Area Forecast Discussion
Issued by NWS Gaylord, MI

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000
FXUS63 KAPX 230813
AFDAPX

AREA FORECAST DISCUSSION...REISSUED
NATIONAL WEATHER SERVICE GAYLORD MI
313 AM EST TUE DEC 23 2014

.NEAR TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 313 AM EST TUE DEC 23 2014

...RAIN/SNOW TURNING TO DRIZZLE THEN JUST STRATUS...

SYNOPTIC PATTERN AND OBSERVATIONS:

EARLY THIS MORNING...SFC LOW AND UPPER LEVEL CLOSED LOW WERE SEEN IN
IA/MO...WITH AN ASSOCIATED MID LEVEL SHORTWAVE/VORT MAX IN NRN IL
WERE RACING INTO THE WESTERN GREAT LAKES. OVERALL RATHER IMPRESSIVE
FORCING WITH THIS WAVE...COMPRISED OF SWATH OF WARM ADVECTION ON
NOSE OF 35-40KT H8 LLJ AND UPPER DIVERGENCE IN LEFT EXIT REGION OF
110KT UPPER JET LIFTING THROUGH THE LOWER OHIO VALLEY. THIS HAS
RESULTED IN A THE INITIAL/FRONT EDGE PRECIPITATION WORKING NORTHWARD
INTO OUR AREA...BUT ALSO WRAPPING BACK WEST AROUND THE UPPER LOW.
THIS HAS SLOWED THE PROGRESSION INTO NE LOWER AND THE SAULT. RAIN
WAS FALLING ACROSS MOST OF THE GTV BAY AND AREAS SOUTH AND WEST OF
THERE...WITH SNOW FALLING ACROSS FAR NW LOWER...AND A MIX OF
FREEZING RAIN WAS FALLING IN WITH THE SNOW INTO THE HIGHER TERRAIN
SOUTH OF M-72 WHERE WARMER AIR LOFT HAS OVERSPREAD SUB FREEZING SFC
TEMPS. VERY LITTLE IF ANY PRECIPITATION IN EASTERN UPPER/NE LOWER
ATTM.

SYNOPTIC PATTERN EVOLUTION AND ASSOCIATED WEATHER:

UPPER LOW/SHORTWAVE AND OCCLUDING SFC LOW LIFT NE THROUGH LAKE
SUPERIOR TODAY AND EXIT BY TONIGHT. AFOREMENTIONED FORCING MAXIMIZES
THIS MORNING WHILE LIFTING NORTH. THIS WILL DRIVE THE PRECIPITATION
THROUGH NRN MICHIGAN THROUGH THE MORNING. DEEPER MOISTURE STRIPS OUT
THROUGH THE DAY FROM SOUTH TO NORTH...AND A PERIOD OF DRIZZLE IS
EXPECTED TO FOLLOW. AT THE SAME TIME...LIGHT FOG SHOULD BE FAIRLY
COMMON. THERE ARE HINTS OF A POSSIBLE CLEAR SKY FOR A TIME LATER
TONIGHT...BUT BELIEVE THIS TO BE A PIPE DREAM. A LIGHT WIND
SCENARIO..OUT OF THE SOUTH...OVER SNOWPACK...IN DECEMBER. DOUBT IT.
IF IN FACT IT DID CLEAR OUT...FOG WOULD QUICKLY DEVELOP.

HIGHS IN THE MIDDLE TO UPPER 30S TODAY....WITH LOW CLOUDS AND LIGHT
FOG LIKELY KEEPING READINGS IN THE MIDDLE 30S MOST AREAS.

