VALID 040100Z – 041200Z

…THERE IS A SLGT RISK OF SVR TSTMS PORTIONS NM…SERN AZ…FAR W
TX…

…SYNOPSIS…
ANOMALOUSLY HIGH-AMPLITUDE PATTERN PERSISTS OVER CONUS…WITH
MID-UPPER LOW INVOF MKC ANCHORING DEEP/QUASISTATIONARY SYNOPTIC
TROUGH THAT EXTENDS FROM LS TO LOWER TX COAST AND SWRN GULF OF
MEXICO. ASSOCIATED CYCLONIC FLOW IS FLANKED BY STG RIDGING FROM
ATLC BERMUDA HIGH…AND FROM SMALLER BUT STILL STG ANTICYCLONE
CENTERED OVER S-CENTRAL/SWRN NV. LITTLE CHANGE IN OVERALL PATTERN
WILL TAKE PLACE THROUGH REMAINDER PERIOD…THOUGH WEAK HEIGHT FALLS
WILL OCCUR OVER PAC NW IN ADVANCE OF SHORTWAVE TROUGH NOW APCHG BC
COAST. VERY MINOR AND PROBABLY CONVECTIVELY GENERATED/ENHANCED
PERTURBATIONS SHOULD RIPPLE NWD ACROSS LOWER GREAT LAKES…OH VALLEY
AND SRN APPALACHIANS REGIONS…EMBEDDED WITHIN BROAD PLUME OF
DEEP-TROPOSPHERIC SLY FLOW.

SFC ANALYSIS AT 23Z SHOWED WAVY…REMNANT…FRONTOLYTIC…
QUASISTATIONARY BAROCLINIC ZONE FROM LOWER GREAT LAKES SSWWD ACROSS
CENTRAL KY AND MID TN TO SERN LA…THEN SWWD ACROSS SHELF WATERS
NEAR TX COAST. THIS BOUNDARY IS MANIFEST ANYMORE PRIMARILY BY WRN
FRINGE OF LOW-LEVEL MOISTURE PLUME…E OF WHICH DEW POINTS UPPER 60S
AND 70S F ARE VERY COMMON…AND W OF WHICH LOWER-THETAE CONTINENTAL
AIR MASS UNDERGOES GREATER NOCTURNAL-DIURNAL THERMAL OSCILLATIONS.
AS SUCH…AIR MASS WAS WARMER W OF FRONT…WITH CONSIDERABLE
CLOUDS/PRECIP TO ITS E HAVING LIMITED DIURNAL SFC WARMING.

…SRN ROCKIES/SRN HIGH PLAINS TO AZ…
SCATTERED TO WIDELY SCATTERED TSTMS…SOME SVR WITH AT LEAST
TRANSIENT SUPERCELLULAR CHARACTERISTICS…HAVE DEVELOPED OVER HIGHER
TERRAIN AND MOVED SWD TO SWWD AROUND SERN RIM OF NV ANTICYCLONE
ALOFT. TSTMS MAY MOVE INTO FAVORABLY MOIST/UNSTABLE BOUNDARY LAYERS
FOR A FEW MORE HOURS WITH RISK OF SVR GUSTS AND OCNL LARGE HAIL.
REF SPC WW 391 AND RELATED MESOSCALE DISCUSSIONS FOR LATEST
NEAR-TERM GUIDANCE. REF MESOSCALE DISCUSSION 1322 FOR INFORMATION
ON ADJOINING PORTIONS SERN AZ/SWRN NM. POTENTIAL BECOMES MORE
ISOLATED/CONDITIONAL FARTHER NW INVOF MOGOLLON RIM REGION.
OVERALL…SVR POTENTIAL ACROSS REGION SHOULD DIMINISH MARKEDLY BY
ABOUT 06Z…AS BOUNDARY LAYER BECOMES PROGRESSIVELY MORE STABLE DUE
TO COMBINATION OF SPREADING OUTFLOWS AND DIABATIC SFC COOLING.

…SERN CONUS…
LOOSELY ORGANIZED BANDS OF SCATTERED TO NUMEROUS TSTMS WILL CONTINUE
OVER PORTIONS TN VALLEY SWD TO MS/AL COASTAL PLAIN…AS WELL AS
ACTIVITY MOVING NWD TO NWWD ACROSS PORTIONS GA AND FL PANHANDLE.
ISOLATED DAMAGING GUSTS REMAIN POSSIBLE WHERE PRECIP-LOADING
ENHANCED DOWNBURSTS OCCUR…AND A TORNADO CANNOT BE RULED OUT
DEFINITIVELY GIVEN POCKETS OF AT LEAST MRGLLY FAVORABLE LOW-LEVEL
SHEAR. HOWEVER…SVR POTENTIAL IS LIMITED BY RELATIVELY
MESSY/CLUSTERED OR LINEAR STORM MODES…AS WELL AS INCREASING
COVERAGE OF PRECIP-STABILIZED AIR.

..EDWARDS.. 07/04/2013