Area Forecast Discussion
Issued by NWS Detroit/Pontiac, MI

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FXUS63 KDTX 271734
AFDDTX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
1234 PM EST TUE JAN 27 2015


.AVIATION...

PRIMARILY VFR CONDITIONS THROUGH THE TAF CYCLE AS AN AREA OF HIGH
PRESSURE SLIDES THROUGH THE REGION. THE ONE CONCERN FOR THIS
AFTERNOON IS MOISTURE ADVECTING INLAND OFF LAKE HURON LEADING TO
POCKETS OF MVFR LAKE EFFECT STRATO-CU. THE DRY AIR HAS MADE IT
DIFFICULT TO SUSTAIN THE CLOUDS TOO FAR INLAND BUT DID INCLUDE A
MVFR TEMPO GROUP FOR MBS AND FNT FOR A FEW HOURS TO ACCOUNT FOR
THICKER CLOUD COVER IN THAT AREA. AFTERNOON WINDS WILL DECREASE THIS
EVENING...BECOME LIGHT AND VARIABLE OVERNIGHT.

//DTW THRESHOLD PROBABILITIES...

* LOW FOR CEILING BELOW 5000 FT TODAY.

&&

.PREV DISCUSSION...ISSUED 253 AM EST TUE JAN 27 2015

SHORT TERM...TODAY AND TONIGHT

COLD...BUT QUIET...WEATHER WILL CONTINUE OVER THE AREA AS HIGH
PRESSURE SETTLES SOUTH INTO THE AREA ON BACKSIDE OF MAJOR STORM
LIFTING UP THE NORTHEAST COAST. INITIALLY...EXPECT PARTLY TO MOSTLY
CLOUDY SKIES TODAY AS BOTH STRATUS/STRATO-CU FROM LAKE HURON AND A
MID LEVEL DECK ASSOCIATED WITH A SHORTWAVE COMBINE TO BRING SOME
DEGREE OF CLOUDINESS TO A GOOD PORTION OF THE AREA. TEMPERATURES
WILL REMAIN BELOW AVERAGE AS HIGHS ONLY CLIMB INTO THE LOWER TO
MIDDLE 20S BY AFTERNOON.

AS THE AFOREMENTIONED HIGH SETTLE OVER AND THEN JUST SOUTH OF THE
AREA THIS EVENING INTO TONIGHT...SKIES WILL LARGELY CLEAR. THIS WILL
COMBINE WITH LIGHT WINDS ASSOCIATED WITH THE HIGH TO PRODUCE RATHER
DECENT RADIATIONAL COOLING. SO...EXPECT WIDESPREAD LOW TEMPERATURES
IN THE SINGLE DIGITS...SOME 8 TO 10 DEGREES BELOW AVERAGE FOR LATE
JANUARY.

LONG TERM...

SHORTWAVE ANCHORING NORTHERN SEGMENT OF THE EAST PAC TROUGH WILL
COME ONSHORE IN BRITISH COLUMBIA OVER THE NEXT 18 HOURS. THE BAJA
LOW HAS SIMTULTANEOUSLY BEGUN TO OPEN UP AND HELP ERODE THE RIDGE
POSITIONED OVER THE WESTERN UNITED STATES. THE SURFACE LOW ATTENDANT
TO THE LEAD SHORTWAVE WILL HELP ENHANCE DEVELOPING SOUTHEAST RETURN
FLOW ON WEDNESDAY, ALLOWING HIGHS TO WARM SEVERAL DEGREES OVER
TODAY. FORECAST SOUNDINGS ARE ONLY MARGINALLY SUPPORTIVE OF DIURNAL
STRATOCU DEVELOPMENT BENEATH THE STOUT DRY SUBSIDENT LAYER ALOFT, SO
ELECTED TO REMAIN CONSERVATIVE WITH CLOUD COVER ON WED. AFTERNOON
HIGHS SHOULD REACH CLOSE TO 30 DEGREES IN MOST SPOTS UNDER PARTLY
CLOUDY SKIES.

PRECIPITATION WILL BLOSSOM JUST UPSTREAM OF THE AREA WEDNESDAY NIGHT
INTO THURSDAY AS HEIGHT FALLS SPREAD INTO THE REGION AND ISENTROPIC
ASCENT SUPPORTED BY A STRENGTHENING LOW-LEVEL JET RAMPS UP. THE
GFS/GEM HAVE TRENDED TOWARD PRIOR ECMWF SOLUTIONS IN THAT THEIR MORE
AGGRESSIVE DEPICTIONS OF THE TRAILING SHORTWAVE RESULT IN A QUICK
NORTHWARD TRANSITION OF THE SURFACE LOW PRESSURE CENTER OVER THE
AREA. THIS IS BOTH A WARMER SCENARIO AND WEAKER FOR SOUTHEAST
MICHIGAN IN TERMS OF MESOSCALE FORCING DUE TO LOCAL POSITION WRT THE
SURFACE LOW. THE 00Z ECMWF HAS CHANGED CONSIDERABLY AS IT MODELS
BOTH WAVES WEAKER AND IS CONSIDERABLY STRONGER WITH ITS DEPICTIONS
OF HIGH-LATITUDE ENERGY DIGGING INTO THE GREAT LAKES IMMEDIATELY
BEHIND THE CLIPPER. THIS RESULTS IN A PERIOD OF RATHER BROAD/POORLY
FOCUSED MID-LEVEL FORCING AND A TENDENCY TOWARD A BROAD OPEN SURFACE
WAVE TRANSLATING ACROSS THE AREA ON THURSDAY AFTERNOON. MOVING
FORWARD WITH A GENERAL 1-3" IS STILL PRUDENT AT THIS STAGE AS IT
SEEMS LIKE WE WILL GET THERE ONE WAY OR ANOTHER. ALSO INTRODUCED A
CHANCE OF RAIN FOR THE SOUTHERN TWO TIERS OF COUNTIES ON THURSDAY
AFTN WHERE AMOUNTS ARE MORE LIKELY TO BE AN INCH OR LESS. COLD AIR
WILL FILL IN BEHIND THE CLIPPER DROPPING THURSDAY NIGHT LOWS BACK
INTO THE 10-15F RANGE.

MARINE...

LIGHT TO MODERATE WINDS WILL PERSIST THROUGH THURSDAY AS THE
GRADIENT RELAXES DUE TO RESIDENT HIGH PRESSURE. AN APPROACHING WEAK
LOW PRESSURE WEDNESDAY NIGHT THROUGH THURSDAY WILL CAUSE AN UPTICK
IN SOUTHERLY WINDS, BUT GUSTINESS WILL BE LIMITED TO AROUND 25 KNOTS
DUE TO WARM STABLE FLOW FROM THE SOUTH. COLD AIR MOVING INTO THE
GREAT LAKES IN THE WAKE OF THIS SYSTEM WILL MARK THE BEGINNING OF A
RENEWED STRETCH OF ACTIVE MARINE WEATHER THURSDAY NIGHT INTO NEXT
WEEK AS MULTIPLE BOUTS OF ARCTIC AIR TRAVERSE THE WATERS. THE FIRST
SUCH PERIOD OF ACTIVE WEATHER WILL BE THURSDAY NIGHT WHEN MODERATE
TO STRONG NORTHWEST GALES APPEAR POSSIBLE. THIS PERIOD WILL BE
MONITORED IN THE FOLLOWING FORECAST CYCLES FOR POTENTIAL GALE WATCH
ISSUANCE.

&&

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

$$

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


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


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