[SWODY2] SWODY2

[SWODY2 at goshenarc.org]

ACUS02 KWNS 220550
SWODY2
SPC AC 220549

DAY 2 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
1249 AM CDT MON AUG 22 2005

VALID 231200Z - 241200Z

GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM DRT AUS 10 E ACT MWL
BGS FST 45 WSW MRF ...CONT... IPL 50 ESE DAG DRA LOL 4LW BNO LWS 4OM
40 NNW 4OM ...CONT... 65 N DVL 25 NNW ATY FSD 20 SE OMA 10 N COU BWG
10 SSE BLF 15 ENE WAL.

...NO SVR TSTM AREAS FORECAST...

IN RESPONSE TO AMPLIFICATION IN SOUTHERN BRANCH OF POLAR JET...A
LESS PROGRESSIVE UPPER FLOW PATTERN CONTINUES TO EVOLVE OVER THE
U.S. AND MUCH OF CANADA.  ONE CLOSED LOW HAS ALREADY DEVELOPED
WITHIN LARGE UPPER TROUGH ACROSS QUEBEC/ONTARIO AND THE LOWER GREAT
LAKES. EASTWARD MIGRATION OF THIS SYSTEM WILL SLOW BY TUESDAY
ACROSS THE NORTH ATLANTIC COAST...AS ANOTHER CLOSED LOW EVOLVES IN
LARGE UPSTREAM TROUGH DIGGING ACROSS THE CANADIAN/NORTHERN U.S.
ROCKIES.

SUPPRESSION OF SUBTROPICAL RIDGE IS EXPECTED TO PERSIST THROUGH THIS
PERIOD EAST OF THE APPALACHIANS...AS FAR SOUTH AS THE SOUTHERN MID
ATLANTIC COASTAL STATES.  HOWEVER...AS LOW AMPLITUDE TROUGH IN
SUBTROPICAL STREAM LIFTS OUT OF THE SOUTHERN PLATEAU THROUGH THE
CENTRAL ROCKIES/HIGH PLAINS...UPPER RIDGE IS FORECAST TO SLOWLY
BUILD NORTHWARD THROUGH THE SOUTHERN PLAINS AND LOWER MISSISSIPPI
VALLEY.

...HIGH PLAINS...
SURFACE LOW DEVELOPING TODAY ACROSS CENTRAL/EASTERN MONTANA IS
PROGGED TO LIFT NORTHWARD AND WEAKEN ACROSS SASKATCHEWAN/MANITOBA
TUESDAY.  AS THIS OCCURS...MODELS SUGGEST NEW LOW WILL FORM IN 
PRE-FRONTAL SURFACE TROUGH ACROSS SOUTHEAST MONTANA BY LATE TUESDAY
AFTERNOON...WITH TROUGH AXIS EXTENDING SOUTHWARD THROUGH THE CENTRAL
HIGH PLAINS.  THIS IS NORTH OF SURFACE FRONT EXPECTED TO LINGER
ACROSS THE SOUTHERN PLAINS...FROM THE TEXAS/OKLAHOMA PANHANDLE
REGION THROUGH THE RED RIVER VALLEY...AND LACK OF MORE SIGNIFICANT
NORTHWARD MOISTURE RETURN WILL BE ONE FACTOR LIMITING SEVERE THREAT
THIS FORECAST PERIOD.  ADDITIONALLY...MID/UPPER FLOW ACROSS NORTHERN
PLAINS...SOUTH/EAST OF DIGGING TROUGH IN POLAR WESTERLIES...IS
EXPECTED TO REMAIN WEAK AND SOUTHERLY THROUGH AT LEAST TUESDAY
EVENING.

DESPITE LIMITING FACTORS...VERY STEEP LAPSE RATES WILL CONTRIBUTE TO
FAVORABLE ENVIRONMENT FOR VIGOROUS CONVECTIVE DEVELOPMENT.  ISOLATED
STRONGER STORMS MAY PRODUCE MARGINALLY SEVERE HAIL AND AN ISOLATED
DOWNBURST OR TWO...BEFORE WEAKENING DURING THE EVENING WITH LOSS OF
DAYTIME HEATING.

FARTHER SOUTH...STRONGER FORCING ASSOCIATED WITH SUBTROPICAL IMPULSE
MAY NOT OVERSPREAD PARTS OF EASTERN COLORADO/WESTERN NEBRASKA AND
KANSAS UNTIL AFTER DARK.  HOWEVER...MODELS SUGGEST A BIT MORE
PRONOUNCED VEERING WITH HEIGHT IN LOWER TO MID LEVELS DURING THE
PEAK HEATING HOURS ACROSS THIS REGION...WHERE LOW-LEVEL MOISTURE
RETURN MAY CONTRIBUTE TO MIXED LAYER CAPE OF 2000 TO 3000 J/KG.  AN
ISOLATED SHORT-LIVED SUPERCELL OR TWO APPEARS POSSIBLE ...BUT SEVERE
THREAT MAY DIMINISH FAIRLY QUICKLY DURING THE EVENING AS BOUNDARY
LAYER COOLS/STABILIZES.

...SOUTHEAST STATES...
AS FRONT ACROSS THE SOUTH ATLANTIC COAST STATES WEAKENS...MOIST
UPSLOPE FLOW IS PROGGED TO DEVELOP TUESDAY.  IT IS STILL UNCERTAIN
AS TO WHETHER A SHORT WAVE ROTATING INTO BASE OF LARGER-SCALE
EASTERN TROUGH WILL CONTRIBUTE TO FORCING FOR CONVECTIVE DEVELOPMENT
ACROSS THE SOUTHERN APPALACHIANS DURING THE DAYTIME HOURS. 
HOWEVER...SCATTERED THUNDERSTORM ACTIVITY APPEARS LIKELY IN RESPONSE
TO HEATING OF WEAKLY CAPPED BOUNDARY LAYER.  THOUGH LOW/MID-LEVEL
WINDS WILL BE LIGHT...VEERING WITH HEIGHT BENEATH MODERATE WESTERLY
HIGH-LEVEL FLOW MAY CONTRIBUTE TO SUFFICIENT SHEAR FOR AT LEAST
BRIEF UPDRAFT ROTATION IN STRONGEST CELLS.  IF THIS
OCCURS...POTENTIAL FOR HAIL/GUSTY WINDS WILL BE ENHANCED.

..KERR.. 08/22/2005

...NOTICE...
THE STATION RELATIVE POINTS IN THIS PRODUCT ARE NOW AVAILABLE
SEPARATELY UNDER THE WMO HEADINGS WUUS01 PTSDY1...
WUUS02 PTSDY2...WUUS03 PTSDY3.  THE INCLUSION OF POINTS
IN THIS DISCUSSION WILL BE DISCONTINUED AFTER THE 2005
CONVECTIVE SEASON.  A PUBLIC NOTIFICATION STATEMENT (PNS)
WILL PROVIDE DETAILS ON THE TRANSITION.