Area Forecast Discussion
Issued by NWS Detroit/Pontiac, MI

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50

000
FXUS63 KDTX 252044
AFDDTX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
344 PM EST TUE NOV 25 2014

.SHORT TERM...TONIGHT

SNOW SHOWERS THAT HAVE BEEN PRESENT ACROSS MUCH OF THE NORTHERN CWA
WILL SLOWLY DIMINISH TOWARDS NIGHTFALL. STRONG SOUTHWESTERLY WINDS
HAVE ALLOWED LAKE EFFECT BANDS OFF OF LAKE MICHIGAN TO MAKE THEIR
WAY INTO THE SAGINAW VALLEY AND I-69 CORRIDOR FOR MUCH OF THE
AFTERNOON. CURRENT MODEL TRENDS SHOW WEAK MID LEVEL RIDGING TO TAKE
PLACE AFTER 00Z RESULTING IN SURFACE HIGH PRESSURE TO BUILD ACROSS
THE GREAT LAKES REGION TONIGHT. THIS HIGH WILL ALLOW WINDS TO
DIMINISH AND BECOME LIGHT AND VARIABLE OVERNIGHT CAUSING LAKE EFFECT
SNOW SHOWERS TO COME TO AN END. IN ADDITION...THE SOLID STRATUS DECK
OVER SOUTHEAST MICHIGAN WILL BECOME MORE BROKEN OVERNIGHT AS MID
LEVEL DRY AIR FILTERS IN TO THE REGION. LIGHT WINDS AND SOME
CLEARING WILL ALLOW TEMPERATURES TO DROP INTO THE LOW TO MID 20S
ACROSS SOUTHEAST MICHIGAN.

&&

.LONG TERM...

UPPER TROUGH WILL ROTATE THROUGH THE GREAT LAKES ON WEDNESDAY
THROUGH THURSDAY WITH A FAST-MOVING EDGEWAVE DIGGING INTO THE OHIO
VALLEY EARLY ON WEDNESDAY. WITH THE BULK OF FORCING IN THE REGION
TIED TO THIS WAVE AND THE NORTHERN BRANCH TROUGH AXIS STILL WELL
UPSTREAM, SE MICHIGAN WILL BE LEFT IN A RATHER BENIGN ZONE ON
WEDNESDAY CHARACTERIZED BY A NONDESCRIPT SURFACE PRESSURE PATTERN.
LITTLE AIRMASS MODIFICATION FROM TODAY WILL PRODUCE SIMILAR HIGH
TEMPERATURES UNDER CLOUDY CONDITIONS, THOUGH SURFACE WINDS WILL BE 5
KNOTS OR LESS. 12Z NAM SOUNDINGS SUGGEST A SUFFICIENTLY DEEP LAYER
OF BOUNDARY LAYER MOISTURE TO MOVE FORWARD WITH THE INHERITED MOSTLY
CLOUDY FORECAST. A FEW FLURRIES MAY BE POSSIBLE DURING PEAK HEATING
GIVEN MARGINALLY FAVORABLE THERMODYNAMIC PROFILE.

NORTHERN TROUGH WILL APPROACH WED NIGHT INTO THURSDAY WITH CLOUD
COVER AND DECENTLY MIXED CONDITIONS EXPECTED TO LIMIT THURSDAY
MORNING`S LOWS TO THE MID 20S. CROSS-SECTIONS ON THURSDAY REVEAL
VERY HIGH STATIC STABILITY ABOVE 700MB. THIS WILL SIGNIFICANTLY
DAMPEN OR ALTOGETHER ELIMINATE THE VERTICAL RESPONSE TO THE WAVE IN
THE MID-LEVELS. HOWEVER, CONVERGENCE ALONG THE COLD FRONT DOES LOOK
PRETTY SOLID. COMBINED WITH A QUICK HITTING SHOT OF SR ISENTROPIC
ASCENT ON THE 275K SURFACE AND MODEST AUGMENTATION OF THE MOISTURE
FIELD FROM THE LAKE AGGREGATE, COULD SEE A LINE OF SNOW SHOWERS WORK
THROUGH DURING THE HOLIDAY BRINGING A DUSTING TO PERHAPS A HALF INCH
OF ACCUMS. STRONG DEPENDENCE ON SUB-700MB FORCING/DYNAMICS AND SHORT-
LIVED NATURE OF FORCING REALLY SUGGEST NOTHING MORE THAN A CHANCE
POP. ANTICYCLONIC FLOW WILL BUILD IN FOR THURSDAY NIGHT AS COLD HIGH
PRESSURE WORKS INTO THE AREA BEHIND THE FRONT. H85 TEMPERATURES WILL
FALL TO -13C SUPPORTING CURRENT FORECAST LOWS IN THE UPPER TEENS BY
FRIDAY MORNING.

