Area Forecast Discussion
Issued by NWS Gaylord, MI

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000
FXUS63 KAPX 291605
AFDAPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GAYLORD MI
1205 PM EDT SUN MAR 29 2015

.UPDATE...
ISSUED AT 1204 PM EDT SUN MAR 29 2015

12Z SURFACE ANALYSIS SHOWS A TIGHT PRESSURE GRADIENT BETWEEN A
1031MB HIGH CENTERED OVER WEST VIRGINIA...AND A WARM FRONT ACROSS
WESTERN MINNESOTA/EASTERN NEBRASKA WITH A NARROW WARM SECTOR AND A
COLD FRONT ACROSS NORTHWEST MINNESOTA/DAKOTAS.  WATER VAPOR IMAGERY
SHOWS A SHORT WAVE TROUGH OVER WESTERN MINNESOTA WITH A LEAD
ELONGATED VORTICITY AXIS STRETCHING FROM WESTERN LAKE SUPERIOR
SOUTHWARD INTO NORTHWEST WISCONSIN/NORTHWEST IOWA.  IT IS ALONG THIS
LEADING VORTICITY AXIS THAT A NARROW BAND OF PRECIPITATION WAS
PUSHING ACROSS WESTERN UPPER/WISCONSIN...AIDED BY ISENTROPIC ASCENT
AND WEAKER MID LEVEL STATIC STABILITY.  12Z APX/GRB SOUNDINGS WERE
STILL QUITE DRY BELOW 500MB (700/850MB DEW POINT DEPRESSIONS AROUND
30C AT APX).  PRECIPITATION AXIS IS FAIRLY NARROW AND IS FALLING AS
A MIX OF LIQUID AND FROZEN PRECIPITATION.

GRADUALLY OCCLUDING FRONT WILL SLIDE ACROSS WISCONSIN BUT WILL
PROBABLY STILL BE WEST OF THE FORECAST AREA AT EARLY EVENING.
PRECIPITATION TIMING LOOKS TO REACH THE WESTERN LOWER
SHORELINE/WESTERN MACKINAC COUNTY 17-18Z...THEN TOWARD THE I-75
CORRIDOR IN THE 18Z-19Z TIME FRAME...AND INTO NORTHEAST LOWER 19Z-
20Z.  NARROW AXIS OF PRECIPITATION IS A CONCERN FROM A QPF
STANDPOINT...BUT MINNESOTA SHORT WAVE TROUGH IS RAPIDLY CATCHING UP
TO THIS PRECIP BAND AND WATER VAPOR IMAGERY SHOWS UPWARD MOTION
FIELD ASSOCIATED WITH THIS WAVE STARTING TO INCREASE RADAR RETURNS
BEHIND THE PRECIP BAND ACROSS NORTHWEST WISCONSIN.  SO WIDTH OF THIS
BAND MAY INCREASE DURING THE MID/LATE AFTERNOON AS IT SPREADS ACROSS
LOWER MICHIGAN...SO A STRAIGHT EXTRAPOLATION OF UPSTREAM PRECIP
TRENDS MAY BE TOO SIMPLISTIC. STILL SUSPECT FORECAST QPF VALUES
MAY BE A LITTLE HIGH FOR THE 18Z-00Z TIME FRAME (E.G., AROUND 0.30
INCH ACROSS EASTERN UPPER)...AS SOME OF THE INITIAL PRECIP WILL GO
INTO SATURATING DRY LOWER LAYERS (SURFACE DEW POINTS IN THE SINGLE
DIGITS AND TEENS). SO WILL BACK THESE DOWN A LITTLE BASED ON
UPSTREAM PRECIP RATES...THOUGH ADMITTEDLY IN THE FACE OF BEEFY
PRECIP FORECASTS IN MESOSCALE GUIDANCE. THERE MAY STILL BE
SOMETHING OF A LULL IN THE PRECIP BEFORE SECONDARY AREA ON
BACKSIDE OF MAIN SHORT WAVE TROUGH ROTATES IN DURING THE
EVENING...WHICH WILL IMPACT THIS AS WELL. AS FOR PRECIP
TYPE...WITH TEMPERATURES ALREADY WARMING THROUGH THE 30S...PRECIP
WILL PROBABLY START AS RAIN RIGHT ON THE LEADING EDGE...BUT
EVAPORATIVE/MELTING INDUCED COOLING SHOULD DROP TEMPERATURES
ENOUGH TO SWITCH THINGS OVER THE SNOW ACROSS MUCH OF NORTHERN
LOWER EXCEPT PERHAPS EAST OF THE M-65 CORRIDOR IN NORTHEAST LOWER
IF SURFACE BASED WARM LAYER CAN HANG ON SINCE THIS AREA SHOULD
WARM UP THE MOST THIS AFTERNOON BEFORE CLOUDS THICKEN AND PRECIP
ARRIVES. MAY ALSO SEE PRECIP THIS EVENING TRANSITION BACK TO
LIQUID WITH THERMAL RIDGING ALONG OCCLUDED BOUNDARY. ADJUSTMENTS
TO P-TYPE AND QPF WILL ALSO BRING AFTERNOON SNOWFALL AMOUNTS DOWN
ACROSS EASTERN UPPER TO 1-2 INCHES FROM 2PM-8PM. WILL LEAVE ALL
HEADLINES ALONE AT THIS POINT. ALL-IN-ALL A REAL MESSY FORECAST TO
TRY AND GRID UP.

