000
FXUS63 KMQT 210901
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
501 AM EDT TUE MAY 21 2013

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 500 AM EDT TUE MAY 21 2013

UPPER AIR PATTERN CONSISTS OF A CLOSED 500 MB LOW OVER SD WITH AN
ASSOCIATED TROUGH OVER THE NORTHERN AND CENTRAL PLAINS...A 500 MB
RIDGE OVER THE LOWER GREAT LAKES AND ACROSS THE NORTHERN ROCKIES.
THE 500 MB LOW MOVES SLOWLY SE THIS FORECAST PERIOD WITH THE TROUGH
MOVING INTO THE UPPER GREAT LAKES.

COMPLICATED FORECAST AGAIN TODAY COMPLICATED FURTHER BY A
SIGNIFICANT DATA OUTAGE THAT AFFECTED OBS AND COMPUTER PERFORMANCE.
ANYWAY...TRYING TO TIME OUT SHORTWAVES MOVING THROUGH AND KICKING
OFF CONVECTION WILL CONTINUE TO BE TOUGH. THERE WILL BE A WAVE OF
CONVECTION GOING THROUGH EARLY THIS MORNING...THEN MAY SEE A BRIEF
BREAK BEFORE MORE REDEVELOPMENT AS THE MORNING GOES ON. THINK THE
REDEVELOPMENT WILL BE SCATTERED POPS THIS AFTERNOON. WILL START OFF
WITH CATEGORICAL TO LIKELY POPS EARLY THIS MORNING THOUGH. AS FOR
TEMPERATURES...AGAIN ANY SUNSHINE THAT OCCURS HAS THE POTENTIAL TO
LEAD TO A BIG FORECAST BUST. THINKING IS THERE COULD BE A LITTLE
SUNSHINE ALONG THE WISCONSIN BORDER...BUT SHOULD NOT LAST THAT LONG
TO AFFECT TEMPERATURES THAT MUCH. DID KEEP LOWER 70S FOR HIGHS TODAY
IN THAT AREA WITH COOLER TEMPERATURES ELSEWHERE...ESPECIALLY NEAR
THE GREAT LAKES SHORELINES. CHANCE POPS FOR TONIGHT LOOK TO CONTINUE
AS THE SYSTEM WEAKENS FURTHER AND STARTS TO DROP A BIT SOUTHWARD
WITH TIME. DID NOT MAKE TOO MANY CHANGES TO THE GOING FORECAST FOR
TEMPERATURES EXCEPT TO LOWER THEM A BIT NEAR THE LAKESHORE AREAS AS
WATER TEMPERATURES ARE STILL PRETTY COLD. AS FOR FOG...KEPT THE
ADVISORY GOING IN THE KEWEENAW THIS MORNING AS CONDITIONS DO NOT
CHANGE MUCH WITH UPSLOPE MOIST FLOW OFF OF LAKE SUPERIOR. RAIN THAT
FALLS INTO LAKE SUPERIOR WILL CONTINUE TO CAUSE UPSLOPE FOG THERE
FOR AT LEAST THIS MORNING.

.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 409 PM EDT MON MAY 20 2013

