000
FXUS63 KAPX 081035
AFDAPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GAYLORD MI
535 AM EST SUN DEC 8 2013

.SYNOPSIS...
ISSUED AT 436 AM EST SUN DEC 8 2013

LINGERING LAKE EFFECT SNOW SHOWERS AND FLURRIES WILL DIMINISH THIS
MORNING. MEANWHILE...LIGHT TO MODERATE SNOW WILL MOVE IN LATER TODAY
AND CONTINUE INTO TONIGHT...AS LOW PRESSURE MOVES ACROSS THE REGION.
THAT SYSTEM...ALONG WITH A SERIES OF ALBERTA CLIPPERS...WILL USHER
IN VERY COLD AIR OVER THE NEXT FEW DAYS...ALONG WITH ACCUMULATING
LAKE EFFECT SNOWS.

&&

.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 436 AM EST SUN DEC 8 2013

CURRENTLY...WEST FLOW LIGHT SNOW/FLURRIES CONTINUES ACROSS FAR NW
LOWER...BUT INCOMING SFC HIGH PRESSURE IS ALLOWING WINDS TO WEAKEN
WITH TIME. OVERALL PATTERN SHOWING UPPER TROUGH STILL OVER THE
WESTERN CONUS...WITH BROAD/WEAK/SHALLOW RIDGING ACROSS THE SE
STATES. SHORTWAVE ENERGY SEEN IN THE 4 CORNERS...AT THE BASE OF
THE UPPER TROUGH...AND INDUCING SFC LOW PRESSURE LIFTING INTO THE
TEXAS PANHANDLE. A REAL DEEP GULF OF MEXICO MOISTURE FEED IS NOT
EVIDENT IN OBSERVATION OR SHORT TERM DATA...HOWEVER THERE IS A
POCKET OF UPPER DIVERGENCE AND OVERALL WEAK-MODEST DEEP LAYER
-DIVQ IN THE CENTRAL PLAINS...RESULTING IN A SWATH OF LIGHT SNOWS.

TODAY...WEAK SFC OW PRESSURE AND ASSOCIATED SHORTWAVE WILL LIFT
INTO ILLINOIS THIS AFTERNOON AND THEN INTO THE WESTERN GREAT LAKES
BY LATE TONIGHT. WITH LIGHT WINDS OVER THE REGION THIS
MORNING...ANY REMNANT CONVECTION WILL HAVE GRADUALLY KEPT CLOSE TO
THE SHORELINE OF LAKE MICHIGAN OR ACTUALLY OUT OVER THE LAKES.
THIS CONVECTION WILL BE WEAK...BUT IT WILL STILL BE THERE WITH
SUFFICIENT OVERLAKE INSTABILITY. AS HIGH PRESSURE DEPARTS THIS
AFTERNOON...AND WINDS WILL SWITCH OUT OF THE SOUTH AND INCREASE A
BIT AHEAD OF THE APPROACHING LOW PRESSURE. MOISTEN WILL DEEPEN
FROM THE TOP DOWN THROUGH THE DAY...AND WILL EVENTUALLY ACTIVATE
WHATEVER SHALLOW LOW LEVEL CONVECTION IS AROUND. FEEL THAT SOUTH
WINDS WILL BLOW SOME SOMEWHAT ENERGIZED LIGHT SNOW SHOWERS INTO
THE STRAITS AND EASTERN UPPER MICHIGAN IN THE AFTERNOON...BUT
LIKELY WITH LITTLE FANFARE. AMOUNTS BELOW AN INCH SEEMS MORE THAN
LIKELY.

