Forecast Discussions mentioning any of "HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 04/30/13

AREA FORECAST DISCUSSION

NWS CHARLESTON SC

 423 PM EDT SUN APR 28 2013

.SYNOPSIS...
HIGH PRESSURE WILL CONTINUE TO WEAKEN TONIGHT...AS SEVERAL MID
LEVEL DISTURBANCES PROGRESS OVER OR NEAR THE LOCAL AREA. AN UPPER
LEVEL TROUGH OF LOW PRESSURE WILL ADVANCE THROUGH THE REGION BY
TUESDAY...AS STRENGTHENING HIGH PRESSURE BUILDS FROM THE NORTH THE
SECOND PART OF THE WEEK.

&&

.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
ISOLATED TO SCATTERED SHOWERS ARE CURRENTLY FOUND ACROSS THE FAR
SOUTHWEST ZONES THIS AFTERNOON..THE EXCEPTION BEING SOME SHOWER
ACTIVITY ORIGINATING FROM THE NEARBY ATLANTIC THAT PUSHED INTO THE
CHARLESTON COUNTY COAST FROM CONVERGENCE OFFSHORE. NUMERICAL MODEL
SOLUTIONS HAVE STRUGGLED TO ACCURATELY REPRESENT THE COVERAGE OF
PRECIPITATION TODAY...RESULTING IN LOWER CONFIDENCE WITH THE
EVOLUTION OF ONGOING SHOWER ACTIVITY AND THE INITIATION OF NEW
CONVECTION. ONLY THE HIGH RESOLUTION HRRR MODEL SEEMS TO HAVE A
DECENT OVERVIEW OF THE SHOWER COVERAGE...AND WILL THUS LEAN TOWARD
ITS REPRESENTATION OF THE PRECIPITATION SCENARIO FOR THE NEAR TERM
PERIOD.

SHOWERS CURRENTLY IN THE AREA HAVE STRUGGLED TO INTENSIFY WITHIN
ONLY MARGINAL INSTABILITY SEEN IN MOST RECENT STORM PREDICTION
CENTER MESOANALYSIS. THE STRONGEST SHORTWAVE ENERGY DOWNSTREAM OF
THE MAIN UPPER TROUGH TO THE WEST HAS REMAINED TO THE WEST AND
NORTHWEST OF THE FORECAST AREA. HOWEVER...CONSIDERING SEVERAL MORE
HOURS OF DAYLIGHT MAINTAINING SOME INSTABILITY...AS WELL AS THE
POTENTIAL SEABREEZE AND OUTFLOW BOUNDARY INTERACTIONS...INLAND
THUNDERSTORMS COULD CONTINUE TO DEVELOP AND POSSIBLY INTENSIFY
THROUGH THE AFTERNOON. ANY STORMS THAT BECOME STRONG AND ORGANIZED
COULD PRODUCE GUSTY WINDS AND SMALL HAIL...ESPECIALLY WHERE
BOUNDARY INTERACTIONS OCCUR.

EVEN WITH A POTENTIAL LULL IN RAIN COVERAGE THIS EVENING AFTER
DIURNAL INSTABILITY HAS WANED...THE APPROACHING UPPER TROUGH WILL
FINALLY BE ABLE TO SUPPRESS RIDGING ALONG THE EAST COAST AND ALLOW
SHORTWAVE ENERGY TO CROSS INTO THE FORECAST AREA. AT THAT
POINT...NUMERICAL MODELS ARE IN GOOD AGREEMENT THAT MORE
WIDESPREAD PRECIPITATION WILL IMPACT THE REGION. WILL SHOW
INCREASING RAIN CHANCES FROM WEST TO EAST ACCORDINGLY...WHILE
MAINTAINING MENTION OF JUST A SLIGHT CHANCE FOR THUNDER OVERNIGHT.

WARM ADVECTION WITHIN SOUTHERLY FLOW OVERNIGHT...COMBINED WITH THE
INSULATING EFFECTS OF THICK CLOUD COVER...WILL KEEP LOW
TEMPERATURE QUITE MILD. EXPECT TEMPERATURES TO ONLY FALL INTO THE
LOW TO MID 60S.

&&

.SHORT TERM /6 AM MONDAY MORNING THROUGH WEDNESDAY/...
MODELS CONTINUE TO INDICATE THE POTENTIAL FOR UNSETTLED WEATHER
THROUGH THIS PERIOD. FOR MONDAY...AND UPPER LEVEL TROUGH WILL BE
WEAKENING AS IT MOVES NORTH AND EAST OF THE REGION. AMPLE MOISTURE
AND SOME WEAK LIFT ASSOCIATED WITH UPPER TROUGH SHOULD BE ENOUGH
TO SPARK NUMEROUS SHOWERS AND SOME THUNDERSTORMS...ESPECIALLY DURING
PEAK AFTERNOON HEATING. HAVE MAINTAINED HIGH END LIKELY TO LOW END
CATEGORICAL POPS...WITH THE HIGHEST POPS OVER THE NORTHERN/SC ZONES.
PW VALUES AROUND 1.5 INCHES...ALONG WITH DEEP LAYER SSW FLOW COULD
TRANSLATE INTO THE CHANCE FOR SOME LOCALLY HEAVY RAINFALL.

THE FORECAST PROBLEM BEGINNING AS SOON AS MONDAY NIGHT IS THAT THE
GLOBAL MODELS BEGIN TO DIVERGE FROM THE GRIDDED/NAM MODEL. THE
GENERAL TREND IN THE GLOBAL MODELS IS TO MOVE THE UPPER TROUGH WELL
NE OF THE REGION LATE MONDAY NIGHT THROUGH TUESDAY NIGHT...TAKING
WITH IT THE BULK OF THE DEEP LAYER MOISTURE AND PRECIP CHANCES.
HOWEVER...THE NAM IS SLOWER WITH MOVING OUT THE UPPER TROUGH TO THE NE
AND ALSO HOLDS A MUCH STRONGER INVERTED TROUGH OVER THE NEARSHORE
ATLANTIC WATERS THROUGH MID WEEK. THE STRONGER SURFACE INVERTED
TROUGH OVER THE ATLANTIC WATERS SEEMS TO BE IN RESPONSE TO A
DEVELOPING WEAK/CLOSED UPPER LOW TO THE SW OVER THE GULF STATES.
THEREFORE...THE NAM SOLUTION LOOKS MUCH WETTER THROUGH THE PERIOD
THAN THE GLOBAL MODELS. FOR NOW...HAVE TRENDED POPS UP FROM PREVIOUS
FORECAST...GENERALLY IN THE CHANCE RANGE...BUT STILL MUCH LOWER THAN NAM
WOULD SUGGEST.

STABILITY PROFILES SEEM PRETTY MARGINAL TO SUPPORT MUCH THUNDER
THROUGH THE PERIOD...BUT HAVE KEPT CHANCE TO SLIGHT CHANCE MAINLY IN
THE AFTERNOONS.

THE TEMPERATURE FORECAST IS CHALLENGING DUE TO THE UNCERTAINTY IN
PRECIP CHANCES AND CLOUD COVER DEPICTED BY THE MODELS. HAVE MADE
ONLY SLIGHT CHANGES TO THE PREVIOUS FORECASTS...GENERALLY UPPER 70S
TO NEAR 80 AND UPPER 50S TO LOWER 60S FOR LOWS. THESE VALUES ARE
NEAR NORMAL. WILL NEED TO MONITOR LATER FORECAST TRENDS...SINCE A
SOLUTION MORE LIKE THE NAM WOULD LIKELY TRANSLATE INTO LOWER MAXES
AND HIGHER MINS.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
MODERATE TO HIGH FORECAST UNCERTAINTY CONTINUES INTO THE EXTENDED
PERIOD. AN IMPRESSIVE BLOCKING PATTERN WILL PREVAIL OVER THE EASTERN
CONUS INTO NEXT WEEKEND. THE SOUTHERN EXPANSE OF THE BLOCKING RIDGE
AND ASSOCIATED INTERACTION OF THE UPPER LOWS OVER THE LOWER
MISSISSIPPI RIVER VALLEY...THE WESTERN ATLANTIC AND THE GREAT PLAINS
REMAINS UNCLEAR. DID SOME MINOR TWEAKS TO THE POPS/WINDS/TEMPS
THROUGH THURSDAY NIGHT TO BLEND BETTER WITH THE SHORT TERM FORECAST.
HOWEVER...MAINTAINED SLIGHT CHANCE/CHANCE POPS THROUGH THE PERIOD
ESPECIALLY GIVEN THE 28/00Z EUROPEAN SOLUTION DEPICTING A PERSISTENT
BAND OF MOISTURE ON THE SOUTHERN PERIPHERY OF THE RIDGE/OVER OR
CLOSE TO SOUTH/WESTERN COUNTIES OF THE FORECAST AREA
WEDNESDAY/THURSDAY...FOLLOWED BY EASTERN PROGRESSION OF THE GREAT
PLAINS UPPER LOW TOWARD THE EAST PUSHING ENHANCED MOISTURE FARTHER
INTO THE FORECAST AREA LATE WEEK/NEXT WEEKEND. HOWEVER...IF THE DEEP
LAYER BLOCKING RIDGE EXPANDS FARTHER SOUTH ACROSS THE
REGION...MOISTURE COULD BE FORCED OUTSIDE THE FORECAST AREA
RESULTING IN DRIER CONDITIONS.

&&

.AVIATION /19Z SUNDAY THROUGH FRIDAY/...
VFR IS EXPECTED FOR MUCH OF THE PERIOD...HOWEVER MODEL SOUNDINGS AND
GUIDANCE ONCE AGAIN HINT AT MVFR CEILINGS DEVELOPING OVERNIGHT
INTO MONDAY MORNING. CONFIDENCE IN THIS OCCURRING IS TOO LOW TO
MENTION AT THIS TIME...AND WILL JUST LEAN TOWARD THIS POTENTIAL BY
INCLUDING SCATTERED MVFR CLOUDS LATE TONIGHT. THE OTHER AVIATION
CONCERN IS SHOWERS AND THUNDERSTORMS AFFECTING THE TERMINALS.
MODELS ARE STILL NOT HANDLING CURRENT SITUATION VERY WELL...SO
DETERMINING COVERAGE AND TIMING IS QUITE DIFFICULT. WILL NEED TO
MONITOR THIS AFTERNOON...AND AMENDMENTS WILL LIKELY BE NEEDED AS
TRENDS BECOME BETTER DEFINED. REDUCED VSBYS/CIGS ARE POSSIBLE
WITHIN HEAVIER RAINFALL.

EXTENDED AVIATION OUTLOOK...OCCASIONAL FLIGHT RESTRICTIONS POSSIBLE
DUE TO SHOWERS/RICH LOW LEVEL MOISTURE MONDAY INTO TUESDAY MORNING.
VFR CONDITIONS SHOULD THEN PREVAIL MUCH OF THE TIME THROUGH LATE
WEEK...BUT FORECAST CONFIDENCE IS NOT HIGH.

&&

.MARINE...
TONIGHT...SURFACE HIGH PRESSURE TO THE NORTH WILL RETREAT FARTHER
INTO THE ATLANTIC. MODERATE SOUTHEAST FLOW WILL STEADILY VEER MORE
TO THE SOUTH TONIGHT. THE PRESSURE GRADIENT WILL TIGHTEN SUFFICIENTLY
TO SUPPORT WIND SPEEDS AT 15 KT OVERNIGHT WITH A FEW GUSTS TO 20 KT.
FOR THE MOST PART...SIGNIFICANT WAVE HEIGHTS WILL REMAIN CAPPED AT
4 OR 5 FT. MARINERS CAN EXPECT ISOLATED TO SCATTERED SHOWERS
TONIGHT WITH A SLIGHT CHANCE FOR THUNDER.

MODELS SHOW A CONSIDERABLE AMOUNT OF UNCERTAINTY THROUGH MUCH OF THE
WEEK. THE NAM HOLDS A STRONGER SURFACE COASTAL TROUGH OF LOW
PRESSURE OVER THE NEARSHORE WATERS LATER TUESDAY THROUGH AT LEAST
WEDNESDAY. HOWEVER...THE GLOBAL MODELS ALL INDICATE A MUCH WEAKER
COASTAL TROUGH OF LOW PRESSURE...WHILE BUILDING STRONGER HIGH
PRESSURE IN FROM THE NORTH. THIS MAKES FOR A DIFFICULT WIND
FORECAST. FOR NOW...HAVE BLENDED THE MODEL SOLUTIONS AS BEST AS
POSSIBLE...WHICH ALSO COLLABORATES REASONABLY WELL WITH SURROUNDING
OFFICES.

FOR MONDAY AND MONDAY NIGHT...KEPT SOUTHERLY WINDS OF GENERALLY
15 KT OR LESS WITH SEAS 3 TO 5 FT. THE GFS IS INDICATING SEAS
COULD REACH 6 FT OFFSHORE GA...BUT HAVE CAPPED TO 5 FT DUE TO
UNCERTAINTY IN WIND FORECAST. SCATTERED TO NUMEROUS SHOWERS AND
SOME THUNDERSTORMS EXPECTED.

TUESDAY THROUGH THURSDAY IS WHERE MODELS BEGIN TO DIVERGE. THE NAM
PRODUCES A STRONGER COASTAL TROUGH OF LOW PRESSURE OVER THE
NEARSHORE WATERS THROUGH AT LEAST WEDNESDAY...WHILE THE GLOBAL
MODELS SHOW A MUCH WEAKER COASTAL TROUGH...AND BUILD IN A STRONGER
HIGH PRESSURE FROM THE NORTH...ESPECIALLY WEDNESDAY AND THURSDAY.
 FOR NOW HAVE BLENDED THE MODEL SOLUTIONS AS BEST AS POSSIBLE...AND
KEPT WINDS AND SEAS BELOW ANY HIGHLIGHTS DUE TO UNCERTAINTY.
HOWEVER...MARINE CUSTOMERS SHOULD STAY TUNED TO THE LATEST UPDATES
AS DUE TO FORECAST UNCERTAINTY...BY MID WEEK.

RIP CURRENTS...EXPECT A MODERATE RISK TO CONTINUE INTO MONDAY DUE TO
LONG PERIOD SWELL...SOUTHERLY FLOW AND SOME LINGERING ASTRONOMICAL
INFLUENCES.

STRENGTHENING ONSHORE WINDS AND BUILDING SEAS COULD AGAIN PRODUCE
AN ELEVATED RISK OF RIP CURRENTS LATER THIS WEEK INTO NEXT WEEKEND.

&&

.TIDES/COASTAL FLOODING...
WILL NEED TO CLOSELY MONITOR FOR POSSIBLE SHALLOW COASTAL FLOODING
ALONG THE CHARLESTON COUNTY COAST WITH THE HIGH TIDE TONIGHT...AS
TIDES CONTINUE TO RUN ABOVE PREDICTED LEVELS.

&&

.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...NONE.

&&

$$

NEAR TERM...WMS
SHORT TERM...RFM
LONG TERM...RFM/SPR
AVIATION...ECT/RFM
MARINE...RFM/WMS
TIDES/COASTAL FLOODING...WMS







AREA FORECAST DISCUSSION

NWS COLUMBIA SC

 153 AM EDT SUN APR 28 2013

.SYNOPSIS...
LOW PRESSURE AND A COLD FRONT CONTINUE TO SLOWLY MARCH TOWARD THE
REGION FROM THE SOUTHERN PLAINS AND WILL MOVE THROUGH THE AREA
MONDAY NIGHT. THIS WILL RESULT IN INCREASING SHOWERS THROUGH
MONDAY NIGHT. THE PATTERN WILL REMAIN ACTIVE THROUGH THE WEEK WITH
CHANCES OF SHOWERS AND THUNDERSTORMS EACH DAY.

&&

.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
LATEST RAP MODEL INDICATING WEAK ISENTROPIC LIFT WITH MOISTURE
CONVERGENCE FOCUS ACROSS NORTHERN MIDLANDS/PIEDMONT. UPPER RIDGE
HOLDING ACROSS SOUTHERN MIDLANDS.  USED SREF POP GUIDANCE AND CUT
POPS BACK SIGNIFICANTLY ACROSS THE SOUTH FOR THE NEXT FEW HOURS
WHERE FORCING WEAK.

SHOWERS SHOULD INCREASE LATE AS ISENTROPIC ASCENT IMPROVES OVER
THE AREA. BY DAYBREAK SUNDAY EXPECT LIKELY SHOWERS ALONG AND NORTH
OF I-20 WITH HIGH CHANCE POPS SOUTH OF I-20. WITH EAST WINDS
PUSHING ADDITIONAL MOISTURE INTO THE AREA SHOWER INTENSITY WILL
BEGIN INCREASING BY DAYBREAK WITH MOST LOCATIONS SEEING UP TO ONE
QUARTER OF AN INCH. WITH THE EXTENSIVE CLOUDS TEMPERATURES
OVERNIGHT WILL GENERALLY BE IN THE MIDDLE 50S.

&&

.SHORT TERM /6 AM SUNDAY MORNING THROUGH MONDAY NIGHT/...
SUNDAY AND SUNDAY NIGHT...LOW PRESSURE WILL BE TRACKING FROM THE
CENTRAL MS VALLEY IN THE MORNING TO THE OHIO VALLEY MONDAY NIGHT.
THE COLD FRONT WILL CONTINUE MOVING INTO THE REGION AND WITH
SOUTHEAST WINDS THE CONFIDENCE IN SHOWERS ACROSS THE AREA IS HIGH.
HAVE INCREASED POPS FOR SUNDAY AND SUNDAY NIGHT AS WELL AS
RAINFALL AMOUNTS...WHILE LOWERING TEMPERATURES A COUPLE OF
DEGREES. RAINFALL AMOUNTS WILL BE GREATEST ACROSS THE WESTERN
MIDLANDS...DUE TO PROXIMITY TO THE FRONT...HOWEVER MOST LOCATIONS
WILL SEE BETWEEN ONE HALF AND ONE INCH OF RAINFALL THROUGH MONDAY
DAYBREAK. TEMPERATURES WILL BE IN THE LOWER TO MIDDLE 70S FOR
DAYTIME HIGHS WITH OVERNIGHT LOWS IN THE UPPER 50S TO LOWER 60S.

MONDAY AND MONDAY NIGHT...COLD FRONT WILL PUSH THROUGH THE
FORECAST AREA MONDAY AFTERNOON WITH SHOWERS TAPERING OFF BEHIND
THE FRONT MONDAY EVENING. ALTHOUGH THERE IS LIMITED INSTABILITY
WITH FORCING FROM THE FRONT THERE IS SOME POTENTIAL FOR THUNDER SO
HAVE REMAINED WITH SHOWERS AND ISOLATED THUNDERSTORMS. SKIES WILL
BEGIN TO SLOWLY CLEAR MONDAY NIGHT...HOWEVER WITH GENERAL
SOUTHERLY FLOW EXPECT PARTLY TO MOSTLY CLOUDY SKIES TO PERSIST
THROUGH MONDAY NIGHT. DAYTIME TEMPERATURES WILL BE IN THE LOWER TO
MIDDLE 70S WITH LOWS MONDAY NIGHT IN THE MIDDLE 50S.

&&

.LONG TERM /TUESDAY THROUGH SATURDAY/...
MODELS REMAIN IN GOOD AGREEMENT THROUGH THE LONG TERM WITH SOME
DIFFERENCES IN TIMING APPEARING ON FRIDAY. THE PATTERN WILL REMAIN
ACTIVE THROUGH THE PERIOD WITH AN OMEGA BLOCK DEVELOPING DURING
THE LATTER HALF OF THE WEEK. THIS WILL RESULT IN SLOW PROGRESSION
OF THE SYSTEMS AND A DEEP UPPER LOW EXPECTED TO MOVE INTO THE
CENTRAL PLAINS BY NEXT FRIDAY. AT THE SURFACE WITH A LOW IN THE
MID MS VALLEY AND A HIGH OVER NEW ENGLAND A WEDGE PATTERN WILL
DEVELOP OVER THE FORECAST AREA. WITH CONSISTENCY IN THE MODELS
OVER THE PAST COUPLE OF RUNS HAVE TRENDED THE FORECAST TO THE
WEDGE WITH INCREASING CLOUDS AND LOWERED TEMPERATURES FOR THURSDAY
ONWARD. BLOCKING PATTERN WILL REMAIN IN TACT THROUGH THE END OF
THE LONG TERM KEEPING THE AREA UNDER THE INFLUENCE OF THE WEDGE.
TEMPERATURES THROUGH THE LONG TERM WILL BE NEAR NORMAL ON TUESDAY
THEN COOLER THAN NORMAL FOR WEDNESDAY THROUGH FRIDAY.

&&

.AVIATION /06Z SUNDAY THROUGH FRIDAY/...
VFR CONDITIONS CURRENTLY OBSERVED ACROSS THE CWA
OVERNIGHT...HOWEVER CONDITIONS WILL GRADUALLY DETERIORATE DURING THE
TAF PERIOD. 88D REGIONAL COMPOSITE SHOWS AN AREA OF SHOWERS AND
THUNDERSTORMS ACROSS NRN/CNTRL GA THAT CONTINUE TO MOVE NORTHEAST
TOWARD THE CWA. GUIDANCE ALONG WITH WRF INDICATE THAT PRECIPITATION
WILL REACH THE TAF SITES BETWEEN 12Z AND 14Z. MOISTURE FLUX AND
ISENTROPIC LIFT INCREASE THROUGH THE DAY INTO THE REMAINDER OF THE
TAF PERIOD. GUIDANCE IS IN GOOD AGREEMENT WITH GRADUALLY LOWERING
CEILINGS THROUGH THE DAY AND EVENING HOURS AND EXPECT AT LEAST MVFR
CONDITIONS FROM MIDDAY THROUGH THE REMAINDER OF THE PERIOD. DID NOT
GO QUITE AS LOW AS SOME OF THE GUIDANCE FOR SUNDAY EVENING
INDICATING THE POTENTIAL FOR IFR CONDITIONS. HAVE DECIDED TO
INTRODUCE SHOWERS THIS MORNING BETWEEN 12Z AND 14Z WITH A TEMPO
GROUP...THEN KEPT A MENTION OF SHOWERS WITH GRADUALLY LOWERING
CEILINGS ALONG 4 TO 5 MILES VSBYS TO GIVE MVFR CONDITIONS FOR THE
REMAINDER OF THE TAF PERIOD. EXPECT WINDS TO VEER SOME THROUGH THE
PERIOD FROM E/ESE TO MORE SE THROUGH THE PERIOD. WIND SPEEDS WILL
AVERAGE FROM 4 TO 8 KNOTS.

EXTENDED AVIATION OUTLOOK...RAINFALL AND CEILING/VSBY RESTRICTIONS
EXPECTED SUNDAY NIGHT THROUGH MONDAY NIGHT. RESTRICTIONS ALSO
POSSIBLE IN SHOWERS TUESDAY AND TUESDAY NIGHT.

&&

.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&

$$






AREA FORECAST DISCUSSION

NWS CHICAGO/ROMEOVILLE IL

 1013 PM CDT MON APR 29 2013

.DISCUSSION...

939 PM...EVENING UPDATE...CONVECTIVE TRENDS OVERNIGHT REMAIN
UNCERTAIN. MASSIVE STORM DEVELOPED SOUTHWEST OF DBQ 1-2 HOURS AGO
PRODUCING UP TO TENNIS BALL SIZED HAIL. THIS STORM HAS SINCE
WEAKENED AS IT MOVES INTO SOUTHWEST WI. ADDITIONAL ACTIVITY ALSO
BUBBLING ACROSS CENTRAL IA AND SHORT TERM/HIGH RES GUIDANCE SEEMS
TO FOCUS ON THIS AREA FOR FURTHER DEVELOPMENT LATE THIS EVENING AS
THE LOW LEVEL JET DEVELOPS/INCREASES...WITH THIS ACTIVITY LIFTING
NORTH INTO SOUTH/CENTRAL WI OVERNIGHT. AT THE SAME TIME...DECENT
AGREEMENT FOR ADDITIONAL DEVELOPMENT OVER LAKE MICHIGAN WHICH
DEVELOPS SOUTHEAST INTO NORTHWEST INDIANA IN THE PREDAWN HOURS
TOWARD SUNRISE. WITH EITHER OF THESE SCENARIOS PLAUSIBLE...ITS
POSSIBLE THAT MUCH OF THE CWA COULD REMAIN DRY OVERNIGHT AND INTO
TUESDAY MORNING. BUT ISOLATED ACTIVITY CURRENTLY DEVELOPING
SOUTHEAST OF DBQ WHICH WILL NEED TO BE MONITORED IN THE SHORT
TERM. THUS GIVEN LOW CONFIDENCE...HAVE MAINTAINED LOW CHANCE POPS
FOR AREAS GENERALLY ALONG/NORTH OF THE I-80 CORRIDOR BUT HAVE
INCLUDED SOME TIMING/TRENDS IN THE GRIDS...ALL OF WHICH WILL
LIKELY NEED ADJUSTMENTS THROUGH THE NIGHT. ANY ORGANIZED CELLS
THAT DEVELOP WILL HAVE THE POTENTIAL TO PRODUCE LARGE HAIL. CMS

//PREV DISCUSSION...
323 PM CDT

MAIN FORECAST CONCERNS ARE TRYING TO TIME PERIODS OF PRECIP
POTENTIAL THROUGH MID-WEEK...AND WARM TEMPS DURING THE SAME TIME
PERIOD. BEYOND MID-WEEK...CLOSED UPPER LOW LOOKS TO INFLUENCE LOCAL
WEATHER FOR SEVERAL DAYS WITH COOLER TEMPS AND PERSISTENT THREAT OF
SCATTERED SHRA/TSRA.

NEAR TERM...TONIGHT-WEDNESDAY

SMALL CLUSTER OF ISOLATED SHRA/TSRA CONTINUES TO PROPAGATE EAST
ALONG THE IL/WI BORDER THIS AFTERNOON...ON NOSE OF 25-30 KT LOW
LEVEL JET PER LOCAL VWP AND ASSOCIATED WARM/MOIST ADVECTION. HAS NOT
BEEN MUCH REDEVELOPMENT UPSTREAM OF THIS CLUSTER...THOUGH IT HAS
BEEN QUITE PERSISTENT IN MAINTAINING AT LEAST ONE FAIRLY STRONG TSRA
CORE FOR SEVERAL HOURS. EXPECT THIS WILL CONTINUE TO MOVE EAST
ACROSS BOONE/MCHENRY AND LAKE COUNTIES OVER THE NEXT COUPLE OF HOURS
AND MAY PRODUCE SOME ISOLATED NICKEL-QUARTER SIZED HAIL SOUTH OF THE
WI STATE LINE. LOOKING AT THE BIGGER PICTURE...GOES VAPOR IMAGERY
DEPICTS ONE MID-LEVEL SHORT WAVE MOVING ACROSS WI/NORTHERN GREAT
LAKES REGION THIS AFTERNOON...WITH ANOTHER UPSTREAM ACROSS KS/NEBR.
IT WOULD APPEAR THAT THERE WOULD BE A LULL IN PRECIP DEVELOPMENT
BETWEEN THESE TWO FORCING MECHANISMS THIS EVENING...WITH THE PLAINS
WAVE APPROACHING THE AREA LATE TONIGHT. HOWEVER...SEVERAL HIGH-RES
CONVECTION-ALLOWING MODELS INDICATE POTENTIAL REDEVELOPMENT OF
SHRA/TSRA ACROSS EASTERN IA INTO NORTHERN IL THIS EVENING...WHERE
WEAK LOW LEVEL JET AND MOIST/INSTABILITY AXIS LINGER. MID-AFTERNOON
VISIBLE SATELLITE IMAGERY DOES INDICATE SOME CU ATTEMPTING TO FORM
ACROSS SOUTHEAST IA WITHIN SFC MOIST AXIS...THOUGH IT IS NOT TOO
IMPRESSIVE AT THIS TIME. SPC RAP MESOANALYSIS DATA DOES DEPICT AN
AXIS OF 1000-2000 J/KG MLCAPE ACROSS SE IA...THOUGH ALSO INDICATES
SOME 75-100 J/KG OF CIN. BASED ON PRESENCE OF MOIST/UNSTABLE AXIS
AND HIGH-RES GUIDANCE TRENDS OF REDEVELOPMENT HAVE CHOSEN TO
MAINTAIN CHANCE POPS FOR SHRA/TSRA ACROSS MAINLY AREAS NORTH OF I-80
THROUGH TONIGHT...ESPECIALLY WEST THIS EVENING AND SPREADING FARTHER
EAST LATER TONIGHT. LACK OF STRONGER SHORT WAVE FORCING KEEPS
CONFIDENCE ON THE LOW SIDE THIS EVENING HOWEVER...WITH A LITTLE
HIGHER CONFIDENCE OVERNIGHT AS PLAINS SHORT WAVE APPROACHES AND
PASSES ACROSS THE AREA EARLY TUESDAY MORNING.

ON TUESDAY...ONCE MORNING SHORT WAVE PASSES IT APPEARS FORCING FOR
ORGANIZED PRECIP WILL BE LACKING. COLD FRONT TO OUR WEST IS NOT
EXPECTED TO MAKE PROGRESS EAST AS UPPER FLOW AMPLIFIES IN RESPONSE
TO STRONG MID/UPPER LEVEL JET MOVING INTO THE PAC NW. THIS
AMPLIFICATION INDUCES SURFACE LOW PRESSURE DEVELOPING AND LIFTING
NORTHEAST INTO ONTARIO. THIS ALLOWS STRONGER LOW LEVEL SOUTH FLOW
ACROSS IL/IN...WITH WARMER TEMPS. COMBINATION OF LOW LEVEL THERMAL
PROGS...850 MB DERIVED TEMP CLIMATOLOGY AND MOS NUMBERS SUGGEST
AFTERNOON HIGHS 80-85...PROVIDED MORNING CLOUD COVER MOVES OUT AS
EXPECTED. 850 MB TEMPS JUST A BIT LOWER WEDNESDAY AS UPPER TROUGH
CONTINUES TO AMPLIFY AND SURFACE COLD FRONTAL TROUGH DRIFTS EAST
INTO THE REGION...THOUGH ESPECIALLY EASTERN AREAS WILL LIKELY BE
BACK INTO THE LOWER 80S WHILE CLOUDS/PRECIP CHANCES INCREASE FROM
THE WEST. VARIOUS GUIDANCE SOLUTIONS SHOW SOME MINOR DIFFERENCES
WITH TIMING OF ARRIVAL OF THE FRONT AND ASSOCIATED PRECIP...THOUGH
ALL BASICALLY INCREASE POPS FAIRLY QUICKLY ACROSS THE CWA WEDNESDAY
NIGHT.

LONGER TERM...THURSDAY-MONDAY

MODELS CONTINUE THE TREND OF THE AMPLIFYING UPPER TROUGH BECOMING
CUT OFF FROM THE MAIN JET AND BECOMING A CLOSED LOW OVER THE
MID/LOWER MISSOURI VALLEY...THEN DRIFTING THIS CIRCULATION TO THE
EAST/NORTHEAST THROUGH THE REMAINDER OF THE FORECAST PERIOD. QUITE A
BIT OF SPREAD REMAINS IN ENSEMBLE SOLUTIONS...AS WELL AS THE
OPERATIONAL RUNS OF THE ECMWF/GFS. HAVE MADE LITTLE CHANGE TO GOING
FORECAST IN THE EXTENDED PERIOD AT THIS POINT BASED ON FAIRLY LOW
CONFIDENCE GIVEN MODEL SPREAD...AND THE NOTORIOUSLY PROBLEMATIC JOB
OF FORECASTING CUT-OFF CLOSED LOW DETAILS DAYS 4 AND BEYOND. OVERALL
HAVE MAINTAINED A FORECAST UTILIZING A BLEND OF GUIDANCE FOR TEMPS
AND POPS. WHILE COOLER...LOOKS LIKE 50S/60S FOR HIGHS AND 40S FOR
LOWS DEPENDING ON CLOUD COVER AND SHOWER COVERAGE. POPS ARE LIKELY
OVERDONE A BIT...AND WILL LIKELY BE ABLE TO BETTER DETAIL THEM IN
COMING DAYS AS THE PATH OF THE UPPER LOW BECOMES MORE CLEAR.

RATZER

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 03Z...

* SHRA/TSRA POTENTIAL OVERNIGHT.

* SOUTH WINDS GUSTING 25-30 KT TUESDAY.

MDB

//DISCUSSION...UPDATED 03Z...

CONVECTIVE TRENDS GENERALLY ON TRACK SO FAR THIS EVENING WITH SOME
SPOTTY ACTIVITY OCCURRING ACROSS EXTREME NORTHWEST IL. BASED ON
INTENSIFYING LOW LEVEL JET AND PUSH OF WARMER AIR ALOFT
ISOLD/SCATTERED DEVELOPMENT MAY CONTINUE ACROSS NORTHWEST/NORTH
CENTRAL ILLINOIS THROUGH EARLY TONIGHT...WITH RFD ON THE EASTERN
FRINGE OF THIS POTENTIAL. FORCING WILL SPREAD EASTWARD OVERNIGHT
WITH THE BEST FOCUS LOOKING TO REMAIN JUST TO THE NORTH OF THE
TERMINALS THEN EXTENDING SOUTHWARD TO SOME DEGREE ACROSS LAKE
MICHIGAN LATE. NEEDED TO EITHER REMOVE TSRA MENTION OR ADJUST TO
TEMPO/VCTS/PREVAILING TSRA DUE TO NOT BEING ABLE TO USE THE PROB30
IN THE FIRST 9 HRS SO HAVE OPTED TO GO WITH A 2 HOUR WINDOW OF
VCTS AT ORD/MDW/GYY TO ACCOUNT FOR POSSIBLE SOUTHWARD EXTENSION OF
DEVELOPMENT LATE TONIGHT. PROBABILITY OF OCCURRENCE AT THESE SITES
IS STILL ABOUT 30 PERCENT BUT SEE ENOUGH OF A THREAT FOR SOMETHING
NEARBY TO WARRANT THE MENTION FOR NOW.

MDB

FROM 00Z...

SHRA/TSRA FORECAST REMAINS TRICKY THIS EVENING BUT DO HAVE SOME
INCREASED CONFIDENCE THAT CHANCES ARE PRETTY LOW. WARM AIR
CONTINUES TO STREAM IN ALOFT OVER EASTERN IA/NW IL WITH
INSTABILITY MAXIMIZED ACROSS THAT AREA. SATELLITE DOES SHOW SOME
CU DEVELOPMENT BUT HAVE SEEN NO EVIDENCE OF PRECIP DEVELOPMENT ON
RADAR AS OF 2330Z. IT APPEARS THAT DEVELOPMENT WILL BE SUPPRESSED
OVER THE NEXT FEW HOURS BUT CANNOT RULE OUT SOME SPOTTY
DEVELOPMENT ACROSS FAR NW IL AFTER SUNSET. WILL MAINTAIN THE TEMPO
TSRA AT RFD FOR NOW BUT AM THINKING THIS IS OVERDONE SO MAY NEED
TO ADJUST IN THE NEXT FEW HOURS. WILL RETAIN PROB30 TSRA AT THE
REMAINING SITES FOR NOW AS WELL BUT WILL NEED ADJUST AT 03Z
REGARDLESS. CHANCES STILL LOOK LIMITED BUT THERE MAY BE SOME
DEVELOPMENT ON THE EDGE OF THE ELEVATED INSTABILITY WHICH WILL BE
OVER WESTERN LAKE MICHIGAN LATE TONIGHT AND SLOWLY PUSHING
EASTWARD. THIS MAY RESULT IN GYY HAVING THE BEST CHANCE FOR
SOMETHING TO OCCUR. ANY ACTIVITY WILL LIFT AWAY FROM THE TERMINALS
WITH DRY WEATHER EXPECTED DURING THE DAY TUESDAY THROUGH TUESDAY
EVENING.

SOUTH TO SOUTH-SOUTHEAST WINDS WILL CONTINUE TO GUST 20-25 KT FOR
A FEW HOURS BEFORE GUSTS DIMINISH. WINDS WILL PICK UP AFTER
SUNRISE AS THE PRESSURE GRADIENT TIGHTENS THROUGH MIDDAY TUESDAY
AND GUSTS IN THE 25-30 KT RANGE LOOK LIKELY...ESPECIALLY DURING
THE MID AND LATE AFTERNOON.

MDB

//ORD AND MDW CONFIDENCE...UPDATED 03Z...

* LOW CONFIDENCE IN POTENTIAL FOR SHRA/TSRA OCCURRENCE AT THE
  TERMINALS...MEDIUM CONFIDENCE THAT IT WOULD BE SHORT LIVED.

* HIGH CONFIDENCE IN WIND TRENDS/GUSTS TUESDAY.

MDB

//OUTLOOK FOR ORD/MDW FOR 12Z WEDNESDAY-12Z MONDAY...UPDATED 00Z...

WEDNESDAY...LOW SHRA/TSRA CHANCES INCREASE LATE.

THURSDAY...CHANCE SHRA/TSRA. MVFR POSSIBLE.

FRIDAY...SHRA LIKELY. MVFR LIKELY.

SATURDAY...CHANCE SHRA. MVFR POSSIBLE.

SUNDAY...SLIGHT CHANCE SHRA.

MDB

&&

.MARINE...
205 PM CDT

A POTENT AREA OF LOW PRESSURE IS FORECAST MOVE EASTWARD ACROSS THE
DAKOTAS TONIGHT...AND THEN MOVE NORTHEASTWARD ACROSS ONTARIO ON
TUESDAY. STRONG PRESSURE FALLS AND A STRENGTHENING PRESSURE GRADIENT
SHOULD LEAD TO A PERIOD OF STRONGER SOUTHERLY WINDS ACROSS THE LAKE
ON TUESDAY. IT APPEARS WINDS WILL INCREASE TO AROUND 30 KT
LAKE-WIDE.

THIS LOW WILL EVENTUALLY BEGIN TO PUSH A COLD FRONT DOWN LAKE
MICHIGAN DURING THE DAY ON WEDNESDAY. HOWEVER...CONFIDENCE ON THE
TIMING OF THIS FRONT IS A BIT LOW AT THIS TIME..ESPECIALLY ALONG
THE SOUTHERN HALF OF LAKE MICHIGAN. IT APPEARS THE FRONT  MAY BE
SLOWED BY THE DEVELOPMENT OF ANOTHER AREA OF LOW PRESSURE ACROSS THE
MID MISSISSIPPI VALLEY. THIS WILL ULTIMATELY AFFECT THE WIND
DIRECTIONS ON SOUTHERN LAKE MICHIGAN LATER THIS WEEK. NORTHERLY
WINDS OF 25 TO 30 KT LOOK TO SET UP FOR A PERIOD IN THE WAKE OF THIS
FRONTAL BOUNDARY ON THURSDAY.

KJB

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
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WWW.TWITTER.COM/NWSCHICAGO
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AREA FORECAST DISCUSSION

NWS CHICAGO/ROMEOVILLE IL

 939 PM CDT MON APR 29 2013

.DISCUSSION...

939 PM...EVENING UPDATE...CONVECTIVE TRENDS OVERNIGHT REMAIN
UNCERTAIN. MASSIVE STORM DEVELOPED SOUTHWEST OF DBQ 1-2 HOURS AGO
PRODUCING UP TO TENNIS BALL SIZED HAIL. THIS STORM HAS SINCE
WEAKENED AS IT MOVES INTO SOUTHWEST WI. ADDITIONAL ACTIVITY ALSO
BUBBLING ACROSS CENTRAL IA AND SHORT TERM/HIGH RES GUIDANCE SEEMS
TO FOCUS ON THIS AREA FOR FURTHER DEVELOPMENT LATE THIS EVENING AS
THE LOW LEVEL JET DEVELOPS/INCREASES...WITH THIS ACTIVITY LIFTING
NORTH INTO SOUTH/CENTRAL WI OVERNIGHT. AT THE SAME TIME...DECENT
AGREEMENT FOR ADDITIONAL DEVELOPMENT OVER LAKE MICHIGAN WHICH
DEVELOPS SOUTHEAST INTO NORTHWEST INDIANA IN THE PREDAWN HOURS
TOWARD SUNRISE. WITH EITHER OF THESE SCENARIOS PLAUSIBLE...ITS
POSSIBLE THAT MUCH OF THE CWA COULD REMAIN DRY OVERNIGHT AND INTO
TUESDAY MORNING. BUT ISOLATED ACTIVITY CURRENTLY DEVELOPING
SOUTHEAST OF DBQ WHICH WILL NEED TO BE MONITORED IN THE SHORT
TERM. THUS GIVEN LOW CONFIDENCE...HAVE MAINTAINED LOW CHANCE POPS
FOR AREAS GENERALLY ALONG/NORTH OF THE I-80 CORRIDOR BUT HAVE
INCLUDED SOME TIMING/TRENDS IN THE GRIDS...ALL OF WHICH WILL
LIKELY NEED ADJUSTMENTS THROUGH THE NIGHT. ANY ORGANIZED CELLS
THAT DEVELOP WILL HAVE THE POTENTIAL TO PRODUCE LARGE HAIL. CMS

&&

.PREV DISCUSSION...
323 PM CDT

MAIN FORECAST CONCERNS ARE TRYING TO TIME PERIODS OF PRECIP
POTENTIAL THROUGH MID-WEEK...AND WARM TEMPS DURING THE SAME TIME
PERIOD. BEYOND MID-WEEK...CLOSED UPPER LOW LOOKS TO INFLUENCE LOCAL
WEATHER FOR SEVERAL DAYS WITH COOLER TEMPS AND PERSISTENT THREAT OF
SCATTERED SHRA/TSRA.

NEAR TERM...TONIGHT-WEDNESDAY

SMALL CLUSTER OF ISOLATED SHRA/TSRA CONTINUES TO PROPAGATE EAST
ALONG THE IL/WI BORDER THIS AFTERNOON...ON NOSE OF 25-30 KT LOW
LEVEL JET PER LOCAL VWP AND ASSOCIATED WARM/MOIST ADVECTION. HAS NOT
BEEN MUCH REDEVELOPMENT UPSTREAM OF THIS CLUSTER...THOUGH IT HAS
BEEN QUITE PERSISTENT IN MAINTAINING AT LEAST ONE FAIRLY STRONG TSRA
CORE FOR SEVERAL HOURS. EXPECT THIS WILL CONTINUE TO MOVE EAST
ACROSS BOONE/MCHENRY AND LAKE COUNTIES OVER THE NEXT COUPLE OF HOURS
AND MAY PRODUCE SOME ISOLATED NICKEL-QUARTER SIZED HAIL SOUTH OF THE
WI STATE LINE. LOOKING AT THE BIGGER PICTURE...GOES VAPOR IMAGERY
DEPICTS ONE MID-LEVEL SHORT WAVE MOVING ACROSS WI/NORTHERN GREAT
LAKES REGION THIS AFTERNOON...WITH ANOTHER UPSTREAM ACROSS KS/NEBR.
IT WOULD APPEAR THAT THERE WOULD BE A LULL IN PRECIP DEVELOPMENT
BETWEEN THESE TWO FORCING MECHANISMS THIS EVENING...WITH THE PLAINS
WAVE APPROACHING THE AREA LATE TONIGHT. HOWEVER...SEVERAL HIGH-RES
CONVECTION-ALLOWING MODELS INDICATE POTENTIAL REDEVELOPMENT OF
SHRA/TSRA ACROSS EASTERN IA INTO NORTHERN IL THIS EVENING...WHERE
WEAK LOW LEVEL JET AND MOIST/INSTABILITY AXIS LINGER. MID-AFTERNOON
VISIBLE SATELLITE IMAGERY DOES INDICATE SOME CU ATTEMPTING TO FORM
ACROSS SOUTHEAST IA WITHIN SFC MOIST AXIS...THOUGH IT IS NOT TOO
IMPRESSIVE AT THIS TIME. SPC RAP MESOANALYSIS DATA DOES DEPICT AN
AXIS OF 1000-2000 J/KG MLCAPE ACROSS SE IA...THOUGH ALSO INDICATES
SOME 75-100 J/KG OF CIN. BASED ON PRESENCE OF MOIST/UNSTABLE AXIS
AND HIGH-RES GUIDANCE TRENDS OF REDEVELOPMENT HAVE CHOSEN TO
MAINTAIN CHANCE POPS FOR SHRA/TSRA ACROSS MAINLY AREAS NORTH OF I-80
THROUGH TONIGHT...ESPECIALLY WEST THIS EVENING AND SPREADING FARTHER
EAST LATER TONIGHT. LACK OF STRONGER SHORT WAVE FORCING KEEPS
CONFIDENCE ON THE LOW SIDE THIS EVENING HOWEVER...WITH A LITTLE
HIGHER CONFIDENCE OVERNIGHT AS PLAINS SHORT WAVE APPROACHES AND
PASSES ACROSS THE AREA EARLY TUESDAY MORNING.

ON TUESDAY...ONCE MORNING SHORT WAVE PASSES IT APPEARS FORCING FOR
ORGANIZED PRECIP WILL BE LACKING. COLD FRONT TO OUR WEST IS NOT
EXPECTED TO MAKE PROGRESS EAST AS UPPER FLOW AMPLIFIES IN RESPONSE
TO STRONG MID/UPPER LEVEL JET MOVING INTO THE PAC NW. THIS
AMPLIFICATION INDUCES SURFACE LOW PRESSURE DEVELOPING AND LIFTING
NORTHEAST INTO ONTARIO. THIS ALLOWS STRONGER LOW LEVEL SOUTH FLOW
ACROSS IL/IN...WITH WARMER TEMPS. COMBINATION OF LOW LEVEL THERMAL
PROGS...850 MB DERIVED TEMP CLIMATOLOGY AND MOS NUMBERS SUGGEST
AFTERNOON HIGHS 80-85...PROVIDED MORNING CLOUD COVER MOVES OUT AS
EXPECTED. 850 MB TEMPS JUST A BIT LOWER WEDNESDAY AS UPPER TROUGH
CONTINUES TO AMPLIFY AND SURFACE COLD FRONTAL TROUGH DRIFTS EAST
INTO THE REGION...THOUGH ESPECIALLY EASTERN AREAS WILL LIKELY BE
BACK INTO THE LOWER 80S WHILE CLOUDS/PRECIP CHANCES INCREASE FROM
THE WEST. VARIOUS GUIDANCE SOLUTIONS SHOW SOME MINOR DIFFERENCES
WITH TIMING OF ARRIVAL OF THE FRONT AND ASSOCIATED PRECIP...THOUGH
ALL BASICALLY INCREASE POPS FAIRLY QUICKLY ACROSS THE CWA WEDNESDAY
NIGHT.

LONGER TERM...THURSDAY-MONDAY

MODELS CONTINUE THE TREND OF THE AMPLIFYING UPPER TROUGH BECOMING
CUT OFF FROM THE MAIN JET AND BECOMING A CLOSED LOW OVER THE
MID/LOWER MISSOURI VALLEY...THEN DRIFTING THIS CIRCULATION TO THE
EAST/NORTHEAST THROUGH THE REMAINDER OF THE FORECAST PERIOD. QUITE A
BIT OF SPREAD REMAINS IN ENSEMBLE SOLUTIONS...AS WELL AS THE
OPERATIONAL RUNS OF THE ECMWF/GFS. HAVE MADE LITTLE CHANGE TO GOING
FORECAST IN THE EXTENDED PERIOD AT THIS POINT BASED ON FAIRLY LOW
CONFIDENCE GIVEN MODEL SPREAD...AND THE NOTORIOUSLY PROBLEMATIC JOB
OF FORECASTING CUT-OFF CLOSED LOW DETAILS DAYS 4 AND BEYOND. OVERALL
HAVE MAINTAINED A FORECAST UTILIZING A BLEND OF GUIDANCE FOR TEMPS
AND POPS. WHILE COOLER...LOOKS LIKE 50S/60S FOR HIGHS AND 40S FOR
LOWS DEPENDING ON CLOUD COVER AND SHOWER COVERAGE. POPS ARE LIKELY
OVERDONE A BIT...AND WILL LIKELY BE ABLE TO BETTER DETAIL THEM IN
COMING DAYS AS THE PATH OF THE UPPER LOW BECOMES MORE CLEAR.

RATZER

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 00Z...

* LOW CHANCE SHRA/TSRA LATE THIS EVENING AND OVERNIGHT.

MDB

//DISCUSSION...UPDATED 00Z...

SHRA/TSRA FORECAST REMAINS TRICKY THIS EVENING BUT DO HAVE SOME
INCREASED CONFIDENCE THAT CHANCES ARE PRETTY LOW. WARM AIR
CONTINUES TO STREAM IN ALOFT OVER EASTERN IA/NW IL WITH
INSTABILITY MAXIMIZED ACROSS THAT AREA. SATELLITE DOES SHOW SOME
CU DEVELOPMENT BUT HAVE SEEN NO EVIDENCE OF PRECIP DEVELOPMENT ON
RADAR AS OF 2330Z. IT APPEARS THAT DEVELOPMENT WILL BE SUPPRESSED
OVER THE NEXT FEW HOURS BUT CANNOT RULE OUT SOME SPOTTY
DEVELOPMENT ACROSS FAR NW IL AFTER SUNSET. WILL MAINTAIN THE TEMPO
TSRA AT RFD FOR NOW BUT AM THINKING THIS IS OVERDONE SO MAY NEED
TO ADJUST IN THE NEXT FEW HOURS. WILL RETAIN PROB30 TSRA AT THE
REMAINING SITES FOR NOW AS WELL BUT WILL NEED ADJUST AT 03Z
REGARDLESS. CHANCES STILL LOOK LIMITED BUT THERE MAY BE SOME
DEVELOPMENT ON THE EDGE OF THE ELEVATED INSTABILITY WHICH WILL BE
OVER WESTERN LAKE MICHIGAN LATE TONIGHT AND SLOWLY PUSHING
EASTWARD. THIS MAY RESULT IN GYY HAVING THE BEST CHANCE FOR
SOMETHING TO OCCUR. ANY ACTIVITY WILL LIFT AWAY FROM THE TERMINALS
WITH DRY WEATHER EXPECTED DURING THE DAY TUESDAY THROUGH TUESDAY
EVENING.

SOUTH TO SOUTH-SOUTHEAST WINDS WILL CONTINUE TO GUST 20-25 KT FOR
A FEW HOURS BEFORE GUSTS DIMINISH. WINDS WILL PICK UP AFTER
SUNRISE AS THE PRESSURE GRADIENT TIGHTENS THROUGH MIDDAY TUESDAY
AND GUSTS IN THE 25-30 KT RANGE LOOK LIKELY...ESPECIALLY DURING
THE MID AND LATE AFTERNOON.

MDB

//ORD AND MDW CONFIDENCE...UPDATED 00Z...

* LOW CONFIDENCE IN SHRA/TSRA OCCURRING LATE THIS EVENING OR
  OVERNIGHT.

MDB

//OUTLOOK FOR ORD/MDW FOR 12Z WEDNESDAY-12Z MONDAY...UPDATED 00Z...

WEDNESDAY...LOW SHRA/TSRA CHANCES INCREASE LATE.

THURSDAY...CHANCE SHRA/TSRA. MVFR POSSIBLE.

FRIDAY...SHRA LIKELY. MVFR LIKELY.

SATURDAY...CHANCE SHRA. MVFR POSSIBLE.

SUNDAY...SLIGHT CHANCE SHRA.

MDB

&&

.MARINE...
205 PM CDT

A POTENT AREA OF LOW PRESSURE IS FORECAST MOVE EASTWARD ACROSS THE
DAKOTAS TONIGHT...AND THEN MOVE NORTHEASTWARD ACROSS ONTARIO ON
TUESDAY. STRONG PRESSURE FALLS AND A STRENGTHENING PRESSURE GRADIENT
SHOULD LEAD TO A PERIOD OF STRONGER SOUTHERLY WINDS ACROSS THE LAKE
ON TUESDAY. IT APPEARS WINDS WILL INCREASE TO AROUND 30 KT
LAKE-WIDE.

THIS LOW WILL EVENTUALLY BEGIN TO PUSH A COLD FRONT DOWN LAKE
MICHIGAN DURING THE DAY ON WEDNESDAY. HOWEVER...CONFIDENCE ON THE
TIMING OF THIS FRONT IS A BIT LOW AT THIS TIME..ESPECIALLY ALONG
THE SOUTHERN HALF OF LAKE MICHIGAN. IT APPEARS THE FRONT  MAY BE
SLOWED BY THE DEVELOPMENT OF ANOTHER AREA OF LOW PRESSURE ACROSS THE
MID MISSISSIPPI VALLEY. THIS WILL ULTIMATELY AFFECT THE WIND
DIRECTIONS ON SOUTHERN LAKE MICHIGAN LATER THIS WEEK. NORTHERLY
WINDS OF 25 TO 30 KT LOOK TO SET UP FOR A PERIOD IN THE WAKE OF THIS
FRONTAL BOUNDARY ON THURSDAY.

KJB

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO






AREA FORECAST DISCUSSION

NWS CHICAGO/ROMEOVILLE IL

 642 PM CDT MON APR 29 2013

.DISCUSSION...
323 PM CDT

MAIN FORECAST CONCERNS ARE TRYING TO TIME PERIODS OF PRECIP
POTENTIAL THROUGH MID-WEEK...AND WARM TEMPS DURING THE SAME TIME
PERIOD. BEYOND MID-WEEK...CLOSED UPPER LOW LOOKS TO INFLUENCE LOCAL
WEATHER FOR SEVERAL DAYS WITH COOLER TEMPS AND PERSISTENT THREAT OF
SCATTERED SHRA/TSRA.

NEAR TERM...TONIGHT-WEDNESDAY

SMALL CLUSTER OF ISOLATED SHRA/TSRA CONTINUES TO PROPAGATE EAST
ALONG THE IL/WI BORDER THIS AFTERNOON...ON NOSE OF 25-30 KT LOW
LEVEL JET PER LOCAL VWP AND ASSOCIATED WARM/MOIST ADVECTION. HAS NOT
BEEN MUCH REDEVELOPMENT UPSTREAM OF THIS CLUSTER...THOUGH IT HAS
BEEN QUITE PERSISTENT IN MAINTAINING AT LEAST ONE FAIRLY STRONG TSRA
CORE FOR SEVERAL HOURS. EXPECT THIS WILL CONTINUE TO MOVE EAST
ACROSS BOONE/MCHENRY AND LAKE COUNTIES OVER THE NEXT COUPLE OF HOURS
AND MAY PRODUCE SOME ISOLATED NICKEL-QUARTER SIZED HAIL SOUTH OF THE
WI STATE LINE. LOOKING AT THE BIGGER PICTURE...GOES VAPOR IMAGERY
DEPICTS ONE MID-LEVEL SHORT WAVE MOVING ACROSS WI/NORTHERN GREAT
LAKES REGION THIS AFTERNOON...WITH ANOTHER UPSTREAM ACROSS KS/NEBR.
IT WOULD APPEAR THAT THERE WOULD BE A LULL IN PRECIP DEVELOPMENT
BETWEEN THESE TWO FORCING MECHANISMS THIS EVENING...WITH THE PLAINS
WAVE APPROACHING THE AREA LATE TONIGHT. HOWEVER...SEVERAL HIGH-RES
CONVECTION-ALLOWING MODELS INDICATE POTENTIAL REDEVELOPMENT OF
SHRA/TSRA ACROSS EASTERN IA INTO NORTHERN IL THIS EVENING...WHERE
WEAK LOW LEVEL JET AND MOIST/INSTABILITY AXIS LINGER. MID-AFTERNOON
VISIBLE SATELLITE IMAGERY DOES INDICATE SOME CU ATTEMPTING TO FORM
ACROSS SOUTHEAST IA WITHIN SFC MOIST AXIS...THOUGH IT IS NOT TOO
IMPRESSIVE AT THIS TIME. SPC RAP MESOANALYSIS DATA DOES DEPICT AN
AXIS OF 1000-2000 J/KG MLCAPE ACROSS SE IA...THOUGH ALSO INDICATES
SOME 75-100 J/KG OF CIN. BASED ON PRESENCE OF MOIST/UNSTABLE AXIS
AND HIGH-RES GUIDANCE TRENDS OF REDEVELOPMENT HAVE CHOSEN TO
MAINTAIN CHANCE POPS FOR SHRA/TSRA ACROSS MAINLY AREAS NORTH OF I-80
THROUGH TONIGHT...ESPECIALLY WEST THIS EVENING AND SPREADING FARTHER
EAST LATER TONIGHT. LACK OF STRONGER SHORT WAVE FORCING KEEPS
CONFIDENCE ON THE LOW SIDE THIS EVENING HOWEVER...WITH A LITTLE
HIGHER CONFIDENCE OVERNIGHT AS PLAINS SHORT WAVE APPROACHES AND
PASSES ACROSS THE AREA EARLY TUESDAY MORNING.

ON TUESDAY...ONCE MORNING SHORT WAVE PASSES IT APPEARS FORCING FOR
ORGANIZED PRECIP WILL BE LACKING. COLD FRONT TO OUR WEST IS NOT
EXPECTED TO MAKE PROGRESS EAST AS UPPER FLOW AMPLIFIES IN RESPONSE
TO STRONG MID/UPPER LEVEL JET MOVING INTO THE PAC NW. THIS
AMPLIFICATION INDUCES SURFACE LOW PRESSURE DEVELOPING AND LIFTING
NORTHEAST INTO ONTARIO. THIS ALLOWS STRONGER LOW LEVEL SOUTH FLOW
ACROSS IL/IN...WITH WARMER TEMPS. COMBINATION OF LOW LEVEL THERMAL
PROGS...850 MB DERIVED TEMP CLIMATOLOGY AND MOS NUMBERS SUGGEST
AFTERNOON HIGHS 80-85...PROVIDED MORNING CLOUD COVER MOVES OUT AS
EXPECTED. 850 MB TEMPS JUST A BIT LOWER WEDNESDAY AS UPPER TROUGH
CONTINUES TO AMPLIFY AND SURFACE COLD FRONTAL TROUGH DRIFTS EAST
INTO THE REGION...THOUGH ESPECIALLY EASTERN AREAS WILL LIKELY BE
BACK INTO THE LOWER 80S WHILE CLOUDS/PRECIP CHANCES INCREASE FROM
THE WEST. VARIOUS GUIDANCE SOLUTIONS SHOW SOME MINOR DIFFERENCES
WITH TIMING OF ARRIVAL OF THE FRONT AND ASSOCIATED PRECIP...THOUGH
ALL BASICALLY INCREASE POPS FAIRLY QUICKLY ACROSS THE CWA WEDNESDAY
NIGHT.

LONGER TERM...THURSDAY-MONDAY

MODELS CONTINUE THE TREND OF THE AMPLIFYING UPPER TROUGH BECOMING
CUT OFF FROM THE MAIN JET AND BECOMING A CLOSED LOW OVER THE
MID/LOWER MISSOURI VALLEY...THEN DRIFTING THIS CIRCULATION TO THE
EAST/NORTHEAST THROUGH THE REMAINDER OF THE FORECAST PERIOD. QUITE A
BIT OF SPREAD REMAINS IN ENSEMBLE SOLUTIONS...AS WELL AS THE
OPERATIONAL RUNS OF THE ECMWF/GFS. HAVE MADE LITTLE CHANGE TO GOING
FORECAST IN THE EXTENDED PERIOD AT THIS POINT BASED ON FAIRLY LOW
CONFIDENCE GIVEN MODEL SPREAD...AND THE NOTORIOUSLY PROBLEMATIC JOB
OF FORECASTING CUT-OFF CLOSED LOW DETAILS DAYS 4 AND BEYOND. OVERALL
HAVE MAINTAINED A FORECAST UTILIZING A BLEND OF GUIDANCE FOR TEMPS
AND POPS. WHILE COOLER...LOOKS LIKE 50S/60S FOR HIGHS AND 40S FOR
LOWS DEPENDING ON CLOUD COVER AND SHOWER COVERAGE. POPS ARE LIKELY
OVERDONE A BIT...AND WILL LIKELY BE ABLE TO BETTER DETAIL THEM IN
COMING DAYS AS THE PATH OF THE UPPER LOW BECOMES MORE CLEAR.

RATZER

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 00Z...

* LOW CHANCE SHRA/TSRA LATE THIS EVENING AND OVERNIGHT.

MDB

//DISCUSSION...UPDATED 00Z...

SHRA/TSRA FORECAST REMAINS TRICKY THIS EVENING BUT DO HAVE SOME
INCREASED CONFIDENCE THAT CHANCES ARE PRETTY LOW. WARM AIR
CONTINUES TO STREAM IN ALOFT OVER EASTERN IA/NW IL WITH
INSTABILITY MAXIMIZED ACROSS THAT AREA. SATELLITE DOES SHOW SOME
CU DEVELOPMENT BUT HAVE SEEN NO EVIDENCE OF PRECIP DEVELOPMENT ON
RADAR AS OF 2330Z. IT APPEARS THAT DEVELOPMENT WILL BE SUPPRESSED
OVER THE NEXT FEW HOURS BUT CANNOT RULE OUT SOME SPOTTY
DEVELOPMENT ACROSS FAR NW IL AFTER SUNSET. WILL MAINTAIN THE TEMPO
TSRA AT RFD FOR NOW BUT AM THINKING THIS IS OVERDONE SO MAY NEED
TO ADJUST IN THE NEXT FEW HOURS. WILL RETAIN PROB30 TSRA AT THE
REMAINING SITES FOR NOW AS WELL BUT WILL NEED ADJUST AT 03Z
REGARDLESS. CHANCES STILL LOOK LIMITED BUT THERE MAY BE SOME
DEVELOPMENT ON THE EDGE OF THE ELEVATED INSTABILITY WHICH WILL BE
OVER WESTERN LAKE MICHIGAN LATE TONIGHT AND SLOWLY PUSHING
EASTWARD. THIS MAY RESULT IN GYY HAVING THE BEST CHANCE FOR
SOMETHING TO OCCUR. ANY ACTIVITY WILL LIFT AWAY FROM THE TERMINALS
WITH DRY WEATHER EXPECTED DURING THE DAY TUESDAY THROUGH TUESDAY
EVENING.

SOUTH TO SOUTH-SOUTHEAST WINDS WILL CONTINUE TO GUST 20-25 KT FOR
A FEW HOURS BEFORE GUSTS DIMINISH. WINDS WILL PICK UP AFTER
SUNRISE AS THE PRESSURE GRADIENT TIGHTENS THROUGH MIDDAY TUESDAY
AND GUSTS IN THE 25-30 KT RANGE LOOK LIKELY...ESPECIALLY DURING
THE MID AND LATE AFTERNOON.

MDB


//ORD AND MDW CONFIDENCE...UPDATED 00Z...

* LOW CONFIDENCE IN SHRA/TSRA OCCURRING LATE THIS EVENING OR
  OVERNIGHT.

MDB

//OUTLOOK FOR ORD/MDW FOR 12Z WEDNESDAY-12Z MONDAY...UPDATED 00Z...

WEDNESDAY...LOW SHRA/TSRA CHANCES INCREASE LATE.

THURSDAY...CHANCE SHRA/TSRA. MVFR POSSIBLE.

FRIDAY...SHRA LIKELY. MVFR LIKELY.

SATURDAY...CHANCE SHRA. MVFR POSSIBLE.

SUNDAY...SLIGHT CHANCE SHRA.

MDB

&&

.MARINE...
205 PM CDT

A POTENT AREA OF LOW PRESSURE IS FORECAST MOVE EASTWARD ACROSS THE
DAKOTAS TONIGHT...AND THEN MOVE NORTHEASTWARD ACROSS ONTARIO ON
TUESDAY. STRONG PRESSURE FALLS AND A STRENGTHENING PRESSURE GRADIENT
SHOULD LEAD TO A PERIOD OF STRONGER SOUTHERLY WINDS ACROSS THE LAKE
ON TUESDAY. IT APPEARS WINDS WILL INCREASE TO AROUND 30 KT
LAKE-WIDE.

THIS LOW WILL EVENTUALLY BEGIN TO PUSH A COLD FRONT DOWN LAKE
MICHIGAN DURING THE DAY ON WEDNESDAY. HOWEVER...CONFIDENCE ON THE
TIMING OF THIS FRONT IS A BIT LOW AT THIS TIME..ESPECIALLY ALONG
THE SOUTHERN HALF OF LAKE MICHIGAN. IT APPEARS THE FRONT  MAY BE
SLOWED BY THE DEVELOPMENT OF ANOTHER AREA OF LOW PRESSURE ACROSS THE
MID MISSISSIPPI VALLEY. THIS WILL ULTIMATELY AFFECT THE WIND
DIRECTIONS ON SOUTHERN LAKE MICHIGAN LATER THIS WEEK. NORTHERLY
WINDS OF 25 TO 30 KT LOOK TO SET UP FOR A PERIOD IN THE WAKE OF THIS
FRONTAL BOUNDARY ON THURSDAY.

KJB

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO






AREA FORECAST DISCUSSION

NWS LINCOLN IL

 105 PM CDT SUN APR 28 2013

.DISCUSSION...
ISSUED 1038 AM CDT SUN APR 28 2013
LOW CENTER IN EAST CENTRAL INDIANA THIS MORNING...WITH LOW
STRATUS...DRIZZLE...AND COOL TEMPERATURES DOMINATING CENTRAL
ILLINOIS. WESTERN EDGE OF THE LOWEST CEILINGS ERODING SLOWLY ON
VIS AND IR SAT IMAGERY. MISS RIVER VALLEY NORTH OF QUINCY UNDER
MOSTLY SUNNY SKIES. WATCHING SUNNY SKIES BUILD SLOWLY
EASTWARD...NW OF THE ILLINOIS RIVER VALLEY LIKELY TO SEE SOME SUN
AND MAX TEMPS IN UPPER 60S/NEAR 70 AS A RESULT. FURTHER TO THE
EAST CLOSER TO THE LOW...A BIT MORE PROBLEMATIC. NOT ANTICIPATING
A SIGNIF LOSS OF CLOUD COVER...AND KEEPING COOLER TEMPS IN AS A
RESULT. SOME MINOR ADJUSTMENTS TO THE FORECAST AND THE HOURLY
GRIDS...THOUGH REISSUANCE NOT ANTICIPATED UNTIL MAYBE AFTER NOON
TO CLEAN UP SOME MORNING WORDING.



&&

.AVIATION...
ISSUED 1254 PM CDT SUN APR 28 2013
SFC LOW NOT MAKING MUCH FORWARD PROGRESS...LEAVING IFR/LIFR
CONDITIONS IN MUCH OF CENTRAL IL. BACK EDGE OF STRATUS DISCERNIBLE
ON VIS/IR SAT IMAGERY. MVFR CONDITIONS CREEPING IN TO SPI AND PIA
AT TAF ISSUANCE...AND SHOULD CONTINUE TO SEE AN IMPROVEMENT OF
CONDITIONS THROUGH THE AFTERNOON...THOUGH OTHER TERMINALS WILL
STRUGGLE FOR IMPROVEMENT LATE BEFORE SUNSET. BIG QUESTION WILL BE
HOW DENSE THE FG/BR OVERNIGHT. WITH PIA SEEING CLEARING
ALREADY...AND THROUGH THE NIGHT...GOOD CHANCE FOR A VIS DROP
THERE. SPI STILL TRYING TO BREAK OUT BUT SURROUNDED BY SOME
LINGERING STRATUS...WILL DEPEND ON HOW MUCH CLEARS OUT THIS
EVENING...AND SAME MENTALITY APPLIES TO OTHER LOCATIONS...THOUGH
CMI AND BMI MAY BE CLOSE ENOUGH TO THE LOW STILL TO KEEP DEGRADED
CONDITIONS IN PLACE. PIA AND SPI MVFR/VFR THROUGH AFTERNOON...DEC
AND BMI IFR...AND CMI WILL LIKELY SEE A BIT OF A DROP IN ITS
VARIABLE CONDITIONS AS LOWER CLOUDS MOVE IN.


HJS
&&

.PREV DISCUSSION...
ISSUED 259 AM CDT SUN APR 28 2013

FORECAST PROBLEMS THIS MORNING IS THE LINGERING PCPN FOR THIS
MORNING...POSSIBLE CLOUD COVER/CLEARING AND FOG SUNDAY NIGHT...AND
THEN THE CLOSING OFF OF AN UPPER LOW MIDWEEK AND ASSOCIATED PCPN.

SHORT TERM...TODAY THROUGH TUESDAY NIGHT...
UPPER AIR DATA...IR SATELLITE...AND THE RADAR LOOP SHOWS EASTERN
MO LOW CENTER AT 00Z...HAD DRIFTED TO THE EAST TO THE AREA AROUND
STL. 00Z UPPER AIR SHOWS DEEP LOW LEVEL MOISTURE AXIS UP THE MS
VALLEY AREA AHEAD OF UPPER FEATURE. WITH 300MB JET SOUTH OF UPPER
LOW...SYSTEM SHOULD CONTINUE TO TRACK EAST...WITH THE FETCH OF
MOISTURE NOW TO THE EAST INTO OH VALLEY REGION. RAP AROUND
MOISTURE/SHOWERS STILL EXPECTED TO GRADUALLY TRANSLATE TO THE EAST
WITH LOW TODAY...WITH SOME CLOUD BREAKUP POSSIBLE IN THE EXTREME
WESTERN PARTS OF CWA. MODIFIED POPS FOR TODAY WITH A GRADUAL SHIFT
TO THE EAST TODAY OF THE LOW. LOWERED HIGHS FOR TODAY OVER ALL BUT
NORTHWEST TO GO WITH EXTENSIVE CLOUD COVER OVER ALL BUT WHERE SOME
CLEARING MAY BE IN NORTHWEST. DUE TO CLEARING TONIGHT...REGION
EAST OF IL RIVER WILL HAVE POSSIBLE FOG DEVELOPMENT OVERNIGHT DUE
TO PLENTY OF OVERNIGHT RAIN AND CLOUD COVER TODAY NOT ALLOWING MIX
OUT OF LOW LEVEL MOISTURE.

A WEAK FRONT APPROACHES THE REGION MONDAY NIGHT...BRINGING A CHANCE
OF PCPN TO THE NORTHWEST SECTIONS. THE FRONT THEN WASHES OUT AND WE
REMAIN DRY IN THE WARM SECTOR TIL WED.

LONG TERM...WEDNESDAY THROUGH SUNDAY...
AN UNSETTLED PERIOD STARTS MIDWEEK AND LASTS TO WEEKEND. AN UPPER
WAVE MOVING THROUGH THE GREAT LAKES TUESDAY NIGHT DRAGS A FRONT
INTO THE MO TO NORTHERN IL REGION. THEN A MAJOR UPPER TROUGH IS
PROGGED TO DIG INTO THE WESTERN PLAINS...CLOSING OFF IN THE
SOUTHERN PLAINS. THE FRONTAL SYSTEM STALLS IN THE MID MS RIVER
VALLEY FROM WED NIGHT INTO THE WEEKEND WITH SCATTERED PCPN ALONG
THE SYSTEM. MODELS HAVE BECOME A LITTLE MORE CONSISTENT AND IN
AGREEMENT WITH THIS SCENARIO...WITH AN UPPER LOW THEN CLOSING OFF
INTO THE PLAINS AND PCPN IN THE MS VALLEY. BY THE WEEKEND...THE
SYSTEM STARTS TO MOVE OUT...HOWEVER THE TIMING ON THIS WILL STILL
NEED TO BE WATCHED. TEMPS DUE TO CLOUDS AND SCT PCPN THROUGHOUT
END OF WEEK IS COOLER THEN THE BEGINNING OF THE WEEK. WENT WITH
CHC POPS AS DETAILS ON THE EXACT POSITION OF THE FRONT AND UPPER
SYSTEM STILL A LITTLE UNCERTAIN.

GOETSCH


&&

.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$








AREA FORECAST DISCUSSION

NWS LINCOLN IL

 1040 AM CDT SUN APR 28 2013

.DISCUSSION...
ISSUED 1038 AM CDT SUN APR 28 2013
LOW CENTER IN EAST CENTRAL INDIANA THIS MORNING...WITH LOW
STRATUS...DRIZZLE...AND COOL TEMPERATURES DOMINATING CENTRAL
ILLINOIS. WESTERN EDGE OF THE LOWEST CEILINGS ERODING SLOWLY ON
VIS AND IR SAT IMAGERY. MISS RIVER VALLEY NORTH OF QUINCY UNDER
MOSTLY SUNNY SKIES. WATCHING SUNNY SKIES BUILD SLOWLY
EASTWARD...NW OF THE ILLINOIS RIVER VALLEY LIKELY TO SEE SOME SUN
AND MAX TEMPS IN UPPER 60S/NEAR 70 AS A RESULT. FURTHER TO THE
EAST CLOSER TO THE LOW...A BIT MORE PROBLEMATIC. NOT ANTICIPATING
A SIGNIF LOSS OF CLOUD COVER...AND KEEPING COOLER TEMPS IN AS A
RESULT. SOME MINOR ADJUSTMENTS TO THE FORECAST AND THE HOURLY
GRIDS...THOUGH REISSUANCE NOT ANTICIPATED UNTIL MAYBE AFTER NOON
TO CLEAN UP SOME MORNING WORDING.


HJS
&&

.AVIATION...
ISSUED 618 AM CDT SUN APR 28 2013

LIFR CONDITIONS WILL LINGER EARLY THIS MORNING...BEFORE CEILINGS
SLOWLY BEGIN TO IMPROVE. NAM FORECAST SOUNDINGS SUGGEST CLOUD BASES
WILL RISE ABOVE 500FT BY 14/15Z...THEN INTO THE MVFR CATEGORY
AROUND 1500FT TOWARD MIDDAY. AS LOW PRESSURE RESPONSIBLE FOR THE
CLOUDS/SHOWERS PULLS FURTHER AWAY...SKIES WILL GRADUALLY CLEAR
FROM WEST TO EAST ACROSS THE AREA LATE THIS AFTERNOON INTO THE
EVENING. NAM/GFS RH PROFILES INDICATE CEILING SCATTERING AT KPIA
BY 22Z...THEN FURTHER EAST TO KCMI BY AROUND 01Z. WITH MOSTLY
CLEAR SKIES AND LIGHT WINDS EXPECTED OVERNIGHT...BIG QUESTION WILL
BE HOW MUCH FOG DEVELOPS. NUMERIC GUIDANCE DOES NOT REDUCE VISBYS
APPRECIABLY...HOWEVER GIVEN AMPLE LOW-LEVEL MOISTURE DUE TO THE
RECENT RAINFALL AND THE FACT THAT MUCH OF THE AREA WILL NOT CLEAR
TODAY...THINK FOG WILL BE A GOOD BET. HAVE HIT VISBYS HARDEST
EAST OF THE ILLINOIS RIVER...WHERE 2 TO 3SM WILL BE COMMON.
FURTHER WEST AT KPIA...DRIER LOW-LEVEL PROFILE WILL YIELD LESSER
RESTRICTIONS DOWN TO AROUND 5SM.

BARNES
&&

.PREV DISCUSSION...
ISSUED 259 AM CDT SUN APR 28 2013

FORECAST PROBLEMS THIS MORNING IS THE LINGERING PCPN FOR THIS
MORNING...POSSIBLE CLOUD COVER/CLEARING AND FOG SUNDAY NIGHT...AND
THEN THE CLOSING OFF OF AN UPPER LOW MIDWEEK AND ASSOCIATED PCPN.

SHORT TERM...TODAY THROUGH TUESDAY NIGHT...
UPPER AIR DATA...IR SATELLITE...AND THE RADAR LOOP SHOWS EASTERN
MO LOW CENTER AT 00Z...HAD DRIFTED TO THE EAST TO THE AREA AROUND
STL. 00Z UPPER AIR SHOWS DEEP LOW LEVEL MOISTURE AXIS UP THE MS
VALLEY AREA AHEAD OF UPPER FEATURE. WITH 300MB JET SOUTH OF UPPER
LOW...SYSTEM SHOULD CONTINUE TO TRACK EAST...WITH THE FETCH OF
MOISTURE NOW TO THE EAST INTO OH VALLEY REGION. RAP AROUND
MOISTURE/SHOWERS STILL EXPECTED TO GRADUALLY TRANSLATE TO THE EAST
WITH LOW TODAY...WITH SOME CLOUD BREAKUP POSSIBLE IN THE EXTREME
WESTERN PARTS OF CWA. MODIFIED POPS FOR TODAY WITH A GRADUAL SHIFT
TO THE EAST TODAY OF THE LOW. LOWERED HIGHS FOR TODAY OVER ALL BUT
NORTHWEST TO GO WITH EXTENSIVE CLOUD COVER OVER ALL BUT WHERE SOME
CLEARING MAY BE IN NORTHWEST. DUE TO CLEARING TONIGHT...REGION
EAST OF IL RIVER WILL HAVE POSSIBLE FOG DEVELOPMENT OVERNIGHT DUE
TO PLENTY OF OVERNIGHT RAIN AND CLOUD COVER TODAY NOT ALLOWING MIX
OUT OF LOW LEVEL MOISTURE.

A WEAK FRONT APPROACHES THE REGION MONDAY NIGHT...BRINGING A CHANCE
OF PCPN TO THE NORTHWEST SECTIONS. THE FRONT THEN WASHES OUT AND WE
REMAIN DRY IN THE WARM SECTOR TIL WED.

LONG TERM...WEDNESDAY THROUGH SUNDAY...
AN UNSETTLED PERIOD STARTS MIDWEEK AND LASTS TO WEEKEND. AN UPPER
WAVE MOVING THROUGH THE GREAT LAKES TUESDAY NIGHT DRAGS A FRONT
INTO THE MO TO NORTHERN IL REGION. THEN A MAJOR UPPER TROUGH IS
PROGGED TO DIG INTO THE WESTERN PLAINS...CLOSING OFF IN THE
SOUTHERN PLAINS. THE FRONTAL SYSTEM STALLS IN THE MID MS RIVER
VALLEY FROM WED NIGHT INTO THE WEEKEND WITH SCATTERED PCPN ALONG
THE SYSTEM. MODELS HAVE BECOME A LITTLE MORE CONSISTENT AND IN
AGREEMENT WITH THIS SCENARIO...WITH AN UPPER LOW THEN CLOSING OFF
INTO THE PLAINS AND PCPN IN THE MS VALLEY. BY THE WEEKEND...THE
SYSTEM STARTS TO MOVE OUT...HOWEVER THE TIMING ON THIS WILL STILL
NEED TO BE WATCHED. TEMPS DUE TO CLOUDS AND SCT PCPN THROUGHOUT
END OF WEEK IS COOLER THEN THE BEGINNING OF THE WEEK. WENT WITH
CHC POPS AS DETAILS ON THE EXACT POSITION OF THE FRONT AND UPPER
SYSTEM STILL A LITTLE UNCERTAIN.

GOETSCH


&&

.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$








AREA FORECAST DISCUSSION

NWS LINCOLN IL

 618 AM CDT SUN APR 28 2013

.DISCUSSION...
ISSUED 259 AM CDT SUN APR 28 2013

FORECAST PROBLEMS THIS MORNING IS THE LINGERING PCPN FOR THIS
MORNING...POSSIBLE CLOUD COVER/CLEARING AND FOG SUNDAY NIGHT...AND
THEN THE CLOSING OFF OF AN UPPER LOW MIDWEEK AND ASSOCIATED PCPN.

.SHORT TERM...TODAY THROUGH TUESDAY NIGHT.
UPPER AIR DATA...IR SATELLITE...AND THE RADAR LOOP SHOWS EASTERN MO
LOW CENTER AT 00Z...HAD DRIFTED TO THE EAST TO THE AREA AROUND STL.
00Z UPPER AIR SHOWS DEEP LOW LEVEL MOISTURE AXIS UP THE MS VALLEY
AREA AHEAD OF UPPER FEATURE. WITH 300MB JET SOUTH OF UPPER
LOW...SYSTEM SHOULD CONTINUE TO TRACK EAST...WITH THE FETCH OF
MOISTURE NOW TO THE EAST INTO OH VALLEY REGION. RAP AROUND
MOISTURE/SHOWERS STILL EXPECTED TO GRADUALLY TRANSLATE TO THE EAST
WITH LOW TODAY...WITH SOME CLOUD BREAKUP POSSIBLE IN THE EXTREME
WESTERN PARTS OF CWA. MODIFIED POPS FOR TODAY WITH A GRADUAL SHIFT
TO THE EAST TODAY OF THE LOW. LOWERED HIGHS FOR TODAY OVER ALL BUT
NORTHWEST TO GO WITH EXTENSIVE CLOUD COVER OVER ALL BUT WHERE SOME
CLEARING MAY BE IN NORTHWEST. DUE TO CLEARING TONIGHT...REGION EAST
OF IL RIVER WILL HAVE POSSIBLE FOG DEVELOPMENT OVERNIGHT DUE TO
PLENTY OF OVERNIGHT RAIN AND CLOUD COVER TODAY NOT ALLOWING MIX OUT
OF LOW LEVEL MOISTURE.

A WEAK FRONT APPROACHES THE REGION MONDAY NIGHT...BRINGING A CHANCE
OF PCPN TO THE NORTHWEST SECTIONS. THE FRONT THEN WASHES OUT AND WE
REMAIN DRY IN THE WARM SECTOR TIL WED.

.LONG TERM...WEDNESDAY THROUGH SUNDAY.
AN UNSETTLED PERIOD STARTS MIDWEEK AND LASTS TO WEEKEND. AN UPPER WAVE
MOVING THROUGH THE GREATLAKES TUESDAY NIGHT DRAGS A FRONT INTO THE
MO TO NORTHERN IL REGION. THEN A MAJOR UPPER TROUGH IS PROGGED TO
DIG INTO THE WESTERN PLAINS...CLOSING OFF IN THE SOUTHERN PLAINS.
THE FRONTAL SYSTEM STALLS IN THE MID MS RIVER VALLEY FROM WED NIGHT
INTO THE WEEKEND WITH SCATTERED PCPN ALONG THE SYSTEM. MODELS HAVE
BECOME A LITTLE MORE CONSISTENT AND IN AGREEMENT WITH THIS
SCENARIO...WITH AN UPPER LOW THEN CLOSING OFF INTO THE PLAINS AND
PCPN IN THE MS VALLEY. BY THE WEEKEND...THE SYSTEM STARTS TO MOVE
OUT...HOWEVER THE TIMING ON THIS WILL STILL NEED TO BE WATCHED.
TEMPS DUE TO CLOUDS AND SCT PCPN THROUGHOUT END OF WEEK IS COOLER
THEN THE BEGINNING OF THE WEEK. WENT WITH CHC POPS AS DETAILS ON THE
EXACT POSITION OF THE FRONT AND UPPER SYSTEM STILL A LITTLE
UNCERTAIN.

GOETSCH


&&

.AVIATION...
ISSUED 618 AM CDT SUN APR 28 2013

LIFR CONDITIONS WILL LINGER EARLY THIS MORNING...BEFORE CEILINGS
SLOWLY BEGIN TO IMPROVE. NAM FORECAST SOUNDINGS SUGGEST CLOUD BASES
WILL RISE ABOVE 500FT BY 14/15Z...THEN INTO THE MVFR CATEGORY
AROUND 1500FT TOWARD MIDDAY. AS LOW PRESSURE RESPONSIBLE FOR THE
CLOUDS/SHOWERS PULLS FURTHER AWAY...SKIES WILL GRADUALLY CLEAR
FROM WEST TO EAST ACROSS THE AREA LATE THIS AFTERNOON INTO THE
EVENING. NAM/GFS RH PROFILES INDICATE CEILING SCATTERING AT KPIA
BY 22Z...THEN FURTHER EAST TO KCMI BY AROUND 01Z. WITH MOSTLY
CLEAR SKIES AND LIGHT WINDS EXPECTED OVERNIGHT...BIG QUESTION WILL
BE HOW MUCH FOG DEVELOPS. NUMERIC GUIDANCE DOES NOT REDUCE VISBYS
APPRECIABLY...HOWEVER GIVEN AMPLE LOW-LEVEL MOISTURE DUE TO THE
RECENT RAINFALL AND THE FACT THAT MUCH OF THE AREA WILL NOT CLEAR
TODAY...THINK FOG WILL BE A GOOD BET. HAVE HIT VISBYS HARDEST
EAST OF THE ILLINOIS RIVER...WHERE 2 TO 3SM WILL BE COMMON.
FURTHER WEST AT KPIA...DRIER LOW-LEVEL PROFILE WILL YIELD LESSER
RESTRICTIONS DOWN TO AROUND 5SM.

BARNES
&&

.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$








AREA FORECAST DISCUSSION

NWS LINCOLN IL

 300 AM CDT SUN APR 28 2013

.DISCUSSION...
ISSUED 259 AM CDT SUN APR 28 2013

FORECAST PROBLEMS THIS MORNING IS THE LINGERING PCPN FOR THIS
MORNING...POSSIBLE CLOUD COVER/CLEARING AND FOG SUNDAY NIGHT...AND
THEN THE CLOSING OFF OF AN UPPER LOW MIDWEEK AND ASSOCIATED PCPN.

.SHORT TERM...TODAY THROUGH TUESDAY NIGHT.
UPPER AIR DATA...IR SATELLITE...AND THE RADAR LOOP SHOWS EASTERN MO
LOW CENTER AT 00Z...HAD DRIFTED TO THE EAST TO THE AREA AROUND STL.
00Z UPPER AIR SHOWS DEEP LOW LEVEL MOISTURE AXIS UP THE MS VALLEY
AREA AHEAD OF UPPER FEATURE. WITH 300MB JET SOUTH OF UPPER
LOW...SYSTEM SHOULD CONTINUE TO TRACK EAST...WITH THE FETCH OF
MOISTURE NOW TO THE EAST INTO OH VALLEY REGION. RAP AROUND
MOISTURE/SHOWERS STILL EXPECTED TO GRADUALLY TRANSLATE TO THE EAST
WITH LOW TODAY...WITH SOME CLOUD BREAKUP POSSIBLE IN THE EXTREME
WESTERN PARTS OF CWA. MODIFIED POPS FOR TODAY WITH A GRADUAL SHIFT
TO THE EAST TODAY OF THE LOW. LOWERED HIGHS FOR TODAY OVER ALL BUT
NORTHWEST TO GO WITH EXTENSIVE CLOUD COVER OVER ALL BUT WHERE SOME
CLEARING MAY BE IN NORTHWEST. DUE TO CLEARING TONIGHT...REGION EAST
OF IL RIVER WILL HAVE POSSIBLE FOG DEVELOPMENT OVERNIGHT DUE TO
PLENTY OF OVERNIGHT RAIN AND CLOUD COVER TODAY NOT ALLOWING MIX OUT
OF LOW LEVEL MOISTURE.

A WEAK FRONT APPROACHES THE REGION MONDAY NIGHT...BRINGING A CHANCE
OF PCPN TO THE NORTHWEST SECTIONS. THE FRONT THEN WASHES OUT AND WE
REMAIN DRY IN THE WARM SECTOR TIL WED.

.LONG TERM...WEDNESDAY THROUGH SUNDAY.
AN UNSETTLED PERIOD STARTS MIDWEEK AND LASTS TO WEEKEND. AN UPPER WAVE
MOVING THROUGH THE GREATLAKES TUESDAY NIGHT DRAGS A FRONT INTO THE
MO TO NORTHERN IL REGION. THEN A MAJOR UPPER TROUGH IS PROGGED TO
DIG INTO THE WESTERN PLAINS...CLOSING OFF IN THE SOUTHERN PLAINS.
THE FRONTAL SYSTEM STALLS IN THE MID MS RIVER VALLEY FROM WED NIGHT
INTO THE WEEKEND WITH SCATTERED PCPN ALONG THE SYSTEM. MODELS HAVE
BECOME A LITTLE MORE CONSISTANT AND IN AGREEMENT WITH THIS
SCENARIO...WITH AN UPPER LOW THEN CLOSING OFF INTO THE PLAINS AND
PCPN IN THE MS VALLEY. BY THE WEEKEND...THE SYSTEM STARTS TO MOVE
OUT...HOWEVER THE TIMING ON THIS WILL STILL NEED TO BE WATCHED.
TEMPS DUE TO CLOUDS AND SCT PCPN THROUGHOUT END OF WEEK IS COOLER
THEN THE BEGINNING OF THE WEEK. WENT WITH CHC POPS AS DETAILS ON THE
EXACT POSITION OF THE FRONT AND UPPER SYSTEM STILL A LITTLE
UNCERTAIN.

GOETSCH
&&

.AVIATION...
ISSUED 1148 PM CDT SAT APR 27 2013

A COMPLEX...SLOW MOVING...UPPER LEVEL DISTURBANCE...AND ITS
ASSOCIATED SURFACE FEATURES...WILL IMPACT THE CENTRAL ILLINOIS
TERMINALS THROUGH MUCH OF THE 06Z TAF VALID TIME. THE RAINFALL
ASSOCIATED WITH THIS SYSTEM WILL BE MOST WIDESPREAD FOR THE NEXT
FEW HOURS...BEFORE GRADUALLY TAPERING OFF FROM WEST TO EAST SUNDAY
MORNING. WIDESPREAD IFR/LIFR CONDITIONS ARE ANTICIPATED FOR THE
REST OF THE NIGHT INTO SUNDAY MORNING...WITH ONLY A GRADUAL
IMPROVEMENT TO MVFR EXPECTED AFTER SUNRISE SUNDAY. FURTHER
IMPROVEMENT TO VFR SHOULD HOLD OFF UNTIL SUNDAY EVENING. LIGHT/VARIABLE
WINDS SHOULD PREVAIL THROUGH MIDDAY SUNDAY...BECOMING MORE STEADY
OUT OF THE WEST SUNDAY AFTERNOON AS THE SYSTEM PULLS AWAY.

BAK
&&

.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$








AREA FORECAST DISCUSSION

NWS INDIANAPOLIS IN

 1026 PM EDT MON APR 29 2013

.UPDATE...
AVIATION SECTION HAS BEEN UPDATED BELOW

&&

.SYNOPSIS...
ISSUED AT 315 PM EDT MON APR 29 2013

A DRY AND WARM WEATHER PATTERN HAS BEGUN ACROSS CENTRAL INDIANA
THIS AFTERNOON AND WILL PERSIST THROUGH MID-WEEK. THAT IS WHEN A
BROAD UPPER LEVEL CUTOFF LOW WILL BECOME ANCHORED OVER MUCH OF THE
REGION BRINGING SCATTERED SHOWERS AND THUNDERSTORMS ON THURSDAY
AND FRIDAY. THUNDERSTORM POTENTIAL WILL COME TO AN END BY FRIDAY
NIGHT...BUT RAIN SHOWERS WILL CONTINUE INTO MONDAY AS THE
AFOREMENTIONED UPPER LOW TRACKS ACROSS THE MID-ATLANTIC.

&&

.NEAR TERM /REST OF TONIGHT/...

ISSUED AT 946 PM EDT MON APR 29 2013

FORECAST IS RUNNING ON TRACK AS MID AND HIGH CLOUDS ARE MOVING
INTO THE NORTHERN AND CENTRAL COUNTIES FROM DEVELOPMENT ACROSS
NORTHERN ILLINOIS AND IOWA. HRRR AND RAP STILL KEEP ALL CONVECTION
WELL TO THE NORTH. GOING LOWS IN THE LOW TO MID 50S LOOK GOOD. A
LITTLE CONCERN THAT PATCHY FOG COULD DEVELOP IN THE SOUTHEAST
WHERE CLOUDS WERE LATE TO LEAVE AND WILL BE LATE TO ARRIVE AND
WINDS SHOULD BE A LITTLE LIGHTER...BUT SOUNDINGS DON/T LOOK TOO
FAVORABLE AND DEW POINT DEPRESSIONS ARE STILL PRETTY LARGE. THUS
THOUGHT CHANCE FOR FOG IS STILL LOW ENOUGH AT THIS TIME TO LEAVE
OUT OF FORECAST.

&&

.SHORT TERM /TOMORROW THROUGH THURSDAY/...

ISSUED AT 315 PM EDT MON APR 29 2013

THE FOCUS OF THE SHORT TERM PERIOD IS THE APPROACHING UPPER LEVEL
CUTOFF LOW.

MODELS CONTINUE TO TREND TOWARD A DRY FORECAST THROUGH WEDNESDAY
AS A RIDGE OF HIGH PRESSURE SETS UP OVER THE OHIO VALLEY AND
NORTHEAST. THIS RIDGE WILL BLOCK THE UPPER LEVEL LOW FROM
ENTERING CENTRAL INDIANA UNTIL THURSDAY. FOR NOW...HAVE SLIGHT
CHANCE POPS OVER THE EASTERN COUNTIES AND CHANCE POPS ELSEWHERE
STARTING THURSDAY MORNING. HOWEVER...WOULD NOT BE SURPRISED IF
TIMING OF PRECIP ONSET GETS PUSHED BACK FURTHER.

TEMPS...TRENDED TOWARD THE WARMER GFS FOR TOMORROW...BUT BY
WEDNESDAY...THE NAM FINALLY STARTS PICKING UP ON THE WARMING
TREND. AS A RESULT...WAS ABLE TO GO WITH A MAVMOS BLEND LATE IN
THE SHORT TERM PERIOD. THIS PUTS HIGHS IN THE LOW 80S AND
OVERNIGHT LOWS GENERALLY IN THE UPPER 50S.

&&

.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...

ISSUED AT 255 PM EDT MON APR 29 2013

FOCUS FOR THE EXTENDED REMAINS ON THE EXPECTED DEVELOPMENT OF A
LARGE AND UNUSUALLY STRONG CUTOFF UPPER LOW FOR EARLY MAY ACROSS THE
MIDWEST AND POTENTIAL IMPACTS TO CENTRAL INDIANA. MODELS ARE IN
BETTER AGREEMENT TODAY WITH INITIALLY CUTTING OFF THE UPPER LOW OVER
THE CENTRAL PLAINS ON FRIDAY AS THE BROAD POLAR TROUGH AMPLIFIES.
WHERE THE SYSTEM GOES AFTER THAT THOUGH REMAINS A BIG MYSTERY AND
HINGES TO SOME DEGREE ON POTENTIAL INTERACTION AND PHASING WITH AN
UPPER LOW ALONG THE GULF COAST.

12Z OP GFS CONTINUES TO WAFFLE ON ITS TRACK AND HAS COME IN MUCH
FURTHER SOUTH/EAST WITH THE PROGRESSION OF THE UPPER LOW THROUGH THE
EXTENDED PUTTING IT IN THE CENTRAL APPALACHIANS BY MONDAY NIGHT. 12Z
GGEM OUT INTO THE WEEKEND ALSO APPEARS TO BE TRENDING IN THE
DIRECTION OF THE GFS TRACK. CLOSER ANALYSIS SHOWING THAT BOTH OF
THESE MODELS ARE DEPICTING A STRONGER/SLOWER UPPER LOW ALONG THE
GULF COAST AND CONSEQUENTLY GREATER INTERACTION BETWEEN THE TWO
FEATURES. 12Z ECMWF IS SUPPORTED BY THE UKMET...MAINTAINING A
NORTHERLY TRACK TO THE UPPER LOW INTO THE NORTHERN GREAT LAKES BY
MONDAY BEFORE BECOMING ABSORBED BY A DEEPENING TROUGH OVER WESTERN
CANADA. 12Z GFS ENSEMBLES ONCE AGAIN PROVIDE NO HELP TODAY...
INDICATING WIDE VARIANCE ON THE UPPER LOW TRACK BETWEEN ITS MEMBERS
OVER THE WEEKEND.

CONTINUE TO FAVOR A TRACK CLOSER TO THE ECMWF SOLUTION PARTLY
BECAUSE IT HAS BEEN FAR AND AWAY THE MOST CONSISTENT MODEL WITH
RESPECT TO THE UPPER LOW OVER THE LAST FEW DAYS...AND BECAUSE THE OP
GFS/GGEM TRACK ACROSS THE SOUTHEAST STATES IS HIGHLY UNUSUAL. EVEN
WITH GREATER INTERACTION WITH THE UPPER WAVE ALONG THE GULF
COAST...DO NOT ANTICIPATE THE PARENT UPPER LOW TO BE PULLED THAT FAR
S/E. HAVE DEVIATED LITTLE FROM ALLBLEND WITH SUCH LOW CONFIDENCE ON
THE UPPER LOW TRACK AT THIS POINT...AND WILL CONTINUE TO CARRY POPS
THROUGH THE ENTIRE EXTENDED. HIGHEST CONFIDENCE IN WIDESPREAD
RAINFALL REMAINS ON FRIDAY/SATURDAY WITH LOWER POPS BEYOND THAT.
WILL KEEP HIGHS MAINLY IN THE 60S THROUGH THE PERIOD WITH
EXPECTATION THAT UPPER LOW REMAINS TO THE NORTHWEST OF REGION.
SHOULD A TRACK FURTHER SOUTH INTO THE OHIO VALLEY COME TO
FRUITION...TEMPS WOULD NEED TO BE LOWERED AND POPS RAISED.

&&

AVIATION /DISCUSSION FOR 30030000Z KIND TAF UPDATE/...
ISSUED AT 1026 EDT MON APR 29 2013

MINOR TWEAKS MADE TO KIND TAF PER OBSERVATIONS TO BETTER MATCH
CURRENT CONDITIONS. NO OTHER CHANGES NEEDED AT THIS TIME. PREVIOUS
AVIATION DISCUSSION FOLLOWS...

A PERIOD OF MVFR FOG POSSIBLE 07Z-13Z. OTHERWISE...VFR ALL OTHER
PERIOD.

HIGH PRESSURE ALONG THE EAST COAST AND LOW PRESSURE MOVING INTO THE
CENTRAL PLAINS WILL PRODUCE A LIGHT TO MODERATE SOUTHERLY FLOW
THROUGH THE PERIOD. THE STRATUS OVER EASTERN INDIANA WILL CONTINUE
TO ERODE.  MODEL SOUNDINGS HAVE TRENDED DRIER AND I DO NOT EXPECT
THE STRATUS TO REDEVELOP. MVFR FOG NOT OUT OF THE QUESTION AND WILL
MENTION 4-5 MILES IN TAFS.  THERE WILL BE SOME MID CLOUDS AND A
SLIGHTLY BETTER PRESSURE GRADIENT WHICH SHOULD MINIMIZE THE
DEVELOPMENT OF FOG.

ON TUESDAY...EXPECT SCATTERED CU AND SCATTERED TO BROKEN HIGH CLOUDS
BECOMING MOSTLY CLEAR BY TUESDAY EVENING.

WINDS TONIGHT WILL BE SOUTH AT 5 TO 7 KNOTS AND UP TO 12 KNOTS
TUESDAY.


&&

.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SYNOPSIS...TDUD
NEAR TERM...CP
SHORT TERM...TDUD
LONG TERM....RYAN
AVIATION...JH










AREA FORECAST DISCUSSION

NWS INDIANAPOLIS IN

 957 PM EDT MON APR 29 2013

.UPDATE...
THE NEAR TERM SECTION HAS BEEN UPDATED BELOW

&&

.SYNOPSIS...
ISSUED AT 315 PM EDT MON APR 29 2013

A DRY AND WARM WEATHER PATTERN HAS BEGUN ACROSS CENTRAL INDIANA
THIS AFTERNOON AND WILL PERSIST THROUGH MID-WEEK. THAT IS WHEN A
BROAD UPPER LEVEL CUTOFF LOW WILL BECOME ANCHORED OVER MUCH OF THE
REGION BRINGING SCATTERED SHOWERS AND THUNDERSTORMS ON THURSDAY
AND FRIDAY. THUNDERSTORM POTENTIAL WILL COME TO AN END BY FRIDAY
NIGHT...BUT RAIN SHOWERS WILL CONTINUE INTO MONDAY AS THE
AFOREMENTIONED UPPER LOW TRACKS ACROSS THE MID-ATLANTIC.

&&

.NEAR TERM /REST OF TONIGHT/...

ISSUED AT 946 PM EDT MON APR 29 2013

FORECAST IS RUNNING ON TRACK AS MID AND HIGH CLOUDS ARE MOVING
INTO THE NORTHERN AND CENTRAL COUNTIES FROM DEVELOPMENT ACROSS
NORTHERN ILLINOIS AND IOWA. HRRR AND RAP STILL KEEP ALL CONVECTION
WELL TO THE NORTH. GOING LOWS IN THE LOW TO MID 50S LOOK GOOD. A
LITTLE CONCERN THAT PATCHY FOG COULD DEVELOP IN THE SOUTHEAST
WHERE CLOUDS WERE LATE TO LEAVE AND WILL BE LATE TO ARRIVE AND
WINDS SHOULD BE A LITTLE LIGHTER...BUT SOUNDINGS DON/T LOOK TOO
FAVORABLE AND DEW POINT DEPRESSIONS ARE STILL PRETTY LARGE. THUS
THOUGHT CHANCE FOR FOG IS STILL LOW ENOUGH AT THIS TIME TO LEAVE
OUT OF FORECAST.

&&

.SHORT TERM /TOMORROW THROUGH THURSDAY/...

ISSUED AT 315 PM EDT MON APR 29 2013

THE FOCUS OF THE SHORT TERM PERIOD IS THE APPROACHING UPPER LEVEL
CUTOFF LOW.

MODELS CONTINUE TO TREND TOWARD A DRY FORECAST THROUGH WEDNESDAY
AS A RIDGE OF HIGH PRESSURE SETS UP OVER THE OHIO VALLEY AND
NORTHEAST. THIS RIDGE WILL BLOCK THE UPPER LEVEL LOW FROM
ENTERING CENTRAL INDIANA UNTIL THURSDAY. FOR NOW...HAVE SLIGHT
CHANCE POPS OVER THE EASTERN COUNTIES AND CHANCE POPS ELSEWHERE
STARTING THURSDAY MORNING. HOWEVER...WOULD NOT BE SURPRISED IF
TIMING OF PRECIP ONSET GETS PUSHED BACK FURTHER.

TEMPS...TRENDED TOWARD THE WARMER GFS FOR TOMORROW...BUT BY
WEDNESDAY...THE NAM FINALLY STARTS PICKING UP ON THE WARMING
TREND. AS A RESULT...WAS ABLE TO GO WITH A MAVMOS BLEND LATE IN
THE SHORT TERM PERIOD. THIS PUTS HIGHS IN THE LOW 80S AND
OVERNIGHT LOWS GENERALLY IN THE UPPER 50S.

&&

.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...

ISSUED AT 255 PM EDT MON APR 29 2013

FOCUS FOR THE EXTENDED REMAINS ON THE EXPECTED DEVELOPMENT OF A
LARGE AND UNUSUALLY STRONG CUTOFF UPPER LOW FOR EARLY MAY ACROSS THE
MIDWEST AND POTENTIAL IMPACTS TO CENTRAL INDIANA. MODELS ARE IN
BETTER AGREEMENT TODAY WITH INITIALLY CUTTING OFF THE UPPER LOW OVER
THE CENTRAL PLAINS ON FRIDAY AS THE BROAD POLAR TROUGH AMPLIFIES.
WHERE THE SYSTEM GOES AFTER THAT THOUGH REMAINS A BIG MYSTERY AND
HINGES TO SOME DEGREE ON POTENTIAL INTERACTION AND PHASING WITH AN
UPPER LOW ALONG THE GULF COAST.

12Z OP GFS CONTINUES TO WAFFLE ON ITS TRACK AND HAS COME IN MUCH
FURTHER SOUTH/EAST WITH THE PROGRESSION OF THE UPPER LOW THROUGH THE
EXTENDED PUTTING IT IN THE CENTRAL APPALACHIANS BY MONDAY NIGHT. 12Z
GGEM OUT INTO THE WEEKEND ALSO APPEARS TO BE TRENDING IN THE
DIRECTION OF THE GFS TRACK. CLOSER ANALYSIS SHOWING THAT BOTH OF
THESE MODELS ARE DEPICTING A STRONGER/SLOWER UPPER LOW ALONG THE
GULF COAST AND CONSEQUENTLY GREATER INTERACTION BETWEEN THE TWO
FEATURES. 12Z ECMWF IS SUPPORTED BY THE UKMET...MAINTAINING A
NORTHERLY TRACK TO THE UPPER LOW INTO THE NORTHERN GREAT LAKES BY
MONDAY BEFORE BECOMING ABSORBED BY A DEEPENING TROUGH OVER WESTERN
CANADA. 12Z GFS ENSEMBLES ONCE AGAIN PROVIDE NO HELP TODAY...
INDICATING WIDE VARIANCE ON THE UPPER LOW TRACK BETWEEN ITS MEMBERS
OVER THE WEEKEND.

CONTINUE TO FAVOR A TRACK CLOSER TO THE ECMWF SOLUTION PARTLY
BECAUSE IT HAS BEEN FAR AND AWAY THE MOST CONSISTENT MODEL WITH
RESPECT TO THE UPPER LOW OVER THE LAST FEW DAYS...AND BECAUSE THE OP
GFS/GGEM TRACK ACROSS THE SOUTHEAST STATES IS HIGHLY UNUSUAL. EVEN
WITH GREATER INTERACTION WITH THE UPPER WAVE ALONG THE GULF
COAST...DO NOT ANTICIPATE THE PARENT UPPER LOW TO BE PULLED THAT FAR
S/E. HAVE DEVIATED LITTLE FROM ALLBLEND WITH SUCH LOW CONFIDENCE ON
THE UPPER LOW TRACK AT THIS POINT...AND WILL CONTINUE TO CARRY POPS
THROUGH THE ENTIRE EXTENDED. HIGHEST CONFIDENCE IN WIDESPREAD
RAINFALL REMAINS ON FRIDAY/SATURDAY WITH LOWER POPS BEYOND THAT.
WILL KEEP HIGHS MAINLY IN THE 60S THROUGH THE PERIOD WITH
EXPECTATION THAT UPPER LOW REMAINS TO THE NORTHWEST OF REGION.
SHOULD A TRACK FURTHER SOUTH INTO THE OHIO VALLEY COME TO
FRUITION...TEMPS WOULD NEED TO BE LOWERED AND POPS RAISED.

&&

.AVIATION /DISCUSSION FOR 300000Z TAF ISSUANCE/...
ISSUED AT 650 PM EDT MON APR 29 2013

A PERIOD OF MVFR FOG POSSIBLE 07Z-13Z. OTHERWISE...VFR ALL OTHER
PERIOD.

HIGH PRESSURE ALONG THE EAST COAST AND LOW PRESSURE MOVING INTO THE
CENTRAL PLAINS WILL PRODUCE A LIGHT TO MODERATE SOUTHERLY FLOW
THROUGH THE PERIOD. THE STRATUS OVER EASTERN INDIANA WILL CONTINUE
TO ERODE.  MODEL SOUNDINGS HAVE TRENDED DRIER AND I DO NOT EXPECT
THE STRATUS TO REDEVELOP. MVFR FOG NOT OUT OF THE QUESTION AND WILL
MENTION 4-5 MILES IN TAFS.  THERE WILL BE SOME MID CLOUDS AND A
SLIGHTLY BETTER PRESSURE GRADIENT WHICH SHOULD MINIMIZE THE
DEVELOPMENT OF FOG.

ON TUESDAY...EXPECT SCATTERED CU AND SCATTERED TO BROKEN HIGH CLOUDS
BECOMING MOSTLY CLEAR BY TUESDAY EVENING.

WINDS TONIGHT WILL BE SOUTH AT 5 TO 7 KNOTS AND UP TO 12 KNOTS
TUESDAY.


&&

.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SYNOPSIS...TDUD
NEAR TERM...CP
SHORT TERM...TDUD
LONG TERM....RYAN
AVIATION...JH







AREA FORECAST DISCUSSION

NWS DES MOINES IA

 641 PM CDT MON APR 29 2013

.SHORT TERM.../TONIGHT /...
ISSUED AT 338 PM CDT MON APR 29 2013

MAIN CONCERN FOR THE OVERNIGHT PERIOD WILL BE THE TIMING AND
LOCATION OF ANY CONVECTION. INSTABILITY HAS BEEN ON THE INCREASE
THIS AFTERNOON WITH SBCAPES OF 1000 TO 2000 J/KG ACROSS MUCH OF THE
CWA...AND EVEN HIGHER VALUES AROUND THE MISSOURI BORDER. THE 850 TO
700 MB CAP LOOKS TO WEAKEN AFTER THE 23-00Z TIME FRAME AS A 925MB
MOISTURE PLUME OVER KANSAS AND MISSOURI WORKS NORTHWARD. EXPECTING
CONVECTIVE INITIATION IN THE VICINITY OF THE ASSOCIATED THETA-E
CONVERGENCE ZONE IN SOUTHWEST IOWA OR SOUTHEAST NEBRASKA...WITH THE
CONVECTION TRACKING EAST AND NORTH DURING THE OVERNIGHT. THIRTY TO
FORTY KNOTS OF 0-6 KM SHEAR AND A 40 TO 60 KT LLJ BUILDING IN FROM
THE SOUTHWEST AFTER 03Z WILL AID IN INTENSIFYING AND MAINTAINING ANY
STORMS THAT DO FORM THIS EVENING. BOTH ELEVATED AND SURFACE BASED
CONVECTION IS POSSIBLE WITH THE MAIN THREAT FROM THESE STORMS BEING
LARGE HAIL AND DAMAGING WIND GUSTS.

MANY HIGH RESOLUTION MODELS HAVE BEEN TRENDING THE CONVECTION
SLIGHTLY NORTH AND WEST TODAY. THIS HAS ALSO BEEN REFLECTED IN THE
UPDATED SPC CONVECTIVE DAY 1 SLIGHT RISK OUTLOOKS. IN
GENERAL...LEANED TOWARDS A COMBINATION OF THE EAST NMM AND ARW WRF
CORES AND THE 16Z HRRR FOR PLACEMENT OF THE HIGHEST POPS AND QPF
AMOUNTS. HEAVY RAINFALL IS POSSIBLE WITH SOME OF THESE STORMS OVER
CENTRAL IOWA WITH PWATS EXCEEDING ONE INCH AND LOW LEVEL MIXING
RATIOS AROUND 13 G/KG.

STATIONARY SURFACE BOUNDARY OVER WEST CENTRAL AND NORTH CENTRAL IOWA
WASHED OUT EARLY THIS AFTERNOON...ALLOWING WINDS TO VEER SOUTHWARD
AND TEMPERATURES TO RISE BACK INTO THE 70S. THESE SOUTHERLY WINDS
WILL INCREASE OVERNIGHT AS THE PRESSURE GRADIENT TIGHTENS IN RESPONSE
TO AN APPROACHING NORTHERN PLAINS COLD FRONT. COMBINED WITH DEW POINTS IN
THE UPPER 50S TO NEAR 60...EXPECT OVERNIGHT LOWS TO ONLY FALL OFF
INTO THE LOW 60S.

.LONG TERM.../TUESDAY THROUGH MONDAY/...
ISSUED AT 338 PM CDT MON APR 29 2013

I EXPECT SOME ONGOING CONVECTION MAINLY ACROSS THE EAST IN THE
MORNING WITH A LULL LATE MORNING.  ANOTHER COLD FRONT WILL STRETCH
ACROSS CENTRAL IOWA DURING THE DAY ON TUESDAY AND MAKE SLOW ESE
PROGRESS.  FORECAST SOUNDINGS SHOW A PRETTY STOUT CAP IN PLACE BUT
IT QUICKLY ERODES DURING THE MID TO LATE AFTERNOON AND INTO THE
EVENING AND THIS IS WHEN I EXPECT THUNDERSTORMS TO BREAK OUT...AHEAD
OF THE BOUNDARY.  LOOKING AT SHEAR...THERE IS SOME THAT EXISTS ALONG
THE BOUNDARY BUT THE BEST SHEAR IS FOUND BEHIND THE BOUNDARY.  SOME
STORMS COULD PRODUCE LARGE HAIL AND DAMAGING WIND.  DURING TUESDAY
EVENING ADDITIONAL STORMS COULD DEVELOP BEHIND THE FRONT AS WELL
WHERE THE BETTER SHEAR WILL EXIST AND THERE WILL STILL BE SOME
INSTABILITY.

ON WEDNESDAY THE UPPER TROUGH OUT TO THE WEST WILL DIG SOUTH ON THE
LEE SIDE OF THE ROCKIES CREATING QUITE THE TEMPERATURE GRADIENT
ACROSS IOWA.  ACROSS THE NORTHWEST HALF TO TWO THIRDS OF THE STATE
HIGHS WILL ONLY BE IN THE 40S AND 50S WHILE ACROSS THE SOUTHEAST
TEMPERATURES WILL BE IN THE 60S TO 70S.  THIS TROUGH WILL CONTINUE
TO DIG AS IT PLOWS EAST THROUGH THURSDAY.  FORECAST SOUNDINGS ON
THURSDAY SHOW FALLING TEMPERATURES THROUGHOUT THE AFTERNOON HOURS.
IN FACT IT LOOKS LIKE HIGHS WILL LIKELY BE REACHED IN THE MORNING
AND THOSE READINGS WILL ONLY BE IN THE 40S.  PRETTY DECENT MOISTURE
TRANSPORT WILL TAKE PLACE DURING THIS TIME AND PRECIPITATION WILL
YIELD SOME PRETTY HIGH QPF VALUES THROUGH THE REMAINDER OF THE
WEEK.  FORECAST SOUNDINGS SHOW THAT WE WILL BE COLD ENOUGH FOR AT
MINIMUM A RAIN/SNOW MIX DURING THE DAY ON THURSDAY.  IF YOU BELIEVE
THE NAM WE WILL BE COLD ENOUGH FOR ALL SNOW.  I HAD A HARD TIME
BUYING INTO THAT SOLUTION COMPLETELY BECAUSE FOR THE PAST FEW DAYS
THE NAM HAD BEEN OVERDOING THE MOISTURE AND THE COOLING.  THIS WILL
CERTAINLY BEAR WATCHING BUT I WOULD NOT BE SURPRISED TO SEE SNOW
THURSDAY AFTERNOON AND THURSDAY NIGHT.

BEYOND THIS PERIOD...THE MODELS CONTINUE TO POORLY HANDLE THE
EVOLUTION OF THE CLOSED LOW THAT DEVELOPS OUT OF THE TROUGH.  THE
EURO LIFTS THIS CLOSED LOW INTO IOWA OVER THE WEEKEND THEN INTO THE
GREAT LAKES ON MONDAY WHILE THE GFS AND GEM TAKE THE LOW TO THE
SOUTH ACROSS THE SOUTHERN PLAINS.  THIS SOLUTION WOULD DRAW DOWN
MUCH COLDER AIR ACROSS THE STATE FOR THE WEEKEND.  I TRIED TO LEAN
COOLER BUT BY SUNDAY FORECAST SOUNDINGS SUPPORT HIGHS IN THE 50S. AT
THIS POINT I KEPT 40S NW TO 50S SE ON SATURDAY BUT WE COULD INDEED
SEE TEMPS SOME 5 TO 8 DEGREES COOLER THAT WHAT I HAVE GOING.  WE
WILL NEED TO SEE HOW THAT CLOSED LOW EVOLVES AND SHIFTS ACROSS THE
AREA.  BEFORE THAT HAPPENS THERE IS JUST TOO MUCH MODEL UNCERTAINTY
TO STATE A PREFERENCE.

&&

.AVIATION...30/00Z
ISSUED AT 634 PM CDT MON APR 29 2013

ANTICIPATE AREAS OF SHOWERS AND THUNDERSTORMS TO DEVELOP NEAR 03Z
AND SPREAD NE ACROSS SITES. HAVE INCLUDED VICINITY MENTION AT
SITES FOR NOW...WITH SCATTERED NATURE OF STORMS. CEILINGS SHOULD
REMAIN VFR...THOUGH COULD SEE HIGH MVFR CEILINGS AT TIMES WITH
PRECIPITATION. WINDS WILL INCREASE THROUGH THE OVERNIGHT AND SHIFT
TO THE SOUTHWEST BY TUESDAY AFTERNOON...BECOMING GUSTY.

&&

.HYDROLOGY...
ISSUED AT 338 PM CDT MON APR 29 2013

HE MODERATE TO HEAVY RAINFALL EVENT FORECAST IN THE LONG TERM
PERIOD OF THE FORECAST MAY RESULT IN SIGNIFICANT WITHIN-BANK RISES
ALONG MANY STREAMS AND RIVERS. FLOODING IS ALSO
POSSIBLE...ESPECIALLY ALONG THE SMALLER STREAMS AND IN AREAS THAT
RECEIVE HEAVIER RAINFALL. AT THIS TIME IT IS DIFFICULT TO PINPOINT
SPECIFIC STREAMS OR RIVERS GIVEN THE UNCERTAINTY IN THE RAINFALL
FORECAST. THE FORECAST WILL HAVE TO BE MONITORED FOR POTENTIAL
IMPACTS ON AREA RIVERS.

&&

.DMX WATCHES/WARNINGS/ADVISORIES...NONE.

&&

$$

SHORT TERM...SKOW
LONG TERM...FAB
AVIATION...AWB
HYDROLOGY...ZOGG







AREA FORECAST DISCUSSION

NWS DODGE CITY KS

 702 AM CDT SUN APR 28 2013

...UPDATED AVIATION SECTION FOR 12Z TAFS...

.SYNOPSIS...
ISSUED AT 400 AM CDT SUN APR 28 2013

SPLIT FLOW WAS IN PLACE ACROSS NORTH AMERICA WITH THE MAIN JET
ENERGY MOVING ACROSS WESTERN KANSAS AND THE PACIFIC NORTHWEST
REGION. ANOTHER UPPER JET AXIS WAS MOVING ACROSS MEXICO AND THE
SOUTHERN UNITED STATES. THE SYNOPTIC SCALE UPPER TROUGH WAS
POSITIONED ACROSS IOWA AND MISSOURI, WITH THE 850 MB EXTENDING
FARTHER SOUTH ACROSS THE SOUTHERN MISSISSIPPI VALLEY BASED ON THE 00
UTC SUBJECTIVE ANALYSIS. FARTHER WEST, A LARGE THERMAL GRADIENT
EXISTED ACROSS KANSAS INTO THE CENTRAL AND SOUTHERN ROCKIES AS 850
MB TEMPERATURES WERE AROUND 20 DEGREES C FROM RAP TO LBF, DDC AND
AMA. SURFACE TEMPERATURES ACROSS WESTERN KANSAS REMAINED MILD
THROUGH THE OVERNIGHT, RANGING FROM THE UPPER 40`S TO LOW 50`S
THROUGH AROUND 2 AM.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 400 AM CDT SUN APR 28 2013

THE MODELS DEVELOP A DRYLINE SHIFTING ACROSS THE AREA LATER TODAY
AS WEAK VERTICAL MIXING DEVELOPS. HOWEVER, LIGHT BOUNDARY LAYER
WINDS ARE IN PLACE AND LITTLE IF ANY GUSTING SEEMS POSSIBLE. THE
FULL AVAILABLE LATE APRIL INSOLATION WILL HELP TEMPERATURES SOAR IN
THE LATE MORNING AND EARLY AFTERNOON. MODELS ACROSS THE BOARD
FORECAST HIGHS IN THE MID TO UPPER 80`S FOR THIS AFTERNOON. THERE
DOES APPEAR TO BE A RAPID INCREASE IN SURFACE BASED CAPE ACROSS
CENTRAL KANSAS DURING THE LATE AFTERNOON. HOWEVER THE MODELS WORK
DRIER AIR FARTHER EAST INTO CENTRAL KANSAS IN THE AFTERNOON,
RELEGATING THE BEST SURFACE BASED CONVECTIVE AVAILABLE ENERGY
FARTHER EAST ACROSS EASTERN KANSAS. WITHOUT ANY UPPER SUPPORT, AND
LIMITED TO NONEXISTENT SBCAPE, EVEN ISOLATED STORMS DO NOT LOOK
LIKELY LATER TODAY.

WITH EXPECTED GOOD RADIATIONAL COOLING AND A RETREATING DRYLINE,
ANOTHER MILD NIGHT CAN BE EXPECTED. LOWS WILL REACH THE 40`S OVER
MOST OF SOUTHWEST KANSAS, TO LOW 50`S OVER THE CENTRAL SECTIONS.


.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 400 AM CDT SUN APR 28 2013

THE LONG TERM FORECAST FOR THE MIDDLE AND LATTER PORTION OF THE WEEK
IS FRAUGHT WITH CHALLENGES AS A DEEP TROUGH DEVELOPS AND A CLOSED
LOW FORMS OUT OF THE TROUGH...EVENTUALLY BECOMING CUT OFF FROM THE
MAIN POLAR JET STREAM FLOW. PRIOR TO THE STORM SYSTEM
DEVELOPMENT...TEMPERATURES WILL SOAR INTO THE UPPER 80S TO NEAR 90
BOTH MONDAY AND TUESDAY. A LEAD SHORTWAVE MOVING EAST ACROSS THE
DAKOTAS MONDAY WILL PUSH A SUBTLE FRONTAL BOUNDARY SOUTHWARD WHICH
COULD PREVENT AREAS NORTH OF HIGHWAY 96 FROM WARMING WELL INTO THE
80S LIKE THE SOUTHERN COUNTIES.  WILL BE HEDGING COOLER IN THE
FORECAST FOR THIS REASON UP NORTH...ESPECIALLY WAKEENEY TO HAYS. ON
TUESDAY...THE ECMWF SHOWS A 992MB SURFACE LOW OVER SOUTHEASTERN
COLORADO WITH A DRYLINE TAKING SHAPE EAST OF THE LOW. THE LEAD
FRONTAL BOUNDARY WILL LIKELY PUSH NORTH LATE MONDAY NIGHT INTO EARLY
TUESDAY BEFORE MOVING BACK SOUTH DURING THE DAY TUESDAY.
AGAIN...THIS WILL LEAD TO QUITE THE CHALLENGE IN HIGH TEMPERATURE
FORECAST. FEEL PRETTY CONFIDENT, THOUGH, THAT SOME 90-92 DEGREE
TEMPERATURES WILL BE FOUND SOUTHWEST OF A JOHNSON TO ASHLAND LINE.

EVEN THOUGH THERE ARE SOME 15-20 POPS IN THE FORECAST UP IN CENTRAL
KANSAS (ELLIS-RUSH COUNTIES) LATE IN THE DAY TUESDAY...THE FEELING
IS THAT CONVECTION WILL HOLD OFF UNTIL TUESDAY EVENING AND
ESPECIALLY DURING THE NIGHT. ADVANCE OF 58 TO 61F DEWPOINTS INTO
SOUTH CENTRAL AND CENTRAL KANSAS AND VERY WARM SURFACE TEMPERATURES
WILL LEAD TO 2000 TO 2500 J/KG OF CAPE TUESDAY EVENING. THE PROBLEM
IS THAT THE 800-700MB LAYER WILL BE EXTREMELY WARM LIKELY PREVENTING
SURFACE BASED CONVECTION ON THE DRYLINE SOUTH OF THE FRONT. THE MOST
LIKELY SCENARIO IS CONVECTION FORMING AT THE NOSE OF A DEVELOPING
LOW LEVEL JUST JUST AFTER SUNSET...AND THIS IS WHEN POPS WILL
INCREASE IN THE FORECAST TO 30 TO 40 PERCENT...ESPECIALLY ALONG AND
NORTH OF HIGHWAY 96.

SOMETIME AFTER MIDNIGHT TUESDAY NIGHT...THE TRUE COLD AIR WILL BE
CHARGING SOUTH THROUGH NEBRASKA AND INTO KANSAS AS THE DEEP UPPER
TROUGH APPROACHES. TEMPERATURES IN THE 50S AND LOWER 60S WILL BE
COMMON OVERNIGHT AHEAD OF THE FRONT. THE QUESTION IS TIMING AND WILL
HAVE A HUGE IMPACT ON DAYTIME TEMPERATURES WEDNESDAY ACROSS
SOUTHWEST AND SOUTH CENTRAL KANSAS. AT THIS TIME...THE BEST FORECAST
IS A FRONTAL PASSAGE SOMETIME EARLY TO MID-MORNING A FEW HOURS AFTER
SUNRISE WHEREBY THERE COULD BE A BRIEF, BUT DECENT WARM-UP BEFORE
THE RUG IS PULLED UNDERNEATH US IN THE TEMPERATURE DEPARTMENT...AKIN
TO WHAT WE SAW A COUPLE OF TIMES IN APRIL WITH TREMENDOUS COLD AIR
ADVECTION ON THE ORDER OF 20 TO 30 DEGREE FALL IN TEMPERATURE OVER
THE SPAN OF JUST A FEW HOURS. THE OFFICIAL TEMPERATURE FORECAST WILL
TRY TO REFLECT A FAIRLY ROBUST DIURNAL FALL ON WEDNESDAY ACROSS MUCH
OF THE AREA.  RAIN SHOWERS WILL BE LIKELY ESPECIALLY ACROSS CENTRAL
AND SOUTH-CENTRAL KANSAS WITH A FEW EMBEDDED THUNDERSTORMS.

FRONTOGENESIS IN THE 800-700MB LAYER WILL BE STRENGTHENING LATE IN
THE DAY WEDNESDAY AND WEDNESDAY NIGHT ACROSS WESTERN KANSAS WITH THE
THERMODYNAMIC PROFILE RAPIDLY COOLING TO THE POINT THAT FROZEN
PRECIPITATION WILL ENTER THE PICTURE. THERE WILL LIKELY BE A NARROW
CORRIDOR OF SLEET DEVELOPING LATE WEDNESDAY ACROSS FAR WEST-CENTRAL
KANSAS BUT QUICKLY CHANGING TO WET SNOW AS SURFACE TEMPERATURES
CONTINUE TO FALL THROUGH THE LOWER 30S. AFTER WEDNESDAY
NIGHT...THERE IS CONSIDERABLE DIVERGENCE IN VARIOUS MODEL SOLUTIONS
REGARDING THE DEVELOPMENT OF THE MID LEVEL CYCLONE.  THE LATEST
ECMWF MODEL IS NOW BACK TO A MORE PROGRESSIVE SCENARIO RESULTING IN
THE LOW CLOSING OFF A BIT FARTHER EAST THAN YESTERDAY`S 12Z RUN. THE
LATEST 00Z VERSION OF THE CANADIAN GEM, ON THE OTHER HAND, HAS A
MUCH MORE FAVORABLE SCENARIO FOR LONGER-DURATION PRECIPITATION EVENT
AFFECTING CENTRAL AND SOUTH-CENTRAL KANSAS THURSDAY AND FRIDAY.
THIS STILL SEEMS LIKE AN OUTLIER SCENARIO SO POPS ON THURSDAY NIGHT
AND FRIDAY WILL BE IN THE SLIGHT CHANCE RANGE AND ONLY ACROSS THE
EASTERN COUNTIES (CENTRAL AND SOUTH-CENTRAL KANSAS).

A HISTORICAL NOTE OF REFERENCE REGARDING LATE-SEASON SNOW AT DODGE
CITY: THERE HAVE ONLY BEEN THREE OCCURRENCES IN THE HISTORY OF
WEATHER RECORDS OF MEASURABLE SNOW IN THE MONTH OF MAY AT DODGE CITY:

1) 0.9 INCHES ON 3 MAY 1978
2) 0.7 INCHES ON 6 MAY 1915
3) 0.3 INCHES ON 4 MAY 1979

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 700 AM CDT SUN APR 28 2013

QUIET AVIATION WEATHER IS EXPECTED TODAY AND TONIGHT IN A DRY
NORTHWEST FLOW REGIME. A WEAK LEE TROUGH AXIS WILL EXTEND FROM FAR
WESTERN KANSAS THROUGH CENTRAL NEBRASKA WITH WIND SPEEDS GENERALLY
FROM THE SOUTHWEST OR WEST-SOUTHWEST AT 7 TO 11 KNOTS. VFR
CONDITIONS ARE EXPECTED THROUGH MONDAY.

&&

.PRELIMINARY POINT TEMPS/POPS...
DDC  87  49  87  56 /   0   0  10  10
GCK  87  47  86  53 /   0   0   0  10
EHA  86  46  90  54 /   0   0   0   0
LBL  87  49  90  55 /   0   0   0   0
HYS  88  52  81  55 /   0  10  10  10
P28  85  54  88  58 /   0  10  10  10

&&

.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SYNOPSIS...RUSSELL
SHORT TERM...RUSSELL
LONG TERM...UMSCHEID
AVIATION...UMSCHEID







AREA FORECAST DISCUSSION

NWS DODGE CITY KS

 403 AM CDT SUN APR 28 2013


.SYNOPSIS...
ISSUED AT 400 AM CDT SUN APR 28 2013

SPLIT FLOW WAS IN PLACE ACROSS NORTH AMERICA WITH THE MAIN JET
ENERGY MOVING ACROSS WESTERN KANSAS AND THE PACIFIC NORTHWEST
REGION. ANOTHER UPPER JET AXIS WAS MOVING ACROSS MEXICO AND THE
SOUTHERN UNITED STATES. THE SYNOPTIC SCALE UPPER TROUGH WAS
POSITIONED ACROSS IOWA AND MISSOURI, WITH THE 850 MB EXTENDING
FARTHER SOUTH ACROSS THE SOUTHERN MISSISSIPPI VALLEY BASED ON THE 00
UTC SUBJECTIVE ANALYSIS. FARTHER WEST, A LARGE THERMAL GRADIENT
EXISTED ACROSS KANSAS INTO THE CENTRAL AND SOUTHERN ROCKIES AS 850
MB TEMPERATURES WERE AROUND 20 DEGREES C FROM RAP TO LBF, DDC AND
AMA. SURFACE TEMPERATURES ACROSS WESTERN KANSAS REMAINED MILD
THROUGH THE OVERNIGHT, RANGING FROM THE UPPER 40`S TO LOW 50`S
THROUGH AROUND 2 AM.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 400 AM CDT SUN APR 28 2013

THE MODELS DEVELOP A DRYLINE SHIFTING ACROSS THE AREA LATER TODAY
AS WEAK VERTICAL MIXING DEVELOPS. HOWEVER, LIGHT BOUNDARY LAYER
WINDS ARE IN PLACE AND LITTLE IF ANY GUSTING SEEMS POSSIBLE. THE
FULL AVAILABLE LATE APRIL INSOLATION WILL HELP TEMPERATURES SOAR IN
THE LATE MORNING AND EARLY AFTERNOON. MODELS ACROSS THE BOARD
FORECAST HIGHS IN THE MID TO UPPER 80`S FOR THIS AFTERNOON. THERE
DOES APPEAR TO BE A RAPID INCREASE IN SURFACE BASED CAPE ACROSS
CENTRAL KANSAS DURING THE LATE AFTERNOON. HOWEVER THE MODELS WORK
DRIER AIR FARTHER EAST INTO CENTRAL KANSAS IN THE AFTERNOON,
RELEGATING THE BEST SURFACE BASED CONVECTIVE AVAILABLE ENERGY
FARTHER EAST ACROSS EASTERN KANSAS. WITHOUT ANY UPPER SUPPORT, AND
LIMITED TO NONEXISTENT SBCAPE, EVEN ISOLATED STORMS DO NOT LOOK
LIKELY LATER TODAY.

WITH EXPECTED GOOD RADIATIONAL COOLING AND A RETREATING DRYLINE,
ANOTHER MILD NIGHT CAN BE EXPECTED. LOWS WILL REACH THE 40`S OVER
MOST OF SOUTHWEST KANSAS, TO LOW 50`S OVER THE CENTRAL SECTIONS.



.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 400 AM CDT SUN APR 28 2013

THE LONG TERM FORECAST FOR THE MIDDLE AND LATTER PORTION OF THE WEEK
IS FRAUGHT WITH CHALLENGES AS A DEEP TROUGH DEVELOPS AND A CLOSED
LOW FORMS OUT OF THE TROUGH...EVENTUALLY BECOMING CUT OFF FROM THE
MAIN POLAR JET STREAM FLOW. PRIOR TO THE STORM SYSTEM
DEVELOPMENT...TEMPERATURES WILL SOAR INTO THE UPPER 80S TO NEAR 90
BOTH MONDAY AND TUESDAY. A LEAD SHORTWAVE MOVING EAST ACROSS THE
DAKOTAS MONDAY WILL PUSH A SUBTLE FRONTAL BOUNDARY SOUTHWARD WHICH
COULD PREVENT AREAS NORTH OF HIGHWAY 96 FROM WARMING WELL INTO THE
80S LIKE THE SOUTHERN COUNTIES.  WILL BE HEDGING COOLER IN THE
FORECAST FOR THIS REASON UP NORTH...ESPECIALLY WAKEENEY TO HAYS. ON
TUESDAY...THE ECMWF SHOWS A 992MB SURFACE LOW OVER SOUTHEASTERN
COLORADO WITH A DRYLINE TAKING SHAPE EAST OF THE LOW. THE LEAD
FRONTAL BOUNDARY WILL LIKELY PUSH NORTH LATE MONDAY NIGHT INTO EARLY
TUESDAY BEFORE MOVING BACK SOUTH DURING THE DAY TUESDAY.
AGAIN...THIS WILL LEAD TO QUITE THE CHALLENGE IN HIGH TEMPERATURE
FORECAST. FEEL PRETTY CONFIDENT, THOUGH, THAT SOME 90-92 DEGREE
TEMPERATURES WILL BE FOUND SOUTHWEST OF A JOHNSON TO ASHLAND LINE.

EVEN THOUGH THERE ARE SOME 15-20 POPS IN THE FORECAST UP IN CENTRAL
KANSAS (ELLIS-RUSH COUNTIES) LATE IN THE DAY TUESDAY...THE FEELING
IS THAT CONVECTION WILL HOLD OFF UNTIL TUESDAY EVENING AND
ESPECIALLY DURING THE NIGHT. ADVANCE OF 58 TO 61F DEWPOINTS INTO
SOUTH CENTRAL AND CENTRAL KANSAS AND VERY WARM SURFACE TEMPERATURES
WILL LEAD TO 2000 TO 2500 J/KG OF CAPE TUESDAY EVENING. THE PROBLEM
IS THAT THE 800-700MB LAYER WILL BE EXTREMELY WARM LIKELY PREVENTING
SURFACE BASED CONVECTION ON THE DRYLINE SOUTH OF THE FRONT. THE MOST
LIKELY SCENARIO IS CONVECTION FORMING AT THE NOSE OF A DEVELOPING
LOW LEVEL JUST JUST AFTER SUNSET...AND THIS IS WHEN POPS WILL
INCREASE IN THE FORECAST TO 30 TO 40 PERCENT...ESPECIALLY ALONG AND
NORTH OF HIGHWAY 96.

SOMETIME AFTER MIDNIGHT TUESDAY NIGHT...THE TRUE COLD AIR WILL BE
CHARGING SOUTH THROUGH NEBRASKA AND INTO KANSAS AS THE DEEP UPPER
TROUGH APPROACHES. TEMPERATURES IN THE 50S AND LOWER 60S WILL BE
COMMON OVERNIGHT AHEAD OF THE FRONT. THE QUESTION IS TIMING AND WILL
HAVE A HUGE IMPACT ON DAYTIME TEMPERATURES WEDNESDAY ACROSS
SOUTHWEST AND SOUTH CENTRAL KANSAS. AT THIS TIME...THE BEST FORECAST
IS A FRONTAL PASSAGE SOMETIME EARLY TO MID-MORNING A FEW HOURS AFTER
SUNRISE WHEREBY THERE COULD BE A BRIEF, BUT DECENT WARM-UP BEFORE
THE RUG IS PULLED UNDERNEATH US IN THE TEMPERATURE DEPARTMENT...AKIN
TO WHAT WE SAW A COUPLE OF TIMES IN APRIL WITH TREMENDOUS COLD AIR
ADVECTION ON THE ORDER OF 20 TO 30 DEGREE FALL IN TEMPERATURE OVER
THE SPAN OF JUST A FEW HOURS. THE OFFICIAL TEMPERATURE FORECAST WILL
TRY TO REFLECT A FAIRLY ROBUST DIURNAL FALL ON WEDNESDAY ACROSS MUCH
OF THE AREA.  RAIN SHOWERS WILL BE LIKELY ESPECIALLY ACROSS CENTRAL
AND SOUTH-CENTRAL KANSAS WITH A FEW EMBEDDED THUNDERSTORMS.

FRONTOGENESIS IN THE 800-700MB LAYER WILL BE STRENGTHENING LATE IN
THE DAY WEDNESDAY AND WEDNESDAY NIGHT ACROSS WESTERN KANSAS WITH THE
THERMODYNAMIC PROFILE RAPIDLY COOLING TO THE POINT THAT FROZEN
PRECIPITATION WILL ENTER THE PICTURE. THERE WILL LIKELY BE A NARROW
CORRIDOR OF SLEET DEVELOPING LATE WEDNESDAY ACROSS FAR WEST-CENTRAL
KANSAS BUT QUICKLY CHANGING TO WET SNOW AS SURFACE TEMPERATURES
CONTINUE TO FALL THROUGH THE LOWER 30S. AFTER WEDNESDAY
NIGHT...THERE IS CONSIDERABLE DIVERGENCE IN VARIOUS MODEL SOLUTIONS
REGARDING THE DEVELOPMENT OF THE MID LEVEL CYCLONE.  THE LATEST
ECMWF MODEL IS NOW BACK TO A MORE PROGRESSIVE SCENARIO RESULTING IN
THE LOW CLOSING OFF A BIT FARTHER EAST THAN YESTERDAY`S 12Z RUN. THE
LATEST 00Z VERSION OF THE CANADIAN GEM, ON THE OTHER HAND, HAS A
MUCH MORE FAVORABLE SCENARIO FOR LONGER-DURATION PRECIPITATION EVENT
AFFECTING CENTRAL AND SOUTH-CENTRAL KANSAS THURSDAY AND FRIDAY.
THIS STILL SEEMS LIKE AN OUTLIER SCENARIO SO POPS ON THURSDAY NIGHT
AND FRIDAY WILL BE IN THE SLIGHT CHANCE RANGE AND ONLY ACROSS THE
EASTERN COUNTIES (CENTRAL AND SOUTH-CENTRAL KANSAS).

A HISTORICAL NOTE OF REFERENCE REGARDING LATE-SEASON SNOW AT DODGE
CITY: THERE HAVE ONLY BEEN THREE OCCURRENCES IN THE HISTORY OF
WEATHER RECORDS OF MEASURABLE SNOW IN THE MONTH OF MAY AT DODGE CITY:

1) 0.9 INCHES ON 3 MAY 1978
2) 0.7 INCHES ON 6 MAY 1915
3) 0.3 INCHES ON 4 MAY 1979

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1233 AM CDT SUN APR 28 2013

LIGHT BOUNDARY LAYER WINDS DUE TO A WEAK PRESSURE GRADIENT ACROSS
SOUTHWEST KANSAS WILL CONTINUE OVERNIGHT.  6 TO 8 DEGREE C DEW POINT
DEPRESSIONS FROM THE SURFACE TO THE MID LAYERS WILL HINDER ANY
STRATUS DEVELOP THROUGH THE OVERNIGHT AS WELL. THE RAPID REFRESH AND
LOCAL GFS MOS BOTH TREND WIND DIRECTION TOWARD THE SOUTHWEST AFTER
MIDNIGHT, WHICH IS ALSO UNFAVORABLE FOR FOG DEVELOPMENT.
VFR CONDITIONS ARE EXPECTED THROUGH THE TAF PERIOD.


&&

.PRELIMINARY POINT TEMPS/POPS...
DDC  87  49  87  56 /   0   0  10  10
GCK  87  47  86  53 /   0   0   0  10
EHA  86  46  90  54 /   0   0   0   0
LBL  87  49  90  55 /   0   0   0   0
HYS  88  52  81  55 /   0  10  10  10
P28  85  54  88  58 /   0  10  10  10

&&

.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SYNOPSIS...RUSSELL
SHORT TERM...RUSSELL
LONG TERM...UMSCHEID
AVIATION...RUSSELL








AREA FORECAST DISCUSSION

NWS WAKEFIELD VA

 405 PM EDT SUN APR 28 2013

.SYNOPSIS...
HIGH PRESSURE WILL REMAIN JUST OFFSHORE THROUGH MONDAY...AS LOW
PRESSURE LIFTS NORTHEAST FROM THE MISSISSIPPI VALLEY INTO THE OHIO
VALLEY. THIS AREA OF LOW PRESSURE WILL VERY SLOWLY TRACK ACROSS
THE MID ATLANTIC REGION TONIGHT THROUGH MONDAY NIGHT. LOW PRESSURE
LINGERS OFF THE CAROLINA COAST THROUGH MIDWEEK AS HIGH PRESSURE
REMAINS ANCHORED OVER THE CANADIAN MARITIMES.

&&

.NEAR TERM /THROUGH TONIGHT/...
THE LATEST WX ANALYSIS SHOWS ~1028MB SURFACE HIGH WHICH REMAINS
ORIENTED JUST OFF THE MID- ATLANTIC/NORTHEAST COAST. TO THE WEST,
WEAKENING MID/UPPER LEVEL LOW PRESSURE HAS WEAKENED TO AN OPEN
WAVE AS IT CONTINUES TO SLOWLY LIFT NE FROM THE CHICAGOLAND AREA
INTO THE UPPER GREAT LAKES. AREA OF LIGHT RAIN HAS INCREASED ALONG
AND AHEAD OF SLOW MOVING COLD FRONT DRAPED ACROSS THE OH/TN VLY.
CLOSER TO HOME, CLOUD COVER HAS CONTINUED TO THICKEN AND LOWER AS
EXPECTED EARLY THIS AFTN AS EXPECTED, ESPECIALLY ACROSS THE
PIEDMONT. HOWEVER...DESPITE INCREASING CLDS THIS AFTN, THE
INFLUENCE OF THE HIGH ALONG THE EASTERN SEABOARD WILL RESULT IN
PERSISTENT LOW- LEVEL DRY AIR (BELOW 800MB) OVER THE LOCAL AREA
PER FORECAST BUFR SOUNDINGS. GIVEN THIS...WILL DOWNPLAY WIDESPREAD
POPS W/THE USE OF A GENERAL PERSISTENCE FORECAST (WHICH JIVES WELL
WITH RUC DEPICTION OF POPS) FOR THE NEXT FEW HOURS. RAIN CHANCES
HV BEEN BUMPED INTO LKLY RANGE FOR FAR WESTERN PIEDMONT, WITH
SLIGHT CHC/LOW CHANCE POPS FARTHER EAST FOR THE REST OF THE
AFTERNOON.

THERE IS VERY LITTLE CHANGE IN THE LOW-LEVEL THERMAL PROFILE FROM
YESTERDAY,SO THE MAIN INFLUENCE ON HIGH TEMPERATURES WILL BE
INCREASING CLOUD COVER. THIS HAS HELD MAXIMA LARGELY IN THE
MID/UPPER 60S. EAST OF I-95...TEMPERATURES HV REACHED TO ~70/LOW
70S, AND HAVE EVEN DROPPED OFF SLIGHTLY AS CLDS HV BUILT EAST OVER
THE PAST FEW HRS.

RAIN CHANCES GRADUALLY INCREASE TONIGHT AS UPPER TROUGH
APPROACHES THROUGH LATE TONIGHT. INCREASING SYNOPTIC LIFT WILL
SHUNT A STEADY STREAM OF MOISTURE ADVECTION ACROSS THE AREA
TONIGHT, WHICH DEVELOPS ALONG THE EAST COAST. THIS INCREASE IN PW
IS THE RESULT OF THE APPROACHING TROUGH TO THE WEST AND
AFOREMENTIONED QUASI- STATIONARY HIGH TO THE EAST. THIS MOISTURE
TRANSPORT (GOOD MODEL AGREEMENT IN INCREASING PW VALUES TO ~1.3IN)
WILL OFFSET WEAKENING DYNAMICS AND YIELD A PERIOD OF LIGHT TO
MODERATE PCPN LATE TONIGHT INTO MONDAY MORNING. HAVE
CONTINUED/INCREASED POPS INTO CATEGORICAL RANGE WEST OF THE BAY
AFTER 00Z/8P EDT, WITH RAIN CHANCES INCREASING OVER THE EASTERN
SHORE AFTER 06Z/2AM MONDAY.

FOR LOWS, CLOUDY SKY AND MOISTENING LLVLS SHOULD KEEP HIGHS MILD.
EARLY MORNING LOWS IN THE MID 50S TO NR 60.

&&

.SHORT TERM /MONDAY THROUGH WEDNESDAY/...
BY MONDAY...THE TROUGH AXIS VERY SLOWLY APPROACHES THE WESTERN
PORTION OF THE AREA MONDAY MORNING. STEADY STRATIFORM RAIN TAPERS
TO SOME SHRAS WEST OF I-95 MONDAY AFTN AS THE BEST MOISTURE
TRANSPORT GRADUALLY SHIFTS TOWARD THE COAST. 12Z GFS/NAM EACH
SHUNT OMEGA MAX FROM THE THE EASTERN CAROLINAS ACROSS ATLANTIC
COASTAL AREAS MONDAY AFTERNOON AND EVENING...WHICH MESHES WELL
WITH PROGGED AREA OF UPPER DIVERGENCE. THUS, WILL CONTINUE WITH
50-60 POP DURING THIS TIME FRAME AS RAIN CHCS TAPER TO SLIGHT CHC
WEST OF RIC. GIVEN BKN/OVC SKY COVER AND MEAGER INSTABILITY, HAVE
HELD THUNDER OUT OF THE FORECAST FOR NOW. GIVEN CONTINUED
CLOUDINESS, HIGHS REMAIN COOL FOR LATE APRIL...GENERALLY IN THE
UPR 60S TO NR 70, ALTHOUGH AGAIN LOCALLY COOLER ALONG IMMEDIATE
COASTLINES IN ONSHORE FLOW.

THE MID-LEVEL TROUGH AXIS PIVOTS OFF THE COAST LATE MONDAY NIGHT
AND TUESDAY WITH THE ASSOCIATED FLOW BECOMING NW (ALBEIT WEAK).
HIGH PRESSURE REMAINS TO THE NORTHEAST...AND A WEAK REMNANT LOW
LINGERS OFF THE COAST. THIS WILL ALLOW ONSHORE FLOW TO
PERSIST...WHICH SHOULD MAINTAIN CLOUD COVER ALONG WITH SLIGHT
CHANCE/LOW END CHANCE POPS DURING THIS TIME PERIOD.

HIGHS MONDAY SHOULD BE IN THE LOW/MID 60S DUE TO CLOUD COVER AND
SHOWERS. LOWS MONDAY MORNING SHOULD BE IN THE 50S. HIGHS TUESDAY ARE
FORECAST TO RANGE FROM THE MID 60S TO AROUND 70...WHICH IS BELOW
STATISTICAL GUIDANCE DUE TO EXPECTED CLOUD COVER.

TUESDAY/WEDNESDAY...
MID/UPPER LEVEL FLOW FLATTENS OUT/BECOMES QUASI-ZONAL ON TUESDAY.
THE RESULTANT MODEST DRYING ALOFT SHOULD RESULT IN A FAR DRIER DAY
ON TUESDAY. HOWEVER, STILL CANNOT TOTALLY REMOVE POPS WITH
LINGERING MOISTURE PRESENT IN LOW LEVELS PER MODEL CROSS SECTIONS.
THUS, WL RETAIN A 20-30 POP FOR SOME DIURNALLY DRIVEN SHRAS
TUESDAY AFTN/ERY EVE. FOR TEMPERATURES, FORECAST MAXIMA JUST A BIT
BELOW GUIDANCE GIVEN CONTINUED CLOUD COVER, WITH TEMPS INTO THE
LOW/MID 70S EXPECTED. EARLY MORNING LOWS GENERALLY IN THE MID TO
UPPER 50S.

DRIER ON WEDNESDAY COURTESY OF BUILDING MID-UPR RIDGING ALOFT
(COURTESY OF DEVELOPING UPPER TROUGH UPSTREAM ACROSS THE
INTERMOUNTAIN WEST). GIVEN CONTINUED MOIST LLVLS W/ONSHORE FLOW,
WL RETAIN A LOW POP FOR NOW. OTHERWISE, LOOK FOR HIGHS IN THE UPR
60S TO LOW 70S UNDER A PARTLY TO MOSTLY CLOUDY SKY.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
LONG TERM PERIOD WILL BE CHARACTERIZED BY A STAGNANT BLOCKING
PATTERN WITH AN UPR-LVL RIDGE STRETCHED ALONG THE ERN SEABOARD. AT
THE SFC...HI PRES WILL PERSIST OVER THE MID ATLANTIC OR JUST
OFFSHORE LEADING TO LGT ONSHORE FLOW AND GENLY DRY CONDS. ADJUSTED
ANY CHC POPS DOWN TO SLGT CHC WITH UPR-LVL CUTOFF LO REMAINING WELL
OFFSHORE. OVERALL...STILL FAVORING THE SLIGHTLY SLOWER ECMWF GUIDANCE
WRT THE DEVELOPING CUTOFF LO OVER THE CENTRAL CONUS AS MODELS TEND
TO BREAK DOWN BLOCKING PATTERNS TOO SOON/PROGRESS CUTOFF LOWS TOO
QUICKLY. KEPT POPS CAPPED AT 20-30% OVER THE WEEKEND DUE TO ISSUES
WITH PRECIP TIMING WITH THE APPROACHING LO. AS FOR TEMPS...HIGHS AVG
IN THE UPR 60S/LWR 70S WITH LO TEMPS IN THE UPR 40S/LWR 50S.

&&

.AVIATION /20Z SUNDAY THROUGH FRIDAY/...
MID-LEVEL CLOUDS WILL CONTINUE TO THICKEN AND LOWER FROM W TO E
TODAY. KRIC MAY SEE A SHOWER THROUGH 21Z BUT DO NOT EXPECT PCPN TO
REACH THE OTHER TAF SITES UNTIL AFTER SUNSET DUE TO LOW LEVEL DRY
AIR. THE SLOW MOVING SYSTEM WILL BRING AN INCREASING CHC OF MVFR/IFR
CONDS AND WIDESPREAD RAIN BY LATE THIS EVENING THROUGH EARLY TUESDAY
WITH IMPROVING CONDS DURING THE DAY TUESDAY.

CONFIDENCE BEYOND TUESDAY IS LOW DUE TO FORECAST MODELS DEPICTING
THE POSSIBILITY FOR SHRA DEVELOPMENT. CURRENT FORECASTS HAVE
MAINLY VFR AND ONLY SLGT CHC FOR PCPN WEDNESDAY AND THURSDAY DUE
TO UNCERTAINTY IN TIMING AND LOCATION OF SHOWER DEVELOPMENT.

