Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 05/11/13
AREA FORECAST DISCUSSION
NWS TUCSON AZ
910 AM MST THU MAY 9 2013
.SYNOPSIS...A LOW PRESSURE SYSTEM OVER THE AREA WILL BRING A CHANCE
OF AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS ESPECIALLY EAST
OF TUCSON THROUGH SATURDAY. EXPECT COOLER THAN NORMAL DAYTIME
TEMPERATURES THIS AFTERNOON AND FRIDAY. DRY CONDITIONS WITH A STRONG
WARMING TREND WILL THEN OCCUR SUNDAY THROUGH WEDNESDAY.
&&
.DISCUSSION...VISIBLE SATELLITE IMAGERY AND SURFACE OBSERVATIONS
INDICATE CLEAR SKIES ACROSS SE AZ AT THIS TIME WITH THE EXCEPTION OF
A FEW CUMULOFORM CLOUDS IN THE VICINITY OF THE WHITE MOUNTAINS.
09/12Z KTWC SOUNDING TOTAL PRECIP WATER VALUE WAS NEAR 0.65 INCH...
WHICH IS AN INCREASE OF NEARLY 0.15 INCH VERSUS 24 HOURS AGO.
BLENDED TOTAL PRECIP WATER IMAGERY PRODUCT VALID 1359Z YIELDED
VALUES RANGING FROM 0.45 INCH ACROSS MUCH OF COCHISE COUNTY TO
NEARLY 0.60 INCH ACROSS FAR WRN PIMA COUNTY.
UPPER LEVEL TROUGH AXIS EXTENDED FROM CENTRAL NEBRASKA SOUTHWESTWARD
ACROSS SRN UTAH...THEN WESTWARD INTO CENTRAL CALIFORNIA. AS THE
TROUGH AXIS MOVES SEWD LATER TODAY...DIFFLUENT FLOW ALOFT IN
COMBINATION WITH ADEQUATE MOISTURE SHOULD PRODUCE ISOLATED TO
SCATTERED SHOWERS ESPECIALLY ACROSS THE WHITE MOUNTAINS. THE 09/14Z
RUC HRRR PROGGED PRECIP ECHOES TO DEVELOP BY 19Z MAINLY ACROSS THE
CATALINA/GALIURO/PINALENO MOUNTAINS BETWEEN TUCSON AND SAFFORD. BY
MID AFTERNOON THE BULK OF CELLS AS PROGGED VIA THE RUC HRRR IS
EXPECTED TO BE ACROSS NRN GREENLEE/GRAHAM/NRN COCHISE COUNTIES.
AT ANY RATE...THE INHERITED OFFICIAL FORECAST DEPICTS A CHANCE OF
SHOWERS AND THUNDERSTORMS THIS AFTERNOON AND THIS EVENING...MAINLY
ACROSS THE WHITE MOUNTAINS. THERE IS A SLIGHT CHANCE OF SHOWERS AND
THUNDERSTORMS THIS AFTERNOON AND THIS EVENING MAINLY NEAR THE
MOUNTAINS OF GRAHAM AND COCHISE COUNTIES...AS WELL AS NEAR THE
CATALINA/RINCON MOUNTAINS JUST EAST OF TUCSON.
OTHERWISE...HIGH TEMPS THIS AFTERNOON WILL BE ABOUT 6-10 DEGS F
COOLER THAN NORMAL.
BASED ON RECEIPT OF THE 09/12Z NAM AND AFOREMENTIONED RUC HRRR...
SEE NO REASON TO MAKE ANY CHANGES TO THE OFFICIAL FORECAST AT THIS
TIME. PLEASE REFER TO THE PREVIOUS DISCUSSION SECTION FOR ADDITIONAL
DETAIL.
&&
.PREV DISCUSSION /215 AM MST THU MAY 9 2013/...ON FRIDAY...MODELS
ARE SIMILAR WITH UPPER LOW OVER NORTHERN SONORA WITH PRECIPITABLE
WATER VALUES ARE PROGGED ACROSS THE AREA TO BE IN THE 0.50"-0.75"
RANGE. AFTERNOON/EVENING MID-LEVEL NE FLOW WILL BE IN THE 15-20 KT
RANGE...WHICH WILL BE ENOUGH TO SEE STORMS PROPAGATE OFF THE
MOUNTAINS INTO THE VALLEYS...ESPECIALLY IN THE EVENING. HAVE
INCREASED POPS FROM TUCSON EAST TO SHOW BETTER CONFIDENCE. MAIN
THREAT IN THE VALLEYS WILL BE GUSTY WINDS...UP TO 40 MPH...NEAR
STORMS AND BLOWING DUST.
SATURDAY...SOME DRIER AIR PUSHES IN THE FROM THE NORTHEAST WITH
UPPER LOW CENTERED OVER SOUTHERN SONORA MEXICO. THIS WILL RESULT IN
LESS AREAL COVERAGE IN STORMS FROM TUCSON EAST.
SUNDAY THROUGH TUESDAY...UPPER LOW MEANDERS OVER SOUTHERN SONORA.
ENOUGH RESIDUAL MOISTURE HANGING AROUND FOR A SLIGHT CHANCE OF
MAINLY MOUNTAIN STORMS. CONFIDENCE NOT OVERLY HIGH SO AT THIS TIME
KEPT POPS BELOW 10%...THUS NO MENTION IN THE ZONES.
WEDNESDAY...UPPER HIGH BUILDS OVER THE AREA.
TEMPERATURES WILL REMAIN PLEASANTLY COOL TODAY AND FRIDAY THEN
WARMUP COMMENCES IN EARNEST THIS WEEKEND WHICH WILL CONTINUE THROUGH
NEXT WEEK.
&&
.AVIATION...ISOLD-SCT -TSRA/-SHRA MAINLY FROM THE CATALINA AND
RINCON MOUNTAINS JUST EAST OF KTUS EASTWARD TO THE NEW MEXICO BORDER
THIS AFTERNOON AND THIS EVENING. BRIEF WIND GUSTS TO AROUND 40 KTS
MAY POTENTIALLY OCCUR NEAR THUNDERSTORMS. OTHERWISE...SKC THIS
MORNING BECOMING FEW-SCT CLOUDS AT 6-10K FT AGL THIS AFTERNOON AND
CONTINUING INTO THRU EARLY FRIDAY MORNING OR 10/12Z. SURFACE WIND
THIS AFTERNOON WLY/SWLY 10-18 KTS WITH GUSTS TO NEAR 25 KTS...
STRONGEST WIND EAST AND SOUTH OF KTUS. OTHERWISE...SURFACE WIND
GENERALLY LESS THAN 10 KTS. AVIATION DISCUSSION NOT UPDATED FOR TAF
AMENDMENTS.
&&
.FIRE WEATHER...THERE IS A CHANCE OF AFTERNOON AND EVENING SHOWERS
AND THUNDERSTORMS ESPECIALLY EAST OF TUCSON THROUGH SATURDAY. THERE
IS THE POTENTIAL FOR GUSTY WINDS ASSOCIATED WITH THUNDERSTORMS...
PARTICULARLY FRIDAY AFTERNOON AND FRIDAY EVENING...AS A LOW PRESSURE
SYSTEM MOVES SOUTHEAST OF THE AREA. FIELD CREWS ARE ENCOURAGED TO
MONITOR THE LATEST FORECASTS REGARDING THIS SCENARIO. OTHERWISE...
COOLER-THAN-NORMAL DAYTIME TEMPERATURES WILL PREVAIL THIS AFTERNOON
AND FRIDAY. GUSTY EAST TO SOUTHEAST WINDS ARE FORECAST ON SATURDAY.
HOWEVER...AT THIS TIME APPEARS THAT CRITICAL FIRE WEATHER THRESHOLDS
WILL NOT OCCUR. THEREAFTER...EXPECT DRY CONDITIONS SUNDAY THROUGH
WEDNESDAY WITH A STRONG WARMING TREND.
&&
.TWC WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...YOUTUBE...AND AT WEATHER.GOV/TUCSON
BF
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
256 PM MDT THU MAY 9 2013
.SHORT TERM...(THIS EVENING THROUGH FRIDAY NIGHT)
ISSUED AT 247 PM MDT THU MAY 9 2013
ELONGATED UPPER LOW FROM SRN CA ACROSS THE 4 CORNERS TO ERN CO WAS
GETTING STRETCHED APART THIS AFTERNOON...AS THE EASTERN PORTION
MOVES INTO THE PLAINS WHILE THE WESTERN PORTION DROPS SOUTHWARD.
CONVECTION WAS A LITTLE SLOW GETTING GOING TODAY...BUT RECENT KGJX
RADAR SHOWED ECHOES BUILDING ALONG THE TAVAPUTS/ROAN PLATEAUS TO THE
FLATTOPS...AND OVER THE CENTRAL AND SOUTHERN MTNS. INSTABILITY
LIKELY THE DRIVING FORCE THOUGH RAP MODEL INDICATED SOME 700-500 MB
LAYER CONVERGENCE SOUTH OF I-70 AND UNDER THE DEFORMATION/UPPER LOW
AXIS ALOFT. ISOLATED THUNDERSTORMS WILL BE POSSIBLE WITH GUSTY WINDS
AND PERHAPS SOME GRAUPEL. WILL KEEP THE CURRENT WINTER HIGHLIGHTS
GOING THOUGH PRECIPITATION LIKELY TO BE QUITE VARIABLE GIVEN THE
CONVECTIVE NATURE OF THE SHOWERS.
THE DEFORMATION ZONE SINKS SOUTH OF OUR AREA THIS EVENING AND
TONIGHT. WITH ITS EXIT AND THE LOSS OF DAYTIME HEATING...EXPECT
SHOWERS TO DIMINISH BY LATE EVENING.
A SHORTWAVE DISTURBANCE DROPPING DOWN ACROSS WRN MT THIS AFTERNOON
WILL REACH OUR FORECAST AREA BY FRI MORNING. NE UT/NW CO SHOULD SEE
CLOUDS BACK ON THE INCREASE BY SUNRISE. WEAK MOISTURE TRANSPORT IN
THE NORTHERN FLOW ALONG THIS PASSING WEAK DISTURBANCE AND DAYTIME
INSTABILITY SHOULD TRIGGER A ROUND OF AFTERNOON SCATTERED SHOWERS AND
ISOLATED THUNDERSTORMS FRIDAY AFTERNOON...MAINLY OVER THE HIGHER
TERRAIN. SNOW WILL GENERALLY BE CONFINED TO ABOVE 9500-10K FT. HIGH
TEMPS FRIDAY WILL BE WARMER THAN TODAY.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 247 PM MDT THU MAY 9 2013
A HIGHLY AMPLIFIED PATTERN THROUGH THE WEEKEND FLATTENS EARLY NEXT
WEEK. THERE IS HIGH FORECAST CONFIDENCE THROUGH MONDAY...THEN MODELS
SHOW INCREASING SPREAD IN FORECAST DETAILS.
A POSITIVELY TILTED RIDGE AXIS AMPLIFIES FROM THE EASTERN PACIFIC
INTO THE NORTHERN ROCKIES. THEN SLOWLY PROGRESSES UNTIL IT IS
OVERHEAD ON MONDAY. A PORTION OF THE LOW PRESSURE SYSTEM THAT
BROUGHT SHOWERS ON WEDNESDAY INTO THURSDAY IS CUTOFF IN SONORA
MEXICO. NEAR NORMAL TEMPERATURES ON SATURDAY WILL RISE WELL ABOVE
NORMAL BY MONDAY. THE WARMING AFTERNOON TEMPERATURES AND MARGINAL
MOISTURE LOOK TO OVERCOME SUBSIDENCE ON SATURDAY FOR SCATTERED
MAINLY MOUNTAIN THUNDERSTORMS. INCREASING SUBSIDENCE ON SUNDAY AND
MONDAY WITH MOISTURE DIMINISHING DUE TO CONVECTIVE VENTILATION
DIMINISH THE CHANCES OF MOUNTAIN SHOWERS. MONDAY AFTERNOON
TEMPERATURES WILL RISE ABOUT 10 DEGREES ABOVE NORMAL.
ON MONDAY A TROUGH WORKS INTO BC-WASHINGTON AND LIFTS THROUGH THE
NORTHERN ROCKIES ON TUESDAY. THIS BREAKS DOWN THE LOCAL RIDGE AND
ALSO ENTRAINS THE SONORA LOW...BOTH OF WHICH MAY INCREASE DIURNAL
THUNDERSTORM COVERAGE FOR TUESDAY INTO WEDNESDAY. BY THURSDAY BOTH
THE EC AND GFS ARE DIGGING A SHALLOW TROUGH ALONG THE WEST COAST
THAT MAY THREATEN INCREASED SHOWERS TOWARDS THE NEXT WEEKEND.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z FRIDAY EVENING)
ISSUED AT 247 PM MDT THU MAY 9 2013
SCATTERED TO NUMEROUS RAIN/SNOW SHOWERS OVER THE WRN CO AND SE UT
MTNS THIS AFTERNOON WILL DIMINISH THIS EVENING. ISOLATED
THUNDERSTORMS ARE POSSIBLE. STORM MOTION WILL BE TO THE WEST
SOUTHWEST AND POSSIBLY AFFECT THE WEST CENTRAL CO TAF SITES PRIOR TO
03Z. IN GENERAL...THOUGH...VFR CONDITIONS SHOULD BE PRESENT THROUGH
18Z FRI. SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS WILL DEVELOP
OVER THE HIGHER TERRAIN AGAIN FRI AFTERNOON.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...WINTER WEATHER ADVISORY UNTIL 6 PM MDT THIS EVENING FOR COZ009-
010-013-018-019.
WINTER STORM WARNING UNTIL 6 PM MDT THIS EVENING FOR COZ012.
UT...NONE.
&&
$$
SHORT TERM...JAD
LONG TERM...JOE
AVIATION...JAD
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
1022 AM MDT THU MAY 9 2013
.UPDATE...
ISSUED AT 1022 AM MDT THU MAY 9 2013
LET THE DENSE FOG ADVISORY FOR THE CRAIG-HAYDEN AREAS EXPIRE AT 10
AM AS VISIBILITY AT THE ASOS SITES IMPROVED AND FOG DISSIPATED.
ELONGATED UPPER LOW REMAINS STRETCHED ACROSS SRN UT AND SRN CO
THIS MORNING. SNOW ACTIVITY APPEARS TO BE IN A BIT OF A LULL AT
MID-MORNING ESPECIALLY ACROSS THE NRN MTNS/FLATTOPS AND HAVE
KNOCKED DOWN POPS THERE FOR THE REST OF THIS MORNING. REGIONAL
RADAR SHOWED PRECIPITATION APPROACHING THE CONTINENTAL DIVIDE IN
EAST TO NORTHEAST FLOW...AND EXPECT CONVECTIVE SNOW SHOWER
ACTIVITY TO ALSO BEGIN INCREASING AT MIDDAY AS INSTABILITY STARTS
TO BE REALIZED WITH DAYTIME HEATING. HIGH RESOLUTION HRRR MODEL
PRECIP FAVORS THE SAN JUAN MTNS...CLOSEST TO THE UPPER
LOW/DEFORMATION AXIS ALOFT. THUS...NO CHANGES TO THE CURRENT
WINTER HIGHLIGHTS FOR MANY WRN CO MTNS THROUGH 6 PM THIS EVENING
THOUGH SNOW/RAIN AMOUNTS LIKELY TO BE QUITE VARIABLE DUE TO THE
SHOWERY NATURE OF THE PRECIPITATION.
&&
.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 412 MDT THU MAY 9 2013
TODAY...THE QUASI-STATIONARY AND ELONGATED LOW PRESSURE SYSTEM
EXTENDING FROM THE CENTRAL PLAINS WEST-SOUTHWEST TO SOUTHERN
CALIFORNIA WILL CONTINUE TO IMPACT THE REGION TODAY. THE
DEFORMATION AXIS ASSOCIATED WITH THIS SYSTEM STRETCHED FROM THE
CENTRAL MOUNTAINS TO THE LA SAL MOUNTAINS IN SOUTHEAST UTAH EARLY
THIS MORNING WHERE PRECIPITATION WAS HEAVIEST. KASE OBSERVATIONS
SHOWED THE SNOW LEVEL HAD LOWERED TO NEAR THE 8 KFT MARK
OVERNIGHT BUT SHOULD REBOUND TO ABOVE 8500 FEET WITH AFTERNOON
WARMING. AS THE DAY PROGRESSES THIS BAND WILL SHIFT SOUTHWARD WITH
THE BEST SNOWFALL MOVING INTO THE SAN JUAN MOUNTAINS DURING THE
AFTERNOON. INSTABILITY WILL CONTINUE TO BRING SNOW TO THE REST OF
THE MOUNTAINS TODAY SO WILL NOT MAKE CHANGES TO GOING HILITES.
VALLEYS WILL SEE SHOWERS FROM TIME TO TIME WHICH WILL KEEP
TEMPERATURES BELOW NORMAL AND UNDERCUT MOS A BIT LIKE PREVIOUS
SHIFTS.
TONIGHT THROUGH SATURDAY...LARGE POLAR VORTEX OVER THE NORTHERN
CANADIAN TERRITORIES WILL KEEP HIGH LATITUDE ENERGY DIRECTED
INTO THE UPPER MID WEST AND EVENTUALLY CARVE OUT A FAIRLY DEEP
TROF OVER THE EASTERN CONUS BY SATURDAY AFTERNOON. WITH ANOTHER
STRONG LOW PRESSURE SYSTEM MOVING INTO THE NORTHEAST PACIFIC
THROUGH THIS TIME...HIGH AMPLITUDE RIDGING WILL EXPAND ACROSS MUCH
OF WESTERN NORTH AMERICA. THIS RIDGE WILL EVENTUALLY BE FOLDED
OVER THE ROCKIES AND BRING DRY AND MUCH WARMER WEATHER BY EARLY
NEXT WEEK. HOWEVER...BEFORE THIS OCCURS INSTABILITY AND WEAK
MOISTURE ADVECTION WILL KEEP UNSETTLED WEATHER IN PLACE OVER OUR
CWA.
BY THIS EVENING...LOW PRESSURE DROPPING INTO THE NORTHERN BAJA
REGION WILL HELP DRAW THE WEAKENING LOW PRESSURE OVER OUR AREA
BACK TO THE SOUTHWEST. ANY FORCING FROM THIS SHEARING LOW PRESSURE
AREA WILL BE REFOCUSED TO THE SOUTH WITH THE NEW ENERGY TO THE
WEST. THE RIDGE WILL TEMPORARILY BUILD IN FROM THE NORTH AS WELL
BUT WILL BE KNOCKED BACK TO THE WEST AS A VIGOROUS WAVE DROPS
THROUGH DEVELOPING TROF OVER THE NORTHERN PLAINS. THEREFORE...
EXPECT SHOWER ACTIVITY TO DROP OFF FAIRLY QUICKLY TOWARDS SUNSET
THIS EVENING WITH COOLER TEMPERATURES AND POSSIBLY SOME PATCHY FOG
FORMING UNDER CLEARING SKIES TOWARD MORNING. A VERY SUBTLE WAVE
WILL BE PUSHED THROUGH THE NORTHERLY FLOW DEVELOPING OVER THE
CENTRAL ROCKIES. WEAK INSTABILITY AND RESIDUAL MOISTURE WILL BE
SUFFICIENT TO SPARK AFTERNOON CONVECTION OVER THE HIGHER TERRAIN.
WEAK SHEAR AND MINIMAL MOISTURE ADVECTION SHOULD KEEP MOST OF THIS
ROOTED TO THE HIGHER ELEVATIONS WITH ONLY A FEW STRAY LIGHT
SHOWERS MOVING INTO THE VALLEYS. WITH RESIDUAL MOISTURE LINGERING
ACROSS THE REGION KEPT TEMPERATURES IN CHECK AND TOWARD THE
LOWER END OF GUIDANCE.
EXPECT THE SHOWERS TO AGAIN QUICKLY FADE BY SUNSET ON FRIDAY ONLY
TO REFORM ONCE AGAIN DURING THE HEATING OF THE DAY ON SATURDAY.
MOISTURE CONTINUES TO DWINDLE SO COVERAGE SHOULD AGAIN BE MORE
FOCUSED ON THE TERRAIN. MID LEVEL TEMPERATURES MAKE A FAIRLY GOOD
JUMP BY SATURDAY AFTERNOON WHICH SHOULD PUSH HIGHS CLOSER TO
NORMAL.
.LONG TERM...(SATURDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 412 MDT THU MAY 9 2013
MODELS SHOWED A STRONG RIDGE OF HIGH PRESSURE BUILDING OVER THE
WEST LATE IN THE WEEK RESULTING IN A STEADY INFLUX OF DRIER AIR
FROM THE NORTHWEST. CONSEQUENTLY...EXPECT LARGELY DIURNAL SHOWERS
AND THUNDERSTORMS TO DIMINISH BY EARLY SUNDAY MORNING WITH A FEW
REIGNITING ALONG THE CONTINENTAL DIVIDE SUNDAY AFTERNOON/EVENING.
FLOW BECOMES MORE ZONAL MONDAY AS THE RIDGE FLATTENS IN RESPONSE
TO A SHORTWAVE TROUGH MOVING ACROSS THE NORTHERN ROCKIES. DAYTIME
HEATING WILL SPARK ANOTHER ROUND OF THUNDERSTORMS MONDAY
AFTERNOON/EVENING.
ECMWF AND GFS DIVERGE A LITTLE BIT TOWARD MIDWEEK WITH THE GFS
GENERATING A SHALLOW TROUGH OVER THE WEST WHILE THE EC FAVORED A
FLAT RIDGE. REGARDLESS...BOTH CONTINUED WITH DIURNAL SHOWER AND
THUNDERSTORM ACTIVITY BOTH TUESDAY AND WEDNESDAY.
TEMPERATURES WILL BE ABOVE NORMAL SUNDAY INTO MIDWEEK AS WARMER
AIR BENEATH THE RIDGE SWEEPS INTO THE AREA AND THEN LINGERS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1022 AM MDT THU MAY 9 2013
IFR/MVFR CIGS AT KEGE/KASE/KMTJ FOLLOWING EARLY MORNING
PRECIPITATION LATE THIS MORNING SHOULD LIFT BY EARLY AFTERNOON AS
VALLEY MIXING OCCURS. VFR SHOULD THEN BE THE GENERAL CONDITION
EXPECTED AT THE TAF SITES THROUGH 03Z...THOUGH MVFR OR EVEN IFR
CONDITIONS WILL BE POSSIBLE FROM TIME TO TIME IN SHOWERS
ESPECIALLY AT KASE. EXPECT MTN TOPS TO BE FREQUENTLY OBSCURED THIS
AFTERNOON. IN ADDITION...ISOLATED THUNDERSTORMS WILL PRODUCE
STRONG...GUSTY AND ERRATIC OUTFLOW WINDS.
SHOWERS DIMINISH OVERNIGHT OVER MUCH OF THE AREA...THOUGH THE SAN
JUAN MOUNTAINS WILL CONTINUE TO SEE LOCALIZED LIGHT SNOW IN THE
HIGHER ELEVATIONS. LOW CLOUDS OR FOG MAY PRODUCE LOCALIZED
MVFR...OR IFR/LIFR VSBY AND CIGS IN THE CENTRAL COLORADO VALLEYS
AFTER MIDNIGHT.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...WINTER WEATHER ADVISORY UNTIL 6 PM MDT THIS EVENING FOR COZ009-
010-013-018-019.
WINTER STORM WARNING UNTIL 6 PM MDT THIS EVENING FOR COZ012.
UT...NONE.
&&
$$
UPDATE...JAD
SHORT TERM...NL/15
LONG TERM...NL
AVIATION...TGJT
AREA FORECAST DISCUSSION
NWS ALBANY NY
1005 PM EDT FRI MAY 10 2013
.SYNOPSIS...
A SLOW MOVING FRONTAL SYSTEM WILL APPROACH THE REGION
TONIGHT...ALLOWING FOR WIDESPREAD SHOWERS ALONG WITH MILD
TEMPERATURES. SHOWERS AND ISOLATED THUNDERSTORMS WILL CONTINUE
THROUGH THE DAY ON SATURDAY AS THE STORM/S COLD FRONT MOVES ACROSS
THE AREA. DRIER AND SOMEWHAT COOLER WEATHER WILL RETURN FOR MOTHER/S
DAY.
&&
.NEAR TERM /THROUGH SATURDAY/...
AS OF 1005 PM EDT...A BAND OF RAIN SHOWERS CONTINUES TO SLOWLY
PROGRESS EASTWARD ACROSS CENTRAL NY. WHILE THERE HAD BEEN A LOT OF
LTG ACTIVITY EARLIER...THE SHOWERS HAVE RUN INTO A MORE STABLE
AIRMASS...AND WITH THE LOSS OF DAYTIME HEATING...THE THREAT FOR
THUNDER HAS BEEN PRETTY MUCH ENDED. WILL ALLOW FOR A SLIGHT CHC OF
THUNDER FOR THE NEXT HOUR OR SO ACROSS THE WESTERN
ADIRONDACKS...OTHERWISE...WILL NOT MENTION THUNDER FOR THE
OVERNIGHT PERIOD.
THE LATEST 00Z 3KM HRRR CONTINUES TO SHOW THE ACTIVITY MAKING IT
INTO OUR WESTERN ZONES OVER THE NEXT HOUR OR TWO...AND TOWARDS THE
CAPITAL REGION BY MIDNIGHT...AND WESTERN NEW ENGLAND BY 06Z.
DESPITE THE LACK OF LTG...SOAKING SHOWERS WILL OCCUR OVERNIGHT
ACROSS MUCH OF THE AREA...BRINGING SOME MUCH NEEDED RAINFALL TO
THE AREA. WITH A LIGHT SOUTHERLY FLOW IN PLACE...MIN TEMPS WON/T
DROP OFF TOO MUCH...WITH MID 50S TO LOW 60S ACROSS THE REGION.
RAINFALL AMOUNTS OVERNIGHT IN COORDINATION WITH THE NERFC LOOK TO
RANGE FROM ABOUT A QUARTER OF AN INCH FOR SE AREAS TO OVER A HALF
INCH ACROSS THE ADIRONDACKS.
ON SATURDAY...THE SFC FRONTAL BOUNDARY ASSOCIATED WITH THE UPPER
TROUGH WILL SLOWLY MOVE ACROSS OUR REGION. WIDESPREAD SHOWERS LOOK
TO OCCUR THROUGH THE MORNING HOURS...AND BEGIN TO TAPER OFF WITH
THE PASSAGE OF THE BOUNDARY DURING THE AFTN. THE 18Z NAM12 SHOWS
SOME MEAGER AMOUNTS OF INSTABILITY...MAINLY FOR AREA FROM THE
CAPITAL REGION ON SOUTH...SO WILL MENTION A SLIGHT CHC FOR SOME
THUNDER AS WELL. AN ADDITIONAL QUARTER TO HALF INCH OF RAINFALL IS
POSSIBLE THROUGH THE DAY ON SATURDAY. DESPITE THE PRECIP AND
CLOUDS...MAX TEMPS WILL BE ABOVE NORMAL...WITH 60S TO NEAR 70 IN
MOST AREAS.
&&
.SHORT TERM /SATURDAY NIGHT THROUGH SUNDAY NIGHT/...
A UPPER LEVEL SHORT WAVE OVER THE UPPER GREAT LAKES WILL BE MOVING
SOUTHEAST INTO WESTERN NEW YORK AND WILL HELP MOVE THE FRONT ALONG
TO THE EAST OUT OF THE REGION AS WE PROGRESS AFTER 00Z SUNDAY. MODEL
ENSEMBLE MEMBERS SHOW BETWEEN 2 AND AS MUCH AS 3 S.D. ANOMALIES
BELOW NORMAL FOR 500 HPA HEIGHT WITH THIS INCOMING SHORTWAVE AS IT
MOVES SOUTHEAST OUT OF CANADA. COOLER TEMPERATURES WILL FOLLOW AS WE
GO INTO THE SECOND HALF OF THE WEEKEND. T850 TEMPS BY SUNDAY WILL
RANGE BETWEEN -3C TO -5C AND T925 WILL HOVER AROUND 0C ESPECIALLY
NORTH AND WEST OF THE IMMEDIATE CAPITAL REGION. THEREFORE AS WE GO
THROUGH SUNDAY EVENING AS WE GET A WEST TO NORTHWEST FLOW OFF THE
LAKE ONTARIO...AN ISOLATED CHANCE OF A LAKE ENHANCED SNOW SHOWERS
FOR THE HIGHEST TERRAIN IN THE ADIRONDACKS SUNDAY NIGHT IS POSSIBLE.
HIGH TEMPS ON SUNDAY WILL BE COOLER RANGING FROM UPPER 50S IN HIGH
TERRAIN TO MID 60S AROUND THE IMMEDIATE CAPITAL REGION TO AROUND 70S
IN THE MID HUDSON VALLEY. SUNDAY NIGHT LOW TEMPERATURES WILL RANGE
FROM THE UPPER 20S IN THE HIGH TERRAIN OF THE ADIRONDACKS TO LOW TO
MID 30S ACROSS VALLEY LOCATIONS.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
ON MONDAY...A STRONG UPPER LEVEL TROUGH WILL BE MOVING ACROSS THE
REGION. THE COLD POOL ASSOCIATED WITH THIS TROUGH /500 HPA TEMPS OF
AROUND -30 DEGREES C/ MAY ALLOW FOR SOME INSTABILITY SHOWERS DURING
THE DAY...ESP FOR AREAS NORTH AND WEST OF THE CAPITAL REGION. ITS
EVEN POSSIBLE THAT SOME OF THE HIGHEST TERRAIN OF THE ADIRONDACKS
COULD SEE SOME WET SNOW FLAKES MIXING IN DURING THE EARLY TO MID
MORNING HOURS. MAX TEMPS WILL BE HELD BELOW NORMAL WITH UPPER 50S
TO NEAR 60 IN VALLEY AREAS...AND 40S TO LOW 50S FOR THE HIGH TERRAIN.
