Severe Thunderstorm Warning 49, NWS Marquette, MI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
1122 AM EDT THU AUG 21 2003

MAIN FCST CONCERN WITH THIS UPDATE IS THUNDERSTORM AND SEVERE
WEATHER POTENTIAL THIS AFTERNOON AS COLD FRONT SWEEPS THRU THE
AREA.

WATER VAPOR IMAGERY AND RUC/ETA SHOWING A TROUGH OVER CENTRAL
CANADA...WITH A SERIES OF SHORTWAVES RACING TROUGH THE BASE OF THIS
TROUGH. THESE SHORTWAVES ARE PRODUCED SEVERE THUNDERSTORMS AS THEY
MOVED THROUGH THE FORECAST AREA THIS MORNING. A MORE INTENSE
SHORTWAVE IS MOVING INTO THE WESTERN U.P. A COLD FRONT IS PUSHING
INTO CENTRAL U.P. TRIGGERING MORE STORMS. LOW LEVEL MOISTURE
INDICATED BY SURFACE DEW POINT AROUND 70F AND A 850MB THETA-E RIDGE
IS FEEDING THESE STORMS.

THE CENTER OF SHORTWAVE WILL MOVE TO NEWBERRY BY 21Z THIS AFTERNOON
AS A LITTLE STRONGER SHORTWAVE MOVES THROUGH CENTRAL ONTARIO. THE
COLD FRONT WILL SLIDE ACROSS NORTHERN LAKE MICHIGAN AND BE OVER
NORTHERN LOWER MICHIGAN. THE THETA-E RIDGE AND HIGH SURFACE DEW
POINT WILL ALSO BE OVER LOWER MICHIGAN. THE SURFACE RIDGE WILL
EXPAND FROM THE DAKOTAS INTO FORECAST AREA. SURFACE DEW POINT WILL
LOWER OVER THE FORECAST AREA THIS AFTERNOON AS DRIER AIR ADVECTS
INTO THE AREA. FORECAST SOUNDING SHOWING COLD AIR ADVECTING BEHIND
THE FRONT SET UP A CAP ABOVE 800MB OVER THE WEST PART OF THE
FORECAST AREA THIS AFTERNOON WHICH LIMIT THE POTENTIAL OF
THUNDERSTORMS. CONDITIONS WILL REMAIN OVER THE SOUTHERN U.P. AND FAR
EAST THROUGH 18Z. BY 21Z THIS INSTABILITY WILL MOVE INTO LOWER
MICHIGAN. Q-VECTOR DIVERGENCE WILL INCREASE ACROSS THE AREA BY 21Z.
WINDS WILL SHIFT TO THE NORTHWEST FOLLOWING THE FRONT. TIGHTER
GRADIENTS WILL CAUSE AN INCREASE IN WINDS.

.MQT...NONE.

DLG

MIZ001>007-009>014-084-085-221200-

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE MARQUETTE MI
645 AM EDT THU AUG 21 2003

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS TODAY...

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

.DAY ONE...TODAY AND TONIGHT

SCATTERED THUNDERSTORMS THIS MORNING WILL BECOME NUMEROUS EARLY THIS
AFTERNOON OVER CENTRAL UPPER MICHIGAN...EAST OF A LINE FROM MUNISING
TO MENOMINEE. TO THE WEST OF THAT LINE...SCATTERED THUNDERSTORMS
WILL END BY MIDDAY AS A COLD FRONT PASSES. SOME OF THE STORMS TODAY
MAY BECOME SEVERE...MAINLY EAST OF A LINE FROM MUNISING TO
MENOMINEE. THE MAIN HAZARDS FROM ANY SEVERE STORMS WILL BE DAMAGING
WIND GUSTS GREATER THAN 60 MPH AND HAIL UP TO ONE INCH IN DIAMETER.
ALL THUNDERSTORMS PRODUCE DANGEROUS LIGHTNING.

.DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY

THERE IS A CHANCE OF THUNDERSTORMS ACROSS WEST AND CENTRAL UPPER
MICHIGAN MONDAY AND TUESDAY.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION MAY BE NEEDED TODAY.

ADDITIONAL WEATHER INFORMATION MAY BE OBTAINED AT THE FOLLOWING URL:

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

ROLFSON

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE MARQUETTE MI
1119 AM EDT THU AUG 21 2003

TIME(EDT)  .....CITY LOCATION.....STATE   ...EVENT/REMARKS...
           ....COUNTY LOCATION....

0916 AM    22 N NEWBERRY             MI   WIND DAMAGE
08/21/03   LUCE                           TRAVEL TRAILERS AND
                                          NUMEROUS TREES BLOWN OVER
                                          AT MUSKALLONGE STATE PARK

PETRO

MIZ007-014-085-212300-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE MARQUETTE MI
146 PM EDT THU AUG 21 2003

THE STORM PREDICTION CENTER HAS ISSUED A TORNADO WATCH FOR PORTIONS
OF UPPER MICHIGAN EFFECTIVE UNTIL 700 PM EDT.

THIS WATCH INCLUDES THE FOLLOWING COUNTIES...
  LUCE...SCHOOLCRAFT...

THIS INCLUDES THE FOLLOWING LOCATIONS...
  SENEY...NEWBERRY...MANISTIQUE...

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.

JKL

WWW.CRH.NOAA.GOV/MQT/