Area Forecast Discussion
Issued by NWS Detroit/Pontiac, MI

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FXUS63 KDTX 261041
AFDDTX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
541 AM EST MON JAN 26 2015


.AVIATION...

DRY NORTHEAST FLOW WILL PROVIDE VFR CONDITIONS TODAY AS ONLY MID TO
UPPER LEVEL CLOUDS AOA 15KFT ARE EXPECTED TO INCREASE. THE ONLY LOW
CLOUDS TO SPEAK OF...BKN MVFR CIGS OFF OF LAKE HURON...HAVE SHIFTED
LARGELY NORTH OF MBS EARLY THIS MORNING. DEVELOPING STORM OVER THE
NORTHEAST MAY WRAP SOME LOWER MOISTURE BACK INTO THE FAR SOUTHEAST
CWA TONIGHT...BUT CONFIDENCE IS RATHER LOW AT THIS POINT...SO WILL
PRECLUDE ANY LOWER CIGS ATTM.

//DTW THRESHOLD PROBABILITIES...

* NONE

&&

.PREV DISCUSSION...ISSUED 302 AM EST MON JAN 26 2015

SHORT TERM...TODAY AND TONIGHT

COLD TEMPERATURES WILL PERSIST TODAY AND TONIGHT AS NORTHEAST FLOW
CONTINUES TO FEED INTO AREA FROM LARGE HIGH PRESSURE SYSTEM CENTERED
JUST TO THE NORTH OF THE AREA. HIGHS THIS AFTERNOON WILL CLIMB TO
AROUND 20 DEGREES WITH LOWS TONIGHT FALLING BACK INTO THE SINGLE
DIGITS TO LOWER TEENS.

THIS TEMPERATURE FORECAST...ESPECIALLY FOR TONIGHT...IS COMPLICATED
BY A TRICKY CLOUD FORECAST AS VARIOUS SOURCES OF CLOUDS WILL EXIST
THROUGHOUT THE NEXT 24 HOURS. INITIAL MID LEVEL CLOUDS ASSOCIATED
WITH SHORTWAVE PHASING INTO MAJOR EAST COAST STORM WILL EXIT THE
AREA EARLY THIS MORNING...LEAVE A FAIR AMOUNT OF THE CWA PARTLY TO
MOSTLY SUNNY FOR A TIME. MEANWHILE...LOWER STRATUS ASSOCIATED WITH
COLD EAST TO NORTHEAST FLOW FROM LAKE HURON WILL LINGER OVER THE
NORTHERN THUMB AND SAGINAW VALLEY THIS MORNING BEFORE ERODING AND
SHIFTING NORTH AS THE LOW LEVEL FLOW GRADUALLY VEERS TO A MORE
EASTERLY DIRECTION. DURING THE WHOLE TIME...ADDITIONAL HIGH MID TO
UPPER LEVEL CLOUDS WILL SPILL BACK INTO AREA AS ADDITIONAL JET
ENERGY DIGS SHARPLY INTO DEVELOPING UPPER TROUGH/STORM OVER THE
NORTHEAST CONUS.

BETWEEN THESE UPPER LEVEL CLOUDS...WHICH WILL PERSIST INTO TONIGHT
AND LOWER CLOUDS PIVOTING BACK INTO OR NEAR PARTS OF AREA FROM THIS
EVENING INTO THE OVERNIGHT AS THE EAST COAST SYSTEM BOMBS
OUT...EXPECT MOSTLY CLOUDY SKIES FOR MUCH OF THE AREA. PARTS OF THE
THUMB MAY BE THE EXCEPTION AS DRIER LOW FROM THE AFOREMENTIONED HIGH
WILL WEDGE IN BETWEEN THESE OTHER TWO MOISTURE SOURCES. GIVEN THIS
EXPECT THE LOWEST TEMPERATURES OVER THIS PART OF THE CWA...NOT AN
UNCOMMON OCCURRENCE BY ANY MEANS.

LONG TERM...

