Area Forecast Discussion
Issued by NWS Marquette, MI

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000
FXUS63 KMQT 190418
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
1218 AM EDT SAT APR 19 2014

.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 428 PM EDT FRI APR 18 2014

A SHORTWAVE TROUGH IS CURRENTLY OVER THE NRN ROCKIES...WITH A
STRENGTHENING SFC LOW OVER MT/WY. ADDITIONALLY...THERE IS A WEAK
SHORTWAVE TROUGH AND 1031MB SFC HIGH OVER THE CWA. THE ROCKIES
SHORTWAVE WILL MOVE TO ECENTRAL MANITOBA/ECENTRAL ONTARIO BY 00Z
SUN.

CLEARING SKIES BEHIND THE WEAK SHORTWAVE OVERHEAD MAY ALLOW SOME FOG
TO DEVELOP OVER PORTIONS OF THE ERN HALF OF THE CWA. HIGH CLOUDS
MOVING INTO THE WRN CWA EARLIER TONIGHT WILL LIMIT FOG POTENTIAL
THERE.

PRECIP WILL MOVE INTO THE WRN CWA SAT MORNING AS STRONG FORCING FROM
ISENTROPIC ASCENT/WAA AND LOW-MID LEVEL MOISTURE ADVECTION. THE
MOISTURE TRANSPORT WILL BE NEEDED AS THE AIRMASS ABOVE THE NEAR SFC
INVERSION WILL BE QUITE DRY. THIS DRYNESS SHOULD HOLD THE PRECIP OFF
UNTIL AFTER 12Z OVER UPPER MI...WHICH ALLOWS FOR WARMER AIR TO MOVE
IN...MAKING RAIN THE DOMINANT PTYPE ON SAT. DO HAVE SOME SNOW EARLY
OVER THE KEWEENAW...BUT WOULD NOT BE SURPRISED TO NOT SEE ANY PRECIP
UNTIL LOW-MID LEVEL TEMPS WARM ENOUGH FOR ALL RAIN. ANOTHER AREA OF
MIXED PRECIP IS OVER FAR WRN UPPER MI WHERE THE RAIN WILL START
BEFORE SFC TEMPS ARE ABOVE FREEZING...SOME SOME VERY MINOR FREEZING
RAIN ACCUMULATIONS ARE POSSIBLE THERE EARLY. AS FAR AS PRECIP
AMOUNTS...HAVE NO QPF SCENTRAL AND E...WITH UP TO 0.40 INCHES OVER
THE KEWEENAW ON SAT. THE PRECIP MOVES SE ACROSS THE REST OF THE CWA
SAT NIGHT INTO SUN...SEE THE LONG TERM DISCUSSION FOR THE DETAILS OF
THAT TIME FRAME.

.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 428 PM EDT FRI APR 18 2014

...MAIN CONCERN OVER THE LONG TERM PERIOD IS MODERATE RAINFALL AND
ABOVE AVERAGE TEMPERATURES SATURDAY THROUGH SUNDAY AFTERNOON ACROSS
UPPER MICHIGAN...

MODELS ARE CONSISTENT IN BRINGING A LOW PRESSURE SYSTEM ACROSS UPPER
MICHIGAN STARTING SATURDAY AFTERNOON AND CONTINUING THROUGH MAINLY
SUNDAY MORNING. THIS LOW WILL BRING TOTAL QPF AROUND 0.25-0.5 INCHES
OF RAIN TO WEST AND CENTRAL UPPER MI...AND 0.5 TO 0.7 INCHES OF RAIN
TO EASTERN UPPER MI THROUGH SUNDAY AFTERNOON. HIGH TEMPERATURES
DURING THIS PERIOD WILL RISE INTO THE 40S AND 50S...WITH AREAS
FURTHER SOUTH SEEING NEAR 60. THIS WILL LEAD TO HYDROLOGY
CONCERNS...WHICH IS DISCUSSED IN THE HYDROLOGY SECTION BELOW.

PLENTY OF UPPER LEVEL SUPPORT EXISTS FOR PRECIPITATION. THE RIGHT
ENTRANCE REGION OF A 300MB JET IS POSITIONED FAVORABLY OVER UPPER
MI...AND A 500MB TROUGH BRINGS MODEST 850-500MB QVECTOR CONVERGENCE
FROM WEST TO EAST THROUGHOUT THE NIGHT. MOISTURE IS ADEQUATE AS
WELL. AN AREA OF WAA/ISENTROPIC ASCENT AHEAD OF THE LOW INFILTRATES
THE AREA...BRINGING PWATS UP TO NEAR 250 PERCENT OF NORMAL. BY THE
START OF THE LONG TERM PERIOD/SATURDAY NIGHT/ BEST MOISTURE IS
SPREAD ACROSS THE WESTERN AND CENTRAL CWA.

