Area Forecast Discussion
Issued by NWS Detroit/Pontiac, MI

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958
FXUS63 KDTX 070845
AFDDTX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
345 AM EST SUN FEB 7 2016

.DISCUSSION...

EARLY MORNING OBSERVATIONAL EVIDENCE SUPPORTS THE MORE SUBDUED
PRECIP FORECAST TREND THAT BEGAN IN THE PREVIOUS FORECAST CYCLE FOR
TODAY AND TONIGHT. THE MOISTURE AXIS PRECEDING THE UPPER LOW OVER
THE MIDWEST IS PRODUCING RADAR RETURNS WHILE SURFACE OBS PROVE THIS
TO BE ONLY VIRGA UNTIL FAR NORTHERN WISCONSIN AND UPPER MICHIGAN.
SURFACE OBSERVATIONS OVER THE SOUTHERN PLAINS INDICATE THE RETURN
FLOW OF GULF MODIFIED AIR HAS YET TO DEVELOP IN THE LOW LEVELS WHICH
THE LAST COUPLE OF MODEL RUNS HAVE CAPTURED AND ARE NOW FACTORING
INTO PRECIP POTENTIAL OF THE LOW AS IT MOVES INTO THE GREAT LAKES.
IT DOES LOOK LIKE A MODEST MOISTURE RECOVERY WILL OCCUR BUT IT WILL
BE LATER TONIGHT AND MOSTLY EAST OF OUR AREA AFTER PASSAGE OF THE
COLD FRONT. CHANCE POPS THEN HAVE THE POSSIBILITY WELL COVERED FOR
THE INCOMING MID LEVEL MOISTURE TO PRODUCE A FEW POCKETS OF
SATURATION IN THE DRY LOW LEVEL AIR MASS ALREADY IN RESIDENCE...
MAINLY IN THE TRI CITIES AND NORTHERN THUMB REGION.

THE LACK OF PRECIPITATION TODAY WILL OPEN THE DOOR FOR A RUN OF
TEMPERATURES FARTHER INTO THE MID 40S IN MODERATE SOUTHWEST LOW
LEVEL FLOW DURING THE AFTERNOON. MODEL SOUNDINGS INDICATE THE
BOUNDARY LAYER MIXING INTO THE 950-925 MB RANGE...GOOD ENOUGH FOR
GUSTS NEAR 20 KNOTS TO SUPPORT THE SURGE OF WARMER AIR. MILD
CONDITIONS WILL ALSO LINGER THROUGH TONIGHT EVEN BEHIND THE MODEST
COLD FRONT/OCCLUSION WITH TEMPERATURES PROJECTED TO TAKE MOST OF THE
NIGHT TO DROP BELOW FREEZING. THIS WILL MITIGATE THE IMPACT OF RAIN
SHOWERS CHANGING TO SNOW SHOWERS AS THE PROFILE COOLS ALOFT SUBJECT
TO THE MOISTURE LIMITATIONS MENTIONED ABOVE. THE SURFACE LOW IS ALSO
SHOWN IN THE MODELS TO BE FILLING AND BROADENING AS IT MOVES FROM
CENTRAL CANADA TODAY TO ABOUT THE STRAITS AREA MONDAY MORNING. THE
RESULTING WEAK LOW LEVEL FLOW WILL NOT BE FAVORABLE FOR DRIZZLE
PRODUCTION EVEN IF AN ORGANIZED MID LEVEL DRY SLOT CAN MATERIALIZE.

