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000
FXUS63 KMQT 132338
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
738 PM EDT MON MAY 13 2013

.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 351 PM EDT MON MAY 13 2013

TWO WAVES/DISTURBANCES WILL BE THE FOCUS FOR THE FORECAST...WITH
THE FIRST ONE AFFECTING THE AREA TONIGHT AND THE OTHER TOMORROW
AFTERNOON/EVENING.

LATEST WV IMAGERY AND RUC ANALYSIS SHOWS THE AREA UNDER RIDGING
ALOFT AS THE UPPER TROUGH THAT HAD BEEN AFFECTING THE AREA THIS
WEEKEND SHIFTING EAST ACROSS QUEBEC AND AN UPPER RIDGE OVER THE
WESTERN CONUS. THERE IS A DECENT AMOUNT OF MOISTURE ROUNDING THE
RIDGE WITH A 996MB LOW JUST TO THE WEST OF LAKE WINNIPEG. CLOSER TO
HOME...SKIES WERE CLEAR OVER MUCH OF UPPER MICHIGAN THIS
MORNING...BUT INCREASING MID-HIGH CLOUDS ARE SPREADING ACROSS THE
AREA THIS AFTERNOON. BAND OF RAIN IS STARTING TO MOVE INTO WESTERN
LAKE SUPERIOR AT THIS TIME AND IS ASSOCIATED WITH A THIN AREA OF
800-500MB MOISTURE AND 700MB F-GEN.

EXPECT THE BAND TO CONTINUE EAST-SOUTHEAST THIS EVENING AS THE
700MB F-GEN AND BROAD 850-700MB WARM AIR ADVECTION CONTINUE.
BUT...WITH THE 500MB SHORTWAVE AND ASSOCIATED HEIGHT FALLS SHIFTING
EAST THROUGH ONTARIO AND WELL NORTH OF THE AREA ALONG WITH BEING
UNDER THE WRONG AREA OF THE UPPER JET /RIGHT EXIT/ THE BETTER
FORCING ISN/T OVER THE AREA. PLUS...WITH THE DRY AIR IT WILL BE
RUNNING INTO...WONDERING IF THAT WILL LIMIT THE INTENSITY SOME.
WITH AS PERSISTENT AS IT HAS BEEN TODAY...DID BUMP UP POPS A
TOUCH TO GET MORE CHANCE/SCATTERED WORDING IN FOR THIS
EVENING...BUT BASED OFF THE LIMITED RAIN AMOUNTS SEEN UPSTREAM
/TRACE TO A COUPLE HUNDREDTHS/ DIDN/T WANT TO GO MUCH ABOVE THAT. AS
ADDITIONAL 850-700MB MOISTURE SLIDES SOUTHEAST ACROSS THE EASTERN
CWA TONIGHT...WOULD THINK THE PRECIPITATION CHANCES SHOULD INCREASE
SOME OVERNIGHT. THERE IS LITTLE OR NO INSTABILITY WITH THIS PASSING
WAA...AS MID LEVEL LAPSE RATES ARE ONLY AROUND 3-5 C/KM...SO WILL
KEEP THUNDER OUT OF THE FORECAST. WITH THE BETTER CONSISTENCY IN
THIS MOISTURE ARRIVING OVER THE EAST...DID BUMP UP VALUES TO HIGH
CHANCE POPS THERE.

EXPECT TO SEE A BRIEF REPRIEVE ON TUESDAY MORNING BEHIND THE INITIAL
AREA OF WAA TONIGHT. THIS WILL LIKELY PRODUCE SOME BREAKS OR
CLEARING OVER AT LEAST THE WEST HALF OF THE CWA DURING THE MORNING
HOURS BEFORE MID-HIGH CLOUDS STREAM BACK INTO THE AREA. THEN...THE
SHORTWAVE THAT IS CURRENTLY ENTERING THE PACIFIC NORTHWEST WILL BE
MOVING EAST-NORTHEAST ALONG THE US/CANADIAN BORDER AND BE NEAR LAKE
WINNIPEG BY 18Z TUESDAY. WARM AIR ADVECTION WILL AGAIN BE ON THE
INCREASE FROM WEST TO EAST DURING THE AFTERNOON. MOISTURE WILL ALSO
BE LIMITED AS IT MOVES THROUGH THE AREA DURING THE AFTERNOON. BEST
MOISTURE AND CLOSEST PROXIMITY TO THE SHORTWAVE WILL BE OVER THE
NORTHWEST HALF OF THE CWA...SO WILL HAVE HIGHEST POPS THEIR DURING
THE LATTER PART OF THE AFTERNOON. QPF/REFLECTIVITY FROM HIGH
RESOLUTION MODEL RUNS SEEM TO MATCH THIS IDEA AND LEADS TO GREATER
CONFIDENCE.

