Area Forecast Discussion
Issued by NWS Marquette, MI

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000
FXUS63 KMQT 120817
AFDMQT

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

.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 448 PM EDT FRI APR 11 2014

A SHORTWAVE OVER THE CENTRAL CWA IS PRODUCING ISOLATED TO SCATTERED
RAIN SHOWERS. COVERAGE/INTENSITY WOULD BE GREATER IF NOT FOR THE LOW
LEVELS BEING DRY WITH AN INVERTED V LOOK BELOW 800MB WHEN LOOKING AT
MODEL SOUNDINGS. ALSO...A SFC TROUGH IS MOVING INTO THE WRN
CWA...WHICH IS JUST PRODUCING SOME LIGHT ISOLATED SHOWERS THAT
SHOULD DIMINISH AS THEY MOVE E.

GREATEST CONCERN IN THE SHORT TERM IS PTYPE/AMOUNTS SAT. MODELS ARE
IN GOOD AGREEMENT SHOWING QPF MOVING IN MAINLY AFTER 12Z SAT. PRECIP
WILL BE THE RESULT OF A SHORTWAVE MOVING FROM THE NRN PLAINS INTO
THE UPPER GREAT LAKES...WITH AN ASSOCIATED SFC TROUGH MOVING FROM MN
INTO WI. THE SHORTWAVE ENERGY WILL COMBINE WITH ISENTROPIC ASCENT ON
THE 285-305K SURFACES...850-700MB FGEN...700-500MB LAPSE RATES OF
6.5-7.5C/KM AND THE RIGHT ENTRANCE REGION OF THE UPPER JET TO
PRODUCE A DECENT BAND OF PRECIP MOVING ACROSS THE CWA. HOWEVER...THE
PRECIP WILL INITIALLY HAVE TO SATURATE DRY LOW LEVELS...WHICH WILL
LIMIT PRECIP AMOUNTS SOMEWHAT AND MORE SIGNIFICANTLY COOL THE LOW
LEVEL AIRMASS TO THE WET BULB TEMPS. MODELS HAVE TRENDED COLDER AND ARE
IN GOOD AGREEMENT WITH LOW-MID ATMOSPHERE AIRMASS...WHICH NOW
FAVORS SNOW OVER NRN UPPER MI UNTIL LATE IN THE DAY WHEN WARMER AIR
SURGES NORTHWARD INCREASING CHANCES OF RAIN...AND MOSTLY RAIN IN THE
SRN CWA. PTYPE IS PRETTY TRICKY AS THE THERMAL PROFILE IS CLOSE TO
THE 0C LINE...AND A WARM NOSE MOVES IN FROM THE S IN THE
AFTERNOON...ALONG WITH A DRYING OF THE DGZ...BUT DID NOT GET
EXTREMELY SPECIFIC AT THIS TIME AS IMPACTS FROM NON SNOW/RAIN PTYPES
ARE MINIMAL. EVEN WITH 12Z SAT TO 00Z SUN QPF AMOUNTS OF 0.30-0.45 INCHES
IN THE GRIDS /WHICH IS A CONSENSUS OF MODEL GUIDANCE...BUT EXTREMES
ARE FAIRLY CLOSE TO THE MEAN/...SNOWFALL AMOUNTS ARE LIMITED BY SFC
TEMPS IN THE MID-UPPER 30S OVER SNOW FAVORED AREAS...SO SNOW WILL
MELT AS IT FALLS IN MANY LOCATIONS. HAVE THE GREATEST SNOW
ACCUMULATIONS OVER THE KEWEENAW PENINSULA OF 1-2 INCHES...HIGHEST
OVER THE HIGHER TERRAIN. THINK THE SNOWFALL AMOUNTS COULD BE A BIT
LOW IF THE SNOW COMES IN A SHORTER/HEAVIER BURST THAT WOULD
ACCUMULATE FASTER THAN IT MELTS.

.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 337 PM EDT FRI APR 11 2014

NAM SHOWS A 500 MB RIDGE OFF THE WEST COAST 00Z SUN WITH A TROUGH IN
THE DESERT SW AND A TROUGH OVER THE NORTHERN ROCKIES AND A SHORTWAVE
OVER LAKE WINNIPEG. THE TROUGH IN THE NORTHERN ROCKIES COMBINES WITH
A SHORTWAVE TROUGH IN CENTRAL CANADA TO CARVE OUT A DEEP TROUGH THAT
DEVELOPS OVER THE NORTHERN PLAINS 00Z MON AND THIS TROUGH MOVES
SLOWLY TO THE EAST ON MONDAY.

DID NOT MAKE TOO MANY CHANGES TO THE GOING FORECAST. HAVE LIKELY
POPS IN THE EAST FOR SAT EVENING WITH EXITING SYSTEM. NEXT SYSTEM
ARRIVES FOR SUN AFTERNOON INTO MONDAY. COLDER AIR ALSO ARRIVES AND
SHOULD SWITCH PCPN OVER TO ALL SNOW SUNDAY NIGHT INTO MONDAY.
HIGHEST POPS WITH THIS SYSTEM WILL BE OVER THE SOUTH AND EASTERN CWA
WHERE A STALLED OUT FRONT WILL BE WELL SOUTHEAST OF THE AREA THEN.
THIS SYSTEM RIGHT NOW LOOKS TO TRACK A BIT FURTHER EAST...BUT IF IT
DECIDES TO GO FURTHER NORTH OR WEST...THEN POPS AND QPF AMOUNTS WILL
HAVE TO BE RAISED.

IN THE EXTENDED...GFS AND THE ECMWF SHOW A DEEP 500 MB TROUGH ACROSS
THE CENTRAL U.S. 12Z TUE WITH VERY COLD AIR ACROSS THE AREA. SFC
HIGH PRESSURE MOVES INTO THE AREA 12Z WED WITH THE TROUGH AXIS EAST
OF THE AREA THEN. ANOTHER UPPER TROUGH MOVES INTO THE AREA 12Z THU.
THIS TROUGH...THE MODELS HAVE TROUBLE WITH FOR FRI AS THE GFS TAKES
IT THROUGH THE AREA AND HAS SOME ENERGY MOVING INTO THE NORTHERN AND
CENTRAL PLAINS. THE ECMWF DOES NOT MOVE THE TROUGH THROUGH AND HANGS
IT UP TO THE WEST. THIS WILL MEAN TEMPERATURES WILL BE BELOW NORMAL
THIS FORECAST PERIOD. THIS WILL ALSO MEAN THAT MOST OF THE PCPN WILL
BE SNOW IF ANY FALLS THIS PERIOD AND ONLY DRY PERIODS LOOK TO BE TUE
NIGHT AND WED. OTHERWISE...SMALL CHANCES FOR POPS.
&&

.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 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 337 PM EDT FRI APR 11 2014

NO GALES SEEN ANYTIME SOON. STRONGEST WINDS LOOK TO BE MONDAY WITH
NORTH WINDS GUSTING TO 25 KNOTS. STRONG PRESSURE SYSTEMS STAY AWAY
FROM THE AREA.
&&

.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...TITUS
LONG TERM...07
AVIATION...KC
MARINE...07
HYDROLOGY...KF






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