TONIGHT...WARM ADVECTION...UPPER DIVERGENCE AND LIGHT TO MODERATE
DEEP LAYER FORCING ARRIVE...ALTHOUGH NOT TOO IMPRESSIVE. WARM
ADVECTION IS NOT ENOUGH TO END OVERLAKE INSTABILITY EITHER...SO A
GENERAL LIGHT SNOW WILL DEVELOP ACROSS ALL OF NRN MICHIGAN WITH
S/SE WINDS SUPPORTING LAKE ENHANCEMENT OF THE SNOW OVER PRIMARILY
EASTERN CHIP/MACK WHERE FETCH IS LONGEST. STILL RATHER HIGH LIQUID
TO SNOW RATIOS...AND PER PREVIOUS DISCUSSION...A FAIRLY DEEP DGZ
WITH THE BEST OF THE WEAK TO MODERATE LIFT OCCURRING WITHIN THIS
REGION...TO HELP SUPPORT A RATHER MEAGER SNOW PRODUCING SYSTEM.
HAVE SOME QUESTIONS REGARDING TOTAL MOISTURE WITH THIS EVENT...PER
THE AFOREMENTIONED MINIMAL LOW LEVEL GULF MOISTURE SUPPORT. DID
END UP LOWERING SNOWFALL EXPECTATIONS FOR TONIGHT...BUT JUST FOR A
GENERAL 2-3 INCHES...WITH EASTERN SECTIONS OF CHIP/MACK SEEING 5-6
INCHES WITH BEST LAKE SUPPORT. WILL NOT HOIST ANY ADVISORIES
YET...AS WE WOULD ONLY BE LOOKING AT THOSE EASTERN SECTIONS FOR
THOSE...AND THAT IS BETTER LEFT TO FURTHER DISCERN WITH NEWER DATA
LATER TODAY.

&&

.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 436 AM EST SUN DEC 8 2013

REINFORCING SHOTS OF ARCTIC AIR WILL CONTINUE TO FLOW INTO THE
REGION FOR MUCH OF THE WORK WEEK LEADING TO ADDITIONAL BOUTS OF LAKE
EFFECT SNOW SHOWERS. SHIFTING WINDS AND VARYING AMOUNTS OF AVAILABLE
MOISTURE DUE TO WEAK ALBERTA CLIPPER SYSTEMS MOVING THROUGH THE
FLOW...WILL LEAD TO DAILY FORECAST CHALLENGES OVER THE LOCATION AND
INTENSITY OF THE LAKE EFFECT SNOW SHOWERS AND THE RESULTANT
ACCUMULATIONS. HIGHER PRESSURE WILL THEN LIKELY BUILD INTO THE
REGION FRIDAY INTO THE START OF NEXT WEEKEND WHICH SHOULD LEAD TO A
DOWNWARD TREND IN LAKE EFFECT ACTIVITY.

MONDAY MORNING...MOISTURE FROM THE DEPARTING AREA OF LOW PRESSURE
WILL BRING LINGERING LIGHT SNOW TO THE REGION WITH PERHAPS ANOTHER
INCH OR TWO OF ACCUMULATION.

MONDAY AFTERNOON INTO MONDAY NIGHT...ANOTHER SHOT OF ARCTIC AIR WILL
THEN FOLLOW (850 MB TEMPERATURES FALLING TO -19 TO -21 C) AND RESULT
IN MORE LAKE EFFECT SNOW SHOWERS. THE STRONG COLD AIR ADVECTION WILL
LEAD TO GUSTY WINDS AND SOME BLOWING AND DRIFTING SNOW. THE
PREVAILING FLOW WILL BE OUT OF THE WEST WITH DECENT MOISTURE (MEAN
850-700 MB IN THE 60 TO 70 PERCENT RANGE). EXPECT ACCUMULATIONS OF 3
TO 5 INCHES...WITH LOCALLY HIGHER AMOUNTS POSSIBLE. HIGHS IN THE
MIDDLE 20S TO NEAR 30...BUT LIKELY FALLING OFF IN THE AFTERNOON.
LOWS IN THE SINGLE DIGITS ABOVE ZERO.

TUESDAY...AN ALBERTA CLIPPER WILL MOVE BY TO THE NORTH LEADING TO A
PERIOD OF MAINLY LIGHT SNOW (ESPECIALLY ACROSS NORTHERN
COUNTIES)...WITH SOUTHWEST FLOW LAKE ENHANCEMENT. ACCUMULATIONS
RANGING FROM LESS THAN AN INCH SOUTHEAST TO UPWARDS OF A FEW INCHES
IN SOUTHWEST FLOW FAVORED AREAS ALONG THE LAKE MICHIGAN
SHORELINE...THE STRAITS AND EASTERN MACKINAC COUNTY. HIGHS IN THE
MIDDLE TEENS TO AROUND 20.

