FXUS63 KDTX 220723
AFDDTX

SOUTHEAST MICHIGAN AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
323 AM EDT SUN JUN 22 2003

HIGH PRESSURE TO REMAIN GOVERNING FACTOR IN THE WEATHER PATTERN OVER 
SE MICHIGAN TODAY AND MONDAY, WHITTLING THE FORECAST CHALLENGE DOWN 
TO TEMPS.

THE 00Z MODEL SOLUTIONS ARE IN GOOD AGREEMENT IN KEEPING THE SURFACE 
RIDGE AXIS UPON US OR JUST TO OUR WEST TODAY, WITH LITTLE OR NO 
TEMPERATURE OR MOISTURE ADVECTION IN THE LOW LEVELS. EXPECT MAX 
TEMPS IN THE LOWER TO MID 80S, A DEGREE OR TWO WARMER THAN 
YESTERDAY. THIS, ALONG WITH EXAMINATION OF FORECAST SOUNDINGS, 
SUGGESTS THE FWC/NGM GUIDANCE IS ABOUT A CATEGORY TOO HIGH. ALSO,  
THE NEARLY FLAT SURFACE PRESSURE GRADIENT WILL ALLOW ACTIVE LAKE 
BREEZE DEVELOPMENT AND KEEP READINGS COOLER NEAR THE SHORELINES.     

THE SURFACE RIDGE WILL TAKE MOST OF THE DAY TO MOVE EAST ON MONDAY 
AND GIVE US ONE MORE DAY OF LOWER HUMIDITY. UPSTREAM OBS AND 
FORECAST SOUNDINGS SUGGEST HIGH TEMPS ANOTHER CATEGORY HIGHER THAN 
TODAY. UPPER 80S WILL BE COMMON WITH A COUPLE OF 90S POSSIBLE, BUT 
THEY WILL BE ON THE UPPER END OF THE RANGE IN THE ABSENCE OF A 
STRONG SW SURFACE WIND. FLINT HAS A RELATIVELY LOW RECORD HIGH TEMP 
OF 91 FOR JUNE 23 WITH MBS AND DTW BOTH IN THE MID 90S.

MOISTURE RETURN RAMPS UP CONSIDERABLY ON TUESDAY BUT THERE REMAINS 
SOME TIMING DIFFERENCES BETWEEN THE ETA AND GFS. THE GFS IS MUCH 
FASTER MOVING THE 850 MB THETA-E RIDGE INTO THE AREA MONDAY NIGHT 
WHILE THE ETA HOLDS OFF UNTIL TUESDAY AFTERNOON. CONSIDERING THE 
SHAPE OF THE 500 MB RIDGE, THE GFS LOOKS LIKE IT HAS TOO MUCH OF A 
WESTERLY WIND COMPONENT AT 850 MB, WHICH IS SUPPORTED BY THE 12Z 
ETA-XX. ALWAYS A LITTLE WARY OF LOW LEVEL MOISTURE ADVECTION AT 
NIGHT BUT THE ETA TIMING STILL SUPPORTS CHANCE POPS ON TUESDAY FOR 
THE SAGINAW VALLEY RATHER THAN MONDAY NIGHT. THERE COULD BE SOME 
NOCTURNAL DEVELOPMENT TO OUR WEST MONDAY NIGHT BUT IT WILL TAKE 
UNTIL THE DAYTIME HOURS OF TUESDAY MORNING TO REACH OUR AREA. THE 
PATTERN DOES LOOK DRY IN TERMS OF MEAN RH AND A LITTLE CAPPED OFF IN 
THE 850 TO 700 MB LAYER. OUR GOING FORECAST LOOKS GOOD. 

HOT AND HUMID WEATHER WILL CONTINUE INTO WEDNESDAY WITH DEEP SW FLOW 
KEEPING THE COLD FRONT ADVANCING SLOWLY INTO THE WESTERN GREAT 
LAKES. FROPA LATE THURSDAY LOOKS REASONABLE BASED ON THE 00Z GFS 
BRINGING AN UPPER WAVE INTO THE MIDWEST.

.DTX...NONE.

$$

EXPERIMENTAL GRAPHICAL FORECASTS ARE AVAILABLE ONLINE AT  
HTTP://WWW.CRH.NOAA.GOV/DTX  (ALL LOWER CASE)

BT