Saturday, May 15, 2010

DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 150600
SWODY1
SPC AC 150559

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1259 AM CDT SAT MAY 15 2010

VALID 151200Z - 161200Z

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PORTIONS OF SW TX...

...THERE IS A SLGT RISK OF SVR TSTMS OVER THE MID-SOUTH/TN VLY...

...SYNOPSIS...
PERSISTENT UPR TROUGH ACROSS THE WRN STATES WILL GRADUALLY BEGIN
MOVING INTO THE PLAINS SATURDAY AND SATURDAY NIGHT. AHEAD OF THE
SYSTEM...A LEAD SHORTWAVE TROUGH/MULTIPLE MCVS WILL CONTINUE ENE
FROM PARTS OF E TX/AR TOWARD THE LWR OH VLY DURING THE AFTN.
UPSTREAM...ANOTHER IMPULSE SHOULD TRAVEL FROM ALONG THE AZ/SONORA
BORDER TO THE SRN HIGH PLAINS BY LATE AFTN.

IN THE LWR LVLS...THE CDFNT FOLLOWING A DEPARTING UPR WAVE FROM THE
NERN COAST WILL SETTLE SWD INTO NC AND TN...BUT BEGIN RETURNING NWD
ACROSS AR AND TX AHEAD OF THE APPROACHING LARGER SCALE WRN STATES
TROUGH.

...SRN HIGH PLAINS AND SW TX...
TSTMS HAVE QUICKLY DEVELOPED IN WAKE OF THE LATE FRIDAY EVE MCS...
PROBABLY IN RESPONSE TO THE APPROACHING JETLET OVER SRN AZ. THIS
WILL LIKELY MAINTAIN A CONVECTIVELY-ENHANCED OUTFLOW/COOLER BOUNDARY
LAYER OVER SW TX THROUGH FRI AFTN. MORNING ACTIVITY SHOULD CONTINUE
ENE AND GRADUALLY WEAKEN AWAY FROM THE STEEPER LAPSE RATE
ENVIRONMENT DURING THE MIDDAY HOURS.

ADDITIONAL STORMS ARE EXPECTED TO FORM OVER THE HIGHER TERRAIN OF
SRN CO...NM AND SW TX DURING PEAK HEATING. STRONGEST
INSTABILITY/HEATING WILL EVOLVE IN SE NM AND SW TX AND AS WEAK
HEIGHT FALLS CONTINUE THROUGH THE AFTN ALONG THE BASE OF THE WRN
TROUGH...STORMS WILL MATURE INTO SUPERCELLS WITH LARGE HAIL AMIDST
DEEP LAYER SHEAR OF 35-40 KTS. ACTIVITY WILL PROBABLY DEVELOP INTO
AN MCS...PROGRESSING ESE INTO A WEAK SELY LLJ/LLVL THETA-E AXIS
TOWARD THE SRN/ERN EDWARDS PLATEAU DURING THE EVENING. SPORADIC
LARGE HAIL AND HIGH WINDS CAN BE EXPECTED THROUGH LATE EVENING
BEFORE WEAKENING.

FARTHER N...THE ISOLD STORMS THAT DEVELOP OVER NM/SRN CO IN
COMPARATIVELY WEAKER INSTABILITY WILL STILL POSE AN ISOLD LARGE
HAIL/GUSTY WIND THREAT. HERE...MID-LVL TEMPERATURES WILL FALL INTO
THE MID-MINUS TEENS WITH MRGL SHEAR PROFILES TO SUPPORT BRIEF STORM
ORGANIZATION. THIS ACTIVITY WILL EVENTUALLY DEVELOP ENE INTO THE TX
PNHDL AND OK THROUGH EARLY MORNING SUNDAY.

...MID-SOUTH/TN VLY...
NOCTURNAL TSTMS ASSOCD WITH APPARENT MULTIPLE MCVS SHOULD BE ONGOING
FROM PARTS OF ERN AR AND NRN LA AT THE START OF THE PD. THESE
FEATURES SHOULD BEGIN MOVING ENE TOWARD THE MID-SOUTH SATURDAY
MORNING WITH ATTENDANT SSWLY 35-40 KTS OF MID-LVL FLOW. DOWNSTREAM
AIR MASS SHOULD BEGIN TO RECOVER AND HEAT SUFFICIENTLY TO SUPPORT
TSTM DEVELOPMENT ALONG ERN PERIPHERY OF CLOUD/PCPN CANOPY FROM PARTS
OF NRN MS INTO THE LWR OH VLY BY AFTN. THERE SHOULD BE MRGLLY
SUPPORTIVE THERMODYNAMIC/KINEMATIC PROFILES FOR BRIEF SUPERCELL
ORGANIZATION...BUT MOST LIKELY MULTICELL CLUSTERS CAPABLE OF DMGG
WINDS...HAIL AND PERHAPS A BRIEF TORNADO. THESE THREATS WILL EXTEND
TO SCNTRL KY AND MIDDLE TN DURING THE LATE AFTN/EARLY EVE WITH A
GRADUAL DECREASE IN SVR THREATS.

...NC...
REGION WILL EXPERIENCE SLIGHT LARGE SCALE RIDGING IN WAKE OF THE
DEPARTING NERN TROUGH BY SATURDAY AFTN. NONETHELESS...THE AIR MASS
WILL BECOME UNSTABLE OWING TO HEATING AND MID 60S DEW POINTS BENEATH
MODEST MID-TROPOSPHERIC LAPSE RATES ALONG/S OF THE STALLING FRONT.
WEAK CONVERGENCE INVOF THE FRONT WILL PROBABLY CONTRIBUTE TO WDLY
SCTD TSTMS DURING PEAK HEATING. DESPITE THE STORMS DEVELOPING IN
ONLY 30 KTS OF 0-6KM SHEAR...FCST SOUNDINGS DO SUGGEST POTENTIAL FOR
ISOLD DMGG WIND GUSTS WITH THE STRONGER MULTICELL STORMS.

..RACY/ROGERS.. 05/15/2010

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