Area Forecast Discussion
Issued by NWS Detroit/Pontiac, MI

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FXUS63 KDTX 271754
AFDDTX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
154 PM EDT MON OCT 27 2014


.AVIATION...

//DISCUSSION...

A WARM FRONT IS LIFTING THROUGH THE AREA THIS AFTERNOON WILL YEILD
MAINLY CIRRUS CLOUDS WITH GUSTY SOUTHWEST FLOW. DEEPER MOISTURE WILL
MOVE IN BEHIND THE FRONT AS THE MAIN SYSTEM OVER NE IOWA DRAWS
NEARER WHICH WILL BRING A RETURN OF LOW CLOUDS. SHOWERS...AND
POSSIBLY THUNDERSTORMS...WILL BEGIN EARLY TOMORROW MORNING AS THE
COLD FRONT APPROACHES FROM THE WEST. RAIN SHOULD BEGIN FOR MBS AND
FNT IN THE EARLY MORNING HOURS AROUND 08Z...BUT THE SLOW PROGRESSION
EASTWARD WILL KEEP THE DETROIT AREA TAFS DRY UNTIL CLOSER TO 14Z. AS
OF NOW INCLUDED MVFR CONDITIONS FOR THE SHOWERS UNTIL WE BETTER
CONFIDENCE IN COVERAGE CAN BE DETERMINED.

//DTW THRESHOLD THREATS...

* MEDIUM CONFIDENCE IN CEILINGS BELOW 5000 FT TUESDAY MORNING.

&&

.PREV DISCUSSION...ISSUED 316 AM EDT MON OCT 27 2014

SHORT TERM...TODAY AND TONIGHT

MID LEVEL RIDGING WILL TRACK EAST THROUGH THE CENTRAL GREAT LAKES
EARLY THIS MORNING...ENDING THE DRY TRANQUIL CONDITIONS AS A LOW
PRESSURE SYSTEM DEVELOPS OVER THE WESTERN GREAT LAKES TODAY. AS THE
MID LEVEL RIDGE TRACKS EAST...WARM AIR WILL ADVECT NORTH ON THE
BACKSIDE AS A SURFACE WARM FRONT SLOWLY LIFTS NORTH DURING THE DAY.
THERE WILL BE A CHANCE FOR SHOWERS AND THUNDERSTORMS TODAY AS THE
FRONT LIFTS NORTH...WITH THE BEST CHANCES LATER THIS MORNING AND
INTO THE EARLY AFTERNOON ACROSS THE NORTHERN CWA AS THE FRONT LIFTS
NORTH. CONFIDENCE IN THUNDERSTORMS IS STILL ON TRACK GIVEN THE WARM
UNSTABLE AIR AFFORDED BY THE WARM FRONT AND UPSTREAM DATA SHOWING
SEVERAL LIGHTNING STRIKES ACROSS THE WESTERN GREAT LAKES. ONCE THE
FRONT PUSHES NORTH IT WILL BE HARDER TO DEVELOP CONVECTION IN THE
CAPPED WARM SECTOR.  THE WARM SECTOR WILL BRING MUCH WARMER
TEMPERATURES TODAY...WITH HIGHS EXPECTED TO BE ABOUT 10 DEGREES
ABOVE NORMAL FOR THIS TIME OF THE YEAR.  HIGHS WILL RANGE FROM THE
LOWER TO MIDDLE 60S ACROSS THE NORTH...TO AROUND 70 NEAR THE OHIO
BORDER.

THE SURFACE LOW OUT TO THE WEST WILL CONTINUE TO DEVELOP TONIGHT AND
DEEPEN AS IT TRACKS NORTHEAST TOWARDS THE EASTERN UPPER
PENINSULA...PUSHING THE COLD FRONT OUT OVER WESTERN MICHIGAN LATE IN
THE OVERNIGHT HOURS. A SHORTWAVE SPEEDING OUT AHEAD OF THE COLD
FRONT AND MAIN MID LEVEL TROUGH WILL BRING THE CHANCE FOR SHOWERS
AND THUNDERSTORMS OVERNIGHT AS A POWERFUL 110+ KNOT UPPER LEVEL JET
NOSES INTO THE SOUTHWESTERN GREAT LAKES. WITH THE AREA STILL IN THE
WARM SECTOR OVERNIGHT LOWS WILL BE RELATIVELY WARM...GENERALLY
RANGING FROM 55 TO 60 DEGREES.

LONG TERM...