THE THREAT FOR SHOWERS SHOULD END ON MONDAY NIGHT AS THE UPPER
TROUGH BEGINS TO MOVE AWAY. HIGH PRESSURE WILL BUILD INTO THE MID
ATLANTIC...WHICH SHOULD ALLOW FOR CLEARING SKIES AND LIGHTER WINDS
ACROSS OUR AREA. THIS WILL SET THE STAGE FOR ANOTHER CHILLY NIGHT
FOR MONDAY NIGHT WITH GOOD RADIATIONAL COOLING. SOME FROST/FREEZE
ISSUES MAY CROP UP /NO PUN INTENDED/ FOR THOSE PORTIONS OF THE
REGION WHERE THE GROWING SEASON HAS ALREADY BEGUN...WITH MIN TEMPS
RANGING FROM THE MID 20S TO MID 30S ACROSS THE REGION.
HIGH PRESSURE AND WEAK RIDGING ALOFT SHOULD ALLOW FOR DRY WEATHER
FOR TUESDAY INTO TUESDAY NIGHT. TEMPS WILL START TO MODERATE FOR
TUESDAY...ALTHOUGH IT STILL WILL BE BELOW NORMAL WITH MAX TEMPS IN
THE MID 50S TO MID 60S...AND MIN TEMPS RANGING FROM THE UPPER 20S TO
UPPER 30S.
A WARM FRONT WILL MOVE ACROSS THE REGION AT SOME POINT BETWEEN WED
AND THURSDAY. THE MODELS ARE NOT IN TOTAL AGREEMENT WHEN THIS WILL
OCCUR. WITH THE PASSAGE OF THE WARM FRONT...THERE MAY BE SOME LIGHT
RAIN OR RAIN SHOWERS...ALONG WITH WARMING TEMPS ALOFT. FOR NOW...WE
WILL PLACE THE HIGHEST POPS FOR WED NIGHT INTO THURSDAY. MAX TEMPS
SHOULD WARM TO NEAR 70 FOR WED...AND LOWER TO MID 70S FOR THURSDAY.
THE MODELS CONTINUE TO DISAGREE RIGHT INTO FRIDAY AS WELL...WITH THE
ECMWF KEEPING OUR REGION IN THE WARM SECTOR...WHILE THE GFS ALLOWS A
SHORTWAVE TROUGH TO MOVE A COLD FRONT ACROSS OUR AREA. FOR
NOW...WILL FAVOR THE WARMER ECMWF SOLUTION...AND WILL ALLOW SLIGHT
TO CHC POPS FOR RAIN SHOWERS FOR FRIDAY WITH MAX TEMPS IN THE 70S.
&&
.AVIATION /02Z SATURDAY THROUGH WEDNESDAY/...
VFR CONDITIONS ARE CURRENTLY IN PLACE AT ALL TERMINALS WITH JUST A
FEW ISOLD RAIN SHOWERS AROUND. THESE VFR CONDITIONS LOOK TO
CONTINUE FOR THE NEXT FEW HOURS. HOWEVER...A COMPLEX OF
SHOWERS...CURRENTLY ACROSS WESTERN AND CENTRAL NY...WILL MOVE
ACROSS THE REGION OVERNIGHT...MAINLY AFTER MIDNIGHT. THIS WILL
ALLOW FOR WIDESPREAD MVFR CONDITIONS FOR BOTH VSBYS/CIGS. A PERIOD
OF IFR CONDITIONS IS POSSIBLE FOR MOST SITES BY THE LATE NIGHT
HOURS AND INTO SATURDAY MORNING DUE TO PERSISTENT LIGHT TO
MODERATE RAINFALL. AN ISOLD RUMBLE OF THUNDER IS POSSIBLE FOR
SOUTHERN AREAS...BUT COVERAGE LOOKS TO SPARSE TO INCLUDE IN THE
TAF AT THIS TIME. AS THE RAINFALL LIGHTENS UP LATE SAT
MORNING/EARLY SAT AFTN...THERE WILL BE SOME IMPROVEMENT BACK TO
MVFR. HOWEVER...THESE MVFR CONDITIONS LOOK TO LINGER THROUGH THE
REMAINDER OF THE DAY AT KPOU/KPSF...ALTHOUGH SOME IMPROVEMENT TO
VFR IS POSSIBLE BY LATE SAT AFTN AT KALB/KGFL.
SOUTHERLY WINDS WILL INCREASE OVERNIGHT TO 6-12 KTS...WITH THE
HIGHEST SPEEDS AT KALB. WINDS WILL SWITCH TO A WESTERLY DIRECTION
WITH THE PASSAGE OF A COLD FRONT BY THE EARLY AFTN ON SATURDAY.
OUTLOOK...
SAT NIGHT...VFR/MVFR. CHC -SHRA
SUN...VFR. BREEZY.
MON...VFR. CHC -SHRA KGFL AND SLIGHT CHC KALB AND KPSF.
TUE-WED...VFR. NO SIG WX.
&&
.FIRE WEATHER...
WITH A FRONTAL BOUNDARY MOVING INTO SATURDAY...AN ABUNDANT OF
MOISTURE ALONG WITH LIKELY CHANCES OF RAIN. RAINFALL AMOUNTS OF A
HALF OF AN INCH UP TO AN INCH ARE EXPECTED. DRY WEATHER IS EXPECTED
FOR SUNDAY WITH MINIMUM RH IN THE MID 20S TO LOWER 30S.
&&
.HYDROLOGY...
WIDESPREAD SHOWERS TONIGHT INTO SATURDAY. AN ISOLATED THUNDERSTORM
WILL MOVE INTO THE REGION SATURDAY AFTERNOON ESPECIALLY SOUTH AND
EAST OF THE IMMEDIATE CAPITAL REGION. MOST AREAS WILL SEE 0.50 TO
AN INCH WITH LOCAL AMOUNTS UP TO 2 INCHES POSSIBLE IN A
THUNDERSTORM.
WITH TREES LARGELY LEAFED OUT...MUCH OF THIS SHOULD BE ABSORBED...OR
RESULT IN ONLY WITHIN BANK RISES AS RIVER FLOWS ARE CURRENTLY BELOW
NORMAL.
DRIER WEATHER WILL RETURN SUNDAY INTO EARLY NEXT WEEK.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED
AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE
ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...FRUGIS
NEAR TERM...FRUGIS
SHORT TERM...LFM
LONG TERM...FRUGIS
AVIATION...FRUGIS
FIRE WEATHER...LFM
HYDROLOGY...LFM
AREA FORECAST DISCUSSION
NWS ALBANY NY
722 PM EDT FRI MAY 10 2013
.SYNOPSIS...
A SLOW MOVING FRONTAL SYSTEM WILL APPROACH THE REGION
TONIGHT...ALLOWING FOR WIDESPREAD SHOWERS ALONG WITH MILD
TEMPERATURES. SHOWERS AND ISOLATED THUNDERSTORMS WILL CONTINUE
THROUGH THE DAY ON SATURDAY AS THE STORM/S COLD FRONT MOVES ACROSS
THE AREA. DRIER AND SOMEWHAT COOLER WEATHER WILL RETURN FOR MOTHER/S
DAY.
&&
.NEAR TERM /THROUGH SATURDAY/...
AS OF 722 PM EDT...WIDESPREAD CONVECTION ACROSS WESTERN NY WHICH
DEVELOPED THANKS TO A DEEPENING UPSTREAM UPPER TROUGH IS MOVING
E-NE TOWARDS CENTRAL NY. ALTHOUGH THERE WERE NUMEROUS SVR WARNINGS
AND SEVERAL REPORTS OF LARGE HAIL/WIND DAMAGE ACROSS WFO BUF/S
AREA...THIS CONVECTION IS BEGINNING TO SHOW SIGNS OF WEAKENING
THANKS TO THE LOSS OF DAYTIME HEATING. THE CURRENT KENX RADAR
SHOWS IT FAIRLY QUIET ACROSS OUR AREA...WHICH JUST ISOLD LIGHT
RAIN SHOWERS ACROSS THE ADIRONDACKS AND MID HUDSON VALLEY. FOR THE
NEXT FEW HOURS...IT LOOKS FAIRLY QUIET UNTIL THE ACTIVITY OVER
CENTRAL NY MAKES IT INTO OUR CWA.
THE LATEST 21Z 3KM HRRR SHOWS THE UPSTREAM CONVECTION CONTINUING
TO WEAKEN AS IT HEADS TOWARDS OUR REGION. STILL...SOME SOAKING
SHOWERS WILL OCCUR OVERNIGHT /MAINLY FROM ABOUT MIDNIGHT ONWARD/
ACROSS MUCH OF THE AREA...BRINGING SOME MUCH NEEDED RAINFALL TO
THE AREA. WITH A LIGHT SOUTHERLY FLOW IN PLACE...MIN TEMPS WON/T
DROP OFF TOO MUCH...WITH MID 50S TO LOW 60S ACROSS THE REGION.
RAINFALL AMOUNTS OVERNIGHT IN COORDINATION WITH THE NERFC LOOK TO
RANGE FROM ABOUT A QUARTER OF AN INCH FOR SE AREAS TO OVER A HALF
INCH ACROSS THE ADIRONDACKS.
ON SATURDAY...THE SFC FRONTAL BOUNDARY ASSOCIATED WITH THE UPPER
TROUGH WILL SLOWLY MOVE ACROSS OUR REGION. WIDESPREAD SHOWERS LOOK
TO OCCUR THROUGH THE MORNING HOURS...AND BEGIN TO TAPER OFF WITH
THE PASSAGE OF THE BOUNDARY DURING THE AFTN. THE 18Z NAM12 SHOWS
SOME MEAGER AMOUNTS OF INSTABILITY...MAINLY FOR AREA FROM THE
CAPITAL REGION ON SOUTH...SO WILL MENTION A SLIGHT CHC FOR SOME
THUNDER AS WELL. AN ADDITIONAL QUARTER TO HALF INCH OF RAINFALL IS
POSSIBLE THROUGH THE DAY ON SATURDAY. DESPITE THE PRECIP AND
CLOUDS...MAX TEMPS WILL BE ABOVE NORMAL...WITH 60S TO NEAR 70 IN
MOST AREAS.
&&
.SHORT TERM /SATURDAY NIGHT THROUGH SUNDAY NIGHT/...
A UPPER LEVEL SHORT WAVE OVER THE UPPER GREAT LAKES WILL BE MOVING
SOUTHEAST INTO WESTERN NEW YORK AND WILL HELP MOVE THE FRONT ALONG
TO THE EAST OUT OF THE REGION AS WE PROGRESS AFTER 00Z SUNDAY. MODEL
ENSEMBLE MEMBERS SHOW BETWEEN 2 AND AS MUCH AS 3 S.D. ANOMALIES
BELOW NORMAL FOR 500 HPA HEIGHT WITH THIS INCOMING SHORTWAVE AS IT
MOVES SOUTHEAST OUT OF CANADA. COOLER TEMPERATURES WILL FOLLOW AS WE
GO INTO THE SECOND HALF OF THE WEEKEND. T850 TEMPS BY SUNDAY WILL
RANGE BETWEEN -3C TO -5C AND T925 WILL HOVER AROUND 0C ESPECIALLY
NORTH AND WEST OF THE IMMEDIATE CAPITAL REGION. THEREFORE AS WE GO
THROUGH SUNDAY EVENING AS WE GET A WEST TO NORTHWEST FLOW OFF THE
LAKE ONTARIO...AN ISOLATED CHANCE OF A LAKE ENHANCED SNOW SHOWERS
FOR THE HIGHEST TERRAIN IN THE ADIRONDACKS SUNDAY NIGHT IS POSSIBLE.
HIGH TEMPS ON SUNDAY WILL BE COOLER RANGING FROM UPPER 50S IN HIGH
TERRAIN TO MID 60S AROUND THE IMMEDIATE CAPITAL REGION TO AROUND 70S
IN THE MID HUDSON VALLEY. SUNDAY NIGHT LOW TEMPERATURES WILL RANGE
FROM THE UPPER 20S IN THE HIGH TERRAIN OF THE ADIRONDACKS TO LOW TO
MID 30S ACROSS VALLEY LOCATIONS.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
ON MONDAY...A STRONG UPPER LEVEL TROUGH WILL BE MOVING ACROSS THE
REGION. THE COLD POOL ASSOCIATED WITH THIS TROUGH /500 HPA TEMPS OF
AROUND -30 DEGREES C/ MAY ALLOW FOR SOME INSTABILITY SHOWERS DURING
THE DAY...ESP FOR AREAS NORTH AND WEST OF THE CAPITAL REGION. ITS
EVEN POSSIBLE THAT SOME OF THE HIGHEST TERRAIN OF THE ADIRONDACKS
COULD SEE SOME WET SNOW FLAKES MIXING IN DURING THE EARLY TO MID
MORNING HOURS. MAX TEMPS WILL BE HELD BELOW NORMAL WITH UPPER 50S
TO NEAR 60 IN VALLEY AREAS...AND 40S TO LOW 50S FOR THE HIGH TERRAIN.
THE THREAT FOR SHOWERS SHOULD END ON MONDAY NIGHT AS THE UPPER
TROUGH BEGINS TO MOVE AWAY. HIGH PRESSURE WILL BUILD INTO THE MID
ATLANTIC...WHICH SHOULD ALLOW FOR CLEARING SKIES AND LIGHTER WINDS
ACROSS OUR AREA. THIS WILL SET THE STAGE FOR ANOTHER CHILLY NIGHT
FOR MONDAY NIGHT WITH GOOD RADIATIONAL COOLING. SOME FROST/FREEZE
ISSUES MAY CROP UP /NO PUN INTENDED/ FOR THOSE PORTIONS OF THE
REGION WHERE THE GROWING SEASON HAS ALREADY BEGUN...WITH MIN TEMPS
RANGING FROM THE MID 20S TO MID 30S ACROSS THE REGION.
HIGH PRESSURE AND WEAK RIDGING ALOFT SHOULD ALLOW FOR DRY WEATHER
FOR TUESDAY INTO TUESDAY NIGHT. TEMPS WILL START TO MODERATE FOR
TUESDAY...ALTHOUGH IT STILL WILL BE BELOW NORMAL WITH MAX TEMPS IN
THE MID 50S TO MID 60S...AND MIN TEMPS RANGING FROM THE UPPER 20S TO
UPPER 30S.
A WARM FRONT WILL MOVE ACROSS THE REGION AT SOME POINT BETWEEN WED
AND THURSDAY. THE MODELS ARE NOT IN TOTAL AGREEMENT WHEN THIS WILL
OCCUR. WITH THE PASSAGE OF THE WARM FRONT...THERE MAY BE SOME LIGHT
RAIN OR RAIN SHOWERS...ALONG WITH WARMING TEMPS ALOFT. FOR NOW...WE
WILL PLACE THE HIGHEST POPS FOR WED NIGHT INTO THURSDAY. MAX TEMPS
SHOULD WARM TO NEAR 70 FOR WED...AND LOWER TO MID 70S FOR THURSDAY.
THE MODELS CONTINUE TO DISAGREE RIGHT INTO FRIDAY AS WELL...WITH THE
ECMWF KEEPING OUR REGION IN THE WARM SECTOR...WHILE THE GFS ALLOWS A
SHORTWAVE TROUGH TO MOVE A COLD FRONT ACROSS OUR AREA. FOR
NOW...WILL FAVOR THE WARMER ECMWF SOLUTION...AND WILL ALLOW SLIGHT
TO CHC POPS FOR RAIN SHOWERS FOR FRIDAY WITH MAX TEMPS IN THE 70S.
&&
.AVIATION /00Z SATURDAY THROUGH WEDNESDAY/...
VFR CONDITIONS ARE CURRENTLY IN PLACE AT ALL TERMINALS WITH JUST A
FEW ISOLD RAIN SHOWERS AROUND. THESE VFR CONDITIONS LOOK TO
CONTINUE FOR THE NEXT FEW HOURS. HOWEVER...A COMPLEX OF
SHOWERS...CURRENTLY ACROSS WESTERN AND CENTRAL NY...WILL MOVE
ACROSS THE REGION OVERNIGHT...MAINLY AFTER MIDNIGHT. THIS WILL
ALLOW FOR WIDESPREAD MVFR CONDITIONS FOR BOTH VSBYS/CIGS. A PERIOD
OF IFR CONDITIONS IS POSSIBLE FOR MOST SITES BY THE LATE NIGHT
HOURS AND INTO SATURDAY MORNING DUE TO PERSISTENT LIGHT TO
MODERATE RAINFALL. AN ISOLD RUMBLE OF THUNDER IS POSSIBLE FOR
SOUTHERN AREAS...BUT COVERAGE LOOKS TO SPARSE TO INCLUDE IN THE
TAF AT THIS TIME. AS THE RAINFALL LIGHTENS UP LATE SAT
MORNING/EARLY SAT AFTN...THERE WILL BE SOME IMPROVEMENT BACK TO
MVFR. HOWEVER...THESE MVFR CONDITIONS LOOK TO LINGER THROUGH THE
REMAINDER OF THE DAY AT KPOU/KPSF...ALTHOUGH SOME IMPROVEMENT TO
VFR IS POSSIBLE BY LATE SAT AFTN AT KALB/KGFL.
SOUTHERLY WINDS WILL INCREASE OVERNIGHT TO 6-12 KTS...WITH THE
HIGHEST SPEEDS AT KALB. WINDS WILL SWITCH TO A WESTERLY DIRECTION
WITH THE PASSAGE OF A COLD FRONT BY THE EARLY AFTN ON SATURDAY.
OUTLOOK...
SAT NIGHT...VFR/MVFR. CHC -SHRA
SUN...VFR. BREEZY.
MON...VFR. CHC -SHRA KGFL AND SLIGHT CHC KALB AND KPSF.
TUE-WED...VFR. NO SIG WX.
&&
.FIRE WEATHER...
WITH A FRONTAL BOUNDARY MOVING INTO SATURDAY...AN ABUNDANT OF
MOISTURE ALONG WITH LIKELY CHANCES OF RAIN. RAINFALL AMOUNTS OF A
HALF OF AN INCH UP TO AN INCH ARE EXPECTED. DRY WEATHER IS EXPECTED
FOR SUNDAY WITH MINIMUM RH IN THE MID 20S TO LOWER 30S.
&&
.HYDROLOGY...
WIDESPREAD SHOWERS TONIGHT INTO SATURDAY. AN ISOLATED THUNDERSTORM
WILL MOVE INTO THE REGION SATURDAY AFTERNOON ESPECIALLY SOUTH AND
EAST OF THE IMMEDIATE CAPITAL REGION. MOST AREAS WILL SEE 0.50 TO
AN INCH WITH LOCAL AMOUNTS UP TO 2 INCHES POSSIBLE IN A
THUNDERSTORM.
WITH TREES LARGELY LEAFED OUT...MUCH OF THIS SHOULD BE ABSORBED...OR
RESULT IN ONLY WITHIN BANK RISES AS RIVER FLOWS ARE CURRENTLY BELOW
NORMAL.
DRIER WEATHER WILL RETURN SUNDAY INTO EARLY NEXT WEEK.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED
AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE
ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...FRUGIS
NEAR TERM...FRUGIS
SHORT TERM...LFM
LONG TERM...FRUGIS
AVIATION...FRUGIS
FIRE WEATHER...LFM
HYDROLOGY...LFM
AREA FORECAST DISCUSSION
NWS NEW YORK NY
151 AM EDT THU MAY 9 2013
.SYNOPSIS...
WEAK LOW PRESSURE OVER THE MID ATLANTIC STATES WILL TRACK
NORTHEAST AND ACROSS THE AREA ON THURSDAY. A SLOW MOVING COLD
FRONT WILL APPROACH FROM THE WEST FRIDAY AND FRIDAY NIGHT AND
EVENTUALLY PASS EAST SATURDAY NIGHT INTO SUNDAY MORNING. HIGH
PRESSURE THEN RETURNS EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
ISSUED A FOG ADVY FOR ERN LI AND SERN CT BASED ON OBS AND STLT.
WIDESPREAD VSBY 1/4 MILE OR LESS...ESPECIALLY THE TWIN FORKS.
ORGANIZED SHOWERS REMAIN OVER CNTRL NEW ENGLAND AS OF MIDNIGHT.
HRRR IS PERFORMING WELL AS KEEPS THE AREA DRY UNTIL 08-09Z WHEN
A SHORTWAVE/VORT MAX ASSOCIATED WITH UPPER LOW MOVES TOWARDS THE
REGION. SHOWERS ASSOCIATED WITH THIS FEATURE ARE CURRENTLY OVER
THE DELMARVA PENINSULA AND ETA INTO THE SW PORTION OF THE AREA IS
CURRENTLY TIMED TO BE SLIGHTLY EARLIER (06-08Z) THAN THE HRRR IS
INDICATING. THEREFORE...WILL LEAVE INCREASING POPS AFTER 04Z AS
SCT SHOWERS MAY BEGIN TO DEVELOP AHEAD OF THE MAIN AREA. ALSO
REMOVED THUNDER FROM THE FORECAST TONIGHT WITH ONLY VERY WEAK
INSTABILITY EXPECTED TO BE PRESENT ALOFT.
THE ESE FLOW WILL VEER TO A MORE SOUTHERLY FLOW OVERNIGHT AS THE
OCCLUDED FRONT LIFTS NORTH OF THE AREA.
LOWS WILL RANGE FROM THE LOWER TO UPPER 50S. STAYED CLOSE TO MOS
GUIDANCE.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH 6 PM FRIDAY/...
THE UPPER LOW TRACKS ACROSS THE AREA ON THU WITH STEEPENING LAPSE
RATES AND PLENTY OF INSTABILITY CLOUDS AND SHOWERS. THE BEST CHANCE
LOOKS TO BE IN THE MORNING WITH THE BEST LIFT AND DEEPEST
MOISTURE. RAINFALL AMOUNTS ARE EXPECTED TO BE LESS THAN ONE-
QUARTER INCH...HOWEVER ISOLATED HIGHER AMOUNTS ARE POSSIBLE WITH
ANY THUNDERSTORMS. THIS ACTIVITY SHOULD NOT BE AS ORGANIZED AS
THE CONVECTIVE BANDS THAT WENT THROUGH THE AREA ON WED.
HIGHS WILL TOP OUT IN THE LOWER 60S AT THE COAST...TO THE LOWER
70S NORTH AND WEST OF NYC. THIS IS CLOSE TO NORMAL. USED A BLEND
OF THE MOS GUIDANCE.
&&
.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
WEAK DEEP-LAYERED RIDGING SHOULD KEEP US DRY FOR MOST OF THE DAY ON
FRIDAY...HOWEVER THERE COULD BE A LATE DAY THUNDERSTORM FROM AROUND
THE CITY AND POINTS WEST. BASED ON 850MB TEMPS...WENT CLOSER TO NAM
MOS HIGH TEMPERATURES...BUT LOWERED THEM BY A FEW DEGREES ALONG THE
SOUTH FACING SHORES.
A COLD FRONT SLOWLY APPROACHES FRIDAY NIGHT WITH A CHANCE OF A
SHOWER OR TSTM...HOWEVER SHOWERS AND POSSIBLE TSTMS LOOK TO
BE MOST LIKELY DURING SATURDAY AND SATURDAY NIGHT WITH THE FRONT
ENTERING THE AREA. BY DAYBREAK ON SUNDAY...THE FRONT IS MOST LIKELY
EAST OF THE CITY...SO JUST A LINGERING SHOWER POSSIBLE SUNDAY
MORNING. HIGH PRESSURE THEN BUILDS IN BEHIND THE FRONT SUNDAY
AFTERNOON WITH CLEARING SKIES. HIGHS GENERALLY 70-75 ON SATURDAY AND
65-70 ON SUNDAY.
AN UPPER TROUGH SHIFTS INTO THE REGION ON MONDAY/MONDAY NIGHT.
PROBABLY JUST SOME DIURNAL CU BUILDUP...SO WILL KEEP THE FORECAST
DRY FOR NOW. HIGH TEMPS COLDER THAN NORMAL. THE TROUGH SHIFTS EAST
ON TUESDAY WITH MODERATING TEMPERATURES. WILL GO WITH A DRY FORECAST
ON WEDNESDAY FOR NOW...BUT MODELS DEPICT SOME MOISTURE SPILLING OVER
AN UPPER RIDGE TO THE WEST. MAY NEED TO EVENTUALLY INCLUDE CHANCES OF
SHOWERS FOR THIS PERIOD.
&&
.AVIATION /06Z THURSDAY THROUGH MONDAY/...
SLOW MOVING LOW PRESSURE WILL MOVE THROUGH THE AREA THROUGH TODAY
WITH AN ASSOCIATED FRONTAL BOUNDARY MOVING THROUGH OVERNIGHT.
CURRENTLY VFR ACROSS NYC TERMINALS. LOW CONFIDENCE IN DURATION OF
IFR/MVFR CIGS EARLY THIS MORNING. STRATUS AND FOG HAS DEVELOPED
ACROSS LONG ISLAND AND COASTAL CONNECTICUT WITH IFR/LIFR CONDS.
CURRENTLY KISP IS VFR...BUT STILL EXPECT CIGS TO FLUCTUATE BETWEEN
IFR/LIFR. AMENDMENTS ARE LIKELY.
AN AREA OF RAIN IS EXPECTED TO MOVE OVER NYC TERMINALS AROUND 09Z
AND THEN ELSEWHERE LATER THIS MORNING. THIS RAIN COULD ALSO
PREVENT CIGS ACROSS NYC FROM FALLING BELOW MVFR. AS THE RAIN MOVES
OVER LONG ISLAND AND COASTAL CONNECTICUT...CONDITIONS WILL LIKELY
IMPROVE A LITTLE.
LOW CONFIDENCE IN CIGS AFTER 12Z. PERIODS OF RAIN ARE LIKELY WITH
AN ISOLATED THUNDERSTORM ALSO POSSIBLE TODAY. AS THE LOW MOVES TO
THE NORTH OF THE AREA LATE IN THE FORECAST PERIOD...WINDS WILL
BECOME LIGHT FROM THE SOUTH AND SOUTHWEST.
.OUTLOOK FOR 06Z FRIDAY THROUGH MONDAY...
.TONIGHT...IMPROVING CONDITIONS WITH SHOWERS ENDING.
.FRIDAY...CHANCE OF BRIEF MVFR OR LOWER CONDS IN ANY SCT SHOWERS IN
THE AFTERNOON. AN ISOLD TSTM POSSIBLE.
.FRIDAY NIGHT-SUNDAY MORNING...MVFR OR LOWER CONDS LIKELY IN ANY
SHOWERS... MAINLY THROUGH SUNDAY MORNING. AN ISOLD TSTM POSSIBLE SAT
AFTERNOON/EARLY EVENING
.SUNDAY AFTERNOON-MONDAY...VFR.
&&
.MARINE...
ISSUED A FOG ADVY FOR ALL WATERS BUT THE HARBOR WITH DEW POINT
DEPRESSIONS NEAR ZERO. OTHERWISE...SCA FOR HAZARDOUS SEAS REMAINS
IN EFFECT FOR THE OCEAN THROUGH THU. SEAS 4 TO 6 FT IN A SLY SWELL
BEGIN TO GRADUALLY SUBSIDE TO BELOW 5 FT BY THU EVENING. SEAS MAY
LINGER ABOVE 5 FT EAST OF MORICHES INLET FOR A PORTION OF THU
NIGHT.
SEAS REMAIN JUST BELOW SCA CRITERIA ON FRIDAY...THEN BUILD UP TO
5 FT FRIDAY NIGHT ON AN INCREASING SW FLOW. GUSTS ON THE OCEAN
WATERS COULD ALSO REACH 25 KT DURING THE DAYTIME ON SATURDAY AND
SATURDAY EVENING AHEAD OF AN APPROACHING COLD FRONT. WINDS AND
SEAS THEN DIMINISH ON SUNDAY AFTER THE PASSAGE OF THE COLD FRONT
WITH SEAS BELOW 5 FT PERHAPS BY THE END OF THE MORNING. AN
OFFSHORE FLOW THEN MAINTAINS SUB SCA CONDITIONS THROUGH MONDAY.
&&
.HYDROLOGY...
AN ADDITIONAL QUARTER INCH IS POSSIBLE THROUGH THU WITH ISOLATED
HIGHER AMOUNTS WITH ANY THUNDERSTORMS. THIS IN ASSOCIATION WITH
THE UPPER LOW TRACKING ACROSS THE AREA.
ANOTHER HALF INCH TO INCH OF RAINFALL IS POSSIBLE FROM LATE
FRIDAY THROUGH SUNDAY MORNING IN ASSOCIATION WITH A SLOWLY-MOVING
COLD FRONT. LOCALLY HIGHER AMOUNTS ARE POSSIBLE WITH
THUNDERSTORMS.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...DENSE FOG ADVISORY UNTIL 10 AM EDT THIS MORNING FOR CTZ010>012.
NY...DENSE FOG ADVISORY UNTIL 10 AM EDT THIS MORNING FOR NYZ078>081.
NJ...NONE.
MARINE...DENSE FOG ADVISORY UNTIL 10 AM EDT THIS MORNING FOR ANZ330-335-
340-345-350-353-355.
SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 6 PM EDT THIS
EVENING FOR ANZ350-353-355.
