[SWODY1] SWODY1

[Severe Weather Outlook Day 1]

ACUS01 KWNS 040552
SWODY1
SPC AC 040551

DAY 1 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
1151 PM CST FRI MAR 03 2006

VALID 041200Z - 051200Z

...THERE IS A SLGT RISK OF SVR TSTMS LATE THIS AFTN/EVE ACROSS PARTS
OF THE SRN HIGH PLAINS....

IN THE WAKE OF AN AMPLIFYING UPPER TROUGH NEAR THE ATLANTIC
COAST...RIDGING HAS COOLED/DRIED LOW-LEVEL ENVIRONMENT ACROSS MOST
AREAS EAST OF THE ROCKIES.  MODELS SUGGEST UPPER TROUGHING WILL
SHIFT AWAY FROM ATLANTIC COASTAL AREAS TODAY...BUT MODIFICATION OF
LOWER LEVELS WILL BE SLOWER TO OCCUR.

ONLY THE SOUTHERN HIGH PLAINS AND RIO GRANDE VALLEY HAVE BEEN
RELATIVELY UNAFFECTED BY THE COLD/DRY INTRUSION...AND BOUNDARY LAYER
MOISTURE IS ALREADY IN THE PROCESS OF RETURNING NORTHWARD...  WEST
OF THE RIO GRANDE RIVER TOWARD THE TEXAS BIG BEND.  IN A NARROW
TONGUE...THIS MOISTURE SEEMS LIKELY TO ADVECT BACK INTO THE SOUTHERN
HIGH PLAINS TODAY...AS SOUTHERLY LOW-LEVEL FLOW PERSISTS/
STRENGTHENS AHEAD OF UPPER TROUGH CONTINUING EASTWARD OUT OF THE
GREAT BASIN.

UPPER SYSTEM HAS LIFTED OUT OF BASE OF BROADER SCALE EASTERN
PACIFIC/WESTERN U.S. UPPER TROUGH...AND IS FORECAST TO GRADUALLY
PROGRESS INTO MEAN UPPER RIDGE POSITION OVER THE PLAINS BY 12Z
SUNDAY.  THIS WILL OCCUR AS ANOTHER CLOSED LOW DEVELOPS OFF THE
PACIFIC COAST IN RESPONSE TO VIGOROUS SHORT WAVE IMPULSE NOW DIGGING
OUT OF THE NORTHEAST PACIFIC.  

MID-LEVEL HEIGHT/TEMPERATURE RISES ACROSS THE WEST/INTERMOUNTAIN
WEST WILL LIMIT CONVECTIVE POTENTIAL ACROSS THAT AREA TODAY. 
BUT...MID-LEVEL HEIGHT FALLS/STEEPENING LAPSE RATES AND MOISTURE
RETURN ACROSS THE SOUTHERN HIGH PLAINS INTO THE CENTRAL PLAINS
SHOULD SUPPORT CONTINUING/INCREASING CONVECTIVE POTENTIAL LATER THIS
AFTERNOON AND TONIGHT.

...SOUTHERN HIGH PLAINS...
NARROW TONGUE OF LOWER/MID 50S DEW POINTS IS EXPECTED TO EXTEND
NORTH OF THE LOWER RIO GRANDE VALLEY THROUGH THE TEXAS/NEW MEXICO
BORDER AREA BY LATE THIS AFTERNOON.  THOUGH A RELATIVELY WEAK
MOISTURE RETURN...MODELS SUGGEST SEASONABLY STRONG HEATING WILL
OCCUR ALONG DRY LINE...AND CONTRIBUTE TO MIXED LAYER CAPE OF 500 TO
1000 J/KG.  THIS WILL OCCUR BENEATH MODERATELY STRONG SOUTHWESTERLY
MID-LEVEL FLOW...SUPPORTIVE OF DEEP LAYER SHEAR ON THE ORDER OF 40
TO 50 KT.  

SUPPRESSION OF MID-LEVEL INHIBITION DURING/SHORTLY AFTER THE PEAK
HEATING HOURS APPEARS LIKELY TO ALLOW INITIATION OF SCATTERED
THUNDERSTORM ACTIVITY. A FEW VIGOROUS STORMS SHOULD EVENTUALLY
EVOLVE...INCLUDING ISOLATED SUPERCELLS WITH ENHANCED RISK FOR LARGE
HAIL/GUSTY WINDS.  THREAT MAY NOT CONTINUE MUCH BEYOND
04/01-02Z...AS MID/UPPER FORCING SHIFTS ABOVE COOLER MORE STRONGLY
CAPPED LOW-LEVEL ENVIRONMENT EAST OF THE HIGH PLAINS.

...CENTRAL PLAINS INTO MID MISSISSIPPI VALLEY....
STRONGER MID-LEVEL FORCING ASSOCIATED WITH THE GREAT BASIN TROUGH
WILL SPREAD ACROSS THE ROCKIES INTO THE NORTHERN AND CENTRAL PLAINS
THIS AFTERNOON.  LOW-LEVEL MOISTURE RETURN WILL BE QUITE LIMITED
THIS FAR NORTH...BUT LAPSE RATES STEEP ENOUGH FOR AT LEAST MARGINAL
SEVERE HAIL POTENTIAL SEEM LIKELY TO DEVELOP AS FAR NORTH AS
SOUTHWEST/CENTRAL NEBRASKA.  FORCING FOR CONVECTIVE DEVELOPMENT
ACROSS THIS REGION WILL BE AUGMENTED BY SPEED MAXIMA IN A SOUTHERN
BRANCH OF THE POLAR WESTERLIES...WHICH IS PROGGED TO NOSE ACROSS THE
TEXAS/OKLAHOMA PANHANDLE REGION BY EARLY THIS EVENING. 

AS JET STREAK CONTINUES TOWARD THE LOWER MISSOURI VALLEY OVERNIGHT
...THUNDERSTORMS ARE EXPECTED TO DEVELOP EASTWARD IN STRONGER
LOW-LEVEL WARM ADVECTION REGIME ACROSS THE CENTRAL PLAINS. LACK OF
BETTER MOISTURE WILL LIMIT CAPE...BUT CONVECTIVE INSTABILITY/SHEAR
MAY CONTINUE TO BE SUPPORTIVE OF AT LEAST SMALL TO MARGINALLY SEVERE
HAIL IN STRONGER CELLS.

..KERR/CROSBIE.. 03/04/2006