WINDS EXPECTED TO INCREASE EARLY THIS AFTERNOON WITH MIXING INTO A
40KT SOUTHWESTERLY LOW LEVEL JET.  MAY ALSO BE A BURST OF WIND WITH
ONSET OF PRECIPITATION DUE TO EVAPORATIVE COOLING WITHIN SHRINKING
SURFACE BASED DRY LAYER (GUSTS 40+ MPH).

&&

.NEAR TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 310 AM EDT SUN MAR 29 2015

HIGH IMPACT WEATHER POTENTIAL: WIND DRIVEN SNOW EVENT PRODUCING
TRAVEL IMPACTS LATER THIS AFTERNOON AND EVENING...ESPECIALLY
EASTERN UPPER AND HIGHER TERRAIN NRN LOWER. IN ADDITION...WIND
GUSTS OF 40-50 MPH POSSIBLE ALONG THE LAKE MICHIGAN COAST.

PATTERN SYNOPSIS/ANTICIPATED EVOLUTION: TWO SHORTWAVES MOVING
THROUGH THE UPPER MIDWEST...WITH THE EVENTUAL INTERACTION OF
THESE FEATURES RESULTING IN A LATE SEASON ACCUMULATING SNOW EVENT
FOR PARTS OF THE AREA LATER TODAY AND TONIGHT. DEVELOPING STRONG
LOW LEVEL KINEMATICS WITH 50+ KNOTS AT THE TOP OF MIXED
LAYER...WITH DOWNWARD MOMENTUM TRANSFER PRODUCING WIDESPREAD GUSTY
WINDS ACROSS THE AREA.

DETAILS: BUCKLE YOUR SEATBELTS AS IT COULD BE A WILD RIDE
WEATHERWISE ACROSS NORTHERN MICHIGAN OVER THE NEXT 24 HOURS.  RAPID
APPROACH OF LEAD UPSTREAM WAVE WILL GET EVERYTHING GOING...WITH MID
LEVEL QG SUPPORT ARRIVING WITH 60+ KNOT SOUTHWEST LOW LEVEL JET.
THIS WILL SURGE PWAT VALUES TOWARD 0.60 INCHES /TOP 10% CLIMO-WISE
FOR LATE MARCH/. INITIALLY DRY ANTECEDENT CONDITIONS WILL MOISTEN
QUICKLY WITH TOP DOWN SATURATION OCCURRING QUICKLY BETWEEN 18Z-
21Z FROM WEST-EAST ACROSS THE AREA. THOSE INITIALLY DRY
CONDITIONS WILL ALSO RESULT IN A RAPID COOLING OF THE BOUNDARY
LAYER THROUGH DYNAMIC COOLING OF THE COLUMN. SO PRECIPITATION MAY
START AS LIQUID BUT WILL QUICKLY MIX WITH/CHANGE TO SNOW OVER
INTERIOR AREAS. AS IS TYPICAL WITH LATE MARCH EVENTS...SNOWFALL
ACCUMS FOR THIS EVENT ARE QUITE A CHALLENGE AS YOU HAVE TO BALANCE
STRONG DYNAMICS AND EVAPORATIONAL COOLING WITH STILL RELATIVELY
WARM BOUNDARY LAYER TEMPS. WINDOW OF HEAVIEST SNOW RELATIVELY
NARROW /3-6 HOURS/ FROM MID AFTERNOON THROUGH EARLY EVENING.
SNOW/LIQUID RATIOS NOT THAT IMPRESSIVE GIVEN EXPECTED WARMER CLOUD
TEMPS...FLAKE FRAGMENTATION WITH STRONG WINDS AND AFTERNOON
ARRIVAL OF PCPN. SO PRECIPITATION INTENSITY WILL HAVE TO
COMPENSATE FOR LESS THAN IDEAL RATIOS/BOUNDARY LAYER TEMPS. BEST
CHANCE OF ACCUMULATING SNOW WILL BE OVER EASTERN UPPER AND THE
HIGHER TERRAIN OF NORTHERN LOWER...WHERE SEVERAL INCHES ARE
POSSIBLE. ELSEWHERE...WARMER SFC TEMPS WILL LIMIT ACCUMULATIONS
WITH MANY AREAS LIKELY LESS THAN ONE INCH.

