877
FXUS63 KDLH 212005
AFDDLH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DULUTH MN
305 PM CDT THU AUG 21 2008
DISCUSSION
MAIN FCST CONCERNS IN SHORT TERM ARE RA CHC IN WIS ZONES THIS
EVENING...AND INCREASING TSRA THREAT FRI/FRI NIGHT.
CURRENT SFC ANALYSIS SHOW A STRONG PRESSURE GRADIENT OVER THE UPR
MIDWEST...RESULTING IN A BREEZY SRLY FLOW WITH MOST AREAS IN MN
GUSTING INTO THE 20-30 KT RANGE. ALTHOUGH THE THERMAL GRADIENT
WILL WEAKEN OVERNIGHT...WINDS WILL REMAIN GUSTY AS COLD FRONT
APPROACHES WRN MN AND ALLOWS FOR A 30-40 KT LLJ TO SHIFT E OVER THE
CWA. THIS WILL ALSO FOR INCREASING THICKNESSES AND WARMER OVERNIGHT
LOWS...WITH MOST AREAS REMAINING IN THE MID TO UPR 60S. WINDS WILL
INCREASE RAPIDLY AGAIN AFTER DAY BREAK FRIDAY AS THE FRONT
CONTINUES TO PUSH EAST OVER THE FA THROUGH FRI EVENING. MODELS
ARE IN GOOD AGREEMENT WITH THE SYNOPTIC FEATURES...WITH THE SFC
LOW STRENGTHENING OVER SRN MANITOBA AS IT BECOMES VERTICALLY
STACKED WITH THE CUT-OFF UPR LVL LOW. THE COLD FRONT SWEEPS
QUICKLY EAST OVER THE REGION WITH A STRONG BAROCLINIC ZONE AND POST
FRONTAL DRY SLOT. HOWEVER...MODELS DIVERGE SOMEWHAT IN TIMING OF
THE FROPA AND ASSOC DRY AIR INTRUSION...WITH THE NAM BEING THE
MODEL OF CHOICE WITH THE SLOWER PROGRESSION.
CONDITIONS WILL BE FAVORABLE FOR ISOLD SVR STORMS FRIDAY
AFTERNOON/EARLY EVENING AS THE INSTABILITY INCREASES AND CAN OVER
COME THE WEAKENING CAP. ATTM...THE BEST THREAT FOR STRONG TO SVR
STORMS WILL BE OVER NRN WISCONSIN MAINLY AFT 21Z.
IMPRESSIVE CAA REGIME SETS UP AFTER THE FROPA BRINGING A COOL
DOWN THE WEEKEND AS H85 TEMPS ON THE SINGLE DIGITS SINK INTO NRN
MN. DECREASED HIGHS ON SAT QUITE A BIT...CLOSER TO MET/MAV
GUIDANCE.
AVIATION
GENERALLY VFR CONDS EXPECTED THRU THE TAF PD. THE EXCEPTION WILL BE
TEMPO MVFR CIGS IN SHRA OR TS...BEGINNING THIS EVE IN THE S AND
SPREADING NWD OVNGT. SCT TSRA EXPECTED THRU THE DAY ON FRI AS
WELL...WHEN VSBY MAY DIP BRIEFLY INTO THE MVFR CAT.
POINT TEMPS/POPS...
DLH 80 65 81 60 / 10 20 50 60
INL 87 66 79 52 / 10 20 50 40
BRD 86 67 84 56 / 10 10 40 20
HYR 82 64 82 63 / 40 50 30 60
ASX 82 64 82 63 / 30 40 20 60
DLH WATCHES/WARNINGS/ADVISORIES
MN...NONE.
WI...NONE.
LS...NONE.
GRANING/04
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