High Wind in Michigan, October 25 to 26, 2001

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GAYLORD MI
450 PM EDT THU OCT 25 2001

19Z SURFACE MAP SHOWS 978MB OCCLUDED SURFACE LOW OVER CENTRAL LAKE
SUPERIOR...WITH A WEAK AREA OF PRESSURE FALLS OVER EASTERN UPPER. KAPX
88D SHOWS A LARGE AREA OF PRECIPITATION ACROSS EASTERN UPPER AND MUCH
OF NORTHERN LOWER...MAINLY SNOW ACROSS INTERIOR NORTHERN LOWER WITH
RAIN ALONG THE LAKESHORE AND ACROSS MOST OF EASTERN UPPER WHERE IT HAS
BEEN PRETTY MUCH RAINING ALL DAY.  SURFACE WIND GUSTS OUT OF THE
SOUTHWEST HAVE APPROACHED 40KT WITH ONE REPORT OF 51KT NEAR MIO...BUT
OVERALL WINDS HAVE BEEN MORE ADVISORY CRITERIA.  WINDS AND PRECIP
TYPE/AMOUNTS WILL BE THE MAIN FOCUS TONIGHT...WITH WINDS AND SNOW
AMOUNTS FOR FRIDAY.  LOOKS LIKE THINGS SHOULD TAPER OFF FOR THE WEEKEND.

TONIGHT/FRIDAY...SURFACE LOW FORECAST TO PASS JUST NORTH OF THE NORTH
CHANNEL TONIGHT.  SURFACE TROUGH COMBINED WITH A SERIES OF VORTICITY
CENTERS ROTATING AROUND THE LOW SHOULD KEEP LAKE ENHANCED PRECIPITATION
GOING TONIGHT.  WINDS SHOULD BECOME MORE NORTHWEST OVERNIGHT BEHIND THE
TROUGH...WHICH WILL ALLOW FOR A BETTER LAKE EFFECT TYPE SET UP ON
THURSDAY.  PRECIPITATION TYPE WILL BE A PROBLEM INITIALLY AS WARMER LOW
LEVEL AIR BENEATH THE OCCLUSION WRAPS ACROSS EASTERN UPPER AND FAR
NORTHERN LOWER THIS EVENING.  WITH RAIN ALREADY OCCURRING ACROSS
EASTERN UPPER AND THE STRAITS...THIS SHOULD KEEP PRECIPITATION MOSTLY
LIQUID OR A MIX THROUGH MIDNIGHT.  SOME MIXED RAIN AND SNOW ALSO
EXPECTED ALONG THE LAKE MICHIGAN SHORELINE...WITH MAINLY RAIN OR A MIX
ALONG THE LAKE HURON SHORE WHERE TEMPERATURES ARE IN THE LOWER 40S TO
START.  AS LOW PASSES TO THE EAST COLDER AIR FILTERING IN EXPECTED TO
CHANGE PRECIPITATION OVER TO PRETTY MUCH ALL SNOW.  ACROSS EASTERN
UPPER...NORTHWEST LAKE EFFECT PATTERN EXPECTED TO SET UP DURING THE
EARLY MORNING HOURS...INVERSION HEIGHTS UP AROUND 10K FEET ALONG WITH
DEEP MOISTURE...THOUGH 850MB TEMPERATURES ARE MARGINAL AROUND -5C...SO
WILL KEEP ACCUMULATIONS LIGHT TONIGHT (1-2/1-3 INCHES).  ACROSS
NORTHWEST LOWER...WILL ALSO MENTION SOME LIGHT ACCUMULATIONS (1-2
INCHES) ACROSS HIGHER TERRAIN AREAS.  FRIDAY SETTING UP FOR MORE LAKE
EFFECT SNOW SHOWERS...ACROSS EASTERN UPPER INVERSIONS REMAIN AROUND 10K
FEET THROUGH MUCH OF THE DAY...WITH WINDS TURNING MORE TOWARD 340-350
DURING THE AFTERNOON.  MAIN LIMITING FACTOR LIKELY TO BE SOMEWHAT
LIMITED INSTABILITY...AGAIN 850MB TEMPERATURES STILL AROUND -6C WITH
WATER TEMPERATURES AROUND 9C.  WILL MENTION ACCUMULATIONS OF 2-3 INCHES
WITH LOCALLY HIGHER AMOUNTS AT THIS POINT...AND MATCH WINTER WX
ADVISORY UP WITH THAT FOR LUCE/SCHOOLCRAFT COUNTIES.  ACROSS NORTHWEST
LOWER...SIMILAR STORY THOUGH WINDS START OUT MORE AROUND 300 DEGREES
AND VEER AROUND TO 320-330 DURING THE AFTERNOON.  SIMILAR PARAMETERS AS
OVER LAKE SUPERIOR...BUT ADDITIONAL CONCERN HERE IS 850MB WINDS
FORECAST AROUND 50KT.  SOME QUESTION AS TO HOW STRONG WINDS AND LIMITED
RESIDENCE TIME WILL AFFECT NATURE OF LES.  SUSPECT THAT GIVEN THE
STRONGER WINDS...HIGHER TERRAIN AREAS SHOULD BE MORE PREDISPOSED TO
SEEING SOME HEAVIER SNOW BURSTS WITH ENHANCED UPSLOPE UVV...AGAIN LIKE
EASTERN UPPER SMALL LAKE-850MB THERMAL CONTRAST GIVING LOWER SNOW
TOTALS ON LOCAL GUIDANCE.  WILL TREND CURRENT FORECAST AMOUNTS UP A BIT
OVER HIGHER TERRAIN COUNTIES (UP TO 3 INCHES...LOCALLY HIGHER) AND
ALLOW LATER SHIFTS TO ASSESS HOW WELL ORGANIZED THIS MAY GET.  EXPECT
SOME AREAS MAY END UP WITH ADVISORY CRITERIA SNOWFALL IN THE END.  AS
FOR THE WINDS...STRONGEST GRADIENT ACTUALLY FORECAST TO ROTATE INTO THE
AREA ON BACKSIDE OF SURFACE LOW TONIGHT...STILL LOOKING UPSTREAM WINDS
ONLY A LITTLE STRONGER THAN CURRENTLY OVER AREA.  LAKE MICHIGAN
COUNTIES MOST LIKELY TO SEE WINDS APPROACH WARNING CRITERIA TONIGHT/
FRIDAY...SO WILL KEEP HIGH WIND WARNING UP THERE...TAPERING DOWN TO A
HIGH WIND ADVISORY FOR THE REST OF NORTHERN LOWER EXCEPT FOR CHEBOYGAN/
PRESQUE ISLE COUNTIES CLOSER TO WEAKER GRADIENT AREA TONIGHT AS SURFACE
LOW PULLS EAST.