WINDS MAY BE THE REAL STORY WITH 50-60KTS AT THE TOP OF THE MIXED
LAYER /WOW!/. MECHANICAL MIXING AND DOWNWARD MOMENTUM WILL
TRANSLATE AT LEAST SOME OF THESE WINDS TO THE SURFACE...WITH GUSTS
OF 40-50+ MPH LIKELY ALONG THE LAKE MICHIGAN COAST AND GUSTS TO
30+ MPH ELSEWHERE. STRONGEST WINDS MAY OCCUR JUST PRIOR TO MAIN
PRECIPITATION ARRIVING /VIRGA LOADING/ WITH MORE "STABLE"
CONDITIONS WITH THE PRECIPITATION. THE COMBINATION OF WIND AND
SNOW LIKELY TO CREATE VERY TREACHEROUS TRAVEL CONDITIONS FOR A
TIME WITH VISIBILITIES BELOW 1/2SM WITH BLOWING SNOW.

APPROACH OF SECONDARY WAVE AND MAINTENANCE OF DEEP MOISTURE EXPECTED
TO KEEP SNOWS GOING THROUGH AT LEAST THE FIRST HALF OF
TONIGHT...LIKELY MIXED WITH RAIN DURING THE EVENING.  LITTLE IN THE
WAY OF LAKE CONTRIBUTION WITH H8 TEMPS IN THE NEGATIVE SINGLE
DIGITS.  WINDS VEER WEST/NORTHWEST OVERNIGHT...LIKELY RESULTING IN
SOME FORCED UPSLOPE ENHANCEMENT TO PRECIPITATION INTO THE HIGHER
TERRAIN.

HEADLINES:  WIND ADVISORY ALONG THE LAKE MICHIGAN COAST THROUGH
EARLY EVENING WITH WIND GUSTS TO 40-50+ MPH POSSIBLE. WINTER
WEATHER ADVISORY EASTERN UPPER AND A HANDFUL OF COUNTIES /OTSEGO-
ANTRIM-KALKASKA-CRAWFORD/ CENTERED AROUND THE HIGHER TERRAIN FROM
EARLY AFTERNOON THROUGH MIDNIGHT.

&&

.SHORT TERM...(MONDAY THROUGH TUESDAY NIGHT)
ISSUED AT 310 AM EDT SUN MAR 29 2015

HIGH IMPACT WEATHER POTENTIAL: SNEAKY POSSIBILITY FOR A NARROW BAND
OF ACCUMULATING SNOW TO AFFECT AT LEAST A PORTION OF NORTHERN
MICHIGAN MONDAY NIGHT INTO TUESDAY MORNING. PLACEMENT OF THIS
FEATURE REMAINS A FORMIDABLE CHALLENGE.

TIME TO BREAK OUT THE DART BOARD! LOTS OF UNCERTAINTY REMAINS WITH
REGARD TO THE POTENTIAL FOR A RATHER NARROW BAND OF FGEN-DRIVEN SNOW
TO IMPACT AT LEAST A PORTION OF THE AREA LATER MONDAY NIGHT INTO
TUESDAY. UNFORTUNATELY...SHOULD THIS FEATURE COME TO FRUITION...
THERE COULD BE A CORRIDOR OF SEVERAL INCHES OF HEAVY SNOW FALLING IN
ONLY A FEW HOURS TOWARD THE MORNING COMMUTE TUESDAY...BUT AS ALLUDED
TO MANY TIMES RECENTLY...CONFIDENCE IS AT THE BOTTOM OF THE BARREL
WHEN IT COMES TO PLACING SAID SNOW BAND.

