Area Forecast Discussion
Issued by NWS Marquette, MI

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FXUS63 KMQT 251900
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
300 PM EDT WED MAR 25 2015

.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 300 PM EDT WED MAR 25 2015

A NEGATIVELY TILTED SHORTWAVE TROUGH ALOFT HAS MOVED INTO THE CWA
AHEAD OF AN UPPER TROUGH OVER CENTRAL CANADA. THE SHORTWAVE AND
ASSOCAITED 1002MB SFC LOW JUST N OF THE MN ARROWHEAD ARE RESULTING
IN AN AREA OF SNOW FROM NCENTRAL UPPER MI TO FAR NW WI AND NE MN.
THE SHORTWAVE/SFC LOW WILL MOVE TO NE OF LAKE SUPERIOR BY 00Z THU
AND MORE QUICKLY OFF TO THE NE LATER WED NIGHT. AS THE SYSTEM MOVE
NE...A TROUGH/COLD FRONT WILL SWEEP ACROSS THE CWA FROM THE NW
BETWEEN 03Z AND 12Z THU. 850MB TEMPS WILL DROP TO -15C BEHIND THE
FRONT BY 12Z THU...FALLING ANOTHER 2-3 DEGREES ON THU AS ANOTHER
SHORTWAVE IMMEDIATLY FOLLOWS THE FRONT AND THE UPPER TROUGH MOVES
OVERHEAD BY 00Z FRI.

THESE FEATURES WILL BE SUFFICIENT TO KEEP PRECIP /MOSTLY SNOW/ IN
THE FORECAST THROUGH THIS EVENING. MORE OF A TRANSITION TO LAKE
ENHANCED/UPSLOPE SNOW LATER THIS EVENING AND TONIGHT...CONTINUING
THROUGH THU. WITH THE RATHER COMPLICATED LIST OF ENERGY SOURCES
/SHORTWAVES...COLD FRONT...UPPER TROUGH/...EXACT SNOWFALL AMOUNTS
ARE A BIT MORE UNCERTAIN. THAT BEING SAID...DO NOT SEE A REASON WHY
NWRN UPPER MI /GENERALLY IRONWOOD TO COPPER HARBOR AND IN THE HIGHER
TERRAIN OF BARAGA COUNTY AROUND HERMAN/ WILL NOT SEE THE 3 INCH
SNOWFALL CRITERIA FOR A WINTER WEATHER ADVISORY. IN ADDITION TO THE
SNOWFALL...WINDS WILL INCREASE TONIGHT WITH GUSTS TO 30-35MPH NEAR
LAKE SUPERIOR AND OVER THE KEWEENAW TONIGHT INTO THU...LEADING TO
BLOWING SNOW...ESPECIALLY OVER THE KEWEENAW WHERE SNOWFALL WILL BE
BETTER. 24 HOUR AMOUNTS WILL BE GREATEST OVER THE HIGHER TERRAIN
NEAR LAKE SUPERIOR...WITH AMOUNTS OF 4-8 INCHES IN THE
AFOREMENTIONED NWRN UPPER MI AREAS AND 2-5 INCHES EAST OF BIG BAY.
HIGH TEMPS WILL RANGE FROM THE LOW-MID 20S OVER NWRN UPPER MI TO THE
MID 30S OVER THE FAR SCENTRAL. ADDITIONAL LIGHT SNOWFALL AMOUNTS ARE
EXPECTED THU NIGHT...SEE LONG TERM DISCUSSION FOR MORE DETAILS.

