SWODY2
SPC AC 101710
DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1210 PM CDT SAT APR 10 2010
VALID 111200Z - 121200Z
...NO SVR TSTM AREAS FORECAST...
...SYNOPSIS...
A SPLIT-FLOW...LARGE-SCALE PATTERN WILL CONTINUE TO THROUGH THE DAY
TWO PERIOD WITH THE POLAR BRANCH DOMINATED BY AN INTENSE MID- AND
UPPER-LEVEL TROUGH WHICH WILL SHIFT EWD FROM THE ERN PACIFIC ONTO
THE WEST COAST. IN THE LOWER-LATITUDES...A ZONAL SUBTROPICAL JET
WILL STRETCH FROM THE CNTRL PACIFIC EWD ACROSS NRN MEXICO. WEAK
PERTURBATIONS WILL TRANSLATE EWD ALONG THE CYCLONIC SIDE OF THIS
JET...THE MOST NOTABLE OF WHICH WILL GRADUALLY WEAKEN WHILE
TRANSLATING EWD FROM THE SRN ROCKIES INTO BASE OF MEAN RIDGE IN
PLACE OVER THE SRN PLAINS.
IN THE LOW LEVELS...WRN EXTENSION OF SURFACE BOUNDARY INITIALLY
STALLED FROM THE OH VALLEY THROUGH CNTRL PLAINS INTO SRN HIGH PLAINS
WILL REDEVELOP NWD IN RESPONSE TO LEE CYCLONE DEVELOPING OVER THE
NRN HIGH PLAINS. THIS LEE CYCLOGENESIS WILL ALSO SERVE TO ENHANCE A
LEE TROUGH OR DRYLINE OVER THE CNTRL AND SRN HIGH PLAINS SUNDAY.
...CNTRL/SRN PLAINS...
12Z OBSERVED SOUNDINGS INDICATE THAT AN EML IS ALREADY PRESENT
ACROSS THE REGION WITH MIDLEVEL LAPSE RATES OF 8-9 C/KM. THIS EML
WILL BE MAINTAINED THROUGH THE DAY TWO PERIOD OWING TO PREVAILING
SWLY MIDLEVEL FLOW REGIME FROM THE HIGHER TERRAIN OF THE SWRN U.S.
AND NRN MEXICO INTO THE HIGH PLAINS. MEANWHILE...STRENGTHENING SLY
LOW-LEVEL FLOW WILL SUPPORT THE NWD FLUX OF AN INCREASINGLY MOIST
BOUNDARY LAYER BENEATH THE EML PLUME...CONTRIBUTING TO AFTERNOON
MLCAPE APPROACHING 1000-2000 J/KG FROM W-CNTRL/NWRN TX INTO CNTRL
KS.
THE COMBINATION OF FORCING FOR ASCENT ASSOCIATED WITH WEAKENING
MIDLEVEL IMPULSE AND SUSTAINED CONVERGENCE ALONG LEE TROUGH/DRY LINE
AND DECAYING SURFACE FRONT ARE EXPECTED TO SUPPORT INITIAL DIURNAL
STORM DEVELOPMENT OVER PARTS OF SWRN INTO W-CNTRL TX. WITH
TIME...ADDITIONAL STORMS WILL BE POSSIBLE FARTHER N THROUGH THE ERN
TX PNHDL WRN/NRN OK INTO KS ALONG NRN EXTENSION OF LEE
TROUGH/DRYLINE AND RETREATING WARM FRONT.
REGION WILL RESIDE TO THE N OF SUBTROPICAL JET CORE AND WITHIN
MIDLEVEL RIDGE AXIS...RESULTING IN GENERALLY WEAK MID-TROPOSPHERIC
WLY FLOW FIELD AND MARGINAL DEEP-LAYER BULK SHEAR.
NONETHELESS...THE COMBINATION OF THE MODERATE CONVECTIVE INSTABILITY
AND STEEP MIDLEVEL LAPSE RATES SUGGEST A HIGH PROBABILITY OF HAIL
WITH ANY LONGER-LIVED MULTICELL STORM CLUSTERS INTO SUNDAY EVENING.
LOW SEVERE PROBABILITIES WILL BE MAINTAINED DUE TO UNCERTAINTIES IN
WHERE THE STRONGEST AIR MASS DESTABILIZATION WILL OCCUR.
HOWEVER...A CATEGORICAL SLIGHT RISK FOR HAIL MAY BE REQUIRED IN
SUBSEQUENT DAY ONE OUTLOOKS ONCE MORE SPECIFIC FORECAST DETAILS
BECOME CLEARER.
...NRN PLAINS INTO UPPER MS VALLEY...
ELEVATED TSTMS CAPABLE OF SOME HAIL WILL BE POSSIBLE SUNDAY NIGHT
INTO EARLY MONDAY MORNING WITHIN EXIT REGION OF 40+KT LLJ WHERE
CONSIDERABLE AIR MASS MOISTENING IS FORECAST BENEATH NRN EDGE OF EML
PLUME. NO SEVERE WEATHER IS CURRENTLY ANTICIPATED.
..MEAD.. 04/10/2010
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