PRIOR TO HAVING TO DEAL WITH THAT...THE START OF THE WORK WEEK ON
MONDAY SHOULD OFFER A CONTINUATION OF RATHER DREARY WEATHER...AS WE
CYCLE ANOTHER FLEETING BOUT OF COOLER AIR ALOFT (H8 TEMPS NEAR -10C)
OVERHEAD...ON THE TAIL END OF SHARPER UPPER TROUGHING WORKING
THROUGH THE NORTHEAST CONUS. AIRMASS IS MARGINAL FOR A LAKE
RESPONSE...BUT DEEPER MOISTURE PLUME UP TO AROUND 800MB CROSSING THE
AREA THROUGH MIDDAY SHOULD PROVE SUFFICIENT TO CONTINUE SOME LIGHT
SNOW SHOWERS OR FLURRIES... PARTICULARLY HIGHER TERRAIN AREAS WITH
AN UPSLOPE NORTHWEST FLOW COMPONENT. ANY FLAKES SHOULD END BY MIDDAY
AS WE SQUEEZE DRIER AIR INTO THE AREA AND THE FLOW TURNS
INCREASINGLY ANTICYCLONIC...WITH LIKELY SOME PEAKS OF AFTERNOON
SUNSHINE AS MOISTURE REALLY THINS.

WITH THAT OUT OF THE WAY...OF COURSE WE TURN OUR ATTENTION TO THE
FINAL DAY OF THE MONTH. FAIRLY ENERGETIC SHORTWAVE JUST COMING
ASHORE INTO SOUTHERN BRITISH COLOMBIA TONIGHT WILL RIDE UP AND OVER
THE WESTERN RIDGE AND MAKE A BEELINE TOWARD THE GREAT LAKES BY
MONDAY NIGHT. UNFORTUNATELY...THIS FEATURE REMAINS POORLY SAMPLED AS
IT HAS YET TO REALLY COME TOGETHER...RESULTING IN POOR RUN-TO-RUN
CONSISTENCY REGARDING WHAT SHOULD BE A DECENT LOW/MID LEVEL FGEN
RESPONSE AS IT DIVES IN OUR DIRECTION. AMERICAN MODELS HAVE FEATURED
A MORE NORTHERLY SCENARIO RECENTLY...WITH GLOBAL SOLUTIONS MORE
TOWARD CENTRAL/SOUTHERN LOWER MICHIGAN. OF COURSE...VARIOUS ENSEMBLE
MEMBERS ARE ALL OVER THE PLACE AS WELL...THOUGH THE MEAN DOES LEAN
SLIGHTLY TOWARD THE MORE NORTHERLY SCENARIOS.

HAVE TO SAY THAT MY GUT FEELING IS ACTUALLY A COMPROMISE OF
SOLUTIONS...FAVORING A BAND OF ENHANCED FORCING/PRECIP SLIDING
THROUGH PORTIONS OF NORTHERN LOWER...ALL WHILE MARKEDLY DRIER LOW
LEVEL AIR AND DOWNWARD BRANCH OF THE FGEN CIRCULATION LIKELY KEEP
EASTERN UPPER ON THE DRY SIDE. MOISTURE AGAIN IS RESPECTABLE WITH AN
AXIS OF PWAT VALUES NEARBY... AND STEEP MID LEVEL LAPSE RATES MAY
EVEN ADD A SLIGHT CONVECTIVE COMPONENT TO THE ALREADY STRONG
FRONTOGENETIC RESPONSE. ALL TOLD...THIS SETUP HAS THE POTENTIAL TO
DELIVER SOME LOCALIZED QUITE HEAVY SNOW AMOUNTS IN A SMALL
CORRIDOR...BUT AGAIN...PLACEMENT WILL BE KEY. NEED TO KEEP A VERY
CLOSE EYE ON THIS!

HIGH PRESSURE RETURNS WITH QUIET WEATHER LATER TUESDAY AFTERNOON
INTO TUESDAY NIGHT. COULD BE SOME SNEAKY QUITE COLD READINGS SHOULD
THERE BE ANY FRESH SNOW COVER IN SPOTS...JUST IN TIME OF COURSE TO
WELCOME THE MONTH OF APRIL.

