Area Forecast Discussion
Issued by NWS Marquette, MI

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FXUS63 KMQT 231736
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
136 PM EDT WED JUL 23 2014

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 411 AM EDT WED JUL 23 2014

CURRENTLY...THE CWA IS BENEATH A BROAD UPPER TROUGH THAT EXTENDS
FROM A LOW JUST E OF HUDSON BAY. AT THE SFC...THE CWA SITS BETWEEN A
1012MB TROUGH OVER THE LOWER GREAT LAKES AND A 1024MB HIGH CENTERED
OVER SRN MANITOBA. WITH THE SFC HIGH BECOMING INCREASINGLY DOMINANT
THROUGH TONIGHT AND NO SIGNIFICANT UPPER LEVEL ENERGY EXPECTED TO
PASS OVERHEAD...THE SHORT TERM FORECAST IS FAIRLY QUIET. FOCUSED ON
SFC MOISTURE TODAY AND MIN TEMPS TONIGHT.

ON THAT NOTE...DECENT MIXING AND AN OVERALL DRY AIRMASS WILL ALLOW
DEW PTS TO FALL INTO THE MID 40S INLAND AS TEMPS MAX OUT AROUND
70S...RESULTING IN INLAND MIN RH VALUES THIS AFTERNOON IN THE LOW TO
MID 40 PERCENT RANGE. WINDS THIS AFTERNOON WILL GENERALLY BE AROUND
10KTS /A COUPLE KTS LOWER W AND HIGHER E/ WITH GUSTS RANGING FROM
12KTS W TO 20KTS E.

WITH THE SFC HIGH CENTER MOVING INTO WI TONIGHT...WILL NOT SEE MUCH
IN THE WAY OF CLOUD COVER. WINDS WILL BE LIGHT AND THE OVERHEAD
AIRMASS FAIRLY DRY /PWATS AROUND 0.5 INCHES OR AROUND 50 PERCENT OF
NORMAL/. WENT WITH THE LOW END OF GUIDANCE FOR MIN TEMPS
TONIGHT...WHICH RESULTED IN LOW TEMPS IN THE MID 30S OVER THE
INTERIOR W AND IN THE 40S ELSEWHERE. ADDED SOME PATCHY FROST OVER
ERN GOGEBIC COUNTY WHERE TEMPS ARE FORECAST TO BE COLDEST.

.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 451 AM EDT WED JUL 23 2014

AMPLIFIED MID/UPPER LEVEL RIDGE EXTENDING FROM THE SRN ROCKIES INTO
NCNTRL CANADA HAS LED TO ERN NAMERICA TROF AMPLIFICATION AND THUS A
RETURN TO COOLER WEATHER OVER THE UPPER LAKES. OVER THE NEXT FEW
DAYS...MID/UPPER LEVEL LOW OFF THE PACIFIC NW COAST WILL MOVE E...
CUTTING THRU THE RIDGE AXIS AND RESULTING IN SOME DEAMPLIFICATION OF
THE ERN NAMERICA TROF INTO THE ERN CONUS. MEANWHILE...A HEALTHY
POSITIVE HEIGHT ANOMALY WILL REMAIN OVER NCNTRL CANADA. AS THE
MIDLEVEL LOW CONTINUES TO MOVE E AND OPENS UP...THE POSITIVE ANOMALY
OVER NCNTRL CANADA WILL QUICKLY RECONNECT WITH THE RIDGE OVER THE
SRN ROCKIES. THIS IN TURN WILL FORCE SIGNIFICANT REAMPLIFICATION OF
THE ERN NAMERICA TROF EARLY NEXT WEEK...AIDED BY THE REMNANT MID
LEVEL LOW ENERGY FORCED TO THE SE. THIS AMPLIFIED TROF WILL BE
ANOTHER UNUSUALLY DEEP TROF FOR JULY AS 500MB HEIGHTS ARE FCST TO
BOTTOM OUT 2.5-3 STANDARD DEVIATIONS BLO THE LONG TERM JULY AVG IN
THE OHIO VALLEY AND CNTRL/SRN APPALACHIAN AREA. MAGNITUDE OF
ANOMALIES SUGGEST SOME RECORD BREAKING COOL WEATHER WILL BE POSSIBLE
IN THE ERN CONUS. THUS...AS WE HEAD TO THE END OF JULY...COOL
WEATHER/BLO NORMAL TEMPS WILL BE THE RULE FOR THE UPPER LAKES REGION
DURING THE EARLY THRU AT LEAST MID WEEK PERIOD NEXT WEEK. THE COOL
WEATHER WILL LIKELY PUT THIS JULY INTO THE TOP 10 COOLEST ON RECORD
HERE AT THE NWS OFFICE LOCATION. AS FOR PCPN...AFTER 2-3 DAYS OF DRY
WEATHER...PCPN CHANCES WILL INCREASE OVER THE WEEKEND AS THE
AFOREMENTIONED MIDLEVEL LOW OR REMNANT ENERGY PASSES THRU THE GREAT
LAKES REGION. NEXT WEEK...PCPN CHANCES WILL REVOLVE AROUND WHERE
AXIS OF HIGHLY AMPLIFIED TROF SETS UP AND/OR WHETHER A MID LEVEL LOW
ENDS UP FORMING IN THE GREAT LAKES REGION.

BEGINNING THU...A SHORTWAVE DROPPING INTO THE ERN TROF WILL LIKELY
TRIGGER SCT SHRA/TSRA IN NRN ONTARIO TO THE N AND E OF LAKE
SUPERIOR. OVER UPPER MI...QUIET WEATHER WILL CONTINUE WITH SFC HIGH
PRES LINGERING OVER THE WRN GREAT LAKES. DRY AIRMASS WITH ABUNDANT
SUNSHINE WILL RESULT IN DEEP MIXING UPWARDS OF 800-750MB WHICH
YIELDS MAX TEMPS IN THE UPPER 70S/AROUND 80F AWAY FROM LAKE
MODERATION. GIVEN DRY COLUMN...INCORPORATED INTO THE FCST LOWER
DWPTS OBTAINED FROM THE EXPECTED DEEP MIXING.

