SWODY1
SPC AC 080544
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1144 PM CST SAT JAN 07 2012
VALID 081200Z - 091200Z
...NO SVR TSTM AREAS FORECAST...
...SYNOPSIS...
PHASING OF RIDGING WITHIN TWO DISTINCT BELTS OF WESTERLIES
APPROACHING THE PACIFIC COAST STILL APPEARS LIKELY TO REMAIN
RELATIVELY SHORT-LIVED. MODELS CONTINUE TO INDICATE THAT A
COMPONENT WITHIN ONE STREAM WILL ADVANCE INLAND NEAR THE
CANADIAN/U.S. BORDER AREA FASTER THAN A COMPONENT WITHIN A MORE
AMPLIFIED STREAM TO THE SOUTH...ACROSS THE CALIFORNIA COAST. AS THE
NORTHERN FEATURE SHIFTS ACROSS AND EAST THE CANADIAN/NORTHERN U.S.
ROCKIES...A CLOSED LOW...EVOLVING FROM A DIGGING SHORT WAVE IMPULSE
DOWNSTREAM OF THE CALIFORNIA RIDGE...MAY BECOME MORE DETACHED FROM
THE STRONGER WESTERLIES AS IT SETTLES ACROSS THE SOUTHERN U.S.
PLATEAU AND ROCKIES/NORTHERN MEXICAN PLATEAU REGION.
VARIABILITY EXISTS AMONG THE MODELS CONCERNING ANOTHER IMPULSE
EXPECTED TO SPLIT OFF THE NORTHERN STREAM...BEFORE DIGGING ACROSS
PORTIONS OF THE NORTH CENTRAL PLAINS AND MIDDLE MISSISSIPPI VALLEY
BY 12Z MONDAY...AND ITS POSSIBLE INFLUENCE ON THE MOTION OF THE
SOUTHWESTERN LOW. FURTHER UNCERTAINTY EXISTS CONCERNING THE
INTERACTION OF THE SOUTHWESTERN LOW WITH ANOTHER BELT OF STRONGER
FLOW EMERGING FROM THE SUBTROPICAL PACIFIC. MUCH OF THIS BECOMES
MORE PRONOUNCED BEYOND THIS FORECAST PERIOD...BUT MAY BE OF
SIGNIFICANCE TO CONVECTIVE POTENTIAL THAT COULD INCREASE ACROSS A
LARGE PORTION OF CENTRAL/SOUTHERN AND EASTERN TEXAS LATE THIS
EVENING INTO EARLY MONDAY.
THE RISK OF THUNDERSTORMS PROBABLY WILL REMAIN NEGLIGIBLE THROUGH AT
LEAST THE DAYTIME HOURS TODAY ACROSS MUCH OF THE SOUTHERN
PLAINS/WESTERN GULF COAST AND LOWER RIO GRANDE VALLEY REGION.
HOWEVER...AN INFLUX OF MOISTURE IN THE PRESENCE OF LOW-LEVEL WARM
ADVECTION ACROSS UPPER TEXAS AND CENTRAL GULF COASTAL AREAS...INTO
THE VICINITY OF A STALLED FRONT ACROSS THE NORTHERN GULF STATES...IS
EXPECTED TO SUPPORTED SCATTERED THUNDERSTORMS. SOME OF THIS
ACTIVITY COULD BECOME SURFACE OR NEAR SURFACE BASED ACROSS CENTRAL
LOUISIANA INTO PARTS OF CENTRAL/SOUTHERN MISSISSIPPI. DESPITE
STRONG DEEP LAYER SHEAR...WEAK LOW-LEVEL WIND
FIELDS...WEAK/UNCERTAIN FORCING BENEATH BROADLY ANTICYCLONIC
MID-LEVEL FLOW...AND LIMITED CAPE DUE TO WEAK MID-LEVEL LAPSE RATES
ALL SEEM TO MINIMIZE THE RISK FOR SEVERE STORMS.
...TEXAS...
MUCH DEPENDS ON THE MOTION OF THE DEVELOPING UPSTREAM LOW...AND/ OR
FORCING WITH ANY SMALLER SCALE UPPER IMPULSE LIFTING NORTHEAST OF
THE RIO GRANDE VALLEY...AHEAD OF IT...WHICH ALSO REMAINS UNCERTAIN.
HOWEVER...IT CURRENTLY SEEMS POSSIBLE THAT ADVECTION OF INCREASINGLY
RICH MOISTURE /PW IN EXCESS OF 1.25 IN/ ON MODEST SOUTHERLY
LOW-LEVEL FLOW COULD CONTRIBUTE TO POTENTIAL FOR VIGOROUS STORM
DEVELOPMENT BY 09-12Z MONDAY...IF NOT BEFORE... ACROSS MIDDLE TEXAS
COASTAL AREAS...AND POSSIBLY INLAND TOWARD THE HILL COUNTRY. IN THE
PRESENCE OF INCREASING CAPE...RELATIVELY COOL THERMODYNAMIC
PROFILES...AND STRONG DEEP LAYER SHEAR BENEATH 40-50 KT
SOUTHWESTERLY 500 MB FLOW...THE ENVIRONMENT COULD BECOME CONDUCIVE
TO STORMS CAPABLE OF PRODUCING MARGINALLY SEVERE HAIL. ALTHOUGH
LOW-LEVEL HODOGRAPHS MAY ALSO BE ENLARGING...LINGERING WEAKNESSES
EVIDENT IN FORECAST SOUNDINGS IN THE LOWER/MID TROPOSPHERE SUGGEST
THAT THE TORNADIC POTENTIAL IS MORE NEGLIGIBLE.
..KERR/LEITMAN.. 01/08/2012
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