Area Forecast Discussion
Issued by NWS Detroit/Pontiac, MI

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FXUS63 KDTX 081329
AFDDTX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
829 AM EST MON FEB 8 2016

.UPDATE...

IN LIGHT OF CURRENT OBSERVATION TRENDS...AN UPDATE WILL BE ISSUED
TO DROP AFTERNOON HIGHS A COUPLE DEGREES AND INCREASE PRECIP
CHANCES AROUND PORT HURON. OVERALL THE CURRENT FORECAST REMAINS
VALID AS THE PERSISTENT DEFORMATION BAND SLOWLY PUSHES BACK TOWARD
THE EAST TODAY. ALTHOUGH PRECIP WILL GRADUALLY TRANSITION TO SNOW
THIS AFTERNOON...BOUNDARY LAYER TEMPS WILL REMAIN WARM ENOUGH TO
INHIBIT ACCUMULATIONS THROUGH LATE AFTERNOON.

&&

.AVIATION...ISSUED 648 AM EST MON FEB 8 2016

A GENERAL TREND TOWARD MORE PERSISTENT MVFR CEILING IS EXPECTED TO
PROGRESS DURING THE LATE MORNING AND AFTERNOON. THIS WILL OCCUR AS
COOLER AIR FILTERS IN FROM THE WEST WITH A SECONDARY FRONT AND AS
MOISTURE MOVES UP FROM THE OHIO VALLEY ASSOCIATED WITH A STRONG
CIRCULATION ALOFT. ANY PRECIPITATION WILL BE LIGHT RAIN THROUGH
THE DAY AS BOUNDARY LAYER TEMPERATURE WILL BE COOLER BUT NOT
ENOUGH FOR SNOW UNTIL CLOSER TO SUNSET. THE CIRCULATION MOVING UP
FROM THE OHIO VALLEY TODAY IS THEN EXPECTED TO INTENSIFY NEAR THE
SOUTH END OF LAKE HURON. THIS PROCESS WILL RESULT IN INCREASING
COVERAGE OF IFR SNOW SHOWERS THAT WILL OCCUR MOSTLY OVER THE
THUMB THROUGH TUESDAY MORNING. THIS IS SUBJECT TO ADJUSTMENT AND
IFR VISIBILITY IN HEAVIER SNOW SHOWERS COULD OCCUR IN THE TERMINAL
CORRIDOR OVERNIGHT. THIS WILL BE MONITORED FOR BETTER EVIDENCE
BEFORE ADDING TO THE TAF.

AT DTW... MOISTURE MOVING UP FROM THE OHIO VALLEY WILL ONLY
PRODUCE SPRINKLES OF LIGHT RAIN FROM LATE MORNING THROUGH THE
AFTERNOON...BUT WILL COMBINE WITH COOLER AIR MOVING IN FROM THE
WEST FOR GREATER COVERAGE OF MVFR CEILING. MVFR CEILING AND
VISIBILITY WILL OCCUR WITH GREATER FREQUENCY OF SNOW SHOWERS
TONIGHT. LIGHT ACCUMULATION IS POSSIBLE BY SUNRISE TUESDAY...LESS
THAN 1 INCH.

//DTW THRESHOLD PROBABILITIES...

* HIGH FOR CEILING 5000 FT OR LESS TODAY AND TONIGHT.

* HIGH FOR RAIN AS PRECIPITATION TYPE TODAY...AND SNOW TONIGHT.

&&

.PREV DISCUSSION...ISSUED 337 AM EST MON FEB 8 2016

DISCUSSION...

NWP CONTINUE TO STRUGGLE WITH ENERGETIC FLOW ACROSS NOAM AT PRESS
TIME. VERY DYNAMIC TROUGH IS CLOSING OFF OVER THE WESTERN GREAT
LAKES THIS MORNING. ITS EVOLUTION HAS LARGELY BEEN GUIDED BY A VERY
HIGH AMPLITUDE UPSTREAM RIDGE AND A POWERFUL LOW DEEPENING OFF THE
EASTERN SEABOARD IMMEDIATELY DOWNSTREAM. INTERACTION WITH A 165KT
SUBTROPICAL JET STREAKING ACROSS THE GULF COAST STATES WILL
ADDITIONALLY GUIDE THE DEEPENING LONGWAVE THROUGH TUESDAY.

THE EMBEDDED WAVE OVER SAINT LOUIS AT 06Z THIS MORNING WAS
UNIVERSALLY UNDERSIMULATED BY PRIOR MODEL CYCLES AND BETTER SAMPLING
HAS ALLOWED GUIDANCE TO CONVERGE TOWARD A MORE IMPACTFUL EVOLUTION
LOCALLY. SPECIFICALLY, AS THIS WAVE PIVOTS FROM STL TO LAKE ERIE,
WEAK SURFACE CYCLOGENESIS IS ANTICIPATED INVOF THE LAKE. DEEP MOIST
CYCLONIC UPPER FLOW WILL PROVIDE A FAVORABLE BACKGROUND WITHIN WHICH
DEFORMATION AND STRONG SURFACE CONVERGENCE WILL BECOME INCREASINGLY
ORGANIZED OVER LAKE HURON THROUGH THIS EVENING. CONFIDENCE THEN
DECREASES DRAMATICALLY AS NWP SPREAD FALLS INTO AT LEAST 3 DISTINCT
CAMPS. THE EC/ARW/NMM REPRESENT THE STRONGEST CLUSTERING THROUGH THE
INITIAL CYCLOGENESIS AND THIS PREFERRED CLUSTER IS MOST STRONGLY
REPRESENTED IN THE FORECAST. THE GFS/HRRR REMAIN THE MOST
SIGNIFICANT OUTLIERS AND CONFIDENCE IN THOSE SOLUTIONS IS FURTHER
DIMINISHED BY UNUSUALLY VOLATILE RUN-TO-RUN CONTINUITY BY THE
RAP/HRRR.

