Damaging Winds in Michigan, September 9, 2001

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GAYLORD MI
326 PM EDT SUN SEP 9 2001

LATEST SURFACE ANALYSIS SHOWED A COMPLEX PATTERN ACROSS THE GREAT
LAKES REGION. A COLD FRONT WAS EXTENDING SOUTH THROUGH THE WESTERN
GREAT LAKES...ALONG THE SPINE OF LAKE MICHIGAN. A WAVE WAS EVIDENT
ALONG THE FRONT IN SOUTHERN LAKE MICHIGAN...WITH A WARM FRONT
EXTENDING EAST ACROSS LOWER MICHIGAN. MAIN CONCERNS THIS PACKAGE
REVOLVE AROUND PRECIPITATION AND SEVERE WEATHER POTENTIAL UNTIL THIS
SYSTEM EXITS THE REGION TONIGHT.

12 MODELS IN GOOD AGREEMENT OVERALL. RUN-TO-RUN CONSISTENCY HAS ALSO
BEEN PRETTY GOOD OF LATE. GUIDANCE TEMPERATURES GENERALLY CLOSE AND
REASONABLE.

TONIGHT...SURFACE LOW WILL LIFT NORTHEAST INTO ONTARIO TONIGHT...
DRIVEN BY A STRONG UPPER WAVE AND THE RRQ OF A 150 KNOT 250 MB JET.
THIS FORCING WILL CONTINUE TO PROVIDE SUPPORT FOR WIDESPREAD
SHOWERS AND THUNDERSTORMS. PRECIPITABLE WATER VALUES TO 2 INCHES
WILL PROVIDE THE POTENTIAL FOR HEAVY RAINFALL. GOOD DIRECTIONAL AND
SPEED SHEAR WITH THE APPROACHING LOW AND WARM FRONT SUPPORT SOME
SUPERCELL THUNDERSTORM DEVELOPMENT (AND TORNADOES...SEE SPC WATCH
734). PRECIPITATION WILL TAPER OFF OVERNIGHT AS THE UPPER LOW...JET
AND SURFACE LOW LIFT INTO CANADA...FOLLOWED BY GOOD DNVA/DRYING.

MONDAY...HAVE MAINTAINED A LOW CHANCE OF SHOWERS ACROSS NORTHERN
SECTIONS OF FORECAST AREA. ANOTHER SHORT WAVE AND 110 KNOT JET DIVE
INTO THE BACK OF THE DEPARTING LARGER UPPER WAVE. THIS SECONDARY
WAVE AND JET HAVE TRENDED FURTHER SOUTH THE PAST FEW RUNS...PLACING
FAR NORTHERN SECTIONS OF THE REGION IN THE LFQ OF THE JET.
OTHERWISE...A GRADUAL DECREASE IN CLOUDS CAN BE EXPECTED AS DRIER
AIR AND ANTICYCLONIC FLOW BUILD IN.

MONDAY NIGHT THROUGH TUESDAY NIGHT...ZONAL (SLIGHTLY NORTHWEST) FLOW
ALOFT AND HIGH PRESSURE AT THE SURFACE WILL BRING DRY AND SLIGHTLY
COOLER THAN NORMAL TEMPERATURES TO THE REGION. SOME INCREASE IN
CLOUDS IS LIKELY OVERNIGHT TUESDAY AS WE GET ON THE BACK SIDE OF THE
SURFACE HIGH AND THE NEXT UPPER WAVE APPROACHES.

WEDNESDAY...UPPER WAVE AND ASSOCIATED SURFACE LOW TRACK ACROSS LAKE
SUPERIOR DURING THE DAY...ALONG WITH THE BEST MOISTURE. AS THE LOW
TRACKS EAST...A TROF/COLD FRONT WILL SWING THROUGH THE STATE. THE
TROF/FRONT PASSAGE WARRANT A CHANCE OF SHOWERS AREAWIDE. HOWEVER...
THEY WILL LIKELY NOT BE TOO BIG A DEAL AS THE BEST FORCING REMAINS
IN CANADA.