&&

.MARINE...
SFC HIGH PRESSURE WILL REMAIN STATIONARY OFF THE MID-ATLANTIC COAST
THIS EVENING LEADING TO ONSHORE FLOW AROUND 10 KT. WAVES OVER THE
BAY GENERALLY 2 FT AND SEAS OVER COASTAL WATERS 3-4 FT. LOW PRESSURE
MOVES THRU THE OHIO VALLEY TONIGHT WITH SOUTHERLY WINDS INCREASING
TO 10-15 KT OVER THE WATERS. THE LOW WEAKENS AS IT APPROACHES THE
WATERS MONDAY. HOWEVER...A TIGHT GRADIENT OVER THE WATERS WITH
STRONG HIGH PRESSURE STILL OFFSHORE WILL ALLOW FOR 15-20 KT
SOUTHERLY WINDS OVER THE BAY AND 20-25 KT OVER THE COASTAL WATERS
WITH SEAS BUILDING TO 5-6 FT. SCA`S REMAIN IN PLACE FOR ALL THE
COASTAL WATERS BEGINNING 6-10 AM MONDAY AND CONTINUING THROUGH
MONDAY NIGHT AND HAVE BEEN RAISED FOR ALL BAY ZONES INCLUDING THE
CURRITUCK SOUND STARTING 7 AM THROUGH 7 PM. SMALL CRAFT CONDITIONS
WILL COME DOWN ON THE BAY/SOUND AS THE PRESSURE GRADIENT BEGINS TO
RELAX MON EVENING. SFC HIGH PRESSURE REMAINS LOCKED IN PLACE OVER
THE NEW ENGLAND COAST THRU THE COMING WEEK ALLOWING FOR PERSISTENT
E-NE WINDS OVER THE LOCAL WATERS. ALTHOUGH WINDS WILL LIKELY REMAIN
SUB-SCA DURING THIS TIME...SEAS WILL REMAIN AOA 5 FT SO SCA`S WILL
LIKELY CONTINUE FOR THE ENTIRE WEEK.

&&

.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 10 AM TO 7 PM EDT MONDAY FOR
     ANZ630>634.
     SMALL CRAFT ADVISORY FROM 10 AM MONDAY TO 6 AM EDT TUESDAY FOR
     ANZ650-652-654.
     SMALL CRAFT ADVISORY FROM 6 AM MONDAY TO 6 AM EDT TUESDAY FOR
     ANZ656-658.

&&

$$
SYNOPSIS...MAM
NEAR TERM...MAM
SHORT TERM...AJZ/MAM
LONG TERM...MAS
AVIATION...JDM/DAP
MARINE...JDM/DAP







AREA FORECAST DISCUSSION

NWS WAKEFIELD VA

 357 PM EDT SUN APR 28 2013

.SYNOPSIS...
HIGH PRESSURE WILL REMAIN JUST OFFSHORE THROUGH MONDAY...AS LOW
PRESSURE LIFTS NORTHEAST FROM THE MISSISSIPPI VALLEY INTO THE OHIO
VALLEY. THIS AREA OF LOW PRESSURE WILL VERY SLOWLY TRACK ACROSS
THE MID ATLANTIC REGION TONIGHT THROUGH MONDAY NIGHT. LOW PRESSURE
LINGERS OFF THE CAROLINA COAST THROUGH MIDWEEK AS HIGH PRESSURE
REMAINS ANCHORED OVER THE CANADIAN MARITIMES.

&&

.NEAR TERM /THROUGH TONIGHT/...
THE LATEST WX ANALYSIS SHOWS ~1028MB SURFACE HIGH WHICH REMAINS
ORIENTED JUST OFF THE MID-ATLANTIC/NORTHEAST COAST. TO THE WEST,
WEAKENING MID/UPPER LEVEL LOW PRESSURE HAS WEAKENED TO AN
OPEN WAVE AS IT CONTINUES TO SLOWLY LIFT NE FROM THE CHICAGOLAND
AREA INTO THE UPPER GREAT LAKES. AREA OF LIGHT RAIN HAS INCREASED
ALONG AND AHEAD OF SLOW MOVING COLD FRONT DRAPED ACROSS THE OH/TN
VLY. CLOSER TO HOME, CLOUD COVER HAS CONTINUED TO THICKEN AND
LOWER AS EXPECTED EARLY THIS AFTN AS EXPECTED, ESPECIALLY ACROSS
THE PIEDMONT. HOWEVER...DESPITE INCREASING CLDS THIS AFTN, THE
INFLUENCE OF THE HIGH ALONG THE EASTERN SEABOARD WILL RESULT IN
PERSISTENT LOW-LEVEL DRY AIR (BELOW 800MB) OVER THE LOCAL AREA PER
FORECAST BUFR SOUNDINGS. GIVEN THIS...WILL DOWNPLAY WIDESPREAD
POPS W/THE USE OF A GENERAL PERSISTENCE FORECAST (WHICH JIVES WELL
WITH RUC DEPICTION OF POPS) FOR THE NEXT FEW HOURS. RAIN CHANCES
HV BEEN BUMPED INTO LKLY RANGE FOR FAR WESTERN PIEDMONT, WITH
SLIGHT CHC/LOW CHANCE POPS FARTHER EAST FOR THE REST OF THE
AFTERNOON.

THERE IS VERY LITTLE CHANGE IN THE LOW-LEVEL THERMAL PROFILE FROM
YESTERDAY,SO THE MAIN INFLUENCE ON HIGH TEMPERATURES WILL BE
INCREASING CLOUD COVER. THIS HAS HELD MAXIMA LARGELY IN THE
MID/UPPER 60S. EAST OF I-95...TEMPERATURES HV REACHED TO ~70/LOW
70S, AND HAVE EVEN DROPPED OFF SLIGHTLY AS CLDS HV BUILT EAST OVER
THE PAST FEW HRS.

RAIN CHANCES GRADUALLY INCREASE TONIGHT AS UPPER TROUGH
APPROACHES THROUGH LATE TONIGHT. INCREASING SYNOPTIC LIFT WILL
SHUNT A STEADY STREAM OF MOISTURE ADVECTION ACROSS THE AREA
TONIGHT, WHICH DEVELOPS ALONG THE EAST COAST. THIS INCREASE IN PW
IS THE RESULT OF THE APPROACHING TROUGH TO THE WEST AND
AFOREMENTIONED QUASI- STATIONARY HIGH TO THE EAST. THIS MOISTURE
TRANSPORT (GOOD MODEL AGREEMENT IN INCREASING PW VALUES TO ~1.3IN)
WILL OFFSET WEAKENING DYNAMICS AND YIELD A PERIOD OF LIGHT TO
MODERATE PCPN LATE TONIGHT INTO MONDAY MORNING. HAVE
CONTINUED/INCREASED POPS INTO CATEGORICAL RANGE WEST OF THE BAY
AFTER 00Z/8P EDT, WITH RAIN CHANCES INCREASING OVER THE EASTERN
SHORE AFTER 06Z/2AM MONDAY.

FOR LOWS, CLOUDY SKY AND MOISTENING LLVLS SHOULD KEEP HIGHS MILD.
EARLY MORNING LOWS IN THE MID 50S TO NR 60.


&&

.SHORT TERM /MONDAY THROUGH WEDNESDAY/...

BY MONDAY...THE TROUGH AXIS VERY SLOWLY APPROACHES THE WESTERN
PORTION OF THE AREA MONDAY MORNING. STEADY STRATIFORM RAIN TAPERS
TO SOME SHRAS WEST OF I-95 MONDAY AFTN AS THE BEST MOISTURE
TRANSPORT GRADUALLY SHIFTS TOWARD THE COAST. 12Z GFS/NAM EACH
SHUNT OMEGA MAX FROM THE THE EASTERN CAROLINAS ACROSS ATLANTIC
COASTAL AREAS MONDAY AFTERNOON AND EVENING...WHICH MESHES WELL
WITH PROGGED AREA OF UPPER DIVERGENCE. THUS, WILL CONTINUE WITH
50-60 POP DURING THIS TIME FRAME AS RAIN CHCS TAPER TO SLIGHT CHC
WEST OF RIC. GIVEN BKN/OVC SKY COVER AND MEAGER INSTABILITY, HAVE
HELD THUNDER OUT OF THE FORECAST FOR NOW. GIVEN CONTINUED
CLOUDINESS, HIGHS REMAIN COOL FOR LATE APRIL...GENERALLY IN THE
UPR 60S TO NR 70, ALTHOUGH AGAIN LOCALLY COOLER ALONG IMMEDIATE
COASTLINES IN ONSHORE FLOW.

THE MID-LEVEL TROUGH AXIS PIVOTS OFF THE COAST LATE MONDAY NIGHT
AND TUESDAY WITH THE ASSOCIATED FLOW BECOMING NW (ALBEIT WEAK).
HIGH PRESSURE REMAINS TO THE NORTHEAST...AND A WEAK REMNANT LOW
LINGERS OFF THE COAST. THIS WILL ALLOW ONSHORE FLOW TO
PERSIST...WHICH SHOULD MAINTAIN CLOUD COVER ALONG WITH SLIGHT
CHANCE/LOW END CHANCE POPS DURING THIS TIME PERIOD.

HIGHS MONDAY SHOULD BE IN THE LOW/MID 60S DUE TO CLOUD COVER AND
SHOWERS. LOWS MONDAY MORNING SHOULD BE IN THE 50S. HIGHS TUESDAY ARE
FORECAST TO RANGE FROM THE MID 60S TO AROUND 70...WHICH IS BELOW
STATISTICAL GUIDANCE DUE TO EXPECTED CLOUD COVER.

TUESDAY/WEDNESDAY...
MID/UPPER LEVEL FLOW FLATTENS OUT/BECOMES QUASI-ZONAL ON TUESDAY.
THE RESULTANT MODEST DRYING ALOFT SHOULD RESULT IN A FAR DRIER DAY
ON TUESDAY. HOWEVER, STILL CANNOT TOTALLY REMOVE POPS WITH
LINGERING MOISTURE PRESENT IN LOW LEVELS PER MODEL CROSS SECTIONS.
THUS, WL RETAIN A 20-30 POP FOR SOME DIURNALLY DRIVEN SHRAS
TUESDAY AFTN/ERY EVE. FOR TEMPERATURES, FORECAST MAXIMA JUST A BIT
BELOW GUIDANCE GIVEN CONTINUED CLOUD COVER, WITH TEMPS INTO THE
LOW/MID 70S EXPECTED. EARLY MORNING LOWS GENERALLY IN THE MID TO
UPPER 50S.

DRIER ON WEDNESDAY COURTESY OF BUILDING MID-UPR RIDGING ALOFT
(COURTESY OF DEVELOPING UPPER TROUGH UPSTREAM ACROSS THE
INTERMOUNTAIN WEST). GIVEN CONTINUED MOIST LLVLS W/ONSHORE FLOW,
WL RETAIN A LOW POP FOR NOW. OTHERWISE, LOOK FOR HIGHS IN THE UPR
60S TO LOW 70S UNDER A PARTLY TO MOSTLY CLOUDY SKY.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
LONG TERM PERIOD WILL BE CHARACTERIZED BY A STAGNANT BLOCKING
PATTERN WITH AN UPR-LVL RIDGE STRETCHED ALONG THE ERN SEABOARD. AT
THE SFC...HI PRES WILL PERSIST OVER THE MID ATLANTIC OR JUST
OFFSHORE LEADING TO LGT ONSHORE FLOW AND GENLY DRY CONDS. ADJUSTED
ANY CHC POPS DOWN TO SLGT CHC WITH UPR-LVL CUTOFF LO REMAINING WELL
OFFSHORE. OVERALL...STILL FAVORING THE SLIGHTLY SLOWER ECMWF GUIDANCE
WRT THE DEVELOPING CUTOFF LO OVER THE CENTRAL CONUS AS MODELS TEND
TO BREAK DOWN BLOCKING PATTERNS TOO SOON/PROGRESS CUTOFF LOWS TOO
QUICKLY. KEPT POPS CAPPED AT 20-30% OVER THE WEEKEND DUE TO ISSUES
WITH PRECIP TIMING WITH THE APPROACHING LO. AS FOR TEMPS...HIGHS AVG
IN THE UPR 60S/LWR 70S WITH LO TEMPS IN THE UPR 40S/LWR 50S.

&&

.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
MID-LEVEL CLOUDS WILL CONTINUE TO THICKEN AND LOWER FROM W TO E
TODAY. KRIC MAY SEE A SHOWER THROUGH 21Z BUT DO NOT EXPECT PCPN TO
REACH THE OTHER TAF SITES UNTIL AFTER SUNSET DUE TO LOW LEVEL DRY
AIR. THE SLOW MOVING SYSTEM WILL BRING AN INCREASING CHC OF MVFR/IFR
CONDS AND WIDESPREAD RAIN BY LATE THIS EVENING THROUGH EARLY TUESDAY
WITH IMPROVING CONDS DURING THE DAY TUESDAY.

CONFIDENCE BEYOND TUESDAY IS LOW DUE TO FORECAST MODELS DEPICTING
THE POSSIBILITY FOR SHRA DEVELOPMENT. CURRENT FORECASTS HAVE
MAINLY VFR AND ONLY SLGT CHC FOR PCPN WEDNESDAY AND THURSDAY DUE
TO UNCERTAINTY IN TIMING AND LOCATION OF SHOWER DEVELOPMENT.

&&

.MARINE...
SFC HIGH PRESSURE WILL REMAIN STATIONARY OFF THE MID-ATLANTIC COAST
TODAY LEADING TO LIGHT ONSHORE FLOW. WAVES OVER THE BAY 1-2 FT AND
SEAS OVER COASTAL WATERS 3-4 FT. LOW PRESSURE MOVES THRU THE OHIO
VALLEY TONIGHT WITH SERLY WINDS INCREASING TO 10-15 KT OVER THE
WATERS. THE LOW WEAKENS AS IT APPROACHES THE WATERS MONDAY.
HOWEVER...A TIGHT GRADIENT OVER THE WATERS WITH STRONG HIGH PRESSURE
STILL OFFSHORE WILL ALLOW FOR 10-15 KT SERLY WINDS OVER THE BAY AND
15-20 KT OVER THE COASTAL WATERS WITH SEAS BUILDING TO 5-6 FT. HAVE
HOISTED SCA`S FOR ALL THE COASTAL WATERS BEGINNING 6-10 AM MONDAY
AND CONTINUING THROUGH MONDAY NIGHT. SFC HIGH PRESSURE REMAINS
LOCKED IN PLACE OVER THE NEW ENGLAND COAST THRU THE COMING WEEK
ALLOWING FOR PERSISTENT E-NE WINDS OVER THE LOCAL WATERS. ALTHOUGH
WINDS WILL LIKELY REMAIN SUB-SCA DURING THIS TIME...SEAS WILL REMAIN
AOA 5 FT SO SCA`S WILL LIKELY CONTINUE FOR THE ENTIRE WEEK.

&&

.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 10 AM MONDAY TO 6 AM EDT TUESDAY FOR
     ANZ650-652-654.
     SMALL CRAFT ADVISORY FROM 6 AM MONDAY TO 6 AM EDT TUESDAY FOR
     ANZ656-658.

&&

$$
SYNOPSIS...MAM
NEAR TERM...MAM
SHORT TERM...AJZ/MAM
LONG TERM...MAS
AVIATION...JDM/DAP
MARINE...JDM










AREA FORECAST DISCUSSION

NWS WAKEFIELD VA

 158 PM EDT SUN APR 28 2013

.SYNOPSIS...
HIGH PRESSURE WILL REMAIN JUST OFFSHORE...AS LOW PRESSURE LIFTS
NORTHEAST FROM THE MISSISSIPPI VALLEY INTO THE OHIO VALLEY. THIS
AREA OF LOW PRESSURE WILL VERY SLOWLY TRACK ACROSS THE MID
ATLANTIC REGION TONIGHT THROUGH MONDAY NIGHT. LOW PRESSURE LINGERS
OFF THE CAROLINA COAST THROUGH MIDWEEK AS HIGH PRESSURE REMAINS
ANCHORED OVER THE CANADIAN MARITIMES.

&&

.NEAR TERM /THROUGH TONIGHT/...
THE LATEST WX ANALYSIS SHOWS ~1028MB SURFACE HIGH WHICH REMAINS
ORIENTED JUST OFF THE MID-ATLANTIC/NORTHEAST COAST. TO THE WEST,
WEAKENING MID/UPPER LEVEL LOW PRESSURE HAS WEAKENED TO AN
OPEN WAVE AS IT CONTINUES TO SLOWLY LIFT NE FROM THE CHICAGOLAND
AREA INTO THE UPPER GREAT LAKES. AREA OF LIGHT RAIN HAS INCREASED
ALONG AND AHEAD OF SLOW MOVING COLD FRONT DRAPED ACROSS THE OH/TN
VLY. CLOSER TO HOME, CLOUD COVER HAS CONTINUED TO THICKEN AND
LOWER AS EXPECTED EARLY THIS AFTN AS EXPECTED, ESPECIALLY ACROSS
THE PIEDMONT. HOWEVER...DESPITE INCREASING CLDS THIS AFTN, THE
INFLUENCE OF THE HIGH ALONG THE EASTERN SEABOARD WILL RESULT IN
PERSISTENT LOW-LEVEL DRY AIR (BELOW 800MB) OVER THE LOCAL AREA PER
FORECAST BUFR SOUNDINGS. GIVEN THIS...WILL DOWNPLAY WIDESPREAD
POPS W/THE USE OF A GENERAL PERSISTENCE FORECAST (WHICH JIVES WELL
WITH RUC DEPICTION OF POPS) FOR THE NEXT FEW HOURS. RAIN CHANCES
HV BEEN BUMPED INTO LKLY RANGE FOR FAR WESTERN PIEDMONT, WITH
SLIGHT CHC/LOW CHANCE POPS FARTHER EAST FOR THE REST OF THE
AFTERNOON.

THERE IS VERY LITTLE CHANGE IN THE LOW-LEVEL THERMAL PROFILE FROM
YESTERDAY,SO THE MAIN INFLUENCE ON HIGH TEMPERATURES WILL BE
INCREASING CLOUD COVER. THIS SHOULD HOLD MAXIMA IN THE MID/UPPER
60S WEST OF I-95 WHERE CLOUD COVER WILL BE MOST OPAQUE THIS AFTN.
EAST OF I-95...TEMPERATURES IN ~70/LOW 70S ARE EXPECTED.
HOWEVER...READINGS WILL BE LOCALLY COOLER ALONG THE IMMEDIATE
COASTLINES WITH ONSHORE FLOW.

&&

.SHORT TERM /MONDAY THROUGH TUESDAY/...
THE PRIMARY SHORTWAVE TROUGH LIFTS TOWARD THE GREAT LAKES TONIGHT
WITH THE TRAILING AXIS EXTENDING OVER THE APPALACHIANS. THE SURFACE
LOW GRADUALLY LOSES ITS DISTINCTION. BY MONDAY...THE TROUGH AXIS
VERY SLOWLY APPROACHES THE WESTERN PORTION OF THE AREA. A STEADY
STREAM OF MOISTURE ADVECTION DEVELOPS ALONG THE EAST COAST AS A
RESULT OF THE APPROACHING TROUGH TO THE WEST AND A QUASI-STATIONARY
HIGH TO THE EAST. THIS MOISTURE TRANSPORT (PW VALUES RISING TO
~1.3IN) OFFSETS WEAKENING DYNAMICS AND AS A RESULT POPS HAVE BEEN
INCREASED TO CATEGORICAL FOR ALL BUT THE EASTERN SHORE AFTER 06Z
MONDAY AND THEN INTO THE EASTERN SHORE MONDAY MORNING (AFTER 12Z).
THE BEST MOISTURE TRANSPORT GRADUALLY SHIFTS TOWARD THE COAST DURING
THE AFTERNOON AND EVENING HOURS AND HENCE POPS WILL SLOWLY DIMINISH
FOR WESTERN AREAS. CONFIDENCE ON QPF REMAINS RATHER LOW AS IT WILL
ULTIMATELY BE DICTATED BY HOW MUCH SHORTWAVE DYNAMICS REMAIN. 00Z
GFS/NAM EACH INDICATE A MAX IN OMEGA OVER THE EASTERN CAROLINAS
MONDAY...WHICH HAS THE POTENTIAL TO LIMIT THE AMOUNT OF MOISTURE
TRANSPORTED INTO THE MID-ATLANTIC REGION.

THE MID-LEVEL TROUGH AXIS MOVES OFF THE COAST LATE MONDAY NIGHT AND
TUESDAY WITH THE ASSOCIATED FLOW BECOMING NW (ALBEIT WEAK). HIGH
PRESSURE REMAINS TO THE NORTHEAST...AND A WEAK REMNANT LOW LINGERS
OFF THE COAST. THIS WILL ALLOW ONSHORE FLOW TO PERSIST...WHICH
SHOULD MAINTAIN CLOUD COVER ALONG WITH SLIGHT CHANCE/LOW END CHANCE
POPS DURING THIS TIME PERIOD.

HIGHS MONDAY SHOULD BE IN THE LOW/MID 60S DUE TO CLOUD COVER AND
SHOWERS. LOWS MONDAY MORNING SHOULD BE IN THE 50S. HIGHS TUESDAY ARE
FORECAST TO RANGE FROM THE MID 60S TO AROUND 70...WHICH IS BELOW
STATISTICAL GUIDANCE DUE TO EXPECTED CLOUD COVER.

&&

.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
LONG TERM PERIOD WILL BE CHARACTERIZED BY PERIODS OF UNSETTLED WX
AND NEAR NORMAL TEMPS. LO CONFIDENCE ON TIMING OF PRECIP DUE TO A
DEVELOPING BLOCKING PATTERN. DID FAVOR THE SLOWER GUIDANCE WRT
APPROACHING CUTOFF LO (ECMWF) AS MODELS TEND TO BREAK DOWN BLOCKING
PATTERNS TOO SOON/PROGRESS CUTOFF LOWS TOO QUICKLY. OVERALL...HI
AMPLITUDE UPR-LVL RIDGE WILL PERSIST OVER THE FAR EASTERN CONUS
THRU THE LONG TERM PERIOD. MID-LVL VORT MAXIMA SWINGING AROUND AN
OFFSHORE CUTOFF LO AND ASSOCIATED MOISTURE SURGES WILL LEAD TO CHCS
FOR RAIN AT TIMES THRU THE PERIOD. KEPT POPS CAPPED AT 20-30% DUE TO
ISSUES WITH PRECIP TIMING AND THE ECMWF BEING SLOWER WITH THE CUTOFF
LO. HIGH TEMPS AVG IN THE UPR 60S/LWR 70S WITH LO TEMPS IN THE UPR
40S/LWR 50S.

&&

.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
MID-LEVEL CLOUDS WILL CONTINUE TO THICKEN AND LOWER FROM W TO E
TODAY. KRIC MAY SEE A SHOWER THROUGH 21Z BUT DO NOT EXPECT PCPN TO
REACH THE OTHER TAF SITES UNTIL AFTER SUNSET DUE TO LOW LEVEL DRY
AIR. THE SLOW MOVING SYSTEM WILL BRING AN INCREASING CHC OF MVFR/IFR
CONDS AND WIDESPREAD RAIN BY LATE THIS EVENING THROUGH EARLY TUESDAY
WITH IMPROVING CONDS DURING THE DAY TUESDAY.

CONFIDENCE BEYOND TUESDAY IS LOW DUE TO FORECAST MODELS DEPICTING
THE POSSIBILITY FOR SHRA DEVELOPMENT. CURRENT FORECASTS HAVE
MAINLY VFR AND ONLY SLGT CHC FOR PCPN WEDNESDAY AND THURSDAY DUE
TO UNCERTAINTY IN TIMING AND LOCATION OF SHOWER DEVELOPMENT.

&&

.MARINE...
SFC HIGH PRESSURE WILL REMAIN STATIONARY OFF THE MID-ATLANTIC COAST
TODAY LEADING TO LIGHT ONSHORE FLOW. WAVES OVER THE BAY 1-2 FT AND
SEAS OVER COASTAL WATERS 3-4 FT. LOW PRESSURE MOVES THRU THE OHIO
VALLEY TONIGHT WITH SERLY WINDS INCREASING TO 10-15 KT OVER THE
WATERS. THE LOW WEAKENS AS IT APPROACHES THE WATERS MONDAY.
HOWEVER...A TIGHT GRADIENT OVER THE WATERS WITH STRONG HIGH PRESSURE
STILL OFFSHORE WILL ALLOW FOR 10-15 KT SERLY WINDS OVER THE BAY AND
15-20 KT OVER THE COASTAL WATERS WITH SEAS BUILDING TO 5-6 FT. HAVE
HOISTED SCA`S FOR ALL THE COASTAL WATERS BEGINNING 6-10 AM MONDAY
AND CONTINUING THROUGH MONDAY NIGHT. SFC HIGH PRESSURE REMAINS
LOCKED IN PLACE OVER THE NEW ENGLAND COAST THRU THE COMING WEEK
ALLOWING FOR PERSISTENT E-NE WINDS OVER THE LOCAL WATERS. ALTHOUGH
WINDS WILL LIKELY REMAIN SUB-SCA DURING THIS TIME...SEAS WILL REMAIN
AOA 5 FT SO SCA`S WILL LIKELY CONTINUE FOR THE ENTIRE WEEK.

&&

.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 10 AM MONDAY TO 6 AM EDT TUESDAY FOR
     ANZ650-652-654.
     SMALL CRAFT ADVISORY FROM 6 AM MONDAY TO 6 AM EDT TUESDAY FOR
     ANZ656-658.

&&

$$
SYNOPSIS...AJZ
NEAR TERM...AJZ/MAM
SHORT TERM...AJZ
LONG TERM...MAS
AVIATION...JDM/DAP
MARINE...JDM









AREA FORECAST DISCUSSION

NWS WAKEFIELD VA

 147 PM EDT SUN APR 28 2013

.SYNOPSIS...
HIGH PRESSURE WILL REMAIN JUST OFFSHORE...AS LOW PRESSURE LIFTS
NORTHEAST FROM THE MISSISSIPPI VALLEY INTO THE OHIO VALLEY. THIS
AREA OF LOW PRESSURE WILL VERY SLOWLY TRACK ACROSS THE MID
ATLANTIC REGION TONIGHT THROUGH MONDAY NIGHT. LOW PRESSURE LINGERS
OFF THE CAROLINA COAST THROUGH MIDWEEK AS HIGH PRESSURE REMAINS
ANCHORED OVER THE CANADIAN MARITIMES.

&&

.NEAR TERM /THROUGH TONIGHT/...
THE LATEST WX ANALYSIS SHOWS ~1028MB SURFACE HIGH WHICH REMAINS
ORIENTED JUST OFF THE MID-ATLANTIC/NORTHEAST COAST. TO THE WEST,
WEAKENING MID/UPPER LEVEL LOW PRESSURE HAS WEAKENED TO AN
OPEN WAVE AS IT CONTINUES TO SLOWLY LIFT NE FROM THE CHICAGOLAND
AREA INTO THE UPPER GREAT LAKES. AREA OF LIGHT RAIN HAS INCREASED
ALONG AND AHEAD OF SLOW MOVING COLD FRONT DRAPED ACROSS THE OH/TN
VLY. CLOSER TO HOME, CLOUD COVER HAS CONTINUED TO THICKEN AND
LOWER AS EXPECTED EARLY THIS AFTN AS EXPECTED, ESPECIALLY ACROSS
THE PIEDMONT. HOWEVER...DESPITE INCREASING CLDS THIS AFTN, THE
INFLUENCE OF THE HIGH ALONG THE EASTERN SEABOARD WILL RESULT IN
PERSISTENT LOW-LEVEL DRY AIR (BELOW 800MB) OVER THE LOCAL AREA PER
FORECAST BUFR SOUNDINGS. GIVEN THIS...WILL DOWNPLAY WIDESPREAD
POPS W/THE USE OF A GENERAL PERSISTENCE FORECAST (WHICH JIVES WELL
WITH RUC DEPICTION OF POPS) FOR THE NEXT FEW HOURS. RAIN CHANCES
HV BEEN BUMPED INTO LKLY RANGE FOR FAR WESTERN PIEDMONT, WITH
SLIGHT CHC/LOW CHANCE POPS FARTHER EAST FOR THE REST OF THE
AFTERNOON.

THERE IS VERY LITTLE CHANGE IN THE LOW-LEVEL THERMAL PROFILE FROM
YESTERDAY,SO THE MAIN INFLUENCE ON HIGH TEMPERATURES WILL BE
INCREASING CLOUD COVER. THIS SHOULD HOLD MAXIMA IN THE MID/UPPER
60S WEST OF I-95 WHERE CLOUD COVER WILL BE MOST OPAQUE THIS AFTN.
EAST OF I-95...TEMPERATURES IN ~70/LOW 70S ARE EXPECTED.
HOWEVER...READINGS WILL BE LOCALLY COOLER ALONG THE IMMEDIATE
COASTLINES WITH ONSHORE FLOW.

&&

.SHORT TERM /MONDAY THROUGH TUESDAY/...
THE PRIMARY SHORTWAVE TROUGH LIFTS TOWARD THE GREAT LAKES TONIGHT
WITH THE TRAILING AXIS EXTENDING OVER THE APPALACHIANS. THE SURFACE
LOW GRADUALLY LOSES ITS DISTINCTION. BY MONDAY...THE TROUGH AXIS
VERY SLOWLY APPROACHES THE WESTERN PORTION OF THE AREA. A STEADY
STREAM OF MOISTURE ADVECTION DEVELOPS ALONG THE EAST COAST AS A
RESULT OF THE APPROACHING TROUGH TO THE WEST AND A QUASI-STATIONARY
HIGH TO THE EAST. THIS MOISTURE TRANSPORT (PW VALUES RISING TO
~1.3IN) OFFSETS WEAKENING DYNAMICS AND AS A RESULT POPS HAVE BEEN
INCREASED TO CATEGORICAL FOR ALL BUT THE EASTERN SHORE AFTER 06Z
MONDAY AND THEN INTO THE EASTERN SHORE MONDAY MORNING (AFTER 12Z).
THE BEST MOISTURE TRANSPORT GRADUALLY SHIFTS TOWARD THE COAST DURING
THE AFTERNOON AND EVENING HOURS AND HENCE POPS WILL SLOWLY DIMINISH
FOR WESTERN AREAS. CONFIDENCE ON QPF REMAINS RATHER LOW AS IT WILL
ULTIMATELY BE DICTATED BY HOW MUCH SHORTWAVE DYNAMICS REMAIN. 00Z
GFS/NAM EACH INDICATE A MAX IN OMEGA OVER THE EASTERN CAROLINAS
MONDAY...WHICH HAS THE POTENTIAL TO LIMIT THE AMOUNT OF MOISTURE
TRANSPORTED INTO THE MID-ATLANTIC REGION.

THE MID-LEVEL TROUGH AXIS MOVES OFF THE COAST LATE MONDAY NIGHT AND
TUESDAY WITH THE ASSOCIATED FLOW BECOMING NW (ALBEIT WEAK). HIGH
PRESSURE REMAINS TO THE NORTHEAST...AND A WEAK REMNANT LOW LINGERS
OFF THE COAST. THIS WILL ALLOW ONSHORE FLOW TO PERSIST...WHICH
SHOULD MAINTAIN CLOUD COVER ALONG WITH SLIGHT CHANCE/LOW END CHANCE
POPS DURING THIS TIME PERIOD.

HIGHS MONDAY SHOULD BE IN THE LOW/MID 60S DUE TO CLOUD COVER AND
SHOWERS. LOWS MONDAY MORNING SHOULD BE IN THE 50S. HIGHS TUESDAY ARE
FORECAST TO RANGE FROM THE MID 60S TO AROUND 70...WHICH IS BELOW
STATISTICAL GUIDANCE DUE TO EXPECTED CLOUD COVER.

&&

.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
LONG TERM PERIOD WILL BE CHARACTERIZED BY PERIODS OF UNSETTLED WX
AND NEAR NORMAL TEMPS. LO CONFIDENCE ON TIMING OF PRECIP DUE TO A
DEVELOPING BLOCKING PATTERN. DID FAVOR THE SLOWER GUIDANCE WRT
APPROACHING CUTOFF LO (ECMWF) AS MODELS TEND TO BREAK DOWN BLOCKING
PATTERNS TOO SOON/PROGRESS CUTOFF LOWS TOO QUICKLY. OVERALL...HI
AMPLITUDE UPR-LVL RIDGE WILL PERSIST OVER THE FAR EASTERN CONUS
THRU THE LONG TERM PERIOD. MID-LVL VORT MAXIMA SWINGING AROUND AN
OFFSHORE CUTOFF LO AND ASSOCIATED MOISTURE SURGES WILL LEAD TO CHCS
FOR RAIN AT TIMES THRU THE PERIOD. KEPT POPS CAPPED AT 20-30% DUE TO
ISSUES WITH PRECIP TIMING AND THE ECMWF BEING SLOWER WITH THE CUTOFF
LO. HIGH TEMPS AVG IN THE UPR 60S/LWR 70S WITH LO TEMPS IN THE UPR
40S/LWR 50S.

&&

.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
VFR CONDS ARE EXPECTED THROUGH AT LEAST 00Z MONDAY. MID-LEVEL
CLOUDS WILL THICKEN AND LOWER FROM W TO E TODAY AND PCPN IS NOT
LIKELY TO REACH THE TAF SITES UNTIL AFTER SUNSET.

OUTLOOK...A SLOW MOVING SYSTEM WILL BRING AN INCREASING CHC OF
MVFR/IFR CONDS IN RAIN BY LATE THIS EVENING THROUGH EARLY
TUESDAY. CONDS BEGIN TO IMPROVE DURING THE DAY TUESDAY. CONFIDENCE
BEYOND TUESDAY IS LOW BUT CURRENT FORECASTS HAVE MAINLY VFR AND
ONLY SLGT CHC FOR PCPN WEDNESDAY AND THURSDAY.

&&

.MARINE...
SFC HIGH PRESSURE WILL REMAIN STATIONARY OFF THE MID-ATLANTIC COAST
TODAY LEADING TO LIGHT ONSHORE FLOW. WAVES OVER THE BAY 1-2 FT AND
SEAS OVER COASTAL WATERS 3-4 FT. LOW PRESSURE MOVES THRU THE OHIO
VALLEY TONIGHT WITH SERLY WINDS INCREASING TO 10-15 KT OVER THE
WATERS. THE LOW WEAKENS AS IT APPROACHES THE WATERS MONDAY.
HOWEVER...A TIGHT GRADIENT OVER THE WATERS WITH STRONG HIGH PRESSURE
STILL OFFSHORE WILL ALLOW FOR 10-15 KT SERLY WINDS OVER THE BAY AND
15-20 KT OVER THE COASTAL WATERS WITH SEAS BUILDING TO 5-6 FT. HAVE
HOISTED SCA`S FOR ALL THE COASTAL WATERS BEGINNING 6-10 AM MONDAY
AND CONTINUING THROUGH MONDAY NIGHT. SFC HIGH PRESSURE REMAINS
LOCKED IN PLACE OVER THE NEW ENGLAND COAST THRU THE COMING WEEK
ALLOWING FOR PERSISTENT E-NE WINDS OVER THE LOCAL WATERS. ALTHOUGH
WINDS WILL LIKELY REMAIN SUB-SCA DURING THIS TIME...SEAS WILL REMAIN
AOA 5 FT SO SCA`S WILL LIKELY CONTINUE FOR THE ENTIRE WEEK.

&&

.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 10 AM MONDAY TO 6 AM EDT TUESDAY FOR
     ANZ650-652-654.
     SMALL CRAFT ADVISORY FROM 6 AM MONDAY TO 6 AM EDT TUESDAY FOR
     ANZ656-658.

&&

$$
SYNOPSIS...AJZ
NEAR TERM...AJZ/MAM
SHORT TERM...AJZ
LONG TERM...MAS
AVIATION...JDM
MARINE...JDM
EQUIPMENT...










AREA FORECAST DISCUSSION

NWS DETROIT/PONTIAC MI

 116 PM EDT SUN APR 28 2013


.AVIATION...

//DISCUSSION...

MOISTURE AND RAIN SHOWERS CONTINUE TO SURGE NORTH ACROSS SOUTHEAST
MICHIGAN EARLY THIS AFTERNOON. HOWEVER WITH THE MAIN SURFACE LOW
TRACKING EAST THE MAIN AREA OF PRECIPITATION IS EXPECTED TO MAKE A
PIVOT FROM MOVING NORTH TO EXITING EAST ALONG WITH THE SURFACE LOW.
THEREFORE LITTLE IF ANY RAIN IS EXPECTED TO FALL AT MBS. HOWEVER LOW
LEVEL MOISTURE IS STILL EXPECTED TO PUSH INTO MBS...BRINGING
CONDITIONS DOWN TO IFR LIKE THE REST OF THE TAF SITES. HOWEVER WITH
LESS RAIN MBS IS EXPECTED TO BE BETTER OFF THAN THE REST OF THE TAF
SITES FURTHER SOUTH WHICH ARE EXPECTED TO DROP TO LIFR AND VLIFR
OVERNIGHT AS FRESH MOISTURE ON THE GROUND BRINGS STRATUS AND POCKETS
OF FOG DURING THE OVERNIGHT HOURS.

FOR DTW...THE STEADY SHOWER ACTIVITY IS EXPECTED TO END AROUND 00Z.
ABUNDANT LOW LEVEL MOISTURE WILL BRING A MEDIUM TO HIGH POTENTIAL
FOR VLIFR CONDITIONS THROUGHOUT TONIGHT.

//DTW THRESHOLD THREATS...

* HIGH CONFIDENCE IN CEILINGS BELOW 5000 FEET THROUGH TONIGHT.

* MEDIUM TO HIGH CONFIDENCE IN CEILINGS DOWN TO 200 FEET AFTER 00Z.

&&

.PREV DISCUSSION...ISSUED 1056 AM EDT SUN APR 28 2013

UPDATE...

RAIN SHOWERS CONTINUE TO EDGE NORTHWARD INTO SOUTHEASTERN MICHIGAN
DURING THE LATE MORNING HOURS. HOWEVER THEY ARE ENCOUNTERING QUITE
A BIT OF LOW LEVEL DRY AIR AS EVIDENCED BY THE 12Z DTX RAOB
SOUNDING. THE LOCAL HI-RES MODELS ARE CAPTURING THIS QUITE WELL
AND KEEP MUCH OF THE ACTIVITY ALONG AND SOUTH OF M-59 THROUGH THE
EARLY AFTERNOON...THEN TRANSITIONING OFF TO THE EAST AS THE LOW
TRACKS EAST THROUGH OHIO. GIVEN THE ABUNDANT DRY AIR IN PLACE
ACROSS THE NORTH AND THE PERFORMANCE OF THE LOCAL 3KM HRRR MODEL
WILL TIGHTEN UP THE POPS ACROSS THE CWA...LOWERING AMOUNTS ACROSS
THE NORTH AND RAISING THEM ACROSS THE SOUTH.

PREV DISCUSSION...ISSUED 356 AM EDT SUN APR 28 2013

SHORT TERM...TODAY AND TONIGHT

08-12Z...AN AMPLITUDE INCREASE OF THE EASTERN NORTH AMERICA LONGWAVE
RIDGE WILL BE THE FORCING MECHANISM WHICH WILL DRAW THE SOUTHERN IL
PV ANOMALY NORTHWARD INTO MICHIGAN TODAY. TWO SPIRALS OF 700-500MB
DEFORMATION WILL EMANATE NORTHWARD AWAY FROM THE PARENT VORTICITY
MAXIMUM THE FIRST OF WHICH WILL LIFT ACROSS THE MICHIGAN/OHIO
STATELINE AFTER 9Z. THIS IS ADVERTISED BY LINEAR EXTRAPOLATION FROM
RADAR MOSAIC AND TIMING OF NAM/RAP. DEFORMATION FORCING WILL BE
COASTING INTO THE STATE...WEAKENING DRAMATICALLY ACCORDING TO NWP
PROJECTIONS. FEEL GOOD ABOUT THIS GIVEN INCREASING DISTANCE FROM
VORTICITY MAXIMUM...WARMING CLOUD TOPS IN LATEST IR...AND SPOTTY
COVERAGE IN AREA RADAR IMAGERY. WHAT THE INBOUND AIRMASS WILL HAVE
IS GOOD MOISTURE QUALITY...SATURATION UPWARDS OF 30 KFT AND PWATS
THAT SPIKE OVER 1.0 INCH BY 12Z. GIVEN THE LESS THAN SPECTACULAR
FORCING...EXPECT A SOLID NUMEROUS/SCT COVERAGE OF LIGHT SHOWERS THIS
MORNING WITHIN THE ARC.

PRECIPITATION MAY REACH DTW BY 12Z.

12-19Z...NAM AND RAP SOLUTIONS DIVERGE AT THIS POINT ON TWO MAIN
POINTS...1. TIMING OF LEAD 700-500 DEFORMATION SURGE AND 2.
PRECIPITATION POTENTIAL WITHIN THIS ARC DURING THIS TIMEFRAME. RAP
IS FASTER/BULLISH ON PRECIPITATION WHILE THE NAM LAGS CONSIDERABLY.
GFS IS A COMPROMISE WITH FASTER TIMING...BUT MUCH LESS ON THE QPF.
TYPICALLY WOULD FAVOR THE BULLISH QPF AMOUNTS GIVEN OUTSTANDING
COLUMN SATURATION...BUT LACK OF DYNAMICS LEAVES ONE UNEASY. THE
DECIDING FACTOR HERE WILL BE OVERALL LACK OF LAPSE RATES AND
INSTABILITY AND FOR THAT REASON WILL SHAPE THE FORECAST WITH LOWER
QPF AMOUNTS IN LIGHTER SHOWER ACTIVITY...AN AVERAGED .05 THROUGH THE
M 59 CORRIDOR.

LIGHT SHOWER ACTIVITY MAY REACH PTK BY...1330Z.
                                FNT BY...1430Z.
     STALLING OUT JUST SOUTH OF MBS BY...16Z.

19-00Z...BAROCLINICITY IS LOW BUT NON-EXISTENT WITH THIS SYSTEM. IN
FACT...NAM IS SUGGESTING THAT A FRESH 850MB THETA E PLUME WILL
ADVECT STRAIGHT NORTHWARD...PUSHING INTO MUCH OF SOUTHEASTERN
MICHIGAN AFTER 18Z. GFS/NAM BOTH IN AGREEMENT THE CENTER OF 500MB
VORTICITY WILL LIFT ALONG THE WESTERN EDGE OF THIS THETA E GRADIENT
INTO FAR SOUTHEASTERN LOWER MICHIGAN BETWEEN 21-00Z. INTEGRITY OF
WARM FRONTAL FORCING AND THERMAL GRADIENTS ARE NOT IDEAL BUT MASS
ADJUSTMENTS ALONG IMMEDIATE NORTHWEST FLANK OF VORT MAX SHOULD CARVE
OUT A RESPONSE. NAM IS ON POINT WITH 850-500MB DEFORMATION
ORGANIZATION WHICH REPRESENTS THE SECOND SPIRAL DISCUSSED EARLIER.
THE BEST FORCING IS EXPECTED TO OCCUR ACROSS THE FAR EASTERN CWA
FROM MONROE UP THROUGH ST CLAIR COUNTIES. THIS FORCING MAY RESULT IN
A SOLID .2 INCHES OF QPF. ACCOUNTED FOR THIS WITH CATEGORICAL POPS
IN THOSE AREAS. ELEVATED THUNDER CHANCES APPEAR MINIMAL AND
RELEGATED TO EXTREME SOUTHEASTERN CWA BETWEEN 19-00Z...NEGATIVE
SHOWALTER INDICES HERE IN SEMICH ARE ALL POSITIVE...LOWERED THE
CHANCES ACROSS THE BOARD.

00-12Z...LIGHT SHOWERS AND/OR DRIZZLE MAY PERSIST ACROSS EXTREME
EASTERN AREAS/ST CLAIR COUNTY THROUGH 3-6Z TONIGHT WITH DEFORMATION
AXIS EVENTUALLY PEELING EASTWARD. FLOW TRAJECTORY MAY KEEP SHOWERS
JUST EAST OF THE CWA OVER PORTIONS OF CANADA THROUGH THE REMAINDER
OF THE NIGHT. EXPECT A GRUNGY AIRMASS TONIGHT WITH CLOUDS AND
POSSIBLY SOME FOG. NIL TEMPERATURE ADVECTION TONIGHT...SUPPORTS A
HIGH CONFIDENCE MIN T FORECAST RIGHT AROUND 50 DEGREES.

LONG TERM... MONDAY THROUGH SATURDAY

TODAY`S WAVE WILL DEPART TO THE EAST BY MONDAY MORNING AND LEAVE SE
MICHIGAN BETWEEN IT AND A COLD FRONT MOVING SLOWLY THROUGH THE
WESTERN GREAT LAKES. THE PARENT SURFACE LOW IS SHOWN IN THE MODEL
SOLUTIONS TO BE OVER THE FAR NORTHERN REACHES OF HUDSON BAY LEAVING
THE FRONT TO STALL AND WEAKEN OVER NORTHERN LOWER MICHIGAN. WE WILL
ALSO BE COUNTING ON BROAD SURFACE LOW PRESSURE DEVELOPMENT OVER THE
PLAINS TO HELP WASH OUT THE FRONT WITH INCREASING LARGE SCALE
GRADIENT FLOW OVER THE GREAT LAKES. THIS LOOKS LIKE A GOOD BET DUE
TO STRONG UPPER LEVEL HEIGHT FALLS OVER THE ROCKIES INITIATED BY A
POWERFUL JET MOVING INLAND FROM THE PACIFIC NORTHWEST. SATELLITE
IMAGERY THIS MORNING SHOWS THIS JET STRUCTURE NICELY WHICH THE
MODELS THEN RAMP UP TO ABOUT 150 KNOTS BY 12Z MONDAY AS IT DIGS INTO
THE ROCKIES. THESE DEVELOPMENTS IN THE LARGE SCALE PATTERN WILL PUT
A STOP TO THE EASTWARD ADVANCEMENT OF THE FRONT IN THE GREAT LAKES
AND EVENTUALLY LEAD TO ITS DECAY. EXPECT THAT ALL BUT POSSIBLY THE
TRI CITIES WILL REMAIN DRY AS A RESULT BEFORE A SLUG OF GULF
MOISTURE IS INDICATED MOVING IN MONDAY NIGHT. DEPICTIONS OF LOW TO
MID LEVEL THETA-E FIELDS SHOW THIS MOISTURE PATTERN TO BE A FRAGMENT
OF A BETTER ORGANIZED MOISTURE AXIS TAKING SHAPE OVER THE PLAINS.
GIVEN THE LIMITED PREDICTABILITY, IT IS BEST TO HOLD OFF ON ANY
EXPANSION OF POPS OUTSIDE OF THE TRI CITIES AND NORTHERN THUMB THAT
COULD CONTINUE TO BE AFFECTED BY MOISTURE REMNANTS FROM THE COLD
FRONT.

MODEL SOLUTIONS CONTINUE TO LOOK REASONABLE THROUGH TUESDAY WITH
SOUTHWEST FLOW INCREASING WHICH, ALONG WITH THE BUILDING UPPER RIDGE
OVER THE OHIO VALLEY, WILL CARRY TEMPERATURES WELL INTO THE 70S
DURING THE AFTERNOON. THERE ARE MIXED SIGNALS IN THE MOISTURE FIELDS
AMONGST THE NAM, GFS, AND ECMWF BUT ONLY WITH REGARD TO CLOUD COVER
RATHER THAN RAIN CHANCES. EVEN IF THERE IS SOME MID CLOUD LEFT TO
SCOUR OUT DURING THE DAY, EXPECT ENOUGH SURFACE HEATING TO REACH
GUIDANCE HIGHS IN THE UPPER 70S WITH 80 EVEN BEING A REASONABLE
UPPER END OF THE RANGE OVER THE INTERIOR OF LOWER MICHIGAN
SUFFICIENTLY INLAND FROM THE SHORELINES. MODEL SOUNDINGS INDICATE A
TYPICALLY MIXED BOUNDARY LAYER UP TO ABOUT 850 MB WHERE TEMPERATURE
IN THE 12 TO 14C RANGE WILL BE FAVORABLE FOR THE WARMING TREND.

IT WAS TEMPTING TO GO MORE BULLISH ON MAX TEMPS WEDNESDAY AS WELL,
BUT EVIDENCE OF BACKING SURFACE WIND SUGGESTS CAUTION. MODEL
DEPICTIONS OF THE UPPER TROUGH DIGGING TOWARD THE 4 CORNERS REGION
LOOK SOLID DURING THAT TIME PERIOD. THIS WILL SET UP AN EXTREMELY
SHARP BAROCLINIC ZONE FROM THE SOUTHERN HIGH PLAINS INTO UPPER
MICHIGAN. WHILE THE FRONT WILL REMAIN TO OUR WEST, A GREATER
EASTERLY SURFACE WIND COMPONENT WILL BRING LAKE AGGREGATE COOLING
FARTHER INLAND COMPARED TO TUESDAY. THIS WILL KEEP MAX TEMPS IN THE
70S FOR ALL BUT THE VERY INTERIOR SECTIONS OF LOWER MICHIGAN AND
EVEN IN THE 60S NEAR THE SHORELINES.

FOR THE END OF THE WEEK, THE GFS HAS MADE A CONSIDERABLE WESTWARD
ADJUSTMENT ON ITS SOLUTION FOR THE POSITION OF THE CLOSED LOW
THURSDAY INTO FRIDAY JOINING THE ECMWF AND CANADIAN IN A GENERAL
CLUSTER OF SOLUTIONS OVER THE CENTRAL PLAINS. THIS ADDS SOME
CONFIDENCE TO THE IDEA THAT SE MICHIGAN WEATHER WILL BE INFLUENCED
MORE BY THE UPPER LEVEL RIDGE PORTION OF THE DEVELOPING OMEGA
BLOCK OVER THE EASTERN HALF OF THE COUNTRY.

MARINE...

GENTLE TO MODERATE SOUTHEAST FLOW AND SIGNIFICANT WAVE HEIGHTS
AVERAGING 2 FEET OR LESS WILL PERSIST THROUGH MONDAY NIGHT BEFORE
SOUTHERLY FLOW RAMPS UP IN ADVANCE OF AN APPROACHING COLD FRONT. AN
ISOLATED THUNDERSTORM OR TWO WILL BE POSSIBLE OVER LAKE SAINT CLAIR
AND THE MICHIGAN WATERS OF LAKE ERIE AS SHOWERS SPREAD ACROSS THE
WATERS ON SUNDAY WITH MORE WIDESPREAD THUNDER POSSIBLE BY MIDWEEK.

&&

.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MI WATERS OF LAKE ERIE...NONE.

&&

$$

AVIATION.....KURIMSKI
UPDATE.......KURIMSKI
SHORT TERM...CB
LONG TERM....BT
MARINE.......CB


YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).







AREA FORECAST DISCUSSION

NWS MARQUETTE MI

 107 PM EDT SUN APR 28 2013

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 503 AM EDT SUN APR 28 2013

WV IMAGERY AND RUC ANALYSIS INDICATED ZONAL FLOW FROM THE PACIFIC NW
TO THE NRN GREAT LAKES. A SHORTWAVE TROUGH AND ASSOCIATED SFC LOW
WAS MOVING THROUGH ERN SASK INTO MANITOBA WITH A TROUGH EXTENDING TO
THE CNTRL DAKOTAS. AHEAD OF THE TROUGH...SSW FLOW WAS INCREASING
OVER THE UPPER MS VALLEY AND NRN GREAT LAKES. WITH THE DRY AIRMASS
BELOW 700 MB...PER 00Z INL SOUNDING...WAA AHEAD OF THE TROUGH WAS
BRINGING MAINLY MID CLOUDS AND SOME VIRGA OR SPRINKLES INTO NRN MN.
ALTHOUGH DEWPOINTS HAD CLIMBED INTO THE MID 40S SRN AND CNTRL
MN...CIRCULATION AROUND THE LOW PRESSURE SYSTEM OVER SRN IL HAD
PREVENTED MORE ABUNDANT GULF MOISTURE FROM MOVING INTO THE REGION.

EXPECT THAT SUNSHINE AND MIXING TO 850-800 MB (850 MB TEMPS FROM 7C
TO 9C) WILL REULS IN MAX READINGS IN THE MID AND UPPER 60S EAST AND
LOWER 70S WEST. SRLY FLOW OFF OF LAKE MICHIGAN WILL KEEP TEMPS
CLOSER TO 50.

AS THE SASKATCHEWAN LOW MOVES TO HUDSON BAY...IT WILL DRAG A COLD
FRONT INTO THE NRN GREAT LAKES TONIGHT. LOW LEVEL CONV NEAR THE
FRONT COMBINED WITH A WEAK SHORTWAVE MOVING OUT OF THE NRN PLAINS
WILL BE ENOUGH TO SUPPORT A BAND OF SHOWERS INTO UPPER MICHIGAN. THE
MODELS WERE IN GOOD AGREEMENT WITH THE FRONT AND PCPN BAND TRENDING
SLIGHTLY SLOWER. THE PCPN IS EXPECTED TO MOVE INTO THE WEST THIS
EVENING AND OVER THE CNTRL AND EAST OVERNIGHT. WITH ONLY WEAK
MID/UPPER LEVEL FORCING AND LIMITED MOISTURE INFLOW...OVERALL PCPN
AMOUNTS WILL BE LIGHT GENERALLY AOB 0.25 INCH...PER SREF PROB AND
CONSENSUS QPF. MDLS SUGGEST THAT ANY INSTABILITY TO SUPPORT TSRA WILL
REMAIN MAINLY TO THE S OF THE CWA.

.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 503 AM EDT SUN APR 28 2013

BEST CONFIDENCE INTO WEDNESDAY...WITH MUCH REDUCED FORECAST
CONFIDENCE AFTER THAT. PUT PRIMARY EFFORTS/TIME INTO SHORTER TERM
GRIDS GIVEN FLOODING PROBLEMS THAT WILL BE MORE CONFINED TO SHORTER
TERM.

FOR MON...EXPECT A WEAK SFC TROUGH/COLD FRONT TO PUSH
THROUGH...KEEPING SFC TEMPS A LITTLE COOLER THAN YESTERDAY OR TODAY.
UP TO AROUND A QUARTER INCH OF QPF IS EXPECTED MON...BUT AT THE SAME
TIME MELTING OF THE SNOW PACK IS REDUCED BY EXTRA CLOUD COVER AND
COOLER TEMPS /ESPECIALLY NEAR LAKE SUPERIOR/...SO THESE TWO FACTORS
MAY CANCEL EACH OTHER OUT...STILL RESULTING IN A DECENT MELT
DAY...BUT THIS IS DIFFICULT TO DETERMINE.

TEMPORARY COOL DOWN MON COMES TO YET ANOTHER END WITH 60S AND 70
HIGH TEMPS OVER MUCH OF THE AREA TUE AS 850MB TEMPS INCREASE TO
AROUND 14C BY 18Z TUE. THESE WARMER TEMPS COME AHEAD OF ANOTHER
SYSTEM THAT WILL MOVE N OF LAKE SUPERIOR...WHICH BRINGS A COLD FRONT
ACROSS THE CWA LATE TUE INTO TUE NIGHT. MODELS ARE EVEN SHOWING
SOME CAPE ALONG AND AHEAD OF THE COLD FRONT...WHICH MAY RESULT IN
THUNDERSTORM ACTIVITY. THE HEAVIEST RAINFALL IS MAINLY FOCUSED OVER
THE ERN HALF OFF UPPER MI...AND WILL BE SOMETHING TO WATCH WITH
RESPECT TO CONTINUED FLOOD THREAT.

OTHER THAN THOSE SYSTEM...MODELS IN THE FARTHER EXTENDED SHOW LARGE
DISAGREEMENT IN THERMAL FIELDS...SO A WIDE VARIETY OF TEMPS ARE
POSSIBLE. ALTHOUGH MODELS DO SHOW GOOD GENERAL AGREEMENT...THE EXACT
PLACEMENT OF THE UPPER LOW THEY SHOW OVER THE CENTRAL CONUS BY FRI
IS ESSENTIAL FOR TEMPS/PRECIP. WILL JUST USE A CONSENSUS OF MODELS
FOR THIS PERIOD GIVEN THE UNCERTAINTY.
&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 107 PM EDT SUN APR 28 2013

EXPECT VFR CONDITIONS TO PREVAIL THROUGH THIS EVENING WITH THE
RELATIVELY DRY AIRMASS DOMINATING IN SW FLOW AROUND HIGH PRESSURE
OVER NEW ENGLAND. SOME -SHRA WL ARRIVE AT IWD/CMX AFT 02Z AHEAD OF
AN INCOMING COLD FRONT...BUT LIMITED MSTR RETURN WL LIMIT PCPN
INTENSITY AND THE POTENTIAL FOR CONDITIONS LOWER THAN VFR. AFTER
06Z...EXPECT ENOUGH LOW LEVEL MOISTENING FOR MVFR CONDITIONS TO
DEVELOP AT ALL TAF SITES. SOME IMPROVEMENT IS EXPECTED WITH DRIER
AIR COMING IN MON MORNING AT ALL SITES. CONDITIONS WILL GO BACK TO
VFR AT IWD AND SAW WITH HIGHER MVFR CIGS AT CMX.
&&

.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 503 AM EDT SUN APR 28 2013

WINDS SHOULD STAY BELOW 25KTS THROUGH THE PERIOD WITH NO GALES IN
SIGHT. NO STRONG SYSTEMS WILL BE COMING CLOSE TO THE AREA...SO NO
STRONG PRESSURE GRADIENTS ARE EXPECTED.
&&

.HYDROLOGY...
ISSUED AT 503 AM EDT SUN APR 28 2013

SAW GOOD MELTING YESTERDAY AFTERNOON WITH HIGH TEMPS IN THE 60S AND
70S AFTER THE SNOW PACK WARMED UP FROM SUB-FREEZING TEMPS THE NIGHT
BEFORE. SINCE TEMPS ARE WELL ABOVE FREEZING TONIGHT...AND HIGH TEMPS
TODAY WILL BE SIMILAR TO YESTERDAY BUT WITH SLIGHTLY HIGHER DEW
POINTS...WE SHOULD SEE EVEN BETTER MELTING FOR A LONGER PERIOD OF
TIME THAN YESTERDAY. PLACES WITH SNOWPACK REMAINING WILL SEE RAPID
AND EXTENSIVE MELTING TODAY...CAUSING RUNOFF INTO TONIGHT INTO AREA
STREAMS. RIVERS OF PARTICULAR CONCERN AFTER THE MELTING TODAY WILL
BE THE TRAP ROCK RIVER...THE STURGEON RIVER OF BARAGA/HOUGHTON
COUNTIES...AND THE PESHEKEE RIVER. RUNOFF MAY NOT PEAK UNTIL
TONIGHT/MONDAY...AND EVEN GET FORTIFIED BY ADDITIONAL MELTING AND
EVEN SOME RAIN ON MONDAY. RAINFALL AMOUNTS WILL GENERALLY BE AROUND
A QUARTER OF AN INCH...OR POSSIBLY MORE IN A FEW AREAS AND WILL
START LATE THIS EVENING INTO MONDAY. ANY RAIN WILL ONLY ADD TO
HYDROLOGIC CONCERNS...AND WILL HAVE TO PAY CLOSE ATTENTION TO PRECIP
AMOUNTS MONDAY. FURTHER CHANCES OF PRECIPITATION ARE EXPECTED AS
COLD FRONT WORKS THROUGH ON TUESDAY...WHEN THERE MAY BE
THUNDERSTORMS TOO. OTHERWISE...ADDITIONAL CHANCES OF PRECIPITATION
ARE POSSIBLE THE REST OF THE WEEK AS FRONT STAYS CLOSE BY TO THE
AREA.

MELTING SCENARIOS REMAIN THE BIGGEST CONFIDENCE REDUCERS AT THIS
POINT...AND IF THE RIVER FORECAST CENTER HAS TO INCREASE THE MELT
FACTOR CORRECTION GOING INTO THE RIVER MODELS THE FORECASTS WILL
LIKELY END UP QUITE A BIT HIGHER. ONCE PLACE WHERE THE MELT
CORRECTION FACTOR WAS INCREASED FOR FOR THE MEN RIVER FORECAST GROUP
/RIVERS THAT DRAIN INTO THE MENOMINEE RIVER/...WHICH RESULTED IN
MUCH INCREASED FORECASTS UP TO NEAR RECORD STAGE AT PESHEKEE AND
MODERATE FLOOD STAGE DOWNSTREAM ON THE MICHIGAMME RIVER NEAR
REPUBLIC/WITCH LAKE. WFO SURVEY OF THE PESHEKEE RIVER REVEALED THICK
ICE COVERING MOST OF THE RIVER AND THICK ICE COVER MOST OF LAKE
MICHIGAMME WHICH THE PESHEKEE DRAINS INTO. ICE JAMS COULD CAUSE
SIGNIFICANT PROBLEMS AS THE RIVER RISES LATE TODAY INTO MONDAY. OF
COURSE...MAIN STEM RIVERS ARE NOT THE ONLY HAZARD...AS WE ARE ALSO
LOOKING AT THREAT OF AREAL FLOOD PROBLEMS WITH SMALLER
CREEKS/STREAMS AND STANDING WATER ON ROADS. FOR FURTHER
DETAILS...SEE THE HYDROLOGIC OUTLOOK /ESF/ AND THE LATEST RIVER
WATCHES /FFAMQT/.
&&

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

$$

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







AREA FORECAST DISCUSSION

NWS DETROIT/PONTIAC MI

 1056 AM EDT SUN APR 28 2013

.UPDATE...

RAIN SHOWERS CONTINUE TO EDGE NORTHWARD INTO SOUTHEASTERN MICHIGAN
DURING THE LATE MORNING HOURS. HOWEVER THEY ARE ENCOUNTERING QUITE
A BIT OF LOW LEVEL DRY AIR AS EVIDENCED BY THE 12Z DTX RAOB
SOUNDING. THE LOCAL HI-RES MODELS ARE CAPTURING THIS QUITE WELL
AND KEEP MUCH OF THE ACTIVITY ALONG AND SOUTH OF M-59 THROUGH THE
EARLY AFTERNOON...THEN TRANSITIONING OFF TO THE EAST AS THE LOW
TRACKS EAST THROUGH OHIO. GIVEN THE ABUNDANT DRY AIR IN PLACE
ACROSS THE NORTH AND THE PERFORMANCE OF THE LOCAL 3KM HRRR MODEL
WILL TIGHTEN UP THE POPS ACROSS THE CWA...LOWERING AMOUNTS ACROSS
THE NORTH AND RAISING THEM ACROSS THE SOUTH.


&&

.AVIATION...ISSUED 717 AM EDT SUN APR 28 2013

//DISCUSSION...

INITIAL MOISTURE SURGE AND ELEVATED FORCING WILL SLIDE OVERHEAD OF
THE SOUTHERN TAF SITES DURING THE MORNING. A DRAMATIC LOWERING OF
CIGS TO MVFR IS EXPECTED WITH THIS FIRST PUSH OF MOISTURE. LIFR TO
VLIFR CEILINGS ARE THEN EXPECTED AFTER 19Z AS SECOND AREA OF
DEFORMATION FORCING DEVELOPS OVER EXTREME SECTIONS OF SOUTHEASTERN
MICHIGAN. MOISTURE QUALITY WILL BE HIGH WHICH BRINGS INCREASED
CONFIDENCE IN THE DEGRADATION OF AVIATION CONDITIONS FOR A LONG
DURATION TONIGHT.

FOR DTW...LINEAR EXTRAPOLATION OF LEAD MOISTURE SURGE IS SET FOR
NO LATER THAN 13Z THIS MORNING. A SECOND AREA OF FORCING WILL
ORGANIZE THIS AFTERNOON AND ALIGN SOUTHWEST TO NORTHEAST OVER THE
AREA. THE ADDITIONAL FORCING OVER A MOISTURE LADEN AIR MASS WILL
BRING A MEDIUM TO HIGH POTENTIAL FOR VLIFR CONDITIONS THROUGHOUT
TONIGHT.

//DTW THRESHOLD THREATS...

* HIGH CONFIDENCE IN CEILINGS BELOW 5000 FEET BY 11Z-13Z.

* MEDIUM TO HIGH CONFIDENCE IN CEILINGS DOWN TO 200 FEET AFTER 00Z
SUNDAY.

&&

.PREV DISCUSSION...ISSUED 356 AM EDT SUN APR 28 2013

SHORT TERM...TODAY AND TONIGHT

08-12Z...AN AMPLITUDE INCREASE OF THE EASTERN NORTH AMERICA LONGWAVE
RIDGE WILL BE THE FORCING MECHANISM WHICH WILL DRAW THE SOUTHERN IL
PV ANOMALY NORTHWARD INTO MICHIGAN TODAY. TWO SPIRALS OF 700-500MB
DEFORMATION WILL EMANATE NORTHWARD AWAY FROM THE PARENT VORTICITY
MAXIMUM THE FIRST OF WHICH WILL LIFT ACROSS THE MICHIGAN/OHIO
STATELINE AFTER 9Z. THIS IS ADVERTISED BY LINEAR EXTRAPOLATION FROM
RADAR MOSAIC AND TIMING OF NAM/RAP. DEFORMATION FORCING WILL BE
COASTING INTO THE STATE...WEAKENING DRAMATICALLY ACCORDING TO NWP
PROJECTIONS. FEEL GOOD ABOUT THIS GIVEN INCREASING DISTANCE FROM
VORTICITY MAXIMUM...WARMING CLOUD TOPS IN LATEST IR...AND SPOTTY
COVERAGE IN AREA RADAR IMAGERY. WHAT THE INBOUND AIRMASS WILL HAVE
IS GOOD MOISTURE QUALITY...SATURATION UPWARDS OF 30 KFT AND PWATS
THAT SPIKE OVER 1.0 INCH BY 12Z. GIVEN THE LESS THAN SPECTACULAR
FORCING...EXPECT A SOLID NUMEROUS/SCT COVERAGE OF LIGHT SHOWERS THIS
MORNING WITHIN THE ARC.

PRECIPITATION MAY REACH DTW BY 12Z.

12-19Z...NAM AND RAP SOLUTIONS DIVERGE AT THIS POINT ON TWO MAIN
POINTS...1. TIMING OF LEAD 700-500 DEFORMATION SURGE AND 2.
PRECIPITATION POTENTIAL WITHIN THIS ARC DURING THIS TIMEFRAME. RAP
IS FASTER/BULLISH ON PRECIPITATION WHILE THE NAM LAGS CONSIDERABLY.
GFS IS A COMPROMISE WITH FASTER TIMING...BUT MUCH LESS ON THE QPF.
TYPICALLY WOULD FAVOR THE BULLISH QPF AMOUNTS GIVEN OUTSTANDING
COLUMN SATURATION...BUT LACK OF DYNAMICS LEAVES ONE UNEASY. THE
DECIDING FACTOR HERE WILL BE OVERALL LACK OF LAPSE RATES AND
INSTABILITY AND FOR THAT REASON WILL SHAPE THE FORECAST WITH LOWER
QPF AMOUNTS IN LIGHTER SHOWER ACTIVITY...AN AVERAGED .05 THROUGH THE
M 59 CORRIDOR.

LIGHT SHOWER ACTIVITY MAY REACH PTK BY...1330Z.
                                FNT BY...1430Z.
     STALLING OUT JUST SOUTH OF MBS BY...16Z.

19-00Z...BAROCLINICITY IS LOW BUT NON-EXISTENT WITH THIS SYSTEM. IN
FACT...NAM IS SUGGESTING THAT A FRESH 850MB THETA E PLUME WILL
ADVECT STRAIGHT NORTHWARD...PUSHING INTO MUCH OF SOUTHEASTERN
MICHIGAN AFTER 18Z. GFS/NAM BOTH IN AGREEMENT THE CENTER OF 500MB
VORTICITY WILL LIFT ALONG THE WESTERN EDGE OF THIS THETA E GRADIENT
INTO FAR SOUTHEASTERN LOWER MICHIGAN BETWEEN 21-00Z. INTEGRITY OF
WARM FRONTAL FORCING AND THERMAL GRADIENTS ARE NOT IDEAL BUT MASS
ADJUSTMENTS ALONG IMMEDIATE NORTHWEST FLANK OF VORT MAX SHOULD CARVE
OUT A RESPONSE. NAM IS ON POINT WITH 850-500MB DEFORMATION
ORGANIZATION WHICH REPRESENTS THE SECOND SPIRAL DISCUSSED EARLIER.
THE BEST FORCING IS EXPECTED TO OCCUR ACROSS THE FAR EASTERN CWA
FROM MONROE UP THROUGH ST CLAIR COUNTIES. THIS FORCING MAY RESULT IN
A SOLID .2 INCHES OF QPF. ACCOUNTED FOR THIS WITH CATEGORICAL POPS
IN THOSE AREAS. ELEVATED THUNDER CHANCES APPEAR MINIMAL AND
RELEGATED TO EXTREME SOUTHEASTERN CWA BETWEEN 19-00Z...NEGATIVE
SHOWALTER INDICES HERE IN SEMICH ARE ALL POSITIVE...LOWERED THE
CHANCES ACROSS THE BOARD.

00-12Z...LIGHT SHOWERS AND/OR DRIZZLE MAY PERSIST ACROSS EXTREME
EASTERN AREAS/ST CLAIR COUNTY THROUGH 3-6Z TONIGHT WITH DEFORMATION
AXIS EVENTUALLY PEELING EASTWARD. FLOW TRAJECTORY MAY KEEP SHOWERS
JUST EAST OF THE CWA OVER PORTIONS OF CANADA THROUGH THE REMAINDER
OF THE NIGHT. EXPECT A GRUNGY AIRMASS TONIGHT WITH CLOUDS AND
POSSIBLY SOME FOG. NIL TEMPERATURE ADVECTION TONIGHT...SUPPORTS A
HIGH CONFIDENCE MIN T FORECAST RIGHT AROUND 50 DEGREES.

LONG TERM... MONDAY THROUGH SATURDAY

TODAY`S WAVE WILL DEPART TO THE EAST BY MONDAY MORNING AND LEAVE SE
MICHIGAN BETWEEN IT AND A COLD FRONT MOVING SLOWLY THROUGH THE
WESTERN GREAT LAKES. THE PARENT SURFACE LOW IS SHOWN IN THE MODEL
SOLUTIONS TO BE OVER THE FAR NORTHERN REACHES OF HUDSON BAY LEAVING
THE FRONT TO STALL AND WEAKEN OVER NORTHERN LOWER MICHIGAN. WE WILL
ALSO BE COUNTING ON BROAD SURFACE LOW PRESSURE DEVELOPMENT OVER THE
PLAINS TO HELP WASH OUT THE FRONT WITH INCREASING LARGE SCALE
GRADIENT FLOW OVER THE GREAT LAKES. THIS LOOKS LIKE A GOOD BET DUE
TO STRONG UPPER LEVEL HEIGHT FALLS OVER THE ROCKIES INITIATED BY A
POWERFUL JET MOVING INLAND FROM THE PACIFIC NORTHWEST. SATELLITE
IMAGERY THIS MORNING SHOWS THIS JET STRUCTURE NICELY WHICH THE
MODELS THEN RAMP UP TO ABOUT 150 KNOTS BY 12Z MONDAY AS IT DIGS INTO
THE ROCKIES. THESE DEVELOPMENTS IN THE LARGE SCALE PATTERN WILL PUT
A STOP TO THE EASTWARD ADVANCEMENT OF THE FRONT IN THE GREAT LAKES
AND EVENTUALLY LEAD TO ITS DECAY. EXPECT THAT ALL BUT POSSIBLY THE
TRI CITIES WILL REMAIN DRY AS A RESULT BEFORE A SLUG OF GULF
MOISTURE IS INDICATED MOVING IN MONDAY NIGHT. DEPICTIONS OF LOW TO
MID LEVEL THETA-E FIELDS SHOW THIS MOISTURE PATTERN TO BE A FRAGMENT
OF A BETTER ORGANIZED MOISTURE AXIS TAKING SHAPE OVER THE PLAINS.
GIVEN THE LIMITED PREDICTABILITY, IT IS BEST TO HOLD OFF ON ANY
EXPANSION OF POPS OUTSIDE OF THE TRI CITIES AND NORTHERN THUMB THAT
COULD CONTINUE TO BE AFFECTED BY MOISTURE REMNANTS FROM THE COLD
FRONT.

MODEL SOLUTIONS CONTINUE TO LOOK REASONABLE THROUGH TUESDAY WITH
SOUTHWEST FLOW INCREASING WHICH, ALONG WITH THE BUILDING UPPER RIDGE
OVER THE OHIO VALLEY, WILL CARRY TEMPERATURES WELL INTO THE 70S
DURING THE AFTERNOON. THERE ARE MIXED SIGNALS IN THE MOISTURE FIELDS
AMONGST THE NAM, GFS, AND ECMWF BUT ONLY WITH REGARD TO CLOUD COVER
RATHER THAN RAIN CHANCES. EVEN IF THERE IS SOME MID CLOUD LEFT TO
SCOUR OUT DURING THE DAY, EXPECT ENOUGH SURFACE HEATING TO REACH
GUIDANCE HIGHS IN THE UPPER 70S WITH 80 EVEN BEING A REASONABLE
UPPER END OF THE RANGE OVER THE INTERIOR OF LOWER MICHIGAN
SUFFICIENTLY INLAND FROM THE SHORELINES. MODEL SOUNDINGS INDICATE A
TYPICALLY MIXED BOUNDARY LAYER UP TO ABOUT 850 MB WHERE TEMPERATURE
IN THE 12 TO 14C RANGE WILL BE FAVORABLE FOR THE WARMING TREND.

IT WAS TEMPTING TO GO MORE BULLISH ON MAX TEMPS WEDNESDAY AS WELL,
BUT EVIDENCE OF BACKING SURFACE WIND SUGGESTS CAUTION. MODEL
DEPICTIONS OF THE UPPER TROUGH DIGGING TOWARD THE 4 CORNERS REGION
LOOK SOLID DURING THAT TIME PERIOD. THIS WILL SET UP AN EXTREMELY
SHARP BAROCLINIC ZONE FROM THE SOUTHERN HIGH PLAINS INTO UPPER
MICHIGAN. WHILE THE FRONT WILL REMAIN TO OUR WEST, A GREATER
EASTERLY SURFACE WIND COMPONENT WILL BRING LAKE AGGREGATE COOLING
FARTHER INLAND COMPARED TO TUESDAY. THIS WILL KEEP MAX TEMPS IN THE
70S FOR ALL BUT THE VERY INTERIOR SECTIONS OF LOWER MICHIGAN AND
EVEN IN THE 60S NEAR THE SHORELINES.

FOR THE END OF THE WEEK, THE GFS HAS MADE A CONSIDERABLE WESTWARD
ADJUSTMENT ON ITS SOLUTION FOR THE POSITION OF THE CLOSED LOW
THURSDAY INTO FRIDAY JOINING THE ECMWF AND CANADIAN IN A GENERAL
CLUSTER OF SOLUTIONS OVER THE CENTRAL PLAINS. THIS ADDS SOME
CONFIDENCE TO THE IDEA THAT SE MICHIGAN WEATHER WILL BE INFLUENCED
MORE BY THE UPPER LEVEL RIDGE PORTION OF THE DEVELOPING OMEGA
BLOCK OVER THE EASTERN HALF OF THE COUNTRY.

MARINE...

GENTLE TO MODERATE SOUTHEAST FLOW AND SIGNIFICANT WAVE HEIGHTS
AVERAGING 2 FEET OR LESS WILL PERSIST THROUGH MONDAY NIGHT BEFORE
SOUTHERLY FLOW RAMPS UP IN ADVANCE OF AN APPROACHING COLD FRONT. AN
ISOLATED THUNDERSTORM OR TWO WILL BE POSSIBLE OVER LAKE SAINT CLAIR
AND THE MICHIGAN WATERS OF LAKE ERIE AS SHOWERS SPREAD ACROSS THE
WATERS ON SUNDAY WITH MORE WIDESPREAD THUNDER POSSIBLE BY MIDWEEK.

&&

.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MI WATERS OF LAKE ERIE...NONE.

&&

$$

UPDATE.......KURIMSKI
AVIATION.....CB
SHORT TERM...CB
LONG TERM....BT
MARINE.......CB


YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).







AREA FORECAST DISCUSSION

NWS MARQUETTE MI

 741 AM EDT SUN APR 28 2013

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 503 AM EDT SUN APR 28 2013

WV IMAGERY AND RUC ANALYSIS INDICATED ZONAL FLOW FROM THE PACIFIC NW
TO THE NRN GREAT LAKES. A SHORTWAVE TROUGH AND ASSOCIATED SFC LOW
WAS MOVING THROUGH ERN SASK INTO MANITOBA WITH A TROUGH EXTENDING TO
THE CNTRL DAKOTAS. AHEAD OF THE TROUGH...SSW FLOW WAS INCREASING
OVER THE UPPER MS VALLEY AND NRN GREAT LAKES. WITH THE DRY AIRMASS
BELOW 700 MB...PER 00Z INL SOUNDING...WAA AHEAD OF THE TROUGH WAS
BRINGING MAINLY MID CLOUDS AND SOME VIRGA OR SPRINKLES INTO NRN MN.
ALTHOUGH DEWPOINTS HAD CLIMBED INTO THE MID 40S SRN AND CNTRL
MN...CIRCULATION AROUND THE LOW PRESSURE SYSTEM OVER SRN IL HAD
PREVENTED MORE ABUNDANT GULF MOISTURE FROM MOVING INTO THE REGION.

EXPECT THAT SUNSHINE AND MIXING TO 850-800 MB (850 MB TEMPS FROM 7C
TO 9C) WILL REULS IN MAX READINGS IN THE MID AND UPPER 60S EAST AND
LOWER 70S WEST. SRLY FLOW OFF OF LAKE MICHIGAN WILL KEEP TEMPS
CLOSER TO 50.

AS THE SASKATCHEWAN LOW MOVES TO HUDSON BAY...IT WILL DRAG A COLD
FRONT INTO THE NRN GREAT LAKES TONIGHT. LOW LEVEL CONV NEAR THE
FRONT COMBINED WITH A WEAK SHORTWAVE MOVING OUT OF THE NRN PLAINS
WILL BE ENOUGH TO SUPPORT A BAND OF SHOWERS INTO UPPER MICHIGAN. THE
MODELS WERE IN GOOD AGREEMENT WITH THE FRONT AND PCPN BAND TRENDING
SLIGHTLY SLOWER. THE PCPN IS EXPECTED TO MOVE INTO THE WEST THIS
EVENING AND OVER THE CNTRL AND EAST OVERNIGHT. WITH ONLY WEAK
MID/UPPER LEVEL FORCING AND LIMITED MOISTURE INFLOW...OVERALL PCPN
AMOUNTS WILL BE LIGHT GENERALLY AOB 0.25 INCH...PER SREF PROB AND
CONSENSUS QPF. MDLS SUGGEST THAT ANY INSTABILITY TO SUPPORT TSRA WILL
REMAIN MAINLY TO THE S OF THE CWA.

.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 503 AM EDT SUN APR 28 2013

BEST CONFIDENCE INTO WEDNESDAY...WITH MUCH REDUCED FORECAST
CONFIDENCE AFTER THAT. PUT PRIMARY EFFORTS/TIME INTO SHORTER TERM
GRIDS GIVEN FLOODING PROBLEMS THAT WILL BE MORE CONFINED TO SHORTER
TERM.

FOR MON...EXPECT A WEAK SFC TROUGH/COLD FRONT TO PUSH
THROUGH...KEEPING SFC TEMPS A LITTLE COOLER THAN YESTERDAY OR TODAY.
UP TO AROUND A QUARTER INCH OF QPF IS EXPECTED MON...BUT AT THE SAME
TIME MELTING OF THE SNOW PACK IS REDUCED BY EXTRA CLOUD COVER AND
COOLER TEMPS /ESPECIALLY NEAR LAKE SUPERIOR/...SO THESE TWO FACTORS
MAY CANCEL EACH OTHER OUT...STILL RESULTING IN A DECENT MELT
DAY...BUT THIS IS DIFFICULT TO DETERMINE.

TEMPORARY COOL DOWN MON COMES TO YET ANOTHER END WITH 60S AND 70
HIGH TEMPS OVER MUCH OF THE AREA TUE AS 850MB TEMPS INCREASE TO
AROUND 14C BY 18Z TUE. THESE WARMER TEMPS COME AHEAD OF ANOTHER
SYSTEM THAT WILL MOVE N OF LAKE SUPERIOR...WHICH BRINGS A COLD FRONT
ACROSS THE CWA LATE TUE INTO TUE NIGHT. MODELS ARE EVEN SHOWING
SOME CAPE ALONG AND AHEAD OF THE COLD FRONT...WHICH MAY RESULT IN
THUNDERSTORM ACTIVITY. THE HEAVIEST RAINFALL IS MAINLY FOCUSED OVER
THE ERN HALF OFF UPPER MI...AND WILL BE SOMETHING TO WATCH WITH
RESPECT TO CONTINUED FLOOD THREAT.

OTHER THAN THOSE SYSTEM...MODELS IN THE FARTHER EXTENDED SHOW LARGE
DISAGREEMENT IN THERMAL FIELDS...SO A WIDE VARIETY OF TEMPS ARE
POSSIBLE. ALTHOUGH MODELS DO SHOW GOOD GENERAL AGREEMENT...THE EXACT
PLACEMENT OF THE UPPER LOW THEY SHOW OVER THE CENTRAL CONUS BY FRI
IS ESSENTIAL FOR TEMPS/PRECIP. WILL JUST USE A CONSENSUS OF MODELS
FOR THIS PERIOD GIVEN THE UNCERTAINTY.
&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 739 AM EDT SUN APR 28 2013

EXPECT VFR CONDITIONS TO PREVAIL TODAY INTO THIS EVENING WITH THE
RELATIVELY DRY AIRMASS DOMINATING IN SW FLOW AROUND HIGH PRESSURE
OVER NEW ENGLAND. THE ONSET OF DAYTIME HEATING BY MID/LATE MORNING
WILL MIX OUT ANY HIGHER WINDS LEADING TO LLWS AND ALLOW GUSTY SW
WINDS TO REACH THE SFC. SOME -SHRA WL ARRIVE AT IWD/CMX AFT 00Z
AHEAD OF AN INCOMING COLD FRONT...BUT LIMITED MOISTURE RETURN WILL
LIMIT PCPN INTENSITY AND THE POTENTIAL FOR CONDITIONS LOWER THAN
VFR. BY LATE EVENING AND OVERNIGHT...EXPECT ENOUGH LOW LEVEL
MOISTENING FOR MVFR CONDITIONS TO DEVELOP.
&&

.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 503 AM EDT SUN APR 28 2013

WINDS SHOULD STAY BELOW 25KTS THROUGH THE PERIOD WITH NO GALES IN
SIGHT. NO STRONG SYSTEMS WILL BE COMING CLOSE TO THE AREA...SO NO
STRONG PRESSURE GRADIENTS ARE EXPECTED.
&&

.HYDROLOGY...
ISSUED AT 503 AM EDT SUN APR 28 2013

SAW GOOD MELTING YESTERDAY AFTERNOON WITH HIGH TEMPS IN THE 60S AND
70S AFTER THE SNOW PACK WARMED UP FROM SUB-FREEZING TEMPS THE NIGHT
BEFORE. SINCE TEMPS ARE WELL ABOVE FREEZING TONIGHT...AND HIGH TEMPS
TODAY WILL BE SIMILAR TO YESTERDAY BUT WITH SLIGHTLY HIGHER DEW
POINTS...WE SHOULD SEE EVEN BETTER MELTING FOR A LONGER PERIOD OF
TIME THAN YESTERDAY. PLACES WITH SNOWPACK REMAINING WILL SEE RAPID
AND EXTENSIVE MELTING TODAY...CAUSING RUNOFF INTO TONIGHT INTO AREA
STREAMS. RIVERS OF PARTICULAR CONCERN AFTER THE MELTING TODAY WILL
BE THE TRAP ROCK RIVER...THE STURGEON RIVER OF BARAGA/HOUGHTON
COUNTIES...AND THE PESHEKEE RIVER. RUNOFF MAY NOT PEAK UNTIL
TONIGHT/MONDAY...AND EVEN GET FORTIFIED BY ADDITIONAL MELTING AND
EVEN SOME RAIN ON MONDAY. RAINFALL AMOUNTS WILL GENERALLY BE AROUND
A QUARTER OF AN INCH...OR POSSIBLY MORE IN A FEW AREAS AND WILL
START LATE THIS EVENING INTO MONDAY. ANY RAIN WILL ONLY ADD TO
HYDROLOGIC CONCERNS...AND WILL HAVE TO PAY CLOSE ATTENTION TO PRECIP
AMOUNTS MONDAY. FURTHER CHANCES OF PRECIPITATION ARE EXPECTED AS
COLD FRONT WORKS THROUGH ON TUESDAY...WHEN THERE MAY BE
THUNDERSTORMS TOO. OTHERWISE...ADDITIONAL CHANCES OF PRECIPITATION
ARE POSSIBLE THE REST OF THE WEEK AS FRONT STAYS CLOSE BY TO THE
AREA.

MELTING SCENARIOS REMAIN THE BIGGEST CONFIDENCE REDUCERS AT THIS
POINT...AND IF THE RIVER FORECAST CENTER HAS TO INCREASE THE MELT
FACTOR CORRECTION GOING INTO THE RIVER MODELS THE FORECASTS WILL
LIKELY END UP QUITE A BIT HIGHER. ONCE PLACE WHERE THE MELT
CORRECTION FACTOR WAS INCREASED FOR FOR THE MEN RIVER FORECAST GROUP
/RIVERS THAT DRAIN INTO THE MENOMINEE RIVER/...WHICH RESULTED IN
MUCH INCREASED FORECASTS UP TO NEAR RECORD STAGE AT PESHEKEE AND
MODERATE FLOOD STAGE DOWNSTREAM ON THE MICHIGAMME RIVER NEAR
REPUBLIC/WITCH LAKE. WFO SURVEY OF THE PESHEKEE RIVER REVEALED THICK
ICE COVERING MOST OF THE RIVER AND THICK ICE COVER MOST OF LAKE
MICHIGAMME WHICH THE PESHEKEE DRAINS INTO. ICE JAMS COULD CAUSE
SIGNIFICANT PROBLEMS AS THE RIVER RISES LATE TODAY INTO MONDAY. OF
COURSE...MAIN STEM RIVERS ARE NOT THE ONLY HAZARD...AS WE ARE ALSO
LOOKING AT THREAT OF AREAL FLOOD PROBLEMS WITH SMALLER
CREEKS/STREAMS AND STANDING WATER ON ROADS. FOR FURTHER
DETAILS...SEE THE HYDROLOGIC OUTLOOK /ESF/ AND THE LATEST RIVER
WATCHES /FFAMQT/.
&&

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

$$

SHORT TERM...JLB
LONG TERM...TITUS
AVIATION...JLB
MARINE...JLB
HYDROLOGY...TITUS







AREA FORECAST DISCUSSION

NWS DETROIT/PONTIAC MI

 717 AM EDT SUN APR 28 2013

.AVIATION...

//DISCUSSION...

INITIAL MOISTURE SURGE AND ELEVATED FORCING WILL SLIDE OVERHEAD OF
THE SOUTHERN TAF SITES DURING THE MORNING. A DRAMATIC LOWERING OF
CIGS TO MVFR IS EXPECTED WITH THIS FIRST PUSH OF MOISTURE. LIFR TO
VLIFR CEILINGS ARE THEN EXPECTED AFTER 19Z AS SECOND AREA OF
DEFORMATION FORCING DEVELOPS OVER EXTREME SECTIONS OF SOUTHEASTERN
MICHIGAN. MOISTURE QUALITY WILL BE HIGH WHICH BRINGS INCREASED
CONFIDENCE IN THE DEGRADATION OF AVIATION CONDITIONS FOR A LONG
DURATION TONIGHT.

FOR DTW...LINEAR EXTRAPOLATION OF LEAD MOISTURE SURGE IS SET FOR
NO LATER THAN 13Z THIS MORNING. A SECOND AREA OF FORCING WILL
ORGANIZE THIS AFTERNOON AND ALIGN SOUTHWEST TO NORTHEAST OVER THE
AREA. THE ADDITIONAL FORCING OVER A MOISTURE LADEN AIR MASS WILL
BRING A MEDIUM TO HIGH POTENTIAL FOR VLIFR CONDITIONS THROUGHOUT
TONIGHT.

//DTW THRESHOLD THREATS...

* HIGH CONFIDENCE IN CEILINGS BELOW 5000 FEET BY 11Z-13Z.

* MEDIUM TO HIGH CONFIDENCE IN CEILINGS DOWN TO 200 FEET AFTER 00Z
SUNDAY.

&&

.PREV DISCUSSION...ISSUED 356 AM EDT SUN APR 28 2013

SHORT TERM...TODAY AND TONIGHT

08-12Z...AN AMPLITUDE INCREASE OF THE EASTERN NORTH AMERICA LONGWAVE
RIDGE WILL BE THE FORCING MECHANISM WHICH WILL DRAW THE SOUTHERN IL
PV ANOMALY NORTHWARD INTO MICHIGAN TODAY. TWO SPIRALS OF 700-500MB
DEFORMATION WILL EMANATE NORTHWARD AWAY FROM THE PARENT VORTICITY
MAXIMUM THE FIRST OF WHICH WILL LIFT ACROSS THE MICHIGAN/OHIO
STATELINE AFTER 9Z. THIS IS ADVERTISED BY LINEAR EXTRAPOLATION FROM
RADAR MOSAIC AND TIMING OF NAM/RAP. DEFORMATION FORCING WILL BE
COASTING INTO THE STATE...WEAKENING DRAMATICALLY ACCORDING TO NWP
PROJECTIONS. FEEL GOOD ABOUT THIS GIVEN INCREASING DISTANCE FROM
VORTICITY MAXIMUM...WARMING CLOUD TOPS IN LATEST IR...AND SPOTTY
COVERAGE IN AREA RADAR IMAGERY. WHAT THE INBOUND AIRMASS WILL HAVE
IS GOOD MOISTURE QUALITY...SATURATION UPWARDS OF 30 KFT AND PWATS
THAT SPIKE OVER 1.0 INCH BY 12Z. GIVEN THE LESS THAN SPECTACULAR
FORCING...EXPECT A SOLID NUMEROUS/SCT COVERAGE OF LIGHT SHOWERS THIS
MORNING WITHIN THE ARC.

PRECIPITATION MAY REACH DTW BY 12Z.

12-19Z...NAM AND RAP SOLUTIONS DIVERGE AT THIS POINT ON TWO MAIN
POINTS...1. TIMING OF LEAD 700-500 DEFORMATION SURGE AND 2.
PRECIPITATION POTENTIAL WITHIN THIS ARC DURING THIS TIMEFRAME. RAP
IS FASTER/BULLISH ON PRECIPITATION WHILE THE NAM LAGS CONSIDERABLY.
GFS IS A COMPROMISE WITH FASTER TIMING...BUT MUCH LESS ON THE QPF.
TYPICALLY WOULD FAVOR THE BULLISH QPF AMOUNTS GIVEN OUTSTANDING
COLUMN SATURATION...BUT LACK OF DYNAMICS LEAVES ONE UNEASY. THE
DECIDING FACTOR HERE WILL BE OVERALL LACK OF LAPSE RATES AND
INSTABILITY AND FOR THAT REASON WILL SHAPE THE FORECAST WITH LOWER
QPF AMOUNTS IN LIGHTER SHOWER ACTIVITY...AN AVERAGED .05 THROUGH THE
M 59 CORRIDOR.

LIGHT SHOWER ACTIVITY MAY REACH PTK BY...1330Z.
                                FNT BY...1430Z.
     STALLING OUT JUST SOUTH OF MBS BY...16Z.

19-00Z...BAROCLINICITY IS LOW BUT NON-EXISTENT WITH THIS SYSTEM. IN
FACT...NAM IS SUGGESTING THAT A FRESH 850MB THETA E PLUME WILL
ADVECT STRAIGHT NORTHWARD...PUSHING INTO MUCH OF SOUTHEASTERN
MICHIGAN AFTER 18Z. GFS/NAM BOTH IN AGREEMENT THE CENTER OF 500MB
VORTICITY WILL LIFT ALONG THE WESTERN EDGE OF THIS THETA E GRADIENT
INTO FAR SOUTHEASTERN LOWER MICHIGAN BETWEEN 21-00Z. INTEGRITY OF
WARM FRONTAL FORCING AND THERMAL GRADIENTS ARE NOT IDEAL BUT MASS
ADJUSTMENTS ALONG IMMEDIATE NORTHWEST FLANK OF VORT MAX SHOULD CARVE
OUT A RESPONSE. NAM IS ON POINT WITH 850-500MB DEFORMATION
ORGANIZATION WHICH REPRESENTS THE SECOND SPIRAL DISCUSSED EARLIER.
THE BEST FORCING IS EXPECTED TO OCCUR ACROSS THE FAR EASTERN CWA
FROM MONROE UP THROUGH ST CLAIR COUNTIES. THIS FORCING MAY RESULT IN
A SOLID .2 INCHES OF QPF. ACCOUNTED FOR THIS WITH CATEGORICAL POPS
IN THOSE AREAS. ELEVATED THUNDER CHANCES APPEAR MINIMAL AND
RELEGATED TO EXTREME SOUTHEASTERN CWA BETWEEN 19-00Z...NEGATIVE
SHOWALTER INDICES HERE IN SEMICH ARE ALL POSITIVE...LOWERED THE
CHANCES ACROSS THE BOARD.

00-12Z...LIGHT SHOWERS AND/OR DRIZZLE MAY PERSIST ACROSS EXTREME
EASTERN AREAS/ST CLAIR COUNTY THROUGH 3-6Z TONIGHT WITH DEFORMATION
AXIS EVENTUALLY PEELING EASTWARD. FLOW TRAJECTORY MAY KEEP SHOWERS
JUST EAST OF THE CWA OVER PORTIONS OF CANADA THROUGH THE REMAINDER
OF THE NIGHT. EXPECT A GRUNGY AIRMASS TONIGHT WITH CLOUDS AND
POSSIBLY SOME FOG. NIL TEMPERATURE ADVECTION TONIGHT...SUPPORTS A
HIGH CONFIDENCE MIN T FORECAST RIGHT AROUND 50 DEGREES.

LONG TERM... MONDAY THROUGH SATURDAY

TODAY`S WAVE WILL DEPART TO THE EAST BY MONDAY MORNING AND LEAVE SE
MICHIGAN BETWEEN IT AND A COLD FRONT MOVING SLOWLY THROUGH THE
WESTERN GREAT LAKES. THE PARENT SURFACE LOW IS SHOWN IN THE MODEL
SOLUTIONS TO BE OVER THE FAR NORTHERN REACHES OF HUDSON BAY LEAVING
THE FRONT TO STALL AND WEAKEN OVER NORTHERN LOWER MICHIGAN. WE WILL
ALSO BE COUNTING ON BROAD SURFACE LOW PRESSURE DEVELOPMENT OVER THE
PLAINS TO HELP WASH OUT THE FRONT WITH INCREASING LARGE SCALE
GRADIENT FLOW OVER THE GREAT LAKES. THIS LOOKS LIKE A GOOD BET DUE
TO STRONG UPPER LEVEL HEIGHT FALLS OVER THE ROCKIES INITIATED BY A
POWERFUL JET MOVING INLAND FROM THE PACIFIC NORTHWEST. SATELLITE
IMAGERY THIS MORNING SHOWS THIS JET STRUCTURE NICELY WHICH THE
MODELS THEN RAMP UP TO ABOUT 150 KNOTS BY 12Z MONDAY AS IT DIGS INTO
THE ROCKIES. THESE DEVELOPMENTS IN THE LARGE SCALE PATTERN WILL PUT
A STOP TO THE EASTWARD ADVANCEMENT OF THE FRONT IN THE GREAT LAKES
AND EVENTUALLY LEAD TO ITS DECAY. EXPECT THAT ALL BUT POSSIBLY THE
TRI CITIES WILL REMAIN DRY AS A RESULT BEFORE A SLUG OF GULF
MOISTURE IS INDICATED MOVING IN MONDAY NIGHT. DEPICTIONS OF LOW TO
MID LEVEL THETA-E FIELDS SHOW THIS MOISTURE PATTERN TO BE A FRAGMENT
OF A BETTER ORGANIZED MOISTURE AXIS TAKING SHAPE OVER THE PLAINS.
GIVEN THE LIMITED PREDICTABILITY, IT IS BEST TO HOLD OFF ON ANY
EXPANSION OF POPS OUTSIDE OF THE TRI CITIES AND NORTHERN THUMB THAT
COULD CONTINUE TO BE AFFECTED BY MOISTURE REMNANTS FROM THE COLD
FRONT.

MODEL SOLUTIONS CONTINUE TO LOOK REASONABLE THROUGH TUESDAY WITH
SOUTHWEST FLOW INCREASING WHICH, ALONG WITH THE BUILDING UPPER RIDGE
OVER THE OHIO VALLEY, WILL CARRY TEMPERATURES WELL INTO THE 70S
DURING THE AFTERNOON. THERE ARE MIXED SIGNALS IN THE MOISTURE FIELDS
AMONGST THE NAM, GFS, AND ECMWF BUT ONLY WITH REGARD TO CLOUD COVER
RATHER THAN RAIN CHANCES. EVEN IF THERE IS SOME MID CLOUD LEFT TO
SCOUR OUT DURING THE DAY, EXPECT ENOUGH SURFACE HEATING TO REACH
GUIDANCE HIGHS IN THE UPPER 70S WITH 80 EVEN BEING A REASONABLE
UPPER END OF THE RANGE OVER THE INTERIOR OF LOWER MICHIGAN
SUFFICIENTLY INLAND FROM THE SHORELINES. MODEL SOUNDINGS INDICATE A
TYPICALLY MIXED BOUNDARY LAYER UP TO ABOUT 850 MB WHERE TEMPERATURE
IN THE 12 TO 14C RANGE WILL BE FAVORABLE FOR THE WARMING TREND.

IT WAS TEMPTING TO GO MORE BULLISH ON MAX TEMPS WEDNESDAY AS WELL,
BUT EVIDENCE OF BACKING SURFACE WIND SUGGESTS CAUTION. MODEL
DEPICTIONS OF THE UPPER TROUGH DIGGING TOWARD THE 4 CORNERS REGION
LOOK SOLID DURING THAT TIME PERIOD. THIS WILL SET UP AN EXTREMELY
SHARP BAROCLINIC ZONE FROM THE SOUTHERN HIGH PLAINS INTO UPPER
MICHIGAN. WHILE THE FRONT WILL REMAIN TO OUR WEST, A GREATER
EASTERLY SURFACE WIND COMPONENT WILL BRING LAKE AGGREGATE COOLING
FARTHER INLAND COMPARED TO TUESDAY. THIS WILL KEEP MAX TEMPS IN THE
70S FOR ALL BUT THE VERY INTERIOR SECTIONS OF LOWER MICHIGAN AND
EVEN IN THE 60S NEAR THE SHORELINES.

FOR THE END OF THE WEEK, THE GFS HAS MADE A CONSIDERABLE WESTWARD
ADJUSTMENT ON ITS SOLUTION FOR THE POSITION OF THE CLOSED LOW
THURSDAY INTO FRIDAY JOINING THE ECMWF AND CANADIAN IN A GENERAL
CLUSTER OF SOLUTIONS OVER THE CENTRAL PLAINS. THIS ADDS SOME
CONFIDENCE TO THE IDEA THAT SE MICHIGAN WEATHER WILL BE INFLUENCED
MORE BY THE UPPER LEVEL RIDGE PORTION OF THE DEVELOPING OMEGA
BLOCK OVER THE EASTERN HALF OF THE COUNTRY.

MARINE...

GENTLE TO MODERATE SOUTHEAST FLOW AND SIGNIFICANT WAVE HEIGHTS
AVERAGING 2 FEET OR LESS WILL PERSIST THROUGH MONDAY NIGHT BEFORE
SOUTHERLY FLOW RAMPS UP IN ADVANCE OF AN APPROACHING COLD FRONT. AN
ISOLATED THUNDERSTORM OR TWO WILL BE POSSIBLE OVER LAKE SAINT CLAIR
AND THE MICHIGAN WATERS OF LAKE ERIE AS SHOWERS SPREAD ACROSS THE
WATERS ON SUNDAY WITH MORE WIDESPREAD THUNDER POSSIBLE BY MIDWEEK.

&&

.DTX WATCHES/WARNINGS/ADVISORIES...

MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MI WATERS OF LAKE ERIE...NONE.

&&

$$

AVIATION.....CB
SHORT TERM...CB
LONG TERM....BT
MARINE.......CB


YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).










AREA FORECAST DISCUSSION

NWS MARQUETTE MI

 506 AM EDT SUN APR 28 2013

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 503 AM EDT SUN APR 28 2013

WV IMAGERY AND RUC ANALYSIS INDICATED ZONAL FLOW FROM THE PACIFIC NW
TO THE NRN GREAT LAKES. A SHORTWAVE TROUGH AND ASSOCIATED SFC LOW
WAS MOVING THROUGH ERN SASK INTO MANITOBA WITH A TROUGH EXTENDING TO
THE CNTRL DAKOTAS. AHEAD OF THE TROUGH...SSW FLOW WAS INCREASING
OVER THE UPPER MS VALLEY AND NRN GREAT LAKES. WITH THE DRY AIRMASS
BELOW 700 MB...PER 00Z INL SOUNDING...WAA AHEAD OF THE TROUGH WAS
BRINGING MAINLY MID CLOUDS AND SOME VIRGA OR SPRINKLES INTO NRN MN.
ALTHOUGH DEWPOINTS HAD CLIMBED INTO THE MID 40S SRN AND CNTRL
MN...CIRCULATION AROUND THE LOW PRESSURE SYSTEM OVER SRN IL HAD
PREVENTED MORE ABUNDANT GULF MOISTURE FROM MOVING INTO THE REGION.

EXPECT THAT SUNSHINE AND MIXING TO 850-800 MB (850 MB TEMPS FROM 7C
TO 9C) WILL REULS IN MAX READINGS IN THE MID AND UPPER 60S EAST AND
LOWER 70S WEST. SRLY FLOW OFF OF LAKE MICHIGAN WILL KEEP TEMPS
CLOSER TO 50.

AS THE SASKATCHEWAN LOW MOVES TO HUDSON BAY...IT WILL DRAG A COLD
FRONT INTO THE NRN GREAT LAKES TONIGHT. LOW LEVEL CONV NEAR THE
FRONT COMBINED WITH A WEAK SHORTWAVE MOVING OUT OF THE NRN PLAINS
WILL BE ENOUGH TO SUPPORT A BAND OF SHOWERS INTO UPPER MICHIGAN. THE
MODELS WERE IN GOOD AGREEMENT WITH THE FRONT AND PCPN BAND TRENDING
SLIGHTLY SLOWER. THE PCPN IS EXPECTED TO MOVE INTO THE WEST THIS
EVENING AND OVER THE CNTRL AND EAST OVERNIGHT. WITH ONLY WEAK
MID/UPPER LEVEL FORCING AND LIMITED MOISTURE INFLOW...OVERALL PCPN
AMOUNTS WILL BE LIGHT GENERALLY AOB 0.25 INCH...PER SREF PROB AND
CONSENSUS QPF. MDLS SUGGEST THAT ANY INSTABILITY TO SUPPORT TSRA WILL
REMAIN MAINLY TO THE S OF THE CWA.

.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 503 AM EDT SUN APR 28 2013

BEST CONFIDENCE INTO WEDNESDAY...WITH MUCH REDUCED FORECAST
CONFIDENCE AFTER THAT. PUT PRIMARY EFFORTS/TIME INTO SHORTER TERM
GRIDS GIVEN FLOODING PROBLEMS THAT WILL BE MORE CONFINED TO SHORTER
TERM.

FOR MON...EXPECT A WEAK SFC TROUGH/COLD FRONT TO PUSH
THROUGH...KEEPING SFC TEMPS A LITTLE COOLER THAN YESTERDAY OR TODAY.
UP TO AROUND A QUARTER INCH OF QPF IS EXPECTED MON...BUT AT THE SAME
TIME MELTING OF THE SNOW PACK IS REDUCED BY EXTRA CLOUD COVER AND
COOLER TEMPS /ESPECIALLY NEAR LAKE SUPERIOR/...SO THESE TWO FACTORS
MAY CANCEL EACH OTHER OUT...STILL RESULTING IN A DECENT MELT
DAY...BUT THIS IS DIFFICULT TO DETERMINE.

TEMPORARY COOL DOWN MON COMES TO YET ANOTHER END WITH 60S AND 70
HIGH TEMPS OVER MUCH OF THE AREA TUE AS 850MB TEMPS INCREASE TO
AROUND 14C BY 18Z TUE. THESE WARMER TEMPS COME AHEAD OF ANOTHER
SYSTEM THAT WILL MOVE N OF LAKE SUPERIOR...WHICH BRINGS A COLD FRONT
ACROSS THE CWA LATE TUE INTO TUE NIGHT. MODELS ARE EVEN SHOWING
SOME CAPE ALONG AND AHEAD OF THE COLD FRONT...WHICH MAY RESULT IN
THUNDERSTORM ACTIVITY. THE HEAVIEST RAINFALL IS MAINLY FOCUSED OVER
THE ERN HALF OFF UPPER MI...AND WILL BE SOMETHING TO WATCH WITH
RESPECT TO CONTINUED FLOOD THREAT.

OTHER THAN THOSE SYSTEM...MODELS IN THE FARTHER EXTENDED SHOW LARGE
DISAGREEMENT IN THERMAL FIELDS...SO A WIDE VARIETY OF TEMPS ARE
POSSIBLE. ALTHOUGH MODELS DO SHOW GOOD GENERAL AGREEMENT...THE EXACT
PLACEMENT OF THE UPPER LOW THEY SHOW OVER THE CENTRAL CONUS BY FRI
IS ESSENTIAL FOR TEMPS/PRECIP. WILL JUST USE A CONSENSUS OF MODELS
FOR THIS PERIOD GIVEN THE UNCERTAINTY.
&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 124 AM EDT SUN APR 28 2013

EXPECT VFR CONDITIONS TO PREVAIL THIS TAF PERIOD WITH RELATIVELY DRY
AIRMASS DOMINATING IN SW FLOW ARND HI PRES OVER NEW ENGLAND. NOT OUT
OF THE QUESTION THERE COULD BE SOME FOG...MAINLY AT SAW WHERE SFC
DEWPTS ARE HIER...BUT LEFT OUT OF THE FCST FOR NOW AS THE WIND MAY
REMAIN HI ENUF TO LIMIT DIURNAL TEMP DROP. AS THE PRES GRADIENT
TIGHTENS BTWN THIS HI AND FALLING MSLP IN THE PLAINS...EXPECT SOME
LLWS TO DVLP AT CMX/IWD OVERNGT. THE ONSET OF DAYTIME HEATING BY
MID/LATE SUN MRNG WL MIX OUT THE HIER WINDS AND ALLOW GUSTY SW WINDS
TO REACH THE SFC. SOME -SHRA WL ARRIVE AT IWD/CMX AFT 00Z AHEAD OF
AN INCOMING COLD FNT...BUT LIMITED MSTR RETURN WL LIMIT PCPN
INTENSITY AND THE POTENTIAL FOR CONDITIONS LOWER THAN VFR.
&&

.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 503 AM EDT SUN APR 28 2013

WINDS SHOULD STAY BELOW 25KTS THROUGH THE PERIOD WITH NO GALES IN
SIGHT. NO STRONG SYSTEMS WILL BE COMING CLOSE TO THE AREA...SO NO
STRONG PRESSURE GRADIENTS ARE EXPECTED.
&&

.HYDROLOGY...
ISSUED AT 503 AM EDT SUN APR 28 2013

SAW GOOD MELTING YESTERDAY AFTERNOON WITH HIGH TEMPS IN THE 60S AND
70S AFTER THE SNOW PACK WARMED UP FROM SUB-FREEZING TEMPS THE NIGHT
BEFORE. SINCE TEMPS ARE WELL ABOVE FREEZING TONIGHT...AND HIGH TEMPS
TODAY WILL BE SIMILAR TO YESTERDAY BUT WITH SLIGHTLY HIGHER DEW
POINTS...WE SHOULD SEE EVEN BETTER MELTING FOR A LONGER PERIOD OF
TIME THAN YESTERDAY. PLACES WITH SNOWPACK REMAINING WILL SEE RAPID
AND EXTENSIVE MELTING TODAY...CAUSING RUNOFF INTO TONIGHT INTO AREA
STREAMS. RIVERS OF PARTICULAR CONCERN AFTER THE MELTING TODAY WILL
BE THE TRAP ROCK RIVER...THE STURGEON RIVER OF BARAGA/HOUGHTON
COUNTIES...AND THE PESHEKEE RIVER. RUNOFF MAY NOT PEAK UNTIL
TONIGHT/MONDAY...AND EVEN GET FORTIFIED BY ADDITIONAL MELTING AND
EVEN SOME RAIN ON MONDAY. RAINFALL AMOUNTS WILL GENERALLY BE AROUND
A QUARTER OF AN INCH...OR POSSIBLY MORE IN A FEW AREAS AND WILL
START LATE THIS EVENING INTO MONDAY. ANY RAIN WILL ONLY ADD TO
HYDROLOGIC CONCERNS...AND WILL HAVE TO PAY CLOSE ATTENTION TO PRECIP
AMOUNTS MONDAY. FURTHER CHANCES OF PRECIPITATION ARE EXPECTED AS
COLD FRONT WORKS THROUGH ON TUESDAY...WHEN THERE MAY BE
THUNDERSTORMS TOO. OTHERWISE...ADDITIONAL CHANCES OF PRECIPITATION
ARE POSSIBLE THE REST OF THE WEEK AS FRONT STAYS CLOSE BY TO THE
AREA.

MELTING SCENARIOS REMAIN THE BIGGEST CONFIDENCE REDUCERS AT THIS
POINT...AND IF THE RIVER FORECAST CENTER HAS TO INCREASE THE MELT
FACTOR CORRECTION GOING INTO THE RIVER MODELS THE FORECASTS WILL
LIKELY END UP QUITE A BIT HIGHER. ONCE PLACE WHERE THE MELT
CORRECTION FACTOR WAS INCREASED FOR FOR THE MEN RIVER FORECAST GROUP
/RIVERS THAT DRAIN INTO THE MENOMINEE RIVER/...WHICH RESULTED IN
MUCH INCREASED FORECASTS UP TO NEAR RECORD STAGE AT PESHEKEE AND
MODERATE FLOOD STAGE DOWNSTREAM ON THE MICHIGAMME RIVER NEAR
REPUBLIC/WITCH LAKE. WFO SURVEY OF THE PESHEKEE RIVER REVEALED THICK
ICE COVERING MOST OF THE RIVER AND THICK ICE COVER MOST OF LAKE
MICHIGAMME WHICH THE PESHEKEE DRAINS INTO. ICE JAMS COULD CAUSE
SIGNIFICANT PROBLEMS AS THE RIVER RISES LATE TODAY INTO MONDAY. OF
COURSE...MAIN STEM RIVERS ARE NOT THE ONLY HAZARD...AS WE ARE ALSO
LOOKING AT THREAT OF AREAL FLOOD PROBLEMS WITH SMALLER
CREEKS/STREAMS AND STANDING WATER ON ROADS. FOR FURTHER
DETAILS...SEE THE HYDROLOGIC OUTLOOK /ESF/ AND THE LATEST RIVER
WATCHES /FFAMQT/.
&&

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

$$

SHORT TERM...JLB
LONG TERM...TITUS
AVIATION...KC
MARINE...JLB
HYDROLOGY...TITUS







AREA FORECAST DISCUSSION

NWS DETROIT/PONTIAC MI

 356 AM EDT SUN APR 28 2013

.SHORT TERM...TODAY AND TONIGHT

08-12Z...AN AMPLITUDE INCREASE OF THE EASTERN NORTH AMERICA LONGWAVE
RIDGE WILL BE THE FORCING MECHANISM WHICH WILL DRAW THE SOUTHERN IL
PV ANOMALY NORTHWARD INTO MICHIGAN TODAY. TWO SPIRALS OF 700-500MB
DEFORMATION WILL EMANATE NORTHWARD AWAY FROM THE PARENT VORTICITY
MAXIMUM THE FIRST OF WHICH WILL LIFT ACROSS THE MICHIGAN/OHIO
STATELINE AFTER 9Z. THIS IS ADVERTISED BY LINEAR EXTRAPOLATION FROM
RADAR MOSAIC AND TIMING OF NAM/RAP. DEFORMATION FORCING WILL BE
COASTING INTO THE STATE...WEAKENING DRAMATICALLY ACCORDING TO NWP
PROJECTIONS. FEEL GOOD ABOUT THIS GIVEN INCREASING DISTANCE FROM
VORTICITY MAXIMUM...WARMING CLOUD TOPS IN LATEST IR...AND SPOTTY
COVERAGE IN AREA RADAR IMAGERY. WHAT THE INBOUND AIRMASS WILL HAVE
IS GOOD MOISTURE QUALITY...SATURATION UPWARDS OF 30 KFT AND PWATS
THAT SPIKE OVER 1.0 INCH BY 12Z. GIVEN THE LESS THAN SPECTACULAR
FORCING...EXPECT A SOLID NUMEROUS/SCT COVERAGE OF LIGHT SHOWERS THIS
MORNING WITHIN THE ARC.

PRECIPITATION MAY REACH DTW BY 12Z.

12-19Z...NAM AND RAP SOLUTIONS DIVERGE AT THIS POINT ON TWO MAIN
POINTS...1. TIMING OF LEAD 700-500 DEFORMATION SURGE AND 2.
PRECIPITATION POTENTIAL WITHIN THIS ARC DURING THIS TIMEFRAME. RAP
IS FASTER/BULLISH ON PRECIPITATION WHILE THE NAM LAGS CONSIDERABLY.
GFS IS A COMPROMISE WITH FASTER TIMING...BUT MUCH LESS ON THE QPF.
TYPICALLY WOULD FAVOR THE BULLISH QPF AMOUNTS GIVEN OUTSTANDING
COLUMN SATURATION...BUT LACK OF DYNAMICS LEAVES ONE UNEASY. THE
DECIDING FACTOR HERE WILL BE OVERALL LACK OF LAPSE RATES AND
INSTABILITY AND FOR THAT REASON WILL SHAPE THE FORECAST WITH LOWER
QPF AMOUNTS IN LIGHTER SHOWER ACTIVITY...AN AVERAGED .05 THROUGH THE
M 59 CORRIDOR.

LIGHT SHOWER ACTIVITY MAY REACH PTK BY...1330Z.
                                FNT BY...1430Z.
     STALLING OUT JUST SOUTH OF MBS BY...16Z.

19-00Z...BAROCLINICITY IS LOW BUT NON-EXISTENT WITH THIS SYSTEM. IN
FACT...NAM IS SUGGESTING THAT A FRESH 850MB THETA E PLUME WILL
ADVECT STRAIGHT NORTHWARD...PUSHING INTO MUCH OF SOUTHEASTERN
MICHIGAN AFTER 18Z. GFS/NAM BOTH IN AGREEMENT THE CENTER OF 500MB
VORTICITY WILL LIFT ALONG THE WESTERN EDGE OF THIS THETA E GRADIENT
INTO FAR SOUTHEASTERN LOWER MICHIGAN BETWEEN 21-00Z. INTEGRITY OF
WARM FRONTAL FORCING AND THERMAL GRADIENTS ARE NOT IDEAL BUT MASS
ADJUSTMENTS ALONG IMMEDIATE NORTHWEST FLANK OF VORT MAX SHOULD CARVE
OUT A RESPONSE. NAM IS ON POINT WITH 850-500MB DEFORMATION
ORGANIZATION WHICH REPRESENTS THE SECOND SPIRAL DISCUSSED EARLIER.
THE BEST FORCING IS EXPECTED TO OCCUR ACROSS THE FAR EASTERN CWA
FROM MONROE UP THROUGH ST CLAIR COUNTIES. THIS FORCING MAY RESULT IN
A SOLID .2 INCHES OF QPF. ACCOUNTED FOR THIS WITH CATEGORICAL POPS
IN THOSE AREAS. ELEVATED THUNDER CHANCES APPEAR MINIMAL AND
RELEGATED TO EXTREME SOUTHEASTERN CWA BETWEEN 19-00Z...NEGATIVE
SHOWALTER INDICES HERE IN SEMICH ARE ALL POSITIVE...LOWERED THE
CHANCES ACROSS THE BOARD.

00-12Z...LIGHT SHOWERS AND/OR DRIZZLE MAY PERSIST ACROSS EXTREME
EASTERN AREAS/ST CLAIR COUNTY THROUGH 3-6Z TONIGHT WITH DEFORMATION
AXIS EVENTUALLY PEELING EASTWARD. FLOW TRAJECTORY MAY KEEP SHOWERS
JUST EAST OF THE CWA OVER PORTIONS OF CANADA THROUGH THE REMAINDER
OF THE NIGHT. EXPECT A GRUNGY AIRMASS TONIGHT WITH CLOUDS AND
POSSIBLY SOME FOG. NIL TEMPERATURE ADVECTION TONIGHT...SUPPORTS A
HIGH CONFIDENCE MIN T FORECAST RIGHT AROUND 50 DEGREES.

&&

.LONG TERM... MONDAY THROUGH SATURDAY

TODAY`S WAVE WILL DEPART TO THE EAST BY MONDAY MORNING AND LEAVE SE
MICHIGAN BETWEEN IT AND A COLD FRONT MOVING SLOWLY THROUGH THE
WESTERN GREAT LAKES. THE PARENT SURFACE LOW IS SHOWN IN THE MODEL
SOLUTIONS TO BE OVER THE FAR NORTHERN REACHES OF HUDSON BAY LEAVING
THE FRONT TO STALL AND WEAKEN OVER NORTHERN LOWER MICHIGAN. WE WILL
ALSO BE COUNTING ON BROAD SURFACE LOW PRESSURE DEVELOPMENT OVER THE
PLAINS TO HELP WASH OUT THE FRONT WITH INCREASING LARGE SCALE
GRADIENT FLOW OVER THE GREAT LAKES. THIS LOOKS LIKE A GOOD BET DUE
TO STRONG UPPER LEVEL HEIGHT FALLS OVER THE ROCKIES INITIATED BY A
POWERFUL JET MOVING INLAND FROM THE PACIFIC NORTHWEST. SATELLITE
IMAGERY THIS MORNING SHOWS THIS JET STRUCTURE NICELY WHICH THE
MODELS THEN RAMP UP TO ABOUT 150 KNOTS BY 12Z MONDAY AS IT DIGS INTO
THE ROCKIES. THESE DEVELOPMENTS IN THE LARGE SCALE PATTERN WILL PUT
A STOP TO THE EASTWARD ADVANCEMENT OF THE FRONT IN THE GREAT LAKES
AND EVENTUALLY LEAD TO ITS DECAY. EXPECT THAT ALL BUT POSSIBLY THE
TRI CITIES WILL REMAIN DRY AS A RESULT BEFORE A SLUG OF GULF
MOISTURE IS INDICATED MOVING IN MONDAY NIGHT. DEPICTIONS OF LOW TO
MID LEVEL THETA-E FIELDS SHOW THIS MOISTURE PATTERN TO BE A FRAGMENT
OF A BETTER ORGANIZED MOISTURE AXIS TAKING SHAPE OVER THE PLAINS.
GIVEN THE LIMITED PREDICTABILITY, IT IS BEST TO HOLD OFF ON ANY
EXPANSION OF POPS OUTSIDE OF THE TRI CITIES AND NORTHERN THUMB THAT
COULD CONTINUE TO BE AFFECTED BY MOISTURE REMNANTS FROM THE COLD
FRONT.

MODEL SOLUTIONS CONTINUE TO LOOK REASONABLE THROUGH TUESDAY WITH
SOUTHWEST FLOW INCREASING WHICH, ALONG WITH THE BUILDING UPPER RIDGE
OVER THE OHIO VALLEY, WILL CARRY TEMPERATURES WELL INTO THE 70S
DURING THE AFTERNOON. THERE ARE MIXED SIGNALS IN THE MOISTURE FIELDS
AMONGST THE NAM, GFS, AND ECMWF BUT ONLY WITH REGARD TO CLOUD COVER
RATHER THAN RAIN CHANCES. EVEN IF THERE IS SOME MID CLOUD LEFT TO
SCOUR OUT DURING THE DAY, EXPECT ENOUGH SURFACE HEATING TO REACH
GUIDANCE HIGHS IN THE UPPER 70S WITH 80 EVEN BEING A REASONABLE
UPPER END OF THE RANGE OVER THE INTERIOR OF LOWER MICHIGAN
SUFFICIENTLY INLAND FROM THE SHORELINES. MODEL SOUNDINGS INDICATE A
TYPICALLY MIXED BOUNDARY LAYER UP TO ABOUT 850 MB WHERE TEMPERATURE
IN THE 12 TO 14C RANGE WILL BE FAVORABLE FOR THE WARMING TREND.

IT WAS TEMPTING TO GO MORE BULLISH ON MAX TEMPS WEDNESDAY AS WELL,
BUT EVIDENCE OF BACKING SURFACE WIND SUGGESTS CAUTION. MODEL
DEPICTIONS OF THE UPPER TROUGH DIGGING TOWARD THE 4 CORNERS REGION
LOOK SOLID DURING THAT TIME PERIOD. THIS WILL SET UP AN EXTREMELY
SHARP BAROCLINIC ZONE FROM THE SOUTHERN HIGH PLAINS INTO UPPER
MICHIGAN. WHILE THE FRONT WILL REMAIN TO OUR WEST, A GREATER
EASTERLY SURFACE WIND COMPONENT WILL BRING LAKE AGGREGATE COOLING
FARTHER INLAND COMPARED TO TUESDAY. THIS WILL KEEP MAX TEMPS IN THE
70S FOR ALL BUT THE VERY INTERIOR SECTIONS OF LOWER MICHIGAN AND
EVEN IN THE 60S NEAR THE SHORELINES.

FOR THE END OF THE WEEK, THE GFS HAS MADE A CONSIDERABLE WESTWARD
ADJUSTMENT ON ITS SOLUTION FOR THE POSITION OF THE CLOSED LOW
THURSDAY INTO FRIDAY JOINING THE ECMWF AND CANADIAN IN A GENERAL
CLUSTER OF SOLUTIONS OVER THE CENTRAL CENTRAL PLAINS. THIS ADDS SOME
CONFIDENCE TO THE IDEA THAT SE MICHIGAN WEATHER WILL BE INFLUENCED
MORE BY THE UPPER LEVEL RIDGE PORTION OF THE DEVELOPING OMEGA BLOCK
OVER THE EASTERN HALF OF THE COUNTRY.

&&

.MARINE...

GENTLE TO MODERATE SOUTHEAST FLOW AND SIGNIFICANT WAVE HEIGHTS
AVERAGING 2 FEET OR LESS WILL PERSIST THROUGH MONDAY NIGHT BEFORE
SOUTHERLY FLOW RAMPS UP IN ADVANCE OF AN APPROACHING COLD FRONT. AN
ISOLATED THUNDERSTORM OR TWO WILL BE POSSIBLE OVER LAKE SAINT CLAIR
AND THE MICHIGAN WATERS OF LAKE ERIE AS SHOWERS SPREAD ACROSS THE
WATERS ON SUNDAY WITH MORE WIDESPREAD THUNDER POSSIBLE BY MIDWEEK.

&&

.AVIATION...ISSUED 1157 PM EDT SAT APR 27 2013

//DISCUSSION...

VFR CONDITIONS WILL GIVE WAY TO LOWER CIGS LATE TONIGHT INTO SUNDAY
AS LOW PRESSURE LIFTS INTO THE OHIO VALLEY. SCATTERED SHOWERS WILL
SPREAD NORTH INTO THE AREA WITH IFR/LIFR CIGS DEVELOPING. VLIFR WILL
EVEN BE POSSIBLE LATE IN THE FORECAST PERIOD AS THE LOW DRIFTS OVER
THE AREA AND PROVIDE BEST POOLING OF LOW LEVEL MOISTURE.

FOR DTW...VFR CONDITIONS WILL TRANSITION TO MVFR SUNDAY MORNING AND
THEN IFR AFTERNOON/EVENING AS SHOWERS SPREAD IN FROM THE SOUTH. THE
SHOWERS WILL PERSIST OFF/ON THROUGHOUT THE DAY...BUT WILL DIMINISH
AFTER 00Z AS CIGS POSSIBLY FALL TO LIFR WITH THE PASSAGE OF THE LOW.

//DTW THRESHOLD THREATS...

* HIGH CONFIDENCE IN CEILINGS BELOW 5000 FEET BY 11Z-13Z.

* LOW CONFIDENCE IN CEILINGS DOWN TO 200 FEET AFTER 00Z SUNDAY.

&&

.DTX WATCHES/WARNINGS/ADVISORIES...

MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MI WATERS OF LAKE ERIE...NONE.

&&

$$

SHORT TERM...CB
LONG TERM....BT
MARINE.......CB
AVIATION.....DG


YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).









AREA FORECAST DISCUSSION...UPDATED

NWS ST LOUIS MO

 912 PM CDT MON APR 29 2013

.UPDATE...
ISSUED AT 912 PM CDT MON APR 29 2013

HAVE REMOVED RAIN CHANCES FOR TONIGHT. THUNDERSTORMS HAVE DEVELOPED
IN THE LAST 1-2 HOURS WELL NORTH OF THE CWA IN NORTH CENTRAL AND
NORTHEAST IOWA ALONG A WARM FRONT. CHANCES FOR RAIN OVER NORTHEAST
MO/WEST CENTRAL IL LOOK TO BE DIMINISHING AS 00Z 700MB UPPER
ANALYSIS SHOWED WEAK WARM AIR ADVECTION MOVING INTO NORTHERN MO.
RAP FORECAST SOUNDING AT KUIN DOES SHOW WARMING BETWEEN 900-700MB
OVERNIGHT WITH WEAKENING CAPE.

LITTLE CHANGE NEEDED TO THE REST OF THE FORECAST AS GRADIENT WINDS
WILL STAY UP ENOUGH TO KEEP TEMPERATURES FROM FALLING BELOW GOING
LOWS.

BRITT

&&

.SHORT TERM...(THROUGH LATE TONIGHT)
ISSUED AT 256 PM CDT MON APR 29 2013

PRIMARY WEATHER CONCERN FOR TONIGHT IS THE POSSIBILITY OF CONVECTION
ACROSS NORTHERN MISSOURI AND WEST CENTRAL ILLINOIS.  RUC CONTINUES
TO FORECAST COPIOUS AMOUNTS OF CAPE SOUTH OF A Q-STATIONARY FRONT
EXTENDING THROUGH NORTHEAST KANSAS INTO SOUTHEAST NEBRASKA AND
WESTERN IOWA LATE THIS AFTERNOON.  GREATEST VALUES EXCEED 4000 J/KG
ACROSS PARTS OF WESTERN AND CENTRAL MISSOURI.  HOWEVER...RUC ALSO
APPEARS TO BE 3 TO 5 DEGREES TOO MOIST ON DEWPOINT FORECASTS LATER
THIS AFTERNOON INTO THE EVENING WHICH WOULD DEFINITELY ACCOUNT FOR
THE GIHEMOUS CAPE VALUES.  THAT BEING SAID...THERE IS SOME
AGITATED CU OVER SOUTH CENTRAL MISSOURI AND ONE LONE THUNDERSTORM
OVER NORTHERN ARKANSAS...SO THERE`S OBVIOUSLY SOME INSTABILITY OUT
THERE.  CURRENT THINKING IS THAT THE ISOLATED CONVECTION OVER SOUTH
CENTRAL MISSOURI WON`T MAKE IT TO OUR AREA...AND THAT CONVECTION
WILL FIRE CLOSER TO THE BAROCLINIC ZONE IN NEBRASKA LATE THIS
AFTERNOON/EARLY EVENING AND RIDE UP ACROSS IOWA.  COULD SEE THE TAIL
END OF ANY CONVECTIVE COMPLEX THAT FORMS AFFECT NORTHERN PORTIONS OF
THE CWFA SO HAVE KEPT LOW CHANCE POPS UP THERE.  OTHERWISE...SHOULD
BE MILD AND QUIET NIGHT.

CARNEY

.LONG TERM...(TUESDAY THROUGH NEXT MONDAY)
ISSUED AT 256 PM CDT MON APR 29 2013

TUESDAY THROUGH THURSDAY...CONFIDENCE MEDIUM

WELL ABOVE NORMAL TEMPERATURES ARE EXPECTED TUESDAY AND WEDNESDAY
AHEAD OF THE DIGGING TROF AND COLD FRONT. CAN`T ARGUE MUCH WITH MOS
GUIDANCE WITH HIGHS IN THE LOWER TO MIDDLE 80S AND LOWS IN THE 60S.

MODEL GUIDANCE IN GOOD AGREEMENT THAT COLD FRONT WILL WAIT UNTIL
WEDNESDAY NIGHT AND THURSDAY MORNING TO START MOVING ACROSS THE CWA.
PRECIPITATION CHANCES TO INCREASE FROM THE WEST...BUT BELIEVE A
LARGE PART OF THE CWA WILL REMAIN DRY THROUGH THURSDAY MORNING.

THIS WILL CHANGE THURSDAY AFTERNOON. THE MAIN BAND OF RAIN WILL EDGE
INTO CENTRAL AND NORTHEAST MISSOURI...WHILE CONVECTION FIRES ON THE
FRONT ITSELF ALONG AND EAST OF THE MISSISSIPPI RIVER. I AM SURE
SOMEONE IN THE MIDDLE OF THESE TWO AREAS OF PRECIPITATION MAY REMAIN
DRY...BUT IT IS TOO FAR OUT TO GET TOO CUTE WITH POP GRADIENTS.

SHOULD BE QUITE A TEMPERATURE CONTRAST ACROSS THE CWA ON THURSDAY
WITH STEADY OR SLOWLY FALLING TEMPERATURES IN THE 40S IN THE WESTERN
CWA...TO THE LOW/MIDDLE 70S IN SOUTH CENTRAL ILLINOIS.

FRIDAY THROUGH MONDAY...CONFIDENCE LOW

MODELS ARE STILL HAVING SOME DIFFICULTY IN HOW THEY HANDLE THE TRACK
OF THE CLOSED OFF LOW LATE THIS WEEK AND WEEKEND. PREFER TO KEEP
FORECAST TREND THE SAME...ESSENTIALLY FOLLOWING HPC GUIDANCE AND 12Z
ECWMF...WITH THE CLOSED OFF LOW DEVELOPING TO OUR WEST AND SPINNING
NORTHEAST ACROSS THE MIDWEST TOWARD THE GREAT LAKES THIS WEEKEND.

MARCHED THE MAIN BAND OF RAIN EAST THURSDAY NIGHT AND FRIDAY WITH
LIKELY POPS AND THEN CONTINUED LOW CHANCE POPS FOR RAIN SHOWERS
THROUGH MONDAY AS AREA EXPECTED TO REMAIN AT LEAST IN THE
VICINITY OF THE COLD CORE SYSTEM. FORECAST RAINFALL AMOUNTS WITH
THIS SOLUTION WOULD BE ON THE ORDER OF 1 TO 1.5 INCHES FOR THE
EVENT.

TEMPERATURES STILL ON TRACK TO FALL BACK BELOW NORMAL FRIDAY AND
SATURDAY...BUT SLOWLY WARM SUNDAY AND MONDAY AS INFLUENCE OF THE
SYSTEM WAINS BY THE BEGINING OF NEXT WEEK.

NOTE...THE 12Z GFS AND GEM CAME IN QUITE A BIT FURTHER TO THE
SOUTHWEST AND MUCH SLOWER WITH THE SYSTEM...WHICH WOULD RESULT IN A
PROLONGED PERIOD OF RAIN AS THE FRONT AND TROPICAL FETCH PARK ITSELF
ACROSS THE MISSISSIPPI RIVER VALLEY FOR THE ENTIRE WEEKEND. THIS
SOLUTION WOULD YIELD WIDESPREAD RAINFALL AMOUNTS IN EXCESS OF 2
INCHES...WITH SOME LOCALS OVER 4 INCHES.

CVKING

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING)
ISSUED AT 631 PM CDT MON APR 29 2013

VFR CONDITIONS TO PREVAIL THROUGH FORECAST PERIOD. THUNDERSTORM
ACTIVITY TO REMAIN NORTH OF FORECAST AREA...SO ONLY ISSUE WILL BE
THE WINDS AND POSSIBLE LLWS TONIGHT. WINDS TO DIMINISH TO AROUND
10KTS FROM THE SOUTH THIS EVENING. OVER CENTRAL/NORTHEAST
MO...WEST CENTRAL IL...LOW LEVEL JET TO PICKUP FROM THE
SOUTHWEST...SO KEPT MENTION BEGINNING AROUND 04Z. OTHERWISE...
SOUTH WINDS TO MIX DOWN TO SURFACE AND PICKUP ALL LOCATIONS BY MID
MORNING ON TUESDAY WITH GUSTS TO AROUND 20KTS AT TIMES.

SPECIFICS FOR KSTL...VFR CONDITIONS TO PREVAIL THROUGH FORECAST
PERIOD. ONLY ISSUE WILL BE THE WINDS. WINDS TO DIMINISH TO AROUND
10KTS FROM THE SOUTH THIS EVENING. OTHERWISE...GUSTY WINDS TO MIX
DOWN TO SURFACE AND PICKUP BY 15Z TUESDAY WITH GUSTS TO AROUND
20KTS AT TIMES...BEFORE DIMINISHING ONCE AGAIN TUESDAY EVENING.
WINDS COULD VEER A BIT MORE TO THE SOUTHWEST ON TUESDAY AFFECTING
RUNWAY CONFIGURATION...SO WILL KEEP AN EYE ON IT FOR NOW.

BYRD

&&

.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&

$$

WFO LSX








AREA FORECAST DISCUSSION...UPDATED AVIATION

NWS ST LOUIS MO

 631 PM CDT MON APR 29 2013

.SHORT TERM...(THROUGH LATE TONIGHT)
ISSUED AT 256 PM CDT MON APR 29 2013

PRIMARY WEATHER CONCERN FOR TONIGHT IS THE POSSIBILITY OF CONVECTION
ACROSS NORTHERN MISSOURI AND WEST CENTRAL ILLINOIS.  RUC CONTINUES
TO FORECAST COPIOUS AMOUNTS OF CAPE SOUTH OF A Q-STATIONARY FRONT
EXTENDING THROUGH NORTHEAST KANSAS INTO SOUTHEAST NEBRASKA AND
WESTERN IOWA LATE THIS AFTERNOON.  GREATEST VALUES EXCEED 4000 J/KG
ACROSS PARTS OF WESTERN AND CENTRAL MISSOURI.  HOWEVER...RUC ALSO
APPEARS TO BE 3 TO 5 DEGREES TOO MOIST ON DEWPOINT FORECASTS LATER
THIS AFTERNOON INTO THE EVENING WHICH WOULD DEFINITELY ACCOUNT FOR
THE GIHEMOUS CAPE VALUES.  THAT BEING SAID...THERE IS SOME
AGITATED CU OVER SOUTH CENTRAL MISSOURI AND ONE LONE THUNDERSTORM
OVER NORTHERN ARKANSAS...SO THERE`S OBVIOUSLY SOME INSTABILITY OUT
THERE.  CURRENT THINKING IS THAT THE ISOLATED CONVECTION OVER SOUTH
CENTRAL MISSOURI WON`T MAKE IT TO OUR AREA...AND THAT CONVECTION
WILL FIRE CLOSER TO THE BAROCLINIC ZONE IN NEBRASKA LATE THIS
AFTERNOON/EARLY EVENING AND RIDE UP ACROSS IOWA.  COULD SEE THE TAIL
END OF ANY CONVECTIVE COMPLEX THAT FORMS AFFECT NORTHERN PORTIONS OF
THE CWFA SO HAVE KEPT LOW CHANCE POPS UP THERE.  OTHERWISE...SHOULD
BE MILD AND QUIET NIGHT.

CARNEY

.LONG TERM...(TUESDAY THROUGH NEXT MONDAY)
ISSUED AT 256 PM CDT MON APR 29 2013

TUESDAY THROUGH THURSDAY...CONFIDENCE MEDIUM

WELL ABOVE NORMAL TEMPERATURES ARE EXPECTED TUESDAY AND WEDNESDAY
AHEAD OF THE DIGGING TROF AND COLD FRONT. CAN`T ARGUE MUCH WITH MOS
GUIDANCE WITH HIGHS IN THE LOWER TO MIDDLE 80S AND LOWS IN THE 60S.

MODEL GUIDANCE IN GOOD AGREEMENT THAT COLD FRONT WILL WAIT UNTIL
WEDNESDAY NIGHT AND THURSDAY MORNING TO START MOVING ACROSS THE CWA.
PRECIPITATION CHANCES TO INCREASE FROM THE WEST...BUT BELIEVE A
LARGE PART OF THE CWA WILL REMAIN DRY THROUGH THURSDAY MORNING.

THIS WILL CHANGE THURSDAY AFTERNOON. THE MAIN BAND OF RAIN WILL EDGE
INTO CENTRAL AND NORTHEAST MISSOURI...WHILE CONVECTION FIRES ON THE
FRONT ITSELF ALONG AND EAST OF THE MISSISSIPPI RIVER. I AM SURE
SOMEONE IN THE MIDDLE OF THESE TWO AREAS OF PRECIPITATION MAY REMAIN
DRY...BUT IT IS TOO FAR OUT TO GET TOO CUTE WITH POP GRADIENTS.

SHOULD BE QUITE A TEMPERATURE CONTRAST ACROSS THE CWA ON THURSDAY
WITH STEADY OR SLOWLY FALLING TEMPERATURES IN THE 40S IN THE WESTERN
CWA...TO THE LOW/MIDDLE 70S IN SOUTH CENTRAL ILLINOIS.

FRIDAY THROUGH MONDAY...CONFIDENCE LOW

MODELS ARE STILL HAVING SOME DIFFICULTY IN HOW THEY HANDLE THE TRACK
OF THE CLOSED OFF LOW LATE THIS WEEK AND WEEKEND. PREFER TO KEEP
FORECAST TREND THE SAME...ESSENTIALLY FOLLOWING HPC GUIDANCE AND 12Z
ECWMF...WITH THE CLOSED OFF LOW DEVELOPING TO OUR WEST AND SPINNING
NORTHEAST ACROSS THE MIDWEST TOWARD THE GREAT LAKES THIS WEEKEND.

MARCHED THE MAIN BAND OF RAIN EAST THURSDAY NIGHT AND FRIDAY WITH
LIKELY POPS AND THEN CONTINUED LOW CHANCE POPS FOR RAIN SHOWERS
THROUGH MONDAY AS AREA EXPECTED TO REMAIN AT LEAST IN THE
VICINITY OF THE COLD CORE SYSTEM. FORECAST RAINFALL AMOUNTS WITH
THIS SOLUTION WOULD BE ON THE ORDER OF 1 TO 1.5 INCHES FOR THE
EVENT.

TEMPERATURES STILL ON TRACK TO FALL BACK BELOW NORMAL FRIDAY AND
SATURDAY...BUT SLOWLY WARM SUNDAY AND MONDAY AS INFLUENCE OF THE
SYSTEM WAINS BY THE BEGINING OF NEXT WEEK.

NOTE...THE 12Z GFS AND GEM CAME IN QUITE A BIT FURTHER TO THE
SOUTHWEST AND MUCH SLOWER WITH THE SYSTEM...WHICH WOULD RESULT IN A
PROLONGED PERIOD OF RAIN AS THE FRONT AND TROPICAL FETCH PARK ITSELF
ACROSS THE MISSISSIPPI RIVER VALLEY FOR THE ENTIRE WEEKEND. THIS
SOLUTION WOULD YIELD WIDESPREAD RAINFALL AMOUNTS IN EXCESS OF 2
INCHES...WITH SOME LOCALS OVER 4 INCHES.

CVKING

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING)
ISSUED AT 631 PM CDT MON APR 29 2013

VFR CONDITIONS TO PREVAIL THROUGH FORECAST PERIOD. THUNDERSTORM
ACTIVITY TO REMAIN NORTH OF FORECAST AREA...SO ONLY ISSUE WILL BE
THE WINDS AND POSSIBLE LLWS TONIGHT. WINDS TO DIMINISH TO AROUND
10KTS FROM THE SOUTH THIS EVENING. OVER CENTRAL/NORTHEAST
MO...WEST CENTRAL IL...LOW LEVEL JET TO PICKUP FROM THE
SOUTHWEST...SO KEPT MENTION BEGINNING AROUND 04Z. OTHERWISE...
SOUTH WINDS TO MIX DOWN TO SURFACE AND PICKUP ALL LOCATIONS BY MID
MORNING ON TUESDAY WITH GUSTS TO AROUND 20KTS AT TIMES.

SPECIFICS FOR KSTL...VFR CONDITIONS TO PREVAIL THROUGH FORECAST
PERIOD. ONLY ISSUE WILL BE THE WINDS. WINDS TO DIMINISH TO AROUND
10KTS FROM THE SOUTH THIS EVENING. OTHERWISE...GUSTY WINDS TO MIX
DOWN TO SURFACE AND PICKUP BY 15Z TUESDAY WITH GUSTS TO AROUND
20KTS AT TIMES...BEFORE DIMINISHING ONCE AGAIN TUESDAY EVENING.
WINDS COULD VEER A BIT MORE TO THE SOUTHWEST ON TUESDAY AFFECTING
RUNWAY CONFIGURATION...SO WILL KEEP AN EYE ON IT FOR NOW.

BYRD
&&

.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&

$$

WFO LSX







AREA FORECAST DISCUSSION...UPDATED

NWS ST LOUIS MO

 1249 PM CDT SUN APR 28 2013

.UPDATE...
ISSUED AT 1235 PM CDT SUN APR 28 2013
MADE A FEW CHANGES TO THE REST OF THE DAY...MAINLY TO KEEP CLOUDS
HANGING IN LONGER AND TO LOWER TEMPERATURES A FEW DEGREES. THE
WESTERN EDGE OF THE CLOUDS BLEW UP WITH DIURNAL STRATO-CU
DEVELOPMENT A COUPLE OF HOURS AGO...AND IT SIMPLY HASN`T BEEN
MOVING AS FAST AS EARLIER ANTICIPATED. CURRENT THINKING IS THAT
THE VERY SLOW EASTWARD PROGRESSION WILL CONTINUE TODAY...AND THEN
THE DIURNAL CLOUDS WILL DISSIPATE PRETTY RAPIDLY AFTER 00Z.

CARNEY

&&

.SHORT TERM...(THROUGH LATE THIS AFTERNOON)
ISSUED AT 315 AM CDT SUN APR 28 2013

AREAS OF DRIZZLE AND ISO-SCT RAIN SHOWERS SHOULD FINALLY END TODAY
AS A SLOW-MOVING LOW PRESSURE SYSTEM CONTINUES MOVING AWAY FROM THE
AREA. RAP BUFKIT PROFILES SHOW MIXING TO AROUND H9 THEREFORE HIGHS
IN THE LOW/MID 60S TO AROUND 70 LOOK REASONABLE CONSIDERING INITIAL
CLOUD COVER AND MOIST LOW LEVELS FM RECENT RAINFALL. TEMPERATURES
WILL BE WARMER IN CENTRAL MO THAN IN SWRN IL BECAUSE OF QUICKER
CLEARING IN THE WESTERN CWA.

KANOFSKY

.LONG TERM...(TONIGHT THROUGH SATURDAY)
ISSUED AT 315 AM CDT SUN APR 28 2013

(TONIGHT - WEDNESDAY)

UPPER LEVEL RIDGE WILL BUILD OVER ERN NOAM EARLY IN THE PERIOD AND
THEN PROCEED TO DOMINATE THRU THE MIDDLE OF THE WEEK...WITH A
TROF BUILDING OVER THE NWRN CONUS INITIALLY...BUT DEEPENING WITH
TIME AS IT SLOWLY TRANSLATES EWD INTO THE HI PLAINS BY WEDNESDAY.
THIS SHOULD GIVE US A PERIOD OF WARM AND MAINLY DRY WX.

THE WARMER MAV MOS IS A GOOD PLACE TO START FOR MONDAY AND TUESDAY
MAX TEMPS...BUT IN SEVERAL LOCALES...WENT A COUPLE DEGS HIGHER TO
SUPPORT H900-850 TEMPS ALOFT DEPICTED BY THE MODELS AND ANTICIPATED
SUNSHINE.  LOOK FOR UPR 70S-LO 80S ON MONDAY WITH MID 80S TUESDAY
WITH A MORE SW WIND EXPECTED.  AN OUTSIDE CHANCE AT UPR 80S WILL
PRESENT ITSELF FOR PARTS OF STL METRO TUESDAY.  LOSS OF W COMPONENT
TO SFC WND ON WEDNESDAY AND SOME UNCERTAINTY ON WHERE FRONT WILL
BE...HAVE 80-85F FCSTD FOR MOST SPOTS.

TWO SMALL WINDOWS OF OPPORTUNITY FOR RAIN THIS PERIOD.  THE FIRST IS
ON MONDAY AFTERNOON-NIGHT.  MODELS ALL SHOW PRETTY STOUT INSTABILITY
AND 0-6KM BULK SHEAR OF 30-35KTS IN PLACE AHEAD OF WHAT SHOULD BE A
CDFNT EDGING INTO THE NWRN FA BY LATE MONDAY AFTERNOON BEFORE IT
STALLS AND WASHES OUT MONDAY NIGHT.  HOWEVER...SOME OF THESE LARGE
INSTABILITY VALUES ARE PREDICATED ON WHAT LOOKS TO BE A TOO
AGGRESSIVE LO LEVEL MOISTURE RETURN...AND A DEPENDENCE IN PART ON
SFC DWPTS REACHING INTO THE MID-UPR 60S.  HOWEVER...LO LEVEL MASS
FIELDS DO NOT SUPPORT A LO LEVEL MOISTURE RETURN OF THAT MAGNITUDE
WITH WEAK FLOW AND A WEAK BLOCKING RIDGE NEAR THE GULF OF MEXICO
UNTIL MONDAY AFTERNOON AND THEN IT SHOULD BE TOO SMALL A TIME PERIOD
TO GET THE RICH MOISTURE THAT FAR N.  SFC DWPTS INSTEAD EDGING NEAR
60F LOOK MORE LIKELY BUT THIS WILL STILL YIELD CINH VALUES AT OR
ABOVE 20 J/KG WHICH WILL PROBABLY BE ALL IT WILL NEED TO BLOCK MOST
CONVECTION WITH A WEAKENING SFC FRONT.  BUFR SOUNDINGS BASED ON OUR
LOCAL WRF DEPICT THIS WELL.  SO...IF SOMETHING CAN POP...IT SHOULD
SUPPORT DAY SHIFT YESTERDAY/S ASSERTION WITH DECENT CHANCE OF IT
GOING TO SEVERE...BUT OCCURRENCE OF ANY CONVECTION LOOKS TO BE
PRETTY LIMITED.  AFTER SUNSET MONDAY EVENING...CINH RAPIDLY
INCREASES WITH THE SFC FRONT STARTING TO WASH OUT...AND SO WINDOW
FOR CONVECTION WILL RAPIDLY CLOSE.  MADE MINIMAL CHANGES TO PREVIOUS
FCST WHICH ALREADY HAD MINIMAL CHC POPS LIMITED TO THE NW FA.

STILL SOME MODEL DIFFS ON TIMING OF THE SFC CDFNT FOR MID-LATE
WEEK...WITH THE GFS CONTINUING TO BE THE FASTEST INTO OUR AREA BY
WEDNESDAY AFTERNOON WITH THE ECMWF SOME 12HRS LATER INTO EARLY
THURSDAY MORNING.  BACKED OFF SOME ON POPS FOR WEDNESDAY WITH THE
ECMWF CONTINUING TO LEAD THE GFS TO WHAT HOPEFULLY WILL BE THE
VERIFYING SOLN...WHICH HAS STEADILY BEEN FAVORING A SLOWER FROPA.

(THURSDAY - SATURDAY)

LOOKING INCREASINGLY LIKE A COOL AND WET PERIOD.

THE LARGE DISCREPANCY ON WHEN AND WHERE TO FORM THE CUTOFF LO HAS
BEEN OVERCOME FOR THE MOST PART WITH THE GFS FOLLOWING THE ECMWF/S
LEAD FOR A MORE RAPID FORMATION...AND FURTHER W AS A RESULT.  STILL
SOME SMALL DIFFS AND EXPECT TO SEE SOME WOBBLING THE NEXT DAY OR
TWO.  UNFORTUNATELY...WHEN DEALING WITH CUTOFF UPPER LOWS...EVERY
WOBBLE WILL MAKE A PRETTY BIG DIFFERENCE ON RAIN CHCS AND TEMPS.

THE LATEST ITERATION FROM THE 00Z MODELS HAS A GENERAL CONSENSUS ON
THE UPPER LO FORMING AROUND THE INTERSECTION OF KS-MO-OK-AR ON
FRIDAY AND THEN GRADUALLY PULLING NWD THRU SATURDAY.  THOSE SLIGHT
DIFFS WILL MAKE A BIG DEAL AT THE SFC...WHERE ECMWF SHOWS A MORE
AGGRESSIVE CDFNT PUSH ON THURSDAY WITH NOTHING OF THE SORT FROM THE
GFS AND SO A LARGE TEMP FCST DIFF AS A RESULT ARISES...ESPECIALLY
THURSDAY NIGHT AND FRIDAY.  A BROAD CONSENSUS APPROACH PREFERRED FOR
TEMPS AS A RESULT.

ONE THING THAT LOOKS INCREASINGLY LIKELY IS THE RAIN CHCS...
ESPECIALLY IF THE UPPER LO SETS UP IN THE RIGHT SPOT ALMOST LIKE
MODELS DEPICT NOW...COULD BE SOME HEAVY RAINFALL POTENTIAL AS IT
TAPS INTO GULF OF MEXICO MOISTURE.

TES

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1235 PM CDT SUN APR 28 2013
MVFR FLIGHT CONDITIONS WILL PREVAIL ACROSS MUCH THE AREA FOR THE
REST OF THE DAY...WITH PATCHES OF IFR CONTINUING OVER PARTS OF
SOUTHWEST ILLINOIS. CONDITIONS WILL GRADUALLY IMPROVE THROUGH THE
AFTERNOON...WITH MOST OF THE AREA CLEARING OUT BY MID-LATE
EVENING. EXPECT SOME MVFR FOG ALONG AND EAST OF THE MISSISSIPPI
RIVER LATE TONIGHT WITH AREAS OF IFR PROBABLY DEVELOPING OVER
PARTS OF SOUTHWEST/SOUTH CENTRAL ILLINOIS WHERE THE WIND WILL BE
LIGHTEST.

SPECIFICS FOR KSTL...
MVFR CIGS BELOW 2000FT WILL PREVAIL FOR A FEW MORE HOURS AT
LAMBERT BEFORE LIFTING ABOVE 2000FT. CURRENT THINKING IS THAT
CLOUDS SHOULD SCATTER OUT EARLY THIS EVENING. NOT SURE WHAT TO DO
ABOUT FOG POTENTIAL AT THIS TIME. THINK THERE WILL BE FOG IN THE
STL METRO AREA...MOST LIKELY 3-5SM VSBYS...BUT LAMBERT TENDS TO BE
LESS FOGGY THAN OTHER STATIONS. HAVE NOT INCLUDED FOG IN THE
CURRENT TAF...BUT WILL MENTION FOG POTENTIAL TO THE EVENING SHIFT.


