Severe Thunderstorm Warning 44, NWS Marquette, MI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
400 PM EDT THU AUG 31 2000

12Z RAOBS/LATEST WV LOOP SHOW A CONFLUENT WSWLY INTO THE NW GRT
LKS/SW ONTARIO ON TOP OF UPR RDG OVR THE E. SFC COLD FNT BEHIND LO
PRES MOVG THRU NRN ONTARIO MOVD THRU CMX-IWD BTWN 17Z-18Z. SFC FNT
APRNT AS FINE LINE OF 88D/VIS SAT PIX AND BTWN BARAGA AND BIG BAY AT
1915Z. ALTHOUGH SW LLVL WNDS HAVE BROUGHT TEMPS/DWPTS WELL INTO 80S/LO
70S ACRS CWA...12Z GRB SDNG INDICATES LOCAL ATMOSPHERE EXTREMELY
CAPPED AT H85 WITH UPR DVGC ASSOCIATED WITH RRQ OF UPR JET ACRS SRN
HUDSON BAY TOO FAR TO THE N. LATEST RUC/GOES DERIVED SDNGS SUG
CONVECTIVE TEMP IN THE 90S...A BIT OUT OF REACH DESPITE OPPRESSIVE
HEAT AND HUMIDITY OVR CWA. A FEW BNDRYS FM PRIOR CNVCTN THAT WENT
THRU WRN LK SUP EARLIER THIS MRNG HAVE DONE LTL BUT INCRS SC IN LLVL
CNVGC AHD OF THEM. SHRTWV NOTED ON WV LOOP RIDING NNEWD THRU MN IS
CAUSING A FEW LTG STRIKES WELL BEHIND SFC FNT IN MN ATTM...BUT TRACK
OF SHRTWV APPEARS SO FAR TO THE W THAT CWA LIKELY EXPERIENCING
SUBSIDENCE ON ACYC SIDE. THIS SHRTWV APRCHG UPR CONFLUENT ZN. AT THE
SFC BEHIND COLD FNT...TEMPS FALL OFF SHARPLY WITH CONSIDERABLE LO
CLD LINGERING WELL BEHIND SHALLOW FNT. ANOTHER SHRTWV NOTED ON WV
LOOP OVR SE CO. THIS SYS APPEARS STRGR THAN 12Z MODELS ANALYZD.

MAIN FCST CONCERN TNGT IS SHRA/TSRA POTENTIAL. XPCT SFC FNT TO SLIDE
STEADILY SEWD THIS EVNG. ALTHOUGH NO SHRA/TSRA EVIDENT ATTM...THINK
SHRTWV IN MN MAY INCRS UPR DVGC ENUF OVR BNDRY BEFORE IT SHEARS OUT
TO THE N FOR AT LEAST SOME SCT SHRA/TSRA TO DVLP ALG BNDRY AND
ENHANCED LLVL CNVGC AS IT SINKS THRU SE ZNS THIS EVNG. WITH PW ARND
1.5" AT MPX THIS MRNG AND UPR WNDS NRLY PARALLEL TO SFC BNDRY...HAVE
CONTD MENTION OF LOCALLY HVY RA ASSOCIATED WITH CNVTN.
UNIDIRECTIONAL WND PROFILE ALSO SUGS GUSTY WNDS PSBL WITH TSRA...BUT
HI WBZ NR 12K-13K SUGS HAIL SHUD NOT BE A PROBLEM. SINCE MODELS
APPEAR TO UNDERDO SHRTWV EMERGING FM SW THIS AFTN...HAVE HEDGED
TOWARD AVN FCST OF MORE UPR DVGC/PCPN DVLG LATE TNGT AS THIS SYS
RIDES NE TO REINVIGORATE WAVE ALG FNT. SO POPS GENERALLY HIER THAN
MOS GUIDANCE AND CATEGORICAL ACRS SE WHERE BNDRY WL BE OVHD AT SAME
TIME UPR DVGC INCRSES. TSRA STILL PSBL OVR FAR S LATE TNGT INTO FRI
WITH AXIS OF SI ARND -4. HAVE LWRD MIN TEMPS FOR TNGT A BIT CLOSER
TO MOS GUIDANCE PER LO TEMPS LAST NGT BEHIND BNDRY AND SHARP PRES
RISES/APRNT CAD ACRS SW ONTARIO TDAY AS UPR CONFLUENCE STRENGTHENS
HI PRES TO N. ALSO XPCT LOTS OF FOG OVR UPSLOPE AREAS FM IWD-CMX-MQT
AS NELY FLOW MOISTENED OVR LK SUP RAMS UP HIER TERRAIN.

AVN SHOWS UPR DVGC/H100-5 MEAN RH GRDLY DIMINISHING TMRW...SO ENDED
PCPN NW-SE. BUT XPCT LOTS OF LO CLD/FOG TO LINGER AND KEEP TEMPS FM
RISING MUCH AT ALL IN ENELY FLOW ON SRN FLANK OF HI PRES IN ONTARIO.
WITH TEMPS UP TO 30 DEGREES LWR THAN TDAY... HIGHLIGHTED MUCH COOLER
FOR FRI PD.

MODELS SHOW UPR RDG PERSISTING OVR NRLY STNRY BNDRY FRI NGT/SAT WITH
GENERAL H7-3 QVECTOR DVGC. THINK FOG LIKELY AGAIN FRI NGT WITH
SHALLOW COOL AIRMASS...ESPECIALLY IN UPSLOPE AREAS OFF LK SUP. GIVEN
FCST END OF LLVL CAD AND SHALLOW NATURE OF COOL AIRMASS...MIN TEMPS
GENERALLY ABV MOS FOR FRI NGT. FLOW PROGGED TO BCM MORE SELY ON SAT
WITH CONTD SUBSIDENCE...SO XPCT INCRS IN SUNSHINE AS DIURNAL TREND
LIFTS LO CLD. TEMPS NR MOS.

