SWODY3
SPC AC 300729
DAY 3 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0229 AM CDT THU AUG 30 2007
VALID 011200Z - 021200Z
..NO SVR TSTM AREAS FORECAST...
..SYNOPSIS...
MODELS INDICATE THAT THE STRONGER WESTERLIES WILL REMAIN NEAR/ NORTH
OF THE CANADIAN/U.S. BORDER INTO THE WEEKEND. BUT...THE UPPER FLOW
REGIME IS FORECAST TO BECOME MORE ZONAL...AS THE LEAD
IMPULSE...EMANATING FROM A BROAD NORTHEAST PACIFIC TROUGH...
ADVANCES MORE RAPIDLY EASTWARD ACROSS THE CENTRAL CANADIAN
PROVINCES...THAN A DOWNSTREAM TROUGH PROGRESSES EAST OF THE NORTHERN
ATLANTIC COAST.
TO THE SOUTH/EAST OF THE MID-LEVEL SUBTROPICAL RIDGE ENCOMPASSING A
LARGE PORTION OF THE NATION....SEASONABLE MOISTURE AND INSTABILITY
WILL ONCE AGAIN SUPPORT SUBSTANTIAL THUNDERSTORM ACTIVITY ACROSS THE
GULF COAST STATES. MEANWHILE...WITHIN THE UPPER RIDGE...MONSOONAL
MOISTURE...STRONG HEATING AND FORCING...PRIMARILY ASSOCIATED WITH
OROGRAPHY...WILL LIKELY SUPPORT CONSIDERABLE CONVECTIVE DEVELOPMENT
ACROSS THE GREAT BASIN AND CENTRAL/SOUTHERN ROCKIES INTO THE
SOUTHWESTERN DESERTS. ELSEWHERE...PROBABILITIES FOR THUNDERSTORMS
WILL BE LOW.
..PARTS OF NRN PLAINS/UPR MS VLY...
THE SURFACE CYCLONE AND STRONGER MID-LEVEL HEIGHT FALLS ACCOMPANYING
THE AFOREMENTIONED SHORT WAVE IMPULSE ARE PROGGED TO MIGRATE FROM
CENTRAL SASKATCHEWAN/MANITOBA INTO NORTHERN ONTARIO
SATURDAY/SATURDAY NIGHT. AND...THE BULK OF THE ACCOMPANYING
THUNDERSTORM ACTIVITY WILL LIKELY DEVELOP WELL TO THE NORTH OF THE
INTERNATIONAL BORDER AREA.
HOWEVER...JUST AHEAD OF A SURFACE COLD FRONT...WHICH IS FORECAST TO
ADVANCE THROUGH THE NORTHWESTERN HALF OF NORTH DAKOTA BY LATE
SATURDAY AFTERNOON...MODELS SUGGEST INCREASING LIFT ASSOCIATED WITH
LOW-LEVEL WARM ADVECTION...ALONG THE SOUTHEASTERN PERIPHERY OF THE
STRONGER MID-LEVEL COOLING. THIS FORCING IS PROGGED TO SHIFT FROM
PARTS OF EASTERN NORTH DAKOTA INTO THE UPPER GREAT LAKES REGION BY
LATE SATURDAY NIGHT...AND MAY BECOME STRONG ENOUGH TO OVERCOME
INHIBITION.
IF THIS OCCURS...THE ENVIRONMENT IS EXPECTED TO BE MOIST ENOUGH IN
THE PRESENCE OF STEEP MID-LEVEL LAPSE RATES TO CONTRIBUTE TO MOST
UNSTABLE CAPE UP TO AROUND 2000 J/KG. THIS WOULD BE SUPPORTIVE OF
VIGOROUS UPDRAFTS CAPABLE OF PRODUCING LARGE HAIL IN A WEAK TO
MODERATELY SHEARED FLOW REGIME. AND...THOUGH THE PROBABILITY OF
OCCURRENCE IS LOW...POTENTIAL EXISTS FOR A CONSOLIDATING CLUSTER OF
STORMS BY SATURDAY EVENING. CONVECTION WOULD PROBABLY BE BASED
ABOVE A DECOUPLING BOUNDARY LAYER...BUT FORECAST SOUNDINGS INDICATE
UNSATURATED PROFILES FAVORABLE FOR STRONG EVAPORATIVE COOLING NEAR
HEAVIER RAIN CORES...AND THE RISK FOR STRONG GUSTY WINDS REACHING
THE SURFACE.
.KERR.. 08/30/2007
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-
To unsubscribe from WX-STORM send e-mail to LISTSERV@PO.UIUC.EDU with
"unsub wx-storm" in the body of your message. For more information write chris@lib.siu.edu.
No comments:
Post a Comment