Area Forecast Discussion
Issued by NWS Marquette, MI

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000
FXUS63 KMQT 211859
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
259 PM EDT MON JUL 21 2014

.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 258 PM EDT MON JUL 21 2014

UPPER AIR PATTERN CONSISTS OF A 500 MB RODGE ACROSS THE SOUTHERN
PLAINS WITH A CLOSED 500 MB LOW ACROSS NORTHERN MANITOBA. THE
WESTERLIES ARE BETWEEN THESE TWO SYSTEMS ACROSS THE NORTH CENTRAL
U.S. WITH THE UPPER GREAT LAKES ON THE PERIPHERY OF THE RIDGE AND IN
THE RING OF FIRE CONVECTION ZONE. ANY LITTLE SHORTWAVE MOVING
THROUGH THE WESTERLIES COULD SPARK CONVECTION WHICH MAKES THIS
FORECAST MORE DIFFICULT AND CONFIDENCE IS LOWER THAN IT NORMALLY
WOULD BE. THE ONE SHORTWAVE OF INTEREST IS IN SOUTHERN MT AND
NORTHERN WY THIS MORNING AND THIS HEADS EAST INTO NORTHERN MN LATE
TONIGHT AND ACROSS THE AREA ON TUE. NAM...GFS AND 12Z CANADIAN
APPEAR TO BE SUFFERING FROM CONVECTIVE FEEDBACK ISSUES AND THEIR
SOLUTION ARE SUSPECT.

USED THE 00Z ECMWF AND 00Z CANADIAN MODELS FOR THIS FORECAST WHICH
WAS FAIRLY SIMILAR TO THE GOING FORECAST. 12Z GFS DOES HAVE A HINT
OF THE HEAVIEST QPF AND CONVECTION STAYING OFF TO THE NORTH OF THE
AREA WHICH THERE COULD BE SOMETHING TO THIS. FURTHER SOUTH COULD BE
CAPPED. WILL GO MORE WITH THIS SCENARIO AND HAVE A LINE OF
CONVECTION MOVE THROUGH THE AREA STARTING LATE TONIGHT AND GO WITH
HIGH POPS AS THIS MOVES THROUGH LATE TONIGHT THROUGH TUE. QPF
AMOUNTS LOOK TO BE 0.25 INCH TO 1.4 INCHES WITH THE LIGHTEST AMOUNTS
IN THE SOUTH AND EAST AND THE HEAVIEST OVER THE WEST AND NORTH.
AGREE WITH SPC THINKING WITH SLIGHT RISK OVER THE WESTERN CWA FOR
LATE TONIGHT WITH POSSIBILITY OF SOME FORWARD PROPAGATING MCS MOVING
THROUGH OR NEARBY. OVERALL...DID NOT MAKE TOO MANY CHANGES TO THE
GOING FORECAST AS MOST OF THE MODELS WERE CONTAMINATED WITH
CONVECTION WHICH WOULD ALSO MESS UP THE SFC WINDS ON TUE. USED THE
CANADIAN AND ECMWF WINDS FOR THE AFTERNOON AS THE CONTAMINATED
MODELS WERE ALL GOING GALES WHICH SEEMED WAY OVERDONE...PLUS COLD
MARINE LAYER WILL BE THERE TO CUT THE WINDS OFF BEFORE THEY HIT THE
WATER SURFACE.

.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 748 AM EDT MON JUL 21 2014