FRIDAY NIGHT/SATURDAY/SATURDAY NIGHT...BOTH ETA/AVN FORECASTING STRONG
MID LEVEL DRYING ACROSS THE AREA FRIDAY EVENING...WITH INVERSION
HEIGHTS COMING DOWN AS WELL DESPITE COLDER 850MB TEMPERATURES FINALLY
FILTERING ACROSS THE LAKES.  WITH FLOW COMING AROUND MORE NORTH-
NORTHWEST WILL CONFINE MENTION OF SNOW SHOWERS TO AREAS WEST OF I-75
AND MENTION SOME LIGHT ACCUMULATIONS TO COVER ANY LINGERING HEAVIER
SNOW SHOWERS DURING THE EVENING.  ON SATURDAY...WILL CONTINUE TO TAPER
PRECIPITATION BACK TO JUST FLURRIES BY THE AFTERNOON AS INVERSION
HEIGHTS CONTINUE TO DROP TO NEAR 5K FEET.  EAST OF I-75 WILL ALLOW FOR
SOME SUNSHINE THOUGH WOULD EXPECT TO SEE A FAIR AMOUNT OF DIURNAL CU
POPS UP WITH 850MB TEMPERATURES NEAR -10C.  LOW LEVEL RIDGING/
ANTICYCLONIC FLOW BUILDS IN SATURDAY NIGHT WHICH SHOULD FURTHER BREAK
UP LAKE SC...SO WILL GO WITH PARTLY CLOUDY SKIES.

EXTENDED...PATTERN LONGER TERM REMAINS PROGRESSIVE AS HAS BEEN
ADVERTISED OVER THE PAST SEVERAL DAYS...WHICH WILL PULL THE GREAT LAKES
OUT OF ITS CURRENT COLD SPELL DURING THE BEGINNING OF THE WEEK.  SHORT
WAVE TROUGH STILL FORECAST TO CROSS THE CANADIAN CENTRAL PROVINCES
SUNDAY/MONDAY WITH MAIN HEIGHT FALLS PASSING NORTH OF LAKE SUPERIOR.
TAIL END OF ASSOCIATED COLD FRONT EXPECTED TO DROP INTO THE STATE FROM
THE NORTH ON MONDAY.  MOIST INFLOW CUT OFF BY SPRAWLING SURFACE HIGH
OVER THE SOUTHEAST...BUT BOTH MRF/CANADIAN MODELS SHOW A BAND OF
MOISTURE ALONG THE BOUNDARY AND SOME MINIMAL QPF...SO GIVEN THESE
TRENDS WILL ADD IN A CHANCE OF SHOWERS FOR MONDAY.  MRF CONTINUES TO
PUSH A SWATH OF MOISTURE/WAA INTO THE REGION ON TUESDAY...SLOWER THAN
ITS PREVIOUS RUN BUT APPEARS TO BE MORE EXTENSIVE IN COVERAGE.  STILL
THINK WE CAN GET AWAY WITH A DRY TUESDAY FORECAST BUT WILL PUT RAIN IN
NORTHERN LOWERS FORECAST FOR WEDNESDAY.  MODEL DIFFERENCES IN DEALING
WITH PACIFIC TROUGH COMING ONSHORE TUESDAY WILL HAVE AN EFFECT ON
THURSDAYS FORECAST...CANADIAN/ECMWF RUNS SPLIT THE TROUGH WITH ENERGY
HANGING BACK OVER THE SOUTHWEST...MRF IS MORE PROGRESSIVE IN KEEPING
TROUGH SOMEWHAT INTACT AS IT SWINGS THROUGH THE PLAINS AND INTO THE
GREAT LAKES THURSDAY.  WILL GO ALONG WITH THE LATTER IDEA FOR NOW AND
START THURSDAY OUT WITH A CHANCE FOR RAIN.  WILL KEEP FORECAST HIGHS
MAINLY IN THE 50S THROUGH MIDWEEK GIVEN THE RAIN CHANCES...EXCEPT
ACROSS EASTERN UPPER WHERE TEMPERATURES MAY INITIALLY BE HELD DOWN
DEPENDING ON NEW SNOW COVER.

COORDINATED WITH MQT/GRR/DTX.

.APX...WINTER WEATHER ADVISORY...OVERNIGHT/FRIDAY...MIZ008-015.
       HIGH WIND WARNING...TONIGHT/FRIDAY...MIZ016-019>021-025-031.
       HIGH WIND ADVISORY...TONIGHT/FRIDAY...MIZ022>024-026>030-032>036-
                                                   041-042.

JPB