Area Forecast Discussion
Issued by NWS Marquette, MI

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000
FXUS63 KMQT 271119
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
619 AM EST FRI FEB 27 2015

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 402 AM EST FRI FEB 27 2015

00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW A NW FLOW ALOFT
OVER THE UPR GREAT LKS TO THE SW OF CLOSED H5 LO OVER NRN QUEBEC.
SHRTWV RDG AXIS STRETCHING FM THE NRN PLAINS INTO NW ONTARIO IS
SUPPORTING A SFC HI PRES STRETCHING FM THE NRN PLAINS INTO IOWA. UPR
MI IS DOMINATED BY A DRY WNW LLVL FLOW E OF THIS HI CENTER /00Z
PWATS UPSTREAM ARE GENERALLY 0.05 TO 0.10 INCH...NO MORE THAN 50 PCT
OF NORMAL/. COMBINATION OF THE DRYNESS OF THE UPSTREAM AIRMASS...00Z
INL AND YPL RAOBS SHOW AN INVERTED V T/TD PROFILE BLO SUBSIDENCE
INVRN NEAR H9...AND EXTENSIVE ICE COVER OVER LK SUP HAS GREATLY
DIMINISHED THE LES. IN FACT...IR STLT IMAGERY SHOWS ONLY PATCHY LK
CLDS STREAMING INTO AREAS E OF MUNISING. 00Z H85 TEMPS OVER THE AREA
RANGE FM -23C AT GRB TO -19C AT INL/YPL AND THEN UP TO -16C AT THE
PAS MANITOBA. UNDER THE MOCLR SKIES/DRY ARCTIC AIRMASS...TEMPS HAVE
FALLEN WELL BLO ZERO OVER THE INTERIOR AND AS LO AS -25F TO -30F AT
THE MORE SHELTERED RURAL SPOTS. WINDS ARE STIRRING A BIT MORE NEAR
LK SUP UNDER A TIGHTER PRES GRADIENT...AND SOME OF THE MORE EXPOSED
LOCATIONS THERE ARE INDICATING WIND CHILLS AS LO AS -25F.

MAIN FCST CONCERNS THRU TNGT WL BE ON TEMPS. OPTED TO ISSUE AN SPS
TO COVER WIND CHILLS NEAR ADVY CRITERIA AT THE MORE EXPOSED
LOCATIONS NEAR LK SUP THIS MRNG.

TODAY...AS SHRTWV RDG TO THE NW SLIDES TO THE SE...SFC HI PRES
CENTER IS FCST TO SHIFT TO INDIANA/ILLINOIS BY 00Z SAT. THE
COMBINATION OF ONGOING SUBSIDENCE AHEAD OF THE SHRTWV RDG AND SOME
WAA AS THE SFC-H925 FLOW BACKS TO THE WSW...IS FCST TO RAISE H85
TEMPS UP TO -16 TO -17C BY THE END OF THE DAY. GIVEN ABSENCE OF MUCH
DIURNAL CU UPSTREAM YDAY AND LARGER SCALE SUBSIDENCE/WRMG AT H85...
SUSPECT THERE WL ONLY BE SOME SCT DIURNAL CLDS OVER THE INTERIOR
THIS AFTN. AS THE FLOW BACKS...LINGERING LK CLDS/ANY FLURRIES E OF
MUNISING THIS MRNG SHOULD SHIFT OUT OVER LK SUP IN THE AFTN. WITH A
GOOD DEAL OF SUNSHINE...GOING FCST HI TEMPS RECOVERING INTO THE
TEENS APPEAR TO BE ON TRACK.