WATER VAPOR IMAGERY REVEALS BROAD RIDGING IN PLACE ACROSS THE
WESTERN UNITED STATES AND FAR EAST PACIFIC. TO THE EAST, A CLIPPER
HAS BEGUN THE EARLY STAGES OF A RAPID DEVELOPMENT SEQUENCE INTO A
CLASSIC COASTAL CYCLONE. UPPER-LEVEL FLOW OVER THE GREAT LAKES WILL
REMAIN NORTHWESTERLY AS IT WILL BE POSITIONED BETWEEN THESE TWO
PRIMARY PLAYERS IN THE LONGWAVE CONFIGURATION. THE UPSTREAM RIDGE
WILL, HOWEVER, BEGIN TO FEEL THE PINCH OF EAST PAC TROUGH IN
RELATIVELY SHORT ORDER AS IT ABSORBS THE BAJA LOW AND CAUSES RAPID
LONGWAVE DEAMPLIFICATION ACROSS THE WEST ON TUESDAY AS THE ENERGY
RACES EAST. THIS WILL IN TURN SHUNT A STOUT SHORTWAVE RIDGE ACROSS
THE CWA ON TUES, ENSURING THE OVERALL FLOW REMAINS PROGRESSIVE
DESPITE LARGE CYCLONE TO THE EAST.

TUESDAY THROUGH TUESDAY NIGHT WILL THUS BE DOMINATED BY SURFACE HIGH
PRESSURE BENEATH A STOUT MID-LEVEL DRY LAYER. SOME UNCERTAINTY WITH
REGARD TO DIURNAL CLOUD POTENTIAL, BUT THERE HAS BEEN SOME TENDENCY
IN THE NAM TO OVERESTIMATE BOUNDARY LAYER MOISTURE OVER THE LAST FEW
DAYS. A SLIGHTLY LESS AGGRESSIVE DAYTIME CLOUD FORECAST FAVORS HIGHS
IN THE MID 20S...A FEW DEGREES WARMER THAN TODAY. LOWS TUESDAY NIGHT
WILL BE SENSITIVE TO CLOUD COVER STREAMING ACROSS THE RIDGE AXIS
WITHIN QUICK-MOVING NW FLOW. INHERITED FORECAST IN THE UPPER SINGLE
DIGITS PLAYS A REASONABLE MIDDLE-GROUND.

HIGH PRESSURE WILL TRANSLATE EAST ON WEDNESDAY AND RETURN FLOW WILL
TAKE SHAPE AS AFOREMENTIONED PAC ENERGY SUPPORTS DEVELOPING LOW
PRESSURE OVER THE MIDWEST. WARM ADVECTION WILL PUSH HIGHS CLOSE TO
30 DEGREES WEDNESDAY.

A CLIPPER IS FORECAST BY THE SUITE OF GUIDANCE TO SWEEP ACROSS THE
AREA LATE WEDNESDAY NIGHT INTO THURSDAY. GENERAL CONSENSUS IS AT
LEAST 1-3" WITH RESPECTABLE DYNAMICS AND MOISTURE, BUT HURT BY A
WARM THERMODYNAMIC PROFILE. DIFFERENCES IN THE MODELS AT THIS
JUNCTURE ARISE PRIMARILY WITH RESPECT TO THE STRENGTH OF A LEAD
SHORTWAVE WITH ORIGINS IN TODAY`S BAJA LOW. TOO EARLY TO SLICE AND
DICE DETAILS MUCH, BUT THE ECMWF HAS TRENDED TOWARD A MORE DOMINANT
NORTHERN WAVE WHICH WILL SUPPORT BOTH A DEEPER AND MORE PROGRESSIVE
SOLUTION. GFS/GEM ALLOW THE SURFACE LOW TO REMAIN TIED TO THE LEAD
SHORTWAVE WHICH ALLOWS FOR A WEAKER, BUT MORE MATURE, CIRCULATION
CAPABLE OF PRODUCING A MORE RESPECTABLE LOW/MID-LEVEL FGEN RESPONSE
AND HIGHER SNOW TOTALS. GOT THE BALL ROLLING BY INTRODUCING A
GENERAL 1-2" FOR WED NIGHT/THURS.

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 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.

&&

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

$$

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


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



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