&&

.LONG TERM...(WEDNESDAY THROUGH SATURDAY)
ISSUED AT 310 AM EDT SUN MAR 29 2015

ONE WORD TO DESCRIBE THE WEATHER PATTERN HEADING INTO THE FIRST WEEK
OF APRIL: ACTIVE! STARTING TO SEE SOME NICE CONSENSUS DEVELOP WITH
OUR MIDWEEK SYSTEM...AS ANOTHER STRONGER NORTHERN TIER SHORTWAVE
ROLLS OUT OF THE NORTHERN ROCKIES ON WEDNESDAY...SHEARING OUT AS IT
TRACKS INTO THE FAR NORTHERN LAKES LATER THURSDAY. GUIDANCE TRENDS
ARE ENCOURAGING...WITH ALL FEATURING A STRONGER LOW PASSING INTO
CENTRAL/EASTERN ONTARIO ON THURSDAY...WITH A WARM FRONT CLEARING THE
AREA WELL PRIOR TO THAT ON WEDNESDAY. PLENTY OF SPRING-LIKE WARMTH
ALOFT SHOULD FLOOD INTO THE WARM SECTOR...BUT MAY TAKE SOME TIME TO
BE REALIZED AT THE SURFACE INITIALLY ON WEDNESDAY. STILL...IT DOES
APPEAR INCREASINGLY LIKELY THAT WE WILL SEE A WELL-DESERVED STINT OF
MORE SPRING-LIKE TEMPERATURES WEDNESDAY NIGHT INTO THURSDAY...BEFORE
AN APPROACHING COLD FRONT YIELDS OUR NEXT CHANCE FOR SHOWERS DURING
THIS PERIOD. TIMING IS OF COURSE DIFFICULT...WHICH WILL ALSO HAVE AN
IMPACT ON JUST HOW WARM WE CAN GET ON THURSDAY (ECMWF MUCH SLOWER
THAN OTHERS WITH THE FRONTAL PASSAGE).

AFTER THAT...CONFIDENCE AGAIN FALLS OFF THE TABLE HEADING TOWARD
EASTER WEEKEND. ECMWF/GGEM HAVE BEEN RATHER INSISTENT ON DRIVING A
RATHER AMPLIFIED SYSTEM INTO THE GREAT LAKES FOR SEVERAL DAYS NOW
WHILE THE GFS FLOUNDERS FROM RUN TO RUN. THE SIGNAL IS CERTAINLY
THERE FOR SOMETHING IMPACTFUL TOWARD THIS PERIOD...WITH MAYBE
CONVECTION AND/OR SNOW PENDING THE EVENTUAL TRACK OF ANY SYSTEM. FOR
NOW...CHANCES FOR SHOWERS WILL HAVE TO DO THE TRICK BUT WILL ALSO BE
WATCHING THE PERIOD CLOSELY.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 642 AM EDT SUN MAR 29 2015

VFR CONDITIONS WILL PERSIST THIS MORNING...WITH CLOUDS GRADUALLY
LOWERING WITH THE APPROACH OF A STRONG COLD FRONT/SHORT WAVE. LLWS
WILL PERSIST ALONG THE LAKE MICHIGAN COAST (PLN-TVC-MBL) THROUGH
14Z. STRONG S/SW WINDS WILL BEGIN TO REACH THE SURFACE BY MID-
MORNING. CONDITIONS WILL RAPIDLY DETERIORATE TO MVFR/IFR THIS
AFTERNOON AS A WELL DEFINED BAND OF RAIN/SNOW ARRIVES AT OUR NW
LWR MICHIGAN TAF SITES BY 19Z...MARCHING EASTWARD TO NE LWR (APN)
BY 21Z. S/SW WINDS GUSTING 30 TO 35 KTS MAY CAUSE AREAS OF REDUCED
VSBYS WITH BLOWING SNOW. WINDS VEER TO THE NW THIS EVENING BUT
CONTINUE TO BE GUSTY UP TO 30KTS. CIGS/VSBYS WILL IMPROVE LATER
TONIGHT AS THE COLD FRONT PUSHES EAST AND DRIER AIR BEGINS TO MOVE
INTO THE AREA.


&&

.APX WATCHES/WARNINGS/ADVISORIES...
MI...WINTER WEATHER ADVISORY UNTIL MIDNIGHT EDT TONIGHT FOR MIZ008-
     015-021-022-027-028.

     WIND ADVISORY UNTIL 6 PM EDT THIS EVENING FOR MIZ016-019-020-025-
     026-031-032.

LH...NONE.
LM...NONE.
LS...GALE WARNING UNTIL 6 AM EDT MONDAY FOR LSZ321-322.

&&

$$

UPDATE...JPB
NEAR TERM...KEYSOR
SHORT TERM...LAWRENCE
LONG TERM...LAWRENCE
AVIATION...KEYSOR



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