THROUGH 06Z TONIGHT, CONFIDENCE IS REASONABLY HIGH THAT THE
ORGANIZING SURFACE TROUGH WILL BEGIN TO PIVOT ONSHORE IN THE THUMB.
HAVING ORGANIZED OVER THE RELATIVELY WARM LAKE WATERS IN A MODESTLY
UNSTABLE ENVIRONMENT , THERE IS POTENTIAL FOR SUBSTANTIAL MOISTURE
POOLING AND THE FORECAST WILL HAVE TO BE MONITORED FOR A POTENTIAL
OVERACHIEVING SCENARIO. THE NMM/ARW THEN ALLOW THE SURFACE
CIRCULATION TO LATCH ON TO LAKE ERIE. ADDITIONAL DEEPENING BY A FEW
ADDITIONAL MILLIBARS OVER THE LAKE -A PERFECTLY REASONABLE SCENARIO-
THE STRENGTHENING CIRCULATION AND CONTINUED ONSHORE MOVEMENT OF THE
SURFACE TROUGH OFFER POTENTIAL FOR SEVERAL ADDITIONAL INCHES OF SNOW
AS WELL AS MORE AGGRESSIVE INLAND PENETRATION. THE MORE COARSE EC
EXPECTEDLY PEELS THE LOW AWAY FASTER, CONFINING ACCUMS TO A SMALLER
RANGE AND TO A SMALLER PORTION OF THE THUMB. CONSENSUS EC/ARW/NMM
QPF YIELDS 12-HOUR ACCUMULATIONS OF 2-4" OVER THE NEXT 24 HOURS AND
24-HOUR TOTALS OF 4-7" IN EASTERN PORTIONS OF THE THUMB. THERE
REMAINS CONSIDERABLE UNCERTAINTY IN THE EVOLUTION OF CRITICAL
SURFACE FEATURES, BUT POTENTIAL FOR A WWA-WORTHY SCENARIO IS HIGH
ENOUGH TO WARRANT TAKING AN INITIAL STAB AT A HEADLINE. WORTH NOTING
THAT 06Z NAM REMAINS A BIT OF AN OUTLIER, BUT HAS SHOWN A STRONG
ADJUSTMENT TOWARD AFOREMENTIONED PREFERRED CONSENSUS.

FOR TODAY, EXPECTING LITTLE MORE THAN OCCASIONAL LIGHT SHOWERS
ACROSS THE EASTERN CWA AS BOUNDARY LAYER TEMPERATURES LIKELY REMAIN
TOO WARM TO SUPPORT SNOW UNTIL NEAR OR SHORTLY AFTER SUNSET.

A LATE WEEK CLIPPER WILL POTENTIALLY BRING LIGHT ACCUMULATIONS ON
FRIDAY IN ADDITION TO MARKING THE LEAD EDGE OF A MUCH COLDER
AIRMASS. HIGHS WILL STRUGGLE TO REACH 20 DEGREES WITH SAT AND/OR
SUNDAY POTENTIALLY STRUGGLING TO REACH 10 DEGREES. CONSECUTIVE
MORNINGS OF SUB-ZERO LOWS WILL ALSO BE POSSIBLE AND WIND CHILL
READINGS MAY APPROACH ADVISORY CRITERIA AT TIMES.

MARINE...

A BROAD AREA OF LOW PRESSURE WILL SETTLE OVER LAKE HURON AND LOWER
MICHIGAN TODAY. THIS WILL LEAD TO LIGHT AND VARIABLE WIND OVER
MARINE AREA TODAY THROUGH TONIGHT BUT WITH AN INCREASINGLY ACTIVE
SNOW SHOWER PATTERN. THE SYSTEM WILL DRIFT TOWARD LAKE ONTARIO
DURING TUESDAY AND LEAVE NORTHERLY WIND INCREASING TO MODERATE
STRENGTH BY TUESDAY NIGHT. WHILE WIND HEADLINES ARE NOT
ANTICIPATED...MARINE CONDITIONS WILL WORSEN AS COLDER AIR MOVES IN
AND COMBINES WITH THE MODERATE WIND FIELD FOR BUILDING WAVES AND
STRONGER SNOW SQUALLS. THIS WILL LAST INTO THURSDAY AND THEN WIND
WILL DIMINISH THROUGH FRIDAY WHILE ARCTIC AIR REMAINS IN PLACE INTO
NEXT WEEKEND.

&&

.DTX WATCHES/WARNINGS/ADVISORIES...
MI...WINTER WEATHER ADVISORY FROM 9 PM THIS EVENING TO 7 PM EST TUESDAY
     FOR MIZ049-054-055-062-063.

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

$$

UPDATE.......SC
AVIATION.....BT
DISCUSSION...JVC
MARINE.......BT


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