CARNEY

&&

.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&

$$

WFO LSX







AREA FORECAST DISCUSSION...UPDATED AVIATION

NWS ST LOUIS MO

 636 AM CDT SUN APR 28 2013

.SHORT TERM...(THROUGH LATE THIS AFTERNOON)
ISSUED AT 315 AM CDT SUN APR 28 2013

AREAS OF DRIZZLE AND ISO-SCT RAIN SHOWERS SHOULD FINALLY END TODAY
AS A SLOW-MOVING LOW PRESSURE SYSTEM CONTINUES MOVING AWAY FROM THE
AREA. RAP BUFKIT PROFILES SHOW MIXING TO AROUND H9 THEREFORE HIGHS
IN THE LOW/MID 60S TO AROUND 70 LOOK REASONABLE CONSIDERING INITIAL
CLOUD COVER AND MOIST LOW LEVELS FM RECENT RAINFALL. TEMPERATURES
WILL BE WARMER IN CENTRAL MO THAN IN SWRN IL BECAUSE OF QUICKER
CLEARING IN THE WESTERN CWA.

KANOFSKY

.LONG TERM...(TONIGHT THROUGH SATURDAY)
ISSUED AT 315 AM CDT SUN APR 28 2013

(TONIGHT - WEDNESDAY)

UPPER LEVEL RIDGE WILL BUILD OVER ERN NOAM EARLY IN THE PERIOD AND
THEN PROCEED TO DOMINATE THRU THE MIDDLE OF THE WEEK...WITH A
TROF BUILDING OVER THE NWRN CONUS INITIALLY...BUT DEEPENING WITH
TIME AS IT SLOWLY TRANSLATES EWD INTO THE HI PLAINS BY WEDNESDAY.
THIS SHOULD GIVE US A PERIOD OF WARM AND MAINLY DRY WX.

THE WARMER MAV MOS IS A GOOD PLACE TO START FOR MONDAY AND TUESDAY
MAX TEMPS...BUT IN SEVERAL LOCALES...WENT A COUPLE DEGS HIGHER TO
SUPPORT H900-850 TEMPS ALOFT DEPICTED BY THE MODELS AND ANTICIPATED
SUNSHINE.  LOOK FOR UPR 70S-LO 80S ON MONDAY WITH MID 80S TUESDAY
WITH A MORE SW WIND EXPECTED.  AN OUTSIDE CHANCE AT UPR 80S WILL
PRESENT ITSELF FOR PARTS OF STL METRO TUESDAY.  LOSS OF W COMPONENT
TO SFC WND ON WEDNESDAY AND SOME UNCERTAINTY ON WHERE FRONT WILL
BE...HAVE 80-85F FCSTD FOR MOST SPOTS.

TWO SMALL WINDOWS OF OPPORTUNITY FOR RAIN THIS PERIOD.  THE FIRST IS
ON MONDAY AFTERNOON-NIGHT.  MODELS ALL SHOW PRETTY STOUT INSTABILITY
AND 0-6KM BULK SHEAR OF 30-35KTS IN PLACE AHEAD OF WHAT SHOULD BE A
CDFNT EDGING INTO THE NWRN FA BY LATE MONDAY AFTERNOON BEFORE IT
STALLS AND WASHES OUT MONDAY NIGHT.  HOWEVER...SOME OF THESE LARGE
INSTABILITY VALUES ARE PREDICATED ON WHAT LOOKS TO BE A TOO
AGGRESSIVE LO LEVEL MOISTURE RETURN...AND A DEPENDENCE IN PART ON
SFC DWPTS REACHING INTO THE MID-UPR 60S.  HOWEVER...LO LEVEL MASS
FIELDS DO NOT SUPPORT A LO LEVEL MOISTURE RETURN OF THAT MAGNITUDE
WITH WEAK FLOW AND A WEAK BLOCKING RIDGE NEAR THE GULF OF MEXICO
UNTIL MONDAY AFTERNOON AND THEN IT SHOULD BE TOO SMALL A TIME PERIOD
TO GET THE RICH MOISTURE THAT FAR N.  SFC DWPTS INSTEAD EDGING NEAR
60F LOOK MORE LIKELY BUT THIS WILL STILL YIELD CINH VALUES AT OR
ABOVE 20 J/KG WHICH WILL PROBABLY BE ALL IT WILL NEED TO BLOCK MOST
CONVECTION WITH A WEAKENING SFC FRONT.  BUFR SOUNDINGS BASED ON OUR
LOCAL WRF DEPICT THIS WELL.  SO...IF SOMETHING CAN POP...IT SHOULD
SUPPORT DAY SHIFT YESTERDAY/S ASSERTION WITH DECENT CHANCE OF IT
GOING TO SEVERE...BUT OCCURRENCE OF ANY CONVECTION LOOKS TO BE
PRETTY LIMITED.  AFTER SUNSET MONDAY EVENING...CINH RAPIDLY
INCREASES WITH THE SFC FRONT STARTING TO WASH OUT...AND SO WINDOW
FOR CONVECTION WILL RAPIDLY CLOSE.  MADE MINIMAL CHANGES TO PREVIOUS
FCST WHICH ALREADY HAD MINIMAL CHC POPS LIMITED TO THE NW FA.

STILL SOME MODEL DIFFS ON TIMING OF THE SFC CDFNT FOR MID-LATE
WEEK...WITH THE GFS CONTINUING TO BE THE FASTEST INTO OUR AREA BY
WEDNESDAY AFTERNOON WITH THE ECMWF SOME 12HRS LATER INTO EARLY
THURSDAY MORNING.  BACKED OFF SOME ON POPS FOR WEDNESDAY WITH THE
ECMWF CONTINUING TO LEAD THE GFS TO WHAT HOPEFULLY WILL BE THE
VERIFYING SOLN...WHICH HAS STEADILY BEEN FAVORING A SLOWER FROPA.

(THURSDAY - SATURDAY)

LOOKING INCREASINGLY LIKE A COOL AND WET PERIOD.

THE LARGE DISCREPANCY ON WHEN AND WHERE TO FORM THE CUTOFF LO HAS
BEEN OVERCOME FOR THE MOST PART WITH THE GFS FOLLOWING THE ECMWF/S
LEAD FOR A MORE RAPID FORMATION...AND FURTHER W AS A RESULT.  STILL
SOME SMALL DIFFS AND EXPECT TO SEE SOME WOBBLING THE NEXT DAY OR
TWO.  UNFORTUNATELY...WHEN DEALING WITH CUTOFF UPPER LOWS...EVERY
WOBBLE WILL MAKE A PRETTY BIG DIFFERENCE ON RAIN CHCS AND TEMPS.

THE LATEST ITERATION FROM THE 00Z MODELS HAS A GENERAL CONSENSUS ON
THE UPPER LO FORMING AROUND THE INTERSECTION OF KS-MO-OK-AR ON
FRIDAY AND THEN GRADUALLY PULLING NWD THRU SATURDAY.  THOSE SLIGHT
DIFFS WILL MAKE A BIG DEAL AT THE SFC...WHERE ECMWF SHOWS A MORE
AGGRESSIVE CDFNT PUSH ON THURSDAY WITH NOTHING OF THE SORT FROM THE
GFS AND SO A LARGE TEMP FCST DIFF AS A RESULT ARISES...ESPECIALLY
THURSDAY NIGHT AND FRIDAY.  A BROAD CONSENSUS APPROACH PREFERRED FOR
TEMPS AS A RESULT.

ONE THING THAT LOOKS INCREASINGLY LIKELY IS THE RAIN CHCS...
ESPECIALLY IF THE UPPER LO SETS UP IN THE RIGHT SPOT ALMOST LIKE
MODELS DEPICT NOW...COULD BE SOME HEAVY RAINFALL POTENTIAL AS IT
TAPS INTO GULF OF MEXICO MOISTURE.

TES

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 622 AM CDT SUN APR 28 2013

FLIGHT CONDITIONS WILL IMPROVE FROM WEST TO EAST TODAY AS A SLOW-
MOVING LOW PRESSURE SYSTEM MOVES AWAY FROM THE AREA. CIGS SHOULD
RISE TO MVFR AT ALL TAF SITES BY EARLY AFTN WITH CONTINUED
IMPROVEMENT THEREAFTER. INITIALLY NWLY TO WLY WINDS WILL GRADUALLY
BACK THROUGH THE TAF PD AND BECOME SLY OVERNIGHT. THERE MAY BE
SOME LIGHT FOG DVLPMT TONIGHT DUE TO THE MOIST LOW LEVELS AND
CLRG SKIES HOWEVER THE MOST FAVORABLE AREAS FOR DENSE FOG WILL BE
EAST OF THE TAF SITES.

SPECIFICS FOR KSTL...FLIGHT CONDITIONS WILL IMPROVE TODAY AS A
SLOW-MOVING LOW PRESSURE SYSTEM MOVES AWAY FROM THE AREA. CIGS
SHOULD RISE TO MVFR BY LATE MORNING WITH CONTINUED IMPROVEMENT
THEREAFTER. INITIALLY NWLY TO WLY WINDS WILL GRADUALLY BACK
THROUGH THE TAF PD AND BECOME SLY OVERNIGHT.

KANOFSKY

&&

.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&

$$

WFO LSX







AREA FORECAST DISCUSSION

NWS ST LOUIS MO

 315 AM CDT SUN APR 28 2013

.SHORT TERM...(THROUGH LATE THIS AFTERNOON)
ISSUED AT 315 AM CDT SUN APR 28 2013

AREAS OF DRIZZLE AND ISO-SCT RAIN SHOWERS SHOULD FINALLY END TODAY
AS A SLOW-MOVING LOW PRESSURE SYSTEM CONTINUES MOVING AWAY FROM THE
AREA. RAP BUFKIT PROFILES SHOW MIXING TO AROUND H9 THEREFORE HIGHS
IN THE LOW/MID 60S TO AROUND 70 LOOK REASONABLE CONSIDERING INITIAL
CLOUD COVER AND MOIST LOW LEVELS FM RECENT RAINFALL. TEMPERATURES
WILL BE WARMER IN CENTRAL MO THAN IN SWRN IL BECAUSE OF QUICKER
CLEARING IN THE WESTERN CWA.

KANOFSKY

.LONG TERM...(TONIGHT THROUGH SATURDAY)
ISSUED AT 315 AM CDT SUN APR 28 2013

(TONIGHT - WEDNESDAY)

UPPER LEVEL RIDGE WILL BUILD OVER ERN NOAM EARLY IN THE PERIOD AND
THEN PROCEED TO DOMINATE THRU THE MIDDLE OF THE WEEK...WITH A
TROF BUILDING OVER THE NWRN CONUS INITIALLY...BUT DEEPENING WITH
TIME AS IT SLOWLY TRANSLATES EWD INTO THE HI PLAINS BY WEDNESDAY.
THIS SHOULD GIVE US A PERIOD OF WARM AND MAINLY DRY WX.

THE WARMER MAV MOS IS A GOOD PLACE TO START FOR MONDAY AND TUESDAY
MAX TEMPS...BUT IN SEVERAL LOCALES...WENT A COUPLE DEGS HIGHER TO
SUPPORT H900-850 TEMPS ALOFT DEPICTED BY THE MODELS AND ANTICIPATED
SUNSHINE.  LOOK FOR UPR 70S-LO 80S ON MONDAY WITH MID 80S TUESDAY
WITH A MORE SW WIND EXPECTED.  AN OUTSIDE CHANCE AT UPR 80S WILL
PRESENT ITSELF FOR PARTS OF STL METRO TUESDAY.  LOSS OF W COMPONENT
TO SFC WND ON WEDNESDAY AND SOME UNCERTAINTY ON WHERE FRONT WILL
BE...HAVE 80-85F FCSTD FOR MOST SPOTS.

TWO SMALL WINDOWS OF OPPORTUNITY FOR RAIN THIS PERIOD.  THE FIRST IS
ON MONDAY AFTERNOON-NIGHT.  MODELS ALL SHOW PRETTY STOUT INSTABILITY
AND 0-6KM BULK SHEAR OF 30-35KTS IN PLACE AHEAD OF WHAT SHOULD BE A
CDFNT EDGING INTO THE NWRN FA BY LATE MONDAY AFTERNOON BEFORE IT
STALLS AND WASHES OUT MONDAY NIGHT.  HOWEVER...SOME OF THESE LARGE
INSTABILITY VALUES ARE PREDICATED ON WHAT LOOKS TO BE A TOO
AGGRESSIVE LO LEVEL MOISTURE RETURN...AND A DEPENDENCE IN PART ON
SFC DWPTS REACHING INTO THE MID-UPR 60S.  HOWEVER...LO LEVEL MASS
FIELDS DO NOT SUPPORT A LO LEVEL MOISTURE RETURN OF THAT MAGNITUDE
WITH WEAK FLOW AND A WEAK BLOCKING RIDGE NEAR THE GULF OF MEXICO
UNTIL MONDAY AFTERNOON AND THEN IT SHOULD BE TOO SMALL A TIME PERIOD
TO GET THE RICH MOISTURE THAT FAR N.  SFC DWPTS INSTEAD EDGING NEAR
60F LOOK MORE LIKELY BUT THIS WILL STILL YIELD CINH VALUES AT OR
ABOVE 20 J/KG WHICH WILL PROBABLY BE ALL IT WILL NEED TO BLOCK MOST
CONVECTION WITH A WEAKENING SFC FRONT.  BUFR SOUNDINGS BASED ON OUR
LOCAL WRF DEPICT THIS WELL.  SO...IF SOMETHING CAN POP...IT SHOULD
SUPPORT DAY SHIFT YESTERDAY/S ASSERTION WITH DECENT CHANCE OF IT
GOING TO SEVERE...BUT OCCURRENCE OF ANY CONVECTION LOOKS TO BE
PRETTY LIMITED.  AFTER SUNSET MONDAY EVENING...CINH RAPIDLY
INCREASES WITH THE SFC FRONT STARTING TO WASH OUT...AND SO WINDOW
FOR CONVECTION WILL RAPIDLY CLOSE.  MADE MINIMAL CHANGES TO PREVIOUS
FCST WHICH ALREADY HAD MINIMAL CHC POPS LIMITED TO THE NW FA.

STILL SOME MODEL DIFFS ON TIMING OF THE SFC CDFNT FOR MID-LATE
WEEK...WITH THE GFS CONTINUING TO BE THE FASTEST INTO OUR AREA BY
WEDNESDAY AFTERNOON WITH THE ECMWF SOME 12HRS LATER INTO EARLY
THURSDAY MORNING.  BACKED OFF SOME ON POPS FOR WEDNESDAY WITH THE
ECMWF CONTINUING TO LEAD THE GFS TO WHAT HOPEFULLY WILL BE THE
VERIFYING SOLN...WHICH HAS STEADILY BEEN FAVORING A SLOWER FROPA.

(THURSDAY - SATURDAY)

LOOKING INCREASINGLY LIKE A COOL AND WET PERIOD.

THE LARGE DISCREPANCY ON WHEN AND WHERE TO FORM THE CUTOFF LO HAS
BEEN OVERCOME FOR THE MOST PART WITH THE GFS FOLLOWING THE ECMWF/S
LEAD FOR A MORE RAPID FORMATION...AND FURTHER W AS A RESULT.  STILL
SOME SMALL DIFFS AND EXPECT TO SEE SOME WOBBLING THE NEXT DAY OR
TWO.  UNFORTUNATELY...WHEN DEALING WITH CUTOFF UPPER LOWS...EVERY
WOBBLE WILL MAKE A PRETTY BIG DIFFERENCE ON RAIN CHCS AND TEMPS.

THE LATEST ITERATION FROM THE 00Z MODELS HAS A GENERAL CONSENSUS ON
THE UPPER LO FORMING AROUND THE INTERSECTION OF KS-MO-OK-AR ON
FRIDAY AND THEN GRADUALLY PULLING NWD THRU SATURDAY.  THOSE SLIGHT
DIFFS WILL MAKE A BIG DEAL AT THE SFC...WHERE ECMWF SHOWS A MORE
AGGRESSIVE CDFNT PUSH ON THURSDAY WITH NOTHING OF THE SORT FROM THE
GFS AND SO A LARGE TEMP FCST DIFF AS A RESULT ARISES...ESPECIALLY
THURSDAY NIGHT AND FRIDAY.  A BROAD CONSENSUS APPROACH PREFERRED FOR
TEMPS AS A RESULT.

ONE THING THAT LOOKS INCREASINGLY LIKELY IS THE RAIN CHCS...
ESPECIALLY IF THE UPPER LO SETS UP IN THE RIGHT SPOT ALMOST LIKE
MODELS DEPICT NOW...COULD BE SOME HEAVY RAINFALL POTENTIAL AS IT
TAPS INTO GULF OF MEXICO MOISTURE.

TES

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1037 PM CDT SAT APR 27 2013

RAIN CONTINUES TO ROTATE THROUGH THE AREA BETWEEN UIN AND STL
UNDERNEATH AND AHEAD OF A MID LEVEL LOW JUST NW OF STL...AND
ALONG AND AHEAD OF THE INVERTED SFC TROUGH EXTENDING FROM A SFC
LOW OVER NWRN TN NW THROUGH ERN MO. MOST OF THIS RAIN SHOULD SHIFT
E OF THE TAF SITES BY 06Z SUN. ALTHOUGH MOST OF THE RAIN SHOULD
END LATE TGT THE CLOUD CEILING SHOULD REMAIN QUITE LOW...MAINLY
BELOW 1000 FT. SHOULD ALSO HAVE LIGHT FOG WITH PATCHY DRIZZLE DUE
TO PLENTY OF SFC/BOUNDARY LAYER MOISTURE. WEAK NLY SFC WIND WILL
BACK AROUND TO A NWLY DIRECTION LATE TGT AS THE SFC LOW MOVES E OF
THE TAF SITES. THE SFC WIND WILL CONTINUE TO BACK AROUND TO A
W-SWLY DIRECTION SUN AFTN AS WEAK SFC RIDGING BEHIND THE SFC LOW
BEGINS TO SHIFT E OF THE TAF SITES. THE FOG WILL DISSIPATE BY LATE
SUN MRNG WITH A GRADUAL RISE IN CLOUD CEILING HEIGHT INTO THE VFR
CATAGORY SUN AFTN AS WELL AS EVENTUAL SCATTERING OUT OF THE
CEILING. THE SFC WIND WILL BE MAINLY SLY SUN EVNG...ALBEIT QUITE
LIGHT WITH A CLEAR SKY.

SPECIFICS FOR KSTL...MOST OF THE RAIN SHOULD BE E OF STL LATE
TGT...ALTHOUGH THERE MAY STILL BE SOME PATCHY DRIZZLE. LIGHT FOG
CAN BE EXPECTED AS WELL WITH THE CEILING HEIGHT REMAINING BELOW
1000 FT. THE CLOUD CEILING WILL LIKELY RISE INTO THE MVFR CATAGORY
BY LATE SUN MRNG WITH THE FOG DISSIPATING. THE CEILING WILL
CONTINUE TO RISE INTO THE VFR CATAGORY BY LATE SUN AFTN...THEN
CLEAR OUT EARLY SUN EVNG. NLY SFC WIND WILL BACK AROUND TO A NWLY
DIRECTION LATE TGT...THEN TO A WLY DIRECTION SUN AFTN...AND TO A
LIGHT S-SWLY WIND SUN EVNG.

GKS

&&

.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&

$$

WFO LSX





AREA FORECAST DISCUSSION

NWS OMAHA/VALLEY NE

 903 PM CDT MON APR 29 2013

.UPDATE...
MAIN FORECAST CONCERN TONIGHT WILL BE CONVECTIVE POTENTIAL...AND
ADJUSTED CLOUDS...WINDS...AND DEWPOINTS TOO.

&&

.DISCUSSION...
THE WEAK H5 SHORTWAVE MOVING ACROSS THE AREA APPEARS TO HAVE
TOUCHED OFF SOME ISOLATED THUNDERSTORMS IN IOWA AND NOW WILL BE
WATCHING TO SEE HOW THUNDERSTORMS WILL DEVELOP AS THE LOW LEVEL
JET INCREASES. SEVERAL OF THE SHORT RANGE MODELS DEVELOPED
CONVECTION IN SOUTHEAST NEBRASKA AND SOUTHWEST IOWA...ALONG A WEAK
BOUNDARY AS DEEPER MOISTURE IS DRAWN NORTHWARD WITH THE INCREASING
LLJ. THE LATEST RAP AND 00Z NAM...ARE NOW MAINLY DRY THIS
EVENING. LEFT IN THE EVENING CHANCE FOR THUNDERSTORMS...BUT THINK
WITH VEERING H85 JET...ANYTHING THAT FORMS WILL QUICKLY SHIFT
NORTHEAST.

&&

.PREV DISCUSSION... /ISSUED 656 PM CDT MON APR 29 2013/

AVIATION...
00Z TAFS FOR KOMA...KLNK...KOFK.

WILL CONTINUE TO MONITOR SHRA/TSRA DEVELOPMENT EARLY THIS EVENING
AS THE LOW LEVEL JET INCREASES AND PULLS DEEPER MOISTURE
NORTHWARD...THIS...COMBINED WITH A SHORTWAVE PASSING THROUGH. STORMS
MAY HOLD OFF TO THE EAST AND CHANCES TOO LOCALIZED TO INCLUDE IN
THE EVENING TAFS. MAIN CHANCE WILL BE THRU 05Z BEFORE VEERING OF
WINDS PUSHES ANY PRECIPITATION OUT OF THE AREA. MENTIONED LOW
LEVEL WIND SHEAR IN THE KOMA AND KLNK TAFS FROM 06Z-12Z AS
SOUTHWEST WINDS AT FL020 INCREASE TO 55KTS. SOUTH TO SOUTHWEST
WINDS 8 TO 15KTS TONIGHT...BECOMING NORTH AT 10 TO 15KTS WITH
HIGHER GUSTS TUESDAY WITH THE FRONTAL PASSAGE. MORE SHOWERS AND
THUNDERSTORMS WILL BE POSSIBLE TUESDAY AFTERNOON. KOMA/KLNK MAY BE
NEAR THE NORTHERN FRINGE OF THE PRECIPITATION TUESDAY
AFTERNOON...SO WILL NOT MENTION LOWER CIGS AT THIS TIME.

PREV DISCUSSION... /ISSUED 253 PM CDT MON APR 29 2013/

SHORT TERM...TONIGHT THROUGH THURSDAY.

SURFACE COLD FRONT THAT HAD MOVED INTO SOUTHEAST NEBRASKA
OVERNIGHT HAD PRETTY MUCH WASHED OUT BY 19Z WITH SOUTHERLY WINDS
NOTED ACROSS THE AREA. STILL SOME CHANCE OF SHOWERS AND
THUNDERSTORMS FOR SOUTHEAST NEBRASKA AND SOUTHWEST IOWA THIS
EVENING AS A MID LEVEL WAVE OVER WESTERN NEBRASKA MOVES EAST WITH
BOTH THE GFS AND NAM SHOWING A POCKET OF ELEVATED INSTABILITY OVER
THAT AREA DURING THIS TIME BEFORE MOVING OFF TO THE EAST AFTER
06Z.

MODELS STILL SHOW SIMILAR TIMING FOR THE COLD FRONT JUST COMING
INTO THE NORTHERN PLAINS THIS AFTERNOON REACHING THE NORTHWEST
PORTION OF THE CWA BY 12Z TUESDAY...THEN SOUTHEAST CORNER OF
NEBRASKA BY LATE TUESDAY AFTERNOON. LITTLE CHANGE TO CURRENT
TREND OF INCREASING POPS STARTING TUESDAY AFTERNOON AND EXTENDING
INTO WEDNESDAY NIGHT AS THE SURFACE FRONT DROPS SLOWLY SOUTH AND
UPPER WAVE DIGS INTO THE PLAINS REGION. EASTERN PARTS OF THE AREA
STILL LOOK TO HAVE A CONTINUING CHANCE OF SHOWERS ON THURSDAY AS
CUTOFF LOW DEVELOPS IN VICINITY OF EASTERN KANSAS. TEMPERATURES
ALSO CONTINUE TO TREND BELOW NORMAL AS THE COLD AIR ASSOCIATED
WITH THE UPPER SYSTEM LINGERS OVER THE AREA. SOME SNOW POSSIBLE
WEDNESDAY NIGHT INTO EARLY THURSDAY FOR MUCH OF THE AREA HOWEVER
LITTLE ACCUMULATION EXPECTED AT THIS TIME.

LONG TERM...THURSDAY NIGHT THROUGH MONDAY.

PLACEMENT AND MOVEMENT OF THE CLOSED LOW STILL LOOKS TO BE THE
MAIN PROBLEM IN THE EXTENDED PERIOD. 12Z ECMWF APPEARS TO BE MORE
CONSISTENT WITH PREVIOUS MODEL RUNS WHILE GFS NOW TAKES THE
SYSTEM FURTHER SOUTH. SOME THREAT OF PRECIP INTO THE WEEKEND YET
WITH POTENTIAL FOR RAIN OR SNOW SHOWERS DEPENDING ON ACTUAL TRACK
OF THE SYSTEM.

FOBERT

&&

.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&

$$

ZAPOTOCNY




AREA FORECAST DISCUSSION

NWS HASTINGS NE

 252 PM CDT SUN APR 28 2013

.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 240 PM CDT SUN APR 28 2013

PRIMARY FORECAST CONCERN WILL BE SMALL CHANCES FOR THUNDERSTORMS
LATE THIS AFTERNOON AND EVENING IN THE NORTHEAST PART OF THE CWA
AND THEN ANOTHER SMALL CHANCE FOR SHOWERS IN THE NORTH PART OF THE
CWA OVERNIGHT.

UPPER AIR ANALYSIS AND CURRENT WATER VAPOR IMAGERY SHOW AN UPPER
LEVEL TROUGH MOVING ACROSS THE EASTERN THIRD OF THE COUNTRY WHILE
MORE OF A ZONAL FLOW IS NOTED FROM THE PACIFIC NW INTO THE CENTRAL
PLAINS. THERE ARE A COUPLE OF WEAK SHORT WAVES TO DEAL
WITH...ESPECIALLY ONE MOVING INTO MONTANA WHICH COULD PROVIDE SOME
FORCING ACROSS THE NORTHERN PART OF OUR CWA LATER TONIGHT.

AT THE SURFACE...A TROUGH OF LOW PRESSURE WAS JUST MOVING INTO THE
FAR WESTERN PART OF THE CWA BY 19Z. TEMPERATURES HAVE CLIMBED
STEADILY TODAY AND MOST LOCATIONS SHOULD HIT THE 80S BEFORE THE
AFTERNOON IS OUT. DEW POINTS RANGE FROM THE MID TO UPPER 40S EAST OF
THE SURFACE TROUGH...IN THE MID 30S ALONG THE TROUGH AXIS...AND THEN
DIPPING INTO THE MID 20S 50 TO 100 MILES BEHIND THE TROUGH.
REGARDING FIRE WEATHER CONCERNS...RELATIVE HUMIDITIES HAVE FALLEN
NEAR OR BELOW 20 PERCENT IN THE WEST...BUT WINDS SHOULD STAY BELOW
20 MPH IN THAT PART OF OUR CWA AS THE TROUGH AXIS LIES OVER THAT
AREA. BY THE TIME THE WINDS PICK UP AGAIN FROM THE NW...WE SHOULD BE
A FEW HOURS PAST MAX HEATING.

VARIOUS SHORT RANGE MODELS SHOWING SOME DECENT INSTABILITY AHEAD OF
THE SURFACE TROUGH WHICH COULD TRIGGER CONVECTION LATER THIS
AFTERNOON. BOTH THE HRRR AND THE 4KM WRF SHOWING TSTM DEVELOPMENT IN
THE NORTHEAST PART OF THE CWA FROM ROUGHLY 5 PM THROUGH 10 PM. WHILE
BETTER CHANCES SEEM TO BE JUST A LITTLE FURTHER NORTHEAST THAN OUR
CWA...WILL CONTINUE WITH AT LEAST A SLIGHT CHANCE IN OUR NORTHEAST
AS WE COULD CERTAINLY GET CLIPPED.

THE SHORTWAVE NOTED ABOVE SHOULD HAVE MORE OF AN IMPACT AFTER
MIDNIGHT AND CONTINUED THE CHANCE OF SHOWERS MAINLY IN THE
NORTHEASTERN HALF OF THE CWA. FORCING AND MOISTURE NOT OVERLY
IMPRESSIVE AND WILL KEEP POPS FAIRLY LOW. INSTABILITY ALSO DROPS OFF
QUITE A BIT SO WILL KEEP THUNDER MENTION OUT AFTER MIDNIGHT.

QUIET WEATHER EXPECTED ON MONDAY AS WE AWAIT THE APPROACH OF THE
NEXT SYSTEM UPSTREAM. WITH EASTERLY FLOW AT SURFACE...HIGH
TEMPERATURES SHOULD BE JUST A LITTLE BIT COOLER THAN WHAT WE ARE
SEEING TODAY...BUT ALL IN ALL STILL NOT BAD.

.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 240 PM CDT SUN APR 28 2013

THE WEATHER PATTERN WILL UNDERGO CHANGES DURING THE EXTENDED PERIODS
WITH A TREND TO COOLER SPRING CONDITIONS.

ON MONDAY NIGHT AN UPPER TROUGH DIGS SOUTH ACROSS THE
NORTHWEST/NORTH CENTRAL TIER STATES AND A SFC COLD FRONTAL BOUNDARY
PUSHES SOUTH FM THE DAKOTAS...AND IS EXPECTED TO STRETCH FM
ROUGHLY KOMA TO KPHG TO SOUTH OF KGLD BY 12Z TUESDAY. WITH FRONT
CROSSING MUCH OF OUR NEB CWA OVERNIGHT...CONSIDERED SOME LOW POPS
TOWARD TUESDAY MORNING BUT CHCS APPEAR HIT OR MISS AND WILL CARRY
SILENT POPS FOR NOW. IN GENERAL...MODELS HAVE CONTINUED TO TREND
FASTER WITH FROPA...WITH THE NAM REMAINING FASTER THAN GFS. THE
FARTHER SOUTH FRONTAL POSITION NEAR THE NEB/KS STATELINE OR IN
NORTHERN KANSAS PLACES CHCS FOR AFTN CONVECTION FARTHER SOUTH AS
WELL. DEPENDING ON TIMING/FRONTAL POSITION THERE STILL APPEARS TO
BE A WINDOW OF OPPORTUNITY...ALBEIT A SHRINKING WINDOW...FOR
POTENTIALLY A STRONG/SEVERE TSTMS IN THE LATE AFTN/EVE FOR OUR
SOUTHEAST ZONES. SOME PRESENCE OF ELEVATED INSTABILITY IS
MAINTAINED INTO THE FIRST PART OF THE NIGHT TUESDAY NIGHT WHICH
SHIFTS SOUTH BY WEDNESDAY MORNING. OVERALL PCPN CHCS INCREASE OVERNIGHT
TUESDAY NIGHT ACROSS OUR ENTIRE CWA IN INCREASING ISENTROPIC LIFT
AHEAD OF THE UPPER TROUGH MOVING ONTO THE CENTRAL PLAINS AND IN
PRESENCE OF STRONG MID LEVEL FRONTOGENESIS. MUCH COLDER AIR
ADVECTS SOUTH BEHIND THE FRONTAL BOUNDARY AND THE R/S LINE ACROSS
WESTERN NEBRASKA LOOKS TO EDGE CLOSE TO OUR NW CWA TOWARDS
WEDNESDAY MORNING.

WEDNESDAY IS SHAPING UP TO BE A COLD...WET...BREEZY/WINDY DAY UNDER
INFLUENCE OF UPPER TROUGH MOVING IN WITH THE BETTER CHCS FOR PCPN
EXPECTED IN THE FIRST PART OF THE DAY BEFORE DRIER AIR ADVECTS IN
FOLLOWING MID LEVEL TROUGH...BUT THIS WILL BE DEPENDENT UPON
SYSTEMN TIMING WITH GFS MORE PROGRESSIVE THAN ECMWF.

MODELS CONTINUE TO DEVIATE ON WHERE UPPER LOW WILL CLOSE OFF
THURS NIGHT/FRI DUE TO A BLOCKING RIDGE TO THE EAST. 24HRS AGO
THE 12Z MODELS CLOSED THE LOW ACROSS THE CENTRAL PLAINS...THEN
THE 00Z SUNDAY RUN OF MODELS CLOSED THE LOW IN EASTERN KS/SOUTHERN
MISSOURI...AND NOW THE 12Z GFS RUN CLOSES THE LOW EAST OF THE
MISSOURI RIVER IN IOWA WITH THE POTENTIAL FOR A CUTOFF SYSTEM TO
LIFT AND RETROGRADE TOWARD THE END OF THE WORKWEEK AND INTO THE
FIRST PART OF NEXT WEEKEND. THE 12Z ECMWF IS A LITTLE MORE SIMILAR
TO ITS PREVIOUS RUN INITIALLY WITH THE SYSTEM CLOSING OFF IN
EASTERN KS WITH THE CUTOFF UPPER LOW MEANDERING ACROSS MISSOURI
THRU THE WEEKEND. PCPN CHCS WILL BE DEPENDENT UPON THE UPPER LOW
PRESSURE SYSTEM POSITION AND IT IS JUST TOO EARLY TO PINPOINT THE
BEST CHCS/TIMING JUST YET GIVEN THE VARYING MODEL SOLUTIONS AND
DID NOT DEVIATE MUCH FROM THE EXTENDED INIT. UNDER THE INFLUENCE
OF THE UPPER LOW/TROUGH PATTERN...TEMPERATURES WILL REMAIN COOL WITH HIGHS
MAINLY 50S...AND LOWS IN THE 30S...ALTHOUGH READINGS COULD RECOVER
SOME IF LOW KICKS OUT TOWARD DAY 7. WITH LOWS IN THE 30S WILL NEED
TO CLOSELY MONITOR POTENTIAL FOR FROST/FREEZE AS SPRING HEADLINES
FOR THIS BEGIN MAY 1.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1219 PM CDT SUN APR 28 2013

EXPECT VFR CONDITIONS DURING THE FORECAST PERIOD. A SURFACE TROUGH
MOVING EAST ACROSS THE REGION WILL SWITCH WINDS FROM SOUTH TO
SOUTHWEST AND EVENTUALLY TO THE NORTH LATER THIS AFTERNOON AND
INTO TONIGHT. SPEEDS SHOULD RANGE IN THE 10-15 KT RANGE. JUST A VERY
SMALL CHANCE FOR ANY CONVECTION TO DEVELOP ALONG THIS TROUGH LATE
THIS AFTERNOON AND WILL NOT PUT IN THE TAF BUT WILL CONTINUE TO MONITOR.

&&

.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.

&&

$$

SHORT TERM...EWALD
LONG TERM...FAY
AVIATION...EWALD







AREA FORECAST DISCUSSION

NWS NORTH PLATTE NE

 107 PM CDT SUN APR 28 2013

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 337 AM CDT SUN APR 28 2013

SFC WINDS SHOULD INCREASE FROM THE WEST TOWARD MORNING AHEAD OF A
PACIFIC COLD FRONT FCST TO MOVE THROUGH DURING THE AFTN. THE RAP
SUPPORTS HIGHS IN THE MID 80S AHEAD OF THE FRONT ACROSS SWRN NEB AND
WINDS SHOULD INCREASE TO 15 TO 25 MPH AHEAD AND BEHIND THE FRONT.

FOR TONIGHT...A DISTURBANCE...CURRENTLY ACROSS THE NRN ROCKIES WILL
MOVE THROUGH NRN NEB. K INDICES SUPPORT TSTMS WEST OF HIGHWAY 83.
MOISTURE BELOW 700MB IS VERY LIMITED EAST OF 83 AND LAPSE RATES
NEARLY MOIST ADIABATIC.

.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 337 AM CDT SUN APR 28 2013

GUSTY SOUTHERLY WINDS AND CRITICALLY LOW RELATIVE HUMIDITY VALUES TO
BE EXPECTED ONCE AGAIN MONDAY AFTERNOON...WITH THE POTENTIAL OF
WIDESPREAD RED FLAG CONDITIONS.  FIRE HEADLINES MAY BE NECESSARY
ONCE AGAIN.  A SURFACE TROUGH OF LOW PRESSURE WILL DEEPEN ALONG THE
HIGH PLAINS ON MONDAY...ALLOWING FOR DOWNSLOPING SOUTHWESTERLY TO
WESTERLY WINDS AND HIGHS WELL INTO THE UPPER 70S...IF NOT LOW 80S.
WIND GUSTS WILL LIKELY EXCEED 25 MPH DURING PEAK HEATING AS THE
PRESSURE GRADIENT INCREASES AND STRONG TROPOSPHERIC MIXING
COMMENCES.  PREVIOUS FORECAST HAD HIGHS HANDLED WELL FOR
MONDAY...WITH ONLY MINOR UPWARD TWEAKS NEEDED ACROSS NORTHWESTERN
NEBRASKA...WHERE TEMPERATURES MAY SOAR IN ADVANCE OF A COLD FRONTAL
PASSAGE.  THE FRONT IS CURRENTLY PROGGED TO ARRIVE OVERNIGHT
MONDAY/EARLY TUESDAY...HOWEVER THERE IS LITTLE SUPPORT FOR
PRECIPITATION PRODUCTION INITIALLY.  PROXIMITY SOUNDINGS REVEAL VERY
LITTLE MOISTURE IN THE LOWER LEVELS...THUS WILL CONTINUE THE SILENT
14 POPS THROUGH THE OVERNIGHT.  TEMPERATURES HOWEVER WILL BE
NOTICEABLY COOLER ON TUESDAY...BUT THERE REMAINS DIFFERENCES BETWEEN
THE DETERMINISTIC SOLUTIONS IN THE AMOUNT OF COOLING...THE CONSENSUS
WOULD SUGGEST A 20-25F DECREASE IN HIGHS FROM MONDAY...WILL GO WITH
A RANGE OF HIGHS FROM THE MID 50S TO LOW 60S ACROSS THE CWA.  ALONG
WITH THE COOLER TEMPERATURES...PRECIPITATION CHANCES INCREASE
TUESDAY INTO WEDNESDAY AS A MIDLEVEL SHORTWAVE AND ASSOCIATED RRE OF
A 110 PLUS KT UPPER JET ADVANCES ON THE REGION.  THE HIGHEST QPF
WILL BE TIED TO THE MID-LEVEL FRONTOGENETIC FORCING WHICH SHOULD
BISECT THE CWA FROM SOUTHWEST TO NORTHEAST...WHICH MEANS CHANCES ARE
INCREASING FOR WELCOME WIDESPREAD QPF ACROSS THE HEART OF THE
SANDHILLS.  PTYPE MAY BECOME PROBLEMATIC EARLY ON WEDNESDAY...AS H85
TEMPERATURES ARE SHOWN TO FALL AS COLD AS -3C BY 12Z WEDNESDAY.
WILL INTRODUCE A RAIN/SNOW MIX ACROSS NORTHWEST NEBRASKA FROM
06Z-12Z...BUT NOT EXPECTING ANY ACCUMULATIONS AS GROUND TEMPERATURES
HAVE WARMED GREATLY.  GUIDANCE CAME IN COOLER ONCE AGAIN FOR
WEDNESDAY...AND GIVEN EXPECTED CLOUDY CONDITIONS WITH WEAK OR
NEUTRAL CAA...HIGHS IN THE LOWER 40S SHOULD BE THE NORM.  THE
REMAINDER OF THE EXTENDED FORECAST REMAINS INTERESTING AS A CLOSED
LOW DEVELOPS OVER CENTRAL KANSAS ON THURSDAY...AND THEREAFTER
MEANDERS AIMLESSLY THROUGH THE MISSOURI VALLEY/CORN BELT THROUGH THE
WEEKEND.  WITH BROAD CYCLONIC FLOW REMAINING ACROSS THE CENTRAL
CONUS...WILL MAINTAIN COOLER THAN NORMAL TEMPERATURES INTO NEXT
WEEKEND WITH CONTINUED SLIGHT CHANCES OF PRECIPITATION.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 100 PM CDT SUN APR 28 2013

ANOTHER HOT DAY WITH VFR CONDITIONS EXPECTED THIS AFTERNOON. A
WEAK COLD FRONT WILL CAUSE A SLIGHT WIND SHIFT FROM THE
WEST/NORTHWEST TO THE NORTH. WINDS SPEEDS WILL BE SIMILAR BOTH
AHEAD AND BEHIND THE FRONT...GUSTING TO 20 TO 25 KTS. A WEAK
DISTURBANCE WILL MOVE ACROSS THE AREA TONIGHT...AND SHOULD BE
ENOUGH TO SPARK SOME ISOLD/SCT SHOWERS AND THUNDERSTORMS...MAINLY
TO IMPACT NORTHERN NEB. FURTHER SOUTH AN INCREASE OF MID/HIGH
CLOUDS...HOWEVER DRIER LOWER LEVEL ATMOSPHERE SHOULD PREVENT ANY
DEVELOP. SYSTEM MOVES THROUGH QUICKLY WITH VFR AND DRY CONDITIONS
FOR MONDAY...WINDS DO BECOME SOUTHERLY DURING THE LATE MORNING
HOURS.

&&

.FIRE WEATHER...
ISSUED AT 337 AM CDT SUN APR 28 2013

RED FLAG CONDITIONS SHOULD DEVELOP AHEAD AND BEHIND THE COLD FRONT
FORECAST TO MOVE THROUGH SWRN NEB THIS AFTN. THE RAP AND HRRR ARE
LEADING THE WAY WITH DEW PTS IN THE 20S WHILE THE MOSGUIDE WIND
GUSTS ARE IN THE 20 TO 24 KT RANGE. THE DRIER MODEL DATA AND
STRONGER WIND GUSTS HAVE BEEN VERIFYING BETTER THAN THE WETTER
MODELS WHICH HAVE BEEN AS MUCH AS 10F TOO HIGH WITH DEW POINTS.

&&

.LBF WATCHES/WARNINGS/ADVISORIES...
RED FLAG WARNING UNTIL 8 PM CDT /7 PM MDT/ THIS EVENING FOR
NEZ204-206-209-210-219.

&&

$$

SHORT TERM...CDC
LONG TERM...JACOBS
AVIATION...MASEK
FIRE WEATHER...CDC







AREA FORECAST DISCUSSION

NWS HASTINGS NE

 1219 PM CDT SUN APR 28 2013

.UPDATE...
ISSUED AT 544 AM CDT SUN APR 28 2013

UPDATED THE FORECAST TO INCLUDE MENTION OF 1 MILE WITH THE FOG IN
THE FAR SOUTHEAST THIS MORNING AND TO INCLUDE SPRINKLES DOWN TO
THE STATE LINE LATE TONIGHT AS MORE MODELS ARE INDICATING SOME
POSSIBLE QPF...BUT AIR SHOULD BE SO DRY THAT SPRINKLE SHOULD
SUFFICE FARTHER TO THE SOUTH.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 515 AM CDT SUN APR 28 2013

BIGGEST CHALLENGE WILL BE DETERMINING EXTENT OF SOME POTENTIAL FOG
AND STRATUS IN THE SOUTHEASTERN CWA THIS MORNING...PLUS THE
POTENTIAL OF ISOLATED THUNDERSTORMS LATE THIS AFTERNOON/EVENING
NORTHEAST/EAST...AND ALSO A CHANCE OF RAIN LATE TONIGHT.
ALSO...DETERMINING THE HIGH TEMPERATURE TODAY COULD BE A BIT TRICKY.
ALSO...WE WILL BE APPROACHING ELEVATED FIRE DANGER FOR ROUGHLY OUR
NORTHWESTERN QUADRANT OF THE CWA.

THE HRRR WAS SPOT ON WITH FOG AND STRATUS YESTERDAY. WITH THE BEST
TRANSPORT OF MOISTURE SHIFTED SOUTHEAST...THE HRRR APPEARS TO BE ON
TRACK WITH DEVELOPING STRATUS AND FOG TO THE SOUTH. CURRENT
INTERPOLATIONS STILL CLIP US WITH STRATUS AND FOG IN OUR SOUTHEAST
EARLY THIS MORNING...MAINLY AFFECTING OUR 5 SOUTHEASTERN-MOST
COUNTIES. THIS IS EXTREMELY SHALLOW AND SHOULD NOT TAKE LONG TO BURN
OFF BY MID-MORNING.

THE DRY LINE STILL LOOKS LIKE IT WILL BE ON ITS WAY EAST...BUT WILL
STALL IN OUR CWA BEFORE A COLD FRONT MAKES ITS WAY SOUTH ACROSS THE
CWA...COMING FROM THE NORTHERN PLAINS. WITH LOWERING DEWPOINTS FOR
MUCH OF THE CWA...ALONG WITH THE POTENTIAL FOR COMPRESSIONAL WARMING
AND VERY WARM 850 MB TEMPERATURES...I HAVE INCREASED HIGH
TEMPERATURES SIGNIFICANTLY...WELL INTO THE MID 80S. JUDGING BY
RECENT MODEL PERFORMANCE...THIS IS THE DIRECTION TO TAKE.

ALSO...WE COULD GET AN ISOLATED THUNDERSTORM AS THE COLD FRONT MAKES
ITS WAY SOUTH...ESPECIALLY NORTHEAST/EAST WHERE INSTABILITY IS A
LITTLE HIGHER. BULK SHEAR WILL BE MARGINAL FOR SEVERE WEATHER...BUT
WE SHOULD HAVE JUST ENOUGH INSTABILITY TO THROW IN A MENTION OF
PERHAPS SOME HAIL UP TO THE SIZE OF NICKELS ALONG AND EAST OF
HIGHWAY 14.

A MID-LEVEL WAVE COULD GIVE US POST-FRONTAL SHOWER ACTIVITY IN THE
NORTH. THERE DOES NOT APPEAR TO BE ENOUGH MID-LEVEL INSTABILITY TO
SUPPORT THUNDER. ENSEMBLES SUGGEST RAIN POTENTIALLY FARTHER
SOUTH...BUT THIS DOES NOT APPEAR TO BE A POPULAR SOLUTION ON HIGH
RESOLUTION SHORT RANGE MODELS...SO I WILL CONTINUE TO FOCUS CHANCES
IN OUR NORTHERN CWA. THE 06Z RUN DOES INDICATE POSSIBLE RAIN AS FAR
SOUTH AS THE STATE BORDER...POSSIBLY HELPED BY A WEAK AREA OF LEFT
INDUCED BY THE RIGHT REAR QUADRANT OF AN EXTREMELY MODELS JET
STREAK.

.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 515 AM CDT SUN APR 28 2013

ALTHOUGH UNCERTAINTY REMAINS HIGH IN THE DETAILS...THE GENERAL
THEME OF THIS 6-DAY PERIOD HAS CHANGED LITTLE OVER THE PAST 24
HOURS...WITH AT LEAST ONE MORE DAY OF ABOVE NORMAL WARMTH ON
MONDAY FOLLOWED BY THE PASSAGE OF A STRONG COLD FRONT
TUESDAY/TUESDAY NIGHT...WITH WELL BELOW NORMAL TEMPS THEN
PREVAILING THROUGH THE REMAINDER OF THE WEEK...ALTHOUGH THE JURY
IS STILL OUT ON JUST HOW COLD. PRECIP-WISE...ALL OR PART OF THE
CWA NOW HAS POPS MENTIONED FOR 9 CONSECUTIVE FORECAST PERIODS FROM
TUESDAY AFTERNOON THROUGH SATURDAY. THIS IS NOT AN IDEAL SITUATION
FOR PUBLIC FORECAST PRODUCTS AS IT OFTEN CREATES THE IMPRESSION
THAT IT WILL BE WETTER THAN IT ACTUALLY ENDS UP BEING...BUT GIVEN
MODEL VARIABILITY ITS JUST THE WAY IT IS FOR NOW. IN ALL REALITY
THOUGH...SOME OF THESE POPS MAY EVENTUALLY BE REDUCED/CUT IN
LATER FORECASTS...AS MODELS CONTINUE TO VARY CONSIDERABLY FROM
RUN-TO-RUN WITH THE PLACEMENT/LIKELIHOOD OF PRECIP POTENTIAL
BEYOND WEDNESDAY NIGHT. AT THIS POINT...BY FAR THE BEST CHANCES
FOR WIDESPREAD RAIN...AND POSSIBLY EVEN SOME SNOW MIXED
IN...OCCURS BETWEEN TUESDAY NIGHT AND WEDNESDAY NIGHT...WITH
UNCERTAINTY RAMPING UP THEREAFTER. THERE ALSO REMAINS A RISK FOR
STRONG/SEVERE STORMS TUESDAY AFTERNOON BUT LIKELY MORE SO TUESDAY
EVENING. ON TO THE DETAILS...

MONDAY/MONDAY NIGHT...CONFIDENCE REMAINS REASONABLY HIGH IN A DRY
24 HOURS. VARIOUS 00Z MODELS SUCH AS THE NAM/GFS/ECMWF AGREE THAT
THE LARGE SCALE PICTURE ALOFT FEATURES QUASI-ZONAL FLOW...AS ONE
LOW AMPLITUDE SHORTWAVE TROUGH DEPARTS EAST OF THE CWA DURING THE
DAY...WHILE UPSTREAM AN UPPER JET STREAK STARTS CARVING OUT
LARGER...BROADER TROUGH OVER THE NORTHERN ROCKIES/NORTHERN PLAINS.
RIGHT AWAY IN THE MORNING...IT COULD BE A CLOSE CALL WHETHER OR
NOT A BRIEF PERIOD OF LINGERING SPRINKLES/LIGHT SHOWERS FROM THE
SUNDAY NIGHT PERIOD COULD STILL BE SKIRTING EASTERN ZONES...BUT
VARIOUS MODELS INCLUDING REFLECTIVITY PROG FROM 4 KM WRF-NMM SHOVE
THIS ACTIVITY EAST BY 12Z SO WILL KEEP THE OFFICIAL MORNING PERIOD
PRECIP-FREE. LATER IN THE DAY...MODELS SUCH AS THE NAM BUILD A
HEALTHY AREA OF 2000+ J/KG SURFACE-BASED CAPE IN SOUTHEAST
COUNTIES...BUT NOT THINKING MUCH OF A THUNDERSTORM THREAT DUE TO
LIMITED FORCING AND PLENTY OF CAPPING EVIDENT IN FORECAST
SOUNDINGS. FURTHERMORE...THE MAGNITUDE OF MODELED INSTABILITY IS
LIKELY A BIT OVERDONE DUE TO OVERDONE SURFACE DEW POINT VALUES.
ASSUMING NO CONVECTION FIRES...IT SHOULD BE A QUIET AND MILD DAY
AS SURFACE BREEZES GENERALLY 10-15 MPH TRANSITION FROM EASTERLY TO
SOUTHERLY. GIVEN SLIGHTLY COOLER 850MB TEMPS AND LESS FAVORABLE
MIXING THAN TODAY...ANTICIPATE A SLIGHTLY COOLER MONDAY...AND MADE
LITTLE CHANGE TO HIGHS RANGING FROM MID 70S FAR NORTH TO LOW 80S
SOUTHWEST. LATE MONDAY NIGHT...THERE IS DECENT MODEL CONSENSUS
THAT THE LEADING EDGES OF THE COLD FRONT RACES SOUTHEAST INTO THE
NORTHWESTERN CWA BEFORE SUNRISE...ALTHOUGH THE NAM/GFS SEEM TO BE
FASTER WITH THIS FRONTAL INVASION THAN THE ECMWF. THE LATEST 06Z
NAM IS NOW SUGGESTING A NARROW LINE OF SHOWS/STORMS COULD BRUSH
FAR NORTHERN ZONES LATE MONDAY NIGHT JUST BEHIND THIS FRONT...BUT
WITH LIMITED SUPPORT FROM OTHER SOLUTIONS WILL OMIT ANY PRECIP
MENTION FOR NOW ALTHOUGH IT BEARS WATCHING. MADE LITTLE CHANGE TO
LOW TEMPS WITH LOW-MID 50S MOST AREAS EXCEPT UPPER 40S FAR
NORTHWEST.

TUESDAY/TUESDAY NIGHT...THINGS BECOME MORE ACTIVE ITS JUST A
MATTER OF HOW MUCH SO. ALOFT...THE NORTHERN ROCKIES/NORTHERN
PLAINS TROUGH AMPLIFIES IN A POSITIVELY TILTED FASHION...WHILE IN
THE LOW LEVELS THE FAIRLY STRONG COLD FRONT CONTINUES TO SWEEP
SOUTHWARD ACROSS THE CWA...AND HAVE INCREASED NORTH-NORTHEAST
SUSTAINED WIND SPEEDS TO AROUND 20 MPH IN ITS WAKE. FOR SOME
REASON...THE 00Z ECMWF IS STARTING TO LOOK LIKE MORE OF AN OUTLIER
WITH ITS SLOWER COLD FRONTAL PASSAGE...ALTHOUGH THE NAM MAY BE A
BIT TOO AGGRESSIVE. THIS UNCERTAINTY IN THE MAGNITUDE OF DAYTIME COLD
AIR ADVECTION RESULTS IN QUITE A BIT OF UNCERTAINTY IN HIGH
TEMPS...AND COULD EASILY SEE CURRENT FORECAST BEING 5-10 DEGREES
OFF FROM CURRENTLY ADVERTISED VALUES...WHICH ARE A MULTI-MODEL
BLEND. LEANING TOWARD THE FASTER COLD AIR INVASION...NUDGED DOWN
HIGHS ROUGHLY 3-4 DEGREES FROM PREVIOUS...AIMING FOR A DECENT
GRADIENT FROM NEAR 60 FAR NORTH TO UPPER 70S FAR SOUTHEAST. AS FOR
CONVECTIVE POTENTIAL...HELD OFF ANY MENTION OF DAYTIME STORMS
UNTIL POST-21Z...AND KEPT THE EXACT SAME AREA FROM PREVIOUS
FORECAST MAINLY SOUTH OF A YORK-ALMA LINE IN CLOSEST PROXIMITY TO
THE SURFACE FRONT. HOWEVER...IF THE FASTER FRONTAL SOLUTIONS SUCH
AS THE NAM VERIFY THEN THE PRIMARY LOW LEVEL INSTABILITY AXIS AND
RESULTANT RISK FOR POTENTIALLY NEAR-SURFACE BASED STORMS WOULD
ACTUALLY FOCUS SOUTHEAST OF THE CWA. THIS COULD BE A CLOSE CALL.
OF GREATER CONFIDENCE AT THIS POINT IS AN INCREASE IN COVERAGE OF
EVENING/OVERNIGHT PRECIPITATION WELL-BEHIND THE SURFACE
FRONT...AS LARGE SCALE MID LEVEL CONVERGENCE MOVES IN FROM THE
NORTHWEST. EVEN IF THE CWA IS SPARED SURFACE-BASED STORMS...IT
STILL LOOKS LIKE A FAIRLY AGGRESSIVE DEVELOPMENT OF AT LEAST
SLIGHTLY ELEVATED STORMS WILL FLARE UP NEAR OR SHORTLY AFTER
SUNSET IN RESPONSE TO INCREASING MOISTURE TRANSPORT/WIND
CONVERGENCE INTO THE MID-LEVEL FRONTAL ZONE EVIDENT AT 700MB.
WHILE HAIL WOULD LIKELY BE THE MAIN THREAT WITH THESE STORMS...THE
MAGNITUDE OF THE SEVERE RISK WILL ULTIMATELY DEPEND ON THE AMOUNT
OF ELEVATED INSTABILITY...WITH THE LATEST NAM ONLY ADVERTISING
LESS THAN 500 J/KG IN THE 850-700MB LAYER...BUT THE GFS STILL
CLOSER TO 1000 J/KG. DEEP LAYER SHEAR WILL BE PLENTY STRONG TO
SUPPORT AT LEAST MARGINAL SEVERE...AVERAGING AROUND 50KT.
CERTAINLY THE MAIN SEVERE THREAT AREA SHOULD FOCUS ACROSS ROUGHLY
THE SOUTHEAST 1/3 OF THE CWA...AND WILL BE MAKING LITTLE CHANGE
TO HAZARDOUS WEATHER OUTLOOK WORDING. EVEN NORTH OF THE MAIN
THUNDERSTORM AREA...WIDESPREAD RAIN SHOWERS SHOULD BREAK OUT
DURING THE NIGHT...AND POPS WERE RAISED TO 70 PERCENT ACROSS
NEARLY THE ENTIRE CWA. ALTHOUGH THE NAM/GFS THERMAL PROFILES
SUGGEST THAT SOME WET SNOW COULD MIX IN WITH RAIN MAINLY IN FAR
NORTHWEST ZONES LATE IN THE NIGHT...WILL KEEP PRECIP TYPE AS ALL
RAIN FOR NOW...DESPITE LOW TEMPS AIMED FROM MID 30S NORTHWEST TO
MID 40S SOUTHEAST.

WEDNESDAY/WEDNESDAY NIGHT...BY THIS TIME THE CWA IS FIRMLY IN THE
GRIPS OF THE COLDER REGIME. THE 00Z ECMWF/GFS RUNS ARE IN BETTER
AGREEMENT THAN 24 HOURS AGO ON THE SYNOPTIC SCENE...AS THEY BOTH
SLOWLY SHIFT THE INCREASINGLY-AMPLIFIED BUT STILL POSITIVELY
TILTED MID-UPPER TROUGH FROM THE NORTHERN PLAINS/CENTRAL ROCKIES
INTO THE CENTRAL PLAINS...WHILE AT THE SURFACE BREEZY NORTH WINDS
PERSIST. THE DOWNWARD NUDGING TO DAYTIME HIGHS CONTINUES...AND NOW
HAVE ALL BUT THE FAR SOUTHEAST CWA ONLY TOPPING OUT SOMEWHERE IN
THE 40S...WITH FURTHER DOWNWARD NUDGES STILL VERY MUCH POSSIBLE
GIVEN THAT PRECIP IS STILL EXPECTED TO BE FAIRLY WIDESPREAD DURING
THE DAY AS THE SOUTHWEST-NORTHEAST ORIENTED MID LEVEL
FRONTOGENETIC ZONE CENTERS OVERHEAD. AT LEAST FOR ONE MORE
FORECAST CYCLE...HAVE LEFT DAYTIME PRECIP TYPE AS RAIN-
ONLY...ALTHOUGH ITS BECOMING INCREASINGLY LIKELY THAT AT LEAST A
MIX WITH SNOW MAY SOON NEED INSERTED ESPECIALLY IN NORTHWEST
AREAS...ESPECIALLY IF HIGH TEMPS CONTINUE A DOWNWARD TREND. BY
THIS TIME INSTABILITY SHOULD BE MINIMAL EVEN IN SOUTHEAST COUNTIES
AND WILL LEAVE OUT THUNDER. POPS WERE UPPED TO 60 PERCENT
LIKELIES IN MOST AREAS...AS THIS IS SHAPING UP TO BE A RATHER WET
AND VERY RAW FIRST DAY OF MAY. WEDNESDAY NIGHT...KEPT AT LEAST
30-50 POPS GOING ALL AREAS FOR A RAIN/SNOW MIX WITH A LIGHT SNOW
ACCUMULATION NOT OUT OF THE QUESTION...ALTHOUGH BOTH THE ECMWF/GFS
ARE IN DECENT AGREEMENT PUSHING PRECIP OUT FROM NORTHWEST-
SOUTHEAST AS THE NIGHT WEARS ON. KEPT LOW TEMPS BARELY ABOVE
FREEZING ACROSS MOST OF THE CWA WEDNESDAY NIGHT...BUT ANY FROST
THREAT WOULD SEEM VERY MINIMAL GIVEN ONGOING PRECIP AND CONTINUED
MODEST NORTH BREEZES.

TURNING TO THE THURSDAY THROUGH SATURDAY TIME FRAME IN LESS
DETAILED FASHION...THE ONE BIT OF GOOD NEWS IS THAT THE ECWMF/GFS
SOLUTIONS ARE NOW IN INCREDIBLY GOOD AGREEMENT...AT LEAST FOR NOW...ON
THE EVOLUTION OF THE TIGHTLY WOUND CLOSED MID LEVEL LOW THAT IS
FORECAST TO DEVELOP ACROSS THE CENTRAL CONUS AS THE PARENT LARGE
SCALE TROUGH AXIS RUNS INTO A SOLID WALL IN THE FORM OF A STOUT
OMEGA BLOCK RIDGE OVER THE EASTERN CONUS. THE BEGINNING STAGES OF
THIS CLOSING OFF PROCESS TAKES PLACE THURS/THURS NIGHT...GENERALLY
CENTERED SOMEWHERE BETWEEN NORTHERN OK AND EASTERN KS. THIS IS
FARTHER EAST IN THE ECMWF FROM PREVIOUS RUNS...WITH THIS MODEL NOW
ACTUALLY KEEPING MOST OF THE CWA DRY FROM THURS AFTERNOON THROUGH
FRIDAY EVENING. HOWEVER...GIVEN PLENTY OF UNCERTAINTY IN THIS
LATEST SOLUTION WILL KEEP LOW POPS FOR EITHER CHILLY RAIN OR A
RAIN/SNOW MIX GOING ACROSS PART OR ALL OF THE CWA THIS ENTIRE TIME
FOR NOW. BY FRIDAY NIGHT INTO SATURDAY...BOTH OF THESE MODELS LIFT
THE CLOSED LOW BACK NORTH FROM MO TOWARD IA...WITH EVEN THE ECMWF
WRAPPING PRECIP CHANCES WESTWARD BACK INTO AT LEAST THE EASTERN
CWA BY THIS TIME. DAILY/NIGHTLY TEMPERATURES WILL DEPEND SO MUCH
ON WHETHER OR NOT WIDESPREAD CLOUDS AND/OR PRECIP ARE
PRESENT...BUT AT LEAST FOR NOW CONTINUED THE DOWNWARD TREND FOR
HIGH TEMPS THURS-SAT...WITH MAINLY UPPER 40S NOW THURS AND LOW 50S
FRI-SAT. OVERNIGHT LOWS BOTH FRI AND SAT MORNING ARE FORECAST
RIGHT AROUND OR JUST BELOW THE 32 DEGREE FREEZING MARK...BUT
HOLDING ABOVE THE 28 DEGREE HARD FREEZE THRESHOLD. AT THE VERY
LEAST...MAY EVENTUALLY HAVE TO INSERT A FROST MENTION FOR FRIDAY
MORNING...BUT CONFIDENCE IS TOO LOW AT THIS TIME RANGE...AND THERE
ARE ALREADY PLENTY MORE IMMEDIATE ISSUES TO DEAL WITH IN THE
SHORTER TERM...SO WILL NOT EXPLICITLY INTRODUCE FROST/FREEZE
CONCERNS IN THE FORECAST PRODUCTS JUST YET. HOWEVER...ITS CERTAINLY
NOT OUT OF THE QUESTION THAT AT LEAST ONE NIGHT MID-LATE NEXT
WEEK COULD REQUIRE A FROST/FREEZE HEADLINE.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1219 PM CDT SUN APR 28 2013

EXPECT VFR CONDITIONS DURING THE FORECAST PERIOD. A SURFACE TROUGH
MOVING EAST ACROSS THE REGION WILL SWITCH WINDS FROM SOUTH TO
SOUTHWEST AND EVENTUALLY TO THE NORTH LATER THIS AFTERNOON AND
INTO TONIGHT. SPEEDS SHOULD RANGE IN THE 10-15 KT RANGE. JUST A VERY
SMALL CHANCE FOR ANY CONVECTION TO DEVELOP ALONG THIS TROUGH LATE
THIS AFTERNOON AND WILL NOT PUT IN THE TAF BUT WILL CONTINUE TO MONITOR.

&&

.FIRE WEATHER...
ISSUED AT 515 AM CDT SUN APR 28 2013

FOR TODAY...THE DRY LINE STILL LOOKS LIKE IT WILL BE ON ITS WAY
EAST...BUT WILL STALL IN OUR CWA BEFORE A COLD FRONT MAKES ITS WAY
SOUTH ACROSS THE CWA...COMING FROM THE NORTHERN PLAINS. WITH
LOWERING DEWPOINTS FOR MUCH OF THE CWA...ALONG WITH THE POTENTIAL
FOR COMPRESSIONAL WARMING AND VERY WARM 850 MB TEMPERATURES...I
HAVE INCREASED HIGH TEMPERATURES SIGNIFICANTLY...WELL INTO THE MID
80S. RELATIVE HUMIDITY SHOULD BE SOLIDLY DRY FOR ITS PART TOWARD
CRITICAL FIRE WEATHER...BUT THE WINDS WILL BE LACKING A BIT...WITH
THE MOST POTENTIAL FOR FIRE ISSUES COMING FROM THE GUSTS AS THE
COLD FRONT MAKES ITS WAY TOWARD THE NORTHWESTERN CWA BY MID-LATE
AFTERNOON.

&&

.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&

$$

UPDATE...HEINLEIN
SHORT TERM...HEINLEIN
LONG TERM...PFANNKUCH
AVIATION...EWALD
FIRE WEATHER...HEINLEIN







AREA FORECAST DISCUSSION...UPDATED

NWS NORTH PLATTE NE

 623 AM CDT SUN APR 28 2013

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 337 AM CDT SUN APR 28 2013

SFC WINDS SHOULD INCREASE FROM THE WEST TOWARD MORNING AHEAD OF A
PACIFIC COLD FRONT FCST TO MOVE THROUGH DURING THE AFTN. THE RAP
SUPPORTS HIGHS IN THE MID 80S AHEAD OF THE FRONT ACROSS SWRN NEB AND
WINDS SHOULD INCREASE TO 15 TO 25 MPH AHEAD AND BEHIND THE FRONT.

FOR TONIGHT...A DISTURBANCE...CURRENTLY ACROSS THE NRN ROCKIES WILL
MOVE THROUGH NRN NEB. K INDICES SUPPORT TSTMS WEST OF HIGHWAY 83.
MOISTURE BELOW 700MB IS VERY LIMITED EAST OF 83 AND LAPSE RATES
NEARLY MOIST ADIABATIC.

.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 337 AM CDT SUN APR 28 2013

GUSTY SOUTHERLY WINDS AND CRITICALLY LOW RELATIVE HUMIDITY VALUES TO
BE EXPECTED ONCE AGAIN MONDAY AFTERNOON...WITH THE POTENTIAL OF
WIDESPREAD RED FLAG CONDITIONS.  FIRE HEADLINES MAY BE NECESSARY
ONCE AGAIN.  A SURFACE TROUGH OF LOW PRESSURE WILL DEEPEN ALONG THE
HIGH PLAINS ON MONDAY...ALLOWING FOR DOWNSLOPING SOUTHWESTERLY TO
WESTERLY WINDS AND HIGHS WELL INTO THE UPPER 70S...IF NOT LOW 80S.
WIND GUSTS WILL LIKELY EXCEED 25 MPH DURING PEAK HEATING AS THE
PRESSURE GRADIENT INCREASES AND STRONG TROPOSPHERIC MIXING
COMMENCES.  PREVIOUS FORECAST HAD HIGHS HANDLED WELL FOR
MONDAY...WITH ONLY MINOR UPWARD TWEAKS NEEDED ACROSS NORTHWESTERN
NEBRASKA...WHERE TEMPERATURES MAY SOAR IN ADVANCE OF A COLD FRONTAL
PASSAGE.  THE FRONT IS CURRENTLY PROGGED TO ARRIVE OVERNIGHT
MONDAY/EARLY TUESDAY...HOWEVER THERE IS LITTLE SUPPORT FOR
PRECIPITATION PRODUCTION INITIALLY.  PROXIMITY SOUNDINGS REVEAL VERY
LITTLE MOISTURE IN THE LOWER LEVELS...THUS WILL CONTINUE THE SILENT
14 POPS THROUGH THE OVERNIGHT.  TEMPERATURES HOWEVER WILL BE
NOTICEABLY COOLER ON TUESDAY...BUT THERE REMAINS DIFFERENCES BETWEEN
THE DETERMINISTIC SOLUTIONS IN THE AMOUNT OF COOLING...THE CONSENSUS
WOULD SUGGEST A 20-25F DECREASE IN HIGHS FROM MONDAY...WILL GO WITH
A RANGE OF HIGHS FROM THE MID 50S TO LOW 60S ACROSS THE CWA.  ALONG
WITH THE COOLER TEMPERATURES...PRECIPITATION CHANCES INCREASE
TUESDAY INTO WEDNESDAY AS A MIDLEVEL SHORTWAVE AND ASSOCIATED RRE OF
A 110 PLUS KT UPPER JET ADVANCES ON THE REGION.  THE HIGHEST QPF
WILL BE TIED TO THE MID-LEVEL FRONTOGENETIC FORCING WHICH SHOULD
BISECT THE CWA FROM SOUTHWEST TO NORTHEAST...WHICH MEANS CHANCES ARE
INCREASING FOR WELCOME WIDESPREAD QPF ACROSS THE HEART OF THE
SANDHILLS.  PTYPE MAY BECOME PROBLEMATIC EARLY ON WEDNESDAY...AS H85
TEMPERATURES ARE SHOWN TO FALL AS COLD AS -3C BY 12Z WEDNESDAY.
WILL INTRODUCE A RAIN/SNOW MIX ACROSS NORTHWEST NEBRASKA FROM
06Z-12Z...BUT NOT EXPECTING ANY ACCUMULATIONS AS GROUND TEMPERATURES
HAVE WARMED GREATLY.  GUIDANCE CAME IN COOLER ONCE AGAIN FOR
WEDNESDAY...AND GIVEN EXPECTED CLOUDY CONDITIONS WITH WEAK OR
NEUTRAL CAA...HIGHS IN THE LOWER 40S SHOULD BE THE NORM.  THE
REMAINDER OF THE EXTENDED FORECAST REMAINS INTERESTING AS A CLOSED
LOW DEVELOPS OVER CENTRAL KANSAS ON THURSDAY...AND THEREAFTER
MEANDERS AIMLESSLY THROUGH THE MISSOURI VALLEY/CORN BELT THROUGH THE
WEEKEND.  WITH BROAD CYCLONIC FLOW REMAINING ACROSS THE CENTRAL
CONUS...WILL MAINTAIN COOLER THAN NORMAL TEMPERATURES INTO NEXT
WEEKEND WITH CONTINUED SLIGHT CHANCES OF PRECIPITATION.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 621 AM CDT SUN APR 28 2013

VFR IS EXPECTED THROUGH 03Z THIS EVENING. THEREAFTER AND AREA OF
SHOWERS AND ISOLATED THUNDERSTORMS IS EXPECTED TO MOVE RAPIDLY
EAST ACROSS NRN NEB...GENERALLY ALONG HIGHWAY 20. CIGS SHOULD
REMAIN VFR.

&&

.FIRE WEATHER...
ISSUED AT 337 AM CDT SUN APR 28 2013

RED FLAG CONDITIONS SHOULD DEVELOP AHEAD AND BEHIND THE COLD FRONT
FORECAST TO MOVE THROUGH SWRN NEB THIS AFTN. THE RAP AND HRRR ARE
LEADING THE WAY WITH DEW PTS IN THE 20S WHILE THE MOSGUIDE WIND
GUSTS ARE IN THE 20 TO 24 KT RANGE. THE DRIER MODEL DATA AND
STRONGER WIND GUSTS HAVE BEEN VERIFYING BETTER THAN THE WETTER
MODELS WHICH HAVE BEEN AS MUCH AS 10F TOO HIGH WITH DEW POINTS.

&&

.LBF WATCHES/WARNINGS/ADVISORIES...
RED FLAG WARNING FROM NOON CDT /11 AM MDT/ TODAY TO 8 PM CDT /7
PM MDT/ THIS EVENING FOR NEZ204-206-209-210-219.

&&

$$

SHORT TERM...CDC
LONG TERM...JACOBS
AVIATION...CDC
FIRE WEATHER...CDC







AREA FORECAST DISCUSSION

NWS HASTINGS NE

 552 AM CDT SUN APR 28 2013

.UPDATE...
ISSUED AT 544 AM CDT SUN APR 28 2013

UPDATED THE FORECAST TO INCLUDE MENTION OF 1 MILE WITH THE FOG IN
THE FAR SOUTHEAST THIS MORNING AND TO INCLUDE SPRINKLES DOWN TO
THE STATE LINE LATE TONIGHT AS MORE MODELS ARE INDICATING SOME
POSSIBLE QPF...BUT AIR SHOULD BE SO DRY THAT SPRINKLE SHOULD
SUFFICE FARTHER TO THE SOUTH.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 515 AM CDT SUN APR 28 2013

BIGGEST CHALLENGE WILL BE DETERMINING EXTENT OF SOME POTENTIAL FOG
AND STRATUS IN THE SOUTHEASTERN CWA THIS MORNING...PLUS THE
POTENTIAL OF ISOLATED THUNDERSTORMS LATE THIS AFTERNOON/EVENING
NORTHEAST/EAST...AND ALSO A CHANCE OF RAIN LATE TONIGHT.
ALSO...DETERMINING THE HIGH TEMPERATURE TODAY COULD BE A BIT TRICKY.
ALSO...WE WILL BE APPROACHING ELEVATED FIRE DANGER FOR ROUGHLY OUR
NORTHWESTERN QUADRANT OF THE CWA.

THE HRRR WAS SPOT ON WITH FOG AND STRATUS YESTERDAY. WITH THE BEST
TRANSPORT OF MOISTURE SHIFTED SOUTHEAST...THE HRRR APPEARS TO BE ON
TRACK WITH DEVELOPING STRATUS AND FOG TO THE SOUTH. CURRENT
INTERPOLATIONS STILL CLIP US WITH STRATUS AND FOG IN OUR SOUTHEAST
EARLY THIS MORNING...MAINLY AFFECTING OUR 5 SOUTHEASTERN-MOST
COUNTIES. THIS IS EXTREMELY SHALLOW AND SHOULD NOT TAKE LONG TO BURN
OFF BY MID-MORNING.

THE DRY LINE STILL LOOKS LIKE IT WILL BE ON ITS WAY EAST...BUT WILL
STALL IN OUR CWA BEFORE A COLD FRONT MAKES ITS WAY SOUTH ACROSS THE
CWA...COMING FROM THE NORTHERN PLAINS. WITH LOWERING DEWPOINTS FOR
MUCH OF THE CWA...ALONG WITH THE POTENTIAL FOR COMPRESSIONAL WARMING
AND VERY WARM 850 MB TEMPERATURES...I HAVE INCREASED HIGH
TEMPERATURES SIGNIFICANTLY...WELL INTO THE MID 80S. JUDGING BY
RECENT MODEL PERFORMANCE...THIS IS THE DIRECTION TO TAKE.

ALSO...WE COULD GET AN ISOLATED THUNDERSTORM AS THE COLD FRONT MAKES
ITS WAY SOUTH...ESPECIALLY NORTHEAST/EAST WHERE INSTABILITY IS A
LITTLE HIGHER. BULK SHEAR WILL BE MARGINAL FOR SEVERE WEATHER...BUT
WE SHOULD HAVE JUST ENOUGH INSTABILITY TO THROW IN A MENTION OF
PERHAPS SOME HAIL UP TO THE SIZE OF NICKELS ALONG AND EAST OF
HIGHWAY 14.

A MID-LEVEL WAVE COULD GIVE US POST-FRONTAL SHOWER ACTIVITY IN THE
NORTH. THERE DOES NOT APPEAR TO BE ENOUGH MID-LEVEL INSTABILITY TO
SUPPORT THUNDER. ENSEMBLES SUGGEST RAIN POTENTIALLY FARTHER
SOUTH...BUT THIS DOES NOT APPEAR TO BE A POPULAR SOLUTION ON HIGH
RESOLUTION SHORT RANGE MODELS...SO I WILL CONTINUE TO FOCUS CHANCES
IN OUR NORTHERN CWA. THE 06Z RUN DOES INDICATE POSSIBLE RAIN AS FAR
SOUTH AS THE STATE BORDER...POSSIBLY HELPED BY A WEAK AREA OF LEFT
INDUCED BY THE RIGHT REAR QUADRANT OF AN EXTREMELY MODELS JET
STREAK.

.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 515 AM CDT SUN APR 28 2013

ALTHOUGH UNCERTAINTY REMAINS HIGH IN THE DETAILS...THE GENERAL
THEME OF THIS 6-DAY PERIOD HAS CHANGED LITTLE OVER THE PAST 24
HOURS...WITH AT LEAST ONE MORE DAY OF ABOVE NORMAL WARMTH ON
MONDAY FOLLOWED BY THE PASSAGE OF A STRONG COLD FRONT
TUESDAY/TUESDAY NIGHT...WITH WELL BELOW NORMAL TEMPS THEN
PREVAILING THROUGH THE REMAINDER OF THE WEEK...ALTHOUGH THE JURY
IS STILL OUT ON JUST HOW COLD. PRECIP-WISE...ALL OR PART OF THE
CWA NOW HAS POPS MENTIONED FOR 9 CONSECUTIVE FORECAST PERIODS FROM
TUESDAY AFTERNOON THROUGH SATURDAY. THIS IS NOT AN IDEAL SITUATION
FOR PUBLIC FORECAST PRODUCTS AS IT OFTEN CREATES THE IMPRESSION
THAT IT WILL BE WETTER THAN IT ACTUALLY ENDS UP BEING...BUT GIVEN
MODEL VARIABILITY ITS JUST THE WAY IT IS FOR NOW. IN ALL REALITY
THOUGH...SOME OF THESE POPS MAY EVENTUALLY BE REDUCED/CUT IN
LATER FORECASTS...AS MODELS CONTINUE TO VARY CONSIDERABLY FROM
RUN-TO-RUN WITH THE PLACEMENT/LIKELIHOOD OF PRECIP POTENTIAL
BEYOND WEDNESDAY NIGHT. AT THIS POINT...BY FAR THE BEST CHANCES
FOR WIDESPREAD RAIN...AND POSSIBLY EVEN SOME SNOW MIXED
IN...OCCURS BETWEEN TUESDAY NIGHT AND WEDNESDAY NIGHT...WITH
UNCERTAINTY RAMPING UP THEREAFTER. THERE ALSO REMAINS A RISK FOR
STRONG/SEVERE STORMS TUESDAY AFTERNOON BUT LIKELY MORE SO TUESDAY
EVENING. ON TO THE DETAILS...

MONDAY/MONDAY NIGHT...CONFIDENCE REMAINS REASONABLY HIGH IN A DRY
24 HOURS. VARIOUS 00Z MODELS SUCH AS THE NAM/GFS/ECMWF AGREE THAT
THE LARGE SCALE PICTURE ALOFT FEATURES QUASI-ZONAL FLOW...AS ONE
LOW AMPLITUDE SHORTWAVE TROUGH DEPARTS EAST OF THE CWA DURING THE
DAY...WHILE UPSTREAM AN UPPER JET STREAK STARTS CARVING OUT
LARGER...BROADER TROUGH OVER THE NORTHERN ROCKIES/NORTHERN PLAINS.
RIGHT AWAY IN THE MORNING...IT COULD BE A CLOSE CALL WHETHER OR
NOT A BRIEF PERIOD OF LINGERING SPRINKLES/LIGHT SHOWERS FROM THE
SUNDAY NIGHT PERIOD COULD STILL BE SKIRTING EASTERN ZONES...BUT
VARIOUS MODELS INCLUDING REFLECTIVITY PROG FROM 4 KM WRF-NMM SHOVE
THIS ACTIVITY EAST BY 12Z SO WILL KEEP THE OFFICIAL MORNING PERIOD
PRECIP-FREE. LATER IN THE DAY...MODELS SUCH AS THE NAM BUILD A
HEALTHY AREA OF 2000+ J/KG SURFACE-BASED CAPE IN SOUTHEAST
COUNTIES...BUT NOT THINKING MUCH OF A THUNDERSTORM THREAT DUE TO
LIMITED FORCING AND PLENTY OF CAPPING EVIDENT IN FORECAST
SOUNDINGS. FURTHERMORE...THE MAGNITUDE OF MODELED INSTABILITY IS
LIKELY A BIT OVERDONE DUE TO OVERDONE SURFACE DEW POINT VALUES.
ASSUMING NO CONVECTION FIRES...IT SHOULD BE A QUIET AND MILD DAY
AS SURFACE BREEZES GENERALLY 10-15 MPH TRANSITION FROM EASTERLY TO
SOUTHERLY. GIVEN SLIGHTLY COOLER 850MB TEMPS AND LESS FAVORABLE
MIXING THAN TODAY...ANTICIPATE A SLIGHTLY COOLER MONDAY...AND MADE
LITTLE CHANGE TO HIGHS RANGING FROM MID 70S FAR NORTH TO LOW 80S
SOUTHWEST. LATE MONDAY NIGHT...THERE IS DECENT MODEL CONSENSUS
THAT THE LEADING EDGES OF THE COLD FRONT RACES SOUTHEAST INTO THE
NORTHWESTERN CWA BEFORE SUNRISE...ALTHOUGH THE NAM/GFS SEEM TO BE
FASTER WITH THIS FRONTAL INVASION THAN THE ECMWF. THE LATEST 06Z
NAM IS NOW SUGGESTING A NARROW LINE OF SHOWS/STORMS COULD BRUSH
FAR NORTHERN ZONES LATE MONDAY NIGHT JUST BEHIND THIS FRONT...BUT
WITH LIMITED SUPPORT FROM OTHER SOLUTIONS WILL OMIT ANY PRECIP
MENTION FOR NOW ALTHOUGH IT BEARS WATCHING. MADE LITTLE CHANGE TO
LOW TEMPS WITH LOW-MID 50S MOST AREAS EXCEPT UPPER 40S FAR
NORTHWEST.

TUESDAY/TUESDAY NIGHT...THINGS BECOME MORE ACTIVE ITS JUST A
MATTER OF HOW MUCH SO. ALOFT...THE NORTHERN ROCKIES/NORTHERN
PLAINS TROUGH AMPLIFIES IN A POSITIVELY TILTED FASHION...WHILE IN
THE LOW LEVELS THE FAIRLY STRONG COLD FRONT CONTINUES TO SWEEP
SOUTHWARD ACROSS THE CWA...AND HAVE INCREASED NORTH-NORTHEAST
SUSTAINED WIND SPEEDS TO AROUND 20 MPH IN ITS WAKE. FOR SOME
REASON...THE 00Z ECMWF IS STARTING TO LOOK LIKE MORE OF AN OUTLIER
WITH ITS SLOWER COLD FRONTAL PASSAGE...ALTHOUGH THE NAM MAY BE A
BIT TOO AGGRESSIVE. THIS UNCERTAINTY IN THE MAGNITUDE OF DAYTIME COLD
AIR ADVECTION RESULTS IN QUITE A BIT OF UNCERTAINTY IN HIGH
TEMPS...AND COULD EASILY SEE CURRENT FORECAST BEING 5-10 DEGREES
OFF FROM CURRENTLY ADVERTISED VALUES...WHICH ARE A MULTI-MODEL
BLEND. LEANING TOWARD THE FASTER COLD AIR INVASION...NUDGED DOWN
HIGHS ROUGHLY 3-4 DEGREES FROM PREVIOUS...AIMING FOR A DECENT
GRADIENT FROM NEAR 60 FAR NORTH TO UPPER 70S FAR SOUTHEAST. AS FOR
CONVECTIVE POTENTIAL...HELD OFF ANY MENTION OF DAYTIME STORMS
UNTIL POST-21Z...AND KEPT THE EXACT SAME AREA FROM PREVIOUS
FORECAST MAINLY SOUTH OF A YORK-ALMA LINE IN CLOSEST PROXIMITY TO
THE SURFACE FRONT. HOWEVER...IF THE FASTER FRONTAL SOLUTIONS SUCH
AS THE NAM VERIFY THEN THE PRIMARY LOW LEVEL INSTABILITY AXIS AND
RESULTANT RISK FOR POTENTIALLY NEAR-SURFACE BASED STORMS WOULD
ACTUALLY FOCUS SOUTHEAST OF THE CWA. THIS COULD BE A CLOSE CALL.
OF GREATER CONFIDENCE AT THIS POINT IS AN INCREASE IN COVERAGE OF
EVENING/OVERNIGHT PRECIPITATION WELL-BEHIND THE SURFACE
FRONT...AS LARGE SCALE MID LEVEL CONVERGENCE MOVES IN FROM THE
NORTHWEST. EVEN IF THE CWA IS SPARED SURFACE-BASED STORMS...IT
STILL LOOKS LIKE A FAIRLY AGGRESSIVE DEVELOPMENT OF AT LEAST
SLIGHTLY ELEVATED STORMS WILL FLARE UP NEAR OR SHORTLY AFTER
SUNSET IN RESPONSE TO INCREASING MOISTURE TRANSPORT/WIND
CONVERGENCE INTO THE MID-LEVEL FRONTAL ZONE EVIDENT AT 700MB.
WHILE HAIL WOULD LIKELY BE THE MAIN THREAT WITH THESE STORMS...THE
MAGNITUDE OF THE SEVERE RISK WILL ULTIMATELY DEPEND ON THE AMOUNT
OF ELEVATED INSTABILITY...WITH THE LATEST NAM ONLY ADVERTISING
LESS THAN 500 J/KG IN THE 850-700MB LAYER...BUT THE GFS STILL
CLOSER TO 1000 J/KG. DEEP LAYER SHEAR WILL BE PLENTY STRONG TO
SUPPORT AT LEAST MARGINAL SEVERE...AVERAGING AROUND 50KT.
CERTAINLY THE MAIN SEVERE THREAT AREA SHOULD FOCUS ACROSS ROUGHLY
THE SOUTHEAST 1/3 OF THE CWA...AND WILL BE MAKING LITTLE CHANGE
TO HAZARDOUS WEATHER OUTLOOK WORDING. EVEN NORTH OF THE MAIN
THUNDERSTORM AREA...WIDESPREAD RAIN SHOWERS SHOULD BREAK OUT
DURING THE NIGHT...AND POPS WERE RAISED TO 70 PERCENT ACROSS
NEARLY THE ENTIRE CWA. ALTHOUGH THE NAM/GFS THERMAL PROFILES
SUGGEST THAT SOME WET SNOW COULD MIX IN WITH RAIN MAINLY IN FAR
NORTHWEST ZONES LATE IN THE NIGHT...WILL KEEP PRECIP TYPE AS ALL
RAIN FOR NOW...DESPITE LOW TEMPS AIMED FROM MID 30S NORTHWEST TO
MID 40S SOUTHEAST.

WEDNESDAY/WEDNESDAY NIGHT...BY THIS TIME THE CWA IS FIRMLY IN THE
GRIPS OF THE COLDER REGIME. THE 00Z ECMWF/GFS RUNS ARE IN BETTER
AGREEMENT THAN 24 HOURS AGO ON THE SYNOPTIC SCENE...AS THEY BOTH
SLOWLY SHIFT THE INCREASINGLY-AMPLIFIED BUT STILL POSITIVELY
TILTED MID-UPPER TROUGH FROM THE NORTHERN PLAINS/CENTRAL ROCKIES
INTO THE CENTRAL PLAINS...WHILE AT THE SURFACE BREEZY NORTH WINDS
PERSIST. THE DOWNWARD NUDGING TO DAYTIME HIGHS CONTINUES...AND NOW
HAVE ALL BUT THE FAR SOUTHEAST CWA ONLY TOPPING OUT SOMEWHERE IN
THE 40S...WITH FURTHER DOWNWARD NUDGES STILL VERY MUCH POSSIBLE
GIVEN THAT PRECIP IS STILL EXPECTED TO BE FAIRLY WIDESPREAD DURING
THE DAY AS THE SOUTHWEST-NORTHEAST ORIENTED MID LEVEL
FRONTOGENETIC ZONE CENTERS OVERHEAD. AT LEAST FOR ONE MORE
FORECAST CYCLE...HAVE LEFT DAYTIME PRECIP TYPE AS RAIN-
ONLY...ALTHOUGH ITS BECOMING INCREASINGLY LIKELY THAT AT LEAST A
MIX WITH SNOW MAY SOON NEED INSERTED ESPECIALLY IN NORTHWEST
AREAS...ESPECIALLY IF HIGH TEMPS CONTINUE A DOWNWARD TREND. BY
THIS TIME INSTABILITY SHOULD BE MINIMAL EVEN IN SOUTHEAST COUNTIES
AND WILL LEAVE OUT THUNDER. POPS WERE UPPED TO 60 PERCENT
LIKELIES IN MOST AREAS...AS THIS IS SHAPING UP TO BE A RATHER WET
AND VERY RAW FIRST DAY OF MAY. WEDNESDAY NIGHT...KEPT AT LEAST
30-50 POPS GOING ALL AREAS FOR A RAIN/SNOW MIX WITH A LIGHT SNOW
ACCUMULATION NOT OUT OF THE QUESTION...ALTHOUGH BOTH THE ECMWF/GFS
ARE IN DECENT AGREEMENT PUSHING PRECIP OUT FROM NORTHWEST-
SOUTHEAST AS THE NIGHT WEARS ON. KEPT LOW TEMPS BARELY ABOVE
FREEZING ACROSS MOST OF THE CWA WEDNESDAY NIGHT...BUT ANY FROST
THREAT WOULD SEEM VERY MINIMAL GIVEN ONGOING PRECIP AND CONTINUED
MODEST NORTH BREEZES.

TURNING TO THE THURSDAY THROUGH SATURDAY TIME FRAME IN LESS
DETAILED FASHION...THE ONE BIT OF GOOD NEWS IS THAT THE ECWMF/GFS
SOLUTIONS ARE NOW IN INCREDIBLY GOOD AGREEMENT...AT LEAST FOR NOW...ON
THE EVOLUTION OF THE TIGHTLY WOUND CLOSED MID LEVEL LOW THAT IS
FORECAST TO DEVELOP ACROSS THE CENTRAL CONUS AS THE PARENT LARGE
SCALE TROUGH AXIS RUNS INTO A SOLID WALL IN THE FORM OF A STOUT
OMEGA BLOCK RIDGE OVER THE EASTERN CONUS. THE BEGINNING STAGES OF
THIS CLOSING OFF PROCESS TAKES PLACE THURS/THURS NIGHT...GENERALLY
CENTERED SOMEWHERE BETWEEN NORTHERN OK AND EASTERN KS. THIS IS
FARTHER EAST IN THE ECMWF FROM PREVIOUS RUNS...WITH THIS MODEL NOW
ACTUALLY KEEPING MOST OF THE CWA DRY FROM THURS AFTERNOON THROUGH
FRIDAY EVENING. HOWEVER...GIVEN PLENTY OF UNCERTAINTY IN THIS
LATEST SOLUTION WILL KEEP LOW POPS FOR EITHER CHILLY RAIN OR A
RAIN/SNOW MIX GOING ACROSS PART OR ALL OF THE CWA THIS ENTIRE TIME
FOR NOW. BY FRIDAY NIGHT INTO SATURDAY...BOTH OF THESE MODELS LIFT
THE CLOSED LOW BACK NORTH FROM MO TOWARD IA...WITH EVEN THE ECMWF
WRAPPING PRECIP CHANCES WESTWARD BACK INTO AT LEAST THE EASTERN
CWA BY THIS TIME. DAILY/NIGHTLY TEMPERATURES WILL DEPEND SO MUCH
ON WHETHER OR NOT WIDESPREAD CLOUDS AND/OR PRECIP ARE
PRESENT...BUT AT LEAST FOR NOW CONTINUED THE DOWNWARD TREND FOR
HIGH TEMPS THURS-SAT...WITH MAINLY UPPER 40S NOW THURS AND LOW 50S
FRI-SAT. OVERNIGHT LOWS BOTH FRI AND SAT MORNING ARE FORECAST
RIGHT AROUND OR JUST BELOW THE 32 DEGREE FREEZING MARK...BUT
HOLDING ABOVE THE 28 DEGREE HARD FREEZE THRESHOLD. AT THE VERY
LEAST...MAY EVENTUALLY HAVE TO INSERT A FROST MENTION FOR FRIDAY
MORNING...BUT CONFIDENCE IS TOO LOW AT THIS TIME RANGE...AND THERE
ARE ALREADY PLENTY MORE IMMEDIATE ISSUES TO DEAL WITH IN THE
SHORTER TERM...SO WILL NOT EXPLICITLY INTRODUCE FROST/FREEZE
CONCERNS IN THE FORECAST PRODUCTS JUST YET. HOWEVER...ITS CERTAINLY
NOT OUT OF THE QUESTION THAT AT LEAST ONE NIGHT MID-LATE NEXT
WEEK COULD REQUIRE A FROST/FREEZE HEADLINE.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 544 AM CDT SUN APR 28 2013

ONLY MID-HIGH LEVEL SKY COVER FOR THIS FORECAST. AS THE PRESSURE
GRADIENT INCREASES BY THIS AFTERNOON...A BIT OF A GUST IS POSSIBLE
OUT OF THE WEST AS A DRY LINE MOVES EAST INTO THE AREA AND A COLD
FRONT APPROACHES FROM THE NORTH. SOME THUNDERSTORMS ARE POSSIBLE
TO THE NORTHEAST...BUT SHOULD REMAIN OUT OF THE AREA. COULD SEE
ISOLATED SPRINKLES LATE TONIGHT...BUT CHANCES ARE SO LOW THAT THIS
WAS LEFT OUT OF THE FORECAST AND WOULD BE OF LITTLE SIGNIFICANCE
ANYWAY.

&&

.FIRE WEATHER...
ISSUED AT 515 AM CDT SUN APR 28 2013

FOR TODAY...THE DRY LINE STILL LOOKS LIKE IT WILL BE ON ITS WAY
EAST...BUT WILL STALL IN OUR CWA BEFORE A COLD FRONT MAKES ITS WAY
SOUTH ACROSS THE CWA...COMING FROM THE NORTHERN PLAINS. WITH
LOWERING DEWPOINTS FOR MUCH OF THE CWA...ALONG WITH THE POTENTIAL
FOR COMPRESSIONAL WARMING AND VERY WARM 850 MB TEMPERATURES...I
HAVE INCREASED HIGH TEMPERATURES SIGNIFICANTLY...WELL INTO THE MID
80S. RELATIVE HUMIDITY SHOULD BE SOLIDLY DRY FOR ITS PART TOWARD
CRITICAL FIRE WEATHER...BUT THE WINDS WILL BE LACKING A BIT...WITH
THE MOST POTENTIAL FOR FIRE ISSUES COMING FROM THE GUSTS AS THE
COLD FRONT MAKES ITS WAY TOWARD THE NORTHWESTERN CWA BY MID-LATE
AFTERNOON.

&&

.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&

$$

UPDATE...HEINLEIN
SHORT TERM...HEINLEIN
LONG TERM...PFANNKUCH
AVIATION...HEINLEIN
FIRE WEATHER...HEINLEIN





AREA FORECAST DISCUSSION

NWS HASTINGS NE

 519 AM CDT SUN APR 28 2013

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 515 AM CDT SUN APR 28 2013

BIGGEST CHALLENGE WILL BE DETERMINING EXTENT OF SOME POTENTIAL FOG
AND STRATUS IN THE SOUTHEASTERN CWA THIS MORNING...PLUS THE
POTENTIAL OF ISOLATED THUNDERSTORMS LATE THIS AFTERNOON/EVENING
NORTHEAST/EAST...AND ALSO A CHANCE OF RAIN LATE TONIGHT.
ALSO...DETERMINING THE HIGH TEMPERATURE TODAY COULD BE A BIT TRICKY.
ALSO...WE WILL BE APPROACHING ELEVATED FIRE DANGER FOR ROUGHLY OUR
NORTHWESTERN QUADRANT OF THE CWA.

THE HRRR WAS SPOT ON WITH FOG AND STRATUS YESTERDAY. WITH THE BEST
TRANSPORT OF MOISTURE SHIFTED SOUTHEAST...THE HRRR APPEARS TO BE ON
TRACK WITH DEVELOPING STRATUS AND FOG TO THE SOUTH. CURRENT
INTERPOLATIONS STILL CLIP US WITH STRATUS AND FOG IN OUR SOUTHEAST
EARLY THIS MORNING...MAINLY AFFECTING OUR 5 SOUTHEASTERN-MOST
COUNTIES. THIS IS EXTREMELY SHALLOW AND SHOULD NOT TAKE LONG TO BURN
OFF BY MID-MORNING.

THE DRY LINE STILL LOOKS LIKE IT WILL BE ON ITS WAY EAST...BUT WILL
STALL IN OUR CWA BEFORE A COLD FRONT MAKES ITS WAY SOUTH ACROSS THE
CWA...COMING FROM THE NORTHERN PLAINS. WITH LOWERING DEWPOINTS FOR
MUCH OF THE CWA...ALONG WITH THE POTENTIAL FOR COMPRESSIONAL WARMING
AND VERY WARM 850 MB TEMPERATURES...I HAVE INCREASED HIGH
TEMPERATURES SIGNIFICANTLY...WELL INTO THE MID 80S. JUDGING BY
RECENT MODEL PERFORMANCE...THIS IS THE DIRECTION TO TAKE.

ALSO...WE COULD GET AN ISOLATED THUNDERSTORM AS THE COLD FRONT MAKES
ITS WAY SOUTH...ESPECIALLY NORTHEAST/EAST WHERE INSTABILITY IS A
LITTLE HIGHER. BULK SHEAR WILL BE MARGINAL FOR SEVERE WEATHER...BUT
WE SHOULD HAVE JUST ENOUGH INSTABILITY TO THROW IN A MENTION OF
PERHAPS SOME HAIL UP TO THE SIZE OF NICKELS ALONG AND EAST OF
HIGHWAY 14.

A MID-LEVEL WAVE COULD GIVE US POST-FRONTAL SHOWER ACTIVITY IN THE
NORTH. THERE DOES NOT APPEAR TO BE ENOUGH MID-LEVEL INSTABILITY TO
SUPPORT THUNDER. ENSEMBLES SUGGEST RAIN POTENTIALLY FARTHER
SOUTH...BUT THIS DOES NOT APPEAR TO BE A POPULAR SOLUTION ON HIGH
RESOLUTION SHORT RANGE MODELS...SO I WILL CONTINUE TO FOCUS CHANCES
IN OUR NORTHERN CWA. THE 06Z RUN DOES INDICATE POSSIBLE RAIN AS FAR
SOUTH AS THE STATE BORDER...POSSIBLY HELPED BY A WEAK AREA OF LEFT
INDUCED BY THE RIGHT REAR QUADRANT OF AN EXTREMELY MODELS JET
STREAK.

.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 515 AM CDT SUN APR 28 2013

ALTHOUGH UNCERTAINTY REMAINS HIGH IN THE DETAILS...THE GENERAL
THEME OF THIS 6-DAY PERIOD HAS CHANGED LITTLE OVER THE PAST 24
HOURS...WITH AT LEAST ONE MORE DAY OF ABOVE NORMAL WARMTH ON
MONDAY FOLLOWED BY THE PASSAGE OF A STRONG COLD FRONT
TUESDAY/TUESDAY NIGHT...WITH WELL BELOW NORMAL TEMPS THEN
PREVAILING THROUGH THE REMAINDER OF THE WEEK...ALTHOUGH THE JURY
IS STILL OUT ON JUST HOW COLD. PRECIP-WISE...ALL OR PART OF THE
CWA NOW HAS POPS MENTIONED FOR 9 CONSECUTIVE FORECAST PERIODS FROM
TUESDAY AFTERNOON THROUGH SATURDAY. THIS IS NOT AN IDEAL SITUATION
FOR PUBLIC FORECAST PRODUCTS AS IT OFTEN CREATES THE IMPRESSION
THAT IT WILL BE WETTER THAN IT ACTUALLY ENDS UP BEING...BUT GIVEN
MODEL VARIABILITY ITS JUST THE WAY IT IS FOR NOW. IN ALL REALITY
THOUGH...SOME OF THESE POPS MAY EVENTUALLY BE REDUCED/CUT IN
LATER FORECASTS...AS MODELS CONTINUE TO VARY CONSIDERABLY FROM
RUN-TO-RUN WITH THE PLACEMENT/LIKELIHOOD OF PRECIP POTENTIAL
BEYOND WEDNESDAY NIGHT. AT THIS POINT...BY FAR THE BEST CHANCES
FOR WIDESPREAD RAIN...AND POSSIBLY EVEN SOME SNOW MIXED
IN...OCCURS BETWEEN TUESDAY NIGHT AND WEDNESDAY NIGHT...WITH
UNCERTAINTY RAMPING UP THEREAFTER. THERE ALSO REMAINS A RISK FOR
STRONG/SEVERE STORMS TUESDAY AFTERNOON BUT LIKELY MORE SO TUESDAY
EVENING. ON TO THE DETAILS...

MONDAY/MONDAY NIGHT...CONFIDENCE REMAINS REASONABLY HIGH IN A DRY
24 HOURS. VARIOUS 00Z MODELS SUCH AS THE NAM/GFS/ECMWF AGREE THAT
THE LARGE SCALE PICTURE ALOFT FEATURES QUASI-ZONAL FLOW...AS ONE
LOW AMPLITUDE SHORTWAVE TROUGH DEPARTS EAST OF THE CWA DURING THE
DAY...WHILE UPSTREAM AN UPPER JET STREAK STARTS CARVING OUT
LARGER...BROADER TROUGH OVER THE NORTHERN ROCKIES/NORTHERN PLAINS.
RIGHT AWAY IN THE MORNING...IT COULD BE A CLOSE CALL WHETHER OR
NOT A BRIEF PERIOD OF LINGERING SPRINKLES/LIGHT SHOWERS FROM THE
SUNDAY NIGHT PERIOD COULD STILL BE SKIRTING EASTERN ZONES...BUT
VARIOUS MODELS INCLUDING REFLECTIVITY PROG FROM 4 KM WRF-NMM SHOVE
THIS ACTIVITY EAST BY 12Z SO WILL KEEP THE OFFICIAL MORNING PERIOD
PRECIP-FREE. LATER IN THE DAY...MODELS SUCH AS THE NAM BUILD A
HEALTHY AREA OF 2000+ J/KG SURFACE-BASED CAPE IN SOUTHEAST
COUNTIES...BUT NOT THINKING MUCH OF A THUNDERSTORM THREAT DUE TO
LIMITED FORCING AND PLENTY OF CAPPING EVIDENT IN FORECAST
SOUNDINGS. FURTHERMORE...THE MAGNITUDE OF MODELED INSTABILITY IS
LIKELY A BIT OVERDONE DUE TO OVERDONE SURFACE DEW POINT VALUES.
ASSUMING NO CONVECTION FIRES...IT SHOULD BE A QUIET AND MILD DAY
AS SURFACE BREEZES GENERALLY 10-15 MPH TRANSITION FROM EASTERLY TO
SOUTHERLY. GIVEN SLIGHTLY COOLER 850MB TEMPS AND LESS FAVORABLE
MIXING THAN TODAY...ANTICIPATE A SLIGHTLY COOLER MONDAY...AND MADE
LITTLE CHANGE TO HIGHS RANGING FROM MID 70S FAR NORTH TO LOW 80S
SOUTHWEST. LATE MONDAY NIGHT...THERE IS DECENT MODEL CONSENSUS
THAT THE LEADING EDGES OF THE COLD FRONT RACES SOUTHEAST INTO THE
NORTHWESTERN CWA BEFORE SUNRISE...ALTHOUGH THE NAM/GFS SEEM TO BE
FASTER WITH THIS FRONTAL INVASION THAN THE ECMWF. THE LATEST 06Z
NAM IS NOW SUGGESTING A NARROW LINE OF SHOWS/STORMS COULD BRUSH
FAR NORTHERN ZONES LATE MONDAY NIGHT JUST BEHIND THIS FRONT...BUT
WITH LIMITED SUPPORT FROM OTHER SOLUTIONS WILL OMIT ANY PRECIP
MENTION FOR NOW ALTHOUGH IT BEARS WATCHING. MADE LITTLE CHANGE TO
LOW TEMPS WITH LOW-MID 50S MOST AREAS EXCEPT UPPER 40S FAR
NORTHWEST.

TUESDAY/TUESDAY NIGHT...THINGS BECOME MORE ACTIVE ITS JUST A
MATTER OF HOW MUCH SO. ALOFT...THE NORTHERN ROCKIES/NORTHERN
PLAINS TROUGH AMPLIFIES IN A POSITIVELY TILTED FASHION...WHILE IN
THE LOW LEVELS THE FAIRLY STRONG COLD FRONT CONTINUES TO SWEEP
SOUTHWARD ACROSS THE CWA...AND HAVE INCREASED NORTH-NORTHEAST
SUSTAINED WIND SPEEDS TO AROUND 20 MPH IN ITS WAKE. FOR SOME
REASON...THE 00Z ECMWF IS STARTING TO LOOK LIKE MORE OF AN OUTLIER
WITH ITS SLOWER COLD FRONTAL PASSAGE...ALTHOUGH THE NAM MAY BE A
BIT TOO AGGRESSIVE. THIS UNCERTAINTY IN THE MAGNITUDE OF DAYTIME COLD
AIR ADVECTION RESULTS IN QUITE A BIT OF UNCERTAINTY IN HIGH
TEMPS...AND COULD EASILY SEE CURRENT FORECAST BEING 5-10 DEGREES
OFF FROM CURRENTLY ADVERTISED VALUES...WHICH ARE A MULTI-MODEL
BLEND. LEANING TOWARD THE FASTER COLD AIR INVASION...NUDGED DOWN
HIGHS ROUGHLY 3-4 DEGREES FROM PREVIOUS...AIMING FOR A DECENT
GRADIENT FROM NEAR 60 FAR NORTH TO UPPER 70S FAR SOUTHEAST. AS FOR
CONVECTIVE POTENTIAL...HELD OFF ANY MENTION OF DAYTIME STORMS
UNTIL POST-21Z...AND KEPT THE EXACT SAME AREA FROM PREVIOUS
FORECAST MAINLY SOUTH OF A YORK-ALMA LINE IN CLOSEST PROXIMITY TO
THE SURFACE FRONT. HOWEVER...IF THE FASTER FRONTAL SOLUTIONS SUCH
AS THE NAM VERIFY THEN THE PRIMARY LOW LEVEL INSTABILITY AXIS AND
RESULTANT RISK FOR POTENTIALLY NEAR-SURFACE BASED STORMS WOULD
ACTUALLY FOCUS SOUTHEAST OF THE CWA. THIS COULD BE A CLOSE CALL.
OF GREATER CONFIDENCE AT THIS POINT IS AN INCREASE IN COVERAGE OF
EVENING/OVERNIGHT PRECIPITATION WELL-BEHIND THE SURFACE
FRONT...AS LARGE SCALE MID LEVEL CONVERGENCE MOVES IN FROM THE
NORTHWEST. EVEN IF THE CWA IS SPARED SURFACE-BASED STORMS...IT
STILL LOOKS LIKE A FAIRLY AGGRESSIVE DEVELOPMENT OF AT LEAST
SLIGHTLY ELEVATED STORMS WILL FLARE UP NEAR OR SHORTLY AFTER
SUNSET IN RESPONSE TO INCREASING MOISTURE TRANSPORT/WIND
CONVERGENCE INTO THE MID-LEVEL FRONTAL ZONE EVIDENT AT 700MB.
WHILE HAIL WOULD LIKELY BE THE MAIN THREAT WITH THESE STORMS...THE
MAGNITUDE OF THE SEVERE RISK WILL ULTIMATELY DEPEND ON THE AMOUNT
OF ELEVATED INSTABILITY...WITH THE LATEST NAM ONLY ADVERTISING
LESS THAN 500 J/KG IN THE 850-700MB LAYER...BUT THE GFS STILL
CLOSER TO 1000 J/KG. DEEP LAYER SHEAR WILL BE PLENTY STRONG TO
SUPPORT AT LEAST MARGINAL SEVERE...AVERAGING AROUND 50KT.
CERTAINLY THE MAIN SEVERE THREAT AREA SHOULD FOCUS ACROSS ROUGHLY
THE SOUTHEAST 1/3 OF THE CWA...AND WILL BE MAKING LITTLE CHANGE
TO HAZARDOUS WEATHER OUTLOOK WORDING. EVEN NORTH OF THE MAIN
THUNDERSTORM AREA...WIDESPREAD RAIN SHOWERS SHOULD BREAK OUT
DURING THE NIGHT...AND POPS WERE RAISED TO 70 PERCENT ACROSS
NEARLY THE ENTIRE CWA. ALTHOUGH THE NAM/GFS THERMAL PROFILES
SUGGEST THAT SOME WET SNOW COULD MIX IN WITH RAIN MAINLY IN FAR
NORTHWEST ZONES LATE IN THE NIGHT...WILL KEEP PRECIP TYPE AS ALL
RAIN FOR NOW...DESPITE LOW TEMPS AIMED FROM MID 30S NORTHWEST TO
MID 40S SOUTHEAST.

WEDNESDAY/WEDNESDAY NIGHT...BY THIS TIME THE CWA IS FIRMLY IN THE
GRIPS OF THE COLDER REGIME. THE 00Z ECMWF/GFS RUNS ARE IN BETTER
AGREEMENT THAN 24 HOURS AGO ON THE SYNOPTIC SCENE...AS THEY BOTH
SLOWLY SHIFT THE INCREASINGLY-AMPLIFIED BUT STILL POSITIVELY
TILTED MID-UPPER TROUGH FROM THE NORTHERN PLAINS/CENTRAL ROCKIES
INTO THE CENTRAL PLAINS...WHILE AT THE SURFACE BREEZY NORTH WINDS
PERSIST. THE DOWNWARD NUDGING TO DAYTIME HIGHS CONTINUES...AND NOW
HAVE ALL BUT THE FAR SOUTHEAST CWA ONLY TOPPING OUT SOMEWHERE IN
THE 40S...WITH FURTHER DOWNWARD NUDGES STILL VERY MUCH POSSIBLE
GIVEN THAT PRECIP IS STILL EXPECTED TO BE FAIRLY WIDESPREAD DURING
THE DAY AS THE SOUTHWEST-NORTHEAST ORIENTED MID LEVEL
FRONTOGENETIC ZONE CENTERS OVERHEAD. AT LEAST FOR ONE MORE
FORECAST CYCLE...HAVE LEFT DAYTIME PRECIP TYPE AS RAIN-
ONLY...ALTHOUGH ITS BECOMING INCREASINGLY LIKELY THAT AT LEAST A
MIX WITH SNOW MAY SOON NEED INSERTED ESPECIALLY IN NORTHWEST
AREAS...ESPECIALLY IF HIGH TEMPS CONTINUE A DOWNWARD TREND. BY
THIS TIME INSTABILITY SHOULD BE MINIMAL EVEN IN SOUTHEAST COUNTIES
AND WILL LEAVE OUT THUNDER. POPS WERE UPPED TO 60 PERCENT
LIKELIES IN MOST AREAS...AS THIS IS SHAPING UP TO BE A RATHER WET
AND VERY RAW FIRST DAY OF MAY. WEDNESDAY NIGHT...KEPT AT LEAST
30-50 POPS GOING ALL AREAS FOR A RAIN/SNOW MIX WITH A LIGHT SNOW
ACCUMULATION NOT OUT OF THE QUESTION...ALTHOUGH BOTH THE ECMWF/GFS
ARE IN DECENT AGREEMENT PUSHING PRECIP OUT FROM NORTHWEST-
SOUTHEAST AS THE NIGHT WEARS ON. KEPT LOW TEMPS BARELY ABOVE
FREEZING ACROSS MOST OF THE CWA WEDNESDAY NIGHT...BUT ANY FROST
THREAT WOULD SEEM VERY MINIMAL GIVEN ONGOING PRECIP AND CONTINUED
MODEST NORTH BREEZES.

TURNING TO THE THURSDAY THROUGH SATURDAY TIME FRAME IN LESS
DETAILED FASHION...THE ONE BIT OF GOOD NEWS IS THAT THE ECWMF/GFS
SOLUTIONS ARE NOW IN INCREDIBLY GOOD AGREEMENT...AT LEAST FOR NOW...ON
THE EVOLUTION OF THE TIGHTLY WOUND CLOSED MID LEVEL LOW THAT IS
FORECAST TO DEVELOP ACROSS THE CENTRAL CONUS AS THE PARENT LARGE
SCALE TROUGH AXIS RUNS INTO A SOLID WALL IN THE FORM OF A STOUT
OMEGA BLOCK RIDGE OVER THE EASTERN CONUS. THE BEGINNING STAGES OF
THIS CLOSING OFF PROCESS TAKES PLACE THURS/THURS NIGHT...GENERALLY
CENTERED SOMEWHERE BETWEEN NORTHERN OK AND EASTERN KS. THIS IS
FARTHER EAST IN THE ECMWF FROM PREVIOUS RUNS...WITH THIS MODEL NOW
ACTUALLY KEEPING MOST OF THE CWA DRY FROM THURS AFTERNOON THROUGH
FRIDAY EVENING. HOWEVER...GIVEN PLENTY OF UNCERTAINTY IN THIS
LATEST SOLUTION WILL KEEP LOW POPS FOR EITHER CHILLY RAIN OR A
RAIN/SNOW MIX GOING ACROSS PART OR ALL OF THE CWA THIS ENTIRE TIME
FOR NOW. BY FRIDAY NIGHT INTO SATURDAY...BOTH OF THESE MODELS LIFT
THE CLOSED LOW BACK NORTH FROM MO TOWARD IA...WITH EVEN THE ECMWF
WRAPPING PRECIP CHANCES WESTWARD BACK INTO AT LEAST THE EASTERN
CWA BY THIS TIME. DAILY/NIGHTLY TEMPERATURES WILL DEPEND SO MUCH
ON WHETHER OR NOT WIDESPREAD CLOUDS AND/OR PRECIP ARE
PRESENT...BUT AT LEAST FOR NOW CONTINUED THE DOWNWARD TREND FOR
HIGH TEMPS THURS-SAT...WITH MAINLY UPPER 40S NOW THURS AND LOW 50S
FRI-SAT. OVERNIGHT LOWS BOTH FRI AND SAT MORNING ARE FORECAST
RIGHT AROUND OR JUST BELOW THE 32 DEGREE FREEZING MARK...BUT
HOLDING ABOVE THE 28 DEGREE HARD FREEZE THRESHOLD. AT THE VERY
LEAST...MAY EVENTUALLY HAVE TO INSERT A FROST MENTION FOR FRIDAY
MORNING...BUT CONFIDENCE IS TOO LOW AT THIS TIME RANGE...AND THERE
ARE ALREADY PLENTY MORE IMMEDIATE ISSUES TO DEAL WITH IN THE
SHORTER TERM...SO WILL NOT EXPLICITLY INTRODUCE FROST/FREEZE
CONCERNS IN THE FORECAST PRODUCTS JUST YET. HOWEVER...ITS CERTAINLY
NOT OUT OF THE QUESTION THAT AT LEAST ONE NIGHT MID-LATE NEXT
WEEK COULD REQUIRE A FROST/FREEZE HEADLINE.

&&

.AVIATION...(FOR THE 06Z KGRI TAF THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 125 AM CDT SUN APR 28 2013

ONLY MID-HIGH LEVEL SKY COVER FOR THIS FORECAST. AS THE PRESSURE
GRADIENT INCREASES BY SUNDAY AFTERNOON...A BIT OF A GUST IS
POSSIBLE OUT OF THE WEST AS A DRY LINE MOVES EAST INTO THE
AREA AND A COLD FRONT APPROACHES FROM THE NORTH. SOME
THUNDERSTORMS ARE POSSIBLE TO THE NORTHEAST...BUT SHOULD REMAIN
OUT OF THE AREA.

&&

.FIRE WEATHER...
ISSUED AT 515 AM CDT SUN APR 28 2013

FOR TODAY...THE DRY LINE STILL LOOKS LIKE IT WILL BE ON ITS WAY
EAST...BUT WILL STALL IN OUR CWA BEFORE A COLD FRONT MAKES ITS WAY
SOUTH ACROSS THE CWA...COMING FROM THE NORTHERN PLAINS. WITH
LOWERING DEWPOINTS FOR MUCH OF THE CWA...ALONG WITH THE POTENTIAL
FOR COMPRESSIONAL WARMING AND VERY WARM 850 MB TEMPERATURES...I
HAVE INCREASED HIGH TEMPERATURES SIGNIFICANTLY...WELL INTO THE MID
80S. RELATIVE HUMIDITY SHOULD BE SOLIDLY DRY FOR ITS PART TOWARD
CRITICAL FIRE WEATHER...BUT THE WINDS WILL BE LACKING A BIT...WITH
THE MOST POTENTIAL FOR FIRE ISSUES COMING FROM THE GUSTS AS THE
COLD FRONT MAKES ITS WAY TOWARD THE NORTHWESTERN CWA BY MID-LATE
AFTERNOON.

&&

.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&

$$

SHORT TERM...HEINLEIN
LONG TERM...PFANNKUCH
AVIATION...HEINLEIN
FIRE WEATHER...HEINLEIN





AREA FORECAST DISCUSSION

NWS NORTH PLATTE NE

 337 AM CDT SUN APR 28 2013
...CORRECTION FOR TYPO...

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 337 AM CDT SUN APR 28 2013

SFC WINDS SHOULD INCREASE FROM THE WEST TOWARD MORNING AHEAD OF A
PACIFIC COLD FRONT FCST TO MOVE THROUGH DURING THE AFTN. THE RAP
SUPPORTS HIGHS IN THE MID 80S AHEAD OF THE FRONT ACROSS SWRN NEB AND
WINDS SHOULD INCREASE TO 15 TO 25 MPH AHEAD AND BEHIND THE FRONT.

FOR TONIGHT...A DISTURBANCE...CURRENTLY ACROSS THE NRN ROCKIES WILL
MOVE THROUGH NRN NEB. K INDICES SUPPORT TSTMS WEST OF HIGHWAY 83.
MOISTURE BELOW 700MB IS VERY LIMITED EAST OF 83 AND LAPSE RATES
NEARLY MOIST ADIABATIC.

.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 337 AM CDT SUN APR 28 2013

GUSTY SOUTHERLY WINDS AND CRITICALLY LOW RELATIVE HUMIDITY VALUES TO
BE EXPECTED ONCE AGAIN MONDAY AFTERNOON...WITH THE POTENTIAL OF
WIDESPREAD RED FLAG CONDITIONS.  FIRE HEADLINES MAY BE NECESSARY
ONCE AGAIN.  A SURFACE TROUGH OF LOW PRESSURE WILL DEEPEN ALONG THE
HIGH PLAINS ON MONDAY...ALLOWING FOR DOWNSLOPING SOUTHWESTERLY TO
WESTERLY WINDS AND HIGHS WELL INTO THE UPPER 70S...IF NOT LOW 80S.
WIND GUSTS WILL LIKELY EXCEED 25 MPH DURING PEAK HEATING AS THE
PRESSURE GRADIENT INCREASES AND STRONG TROPOSPHERIC MIXING
COMMENCES.  PREVIOUS FORECAST HAD HIGHS HANDLED WELL FOR
MONDAY...WITH ONLY MINOR UPWARD TWEAKS NEEDED ACROSS NORTHWESTERN
NEBRASKA...WHERE TEMPERATURES MAY SOAR IN ADVANCE OF A COLD FRONTAL
PASSAGE.  THE FRONT IS CURRENTLY PROGGED TO ARRIVE OVERNIGHT
MONDAY/EARLY TUESDAY...HOWEVER THERE IS LITTLE SUPPORT FOR
PRECIPITATION PRODUCTION INITIALLY.  PROXIMITY SOUNDINGS REVEAL VERY
LITTLE MOISTURE IN THE LOWER LEVELS...THUS WILL CONTINUE THE SILENT
14 POPS THROUGH THE OVERNIGHT.  TEMPERATURES HOWEVER WILL BE
NOTICEABLY COOLER ON TUESDAY...BUT THERE REMAINS DIFFERENCES BETWEEN
THE DETERMINISTIC SOLUTIONS IN THE AMOUNT OF COOLING...THE CONSENSUS
WOULD SUGGEST A 20-25F DECREASE IN HIGHS FROM MONDAY...WILL GO WITH
A RANGE OF HIGHS FROM THE MID 50S TO LOW 60S ACROSS THE CWA.  ALONG
WITH THE COOLER TEMPERATURES...PRECIPITATION CHANCES INCREASE
TUESDAY INTO WEDNESDAY AS A MIDLEVEL SHORTWAVE AND ASSOCIATED RRE OF
A 110 PLUS KT UPPER JET ADVANCES ON THE REGION.  THE HIGHEST QPF
WILL BE TIED TO THE MID-LEVEL FRONTOGENETIC FORCING WHICH SHOULD
BISECT THE CWA FROM SOUTHWEST TO NORTHEAST...WHICH MEANS CHANCES ARE
INCREASING FOR WELCOME WIDESPREAD QPF ACROSS THE HEART OF THE
SANDHILLS.  PTYPE MAY BECOME PROBLEMATIC EARLY ON WEDNESDAY...AS H85
TEMPERATURES ARE SHOWN TO FALL AS COLD AS -3C BY 12Z WEDNESDAY.
WILL INTRODUCE A RAIN/SNOW MIX ACROSS NORTHWEST NEBRASKA FROM
06Z-12Z...BUT NOT EXPECTING ANY ACCUMULATIONS AS GROUND TEMPERATURES
HAVE WARMED GREATLY.  GUIDANCE CAME IN COOLER ONCE AGAIN FOR
WEDNESDAY...AND GIVEN EXPECTED CLOUDY CONDITIONS WITH WEAK OR
NEUTRAL CAA...HIGHS IN THE LOWER 40S SHOULD BE THE NORM.  THE
REMAINDER OF THE EXTENDED FORECAST REMAINS INTERESTING AS A CLOSED
LOW DEVELOPS OVER CENTRAL KANSAS ON THURSDAY...AND THEREAFTER
MEANDERS AIMLESSLY THROUGH THE MISSOURI VALLEY/CORN BELT THROUGH THE
WEEKEND.  WITH BROAD CYCLONIC FLOW REMAINING ACROSS THE CENTRAL
CONUS...WILL MAINTAIN COOLER THAN NORMAL TEMPERATURES INTO NEXT
WEEKEND WITH CONTINUED SLIGHT CHANCES OF PRECIPITATION.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1243 AM CDT SUN APR 28 2013

THROUGH SUNDAY AFTERNOON...SCATTERED HIGH CLOUDINESS WILL MOVE IN
FROM THE WEST IN ADVANCE OF AN APPROACHING UPPER LEVEL
DISTURBANCE. CLOUDS WILL THICKEN SUNDAY EVENING AS THE DISTURBANCE
BEGINS TO TRACK ACROSS NORTHERN NEBRASKA. ISOLATED TO WIDELY
SCATTERED THUNDERSTORMS ARE POSSIBLE SUNDAY EVENING ACROSS
NORTHERN NEBRASKA...AND MAY IMPACT THE KVTN TERMINAL AFTER 02Z
MONDAY WITH CIGS DOWN TO 5000 FT AND VSBYS DOWN TO 4SM. WINDS OVER
THE NEXT 24 HOURS...WILL GRADUALLY SHIFT FROM THE WEST TO THE
NORTH...THEN NORTHEAST. WIND SPEEDS WILL RANGE FROM 10 TO 15 KTS.


&&

.FIRE WEATHER...
ISSUED AT 337 AM CDT SUN APR 28 2013

RED FLAG CONDITIONS SHOULD DEVELOP AHEAD AND BEHIND THE COLD FRONT
FORECAST TO MOVE THROUGH SWRN NEB THIS AFTN. THE RAP AND HRRR ARE
LEADING THE WAY WITH DEW PTS IN THE 20S WHILE THE MOSGUIDE WIND
GUSTS ARE IN THE 20 TO 24 KT RANGE. THE DRIER MODEL DATA AND
STRONGER WIND GUSTS HAVE BEEN VERIFYING BETTER THAN THE WETTER
MODELS WHICH HAVE BEEN AS MUCH AS 10F TOO HIGH WITH DEW POINTS.

&&

.LBF WATCHES/WARNINGS/ADVISORIES...
RED FLAG WARNING FROM NOON CDT /11 AM MDT/ TODAY TO 8 PM CDT /7
PM MDT/ THIS EVENING FOR NEZ204-206-209-210-219.

&&

$$

SHORT TERM...CDC
LONG TERM...JACOBS
AVIATION...CDC
FIRE WEATHER...CDC












AREA FORECAST DISCUSSION

NWS HASTINGS NE

 100 AM CDT SUN APR 28 2013

.UPDATE...
ISSUED AT 1257 AM CDT SUN APR 28 2013

INCLUDED SOME FOG AND STRATUS IN THE SOUTHEASTERN CWA AS THE HRRR
ADVERTISES. THE HRR WAS SPOT ON WITH THE FOG LAST NIGHT...SO
CONTINUING WITH MORE CONFIDENCE IN THE HRRR OVER ANYTHING ELSE.

&&

.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 327 PM CDT SAT APR 27 2013

PLEASANT CONDITIONS IN PLACE ACROSS THE CWA THIS AFTERNOON...SITTING
ON THE BACKSIDE OF AN UPPER LEVEL LOW PRESSURE SYSTEM GRADUALLY
MAKING ITS WAY EAST ACROSS MISSOURI.  AT THE SURFACE...THE CWA IS IN
BETWEEN A TROUGH OF LOW PRESSURE DRAPED THROUGH THE HIGH PLAINS AND
HIGH PRESSURE FROM TX INTO IA...BRINGING SWRLY WINDS...BUT WITH A
WEAK PRESSURE GRADIENT SPEEDS ARE ON THE LIGHTER SIDE.  STARTED OFF
THE DAY WITH A LOT OF FOG AND STRATUS...BUT BY MIDDAY MOST OF THAT
HAD BURNED OFF...LEAVING MOSTLY CLEAR SKIES BEHIND.

THROUGH THE REST OF THE SHORT TERM PERIOD...THE FORECAST REMAINS
DRY...WITH MODELS CONTINUING TO SHOW WEAK SHORTWAVE RIDGING SHIFTING
INTO THE AREA TONIGHT AND SLIDING EAST TOMORROW BETWEEN THE
DEPARTING LOW CURRENTLY OVER MISSOURI AND ANOTHER DISTURBANCE
STARTING TO SWING INTO THE DAKOTAS.  SHOULD START TO SEE A FEW MORE
CLOUDS WORK IN FROM NORTH DURING THE AFTERNOON...OTHERWISE EXPECTING
MOSTLY CLEAR SKIES.  LOOKING AT THE SFC PATTERN...WINDS WILL
CONTINUE OUT OF THE SOUTHWEST...THEN MORE WESTERLY AS A SFC FRONT
ACCOMPANYING THAT UPPER LEVEL DISTURBANCE INCHES CLOSER TO THE CWA.
THERE CONTINUES TO BE SOME MODEL HINT AT SOME LIGHT PRECIP TRYING TO
CREEP INTO NRN PORTIONS OF THE CWA LATE TOMORROW AFTERNOON...BUT
WITHOUT MORE SUPPORT FROM OTHER MODELS...AND FORECAST SOUNDING BEING
PRETTY DRY IN THE LOWER LEVELS...KEPT THINGS DRY.

WILL SEE ANOTHER PUSH OF WARMER AIR ALOFT...AND ALONG WITH GOOD
MIXING POTENTIAL AND SW/WRLY WINDS...EXPECTING ANOTHER BUMP UP IN
TEMPERATURES....WITH HIGHS FORECAST IN THE LOWER 80S.  THE COMBO OF
FORECAST TEMPS AND DEWPOINTS WILL RESULT IN RH VALUES DOWN IN THE
MID TEENS TO MID 20S...BUT WIND SPEEDS REMAINING IN THE 10 TO 15 MPH
RANGE WILL HELP KEEP FIRE WX CONCERNS IN CHECK.

.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 327 PM CDT SAT APR 27 2013

AFTER A WARM START...TEMPERATURES WILL TURN COLDER DURING THE
EXTENDED WITH INTERMITTENT CHCS FOR PCPN UNDER INFLUENCE OF AN
UPPER LOW PRESSURE SYSTEM IN A BLOCKY PATTERN.

SUNDAY NIGHT...A 75KT JET STREAK WILL CROSS THE NORTHERN PLAINS
REGION WITH A LEAD SHORTWAVE TROUGH AND SFC TROUGH/SUBTLE COOL FRONT
ADVANCING SOUTH SUNDAY NIGHT WHILE ANOTHER WAVE TRANSLATES EAST
ACROSS NORTHERN NEB OVERNIGHT.  OUR NORTHERN ZONES COULD SEE SOME
LIGHT PCPN WITH THIS SYSTEM BUT INSTABILITY IS HIT OR MISS HAVE
KEPT THINGS AS SHOWERS ATTM.

SFC RIDGE AXIS WHICH SETTLES IN BEHIND THE BOUNDARY SHIFTS EAST
MONDAY WITH RETURN FLOW SETTING UP AND FRONT LIFTS BACK
NORTH...RESULTING IN ANOTHER DAY OF WARM SPRING TEMPS WELL INTO THE 70S
TO LOWER 80S. A STRONGER WAVE/TROUGH TRANSLATES SOUTHEAST FM
CANADA ACROSS THE NORTHERN PLAINS/DAKOTAS MONDAY NIGHT...SENDING A
STRONGER COLD FRONT SOUTH INTO THE CENTRAL PLAINS. THE NAM REMAINS
THE FASTEST WITH FROPA THAN OTHER MODELS AND HAVE TRENDED TOWARD
ENSEMBLES FOR TIMING WHICH IS FAIRLY CLOSE TO GFS AS WELL. THE
FRONTAL BOUNDARY REACHES OUR SE NEB COUNTIES INTO NC KS MID DAY
TUESDAY. MOISTURE POOLS ALONG THE FRONT AND INSTABILITY
INCREASES...AND GOOD SHEAR IS PRESENT AS WELL ALONG THE
BOUNDARY...ESPECIALLY OVERNIGHT AS THE LLVL JET STRENGTHENS. CHCS FOR
CONVECTION INCREASE BY EVENING AND CONTINUE THRU THE OVERNIGHT
HOURS AND STRONG/SEVERE STORMS ARE POSSIBLE WITH HAIL/WIND THE
PRIMARY HAZARDS IN VCNTY OF BOUNDARY.

MUCH COLDER AIR PUSHES SOUTH BEHIND THE FRONT WEDNESDAY AND IN
DYNAMICS WITH MID LEVEL FRONTOGENESIS AND WAVE MOVING ONTO THE
PLAINS...PCPN CHCS CARRY INTO BOTH WEDNESDAY/WEDNESDAY NIGHT. H85
TEMPS DROP BELOW FREEZING WEDNESDAY AND AS COLD AIR CONTINUES TO
DEEPEN...A R/S MIX LOOKS PROBABLE WEDNESDAY NIGHT AS LLVL TEMPS
COOL. IT LOOKS LIKE THE BRUNT OF THE COOLER AIR ARRIVES ON THE
TAIL END OF THE PCPN...BUT SOMETHING TO WATCH AND FOLLOWED CLOSER
TO MODEL THICKNESS VALUES FOR THE R/S LINE.

THE UPPER TROUGH DEEPENS ACROSS THE INTERIOR CONUS BY THURSDAY IN
A BLOCKING PATTERN WITH AN UPPER RIDGE ALONG THE EAST COAST AND
RIDGING ALONG THE WEST COAST. THE UPPER LOW IS PROGGED TO CLOSE
ACROSS THE CENTRAL PLAINS AND MEANDER ACROSS OUR REGION THROUGH
NEXT WEEKEND. THIS WILL RESULT IN A COLD AND PERIODIC WET PERIOD
THURSDAY THRU SATURDAY. DEPENDING ON TEMP PROFILE R/S IS POSSIBLE
BUT HAVE KEPT THINGS AS MAINLY RAIN ATTM UNTIL THERMAL PROFILE CAN
BE MORE CLOSELY EVALUATED AS SYSTEM AND EXTENDED PERIODS DRAW CLOSER.
WILL ALSO NEED TO MONITOR LOW TEMPS FOR POTENTIAL FOR READINGS
NEAR THE FREEZING MARK.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 125 AM CDT SUN APR 28 2013

ONLY MID-HIGH LEVEL SKY COVER FOR THIS FORECAST. AS THE PRESSURE
GRADIENT INCREASES BY SUNDAY AFTERNOON...A BIT OF A GUST IS
POSSIBLE OUT OF THE WEST AS A DRY LINE MOVES EAST INTO THE
AREA AND A COLD FRONT APPROACHES FROM THE NORTH. SOME
THUNDERSTORMS ARE POSSIBLE TO THE NORTHEAST...BUT SHOULD REMAIN
OUT OF THE AREA.

&&

.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&

$$

UPDATE...HEINLEIN
SHORT TERM...ADO
LONG TERM...FAY
AVIATION...HEINLEIN







AREA FORECAST DISCUSSION

NWS BUFFALO NY

 317 PM EDT SUN APR 28 2013

.SYNOPSIS...
A WEAK AREA OF LOW PRESSURE WILL LIFT NORTHEAST OUT OF THE OHIO
VALLEY AND BRING SHOWERS TO WESTERN NEW YORK THROUGH THIS
EVENING. SCATTERED SHOWERS WILL LINGER LATE TONIGHT AND INTO
MONDAY. AFTER THIS...A PERSISTENT SOUTHERLY FLOW WILL BRING FAIR
AND WARM WEATHER WHICH WILL LAST THROUGH NEXT WEEKEND.

&&

.NEAR TERM /THROUGH MONDAY/...
A CLOSED UPPER LEVEL LOW ACROSS INDIANA WILL SLOWLY MOVE TO THE
EAST THROUGH THIS EVENING. ASSOCIATED WITH THIS IS A LOW LEVEL JET
OF AROUND 40 KNOTS...WITH A STEADY AREA OF SHOWERS ACROSS
NORTHEASTERN OHIO AND WESTERN PENNSYLVANIA WHICH APPEARS TO BE
ASSOCIATED WITH THE LEADING EDGE OF THIS LOW LEVEL JET. THIS AREA OF
SHOWERS WILL CONTINUE TO GRADUALLY SPREAD INTO WESTERN NEW YORK LATE
THIS AFTERNOON THROUGH THIS EVENING. ITS PROGRESS MAY BE A BIT
SLOWER THAN PURE EXTRAPOLATION DUE TO DRYING FROM DOWNSLOPING. THIS
IS WELL CAPTURED BY THE HRRR AND MOST OTHER GUIDANCE...AND THUS HAVE
HIGH CONFIDENCE THAT THIS WILL BRING A 2-3 HOUR PERIOD OF SHOWERS TO
MOST LOCATIONS WEST OF ROCHESTER. AFTER THIS...THIS MOISTURE WILL BE
STRETCHED OUT CAUSING IT TO FALL APART AS IT APPROACHES THE EASTERN
LAKE ONTARIO REGION.

UNTIL THIS REACHES YOUR LOCATION...IT WILL CONTINUE TO BE WARM AND A BIT
BREEZY. TEMPERATURES ARE IN THE LOWER TO MID 70S IN MANY
LOCATIONS...EXPECT ABOUT 10 DEGREES COOLER IN THE SOUTHERN TIER WERE
CLOUDS CAME IN EARLY. EXPECT THE ONSET OF SHOWERS TO CAUSE A BRIEF
PERIOD OF WIND GUSTS TO 35 MPH AND A QUICK DROP IN TEMPERATURES BOTH
DUE TO EVAPORATIONAL COOLING.

AFTER THIS INITIAL ROUND OF SHOWERS MOVES THROUGH...PRECIPITATION
IS EXPECTED TO BE MUCH MORE HIT OR MISS. THIS CAN BE SEEN UPSTREAM
ON RADAR AS WELL...WITH SHOWERS BEHIND IT QUITE SCATTERED IN
NATURE. WITH THE UPPER TROF APPROACHING A SHOWER CANNOT BE RULED OUT
LATE TONIGHT...BUT EXPECT COVERAGE SOMEWHAT SPARSE. ALSO...THERE
WILL BE A LIMITED AMOUNT OF ELEVATED CAPE...WITH AN ISOLATED
THUNDERSTORM NOT COMPLETELY OUT OF THE QUESTION. FOR NOW...WILL WAIT
FOR UPSTREAM LIGHTNING STRIKES BEFORE ADDING THIS INTO THE FORECAST
GIVEN THE MARGINAL NATURE.

TEMPERATURES WILL DROP TONIGHT MAINLY BECAUSE OF EVAPORATIONAL
COOLING RATHER THAN RADIATIONAL COOLING DUE TO PERSISTENT WINDS
AND CLOUD COVER. LOWS WILL RANGE FROM THE UPPER 40S TO LOWER 50S.

ON MONDAY...THE UPPER LOW WILL CONTINUE TO OPEN UP AND LIFT
NORTHWARD. EXPECT A CONTINUING CHANCE FOR SHOWERS IN THE
MORNING...WITH THESE TAPERING OFF FROM WEST TO EAST DURING THE
AFTERNOON HOURS. TEMPERATURES WILL REMAIN ON THE WARM SIDE...WITH
HIGHS MAINLY IN THE 60S. IT COULD BE LOCALLY WARMER IF THE SUN
BREAKS OUT...BUT AT THIS TIME EXPECT THE UPPER LOW TO KEEP SKIES
CLOUDY FOR THE MAJORITY OF THE DAY.

&&

.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY NIGHT/...
THE SURFACE SURFACE LOW WILL LOSE ALMOST ALL INDICATIONS BY MONDAY
NIGHT...ALL THAT REMAINS WILL BE A WEAK TROUGH ALOFT...A 25-35 KNOT
JET AT 850MB AND EXTENDED BUT WEAK CONVERGENCE IN THE LOWER LEVELS.
PRECIPITATION WILL END FROM WEST TO EAST ALTHOUGH THERE WILL BE
LINGERING CHANCE FOR SHOWER ON TUESDAY WITH DAYTIME HEATING.

HIGH PRESSURE AT THE SURFACE WILL REMAIN ANCHORED OFF THE NEW
ENGLAND COAST TUESDAY AND WEDNESDAY. AT THE SAME TIME...A RIDGE OF
HIGH PRESSURE ALOFT WILL STRENGTHEN ACROSS THE OHIO VALLEY AND
EASTERN GREAT LAKES IN RESPONSE TO A TROUGH THAT WILL BE DIGGING
INTO THE UPPER MIDWEST AND PLAINS STATES. THE HIGH SHOULD KEEP US
DRY THROUGH THIS PERIOD...ALTHOUGH WE MAY SEE A FAIR AMOUNT OF
CLOUDS AS A PERSISTENT SOUTH TO SOUTHEAST FLOW AT THE SURFACE TAPS
INTO ATLANTIC MOISTURE. THE REGION WILL ENTER A WARMER PHASE WITH
HIGH TEMPERATURES ON TUESDAY IN THE LOWER TO MID 70S...AND MID TO
UPPER 70S ON WEDNESDAY AS 850MB TEMPS RISE TO A +12C TO +14C RANGE.
SEASONABLY MILD TEMPERATURES WILL BE THE RULE TUESDAY NIGHT AND
WEDNESDAY NIGHT.

&&

.LONG TERM /THURSDAY THROUGH SUNDAY/...
THE GFS AND ECMWF REMAIN IN GOOD AGREEMENT REGARDING THE POSITION
OF THE OMEGA BLOCK THAT WILL BE IN PLACE ACROSS THE EASTERN TWO
THIRDS OF THE NATION DURING THIS PERIOD. SINCE THE RIDGE OF THE
BLOCKING PATTERN IS EXPECTED TO STAY IN PLACE OVER NEW YORK STATE
AND PA...THE MOISTURE ASSOCIATED WITH THE MIDWEST CLOSED LOW SHOULD
STAY WELL TO OUR WEST. THE RIDGE WILL ALSO RESULT IN AN INCREASE IN
SUNSHINE. THIS SHOULD HELP DAYTIME TEMPERATURES HOLD IN THE LOWER
AND MID 70S.

&&

.AVIATION /19Z SUNDAY THROUGH FRIDAY/...
ALL TAF SITES WILL START OFF VFR AT 18Z. AN AREA OF RAIN SHOWERS
IS SLOWLY APPROACHING FROM THE SOUTHWEST...AND THIS WILL SLOWLY
MOVE INTO WESTERN NEW YORK THROUGH EARLY EVENING. THIS WILL BRING
A 2-3 HOUR PERIOD OF SHOWERS TO BUF/JHW/IAG/ROC...BUT WITH THE
SOUTHERLY DOWNSLOPE FLOW EXPECT CIGS AND VSBY TO REMAIN IN THE VFR
CATEGORY.

AFTER THIS EXPECT MORE HIT OR MISS SHOWERS. THESE WILL BE QUITE
SCATTERED IN NATURE...BUT COULD POTENTIALLY BRING BRIEF PERIOD OF MODERATE
TO HEAVY RAINFALL. AN ISOLATED THUNDERSTORM CANNOT BE RULED OUT. OTHERWISE...
EXPECT MAINLY VFR CONDITIONS TONIGHT...EXPECT FOR JHW WHERE THE
SOUTHERLY FLOW DOES NOT DOWNSLOPE LIKE THE OTHER TAF LOCATIONS.
THE RAIN SHOWERS WILL BE SUPPORTED BY A LOW LEVEL JET...WHICH WILL
PRODUCE SOME LOW LEVEL WIND SHEAR TONIGHT WITH 40-45 KNOT
SOUTHERLY WINDS AT 2K FEET.

FOR MONDAY...EXPECT THE MORNING TO MAINLY BE MVFR IN CIGS AS THE
FLOW BECOMES MORE SSW. SCATTERED SHOWERS WILL LINGER IN THE
MORNING...THEN TAPER OFF DURING THE AFTERNOON WITH GENERALLY
IMPROVING CONDITIONS.

OUTLOOK...
MONDAY NIGHT AND TUESDAY...MAINLY VFR. A CHANCE OF SHOWERS.
TUESDAY NIGHT THROUGH FRIDAY...VFR.

&&

.MARINE...
SOUTH TO SOUTHEAST WINDS WILL INCREASE THROUGH THIS EVENING AS THE
PRESSURE GRADIENT INCREASES ACROSS THE LOWER LAKES. WINDS MAY
APPROACH SMALL CRAFT ADVISORY CRITERIA FOR A TIME LATE TONIGHT AND
EARLY MONDAY...BUT OFFSHORE WINDS WILL KEEP THE GREATER WAVE
ACTION IN CANADIAN WATERS.

RELATIVELY LIGHT SOUTH TO SOUTHEAST WINDS ARE THEN EXPECTED TO
PERSIST FROM TUESDAY THROUGH THE END OF THE WEEK.

&&

.FIRE WEATHER...
DRIER AIR ALOFT HAS MIXED DOWN...RESULTING IN RELATIVE HUMIDITY
DOWN TO 25 PERCENT IN SOME LOCATIONS. WINDS WILL BE BREEZY THROUGH
MID TO LATE AFTERNOON OR SO...WITH A FEW GUSTS TO 25 MPH. RAIN FROM
A COUPLE DAYS AGO PROVIDED SOME WETTING...WHICH WILL HELP MITIGATE
IMPACTS OF THESE DRY CONDITIONS TO SOME DEGREE.

THESE CONDITIONS WILL BE SHORT-LIVED AS RAIN SHOWERS MOVE INTO
WESTERN PORTIONS OF THE SOUTHERN TIER. THESE WILL MOVE NORTHEAST
AND REACH ROCHESTER JUST BEFORE SUNSET.

&&

.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...NONE.

&&

$$

SYNOPSIS...APFFEL
NEAR TERM...APFFEL
SHORT TERM...WCH
LONG TERM...WCH
AVIATION...APFFEL
MARINE...APFFEL/WCH
FIRE WEATHER...APFFEL






AREA FORECAST DISCUSSION

NWS BUFFALO NY

 203 PM EDT SUN APR 28 2013

.SYNOPSIS...
HIGH PRESSURE WILL CONTINUE TO DRIFT OFF THE EAST COAST TODAY WITH
SOUTHERLY BREEZES PUSHING TEMPERATURES WELL ABOVE AVERAGE. A WEAK
AREA OF LOW PRESSURE WILL LIFT NORTHEAST OUT OF THE OHIO VALLEY AND
SPREAD SHOWERS INTO WESTERN NEW YORK LATE THIS AFTERNOON THEN ACROSS
THE REST OF THE AREA TONIGHT. OCCASIONAL SHOWERS WILL LAST THROUGH
MONDAY BEFORE DRY WEATHER RETURNS TUESDAY AND LASTS THROUGH NEXT
WEEKEND.

&&

.NEAR TERM /THROUGH TONIGHT/...
A CLOSED UPPER LEVEL LOW ACROSS INDIANA WILL SLOWLY MOVE TO THE
EAST THROUGH THIS EVENING. ASSOCIATED WITH THIS IS A LOW LEVEL JET
OF AROUND 40 KNOTS...WITH A STEADY AREA OF SHOWERS ACROSS
NORTHEASTERN OHIO AND WESTERN PENNSYLVANIA WHICH APPEARS TO BE
ASSOCIATED WITH THE LEADING EDGE OF THIS LOW LEVEL JET. THIS AREA
OF SHOWERS WILL CONTINUE TO GRADUALLY SPREAD NORTHEAST AND INTO
WESTERN NEW YORK DURING THE AFTERNOON HOURS. ITS PROGRESS MAY BE A
BIT SLOWER THAN PURE EXTRAPOLATION DUE TO DRYING FROM DOWNSLOPING.
THIS IS WELL CAPTURED BY THE HRRR AND MOST OTHER GUIDANCE...AND
THUS HAVE HIGH CONFIDENCE THAT THIS WILL BRING A 2-3 HOUR PERIOD
OF SHOWERS TO MOST LOCATIONS WEST OF ROCHESTER THROUGH EARLY
EVENING. AFTER THIS IT IS EXPECTED TO SHEAR AND DRY OUT LATE THIS EVENING.

UNTIL THIS REACHES US...IT WILL CONTINUE TO BE WARM AND A BIT
BREEZY. TEMPERATURES ARE IN THE LOWER TO MID 70S IN MANY
LOCATIONS...EXPECT ABOUT 10 DEGREES COOLER IN THE SOUTHERN TIER
WERE CLOUDS CAME IN EARLY. EXPECT THE ONSET OF SHOWERS TO CAUSE A
SIGNIFICANT AND QUICK DROP IN SURFACE TEMPERATURES WHEN IT STARTS.

AFTER THIS INITIAL ROUND OF SHOWERS MOVES THROUGH...PRECIPITATION
IS EXPECTED TO BE MUCH MORE HIT OR MISS. THIS CAN BE SEEN UPSTREAM
ON RADAR AS WELL...WITH SHOWERS BEHIND IT QUITE SCATTERED IN
NATURE. WITH THE UPPER TROF APPROACHING A SHOWER CANNOT BE RULED
OUT LATE TONIGHT...BUT EXPECT COVERAGE TO BE QUITE SPARSE.
ALSO...THERE WILL BE A LIMITED AMOUNT OF ELEVATED CAPE...WITH AN
ISOLATED THUNDERSTORM NOT COMPLETELY OUT OF THE QUESTION. FOR
NOW...WILL WAIT FOR UPSTREAM LIGHTNING STRIKES BEFORE ADDING THIS
INTO THE FORECAST GIVEN THE MARGINAL NATURE.

TEMPERATURES WILL DROP TONIGHT MAINLY BECAUSE OF EVAPORATIONAL
COOLING RATHER THAN RADIATIONAL COOLING DUE TO PERSISTENT WINDS
AND CLOUD COVER. LOWS WILL RANGE FROM THE UPPER 40S TO LOWER 50S.

&&

.SHORT TERM /MONDAY THROUGH WEDNESDAY NIGHT/...
SURFACE LOW PRESSURE MOVING NORTH FROM THE LOWER OHIO VALLEY WILL
CONTINUE TO WEAKEN ON MONDAY AS THE ASSOCIATED UPPER LEVEL TROUGH
WEAKENS AS IT TRACKS EAST ACROSS NEW YORK AND PA. AS THE UPPER LEVEL
TROUGH INTERACTS WITH LOW LEVEL MOISTURE THAT WILL BE TRANSPORTED
NORTH WITH A MODEST LOW LEVEL JET...ONGOING SHOWERS WILL MOVE EAST
ACROSS THE AREA. BECAUSE THE PRIMARY SOURCES LIFT WILL BE MOVING
EAST WHILE WEAKENING...WILL SHOW A DIMINISHING TREND IN THE PROB OF
PCPN AS THE DAY WEARS ON. THE SHOWERS WILL CONTINUE TO TAPER OFF
FROM WEST TO EAST MONDAY NIGHT AS THE WEAKENING TROUGH SLIDES OFF
THE NEW ENGLAND COAST. THIS SYSTEM DOES NOT APPEAR AS IF IT WILL BE
A BIG RAIN MAKER...PRODUCING ONLY ABOUT ONE OR TWO TENTHS OF AN INCH
OR RAINFALL.

CLOUDS AND PASSING SHOWERS WILL KEEP TEMPERATURES COOLER ON
MONDAY...WITH READINGS EXPECTED TO GENERALLY RANGE FROM THE UPPER
50S TO MID 60S.

HIGH PRESSURE AT THE SURFACE WILL REMAIN ANCHORED OFF THE NEW
ENGLAND COAST TUESDAY AND WEDNESDAY. AT THE SAME TIME...A RIDGE OF
HIGH PRESSURE ALOFT WILL STRENGTHEN ACROSS THE OHIO VALLEY AND
EASTERN GREAT LAKES IN RESPONSE TO A TROUGH THAT WILL BE DIGGING
INTO THE UPPER MIDWEST AND PLAINS STATES. THE HIGH SHOULD KEEP US
DRY THROUGH THIS PERIOD...ALTHOUGH WE MAY SEE A FAIR AMOUNT OF
CLOUDS AS A PERSISTENT SOUTH TO SOUTHEAST FLOW AT THE SURFACE TAPS
INTO ATLANTIC MOISTURE. HIGH TEMPERATURES ON TUESDAY WILL RANGE FROM
THE MID 60S TO LOWER 70S ON TUESDAY...WITH A SLIGHT MODERATION
EXPECTED ON WEDNESDAY. SEASONABLY MILD TEMPERATURES WILL BE THE RULE
TUESDAY NIGHT AND WEDNESDAY NIGHT.

&&

.LONG TERM /THURSDAY THROUGH SATURDAY/...
THE GFS AND ECMWF ARE NOW IN GOOD AGREEMENT REGARDING THE POSITION
OF THE OMEGA BLOCK THAT WILL BE IN PLACE ACROSS THE EASTERN TWO
THIRDS OF THE NATION DURING THIS PERIOD. SINCE THE RIDGE OF THE
BLOCKING PATTERN IS EXPECTED TO REMAIN IN PLACE OVER NEW YORK STATE AND
PA...THE MOISTURE THAT WILL BE ASSOCIATED WITH THE MIDWEST CLOSED
LOW SHOULD STAY WELL TO OUR WEST. THE RIDGE WILL ALSO RESULT IN AN
INCREASE IN SUNSHINE. THIS SHOULD HELP DAYTIME TEMPERATURES TO WARM
INTO THE LOWER AND MID 70S.

&&

.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
ALL TAF SITES WILL START OFF VFR AT 18Z. AN AREA OF RAIN SHOWERS
IS SLOWLY APPROACHING FROM THE SOUTHWEST...AND THIS WILL SLOWLY
MOVE INTO WESTERN NEW YORK THROUGH EARLY EVENING. THIS WILL BRING
A 2-3 HOUR PERIOD OF SHOWERS TO BUF/JHW/IAG/ROC...BUT WITH THE
SOUTHERLY DOWNSLOPE FLOW EXPECT CIGS AND VSBY TO REMAIN IN THE VFR
CATEGORY.