MODELS HAVE ALSO BEEN CONSISTENT IN HANGING UP THE FRONT ACROSS
NORTHERN LOWER MI SUNDAY AFTERNOON....BUT THEY DIFFER IN RESPECT TO
HOW FAR NORTH THE FRONT WILL STALL. THE GEM/ECMWF KEEP THE EASTERN
AND FAR SOUTHERN CWA UNDER CLOUDS AND PRECIPITATION...AND THE GFS/NAM
MOVE THE PRECIPITATION OUT OF ALL BUT THE VERY FAR EASTERN PORTIONS
OF UPPER MI. DIFFERENCES ARE LARGELY WITH THE STRENGTH OF HIGH
PRESSURE/INCOMING DRY AIR BEHIND THE LOW...WHICH FORCES THE
PRECIPITATION FURTHER SOUTH. FOR NOW...KEPT POPS/QPF CONSERVATIVE
SUNDAY AFTERNOON ACROSS THE SOUTH AND EAST...AND STARTED A CLOUD
DIMINISHING TREND IN THE WEST/NORTH CENTRAL.

WITH WARMER AIR ADVECTING INTO THE REGION SATURDAY AND
SUNDAY...850MB TEMPS RISE UP TO 4 TO 8C...LEADING TO HIGHS ACROSS
THE CWA IN THE 40S AND 50S SATURDAY...AND THE 50S AND LOW 60S
SUNDAY. THE WARMEST TEMPERATURES WILL BE WEST AND NORTH CENTRAL
WHERE CLOUD COVER CLEARS OUT.

MODELS ALSO STRUGGLED WITH THE NEXT INCOMING SYSTEM...MOVING ACROSS
THE PLAINS STATES SUNDAY EVENING INTO MONDAY. WITH THE STATIONARY
FRONT STILL STUCK IN PLACE JUST SOUTH OF THE AREA...WARM AIR AND
ADDITIONAL MOISTURE ADVECTING INTO THE REGION FROM THE APPROACHING
LOW COULD PUSH THE PRECIPITATION NORTHWARD INTO THE CWA FOR MONDAY.
THE GEM/ECMWF ARE PRETTY CONSISTENT IN THIS...HOWEVER THE NAM/GFS
KEEP THE FRONT SOUTH. KEPT PRECIPITATION SOUTH AND EAST FOR
NOW...AND INCREASED FROM SLIGHT CHANCE TO CHANCE BY MONDAY
AFTERNOON. THE UPPER LEVEL TROUGH/SFC TROUGH SWING THROUGH ON
TUESDAY...BUT AGAIN MODELS ARE HAVING DIFFICULTIES WITH THIS. KEPT
CONSENSUS SLIGHT CHANCE POPS AS A RESULT.

HIGH PRESSURE MOVES IN ON WEDNESDAY...BRINGING A BRIEF BREAK TO THE
PRECIPITATION...THOUGH LIGHT NORTHERLY FLOW WILL KEEP TEMPERATURES
RELATIVELY COOL...WITH HIGHS IN THE 40S AND LOW 50S. CLOUDS AHEAD OF
THE NEXT APPROACHING SYSTEM WILL MOVE IN FROM WEST TO EAST
THROUGHOUT THE DAY.

THURSDAY INTO FRIDAY MODELS DIVERGE WITH THEIR SOLUTIONS AND
HANDLING OF THE LOW PRESSURE TROUGH DRIFTING ACROSS THE PLAINS. THE
GFS GENERATES EXCESSIVE QPF OVER UPPER MI ASSOCIATED WITH AN
INVERTED TROUGH ASSOCIATED WITH THIS LOW...BUT THE ECWMF DOES NOT.
THE GFS SEEMS TO WRAP UP THE SYSTEM MORE THAN THE ECMWF...AND DIGS
THE TROUGH DEEPER. THE GFS ALSO BRINGS 850MB TEMPS OF 10C BY 00Z
SATURDAY...WHEREAS THE ECMWF 850MB TEMPS DO NOT EVEN REACH ABOVE 0C.
FOR NOW WILL REMAIN WITH CONSENSUS GRIDS DUE TO THESE SIGNIFICANT
DIFFERENCES.
&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1215 AM EDT SAT APR 19 2014

