000
FXUS63 KGRR 032350
AFDGRR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
650 PM EST TUE DEC 3 2013

LATEST UPDATE...
AVIATION

.SYNOPSIS...
ISSUED AT 340 PM EST TUE DEC 3 2013

A STORM SYSTEM DEVELOPING OVER THE SOUTHERN PLAINS WILL HEAD
TOWARD THE NORTHERN GREAT LAKES BY WEDNESDAY EVENING. THAT WILL
BRING A WARM FRONT ACROSS THE AREA BY MID MORNING WEDNESDAY.
OCCASIONAL RAIN AND AREAS OF FOG ARE EXPECTED AHEAD OF THE WARM
FRONT TONIGHT. AREAS OF LIGHT FREEZING RAIN...MIXED WITH SNOW NEAR
AND NORTH OF ROUTE 10 SHOULD END BY MID EVENING.

THE COLD FRONT FROM THAT DEVELOPING STORM WILL CROSS THE AREA
AROUND MIDNIGHT WEDNESDAY NIGHT. SHOWERS AND TEMPERATURES IN THE
50S WILL PRECEDE THE COLD FRONT. GUSTY WINDS WITH SCATTERED LIGHT
SNOW SHOWERS ARE EXPECTED THURSDAY INTO THURSDAY NIGHT. A MORE
SIGNIFICANT STORM MAY BRING WIDESPREAD SNOW TO THE AREA LATE IN THE
WEEKEND. THAT WILL BE FOLLOWED BY THE COLDEST AIR SINCE LATE
JANUARY OF LAST YEAR.

&&

.SHORT TERM...(THIS EVENING THROUGH THURSDAY NIGHT)
ISSUED AT 340 PM EST TUE DEC 3 2013

THE MAIN ISSUES FOR THIS PART OF THE FORECAST ARE THE ENDING OF
THE FREEZING PRECIPITATION EVENT (NOT MUCH REALLY HAPPENING WITH
THAT)... THE FOG POTENTIAL FOR TONIGHT... THEN THE POTENTIAL FOR
LAKE EFFECT SNOW SHOWERS (NO BIG DEAL EITHER) THURSDAY AFTERNOON
INTO THURSDAY NIGHT.

THE MODELS HAVE COME INTO MUCH BETTER AGREEMENT THIS TODAY SO THE
FORECAST CONFIDENCE IS MUCH HIGHER TODAY THEN YESTERDAY.
BASICALLY A 160 KNOT JET STREAK MOVING THROUGH UPSTREAM PART OF
THE LONGWAVE TROUGH OVER WESTERN CONS AND CANADA HELPS QUICKLY
DEEPEN A STORM SYSTEM THAT IS CURRENTLY DEVELOPING OVER EASTERN
COLORADO. THAT SYSTEM HEADS FOR LAKE SUPERIOR WEDNESDAY EVENING
PUSHING THE WARM FRONT THROUGH THE AREA MID MORNING WEDNESDAY. THE
COLD FRONT FOLLOWS AROUND MIDNIGHT OR SO WEDNESDAY NIGHT.

THE WARM FRONT AHEAD OF THE SYSTEM HAS AREAS OF RAIN SHOWERS AHEAD
OF IT ACROSS IN/IL/WI/LK MI AND LOWER MICHIGAN. THERE IS DECENT
ISENTROPIC LIFT AND LOW TO MID LEVEL FRONTOGENESIS (AS ONE WOULD
EXPECT WITH A 160 KNOT 300 MB JET HEADING THIS WAY). THE ROAD TEMP
SENSORS SHOW THE ROUTE 10 ROAD TEMPS RISING TOWARD FREEZING NOW
AND SURFACE TEMPS ARE AT FREEZING. I EXPECT THE WARM ADVECTION TO
BRING TEMPS ABOVE FREEZING BY EARLY EVENING SO THAT SHOULD NO
LONGER BE MUCH OF AN ISSUE TONIGHT. OTHERWISE THE AREA OF SHOWERS
WILL GRADUALLY LIFT NORTH WITH THE WARM FRONT TO BY MIDNIGHT THE
SHOWERS SHOULD MOSTLY BE NEAR ROUTE 20 OR SO. WIDESPREAD FOG IS
EXPECTED BUT IT IS A QUESTION OF JUST HOW DENSE IT WILL GET GIVEN
THE EXTENSIVE CLOUD COVER ALREADY IN PLACE.