AFTER THIS EXPECT MORE HIT OR MISS SHOWERS. THESE WILL BE QUITE
SCATTERED IN NATURE...BUT COULD POTENTIALLY BRING BRIEF PERIOD OF MODERATE
TO HEAVY RAINFALL. AN ISOLATED THUNDERSTORM CANNOT BE RULED OUT. OTHERWISE...EXPECT
MAINLY VFR CONDITIONS TONIGHT...EXPECT FOR JHW WHERE THE SOUTHERLY
FLOW DOES NOT DOWNSLOPE LIKE THE OTHER TAF LOCATIONS. THE RAIN
SHOWERS WILL BE SUPPORTED BY A LOW LEVEL JET...WHICH WILL PRODUCE
SOME LOW LEVEL WIND SHEAR TONIGHT WITH 40-45 KNOT SOUTHERLY WINDS
AT 2K FEET.

FOR MONDAY...EXPECT THE MORNING TO MAINLY BE MVFR IN CIGS AS THE
FLOW BECOMES MORE SSW. SCATTERED SHOWERS WILL LINGER IN THE
MORNING...THEN TAPER OFF DURING THE AFTERNOON WITH GENERALLY
IMPROVING CONDITIONS.

OUTLOOK...
MONDAY NIGHT AND TUESDAY...MAINLY VFR. A CHANCE OF SHOWERS.
TUESDAY NIGHT THROUGH FRIDAY...VFR.

&&

.MARINE...
SOUTH TO SOUTHEAST WINDS WILL INCREASE THROUGH THIS EVENING AS THE
PRESSURE GRADIENT INCREASES ACROSS THE LOWER LAKES. WINDS MAY
APPROACH SMALL CRAFT ADVISORY CRITERIA FOR A TIME LATE TONIGHT AND
EARLY MONDAY...BUT OFFSHORE WINDS WILL KEEP THE GREATER WAVE
ACTION IN CANADIAN WATERS.

RELATIVELY LIGHT SOUTH TO SOUTHEAST WINDS ARE THEN EXPECTED TO
PERSIST FROM TUESDAY THROUGH THE END OF THE WEEK.

&&

.FIRE WEATHER...
DRIER AIR ALOFT HAS MIXED DOWN IN SOME LOCATIONS...RESULTING IN
RELATIVE HUMIDITY DOWN TO 25 PERCENT IN SOME LOCATIONS. WINDS WILL
BE BREEZY THROUGH MID-AFTERNOON OR SO...WITH A FEW GUSTS TO 25 MPH.
RAIN FROM A COUPLE DAYS AGO PROVIDED SOME WETTING...WHICH WILL
HELP MITIGATE IMPACTS OF THESE DRY CONDITIONS TO SOME DEGREE.

THESE CONDITIONS WILL BE SHORT-LIVED AS RAIN SHOWERS ARE
APPROACHING FROM THE SOUTHWEST. THESE WILL MOVE INTO WESTERN
PORTIONS OF THE SOUTHERN TIER THROUGH MID-AFTERNOON...AND REACH
ROCHESTER JUST BEFORE SUNSET.

&&

.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...NONE.

&&

$$

SYNOPSIS...HITCHCOCK
NEAR TERM...APFFEL/HITCHCOCK
SHORT TERM...TJP
LONG TERM...TJP
AVIATION...APFFEL
MARINE...APFFEL/HITCHCOCK
FIRE WEATHER...APFFEL





AREA FORECAST DISCUSSION

NWS BURLINGTON VT

 123 PM EDT SUN APR 28 2013

.SYNOPSIS...
HIGH PRESSURE WILL BE THE MAIN WEATHER FEATURE OVER THE REGION FOR
THE NEXT UPCOMING SEVERAL DAYS. THERE WILL BE A CHANCE FOR
PRECIPITATION ON MONDAY AND TUESDAY FOR NORTHERN NEW YORK...AS A
TROUGH OF LOW PRESSURE ATTEMPTS TO PUSH THROUGH THE AREA...OTHERWISE
DRY AND WARM CONDITIONS WILL PERSIST.

&&

.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
AS OF 1023 AM EDT SUNDAY...MINOR ADJUSTMENTS TO SFC DEWPOINTS TO
LOWER VALUES THROUGH THE AFTERNOON HOURS BEFORE RECOVERY LATER
THIS EVENING. RAP PROFILES SHOW DEPTH OF PBL TO AROUND 750 MB
TODAY SO THIS SHOULD MIX DOWN DRIER AIR ACCORDINGLY. OTW INHERITED
FORECAST IN GREAT SHAPE WITH SUNNY/MILD CONDITIONS EXPECTED. HAVE
A GREAT DAY.

PREVIOUS DISCUSSION...A NICE WARM DAY ON TAP FOR THE ENTIRE NORTH
COUNTRY AS HIGH PRESSURE REMAINS OVER THE NEW ENGLAND REGION. TO
OUR NORTH...CLDS FROM WK UPPER TROUGH PERSIST OVER QUEBEC...AND TO
OUR SOUTH LOW PRESSURE OVER THE LOWER TENNESSEE VALLEY. MDLS BEGIN
TO SHIFT RIDGE EASTWARD DURING THE COURSE OF THE DAY ALLOWING FOR
SOUTHERLY FLOW/WAA TO WORK INTO N NY. BUFKIT PROFILES DO SHOW VEIL
OF MID-LEVEL MOISTURE STREAMING NORTH ALONG THE WEST SIDE OF THE
SFC RIDGE BY THE AFTNOON...FUNNELED UP FROM SOUTHERN SYSTEM. WILL
GO FORTH AND BRING SOME CLD COVER FOR N NY DURING THIS TIME FRAME.
THE RESULT OF THESE EXPECTED CLDS WILL DAMPEN SUNSHINE AND THUS
HIGHS IN THAT AREA. OVERALL MID/UPPER 60S IN HIR ELEV AND UP TO
L70S IN VALLEY LOCALES WITH NO PRECIP EXPECTED TDY. GOING INTO
TNGT...SOUTHERLY FETCH PERSISTS THRU PERIOD ALLOWING FOR ABV
NORMAL LOWS RANGING FROM THE M30S FOR DACKS/NE VT TO THE 40S
ELSEWHERE. REMNANTS OF LOW TO OUR SOUTH WILL BE WORKING INTO THE
OHIO VALLEY OVERNGT KEEPING HIGHER CHANCE FOR CLDS OVER N NY AND
LESS FOR CVLY EASTWARD. SOME --RW WILL BEGIN TO DEVELOP OVER SLV
BY 12Z MONDAY AHEAD OF SFC LOW.

&&

.SHORT TERM /6 AM MONDAY MORNING THROUGH TUESDAY/...
AS OF 342 AM EDT SUNDAY...THE WX FOCUS FOR MONDAY AND TUESDAY
CONTINUES TO BE THE STRONG SFC RIDGE OVER CENTRAL AND EASTERN NEW
ENGLAND. THE REMNANTS OF SFC LOW FROM THE OHIO VALLEY WILL PUSH
INTO WESTERN NY DURING THE DAY. HAVE CONTINUED TREND OF LIGHT -RW
OVER N NY WITH NO EASTWARD PUSH PAST THE CVLY. PRECIP BEGINS TO
WANE GOING INTO THE EVENING/OVERNGT HRS MONDAY AS UPPER/SFC RIDGE
SHIFT BACK WESTWARD. SOME LINGERING --RW FOR WESTERN PORTIONS OF
SLV TUES MORNING ON THE WEST SIDE OF RIDGE...W/ STRONG SUBSIDENCE
FOR EASTERN DACKS/CVLY AND VT. HIGHEST TEMPS FOR MONDAY WILL OCCUR
CVLY EASTWARD AWAY FROM CLD COVER INFLUENCE OF OHIO VALLEY LOW.
OVERALL HIGHS WILL BE IN THE 60S FOR MONDAY AND MAINLY L70S FOR
TUESDAY W/ SOME 60S IN DACKS DUE TO CLD COVER.

&&

.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
AS OF 317 AM EDT SUNDAY...LITTLE CHANGE IN 00Z NWP GUIDANCE SUITE WITH
RESPECT TO QUIET EXTENDED FCST. PROMINENT MID-TROPOSPHERE OMEGA
BLOCK DEVELOPS ACROSS THE ERN GREAT LAKES INTO SERN ONTARIO/WRN
QUEBEC BRINGING TRANQUIL WEATHER TO THE NORTH COUNTRY THRU
SATURDAY. NO PRECIPITATION FCST. WITH SUBSIDENCE AND MOSTLY CLEAR
SKIES...MODERATELY LARGE DIURNAL TEMPERATURE RANGES ARE FORECAST
WITH HIGHS MAINLY IN THE LOWER 70S AND LOWS IN THE LOW-MID 40S. EXPECT
SLIGHTLY COOLER DAYTIME HIGHS ALONG THE LAKE CHAMPLAIN SHORELINE...PER
WATER TEMP ONLY 40F. FOR OVERNIGHT TEMPS...A FEW MID-UPR 30S
ANTICIPATED IN THE NORMALLY COLDER VALLEYS OF FAR NERN VT AND
WITHIN THE NRN ADIRONDACK REGION.

&&

.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
THROUGH 18Z MONDAY...VFR CONDITIONS WL PREVAIL AT ALL TAF SITES
THRU 18Z MONDAY...AS SFC HIGH PRES CONTS ACRS OUR FA.
HOWEVER...MID/UPPER LVL MOISTURE WL PRODUCE AN INCREASE IN HIGH
CLOUDS FROM SW TO NE ACRS OUR TAF SITES TONIGHT. A FEW LIGHT
SHOWERS WL BE POSSIBLE BY 12Z MONDAY NEAR KMSS...BUT GIVEN VERY
DRY LLVLS EXPECT MOSTLY VIRGA TO FALL...AND WL JUST MENTION VCSH
ATTM...WITH CIGS BKN AT 5000 FT. SOUTH TO SOUTHWEST WIND AT 5 TO
10 KNTS WL CONT THIS AFTN AND BECM TRRN DRIVEN OVERNIGHT. ON
MONDAY...SOUNDINGS SHOW THE LLVL WIND FIELD INCREASE WITH SFC
GUSTS BTWN 15 AND 20 KNTS POSSIBLE AFT 12Z.

OUTLOOK 18Z MONDAY THROUGH FRIDAY...
18Z MONDAY-12Z TUESDAY...BRIEF INTERVALS OF MVFR POSSIBLE WITH A
FEW RAIN SHOWERS...ESPECIALLY MSS AND SLK.

18Z TUESDAY-18Z FRIDAY...SFC HIGH PRES AND VFR WITH LIGHT WINDS WL
PREVAIL AT ALL TAF SITES.

&&

.BTV WATCHES/WARNINGS/ADVISORIES...
VT...NONE.
NY...NONE.

&&

$$
SYNOPSIS...JN
NEAR TERM...JMG/JN
SHORT TERM...JN
LONG TERM...BANACOS
AVIATION...TABER










AREA FORECAST DISCUSSION

NWS BURLINGTON VT

 1023 AM EDT SUN APR 28 2013

.SYNOPSIS...
HIGH PRESSURE WILL BE THE MAIN WEATHER FEATURE OVER THE REGION FOR
THE NEXT UPCOMING SEVERAL DAYS. THERE WILL BE A CHANCE FOR
PRECIPITATION ON MONDAY AND TUESDAY FOR NORTHERN NEW YORK...AS A
TROUGH OF LOW PRESSURE ATTEMPTS TO PUSH THROUGH THE AREA...OTHERWISE
DRY AND WARM CONDITIONS WILL PERSIST.

&&

.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
AS OF 1023 AM EDT SUNDAY...MINOR ADJUSTMENTS TO SFC DEWPOINTS TO
LOWER VALUES THROUGH THE AFTERNOON HOURS BEFORE RECOVERY LATER
THIS EVENING. RAP PROFILES SHOW DEPTH OF PBL TO AROUND 750 MB
TODAY SO THIS SHOULD MIX DOWN DRIER AIR ACCORDINGLY. OTW INHERITED
FORECAST IN GREAT SHAPE WITH SUNNY/MILD CONDITIONS EXPECTED. HAVE
A GREAT DAY.

PREVIOUS DISCUSSION...A NICE WARM DAY ON TAP FOR THE ENTIRE NORTH
COUNTRY AS HIGH PRESSURE REMAINS OVER THE NEW ENGLAND REGION. TO
OUR NORTH...CLDS FROM WK UPPER TROUGH PERSIST OVER QUEBEC...AND TO
OUR SOUTH LOW PRESSURE OVER THE LOWER TENNESSEE VALLEY. MDLS BEGIN
TO SHIFT RIDGE EASTWARD DURING THE COURSE OF THE DAY ALLOWING FOR
SOUTHERLY FLOW/WAA TO WORK INTO N NY. BUFKIT PROFILES DO SHOW VEIL
OF MID-LEVEL MOISTURE STREAMING NORTH ALONG THE WEST SIDE OF THE
SFC RIDGE BY THE AFTNOON...FUNNELED UP FROM SOUTHERN SYSTEM. WILL
GO FORTH AND BRING SOME CLD COVER FOR N NY DURING THIS TIME FRAME.
THE RESULT OF THESE EXPECTED CLDS WILL DAMPEN SUNSHINE AND THUS
HIGHS IN THAT AREA. OVERALL MID/UPPER 60S IN HIR ELEV AND UP TO
L70S IN VALLEY LOCALES WITH NO PRECIP EXPECTED TDY. GOING INTO
TNGT...SOUTHERLY FETCH PERSISTS THRU PERIOD ALLOWING FOR ABV
NORMAL LOWS RANGING FROM THE M30S FOR DACKS/NE VT TO THE 40S
ELSEWHERE. REMNANTS OF LOW TO OUR SOUTH WILL BE WORKING INTO THE
OHIO VALLEY OVERNGT KEEPING HIGHER CHANCE FOR CLDS OVER N NY AND
LESS FOR CVLY EASTWARD. SOME --RW WILL BEGIN TO DEVELOP OVER SLV
BY 12Z MONDAY AHEAD OF SFC LOW.

&&

.SHORT TERM /6 AM MONDAY MORNING THROUGH TUESDAY/...
AS OF 342 AM EDT SUNDAY...THE WX FOCUS FOR MONDAY AND TUESDAY
CONTINUES TO BE THE STRONG SFC RIDGE OVER CENTRAL AND EASTERN NEW
ENGLAND. THE REMNANTS OF SFC LOW FROM THE OHIO VALLEY WILL PUSH
INTO WESTERN NY DURING THE DAY. HAVE CONTINUED TREND OF LIGHT -RW
OVER N NY WITH NO EASTWARD PUSH PAST THE CVLY. PRECIP BEGINS TO
WANE GOING INTO THE EVENING/OVERNGT HRS MONDAY AS UPPER/SFC RIDGE
SHIFT BACK WESTWARD. SOME LINGERING --RW FOR WESTERN PORTIONS OF
SLV TUES MORNING ON THE WEST SIDE OF RIDGE...W/ STRONG SUBSIDENCE
FOR EASTERN DACKS/CVLY AND VT. HIGHEST TEMPS FOR MONDAY WILL OCCUR
CVLY EASTWARD AWAY FROM CLD COVER INFLUENCE OF OHIO VALLEY LOW.
OVERALL HIGHS WILL BE IN THE 60S FOR MONDAY AND MAINLY L70S FOR
TUESDAY W/ SOME 60S IN DACKS DUE TO CLD COVER.

&&

.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
AS OF 317 AM EDT SUNDAY...LITTLE CHANGE IN 00Z NWP GUIDANCE SUITE WITH
RESPECT TO QUIET EXTENDED FCST. PROMINENT MID-TROPOSPHERE OMEGA
BLOCK DEVELOPS ACROSS THE ERN GREAT LAKES INTO SERN ONTARIO/WRN
QUEBEC BRINGING TRANQUIL WEATHER TO THE NORTH COUNTRY THRU
SATURDAY. NO PRECIPITATION FCST. WITH SUBSIDENCE AND MOSTLY CLEAR
SKIES...MODERATELY LARGE DIURNAL TEMPERATURE RANGES ARE FORECAST
WITH HIGHS MAINLY IN THE LOWER 70S AND LOWS IN THE LOW-MID 40S. EXPECT
SLIGHTLY COOLER DAYTIME HIGHS ALONG THE LAKE CHAMPLAIN SHORELINE...PER
WATER TEMP ONLY 40F. FOR OVERNIGHT TEMPS...A FEW MID-UPR 30S
ANTICIPATED IN THE NORMALLY COLDER VALLEYS OF FAR NERN VT AND
WITHIN THE NRN ADIRONDACK REGION.

&&

.AVIATION /15Z SUNDAY THROUGH THURSDAY/...
THROUGH 12Z MONDAY...VFR. SKC-SCT250 THRU THE DAYLIGHT HRS. HIGH
PRESSURE BRINGS LIGHT AND VARIABLE WINDS EARLY THIS MORNING. AS
RIDGE AXIS SLIDES INTO THE GULF OF MAINE THIS AFTERNOON...WINDS
BECG SE-S AT 5-7 KTS. SOME INCREASE IN MID-LEVEL CLOUDS (10-15
KFT) OVERNIGHT AS MID-LEVEL TROUGH SHIFTS NEWD INTO THE UPR OH
RIVER VALLEY. ANY SHOWER ACTIVITY IS EXPECTED TO REMAIN SOUTH AND
WEST OF THE REGION THRU 12Z MONDAY.

OUTLOOK 12Z MONDAY THROUGH THURSDAY...
12Z MONDAY-12Z TUESDAY...BRIEF INTERVALS OF MVFR POSSIBLE WITH A
FEW RAIN SHOWERS.

12Z TUESDAY-00Z FRIDAY...VFR WITH LIGHT WINDS.

&&

.BTV WATCHES/WARNINGS/ADVISORIES...
VT...NONE.
NY...NONE.

&&

$$
SYNOPSIS...JN
NEAR TERM...JMG/JN
SHORT TERM...JN
LONG TERM...BANACOS
AVIATION...BANACOS







AREA FORECAST DISCUSSION

NWS WILMINGTON NC

 346 PM EDT SUN APR 28 2013

.SYNOPSIS...
HIGH PRESSURE OFF THE NEW ENGLAND COASTLINE WILL LOSE ITS GRIP ON
OUR WEATHER AS DISORGANIZED LOW PRESSURE DEVELOPS ACROSS THE
SOUTHEASTERN UNITED STATES. THIS LOW WILL BRING INCREASING CHANCE
OF SHOWERS TONIGHT THROUGH MONDAY WITH WIDESPREAD SHOWERS AND
ISOLATED THUNDERSTORMS ON MONDAY. THE LOW WILL PUSH OFFSHORE
TUESDAY BUT MAY LINGER AS HIGH PRESSURE BUILDS DOWN FROM THE
NORTH. A TROUGH OF LOW PRESSURE WILL BRING UNSETTLED WEATHER
WEDNESDAY THROUGH FRIDAY AND MAY LINGER INTO THE WEEKEND.

&&

.NEAR TERM /THROUGH TONIGHT/...
AS OF 3 PM SUNDAY...TIMING OF PCPN AND EVEN CLOUDINESS
OVERSPREADING THE FORECAST AREA CONTINUES TO REMAIN THE MAIN
ISSUES FOR THE NEAR TERM PERIOD. THE NORTH TO SOUTH MID-LEVEL
RIDGE AXIS REMAINS THE PROBLEM CHILD AS IT HAS BECOME MUCH SLOWER
IN MOVING FURTHER EAST OF THE FORECAST AREA TODAY. IN TURN THIS
HAS ALLOWED A PERSISTENT AND DRIER LOW LEVEL EASTERLY FLOW TO
AFFECT MAINLY THE EASTERN PORTIONS OF THE FA RESULTING IN
BASICALLY PCPN UNABLE TO MAKE ANY PROGRESS EASTWARD TO THE COAST.
MODELS ARE FINALLY IN UNISON...PUSHING THE UPPER RIDGE AXIS OFF
THE CAROLINA COASTS THIS AFTERNOON AND EVENING...AND FINALLY
ALLOWING THE ATM TO MOISTEN UP. LOOK FOR SLOWLY INCREASING POPS
THIS AFTERNOON...REACHING CATEGORICAL AFTER MIDNIGHT ACROSS ALL
LOCATIONS. HAVE INCLUDED ISOLATED CONVECTION OVERNIGHT...DUE TO A
SLOWLY DESTABILIZING ATM AS AN UPPER VORT MOVES TOWARD THE
FA...AND IN ADDITION A WEAK WSW-ENE ORIENTED SFC TROF TO MANIFEST
ITSELF ACROSS THE FA. WILL ONLY INCLUDE ISOLATED AT THIS POINT.
CLOUDS...PCPN...AND AN ONSHORE FLOW WILL LIMIT DECREASING TEMPS
OVERNIGHT. HAVE BASICALLY GONE WITH A MILD NIGHT ADVERTISING
NEARLY WIDESPREAD LOW 60S FOR MINS...WITH A FEW POCKETS OF UPPER
50S.

&&

.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AS OF 3 PM SUNDAY...HIGH PRESSURE FROM THE SURFACE UP THROUGH
THE MID TO UPPER LEVELS WILL SHIFT EAST AS H5 SHORTWAVE MOVES
CLOSER TOWARD THE LOCAL AREA. THIS WILL PRODUCE A DEEP RETURN FLOW
OF WARM MOIST AIR UP THROUGH THE SOUTHEAST THROUGH MONDAY. DECENT
MID TO UPPER LEVEL DYNAMICS WILL COME INTO PLAY ON MONDAY COMBINED
WITH HEATING AND LOCAL EFFECTS SUCH AS SEA BREEZE CONVERGENCE AND
ANY OTHER LOCAL BOUNDARIES THAT DEVELOP. SHOULD TAP INTO BOTH GULF
AND ATLANTIC MOISTURE AS LLJ INCREASES UP AROUND 30 TO 35 KTS.
DEWPOINT TEMPS WILL REACH AROUND 60 WITH PCP WATER VALUES REACHING
UP AROUND 1.5 INCHES. SIGNIFICANT CLOUD COVER ON MONDAY MAY LIMIT
BEST THUNDERSTORM POTENTIAL...BUT SHOULD SEE WIDESPREAD SHOWERS
AND ISOLATED TSTMS THROUGH THE DAY.

MID TO UPPER TROUGH AXIS WILL MOVE OFF SHORE OVERNIGHT MONDAY INTO
TUES WITH INCREASING SUBSIDENCE ON BACK END. HIGH PRESSURE WILL
BUILD DOWN FROM THE NORTH WHILE LOW PRESSURE OVER THE GULF
MAINTAINS MORE UNSETTLED WEATHER TO THE SOUTH AND COASTAL
TROUGH/WEAK LOW EXTENDS UP THROUGH THE LOCAL WATERS TO THE EAST.
OVERALL EXPECT A FAIR AMOUNT OF LINGERING MOISTURE. NAM PUSHES THE
COASTAL TROUGH BACK INLAND WHILE THE GFS SHOWS HIGH PRESSURE
BUILDING DOWN WITH A COOLER NORTHERLY FLOW DEVELOPING. EITHER
WAY...EXPECT SUNSHINE ON TUESDAY WILL LEAD TO DAYTIME HEATING AND
GREATER INSTABILITY. THEREFORE WOULD EXPECT THIS TO HELP PRODUCE
MORE CU BUILDUP AND POSSIBLE SHOWERS ON TUES.

WAA WILL LEAD TO TEMPS REACHING INTO THE 70S ON MONDAY BUT THIS
WILL BE HAMPERED BY CLOUDS AND SHOWER ACTIVITY AND THEREFORE DO
NOT EXPECT MUCH MORE THAN LOWER 70S. TUES WILL HAVE GREATER AMOUNT
OF SUNSHINE LEADING TO TEMPS IN THE MID 70S MOST PLACES. SOME
UNCERTAINTY EXISTS AS TO HOW FAR HIGH PRESSURE WILL BUILD IN
POSSIBLY PRODUCING A COOLER NORTHERLY FLOW. OVERNIGHT LOWS WILL BE
CLOSE TO 60 BOTH NIGHTS WITH CLOUDS AND INCREASED MOISTURE
PRESENT.

&&

.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
AS OF 3 PM SUNDAY...COMPLICATED AND HIGHLY AMPLIFIED PATTERN TO
WREAK HAVOC ON THE EXTENDED FORECAST. WHILE BASIC SYNOPTIC REGIME
IS AGREED UPON BY MOST GUIDANCE...MINOR TEMPORAL AND SPATIAL
DIFFERENCES LEAD TO SIGNIFICANT VARIATIONS IN THE SENSIBLE
WEATHER.

SOME AGREEMENT INITIALLY IN THAT WEAK LOW/TROUGH WILL ENHANCE SOME
ISENTROPIC LIFT ABOVE A SURFACE HIGH RIDGING DOWN THE COAST. THIS
WILL SUPPORT SOME SHOWERS WED/THU...BUT OVERALL COVERAGE AND
INTENSITY WILL BE LIGHT. HAVE DROPPED POP FROM INHERITED TO SCHC THU
THANKS TO THE DRIER SOLUTION NOW SUPPORTED BY THE FAVORED ECMWF.
WILL NOT GO DRY AS SOME LOW LEVEL MOISTURE REMAINS IN FORECAST
PROFILES...BUT THURSDAY MAY TURN OUT TO JUST BE CLOUDY. TEMPS
WED-THU WILL BE SLIGHTLY BELOW CLIMO FOR HIGHS AND SLIGHTLY ABOVE
FOR LOWS.

PATTERN BECOMES MORE COMPLEX THEREAFTER AS OMEGA BLOCK DEVELOPS
ACROSS THE EXTREME EASTERN CONUS/WESTERN ATLANTIC BETWEEN DEEP 5H
CUTOFF LOWS ON EITHER SIDE. EPD FROM WPC THIS MORNING SAYS IT BEST,
`THE ATMOSPHERE WILL HIT THE BRAKES HARD AND TEMPORARILY PAUSE THE
UPPER LEVEL FLOW.` THIS OCCURS AS FLOW BECOMES BLOCKED (HENCE THE
TERM) FORCING SYSTEMS TO STALL OR EVEN RETROGRADE AS IS THE PROGGED
CASE FOR THE MIDWEST SYSTEM. CURRENT ECMWF IS A REASONABLE
COMPROMISE BETWEEN THE GFS/CMC SOLUTIONS...AND WILL BE RELIED UPON
HEAVILY FOR THIS PACKAGE. WHILE MUCH UNCERTAINTY STILL EXISTS IN THE
EXACT PLACEMENT OF THESE FEATURES...TREND HAS BEEN FOR A SLIGHTLY
STRONGER RIDGE...AND HENCE A MORE WESTWARD BLOCK OF THE
UPPER/SURFACE SYSTEMS. THIS COULD VERY WELL MEAN A WARM AND DRY
WEEKEND AS COLD FRONT GETS HUNG UP WELL WEST OF THE REGION...ALBEIT
WITH STILL NE COOLING SURFACE WIND. FOR NOW...WILL CONTINUE WITH
SCHC FOR THE WKND WITH SLIGHTLY BELOW NORMAL TEMPS...BUT MAY HAVE TO
TREND WARMER AND DRIER AS THE FORECAST EVOLVES.

&&

.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
AS OF 18Z...LIGHT RADAR RETURNS OVER THE INLAND PORTIONS OF THE
FORECAST AREA HAS PRODUCED BRIEF PERIODS OF -RA AT KFLO THIS
MORNING AND LBT THIS AFTERNOON. CURRENTLY VFR AT ALL TERMS WITH
MAINLY MID-LEVEL CIGS AROUND 10KFT AND SCT LOWER CLOUDS AROUND 5K
FT ESPECIALLY INLAND WHERE VIRGA IS LIKELY OCCURRING. EXPECT BRIEF
PERIODS OF -RA TO CONTINUE AT KFLO/KLBT THIS AFTERNOON. ALONG THE
COAST...THE DRIER LOW LEVELS COMPARED TO INLAND...WILL PREVENT
PCPN FROM REACHING THE SFC UNTIL AFTER 00Z. RAIN CHANCES INCREASE
TONIGHT AS THE SHORTWAVE TO OUR WEST MOVES CLOSER TO THE
CAROLINAS. HRRR INDICATES SHOWER ACTIVITY AND COVERAGE WILL
INCREASE OVERNIGHT INTO MON. MVFR CIGS...WITH IFR LATE...CIGS
WILL LIKELY DEVELOP AS THE COLUMN SATURATES AND RAINFALL
PERSISTS... BEGINNING AT KFLO/KLBT. EXPECT LIGHT STRATIFORM RAINS
THIS AFTERNOON THROUGH THE OVERNITE...WITH POCKETS OF MODERATE RW.
CONVECTIVE TYPE PCPN WILL BECOME MORE DOMINANT AFTER DAYBREAK MON
AS THE ATM DESTABILIZES.

EXTENDED OUTLOOK...SHOWERS/ISO TSTMS LIKELY WITH MVFR/IFR POSSIBLE
THROUGH MONDAY NIGHT. CHANCE OF SHOWERS TUESDAY AND WEDNESDAY.
SLIGHT RAIN CHANCES LINGER FOR MUCH OF THE EXTENDED PERIOD.

&&

.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 3 PM SUNDAY...THE NOSE OF SFC HIGH PRESSURE HAS FINALLY
BEGUN TO GET SHUNTED EASTWARD...AND SHOULD BE OFF THE CAROLINA
COASTS EARLY THIS EVENING. THIS WILL ALLOW A VEERING WIND TO
OCCUR...WITH AN ENE-E WIND LATE THIS AFTERNOON...BECOMING ESE-SE
THIS EVENING...AND FURTHER VEERING TO MORE OF A SOUTHERLY
DIRECTION DURING THE PRE-DAWN HRS OF MON. SOMEWHAT RELAXED SFC PG
PROGGED THIS AFTERNOON AND EVENING...AND FINALLY TIGHTENS-SOME
AFTER MIDNIGHT. WIND SPEEDS OF 8-12 KT EARLY THIS EVENING...WILL
INCREASE TO NEARLY A SOLID 15 KT WITH GUSTS AOA 20 KT.

A DECENT FETCH WILL EXIST ALLOWING FOR AN EASTERLY GROUND SWELL AT 2
TO 3 FT EXHIBITING 12-15 SECOND PERIODS TO AFFECT THE LOCAL WATERS.
COMBINED WITH A SLOWLY INCREASING LOCALLY PRODUCED WIND DRIVEN
WAVES...SIGNIFICANT SEAS WILL RANGE BETWEEN 3 TO 4 FT...WITH 5
FOOTERS ALONG THE OUTER WATERS ESPECIALLY OFF CAPE FEAR TO SURF
CITY. WILL BECOME BORDERLINE SCEC CONDITIONS AFTER MIDNIGHT.
STRATIFORM PCPN WILL WEAKEN AND BREAK-UP AS IT MOVES OFF THE
MAINLAND LATE THIS AFTERNOON. HOWEVER...TONIGHT THE PCPN MOVING OFF
THE MAINLAND WILL HAVE BETTER DYNAMICS ALOFT TO WORK WITH AND A
MOISTENING ATM PROFILE...AND THUS WILL NOT DISSIPATE.

SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AS OF 3 PM SUNDAY...HIGH PRESSURE SHIFTS FARTHER OFF THE COAST
WITH AN INCREASING RETURN FLOW SETTING UP THROUGH MONDAY. EXPECT
SOUTHERLY WINDS UP AROUND 15 KTS THROUGH MONDAY AFTERNOON AS
GRADIENT TIGHTENS. MID TO UPPER TROUGH WILL MOVE THROUGH PRODUCING
FAIRLY WIDESPREAD SHWRS AND ISOLATED THUNDERSTORMS WHICH MAY HELP
TO INCREASE WINDS AND CHURN UP SEAS. OVERALL EXPECT SEAS TO
INCREASE TO 3 TO 5 FT THROUGH MONDAY WITH A STRONG SOUTHERLY PUSH.
SEAS WILL SUBSIDE THROUGH TUESDAY AS GRADIENT RELAXES AND WINDS
DIMINISH TO 10 KTS OR LESS. SEAS WILL DROP TO 2 TO 4 FT BY TUESDAY.

LONG TERM /WEDNESDAY THROUGH FRIDAY/...
AS OF 300 PM SUNDAY...HIGH PRESSURE RIDGING DOWN THE COAST AND A
TROUGH OF LOW PRESSURE STRENGTHENING OFFSHORE WILL CREATE A
GRADUALLY TIGHTENING PRESSURE GRADIENT...AND INCREASING NE WINDS
INTO FRIDAY. THE STRONGEST WINDS WILL BE THURSDAY AFTN INTO FRIDAY
MORNING...WHEN 20-25 KT NE ARE EXPECTED. OTHERWISE WINDS WILL BE
10-15 KTS...VEERING SLIGHTLY TO THE EAST FRIDAY AS GRADIENT RELAXES.
ALTHOUGH A DECENT 10-13 SEC EAST SWELL WILL GRADUALLY DECAY THROUGH
THE PERIOD...WAVES WILL BE PREDOMINANTLY WIND-DRIVEN. SEAS OF 2-4 FT
EARLY WEDNESDAY WILL RISE TO 4-7 FT THURSDAY AND EARLY
FRIDAY...BEFORE FALLING AGAIN FRIDAY. A SMALL CRAFT ADVISORY WILL
LIKELY BE NEEDED ALL OF THURSDAY AND MUCH OF FRIDAY.

&&

.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.

&&

$$

NEAR TERM...DCH
SHORT TERM...RGZ
LONG TERM...III
AVIATION...DCH/BJR







AREA FORECAST DISCUSSION

NWS WILMINGTON NC

 208 PM EDT SUN APR 28 2013

.SYNOPSIS...
A SERIES OF DISORGANIZED LOW PRESSURE AREAS WILL BRING AN INCREASED
CHANCE OF SHOWERS AND THUNDERSTORMS THROUGH MONDAY. A DRYING TREND
IS EXPECTED DURING THE MIDDLE OF THE WEEK. A BACKDOOR COLD FRONT
WILL DROP SOUTH THROUGH THE AREA WEDNESDAY...AND A SECOND FRONT WILL
APPROACH FROM THE WEST LATE NEXT WEEKEND.

&&

.NEAR TERM /THROUGH TONIGHT/...
AS OF 1000 AM SUNDAY...TIMING OF PCPN AND CLOUDINESS OVERSPREADING
THE FORECAST AREA THROUGH TONIGHT ARE THE MAIN PARAMETERS NEEDING
UPDATES. EXTRAPOLATED USING THE LATEST TRENDS/LOOPS OF THE 88D
RADAR MOSAIC AND VISIBLE SATELLITE IMAGERY...AND IN ADDITION THE
LATEST HOURLY HRRR UPDATES. STRATIFORM LIGHT RAIN WILL CONTINUE AS
THE MAIN PCPN TYPE...WITH ISOLATED THUNDER POSSIBLE THIS
AFTERNOON THROUGH TONIGHT ASSOCIATED WITH WEAK DYNAMICS FROM THE
PASSAGE OF THOSE WEAK MID LEVEL VORT LOBES. HAVE ALSO UPDATED QPF
FIELDS TO ACCOUNT FOR THE PCPN TIMING...BUT IN GENERAL HAVE KEPT
THE 24 HR AMOUNTS IN TUNE TO THE PREVIOUS FCST.

PREVIOUS DISCUSSION....................................
AS OF 630 AM SUNDAY...RADAR SHOWS A BATCH OF MAINLY LIGHT RAIN
MOVING THROUGH THE SC SAND HILLS AND APPROACHING FLORENCE. MEASURABLE
RAIN IS REACHING THE GROUND AS SHOWN BY THE .02 INCH HOURLY AMOUNT
JUST MEASURED AT THE KCDN AWOS. MUCH LIKE WE SAW YESTERDAY THIS RAIN
SHOULD LOSE ITS PUNCH AS IT MOVES EASTWARD INTO DRIER LOW LEVELS
EAST OF THE MID AND UPPER LEVEL RIDGE AXIS. THE LATEST FEW HRRR RUNS
SUGGEST WE`LL SEE A BREAK IN PRECIPITATION EVEN ACROSS THE PEE DEE
REGION FROM NOON THROUGH MID AFTERNOON...WITH A MUCH MORE
SUBSTANTIAL BAND OF SHOWERS PUSHING TOWARD THE I-95 CORRIDOR BY
EARLY EVENING. NO CHANGES HAVE BEEN MADE TO TEMPERATURE FORECASTS...
BUT IT WILL BE INTERESTING TO SEE HOW MUCH OPAQUE CLOUD COVER HANGS
AROUND BEYOND NOON IF THERE IS INDEED A SIZABLE BREAK IN
PRECIPITATION. THIS COULD HAVE IMPACTS ON HIGH TEMPERATURE FORECASTS
TOO. PREVIOUS DISCUSSION FROM 300 AM FOLLOWS...

SURFACE HIGH PRESSURE STALLED OFF THE NEW ENGLAND COASTLINE
CONTINUES TO FEED HEAVILY MODIFIED BUT STILL QUITE DRY ARCTIC AIR
SOUTHWARD ACROSS THE WESTERN ATLANTIC. THIS FLOW OF AIR IS THEN
ADVECTING INTO THE EASTERN CAROLINAS WHERE IT HAS EATEN UP AT LEAST
THREE EASTWARD-MOVING WAVES OF RAIN OVER THE 24 HOURS. YET ANOTHER
BATCH OF RAIN CURRENTLY ENTERING WESTERN SOUTH CAROLINA WILL LIKELY
FEEL THE EFFECTS OF THIS DRY AIR LATER THIS MORNING. MY FORECAST HAS
RAIN CHANCES HIGHEST WEST OF I-95...WITH VERY LITTLE PRECIPITATION
POTENTIAL DOWN AT THE COAST.

THE UPPER LEVEL PATTERN SHOWS A LOW ACROSS ILLINOIS WITH A SOUTHERN
STREAM RIDGE OVER THE CAROLINAS. WEAK SOUTHERN STREAM DISTURBANCES
ALOFT ARE DAMPING OUT AS THEY MOVE THROUGH THIS RIDGE POSITION IN
THE JET...BUT PLENTY OF GULF MOISTURE BEING LIFTED INTO THE MIDDLE
AND UPPER LEVELS OF THE ATMOSPHERE IS SUPPORTING A BROAD ZONE OF
CLOUDS WITH AREAS OF RAIN ACROSS GEORGIA AND THE WESTERN CAROLINAS.
THE UPPER RIDGE IS EXPECTED TO PUSH OFFSHORE TONIGHT...ALLOWING THE
INCOMING DISTURBANCES AND MOISTURE STREAM TO REACH THE EASTERN
CAROLINAS MORE INTACT. ALSO OF IMPORTANCE ARE TWO JET STREAKS WHICH
TONIGHT MOVE INTO FAVORABLE POSITIONS (FLORIDA PANHANDLE AND
CHESAPEAKE BAY REGION) FOR BOTH TO PROVIDE ADDITIONAL SYNOPTIC LIFT
FOR PRECIPITATION LOCALLY. FOR THIS REASON I HAVE POPS FORECAST AT
100 PERCENT ACROSS THE I-95 CORRIDOR THIS AFTERNOON AND TONIGHT...
WITH RAIN CHANCES FINALLY INCREASING TO 60-70 PERCENT AT THE COAST
LATE TONIGHT.

CLOUDS AND ONSHORE WINDS WILL HELP CONSTRAIN DIURNAL RANGES...WITH
DAYTIME HIGHS 68-73 AND LOWS TONIGHT 58-63.

&&

.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AS OF 3 AM SUNDAY...MID LEVEL RIDGE TO THE EAST AND TROUGHING TO THE
WEST SETS UP DEEP SOUTHWEST FLOW ALOFT WHICH PUSHES GULF MOISTURE
INTO THE REGION MON/MON NIGHT. MEANWHILE AT THE SURFACE HIGH
PRESSURE OFF THE EASTERN US COAST WILL ADVECT LOW LEVEL ATLANTIC
MOISTURE INTO REGION. DEEP MOISTURE...DIVERGENT FLOW ALOFT...WEAK
COASTAL TROUGH(WHICH MAY OR MAY NOT MOVE ONSHORE)...AND DIURNAL
INSTABILITY SHOULD PRODUCE WIDESPREAD SHOWERS WITH ISOLATED
THUNDERSTORMS. BASED ON FORECAST SOUNDINGS DO NOT THINK UPDRAFTS
WILL BE ALL THAT STRONG SO DO NOT ANTICIPATE MUCH IN THE WAY OF
LIGHTNING...BUT INLAND AREAS WOULD BE MORE FAVORED ESPECIALLY IN THE
AFTERNOON. DO NOT ANTICIPATE ANY SEVERE WEATHER GIVEN LOW CAPE
VALUES...LACK OF ANY JETTING...AND WEAK LAPSE RATES. PRECIPITABLE
WATER VALUES WILL BE ABOUT 2 STANDARD DEVIATIONS ABOVE NORMAL SO
HEAVY RAIN COULD BE AN ISSUE.

MID LEVEL SHORTWAVE TROUGH MOVES OFF THE EAST COAST EARLY TUE.
ALTHOUGH THERE REMAINS SOME DISCREPANCY BETWEEN THE GUIDANCE
AGREEMENT ON TUE IS MUCH BETTER THAN IS WAS 24 HOURS AGO. SUBSIDENCE
BEHIND THE EXITING SHORTWAVE AND FROM WEAK MID LEVEL RIDGE BUILDING
IN FROM THE NORTHWEST HELPS DRY THE AREA FOR TUE/TUE NIGHT. LOW
LEVEL MOISTURE COMBINED WITH DIURNAL INSTABILITY COULD GENERATE A
FEW SHOWERS DURING THE AFTERNOON AND EVENING HOURS BUT COVERAGE WILL
BE CONSIDERABLY LESS THAN MON. CLOUDS AND RAIN ON MON WILL KEEP
HIGHS BELOW CLIMO BUT CLEARING EXPECTED ON TUE WILL LEAD TO HIGHS
NEAR CLIMO. LOWS WILL REMAIN ABOVE CLIMO THROUGH THE PERIOD.

&&

.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
AS OF 3 AM SUNDAY...STILL A LOT OF HAND WRINGING IN THE EXTENDED.
GFS/ECMWF HAVE COME INTO MUCH BETTER AGREEMENT OVER THE LAST DAY OR
SO BUT PITFALLS ABOUND IN THE LONG TERM. BOTH GFS/ECMWF DEVELOP A
REX BLOCK OVER THE EASTERN CONUS WED/THU. THEY DEPICT A MID LEVEL
RIDGE SETTING UP OVER THE GREAT LAKES...OH VALLEY AND MID-ATLANTIC
REGIONS WITH SOUTHERN STREAM 5H LOW STALLING OVER THE CENTRAL GULF
COAST. AT THIS POINT THE PATTERN SLOWLY EVOLVES TO AN OMEGA BLOCK
LATE IN THE WEEK. THE 5H LOW IN THE GULF COAST DRIFTS WEST AND
STARTS TO FILL. AT THE SAME TIME A 5H LOW DIGS SOUTH FROM CANADA
INTO TX AS ANOTHER DROPS SOUTH FROM THE CANADIAN MARITIMES TO THE
WESTERN ATLANTIC. WITH SUCH A COMPLICATED PATTERN ALOFT THE LOCAL
FORECAST BECOMES QUITE TRICKY. CURRENTLY BOTH THE GFS/ECMWF HAVE THE
CAROLINAS IN THE RIDGING PORTION OF THE BLOCK WITH DEEP DRY AIR AND
SUBSIDENCE KEEPING THE REGION NEARLY PRECIP FREE. A SLIGHT SHIFT IN
THE LOCATION OF THE MID LEVEL FEATURES WOULD RESULT IN A DRASTICALLY
DIFFERENT OUTCOME FOR THE LOCAL AREA. GIVEN THE HIGH AMOUNT OF
UNCERTAINTY WILL MAINTAIN THE INHERITED DIURNAL CHANCE POP WITH
TEMPERATURES NEAR TO BELOW CLIMO.

&&

.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
AS OF 18Z...LIGHT RADAR RETURNS OVER THE INLAND PORTIONS OF THE
FORECAST AREA HAS PRODUCED BRIEF PERIODS OF -RA AT KFLO THIS
MORNING AND LBT THIS AFTERNOON. CURRENTLY VFR AT ALL TERMS WITH
MAINLY MID-LEVEL CIGS AROUND 10KFT AND SCT LOWER CLOUDS AROUND 5K
FT ESPECIALLY INLAND WHERE VIRGA IS LIKELY OCCURRING. EXPECT BRIEF
PERIODS OF -RA TO CONTINUE AT KFLO/KLBT THIS AFTERNOON. ALONG THE
COAST...THE DRIER LOW LEVELS COMPARED TO INLAND...WILL PREVENT
PCPN FROM REACHING THE SFC UNTIL AFTER 00Z. RAIN CHANCES INCREASE
TONIGHT AS THE SHORTWAVE TO OUR WEST MOVES CLOSER TO THE
CAROLINAS. HRRR INDICATES SHOWER ACTIVITY AND COVERAGE WILL
INCREASE OVERNIGHT INTO MON. MVFR CIGS...WITH IFR LATE...CIGS
WILL LIKELY DEVELOP AS THE COLUMN SATURATES AND RAINFALL
PERSISTS... BEGINNING AT KFLO/KLBT. EXPECT LIGHT STRATIFORM RAINS
THIS AFTERNOON THROUGH THE OVERNITE...WITH POCKETS OF MODERATE RW.
CONVECTIVE TYPE PCPN WILL BECOME MORE DOMINANT AFTER DAYBREAK MON
AS THE ATM DESTABILIZES.

EXTENDED OUTLOOK...SHOWERS/ISO TSTMS LIKELY WITH MVFR/IFR POSSIBLE
THROUGH MONDAY NIGHT. CHANCE OF SHOWERS TUESDAY AND WEDNESDAY.
SLIGHT RAIN CHANCES LINGER FOR MUCH OF THE EXTENDED PERIOD.

&&

.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 1000 AM SUNDAY...THE NOSE OF HIGH PRESSURE EXTENDING ACROSS
THE EASTERN CAROLINAS FROM THE NE IS PROGGED TO SLIDE JUST
OFFSHORE TODAY AS A WEAK SFC TROF DEVELOPS OVERNIGHT AND EXTENDS
FROM WSW TO ENE ACROSS THE CAROLINAS...MIMICKING A WARM FRONT.
LOOK FOR WINDS TO VEER FROM ENE-E TODAY TO ESE TO SE TONIGHT.
THE LATEST HRRR AND NAM ILLUSTRATE THIS TREND. OVERALL...THIS WILL
CONTINUE THE ONSHORE TYPE FLOW COVERING A DECENT FETCH. EXPECT 3 TO
4 FOOT SIGNIFICANT SEAS TODAY...WITH 5 FOOTERS OFF CAPE FEAR. A 2
TO 3 FOOT ESE GROUND SWELL EXHIBITING 13 TO 15 SECOND PERIODS WILL
DOMINATE SIGNIFICANT SEAS. TWO TO 3 FOOT WIND DRIVEN WAVES AT 5 TO 7
SECOND PERIODS...COULD PUSH SIGNIFICANT SEAS TO 5 FOOT ACROSS A
LARGER REAL ESTATE AREA OTHER THAN THE WATERS OFF CAPE FEAR. WILL
NEED TO MONITOR. STRATIFORM PCPN WILL WEAKEN AND BREAK-UP AS IT
MOVES OFF THE MAINLAND THIS AFTERNOON. HOWEVER...TONIGHT THE PCPN
MOVING OFF THE MAINLAND WILL HAVE BETTER DYNAMICS ALOFT TO WORK
WITH...AND THUS NOT BREAK UP/DISSIPATE.

SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AS OF 3 AM SUNDAY...SOLID 15 KT SOUTHERLY FLOW EXPECTED ON MON AS
GRADIENT OVER THE WATERS BECOMES PINCHED. MID LEVEL TROUGH MOVES
OFF THE COAST MON NIGHT INTO TUE. EARLY TUE PINCHED GRADIENT
SHIFTS EAST OF THE WATERS...LEAVING AN ILL DEFINED GRADIENT
BEHIND. WINDS WILL DROP UNDER 10 KT FOR TUE/TUE NIGHT WITH
DIRECTION BECOMING VARIABLE. SEABREEZE WILL INDUCE ONSHORE WINDS
NEAR SHORE ALONG WITH AN INCREASE IN WIND SPEEDS TUE AFTERNOON.
SEAS WILL RUN 3 TO 5 FT EARLY IN THE PERIOD BUT START A SLOW
DECREASE AS WIND SPEEDS START TO DROP LATE MON NIGHT. SEAS WILL BE
2 TO 4 FT TUE/TUE NIGHT.

LONG TERM /WEDNESDAY THROUGH THURSDAY/...
AS OF 3 AM SUNDAY...LIGHT NORTHEAST FLOW DEVELOPS EARLY WED AS HIGH
PRESSURE BUILDS IN FROM THE NORTHEAST. SPEEDS START OUT AROUND 10 KT
BUT INCREASE DURING WED AS GRADIENT TIGHTENS. BY THU MORNING
NORTHEAST WINDS WILL BE 15 TO 20 KT WITH A SOLID 20 KT BY THE END OF
THU. PROLONGED AND INCREASING NORTHEAST FLOW WILL BUILD SEAS FROM 3
TO 5 FT WED/WED NIGHT TO 4 TO 7 FT THU/THU NIGHT.

&&

.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.

&&

$$
SYNOPSIS...III
NEAR TERM...DCH/TRA
SHORT TERM...III
LONG TERM...III
AVIATION...DCH/BJR








AREA FORECAST DISCUSSION

NWS WILMINGTON NC

 1052 AM EDT SUN APR 28 2013

.SYNOPSIS...
A SERIES OF DISORGANIZED LOW PRESSURE AREAS WILL BRING AN INCREASED
CHANCE OF SHOWERS AND THUNDERSTORMS THROUGH MONDAY. A DRYING TREND
IS EXPECTED DURING THE MIDDLE OF THE WEEK. A BACKDOOR COLD FRONT
WILL DROP SOUTH THROUGH THE AREA WEDNESDAY...AND A SECOND FRONT WILL
APPROACH FROM THE WEST LATE NEXT WEEKEND.

&&

.NEAR TERM /THROUGH TONIGHT/...
AS OF 1000 AM SUNDAY...TIMING OF PCPN AND CLOUDINESS OVERSPREADING
THE FORECAST AREA THROUGH TONIGHT ARE THE MAIN PARAMETERS NEEDING
UPDATES. EXTRAPOLATED USING THE LATEST TRENDS/LOOPS OF THE 88D
RADAR MOSAIC AND VISIBLE SATELLITE IMAGERY...AND IN ADDITION THE
LATEST HOURLY HRRR UPDATES. STRATIFORM LIGHT RAIN WILL CONTINUE AS
THE MAIN PCPN TYPE...WITH ISOLATED THUNDER POSSIBLE THIS
AFTERNOON THROUGH TONIGHT ASSOCIATED WITH WEAK DYNAMICS FROM THE
PASSAGE OF THOSE WEAK MID LEVEL VORT LOBES. HAVE ALSO UPDATED QPF
FIELDS TO ACCOUNT FOR THE PCPN TIMING...BUT IN GENERAL HAVE KEPT
THE 24 HR AMOUNTS IN TUNE TO THE PREVIOUS FCST.

PREVIOUS DISCUSSION................................................
AS OF 630 AM SUNDAY...RADAR SHOWS A BATCH OF MAINLY LIGHT RAIN
MOVING THROUGH THE SC SAND HILLS AND APPROACHING FLORENCE. MEASURABLE
RAIN IS REACHING THE GROUND AS SHOWN BY THE .02 INCH HOURLY AMOUNT
JUST MEASURED AT THE KCDN AWOS. MUCH LIKE WE SAW YESTERDAY THIS RAIN
SHOULD LOSE ITS PUNCH AS IT MOVES EASTWARD INTO DRIER LOW LEVELS
EAST OF THE MID AND UPPER LEVEL RIDGE AXIS. THE LATEST FEW HRRR RUNS
SUGGEST WE`LL SEE A BREAK IN PRECIPITATION EVEN ACROSS THE PEE DEE
REGION FROM NOON THROUGH MID AFTERNOON...WITH A MUCH MORE
SUBSTANTIAL BAND OF SHOWERS PUSHING TOWARD THE I-95 CORRIDOR BY
EARLY EVENING. NO CHANGES HAVE BEEN MADE TO TEMPERATURE FORECASTS...
BUT IT WILL BE INTERESTING TO SEE HOW MUCH OPAQUE CLOUD COVER HANGS
AROUND BEYOND NOON IF THERE IS INDEED A SIZABLE BREAK IN
PRECIPITATION. THIS COULD HAVE IMPACTS ON HIGH TEMPERATURE FORECASTS
TOO. PREVIOUS DISCUSSION FROM 300 AM FOLLOWS...

SURFACE HIGH PRESSURE STALLED OFF THE NEW ENGLAND COASTLINE
CONTINUES TO FEED HEAVILY MODIFIED BUT STILL QUITE DRY ARCTIC AIR
SOUTHWARD ACROSS THE WESTERN ATLANTIC. THIS FLOW OF AIR IS THEN
ADVECTING INTO THE EASTERN CAROLINAS WHERE IT HAS EATEN UP AT LEAST
THREE EASTWARD-MOVING WAVES OF RAIN OVER THE 24 HOURS. YET ANOTHER
BATCH OF RAIN CURRENTLY ENTERING WESTERN SOUTH CAROLINA WILL LIKELY
FEEL THE EFFECTS OF THIS DRY AIR LATER THIS MORNING. MY FORECAST HAS
RAIN CHANCES HIGHEST WEST OF I-95...WITH VERY LITTLE PRECIPITATION
POTENTIAL DOWN AT THE COAST.

THE UPPER LEVEL PATTERN SHOWS A LOW ACROSS ILLINOIS WITH A SOUTHERN
STREAM RIDGE OVER THE CAROLINAS. WEAK SOUTHERN STREAM DISTURBANCES
ALOFT ARE DAMPING OUT AS THEY MOVE THROUGH THIS RIDGE POSITION IN
THE JET...BUT PLENTY OF GULF MOISTURE BEING LIFTED INTO THE MIDDLE
AND UPPER LEVELS OF THE ATMOSPHERE IS SUPPORTING A BROAD ZONE OF
CLOUDS WITH AREAS OF RAIN ACROSS GEORGIA AND THE WESTERN CAROLINAS.
THE UPPER RIDGE IS EXPECTED TO PUSH OFFSHORE TONIGHT...ALLOWING THE
INCOMING DISTURBANCES AND MOISTURE STREAM TO REACH THE EASTERN
CAROLINAS MORE INTACT. ALSO OF IMPORTANCE ARE TWO JET STREAKS WHICH
TONIGHT MOVE INTO FAVORABLE POSITIONS (FLORIDA PANHANDLE AND
CHESAPEAKE BAY REGION) FOR BOTH TO PROVIDE ADDITIONAL SYNOPTIC LIFT
FOR PRECIPITATION LOCALLY. FOR THIS REASON I HAVE POPS FORECAST AT
100 PERCENT ACROSS THE I-95 CORRIDOR THIS AFTERNOON AND TONIGHT...
WITH RAIN CHANCES FINALLY INCREASING TO 60-70 PERCENT AT THE COAST
LATE TONIGHT.

CLOUDS AND ONSHORE WINDS WILL HELP CONSTRAIN DIURNAL RANGES...WITH
DAYTIME HIGHS 68-73 AND LOWS TONIGHT 58-63.

&&

.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AS OF 3 AM SUNDAY...MID LEVEL RIDGE TO THE EAST AND TROUGHING TO THE
WEST SETS UP DEEP SOUTHWEST FLOW ALOFT WHICH PUSHES GULF MOISTURE
INTO THE REGION MON/MON NIGHT. MEANWHILE AT THE SURFACE HIGH
PRESSURE OFF THE EASTERN US COAST WILL ADVECT LOW LEVEL ATLANTIC
MOISTURE INTO REGION. DEEP MOISTURE...DIVERGENT FLOW ALOFT...WEAK
COASTAL TROUGH(WHICH MAY OR MAY NOT MOVE ONSHORE)...AND DIURNAL
INSTABILITY SHOULD PRODUCE WIDESPREAD SHOWERS WITH ISOLATED
THUNDERSTORMS. BASED ON FORECAST SOUNDINGS DO NOT THINK UPDRAFTS
WILL BE ALL THAT STRONG SO DO NOT ANTICIPATE MUCH IN THE WAY OF
LIGHTNING...BUT INLAND AREAS WOULD BE MORE FAVORED ESPECIALLY IN THE
AFTERNOON. DO NOT ANTICIPATE ANY SEVERE WEATHER GIVEN LOW CAPE
VALUES...LACK OF ANY JETTING...AND WEAK LAPSE RATES. PRECIPITABLE
WATER VALUES WILL BE ABOUT 2 STANDARD DEVIATIONS ABOVE NORMAL SO
HEAVY RAIN COULD BE AN ISSUE.

MID LEVEL SHORTWAVE TROUGH MOVES OFF THE EAST COAST EARLY TUE.
ALTHOUGH THERE REMAINS SOME DISCREPANCY BETWEEN THE GUIDANCE
AGREEMENT ON TUE IS MUCH BETTER THAN IS WAS 24 HOURS AGO. SUBSIDENCE
BEHIND THE EXITING SHORTWAVE AND FROM WEAK MID LEVEL RIDGE BUILDING
IN FROM THE NORTHWEST HELPS DRY THE AREA FOR TUE/TUE NIGHT. LOW
LEVEL MOISTURE COMBINED WITH DIURNAL INSTABILITY COULD GENERATE A
FEW SHOWERS DURING THE AFTERNOON AND EVENING HOURS BUT COVERAGE WILL
BE CONSIDERABLY LESS THAN MON. CLOUDS AND RAIN ON MON WILL KEEP
HIGHS BELOW CLIMO BUT CLEARING EXPECTED ON TUE WILL LEAD TO HIGHS
NEAR CLIMO. LOWS WILL REMAIN ABOVE CLIMO THROUGH THE PERIOD.

&&

.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
AS OF 3 AM SUNDAY...STILL A LOT OF HAND WRINGING IN THE EXTENDED.
GFS/ECMWF HAVE COME INTO MUCH BETTER AGREEMENT OVER THE LAST DAY OR
SO BUT PITFALLS ABOUND IN THE LONG TERM. BOTH GFS/ECMWF DEVELOP A
REX BLOCK OVER THE EASTERN CONUS WED/THU. THEY DEPICT A MID LEVEL
RIDGE SETTING UP OVER THE GREAT LAKES...OH VALLEY AND MID-ATLANTIC
REGIONS WITH SOUTHERN STREAM 5H LOW STALLING OVER THE CENTRAL GULF
COAST. AT THIS POINT THE PATTERN SLOWLY EVOLVES TO AN OMEGA BLOCK
LATE IN THE WEEK. THE 5H LOW IN THE GULF COAST DRIFTS WEST AND
STARTS TO FILL. AT THE SAME TIME A 5H LOW DIGS SOUTH FROM CANADA
INTO TX AS ANOTHER DROPS SOUTH FROM THE CANADIAN MARITIMES TO THE
WESTERN ATLANTIC. WITH SUCH A COMPLICATED PATTERN ALOFT THE LOCAL
FORECAST BECOMES QUITE TRICKY. CURRENTLY BOTH THE GFS/ECMWF HAVE THE
CAROLINAS IN THE RIDGING PORTION OF THE BLOCK WITH DEEP DRY AIR AND
SUBSIDENCE KEEPING THE REGION NEARLY PRECIP FREE. A SLIGHT SHIFT IN
THE LOCATION OF THE MID LEVEL FEATURES WOULD RESULT IN A DRASTICALLY
DIFFERENT OUTCOME FOR THE LOCAL AREA. GIVEN THE HIGH AMOUNT OF
UNCERTAINTY WILL MAINTAIN THE INHERITED DIURNAL CHANCE POP WITH
TEMPERATURES NEAR TO BELOW CLIMO.

&&

.AVIATION /14Z SUNDAY THROUGH THURSDAY/...
AS OF 12Z...CURRENT RADAR IMAGERY SHOWS SOME -RA MOVING INTO OUR
WESTERN COUNTIES. KFLO/KLBT WILL SEE LIGHT PCPN THIS MORNING...WHILE
DRIER LOW-LEVEL AIR NEAR THE COAST WILL LIKELY PREVENT MUCH FROM
REACHING THE SFC AT KILM/KMYR/KCRE.

A BROAD AREA OF ISENTROPIC ASCENT WILL PRODUCE AREAS OF LIGHT
RAINFALL THAT WILL IMPACT OUR CWA THRU THE DAY. EXPECT MAINLY VFR
CIGS INTO THE AFTN HOURS...BECOMING MVFR INLAND THIS EVENING AS THE
APPROACHING SHORTWAVE BRINGS MORE PCPN TO OUR CWA. RAIN CHANCES
INCREASE AREA-WIDE EARLY MONDAY AS A SFC LOW DEVELOPS OVER THE
WESTERN CAROLINAS. -SHRA IS EXPECTED AFTER 06Z MONDAY ALONG WITH
MVFR CIGS...POSSIBLY NEARING IFR LEVELS INLAND. EAST WINDS AOB 10
KTS THIS MORNING WILL VEER TO THE SOUTHEAST THIS AFTN AND THE
SOUTH OVERNIGHT...LIKELY REMAINING AROUND 10 KTS THROUGHOUT.

EXTENDED OUTLOOK...SHOWERS/ISO TSTMS LIKELY WITH MVFR/IFR POSSIBLE
MONDAY AND EARLY TUESDAY. A SLIGHT CHANCE OF SHOWERS LINGERS FOR THE
REST OF THE EXTENDED PERIOD.

&&

.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 1000 AM SUNDAY...THE NOSE OF HIGH PRESSURE EXTENDING ACROSS
THE EASTERN CAROLINAS FROM THE NE IS PROGGED TO SLIDE JUST
OFFSHORE TODAY AS A WEAK SFC TROF DEVELOPS OVERNIGHT AND EXTENDS
FROM WSW TO ENE ACROSS THE CAROLINAS...MIMICKING A WARM FRONT.
LOOK FOR WINDS TO VEER FROM ENE-E TODAY TO ESE TO SE TONIGHT.
THE LATEST HRRR AND NAM ILLUSTRATE THIS TREND. OVERALL...THIS WILL
CONTINUE THE ONSHORE TYPE FLOW COVERING A DECENT FETCH. EXPECT 3 TO
4 FOOT SIGNIFICANT SEAS TODAY...WITH 5 FOOTERS OFF CAPE FEAR. A 2
TO 3 FOOT ESE GROUND SWELL EXHIBITING 13 TO 15 SECOND PERIODS WILL
DOMINATE SIGNIFICANT SEAS. TWO TO 3 FOOT WIND DRIVEN WAVES AT 5 TO 7
SECOND PERIODS...COULD PUSH SIGNIFICANT SEAS TO 5 FOOT ACROSS A
LARGER REAL ESTATE AREA OTHER THAN THE WATERS OFF CAPE FEAR. WILL
NEED TO MONITOR. STRATIFORM PCPN WILL WEAKEN AND BREAK-UP AS IT
MOVES OFF THE MAINLAND THIS AFTERNOON. HOWEVER...TONIGHT THE PCPN
MOVING OFF THE MAINLAND WILL HAVE BETTER DYNAMICS ALOFT TO WORK
WITH...AND THUS NOT BREAK UP/DISSIPATE.

SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AS OF 3 AM SUNDAY...SOLID 15 KT SOUTHERLY FLOW EXPECTED ON MON AS
GRADIENT OVER THE WATERS BECOMES PINCHED. MID LEVEL TROUGH MOVES
OFF THE COAST MON NIGHT INTO TUE. EARLY TUE PINCHED GRADIENT
SHIFTS EAST OF THE WATERS...LEAVING AN ILL DEFINED GRADIENT
BEHIND. WINDS WILL DROP UNDER 10 KT FOR TUE/TUE NIGHT WITH
DIRECTION BECOMING VARIABLE. SEABREEZE WILL INDUCE ONSHORE WINDS
NEAR SHORE ALONG WITH AN INCREASE IN WIND SPEEDS TUE AFTERNOON.
SEAS WILL RUN 3 TO 5 FT EARLY IN THE PERIOD BUT START A SLOW
DECREASE AS WIND SPEEDS START TO DROP LATE MON NIGHT. SEAS WILL BE
2 TO 4 FT TUE/TUE NIGHT.

LONG TERM /WEDNESDAY THROUGH THURSDAY/...
AS OF 3 AM SUNDAY...LIGHT NORTHEAST FLOW DEVELOPS EARLY WED AS HIGH
PRESSURE BUILDS IN FROM THE NORTHEAST. SPEEDS START OUT AROUND 10 KT
BUT INCREASE DURING WED AS GRADIENT TIGHTENS. BY THU MORNING
NORTHEAST WINDS WILL BE 15 TO 20 KT WITH A SOLID 20 KT BY THE END OF
THU. PROLONGED AND INCREASING NORTHEAST FLOW WILL BUILD SEAS FROM 3
TO 5 FT WED/WED NIGHT TO 4 TO 7 FT THU/THU NIGHT.

&&

.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.

&&

$$
SYNOPSIS...
NEAR TERM...DCH/TRA
SHORT TERM...III
LONG TERM...III
AVIATION...BJR
MARINE...







AREA FORECAST DISCUSSION

NWS WILMINGTON NC

 749 AM EDT SUN APR 28 2013

.SYNOPSIS...
A SERIES OF DISORGANIZED LOW PRESSURE AREAS WILL BRING AN INCREASED
CHANCE OF SHOWERS AND THUNDERSTORMS THROUGH MONDAY. A DRYING TREND
IS EXPECTED DURING THE MIDDLE OF THE WEEK. A BACKDOOR COLD FRONT
WILL DROP SOUTH THROUGH THE AREA WEDNESDAY...AND A SECOND FRONT WILL
APPROACH FROM THE WEST LATE NEXT WEEKEND.

&&

.NEAR TERM /THROUGH TONIGHT/...
AS OF 630 AM SUNDAY...RADAR SHOWS A BATCH OF MAINLY LIGHT RAIN
MOVING THROUGH THE SC SANDHILLS AND APPROACHING FLORENCE. MEASURABLE
RAIN IS REACHING THE GROUND AS SHOWN BY THE .02 INCH HOURLY AMOUNT
JUST MEASURED AT THE KCDN AWOS. MUCH LIKE WE SAW YESTERDAY THIS RAIN
SHOULD LOSE ITS PUNCH AS IT MOVES EASTWARD INTO DRIER LOW LEVELS
EAST OF THE MID AND UPPER LEVEL RIDGE AXIS. THE LATEST FEW HRRR RUNS
SUGGEST WE`LL SEE A BREAK IN PRECIPITATION EVEN ACROSS THE PEE DEE
REGION FROM NOON THROUGH MID AFTERNOON...WITH A MUCH MORE
SUBSTANTIAL BAND OF SHOWERS PUSHING TOWARD THE I-95 CORRIDOR BY
EARLY EVENING. NO CHANGES HAVE BEEN MADE TO TEMPERATURE FORECASTS...
BUT IT WILL BE INTERESTING TO SEE HOW MUCH OPAQUE CLOUD COVER HANGS
AROUND BEYOND NOON IF THERE IS INDEED A SIZABLE BREAK IN
PRECIPITATION. THIS COULD HAVE IMPACTS ON HIGH TEMPERATURE FORECASTS
TOO. PREVIOUS DISCUSSION FROM 300 AM FOLLOWS...

SURFACE HIGH PRESSURE STALLED OFF THE NEW ENGLAND COASTLINE
CONTINUES TO FEED HEAVILY MODIFIED BUT STILL QUITE DRY ARCTIC AIR
SOUTHWARD ACROSS THE WESTERN ATLANTIC. THIS FLOW OF AIR IS THEN
ADVECTING INTO THE EASTERN CAROLINAS WHERE IT HAS EATEN UP AT LEAST
THREE EASTWARD-MOVING WAVES OF RAIN OVER THE 24 HOURS. YET ANOTHER
BATCH OF RAIN CURRENTLY ENTERING WESTERN SOUTH CAROLINA WILL LIKELY
FEEL THE EFFECTS OF THIS DRY AIR LATER THIS MORNING. MY FORECAST HAS
RAIN CHANCES HIGHEST WEST OF I-95...WITH VERY LITTLE PRECIPITATION
POTENTIAL DOWN AT THE COAST.

THE UPPER LEVEL PATTERN SHOWS A LOW ACROSS ILLINOIS WITH A SOUTHERN
STREAM RIDGE OVER THE CAROLINAS. WEAK SOUTHERN STREAM DISTURBANCES
ALOFT ARE DAMPING OUT AS THEY MOVE THROUGH THIS RIDGE POSITION IN
THE JET...BUT PLENTY OF GULF MOISTURE BEING LIFTED INTO THE MIDDLE
AND UPPER LEVELS OF THE ATMOSPHERE IS SUPPORTING A BROAD ZONE OF
CLOUDS WITH AREAS OF RAIN ACROSS GEORGIA AND THE WESTERN CAROLINAS.
THE UPPER RIDGE IS EXPECTED TO PUSH OFFSHORE TONIGHT...ALLOWING THE
INCOMING DISTURBANCES AND MOISTURE STREAM TO REACH THE EASTERN
CAROLINAS MORE INTACT. ALSO OF IMPORTANCE ARE TWO JET STREAKS WHICH
TONIGHT MOVE INTO FAVORABLE POSITIONS (FLORIDA PANHANDLE AND
CHESAPEAKE BAY REGION) FOR BOTH TO PROVIDE ADDITIONAL SYNOPTIC LIFT
FOR PRECIPITATION LOCALLY. FOR THIS REASON I HAVE POPS FORECAST AT
100 PERCENT ACROSS THE I-95 CORRIDOR THIS AFTERNOON AND TONIGHT...
WITH RAIN CHANCES FINALLY INCREASING TO 60-70 PERCENT AT THE COAST
LATE TONIGHT.

CLOUDS AND ONSHORE WINDS WILL HELP CONSTRAIN DIURNAL RANGES...WITH
DAYTIME HIGHS 68-73 AND LOWS TONIGHT 58-63.

&&

.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AS OF 3 AM SUNDAY...MID LEVEL RIDGE TO THE EAST AND TROUGHING TO THE
WEST SETS UP DEEP SOUTHWEST FLOW ALOFT WHICH PUSHES GULF MOISTURE
INTO THE REGION MON/MON NIGHT. MEANWHILE AT THE SURFACE HIGH
PRESSURE OFF THE EASTERN US COAST WILL ADVECT LOW LEVEL ATLANTIC
MOISTURE INTO REGION. DEEP MOISTURE...DIVERGENT FLOW ALOFT...WEAK
COASTAL TROUGH(WHICH MAY OR MAY NOT MOVE ONSHORE)...AND DIURNAL
INSTABILITY SHOULD PRODUCE WIDESPREAD SHOWERS WITH ISOLATED
THUNDERSTORMS. BASED ON FORECAST SOUNDINGS DO NOT THINK UPDRAFTS
WILL BE ALL THAT STRONG SO DO NOT ANTICIPATE MUCH IN THE WAY OF
LIGHTNING...BUT INLAND AREAS WOULD BE MORE FAVORED ESPECIALLY IN THE
AFTERNOON. DO NOT ANTICIPATE ANY SEVERE WEATHER GIVEN LOW CAPE
VALUES...LACK OF ANY JETTING...AND WEAK LAPSE RATES. PRECIPITABLE
WATER VALUES WILL BE ABOUT 2 STANDARD DEVIATIONS ABOVE NORMAL SO
HEAVY RAIN COULD BE AN ISSUE.

MID LEVEL SHORTWAVE TROUGH MOVES OFF THE EAST COAST EARLY TUE.
ALTHOUGH THERE REMAINS SOME DISCREPANCY BETWEEN THE GUIDANCE
AGREEMENT ON TUE IS MUCH BETTER THAN IS WAS 24 HOURS AGO. SUBSIDENCE
BEHIND THE EXITING SHORTWAVE AND FROM WEAK MID LEVEL RIDGE BUILDING
IN FROM THE NORTHWEST HELPS DRY THE AREA FOR TUE/TUE NIGHT. LOW
LEVEL MOISTURE COMBINED WITH DIURNAL INSTABILITY COULD GENERATE A
FEW SHOWERS DURING THE AFTERNOON AND EVENING HOURS BUT COVERAGE WILL
BE CONSIDERABLY LESS THAN MON. CLOUDS AND RAIN ON MON WILL KEEP
HIGHS BELOW CLIMO BUT CLEARING EXPECTED ON TUE WILL LEAD TO HIGHS
NEAR CLIMO. LOWS WILL REMAIN ABOVE CLIMO THROUGH THE PERIOD.

&&

.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
AS OF 3 AM SUNDAY...STILL A LOT OF HAND WRINGING IN THE EXTENDED.
GFS/ECMWF HAVE COME INTO MUCH BETTER AGREEMENT OVER THE LAST DAY OR
SO BUT PITFALLS ABOUND IN THE LONG TERM. BOTH GFS/ECMWF DEVELOP A
REX BLOCK OVER THE EASTERN CONUS WED/THU. THEY DEPICT A MID LEVEL
RIDGE SETTING UP OVER THE GREAT LAKES...OH VALLEY AND MID-ATLANTIC
REGIONS WITH SOUTHERN STREAM 5H LOW STALLING OVER THE CENTRAL GULF
COAST. AT THIS POINT THE PATTERN SLOWLY EVOLVES TO AN OMEGA BLOCK
LATE IN THE WEEK. THE 5H LOW IN THE GULF COAST DRIFTS WEST AND
STARTS TO FILL. AT THE SAME TIME A 5H LOW DIGS SOUTH FROM CANADA
INTO TX AS ANOTHER DROPS SOUTH FROM THE CANADIAN MARITIMES TO THE
WESTERN ATLANTIC. WITH SUCH A COMPLICATED PATTERN ALOFT THE LOCAL
FORECAST BECOMES QUITE TRICKY. CURRENTLY BOTH THE GFS/ECMWF HAVE THE
CAROLINAS IN THE RIDGING PORTION OF THE BLOCK WITH DEEP DRY AIR AND
SUBSIDENCE KEEPING THE REGION NEARLY PRECIP FREE. A SLIGHT SHIFT IN
THE LOCATION OF THE MID LEVEL FEATURES WOULD RESULT IN A DRASTICALLY
DIFFERENT OUTCOME FOR THE LOCAL AREA. GIVEN THE HIGH AMOUNT OF
UNCERTAINTY WILL MAINTAIN THE INHERITED DIURNAL CHANCE POP WITH
TEMPERATURES NEAR TO BELOW CLIMO.

&&

.AVIATION /12Z SUNDAY THROUGH THURSDAY/...
AS OF 12Z...CURRENT RADAR IMAGERY SHOWS SOME -RA MOVING INTO OUR
WESTERN COUNTIES. KFLO/KLBT WILL SEE LIGHT PCPN THIS MORNING...WHILE
DRIER LOW-LEVEL AIR NEAR THE COAST WILL LIKELY PREVENT MUCH FROM
REACHING THE SFC AT KILM/KMYR/KCRE.

A BROAD AREA OF ISENTROPIC ASCENT WILL PRODUCE AREAS OF LIGHT
RAINFALL THAT WILL IMPACT OUR CWA THRU THE DAY. EXPECT MAINLY VFR
CIGS INTO THE AFTN HOURS...BECOMING MVFR INLAND THIS EVENING AS THE
APPROACHING SHORTWAVE BRINGS MORE PCPN TO OUR CWA. RAIN CHANCES
INCREASE AREA-WIDE EARLY MONDAY AS A SFC LOW DEVELOPS OVER THE
WESTERN CAROLINAS. -SHRA IS EXPECTED AFTER 06Z MONDAY ALONG WITH
MVFR CIGS...POSSIBLY NEARING IFR LEVELS INLAND. EAST WINDS AOB 10
KTS THIS MORNING WILL VEER TO THE SOUTHEAST THIS AFTN AND THE
SOUTH OVERNIGHT...LIKELY REMAINING AROUND 10 KTS THROUGHOUT.

EXTENDED OUTLOOK...SHOWERS/ISO TSTMS LIKELY WITH MVFR/IFR POSSIBLE
MONDAY AND EARLY TUESDAY. A SLIGHT CHANCE OF SHOWERS LINGERS FOR THE
REST OF THE EXTENDED PERIOD.

&&

.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 630 AM SUNDAY...WITH MISSING DATA FROM THE NEARSHORE
WRIGHTSVILLE BEACH BUOY AND FROM THE WAVE GAUGE ON THE OCEAN CREST
PIER AT OAK ISLAND...THIS EARLY MORNING UPDATE IS BASED ON DATA
MAINLY FROM THE FRYING PAN SHOALS BUOY AND FROM NOS PIER SITES AT
WRIGHTSVILLE BEACH AND MYRTLE BEACH. E TO NE WINDS 10 KNOTS
NEARSHORE TO 16 KNOTS OUT AT FRYING PAN SUPPORT MY EARLIER FORECAST.
A GRADUAL VEERING IS EXPECTED THROUGHOUT THE DAY...BEGINNING FIRST
OVER THE SC COASTAL WATERS AND PROCEEDING NORTHWARD THIS AFTERNOON.
NO SIGNIFICANT CHANGES HAVE BEEN MADE TO THE FORECAST. PREVIOUS
DISCUSSION FROM 300 AM FOLLOWS...

HIGH PRESSURE SITTING OFF THE NEW ENGLAND COAST WILL MOVE LITTLE
THROUGH TONIGHT...MAINTAINING A SURFACE RIDGE JUST WEST OF 70
DEGREES LONGITUDE. A BROAD ZONE OF LOW PRESSURE OVER THE MIDWEST
WILL HELP VEER SURFACE WINDS MORE SOUTHERLY WITH TIME...ESPECIALLY
TONIGHT. THE GRADIENT IS TIGHT ENOUGH TO MAINTAIN AN AVERAGE WIND
SPEED OF 15 KNOTS THROUGH THE PERIOD...WHICH GIVEN THE LONG ONSHORE
TRAJECTORIES WILL MAINTAIN SEAS AT 3-4 FT TONIGHT...BUILDING TO 4-5
FT TONIGHT. BLENDING OUR LOCAL SWAN MODEL WITH WAVEWATCH OUTPUT
PLACES 6 FOOT SEAS JUST OUTSIDE OF THE COASTAL WATERS AT CAPE FEAR
AFTER MIDNIGHT TONIGHT. IF WINDS ARE ONLY A LITTLE STRONGER THAN
FORECAST SMALL CRAFT ADVISORIES MAY BE NEEDED FOR THIS AREA.

SHOWERS DEVELOPING OVER THE GULF STREAM WILL LARGELY DISSIPATE AS
THEY DRIFT WESTWARD OVER THE COOLER CONTINENTAL SHELF WATERS. A
LARGE AREA OF RAIN AND EMBEDDED HEAVIER SHOWERS IS EXPECTED TO PUSH
INTO THE COASTAL WATERS LATE TONIGHT HOWEVER.

SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AS OF 3 AM SUNDAY...SOLID 15 KT SOUTHERLY FLOW EXPECTED ON MON AS
GRADIENT OVER THE WATERS BECOMES PINCHED. MID LEVEL TROUGH MOVES OFF
THE COAST MON NIGHT INTO TUE. EARLY TUE PINCHED GRADIENT SHIFTS EAST
OF THE WATERS...LEAVING AN ILL DEFINED GRADIENT BEHIND. WINDS WILL
DROP UNDER 10 KT FOR TUE/TUE NIGHT WITH DIRECTION BECOMING VARIABLE.
SEABREEZE WILL INDUCE ONSHORE WINDS NEAR SHORE ALONG WITH AN
INCREASE IN WIND SPEEDS TUE AFTERNOON. SEAS WILL RUN 3 TO 5 FT EARLY
IN THE PERIOD BUT START A SLOW DECREASE AS WIND SPEEDS START TO DROP
LATE MON NIGHT. SEAS WILL BE 2 TO 4 FT TUE/TUE NIGHT.

LONG TERM /WEDNESDAY THROUGH THURSDAY/...
AS OF 3 AM SUNDAY...LIGHT NORTHEAST FLOW DEVELOPS EARLY WED AS HIGH
PRESSURE BUILDS IN FROM THE NORTHEAST. SPEEDS START OUT AROUND 10 KT
BUT INCREASE DURING WED AS GRADIENT TIGHTENS. BY THU MORNING
NORTHEAST WINDS WILL BE 15 TO 20 KT WITH A SOLID 20 KT BY THE END OF
THU. PROLONGED AND INCREASING NORTHEAST FLOW WILL BUILD SEAS FROM 3
TO 5 FT WED/WED NIGHT TO 4 TO 7 FT THU/THU NIGHT.

&&

.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.

&&

$$

NEAR TERM...TRA
SHORT TERM...III
LONG TERM...III
AVIATION...BJR








AREA FORECAST DISCUSSION

NWS WILMINGTON NC

 641 AM EDT SUN APR 28 2013

.SYNOPSIS...
A SERIES OF DISORGANIZED LOW PRESSURE AREAS WILL BRING AN INCREASED
CHANCE OF SHOWERS AND THUNDERSTORMS THROUGH MONDAY. A DRYING TREND
IS EXPECTED DURING THE MIDDLE OF THE WEEK. A BACKDOOR COLD FRONT
WILL DROP SOUTH THROUGH THE AREA WEDNESDAY...AND A SECOND FRONT WILL
APPROACH FROM THE WEST LATE NEXT WEEKEND.

&&

.NEAR TERM /THROUGH TONIGHT/...
AS OF 630 AM SUNDAY...RADAR SHOWS A BATCH OF MAINLY LIGHT RAIN
MOVING THROUGH THE SC SANDHILLS AND APPROACHING FLORENCE. MEASURABLE
RAIN IS REACHING THE GROUND AS SHOWN BY THE .02 INCH HOURLY AMOUNT
JUST MEASURED AT THE KCDN AWOS. MUCH LIKE WE SAW YESTERDAY THIS RAIN
SHOULD LOSE ITS PUNCH AS IT MOVES EASTWARD INTO DRIER LOW LEVELS
EAST OF THE MID AND UPPER LEVEL RIDGE AXIS. THE LATEST FEW HRRR RUNS
SUGGEST WE`LL SEE A BREAK IN PRECIPITATION EVEN ACROSS THE PEE DEE
REGION FROM NOON THROUGH MID AFTERNOON...WITH A MUCH MORE
SUBSTANTIAL BAND OF SHOWERS PUSHING TOWARD THE I-95 CORRIDOR BY
EARLY EVENING. NO CHANGES HAVE BEEN MADE TO TEMPERATURE FORECASTS...
BUT IT WILL BE INTERESTING TO SEE HOW MUCH OPAQUE CLOUD COVER HANGS
AROUND BEYOND NOON IF THERE IS INDEED A SIZABLE BREAK IN
PRECIPITATION. THIS COULD HAVE IMPACTS ON HIGH TEMPERATURE FORECASTS
TOO. PREVIOUS DISCUSSION FROM 300 AM FOLLOWS...

SURFACE HIGH PRESSURE STALLED OFF THE NEW ENGLAND COASTLINE
CONTINUES TO FEED HEAVILY MODIFIED BUT STILL QUITE DRY ARCTIC AIR
SOUTHWARD ACROSS THE WESTERN ATLANTIC. THIS FLOW OF AIR IS THEN
ADVECTING INTO THE EASTERN CAROLINAS WHERE IT HAS EATEN UP AT LEAST
THREE EASTWARD-MOVING WAVES OF RAIN OVER THE 24 HOURS. YET ANOTHER
BATCH OF RAIN CURRENTLY ENTERING WESTERN SOUTH CAROLINA WILL LIKELY
FEEL THE EFFECTS OF THIS DRY AIR LATER THIS MORNING. MY FORECAST HAS
RAIN CHANCES HIGHEST WEST OF I-95...WITH VERY LITTLE PRECIPITATION
POTENTIAL DOWN AT THE COAST.

THE UPPER LEVEL PATTERN SHOWS A LOW ACROSS ILLINOIS WITH A SOUTHERN
STREAM RIDGE OVER THE CAROLINAS. WEAK SOUTHERN STREAM DISTURBANCES
ALOFT ARE DAMPING OUT AS THEY MOVE THROUGH THIS RIDGE POSITION IN
THE JET...BUT PLENTY OF GULF MOISTURE BEING LIFTED INTO THE MIDDLE
AND UPPER LEVELS OF THE ATMOSPHERE IS SUPPORTING A BROAD ZONE OF
CLOUDS WITH AREAS OF RAIN ACROSS GEORGIA AND THE WESTERN CAROLINAS.
THE UPPER RIDGE IS EXPECTED TO PUSH OFFSHORE TONIGHT...ALLOWING THE
INCOMING DISTURBANCES AND MOISTURE STREAM TO REACH THE EASTERN
CAROLINAS MORE INTACT. ALSO OF IMPORTANCE ARE TWO JET STREAKS WHICH
TONIGHT MOVE INTO FAVORABLE POSITIONS (FLORIDA PANHANDLE AND
CHESAPEAKE BAY REGION) FOR BOTH TO PROVIDE ADDITIONAL SYNOPTIC LIFT
FOR PRECIPITATION LOCALLY. FOR THIS REASON I HAVE POPS FORECAST AT
100 PERCENT ACROSS THE I-95 CORRIDOR THIS AFTERNOON AND TONIGHT...
WITH RAIN CHANCES FINALLY INCREASING TO 60-70 PERCENT AT THE COAST
LATE TONIGHT.

CLOUDS AND ONSHORE WINDS WILL HELP CONSTRAIN DIURNAL RANGES...WITH
DAYTIME HIGHS 68-73 AND LOWS TONIGHT 58-63.

&&

.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AS OF 3 AM SUNDAY...MID LEVEL RIDGE TO THE EAST AND TROUGHING TO THE
WEST SETS UP DEEP SOUTHWEST FLOW ALOFT WHICH PUSHES GULF MOISTURE
INTO THE REGION MON/MON NIGHT. MEANWHILE AT THE SURFACE HIGH
PRESSURE OFF THE EASTERN US COAST WILL ADVECT LOW LEVEL ATLANTIC
MOISTURE INTO REGION. DEEP MOISTURE...DIVERGENT FLOW ALOFT...WEAK
COASTAL TROUGH(WHICH MAY OR MAY NOT MOVE ONSHORE)...AND DIURNAL
INSTABILITY SHOULD PRODUCE WIDESPREAD SHOWERS WITH ISOLATED
THUNDERSTORMS. BASED ON FORECAST SOUNDINGS DO NOT THINK UPDRAFTS
WILL BE ALL THAT STRONG SO DO NOT ANTICIPATE MUCH IN THE WAY OF
LIGHTNING...BUT INLAND AREAS WOULD BE MORE FAVORED ESPECIALLY IN THE
AFTERNOON. DO NOT ANTICIPATE ANY SEVERE WEATHER GIVEN LOW CAPE
VALUES...LACK OF ANY JETTING...AND WEAK LAPSE RATES. PRECIPITABLE
WATER VALUES WILL BE ABOUT 2 STANDARD DEVIATIONS ABOVE NORMAL SO
HEAVY RAIN COULD BE AN ISSUE.

MID LEVEL SHORTWAVE TROUGH MOVES OFF THE EAST COAST EARLY TUE.
ALTHOUGH THERE REMAINS SOME DISCREPANCY BETWEEN THE GUIDANCE
AGREEMENT ON TUE IS MUCH BETTER THAN IS WAS 24 HOURS AGO. SUBSIDENCE
BEHIND THE EXITING SHORTWAVE AND FROM WEAK MID LEVEL RIDGE BUILDING
IN FROM THE NORTHWEST HELPS DRY THE AREA FOR TUE/TUE NIGHT. LOW
LEVEL MOISTURE COMBINED WITH DIURNAL INSTABILITY COULD GENERATE A
FEW SHOWERS DURING THE AFTERNOON AND EVENING HOURS BUT COVERAGE WILL
BE CONSIDERABLY LESS THAN MON. CLOUDS AND RAIN ON MON WILL KEEP
HIGHS BELOW CLIMO BUT CLEARING EXPECTED ON TUE WILL LEAD TO HIGHS
NEAR CLIMO. LOWS WILL REMAIN ABOVE CLIMO THROUGH THE PERIOD.

&&

.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
AS OF 3 AM SUNDAY....STILL A LOT OF HAND WRINGING IN THE EXTENDED.
GFS/ECMWF HAVE COME INTO MUCH BETTER AGREEMENT OVER THE LAST DAY OR
SO BUT PITFALLS ABOUND IN THE LONG TERM. BOTH GFS/ECMWF DEVELOP A
REX BLOCK OVER THE EASTERN CONUS WED/THU. THEY DEPICT A MID LEVEL
RIDGE SETTING UP OVER THE GREAT LAKES...OH VALLEY AND MID-ATLANTIC
REGIONS WITH SOUTHERN STREAM 5H LOW STALLING OVER THE CENTRAL GULF
COAST. AT THIS POINT THE PATTERN SLOWLY EVOLVES TO AN OMEGA BLOCK
LATE IN THE WEEK. THE 5H LOW IN THE GULF COAST DRIFTS WEST AND
STARTS TO FILL. AT THE SAME TIME A 5H LOW DIGS SOUTH FROM CANADA
INTO TX AS ANOTHER DROPS SOUTH FROM THE CANADIAN MARITIMES TO THE
WESTERN ATLANTIC. WITH SUCH A COMPLICATED PATTERN ALOFT THE LOCAL
FORECAST BECOMES QUITE TRICKY. CURRENTLY BOTH THE GFS/ECMWF HAVE THE
CAROLINAS IN THE RIDGING PORTION OF THE BLOCK WITH DEEP DRY AIR AND
SUBSIDENCE KEEPING THE REGION NEARLY PRECIP FREE. A SLIGHT SHIFT IN
THE LOCATION OF THE MID LEVEL FEATURES WOULD RESULT IN A DRASTICALLY
DIFFERENT OUTCOME FOR THE LOCAL AREA. GIVEN THE HIGH AMOUNT OF
UNCERTAINTY WILL MAINTAIN THE INHERITED DIURNAL CHANCE POP WITH
TEMPERATURES NEAR TO BELOW CLIMO.

&&

.AVIATION /06Z SUNDAY THROUGH THURSDAY/...
AS OF 06Z...MOST OF THE RAIN HAS SHUT OFF AT THIS POINT...BUT A
SERIES OF WEAK DISTURBANCES WILL REGENERATE THE PRECIP BY MORNING.
THINK VISIBILITIES WILL REMAIN VFR...WITH BRIEF PERIODS OF MVFR
POSSIBLE IN MODERATE RAIN SUNDAY. THINK MOST OF THE PRECIP WILL BE
STRATIFORM...HOWEVER EMBEDDED SHOWERS ARE A POSSIBILITY. BEST CHANCE
FOR PRECIP WILL BE TOWARD THE END OF THE FORECAST PERIOD AS DEEPER
MOISTURE AND WEAK ISENTROPIC LIFT ADVECT INTO THE REGION.
PRECIPITATION INDUCED CEILINGS WILL LOWER TO MVFR BY
AFTERNOON...POSSIBLY IFR BY SUNDAY EVENING ALTHOUGH MODELS NOT IN
AGREEMENT WITH THIS SCENARIO.

EXTENDED OUTLOOK...UNSETTLED WEATHER WILL RESULT IN PERIODS OF RAIN
WITH SUB-VFR CONDITIONS POSSIBLE SUNDAY NIGHT THROUGH THURSDAY. THE
BEST RAIN CHANCES WILL BE ON MONDAY.

&&

.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 630 AM SUNDAY...WITH MISSING DATA FROM THE NEARSHORE
WRIGHTSVILLE BEACH BUOY AND FROM THE WAVE GAUGE ON THE OCEAN CREST
PIER AT OAK ISLAND...THIS EARLY MORNING UPDATE IS BASED ON DATA
MAINLY FROM THE FRYING PAN SHOALS BUOY AND FROM NOS PIER SITES AT
WRIGHTSVILLE BEACH AND MYRTLE BEACH. E TO NE WINDS 10 KNOTS
NEARSHORE TO 16 KNOTS OUT AT FRYING PAN SUPPORT MY EARLIER FORECAST.
A GRADUAL VEERING IS EXPECTED THROUGHOUT THE DAY...BEGINNING FIRST
OVER THE SC COASTAL WATERS AND PROCEEDING NORTHWARD THIS AFTERNOON.
NO SIGNIFICANT CHANGES HAVE BEEN MADE TO THE FORECAST. PREVIOUS
DISCUSSION FROM 300 AM FOLLOWS...

HIGH PRESSURE SITTING OFF THE NEW ENGLAND COAST WILL MOVE LITTLE
THROUGH TONIGHT...MAINTAINING A SURFACE RIDGE JUST WEST OF 70
DEGREES LONGITUDE. A BROAD ZONE OF LOW PRESSURE OVER THE MIDWEST
WILL HELP VEER SURFACE WINDS MORE SOUTHERLY WITH TIME...ESPECIALLY
TONIGHT. THE GRADIENT IS TIGHT ENOUGH TO MAINTAIN AN AVERAGE WIND
SPEED OF 15 KNOTS THROUGH THE PERIOD...WHICH GIVEN THE LONG ONSHORE
TRAJECTORIES WILL MAINTAIN SEAS AT 3-4 FT TONIGHT...BUILDING TO 4-5
FT TONIGHT. BLENDING OUR LOCAL SWAN MODEL WITH WAVEWATCH OUTPUT
PLACES 6 FOOT SEAS JUST OUTSIDE OF THE COASTAL WATERS AT CAPE FEAR
AFTER MIDNIGHT TONIGHT. IF WINDS ARE ONLY A LITTLE STRONGER THAN
FORECAST SMALL CRAFT ADVISORIES MAY BE NEEDED FOR THIS AREA.

SHOWERS DEVELOPING OVER THE GULF STREAM WILL LARGELY DISSIPATE AS
THEY DRIFT WESTWARD OVER THE COOLER CONTINENTAL SHELF WATERS. A
LARGE AREA OF RAIN AND EMBEDDED HEAVIER SHOWERS IS EXPECTED TO PUSH
INTO THE COASTAL WATERS LATE TONIGHT HOWEVER.

SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AS OF 3 AM SUNDAY...SOLID 15 KT SOUTHERLY FLOW EXPECTED ON MON AS
GRADIENT OVER THE WATERS BECOMES PINCHED. MID LEVEL TROUGH MOVES OFF
THE COAST MON NIGHT INTO TUE. EARLY TUE PINCHED GRADIENT SHIFTS EAST
OF THE WATERS...LEAVING AN ILL DEFINED GRADIENT BEHIND. WINDS WILL
DROP UNDER 10 KT FOR TUE/TUE NIGHT WITH DIRECTION BECOMING VARIABLE.
SEABREEZE WILL INDUCE ONSHORE WINDS NEAR SHORE ALONG WITH AN
INCREASE IN WIND SPEEDS TUE AFTERNOON. SEAS WILL RUN 3 TO 5 FT EARLY
IN THE PERIOD BUT START A SLOW DECREASE AS WIND SPEEDS START TO DROP
LATE MON NIGHT. SEAS WILL BE 2 TO 4 FT TUE/TUE NIGHT.

LONG TERM /WEDNESDAY THROUGH THURSDAY/...
AS OF 3 AM SUNDAY...LIGHT NORTHEAST FLOW DEVELOPS EARLY WED AS HIGH
PRESSURE BUILDS IN FROM THE NORTHEAST. SPEEDS START OUT AROUND 10 KT
BUT INCREASE DURING WED AS GRADIENT TIGHTENS. BY THU MORNING
NORTHEAST WINDS WILL BE 15 TO 20 KT WITH A SOLID 20 KT BY THE END OF
THU. PROLONGED AND INCREASING NORTHEAST FLOW WILL BUILD SEAS FROM 3
TO 5 FT WED/WED NIGHT TO 4 TO 7 FT THU/THU NIGHT.

&&

.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.

&&

$$

NEAR TERM...TRA
SHORT TERM...III
LONG TERM...III
AVIATION...43/TRA






AREA FORECAST DISCUSSION

NWS RALEIGH NC

 303 AM EDT SUN APR 28 2013

.SYNOPSIS...
A SLOW MOVING STORM SYSTEM OVER THE MISSISSIPPI VALLEY WILL APPROACH
THE AREA LATE TODAY AND TONIGHT... THEN CROSS THE REGION ON MONDAY.
RAIN IS EXPECTED TO OVERSPREAD THE REGION FROM THE WEST TODAY... AND
CONTINUE TONIGHT INTO MONDAY.

&&

.NEAR TERM /THROUGH SUNDAY NIGHT/...
AS OF 845 PM SATURDAY:

REST OF TONIGHT: THE DE FACTO THEME OF RECENT FORECASTS HAS BEEN TO
SLOW DOWN THE ARRIVAL OF RAIN... AS THIS INCOMING STORM SYSTEM HAS
BEEN PROGRESSING VERY SLOWLY EASTWARD... AND THE MODELS HAVE
CONTINUED TO STEADILY DELAYED PRECIP ARRIVAL FOR SEVERAL RUNS NOW.
THIS THEME MUST BE CONTINUED THIS EVENING... AS THE NEWEST
FINE-SCALE CONVECTION-ALLOWING MODEL RUNS GREATLY HOLD BACK THE
ARRIVAL OF SIGNIFICANT RAIN IN THE WESTERN CWA UNTIL CLOSE TO
DAYBREAK. ONE BROKEN BAND OF WEAKLY FORCED RAIN HAS STREAKED ACROSS
SWRN NC AND THE NC/SC BORDER IN THE LAST SEVERAL HOURS... SUPPORTED
IN PART BY SHEARING MID LEVEL VORTICITY. UPPER DIVERGENCE WILL
WEAKEN OVER NC AS A JET STREAK HEADS OFFSHORE WITH MID LEVEL RIDGING
BUILDING IN TONIGHT AHEAD OF THE INCOMING SLOW-MOVING SHORTWAVE
TROUGH OVER THE MID MISS VALLEY... LEADING TO DISSIPATION OF FORCED
ASCENT OVER NC. THE LOW LEVELS OVER THE WESTERN CWA HAVE MOISTENED
UP QUICKLY EARLY THIS EVENING BUT NOT SO IN THE NORTHEAST CWA... AND
THE RAP AND LOCAL WRF BRING THE SLIGHTLY DRIER AIR NOW OVER NE NC/SE
VA WESTWARD TONIGHT (DUE TO THE ESE SURFACE CIRCULATION AROUND THE
SURFACE HIGH CENTERED OFF DELMARVA)... A REASONABLE TRAJECTORY. WITH
THE WANING FORCING OVER NC... AND WITH THE STRONG SOUTHWESTERLY 850
MB JET THAT IS HELPING TO DRIVE THE CONVECTION OVER AL/N GA/E TN
EXPECTED TO HOLD WELL TO OUR WEST OVERNIGHT (ACCELERATING UP INTO
FAR WRN WV)... WE`RE UNLIKELY TO SEE ENOUGH OF A SURGE IN MOISTURE
OR INCREASE IN LIFT FOR ANYTHING BUT PATCHY VERY LIGHT RAIN OR
SPRINKLES UNTIL CLOSE TO SUNRISE. WILL LEAVE IN PATCHY SPRINKLES IN
THE WEST AND SOUTH FOR MUCH OF THE NIGHT... BUT WILL HOLD OFF THE
HIGHER POPS IN THE WESTERN CWA UNTIL AFTER 5 AM. THE OVERCAST MID
AND HIGH CLOUDS WILL HELP KEEP TEMPS UP OVERNIGHT... BUT ONLY SMALL
ADJUSTMENTS ARE NEEDED... LOWS NEAR 50 NORTHEAST TO MID 50S
SOUTHWEST. -GIH

THROUGH SUNDAY:
RAIN CHANCES WILL SLOWLY BUT STEADILY INCREASE FROM WEST TO EAST
THROUGH THE DAY ON SUNDAY AS THE BLOCKING RIDGE OVER THE EASTERN
SEABOARD SHIFTS OFFSHORE...ALLOWING THE UPPER TROUGH TO FINALLY
PROGRESS EASTWARD INTO THE APPALACHIANS. PWATS INCREASE TO 1.2-1.3"
LATE SUNDAY AFTERNOON THROUGH SUNDAY NIGHT((2 STANDARD DEVIATIONS
ABOVE NORMAL)WITH THE EASTWARD PUSH OF SOUTHERLY 30KT LOW-LEVEL FEED
OF GULF MOISTURE INTO THE AREA. THUS...EXPECT CHANCES FOR RAIN TO
PRIMARILY BE CONFINED WEST OF HWY 1 THROUGH THE EARLY-MID AFTERNOON
BEFORE EVENTUALLY SPREADING EAST OF HWY 1 SUNDAY EVENING/NIGHT.

WIDESPREAD CLOUD COVER AND AREAL COVERAGE OF PRECIP WILL BE THE MAIN
DETERMINING FACTOR ON TEMPERATURES THROUGH THE PERIOD. OVERNIGHT LOWS
IN THE 50S EACH NIGHT. HIGHS SUNDAY...WILL BE VERY CAD
LIKE...ESPECIALLY IF RAINFALL THROUGH THE AFTERNOON IS CONFINED TO
WESTERN PORTIONS OF THE STATE. HIGHS IN THE LOWER 60S WEST TO LOWER
70S EAST.

&&

.SHORT TERM /MONDAY AND MONDAY NIGHT/...
AS OF 255 PM SATURDAY...

WIDESPREAD PRECIP WILL BE ONGOING TO START MONDAY MORNING. THIS
PRECIP WILL BE MAINLY CAUSED BY AN EASTWARD PROGRESSING UPPER
WAVE...ALTHOUGH SOME MODELS ARE ALSO HINTING AT A WEAK SURFACE WAVE
DEVELOPING...WHICH WOULD ALSO ENHANCE THE PRECIP. THE UPPER TROUGH
IS PROGGED TO BE ALMOST DIRECTLY OVERHEAD MONDAY AFTERNOON AND THEN
BE MOVING OFFSHORE BY MONDAY NIGHT. ANY RESIDUAL COOL STABLE CAD
LAYER SHOULD SCOUR OUT THROUGHOUT THE DAY ON MONDAY AS THE SURFACE
HIGH PROGRESSES FURTHER OFFSHORE AND SOUTHERLY FLOW TAKES OVER. AS A
RESULT...HAVE INCREASED TEMPS TO THE MID/UPPER 60S TO THE LOWER 70S.
IN ADDITION...WITH THE WARMER TEMPS AND THE FACT THAT THE UPPER
LEVEL TROUGH SHOULD BE RIGHT OVERHEAD DURING THE HEATING OF THE
DAY...THERE COULD BE SOME SCATTERED THUNDERSTORMS THAT DEVELOP
MONDAY AFTERNOON. AS THE UPPER LEVEL TROUGH AXIS SHIFTS EAST OF THE
REGION MONDAY NIGHT...DRIER AIR ALOFT WILL FILTER IN AND THE PRECIP
COVERAGE SHOULD DECREASE FROM WEST TO EAST MONDAY EVENING/NIGHT.
STORM TOTAL PRECIP (INCLUDING AMOUNTS THAT FALL BEFORE MONDAY) ARE
EXPECTED TO BE BETWEEN 1-2 INCHES. OVERNIGHT LOWS SHOULD GENERALLY
BE IN THE MID 50S.

&&

.LONG TERM /TUESDAY THROUGH SATURDAY/...
AS OF 303 AM SUNDAY...

FINALLY... SOME AGREEMENT WITH THE OPERATIONAL MODELS WITH THE
DEVELOPING BLOCKY MID/UPPER LEVEL FLOW PATTERN EXPECTED TO EVOLVE
THIS WEEK. THE TRANSITION SEASON IS CLIMATOLOGICALLY FAVORABLE FOR
"CUT OFF LOWS" WITH APRIL AND MAY THE PRIME MONTHS. THE FAVORED
LOCATION IS IN THE CENTRAL AND EASTERN UNITED STATES. THIS WEEK WILL
NOT DISAPPOINT WITH REGARDS TO A LARGE "CUT OFF LOW" THAT WILL BE
SLOW TO MOVE ACROSS THE PLAINS. MORE IMPORTANTLY TO OUR WEATHER WILL
BE THE LARGE DEVELOPING RIDGE DOWN THE EASTERN SEABOARD THAT WILL
BLOCK THIS STORM TO OUR WEST FOR THE BULK OF THE WEEK.

A COUPLE OF LARGE UPPER RIDGES ARE FORECAST TO DEVELOP MID TO LATE
WEEK OVER SOUTHEASTERN AND SOUTHWESTERN CANADA. THIS WILL HELP THE
TROUGH DEVELOPING OVER THE CENTRAL PLAINS TO "CUT OFF" LATE THIS
WEEK. DUE TO THE BLOCKING EXPECTED OVER SE CANADA AND THE
STRENGTHENING SURFACE HIGH PRESSURE THAT IS FORECAST TO EXTEND FROM
NEW ENGLAND DOWN THE EASTERN SEABOARD MID TO LATE WEEK... THE "CUT
OFF LOW" OVER THE PLAINS WILL VERY SLOWLY MOVE EAST TOWARD THE OHIO
VALLEY BY NEXT WEEKEND. THE WEATHER ASSOCIATED WITH THIS UPPER LOW
AND THE TRAILING SURFACE COLD FRONT WILL REMAIN WEST OF THE
APPALACHIANS THIS WEEK... WITH THE POTENTIAL FOR THE FRONT TO FALL
APART BEFORE REACHING EAST OF THE MOUNTAINS NEXT WEEKEND.

AS MENTIONED IN THE PREVIOUS DISCUSSION FROM SATURDAY AFTERNOON...
ADJUSTMENTS TOWARD A DRIER FORECAST WILL HAVE TO BE MADE MID TO LATE
WEEK FOR OUR REGION. WE WILL CONTINUE TO TREND THAT WAY WITH ADDED
CONFIDENCE WITH THIS FORECAST. ALSO... TEMPS MID TO LATE WEEK WILL
BE COOLER THAN NORMAL GIVEN THE EXPECTED PROLONGED NORTHEAST FLOW
ASSOCIATED WITH THE LARGE SURFACE HIGH PRESSURE CENTERED TO OUR
NORTH AND NORTHEAST.

SENSIBLE WEATHER... THE DEVELOPING AND DEEPENING NE FLOW ON TUESDAY
SHOULD LEAD TO AMPLE LOW LEVEL MOISTURE TRAPPED UNDER AN INVERSION
ALOFT. VARIABLY TO MOSTLY CLOUDY SKIES SHOULD BECOME OVERCAST LATE
TUESDAY INTO WEDNESDAY. THIS WILL TEMPER DAYTIME TEMPERATURES.
FORECAST SOUNDINGS INDICATE THAT IT MAY BE THURSDAY BEFORE SOME
DRIER AIR WORKS ITS WAY INTO THE AREA FROM THE NORTH. WE WILL KEEP A
SMALL CHANCE OF SHOWERS BOTH TUESDAY AND WEDNESDAY AS MODELS SUGGEST
A SLIGHT UPTICK IN THE CHANCE OF SHOWERS DURING THE AFTERNOON AND
EARLY EVENING HOURS BOTH DAYS. INSTABILITY SHOULD BE LACKING AND
THUNDER IS NOT CURRENTLY EXPECTED. THIS SHOULD BE FOLLOWED BY A DRY
FORECAST FOR THU-FRI. SATURDAY... STILL UP FOR DEBATE BUT THE SLOWER
FORECAST DUE TO BLOCKING IS FAVORED.

TUESDAY AND WEDNESDAY... LOW OVERCAST AT NIGHT WITH MOSTLY CLOUDY
AFTERNOON`S. A CHANCE OF MAINLY AFTERNOON SHOWERS. LOWS IN THE MID
50S TO AROUND 60. HIGHS 68-75 TUESDAY... AND 65-72 WEDNESDAY. PARTLY
SUNNY AND EVEN COOLER THURSDAY AND FRIDAY. LOWS 45-50. HIGHS 65-70.
PARTLY SUNNY SATURDAY. LOWS AROUND 50. HIGHS 70-75.


&&

.AVIATION /06Z SUNDAY THROUGH THURSDAY/...
AS OF 110 AM SUNDAY...

VFR CONDITIONS WITH CEILINGS BETWEEN 5000-10000FT WILL OCCUR
OVERNIGHT THROUGH THE EARLY MORNING HOURS. AN INCREASING LOW LEVEL
SE FLOW WILL ADVECT ADDITIONAL MOISTURE INTO CENTRAL NC WHILE AN
AREA OF LOW PRESSURE LIFTS N-NE ACROSS THE OH VALLEY. THIS WEATHER
SYSTEM WILL BRING AREAS OF RAIN TO THE WESTERN PIEDMONT INCLUDING
KINT AND KGSO BY LATE MORNING. THIS WILL LEAD TO MVFR/IFR CEILINGS
TO THE TRIAD REGION TERMINALS BY MID DAY. THE LEADING EDGE OF THE
RAIN SHIELD WILL CREEP EWD THIS AFTERNOON AND TONIGHT...EVENTUALLY
REACHING KRDU...KRWI AND KFAY LATE THIS AFTERNOON-EARLY EVENING. THE
RAIN WILL CONTINUE TONIGHT INTO MOST OF MONDAY THEN DIMINISH FROM
THE WEST LATE MONDAY AND MONDAY NIGHT.

WHILE THE RAIN WILL END...THE MVFR-IFR CEILINGS WILL PERSIST MONDAY
NIGHT INTO TUESDAY AS MOISTURE WILL REMAIN TRAPPED BELOW A MID LEVEL
INVERSION. A NE FLOW IN THE LOWEST 5000-8000FT OF THE ATMOSPHERE
WILL FEED MOISTURE OFF THE ATLANTIC INTO CENTRAL NC THROUGH EARLY
THURSDAY...MAINTAINING THE LOW CLOUDS AND ASSOCIATED SUB VFR
CEILINGS.  IMPROVING AVIATION CONDITIONS AND A RETURN TO VFR
PARAMETERS EXPECTED BY THURSDAY.

&&

.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.

&&

$$

SYNOPSIS...WSS
NEAR TERM...HARTFIELD/CBL
SHORT TERM...KRR
LONG TERM...BADGETT
AVIATION...WSS









AREA FORECAST DISCUSSION

NWS RALEIGH NC

 110 AM EDT SUN APR 28 2013

.SYNOPSIS...
A SLOW MOVING STORM SYSTEM OVER THE MISSISSIPPI VALLEY WILL APPROACH
THE AREA SUNDAY...AND CROSS THE REGION ON MONDAY. THIS WEATHER
SYSTEM WILL BRING PERIODS OF RAIN TO CENTRAL NC TODAY THROUGH MONDAY
NIGHT.

&&

.NEAR TERM /THROUGH SUNDAY NIGHT/...
AS OF 845 PM SATURDAY:

REST OF TONIGHT: THE DE FACTO THEME OF RECENT FORECASTS HAS BEEN TO
SLOW DOWN THE ARRIVAL OF RAIN... AS THIS INCOMING STORM SYSTEM HAS
BEEN PROGRESSING VERY SLOWLY EASTWARD... AND THE MODELS HAVE
CONTINUED TO STEADILY DELAYED PRECIP ARRIVAL FOR SEVERAL RUNS NOW.
THIS THEME MUST BE CONTINUED THIS EVENING... AS THE NEWEST
FINE-SCALE CONVECTION-ALLOWING MODEL RUNS GREATLY HOLD BACK THE
ARRIVAL OF SIGNIFICANT RAIN IN THE WESTERN CWA UNTIL CLOSE TO
DAYBREAK. ONE BROKEN BAND OF WEAKLY FORCED RAIN HAS STREAKED ACROSS
SWRN NC AND THE NC/SC BORDER IN THE LAST SEVERAL HOURS... SUPPORTED
IN PART BY SHEARING MID LEVEL VORTICITY. UPPER DIVERGENCE WILL
WEAKEN OVER NC AS A JET STREAK HEADS OFFSHORE WITH MID LEVEL RIDGING
BUILDING IN TONIGHT AHEAD OF THE INCOMING SLOW-MOVING SHORTWAVE
TROUGH OVER THE MID MISS VALLEY... LEADING TO DISSIPATION OF FORCED
ASCENT OVER NC. THE LOW LEVELS OVER THE WESTERN CWA HAVE MOISTENED
UP QUICKLY EARLY THIS EVENING BUT NOT SO IN THE NORTHEAST CWA... AND
THE RAP AND LOCAL WRF BRING THE SLIGHTLY DRIER AIR NOW OVER NE NC/SE
VA WESTWARD TONIGHT (DUE TO THE ESE SURFACE CIRCULATION AROUND THE
SURFACE HIGH CENTERED OFF DELMARVA)... A REASONABLE TRAJECTORY. WITH
THE WANING FORCING OVER NC... AND WITH THE STRONG SOUTHWESTERLY 850
MB JET THAT IS HELPING TO DRIVE THE CONVECTION OVER AL/N GA/E TN
EXPECTED TO HOLD WELL TO OUR WEST OVERNIGHT (ACCELERATING UP INTO
FAR WRN WV)... WE`RE UNLIKELY TO SEE ENOUGH OF A SURGE IN MOISTURE
OR INCREASE IN LIFT FOR ANYTHING BUT PATCHY VERY LIGHT RAIN OR
SPRINKLES UNTIL CLOSE TO SUNRISE. WILL LEAVE IN PATCHY SPRINKLES IN
THE WEST AND SOUTH FOR MUCH OF THE NIGHT... BUT WILL HOLD OFF THE
HIGHER POPS IN THE WESTERN CWA UNTIL AFTER 5 AM. THE OVERCAST MID
AND HIGH CLOUDS WILL HELP KEEP TEMPS UP OVERNIGHT... BUT ONLY SMALL
ADJUSTMENTS ARE NEEDED... LOWS NEAR 50 NORTHEAST TO MID 50S
SOUTHWEST. -GIH

THROUGH SUNDAY:
RAIN CHANCES WILL SLOWLY BUT STEADILY INCREASE FROM WEST TO EAST
THROUGH THE DAY ON SUNDAY AS THE BLOCKING RIDGE OVER THE EASTERN
SEABOARD SHIFTS OFFSHORE...ALLOWING THE UPPER TROUGH TO FINALLY
PROGRESS EASTWARD INTO THE APPALACHIANS. PWATS INCREASE TO 1.2-1.3"
LATE SUNDAY AFTERNOON THROUGH SUNDAY NIGHT((2 STANDARD DEVIATIONS
ABOVE NORMAL)WITH THE EASTWARD PUSH OF SOUTHERLY 30KT LOW-LEVEL FEED
OF GULF MOISTURE INTO THE AREA. THUS...EXPECT CHANCES FOR RAIN TO
PRIMARILY BE CONFINED WEST OF HWY 1 THROUGH THE EARLY-MID AFTERNOON
BEFORE EVENTUALLY SPREADING EAST OF HWY 1 SUNDAY EVENING/NIGHT.

WIDESPREAD CLOUD COVER AND AREAL COVERAGE OF PRECIP WILL BE THE MAIN
DETERMINING FACTOR ON TEMPERATURES THROUGH THE PERIOD. OVERNIGHT LOWS
IN THE 50S EACH NIGHT. HIGHS SUNDAY...WILL BE VERY CAD
LIKE...ESPECIALLY IF RAINFALL THROUGH THE AFTERNOON IS CONFINED TO
WESTERN PORTIONS OF THE STATE. HIGHS IN THE LOWER 60S WEST TO LOWER
70S EAST.

&&

.SHORT TERM /MONDAY AND MONDAY NIGHT/...
AS OF 255 PM SATURDAY...

WIDESPREAD PRECIP WILL BE ONGOING TO START MONDAY MORNING. THIS
PRECIP WILL BE MAINLY CAUSED BY AN EASTWARD PROGRESSING UPPER
WAVE...ALTHOUGH SOME MODELS ARE ALSO HINTING AT A WEAK SURFACE WAVE
DEVELOPING...WHICH WOULD ALSO ENHANCE THE PRECIP. THE UPPER TROUGH
IS PROGGED TO BE ALMOST DIRECTLY OVERHEAD MONDAY AFTERNOON AND THEN
BE MOVING OFFSHORE BY MONDAY NIGHT. ANY RESIDUAL COOL STABLE CAD
LAYER SHOULD SCOUR OUT THROUGHOUT THE DAY ON MONDAY AS THE SURFACE
HIGH PROGRESSES FURTHER OFFSHORE AND SOUTHERLY FLOW TAKES OVER. AS A
RESULT...HAVE INCREASED TEMPS TO THE MID/UPPER 60S TO THE LOWER 70S.
IN ADDITION...WITH THE WARMER TEMPS AND THE FACT THAT THE UPPER
LEVEL TROUGH SHOULD BE RIGHT OVERHEAD DURING THE HEATING OF THE
DAY...THERE COULD BE SOME SCATTERED THUNDERSTORMS THAT DEVELOP
MONDAY AFTERNOON. AS THE UPPER LEVEL TROUGH AXIS SHIFTS EAST OF THE
REGION MONDAY NIGHT...DRIER AIR ALOFT WILL FILTER IN AND THE PRECIP
COVERAGE SHOULD DECREASE FROM WEST TO EAST MONDAY EVENING/NIGHT.
STORM TOTAL PRECIP (INCLUDING AMOUNTS THAT FALL BEFORE MONDAY) ARE
EXPECTED TO BE BETWEEN 1-2 INCHES. OVERNIGHT LOWS SHOULD GENERALLY
BE IN THE MID 50S.

&&

.LONG TERM /TUESDAY THROUGH SATURDAY/...
AS OF 255 PM SATURDAY...

STRENGTHENING SURFACE HIGH PRESSURE OVER NEW ENGLAND WILL BEGIN TO
BUILD DOWN INTO CENTRAL NC AND THEN LIKELY PERSIST THROUGH THE END
OF THE LONG TERM PERIOD. AS A RESULT...SURFACE WINDS SHOULD BE OUT
OF THE NORTHEAST FOR MUCH OF THE PERIOD AND THE AIR MASS SHOULD BE
RELATIVELY STABLE. IN ADDITION...MODELS NOW SHOW THE MID LEVEL RIDGE
GRADUALLY BUILDING DOWN TOWARDS THE MID ATLANTIC...WHICH HAD BEEN
FORECAST TO BE CENTERED OVER NORTHERN NEW ENGLAND. ALL OF THIS
SHOULD RESULT IN LESS IN THE WAY OF PRECIP COVERAGE...ESPECIALLY BY
THE MIDDLE TO END OF THE WORK WEEK WHEN IT VERY WELL COULD END UP
BEING MOSTLY DRY. TEMPS SHOULD GENERALLY BE IN THE LOW/MID 70S...
STILL SLIGHTLY BELOW NORMAL DUE TO THE COOL MOIST NORTHEASTERLY
FLOW. THERE IS STILL QUITE A BIT OF UNCERTAINTY WITH REGARDS TO OUR
NEXT SYSTEM...BUT THE BUILDING RIDGE OVER THE EAST COAST MAY HOLD IT
WEST OF THE REGION (WHILE A SOUTHERN STREAM SYSTEM IS SHUNTED TO OUR
SOUTH) UNTIL THE VERY END (OR JUST BEYOND) THE CURRENT FORECAST
PERIOD.

&&

.AVIATION /06Z SUNDAY THROUGH THURSDAY/...
AS OF 110 AM SUNDAY...

VFR CONDITIONS WITH CEILINGS BETWEEN 5000-10000FT WILL OCCUR
OVERNIGHT THROUGH THE EARLY MORNING HOURS. AN INCREASING LOW LEVEL
SE FLOW WILL ADVECT ADDITIONAL MOISTURE INTO CENTRAL NC WHILE AN
AREA OF LOW PRESSURE LIFTS N-NE ACROSS THE OH VALLEY. THIS WEATHER
SYSTEM WILL BRING AREAS OF RAIN TO THE WESTERN PIEDMONT INCLUDING
KINT AND KGSO BY LATE MORNING. THIS WILL LEAD TO MVFR/IFR CEILINGS
TO THE TRIAD REGION TERMINALS BY MID DAY. THE LEADING EDGE OF THE
RAIN SHIELD WILL CREEP EWD THIS AFTERNOON AND TONIGHT...EVENTUALLY
REACHING KRDU...KRWI AND KFAY LATE THIS AFTERNOON-EARLY EVENING. THE
RAIN WILL CONTINUE TONIGHT INTO MOST OF MONDAY THEN DIMINISH FROM
THE WEST LATE MONDAY AND MONDAY NIGHT.

WHILE THE RAIN WILL END...THE MVFR-IFR CEILINGS WILL PERSIST MONDAY
NIGHT INTO TUESDAY AS MOISTURE WILL REMAIN TRAPPED BELOW A MID LEVEL
INVERSION. A NE FLOW IN THE LOWEST 5000-8000FT OF THE ATMOSPHERE
WILL FEED MOISTURE OFF THE ATLANTIC INTO CENTRAL NC THROUGH EARLY
THURSDAY...MAINTAINING THE LOW CLOUDS AND ASSOCIATED SUB VFR
CEILINGS.  IMPROVING AVIATION CONDITIONS AND A RETURN TO VFR
PARAMETERS EXPECTED BY THURSDAY.

&&

.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.

&&

$$

SYNOPSIS...WSS
NEAR TERM...HARTFIELD/CBL
SHORT TERM...KRR
LONG TERM...KRR
AVIATION...WSS






AREA FORECAST DISCUSSION

NWS GRAND FORKS ND

 944 PM CDT MON APR 29 2013

.UPDATE...
ISSUED AT 945 PM CDT MON APR 29 2013

OTHER THAN TIMING THE POPS A BIT BETTER THIS EVENING...NO CHANGES
AT ALL TO PREVIOUS UPDATE THINKING. WE DID ADD ADDITIONAL
INFORMATION INTO THE HYDRO PORTION OF THIS AFD.

UPDATE ISSUED AT 645 PM CDT MON APR 29 2013

THE MAIN CHALLENGE OVERNIGHT WILL BE RAIN SHOWER/THUNDER CHANCES
AND QPF AMOUNTS. A BAND OF ORGANIZED SHOWERS CONTINUES TO MOVE
INTO THE DVL BASIN INTO NE ND...WITH PERHAPS UP TO ONE TENTH OF AN
INCH SO FAR. MODELS ARE IN GOOD AGREEMENT WITH A STRONG
SHORTWAVE...COUPLED JET AND INCREASING LLJ MOVING INTO THE AREA
OVERNIGHT. THE BEST LARGE SCALE FOCUS FOR HEAVIER RAIN SHOWERS
WILL BE FROM AROUND GRIGGS COUNTY THROUGH GRAND FORKS COUNTY INTO
ROSEAU COUNTY. THE LATEST RAP GUIDANCE IS EVEN A BIT FURTHER
NORTH. THERE WILL BE SOME ELEVATED INSTABILITY AFTER 06Z MAINLY IN
THE SOUTHERN 1/3 OF THE AREA...WITH 850MB JET INCREASING TO 50KT
AND 850MB CAPE AROUND 400 J/KG. THEREFORE...CAN/T RULE OUT SOME
SMALL HAIL IN THE SOUTH LATER TONIGHT ONCE SHORTWAVE INTERACTS
WITH LLJ AND MID LEVEL FGEN. WILL INCREASE POPS INITIALLY IN THE
DVL BASIN THIS EVENING...WITH THE REST OF THE WX/POPS LOOKING GOOD
WITH SHOWERS AND ISOLATED THUNDER OVERNIGHT. QPF AMOUNTS SHOULD
RANGE FROM AROUND 0.50 TO 1 INCH IN THE HEAVIER RAIN BAND...WITH
LIGHTER AMOUNTS TO THE SOUTH.

IT LOOKS WINDY ON TUE BEHIND A COLD FRONT...WITH 40KT TO MIX IN A
DEVELOPING ADIABATIC LAYER UP TO 800MB. THEREFORE...A WIND
ADVISORY MAY BE NEEDED TOMORROW ALONG AND WEST OF THE VALLEY...AND
WILL INCREASE WINDS INTO THE 25 TO 35 MPH RANGE WITH GUSTS TO 40
MPH POSSIBLE.

&&

.SHORT TERM...(THIS EVENING THROUGH TUESDAY NIGHT)
ISSUED AT 336 PM CDT MON APR 29 2013

MAIN FORECAST CHALLENGES WILL BE PCPN CHANCES AND AMOUNTS TONIGHT
AND TEMPS THE NEXT FEW DAYS. MODELS GENERALLY REMAIN IN GOOD
AGREEMENT WITH THE PCPN EVENT TONIGHT INTO EARLY TUESDAY SO WILL
NOT HAVE TO DEVIATE MUCH FROM FORECAST CONTINUITY. MID AND HIGH
LEVEL CLOUDS CONTINUE TO STREAM INTO THE FA AND IT SHOULD BECOME
MOSTLY CLOUDY IN ALL AREAS TONIGHT. KMVX WSR88D SHOWS A BAND OF
LIGHT PCPN FROM LANGDON TO CARRINGTON. LIKE YESTERDAY THERE IS A
SUBSTANTIAL DRY LAYER BELOW THE CLOUDS SO NOT SEEING MUCH PCPN AT
THE SFC. MAINLY JUST SPRINKLES AND LIGHT SHOWERS. NO INSTABILITY
OVER THE FA YET SO WILL JUST KEEP LIGHT SHOWERS IN THE FORECAST
INTO THE EARLY EVENING. MORE SUBSTANTIAL PCPN EVENT WILL PROBABLY
NOT GET UNDERWAY UNTIL MID TO LATE EVENING. WATER VAPOR IMAGERY
SHOWS THE TROUGH OVER THE WESTERN UNITED STATES WITH A STRONG
UPPER JET AROUND THE SOUTHERN PERIPHERY OF THE TROUGH. THIS UPPER
JET WILL CONTINUE TO POKE INTO OUR FA TONIGHT AND PROVIDE GOOD
LIFT FOR THE PCPN EVENT. SFC INSTABILITY IS ALL AROUND NORTHERN
MT WHERE THERE ARE SOME LIGHTNING STRIKES. THE BETTER
ORGANIZATION FOR OUR EVENT TONIGHT WILL PROBABLY COME IN THE FORM
OF THE LOW LEVEL JET THIS EVENING AND OVERNIGHT WHICH WILL BRING
SOME INSTABILITY AS WELL. WILL LEAVE THE ISOLATED MENTION OF
THUNDER BY MID EVENING AND EXTEND IT EAST-NE OVERNIGHT. BEST AREA
FOR PCPN STILL APPEARS TO BE FROM KJMS TO KGFK UP TOWARDS BDE WITH
AMOUNTS GENERALLY AROUND A HALF AN INCH...COULD BE SOME SPOTS
CLOSER TO AN INCH WITH ANY STRONGER CELLS.

MOST OF THE PCPN SHOULD BE OVER THE NORTH AND NORTHEAST ON TUE
WITH DRY CONDITIONS SPREADING IN ELSEWHERE. LOOKS LIKE A FAIRLY
BREEZY DAY WITH HIGHS COOLER THAN TODAY. WILL END ALL PCPN BY TUE
NIGHT WITH TEMPS GENERALLY FALLING BELOW 32F.

.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 336 PM CDT MON APR 29 2013

FOR WED INTO THU THE WESTERN TROUGH DIGS INTO THE CENTRAL UNITED
STATES WITH THE MODELS SHOWING A CUTOFF LOW DEVELOPING OVER THE
CENTRAL PLAINS. THIS WILL LEAD TO COOLER WEATHER BUT WILL KEEP IT
DRY. NIGHTTIME LOWS SHOULD DROP BELOW 32F WHICH SHOULD SLOW DOWN
THE WATER MOVEMENT.

THU NIGHT TO MON...PRIMARY CHALLENGES THROUGH THE LONG TERM WILL
BE EFFECTS FROM DEVELOPING UPPER LOW OVER CENTRAL PLAINS AND
EVENTUAL TRACK OF FEATURE. MODELS INITIALLY IN GOOD AGREEMENT IN
DEVELOPING CLOSED LOW OVER CENTRAL/SOUTHERN PLAINS. MODELS THEN
SPLIT ON TRACK OF THIS FEATURE THROUGH THE LATER PART OF THE LONG
TERM. ECMWF LIFTS UPPER LOW DUE NORTH BRINGING BETTER CHANCES OF
RAIN TO THE REGION THIS WEEKEND WHILE THE GFS/GEM WITH FARTHER
SOUTH SOLUTION KEEP THE FA MAINLY DRY. WILL MAINTAIN CURRENT POPS
UNTIL WE GET A LITTLE BETTER MODEL AGREEMENT. TEMPERATURES THROUGH
BRUNT OF PERIOD WILL RANGE BLO AVERAGE WITH SOME RECOVERY POSSIBLE
LATE.

&&

.HYDROLOGY...
ISSUED AT 945 PM CDT MON APR 29 2013

THE CREST WAVE ON THE RED RIVER IS NEAR HICKSON MONDAY NIGHT...AND
WILL REACH FARGO BY WEDNESDAY. BASED ON UPSTREAM FLOWS...INCLUDING
THE OBSERVED CREST ON THE WILD RICE RIVER AT ABERCROMBIE...THE PEAK
FLOW AT FARGO IS EXPECTED TO BE AROUND 19000 CFS. THAT WILL RESULT
IN A CREST AROUND 35.5 FEET AT FARGO.

THE MAIN POINT OF FOCUS THE NEXT FEW DAYS WILL BE OVER NORTHEASTERN
NORTH DAKOTA IN THE PEMBINA...FOREST RIVER...AND PARK RIVER BASINS.
THE PEMBINA RIVER IN PARTICULAR WILL CONTINUE RECEIVING SOME RUNOFF
FROM LOCAL SNOWMELT...BUT WILL ALSO PICK UP ADDITIONAL FLOW COMING
OUT OF SOUTHERN CANADA IN THE COMING DAYS. WE STILL EXPECT THE RIVER
LEVELS TO REACH THE POINT WHERE BREAKOUT FLOW OCCURS DOWNSTREAM OF
WALHALLA TOWARD NECHE...INCREASING OVERLAND FLOODING IN THOSE AREAS.

RAINFALL MONDAY NIGHT IS EXPECTED TO TOTAL BETWEEN A QUARTER AND A
HALF INCH...WITH LOCALLY HIGHER AMOUNTS NEAR AN INCH...ESPECIALLY IN
THE NORTHERN END OF THE RED RIVER VALLEY. THIS RAIN IS FACTORED INTO
THE RIVER FORECASTS ALREADY...BUT IF LOCALLY HIGHER AMOUNTS OCCUR IT
COULD STILL HAVE AN IMPACT ON SMALLER RIVERS AND TRIBUTARIES. IT MAY
ALSO INCREASE OVERLAND FLOODING IN SOME AREAS.

AS FAR AS OVERLAND FLOODING GOES...SEVERAL WARNINGS FOR THAT REMAIN
IN EFFECT UNTIL 600 PM CDT TUESDAY. ONCE THE RAIN EVENT FROM MONDAY
NIGHT IS OVER WITH AND THE IMPACTS ARE ASSESSED...WE WILL PROBABLY
BE ABLE TO LET SOME OF THOSE WARNINGS EXPIRE ON SCHEDULE TUESDAY. WE
MAY ALSO BE ABLE TO LET THE REST OF THE FLOOD WATCH OVER THE DEVILS
LAKE BASIN EXPIRE TUESDAY AFTERNOON AS REPORTS FROM THAT AREA HAVE
NOT INDICATED MUCH IN THE WAY OF PROBLEMS WITH OVERLAND FLOODING.

FINALLY...NOTE THAT STRONG WEST WINDS ARE EXPECTED ON TUESDAY...AND
THAT COULD PRODUCE SOME WAVE ACTION ON FLOODED FIELDS AND RIVERS.

&&

.FGF WATCHES/WARNINGS/ADVISORIES...
ND...FLOOD WATCH THROUGH TUESDAY AFTERNOON FOR NDZ014-015-024-026.

MN...NONE.
&&

$$

UPDATE...DK
SHORT TERM...GODON
LONG TERM...VOELKER
HYDROLOGY...CS







AREA FORECAST DISCUSSION

NWS GRAND FORKS ND

 646 PM CDT MON APR 29 2013

.UPDATE...
ISSUED AT 645 PM CDT MON APR 29 2013

THE MAIN CHALLENGE OVERNIGHT WILL BE RAIN SHOWER/THUNDER CHANCES
AND QPF AMOUNTS. A BAND OF ORGANIZED SHOWERS CONTINUES TO MOVE
INTO THE DVL BASIN INTO NE ND...WITH PERHAPS UP TO ONE TENTH OF AN
INCH SO FAR. MODELS ARE IN GOOD AGREEMENT WITH A STRONG
SHORTWAVE...COUPLED JET AND INCREASING LLJ MOVING INTO THE AREA
OVERNIGHT. THE BEST LARGE SCALE FOCUS FOR HEAVIER RAIN SHOWERS
WILL BE FROM AROUND GRIGGS COUNTY THROUGH GRAND FORKS COUNTY INTO
ROSEAU COUNTY. THE LATEST RAP GUIDANCE IS EVEN A BIT FURTHER
NORTH. THERE WILL BE SOME ELEVATED INSTABILITY AFTER 06Z MAINLY IN
THE SOUTHERN 1/3 OF THE AREA...WITH 850MB JET INCREASING TO 50KT
AND 850MB CAPE AROUND 400 J/KG. THEREFORE...CAN/T RULE OUT SOME
SMALL HAIL IN THE SOUTH LATER TONIGHT ONCE SHORTWAVE INTERACTS
WITH LLJ AND MID LEVEL FGEN. WILL INCREASE POPS INITIALLY IN THE
DVL BASIN THIS EVENING...WITH THE REST OF THE WX/POPS LOOKING GOOD
WITH SHOWERS AND ISOLATED THUNDER OVERNIGHT. QPF AMOUNTS SHOULD
RANGE FROM AROUND 0.50 TO 1 INCH IN THE HEAVIER RAIN BAND...WITH
LIGHTER AMOUNTS TO THE SOUTH.

IT LOOKS WINDY ON TUE BEHIND A COLD FRONT...WITH 40KT TO MIX IN A
DEVELOPING ADIABATIC LAYER UP TO 800MB. THEREFORE...A WIND
ADVISORY MAY BE NEEDED TOMORROW ALONG AND WEST OF THE VALLEY...AND
WILL INCREASE WINDS INTO THE 25 TO 35 MPH RANGE WITH GUSTS TO 40
MPH POSSIBLE.

&&

.SHORT TERM...(THIS EVENING THROUGH TUESDAY NIGHT)
ISSUED AT 336 PM CDT MON APR 29 2013

MAIN FORECAST CHALLENGES WILL BE PCPN CHANCES AND AMOUNTS TONIGHT
AND TEMPS THE NEXT FEW DAYS. MODELS GENERALLY REMAIN IN GOOD
AGREEMENT WITH THE PCPN EVENT TONIGHT INTO EARLY TUESDAY SO WILL
NOT HAVE TO DEVIATE MUCH FROM FORECAST CONTINUITY. MID AND HIGH
LEVEL CLOUDS CONTINUE TO STREAM INTO THE FA AND IT SHOULD BECOME
MOSTLY CLOUDY IN ALL AREAS TONIGHT. KMVX WSR88D SHOWS A BAND OF
LIGHT PCPN FROM LANGDON TO CARRINGTON. LIKE YESTERDAY THERE IS A
SUBSTANTIAL DRY LAYER BELOW THE CLOUDS SO NOT SEEING MUCH PCPN AT
THE SFC. MAINLY JUST SPRINKLES AND LIGHT SHOWERS. NO INSTABILITY
OVER THE FA YET SO WILL JUST KEEP LIGHT SHOWERS IN THE FORECAST
INTO THE EARLY EVENING. MORE SUBSTANTIAL PCPN EVENT WILL PROBABLY
NOT GET UNDERWAY UNTIL MID TO LATE EVENING. WATER VAPOR IMAGERY
SHOWS THE TROUGH OVER THE WESTERN UNITED STATES WITH A STRONG
UPPER JET AROUND THE SOUTHERN PERIPHERY OF THE TROUGH. THIS UPPER
JET WILL CONTINUE TO POKE INTO OUR FA TONIGHT AND PROVIDE GOOD
LIFT FOR THE PCPN EVENT. SFC INSTABILITY IS ALL AROUND NORTHERN
MT WHERE THERE ARE SOME LIGHTNING STRIKES. THE BETTER
ORGANIZATION FOR OUR EVENT TONIGHT WILL PROBABLY COME IN THE FORM
OF THE LOW LEVEL JET THIS EVENING AND OVERNIGHT WHICH WILL BRING
SOME INSTABILITY AS WELL. WILL LEAVE THE ISOLATED MENTION OF
THUNDER BY MID EVENING AND EXTEND IT EAST-NE OVERNIGHT. BEST AREA
FOR PCPN STILL APPEARS TO BE FROM KJMS TO KGFK UP TOWARDS BDE WITH
AMOUNTS GENERALLY AROUND A HALF AN INCH...COULD BE SOME SPOTS
CLOSER TO AN INCH WITH ANY STRONGER CELLS.

MOST OF THE PCPN SHOULD BE OVER THE NORTH AND NORTHEAST ON TUE
WITH DRY CONDITIONS SPREADING IN ELSEWHERE. LOOKS LIKE A FAIRLY
BREEZY DAY WITH HIGHS COOLER THAN TODAY. WILL END ALL PCPN BY TUE
NIGHT WITH TEMPS GENERALLY FALLING BELOW 32F.

.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 336 PM CDT MON APR 29 2013

FOR WED INTO THU THE WESTERN TROUGH DIGS INTO THE CENTRAL UNITED
STATES WITH THE MODELS SHOWING A CUTOFF LOW DEVELOPING OVER THE
CENTRAL PLAINS. THIS WILL LEAD TO COOLER WEATHER BUT WILL KEEP IT
DRY. NIGHTTIME LOWS SHOULD DROP BELOW 32F WHICH SHOULD SLOW DOWN
THE WATER MOVEMENT.

THU NIGHT TO MON...PRIMARY CHALLENGES THROUGH THE LONG TERM WILL
BE EFFECTS FROM DEVELOPING UPPER LOW OVER CENTRAL PLAINS AND
EVENTUAL TRACK OF FEATURE. MODELS INITIALLY IN GOOD AGREEMENT IN
DEVELOPING CLOSED LOW OVER CENTRAL/SOUTHERN PLAINS. MODELS THEN
SPLIT ON TRACK OF THIS FEATURE THROUGH THE LATER PART OF THE LONG
TERM. ECMWF LIFTS UPPER LOW DUE NORTH BRINGING BETTER CHANCES OF
RAIN TO THE REGION THIS WEEKEND WHILE THE GFS/GEM WITH FARTHER
SOUTH SOLUTION KEEP THE FA MAINLY DRY. WILL MAINTAIN CURRENT POPS
UNTIL WE GET A LITTLE BETTER MODEL AGREEMENT. TEMPERATURES THROUGH
BRUNT OF PERIOD WILL RANGE BLO AVERAGE WITH SOME RECOVERY POSSIBLE
LATE.

&&

.HYDROLOGY...
ISSUED AT 1251 PM CDT MON APR 29 2013

AS FOR THE FLOOD WATCH MADE MULTIPLE CALLS TO COUNTIES IN MN AND
ND. PER THE MN CALLS IT SEEMS LIKE THE MELTING SNOW IS NOT CAUSING
ANY PROBLEMS FOR THE REMAINING WATCH COUNTIES. FROM KTVF UP THRU
THE LAKE OF THE WOODS LITTLE SNOW REMAINS AND COUNTIES REPORT A
HALF AN INCH OF RAIN WOULD ACTUALLY BE NICE. FOR THE WEST CENTRAL
MN COUNTIES OF OTTER TAIL/WADENA/BECKER...THE SNOW IS SINKING IN
AND NO PROBLEMS ARE REPORTED. WILL ALSO DROP GRIGGS COUNTY FROM
THE WATCH AROUND THE KDVL REGION AS SATELLITE SHOWS LITTLE SNOW
REMAINING THERE.

LIGHT TO MODERATE RAIN WILL SPREAD ACROSS THE AREA TONIGHT...HOWEVER
AT THE CURRENT TIME...IT IS NOT EXPECTED TO HAVE A SIGNIFICANT
IMPACT ON RIVERS FORECASTS. IF THUNDERSTORMS DEVELOP AND PERSIST
OVER ANY AREA...THEY COULD PRODUCE AN INCH OF RAIN OR PERHAPS A
BIT MORE IN A SHORT TIME. THE FAVORED AREA FOR THIS WOULD BE IN
NORTHEAST NORTH DAKOTA INTO NW MN. THE BIGGEST IMPACT WOULD BE TO
SMALLER RIVERS AND TRIBUTARIES OF THE RED RIVER.

STRONG WESTERLY WINDS WILL DEVELOP ON TUESDAY...AND THIS COULD
PRODUCE SOME WAVE ACTION ON LARGER BODIES OF OVERLAND FLOODING. A
SPS WAS ISSUED TO HIGHLIGHT THIS THREAT.

THE WILD RICE AND RED LAKE RIVERS BOTH APPEAR TO HAVE CRESTED
LOWER THAN EXPECTED...THUS FORECAST CRESTS FOR FARGO AND GRAND
FORKS ARE TRENDING LOWER THAN PREVIOUSLY THOUGHT. BALD HILL DAM
WILL HAVE RELEASES LATER IN THE WEEK...BUT RIVER LEVELS DOWNSTREAM
WILL NOT RISE TO FLOOD LEVEL. OVERLAND FLOODING WILL CONTINUE IN
THE DEVILS LAKE BASIN AND FORESTED AREAS AS SOLAR HEATING ERODES
WHAT LITTLE SNOWPACK REMAINS. TONIGHTS RAINFALL WILL ALSO HAVE A
SMALL CONTRIBUTION TO THE OVERLAND FLOODING. SEE SPECIFIC WATCHES
AND WARNINGS FOR MORE DETAILS.

&&

.FGF WATCHES/WARNINGS/ADVISORIES...
ND...FLOOD WATCH THROUGH TUESDAY AFTERNOON FOR NDZ014-015-024-026.

MN...NONE.
&&

$$

UPDATE...DK
SHORT TERM...GODON
LONG TERM...VOELKER
HYDROLOGY...SPEICHER/DK








AREA FORECAST DISCUSSION

NWS BISMARCK ND

 117 PM CDT SUN APR 28 2013

.UPDATE...
ISSUED AT 110 PM CDT SUN APR 28 2013

SOMEWHAT DRIER AIR IS WORKING INTO THE NORTHWEST THIS
AFTERNOON...LEADING TO SOME INCREASED FIRE WEATHER CONCERNS. SEE
DISCUSSION BELOW. OVERLAND FLOODING CONTINUES NORTH...INTO THE
JAMES RIVER VALLEY...ALONG WITH CONTINUED RISES OVER MUCH OF THE
SOURIS RIVER VALLEY. UPDATED FORECASTS HAVE BEEN ISSUED...ANOTHER
UPDATE OUT SHORTLY FOR THE DES LACS RIVER NEAR FOXHOLM...NOW
EXPECTED TO CREST ABOVE MAJOR FLOOD STAGE.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 257 AM CDT SUN APR 28 2013

THE MAIN FORECAST ISSUES FOR THE SHORT TERM PERIOD INCLUDE HYDRO
AND FIRE WEATHER ISSUES WHICH ARE OUTLINED BELOW.

A COLD FRONT IS CURRENTLY PUSHING SOUTHEAST OVER NORTH DAKOTA FROM
SOUTHERN CANADA EARLY THIS MORNING. AHEAD OF THE COLD
FRONT...TEMPERATURES HAVE REMAINED WELL ABOVE FREEZING THIS
MORNING...WITH TEMPERATURES MOSTLY IN THE LOWER 50S WEST TO THE
UPPER 40S EAST. THIS HAS ALLOWED FOR CONTINUED MELTING OF THE SNOW
PACK ACROSS NORTH DAKOTA. FOLLOWING THE COLD FRONTAL
PASSAGE...EXPECT COOLER AFTERNOON HIGH TEMPERATURES AS A COOLER
AIRMASS MOVES SOUTH AND OVER THE REGION. AFTERNOON HIGHS WILL
RANGE FROM THE LOW TO MID 50S ACROSS THE NORTH TO THE LOWER 70S
FAR SOUTH CENTRAL. FOR TONIGHT...TEMPERATURES WILL CONTINUE TO BE
ABOVE FREEZING ALLOWING FOR THE MELT TO CONTINUE...WITH THE EXCEPTION OF
THE TURTLE MOUNTAIN REGION WHERE TEMPERATURES MAY DROP TO NEAR 32
DEGREES.

IN REGARDS TO PRECIPITATION CHANCES...PRECIPITATION IS UNLIKELY
DURING THE SHORT TERM PERIOD. THERE HAVE BEEN SOME LIGHT RETURNS
SHOWING UP ON THE RADAR THIS MORNING...BUT WITH DEWPOINT
DEPRESSIONS ON THE ORDER OF 10 TO 20 DEGREES...NOTHING IS REACHING
THE GROUND AND THUS HAVE LEFT POPS LOW. HAVE ALSO ELIMINATED SLIGHT
CHANCE POPS ACROSS THE SOURIS RIVER BASIN BETWEEN 12Z AND
18Z...LATEST 00Z MODEL GUIDANCE AND 07Z RAP RUN KEEPS THE AREA DRY
AS OPPOSED TO THE 12Z ECMWF WHICH HAD SOME LIGHT PRECIP OVER THE
JAMES AND SOURIS RIVER VALLEY.

.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 257 AM CDT SUN APR 28 2013

THE MAIN CONCERNS IN THE EXTENDED ARE RAINFALL ACROSS THE JAMES
RIVER BASIN ON MONDAY AFTERNOON THROUGH MONDAY NIGHT. THIS IS
ASSOCIATED WITH A COMPLEX FRONTAL SYSTEM MOVING ACROSS THE REGION
MONDAY AFTERNOON AND NIGHT. BOTH GFS AND NAM KEEP SOME
INSTABILITY AHEAD OF THE COLD FRONT...AND THIS SHOULD SUPPORT
SCATTERED THUNDERSTORMS. MODELS HAVE BEEN CONSISTENTLY PAINTING
SOME LIGHT TO MODERATE QPF ALONG THE FRONT AS IT MOVES INTO THE
JAMES RIVER VALLEY...AND KEPT THIS CURRENT THINKING GOING THIS
FORECAST PERIOD. AT THIS TIME LOOKS LIKE BETTER THEN A HALF INCH
BUT LESS THAN ONE INCH FOR THE 24 HOUR PERIOD FROM MONDAY AND
MONDAY NIGHT. AT THIS TIME THE SNOW MELT RUNOFF IS NOT AS CRITICAL
ALONG THE JAMES RIVER VALLEY...AND THIS AMOUNT OF QPF WILL LIKELY
BE ABSORBED IN THE SOILS AFTER SEVERAL DAYS OF TEMPERATURES IN
THE 60S AND 70S.

INTERESTING WEATHER PATTERN DEVELOPING AS QUITE AN ANOMALOUS UPPER
LOW DEVELOPS OVER THE CENTRAL PLAINS BY THE END OF THE WEEK.
VARIOUS SCENARIOS HAVE THIS UPPER LOW RETROGRADES AND SPREAD LIGHT
PRECIPITATION INTO NORTHERN PLAINS BY THE END OF THE WEEK. THIS
COULD BE A MIX OF RAIN AND SNOW BY THEN.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 110 PM CDT SUN APR 28 2013

VFR CONDITIONS THROUGH THE TAF PERIOD. EXPECT A BRISK NW WIND
GUSTING OVER 20 KTS...DIMINISHING THIS AFTERNOON...BEFORE
INCREASING AGAIN OUT OF THE SOUTHWEST OVERNIGHT INTO MONDAY MORNING.

&&

.FIRE WEATHER...
ISSUED AT 257 AM CDT SUN APR 28 2013

FIRE WEATHER CONDITIONS WILL NOT BE AS SEVERE WITH COOLER TEMPS
AND HIGHER RELATIVE HUMIDITY IN THE UPPER 20S AND 30S.
HOWEVER...THERE WILL BE A FEW HOURS BETWEEN 18Z TO 21Z WHERE THERE
WILL BE MARGINAL RED FLAG CONDITIONS FOR AREAS ALONG THEN NORTH
DAKOTA/SOUTH DAKOTA STATE BORDER. HOWEVER...FOR THESE AREAS...THE
FIRE DANGER INDEX WILL BE IN THE LOW END OF THE VERY HIGH
CATEGORY. SINCE THE MARGINAL RED FLAG CONDITIONS WILL BE SHORT
LIVED...HAVE DECIDED NOT TO ISSUE ANY FIRE WEATHER HEADLINES FOR
TODAY.

ANOTHER PERIOD OF VERY HIGH FIRE DANGER IS EXPECTED MONDAY AS A
LOW PRESSURE SYSTEM PULLS WARM AND DRY AIR INTO SOUTHWEST NORTH
DAKOTA...FOLLOWED BY A COLD FRONTAL PASSAGE MONDAY AFTERNOON. THIS
WILL NEED TO BE MONITORED FOR POSSIBLE FIRE WEATHER WATCH.

&&

.HYDROLOGY...
ISSUED AT 257 AM CDT SUN APR 28 2013

THE OVERLAND FLOOD WARNING FOR THE SOURIS BASIN AND UPPER JAMES
BASIN CONTINUES THROUGH AT LEAST THE WEEKEND. THE AGGRESSIVE SNOW MELT
CONTINUES AS TEMPERATURES HAVE REMAINED ABOVE FREEZING...AND
SIGNIFICANT RIVER RESPONSES ARE EXPECTED AT SEVERAL POINTS IN THE
SOURIS BASIN.

LOW PRESSURE SYSTEM WILL BRING SHOWERS AND SCATTERED THUNDERSTORMS
THROUGH THE REGION MONDAY AFTERNOON AND MONDAY NIGHT. THE BEST
CHANCE FOR RAINFALL EXCEEDING ONE HALF INCH WILL BE SOUTH OF THE
SOURIS RIVER VALLEY...BUT WITHIN THE CENTRAL AND SOUTHERN JAMES
RIVER VALLEY. AT THIS TIME SIGNIFICANT RAINFALL IS FORECAST SOUTH
OF THE REMAINING SNOW COVERED AREAS.

