY
WITHIN A COUPLE HOURS AFTER SUNSET.
...TX...
HIGH RESOLUTION/STORM-SCALE GUIDANCE SUPPORTS THE POTENTIAL FOR ONE
OR TWO CLUSTERS OF INTENSE CONVECTION TO DEVELOP WITHIN STRONGLY
UNSTABLE AIR MASS OVER NW TX THIS AFTERNOON. OBSERVATIONAL EVIDENCE
SUGGESTS THIS IS POSSIBILITY WITH A OUTFLOW/FRONT INTERSECTION AND
WEAK MCV ASSOCIATED WITH DECAYING CONVECTION OVER THE PANHANDLE THIS
MORNING. ABOUT 20KT 0-6KM SHEAR MAY PROMOTE SOME MULTICELL
ORGANIZATION WITH STORM MERGERS AND OUTFLOW INTERSECTIONS PROVING TO
BE AREAS WHERE DAMAGING WINDS AND SOME LARGE HAIL COULD OCCUR.
...KS/NEB TO UPPER MS VALLEY...
SIMILAR REGIME TO TX EXISTS NEAR THE RESIDUAL FRONTAL ZONE FROM
KS/NEB TO IL/WI. MCV OVER NEB/KS ATTM MAY PROVIDE THE IMPETUS FOR
MARGINALLY ORGANIZED STORMS...PERHAPS IN CLUSTERS OR BANDS...CAPABLE
OF LOCALLY DAMAGING WINDS AND PERHAPS SOME HAIL. ANOTHER
CONCENTRATED AREA OF DEVELOPMENT IN WEAKLY SHEARED FLOW MAY EVOLVE
ON THE WRN SHORE OF LAKE MI WHERE OLD FRONT WILL MERGE WITH LAKE
BREEZE DURING PERIOD OF PEAK DESTABILIZATION.
...MO/OZARKS TO LOWER MS VALLEY...
VERY MOIST AIR MASS AND POCKETS OF STRONG HEATING WILL CONTRIBUTE TO
SBCAPE OF 1500-2000 J/KG FROM MO TO THE ARKLATEX AND LOWER MS
VALLEY. WEAK INHIBITION WILL LEAD TO AN INCREASE IN PULSE STORMS
THROUGH THE AFTERNOON AND INTO EARLY EVENING WITH A SCATTERING OF
HAIL/WIND EVENTS POSSIBLE.
..CARBIN/ROGERS/GUYER.. 05/26/2010
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-
To unsubscribe from WX-STORM send e-mail to LISTSERV@LISTSERV.ILLINOIS.EDU with
"unsub wx-storm" in the body of your message. For more information write cnovy@cox.net.
No comments:
Post a Comment