WEDNESDAY SHOULD MOSTLY BE QUIET IN THE MID TO LATE MORNING BUT
THEN SHOWERS ASSOCIATED WITH THE ACCELERATING COLD FRONT SHOULD
CROSS THE AREA DURING THE AFTERNOON INTO MID EVENING. I DO NOT
EXPECT RAINFALL TO BE HEAVY AT THIS POINT.

BEHIND THE FRONT WE GET THE DRY SLOT THURSDAY MORNING BUT THEN AS
THE COLD AIR COMES IN THE GFS DOES SHOW NEAR SATURATION IS THE DGZ
THURSDAY EVENING INTO THURSDAY NIGHT AND THE AIR IS COLD ENOUGH
FOR LAKE EFFECT SNOW SHOWERS. HOWEVER WE ARE NOT ON THE CYCLONIC
SIDE OF THE POLAR JET SO I DO NOT EXPECT THIS TO BE MUCH OF A SNOW
PRODUCER. JUST BREEZY WITH FALLING TEMPERATURES DURING THE DAY
TIME HOURS OF THURSDAY AS THE ASPECT MOST PEOPLE ARE LIKELY TO
NOTICE.

.LONG TERM...(FRIDAY THROUGH TUESDAY)
ISSUED AT 340 PM EST TUE DEC 3 2013

HE MAIN CHALLENGE IN THE LONG TERM DEALS WITH THE POTENTIAL FOR
SNOW FRIDAY.

MODELS ARE TRENDING NORTH WITH THE TRAC OF THE WAVE OF LOW PRESSURE
THAT  RIDES UP THE OHIO VALLEY.  THE NAM IS CLIPPING MY SOUTHERN
FORECAST AREA WITH A PERIOD OF SNOW...AND IS IN LINE WITH THE 00Z
FIM.  DECENT FGEN NOTED WITH THIS SYSTEM.  THE GFS AND HIGH RES EURO
ARE STILL WELL SOUTH OF THE MI/IN BORDER WITH THE SNOW.  THIS SYSTEM
IS STILL LOCATED FAR AWAY FROM MI AT THIS TIME...WEST OF THE BAJA CA
SO CONFIDENCE IS NOT HIGH.    BASED ON THE TRENDS...WILL INCREASE
POPS FOR FRIDAY...ESPECIALLY FROM AZO TO JXN.  WILL NEED TO CONTINUE
TO  MONITOR TRENDS.  THE MID LEVEL FLOW HAS BEEN BACKING WITH TIME.
IF THAT CONTINUES...MORE SNOW WILL BE NEEDED IN THE FORECAST.

INCREASING CONFIDENCE ON A PERIOD OF SNOW SUN NIGHT.  WAVE OF LOW
PRESSURE IS TO RIDE UP THE OH VALLEY SPREADING SNOW INTO MI.  WE
COULD END UP WITH SOME IMPACT FROM THE THIS SYSTEM.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING)
ISSUED AT 641 PM EST TUE DEC 3 2013

IFR AND LIFR WILL BE WIDESPREAD OVERNIGHT AS LOW CLOUDS AND FOG
WILL BLANKET SOUTHERN LOWER MICHIGAN. ONLY DRIZZLE AND SCATTERED
SHOWERS ARE EXPECTED AND ICING SHOULD NOT BE A PROBLEM AS
TEMPERATURES AND DEW POINTS REMAIN ABOVE FREEZING. CONDITIONS
SHOULD SLOWLY IMPROVE ON WEDNESDAY...BUT IFR MAY PREVAIL MUCH OF
THE DAY. WINDS WILL BE EAST TO SOUTHEAST AOB 10 KNOTS.

&&

.MARINE...
ISSUED AT 340 PM EST TUE DEC 3 2013

WE WILL LIKELY NEED A SMALL CRAFT ADVISORY WEDNESDAY NIGHT AS THE
COLD AIR COMES IN BUT TIME SECTIONS ARE ONLY SHOWING 25 TO 35 KNOT
WINDS IN THE BOUNDARY LAYER BEHIND THE FRONT SO THIS DOES NOT LOOK
LIKE A GALE WIND SORT OF EVENT TO ME AT THIS POINT.


&&

.HYDROLOGY...
ISSUED AT 340 PM EST TUE DEC 3 2013

NO BIG ISSUES UNTIL THE COLD AIR MOVES BACK IN AND RIVERS START TO
FREEZE AGAIN. ICE JAMS MAY BE A PROBLEM NEXT WEEK.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&

$$

SYNOPSIS...WDM
SHORT TERM...WDM
LONG TERM...MJS
AVIATION...OSTUNO
HYDROLOGY...WDM
MARINE...WDM