&&

.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

UPDATE...RK
SHORT TERM...LTH
LONG TERM...WAA
AVIATION...RK
FIRE WEATHER...LTH/WAA
HYDROLOGY...LTH







AREA FORECAST DISCUSSION

NWS BISMARCK ND

 940 AM CDT SUN APR 28 2013

.UPDATE...
ISSUED AT 932 AM CDT SUN APR 28 2013

UPDATE FOR MINOR CHANGE TO DAYTIME TEMPS/DEWPOINT/SKY COVER. A
COLD FRONT HAS PUSHED INTO NORTHERN NORTH DAKOTA THIS MORNING WITH
A BRISK NORTHWEST WIND BEHIND THE BOUNDARY. NO PRECIPITATION IS
EXPECTED WITH FRONTAL PASSAGE. THE MAIN FORECAST ISSUES CONTINUE
TO BE FLOODING AND FIRE WEATHER...WITH DETAILS BELOW.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 257 AM CDT SUN APR 28 2013

THE MAIN FORECAST ISSUES FOR THE SHORT TERM PERIOD INCLUDE HYDRO
AND FIRE WEATHER ISSUES WHICH ARE OUTLINED BELOW.

A COLD FRONT IS CURRENTLY PUSHING SOUTHEAST OVER NORTH DAKOTA FROM
SOUTHERN CANADA EARLY THIS MORNING. AHEAD OF THE COLD
FRONT...TEMPERATURES HAVE REMAINED WELL ABOVE FREEZING THIS
MORNING...WITH TEMPERATURES MOSTLY IN THE LOWER 50S WEST TO THE
UPPER 40S EAST. THIS HAS ALLOWED FOR CONTINUED MELTING OF THE SNOW
PACK ACROSS NORTH DAKOTA. FOLLOWING THE COLD FRONTAL
PASSAGE...EXPECT COOLER AFTERNOON HIGH TEMPERATURES AS A COOLER
AIRMASS MOVES SOUTH AND OVER THE REGION. AFTERNOON HIGHS WILL
RANGE FROM THE LOW TO MID 50S ACROSS THE NORTH TO THE LOWER 70S
FAR SOUTH CENTRAL. FOR TONIGHT...TEMPERATURES WILL CONTINUE TO BE
ABOVE FREEZING ALLOWING FOR THE MELT TO CONTINUE...WITH THE EXCEPTION OF
THE TURTLE MOUNTAIN REGION WHERE TEMPERATURES MAY DROP TO NEAR 32
DEGREES.

IN REGARDS TO PRECIPITATION CHANCES...PRECIPITATION IS UNLIKELY
DURING THE SHORT TERM PERIOD. THERE HAVE BEEN SOME LIGHT RETURNS
SHOWING UP ON THE RADAR THIS MORNING...BUT WITH DEWPOINT
DEPRESSIONS ON THE ORDER OF 10 TO 20 DEGREES...NOTHING IS REACHING
THE GROUND AND THUS HAVE LEFT POPS LOW. HAVE ALSO ELIMINATED SLIGHT
CHANCE POPS ACROSS THE SOURIS RIVER BASIN BETWEEN 12Z AND
18Z...LATEST 00Z MODEL GUIDANCE AND 07Z RAP RUN KEEPS THE AREA DRY
AS OPPOSED TO THE 12Z ECMWF WHICH HAD SOME LIGHT PRECIP OVER THE
JAMES AND SOURIS RIVER VALLEY.

.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 257 AM CDT SUN APR 28 2013

THE MAIN CONCERNS IN THE EXTENDED ARE RAINFALL ACROSS THE JAMES
RIVER BASIN ON MONDAY AFTERNOON THROUGH MONDAY NIGHT. THIS IS
ASSOCIATED WITH A COMPLEX FRONTAL SYSTEM MOVING ACROSS THE REGION
MONDAY AFTERNOON AND NIGHT. BOTH GFS AND NAM KEEP SOME
INSTABILITY AHEAD OF THE COLD FRONT...AND THIS SHOULD SUPPORT
SCATTERED THUNDERSTORMS. MODELS HAVE BEEN CONSISTENTLY PAINTING
SOME LIGHT TO MODERATE QPF ALONG THE FRONT AS IT MOVES INTO THE
JAMES RIVER VALLEY...AND KEPT THIS CURRENT THINKING GOING THIS
FORECAST PERIOD. AT THIS TIME LOOKS LIKE BETTER THEN A HALF INCH
BUT LESS THAN ONE INCH FOR THE 24 HOUR PERIOD FROM MONDAY AND
MONDAY NIGHT. AT THIS TIME THE SNOW MELT RUNOFF IS NOT AS CRITICAL
ALONG THE JAMES RIVER VALLEY...AND THIS AMOUNT OF QPF WILL LIKELY
BE ABSORBED IN THE SOILS AFTER SEVERAL DAYS OF TEMPERATURES IN
THE 60S AND 70S.

INTERESTING WEATHER PATTERN DEVELOPING AS QUITE AN ANOMALOUS UPPER
LOW DEVELOPS OVER THE CENTRAL PLAINS BY THE END OF THE WEEK.
VARIOUS SCENARIOS HAVE THIS UPPER LOW RETROGRADES AND SPREAD LIGHT
PRECIPITATION INTO NORTHERN PLAINS BY THE END OF THE WEEK. THIS
COULD BE A MIX OF RAIN AND SNOW BY THEN.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 708 AM CDT SUN APR 28 2013

AT 7 AM CDT...A WEAK COLD FRONT WAS ENTERING THE NORTHWEST PORTION
OF THE STATE. NO SIGNIFICANT WEATHER IS ASSOCIATED WITH THIS FRONT
TODAY. THE ONLY AVIATION FACTOR WILL BE NORTHWEST WINDS INCREASING
TO 15 TO 25 MPH. VFR EXPECTED AT ALL TAF SITES FOR THE 12Z TAF
PERIOD.

&&

.FIRE WEATHER...
ISSUED AT 257 AM CDT SUN APR 28 2013

FIRE WEATHER CONDITIONS WILL NOT BE AS SEVERE WITH COOLER TEMPS
AND HIGHER RELATIVE HUMIDITY IN THE UPPER 20S AND 30S.
HOWEVER...THERE WILL BE A FEW HOURS BETWEEN 18Z TO 21Z WHERE THERE
WILL BE MARGINAL RED FLAG CONDITIONS FOR AREAS ALONG THEN NORTH
DAKOTA/SOUTH DAKOTA STATE BORDER. HOWEVER...FOR THESE AREAS...THE
FIRE DANGER INDEX WILL BE IN THE LOW END OF THE VERY HIGH
CATEGORY. SINCE THE MARGINAL RED FLAG CONDITIONS WILL BE SHORT
LIVED...HAVE DECIDED NOT TO ISSUE ANY FIRE WEATHER HEADLINES FOR
TODAY.

ANOTHER PERIOD OF VERY HIGH FIRE DANGER IS EXPECTED MONDAY AS A
LOW PRESSURE SYSTEM PULLS WARM AND DRY AIR INTO SOUTHWEST NORTH
DAKOTA...FOLLOWED BY A COLD FRONTAL PASSAGE MONDAY AFTERNOON. THIS
WILL NEED TO BE MONITORED FOR POSSIBLE FIRE WEATHER WATCH.

&&

.HYDROLOGY...
ISSUED AT 257 AM CDT SUN APR 28 2013

THE OVERLAND FLOOD WARNING FOR THE SOURIS BASIN AND UPPER JAMES
BASIN CONTINUES THROUGH AT LEAST THE WEEKEND. THE AGGRESSIVE SNOW MELT
CONTINUES AS TEMPERATURES HAVE REMAINED ABOVE FREEZING...AND
SIGNIFICANT RIVER RESPONSES ARE EXPECTED AT SEVERAL POINTS IN THE
SOURIS BASIN.

LOW PRESSURE SYSTEM WILL BRING SHOWERS AND SCATTERED THUNDERSTORMS
THROUGH THE REGION MONDAY AFTERNOON AND MONDAY NIGHT. THE BEST
CHANCE FOR RAINFALL EXCEEDING ONE HALF INCH WILL BE SOUTH OF THE
SOURIS RIVER VALLEY...BUT WITHIN THE CENTRAL AND SOUTHERN JAMES
RIVER VALLEY. AT THIS TIME SIGNIFICANT RAINFALL IS FORECAST SOUTH
OF THE REMAINING SNOW COVERED AREAS.

&&

.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

UPDATE...RP KINNEY
SHORT TERM...LTH
LONG TERM...WAA
AVIATION...WAA
FIRE WEATHER...LTH/WAA
HYDROLOGY...LTH






AREA FORECAST DISCUSSION

NWS BISMARCK ND

 715 AM CDT SUN APR 28 2013

.UPDATE...
ISSUED AT 708 AM CDT SUN APR 28 2013

AT 7 AM CDT...A WEAK COLD FRONT WAS POISED TO MOVE THROUGH THE
REGION TODAY. LITTLE PRECIPITATION IS EXPECTED WITH THIS FEATURE
TODAY. SKIES WILL BE PARTLY CLOUDY AND HIGHS WILL BE A BIT COOLER
THAN YESTERDAY. THIS MORNING MAINLY HIGH CLOUDS WERE OVER THE
REGION. REGIONAL RADARS SHOW SCATTERED LIGHT RETURNS...LIKELY ALL
VIRGA. CURRENT FORECAST IS ON TRACK FOR TODAY.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 257 AM CDT SUN APR 28 2013

THE MAIN FORECAST ISSUES FOR THE SHORT TERM PERIOD INCLUDE HYDRO
AND FIRE WEATHER ISSUES WHICH ARE OUTLINED BELOW.

A COLD FRONT IS CURRENTLY PUSHING SOUTHEAST OVER NORTH DAKOTA FROM
SOUTHERN CANADA EARLY THIS MORNING. AHEAD OF THE COLD
FRONT...TEMPERATURES HAVE REMAINED WELL ABOVE FREEZING THIS
MORNING...WITH TEMPERATURES MOSTLY IN THE LOWER 50S WEST TO THE
UPPER 40S EAST. THIS HAS ALLOWED FOR CONTINUED MELTING OF THE SNOW
PACK ACROSS NORTH DAKOTA. FOLLOWING THE COLD FRONTAL
PASSAGE...EXPECT COOLER AFTERNOON HIGH TEMPERATURES AS A COOLER
AIRMASS MOVES SOUTH AND OVER THE REGION. AFTERNOON HIGHS WILL
RANGE FROM THE LOW TO MID 50S ACROSS THE NORTH TO THE LOWER 70S
FAR SOUTH CENTRAL. FOR TONIGHT...TEMPERATURES WILL CONTINUE TO BE
ABOVE FREEZING ALLOWING FOR THE MELT TO CONTINUE...WITH THE EXCEPTION OF
THE TURTLE MOUNTAIN REGION WHERE TEMPERATURES MAY DROP TO NEAR 32
DEGREES.

IN REGARDS TO PRECIPITATION CHANCES...PRECIPITATION IS UNLIKELY
DURING THE SHORT TERM PERIOD. THERE HAVE BEEN SOME LIGHT RETURNS
SHOWING UP ON THE RADAR THIS MORNING...BUT WITH DEWPOINT
DEPRESSIONS ON THE ORDER OF 10 TO 20 DEGREES...NOTHING IS REACHING
THE GROUND AND THUS HAVE LEFT POPS LOW. HAVE ALSO ELIMINATED SLIGHT
CHANCE POPS ACROSS THE SOURIS RIVER BASIN BETWEEN 12Z AND
18Z...LATEST 00Z MODEL GUIDANCE AND 07Z RAP RUN KEEPS THE AREA DRY
AS OPPOSED TO THE 12Z ECWMF WHICH HAD SOME LIGHT PRECIP OVER THE
JAMES AND SOURIS RIVER VALLEY.

.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 257 AM CDT SUN APR 28 2013

THE MAIN CONCERNS IN THE EXTENDED ARE RAINFALL ACROSS THE JAMES
RIVER BASIN ON MONDAY AFTERNOON THROUGH MONDAY NIGHT. THIS IS
ASSOCIATED WITH A COMPLEX FRONTAL SYSTEM MOVING ACROSS THE REGION
MONDAY AFTERNOON AND NIGHT. BOTH GFS AND NAM KEEP SOME
INSTABILITY AHEAD OF THE COLD FRONT...AND THIS SHOULD SUPPORT
SCATTERED THUNDERSTORMS. MODELS HAVE BEEN CONSISTENTLY PAINTING
SOME LIGHT TO MODERATE QPF ALONG THE FRONT AS IT MOVES INTO THE
JAMES RIVER VALLEY...AND KEPT THIS CURRENT THINKING GOING THIS
FORECAST PERIOD. AT THIS TIME LOOKS LIKE BETTER THEN A HALF INCH
BUT LESS THAN ONE INCH FOR THE 24 HOUR PERIOD FROM MONDAY AND
MONDAY NIGHT. AT THIS TIME THE SNOW MELT RUNOFF IS NOT AS CRITICAL
ALONG THE JAMES RIVER VALLEY...AND THIS AMOUNT OF QPF WILL LIKELY
BE ABSORBED IN THE SOILS AFTER SEVERAL DAYS OF TEMPERATURES IN
THE 60S AND 70S.

INTERESTING WEATHER PATTERN DEVELOPING AS QUITE AN ANOMALOUS UPPER
LOW DEVELOPS OVER THE CENTRAL PLAINS BY THE END OF THE WEEK.
VARIOUS SCENARIOS HAVE THIS UPPER LOW RETROGRADES AND SPREAD LIGHT
PRECIPITATION INTO NORTHERN PLAINS BY THE END OF THE WEEK. THIS
COULD BE A MIX OF RAIN AND SNOW BY THEN.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 708 AM CDT SUN APR 28 2013

AT 7 AM CDT...A WEAK COLD FRONT WAS ENTERING THE NORTHWEST PORTION
OF THE STATE. NO SIGNIFICANT WEATHER IS ASSOCIATED WITH THIS FRONT
TODAY. THE ONLY AVIATION FACTOR WILL BE NORTHWEST WINDS INCREASING
TO 15 TO 25 MPH. VFR EXPECTED AT ALL TAF SITES FOR THE 12Z TAF
PERIOD.

&&

.FIRE WEATHER...
ISSUED AT 257 AM CDT SUN APR 28 2013

FIRE WEATHER CONDITIONS WILL NOT BE AS SEVERE WITH COOLER TEMPS
AND HIGHER RELATIVE HUMIDITY IN THE UPPER 20S AND 30S.
HOWEVER...THERE WILL BE A FEW HOURS BETWEEN 18Z TO 21Z WHERE THERE
WILL BE MARGINAL RED FLAG CONDITIONS FOR AREAS ALONG THEN NORTH
DAKOTA/SOUTH DAKOTA STATE BORDER. HOWEVER...FOR THESE AREAS...THE
FIRE DANGER INDEX WILL BE IN THE LOW END OF THE VERY HIGH
CATEGORY. SINCE THE MARGINAL RED FLAG CONDITIONS WILL BE SHORT
LIVED...HAVE DECIDED NOT TO ISSUE ANY FIRE WEATHER HEADLINES FOR
TODAY.

ANOTHER PERIOD OF VERY HIGH FIRE DANGER IS EXPECTED MONDAY AS A
LOW PRESSURE SYSTEM PULLS WARM AND DRY AIR INTO SOUTHWEST NORTH
DAKOTA...FOLLOWED BY A COLD FRONTAL PASSAGE MONDAY AFTERNOON. THIS
WILL NEED TO BE MONITORED FOR POSSIBLE FIRE WEATHER WATCH.

&&

.HYDROLOGY...
ISSUED AT 257 AM CDT SUN APR 28 2013

THE OVERLAND FLOOD WARNING FOR THE SOURIS BASIN AND UPPER JAMES
BASIN CONTINUES THROUGH AT LEAST THE WEEKEND. THE AGGRESSIVE SNOW MELT
CONTINUES AS TEMPERATURES HAVE REMAINED ABOVE FREEZING...AND
SIGNIFICANT RIVER RESPONSES ARE EXPECTED AT SEVERAL POINTS IN THE
SOURIS BASIN.

LOW PRESSURE SYSTEM WILL BRING SHOWERS AND SCATTERED THUNDERSTORMS
THROUGH THE REGION MONDAY AFTERNOON AND MONDAY NIGHT. THE BEST
CHANCE FOR RAINFALL EXCEEDING ONE HALF INCH WILL BE SOUTH OF THE
SOURIS RIVER VALLEY...BUT WITHIN THE CENTRAL AND SOUTHERN JAMES
RIVER VALLEY. AT THIS TIME SIGNIFICANT RAINFALL IS FORECAST SOUTH
OF THE REMAINING SNOW COVERED AREAS.

&&

.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

UPDATE...WAA
SHORT TERM...LTH
LONG TERM...WAA
AVIATION...WAA
FIRE WEATHER...LTH/WAA
HYDROLOGY...LTH







AREA FORECAST DISCUSSION

NWS BISMARCK ND

 349 AM CDT SUN APR 28 2013

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 257 AM CDT SUN APR 28 2013

THE MAIN FORECAST ISSUES FOR THE SHORT TERM PERIOD INCLUDE HYDRO
AND FIRE WEATHER ISSUES WHICH ARE OUTLINED BELOW.

A COLD FRONT IS CURRENTLY PUSHING SOUTHEAST OVER NORTH DAKOTA FROM
SOUTHERN CANADA EARLY THIS MORNING. AHEAD OF THE COLD
FRONT...TEMPERATURES HAVE REMAINED WELL ABOVE FREEZING THIS
MORNING...WITH TEMPERATURES MOSTLY IN THE LOWER 50S WEST TO THE
UPPER 40S EAST. THIS HAS ALLOWED FOR CONTINUED MELTING OF THE SNOW
PACK ACROSS NORTH DAKOTA. FOLLOWING THE COLD FRONTAL
PASSAGE...EXPECT COOLER AFTERNOON HIGH TEMPERATURES AS A COOLER
AIRMASS MOVES SOUTH AND OVER THE REGION. AFTERNOON HIGHS WILL
RANGE FROM THE LOW TO MID 50S ACROSS THE NORTH TO THE LOWER 70S
FAR SOUTH CENTRAL. FOR TONIGHT...TEMPERATURES WILL CONTINUE TO BE
ABOVE FREEZING ALLOWING FOR THE MELT TO CONTINUE...WITH THE EXCEPTION OF
THE TURTLE MOUNTAIN REGION WHERE TEMPERATURES MAY DROP TO NEAR 32
DEGREES.

IN REGARDS TO PRECIPITATION CHANCES...PRECIPITATION IS UNLIKELY
DURING THE SHORT TERM PERIOD. THERE HAVE BEEN SOME LIGHT RETURNS
SHOWING UP ON THE RADAR THIS MORNING...BUT WITH DEWPOINT
DEPRESSIONS ON THE ORDER OF 10 TO 20 DEGREES...NOTHING IS REACHING
THE GROUND AND THUS HAVE LEFT POPS LOW. HAVE ALSO ELIMINATED SLIGHT
CHANCE POPS ACROSS THE SOURIS RIVER BASIN BETWEEN 12Z AND
18Z...LATEST 00Z MODEL GUIDANCE AND 07Z RAP RUN KEEPS THE AREA DRY
AS OPPOSED TO THE 12Z ECWMF WHICH HAD SOME LIGHT PRECIP OVER THE
JAMES AND SOURIS RIVER VALLEY.

.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 257 AM CDT SUN APR 28 2013

THE MAIN CONCERNS IN THE EXTENDED ARE RAINFALL ACROSS THE JAMES
RIVER BASIN ON MONDAY AFTERNOON THROUGH MONDAY NIGHT. THIS IS
ASSOCIATED WITH A COMPLEX FRONTAL SYSTEM MOVING ACROSS THE REGION
MONDAY AFTERNOON AND NIGHT. BOTH GFS AND NAM KEEP SOME
INSTABILITY AHEAD OF THE COLD FRONT...AND THIS SHOULD SUPPORT
SCATTERED THUNDERSTORMS. MODELS HAVE BEEN CONSISTENTLY PAINTING
SOME LIGHT TO MODERATE QPF ALONG THE FRONT AS IT MOVES INTO THE
JAMES RIVER VALLEY...AND KEPT THIS CURRENT THINKING GOING THIS
FORECAST PERIOD. AT THIS TIME LOOKS LIKE BETTER THEN A HALF INCH
BUT LESS THAN ONE INCH FOR THE 24 HOUR PERIOD FROM MONDAY AND
MONDAY NIGHT. AT THIS TIME THE SNOW MELT RUNOFF IS NOT AS CRITICAL
ALONG THE JAMES RIVER VALLEY...AND THIS AMOUNT OF QPF WILL LIKELY
BE ABSORBED IN THE SOILS AFTER SEVERAL DAYS OF TEMPERATURES IN
THE 60S AND 70S.

INTERESTING WEATHER PATTERN DEVELOPING AS QUITE AN ANOMALOUS UPPER
LOW DEVELOPS OVER THE CENTRAL PLAINS BY THE END OF THE WEEK.
VARIOUS SCENARIOS HAVE THIS UPPER LOW RETROGRADES AND SPREAD LIGHT
PRECIPITATION INTO NORTHERN PLAINS BY THE END OF THE WEEK. THIS
COULD BE A MIX OF RAIN AND SNOW BY THEN.


&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 257 AM CDT SUN APR 28 2013

VFR CONDITIONS WILL CONTINUE THROUGH THE 06 UTC TAF PERIOD WITH
SCATTERED TO BROKEN MID AND HIGH LEVEL CLOUDS. GUSTY NORTHWESTERLY
WINDS WILL DEVELOP ACROSS WESTERN AND CENTRAL NORTH DAKOTA BY LATE
THIS MORNING AND SUBSIDE SHORTLY AFTER SUNSET TO BELOW 10 KTS.

&&

.FIRE WEATHER...
ISSUED AT 257 AM CDT SUN APR 28 2013

FIRE WEATHER CONDITIONS WILL NOT BE AS SEVERE WITH COOLER TEMPS
AND HIGHER RELATIVE HUMIDITY IN THE UPPER 20S AND 30S.
HOWEVER...THERE WILL BE A FEW HOURS BETWEEN 18Z TO 21Z WHERE THERE
WILL BE MARGINAL RED FLAG CONDITIONS FOR AREAS ALONG THEN NORTH
DAKOTA/SOUTH DAKOTA STATE BORDER. HOWEVER...FOR THESE AREAS...THE
FIRE DANGER INDEX WILL BE IN THE LOW END OF THE VERY HIGH
CATEGORY. SINCE THE MARGINAL RED FLAG CONDITIONS WILL BE SHORT
LIVED...HAVE DECIDED NOT TO ISSUE ANY FIRE WEATHER HEADLINES FOR
TODAY.

ANOTHER PERIOD OF VERY HIGH FIRE DANGER IS EXPECTED MONDAY AS A
LOW PRESSURE SYSTEM PULLS WARM AND DRY AIR INTO SOUTHWEST NORTH
DAKOTA...FOLLOWED BY A COLD FRONTAL PASSAGE MONDAY AFTERNOON. THIS
WILL NEED TO BE MONITORED FOR POSSIBLE FIRE WEATHER WATCH.

&&

.HYDROLOGY...
ISSUED AT 257 AM CDT SUN APR 28 2013

THE OVERLAND FLOOD WARNING FOR THE SOURIS BASIN AND UPPER JAMES
BASIN CONTINUES THROUGH AT LEAST THE WEEKEND. THE AGGRESSIVE SNOW MELT
CONTINUES AS TEMPERATURES HAVE REMAINED ABOVE FREEZING...AND
SIGNIFICANT RIVER RESPONSES ARE EXPECTED AT SEVERAL POINTS IN THE
SOURIS BASIN.

LOW PRESSURE SYSTEM WILL BRING SHOWERS AND SCATTERED THUNDERSTORMS
THROUGH THE REGION MONDAY AFTERNOON AND MONDAY NIGHT. THE BEST
CHANCE FOR RAINFALL EXCEEDING ONE HALF INCH WILL BE SOUTH OF THE
SOURIS RIVER VALLEY...BUT WITHIN THE CENTRAL AND SOUTHERN JAMES
RIVER VALLEY. AT THIS TIME SIGNIFICANT RAINFALL IS FORECAST SOUTH
OF THE REMAINING SNOW COVERED AREAS.

&&

.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...LTH
LONG TERM...WAA
AVIATION...LTH
FIRE WEATHER...LTH/WAA
HYDROLOGY...LTH









AREA FORECAST DISCUSSION

NWS WILMINGTON OH

 1033 PM EDT MON APR 29 2013

.SYNOPSIS...
HIGH PRESSURE AND A DRIER AIRMASS WILL BUILD INTO THE REGION
THROUGH WEDNESDAY. A SLOW MOVING UPPER LEVEL LOW WILL DIVE SOUTH
THROUGH THE CENTRAL U.S. AT THE END OF THE WEEK WITH AN
ACCOMPANYING SURFACE LOW MOVING NORTH ALONG THE MISSISSIPPI. AT
SOME POINT OVER THE WEEKEND...THESE SYSTEMS WILL BECOME STACKED
AND BEGIN TO TRACK EAST THROUGH THE OHIO VALLEY.

&&

.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
CLOUD DECK HAS RAPIDLY ERODED OVER THE PAST COUPLE HOURS WHICH IS
RIGHT IN LINE WITH THE 00Z 4/30 NAM AND RECENT RAP RUNS. BOTH THE
NAM AND RAP ALSO HAVE UPSTREAM CLOUDS OVER IN/IL GRADUALLY ERODING
AS THEY APPROACH THE AREA OVERNIGHT. KEPT MAJORITY OF FA UNDER
MOSTLY CLEAR SKIES TONIGHT WITH THE EXCEPTION OF PARTLY CLOUDY IN
THE FAR NORTH. MAIN FORECAST CONCERN WILL BE POSSIBILITY OFF FOG
GIVEN PLENTIFUL LOW LEVEL MOISTURE (DEW POINTS STILL IN THE
50S)...LIGHT TO CALM WINDS...AND A FAVORABLE SETUP FOR RADIATIONAL
COOLING. PATCHY DENSE FOG WILL BE A POSSIBILITY...ESPECIALLY IN
LOW LYING AREAS. PREVIOUS MIN TEMP FORECAST IN THE LOWER 50S STILL
LOOKS TO BE ON TRACK.

&&

.SHORT TERM /6 AM TUESDAY MORNING THROUGH WEDNESDAY NIGHT/...
MID AND UPPER LEVEL RIDGING WILL DEVELOP ACROSS THE OHIO VALLEY
TUESDAY INTO WEDNESDAY AHEAD OF THE DIGGING UPPER LOW IN THE PLAINS.
THIS WILL RESULT IN DRY CONDITIONS AND A DECENT WARM UP THROUGH
MIDWEEK. TEMPERATURES ON TUESDAY SHOULD PUSH INTO THE MID TO UPPER
70S WITH HIGHS ON WEDNESDAY IN THE UPPER 70S TO LOWER 80S.
OVERNIGHT LOWS WILL BE SEASONABLY MILD IN THE LOW TO MID 50S. THIS
IS SLIGHTLY ABOVE CLIMO NORMALS IN THE UPPER 40S.

&&

.LONG TERM /THURSDAY THROUGH MONDAY/...
ENERGY DIGGING FROM THE NRN ROCKIES WILL CARVE OUT AN UPPER LEVEL
TROF OVER THE NATIONS MID SECTION WITH AN UPPER LOW EVENTUALLY
CLOSING OFF OVER THE CENTRAL PLAINS BY FRIDAY.

STRONG RIDGING AHEAD OF THIS SYSTEM WILL PROVIDE WARM TEMPERATURES
THURSDAY WITH HIGHS 7 TO 10 DEGREES ABOVE NORMAL...RANGING FROM MID
70S NW TO NEAR 80 SE.

NUMERICAL MODEL SOLNS HAVE BEEN SHOWING A HIGHER THAN NORMAL DEGREE
OF SPREAD REGARDING PLACEMENT AND MOVEMENT OF THIS UPPER LOW. ECMWF
HAS HAD BEST RUN TO RUN CONSISTENCY. PREVIOUS ECMWF RUNS AND CMC
RUNS WERE STALLING OUT THE EASTWARD PROGRESSION OF THE UPPER LOW
OVER THE MID MS VLY ON FRIDAY AND THEN LIFTING IT NNW INTO THE NRN
PLAINS SATURDAY. GFS SOLN HAS FLIPPED BACK AND FORTH AND THE LATEST
RUN TAKES THE LOW VERY SLOWLY EASTWARD THRU THE LWR MS VALLEY THIS
WEEKEND AND INTO TN VLY BY EARLY NEXT WEEK...PASSING TO OUR SOUTH.
LATEST NOGAPS POINTS TOWARD THE NW SOLN...WHILE THE GFS ENSEMBLE
MEAN SHOWS EVIDENCE FOR THE LOW STALLING TO OUR WEST. LATEST 12Z
DETERMINISTIC ECMWF SOLN DIGS THE LOW FARTHER SOUTH AND THEN LIFTS
IT NE THIS WEEKEND INTO THE UPPER MS VLY BY SUNDAY EVENING AND THEN
ACRS THE GREAT LAKES EARLY NEXT WEEK.

WITH A WIDE ARRAY OF SOLNS...UNCERTAINTY IS CONSIDERABLY HIGHER THAN
NORMAL FOR THE FCST NEXT WEEK END INTO EARLY NEXT WEEK. HAVE TRENDED
THE FCST SOLN TOWARD THE ECMWF SOLN WITH THE UPR LOW PASSING TO OUR
NORTH. DUE TO LOW CONFIDENCE HAVE LIMITED POPS TO SLIGHT CHC ACRS
THE FAR WEST FRIDAY WITH THE APPROACH OF SFC FRONTAL SYSTEM. WILL
CONTINUE ONLY SLIGHT CHC POPS SATURDAY ACRS THE WEST. HAVE SPREAD
LOW CHANCE POPS ACRS ENTIRE FA FOR SUNDAY/MONDAY TIME FRAME.

TEMP WISE...AFTER ABOVE NORMAL READINGS ON THURSDAY...TEMPS LOOK TO
BE A LTL CLOSER TO NORMAL FRIDAY AND INTO NEXT WEEKEND.

&&

.AVIATION /02Z TUESDAY THROUGH SATURDAY/...
VFR DECK ACROSS THE REGION AT THE BEGINNING OF THE PERIOD SHOULD
SCATTER BUT MAY NOT COMPLETELY GO AWAY. GUIDANCE IS SUGGESTING
THAT THERE COULD BE ANOTHER PERIOD OF LOWER VFR CEILINGS LATER IN
THE NIGHT. HOWEVER CONFIDENCE IS NOT PARTICULARLY HIGH IN THIS
REGARD. BUT MOISTURE IN THE 3000 TO 5000 FT DECK...EVEN IF IT DOES
NOT RESULT IN CLOUDS...COULD BE AN INHIBITING FACTOR FOR FOG
FORMATION. STILL BELIEVE THAT MVFR VISIBILITY RESTRICTIONS WILL
DEVELOP AT ALL TERMINALS. BUT HAVE LIMITED ANY PERIOD OF IFR
VISIBILITY TO THE NORMALLY LOWER SITES. CONDITIONS WILL RETURN TO
VFR SHORTLY AFTER 12Z WITH FEW TO SCATTERED CUMULUS DURING THE
DAY.

OUTLOOK...NO SIGNIFICANT WEATHER EXPECTED.

&&

.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.

&&

$$
SYNOPSIS...FRANKS
NEAR TERM...KURZ
SHORT TERM...FRANKS
LONG TERM...AR
AVIATION...







AREA FORECAST DISCUSSION

NWS CLEVELAND OH

 540 PM EDT SUN APR 28 2013

.SYNOPSIS...
LOW PRESSURE ALONG THE INDIANA AND OHIO BORDER WILL DRIFT NORTH
AND GRADUALLY DISSIPATE BY MONDAY MORNING. HIGH PRESSURE WILL
BUILD ACROSS THE AREA LATE MONDAY THROUGH AT LEAST MIDWEEK.

&&

.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
THE EARLY EVENING UPDATE WAS TO REFINE TEMPERATURES THROUGH
MIDNIGHT...A LITTLE COOLER AT FIRST WHERE IT HAS BEEN
RAINING...THEN A COUPLE OF DEGREES WARMER THAN THE EARLIER
FORECAST SINCE HIGH DEWPOINTS AND WARMER AIR ARE MOVING IN FROM
THE SOUTH THIS EVENING.

EMPHASIZED SHOWERS MAINLY FOR THIS EVENING FOR NORTHWEST OHIO AND
BEFORE MIDNIGHT NORTH CENTRAL OHIO. DID NOT TRY TO TIME THE
SHOWERS AS MUCH NE OH/NW PA ALTHOUGH THE SHOWERS WILL ALMOST
CERTAINLY TAPER OFF SOMEWHAT DURING THE EARLY MORNING HOURS.

EARLIER DISCUSSION...
KIND OF A TRICKY FORECAST FOR TONIGHT. PRECIP COVERAGE CONTINUES
TO DISSIPATE. COMMA HEAD FROM THE UPPER LOW CLEARLY VISIBLE ON THE
RADAR. THE MAIN AREA OF RAIN IS NOW MOVING OUT OVER LAKE ERIE BUT
NEW DEVELOPMENT CONTINUES TO THE SOUTH. THIS SECOND WAVE OF PRECIP
WILL BE SCATTERED IN NATURE THIS EVENING. ALL OF THE NEW GUIDANCE
INCLUDING THE LATEST HRRR SHOW ABOUT 50 PERCENT COVERAGE MOST OF
THE EVENING. THE SHOWERS WILL BE CELLULAR IN NATURE WHICH WOULD
LEAD ME TO BELIEVE THERE COULD BE SOME ISOLATED THUNDER. JUST
CAN`T SEE THAT HAPPENING THOUGH GIVEN THE THICK CLOUDS AND LACK OF
INSTABILITY OVER THE AREA. WILL REMOVE THE EARLIER MENTION OF
THUNDER FROM THE FORECAST. BY 06Z ANY REMAINING PRECIP SHOULD BE
OVER THE EAST HALF OF THE AREA. CLOUDS EXTEND WEST ACROSS THE
GREAT LAKES AND SEE NO CHANCE OF CLEARING TONIGHT. SOME OF THE
GUIDANCE IS SUGGESTING SOME FOG DEVELOPMENT OVERNIGHT SO THE
EVENING CREW WILL HAVE TO WATCH THAT. USED A BLEND OF GUIDANCE
TEMPS.

&&

.SHORT TERM /6 AM MONDAY MORNING THROUGH WEDNESDAY NIGHT/...
MODELS IN FAIR AGREEMENT DURING THE PERIOD AND SHOW AN UPPER
TROUGH ROTATING ACROSS THE REGION LATE TONIGHT AND MONDAY. THIS
FEATURE SHOULD KICK OFF A FEW MORE SHOWERS WITH BEST CHANCES BEING
IN THE EAST. SYNOPTIC SCALE SUBSIDENCE BEHIND THE WAVE SHOULD
BRING AN END TO THE PRECIP MONDAY EVENING. THE REMAINDER OF THE
PERIOD SHOULD THEN BE DRY AS THE LOCAL AREA REMAINS BETWEEN WEAK
SYSTEMS. WEAK RIDING WILL TRY TO OCCUR DURING THE PERIOD. THIS MAY
BE ENOUGH TO BREAK UP THE CLOUDS SOME BUT NOT ENOUGH TO CLEAR
THINGS OUT. THE AREA WILL SEE A PROLONGED PERIOD OF S TO SW FLOW
WHICH WILL MODERATE TEMPS. HIGHS COULD GET TO 70 TOMORROW IN THE
WEST AND ACROSS MOST OF THE AREA ON TUESDAY AND WEDNESDAY. LAKE
BREEZES APPEAR LIKELY IN THE AFTERNOON SO THE IMMEDIATE LAKESHORE
AREAS WILL BE COOLER. HAVE USED A BLEND OF GUIDANCE MOST OF THE
PERIOD.

&&

.LONG TERM /THURSDAY THROUGH SUNDAY/...
HIGH PRESSURE APPEARS IT WILL BECOME THE DOMINATING WEATHER FEATURE
ACROSS THE AREA FOR A GOOD PART OF THE EXTENDED PERIODS. UPPER LEVEL
RIDGE BUILDS OVER THE EASTERN UNITED STATES AND SETS UP A SURFACE
HIGH OVER THE EASTERN SEABOARD.  THIS FEATURE WILL KEEP A SOUTHERLY
COMPONENT TO THE WIND ALLOWING FOR WARM AIR ADVECTION TO TAKE PLACE
INTO FRIDAY. FRONTAL BOUNDARY WILL STALL WEST OF THE REGION WILL
MAKE SLOW PROGRESS INTO THE AREA ON SATURDAY.  THIS FEATURE WILL
BRING THE NEXT CHANCE OF RAIN SATURDAY INTO SATURDAY NIGHT. THERE IS
THE POSSIBILITY THAT THE FRONT COULD LINGER INTO THE AREA ON SUNDAY
WITH A CHANCE OF SHOWERS.  MADE A FEW ADJUSTMENTS TO TEMPERATURES
BUT NOTHING MAJOR AS MODELS ARE FAIRLY CONSISTENT WITH YESTERDAYS
RUN.

&&

.AVIATION /22Z SUNDAY THROUGH FRIDAY/...
RAIN CONTINUES TO ROTATE THROUGH THE AREA THIS AFTERNOON WITH THE
MAIN BAND LIFTING NORTHEAST ACROSS NORTHEAST OHIO AND NORTHWEST
PENNSYLVANIA. SECONDARY AREA OF CONVECTIVE SHOWERS CONTINUES TO
DEVELOP OVER SOUTH CENTRAL OHIO AND THIS ACTIVITY WILL LIFT
NORTHEAST. ANTICIPATE THE ONLY PLACE WE MAY HEAR THUNDER IS AT
AKRON CANTON AND YOUNGSTOWN. WILL LEAVE MENTION OF THUNDER OUT OF
THE FORECAST ELSEWHERE. PRECIPITATION IS JUST ABOUT DONE IN
NORTHWEST OHIO FOR THE WIDESPREAD RAIN. MAY SEE SOME SCATTERED
SHOWER ACTIVITY THROUGH THE REST OF THE AFTERNOON.

CEILINGS WILL REMAIN FAIRLY LOW THROUGH MUCH OF THE PERIOD BUT
WILL SEE SOME IMPROVEMENT TOWARD THE END OF THE FORECAST PERIOD.
VISIBILITIES COULD BE REDUCED OVERNIGHT BY FOG DEVELOPMENT DUE TO
MOIST GROUND. NOT EXPECTING ANY WORSE THAN A HALF MILE AT ANY
LOCATION.

.OUTLOOK...NON-VFR POSSIBLE IN FOG THURSDAY MORNING.

&&

.MARINE...
ONCE THIS STORM SYSTEM MOVES NORTHEAST OF THE AREA TONIGHT AND
MONDAY MORNING...LOOKING AT RATHER QUIET WEATHER ON THE LAKE. NOT
ANTICIPATING ANY STRONG STORM SYSTEMS TO SUPPORT STRONGER WINDS.
THEREFORE...WILL KEEP WINDS LIGHT AND WAVES ON THE LIGHT SIDE
THROUGH THE PERIOD.

&&

.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...NONE.

&&

$$
SYNOPSIS...KOSARIK/KUBINA
NEAR TERM...KOSARIK/KUBINA
SHORT TERM...KUBINA
LONG TERM...LOMBARDY
AVIATION...LOMBARDY
MARINE...LOMBARDY







AREA FORECAST DISCUSSION

NWS CLEVELAND OH

 312 PM EDT SUN APR 28 2013

.SYNOPSIS...
LOW PRESSURE OVER CENTRAL INDIANA WILL MOVE INTO NORTHWEST OHIO
AND DISSIPATE OVERNIGHT. HIGH PRESSURE WILL BUILD OVER THE AREA
LATE MONDAY THROUGH MIDWEEK.

&&

.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
KIND OF A TRICKY FORECAST FOR TONIGHT. PRECIP COVERAGE CONTINUES
TO DISSIPATE. COMMA HEAD FROM THE UPPER LOW CLEARLY VISIBLE ON THE
RADAR. THE MAIN AREA OF RAIN IS NOW MOVING OUT OVER LAKE ERIE BUT
NEW DEVELOPMENT CONTINUES TO THE SOUTH. THIS SECOND WAVE OF PRECIP
WILL BE SCATTERED IN NATURE THIS EVENING. ALL OF THE NEW GUIDANCE
INCLUDING THE LATEST HRRR SHOW ABOUT 50 PERCENT COVERAGE MOST OF
THE EVENING. THE SHOWERS WILL BE CELLULAR IN NATURE WHICH WOULD
LEAD ME TO BELIEVE THERE COULD BE SOME ISOLATED THUNDER. JUST
CAN`T SEE THAT HAPPENING THOUGH GIVEN THE THICK CLOUDS AND LACK OF
INSTABILITY OVER THE AREA. WILL REMOVE THE EARLIER MENTION OF
THUNDER FROM THE FORECAST. BY 06Z ANY REMAINING PRECIP SHOULD BE
OVER THE EAST HALF OF THE AREA. CLOUDS EXTEND WEST ACROSS THE
GREAT LAKES AND SEE NO CHANCE OF CLEARING TONIGHT. SOME OF THE
GUIDANCE IS SUGGESTING SOME FOG DEVELOPMENT OVERNIGHT SO THE
EVENING CREW WILL HAVE TO WATCH THAT. USED A BLEND OF GUIDANCE
TEMPS.

&&

.SHORT TERM /6 AM MONDAY MORNING THROUGH WEDNESDAY NIGHT/...
MODELS IN FAIR AGREEMENT DURING THE PERIOD AND SHOW AN UPPER
TROUGH ROTATING ACROSS THE REGION LATE TONIGHT AND MONDAY. THIS
FEATURE SHOULD KICK OFF A FEW MORE SHOWERS WITH BEST CHANCES BEING
IN THE EAST. SYNOPTIC SCALE SUBSIDENCE BEHIND THE WAVE SHOULD
BRING AN END TO THE PRECIP MONDAY EVENING. THE REMAINDER OF THE
PERIOD SHOULD THEN BE DRY AS THE LOCAL AREA REMAINS BETWEEN WEAK
SYSTEMS. WEAK RIDING WILL TRY TO OCCUR DURING THE PERIOD. THIS MAY
BE ENOUGH TO BREAK UP THE CLOUDS SOME BUT NOT ENOUGH TO CLEAR
THINGS OUT. THE AREA WILL SEE A PROLONGED PERIOD OF S TO SW FLOW
WHICH WILL MODERATE TEMPS. HIGHS COULD GET TO 70 TOMORROW IN THE
WEST AND ACROSS MOST OF THE AREA ON TUESDAY AND WEDNESDAY. LAKE
BREEZES APPEAR LIKELY IN THE AFTERNOON SO THE IMMEDIATE LAKESHORE
AREAS WILL BE COOLER. HAVE USED A BLEND OF GUIDANCE MOST OF THE
PERIOD.

&&

.LONG TERM /THURSDAY THROUGH SATURDAY/...
HIGH PRESSURE APPEARS IT WILL BECOME THE DOMINATING WEATHER FEATURE
ACROSS THE AREA FOR A GOOD PART OF THE EXTENDED PERIODS. UPPER LEVEL
RIDGE BUILDS OVER THE EASTERN UNITED STATES AND SETS UP A SURFACE
HIGH OVER THE EASTERN SEABOARD.  THIS FEATURE WILL KEEP A SOUTHERLY
COMPONENT TO THE WIND ALLOWING FOR WARM AIR ADVECTION TO TAKE PLACE
INTO FRIDAY. FRONTAL BOUNDARY WILL STALL WEST OF THE REGION WILL
MAKE SLOW PROGRESS INTO THE AREA ON SATURDAY.  THIS FEATURE WILL
BRING THE NEXT CHANCE OF RAIN SATURDAY INTO SATURDAY NIGHT. THERE IS
THE POSSIBILITY THAT THE FRONT COULD LINGER INTO THE AREA ON SUNDAY
WITH A CHANCE OF SHOWERS.  MADE A FEW ADJUSTMENTS TO TEMPERATURES
BUT NOTHING MAJOR AS MODELS ARE FAIRLY CONSISTENT WITH YESTERDAYS
RUN.

&&

.AVIATION /19Z SUNDAY THROUGH FRIDAY/...
RAIN CONTINUES TO ROTATE THROUGH THE AREA THIS AFTERNOON WITH THE
MAIN BAND LIFTING NORTHEAST ACROSS NORTHEAST OHIO AND NORTHWEST
PENNSYLVANIA. SECONDARY AREA OF CONVECTIVE SHOWERS CONTINUES TO
DEVELOP OVER SOUTH CENTRAL OHIO AND THIS ACTIVITY WILL LIFT
NORTHEAST. ANTICIPATE THE ONLY PLACE WE MAY HEAR THUNDER IS AT
AKRON CANTON AND YOUNGSTOWN. WILL LEAVE MENTION OF THUNDER OUT OF
THE FORECAST ELSEWHERE. PRECIPITATION IS JUST ABOUT DONE IN
NORTHWEST OHIO FOR THE WIDESPREAD RAIN. MAY SEE SOME SCATTERED
SHOWER ACTIVITY THROUGH THE REST OF THE AFTERNOON.

CEILINGS WILL REMAIN FAIRLY LOW THROUGH MUCH OF THE PERIOD BUT
WILL SEE SOME IMPROVEMENT TOWARD THE END OF THE FORECAST PERIOD.
VISIBILITIES COULD BE REDUCED OVERNIGHT BY FOG DEVELOPMENT DUE TO
MOIST GROUND. NOT EXPECTING ANY WORSE THAN A HALF MILE AT ANY
LOCATION.

.OUTLOOK...NON-VFR POSSIBLE IN FOG THURSDAY MORNING.

&&

.MARINE...
ONCE THIS STORM SYSTEM MOVES NORTHEAST OF THE AREA TONIGHT AND
MONDAY MORNING...LOOKING AT RATHER QUIET WEATHER ON THE LAKE. NOT
ANTICIPATING ANY STRONG STORM SYSTEMS TO SUPPORT STRONGER WINDS.
THEREFORE...WILL KEEP WINDS LIGHT AND WAVES ON THE LIGHT SIDE
THROUGH THE PERIOD.

&&

.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...NONE.

&&

$$
SYNOPSIS...KUBINA
NEAR TERM...KUBINA
SHORT TERM...KUBINA
LONG TERM...LOMBARDY
AVIATION...LOMBARDY
MARINE...LOMBARDY







AREA FORECAST DISCUSSION

NWS GREENVILLE-SPARTANBURG SC

 802 PM EDT MON APR 29 2013

.SYNOPSIS...
A RIDGE OF HIGH PRESSURE WILL STRENGTHEN ATOP THE REGION THROUGH
MIDWEEK AND LINGER INTO THE UPCOMING WEEKEND.

&&

.NEAR TERM /THROUGH TUESDAY/...
AS OF 730 PM...LATEST RUC AND WATER VAPOR IMAGERY SHOW THE AXIS OF A
SHORT WAVE ALREADY EAST OF THE FCST AREA. NVA BEHIND THIS FEATURE
WAS APPARENTLY DOING ITS BEST TO SQUASH MOST OF THE ENHANCED CU FROM
GROWING TO ANY GREAT EXTENT. STILL...A FEW SHOWERS HAVE MANAGED TO
DEVELOP...MAINLY NEAR THE BLUE RIDGE. WILL KEEP A SLIGHT CHC POP TO
ACCOUNT FOR THIS MAINLY OVER THE NC PART OF THE FCST AREA FROM THE
BLUE RIDGE TO THE PIEDMONT THROUGH MID EVENING. OUR ATTENTION TURNS
TO THE DEVELOPMENT OF DENSE FOG DURING THE EARLY MORNING HOURS. THE
LATEST MODEL GUIDANCE IS NOT QUITE AS IMPRESSED WITH OUR
PROSPECTS... PERHAPS BECAUSE SOME SLIGHTLY DRIER AIR HAS MIXED IN.
HAVE BACKED OFF ON WORDING BUT WILL BE POISED TO LEAP IF FOG
DEVELOPS BY LATE EVENING. MORE LIKELY...WILL WAIT UNTIL EARLY
MORNING HOURS BEFORE ISSUING AN ADVISORY BECAUSE OF UNCERTAINTY
CREEPING IN.

PREVIOUS DISCUSSION...
AS OF 230 PM EDT MONDAY...A SHORT WAVE TROUGH WILL PUSH EAST OF THE
REGION THIS EVENING. NVA AND DEEP LAYER RIDGING WILL FOLLOW IN IT/S
WAKE. THERE COULD STILL BE SOME SHOWER OR THUNDERSTORM ACTIVITY LATE
THIS AFTERNOON AND EVENING...PARTICULARLY ALONG THE BLUE RIDGE AND
OUT ACROSS THE NC FOOTHILLS. SO I/VE HELD ON TO SOME LOW END CHANCE
POPS ACROSS THESE ZONES. LATER TONIGHT THE STAGE LOOKS SET FOR
WIDESPREAD DENSE FOG. THE NAM CONDENSATION PRESSURE DEFICITS FALL TO
ZERO ACROSS ALL OF THE FA EXCEPT THE MTN RIDGE-TOPS. THERE WILL BE
DEEP LAYER DRYING AND WINDS WILL BE LIGHT. WE HAD WIDESPREAD RAIN
OVER THE PAST COUPLE DAYS AND THE GROUND IS QUITE MOIST. I DEBATED
ISSUING A DENSE FOG ADVISORY...BUT THERE IS JUST ENOUGH LLVL FLOW
THAT A LOW STRATUS DECK COULD DEVELOP INSTEAD. ALSO...THE
NEIGHBORING OFFICES I SPOKE WITH WERE INCLINED TO WAIT ON ISSUING AN
ADVISORY AND THAT/S WHAT I WILL DO AS WELL. STILL...I DO HAVE
WIDESPREAD DENSE FOG IN THE GRIDS AND I/LL HIT IT IN THE HWO.

THAT DEEP LAYER RIDGE REMAINS OVERHEAD ON TUESDAY. WINDS WILL BE
LIGHT AND THE NAM SOUNDINGS ARE SHOWING A PRONOUNCED INVERSION. A
FEW SHRA ARE POSSIBLE ACROSS THE NC MTNS...BUT I/VE PULLED POPS OVER
THE FOOTHILLS AND PIEDMONT. IT WILL BE A MILD DAY WITH NEAR SEASONAL
TEMPERATURES.

&&

.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/...
AS OF 145 PM MONDAY...AVERAGE MODEL AGREEMENT IN THE SHORT
TERM...GIVEN SUBTLE UPPER FEATURES AND OVERALL WEAK FORCING ACRS THE
CWFA. AN UPPER RIDGE WILL BUILD OVER THE EASTERN GREAT LAKES THRU
THE PERIOD...WHILE A WEAK AREA OF LOW PRES WILL LINGER INVOF THE
EASTERN GULF/FL. THIS PATTERN WILL SET UP A DEEP ELY FLOW...WITH AN
INVERTED TROF OFF THE CAROLINA COASTS AND HIGH PRES ANCHORED OVR NEW
ENGLAND WITH A WEDGE SW DOWN THE ENTIRE APPALACHIAN CHAIN. THERE ARE
SUBTLE DIFFERENCES AMONG THE OP MODELS ON A COUPLE OF WEAK WAVES
IN THE LLVL ELY FLOW. OVERALL...THE GFS IS MORE STABLE WITH AN
ATLANTIC MARINE LAYER AND STRONGER WEDGE THAN THE NAM. A LOOK AT THE
STRENGTH OF THE FLOW (850 MB WINDS GENERALLY UNDER 25 KTS) AND LACK
OF UPPER Q-VECTOR CONVERGENCE...I THINK TUESDAY NIGHT AND WEDNESDAY
WILL BE GENERALLY DRY. THE SW NC MTNS LOOK TO HAVE THE MOST INSTBY
AND WITH MTN-TOP CONVERGENCE...MAY HAVE A FEW SHWRS/TSTMS WED AFTN.
OTHERWISE...EXPECTING AN INCREASE IN STRATOCUMULUS BY DAYBREAK
WEDNESDAY...BREAKING UP SOMEWHAT DURING THE DAY. TEMPS WILL BE NEAR
NORMAL FOR LOWS...AND ABOUT A CATEGORY BELOW NORMAL FOR HIGHS.

THERE SEEMS TO BE A CONSENSUS ON A SURGE IN 850-700 MB ATLANTIC
MOISTURE ADVECTING IN...AS FLOW VEERS FROM ENE TO ESE WEDNESDAY
NIGHT INTO THURSDAY (PASSAGE OF AN ELY WAVE). MEANWHILE...A
SUBSIDENCE INVERSION STRENGTHENS IN BOTH THE NAM AND GFS SNDGS ATOP
THE MOIST LAYER. THIS INVERSION SETS UP AROUND 700-600 MB LAYER BY
THURSDAY AFTN. THE NAM AND GFS 295 K SFC BOTH SHOW SOME MOIST
UPGLIDE. PERSISTING FROM ABOUT 06Z THURSDAY TILL 00Z FRIDAY . THAT
ALONG WILL ELY UPSLOPE FLOW ALONG THE BLUE RIDGE SEEMS TO WARRANT
KEEPING A SHOTGUN LOW-END CHC POP EARLY THURSDAY MORNING...THEN
TAPERING OFF IN THE NE HALF OF THE CWFA THURSDAY AFTN...AS DRY AIR
WORKS BACK IN. MIN TEMPS SIMILAR TO TUESDAY NIGHT...BUT EXPECTING
COOLER TEMPS ON THURSDAY AS THICKNESSES FALL UNDER THE WEDGE
(GENERALLY UPR 60S TO LWR 70S).

&&

.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
AS OF 200 PM MONDAY...THE LATEST AVAILABLE MEDIUM RANGE GUIDANCE IS
STILL PROGGING THE CWFA TO BE WITHIN A MOISTURE AND FORCING MINIMA
ON FRIDAY AND IT IS DEBATABLE IF THE LLVL EASTERLY FLOW WILL BE ENUF
TO FORCE ANYTHING MORE THAN A FEW SHOWERS WHICH I DOUBT. MAX TEMPS
ARE SLATED TO BE COOL FOR EARLY MAY...SVRL CATEGORIES BELOW CLIMO.
OMEGA BLOCKING PATTERN CONTINUES INTO THE WEEKEND...AND WITH THE
29/12 UTC OP GFS RUN TO RUN INCONSISTENCY IN HANDLING PLAINS UPPER
LOW MOVEMENT...PREFER TO LEAN TO 29/00 UTC OP ECMWF WITH RESPECT TO
UPPER RIDGE POSITION. BASED ON THIS...WILL PLAN ON ROUGHLY A COOL
PERSISTENCE FCST FOR SATURDAY AND SUNDAY WITH JUST A TOKEN SHOWER
CHANCE EACH DAY WITH TEMPS BY MONDAY GETTING CLOSER TO CLIMO.

&&

.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
AT KCLT...VFR THROUGH THE EVENING WITH A LIGHT WIND FAVORING THE S
OR SW DIRECTION. THE SHOWERS SHOULD STAY CLOSER TO THE BLUE RIDGE OR
OFF TO THE SOUTHEAST. FOR EARLY TUESDAY MORNING...THE MAIN CONCERN
IS THE DEVELOPMENT OF FOG AND LOW STRATUS. THE LATEST LAMP GUIDANCE
HAS BACKED OFF ON THE LOW IFR CONDITION AND THE 15Z SREF HAS VERY
LOW PROBABILITY OF IFR VISIBILITY...WHICH HAS REDUCED CONFIDENCE IN
DENSE FOG. HAVE OPTED TO IMPROVE THE FCST FROM LOW IFR TO MERELY IFR
DEVELOPING AROUND 08Z AND PERSISTING PAST SUNRISE. THERE SHOULD BE A
PERIOD OF AN HOUR OR TWO WHERE THE CLOUDS LIFT TO MVFR BEFORE
SCATTERING OUT. CLOUD BASES SHOULD CONTINUE TO RISE ABOVE 030
THROUGH AFTERNOON. EXPECT WIND TO COME AROUND TO NE MIDDAY AND
REMAIN THAT WAY THROUGH THE END OF THE PERIOD.

ELSEWHERE...SIMILAR THINKING...ALTHOUGH PERHAPS A BETTER CHANCE OF
CEILING AND VIS DROPPING DOWN TO LIFR OR VLIFR.

OUTLOOK...EARLY MORNING LOW CLOUDS AND FOG...WITH A SMALL CHANCE OF
AFTERNOON SHOWERS/THUNDERSTORMS EACH DAY THROUGH AT LEAST FRIDAY

CONFIDENCE TABLE...

            00-06Z        06-12Z        12-18Z        18-24Z
KCLT       HIGH  87%     HIGH  81%     HIGH  81%     HIGH  80%
KGSP       HIGH  94%     MED   66%     HIGH  84%     HIGH 100%
KAVL       HIGH  89%     MED   78%     HIGH  85%     HIGH 100%
KHKY       HIGH  87%     MED   74%     HIGH  82%     MED   79%
KGMU       HIGH  98%     MED   65%     MED   78%     HIGH 100%
KAND       HIGH 100%     HIGH  82%     HIGH  90%     HIGH 100%

THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)

WWW.WEATHER.GOV/GSP/AVIATION_TABLES

&&

.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.

&&

$$
SYNOPSIS...CSH
NEAR TERM...MCAVOY/PM
SHORT TERM...ARK
LONG TERM...CSH
AVIATION...PM







AREA FORECAST DISCUSSION

NWS GREENVILLE-SPARTANBURG SC

 258 PM EDT SUN APR 28 2013

.SYNOPSIS...
A NEARBY FRONT WILL DISSIPATE EARLY THIS WEEK AS DRIER AIR MOVES IN
FROM THE WEST. A RIDGE OF HIGH PRESSURE WILL THEN STRENGTHEN ACROSS
THE AREA BY MID-WEEK. A CLOSED OFF UPPER LOW OVER THE MID
MISSISSIPPI VALLEY LATE IN THE WEEK IS EXPECTED TO BRING MORE
UNSETTLED WEATHER TO OUR REGION.

&&

.NEAR TERM /THROUGH MONDAY/...
AS OF 255 PM...KFFC STORM TRACK INFO CONTINUES TO SHOW NUMEROUS
CELLS ACROSS AL/NRN GA...TRACKING TOWARD THE WESTERN CAROLINAS. SPC
MESOANALYSIS TRENDS AND RAP INDICATE A FIELD OF WEAK CAPE VALUES
WILL SPREAD NORTH ALONG THE BORDER OF CAD THIS AFTERNOON...MAINLY
EAST OF I-85 AND ACROSS THE TN BORDER OF THE NC MTNS. THE NOSE OF
THE CAD MAY EXTEND ACROSS NE GA. HOWEVER...LATEST SATELLITE BLENDED
TOTAL PRECIP WATER CONTINUED TO INDICATE A PLUME OF 1.1 TO 1.2 INCHES
ACROSS THE WESTERN CWA...OR AROUND 170 PERCENT OF NORMAL. SATELLITE
WATER VAPOR INDICATES A CONNECTION AS FAR SOUTH AS NRN MEXICO. THIS
RICH MOISTURE ENVIRONMENT WILL LIKELY REMAIN AHEAD OF AN APPROACHING
H5 TROF. IN ADDITION...THE FORECAST AREA SHOULD REMAIN UNDER A
RIBBON OF JET DIVERGENCE...ASSOCIATED WITH A JET EAST OF THE CLOSED
LOW OVER THE OHIO RIVER VALLEY. THE BROAD UPPER LEVEL FORCING
COMBINED WITH DEEP MOISTURE AND LIMITED INSTABILITY SHOULD PROVIDE A
SUPPORTIVE ENVIRONMENT OF MODERATE SHOWERS AND EMBEDDED TSRA ACROSS
THE WESTERN CAROLINAS AND NE GA THROUGH MID EVENING.

CONVECTION ALLOWING MODELS...CAMS...INDICATE THAT THE BEST WINDOW
FOR TSRA WILL OCCUR LATER THIS AFTERNOON INTO EARLY THIS
EVENING...RESULTING FROM THE GREATEST OVERLAP OF UPPER SUPPORT AND
INSTABILITY. THIS WILL BE PRIME TIME FOR THE HIGHEST RAINFALL
RATES...INCREASING THE POTENTIAL FOR FLASH FLOODING. ONE HOUR FFG
RANGES FROM 1.5 TO 2.5 INCHES ACROSS THE FORECAST AREA. SOCIAL MEDIA
REPORTS...AUTOMATED RAIN GAUGES...AND RADAR RAINFALL ESTIMATES
INDICATE THE GREATEST RAINFALL AMOUNTS SO FAR TODAY REMAIN OVER THE
SOUTHERN AND CENTRAL NC MTNS WITH ANOTHER SWATH ACROSS EXTREME NE
GA...AMOUNTS FROM 1.5 TO 2.5 INCHES. IT IS INTERESTING THAT THE CAMS
SPREAD DEEP CONVECTION ACROSS THE I-85 CORRIDOR...INCLUDING THE CLT
METRO AREA EARLY THIS EVENING. HOWEVER...THE LINEAR APPEARANCE TO
THE CONVECTION SUGGEST THAT THE MOTION WILL BE HIGH ENOUGH TO NOT
SUPPORT AN EXPANSION IN THE FFA.

THE COVERAGE OF RAINFALL SHOULD BEGIN TO DECREASE FROM WEST TO EAST
EARLY MON MORNING WITH THE ARRIVAL OF THE MID LEVEL TROF. AT THE
SFC...A COMPLEX COMBINATION OF THE WEDGE BOUNDARY AND WEAK COLD
FRONT WILL MAKE THE TEMPERATURE CHALLENGING. HOWEVER...THE COOL
CURRENT TEMPERATURES WILL LIKE POSITION TEMPERATURES TO RISE
OVERNIGHT AS CAD ERODES. IN ADDITION...CONDITIONS WILL FEATURE LOW
CLOUDS AND FOG OVERNIGHT. ON MONDAY...CLOUD COVER WILL CONTINUE TO
DECREASE...ALLOWING SOME BREAKS. MESOSCALE MODELS INDICATE A BAND OF
WEAK CAPE WILL DEVELOP ACROSS THE FOOTHILLS DURING THE AFTERNOON.
THE BAND OF CAPE ALONG AND EAST OF WEAK COLD FRONT MAY SUPPORT
ANOTHER BAND OF SHRA...POSSIBLY TSRA DURING THE AFTERNOON. HIGHS ARE
FORECAST TO PEAK 3 TO 5 DEGREES BELOW NORMAL.

&&

.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY/...
AS OF 230 PM EDT SUNDAY...AN H5 RIDGE WILL BUILD OVER THE ERN CONUS
ON TUE...BUT WITH LOW PRESSURE PERSISTING UNDER THE RIDGE NEAR THE
WRN GULF COAST. LOW LEVELS WILL REMAIN FAIRLY MOIST ACROSS THE
REGION...AND MORNING LOW CLOUDS/FOG LOOK LIKE A GOOD BET LATE MON
NIGHT/TUE MORNING. AFTER SOME BRIEF SCATTERING...A RETURN TO LIGHT
SE UPSLOPE FLOW WILL BRING CLOUDS BACK TO THE AREA BY LATER IN THE
DAY. PROFILES EXIHIBIT SOME CAPPING ON TUE...BUT THIS MIGHT BE
OVERCOME BY LATE AFTN. WILL FEATURE ISOLD AFTN CONVECTIVE
COVERAGE...ESPECIALLY NEAR THE ERN ESCARPMENT...WITH TEMPERATURES
WARMING TO NEAR CLIMATE NORMALS THROUGHOUT.

ANOTHER ROUND OF LOW CLOUDS/FOG ARE EXPECTED LATE TUE NIGHT/WED
MORNING. THERE IS CONSIDERABLE UNCERTAINTY OVER HOW FAR EAST THE
GULF COAST LOW PRES SYSTEM GETS BY WED...BUT THE EASTERLY ATLANTIC
FETCH AROUND HIGH PRES OVER THE NE U.S. WILL DEEPEN LOW LEVEL
MOISTURE THROUGH WED IN ANY CASE. LESS CAPPING AND MORE MOISTURE IS
EXHIBITED IN PROFILES ON WED...ALONG WITH BETTER TRIGGERING EASTERLY
UPSLOPE FLOW. WILL FEATURE SLIGHTLY MORE ROBUST CHC AFTN POPS WITH
TEMPS TRIMMED A DEGREE OR TWO BELOW TUE MAXES.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
AS OF 225 PM SUNDAY...THE MEDIUM RANGE MODELS ARE IN BETTER
AGREEMENT FOR LATE IN THE WEEK AND THROUGH THE START OF NEXT WEEK.
THIS PERIOD BEGINS AT 00Z THURSDAY WITH A SHARP 500MB RIDGE OVER THE
EAST COAST AS A TROUGH DIGS SOUTH OVER THE PLAINS STATES. THE ECMWF
HAS BEEN THE DRIER OF THE MODELS LATE IN THE WEEK FOR THE EAST COAST
WITH THE RIDGE HOLDING FROM THE CAROLINAS NORTH. THIS RIDGE SHOULD
HOLD FOR OUR AREA FROM WEDNESDAY NIGHT THROUGH EARLY FRIDAY AND
KEEPING POPS AT SLIGHT OR LOW CHANCE AT BEST. THIS SHARP DIP IN THE
UPPER FLOW IS FORECAST TO GET PINCHED OFF THURSDAY NIGHT AND BECOME
A CLOSED LOW SOMEWHERE OVER THE MID SECTION OF THE NATION.  SURFACE
LOWS ARE EXPECTED TO FORM ALONG A BOUNDARY EXTENDING NORTH FROM THE
GULF THURSDAY NIGHT INTO FRIDAY BUT THIS WILL PRIMARILY AFFECT
LOCATIONS WEST OF THE CAROLINA AND GEORGIA MOUNTAINS. THIS BOUNDARY
WILL MOVE EAST AND THE MODELS ARE IN FAIRLY GOOD AGREEMENT THAT THIS
WILL SLOWLY CROSS OUR AREA FRIDAY NIGHT THROUGH SATURDAY. LOW LEVEL
FLOW WILL GO FROM A ENE DIRECTION TO A SE UPSLOPE FLOW FRIDAY NIGHT
AND EARLY SATURDAY ALONG THE BLUE RIDGE ESCARPMENT ENHANCING
RAINFALL FOR THE SRN MTNS AND FOOTHILLS. GFS HAS 30 TO 35 KT 925MB
FLOW FROM THE SE EARLY SATURDAY WITH A WEST TO NORTH 10 TO 20 KT
FLOW OVER GA AND TN ATTM. GFS HAS CAPE VALUES REACHING 300 TO 500
OVER THE UPPER SAVANNAH VALLEY EARLY SATURDAY AFTERNOON. AS THE
UPPER LOW LINGERS OVER IOWA LATE IN THE WEEKEND...THE FRONTAL
BOUNDARY EXTENDING FROM THE CAROLINAS TO THE GREAT LAKES WILL LINGER
NEAR THE SAME AREA INTO SUNDAY NIGHT. DAY TIME HIGHS WILL BE BELOW
NORMAL THROUGH THE PERIOD AND LOWS NEAR NORMAL.

&&

.AVIATION /19Z SUNDAY THROUGH FRIDAY/...
AT KCLT AND ELSEWHERE...WESTERN CAROLINA TERMINALS APPEAR WITHIN THE
REGION OF CAD...THEREFORE...THE AREA OF IFR TO LIFR CEILINGS. CLT
REMAINS ON THE VERY EDGE OF THE CAD BOUNDARY. HOWEVER...THE CURRENT
AREA OF MODERATE RAIN ACROSS THE CLT TERMINAL SHOULD REINFORCE THE
CAD...FORCING THE BOUNDARY FURTHER EAST. NO GUIDANCE HANDLES THE
POSITION WELL...BUT WRF INDICATED THAT A SIMILAR BOUNDARY SHIFT
WOULD OCCUR LATER TODAY. I WILL KEEP CLT IN THE WEDGE CLOUDS THROUGH
SUNSET. AFTER SUNSET...ALL GUIDANCE INDICATES WIDESPREAD IFR TO LIFR
CLOUDS WILL CONTINUE OVERNIGHT. CONVECTION ALLOWING MODELS TIME A
LINE OF SHRA/TSRA ACROSS THE WESTERN CAROLINAS EARLY THIS
EVENING...I WILL INDICATE A VCTS...TEMPO...OR PROB30 FOR THE PERIOD
OF GREATEST TSRA RISK. AFTER SUNRISE MONDAY...DOWNSLOPING WINDS
SHOULD RESULT IN A WEST TO EAST RETURN TO VFR CLOUDS WITH P6SM.

OUTLOOK...AN UPPER LEVEL WAVE WILL CROSS THE REGION ON
MONDAY...ACCOMPANIED BY SCATTERED THUNDERSTORMS AND ASSOCIATED
RESTRICTIONS. LOW CLOUDS AND FOG WILL THEN BE POSSIBLE EACH MORNING
THROUGH MID WEEK.

CONFIDENCE TABLE...

            19-01Z        01-07Z        07-13Z        13-19Z
KCLT       HIGH  83%     MED   79%     MED   65%     HIGH  92%
KGSP       MED   78%     MED   72%     MED   70%     HIGH  95%
KAVL       HIGH 100%     HIGH  94%     HIGH  86%     HIGH  86%
KHKY       MED   78%     HIGH  81%     HIGH  83%     HIGH  97%
KGMU       HIGH  84%     HIGH  84%     MED   62%     HIGH  93%
KAND       HIGH  86%     MED   61%     MED   66%     HIGH  95%

THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)

WWW.WEATHER.GOV/GSP/AVIATION_TABLES

&&

.GSP WATCHES/WARNINGS/ADVISORIES...
GA...FLASH FLOOD WATCH UNTIL 8 PM EDT THIS EVENING FOR GAZ010-017-
     018.
NC...FLASH FLOOD WATCH UNTIL 8 PM EDT THIS EVENING FOR NCZ048-
     051>053-058-059-062>065-507-509-510.
SC...FLASH FLOOD WATCH UNTIL 8 PM EDT THIS EVENING FOR SCZ001>007.

&&

$$
SYNOPSIS...DEO
NEAR TERM...NED
SHORT TERM...HG
LONG TERM...DEO
AVIATION...NED







AREA FORECAST DISCUSSION

NWS GREENVILLE-SPARTANBURG SC

 211 PM EDT SUN APR 28 2013

.SYNOPSIS...
A NEARBY FRONT WILL DISSIPATE EARLY THIS WEEK AS DRIER AIR MOVES IN
FROM THE WEST. A RIDGE OF HIGH PRESSURE WILL THEN STRENGTHEN ACROSS
THE AREA BY MID-WEEK. A CLOSED OFF UPPER LOW OVER THE MID
MISSISSIPPI VALLEY LATE IN THE WEEK IS EXPECTED TO BRING MORE
UNSETTLED WEATHER TO OUR REGION.

&&

.NEAR TERM /THROUGH TONIGHT/...
AS OF 1230 PM...LATEST SATELLITE BLENDED TOTAL PRECIP WATER
INDICATED A PLUME OF 1.1 TO 1.2 INCHES ACROSS THE WESTERN CWA...OR
AROUND 170 PERCENT OF NORMAL. SATELLITE WATER VAPOR INDICATES A
CONNECTION AS FAR SOUTH AS NRN MEXICO. THIS RICH MOISTURE
ENVIRONMENT WILL LIKELY REMAIN AHEAD OF AN APPROACHING H5 TROF. IN
ADDITION...THE FORECAST AREA SHOULD REMAIN UNDER A RIBBON OF JET
DIVERGENCE...ASSOCIATED WITH A JET EAST OF THE CLOSED LOW OVER THE
OHIO RIVER VALLEY. THE BROAD UPPER LEVEL SUPPORT COMBINED WITH LLVL
UPSLOPE FLOW AND ISENTROPIC LIFT HAS SUPPORTED A WIDE BAND OF RAIN
AND EMBEDDED TSRA ACROSS THE MTNS AND FOOTHILLS THIS MORNING.
HOWEVER...SPC MESOANALYSIS TRENDS AND RAP INDICATE A FIELD OF WEAK
CAPE VALUES WILL SPREAD NORTH ALONG THE BORDER OF CAD THIS
AFTERNOON...MAINLY EAST OF I-85 AND ACROSS THE TN BORDER OF THE NC
MTNS. THE INCREASE IN CONDITIONAL INSTABILITY SHOULD RESULT IN
GREATER TSRA COVERAGE. CONVECTION ALLOWING MODELS...CAMS...INDICATE
THAT THE BEST WINDOW FOR TSRA WILL OCCUR LATE THIS AFTERNOON INTO
EARLY THIS EVENING...RESULTING FROM THE GREATEST OVERLAP OF UPPER
SUPPORT AND INSTABILITY. THIS WILL BE PRIME TIME FOR THE HIGHEST
RAINFALL RATES...INCREASING THE POTENTIAL FOR FLASH FLOODING. IT IS
INTERESTING THAT THE CAMS SPREAD DEEP CONVECTION ACROSS THE CLT
METRO AREA EARLY THIS EVENING. HOWEVER...THE LINEAR APPEARANCE TO
THE CONVECTION SUGGEST THAT THE MOTION WILL BE HIGH ENOUGH TO NOT
SUPPORT AN EXPANSION IN THE FFA.

I WILL UPDATE THE FORECAST TO LIMIT ANY ADDITIONAL HEATING ACROSS
THE MTNS AND FOOTHILLS THIS AFTERNOON. I HAVE ALSO INCREASE QPF
ACROSS THE MTNS AND FOOTHILLS INTO THE EARLY EVENING.

AS OF 945 AM...I HAVE MADE SIGNIFICANT CHANGES TO THE FORECAST TO
ACCOUNT FOR EXPECTED HEAVY QPF AND TSRA ACROSS THE WESTERN CAROLINAS
AND NE GA TODAY. REGIONAL RADAR INDICATES A WIDE BAND OF SHRA AND
TSRA ACROSS THE SOUTHERN AND CENTRAL NC MTNS...SW TO AL. FFC STI
INDICATES UNIFORM MOTION OF CELL NE ACROSS GA AND SOUTHERN
TN...REACH THE CAROLINA MTNS AND NE GA THROUGH EARLY EVENING. THE
ATMOSPHERE FEATURE PW VALUES NEAR 200 PERCENT OF NORMAL...SOURCED
FROM THE GULF. AS A MID LEVEL TROF APPROACHES THIS AFTERNOON...LIFT
AND INSTABILITY WILL INCREASE...SUPPORTING ANOTHER BAND OF TSRA TO
CROSS THE REGION. FFG ACROSS THE MTNS IS GENERALLY LOW...1.5 TO 2
INCHES PER HOUR. I WILL ISSUE A FLASH FLOOD WATCH FOR EXTREME NE
GA...THE CENTRAL AND SOUTHERN NC MTNS...AND AREAS NORTH OF I-85
ACROSS THE UPSTATE OF SC UNTIL 8 PM.

&&

.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AS OF 200 AM SUNDAY...BASED UPON THE LATEST MODEL GUIDANCE...
CONFIDENCE IS INCREASING THAT THE WEAKENING UPPER TROUGH AXIS WILL
SHIFT INTO THE MID-ATLANTIC ON MONDAY...TAKING THE DEEPER MOISTURE
AND FORCING ALONG WITH IT. LIKELY POPS WILL LINGER ACROSS THE
EASTERN ZONES AT THE START OF THE PERIOD...BUT SYNOPTICALLY FORCED
PRECIP SHOULD BE EAST OF THE AREA BY AFTERNOON. HOWEVER...THE LOWER
LEVELS WILL REMAIN MOIST. IN FACT...WITH THE DRYING MID/UPPER
LEVELS...WARMER TEMPS AND IMPROVED INSTABILITY ARE EXPECTED MONDAY
AFTERNOON. THIS IS SHOULD RESULT IN DEVELOPMENT OF SCATTERED
CONVECTION...PARTICULARLY OVER THE MTNS...AND CHANCE POPS WILL BE
CARRIED THROUGH THE AFTERNOON AND EVENING.

BY TUESDAY...STRONG HEIGHT FALLS OVER THE WESTERN CONUS WILL ACT TO
BUILD THE DOWNSTREAM RIDGE. THIS WILL STRENGTHEN THE SURFACE HIGH
OVER THE CANADIAN MARITIMES AND SHARPEN THE RIDGE FROM THE MID-
ATLANTIC INTO THE CAROLINAS. A DRIER LOW LEVEL AIR MASS WILL ADVECT
AT LEAST AS FAR SOUTH/WEST AS THE MID-ATLANTIC. HOWEVER...IT IS
INCONCLUSIVE AS TO WHETHER THIS DRIER AIR WILL PENETRATE AS FAR
SOUTH AS THE WESTERN CAROLINAS. IN FACT...THE GFS KEEPS CONDITIONS
QUITE MOIST DURING THIS TIME. THEREFORE...WE WILL MAINTAIN SMALL/
MAINLY DIURNAL POPS THROUGH THE END OF THE PERIOD.

&&

.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
AS OF 215 AM SUNDAY...THE GLOBAL MODELS ARE CONVERGING TOWARD
AGREEMENT IN ESTABLISHMENT OF AN OMEGA BLOCKING PATTERN DURING THE
MEDIUM RANGE...WITH LOW PRESSURE LIKELY SETTLING SOMEWHERE IN THE
CENTRAL CONUS. IF ANYTHING...THE MODELS ARE SIGNALING THAT THE
SURFACE HIGH WILL GRADUALLY BUILD FARTHER SOUTH ALONG THE EAST
COAST...ALLOWING A DRYING LOW LEVEL AIR MASS TO FILTER INTO THE
SOUTHEAST. BASED UPON THIS...OUR CURRENT POP FORECAST APPEARS TOO
PESSIMISTIC DURING THE LATTER HALF OF THE WEEK. WE HAVE BEGUN THE
PROCESS OF BACKING AWAY FROM HIGHER POPS...BUT WILL WAIT UNTIL A
CLEAR TREND BECOMES ESTABLISHED IN GUIDANCE BEFORE MAKING MORE
DRAMATIC CHANGES.

&&

.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
AT KCLT AND ELSEWHERE...WESTERN CAROLINA TERMINALS APPEAR WITHIN THE
REGION OF CAD...THEREFORE...THE AREA OF IFR TO LIFR CEILINGS. CLT
REMAINS ON THE VERY EDGE OF THE CAD BOUNDARY. HOWEVER...THE CURRENT
AREA OF MODERATE RAIN ACROSS THE CLT TERMINAL SHOULD REINFORCE THE
CAD...FORCING THE BOUNDARY FURTHER EAST. NO GUIDANCE HANDLES THE
POSITION WELL...BUT WRF INDICATED THAT A SIMILAR BOUNDARY SHIFT
WOULD OCCUR LATER TODAY. I WILL KEEP CLT IN THE WEDGE CLOUDS THROUGH
SUNSET. AFTER SUNSET...ALL GUIDANCE INDICATES WIDESPREAD IFR TO LIFR
CLOUDS WILL CONTINUE OVERNIGHT. CONVECTION ALLOWING MODELS TIME A
LINE OF SHRA/TSRA ACROSS THE WESTERN CAROLINAS EARLY THIS
EVENING...I WILL INDICATE A VCTS...TEMPO...OR PROB30 FOR THE PERIOD
OF GREATEST TSRA RISK. AFTER SUNRISE MONDAY...DOWNSLOPING WINDS
SHOULD RESULT IN A WEST TO EAST RETURN TO VFR CLOUDS WITH P6SM.

OUTLOOK...AN UPPER LEVEL WAVE WILL CROSS THE REGION ON
MONDAY...ACCOMPANIED BY SCATTERED THUNDERSTORMS AND ASSOCIATED
RESTRICTIONS. LOW CLOUDS AND FOG WILL THEN BE POSSIBLE EACH MORNING
THROUGH MID WEEK.

CONFIDENCE TABLE...

            18-24Z        00-06Z        06-12Z        12-18Z
KCLT       MED   77%     HIGH  80%     MED   73%     HIGH  94%
KGSP       MED   78%     MED   78%     MED   70%     HIGH  95%
KAVL       HIGH 100%     HIGH  96%     HIGH  83%     HIGH  90%
KHKY       MED   77%     HIGH  82%     HIGH  81%     HIGH  95%
KGMU       HIGH  84%     HIGH  88%     MED   66%     HIGH  95%
KAND       HIGH  96%     MED   77%     MED   79%     HIGH  93%

THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)

WWW.WEATHER.GOV/GSP/AVIATION_TABLES

&&

.GSP WATCHES/WARNINGS/ADVISORIES...
GA...FLASH FLOOD WATCH UNTIL 8 PM EDT THIS EVENING FOR GAZ010-017-
     018.
NC...FLASH FLOOD WATCH UNTIL 8 PM EDT THIS EVENING FOR NCZ048-
     051>053-058-059-062>065-507-509-510.
SC...FLASH FLOOD WATCH UNTIL 8 PM EDT THIS EVENING FOR SCZ001>007.

&&

$$
SYNOPSIS...JDL
NEAR TERM...NED
SHORT TERM...JDL
LONG TERM...JDL
AVIATION...NED







AREA FORECAST DISCUSSION

NWS GREENVILLE-SPARTANBURG SC

 1237 PM EDT SUN APR 28 2013

.SYNOPSIS...
A NEARBY FRONT WILL DISSIPATE EARLY THIS WEEK AS DRIER AIR MOVES IN
FROM THE WEST. A RIDGE OF HIGH PRESSURE WILL THEN STRENGTHEN ACROSS
THE AREA BY MID-WEEK. A CLOSED OFF UPPER LOW OVER THE MID
MISSISSIPPI VALLEY LATE IN THE WEEK IS EXPECTED TO BRING MORE
UNSETTLED WEATHER TO OUR REGION.

&&

.NEAR TERM /THROUGH TONIGHT/...
AS OF 1230 PM...LATEST SATELLITE BLENDED TOTAL PRECIP WATER
INDICATED A PLUME OF 1.1 TO 1.2 INCHES ACROSS THE WESTERN CWA...OR
AROUND 170 PERCENT OF NORMAL. SATELLITE WATER VAPOR INDICATES A
CONNECTION AS FAR SOUTH AS NRN MEXICO. THIS RICH MOISTURE
ENVIRONMENT WILL LIKELY REMAIN AHEAD OF AN APPROACHING H5 TROF. IN
ADDITION...THE FORECAST AREA SHOULD REMAIN UNDER A RIBBON OF JET
DIVERGENCE...ASSOCIATED WITH A JET EAST OF THE CLOSED LOW OVER THE
OHIO RIVER VALLEY. THE BROAD UPPER LEVEL SUPPORT COMBINED WITH LLVL
UPSLOPE FLOW AND ISENTROPIC LIFT HAS SUPPORTED A WIDE BAND OF RAIN
AND EMBEDDED TSRA ACROSS THE MTNS AND FOOTHILLS THIS MORNING.
HOWEVER...SPC MESOANALYSIS TRENDS AND RAP INDICATE A FIELD OF WEAK
CAPE VALUES WILL SPREAD NORTH ALONG THE BORDER OF CAD THIS
AFTERNOON...MAINLY EAST OF I-85 AND ACROSS THE TN BORDER OF THE NC
MTNS. THE INCREASE IN CONDITIONAL INSTABILITY SHOULD RESULT IN
GREATER TSRA COVERAGE. CONVECTION ALLOWING MODELS...CAMS...INDICATE
THAT THE BEST WINDOW FOR TSRA WILL OCCUR LATE THIS AFTERNOON INTO
EARLY THIS EVENING...RESULTING FROM THE GREATEST OVERLAP OF UPPER
SUPPORT AND INSTABILITY. THIS WILL BE PRIME TIME FOR THE HIGHEST
RAINFALL RATES...INCREASING THE POTENTIAL FOR FLASH FLOODING. IT IS
INTERESTING THAT THE CAMS SPREAD DEEP CONVECTION ACROSS THE CLT
METRO AREA EARLY THIS EVENING. HOWEVER...THE LINEAR APPEARANCE TO
THE CONVECTION SUGGEST THAT THE MOTION WILL BE HIGH ENOUGH TO NOT
SUPPORT AN EXPANSION IN THE FFA.

I WILL UPDATE THE FORECAST TO LIMIT ANY ADDITIONAL HEATING ACROSS
THE MTNS AND FOOTHILLS THIS AFTERNOON. I HAVE ALSO INCREASE QPF
ACROSS THE MTNS AND FOOTHILLS INTO THE EARLY EVENING.

AS OF 945 AM...I HAVE MADE SIGNIFICANT CHANGES TO THE FORECAST TO
ACCOUNT FOR EXPECTED HEAVY QPF AND TSRA ACROSS THE WESTERN CAROLINAS
AND NE GA TODAY. REGIONAL RADAR INDICATES A WIDE BAND OF SHRA AND
TSRA ACROSS THE SOUTHERN AND CENTRAL NC MTNS...SW TO AL. FFC STI
INDICATES UNIFORM MOTION OF CELL NE ACROSS GA AND SOUTHERN
TN...REACH THE CAROLINA MTNS AND NE GA THROUGH EARLY EVENING. THE
ATMOSPHERE FEATURE PW VALUES NEAR 200 PERCENT OF NORMAL...SOURCED
FROM THE GULF. AS A MID LEVEL TROF APPROACHES THIS AFTERNOON...LIFT
AND INSTABILITY WILL INCREASE...SUPPORTING ANOTHER BAND OF TSRA TO
CROSS THE REGION. FFG ACROSS THE MTNS IS GENERALLY LOW...1.5 TO 2
INCHES PER HOUR. I WILL ISSUE A FLASH FLOOD WATCH FOR EXTREME NE
GA...THE CENTRAL AND SOUTHERN NC MTNS...AND AREAS NORTH OF I-85
ACROSS THE UPSTATE OF SC UNTIL 8 PM.

&&

.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AS OF 200 AM SUNDAY...BASED UPON THE LATEST MODEL GUIDANCE...
CONFIDENCE IS INCREASING THAT THE WEAKENING UPPER TROUGH AXIS WILL
SHIFT INTO THE MID-ATLANTIC ON MONDAY...TAKING THE DEEPER MOISTURE
AND FORCING ALONG WITH IT. LIKELY POPS WILL LINGER ACROSS THE
EASTERN ZONES AT THE START OF THE PERIOD...BUT SYNOPTICALLY FORCED
PRECIP SHOULD BE EAST OF THE AREA BY AFTERNOON. HOWEVER...THE LOWER
LEVELS WILL REMAIN MOIST. IN FACT...WITH THE DRYING MID/UPPER
LEVELS...WARMER TEMPS AND IMPROVED INSTABILITY ARE EXPECTED MONDAY
AFTERNOON. THIS IS SHOULD RESULT IN DEVELOPMENT OF SCATTERED
CONVECTION...PARTICULARLY OVER THE MTNS...AND CHANCE POPS WILL BE
CARRIED THROUGH THE AFTERNOON AND EVENING.

BY TUESDAY...STRONG HEIGHT FALLS OVER THE WESTERN CONUS WILL ACT TO
BUILD THE DOWNSTREAM RIDGE. THIS WILL STRENGTHEN THE SURFACE HIGH
OVER THE CANADIAN MARITIMES AND SHARPEN THE RIDGE FROM THE MID-
ATLANTIC INTO THE CAROLINAS. A DRIER LOW LEVEL AIR MASS WILL ADVECT
AT LEAST AS FAR SOUTH/WEST AS THE MID-ATLANTIC. HOWEVER...IT IS
INCONCLUSIVE AS TO WHETHER THIS DRIER AIR WILL PENETRATE AS FAR
SOUTH AS THE WESTERN CAROLINAS. IN FACT...THE GFS KEEPS CONDITIONS
QUITE MOIST DURING THIS TIME. THEREFORE...WE WILL MAINTAIN SMALL/
MAINLY DIURNAL POPS THROUGH THE END OF THE PERIOD.

&&

.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
AS OF 215 AM SUNDAY...THE GLOBAL MODELS ARE CONVERGING TOWARD
AGREEMENT IN ESTABLISHMENT OF AN OMEGA BLOCKING PATTERN DURING THE
MEDIUM RANGE...WITH LOW PRESSURE LIKELY SETTLING SOMEWHERE IN THE
CENTRAL CONUS. IF ANYTHING...THE MODELS ARE SIGNALING THAT THE
SURFACE HIGH WILL GRADUALLY BUILD FARTHER SOUTH ALONG THE EAST
COAST...ALLOWING A DRYING LOW LEVEL AIR MASS TO FILTER INTO THE
SOUTHEAST. BASED UPON THIS...OUR CURRENT POP FORECAST APPEARS TOO
PESSIMISTIC DURING THE LATTER HALF OF THE WEEK. WE HAVE BEGUN THE
PROCESS OF BACKING AWAY FROM HIGHER POPS...BUT WILL WAIT UNTIL A
CLEAR TREND BECOMES ESTABLISHED IN GUIDANCE BEFORE MAKING MORE
DRAMATIC CHANGES.

&&

.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
AT KCLT...COLD WEDGE IN CONTROL FOR TODAY AND SHOULD BE ABLE TO
MAINTAIN ESE TO SE WINDS INTO THE EVENING. INCREASING WARM FLOW OVER
THE WEDGE IN CONJUNCTION WITH UPPER FORCING WILL LEAD TO
INCREASINGLY WIDESPREAD SHOWERS. AVBL GUIDANCE HAS BEEN GENERALLY
POOR WRT CIG HEIGHTS SO FAR THIS MRNG...BUT GIVEN UPSTREAM ACTIVITY
HAVE CAPPED GUIDANCE BLEND AT MVFR. SOME FEATURES WILL BE IN PLACE
TO ERODE THE WEDGE AS THE DAY PROGRESSES. HOWEVER GIVEN THE
CONTINUING PRECIP WILL ASSUME LATER GUIDANCE FOR EROSION TIMING.
SOME INSTABILITY TO CREEP IN AS THE WEDGE RETREATS AFTER SUNSET.
HENCE PROB30S FOR TSRA LATE TONIGHT.

ELSEWHERE...AHEAD OF PROMINENT UPPER SHORTWAVE TROUGH MIDLEVEL WINDS
WILL RAMP UP THIS MORNING OVER AFOREMENTIONED WEDGE. PRECIP
GENERALLY EXPECTED TO DROP VSBY ONLY TO MVFR...WITH CIG GUIDANCE
FAVORING IFR. HOWEVER GIVEN POOR EARLY MRNG PERFORMANCE AND UPSTREAM
OBS MVFR LOOKS LIKE A GOOD BET FOR TODAY. RESTRICTIONS ARE LIKELY TO
CONTINUE THRU THE PERIOD EVEN AFTER WEDGE DIMINISHES TONIGHT...WITH
LLVL MSTR PROFILES STAYING SATURATED. CURRENTLY EXPECT MOST SITES TO
HIT IFR THRESHOLD AFTER 00Z MON. THUNDER ALSO POSSIBLE EARLY THIS
MORNING NEAR THE TENN BORDER WITH INCOMING CONVECTIVE LINE...THOUGH
+RA AND LIGHTNING ARE THE ONLY THREATS. THUNDER MAY RETURN LATE THIS
AFTERNOON AND TONIGHT IN THE PIEDMONT WITH INSTABILITY POTENTIALLY
BEING REALIZED IN THE WAKE OF THE WEDGE.

OUTLOOK...AN UPPER LEVEL WAVE WILL CROSS THE REGION ON
MONDAY...ACCOMPANIED BY SCATTERED THUNDERSTORMS AND ASSOCIATED
RESTRICTIONS. LOW CLOUDS AND FOG WILL THEN BE POSSIBLE EACH MORNING
THROUGH MID WEEK.

CONFIDENCE TABLE...

            16-22Z        22-04Z        04-10Z        10-16Z
KCLT       HIGH  80%     MED   77%     LOW   55%     MED   63%
KGSP       HIGH  95%     MED   63%     MED   68%     MED   74%
KAVL       HIGH 100%     MED   60%     LOW   59%     LOW   50%
KHKY       HIGH 100%     HIGH  96%     LOW   57%     LOW   58%
KGMU       HIGH  83%     LOW   40%     MED   68%     MED   63%
KAND       LOW   57%     LOW   42%     HIGH  87%     HIGH  88%

THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)

WWW.WEATHER.GOV/GSP/AVIATION_TABLES

&&

.GSP WATCHES/WARNINGS/ADVISORIES...
GA...FLASH FLOOD WATCH UNTIL 8 PM EDT THIS EVENING FOR GAZ010-017-
     018.
NC...FLASH FLOOD WATCH UNTIL 8 PM EDT THIS EVENING FOR NCZ048-
     051>053-058-059-062>065-507-509-510.
SC...FLASH FLOOD WATCH UNTIL 8 PM EDT THIS EVENING FOR SCZ001>007.

&&

$$
SYNOPSIS...JDL
NEAR TERM...NED
SHORT TERM...JDL
LONG TERM...JDL
AVIATION...WIMBERLEY







AREA FORECAST DISCUSSION

NWS GREENVILLE-SPARTANBURG SC

 201 AM EDT SUN APR 28 2013

.SYNOPSIS...
A MOIST WEDGE OF COOLER AIR WILL REMAIN OVER THE REGION FOR MOST OF
TODAY AS WEAK LOW PRESSURE MOVES ACROSS THE TENNESSEE VALLEY ALONG A
STALLED COLD FRONT. THE FRONT WILL SLOWLY DISSIPATE AND THE COOL AIR
WEDGE WILL GRADUALLY WEAKEN BY TONIGHT. OUR WEATHER PATTERN WILL
LIKELY REMAIN UNSETTLED THROUGH NEXT WEEKEND.

&&

.NEAR TERM /THROUGH TODAY/...
1 AM UPDATE...REVISED THE FIRST FEW HOURS OF POPS TO REFLECT RADAR.
LLVL JET STRENGTHENING UPSTREAM AHEAD OF UPPER TROUGH AND AS THIS
MOVES EAST IT WILL SUPPORT INCREASINGLY WIDESPREAD SHOWERS.

EVENING UPDATE...NO MAJOR CHANGES ARE NEEDED TO THE GOING FCST
OVERNIGHT. THE HI-RES MODELS HAVE HANDLED THE LULL IN PRECIP AS THE
H5 S/W ENERGY HAS BEEN MUTED TRAVERSING THE RIDGE AXIS. STILL LOOKS
GOOD FOR THE WARM FRONT ADVANCING TOWARD THE AREA DURING THE DAY
TOMORROW AND LLVL MOISTURE BEING MAINTAINED WHILE ISEN LIFT
INCREASES OVERNIGHT. THIS WILL SPAWN OFF MORE -SHRA ACROSS THE SRN
ZONES TO GO ALONG WITH THE WAVES OF ENERGY CROSSING THE NRN PART OF
THE CWFA. SO...NO CHANGES TO THE CAT POPS WILL BE MADE WITH THIS
UPDATE. DON/T ANTICIPATE ANY GOOD CHANCE THUNDER AS THE LLVL WEDGE
WILL REMAIN IN PLACE AND OVERALL BROAD SCALE SUBSIDENCE WILL HOLD
VERTICAL CELL DEVELOPMENT IN CHECK AS IS SEEN WITH THE FEW SHOWERS
ADVANCING FROM THE SW ATTM.

730 PM EDT UPDATE...THE PRECIP SHIELD IS STILL BEING WELL MAINTAINED
BY CHANNELED UPPER ENERGY AND ATL/GOM MOISTURE FLUX. THE 88D IS
SHOWING SHALLOW CELLS EMBEDDED WITHIN THE BAND AND NO REAL GOOD
CHANCE OF THUNDER WITH WARM MID LEVELS UNDERNEATH THE RIDGE. POPS
WERE ADJ UP ACROSS THE NRN ZONES WHERE THE BANDING HAS SET UP. A
DECREASE IN PRECIP COVERAGE WAS ADDED IN THE GRIDS OVER THE NEXT 3
HRS BASED ON THE HRRR AND HI/RES WRF INDICATING A N/LY LIFT AND SOME
LOSS OF ULVL SUPPORT. TEMPS WERE REDUCED A LITTLE TO ACCOUNT FOR THE
AREAS COOLER THAN FCST/D DUE TO LIGHT TO CONTINUED MODERATE PRECIP.

430 PM EDT UPDATE...BUMPED UP POPS ACROSS THE LOWER NC PIEDMONT AND
UPSTATE TO ACCOUNT FOR REGION OF LIGHT TO MODERATE RAIN ASSOCIATED
WITH TRAVERSING UPPER S/W. THE MELTING LAYER IS AROUND 6.5 KFT...SO
A BRIGHT BANDING IS INDICATED ON THE DUAL POL IN RELATION TO GRAUPEL
AND MELTING SNOW. DONT ANTICIPATE VERY TALL OR LONG LIVED CELLS IN
THIS ENVIRONMENT. HOURLY TEMPS HAVE BEEN ADJ DOWN A COUPLE DEGREES
MAINLY ACROSS THE UPSTATE AS THE THICK MULTI/LAYERED CLOUDS AND
PRECIP DRAG HAS KEPT THINGS COOLER THAN FCST/D.

AS OF 230 PM...SFC LOW PRESSURE WAS ANALYZED OVER THE ARKLATX AS
HIGH PRESSURE REMAINED CENTERED OVER THE NEW ENGLAND COAST. LATEST
WV IMAGES INDICATED THAT A MID LEVEL S/W WAS RIPPLING ALONG THE
KY/TN LINE. REGIONAL RADAR SHOWS A WIDE BAND OF SHOWERS AHEAD OF THE
WAVE...WEST ALONG A WARM FRONT ASSOCIATED WITH THE LOW.
OVERNIGHT...THE SFC LOW IS FORECAST TO TRACK NE...REACHING THE
SOUTHERN OHIO RIVER VALLEY BY 12Z SUN. THE SFC PATTERN BETWEEN THE
LOW AND RIDGING HIGH PRESSURE WILL PRODUCE STRENGTHENING SE LLVL
FLOW. IN ADDITION...A RIBBON OF JET DIVERGENCE WILL REMAIN ACROSS
THE SOUTHERN APPALACHIANS OVERNIGHT. THE COMBINATION OF DEEP
MOISTURE...UPSLOPE FLOW...AND UPPER SUPPORT SHOULD SUPPORT
WIDESPREAD SHOWERS ACROSS THE MTNS TONIGHT. AREAS EAST WILL CONTINUE
TO SEE ROUNDS OF SHRA...SUPPORTED MAINLY BY INCREASING 295K
ISENTROPIC LIFT. RAINFALL OVERNIGHT MAY RANGE FROM 0.75 TO AN
INCH...WITH PIEDMONT QPF RANGING FROM .3 TO .4 TO LESS ACROSS THE
ACROSS THE LAKELANDS. LOW TEMPERATURES WILL RANGE FROM THE U40S
ACROSS THE MTNS TO L50S EAST.

SUNDAY...LLVL ISENTROPIC LIFT WILL SUPPORT WIDESPREAD COVERAGE
THROUGH THE DAY. RAINFALL RATES MAY INCREASE DURING THE AFTERNOON AS
THE MID LEVEL TROF APPROACHES. IN ADDITION...NAM CAPES POOL ACROSS
THE NE GA...UPSTATE...AND SOUTHERN NC PIEDMONT TO 300-600 J/KG. DUE
TO THE INSTABILITY AND FORCING...I WILL INCREASE THE MENTION OF
TSRA. OVERALL...POPS WILL PEAK AROUND 100 PERCENT AT SOME POINT
DURING THE DAY. QPF ON SUNDAY RANGES A LITTLE OVER AN INCH ACROSS
THE SOUTHERN ESCARPMENT TO NEAR 0.75 EAST. HIGH TEMPERATURES WILL
FEATURE A CAD PATTERN WITH U50S ACROSS THE MTNS AND MID TO UP 60S
EAST.

&&

.SHORT TERM /TONIGHT THROUGH TUESDAY NIGHT/...
AS OF 240 PM SAT...THE MAIN FORCING FROM THE LIFTING TROUGH AXIS
WILL MOVE THROUGH THE FORECAST AREA SUNDAY NIGHT IN THE FORM OF DEEP
LAYER DPVA...UPPER DIVERGENCE IN THE ENTRANCE REGION OF THE JETLET
STRETCHED UP THE APPALACHIANS...AND CONTINUED MOIST UPGLIDE IN S/SW
850 MB FLOW. THERE APPEARS TO BE SOME TREND TOWARD THE BEST FOCUS OF
OVERNIGHT QPF INTO THE PIEDMONT AND AWAY FROM THE MTNS. THIS MAKES
PINNING DOWN THE HYDRO THREAT AREA WITH ENOUGH CERTAINTY FOR A WATCH
MORE PROBLEMATIC AS THE 2.5 TO 3 INCH RAINFALL SWATH MAY NOW COVER A
GOOD CHUNK OF THE AREA. WILL CONTINUE TO FEATURE THE HEAVY RAIN
THREAT IN THE HWO AND NOW HIGHLIGHT ALL AREAS...INCLUDING CHARLOTTE
METRO.

THE AXIS OF THE UPPER TROUGH WILL CROSS THE REGION ON MONDAY...WITH
GRADUAL MID LEVEL DRYING BEHIND THE FEATURE. GIVEN THE ABUNDANT
LINGERING LOW LEVEL MOISTURE AND SLIGHTLY STEEPENING LAPSE RATES
UNDER THE PASSING TROUGH...THERE SHOULD BE ENOUGH INSTABILITY FOR
DECENT SCATTERED THUNDERSTORM COVERAGE THROUGH THE AFTN
HOURS...ESPECIALLY IN PIEDMONT SECTIONS.

UPPER RIDGING WILL DEVELOP MONDAY NIGHT THROUGH TUE NIGHT...BUT WITH
AN H5 WEAKNESS OVER THE LOWER MS RIVER VALLEY. LOW LEVEL MOISTURE
WILL PERSIST...WITH LOW CLOUDS AND FOG POSSIBLY REDEVELOPING BY
DAYBREAK TUE. HOWEVER...PROFILES APPEAR MUCH MORE CAPPED TO DEEP
CONVECTION BY TUE WITH LITTLE TO NO TRIGGERING UNDER THE SHALLOW
RIDGE. LOW LEVEL EASTERLY FLOW WILL GET REESTABLISHED LATE TUE
THROUGH TUE NIGHT. TEMPS WILL GRADUALLY WARM THROUGH THE PERIOD.

&&

.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
AS OF 220 PM SATURDAY...THE MEDIUM RANGE REMAINS UNSETTLED...AS
PERSISTENT SOUTH TO SE FLOW MAINTAINS A FETCH OF LOW LEVEL MOISTURE
INTO THE REGION...SUPPORTING MAINLY DIURNAL CHANCES FOR SHOWERS AND
THUNDERSTORMS. INSTABILITY WILL BE BEST IN THIS PERIOD WEDNESDAY
AFTERNOON WITH CAPES ON THE OLD ECMWF 300 TO 500 BUT VERY LOW ON THE
MOST RECENT GFS. THAT IS THE DEPICTION ON THE GFS MODEL. THE ECMWF
IS SHOWING MUCH DRIER WEATHER FOR OUR IMMEDIATE REGION NEXT WEEKEND
AS IT HAS THE CLOSED OFF 500MB LOW OVER EASTERN KANSAS. THIS MODEL
SEEMS TO NOT BE AS RELIABLE GOING INTO THE SPRING. THE GFS ON THE
OTHER HAND HAS THE DEEP UPPER LOW OVER ARKANSAS FRIDAY AND ARRIVING
OVER HUNTSVILLE AL SUNDAY MORNING. IF THE GFS VERIFIES...DIURNAL
CONVECTION WEDNESDAY AND THURSDAY...INCREASING IN COVERAGE FRIDAY
AND SATURDAY AS A SURFACE LOW DEVELOPS LATE THURSDAY OVER LA AND
PULLS A WARM FRONT FROM AL TO THE CAROLINAS FRI AND SAT. AS THE WARM
FRONT PASSES ON SATURDAY...THE LOW LEVEL WIND FLOW WILL SWITCH
AROUND FROM EASTERLY TO WEST.  THE AREA NEAR THE WARM FRONT LOOKS TO
BE A GOOD ZONE OF LOW LEVEL CONVERGENCE AND THE 6 HOUR PRECIP ON THE
GFS INDICATES NEAR A THIRD TO A HALF INCH. AFTER SAYING
THIS...CONFIDENCE IN THE EVENTUAL OUTCOME A WEEK FROM NOW IS LOW AND
PREFER TO BE CONSERVATIVE WITH THE POP FORECAST KEEPING IT LOW IN
THE SLIGHT TO LOW CHANCE. TEMPERATURES WILL BE BELOW NORMAL FOR
HIGHS AND ABOVE NORMAL FOR LOWS EARLY IN PERIOD THEN DROPPING BELOW
NORMAL NEXT WEEKEND AS THE UPPER LOW COMES OVER OUR REGION.

&&

.AVIATION /06Z SUNDAY THROUGH THURSDAY/...
AT KCLT...COLD WEDGE IN CONTROL INITIALLY FOR THE PERIOD...
MAINTAINING EASTERLY WINDS. VFR CIGS WILL LOWER OVER THE NEXT FEW
HRS AS UPPER FORCING CROSSES AND ENHANCES LIFT FROM WARM ADVECTION
OVER THE WEDGE...WITH SHOWERS ALSO INCREASING IN COVERAGE TOWARD
DAWN. GUIDANCE PRETTY SOLID WITH CIGS DROPPING TO MVFR AND REMAINING
THERE THRU MORNING. STILL BETTER FORCING ARRIVES BY AFTERNOON...WITH
THE WEDGE BEGINNING TO BREAK DOWN AND ALLOWING SOME BETTER
INSTABILITY TO WORK IN. HENCE PROB30 TSRA WITH IFR VSBY FOR THE
AFTERNOON. DESPITE THE POSSIBLE EROSION OF THE WEDGE...STILL
PLENTIFUL LLVL MOISTURE WILL ALLOW IFR CIGS TONIGHT.

ELSEWHERE...AHEAD OF PROMINENT UPPER SHORTWAVE TROUGH MIDLEVEL WINDS
WILL RAMP UP THRU THE FIRST FEW HOURS OF THE TAF PERIOD. INCREASING
SHOWER ACTIVITY WILL INITIALLY BE SEEN IN THE WESTERN HALF OF THE
FCST AREA BEFORE SPREADING EAST BY DAYBREAK. PRECIP GENERALLY
EXPECTED TO DROP VSBY TO MVFR BUT WITH THE ENHANCED LIFT CIGS WILL
BE ABLE TO DROP TO IFR ACROSS PORTIONS OF THE AREA AROUND 12Z. SOME
IMPROVEMENT MAY BE SEEN DURING THE DAY AS THE COLD WEDGE OVER THE
REGION BEGINS TO ERODE LIMITING THE LLVL FORCING FOR CLOUDS/PRECIP.
HOWEVER RESTRICTIONS OF AT LEAST MVFR ARE LIKELY TO CONTINUE THRU
THE PERIOD WITH LLVL MSTR PROFILES STAYING SATURATED. CURRENTLY
EXPECT MANY SITES TO HIT IFR THRESHOLD AFTER 00Z MON.

OUTLOOK...AN UPPER LEVEL WAVE WILL CROSS THE REGION ON
MONDAY...ACCOMPANIED BY SCATTERED THUNDERSTORMS AND ASSOCIATED
RESTRICTIONS. LOW CLOUDS AND FOG WILL THEN BE POSSIBLE EACH MORNING
THROUGH MID WEEK.

CONFIDENCE TABLE...

            06-12Z        12-18Z        18-24Z        00-06Z
KCLT       HIGH  94%     MED   75%     HIGH  83%     HIGH  96%
KGSP       HIGH  89%     MED   62%     HIGH  82%     HIGH  97%
KAVL       HIGH  91%     HIGH  92%     HIGH  88%     HIGH  86%
KHKY       MED   74%     LOW   56%     HIGH  81%     HIGH  98%
KGMU       MED   71%     MED   62%     MED   72%     HIGH  92%
KAND       MED   73%     LOW   52%     MED   65%     HIGH  80%

THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)

WWW.WEATHER.GOV/GSP/AVIATION_TABLES

&&

.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.

&&

$$
SYNOPSIS...DEO
NEAR TERM...NED/SBK/WIMBERLEY
SHORT TERM...HG
LONG TERM...DEO
AVIATION...WIMBERLEY







WEATHER FORECAST DISCUSSION.



 GIVEN RELATIVE LACK OF MOISTURE BELOW ABOUT 600MB...THINK CHANCE OF
CONVECTION DEVELOPING ALONG THE BOUNDARY WILL INITIALLY BE QUITE LOW
AND HAVE KEPT MOST AREAS DRY UNTIL THE LATE AFTERNOON/EVENING...AS
THE BOUNDARY MOVES INTO SLIGHTLY BETTER MOISTURE NEAR/SOUTHEAST OF
HIGHWAY 60 CORRIDOR IN NORTHWEST IOWA/SOUTHWEST MINNESOTA. DO NOT
ANTICIPATE ANY SEVERE WEATHER DURING THIS TIME...ALTHOUGH WITH THE
INITIALLY DRY SUB-CLOUD LAYER WOULD NOT BE SURPRISED TO SEE SOME
WIND GUSTS IN THE 40-50MPH RANGE. THIS ACTIVITY SHOULD FOLLOW THE
FRONT SOUTHWARD THROUGH THE EVENING...WITH RAIN CHANCES INCREASING
FROM THE SOUTHWEST IN THE LATE EVENING/OVERNIGHT AS SHORTWAVE MOVES
EAST ALONG STRENGTHENING MID LEVEL FRONT IN OUR FAR SOUTHERN CWA.
THIS ACTIVITY SHOULD BE FAIRLY QUICK MOVING AND LIGHT...WITH THE
SHORTWAVE EXITING THE CWA TOWARD 12Z MONDAY.

.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 458 AM CDT SUN APR 28 2013

SOMEWHAT MORE UNSETTLED PATTERN DEVELOPING ACROSS THE REGION THIS
WEEK...AS GENERALLY ZONAL FLOW ALOFT TRANSITIONS TO BROAD TROUGH
OVER THE WESTERN CONUS THROUGH THE EARLY PART OF THE WEEK...AND
EVENTUALLY TO A CUTOFF UPPER LOW OVER THE CENTRAL PLAINS BY THE
LATTER PART OF THE WEEK. ONE SHORTWAVE SLIDING THROUGH THE BASE OF
THE TROUGH ALONG THE CANADIAN BORDER MONDAY NIGHT. FRONTAL BOUNDARY
WHICH PUSHES THROUGH US TODAY WILL LIFT BACK TO THE NORTH ON MONDAY
AHEAD OF THIS WAVE...THEN MOVE SOUTHEAST ACROSS THE FORECAST AREA
WITH A STRONGER PUSH OF COOLER AIR LATE MONDAY NIGHT AND TUESDAY.
MONDAY SHOULD BE ANOTHER MILD DAY...THOUGH NOT QUITE AS WARM AS THE
WEEKEND IN MOST AREAS WITH WARMEST LOW LEVEL AIR NOT SPREADING INTO
THE AREA UNTIL MONDAY LATE AFTERNOON/EVENING. STILL LOOKING AT HIGHS
IN THE UPPER 60S AND 70S THOUGH.

LOW LEVEL JET AHEAD OF THE BOUNDARY COULD TRIGGER A FEW HIGH BASED
SHOWERS OR STORMS IN OUR FAR NORTHERN CWA MONDAY NIGHT...THOUGH
BETTER CHANCE OF THIS LOOKS TO REMAIN NORTH OF THE AREA WITH BETTER
UPPER FORCING THROUGH NORTH DAKOTA/NORTHERN MINNESOTA.

COLD AFFECTION THROUGH THE DAY TUESDAY...THOUGH MIXY WITH STOUT
NORTHERLY FLOW BEHIND THE FRONT SO STILL POTENTIAL TO SEE NEAR
NORMAL HIGHS FOR THE LAST DAY OF APRIL. CURRENT THINKING ON TIMING
OF THE FRONT PUTS IT SOUTHEAST OF OUR FORECAST AREA BY MIDDAY WITH
850MB FRONT NOT FAR BEHIND. THIS SHOULD LIMIT ANY PRECIP THREAT IN
OUR AREA DURING THE DAY. RAIN CHANCES DRAMATICALLY INCREASE TUESDAY
NIGHT AND WEDNESDAY AS MAIN UPPER TROUGH BEGINS TO SWING OUT OF THE
ROCKIES. GOOD MODEL CONSENSUS PLACING A STRONG MID LEVEL FRONT OVER
THE SOUTHEAST HALF OF OUR FORECAST AREA BY 06Z WEDNESDAY...WITH THE
MID LEVEL BOUNDARY THEN JUST SLOWLY SHIFTING EASTWARD THROUGH THE
DAY WEDNESDAY. HAVE BUMPED POPS INTO HIGHER LIKELY RANGE FOR THESE
PERIODS. STRONGEST PUSH OF COLD AIR WILL FOLLOW THIS BOUNDARY INTO
THE REGION...WITH 850MB AND EVEN 925MB TEMPERATURES BELOW FREEZING
BY WEDNESDAY AFTERNOON. WITH JUST A SHALLOW NEAR-SURFACE LAYER ABOVE
FREEZING...RAIN/SNOW MIX QUITE POSSIBLE IN SOME AREAS...AND WILL
KEEP MENTION OF RAIN/SNOW MIX RIGHT THROUGH THURSDAY NIGHT AS ANY
SURFACE-BASED WARM LAYER REMAINS QUITE SHALLOW.

MODELS HAVE COME INTO SOMEWHAT BETTER AGREEMENT IN HANDLING UPPER
LOW AS IT DIGS INTO THE SOUTHERN PLAINS AND CUTS OFF FROM THURSDAY
ON. STILL SOME FINE DETAILS SHOWING DISAGREEMENT...LIKE EXACT
POSITIONING AND AMOUNT OF MOISTURE WRAPPING AROUND THE NORTH SIDE OF
THE CUTOFF INTO OUR FORECAST AREA. DEPENDING ON TIMING... COULD SEE
A DRIER PERIOD OVER MUCH OF THE AREA THURSDAY THROUGH FRIDAY...
THOUGH ENOUGH UNCERTAINTY THAT HAVE KEPT CHANCE POPS IN MAINLY THE
EASTERN HALF OF THE CWA THROUGH THIS TIME. CHANCES LOOK TO INCREASE
AGAIN SATURDAY AS BOTH ECMWF AND GFS BEGIN TO SWING THE UPPER LOW
NORTHWARD THROUGH THE CENTRAL PLAINS.

WITH RE-ENTRY INTO WELL BELOW NORMAL REGIME FOR THE LATTER HALF OF
THE WEEK...HAVE LOWERED FORECAST HIGHS FROM WEDNESDAY ON CLOSER TO
RAW MODEL OUTPUT...AS NUMERICAL GUIDANCE IS AGAIN SHOWING STRONGER
INFLUENCE FROM MUCH WARMER CLIMATOLOGY VALUES.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1241 PM CDT SUN APR 28 2013

GENERALLY VFR CONDITIONS EXPECTED THROUGH THE PERIOD. COLD FRONT
CURRENTLY PROGRESSING THROUGH THE REGION. SOUTH OR SOUTHWESTERLY
WINDS AHEAD OF IT WILL TRANSITION TO NORTH OR NORTHWEST BEHIND IT.
COULD SEE A FEW SHOWERS OR THUNDERSTORMS FORM ALONG THE COLD FRONT
THIS AFTERNOON ACROSS NORTHWEST IOWA AND SOUTHWEST MINNESOTA...BUT
CONFIDENCE IS TOO LOW TO INCLUDE IN THE TAFS. JUST SOMETHING TO WATCH
AS WE HEAD THROUGH THE AFTERNOON...AS GUSTY WINDS AND SMALL HAIL
WOULD BE POSSIBLE IF A STORM WAS ABLE TO FORM. A WAVE RIDING ALONG
THE MID LEVEL FRONT MAY BRING A FEW SHOWERS ALONG THE MISSOURI RIVER
LATER TONIGHT AS WELL. WINDS BEHIND THE FRONT LOOK TO STAY BLUSTERY
THROUGH THE NIGHT...WITH NORTHERLY GUSTS AROUND 20 TO 25 KTS
POSSIBLE.

&&

.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&

$$

UPDATE...CHENARD
SHORT TERM...JH
LONG TERM...JH
AVIATION...CHENARD







AREA FORECAST DISCUSSION

NWS FORT WORTH TX

 1252 PM CDT SUN APR 28 2013

.AVIATION...
MORNING STRATUS FINALLY BURNING OFF...AND VFR CONDITIONS ARE
EXPECTED THRU THE TAF PERIOD AT METROPLEX AIRPORTS. WACO FORECAST
SOUNDINGS SUGGEST RADIATION FOG IN THE MORNING...AND HAVE
INDICATED REDUCED VISIBILITIES NEAR SUNRISE. FOG SHOULD BURN OFF
QUICKLY WITH THE LAYER EXPECTED TO BE MUCH MORE SHALLOW THAN
TODAY. 84

&&

.UPDATE...
A PESKY BAND OF LOW CLOUDS HAVE BEEN MUCH SLOWER TO DISSIPATE
THAN WE HAD EXPECTED. THIS BAND OF CLOUDS ALONG THE I-20 CORRIDOR
FROM FORT WORTH EAST INTO LOUISIANA AND ALONG THE I-35 CORRIDOR
FROM DENTON TO JUST SOUTH OF WACO...SHOULD MIX OUT EARLY THIS
AFTERNOON. HAVE UPDATED THE CLOUD COVER AND HOURLY TEMPERATURE
FORECASTS TO ACCOUNT FOR THE CLOUDS. A WARM FRONT THAT EXTENDED
FROM NORTH OF LAMPASAS TO JUST SOUTH OF LUFKIN WILL MOVE NORTH
TODAY. LIGHT MOSTLY EAST TO SOUTHEAST WINDS TO THE NORTH OF THE
FRONT WILL BECOME SOUTHERLY AT AROUND 10 MPH AS THE FRONT MOVES
THROUGH. TEMPERATURES WILL STILL WARM INTO THE UPPER 70S TO MID
80S ACROSS THE REGION THIS AFTERNOON.

58

&&

.PREV DISCUSSION... /ISSUED 359 AM CDT SUN APR 28 2013/

REGIONAL RADAR MOSAIC SHOWS A BROAD AREA OF CONVECTION EXTENDING
FROM BRYAN SOUTHWEST ALONG THE TX GULF COAST TO CORPUS CHRISTI
EARLY THIS MORNING. 08Z /3AM/ SURFACE OBSERVATIONS SHOWED A
DIFFUSE FRONTAL BOUNDARY LOCATED JUST SOUTHEAST OF A LINE FROM
TEMPLE TO PALESTINE. THE BOUNDARY WAS MOST EVIDENT IN THERMAL AND
MOISTURE FIELDS AS LOW LEVEL WINDS HAVE ALREADY STARTED TO COME
AROUND TO THE SOUTHEAST TO THE NORTH OF THE FRONT. WATER VAPOR
SATELLITE IMAGERY SHOWED A COMPACT UPPER LOW OVER THE IN/IL BORDER
MOVING EAST-NORTHEAST EARLY THIS MORNING. WATER VAPOR IMAGERY ALSO
SHOWED A CYCLONIC SHEAR AXIS OR TROUGH TRAILING BEHIND THE UPPER
LOW TO THE SOUTHWEST. THIS TROUGH WAS LOCATED OVER THE CWA AS OF
08Z AND WAS MOVING SLOWLY SOUTHEAST. ALONG THE DIFFUSE FRONTAL
BOUNDARY...IR SATELLITE IMAGERY SHOWED MOSTLY CLOUDY SKIES WHICH
WAS HELPING TO KEEP TEMPERATURES IN THE LOWER TO MID 60S NEAR THE
FRONT. TO THE NORTHWEST OF THE FRONT THERE WAS A SHARP CUT-OFF IN
CLOUD COVER...ALLOWING TEMPERATURES TO FALL INTO THE 50S FOR MOST
OF NORTH TX EARLY THIS MORNING.

TODAY...THE UPPER LEVEL TROUGH IS EXPECTED TO SLOWLY MOVE
SOUTHEAST OF THE CWA TODAY...SPREADING WEAK LARGE SCALE FORCING
FOR SUBSIDENCE OVER THE AREA. SURFACE WINDS ARE EXPECTED TO RETURN
TO THE SOUTH TODAY WHICH MAY CAUSE THE WEAK FRONTAL BOUNDARY TO
LIFT NORTH ACROSS THE CWA THIS AFTERNOON. IT IS DIFFICULT TO
DETERMINE IF THIS WILL BE OF ANY CONSEQUENCE... BECAUSE THE RETURN
TO SOUTH WINDS UNDER MOSTLY SUNNY SKIES WILL MORE OR LESS
ELIMINATE ANY THERMAL GRADIENT/BAROCLINICITY ASSOCIATED WITH THE
FRONT.

BY DEFINITION THIS BOUNDARY WOULD NOT COUNT AS A FRONT ANYMORE
WITHOUT A DISCERNABLE THERMAL GRADIENT. HOWEVER...THERE WILL STILL
BE SOME SORT OF MOISTURE DISCONTINUITY ASSOCIATED WITH THE
BOUNDARY AS IT LIFTS NORTH TODAY...LIKELY RESULTING IN A SLIGHT
INCREASE IN RELATIVE HUMIDITY. NORMALLY THIS WOULD HAVE LITTLE
IMPACT ON THE FORECAST...BUT TODAY THE NAM AND RAP FORECAST
SOUNDINGS INDICATE THAT THE AFTERNOON INCREASE IN LOW-LEVEL
HUMIDITY IS SUFFICIENT TO RESULT IN AN ALMOST COMPLETE REMOVAL OF
THE CAP FROM THE FORECAST AREA DURING THE PEAK HEATING HRS OF THE
DAY. WITH NO CAP...IT IS POSSIBLE THAT SOME WEAK FORCING FOR
ASCENT COULD RESULT IN ISOLATED THUNDERSTORMS ACROSS NORTH TX BY
LATE THIS AFTERNOON.

AT THIS TIME...LEFT THE FORECAST DRY BECAUSE OF A LACK OF
DISCERNABLE FOCUS FOR THUNDERSTORM INITIATION THIS AFTERNOON. THE
SUBSIDENCE BEHIND THE UPPER LEVEL TROUGH IS EXPECTED TO BE
WEAK...BUT IN THE ABSENCE OF STRONG MESOSCALE FORCING FOR
ASCENT...THIS SHOULD BE SUFFICIENT TO KEEP US DRY DESPITE A NEARLY
UNCAPPED AFTERNOON THERMODYNAMIC ENVIRONMENT. OTHERWISE...WITH
MOSTLY SUNNY SKIES AND A RETURN TO SOUTH WINDS TODAY EXPECT
TEMPERATURES TO CLIMB INTO THE 80S FOR MOST LOCATIONS DESPITE THE
COOL START TO THE DAY THIS MORNING.

MONDAY AND TUESDAY...THE ECMWF/GFS/CANADIAN NOW ALL SHOW THE THAT
THE WESTERN EDGE OF OUR SOUTHEASTWARD MOVING TROUGH TODAY EVOLVES
INTO AN UPPER LEVEL CLOSED LOW OVER THE TX GULF COAST MONDAY INTO
TUESDAY. THIS WEAK UPPER LOW WILL LIKELY CAUSE CLUSTERS OF STORMS
TO DEVELOP EACH DAY ACROSS FAR SOUTH TX OR ALONG THE TX GULF
COAST...LIKELY WORKING TO REINFORCE THE UPPER LEVEL CIRCULATION
THROUGH THE PERIOD. DUE TO THE FORECAST POSITION OF THE UPPER LOW
TO OUR SOUTH...THIS FEATURE SHOULD ONLY REINFORCE UPPER LEVEL
SUBSIDENCE OVER THE CWA HELPING TO KEEP US DRY FOR EARLY THIS
WEEK. PERSISTENT SOUTHERLY FLOW WILL CONTINUE CAUSING SHALLOW GULF
MOISTURE TO REMAIN IN PLACE OVER THE CWA...BUT THUNDERSTORM
CHANCES SHOULD BE VERY LOW AS LONG AS THE UPPER LOW OVER THE GULF
COAST EVOLVES AS EXPECTED. AT ANY RATE...MOSTLY SUNNY SKIES AND
PERSISTENT SOUTHERLY FLOW WILL KEEP US ABOVE NORMAL FOR
TEMPERATURES WITH HIGHS IN THE MID TO UPPER 80S EACH DAY.

WEDNESDAY THROUGH FRIDAY...A POWERFUL UPPER LOW FROM THE GULF OF
ALASKA IS STILL EXPECTED TO MOVE SOUTHEAST OVER THE PLAINS
WEDNESDAY NIGHT INTO THURSDAY. THIS WILL SEND AN UNSEASONABLY
STRONG COLD FRONT SOUTH THROUGH THE PLAINS AND ACROSS NORTH TEXAS
LIKELY WEDNESDAY EVENING AND OVERNIGHT. AS LONG AS THE UPPER LOW
DIGS AS FAR SOUTH AS THE RED RIVER...WHICH IS ADVERTISED BY THE
OPERATIONAL ECMWF/GFS/CANADIAN...THERE SHOULD BE A NEARLY SOLID
LINE OF SHOWERS AND THUNDERSTORMS ACCOMPANYING THE FRONT. THE FRONT
IS EXPECTED TO MOVE THROUGH THE AREA VERY FAST...SO OVERALL
RAINFALL AMOUNTS WILL LIKELY BE SMALL...BUT MOST LOCATIONS SHOULD
AT LEAST SEE SOME LIGHT RAIN AS THE FRONT MOVES THROUGH THE AREA.
BUMPED UP POPS INTO THE 40 TO 50 PERCENT RANGE ALONG AND BEHIND
THE FRONT AS A RESULT. DID NOT GO HIGHER AT THIS TIME BECAUSE OF
UNCERTAINTY REGARDING THE TIMING OF THE FRONT. WHILE OPERATIONAL
MODELS ARE CONSISTENT WITH THE FRONTAL PASSAGE RIGHT NOW...THE
FRONT IS STILL AT LEAST 84 HRS OUT...AND OUR MEDIUM RANGE GUIDANCE
IS NOTORIOUSLY BAD AT PREDICTING THE TIMING OF STRONG COLD FRONTS.
THEREFORE WILL CONTINUE TO REFINE POPS AND THE TIMING OF THE FRONT
IN FUTURE FORECASTS.

SEVERE WEATHER CHANCES OUT AHEAD OR ALONG THE FRONT DO NOT LOOK
GREAT PRIMARILY BECAUSE OF THE PROGGED FAST MOTION OF THE FRONT
THROUGH THE PLAINS. SOME SEVERE WEATHER MAY BE ADDED TO THE
FORECAST AS THE FRONT GETS CLOSER...BUT FOR NOW THE OVERALL
PATTERN DOES NOT SEEM TO SUPPORT A REGIONAL OUTBREAK OF SEVERE
STORMS...SO WILL NOT HIGHLIGHT ANY SEVERE WEATHER IN PRODUCTS AT
THIS TIME. TEMPERATURES BEHIND THE FRONT ARE EXPECTED TO BE VERY
COLD FOR EARLY MAY...WITH RECORD LOW TEMPERATURES LIKELY BEHIND
THE FRONT THURSDAY NIGHT. RECORD LOWS THURSDAY NIGHT WILL HELP
KEEP TEMPERATURES COOL HEADED INTO THE WEEKEND.

THIS WEEKEND...THE ECMWF IS LESS BULLISH WITH ITS FORECAST OF A
BLOCKING PATTERN THAT WOULD KEEP THE UPPER LOW ANCHORED IN THE
CENTRAL PLAINS FOR SEVERAL DAYS. THE NAEFS IS ALSO LEANING MORE
TOWARDS THE UPPER LOW MOVING NORTHEAST OUT OF THE REGION BY EARLY
NEXT WEEK. THAT SAID...THE NAEFS MEAN AND THE LAST EVENING RUN OF
THE ECMWF BOTH KEEP GENERAL TROUGHINESS OVER THE CENTRAL
CONUS...MEANING TEMPERATURES WILL LIKELY BE NEAR OR MAYBE SLIGHTLY
BELOW SEASONAL NORMALS. AFTER NEAR RECORD OR RECORD LOWS THURSDAY
NIGHT/FRIDAY MORNING...THERE IS LITTLE PLACE FOR THE TEMPERATURES
TO GO BUT UP. TEMPERATURES WILL MODERATE BACK TOWARDS SEASONAL
NORMALS THIS WEEKEND INTO EARLY NEXT WEEK...AND NOT JUST BECAUSE
MOS GUIDANCE TRENDS TOWARDS CLIMATOLOGY OUT ON DAY 7. THICKNESS
AND HEIGHT RISES WILL HELP USHER IN WARMER TEMPERATURES AS LONG AS
THE UPPER LOW DOES MOVE NORTHEAST OF THE PLAINS BY EARLY NEXT
WEEK. THE EXTENDED FORECAST IS DRY FOR NOW...HOWEVER WITH GENERAL
CYCLONIC FLOW IN PLACE THERE WILL UNDOUBTEDLY BE SOME SMALL
FEATURES THAT NECESSITATE THE INCLUSION OF PRECIPITATION DURING
THIS PERIOD IN FUTURE FORECASTS. AT THIS TIME THERE IS JUST NOT
ENOUGH CONSISTENCY TO PLACE POPS IN ONE PERIOD OVER ANOTHER...SO
LEFT THE FORECAST DRY WITH 10 POPS IN PLACE FOR SEVERAL DAYS.

CAVANAUGH



&&


.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX  84  61  86  63  87 /  10   0   0   0   5
WACO, TX              84  58  84  60  86 /  10   0   0   0   5
PARIS, TX             79  55  83  58  84 /  10   0   0   0   5
DENTON, TX            83  58  87  59  87 /  10   0   0   0   5
MCKINNEY, TX          82  58  84  60  86 /  10   0   0   0   5
DALLAS, TX            83  62  86  64  87 /  10   0   0   0   5
TERRELL, TX           82  57  83  59  84 /  10   0   0   0   5
CORSICANA, TX         82  58  83  59  84 /  10   0   0   0  10
TEMPLE, TX            83  57  83  59  85 /  10   5   0   0   5
MINERAL WELLS, TX     83  58  86  59  87 /  10   0   0   0   5

&&

.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.

&&

$$






AREA FORECAST DISCUSSION

NWS FORT WORTH TX

 1024 AM CDT SUN APR 28 2013

.UPDATE...
A PESKY BAND OF LOW CLOUDS HAVE BEEN MUCH SLOWER TO DISSIPATE
THAN WE HAD EXPECTED. THIS BAND OF CLOUDS ALONG THE I-20 CORRIDOR
FROM FORT WORTH EAST INTO LOUISIANA AND ALONG THE I-35 CORRIDOR
FROM DENTON TO JUST SOUTH OF WACO...SHOULD MIX OUT EARLY THIS
AFTERNOON. HAVE UPDATED THE CLOUD COVER AND HOURLY TEMPERATURE
FORECASTS TO ACCOUNT FOR THE CLOUDS. A WARM FRONT THAT EXTENDED
FROM NORTH OF LAMPASAS TO JUST SOUTH OF LUFKIN WILL MOVE NORTH
TODAY. LIGHT MOSTLY EAST TO SOUTHEAST WINDS TO THE NORTH OF THE
FRONT WILL BECOME SOUTHERLY AT AROUND 10 MPH AS THE FRONT MOVES
THROUGH. TEMPERATURES WILL STILL WARM INTO THE UPPER 70S TO MID
80S ACROSS THE REGION THIS AFTERNOON.

58

&&

.AVIATION...
MVFR VISIBILITY RESTRICTIONS ARE LIKELY TO CONTINUE AT WACO
THROUGH 14 OR 15Z. BR IS PRESENT AROUND THE METROPLEX...BUT URBAN
HEAT ISLAND IS KEEPING TEMPERATURES HIGHER AND CONDITIONS CLEAR.
CANT RULE OUT BRIEF RESTRICTIONS JUST AFTER DAYBREAK...BUT
PROBABILITIES WERE TOO LOW TO MENTION IN THE TAF. PROBABILITIES
WOULD BE GREATEST AT KGKY...KFTW AND KAFW. OTHERWISE...WINDS WILL
BECOME SOUTHERLY TODAY...AND SKIES WILL REMAIN MOSTLY CLEAR. THERE
HAVE BEEN A FEW PATCHES OF MVFR CLOUDS AROUND THE AREA
OVERNIGHT...BUT COVERAGE ISNT HIGH ENOUGH TO WARRANT A MENTION IN
THE TAFS. COULD SEE A REPEAT OF BR FOR WACO TOMORROW MORNING...BUT
WIND SPEEDS WILL BE HIGHER...WHICH WILL LIMIT THE FOG POTENTIAL.

HAMPSHIRE


&&



.PREV DISCUSSION... /ISSUED 359 AM CDT SUN APR 28 2013/

REGIONAL RADAR MOSAIC SHOWS A BROAD AREA OF CONVECTION EXTENDING
FROM BRYAN SOUTHWEST ALONG THE TX GULF COAST TO CORPUS CHRISTI
EARLY THIS MORNING. 08Z /3AM/ SURFACE OBSERVATIONS SHOWED A
DIFFUSE FRONTAL BOUNDARY LOCATED JUST SOUTHEAST OF A LINE FROM
TEMPLE TO PALESTINE. THE BOUNDARY WAS MOST EVIDENT IN THERMAL AND
MOISTURE FIELDS AS LOW LEVEL WINDS HAVE ALREADY STARTED TO COME
AROUND TO THE SOUTHEAST TO THE NORTH OF THE FRONT. WATER VAPOR
SATELLITE IMAGERY SHOWED A COMPACT UPPER LOW OVER THE IN/IL BORDER
MOVING EAST-NORTHEAST EARLY THIS MORNING. WATER VAPOR IMAGERY ALSO
SHOWED A CYCLONIC SHEAR AXIS OR TROUGH TRAILING BEHIND THE UPPER
LOW TO THE SOUTHWEST. THIS TROUGH WAS LOCATED OVER THE CWA AS OF
08Z AND WAS MOVING SLOWLY SOUTHEAST. ALONG THE DIFFUSE FRONTAL
BOUNDARY...IR SATELLITE IMAGERY SHOWED MOSTLY CLOUDY SKIES WHICH
WAS HELPING TO KEEP TEMPERATURES IN THE LOWER TO MID 60S NEAR THE
FRONT. TO THE NORTHWEST OF THE FRONT THERE WAS A SHARP CUT-OFF IN
CLOUD COVER...ALLOWING TEMPERATURES TO FALL INTO THE 50S FOR MOST
OF NORTH TX EARLY THIS MORNING.

TODAY...THE UPPER LEVEL TROUGH IS EXPECTED TO SLOWLY MOVE
SOUTHEAST OF THE CWA TODAY...SPREADING WEAK LARGE SCALE FORCING
FOR SUBSIDENCE OVER THE AREA. SURFACE WINDS ARE EXPECTED TO RETURN
TO THE SOUTH TODAY WHICH MAY CAUSE THE WEAK FRONTAL BOUNDARY TO
LIFT NORTH ACROSS THE CWA THIS AFTERNOON. IT IS DIFFICULT TO
DETERMINE IF THIS WILL BE OF ANY CONSEQUENCE... BECAUSE THE RETURN
TO SOUTH WINDS UNDER MOSTLY SUNNY SKIES WILL MORE OR LESS
ELIMINATE ANY THERMAL GRADIENT/BAROCLINICITY ASSOCIATED WITH THE
FRONT.

BY DEFINITION THIS BOUNDARY WOULD NOT COUNT AS A FRONT ANYMORE
WITHOUT A DISCERNABLE THERMAL GRADIENT. HOWEVER...THERE WILL STILL
BE SOME SORT OF MOISTURE DISCONTINUITY ASSOCIATED WITH THE
BOUNDARY AS IT LIFTS NORTH TODAY...LIKELY RESULTING IN A SLIGHT
INCREASE IN RELATIVE HUMIDITY. NORMALLY THIS WOULD HAVE LITTLE
IMPACT ON THE FORECAST...BUT TODAY THE NAM AND RAP FORECAST
SOUNDINGS INDICATE THAT THE AFTERNOON INCREASE IN LOW-LEVEL
HUMIDITY IS SUFFICIENT TO RESULT IN AN ALMOST COMPLETE REMOVAL OF
THE CAP FROM THE FORECAST AREA DURING THE PEAK HEATING HRS OF THE
DAY. WITH NO CAP...IT IS POSSIBLE THAT SOME WEAK FORCING FOR
ASCENT COULD RESULT IN ISOLATED THUNDERSTORMS ACROSS NORTH TX BY
LATE THIS AFTERNOON.

AT THIS TIME...LEFT THE FORECAST DRY BECAUSE OF A LACK OF
DISCERNABLE FOCUS FOR THUNDERSTORM INITIATION THIS AFTERNOON. THE
SUBSIDENCE BEHIND THE UPPER LEVEL TROUGH IS EXPECTED TO BE
WEAK...BUT IN THE ABSENCE OF STRONG MESOSCALE FORCING FOR
ASCENT...THIS SHOULD BE SUFFICIENT TO KEEP US DRY DESPITE A NEARLY
UNCAPPED AFTERNOON THERMODYNAMIC ENVIRONMENT. OTHERWISE...WITH
MOSTLY SUNNY SKIES AND A RETURN TO SOUTH WINDS TODAY EXPECT
TEMPERATURES TO CLIMB INTO THE 80S FOR MOST LOCATIONS DESPITE THE
COOL START TO THE DAY THIS MORNING.

MONDAY AND TUESDAY...THE ECMWF/GFS/CANADIAN NOW ALL SHOW THE THAT
THE WESTERN EDGE OF OUR SOUTHEASTWARD MOVING TROUGH TODAY EVOLVES
INTO AN UPPER LEVEL CLOSED LOW OVER THE TX GULF COAST MONDAY INTO
TUESDAY. THIS WEAK UPPER LOW WILL LIKELY CAUSE CLUSTERS OF STORMS
TO DEVELOP EACH DAY ACROSS FAR SOUTH TX OR ALONG THE TX GULF
COAST...LIKELY WORKING TO REINFORCE THE UPPER LEVEL CIRCULATION
THROUGH THE PERIOD. DUE TO THE FORECAST POSITION OF THE UPPER LOW
TO OUR SOUTH...THIS FEATURE SHOULD ONLY REINFORCE UPPER LEVEL
SUBSIDENCE OVER THE CWA HELPING TO KEEP US DRY FOR EARLY THIS
WEEK. PERSISTENT SOUTHERLY FLOW WILL CONTINUE CAUSING SHALLOW GULF
MOISTURE TO REMAIN IN PLACE OVER THE CWA...BUT THUNDERSTORM
CHANCES SHOULD BE VERY LOW AS LONG AS THE UPPER LOW OVER THE GULF
COAST EVOLVES AS EXPECTED. AT ANY RATE...MOSTLY SUNNY SKIES AND
PERSISTENT SOUTHERLY FLOW WILL KEEP US ABOVE NORMAL FOR
TEMPERATURES WITH HIGHS IN THE MID TO UPPER 80S EACH DAY.

WEDNESDAY THROUGH FRIDAY...A POWERFUL UPPER LOW FROM THE GULF OF
ALASKA IS STILL EXPECTED TO MOVE SOUTHEAST OVER THE PLAINS
WEDNESDAY NIGHT INTO THURSDAY. THIS WILL SEND AN UNSEASONABLY
STRONG COLD FRONT SOUTH THROUGH THE PLAINS AND ACROSS NORTH TEXAS
LIKELY WEDNESDAY EVENING AND OVERNIGHT. AS LONG AS THE UPPER LOW
DIGS AS FAR SOUTH AS THE RED RIVER...WHICH IS ADVERTISED BY THE
OPERATIONAL ECMWF/GFS/CANADIAN...THERE SHOULD BE A NEARLY SOLID
LINE OF SHOWERS AND THUNDERSTORMS ACCOMPANYING THE FRONT. THE FRONT
IS EXPECTED TO MOVE THROUGH THE AREA VERY FAST...SO OVERALL
RAINFALL AMOUNTS WILL LIKELY BE SMALL...BUT MOST LOCATIONS SHOULD
AT LEAST SEE SOME LIGHT RAIN AS THE FRONT MOVES THROUGH THE AREA.
BUMPED UP POPS INTO THE 40 TO 50 PERCENT RANGE ALONG AND BEHIND
THE FRONT AS A RESULT. DID NOT GO HIGHER AT THIS TIME BECAUSE OF
UNCERTAINTY REGARDING THE TIMING OF THE FRONT. WHILE OPERATIONAL
MODELS ARE CONSISTENT WITH THE FRONTAL PASSAGE RIGHT NOW...THE
FRONT IS STILL AT LEAST 84 HRS OUT...AND OUR MEDIUM RANGE GUIDANCE
IS NOTORIOUSLY BAD AT PREDICTING THE TIMING OF STRONG COLD FRONTS.
THEREFORE WILL CONTINUE TO REFINE POPS AND THE TIMING OF THE FRONT
IN FUTURE FORECASTS.

SEVERE WEATHER CHANCES OUT AHEAD OR ALONG THE FRONT DO NOT LOOK
GREAT PRIMARILY BECAUSE OF THE PROGGED FAST MOTION OF THE FRONT
THROUGH THE PLAINS. SOME SEVERE WEATHER MAY BE ADDED TO THE
FORECAST AS THE FRONT GETS CLOSER...BUT FOR NOW THE OVERALL
PATTERN DOES NOT SEEM TO SUPPORT A REGIONAL OUTBREAK OF SEVERE
STORMS...SO WILL NOT HIGHLIGHT ANY SEVERE WEATHER IN PRODUCTS AT
THIS TIME. TEMPERATURES BEHIND THE FRONT ARE EXPECTED TO BE VERY
COLD FOR EARLY MAY...WITH RECORD LOW TEMPERATURES LIKELY BEHIND
THE FRONT THURSDAY NIGHT. RECORD LOWS THURSDAY NIGHT WILL HELP
KEEP TEMPERATURES COOL HEADED INTO THE WEEKEND.

THIS WEEKEND...THE ECMWF IS LESS BULLISH WITH ITS FORECAST OF A
BLOCKING PATTERN THAT WOULD KEEP THE UPPER LOW ANCHORED IN THE
CENTRAL PLAINS FOR SEVERAL DAYS. THE NAEFS IS ALSO LEANING MORE
TOWARDS THE UPPER LOW MOVING NORTHEAST OUT OF THE REGION BY EARLY
NEXT WEEK. THAT SAID...THE NAEFS MEAN AND THE LAST EVENING RUN OF
THE ECMWF BOTH KEEP GENERAL TROUGHINESS OVER THE CENTRAL
CONUS...MEANING TEMPERATURES WILL LIKELY BE NEAR OR MAYBE SLIGHTLY
BELOW SEASONAL NORMALS. AFTER NEAR RECORD OR RECORD LOWS THURSDAY
NIGHT/FRIDAY MORNING...THERE IS LITTLE PLACE FOR THE TEMPERATURES
TO GO BUT UP. TEMPERATURES WILL MODERATE BACK TOWARDS SEASONAL
NORMALS THIS WEEKEND INTO EARLY NEXT WEEK...AND NOT JUST BECAUSE
MOS GUIDANCE TRENDS TOWARDS CLIMATOLOGY OUT ON DAY 7. THICKNESS
AND HEIGHT RISES WILL HELP USHER IN WARMER TEMPERATURES AS LONG AS
THE UPPER LOW DOES MOVE NORTHEAST OF THE PLAINS BY EARLY NEXT
WEEK. THE EXTENDED FORECAST IS DRY FOR NOW...HOWEVER WITH GENERAL
CYCLONIC FLOW IN PLACE THERE WILL UNDOUBTEDLY BE SOME SMALL
FEATURES THAT NECESSITATE THE INCLUSION OF PRECIPITATION DURING
THIS PERIOD IN FUTURE FORECASTS. AT THIS TIME THERE IS JUST NOT
ENOUGH CONSISTENCY TO PLACE POPS IN ONE PERIOD OVER ANOTHER...SO
LEFT THE FORECAST DRY WITH 10 POPS IN PLACE FOR SEVERAL DAYS.

CAVANAUGH



&&


.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX  84  61  86  63  87 /  10   0   0   0   5
WACO, TX              84  58  84  60  86 /  10   0   0   0   5
PARIS, TX             79  55  83  58  84 /  10   0   0   0   5
DENTON, TX            83  58  87  59  87 /  10   0   0   0   5
MCKINNEY, TX          82  58  84  60  86 /  10   0   0   0   5
DALLAS, TX            83  62  86  64  87 /  10   0   0   0   5
TERRELL, TX           82  57  83  59  84 /  10   0   0   0   5
CORSICANA, TX         82  58  83  59  84 /  10   0   0   0  10
TEMPLE, TX            83  57  83  59  85 /  10   5   0   0   5
MINERAL WELLS, TX     83  58  86  59  87 /  10   0   0   0   5

&&

.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.

&&

$$

84/58











AREA FORECAST DISCUSSION

NWS FORT WORTH TX

 359 AM CDT SUN APR 28 2013

.DISCUSSION...

REGIONAL RADAR MOSAIC SHOWS A BROAD AREA OF CONVECTION EXTENDING
FROM BRYAN SOUTHWEST ALONG THE TX GULF COAST TO CORPUS CHRISTI
EARLY THIS MORNING. 08Z /3AM/ SURFACE OBSERVATIONS SHOWED A
DIFFUSE FRONTAL BOUNDARY LOCATED JUST SOUTHEAST OF A LINE FROM
TEMPLE TO PALESTINE. THE BOUNDARY WAS MOST EVIDENT IN THERMAL AND
MOISTURE FIELDS AS LOW LEVEL WINDS HAVE ALREADY STARTED TO COME
AROUND TO THE SOUTHEAST TO THE NORTH OF THE FRONT. WATER VAPOR
SATELLITE IMAGERY SHOWED A COMPACT UPPER LOW OVER THE IN/IL BORDER
MOVING EAST-NORTHEAST EARLY THIS MORNING. WATER VAPOR IMAGERY ALSO
SHOWED A CYCLONIC SHEAR AXIS OR TROUGH TRAILING BEHIND THE UPPER
LOW TO THE SOUTHWEST. THIS TROUGH WAS LOCATED OVER THE CWA AS OF
08Z AND WAS MOVING SLOWLY SOUTHEAST. ALONG THE DIFFUSE FRONTAL
BOUNDARY...IR SATELLITE IMAGERY SHOWED MOSTLY CLOUDY SKIES WHICH
WAS HELPING TO KEEP TEMPERATURES IN THE LOWER TO MID 60S NEAR THE
FRONT. TO THE NORTHWEST OF THE FRONT THERE WAS A SHARP CUT-OFF IN
CLOUD COVER...ALLOWING TEMPERATURES TO FALL INTO THE 50S FOR MOST
OF NORTH TX EARLY THIS MORNING.

TODAY...THE UPPER LEVEL TROUGH IS EXPECTED TO SLOWLY MOVE
SOUTHEAST OF THE CWA TODAY...SPREADING WEAK LARGE SCALE FORCING
FOR SUBSIDENCE OVER THE AREA. SURFACE WINDS ARE EXPECTED TO RETURN
TO THE SOUTH TODAY WHICH MAY CAUSE THE WEAK FRONTAL BOUNDARY TO
LIFT NORTH ACROSS THE CWA THIS AFTERNOON. IT IS DIFFICULT TO
DETERMINE IF THIS WILL BE OF ANY CONSEQUENCE... BECAUSE THE RETURN
TO SOUTH WINDS UNDER MOSTLY SUNNY SKIES WILL MORE OR LESS
ELIMINATE ANY THERMAL GRADIENT/BAROCLINICITY ASSOCIATED WITH THE
FRONT.

BY DEFINITION THIS BOUNDARY WOULD NOT COUNT AS A FRONT ANYMORE
WITHOUT A DISCERNABLE THERMAL GRADIENT. HOWEVER...THERE WILL STILL
BE SOME SORT OF MOISTURE DISCONTINUITY ASSOCIATED WITH THE
BOUNDARY AS IT LIFTS NORTH TODAY...LIKELY RESULTING IN A SLIGHT
INCREASE IN RELATIVE HUMIDITY. NORMALLY THIS WOULD HAVE LITTLE
IMPACT ON THE FORECAST...BUT TODAY THE NAM AND RAP FORECAST
SOUNDINGS INDICATE THAT THE AFTERNOON INCREASE IN LOW-LEVEL
HUMIDITY IS SUFFICIENT TO RESULT IN AN ALMOST COMPLETE REMOVAL OF
THE CAP FROM THE FORECAST AREA DURING THE PEAK HEATING HRS OF THE
DAY. WITH NO CAP...IT IS POSSIBLE THAT SOME WEAK FORCING FOR
ASCENT COULD RESULT IN ISOLATED THUNDERSTORMS ACROSS NORTH TX BY
LATE THIS AFTERNOON.

AT THIS TIME...LEFT THE FORECAST DRY BECAUSE OF A LACK OF
DISCERNABLE FOCUS FOR THUNDERSTORM INITIATION THIS AFTERNOON. THE
SUBSIDENCE BEHIND THE UPPER LEVEL TROUGH IS EXPECTED TO BE
WEAK...BUT IN THE ABSENCE OF STRONG MESOSCALE FORCING FOR
ASCENT...THIS SHOULD BE SUFFICIENT TO KEEP US DRY DESPITE A NEARLY
UNCAPPED AFTERNOON THERMODYNAMIC ENVIRONMENT. OTHERWISE...WITH
MOSTLY SUNNY SKIES AND A RETURN TO SOUTH WINDS TODAY EXPECT
TEMPERATURES TO CLIMB INTO THE 80S FOR MOST LOCATIONS DESPITE THE
COOL START TO THE DAY THIS MORNING.

MONDAY AND TUESDAY...THE ECMWF/GFS/CANADIAN NOW ALL SHOW THE THAT
THE WESTERN EDGE OF OUR SOUTHEASTWARD MOVING TROUGH TODAY EVOLVES
INTO AN UPPER LEVEL CLOSED LOW OVER THE TX GULF COAST MONDAY INTO
TUESDAY. THIS WEAK UPPER LOW WILL LIKELY CAUSE CLUSTERS OF STORMS
TO DEVELOP EACH DAY ACROSS FAR SOUTH TX OR ALONG THE TX GULF
COAST...LIKELY WORKING TO REINFORCE THE UPPER LEVEL CIRCULATION
THROUGH THE PERIOD. DUE TO THE FORECAST POSITION OF THE UPPER LOW
TO OUR SOUTH...THIS FEATURE SHOULD ONLY REINFORCE UPPER LEVEL
SUBSIDENCE OVER THE CWA HELPING TO KEEP US DRY FOR EARLY THIS
WEEK. PERSISTENT SOUTHERLY FLOW WILL CONTINUE CAUSING SHALLOW GULF
MOISTURE TO REMAIN IN PLACE OVER THE CWA...BUT THUNDERSTORM
CHANCES SHOULD BE VERY LOW AS LONG AS THE UPPER LOW OVER THE GULF
COAST EVOLVES AS EXPECTED. AT ANY RATE...MOSTLY SUNNY SKIES AND
PERSISTENT SOUTHERLY FLOW WILL KEEP US ABOVE NORMAL FOR
TEMPERATURES WITH HIGHS IN THE MID TO UPPER 80S EACH DAY.