ELEVATED INSTABILITY IS MARGINAL ALONG/NORTH THE WARM FRONT...WITH
THE BEST INSTABILITY FARTHER SOUTHWEST AND AHEAD OF THE COLD
FRONT. THIS IS LARGELY DUE TO THE MID-LEVEL LAPSE RATES STRUGGLING
TO GET ABOVE 6C/KM. THUS...THUNDER POTENTIAL WILL BE SLIM THROUGH
THE AFTERNOON HOURS. IF ANY ELEVATED THUNDERSTORMS
DEVELOP...WOULDN/T EXPECT THEM TO BE TOO STRONG...AS EFFECTIVE SHEAR
VALUES WILL LIKELY BE BELOW 30KTS THROUGH 00Z ACROSS ALL BUT THE FAR
SOUTHWEST CWA.

AFTER A COOL WEEKEND...TEMPERATURES HAVE STARTED TO REBOUND TODAY
AND EXPECT IT TO CONTINUE ON TUESDAY. THE WARM AIR ADVECTING INTO
THE AREA ON TUESDAY ALONG WITH INCREASING SOUTHERLY FLOW SHOULD LEAD
TO HIGHS IN THE LOWER 70S OVER THE FAR WEST AND A GRADIENT TO THE
50S OVER THE EAST HALF.

.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 351 PM EDT MON MAY 13 2013

MUCH OF THIS PERIOD WILL BE MARKED BY THE PRESENCE OF A 70KT OR
GREATER 250MB JET OVER UPPER MICHIGAN AND/OR LAKE SUPERIOR...AT
LEAST FROM TUESDAY NIGHT THROUGH SATURDAY MORNING. THIS WILL KEEP
THE AREA IN A RELATIVELY BUSY WEATHER PATTERN...IN BETWEEN THE DOME
OF HOT AIR OVER MUCH OF THE WESTERN HALF OF THE NATION...AND COLDER
AIR RESIDING OVER CANADA.

WE WILL START OUT TUESDAY NIGHT WITH A STACKED 500MB TROUGH-SFC LOW
SET UP JUST NORTH OF CYRL IN WESTERN MANITOBA. A COLD FRONT WILL
EXTEND S FROM THE SFC LOW...THROUGH THE EASTERN THIRD OF MN TO A
SECONDARY SFC LOW/TRIPLE POINT THAT MAY BE DEVELOPING NEAR KDLH.

THE LOCATION OF THE WARM FRONT IS KEY...LIKELY SET UP FROM THE
ARROWHEAD OF MN DOWN AND NEAR THE WI BORDER OF UPPER MI AT 00Z
WEDNESDAY. AS IS TYPICAL...THESE SPLITTING SYSTEMS CAN DEVELOP AND
ROB US OF MOISTURE...AS CONVECTION POPS UP OVER WI. EXPECT
WAA...LIMITED FORCING WILL LIKELY PERSIST...WITH MUCH OF THE BEST
FORCING CLOSER TO THE MAIN SFC/500MB TROUGH ACROSS ONTARIO /WHERE AN
AVERAGE QUARTER OF AN INCH OR MORE OF RAIN IS EXPECTED/. WE LOOK TO
BE IN A PRETTY CAPPED ENVIRONMENT...WITH THE BEST CHANCE FOR ANY
STRONGER SHOWERS OR THUNDERSTORMS OVER SOUTH CENTRAL AND EASTERN
UPPER MI DURING THE LATE EVENING HOURS...AND EVEN THEN LIKELY
ELEVATED ABOVE THE DRY AIR. THE SOUTHERN LOW/COLD FRONT WILL BE OVER
EASTERN UPPER MI/LAKE SUPERIOR BY 09Z WEDNESDAY...AND EAST OF UPPER
MI BY 12Z.

COOLER/DRIER AIR WILL SWEEP IN FOR WEDNESDAY...WITH 850MB TEMPS
FALLING FROM A MAX 14-18C OVERNIGHT TO AN AVERAGE 7-8C DURING THE
DAY WEDNESDAY. PW VALUES FALL TO 0.37 TO 0.44IN...OR 60-70 PERCENT
OF NORMAL...WITH THE LOWEST VALUES AWAY FROM THE KEWEENAW PENINSULA
AND EXTREME S CENTRAL UPPER MI. EXPECT A MORE MODERATED AIRMASS FROM
MUNISING EASTWARD AS MORE MOIST AIR SLIDES IN NEAR THE SHORELINE. A
WORST CASE SCENARIO...WITH THE NAM MIXING UP TO 650-700MB DURING THE
AFTERNOON HOURS...DEW POINTS MIXING DOWN INTO THE UPPER 20S
/F/ WOULD RESULT IN AFTERNOON MIN RH VALUES OF 19-25 PERCENT FROM
JUST E OF IWD TO NORTHERN DELTA COUNTY...WITH GUSTS 25-30KTS. ON A
POSITIVE NOTE...THE LATEST MODEL RUNS ARE NOT QUITE AS STRONG WITH
THE WINDS. WILL NEED TO WAIT AND SEE IF THIS TREND HOLDS. IF
LIMITED...OR NO...PRECIPITATION FALLS TUESDAY NIGHT...FIRE CONCERNS
WILL BE ELEVATED.

