FXUS63 KAPX 112312
AFDAPX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GAYLORD MI
612 PM EST FRI DEC 11 2009
.SYNOPSIS.../ISSUED AT 400 PM/
COLD AIR FUNNELING ACROSS THE GREAT LAKES WILL CONTINUE TO PRODUCE
LAKE EFFECT SNOW SHOWERS THROUGH TONIGHT BEFORE COMING TO AN END
EARLY SATURDAY MORNING. HIGH PRESSURE WILL TEMPORARILY BUILD INTO
THE STATE ON SATURDAY WITH SLIGHTLY MILDER AIR RETURNING TO NORTHERN
MICHIGAN. HOWEVER...THIS PUSH OF WARMER AIR WILL ALSO RESULT IN A
RENEWED CHANCE FOR MORE WIDESPREAD LIGHT SNOW FOR THE LATTER HALF OF
THE WEEKEND...WITH SEVERAL ADDITIONAL CHANCES FOR SNOW THROUGH THE
FIRST HALF OF THE COMING WORK WEEK. THEREAFTER...IT APPEARS
INCREASINGLY LIKELY ANOTHER SURGE OF ARCTIC AIR AND PLENTIFUL LAKE
EFFECT SNOWS WILL MAKE AN APPEARANCE FOR THE MIDDLE OF NEXT WEEK.
&&
.SHORT TERM.../ISSUED AT 400 PM/...TONIGHT
HIGH PRESSURE WAS CENTERED OVER KENTUCKY/TENNESSEE AT MID
AFTERNOON...WITH A RIDGE AXIS EXTENDING NORTHWEST IN THE UPPER
MISSISSIPPI VALLEY. WEAKNESS IN THE PRESSURE PATTERN OVER THE
NORTHERN HIGH PLAINS...ASSOCIATED WARM ADVECTION RESULTING IN AN
AREA OF MID CLOUDS ACROSS NORTH DAKOTA/NORTHWEST MINNESOTA AND
ADJACENT AREAS OF MANITOBA/SASKATCHEWAN. THIS AREA OF WEAK LOW
PRESSURE WILL HEAD TOWARD LAKE SUPERIOR OVERNIGHT...THOUGH
ASSOCIATED MOISTURE/LIFT FORECAST TO REMAIN NORTH OF THE FORECAST
AREA. CLOSER TO HOME SNOW SHOWERS CONTINUE ACROSS MUCH OF NORTHERN
LOWER IN WEST-SOUTHWEST FLOW...WHILE SNOW SHOWERS OVER LAKE SUPERIOR
HAVE PUSHED AWAY FROM WHITEFISH BAY. LAKE MICHIGAN BANDS HAVE SHOWN
A QUICK TURN TOWARD A MORE SOUTHWESTERLY ORIENTATION...THOUGH
SATELLITE TRENDS SUGGEST THIS WILL BE BRIEF WITH WINDS COMING BACK
AROUND MORE WESTERLY OVER THE WESTERN PART OF THE LAKE. UPSTREAM
LOW LEVEL RIDGE AXIS WILL CUT ACROSS NORTHERN MICHIGAN OVERNIGHT...