WEDNESDAY THROUGH FRIDAY...A POWERFUL UPPER LOW FROM THE GULF OF
ALASKA IS STILL EXPECTED TO MOVE SOUTHEAST OVER THE PLAINS
WEDNESDAY NIGHT INTO THURSDAY. THIS WILL SEND AN UNSEASONABLY
STRONG COLD FRONT SOUTH THROUGH THE PLAINS AND ACROSS NORTH TEXAS
LIKELY WEDNESDAY EVENING AND OVERNIGHT. AS LONG AS THE UPPER LOW
DIGS AS FAR SOUTH AS THE RED RIVER...WHICH IS ADVERTISED BY THE
OPERATIONAL ECMWF/GFS/CANADIAN...THERE SHOULD BE A NEARLY SOLID
LINE OF SHOWERS AND THUNDERSTORMS ACCOMPANYING THE FRONT. THE FRONT
IS EXPECTED TO MOVE THROUGH THE AREA VERY FAST...SO OVERALL
RAINFALL AMOUNTS WILL LIKELY BE SMALL...BUT MOST LOCATIONS SHOULD
AT LEAST SEE SOME LIGHT RAIN AS THE FRONT MOVES THROUGH THE AREA.
BUMPED UP POPS INTO THE 40 TO 50 PERCENT RANGE ALONG AND BEHIND
THE FRONT AS A RESULT. DID NOT GO HIGHER AT THIS TIME BECAUSE OF
UNCERTAINTY REGARDING THE TIMING OF THE FRONT. WHILE OPERATIONAL
MODELS ARE CONSISTENT WITH THE FRONTAL PASSAGE RIGHT NOW...THE
FRONT IS STILL AT LEAST 84 HRS OUT...AND OUR MEDIUM RANGE GUIDANCE
IS NOTORIOUSLY BAD AT PREDICTING THE TIMING OF STRONG COLD FRONTS.
THEREFORE WILL CONTINUE TO REFINE POPS AND THE TIMING OF THE FRONT
IN FUTURE FORECASTS.

SEVERE WEATHER CHANCES OUT AHEAD OR ALONG THE FRONT DO NOT LOOK
GREAT PRIMARILY BECAUSE OF THE PROGGED FAST MOTION OF THE FRONT
THROUGH THE PLAINS. SOME SEVERE WEATHER MAY BE ADDED TO THE
FORECAST AS THE FRONT GETS CLOSER...BUT FOR NOW THE OVERALL
PATTERN DOES NOT SEEM TO SUPPORT A REGIONAL OUTBREAK OF SEVERE
STORMS...SO WILL NOT HIGHLIGHT ANY SEVERE WEATHER IN PRODUCTS AT
THIS TIME. TEMPERATURES BEHIND THE FRONT ARE EXPECTED TO BE VERY
COLD FOR EARLY MAY...WITH RECORD LOW TEMPERATURES LIKELY BEHIND
THE FRONT THURSDAY NIGHT. RECORD LOWS THURSDAY NIGHT WILL HELP
KEEP TEMPERATURES COOL HEADED INTO THE WEEKEND.

THIS WEEKEND...THE ECMWF IS LESS BULLISH WITH ITS FORECAST OF A
BLOCKING PATTERN THAT WOULD KEEP THE UPPER LOW ANCHORED IN THE
CENTRAL PLAINS FOR SEVERAL DAYS. THE NAEFS IS ALSO LEANING MORE
TOWARDS THE UPPER LOW MOVING NORTHEAST OUT OF THE REGION BY EARLY
NEXT WEEK. THAT SAID...THE NAEFS MEAN AND THE LAST EVENING RUN OF
THE ECMWF BOTH KEEP GENERAL TROUGHINESS OVER THE CENTRAL
CONUS...MEANING TEMPERATURES WILL LIKELY BE NEAR OR MAYBE SLIGHTLY
BELOW SEASONAL NORMALS. AFTER NEAR RECORD OR RECORD LOWS THURSDAY
NIGHT/FRIDAY MORNING...THERE IS LITTLE PLACE FOR THE TEMPERATURES
TO GO BUT UP. TEMPERATURES WILL MODERATE BACK TOWARDS SEASONAL
NORMALS THIS WEEKEND INTO EARLY NEXT WEEK...AND NOT JUST BECAUSE
MOS GUIDANCE TRENDS TOWARDS CLIMATOLOGY OUT ON DAY 7. THICKNESS
AND HEIGHT RISES WILL HELP USHER IN WARMER TEMPERATURES AS LONG AS
THE UPPER LOW DOES MOVE NORTHEAST OF THE PLAINS BY EARLY NEXT
WEEK. THE EXTENDED FORECAST IS DRY FOR NOW...HOWEVER WITH GENERAL
CYCLONIC FLOW IN PLACE THERE WILL UNDOUBTEDLY BE SOME SMALL
FEATURES THAT NECESSITATE THE INCLUSION OF PRECIPITATION DURING
THIS PERIOD IN FUTURE FORECASTS. AT THIS TIME THERE IS JUST NOT
ENOUGH CONSISTENCY TO PLACE POPS IN ONE PERIOD OVER ANOTHER...SO
LEFT THE FORECAST DRY WITH 10 POPS IN PLACE FOR SEVERAL DAYS.

CAVANAUGH

&&

.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX  84  61  86  63  87 /  10   0   0   0   5
WACO, TX              84  58  84  60  86 /  10   0   0   0   5
PARIS, TX             79  55  83  58  84 /  10   0   0   0   5
DENTON, TX            83  58  87  59  87 /  10   0   0   0   5
MCKINNEY, TX          82  58  84  60  86 /  10   0   0   0   5
DALLAS, TX            83  62  86  64  87 /  10   0   0   0   5
TERRELL, TX           82  57  83  59  84 /  10   0   0   0   5
CORSICANA, TX         82  58  83  59  84 /  10   0   0   0  10
TEMPLE, TX            83  57  83  59  85 /  10   5   0   0   5
MINERAL WELLS, TX     83  58  86  59  87 /  10   0   0   0   5

&&

.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.

&&

$$






AREA FORECAST DISCUSSION

NWS LA CROSSE WI

 637 PM CDT MON APR 29 2013

.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 324 PM CDT MON APR 29 2013

THE MAIN FOCUS TONIGHT INTO TOMORROW IS ON THE CHANCES FOR
THUNDERSTORMS TO GO ALONG WITH HOW WARM IT WILL GET BEFORE A COLD
FRONT SWINGS THROUGH TOMORROW.

CURRENTLY...A SURFACE COLD FRONT HAS STALLED OUT ACROSS THE REGION
FROM NORTH CENTRAL WISCONSIN DOWN INTO EASTERN NEBRASKA WITH A
SURFACE LOW TRACKS ALONG THE US/CANADIAN BORDER IN SOUTHERN
SASKATCHEWAN. AS THIS LOW TRACKS EAST TONIGHT...THE FRONT WILL
TRANSITION TO A WARM FRONT AND LIFT NORTH TOWARD LAKE SUPERIOR BY
TOMORROW MORNING. LOW LEVEL MOISTURE TRANSPORT WILL NOSE UP ALONG
THE FRONT AND COULD LEAD TO SOME CONVECTIVE DEVELOPMENT ALONG THIS
BOUNDARY AS A RESULT. MODIFIED 29.18Z RAP SOUNDINGS WITH SURFACE
DEW POINTS IN THE MID 50S SHOW ABOUT 1000-1500 J/KG OF 0-3KM
MUCAPE POOLING ALONG THIS FRONT AS IT LIFTS NORTH OVERNIGHT. MUCH
OF THE DEEP LAYER SHEAR APPEARS TO BE IN THE LOW LEVELS UNDER THE
INVERSION AND NOT IN THE ELEVATED PORTIONS OF THE PROFILE. WITH
FREEZING LEVELS FAIRLY LOW ALONG THE NORTHERN PERIPHERY OF THE
FRONT...EXPECT THAT SOME STRONG TO ISOLATED SEVERE STORMS WILL BE
POSSIBLE OVERNIGHT. LARGE HAIL WILL LIKELY BE THE MAIN THREAT DUE
TO THE HIGH INSTABILITY AND STABLE BOUNDARY LAYER TO PREVENT THE
STRONGEST GUSTS FROM MAKING IT TO THE SURFACE.

STRONG SOUTHERLY WINDS AHEAD OF THE MAIN COLD FRONT THAT WILL BE
INTO MINNESOTA BY TOMORROW MORNING WILL HELP TO BRING TEMPERATURES
UP TOWARD 80 FOR MUCH OF THE REGION. THE 29.12Z NAM/GFS/ECMWF HAVE
MERGED ON A SOLUTION WITH THE TIMING OF THE FRONTAL PASSAGE WITH
IT GENERALLY EXTENDING FROM NORTH CENTRAL WISCONSIN TOWARD CENTRAL
IOWA BY 18Z TOMORROW AND NEAR THE IOWA/MINNESOTA/WISCONSIN TRIPLE
POINT BY 00Z WEDNESDAY. THIS TIMING OF THE FRONT COMING THROUGH
DURING THE DIURNAL PEAK HEATING IN THE AFTERNOON LEADS TO SOME
HIGHER CONFIDENCE IN THINKING THAT THE CONVECTION WILL DEVELOP
MAINLY ACROSS SOUTHWEST WISCONSIN AND NORTHEAST IOWA IN THE LATE
AFTERNOON AND EARLY EVENING HOURS. ONE CONCERN IS THE 850MB CAP
THAT APPEARS TO HOLD ON THROUGH AT LEAST THE EARLY AFTERNOON
HOURS. MODEL SURFACE DEW POINTS APPEAR TO AGAIN PLAY A FACTOR IN
GENERATING TOO MUCH INSTABILITY AND BREAKING THE CAP BY MID
AFTERNOON. THE 29.12Z NAM COMES IN WITH SURFACE DEW POINTS IN THE
LOW 60S WHILE MIXED LAYER DEW POINTS COME IN AROUND THE MID TO
UPPER 50S AND APPEAR MORE REASONABLE. THIS KNOCKS SURFACE BASED
CAPE DOWN FROM AROUND 1000-2000 J/KG WITH NO CIN DOWN TO HAVING
ABOUT 500 J/KG OF SBCAPE AND OVER 100 J/KG OF CIN WITH THE LOWER
DEW POINTS. THE FORCING ALONG THE FRONT SHOULD BE ENOUGH TO
DEVELOP SOME STORMS...BUT THE COVERAGE WILL BE DEPENDENT UPON HOW
MUCH OF THE CAP CAN BE ERODED AHEAD OF THE FRONT. DEEP SHEAR IS A
LITTLE BETTER ACROSS CENTRAL WISCONSIN AND IS MAINLY UNIDIRECTIONAL
SO STORM MODE SHOULD MAINLY BE MULTICELL CLUSTERS OR SOME BOWING
SEGMENTS.

.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 324 PM CDT MON APR 29 2013

TUESDAY NIGHT THROUGH THURSDAY

THIS FRONT WILL STALL OUT ACROSS SOUTHERN WISCONSIN AND EASTERN
IOWA INTO TUESDAY NIGHT WITH IT EVENTUALLY WEAKENING TOWARD
WEDNESDAY MORNING. AS THIS OCCURS...THE MAIN MID LEVEL TROUGH WILL
START CARVING OUT ACROSS THE CENTRAL PLAINS WITH A STRONG BAND OF
FRONTOGENESIS ALIGNING FROM NORTH TO SOUTH ACROSS THE UPPER
MISSISSIPPI VALLEY REGION. THIS WILL LEAD TO A PROLONGED PERIOD OF
MODERATE TO HEAVY PRECIPITATION...PARTICULARLY ACROSS SOUTHEAST
MINNESOTA AND NORTHEAST IOWA WEDNESDAY INTO THURSDAY. PRECIPITATION
WILL START OUT AS ALL RAIN ON WEDNESDAY...BUT THEN IS EXPECTED TO
COOL ENOUGH TO CHANGE OVER TO ALL SNOW IN SOUTHEAST MINNESOTA AND
NORTHEAST IOWA LATE WEDNESDAY NIGHT INTO THURSDAY. THE 29.12Z
NAM/GFS AND 29.15Z SREF ALL BACK THIS IDEA...THOUGH THE 29.12Z
ECMWF HAS COME BACK IN AS A WARM OUTLIER AND BRINGS THE MOST
UNCERTAINTY TO THIS FORECAST. THE WARM LAYER THAT THIS RUN OF THE
ECMWF PRODUCES TAKES THE MAIN SNOW BAND FURTHER TO THE WEST AND
OUT OF THE FORECAST AREA. THE CONSENSUS...OUTSIDE OF THE
ECMWF...WAS TO KEEP THE PRECIPITATION TYPE AS MAINLY SNOW ACROSS
SOUTHEAST MINNESOTA AND PORTIONS OF NORTH CENTRAL/EAST IOWA LATE
WEDNESDAY NIGHT INTO THURSDAY. SNOWFALL AMOUNTS ARE CURRENTLY
FORECAST TO MAINLY BE IN THE 2 TO 4 INCH RANGE...WITH A FEW SPOTS
THAT END UP UNDER THE MAIN BAND POTENTIALLY HITTING 6 INCHES OR
HIGHER. BECAUSE OF THE ECMWF...CONFIDENCE IS NOT HIGH ENOUGH YET
TO PUT OUT A WINTER STORM WATCH...BUT LATER SHIFTS WILL HAVE TO
WATCH FOR TRENDS ON THIS BAND AND WHERE IT ENDS UP.

THURSDAY NIGHT THROUGH MONDAY

THIS PERIOD IS CHARACTERIZED BY LOW CONFIDENCE AS THE LARGE CLOSED
LOW OVER THE CENTRAL U.S. IS STILL PRODUCING GREAT SPREAD WITHIN THE
NUMERICAL GUIDANCE. THESE ARE TRADITIONALLY HIGH SPREAD SITUATIONS
FOR THE MODELS. THUS...USED THE CONSENSUS BLEND AS IS FOR THE
PERIOD.

THE BIG PICTURE FOR THIS THE PERIOD BEGINS WITH THE STRONG
FRONTOGENESIS OVER THE FORECAST AREA WEAKENING WITH TIME AND WARMING
BEGINNING. THIS WARMING IS GENERALLY AGREED ON...WHICH WOULD CHANGE
ANY SNOW TO RAIN BY SATURDAY. THE LATEST 28.12Z ECMWF SUGGESTS A
WARMER SOLUTION TO THE ENTIRE PERIOD WITH ALL RAIN...EVEN IN WESTERN
MOST PART OF THE FORECAST AREA.

AS THE UPPER LOW SHIFTS EAST/NORTHEAST...A SURFACE LOW DEEPENS AND
ROTATES NORTH-NORTHWEST AND ELICITS HEAVY RAINFALL AHEAD OF IT ON
THE EAST SIDE OF THE UPPER LOW IN A RICH...OPEN GULF OF MEXICO FLOW.
THUS...SOME AREAS WILL SEE 1-2 INCHES OF RAIN INTO THE EARLY
WEEKEND...BUT THE BIG PROBLEM IS...WHERE. THE MODEL SPREAD WITH THIS
RAINFALL IS FROM KANSAS CITY MO /28.12Z GEM AND GFS/ TO THE LOCAL
AREA /28.12Z ECMWF/. IF THE EARLY PORTION OF THE FRONTOGENESIS
PRECIPITATION ON WED-THU IS ALL RAIN...THERE COULD BE 4 INCHES OF
RAINFALL THIS WEEK BY SUNDAY. THE HIGHEST CONFIDENCE OF THIS
OCCURRING LOOKS TO BE NEAR I-35 JUST EAST OF ANY SNOW BAND THAT
FORMS. THIS WOULD PROBABLY INCLUDE PARTS OF THE WESTERN FORECAST
AREA. BUT...THIS AGAIN IS LOW CONFIDENCE. IT SEEMS THE PATTERN SAYS
IT WILL HAPPEN BUT THE LOCATION IS A TOUGH CALL RIGHT NOW.

FOR THE SUNDAY AND MONDAY PERIOD...THE LOW SHOULD HAVE LESS AND LESS
IMPACT WITH WARMING TEMPERATURES AND MORE SCATTERED SHOWERY WEATHER.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING)
ISSUED AT 628 PM CDT MON APR 29 2013

SUMMARY...VFR CONDITIONS ARE EXPECTED THROUGH TUESDAY WITH
SOUTHERLY WINDS PICKING UP OVERNIGHT INTO TUESDAY MORNING.

DETAILS...
SKIES ARE CLEARING OUT AT THE TAF SITES WITH LOSS OF DAYTIME
HEATING ALLOWING CUMULUS TO DISSIPATE. ATTENTION NOW TURNS TO
SOUTHERLY WINDS PICKING UP ABOVE THE SURFACE AHEAD OF A LOW
PRESSURE TROUGH CROSSING WESTERN IOWA. THESE SOUTHERLY WINDS WILL
HELP PUSH A WARM FRONT ALONG I-80 THROUGH THE TAF SITES LATE
TONIGHT. IT APPEARS ANY SHOWER OR THUNDERSTORM ACTIVITY FIRING ON
THIS FRONT SHOULD STAY SOUTH AND EAST OF THE TAF SITES...THOUGH
KLSE MAY GET CLIPPED. INCLUDED A VCSH FOR 09-14Z AT KLSE FOR THIS
POTENTIAL. WITH THE INCREASING SOUTHERLY WINDS...ALSO INCLUDED A
PERIOD OF LOW LEVEL WIND SHEAR AT KLSE FROM 09-14Z. LOW LEVEL WIND
SHEAR IS MORE MARGINAL AT KRST...BUT IF GUSTS THAT ARE EXPECTED TO
DEVELOP AROUND 12Z DO NOT OCCUR...THEN LOW LEVEL WIND SHEAR WILL
OCCUR. LOOK FOR WINDS TO TURN SOUTHWESTERLY ON TUESDAY IN THE WAKE
OF THE WARM FRONT. COMBINED WITH MIXING AND THE APPROACH OF A COLD
FRONT FROM THE WEST...BOTH TAF SITES SHOULD GUST IN THE 20-30 KT
RANGE SHORTLY AFTER SUNRISE. COLD FRONT LOOKS TO PASS THROUGH KRST
AROUND 19Z AND MAYBE 23-00Z AT KLSE...SHIFTING WINDS MORE
WESTERLY. THERE IS A CHANCE OF SHOWERS AND THUNDERSTORMS IMPACTING
KLSE GIVEN THE FRONTAL TIMING OCCURRING RIGHT AFTER PEAK
HEATING...BUT THE CHANCE IS TOO LOW TO MENTION EVEN A VCSH AT THIS
TIME.

&&

.HYDROLOGY...
ISSUED AT 324 PM CDT MON APR 29 2013

HEAVY PRECIPITATION RATES ARE EXPECTED WEDNESDAY INTO FRIDAY AS A
STORM SYSTEM STALLS ACROSS THE REGION. IF THE PRECIPITATION FALLS
MAINLY AS RAIN...THERE IS THE POTENTIAL FOR 1 TO 3 INCHES TO FALL
BY FRIDAY...PARTICULARLY IN SOUTHEAST MINNESOTA AND NORTHEAST
IOWA. THIS ADDITIONAL RAINFALL WILL LEAD TO SOME RISES ON LOCAL
RIVERS AND STREAMS WHICH ARE ALREADY SOME WHAT HIGH DUE TO RECENT
PRECIPITATION AND THE SPRING SNOW MELT. CONFIDENCE IS NOT VERY
HIGH AT THIS POINT WITH WHERE THIS MAIN BAND WILL SET UP OR IF IT
WILL END UP AS SNOW...BUT THE GENERAL AREA THAT APPEARS TO TAKE
THE BRUNT OF THIS SYSTEM IS SOUTHEAST MINNESOTA AND NORTHEAST IOWA.

&&

.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&

$$

SHORT TERM...HALBACH
LONG TERM...HALBACH/BAUMGARDT
AVIATION...AJ
HYDROLOGY...HALBACH







AREA FORECAST DISCUSSION

NWS LA CROSSE WI

 558 PM CDT SUN APR 28 2013

.UPDATE...
ISSUED AT 558 PM CDT SUN APR 28 2013

CURRENTLY A NARROW LINE OF CONVECTION HAS INITIATED ALONG THE COLD
FRONT IN MINNESOTA FROM RUSH CITY TO MINNEAPOLIS AND ST JAMES.
LAPS ANALYSIS SHOWED MLCAPE VALUES OF 250-600 J/KG...MOSTLY RIGHT
ALONG THE FRONT. KMPX RADAR IMAGERY DOES SUGGEST THAT THE LINE OF
CONVECTION MAY HAVE JUMPED OFF THE FRONT RECENTLY...THOUGH.
MEANWHILE...OVER THE FORECAST AREA...SOME RIDGING HAS BUILT IN
ALOFT PER RAP ANALYSIS...HELPING TO CLEAR SKIES OUT.

PRECIPITATION CHANCES CONTINUE TO BE THE FOCUS TONIGHT. THE
28.12Z REGIONAL CANADIAN AND 28.19/20/21Z HRRR RUNS HAVE BEEN
DOING A GREAT JOB WITH THE CONVECTION ON THE FRONT. ALL OF THESE
MODELS SUGGEST A WEAKENING TREND AS THEY PUSH EAST THROUGH THE
EVENING. THIS MAKES SENSE AS THEY SEEM TO BE DIURNALLY ASSISTED
WITH THE CAPE THAT BUILT AHEAD OF THE FRONT. ONCE DIURNAL COOLING
TAKES PLACE...INSTABILITY WILL WANE AND THUS THE STORMS AS WELL.
PERHAPS A FEW MAY MAKE IT INTO NORTHWEST SECTIONS OF THE FORECAST
AREA...ENOUGH TO WARRANT 20-30 PERCENT CHANCES...LOWER THAN THE
PREVIOUS FORECAST. SEEING SOME OF THE CONVECTION JUMPING OFF THE
FRONT ALSO IS WORRISOME TO HOLD IT TOGETHER BECAUSE INSTABILITY
WANES PRETTY QUICK. THERE COULD BE A GENERALLY DRY PERIOD THEN
UNTIL LATE IN THE NIGHT...WHICH IS WHEN THE COLD FRONT SLIDES INTO
THE AREA. BEHIND THIS FRONT...TWO FORCING MECHANISMS SHOULD HELP
DEVELOP PRECIPITATION...

1. A SHORTWAVE OVER NORTHWEST WYOMING PUSHING EAST INTO EASTERN
SOUTH DAKOTA BY LATE IN THE NIGHT...YIELDING SOME DPVA DOWNSTREAM
INTO NORTHERN IOWA AND SOUTHERN MINNESOTA.
2. MID-LEVEL FRONTOGENESIS IN PLACE BEHIND THE FRONT. RADAR SHOWS
THIS FRONTOGENESIS ALREADY BY A BAND OF SHOWERS FROM NEAR ABERDEEN
SOUTH DAKOTA TO DULUTH MN.

THUS STILL HAVE KEPT SOME HIGHER PRECIPITATION CHANCES FOR LATE IN
THE NIGHT INTO MONDAY MORNING...ESPECIALLY OVER NORTHEAST IOWA
WHERE CONSENSUS EXISTS FROM ALL MODELS FOR PRECIPITATION TO OCCUR.

&&

.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 327 PM CDT SUN APR 28 2013

THE MAIN FOCUS FOR TONIGHT INTO MONDAY IS WITH A TWO TIERED SYSTEM
AND THE PRECIPITATION CHANCES THAT COME ALONG WITH IT. THE FIRST
WAVE APPROACHES THE REGION THIS EVENING IN THE FORM OF A SURFACE
COLD FRONT THAT IS CURRENTLY ANALYZED IN WESTERN MINNESOTA. MUCH
OF THE 28.12Z GUIDANCE ARE FORECASTING TOO HIGH OF SURFACE DEW
POINTS...IN THE LOW TO MID 50S WHEN CURRENT OBS SHOW MID
40S...WHICH IN TURN IS MAKING THE INSTABILITY IN THESE MODELS TOO
HIGH. THIS IS CAUSING A LOT OF THE GUIDANCE TO COME UP WITH A
LARGE AREA OF CONVECTION THAT DEVELOPS THIS EVENING AHEAD OF THE
FRONT AND BRINGS IT THROUGH THE REGION IN AN DIMINISHING FASHION
AS THE INSTABILITY WANES OVERNIGHT. THAT TREND IS OKAY...BUT AM
NOT VERY CONFIDENT THAT THIS CONVECTION WILL BE AS WIDESPREAD AS
GUIDANCE SUGGESTS. THE 28.12Z ARW EAST/WEST MODELS SEEM TO DO THE
BEST JOB AT LIMITING THE CLIMBING DEW POINTS AND KEEP 0-3KM MUCAPE
IN THE 200-400 J/KG RANGE OVERNIGHT AND MATCHES BEST TO THESE
THOUGHTS OF MORE SCATTERED THAN WIDESPREAD CONVECTION OVERNIGHT.
WITH JUST A FEW HUNDRED J/KG OF CAPE TO WORK WITH...HAVE LIMITED
THE THUNDER COVERAGE TO BEING ISOLATED TONIGHT. THERE IS SOME
INCREASING MID LEVEL WINDS AS THIS FRONT APPROACHES...SO SHEAR MAY
BE DECENT ENOUGH THAT...COMBINED WITH SOME LOW FREEZING
LEVELS...THERE COULD BE SOME SMALL HAIL THAT OCCURS WITH A FEW OF
THE STORMS BUT NOTHING THAT WOULD BE CONSIDERED SEVERE.

THE MAIN MID LEVEL TROUGH DIVES DOWN ACROSS THE REGION TOMORROW
MORNING AND IS EXPECTED TO DEVELOP A MORE WIDESPREAD AREA OF
CONVECTION ALONG THE WEAKENING SURFACE FRONT. THIS MID LEVEL
TROUGH IS CURRENTLY NOTED ON GOES WATER VAPOR IMAGERY EXTENDING
EAST TO WEST FROM SOUTHWEST ONTARIO INTO SOUTHEAST MONTANA. AS
THIS TROUGH SAGS SOUTHEAST TOMORROW...SOME DIFFERENCES ARISE
BETWEEN THE 28.12Z MESO AND SYNOPTIC SCALE MODELS. THE 28.12Z
NAM/GFS/ECMWF/GEM ALL SHOW SOME STRONG LOW LEVEL MOISTURE
TRANSPORT NOSING UP INTO EASTERN IOWA BY LATE MORNING THAT ALSO
BRING SURFACE DEW POINTS UP INTO THE 60S AHEAD OF THE SURFACE/LOW
LEVEL LOW. THIS BRINGS SFC/0-3KM MUCAPE UP TO ABOVE 2000 J/KG AND
DEVELOPS A WIDESPREAD AREA OF CONVECTION ALONG THE NOSE OF THE LOW
LEVEL JET. MEANWHILE...28.12Z ARW/NMM ARE MUCH MORE TAME WITH THE
MOISTURE RETURN/DEW POINTS/INSTABILITY AND CONVECTIVE DEVELOPMENT.
HAVE KEPT THE LIKELY PRECIPITATION CHANCES GOING FOR NORTHEAST
IOWA/SOUTHWEST WISCONSIN TOMORROW WHERE THIS CONVECTION IS A BIT
MORE CERTAIN...BUT THINK THAT THE SYNOPTIC MODELS ARE A TAD
OVERDONE. IF THE MOISTURE RETURN CAN DEVELOP AS ADVERTISED ON
THESE SYNOPTIC MODELS...WILL HAVE TO WATCH FOR A BRIEF PERIOD OF
SEVERE STORMS THAT COULD PRODUCE SOME LARGE HAIL/GUSTY WINDS.

.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 327 PM CDT SUN APR 28 2013

THE 28.12Z GUIDANCE REMAINS STUBBORN WITH NO DIFFERING TRENDS
NOTED BETWEEN THIS RUN AND THE 28.00Z RUN FOR A COLD FRONT THAT
WILL MOVE THROUGH ON TUESDAY. AHEAD OF THIS FRONT
ON MONDAY NIGHT...THE LOW LEVEL JET/MOISTURE TRANSPORT WILL PUSH
BACK TO THE NORTH AHEAD OF THE FRONT AND COULD SPARK OFF SOME
CONVECTION AS IT LIFTS NORTHWARD. FOR TUESDAY...THE 28.12Z ECMWF
REMAINS THE SLOW OUTLIER WITH THE EASTWARD PROGRESSION OF THE
SURFACE COLD FRONT ON TUESDAY AND PRESENTS THE WARMEST SOLUTION
FOR TEMPERATURES. BY 00Z WEDNESDAY...THE 28.12Z NAM/GFS BOTH HAVE
THIS FRONT INTO NORTHWEST ILLINOIS WHILE THE ECMWF STILL HAS IT
BACK IN NORTHWEST WISCONSIN/JUST CLEARING SOUTHEAST MINNESOTA.
WITH LOW LEVEL MOISTURE TRANSPORT INCREASING AHEAD OF THIS FRONT
ON TUESDAY AND DECENT LOW LEVEL LIFT ALONG THE FRONT...SOME SEVERE
WEATHER IS POSSIBLE IN THE WARM SECTOR TUESDAY. WHERE THAT WARM
SECTOR IS ALIGNED BY MID AFTERNOON IS UNCERTAIN STILL...BUT WILL
HAVE TO WATCH FOR WHICH WAY THIS FRONT TRENDS. DUE TO THERE NOT
BEING MUCH IN THE WAY OF CHANGES IN THE GUIDANCE...HAVE NOT MADE
MANY ADJUSTMENTS TO THE GOING FORECAST OVER THIS PERIOD.

AFTER THIS COLD FRONT MOVES THROUGH BY TUESDAY NIGHT IT WILL THEN
STALL OUT TO THE EAST OF THE REGION AS A MID TO UPPER LEVEL TROUGH
AMPLIFIES ACROSS THE CENTRAL US TOWARD THE MIDDLE OF THE WEEK.
THIS TROUGH GETS CUT OFF FROM THE FLOW WITH THE CORE OF THE LOW
SITTING RIGHT OVER THE UPPER MISSISSIPPI RIVER VALLEY THROUGH NEXT
WEEKEND. STRONG FORCING WILL DEVELOP ON WEDNESDAY IN RESPONSE TO
A STRENGTHENING LOW TO MID LEVEL BAND OF FRONTOGENESIS THAT FORMS
TO THE WEST OF THE SURFACE FRONT. WHILE THE 28.12Z ECMWF CONTINUES
TO BE AN OUTLIER WITH A WARMER SOLUTION FROM 700MB DOWN TO THE
SURFACE ON WEDNESDAY AND WANTS TO KEEP THE PRECIPITATION AS
MAINLY RAIN TO BEGIN...IT DOES APPEAR TO BE COMING AROUND TO BEING
COLD ENOUGH TO PRODUCE ALL SNOW FROM WEDNESDAY NIGHT INTO EARLY
THURSDAY. THIS IS ESPECIALLY THE CASE ACROSS SOUTHEAST MINNESOTA
AND NORTHEAST IOWA WHERE SOME SIGNIFICANT SNOW RATES AND
ACCUMULATIONS ARE POSSIBLE. 28.12Z GFS THERMAL PROFILES SHOW THAT
THE MAIN QUESTION IS WITH SURFACE TEMPERATURES AND HOW MUCH THEY
WILL COOL AS THE PRECIPITATION COMMENCES ON WEDNESDAY. THE HIGHEST
CONFIDENCE FOR ANY SNOW ACCUMULATION AT THIS POINT IS WEDNESDAY
NIGHT INTO THURSDAY MORNING AS THE COLDEST LOW LEVEL AIR COMES IN.
CURRENT FORECAST TEMPERATURES FOR WEDNESDAY INTO THURSDAY MAY END
UP BEING TOO HIGH...BUT FOR NOW HAVE DONE A SEMI-BLEND OF THE
28.12Z GFS/ECMWF.

BEYOND THIS FEATURE...THE 28.12Z GFS IS FASTER WITH CLEARING OUT
THE PRECIPITATION ON THURSDAY COMPARED TO THE ECMWF AND GEM WHICH
LINGER THE FRONTOGENETIC BAND OVER THE REGION THROUGH THE REST OF
THE WEEK AS THE MID LEVEL LOW GETS CUT OFF FROM THE FLOW. THIS MID
LEVEL AND SURFACE LOW RETROGRADE BACK INTO IOWA/MISSOURI BY NEXT
WEEKEND...WHICH MAY HELP TO BRING SOME SLIGHTLY WARMER AIR BACK
INTO THE REGION. OVERALL...EXPECTING PERIODS OF PRECIPITATION AS
THIS LOW SITS AND SPINS WITH SHORTWAVE TROUGHS ROTATING AROUND IT
THROUGH NEXT WEEK.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1254 PM CDT SUN APR 28 2013

A COLD FRONT WILL MOVE SOUTHEAST INTO THE AREA TONIGHT AND THEN
STALL NEAR THE INTERSTATE 90 CORRIDOR. THIS FRONT WILL BE THE
FOCUS FOR THE DEVELOPMENT OF SHOWERS AND THUNDERSTORMS. THE BEST
CHANCE OF THUNDERSTORMS LOOKS TO BE FROM 29.03Z TO 29.09Z AT KRST...
AND FROM 29.06Z AND 29.10Z AT KLSE. AS THE LOW LEVELS SLOWLY
SATURATE...VISIBILITIES WILL BECOME MVFR. THIS SHOULD OCCUR AROUND
29.09Z AND THEN CONTINUE THROUGH THE REMAINDER OF THE MORNING.
HOW LOW THE CEILINGS WILL FALL ALONG AND IN THE WAKE OF THE FRONT
IS STILL UNCERTAIN. THE BUFKIT SOUNDINGS SUGGEST THAT CEILINGS
WILL BE IFR/MVFR AT KRST AND MVFR AT KLSE AFTER 29.09Z...BUT THESE
MODELS ALSO SHOW A MUCH LARGER AREA OF PRECIPITATION THAN THE MESO
MODELS. THIS AREAL EXTENT OF THE PRECIPITATION WILL GREATLY AFFECT
THE CEILINGS. AS A RESULT...JUST INTRODUCED A BROKEN MVFR DECK AT
KRST AND LEFT THE CEILINGS VFR AT KLSE.


&&

.HYDROLOGY...
ISSUED AT 327 PM CDT SUN APR 28 2013

POTENTIAL EXISTS FOR SOME HEAVY RAINFALL THIS WEEK AS A SYSTEM
STALLS OUT ACROSS THE REGION TOWARD MID WEEK. THERE IS SOME
QUESTION ABOUT WHAT THE PRECIPITATION TYPE WILL BE...BUT THE
FORECAST GUIDANCE IS SUGGESTING RAINFALL AMOUNTS OF OVER AN INCH
BY THE END OF THE WEEK. SHOULD THIS PRECIPITATION FALLS AS
RAIN...THERE COULD BE AN INCREASE IN LOCAL RIVER LEVELS.

&&

.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&

$$

UPDATE...AJ
SHORT TERM...HALBACH
LONG TERM...HALBACH
AVIATION...BOYNE
HYDROLOGY...HALBACH








AREA FORECAST DISCUSSION

NWS MIAMI FL

 119 AM EDT TUE APR 30 2013

.AVIATION...VFR WILL PREVAIL. HOWEVER, A FEW SHOWERS ARE POSSIBLE
ALONG THE ATLANTIC COAST THIS MORNING AND SCATTERED TSTORMS ARE
EXPECTED THIS AFTERNOON. HRRR SHOWS SOME SHOWER DEVELOPMENT ALONG
THE ATLANTIC COAST THIS MORNING AND A FEW ARE ALREADY DEVELOPING,
SO PLACED VCSH ALL EAST COAST TERMINALS FOR THE MORNING. KEPT VCTS
ALL TERMINALS FOR THIS AFTERNOON-EVENING. BRIEF IFR WOULD BE
POSSIBLE SHOULD A DIRECT TSTORM IMPACT OCCUR, AND A COUPLE OF THE
STORMS COULD PRODUCE STRONG DOWNBURST WINDS, BUT PROBABILITIES ARE
TOO LOW TO MENTION ANYTHING MORE THAN VCTS AT THIS TIME. /GREGORIA

&&

.PREV DISCUSSION... /ISSUED 825 PM EDT MON APR 29 2013/

UPDATE...
EARLIER SHOWERS AND THUNDERSTORMS HAVE QUICKLY DISSIPATED ACROSS
THE ENTIRE SOUTH FLORIDA AREA WITH LOSS OF HEATING. DECREASED POPS
AREA WIDE TO ACCOUNT FOR THIS. CURRENT RADAR SHOWS A CLUSTER OF
SHOWERS AND THUNDERSTORMS MOVING NORTH FROM CUBA INTO THE FLORIDA
STRAITS. LATEST LOCAL HIGH RESOLUTION MODELS DEPICT SOME OF THIS
ACTIVITY MOVING INTO THE GULF WATERS OVERNIGHT AND INTO EARLY
TUESDAY MORNING. WILL KEEP SLIGHT CHANCE POP ACROSS GULF AND
ATLANTIC WATERS OVERNIGHT. BELIEVE PARTLY TO MOSTLY CLOUDY SKIES
WILL PREVAIL OVERNIGHT WHICH SHOULD KEEP FOG FORMATION CHANCES
LOW. KEPT ANY MENTION OUT OF THE FORECAST FOR NOW. BELIEVE ANY
FOG THAT DOES DEVELOP ACROSS INTERIOR AREAS SHOULD BE VERY
SHALLOW.

PREV DISCUSSION... /ISSUED 806 PM EDT MON APR 29 2013/

AVIATION...
THE WEATHER IS QUIETING DOWN THIS EVENING AFTER A ROUND OF SHOWERS
AND THUNDERSTORMS THIS AFTERNOON. CONDITIONS SHOULD BE VFR TONIGHT
WITH WINDS BECOMING LIGHT AND VARIABLE. TOMORROW WILL SEE A REPEAT
OF TODAY. WINDS WILL PICKUP IN THE MORNING OUT OF THE SOUTHEAST
AROUND 10 KTS AND SHOWERS WILL DEVELOP. THEN, IN THE AFTERNOON,
SCATTERED THUNDERSTORMS WILL DEVELOP ACROSS SOUTH FLORIDA. GIVEN
THE NATURE OF CONVECTION AND THE UNPREDICTABILITY, HAVE PUT VCTS
IN ALL TAF SITES AT 18Z.

PREV DISCUSSION... /ISSUED 234 PM EDT MON APR 29 2013/

SYNOPSIS...
A LOW PRESSURE TROUGH EXTENDING FROM THE GULF OF MEXICO THROUGH
THE MISSISSIPPI VALLEY WILL REMAIN IN PLACE MOST OF THIS WEEK. FOR
SOUTH FLORIDA...WARM...MOIST AND UNSTABLE AIR AHEAD OF THIS TROUGH
WILL CREATE SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS
THROUGH THE PERIOD.

SHORT TERM /TONIGHT THROUGH WEDNESDAY NIGHT/...
SHOWERS AND THUNDERSTORMS HAVE DEVELOPED OVER THE EVERGLADES EARLY
THIS AFTERNOON. MOVEMENT IS NORTH AND EAST AND EXPECT COVERAGE TO
CONTINUALLY INCREASE THROUGH LATE AFTERNOON. THE MAJORITY OF
ACTIVITY SHOULD REMAIN OVER THE INTERIOR...BUT AT LEAST SCATTERED
SHOWERS AND A FEW THUNDERSTORMS ARE EXPECTED FOR BOTH EASTERN
METRO AREAS AND NAPLES. CAPE VALUES IN EXCESS OF 1000 J/KG HAS
OVERCOME MODEST MID-LEVEL INHIBITION. DESPITE WEAK LAPSE RATES AND
UNIMPRESSIVE 0-6KM SHEAR...THE STRONGEST UPDRAFTS WILL BE CAPABLE
OF PRODUCING HAIL AS WELL AS STRONG/POSSIBLY DAMAGING
MICROBURSTS...PARTICULARLY NEAR OUTFLOW/SEABREEZE INTERACTIONS. WITH
PWAT VALUES APPROACHING 1.5 INCHES...TORRENTIAL DOWNPOURS WILL
OCCUR AND LOCALIZED FLOODING CANT BE RULED OUT. OUTSIDE OF
CONVECTION...TEMPERATURES ARE IN THE 80S.

PRECIPITATION THIS AFTERNOON IS A RESULT OF A MOIST ATMOSPHERE AND
OVERALL DIFFLUENT FLOW IN ADVANCE OF MID/UPPER-LEVEL TROUGH OVER
THE MISSISSIPPI VALLEY. IN ADDITION...H3 JET MAX MOVING THROUGH
GULF WILL PLACE SOUTH FLORIDA IN CONVECTIVELY-FAVORED ASCENT BY
THIS EVENING. WITH INSTABILITY DIURNALLY WANING OVERNIGHT...SEVERE
STORMS ARE NOT EXPECTED...BUT SHOWERS MAY CONTINUE AND TSTMS ARE
POSSIBLE OVER THE WARM ATLANTIC WATERS TONIGHT.

ALOFT...SYNOPTIC PATTERN WILL STALL THROUGH AT LEAST MID-WEEK.
THUS...SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS ARE
FORECAST...ESPECIALLY DURING THE AFTERNOONS...WITH A SIGHT RISK
FOR STRONG/SEVERE...CONVECTION.  NEAR THE SURFACE...A LOW PRESSURE
TROUGH OVER NORTHERN FLORIDA TODAY WILL GRADUALLY MOVE SOUTH AND
INTO SOUTH FLORIDA BY WEDNESDAY. THIS MAY SERVE TO INCREASE
CONVECTION ON WEDNESDAY...BUT INCREASED CLOUDS COULD LIMIT
INSTABILITY AND STORM INTENSITY. TEMPERATURES DURING THE PERIOD
WILL BE SLIGHTLY ABOVE AVERAGE.

LONG TERM /THURSDAY THROUGH SUNDAY/...
THE LONG RANGE MODELS ARE SHOWING TWO UPPER LEVEL LOWS DEVELOPING
LATE THIS WEEK INTO NEXT WEEKEND. ONE OF THE UPPER LEVEL LOWS
SHOULD DEVELOP OVER THE CENTRAL UNITED STATES...WHILE THE OTHER
UPPER LEVEL LOW SHOULD DEVELOP OVER THE MID ATLANTIC WATERS. THIS
WILL ALLOW FOR THE RIDGE OF HIGH PRESSURE TO DEVELOP OVER THE
SOUTHEASTERN UNITED STATES AND INTO THE FLORIDA PENINSULA. THIS IN
TURN WILL ALLOW FOR DRIER AIR TO WORK INTO SOUTH FLORIDA FROM THE
NORTH. SO WILL SHOW A GRADUAL LOWERING OF POPS LATE THIS WEEK
INTO NEXT WEEKEND WITH THE BEST CHANCE STILL OVER THE INTERIOR
AREAS EACH DAY...DUE TO THE SEA BREEZES DEVELOPING AND PUSHING
INLAND EACH DAY.

MARINE...
SOUTHEAST WINDS OF 10-15 KTS TODAY WILL BECOME SOUTH AT 10-15 KTS
ON TUESDAY. A WEAK LOW LEVEL BOUNDARY MAY SHIFT WINDS TO THE NORTH
ON WEDNESDAY. THROUGH AT LEAST MID-WEEK...SCATTERED TO NUMEROUS
SHOWERS AND THUNDERSTORMS ARE EXPECTED. SOME OF THIS ACTIVITY MAY
BE STRONG...AND SPECIAL MARINE WARNINGS MAY BE NEEDED.

FIRE WEATHER...
RELATIVE HUMIDITY VALUES WILL BE ABOVE 40 PERCENT MOST OF THIS
WEEK AS A MOIST AND UNSTABLE ATMOSPHERE RESIDES OVER SOUTH
FLORIDA. PATCHY INLAND FOG CANT BE RULED OUT EACH OVERNIGHT.

&&

.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH  71  84  70  82 / 40 50 40 60
FORT LAUDERDALE  74  85  72  84 / 30 50 40 50
MIAMI            73  86  72  85 / 30 50 40 50
NAPLES           70  86  69  84 / 20 40 40 40

&&

.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&

$$






AREA FORECAST DISCUSSION

NWS CHICAGO/ROMEOVILLE IL

 253 AM CDT TUE APR 30 2013

.DISCUSSION...

939 PM...EVENING UPDATE...CONVECTIVE TRENDS OVERNIGHT REMAIN
UNCERTAIN. MASSIVE STORM DEVELOPED SOUTHWEST OF DBQ 1-2 HOURS AGO
PRODUCING UP TO TENNIS BALL SIZED HAIL. THIS STORM HAS SINCE
WEAKENED AS IT MOVES INTO SOUTHWEST WI. ADDITIONAL ACTIVITY ALSO
BUBBLING ACROSS CENTRAL IA AND SHORT TERM/HIGH RES GUIDANCE SEEMS
TO FOCUS ON THIS AREA FOR FURTHER DEVELOPMENT LATE THIS EVENING AS
THE LOW LEVEL JET DEVELOPS/INCREASES...WITH THIS ACTIVITY LIFTING
NORTH INTO SOUTH/CENTRAL WI OVERNIGHT. AT THE SAME TIME...DECENT
AGREEMENT FOR ADDITIONAL DEVELOPMENT OVER LAKE MICHIGAN WHICH
DEVELOPS SOUTHEAST INTO NORTHWEST INDIANA IN THE PREDAWN HOURS
TOWARD SUNRISE. WITH EITHER OF THESE SCENARIOS PLAUSIBLE...ITS
POSSIBLE THAT MUCH OF THE CWA COULD REMAIN DRY OVERNIGHT AND INTO
TUESDAY MORNING. BUT ISOLATED ACTIVITY CURRENTLY DEVELOPING
SOUTHEAST OF DBQ WHICH WILL NEED TO BE MONITORED IN THE SHORT
TERM. THUS GIVEN LOW CONFIDENCE...HAVE MAINTAINED LOW CHANCE POPS
FOR AREAS GENERALLY ALONG/NORTH OF THE I-80 CORRIDOR BUT HAVE
INCLUDED SOME TIMING/TRENDS IN THE GRIDS...ALL OF WHICH WILL
LIKELY NEED ADJUSTMENTS THROUGH THE NIGHT. ANY ORGANIZED CELLS
THAT DEVELOP WILL HAVE THE POTENTIAL TO PRODUCE LARGE HAIL. CMS

//PREV DISCUSSION...
323 PM CDT

MAIN FORECAST CONCERNS ARE TRYING TO TIME PERIODS OF PRECIP
POTENTIAL THROUGH MID-WEEK...AND WARM TEMPS DURING THE SAME TIME
PERIOD. BEYOND MID-WEEK...CLOSED UPPER LOW LOOKS TO INFLUENCE LOCAL
WEATHER FOR SEVERAL DAYS WITH COOLER TEMPS AND PERSISTENT THREAT OF
SCATTERED SHRA/TSRA.

NEAR TERM...TONIGHT-WEDNESDAY

SMALL CLUSTER OF ISOLATED SHRA/TSRA CONTINUES TO PROPAGATE EAST
ALONG THE IL/WI BORDER THIS AFTERNOON...ON NOSE OF 25-30 KT LOW
LEVEL JET PER LOCAL VWP AND ASSOCIATED WARM/MOIST ADVECTION. HAS NOT
BEEN MUCH REDEVELOPMENT UPSTREAM OF THIS CLUSTER...THOUGH IT HAS
BEEN QUITE PERSISTENT IN MAINTAINING AT LEAST ONE FAIRLY STRONG TSRA
CORE FOR SEVERAL HOURS. EXPECT THIS WILL CONTINUE TO MOVE EAST
ACROSS BOONE/MCHENRY AND LAKE COUNTIES OVER THE NEXT COUPLE OF HOURS
AND MAY PRODUCE SOME ISOLATED NICKEL-QUARTER SIZED HAIL SOUTH OF THE
WI STATE LINE. LOOKING AT THE BIGGER PICTURE...GOES VAPOR IMAGERY
DEPICTS ONE MID-LEVEL SHORT WAVE MOVING ACROSS WI/NORTHERN GREAT
LAKES REGION THIS AFTERNOON...WITH ANOTHER UPSTREAM ACROSS KS/NEBR.
IT WOULD APPEAR THAT THERE WOULD BE A LULL IN PRECIP DEVELOPMENT
BETWEEN THESE TWO FORCING MECHANISMS THIS EVENING...WITH THE PLAINS
WAVE APPROACHING THE AREA LATE TONIGHT. HOWEVER...SEVERAL HIGH-RES
CONVECTION-ALLOWING MODELS INDICATE POTENTIAL REDEVELOPMENT OF
SHRA/TSRA ACROSS EASTERN IA INTO NORTHERN IL THIS EVENING...WHERE
WEAK LOW LEVEL JET AND MOIST/INSTABILITY AXIS LINGER. MID-AFTERNOON
VISIBLE SATELLITE IMAGERY DOES INDICATE SOME CU ATTEMPTING TO FORM
ACROSS SOUTHEAST IA WITHIN SFC MOIST AXIS...THOUGH IT IS NOT TOO
IMPRESSIVE AT THIS TIME. SPC RAP MESOANALYSIS DATA DOES DEPICT AN
AXIS OF 1000-2000 J/KG MLCAPE ACROSS SE IA...THOUGH ALSO INDICATES
SOME 75-100 J/KG OF CIN. BASED ON PRESENCE OF MOIST/UNSTABLE AXIS
AND HIGH-RES GUIDANCE TRENDS OF REDEVELOPMENT HAVE CHOSEN TO
MAINTAIN CHANCE POPS FOR SHRA/TSRA ACROSS MAINLY AREAS NORTH OF I-80
THROUGH TONIGHT...ESPECIALLY WEST THIS EVENING AND SPREADING FARTHER
EAST LATER TONIGHT. LACK OF STRONGER SHORT WAVE FORCING KEEPS
CONFIDENCE ON THE LOW SIDE THIS EVENING HOWEVER...WITH A LITTLE
HIGHER CONFIDENCE OVERNIGHT AS PLAINS SHORT WAVE APPROACHES AND
PASSES ACROSS THE AREA EARLY TUESDAY MORNING.

ON TUESDAY...ONCE MORNING SHORT WAVE PASSES IT APPEARS FORCING FOR
ORGANIZED PRECIP WILL BE LACKING. COLD FRONT TO OUR WEST IS NOT
EXPECTED TO MAKE PROGRESS EAST AS UPPER FLOW AMPLIFIES IN RESPONSE
TO STRONG MID/UPPER LEVEL JET MOVING INTO THE PAC NW. THIS
AMPLIFICATION INDUCES SURFACE LOW PRESSURE DEVELOPING AND LIFTING
NORTHEAST INTO ONTARIO. THIS ALLOWS STRONGER LOW LEVEL SOUTH FLOW
ACROSS IL/IN...WITH WARMER TEMPS. COMBINATION OF LOW LEVEL THERMAL
PROGS...850 MB DERIVED TEMP CLIMATOLOGY AND MOS NUMBERS SUGGEST
AFTERNOON HIGHS 80-85...PROVIDED MORNING CLOUD COVER MOVES OUT AS
EXPECTED. 850 MB TEMPS JUST A BIT LOWER WEDNESDAY AS UPPER TROUGH
CONTINUES TO AMPLIFY AND SURFACE COLD FRONTAL TROUGH DRIFTS EAST
INTO THE REGION...THOUGH ESPECIALLY EASTERN AREAS WILL LIKELY BE
BACK INTO THE LOWER 80S WHILE CLOUDS/PRECIP CHANCES INCREASE FROM
THE WEST. VARIOUS GUIDANCE SOLUTIONS SHOW SOME MINOR DIFFERENCES
WITH TIMING OF ARRIVAL OF THE FRONT AND ASSOCIATED PRECIP...THOUGH
ALL BASICALLY INCREASE POPS FAIRLY QUICKLY ACROSS THE CWA WEDNESDAY
NIGHT.

LONGER TERM...THURSDAY-MONDAY

MODELS CONTINUE THE TREND OF THE AMPLIFYING UPPER TROUGH BECOMING
CUT OFF FROM THE MAIN JET AND BECOMING A CLOSED LOW OVER THE
MID/LOWER MISSOURI VALLEY...THEN DRIFTING THIS CIRCULATION TO THE
EAST/NORTHEAST THROUGH THE REMAINDER OF THE FORECAST PERIOD. QUITE A
BIT OF SPREAD REMAINS IN ENSEMBLE SOLUTIONS...AS WELL AS THE
OPERATIONAL RUNS OF THE ECMWF/GFS. HAVE MADE LITTLE CHANGE TO GOING
FORECAST IN THE EXTENDED PERIOD AT THIS POINT BASED ON FAIRLY LOW
CONFIDENCE GIVEN MODEL SPREAD...AND THE NOTORIOUSLY PROBLEMATIC JOB
OF FORECASTING CUT-OFF CLOSED LOW DETAILS DAYS 4 AND BEYOND. OVERALL
HAVE MAINTAINED A FORECAST UTILIZING A BLEND OF GUIDANCE FOR TEMPS
AND POPS. WHILE COOLER...LOOKS LIKE 50S/60S FOR HIGHS AND 40S FOR
LOWS DEPENDING ON CLOUD COVER AND SHOWER COVERAGE. POPS ARE LIKELY
OVERDONE A BIT...AND WILL LIKELY BE ABLE TO BETTER DETAIL THEM IN
COMING DAYS AS THE PATH OF THE UPPER LOW BECOMES MORE CLEAR.

RATZER

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 06Z...

* LOW CHANCES FOR SHRA/TSRA OVERNIGHT.
* GUSTY SOUTHERLY WINDS AROUND 25KT OR SO TUESDAY AFTERNOON.

BMD

//DISCUSSION...UPDATED 06Z...

LOW PRESSURE LIES OVER THE DAKOTAS THIS EVENING WITH SOUTHERLY FLOW
IN PLACE ACROSS NORTHERN ILLINOIS. MODERATE INSTABILITY LIES OVER
THE AREA THIS EVENING HOWEVER THE BEST FOCUS FOR FORCING IS EXPECTED
TO REMAIN WEST AND NORTHWEST OF THE TERMINALS THROUGH THE NIGHT. A
60 KT LOW LEVEL JET IS EXTENDING INTO WESTERN IOWA AND IS CURRENTLY
THE FOCUS FOR CONVECTION OFF TO OUR WEST. STORM MOTIONS ARE EXPECTED
TO BE SLIGHTLY NORTH OF EAST OVERNIGHT...AND THE JET IS EXPECTED TO
PROPAGATE NORTHEAST INTO SOUTHERN WISCONSIN IN THE PREDAWN HOURS.
CONSIDERING THESE FACTORS...IT SEEMS INCREASINGLY UNLIKELY THAT
THUNDERSTORMS WILL DEVELOP IN A FAVORABLE POSITION TO MOVE ACROSS
THE ROCKFORD/CHICAGO TERMINALS. THAT SAID...WITH BROAD ASCENT FROM
WARM ADVECTION ACROSS THE AREA...CANNOT RULE OUT SOMETHING ISOLATED
DEVELOPING CLOSER TO THE TERMINALS TONIGHT. GIVEN THE LOW
PROBABILITY OF THIS OCCURRING AND THE LIKELY ISOLATED NATURE IF IT
DOES OCCUR...WILL PULL MENTION OF THUNDER FROM THE TAFS FOR THE
REMAINDER OF THE OVERNIGHT HOURS.

MAIN CONCERN DURING THE DAY TUESDAY WILL BE WINDS. DEEP MIXING IS
EXPECTED TO OCCUR WHICH SHOULD HELP BRING DOWN WINDS IN THE MID TO
UPPER 20 KT RANGE...POSSIBLY EVEN 30 KTS AT TIMES. WIND SHOULD
PRIMARILY BE IN THE 190-210 DIRECTION TOMORROW DURING THE DAY.

BMD

//ORD AND MDW CONFIDENCE...UPDATED 06Z...

* LOW CONFIDENCE IN TSRA/SHRA IMPACTING THE TERMINALS
  TONIGHT...MEDIUM CONFIDENCE IN DRY FORECAST.
* HIGH CONFIDENCE IN WINDS 170-210 THROUGH PERIOD...MEDIUM
  CONFIDENCE IN WIND SPEEDS.
* HIGH CONFIDENCE IN VFR CONDITIONS THROUGH PERIOD.

BMD

//OUTLOOK FOR ORD/MDW FOR 12Z WEDNESDAY-12Z MONDAY...UPDATED 00Z...

WEDNESDAY...LOW SHRA/TSRA CHANCES INCREASE LATE.

THURSDAY...CHANCE SHRA/TSRA. MVFR POSSIBLE.

FRIDAY...SHRA LIKELY. MVFR LIKELY.

SATURDAY...CHANCE SHRA. MVFR POSSIBLE.

SUNDAY...SLIGHT CHANCE SHRA.

MDB

&&

.MARINE...
251 AM CDT

INCREASING SOUTHERLY FLOW TO AROUND 30 KT IS EXPECTED ACROSS LAKE
MICHIGAN TODAY AS DEEP AREA OF LOW PRESSURE OVER SOUTH DAKOTA EARLY
THIS MORNING LIFTS NORTHEAST INTO CANADA. A SMALL CRAFT ADVISORY
WILL BE HOISTED THIS MORNING AS WINDS ARE ALREADY GUSTING INTO THE
LOW 20 KT RANGE OVERNIGHT. MOIST ADVECTION OF MID TO UPPER 50
DEWPOINT AIR OVER THE LAKE WILL KEEP THE THREAT FOR FOG OVER THE
LAKE THROUGH THE DAY TODAY. STRONG HIGH PRESSURE BUILDS ACROSS THE
CANADIAN PRAIRIES...WHILE THE COLD FRONT EXTENDING SOUTH FROM THE
LOW MOVING OVER HUDSON BAY WILL GRADUALLY PUSH SOUTH ACROSS LAKE
MICHIGAN. EXPECT STRONG SOUTHERLY FLOW AHEAD OF THE FRONT TO
BECOME STRONG NIGHTLY BEHIND THE FRONT...AGAIN TO AROUND 30 KT.
TIMING AND SPEED OF THE FRONTAL PASSAGE CONTINUES TO REMAIN
UNCERTAIN HOWEVER.

BMD

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&

$$

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AREA FORECAST DISCUSSION

NWS CHICAGO/ROMEOVILLE IL

 1230 AM CDT TUE APR 30 2013

.DISCUSSION...

939 PM...EVENING UPDATE...CONVECTIVE TRENDS OVERNIGHT REMAIN
UNCERTAIN. MASSIVE STORM DEVELOPED SOUTHWEST OF DBQ 1-2 HOURS AGO
PRODUCING UP TO TENNIS BALL SIZED HAIL. THIS STORM HAS SINCE
WEAKENED AS IT MOVES INTO SOUTHWEST WI. ADDITIONAL ACTIVITY ALSO
BUBBLING ACROSS CENTRAL IA AND SHORT TERM/HIGH RES GUIDANCE SEEMS
TO FOCUS ON THIS AREA FOR FURTHER DEVELOPMENT LATE THIS EVENING AS
THE LOW LEVEL JET DEVELOPS/INCREASES...WITH THIS ACTIVITY LIFTING
NORTH INTO SOUTH/CENTRAL WI OVERNIGHT. AT THE SAME TIME...DECENT
AGREEMENT FOR ADDITIONAL DEVELOPMENT OVER LAKE MICHIGAN WHICH
DEVELOPS SOUTHEAST INTO NORTHWEST INDIANA IN THE PREDAWN HOURS
TOWARD SUNRISE. WITH EITHER OF THESE SCENARIOS PLAUSIBLE...ITS
POSSIBLE THAT MUCH OF THE CWA COULD REMAIN DRY OVERNIGHT AND INTO
TUESDAY MORNING. BUT ISOLATED ACTIVITY CURRENTLY DEVELOPING
SOUTHEAST OF DBQ WHICH WILL NEED TO BE MONITORED IN THE SHORT
TERM. THUS GIVEN LOW CONFIDENCE...HAVE MAINTAINED LOW CHANCE POPS
FOR AREAS GENERALLY ALONG/NORTH OF THE I-80 CORRIDOR BUT HAVE
INCLUDED SOME TIMING/TRENDS IN THE GRIDS...ALL OF WHICH WILL
LIKELY NEED ADJUSTMENTS THROUGH THE NIGHT. ANY ORGANIZED CELLS
THAT DEVELOP WILL HAVE THE POTENTIAL TO PRODUCE LARGE HAIL. CMS

//PREV DISCUSSION...
323 PM CDT

MAIN FORECAST CONCERNS ARE TRYING TO TIME PERIODS OF PRECIP
POTENTIAL THROUGH MID-WEEK...AND WARM TEMPS DURING THE SAME TIME
PERIOD. BEYOND MID-WEEK...CLOSED UPPER LOW LOOKS TO INFLUENCE LOCAL
WEATHER FOR SEVERAL DAYS WITH COOLER TEMPS AND PERSISTENT THREAT OF
SCATTERED SHRA/TSRA.

NEAR TERM...TONIGHT-WEDNESDAY

SMALL CLUSTER OF ISOLATED SHRA/TSRA CONTINUES TO PROPAGATE EAST
ALONG THE IL/WI BORDER THIS AFTERNOON...ON NOSE OF 25-30 KT LOW
LEVEL JET PER LOCAL VWP AND ASSOCIATED WARM/MOIST ADVECTION. HAS NOT
BEEN MUCH REDEVELOPMENT UPSTREAM OF THIS CLUSTER...THOUGH IT HAS
BEEN QUITE PERSISTENT IN MAINTAINING AT LEAST ONE FAIRLY STRONG TSRA
CORE FOR SEVERAL HOURS. EXPECT THIS WILL CONTINUE TO MOVE EAST
ACROSS BOONE/MCHENRY AND LAKE COUNTIES OVER THE NEXT COUPLE OF HOURS
AND MAY PRODUCE SOME ISOLATED NICKEL-QUARTER SIZED HAIL SOUTH OF THE
WI STATE LINE. LOOKING AT THE BIGGER PICTURE...GOES VAPOR IMAGERY
DEPICTS ONE MID-LEVEL SHORT WAVE MOVING ACROSS WI/NORTHERN GREAT
LAKES REGION THIS AFTERNOON...WITH ANOTHER UPSTREAM ACROSS KS/NEBR.
IT WOULD APPEAR THAT THERE WOULD BE A LULL IN PRECIP DEVELOPMENT
BETWEEN THESE TWO FORCING MECHANISMS THIS EVENING...WITH THE PLAINS
WAVE APPROACHING THE AREA LATE TONIGHT. HOWEVER...SEVERAL HIGH-RES
CONVECTION-ALLOWING MODELS INDICATE POTENTIAL REDEVELOPMENT OF
SHRA/TSRA ACROSS EASTERN IA INTO NORTHERN IL THIS EVENING...WHERE
WEAK LOW LEVEL JET AND MOIST/INSTABILITY AXIS LINGER. MID-AFTERNOON
VISIBLE SATELLITE IMAGERY DOES INDICATE SOME CU ATTEMPTING TO FORM
ACROSS SOUTHEAST IA WITHIN SFC MOIST AXIS...THOUGH IT IS NOT TOO
IMPRESSIVE AT THIS TIME. SPC RAP MESOANALYSIS DATA DOES DEPICT AN
AXIS OF 1000-2000 J/KG MLCAPE ACROSS SE IA...THOUGH ALSO INDICATES
SOME 75-100 J/KG OF CIN. BASED ON PRESENCE OF MOIST/UNSTABLE AXIS
AND HIGH-RES GUIDANCE TRENDS OF REDEVELOPMENT HAVE CHOSEN TO
MAINTAIN CHANCE POPS FOR SHRA/TSRA ACROSS MAINLY AREAS NORTH OF I-80
THROUGH TONIGHT...ESPECIALLY WEST THIS EVENING AND SPREADING FARTHER
EAST LATER TONIGHT. LACK OF STRONGER SHORT WAVE FORCING KEEPS
CONFIDENCE ON THE LOW SIDE THIS EVENING HOWEVER...WITH A LITTLE
HIGHER CONFIDENCE OVERNIGHT AS PLAINS SHORT WAVE APPROACHES AND
PASSES ACROSS THE AREA EARLY TUESDAY MORNING.

ON TUESDAY...ONCE MORNING SHORT WAVE PASSES IT APPEARS FORCING FOR
ORGANIZED PRECIP WILL BE LACKING. COLD FRONT TO OUR WEST IS NOT
EXPECTED TO MAKE PROGRESS EAST AS UPPER FLOW AMPLIFIES IN RESPONSE
TO STRONG MID/UPPER LEVEL JET MOVING INTO THE PAC NW. THIS
AMPLIFICATION INDUCES SURFACE LOW PRESSURE DEVELOPING AND LIFTING
NORTHEAST INTO ONTARIO. THIS ALLOWS STRONGER LOW LEVEL SOUTH FLOW
ACROSS IL/IN...WITH WARMER TEMPS. COMBINATION OF LOW LEVEL THERMAL
PROGS...850 MB DERIVED TEMP CLIMATOLOGY AND MOS NUMBERS SUGGEST
AFTERNOON HIGHS 80-85...PROVIDED MORNING CLOUD COVER MOVES OUT AS
EXPECTED. 850 MB TEMPS JUST A BIT LOWER WEDNESDAY AS UPPER TROUGH
CONTINUES TO AMPLIFY AND SURFACE COLD FRONTAL TROUGH DRIFTS EAST
INTO THE REGION...THOUGH ESPECIALLY EASTERN AREAS WILL LIKELY BE
BACK INTO THE LOWER 80S WHILE CLOUDS/PRECIP CHANCES INCREASE FROM
THE WEST. VARIOUS GUIDANCE SOLUTIONS SHOW SOME MINOR DIFFERENCES
WITH TIMING OF ARRIVAL OF THE FRONT AND ASSOCIATED PRECIP...THOUGH
ALL BASICALLY INCREASE POPS FAIRLY QUICKLY ACROSS THE CWA WEDNESDAY
NIGHT.

LONGER TERM...THURSDAY-MONDAY

MODELS CONTINUE THE TREND OF THE AMPLIFYING UPPER TROUGH BECOMING
CUT OFF FROM THE MAIN JET AND BECOMING A CLOSED LOW OVER THE
MID/LOWER MISSOURI VALLEY...THEN DRIFTING THIS CIRCULATION TO THE
EAST/NORTHEAST THROUGH THE REMAINDER OF THE FORECAST PERIOD. QUITE A
BIT OF SPREAD REMAINS IN ENSEMBLE SOLUTIONS...AS WELL AS THE
OPERATIONAL RUNS OF THE ECMWF/GFS. HAVE MADE LITTLE CHANGE TO GOING
FORECAST IN THE EXTENDED PERIOD AT THIS POINT BASED ON FAIRLY LOW
CONFIDENCE GIVEN MODEL SPREAD...AND THE NOTORIOUSLY PROBLEMATIC JOB
OF FORECASTING CUT-OFF CLOSED LOW DETAILS DAYS 4 AND BEYOND. OVERALL
HAVE MAINTAINED A FORECAST UTILIZING A BLEND OF GUIDANCE FOR TEMPS
AND POPS. WHILE COOLER...LOOKS LIKE 50S/60S FOR HIGHS AND 40S FOR
LOWS DEPENDING ON CLOUD COVER AND SHOWER COVERAGE. POPS ARE LIKELY
OVERDONE A BIT...AND WILL LIKELY BE ABLE TO BETTER DETAIL THEM IN
COMING DAYS AS THE PATH OF THE UPPER LOW BECOMES MORE CLEAR.

RATZER

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 06Z...

* LOW CHANCES FOR SHRA/TSRA OVERNIGHT.
* GUSTY SOUTHERLY WINDS AROUND 25KT OR SO TUESDAY AFTERNOON.

BMD

//DISCUSSION...UPDATED 06Z...

LOW PRESSURE LIES OVER THE DAKOTAS THIS EVENING WITH SOUTHERLY FLOW
IN PLACE ACROSS NORTHERN ILLINOIS. MODERATE INSTABILITY LIES OVER
THE AREA THIS EVENING HOWEVER THE BEST FOCUS FOR FORCING IS EXPECTED
TO REMAIN WEST AND NORTHWEST OF THE TERMINALS THROUGH THE NIGHT. A
60 KT LOW LEVEL JET IS EXTENDING INTO WESTERN IOWA AND IS CURRENTLY
THE FOCUS FOR CONVECTION OFF TO OUR WEST. STORM MOTIONS ARE EXPECTED
TO BE SLIGHTLY NORTH OF EAST OVERNIGHT...AND THE JET IS EXPECTED TO
PROPAGATE NORTHEAST INTO SOUTHERN WISCONSIN IN THE PREDAWN HOURS.
CONSIDERING THESE FACTORS...IT SEEMS INCREASINGLY UNLIKELY THAT
THUNDERSTORMS WILL DEVELOP IN A FAVORABLE POSITION TO MOVE ACROSS
THE ROCKFORD/CHICAGO TERMINALS. THAT SAID...WITH BROAD ASCENT FROM
WARM ADVECTION ACROSS THE AREA...CANNOT RULE OUT SOMETHING ISOLATED
DEVELOPING CLOSER TO THE TERMINALS TONIGHT. GIVEN THE LOW
PROBABILITY OF THIS OCCURRING AND THE LIKELY ISOLATED NATURE IF IT
DOES OCCUR...WILL PULL MENTION OF THUNDER FROM THE TAFS FOR THE
REMAINDER OF THE OVERNIGHT HOURS.

MAIN CONCERN DURING THE DAY TUESDAY WILL BE WINDS. DEEP MIXING IS
EXPECTED TO OCCUR WHICH SHOULD HELP BRING DOWN WINDS IN THE MID TO
UPPER 20 KT RANGE...POSSIBLY EVEN 30 KTS AT TIMES. WIND SHOULD
PRIMARILY BE IN THE 190-210 DIRECTION TOMORROW DURING THE DAY.

BMD


//ORD AND MDW CONFIDENCE...UPDATED 06Z...

* LOW CONFIDENCE IN TSRA/SHRA IMPACTING THE TERMINALS
  TONIGHT...MEDIUM CONFIDENCE IN DRY FORECAST.
* HIGH CONFIDENCE IN WINDS 170-210 THROUGH PERIOD...MEDIUM
  CONFIDENCE IN WIND SPEEDS.
* HIGH CONFIDENCE IN VFR CONDITIONS THROUGH PERIOD.

BMD

//OUTLOOK FOR ORD/MDW FOR 12Z WEDNESDAY-12Z MONDAY...UPDATED 00Z...

WEDNESDAY...LOW SHRA/TSRA CHANCES INCREASE LATE.

THURSDAY...CHANCE SHRA/TSRA. MVFR POSSIBLE.

FRIDAY...SHRA LIKELY. MVFR LIKELY.

SATURDAY...CHANCE SHRA. MVFR POSSIBLE.

SUNDAY...SLIGHT CHANCE SHRA.

MDB

&&

.MARINE...
205 PM CDT

A POTENT AREA OF LOW PRESSURE IS FORECAST MOVE EASTWARD ACROSS THE
DAKOTAS TONIGHT...AND THEN MOVE NORTHEASTWARD ACROSS ONTARIO ON
TUESDAY. STRONG PRESSURE FALLS AND A STRENGTHENING PRESSURE GRADIENT
SHOULD LEAD TO A PERIOD OF STRONGER SOUTHERLY WINDS ACROSS THE LAKE
ON TUESDAY. IT APPEARS WINDS WILL INCREASE TO AROUND 30 KT
LAKE-WIDE.

THIS LOW WILL EVENTUALLY BEGIN TO PUSH A COLD FRONT DOWN LAKE
MICHIGAN DURING THE DAY ON WEDNESDAY. HOWEVER...CONFIDENCE ON THE
TIMING OF THIS FRONT IS A BIT LOW AT THIS TIME..ESPECIALLY ALONG
THE SOUTHERN HALF OF LAKE MICHIGAN. IT APPEARS THE FRONT  MAY BE
SLOWED BY THE DEVELOPMENT OF ANOTHER AREA OF LOW PRESSURE ACROSS THE
MID MISSISSIPPI VALLEY. THIS WILL ULTIMATELY AFFECT THE WIND
DIRECTIONS ON SOUTHERN LAKE MICHIGAN LATER THIS WEEK. NORTHERLY
WINDS OF 25 TO 30 KT LOOK TO SET UP FOR A PERIOD IN THE WAKE OF THIS
FRONTAL BOUNDARY ON THURSDAY.

KJB

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&

$$

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AREA FORECAST DISCUSSION

NWS INDIANAPOLIS IN

 1218 AM EDT TUE APR 30 2013

.UPDATE...
AVIATION SECTION HAS BEEN UPDATED BELOW

&&

.SYNOPSIS...
ISSUED AT 315 PM EDT MON APR 29 2013

A DRY AND WARM WEATHER PATTERN HAS BEGUN ACROSS CENTRAL INDIANA
THIS AFTERNOON AND WILL PERSIST THROUGH MID-WEEK. THAT IS WHEN A
BROAD UPPER LEVEL CUTOFF LOW WILL BECOME ANCHORED OVER MUCH OF THE
REGION BRINGING SCATTERED SHOWERS AND THUNDERSTORMS ON THURSDAY
AND FRIDAY. THUNDERSTORM POTENTIAL WILL COME TO AN END BY FRIDAY
NIGHT...BUT RAIN SHOWERS WILL CONTINUE INTO MONDAY AS THE
AFOREMENTIONED UPPER LOW TRACKS ACROSS THE MID-ATLANTIC.

&&

.NEAR TERM /REST OF TONIGHT/...

ISSUED AT 946 PM EDT MON APR 29 2013

FORECAST IS RUNNING ON TRACK AS MID AND HIGH CLOUDS ARE MOVING
INTO THE NORTHERN AND CENTRAL COUNTIES FROM DEVELOPMENT ACROSS
NORTHERN ILLINOIS AND IOWA. HRRR AND RAP STILL KEEP ALL CONVECTION
WELL TO THE NORTH. GOING LOWS IN THE LOW TO MID 50S LOOK GOOD. A
LITTLE CONCERN THAT PATCHY FOG COULD DEVELOP IN THE SOUTHEAST
WHERE CLOUDS WERE LATE TO LEAVE AND WILL BE LATE TO ARRIVE AND
WINDS SHOULD BE A LITTLE LIGHTER...BUT SOUNDINGS DON/T LOOK TOO
FAVORABLE AND DEW POINT DEPRESSIONS ARE STILL PRETTY LARGE. THUS
THOUGHT CHANCE FOR FOG IS STILL LOW ENOUGH AT THIS TIME TO LEAVE
OUT OF FORECAST.

&&

.SHORT TERM /TOMORROW THROUGH THURSDAY/...

ISSUED AT 315 PM EDT MON APR 29 2013

THE FOCUS OF THE SHORT TERM PERIOD IS THE APPROACHING UPPER LEVEL
CUTOFF LOW.

MODELS CONTINUE TO TREND TOWARD A DRY FORECAST THROUGH WEDNESDAY
AS A RIDGE OF HIGH PRESSURE SETS UP OVER THE OHIO VALLEY AND
NORTHEAST. THIS RIDGE WILL BLOCK THE UPPER LEVEL LOW FROM
ENTERING CENTRAL INDIANA UNTIL THURSDAY. FOR NOW...HAVE SLIGHT
CHANCE POPS OVER THE EASTERN COUNTIES AND CHANCE POPS ELSEWHERE
STARTING THURSDAY MORNING. HOWEVER...WOULD NOT BE SURPRISED IF
TIMING OF PRECIP ONSET GETS PUSHED BACK FURTHER.

TEMPS...TRENDED TOWARD THE WARMER GFS FOR TOMORROW...BUT BY
WEDNESDAY...THE NAM FINALLY STARTS PICKING UP ON THE WARMING
TREND. AS A RESULT...WAS ABLE TO GO WITH A MAVMOS BLEND LATE IN
THE SHORT TERM PERIOD. THIS PUTS HIGHS IN THE LOW 80S AND
OVERNIGHT LOWS GENERALLY IN THE UPPER 50S.

&&

.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...

ISSUED AT 255 PM EDT MON APR 29 2013

FOCUS FOR THE EXTENDED REMAINS ON THE EXPECTED DEVELOPMENT OF A
LARGE AND UNUSUALLY STRONG CUTOFF UPPER LOW FOR EARLY MAY ACROSS THE
MIDWEST AND POTENTIAL IMPACTS TO CENTRAL INDIANA. MODELS ARE IN
BETTER AGREEMENT TODAY WITH INITIALLY CUTTING OFF THE UPPER LOW OVER
THE CENTRAL PLAINS ON FRIDAY AS THE BROAD POLAR TROUGH AMPLIFIES.
WHERE THE SYSTEM GOES AFTER THAT THOUGH REMAINS A BIG MYSTERY AND
HINGES TO SOME DEGREE ON POTENTIAL INTERACTION AND PHASING WITH AN
UPPER LOW ALONG THE GULF COAST.

12Z OP GFS CONTINUES TO WAFFLE ON ITS TRACK AND HAS COME IN MUCH
FURTHER SOUTH/EAST WITH THE PROGRESSION OF THE UPPER LOW THROUGH THE
EXTENDED PUTTING IT IN THE CENTRAL APPALACHIANS BY MONDAY NIGHT. 12Z
GGEM OUT INTO THE WEEKEND ALSO APPEARS TO BE TRENDING IN THE
DIRECTION OF THE GFS TRACK. CLOSER ANALYSIS SHOWING THAT BOTH OF
THESE MODELS ARE DEPICTING A STRONGER/SLOWER UPPER LOW ALONG THE
GULF COAST AND CONSEQUENTLY GREATER INTERACTION BETWEEN THE TWO
FEATURES. 12Z ECMWF IS SUPPORTED BY THE UKMET...MAINTAINING A
NORTHERLY TRACK TO THE UPPER LOW INTO THE NORTHERN GREAT LAKES BY
MONDAY BEFORE BECOMING ABSORBED BY A DEEPENING TROUGH OVER WESTERN
CANADA. 12Z GFS ENSEMBLES ONCE AGAIN PROVIDE NO HELP TODAY...
INDICATING WIDE VARIANCE ON THE UPPER LOW TRACK BETWEEN ITS MEMBERS
OVER THE WEEKEND.

CONTINUE TO FAVOR A TRACK CLOSER TO THE ECMWF SOLUTION PARTLY
BECAUSE IT HAS BEEN FAR AND AWAY THE MOST CONSISTENT MODEL WITH
RESPECT TO THE UPPER LOW OVER THE LAST FEW DAYS...AND BECAUSE THE OP
GFS/GGEM TRACK ACROSS THE SOUTHEAST STATES IS HIGHLY UNUSUAL. EVEN
WITH GREATER INTERACTION WITH THE UPPER WAVE ALONG THE GULF
COAST...DO NOT ANTICIPATE THE PARENT UPPER LOW TO BE PULLED THAT FAR
S/E. HAVE DEVIATED LITTLE FROM ALLBLEND WITH SUCH LOW CONFIDENCE ON
THE UPPER LOW TRACK AT THIS POINT...AND WILL CONTINUE TO CARRY POPS
THROUGH THE ENTIRE EXTENDED. HIGHEST CONFIDENCE IN WIDESPREAD
RAINFALL REMAINS ON FRIDAY/SATURDAY WITH LOWER POPS BEYOND THAT.
WILL KEEP HIGHS MAINLY IN THE 60S THROUGH THE PERIOD WITH
EXPECTATION THAT UPPER LOW REMAINS TO THE NORTHWEST OF REGION.
SHOULD A TRACK FURTHER SOUTH INTO THE OHIO VALLEY COME TO
FRUITION...TEMPS WOULD NEED TO BE LOWERED AND POPS RAISED.

&&

AVIATION /DISCUSSION FOR 300600Z TAF ISSUANCE/...
ISSUED AT 1218 AM EDT TUE APR 30 2013

VFR THROUGH THE PERIOD WITH THE POSSIBLE EXCEPTION OF KBMG WHERE A
PERIOD OF MVFR FOG EARLY THIS MORNING STILL POSSIBLE.

HIGH PRESSURE ALONG THE EAST COAST AND AN LOW PRESSURE MOVING INTO
THE CENTRAL PLAINS WILL KEEP A MODERATE SOUTHERLY FLOW ACROSS OUR
REGION.  SCATTERED THUNDERSTORMS MAY TRACK ACROSS NORTHERN ILLINOIS
INTO THE SOUTHERN GREAT LAKES OVERNIGHT AND SOME HIGH CLOUDINESS
FROM THIS MAY SPREAD INTO OUR NORTHERN AREAS.

HAVE BACKED OFF A LITTLE MORE ON THE FOG POTENTIAL AS THERE IS STILL
A PRETTY GOOD PRESSURE GRADIENT AND DEWPOINTS DEPRESSIONS ARE STILL
RUNNING 6 DEGREES OR MORE.  THE WIND AT KBMG MAY BE LESS...SO WILL
CONTINUE A TEMPO 4 MILES THERE.

OTHERWISE...LOOK FOR SCATTERED CU TO BE THE RULE WITH BROKEN TO
SCATTERED HIGH CLOUDS ON TUESDAY AND BECOMING MOSTLY CLEAR
TUESDAY NIGHT.

SOUTH WINDS WILL BE 8 KNOTS OR LESS THROUGH EARLY MORNING AND THEN
UP TO 12 KNOTS TUESDAY BEFORE DIMINISHING TUESDAY EVENING.

&&

.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SYNOPSIS...TDUD
NEAR TERM...CP
SHORT TERM...TDUD
LONG TERM....RYAN
AVIATION...JH















AREA FORECAST DISCUSSION

NWS DES MOINES IA

 1228 AM CDT TUE APR 30 2013

.SHORT TERM.../TONIGHT /...
ISSUED AT 338 PM CDT MON APR 29 2013

MAIN CONCERN FOR THE OVERNIGHT PERIOD WILL BE THE TIMING AND
LOCATION OF ANY CONVECTION. INSTABILITY HAS BEEN ON THE INCREASE
THIS AFTERNOON WITH SBCAPES OF 1000 TO 2000 J/KG ACROSS MUCH OF THE
CWA...AND EVEN HIGHER VALUES AROUND THE MISSOURI BORDER. THE 850 TO
700 MB CAP LOOKS TO WEAKEN AFTER THE 23-00Z TIME FRAME AS A 925MB
MOISTURE PLUME OVER KANSAS AND MISSOURI WORKS NORTHWARD. EXPECTING
CONVECTIVE INITIATION IN THE VICINITY OF THE ASSOCIATED THETA-E
CONVERGENCE ZONE IN SOUTHWEST IOWA OR SOUTHEAST NEBRASKA...WITH THE
CONVECTION TRACKING EAST AND NORTH DURING THE OVERNIGHT. THIRTY TO
FORTY KNOTS OF 0-6 KM SHEAR AND A 40 TO 60 KT LLJ BUILDING IN FROM
THE SOUTHWEST AFTER 03Z WILL AID IN INTENSIFYING AND MAINTAINING ANY
STORMS THAT DO FORM THIS EVENING. BOTH ELEVATED AND SURFACE BASED
CONVECTION IS POSSIBLE WITH THE MAIN THREAT FROM THESE STORMS BEING
LARGE HAIL AND DAMAGING WIND GUSTS.

MANY HIGH RESOLUTION MODELS HAVE BEEN TRENDING THE CONVECTION
SLIGHTLY NORTH AND WEST TODAY. THIS HAS ALSO BEEN REFLECTED IN THE
UPDATED SPC CONVECTIVE DAY 1 SLIGHT RISK OUTLOOKS. IN
GENERAL...LEANED TOWARDS A COMBINATION OF THE EAST NMM AND ARW WRF
CORES AND THE 16Z HRRR FOR PLACEMENT OF THE HIGHEST POPS AND QPF
AMOUNTS. HEAVY RAINFALL IS POSSIBLE WITH SOME OF THESE STORMS OVER
CENTRAL IOWA WITH PWATS EXCEEDING ONE INCH AND LOW LEVEL MIXING
RATIOS AROUND 13 G/KG.

STATIONARY SURFACE BOUNDARY OVER WEST CENTRAL AND NORTH CENTRAL IOWA
WASHED OUT EARLY THIS AFTERNOON...ALLOWING WINDS TO VEER SOUTHWARD
AND TEMPERATURES TO RISE BACK INTO THE 70S. THESE SOUTHERLY WINDS
WILL INCREASE OVERNIGHT AS THE PRESSURE GRADIENT TIGHTENS IN RESPONSE
TO AN APPROACHING NORTHERN PLAINS COLD FRONT. COMBINED WITH DEW POINTS IN
THE UPPER 50S TO NEAR 60...EXPECT OVERNIGHT LOWS TO ONLY FALL OFF
INTO THE LOW 60S.

.LONG TERM.../TUESDAY THROUGH MONDAY/...
ISSUED AT 338 PM CDT MON APR 29 2013

I EXPECT SOME ONGOING CONVECTION MAINLY ACROSS THE EAST IN THE
MORNING WITH A LULL LATE MORNING.  ANOTHER COLD FRONT WILL STRETCH
ACROSS CENTRAL IOWA DURING THE DAY ON TUESDAY AND MAKE SLOW ESE
PROGRESS.  FORECAST SOUNDINGS SHOW A PRETTY STOUT CAP IN PLACE BUT
IT QUICKLY ERODES DURING THE MID TO LATE AFTERNOON AND INTO THE
EVENING AND THIS IS WHEN I EXPECT THUNDERSTORMS TO BREAK OUT...AHEAD
OF THE BOUNDARY.  LOOKING AT SHEAR...THERE IS SOME THAT EXISTS ALONG
THE BOUNDARY BUT THE BEST SHEAR IS FOUND BEHIND THE BOUNDARY.  SOME
STORMS COULD PRODUCE LARGE HAIL AND DAMAGING WIND.  DURING TUESDAY
EVENING ADDITIONAL STORMS COULD DEVELOP BEHIND THE FRONT AS WELL
WHERE THE BETTER SHEAR WILL EXIST AND THERE WILL STILL BE SOME
INSTABILITY.

ON WEDNESDAY THE UPPER TROUGH OUT TO THE WEST WILL DIG SOUTH ON THE
LEE SIDE OF THE ROCKIES CREATING QUITE THE TEMPERATURE GRADIENT
ACROSS IOWA.  ACROSS THE NORTHWEST HALF TO TWO THIRDS OF THE STATE
HIGHS WILL ONLY BE IN THE 40S AND 50S WHILE ACROSS THE SOUTHEAST
TEMPERATURES WILL BE IN THE 60S TO 70S.  THIS TROUGH WILL CONTINUE
TO DIG AS IT PLOWS EAST THROUGH THURSDAY.  FORECAST SOUNDINGS ON
THURSDAY SHOW FALLING TEMPERATURES THROUGHOUT THE AFTERNOON HOURS.
IN FACT IT LOOKS LIKE HIGHS WILL LIKELY BE REACHED IN THE MORNING
AND THOSE READINGS WILL ONLY BE IN THE 40S.  PRETTY DECENT MOISTURE
TRANSPORT WILL TAKE PLACE DURING THIS TIME AND PRECIPITATION WILL
YIELD SOME PRETTY HIGH QPF VALUES THROUGH THE REMAINDER OF THE
WEEK.  FORECAST SOUNDINGS SHOW THAT WE WILL BE COLD ENOUGH FOR AT
MINIMUM A RAIN/SNOW MIX DURING THE DAY ON THURSDAY.  IF YOU BELIEVE
THE NAM WE WILL BE COLD ENOUGH FOR ALL SNOW.  I HAD A HARD TIME
BUYING INTO THAT SOLUTION COMPLETELY BECAUSE FOR THE PAST FEW DAYS
THE NAM HAD BEEN OVERDOING THE MOISTURE AND THE COOLING.  THIS WILL
CERTAINLY BEAR WATCHING BUT I WOULD NOT BE SURPRISED TO SEE SNOW
THURSDAY AFTERNOON AND THURSDAY NIGHT.

BEYOND THIS PERIOD...THE MODELS CONTINUE TO POORLY HANDLE THE
EVOLUTION OF THE CLOSED LOW THAT DEVELOPS OUT OF THE TROUGH.  THE
EURO LIFTS THIS CLOSED LOW INTO IOWA OVER THE WEEKEND THEN INTO THE
GREAT LAKES ON MONDAY WHILE THE GFS AND GEM TAKE THE LOW TO THE
SOUTH ACROSS THE SOUTHERN PLAINS.  THIS SOLUTION WOULD DRAW DOWN
MUCH COLDER AIR ACROSS THE STATE FOR THE WEEKEND.  I TRIED TO LEAN
COOLER BUT BY SUNDAY FORECAST SOUNDINGS SUPPORT HIGHS IN THE 50S. AT
THIS POINT I KEPT 40S NW TO 50S SE ON SATURDAY BUT WE COULD INDEED
SEE TEMPS SOME 5 TO 8 DEGREES COOLER THAT WHAT I HAVE GOING.  WE
WILL NEED TO SEE HOW THAT CLOSED LOW EVOLVES AND SHIFTS ACROSS THE
AREA.  BEFORE THAT HAPPENS THERE IS JUST TOO MUCH MODEL UNCERTAINTY
TO STATE A PREFERENCE.

&&

.AVIATION...30/06Z
ISSUED AT 1224 AM CDT TUE APR 30 2013

BAND OF SHOWERS AND THUNDERSTORMS WILL PUSH NE ACROSS THROUGH 12Z
AFFECTING NORTHERN SITES KFOD/KALO/KMCW. CEILINGS MAY DROP AT TIMES
TO MVFR IN THUNDERSTORMS AND WINDS WILL BE GUSTY. BEHIND STORMS
WINDS WILL BE FROM THE SOUTH AND CEILINGS WILL BE VFR. WINDS WILL
INCREASE IN THE DAY TUESDAY WITH APPROACHING FRONTAL BOUNDARY. MAY
SEE ADDITIONAL THUNDERSTORMS LATE IN AFTERNOON...BUT DO NOT HAVE
ENOUGH CONFIDENCE IN COVERAGE TO INCLUDE MENTION AT SITES ATTM.
BEHIND BOUNDARY WINDS WILL SHIFT TO THE NORTH LATE IN THE PERIOD.

&&

.HYDROLOGY...
ISSUED AT 338 PM CDT MON APR 29 2013

HE MODERATE TO HEAVY RAINFALL EVENT FORECAST IN THE LONG TERM
PERIOD OF THE FORECAST MAY RESULT IN SIGNIFICANT WITHIN-BANK RISES
ALONG MANY STREAMS AND RIVERS. FLOODING IS ALSO
POSSIBLE...ESPECIALLY ALONG THE SMALLER STREAMS AND IN AREAS THAT
RECEIVE HEAVIER RAINFALL. AT THIS TIME IT IS DIFFICULT TO PINPOINT
SPECIFIC STREAMS OR RIVERS GIVEN THE UNCERTAINTY IN THE RAINFALL
FORECAST. THE FORECAST WILL HAVE TO BE MONITORED FOR POTENTIAL
IMPACTS ON AREA RIVERS.

&&

.DMX WATCHES/WARNINGS/ADVISORIES...NONE.

&&

$$

SHORT TERM...SKOW
LONG TERM...FAB
AVIATION...AWB
HYDROLOGY...ZOGG







AREA FORECAST DISCUSSION

NWS MARQUETTE MI

 545 AM EDT TUE APR 30 2013

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 516 AM EDT TUE APR 30 2013

WV IMAGERY AND RUC ANALYSIS INDICATED A BROAD MID/UPPER LEVEL TROUGH
OVER THE NW CONUS RESULTING IN SW FLOW FROM THE CNTRL PLAINS TO THE
NRN GREAT LAKES. A VIGOROUS SHORTWAVE TROUGH WAS LCOATED OVER THE SE
CORNER OF SASK INTO FAR NW ND.  AT THE SFC...LOW PRES WAS LOCATED
OVER NE SOUTH DAKOTA WITH A WARM FRONT THROUGH SE MN INTO SRN WI. A
LLJ AHEAD OF THE WITH INFLOW OF MOIST/UNSTABLE AIR SUPPORTED TSRA
INTO SRN WI AND CNTRL LAKE MI. ISOLD SHOWERS NEAR ESC-ISQ HAD
DIMINISHED AS THE STRONGER CONVECTION DEVELOPED TO THE SOUTH.
UPSTREAM...A WEAK SHRTWV AHEAD OF THE LOW  SUPPORTED A BAND OF
SHRA/TSRA OVER NRN MN.

RADAR AND SATELLITE TRENDS SUGGEST THAT MOST OF THE CONVECTION OVER
WI WILL SLIDE JUST SOUTH OF THE CWA BUT MAY EXPAND JUST ENOUGH FOR
SOME SCT SHRA/TSRA...MAINLY SOUTH OF A LINE FROM IMT-ERY. AS THE SD
LOW LIFTS NORTHEAST THROUGH THROUGH NW MN TO NW ONTARIO...WAA AND
MOISTURE ADVECTION WILL INCREASE WITH THE STRENGTHENING SRLY FLOW.
TEMPS CLIMBING INTO THE LOWER TO MID 70S COMBINED WITH DEWPOINTS IN
THE LOWER TO MID 50S WILL RESULT IN MLCAPE VALUES IN THE 600-1200
J/KG RANGE BY THIS AFTERNOON. THE COLD FRONT DRAPED TO THE SOUTH OF
THE LOW MOVING INTO THE WEST UPPER MI THIS AFTERNOON WILL BE THE
MAIN FOCUS FOR SHRA/TSRA DEVELOPMENT. ALTHOUGH THE STRONGEST QVECTOR
CONV WILL BE WELL NORTH OF THE REGION...EVEN MODEST LOW LEVEL CONV
ALONG AND AHEAD OF THE FRONT SHOULD SUPPORT SCT TSRA THIS AFTERNOON
INTO THIS EVENING. SOME STRONGER STORMS MAY BE POSSIBLE WITH 0-6KM
SHEAR VALUES IN THE 40-50 KT...BUT THE GREATER SVR POTENTIAL IS
EXPECTED FARTHER SOUTH(PER SPC) WHERE INSTABILITY WILL BE GREATER.
THE HIGHEST POPS VALUES WERE INCLUDED OVER THE WEST LATE THIS
AFTERNOON AND INTO THE CNTRL AND EAST THIS EVENING...BEFORE
SHRA/TSRA WEAKEN WITH DIURNAL COOLING.

.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 442 AM EDT TUE APR 30 2013

NAM SHOWS A 500 MB RIDGE OVER THE EASTERN U.S. WITH A TROUGH IN THE
NORTHERN AND CENTRAL ROCKIES AND A CLOSED 500 MB LOW OVER THE GULF
COAST 12Z WED. THE TROUGH MOVES INTO THE NORTHERN PLAINS 00Z THU AND
INTO THE UPPER GREAT LAKES ON THU. NAM SHOWING SOME 850-500 MB
Q-VECTOR CONVERGENCE WITH DEEPER MOISTURE OVER THE WEST HALF OF
UPPER MICHIGAN 12Z WED WHICH REMAINS THROUGH 00Z THU. THIS NARROW
RIBBON OF DEEPER MOISTURE REMAINS OVER THE WESTERN CWA THROUGH 12Z
THU BEFORE THIS MOVES AND EXPANDS EASTWARD. GFS AND ECMWF SHOW ABOUT
THE SAME THING AS WELL.

THIS FORECAST PERIOD GETS DOMINATED BY COLDER AIR COMING INTO THE
AREA AND THERE COULD BE A RAIN/SNOW MIX ACROSS THE WESTERN U.P.
STARTING LATE WED NIGHT AND LASTING INTO THU NIGHT. THE WESTERN CWA
ALSO HAS THE BEST MOISTURE AND THEREFORE WILL HAVE THE HIGHEST POPS
WHILE THE EAST IS FURTHER AWAY FROM THE FRONTAL BAND PCPN THAT SETS
UP AND IS IN WARMER AIR AS WELL. QUITE A GRADIENT SETS UP IN
TEMPERATURES WITH THE COLDEST READINGS ACROSS THE WEST AND THE
WARMEST IN THE EAST FOR THROUGH THU. QPF WILL CONTINUE TO BE
HEAVIEST OVER THE WEST WITH ANYWHERE FROM 0.25 INCH ACROSS THE EAST
TO 1.25 IN THE WEST FROM WED TO THU NIGHT. THE COLD AIR DOES NOT
ARRIVE UNTIL LATE WED NIGHT ACROSS THE WEST AND COULD SEE ANYWHERE
FROM 1 TO 6 INCHES WEST OF A LINE FROM BIG BAY TO IRON RIVER FROM
WED NIGHT INTO THU NIGHT. DID RAISE TEMPERATURES A BIT FOR WED WITH
LATER ARRIVAL OF COLDER AIR AND RAISED THEM WED NIGHT AS WELL A
COUPLE DEGREES. OTHERWISE...DID NOT MAKE TOO MANY CHANGES TO THE
GOING FORECAST EXCEPT TO GO A BIT DRIER IN THE EASTERN CWA WHICH IS
FURTHER AWAY FROM THE FRONTAL BAND.

IN THE EXTENDED...GFS AND ECMWF SHOW A 500 MB TROUGH AND CLOSED LOW
OVER THE CENTRAL PLAINS 12Z FRI WITH A RIDGE OVER THE EASTERN U.S.
PATTERN DOES NOT CHANGE MUCH FOR 12Z SAT WITH THE 500 MB RIDGE
REMAINING STATIONARY. THIS 500 MB LOW CONTINUES TO SPIN ACROSS THE
CENTRAL PLAINS 12Z SUN FOR THE ECMWF AND THE GFS IS MUCH FURTHER
SOUTH WITH THE PLACEMENT OF THE 500 MB LOW. GFS CONTINUES TO MOVE
THE LOW EAST WELL SOUTH OF THE AREA 12Z MON WHILE THE ECMWF TAKES
THE LOW AND ASSOCIATED TROUGH THROUGH THE AREA. MANUAL PROGS KIND OF
WASH THIS SYSTEM OUT WITH TIME WITH WEAK SFC PRESSURE PATTERNS. WITH
SLOW CHANGE IN UPPER PATTERN...PERSISTENCE LOOKS TO BE THE WAY TO GO
FOR THIS FORECAST. TEMPERATURES WILL SLOWLY WARM THIS EXTENDED
FORECAST PERIOD FROM BELOW NORMAL TO NEAR NORMAL AND WILL BE WET
WITH PCPN CHANCES ALMOST EACH PERIOD.
&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 442 AM EDT TUE APR 30 2013

WITH THE ARRIVAL OF MOIST AIR FOG HAS DEVELOPED AT THE KCMX/KSAW
SITES....AND WITH GENERAL UPSLOPE FLOW IN THESE AREAS EXPECT THE
IFR/LIFR CONDITIONS TO CONTINUE THROUGH THE OVERNIGHT PERIOD.
DOWNSLOPING WINDS WILL LIKELY INHIBIT THE DEVELOPMENT OF ANY
SIGNIFICANT LOWER CEILINGS/VIS AT KIWD TONIGHT. A COLD FRONT WILL
CROSS UPPER MICHIGAN DURING THE DAYTIME TUESDAY...BRINGING SHOWERS
TO EACH OF THE TAF SITES...WITH KIWD/KCMX CLEARING OUT FOR THE LATE
AFTERNOON/EARLY EVENING TIME FRAME FOR A SHORT TIME. ISOLATED
THUNDERSTORMS ARE POSSIBLE TOMORROW...ESPECIALLY AT KSAW...BUT
CONFIDENCE WAS NOT HIGH ENOUGH TO INCLUDE IN THE TAF.
OTHERWISE...WITH THE APPROACHING FRONT AND
HEATING/MIXING...SOUTHERLY WINDS ARE EXPECTED TO BE GUSTING TO NEAR
25KTS TOWARDS THE AFTERNOON HOURS BEFORE SHIFTING TO THE WEST.
LASTLY...LLWS IS STILL POSSIBLE TONIGHT AT THE TAF SITES WITH
STRONGER SOUTHERLY WINDS ALOFT.
&&

.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 442 AM EDT TUE APR 30 2013

NO GALES SEEN IN THIS FORECAST PERIOD. WINDS DO GET UP TO 30 KNOTS
ACROSS THE EAST AND NORTH CENTRAL TODAY AS A SFC LOW HEADS
NORTHEAST. WINDS THEN STAY BELOW 25 KNOTS FOR THE REST OF THE
PERIOD.
&&

.HYDROLOGY...
ISSUED AT 543 AM EDT TUE APR 30 2013

UNSEASONABLY WARM AIR AND HIGHER DEWPOINTS WILL CONTINUE TO FAVOR
RAPID MELTING OF THE REMAINING SNOWPACK ACROSS NORTH CENTRAL AND
WEST UPPER MICHIGAN KEEPING RIVER LEVELS HIGH. A COLD FRONT MOVING
THROUGH THIS AFTERNOON INTO TONIGHT MAY PRODUCE ADDITIONAL RAINFALL
OF A QUARTER TO HALF INCH IN SOME LOCATIONS. MUCH COOLER CONDITIONS
EXPECTED FOR REST OF WEEK COMBINED WITH LIMITED SNOWFALL SHOULD LEAD
TO A SLOW FALL IN RIVER LEVELS. ADDITIONAL CHANCES OF RAIN AND
EVEN SNOW OVER THE WEST ARE POSSIBLE WEDNESDAY AFTERNOON INTO
THURSDAY NIGHT...WITH THE HEAVIEST PRECIPITATION OVER THE WESTERN
THIRD OF UPPER MICHIGAN. SO...EVEN THOUGH TEMPERATURES WILL BE
COOLER THIS MAY BE OFFSET BY THE ADDITIONAL PRECIPITATION.

RIVERS OF PARTICULAR CONCERN DUE TO MELTING WILL BE THE BLACK RIVER
NEAR BESSEMER...THE TRAP ROCK RIVER...THE STURGEON RIVER OF
BARAGA/HOUGHTON COUNTIES...THE PESHEKEE RIVER...THE PAINT RIVER NEAR
CRYSTAL FALLS...THE ONTONAGON RIVER AT EWEN...THE CHOCOLAY RIVER
NEAR HARVEY...AND EVENTUALLY THE MICHIGAMME RIVER NEAR REPUBLIC AND
WITCH LAKE. MELTING SCENARIOS STILL LEAD TO SIGNIFICANT UNCERTAINTY WITH
THE RIVER FORECASTS FOR THE PESHEKEE AND MICHIGAMME BASINS WHERE
MOST OF THE MELTING HAS NOT HIT ANY OBSERVED RIVER POINTS. AT
OTHER LOCATIONS...SUFFICIENT RUNOFF FROM MELTING HAS BEEN OBSERVED
TO MORE ACCURATELY ASSESS THE MELT RATES FOR THE RIVER MODELS.

AN NWS SURVEY OF THE PESHEKEE RIVER MONDAY MORNING REVEALED THICK
ICE COVERING MOST OF THE RIVER NEAR AND DOWNSTREAM OF THE CHPM4
RIVER GAUGING LOCATION/AUTOMATED GAUGE DISCONTINUED BUT OBS ARE
BEING TAKEN USING A WIREWEIGHT GAUGE AT THE LOCATION/ AND THICK ICE
COVER ON MOST OF LAKE MICHIGAMME WHICH THE PESHEKEE DRAINS INTO. A
FEW ICE JAMS WERE NOTED MONDAY MORNING WHICH COULD CAUSE SOME
PROBLEMS OVER THE NEXT COUPLE OF DAYS AS THE RIVER RISES.

MAIN STEM RIVERS ARE NOT THE ONLY HAZARD...AS THERE IS ALSO A THREAT
OF AREAL FLOODING WITH SMALLER CREEKS/STREAMS AND STANDING WATER ON
ROADS. AREAL TYPE FLOODING HAS BEEN REPORTED...THE MOST WIDESPREAD
OVER GOGEBIC COUNTY WHERE AN AREAL FLOOD WARNING WAS ISSUED THROUGH
TUESDAY EVENING. FOR COMPLETE DETAILS...SEE THE LATEST RIVER FLOOD
WATCHES...WARNINGS AND ADVISORIES.

&&

.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
  FLASH FLOOD WATCH THROUGH THIS EVENING FOR MIZ009.

LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&

$$

SHORT TERM...JLB
LONG TERM...07
AVIATION...MCD
MARINE...07
HYDROLOGY...JLB







AREA FORECAST DISCUSSION

NWS MARQUETTE MI

 517 AM EDT TUE APR 30 2013

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 516 AM EDT TUE APR 30 2013

WV IMAGERY AND RUC ANALYSIS INDICATED A BROAD MID/UPPER LEVEL TROUGH
OVER THE NW CONUS RESULTING IN SW FLOW FROM THE CNTRL PLAINS TO THE
NRN GREAT LAKES. A VIGOROUS SHORTWAVE TROUGH WAS LCOATED OVER THE SE
CORNER OF SASK INTO FAR NW ND.  AT THE SFC...LOW PRES WAS LOCATED
OVER NE SOUTH DAKOTA WITH A WARM FRONT THROUGH SE MN INTO SRN WI. A
LLJ AHEAD OF THE WITH INFLOW OF MOIST/UNSTABLE AIR SUPPORTED TSRA
INTO SRN WI AND CNTRL LAKE MI. ISOLD SHOWERS NEAR ESC-ISQ HAD
DIMINISHED AS THE STRONGER CONVECTION DEVELOPED TO THE SOUTH.
UPSTREAM...A WEAK SHRTWV AHEAD OF THE LOW  SUPPORTED A BAND OF
SHRA/TSRA OVER NRN MN.

RADAR AND SATELLITE TRENDS SUGGEST THAT MOST OF THE CONVECTION OVER
WI WILL SLIDE JUST SOUTH OF THE CWA BUT MAY EXPAND JUST ENOUGH FOR
SOME SCT SHRA/TSRA...MAINLY SOUTH OF A LINE FROM IMT-ERY. AS THE SD
LOW LIFTS NORTHEAST THROUGH THROUGH NW MN TO NW ONTARIO...WAA AND
MOISTURE ADVECTION WILL INCREASE WITH THE STRENGTHENING SRLY FLOW.
TEMPS CLIMBING INTO THE LOWER TO MID 70S COMBINED WITH DEWPOINTS IN
THE LOWER TO MID 50S WILL RESULT IN MLCAPE VALUES IN THE 600-1200
J/KG RANGE BY THIS AFTERNOON. THE COLD FRONT DRAPED TO THE SOUTH OF
THE LOW MOVING INTO THE WEST UPPER MI THIS AFTERNOON WILL BE THE
MAIN FOCUS FOR SHRA/TSRA DEVELOPMENT. ALTHOUGH THE STRONGEST QVECTOR
CONV WILL BE WELL NORTH OF THE REGION...EVEN MODEST LOW LEVEL CONV
ALONG AND AHEAD OF THE FRONT SHOULD SUPPORT SCT TSRA THIS AFTERNOON
INTO THIS EVENING. SOME STRONGER STORMS MAY BE POSSIBLE WITH 0-6KM
SHEAR VALUES IN THE 40-50 KT...BUT THE GREATER SVR POTENTIAL IS
EXPECTED FARTHER SOUTH(PER SPC) WHERE INSTABILITY WILL BE GREATER.
THE HIGHEST POPS VALUES WERE INCLUDED OVER THE WEST LATE THIS
AFTERNOON AND INTO THE CNTRL AND EAST THIS EVENING...BEFORE
SHRA/TSRA WEAKEN WITH DIURNAL COOLING.

.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 442 AM EDT TUE APR 30 2013

NAM SHOWS A 500 MB RIDGE OVER THE EASTERN U.S. WITH A TROUGH IN THE
NORTHERN AND CENTRAL ROCKIES AND A CLOSED 500 MB LOW OVER THE GULF
COAST 12Z WED. THE TROUGH MOVES INTO THE NORTHERN PLAINS 00Z THU AND
INTO THE UPPER GREAT LAKES ON THU. NAM SHOWING SOME 850-500 MB
Q-VECTOR CONVERGENCE WITH DEEPER MOISTURE OVER THE WEST HALF OF
UPPER MICHIGAN 12Z WED WHICH REMAINS THROUGH 00Z THU. THIS NARROW
RIBBON OF DEEPER MOISTURE REMAINS OVER THE WESTERN CWA THROUGH 12Z
THU BEFORE THIS MOVES AND EXPANDS EASTWARD. GFS AND ECMWF SHOW ABOUT
THE SAME THING AS WELL.

THIS FORECAST PERIOD GETS DOMINATED BY COLDER AIR COMING INTO THE
AREA AND THERE COULD BE A RAIN/SNOW MIX ACROSS THE WESTERN U.P.
STARTING LATE WED NIGHT AND LASTING INTO THU NIGHT. THE WESTERN CWA
ALSO HAS THE BEST MOISTURE AND THEREFORE WILL HAVE THE HIGHEST POPS
WHILE THE EAST IS FURTHER AWAY FROM THE FRONTAL BAND PCPN THAT SETS
UP AND IS IN WARMER AIR AS WELL. QUITE A GRADIENT SETS UP IN
TEMPERATURES WITH THE COLDEST READINGS ACROSS THE WEST AND THE
WARMEST IN THE EAST FOR THROUGH THU. QPF WILL CONTINUE TO BE
HEAVIEST OVER THE WEST WITH ANYWHERE FROM 0.25 INCH ACROSS THE EAST
TO 1.25 IN THE WEST FROM WED TO THU NIGHT. THE COLD AIR DOES NOT
ARRIVE UNTIL LATE WED NIGHT ACROSS THE WEST AND COULD SEE ANYWHERE
FROM 1 TO 6 INCHES WEST OF A LINE FROM BIG BAY TO IRON RIVER FROM
WED NIGHT INTO THU NIGHT. DID RAISE TEMPERATURES A BIT FOR WED WITH
LATER ARRIVAL OF COLDER AIR AND RAISED THEM WED NIGHT AS WELL A
COUPLE DEGREES. OTHERWISE...DID NOT MAKE TOO MANY CHANGES TO THE
GOING FORECAST EXCEPT TO GO A BIT DRIER IN THE EASTERN CWA WHICH IS
FURTHER AWAY FROM THE FRONTAL BAND.

IN THE EXTENDED...GFS AND ECMWF SHOW A 500 MB TROUGH AND CLOSED LOW
OVER THE CENTRAL PLAINS 12Z FRI WITH A RIDGE OVER THE EASTERN U.S.
PATTERN DOES NOT CHANGE MUCH FOR 12Z SAT WITH THE 500 MB RIDGE
REMAINING STATIONARY. THIS 500 MB LOW CONTINUES TO SPIN ACROSS THE
CENTRAL PLAINS 12Z SUN FOR THE ECMWF AND THE GFS IS MUCH FURTHER
SOUTH WITH THE PLACEMENT OF THE 500 MB LOW. GFS CONTINUES TO MOVE
THE LOW EAST WELL SOUTH OF THE AREA 12Z MON WHILE THE ECMWF TAKES
THE LOW AND ASSOCIATED TROUGH THROUGH THE AREA. MANUAL PROGS KIND OF
WASH THIS SYSTEM OUT WITH TIME WITH WEAK SFC PRESSURE PATTERNS. WITH
SLOW CHANGE IN UPPER PATTERN...PERSISTENCE LOOKS TO BE THE WAY TO GO
FOR THIS FORECAST. TEMPERATURES WILL SLOWLY WARM THIS EXTENDED
FORECAST PERIOD FROM BELOW NORMAL TO NEAR NORMAL AND WILL BE WET
WITH PCPN CHANCES ALMOST EACH PERIOD.
&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 442 AM EDT TUE APR 30 2013

WITH THE ARRIVAL OF MOIST AIR FOG HAS DEVELOPED AT THE KCMX/KSAW
SITES....AND WITH GENERAL UPSLOPE FLOW IN THESE AREAS EXPECT THE
IFR/LIFR CONDITIONS TO CONTINUE THROUGH THE OVERNIGHT PERIOD.
DOWNSLOPING WINDS WILL LIKELY INHIBIT THE DEVELOPMENT OF ANY
SIGNIFICANT LOWER CEILINGS/VIS AT KIWD TONIGHT. A COLD FRONT WILL
CROSS UPPER MICHIGAN DURING THE DAYTIME TUESDAY...BRINGING SHOWERS
TO EACH OF THE TAF SITES...WITH KIWD/KCMX CLEARING OUT FOR THE LATE
AFTERNOON/EARLY EVENING TIME FRAME FOR A SHORT TIME. ISOLATED
THUNDERSTORMS ARE POSSIBLE TOMORROW...ESPECIALLY AT KSAW...BUT
CONFIDENCE WAS NOT HIGH ENOUGH TO INCLUDE IN THE TAF.
OTHERWISE...WITH THE APPROACHING FRONT AND
HEATING/MIXING...SOUTHERLY WINDS ARE EXPECTED TO BE GUSTING TO NEAR
25KTS TOWARDS THE AFTERNOON HOURS BEFORE SHIFTING TO THE WEST.
LASTLY...LLWS IS STILL POSSIBLE TONIGHT AT THE TAF SITES WITH
STRONGER SOUTHERLY WINDS ALOFT.
&&

.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 442 AM EDT TUE APR 30 2013

NO GALES SEEN IN THIS FORECAST PERIOD. WINDS DO GET UP TO 30 KNOTS
ACROSS THE EAST AND NORTH CENTRAL TODAY AS A SFC LOW HEADS
NORTHEAST. WINDS THEN STAY BELOW 25 KNOTS FOR THE REST OF THE
PERIOD.
&&

.HYDROLOGY...
ISSUED AT 443 PM EDT MON APR 29 2013

ANOTHER DAY OF WARM TEMPERATURES HAS CONTINUED THE SNOW MELT AND
THE RISING RIVER LEVELS ACROSS THE AREA. FORTUNATELY...RAINFALL
AMOUNTS OVER THE LAST COUPLE OF DAYS HAVE BEEN FAIRLY LIGHT AND HAS
KEPT THE FLOODING CONCERNS TO THE SNOW MELT. WITH 5-20 INCHES OF
SNOW STILL REMAINING OVER WESTERN UPPER MICHIGAN...EXPECT THE WARM
TEMPERATURES TONIGHT AND TUESDAY TO CONTINUE THE SNOWMELT AND KEEP
RIVER LEVELS AT HIGHER LEVELS. A COLD FRONT MOVING THROUGH TUESDAY
AFTERNOON INTO TUESDAY NIGHT MAY PRODUCE ADDITIONAL RISES ON THE
ALREADY SWOLLEN RIVERS ACROSS THE AREA. MUCH COOLER TEMPERATURES
EXPECTED FOR REST OF WEEK BEHIND THE FRONT...WHICH COMBINED WITH
LIMITED SNOWFALL SHOULD LEAD TO A SLOW FALL IN RIVER LEVELS THROUGH
THE REST OF THE WEEK. ADDITIONAL CHANCES OF RAIN AND EVEN SNOW OVER
THE WEST ARE POSSIBLE WEDNESDAY AFTERNOON INTO THURSDAY NIGHT...WITH
THE HEAVIEST PRECIPITATION OVER THE WESTERN THIRD OF UPPER MICHIGAN.
SO...EVEN THOUGH TEMPERATURES WILL BE COOLER THIS MAY BE OFFSET BY
THE ADDITIONAL PRECIPITATION THAT MAY OCCUR.

RIVERS OF PARTICULAR CONCERN DUE TO MELTING WILL BE THE TRAP ROCK
RIVER...THE STURGEON RIVER OF BARAGA/HOUGHTON COUNTIES...THE
PESHEKEE RIVER...THE PAINT RIVER NEAR CRYSTAL FALLS...THE ONTONAGON
RIVER AT EWEN...THE CHOCOLAY RIVER NEAR HARVEY...AND EVENTUALLY THE
MICHIGAMME RIVER NEAR REPUBLIC AND WITCH LAKE. MELTING SCENARIOS
STILL REMAIN THE BIGGEST CONFIDENCE REDUCERS IN RIVER FORECASTS FOR
THE PESHEKEE AND MICHIGAMME BASINS WHERE MOST OF THE MELTING HAS NOT
HIT ANY OBSERVED RIVER POINTS YET. AT OTHER LOCATIONS...SUFFICIENT
RUNOFF FROM MELTING HAS BEEN OBSERVED TO MORE ACCURATELY GET A
HANDLE OF MELT RATES FOR THE RIVER MODELS. NWS SURVEY OF THE
PESHEKEE RIVER THIS MORNING REVEALED THICK ICE COVERING MOST OF THE
RIVER NEAR AND DOWNSTREAM OF THE CHPM4 RIVER GAUGING LOCATION
/AUTOMATED GAUGE DISCONTINUED BUT OBS ARE BEING TAKEN USING A WIRE
WEIGHT GAUGE AT THE LOCATION/ AND THICK ICE COVER ON MOST OF LAKE
MICHIGAMME WHICH THE PESHEKEE DRAINS INTO. A FEW ICE JAMS WERE
NOTED THIS MORNING AND THIS COULD CAUSE SOME ISSUES OVER THE NEXT
COUPLE OF DAYS AS THE RIVER RISES. MAIN STEM RIVERS ARE NOT THE ONLY
HAZARD...AS THERE IS ALSO A THREAT OF AREAL FLOOD PROBLEMS WITH
SMALLER CREEKS/STREAMS AND STANDING WATER ON ROADS. HAVE RECEIVED
SOME SPORADIC REPORTS OF AREAL TYPE FLOODING...WITH THE MOST
WIDESPREAD OVER GOGEBIC COUNTY...SO HAVE ISSUED A AREAL FLOOD
ADVISORY THROUGH TUESDAY FOR GOGEBIC COUNTY. FOR COMPLETE
DETAILS...SEE THE LATEST RIVER FLOOD WATCHES...WARNINGS AND
ADVISORIES.
&&

.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
  FLASH FLOOD WATCH THROUGH THIS EVENING FOR MIZ009.

LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&

$$

SHORT TERM...JLB
LONG TERM...07
AVIATION...MCD
MARINE...07
HYDROLOGY...SRF







AREA FORECAST DISCUSSION...UPDATED AVIATION

NWS ST LOUIS MO

 1153 PM CDT MON APR 29 2013

.UPDATE...
ISSUED AT 912 PM CDT MON APR 29 2013

HAVE REMOVED RAIN CHANCES FOR TONIGHT. THUNDERSTORMS HAVE DEVELOPED
IN THE LAST 1-2 HOURS WELL NORTH OF THE CWA IN NORTH CENTRAL AND
NORTHEAST IOWA ALONG A WARM FRONT. CHANCES FOR RAIN OVER NORTHEAST
MO/WEST CENTRAL IL LOOK TO BE DIMINISHING AS 00Z 700MB UPPER
ANALYSIS SHOWED WEAK WARM AIR ADVECTION MOVING INTO NORTHERN MO.
RAP FORECAST SOUNDING AT KUIN DOES SHOW WARMING BETWEEN 900-700MB
OVERNIGHT WITH WEAKENING CAPE.

LITTLE CHANGE NEEDED TO THE REST OF THE FORECAST AS GRADIENT WINDS
WILL STAY UP ENOUGH TO KEEP TEMPERATURES FROM FALLING BELOW GOING
LOWS.

BRITT
&&

.SHORT TERM...(THROUGH LATE TONIGHT)
ISSUED AT 256 PM CDT MON APR 29 2013

PRIMARY WEATHER CONCERN FOR TONIGHT IS THE POSSIBILITY OF CONVECTION
ACROSS NORTHERN MISSOURI AND WEST CENTRAL ILLINOIS.  RUC CONTINUES
TO FORECAST COPIOUS AMOUNTS OF CAPE SOUTH OF A Q-STATIONARY FRONT
EXTENDING THROUGH NORTHEAST KANSAS INTO SOUTHEAST NEBRASKA AND
WESTERN IOWA LATE THIS AFTERNOON.  GREATEST VALUES EXCEED 4000 J/KG
ACROSS PARTS OF WESTERN AND CENTRAL MISSOURI.  HOWEVER...RUC ALSO
APPEARS TO BE 3 TO 5 DEGREES TOO MOIST ON DEWPOINT FORECASTS LATER
THIS AFTERNOON INTO THE EVENING WHICH WOULD DEFINITELY ACCOUNT FOR
THE GIHEMOUS CAPE VALUES.  THAT BEING SAID...THERE IS SOME
AGITATED CU OVER SOUTH CENTRAL MISSOURI AND ONE LONE THUNDERSTORM
OVER NORTHERN ARKANSAS...SO THERE`S OBVIOUSLY SOME INSTABILITY OUT
THERE.  CURRENT THINKING IS THAT THE ISOLATED CONVECTION OVER SOUTH
CENTRAL MISSOURI WON`T MAKE IT TO OUR AREA...AND THAT CONVECTION
WILL FIRE CLOSER TO THE BAROCLINIC ZONE IN NEBRASKA LATE THIS
AFTERNOON/EARLY EVENING AND RIDE UP ACROSS IOWA.  COULD SEE THE TAIL
END OF ANY CONVECTIVE COMPLEX THAT FORMS AFFECT NORTHERN PORTIONS OF
THE CWFA SO HAVE KEPT LOW CHANCE POPS UP THERE.  OTHERWISE...SHOULD
BE MILD AND QUIET NIGHT.

CARNEY

.LONG TERM...(TUESDAY THROUGH NEXT MONDAY)
ISSUED AT 256 PM CDT MON APR 29 2013

TUESDAY THROUGH THURSDAY...CONFIDENCE MEDIUM

WELL ABOVE NORMAL TEMPERATURES ARE EXPECTED TUESDAY AND WEDNESDAY
AHEAD OF THE DIGGING TROF AND COLD FRONT. CAN`T ARGUE MUCH WITH MOS
GUIDANCE WITH HIGHS IN THE LOWER TO MIDDLE 80S AND LOWS IN THE 60S.

MODEL GUIDANCE IN GOOD AGREEMENT THAT COLD FRONT WILL WAIT UNTIL
WEDNESDAY NIGHT AND THURSDAY MORNING TO START MOVING ACROSS THE CWA.
PRECIPITATION CHANCES TO INCREASE FROM THE WEST...BUT BELIEVE A
LARGE PART OF THE CWA WILL REMAIN DRY THROUGH THURSDAY MORNING.

THIS WILL CHANGE THURSDAY AFTERNOON. THE MAIN BAND OF RAIN WILL EDGE
INTO CENTRAL AND NORTHEAST MISSOURI...WHILE CONVECTION FIRES ON THE
FRONT ITSELF ALONG AND EAST OF THE MISSISSIPPI RIVER. I AM SURE
SOMEONE IN THE MIDDLE OF THESE TWO AREAS OF PRECIPITATION MAY REMAIN
DRY...BUT IT IS TOO FAR OUT TO GET TOO CUTE WITH POP GRADIENTS.

SHOULD BE QUITE A TEMPERATURE CONTRAST ACROSS THE CWA ON THURSDAY
WITH STEADY OR SLOWLY FALLING TEMPERATURES IN THE 40S IN THE WESTERN
CWA...TO THE LOW/MIDDLE 70S IN SOUTH CENTRAL ILLINOIS.

FRIDAY THROUGH MONDAY...CONFIDENCE LOW

MODELS ARE STILL HAVING SOME DIFFICULTY IN HOW THEY HANDLE THE TRACK
OF THE CLOSED OFF LOW LATE THIS WEEK AND WEEKEND. PREFER TO KEEP
FORECAST TREND THE SAME...ESSENTIALLY FOLLOWING HPC GUIDANCE AND 12Z
ECWMF...WITH THE CLOSED OFF LOW DEVELOPING TO OUR WEST AND SPINNING
NORTHEAST ACROSS THE MIDWEST TOWARD THE GREAT LAKES THIS WEEKEND.

MARCHED THE MAIN BAND OF RAIN EAST THURSDAY NIGHT AND FRIDAY WITH
LIKELY POPS AND THEN CONTINUED LOW CHANCE POPS FOR RAIN SHOWERS
THROUGH MONDAY AS AREA EXPECTED TO REMAIN AT LEAST IN THE
VICINITY OF THE COLD CORE SYSTEM. FORECAST RAINFALL AMOUNTS WITH
THIS SOLUTION WOULD BE ON THE ORDER OF 1 TO 1.5 INCHES FOR THE
EVENT.

TEMPERATURES STILL ON TRACK TO FALL BACK BELOW NORMAL FRIDAY AND
SATURDAY...BUT SLOWLY WARM SUNDAY AND MONDAY AS INFLUENCE OF THE
SYSTEM WAINS BY THE BEGINNING OF NEXT WEEK.

NOTE...THE 12Z GFS AND GEM CAME IN QUITE A BIT FURTHER TO THE
SOUTHWEST AND MUCH SLOWER WITH THE SYSTEM...WHICH WOULD RESULT IN A
PROLONGED PERIOD OF RAIN AS THE FRONT AND TROPICAL FETCH PARK ITSELF
ACROSS THE MISSISSIPPI RIVER VALLEY FOR THE ENTIRE WEEKEND. THIS
SOLUTION WOULD YIELD WIDESPREAD RAINFALL AMOUNTS IN EXCESS OF 2
INCHES...WITH SOME LOCALS OVER 4 INCHES.

CVKING
&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1151 PM CDT MON APR 29 2013

VFR CONDITIONS TO PREVAIL THROUGH THE FORECAST PERIOD. SO MAIN
ISSUE CONTINUES TO BE THE WINDS AND LLWS OVER REGION. WITH LIGHT
SOUTH WINDS AT SURFACE AND STRONG SOUTHWEST LOW LEVEL JET...LLWS A
GOOD BET OVER CENTRAL/NORTHEAST MO...WEST CENTRAL IL...SO KEPT
MENTION IN TAFS. OTHERWISE...THESE GUSTY WINDS TO MIX DOWN TO THE
SURFACE WITH GUSTS TO NEAR 25KTS AT TIMES BY MID MORNING...BEFORE
DIMINISHING AFTER 02Z WEDNESDAY. SOME DIURNAL CU IS POSSIBLE
BEFORE DISSIPATING TOWARDS SUNSET.

SPECIFICS FOR KSTL...VFR CONDITIONS TO PREVAIL THROUGH THE FORECAST
PERIOD. SO MAIN ISSUE CONTINUES TO BE THE WINDS. LIGHT SOUTH WINDS
TO PREVAIL THROUGH 15Z TUESDAY...THEN GUSTY WINDS ALOFT TO MIX
DOWN TO THE SURFACE WITH GUSTS TO NEAR 25KTS AT TIMES...BEFORE
DIMINISHING AFTER 02Z WEDNESDAY. SOME DIURNAL CU IS POSSIBLE
BEFORE DISSIPATING TOWARDS SUNSET. STILL SOME CONCERN THAT WINDS
COULD VEER A BIT MORE TO THE SOUTHWEST ON TUESDAY AFFECTING RUNWAY
CONFIGURATION...WILL KEEP AN EYE ON IT FOR NOW.

BYRD
&&

.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&

$$
WFO LSX







AREA FORECAST DISCUSSION

NWS OMAHA/VALLEY NE

 1152 PM CDT MON APR 29 2013

.AVIATION...
06Z TAFS FOR KOMA...KLNK...KOFK.
A FEW CELLS TRIED TO GET GOING...HOWEVER LOOKS LIKE THE TAF SITES
SHOULD REMAIN DRY OVERNIGHT...SO HAVE NOT MENTIONED ANY CIGS BLO
FL100 UNTIL TUESDAY EVENING. LOW LEVEL WIND SHEAR INCLUDED
THROUGH 12Z AT KOMA AND KLNK. SURFACE WINDS SHOULD BE FROM THE
SOUTH OR SOUTHWEST AT 10 TO 15KTS AHEAD OF THE FRONT...WITH A
FRONTAL PASSAGE AT KOFK 10-12Z AND CLOSER TO 18Z AT KOMA AND KLNK.
NORTH WINDS WILL PICK UP AROUND 15KTS WITH HIGHER GUSTS BEHIND THE
FRONT. SHOWERS AND THUNDERSTORMS MAY DEVELOP LATE IN THE AFTERNOON
NEAR KLNK AND KOMA...BUT LEFT OUT UNTIL THE EVENING FOR NOW.

ZAPOTOCNY

&&

.PREV DISCUSSION... /ISSUED 903 PM CDT MON APR 29 2013/

UPDATE...
MAIN FORECAST CONCERN TONIGHT WILL BE CONVECTIVE POTENTIAL...AND
ADJUSTED CLOUDS...WINDS...AND DEWPOINTS TOO.

DISCUSSION...
THE WEAK H5 SHORTWAVE MOVING ACROSS THE AREA APPEARS TO HAVE
TOUCHED OFF SOME ISOLATED THUNDERSTORMS IN IOWA AND NOW WILL BE
WATCHING TO SEE HOW THUNDERSTORMS WILL DEVELOP AS THE LOW LEVEL
JET INCREASES. SEVERAL OF THE SHORT RANGE MODELS DEVELOPED
CONVECTION IN SOUTHEAST NEBRASKA AND SOUTHWEST IOWA...ALONG A WEAK
BOUNDARY AS DEEPER MOISTURE IS DRAWN NORTHWARD WITH THE INCREASING
LLJ. THE LATEST RAP AND 00Z NAM...ARE NOW MAINLY DRY THIS
EVENING. LEFT IN THE EVENING CHANCE FOR THUNDERSTORMS...BUT THINK
WITH VEERING H85 JET...ANYTHING THAT FORMS WILL QUICKLY SHIFT
NORTHEAST.

ZAPOTOCNY

PREV DISCUSSION... /ISSUED 253 PM CDT MON APR 29 2013/

SHORT TERM...TONIGHT THROUGH THURSDAY.

SURFACE COLD FRONT THAT HAD MOVED INTO SOUTHEAST NEBRASKA
OVERNIGHT HAD PRETTY MUCH WASHED OUT BY 19Z WITH SOUTHERLY WINDS
NOTED ACROSS THE AREA. STILL SOME CHANCE OF SHOWERS AND
THUNDERSTORMS FOR SOUTHEAST NEBRASKA AND SOUTHWEST IOWA THIS
EVENING AS A MID LEVEL WAVE OVER WESTERN NEBRASKA MOVES EAST WITH
BOTH THE GFS AND NAM SHOWING A POCKET OF ELEVATED INSTABILITY OVER
THAT AREA DURING THIS TIME BEFORE MOVING OFF TO THE EAST AFTER
06Z.

MODELS STILL SHOW SIMILAR TIMING FOR THE COLD FRONT JUST COMING
INTO THE NORTHERN PLAINS THIS AFTERNOON REACHING THE NORTHWEST
PORTION OF THE CWA BY 12Z TUESDAY...THEN SOUTHEAST CORNER OF
NEBRASKA BY LATE TUESDAY AFTERNOON. LITTLE CHANGE TO CURRENT
TREND OF INCREASING POPS STARTING TUESDAY AFTERNOON AND EXTENDING
INTO WEDNESDAY NIGHT AS THE SURFACE FRONT DROPS SLOWLY SOUTH AND
UPPER WAVE DIGS INTO THE PLAINS REGION. EASTERN PARTS OF THE AREA
STILL LOOK TO HAVE A CONTINUING CHANCE OF SHOWERS ON THURSDAY AS
CUTOFF LOW DEVELOPS IN VICINITY OF EASTERN KANSAS. TEMPERATURES
ALSO CONTINUE TO TREND BELOW NORMAL AS THE COLD AIR ASSOCIATED
WITH THE UPPER SYSTEM LINGERS OVER THE AREA. SOME SNOW POSSIBLE
WEDNESDAY NIGHT INTO EARLY THURSDAY FOR MUCH OF THE AREA HOWEVER
LITTLE ACCUMULATION EXPECTED AT THIS TIME.

LONG TERM...THURSDAY NIGHT THROUGH MONDAY.

PLACEMENT AND MOVEMENT OF THE CLOSED LOW STILL LOOKS TO BE THE
MAIN PROBLEM IN THE EXTENDED PERIOD. 12Z ECMWF APPEARS TO BE MORE
CONSISTENT WITH PREVIOUS MODEL RUNS WHILE GFS NOW TAKES THE
SYSTEM FURTHER SOUTH. SOME THREAT OF PRECIP INTO THE WEEKEND YET
WITH POTENTIAL FOR RAIN OR SNOW SHOWERS DEPENDING ON ACTUAL TRACK
OF THE SYSTEM.

FOBERT

&&

.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&

$$




AREA FORECAST DISCUSSION

NWS WILMINGTON OH

 136 AM EDT TUE APR 30 2013

.SYNOPSIS...
HIGH PRESSURE AND A DRIER AIRMASS WILL BUILD INTO THE REGION
THROUGH WEDNESDAY. A SLOW MOVING UPPER LEVEL LOW WILL DIVE SOUTH
THROUGH THE CENTRAL U.S. AT THE END OF THE WEEK WITH AN
ACCOMPANYING SURFACE LOW MOVING NORTH ALONG THE MISSISSIPPI. AT
SOME POINT OVER THE WEEKEND...THESE SYSTEMS WILL BECOME STACKED
AND BEGIN TO TRACK EAST THROUGH THE OHIO VALLEY.

&&

.NEAR TERM /UNTIL 6 AM THIS MORNING/...
CLOUD DECK HAS RAPIDLY ERODED OVER THE PAST COUPLE HOURS WHICH IS
RIGHT IN LINE WITH THE 00Z 4/30 NAM AND RECENT RAP RUNS. BOTH THE
NAM AND RAP ALSO HAVE UPSTREAM CLOUDS OVER IN/IL GRADUALLY ERODING
AS THEY APPROACH THE AREA OVERNIGHT. KEPT MAJORITY OF FA UNDER
MOSTLY CLEAR SKIES TONIGHT WITH THE EXCEPTION OF PARTLY CLOUDY IN
THE FAR NORTH. MAIN FORECAST CONCERN WILL BE POSSIBILITY OFF FOG
GIVEN PLENTIFUL LOW LEVEL MOISTURE (DEW POINTS STILL IN THE
50S)...LIGHT TO CALM WINDS...AND A FAVORABLE SETUP FOR RADIATIONAL
COOLING. PATCHY DENSE FOG WILL BE A POSSIBILITY...ESPECIALLY IN
LOW LYING AREAS. PREVIOUS MIN TEMP FORECAST IN THE LOWER 50S STILL
LOOKS TO BE ON TRACK.

&&

.SHORT TERM /6 AM THIS MORNING THROUGH WEDNESDAY NIGHT/...
MID AND UPPER LEVEL RIDGING WILL DEVELOP ACROSS THE OHIO VALLEY
TUESDAY INTO WEDNESDAY AHEAD OF THE DIGGING UPPER LOW IN THE PLAINS.
THIS WILL RESULT IN DRY CONDITIONS AND A DECENT WARM UP THROUGH
MIDWEEK. TEMPERATURES ON TUESDAY SHOULD PUSH INTO THE MID TO UPPER
70S WITH HIGHS ON WEDNESDAY IN THE UPPER 70S TO LOWER 80S.
OVERNIGHT LOWS WILL BE SEASONABLY MILD IN THE LOW TO MID 50S. THIS
IS SLIGHTLY ABOVE CLIMO NORMALS IN THE UPPER 40S.

&&

.LONG TERM /THURSDAY THROUGH MONDAY/...
ENERGY DIGGING FROM THE NRN ROCKIES WILL CARVE OUT AN UPPER LEVEL
TROF OVER THE NATIONS MID SECTION WITH AN UPPER LOW EVENTUALLY
CLOSING OFF OVER THE CENTRAL PLAINS BY FRIDAY.

STRONG RIDGING AHEAD OF THIS SYSTEM WILL PROVIDE WARM TEMPERATURES
THURSDAY WITH HIGHS 7 TO 10 DEGREES ABOVE NORMAL...RANGING FROM MID
70S NW TO NEAR 80 SE.

NUMERICAL MODEL SOLNS HAVE BEEN SHOWING A HIGHER THAN NORMAL DEGREE
OF SPREAD REGARDING PLACEMENT AND MOVEMENT OF THIS UPPER LOW. ECMWF
HAS HAD BEST RUN TO RUN CONSISTENCY. PREVIOUS ECMWF RUNS AND CMC
RUNS WERE STALLING OUT THE EASTWARD PROGRESSION OF THE UPPER LOW
OVER THE MID MS VLY ON FRIDAY AND THEN LIFTING IT NNW INTO THE NRN
PLAINS SATURDAY. GFS SOLN HAS FLIPPED BACK AND FORTH AND THE LATEST
RUN TAKES THE LOW VERY SLOWLY EASTWARD THRU THE LWR MS VALLEY THIS
WEEKEND AND INTO TN VLY BY EARLY NEXT WEEK...PASSING TO OUR SOUTH.
LATEST NOGAPS POINTS TOWARD THE NW SOLN...WHILE THE GFS ENSEMBLE
MEAN SHOWS EVIDENCE FOR THE LOW STALLING TO OUR WEST. LATEST 12Z
DETERMINISTIC ECMWF SOLN DIGS THE LOW FARTHER SOUTH AND THEN LIFTS
IT NE THIS WEEKEND INTO THE UPPER MS VLY BY SUNDAY EVENING AND THEN
ACRS THE GREAT LAKES EARLY NEXT WEEK.

WITH A WIDE ARRAY OF SOLNS...UNCERTAINTY IS CONSIDERABLY HIGHER THAN
NORMAL FOR THE FCST NEXT WEEK END INTO EARLY NEXT WEEK. HAVE TRENDED
THE FCST SOLN TOWARD THE ECMWF SOLN WITH THE UPR LOW PASSING TO OUR
NORTH. DUE TO LOW CONFIDENCE HAVE LIMITED POPS TO SLIGHT CHC ACRS
THE FAR WEST FRIDAY WITH THE APPROACH OF SFC FRONTAL SYSTEM. WILL
CONTINUE ONLY SLIGHT CHC POPS SATURDAY ACRS THE WEST. HAVE SPREAD
LOW CHANCE POPS ACRS ENTIRE FA FOR SUNDAY/MONDAY TIME FRAME.

TEMP WISE...AFTER ABOVE NORMAL READINGS ON THURSDAY...TEMPS LOOK TO
BE A LTL CLOSER TO NORMAL FRIDAY AND INTO NEXT WEEKEND.

&&

.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
SKIES HAVE CLEARED ACROSS THE AREA EARLY THIS MORNING AND THIS HAS
ALLOWED FOR SOME AREAS OF MAINLY MVFR BR TO DEVELOP. WITH SOME
LINGERING LOW LEVEL MOISTURE...EXPECT MVFR TO OCCASIONALLY IFR BR
TO PERSIST THROUGH DAYBREAK. THE EXCEPTION WILL BE AT KLUK WHERE
RIVER VALLEY FOG WILL KEEP THEM PRIMARILY VLIFR THROUGH DAYBREAK.
MID LEVEL RIDGING WILL OTHERWISE PROVIDE FOR DRY CONDITIONS
THROUGH THE TAF PERIOD WITH JUST A FEW CU DEVELOPING THROUGH LATE
MORNING INTO EARLY AFTERNOON.

OUTLOOK...NO SIGNIFICANT WEATHER EXPECTED.

&&

.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.

&&

$$
SYNOPSIS...FRANKS
NEAR TERM...KURZ
SHORT TERM...FRANKS
LONG TERM...AR
AVIATION...JGL








AREA FORECAST DISCUSSION

NWS LA CROSSE WI

 1145 PM CDT MON APR 29 2013

.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 324 PM CDT MON APR 29 2013

THE MAIN FOCUS TONIGHT INTO TOMORROW IS ON THE CHANCES FOR
THUNDERSTORMS TO GO ALONG WITH HOW WARM IT WILL GET BEFORE A COLD
FRONT SWINGS THROUGH TOMORROW.

CURRENTLY...A SURFACE COLD FRONT HAS STALLED OUT ACROSS THE REGION
FROM NORTH CENTRAL WISCONSIN DOWN INTO EASTERN NEBRASKA WITH A
SURFACE LOW TRACKS ALONG THE US/CANADIAN BORDER IN SOUTHERN
SASKATCHEWAN. AS THIS LOW TRACKS EAST TONIGHT...THE FRONT WILL
TRANSITION TO A WARM FRONT AND LIFT NORTH TOWARD LAKE SUPERIOR BY
TOMORROW MORNING. LOW LEVEL MOISTURE TRANSPORT WILL NOSE UP ALONG
THE FRONT AND COULD LEAD TO SOME CONVECTIVE DEVELOPMENT ALONG THIS
BOUNDARY AS A RESULT. MODIFIED 29.18Z RAP SOUNDINGS WITH SURFACE
DEW POINTS IN THE MID 50S SHOW ABOUT 1000-1500 J/KG OF 0-3KM
MUCAPE POOLING ALONG THIS FRONT AS IT LIFTS NORTH OVERNIGHT. MUCH
OF THE DEEP LAYER SHEAR APPEARS TO BE IN THE LOW LEVELS UNDER THE
INVERSION AND NOT IN THE ELEVATED PORTIONS OF THE PROFILE. WITH
FREEZING LEVELS FAIRLY LOW ALONG THE NORTHERN PERIPHERY OF THE
FRONT...EXPECT THAT SOME STRONG TO ISOLATED SEVERE STORMS WILL BE
POSSIBLE OVERNIGHT. LARGE HAIL WILL LIKELY BE THE MAIN THREAT DUE
TO THE HIGH INSTABILITY AND STABLE BOUNDARY LAYER TO PREVENT THE
STRONGEST GUSTS FROM MAKING IT TO THE SURFACE.

STRONG SOUTHERLY WINDS AHEAD OF THE MAIN COLD FRONT THAT WILL BE
INTO MINNESOTA BY TOMORROW MORNING WILL HELP TO BRING TEMPERATURES
UP TOWARD 80 FOR MUCH OF THE REGION. THE 29.12Z NAM/GFS/ECMWF HAVE
MERGED ON A SOLUTION WITH THE TIMING OF THE FRONTAL PASSAGE WITH
IT GENERALLY EXTENDING FROM NORTH CENTRAL WISCONSIN TOWARD CENTRAL
IOWA BY 18Z TOMORROW AND NEAR THE IOWA/MINNESOTA/WISCONSIN TRIPLE
POINT BY 00Z WEDNESDAY. THIS TIMING OF THE FRONT COMING THROUGH
DURING THE DIURNAL PEAK HEATING IN THE AFTERNOON LEADS TO SOME
HIGHER CONFIDENCE IN THINKING THAT THE CONVECTION WILL DEVELOP
MAINLY ACROSS SOUTHWEST WISCONSIN AND NORTHEAST IOWA IN THE LATE
AFTERNOON AND EARLY EVENING HOURS. ONE CONCERN IS THE 850MB CAP
THAT APPEARS TO HOLD ON THROUGH AT LEAST THE EARLY AFTERNOON
HOURS. MODEL SURFACE DEW POINTS APPEAR TO AGAIN PLAY A FACTOR IN
GENERATING TOO MUCH INSTABILITY AND BREAKING THE CAP BY MID
AFTERNOON. THE 29.12Z NAM COMES IN WITH SURFACE DEW POINTS IN THE
LOW 60S WHILE MIXED LAYER DEW POINTS COME IN AROUND THE MID TO
UPPER 50S AND APPEAR MORE REASONABLE. THIS KNOCKS SURFACE BASED
CAPE DOWN FROM AROUND 1000-2000 J/KG WITH NO CIN DOWN TO HAVING
ABOUT 500 J/KG OF SBCAPE AND OVER 100 J/KG OF CIN WITH THE LOWER
DEW POINTS. THE FORCING ALONG THE FRONT SHOULD BE ENOUGH TO
DEVELOP SOME STORMS...BUT THE COVERAGE WILL BE DEPENDENT UPON HOW
MUCH OF THE CAP CAN BE ERODED AHEAD OF THE FRONT. DEEP SHEAR IS A
LITTLE BETTER ACROSS CENTRAL WISCONSIN AND IS MAINLY UNIDIRECTIONAL
SO STORM MODE SHOULD MAINLY BE MULTICELL CLUSTERS OR SOME BOWING
SEGMENTS.

.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 324 PM CDT MON APR 29 2013

TUESDAY NIGHT THROUGH THURSDAY

THIS FRONT WILL STALL OUT ACROSS SOUTHERN WISCONSIN AND EASTERN
IOWA INTO TUESDAY NIGHT WITH IT EVENTUALLY WEAKENING TOWARD
WEDNESDAY MORNING. AS THIS OCCURS...THE MAIN MID LEVEL TROUGH WILL
START CARVING OUT ACROSS THE CENTRAL PLAINS WITH A STRONG BAND OF
FRONTOGENESIS ALIGNING FROM NORTH TO SOUTH ACROSS THE UPPER
MISSISSIPPI VALLEY REGION. THIS WILL LEAD TO A PROLONGED PERIOD OF
MODERATE TO HEAVY PRECIPITATION...PARTICULARLY ACROSS SOUTHEAST
MINNESOTA AND NORTHEAST IOWA WEDNESDAY INTO THURSDAY. PRECIPITATION
WILL START OUT AS ALL RAIN ON WEDNESDAY...BUT THEN IS EXPECTED TO
COOL ENOUGH TO CHANGE OVER TO ALL SNOW IN SOUTHEAST MINNESOTA AND
NORTHEAST IOWA LATE WEDNESDAY NIGHT INTO THURSDAY. THE 29.12Z
NAM/GFS AND 29.15Z SREF ALL BACK THIS IDEA...THOUGH THE 29.12Z
ECMWF HAS COME BACK IN AS A WARM OUTLIER AND BRINGS THE MOST
UNCERTAINTY TO THIS FORECAST. THE WARM LAYER THAT THIS RUN OF THE
ECMWF PRODUCES TAKES THE MAIN SNOW BAND FURTHER TO THE WEST AND
OUT OF THE FORECAST AREA. THE CONSENSUS...OUTSIDE OF THE
ECMWF...WAS TO KEEP THE PRECIPITATION TYPE AS MAINLY SNOW ACROSS
SOUTHEAST MINNESOTA AND PORTIONS OF NORTH CENTRAL/EAST IOWA LATE
WEDNESDAY NIGHT INTO THURSDAY. SNOWFALL AMOUNTS ARE CURRENTLY
FORECAST TO MAINLY BE IN THE 2 TO 4 INCH RANGE...WITH A FEW SPOTS
THAT END UP UNDER THE MAIN BAND POTENTIALLY HITTING 6 INCHES OR
HIGHER. BECAUSE OF THE ECMWF...CONFIDENCE IS NOT HIGH ENOUGH YET
TO PUT OUT A WINTER STORM WATCH...BUT LATER SHIFTS WILL HAVE TO
WATCH FOR TRENDS ON THIS BAND AND WHERE IT ENDS UP.

THURSDAY NIGHT THROUGH MONDAY

THIS PERIOD IS CHARACTERIZED BY LOW CONFIDENCE AS THE LARGE CLOSED
LOW OVER THE CENTRAL U.S. IS STILL PRODUCING GREAT SPREAD WITHIN THE
NUMERICAL GUIDANCE. THESE ARE TRADITIONALLY HIGH SPREAD SITUATIONS
FOR THE MODELS. THUS...USED THE CONSENSUS BLEND AS IS FOR THE
PERIOD.

THE BIG PICTURE FOR THIS THE PERIOD BEGINS WITH THE STRONG
FRONTOGENESIS OVER THE FORECAST AREA WEAKENING WITH TIME AND WARMING
BEGINNING. THIS WARMING IS GENERALLY AGREED ON...WHICH WOULD CHANGE
ANY SNOW TO RAIN BY SATURDAY. THE LATEST 28.12Z ECMWF SUGGESTS A
WARMER SOLUTION TO THE ENTIRE PERIOD WITH ALL RAIN...EVEN IN WESTERN
MOST PART OF THE FORECAST AREA.

AS THE UPPER LOW SHIFTS EAST/NORTHEAST...A SURFACE LOW DEEPENS AND
ROTATES NORTH-NORTHWEST AND ELICITS HEAVY RAINFALL AHEAD OF IT ON
THE EAST SIDE OF THE UPPER LOW IN A RICH...OPEN GULF OF MEXICO FLOW.
THUS...SOME AREAS WILL SEE 1-2 INCHES OF RAIN INTO THE EARLY
WEEKEND...BUT THE BIG PROBLEM IS...WHERE. THE MODEL SPREAD WITH THIS
RAINFALL IS FROM KANSAS CITY MO /28.12Z GEM AND GFS/ TO THE LOCAL
AREA /28.12Z ECMWF/. IF THE EARLY PORTION OF THE FRONTOGENESIS
PRECIPITATION ON WED-THU IS ALL RAIN...THERE COULD BE 4 INCHES OF
RAINFALL THIS WEEK BY SUNDAY. THE HIGHEST CONFIDENCE OF THIS
OCCURRING LOOKS TO BE NEAR I-35 JUST EAST OF ANY SNOW BAND THAT
FORMS. THIS WOULD PROBABLY INCLUDE PARTS OF THE WESTERN FORECAST
AREA. BUT...THIS AGAIN IS LOW CONFIDENCE. IT SEEMS THE PATTERN SAYS
IT WILL HAPPEN BUT THE LOCATION IS A TOUGH CALL RIGHT NOW.

FOR THE SUNDAY AND MONDAY PERIOD...THE LOW SHOULD HAVE LESS AND LESS
IMPACT WITH WARMING TEMPERATURES AND MORE SCATTERED SHOWERY WEATHER.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1145 PM CDT MON APR 29 2013

SUMMARY...VFR CONDITIONS ARE EXPECTED THROUGH THIS EVENING WITH
BREEZY SOUTH TO SOUTHWEST WINDS DROPPING DOWN TO THE SURFACE
DURING THE MORNING.

DETAILS...
SHOWERS AND THUNDERSTORMS HAVE FORMED OVER CENTRAL IOWA ALONG A
WARM FRONT AS EXPECTED. MODEL GUIDANCE AS WELL AS EXTRAPOLATION
WOULD SUGGEST THESE STAY SOUTHEAST OF THE TAF SITES FOR THE
MORNING HOURS...THOUGH KLSE COULD GET BRUSHED. AS A RESULT...HAVE
MAINTAINED THAT VCSH FOR 09-14Z. ADDITIONALLY...A 40-50 KT JET
BETWEEN 1500-2000 FT AGL IS PRESENT AS SEEN ON RADAR VAD WIND
PROFILE DATA OVER THE TAF SITES. WITH SOUTHEAST WINDS AT THE
SURFACE BEING NORTH OF THE WARM FRONT...LOW LEVEL WIND SHEAR IS
OCCURRING. THIS LOW LEVEL WIND SHEAR LOOKS TO PERSIST UNTIL A FEW
HOURS AFTER SUNRISE WHEN MIXING CAN TRANSPORT SOME OF THIS WIND TO
THE SURFACE AS GUSTS. THESE GUSTS SHOULD REACH 20-30 KT. DURING
THE AFTERNOON...A COLD FRONT IS PROGGED TO MOVE THROUGH THE TAF
SITES...AROUND 19Z AT KRST AND 23-00Z AT KLSE. THIS FRONT WILL
HELP DIMINISH THE GUSTS AND EVENTUALLY SWING WINDS AROUND TO THE
NORTHWEST. UNCERTAINTY REMAINS IF ANY STORMS CAN FIRE ON THIS
FRONT. IF THEY DO...KLSE WOULD BE THE SITE MORE LIKELY TO BE
IMPACTED. BETTER CHANCE FOR RAIN...FOR BOTH TAF SITES...LOOKS TO
OCCUR AFTER THE FRONT PASSES...BEGINNING AROUND 02Z. CEILINGS AND
VISIBILITIES APPEAR TO STAY VFR... THOUGH. THERE COULD BE SOME
THUNDER ACCOMPANYING THE SHOWERS...BUT THE COVERAGE RIGHT NOW
SEEMS ISOLATED AT BEST AND THUS CONFIDENCE IS TOO LOW TO MENTION.

