Area Forecast Discussion
Issued by NWS Detroit/Pontiac, MI

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FXUS63 KDTX 221648
AFDDTX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
1248 PM EDT TUE APR 22 2014

.AVIATION...

//DISCUSSION...

MVFR STRATOCU WILL BE WIDESPREAD OVER SE MICHIGAN BUT WILL MIX INTO
LOW END VFR CEILING DURING THE AFTERNOON. THIS WILL OCCUR AS MORE
COLD AIR IS CARRIED INTO THE REGION ON NORTHWEST WIND GUSTING TO
AROUND 25 KNOTS. THE WELL MIXED CONDITIONS WILL LAST FOR A FEW HOURS
AFTER SUNSET BEFORE CEILING FILLS IN AND LOWERS BACK INTO MVFR.
AFTERNOON OBSERVATIONS OVER THE NORTHERN GREAT LAKES SUPPORT MODEL
IMPLICATIONS THAT STRATUS WILL HOLD WITHIN THE COLD LOW LEVEL
THERMAL TROUGH DURING THE NIGHT. THERE IS SOME UNCERTAINTY
INTRODUCED TO THE CLOUD FORECAST BY THE DRYING INFLUENCE OF A MORE
NEUTRAL NW FLOW EVOLVING WITH TIME...BUT OBSERVATIONS ALSO SUPPORT
MODEL SOLUTIONS THAT SUGGEST IT WILL TAKE UNTIL WEDNESDAY MORNING
BEFORE DRY BOUNDARY LAYER AIR NORTH OF LAKE SUPERIOR CAN MOVE INTO
SE MICHIGAN AND SCOUR OUT THE LOW CLOUDS.

//DTW THRESHOLD THREATS...

* MODERATE CONFIDENCE IN CEILING BELOW 5000 FEET DURING MID
AFTERNOON THROUGH TONIGHT.

* HIGH CONFIDENCE IN WIND GUSTING AROUND 25 KNOTS FROM 310 DEGREES
THROUGH MID EVENING.

&&

.PREV DISCUSSION...ISSUED 341 AM EDT TUE APR 22 2014

SHORT TERM...TODAY AND TONIGHT

SHOWERS WILL END DURING THE PRE-DAWN HOURS AS A VIGOROUS SHORTWAVE
AMPLIFIES ACROSS THE AREA AND DRIVES A COLD FRONT SOUTHEAST THROUGH
THE CENTRAL GREAT LAKES. NOTABLY COOLER CONDITIONS CAN BE EXPECTED
IN THE WAKE OF THIS COLD FRONT AS TEMPERATURES HOVER GENERALLY IN
THE 50-55 DEGREE RANGE IN MOST LOCATIONS DURING THE DAY. NORTHWEST
WINDS WILL ALSO BE RATHER GUSTY WITHIN COLD AIR ADVECTION PATTERN.
SO...A DIURNAL CUMULUS/STRATO-CU FILL IN OVER THE AREA AS THE UPPER
LEVEL COLD POOL ASSOCIATED WITH THE AFOREMENTIONED SHORTWAVE MOVES
ACROSS THE AREA...CONDITIONS WILL BECOME RATHER COOL BY MIDDAY AS
ANY PEEKS ARE THE SUN BECOME FEW AND FAR BETWEEN. THIS DIURNAL CLOUD
DEVELOPMENT WILL ALSO LEAD TO A CHANCE OF ISOLATED/SCATTERED SHOWERS
OVER THE THUMB AS LOW LEVEL MOISTURE FIELD IS ENHANCED BY NORTH TO
NORTHWEST FLOW FROM LAKE HURON.

CONDITIONS CALM SIGNIFICANTLY THIS EVENING INTO TONIGHT AS HIGH
PRESSURE BUILDS TOWARDS THE REGION. EXPECT CLEARING SKIES A LIGHT
NORTHWEST FLOW OF 5 MPH OR SO. THIS WILL LEAD TO RATHER DECENT
RADIATIONAL COOLING WITH TEMPERATURES FALL TO AROUND FREEZING IN
MANY AREAS. THE HEAT ISLAND WITHIN THE CORE OF METRO DETROIT WILL
MAINTAIN A FEW READING CLOSER TO 35 DEGREES WHILE SOME AREAS OVER
THE GENESEE/SAGINAW VALLEY...CLOSES TO THE APPROACHING HIGH...DROP
INTO THE UPPER 20S.

