FXUS63 KDTX 261451
AFDDTX

SOUTHEAST MICHIGAN AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
1051 AM EDT MON MAY 26 2003

PERSISTENT UPPER LEVEL LOW CAN BE SEEN JUST EAST OF GEORGIAN BAY ON 
ALL THE SATELLITE DATA. THE 12Z UPPER AIR OBS...CURRENT SURFACE OBS 
AND THE LATEST VISIBLE LOOP INDICATES THAT PLENTY OF MOISTURE IN THE 
LOW LEVELS CONTINUE TO WRAP AROUND THE UPPER LOW AND INTO SOUTHEAST 
MICHIGAN. WITH THE 12Z KDTX SOUNDING SHOWING NEAR SATURATED 
CONDITIONS IN THE 750-900MB LAYER...DIURNAL CU SHOULD BE QUITE 
WIDESPREAD THIS AFTERNOON. THE LATEST VISIBLE IMAGES ARE BEGINNING 
TO SHOW THIS MORNINGS BREAKS QUICKLY FILLING IN WITH CU. FOR THE 
MOST PART...AFTERNOON CU FIELD WILL REMAIN BROKEN. DIURNAL MIXING 
SHOULD HOWEVER BEGIN TO ALLOW MORE SUNSHINE BY LATE AFTERNOON. WITH 
THIS SAID AND WITH THE LATEST VISIBLE IMAGE STILL SHOWING 
CONSIDERABLY BREAKS IN THE CLOUDS...I WILL CONTINUE WITH AN 
OPTIMISTIC PARTLY SUNNY FORECAST. EXPECT VFR CONDITIONS WITH CU 
FIELD THIS AFTERNOON. THE EXCEPTION WILL BE ACROSS THE SAGINAW 
VALLEY AND THUMB WHERE A STRATUS DECK OFF OF LAKE HURON SHOULD 
MAINTAIN LOCALLY LOWER CIGS FOR THE NEXT 2 TO 3 HOURS...POSSIBLY 
LONGER OVER THE THUMB.

UPDATED ZFPDTX AND GRIDDED FORECAST HAVE ALREADY BEEN ISSUED. I 
ADDED A MENTION OF A SLIGHT CHANCE OF AFTERNOON SHOWERS ACROSS THE 
ENTIRE FORECAST AREA GIVEN THE LATEST RUC AND MESO ETA SOUNDINGS 
SHOWING STEEP SFC TO 850MB LAPSE RATES WITH CAPE AROUND 100 J/KG BY 
LATE AFTERNOON. I ALSO LOWERED TEMPS ACROSS THE THUMB BASED ON 
CURRENT READINGS. PERSISTENT LAKE STRATUS AND NORTHEAST WINDS OFF 
LAKE HURON WILL HOLD TEMPS DOWN SEVERAL DEGREES FROM LOCATIONS 
FARTHER INLAND. 

CONSIDINE

..............PREVIOUSLY ISSUED AREA FORECAST DISCUSSION...........  

...PERIODIC SHRA/TSRA CHCS BECOMING MAIN CHALLENGE...

A VERY STAGNANT WX PATTERN WILL BE SHIFTING INTO AN ACTIVE ONE THIS 
WEEK AND MAYBE BACK TO STAGNATION NEXT WEEKEND? 00Z UAA SHOWED UPPER
LOW NOW A FAR DISTANCE EAST OF CWFA...BUT MODELS STILL WOBBLE IT BACK
THIS WAY FOR TUE/WED. THEREAFTER A SERIES OF DISTURBANCES RACE INTO 
THE AREA ON NW FLOW FROM THE NRN PACIFIC...THE FIRST OF WHICH IS NOW
PROGGED INTO THE AREA WED NIGHT/THU AM...A BIT FASTER. THIS STILL
KICKS THE CURRENT UPPER LOW OUT OF AREA...BUT REALLY DOESN/T CHANGE
THE BLOCKING PATTERN APPRECIABLY...SAVE A FEW DAYS LATE THIS WEEK. 
RIDGE REMAINS ANCHORED OVER WRN CONUS AND TROFFING CONTINUES OFF THE 
WEST COAST.

WILL CHANGE VERY LITTLE IN THIS FORECAST. FOR THE FIRST FIVE DAYS. 
NOT MUCH HAS CHANGED IN MODEL PROGS SO ONLY MINOR TWEAKS NEEDED. 
THEREAFTER...THE BUSINESS OF THE BLOCKING PATTERN MORE OR LESS 
HOLDING BECOMES AN ISSUE. AFTER SVRL NW FLOW WAVES RACE THRU 
AREA...GFS NOW DROPS A BIG CHUNK OF COOL AIR DOWN FROM CANADA AS 
RATHER DEEP UPPER LOW DEVELOPS OVER THE LAKES REGION NEXT WEEKEND
INTO EARLY NEXT WEEK. CMC AND UKMET SUPPORT THIS GENERAL IDEA...BUT 
ARE NOT QUITE AS BULLISH WITH DROPPING HGHTS THAT FAR SOUTH INTO THE 
REGION.
 
GIVEN THESE ARE DAYS 6/7...NOT WILLING TO BITE HOOK/LINE/SINKER...BUT
WILL TREND SUNDAY COOLER. THIS WOULD BE A RATHER UNFORTUNATE DVLPMNT
IF THINGS SHAPE UP IN THIS GENERAL WAY...EXTENDING AN ALREADY COOL/
DAMP SPRING INTO JUNE.

AGAIN...NOT MUCH CHANGE TO GOING FORECAST W/ TEMPS PUSHING 70 TODAY
THEN DROPPING BACK 5 OR SO DEGREES ON TUESDAY WITH UPPER LOW WOBBLE
THEN EDGING BACK UP TO 70 THU AND INTO THE 70-75 RANGE FRI/SAT. BEST
SHOTS AT PRECIP WILL BE SOME SHRAS ON TUE W/ UPPER LOW...SCT SHRAS
AND TSRAS WED NIGHT/THU AND FRI NIGHT/SAT WITH NW FLOW WAVES. WE/LL
SEE HOW THINGS SHAPE UP AFTER THAT.

.DTX...NONE. 

$$

GURNEY

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