&&

.HYDROLOGY...
ISSUED AT 324 PM CDT MON APR 29 2013

HEAVY PRECIPITATION RATES ARE EXPECTED WEDNESDAY INTO FRIDAY AS A
STORM SYSTEM STALLS ACROSS THE REGION. IF THE PRECIPITATION FALLS
MAINLY AS RAIN...THERE IS THE POTENTIAL FOR 1 TO 3 INCHES TO FALL
BY FRIDAY...PARTICULARLY IN SOUTHEAST MINNESOTA AND NORTHEAST
IOWA. THIS ADDITIONAL RAINFALL WILL LEAD TO SOME RISES ON LOCAL
RIVERS AND STREAMS WHICH ARE ALREADY SOME WHAT HIGH DUE TO RECENT
PRECIPITATION AND THE SPRING SNOW MELT. CONFIDENCE IS NOT VERY
HIGH AT THIS POINT WITH WHERE THIS MAIN BAND WILL SET UP OR IF IT
WILL END UP AS SNOW...BUT THE GENERAL AREA THAT APPEARS TO TAKE
THE BRUNT OF THIS SYSTEM IS SOUTHEAST MINNESOTA AND NORTHEAST IOWA.

&&

.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&

$$

SHORT TERM...HALBACH
LONG TERM...HALBACH/BAUMGARDT
AVIATION...AJ
HYDROLOGY...HALBACH







AREA FORECAST DISCUSSION

NWS MILWAUKEE/SULLIVAN WI

 1112 PM CDT MON APR 29 2013

.UPDATE...
CONVECTION HAS DISSIPATED AS IT RAN OUT OF SFC BASED CAPE. HOWEVER
ELEVATED CAPE OF 500-1000 J/KG AND LOW TO MID LEVEL WARM...MOIST
ADVECTION REMAINS OVER MUCH OF SRN WI AS A 50 KT SLY LLJ IS
ONGOING OVER THE AREA. THEREFORE...ELEVATED CONVECTION WILL REMAIN
A POSSIBILITY LATE THIS EVENING INTO THE OVERNIGHT. MORE
WIDESPREAD SHOWERS AND TSTORMS ARE EXPECTED AFTER 09Z FOR THE WRN
AND NRN CWA AS CONVECTION OVER CENTRAL IA ORGANIZES INTO A MCS.
THIS CONVECTION IS ASSOCIATED WITH WARM...MOIST ADVECTION ON A
SEPARATE 60 KT LLJ THAT WILL MOVE FROM KS TO IA TO CNTRL/SRN WI
FOR TUE AM. CONVECTION TO END BY MID MORNING WITH A VERY
WARM...WINDY AND CAPPED WARM SECTOR EXPECTED FOR MUCH OF THE DAY.
HIGH TEMPS INTO THE MID 80S ARE POSSIBLE. A COLD FRONT WILL THEN
STALL NW OF MADISON WITH SHOWERS AND TSTORMS EXPECTED THERE LATE
TUE AFTERNOON AND NIGHT.


&&

.AVIATION/06Z TAFS/...ONLY VERY SMALL CHANCES OF SHOWERS OR
TSTORMS LATE THIS EVENING INTO THE EARLY MORNING HOURS. SHOWERS
AND TSTORMS WILL THEN ARRIVE OVER KMSN AROUND 09Z-10Z AND LAST 2-4 HOURS.
MORE UNCERTAINTY FOR THE SE WI TAF SITES AS THE MAIN AREA OF
TSTORMS MAY MISS THEM TO THE NORTH. THREAT OF TSTORMS TO THEN END
BY MID MORNING WITH A CAPPED ATMOSPHERE INTO TUE EVENING FOR THE
SE WI TAF SITES. KMSN WILL HAVE CHANCES OF TSTORMS TUE NIGHT BUT
WITH MUCH BETTER CHANCES TO THEIR NW WHERE THE COLD FRONT STALLS.
VFR CONDITIONS TO PREVAIL EXCEPT IN TSTORMS.


&&

.PREV DISCUSSION... /ISSUED 420 PM CDT MON APR 29 2013/

VERY SHORT TERM...TONIGHT AND TUESDAY. FORECAST CONFIDENCE IS
MEDIUM.

LINE OF ELEVATED SHOWERS AND A FEW THUNDERSTORMS SHIFTING EAST
NORTHEAST THROUGH THE AREA AT THIS TIME...BEING FED BY SOUTH
SOUTHWESTERLY 850MB LOW LEVEL JET NOSE. THESE SHOULD CONTINUE TO
MOVE THROUGH THE REMAINDER OF THE AREA LATE THIS AFTERNOON.

SOUTHWESTERLY 850MB LOW LEVEL JET NOSE WILL CONTINUE TO POINT INTO
THE AREA TONIGHT...GRADUALLY INCREASING IN MAGNITUDE. WARM AIR
ADVECTION KICKS IN TONIGHT AS WELL. TAIL END OF 500MB VORTICITY
MAXIMUM OVER SOUTHERN MINNESOTA WILL SHIFT CLIP THE NORTHERN
PORTIONS OF THE AREA THROUGH EARLY EVENING...WITH ANOTHER OVER
EASTERN NEBRASKA SHIFTING INTO THE AREA BY 06Z TUESDAY.

ADJUSTING AREA FORECAST SOUNDINGS FOR LOWER TO MID 50S DEW POINTS
YIELD MEAN LAYER CAPES OF UP TO 500 J/KG INTO EARLY EVENING...THEN
SHOW ELEVATED CAPES INCREASING TONIGHT OVER 1000 J/KG. THIS IS IN
RESPONSE TO MOISTURE BUILDING IN THE 925MB TO 850MB LEVEL. DEEP
LAYER SHEAR IS STRONG INTO EARLY EVENING...THEN WEAKENS SOMEWHAT
LATER TONIGHT AS MID LEVEL WINDS WEAKEN. SPC HAS SLIGHT RISK AREA
INTO JUST THE FAR SOUTHWESTERN SECTIONS OF THE AREA. MAIN RISK
APPEARS TO BE IN IOWA...THOUGH IF HIGHER DEW POINTS MOVE IN AND
INCREASE CAPE THIS EVENING...COULD SEE A SEVERE STORM OR TWO OCCUR.

4KM WRF/NMM MODEL SHOWING SPOTTY SHOWERS AND A FEW STORMS THIS
EVENING...WITH A MORE ORGANIZED AREA OF SHOWERS AND STORMS FOR LATER
TONIGHT WITH LOW LEVEL JET FORCING. HRRR KEEPING BULK OF CONVECTION
JUST SOUTH AND SOUTHWEST OF THE AREA TONIGHT. FOR NOW...WILL GO WITH
SCATTERED SHOWERS AND ISOLATED STORMS EARLY THIS EVENING...WITH
THUNDER FOR LATER THIS EVENING AND OVERNIGHT.

MODELS SHOWING WARM SECTOR AIRMASS MOVING INTO THE AREA
TUESDAY...CAPPING OFF THE AREA FROM PRECIPITATION. GUSTY
SOUTH/SOUTHWEST WINDS AND EXPECTED 925MB TEMPERATURES SHOULD BRING
HIGHS INTO THE LOWER 80S IN MOST AREAS. COOLER VALUES NEAR SHEBOYGAN
WITH SOUTH ONSHORE WINDS. APPROACHING COLD FRONT LATER IN THE
AFTERNOON SHOULD BRING INCREASED CHANCES FOR THUNDERSTORMS...THOUGH
BEST SHOT IS INTO TUESDAY NIGHT.

SHORT TERM...TUESDAY NIGHT THROUGH THURSDAY.

TUESDAY NIGHT AND WEDNESDAY...FORECAST CONFIDENCE LOW TO MEDIUM.

THUNDERSTORMS ALONG AND AHEAD OF THE FRONTAL BOUNDARY ONGOING AT THE
BEGINNING OF THE PERIOD EXPECTED TO TRANSITION TO MAINLY RAIN
SHOWERS FROM NORTHWEST TO SOUTHEAST BEHIND THE FRONT ON WEDNESDAY AS
IT SAGS THROUGH THE FORECAST AREA. THOUGH SURFACE FRONT MAKES IT TO
OR NEAR SE WI BY 12Z WED...UPPER TROUGH STILL WELL TO THE WEST AND
WILL KEEP THE FOCUS FOR PRECIPITATION THROUGH IOWA INTO WESTERN WI.
WILL KEEP CHANCE POPS ALONG THE FRONT.

LOWS WILL NOT FALL OFF MUCH TUESDAY NIGHT UNTIL LATE IN THE
NW...THEN WARM SE WEDNESDAY AHEAD OF STALLED BAROCLINIC ZONE
BISECTING THE CWA...THOUGH COOLER ALONG THE LAKE.

WEDNESDAY NIGHT AND THURSDAY...FORECAST CONFIDENCE MEDIUM.

LIKELY POPS INTO THE WESTERN CWA WITH INCREASING FORCING AHEAD OF
SLOWLY APPROACHING TROUGH AS IT DEEPENS OVER THE CENTRAL U.S.
MODELS STILL DIFFER WITH THE PLACEMENT OF BAROCLINIC ZONE WHICH
AFFECTS NOT ONLY TEMPERATURES BUT LOCATION OF BETTER LOW TO MID
LEVEL FRONTOGENESIS AND Q-VECTOR CONVERGENCE.

BLENDED SOLUTION KEEPS LIKELY POPS OVER SOUTH CENTRAL WI THROUGH THE
DAY THURSDAY...THEN SHIFT ACROSS THE ENTIRE CWA THURSDAY NIGHT.
THERMAL RIDGE NOSING INTO THE FAR SOUTH WILL BRING HIGHS IN THE
UPPER 50S THERE...THEN TAPER OFF TO THE MID 40S NW WITH UPPER 40S
ALONG THE LAKE.

LONG TERM...THURSDAY NIGHT THROUGH MONDAY. FORECAST CONFIDENCE...
LOW.

MODELS STILL TRYING TO GET A HANDLE ON LOW CUTTING-OFF OVER THE
CENTRAL PLAINS THURSDAY NIGHT AND THEN LIFTING SLOWLY NWD INTO THE
UPPER MIDWEST SUNDAY. SOME THERMAL DIFFERENCES THAT MAY IMPACT
PRECIPITATION TYPE AND BRING SOME SNOWFLAKES MIXING IN WITH THE RAIN
IN THE FAR WEST/NW LATE THURSDAY NIGHT...BUT WILL LEAVE ALL LIQUID
FOR NOW. OTHERWISE A CLOUDY...COOL AND WET PERIOD THROUGH THE
WEEKEND WITH TEMPERATURES STRUGGLING INTO THE LOWER 50S...COOLER BY
THE LAKE WITH GENERALLY EASTERLY FLOW. PERIODS OF RAIN...WITH
INTENSITY DEPENDENT ON STRENGTH OF VORTICITY MAXIMA ROTATING THROUGH
THE REGION AND THE AMOUNT OF AVAILABLE MOISTURE WITH STREAMERS OF
DRIER AIR WRAPPING AROUND CIRCULATION. SOME HOPE THAT THE LOW WILL
LIFT FAR ENOUGH AWAY BY MONDAY TO LOWER RAIN CHANCES AND ALLOW
WARMER TEMPS.

AVIATION/00Z TAFS/...

VFR CONDITIONS ARE EXPECTED THIS EVENING ACROSS TAF SITES. SCATTERED
SHOWERS AND A FEW THUNDERSTORMS MOVING THROUGH AT THIS TIME...WITH
MORE AT TIMES MAINLY LATER TONIGHT INTO EARLY TUESDAY MORNING. THERE
WILL BE LULLS IN THE PRECIPITATION.

FOR NOW...WILL KEEP VICINITY THUNDER WORDING IN TAFS...AS THERE IS
SOME UNCERTAINTY WITH THE EXACT TIMING AND AREAL COVERAGE OF THE
SHOWERS AND STORMS. ANY STORMS WOULD BRING VISIBILITIES DOWN TO
NEAR ALTERNATE MINIMUMS...WITH MVFR CEILINGS.

SOUTH WINDS TONIGHT WILL GRADUALLY INCREASE AND SHIFT SOUTHWEST BY
TUESDAY AFTERNOON. GUSTS TO 25 KNOTS OR SO ARE EXPECTED BY TUESDAY
AFTERNOON.

MARINE...

A TIGHT PRESSURE GRADIENT WILL DEVELOP OVER THE NEARSHORE WATERS
TUESDAY...WHICH WILL RESULT IN GUSTY SOUTH WINDS. FREQUENT GUSTS TO
25 KNOTS ARE EXPECTED. THUS...A SMALL CRAFT ADVISORY WILL BE ISSUED
FROM MID MORNING THROUGH EARLY EVENING TUESDAY.

ANOTHER TIGHT PRESSURE GRADIENT WILL DEVELOP WITH THE INFLUX OF
COLDER AIR FOR WEDNESDAY NIGHT THROUGH THURSDAY NIGHT. THIS WILL
BRING BRISK AND GUSTY NORTH TO NORTHEAST WINDS DURING THIS
TIME...ALONG WITH HIGH WAVES. A SMALL CRAFT ADVISORY MAY BE NEEDED
DURING THIS TIME.

&&

.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...SMALL CRAFT ADVISORY FROM 10 AM TO 7 PM CDT TUESDAY FOR
     LMZ643>646.

&&

$$

UPDATE...GEHRING
TONIGHT/TUESDAY AND AVIATION/MARINE...WOOD
TUESDAY NIGHT THROUGH MONDAY...REM







AREA FORECAST DISCUSSION

NWS MELBOURNE FL

 1035 AM EDT TUE APR 30 2013

.DISCUSSION...
MORNING SOUNDINGS SHOW A NEARLY SATURATED AIRMASS WITH SWRLY FLOW
THRU THE H100-H70 LYR...SLIGHTLY DRIER WITH WRLY FLOW ABV H70.
KTBW/KMFL PWAT VALUES BTWN 1.6"-1.7" WITH H50 TEMPS BTWN -10C AND
-12C. RUC ANALYSIS SHOWING A WEAK SPOT LOW IN THE H100-H85 WIND
FIELD OFF THE NE FL COAST. GENTLE S/SWRLY FLOW PREVAILS OVER THE S
HALF OF THE FL PENINSULA BCMG LIGHT WRLY FLOW OVER THE N HALF...
CONVERGENCE ZONE EXTENDING FROM LAKE OKEECHOBEE TO TAMPA BAY.
MOISTURE IS PLENTIFUL WITH H10-H70 MEAN RH VALUES BTWN 80-90PCT AND
SFC DEWPOINTS IN THE M/U60S.

ALOFT...DYNAMIC SUPPORT IS NOT ALL THAT IMPRESSIVE...LITTLE IN THE
WAY OF UPSTREAM MID LVL VORTICITY OR UPR LVL DIVERGENCE. HOWEVER...
MID LVL OMEGA FIELDS ARE STRONGLY NEGATIVE OVER THE S FL
PENINSULA...INDICATING UPWARD VERTICAL MOTION.

AIRMASS IS PRIMED FOR ANOTHER ROUND OF CONVECTION...ABOUT THE ONLY
THING MISSING ACRS THE NRN CWA AT THIS POINT IS SFC HEATING DUE TO
MID/UPR LVL DEBRIS CLOUDS GENERATED BY EARLIER CONVECTION OVER THE W
FL PENINSULA. INDEED...CONVECTION HAS ALREADY FIRED ARND LAKE
OKEECHOBEE WHERE DEBRIS CLOUDS ARE THIN. NOT COINCIDENTALLY...THIS
IS ALSO WHERE THE OMEGA FIELD INDICATES THE STRONGEST LIFT.

LATEST SAT PICS SHOW THE DEBRIS DECK STEADILY ERODING FROM THE WEST
WITH THE CLEARING LINE PUSHING E OF I-75. WEAK WIND FIELDS SHOULD
ALLOW BOTH THE EAST AND WEST COAST SEABREEZES TO DEVELOP ONCE SFC
HEATING SETS IN. ANTICIPATE STORM INITIALIZATION ACRS THE
CENTRAL/NRN CWA BY EARLY AFTN. STRONG CONVECTION PSBL DUE TO COLD
TEMPS ALOFT... ESPECIALLY WHERE MESOSCALE BOUNDARY COLLISIONS OCCUR.

&&

.AVIATION....
THRU 30/18Z...PREVAILING CIGS BTWN FL100-120...LCL MVFR VSBYS/CIGS
IN BRIEF SHRAS S OF KMLB-KISM. AFT 30/18Z...PREVAILING CIGS BTWN
FL080-100...NMRS MVFR SHRAS AND SCT IFR TSRAS ALL SITES CONTG THRU
01/02Z INTERIOR...01/04Z COASTAL...ISOLD +TSRA WITH SFC WND G35KTS
PSBL BTWN 30/19Z-30/23Z.

&&

.MARINE...
OBS FROM THE DATA BUOY/C-MAN NETWORK MEASURING W/SWRLY WINDS AOB
10KTS...SEAS ARND 4FT ALMOST ALL OF WHICH IS DUE TO A 13-14SEC
SWELL. PGRAD FAIRLY TIGHT TO THE SE. HOWEVER...AN INVERTED SFC TROF
CENTERED OFF THE CAROLINA COAST WILL KEEP THE LCL WIND FIELD WEAK
AND DISORGANIZED. LITTLE PROSPECT FOR STRONG WINDS OUTSIDE OF LCL
CONVECTION. WILL REMOVE THE CAUTIONARY STATEMENT WITH THE MORNING
UPDATE...NO OTHER CHANGES NECESSARY.

&&

.MLB WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.

&&

$$

SHORT TERM/AVIATION...BRAGAW
LONG TERM/IMPACT WX...PENDERGRAST






AREA FORECAST DISCUSSION

NWS DETROIT/PONTIAC MI

 1029 AM EDT TUE APR 30 2013

.UPDATE...

NWP MODELS CONTINUE TO HAVE ABSOLUTELY NO CLUE WITH REGARDS TO THE
ONGOING PRECIPITATION OVER THE WESTERN CWA. THESE MODELS ARE
COMPLETELY DRY...EVEN WITH THE 12Z CYCLE...WHICH AS RADAR AND
METAR REPORTS SHOW COULD NOT BE FURTHER FROM THE TRUTH. THE ONLY
MODEL THAT HAS ANY IDEA WHAT IS HAPPENING WITH THIS THETA-E DRIVEN
CONVECTION IS THE LOCAL HRRR MODEL WHICH PUSHES THESE RAIN SHOWERS
THROUGH THE CWA DURING THE EARLY AFTERNOON HOURS. THEREFORE WILL
RAISE POPS SIGNIFICANTLY INTO THE CATEGORICAL RANGE AS THIS
ACTIVITY SWEEPS THROUGH THE CWA THIS AFTERNOON.

WITH THIS ACTIVITY AND ABUNDANT CLOUD COVER HIGH TEMPERATURES WILL
SURELY NOT GET CLOSE TO 80 AS PREVIOUSLY ADVERTISED. WHILE THERE
IS STILL HOPE THE LATE APRIL SUN ANGLE WILL BE ABLE TO BOOST
TEMPERATURES BEHIND THESE SHOWERS...WILL TAKE A GOOD 5 TO 10 DEGREES
OFF PREVIOUS HIGH TEMPERATURES AS A FIRST SLICE AT HIGH
TEMPERATURES THIS AFTERNOON.

&&

.AVIATION...ISSUED 723 AM EDT TUE APR 30 2013

//DISCUSSION...

CONVECTION HAS FLARED UP VIGOROUSLY ALONG THE LEADING EDGE OF THE
MID LEVEL MOISTURE AXIS ASSOCIATED WITH A WARM FRONT THAT WILL MOVE
THROUGH LOWER MICHIGAN TODAY. EARLIER TERMINAL UPDATES REFLECT THE
INCREASED COVERAGE AND INTENSITY OF THE STORMS WITH A SHORT PERIOD
OF MVFR/IFR CONDITIONS AND PERHAPS A SOUTHWEST WIND GUST AS THE MAIN
CLUSTER MOVES THROUGH THE REGION. EXPECT THE STORMS TO BE NORTH AND
EAST OF THE TERMINAL SITES BY ABOUT NOON FOLLOWED BY WARM SECTOR
CHARACTER OF VFR CONDITIONS WITH GUSTY SOUTH WIND UNTIL SUNSET.
AVIATION CONDITIONS WILL REMAIN FAVORABLE TONIGHT WITH LIGHT WIND
BUT LIKELY NOT ENOUGH TO AVOID A SHORT PERIOD OF MVFR FOG AROUND
SUNRISE WEDNESDAY MORNING.

FOR DTW... THERE IS SOME POTENTIAL FOR THE SOUTH END OF CONVECTIVE
LINE TO BECOME MORE SOLID AS STORMS APPROACH DTW BUT THE
WIDTH/DURATION WILL REMAIN RELATIVELY SHORT. ALL STORM ACTIVITY WILL
BE EAST OF THE AIRPORT BY NOON OR SHORTLY AFTER.

//DTW THRESHOLD THREATS...

* HIGH CONFIDENCE IN THUNDERSTORM COVERAGE AND TIMING DURING THE
  MORNING.

&&

.PREV DISCUSSION...ISSUED 359 AM EDT TUE APR 30 2013

SHORT TERM... TODAY AND TONIGHT

A WARM FRONT WILL MOVE FROM THE MIDWEST THROUGH LOWER MICHIGAN TODAY
AS LOW PRESSURE MOVES FROM THE NORTHERN PLAINS INTO NORTHERN
ONTARIO. THE FRONT WILL FIRST PRESENT CLOUDS, A CHANCE OF SHOWERS,
AND POSSIBLY A THUNDERSTORM DURING THE MORNING BEFORE PASSING NORTH
AND OPENING THE DOOR ON WARM TEMPERATURES DURING THE AFTERNOON
THROUGH TONIGHT.

EARLY MORNING SURFACE ANALYSIS INDICATES THE WARM FRONT IS SOMEWHAT
DIFFUSE BUT MODEL ANALYSIS FIELDS INDICATE A WELL DEFINED THETA-E
AXIS IN THE 850 TO 700 MB LAYER FEATURING 850 MB DEWPOINT AROUND 10C
THAT MATCHES UP WELL WITH UPSTREAM 00Z SOUNDINGS. THERE IS ALSO A
SHARP LEADING MOISTURE GRADIENT WHICH IS PROJECTED THROUGH LOWER
MICHIGAN DURING THE MORNING. THE ASSOCIATED SYSTEM RELATIVE
ISENTROPIC ASCENT AND MOISTURE ADVECTION IS EXPECTED TO BE A
DESTABILIZING PROCESS OVER OUR AREA THROUGH THE REST OF THE MORNING.
SPC MESOANALYSIS INDICATES MID LEVEL LAPSE RATES OF 7-8C/KM
AVAILABLE FROM UPSTREAM CENTERED OVER EASTERN IOWA WHICH WILL TEND
TO SPREAD OVER LOWER MICHIGAN BY ABOUT SUNRISE. IT IS THEN
REASONABLE TO EXPECT DEVELOPMENT OF CHANCE/SCATTERED COVERAGE OF
SHOWERS AND THUNDERSTORMS OVER THE ENTIRE AREA AS A STARTING POINT
WITH AN UPDATE TO GREATER COVERAGE AS RADAR TRENDS DICTATE
REFINEMENT ON LOCATION.

THE PASSAGE OF THE WARM FRONT BY EARLY AFTERNOON WILL THEN BRING THE
WARM SECTOR OF THE LARGER SCALE PATTERN OVER OUR AREA. MODEL
SOUNDINGS INDICATE THE MIXED LAYER WILL REMAIN RELATIVELY SHALLOW,
ONLY UP TO ABOUT 875 MB, IN SUPPORT OF MAX TEMPS IN THE MID TO UPPER
70S MOST LOCATIONS. MODEL SURFACE STREAMLINES ORIGINATE MORE FROM
THE OHIO VALLEY THROUGH THE DAY SO AN INTERIOR MAX OF 80 WILL BE AT
THE TOP OF THE RANGE. MORE IMPORTANT IS THE SLIGHT ONSHORE WIND
COMPONENT THAT WILL KEEP READINGS COOLER NEAR THE LAKE HURON
SHORELINE AND LAKE ST CLAIR/ERIE AGGREGATE. THIS SAME TENDENCY IN
THE WIND WILL THEN BACK EVEN MORE TOWARD THE SOUTHEAST WITH SOME
DECOUPLING TONIGHT. THIS WILL ALLOW MIN TEMPS TO SETTLE DOWN INTO
THE 50S WITH DRY CONDITIONS AND PARTLY CLOUD SKY THROUGH SUNRISE
WEDNESDAY.

LONG TERM...WEDNESDAY THROUGH MONDAY.

WEDNESDAY...A DIGGING TROUGH INTO COLORADO AND ANTICYCLONICALLY
CURVED JET STREAK EJECTING NORTHWARD THROUGH CANADA WILL FORCE
AGGRESSIVE DOWNSTREAM AMPLIFICATION OF THE EASTERN NOAM UPPER LEVEL
RIDGE. 500MB VORTICITY FIELD IS SUGGESTIVE THAT DEEP COLUMN
SUBSIDENCE WILL BE IN PLACE OVER THE CENTRAL GREAT LAKES...WITH A
SHARP EASTERN GRADIENT TO THE PRECIPITATION OVER PORTIONS OF
WISCONSIN/IOWA. CLOSED HEIGHT CONTOURS AT 500MB ARE SHOWN TO SNEAK
INTO SOUTHEASTERN MICHIGAN WEDNESDAY AFTERNOON. THE GOOD CONNECTION
OF REMNANT ELEVATED MIXED LAYER WILL STILL EXIST FOR WEDNESDAY
AFTERNOON...SUPPORTING THE WARMEST TEMPERATURES OF THIS STRETCH. LOW
80 APPEARS A GOOD FORECAST FOR THE TRI CITIES WITH MID TO UPPER 70S
ELSEWHERE.

THE ANTICYCLONIC INFLECTION/BUBBLE IN JET IS EXPECTED TO WORK
THROUGH THE REGION LATE WEDNESDAY NIGHT AND THURSDAY. THIS FEATURE
SHOULD SUPPORT AN ADDITIONAL SHORTWAVE RIDGE COMPONENT. NCEP MODELS
ARE VERY SUSPECT WITH QPF SNEAKING ONTO THE WESTERN FRINGES OF THE
CWA...PRIMARILY IN THE LEE OF LAKE MICHIGAN. PRECIPITATION SHOULD
REMAIN IN THE COLD SECTOR...BUT BREAKS OUT CONVECTION IN A SECONDARY
ZONE WELL AHEAD OF MAIN STATIONARY BAROCLINIC ZONE. THE PROBLEM IS
THIS DOESN/T HAVE THE LOOK OF A WEATHER SYSTEM THAT WOULD FORCE
PREFRONTAL TROUGH CONVECTION. THE BELIEF IS THERE ARE LIKELY SURFACE
MOISTURE PARAMETRIZATION ISSUES WHICH IS SOME CAUSE TO THE NOISY
SOLUTIONS. THE FORECAST IS ALREADY SIDING IN A DRY FASHION...AND DID
NOT SEE ANYTHING IN THE NEW NWP TO SUGGEST OTHERWISE.
UNFORTUNATELY...THIS IS A BINARY ALL OR NOTHING TYPE FORECAST WITH A
CONSIDERABLE AMOUNT OF BUST POTENTIAL IF PRECIPITATION MOVES IN. THE
AIRMASS IN PLACE WILL HAVE UNDERGONE SOME HOMOGENIZATION BY
THURSDAY. THEREFORE...HIGHS ARE GENERALLY 3 TO 4 DEGREES COOLER THAN
THE PRECEDING DAY.

MODELS THEN DIVERGE CONSIDERABLY FOR THIS WEEKEND. THE FAVORED ECMWF
SHOWS A CONSIDERABLE CUTOFF EVENT OVER THE CENTRAL PART OF THE
COUNTRY BY FRIDAY. THE UPSTREAM RESPONSE IS TO FORM A POSITIVE
HEIGHT ANOMALY COUPLET TO THE NORTHEAST OF THE CLOSED LOW. THE ECMWF
SUGGESTS THE CENTER OF THE ANOMALY WILL MEANDER...BUT SHOULD
MAINTAIN A FIRM GRASP OF LOWER MICHIGAN THROUGH SATURDAY. THE
FORECAST IS SIDED THERE...AND WILL GO DRY THROUGH THE FIRST HALF OF
THE WEEKEND. DO NOT FEEL PARTICULARLY GOOD ABOUT THE MAX T FORECAST
THIS WEEKEND AS THERE IS PLENTY OF COLD/PRECIPITATION/CLIMO BIASED
SOLUTIONS FACTORING IN THE OFFERED GUIDANCE. WILL GIVE IT SOME TIME
BEFORE GETTING MORE AGGRESSIVE WITH THE WEEKEND TEMPERATURES.

MARINE...

LOW PRESSURE MOVING FROM NORTHERN MINNESOTA INTO NORTHERN ONTARIO
TODAY WILL BOOST SOUTHERLY WIND OVER THE OPEN WATERS OF LAKE HURON,
BUT WARM AIR MOVING OVER THE COLD WATER WILL PROVIDE VERY HIGH
STABILITY. THIS WILL KEEP WAVE ACTION SUBDUED THROUGH TONIGHT. AFTER
THAT, THE TRAILING COLD FRONT WILL SETTLE CLOSE ENOUGH TO THE
STRAITS FOR LIGHTER WIND OVER ALL MARINE AREAS. FAVORABLE MARINE
CONDITIONS ARE THEN ANTICIPATED THROUGH THE REST OF THE WEEK AS THE
FRONT IS PROJECTED TO STALL OVER THE WESTERN GREAT LAKES.

&&

.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MI WATERS OF LAKE ERIE...NONE.

&&

$$

UPDATE.......KURIMSKI
AVIATION.....BT
SHORT TERM...BT
LONG TERM....CB
MARINE.......BT


YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).







AREA FORECAST DISCUSSION

NWS MARQUETTE MI

 800 AM EDT TUE APR 30 2013

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 516 AM EDT TUE APR 30 2013

WV IMAGERY AND RUC ANALYSIS INDICATED A BROAD MID/UPPER LEVEL TROUGH
OVER THE NW CONUS RESULTING IN SW FLOW FROM THE CNTRL PLAINS TO THE
NRN GREAT LAKES. A VIGOROUS SHORTWAVE TROUGH WAS LCOATED OVER THE SE
CORNER OF SASK INTO FAR NW ND.  AT THE SFC...LOW PRES WAS LOCATED
OVER NE SOUTH DAKOTA WITH A WARM FRONT THROUGH SE MN INTO SRN WI. A
LLJ AHEAD OF THE WITH INFLOW OF MOIST/UNSTABLE AIR SUPPORTED TSRA
INTO SRN WI AND CNTRL LAKE MI. ISOLD SHOWERS NEAR ESC-ISQ HAD
DIMINISHED AS THE STRONGER CONVECTION DEVELOPED TO THE SOUTH.
UPSTREAM...A WEAK SHRTWV AHEAD OF THE LOW  SUPPORTED A BAND OF
SHRA/TSRA OVER NRN MN.

RADAR AND SATELLITE TRENDS SUGGEST THAT MOST OF THE CONVECTION OVER
WI WILL SLIDE JUST SOUTH OF THE CWA BUT MAY EXPAND JUST ENOUGH FOR
SOME SCT SHRA/TSRA...MAINLY SOUTH OF A LINE FROM IMT-ERY. AS THE SD
LOW LIFTS NORTHEAST THROUGH THROUGH NW MN TO NW ONTARIO...WAA AND
MOISTURE ADVECTION WILL INCREASE WITH THE STRENGTHENING SRLY FLOW.
TEMPS CLIMBING INTO THE LOWER TO MID 70S COMBINED WITH DEWPOINTS IN
THE LOWER TO MID 50S WILL RESULT IN MLCAPE VALUES IN THE 600-1200
J/KG RANGE BY THIS AFTERNOON. THE COLD FRONT DRAPED TO THE SOUTH OF
THE LOW MOVING INTO THE WEST UPPER MI THIS AFTERNOON WILL BE THE
MAIN FOCUS FOR SHRA/TSRA DEVELOPMENT. ALTHOUGH THE STRONGEST QVECTOR
CONV WILL BE WELL NORTH OF THE REGION...EVEN MODEST LOW LEVEL CONV
ALONG AND AHEAD OF THE FRONT SHOULD SUPPORT SCT TSRA THIS AFTERNOON
INTO THIS EVENING. SOME STRONGER STORMS MAY BE POSSIBLE WITH 0-6KM
SHEAR VALUES IN THE 40-50 KT...BUT THE GREATER SVR POTENTIAL IS
EXPECTED FARTHER SOUTH(PER SPC) WHERE INSTABILITY WILL BE GREATER.
THE HIGHEST POPS VALUES WERE INCLUDED OVER THE WEST LATE THIS
AFTERNOON AND INTO THE CNTRL AND EAST THIS EVENING...BEFORE
SHRA/TSRA WEAKEN WITH DIURNAL COOLING.

.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 442 AM EDT TUE APR 30 2013

NAM SHOWS A 500 MB RIDGE OVER THE EASTERN U.S. WITH A TROUGH IN THE
NORTHERN AND CENTRAL ROCKIES AND A CLOSED 500 MB LOW OVER THE GULF
COAST 12Z WED. THE TROUGH MOVES INTO THE NORTHERN PLAINS 00Z THU AND
INTO THE UPPER GREAT LAKES ON THU. NAM SHOWING SOME 850-500 MB
Q-VECTOR CONVERGENCE WITH DEEPER MOISTURE OVER THE WEST HALF OF
UPPER MICHIGAN 12Z WED WHICH REMAINS THROUGH 00Z THU. THIS NARROW
RIBBON OF DEEPER MOISTURE REMAINS OVER THE WESTERN CWA THROUGH 12Z
THU BEFORE THIS MOVES AND EXPANDS EASTWARD. GFS AND ECMWF SHOW ABOUT
THE SAME THING AS WELL.

THIS FORECAST PERIOD GETS DOMINATED BY COLDER AIR COMING INTO THE
AREA AND THERE COULD BE A RAIN/SNOW MIX ACROSS THE WESTERN U.P.
STARTING LATE WED NIGHT AND LASTING INTO THU NIGHT. THE WESTERN CWA
ALSO HAS THE BEST MOISTURE AND THEREFORE WILL HAVE THE HIGHEST POPS
WHILE THE EAST IS FURTHER AWAY FROM THE FRONTAL BAND PCPN THAT SETS
UP AND IS IN WARMER AIR AS WELL. QUITE A GRADIENT SETS UP IN
TEMPERATURES WITH THE COLDEST READINGS ACROSS THE WEST AND THE
WARMEST IN THE EAST FOR THROUGH THU. QPF WILL CONTINUE TO BE
HEAVIEST OVER THE WEST WITH ANYWHERE FROM 0.25 INCH ACROSS THE EAST
TO 1.25 IN THE WEST FROM WED TO THU NIGHT. THE COLD AIR DOES NOT
ARRIVE UNTIL LATE WED NIGHT ACROSS THE WEST AND COULD SEE ANYWHERE
FROM 1 TO 6 INCHES WEST OF A LINE FROM BIG BAY TO IRON RIVER FROM
WED NIGHT INTO THU NIGHT. DID RAISE TEMPERATURES A BIT FOR WED WITH
LATER ARRIVAL OF COLDER AIR AND RAISED THEM WED NIGHT AS WELL A
COUPLE DEGREES. OTHERWISE...DID NOT MAKE TOO MANY CHANGES TO THE
GOING FORECAST EXCEPT TO GO A BIT DRIER IN THE EASTERN CWA WHICH IS
FURTHER AWAY FROM THE FRONTAL BAND.

IN THE EXTENDED...GFS AND ECMWF SHOW A 500 MB TROUGH AND CLOSED LOW
OVER THE CENTRAL PLAINS 12Z FRI WITH A RIDGE OVER THE EASTERN U.S.
PATTERN DOES NOT CHANGE MUCH FOR 12Z SAT WITH THE 500 MB RIDGE
REMAINING STATIONARY. THIS 500 MB LOW CONTINUES TO SPIN ACROSS THE
CENTRAL PLAINS 12Z SUN FOR THE ECMWF AND THE GFS IS MUCH FURTHER
SOUTH WITH THE PLACEMENT OF THE 500 MB LOW. GFS CONTINUES TO MOVE
THE LOW EAST WELL SOUTH OF THE AREA 12Z MON WHILE THE ECMWF TAKES
THE LOW AND ASSOCIATED TROUGH THROUGH THE AREA. MANUAL PROGS KIND OF
WASH THIS SYSTEM OUT WITH TIME WITH WEAK SFC PRESSURE PATTERNS. WITH
SLOW CHANGE IN UPPER PATTERN...PERSISTENCE LOOKS TO BE THE WAY TO GO
FOR THIS FORECAST. TEMPERATURES WILL SLOWLY WARM THIS EXTENDED
FORECAST PERIOD FROM BELOW NORMAL TO NEAR NORMAL AND WILL BE WET
WITH PCPN CHANCES ALMOST EACH PERIOD.
&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 800 AM EDT TUE APR 30 2013

A COLD FRONT WILL CROSS UPPER MICHIGAN TODAY BRINGING SCATTERED
SHOWERS THIS AFTERNOON OVER THE WEST AND THIS EVENING OVER CENTRAL
UPPER MICHIGAN. ISOLATED THUNDERSTORMS ARE POSSIBLE...ESPECIALLY AT
KSAW...BUT CONFIDENCE WAS NOT HIGH ENOUGH TO INCLUDE IN THE TAF.
OTHERWISE...WITH THE APPROACHING FRONT AND
HEATING/MIXING...SOUTHERLY WINDS ARE EXPECTED TO BE GUSTING TO NEAR
25KTS TOWARDS THE AFTERNOON HOURS BEFORE SHIFTING TO THE WEST. DRIER
AIR WILL MOVE IN BEHIND THE FRONT WITH VFR CONDITIONS EXPECTED BY
LATE EVENING AND OVERNIGHT.
&&

.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 442 AM EDT TUE APR 30 2013

NO GALES SEEN IN THIS FORECAST PERIOD. WINDS DO GET UP TO 30 KNOTS
ACROSS THE EAST AND NORTH CENTRAL TODAY AS A SFC LOW HEADS
NORTHEAST. WINDS THEN STAY BELOW 25 KNOTS FOR THE REST OF THE
PERIOD.
&&

.HYDROLOGY...
ISSUED AT 543 AM EDT TUE APR 30 2013

UNSEASONABLY WARM AIR AND HIGHER DEWPOINTS WILL CONTINUE TO FAVOR
RAPID MELTING OF THE REMAINING SNOWPACK ACROSS NORTH CENTRAL AND
WEST UPPER MICHIGAN KEEPING RIVER LEVELS HIGH. A COLD FRONT MOVING
THROUGH THIS AFTERNOON INTO TONIGHT MAY PRODUCE ADDITIONAL RAINFALL
OF A QUARTER TO HALF INCH IN SOME LOCATIONS. MUCH COOLER CONDITIONS
EXPECTED FOR REST OF WEEK COMBINED WITH LIMITED SNOWFALL SHOULD LEAD
TO A SLOW FALL IN RIVER LEVELS. ADDITIONAL CHANCES OF RAIN AND
EVEN SNOW OVER THE WEST ARE POSSIBLE WEDNESDAY AFTERNOON INTO
THURSDAY NIGHT...WITH THE HEAVIEST PRECIPITATION OVER THE WESTERN
THIRD OF UPPER MICHIGAN. SO...EVEN THOUGH TEMPERATURES WILL BE
COOLER THIS MAY BE OFFSET BY THE ADDITIONAL PRECIPITATION.

RIVERS OF PARTICULAR CONCERN DUE TO MELTING WILL BE THE BLACK RIVER
NEAR BESSEMER...THE TRAP ROCK RIVER...THE STURGEON RIVER OF
BARAGA/HOUGHTON COUNTIES...THE PESHEKEE RIVER...THE PAINT RIVER NEAR
CRYSTAL FALLS...THE ONTONAGON RIVER AT EWEN...THE CHOCOLAY RIVER
NEAR HARVEY...AND EVENTUALLY THE MICHIGAMME RIVER NEAR REPUBLIC AND
WITCH LAKE. MELTING SCENARIOS STILL LEAD TO SIGNIFICANT UNCERTAINTY WITH
THE RIVER FORECASTS FOR THE PESHEKEE AND MICHIGAMME BASINS WHERE
MOST OF THE MELTING HAS NOT HIT ANY OBSERVED RIVER POINTS. AT
OTHER LOCATIONS...SUFFICIENT RUNOFF FROM MELTING HAS BEEN OBSERVED
TO MORE ACCURATELY ASSESS THE MELT RATES FOR THE RIVER MODELS.

AN NWS SURVEY OF THE PESHEKEE RIVER MONDAY MORNING REVEALED THICK
ICE COVERING MOST OF THE RIVER NEAR AND DOWNSTREAM OF THE CHPM4
RIVER GAUGING LOCATION/AUTOMATED GAUGE DISCONTINUED BUT OBS ARE
BEING TAKEN USING A WIREWEIGHT GAUGE AT THE LOCATION/ AND THICK ICE
COVER ON MOST OF LAKE MICHIGAMME WHICH THE PESHEKEE DRAINS INTO. A
FEW ICE JAMS WERE NOTED MONDAY MORNING WHICH COULD CAUSE SOME
PROBLEMS OVER THE NEXT COUPLE OF DAYS AS THE RIVER RISES.

MAIN STEM RIVERS ARE NOT THE ONLY HAZARD...AS THERE IS ALSO A THREAT
OF AREAL FLOODING WITH SMALLER CREEKS/STREAMS AND STANDING WATER ON
ROADS. AREAL TYPE FLOODING HAS BEEN REPORTED...THE MOST WIDESPREAD
OVER GOGEBIC COUNTY WHERE AN AREAL FLOOD WARNING WAS ISSUED THROUGH
TUESDAY EVENING. FOR COMPLETE DETAILS...SEE THE LATEST RIVER FLOOD
WATCHES...WARNINGS AND ADVISORIES.
&&

.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
  FLASH FLOOD WATCH THROUGH THIS EVENING FOR MIZ009.

LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&

$$

SHORT TERM...JLB
LONG TERM...07
AVIATION...JLB
MARINE...07
HYDROLOGY...JLB







AREA FORECAST DISCUSSION

NWS HASTINGS NE

 706 AM CDT TUE APR 30 2013

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 545 AM CDT TUE APR 30 2013

CLEARLY THE MAIN CONCERN DURING THE NEXT 24 HOURS IS THE RISK FOR
POTENTIALLY SEVERAL STRONG TO SEVERE STORMS MAINLY BETWEEN 7 PM
AND 3 AM TONIGHT...AND MAINLY WITHIN THE SOUTHEAST 1/2 OF THE CWA.
OTHERWISE...TODAY MARKS THE TRANSITION DAY BETWEEN THE 80+ DEGREE
WARMTH OF THE PAST FEW DAYS...AND THE UNWELCOME RETURN TO A WINTRY
FEEL TOMORROW.

09Z OBJECTIVE SURFACE ANALYSIS IS HIGHLIGHTED BY THE MUCH-
ADVERTISED COLD FRONT...THAT PER AUTOMATED OBS AND RADAR IMAGERY
IS ALREADY WELL THROUGH AT LEAST THE NORTHWEST 1/3 OF THE
CWA...AND CONTINUES STEADILY PASSING SOUTHEAST. BEHIND THE FRONT
ARE NORTH-NORTHWEST WINDS WITH SUSTAINED SPEEDS GENERALLY 10-20
MPH WITH HIGHER GUSTS. THIS FRONT IS CONNECTED ACROSS THE REGION
BY TWO PRIMARY SURFACE LOW CENTERS...A 991 MILLIBAR NEAR THE
SD/ND/MN BORDER...AND A 996MB ONE ALONG THE KS/CO BORDER. AHEAD OF
THE FRONT...STEADY SOUTH-SOUTHWEST BREEZES 10-20 MPH HAVE BEEN THE
NORM THROUGH THE NIGHT...PROMOTING VERY MILD READINGS MAINLY IN
THE 60S. ALTHOUGH TEMPS ARE FALLING OFF SOMEWHAT BEHIND THE
BOUNDARY...A GOOD CHUNK OF THE CWA SHOULD MAKE IT THROUGH 8AM
WITHOUT DROPPING BELOW THE 55-60 RANGE. ALOFT...WATER VAPOR
IMAGERY AND SHORT TERM MODEL DATA HIGHLIGHT A LARGE SCALE TROUGH
AND ASSOCIATED UPPER JET STREAK CENTERED OVER THE NORTHERN
PLAINS/ROCKIES...WITH SEVERAL EMBEDDED SHORTWAVE TROUGHS...THE
MOST VIGOROUS OF WHICH IS SWINGING ALONG THE SD/CANADA BORDER.

FOR THE 7AM-7PM DAYTIME PERIOD...THE VAST MAJORITY...IF NOT THE
ENTIRE CWA SHOULD REMAIN THUNDERSTORM/RAIN FREE...AND ONLY HAVE A
SLIGHT CHANCE OF STORMS AFTER 5 PM IN FAR SOUTHEAST ZONES MAINLY
SOUTHEAST OF A HEBRON-PLAINVILLE LINE. ALOFT...BROAD WEST-
SOUTHWEST FLOW WILL PERSIST OVER THE CENTRAL PLAINS...AS THE
VIGOROUS VORT MAX OVER SD SWINGS NORTHEAST INTO CANADA...WHILE
ADDITIONAL PIECES OF ENERGY SLIDE SOUTHEAST OUT OF THE NORTHWEST
CONUS TOWARD THE CENTRAL ROCKIES...HELPING TO SLOWLY DEEPEN THE
DEVELOPING POSITIVELY TILTED LARGE SCALE TROUGH. AT THE
SURFACE...THE COLD FRONT WILL CONTINUE MAKING STEADY PROGRESS
SOUTHWARD ACROSS THE CWA TODAY...ALTHOUGH IT WILL SLOW AND
ESSENTIALLY STALL OUT AS IT REACHES FAR SOUTHEAST COUNTIES...AS IT
IS COUNTER-ACTED BY A STRENGTHENING WARM FRONT/INVERTED TROUGH
AXIS EXTENDING NORTHEAST FROM A DEEPENING SURFACE LOW NEAR THE
CO/OK/KS/TX BORDER AREA. FOR THE MAJORITY OF THE CWA THAT GETS
BEHIND THE COLD FRONT TODAY...BREEZES WILL AVERAGE AT LEAST 15-20
MPH WITH HIGHER GUSTS...AS THE WIND DIRECTION GRADUALLY SHIFTS
FROM NORTHERLY TO NORTHEASTERLY. TEMPERATURE-WISE...DESPITE
PASSING HIGH CLOUDS...ITS NOW LOOKING LIKE THERE WILL BE ENOUGH
SUNSHINE...AND ALSO WEAK ENOUGH COLD AIR ADVECTION TO ALLOW TEMPS
TO CLIMB HIGHER THAN PREVIOUSLY FORECAST...AND BASED ON A BLEND OF
VARIOUS MODELS/GUIDANCE HAVE RAISED HIGHS ROUGHLY 5 DEGREES ALL
AREAS...NOW AIMING FOR MID 60S NORTHWEST...NEAR 70 CENTRAL...AND
LOW 80S FAR SOUTHEAST. IF THE RAP MODEL IS ONTO SOMETHING...IT MAY
BE EVEN WARMER YET...BUT HAVE LARGELY DISCOUNTED IT FOR NOW. AS
FOR PRE-7PM STORM CHANCES...THEY ARE LOOKING FAIRLY SLIM DESPITE
THE LATEST NAM BUILDING 1000+ J/KG OF 0-1MLCAPE IN FAR SOUTHEAST
ZONES LATE THIS AFTERNOON. FORECAST SOUNDINGS SHOW A PRETTY
FORMIDABLE CAP TO SURFACE-BASED CONVECTION OWING TO WARM 700MB
TEMPS IN AN ELEVATED MIXED LAYER. PER REFLECTIVITY FORECAST FROM
THE 00Z 4KM WRF-NMM AND ALSO THE 09Z RAP...THAYER AND MITCHELL
COUNTIES WOULD BEAR THE MOST WATCHING FOR POSSIBLE STORM
DEVELOPMENT...WHICH COULD BECOME SEVERE QUICKLY SHOULD IT FORM.
ALTHOUGH A BRIEF NEAR-SURFACE BASED SUPERCELL CANNOT BE RULED
OUT...IT WOULD LIKELY TAKE ON A SOMEWHAT LINEAR TENDENCY PRETTY
QUICKLY WITH FLOW ALOFT PARALLEL TO THE LOW LEVEL FRONTAL ZONE.

TURNING TO THE 7PM-7AM TONIGHT PERIOD...CONFIDENCE IS CONSIDERABLY
HIGHER IN WIDESPREAD SHOWER/THUNDERSTORM DEVELOPMENT...ESPECIALLY
AFTER SUNSET...AND POPS HAVE BEEN BUMPED UP INTO THE 80-90 PERCENT
RANGE FOR MUCH OF THE NIGHT. ALOFT...SHORTWAVE ENERGY WILL
TRANSLATE INTO THE PLAINS FROM THE WEST AS THE PARENT LONGWAVE
TROUGH SETS UP ALONG AN AXIS FROM ND TO THE CENTRAL ROCKIES BY
SUNRISE WEDNESDAY MORNING. WITHIN THE ENTRANCE REGION OF A DAKOTAS
UPPER JET STREAK...LOW-MID LEVEL SOUTHERLY WINDS SPEEDS/RESULTANT
MOISTURE CONVERGENCE WILL RAMP UP MARKEDLY AROUND/AFTER
SUNSET INTO THE FRONTAL ZONE...WITH MOISTURE TRANSPORT SURGING
INTO THE CWA EVIDENT AT BOTH 850 AND 700MB. VARIOUS MODEL
QPF/REFLECTIVITY PROGS SUCH AS FROM THE NAM AND 4KM WRF-NMM AGREE
ON THE SCENARIO OF A RAPID INCREASE IN THUNDERSTORM DEVELOPMENT
THIS EVENING ACROSS MOST IF NOT ALL OF THE CWA...BUT ESPECIALLY
THE SOUTHEAST 1/2. THIS SHOULD BE A FAIRLY CLASSIC SETUP FOR AT
LEAST MARGINALLY SEVERE HAIL AROUND QUARTER SIZE OR SLIGHTLY
LARGER...WITH A CONSENSUS OF THE LATEST NAM/GFS SUGGESTING AT
LEAST 500-1500 J/KG OF MUCAPE IN THE 850-700MB LAYER THROUGH
06Z...IN THE PRESENCE OF DEEP LAYER 0-6KM SHEAR OF GENERALLY 40-60
KT. THIS COULD YIELD AT LEAST A HANDFUL OF ELEVATED SUPERCELL
STRUCTURES TRAINING WITHIN THE SAME GENERAL CORRIDOR...NOT ALL
THAT UNLIKE THE EVENT IN EARLY APRIL THAT AFFECTED MUCH OF THE NEB
CWA. ALTHOUGH A STRONG STORM IS POSSIBLE ALMOST ANYWHERE...THE
GREATEST THREAT FOR LARGE HAIL AND POSSIBLY SEVERE WIND GUSTS
SHOULD RESIDE GENERALLY SOUTH OF AN ELWOOD-OSCEOLA LINE INCLUDING
KS COUNTIES. GRADUALLY DECREASING INSTABILITY SHOULD RESULT IN A
DECREASING SEVERE THREAT BY AROUND 3 AM OR SO...BUT NOT
NECESSARILY SO. SOME PLACES COULD ALSO PICK UP HEALTHY RAINFALL
AMOUNTS OF 1-2+ INCHES...BUT NOT FORESEEING MUCH OF AN ORGANIZED
FLOODING THREAT GIVEN THE RECENT WARM...DRY STRETCH. ALL OF THIS
WILL BE TAKING PLACE IN THE PRESENCE OF STEADY LOW LEVEL COLD AIR
ADVECTION...MARKED BY NORTH-NORTHEAST WINDS OF AT LEAST 20 MPH AND
POSSIBLY CLOSER TO SUSTAINED 30 MPH AT TIMES EVEN OUTSIDE STORM
ACTIVITY. BY SUNRISE WEDNESDAY MORNING...HAVE LOW TEMPS AIMED FROM
THE MID 30S IN NORTHWEST COUNTIES...TO LOW-MID 40S SOUTHEAST. ITS
NOT COMPLETELY OUT OF THE QUESTION THAT SOME SNOW COULD START
MIXING IN WITH RAIN BETWEEN 09Z-12Z...IN FAR NORTHWEST ZONES...BUT
WOULD EXPECT LITTLE IF ANY ACCUMULATION BEFORE SUNRISE...AND EVEN
THEN ONLY IN THE VALLEY/WESTERN DAWSON COUNTY AREA.

.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 545 AM CDT TUE APR 30 2013

BIGGEST CHALLENGE WILL BE DETERMINING TIMING OF CHANGEOVER TO SNOW
WEDNESDAY AND DETERMINING SNOW AMOUNTS THROUGH WEDNESDAY NIGHT.

WE KICK OFF WEDNESDAY WITH A HIGHLY AMPLIFIED UPPER LEVEL TROUGH
OVER THE INTERMOUNTAIN WEST THAT WILL CONTINUE TO AMPLIFY AND HEAD
TOWARD THE CENTRAL PLAINS. PLENTY OF COLD AIR ADVECTION WILL BE
UNDERWAY...BUT ELEVATED CONVECTION COULD STILL BE OCCURRING DURING
THE EARLY MORNING ON WEDNESDAY IN OUR SOUTHEAST. PROBABLY NOT ENOUGH
INSTABILITY FOR SEVERE WEATHER ANYMORE. ALSO...TEMPERATURES WILL NOT
GO ANYWHERE ON WEDNESDAY WITH THE STRONG COLD AIR ADVECTION...SO
TEMPERATURES WILL BE STEADY OR FALLING DURING THE DAY WITH MIX OF
SNOW/SNOW WORKING IN TO THE SOUTHEAST DURING THE DAY. WIND WILL BE
QUITE PERSISTENT FROM THE NORTH...ESPECIALLY TO THE SOUTH WITH STRONG
HEIGHT RISES. WE COULD BE PUSHING WIND ADVISORY OVER NORTH CENTRAL
KANSAS.

LOOKS A LITTLE TRICKY FOR TIMING OF SWITCHING OVER TO SNOW...AND
TOWARD A MIDDLE OF THE ROAD APPROACH AMONG MODEL
SOLUTIONS...CONSIDERING TIMING AND QPF AMOUNTS. WE COULD PICK UP ONE
TO THREE INCHES...BUT MOST OF THIS WOULD BE ON GRASSY
SURFACES...CONSIDERING THAT THIS WILL BE IN THE MONTH OF MAY.
ALSO...THE NAM INDICATES A POSSIBLE LOSS OF SATURATION IN THE DENDRITIC
GROWTH ZONE LATE AFTERNOON AND EVENING WEDNESDAY...WHICH COULD GIVE
US SOME DRIZZLE/FREEZING DRIZZLE FOR A SHORT PERIOD. ALSO...SLEET
MIGHT NOT BE OUT OF THE QUESTION ACCORDING TO SOME MODEL
SUGGESTIONS...BUT I WILL LEAVE BOTH OUT FOR NOW...AS IT DOES NOT
LOOK THAT LIKELY FOR MUCH SLEET WITH SUCH STRONG COLD AIR ADVECTION
AND THE LACK OF SATURATION IN THE DENDRITIC GROWTH ZONE IS VERY
DICEY.

WE COULD STILL HAVE SOME LEFTOVER SNOW IN THE SOUTH/EAST ON THURSDAY
MORNING AS THE TROUGH AXIS WILL NOT PASS TO THE EAST OF THE CWA
UNTIL AT LEAST AFTERNOON.

MODELS THEN CLOSE OFF A LOW WITHIN THE TROUGH BY THURSDAY NIGHT AND
TO BE HONEST...IT IS A FREE FOR ALL FRIDAY THROUGH THE REST OF THE
LONG TERM FORECAST AS THERE IS ABSOLUTELY NO AGREEMENT AMONG MODELS
OF WHAT HAPPENS WITH THE UPPER LOW. ENSEMBLES ARE OUT OF PHASE AS
WELL. STAYING WITH CONTINUITY HERE...BUT CONFIDENCE IS NOT HIGH WITH
THE LATEST FORECASTS FROM MODELS. WE CAN ONLY HOPE FOR SOME SORT OF
AGREEMENT DEVELOPING IN THE NEAR FUTURE. THERE IS GREAT POTENTIAL
FOR BIG BUSTS FOR TEMPERATURE FORECASTS...ESPECIALLY HIGH
TEMPERATURES...AND WE COULD VERY WELL END UP MUCH COOLER THAN
CURRENTLY ADVERTISED.

&&

.AVIATION...(FOR THE 12Z KGRI TAF THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 700 AM CDT TUE APR 30 2013

VFR CEILING/VISIBILITY ARE CURRENTLY FORECAST THROUGH THE NEXT 24
HOURS...ALTHOUGH THIS IS BY NO MEANS A SURE-THING DURING THE FINAL
6-9 HOURS OF THE PERIOD AS WIDESPREAD THUNDERSTORM ACTIVITY IS
EXPECTED TO DEVELOP ACROSS SOUTHERN NEBRASKA...AND LIKELY AFFECT
KGRI DIRECTLY TO SOME DEGREE. PRIOR TO THUNDERSTORM
DEVELOPMENT...CONFIDENCE IS HIGH IN VFR CONDITIONS...AS THE
DAYTIME AND EARLY EVENING SHOULD ONLY FEATURE PASSING HIGH CLOUDS
GENERALLY AROUND 20K FEET. WITHIN THE PAST HOUR...A FAIRLY SHARP
COLD FRONT HAS PASSED THROUGH KGRI...SWITCHING WINDS TO THE NORTH.
THESE WINDS WILL GRADUALLY TRANSITION TO NORTHEASTERLY DURING THE
DAY...AND FEATURE GUST POTENTIAL TO AROUND 25KT. HAVEN/T GOTTEN
INTO TOO MUCH DETAIL YET WITH THE THUNDERSTORM SITUATION
TONIGHT...BUT HAVE MAINTAINED A VICINITY MENTION STARTING AT
03Z...AND THEN PREVAILING -TSRA FROM 06Z ONWARD. OBVIOUSLY LATER
FORECASTS WILL REFINE TIMING AND ACCOUNT FOR POSSIBLE SUB-VFR
CONDITIONS AS CEILINGS AND VISIBILITY LOWER IN AREAS OF STEADIER
RAIN. A FEW STORMS IN THE AREA TONIGHT COULD ALSO BECOME STRONG
ENOUGH TO PRODUCE HAIL.

&&

.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&

$$

SHORT TERM...PFANNKUCH
LONG TERM...HEINLEIN
AVIATION...PFANNKUCH





AREA FORECAST DISCUSSION

NWS HASTINGS NE

 556 AM CDT TUE APR 30 2013

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 545 AM CDT TUE APR 30 2013

CLEARLY THE MAIN CONCERN DURING THE NEXT 24 HOURS IS THE RISK FOR
POTENTIALLY SEVERAL STRONG TO SEVERE STORMS MAINLY BETWEEN 7 PM
AND 3 AM TONIGHT...AND MAINLY WITHIN THE SOUTHEAST 1/2 OF THE CWA.
OTHERWISE...TODAY MARKS THE TRANSITION DAY BETWEEN THE 80+ DEGREE
WARMTH OF THE PAST FEW DAYS...AND THE UNWELCOME RETURN TO A WINTRY
FEEL TOMORROW.

09Z OBJECTIVE SURFACE ANALYSIS IS HIGHLIGHTED BY THE MUCH-
ADVERTISED COLD FRONT...THAT PER AUTOMATED OBS AND RADAR IMAGERY
IS ALREADY WELL THROUGH AT LEAST THE NORTHWEST 1/3 OF THE
CWA...AND CONTINUES STEADILY PASSING SOUTHEAST. BEHIND THE FRONT
ARE NORTH-NORTHWEST WINDS WITH SUSTAINED SPEEDS GENERALLY 10-20
MPH WITH HIGHER GUSTS. THIS FRONT IS CONNECTED ACROSS THE REGION
BY TWO PRIMARY SURFACE LOW CENTERS...A 991 MILLIBAR NEAR THE
SD/ND/MN BORDER...AND A 996MB ONE ALONG THE KS/CO BORDER. AHEAD OF
THE FRONT...STEADY SOUTH-SOUTHWEST BREEZES 10-20 MPH HAVE BEEN THE
NORM THROUGH THE NIGHT...PROMOTING VERY MILD READINGS MAINLY IN
THE 60S. ALTHOUGH TEMPS ARE FALLING OFF SOMEWHAT BEHIND THE
BOUNDARY...A GOOD CHUNK OF THE CWA SHOULD MAKE IT THROUGH 8AM
WITHOUT DROPPING BELOW THE 55-60 RANGE. ALOFT...WATER VAPOR
IMAGERY AND SHORT TERM MODEL DATA HIGHLIGHT A LARGE SCALE TROUGH
AND ASSOCIATED UPPER JET STREAK CENTERED OVER THE NORTHERN
PLAINS/ROCKIES...WITH SEVERAL EMBEDDED SHORTWAVE TROUGHS...THE
MOST VIGOROUS OF WHICH IS SWINGING ALONG THE SD/CANADA BORDER.

FOR THE 7AM-7PM DAYTIME PERIOD...THE VAST MAJORITY...IF NOT THE
ENTIRE CWA SHOULD REMAIN THUNDERSTORM/RAIN FREE...AND ONLY HAVE A
SLIGHT CHANCE OF STORMS AFTER 5 PM IN FAR SOUTHEAST ZONES MAINLY
SOUTHEAST OF A HEBRON-PLAINVILLE LINE. ALOFT...BROAD WEST-
SOUTHWEST FLOW WILL PERSIST OVER THE CENTRAL PLAINS...AS THE
VIGOROUS VORT MAX OVER SD SWINGS NORTHEAST INTO CANADA...WHILE
ADDITIONAL PIECES OF ENERGY SLIDE SOUTHEAST OUT OF THE NORTHWEST
CONUS TOWARD THE CENTRAL ROCKIES...HELPING TO SLOWLY DEEPEN THE
DEVELOPING POSITIVELY TILTED LARGE SCALE TROUGH. AT THE
SURFACE...THE COLD FRONT WILL CONTINUE MAKING STEADY PROGRESS
SOUTHWARD ACROSS THE CWA TODAY...ALTHOUGH IT WILL SLOW AND
ESSENTIALLY STALL OUT AS IT REACHES FAR SOUTHEAST COUNTIES...AS IT
IS COUNTER-ACTED BY A STRENGTHENING WARM FRONT/INVERTED TROUGH
AXIS EXTENDING NORTHEAST FROM A DEEPENING SURFACE LOW NEAR THE
CO/OK/KS/TX BORDER AREA. FOR THE MAJORITY OF THE CWA THAT GETS
BEHIND THE COLD FRONT TODAY...BREEZES WILL AVERAGE AT LEAST 15-20
MPH WITH HIGHER GUSTS...AS THE WIND DIRECTION GRADUALLY SHIFTS
FROM NORTHERLY TO NORTHEASTERLY. TEMPERATURE-WISE...DESPITE
PASSING HIGH CLOUDS...ITS NOW LOOKING LIKE THERE WILL BE ENOUGH
SUNSHINE...AND ALSO WEAK ENOUGH COLD AIR ADVECTION TO ALLOW TEMPS
TO CLIMB HIGHER THAN PREVIOUSLY FORECAST...AND BASED ON A BLEND OF
VARIOUS MODELS/GUIDANCE HAVE RAISED HIGHS ROUGHLY 5 DEGREES ALL
AREAS...NOW AIMING FOR MID 60S NORTHWEST...NEAR 70 CENTRAL...AND
LOW 80S FAR SOUTHEAST. IF THE RAP MODEL IS ONTO SOMETHING...IT MAY
BE EVEN WARMER YET...BUT HAVE LARGELY DISCOUNTED IT FOR NOW. AS
FOR PRE-7PM STORM CHANCES...THEY ARE LOOKING FAIRLY SLIM DESPITE
THE LATEST NAM BUILDING 1000+ J/KG OF 0-1MLCAPE IN FAR SOUTHEAST
ZONES LATE THIS AFTERNOON. FORECAST SOUNDINGS SHOW A PRETTY
FORMIDABLE CAP TO SURFACE-BASED CONVECTION OWING TO WARM 700MB
TEMPS IN AN ELEVATED MIXED LAYER. PER REFLECTIVITY FORECAST FROM
THE 00Z 4KM WRF-NMM AND ALSO THE 09Z RAP...THAYER AND MITCHELL
COUNTIES WOULD BEAR THE MOST WATCHING FOR POSSIBLE STORM
DEVELOPMENT...WHICH COULD BECOME SEVERE QUICKLY SHOULD IT FORM.
ALTHOUGH A BRIEF NEAR-SURFACE BASED SUPERCELL CANNOT BE RULED
OUT...IT WOULD LIKELY TAKE ON A SOMEWHAT LINEAR TENDENCY PRETTY
QUICKLY WITH FLOW ALOFT PARALLEL TO THE LOW LEVEL FRONTAL ZONE.

TURNING TO THE 7PM-7AM TONIGHT PERIOD...CONFIDENCE IS CONSIDERABLY
HIGHER IN WIDESPREAD SHOWER/THUNDERSTORM DEVELOPMENT...ESPECIALLY
AFTER SUNSET...AND POPS HAVE BEEN BUMPED UP INTO THE 80-90 PERCENT
RANGE FOR MUCH OF THE NIGHT. ALOFT...SHORTWAVE ENERGY WILL
TRANSLATE INTO THE PLAINS FROM THE WEST AS THE PARENT LONGWAVE
TROUGH SETS UP ALONG AN AXIS FROM ND TO THE CENTRAL ROCKIES BY
SUNRISE WEDNESDAY MORNING. WITHIN THE ENTRANCE REGION OF A DAKOTAS
UPPER JET STREAK...LOW-MID LEVEL SOUTHERLY WINDS SPEEDS/RESULTANT
MOISTURE CONVERGENCE WILL RAMP UP MARKEDLY AROUND/AFTER
SUNSET INTO THE FRONTAL ZONE...WITH MOISTURE TRANSPORT SURGING
INTO THE CWA EVIDENT AT BOTH 850 AND 700MB. VARIOUS MODEL
QPF/REFLECTIVITY PROGS SUCH AS FROM THE NAM AND 4KM WRF-NMM AGREE
ON THE SCENARIO OF A RAPID INCREASE IN THUNDERSTORM DEVELOPMENT
THIS EVENING ACROSS MOST IF NOT ALL OF THE CWA...BUT ESPECIALLY
THE SOUTHEAST 1/2. THIS SHOULD BE A FAIRLY CLASSIC SETUP FOR AT
LEAST MARGINALLY SEVERE HAIL AROUND QUARTER SIZE OR SLIGHTLY
LARGER...WITH A CONSENSUS OF THE LATEST NAM/GFS SUGGESTING AT
LEAST 500-1500 J/KG OF MUCAPE IN THE 850-700MB LAYER THROUGH
06Z...IN THE PRESENCE OF DEEP LAYER 0-6KM SHEAR OF GENERALLY 40-60
KT. THIS COULD YIELD AT LEAST A HANDFUL OF ELEVATED SUPERCELL
STRUCTURES TRAINING WITHIN THE SAME GENERAL CORRIDOR...NOT ALL
THAT UNLIKE THE EVENT IN EARLY APRIL THAT AFFECTED MUCH OF THE NEB
CWA. ALTHOUGH A STRONG STORM IS POSSIBLE ALMOST ANYWHERE...THE
GREATEST THREAT FOR LARGE HAIL AND POSSIBLY SEVERE WIND GUSTS
SHOULD RESIDE GENERALLY SOUTH OF AN ELWOOD-OSCEOLA LINE INCLUDING
KS COUNTIES. GRADUALLY DECREASING INSTABILITY SHOULD RESULT IN A
DECREASING SEVERE THREAT BY AROUND 3 AM OR SO...BUT NOT
NECESSARILY SO. SOME PLACES COULD ALSO PICK UP HEALTHY RAINFALL
AMOUNTS OF 1-2+ INCHES...BUT NOT FORESEEING MUCH OF AN ORGANIZED
FLOODING THREAT GIVEN THE RECENT WARM...DRY STRETCH. ALL OF THIS
WILL BE TAKING PLACE IN THE PRESENCE OF STEADY LOW LEVEL COLD AIR
ADVECTION...MARKED BY NORTH-NORTHEAST WINDS OF AT LEAST 20 MPH AND
POSSIBLY CLOSER TO SUSTAINED 30 MPH AT TIMES EVEN OUTSIDE STORM
ACTIVITY. BY SUNRISE WEDNESDAY MORNING...HAVE LOW TEMPS AIMED FROM
THE MID 30S IN NORTHWEST COUNTIES...TO LOW-MID 40S SOUTHEAST. ITS
NOT COMPLETELY OUT OF THE QUESTION THAT SOME SNOW COULD START
MIXING IN WITH RAIN BETWEEN 09Z-12Z...IN FAR NORTHWEST ZONES...BUT
WOULD EXPECT LITTLE IF ANY ACCUMULATION BEFORE SUNRISE...AND EVEN
THEN ONLY IN THE VALLEY/WESTERN DAWSON COUNTY AREA.

.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 545 AM CDT TUE APR 30 2013

BIGGEST CHALLENGE WILL BE DETERMINING TIMING OF CHANGEOVER TO SNOW
WEDNESDAY AND DETERMINING SNOW AMOUNTS THROUGH WEDNESDAY NIGHT.

WE KICK OFF WEDNESDAY WITH A HIGHLY AMPLIFIED UPPER LEVEL TROUGH
OVER THE INTERMOUNTAIN WEST THAT WILL CONTINUE TO AMPLIFY AND HEAD
TOWARD THE CENTRAL PLAINS. PLENTY OF COLD AIR ADVECTION WILL BE
UNDERWAY...BUT ELEVATED CONVECTION COULD STILL BE OCCURRING DURING
THE EARLY MORNING ON WEDNESDAY IN OUR SOUTHEAST. PROBABLY NOT ENOUGH
INSTABILITY FOR SEVERE WEATHER ANYMORE. ALSO...TEMPERATURES WILL NOT
GO ANYWHERE ON WEDNESDAY WITH THE STRONG COLD AIR ADVECTION...SO
TEMPERATURES WILL BE STEADY OR FALLING DURING THE DAY WITH MIX OF
SNOW/SNOW WORKING IN TO THE SOUTHEAST DURING THE DAY. WIND WILL BE
QUITE PERSISTENT FROM THE NORTH...ESPECIALLY TO THE SOUTH WITH STRONG
HEIGHT RISES. WE COULD BE PUSHING WIND ADVISORY OVER NORTH CENTRAL
KANSAS.

LOOKS A LITTLE TRICKY FOR TIMING OF SWITCHING OVER TO SNOW...AND
TOWARD A MIDDLE OF THE ROAD APPROACH AMONG MODEL
SOLUTIONS...CONSIDERING TIMING AND QPF AMOUNTS. WE COULD PICK UP ONE
TO THREE INCHES...BUT MOST OF THIS WOULD BE ON GRASSY
SURFACES...CONSIDERING THAT THIS WILL BE IN THE MONTH OF MAY.
ALSO...THE NAM INDICATES A POSSIBLE LOSS OF SATURATION IN THE DENDRITIC
GROWTH ZONE LATE AFTERNOON AND EVENING WEDNESDAY...WHICH COULD GIVE
US SOME DRIZZLE/FREEZING DRIZZLE FOR A SHORT PERIOD. ALSO...SLEET
MIGHT NOT BE OUT OF THE QUESTION ACCORDING TO SOME MODEL
SUGGESTIONS...BUT I WILL LEAVE BOTH OUT FOR NOW...AS IT DOES NOT
LOOK THAT LIKELY FOR MUCH SLEET WITH SUCH STRONG COLD AIR ADVECTION
AND THE LACK OF SATURATION IN THE DENDRITIC GROWTH ZONE IS VERY
DICEY.

WE COULD STILL HAVE SOME LEFTOVER SNOW IN THE SOUTH/EAST ON THURSDAY
MORNING AS THE TROUGH AXIS WILL NOT PASS TO THE EAST OF THE CWA
UNTIL AT LEAST AFTERNOON.

MODELS THEN CLOSE OFF A LOW WITHIN THE TROUGH BY THURSDAY NIGHT AND
TO BE HONEST...IT IS A FREE FOR ALL FRIDAY THROUGH THE REST OF THE
LONG TERM FORECAST AS THERE IS ABSOLUTELY NO AGREEMENT AMONG MODELS
OF WHAT HAPPENS WITH THE UPPER LOW. ENSEMBLES ARE OUT OF PHASE AS
WELL. STAYING WITH CONTINUITY HERE...BUT CONFIDENCE IS NOT HIGH WITH
THE LATEST FORECASTS FROM MODELS. WE CAN ONLY HOPE FOR SOME SORT OF
AGREEMENT DEVELOPING IN THE NEAR FUTURE. THERE IS GREAT POTENTIAL
FOR BIG BUSTS FOR TEMPERATURE FORECASTS...ESPECIALLY HIGH
TEMPERATURES...AND WE COULD VERY WELL END UP MUCH COOLER THAN
CURRENTLY ADVERTISED.

&&

.AVIATION...(FOR THE 06Z KGRI TAF THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 100 AM CDT TUE APR 30 2013

VFR CEILING/VISIBILITY ARE CURRENTLY FORECAST THROUGH THE NEXT 24
HOURS...WITH MAINLY JUST PASSING HIGH LEVEL CLOUDS UP AROUND 20K
FEET. HOWEVER...THERE WILL BE INCREASINGLY ACTIVE WEATHER...MAINLY IN
THE FORM OF A SHARP COLD FRONTAL PASSAGE...AND ALSO INCREASING
CHANCES FOR THUNDERSTORMS MAINLY DURING THE FINAL 3 HOURS OF THE
PERIOD TUESDAY NIGHT. STARTING OFF WITH THE VERY SHORT
TERM...SOUTHERLY BREEZES WILL TRANSITION TO WESTERLY THROUGH THE
REST OF THE NIGHT...BEFORE AN ABRUPT SWITCH TO NORTH-NORTHWEST
WINDS ARRIVES AROUND 12Z...WITH GUST POTENTIAL TO AT LEAST 25KT.
PRIOR TO COLD FRONTAL PASSAGE...HAVE INCLUDED A 3-HOUR MENTION OF
LOW LEVEL WIND SHEAR FROM 09Z-12Z AS WINDS ACCELERATE TO AROUND
50KT OUT OF THE SOUTH-SOUTHWEST UP TO AROUND 1500 FT AGL.
NORTHERLY BREEZES WILL REMAIN STEADY THROUGH THE DAY AND INTO THE
EVENING...AND BECOME MORE NORTHEASTERLY WITH TIME. SOMETIME AFTER
SUNSET...A FAIRLY WIDESPREAD AREA OF THUNDERSTORMS IS EXPECTED TO
BLOSSOM ACROSS SOUTHERN NEBRASKA...SOME OF WHICH COULD POTENTIALLY
BECOME STRONG WITH HAIL POTENTIAL. FOR NOW...WILL INTRODUCE A
VICINITY THUNDERSTORM MENTION THROUGH THE FINAL 3 HOURS...WITH
CEILINGS LOWERING TOWARD LOWER-END VFR LEVELS...ALTHOUGH OBVIOUSLY
ANY STORMS DIRECTLY IMPACTING KGRI COULD RESULT IN QUICKLY
DETERIORATING CONDITIONS.

&&

.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&

$$

SHORT TERM...PFANNKUCH
LONG TERM...HEINLEIN
AVIATION...PFANNKUCH





AREA FORECAST DISCUSSION

NWS BUFFALO NY

 1016 AM EDT TUE APR 30 2013

.SYNOPSIS...
A WEAK UPPER LEVEL DISTURBANCE WILL GENERATE A FEW SHOWERS THIS
MORNING...BEFORE SOME SUNSHINE RETURNS DURING THE AFTERNOON.
OTHERWISE...HIGH PRESSURE ANCHORED OFF THE NEW ENGLAND COAST WILL
REMAIN IN PLACE FOR THE REST OF THE WEEK AND PROVIDE US WITH MORE
SUNSHINE AND WELL ABOVE AVERAGE TEMPERATURES.

&&

.NEAR TERM /THROUGH TONIGHT/...
HIGH PRESSURE REMAINS ANCHORED JUST OFF THE NEW ENGLAND COAST WITH
SURFACE RIDGING EXTENDED WEST ACROSS NEW YORK STATE THIS MORNING.
WELL TO THE WEST LOW PRESSURE IS CENTERED OVER MINNESOTA WITH A COLD
FRONT EXTENDED SOUTH INTO THE CENTRAL PLAINS. A THUNDERSTORM COMPLEX
IS ALSO FOUND ACROSS MICHIGAN FUELED BY DEEP MOISTURE AND FORCED BY
A 50 KNOT LOW LEVEL JET OUT AHEAD OF THE  MINNESOTA LOW. FOR OUR
WEATHER TODAY WE HAVE A MOIST SOUTHERLY FLOW WHICH IS GENERATING
WIDESPREAD CLOUDINESS WITH KBUF/KTYX RADARS SHOWING WEAKENING TREND
TO SCATTERED RAIN SHOWERS FOCUSED MAINLY ACROSS THE FINGER LAKES
LATE THIS MORNING.

THESE SHOWERS FORMED AHEAD OF A WELL DEFINED MID LEVEL SHORT
WAVE TROUGH THAT IS SHIFTING ACROSS WESTERN NEW YORK. THE MODELS
GENERALLY AGREE THAT THIS IMPULSE WILL CROSS OUR CWA THROUGH THE
EARLY AFTERNOON...THEN DROP INTO SOUTHEAST NY AND EASTERN PA BY
EARLY EVENING. WILL MAINTAIN CHANCE OF SHOWERS THIS MORNING FOLLOWED
BY A DECREASING TREND FROM WEST TO EAST DURING THE AFTERNOON.

AS FAR AS THE THUNDERSTORM COMPLEX OVER MICHIGAN...SHORT TERM MODEL
GUIDANCE INCLUDING THE 12Z HRRR AND 03Z SREF SHOW THIS COMPLEX
LIFTING TO THE NORTHEAST WITHING THE SOUTHWESTERLY FLOW ALOFT AND
FALLING APART ALONG ITS SOUTHERN EDGE THROUGH THE AFTERNOON AS IT MOVES
TOWARD A BUILDING UPPER LEVEL RIDGE AND ASSOCIATED DOWNWARD MOTION
OVER THE EASTERN STATES. BASED ON THIS WE ARE NOT EXPECTING ANY
IMPACT FROM THIS SYSTEM TO OUR FORECAST AREA TODAY. THROUGH THE AFTERNOON
EXPECT A GRADUAL WEST TO EAST DECREASE IN CLOUDS ACROSS OUR AREA.
THE ANTICIPATED INCREASE IN SUNSHINE WILL HELP TO BOOST INTO THE
LOWER 70S ALONG THE LAKE PLAINS. OTHERWISE...EXPECT TEMPERATURES TO
RANGE THROUGH THE 60S.

TONIGHT...THE SURFACE RIDGE WILL REMAIN IN PLACE WHILE THE MINNESOTA
LOW LIFTS NORTH TO JAMES BAY. THE UPPER LEVEL RIDGE MUCH OF THE EAST
COAST IS FORECAST TO BUILD FURTHER WEST ACROSS THE OHIO VALLEY AND
LOWER GREAT LAKES. INCREASING LARGE SCALE SUBSIDENCE ASSOCIATED WITH
THE EXPANDING RIDGE WILL HELP THE CLOUDS TO THIN OUT EVEN
MORE...ALTHOUGH THE MODELS ARE HINTING THAT SOME MID AND HIGH LEVELS
CLOUDS FROM UPSTREAM THUNDERSTORM COMPLEX MAY SPILL ACROSS OUR AREA
DURING THE NIGHT. BEST CHANCE FOR THIS WOULD BE ACROSS LAKE ONTARIO
AND THE EASTERN LAKE ONTARIO REGION. WILL MONITOR THIS SYSTEM
THROUGH THE DAY. MAY HAVE TO INCLUDE A SMALL CHANCE FOR A SHOWER OR
THUNDERSTORM ACROSS LAKE ONTARIO AND TO THE EAST IF SYSTEM HOLDS
TOGETHER A LITTLE BETTER THAN MODELS SHOW. THE MILD SOUTHERLY FLOW
WILL ALSO KEEP AREA TEMPERATURES ABOVE SEASONAL AVERAGES.

&&

.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
THE PATTERN ACROSS NORTH AMERICA WILL CONTINUE TO AMPLIFY ON
WEDNESDAY AS A TROUGH DIGS THROUGH THE ROCKIES AND NORTHERN HIGH
PLAINS...FORCING STRONG DOWNSTREAM HEIGHT RISES ACROSS THE EASTERN
HALF OF THE NATION. INCREASING SUBSIDENCE AND DRYING BENEATH A
BUILDING UPPER LEVEL RIDGE WILL CONTINUE TO ERODE THE LOW/MID LEVEL
MOISTURE THAT WAS LEFT BEHIND BY THE WEAK TROUGH OF THE PAST FEW
DAYS. THIS WILL BRING INCREASING AMOUNTS OF SUNSHINE FOR WEDNESDAY.

850MB TEMPS RISE TO +9C TO +10C BY AFTERNOON...WHICH WILL SUPPORT
HIGHS IN THE MID TO UPPER 70S AT LOWER ELEVATIONS. THE SOUTH TO
SOUTHEAST SYNOPTIC SCALE WIND SHOULD BE STRONG ENOUGH TO PRECLUDE
LAKE BREEZE FORMATION IN MOST AREAS...WITH A FEW POSSIBLE EXCEPTIONS
NOTED IN MESOSCALE MODEL GUIDANCE. IT APPEARS A LOCAL LAKE BREEZE
MAY DEVELOP ALONG THE SOUTH SHORE OF LAKE ONTARIO MAINLY ACROSS THE
NIAGARA AND ORLEANS COUNTY SHORE WITH COOLER TEMPS THERE. GRADIENT
ONSHORE FLOW WILL ALSO KEEP AREAS FROM STONY POINT TO CAPE VINCENT
IN JEFFERSON COUNTY COOLER.

WEDNESDAY NIGHT HIGH PRESSURE REMAINS PARKED ALONG THE NEW ENGLAND
COAST WITH LIGHT SOUTHERLY RETURN FLOW ACROSS THE LOWER LAKES. THIS
WILL KEEP TEMPS UP INTO THE LOWER 50S ON THE LAKE PLAINS OF WESTERN
NY WITH 40S ELSEWHERE.

ON THURSDAY THE MID/UPPER LEVEL RIDGE REMAINS PARKED DIRECTLY
OVERHEAD PROVIDING ANOTHER DRY DAY WITH A GOOD AMOUNT OF SUNSHINE.
850MB TEMPS AROUND +10C WILL AGAIN SUPPORT MID TO UPPER 70S IN MANY
AREAS. SURFACE HIGH PRESSURE WILL BUILD MORE DIRECTLY OVERHEAD ON
THURSDAY...WHICH MEANS SYNOPTIC SCALE FLOW WILL LIKELY BE TOO LIGHT
TO PREVENT LAKE BREEZE FORMATION. THUS...EXPECT ALL THE LAKESHORES
OF BOTH LAKES TO BE COOLER ON THURSDAY.

HIGH PRESSURE SURFACE AND ALOFT REMAINS IN PLACE THURSDAY NIGHT. A
WEAK BAND OF MID LEVEL MOISTURE PEELING OFF A CUTOFF LOW OFF THE NEW
ENGLAND COAST MAY BRING A LITTLE MORE CLOUD COVER TO CENTRAL NY
OVERNIGHT.

&&

.LONG TERM /FRIDAY THROUGH MONDAY/...
AN EXCEPTIONAL PERIOD OF DRY AND WARM WEATHER WILL CONTINUE THROUGH
NEXT WEEKEND AS A PAIR OF CUTOFF LOWS DEVELOP OVER THE CENTRAL CONUS
AND WESTERN ATLANTIC...ALLOWING A NEARLY STATIONARY OMEGA BLOCK TO
DEVELOP OVER THE OHIO VALLEY AND EASTERN GREAT LAKES. THIS WILL
CONTINUE TO PROVIDE DRY WEATHER THROUGH THE WEEKEND WITH NOTHING
MORE THAN A FEW PERIODS OF HIGH CLOUD AS WEAK DISTURBANCES CROSS THE
TOP OF THE RIDGE. 850MB TEMPS WILL RUN IN THE +8C TO +10C RANGE
DAILY WHICH WILL SUPPORT HIGHS WELL INTO THE 70S. MOS GUIDANCE
CONTINUES TO LOOK TOO LOW FOR THIS PERIOD...AS IS TYPICALLY THE CASE
HERE DURING PRE-FOLIAGE WARM SPELLS. WITH HIGH PRESSURE NEARLY
OVERHEAD...SYNOPTIC SCALE WINDS WILL BE LIGHT ENOUGH TO ALLOW LOCAL
LAKE BREEZES TO DEVELOP ON MOST DAYS WITH COOLER TEMPS ALONG THE
LAKESHORES.

BY MONDAY THE CLOSED LOW OVER THE MIDWEST WILL BEGIN TO MAKE A
LITTLE PROGRESS EAST...BUT THE CONSENSUS FROM THE NEW 00Z GFS AND
ECMWF RUNS IS TO KEEP IT FAR ENOUGH WEST FOR ANOTHER DRY DAY ON
MONDAY WITH CONTINUED WARMTH.

&&

.AVIATION /14Z TUESDAY THROUGH SATURDAY/...
VFR CIGS WITH SCATTERED SHOWERS WILL CONTINUE TO DRIFT EAST ACROSS
THE REGION THIS MORNING AS A MID LEVEL SHORT WAVE WORKS ACROSS
WESTERN NEW YORK. THUNDERSTORM COMPLEX TO OUR WEST OVER MICHIGAN
WILL LIFT NORTH AND FALL APART ON ITS SOUTHERN EDGE BEFORE REACHING
WESTERN NEW YORK WITH NO IMPACT EXPECTED AT THE TAF SITES TODAY. ACROSS
THE SOUTHERN TIER KJHW WILL IMPROVE FROM MVFR CIGS TO VFR BY THE
AFTERNOON.

HIGH PRESSURE ANCHORED OFF THE EAST COAST WILL RESULT IN MAINLY VFR
CONDITIONS ACROSS THE REGION TONIGHT. THERE IS A SMALL CHANCE THAT
SOME LINGERING SHOWER/THUNDERSHOWER ACTIVITY FROM THE COMPLEX TO OUR
WEST MAY HOLD TOGETHER ACROSS LAKE ONTARIO AND MAY APPROACH KART
THIS EVENING.

OUTLOOK...
WEDNESDAY THROUGH SATURDAY...VFR.

&&

.MARINE...
A THUNDERSTORM COMPLEX TO OUR WEST OVER MICHIGAN WILL LIFT NORTH
WITH ITS SOUTHERN PORTION FALLING APART BEFORE REACHING EASTERN LAKE
ERIE LATER TODAY. SOME LINGERING SHOWERS/THUNDERSHOWERS CLOSER TO
THE CENTER OF THIS SYSTEM MAY BRUSH THE NORTHERN HALF OF LAKE
ONTARIO LATER THIS EVENING. OTHERWISE...HIGH PRESSURE ANCHORED OFF
THE NEW ENGLAND COAST WILL REMAIN NEARLY STATIONARY THROUGH THE
WEEK. THIS WILL KEEP THE LOWER LAKES IN A A PERSISTENT LIGHT TO
MODEST SOUTHEASTERLY FLOW THAT WILL RESULT IN MINIMAL WAVES ALONG
THE NEARSHORES OF BOTH LAKES.

&&

.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...NONE.

&&

$$

SYNOPSIS...TJP
NEAR TERM...SMITH
SHORT TERM...HITCHCOCK
LONG TERM...HITCHCOCK
AVIATION...SMITH
MARINE...SMITH








AREA FORECAST DISCUSSION

NWS BISMARCK ND

 656 AM CDT TUE APR 30 2013

.UPDATE...
ISSUED AT 654 AM CDT TUE APR 30 2013

THE ONLY SIGNIFICANT CHANGE WITH THIS FORECAST UPDATE TO WAS TO
ADJUST FOR THE STRATUS DECK THAT HAS ENTERED WESTERN NORTH DAKOTA
AND WILL CONTINUE TO PUSH EAST THROUGH THE MORNING...MIXING OUT
THROUGH THE AFTERNOON. THE 10 UTC RAP CAPTURES THIS DECK WELL AND
FOLLOWED IT FOR SKY GRIDS THROUGH THE REMAINDER OF THE DAY.
OTHERWISE...NO CHANGES NEEDED OTHER THAN TO BLEND TO TRENDS
THROUGH 11 UTC.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 413 AM CDT TUE APR 30 2013

CURRENTLY...A BAND OF SHOWERS ARE MOVING NORTH AND EAST OVER THE
JAMES RIVER VALLEY...NORTHEAST THROUGH THE RED RIVER VALLEY.
WITH IN THIS BAND OF SHOWERS...THERE IS AN AREA OF MODERATE TO
HEAVY RAINFALL...PRODUCING A RADAR ESTIMATED HALF TO AN INCH PER
HOUR. THIS AREA OF MODERATE TO HEAVY PRECIP WILL CONTINUE TO MOVE
NORTHEAST AND OVER THE JAMES RIVER VALLEY THIS MORNING AND
AGGRAVATING EXISTING OVERLAND FLOODING ISSUES. SHORT TERM GUIDANCE
CONTINUES TO PUSH THIS BAND OF SHOWER ACTIVITY NORTHEAST...ENDING
ANY CHANCES FOR PRECIPITATION FOR THE JAMES RIVER VALLEY AROUND
12Z THIS MORNING.

THE MAIN FORECAST HIGHLIGHTS FOR THE SHORT TERM PERIOD INCLUDE
FIRE WEATHER (EXPLAINED BELOW) AND WIND HEADLINES.

AS LOW PRESSURE EXITS TO THE NORTHEAST AND HIGH PRESSURE STARTS TO
BUILD SOUTHEAST FROM SOUTHERN CANADA TODAY...STRONG GUSTY WEST TO
NORTHWEST WINDS WILL DEVELOP ACROSS WESTERN AND CENTRAL NORTH
DAKOTA TODAY. THE 00Z NAM/GFS BUFR SOUNDINGS SHOW THE POTENTIAL
FOR MIXING TO BETWEEN 800 AND 750 MB THIS MORNING THROUGH THIS EVENING.
THIS WOULD RESULT IN WINDS AT THIS LEVEL OF 35 TO 50 KTS TO MIX TO
THE SURFACE. THIS WILL ALSO COINCIDE WITH 6-HOUR PRESSURE RISE
MAXIMA OF 9 TO 11 MB THAT IS FORECAST BY THE 00Z GFS TO MOVE OVER
WESTERN AND CENTRAL NORTH DAKOTA BETWEEN 12 AND 00Z. THIS WILL
RESULT IN WINDS THAT WILL BE SUSTAINED OVER 30 MPH...WITH GUSTS TO
NEAR 45 MPH...MEETING ADVISORY CRITERIA. THUS HAVE DECIDED TO
ISSUE A WIND ADVISORY FOR ALL BUT THE NORTHERN TIER OF COUNTIES
THROUGH 00Z. AFTER 00Z...WINDS SHOULD SUBSIDE AS BUFR SOUNDINGS
FORECAST THE DEMISE OF THE MIXED LAYER...DECOUPLING THE SURFACE
AND 800-750MB WINDS.

MEANWHILE...THERE WILL BE A BRIEF PERIOD OF LIGHT MIXED
PRECIPITATION AND SNOW SHOWERS ACROSS THE NORTH THROUGH THIS
EVENING. SNOWFALL ACCUMULATIONS ARE EXPECTED TO BE LIGHT AND LESS
THAN AN INCH.

.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 413 AM  CDT TUE APR 30 2013

THE HIGHLIGHTS OF THE EXTENDED FORECAST ARE BELOW NORMAL
TEMPERATURES WEDNESDAY THROUGH LATE THIS WEEK...WITH SIGNIFICANT
UNCERTAINTY INTO THE WEEKEND AND EARLY NEXT WEEK.

THE 00 UTC DETERMINISTIC AND ENSEMBLE SUITE IS IN GOOD AGREEMENT
TO BEGIN THE EXTENDED...WITH A CENTRAL CONUS LONGWAVE TROUGH
SUPPORTING WIDESPREAD BELOW NORMAL TEMPERATURES IN THE 40S AND 50S
WEDNESDAY AND THURSDAY. THEREAFTER...THE SPREAD OF SOLUTIONS
QUICKLY WIDENS FRIDAY THROUGH THE REMAINDER OF THE EXTENDED IN
REGARDS TO CUTTING OFF OF THE SOUTHERN STREAM ENERGY AND THE
EVENTUAL PROPAGATION OF THE CLOSED LOW THROUGH THE WEEKEND. THE
POSITIONING OF THIS UPPER LEVEL LOW RANGES FROM NORTHERN MINNESOTA
ON SUNDAY ON THE 00 UTC ECMWF...TO MISSOURI ON THE 00 UTC GFS AND
GEFS MEAN...WITH A RANGE IN BETWEEN. CONFIDENCE IN ANY SOLUTION IS
LOW...WITH SIGNIFICANT IMPACTS TO FORECAST TEMPERATURES AND
PRECIPITATION CHANCES. WITH SUCH LITTLE CONFIDENCE AND WIDELY
RANGING SENSIBLE WEATHER...WILL GO WITH A BLEND FOR NOW AND ALLOW
ADDITIONAL MODEL CYCLES TO RESOLVE A GREATER CONSENSUS.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY)
ISSUED AT 654 AM AM CDT TUE APR 30 2013

MVFR STRATUS HAS ENTERED WESTERN NORTH DAKOTA AND WILL CONTINUE TO
PUSH EAST THROUGH THE MORNING...BEFORE SLOWLY LIFTING AND
SCATTERING OUT THROUGH THE AFTERNOON. STRONG WEST-NORTHWEST WIND
GUSTS OF 35-40 KTS ARE EXPECTED AT KDIK...KBIS AND KJMS TODAY...WITH
SLIGHTLY WEAKER WINDS FOR THE KISN AND KMOT TERMINALS. SCATTERED
RAIN AND SNOW SHOWERS ARE FORECAST FOR NORTHERN NORTH DAKOTA.
HOWEVER...DUE TO UNCERTAINTY IN IMPACTS TO TERMINALS...WILL ONLY
CODE AS VCSH IN THE KISN AND KMOT TAF.


&&

.FIRE WEATHER...
ISSUED AT 413 AM  CDT TUE APR 30 2013

FIRE WEATHER CONCERNS WILL CONTINUE TODAY...ESPECIALLY ACROSS
THE FAR SOUTHWEST AND SOUTH CENTRAL COUNTIES. THE FIRE DANGER
INDEX IN THESE AREAS WILL BE IN THE VERY HIGH CATEGORY. THIS IS
MAINLY DUE TO STRONG WEST TO NORTHWEST WINDS GUSTING UP TO NEAR 40
TO 45 MPH. FACTORS AGAINST FIRE WEATHER HEADLINES ARE MIN RH
VALUES IN THE 30S...COOLER TEMPERATURES IN THE 50S AND LINGERING
MOISTURE FROM OVERNIGHT RAIN. HOWEVER...IF THE STRONG WEST TO
NORTHWEST WINDS  DRY OUT THE FUELS FASTER THAN EXPECTED...THEN
HEADLINES MAY BE NEEDED FOR TUESDAY AFTERNOON. WILL MONITOR THIS
SITUATION FOR ANY DEVELOPMENTS.

&&

.HYDROLOGY...
ISSUED AT 413 AM  CDT TUE APR 30 2013

ISSUED A FLOOD ADVISORY FOR STUTSMAN COUNTY THROUGH 330 AM CDT
WEDNESDAY...AS OVERNIGHT RAINFALL COMBINED WITH SNOW MELT FROM THE
WEEKEND MAY LEAD TO FLOODING OF COUNTY AND TOWNSHIP ROADS AND
ADDITIONAL RISES ON FASTER RESPONDING CREEKS AND STREAMS.
OTHERWISE...ACROSS THE SOURIS BASIN...THE DES LACS RIVER AT
FOXHOLM WAS CONTINUING TO FALL...AND IS EXPECTED TO GO BELOW FLOOD
STAGE THIS MORNING. IN GENERAL...ON THE SOURIS RIVER FROM THE
CONFLUENCE WITH THE DES LACS...THROUGH MINOT AND LOGAN...STAGES
ARE STEADY OR FALLING AS THE PEAK OF THE DES LACS FLOWS HAS
PASSED. FROM SAWYER THROUGH WESTHOPE...STAGES ARE EXPECTED TO
CONTINUE TO INCREASE...WITH ADDITIONAL RISES ON THE WINTERING
RIVER AND WILLOW CREEK. THE SOURIS RIVER ABOVE LAKE DARLING WILL
CONTINUE TO RISE THROUGH THIS WEEK FROM RUNOFF BELOW THE CANADIAN
DAMS AND EVENTUAL RESERVOIR RELEASES. FOR THE JAMES BASIN...THE
JAMES RIVER AND PIPESTEM CREEK ABOVE THE RESERVOIRS CONTINUE TO
DEPICT ELEVATED FLOWS...WITH MODERATE FLOODING EXPECTED ON THE
PIPESTEM CREEK NEAR PINGREE.

&&

.BIS WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY UNTIL 7 PM CDT /6 PM MDT/ THIS EVENING FOR
NDZ017>020-031>034-040>045.

WIND ADVISORY FROM 10 AM THIS MORNING TO 7 PM CDT THIS EVENING
FOR NDZ010>013-021>023-025-035>037-046>048-050-051.

&&

$$

UPDATE...AYD
SHORT TERM...LTH
LONG TERM...AYD
AVIATION...LTH
FIRE WEATHER...LTH
HYDROLOGY...AYD







AREA FORECAST DISCUSSION

NWS BLACKSBURG VA

 1012 AM EDT TUE APR 30 2013

.SYNOPSIS...
HIGH PRESSURE ALONG THE MID ATLANTIC COAST WILL PERSIST THROUGH
THE WEEK TO BRING COOL AND CLOUDY CONDITIONS. AN AREA OF LOW
PRESSURE WILL DEVELOP AND LINGER OVER THE GREAT PLAINS...WHICH
COULD AFFECT THE EASTERN UNITED STATES LATE IN THE WEEKEND.

&&

.NEAR TERM /THROUGH TONIGHT/...
AS OF 1010 AM EDT TUESDAY...

THE LATEST 12Z RNK SOUNDING SHOWS BOUNDARY LAYER MOISTURE STILL
IN PLACE...BUT IT HAS BECOME SHALLOWER DURING THE PAST 24 HOURS.
THICK CLOUD COVER STILL HOLDS OVER THE PIEDMONT...BUT A FEW BREAKS
ARE SHOWING IN FAR SOUTHWEST VIRGINIA AND SOUTHEAST WEST VIRGINIA.
SOME INSOLATION SHOULD ALLOW HIGH TEMPERATURES TO AT LEAST REACH
THE VALUES REALIZED YESTERDAY. TEMPERATURES WERE STILL HELD ON THE
COOLER SIDE OF GUIDANCE BUT NOT QUITE AS MUCH IN THIS UPDATE.
ALSO...SLIGHT CHANCE POPS WERE EXPANDED A LITTLE MORE ON THE
WESTERN PERIPHERY OF THE WEDGE GIVEN THE LATEST RAP MODEL
SOLUTION. HOWEVER...THERE IS NO INSTABILITY THAT WOULD SUPPORT
MENTION OF THUNDER BASED ON THE MODEL SOUNDINGS...SO JUST LIGHT
RAIN SHOWERS WERE INCLUDED.

BY TONIGHT...THE POTENTIAL FOR LOW CLOUDS AND FOG SHOULD EMERGE
AGAIN OVER THE CWA. WITH AN AREA OF LOW PRESSURE DEVELOPING
ALONG THE SOUTHEAST COAST...AND HIGH PRESSURE REMAINING FIRM OVER
THE NORTHEAST...THE EASTERLY FLOW COULD BE ENHANCED AND FURTHER
STRENGTHEN THE COOL WEDGE. ALTHOUGH POPS WERE KEPT LOW DURING THIS
PERIOD...SOME DRIZZLE IS CERTAINLY POSSIBLE...ESPECIALLY ALONG THE
EASTERN SIDE OF THE BLUE RIDGE.

&&

.SHORT TERM /WEDNESDAY THROUGH FRIDAY NIGHT/...
AS OF 400 AM EDT TUESDAY...

RIDGING...SITUATED ROUGHLY ALONG THE APPALACHIAN CHAIN...WILL BE THE
DOMINANT FEATURE IN THE UPPER LEVELS FOR THE REMAINDER OF THE
WORKWEEK AS A DEEP UPPER LEVEL TROUGH SINKS SOUTHWARD ACROSS THE
ROCKIES...AND EVENTUALLY PINCHES OFF INTO A CLOSED LOW OVER THE
CENTRAL PLAINS ON FRIDAY. MEANWHILE...HIGH PRESSURE WILL REMAIN
WEDGED AGAINST THE EASTERN FACE OF THE APPALACHIANS INTO THE
WEEKEND...RESULTING IN A PERSISTENT NORTHEASTERLY TO EASTERLY WIND
FLOW ACROSS THE AREA THAT WILL CONTINUE TO DRAW COOL MOIST AIR FROM
THE ATLANTIC.

AS SUCH...WE CAN EXPECT SIMILAR WEATHER CONDITIONS EACH DAY THROUGH
THE PERIOD...WITH PATCHY DENSE FOG AND AREAS OF DRIZZLE DEVELOPING
EARLY EACH MORNING...ESPECIALLY ALONG THE BLUE RIDGE AND THE EASTERN
FACES OF OTHER PROMINENT RIDGES. MORNING FOG AND LOW CLOUDS WILL
BURN OFF WITH AFTERNOON HEATING...MAKING FOR PARTLY TO MOSTLY CLOUDY
SKIES DURING EACH AFTERNOON. MAY SEE A FEW SHOWERS DEVELOP EACH
AFTERNOON AND EVENING AS SUBTLE DISTURBANCES RIDE ALONG THE EDGE OF
THE UPPER RIDGE. SHOWER ACTIVITY MAY BE ENHANCED BY THE OROGRAPHIC
LIFT OF EASTERLY FLOW INTO THE MOUNTAINS...BUT OTHERWISE DO NOT SEE
ANY SPECIFIC FEATURE THAT WILL CAUSE ORGANIZED RAINFALL. ANY SHOWER
ACTIVITY WILL DIMINISH DURING LATE EVENING AS DAYTIME HEATING
ENDS...WITH A REDEVELOPMENT OF LOW CLOUDS AND PATCHY FOG/DRIZZLE
LATER IN THE OVERNIGHT.

THE FLOW OFF OF THE ATLANTIC WILL MAINTAIN SLIGHTLY COOL CONDITIONS
FOR MUCH OF THE AREA...WITH AFTERNOON HIGHS SOME 3 TO 5 DEGREES
BELOW NORMAL EACH DAY...GENERALLY REACHING INTO THE MID TO UPPER
60S. PORTIONS OF THE MOUNTAIN EMPIRE AND SOUTHEAST WEST VIRGINIA...
LOCATIONS AT THE VERY EDGE OF THE HIGH PRESSURE WEDGE...ARE EXPECTED
TO BE CLOSE TO NORMAL FOR HIGHS. MORNING LOWS WILL BE IN THE UPPER
40S TO LOW 50S WEDNESDAY AND THURSDAY NIGHT...BUT WILL DIP COOLER
FRIDAY NIGHT AS THE UPPER RIDGE BEGINS TO BREAK DOWN...AND WILL
THEREFORE FALL INTO THE LOW 40S NORTH TO UPPER 40S SOUTH.

&&

.LONG TERM /SATURDAY THROUGH MONDAY/...
AS OF 258 PM EDT MONDAY...

THE GYRE OVER THE CANADIAN MARITIMES WILL EVENTUALLY ERODE THE OMEGA
BLOCK INTO A REX...AS A PIECE OF THIS VORTEX WILL ACTUALLY BREAK
FREE AND HEAD SOUTHWEST. NONETHELESS EXPECT SIMILAR WEDGE CONDS
THROUGH THE WEEKEND. THE ECMWF/GFS HAVE HAD A DIFFICULT TIME
RESOLVING AN UPPER DISTURBANCE CROSSING THE LOWER MISSISSIPPI RIVER
VALLEY EARLY NEXT WEEK. THE 12Z GFS WANTS TO BRING THIS SYSTEM
ACROSS THE MOUNTAINS AND INTO THE MID ATLANTIC...WHEREAS THE ECMWF
IS MORE NORTH AND WEST WITH ITS TRACK. IT DOES APPEAR AS THOUGH THIS
STRONG UPPER LOW WILL FINALLY BREAK DOWN THE STRONG UPPER
HIGH...LEADING TO A WARMUP WITH MORE SUNSHINE FINALLY NEXT WEEK.

&&

.AVIATION /14Z TUESDAY THROUGH SATURDAY/...
AS OF 740 AM EDT TUESDAY...

POOR AVIATION CONDITIONS EXPECTED TO PERSIST THROUGH TAF VALID
PERIOD AS A MID-ATLANTIC SFC HIGH PERSISTS WITH A COOL...EASTERLY
MARITIME FLOW INTO THE CWA. ANY EROSION OF THE WEDGE DURING
DIURNAL HEATING WILL FILL BACK IN OVERNIGHT...WITH PERHAPS EVEN A
BETTER SURGE TONIGHT AS COMPARED TO THIS MORNING AS THE CRUX OF
THE MARITIME AIR MASS SETTLES ACROSS THE REGION. EXPECT IFR-LIFR
CIGS AND MOSTLY MVFR-OCCASIONALLY IFR VSBYS TO PREVAIL AT MANY OF
THE TAF SITES THROUGH MID-MORNING...WITH IMPROVEMENT ONLY TO MVFR
CIGS AT BEST 15Z-04Z. VSBYS SHOULD IMPROVE TO VFR AT MOST SITES AS
THE CIGS LIFT INTO THE MVFR CATEGORY...BEFORE CONDITIONS
DETERIORATE AFTER MIDNIGHT BACK TO IFR-LIFR CIGS AND MVFR-IFR
VSBYS AGAIN. THE EXCEPTION WILL BE BLF...WHICH WILL REMAIN ON THE
PERIPHERY OF THE WEDGE AND WILL HAVE LESS POTENTIAL FOR IFR/LIFR
CIGS/VSBYS THROUGH THIS TAF VALID PERIOD. WINDS WILL REMAIN NE-E
5-8KTS THROUGH THE TAF VALID PERIOD...WITH LOW END GUSTS POSSIBLE
15Z-22Z LYH AND DAN. ANY TSRA SHOULD REMAIN WEST OF THE CWA AND
NOT AFFECT ANY OF THE RNK TAF SITES.

EXTENDED AVIATION DISCUSSION...PERHAPS SLIGHTLY IMPROVED AVIATION
CONDITIONS BY THE END OF THE WEEK INTO THE FIRST HALF OF THE
WEEKEND WITH ENOUGH DRYING FROM THE NE TO ALLOW FOR A BRIEF RETURN
TO VFR FOR THURSDAY INTO FRIDAY...IF THE SFC AND UPPER HIGH CAN
MOVE OVERHEAD. THIS WILL SHUNT THE DEEPER MOISTURE INTO THE SE
STATES. RETURN FLOW SHOULD BRING MOISTURE BACK NORTH BY SATURDAY
OR SUNDAY AHEAD OF A VERY SLOW MOVING OCCLUDED FRONT/CLOSED UPPER
LOW TO THE WEST. THIS MAY RESULT IN A RETURN OR CONTINUATION OF
MVFR CIGS...BUT CONSIDERABLE MODEL RUN-TO-RUN CONSISTENCY DOES NOT
ALLOW FOR MUCH RELIABILITY IN FORECAST CONDITIONS THAT FAR OUT AT
THIS TIME.

&&

.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.

&&

$$
SYNOPSIS...PW
NEAR TERM...PW
SHORT TERM...NF
LONG TERM...KM
AVIATION...RAB




AREA FORECAST DISCUSSION

NWS LA CROSSE WI

 616 AM CDT TUE APR 30 2013

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 429 AM CDT TUE APR 30 2013

MAIN FORECAST CONCERNS THROUGH THIS AFTERNOON ARE ON SHOWERS AND
THUNDERSTORMS...WITH THE POTENTIAL FOR SEVERE THUNDERSTORMS ALONG A
COLD FRONT THIS AFTERNOON INTO THIS EVENING. THE FOCUS THEN QUICKLY
TURNS TO A PROLONGED PERIOD OF RAINFALL STARTING LATE TONIGHT AND
CONTINUING THROUGH FRIDAY. THERE COULD ALSO BE SIGNIFICANT SNOW
ACCUMULATIONS FROM WEDNESDAY NIGHT THROUGH THURSDAY.

SURFACE LOW PRESSURE OVER NORTHEAST SOUTH DAKOTA WILL LIFT NORTHEAST
INTO NORTHERN MINNESOTA EARLY THIS MORNING PULLING A WARM FRONT
NORTH ACROSS THE FORECAST AREA. A STRONG LOW LEVEL JET...FOCUSED INTO
NORTHEAST IOWA INTO SOUTHWEST WISCONSIN...WILL CONTINUE TO FUEL
SHOWERS AND THUNDERSTORMS EARLY IN THE MORNING...THEN THIS ACTIVITY
SHOULD QUICKLY PUSH INTO SOUTH CENTRAL WISCONSIN. AN UNSEASONABLY
WARM AIRMASS MOVES INTO THE FORECAST AREA IN THE WAKE OF THE WARM
FRONT WITH TEMPERATURES SOARING INTO THE MID 70S TO LOWER 80S. THESE
WARM TEMPERATURES WILL BE SHORT LIVED AS A COLD PUSHES INTO EASTERN
MINNESOTA/CENTRAL IOWA LATE THIS MORNING. THE FRONT WILL GRADUALLY
SLIDE SOUTHEAST ACROSS THE FORECAST AREA THIS AFTERNOON. THE MAIN
CONCERN ALONG THE FRONT TODAY IS WHEN WILL THE CONVECTION FIRE ALONG
IT. THERE IS A STRONG CAP THAT MOVES INTO THE FORECAST AREA THIS
MORNING IN THE WAKE OF THE WARM FRONT...WITH MLCIN VALUES OF 300
J/KG. THE CAP FINALLY ERODES AHEAD OF THE FRONT BY MID AFTERNOON. BY
THEN...THE FRONT LOOKS TO BE POSITIONED FROM NORTH CENTRAL WISCONSIN
STRETCHING SOUTHWEST INTO NORTHEAST IOWA. LOCATIONS ACROSS NORTHEAST
IOWA...SOUTHWEST AND CENTRAL WISCONSIN LOOK TO HAVE THE HIGHEST
CHANCES OF SEEING THUNDERSTORMS THIS AFTERNOON. THE BEST SHEAR FOR
SEVERE THUNDERSTORMS LAGS RIGHT ALONG TO JUST BEHIND THE FRONT.
SURFACE BASED CAPE VALUES CLIMB TO AROUND 1100 J/KG. IF THE STORMS
FIRE...THERE IS THE POTENTIAL FOR THEM TO BECOME SEVERE WITH LARGE
HAIL AND DAMAGING WINDS. AS THIS FRONT IS DRIFTING SOUTHEAST TODAY A
POTENT TROUGH IS DIGGING ACROSS THE NORTHWEST CONUS INTO THE
DAKOTAS. AN IMPRESSIVE FRONTOGENESIS ZONE STARTS TO TAKE SHAPE EARLY
THIS EVENING. FORECAST MODEL CROSS SECTIONS RUNNING FROM SOUTHEAST
TO NORTHWEST ACROSS THIS FRONTOGENESIS ZONE SHOW IT STRETCHING FROM
NEAR THE SURFACE OVER NORTHERN ILLINOIS THEN SLOPING BACK TO THE
NORTHWEST THROUGH CENTRAL MINNESOTA. THIS ZONE IS VERY
DEEP...EXTENDING ALL THE WAY THROUGH 500 MB. ALSO...NEGATIVE EPV IS
LOCATED JUST ABOVE THE FRONTOGENESIS. A VERY PRONOUNCED AND WIDE
BAND OF PRECIPITATION WILL DEVELOP ACROSS THE AREA TONIGHT.
LOCATIONS WEST OF HIGHWAY 63...OVER NORTHEAST IOWA AND SOUTHEAST
MINNESOTA...WILL SEE THE STEADIER RAINS MOVE IN AROUND OR SHORTLY
AFTER MIDNIGHT THEN THE BAND WILL SPREAD WEST THROUGH THE OVERNIGHT
AND IMPACTING ALL OF SOUTHEAST MINNESOTA...NORTHEAST IOWA AND MUCH
OF WESTERN WISCONSIN.

.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 429 AM CDT TUE APR 30 2013

THE TROUGH CONTINUES TO DIG SOUTHWARD ON WEDNESDAY AND THE
IMPRESSIVE FRONTOGENESIS ZONES REMAINS ANCHORED OVER THE AREA WITH
RAINFALL CONTINUING. THE HIGHEST RAINFALL AMOUNTS ARE EXPECTED TO
FALL ACROSS NORTHEAST IOWA...SOUTHEAST MINNESOTA...AND WEST CENTRAL
INTO NORTH CENTRAL WISCONSIN. FORECAST MODELS ARE SUGGESTING
RAINFALL AMOUNTS OF 1/2 TO AROUND 3/4 INCH ARE POSSIBLE BY WEDNESDAY
AFTERNOON. THE HIGHEST AMOUNTS APPEAR FOCUSED ALONG AND WEST OF
INTERSTATE 35. RAIN WILL CONTINUE INTO WEDNESDAY NIGHT. A SWITCH
OVER TO SNOW IS EXPECTED LATE AS COLDER AIR WRAPS INTO THE SYSTEM
FROM THE NORTH AS THE TROUGH DEEPENS. THE SNOW LOOKS TO CONTINUE
INTO THURSDAY MORNING. SNOW ACCUMULATIONS OF 2 TO 4 INCHES ARE
LIKELY WEST OF A LINE FROM CHARLES CITY TO WINONA TO MEDFORD. THERE
IS THE POTENTIAL FOR A SWATH OF 5 TO 8 INCHES OF SNOW NEAR THE
INTERSTATE 35 CORRIDOR...POSSIBLY EDGING INTO
WABASHA...OLMSTED...DODGE...MOWER AND MITCHELL COUNTIES. MOST OF THE
ACCUMULATION WOULD BE ON GRASSY SURFACES WITH MAINLY A SLUSHY
ACCUMULATION ON AREA ROADS. THE BAND OF RAIN AND SNOW IS EXPECTED TO
EDGE EAST THROUGH THE DAY ON THURSDAY AND SWITCH OVER TO ALL RAIN BY
MIDDAY. IT IS IMPORTANT TO NOTE THERE REMAINS CONSIDERABLE
UNCERTAINTY ON THE EXACT PLACEMENT OF THE RAIN/SNOW LINE. IF THE LOW
TRACKS SLIGHTLY FURTHER WEST...THE FORECAST AREA COULD SEE ALL
RAIN.  BY THE TIME THE PRECIP FINALLY WINDS DOWN LATE FRIDAY
RAINFALL AMOUNTS OF 2 TO 3 INCHES APPEAR LIKELY ACROSS PORTIONS OF
NORTHEAST IOWA...AND MUCH OF SOUTHEAST MINNESOTA INTO WEST CENTRAL
WISCONSIN. THESE RAINFALL AMOUNTS WOULD RESULT IN RISES ON AREA
RIVERS AND POSSIBLE FLOODING. LOCATIONS ACROSS SOUTHWEST INTO
CENTRAL WISCONSIN COULD SEE RAINFALL AMOUNTS OF 1 TO 2 INCHES...WITH
LOCALLY HIGHER AMOUNTS POSSIBLE. UNSEASONABLY COOL TEMPERATURES ARE IN
STORE FOR THE AREA AS THIS STORM SYSTEM IMPACTS THE REGION...WITH
HIGHS ON THURSDAY RANGING FROM THE MID MID 30S ACROSS SOUTHEAST
MINNESOTA TO THE UPPER 40S OVER CENTRAL WISCONSIN. THE  TROUGH CLOSES
INTO A CUTOFF LOW FRIDAY INTO SATURDAY. FORECAST MODELS ARE SHOWING
DIFFERING SOLUTIONS WITH THE TRACK OF THE CUTOFF LOW. THE ECMWF
PLACES THE CENTER OF THE LOW OVER WESTERN IOWA/EASTERN NEBRASKA ON
FRIDAY...THEN LIFTS IT NORTH INTO NORTHERN MINNESOTA SATURDAY INTO
SUNDAY. THE GFS TAKES THE LOW WAY TO THE SOUTH AND CUTS IT OFF OVER
NORTHERN ARKANSAS. THE GEM OFFERS A SOLUTION IN BETWEEN THE ECMWF
AND GFS...CUTTING THE LOW OFF OVER NORTHERN MISSOURI AND LIFTING IT
NORTHEAST INTO THE UPPER MISSISSIPPI RIVER VALLEY  LATE SATURDAY
THROUGH SUNDAY. WILL LEAN TOWARD A MODEL CONSENSUS BLEND SATURDAY
INTO MONDAY...KEEPING CHANCES FOR RAIN ACROSS THE FORECAST AREA.
TEMPERATURES WILL GRADUALLY RECOVER THIS WEEKEND WITH HIGHS ON
SUNDAY EDGING INTO THE MID TO UPPER 50S.

&&

.AVIATION...TODAY AND TONIGHT
616 AM CDT TUE APR 30 2013

A WARM FRONT HAS LIFTED NORTH THROUGH BOTH TAF SITES WITH THE
WINDS COMING AROUND TO THE SOUTH. SECONDARY BAND OF THUNDERSTORMS
FORMED ALONG THE FRONT BUT HAVE ALREADY MOVED PAST KLSE AND DO NOT
PLAN TO INCLUDE THESE IN THE 12Z TAF. EVEN THOUGH THE WARM FRONT
HAS MOVE THROUGH...VWP WINDS FROM THE KARX RADAR STILL SHOWS LOW
LEVEL WIND SHEAR IS OCCURRING WITH 45 KNOTS AT 2000 FEET. BOTH THE
30.06Z NAM AND 30.09Z RAP SHOW THIS CONTINUING THROUGH MID MORNING
BEFORE THE LOW LEVEL JET STARTS TO DISSIPATE ALLOWING THE WINDS
ALOFT TO DIMINISH. AS THE COLD FRONT APPROACHES FROM THE
WEST...GOOD MIXING AHEAD OF IT SHOULD PRODUCE GUSTY SOUTHWEST
WINDS AT BOTH SITES. THE COLD FRONT SHOULD PASS THROUGH KRST EARLY
THIS AFTERNOON SWITCHING THE WINDS AROUND TO THE WEST/NORTHWEST
AND THEN GOING THROUGH KLSE AROUND 00Z OR SO. SCATTERED SHOWERS
AND STORMS SHOULD OCCUR ALONG THE FRONT BUT EXPECTING THE COVERAGE
TO BE TOO LIMITED TO EVEN INCLUDE A VCTS AT THIS TIME FOR EITHER
SITE. THE FRONTOGENESIS GETS GOING IN THE 850-700 MB LAYER THIS
EVENING BEHIND THE FRONT WHICH SHOULD ALLOW SOME LIGHT RAIN TO
FORM AND SPREAD OVER BOTH TAF SITES DURING THE EVENING. THIS
FRONTOGENESIS THEN LOOKS TO TEMPORARILY WEAKEN OVERNIGHT ALLOWING
THE LIGHT RAIN TO END FOR A WHILE. IN GENERAL...VFR CONDITIONS
EXPECTED THROUGH THE PERIOD.

&&

.HYDROLOGY...
ISSUED AT 429 AM CDT TUE APR 30 2013

HEAVY PRECIPITATION RATES ARE EXPECTED WEDNESDAY INTO FRIDAY AS A
STORM SYSTEM STALLS ACROSS THE REGION. IF THE PRECIPITATION FALLS
MAINLY AS RAIN...THERE IS THE POTENTIAL FOR 2 TO 3 INCHES TO FALL BY
FRIDAY...PARTICULARLY IN SOUTHEAST MINNESOTA AND NORTHEAST IOWA.
THIS ADDITIONAL RAINFALL WILL LEAD TO RISES AND POSSIBLE FLOODING ON
LOCAL RIVERS AND STREAMS WHICH ARE ALREADY SOME WHAT HIGH DUE TO
RECENT PRECIPITATION AND THE SPRING SNOW MELT. LOCATIONS ACROSS
WESTERN INTO CENTRAL WISCONSIN COULD SEE 1 TO 2 INCHES OF RAINFALL
OUT OF THIS SYSTEM. THERE REMAINS UNCERTAINTY ON PLACEMENT OF THE
HEAVIEST BAND OF RAINFALL. AT THIS TIME IT APPEARS THAT PORTIONS OF
WEST CENTRAL WISCONSIN...SOUTHEAST MINNESOTA...AND NORTHEAST IOWA
WILL SEE THE HIGHEST RAINFALL AMOUNTS.

&&

.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.

&&

$$

SHORT TERM...WETENKAMP
LONG TERM...WETENKAMP
AVIATION...04
HYDROLOGY...WETENKAMP








AREA FORECAST DISCUSSION

NWS LINCOLN IL

 224 PM CDT TUE APR 30 2013

.DISCUSSION...
ISSUED 205 PM CDT TUE APR 30 2013

WARM AND DRY CONDITIONS TO HOLD THRU WED NIGHT WITH INCREASING
RAIN CHANCES DURING THE DAY THURSDAY...AND ESPECIALLY THURSDAY
NIGHT THROUGH FRIDAY NIGHT AS AN UPPER LEVEL SYSTEM CLOSES OFF
OVER THE SOUTHERN PLAINS FRIDAY AND SLOWLY MOVES NORTHEAST THRU
THE MIDWEST THIS WEEKEND.

SHORT TERM...TONIGHT THROUGH FRIDAY NIGHT

NO SIGNIFICANT MODEL DIFFERENCES SEEN THRU THURSDAY MORNING AS THE
FRONTAL BOUNDARY THAT IS OUT OVER WEST CENTRAL IOWA WILL ONLY SLOWLY
EDGE EAST OVER THE NEXT 36 TO 48 HOURS AND NOT GET INTO OUR AREA
UNTIL THURSDAY. UNTIL THEN...A MILD SOUTHERLY FLOW WILL CONTINUE THRU
AT LEAST THURSDAY MORNING MOST AREAS. MODELS HAVE BEEN CONSISTENTLY
SHOWING A COOLING TREND AT 850 MB TOMORROW...ALBEIT 2 TO 3 DEGREES...BUT
THAT`S ENOUGH TO SUPPORT TEMPS A FEW DEGREES COOLER THAN THIS AFTERNOON`S
HIGH TEMPS. WENT WITH THE WARMER GUID THURSDAY BASED ON THE SLOWER FRONTAL
MOVEMENT WITH THE COLDEST TEMPS ALOFT CLOSE TO THE CLOSED LOW AT 500
MB...WHICH BY FRIDAY NIGHT WILL BE OVER SOUTH-CENTRAL MISSOUR.

MODELS CONTINUE TO INDICATE MOST OF THE PRECIP TO BE POST FRONTAL...AND
BASED ON THE SLOWER TIMING OF THE BOUNDARY INTO THE FORECAST AREA ON
THURSDAY...WILL BUMP TEMPS UP AND HAVE THE HIGHEST POPS STARTING THU
AFTERNOON AND ESPECIALLY THU NIGHT. BEST CHANCE FOR ANY CONVECTION
LOOK TO BE RIGHT ALONG OR IMMEDIATELY BEHIND THE FRONTAL BOUNDARY
WITH MOST OF THE FORECAST SOUNDINGS SHOWING LIMITED SURFACE BASE/MU
CAPES. FORECAST SOUNDINGS SUGGEST THE DEEPEST MOISTURE OVER OUR AREA
FRIDAY INTO FRIDAY NIGHT RESULTING IN OCCASIONAL SHOWERS...POSSIBLY
SOME THUNDER...ESPECIALLY OVER THE EAST CLOSEST TO THE BOUNDARY.

LONG TERM...SATURDAY THROUGH TUESDAY

THE UPPER LOW FORECAST TO TRACK SLOWLY NNE ACRS MISSOURI SATURDAY
AND SUNDAY...KEEPING RAIN CHANCES GOING THRU THE WEEKEND WITH SLIGHTLY
COOLER TEMPERATURES...ESPECIALLY ON SUNDAY WHEN WE WILL BE CLOSEST
TO THE UPPER LOW. AS THE LOW DRIFTS FURTHER NNE INTO NORTHERN IL BY
LATE SUNDAY NIGHT OR MONDAY...IT WOULD APPEAR OUR PRECIP CHANCES
WOULD BECOME MORE DIURNAL IN NATURE WITH THE BETTER CHANCES DURING
PEAK HEATING IN THE AFTERNOON AND EARLY EVENING...AND THEN A LULL/OR
DROP OFF IN POPS AT NIGHT. WILL TRY TO TREND IN THAT DIRECTION BASED
ON THE FURTHER NORTH FORECAST FROM THE ECMWF AND CANADIAN MODELS.

AS FAR AS RAINFALL AMOUNTS ARE CONCERNED...IT APPEARS THE PROBABILITY
FOR THE MOST WIDESPREAD RAINS WILL BE HIGHEST LATER THURSDAY NIGHT
INTO FRIDAY NIGHT WITH QPF VALUES OF 1-2 INCHES POSSIBLE. WILL HAVE
TO SEE HOW MUCH...IF ANY...THE MOISTURE TRANSPORT WILL BE TAKEN UP
BY AN UPPER LEVEL LOW AND SFC WAVE ALONG THE GULF COAST FRIDAY AND
SATURDAY. SEE THE HYDROLOGY SECTION BELOW FOR SOME PRELIMINARY INFO
ON HOW THIS RAINFALL MAY AFFECT SOME OF THE RIVERS IN OUR AREA.

SMITH
&&

.AVIATION...
ISSUED 1235 PM CDT TUE APR 30 2013

VFR CONDITIONS WILL CONTINUE THROUGH THE ENTIRE TAF PERIOD IN
CENTRAL AND EAST ILLINOIS.

THE MAIN CONCERN FOR TODAY WILL BE SURFACE WIND GUSTS WITH THE
INCREASING GRADIENT IN WESTERN AND CENTRAL ILLINOIS AHEAD OF A
SLOW MOVING COLD FRONT IN CENTRAL IOWA. BUFKIT MOMENTUM TRANSFER
FROM THE NAM AND SURFACE GUST FORECASTS FROM THE HRRR AND RAPID
REFRESH MODELS ALL INDICATE THAT THE HIGHEST POTENTIAL FOR WIND
GUSTS WILL BE ALONG AND WEST OF I-55 WHERE THE BEST MIXING AND
WARMEST TEMPERATURES ARE EXPECTED. AS A RESULT...WILL REMOVE GUSTS
FROM THE TAFS FOR KDEC/KCMI. THE WIND WILL SETTLE DOWN JUST BEFORE
SUNSET AS THE LOWER ATMOSPHERE BEGINS TO DECOUPLE AND THE
NIGHTTIME INVERSION SETS UP.

VERY LITTLE IN THE WAY OF CLOUD COVER IS ANTICIPATED WITH DRY LOW
LEVELS OF THE ATMOSPHERE AND CONVECTIVE TEMPS CLOSE TO 90. ONLY
SOME SCATTERED HIGH CLOUDS ARE EXPECTED AT TIMES THIS AFTERNOON
AND TONIGHT...WITH A BIT OF CUMULUS ANTICIPATED LATER WEDNESDAY
MORNING AS LOW LEVEL MOISTURE JUST STARTS TO INCREASE.

MILLER
&&

.HYDROLOGY...
ISSUED 205 PM CDT TUE APR 30 2013

CURRENT INDICATIONS SUGGEST THAT BASED ON A BASIN AVERAGE OF 1-1.5"
OF RAIN INTO SATURDAY...THE ILLINOIS BASIN WOULD NOT SEE MUCH OF A
RESPONSE OTHER THAN TO SLOW DOWN THE RATE OF FALL AT OUR FORECAST
SITES INTO EARLY NEXT WEEK. ALONG THE SPOON AND SANGAMON BASINS...WE
COULD SEE RIVER LEVELS RISE IF WE DID RECEIVE THIS MUCH RAINFALL...BUT
IT APPEARS MOST AREAS WILL REMAIN BELOW FLOOD STAGE INTO EARLY NEXT
WEEK. STILL SOME UNCERTAINTY WITH RESPECT TO THE TRACK OF THE UPPER
LEVEL SYSTEM AND FRONTAL BOUNDARY ACROSS OUR AREA LATE IN THE WEEK
AND INTO THE WEEKEND...AS A RESULT...THE AXIS OF HEAVIEST RAINS WILL
NEED TO BE ADJUSTED SOME AS THE STORM SYSTEM DRAWS CLOSER TO THE
MIDWEST.

SMITH
&&

.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$





AREA FORECAST DISCUSSION

NWS LINCOLN IL

 1235 PM CDT TUE APR 30 2013

.DISCUSSION...
ISSUED 1055 AM CDT TUE APR 30 2013

ONLY MADE MINOR TWEAKS TO THE FORECAST/GRIDS FOR THIS
AFTERNOON...MAINLY TO BUMP UP TEMPS A COUPLE OF DEGREES IN WEST
CENTRAL IL. MORNING SOUNDINGS AROUND THE MIDWEST INDICATED THAT
WITH PLENTY OF MIXING...WHICH IS ALREADY OCCURRING...THERE IS
ENOUGH WARM AIR IN THE LOW LEVELS TO ALLOW TEMPS TO CLIMB WELL
INTO THE LOWER TO MIDDLE 80S.

THE MIXING WILL ALSO RESULT IN ANOTHER DAY OF GUSTY SOUTH WINDS.
ALSO TWEAKED THE GUSTS UP A BIT FOR THIS AFTERNOON. OTHERWISE...
DRY WILL BE THE MAIN WEATHER WORD FOR TODAY



&&

.AVIATION...
ISSUED 1235 PM CDT TUE APR 30 2013

VFR CONDITIONS WILL CONTINUE THROUGH THE ENTIRE TAF PERIOD IN
CENTRAL AND EAST ILLINOIS.

THE MAIN CONCERN FOR TODAY WILL BE SURFACE WIND GUSTS WITH THE
INCREASING GRADIENT IN WESTERN AND CENTRAL ILLINOIS AHEAD OF A
SLOW MOVING COLD FRONT IN CENTRAL IOWA. BUFKIT MOMENTUM TRANSFER
FROM THE NAM AND SURFACE GUST FORECASTS FROM THE HRRR AND RAPID
REFRESH MODELS ALL INDICATE THAT THE HIGHEST POTENTIAL FOR WIND
GUSTS WILL BE ALONG AND WEST OF I-55 WHERE THE BEST MIXING AND
WARMEST TEMPERATURES ARE EXPECTED. AS A RESULT...WILL REMOVE GUSTS
FROM THE TAFS FOR KDEC/KCMI. THE WIND WILL SETTLE DOWN JUST BEFORE
SUNSET AS THE LOWER ATMOSPHERE BEGINS TO DECOUPLE AND THE
NIGHTTIME INVERSION SETS UP.

VERY LITTLE IN THE WAY OF CLOUD COVER IS ANTICIPATED WITH DRY LOW
LEVELS OF THE ATMOSPHERE AND CONVECTIVE TEMPS CLOSE TO 90. ONLY
SOME SCATTERED HIGH CLOUDS ARE EXPECTED AT TIMES THIS AFTERNOON
AND TONIGHT...WITH A BIT OF CUMULUS ANTICIPATED LATER WEDNESDAY
MORNING AS LOW LEVEL MOISTURE JUST STARTS TO INCREASE.

MILLER
&&

.PREV DISCUSSION...
ISSUED 321 AM CDT TUE APR 30 2013

MAIN CONCERN THIS FORECAST PACKAGE WILL BE ONSET OF PCPN LATER
THIS WEEK...ASSOCIATED WITH THE FRONTAL SYSTEM THAT IS SLOWLY
MOVING INTO THE AREA. MODELS SEEM SIMILAR WITH TIMING OF THE
FRONT...BUT DIFFER WITH WHEN PCPN WILL BEGIN IN THE AREA. ALL
MODELS HAVE MOST OF THE PCPN POST-FRONTAL. HOWEVER...SOME HAVE
SOME LIGHT PCPN AHEAD OF THE FRONT. ALL MODELS AGREE ON THE
OVERALL UPPER LEVEL PATTERN WITH A TROUGH DEVELOPING IN THE PLAINS
TOWARD END OF THE WEEK...BUT THEN DIFFER IN THE EXTENDED WITH
LOCATION AND MOVEMENT OF THE CUTOFF LOW THAT ALL MODELS DEVELOP.

SHORT TERM...TODAY THROUGH THURSDAY NIGHT

MODELS SIMILAR WITH FRONT THROUGH ABOUT 48HRS ONLY...BUT THEN GFS
BECOMES QUICKER THAN NAM/ECMWF. THEN BY THURSDAY THE NAM BECOMES
THE QUICKEST AND THE ECMWF IS SLOWEST. THESE DIFFERENCES GET
REFLECTED ON WHEN PCPN STARTS. BELIEVE SLOWEST SOLUTION IS
BEST...BUT HAVE TO BLEND WITH SURROUNDING OFFICES SO WENT WITH
JUST CHC POPS FOR THURSDAY MORNING...AND THEN LIKELY IN THE WEST
FOR THE AFTERNOON. PRIOR TO THUR CONDITIONS WILL BE DRY FOR TODAY
THROUGH WED AND THEN A CHC OF PCPN NORTHWEST OF THE IL RIVER FOR
WED NIGHT. ALL MODELS AGREE PCPN WILL BE LIKELY FOR THUR NIGHT.
AHEAD OF THE FRONT...PCPN TYPE LOOKS TO BE THUNDERSTORMS BUT ONCE
FRONT MOVES THROUGH THE AREA STORMS SHOULD BECOME MORE ISOLATED
AND MAIN PCPN TYPE WILL BE SHOWERS. RAIN SHOULD BE MODERATE AS
WELL GIVEN THE SLOW NATURE OF THE PCPN OVER THE AREA THROUGH THE
PERIOD.

TEMPS WILL BE QUITE WARM TODAY AND TOMORROW AS CWA SITS IN THE
WARM SECTOR. WINDS COULD ALSO BE BREEZY AGAIN TODAY...AS
YESTERDAY. ONCE PCPN AND CLOUD COVER MOVES INTO THE AREA TEMPS
WILL THEN COOL...DROPPING TO BELOW NORMAL FOR EARLY MAY.

LONG TERM...FRIDAY THROUGH MONDAY

WITH EXTENDED MODELS DIFFERING ON HOW THE SFC FEATURES WILL
PROGRESS AFTER THURSDAY NIGHT AND DIFFER ON WHEN AND WHERE THE
UPPER LEVEL LOW WILL MOVE TO...HAVE DECIDED TO JUST FOLLOW THE
BLENDED MODEL FORECAST. THIS FORECAST KEEPS A CHC OF PCPN IN THE
FORECAST THROUGH MONDAY. ALL PCPN SHOULD BE IN THE FORM OF
SHOWERS.

TEMPS WILL REMAIN ON THE COOL SIDE WITH CONTINUED PCPN AND SOME
CLOUD COVER THROUGH THE PERIOD. IN ADDITION...WITH THE UPPER LEVEL
SYSTEM BEING EITHER OVER US OR NEAR US INTO THE WEEKEND...COOL MID
LEVEL TEMPS WILL ALSO HELP TO KEEP US ON THE COOL SIDE FOR
AFTERNOON HIGHS. TEMPS COULD BEGIN TO WARM BACK TO NORMAL BY
BEGINNING OF NEXT WEEK...BUT ITS TOO SOON TO BE OPTIMISTIC WITH
THAT AS MORE PCPN IS POSSIBLE THE FIRST PART OF NEXT WEEK.


&&

.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$








AREA FORECAST DISCUSSION

NWS TOPEKA KS

 327 PM CDT TUE APR 30 2013

.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 327 PM CDT TUE APR 30 2013

20Z WATER VAPOR IMAGERY SHOWS BROAD CYCLONIC FLOW ACROSS THE
WESTERN TWO THIRDS OF THE COUNTY WITH ONE SHORTWAVE LIFTING NORTH
INTO CANADA AND A SECOND SHORTWAVE DIGGING INTO NORTHERN UT. AT
THE SURFACE...A FRONTAL BOUNDARY HAS REMAINED STATIONARY FROM
SOUTHWESTERN KS INTO SOUTHEASTERN NEB...CROSSING CLOUD AND
REPUBLIC COUNTIES. LOW LEVEL MOIST CONVERGENCE ALONG THIS FRONT
HAS ALLOWED A STRATOCU FIELD TO DEVELOP ALONG THE FRONT.

FOR THIS EVENING...MODELS SHOW LITTLE IF ANY LARGE SCALE FORCING FOR
CONVECTION. SO IF THUNDERSTORMS ARE GOING TO DEVELOP...IT WILL
LIKELY BE DUE TO PERSISTENT CONVERGENCE ALONG THE FRONT ALONG WITH
DAYTIME HEATING WEAKENING THE CAPPING INVERSION. 19Z LAPS ANALYSIS
SUGGESTS THERE REMAINS SOME INHIBITION TO A SURFACE PARCEL...BUT CIN
IS ONLY AROUND 20 J/KG NEAR THE NEB STATE LINE. HIGH RES MODELS HAVE
BEEN FAIRLY CONSISTENT IN DEPICTING CONVECTION FORMING ALONG THE
FRONT BETWEEN 23Z AND 01Z. WHILE DEEP LAYER SHEAR VECTORS IN THE
WARM SECTOR OR RATHER WEAK FOR SUPERCELL STORMS...THERE IS ENOUGH
CAPE THAT STORMS COULD PRODUCE FROM LARGE HAIL OR STRONG WIND GUSTS.
SO WITH THE FRONT EXPECTED TO REMAIN FAIRLY STATIONARY...POPS ARE
CONFINED TO THE NORTHERN COUNTIES. BY LATE TONIGHT AND THROUGH THE
DAY WEDNESDAY AS THE SHORTWAVE OVER THE INTERMOUNTAIN WEST MOVES
CLOSER TO THE PLAINS...COLD AIR ADVECTION INCREASES AND BEGINS TO
PUSH THE FRONT SOUTH INTO CENTRAL AND EVENTUALLY EASTERN KS. MODELS
SHOW DECENT MID LEVEL FRONTOGENESIS WITH THE FRONT AND SATURATED MID
LEVELS WITH MOST OF THE PRECIP OCCURRING POST FRONTAL. WITH THIS IN
MIND HAVE POPS INCREASING LATE TONIGHT AND INTO WEDNESDAY MORNING
WITH CATEGORICAL WORDING. THINK THIS WILL BE MAINLY SHOWERS WITH
SOME EMBEDDED THUNDERSTORMS NEAR THE FRONT. OTHERWISE MID LEVEL
LAPSE RATES REALLY SHALLOW UP BEHIND THE FRONT. MOST AREAS SHOULD
SEE FALLING TEMPS THROUGH THE DAY AS THE FRONT PASSES. LOWS TONIGHT
WILL BE MILD ACROSS MUCH OF THE AREA WITH LOWER 60S EXPECTED. AREAS
ACROSS NORTH CENTRAL KS SHOULD SEE LOWS IN THE 50S WITH THE FRONT
LIKELY SLIPPING SOUTH BEFORE SUNRISE. ACROSS EASTERN KS...HIGHS WILL
HAVE A CHANCE TO WARM INTO THE 70S BEFORE THE FRONT MOVES THROUGH.
THINK TEMPS IN NORTH CENTRAL KS WILL BE NEARLY STEADY OR SLOWING
FALLING THROUGH THE DAY.

.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 327 PM CDT TUE APR 30 2013

FOR THE LATE WEEK PERIODS...CHANGES TO THE PREVIOUS FORECAST ARE NOT
VERY LARGE. THIS ISNT DUE TO HIGH CONFIDENCE...BUT RATHER LOW
CONFIDENCE. MODEL GUIDANCE CONTINUES TO SHOW A WIDE RANGE OF
SOLUTIONS...THOUGH THERE SEEMS TO BE A SLOWER AND SOUTHWARD TREND TO
THE UPPER LOW. THE 0Z ECMWF IS NOW THE FASTER/FARTHER NORTH OUTLIER
WITH THE SYSTEM AND THE 12Z NAM NOT FAR BEHIND. THE LAST FEW GFS
RUNS AND EVERY 12Z GFS ENSEMBLE MEMBER ARE ON THE SOUTH/SLOW END. IF
THIS TREND HOLDS...AND WITH THIS BLOCKING REGIME AND TRACK RECORD
ITS VERY HARD TO SAY IT WILL...THE IMPACTS ON SENSIBLE WEATHER WOULD
BE A SLOWER TRANSITION TO FROZEN PRECIPITATION BUT PROLONGED
PRECIPITATION CHANCES. DID SLOW DOWN THE TRANSITION A BIT...WITH A
COMPLETE CHANGE TO SNOW/SLEET ONLY CONFIDENTLY FORECAST FOR THE
NORTHWEST AND THIS BEING FOR AROUND 12 HOURS AS WARMER AIR STILL MAY
COME IN BY THURSDAY AFTERNOON. IN ADDITION...VERY WARM GROUND TEMPS
AND LOW LAYER TEMPS ON THE WARM SIDE SUGGEST ACCUMULATIONS WILL BE
DIFFICULT ESPECIALLY ON ROADWAYS...AND BACKED DOWN AMOUNTS. LAPSE
RATES WOULD STILL SUGGEST THUNDER POSSIBLE FOR THE SOUTH AND EAST
WEDNESDAY NIGHT...AN NOT LIKELY FAR ENOUGH NORTHWEST FOR A
CONVECTIVE SNOW SITUATION...BUT THE DETAILS WILL NEED TO BE WATCHED
AS THIS PERIOD NEARS. PERSISTENT PRECIP AND THE COLD AIR SHOULD KEEP
DIURNAL RISES RATHER LOW FOR THURSDAY...AND RECORD COOL HIGH VALUES
FOR THE DAY IF NOT THE ENTIRE MONTH OF MAY COULD BE SET. COLDEST
TEMPS STILL SHOULD BE THURSDAY NIGHT...WITH NEAR FREEZING LEVELS
LIKELY. THOUGH NOT COMPLETELY CONFIDENT...WILL KEEP FRIDAY PRECIP
ALL LIQUID. FINALLY...AS WITH WEDNESDAY...WIND SPEEDS WEDNESDAY
NIGHT COULD NEAR ADVISORY LEVELS...AND IF THEY CAN OCCUR WITH
FALLING SNOW...A WINTER WEATHER HAZARD COULD PRESENT ITSELF VIA LOW
VISIBILITIES.

FOR THE WEEKEND...WILL KEEP MODERATE PRECIP CHANCES GOING...
EMPHASIZING THE NORTHEAST AHEAD OF THE MORE LIKELY LOCATION OF THE
UPPER LOW...WITH CHANCES DIMINISHING WITH TIME. MODIFICATION SHOULD
TAKE HOLD BY EARLY NEXT WEEK WITH RETURN FLOW BRING MODEST
PRECIPITATION CHANCES BACK BY MONDAY NIGHT.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1230 PM CDT TUE APR 30 2013

WITH A SHORTWAVE DIGGING SOUTHEAST INTO THE FOUR CORNERS
REGION...MODELS PROG THE BOUNDARY TO REMAIN NEARLY STATIONARY TO
THE NORTH OF THE TERMINALS. SINCE THERE IS LITTLE FORCING...
CONVERGENCE ALONG THE BOUNDARY WILL BE KEY IN THUNDERSTORM
DEVELOPMENT AND HAVE LEFT ANY MENTION OF TS OUT OF THE TAFS FOR
NOW. MAIN UNCERTAINTY IS WITH TIMING TO FROPA WEDNESDAY. WITH MOST
GUIDANCE INDICATING PRECIP WILL BE MAINLY POST FRONTAL WITH AT
LEAST MVFR CIGS...TIMING THE FRONT WILL BE KEY IN BRINGING LOWER
FLIGHT CONDITIONS INTO THE TERMINALS. HAVE LEANED CLOSER TO THE
HIGHER RES SOLUTIONS OF THE NAM AND AN EXTRAPOLATED RAP FOR THE
FROPA. THIS WOULD BRING THE FRONT THROUGH MHK AROUND 15Z AND
THROUGH TOP/FOE JUST AFTER 18Z WED.

&&

.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...WOLTERS
LONG TERM...65
AVIATION...WOLTERS






AREA FORECAST DISCUSSION

NWS TOPEKA KS

 1230 PM CDT TUE APR 30 2013

.UPDATE...
ISSUED AT 1230 PM CDT TUE APR 30 2013

STRONG MIXING OF THE BOUNDARY LAYER AND GOOD INSOLATION HAVE
ALLOWED TEMPS TO WARM UP A LITTLE QUICKER WITHIN THE KS RIVER
VALLEY. BECAUSE OF THIS HAVE BUMPED UP AFTERNOON HIGHS FROM THE
ABILENE AREA EAST ALONG THE RIVER. STRATOCU FILED HAS DEVELOPED ON
THE WARM SIDE OF THE STATIONARY FRONT. LAPS AND RAP ANALYSIS STILL
SHOW QUITE A BIT OF INHIBITION TO OVERCOME. SO WITH NO DYNAMIC
FORCING TO TRIGGER CONVECTION...WILL NEED TO WAIT UNTIL LATE
AFTERNOON WHEN HEATING HAS LOWERED THE INHIBITION TO ITS MINIMUM
AND SEE IF CONVERGENCE ALONG THE BOUNDARY IS ENOUGH TO FIRE SOME
STORMS. THE LAST FEW HRRR RUNS HAVE BEEN CONSISTENT IN DEVELOPING
CONVECTION NEAR REPUBLIC COUNTY AROUND 00Z.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 352 AM CDT TUE APR 30 2013

THIS MORNING A SHORTWAVE TROUGH WAS MOVING ACROSS THE NORTHERN
PLAINS AND SOUTHERN CANADA. AS THIS FEATURE MOVES EAST NORTHEAST
INTO ONTARIO SUNSET COUNTRY THIS EVENING. THIS WILL PUSH A FRONTAL
BOUNDARY SOUTHEAST TODAY WITH THE FRONT EXPECTED TO EXTEND FROM
NORTHERN IOWA INTO NORTHWEST KANSAS BY 00Z TUESDAY. A STRONG CAP IS
FORECAST AHEAD OF THE BOUNDARY ACROSS NORTH CENTRAL AND NORTHEAST
KANSAS THROUGH LATE AFTERNOON BEFORE ERODING BY 00Z WEDNESDAY. GOOD
CONVERGENCE IS FORECAST ALONG THE BOUNDARY AND 0-6 KM SHEAR OF 40 TO
50 KTS. SURFACED BASED CAPE OF 1500 TO 2000 J/KG IS FORECAST ALONG
AND AHEAD OF THE FRONT. GIVEN THE SHEAR...STEEP LAPSE
RATES...INSTABILITY...CONVERGENCE AND MOISTURE STRONG TO A FEW
SEVERE THUNDERSTORMS ARE POSSIBLE LATE THIS AFTERNOON AND TONIGHT.
MAIN HAZARDS LOOK TO BE HAIL AND WIND. ANOTHER WARM DAY IS EXPECTED
TODAY AS HIGHS WARM BACK INTO THE LOW TO MID 80S.

THE COLD FRONT WILL BE VERY SLOW MOVING TONIGHT AND REACHING ROUGHLY
A SENECA TO ABILENE LINE BY WEDNESDAY MORNING. AS THE LOW LEVEL JET
INCREASES TONIGHT THERE WILL BE GOOD MOISTURE TRANSPORT INTO THE
FRONTAL ZONE...THUS EXPECT THUNDERSTORMS TO REGENERATE ACROSS NORTH
CENTRAL KANSAS LATER TONIGHT. HAVE INCREASED POPS THERE WHERE THE
BEST MOISTURE FLUX CONVERGENCE IS FORECAST. LOWS TONIGHT WILL
CONTINUE TO BE MILD IN THE 60S WITH TEMPS FALLING INTO THE 40S
BEHIND THE FRONT.

53

.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 352 AM CDT TUE APR 30 2013

A DIFFICULT AND NON-CLIMATOLOGICAL FORECAST FOR PORTIONS OF THE MID
AND LONG TERM FORECAST. WILL TRY TO BREAK IT DOWN BY TIME PERIOD AND
ADDRESS VARYING CONFIDENCE LEVELS WITHIN.

OVERALL SYNOPSIS - A DEEP LONG WAVE TROUGH WILL SLOWLY MOVE OVER THE
PLAINS STATES WEDNESDAY AND THURSDAY. AS THIS HAPPENS...A PIECE OF
SHORT WAVE ENERGY WILL DIVE DOWN THE WEST SIDE OF THE MAIN TROUGH
AND INTENSIFY IN THE BASE OF THE LONG WAVE...RESULTING IN A CLOSED
UPPER LOW IN THE CENTRAL PLAINS BY THURSDAY NIGHT. THE STRONG
MERIDIONAL FLOW PATTERN WILL PULL VERY COLD AIR SOUTH INTO MUCH OF
THE GREAT PLAINS...WITH WINTER PRECIPITATION BECOMING A FORECAST
CONCERN. MODEL SOLUTIONS THEN DIVERGE GREATLY BEYOND FRIDAY WITH ONE
MODEL CAMP ALLOWING THE CLOSED LOW TO MOVE NORTHEAST AND BECOME
RE-ABSORBED INTO THE NORTHERN STREAM. THE OTHER CAMP OF MODEL
GUIDANCE KEEPS THE CLOSED LOW ISOLATED AND MEANDERING FROM THE LOWER
MISSOURI RIVER VALLEY INTO THE SOUTHEAST CONUS. WPC...THE MAJORITY
OF GFS ENSEMBLE MEMBERS...AND ECMWF RUNS PRIOR TO THE 00Z RUN TODAY
SUPPORT MAINTAINING THE CLOSED SYSTEM OVER THE PLAINS FOR A LONGER
PERIOD...ALTHOUGH CONFIDENCE IS WELL BELOW AVERAGE.