EXTENDED MODELS ALL SHOW A MEAN TROF REMAINING OVR THE W CST INTO
NXT WEEK WITH A RDG AXIS PERSISTING FM THE WRN GRT LKS INTO THE
PLAINS UPWIND OF TROFFINESS IN ERN CAN. QUITE A BIT OF DISAGREEMENT
ON THE AMPLITUDE OF THE ERN CAN TROF/STRENGTH OF HUDSON BAY HI PRES
UNDER THE RDG AND HOW AGGRESSIVE DRY AIR FM THE N ASSOCIATED WITH
THIS HI WL PUSH QUASI-STNRY BNDRY OVR THE GRT LKS TO THE S. HAVE
DISREGARDED ECMWF SOLN OF DVLPG DEEP LO PRES OVR GRT LKS ON SUN
UNDER UPR CONFLUENCE IN MEAN RDG POSITION...BUT DO BELIEVE THERE WL
BE A WAVE ON THE FNT TO THE S ON SUN THAT WL INTRODUCE THE DRIER AIR
TO THE N INTO THE NW GRT LKS IN MON-TUE TIMEFRAME. NMRS CANADIAN/MRF
ENSEMBLE MEMBERS SHOW A SOLN SIMILAR TO THE UKMET WITH THE CNTRL CAN
RDG GAINING SOME AMPLITUDE AND INTRODUCING DRIER AIR WHILE HUDSON
BAY HI PRES INTENSIFIES. ALSO FEEL THIS FCST CONSISTENT WITH
DEEPENING TROF ALG THE W CST. SHRA CHCS WL INCRS DURG MID/LATE WEEK
AS NXT SHRTWV DIGGING INTO MEAN W CST TROF KICKS PREVIOUS SHRTWV TO
THE NE...WITH SLY FLOW AHD OF SYS OVRRNG HI PRES/DRIER AIR IN PLACE.
BUT A NUMBER OF MRF ENSEMBLES SHOW CONTD HIER AMPLITUDE TROF INTO
NEW ENGLAND...SUGING SFC HI PRES/DRY AIR WL BE SLOW TO YIELD AND
KEEP ERN ZNS DRIER. TEMPS WL AVG ABV NORMAL THRU PD UNDER MEAN RDG 
WITH A COOL NGT OR TWO EARLY NXT WEEK.

COORINATED WITH APX.

.MQT...NONE.

KC

MIZ004>006-010>014-010300-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE MARQUETTE MI
555 PM EDT THU AUG 31 2000

THE STORM PREDICTION CENTER HAS ISSUED A SEVERE THUNDERSTORM WATCH
FOR PORTIONS OF UPPER MICHIGAN EFFECTIVE UNTIL 11 PM EDT FRIDAY
MORNING(1000 PM CDT THURSDAY EVENING). THIS WATCH INCLUDES THE
FOLLOWING COUNTIES

IN WEST AND CENTRAL UPPER MICHIGAN

BARAGA...MARQUETTE...IRON...DICKINSON...MENOMINEE...DELTA...ALGER...
AND SCHOOLCRAFT COUNTIES.

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

A SEVERE THUNDERSTORM WATCH MEANS THAT CONDITIONS ARE FAVORABLE FOR
THE DEVELOPMENT OF SEVERE THUNDERSTORMS IN AND NEAR THE WATCH AREA.
REMEMBER...SEVERE THUNDERSTORMS ARE CAPABLE OF WIND GUSTS OF AT LEAST
60 MPH AND/OR HAIL THREE-QUARTERS OF AN INCH. IF YOU LIVE IN OR NEAR
THE WATCH AREA...YOU SHOULD REMAIN ALERT TO RAPIDLY CHANGING WEATHER
CONDITIONS. STAY T%UNED TO NOAA WEATHER RADIO OR LOCAL TELEVISION OR
RADIO STATIONS FOR FURTHER UPDATES AND POSSIBLE WARNINGS.

JLA

NNNN

MIZ004>006-010>014-010300-

SPECIAL WEATHER STATEMENT...CORRECTION
NATIONAL WEATHER SERVICE MARQUETTE MI
600 PM EDT THU AUG 31 2000

CORRECTED EXPIRATION TIME

THE STORM PREDICTION CENTER HAS ISSUED A SEVERE THUNDERSTORM WATCH
FOR PORTIONS OF UPPER MICHIGAN EFFECTIVE UNTIL 11 PM EDT SATURDAY
MORNING (1000 PM CDT THURSDAY EVENING). THIS WATCH INCLUDES THE
FOLLOWING COUNTIES

IN WEST AND CENTRAL UPPER MICHIGAN

BARAGA...MARQUETTE...IRON...DICKINSON...MENOMINEE...DELTA...ALGER...
AND SCHOOLCRAFT COUNTIES.

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

A SEVERE THUNDERSTORM WATCH MEANS THAT CONDITIONS ARE FAVORABLE FOR
THE DEVELOPMENT OF SEVERE THUNDERSTORMS IN AND NEAR THE WATCH AREA.
REMEMBER...SEVERE THUNDERSTORMS ARE CAPABLE OF WIND GUSTS OF AT LEAST
60 MPH AND/OR HAIL THREE-QUARTERS OF AN INCH. 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.

JLA

NNNN

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE MARQUETTE MI
737 PM EDT THU AUG 31 2000

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

0710 PM    SAGOLA                    MI   1 INCH HAIL
08/31/00   DICKINSON                      HAIL DURATION FOR 10 TO 15
                                          MINUTES.

AJ/JP

N