&&
$$
SYNOPSIS...JC/DW
NEAR TERM...JMC/DW
SHORT TERM...DW
LONG TERM...JC
AVIATION...DS
MARINE...JMC/JC/DW
HYDROLOGY...JC/DW
AREA FORECAST DISCUSSION
NWS NEW YORK NY
1210 AM EDT THU MAY 9 2013
.SYNOPSIS...
WEAK LOW PRESSURE OVER THE MID ATLANTIC STATES WILL TRACK
NORTHEAST AND ACROSS THE AREA ON THURSDAY. A SLOW MOVING COLD
FRONT WILL APPROACH FROM THE WEST FRIDAY AND FRIDAY NIGHT AND
EVENTUALLY PASS EAST SATURDAY NIGHT INTO SUNDAY MORNING. HIGH
PRESSURE THEN RETURNS EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
ISSUED A FOG ADVY FOR ERN LI AND SERN CT BASED ON OBS AND STLT.
WIDESPREAD VSBY 1/4 MILE OR LESS...ESPECIALLY THE TWIN FORKS.
ORGANIZED SHOWERS REMAIN OVER CNTRL NEW ENGLAND AS OF MIDNIGHT.
HRRR IS PERFORMING WELL AS KEEPS THE AREA DRY UNTIL 08-09Z WHEN
A SHORTWAVE/VORT MAX ASSOCIATED WITH UPPER LOW MOVES TOWARDS THE
REGION. SHOWERS ASSOCIATED WITH THIS FEATURE ARE CURRENTLY OVER
THE DELMARVA PENINSULA AND ETA INTO THE SW PORTION OF THE AREA IS
CURRENTLY TIMED TO BE SLIGHTLY EARLIER (06-08Z) THAN THE HRRR IS
INDICATING. THEREFORE...WILL LEAVE INCREASING POPS AFTER 04Z AS
SCT SHOWERS MAY BEGIN TO DEVELOP AHEAD OF THE MAIN AREA. ALSO
REMOVED THUNDER FROM THE FORECAST TONIGHT WITH ONLY VERY WEAK
INSTABILITY EXPECTED TO BE PRESENT ALOFT.
THE ESE FLOW WILL VEER TO A MORE SOUTHERLY FLOW OVERNIGHT AS THE
OCCLUDED FRONT LIFTS NORTH OF THE AREA.
LOWS WILL RANGE FROM THE LOWER TO UPPER 50S. STAYED CLOSE TO MOS
GUIDANCE.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH 6 PM FRIDAY/...
THE UPPER LOW TRACKS ACROSS THE AREA ON THU WITH STEEPENING LAPSE
RATES AND PLENTY OF INSTABILITY CLOUDS AND SHOWERS. THE BEST CHANCE
LOOKS TO BE IN THE MORNING WITH THE BEST LIFT AND DEEPEST
MOISTURE. RAINFALL AMOUNTS ARE EXPECTED TO BE LESS THAN ONE-
QUARTER INCH...HOWEVER ISOLATED HIGHER AMOUNTS ARE POSSIBLE WITH
ANY THUNDERSTORMS. THIS ACTIVITY SHOULD NOT BE AS ORGANIZED AS
THE CONVECTIVE BANDS THAT WENT THROUGH THE AREA ON WED.
HIGHS WILL TOP OUT IN THE LOWER 60S AT THE COAST...TO THE LOWER
70S NORTH AND WEST OF NYC. THIS IS CLOSE TO NORMAL. USED A BLEND
OF THE MOS GUIDANCE.
&&
.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
WEAK DEEP-LAYERED RIDGING SHOULD KEEP US DRY FOR MOST OF THE DAY ON
FRIDAY...HOWEVER THERE COULD BE A LATE DAY THUNDERSTORM FROM AROUND
THE CITY AND POINTS WEST. BASED ON 850MB TEMPS...WENT CLOSER TO NAM
MOS HIGH TEMPERATURES...BUT LOWERED THEM BY A FEW DEGREES ALONG THE
SOUTH FACING SHORES.
A COLD FRONT SLOWLY APPROACHES FRIDAY NIGHT WITH A CHANCE OF A
SHOWER OR TSTM...HOWEVER SHOWERS AND POSSIBLE TSTMS LOOK TO
BE MOST LIKELY DURING SATURDAY AND SATURDAY NIGHT WITH THE FRONT
ENTERING THE AREA. BY DAYBREAK ON SUNDAY...THE FRONT IS MOST LIKELY
EAST OF THE CITY...SO JUST A LINGERING SHOWER POSSIBLE SUNDAY
MORNING. HIGH PRESSURE THEN BUILDS IN BEHIND THE FRONT SUNDAY
AFTERNOON WITH CLEARING SKIES. HIGHS GENERALLY 70-75 ON SATURDAY AND
65-70 ON SUNDAY.
AN UPPER TROUGH SHIFTS INTO THE REGION ON MONDAY/MONDAY NIGHT.
PROBABLY JUST SOME DIURNAL CU BUILDUP...SO WILL KEEP THE FORECAST
DRY FOR NOW. HIGH TEMPS COLDER THAN NORMAL. THE TROUGH SHIFTS EAST
ON TUESDAY WITH MODERATING TEMPERATURES. WILL GO WITH A DRY FORECAST
ON WEDNESDAY FOR NOW...BUT MODELS DEPICT SOME MOISTURE SPILLING OVER
AN UPPER RIDGE TO THE WEST. MAY NEED TO EVENTUALLY INCLUDE CHANCES OF
SHOWERS FOR THIS PERIOD.
&&
.AVIATION /04Z THURSDAY THROUGH MONDAY/...
SLOW MOVING LOW PRESSURE WILL MOVE THROUGH THE AREA THROUGH THURSDAY
WITH AN ASSOCIATED FRONTAL BOUNDARY MOVING THROUGH OVERNIGHT.
STRATUS AND FOG HAS DEVELOPED ACROSS LONG ISLAND AND COASTAL
CONNECTICUT ...IFR TO LIFR...AND WILL BECOME MORE WIDESPREAD INTO
THE NEW YORK AREA TERMINALS AFTER 06Z. ANOTHER AREA OF RAIN IS
EXPECTED TO ROTATE INTO THE REGION AFTER 08Z AND CONDITIONS WILL
LIKELY IMPROVE A LITTLE.
AS THE LOW MOVES THROUGH THURSDAY PERIODS OF RAIN WILL BE LIKELY
WITH AN ISOLATED THUNDERSTORM ALSO POSSIBLE. AS THE LOW MOVES TO THE
NORTH OF THE AREA LATE IN THE FORECAST PERIOD...WINDS WILL BECOME
LIGHT FROM THE SOUTH AND SOUTHWEST.
.OUTLOOK FOR 00Z FRIDAY THROUGH MONDAY...
.THURSDAY NIGHT...IMPROVING CONDITIONS WITH SHOWERS ENDING.
.FRIDAY...CHANCE OF BRIEF MVFR OR LOWER CONDS IN ANY SCT SHOWERS IN
THE AFTERNOON. AN ISOLD TSTM POSSIBLE.
.FRIDAY NIGHT-SUNDAY MORNING...MVFR OR LOWER CONDS LIKELY IN ANY
SHOWERS... MAINLY THROUGH SUNDAY MORNING. AN ISOLD TSTM POSSIBLE SAT
AFTERNOON/EARLY EVENING
.SUNDAY AFTERNOON-MONDAY...VFR.
&&
.MARINE...
ISSUED A FOG ADVY FOR ALL WATERS BUT THE HARBOR WITH DEW POINT
DEPRESSIONS NEAR ZERO. OTHERWISE...SCA FOR HAZARDOUS SEAS REMAINS
IN EFFECT FOR THE OCEAN THROUGH THU. SEAS 4 TO 6 FT IN A SLY SWELL
BEGIN TO GRADUALLY SUBSIDE TO BELOW 5 FT BY THU EVENING. SEAS MAY
LINGER ABOVE 5 FT EAST OF MORICHES INLET FOR A PORTION OF THU
NIGHT.
SEAS REMAIN JUST BELOW SCA CRITERIA ON FRIDAY...THEN BUILD UP TO
5 FT FRIDAY NIGHT ON AN INCREASING SW FLOW. GUSTS ON THE OCEAN
WATERS COULD ALSO REACH 25 KT DURING THE DAYTIME ON SATURDAY AND
SATURDAY EVENING AHEAD OF AN APPROACHING COLD FRONT. WINDS AND
SEAS THEN DIMINISH ON SUNDAY AFTER THE PASSAGE OF THE COLD FRONT
WITH SEAS BELOW 5 FT PERHAPS BY THE END OF THE MORNING. AN
OFFSHORE FLOW THEN MAINTAINS SUB SCA CONDITIONS THROUGH MONDAY.
&&
.HYDROLOGY...
AN ADDITIONAL QUARTER INCH IS POSSIBLE THROUGH THU WITH ISOLATED
HIGHER AMOUNTS WITH ANY THUNDERSTORMS. THIS IN ASSOCIATION WITH
THE UPPER LOW TRACKING ACROSS THE AREA.
ANOTHER HALF INCH TO INCH OF RAINFALL IS POSSIBLE FROM LATE
FRIDAY THROUGH SUNDAY MORNING IN ASSOCIATION WITH A SLOWLY-MOVING
COLD FRONT. LOCALLY HIGHER AMOUNTS ARE POSSIBLE WITH
THUNDERSTORMS.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...DENSE FOG ADVISORY UNTIL 10 AM EDT THIS MORNING FOR CTZ010>012.
NY...DENSE FOG ADVISORY UNTIL 10 AM EDT THIS MORNING FOR NYZ078>081.
NJ...NONE.
MARINE...DENSE FOG ADVISORY UNTIL 10 AM EDT THIS MORNING FOR ANZ330-335-
340-345-350-353-355.
SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 6 PM EDT THIS
EVENING FOR ANZ350-353-355.
&&
$$
SYNOPSIS...JC/DW
NEAR TERM...JMC/DW
SHORT TERM...DW
LONG TERM...JC
AVIATION...MET
MARINE...JMC/JC/DW
HYDROLOGY...JC/DW
AREA FORECAST DISCUSSION
NWS MIAMI FL
1002 PM EDT FRI MAY 10 2013
.UPDATE...
THE EVENING SURFACE ANALYSIS SHOWED A HIGH PRESSURE RIDGE AXIS
EXTENDING WEST ACROSS THE SRN FLORIDA PENINSULA WITH LIGHT SSE
WINDS. RECENTLY ANIMATED WATER VAPOR LOOP SHOWED AN UPPER RIDGE
EXTENDING NORTHEAST FROM THE FLORIDA STRAITS TO THE WESTERN
ATLANTIC WITH WESTERLY FLOW CONTINUING ACROSS THE LOCAL AREA.
AFTER A FAIRLY ACTIVE AFTERNOON ACROSS MUCH OF THE INTERIOR
LOCATIONS...THE LATEST RADAR LOOP SHOWED A FEW LINGERING MODERATE
TO HEAVY SHOWERS AND STORMS JUST OFF THE PALM BEACH COUNTY COAST.
OVERNIGHT...ANY ACTIVITY SHOULD REMAIN OFF THE EAST COAST OVER THE
WATERS. THE LATEST GRIDDED FORECAST PACKAGE HAS BEEN UPDATED TO
REFLECT THE LATEST OBSERVATIONS AND TRENDS AROUND THE AREA.
&&
.PREV DISCUSSION... /ISSUED 744 PM EDT FRI MAY 10 2013/
UPDATE...
THE WEATHER SHOULD BE DRY TONIGHT INTO SATURDAY MORNING OVER MOST
OF SOUTH FLORIDA TAF SITES...EXCEPT FOR SOME SHOWERS THROUGH 02Z
THIS EVENING AT KBPI TAF SITE. SO HAVE PUT IN VCSH FOR KPBI UNTIL
02Z TONIGHT.
THE WINDS WILL ALSO BECOME LIGHT AND VARIABLE OVER ALL OF THE TAF
SITES TONIGHT BEFORE BECOMING SOUTHEAST AT 5 TO 10 KNOTS ON
SATURDAY MORNING. THE WIND SPEEDS WILL THEN INCREASE TO 10 TO 15
KNOTS WITH GUSTS UP TO 20 KNOTS SATURDAY AFTERNOON FROM THE
SOUTHEAST DIRECTION. THE ONLY EXCEPTION TO THIS IS AT KAPF TAF
SITE WEATHER THE WINDS WILL SWING TO SOUTHWEST DIRECTION AFTER 16Z
SATURDAY...DUE TO THE WEST COAST SEA BREEZE PUSHING INLAND.
AVIATION...54/BNB
PREV DISCUSSION... /ISSUED 158 PM EDT FRI MAY 10 2013/
AVIATION...
VFR CONDITIONS TO PREVAIL AT ALL SITES THROUGH THE NEXT 24 HOURS.
STILL BELIEVE A FEW SHRAS/TSRAS WILL BE POSSIBLE ACROSS MAINLY THE
INTERIOR AND SHOULD NOT AFFECT ANY TAF SITE. LATEST SHORT TERM
GUIDANCE CONTINUES TO SUGGEST THIS AND ALSO PUSHING SOME OF THE
ACTIVITY EASTWARD...POSSIBLY INTERACTING WITH A WEAK SEA
BREEZE...TOWARD KPBI BY 00Z. KEPT ANY PRECIP MENTION OUT OF KPBI
TAF FOR NOW.
PREV DISCUSSION... /ISSUED 1007 AM EDT FRI MAY 10 2013/
UPDATE...
LOOKING TO BE A VERY TRICKY FORECAST THIS MORNING. A WEAK MID
LEVEL TROUGH MOVED ACROSS SOUTH FLORIDA DURING THE LATE AFTERNOON
YESTERDAY AND LAST NIGHT SPARKING CONVECTION PARTICULARLY OFFSHORE
THIS MORNING WHICH THEN BUILT BACK ONSHORE. THAT CONVECTION HAS
NOW WANED AS THE TROUGH CONTINUES TO MOVE EAST. THE INTERESTING
PHENOMENA THIS MORNING IS THE 12Z MFL SOUNDING WHICH SHOWS
SIGNIFICANT WARMING AT 500 MB WITH A DISTINCT INVERSION WHICH IS
NEARLY 5K FEET DEEP. THERE HAS ALSO BEEN SOME DRYING ALOFT WITH
PWAT NOW DOWN TO ABOUT 1.25 INCHES WHICH IS SLIGHTLY BELOW THE
AVERAGE FOR EARLY MAY. SO THE QUESTION IS HOW MUCH OF A FACTOR
WILL THESE TWO CONDITIONS HAVE ON CONVECTION DEVELOPING. THE LOW
LEVELS REMAIN SOMEWHAT UNSTABLE BUT THE OVERALL SOUNDING WOULD
MAKE ME BELIEVE THAT CONVECTION WILL STRUGGLE TO BUILD PAST THE
SHOWER STAGE. HOWEVER, MODEL FORECAST SOUNDINGS SHOW MID LEVEL
MOISTURE RETURN ALTHOUGH IT APPEARS THAT THEY MAY BE SUFFERING
FROM CONVECTIVE FEEDBACK. THE MORNING PROFILE ALSO INDICATES VERY
SLOW STORM MOTION TODAY AT UNDER 5 KNOTS WITH A DRIFT BACK TOWARDS
THE EAST COAST LATE IN THE DAY. THE EARLY MORNING HRRR RUNS
INITIALIZED NEARLY PERFECTLY AND SHOW INTERIOR CONVECTION
DEVELOPING OVER THE INTERIOR BETWEEN 17-18Z AND MOVING LITTLE. IT
WILL BE INTERESTING TO SEE WHAT THE LATER RUNS ILLUSTRATE AFTER IT
INGESTS THE 12Z SOUNDINGS. AT ANY RATE, FEEL THE NEED TO SCALE
BACK TO SLIGHT CHANCE THUNDER OVER THE INTERIOR AND CAN MAKE LATER
ASSESSMENTS AS THINGS MATERIALIZE.
KOB
PREV DISCUSSION... /ISSUED 334 AM EDT FRI MAY 10 2013/
DISCUSSION...
SHOWERS AND THUNDERSTORMS CONTINUED OVER THE ATLANTIC WATERS JUST
EAST OF THE MIAMI-DADE/BROWARD COUNTY BORDER. A FEW SHOWERS AND
THUNDERSTORMS HAVE ALSO DEVELOPED OVER THE METRO AREAS. THESE
SHOWERS AND STORMS ARE EXPECTED TO DIMINISH LATER THIS MORNING AS
A SHORTWAVE EXITS THE REGION.
UPPER RIDGING OVER THE CENTRAL GULF STRETCHING INTO THE LOWER
GREAT LAKES WILL SHIFT EAST TODAY AS A SHORTWAVE TROUGH MOVES FROM
THE CENTRAL PLAINS INTO THE OHIO VALLEY. UPPER HEIGHTS WILL
INCREASE OVER SOUTH FLORIDA...WITH MUCH WARMER AND SOMEWHAT DRIER
AIR ALOFT THAN ON THURSDAY. HOWEVER...LOW LEVEL MOISTURE WILL
REMAIN IN PLACE WITH DEWPOINTS IN THE MID 60S TO AROUND 70...SO
ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS ARE EXPECTED ALONG
THE SEA BREEZE BOUNDARIES ACROSS THE INTERIOR THIS AFTERNOON INTO
THE EARLY EVENING. A LIMITING FACTOR EACH DAY THROUGH THE WEEKEND
WILL BE THE SUBTROPICAL RIDGE OVER THE REGION...WITH WARM AND DRY
AIR FROM 850MB TO 600MB. EASTERLY LOW LEVEL FLOW AND LIGHT WINDS
ALOFT WILL ALLOW FOR SLOW STORM MOTION AND FOR STORMS TO STAY
ACROSS THE INTERIOR AND TOWARDS THE GULF COAST. TEMPERATURES WILL
BE WARM...WITH HIGHS IN THE MID 80S TO LOWER 90S. THE EASTERLY LOW
LEVEL FLOW WILL KEEP OVERNIGHT TEMPS WARM IN THE MID 60S TO THE
MID 70S. A FEW SHOWERS MAY DEVELOP OVERNIGHT ACROSS THE ATLANTIC
WATERS...AND MOVE TOWARDS THE EAST COAST.
ANOTHER UPPER LOW WILL MOVE SOUTHEAST ACROSS THE UPPER GREAT LAKES
ON SATURDAY...WITH THE TROUGH DIGGING INTO THE SOUTHEAST. THIS WILL
ALLOW LOW PRESSURE OVER THE NORTHEAST TO DEEPEN...AND A COLD FRONT
EXTENDING FROM THE LOW WILL PUSH INTO THE SOUTHEAST. DEEPER MOISTURE
WILL BEGIN TO POOL SOUTH OF THIS BOUNDARY OVER SOUTHERN GEORGIA AND
NORTHERN FLORIDA. THE UPPER RIDGE WILL FLATTEN AND PUSH SOUTH...AND
THIS SHOULD ALLOW FOR A LITTLE MORE ACTIVITY ALONG THE SEA BREEZE
BOUNDARIES ACROSS THE INTERIOR. SLOW STORM MOTION IS EXPECTED ONCE
AGAIN.
THE FRONTAL BOUNDARY WILL MOVE INTO NORTH AND CENTRAL FLORIDA ON
SUNDAY...AND SURFACE WINDS WILL SHIFT MORE TO THE SOUTH...WITH
SOUTHWEST TO WESTERLY FLOW ABOVE THE SURFACE. THE DRY AIR WILL
REMAIN IN THE LOW/MID LEVELS...SO POP GUIDANCE REMAINS LOW. THE
SURFACE BOUNDARY WILL MOVE INTO SOUTH FLORIDA OVERNIGHT SUNDAY INTO
MONDAY MORNING...WITH THE MOISTURE BOUNDARY LAGGING BEHIND INTO
CENTRAL FLORIDA. THE SURFACE FRONT WILL MOVE THROUGH THE REGION BY
EARLY AFTERNOON...WITH THE MOISTURE SCOURING OUT FROM NORTH TO SOUTH
BEGINNING MID/LATE AFTERNOON. SO RAIN CHANCES SHOULD BE CONFINED TO
THE SOUTHEASTERN HALF OF THE REGION...IF THE MOISTURE HANGS AROUND
AS THE MODELS INDICATE.
HIGH PRESSURE WILL BUILD INTO THE SOUTHEAST ON TUESDAY...WITH DRIER
AIR AND NORTHEASTERLY FLOW. HIGH PRESSURE WILL THEN REMAIN IN
CONTROL OF THE WEATHER THROUGH THE END OF THE FORECAST PERIOD...WITH
DRY CONDITIONS AND NEAR NORMAL TEMPERATURES. WITH MODERATE
NORTHEASTERLY FLOW TUESDAY AND WEDNESDAY...THERE WILL A HIGHER
THREAT FOR RIP CURRENTS ALONG THE ATLANTIC BEACHES.
MARINE...
LIGHT WINDS WITH SEAS BELOW 4 FT WILL CONTINUE THROUGH
THE WEEKEND. A COLD FRONT WILL MOVE THROUGH THE REGION MONDAY
NIGHT INTO TUESDAY. WINDS WILL INCREASE OUT OF THE
NORTHEAST...WITH DETERIORATING MARINE CONDITIONS.
FIRE WEATHER...
MIN RH`S OVER THE WESTERN INTERIOR WILL BE IN THE
40 OVER THE NEXT COUPLE OF DAYS. THERE`S SOME RH`S NOW IN THE
UPPER 30S OVER THE WESTERN INTERIOR. A FEW TSTORMS WILL BE
POSSIBLE EACH OF THE NEXT FEW DAYS OVER THE INTERIOR.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 74 86 73 86 / 10 20 20 30
FORT LAUDERDALE 76 86 76 86 / 10 20 10 20
MIAMI 76 87 76 88 / 10 10 10 10
NAPLES 71 87 72 86 / 10 10 10 10
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
DISCUSSION/MARINE/FIRE...85/AG
AVIATION/RADAR...54/BNB
AREA FORECAST DISCUSSION
NWS TAMPA BAY RUSKIN FL
920 PM EDT FRI MAY 10 2013
.UPDATE (TONIGHT AND SATURDAY)...
00Z WATER VAPOR AND H4 RAP ANALYSIS SHOWS A RATHER FLAT UPPER LEVEL
PATTERN IN PLACE ACROSS THE FL PENINSULA THIS EVENING. 00Z KTBW
SOUNDING PROFILE SHOWS THAT THE COLUMN HAS MOISTENED SOMEWHAT OVER
THE PAST 24 HOURS...AND THIS ALLOWED THE SEA-BREEZE CONVECTION TO
EXTEND FURTHER NORTH INTO THE CENTRAL PENINSULA COMPARED TO WHAT WAS
OBSERVED ON THURSDAY. FOR THE MOST PART...THE CONVECTION SEEN IN OUR
AREA WAS ACROSS THE SOUTH-CENTRAL ZONES...AND LIKELY A PARTIAL
RESULT OF LAKE OKEECHOBEE BREEZES.
PATTERN WILL BE AMPLIFYING OVER THE EASTERN HALF OF THE NATION
THROUGH THE FIRST HALF OF THE WEEKEND...ALTHOUGH MUCH OF THE
INFLUENCE OF THIS AMPLIFICATION WILL BE TO OUR NORTH THROUGH
SATURDAY.
FOR THE REMAINDER OF THE OVERNIGHT...LAST FEW CONVECTIVE CELLS WELL
INLAND SHOULD DISSIPATE IN THE NEXT HOUR OR 2 WITH THE LOSS OF
DIURNAL HEATING AND DISSIPATING OF THE SEA-BREEZES. CONDITIONS WILL
BE MAINLY DRY AND SEASONABLE THEREAFTER.
SATURDAY WILL BE A WARM AND SUMMER-LIKE DAY WITH HIGH TEMPERATURES
INTO THE UPPER 80S TO LOWER 90S AWAY FROM THE BEACHES. A CONTINUED
INCREASE IN MOISTURE AND THE SLOW APPROACH OF SOME WEAK SYNOPTIC
SUPPORT ALONG THE NORTHERN GULF COAST SHOULD HELP AID AN EVEN
GREATER COVERAGE OF AFTERNOON SHOWERS AND STORMS. BEST CHANCES TO
SEE AN AFTERNOON/EVENING STORM WILL BE ALONG THE NATURE COAST...AND
INLAND TO THE SOUTH OF I-4. ALTHOUGH A BRIEF STORM IS POSSIBLE CLOSE
TO THE COAST DURING THE EARLY AFTERNOON SOUTH OF TAMPA BAY...THE
QUICK INLAND PROGRESS OF THE SEA-BREEZE SHOULD KEEP MOST OF THE
SCATTERED ACTIVITY BY LATER AFTERNOON/EVENING ACROSS
POLK...HARDEE...DESOTO..AND HIGHLAND COUNTIES.
&&
.AVIATION...
HAVE OPTED TO KEEP VFR FOR THE NEXT 24 HOURS. PGD/LAL MAY SEE
LIMITED BR AND LOW STRATUS TOWARD SUNRISE. ONSHORE WINDS BECOME
LIGHT/VARIABLE OVERNIGHT...S-SE IN THE MORNING...THEN SW IN THE
AFTERNOON. THE SW FLOW WILL KEEP AFTERNOON SHRA/TSRA MAINLY INLAND
WITH ONLY LAL EXPECTED TO HAVE VCNTY TSRA.
&&
.MARINE...
HIGH PRESSURE WILL REMAIN THE DOMINANT WEATHER FEATURE THROUGH
SATURDAY. A COLD FRONT WILL APPROACH FROM THE NORTH SATURDAY
NIGHT...THEN MOVE THROUGH THE WATERS FROM NORTHWEST TO SOUTHEAST
SUNDAY AND SUNDAY NIGHT. HIGH PRESSURE WILL BUILD FROM THE NORTH
MONDAY THROUGH THE MIDDLE OF NEXT WEEK. WINDS COULD REACH ADVISORY
CRITERIA BEHIND THE FRONT SUNDAY NIGHT THROUGH MONDAY NIGHT.
OTHERWISE WINDS AND SEAS ARE EXPECTED TO REMAIN BELOW HEADLINE
THRESHOLDS.
&&
.PRELIMINARY POINT TEMPS/POPS...
TPA 71 86 72 84 / 0 20 20 30
FMY 71 90 71 89 / 0 20 10 20
GIF 70 90 70 88 / 10 40 20 40
SRQ 69 83 71 82 / 0 10 20 20
BKV 62 87 65 86 / 10 40 30 50
SPG 73 86 73 84 / 0 20 20 30
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GULF WATERS...NONE.
&&
$$
UPDATE...MROCZKA
AVIATION...RUDE
AREA FORECAST DISCUSSION...UPDATED
NWS MIAMI FL
744 PM EDT FRI MAY 10 2013
.UPDATE...
THE WEATHER SHOULD BE DRY TONIGHT INTO SATURDAY MORNING OVER MOST
OF SOUTH FLORIDA TAF SITES...EXCEPT FOR SOME SHOWERS THROUGH 02Z
THIS EVENING AT KBPI TAF SITE. SO HAVE PUT IN VCSH FOR KPBI UNTIL
02Z TONIGHT.
THE WINDS WILL ALSO BECOME LIGHT AND VARIABLE OVER ALL OF THE TAF
SITES TONIGHT BEFORE BECOMING SOUTHEAST AT 5 TO 10 KNOTS ON
SATURDAY MORNING. THE WIND SPEEDS WILL THEN INCREASE TO 10 TO 15
KNOTS WITH GUSTS UP TO 20 KNOTS SATURDAY AFTERNOON FROM THE
SOUTHEAST DIRECTION. THE ONLY EXCEPTION TO THIS IS AT KAPF TAF
SITE WEATHER THE WINDS WILL SWING TO SOUTHWEST DIRECTION AFTER 16Z
SATURDAY...DUE TO THE WEST COAST SEA BREEZE PUSHING INLAND.
&&
.AVIATION...54/BNB
.PREV DISCUSSION... /ISSUED 158 PM EDT FRI MAY 10 2013/
AVIATION...
VFR CONDITIONS TO PREVAIL AT ALL SITES THROUGH THE NEXT 24 HOURS.
STILL BELIEVE A FEW SHRAS/TSRAS WILL BE POSSIBLE ACROSS MAINLY THE
INTERIOR AND SHOULD NOT AFFECT ANY TAF SITE. LATEST SHORT TERM
GUIDANCE CONTINUES TO SUGGEST THIS AND ALSO PUSHING SOME OF THE
ACTIVITY EASTWARD...POSSIBLY INTERACTING WITH A WEAK SEA
BREEZE...TOWARD KPBI BY 00Z. KEPT ANY PRECIP MENTION OUT OF KPBI
TAF FOR NOW.
PREV DISCUSSION... /ISSUED 1007 AM EDT FRI MAY 10 2013/
UPDATE...
