000
FXUS63 KDTX 020841
AFDDTX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
341 AM EST MON DEC 2 2013

.SHORT TERM...TODAY AND TONIGHT

WITH WEAK COLD FRONT NOW WELL SOUTH OF THE AREA AND HIGH PRESSURE
BUILDING INTO THE AREA...EXPECT A RATHER QUIET DAY. AIRMASS BEHIND
THE FRONT IS NOT ESPECIALLY COLD...SO TEMPERATURES WILL REBOUND INTO
THE MID 30S TO AROUND 40 FROM NORTH/SOUTH ACROSS THE REGION TODAY. A
WEAK MID-LEVEL WAVE WILL MOVE THROUGH THE REGION THIS MORNING WITH
NO ASSOCIATED PRECIPITATION. SUBSIDENCE IN ITS WAKE WILL ALSO ALLOW
FOR SOME BREAKS IN THE OVERCAST BY THIS AFTERNOON.

THE AFOREMENTIONED FRONT...NOW STALLED OVER THE CENTRAL/SOUTHERN
OHIO VALLEY...WILL BEGIN TO LIFT SLOWLY BACK NORTH INTO THE REGION
TONIGHT AS UPPER TROUGHING OVER THE NORTHEAST CONUS TRANSITIONS TO A
MORE ZONAL FLOW AS SHORTWAVE RIDGE TRANSLATES EAST INTO THE REGION.
THIS WILL BRING A CHANCE OF LIGHT RAIN AND/OR SNOW TO THE SOUTHERN
CWA...PARTICULARLY AFTER MIDNIGHT TONIGHT. HOWEVER...WITH DECENT
FORCING ALONG THIS BOUNDARY LIMITED TO AREAS WELL WEST/NORTHWEST OF
SOUTHEAST MICHIGAN...PRECIPITATION WILL NOT BE SIGNIFICANT (AND WILL
MAINTAIN THE 20/30% POPS CURRENTLY IN THE FORECAST). WILL EVEN TRIM
THE NORTHERN EDGE NOTABLY AS HIGH PRESSURE WILL BE SLOW TO SHIFT
EAST OF THE THUMB REGION.

&&

.LONG TERM...

THE UPPER LOW OVER THE PACIFIC NORTHWEST WILL UNDERGO SUBSTANTIAL
SHEARING OVER THE NEXT 48 HOURS BEFORE AN AMPLIFYING HIGH LATITUDE
SHORTWAVE DROPS OUT OF NORTHWEST CANADA AND KICKS THE ENERGY
NORTHEAST INTO THE GREAT LAKES DURING THE MID-WEEK PERIOD. DURING
THIS TIME, LOW AMPLITUDE ENERGY WILL SHED OFF OF THE WESTERN U.S.
LOW AND STREAM EAST WHILE THE LOW-LEVEL RESPONSE ACROSS THE PLAINS
RESULTS IN THE ENCROACHMENT OF A WARM FRONTAL FEATURE ON THE LOWER
PENINSULA BY TUESDAY OR TUESDAY AFTERNOON. THE MAJOR GLOBAL MODELS
REMAIN KEYED IN ON A PERIOD OF 290-300K LAYER ISENTROPIC ASCENT AS
THIS FEATURE LIFTS THROUGH THE AREA, SUPPORTING BLANKET CHANCE POPS
TUES AFTN INTO TUESDAY NIGHT WITH LIKELY POPS ACROSS THE SAGINAW
VALLEY WHERE H85-H7 LAYER AVERAGED SPECIFIC HUMIDITIES WILL BE WELL
IN EXCESS OF 4 G/KG.

A LULL IN ACTIVITY WILL ENSUE LATE TUESDAY NIGHT THROUGH THE FIRST
HALF OF WEDNESDAY AS THE AREA WILL BE ENTRENCHED WITHIN THE
DEVELOPING WARM SECTOR. SOUTHERLY FLOW WILL OVERSPREAD THE AREA AS
THE DEEPENING SURFACE LOW BEGINS ITS CLIMATOLOGICALLY COMMON TREK
FROM THE FRONT RANGE TO THE STRAITS. H85 TEMPS ARE PROGGED BY THE
ECMWF TO REACH 6-7C BY WED AFTN. OVERNIGHT LOWS TUESDAY NIGHT WILL
BE UNLIKELY TO FALL MUCH BELOW 40 DEGREES DUE TO ONGOING WARM
ADVECTION AND MAY EVEN BE ON THE RISE FOR MUCH OF THE NIGHT. CLOUDS
AND A STRONG INVERSION WILL BE MAJOR LIMITING FACTORS FOR HIGH
TEMPERATURES ON WEDNESDAY, BUT SURFACE WARM ADVECTION ALONE SEEMS
SUPPORTIVE OF TEMPERATURES AT LEAST IN THE UPPER 40S TO LOW 50S.