TNGT...SFC HI PRES IS FCST TO SLIDE INTO THE MID ATLANTIC STATES BY
12Z SUN...WITH STEADY WSW WIND REMAINING IN PLACE UNDER THE TIGHT
PRES GRADIENT TO THE NW OF THIS FEATURE. ALOFT...UPR MI BE UNDER
CONTINUED SUBSIDENCE AHEAD OF ANOTHER SHRTWV RDG APRCHG FM THE W.
WITH A CONTINUED SLOW WARMING OF THE H85 TEMPS...AN ABSENCE OF ANY
SGNFT LLVL MSTR INFLOW AND GENERALY ACYC NATURE OF THE W FLOW...LK
CLDS OVER THE KEWEENAW SHOULD BE SCT AT BEST. ANY LK CLDS/LES OVER
THE E HALF OF THE LK SHOULD REMAIN OFFSHORE. PWAT IS FCST TO BE AOB
0.10 INCH...SO TENDED TO GO AOB THE LO END OF GUIDANCE FOR MIN TEMPS
/AS IS OBSVD THIS MRNG/ IN AREAS AWAY FM LK SUP...WHERE A STEADIER
WIND SHOULD LIMIT THE DIURNAL TEMP DROP.

.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 402 AM EST FRI FEB 27 2015

SATURDAY INTO SATURDAY NIGHT...A BROAD SURFACE HIGH PRESSURE SYSTEM
OVER MUCH OF THE GREAT LAKES REGION WILL REMAIN IN PLACE THROUGH THE
DAY SATURDAY. THIS WILL KEEP FAIRLY DRY AIR IN PLACE ALLOWING MOST
AREAS OF THE U.P. TO SEE SUNNY SKIES THROUGH THE DAY SATURDAY.  BY
SATURDAY NIGHT...THE HIGH PRESSURE CENTER WILL SHIFT EASTWARD
STRETCHING FROM THE NORTHEAST U.S. SOUTHWARD ALONG THE EASTERN
SEABOARD. AT THIS HAPPENS...A WEAK SURFACE TROUGH/COLD FRONT WILL
APPROACH THE AREA FROM THE WEST.  OVERALL MOISTURE APPEARS TO BE
LIMITED AND FOCUSED MAINLY TO THE SOUTH OF THE U.P. THEREFORE...ONLY
EXPECTING AN INCREASE IN CLOUD COVER SATURDAY NIGHT WITH ONLY A
SMALL CHANCE OF LIGHT SNOW ACROSS THE U.P. WITH LIMITED/WEAK FORCING.

SUNDAY THROUGH MONDAY...THE SURFACE TROUGH/WEAK COLD FRONT WILL
CONTINUE TO SHIFT EASTWARD AND PASS THROUGH THE UPPER PENINSULA
THROUGH THE DAY SUNDAY. AGAIN...MOISTURE WILL BE LIMITED ALONG THE
FRONT WITH CONTINUED WEAK FORCING. ONLY LIGHT SNOW IS EXPECTED
THROUGH THE DAY SUNDAY. BEHIND THE FRONT...AN UPPER LEVEL 500MB
TROUGH IS POISED TO SWING ACROSS THE U.P. SUNDAY NIGHT. AS THIS
HAPPENS...ENOUGH MOISTURE WILL REMAIN IN PLACE WITH VERY SLIGHT
ADDITIONAL MOISTURE ADDED FROM THE ICE COVER LAKE SUPERIOR TO ALLOW
A CHANCE OF LAKE EFFECT SNOW SHOWERS TO DEVELOP FOR WEST TO
NORTHWEST WIND FAVORED LOCATIONS.  DELTA T VALUES WILL BE SUFFICIENT
FOR LAKE EFFECT WITH THE TROUGH AXIS SLIDING ACROSS...BUT LAKE
EFFECT INTENSITY WILL BE LIMITED TO AREAS THAT ANY BREAKS IN THE ICE
COVER OCCURS. ANY LAKE EFFECT THAT IS ABLE TO DEVELOP SUNDAY NIGHT
WILL BE SHORT LIVED AS MUCH DRIER AIR AND HIGH PRESSURE AT THE
SURFACE AND SLIGHT RIDGING ALOFT TO PUSH INTO THE UPPER GREAT LAKES
REGION DURING THE DAY MONDAY. THIS WILL FOR MAINLY SUNNY SKIES
DURING THE DAY MONDAY.