TURNING OVERALL FLOW ANTICYCLONIC WITH TIME. INVERSION HEIGHTS WILL
BECOMING DOWN AS WELL AS OVERALL INSTABILITY WANES. HOWEVER...THERE
WILL BE A BRIEF PERIOD THIS EVENING ACROSS THE TIP OF THE MITT WHERE
SNOW SHOWERS WILL STILL BE MODERATELY INTENSE (WARMING CLOUD LAYER
TEMPERATURES IMPROVING MICROPHYSICS). WILL KEEP 1-3 INCH AMOUNTS
ACROSS PARTS OF CHARLEVOIX/EMMET/CHEBOYGAN COUNTIES FOR THIS
EVENING...WITH INTENSITY WINDING DOWN AS RIDGE AXIS PASSES AND WINDS
BACK TO THE SOUTHWEST. ACROSS EASTERN UPPER...OTHER THAN A FEW SNOW
SHOWERS BRUSHING AREAS AROUND ST. IGNACE MUCH OF THE NIGHT...AND
WHITEFISH POINT FOR A TIME THIS EVENING...SHOULD BE DRY UNTIL LATE
WHEN BACKING WINDS PUSH REMNANT CONVECTIVE BANDS INTO MACKINAC/FAR
SOUTHEAST CHIPPEWA COUNTY. INLAND AREAS OF NORTHERN LOWER SHOULD
SEE CLOUDS DECREASE WITH LOSS OF HEATING...WITH CLEAR/PARTLY CLOUDY
SKIES OVERNIGHT. LOWS TONIGHT IN THESE CLEARING AREAS WILL BE IN
THE SINGLE DIGITS ABOVE AND BELOW ZERO.
WILL LET ALL HEADLINES EXPIRE AT FORECAST ISSUANCE TIME AND FINALLY
PUT THIS EVENT TO BED.
JPB
&&
.LONG TERM.../ISSUED AT 400 PM/...SATURDAY AND BEYOND
SATURDAY THROUGH NEXT FRIDAY...IT LOOKS LIKE WE WILL FINALLY CATCH A
BREAK FROM THE HEAVY LAKE EFFECT FOR A COUPLE OF DAYS DUE TO A
MILDER SOUTHWEST FLOW OVER THE WEEKEND. STILL SOME LINGERING
SOUTHWEST FLOW LAKE EFFECT ON SATURDAY. THEN THERE WILL BE GOOD
CHANCES FOR WARM ADVECTION LIGHT SNOW SATURDAY NIGHT INTO SUNDAY
MORNING AND ANOTHER GOOD CHANCE FOR LIGHT SNOW MONDAY AS A FAST
MOVING AREA OF LOW PRESSURE MOVES THROUGH. NORTHWEST FLOW LAKE
EFFECT THEN LOOKS LIKE A GOOD BET TUE INTO WED AS ANOTHER SHOT OF
ARCTIC AIR PLUNGES DOWN FROM THE NORTHWEST. WE MAY ROUND OUT NEXT
WEEK ON THE QUIETER SIDE AS RIDGING BUILDS IN FROM THE WEST LEADING
TO MODERATING TEMPERATURES...ALTHOUGH A SHORT WAVE DROPPING DOWN
FROM THE NORTHWEST MAY SPOIL THAT IDEA.
SATURDAY...SOME MINOR LAKE EFFECT MAY LINGER AS THE FLOW BACKS FROM
SOUTHWEST TO SOUTH SOUTHWEST. INCREASINGLY WARMER 850 MB
TEMPERATURES THROUGH THE DAY WILL LEAD TO WANING OVER LAKE
INSTABILITY...LIKELY SHUTTING OFF ACTIVITY ACROSS SOUTHWESTERN ZONES
(PLUS MOISTURE IS RATHER SLIM WITH MEAN 1000-850 MB RH ONLY 30 TO 40
PERCENT). OTHERWISE MILDER TEMPERATURES WITH HIGHS IN THE UPPER 20S
TO LOWER 30S.
SATURDAY NIGHT INTO SUNDAY MORNING...A WEAK SHORT WAVE EVIDENT ON
WATER VAPOR LOOP NEAR THE FOUR CORNER REGION WILL LEAD TO
WAA/ISENTROPIC ASCENT LIKELY BRINGING LIGHT SNOW TO THE AREA (AN
INCH OR TWO?) WITH MAYBE SOME SHALLOW LAKE HELP (CONTINUED MARGINAL
850 MB TEMPERATURES).
SUNDAY AFTERNOON AND NIGHT...NOT A WHOLE LOT LOOKS TO BE GOING ON
WITH SHORT WAVE RIDGING THE THEME SHUTTING OFF ANY LINGERING LIGHT
SNOW. THE POSSIBLE EXCEPTION TO THIS IS THAT IT MAY BE JUST COLD
ENOUGH FOR A BIT OF LIGHT LAKE EFFECT ACROSS NORTHERN CHIPPEWA
COUNTY. HIGHS IN THE MILDER LOWER TO MIDDLE 30S. LOWS RANGING FROM
THE UPPER TEENS TO MIDDLE 20S.
