Heat in Michigan, June 28, 2002

SOUTHEAST MICHIGAN AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
250 PM EDT FRI JUN 28 2002

12Z RAOBS/WATER VAPOR LOOPS SHOW UPPER HIGH OVER THE CENTRAL
CONUS...BETWEEN TROUGHS OVER NEW ENGLAND AND OFF THE WEST COAST.
SURFACE ANALYSIS SHOWS A GENERAL HIGH OVER THE EASTERN CONUS...BUT
WITH A WEAK TROUGH OVER UPPER MICHIGAN AND THE OHIO VALLEY...PRETTY
MUCH A WEAK GRADIENT OVER THE REGION. EASTERN TROUGH WILL CUT-OFF
JUST OFF NEW ENGLAND...SETTING UP ANOTHER OMEGA BLOCK AND BRINGING A
RETURN TO HOT AND HUMID CONDITIONS FOR SOUTHEAST MICHIGAN BY EARLY
NEXT WEEK.

DRY AIRMASS CURRENTLY OVER THE CWA...WITH THE FEW CU THAT DEVELOPED
BEGINNING TO MIX OUT. LIGHT WINDS WITH THE WEAK GRADIENT FOR
TONIGHT. PATCHY FOG MAY DEVELOP IN LOW-LYING AREAS...BUT SHOULD NOT
BE MUCH OF A CONCERN WITH CONDENSATION PRESSURE DEFICITS STILL ABOVE
30MBS. WITH LITTLE CHANGE IN THE AIRMASS...LOWS TONIGHT LOOK TO BE
SIMILAR TO LAST NIGHT.

FOR SATURDAY...FORECAST PROFILES SHOW EVEN A BIT LESS LOW-LEVEL
MOISTURE..FURTHER LIMITING THE LIMITED CU DEVELOPMENT FROM TODAY.
SOME ADDITIONAL CIRRUS LOOKS TO SPREAD IN FROM THE NORTHWEST...
GIVING JUST A MOSTLY SUNNY DAY. SIMILAR STORY AGAIN FOR SATURDAY
NIGHT. A BIT MORE OF A GRADIENT FLOW FROM THE SOUTH/SOUTHEAST. CPDS
DOWN TO 20-30MBS /LOWEST ACROSS THE SOUTHERN CWA WITH MORE OF AN
EASTERLY FLOW OFF LAKE ERIE/ WITH ONLY LIGHT MVFR FOG POSSIBLE...NOT
THAT MUCH OF A CONCERN.

MORE OF A SOUTHWESTERLY GRADIENT SWINGS IN FOR SUNDAY...BUT STILL
PRETTY LIGHT. 950MB WINDS JUST UP TO 10KTS FOR LAKE BREEZE
POTENTIAL. MOISTURE INCREASES AS WELL WITH DEWPOINTS CLIMBING INTO
THE MID/UPPER 60S. MORE CU FOR THE DAY WITH MOISTURE AND WILL
MENTION PARTLY SUNNY SKIES IN THE AFTERNOON. STILL A DECENT CAP
DEPICTED AROUND 600MB /+3C AT 600MB/ ON ETA SOUNDINGS. WITH THIS AND
GENERALLY NEUTRAL SYNOPTIC FORCING AND LACK OF BOUNDARIES SAVE FOR
LAKE BREEZES...CONVECTIVE THREAT SHOULD BE MINIMAL.

ENERGY MOVING ONSHORE OVER THE PACIFIC NORTHWEST WILL HELP PROPEL A
FRONT FROM THE PLAINS TOWARD THE GREAT LAKES...WITH ETA/AVN IN
AGREEMENT WITH THE FRONT TO WESTERN LAKE SUPERIOR BY SUNDAY EVENING.
MAIN ENERGY/UPPER FORCING IS DEFLECTED NORTHEAST INTO CANADA...WITH
THE TAIL END OF THE FRONT WEAKENING OVER THE REGION AND IT
ENCOUNTERS THE HIGH. DESPITE NEUTRAL LIFT AND VERY MINIMAL /IF ANY/
LOW-LEVEL CONVERGENCE OVER LOWER MICHIGAN...AVN STILL TRIES TO PRINT
OUT A FEW TENTHS OF AN INCH OF QPF. WITH THE LACK OF SYNOPTIC
SUPPORT WILL LEAN TOWARD DRY CONDITIONS...WHICH IS SUPPORTED BY THE
ETA-EXTENSION. 12Z AVN LOOKS AS THOUGH IT DEVELOPS A CONVECTIVE
COMPLEX OVER NORTHERN LAKES MONDAY...AND DROPS IT THROUGH THE THUMB
TO LAKE ERIE MONDAY NIGHT. THIS IS A CHANGE FROM THE 00Z RUN...WHICH
WAS DRY OTHER THAN LIGHT QPF MONDAY AFTERNOON. 00Z CANADIAN SUPPORTS
AN EXTRAPOLATION OF THE ETA-EXTENSION...AND WILL HOLD ON TO THE DRY
FORECAST.

ANOTHER FRONT/WAVE DEVELOPS OVER THE NORTHERN PLAINS ON WEDNESDAY...
AND TRIES TO MAKE MORE HEADWAY ACROSS THE GREAT LAKES ON THURSDAY
TRAILING FROM A STRONGER SURFACE LOW THAT TRACKS INTO NORTHERN
QUEBEC. 00Z/28 AVN BRINGS MORE OF A FEATURE ACROSS THE CWA THAN THE
00Z/27 RUN...WITH THE 12Z/27 ECMWF ALSO DROPPING A WEAK SURFACE
TROUGH ACROSS THE STATE. CANADIAN ENSEMBLES/MEAN ALSO HINT AT A
WEAKNESS IN THE PRESSURE GRADIENT. MAIN ENERGY/LIFT STILL IS FOCUSED
NORTH OF THE CWA...AND WITH THE CHANGE FROM THE PREVIOUS RUN WILL
LEAVE THURSDAY DRY. UPSTREAM A MORE VIGOROUS SYSTEM MOVES ONSHORE IN
THE PACIFIC NORTHWEST ON THURSDAY...REAMPLIFYING THE RIDGE OVER THE
CENTRAL CONUS WITH JET/TROUGH DROPPING INTO THE EASTERN GREAT
LAKES/NEW ENGLAND FOR FRIDAY. STRONG SURFACE HIGH OVER OVER NORTHERN
ONTARIO TRIES TO EDGE INTO THE GREAT LAKES...BRINGING BRIEFLY COOLER
AND DRIER AIR TO THE REGION FOR FRIDAY.

.DTX...NONE.

BRAVENDER