VIGOROUS LOW-LEVEL JET RESPONSE TO THE TUNE OF 45-50KTS AT 850MB
WILL THEN SUPPORT THE DEVELOPMENT OF WIDESPREAD SHOWERS IN ADVANCE
OF THE COLD FRONT FROM THE OHIO VALLEY AND ACROSS THE MIDWEST ON
WEDNESDAY, PROVIDING SUPPORT FOR THE BIGGEST CHANGE TO THE FORECAST
WHICH WAS TO INCREASE ALL AREAS TO HIGH CHANCE/BORDERLINE LIKELY
POPS FROM 18Z WED THROUGH 06Z THURS - THE TARGET PERIOD FOR FROPA.
MUCH COOLER AIR WILL FILTER IN FOR THURSDAY, BUT WITH ALL OF THE
MOISTURE EXPECTED TO BE PREFRONTAL, PROSPECTS FOR SNOW SHOWERS ARE
MINIMAL.

&&

.MARINE...

STRENGTHENING LOW PRESSURE WILL LIFT INTO THE NORTHERN GREAT LAKES
WEDNESDAY INTO WEDNESDAY NIGHT. THIS WILL SUPPORT THE DEVELOPMENT OF
A FRESH SOUTHEAST BREEZE TUESDAY AFTERNOON THROUGH MUCH OF WEDNESDAY
WITH STABLE CONDITIONS ACROSS THE WATERS PREVENTING MUCH IN THE WAY
OF GUSTS. WAVES WILL BEGIN STEADILY BUILDING ON TUESDAY WITH
SIGNIFICANT WAVE HEIGHTS FORECAST TO PEAK AT 7 TO 8 FEET OVER
CENTRAL LAKE HURON ON WEDNESDAY AFTERNOON. WESTERLY WINDS WILL GUST
TO 25 KNOTS OR HIGHER ON THURSDAY AS COLDER AIR SPREADS ACROSS THE
LAKES.

&&

.AVIATION...ISSUED 1153 PM EST SUN DEC 1 2013

//DISCUSSION...

STRIP OF LOW MVFR/IFR STRATUS BLANKETING PTK AND ON THE EDGE DTW
WILL BE A PREVALENT FEATURE THROUGH THE PRE-DAWN HOURS.  HOWEVER...
THERE IS EVIDENCE PER RECENT SATELLITE AND MODEL GUIDANCE THAT THE
SUB-3000 FT LAYER MAY UNDERGO A HIGHER DEGREE OF DRYING FROM THE
NORTH THROUGH THE COURSE OF THE NIGHT....WITH THE BETTER MOISTURE
FLUX OFF LAKE HURON CONFINED TO THE EAST.  THIS WOULD SUPPORT A
GRADUAL EROSION OF THIS DECK WITH TIME THROUGH THE MORNING HOURS.
A FEW POCKETS OF CLEARING SKY EMERGING NEAR THE OHIO BORDER COULD
POTENTIALLY BRING A STRONGER BR/FG ELEMENT IN DETROIT AND WILL
CONTINUE TO MONITOR.  SOME DEGREE OF INLAND PENETRATION OF LAKE
MOISTURE WITHIN LIGHT NORTH TO NORTHEAST FLOW WILL LIKELY KEEP SOME
FORM OF LOWER STRATUS OVER SOUTHEAST MICHIGAN WELL INTO MONDAY.

//DTW THRESHOLD THREATS...

* MEDIUM CONFIDENCE IN CIGS BELOW 5KFT THROUGH MONDAY AFTERNOON.

&&

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

&&

$$

SHORT TERM...DG
LONG TERM....JVC
MARINE.......JVC
AVIATION.....MR


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