LOOKING TO BE A VERY TRICKY FORECAST THIS MORNING. A WEAK MID
LEVEL TROUGH MOVED ACROSS SOUTH FLORIDA DURING THE LATE AFTERNOON
YESTERDAY AND LAST NIGHT SPARKING CONVECTION PARTICULARLY OFFSHORE
THIS MORNING WHICH THEN BUILT BACK ONSHORE. THAT CONVECTION HAS
NOW WANED AS THE TROUGH CONTINUES TO MOVE EAST. THE INTERESTING
PHENOMENA THIS MORNING IS THE 12Z MFL SOUNDING WHICH SHOWS
SIGNIFICANT WARMING AT 500 MB WITH A DISTINCT INVERSION WHICH IS
NEARLY 5K FEET DEEP. THERE HAS ALSO BEEN SOME DRYING ALOFT WITH
PWAT NOW DOWN TO ABOUT 1.25 INCHES WHICH IS SLIGHTLY BELOW THE
AVERAGE FOR EARLY MAY. SO THE QUESTION IS HOW MUCH OF A FACTOR
WILL THESE TWO CONDITIONS HAVE ON CONVECTION DEVELOPING. THE LOW
LEVELS REMAIN SOMEWHAT UNSTABLE BUT THE OVERALL SOUNDING WOULD
MAKE ME BELIEVE THAT CONVECTION WILL STRUGGLE TO BUILD PAST THE
SHOWER STAGE. HOWEVER, MODEL FORECAST SOUNDINGS SHOW MID LEVEL
MOISTURE RETURN ALTHOUGH IT APPEARS THAT THEY MAY BE SUFFERING
FROM CONVECTIVE FEEDBACK. THE MORNING PROFILE ALSO INDICATES VERY
SLOW STORM MOTION TODAY AT UNDER 5 KNOTS WITH A DRIFT BACK TOWARDS
THE EAST COAST LATE IN THE DAY. THE EARLY MORNING HRRR RUNS
INITIALIZED NEARLY PERFECTLY AND SHOW INTERIOR CONVECTION
DEVELOPING OVER THE INTERIOR BETWEEN 17-18Z AND MOVING LITTLE. IT
WILL BE INTERESTING TO SEE WHAT THE LATER RUNS ILLUSTRATE AFTER IT
INGESTS THE 12Z SOUNDINGS. AT ANY RATE, FEEL THE NEED TO SCALE
BACK TO SLIGHT CHANCE THUNDER OVER THE INTERIOR AND CAN MAKE LATER
ASSESSMENTS AS THINGS MATERIALIZE.
KOB
PREV DISCUSSION... /ISSUED 334 AM EDT FRI MAY 10 2013/
DISCUSSION...
SHOWERS AND THUNDERSTORMS CONTINUED OVER THE ATLANTIC WATERS JUST
EAST OF THE MIAMI-DADE/BROWARD COUNTY BORDER. A FEW SHOWERS AND
THUNDERSTORMS HAVE ALSO DEVELOPED OVER THE METRO AREAS. THESE
SHOWERS AND STORMS ARE EXPECTED TO DIMINISH LATER THIS MORNING AS
A SHORTWAVE EXITS THE REGION.
UPPER RIDGING OVER THE CENTRAL GULF STRETCHING INTO THE LOWER
GREAT LAKES WILL SHIFT EAST TODAY AS A SHORTWAVE TROUGH MOVES FROM
THE CENTRAL PLAINS INTO THE OHIO VALLEY. UPPER HEIGHTS WILL
INCREASE OVER SOUTH FLORIDA...WITH MUCH WARMER AND SOMEWHAT DRIER
AIR ALOFT THAN ON THURSDAY. HOWEVER...LOW LEVEL MOISTURE WILL
REMAIN IN PLACE WITH DEWPOINTS IN THE MID 60S TO AROUND 70...SO
ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS ARE EXPECTED ALONG
THE SEA BREEZE BOUNDARIES ACROSS THE INTERIOR THIS AFTERNOON INTO
THE EARLY EVENING. A LIMITING FACTOR EACH DAY THROUGH THE WEEKEND
WILL BE THE SUBTROPICAL RIDGE OVER THE REGION...WITH WARM AND DRY
AIR FROM 850MB TO 600MB. EASTERLY LOW LEVEL FLOW AND LIGHT WINDS
ALOFT WILL ALLOW FOR SLOW STORM MOTION AND FOR STORMS TO STAY
ACROSS THE INTERIOR AND TOWARDS THE GULF COAST. TEMPERATURES WILL
BE WARM...WITH HIGHS IN THE MID 80S TO LOWER 90S. THE EASTERLY LOW
LEVEL FLOW WILL KEEP OVERNIGHT TEMPS WARM IN THE MID 60S TO THE
MID 70S. A FEW SHOWERS MAY DEVELOP OVERNIGHT ACROSS THE ATLANTIC
WATERS...AND MOVE TOWARDS THE EAST COAST.
ANOTHER UPPER LOW WILL MOVE SOUTHEAST ACROSS THE UPPER GREAT LAKES
ON SATURDAY...WITH THE TROUGH DIGGING INTO THE SOUTHEAST. THIS WILL
ALLOW LOW PRESSURE OVER THE NORTHEAST TO DEEPEN...AND A COLD FRONT
EXTENDING FROM THE LOW WILL PUSH INTO THE SOUTHEAST. DEEPER MOISTURE
WILL BEGIN TO POOL SOUTH OF THIS BOUNDARY OVER SOUTHERN GEORGIA AND
NORTHERN FLORIDA. THE UPPER RIDGE WILL FLATTEN AND PUSH SOUTH...AND
THIS SHOULD ALLOW FOR A LITTLE MORE ACTIVITY ALONG THE SEA BREEZE
BOUNDARIES ACROSS THE INTERIOR. SLOW STORM MOTION IS EXPECTED ONCE
AGAIN.
THE FRONTAL BOUNDARY WILL MOVE INTO NORTH AND CENTRAL FLORIDA ON
SUNDAY...AND SURFACE WINDS WILL SHIFT MORE TO THE SOUTH...WITH
SOUTHWEST TO WESTERLY FLOW ABOVE THE SURFACE. THE DRY AIR WILL
REMAIN IN THE LOW/MID LEVELS...SO POP GUIDANCE REMAINS LOW. THE
SURFACE BOUNDARY WILL MOVE INTO SOUTH FLORIDA OVERNIGHT SUNDAY INTO
MONDAY MORNING...WITH THE MOISTURE BOUNDARY LAGGING BEHIND INTO
CENTRAL FLORIDA. THE SURFACE FRONT WILL MOVE THROUGH THE REGION BY
EARLY AFTERNOON...WITH THE MOISTURE SCOURING OUT FROM NORTH TO SOUTH
BEGINNING MID/LATE AFTERNOON. SO RAIN CHANCES SHOULD BE CONFINED TO
THE SOUTHEASTERN HALF OF THE REGION...IF THE MOISTURE HANGS AROUND
AS THE MODELS INDICATE.
HIGH PRESSURE WILL BUILD INTO THE SOUTHEAST ON TUESDAY...WITH DRIER
AIR AND NORTHEASTERLY FLOW. HIGH PRESSURE WILL THEN REMAIN IN
CONTROL OF THE WEATHER THROUGH THE END OF THE FORECAST PERIOD...WITH
DRY CONDITIONS AND NEAR NORMAL TEMPERATURES. WITH MODERATE
NORTHEASTERLY FLOW TUESDAY AND WEDNESDAY...THERE WILL A HIGHER
THREAT FOR RIP CURRENTS ALONG THE ATLANTIC BEACHES.
MARINE...
LIGHT WINDS WITH SEAS BELOW 4 FT WILL CONTINUE THROUGH
THE WEEKEND. A COLD FRONT WILL MOVE THROUGH THE REGION MONDAY
NIGHT INTO TUESDAY. WINDS WILL INCREASE OUT OF THE
NORTHEAST...WITH DETERIORATING MARINE CONDITIONS.
FIRE WEATHER...
MIN RH`S OVER THE WESTERN INTERIOR WILL BE IN THE
40 OVER THE NEXT COUPLE OF DAYS. THERE`S SOME RH`S NOW IN THE
UPPER 30S OVER THE WESTERN INTERIOR. A FEW TSTORMS WILL BE
POSSIBLE EACH OF THE NEXT FEW DAYS OVER THE INTERIOR.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 74 86 73 86 / 10 20 20 30
FORT LAUDERDALE 76 86 76 86 / 10 20 10 20
MIAMI 76 87 76 88 / 10 10 10 10
NAPLES 71 87 72 86 / 10 10 10 10
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
DISCUSSION/MARINE/FIRE...84/AK
AVIATION/RADAR...54/BNB
AREA FORECAST DISCUSSION
NWS MIAMI FL
224 PM EDT THU MAY 9 2013
...CONTINUED LOW RISK OF ONE OR TWO STRONG-SEVERE TSTORMS SE FL
THROUGH EARLY THIS EVENING...
.DISCUSSION...FORMIDABLE ATLANTIC SEA BREEZE HAS DEVELOPED AND NOW
LIES WEST OF THE I-95 CORRIDOR IN PALM BEACH COUNTY AND ALONG AND
WEST OF THE FLORIDA TURNPIKE IN BROWARD AND MIAMI-DADE COUNTIES.
HUMIDITY IS DEFINITELY ON THE INCREASE SE OF THIS BOUNDARY WITH
DEWPOINTS NOW UP TO 70F AT MIA WITH A HEAT INDEX OF 91F. SO
DEFINITELY HOTTER AND MORE HUMID ACROSS THE EAST COAST METRO AREAS
TODAY. MESOANALYSIS SHOWS SURFACE BASED CAPE NOW REACHING
3500-4000 J/KG ALONG THE SE COAST. LATEST ACARS DATA SHOWS 500 MB
TEMP NOW AROUND -13.5C. HRRR CONTINUES TO INSIST ON CONVECTION
DEVELOPING AND FOCUSING OVER THE RURAL EASTERN INTERIOR. HOWEVER,
IF WE GET BIG STORMS TO DEVELOP, STORM MOTION VECTORS CONTINUE OUT
OF THE W-NW AT AROUND 10 KT, SO WE ANTICIPATE ANY THUNDERSTORMS
WHICH DEVELOP TO TRACK BACK TOWARDS THE ATLANTIC COAST. PEAK
OUTSIDE SHOWS A BUILDING CUMULUS SO IT LOOKS AS THOUGH THINGS WILL
START TO DEVELOP AND HAVE NOT MADE ANY SIGNIFICANT CHANGES TO THE
FORECAST INTO THIS EVENING. A FEW STRONG-SEVERE TSTORMS APPEAR
POSSIBLE GIVEN THE RECORD COLD AIR ALOFT (WHEN COMPARING DATA FROM
THE PAST 25 YEARS).
NO SIGNFICANT CHANGES WERE MADE TO THE FORECAST FOR FRIDAY AND
INTO THE UPCOMING WEEKEND AND BEYOND. MID/UPPER RIDGING GRADUALLY
BUILDS IN FROM THE SW WITH THE VERY COLD AIR ALOFT SHIFTING
NORTHEAST WITH WARMING TEMPS IN THE MID LEVELS. MOISTURE WILL
CONTINUE RATHER LIMITED WITH ACTUALLY FORECAST SOUNDINGS OFF THE
GFS SHOWING SLIGHT DRYING FRI-SAT. ALSO, A MORE SE WIND FLOW
PREDOMINATES AND THIS WILL LEAD TO ANY CONVECTION FOCUSING ACROSS
THE INTERIOR.
GFS CONTINUES TO SHOW A COLD FRONT MOVING ACROSS SOUTH FL LATE MON
INTO EARLY TUESDAY. MOISTURE WILL INCREASE AHEAD OF THIS FRONT
WITH BETTER PROSPECTS FOR SHOWERS AND THUNDERSTORMS MONDAY. DRIER
AND SLIGHTLY COOLER AIR, BUT NOTICEABLE GIVEN LOWERING HUMIDITY ON
AN INCREASINE EASTERLY BREEZE BY THE MIDDLE PART OF NEXT WEEK
BEHIND THE FRONT.
&&
.MARINE...LIGHT WINDS WITH SEAS BELOW 4 FT WILL CONTINUE THROUGH
THE WEEKEND. BEHIND THE COLD FRONT TUESDAY, WINDS WILL INCREASE
WITH WORSENING MARINE CONDITIONS THEN.
&&
.FIRE WEATHER...MIN RH`S OVER THE WESTERN INTERIOR WILL BE IN THE
40 OVER THE NEXT COUPLE OF DAYS. THERE`S SOME RH`S NOW IN THE
UPPER 30S OVER THE WESTERN INTERIOR. A FEW TSTORMS WILL BE
POSSIBLE EACH OF THE NEXT FEW DAYS OVER THE INTERIOR.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 72 85 74 86 / 30 10 - 10
FORT LAUDERDALE 74 86 76 86 / 30 10 10 10
MIAMI 74 87 75 87 / 30 10 10 10
NAPLES 68 89 70 88 / - 10 10 10
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
DISCUSSION/MARINE/FIRE...57/GREGORIA
AVIATION/RADAR...71/JE
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
131 PM EDT THU MAY 9 2013
.SYNOPSIS...
HIGH PRESSURE WILL EXTEND INTO THE REGION THROUGH FRIDAY UNTIL A
COLD FRONT PASSES OVER THE FORECAST AREA LATE THIS WEEKEND. COOLER
HIGH PRESSURE WILL THEN SETTLE OVER THE REGION THROUGH EARLY NEXT
WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
EARLY THIS AFTERNOON...NO CHANGES MADE TO THE FORECAST FOR THIS
UPDATE. PREVIOUS DISCUSSION FOLLOWS BELOW.
LATE THIS MORNING...A CLOSED UPPER LOW OVER THE
NORTHEAST WILL CONTINUE TO PULL AWAY FROM THE AREA TODAY AS
HEIGHTS RISE AND RIDGING BUILDS. SURFACE HIGH PRESSURE CENTERED
OVER THE EASTERN GULF OF MEXICO WILL DOMINATE THE PATTERN TODAY
WITH LIGHT SOUTHWEST FLOW. THE MAIN QUESTION FOR THE AFTERNOON
FORECAST IS THE POTENTIAL FOR ISOLATED SHOWER/THUNDERSTORM
DEVELOPMENT. LOW LEVEL THICKNESS VALUES SUPPORT HIGHS AROUND THE
MID 80S...AND WHEN MODIFYING THE 12Z CHS SOUNDING...THAT WOULD
GENERATE POSITIVE CAPE VALUES. HOWEVER...WITH THE RIDGE BUILDING
ALOFT AND HEIGHTS RISING...MID LEVEL TEMPS ARE PROGGED TO WARM
WHICH IS EXPECTED TO THWART ANY CONVECTIVE DEVELOPMENT. COARSER
RESOLUTION MODELS ARE GENERATING SOME CONVECTION RIGHT ALONG THE
COAST IN THE LATE AFTERNOON...WHILE HIGHER RESOLUTION RUNS FAVOR
THE DRY SIDE. LOOKING THROUGH AFTERNOON RAP SOUNDINGS SHOWS THE
POTENTIAL FOR VERY THIN CAPE...PRIMARILY ACROSS SOUTHEAST SC. WITH
THE WESTERLY FLOW IN PLACE...HAVE DECIDED TO STICK WITH A DRY
FORECAST AND FAVOR THE HIGHER RESOLUTION MODEL RUNS.
OTHERWISE...EXPECT A DECENT GOOD DIURNAL CU FIELD BEGINNING IN THE
EARLY AFTERNOON AND THEN DISSIPATING IN THE EARLY EVENING WITH THE
LOSS OF HEATING.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY/...
TONIGHT...THE AREA WILL REMAIN ALONG THE WESTERN PERIPHERY OF
ATLANTIC HIGH PRESSURE TONIGHT. ANY LINGERING CUMULUS WILL QUICKLY
DISSIPATE WITH THE LOSS OF INSOLATION LEAVING MAINLY CLEAR SKIES.
THERE WILL BE SOME INCREASE IN HIGH-LEVEL MOISTURE EARLY
FRIDAY...BUT THE MOISTURE LOOKS PRETTY THIN AT THIS TIME. A MOSTLY
CLEAR SKY CHARACTER SHOULD WORK. MODEL 925MB WIND FIELDS DO NOT
INCREASE SUBSTANTIALLY OVERNIGHT SO EXPECT THE BOUNDARY LAYER TO
DECOUPLE RATHER QUICKLY THIS EVENING WITH FAIRLY LIGHT WIND FIELDS
PREVAILING...ESPECIALLY INLAND. LOWS WILL BOTTOM OUT IN THE LOWER
60S MOST LOCATIONS WITH MID 60S AT THE COAST. COULD SEE A FEW
UPPER 50S IN A FEW OF THE NORMALLY COOLER SITES SUCH AS ALLENDALE
AND JAMESTOWN.
FRIDAY...QUIET CONDITIONS WILL PERSIST THROUGH EARLY WEEKEND WITH
WEAK HIGH PRESSURE AT THE SFC AND MID LVL RIDGING PEAKING ALOFT.
TEMPS WILL WARM CONSIDERABLY WITH SOUTHERLY FLOW IN PLACE UNDER
MOSTLY SUNNY SKIES. 1000-850 MB THICKNESSES FAVOR HIGH TEMPS IN THE
MID/UPPER 80S FRIDAY AFTERNOON...HIGHEST OVER INLAND AREAS IN
SOUTHEAST GEORGIA. FRIDAY NIGHT LOWS SHOULD REMAIN IN THE LOW/MID
60S AHEAD OF A COLD FRONT ADVANCING TO THE SOUTHEASTERN UNITED
STATES.
SATURDAY AND SUNDAY...CHANCES OF PRECIP WILL BEGIN TO INCREASE FOR
THE SECOND HALF OF THIS WEEKEND AS MID LVL RIDGING SLIDES EAST WHILE
SUBTLE H5 SHORTWAVES EJECT FROM THE SOUTHERN PLAINS TOWARDS THE
SOUTHEASTERN UNITED STATES. SHOWERS AND/OR THUNDERSTORM ACTIVITY
SHOULD INCREASE BY SATURDAY AFTERNOON/EVENING AS ISENTROPIC ASCENT
INCREASES AND BOUNDARY LAYER MOISTURE DEEPENS AHEAD OF A COLD FRONT
ADVANCING TOWARDS THE FORECAST AREA LATE. DESPITE INCREASING CLOUD
COVER...SFC TEMPS SHOULD PEAK IN THE LOW/MID 80S ON SATURDAY. PRECIP
COVERAGE SHOULD EXPAND SATURDAY NIGHT AS PWATS APPROACH 1.50-1.75
INCHES ALONG/AHEAD OF THE COLD FRONT.
AT THIS TIME...PRECIP ACTIVITY LOOKS TO PEAK AS THE COLD FRONT
PUSHES THROUGH THE FORECAST AREA SUNDAY MORNING. GIVEN THE TIME OF
COLD FROPA...THE CHANCE OF STRONGER THUNDERSTORMS WILL REMAIN LOW.
HOWEVER...SOME SHOWERS AND/OR THUNDERSTORMS MAY PRODUCE HEAVY RAIN
BEFORE THE COLD FRONT SHIFTS OFFSHORE. CONDITIONS WILL LIKELY
IMPROVE OVER THE AREA THROUGH SUNDAY EVENING AS HIGH PRESSURE BEGINS
TO BUILD IN BEHIND THE COLD FRONT SHIFTING OFFSHORE. GIVEN THE
AMOUNT OF CLOUD COVER AND SHOWER/THUNDERSTORM ACTIVITY...OVERALL
HIGH TEMPS WILL REMAIN COOLER ON SUNDAY...IN THE UPPER 70S TO AROUND
80.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
A QUIET PERIOD OF WEATHER IS ANTICIPATED NEXT WEEK AS DRY AND COOLER
HIGH PRESSURE BUILDS IN BEHIND A COLD FRONT SHIFTING OVER THE
WESTERN ATLANTIC. MONDAY COULD START OFF BREEZY AS COOLER AIR SHIFTS
SOUTH OVER THE FORECAST AREA INITIALLY. OVERALL TEMPS WILL REMAIN IN
THE LOW/MID 70S MONDAY AND TUESDAY AS THE AREA REMAINS UNDER A
NORTHERLY FLOW. OVERNIGHT LOWS WILL ALSO BE COOL...IN THE UPPER 40S
TO LOWER 50S. TEMPS SHOULD THEN GRADUALLY WARM WEDNESDAY AND
THURSDAY AS SFC HIGH PRESSURE BECOMES CENTERED OVER THE SOUTHEASTERN
UNITED STATES WHILE A DOWNSLOPING WIND COMPONENT DEVELOPS OVER THE
FORECAST AREA. IN GENERAL...OVERALL TEMPS WILL WARM TO AROUND 80 ON
WEDNESDAY AND THEN INTO THE LOWER 80S ON THURSDAY.
&&
.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
VFR THROUGH 18Z FRIDAY.
EXTENDED AVIATION OUTLOOK...LOW CHANCES OF MVFR CIGS/VSBYS WITH
COLD FRONTAL PASSAGE SATURDAY/SUNDAY.
&&
.MARINE...
TODAY AND TONIGHT...THERE ARE NO CONCERNS. A BROAD SOUTHERN FLOW
REGIME WILL PERSIST WITH SPEEDS GENERALLY 10-15 KT AND SEAS 2-4
FT.
FRIDAY THROUGH TUESDAY...MARINE CONDITIONS WILL REMAIN QUIET THROUGH
LATE WEEK AS HIGH PRESSURE REMAINS OVER THE WATERS. IN
GENERAL...WINDS WILL REMAIN AT OR BELOW 15 KTS...HIGHEST ALONG THE
COAST EACH AFTERNOON WITH SEABREEZE CIRCULATIONS. SEAS WILL REMAIN
AT OR BELOW 4 FT...HIGHEST OVER NORTHERN SC WATERS AND OUTER GEORGIA
WATERS. WINDS/SEAS WILL THEN GRADUALLY INCREASE/BUILD LATE WEEKEND
ALONG/AHEAD OF A COLD FRONT PASSING OVER THE WATERS ON SUNDAY.
ALTHOUGH CONDITIONS ARE EXPECTED TO REMAIN BELOW ADVISORY LEVELS
WITH COLD FROPA...COOL HIGH PRESSURE BEHIND THE FRONT SHOULD RESULT
IN WINDS OF 15-20 KTS ALONG WITH SEAS BUILDING TO 4-5 FT ON
MONDAY...HIGHEST OVER WATERS BEYOND 10 NM FROM THE COAST. CONDITIONS
WILL THEN IMPROVE BY TUESDAY AND REMAIN WELL BELOW ADVISORY LEVELS
THROUGH THE MIDDLE OF NEXT WEEK.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...BSH
SHORT TERM...DPB/ST
LONG TERM...DPB
AVIATION...BSH
MARINE...DPB/ST
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
1033 AM EDT THU MAY 9 2013
.SYNOPSIS...
HIGH PRESSURE WILL EXTEND INTO THE REGION THROUGH FRIDAY UNTIL A
COLD FRONT PASSES OVER THE FORECAST AREA LATE THIS WEEKEND. COOLER
HIGH PRESSURE WILL THEN SETTLE OVER THE REGION THROUGH EARLY NEXT
WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
LATE THIS MORNING...A CLOSED UPPER LOW OVER THE NORTHEAST WILL
CONTINUE TO PULL AWAY FROM THE AREA TODAY AS HEIGHTS RISE AND
RIDGING BUILDS. SURFACE HIGH PRESSURE CENTERED OVER THE EASTERN
GULF OF MEXICO WILL DOMINATE THE PATTERN TODAY WITH LIGHT
SOUTHWEST FLOW. THE MAIN QUESTION FOR THE AFTERNOON FORECAST IS
THE POTENTIAL FOR ISOLATED SHOWER/THUNDERSTORM DEVELOPMENT. LOW
LEVEL THICKNESS VALUES SUPPORT HIGHS AROUND THE MID 80S...AND WHEN
MODIFYING THE 12Z CHS SOUNDING...THAT WOULD GENERATE POSITIVE CAPE
VALUES. HOWEVER...WITH THE RIDGE BUILDING ALOFT AND HEIGHTS
RISING...MID LEVEL TEMPS ARE PROGGED TO WARM WHICH IS EXPECTED TO
THWART ANY CONVECTIVE DEVELOPMENT. COARSER RESOLUTION MODELS ARE
GENERATING SOME CONVECTION RIGHT ALONG THE COAST IN THE LATE
AFTERNOON...WHILE HIGHER RESOLUTION RUNS FAVOR THE DRY SIDE.
LOOKING THROUGH AFTERNOON RAP SOUNDINGS SHOWS THE POTENTIAL FOR
VERY THIN CAPE...PRIMARILY ACROSS SOUTHEAST SC. WITH THE WESTERLY
FLOW IN PLACE...HAVE DECIDED TO STICK WITH A DRY FORECAST AND
FAVOR THE HIGHER RESOLUTION MODEL RUNS. OTHERWISE...EXPECT A
DECENT GOOD DIURNAL CU FIELD BEGINNING IN THE EARLY AFTERNOON AND
THEN DISSIPATING IN THE EARLY EVENING WITH THE LOSS OF HEATING.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY/...
TONIGHT...THE AREA WILL REMAIN ALONG THE WESTERN PERIPHERY OF
ATLANTIC HIGH PRESSURE TONIGHT. ANY LINGERING CUMULUS WILL QUICKLY
DISSIPATE WITH THE LOSS OF INSOLATION LEAVING MAINLY CLEAR SKIES.
THERE WILL BE SOME INCREASE IN HIGH-LEVEL MOISTURE EARLY
FRIDAY...BUT THE MOISTURE LOOKS PRETTY THIN AT THIS TIME. A MOSTLY
CLEAR SKY CHARACTER SHOULD WORK. MODEL 925MB WIND FIELDS DO NOT
INCREASE SUBSTANTIALLY OVERNIGHT SO EXPECT THE BOUNDARY LAYER TO
DECOUPLE RATHER QUICKLY THIS EVENING WITH FAIRLY LIGHT WIND FIELDS
PREVAILING...ESPECIALLY INLAND. LOWS WILL BOTTOM OUT IN THE LOWER
60S MOST LOCATIONS WITH MID 60S AT THE COAST. COULD SEE A FEW
UPPER 50S IN A FEW OF THE NORMALLY COOLER SITES SUCH AS ALLENDALE
AND JAMESTOWN.
FRIDAY...QUIET CONDITIONS WILL PERSIST THROUGH EARLY WEEKEND WITH
WEAK HIGH PRESSURE AT THE SFC AND MID LVL RIDGING PEAKING ALOFT.
TEMPS WILL WARM CONSIDERABLY WITH SOUTHERLY FLOW IN PLACE UNDER
MOSTLY SUNNY SKIES. 1000-850 MB THICKNESSES FAVOR HIGH TEMPS IN THE
MID/UPPER 80S FRIDAY AFTERNOON...HIGHEST OVER INLAND AREAS IN
SOUTHEAST GEORGIA. FRIDAY NIGHT LOWS SHOULD REMAIN IN THE LOW/MID
60S AHEAD OF A COLD FRONT ADVANCING TO THE SOUTHEASTERN UNITED
STATES.
SATURDAY AND SUNDAY...CHANCES OF PRECIP WILL BEGIN TO INCREASE FOR
THE SECOND HALF OF THIS WEEKEND AS MID LVL RIDGING SLIDES EAST WHILE
SUBTLE H5 SHORTWAVES EJECT FROM THE SOUTHERN PLAINS TOWARDS THE
SOUTHEASTERN UNITED STATES. SHOWERS AND/OR THUNDERSTORM ACTIVITY
SHOULD INCREASE BY SATURDAY AFTERNOON/EVENING AS ISENTROPIC ASCENT
INCREASES AND BOUNDARY LAYER MOISTURE DEEPENS AHEAD OF A COLD FRONT
ADVANCING TOWARDS THE FORECAST AREA LATE. DESPITE INCREASING CLOUD
COVER...SFC TEMPS SHOULD PEAK IN THE LOW/MID 80S ON SATURDAY. PRECIP
COVERAGE SHOULD EXPAND SATURDAY NIGHT AS PWATS APPROACH 1.50-1.75
INCHES ALONG/AHEAD OF THE COLD FRONT.
AT THIS TIME...PRECIP ACTIVITY LOOKS TO PEAK AS THE COLD FRONT
PUSHES THROUGH THE FORECAST AREA SUNDAY MORNING. GIVEN THE TIME OF
COLD FROPA...THE CHANCE OF STRONGER THUNDERSTORMS WILL REMAIN LOW.
HOWEVER...SOME SHOWERS AND/OR THUNDERSTORMS MAY PRODUCE HEAVY RAIN
BEFORE THE COLD FRONT SHIFTS OFFSHORE. CONDITIONS WILL LIKELY
IMPROVE OVER THE AREA THROUGH SUNDAY EVENING AS HIGH PRESSURE BEGINS
TO BUILD IN BEHIND THE COLD FRONT SHIFTING OFFSHORE. GIVEN THE
AMOUNT OF CLOUD COVER AND SHOWER/THUNDERSTORM ACTIVITY...OVERALL
HIGH TEMPS WILL REMAIN COOLER ON SUNDAY...IN THE UPPER 70S TO AROUND
80.
&&
.LONG TERM /SUNDAY NIGHT THROUGH WEDNESDAY/...
A QUIET PERIOD OF WEATHER IS ANTICIPATED NEXT WEEK AS DRY AND COOLER
HIGH PRESSURE BUILDS IN BEHIND A COLD FRONT SHIFTING OVER THE
WESTERN ATLANTIC. MONDAY COULD START OFF BREEZY AS COOLER AIR SHIFTS
SOUTH OVER THE FORECAST AREA INITIALLY. OVERALL TEMPS WILL REMAIN IN
THE LOW/MID 70S MONDAY AND TUESDAY AS THE AREA REMAINS UNDER A
NORTHERLY FLOW. OVERNIGHT LOWS WILL ALSO BE COOL...IN THE UPPER 40S
TO LOWER 50S. TEMPS SHOULD THEN GRADUALLY WARM WEDNESDAY AND
THURSDAY AS SFC HIGH PRESSURE BECOMES CENTERED OVER THE SOUTHEASTERN
UNITED STATES WHILE A DOWNSLOPING WIND COMPONENT DEVELOPS OVER THE
FORECAST AREA. IN GENERAL...OVERALL TEMPS WILL WARM TO AROUND 80 ON
WEDNESDAY AND THEN INTO THE LOWER 80S ON THURSDAY.