.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 546 AM EDT WED MAR 25 2015

WHILE THERE WILL BE OCCASIONAL DAYS OF ABOVE NORMAL TEMPS THRU THE
FIRST WEEK OF APR...IT APPEARS THE PATTERN ON THE WHOLE WILL SUPPORT
NORMAL TO BELOW NORMAL TEMPS WITH BLO NORMAL PROBABLY THE MORE
COMMON OUTCOME FOR THE MAJORITY OF DAYS OVER THE NEXT 2 WEEKS. PER
GFS AND GEM ENSEMBLES...THERE SHOULD BE SOME RETROGRESSION OF THE
NRN STREAM MEAN POSITIVE HEIGHT ANOMALY OVER WRN NAMERICA AND THE
MEAN NEGATIVE HEIGHT ANOMALY OVER ERN NAMERICA E OF HUDSON BAY. THIS
WILL RESULT IN MAINTENANCE OF A POOL OF COLD AIR ACROSS ERN CANADA
WHICH WILL SLOWLY SHIFT E TO ENCOMPASS MORE OF CANADA WITH TIME. FOR
UPPER MI...THE COLD AIR WILL BE TAPPED EASILY...AND THUS BLO NORMAL
TEMPS SHOULD BE THE MORE COMMON DAILY RESULT OVER THE NEXT 2 WEEKS.
IN CONTRAST TO THE VERY DRY SYNOPTIC PATTERN THAT HAS DOMINATED THE
UPPER LAKES AND UPPER MISSISSIPPI VALLEY SO FAR THIS YEAR...IT
APPEARS WE MAY BE HEADING FOR A PERIOD OF WETTER WEATHER OVER THE
NEXT 1 TO 2 WEEKS AS SRN STREAM ENERGY MOVES ACROSS THE CONUS AND
TAKES ADVANTAGE OF THE TEMP CONTRAST ACROSS THE MIDDLE OF THE
CONTINENT. PATTERN COULD SUPPORT MDT/HVY PCPN PRODUCING SYSTEMS E OF
THE ROCKIES...AND WITH THE POOL OF COLD AIR ACROSS CANADA...
POTENTIAL WILL ALSO BE THERE FOR SIGNIFICANT LATE SEASON SNOWFALLS
IN UPPER MI. OPERATIONAL GFS RUNS AND GEM ENSEMBLES OVER ROUGHLY THE
LAST WEEK HAVE CERTAINLY SHIFTED TO SUGGESTING A WETTER PATTERN THAN
WE`VE SEEN SO FAR THIS YEAR.

BEGINNING THU...IN THE WAKE OF SURFACE-850MB TROF DROPPING ACROSS
THE AREA TONIGHT...MUCH COLDER AIR WILL MOVE INTO THE UPPER LAKES ON
THU. 850MB TEMPS ACROSS LAKE SUPERIOR RANGING FROM -13C W TO -8C E
AT 12Z THU WILL FALL TO -15C TO -18C IN THE AFTN. THIS COLD AIR
COMBINED WITH DEEP MOISTURE AND WEAK FORCING UNDER MID LEVEL TROF
WILL LEAD TO LAKE ENHANCEMENT OFF LAKE SUPERIOR IN THE MORNING...AND
THEN A TRANSITION TOWARD PURE LES DURING THE AFTN AS DEEPER MOISTURE
DEPARTS. UNDER A GENERAL NORTHERLY LOW LEVEL WIND FLOW...HIGHEST
POPS/GREATEST SNOW ACCUMULATIONS WILL BE FOCUSED IN THE N WIND
FAVORED HIGHER TERRAIN AREAS DOWNWIND OF THE OPEN WATER ON LAKE
SUPERIOR (GOGEBIC/ONTONAGON COUNTIES AND FROM THE HURON MTNS OVER TO
WRN ALGER COUNTY. FARTHER E...HIGH ICE CONCENTRATION OVER ERN LAKE
SUPERIOR SHOULD HAVE A SIGNIFICANT NEGATIVE IMPACT ON LES E OF
MUNISING. DEEPENING AND DESCENDING DGZ WILL HELP TO FLUFF UP
SNOW/INCREASE SNOW TO WATER RATIOS. AT THIS POINT...SNOWFALL AMOUNTS
IN THE FAVORED AREAS ON THU SHOULD RANGE FROM 2-4 INCHES...LOCALLY
UP TO 5. IN ADDITION TO THE SNOW...THE NORTHERLY WINDS WILL BE GUSTY
TO 20-30KT...ESPECIALLY OVER THE KEWEENAW AND NCNTRL. WITH THE
FLUFFIER NATURE OF THE SNOW...THERE WILL BE SOME BLOWING SNOW.