ON FRIDAY...SPRAWLING LOW PRESSURE OVER THE UPPER MIDWEST WILL
BATTLE RETREATING HIGH PRESSURE OVER THE EASTERN SEABOARD. LOW
PRESSURE WILL WIN-OUT AS IT IS ACCOMPANIED BY A LATITUDINAL FLOW 115
KT JET. WITH THE ZONAL FLOW IN PLACE...A RECOVERY TO NEAR NORMAL
TEMPERATURES WILL ENSUE FOR THE WEEKEND. NEXT SURFACE FEATURE /HIGH
PRESSURE OVER NORTHERN CANADA/ WILL GET LITTLE UPPER AIR
SUPPORT...BUT NONETHELESS LOOKS TO BRING COLD TEMPS BACK TO THE
REGION EARLY NEXT WEEK. HAVE TRENDED THOSE GRIDS COOLER WITH
LITTLE CONFIDENCE IN SNOW CHANCES PAST DAY 4.

&&

.MARINE...

WINDS AND WAVES ARE EASING THIS AFTERNOON ALLOWING ALL GALE WARNINGS
TO EXPIRE. SMALL CRAFT ADVISORIES ALONG THE TIP OF THE THUMB HAVE
BEEN EXTENDED THROUGH EARLY THIS EVENING UNTIL SIGNIFICANT WAVE
HEIGHTS FALL BELOW THE 3 TO 5 FOOT THRESHOLD. A WEAK PRESSURE
GRADIENT WILL RESULT IN LIGHT WINDS TONIGHT THROUGH WEDNESDAY NIGHT.
A FAST MOVING LOW PRESSURE WILL THEN BRING A QUICK SHOT OF
NORTHWESTERLY GALES OR NEAR-GALES ON THURSDAY AFTERNOON WHICH SHOULD
BE NO MORE THAN 6 HOURS IN DURATION.

&&

.AVIATION...ISSUED 1214 PM EST TUE NOV 25 2014

//DISCUSSION...

SNOW SHOWERS WILL CONTINUE ACROSS THE NORTHERN TAF SITES /FNT AND
MBS/ THROUGH THE AFTERNOON HOURS. ISOLATED HEAVY BANDS
WILL RESULT IN VISIBILITIES TO DIMINISH IN ANY SNOW BANDS THAT
IMPACT THE SITES. WINDS WILL ALSO CONTINUE TO GUST UP TO 25 KNOTS
BEFORE WEAK MID LEVEL RIDGING BUILDS INTO THE AREA OVERNIGHT.
SNOW SHOWERS WILL COME TO AN END AFTER SUNSET AS WINDS DIMINISH.
CURRENTLY EXPECTING AT LEAST A FEW CLOUDS TO PERSIST OVERNIGHT WITH
A SCATTERED TO BROKEN CLOUD DECK ACROSS SOUTHEAST MICHIGAN.

FOR DTW...CURRENTLY EXPECTING THE BEST CHANCE FOR SNOW SHOWERS TO
REMAIN NORTH OF DTW. HOWEVER...THERE IS STILL A SMALL CHANCE FOR A
BRIEF SNOW SHOWER TO IMPACT THE TERMINAL OVER THE NEXT FEW HOURS.
TIMING OF ANY SHOWERS WILL BE BETWEEN 18Z AND 21Z. EXPECT REDUCED
VISIBILITIES IN ANY SNOW SHOWER ACTIVITY.

//DTW THRESHOLD THREATS...

* HIGH PROBABILITY THAT CEILINGS WILL REMAIN BELOW 5000 FT THROUGH
  THE TAF PERIOD.

* HIGH CONFIDENCE THAT PRECIPITATION WILL REMAIN ALL SNOW BUT LOW
  CONFIDENCE IN TIMING.

&&

.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...SMALL CRAFT ADVISORY UNTIL 7 PM EST THIS EVENING FOR LHZ421-441.

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

$$

SHORT TERM...RK
LONG TERM....JVC/MM
MARINE.......JVC
AVIATION.....RK


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


USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.