SWODY2
SPC AC 090552
DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1152 PM CST FRI FEB 08 2008
VALID 101200Z - 111200Z
..NO SVR TSTM AREAS FORECAST...
..SYNOPSIS...
A PROGRESSIVE...VIGOROUS SHORT WAVE IMPULSE OF ARCTIC ORIGINS...
WITH A MID-LEVEL COLD CORE TO -40C...IS PROGGED TO DIG INTO THE
GREAT LAKES REGION BY 12Z SUNDAY...BEFORE LIFTING ACROSS NORTHERN
ATLANTIC COASTAL AREAS LATER SUNDAY/SUNDAY NIGHT. MODELS INDICATE
THAT THIS WILL OCCUR IN PHASE WITH A TROUGH IN THE BRANCH OF POLAR
WESTERLIES EMANATING FROM THE NORTHERN PACIFIC...AS AMPLIFICATION
OCCURS ACROSS THE EASTERN PACIFIC THROUGH THE INTERMOUNTAIN WEST AND
ROCKIES.
AS A BUILDING UPPER RIDGE EDGES TOWARD THE PACIFIC COAST...A
SIGNIFICANT DOWNSTREAM SHORT WAVE TROUGH IS FORECAST TO BEGIN
DIGGING ACROSS THE NORTHERN INTERMOUNTAIN AND NORTHERN ROCKIES. AT
THE SAME TIME...A BROAD IMPULSE...WITHIN A WEAKER STREAM EMANATING
FROM THE SUBTROPICAL PACIFIC...IS EXPECTED TO GRADUALLY PROGRESS
ACROSS THE MEXICAN PLATEAU AND PARTS OF THE LOWER RIO GRANDE
VALLEY...AS AN UPSTREAM SYSTEM DIGS TOWARD THE BAJA SPUR.
IN RESPONSE TO THE EVOLVING UPPER PATTERN...A SURFACE TROUGH LIKELY
WILL DEEPEN TO THE LEE OF THE ROCKIES DURING THIS PERIOD...AS A
LARGE COLD SURFACE RIDGE BEGINS TO RETREAT TO THE EAST OF THE
MISSISSIPPI VALLEY. THIS WILL BE ACCOMPANIED BY A DEVELOPING RETURN
FLOW OFF THE WESTERN GULF OF MEXICO...WHERE SURFACE DEW POINTS ARE
NOW THE LOWER/MID 60S...AND THE BOUNDARY LAYER SHOULD NOT BE
SUBSTANTIALLY IMPACTED BY THE NEW ARCTIC INTRUSION INTO THE EASTERN
STATES.
..EAST CENTRAL PLAINS INTO THE OZARK PLATEAU...
NORTHWESTERLY TO WESTERLY LOWER/MID TROPOSPHERIC FLOW IS EXPECTED TO
MAINTAIN A RELATIVELY WARM ELEVATED MIXED LAYER ACROSS MUCH OF THE
CENTRAL/SOUTHERN PLAINS THROUGH THIS PERIOD. AND...IN THE WAKE OF
AN ARCTIC INTRUSION NOW IN THE PROCESS OF NOSING SOUTHEAST OF THE
NORTH CENTRAL STATES...A SHARP LOW-LEVEL BAROCLINIC ZONE IS FORECAST
TO SET UP ACROSS THE SOUTH CENTRAL PLAINS/OZARK PLATEAU REGION.
MOISTURE RETURNING FROM THE WESTERN GULF OF MEXICO...SUNDAY INTO
SUNDAY EVENING...WILL OVERRUN THIS BOUNDARY...BUT MAY BE INITIALLY
CAPPED ACROSS MUCH OF OKLAHOMA/SOUTHWEST ARKANSAS. HOWEVER...WITH
TIME...MODELS INDICATE THAT A STRENGTHENING SOUTHERLY LOW-LEVEL JET
WILL STEEPEN ISENTROPIC ASCENT ON THE NOSE OF THE ELEVATED WARM
LAYER...ACROSS PARTS OF EASTERN KANSAS INTO THE MISSOURI
OZARKS...POSSIBLY ADJACENT AREAS OF NORTHEAST OKLAHOMA/NORTHERN
ARKANSAS. AND...SUFFICIENT MOISTENING IS EXPECTED FOR AT LEAST WEAK
DESTABILIZATION SUPPORTIVE OF SCATTERED THUNDERSTORM ACTIVITY BY
LATE SUNDAY NIGHT. WHILE SHEAR IN THE CLOUD BEARING LAYER WILL BE
FAVORABLE FOR UPDRAFT ROTATION...CAPE IS NOT CURRENTLY EXPECTED TO
BECOME SUFFICIENT TO SUPPORT AN APPRECIABLE SEVERE THREAT... THOUGH
COOL PROFILES COULD ALLOW SOME SMALL HAIL TO REACH THE SURFACE IN
HEAVIER CONVECTIVE CORES.
.KERR.. 02/09/2008
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