THE FOCUS OF THE LONG TERM FORECAST THIS WEEK WILL BE THE PASSING OF
A LOW PRESSURE SYSTEM ACROSS THE GREAT LAKES REGION. CLOSED 500MB
LOW OVER THE NORTHERN PLAINS THIS AFTERNOON WILL MAKE ITS WAY JUST
SOUTH OF UPPER MICHIGAN ON WEDNESDAY...GRADUALLY FILLING AS IT
REACHES THE EASTERN SEABOARD BY FRIDAY AFTERNOON. THIS LOW EXTENDS
FROM A TROUGH ASSOCIATED WITH STRONGER LOW PRESSURE SITUATED OVER
NORTHERN QUEBEC. AT THE 300MB LEVEL LEFT EXIT REGION DIVERGENCE HAS
HELPED WITH THE DEVELOPMENT OF THE LOW PRESSURE SYSTEM OVER THE
PLAINS. THIS JET WILL SHIFT NORTHWARD AND BY WEDNESDAY UPPER
MICHIGAN WILL BE SLIGHTLY NORTH OF THE BEST UPPER LEVEL SUPPORT...IN
THE RIGHT ENTRANCE REGION. 850-500MB QVECTOR CONVERGENCE SHOWS BEST
LIFT GENERALLY ALONG SOUTHWESTERN-SOUTHERN UPPER MI/LOWER
MI/WISCONSIN ACCORDINGLY. MEANWHILE...A WEAK SURFACE LOW DEVELOPING
IN THE PLAINS MOVES NORTHWARD ALONG THE TROUGH...PASSING THROUGH
LOWER MI AND THE LOWER GREAT LAKES WEDNESDAY AFTERNOON INTO
WEDNESDAY NIGHT. MODEL SOUNDINGS SHOW ABUNDANT MOISTURE REMAINS
THROUGH ALL OF WEDNESDAY FOR CENTRAL/EASTERN UPPER MI BEFORE THE
VERY DRY AIRMASS/HIGH PRESSURE ARRIVES WEDNESDAY NIGHT/THURSDAY.
PWATS DURING THIS TIME STILL REMAIN AS HIGH AS 150 PERCENT OF
NORMAL. HAVE A DIMINISHING TREND FOR POPS FROM WEDNESDAY AFTERNOON
ONWARD AS DRY AIR INFILTRATES THE AREA AND THE SFC LOW EXITS THE
REGION. ADDITIONALLY...WITH ABUNDANT MOISTURE IN PLACE EXPECTING FOG
ACROSS LAKE SUPERIOR AND LAKE MICHIGAN FOR TUESDAY NIGHT/EARLY
WEDNESDAY AFTERNOON. ONCE THE DRIER AIR MOVES IN THE FOG WILL
DISSIPATE.

UPPER LEVEL HIGH OVER THE CANADIAN PRAIRIE WILL SINK SOUTHWARD AND
MERGE WITH THE BUILDING RIDGE OVER THE CENTRAL UNITED STATES ON
THURSDAY MORNING...BRINGING AN END TO PRECIPITATION FOR UPPER MI.
WITH DRY AIR SCOURING OUT THE CLOUDS...NORTHERLY WINDS...AND 850MB
TEMPS AROUND 2-4C...THURSDAY AFTERNOON LOOKS TO BE MOSTLY SUNNY WITH
TEMPS IN THE MID-UPPER 50S AND MAYBE EVEN LOW 60S....BELOW NORMAL BY
LATE MAY STANDARDS. MIXED LAYER DEWPOINTS BRING DEWPOINTS INTO THE
UPPER 20S/30S WHICH BRINGS MINIMUM RH FIELDS TO 30-40 PERCENT FOR
MID AFTERNOON ON THURSDAY.

A SHORTWAVE ROTATING AROUND THE 500MB LOW IN QUEBEC WILL PASS
OVERHEAD FRIDAY AFTERNOON BUT WITH DRY AIR FIRMLY IN PLACE NOTHING
WILL COME OF IT BEYOND SOME SCATTERED CLOUDS. AFTER FRIDAY THE UPPER
LEVEL RIDGE WILL SPRAWL ACROSS MUCH OF THE CENTRAL AND EASTERN
UNITED STATES. THIS WILL KEEP A DRIER AIRMASS IN PLACE AND KEEP
CONDITIONS QUIET THROUGH SATURDAY AFTERNOON. A LOW PRESSURE
TROUGH/SHORTWAVE WILL MOVE INTO THE GREAT LAKES AREA SATURDAY
EVENING INTO MONDAY...BRINGING A CHANCE FOR RAIN SHOWERS INTO THE
CWA.
&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING)
ISSUED AT 753 PM EDT MON MAY 20 2013