TUESDAY NIGHT INTO WEDNESDAY NIGHT...A DECENT SLUG OF MOISTURE IS
SHOWN TO DROP DOWN FROM THE NORTHWEST AS WELL AS THE COLDEST AIR OF
THE WEEK (AS 850 MB TEMPS FALL INTO THE -20 TO -22 C). THIS MAY SET
THE STAGE FOR A MORE SIGNIFICANT AND MORE WIDESPREAD LAKE EFFECT
EVENT FOR WEST NORTHWEST FLOW FAVORED AREAS. LOWS IN THE SINGLE
DIGITS TO AROUND 10 ABOVE WITH HIGHS IN THE MIDDLE TO UPPER TEENS AT
BEST.

THURSDAY...LAKE EFFECT SNOW SHOULD CONTINUE...AT LEAST IN A LIGHTER
CAPACITY...AS COLDER AIR CONTINUES TO FLOW ACROSS THE AREA BUT
MOISTURE BEGINS TO WANE. HIGHS IN THE UPPER TEENS TO MIDDLE 20S.

FRIDAY INTO SATURDAY...EXTENDED MODELS BEGIN TO DIVERGE TO A CERTAIN
EXTENT BUT THE GENERAL TREND IS FOR SURFACE HIGH PRESSURE AND
ASSOCIATED DRIER AIR TO DIMINISH LAKE EFFECT ACTIVITY.
HOWEVER...PAST HISTORY HAS TAUGHT US THAT WITH CONTINUED EXCELLENT
OVER LAKE INSTABILITY AND TROUGHING ALOFT...ACTIVITY WILL LIKELY
HOLD ON LONGER THAN ANTICIPATED. HIGHS GENERALLY RANGING FROM THE
UPPER TEENS TO MIDDLE 20S AND LOWS IN THE SINGLE DIGITS AND TEENS
ABOVE ZERO.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 148 AM EST SUN DEC 8 2013

LAST VESTIGES OF LAKE EFFECT LIGHT SNOW AND FLURRIES WITH MVFR
CIGS/VSBYS WILL WIND DOWN THROUGH DAYBREAK OVER PLN IN WEAKENING
WESTERLY FLOW. MID AND HIGHER LEVEL CLOUDS STREAM IN TODAY AND
HELP TO RE-ENERGIZE LAKE CLOUDS WHICH WILL COME INTO APN AS WINDS
TURN SE BEHIND DEPARTING HIGH PRESSURE. SYNOPTIC FORCING AND
MOISTURE INCREASE TO WHERE SYSTEM SNOWS DEVELOP LATE THIS
AFTERNOON...BUT MORE SO TONIGHT WITH IFR CONDITIONS BECOMING
COMMON. THESE SNOWS WILL POTENTIALLY BE ENHANCED BY LAKE HURON AT
APN. BEST SNOWS OVERNIGHT TONIGHT...WITH MAYBE A BRIEF PERIOD OF
TIME WHERE RATES REACH 1"/HR.


&&

.MARINE...
ISSUED AT 436 AM EST SUN DEC 8 2013

SMALL CRAFT ADVISORIES HAVE BEEN CANCELLED...AS INCOMING LOOSER
PRESSURE GRADIENT/SFC HIGH PRESSURE...IS ALLOWING WINDS TO
SUBSIDE. THIS WILL CONTINUE THROUGH THE MORNING AS THE HIGH MOVES
OVERHEAD. WINDS SWING AROUND TO SOUTHEAST BY TONIGHT AS THE HIGH
SHIFTS EAST. WEAK LOW PRESSURE LIFTS THROUGH MONDAY MORNING...WITH
WINDS ABRUPTLY SWITCHING MORE WESTERLY AND INCREASING AGAIN WITH
THE PASSAGE OF A COLD FRONT. ADVISORY LEVEL WINDS A GOD
BET...WITH GALES ALSO POSSIBLE MONDAY AFTERNOON AND NIGHT FOR
MAINLY THE LAKE MICHIGAN NEARSHORES.

&&

.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...NONE.
LM...NONE.
LS...NONE.

&&

$$

SYNOPSIS...AS
SHORT TERM...SD
LONG TERM...AS
AVIATION...SD
MARINE...SD