Area Forecast Discussion
Issued by NWS Marquette, MI

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000
FXUS63 KMQT 120916
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
516 AM EDT SAT APR 12 2014

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 516 AM EDT SAT APR 12 2014

WV IMAGERY AND RUC ANALYSIS INDICATED A SHORTWAVE TROUGH OVER NORTH
DAKOTA IN ZONAL MID/UPPER LEVEL FLOW ACROSS THE NRN CONUS. AT THE
SFC...LOW PRES WAS LOCATED OVER SE SD WITH A WARM FRONT INTO NRN IA.
FARTHER NORTH...A COLD FRONT EXTENDED FROM CNTRL LAKE SUPERIOR
INTO NE SD BORDERING ARCTIC HIGH PRES BUILDING THROUGH NRN OTARIO.
SHRA FROM CNTRL MN AND NW WI INTO SW MN AND NRN IA WAS SUPPORTED BY
STRONG 295K-300K ISENTROPIC LIFT AHEAD OF THE WARM FRONT. THERE WAS
ALSO ENOUGH CONVECTIVE INSTABILITY TO SUPPORT ISOLD TSRA FROM ERN SD
INTO NW IA.

TODAY...RADAR/SATELLITE TRENDS AND MODELS SUGGEST THAT THE AREA OF
PCPN WILL CONTINUE TO EXPAND TO THE ENE INTO UPPER MI AS THE BAND OF
ISENTROPIC LIFT MOVES THROUGH AIDED BY UPPER LEVEL DIV ASSOCIATED
WITH THE RIGHT ENTRANCE OF THE 250-300 JET LIFTING INTO NRN ONTARIO
MOVES THROUGH. THE HEAVIEST PCPN IS EXPECTED MAINLY ACROSS THE SRN
HALF OF THE CWA...CLOSEST TO THE 850-700 TEMP GRADIENT...WITH
OVERALL QPF VALUES IN THE 0.30 TO 0.60 INCH RANGE. FCST MUCAPE
VALUES TO AROUND 400 J/KG ALSO SUPPORT THE POTENTIAL FOR TSRA OVER
THE SOUTH THIS AFTERNOON AND EVENING.

THE MAIN FCST QUESTIONS WILL BE PCPN TYPE AND SNOWFALL AMOUNTS. THE
NAM AND REGIONAL GEM LOW LEVEL THICKNESS AND WET-BULB ZERO HEIGHTS
SUGGEST THAT LOW LEVEL TEMPS WILL BE LOW ENOUGH AIDED BY EVAPORATIVE
COOLING FOR A PERIOD OF SNOW OVER THE NW HALF OF UPPER MI LATE THIS
MORNING INTO EARLY AFTERNOON THAT WOULD GRADUALLY CHANGE OVER TO
RAIN OR DRIZZLE AS WARMER AIR IN THE 900-750 MB LAYER MOVES IN ALONG
WITH MID LEVEL DRYING. THE PCPN INTENSITY MAY BE HIGH ENOUGH SO THAT
A COUPLE INCHES OF WET SNOW MAY ACCUMULATE EVEN WITH AIR TEMPS INTO
THE MID 30S. FORTUNATELY...THE AIR AND GROUND TEMPS SHOULD REMAIN
HIGH ENOUGH TO LIMIT ANY POTENTIAL FOR FREEZING PCPN AS THE SNOW
CHANGES OVER TO RAIN.

TONIGHT...THE PCPN WILL TAPER OFF FROM WEST TO EAST IN THE EVENING AS THE
SUPPORTING DYNAMICS EXIT THE AREA. HOWEVER...THERE MAY STILL BE SOME
LINGERING LIGHT RAIN OR DRIZZLE...ESPECIALLY IN LOCATIONS FAVORED BY
UPSLOP ERLY FLOW.

.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 505 AM EDT SAT APR 12 2014

UNSEASONABLY COOL AIR WILL BE TRAPPED ACROSS UPPER MI THROUGH AT
LEAST THE MIDDLE OF THE NEXT WORK WEEK. THE MODEL SPREAD IS ROUGHLY
10F FROM TUESDAY THROUGH FRIDAY FOR MAX TEMPS...WITH OUR OFFICIAL
FCST BOUNCING FROM ALL ALONG THE SPECTRUM

THE WEATHER MAP AT 12Z SUNDAY WILL SHOW A HIGH AMPLITUDE 500MB RIDGE
ACROSS THE W COAST...AND THE SE U.S. IN THE MIDDLE A TROUGH WILL
EXTEND FROM HUDSON BAY THROUGH S CENTRAL CANADA AND THROUGH WY AND
CO. THE 500MB LOW WILL CONTINUE TO BE REINFORCED OVER HUDSON BAY
SUNDAY NIGHT...AND DIG ACROSS FAR N ONTARIO MONDAY THROUGH TUESDAY.
THIS WILL RESULT IN A RETURN OF MUCH COOLER THAN NORMAL
TEMPERATURES. NORMAL HIGH TEMPERATURES OVER MUCH OF THE CWA ARE NOW
IN THE MID 40S.