&&
.AVIATION /15Z THURSDAY THROUGH MONDAY/...
VFR.
EXTENDED AVIATION OUTLOOK...LOW CHANCES OF MVFR CIGS/VSBYS WITH
COLD FRONTAL PASSAGE SATURDAY/SUNDAY.
&&
.MARINE...
TODAY AND TONIGHT...THERE ARE NO CONCERNS. A BROAD SOUTHERN FLOW
REGIME WILL PERSIST WITH SPEEDS GENERALLY 10-15 KT AND SEAS 2-4
FT.
FRIDAY THROUGH TUESDAY...MARINE CONDITIONS WILL REMAIN QUIET THROUGH
LATE WEEK AS HIGH PRESSURE REMAINS OVER THE WATERS. IN
GENERAL...WINDS WILL REMAIN AT OR BELOW 15 KTS...HIGHEST ALONG THE
COAST EACH AFTERNOON WITH SEABREEZE CIRCULATIONS. SEAS WILL REMAIN
AT OR BELOW 4 FT...HIGHEST OVER NORTHERN SC WATERS AND OUTER GEORGIA
WATERS. WINDS/SEAS WILL THEN GRADUALLY INCREASE/BUILD LATE WEEKEND
ALONG/AHEAD OF A COLD FRONT PASSING OVER THE WATERS ON SUNDAY.
ALTHOUGH CONDITIONS ARE EXPECTED TO REMAIN BELOW ADVISORY LEVELS
WITH COLD FROPA...COOL HIGH PRESSURE BEHIND THE FRONT SHOULD RESULT
IN WINDS OF 15-20 KTS ALONG WITH SEAS BUILDING TO 4-5 FT ON
MONDAY...HIGHEST OVER WATERS BEYOND 10 NM FROM THE COAST. CONDITIONS
WILL THEN IMPROVE BY TUESDAY AND REMAIN WELL BELOW ADVISORY LEVELS
THROUGH THE MIDDLE OF NEXT WEEK.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...BSH
SHORT TERM...DPB/ST
LONG TERM...DPB
AVIATION...ST
MARINE...DPB/ST
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
322 PM CDT THU MAY 9 2013
.MESOSCALE DISCUSSION...141 PM CDT
CONTINUING TO MONITOR OBSERVATIONAL TRENDS TOWARD STORM POTENTIAL
WITH A SLIGHT RISK FOR A FEW SEVERE STORMS ACROSS MAINLY THE
SOUTHEAST QUARTER OF THE CWA OR SO PRIMARILY IN THE TIME WINDOW OF
4 PM TO 9 PM.
SATELLITE IMAGERY EARLY THIS AFTERNOON INDICATES A WELL-DEFINED
SHORT WAVE...POSSIBLY CONVECTIVELY ENHANCED LOOKING BACK AT THE
PAST 12 HOURS...MOVING NORTHEAST FROM EAST CENTRAL MO. VAD
PROFILER DATA FROM LSX REVEALS 45 KT 700MB FLOW COINCIDENT WITH
THIS AND OTHER REGIONAL VAD DATA DEPICTS A LOW-LEVEL JET OF 35-40
KT NOSING UP IN ADVANCE OF THIS INTO CENTRAL/EAST CENTRAL IL.
AXES OF SHOWERS WITH STORMS CONTINUE TO REGENERATE IN THIS
FAVORED AREA...THOUGH MUCH OF THE LIGHTNING HAS HAD DIFFICULTY
THUS FAR REACHING NORTH OF I-74. LATEST HAND SURFACE ANALYSIS
PORTRAYS SOMEWHAT OF A MESSY PATTERN THANKS TO THE CONVECTIVE
ACTIVITY AND EVEN THE RAIN FROM EARLIER TODAY. THE SURFACE LOW
CONTINUES TO TAKE SHAPE ACROSS SOUTHEAST IA...THOUGH THE PRIMARY
WARM SECTOR IS SOMEWHAT WORKED OVER...WITH THE BEST UNTAPPED
HIGHER T/TD AIR ONLY AS FAR NORTH AS SOUTHERN IL. A CLEAR SWATH
WITH MAINLY ONLY SOME CIRRUS IS MOVING ACROSS THE AREA NORTH OF
THE SHOWER ACTIVITY AND DID ALLOW TEMPERATURES TO WARM INTO THE
70S ACROSS A LOT OF THE CWA.
SHOWERS WITH EMBEDDED STORMS SHOULD CONTINUE TO REGENERATE ACROSS
CENTRAL/EAST CENTRAL IL DURING THE MID TO LATE AFTERNOON WITH THE
AFOREMENTIONED SHORT WAVE AND LOW TO MID-LEVEL MOISTURE TRANSPORT
PROGRESSING NORTHEAST. WOULD EXPECT CONVECTION TO HAVE BETTER
CHANCES TO BECOME STRONGER IN FAR EASTERN IL TO WESTERN
IN...INCLUDING THE FAR SOUTHEAST CWA...AS THE MID-LEVEL FORCING
FOR ASCENT TRANSLATES OVER AN AIR MASS THAT IS MORE UNTAPPED.
MODIFIED RAP AND LAPS SOUNDINGS FROM NORTHWEST INDIANA DO CONTINUE
TO SHOW A CAP ALOFT IN MOST PLACES /THOUGH THE 78 DEGREES AT VPZ
BASICALLY HAS ERODED THAT/...WITH MLCAPE VALUES OF 500-800 J/KG
AND MUCAPE VALUES TOWARD 1200 J/KG. THIS INSTABILITY SHOULD NOT
INCREASE MUCH THROUGH THE COMING HOURS GIVEN THE CLOUDS AND LEAD
SHOWERS SPREADING IN. DEEP LAYER SHEAR IS FORECAST TO INCREASE TO
35-40 KT BY LATE AFTERNOON IN THIS AREA WHICH MAY SUPPORT SOME
TEMPORARY STRONGER ORGANIZED STORMS THAT COULD PRESENT AN ISOLATED
WIND THREAT. WHILE THERE LOOKS TO REMAIN A CHANCE FOR SCATTERED
CONVECTION LATER INTO THE EVE IN THESE AREAS AS THE SURFACE LOW
COMES ACROSS...THE MORE FOCUSED CONVECTION IS EXPECTED TO BE
ASSOCIATED EARLIER WITH THIS SHORT WAVE...AND CONVECTIVE ALLOWING
MODELS AGREE WITH THIS EVOLUTION.
FURTHER TO THE NORTH IN CHICAGO AND TOWARD ROCKFORD...WHILE THE
CLEARING HAS ALLOWED FOR SOME DESTABILIZATION...THE OVERALL
INSTABILITY REMAINS SOMEWHAT WEAK FOR WIDESPREAD STORM ACTIVITY.
THE POTENTIAL FOR RAIN WILL INCREASE QUICKLY AFTER 4 PM AND INTO
THE EVENING AS IMPROVED MOISTURE CONVERGENCE AHEAD OF THE WAVE
MOVES NORTH OVER THE AREA AND THEN PIVOTS WITH THE TRANSLATION OF
THE LOW ACROSS THE REGION. GOING QPF FORECASTS STILL LOOK ON
TRACK WITH 0.4 TO 0.75 INCHES OF RAIN IN MUCH OF NORTHERN AND
NORTHEAST IL.
MTF
&&
.DISCUSSION...
322 PM CDT
SHORT TERM...TONIGHT THROUGH SUNDAY
CONCERNS IN THIS PERIOD ARE WITH RAIN AND THUNDER CHANCES
TONIGHT...FOLLOWED BY TEMPERATURES SATURDAY NIGHT AND SUNDAY AS
THERE WILL BE A SIGNIFICANT COOL DOWN.
TONIGHT...WEAK SURFACE LOW WILL TRACK FROM FROM WESTERN ILLINOIS TO
NORTHERN INDIANA AND THEN TO SOUTHWEST LWR MI BY EARLY FRIDAY...WITH
OPEN UPPER WAVE ALSO PUSHING ACROSS REGION. AS THIS OCCURS...
WIDESPREAD SHRA WITH SOME EMBEDDED THUNDER INITIALLY WILL LIFT
NORTHEAST WITH CONVECTIVE ACTIVITY DIMINISHING AS ELEVATED
INSTABILITY DIMINISHES WITH TIME. PWAT OF 1.3 TO 1.4 INCHES AND GOOD
MOISTURE TRANSPORT AND CONVERGENCE WILL SUPPORT EFFICIENT RAINFALL
PRODUCTION AND THUS CANT RULE OUT MODERATE TO OCCASIONALLY HEAVY
RAIN RATES UNTIL THE LATE EVENING. AS LOW TRACKS ACROSS AREA...QUASI
STATIONARY FRONT THAT HAS BEEN LAID OUT ACROSS AREA THIS AFTERNOON
WILL PUSH SOUTH AS A COLD FRONT THROUGH ALL BUT SOUTHEASTERN
CWA...WITH COOLER AIR MASS/IN THE 40S TO LOWER 50S FILTERING IN BY
EARLY FRIDAY.
MOST SHRA ACTIVITY SHOULD BE ISOLATED AT BEST ON FRIDAY...EXCEPT FOR
PERHAPS MORE SCATTERED SHRA AHEAD OF FRONT AS IT FINALLY CLEARS OUR
FAR SOUTHEAST BY EARLY AFTERNOON. MILDER START IN THIS AREA COULD
ALLOW HIGHS TO REACH MID TO UPPER 60S...WITH REST OF AREA AWAY FROM
LAKE GENERALLY IN THE LOWER 60S. BIG STORY FRIDAY WILL BE THE STRONG
PUSH OF NORTHERLY WINDS DOWN THE LENGTH OF LAKE MICHIGAN BRINGING
QUITE A CHILLY DAY...WITH HIGHS ONLY AROUND 50 AND WINDS GUSTING AS
HIGH AS 30 MPH.
FRIDAY NIGHT WILL BE DRY AND COOL WITH LOWS IN THE 40S...BUT
AN UNSEASONABLY DEEP UPPER TROUGH WILL PUSH INTO THE UPPER GREAT
LAKES REGION BY SATURDAY...WITH A STRONG COLD FRONT TRAILING FROM
SURFACE LOW PRESSURE. THIS FRONT SHOULD TOUCH OFF A FEW SCT SHRA AS
IT PUSHES THROUGH THE CWA ON SATURDAY DUE TO STEEPENING LOW LEVEL
LAPSE RATES...BUT THE MAIN FOCUS WILL BE THE 850 MB TEMPS COOLING TO
-3C TO -4C BY EARLY SUNDAY...LEAVING A COOL BUT MOSTLY SUNNY MOTHERS
DAY. SOME CONCERN WITH FROST POTENTIAL AS EARLY AS SATURDAY
NIGHT...BUT HIGH PRESSURE SHOULD BE FAR ENOUGH WEST TO MAINTAIN A
GRADIENT AND PRECLUDE FROST FORMATION. ACTUALLY A BIGGER CONCERN
SATURDAY NIGHT IS THAT WHETHER THERE IS FROST OR NOT...AIR TEMPS IN
OUTLYING AREAS COULD DIP TO OR BELOW FREEZING IN UNSEASONABLY COOL
AND DRY AIR MASS IN PLACE. IF THE SUB FREEZING TEMPS REALIZED ON
SOME GUIDANCE IS REALIZED...MAY NEED A FREEZE WATCH FOR PORTIONS OF
AREA SATURDAY NIGHT...AS WE ARE QUICKLY TRENDING TO FULL VEGETATION.
DESPITE FULL SUNSHINE ON MOTHERS DAY...CLIMO WITH 850 TEMPS SUBZERO
C ONLY SUPPORTS HIGHS IN THE MID TO UPPER 50S.
LONG TERM...SUNDAY NIGHT THROUGH THURSDAY...
CONCERNS IN THE LONG TERM WILL RAPIDLY SHIFT FROM COLD WEATHER
CONCERNS INITIALLY TO VERY WARM TEMPERATURES ON TUESDAY. HIGH
PRESSURE RIDGE AXIS WILL BE OVER THE REGION SUNDAY NIGHT YIELDING
MUCH LIGHTER WINDS. COUPLED WITH CLEAR SKIES AND DRY AIR MASS...WITH
DEWPOINTS ONLY AROUND 30...STAGE COULD BE SET FOR LOWS NEAR FREEZING
IN SOME AREAS EARLY MONDAY AND ALSO FROST POTENTIAL. AGAIN LOWERED
TEMPS FROM BLEND OF PREVIOUS FCST AND CONSENSUS GUIDANCE TO
GENERALLY MID 30S EXCEPT RIGHT IN THE CHICAGO HEAT ISLAND...WITH
NEAR FREEZING TEMPS IN TYPICALLY COLDER RURAL AND SUBURBAN LOCATIONS
WEST OF THE FOX RIVER. WILL ADD PATCHY FROST TO THE GRIDS FOR AREAS
AWAY FROM CHICAGO.
THEN EARLY NEXT WEEK...UPPER LEVEL RIDGE QUICKLY AMPLIFIES OVER THE
AREA...WITH RAPIDLY WARMING TEMPS ALOFT. ON MONDAY...HIGHS WILL WARM
NICELY TO THE MID 60S AFTER THE CHILLY START. THEN TUES...850 TEMPS
SOAR TO 18+ TO +20C OR HIGHER (NEW ECMWF HAS +23C! OVER NORTH
CENTRAL IL BY 00Z WEDS) IN GUSTY SOUTHWESTERLY BDRY LAYER FLOW. 850
MB CLIMO WOULD SUGGEST MID 80S AT A MINIUM IN MID MAY WITH
THESE TEMPS ALOFT. FCST SOUNDINGS SUGGEST HOW DEEP WE MIX COULD
BE A LIMITING FACTOR/IE. TO AROUND 900 MB ON THE GFS AND ECMWF.
AGAIN BUMPED TEMPERATURES UP FROM PREVIOUS FCST AND CONSENSUS BLEND
TO LOW TO MID 80S AND EVEN THIS COULD BE CONSERVATIVE WITH SUCH A
WARM AIR MASS IN PLACE ASSUMING THERE ARE NO LINGERING ISSUES WITH
WAA CLOUD COVER. EXTENDED GUIDANCE CONSISTENT IN FEATURING COLD
FRONT SLIPPING SOUTH INTO PORTION OF AREA ON WEDNESDAY...THOUGH
IT APPEARS IT WILL BE ANOTHER WARM DAY WITH HIGHS AT LEAST INTO
THE UPPER 70S TO AROUND 80. THERE ARE SOME DIFFERENCES ON
SHRA/TSRA CHANCES WITH THIS FRONT...AS NORTHERN CWA COULD BE
FAVORED WEDS AFTERNOON WITH BETTER CHANCES BY WEDNESDAY NIGHT.
GUIDANCE THEN DIVERGES ON HOW FAST FRONT PUSHES THROUGH AREA...AS
IT COULD STALL OUT THURSDAY AND EVEN INTO FRIDAY...KEEPING SHRA
AND TSRA CHANCES GOING.
RC
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 20Z...
* SHOWERS WITH ISOLATED/SCATTERED TSRA THIS AFTERNOON.
* SHOWERS THIS EVENING...ENDING OVERNIGHT.
* SOUTHERLY WINDS BECOMING EASTERLY BY EARLY EVENING THEN NORTH
BY LATE EVENING...WITH SOME GUSTS POSSIBLE OVERNIGHT.
* MVFR CIGS BY EARLY EVENING WITH IFR/LIFR CIGS DEVELOPING DURING
THE EVENING...IMPROVING TO MVFR FRIDAY MORNING. CMS
//DISCUSSION...UPDATED 18Z...
LINE OF SHRA/TSRA LIFTING NORTH ACROSS CENTRAL IL HAS BEGUN TO
WEAKEN AS ADDITIONAL TSRA LIFT NORTHEAST ACROSS EASTERN IL. WHILE
THIS ACTIVITY IS WEAKENING...HAVE ADJUSTED TIMING...A LITTLE
EARLIER...AS SOME SHOWER ACTIVITY WILL LIKELY REACH THE TERMINALS
BY MID AFTERNOON. ADDITIONAL SHOWERS AND PERHAPS ISOLATED TSRA
WILL CONTINUE TO DEVELOP/SPREAD NORTH ACROSS THE AREA THROUGH
EARLY THIS EVENING AS AN UPPER WAVE LIFTS NORTH. APPEARS THE BEST
THUNDER COVERAGE WILL REMAIN SOUTHEAST OF THE TERMINALS AND FOR
NOW HAVE MAINTAINED VCTS BUT TRENDS WILL NEED TO BE MONITORED FOR
UPDATES. AS AN AREA OF SURFACE LOW PRESSURE MOVES ACROSS THE AREA
LATE TONIGHT INTO THE EARLY OVERNIGHT HOURS...ADDITIONAL SHOWERS
WILL BE POSSIBLE.
THIS SURFACE LOW...AND THE LOCATION OF THE WARM FRONT AHEAD OF IT
THIS AFTERNOON WILL MAKE WIND DIRECTIONS PROBLEMATIC. SOUTHERLY
WINDS TO THE I-80 CORRIDOR LOOK ON TRACK BUT AT MDW/ORD...WINDS ON
ONE MINUTE DATA HAVE BEEN LIGHT WESTERLY TO LIGHT EASTERLY...AS
WELL AS CALM. WHILE GRADIENT REMAINS WEAK...APPEARS AS THE SURFACE
LOW APPROACHES...SOUTHEASTERLY WINDS WILL LIKELY PREVAIL AND THEN
SHIFT MORE EAST THEN NORTHEAST THIS EVENING BUT CONFIDENCE
REGARDING WINDS THROUGH THIS EVENING REMAINS LOW.
CIGS WILL LIKELY BEGIN TO FALL INTO MVFR AS PRECIP DEVELOPS AND AS
THE LOW LEVELS SATURATE WITH FLOW OFF THE LAKE...EXPECT CIGS TO
QUICKLY LOWER INTO IFR THIS EVENING AND AS THE SURFACE LOW
APPROACHES...CIGS LIKELY TO DROP INTO LIFR AND POSSIBLY VLIFR WITH
CIGS SLOWLY LIFTING FRIDAY MORNING AS THE LOW SHIFTS EAST. CMS
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
* MEDIUM CONFIDENCE REGARDING SHOWERS TIMING/TRENDS.
* LOW CONFIDENCE REGARDING TSRA THIS AFTERNOON INTO THIS EVENING.
* MEDIUM CONFIDENCE REGARDING CIGS THROUGH THE PERIOD.
* LOW CONFIDENCE REGARDING WINDS THIS AFTERNOON...MEDIUM
CONFIDENCE FOR THE REST OF THE PERIOD. CMS
//OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z...
FRIDAY NIGHT...CLEARING SKIES.
SATURDAY...VFR. GUSTY NORTHWEST WINDS.
SUNDAY AND MONDAY...VFR.
TUESDAY...STRONG SOUTHERLY WINDS...OTHERWISE VFR.
WEDNESDAY...CHANCE OF TSRA.
KJB
&&
.MARINE...
236 PM CDT
A SLOW MOVING COLD FRONT CONTINUES TO SAG SOUTH ACROSS LAKE
MICHIGAN THIS AFTERNOON. AN AREA OF LOW PRESSURE CENTERED NEAR
SOUTHEAST IOWA THIS AFTERNOON WILL LIFT NORTHEAST ALONG THIS
FRONTAL BOUNDARY...INTO NORTHERN ILLINOIS. THEN THE LOW PRESSURE
WILL CONTINUE TO SLIDE EAST ACROSS NORTHERN ILLINOIS FRIDAY
MORNING. MEANWHILE...THE GRADIENT BEHIND THE FRONTAL BOUNDARY WILL
TIGHTEN OVER THE NORTHERN PORTION OF THE LAKE...ALLOWING
NORTH/NORTHEAST WINDS TO INCREASE TO 15 TO 25 KT WITH OCCASIONAL
GUSTS TO 30 KT. THE NORTH WINDS WILL EVENTUALLY REACH THE SOUTHERN
PORTION OF LAKE MICHIGAN...ALLOWING FOR A LONG FETCH TO SETUP.
THIS POINTS TOWARDS BUILDING WAVES FOR THE SOUTHERN TIP OF THE
LAKE...INCLUDING BOTH THE ILLINOIS AND NORTHWEST INDIANA NEARSHORE
WATERS. HAVE HOISTED A SMALL CRAFT ADVISORY TO ACCOUNT FOR THE
HAZARDOUS WINDS/WAVES OVERNIGHT...ACROSS ILLINOIS NEARSHORE ZONES
FIRST...THEN REACHING NORTHWEST INDIANA NEARSHORE WATERS FRIDAY
MORNING.
WAVES WILL REMAIN HAZARDOUS THROUGH MUCH OF THE DAY
FRIDAY...DESPITE SLOWLY DIMINISHING WINDS AS A WEAK AREA OF HIGH
PRESSURE BUILDS OVER THE LAKE FRIDAY EVENING THROUGH EARLY
SATURDAY. THEN ANOTHER STRONG COLD FRONT WILL SLIDE EAST ACROSS
THE UPPER MIDWEST EARLY SATURDAY...REACHING LAKE MICHIGAN BY
MIDDAY. THIS WILL BRING ANOTHER TIGHT GRADIENT AND A RETURN TO
GUSTY NORTHWEST WINDS. AT THIS TIME GUSTS SHOULD BE AROUND 30
KT...HOWEVER A FEW GALE FORCE GUSTS MAY OCCUR.
LIGHT AND VARIABLE WINDS SET UP AGAIN FOR LATE SUNDAY INTO
MONDAY...AS ANOTHER AREA OF HIGH PRESSURE BUILDS ACROSS THE
WESTERN LAKES. THIS HIGH SHIFTS EAST MONDAY NIGHT...WITH YET
ANOTHER SHARP PRESSURE GRADIENT DEVLEOPING ACROSS THE WESTERN
LAKES TUESDAY WITH A POTENT STORM SYSTEM SLIDING EAST ACROSS
ONTARIO TUESDAY. THIS WILL ALLOW STRONG SOUTHERLY WINDS AHEAD OF
THE FRONTAL BOUNDARY.
BEACHLER
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742...1 AM FRIDAY TO 4
AM SATURDAY.
SMALL CRAFT ADVISORY...LMZ743-LMZ744-LMZ745...7 AM FRIDAY TO 4
AM SATURDAY.
&&
$$
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
301 PM CDT THU MAY 9 2013
.MESOSCALE DISCUSSION...
141 PM CDT
CONTINUING TO MONITOR OBSERVATIONAL TRENDS TOWARD STORM POTENTIAL
WITH A SLIGHT RISK FOR A FEW SEVERE STORMS ACROSS MAINLY THE
SOUTHEAST QUARTER OF THE CWA OR SO PRIMARILY IN THE TIME WINDOW OF
4 PM TO 9 PM.
SATELLITE IMAGERY EARLY THIS AFTERNOON INDICATES A WELL-DEFINED
SHORT WAVE...POSSIBLY CONVECTIVELY ENHANCED LOOKING BACK AT THE
PAST 12 HOURS...MOVING NORTHEAST FROM EAST CENTRAL MO. VAD
PROFILER DATA FROM LSX REVEALS 45 KT 700MB FLOW COINCIDENT WITH
THIS AND OTHER REGIONAL VAD DATA DEPICTS A LOW-LEVEL JET OF 35-40
KT NOSING UP IN ADVANCE OF THIS INTO CENTRAL/EAST CENTRAL IL.
AXES OF SHOWERS WITH STORMS CONTINUE TO REGENERATE IN THIS
FAVORED AREA...THOUGH MUCH OF THE LIGHTNING HAS HAD DIFFICULTY
THUS FAR REACHING NORTH OF I-74. LATEST HAND SURFACE ANALYSIS
PORTRAYS SOMEWHAT OF A MESSY PATTERN THANKS TO THE CONVECTIVE
ACTIVITY AND EVEN THE RAIN FROM EARLIER TODAY. THE SURFACE LOW
CONTINUES TO TAKE SHAPE ACROSS SOUTHEAST IA...THOUGH THE PRIMARY
WARM SECTOR IS SOMEWHAT WORKED OVER...WITH THE BEST UNTAPPED
HIGHER T/TD AIR ONLY AS FAR NORTH AS SOUTHERN IL. A CLEAR SWATH
WITH MAINLY ONLY SOME CIRRUS IS MOVING ACROSS THE AREA NORTH OF
THE SHOWER ACTIVITY AND DID ALLOW TEMPERATURES TO WARM INTO THE
70S ACROSS A LOT OF THE CWA.
SHOWERS WITH EMBEDDED STORMS SHOULD CONTINUE TO REGENERATE ACROSS
CENTRAL/EAST CENTRAL IL DURING THE MID TO LATE AFTERNOON WITH THE
AFOREMENTIONED SHORT WAVE AND LOW TO MID-LEVEL MOISTURE TRANSPORT
PROGRESSING NORTHEAST. WOULD EXPECT CONVECTION TO HAVE BETTER
CHANCES TO BECOME STRONGER IN FAR EASTERN IL TO WESTERN
IN...INCLUDING THE FAR SOUTHEAST CWA...AS THE MID-LEVEL FORCING
FOR ASCENT TRANSLATES OVER AN AIR MASS THAT IS MORE UNTAPPED.
MODIFIED RAP AND LAPS SOUNDINGS FROM NORTHWEST INDIANA DO CONTINUE
TO SHOW A CAP ALOFT IN MOST PLACES /THOUGH THE 78 DEGREES AT VPZ
BASICALLY HAS ERODED THAT/...WITH MLCAPE VALUES OF 500-800 J/KG
AND MUCAPE VALUES TOWARD 1200 J/KG. THIS INSTABILITY SHOULD NOT
INCREASE MUCH THROUGH THE COMING HOURS GIVEN THE CLOUDS AND LEAD
SHOWERS SPREADING IN. DEEP LAYER SHEAR IS FORECAST TO INCREASE TO
35-40 KT BY LATE AFTERNOON IN THIS AREA WHICH MAY SUPPORT SOME
TEMPORARY STRONGER ORGANIZED STORMS THAT COULD PRESENT AN ISOLATED
WIND THREAT. WHILE THERE LOOKS TO REMAIN A CHANCE FOR SCATTERED
CONVECTION LATER INTO THE EVE IN THESE AREAS AS THE SURFACE LOW
COMES ACROSS...THE MORE FOCUSED CONVECTION IS EXPECTED TO BE
ASSOCIATED EARLIER WITH THIS SHORT WAVE...AND CONVECTIVE ALLOWING
MODELS AGREE WITH THIS EVOLUTION.
FURTHER TO THE NORTH IN CHICAGO AND TOWARD ROCKFORD...WHILE THE
CLEARING HAS ALLOWED FOR SOME DESTABILIZATION...THE OVERALL
INSTABILITY REMAINS SOMEWHAT WEAK FOR WIDESPREAD STORM ACTIVITY.
THE POTENTIAL FOR RAIN WILL INCREASE QUICKLY AFTER 4 PM AND INTO
THE EVENING AS IMPROVED MOISTURE CONVERGENCE AHEAD OF THE WAVE
MOVES NORTH OVER THE AREA AND THEN PIVOTS WITH THE TRANSLATION OF
THE LOW ACROSS THE REGION. GOING QPF FORECASTS STILL LOOK ON
TRACK WITH 0.4 TO 0.75 INCHES OF RAIN IN MUCH OF NORTHERN AND
NORTHEAST IL.
MTF
&&
.DISCUSSION...
354 AM CDT
IN THE NEAR TERM...CLOSED MID-LEVEL CIRCULATION WAS LOCATED NEAR
SIOUX FALLS EARLY THIS AM...WITH ADDITIONAL SHORT WAVE ENERGY AND
ASSOCIATED CONVECTIVE CLUSTERS OVER OKLAHOMA/KANSAS. UPPER LOW IS
EXPECTED TO OPEN UP AND PHASE WITH SOUTHERN ENERGY INTO A POSITIVE
TILT TROUGH WHICH WILL MOVE SLOWLY EAST ACROSS THE REGION THROUGH
FRIDAY. WEAK SURFACE LOW PRESSURE OVER NORTHEAST KANSAS WILL DEEPEN
SLIGHTLY IN THE PROCESS...AND MOVE TO SOUTHEAST IA/WESTERN IL BY
THIS EVENING. SOUTHERLY 25-35 KT LOW LEVEL JET AND ASSOCIATED
MOISTURE TRANSPORT CURRENTLY FOCUSED INTO OK/KS/WESTERN MO WILL
GRADUALLY VEER INTO IL DURING THE DAY...AFFECTING OUR CWA
PARTICULARLY FROM LATE MORNING THROUGH THIS AFTERNOON/EARLY
EVENING. WITH SURFACE LOW PROGGED ACROSS CENTRAL/NORTHERN IL THIS
AFTERNOON AND EVENING...EFFECTIVE WARM FRONT DEVELOPS WEST-EAST
ACROSS THE SOUTHERN HALF OF THE CWA. FORECAST SOUNDINGS INDICATE
BETWEEN 500-1200 J/KG MLCAPE IN THE WARM SECTOR ALONG/SOUTH OF THE
FRONT...WHILE MID LEVEL LAPSE RATES FARTHER NORTH REMAIN MARGINAL
BUT LIKELY SUFFICIENT FOR OCCASIONAL THUNDER THERE. WHILE CLOUD
COVER AND PRECIP COVERAGE MAY LIMIT SFC/NEAR SFC BASED
DESTABILIZATION SOMEWHAT...PRESENCE OF 30-40 KT MID LEVEL FLOW AND
25-35 KT 0-6 KM BULK SHEAR DOES SUPPORT ORGANIZED CONVECTION. LINE
SEGMENTS WITH ATTENDANT SEVERE WIND/HAIL THREAT ARE EXPECTED TO BE
THE MAIN SEVERE WEATHER THREAT...THOUGH BACKED LOW LEVEL FLOW
NEAR/ALONG THE WARM FRONT COULD SUPPORT MINIMAL TORNADO POTENTIAL
PARTICULARLY IF LESS CLOUD COVER/MORE INSTABILITY WERE TO OCCUR.
