000
FXUS63 KMQT 191731
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
131 PM EDT SUN MAY 19 2013

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 440 AM EDT SUN MAY 19 2013

UPPER AIR PATTERN CONSISTS OF A SHORTWAVE IN NORTHERN LAKE SUPERIOR
WHICH HAS BEEN KICKING OFF SOME SCATTERED SHOWERS OVER THE AREA
EARLY THIS MORNING. THIS SHORTWAVE IS OVER THE TOP OF A RIDGE OVER
THE GREAT LAKES REGION. THERE IS ALSO A TROUGH OVER THE ROCKIES
WHICH IS SLOWLY MOVING INTO THE NORTHERN PLAINS THIS MORNING WITH
PLENTY OF MCC/MCS ACTIVITY WITH IT WELL OFF TO THE WEST. THIS TROUGH
MOVES SLOWLY TO THE EAST AND FORMS A CLOSED 500 MB LOW OVER IT TODAY
OVER THE NORTHERN PLAINS WHICH MOVES SLOWLY CLOSER. GFS...NAM AND
ECMWF SHOW 850-500 MB Q-VECTOR CONVERGENCE REMAINING OVER THE AREA
THIS PERIOD WITH SOME DEEPER MOISTURE.

COMPLICATED FORECAST FOR THIS FORECAST PERIOD AS CLOUD COVER WILL BE
HARD TO JUDGE WHICH OF COURSE WILL HAVE AN EFFECT ON TEMPERATURES.
850 MB TEMPERATURES OF 14C MIXED DOWN TO THE SFC WOULD GIVE ME HIGHS
IN THE UPPER 70S. LOWERED HIGHS FOR THAT REASON AND ALSO THINK THERE
WILL BE A LOT OF HIGH CLOUDS AROUND FROM CIRRUS BLOWOFF FROM
CONVECTION TO THE WEST. LOWERED HIGHS ABOUT 5 DEGREES TO ACCOUNT FOR
THIS. OTHER THING TO CONSIDER IS OVER THE EAST FOR TODAY. THERE
COULD BE SOME LAKE BREEZE CONVERGENCE AND WOULD NOT BE SURPRISED TO
SEE SOME CONVECTION KICKED OFF ESPECIALLY THIS AFTERNOON WHERE THE
LAKE BREEZES INTERSECT. FOR THIS REASON...HAVE AN EAST TO WEST
ORIENTED POP BAND AND HAVE SLIGHT CHANCE POPS IN THE EAST FOR THIS
REASON. THE WEST AND NORTH WILL HAVE THE HIGHEST POPS FOR TODAY WITH
IT DRY ACROSS THE FAR SOUTH. FOR TONIGHT...WIDESPREAD CONVECTION
LOOKS LIKELY AND HAVE HIGH POPS FOR THIS WITH THE SPREAD FROM WEST
TO EAST. WITH EAST TO NORTHEAST WINDS...ADJUSTED SOME TEMPERATURES
NEAR LAKE SUPERIOR DOWNWARD FOR LOWS TONIGHT.

.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 440 AM EDT SUN MAY 19 2013

THE WEATHER LOOKS RELATIVELY UNSETTLED THROUGH THE FIRST HALF OF THE
UPCOMING WORK WEEK. CONFIDENCE IS HIGH THAT THERE WILL BE PERIODIC
BOUTS OF SHOWERS AND PERHAPS EVEN SOME THUNDER EARLY IN THE WEEK.
THE CHALLENGE IN THE FORECAST IS PINPOINTING THE WINDOWS WHEN THE
RAIN CHANCES WILL BE THE HIGHEST AS IT WILL NOT BE RAINING THE
ENTIRE TIME THROUGH WEDNESDAY.

THE INTERACTION OF THE CENTRAL PLAINS UPPER/SFC LOW WITH A STATIONARY
BOUNDARY DRAPED JUST SOUTH OF THE AREA WILL BE THE MAIN
PRECIPITATION TRIGGERING MECHANISMS THROUGH MIDWEEK.  CONTINUED WARM
ADVECTION OVER THE LOW LEVEL BOUNDARY COMBINED WITH UPPER LEVEL
DIVERGENCE...AMPLE MOISTURE...AND SPOKES OF SHORTWAVE ENERGY
ROTATING AROUND THE UPPER LOW WILL LEAD TO 1 TO 3 INCH RAINFALL
TOTALS...HEAVIEST WEST...FROM SUNDAY NIGHT THROUGH WEDNESDAY.
SHORTWAVE TIMING IS A CHALLENGE ESPECIALLY WITH CONVECTIVE TRENDS TO
THE SOUTH AND WEST ADDING ADDITIONAL UNCERTAINTY...BUT MODELS
GENERALLY AGREE THAT DURING THE DAY MONDAY AND AGAIN ON TUESDAY MAY
BE TIMES WITH SLIGHTLY HIGHER RAINFALL CHANCES.