LOW PRESSURE STRETCHING FROM OK THROUGH NE AND LOWER MI AT 12Z
SUNDAY WILL SLOWLY PUSH TO LOWER MI AND FAR S QUEBEC BY 12Z
MONDAY...AND DEEPEN AS IT MOVES OVER FAR E CANADA MONDAY NIGHT.
ACROSS THE UPPER GREAT LAKES...PLENTY OF COLD AIR WILL FILTER IN
BEHIND THE LOW. NW WIND GUSTS MONDAY AFTERNOON MAY TOP OUT 20 TO
NEAR 30KTS...STRONGEST ACROSS THE KEWEENAW PENINSULA AND E ALONG THE
LAKE SUPERIOR SHORELINE.

THE COLDEST DAY /TUESDAY/ WILL SEE TEMPS STRUGGLING TO GET TO THE
FREEZING MARK DURING THE DAYTIME HOURS AS COLD HIGH PRESSURE SETTLES
IN AT THE SFC...WITH NW FLOW REMAINING ALOFT. THE COLD TEMPERATURES
WILL HAVE A SIGNIFICANT IMPACT ON SNOWMELT AND RIVER LEVELS THROUGH
AT LEAST THE FIRST HALF OF THE WORK WEEK...SLOWING DOWN THE WHOLE
PROCESS. LOOK FOR 850MB TEMPS TO FALL BELOW -8C OVER THE W HALF BY
12Z WEDNESDAY...CHANGING ANY LINGERING LIGHT PRECIP TO ALL SNOW/SNOW
SHOWERS.

THE LATTER HALF OF THE WORK WEEK WILL BE MORE JUMBLED...WITH THE A
GENERAL 500MB TROUGH OVER S CENTRAL CANADA AND THE N PLAINS STATES
WEDNESDAY NIGHT. THE NAM LOOKS TO BE MUCH DEEPER WITH THE S EXTENDED
OF THE LOW FOR TH-FRI. WILL CONTINUE TO GO MIDDLE OF THE ROAD FOR
THIS LONGER TERM PERIOD. THE MID WEEK SFC HIGH WILL BE REPLACED BY
YET ANOTHER INVERTED TROUGH SETTING UP FROM THE S PLAINS THROUGH NM
AND WI AT 00Z THURSDAY. THE LATEST ECMWF HAS THE SFC LOW TRACKING
ACROSS UPPER MI THURSDAY AFTERNOON WHILE THE GFS DOESN/T HAVE IT
CROSSING UPPER MI UNTIL FRIDAY NIGHT/SATURDAY MORNING. WILL NOT JUMP
INTO THE WEEDS OF THE EXTENDED FCST AT THIS POINT DUE TO THE
UNCERTAINTY.
&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 122 AM EDT SAT APR 12 2014

ALTHOUGH MID/HI CLDS WL BE THICKENING EARLY THIS MRNG...EXPECT
PREDOMINANT VFR CONDITIONS AND LIGHT WINDS THRU SUNRISE WITH WEAK
RDG OF HI PRES AND LLVL DRY AIR IN PLACE. BUT AS A LO PRES TAKING
SHAPE IN THE NORTHERN PLAINS MOVES INTO THE UPR MIDWEST THIS
AFTN...WDSPRD PCPN WL DVLP W-E OVER UPR MI WITH THE ARRIVAL OF
DEEPER MSTR AND DYNAMIC SUPPORT. WHERE THE AIRMASS IS COLD ENUF FOR
MAINLY SN AND THE LLVL ESE WIND WL UPSLOPE AT CMX AND SAW...PLAN ON
LIFR CONDITIONS FM LATE THIS MRNG THRU MUCH OF THE AFTN. BUT EVEN AT
IWD WHERE THE PCPN WL BE LIGHTER AND MIXED WITH RA...IFR CIGS ARE
FCST. ALTHOUGH THE STEADY PCPN WL END BY 00Z SUN... LINGERING MOIST
E WINDS/SHALLOW COLD AIR WL RESULT IN LINGERING LO CLDS/FOG/SOME
-FZDZ...ESPECIALLY AT CMX AND SAW WHERE THE FLOW WL UPSLOPE.
&&

.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 516 AM EDT SAT APR 12 2014