MONDAY...ENERGY CURRENTLY EVIDENT ON WATER VAPOR IMAGERY OFF THE
WEST COAST WILL LIKELY BRING THE AREA A PERIOD OF MAINLY LIGHT SNOW.
MILDER WITH HIGHS RANGING FROM THE UPPER 20S TO MIDDLE 30S.
TUESDAY AND WEDNESDAY...ANOTHER SHOT OF ARCTIC AIR WITH 850 MB
TEMPERATURES SHOWN TO BOTTOM OUT IN THE -20 C RANGE EXPECTED TO LEAD
TO A NORTHWEST FLOW LAKE EFFECT EVENT. WILL ADD THE POSSIBILITY
OF SIGNIFICANT SNOWFALL ACCUMULATIONS ACROSS PORTIONS OF NORTHWEST LOWER
AND EASTERN UPPER INTO THE HAZARDOUS WEATHER OUTLOOK. COLDER WITH
HIGHS ONLY RANGING FROM THE MIDDLE TEENS TO THE MIDDLE 20S AND
LOWS IN THE SINGLE DIGITS.
THURSDAY AND FRIDAY...HEIGHTS GENERALLY SPEAKING ARE SHOWN TO BE ON
THE RISE. HOWEVER...A SHORT WAVE MOVING THROUGH THE FLOW WILL BRING
A CHANCE OF SNOW SHOWERS FOR FRIDAY. NOT QUITE AS COLD WITH HIGHS IN
THE 20S.
SULLIVAN
&&
.MARINE.../ISSUED AT 400 PM/
SMALL CRAFT ADVISORY CRITERIA WINDS/WAVES EXPECTED TONIGHT THROUGH
AT LEAST EARLY SATURDAY NIGHT AS A BRISK SOUTHWEST WIND FLOW
PREVAILS. WINDS ARE THEN EXPECTED TO DIMINISH SOMEWHAT OVERNIGHT
SATURDAY INTO SUNDAY. IT IS TO CLOSE TO CALL WHETHER OR NOT SMALL
CRAFTS WILL NEED TO BE EXTENDED. LAKE EFFECT SNOW SHOWERS WILL
WANE LATER TONIGHT INTO SATURDAY WITH A BIT OF LIGHT SNOW LIKELY
SATURDAY NIGHT INTO SUNDAY MORNING.
AJS
&&
.AVIATION.../ISSUED AT 612 PM/...VALID FOR 00Z TAFS
RESIDUAL LAKE EFFECT SNOW SHOWERS AND ACCOMPANYING MVFR/IFR VSBYS
AND CIGS WILL CONCENTRATE AROUND PLN TONIGHT...BEFORE DIMINISHING
THROUGHOUT THE DAY ON SATURDAY. TVC WILL SEE SOME SCATTERED SNOW
SHOWERS...WITH BRIEF PERIODS OF MVFR/IFR CONDITIONS WITHIN HEAVIER
SNOW SHOWERS. APN SHOULD REMAIN FREE FROM SNOW SHOWERS FOR THE NEXT
24 HRS...WITH VFR CONDITIONS EXPECTED.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 11 PM EST SATURDAY FOR LMZ323-341-342-
344>346.
LH...SMALL CRAFT ADVISORY UNTIL 11 PM EST SATURDAY FOR LHZ345>349.
LS...SMALL CRAFT ADVISORY UNTIL 11 PM EST SATURDAY FOR LSZ321-322.
&&
$$