&&

.SHORT TERM...(WEDNESDAY THROUGH THURSDAY NIGHT)
ISSUED AT 313 AM EST TUE DEC 23 2014

HIGH IMPACT WEATHER POTENTIAL: POTENTIAL FOR A NARROW STRIPE OF
HEAVY SNOW SOMEWHERE ACROSS NORTHERN MICHIGAN WEDNESDAY AFTERNOON
AND NIGHT...WITH OF COURSE AN INHERENT THREAT FOR HAZARDOUS TRAVEL
SHOULD IT COME TO FRUITION. CONFIDENCE ON THE EXACT PLACEMENT OF
THAT SNOWFALL REMAINS QUITE LOW.

WELL HERE WE GO FOLKS - SHOW TIME! MUCH ADVERTISED STRONG PACIFIC
JET ENERGY/VORTICITY MAXIMA NOW WORKING THEIR WAY THROUGH THE
WESTERN CONUS...WITH A TREMENDOUS 150+ KNOT JET CORE ANALYZED
WORKING DOWN THE SPINE OF THE WESTERN ROCKIES AS OF 06Z. SAID ENERGY
IS HELPING AMPLIFY ALREADY EXISTENT DEEPER CLOSED MID LEVEL CYCLONE
SPINNING AWAY OVER THE CENTRAL PLAINS AT THIS EARLY HOUR...WITH THAT
OVERALL TREND SET TO CONTINUE THROUGH TONIGHT...AS THE UPPER TROUGH
DIGS ALL THE WAY DOWN TOWARD THE NORTHERN GULF OF MEXICO. THAT WILL
INCITE SURFACE CYCLOGENESIS NEAR THE LOUISIANA GULF COAST...WITH
THAT FEATURE ENCOUNTERING EXCELLENT UPPER JET SUPPORT AS IT WORKS
NORTH ON THE FRONT SIDE OF THE EVER-DEEPENING UPPER TROUGH. AS
SUCH...AND HAS BEEN ADVERTISED FOR MANY DAYS NOW...EXPECT A FAIRLY
RAPID INTENSIFICATION OF THE SURFACE LOW AS IT WORKS INTO THE GREAT
LAKES...THOUGH STILL HAVE SOME QUESTIONS REGARDING ITS EXACT
PLACEMENT BY THE TIME IT WORKS TOWARD NORTHERN MICHIGAN. 00Z
GUIDANCE CAME A LONG WAY TOWARD PROVIDING A CONSENSUS...WITH A TRACK
OF THE SURFACE LOW SOMEWHERE BETWEEN CENTRAL LAKE HURON AND
NORTHEAST LOWER MICHIGAN...THOUGH THERE IS STILL SOME SPREAD AMONG
VARIOUS RGEM/GEFS/EPS ENSEMBLE MEMBERS...AS WELL AS AN OVERALL
SLIGHTLY MORE WEST FLAVOR OF THE GFS/GGEM  UNFORTUNATELY...THIS IS A
CASE WHERE LITERALLY A 20 OR 30 MILE DIFFERENCE IN LOW LEVEL CYCLONE
TRACK WILL MEAN THE DIFFERENCE BETWEEN A COLD RAIN...HEAVY WET
SNOW...OR NOTHING. GOOD LUCK!