MONDAY NIGHT THROUGH WEDNESDAY...THE AFOREMENTIONED HIGH PRESSURE
SYSTEM WILL SHIFT TO THE LOWER GREAT LAKES...THEN THE EASTERN
SEABOARD MONDAY NIGHT.  THIS WILL ALLOW A MORE MOIST SOUTHERLY FLOW
TO DEVELOP ON THE BACK SIDE OF THE HIGH.  AT THE SAME TIME...A LOW
PRESSURE SYSTEM IS PROGGED TO DEVELOP OVER THE FOUR CORNERS REGION
OF THE U.S. ADDITIONALLY...ANOTHER STRONGER WAVE OF ENERGY IS
PROGGED TO PUSH ACROSS CENTRAL CANADA AND WORK TOWARD THE JAMES BAY
AREA.  THERE ARE MODEL DIFFERENCES WITH THE PHASING OF THE TWO
SYSTEMS.  THE 18Z/26 00Z/27 GFS IS MORE PROGRESSIVE WITH BOTH
SYSTEMS AND THE PHASING OF THE SYSTEMS. THIS WOULD PUSH SNOW INTO
THE AREA AS EARLY AS MONDAY EVENING ON ISENTROPIC UPGLIDE AND
INCREASED MOISTURE IN THE AREA. THE EC 12/26 00Z/27 IS MUCH SLOWER
WITH THE PHASING...KEEPING THE PRECIPITATION OUT OF THE AREA UNTIL
LATE MONDAY NIGHT INTO TUESDAY MORNING. THE BEST CHANCES GIVEN THE
OVERLAP OF THE TWO MODEL SOLUTIONS WOULD BE TUESDAY AFTERNOON INTO
TUESDAY NIGHT...ESPECIALLY FOR THE EAST HALF OF THE U.P. AT THIS
POINT...WILL STICK WITH CHANCE POPS AT LEAST UNTIL THE SYSTEM IS
SAMPLED BETTER OVER THE NEXT FEW DAYS.

WEDNESDAY NIGHT AND THURSDAY...BOTH THE EC AND GFS AGREE ON AN UPPER
LEVEL TROUGH AXIS ALONG WITH DEEPER MOISTURE LINGERING ACROSS THE
AREA DURING THIS TIME PERIOD. THE COLDER TEMPERATURES ALOFT ALONG
WITH ANY ADDITIONAL MOISTURE OFF LAKE SUPERIOR WILL ALLOW FOR LAKE
EFFECT SNOW CHANCES. AGAIN...THE EXACT LOCATION ALONG WITH INTENSITY
WILL BE LARGELY TIED TO ANY BREAKS IN THE ICE COVER ON LAKE
SUPERIOR. THE FAVORED LOCATIONS BASED SOLELY ON WIND WOULD BE FOR
THE WEST TO WEST NORTHWEST WIND FAVORED SNOW BELTS. GENERALLY...ANY
LAKE EFFECT SNOW SHOULD REMAIN FAIRLY LIGHT.
&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 618 AM EST FRI FEB 27 2015

WITH DRY HI PRES DOMINATING...EXPECT VFR CONDITIONS TO PREDOMINATE
AT THE TAF SITES THIS FCST PERIOD. NOT OUT OF THE QUESTION THERE
COULD BE SOME MVFR CIGS AS DIURNAL CU/SC DEVELOP LATE THIS MRNG/
AFTN...BUT ABSENCE OF THESE CLDS UPSTREAM YDAY...RELATIVELY LO
SUBSIDENCE INVRN BASE AND ICE COVER ON LK SUP THAT WL RESTRICT
MOISTENING OF THE AIRMASS INDICATE THE CHC IS TOO LO TO INCLUDE IN
THE TAFS.
&&

.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 402 AM EST FRI FEB 27 2015

EXPECT WINDS TO BE UNDER 30 KTS THIS FORECAST PERIOD. LAKE SUPERIOR
IS MAINLY ICE COVERED THIS MORNING. ALTHOUGH SHIFTING WINDS UP TO 20
TO 25 KTS ACCOMPANYING THE PASSAGE OF DISTURBANCES THRU THE UPPER
LAKES MAY CAUSE HOLES TO OPEN IN THE ICE FROM TIME TO TIME...A
CONTINUED DOMINANCE OF ARCTIC AIR WILL MAINTAIN AN OVERALL EXTENSIVE
ICE COVER.
&&

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

$$

SHORT TERM...KC
LONG TERM...KEC
AVIATION...KC
MARINE...KC



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