THU NIGHT/FRI...MID LEVEL LOW CURRENTLY OFF THE PACIFIC NW COAST IS
FCST TO ROLL INTO SRN SASKATCHEWAN. AS THIS FORCES WEAKENING OF THE
DOWNSTREAM RIDGE...SEVERAL WEAK SHORTWAVES ARE INDICATED TO MOVE
ACROSS THE NRN PLAINS TO THE GREAT LAKES. WITH THE MAIN BAROCLINIC
ZONE OFF TO THE SW AND W...BELIEVE PCPN ASSOCIATED WITH ANY OF THE
WAVES WILL STAY W AND SW OF UPPER MI...BUT THERE WILL BE AN INCREASE
IN CLOUD COVER WITH TIME FROM W TO E. WITH LIGHT WINDS AND STILL
LIMITED CLOUD COVER...FAVORED THE LOWER END OF GUIDANCE FOR MINS THU
NIGHT (UPPER 40S IN TRADITIONAL COLD SPOTS). HIGHS FRI SHOULD BE
SIMILAR TO THU.

OVER THE WEEKEND...MIDLEVEL LOW THAT WILL BE OVER SASKATCHEWAN FRI
WILL OPEN UP AND TRACK ESE INTO THE GREAT LAKES. AT THE SFC...MODELS
INDICATE A COMPLEX/DISORGANIZED SFC PATTERN WITH AT LEAST ONE WEAK
SFC LOW MOVING ESE ACROSS THE WRN GREAT LAKES. A COUPLE OF PERIODS
OF BETTER DEEP LAYER FORCING ARE INDICATED...ONE SAT MORNING AND THE
OTHER SAT NIGHT/SUN MORNING...SUGGESTING THESE WILL BE THE PERIODS
WITH BEST SHOT OF MORE WIDESPREAD PCPN. FOR NOW...FCST WILL SHOW
INCREASING CHC POPS FRI NIGHT...MAINLY OVER THE W...AND THEN CHC
POPS SAT THRU SUN WITH HIGHEST POPS SAT NIGHT/SUN MORNING.
POPS WILL LIKELY NEED TO BE INCREASED FOR SAT NIGHT/SUN MORNING IF
MODELS MAINTAIN CONTINUITY ON TIMING. THERE IS ACTUALLY FAIRLY GOOD
AGREEMENT ON THE MAIN PIECE OF ENERGY EXITING SUN...SO PCPN SHOULD
WIND DOWN/END FROM NW TO SE SUN AFTN/EVENING. WITH NEGATIVE
SHOWALTER INDEX AND SOME ELEVATED INSTABILITY...THERE SHOULD BE AT
LEAST ISOLD TSTMS FRI NIGHT THRU SAT NIGHT AND POSSIBLY INTO SUN
MORNING AS WELL. SUN COULD BE QUITE COOL WITH PCPN FOR PART OF THE
DAY ALONG WITH BRISK NRLY WINDS OFF LAKE SUPERIOR...ESPECIALLY FROM
THE KEWEENAW EASTWARD. LAKESIDE LOCATIONS MAY NOT SEE TEMPS GET OUT
OF THE 50S. EVEN WELL INLAND...TEMPS MAY NOT RISE ABOVE 70F...BUT
THAT WILL DEPEND ON CLOUD COVER.

MON/TUE...AS ALLUDED TO EARLIER...PCPN FCST WILL DEPEND ON WHERE
AXIS OF HIGHLY AMPLIFIED TROF SETS UP AND/OR WHETHER A MID LEVEL LOW
ENDS UP FORMING IN THE GREAT LAKES REGION. LATEST GUIDANCE AND
TRENDS SUGGEST TROF AXIS MAY BE FAR ENOUGH E TO LIMIT PCPN CHANCES.
AT THIS POINT...FCST WILL NOT INCLUDE AN EXPLICIT MENTION OF PCPN
GIVEN LACK OF A SIGNAL FOR ANYTHING ORGANIZED IN ASSOCIATION WITH A
SHORTWAVE.
&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 136 PM EDT WED JUL 23 2014

WITH HIGH PRESSURE MOVING INTO UPPER MI...PRIMARILY VFR CONDITIONS
ARE EXPECTED AT ALL SITES THROUGH THE FORECAST PERIOD. KCMX MAY SEE
SOME FOG DEVELOP LATE TONIGHT AFTER 6Z WITH LOW LEVEL MOISTURE
TRAPPED BENEATH THE INVERSION...THOUGH CONFIDENCE IS NOT VERY HIGH.
FOR NOW...DROPPED VISIBILITY DOWN TO 3 MILES DURING THIS TIME. LATER
SHIFTS MAY ADJUST ONCE THEY OBSERVE FOG DEVELOPING.
&&

.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 411 AM EDT WED JUL 23 2014

AS HIGH PRESSURE MAKES ITS WAY INTO THE AREA TODAY...WINDS WILL
CONTINUE TO LIGHTEN UP. A MORE UNSETTLED PATTERN WILL MOVE INTO THE
REGION THIS WEEKEND INTO NEXT WEEK...POSSIBLY BRINGING A SERIES OF
WEAK LOWS AND TROUGHS TO THE UPPER GREAT LAKES. AT THIS TIME WINDS
ARE EXPECTED TO REMAIN BELOW 20KTS THROUGH THE FORECAST PERIOD.
&&

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

$$

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





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