EAST WINDS WILL INCREASE TO 25 KNOTS OVER THE WRN HALF OF THE LAKE
TODAY AS THE PRES GRADIENT TIGHTENS BTWN HIGH PRES BUILDING FROM NRN
ONTARIO INTO QUEBEC AND A LOW INTO IA. WINDS ARE ALSO EXPECTED TO
INCREASE TO 30 KNOTS MONDAY OVER CNTRL AND ERN LAKE SUPERIOR BETWEEN
HIGH RPESSURE OVER THE PLAINS AND A LOW PRES SYSTE OVER THE ERN
GREAT LAKES.
&&

.HYDROLOGY...
ISSUED AT 417 AM EDT SAT APR 12 2014

FORTUNATELY...LIMITED RAINFALL AND TEMPERATURES NEAR OR SLIGHTLY
ABOVE NORMAL HAS KEPT THE SNOWMELT SIMILAR TO NORMAL SPRING
CONDITIONS. WOULD EXPECT A SLOW STEADY RISE IN RIVER LEVELS
TODAY...WITHOUT ANY LARGER RIVERS RISING ABOVE BANKFULL AT THIS TIME.
THE PROBLEM AREAS SO FAR HAVE BEEN SMALL CREEKS AND STREAMS IN DELTA
COUNTY WHERE HAVE BEEN NEAR OR OUT OF THEIR BANKS OVER THE PAST
COUPLE OF DAYS. HOWEVER...NO SIGNIFICANT IMPACTS WERE NOTED. THERE
HAS SEEN EVIDENCE OF MINOR ICE JAMES ON SOME HYDROGRAPHS OVER THE
LAST DAY OR SO...MOST NOTABLY ON THE ONTONAGON RIVER NEAR ROCKLAND
(RKLM4) AND THE FORD RIVER NEAR HYDE (FRDM4). THE RKLM4 ICE JAM SEEMS
TO HAVE MOVED DOWNSTREAM OR BROKEN UP...BUT DO NOT KNOW ABOUT THE
STATE OF THE RIVER DOWNSTREAM GIVEN A LACK OF REPORTS/RIVER ACCESS.
THE FRDM4 ICE JAM LOOKS TO HAVE RELAXED FRIDAY EVENING. CURRENTLY
HAVE ISSUED A STATEMENT FOR THAT RIVER TO WARN OF FLUCTUATING RIVER
LEVELS AND ICE IS LIKELY STILL IN THE SYSTEM. AM UNSURE OF
IMPACTS/EXTENT OF THIS ICE JAM AS RIVER BANKS/STRUCTURES ARE FAIRLY
HIGH ABOVE THE RIVER PER DISCUSSION WITH LOCAL OFFICIALS. THERE WERE
ALSO REPORTS OF MINOR ICE JAMS ON OTHER AREA CREEKS/STREAMS THAT ARE
NOT GAUGED...BUT NO IMPACTS WERE NOTED. THIS ICE BREAK UP DOES LEAD
TO SOME CONCERN FOR ICE JAMS ON OTHER RIVERS ACROSS THE
CWA...ESPECIALLY FOR RIVERS THAT EMPTY INTO THE MAINLY FROZEN GREAT
LAKES.

A LOW PRESSURE TROUGH MOVING THROUGH THE UPPER GREAT LAKES REGION
TODAY WILL LEAD TO PERIODS OF RAIN AND SNOW /MELTING AS IT FALLS/
THROUGH SATURDAY EVENING. THE CURRENT FORECAST CALLS FOR AMOUNTS TO
BE IN THE 0.30-0.50 INCH RANGE...BUT WITH COOLER TEMPERATURES
ARRIVING WITH THIS RAIN...THE IMPACT ON THE RIVERS SHOULD BE
LIMITED. EXPECT COLDER AIR TO SURGE IN SUNDAY NIGHT THROUGH THE
FIRST HALF OF THE WORK WEEK. THIS WILL SIGNIFICANTLY REDUCE OR EVEN
END THE SNOW MELT...AS HIGHS WILL ONLY BE IN THE 30S AND LOWS WILL
BE WELL BELOW FREEZING. SINCE 4-9 INCHES OF SNOW WATER EQUIVALENT
STILL REMAINS OVER PARTS OF WESTERN AND CENTRAL UPPER
MICHIGAN...THERE IS STILL PLENTY OF WATER AVAILABLE FOR THE SECOND
PERIOD OF SNOW MELT OVER THE NEXT COUPLE OF WEEKS.
&&

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

$$

SHORT TERM...JLB
LONG TERM...KF
AVIATION...KC
MARINE...JLB
HYDROLOGY...KF






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