SINCE THE FORECAST AREA WILL REMAIN ON THE COOL SIDE OF THE SURFACE
BOUNDARY THERE SHOULD NOT BE MUCH OF A THREAT FROM STRONG
THUNDERSTORMS BUT RUMBLES OF THUNDER ARE QUITE POSSIBLE FROM MONDAY
INTO TUESDAY.

BY LATE WEDNESDAY INTO THURSDAY DRIER AIR PUSHING INTO THE AREA FROM
CANADA SHOULD BE ENOUGH TO PUSH THE PRECIPITATION OFF TO THE SOUTH.
DRY WEATHER WILL THEN PERSIST INTO NEXT WEEKEND.

WITH LOW LEVEL WINDS EXPECTED TO REMAIN OUT OF THE EAST AND THEN
NORTHEAST DURING THE WEEK DAYTIME TEMPERATURES WILL REMAIN 5 TO 10
DEGREES BELOW NORMAL...ESPECIALLY CLOSE TO LAKE SUPERIOR.
&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 131 PM EDT SUN MAY 19 2013

EXPECT VFR CONDITIONS TO BE IN PLACE FOR THE REST OF THE
AFTERNOON...AS THE MAIN FORCING THAT LED TO THE SHOWERS OVER
CENTRAL/NORTHERN LAKE SUPERIOR HAS SHIFTED NORTH OF THE TAF SITES.
THERE IS A LOW POTENTIAL FOR SOME SHOWERS DEVELOPING THIS
AFTERNOON...BUT THINKING THAT THE CLOUDS THAT ARE IN PLACE WILL
INHIBIT DEVELOPMENT.

UNCERTAINTY GROWS HEADING INTO TONIGHT AND MONDAY...AS IT WILL
LARGELY DEPEND ON CONVECTION DEVELOPING IN SOUTHEAST MN THIS
AFTERNOON. WOULD THINK THIS WOULD MOVE NORTH-NORTHEAST THIS EVENING
AND HAVE THE BEST OPPORTUNITY TO AFFECT KIWD...THEN KCMX.
CONFIDENCE IS LOWER FOR IT AFFECTING KSAW TONIGHT...AS THERE IS
UNCERTAINTY ON HOW FAR EAST IT WILL TRACK. SHOWER POTENTIAL DOES
INCREASE FOR KSAW TOWARDS DAYBREAK AS FORCING INCREASES ACROSS THE
AREA.

FINALLY...THERE IS THE POTENTIAL FOR FOG AT KSAW/KCMX. KCMX
HAS THE BEST CHANCE...BUT CONFIDENCE ON TIMING IS LOW BASED OFF
CURRENT FOG EXTENT /DUE TO CLOUD COVER OVER THE LAKE/ AND LIMITED
SHIP REPORTS OF FOG OVER EASTERN LAKE SUPERIOR. BUT WITH THE
SHOWERS OVER THE EASTERN LAKE THIS MORNING AND FOG OVER THE WESTERN
LAKE...WOULD EXPECT THE AREA TO EXPAND TONIGHT AND HAVE BROUGHT
CONDITIONS DOWN TO IFR/LIFR. KSAW IS EVEN MORE UNCERTAIN...SO
DELAYED THE START TIME UNTIL THE OVERNIGHT HOURS.
&&

.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 440 AM EDT SUN MAY 19 2013

WILL HAVE TO WATCH FOG DEVELOPMENT ON THE LAKE BECAUSE IT IS THICK
IN A FEW PLACES ACROSS THE WEST THIS MORNING. OVER THE EAST...HAS
NOT DEVELOPED YET. IF FOG GETS MORE WIDESPREAD...WILL HAVE TO ISSUE
A DENSE FOG ADVISORY FOR THE WEST HALF OF LAKE SUPERIOR. HEADING
THRU EARLY NEXT WEEK...THE PRESSURE GRADIENT OVER THE UPPER LAKES
WILL SLOWLY TIGHTEN BETWEEN LOW PRESSURE SLOWLY MOVING FROM THE WRN
PLAINS TOWARD THE UPPER MISSISSIPPI VALLEY AND HIGH PRESSURE
BUILDING IN THE VICINITY OF WRN HUDSON BAY. THIS WILL LEAD TO
EASTERLY WINDS GRADUALLY INCREASING TO ALMOST 30 KNOTS BY MON AND
MON NIGHT...ESPECIALLY OVER WRN LAKE SUPERIOR WHERE
FUNNELING/CHANNELING WILL ENHANCE THE WINDS. THE LOW PRESSURE SYSTEM
WILL SLIDE SOUTH OF LAKE SUPERIOR WED...BUT THE PRESSURE GRADIENT
WILL BE WEAKER THAN EARLIER IN THE WEEK...SO LIGHTER ELY WINDS ARE
EXPECTED.
&&

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

$$

SHORT TERM...07
LONG TERM...MZ
AVIATION...SRF
MARINE...07