Damaging Winds in Michigan, September 19, 2005

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
1148 AM EDT MON SEP 19 2005

.DISCUSSION...
UPDATE CONCERNS ON QPF AMOUNTS AND WINDS

CURRENT WEATHER...15Z WATER VAPOR LOOP AND RUC 500MB HEIGHT ANALYSIS
SHOWED A LARGE UPPER LEVEL HIGH ALONG THE GULF COAST WITH NEARLY
ZONAL FLOW ACROSS THE NORTHERN TIER OF THE U.S.. HOWEVER THERE IS A
SHRTWV TROUGH MOVING THROUGH THIS ZONAL FLOW WHICH IS OVER
MINNESOTA. IMMEDIATELY AHEAD OF THE SHRTWV WAS A LINE OF SHOWERS AND
THUNDERSTORMS WHICH EXTENDS FROM THE ARROWHEAD OF MN SOUTHWARD DOWN
I-35 TO HINCKLEY ON KDLH RADAR. AHEAD OF THIS LINE WAS A MORE BROAD
AREA OF SHOWERS WITH A FEW EMBEDDED THUNDERSTORMS OVER UPPER
MICHIGAN. THIS AREA OF PRECIPITATION IS ASSOCIATED WITH ISENTROPIC
LIFT AND MID LEVEL FRONTOGENESIS. SOME OF THE RAIN HAS COME DOWN
PARTICULARLY HEAVY WITH RAINFALL AMOUNTS ALREADY APPROACHING ONE
HALF OF AN INCH HERE AT THE OFFICE AT THE MOMENT. THERE DOES APPEAR
TO BE SOME LET UP OF THE PRECIPITATION ACROSS NORTHERN WISCONSIN BUT
WITH THE APPROACH OF THE SHRTWV...THIS WILL PROBABLY BE TEMPORARY.
ANOTHER ITEM TO NOTE IS TWO UPPER LEVEL JETS. AT 250MB AT 12Z THERE
WAS A 90 KT JET OVER NEBRASKA WITH ANOTHER 90 KT JET OVER
INTERNATIONAL FALLS. AT THE SURFACE...LOW PRESSURE OF 1011 MB WAS
LOCATED JUST TO THE EAST OF LACROSSE WITH THE BEST PRESSURE FALLS ON
THE ORDER OF 1 MB/HR LOCATED NEAR APPLETON WISCONSIN.

THIS AFTERNOON AND TONIGHT...SHRTWV TROUGH SHOULD CONTINUE ITS
EASTWARD MOVEMENT...CROSSING UPPER MICHIGAN BETWEEN 18-00Z. MANY
FACTORS ARE COMING TOGETHER TO PRODUCE A HEAVY RAINFALL EVENT. FIRST
WILL BE THE DYNAMICAL FORCING AHEAD OF THE SHRTWV ITSELF. NEXT IS
UPPER DIVERGENCE FROM THE TWO UPPER LEVEL JETS HEADING NORTHEASTWARD
TOWARDS UPPER MICHIGAN (COUPLED JET STRUCTURE). THIRD WILL BE THE
ISENTROPIC LIFT AHEAD OF THE SHRTWV TROUGH. FOURTH...PRECIPITABLE
WATER IS PROGGED TO BE AROUND 1.4 INCHES WHICH IS NEARLY 200 PERCENT
OF NORMAL. FINALLY...INCREASING FRONTOGENESIS WILL RESULT IN
ADDITIONAL LIFT. THESE ALL APPEAR TO BE MAXIMIZED ACROSS WESTERN AND
NORTH CENTRAL UPPER MICHIGAN...WHICH IS SHOWN BY THE 06Z/12Z NAM AND
12Z RUC. HAVE FOLLOWED QPF AMOUNTS SIMILAR TO THAT OF THE 12Z NAM
WHICH INDICATES UPWARDS OF 1-2 INCHES OVER NORTH CENTRAL UPPER
MICHIGAN BETWEEN 18-00Z. THESE FACTORS WILL ALSO AID IN DEEPENING
THE SURFACE LOW AS IT MOVES TOWARDS NORTHERN LOWER MICHIGAN/STRAITS
OF MACKINAC AREA. AS A RESULT...EXPECTING WINDS TO
INCREASE...PARTICULARLY DURING THE 19-02Z PERIOD OVER EASTERN LAKE
SUPERIOR AND NORTHERN LAKE MICHIGAN. CURRENT SMALL CRAFT ADVISORIES
AND GALE WARNING ON NORTHERN LAKE MICHIGAN LOOK REASONABLE.

WITH THE RAPID PROGRESSION OF THE SHRTWV TROUGH...SHOULD NOT HAVE TO
WORRY ABOUT ANY FLOODING CONCERNS...ESPECIALLY SINCE A LOT OF THIS
RAIN IS GOING OVER PLACES THAT HAVE BEEN PARTICULARLY DRY.
ALSO...RAIN WILL PROBABLY CUT OFF QUICKLY THIS EVENING AND THIS
TREND CAN ALREADY BE SEEN BEHIND THE SHRTWV WHERE EVEN SKIES CLEAR
OUT PRETTY QUICK. WITH THE BIG DRYING TAKING PLACE (SEEN ON THE BIS
SOUNDING)...FOG WILL BECOME A CONCERN AS IT WAS OVER NORTH DAKOTA.
MAY CHANGE THE PATCHY FOG TO AREAS OF DENSE FOG ON THE NEXT FORECAST
ISSUANCE.