THE LOW PRESSURE SYSTEM WILL REMAIN ALMOST DIRECTLY OVER SE MICHIGAN
MONDAY AND TUESDAY. THE SURFACE REFLECTION WILL REMAIN BROAD WITH
THE BULK OF LOW LEVEL CONVERGENCE TO OUR EAST IN LOOSE MODEL
AGREEMENT THAT WILL BE SUBJECT TO ADJUSTMENT IN LATER FORECAST
CYCLES. THE GENERAL ENVIRONMENT IN THE LATEST MODEL DEPICTIONS
FAVORS SCATTERED COVERAGE OF SNOW SHOWERS MONDAY INTO MONDAY NIGHT
IN STEEPENING LAPSE RATES UNDER THE COLD POOL ALOFT AND WITH LITTLE
TO NO LOW LEVEL FOCUSING MECHANISM. THE LACK OF LOW LEVEL SUPPORT
WILL BE PARTIALLY COMPENSATED FOR BY IMPROVING NW FLOW AND LAKE
EFFECT CONTRIBUTIONS THAT WILL BECOME BETTER ORGANIZED FOR MORE
NUMEROUS SNOW SHOWER COVERAGE TUESDAY...AND EVEN INTO WEDNESDAY AS
THE SYSTEM BEGINS MOVING AWAY. THE LATEST GLOBAL MODELS CONTINUE TO
INDICATE THE LOW EXITING THE GREAT LAKES THURSDAY WHICH WILL ALLOW
ARCTIC AIR TO FLOOD OVER LOWER MICHIGAN AND CAUSE MAX TEMPS TO
STRUGGLE INCREASINGLY TO HOLD THE 20S WEDNESDAY THROUGH FRIDAY. THE
ECMWF THEN OFFERS A DIRECT HIT BY A REINFORCING 1045 MB ARCTIC HIGH
BY NEXT WEEKEND WHILE THE GFS SUGGESTS A SHOT GLANCING THROUGH THE
NORTHERN GREAT LAKES INTO THE NEW ENGLAND STATES. EITHER WAY...A
ROUND OF WELL BELOW NORMAL TEMPERATURES IS A GOOD BET WITH THE
DIFFERENCES BEING BETWEEN SINGLE DIGIT HIGHS OR HIGHS IN THE TEENS
NEXT WEEKEND.

&&

.MARINE...

MODERATE SSW WINDS WILL CONTINUE THROUGH THIS EVENING BEFORE
DIMINISHING CONSIDERABLY TONIGHT INTO TUESDAY AS EXPANSIVE LOW
PRESSURE SETTLES ACROSS THE GREAT LAKES. WINDS WILL BACK TO
NORTHWESTERLY BY LATE TUESDAY INTO WEDNESDAY AND INCREASE AS LOW
PRESSURE DEPARTS DURING THE MIDWEEK PERIOD. NO HEADLINES ARE
ANTICIPATED AT THIS TIME.

&&

.AVIATION...ISSUED 1151 PM EST SAT FEB 6 2016

VFR CONDITIONS WILL GENERALLY PREVAIL INTO MUCH OF SUNDAY AS MID
LEVEL CLOUDS LOWER FROM 10-12KFT TO 6-8KFT TONIGHT INTO SUNDAY. SW
WINDS WILL PERSIST AND INCREASE INTO MIDDAY SUNDAY AS THE PRESSURE
GRADIENT TIGHTENS IN ADVANCE OF NEXT APPROACHING TROUGH. LOWER VFR
TO MVFR CIGS WILL THEN BEGIN TO FILTER BACK INTO TERMINALS...MAINLY
MBS...BY SUNDAY EVENING AS THIS TROUGH PROGRESSES INTO LOWER MI.

AT DTW...CIGS SHOULD REMAIN 10KFT OR MORE OVERNIGHT AND 6-8KFT ON
SUNDAY WITH SSW FLOW. AS THE FLOW VEERS SLIGHT TO SW LATE IN THE
FORECAST...CIGS MAY APPROACH MVFR ONCE AGAIN. WINDS WILL PEAK MIDDAY
SUNDAY WITH GUSTS TO 20-22 KNOTS FROM 180-200 DEGREES.

//DTW THRESHOLD PROBABILITIES...

* LOW FOR CIGS AOB 5KFT AFTER 04Z SUNDAY EVENING.

&&

.DTX WATCHES/WARNINGS/ADVISORIES...

MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MICHIGAN WATERS OF LAKE ERIE...NONE.

&&

$$

DISCUSSION...BT
MARINE.......JVC
AVIATION.....DG


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



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