850MB TEMPS FALL A LITTLE MORE THU NIGHT...BOTTOMING OUT AROUND
-20C. PASSING WEAK SHORTWAVE SHOULD GIVE LES A LITTLE BOOST THU
NIGHT THOUGH MODELS DON`T SHOW MUCH IMPACT ON MOISTURE OR INVERSION
HEIGHT WHICH IS INDICATED AT AROUND 5KFT. EXPECT ANOTHER INCH OR 2
OF SNOW IN THE N WIND FAVORED AREAS. SINCE DGZ OCCUPIES A GOOD
PORTION OF THE CONVECTIVE LAYER...WOULDN`T BE TOO SURPRISED TO SEE
LOCALIZED HIGHER AMOUNTS.

AS MIDLEVEL TROF SHIFTS E ON FRI...CENTER OF ARCTIC HIGH PRES WILL
DRIFT SE TO THE WESTERN GREAT LAKES REGION. INCREASED
DRYING/MODERATION OF AIR MASS AND THE DISRUPTIVE EFFECT OF LATE MAR
SOLAR HEATING WILL BRING AN END TO LIGHT LES DURING THE DAY FROM W
TO E. WITH THE HIGH DRIFTING ACROSS THE AREA FRI NIGHT...STAGE WILL
BE SET FOR A VERY COLD LATE MAR NIGHT UNDER CALM WIND AND DRY AIR
MASS (PRECIPITABLE WATER UNDER ONE-TENTH OF AN INCH). RECENT
ADDITION OF NEW SNOW ON THE GROUND IN MANY AREAS WILL FURTHER AID
THE COOLING. STRONGLY FAVORED THE COLDEST AVBL GUIDANCE...THE BIAS
CORRECTED CANADIAN GLOBAL MODEL WHICH OFTEN PERFORMS VERY WELL ON
EXCELLENT RADIATIONAL COOLING NIGHTS. MANY INTERIOR LOCATIONS SHOULD
FALL SUBZERO WITH TEENS BLO ZERO CERTAINLY POSSIBLE IN THE
TRADITIONAL COLDEST SPOTS. THE LOWEST TEMP OFF THE CANADIAN BIAS
CORRECTED IS -15F AT PEAVY FALLS.

SAT WILL BE SUNNY AND WARMER (MOVING CLOSER TO NORMAL FOR TEMPS...
ESPECIALLY W). SOUTHERLY WINDS WILL BEGIN TO INCREASE SAT...BUT MORE
SO SAT NIGHT DUE TO TIGHTENING PRES GRADIENT BTWN DEPARTING HIGH AND
SFC LOW PRES MOVING TO SRN MANITOBA. THAT LOW WILL BE ASSOCIATED
WITH A STRONG SHORTWAVE THAT WILL REACH THE UPPER LAKES ON SUN.
VIGOROUS DYNAMICS ASSOCIATED WITH 12HR 500MB HEIGHT FALLS OF 160-
200M...AND A PERIOD OF STRONG ISENTROPIC ASCENT WILL SUPPORT AT
LEAST A PERIOD OF PCPN LATE SAT NIGHT/SUN. GFS IS A GOOD 6HRS FASTER
THAN THE ECMWF/CANADIAN AND WOULD SPREAD PCPN ACROSS THE ENTIRE FCST
AREA OVERNIGHT SAT NIGHT WHEREAS THE ECMWF/CANADIAN HOLD PCPN OFF
UNTIL AFTER 12Z SUN. MIXING RATIOS OF 4G/KG ARE AVBL ON THE 295K SFC
(725-750MB)...SO THERE COULD BE A QUICK BURST OF DECENT SNOWFALL
DURING THE SHORT-LIVED PEAK ISENTROPIC ASCENT (1-2 INCHES OF SNOW).
WHILE THERE IS SOME CONCERN FOR ENOUGH WARMING TO CAUSE MIXED
PTYPES...BELIEVE STRENGTH OF UPWARD MOTION AND TIME OF DAY (ARRIVING
LATE NIGHT OR MORNING) WILL MAKE THIS INITIAL PERIOD OF PCPN ALL
SNOW. SYSTEM IS STILL FAR ENOUGH OUT TO ALLOW FOR IMPORTANT
ADJUSTMENTS IN FUTURE MODEL RUNS. IF SHORTWAVE TRACKS A BIT FARTHER
S AND UPPER MI ENDS UP ON THE CYCLONIC SIDE OF THE VORT TRACK...A
MORE SIGNIFICANT PCPN EVENT WILL OCCUR. WILL KEEP PCPN IN THE FCST
THRU SUN AND EVEN SUN NIGHT AS THERE ARE HINTS OF A SECONDARY WAVE
SWEEPING THROUGH THE AREA. AFTER THE INTIAL BURST OF SNOW WITH THE
STRONG ISENTROPIC ASCENT...ANY LIGHTER SNOW SUN SHOULD MIX WITH OR
EVEN CHANGE TO RAIN FOR A TIME UNDER DAYTIME HEATING...THEN CHANGE
BACK TO SNOW UNDER CAA SUN NIGHT. VIGOROUS SYSTEM SHOULD RESULT IN
WINDY CONDITIONS FOR MUCH OF THE AREA SUN.