MORE WIDESPREAD ISSUE IS LIKELY TO BE POTENTIAL FOR RAINFALL AMOUNTS
IN EXCESS OF 1.0 INCHES WITH RAIN/STORMS AS PWATS INCREASE TO AROUND
1.35 INCHES BY LATE AFTERNOON/EVENING. HEAVIER RAIN AND
THUNDERSTORMS SHOULD GRADUALLY MOVE OFF TO THE EAST/SOUTHEAST OF THE
CWA LATER TONIGHT...AS SFC LOW AND COLD FRONT MOVE THROUGH AND AXIS
OF BEST LOW LEVEL MOISTURE TRANSPORT VEERS ACROSS IN/OH.
SHOWERY WEATHER WILL LIKELY CONTINUE INTO FRIDAY HOWEVER...AS SLOW
MOVING UPPER TROUGH TRAVERSES THE FORECAST AREA. COOLER AIR WILL
FILTER IN AS WELL...WITH TEMPS FALLING FROM TODAYS UPPER 60S-MID 70S
TO LOWER-MID 60S NORTH TO SOUTH...AND 50S ALONG LAKE MICHIGAN.
GUIDANCE REMAINS STEADFAST IN DIGGING STRONG SHORT WAVE INTO THE
REGION AND AMPLIFYING UPPER TROUGH ACROSS THE FRIDAY NIGHT AND
SATURDAY. AS ADVERTISED EARLIER...SHARP SURFACE COLD FRONT IS
EXPECTED TO PUSH THROUGH DURING THE MORNING/MIDDAY HOURS...WITH
TEMPS LIKELY FALLING INTO THE 50S BEHIND THE FRONT DURING THE
AFTERNOON. UNSEASONABLY COOL HIGH PRESSURE BUILDS ACROSS THE PLAINS
AND MISSISSIPPI VALLEY SATURDAY NIGHT...SETTING THE STAGE FOR A
CHILLY MOTHERS DAY. 850 MB TEMPS IN THE NEGATIVE SINGLE DIGITS
PORTEND AFTERNOON HIGHS STRUGGLING TO GET TO/ABOVE 60 ESPECIALLY
ACROSS NORTHEAST IL/NORTHWEST IN. LOWS WILL LIKELY DIP INTO THE 30S
IN SOME NORTHERN PARTS OF THE CWA SATURDAY NIGHT AND AGAIN SUNDAY
NIGHT. LOOKS LIKE ENOUGH GRADIENT/WIND TO PREVENT PATCHY FROST
DEVELOPMENT BEHIND THE FRONT SATURDAY NIGHT...THOUGH THERE COULD BE
SOME FROST IN COLDER MORE SHELTERED AREAS LATE SUNDAY NIGHT.
AS QUICKLY AS WE COOL DOWN OVER THE NEXT COUPLE OF DAYS...GUIDANCE
CONTINUES TO INDICATE THAT THE DEEP UPPER TROUGH WILL BE
PROGRESSIVE. UPPER RIDGING AND STRONG WARM ADVECTION LOOKS TO PUSH
OUR TEMPS BACK FIRMLY INTO THE 60S MONDAY...AND QUITE POSSIBLY THE
80S ESPECIALLY WEST BY TUESDAY AS 850 MB TEMPS APPROACH +20 C. WEAK
SLOW MOVING COOL FRONT SAGS ACROSS THE AREA WEDNESDAY TEMPERING THE
WARM-UP A BIT POTENTIALLY ACROSS THE NORTH...ALONG WITH THE NEXT
CHANCE OF SHOWERS/STORMS.
RATZER
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 20Z...
* SHOWERS WITH ISOLATED/SCATTERED TSRA THIS AFTERNOON.
* SHOWERS THIS EVENING...ENDING OVERNIGHT.
* SOUTHERLY WINDS BECOMING EASTERLY BY EARLY EVENING THEN NORTH
BY LATE EVENING...WITH SOME GUSTS POSSIBLE OVERNIGHT.
* MVFR CIGS BY EARLY EVENING WITH IFR/LIFR CIGS DEVELOPING DURING
THE EVENING...IMPROVING TO MVFR FRIDAY MORNING. CMS
//DISCUSSION...UPDATED 18Z...
LINE OF SHRA/TSRA LIFTING NORTH ACROSS CENTRAL IL HAS BEGUN TO
WEAKEN AS ADDITIONAL TSRA LIFT NORTHEAST ACROSS EASTERN IL. WHILE
THIS ACTIVITY IS WEAKENING...HAVE ADJUSTED TIMING...A LITTLE
EARLIER...AS SOME SHOWER ACTIVITY WILL LIKELY REACH THE TERMINALS
BY MID AFTERNOON. ADDITIONAL SHOWERS AND PERHAPS ISOLATED TSRA
WILL CONTINUE TO DEVELOP/SPREAD NORTH ACROSS THE AREA THROUGH
EARLY THIS EVENING AS AN UPPER WAVE LIFTS NORTH. APPEARS THE BEST
THUNDER COVERAGE WILL REMAIN SOUTHEAST OF THE TERMINALS AND FOR
NOW HAVE MAINTAINED VCTS BUT TRENDS WILL NEED TO BE MONITORED FOR
UPDATES. AS AN AREA OF SURFACE LOW PRESSURE MOVES ACROSS THE AREA
LATE TONIGHT INTO THE EARLY OVERNIGHT HOURS...ADDITIONAL SHOWERS
WILL BE POSSIBLE.
THIS SURFACE LOW...AND THE LOCATION OF THE WARM FRONT AHEAD OF IT
THIS AFTERNOON WILL MAKE WIND DIRECTIONS PROBLEMATIC. SOUTHERLY
WINDS TO THE I-80 CORRIDOR LOOK ON TRACK BUT AT MDW/ORD...WINDS ON
ONE MINUTE DATA HAVE BEEN LIGHT WESTERLY TO LIGHT EASTERLY...AS
WELL AS CALM. WHILE GRADIENT REMAINS WEAK...APPEARS AS THE SURFACE
LOW APPROACHES...SOUTHEASTERLY WINDS WILL LIKELY PREVAIL AND THEN
SHIFT MORE EAST THEN NORTHEAST THIS EVENING BUT CONFIDENCE
REGARDING WINDS THROUGH THIS EVENING REMAINS LOW.
CIGS WILL LIKELY BEGIN TO FALL INTO MVFR AS PRECIP DEVELOPS AND AS
THE LOW LEVELS SATURATE WITH FLOW OFF THE LAKE...EXPECT CIGS TO
QUICKLY LOWER INTO IFR THIS EVENING AND AS THE SURFACE LOW
APPROACHES...CIGS LIKELY TO DROP INTO LIFR AND POSSIBLY VLIFR WITH
CIGS SLOWLY LIFTING FRIDAY MORNING AS THE LOW SHIFTS EAST. CMS
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
* MEDIUM CONFIDENCE REGARDING SHOWERS TIMING/TRENDS.
* LOW CONFIDENCE REGARDING TSRA THIS AFTERNOON INTO THIS EVENING.
* MEDIUM CONFIDENCE REGARDING CIGS THROUGH THE PERIOD.
* LOW CONFIDENCE REGARDING WINDS THIS AFTERNOON...MEDIUM
CONFIDENCE FOR THE REST OF THE PERIOD. CMS
//OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z...
FRIDAY NIGHT...CLEARING SKIES.
SATURDAY...VFR. GUSTY NORTHWEST WINDS.
SUNDAY AND MONDAY...VFR.
TUESDAY...STRONG SOUTHERLY WINDS...OTHERWISE VFR.
WEDNESDAY...CHANCE OF TSRA.
KJB
&&
.MARINE...
236 PM CDT
A SLOW MOVING COLD FRONT CONTINUES TO SAG SOUTH ACROSS LAKE
MICHIGAN THIS AFTERNOON. AN AREA OF LOW PRESSURE CENTERED NEAR
SOUTHEAST IOWA THIS AFTERNOON WILL LIFT NORTHEAST ALONG THIS
FRONTAL BOUNDARY...INTO NORTHERN ILLINOIS. THEN THE LOW PRESSURE
WILL CONTINUE TO SLIDE EAST ACROSS NORTHERN ILLINOIS FRIDAY
MORNING. MEANWHILE...THE GRADIENT BEHIND THE FRONTAL BOUNDARY WILL
TIGHTEN OVER THE NORTHERN PORTION OF THE LAKE...ALLOWING
NORTH/NORTHEAST WINDS TO INCREASE TO 15 TO 25 KT WITH OCCASIONAL
GUSTS TO 30 KT. THE NORTH WINDS WILL EVENTUALLY REACH THE SOUTHERN
PORTION OF LAKE MICHIGAN...ALLOWING FOR A LONG FETCH TO SETUP.
THIS POINTS TOWARDS BUILDING WAVES FOR THE SOUTHERN TIP OF THE
LAKE...INCLUDING BOTH THE ILLINOIS AND NORTHWEST INDIANA NEARSHORE
WATERS. HAVE HOISTED A SMALL CRAFT ADVISORY TO ACCOUNT FOR THE
HAZARDOUS WINDS/WAVES OVERNIGHT...ACROSS ILLINOIS NEARSHORE ZONES
FIRST...THEN REACHING NORTHWEST INDIANA NEARSHORE WATERS FRIDAY
MORNING.
WAVES WILL REMAIN HAZARDOUS THROUGH MUCH OF THE DAY
FRIDAY...DESPITE SLOWLY DIMINISHING WINDS AS A WEAK AREA OF HIGH
PRESSURE BUILDS OVER THE LAKE FRIDAY EVENING THROUGH EARLY
SATURDAY. THEN ANOTHER STRONG COLD FRONT WILL SLIDE EAST ACROSS
THE UPPER MIDWEST EARLY SATURDAY...REACHING LAKE MICHIGAN BY
MIDDAY. THIS WILL BRING ANOTHER TIGHT GRADIENT AND A RETURN TO
GUSTY NORTHWEST WINDS. AT THIS TIME GUSTS SHOULD BE AROUND 30
KT...HOWEVER A FEW GALE FORCE GUSTS MAY OCCUR.
LIGHT AND VARIABLE WINDS SET UP AGAIN FOR LATE SUNDAY INTO
MONDAY...AS ANOTHER AREA OF HIGH PRESSURE BUILDS ACROSS THE
WESTERN LAKES. THIS HIGH SHIFTS EAST MONDAY NIGHT...WITH YET
ANOTHER SHARP PRESSURE GRADIENT DEVLEOPING ACROSS THE WESTERN
LAKES TUESDAY WITH A POTENT STORM SYSTEM SLIDING EAST ACROSS
ONTARIO TUESDAY. THIS WILL ALLOW STRONG SOUTHERLY WINDS AHEAD OF
THE FRONTAL BOUNDARY.
BEACHLER
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742...1 AM FRIDAY TO 4
AM SATURDAY.
SMALL CRAFT ADVISORY...LMZ743-LMZ744-LMZ745...7 AM FRIDAY TO 4
AM SATURDAY.
&&
$$
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
247 PM CDT THU MAY 9 2013
.MESOSCALE DISCUSSION...
141 PM CDT
CONTINUING TO MONITOR OBSERVATIONAL TRENDS TOWARD STORM POTENTIAL
WITH A SLIGHT RISK FOR A FEW SEVERE STORMS ACROSS MAINLY THE
SOUTHEAST QUARTER OF THE CWA OR SO PRIMARILY IN THE TIME WINDOW OF
4 PM TO 9 PM.
SATELLITE IMAGERY EARLY THIS AFTERNOON INDICATES A WELL-DEFINED
SHORT WAVE...POSSIBLY CONVECTIVELY ENHANCED LOOKING BACK AT THE
PAST 12 HOURS...MOVING NORTHEAST FROM EAST CENTRAL MO. VAD
PROFILER DATA FROM LSX REVEALS 45 KT 700MB FLOW COINCIDENT WITH
THIS AND OTHER REGIONAL VAD DATA DEPICTS A LOW-LEVEL JET OF 35-40
KT NOSING UP IN ADVANCE OF THIS INTO CENTRAL/EAST CENTRAL IL.
AXES OF SHOWERS WITH STORMS CONTINUE TO REGENERATE IN THIS
FAVORED AREA...THOUGH MUCH OF THE LIGHTNING HAS HAD DIFFICULTY
THUS FAR REACHING NORTH OF I-74. LATEST HAND SURFACE ANALYSIS
PORTRAYS SOMEWHAT OF A MESSY PATTERN THANKS TO THE CONVECTIVE
ACTIVITY AND EVEN THE RAIN FROM EARLIER TODAY. THE SURFACE LOW
CONTINUES TO TAKE SHAPE ACROSS SOUTHEAST IA...THOUGH THE PRIMARY
WARM SECTOR IS SOMEWHAT WORKED OVER...WITH THE BEST UNTAPPED
HIGHER T/TD AIR ONLY AS FAR NORTH AS SOUTHERN IL. A CLEAR SWATH
WITH MAINLY ONLY SOME CIRRUS IS MOVING ACROSS THE AREA NORTH OF
THE SHOWER ACTIVITY AND DID ALLOW TEMPERATURES TO WARM INTO THE
70S ACROSS A LOT OF THE CWA.
SHOWERS WITH EMBEDDED STORMS SHOULD CONTINUE TO REGENERATE ACROSS
CENTRAL/EAST CENTRAL IL DURING THE MID TO LATE AFTERNOON WITH THE
AFOREMENTIONED SHORT WAVE AND LOW TO MID-LEVEL MOISTURE TRANSPORT
PROGRESSING NORTHEAST. WOULD EXPECT CONVECTION TO HAVE BETTER
CHANCES TO BECOME STRONGER IN FAR EASTERN IL TO WESTERN
IN...INCLUDING THE FAR SOUTHEAST CWA...AS THE MID-LEVEL FORCING
FOR ASCENT TRANSLATES OVER AN AIR MASS THAT IS MORE UNTAPPED.
MODIFIED RAP AND LAPS SOUNDINGS FROM NORTHWEST INDIANA DO CONTINUE
TO SHOW A CAP ALOFT IN MOST PLACES /THOUGH THE 78 DEGREES AT VPZ
BASICALLY HAS ERODED THAT/...WITH MLCAPE VALUES OF 500-800 J/KG
AND MUCAPE VALUES TOWARD 1200 J/KG. THIS INSTABILITY SHOULD NOT
INCREASE MUCH THROUGH THE COMING HOURS GIVEN THE CLOUDS AND LEAD
SHOWERS SPREADING IN. DEEP LAYER SHEAR IS FORECAST TO INCREASE TO
35-40 KT BY LATE AFTERNOON IN THIS AREA WHICH MAY SUPPORT SOME
TEMPORARY STRONGER ORGANIZED STORMS THAT COULD PRESENT AN ISOLATED
WIND THREAT. WHILE THERE LOOKS TO REMAIN A CHANCE FOR SCATTERED
CONVECTION LATER INTO THE EVE IN THESE AREAS AS THE SURFACE LOW
COMES ACROSS...THE MORE FOCUSED CONVECTION IS EXPECTED TO BE
ASSOCIATED EARLIER WITH THIS SHORT WAVE...AND CONVECTIVE ALLOWING
MODELS AGREE WITH THIS EVOLUTION.
FURTHER TO THE NORTH IN CHICAGO AND TOWARD ROCKFORD...WHILE THE
CLEARING HAS ALLOWED FOR SOME DESTABILIZATION...THE OVERALL
INSTABILITY REMAINS SOMEWHAT WEAK FOR WIDESPREAD STORM ACTIVITY.
THE POTENTIAL FOR RAIN WILL INCREASE QUICKLY AFTER 4 PM AND INTO
THE EVENING AS IMPROVED MOISTURE CONVERGENCE AHEAD OF THE WAVE
MOVES NORTH OVER THE AREA AND THEN PIVOTS WITH THE TRANSLATION OF
THE LOW ACROSS THE REGION. GOING QPF FORECASTS STILL LOOK ON
TRACK WITH 0.4 TO 0.75 INCHES OF RAIN IN MUCH OF NORTHERN AND
NORTHEAST IL.
MTF
&&
.DISCUSSION...
354 AM CDT
IN THE NEAR TERM...CLOSED MID-LEVEL CIRCULATION WAS LOCATED NEAR
SIOUX FALLS EARLY THIS AM...WITH ADDITIONAL SHORT WAVE ENERGY AND
ASSOCIATED CONVECTIVE CLUSTERS OVER OKLAHOMA/KANSAS. UPPER LOW IS
EXPECTED TO OPEN UP AND PHASE WITH SOUTHERN ENERGY INTO A POSITIVE
TILT TROUGH WHICH WILL MOVE SLOWLY EAST ACROSS THE REGION THROUGH
FRIDAY. WEAK SURFACE LOW PRESSURE OVER NORTHEAST KANSAS WILL DEEPEN
SLIGHTLY IN THE PROCESS...AND MOVE TO SOUTHEAST IA/WESTERN IL BY
THIS EVENING. SOUTHERLY 25-35 KT LOW LEVEL JET AND ASSOCIATED
MOISTURE TRANSPORT CURRENTLY FOCUSED INTO OK/KS/WESTERN MO WILL
GRADUALLY VEER INTO IL DURING THE DAY...AFFECTING OUR CWA
PARTICULARLY FROM LATE MORNING THROUGH THIS AFTERNOON/EARLY
EVENING. WITH SURFACE LOW PROGGED ACROSS CENTRAL/NORTHERN IL THIS
AFTERNOON AND EVENING...EFFECTIVE WARM FRONT DEVELOPS WEST-EAST
ACROSS THE SOUTHERN HALF OF THE CWA. FORECAST SOUNDINGS INDICATE
BETWEEN 500-1200 J/KG MLCAPE IN THE WARM SECTOR ALONG/SOUTH OF THE
FRONT...WHILE MID LEVEL LAPSE RATES FARTHER NORTH REMAIN MARGINAL
BUT LIKELY SUFFICIENT FOR OCCASIONAL THUNDER THERE. WHILE CLOUD
COVER AND PRECIP COVERAGE MAY LIMIT SFC/NEAR SFC BASED
DESTABILIZATION SOMEWHAT...PRESENCE OF 30-40 KT MID LEVEL FLOW AND
25-35 KT 0-6 KM BULK SHEAR DOES SUPPORT ORGANIZED CONVECTION. LINE
SEGMENTS WITH ATTENDANT SEVERE WIND/HAIL THREAT ARE EXPECTED TO BE
THE MAIN SEVERE WEATHER THREAT...THOUGH BACKED LOW LEVEL FLOW
NEAR/ALONG THE WARM FRONT COULD SUPPORT MINIMAL TORNADO POTENTIAL
PARTICULARLY IF LESS CLOUD COVER/MORE INSTABILITY WERE TO OCCUR.
MORE WIDESPREAD ISSUE IS LIKELY TO BE POTENTIAL FOR RAINFALL AMOUNTS
IN EXCESS OF 1.0 INCHES WITH RAIN/STORMS AS PWATS INCREASE TO AROUND
1.35 INCHES BY LATE AFTERNOON/EVENING. HEAVIER RAIN AND
THUNDERSTORMS SHOULD GRADUALLY MOVE OFF TO THE EAST/SOUTHEAST OF THE
CWA LATER TONIGHT...AS SFC LOW AND COLD FRONT MOVE THROUGH AND AXIS
OF BEST LOW LEVEL MOISTURE TRANSPORT VEERS ACROSS IN/OH.
SHOWERY WEATHER WILL LIKELY CONTINUE INTO FRIDAY HOWEVER...AS SLOW
MOVING UPPER TROUGH TRAVERSES THE FORECAST AREA. COOLER AIR WILL
FILTER IN AS WELL...WITH TEMPS FALLING FROM TODAYS UPPER 60S-MID 70S
TO LOWER-MID 60S NORTH TO SOUTH...AND 50S ALONG LAKE MICHIGAN.
GUIDANCE REMAINS STEADFAST IN DIGGING STRONG SHORT WAVE INTO THE
REGION AND AMPLIFYING UPPER TROUGH ACROSS THE FRIDAY NIGHT AND
SATURDAY. AS ADVERTISED EARLIER...SHARP SURFACE COLD FRONT IS
EXPECTED TO PUSH THROUGH DURING THE MORNING/MIDDAY HOURS...WITH
TEMPS LIKELY FALLING INTO THE 50S BEHIND THE FRONT DURING THE
AFTERNOON. UNSEASONABLY COOL HIGH PRESSURE BUILDS ACROSS THE PLAINS
AND MISSISSIPPI VALLEY SATURDAY NIGHT...SETTING THE STAGE FOR A
CHILLY MOTHERS DAY. 850 MB TEMPS IN THE NEGATIVE SINGLE DIGITS
PORTEND AFTERNOON HIGHS STRUGGLING TO GET TO/ABOVE 60 ESPECIALLY
ACROSS NORTHEAST IL/NORTHWEST IN. LOWS WILL LIKELY DIP INTO THE 30S
IN SOME NORTHERN PARTS OF THE CWA SATURDAY NIGHT AND AGAIN SUNDAY
NIGHT. LOOKS LIKE ENOUGH GRADIENT/WIND TO PREVENT PATCHY FROST
DEVELOPMENT BEHIND THE FRONT SATURDAY NIGHT...THOUGH THERE COULD BE
SOME FROST IN COLDER MORE SHELTERED AREAS LATE SUNDAY NIGHT.
AS QUICKLY AS WE COOL DOWN OVER THE NEXT COUPLE OF DAYS...GUIDANCE
CONTINUES TO INDICATE THAT THE DEEP UPPER TROUGH WILL BE
PROGRESSIVE. UPPER RIDGING AND STRONG WARM ADVECTION LOOKS TO PUSH
OUR TEMPS BACK FIRMLY INTO THE 60S MONDAY...AND QUITE POSSIBLY THE
80S ESPECIALLY WEST BY TUESDAY AS 850 MB TEMPS APPROACH +20 C. WEAK
SLOW MOVING COOL FRONT SAGS ACROSS THE AREA WEDNESDAY TEMPERING THE
WARM-UP A BIT POTENTIALLY ACROSS THE NORTH...ALONG WITH THE NEXT
CHANCE OF SHOWERS/STORMS.
RATZER
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 18Z...
* SHOWERS WITH ISOLATED/SCATTERED TSRA MID/LATE AFTERNOON.
* SHOWERS THIS EVENING...ENDING OVERNIGHT.
* LIGHT SOUTHEASTERLY WINDS BECOMING EAST BY EARLY EVENING THEN
NORTH BY LATE EVENING...WITH SOME GUSTS POSSIBLE OVERNIGHT.
* MVFR CIGS BY EARLY EVENING WITH IFR/LIFR CIGS DEVELOPING DURING
THE EVENING...IMPROVING TO MVFR FRIDAY MORNING. CMS
//DISCUSSION...UPDATED 18Z...
LINE OF SHRA/TSRA LIFTING NORTH ACROSS CENTRAL IL HAS BEGUN TO
WEAKEN AS ADDITIONAL TSRA LIFT NORTHEAST ACROSS EASTERN IL. WHILE
THIS ACTIVITY IS WEAKENING...HAVE ADJUSTED TIMING...A LITTLE
EARLIER...AS SOME SHOWER ACTIVITY WILL LIKELY REACH THE TERMINALS
BY MID AFTERNOON. ADDITIONAL SHOWERS AND PERHAPS ISOLATED TSRA
WILL CONTINUE TO DEVELOP/SPREAD NORTH ACROSS THE AREA THROUGH
EARLY THIS EVENING AS AN UPPER WAVE LIFTS NORTH. APPEARS THE BEST
THUNDER COVERAGE WILL REMAIN SOUTHEAST OF THE TERMINALS AND FOR
NOW HAVE MAINTAINED VCTS BUT TRENDS WILL NEED TO BE MONITORED FOR
UPDATES. AS AN AREA OF SURFACE LOW PRESSURE MOVES ACROSS THE AREA
LATE TONIGHT INTO THE EARLY OVERNIGHT HOURS...ADDITIONAL SHOWERS
WILL BE POSSIBLE.
THIS SURFACE LOW...AND THE LOCATION OF THE WARM FRONT AHEAD OF IT
THIS AFTERNOON WILL MAKE WIND DIRECTIONS PROBLEMATIC. SOUTHERLY
WINDS TO THE I-80 CORRIDOR LOOK ON TRACK BUT AT MDW/ORD...WINDS ON
ONE MINUTE DATA HAVE BEEN LIGHT WESTERLY TO LIGHT EASTERLY...AS
WELL AS CALM. WHILE GRADIENT REMAINS WEAK...APPEARS AS THE SURFACE
LOW APPROACHES...SOUTHEASTERLY WINDS WILL LIKELY PREVAIL AND THEN
SHIFT MORE EAST THEN NORTHEAST THIS EVENING BUT CONFIDENCE
REGARDING WINDS THROUGH THIS EVENING REMAINS LOW.
CIGS WILL LIKELY BEGIN TO FALL INTO MVFR AS PRECIP DEVELOPS AND AS
THE LOW LEVELS SATURATE WITH FLOW OFF THE LAKE...EXPECT CIGS TO
QUICKLY LOWER INTO IFR THIS EVENING AND AS THE SURFACE LOW
APPROACHES...CIGS LIKELY TO DROP INTO LIFR AND POSSIBLY VLIFR WITH
CIGS SLOWLY LIFTING FRIDAY MORNING AS THE LOW SHIFTS EAST. CMS
//ORD AND MDW CONFIDENCE...UPDATED 18Z...
* MEDIUM CONFIDENCE REGARDING SHOWERS TIMING/TRENDS.
* LOW CONFIDENCE REGARDING TSRA THIS AFTERNOON INTO THIS EVENING.
* MEDIUM CONFIDENCE REGARDING CIGS THROUGH THE PERIOD.
* LOW CONFIDENCE REGARDING WINDS THIS AFTERNOON...MEDIUM
CONFIDENCE FOR THE REST OF THE PERIOD. CMS
//OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z...
FRIDAY NIGHT...CLEARING SKIES.
SATURDAY...VFR. GUSTY NORTHWEST WINDS.
SUNDAY AND MONDAY...VFR.
TUESDAY...STRONG SOUTHERLY WINDS...OTHERWISE VFR.
WEDNESDAY...CHANCE OF TSRA.
KJB
&&
.MARINE...
236 PM CDT
A SLOW MOVING COLD FRONT CONTINUES TO SAG SOUTH ACROSS LAKE
MICHIGAN THIS AFTERNOON. AN AREA OF LOW PRESSURE CENTERED NEAR
SOUTHEAST IOWA THIS AFTERNOON WILL LIFT NORTHEAST ALONG THIS
FRONTAL BOUNDARY...INTO NORTHERN ILLINOIS. THEN THE LOW PRESSURE
WILL CONTINUE TO SLIDE EAST ACROSS NORTHERN ILLINOIS FRIDAY
MORNING. MEANWHILE...THE GRADIENT BEHIND THE FRONTAL BOUNDARY WILL
TIGHTEN OVER THE NORTHERN PORTION OF THE LAKE...ALLOWING
NORTH/NORTHEAST WINDS TO INCREASE TO 15 TO 25 KT WITH OCCASIONAL
GUSTS TO 30 KT. THE NORTH WINDS WILL EVENTUALLY REACH THE SOUTHERN
PORTION OF LAKE MICHIGAN...ALLOWING FOR A LONG FETCH TO SETUP.
THIS POINTS TOWARDS BUILDING WAVES FOR THE SOUTHERN TIP OF THE
LAKE...INCLUDING BOTH THE ILLINOIS AND NORTHWEST INDIANA NEARSHORE
WATERS. HAVE HOISTED A SMALL CRAFT ADVISORY TO ACCOUNT FOR THE
HAZARDOUS WINDS/WAVES OVERNIGHT...ACROSS ILLINOIS NEARSHORE ZONES
FIRST...THEN REACHING NORTHWEST INDIANA NEARSHORE WATERS FRIDAY
MORNING.
WAVES WILL REMAIN HAZARDOUS THROUGH MUCH OF THE DAY
FRIDAY...DESPITE SLOWLY DIMINISHING WINDS AS A WEAK AREA OF HIGH
PRESSURE BUILDS OVER THE LAKE FRIDAY EVENING THROUGH EARLY
SATURDAY. THEN ANOTHER STRONG COLD FRONT WILL SLIDE EAST ACROSS
THE UPPER MIDWEST EARLY SATURDAY...REACHING LAKE MICHIGAN BY
MIDDAY. THIS WILL BRING ANOTHER TIGHT GRADIENT AND A RETURN TO
GUSTY NORTHWEST WINDS. AT THIS TIME GUSTS SHOULD BE AROUND 30
KT...HOWEVER A FEW GALE FORCE GUSTS MAY OCCUR.
LIGHT AND VARIABLE WINDS SET UP AGAIN FOR LATE SUNDAY INTO
MONDAY...AS ANOTHER AREA OF HIGH PRESSURE BUILDS ACROSS THE
WESTERN LAKES. THIS HIGH SHIFTS EAST MONDAY NIGHT...WITH YET
ANOTHER SHARP PRESSURE GRADIENT DEVLEOPING ACROSS THE WESTERN
LAKES TUESDAY WITH A POTENT STORM SYSTEM SLIDING EAST ACROSS
ONTARIO TUESDAY. THIS WILL ALLOW STRONG SOUTHERLY WINDS AHEAD OF
THE FRONTAL BOUNDARY.