WEDNESDAY - THE INCOMING TROUGH AND COLD AIR PUSH WILL SEND THE COLD
FRONT SURGING THROUGH THE FORECAST AREA DURING THE DAY ON WEDNESDAY.
TEMPERATURES WILL VARY GREATLY DURING THE DAY...WITH SOME AREAS
SEEING THEIR HIGH DURING THE MORNING HOURS. AMPLE FORCING WITH THE
SYSTEM WILL BRING WIDESPREAD PRECIPITATION TO THE AREA FROM
NORTHWEST TO SOUTHEAST DURING THE DAY. IT IS WORTH NOTING THAT EAST
CENTRAL PARTS OF THE STATE MAY STAY DRY UNTIL VERY LATE IN THE DAY.
THERE WILL BE INSTABILITY PRESENT THROUGHOUT THE DAY...EVEN POST
FRONTALLY...AND EXPECT EMBEDDED THUNDERSTORMS WITHIN THE RAIN. FAR
SOUTHEASTERN PARTS OF THE FORECAST AREA MAY SUSTAIN SURFACE BASED
THUNDERSTORMS PRIOR TO THE FRONTAL PASSAGE DURING THE LATE AFTERNOON
HOURS. IF THE FRONT IS SLOW ENOUGH...A FEW STRONG STORMS WOULD BE
POSSIBLE AHEAD OF IT. OVERALL CONFIDENCE IN EVOLUTION OF WEDNESDAYS
WEATHER IS FAIRLY STRONG.

WEDNESDAY NIGHT AND THURSDAY NIGHT - COLDER AIR WILL CONTINUE TO
ADVECT INTO THE FORECAST AREA THROUGH WEDNESDAY NIGHT. THE COLDER
AIR WILL OVER RUN THE ONGOING PRECIPITATION AS MID AND UPPER LEVEL
FORCING CONTINUES TO BRING ROUNDS OF MODERATE PRECIPITATION THROUGH
THE FORECAST AREA. MODEL FORECAST TEMPERATURE PROFILES SUGGEST THAT
RAIN WILL CHANGE OVER TO SLEET...AND EVENTUALLY SNOW ACROSS MOST IF
NOT ALL OF THE FORECAST AREA BY THURSDAY MORNING. WHILE CLIMATOLOGY
INDICATES THAT THIS IS QUITE RARE...MODEL AGREEMENT IS VERY GOOD AND
THUS FORECAST CONFIDENCE IN PERIODS OF WINTER PRECIPITATION IS
MODERATE TO STRONG...PARTICULARLY WEST AND NORTH OF MANHATTAN. WITH
THIS FORECAST...HAVE INDICATED THAT AS MUCH AS 1 TO 3 INCHES OF
SNOW/SLEET APPEARS POSSIBLE IN NORTH CENTRAL KANSAS WITH LESSER
AMOUNTS TO THE SOUTHEAST. HOWEVER...MUST SAY THAT ANY SNOW
ACCUMULATION WILL BE HIGHLY DEPENDENT UPON THE RATE OF SNOWFALL
GIVEN THE WARM GROUND CONDITIONS...AND THUS THE CONFIDENCE IN ACTUAL
SNOWFALL AMOUNTS IS QUITE LOW. PRECIP TYPE MAY FLUCTUATE THROUGH THE
DAY ON THURSDAY AS WELL OWING TO THE HIGH SUN ANGLE AND POTENTIAL
WARMING OF CLOUD LAYERS...ALONG WITH MORE SUNLIGHT AND HEAT GETTING
THROUGH THE CLOUDS THAN DURING EARLIER MONTHS. THURSDAY NIGHT ALSO
HAS LESS CONFIDENCE IN PRECIP TYPE GIVEN THAT THERE ARE INDICATIONS
OF MINOR WARM ADVECTION...PERHAPS ENOUGH TO CHANGE TO RAIN...AS THE
HEART OF THE TROUGH DRIFTS EAST. SURFACE TEMPERATURES MAY APPROACH
FREEZING BY FRIDAY MORNING.

FRIDAY THROUGH MONDAY - AS PREVIOUSLY MENTIONED...FORECAST
CONFIDENCE GOES WAY DOWN THROUGH THIS PERIOD AS MODEL GUIDANCE IS
STRONGLY DIVERGENT REGARDING EVOLUTION OF THE CLOSED LOW. AT THIS
TIME...DID NOT CHANGE THE PREVIOUS FORECAST MUCH...AND LEANED
SOMEWHAT CLOSELY TO THE 00Z GFS WHICH KEEPS THE UPPER LOW AND
PERIODS OF SHOWERS CLOSELY ASSOCIATED WITH THE FORECAST AREA THROUGH
SUNDAY. HOWEVER...IF A SOLUTION CLOSER TO THE 00Z ECMWF WOULD
VERIFY...DRY AIR WOULD BUILD INTO THE AREA WITH NO PRECIPITATION AND
WARMER TEMPERATURES THROUGH THIS TIME FRAME.

BARJENBRUCH

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1230 PM CDT TUE APR 30 2013

WITH A SHORTWAVE DIGGING SOUTHEAST INTO THE FOUR CORNERS
REGION...MODELS PROG THE BOUNDARY TO REMAIN NEARLY STATIONARY TO
THE NORTH OF THE TERMINALS. SINCE THERE IS LITTLE FORCING...
CONVERGENCE ALONG THE BOUNDARY WILL BE KEY IN THUNDERSTORM
DEVELOPMENT AND HAVE LEFT ANY MENTION OF TS OUT OF THE TAFS FOR
NOW. MAIN UNCERTAINTY IS WITH TIMING TO FROPA WEDNESDAY. WITH MOST
GUIDANCE INDICATING PRECIP WILL BE MAINLY POST FRONTAL WITH AT
LEAST MVFR CIGS...TIMING THE FRONT WILL BE KEY IN BRINGING LOWER
FLIGHT CONDITIONS INTO THE TERMINALS. HAVE LEANED CLOSER TO THE
HIGHER RES SOLUTIONS OF THE NAM AND AN EXTRAPOLATED RAP FOR THE
FROPA. THIS WOULD BRING THE FRONT THROUGH MHK AROUND 15Z AND
THROUGH TOP/FOE JUST AFTER 18Z WED.

&&

.TOP WATCHES/WARNINGS/ADVISORIES...NONE.

&&

$$

UPDATE...WOLTERS
SHORT TERM...53
LONG TERM...BARJENBRUCH
AVIATION...WOLTERS










AREA FORECAST DISCUSSION

NWS MARQUETTE MI

 432 PM EDT TUE APR 30 2013

.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 432 PM EDT TUE APR 30 2013

WV IMAGERY AND RUC ANALYSIS INDICATED A BROAD MID/UPPER LEVEL TROUGH
OVER THE NW CONUS RESULTING IN SW FLOW FROM THE CNTRL PLAINS TO THE
NRN GREAT LAKES. A VIGOROUS SHORTWAVE IN THIS SW FLOW ALOFT WAS
LIFTING NORTH INTO NW ONTARIO.  AT THE SFC...LOW PRES WAS LOCATED
OVER NW ONTARIO WITH A COLD FRONT EXTENDING SOUTH INTO FAR WRN LAKE
SUPERIOR AND NW WI. A WARM FRONT WAS DRAPED ACROSS NCNTRL AND NE WI.
BULGE OF WARM DRY AIR AT AROUND 850 MB AS NOTED ON 12Z GRB SNDG AND
LATEST RAPID RUC SNDGS AT KIMT HAS PRODUCED SEVERAL HUNDRED J/KG OF
CIN....KEEPING ATMOSPHERE CAPPED ENOUGH TO PROHIBIT SHOWERS FROM
FORMING OVER MUCH OF THE FCST AREA SO FAR THIS AFTERNOON. JUST IN
LATEST RADAR VOLUME SCAN STARTING TO SEE A FEW SHOWERS POPPING OVER
HOUGHTON COUNTY BUT WITH ONLY AROUND 200-300 J/KG OF MLCAPE NOT
REALLY EXPECTED MUCH IN WAY OF THUNDER.

AS MODELS SHOW FRONT MOVG SLOWLY EAST INTO CENTRAL FCST AREA...RAP
RUC SNDGS FOR KIMT SUGGESTS CAP ALOFT MAY ERODE JUST ENOUGH TO ALLOW
FOR SOME ISOLD TO SCT SHRA/TSRA TO FORM TOWARD SUNSET OVER CNTRL
FCST AREA. INCREASING 800-700 MB FGEN IN RESPONSE TO RIGHT ENTRANCE
REGION FORCING IN 140+ KT 3H JET OVER NRN PLAINS AND WRN ONTARIO
WILL BE MAIN DRIVING FORCE FOR BAND OF RAIN WHICH MODELS PROJECT TO
FORM LATE THIS EVENING AND EARLY OVERNIGHT OVER CENTRAL PORTION OF
THE FCST AREA. THIS BAND OF PCPN IS THEN PROGGED BY MODELS TO SHIFT
OVER THE WRN CWA LATE TONIGHT INTO WED AS BEST FGEN FORCING SHIFTS
WEST. LOWS TONIGHT WILL BE IN THE 40S UNDER MOSTLY CLOUDY SKIES.

MODEL AVG QPF INDICATES THAT PORTIONS OF GOGEBIC AND ONTONAGON
COUNTIES COULD SEE UP TO QUARTER INCH OF PCPN LATE TONIGHT INTO
WEDNESDAY. COLDER AIR (8H TEMPS DROPPING BLO 0C )SEEPING INTO THE
WRN CWA COULD CAUSE SOME SNOW TO MIX IN WITH RAIN BY LATE WED
AFTERNOON AS TEMPS FALL INTO THE MID TO UPPER 30S TOWARD EVENING.
N-NW ONSHORE FLOW OFF COOL LAKE SUPERIOR ALONG CLOUDY SKIES WILL
RESULT IN MAX TEMPS ON THE LOWER END OF MODEL GUIDANCE FOR WEDNESDAY
WITH HIGHS RANGING FROM THE LOWER TO MID 40S ALONG LAKE SUPERIOR TO
GENERALLY THE LOWER TO MID 50S EAST AND SCNTRL.

.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 432 PM EDT TUE APR 30 2013

FORECAST CONTINUES TO DEAL WITH THE UPPER TROUGH DEVELOPING IN THE
IN THE NORTHERN PLAINS AND WHAT HAPPENS TO IT AS IT CUTS OFF AROUND
THE END OF THIS WEEK AND DRIFTS THIS WEEKEND.

TO START THE PERIOD...THE FORECAST CONCERN IS THE STALLED 850MB
FRONT STRETCHING FROM NORTHERN LAKE SUPERIOR THROUGH SOUTHEAST
MINNESOTA AND INTO THE CENTRAL PLAINS AS THE UPPER TROUGH SLOWLY
SHIFTS EAST THROUGH THE NORTHERN PLAINS. THE POSITION OF THE FRONT
WILL BE THE MAIN CONCERN...AS THERE WILL LIKELY BE AN AXIS OF HIGHER
PRECIPITATION AMOUNTS ALONG THIS FRONT. LATEST TRENDS IN THE MODELS
IS THAT THE 850MB FRONT IS A LITTLE FARTHER WEST AND THE HEAVIEST
PRECIPITATION LOOKS TO FALL SOMEWHERE EAST OF DULUTH AND WEST OF A
LINE FROM BARAGA TO WATERSMEET. WITH THE AREA THE 850-700MB WAA/FGEN
IS LINING UP...WOULD THINK THAT THE BEST PRECIPITATION WOULD BE OVER
THE FAR WESTERN CWA...BUT STILL EXPECT LIGHTER VALUES OVER THE REST
OF THE WESTERN CWA. THIS MATCHES UP WELL WITH THE 09Z SREF QPF
PROBABILITIES. THERE WILL PROBABLY BE SOME SHOWERS OVER THE
CENTRAL U.P. BUT THE AMOUNTS SHOULD BE LIGHTER THAN SEEN OVER THE
WEST. UNFORTUNATELY...THIS PRECIPITATION WON/T HELP THE ALREADY
SWOLLEN RIVERS AND STREAMS OVER FAR WESTERN UPPER MICHIGAN AND WILL
HEIGHTEN THE AFFECTS IN THE HWO AND INDIVIDUAL RIVER PRODUCTS.

BASED OFF THE THERMAL FIELDS AND BUFKIT SOUNDINGS...IT APPEARS THAT
IT WILL MAINLY BE SNOW OVER THE FAR WESTERN CWA...WITH A RAIN/SNOW
MIX OVER THE WEST-CENTRAL...BEFORE CHANGING TO ALL RAIN EAST OF A
LINE FROM NEGAUNEE TO CRYSTAL FALLS. THERE STILL REMAINS SOME
UNCERTAINTY IN THE P-TYPE TYPE AS THEY HAVE BEEN VARYING IN HOW FAR
WEST THE WARM AIR ALOFT SLIDES. NAM AND OUR REGIONAL WRF-ARW DO HINT
AT A SOME DRYING ALOFT WHICH COULD LIMIT ICE CRYSTAL POTENTIAL OVER
THE WEST...WHICH WILL BE SOMETHING TO WATCH. IF THE PRECIP STAYS AS
SNOW OVER THE WEST HALF OF GOGEBIC AND WESTERN ONTONAGON
COUNTY...THEY COULD SEE SIGNIFICANT LATE SEASON
SNOWFALL...ESPECIALLY ON THE COLDER SURFACES AND HIGHER TERRAIN.
CURRENTLY HAVE BORDERLINE WARNING SNOW AMOUNTS FOR WEDNESDAY NIGHT
INTO THURSDAY MORNING...SO WILL CONTINUE TO MENTION IN THE HWO. IF
CONFIDENCE WAS A LITTLE GREATER ON EXACT LOCATION OF THE HEAVIEST
QPF...AND THERE WEREN/T SEVERAL OTHER FLOOD WARNING/WATCH/ADVISORY
PRODUCTS OUT FOR GOGEBIC COUNTY...COULD HAVE ISSUED A WINTER
STORM WATCH.

THE UPPER TROUGH STARTS THE CUTOFF PROCESS THURSDAY NIGHT INTO
FRIDAY MORNING...WHICH WILL ALLOW THE FLOW ALOFT TO BECOME MORE
SOUTHEASTERLY AND SHIFT THE FRONT WEST. THIS WILL PULL WARMER AIR
INTO THE AREA AND SHOULD LIMIT THE SNOW POTENTIAL. BUT THIS WARMER
AIR MOVING IN ALOFT WILL LEAD COLD AIR TRAPPED NEAR THE SURFACE.
THIS HAS BEEN HINTED AT OVER THE LAST DAY...BUT HAVE CONCERNS THAT
THE GROUND TEMPERATURES WON/T GO BELOW FREEZING. THUS...WILL JUST
HAVE A SLIGHT CHANCE MENTION FOR AREAS WITH RAIN AND TEMPS BELOW 31
DEGREES. WITH THE DIFFERENCES IN THE HANDLING OF THE TROUGH CUTTING
OFF...THERE ARE DIFFERENCES IN THE MOVEMENT OF THE FRONT...SO WILL
GO WITH A BROADER POPS HEADING INTO FRIDAY...BUT THE BEST FOCUS
OVER THE SOUTHWEST HALF.

THE WEEKEND INTO EARLY NEXT WEEK STILL REMAINS UP IN THE AIR DUE TO
THE DIFFERENCES IN THE LOCATION OF THE UPPER LOW. 00Z ECMWF IS
CONSISTENT WITH IT/S PREVIOUS RUN AND IS FARTHEST TO THE NORTH. 12Z
GFS CONTINUES IT/S TREND OF BEING WELL TO THE SOUTH OF THE AREA
/CENTRAL MISSISSIPPI VALLEY/...WHILE THE 12Z GEM HAS IT IN THE
GREAT LAKES. AS WITH YESTERDAY...WILL FOLLOW A GENERAL CONSENSUS
INTO NEXT WEEK AS THE LOCATION OF THE LOW HAS LARGE IMPLICATIONS ON
TEMPERATURES AND PRECIPITATION.
&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 220 PM EDT TUE APR 30 2013

A COLD FRONT WILL CROSS UPPER MICHIGAN THIS AFTERNOON BUT DRY AIR AT
LOW-LEVELS WILL LIKELY PROHIBIT SHOWERS FROM FORMING AT THE TAF
SITES. A DISTURBANCE MOVING ALONG THE FRONT LATE THIS EVENING AND
OVERNIGHT WILL BRING A BETTER CHC FOR SHRA ESPECIALLY AT THE WRN TAF
SITES. WINDS SHIFTING FROM SW TO MORE WESTERLY LATE TONIGHT INTO
WEDNESDAY WILL LIKELY BRING SOME LOWER CIGS ONSHORE AT KIWD AND KCMX
AS CONDITIONS LOWER FM VFR TO IFR OR PERHAPS LIFR. EXPECT GUSTY
SOUTH WINDS AOA 30 KTS AT KSAW THROUGH THIS AFTERNOON.
&&

.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 432 PM EDT TUE APR 30 2013

NO GALES SEEN IN THIS FORECAST PERIOD. WINDS WILL GET UP TO 30 KNOTS
ACROSS THE EASTERN PORTION OF LAKE SUPERIOR EARLY THIS EVENING WITH
TIGHTENING GRAD AHEAD OF COLD FRONT. WINDS THEN STAY GEENRALLY AT OR
BELOW 25 KNOTS FOR THE REST OF THE PERIOD.
&&

.HYDROLOGY...
ISSUED AT 432 PM EDT TUE APR 30 2013

ANOTHER DAY OF WARM TEMPERATURES HAS CONTINUED THE SNOW MELT AND
THE RISING RIVER LEVELS ACROSS THE AREA. FORTUNATELY...RAINFALL
AMOUNTS OVER THE LAST COUPLE OF DAYS HAVE BEEN FAIRLY LIGHT AND HAS
KEPT THE FLOODING CONCERNS TO THE SNOW MELT. THE MAIN SNOW LEFT
OVER THE AREA IS OVER THE HIGHER TERRAIN LOCATIONS OVER THE
WEST...WHERE VALUES ARE IN THE 3-15 INCH RANGE. THE WARM
TEMPERATURES TONIGHT SHOULD CONTINUE THE MELT...BUT IS SHOULD BE
SLOWED AS TEMPERATURES FALL BEHIND A COLD FRONT THAT MOVES
THROUGH TONIGHT. THIS FRONT WILL PRODUCE ISOLATED/SCATTERED SHOWERS
BUT WIDESPREAD MODERATE-HEAVY RAINFALL AMOUNTS ARE NOT EXPECTED.
ATTENTION THEN TURNS TO AN UPPER LEVEL FRONT THAT STALLS OVER FAR
WESTERN UPPER MICHIGAN WEDNESDAY THROUGH THURSDAY. THIS HAS THE
POTENTIAL TO PRODUCE OVER AN INCH OF QPF OVER THE WESTERN THIRD OF
UPPER MICHIGAN THROUGH THURSDAY NIGHT. THE HEAVIEST
AMOUNTS...POTENTIALLY EXCEEDING 1.5 INCHES WILL BE OVER WESTERN
ONTONAGON AND WESTERN GOGEBIC COUNTIES. WITH THE COLDER
TEMPERATURES...THERE IS UNCERTAINTY IN THE THE EXACT PRECIPITATION
TYPE...BUT IT LOOKS LIKE A RAIN/SNOW MIX OVER THE WEST AND MAINLY
SNOW OVER THE FAR WEST. THIS PRECIPITATION WILL NOT HELP MATTERS
OVER THE WESTERN CWA...WHERE MANY RIVERS/STREAMS/CREEKS ARE
EXCEEDING BANKFULL OR FLOODING. THIS PRECIPITATION WILL DEFINITELY
NEED TO BE WATCHED OVER THE NEXT DAY OR TWO TO PIN DOWN AMOUNTS AND
TYPES...WHICH WILL HELP DETERMINE THE TIME THEY WILL INFLUENCE THE
RIVERS. ELSEWHERE...THE TIME LAGGED FLOW INCREASES FROM THE SNOW
MELT WILL LEAD TO CONTINUED RISES OVER THE NORTH CENTRAL
TRIBUTARIES OF THE ESCANABA AND MICHIGAMME RIVERS. THESE AREAS MAY
SEE FLOODING OVER THE COMING DAYS.

IN THE NEAR TERM...THE GREATEST FLOODING THREAT IS FOR THE RIVERS
IN WEST AND CENTRAL UPPER MICHIGAN. SEVERAL RIVER FLOOD
WARNING/WATCH/ADVISORIES ARE ALREADY IN PLACE...ALONG WITH SOME
AERIAL FLOOD ADVISORIES. FOR COMPLETE DETAILS...SEE THE LATEST RIVER
FLOOD WATCHES...WARNINGS AND ADVISORIES.
&&

.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
  FLASH FLOOD WATCH UNTIL 10 PM CDT THIS EVENING FOR MIZ009.

LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&

$$

SHORT TERM...VOSS
LONG TERM...SRF
AVIATION...VOSS
MARINE...VOSS
HYDROLOGY...SRF







AREA FORECAST DISCUSSION

NWS MARQUETTE MI

 221 PM EDT TUE APR 30 2013

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 516 AM EDT TUE APR 30 2013

WV IMAGERY AND RUC ANALYSIS INDICATED A BROAD MID/UPPER LEVEL TROUGH
OVER THE NW CONUS RESULTING IN SW FLOW FROM THE CNTRL PLAINS TO THE
NRN GREAT LAKES. A VIGOROUS SHORTWAVE TROUGH WAS LCOATED OVER THE SE
CORNER OF SASK INTO FAR NW ND.  AT THE SFC...LOW PRES WAS LOCATED
OVER NE SOUTH DAKOTA WITH A WARM FRONT THROUGH SE MN INTO SRN WI. A
LLJ AHEAD OF THE WITH INFLOW OF MOIST/UNSTABLE AIR SUPPORTED TSRA
INTO SRN WI AND CNTRL LAKE MI. ISOLD SHOWERS NEAR ESC-ISQ HAD
DIMINISHED AS THE STRONGER CONVECTION DEVELOPED TO THE SOUTH.
UPSTREAM...A WEAK SHRTWV AHEAD OF THE LOW  SUPPORTED A BAND OF
SHRA/TSRA OVER NRN MN.

RADAR AND SATELLITE TRENDS SUGGEST THAT MOST OF THE CONVECTION OVER
WI WILL SLIDE JUST SOUTH OF THE CWA BUT MAY EXPAND JUST ENOUGH FOR
SOME SCT SHRA/TSRA...MAINLY SOUTH OF A LINE FROM IMT-ERY. AS THE SD
LOW LIFTS NORTHEAST THROUGH THROUGH NW MN TO NW ONTARIO...WAA AND
MOISTURE ADVECTION WILL INCREASE WITH THE STRENGTHENING SRLY FLOW.
TEMPS CLIMBING INTO THE LOWER TO MID 70S COMBINED WITH DEWPOINTS IN
THE LOWER TO MID 50S WILL RESULT IN MLCAPE VALUES IN THE 600-1200
J/KG RANGE BY THIS AFTERNOON. THE COLD FRONT DRAPED TO THE SOUTH OF
THE LOW MOVING INTO THE WEST UPPER MI THIS AFTERNOON WILL BE THE
MAIN FOCUS FOR SHRA/TSRA DEVELOPMENT. ALTHOUGH THE STRONGEST QVECTOR
CONV WILL BE WELL NORTH OF THE REGION...EVEN MODEST LOW LEVEL CONV
ALONG AND AHEAD OF THE FRONT SHOULD SUPPORT SCT TSRA THIS AFTERNOON
INTO THIS EVENING. SOME STRONGER STORMS MAY BE POSSIBLE WITH 0-6KM
SHEAR VALUES IN THE 40-50 KT...BUT THE GREATER SVR POTENTIAL IS
EXPECTED FARTHER SOUTH(PER SPC) WHERE INSTABILITY WILL BE GREATER.
THE HIGHEST POPS VALUES WERE INCLUDED OVER THE WEST LATE THIS
AFTERNOON AND INTO THE CNTRL AND EAST THIS EVENING...BEFORE
SHRA/TSRA WEAKEN WITH DIURNAL COOLING.

.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 442 AM EDT TUE APR 30 2013

NAM SHOWS A 500 MB RIDGE OVER THE EASTERN U.S. WITH A TROUGH IN THE
NORTHERN AND CENTRAL ROCKIES AND A CLOSED 500 MB LOW OVER THE GULF
COAST 12Z WED. THE TROUGH MOVES INTO THE NORTHERN PLAINS 00Z THU AND
INTO THE UPPER GREAT LAKES ON THU. NAM SHOWING SOME 850-500 MB
Q-VECTOR CONVERGENCE WITH DEEPER MOISTURE OVER THE WEST HALF OF
UPPER MICHIGAN 12Z WED WHICH REMAINS THROUGH 00Z THU. THIS NARROW
RIBBON OF DEEPER MOISTURE REMAINS OVER THE WESTERN CWA THROUGH 12Z
THU BEFORE THIS MOVES AND EXPANDS EASTWARD. GFS AND ECMWF SHOW ABOUT
THE SAME THING AS WELL.

THIS FORECAST PERIOD GETS DOMINATED BY COLDER AIR COMING INTO THE
AREA AND THERE COULD BE A RAIN/SNOW MIX ACROSS THE WESTERN U.P.
STARTING LATE WED NIGHT AND LASTING INTO THU NIGHT. THE WESTERN CWA
ALSO HAS THE BEST MOISTURE AND THEREFORE WILL HAVE THE HIGHEST POPS
WHILE THE EAST IS FURTHER AWAY FROM THE FRONTAL BAND PCPN THAT SETS
UP AND IS IN WARMER AIR AS WELL. QUITE A GRADIENT SETS UP IN
TEMPERATURES WITH THE COLDEST READINGS ACROSS THE WEST AND THE
WARMEST IN THE EAST FOR THROUGH THU. QPF WILL CONTINUE TO BE
HEAVIEST OVER THE WEST WITH ANYWHERE FROM 0.25 INCH ACROSS THE EAST
TO 1.25 IN THE WEST FROM WED TO THU NIGHT. THE COLD AIR DOES NOT
ARRIVE UNTIL LATE WED NIGHT ACROSS THE WEST AND COULD SEE ANYWHERE
FROM 1 TO 6 INCHES WEST OF A LINE FROM BIG BAY TO IRON RIVER FROM
WED NIGHT INTO THU NIGHT. DID RAISE TEMPERATURES A BIT FOR WED WITH
LATER ARRIVAL OF COLDER AIR AND RAISED THEM WED NIGHT AS WELL A
COUPLE DEGREES. OTHERWISE...DID NOT MAKE TOO MANY CHANGES TO THE
GOING FORECAST EXCEPT TO GO A BIT DRIER IN THE EASTERN CWA WHICH IS
FURTHER AWAY FROM THE FRONTAL BAND.

IN THE EXTENDED...GFS AND ECMWF SHOW A 500 MB TROUGH AND CLOSED LOW
OVER THE CENTRAL PLAINS 12Z FRI WITH A RIDGE OVER THE EASTERN U.S.
PATTERN DOES NOT CHANGE MUCH FOR 12Z SAT WITH THE 500 MB RIDGE
REMAINING STATIONARY. THIS 500 MB LOW CONTINUES TO SPIN ACROSS THE
CENTRAL PLAINS 12Z SUN FOR THE ECMWF AND THE GFS IS MUCH FURTHER
SOUTH WITH THE PLACEMENT OF THE 500 MB LOW. GFS CONTINUES TO MOVE
THE LOW EAST WELL SOUTH OF THE AREA 12Z MON WHILE THE ECMWF TAKES
THE LOW AND ASSOCIATED TROUGH THROUGH THE AREA. MANUAL PROGS KIND OF
WASH THIS SYSTEM OUT WITH TIME WITH WEAK SFC PRESSURE PATTERNS. WITH
SLOW CHANGE IN UPPER PATTERN...PERSISTENCE LOOKS TO BE THE WAY TO GO
FOR THIS FORECAST. TEMPERATURES WILL SLOWLY WARM THIS EXTENDED
FORECAST PERIOD FROM BELOW NORMAL TO NEAR NORMAL AND WILL BE WET
WITH PCPN CHANCES ALMOST EACH PERIOD.
&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 220 PM EDT TUE APR 30 2013

A COLD FRONT WILL CROSS UPPER MICHIGAN THIS AFTERNOON BUT DRY AIR AT
LOW-LEVELS WILL LIKELY PROHIBIT SHOWERS FROM FORMING AT THE TAF
SITES. A DISTURBANCE MOVING ALONG THE FRONT LATE THIS EVENING AND
OVERNIGHT WILL BRING A BETTER CHC FOR SHRA ESPECIALLY AT THE WRN TAF
SITES. WINDS SHIFTING FROM SW TO MORE WESTERLY LATE TONIGHT INTO
WEDNESDAY WILL LIKELY BRING SOME LOWER CIGS ONSHORE AT KIWD AND KCMX
AS CONDITIONS LOWER FM VFR TO IFR OR PERHAPS LIFR. EXPECT GUSTY
SOUTH WINDS AOA 30 KTS AT KSAW THROUGH THIS AFTERNOON.
&&

.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 442 AM EDT TUE APR 30 2013

NO GALES SEEN IN THIS FORECAST PERIOD. WINDS DO GET UP TO 30 KNOTS
ACROSS THE EAST AND NORTH CENTRAL TODAY AS A SFC LOW HEADS
NORTHEAST. WINDS THEN STAY BELOW 25 KNOTS FOR THE REST OF THE
PERIOD.
&&

.HYDROLOGY...
ISSUED AT 543 AM EDT TUE APR 30 2013

UNSEASONABLY WARM AIR AND HIGHER DEWPOINTS WILL CONTINUE TO FAVOR
RAPID MELTING OF THE REMAINING SNOWPACK ACROSS NORTH CENTRAL AND
WEST UPPER MICHIGAN KEEPING RIVER LEVELS HIGH. A COLD FRONT MOVING
THROUGH THIS AFTERNOON INTO TONIGHT MAY PRODUCE ADDITIONAL RAINFALL
OF A QUARTER TO HALF INCH IN SOME LOCATIONS. MUCH COOLER CONDITIONS
EXPECTED FOR REST OF WEEK COMBINED WITH LIMITED SNOWFALL SHOULD LEAD
TO A SLOW FALL IN RIVER LEVELS. ADDITIONAL CHANCES OF RAIN AND
EVEN SNOW OVER THE WEST ARE POSSIBLE WEDNESDAY AFTERNOON INTO
THURSDAY NIGHT...WITH THE HEAVIEST PRECIPITATION OVER THE WESTERN
THIRD OF UPPER MICHIGAN. SO...EVEN THOUGH TEMPERATURES WILL BE
COOLER THIS MAY BE OFFSET BY THE ADDITIONAL PRECIPITATION.

RIVERS OF PARTICULAR CONCERN DUE TO MELTING WILL BE THE BLACK RIVER
NEAR BESSEMER...THE TRAP ROCK RIVER...THE STURGEON RIVER OF
BARAGA/HOUGHTON COUNTIES...THE PESHEKEE RIVER...THE PAINT RIVER NEAR
CRYSTAL FALLS...THE ONTONAGON RIVER AT EWEN...THE CHOCOLAY RIVER
NEAR HARVEY...AND EVENTUALLY THE MICHIGAMME RIVER NEAR REPUBLIC AND
WITCH LAKE. MELTING SCENARIOS STILL LEAD TO SIGNIFICANT UNCERTAINTY WITH
THE RIVER FORECASTS FOR THE PESHEKEE AND MICHIGAMME BASINS WHERE
MOST OF THE MELTING HAS NOT HIT ANY OBSERVED RIVER POINTS. AT
OTHER LOCATIONS...SUFFICIENT RUNOFF FROM MELTING HAS BEEN OBSERVED
TO MORE ACCURATELY ASSESS THE MELT RATES FOR THE RIVER MODELS.

AN NWS SURVEY OF THE PESHEKEE RIVER MONDAY MORNING REVEALED THICK
ICE COVERING MOST OF THE RIVER NEAR AND DOWNSTREAM OF THE CHPM4
RIVER GAUGING LOCATION/AUTOMATED GAUGE DISCONTINUED BUT OBS ARE
BEING TAKEN USING A WIREWEIGHT GAUGE AT THE LOCATION/ AND THICK ICE
COVER ON MOST OF LAKE MICHIGAMME WHICH THE PESHEKEE DRAINS INTO. A
FEW ICE JAMS WERE NOTED MONDAY MORNING WHICH COULD CAUSE SOME
PROBLEMS OVER THE NEXT COUPLE OF DAYS AS THE RIVER RISES.

MAIN STEM RIVERS ARE NOT THE ONLY HAZARD...AS THERE IS ALSO A THREAT
OF AREAL FLOODING WITH SMALLER CREEKS/STREAMS AND STANDING WATER ON
ROADS. AREAL TYPE FLOODING HAS BEEN REPORTED...THE MOST WIDESPREAD
OVER GOGEBIC COUNTY WHERE AN AREAL FLOOD WARNING WAS ISSUED THROUGH
TUESDAY EVENING. FOR COMPLETE DETAILS...SEE THE LATEST RIVER FLOOD
WATCHES...WARNINGS AND ADVISORIES.
&&

.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
  FLASH FLOOD WATCH UNTIL 10 PM CDT THIS EVENING FOR MIZ009.

LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&

$$

SHORT TERM...JLB
LONG TERM...07
AVIATION...VOSS
MARINE...07
HYDROLOGY...JLB







AREA FORECAST DISCUSSION

NWS DETROIT/PONTIAC MI

 113 PM EDT TUE APR 30 2013


.AVIATION...

//DISCUSSION...

CONVECTION CONTINUES TO DIE OUT AS IT TRACKS THROUGH SOUTHEAST
MICHIGAN EARLY THIS AFTERNOON. CURRENT RADAR TRENDS SUPPORT
CONTINUING SHOWERS OVER THE TAF SITES FOR ANOTHER HOUR AS DRIER MORE
STABLE AIR MOVES IN FROM THE WEST...ENDING MUCH OF THE SHOWERS OVER
THE TAF SITES DURING THE LATE AFTERNOON. THIS WARM STABLE AIRMASS IS
EXPECTED TO REMAIN IN PLACE TONIGHT AND WEDNESDAY...WITH DRY WEATHER
EXPECTED FOR THE REST OF THE TAF PERIOD. ALTHOUGH WINDS ARE EXPECTED
TO BECOME LIGHT OVERNIGHT...WARM AIR ADVECTION AND LINGERING HIGH
CLOUDS ARE EXPECTED TO MITIGATE FOG DEVELOPMENT DURING THE OVERNIGHT
HOURS...HOWEVER A SHORT PERIOD OF MVFR FOG CANNOT BE RULED OUT
TOWARDS SUNRISE. THIS THREAT IS NOT HIGH ENOUGH TO INCLUDE IN THIS
SET OF TAFS.

FOR DTW...THE THREAT FOR THUNDERSTORMS IS BASICALLY OVER AT
DTW...HOWEVER ANOTHER HOUR OF SHOWERS IS POSSIBLE BEFORE THE RAIN
MOVES OFF TO THE EAST. ALTHOUGH THERE IS A POSSIBILITY OF MVFR FOG
EARLY WEDNESDAY MORNING...THE LACK OF SIGNIFICANT RAINS OVER THE
AIRPORT SHOULD KEEP THE THREAT FOR FOG DEVELOPMENT LOW AT THIS TIME.

//DTW THRESHOLD THREATS...

* MEDIUM CONFIDENCE IN CIGS ABOVE 5000 FEET THROUGH 19Z...HIGH
  CONFIDENCE IN CIGS ABOVE 5000 FEET AFTER 19Z.

&&

.PREV DISCUSSION...ISSUED 1029 AM EDT TUE APR 30 2013

UPDATE...

NWP MODELS CONTINUE TO HAVE ABSOLUTELY NO CLUE WITH REGARDS TO THE
ONGOING PRECIPITATION OVER THE WESTERN CWA. THESE MODELS ARE
COMPLETELY DRY...EVEN WITH THE 12Z CYCLE...WHICH AS RADAR AND
METAR REPORTS SHOW COULD NOT BE FURTHER FROM THE TRUTH. THE ONLY
MODEL THAT HAS ANY IDEA WHAT IS HAPPENING WITH THIS THETA-E DRIVEN
CONVECTION IS THE LOCAL HRRR MODEL WHICH PUSHES THESE RAIN SHOWERS
THROUGH THE CWA DURING THE EARLY AFTERNOON HOURS. THEREFORE WILL
RAISE POPS SIGNIFICANTLY INTO THE CATEGORICAL RANGE AS THIS
ACTIVITY SWEEPS THROUGH THE CWA THIS AFTERNOON.

WITH THIS ACTIVITY AND ABUNDANT CLOUD COVER HIGH TEMPERATURES WILL
SURELY NOT GET CLOSE TO 80 AS PREVIOUSLY ADVERTISED. WHILE THERE
IS STILL HOPE THE LATE APRIL SUN ANGLE WILL BE ABLE TO BOOST
TEMPERATURES BEHIND THESE SHOWERS...WILL TAKE A GOOD 5 TO 10 DEGREES
OFF PREVIOUS HIGH TEMPERATURES AS A FIRST SLICE AT HIGH
TEMPERATURES THIS AFTERNOON.

PREV DISCUSSION...ISSUED 359 AM EDT TUE APR 30 2013

SHORT TERM... TODAY AND TONIGHT

A WARM FRONT WILL MOVE FROM THE MIDWEST THROUGH LOWER MICHIGAN TODAY
AS LOW PRESSURE MOVES FROM THE NORTHERN PLAINS INTO NORTHERN
ONTARIO. THE FRONT WILL FIRST PRESENT CLOUDS, A CHANCE OF SHOWERS,
AND POSSIBLY A THUNDERSTORM DURING THE MORNING BEFORE PASSING NORTH
AND OPENING THE DOOR ON WARM TEMPERATURES DURING THE AFTERNOON
THROUGH TONIGHT.

EARLY MORNING SURFACE ANALYSIS INDICATES THE WARM FRONT IS SOMEWHAT
DIFFUSE BUT MODEL ANALYSIS FIELDS INDICATE A WELL DEFINED THETA-E
AXIS IN THE 850 TO 700 MB LAYER FEATURING 850 MB DEWPOINT AROUND 10C
THAT MATCHES UP WELL WITH UPSTREAM 00Z SOUNDINGS. THERE IS ALSO A
SHARP LEADING MOISTURE GRADIENT WHICH IS PROJECTED THROUGH LOWER
MICHIGAN DURING THE MORNING. THE ASSOCIATED SYSTEM RELATIVE
ISENTROPIC ASCENT AND MOISTURE ADVECTION IS EXPECTED TO BE A
DESTABILIZING PROCESS OVER OUR AREA THROUGH THE REST OF THE MORNING.
SPC MESOANALYSIS INDICATES MID LEVEL LAPSE RATES OF 7-8C/KM
AVAILABLE FROM UPSTREAM CENTERED OVER EASTERN IOWA WHICH WILL TEND
TO SPREAD OVER LOWER MICHIGAN BY ABOUT SUNRISE. IT IS THEN
REASONABLE TO EXPECT DEVELOPMENT OF CHANCE/SCATTERED COVERAGE OF
SHOWERS AND THUNDERSTORMS OVER THE ENTIRE AREA AS A STARTING POINT
WITH AN UPDATE TO GREATER COVERAGE AS RADAR TRENDS DICTATE
REFINEMENT ON LOCATION.

THE PASSAGE OF THE WARM FRONT BY EARLY AFTERNOON WILL THEN BRING THE
WARM SECTOR OF THE LARGER SCALE PATTERN OVER OUR AREA. MODEL
SOUNDINGS INDICATE THE MIXED LAYER WILL REMAIN RELATIVELY SHALLOW,
ONLY UP TO ABOUT 875 MB, IN SUPPORT OF MAX TEMPS IN THE MID TO UPPER
70S MOST LOCATIONS. MODEL SURFACE STREAMLINES ORIGINATE MORE FROM
THE OHIO VALLEY THROUGH THE DAY SO AN INTERIOR MAX OF 80 WILL BE AT
THE TOP OF THE RANGE. MORE IMPORTANT IS THE SLIGHT ONSHORE WIND
COMPONENT THAT WILL KEEP READINGS COOLER NEAR THE LAKE HURON
SHORELINE AND LAKE ST CLAIR/ERIE AGGREGATE. THIS SAME TENDENCY IN
THE WIND WILL THEN BACK EVEN MORE TOWARD THE SOUTHEAST WITH SOME
DECOUPLING TONIGHT. THIS WILL ALLOW MIN TEMPS TO SETTLE DOWN INTO
THE 50S WITH DRY CONDITIONS AND PARTLY CLOUD SKY THROUGH SUNRISE
WEDNESDAY.

LONG TERM...WEDNESDAY THROUGH MONDAY.

WEDNESDAY...A DIGGING TROUGH INTO COLORADO AND ANTICYCLONICALLY
CURVED JET STREAK EJECTING NORTHWARD THROUGH CANADA WILL FORCE
AGGRESSIVE DOWNSTREAM AMPLIFICATION OF THE EASTERN NOAM UPPER LEVEL
RIDGE. 500MB VORTICITY FIELD IS SUGGESTIVE THAT DEEP COLUMN
SUBSIDENCE WILL BE IN PLACE OVER THE CENTRAL GREAT LAKES...WITH A
SHARP EASTERN GRADIENT TO THE PRECIPITATION OVER PORTIONS OF
WISCONSIN/IOWA. CLOSED HEIGHT CONTOURS AT 500MB ARE SHOWN TO SNEAK
INTO SOUTHEASTERN MICHIGAN WEDNESDAY AFTERNOON. THE GOOD CONNECTION
OF REMNANT ELEVATED MIXED LAYER WILL STILL EXIST FOR WEDNESDAY
AFTERNOON...SUPPORTING THE WARMEST TEMPERATURES OF THIS STRETCH. LOW
80 APPEARS A GOOD FORECAST FOR THE TRI CITIES WITH MID TO UPPER 70S
ELSEWHERE.

THE ANTICYCLONIC INFLECTION/BUBBLE IN JET IS EXPECTED TO WORK
THROUGH THE REGION LATE WEDNESDAY NIGHT AND THURSDAY. THIS FEATURE
SHOULD SUPPORT AN ADDITIONAL SHORTWAVE RIDGE COMPONENT. NCEP MODELS
ARE VERY SUSPECT WITH QPF SNEAKING ONTO THE WESTERN FRINGES OF THE
CWA...PRIMARILY IN THE LEE OF LAKE MICHIGAN. PRECIPITATION SHOULD
REMAIN IN THE COLD SECTOR...BUT BREAKS OUT CONVECTION IN A SECONDARY
ZONE WELL AHEAD OF MAIN STATIONARY BAROCLINIC ZONE. THE PROBLEM IS
THIS DOESN/T HAVE THE LOOK OF A WEATHER SYSTEM THAT WOULD FORCE
PREFRONTAL TROUGH CONVECTION. THE BELIEF IS THERE ARE LIKELY SURFACE
MOISTURE PARAMETRIZATION ISSUES WHICH IS SOME CAUSE TO THE NOISY
SOLUTIONS. THE FORECAST IS ALREADY SIDING IN A DRY FASHION...AND DID
NOT SEE ANYTHING IN THE NEW NWP TO SUGGEST OTHERWISE.
UNFORTUNATELY...THIS IS A BINARY ALL OR NOTHING TYPE FORECAST WITH A
CONSIDERABLE AMOUNT OF BUST POTENTIAL IF PRECIPITATION MOVES IN. THE
AIRMASS IN PLACE WILL HAVE UNDERGONE SOME HOMOGENIZATION BY
THURSDAY. THEREFORE...HIGHS ARE GENERALLY 3 TO 4 DEGREES COOLER THAN
THE PRECEDING DAY.

MODELS THEN DIVERGE CONSIDERABLY FOR THIS WEEKEND. THE FAVORED ECMWF
SHOWS A CONSIDERABLE CUTOFF EVENT OVER THE CENTRAL PART OF THE
COUNTRY BY FRIDAY. THE UPSTREAM RESPONSE IS TO FORM A POSITIVE
HEIGHT ANOMALY COUPLET TO THE NORTHEAST OF THE CLOSED LOW. THE ECMWF
SUGGESTS THE CENTER OF THE ANOMALY WILL MEANDER...BUT SHOULD
MAINTAIN A FIRM GRASP OF LOWER MICHIGAN THROUGH SATURDAY. THE
FORECAST IS SIDED THERE...AND WILL GO DRY THROUGH THE FIRST HALF OF
THE WEEKEND. DO NOT FEEL PARTICULARLY GOOD ABOUT THE MAX T FORECAST
THIS WEEKEND AS THERE IS PLENTY OF COLD/PRECIPITATION/CLIMO BIASED
SOLUTIONS FACTORING IN THE OFFERED GUIDANCE. WILL GIVE IT SOME TIME
BEFORE GETTING MORE AGGRESSIVE WITH THE WEEKEND TEMPERATURES.

MARINE...

LOW PRESSURE MOVING FROM NORTHERN MINNESOTA INTO NORTHERN ONTARIO
TODAY WILL BOOST SOUTHERLY WIND OVER THE OPEN WATERS OF LAKE HURON,
BUT WARM AIR MOVING OVER THE COLD WATER WILL PROVIDE VERY HIGH
STABILITY. THIS WILL KEEP WAVE ACTION SUBDUED THROUGH TONIGHT. AFTER
THAT, THE TRAILING COLD FRONT WILL SETTLE CLOSE ENOUGH TO THE
STRAITS FOR LIGHTER WIND OVER ALL MARINE AREAS. FAVORABLE MARINE
CONDITIONS ARE THEN ANTICIPATED THROUGH THE REST OF THE WEEK AS THE
FRONT IS PROJECTED TO STALL OVER THE WESTERN GREAT LAKES.

&&

.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MI WATERS OF LAKE ERIE...NONE.

&&

$$

AVIATION.....KURIMSKI
UPDATE.......KURIMSKI
SHORT TERM...BT
LONG TERM....CB
MARINE.......BT


YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).







AREA FORECAST DISCUSSION

NWS HASTINGS NE

 114 PM CDT TUE APR 30 2013

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 545 AM CDT TUE APR 30 2013

CLEARLY THE MAIN CONCERN DURING THE NEXT 24 HOURS IS THE RISK FOR
POTENTIALLY SEVERAL STRONG TO SEVERE STORMS MAINLY BETWEEN 7 PM
AND 3 AM TONIGHT...AND MAINLY WITHIN THE SOUTHEAST 1/2 OF THE CWA.
OTHERWISE...TODAY MARKS THE TRANSITION DAY BETWEEN THE 80+ DEGREE
WARMTH OF THE PAST FEW DAYS...AND THE UNWELCOME RETURN TO A WINTRY
FEEL TOMORROW.

09Z OBJECTIVE SURFACE ANALYSIS IS HIGHLIGHTED BY THE MUCH-
ADVERTISED COLD FRONT...THAT PER AUTOMATED OBS AND RADAR IMAGERY
IS ALREADY WELL THROUGH AT LEAST THE NORTHWEST 1/3 OF THE
CWA...AND CONTINUES STEADILY PASSING SOUTHEAST. BEHIND THE FRONT
ARE NORTH-NORTHWEST WINDS WITH SUSTAINED SPEEDS GENERALLY 10-20
MPH WITH HIGHER GUSTS. THIS FRONT IS CONNECTED ACROSS THE REGION
BY TWO PRIMARY SURFACE LOW CENTERS...A 991 MILLIBAR NEAR THE
SD/ND/MN BORDER...AND A 996MB ONE ALONG THE KS/CO BORDER. AHEAD OF
THE FRONT...STEADY SOUTH-SOUTHWEST BREEZES 10-20 MPH HAVE BEEN THE
NORM THROUGH THE NIGHT...PROMOTING VERY MILD READINGS MAINLY IN
THE 60S. ALTHOUGH TEMPS ARE FALLING OFF SOMEWHAT BEHIND THE
BOUNDARY...A GOOD CHUNK OF THE CWA SHOULD MAKE IT THROUGH 8AM
WITHOUT DROPPING BELOW THE 55-60 RANGE. ALOFT...WATER VAPOR
IMAGERY AND SHORT TERM MODEL DATA HIGHLIGHT A LARGE SCALE TROUGH
AND ASSOCIATED UPPER JET STREAK CENTERED OVER THE NORTHERN
PLAINS/ROCKIES...WITH SEVERAL EMBEDDED SHORTWAVE TROUGHS...THE
MOST VIGOROUS OF WHICH IS SWINGING ALONG THE SD/CANADA BORDER.

FOR THE 7AM-7PM DAYTIME PERIOD...THE VAST MAJORITY...IF NOT THE
ENTIRE CWA SHOULD REMAIN THUNDERSTORM/RAIN FREE...AND ONLY HAVE A
SLIGHT CHANCE OF STORMS AFTER 5 PM IN FAR SOUTHEAST ZONES MAINLY
SOUTHEAST OF A HEBRON-PLAINVILLE LINE. ALOFT...BROAD WEST-
SOUTHWEST FLOW WILL PERSIST OVER THE CENTRAL PLAINS...AS THE
VIGOROUS VORT MAX OVER SD SWINGS NORTHEAST INTO CANADA...WHILE
ADDITIONAL PIECES OF ENERGY SLIDE SOUTHEAST OUT OF THE NORTHWEST
CONUS TOWARD THE CENTRAL ROCKIES...HELPING TO SLOWLY DEEPEN THE
DEVELOPING POSITIVELY TILTED LARGE SCALE TROUGH. AT THE
SURFACE...THE COLD FRONT WILL CONTINUE MAKING STEADY PROGRESS
SOUTHWARD ACROSS THE CWA TODAY...ALTHOUGH IT WILL SLOW AND
ESSENTIALLY STALL OUT AS IT REACHES FAR SOUTHEAST COUNTIES...AS IT
IS COUNTER-ACTED BY A STRENGTHENING WARM FRONT/INVERTED TROUGH
AXIS EXTENDING NORTHEAST FROM A DEEPENING SURFACE LOW NEAR THE
CO/OK/KS/TX BORDER AREA. FOR THE MAJORITY OF THE CWA THAT GETS
BEHIND THE COLD FRONT TODAY...BREEZES WILL AVERAGE AT LEAST 15-20
MPH WITH HIGHER GUSTS...AS THE WIND DIRECTION GRADUALLY SHIFTS
FROM NORTHERLY TO NORTHEASTERLY. TEMPERATURE-WISE...DESPITE
PASSING HIGH CLOUDS...ITS NOW LOOKING LIKE THERE WILL BE ENOUGH
SUNSHINE...AND ALSO WEAK ENOUGH COLD AIR ADVECTION TO ALLOW TEMPS
TO CLIMB HIGHER THAN PREVIOUSLY FORECAST...AND BASED ON A BLEND OF
VARIOUS MODELS/GUIDANCE HAVE RAISED HIGHS ROUGHLY 5 DEGREES ALL
AREAS...NOW AIMING FOR MID 60S NORTHWEST...NEAR 70 CENTRAL...AND
LOW 80S FAR SOUTHEAST. IF THE RAP MODEL IS ONTO SOMETHING...IT MAY
BE EVEN WARMER YET...BUT HAVE LARGELY DISCOUNTED IT FOR NOW. AS
FOR PRE-7PM STORM CHANCES...THEY ARE LOOKING FAIRLY SLIM DESPITE
THE LATEST NAM BUILDING 1000+ J/KG OF 0-1MLCAPE IN FAR SOUTHEAST
ZONES LATE THIS AFTERNOON. FORECAST SOUNDINGS SHOW A PRETTY
FORMIDABLE CAP TO SURFACE-BASED CONVECTION OWING TO WARM 700MB
TEMPS IN AN ELEVATED MIXED LAYER. PER REFLECTIVITY FORECAST FROM
THE 00Z 4KM WRF-NMM AND ALSO THE 09Z RAP...THAYER AND MITCHELL
COUNTIES WOULD BEAR THE MOST WATCHING FOR POSSIBLE STORM
DEVELOPMENT...WHICH COULD BECOME SEVERE QUICKLY SHOULD IT FORM.
ALTHOUGH A BRIEF NEAR-SURFACE BASED SUPERCELL CANNOT BE RULED
OUT...IT WOULD LIKELY TAKE ON A SOMEWHAT LINEAR TENDENCY PRETTY
QUICKLY WITH FLOW ALOFT PARALLEL TO THE LOW LEVEL FRONTAL ZONE.

TURNING TO THE 7PM-7AM TONIGHT PERIOD...CONFIDENCE IS CONSIDERABLY
HIGHER IN WIDESPREAD SHOWER/THUNDERSTORM DEVELOPMENT...ESPECIALLY
AFTER SUNSET...AND POPS HAVE BEEN BUMPED UP INTO THE 80-90 PERCENT
RANGE FOR MUCH OF THE NIGHT. ALOFT...SHORTWAVE ENERGY WILL
TRANSLATE INTO THE PLAINS FROM THE WEST AS THE PARENT LONGWAVE
TROUGH SETS UP ALONG AN AXIS FROM ND TO THE CENTRAL ROCKIES BY
SUNRISE WEDNESDAY MORNING. WITHIN THE ENTRANCE REGION OF A DAKOTAS
UPPER JET STREAK...LOW-MID LEVEL SOUTHERLY WINDS SPEEDS/RESULTANT
MOISTURE CONVERGENCE WILL RAMP UP MARKEDLY AROUND/AFTER
SUNSET INTO THE FRONTAL ZONE...WITH MOISTURE TRANSPORT SURGING
INTO THE CWA EVIDENT AT BOTH 850 AND 700MB. VARIOUS MODEL
QPF/REFLECTIVITY PROGS SUCH AS FROM THE NAM AND 4KM WRF-NMM AGREE
ON THE SCENARIO OF A RAPID INCREASE IN THUNDERSTORM DEVELOPMENT
THIS EVENING ACROSS MOST IF NOT ALL OF THE CWA...BUT ESPECIALLY
THE SOUTHEAST 1/2. THIS SHOULD BE A FAIRLY CLASSIC SETUP FOR AT
LEAST MARGINALLY SEVERE HAIL AROUND QUARTER SIZE OR SLIGHTLY
LARGER...WITH A CONSENSUS OF THE LATEST NAM/GFS SUGGESTING AT
LEAST 500-1500 J/KG OF MUCAPE IN THE 850-700MB LAYER THROUGH
06Z...IN THE PRESENCE OF DEEP LAYER 0-6KM SHEAR OF GENERALLY 40-60
KT. THIS COULD YIELD AT LEAST A HANDFUL OF ELEVATED SUPERCELL
STRUCTURES TRAINING WITHIN THE SAME GENERAL CORRIDOR...NOT ALL
THAT UNLIKE THE EVENT IN EARLY APRIL THAT AFFECTED MUCH OF THE NEB
CWA. ALTHOUGH A STRONG STORM IS POSSIBLE ALMOST ANYWHERE...THE
GREATEST THREAT FOR LARGE HAIL AND POSSIBLY SEVERE WIND GUSTS
SHOULD RESIDE GENERALLY SOUTH OF AN ELWOOD-OSCEOLA LINE INCLUDING
KS COUNTIES. GRADUALLY DECREASING INSTABILITY SHOULD RESULT IN A
DECREASING SEVERE THREAT BY AROUND 3 AM OR SO...BUT NOT
NECESSARILY SO. SOME PLACES COULD ALSO PICK UP HEALTHY RAINFALL
AMOUNTS OF 1-2+ INCHES...BUT NOT FORESEEING MUCH OF AN ORGANIZED
FLOODING THREAT GIVEN THE RECENT WARM...DRY STRETCH. ALL OF THIS
WILL BE TAKING PLACE IN THE PRESENCE OF STEADY LOW LEVEL COLD AIR
ADVECTION...MARKED BY NORTH-NORTHEAST WINDS OF AT LEAST 20 MPH AND
POSSIBLY CLOSER TO SUSTAINED 30 MPH AT TIMES EVEN OUTSIDE STORM
ACTIVITY. BY SUNRISE WEDNESDAY MORNING...HAVE LOW TEMPS AIMED FROM
THE MID 30S IN NORTHWEST COUNTIES...TO LOW-MID 40S SOUTHEAST. ITS
NOT COMPLETELY OUT OF THE QUESTION THAT SOME SNOW COULD START
MIXING IN WITH RAIN BETWEEN 09Z-12Z...IN FAR NORTHWEST ZONES...BUT
WOULD EXPECT LITTLE IF ANY ACCUMULATION BEFORE SUNRISE...AND EVEN
THEN ONLY IN THE VALLEY/WESTERN DAWSON COUNTY AREA.

.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 545 AM CDT TUE APR 30 2013

BIGGEST CHALLENGE WILL BE DETERMINING TIMING OF CHANGEOVER TO SNOW
WEDNESDAY AND DETERMINING SNOW AMOUNTS THROUGH WEDNESDAY NIGHT.

WE KICK OFF WEDNESDAY WITH A HIGHLY AMPLIFIED UPPER LEVEL TROUGH
OVER THE INTERMOUNTAIN WEST THAT WILL CONTINUE TO AMPLIFY AND HEAD
TOWARD THE CENTRAL PLAINS. PLENTY OF COLD AIR ADVECTION WILL BE
UNDERWAY...BUT ELEVATED CONVECTION COULD STILL BE OCCURRING DURING
THE EARLY MORNING ON WEDNESDAY IN OUR SOUTHEAST. PROBABLY NOT ENOUGH
INSTABILITY FOR SEVERE WEATHER ANYMORE. ALSO...TEMPERATURES WILL NOT
GO ANYWHERE ON WEDNESDAY WITH THE STRONG COLD AIR ADVECTION...SO
TEMPERATURES WILL BE STEADY OR FALLING DURING THE DAY WITH MIX OF
SNOW/SNOW WORKING IN TO THE SOUTHEAST DURING THE DAY. WIND WILL BE
QUITE PERSISTENT FROM THE NORTH...ESPECIALLY TO THE SOUTH WITH STRONG
HEIGHT RISES. WE COULD BE PUSHING WIND ADVISORY OVER NORTH CENTRAL
KANSAS.

LOOKS A LITTLE TRICKY FOR TIMING OF SWITCHING OVER TO SNOW...AND
TOWARD A MIDDLE OF THE ROAD APPROACH AMONG MODEL
SOLUTIONS...CONSIDERING TIMING AND QPF AMOUNTS. WE COULD PICK UP ONE
TO THREE INCHES...BUT MOST OF THIS WOULD BE ON GRASSY
SURFACES...CONSIDERING THAT THIS WILL BE IN THE MONTH OF MAY.
ALSO...THE NAM INDICATES A POSSIBLE LOSS OF SATURATION IN THE DENDRITIC
GROWTH ZONE LATE AFTERNOON AND EVENING WEDNESDAY...WHICH COULD GIVE
US SOME DRIZZLE/FREEZING DRIZZLE FOR A SHORT PERIOD. ALSO...SLEET
MIGHT NOT BE OUT OF THE QUESTION ACCORDING TO SOME MODEL
SUGGESTIONS...BUT I WILL LEAVE BOTH OUT FOR NOW...AS IT DOES NOT
LOOK THAT LIKELY FOR MUCH SLEET WITH SUCH STRONG COLD AIR ADVECTION
AND THE LACK OF SATURATION IN THE DENDRITIC GROWTH ZONE IS VERY
DICEY.

WE COULD STILL HAVE SOME LEFTOVER SNOW IN THE SOUTH/EAST ON THURSDAY
MORNING AS THE TROUGH AXIS WILL NOT PASS TO THE EAST OF THE CWA
UNTIL AT LEAST AFTERNOON.

MODELS THEN CLOSE OFF A LOW WITHIN THE TROUGH BY THURSDAY NIGHT AND
TO BE HONEST...IT IS A FREE FOR ALL FRIDAY THROUGH THE REST OF THE
LONG TERM FORECAST AS THERE IS ABSOLUTELY NO AGREEMENT AMONG MODELS
OF WHAT HAPPENS WITH THE UPPER LOW. ENSEMBLES ARE OUT OF PHASE AS
WELL. STAYING WITH CONTINUITY HERE...BUT CONFIDENCE IS NOT HIGH WITH
THE LATEST FORECASTS FROM MODELS. WE CAN ONLY HOPE FOR SOME SORT OF
AGREEMENT DEVELOPING IN THE NEAR FUTURE. THERE IS GREAT POTENTIAL
FOR BIG BUSTS FOR TEMPERATURE FORECASTS...ESPECIALLY HIGH
TEMPERATURES...AND WE COULD VERY WELL END UP MUCH COOLER THAN
CURRENTLY ADVERTISED.

&&

.AVIATION...(FOR THE 18Z KGRI TAF THROUGH 18Z WEDNESDAY
AFTERNOON) ISSUED AT 1230 PM CDT TUE APR 30 2013

DETERIORATING CONDITIONS ARE EXPECTED AT KGRI THROUGH THE NEXT 24
HOURS AS CEILINGS LOWER AND VISIBILITIES ARE REDUCED DUE TO
DEVELOPMENT OF SHOWERS AND THUNDERSTORMS NEAR A COLD FRONTAL
BOUNDARY THAT IS DRAPED ACROSS THE FORECAST AREA.
INITIALLY...EXPECT SOME THUNDERSTORMS TO DEVELOP IN THE VICINITY
OF KGRI...LIKELY AFTER 01/03Z...AS A SECONDARY FRONTAL BOUNDARY
APPROACHES THE TERMINAL. MODEL CONSENSUS IS FAIRLY GOOD WITH MORE
WIDESPREAD THUNDERSTORM ACTIVITY AFTER 01/06Z...WITH SUFFICIENT
INSTABILITY LINGERING FOR ADDITIONAL SHOWER AND THUNDERSTORM
DEVELOPMENT THROUGH ABOUT 01/12Z. BEHIND THE SECONDARY COLD
FRONT...EXPECT LIGHT RAIN...POSSIBLY MIXED WITH SNOW LATER IN THE
DAY...TO DEVELOP AFT 01/12Z...WITH SOME AREAS OF REDUCED
VISIBILITIES POSSIBLE ALONG WITH VERY GUSTY NORTHERLY WINDS BEHIND
THE FRONT. AT THIS TIME...EXPECT GUSTS TO REACH 35KTS...OR
POTENTIALLY HIGHER BEHIND THE FRONT WEDNESDAY AFTERNOON...AS
STRONG PRESSURE RISES ARE REALIZED.

&&

.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&

$$

SHORT TERM...PFANNKUCH
LONG TERM...HEINLEIN
AVIATION...SAR







AREA FORECAST DISCUSSION

NWS BUFFALO NY

 209 PM EDT TUE APR 30 2013

.SYNOPSIS...
A WEAK UPPER LEVEL DISTURBANCE WILL GENERATE A FEW ISOLATED SHOWERS
AND CLOUDINESS THIS AFTERNOON. OTHERWISE...HIGH PRESSURE
ANCHORED OFF THE NEW ENGLAND COAST WILL REMAIN IN PLACE FOR THE REST
OF THE WEEK AND PROVIDE US WITH MORE SUNSHINE AND WELL ABOVE AVERAGE
TEMPERATURES.

&&

.NEAR TERM /THROUGH TONIGHT/...
HIGH PRESSURE REMAINS CENTERED OFF THE NEW ENGLAND COAST WITH SURFACE
RIDGING EXTENDED WEST ACROSS NEW YORK STATE.  WELL TO THE WEST LOW
PRESSURE IS CENTERED OVER WESTERN ONTARIO CANADA WITH A COLD FRONT
EXTENDED SOUTH INTO THE CENTRAL PLAINS. A THUNDERSTORM COMPLEX TO
OUR WEST HAS SIGNIFICANTLY WEAKENED ACROSS MICHIGAN WITH INFRARED
SATELLITE IMAGERY SHOWING WARMING CLOUD TOPS. SHORT TERM MODEL
GUIDANCE INCLUDING THE 15Z HRRR AND 09Z SREF SHOW THIS COMPLEX
CONTINUING TO WEAKEN THROUGH THE AFTERNOON AS IT MOVES TOWARD A
BUILDING UPPER LEVEL RIDGE AND ASSOCIATED DOWNWARD MOTION OVER THE
EASTERN STATES. WE ARE NOT EXPECTING ANY IMPACT FROM THIS SYSTEM TO
OUR FORECAST AREA TODAY. THROUGH THE AFTERNOON EXPECT JUST AN
ISOLATED SHOWER EAST OF LAKE ONTARIO WHERE AN UPPER LEVEL SHORT WAVE
MAY STILL FORCE THIS. A GRADUAL WEST TO EAST DECREASE IN CLOUDS
ACROSS OUR AREA. THE INCREASE IN SUNSHINE FROM YESTERDAY WILL HELP
TO BOOST TODAYS TEMPS INTO THE LOWER 70S ALONG THE LAKE PLAINS.
OTHERWISE...EXPECT TEMPERATURES TO RANGE THROUGH THE 60S.

TONIGHT...THE SURFACE RIDGE WILL REMAIN IN PLACE WHILE THE LOW TO
OUR WEST LIFTS NORTH TO JAMES BAY. THE UPPER LEVEL RIDGE MUCH OF THE
EAST COAST IS FORECAST TO BUILD FURTHER WEST ACROSS THE OHIO VALLEY
AND LOWER GREAT LAKES. INCREASING LARGE SCALE SUBSIDENCE ASSOCIATED
WITH THE EXPANDING RIDGE WILL HELP THE CLOUDS TO THIN OUT EVEN
MORE...ALTHOUGH THE MODELS ARE HINTING THAT SOME MID AND HIGH LEVELS
CLOUDS FROM UPSTREAM THUNDERSTORM COMPLEX MAY SPILL ACROSS OUR AREA
DURING THE NIGHT. BEST CHANCE FOR THIS WOULD BE ACROSS LAKE ONTARIO
AND THE EASTERN LAKE ONTARIO REGION. WILL MONITOR THIS SYSTEM
THROUGH THE DAY. MAY HAVE TO INCLUDE A SMALL CHANCE FOR A SHOWER OR
THUNDERSTORM ACROSS LAKE ONTARIO AND TO THE EAST IF SYSTEM HOLDS
TOGETHER A LITTLE BETTER THAN MODELS SHOW. THE MILD SOUTHERLY FLOW
WILL ALSO KEEP AREA TEMPERATURES ABOVE SEASONAL AVERAGES.

&&

.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
THE PATTERN ACROSS NORTH AMERICA WILL CONTINUE TO AMPLIFY ON
WEDNESDAY AS A TROUGH DIGS THROUGH THE ROCKIES AND NORTHERN HIGH
PLAINS...FORCING STRONG DOWNSTREAM HEIGHT RISES ACROSS THE EASTERN
HALF OF THE NATION. INCREASING SUBSIDENCE AND DRYING BENEATH A
BUILDING UPPER LEVEL RIDGE WILL CONTINUE TO ERODE THE LOW/MID LEVEL
MOISTURE THAT WAS LEFT BEHIND BY THE WEAK TROUGH OF THE PAST FEW
DAYS. THIS WILL BRING INCREASING AMOUNTS OF SUNSHINE FOR WEDNESDAY.

850MB TEMPS RISE TO +9C TO +10C BY AFTERNOON...WHICH WILL SUPPORT
HIGHS IN THE MID TO UPPER 70S AT LOWER ELEVATIONS. THE SOUTH TO
SOUTHEAST SYNOPTIC SCALE WIND SHOULD BE STRONG ENOUGH TO PRECLUDE
LAKE BREEZE FORMATION IN MOST AREAS...WITH A FEW POSSIBLE EXCEPTIONS
NOTED IN MESOSCALE MODEL GUIDANCE. IT APPEARS A LOCAL LAKE BREEZE
MAY DEVELOP ALONG THE SOUTH SHORE OF LAKE ONTARIO MAINLY ACROSS THE
NIAGARA AND ORLEANS COUNTY SHORE WITH COOLER TEMPS THERE. GRADIENT
ONSHORE FLOW WILL ALSO KEEP AREAS FROM STONY POINT TO CAPE VINCENT
IN JEFFERSON COUNTY COOLER.

WEDNESDAY NIGHT HIGH PRESSURE REMAINS PARKED ALONG THE NEW ENGLAND
COAST WITH LIGHT SOUTHERLY RETURN FLOW ACROSS THE LOWER LAKES. THIS
WILL KEEP TEMPS UP INTO THE LOWER 50S ON THE LAKE PLAINS OF WESTERN
NY WITH 40S ELSEWHERE.

ON THURSDAY THE MID/UPPER LEVEL RIDGE REMAINS PARKED DIRECTLY
OVERHEAD PROVIDING ANOTHER DRY DAY WITH A GOOD AMOUNT OF SUNSHINE.
850MB TEMPS AROUND +10C WILL AGAIN SUPPORT MID TO UPPER 70S IN MANY
AREAS. SURFACE HIGH PRESSURE WILL BUILD MORE DIRECTLY OVERHEAD ON
THURSDAY...WHICH MEANS SYNOPTIC SCALE FLOW WILL LIKELY BE TOO LIGHT
TO PREVENT LAKE BREEZE FORMATION. THUS...EXPECT ALL THE LAKESHORES
OF BOTH LAKES TO BE COOLER ON THURSDAY.

HIGH PRESSURE SURFACE AND ALOFT REMAINS IN PLACE THURSDAY NIGHT. A
WEAK BAND OF MID LEVEL MOISTURE PEELING OFF A CUTOFF LOW OFF THE NEW
ENGLAND COAST MAY BRING A LITTLE MORE CLOUD COVER TO CENTRAL NY
OVERNIGHT.

&&

.LONG TERM /FRIDAY THROUGH MONDAY/...
AN EXCEPTIONAL PERIOD OF DRY AND WARM WEATHER WILL CONTINUE THROUGH
NEXT WEEKEND AS A PAIR OF CUTOFF LOWS DEVELOP OVER THE CENTRAL CONUS
AND WESTERN ATLANTIC...ALLOWING A NEARLY STATIONARY OMEGA BLOCK TO
DEVELOP OVER THE OHIO VALLEY AND EASTERN GREAT LAKES. THIS WILL
CONTINUE TO PROVIDE DRY WEATHER THROUGH THE WEEKEND WITH NOTHING
MORE THAN A FEW PERIODS OF HIGH CLOUD AS WEAK DISTURBANCES CROSS THE
TOP OF THE RIDGE. 850MB TEMPS WILL RUN IN THE +8C TO +10C RANGE
DAILY WHICH WILL SUPPORT HIGHS WELL INTO THE 70S. MOS GUIDANCE
CONTINUES TO LOOK TOO LOW FOR THIS PERIOD...AS IS TYPICALLY THE CASE
HERE DURING PRE-FOLIAGE WARM SPELLS. WITH HIGH PRESSURE NEARLY
OVERHEAD...SYNOPTIC SCALE WINDS WILL BE LIGHT ENOUGH TO ALLOW LOCAL
LAKE BREEZES TO DEVELOP ON MOST DAYS WITH COOLER TEMPS ALONG THE
LAKESHORES.

BY MONDAY THE CLOSED LOW OVER THE MIDWEST WILL BEGIN TO MAKE A
LITTLE PROGRESS EAST...BUT THE CONSENSUS FROM THE NEW 00Z GFS AND
ECMWF RUNS IS TO KEEP IT FAR ENOUGH WEST FOR ANOTHER DRY DAY ON
MONDAY WITH CONTINUED WARMTH.

&&

.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
VFR CIGS WILL CONTINUE TO DRIFT EAST ACROSS THE REGION AS A MID
LEVEL SHORT WAVE WORKS ACROSS NEW YORK. JUST A FEW ISOLATED RAIN
SHOWERS SHOWING UP ON RADAR. A THUNDERSTORM COMPLEX TO OUR WEST IS
WEAKENING OVER MICHIGAN WITH NO IMPACT EXPECTED AT THE TAF SITES
TODAY. ACROSS THE SOUTHERN TIER KJHW SHOULD IMPROVE FROM MVFR CIGS
TO VFR THIS AFTERNOON.

HIGH PRESSURE  OFF THE EAST COAST WILL RESULT IN MAINLY VFR
CONDITIONS ACROSS THE REGION TONIGHT EXCEPT FOR KJHW WHERE SOME MVFR
CIGS MAY REDEVELOP IN THE VALLEYS OF THE SOUTHERN TIER. THERE IS A SMALL
CHANCE THAT SOME LINGERING SHOWER/THUNDERSHOWER ACTIVITY FROM THE
COMPLEX TO OUR WEST MAY HOLD TOGETHER ACROSS LAKE ONTARIO AND MAY
APPROACH KART THIS EVENING BUT LEFT OUR OF THE TAFS AT THIS POINT.
NAM BUFKIT SHOWS A WEAK 30 KNOT 1KFT LLJ WILL MOVE OVER THE AREA
OVERNIGHT WHICH WILL HELP KEEP WINDS FROM SLACKENING MUCH OVERNIGHT.
HIGH PRESSURE WILL CONTINUE VFR WEDNESDAY..

OUTLOOK...
WEDNESDAY NIGHT THROUGH SUNDAY...VFR.

&&

.MARINE...
A THUNDERSTORM COMPLEX TO OUR WEST OVER MICHIGAN WILL LIFT NORTH
WITH ITS SOUTHERN PORTION FALLING APART BEFORE REACHING EASTERN LAKE
ERIE. SOME LINGERING SHOWERS CLOSER TO THE CENTER OF THIS SYSTEM MAY
BRUSH THE NORTHERN HALF OF LAKE ONTARIO LATER THIS EVENING.
OTHERWISE...HIGH PRESSURE ANCHORED OFF THE NEW ENGLAND COAST WILL
REMAIN NEARLY STATIONARY THROUGH THE WEEK. THIS WILL KEEP THE LOWER
LAKES IN A A PERSISTENT LIGHT TO MODEST SOUTHEASTERLY FLOW THAT WILL
RESULT IN MINIMAL WAVES ALONG THE NEARSHORES OF BOTH LAKES.

&&

.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...NONE.

&&

$$

SYNOPSIS...JM/SMITH
NEAR TERM...SMITH
SHORT TERM...HITCHCOCK
LONG TERM...HITCHCOCK
AVIATION...SMITH
MARINE...SMITH








AREA FORECAST DISCUSSION

NWS CLEVELAND OH

 123 PM EDT TUE APR 30 2013

.SYNOPSIS...
HIGH PRESSURE WILL STAY JUST EAST OF THE AREA THROUGH SUNDAY. A LOW
WILL MOVE NORTH INTO ILLINOIS THURSDAY INTO FRIDAY THEN DRIFT WEST
INTO MISSOURI ON THE WEEKEND.

&&

.NEAR TERM /THROUGH TONIGHT/...
SHOWERS AND THUNDERSTORMS MOVING ACROSS SOUTHEAST MICHIGAN ARE
SHOWING A DIMINISHING TREND AS CLOUD TOPS WARM. STILL EXPECTING THIS
TO PASS NORTH OF TOLEDO BUT DID INCLUDE A 20 PERCENT CHANCE OF A
SHOWER/THUNDERSTORM IN THE LATEST UPDATE. CLOUDS WILL BE OVERCAST
IN EXTREME NW OH AS A THICK MID CLOUD DECK HAS OVERSPREAD THE AREA
BEFORE CLEARING LATE IN THE DAY. ESLEWHERE...A HEALTHY CU DECK HAS
DEVELOPED ACROSS MUCH OF THE AREA WITH PARTLY TO MOSTLY CLOUDY
SKIES. ALTHOUGH THESE WILL START TO SCATTER OUT LATER THIS
AFTERNOON...THIS HAS SLOWED WARMING AND TWEAKED TEMPERATURES DOWN
BY A COUPLE DEGREES MOST AREAS...AND SEVERAL DEGREES IN NW PA.

PREVIOUS DISCUSSION...HIGH PRESSURE AT UPPER LEVEL WILL START TO
BUILD OVER THE AREA TODAY. THIS WILL PROVIDE GENERAL SUBSIDENCE
AND WORK TO SUPPRESS CONVECTION THAT TRIES TO DEVELOP. WILL HAVE
TO WATCH FOR THE POSSIBILITY OF A STRAY SPRINKLE OVER MI DROPPING
ESE TOWARD LAKE ERIE THIS MORNING BEFORE THE RIDGING STARTS TO
BUILD. HEALTHY CONVECTION HAS DEVELOPED IN SW MI LAST HOUR OR TWO
AND LATEST HRRR BRINGS SOME LEFTOVER SHRA FROM THIS ACTIVITY INTO
THE NW THREE COUNTIES AROUND 15Z. HAVE INCREASED POP FOR THE NW
THRU EARLY AFTERNOON TO ALLOW FOR A CHANCE OF SHRA.

A PREDOMINATELY SOUTH FLOW AND THE COMPRESSIONAL WARMING WILL
PUSH HIGHS THIS AFTERNOON WELL INTO THE 70S. HOWEVER...THE
PRESSURE GRADIENT MAY BE WEAK ENOUGH FOR A LAKE BREEZE TO DEVELOP
CLOSE TO THE LAKESHORE SO WILL KEEP TEMPS A LITTLE COOLER ALONG
THE IMMEDIATE LAKE SHORE.

&&

.SHORT TERM /WEDNESDAY THROUGH FRIDAY NIGHT/...
UPPER RIDGING OVER THE AREA SHOULD KEEP CONDITIONS DRY FOR MOST OF
THE AREA TONIGHT THROUGH FRI NIGHT. THE ONLY EXCEPTIONS WILL BE FOR
A POSSIBLE STAY SHRA WED AS GOOD MOISTURE AROUND 850 MB GETS PUSHED
BACK NW OVER THE CWA. WILL CONTINUE TO KEEP POPS BELOW 15% SO NO
PRECIP WILL BE MENTIONED IN FORECAST. THE INVERTED LOW PUSHING NORTH
INTO THE IL/IN AREA THU INTO THU NIGHT COULD PRODUCE SOME ISOLATED
SHRA THAT MAY GET CLOSE TO OUR WESTERN BORDER THU THRU FRI BUT THE
RISK STILL LOOKS LOW ENOUGH TO KEEP POPS BELOW 15%.

THE INVERTED LOW WILL CAUSE WINDS TO BACK TOWARD THE EAST THU INTO
FRI SO WOULD EXPECT HIGH TEMPS TO LOOSE A FEW DEGREES AFTER PEAKING
ON WED. ALSO THE EAST DIRECTION WILL HAVE A MUCH BETTER CHANCE OF
BACKING TO NE FOR THE AFTERNOON NEAR THE LAKE SO TEMPS EVEN COOLER
THERE.

&&

.LONG TERM /SATURDAY THROUGH MONDAY/...
LONG TERM BEGINS ON SATURDAY WITH THE MODELS SHOWING THE CUTOFF
UPPER LOW OVER THE CENTRAL PLAINS.  THE ECMWF REMAINS CONSISTENT
FROM 00Z TO 12Z RUNS WITH THE LOW NEAR KANSAS CITY WHILE THE 00Z GFS
HAS SHIFTED THE LOW SOUTH TO ARKANSAS. BY SUNDAY THE ECMWF TAKES THE
LOW TO IOWA WHILE THE GFS MOVES IT TO MISSOURI.  MONDAY THE MODELS
DIVERGE FURTHER WITH THE ECMWF TAKING THE LOW ACROSS THE CENTRAL
GREAT LAKES INTO ONTARIO WHILE THE GFS HAS THE LOW IN SERN MISSOURI
AND SRN IL. WILL CONTINUE WITH PERSISTENCE KEEPING SLIGHT CHANCE
POPS WEST AT FIRST THEN INCREASING TO CHANCE SUNDAY BEFORE SPREADING
CHANCE POPS EAST SUNDAY NIGHT AND MONDAY.  TEMPS SEASONAL.

&&

.AVIATION /17Z TUESDAY THROUGH SATURDAY/...
AS CUMULUS FIELD BUILDS ACROSS THE FORECAST AREA EXPECT AREAS TO
GO IN AND OUT OF MVFR AS CIGS BECOME OCCASIONALLY BROKEN. LOW CLOUDS
WILL BEGIN TO DISSIPATE AFTER SUNSET WITH THE EXCEPTION OF MID TO
HIGH CLOUDS THAT WILL SHEAR DOWNSTREAM OF A DISTURBANCE MOVING
ACROSS LAKE MICHIGAN. A RAIN SHOWER CANNOT BE RULED OUT AT TOLEDO
BETWEEN 18-22Z AS THE TROUGH PIVOTS TO THE NORTHWEST AND PULLS OUT
INTO ONTARIO DURING THE OVERNIGHT. THERE WILL BE SUFFICIENT LOW
LEVEL MOISTURE AT TOL FDY MFD AND YNG TO INITIATE EARLY MORNING MVFR
FOG. ADEQUATE MIXING AND DRIER AIR ALOFT WILL SCOUR OUT ANY FOG
BY MID MORNING.

.OUTLOOK...VFR EXCEPT FOR LOCAL LIGHT FOG/MIST EACH MORNING.

&&

.MARINE...
EXPECTING A FAIRLY STAGNANT WEATHER PATTERN TO DEVELOP ACROSS THE
REGION WITH HIGH PRESSURE TO OUR EAST AND LOW PRESSURE ACROSS THE
NATIONS MID SECTION.  THIS WILL KEEP WINDS FROM THE SOUTH TO
SOUTHEAST ON THE LAKE THROUGH THE NEAR AND INTERMEDIATE TERM.  NO
HEADLINES EXPECTED THROUGH THE PERIOD.

&&

.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...NONE.

&&

$$
SYNOPSIS...ADAMS
NEAR TERM...ADAMS/KEC
SHORT TERM...ADAMS
LONG TERM...TK
AVIATION...MAYERS
MARINE...TK







AREA FORECAST DISCUSSION

NWS CLEVELAND OH

 1248 PM EDT TUE APR 30 2013

.SYNOPSIS...
HIGH PRESSURE WILL STAY JUST EAST OF THE AREA THROUGH SUNDAY. A LOW
WILL MOVE NORTH INTO ILLINOIS THURSDAY INTO FRIDAY THEN DRIFT WEST
INTO MISSOURI ON THE WEEKEND.

&&

.NEAR TERM /THROUGH TONIGHT/...

SHOWERS AND THUNDERSTORMS MOVING ACROSS SOUTHEAST MICHIGAN ARE
SHOWING A DIMINISHING TREND AS CLOUD TOPS WARM. STILL EXPECTING THIS
TO PASS NORTH OF TOLEDO BUT DID INCLUDE A 20 PERCENT CHANCE OF A
SHOWER/THUNDERSTORM IN THE LATEST UPDATE. CLOUDS WILL BE OVERCAST
IN EXTREME NW OH AS A THICK MID CLOUD DECK HAS OVERSPREAD THE AREA
BEFORE CLEARING LATE IN THE DAY. ESLEWHERE...A HEALTHY CU DECK HAS
DEVELOPED ACROSS MUCH OF THE AREA WITH PARTLY TO MOSTLY CLOUDY
SKIES. ALTHOUGH THESE WILL START TO SCATTER OUT LATER THIS
AFTERNOON...THIS HAS SLOWED WARMING AND TWEAKED TEMPERATURES DOWN
BY A COUPLE DEGREES MOST AREAS...AND SEVERAL DEGREES IN NW PA.

PREVIOUS DISCUSSION...HIGH PRESSURE AT UPPER LEVEL WILL START TO
BUILD OVER THE AREA TODAY. THIS WILL PROVIDE GENERAL SUBSIDENCE
AND WORK TO SUPPRESS CONVECTION THAT TRIES TO DEVELOP. WILL HAVE
TO WATCH FOR THE POSSIBILITY OF A STRAY SPRINKLE OVER MI DROPPING
ESE TOWARD LAKE ERIE THIS MORNING BEFORE THE RIDGING STARTS TO
BUILD. HEALTHY CONVECTION HAS DEVELOPED IN SW MI LAST HOUR OR TWO
AND LATEST HRRR BRINGS SOME LEFTOVER SHRA FROM THIS ACTIVITY INTO
THE NW THREE COUNTIES AROUND 15Z. HAVE INCREASED POP FOR THE NW
THRU EARLY AFTERNOON TO ALLOW FOR A CHANCE OF SHRA.

A PREDOMINATELY SOUTH FLOW AND THE COMPRESSIONAL WARMING WILL
PUSH HIGHS THIS AFTERNOON WELL INTO THE 70S. HOWEVER...THE
PRESSURE GRADIENT MAY BE WEAK ENOUGH FOR A LAKE BREEZE TO DEVELOP
CLOSE TO THE LAKESHORE SO WILL KEEP TEMPS A LITTLE COOLER ALONG
THE IMMEDIATE LAKE SHORE.

&&

.SHORT TERM /WEDNESDAY THROUGH FRIDAY NIGHT/...
UPPER RIDGING OVER THE AREA SHOULD KEEP CONDITIONS DRY FOR MOST OF
THE AREA TONIGHT THROUGH FRI NIGHT. THE ONLY EXCEPTIONS WILL BE FOR
A POSSIBLE STAY SHRA WED AS GOOD MOISTURE AROUND 850 MB GETS PUSHED
BACK NW OVER THE CWA. WILL CONTINUE TO KEEP POPS BELOW 15% SO NO
PRECIP WILL BE MENTIONED IN FORECAST. THE INVERTED LOW PUSHING NORTH
INTO THE IL/IN AREA THU INTO THU NIGHT COULD PRODUCE SOME ISOLATED
SHRA THAT MAY GET CLOSE TO OUR WESTERN BORDER THU THRU FRI BUT THE
RISK STILL LOOKS LOW ENOUGH TO KEEP POPS BELOW 15%.

THE INVERTED LOW WILL CAUSE WINDS TO BACK TOWARD THE EAST THU INTO
FRI SO WOULD EXPECT HIGH TEMPS TO LOOSE A FEW DEGREES AFTER PEAKING
ON WED. ALSO THE EAST DIRECTION WILL HAVE A MUCH BETTER CHANCE OF
BACKING TO NE FOR THE AFTERNOON NEAR THE LAKE SO TEMPS EVEN COOLER
THERE.

&&

.LONG TERM /SATURDAY THROUGH MONDAY/...
LONG TERM BEGINS ON SATURDAY WITH THE MODELS SHOWING THE CUTOFF
UPPER LOW OVER THE CENTRAL PLAINS.  THE ECMWF REMAINS CONSISTENT
FROM 00Z TO 12Z RUNS WITH THE LOW NEAR KANSAS CITY WHILE THE 00Z GFS
HAS SHIFTED THE LOW SOUTH TO ARKANSAS. BY SUNDAY THE ECMWF TAKES THE
LOW TO IOWA WHILE THE GFS MOVES IT TO MISSOURI.  MONDAY THE MODELS
DIVERGE FURTHER WITH THE ECMWF TAKING THE LOW ACROSS THE CENTRAL
GREAT LAKES INTO ONTARIO WHILE THE GFS HAS THE LOW IN SERN MISSOURI
AND SRN IL. WILL CONTINUE WITH PERSISTENCE KEEPING SLIGHT CHANCE
POPS WEST AT FIRST THEN INCREASING TO CHANCE SUNDAY BEFORE SPREADING
CHANCE POPS EAST SUNDAY NIGHT AND MONDAY.  TEMPS SEASONAL.

&&

.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
CONDITIONS MVFR/IFR IN EARLY MORNING FOG WITH LOWEST CONDITIONS
EAST AWAY FROM THE LAKE. MORNING FOG WILL LIFT QUICKLY WITH
CONDITIONS BECOMING VFR BY 14Z. AFTER DAYBREAK VFR CONDITIONS
WILL PERSIST THROUGH THE DAY AND INTO THE EVENING. EXPECTING THE
DEVELOPMENT OF SOME FOG AGAIN TONIGHT.

.OUTLOOK...VFR EXCEPT FOR LOCAL LIGHT FOG/MIST EACH MORNING.

&&

.MARINE...
EXPECTING A FAIRLY STAGNANT WEATHER PATTERN TO DEVELOP ACROSS THE
REGION WITH HIGH PRESSURE TO OUR EAST AND LOW PRESSURE ACROSS THE
NATIONS MID SECTION.  THIS WILL KEEP WINDS FROM THE SOUTH TO
SOUTHEAST ON THE LAKE THROUGH THE NEAR AND INTERMEDIATE TERM.  NO
HEADLINES EXPECTED THROUGH THE PERIOD.

&&

.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...NONE.

&&

$$
SYNOPSIS...ADAMS
NEAR TERM...ADAMS/KEC
SHORT TERM...ADAMS
LONG TERM...TK
AVIATION...TK
MARINE...TK







AREA FORECAST DISCUSSION

NWS STATE COLLEGE PA

 514 PM EDT TUE APR 30 2013

.SYNOPSIS...
A WEAK AREA OF LOW PRESSURE NEAR THE OUTER BANKS OF NORTH
CAROLINA WILL MAINTAIN A SOUTHEASTERLY FLOW OF MOIST AIR INTO
CENTRAL PENNSYLVANIA TONIGHT...KEEPING CLOUDS AROUND WITH A
MENTION OF DRIZZLE FOR THE SOUTHERN MOUNTAINS. A HIGH AMPLITUDE
BLOCKING RIDGE WILL SET UP ACROSS THE REGION FOR THE SECOND HALF
OF THE WEEK...BRINGING DRY AND MILD WEATHER WHICH IS EXPECTED TO
LAST INTO THE UPCOMING WEEKEND.

&&

.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
THE MAIN BELT OF ANOMALOUS EASTERLIES SHIFTS GRADUALLY SOUTH TO
THE CAROLINAS TONIGHT INTO WEDNESDAY...WHILE AN ANOMALOUS /+2-3
SIGMA/ 500 MB RIDGE AMPLIFIES FROM THE TENNESSEE VALLEY TO EASTERN
CANADA. IN ADDITION...DRIER AIR IS ALREADY BEGINNING TO ADVECT IN
FROM THE EAST...WHICH WILL AID IN RAISING CIGS AND GRADUALLY
DIMINISHING CLOUDS OVERNIGHT FROM THE EAST. STUBBORN STRATOCU
SHOULD LINGER THE LONGEST /THROUGH 12Z/ IN THE SW WHERE SPOTTY
DRIZZLE WILL REMAIN POSS OVERNIGHT /AS PER THE 4KM NAM AND HRRR -
THOUGH THEY HAVE BEEN OVERDOING POTENTIAL FOR LIGHT PRECIP OVER
THE PAST 24 HRS/.

LOW TEMPS WILL BE IN THE 40S...WITH COOLEST READINGS IN THE
NORTHEAST AND EAST WHERE CLOUDS WILL THIN FIRST AND DEWPOINTS
WILL LOWER FIRST.

&&

.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH WEDNESDAY NIGHT/...
ANOMALOUS /+2-3 SIGMA/ 500 MB RIDGE BEGINS TO QUICKLY AMPLIFY
FROM THE TENNESSEE VALLEY TO EASTERN CANADA ON WED. AFTER A CLOUDY
START IN THE SW...SKIES SHOULD BECOME PARTLY CLOUDY EVERYWHERE BY
LATE MORNING WITH SUNSHINE CONTINUING TO INCREASE IN THE
AFTERNOON AS SUBSIDENCE DEEPENS UNDER THE BUILDING HIGH.

HIGH TEMPS WEDNESDAY WILL WARM BY 8-10F COMPARED TO
TUESDAY...WHICH WILL BE NEAR NORMAL ACROSS THE SUSQ VALLEY...AND
5-8F DEGREES ABOVE NORMAL OVER THE NRN AND WESTERN MTNS. LOWS WED
NIGHT WILL BE CHILLY WITH STRENGTHENING HIGH PRESSURE BRINGING
LIGHT WINDS AND DRIER AIR. READINGS WILL BOTTOM OUT IN THE
40S...WITH SOME UPPER 30S POSS IN NORTHEASTERN MTNS.

&&

.LONG TERM /THURSDAY THROUGH TUESDAY/...
THE 30/12Z GLOBAL NUMERICAL GUIDANCE CONTINUES TO ADVERTISE A HIGHLY
AMPLIFIED MERIDIONAL FLOW PATTERN AT 500MB THROUGH THE MEDIUM RANGE
PERIOD...WITH AN ANOMALOUS RIDGE/TROUGH/RIDGE CONFIGURATION EXPECTED
FROM JUST OFFSHORE THE PAC NW TO THE CENTRAL US AND INTERIOR NORTHEAST
STATES.

A MID-ATLANTIC FORECAST PERSPECTIVE SHOWS A SHARP 580DM RIDGE
CENTERED BETWEEN THE AFOREMENTIONED CENTRAL CONUS H5 TROUGH/CLOSED
LOW AND COMPACT H5 ENERGY PROGGED TO DROP SWD FROM THE MARITIMES
ALONG/JUST OFFSHORE THE NEW ENGLAND COAST ON DAY 3-4 /THUR-FRI/.
THIS FEATURE WILL RETREAT INTO THE NRN ATLC BY THE WEEKEND...WITH
THE FOCUS SHIFTING TO THE EVOLUTION OF THE CLOSED LOW OVER THE
CENTRAL STATES.

THE ECMWF LIES ON THE WWD SIDE OF THE DETERMINISTIC ENVELOPE SHOWING
A MORE COASTAL TRACK WITH THE ENERGY DROPPING OFFSHORE THE NE COAST
EARLY IN THE PERIOD. HOWEVER THE OVERALL MODEL SPREAD IS PRETTY LOW
WITH THIS FEATURE...WHICH SHOULD SEND A BACKDOOR COLD FRONT INTO THE
REGION ON FRIDAY AND ACCENTUATE A WEST-EAST TEMPERATURE GRADIENT.

THE DOMINANT SYNOPTIC FEATURE DRIVING THE SENSIBLE WEATHER IN
CENTRAL PA THROUGH THE BALANCE OF THE PERIOD WILL BE THE HIGH
AMPLITUDE UPPER-LEVEL RIDGE...WHICH SHOULD EFFECTIVELY BLOCK PCPN
ASSOCD WITH THE CENTRAL US CLOSED LOW FROM REACHING THE
NORTHEAST/MID-ATLC STATES AT LEAST THROUGH THE UPCOMING WEEKEND.

THE OPERATIONAL MODELS AND THEIR ENSEMBLE MEANS HAVE MANY VARIED
SOLUTIONS CONCERNING THE EVENTUAL EWD PROGRESSION OF THE CENTRAL US
CLOSED LOW. IN GENERAL...THERE APPEARS TO BE A SLIGHTLY SLOWER AND
SOUTHWARD TREND IN THE MOST RECENT NON-NCEP MODEL DATA. THE SLOWER
TREND MAKES SENSE GIVEN THAT THE MODELS USUALLY TRY TO BREAK DOWN
THESE PATTERNS TOO QUICKLY. THE LATE-SPRING/EARLY MAY TIMEFRAME IS
ALSO A CLIMATALOGICALLY FAVORED PERIOD FOR BLOCKY PATTERNS/CUT-OFF
LOWS. WITH REGARD TO THE EWD MVMT OF THE CLOSED LOW AND CORRESPONDING
CHCS FOR PCPN...WILL UTILIZE AN EVEN BLEND OF AVAILABLE GUIDANCE. THIS
IDEA SEEMS TO FIT THE WPC PREFERENCE OF AN INTERMEDIATE 12Z CANADIAN
OR EC/GEFS MEAN SOLUTION.

&&

.AVIATION /21Z TUESDAY THROUGH SUNDAY/...

LARGE ANTICYCLONE TO OUR NORTH AND EAST KEEPS US IN THE EASTERLY
FLOW. THE FLOW SHOWS SOME SIGNS OF WEAKENING AND THE SATELLITE
IMAGERY SHOWS THE SHRINKING LOW CLOUD REGION STUCK OVER CENTRAL
PENNSYLVANIA. 4KM MODELS AND RADAR IMPLY SOME LINGERING DZ/-RA IN
SW MOUNTAINS AND MOST LOCATIONS WILL BE IN THE MVFR/VFR RANGE.
SOME BREAKS IN CLOUDS NEAR KLNS-KMDT NOW COMING IN FROM THE EAST
AND KBFD IS ABOUT 50 MILES TOO FAR EAST OF THE VFR REGION.

THINGS SHOULD IMPROVE WEDNESDAY AS THE FLOW WEAKENS AS STATED IN
PREVIOUS DISCUSSION...THE MAIN BELT OF ANOMALOUS EASTERLY WINDS SHIFTS
GRADUALLY SOUTH TO THE CAROLINAS TONIGHT INTO WEDNESDAY...WHILE AN
ANOMALOUS /+2-3 SIGMA/ 500 MB RIDGE AMPLIFIES FROM THE TENNESSEE
VALLEY TO EASTERN CANADA. IN ADDITION...DRIER AIR IS ALREADY
BEGINNING TO ADVECT IN FROM THE EAST...WHICH WILL AID IN RAISING
CIGS AND GRADUALLY DIMINISHING CLOUDS FROM THE EAST THIS AFTERNOON
INTO THE OVERNIGHT. STUBBORN LOWER STRATOCU SHOULD LINGER THE
LONGEST /THROUGH 12Z/ IN THE SW WHERE SPOTTY DRIZZLE WILL REMAIN
POSS OVERNIGHT /AS PER THE 4KM NAM AND HRRR - THOUGH THEY HAVE
BEEN OVERDOING POTENTIAL FOR LIGHT PRECIP OVER THE PAST 24 HRS/.

LINGERING LOW CIGS WILL GIVE WAY TO VFR CONDITIONS AREAWIDE ON WED
AS HIGH PRESSURE RIDGE STRENGTHENS OVER THE REGION. THIS WILL
BEGIN AN EXTENDED PERIOD OF EXCELLENT FLYING CONDITIONS.


.OUTLOOK...

WED...LOW CIGS POSS EARLY OVR THE W MTNS...OTHERWISE VFR.

THU-SUN...VFR. NO SIG WX EXPECTED.

&&

.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.

&&

$$
SYNOPSIS...RXR
NEAR TERM...RXR
SHORT TERM...RXR
LONG TERM...STEINBUGL
AVIATION...GRUMM/RXR







AREA FORECAST DISCUSSION

NWS STATE COLLEGE PA

 321 PM EDT TUE APR 30 2013

.SYNOPSIS...
A WEAK AREA OF LOW PRESSURE NEAR THE OUTER BANKS OF NORTH
CAROLINA WILL MAINTAIN A SOUTHEASTERLY FLOW OF MOIST AIR INTO
CENTRAL PENNSYLVANIA TONIGHT...KEEPING CLOUDS AROUND WITH A
MENTION OF DRIZZLE FOR THE SOUTHERN MOUNTAINS. A HIGH AMPLITUDE
BLOCKING RIDGE WILL SET UP ACROSS THE REGION FOR THE SECOND HALF
OF THE WEEK...BRINGING DRY AND MILD WEATHER WHICH IS EXPECTED TO
LAST INTO THE UPCOMING WEEKEND.

&&

.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
THE MAIN BELT OF ANOMALOUS EASTERLIES SHIFTS GRADUALLY SOUTH TO
THE CAROLINAS TONIGHT INTO WEDNESDAY...WHILE AN ANOMALOUS /+2-3
SIGMA/ 500 MB RIDGE AMPLIFIES FROM THE TENNESSEE VALLEY TO EASTERN
CANADA. IN ADDITION...DRIER AIR IS ALREADY BEGINNING TO ADVECT IN
FROM THE EAST...WHICH WILL AID IN RAISING CIGS AND GRADUALLY
DIMINISHING CLOUDS OVERNIGHT FROM THE EAST. STUBBORN STRATOCU
SHOULD LINGER THE LONGEST /THROUGH 12Z/ IN THE SW WHERE SPOTTY
DRIZZLE WILL REMAIN POSS OVERNIGHT /AS PER THE 4KM NAM AND HRRR -
THOUGH THEY HAVE BEEN OVERDOING POTENTIAL FOR LIGHT PRECIP OVER
THE PAST 24 HRS/.

LOW TEMPS WILL BE IN THE 40S...WITH COOLEST READINGS IN THE
NORTHEAST AND EAST WHERE CLOUDS WILL THIN FIRST AND DEWPOINTS
WILL LOWER FIRST.

&&

.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH WEDNESDAY NIGHT/...
ANOMALOUS /+2-3 SIGMA/ 500 MB RIDGE BEGINS TO QUICKLY AMPLIFY
FROM THE TENNESSEE VALLEY TO EASTERN CANADA ON WED. AFTER A CLOUDY
START IN THE SW...SKIES SHOULD BECOME PARTLY CLOUDY EVERYWHERE BY
LATE MORNING WITH SUNSHINE CONTINUING TO INCREASE IN THE
AFTERNOON AS SUBSIDENCE DEEPENS UNDER THE BUILDING HIGH.

HIGH TEMPS WEDNESDAY WILL WARM BY 8-10F COMPARED TO
TUESDAY...WHICH WILL BE NEAR NORMAL ACROSS THE SUSQ VALLEY...AND
5-8F DEGREES ABOVE NORMAL OVER THE NRN AND WESTERN MTNS. LOWS WED
NIGHT WILL BE CHILLY WITH STRENGTHENING HIGH PRESSURE BRINGING
LIGHT WINDS AND DRIER AIR. READINGS WILL BOTTOM OUT IN THE
40S...WITH SOME UPPER 30S POSS IN NORTHEASTERN MTNS.

&&

.LONG TERM /THURSDAY THROUGH TUESDAY/...
THE 30/12Z GLOBAL NUMERICAL GUIDANCE CONTINUES TO ADVERTISE A HIGHLY
AMPLIFIED MERIDIONAL FLOW PATTERN AT 500MB THROUGH THE MEDIUM RANGE
PERIOD...WITH AN ANOMALOUS RIDGE/TROUGH/RIDGE CONFIGURATION EXPECTED
FROM JUST OFFSHORE THE PAC NW TO THE CENTRAL US AND INTERIOR NORTHEAST
STATES.

A MID-ATLANTIC FORECAST PERSPECTIVE SHOWS A SHARP 580DM RIDGE
CENTERED BETWEEN THE AFOREMENTIONED CENTRAL CONUS H5 TROUGH/CLOSED
LOW AND COMPACT H5 ENERGY PROGGED TO DROP SWD FROM THE MARITIMES
ALONG/JUST OFFSHORE THE NEW ENGLAND COAST ON DAY 3-4 /THUR-FRI/.
THIS FEATURE WILL RETREAT INTO THE NRN ATLC BY THE WEEKEND...WITH
THE FOCUS SHIFTING TO THE EVOLUTION OF THE CLOSED LOW OVER THE
CENTRAL STATES.

THE ECMWF LIES ON THE WWD SIDE OF THE DETERMINISTIC ENVELOPE SHOWING
A MORE COASTAL TRACK WITH THE ENERGY DROPPING OFFSHORE THE NE COAST
EARLY IN THE PERIOD. HOWEVER THE OVERALL MODEL SPREAD IS PRETTY LOW
WITH THIS FEATURE...WHICH SHOULD SEND A BACKDOOR COLD FRONT INTO THE
REGION ON FRIDAY AND ACCENTUATE A WEST-EAST TEMPERATURE GRADIENT.

THE DOMINANT SYNOPTIC FEATURE DRIVING THE SENSIBLE WEATHER IN
CENTRAL PA THROUGH THE BALANCE OF THE PERIOD WILL BE THE HIGH
AMPLITUDE UPPER-LEVEL RIDGE...WHICH SHOULD EFFECTIVELY BLOCK PCPN
ASSOCD WITH THE CENTRAL US CLOSED LOW FROM REACHING THE
NORTHEAST/MID-ATLC STATES AT LEAST THROUGH THE UPCOMING WEEKEND.

THE OPERATIONAL MODELS AND THEIR ENSEMBLE MEANS HAVE MANY VARIED
SOLUTIONS CONCERNING THE EVENTUAL EWD PROGRESSION OF THE CENTRAL US
CLOSED LOW. IN GENERAL...THERE APPEARS TO BE A SLIGHTLY SLOWER AND
SOUTHWARD TREND IN THE MOST RECENT NON-NCEP MODEL DATA. THE SLOWER
TREND MAKES SENSE GIVEN THAT THE MODELS USUALLY TRY TO BREAK DOWN
THESE PATTERNS TOO QUICKLY. THE LATE-SPRING/EARLY MAY TIMEFRAME IS
ALSO A CLIMATALOGICALLY FAVORED PERIOD FOR BLOCKY PATTERNS/CUT-OFF
LOWS. WITH REGARD TO THE EWD MVMT OF THE CLOSED LOW AND CORRESPONDING
CHCS FOR PCPN...WILL UTILIZE AN EVEN BLEND OF AVAILABLE GUIDANCE. THIS
IDEA SEEMS TO FIT THE WPC PREFERENCE OF AN INTERMEDIATE 12Z CANADIAN
OR EC/GEFS MEAN SOLUTION.

&&

.AVIATION /19Z TUESDAY THROUGH SUNDAY/...
THE MAIN BELT OF ANOMALOUS EASTERLY WINDS SHIFTS GRADUALLY SOUTH
TO THE CAROLINAS TONIGHT INTO WEDNESDAY...WHILE AN ANOMALOUS /+2-3
SIGMA/ 500 MB RIDGE AMPLIFIES FROM THE TENNESSEE VALLEY TO EASTERN
CANADA. IN ADDITION...DRIER AIR IS ALREADY BEGINNING TO ADVECT IN
FROM THE EAST...WHICH WILL AID IN RAISING CIGS AND GRADUALLY
DIMINISHING CLOUDS FROM THE EAST THIS AFTERNOON INTO THE OVERNIGHT.
STUBBORN LOWER STRATOCU SHOULD LINGER THE LONGEST /THROUGH 12Z/
IN THE SW WHERE SPOTTY DRIZZLE WILL REMAIN POSS OVERNIGHT /AS PER
THE 4KM NAM AND HRRR - THOUGH THEY HAVE BEEN OVERDOING POTENTIAL
FOR LIGHT PRECIP OVER THE PAST 24 HRS/.

LINGERING LOW CIGS WILL GIVE WAY TO VFR CONDITIONS AREAWIDE ON WED
AS HIGH PRESSURE RIDGE STRENGTHENS OVER THE REGION. THIS WILL
BEGIN AN EXTENDED PERIOD OF EXCELLENT FLYING CONDITIONS.


.OUTLOOK...

WED...LOW CIGS POSS EARLY OVR THE W MTNS...OTHERWISE VFR.

THU-SUN...VFR. NO SIG WX EXPECTED.

&&

.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.

&&

$$
SYNOPSIS...RXR
NEAR TERM...RXR
SHORT TERM...RXR
LONG TERM...STEINBUGL
AVIATION...RXR







AREA FORECAST DISCUSSION

NWS STATE COLLEGE PA

 302 PM EDT TUE APR 30 2013

.SYNOPSIS...
A WEAK AREA OF LOW PRESSURE NEAR THE OUTER BANKS OF NORTH CAROLINA
WILL MAINTAIN A SOUTHEASTERLY FLOW OF MOIST AIR INTO CENTRAL
PENNSYLVANIA TONIGHT...KEEPING CLOUDS AROUND WITH A MENTION OF
DRIZZLE FOR THE SOUTHERN MOUNTAINS. A HIGH AMPLITUDE BLOCKING
RIDGE WILL SET UP ACROSS THE REGION FOR THE SECOND HALF OF THE
WEEK...BRINGING DRY AND MILD WEATHER WHICH IS EXPECTED TO LAST
INTO THE UPCOMING WEEKEND.

&&

.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
THE MAIN BELT OF ANOMALOUS EASTERLIES SHIFTS GRADUALLY SOUTH TO
THE CAROLINAS TONIGHT INTO WEDNESDAY...WHILE AN ANOMALOUS /+2-3
SIGMA/ 500 MB RIDGE AMPLIFIES FROM THE TENNESSEE VALLEY TO EASTERN
CANADA. IN ADDITION...DRIER AIR IS ALREADY BEGINNING TO ADVECT IN
FROM THE EAST...WHICH WILL AID IN RAISING CIGS AND GRADUALLY
DIMINISHING CLOUDS OVERNIGHT FROM THE EAST. STUBBORN STRATOCU
SHOULD LINGER THE LONGEST /THROUGH 12Z/ IN THE SW WHERE SPOTTY
DRIZZLE WILL REMAIN POSS OVERNIGHT /AS PER THE 4KM NAM AND HRRR -
THOUGH THEY HAVE BEEN OVERDOING POTENTIAL FOR LIGHT PRECIP OVER
THE PAST 24 HRS/.

LOW TEMPS WILL BE IN THE 40S...WITH COOLEST READINGS IN THE
NORTHEAST AND EAST WHERE CLOUDS WILL THIN FIRST AND DEWPOINTS
WILL LOWER FIRST.

&&

.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH WEDNESDAY NIGHT/...
ANOMALOUS /+2-3 SIGMA/ 500 MB RIDGE BEGINS TO QUICKLY AMPLIFY
FROM THE TENNESSEE VALLEY TO EASTERN CANADA ON WED. AFTER A CLOUDY
START IN THE SW...SKIES SHOULD BECOME PARTLY CLOUDY EVERYWHERE BY
LATE MORNING WITH SUNSHINE CONTINUING TO INCREASE IN THE
AFTERNOON AS SUBSIDENCE DEEPENS UNDER THE BUILDING HIGH.

HIGH TEMPS WEDNESDAY WILL WARM BY 8-10F COMPARED TO
TUESDAY...WHICH WILL BE NEAR NORMAL ACROSS THE SUSQ VALLEY...AND
5-8F DEGREES ABOVE NORMAL OVER THE NRN AND WESTERN MTNS. LOWS WED
NIGHT WILL BE CHILLY WITH STRENGTHENING HIGH PRESSURE BRINGING
LIGHT WINDS AND DRIER AIR. READINGS WILL BOTTOM OUT IN THE
40S...WITH SOME UPPER 30S POSS IN NORTHEASTERN MTNS.

&&

.LONG TERM /THURSDAY THROUGH TUESDAY/...
THE MEDIUM RANGE MODEL AND ENSEMBLE GUIDANCE SHOWS A HIGHLY
AMPLIFIED 500MB PATTERN THROUGH THE REMAINDER OF THE PERIOD...WITH
AN OMEGA BLOCK DEVELOPING FROM THE CENTRAL/EASTERN CONUS INTO THE
WRN ATLANTIC. FORTUNATELY...THE UPPER RIDGE PORTION OF THE BLOCK
SHOULD SET-UP OVER THE INTERIOR NORTHEAST AND PROVIDE SEVERAL DAYS
OF FAIR AND DRY WEATHER WITH ABOVE NORMAL DAYTIME TEMPS.

THE MODELS ARE USUALLY TOO QUICK TO BREAK DOWN BLOCKING
PATTERNS...WHICH ALSO TEND TO BE MORE FREQUENT IN LATE SPRING.
THEREFORE PREFER AN ECMWF-BASED SOLUTION WITH NO SIGNIFICANT KICKER
SYSTEM NEARBY. ALSO WEIGHTED TEMPERATURES TOWARD A BLEND OF THE
OPERATIONAL AND ENSEMBLE ECMWF MOS PRODUCTS. THE SLIGHT
MARITIME/SELY COMPONENT TO THE WIND FIELD SHOULD KEEP HIGHS NEAR
SEASONAL/EARLY MAY NORMALS.

&&

.AVIATION /19Z TUESDAY THROUGH SUNDAY/...
THE MAIN BELT OF ANOMALOUS EASTERLY WINDS SHIFTS GRADUALLY SOUTH
TO THE CAROLINAS TONIGHT INTO WEDNESDAY...WHILE AN ANOMALOUS /+2-3
SIGMA/ 500 MB RIDGE AMPLIFIES FROM THE TENNESSEE VALLEY TO EASTERN
CANADA. IN ADDITION...DRIER AIR IS ALREADY BEGINNING TO ADVECT IN
FROM THE EAST...WHICH WILL AID IN RAISING CIGS AND GRADUALLY
DIMINISHING CLOUDS FROM THE EAST THIS AFTERNOON INTO THE OVERNIGHT.
STUBBORN LOWER STRATOCU SHOULD LINGER THE LONGEST /THROUGH 12Z/
IN THE SW WHERE SPOTTY DRIZZLE WILL REMAIN POSS OVERNIGHT /AS PER
THE 4KM NAM AND HRRR - THOUGH THEY HAVE BEEN OVERDOING POTENTIAL
FOR LIGHT PRECIP OVER THE PAST 24 HRS/.

LINGERING LOW CIGS WILL GIVE WAY TO VFR CONDITIONS AREAWIDE ON WED
AS HIGH PRESSURE RIDGE STRENGTHENS OVER THE REGION. THIS WILL
BEGIN AN EXTENDED PERIOD OF EXCELLENT FLYING CONDITIONS.


.OUTLOOK...

WED...LOW CIGS POSS EARLY OVR THE W MTNS...OTHERWISE VFR.

THU-SUN...VFR. NO SIG WX EXPECTED.

&&

.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.

&&

$$
SYNOPSIS...RXR
NEAR TERM...RXR
SHORT TERM...RXR
LONG TERM...LAMBERT/STEINBUGL
AVIATION...RXR







AREA FORECAST DISCUSSION

NWS LUBBOCK TX

 1127 AM CDT TUE APR 30 2013

.UPDATE...
ONLY MINOR TWEAKS LIKELY TO THE ONGOING FCST. FOCUS CONTINUES ON
SMALL CHANCE OF ISOLATED HIGH-BASED TSRA THIS AFTERNOON AND EARLY
EVENING ALONG AND JUST EAST OF THE I-27 CORRIDOR. THE WRF-NAM
CONTINUES TO BE THE ONLY MODEL THAT GENERATES ANY MEANINGFUL QPF
WHILE THE RAP BARELY HINTS AT THE POSSIBILITY OF MEASURABLE
PRECIP...AND THE TTU-WRF REMAINS DRY. MODEST NEAR-SFC MOISTURE
VERY SHALLOW PER 12Z KAMA SOUNDING SUGGESTS ANY INSTABILITY LIKELY
RELEASED CLOSER TO 550 MB. PROBABILITY LOOKS SMALL BUT MENTION OF
TSRA REMAINS VALID. ANY SEVERE THREAT LIKELY LIMITED TO WIND.

&&

.AVIATION...
PROBABILITY OF TSRA AT KLBB TOO LOW TO INSERT MENTION IN THE TAF.
SOME INDICATION THAT LOW CLOUDS COULD MOVE INTO THE ROLLING PLAINS FROM
THE SOUTHEAST LATE TONIGHT...AND MAY NEED TO INSERT A MENTION OF
MVFR CIGS AT KCDS. FINALLY...ANOTHER STRONG COLD FRONT TO MOVE
THROUGH THE AREA PROBABLY BETWEEN 12Z AND 18Z WEDNESDAY WITH WINDS
POSSIBLY AROUND 25 KTS SUSTAINED.

&&

.PREV DISCUSSION... /ISSUED 645 AM CDT TUE APR 30 2013/

AVIATION...
THE NOCTURNAL LLJ IS WEAKENING PER TTU SODAR DATA AND SHEAR
SHOULD BE BELOW LLWS CRITERIA BY 12Z OR SHORTLY AFTER.
OTHERWISE...EXPECT SRLY WINDS AT BOTH TERMINALS TODAY WITH PREVAILING
VFR CONDITIONS. THERE IS A SLIM CHANCE OF TSRA AND/OR OUTFLOW WINDS IN
THE VICINITY OF EITHER TERMINAL THIS AFTERNOON AND EVENING...BUT
PROBABILITY WAS DEEMED TOO LOW FOR EVEN A CB MENTION. SFC WINDS
WILL REMAIN BREEZY OVERNIGHT. A STRONG COLD FRONT WILL APPROACH
THE AREA VERY LATE IN THE FORECAST PERIOD.

PREV DISCUSSION... /ISSUED 448 AM CDT TUE APR 30 2013/

SHORT TERM...
200 AM CDT SFC ANALYSIS SHOWS A SFC TROUGH EXTENDING SOUTH INTO ERN
NM FROM A LOW PRESSURE CENTER IN THE ERN DAKOTAS. THERE IS ALSO A
COLD FRONT STRETCHING W-SW ACROSS WRN NE INTO SRN WY AND NRN UT THAT
WILL HAVE A BIG IMPACT ON OUR WX TOMORROW. ALOFT...A LONGWAVE TROUGH
LOCATED ACROSS SW CANADA AND NW CONUS WILL SLOWLY PROGRESS EAST AND
AMPLIFY SOMEWHAT EAST OF THE ROCKIES TODAY...WHILE WTX WILL REMAIN
IN A REGION OF OVERALL WEAK FLOW BETWEEN THE NORTHERN SYSTEM AND A
SMALLER LOW MOVING EAST ALONG THE GULF COAST.

DECENT MOISTURE ADVECTION IS UNDERWAY EAST OF THE SFC TROUGH WITH
MID TO UPPER 50 DEWPOINTS ADVANCING INTO THE ROLLING PLAINS. THERE
WILL BE A SHORT WINDOW FOR SOME LIGHT FOG AROUND SUNRISE AS THE
MOISTURE MOVES ONTO THE CAPROCK...BUT NO MAJOR VISIBILITY CONCERNS
ARE EXPECTED AT THIS TIME.

MAIN FCST CONCERN FOR TODAY WILL THE CONVECTIVE CHANCES. THE DRYLINE
IS EXPECTED TO MIX ACROSS THE CAPROCK BY MID AFTERNOON BUT
INCREASINGLY STRONG AND BACKED FLOW ACROSS THE ROLLING PLAINS SHOULD
PUT A STOP TO IT...WITH SOME UNCERTAINTY WHETHER OR NOT THE DRYLINE
WILL SET UP OFF THE CAPROCK EDGE OR PERHAPS HANG FARTHER WEST AS
INDICATED BY THE 0Z NAM. MOISTURE WILL MIX DEEPLY ON BOTH SIDES OF
THE DRYLINE AS TEMPS WARM INTO THE LOWER 90S. FCST SOUNDINGS SUGGEST
THAT THE ATMOSPHERE WILL BECOME UNCAPPED ALONG AND JUST WEST OF THE
DRYLINE WITH ABOUT 1000 J/KG OF ML CAPE ABOVE HIGH LCLS. WHILE WE
EXPECT THE DRYLINE CIRCULATION TO PROVIDE A ADEQUATE LIFTING
MECHANISM FOR LOW-LVL PARCELS...UPPER-LVL SUPPORT LOOKS PRETTY
NEBULOUS. THERE IS A PROGGED SLIGHT INCREASE IN MID-LVL WINDS TO
AROUND 25 KTS...RESULTING IN A MODEST 20 KTS OR SO OF 0-6 KM BULK
SHEAR. HI-RES MODELS ARE DECIDEDLY MIXED WITH THE DEVELOPMENT OF DEEP
CONVECTION IN VICINITY OF THE DRYLINE...WITH ISOLATED COVERAGE AT
BEST. WE WILL HAVE AN ISOLATED MENTION FROM JUST JUST EAST OF THE
I-27/US 87 CORRIDOR THRU THE AFTERNOON...AND SHIFT THE MENTION EAST
IN THE EVENING WITH AN EXPECT SLOW STORM MOTION TO THE SE. ANY T-STORM
ACTIVITY WILL HAVE DIFFICULTY SURVIVING IN THE MORE STABLE AIR EAST
OF THE DRYLINE AND SHOULD DIE FAIRLY QUICKLY AFTER SUNSET. THE SEVERE
THREAT FROM ANY STORMS WILL BE FAIRLY LOW...ISOLATED STRONG WIND
GUSTS WILL BE POSSIBLE WHILE LARGE HAIL LOOKS VERY UNLIKELY.

THE DRYLINE WILL RETREAT SOME THIS EVENING...BUT THEN HALT AS THE
SFC LOW BEGINS TO MOVE SE AND A PRE-FRONTAL TROUGH MOVES INTO THE
WRN ZONES. IT WILL BE VERY MILD OVERNIGHT WITH TEMPS IN THE 50S AND
60S. THE COLD FRONT SHOULD BE ON THE DOORSTEP OF THE SW TX PANHANDLE
BY 12Z WED.

LONG TERM...
PRIMARY FOCUS IN THE EXTENDED FORECAST REVOLVES AROUND THE IMPACTS
BEHIND ANOTHER STRONG LATE SEASON COLD FRONT THAT WILL MOVE THROUGH
ON WEDNESDAY. STRONG NORTH WINDS...MUCH COLDER TEMPERATURES
/INCLUDING THE POSSIBILITY OF ANOTHER FREEZE OR TWO/ AND A BRIEF
WINDOW FOR PRECIPITATION...INCLUDING LIGHT WINTRY PRECIPITATION...ARE
ALL IN THE FORECAST BETWEEN WEDNESDAY NIGHT AND THURSDAY NIGHT.

THE LARGE SCALE PATTERN WILL FEATURE AN AMPLIFYING TROUGH DIGGING
THROUGH THE INTERMOUNTAIN WEST TOMORROW...THEN EMERGING ACROSS THE
HIGH PLAINS ON THURSDAY BEFORE CUTTING OFF FRIDAY SOMEWHERE ACROSS
THE PLAINS. THE CUTOFF LOW IS THEN PROGGED TO GRADUALLY LIFT
NORTHEASTWARD AWAY FROM THE REGION THROUGH THE WEEKEND THOUGH THE
EXACT LATITUDE AT WHICH THIS OCCURS REMAINS VERY UNCERTAIN. ANOTHER
UPPER TROUGH WILL FOLLOW BY THE EARLY TO MIDDLE PARTS OF NEXT WEEK
THOUGH THE DETAILS WITH THIS NEXT SYSTEM WILL BE TOUGH FOR THE NWP
TO RESOLVE GIVEN THE BLOCKY PATTERN.

OF MAIN CONCERN EARLY ON WILL BE ON THE TIMING OF THE COLD FRONT DUE
IN ON WEDNESDAY. IT APPEARS THE INITIAL NORTHERLY WIND SHIFT WILL
ADVANCE FROM NORTH TO SOUTH ACROSS THE SOUTH PLAINS THROUGH THE
MORNING HOURS...THOUGH JUST A COUPLE OF HOURS OF DIFFERENCE IN
TIMING WILL MAKE A HUGE DIFFERENCE IN HOW WARM ANY PARTICULAR
LOCATION GETS. ATTM...WE CONTINUE TO FAVOR A QUICKER
FROPA...RESULTING IN FORECAST HIGHS ON WEDNESDAY RANGING FROM THE
50S AND LOWER 60S NORTHWEST TO MIDDLE 80S SOUTHEAST. THE INITIAL
PRESSURE GRADIENT AND PRESSURE RISES WILL FAVOR GUSTY WINDS
SUSTAINED AT 20-30 MPH...BUT THE GRADIENT IS PROGGED TO FURTHER
TIGHTEN LATE IN THE DAY AND NOT REALLY BEING TO RELAX UNTIL LATER IN
THE DAY ON THURSDAY. THUS...WE COULD SEE A PROLONGED PERIOD OF
ADVISORY LEVEL WINDS LATE WEDNESDAY INTO THURSDAY AND HAVE
INCREASED WIND SPEEDS IN THE GRIDS THROUGH THIS PERIOD. OF
NOTE...THERE IS A SIGNIFICANT DISPARITY BETWEEN THE MET AND MAV
MOS WIND GUIDANCE WITH THE MET ON THE LOW SIDE /AROUND 25 KTS/ AND
THE MAV ON THE HIGH SIDE /ABOVE 40 KTS/. THINK THE MAV IS A BIT
BULLISH...BUT IT WILL BE A WINDY AND RAW STRETCH REGARDLESS.
THESE STRONG WINDS WILL CARRY IN MUCH COLDER AIR /AND BLDU/ WITH
TEMPERATURES BY THURSDAY MORNING EXPECTED TO BREECH THE FREEZING
MARK ACROSS THE NORTHWEST ZONES...WITH 30S FOUND ACROSS MUCH OF
THE REMAINDER OF THE FA...ASIDE FROM A FEW LOWER 40S ACROSS THE
FAR SOUTHEAST ZONES.

REGARDING PRECIPITATION CHANCES...THEY WILL BE ON THE RISE...AT
LEAST POST-FRONTAL. INITIALLY...ALONG THE FRONT...THERE MAY BE A
SLIM CHANCE OF STORMS ACROSS THE FAR EASTERN ZONES WEDNESDAY
AFTERNOON...THOUGH IF THE QUICKER FROPA COMES TO FRUITION THE
WINDOW FOR SFC BASED STORMS WOULD BE NARROWED IF NOT CLOSED
ALTOGETHER. REGARDLESS...DID MAINTAIN A MINIMAL THUNDER MENTION
ACROSS THE FAR EASTERN ZONES WEDNESDAY AFTERNOON. INSTEAD...THE
BETTER PRECIPITATION CHANCES WILL DEVELOP WEDNESDAY NIGHT INTO
EARLY THURSDAY AS FRONTOGENETIC FORCING AND ISENTROPIC UPGLIDE
INCREASE ABOVE THE CAA NEAR/AT THE SFC. ALTHOUGH THE LARGE SCALE
ASCENT FROM THE PASSING TROUGH WILL ONLY GRAZE THE AREA THE
PREVIOUSLY MENTIONED MECHANISMS SHOULD RESULT IN RAIN SHOWERS
DEVELOPING LATE WEDNESDAY NIGHT /AND FAVORING SPOTS OFF THE
CAPROCK/. THERE MAY EVEN BE A LITTLE ELEVATED INSTABILITY IN PLACE
OFF THE CAPROCK WHICH COULD SUPPORT A CHANCE OF THUNDER TOO.
HOWEVER...THE PRIMARY MODE WILL LIKELY BE RAIN SHOWERS EARLY
ON...BUT PRECIPITATION TYPE MAY GET TRICKY AFTER MIDNIGHT AS
COLDER AIR CONTINUES TO POUR IN. PROGGED SOUNDINGS INDICATE A
SIGNIFICANT WARM LAYER CENTERED BETWEEN 700 AND 800 MB...WITH A
LAYER OF SUB-FREEZING TEMPERATURES NEAR 850 MB THAT STRENGTHENS
AND DEEPENS SOUTHWARD ACROSS THE CAPROCK LATE WEDNESDAY NIGHT.
THUS...WE COULD SEE THE RAIN MIX WITH SLEET AND/OR SNOW AS THE
NIGHT GOES ON ACROSS MUCH OF THE CAPROCK...THOUGH ANY WINTRY
PRECIPITATION SHOULD BE ON THE LIGHT SIDE. PRECIPITATION WILL
GRADUALLY WANE THURSDAY MORNING AS THE LOWER AND MID-LEVEL LIFT
WEAKENS...THOUGH IT WILL TAKE AWHILE FOR CLOUDS TO CLEAR AND HIGHS
WILL STRUGGLE TO MAKE IT INTO THE LOWER 50S /IF THEY DO AT ALL/.
CLEARING SKIES AND WEAKENING WINDS WILL THEN SET THE STAGE FOR
ANOTHER COLD NIGHT THURSDAY NIGHT...WITH SPOTS ON THE CAPROCK
LIKELY TO SEE ANOTHER FREEZE...WITH A FROST ALSO POSSIBLE IN THE
ROLLING PLAINS. PLAN TO HIGHLIGHT THE COLDER
TEMPERATURES...POSSIBLE FREEZES AND POTENTIAL FOR LIGHT WINTRY
PRECIPITATION IN A SPECIAL WEATHER STATEMENT.

AFTER FRIDAY MORNING...TEMPERATURES WILL GRADUALLY MODERATE INTO
EARLY NEXT WEEK. SHOWER/STORM CHANCES MAY ALSO IMPROVE TOWARD THE
FAR END OF THE EXTENDED THOUGH CONFIDENCE IN THIS...LIKE THE
PREDICTABILITY OF THE LARGE SCALE WEATHER PATTERN...REMAINS LOW.
HENCE...HAVE MAINTAINED POPS AROUND 10 PERCENT FROM SUNDAY ONWARD.

FIRE WEATHER...
WHILE THERE IS SOME UNCERTAINTY HOW FAR WEST THE DRYLINE WILL SET UP
THIS AFTERNOON...VERY WARM TEMPS AND DRY AIR WILL RESULT IN RH
VALUES DROPPING BELOW 10 PERCENT ACROSS MUCH OF THE FAR SW TX
PANHANDLE AND WRN SPLNS. WIND SPEEDS WILL NOT BE VERY
STRONG...HOWEVER THEY SHOULD BE IN THE 10 TO 20 MPH RANGE AT THE 20
FOOT LEVEL SUFFICIENT FOR THE ISSUANCE OF A FIRE DANGER STATEMENT.
THIS AREA IS LIKELY TO REMAIN DRY WELL IN TO THE EVENING HOURS...BUT
WIND SPEEDS WILL BE LIGHT.

&&

.PRELIMINARY POINT TEMPS/POPS...
FRIONA        91  50  58  29  50 /   0  10  10  20  10
TULIA         91  54  60  31  51 /  10  10  10  30  20
PLAINVIEW     90  56  65  32  51 /  10  10  10  30  20
LEVELLAND     92  55  71  33  51 /  10  10  10  30  20
LUBBOCK       92  60  71  34  51 /  10  10  10  30  20
DENVER CITY   91  55  82  34  52 /   0  10  10  30  20
BROWNFIELD    92  55  80  34  52 /  10  10  10  30  20
CHILDRESS     93  62  74  39  53 /  10  20  10  50  30
SPUR          91  62  80  37  53 /  20  20  10  40  30
ASPERMONT     93  64  83  41  52 /  10  10  20  50  30

&&

.LUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

07







AREA FORECAST DISCUSSION

NWS BLACKSBURG VA

 200 PM EDT TUE APR 30 2013

.SYNOPSIS...
HIGH PRESSURE ALONG THE MID ATLANTIC COAST WILL PERSIST THROUGH
THE WEEK TO BRING COOL AND CLOUDY CONDITIONS. AN AREA OF LOW
PRESSURE WILL DEVELOP AND LINGER OVER THE GREAT PLAINS...WHICH
COULD AFFECT THE EASTERN UNITED STATES LATE IN THE WEEKEND.

&&

.NEAR TERM /THROUGH TONIGHT/...
AS OF 1215 PM EDT TUESDAY...

MORE BREAKS IN THE CLOUDINESS ARE APPEARING WEST OF THE BLUE
RIDGE...EXCEPT NEAR BOONE NORTH CAROLINA. TEMPERATURES WERE
ADJUSTED DOWNWARD DUE TO THE CONTINUING LOW CLOUDS IN THIS AREA.
LITTLE IF ANY CHANGE HAS BEEN SEEN ON VISIBLE SATELLITE ELSEWHERE.
THE LATEST NAM AND GFS GUIDANCE STILL SHOWS A SMALL AMOUNT OF QPF
ALONG THE WESTERN EDGE OF THE WEDGE...SO THE SLIGHT CHANCE TO
CHANCE POPS WERE HELD IN PLACE. OTHERWISE...NO OTHER SIGNIFICANT
TWEAKS WERE MADE FOR THIS UPDATE.

AS OF 1010 AM EDT TUESDAY...

THE LATEST 12Z RNK SOUNDING SHOWS BOUNDARY LAYER MOISTURE STILL
IN PLACE...BUT IT HAS BECOME SHALLOWER DURING THE PAST 24 HOURS.
THICK CLOUD COVER STILL HOLDS OVER THE PIEDMONT...BUT A FEW BREAKS
ARE SHOWING IN FAR SOUTHWEST VIRGINIA AND SOUTHEAST WEST VIRGINIA.
SOME INSOLATION SHOULD ALLOW HIGH TEMPERATURES TO AT LEAST REACH
THE VALUES REALIZED YESTERDAY. TEMPERATURES WERE STILL HELD ON THE
COOLER SIDE OF GUIDANCE BUT NOT QUITE AS MUCH IN THIS UPDATE.
ALSO...SLIGHT CHANCE POPS WERE EXPANDED A LITTLE MORE ON THE
WESTERN PERIPHERY OF THE WEDGE GIVEN THE LATEST RAP MODEL
SOLUTION. HOWEVER...THERE IS NO INSTABILITY THAT WOULD SUPPORT
MENTION OF THUNDER BASED ON THE MODEL SOUNDINGS...SO JUST LIGHT
RAIN SHOWERS WERE INCLUDED.

BY TONIGHT...THE POTENTIAL FOR LOW CLOUDS AND FOG SHOULD EMERGE
AGAIN OVER THE CWA. WITH AN AREA OF LOW PRESSURE DEVELOPING
ALONG THE SOUTHEAST COAST...AND HIGH PRESSURE REMAINING FIRM OVER
THE NORTHEAST...THE EASTERLY FLOW COULD BE ENHANCED AND FURTHER
STRENGTHEN THE COOL WEDGE. ALTHOUGH POPS WERE KEPT LOW DURING THIS
PERIOD...SOME DRIZZLE IS CERTAINLY POSSIBLE...ESPECIALLY ALONG THE
EASTERN SIDE OF THE BLUE RIDGE.

&&

.SHORT TERM /WEDNESDAY THROUGH FRIDAY NIGHT/...
AS OF 400 AM EDT TUESDAY...

RIDGING...SITUATED ROUGHLY ALONG THE APPALACHIAN CHAIN...WILL BE THE
DOMINANT FEATURE IN THE UPPER LEVELS FOR THE REMAINDER OF THE
WORKWEEK AS A DEEP UPPER LEVEL TROUGH SINKS SOUTHWARD ACROSS THE
ROCKIES...AND EVENTUALLY PINCHES OFF INTO A CLOSED LOW OVER THE
CENTRAL PLAINS ON FRIDAY. MEANWHILE...HIGH PRESSURE WILL REMAIN
WEDGED AGAINST THE EASTERN FACE OF THE APPALACHIANS INTO THE
WEEKEND...RESULTING IN A PERSISTENT NORTHEASTERLY TO EASTERLY WIND
FLOW ACROSS THE AREA THAT WILL CONTINUE TO DRAW COOL MOIST AIR
FROM THE ATLANTIC.

AS SUCH...WE CAN EXPECT SIMILAR WEATHER CONDITIONS EACH DAY THROUGH
THE PERIOD...WITH PATCHY DENSE FOG AND AREAS OF DRIZZLE DEVELOPING
EARLY EACH MORNING...ESPECIALLY ALONG THE BLUE RIDGE AND THE EASTERN
FACES OF OTHER PROMINENT RIDGES. MORNING FOG AND LOW CLOUDS WILL
BURN OFF WITH AFTERNOON HEATING...MAKING FOR PARTLY TO MOSTLY CLOUDY
SKIES DURING EACH AFTERNOON. MAY SEE A FEW SHOWERS DEVELOP EACH
AFTERNOON AND EVENING AS SUBTLE DISTURBANCES RIDE ALONG THE EDGE OF
THE UPPER RIDGE. SHOWER ACTIVITY MAY BE ENHANCED BY THE OROGRAPHIC
LIFT OF EASTERLY FLOW INTO THE MOUNTAINS...BUT OTHERWISE DO NOT SEE
ANY SPECIFIC FEATURE THAT WILL CAUSE ORGANIZED RAINFALL. ANY SHOWER
ACTIVITY WILL DIMINISH DURING LATE EVENING AS DAYTIME HEATING
ENDS...WITH A REDEVELOPMENT OF LOW CLOUDS AND PATCHY FOG/DRIZZLE
LATER IN THE OVERNIGHT.

THE FLOW OFF OF THE ATLANTIC WILL MAINTAIN SLIGHTLY COOL CONDITIONS
FOR MUCH OF THE AREA...WITH AFTERNOON HIGHS SOME 3 TO 5 DEGREES
BELOW NORMAL EACH DAY...GENERALLY REACHING INTO THE MID TO UPPER
60S. PORTIONS OF THE MOUNTAIN EMPIRE AND SOUTHEAST WEST VIRGINIA...
LOCATIONS AT THE VERY EDGE OF THE HIGH PRESSURE WEDGE...ARE EXPECTED
TO BE CLOSE TO NORMAL FOR HIGHS. MORNING LOWS WILL BE IN THE UPPER
40S TO LOW 50S WEDNESDAY AND THURSDAY NIGHT...BUT WILL DIP COOLER
FRIDAY NIGHT AS THE UPPER RIDGE BEGINS TO BREAK DOWN...AND WILL
THEREFORE FALL INTO THE LOW 40S NORTH TO UPPER 40S SOUTH.

&&

.LONG TERM /SATURDAY THROUGH MONDAY/...
AS OF 258 PM EDT MONDAY...

THE GYRE OVER THE CANADIAN MARITIMES WILL EVENTUALLY ERODE THE OMEGA
BLOCK INTO A REX...AS A PIECE OF THIS VORTEX WILL ACTUALLY BREAK
FREE AND HEAD SOUTHWEST. NONETHELESS EXPECT SIMILAR WEDGE CONDS
THROUGH THE WEEKEND. THE ECMWF/GFS HAVE HAD A DIFFICULT TIME
RESOLVING AN UPPER DISTURBANCE CROSSING THE LOWER MISSISSIPPI RIVER
VALLEY EARLY NEXT WEEK. THE 12Z GFS WANTS TO BRING THIS SYSTEM
ACROSS THE MOUNTAINS AND INTO THE MID ATLANTIC...WHEREAS THE ECMWF
IS MORE NORTH AND WEST WITH ITS TRACK. IT DOES APPEAR AS THOUGH THIS
STRONG UPPER LOW WILL FINALLY BREAK DOWN THE STRONG UPPER
HIGH...LEADING TO A WARMUP WITH MORE SUNSHINE FINALLY NEXT WEEK.

&&

.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
AS OF 200 PM EDT TUESDAY...

FLYING CONDITIONS HAVE SLIGHTLY IMPROVED DURING THE DAY...AS
CEILINGS HAVE RISEN TOWARD MVFR FOR MOST SITES...AND EVEN TO VFR
AT LWB AND BLF. THERE IS ENOUGH CONFIDENCE THAT THIS PATTERN WILL
HOLD THROUGH THIS AFTERNOON...ALTHOUGH SOME FLUCTUATIONS IN
CEILINGS ARE POSSIBLE. EAST TO SOUTHEAST WINDS WILL PUMP MORE
MARINE MOISTURE INTO THE BOUNDARY LAYER TONIGHT. ALL MODEL
GUIDANCE SHOWS HIGH PRESSURE OFFSHORE OF THE NEW ENGLAND
STATES...AND A DEVELOPING LOW PRESSURE AREA OVER THE SOUTHEAST
COAST...WHICH WILL ACT TOGETHER TO ENHANCE THE EXISTING COOL
WEDGE. AS A RESULT...IT APPEARS THERE IS HIGH CONFIDENCE OF MORE
LIFR/IFR CEILINGS AND VISIBILITIES...WITH THE WORST CONDITIONS
EXPECTED DURING EARLY WEDNESDAY MORNING. CEILINGS SHOULD GRADUALLY
IMPROVE TO MVFR LATE IN THE MORNING ONCE ENOUGH DAYTIME HEATING
AND BOUNDARY LAYER MIXING CAN OCCUR.

THE PERSISTENT COOL WEDGE SHOULD CONTINUE TO HOLD THROUGH
THURSDAY...WITH MORE LIFR/IFR CONDITIONS POSSIBLE DURING THE
NIGHT...AND SLOW IMPROVEMENT TO MVFR IN THE DAY. BY FRIDAY...THE
MODELS HINT THAT HIGH PRESSURE MAY BUILD OVERHEAD TO ALLOW A
DRIER NORTHEAST WIND THAT WOULD SLOWLY ERODE THE WEDGE...AND
BRING BETTER FLYING WEATHER BY THE END OF THIS WEEK. MEANWHILE...A
LOW PRESSURE SYSTEM OVER THE GREAT PLAINS WILL SLOWLY ARRIVE FROM
THE WEST. THE TRACK OF THIS SYSTEM AND ANY IMPACT TO THE TAF
SITES THIS WEEKEND IS QUITE LOW IN CONFIDENCE...DUE TO MAJOR
DIFFERENCES IN THE GFS AND ECMWF SOLUTIONS.

&&

.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.

&&

$$
SYNOPSIS...PW
NEAR TERM...PW
SHORT TERM...NF
LONG TERM...KM
AVIATION...PW




AREA FORECAST DISCUSSION

NWS BLACKSBURG VA

 1217 PM EDT TUE APR 30 2013

.SYNOPSIS...
HIGH PRESSURE ALONG THE MID ATLANTIC COAST WILL PERSIST THROUGH
THE WEEK TO BRING COOL AND CLOUDY CONDITIONS. AN AREA OF LOW
PRESSURE WILL DEVELOP AND LINGER OVER THE GREAT PLAINS...WHICH
COULD AFFECT THE EASTERN UNITED STATES LATE IN THE WEEKEND.

&&

.NEAR TERM /THROUGH TONIGHT/...
AS OF 1215 PM EDT TUESDAY...

MORE BREAKS IN THE CLOUDINESS ARE APPEARING WEST OF THE BLUE
RIDGE...EXCEPT NEAR BOONE NORTH CAROLINA. TEMPERATURES WERE
ADJUSTED DOWNWARD DUE TO THE CONTINUING LOW CLOUDS IN THIS AREA.
LITTLE IF ANY CHANGE HAS BEEN SEEN ON VISIBLE SATELLITE ELSEWHERE.
THE LATEST NAM AND GFS GUIDANCE STILL SHOWS A SMALL AMOUNT OF QPF
ALONG THE WESTERN EDGE OF THE WEDGE...SO THE SLIGHT CHANCE TO
CHANCE POPS WERE HELD IN PLACE. OTHERWISE...NO OTHER SIGNIFICANT
TWEAKS WERE MADE FOR THIS UPDATE.

AS OF 1010 AM EDT TUESDAY...

THE LATEST 12Z RNK SOUNDING SHOWS BOUNDARY LAYER MOISTURE STILL
IN PLACE...BUT IT HAS BECOME SHALLOWER DURING THE PAST 24 HOURS.
THICK CLOUD COVER STILL HOLDS OVER THE PIEDMONT...BUT A FEW BREAKS
ARE SHOWING IN FAR SOUTHWEST VIRGINIA AND SOUTHEAST WEST VIRGINIA.
SOME INSOLATION SHOULD ALLOW HIGH TEMPERATURES TO AT LEAST REACH
THE VALUES REALIZED YESTERDAY. TEMPERATURES WERE STILL HELD ON THE
COOLER SIDE OF GUIDANCE BUT NOT QUITE AS MUCH IN THIS UPDATE.
ALSO...SLIGHT CHANCE POPS WERE EXPANDED A LITTLE MORE ON THE
WESTERN PERIPHERY OF THE WEDGE GIVEN THE LATEST RAP MODEL
SOLUTION. HOWEVER...THERE IS NO INSTABILITY THAT WOULD SUPPORT
MENTION OF THUNDER BASED ON THE MODEL SOUNDINGS...SO JUST LIGHT
RAIN SHOWERS WERE INCLUDED.

BY TONIGHT...THE POTENTIAL FOR LOW CLOUDS AND FOG SHOULD EMERGE
AGAIN OVER THE CWA. WITH AN AREA OF LOW PRESSURE DEVELOPING
ALONG THE SOUTHEAST COAST...AND HIGH PRESSURE REMAINING FIRM OVER
THE NORTHEAST...THE EASTERLY FLOW COULD BE ENHANCED AND FURTHER
STRENGTHEN THE COOL WEDGE. ALTHOUGH POPS WERE KEPT LOW DURING THIS
PERIOD...SOME DRIZZLE IS CERTAINLY POSSIBLE...ESPECIALLY ALONG THE
EASTERN SIDE OF THE BLUE RIDGE.

&&

.SHORT TERM /WEDNESDAY THROUGH FRIDAY NIGHT/...
AS OF 400 AM EDT TUESDAY...

RIDGING...SITUATED ROUGHLY ALONG THE APPALACHIAN CHAIN...WILL BE THE
DOMINANT FEATURE IN THE UPPER LEVELS FOR THE REMAINDER OF THE
WORKWEEK AS A DEEP UPPER LEVEL TROUGH SINKS SOUTHWARD ACROSS THE
ROCKIES...AND EVENTUALLY PINCHES OFF INTO A CLOSED LOW OVER THE
CENTRAL PLAINS ON FRIDAY. MEANWHILE...HIGH PRESSURE WILL REMAIN
WEDGED AGAINST THE EASTERN FACE OF THE APPALACHIANS INTO THE
WEEKEND...RESULTING IN A PERSISTENT NORTHEASTERLY TO EASTERLY WIND
FLOW ACROSS THE AREA THAT WILL CONTINUE TO DRAW COOL MOIST AIR FROM
THE ATLANTIC.

AS SUCH...WE CAN EXPECT SIMILAR WEATHER CONDITIONS EACH DAY THROUGH
THE PERIOD...WITH PATCHY DENSE FOG AND AREAS OF DRIZZLE DEVELOPING
EARLY EACH MORNING...ESPECIALLY ALONG THE BLUE RIDGE AND THE EASTERN
FACES OF OTHER PROMINENT RIDGES. MORNING FOG AND LOW CLOUDS WILL
BURN OFF WITH AFTERNOON HEATING...MAKING FOR PARTLY TO MOSTLY CLOUDY
SKIES DURING EACH AFTERNOON. MAY SEE A FEW SHOWERS DEVELOP EACH
AFTERNOON AND EVENING AS SUBTLE DISTURBANCES RIDE ALONG THE EDGE OF
THE UPPER RIDGE. SHOWER ACTIVITY MAY BE ENHANCED BY THE OROGRAPHIC
LIFT OF EASTERLY FLOW INTO THE MOUNTAINS...BUT OTHERWISE DO NOT SEE
ANY SPECIFIC FEATURE THAT WILL CAUSE ORGANIZED RAINFALL. ANY SHOWER
ACTIVITY WILL DIMINISH DURING LATE EVENING AS DAYTIME HEATING
ENDS...WITH A REDEVELOPMENT OF LOW CLOUDS AND PATCHY FOG/DRIZZLE
LATER IN THE OVERNIGHT.

THE FLOW OFF OF THE ATLANTIC WILL MAINTAIN SLIGHTLY COOL CONDITIONS
FOR MUCH OF THE AREA...WITH AFTERNOON HIGHS SOME 3 TO 5 DEGREES
BELOW NORMAL EACH DAY...GENERALLY REACHING INTO THE MID TO UPPER
60S. PORTIONS OF THE MOUNTAIN EMPIRE AND SOUTHEAST WEST VIRGINIA...
LOCATIONS AT THE VERY EDGE OF THE HIGH PRESSURE WEDGE...ARE EXPECTED
TO BE CLOSE TO NORMAL FOR HIGHS. MORNING LOWS WILL BE IN THE UPPER
40S TO LOW 50S WEDNESDAY AND THURSDAY NIGHT...BUT WILL DIP COOLER
FRIDAY NIGHT AS THE UPPER RIDGE BEGINS TO BREAK DOWN...AND WILL
THEREFORE FALL INTO THE LOW 40S NORTH TO UPPER 40S SOUTH.

&&

.LONG TERM /SATURDAY THROUGH MONDAY/...
AS OF 258 PM EDT MONDAY...

THE GYRE OVER THE CANADIAN MARITIMES WILL EVENTUALLY ERODE THE OMEGA
BLOCK INTO A REX...AS A PIECE OF THIS VORTEX WILL ACTUALLY BREAK
FREE AND HEAD SOUTHWEST. NONETHELESS EXPECT SIMILAR WEDGE CONDS
THROUGH THE WEEKEND. THE ECMWF/GFS HAVE HAD A DIFFICULT TIME
RESOLVING AN UPPER DISTURBANCE CROSSING THE LOWER MISSISSIPPI RIVER
VALLEY EARLY NEXT WEEK. THE 12Z GFS WANTS TO BRING THIS SYSTEM
ACROSS THE MOUNTAINS AND INTO THE MID ATLANTIC...WHEREAS THE ECMWF
IS MORE NORTH AND WEST WITH ITS TRACK. IT DOES APPEAR AS THOUGH THIS
STRONG UPPER LOW WILL FINALLY BREAK DOWN THE STRONG UPPER
HIGH...LEADING TO A WARMUP WITH MORE SUNSHINE FINALLY NEXT WEEK.

&&

.AVIATION /16Z TUESDAY THROUGH SATURDAY/...
AS OF 740 AM EDT TUESDAY...

POOR AVIATION CONDITIONS EXPECTED TO PERSIST THROUGH TAF VALID
PERIOD AS A MID-ATLANTIC SFC HIGH PERSISTS WITH A COOL...EASTERLY
MARITIME FLOW INTO THE CWA. ANY EROSION OF THE WEDGE DURING
DIURNAL HEATING WILL FILL BACK IN OVERNIGHT...WITH PERHAPS EVEN A
BETTER SURGE TONIGHT AS COMPARED TO THIS MORNING AS THE CRUX OF
THE MARITIME AIR MASS SETTLES ACROSS THE REGION. EXPECT IFR-LIFR
CIGS AND MOSTLY MVFR-OCCASIONALLY IFR VSBYS TO PREVAIL AT MANY OF
THE TAF SITES THROUGH MID-MORNING...WITH IMPROVEMENT ONLY TO MVFR
CIGS AT BEST 15Z-04Z. VSBYS SHOULD IMPROVE TO VFR AT MOST SITES AS
THE CIGS LIFT INTO THE MVFR CATEGORY...BEFORE CONDITIONS
DETERIORATE AFTER MIDNIGHT BACK TO IFR-LIFR CIGS AND MVFR-IFR
VSBYS AGAIN. THE EXCEPTION WILL BE BLF...WHICH WILL REMAIN ON THE
PERIPHERY OF THE WEDGE AND WILL HAVE LESS POTENTIAL FOR IFR/LIFR
CIGS/VSBYS THROUGH THIS TAF VALID PERIOD. WINDS WILL REMAIN NE-E
5-8KTS THROUGH THE TAF VALID PERIOD...WITH LOW END GUSTS POSSIBLE
15Z-22Z LYH AND DAN. ANY TSRA SHOULD REMAIN WEST OF THE CWA AND
NOT AFFECT ANY OF THE RNK TAF SITES.

EXTENDED AVIATION DISCUSSION...PERHAPS SLIGHTLY IMPROVED AVIATION
CONDITIONS BY THE END OF THE WEEK INTO THE FIRST HALF OF THE
WEEKEND WITH ENOUGH DRYING FROM THE NE TO ALLOW FOR A BRIEF RETURN
TO VFR FOR THURSDAY INTO FRIDAY...IF THE SFC AND UPPER HIGH CAN
MOVE OVERHEAD. THIS WILL SHUNT THE DEEPER MOISTURE INTO THE SE
STATES. RETURN FLOW SHOULD BRING MOISTURE BACK NORTH BY SATURDAY
OR SUNDAY AHEAD OF A VERY SLOW MOVING OCCLUDED FRONT/CLOSED UPPER
LOW TO THE WEST. THIS MAY RESULT IN A RETURN OR CONTINUATION OF
MVFR CIGS...BUT CONSIDERABLE MODEL RUN-TO-RUN CONSISTENCY DOES NOT
ALLOW FOR MUCH RELIABILITY IN FORECAST CONDITIONS THAT FAR OUT AT
THIS TIME.

&&

.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.

&&

$$
SYNOPSIS...PW
NEAR TERM...PW
SHORT TERM...NF
LONG TERM...KM
AVIATION...RAB