LONG TERM...WEDNESDAY THROUGH MONDAY

THE SHORTWAVE DIVING INTO THE EXITING TROUGH SHOULD BE THROUGH THE
AREA BY WEDNESDAY MORNING. THIS WILL OPEN THE DOOR FOR MID LEVEL
RIDGING TO BUILD INTO THE STATE THROUGH THE DAY. HEIGHTS WILL ONLY
SLOWLY RISE AS NW FLOW ALOFT LINGERS OVERHEAD. AT THE SFC A COOL
CANADIAN HIGH PRESSURE SYSTEM WILL CENTER ITSELF OVER THE GREAT
LAKES BY EARLY WEDNESDAY NIGHT. NORTHERLY FLOW WILL KEEP US BELOW
AVERAGE ONCE AGAIN BY 5-10 DEGREES AS 850MB TEMPS STAY BELOW 0C
THROUGH THE DAY. WINDS WILL SWITCH AROUND TO SOUTHERLY WEDNESDAY
NIGHT AS THE HIGH DRIFTS EAST. THIS WILL ALLOW SOME WARMING TO THE
COLUMN DURING THAT TIME. CLOUDS WILL START TO FILL BACK IN FROM THE
SW OVERNIGHT AS A WARM FRONT DRAWS NEAR THE AREA OUT AHEAD OF THE
NEXT LOW PRESSURE SYSTEM THAT WILL TARGET MI. THE CLOUDS WILL KEEP
LOW TEMPERATURES FROM TANKING TOO MUCH FOR THOSE LOCATIONS CREATING
A RANGE FROM NEAR FREEZING FOR THE THUMB TO NEAR 40 ACROSS THE FAR
SOUTH.

THURSDAY WE WILL BE CLOSER TO NORMAL...AROUND 60 DEGREES...AS THE
WARM FRONT LIFTS THROUGH LATE IN THE DAY. THE SFC LOW ITSELF IS TIED
TO A SHORTWAVE LIFTING NE FROM THE SOUTHERN PLAINS. IT WILL PHASE
WITH A STRONGER NORTHERN STREAM WAVE SURGING ACROSS THE NORTHERN
TIER OF THE CONUS THURSDAY INTO FRIDAY. SO THE SFC LOW WILL LIFT NE
INTO THE AREA BEFORE FEELING THE STRONGER HEIGHT FALLS OVER NORTHERN
MI WHICH WILL STALL IT TEMPORARILY AS THE SYSTEM AS A WHOLE
REORGANIZES. THE LEADING LOW WILL BRING A COLD FRONT THROUGH SE MI
THURSDAY NIGHT AND FRIDAY MORNING. WE SHOULD SEE A BRIEF LULL IN THE
EARLY AFTERNOON BEFORE THE STRONGER COLD FRONT FROM THE SECOND LOW
SWEEPS THROUGH FRIDAY EVENING/NIGHT. THIS FRONT WILL USHER YET
ANOTHER COOL CANADIAN AIRMASS INTO THE REGION AS THE BROAD UPPER
LEVEL TROUGH CONSUMES THE GREAT LAKES SHUNTING THE MAIN BAROCLINIC
ZONE TO OUR SOUTH. 850MB TEMPS WILL FALL FROM AROUND +7C FRIDAY
MORNING TO NEAR -5C SATURDAY MORNING LEADING TO COOL HIGHS AROUND
50F WITH LOWS IN THE LOW/MID 30S INTO THE BEGINNING OF NEXT WEEK.

MARINE...

A PASSING COLD FRONT HAS OPENED THE DOOR FOR COLD NORTHWESTERLY FLOW
TO ONCE AGAIN SURGE INTO THE GREAT LAKES. THE INITIAL RESPONSE WILL
BE INCREASED NORTHWESTERLY FLOW BEFORE A SECONDARY TROUGH AXIS DROPS
THROUGH VEERING WINDS MORE NORTHERLY. WIND SPEEDS WILL INCREASE TO
AROUND 25 KNOTS TODAY WITH GUSTS POTENTIALLY REACHING 30 KNOTS FOR A
TIME. THIS WILL LEAD TO INCREASED WAVE HEIGHTS ALONG THE THUMB AND
WORKING DOWN THE LAKE HURON COASTLINE THIS AFTERNOON. DUE TO THE
COMBINATION OF ELEVATED WINDS AND WAVES SMALL CRAFT ADVISORIES HAVE
BEEN ISSUED FOR THOSE ZONES. THOUGH WINDS WILL TAPER OFF SOME
TONIGHT...CONTINUED NORTHERLY FLOW WILL KEEP WAVE HEIGHTS ELEVATED
THROUGH WEDNESDAY MORNING BEFORE THEY FINALLY SUBSIDE ENOUGH TO END
THE ADVISORY. HIGH PRESSURE WILL BRING IMPROVED CONDITIONS TO THE
REGION LATE WEDNESDAY INTO THURSDAY BEFORE THE NEXT SYSTEM ARRIVES
FRIDAY.

&&

.DTX WATCHES/WARNINGS/ADVISORIES...

MI...NONE.

LAKE HURON...
     SMALL CRAFT ADVISORY...OUTER SAGINAW BAY AND THE NEARSHORE WATERS
     FROM PORT AUSTIN TO HARBOR BEACH...UNTIL 10 AM WEDNESDAY.

     SMALL CRAFT ADVISORY...NEARSHORE WATERS FROM HARBOR BEACH TO PORT
     HURON...FROM 4 PM TUESDAY TO 10 AM WEDNESDAY.

LAKE ST CLAIR...NONE.

MI WATERS OF LAKE ERIE...NONE.

&&

$$

AVIATION.....BT
SHORT TERM...DG
LONG TERM....DRK
MARINE.......DRK


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AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).








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