Damaging Winds in Michigan, May 7, 2001

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
218 PM EST SUN MAY 6 2001

MODELS IN AGREEMENT MOVING WARM FRONT THROUGH FA TONIGHT THEN COLD
FRONT ACROSS AREA MONDAY AFTERNOON AND EVENING AS UPPER LOW IN
NORTHERN PLAINS MOVES EAST. FORECAST PROBLEMS ARE HOW HIGH TO GO
WITH POPS AND TIMING...FOLLOWED BY QUESTION OF POPS TUE INTO FRI.

WARM FRONT FM ERN IA TO SW IN WL CONT TO MOVE NORTH TONIGHT AS SFC
LOW MOVES NORTH THROUGH THE NRN PLAINS AND SW FLOW INCREASES. LATEST
SATELLITE AND LIGHTNING DISPLAY SHOWS TSRA DEVELOPING ALONG AND JUST
BEHIND WMFNT...AS WELL AS OUT AHEAD OF FNT ACRS SW CWA. MODEL OMEGA
FIELDS APPEAR TO HAVE WMFNT AREA HANDLED WELL AND CONT TO MOVE
IT ACRS FA OVERNIGHT WITH HELP OF A WEAK S/W. WL HAVE HIGHEST POPS IN
THE WEST NEAR BETTER MOISTURE AND SLIGHTLY LOWER POPS EAST. WMFNT
CLEARS FA BY SUNRISE MON WITH PARTIAL CLEARING EXPECTED AS ATMS MIXES
BEFORE FROPA. INSTABILITY BY MODELS MAY BE UNDERDONE AS THEY ARE
LIMITING AMOUNT OF CLEARING BEFORE FROPA. EXPECT LOW LEVEL MOISTURE
TO POOL AHEAD AND ALONG FNT...ESPECIALLY AFTER OVERNIGHT RAINS ADD
SOME MUCH NEEDED MOISTURE TO LOW LEVELS. THIS WL RESULT IN SFC DWPTS
INCREASING INTO THE LOWER AND MIDDLE 60S. IF ATMS CAN MIX AND PARTIAL
SS OBSERVED...AFTN TEMPS SHLD REACH MID 70S. MODEL INSTABILITY SHOWS
LI/S TO -5 AND SFC BASED CAPES TO 1500 J/KG BUT MODIFIED SOUNDINGS
WITH HIGHER AFTN TEMPS SUPPORT SIMILAR LI/S BUT INCREASED CAPE TO
OVER 2000 J/KG. MID LEVEL WIND FIELD NOT IMPRESSIVE BUT DOES INCREASE
TO 40-45KTS AND WBZ HEIGHTS IN THE 9KFT-10KFT WL SUPPORT HAIL.
UNIDIRECTIONAL PROFILES SUGGEST LINEAR NATURE TO TSRA ALONG FNT WITH
POTENTIAL FOR HIGH WINDS. GIVEN THESE INGREDIENTS AND SPC SLIGHT RISK
IN DAY2...WL ADD STRONG STORMS TO MONDAY FCST. TIMING IN THE EAST
WILL BE LATE AFTN AND EVENING SO WL CARRY LIKELY POPS BETWEEN THE TWO
PERIODS. MODELS AGREE ON SWEEPING FNT EAST AND QUICKLY DRYING ATMS
OUT BY LATE MONDAY NIGHT WEST AND EARLY TUE EAST.

ATMS RATHER DRY FOR TUE BUT UPPER LEVEL TROF AND STEEP LAPSE RATES
WITH COLD CORE ALOFT WARRANT KEEPING THE LOW CHANCE POPS IN FCST
FOR NOW. AVN BRINGS WEAK S/W ACRS TUE NIGHT AND WED. MEDIUM RANGE
AND LATEST SHORT RANGE MODELS HAVE TRENDED TOWARD A FARTHER N
POSITION WITH UPPER LOW AS IT MOVES ACRS SRN CANADA. OPERATIONAL MRF
REMAINS ODD FCST MODEL WITH ITS CLOSED UPPER LOW OVER SRN GREAT LAKES
THROUGH UPCOMING WEEK. NEXT WEAuK SYSTEM DIVES ACRS AREA FOR THU AND
FRI BUT CONFIDENCE LOW THIS FAR OUT GIVEN RECENT MODEL PERFORMANCES.
AVNX DOES SUPPORT SOME LOW PCPN CHANCES BUT WL LEAVE OUT OF FCST FOR
NOW.

.IWX...NONE.
LASHLEY