BEACHLER
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742...1 AM FRIDAY TO 4
AM SATURDAY.
SMALL CRAFT ADVISORY...LMZ743-LMZ744-LMZ745...7 AM FRIDAY TO 4
AM SATURDAY.
&&
$$
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AREA FORECAST DISCUSSION...UPDATED
NWS CHICAGO/ROMEOVILLE IL
148 PM CDT THU MAY 9 2013
.MESOSCALE DISCUSSION...
141 PM CDT
CONTINUING TO MONITOR OBSERVATIONAL TRENDS TOWARD STORM POTENTIAL
WITH A SLIGHT RISK FOR A FEW SEVERE STORMS ACROSS MAINLY THE
SOUTHEAST QUARTER OF THE CWA OR SO PRIMARILY IN THE TIME WINDOW OF
4 PM TO 9 PM.
SATELLITE IMAGERY EARLY THIS AFTERNOON INDICATES A WELL-DEFINED
SHORT WAVE...POSSIBLY CONVECTIVELY ENHANCED LOOKING BACK AT THE
PAST 12 HOURS...MOVING NORTHEAST FROM EAST CENTRAL MO. VAD
PROFILER DATA FROM LSX REVEALS 45 KT 700MB FLOW COINCIDENT WITH
THIS AND OTHER REGIONAL VAD DATA DEPICTS A LOW-LEVEL JET OF 35-40
KT NOSING UP IN ADVANCE OF THIS INTO CENTRAL/EAST CENTRAL IL.
AXES OF SHOWERS WITH STORMS CONTINUE TO REGENERATE IN THIS
FAVORED AREA...THOUGH MUCH OF THE LIGHTNING HAS HAD DIFFICULTY
THUS FAR REACHING NORTH OF I-74. LATEST HAND SURFACE ANALYSIS
PORTRAYS SOMEWHAT OF A MESSY PATTERN THANKS TO THE CONVECTIVE
ACTIVITY AND EVEN THE RAIN FROM EARLIER TODAY. THE SURFACE LOW
CONTINUES TO TAKE SHAPE ACROSS SOUTHEAST IA...THOUGH THE PRIMARY
WARM SECTOR IS SOMEWHAT WORKED OVER...WITH THE BEST UNTAPPED
HIGHER T/TD AIR ONLY AS FAR NORTH AS SOUTHERN IL. A CLEAR SWATH
WITH MAINLY ONLY SOME CIRRUS IS MOVING ACROSS THE AREA NORTH OF
THE SHOWER ACTIVITY AND DID ALLOW TEMPERATURES TO WARM INTO THE
70S ACROSS A LOT OF THE CWA.
SHOWERS WITH EMBEDDED STORMS SHOULD CONTINUE TO REGENERATE ACROSS
CENTRAL/EAST CENTRAL IL DURING THE MID TO LATE AFTERNOON WITH THE
AFOREMENTIONED SHORT WAVE AND LOW TO MID-LEVEL MOISTURE TRANSPORT
PROGRESSING NORTHEAST. WOULD EXPECT CONVECTION TO HAVE BETTER
CHANCES TO BECOME STRONGER IN FAR EASTERN IL TO WESTERN
IN...INCLUDING THE FAR SOUTHEAST CWA...AS THE MID-LEVEL FORCING
FOR ASCENT TRANSLATES OVER AN AIR MASS THAT IS MORE UNTAPPED.
MODIFIED RAP AND LAPS SOUNDINGS FROM NORTHWEST INDIANA DO CONTINUE
TO SHOW A CAP ALOFT IN MOST PLACES /THOUGH THE 78 DEGREES AT VPZ
BASICALLY HAS ERODED THAT/...WITH MLCAPE VALUES OF 500-800 J/KG
AND MUCAPE VALUES TOWARD 1200 J/KG. THIS INSTABILITY SHOULD NOT
INCREASE MUCH THROUGH THE COMING HOURS GIVEN THE CLOUDS AND LEAD
SHOWERS SPREADING IN. DEEP LAYER SHEAR IS FORECAST TO INCREASE TO
35-40 KT BY LATE AFTERNOON IN THIS AREA WHICH MAY SUPPORT SOME
TEMPORARY STRONGER ORGANIZED STORMS THAT COULD PRESENT AN ISOLATED
WIND THREAT. WHILE THERE LOOKS TO REMAIN A CHANCE FOR SCATTERED
CONVECTION LATER INTO THE EVE IN THESE AREAS AS THE SURFACE LOW
COMES ACROSS...THE MORE FOCUSED CONVECTION IS EXPECTED TO BE
ASSOCIATED EARLIER WITH THIS SHORT WAVE...AND CONVECTIVE ALLOWING
MODELS AGREE WITH THIS EVOLUTION.
FURTHER TO THE NORTH IN CHICAGO AND TOWARD ROCKFORD...WHILE THE
CLEARING HAS ALLOWED FOR SOME DESTABILIZATION...THE OVERALL
INSTABILITY REMAINS SOMEWHAT WEAK FOR WIDESPREAD STORM ACTIVITY.
THE POTENTIAL FOR RAIN WILL INCREASE QUICKLY AFTER 4 PM AND INTO
THE EVENING AS IMPROVED MOISTURE CONVERGENCE AHEAD OF THE WAVE
MOVES NORTH OVER THE AREA AND THEN PIVOTS WITH THE TRANSLATION OF
THE LOW ACROSS THE REGION. GOING QPF FORECASTS STILL LOOK ON
TRACK WITH 0.4 TO 0.75 INCHES OF RAIN IN MUCH OF NORTHERN AND
NORTHEAST IL.
MTF
&&
.DISCUSSION...
354 AM CDT
IN THE NEAR TERM...CLOSED MID-LEVEL CIRCULATION WAS LOCATED NEAR
SIOUX FALLS EARLY THIS AM...WITH ADDITIONAL SHORT WAVE ENERGY AND
ASSOCIATED CONVECTIVE CLUSTERS OVER OKLAHOMA/KANSAS. UPPER LOW IS
EXPECTED TO OPEN UP AND PHASE WITH SOUTHERN ENERGY INTO A POSITIVE
TILT TROUGH WHICH WILL MOVE SLOWLY EAST ACROSS THE REGION THROUGH
FRIDAY. WEAK SURFACE LOW PRESSURE OVER NORTHEAST KANSAS WILL DEEPEN
SLIGHTLY IN THE PROCESS...AND MOVE TO SOUTHEAST IA/WESTERN IL BY
THIS EVENING. SOUTHERLY 25-35 KT LOW LEVEL JET AND ASSOCIATED
MOISTURE TRANSPORT CURRENTLY FOCUSED INTO OK/KS/WESTERN MO WILL
GRADUALLY VEER INTO IL DURING THE DAY...AFFECTING OUR CWA
PARTICULARLY FROM LATE MORNING THROUGH THIS AFTERNOON/EARLY
EVENING. WITH SURFACE LOW PROGGED ACROSS CENTRAL/NORTHERN IL THIS
AFTERNOON AND EVENING...EFFECTIVE WARM FRONT DEVELOPS WEST-EAST
ACROSS THE SOUTHERN HALF OF THE CWA. FORECAST SOUNDINGS INDICATE
BETWEEN 500-1200 J/KG MLCAPE IN THE WARM SECTOR ALONG/SOUTH OF THE
FRONT...WHILE MID LEVEL LAPSE RATES FARTHER NORTH REMAIN MARGINAL
BUT LIKELY SUFFICIENT FOR OCCASIONAL THUNDER THERE. WHILE CLOUD
COVER AND PRECIP COVERAGE MAY LIMIT SFC/NEAR SFC BASED
DESTABILIZATION SOMEWHAT...PRESENCE OF 30-40 KT MID LEVEL FLOW AND
25-35 KT 0-6 KM BULK SHEAR DOES SUPPORT ORGANIZED CONVECTION. LINE
SEGMENTS WITH ATTENDANT SEVERE WIND/HAIL THREAT ARE EXPECTED TO BE
THE MAIN SEVERE WEATHER THREAT...THOUGH BACKED LOW LEVEL FLOW
NEAR/ALONG THE WARM FRONT COULD SUPPORT MINIMAL TORNADO POTENTIAL
PARTICULARLY IF LESS CLOUD COVER/MORE INSTABILITY WERE TO OCCUR.
MORE WIDESPREAD ISSUE IS LIKELY TO BE POTENTIAL FOR RAINFALL AMOUNTS
IN EXCESS OF 1.0 INCHES WITH RAIN/STORMS AS PWATS INCREASE TO AROUND
1.35 INCHES BY LATE AFTERNOON/EVENING. HEAVIER RAIN AND
THUNDERSTORMS SHOULD GRADUALLY MOVE OFF TO THE EAST/SOUTHEAST OF THE
CWA LATER TONIGHT...AS SFC LOW AND COLD FRONT MOVE THROUGH AND AXIS
OF BEST LOW LEVEL MOISTURE TRANSPORT VEERS ACROSS IN/OH.
SHOWERY WEATHER WILL LIKELY CONTINUE INTO FRIDAY HOWEVER...AS SLOW
MOVING UPPER TROUGH TRAVERSES THE FORECAST AREA. COOLER AIR WILL
FILTER IN AS WELL...WITH TEMPS FALLING FROM TODAYS UPPER 60S-MID 70S
TO LOWER-MID 60S NORTH TO SOUTH...AND 50S ALONG LAKE MICHIGAN.
GUIDANCE REMAINS STEADFAST IN DIGGING STRONG SHORT WAVE INTO THE
REGION AND AMPLIFYING UPPER TROUGH ACROSS THE FRIDAY NIGHT AND
SATURDAY. AS ADVERTISED EARLIER...SHARP SURFACE COLD FRONT IS
EXPECTED TO PUSH THROUGH DURING THE MORNING/MIDDAY HOURS...WITH
TEMPS LIKELY FALLING INTO THE 50S BEHIND THE FRONT DURING THE
AFTERNOON. UNSEASONABLY COOL HIGH PRESSURE BUILDS ACROSS THE PLAINS
AND MISSISSIPPI VALLEY SATURDAY NIGHT...SETTING THE STAGE FOR A
CHILLY MOTHERS DAY. 850 MB TEMPS IN THE NEGATIVE SINGLE DIGITS
PORTEND AFTERNOON HIGHS STRUGGLING TO GET TO/ABOVE 60 ESPECIALLY
ACROSS NORTHEAST IL/NORTHWEST IN. LOWS WILL LIKELY DIP INTO THE 30S
IN SOME NORTHERN PARTS OF THE CWA SATURDAY NIGHT AND AGAIN SUNDAY
NIGHT. LOOKS LIKE ENOUGH GRADIENT/WIND TO PREVENT PATCHY FROST
DEVELOPMENT BEHIND THE FRONT SATURDAY NIGHT...THOUGH THERE COULD BE
SOME FROST IN COLDER MORE SHELTERED AREAS LATE SUNDAY NIGHT.
AS QUICKLY AS WE COOL DOWN OVER THE NEXT COUPLE OF DAYS...GUIDANCE
CONTINUES TO INDICATE THAT THE DEEP UPPER TROUGH WILL BE
PROGRESSIVE. UPPER RIDGING AND STRONG WARM ADVECTION LOOKS TO PUSH
OUR TEMPS BACK FIRMLY INTO THE 60S MONDAY...AND QUITE POSSIBLY THE
80S ESPECIALLY WEST BY TUESDAY AS 850 MB TEMPS APPROACH +20 C. WEAK
SLOW MOVING COOL FRONT SAGS ACROSS THE AREA WEDNESDAY TEMPERING THE
WARM-UP A BIT POTENTIALLY ACROSS THE NORTH...ALONG WITH THE NEXT
CHANCE OF SHOWERS/STORMS.
RATZER
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 18Z...
* SHOWERS WITH ISOLATED/SCATTERED TSRA MID/LATE AFTERNOON.
* SHOWERS THIS EVENING...ENDING OVERNIGHT.
* LIGHT SOUTHEASTERLY WINDS BECOMING EAST BY EARLY EVENING THEN
NORTH BY LATE EVENING...WITH SOME GUSTS POSSIBLE OVERNIGHT.
* MVFR CIGS BY EARLY EVENING WITH IFR/LIFR CIGS DEVELOPING DURING
THE EVENING...IMPROVING TO MVFR FRIDAY MORNING. CMS
//DISCUSSION...UPDATED 18Z...
LINE OF SHRA/TSRA LIFTING NORTH ACROSS CENTRAL IL HAS BEGUN TO
WEAKEN AS ADDITIONAL TSRA LIFT NORTHEAST ACROSS EASTERN IL. WHILE
THIS ACTIVITY IS WEAKENING...HAVE ADJUSTED TIMING...A LITTLE
EARLIER...AS SOME SHOWER ACTIVITY WILL LIKELY REACH THE TERMINALS
BY MID AFTERNOON. ADDITIONAL SHOWERS AND PERHAPS ISOLATED TSRA
WILL CONTINUE TO DEVELOP/SPREAD NORTH ACROSS THE AREA THROUGH
EARLY THIS EVENING AS AN UPPER WAVE LIFTS NORTH. APPEARS THE BEST
THUNDER COVERAGE WILL REMAIN SOUTHEAST OF THE TERMINALS AND FOR
NOW HAVE MAINTAINED VCTS BUT TRENDS WILL NEED TO BE MONITORED FOR
UPDATES. AS AN AREA OF SURFACE LOW PRESSURE MOVES ACROSS THE AREA
LATE TONIGHT INTO THE EARLY OVERNIGHT HOURS...ADDITIONAL SHOWERS
WILL BE POSSIBLE.
THIS SURFACE LOW...AND THE LOCATION OF THE WARM FRONT AHEAD OF IT
THIS AFTERNOON WILL MAKE WIND DIRECTIONS PROBLEMATIC. SOUTHERLY
WINDS TO THE I-80 CORRIDOR LOOK ON TRACK BUT AT MDW/ORD...WINDS ON
ONE MINUTE DATA HAVE BEEN LIGHT WESTERLY TO LIGHT EASTERLY...AS
WELL AS CALM. WHILE GRADIENT REMAINS WEAK...APPEARS AS THE SURFACE
LOW APPROACHES...SOUTHEASTERLY WINDS WILL LIKELY PREVAIL AND THEN
SHIFT MORE EAST THEN NORTHEAST THIS EVENING BUT CONFIDENCE
REGARDING WINDS THROUGH THIS EVENING REMAINS LOW.
CIGS WILL LIKELY BEGIN TO FALL INTO MVFR AS PRECIP DEVELOPS AND AS
THE LOW LEVELS SATURATE WITH FLOW OFF THE LAKE...EXPECT CIGS TO
QUICKLY LOWER INTO IFR THIS EVENING AND AS THE SURFACE LOW
APPROACHES...CIGS LIKELY TO DROP INTO LIFR AND POSSIBLY VLIFR WITH
CIGS SLOWLY LIFTING FRIDAY MORNING AS THE LOW SHIFTS EAST. CMS
//ORD AND MDW CONFIDENCE...UPDATED 18Z...
* MEDIUM CONFIDENCE REGARDING SHOWERS TIMING/TRENDS.
* LOW CONFIDENCE REGARDING TSRA THIS AFTERNOON INTO THIS EVENING.
* MEDIUM CONFIDENCE REGARDING CIGS THROUGH THE PERIOD.
* LOW CONFIDENCE REGARDING WINDS THIS AFTERNOON...MEDIUM
CONFIDENCE FOR THE REST OF THE PERIOD. CMS
//OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z...
FRIDAY NIGHT...CLEARING SKIES.
SATURDAY...VFR. GUSTY NORTHWEST WINDS.
SUNDAY AND MONDAY...VFR.
TUESDAY...STRONG SOUTHERLY WINDS...OTHERWISE VFR.
WEDNESDAY...CHANCE OF TSRA.
KJB
&&
.MARINE...
208 AM CDT
A COLD FRONT WILL DROP SOUTHWARD DOWN THE LAKE TODAY. IN THE WAKE OF
THIS FRONT...WINDS WILL BECOME NORTH AND INCREASE UP TO 25 TO 30 KT
FOR A PERIOD INTO FRIDAY MORNING. THIS SHOULD RESULT IN SMALL
CRAFT ADVISORY CONDITIONS FOR BOTH THE INDIANA AND ILLINOIS NEAR
SHORE WATERS LATER TONIGHT THROUGH FRIDAY EVENING...AS WAVES
CLIMB ABOVE 6 FT AND NORTHERLY WINDS GUST UP IN THE 25 TO 30 KT
RANGE.
IN ADDITION TO WINDS...A WEATHER DISTURBANCE IS EXPECTED TO RESULT
IN A SURFACE WAVE OF LOW PRESSURE...WHICH SHOULD MOVE ALONG THE
FRONTAL BOUNDARY JUST SOUTH OF THE LAKE TONIGHT. THIS LOOKS TO
RESULT IN PERIODS OF SHOWERS AND THUNDERSTORMS...ESPECIALLY ACROSS
THE SOUTHERN PORTION OF THE LAKE LATER TODAY AND TONIGHT.
THE WINDS SHOULD TO ABATE FOR A PERIOD LATE FRIDAY AND INTO SATURDAY
AS ANOTHER SURFACE RIDGE OF HIGH PRESSURE BUILDS OVER THE LAKE.
HOWEVER...ANOTHER COLD FRONT STILL LOOKS TO TAKE AIM ON THE LAKE
SATURDAY AFTERNOON. THIS WILL ONCE AGAIN LEAD TO A
PERIOD OF STRONGER NORTHWESTERLY WINDS INTO SUNDAY MORNING.
ANOTHER PERIOD OF LIGHT AND VARIABLE WINDS LOOKS TO SET UP AGAIN FOR
LATE SUNDAY AND INTO MONDAY OF NEXT WEEK AS ANOTHER AREA OF SURFACE
HIGH PRESSURE BUILDS ACROSS THE WESTERN LAKES. HOWEVER...ONCE THIS
HIGH SHIFTS EAST MONDAY NIGHT...IT APPEARS THAT A STRONG PRESSURE
GRADIENT WILL SET UP ACROSS THE WESTERN LAKES...AS A POTENT STORM
SYSTEM MOVES EASTWARD ACROSS CANADA. THIS LOOKS TO RESULT IN SOME
STRONG SOUTHERLY WINDS OVER THE LAKE FOR TUESDAY OF NEXT WEEK.
KJB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742...1 AM FRIDAY TO 4
AM SATURDAY.
SMALL CRAFT ADVISORY...LMZ743-LMZ744-LMZ745...7 AM FRIDAY TO 4
AM SATURDAY.
&&
$$
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AREA FORECAST DISCUSSION
NWS DES MOINES IA
1243 PM CDT THU MAY 9 2013
.SHORT TERM.../TODAY/
ISSUED AT 348 AM CDT THU MAY 9 2013
MAIN CONCERN THIS MORNING WILL BE CONVECTIVE TRENDS...ESPECIALLY
HEAVY RAIN POTENTIAL. COMPACT SHORT WAVE/PV ANOMALY CONTINUES TO
SLOWLY CROSS THE NE/IA BORDER. FORCING AHEAD OF FEATURE IS NOT
EXTREME...BUT COUPLED WEAK/MODERATE THERMODYNAMIC AND KINEMATIC
FORCING HAS SUSTAINED AND EVEN RECENTLY ENHANCED CONVECTION FROM SW
INTO CENTRAL IA. THIS IN SOME WAYS RESEMBLES A LOW END SHRS EVENT
BUT WITH LESS FAVORABLE ENVIRONMENT. SEVERE POTENTIAL HAS
DIMINISHED WITH NIL EFFECTIVE SHEAR AND MUCAPES ONLY SEVERAL
HUNDRED J/KG. HEAVY RAIN CONDITIONS ARE NOT GREAT EITHER WITH PWS
JUST OVER AN INCH AND WARM CLOUD DEPTHS UNDER 1K FT. HOWEVER MEAN
CELL MOTION IS CURRENTLY 230 AT ONLY 16KTS SO SUM ALL FACTORS
TOGETHER WITH SLOW MOVEMENT COULD STILL LEAD TO HEAVY RAINS WHICH
UNFORTUNATELY MAY IMPACT THE MORNING COMMUTE. ADAIR AND PERRY HAVE
ALREADY RECEIVED 1.7 INCHES SINCE MIDNIGHT. CONDITIONS CHANGE
LITTLE THROUGH THE MORNING WITH CATEGORICAL POPS...BUT OVERALL
FORCING DIMINISHES INTO THE AFTERNOON WITH LESS COVERAGE
ANTICIPATED. CANNOT ARGUE WITH 05Z HRRR DEPICTION TOO MUCH.
.LONG TERM.../TONIGHT THROUGH WEDNESDAY/
ISSUED AT 348 AM CDT THU MAY 9 2013
WE WILL BE CONTINUING TO DEAL WITH THE REMNANTS OF THE SOUTH DAKOTA
LOW AND THE SOUTHERN STREAM SHORT WAVE PUSHING ACROSS THE FORECAST
AREA TONIGHT. THE SLOW MOVEMENT OF THE STORMS IN THE WEAK FLOW OVER
IOWA HAS PROVEN TO MAKE EFFICIENT RAIN PRODUCING STORMS BUT WE LOSE
WHATEVER WEAK FORCING WE HAD IN PLACE FROM TODAY SO I DON`T SEE AS
MUCH RAINFALL TONIGHT.
SOME LINGERING PRECIP EXPECTED ACROSS THE SOUTHEAST INTO FRIDAY
MORNING THEN A BREAK AS WEAK HIGH PRESSURE BUILDS IN AT THE SURFACE
WHILE ALOFT WE ARE IN BETWEEN SYSTEMS. FRIDAY NIGHT INTO SATURDAY A
LARGE LOW PRESSURE SYSTEM OVER CANADA CARVES A TROUGH INTO THE UPPER
MIDWEST. AT THE SURFACE A STRONG COLD FRONT WILL WORK ACROSS THE
AREA BRINGING A SHOT FOR MORE RAIN AND MUCH COLDER TEMPERATURES ALONG
WITH BREEZY CONDITIONS FOR THE WEEKEND. TEMPERATURES WILL BE
DROPPING INTO THE LOW TO MID 30S SATURDAY NIGHT SO FROST HAS TO
ENTER THE THOUGHT PROCESS HERE BUT WINDS AT LEAST THROUGH THE
EVENING...AND PROBABLY ALL NIGHT ACROSS THE EAST...WILL STAY UP
ENOUGH TO MINIMIZE THE FROST THREAT. HOWEVER AT THIS POINT I THINK
IT IS ENOUGH OF A THREAT TO PUT IT IN THE FORECAST GRIDS ACROSS
NORTH FOR A FEW HOURS BEFORE DAYBREAK. THIS WILL NEED TO BE
MONITORED FOR THE POTENTIAL FOR MORE THAN JUST A MENTION.
THE COLD WILL BE SHORT LIVED AS A LARGE UPPER LEVEL RIDGE BUILDS
ACROSS THE ROCKIES THEN SHIFTS EAST EARLY NEXT WEEK. TUESDAY STILL
LOOKS VERY WARM AND WHILE I WAS NOT BOLD ENOUGH TO MENTION A 90
DEGREE READING I DID BUMP TEMPS UP INTO THE MID TO UPPER 80S. THE
UPPER RIDGE FLATTENS INTO MIDWEEK KNOCKING TEMPS BACK SEVERAL
DEGREES. A FRONTAL BOUNDARY WILL SAG INTO THE REGION PRODUCING A
CHANCE FOR THUNDERSTORMS TUESDAY NIGHT. TEMPERATURES THROUGH
MIDWEEK WHILE COOLER...WILL STILL BE SEASONAL INTO THURSDAY WITH
HIGHS IN THE 70S.
&&
.AVIATION...09/18Z
ISSUED AT 1240 PM CDT THU MAY 9 2013
UPPER LOW OVER IOWA WILL MOVE SLOWLY ESEWD WITH NUMEROUS SHOWERS
AND ISOLATED TSRA EXPECTED THIS AFTERNOON. AREAS OF IFR CIGS WILL
EXPAND SOUTH AND EAST AS TROF SHIFTS SOUTHEAST. EXPECT IFR CIGS
ACROSS THE TAF SITES TONIGHT WITH MVFR VSBYS. CONDITIONS WILL
IMPROVE ACROSS THE NRN TAFS EARLY FRIDAY MORNING WITH SKIES
CLEARING...AND IMPROVE TO MVFR CIGS ACROSS THE SRN SITES BY MID
MORNING.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
LONG TERM...FAB
AVIATION...MS
AREA FORECAST DISCUSSION
NWS DES MOINES IA
702 AM CDT THU MAY 9 2013
.SHORT TERM.../TODAY/
ISSUED AT 348 AM CDT THU MAY 9 2013
MAIN CONCERN THIS MORNING WILL BE CONVECTIVE TRENDS...ESPECIALLY
HEAVY RAIN POTENTIAL. COMPACT SHORT WAVE/PV ANOMALY CONTINUES TO
SLOWLY CROSS THE NE/IA BORDER. FORCING AHEAD OF FEATURE IS NOT
EXTREME...BUT COUPLED WEAK/MODERATE THERMODYNAMIC AND KINEMATIC
FORCING HAS SUSTAINED AND EVEN RECENTLY ENHANCED CONVECTION FROM SW
INTO CENTRAL IA. THIS IN SOME WAYS RESEMBLES A LOW END SHARS EVENT
BUT WITH LESS FAVORABLE ENVIRONMENT. SEVERE POTENTIAL HAS
DIMINISHED WITH NIL EFFECTIVE SHEAR AND MUCAPES ONLY SEVERAL HUNDRED
J/KG. HEAVY RAIN CONDITIONS ARE NOT GREAT EITHER WITH PWS JUST
OVER AN INCH AND WARM CLOUD DEPTHS UNDER 1K FT. HOWEVER MEAN CELL
MOTION IS CURRENTLY 230 AT ONLY 16KTS SO SUM ALL FACTORS TOGETHER
WITH SLOW MOVEMENT COULD STILL LEAD TO HEAVY RAINS WHICH
UNFORTUNATELY MAY IMPACT THE MORNING COMMUTE. ADAIR AND PERRY HAVE
ALREADY RECEIVED 1.7 INCHES SINCE MIDNIGHT. CONDITIONS CHANGE
LITTLE THROUGH THE MORNING WITH CATEGORICAL POPS...BUT OVERALL
FORCING DIMINISHES INTO THE AFTERNOON WITH LESS COVERAGE
ANTICIPATED. CANNOT ARGUE WITH 05Z HRRR DEPICTION TOO MUCH.
.LONG TERM.../TONIGHT THROUGH WEDNESDAY/
ISSUED AT 348 AM CDT THU MAY 9 2013
WE WILL BE CONTINUING TO DEAL WITH THE REMNANTS OF THE SOUTH DAKOTA
LOW AND THE SOUTHERN STREAM SHORT WAVE PUSHING ACROSS THE FORECAST
AREA TONIGHT. THE SLOW MOVEMENT OF THE STORMS IN THE WEAK FLOW OVER
IOWA HAS PROVEN TO MAKE EFFICIENT RAIN PRODUCING STORMS BUT WE LOSE
WHATEVER WEAK FORCING WE HAD IN PLACE FROM TODAY SO I DON`T SEE AS
MUCH RAINFALL TONIGHT.
SOME LINGERING PRECIP EXPECTED ACROSS THE SOUTHEAST INTO FRIDAY
MORNING THEN A BREAK AS WEAK HIGH PRESSURE BUILDS IN AT THE SURFACE
WHILE ALOFT WE ARE IN BETWEEN SYSTEMS. FRIDAY NIGHT INTO SATURDAY A
LARGE LOW PRESSURE SYSTEM OVER CANADA CARVES A TROUGH INTO THE UPPER
MIDWEST. AT THE SURFACE A STRONG COLD FRONT WILL WORK ACROSS THE
AREA BRINGING A SHOT FOR MORE RAIN AND MUCH COLDER TEMPERATURES ALONG
WITH BREEZY CONDITIONS FOR THE WEEKEND. TEMPERATURES WILL BE
DROPPING INTO THE LOW TO MID 30S SATURDAY NIGHT SO FROST HAS TO
ENTER THE THOUGHT PROCESS HERE BUT WINDS AT LEAST THROUGH THE
EVENING...AND PROBABLY ALL NIGHT ACROSS THE EAST...WILL STAY UP
ENOUGH TO MINIMIZE THE FROST THREAT. HOWEVER AT THIS POINT I THINK
IT IS ENOUGH OF A THREAT TO PUT IT IN THE FORECAST GRIDS ACROSS
NORTH FOR A FEW HOURS BEFORE DAYBREAK. THIS WILL NEED TO BE
MONITORED FOR THE POTENTIAL FOR MORE THAN JUST A MENTION.
THE COLD WILL BE SHORT LIVED AS A LARGE UPPER LEVEL RIDGE BUILDS
ACROSS THE ROCKIES THEN SHIFTS EAST EARLY NEXT WEEK. TUESDAY STILL
LOOKS VERY WARM AND WHILE I WAS NOT BOLD ENOUGH TO MENTION A 90
DEGREE READING I DID BUMP TEMPS UP INTO THE MID TO UPPER 80S. THE
UPPER RIDGE FLATTENS INTO MIDWEEK KNOCKING TEMPS BACK SEVERAL
DEGREES. A FRONTAL BOUNDARY WILL SAG INTO THE REGION PRODUCING A
CHANCE FOR THUNDERSTORMS TUESDAY NIGHT. TEMPERATURES THROUGH
MIDWEEK WHILE COOLER...WILL STILL BE SEASONAL INTO THURSDAY WITH
HIGHS IN THE 70S.