UPPER LEVEL TROUGH/ENERGY MOVING OUT OF THE NORTHERN ROCKIES
TODAY...WITH SOLID CYCLOGENSIS OCCURRING OVER THE WESTERN GREAT
LAKES TONIGHT...LIFTING NORTHEAST INTO ONTARIO TOMORROW. 850 MB
THETA-E RIDGE/INSTABILITY SEEN EXITING SOUTHEAST MICHIGAN BETWEEN 14-
17Z AS SURFACE COLD FRONT FOLLOWS SUITE. 00Z NAM NOT REALLY VERY
BULLISH WITH QPF...DESPITE WHAT LOOKS TO BE ADEQUATE MOISTURE PLUME
AND FORCING...AS PW VALUES COME JUST SHORT OF 1.5 INCHES...WITH
GOOD MID LEVEL LAPSE RATES (7+C FROM 700-500 MB). FORTUNATELY NO
SURFACE BASED INSTABILITY PRESENT...AS STABLE NEAR SURFACE LAYER AND
UNFAVORABLE MORNING TIMING EXPECTED TO KEEP THUNDERSTORMS AT BAY.
POST FRONTAL WINDS TUESDAY AFTERNOON WILL BE STRONG...AS 6 HR
RISE/PRESSURE COUPLET LOOKS TO BE 14 TO 15 MB...AND GUSTS OF 35 TO
40 MPH LOOK POSSIBLE TOWARD SAGINAW BAY...EMBEDDED IN THE BETTER LOW
LEVEL COLD ADVECTION AND CLOSER TO PARENT SURFACE LOW.

COLD CYCLONIC FLOW TUESDAY NIGHT INTO WEDNESDAY WITH 850 MB TEMPS
FALLING BELOW ZERO SHOULD ASSURE PLENTY OF CLOUDS...WITH
ISOLATED-SCATTERED LAKE ENHANCED INSTABIILTY SHOWERS
POSSIBLE...ESPECIALLY IF THE 00Z EURO IS RIGHT WITH SHORTWAVE
WORKING THROUGH SOUTHERN LOWER MICHIGAN DURING THE DAY.
925 MB TEMPS AT OR SLIGHTLY ABOVE +4 C POINTS TO MAXES HOLDING
AROUND 50 DEGREES...WITH THE POTENTIAL TO BE SLIGHTLY COLDER IF
SHOWERS ARE MORE PREVALENT.

ANY MODERATION OF THE LOW LEVEL AIRMASS ON THURSDAY WILL BE SHORT
LIVED...AS MEDIUM RANGE MODELS (GFS/EURO/CANADIAN) REMAIN
FAIRLY CONSISTENT DRIVING AN ARCTIC FRONT THROUGH THE CENTRAL GREAT
LAKES ON FRIDAY...WITH 850 MB TEMPS PLUMMETING TO -10 C (PER
EURO)...MORE THAN COLD ENOUGH TO SUPPORT SNOW SHOWERS. THE
00Z CANADIAN SOLUTION OFFERS UP MORE OF A GLANCING BLOW WITH
THE COLD AIR...BUT STILL SHOWING 1000-850 MB THICKNESSES HOVERING
AROUND 1300 M.

MARINE...

HIGH PRESSURE PRODUCING RELATIVELY CALM CONDITIONS THIS MORNING WILL
PUSH EAST...ALLOWING SOUTHERLY FLOW TO INCREASE THROUGH TUESDAY...IN
ADVANCE OF AN APPROACHING COLD FRONT. THIS FRONT WILL TRIGGER
SHOWERS AND EMBEDDED THUNDERSTORMS.  WINDS WILL VEER TO THE
WEST/SOUTHWEST WITH THE PASSAGE OF THIS FRONT TUESDAY AFTERNOON INTO
TUESDAY NIGHT. WINDS GUSTING TO 25 KNOTS OR SLIGHTLY BETTER WILL BE
COMMON OVER LAKE HURON AS COLDER AIR FILTERS INTO THE CENTRAL GREAT
LAKES. EVEN COLDER AIR IS FORECASTED TO ARRIVE ON FRIDAY BEHIND AN
ARCTIC FRONT...AND SUBSEQUENTLY WINDS WILL LIKELY BE STRONGER AS
WELL...WITH GUSTS TO AT LEAST 30 KNOTS OVER THE OPEN WATER OF LAKE
HURON.

&&

.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MICHIGAN WATERS OF LAKE ERIE...NONE.
&&

$$

AVIATION.....DRK
SHORT TERM...KURIMSKI
LONG TERM....SF
MARINE.......SF


YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).



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