DRY WEATHER WILL FOLLOW FOR MON...THEN WAA PATTERN AHEAD OF THE NEXT
SHORTWAVE APPROACHING THE NRN PLAINS MAY RESULT IN RAIN AND/OR SNOW
DEVELOPING TUE. WITH LOW CONFIDENCE ONLY SCHC POPS WERE UTILIZED
ACROSS THE N AND E.
&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 141 PM EDT WED MAR 25 2015

A LOW PRESSURE SYSTEM MOVING NORTH OF THE AREA WILL BRING SNOW TO
THE TAF SITES...ESPECIALLY KIWD AND KCMX...THIS AFTERNOON INTO THIS
EVENING. LAKE EFFECT WILL THEN INCREASE LATE THIS EVENING THROUGH
THURSDAY AS COLDER AIR MOVES IN ON N-NW WINDS. EXPECT SOME
IMPROVEMENT BETWEEN THE SNOW ASSOCIATED WITH THE LOW AND THE LAKE
EFFECT...BUT CONDITIONS WILL DEGRADE ONCE AGAIN THIS EVENING INTO
THURSDAY.
&&

.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 300 PM EDT WED MAR 25 2015

AN AREA OF LOW PRESSURE ACROSS N MN WILL SHIFT E ACROSS ONTARIO BY
THE END OF THE DAY WHILE DEEPENING. A LINGERING TROUGH ACROSS LAKE
SUPERIOR WILL EXIT TO THE SE THURSDAY MORNING. A FEW N GALE FORCE
GUSTS TO 35KTS WILL BE POSSIBLE OVER MAINLY N AND CENTRAL LAKE
SUPERIOR THURSDAY MORNING...BEFORE SLOWLY DIMINISHING THROUGH THE
DAY.

EXPECT A LOW OVER MANITOBA ON THURSDAY TO BRIEFLY SETTLE ACROSS THE
UPPER GREAT LAKES FRIDAY INTO EARLY SATURDAY...AND CONTINUE TO THE
OHIO VALLEY SATURDAY NIGHT. LOW PRESSURE STRETCHING FROM HUDSON BAY
TO S MANITOBA SATURDAY NIGHT WILL THEN SWING ACROSS CENTRAL ONTARIO
AND LAKE SUPERIOR SUNDAY AFTERNOON...AND INTO QUEBEC SUNDAY NIGHT.
ANOTHER PERIOD OF GUSTS OF 35 KTS TO NEAR 40KT GUSTS OF THE SW TO W
WILL BE POSSIBLE LATE SATURDAY NIGHT THROUGH SUNDAY...AND LINGER
OVER THE E HALF OF LAKE SUPERIOR OUT OF THE NW AT 35KTS SUNDAY NIGHT.
&&

.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&

$$

SHORT TERM...TITUS
LONG TERM...ROLFSON
AVIATION...TITUS
MARINE...TITUS



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