BEHIND THE ELONGATED LOW SHIFTING EAST INTO QUEBEC WEDNESDAY
NIGHT...DRY WEATHER WILL REMAIN THROUGH FRIDAY MORNING...WITH COOL
WEST TO NORTHWEST FLOW LINGERING. EXPECT THE RIDGE OF HIGH PRESSURE
TO BE DIRECTLY OVERHEAD ON THURSDAY...WITH LIGHT WINDS AND LAKE
BREEZES EXPECTED.

OUR NEXT WEATHER MAKER WILL BE ORGANIZING ACROSS THE CENTRAL PLAINS
FRIDAY NIGHT THROUGH SATURDAY...BEFORE SHIFTING TOWARD MN AND IA
SATURDAY NIGHT. THE SFC LOW WILL SIT AND SPIN BEFORE FINALLY EXITING
NORTHEASTWARD ACROSS W LAKE SUPERIOR AROUND 06Z MONDAY AND SOUTHERN
ONTARIO DURING THE DAY MONDAY...AS THE 500MB TROUGH/LOW DIVES ACROSS
THE NORTHERN PLAINS SUNDAY INTO SUNDAY NIGHT. ADDED TS CHANCES
SATURDAY THROUGH MONDAY MORNING...BEFORE THE END TO THE BULK OF
MOISTURE. AT THIS POINT IT LOOKS LIKE THERE WILL BE A GOOD CHANCE OF
SOAKING RAIN OVER THE FAR W PORTIONS OF UPPER MI FRIDAY NIGHT
THROUGH SATURDAY...WITH ANOTHER ROUND POSSIBLE LATER SUNDAY INTO
MONDAY AS THE COLD FRONT SWINGS THROUGH.

OTHER THAN SUNDAY TIMING DIFFERENCES BETWEEN THE 12Z RUNS OF THE GFS
AND ECMWF...THE FCST MODELS ARE IN NORMAL TO SLIGHTLY ABOVE NORMAL
AGREEMENT.
&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING)
ISSUED AT 737 PM EDT MON MAY 13 2013

VFR CONDITIONS TO PERSIST AT ALL THREE TAF SITES THROUGH THE
FORECAST. UPPER LEVEL DISTURBANCE PUSHING CLOUD COVER AND RAIN
SHOWERS INTO THE AREA THIS EVENING...BUT PRECIPITATION HAS BEEN VERY
SPOTTY DUE TO DRY AIR IN PLACE ASSOCIATED WITH RETREATING HIGH
PRESSURE. KIWD IS ON THE BACKSIDE OF THE BETTER FORCING AND THUS
HAVE REMOVED MENTION OF VCSH THERE...BUT KEPT IT IN FOR KCMX AND
KSAW. DISTURBANCE WILL SHIFT EAST OVERNIGHT WITH CLOUD COVER
DECREASING. WILL LEAVE IN MENTION OF LLWS AT KSAW AND KIWD AS BUFKIT
SOUNDINGS SHOW STRONG WINDS ALOFT THIS EVENING AS THE DISTURBANCE
MOVES THROUGH. NEXT DISTURBANCE APPROACHES THE REGION IN THE MORNING
WITH INCREASING HIGH AND MID LEVEL CLOUDS...WITH A POSSIBILITY OF
LIGHT SHOWERS OVER KCMX BY 0Z. HAVE LEFT OUT OF FORECAST FOR NOW AS
TIMING OF ARRIVAL MAY BE DELAYED SLIGHTLY BEYOND THE CURRENT
FORECAST PERIOD.

&&

.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 351 PM EDT MON MAY 13 2013

HIGH PRESSURE WILL DEPART THE AREA THIS EVENING. THIS WILL LEAD TO
INCREASING SOUTHERLY FLOW TONIGHT INTO TUESDAY AHEAD OF A LOW
PRESSURE SYSTEM MOVING EAST THROUGH SOUTHERN CANADA. AT THIS
POINT...THE INCREASING WARM AIR ABOVE THE SURFACE SHOULD LIMIT GUST
TO 20KTS IN MOST LOCATIONS FOR OVERNIGHT TONIGHT AND TUESDAY.
DISPITE A COUPLE OF SIGNIFICANT SYSTEMS PUSHING THROUGH THE AREA
TUESDAY-TUESDAY NIGHT...AND AGAIN THIS WEEKEND...WINDS ARE CURRENTLY
ANTICIPATED TO REMAIN BELOW 30KTS. IT IS THAT TIME OF YEAR
AGAIN...THERE WILL BE A ROUND OF THUNDERSTORMS POSSIBLE TUESDAY
AFTERNOON OVER WESTERN LAKE SUPERIOR...PUSHING EASTWARD OVERNIGHT
AND ENDING EARLY WEDNESDAY. ANOTHER ROUND OF THUNDERSTORMS WILL BE
POSSIBLE WEST ON SATURDAY/SATURDAY NIGHT...AND ACROSS ALL OF LAKE
SUPERIOR SUNDAY THROUGH MONDAY MORNING.
&&

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

$$

SHORT TERM...SRF
LONG TERM...KF
AVIATION...RJT
MARINE...SRF/KF