&&

.PREV DISCUSSION...

FOR TUESDAY...LOOKS VERY WARM WITH 850 MB TEMPERATURES UP TO 14C AND
MIXING THIS DOWN TO THE SFC GIVES ME LOWER 80S. THIS SEEMS POSSIBLE
WITH A WEST-SOUTHWEST WIND WHICH WOULD AID IN SOME DOWNSLOPE...BUT
WENT UPPER 70S FOR HIGHS AS SUN ANGLE IS WEAK THIS TIME OF YEAR AND
MIGHT NOT BE ABLE TO MIX UP TO 850 MB TOO MUCH LONGER. ALSO SEEMS
LIKE A WEAK DRY FRONT COMES THROUGH LATE ON TUESDAY BASED ON
1000-500 MB THICKNESS PACKING AS THICKNESSES LOWER SLIGHTLY FOR WED.
FOR THIS REASON...BELIEVE TUE WILL BE THE WARMEST DAY OF THE WEEK
AND SLIGHTLY COOLER TEMPERATURES FOR WED...BUT WILL STILL BE ABOVE
NORMAL.

PULLED POPS OUT OF THE WEST FOR EARLY WED NIGHT AS SEEMS LIKE WITH
ZONAL FLOW...THE MID LEVELS WOULD START OUT DRY AND WILL TAKE SOME
TIME TO MOISTEN THESE UP. PUSHED TIMING OF THE NEXT SYSTEM BACK
ABOUT 6-12 HOURS BECAUSE OF POSSIBILITY OF DRY MID LEVELS. OTHER
THAN THAT...DID NOT MAKE TOO MANY CHANGES TO THE GOING FORECAST FOR
TEMPERATURES.

&&

.MQT...WATCHES/WARNINGS/ADVISORIES...GALE WARNING LMZ248 TONIGHT.

&&

AJ (DISCUSSION)
MICHELS (PREV DISCUSSION)

HAZARDOUS WEATHER OUTLOOK...UPDATED
NATIONAL WEATHER SERVICE MARQUETTE MI
1003 AM EDT MON SEP 19 2005

MIZ001>007-009>014-084-085-201200-
ALGER-BARAGA-DELTA-DICKINSON-GOGEBIC-IRON-KEWEENAW-LUCE-MARQUETTE-
MENOMINEE-NORTHERN HOUGHTON-NORTHERN SCHOOLCRAFT-ONTONAGON-
SOUTHERN HOUGHTON-SOUTHERN SCHOOLCRAFT-
1003 AM EDT MON SEP 19 2005

THIS HAZARDOUS WEATHER OUTLOOK IS FOR WESTERN AND CENTRAL UPPER
MICHIGAN.

.DAY ONE...THIS AFTERNOON AND TONIGHT

A FEW THUNDERSTORMS WILL OCCUR ACROSS WEST AND CENTRAL UPPER
MICHIGAN THIS AFTERNOON AND OVER CENTRAL UPPER MICHIGAN THIS
EVENING. ALTHOUGH NO SEVERE WEATHER IS EXPECTED FROM THESE
STORMS...HEAVY RAINFALL MAY OCCUR...ESPECIALLY ACROSS WESTERN AND
NORTH CENTRAL UPPER MICHIGAN.

GALES ARE EXPECTED IN THE NEARSHORE WATERS FROM SEUL CHOIX POINT TO
POINT DETOUR LATE THIS AFTERNOON THROUGH MIDNIGHT TONIGHT. SMALL
CRAFT ADVISORY CONDITIONS IN THE BAY OF GREEN BAY NEARSHORE WATERS
CAN BE EXPECTED LATE THIS AFTERNOON THROUGH MIDNIGHT TONIGHT. SMALL
CRAFT ADVISORY CONDITIONS CAN ALSO BE EXPECTED TONIGHT IN THE LAKE
SUPERIOR NEARSHORE WATERS FROM THE HURON ISLANDS TO WHITEFISH POINT.

.DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY

THERE IS A CHANCE OF THUNDERSTORMS LATE WEDNESDAY NIGHT ACROSS THE
WESTERN HALF OF UPPER MICHIGAN.

THERE IS A CHANCE OF THUNDERSTORMS THURSDAY THROUGH THURSDAY
NIGHT...AND AGAIN SATURDAY THROUGH SATURDAY NIGHT.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS NOT ANTICIPATED...BUT RAINFALL REPORTS WOULD
BE GREATLY APPRECIATED.

ADDITIONAL WEATHER INFORMATION MAY BE OBTAINED AT THE FOLLOWING URL:

HTTP://WWW.WEATHER.GOV/MQT (ALL LOWER CASE)

MICHELS/AJ