A SOLID GUESS BASED ON GUT FEELING (ALWAYS IMPORTANT!) AND CONSENSUS
DEEPENS THE STORM WHILE LIFTING NORTHWARD ALONG THE WESTERN LAKE
HURON COAST OR ACROSS NORTHEAST LOWER WEDNESDAY EVENING...WITH
INCREASING MID LEVEL DEFORMATION FORCING AND ELONGATING STRONG
LOW/MID LEVEL FRONTOGENESIS BRINGING ANOTHER ROUND OF PRECIP TO MUCH
IF NOT ALL OF THE CWA FROM ABOUT MIDDAY WEDNESDAY ONWARD INTO
WEDNESDAY NIGHT. DEEPER NATURE OF THE STORM SHOULD HAVE LITTLE
DIFFICULTY WRAPPING BACK A MODEST WARM NOSE DOWN LOW...AT LEAST
INITIALLY...SUGGESTIVE OF RAIN AS THE DOMINANT PRECIP TYPE INTO
WEDNESDAY AFTERNOON. HOWEVER...WITH THE STORM DEEPENING RAPIDLY...
COLD AIR/THICKNESSES SHOULD RAPIDLY CRASH INTO THE BACKSIDE OF THE
PRECIP AXIS. DESPITE ONLY MARGINAL COLD AIR...STRONG UPWARD MOTION/
DYNAMICS SHOULD HAVE LITTLE DIFFICULTY CHANGING RAIN TO SNOW FROM
WEST TO EAST. THE MILLION DOLLAR QUESTION IS HOW FAST THAT OCCURS...
AND HOW FAR EAST THE RAIN/SNOW LINE WILL MAKE IT...AS AGAIN A FEW
MILE DIFFERENCE WILL MAKE A WORLD OF DIFFERENCE AS FAR AS IMPACTS
GO. AT THIS JUNCTURE...HONESTLY JUST NOT READY TO NAIL DOWN A
SPECIFIC STRIPE OF HEAVIER SNOW POTENTIAL IN THE FORECAST...BUT A
GOOD FIRST GUESS WOULD BE SOMEWHERE ACROSS NORTHWEST LOWER AND
WESTERN CHIPPEWA/MACKINAC COUNTIES...WITH WARMER AIR OFF LAKE HURON
KEEPING MUCH OF NORTHEAST LOWER AND PERHAPS THE I-75 CORRIDOR MOSTLY
RAIN. WITH THAT SAID...A SHIFT OF 50-80 MILES TO THE WEST OR EAST
WILL SIGNIFICANTLY CHANGE THAT...AND DO HAVE SOME AT LEAST A LITTLE
CONCERN A MORE WESTWARD TRACK MAY WELL END UP BEING REALITY...AS THE
PRIMARY LOW WRAPS BACK BENEATH THE RAPIDLY CLOSING MID LEVEL
CIRCULATION. STILL...EURO/RGEM ENSEMBLE CONTINUITY HARD TO IGNORE...
BUT WE DO HAVE A FEW MORE GUIDANCE CYCLES TO PERUSE THE DATA. ALL IN
ALL...A HEADLINE MAY ULTIMATELY BE NEEDED FOR A QUICK DUMP OF SOME
HEAVY/WET SNOW IN A FEW SPOTS...THOUGH THE TOTAL AREA OF OUR CWA
IMPACTED MAY BE RELATIVELY SMALL.

SYNOPTIC PRECIP COMES TO AN END RAPIDLY BY SUNRISE CHRISTMAS MORNING
AS OUR LOW RAPIDLY LIFTS TOWARD HUDSON BAY...LEAVING BUILDING MID
LEVEL HEIGHTS AND SUBSIDENCE/DRYING IN ITS WAKE. AIRMASS JUST ISN`T
VERY COLD AT ALL BEHIND THIS SYSTEM (AS THE PACIFIC-FLAVOR TO THE
FLOW REGIME CONTINUES)...WITH REALLY NO LAKE EFFECT CONCERNS AT ALL.
IN FACT...WOULDN`T BE SHOCKED TO SEE SOME LATER DAY SUNSHINE...WITH
QUIET CONDITIONS INTO THURSDAY NIGHT AS WELL WITH LOW LEVEL RIDGING
BRANCHING NORTH FROM THE MID ATLANTIC STATES.