AVIATION FCST WILL CONTINUE TO BE CHALLENING THRU THIS PERIOD. WITH
EASTERLY UPSLOPE WINDS DOMINATING AT KCMX THRU THE NIGHT...VLIFR
CONDITIONS WILL LIKELY CONTINUE TO PREVAIL. MAY SEE SOME IMPROVEMENT
TUE MORNING AND MAYBE MORE SO TUE AFTN AS LOW-LEVEL WINDS BACK A
LITTLE MORE TO THE NE AND DIMINISH THE UPSLOPING. EXPECT SOME SHRA
AT TIMES...ESPECIALLY THIS EVENING AND THEN TUE MORNING. AT KIWD...
SHRA OVER THE NEXT FEW HRS WILL RESULT IN OCNL MVFR CONDITIONS.
OTHERWISE...VFR CONDITIONS SHOULD FALL TO MVFR THAN IFR OVERNIGHT AS
WINDS SHIFT TO THE NE...BRINGING COOL/MOIST AIR OFF LAKE SUPERIOR.
MAY SEE IMPROVEMENT TO LOW MVFR TUE AFTN. AT KSAW...STRATUS PATCHES
LURKING TO THE E AND SE SHOULD SPREAD/EXPAND NW THIS EVENING AS
DAYTIME HEATING COMES TO AN END. EXPECT CONDITIONS TO FALL TO MVFR
THEN IFR BY MID/LATE EVENING. PERIOD OF SHRA/LIFR CONDITIONS WILL
OCCUR LATE TONIGHT/TUE MORNING AS DISTURBANCE LIFTS NE INTO THE
UPPER LAKES. WITH NE WINDS DURING THE DAY TUE...MAY NOT SEE
CONDITIONS IMPROVE ABOVE IFR AT KSAW.
&&

.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 500 AM EDT TUE MAY 21 2013

THE MAIN THREATS THROUGH THE PERIOD MARINE WISE WILL BE THE NW WINDS
FUNNELING OVER WESTERN LAKE SUPERIOR...WITH GUSTS OF 20-30KTS
THROUGH THIS EVENING. THE SECOND THREAT WILL BE THE CONTINUED FOG
THAT WILL LIKELY LINGER INTO WEDNESDAY MORNING...WHEN DRIER AIR
WORKS IN FROM THE NNW.

LOW PRESSURE OVER S MINNESOTA WILL CROSS INTO WISCONSIN AND NORTHERN
LAKE MICHIGAN THIS EVENING...BEFORE EXITING ACROSS LOWER MICHIGAN
AND THE LOWER GREAT LAKES WEDNESDAY AND WEDNESDAY NIGHT. IN THE
MEANTIME STRONG...DRY...AND COOL HIGH PRESSURE OVER N CANADA IS
EXPECTED TO SINK SOUTHWARD. THE RESULT WILL BE LIGHTER WINDS AS A
RIDGE MOVES OVERHEAD ON THURSDAY AND BUILDS SLIGHTLY ON FRIDAY. THE
RIDGE WILL LIKELY LINGER ACROSS THE GREAT LAKES REGION THROUGH AT
LEAST SATURDAY.
&&

.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
  DENSE FOG ADVISORY UNTIL 11 AM EDT THIS MORNING FOR MIZ001-003.

LAKE SUPERIOR...
  DENSE FOG ADVISORY UNTIL 8 PM EDT THIS EVENING FOR LSZ243>249-
     263>267.

  DENSE FOG ADVISORY FROM 8 AM EDT /7 AM CDT/ THIS MORNING TO 8 PM
     EDT /7 PM CDT/ THIS EVENING FOR LSZ162.

  GALE WARNING UNTIL 8 AM EDT /7 AM CDT/ THIS MORNING FOR LSZ162.

LAKE MICHIGAN...
NONE.
&&

$$

SHORT TERM...07
LONG TERM...MCD
AVIATION...ROLFSON
MARINE...KF