EXTENDED DISCUSSION...MODELS IN BETTER AGREEMENT TODAY WITH REGARD
TO SCENARIO EXPECTED FOR LATE WEEK. MODEST UPPER TROFFING WILL BE
ACROSS EASTERN CANADA AND THE NORTHEAST UNITED STATES...WITH A
NORTHWEST UPPER FLOW ACROSS THE GREAT LAKES. CANADIAN HIGH PRESSURE
WILL BE WELL ESTABLISHED AT THE SURFACE OVER THE GREAT LAKES REGION
DURING THIS TIME FRAME. THESE FACTORS WILL COMBINE TO BRING DRY BUT
SLIGHTLY COOLER THAN NORMAL CONDITIONS TO THE REGION. FOR SUNDAY...
THE OPERATIONAL MRF BRINGS A STRONGER SHORTWAVE TOWARD THE REGION
WITH AN ASSOCIATED SURFACE RESPONSE. HOWEVER...THIS APPEARS TO BE AN
OUTLIER AT THIS TIME WHEN COMPARED TO THE ENSEMBLES. SO...WILL KEEP
SUNDAY DRY AT THIS TIME WITH A WARM UP AND INCREASE IN CLOUDS AS WE
GET ON THE BACK SIDE OF THE SURFACE HIGH.

.APX...NONE.

BAK

MIZ016>036-041-042-100200-

SEVERE WEATHER OUTLOOK
NATIONAL WEATHER SERVICE GAYLORD MI
105 PM EDT FRI APR 15 2001

...THERE IS A RISK OF SEVERE WEATHER ACROSS PARTS OF NORTHERN LOWER
MICHIGAN THIS AFTERNOON AND EVENING...

* THREAT AREA...NORTHERN LOWER MICHIGAN...PRIMARILY ALONG AND EAST
  OF A LINE FROM ROGERS CITY TO CADILLAC.

* DISPATCHERS...PLEASE NOTIFY YOUR EMERGENCY MANAGERS IMMEDIATELY.
  SPOTTER ACTIVATION MAY BE NEEDED THIS AFTERNOON AND EVENING.

* SEVERE WEATHER THREAT...A FEW THUNDERSTORMS PRODUCING WIND GUSTS
  EXCEEDING 60 MPH. ISOLATED TORNADOES POSSIBLE.

* TIME OF SEVERE WEATHER THREAT...3 PM THIS AFTERNOON TO 10 PM
  TONIGHT.

STAY TUNED TO NOAA WEATHER RADIO OR YOUR LOCAL MEDIA FOR THE LATEST
INFORMATION REGARDING THE SEVERE WEATHER THREAT IN NORTHERN LOWER
MICHIGAN.

ROWLEY

MIZ032>036-041-042-100200-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE GAYLORD MI
305 PM EDT SUN SEP 9 2001

THE STORM PREDICTION CENTER HAS ISSUED A TORNADO WATCH FOR PORTIONS
OF NORTHERN MICHIGAN EFFECTIVE UNTIL 1000 PM EDT SUNDAY EVENING. THIS
WATCH INCLUDES THE FOLLOWING COUNTIES

IN NORTHERN LOWER MICHIGAN
     ROSCOMMON...WEXFORD...GLADWIN...OGEMAW...IOSCO...MISSAUKEE AND
     ARENAC

THIS WATCH INCLUDES THE ADJOINING COASTAL WATERS OF AFFECTED
LAKESHORE COUNTIES.

A TORNADO WATCH MEANS THAT CONDITIONS ARE FAVORABLE FOR THE
DEVELOPMENT OF THUNDERSTORMS CAPABLE OF PRODUCING TORNADOES. IF YOU
LIVE IN OR NEAR THE WATCH AREA...YOU SHOULD REMAIN ALERT TO RAPIDLY
CHANGING WEATHER CONDITIONS. STAY TUNED TO NOAA WEATHER RADIO OR
LOCAL TELEVISION OR RADIO STATIONS FOR FURTHER UPDATES AND POSSIBLE
WARNINGS.