&&

.LONG TERM...(FRIDAY THROUGH MONDAY)
ISSUED AT 313 AM EST TUE DEC 23 2014

ACTIVE WEATHER PATTERN SET TO CONTINUE THROUGH THE WEEKEND AND
BEYOND AS THE WESTERN TROUGH RELOADS...SENDING ANOTHER UPPER TROUGH
IN THE DIRECTION OF THE GREAT LAKES LATE FRIDAY INTO FRIDAY NIGHT.
TRACK OF SAID SYSTEM STILL IN QUESTION...AS IS ITS OVERALL
STRENGTH...BUT THE GENERAL TREND OVER THE PAST 24 HOURS HAS BEEN A
PRONOUNCED NORTHWARD SHIFT...SUCH THAT PARTS OF THE CWA MAY EVEN SEE
A BRIEF WARMUP. WITH THAT SAID...CONFIDENCE IS VERY LOW IN THIS
REGARD AS THE DRIVING WAVE REMAINS WELL OFFSHORE INTO THE GULF OF
ALASKA CURRENTLY (THOUGH IT IS IMPRESSIVELY STRONG).

THEREAFTER...COLLAPSE OF THE PACIFIC PATTERN AND MUCH MORE
COOPERATION FROM OVERALL PACIFIC FORCING MECHANISMS (SEE MUCH
FLATTER MJO/GWO PROGS) SUGGESTS BUILDING WESTERN NORTH AMERICAN
HEIGHTS. THAT SETUP SHOULD LEAD TO A SHARP RETURN TOWARD MUCH MORE
NORMAL LATE DECEMBER/EARLY JANUARY CONDITIONS AS BROAD TROUGHING
DEVELOPS OVER MUCH OF CANADA DOWN THROUGH THE LOWER 48. THAT ALONE
SHOULD UNLOAD MUCH MORE SEASONABLY COLD AIR IN OUR DIRECTION...WITH
OF COURSE INCREASED POTENTIAL FOR LAKE EFFECT SNOW SHOWERS...LIKELY
ENHANCED BY THE OCCASIONAL CLIPPER SYSTEM WITHIN THE MEAN WEST TO
NORTHWEST FLOW REGIME. A LITTLE FAR OUT TO GET TOO SPECIFIC WITH
VERY HIGH POPS GIVEN THE UNCERTAIN EXACT WIND REGIMES...BUT COULD
SEE SOME MODEST ACCUMULATION AT SOME POINT AS WE ROUND OUT THE MONTH
OF DECEMBER.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1242 AM EST TUE DEC 23 2014

WEAKENING LOW PRESSURE WILL CROSS WEST OF THE AIRPORTS TODAY WITH
A BAND OF RAIN AND SNOW LIFTING THROUGH THE REGION THIS MORNING.
THE LOW LEVELS OF THE ATMOSPHERE WILL REMAIN SATURATED TODAY WITH
WIDESPREAD STRATUS. THE PRECIPITATION WILL MAINLY BE RAIN...BUT
PLN WILL CHANGE FROM SNOW TO RAIN AROUND DAYBREAK. THE RAIN
TAPERS OFF TO A PERIOD OF DRIZZLE WITH FOG DEVELOPMENT THIS
AFTERNOON. STRATUS/FOG ENTER THE EVENING ALL AIRPORTS...BUT THERE
IS A CHANCE THAT THIS STRATUS CAN ERODE OUT THIS EVENING...WHILE
JUST MID AND UPPER LEVEL MOISTURE INCREASES. CONFIDENCE IS LOW TO
AVERAGE ON GOING TO VFR LATER TONIGHT. OVERALL...MFR/IFR THIS TAF
PERIOD.

SE WINDS ARE INCREASING OVERNIGHT...STEADY IN THE 10-15MPH
RANGE...DROPPING OFF INTO THE DAY WHILE BECOMING MORE SOUTH.

&&

.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.

LH...SMALL CRAFT ADVISORY UNTIL 7 PM EST THIS EVENING FOR LHZ345>349.

LM...SMALL CRAFT ADVISORY UNTIL 7 PM EST THIS EVENING FOR LMZ323-341-
     342-344>346.

LS...SMALL CRAFT ADVISORY UNTIL 7 PM EST THIS EVENING FOR LSZ321.

&&

$$

NEAR TERM...SMD
SHORT TERM...LAWRENCE
LONG TERM...LAWRENCE
AVIATION...SMD



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