MAIN FOCUS IS ON TUESDAY AS MCS ACTIVITY SHOULD BE MOVING ACROSS THE
CWA. DEVELOPMENT OF A FORWARD PROPAGATING MCS OVER ND MON EVENING
LOOKS LIKELY TO OCCUR...WHICH WOULD BRING THE REMNANTS OF THE MCS
INTO THE CWA MON NIGHT /SEE SHORT TERM DISCUSSION/. THE REMNANTS OF
THE MCS SHOULD THEN MOVE ACROSS THE CWA DURING THE DAY TUE...WITH
THE CURRENT FAVORED TRACK OF THE BEST PRECIP CHANCES OVER LAKE
SUPERIOR/NRN UPPER MI. SO MUCH OF THE PRECIP AND STORM INTENSITY
DURING THE DAY TUE WILL BE DEPENDENT ON MANY OTHER FACTORS...SO
CONFIDENCE IN EXACT DETAILS IS LIMITED. HOWEVER...THINK THAT THE
THREAT FOR SEVERE WEATHER IS LOW GIVEN THAT MORNING INSTABILITY
SHOULD BE AROUND 1000J/KG /HIGHEST OVER THE W NEAR IWD/. AS THE
CONVECTION MOVES E INTO THE AFTERNOON IT WILL ENCOUNTER MORE STABLE
CONDITIONS...SO SEVERE WEATHER IS EVEN LESS LIKELY. A WAKE LOW IS
QUITE POSSIBLE BEHIND THE CONVECTION...WHICH WOULD LEAD TO GUSTY
WINDS...ESPECIALLY OVER LAKE SUPERIOR. WOULD THINK THAT THE THREAT
FOR SIGNIFICANT SEICHE ACTIVITY ON LAKE SUPERIOR IS PRETTY HIGH. MAY
SEE ANOTHER WAVE OF CONVECTION TRYING TO MOVE THROUGH BEHIND THE
INITIAL CONVECTION...BUT THINK THAT THERE WILL NOT BE AS MUCH
INSTABILITY TO WORK WITH DUE TO THE EARLIER CONVECTION.

PRECIP SHOULD BE SE OF THE CWA BY 06Z WED...AND DRY AND COOLER
WEATHER IS EXPECTED THROUGH FRI AS A SFC HIGH MOVES THROUGH THE
REGION. PRECIP CHANCES WILL RETURN OVER THE WEEKEND AS A MORE
UNSETTLED PATTERN SETTLES OVER THE REGION.
&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 110 PM EDT MON JUL 21 2014

VFR CONDITIONS WILL PREVAIL AT KIWD/KCMX/KSAW INTO THE OVERNIGHT
HOURS. SHRA/TSTMS DEVELOPING OVER THE NRN PLAINS THIS AFTN/EVENING
WILL MOVE E. THE STORMS SHOULD HOLD TOGETHER AND REACH WRN UPPER MI
LATE TONIGHT...AFFECTING KIWD/KCMX AROUND 09Z OR LATER. MVFR
CONDITIONS SHOULD ACCOMPANY THE PCPN WITH POTENTIAL FOR IFR.
CONFIDENCE WITH STORMS AND WIND DIRECTIONS IS LOW AFTER 09Z AT ALL
SITES AS THE STORMS WILL MANUFACTURE THEIR OWN WEATHER AND MODELS
WILL NOT BE ABLE TO HANDLE THIS.
&&

.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 258 PM EDT MON JUL 21 2014

SOUTHERLY WINDS WILL CONTINUE OVER MOST OF LAKE SUPERIOR TONIGHT.
ON TUE...A LOW PRESSURE SYSTEM WILL PASS ACROSS THE UPPER
LAKES...BRINGING A WIND SHIFT TO THE N. AGAIN...THE STRONGER WINDS
OF 15-25KT WILL LIKELY OCCUR OVER ERN LAKE SUPERIOR. IN ADDITION...
DEPENDING ON STRENGTH/COVERAGE AND EVOLUTION OF TSTMS MOVING ACROSS
LAKE SUPERIOR TONIGHT/TUE AHEAD OF LOW...THERE MAY BE A PERIOD OF
STRONG WINDS ACROSS MUCH OF THE LAKE FOR A TIME LATE TONIGHT AND
TUE. HIGH PRES WILL SETTLE INTO THE GREAT LAKES LATE WED THRU
SAT...PROVIDING A PERIOD OF LIGHT WINDS.

ON A FINAL NOTE...FOG MAY EXPAND ACROSS LAKE SUPERIOR THRU
TUE...ESPECIALLY ONCE PCPN OCCURS.
&&

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

$$

SHORT TERM...07
LONG TERM...TITUS
AVIATION...07
MARINE...07





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