VFR CONDITIONS ARE EXPECTED AT KIWD/KCMX THRU THE NIGHT WITH ONLY
HIGH AND MID CLOUDS INCREASING OVER DRY LOW-LEVEL AIR MASS. AT
KSAW...RADIATIONAL COOLING MAY BE SUFFICIENT BEFORE HIGHER CLOUDS
ARRIVE TO RESULT IN FOG/MVFR VIS. ALTHOUGH MOISTURE ALOFT CONTINUES
TO INCREASE TODAY...LINGERING DRY LOW-LEVELS MAKES PCPN FCST LESS
CERTAIN. BEST CHC OF DRY LOW-LEVELS GIVING WAY IS AT KCMX. SOME SHRA
ARE EXPECTED THERE IN THE AFTN. SPRINKLES MAY AFFECT KIWD. BETTER
CHC OF SHRA WILL OCCUR LATE AFTN AT KIWD/KCMX AND IN THE EVENING AT
KSAW. VFR CONDITIONS SHOULD GENERALLY CONTINUE...THOUGH KCMX MAY
FALL TO MVFR WITH SOMEWHAT HEAVIER SHRA EXPECTED THERE.
&&

.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 428 PM EDT FRI APR 18 2014

WINDS GENERALLY BELOW 20 KTS THROUGH THE ENTIRE FORECAST PERIOD. ONLY
EXCEPTION WILL BE SATURDAY AND SATURDAY NIGHT AS EAST TO SOUTHEAST
WINDS INCREASE TO 20 TO 30 KTS ON FLANK OF LOW PRESSURE MOVING FROM
NORTHERN PLAINS INTO NORTHERN ONTARIO.
&&

.HYDROLOGY...
ISSUED AT 428 PM EDT FRI APR 18 2014

AS MENTIONED IN PREVIOUS FORECAST DISCUSSIONS...THE RECENT HEAVY
SNOWFALL ACROSS WESTERN UPPER MI HAS REPLENISHED SOME OF THE WATER
CONTENT THAT WAS LOST DURING THE WARMER CONDITIONS OVER THE PAST TWO
WEEKS. THE WESTERN HIGH TERRAIN NOW HAS 6 TO 8 INCHES OF WATER
EQUIVALENT...WITH LOCALIZED 10 INCH AMOUNTS. SINCE TEMPERATURES ARE
EXPECTED TO BE AT OR SLIGHTLY ABOVE AVERAGE ACROSS UPPER MI THIS
WEEKEND INTO MON /THE UPPER 50S AND LOW 60S AWAY FROM LOCAL LAKE
COOLING ON SUN AND MON/...A GOOD DEAL OF MELTING SHOULD OCCUR.
EXCEPT FOR SAT NIGHT...LOW TEMPERATURES WILL FALL TO AT LEAST NEAR
FREEZING...LIMITING CONCERNS OF RAPID MELTING. COOLER AIR WILL
RETURN MON NIGHT INTO THURSDAY...SOMEWHAT MODERATING THE MELT DOWN.
HIGHS ARE STILL EXPECTED TO RANGE FROM THE 40S TO THE LOW 50S.

AS FOR PRECIPITATION...AN ADDITIONAL 0.3 TO 0.75 INCHES OF LIQUID IN
THE FORM OF MOSTLY RAIN IS EXPECTED SAT AFTERNOON INTO EARLY SUNDAY
AFTERNOON. WITH THE ADDITIONAL LIQUID ADDED TO THE SNOWPACK FROM THE
RECENT SNOW STORM...WARM TEMPERATURES...AND LIGHT TO MODERATE
RAINFALL...A PROLONGED PERIOD OF HIGHER RIVER FLOWS ARE EXPECTED.

THOUGH WIDESPREAD FLOODING IS NOT A CONCERN AT THIS TIME...REMAINING
ICE ON THE RIVERS COULD LEAD TO POTENTIAL ICE JAMS ONCE THE WARMER
AIR ARRIVES SAT THRU MON. THOSE LIVING AROUND RIVERS...CREEKS...AND
STREAMS SHOULD MONITOR BOTH RIVER LEVELS AND ICE CONDITIONS. ICE
JAMS CAN FORM AND BREAK QUICKLY...RESULTING IN RAPIDLY FLUCTUATING
RIVER LEVELS.
&&

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

$$

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







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