&&
.AVIATION...09/12Z
ISSUED AT 700 AM CDT THU MAY 9 2013
FORECAST WILL BE SOMEWHAT PROBLEMATIC WITH LOW CONFIDENCE THROUGH
THE PERIOD. CONDITIONS ARE QUITE VARIED ACROSS CENTRAL IA AND TAFS
SITES FROM VFR TO IFR AND EVEN LIFR FARTHER NW. SYSTEM PRODUCE
RECENT SHOWERS WILL MOVE SLOWLY TODAY WITH OCCASIONAL
SHOWERS...ESPECIALLY THIS MORNING. CONFIDENCE IN TIMING AND
LOCATION OF ANY ADDITIONAL PRECIP IS QUITE LOW SO WILL NOT INCLUDE
ANY OTHER MENTION OUTSIDE OF CURRENT TRENDS. THUNDER ALSO POSSIBLE
BUT POTENTIAL NOT GREAT ENOUGH TO INCLUDE AT THE MOMENT. CIGS WILL
LOWER AS SYSTEM PULLS AWAY AND NORTH WINDS INCREASE. CONFIDENCE
REMAINS LOW...BUT MOST LIKELY SCENARIO SEEMS TO BE JUST INTO IFR.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM/AVIATION...SMALL
LONG TERM...FAB
AREA FORECAST DISCUSSION
NWS DES MOINES IA
351 AM CDT THU MAY 9 2013
.SHORT TERM.../TODAY /...
ISSUED AT 348 AM CDT THU MAY 9 2013
MAIN CONCERN THIS MORNING WILL BE CONVECTIVE TRENDS...ESPECIALLY
HEAVY RAIN POTENTIAL. COMPACT SHORT WAVE/PV ANOMALY CONTINUES TO
SLOWLY CROSS THE NE/IA BORDER. FORCING AHEAD OF FEATURE IS NOT
EXTREME...BUT COUPLED WEAK/MODERATE THERMODYNAMIC AND KINEMATIC
FORCING HAS SUSTAINED AND EVEN RECENTLY ENHANCED CONVECTION FROM SW
INTO CENTRAL IA. THIS IN SOME WAYS RESEMBLES A LOW END SHARS EVENT
BUT WITH LESS FAVORABLE ENVIRONMENT. SEVERE POTENTIAL HAS
DIMINISHED WITH NIL EFFECTIVE SHEAR AND MUCAPES ONLY SEVERAL HUNDRED
J/KG. HEAVY RAIN CONDITIONS ARE NOT GREAT EITHER WITH PWS JUST
OVER AN INCH AND WARM CLOUD DEPTHS UNDER 1K FT. HOWEVER MEAN CELL
MOTION IS CURRENTLY 230 AT ONLY 16KTS SO SUM ALL FACTORS TOGETHER
WITH SLOW MOVEMENT COULD STILL LEAD TO HEAVY RAINS WHICH
UNFORTUNATELY MAY IMPACT THE MORNING COMMUTE. ADAIR AND PERRY HAVE
ALREADY RECEIVED 1.7 INCHES SINCE MIDNIGHT. CONDITIONS CHANGE
LITTLE THROUGH THE MORNING WITH CATEGORICAL POPS...BUT OVERALL
FORCING DIMINISHES INTO THE AFTERNOON WITH LESS COVERAGE
ANTICIPATED. CANNOT ARGUE WITH 05Z HRRR DEPICTION TOO MUCH.
.LONG TERM.../TONIGHT THROUGH WEDNESDAY/...
ISSUED AT 348 AM CDT THU MAY 9 2013
WE WILL BE CONTINUING TO DEAL WITH THE REMNANTS OF THE SOUTH DAKOTA
LOW AND THE SOUTHERN STREAM SHORT WAVE PUSHING ACROSS THE FORECAST
AREA TONIGHT. THE SLOW MOVEMENT OF THE STORMS IN THE WEAK FLOW OVER
IOWA HAS PROVEN TO MAKE EFFICIENT RAIN PRODUCING STORMS BUT WE LOSE
WHATEVER WEAK FORCING WE HAD IN PLACE FROM TODAY SO I DON`T SEE AS
MUCH RAINFALL TONIGHT.
SOME LINGERING PRECIP EXPECTED ACROSS THE SOUTHEAST INTO FRIDAY
MORNING THEN A BREAK AS WEAK HIGH PRESSURE BUILDS IN AT THE SURFACE
WHILE ALOFT WE ARE IN BETWEEN SYSTEMS. FRIDAY NIGHT INTO SATURDAY A
LARGE LOW PRESSURE SYSTEM OVER CANADA CARVES A TROUGH INTO THE UPPER
MIDWEST. AT THE SURFACE A STRONG COLD FRONT WILL WORK ACROSS THE
AREA BRINGING A SHOT FOR MORE RAIN AND MUCH COLDER TEMPERATURES ALONG
WITH BREEZY CONDITIONS FOR THE WEEKEND. TEMPERATURES WILL BE
DROPPING INTO THE LOW TO MID 30S SATURDAY NIGHT SO FROST HAS TO
ENTER THE THOUGHT PROCESS HERE BUT WINDS AT LEAST THROUGH THE
EVENING...AND PROBABLY ALL NIGHT ACROSS THE EAST...WILL STAY UP
ENOUGH TO MINIMIZE THE FROST THREAT. HOWEVER AT THIS POINT I THINK
IT IS ENOUGH OF A THREAT TO PUT IT IN THE FORECAST GRIDS ACROSS
NORTH FOR A FEW HOURS BEFORE DAYBREAK. THIS WILL NEED TO BE
MONITORED FOR THE POTENTIAL FOR MORE THAN JUST A MENTION.
THE COLD WILL BE SHORT LIVED AS A LARGE UPPER LEVEL RIDGE BUILDS
ACROSS THE ROCKIES THEN SHIFTS EAST EARLY NEXT WEEK. TUESDAY STILL
LOOKS VERY WARM AND WHILE I WAS NOT BOLD ENOUGH TO MENTION A 90
DEGREE READING I DID BUMP TEMPS UP INTO THE MID TO UPPER 80S. THE
UPPER RIDGE FLATTENS INTO MIDWEEK KNOCKING TEMPS BACK SEVERAL
DEGREES. A FRONTAL BOUNDARY WILL SAG INTO THE REGION PRODUCING A
CHANCE FOR THUNDERSTORMS TUESDAY NIGHT. TEMPERATURES THROUGH
MIDWEEK WHILE COOLER...WILL STILL BE SEASONAL INTO THURSDAY WITH
HIGHS IN THE 70S.
&&
.AVIATION...09/06Z
ISSUED AT 1159 PM CDT WED MAY 8 2013
AN AREA OF SHOWERS AND THUNDERSTORMS WILL MOVE ACROSS THE NORTH
THROUGH 09Z THEN EXPECT A BAND OF FOG AND STRATUS TO DEVELOP WITH
IFR OR LOWER CONDITIONS POSSIBLE THROUGH MID MORNING. ANOTHER AREA
OF THUNDERSTORMS WILL LIFT INTO SOUTHERN IOWA OVERNIGHT AND
PRIMARILY IMPACT KOTM AND KDSM. AREAS OF PRECIPITATION WILL
CONTINUE ON THURSDAY BEFORE GRADUALLY DIMINISHING LATER IN THE
AFTERNOON AND EVENING. POTENTIAL FOR LOW STRATUS MOVING INTO THE
AREA BEHIND A FRONTAL BOUNDARY IS INCREASING BY THE EVENING AS
WELL.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...SMALL
LONG TERM...FAB
AVIATION...DONAVON
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
335 PM CDT THU MAY 9 2013
...UPDATED LONG TERM SECTION...
.SYNOPSIS...
ISSUED AT 221 PM CDT THU MAY 9 2013
AN ELONGATED MID LEVEL VORTICITY AXIS WAS FOUND ACROSS THE CENTRAL
PLAINS TODAY COMPLETE WITH MOISTURE AND FAIRLY COOL TEMPERATURES.
UPPER AIR OBSERVATIONS AND RAP ANALYSIS INDICATED 500/700MB
TEMPERATURES AROUND -17C/0C RESPECTIVELY. SOME INSOLATION THROUGH
EARLY AFTERNOON RESULTED IN SURFACE TEMPERATURES WARMING INTO THE
UPPER 60S TO NEAR 70 DEGREES PARTICULARLY SOUTH OF THE ARKANSAS
RIVER. THE MID LEVEL MOISTURE AXIS WAS FOUND TO BE CENTERED FROM THE
CENTRAL ROCKIES THROUGH NORTHERN KANSAS AND MUCH OF NEBRASKA. THIS
LINED UP FAIRLY WELL WITH THE MEAN 500-700MB DEFORMATION AXIS. THE
SURFACE FRONT HAD PUSHED WELL SOUTH OF THE REGION DOWN INTO SOUTHERN
OKLAHOMA, SO SURFACE-BASED INSTABILITY WAS VERY LOW ACROSS
SOUTHWESTERN KANSAS.
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 221 PM CDT THU MAY 9 2013
THE MAIN FORECAST CHALLENGE IS PRECIPITATION CHANCES, COVERAGE, AND
INTENSITY THIS EVENING. THE MENTIONED DEFORMATION AXIS WILL LINGER
ACROSS SOUTHEASTERN COLORADO AND WESTERN KANSAS THROUGH THIS
EVENING. THE UPDATED FORECAST POP/WX GRIDS WILL REFLECT THE HRRR
MODEL THINKING OF WEAK UPRIGHT CONVECTION FORMING NEAR A VORTICITY
CENTER ACROSS SOUTHEASTERN COLORADO. A LOOSELY ORGANIZED CLUSTER OF
CONVECTION COULD DEVELOP A COLD POOL ALLOWING THE CLUSTER OF
CONVECTION TO MOVE INTO THE SOUTHWESTERN QUARTER OR THIRD OF THE DDC
FORECAST AREA (SOUTH AND WEST OF A LAKIN TO MEADE LINE, ROUGHLY).
THE ABSENCE OF APPRECIABLE SURFACE-BASED CAPE IS EXPECTED TO KEEP
CONVECTION BELOW SEVERE LIMITS...BUT SOME GUSTS TO 50 OR 55 MPH WILL
BE POSSIBLE IF LOOSELY ORGANIZED COLD POOLS DEVELOP. ANY STORMS
WHICH IMPACT FAR SOUTHWESTERN KANSAS SHOULD BE EXITING THE AREA BY
LATE EVENING.
ON FRIDAY...WESTERN KANSAS WILL BE UNDER AN INCREASED INFLUENCE OF
NORTHWEST FLOW ALOFT AS THE MID LEVEL SHEAR AXIS CONTINUES TO PUSH
SOUTH INTO TEXAS. THIS IS EXPECTED TO RESULT IN MORE TRANQUIL
SENSIBLE WEATHER. THAT BEING SAID...MID LEVEL TEMPERATURES WILL
STILL BE COOL (700MB TEMPERATURE -2 TO 0C)...AND MIXING
CONDENSATION LEVELS WILL BE LOW AS INSOLATION ALLOWS SURFACE TEMPS
TO WARM INTO THE UPPER 60S. THE RESULT WILL BE DEVELOPMENT OF
CUMULUS AND PERHAPS AN ISOLATED SHOWER OR TO LATE IN THE DAY. THE
OFFICIAL FORECAST WILL BE DRY AS THERE WILL BE AN ABSENCE OF UPPER
LEVEL FORCING FOR ASCENT TO PROMOTE ANY ORGANIZATION OF
CONVECTION.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 335 PM CDT THU MAY 9 2013
THE WEATHER PICTURE THIS WEEKEND WILL DEPICT AN UPPER LEVEL LONG
WAVE TROUGH DIGGING ACROSS THE NORTHEAST UNITED STATES AND AN UPPER
LEVEL RIDGE BUILDING ACROSS THE WESTERN UNITED STATES. MEANWHILE,
THE UPPER LEVEL LOW THAT ASSISTED IN SEVERE STORM DEVELOPMENT ACROSS
OUR AREA THE LAST COUPLE OF NIGHTS WILL SPLIT OFF FROM THE FLOW AND
MIGRATE TOWARDS NORTHERN MEXICO. THESE FEATURES WILL PLACE THE
CENTRAL HIGH PLAINS UNDER NORTHWEST FLOW ALOFT. THIS PATTERN USUALLY
GIVES WAY TO FAIR WEATHER DAYS ACROSS WESTERN KANSAS. HOWEVER, RAIN
CHANCES WILL BE POSSIBLE SATURDAY NIGHT INTO SUNDAY. HIGH PRESSURE
AT THE SURFACE WILL BE THE DOMINATE FEATURE ACROSS WESTERN KANSAS
FRIDAY NIGHT INTO SATURDAY WITH A SECOND AREA OF HIGH PRESSURE
OOZING DOWN FROM THE NORTH SATURDAY NIGHT INTO SUNDAY. A COLD FRONT
WILL BE FOUND IN BETWEEN THESE TWO AREAS OF HIGH PRESSURE ALLOWING
SOME LIFT TO OCCUR ACROSS THE PLAINS SATURDAY NIGHT. THE ATMOSPHERE
WILL BE FAIRLY DRY AS THIS FRONT MOVES THROUGH BUT THERE COULD BE A
SHOWER OR TWO THAT FORMS SATURDAY NIGHT INTO EARLY SUNDAY MORNING.
WINDS WILL GENERALLY BE LIGHT AND VARIABLE FRIDAY NIGHT INTO
SATURDAY SHIFTING TO THE NORTH BEHIND THE FRONT SATURDAY NIGHT INTO
SUNDAY. A WEAK UPPER LEVEL SHORTWAVE IS THEN DEPICTED BY THE MODELS
TO MOVE DOWN THROUGH THE NORTHWEST FLOW AND INTO KANSAS SUNDAY. IF
THIS COMES TO FRUITION, THUNDERSTORM WILL BE POSSIBLE ACROSS CENTRAL
KANSAS SUNDAY MORNING SPREADING TOWARDS SOUTH CENTRAL KANSAS AS THE
DAY PROGRESSES. OTHERWISE PARTLY CLOUDY SKIES WILL BE FOUND ACROSS
WESTERN KANSAS. LEE TROUGHING WILL ALSO BE DEVELOPING ACROSS THE
KS/CO BORDER DURING THIS TIME FRAME SHIFTING WINDS TO MORE OF A
SOUTHERLY DIRECTION. LOWS SATURDAY AND SUNDAY MORNING LOOK TO DIP
INTO THE 40S WITH HIGHS IN THE 70S SATURDAY AND SUNDAY AFTERNOON.
THE UPPER LEVEL RIDGE ACROSS THE WESTERN UNITED STATES WILL THEN
SHIFT EASTWARD INTO THE ROCKIES AND PLAINS DURING THE FIRST PART OF
NEXT WEEK. THIS FEATURE IN CONJUNCTION WITH SURFACE HIGH PRESSURE
LOCATED EAST OF KANSAS WILL BRING MOSTLY CLEAR SKIES AND DRY
CONDITIONS TO WESTERN KANSAS. LEE TROUGHING ACROSS EASTERN COLORADO
WILL CONTINUE AND BRING WARM TEMPERATURES TO THE AREA. HIGHS MONDAY
ARE FORECASTED TO REACH INTO THE 80S WITH HIGHS AROUND 90 DEGREES ON
TUESDAY. LOWS WILL GENERALLY BE IN THE 50S MONDAY AND TUESDAY
MORNING.
MID RANGE MODELS THEN SUGGEST THE UPPER LEVEL LOW ACROSS NORTHERN
MEXICO TO MOVE BACK NORTHEAST TO THE SOUTHERN PLAINS. THIS WOULD
BRING INCREASING CHANCES OF THUNDERSTORMS TO PARTS OF KANSAS MID
WEEK INTO THE FIRST PART OF THE WEEKEND. HIGHS DURING THIS TIME
FRAME WILL GENERALLY BE IN THE 80S.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1243 PM CDT THU MAY 9 2013
A MOIST AIRMASS FROM THE LOWER TO MIDDLE TROPOSPHERE RESULTED IN
WIDESPREAD CLOUD COVER. THERE WERE AREAS OF CEILING IN THE MVFR
RANGE...PARTICULARLY IN THE HAYS AREA. WILL MAINTAIN VFR CEILING
AT THE GCK AND DDC TERMINALS THROUGH THE DAY WITH NORTH/NORTHEAST
WIND STAYING IN THE 12 TO 15 KNOT RANGE. SHOWERS AND ISOLATED WEAK
THUNDERSTORMS ARE EXPECTED TO DEVELOP LATE IN THE AFTERNOON WHICH
COULD AFFECT GCK AND HYS TERMINALS FROM 22Z TO 01Z OR SO THIS
EVENING. OTHERWISE NO ACTIVE WEATHER IS EXPECTED TONIGHT. GIVEN
THE RESIDUAL LOW LEVEL MOISTURE LEFT BEHIND THE WAVE...THERE IS A
MODERATE PROBABILITY OF A FEW HOURS IFR CEILING/VISIBILITY JUST
PRIOR TO DAYBREAK FRIDAY.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 47 68 48 71 / 20 10 10 20
GCK 45 68 47 70 / 30 10 10 20
EHA 48 69 47 71 / 30 10 10 20
LBL 48 70 48 73 / 30 10 10 20
HYS 48 69 48 68 / 20 10 20 20
P28 53 71 50 73 / 20 10 10 20
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...UMSCHEID
SHORT TERM...UMSCHEID
LONG TERM...HOVORKA_42
AVIATION...UMSCHEID
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
223 PM CDT THU MAY 9 2013
...UPDATED SYNOPSIS AND SHORT TERM SECTIONS...
.SYNOPSIS...
ISSUED AT 221 PM CDT THU MAY 9 2013
AN ELONGATED MID LEVEL VORTICITY AXIS WAS FOUND ACROSS THE CENTRAL
PLAINS TODAY COMPLETE WITH MOISTURE AND FAIRLY COOL TEMPERATURES.
UPPER AIR OBSERVATIONS AND RAP ANALYSIS INDICATED 500/700MB
TEMPERATURES AROUND -17C/0C RESPECTIVELY. SOME INSOLATION THROUGH
EARLY AFTERNOON RESULTED IN SURFACE TEMPERATURES WARMING INTO THE
UPPER 60S TO NEAR 70 DEGREES PARTICULARLY SOUTH OF THE ARKANSAS
RIVER. THE MID LEVEL MOISTURE AXIS WAS FOUND TO BE CENTERED FROM THE
CENTRAL ROCKIES THROUGH NORTHERN KANSAS AND MUCH OF NEBRASKA. THIS
LINED UP FAIRLY WELL WITH THE MEAN 500-700MB DEFORMATION AXIS. THE
SURFACE FRONT HAD PUSHED WELL SOUTH OF THE REGION DOWN INTO SOUTHERN
OKLAHOMA, SO SURFACE-BASED INSTABILITY WAS VERY LOW ACROSS
SOUTHWESTERN KANSAS.
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 221 PM CDT THU MAY 9 2013
THE MAIN FORECAST CHALLENGE IS PRECIPITATION CHANCES, COVERAGE, AND
INTENSITY THIS EVENING. THE MENTIONED DEFORMATION AXIS WILL LINGER
ACROSS SOUTHEASTERN COLORADO AND WESTERN KANSAS THROUGH THIS
EVENING. THE UPDATED FORECAST POP/WX GRIDS WILL REFLECT THE HRRR
MODEL THINKING OF WEAK UPRIGHT CONVECTION FORMING NEAR A VORTICITY
CENTER ACROSS SOUTHEASTERN COLORADO. A LOOSELY ORGANIZED CLUSTER OF
CONVECTION COULD DEVELOP A COLD POOL ALLOWING THE CLUSTER OF
CONVECTION TO MOVE INTO THE SOUTHWESTERN QUARTER OR THIRD OF THE DDC
FORECAST AREA (SOUTH AND WEST OF A LAKIN TO MEADE LINE, ROUGHLY).
THE ABSENCE OF APPRECIABLE SURFACE-BASED CAPE IS EXPECTED TO KEEP
CONVECTION BELOW SEVERE LIMITS...BUT SOME GUSTS TO 50 OR 55 MPH WILL
BE POSSIBLE IF LOOSELY ORGANIZED COLD POOLS DEVELOP. ANY STORMS
WHICH IMPACT FAR SOUTHWESTERN KANSAS SHOULD BE EXITING THE AREA BY
LATE EVENING.
ON FRIDAY...WESTERN KANSAS WILL BE UNDER AN INCREASED INFLUENCE OF
NORTHWEST FLOW ALOFT AS THE MID LEVEL SHEAR AXIS CONTINUES TO PUSH
SOUTH INTO TEXAS. THIS IS EXPECTED TO RESULT IN MORE TRANQUIL
SENSIBLE WEATHER. THAT BEING SAID...MID LEVEL TEMPERATURES WILL
STILL BE COOL (700MB TEMPERATURE -2 TO 0C)...AND MIXING
CONDENSATION LEVELS WILL BE LOW AS INSOLATION ALLOWS SURFACE TEMPS
TO WARM INTO THE UPPER 60S. THE RESULT WILL BE DEVELOPMENT OF
CUMULUS AND PERHAPS AN ISOLATED SHOWER OR TO LATE IN THE DAY. THE
OFFICIAL FORECAST WILL BE DRY AS THERE WILL BE AN ABSENCE OF UPPER
LEVEL FORCING FOR ASCENT TO PROMOTE ANY ORGANIZATION OF
CONVECTION.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 315 AM CDT THU MAY 9 2013
ON FRIDAY NIGHT, THERE WILL BE A WEAK SHORT WAVE MOVING THROUGH THE
UPPER LEVEL DOWN SLOPE FLOW. SURFACE FRONTS WILL BE WELL SOUTH OF
SOUTHWESTERN KANSAS, BUT THERE COULD STILL BE ENOUGH MOISTURE IN
THE LOWER LAYERS FOR A FEW SHOWERS AND THUNDERSTORMS TRIGGERED BY
THE ELEVATED WAVE. THERE WILL ONLY BE SLIGHT CHANCES FOR
PRECIPITATION FRIDAY NIGHT, WITH THOSE PRECIPITATION CHANCES
SHIFTING TO THE SOUTHERN COUNTIES ALONG THE OKLAHOMA BORDER
SATURDAY. PRECIPITATION CHANCES WILL INCREASE INTO THE 30 PERCENT
RANGE DOWN SOUTH ALONG THE OKLAHOMA BORDER SATURDAY, WHERE MORE
MOISTURE WILL BE AVAILABLE. BY SUNDAY, THERE COULD BE A WARM
FRONT MOVING NORTH INTO OUR NORTHEAST SECTIONS, FROM APPROXIMATELY
WAKEENEY TO KINSLEY TO COLDWATER, AND BY THE AFTERNOON A FEW
STORMS COULD FIRE NORTHEAST OF THAT LINE. DO NOT EXPECT TO MUCH
RAINFALL WITH THE SUNDAY SYSTEM, AND RIGHT NOW I HAVE MY DOUBTS IF
ANY STORM WILL REACH SEVERE LEVELS. AFTER SUNDAY, THE REST OF THE
EXTENDED FORECAST SHOULD BE DRY, WITH A NORTHWEST FLOW BECOMING
ESTABLISHED OVER KANSAS AND AN UPPER HIGH PRESSURE AREA BUILDING
IN FROM THE WEST. THERE MAY BE A SLIGHT CHANCE FOR STORMS
WEDNESDAY NIGHT INTO THURSDAY, BUT THE ALLBLEND/CONSALL MODELS
KEPT MOST OF THE PRECIPITATION CHANCES NORTH OF OUR AREA FOR
WEDNESDAY INTO THURSDAY.
ON THE TEMPERATURE TRENDS, WE WILL SEE THE FRIDAY, SATURDAY AND
SUNDAY PERIODS FAIRLY SEASONAL, WITH LOWS IN THE MID 40S TO LOWER
50S AND HIGHS MAINLY IN THE 60S AND 70S. THEN ON MONDAY, WE
SHOULD SHIFT INTO A SIGNIFICANT WARMING TREND. MINIMUMS MONDAY
MORNING WILL BE IN THE LOWER TO MID 50S, BUT WILL WARM INTO THE
60S BY WEDNESDAY AND THURSDAY. MAXIMUM TEMPERATURES WILL LEAP
UPWARD ON MONDAY INTO THE MIDDLE TO UPPER 80S NEAR THE COLORADO
BORDER, AND TO THE LOWER 80S FROM HAYS TO LARNED TO MEDICINE
LODGE. FOR NOW, TUESDAY LOOKS TO BE THE WARMEST DAY, WITH FULL
DOWNSLOPE FLOW IN FORCE. ON TUESDAY, PARTS OF OUR WESTERN CWA,
WEST OF A SCOTT CITY TO CIMARRON TO LIBERAL LINE, MAY HAVE MAX
TEMPS PEAK AROUND 90 DEGREES, POSSIBLY THE FIRST 90+ DEGREES FOR A
FEW OF THE LOCATIONS (DDC ALREADY HIT 91 AND LBL 93, BOTH ON APR
30TH. HYS HIT 93 ON APR 28TH.) A FEW MORE CLOUDS WILL ADVECT IN ON
WEDNESDAY, SO I AM EXPECTING SLIGHTLY LOWER MAX TEMPERATURES WED,
MAINLY IN THE MID 80S.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1243 PM CDT THU MAY 9 2013
A MOIST AIRMASS FROM THE LOWER TO MIDDLE TROPOSPHERE RESULTED IN
WIDESPREAD CLOUD COVER. THERE WERE AREAS OF CEILING IN THE MVFR
RANGE...PARTICULARLY IN THE HAYS AREA. WILL MAINTAIN VFR CEILING
AT THE GCK AND DDC TERMINALS THROUGH THE DAY WITH NORTH/NORTHEAST
WIND STAYING IN THE 12 TO 15 KNOT RANGE. SHOWERS AND ISOLATED WEAK
THUNDERSTORMS ARE EXPECTED TO DEVELOP LATE IN THE AFTERNOON WHICH
COULD AFFECT GCK AND HYS TERMINALS FROM 22Z TO 01Z OR SO THIS
EVENING. OTHERWISE NO ACTIVE WEATHER IS EXPECTED TONIGHT. GIVEN
THE RESIDUAL LOW LEVEL MOISTURE LEFT BEHIND THE WAVE...THERE IS A
MODERATE PROBABILITY OF A FEW HOURS IFR CEILING/VISIBILITY JUST
PRIOR TO DAYBREAK FRIDAY.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 47 68 48 71 / 20 10 10 20
GCK 45 68 47 70 / 30 10 10 20
EHA 48 69 47 71 / 30 10 10 20
LBL 48 70 48 73 / 30 10 10 20
HYS 48 69 48 68 / 20 10 20 20
P28 53 71 50 73 / 20 10 10 20
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...UMSCHEID
SHORT TERM...UMSCHEID
LONG TERM...BURKE
AVIATION...UMSCHEID
AREA FORECAST DISCUSSION
NWS PADUCAH KY
809 PM CDT FRI MAY 10 2013
.UPDATE...
ISSUED AT 809 CDT FRI MAY 10 2013
MAIN ADJUSTMENT EARLY THIS EVENING IS THE TIMING/LOCATION OF THE
CURRENT CONVECTIVE ACTIVITY /SHOWERS AND THUNDERSTORMS/...AS WELL
AS THE ATTENDENT WIND AND TEMPERATURE FIELDS BEHIND THE COLD
FRONT. THE 3KM HRRR GUIDANCE...SPATIALLY ADJUSTED...APPEARS TO BE
HANDLING THE STORM SCALE DEVELOPMENT FAIRLY WELL THROUGH MIDNIGHT.
GIVEN THE POST-FRONTAL CLOUD COVER AND LIMITED EROSION OF THIS
CLOUD COVER DUE TO LOW AMPLITUDE COLD AIR ADVECTION...FOG
POTENTIAL SHOULD REMAIN MINIMAL OVER THE WFO PAH FORECAST AREA.
UPDATE ISSUED AT 637 PM CDT FRI MAY 10 2013
UPDATED THE AVIATION SECTION FOR THE 00Z TAF ISSUANCE.
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY NIGHT)
ISSUED AT 258 PM CDT FRI MAY 10 2013
THE COLD FRONT HAS YET TO REALLY PUSH INTO THE FORECAST AREA AS OF
1930Z. A PRE-FRONTAL WIND SHIFT HAS FOCUSED SOME SCATTERED
CONVECTION ON A LINE FROM NEAR KPOF TO KMWA...BUT IT HAS ONLY
GENERATED SPORADIC LIGHTNING. LAPS INDICATES THAT THE MOST
UNSTABLE SURFACE AIRMASS IS OVER FAR SOUTHEAST MISSOURI AND
SOUTHWEST KENTUCKY...SO WOULD EXPECT THAT CONVECTION TO PROGRESS
SOUTHEAST THROUGH 00Z. ANOTHER BAND OF SHOWERS WILL PUSH THROUGH
THE KOWB AREA IN THE NEXT HOUR OR SO.
WILL TAKE THE EASY WAY OUT AND JUST MOVE AN AREA OF LIKELY POPS
SOUTHEAST THROUGH WEST KENTUCKY THROUGH SUNSET...ALTHOUGH WITH THE
VERY SLOW SPEED OF MOVEMENT OF BOUNDARIES AND CONVECTIVE
ELEMENTS...COULD SEE IT FALLING APART BEFORE REACHING THE FAR
SOUTHEAST PORTIONS OF THE FORECAST AREA.
WILL QUICKLY DIMINISH POPS FROM NORTHWEST TO SOUTHEAST THROUGH THE
FIRST PART OF THE EVENING...BUT THE FRONT WILL LAG BEHIND THIS
EVENING...NOT CLEARING THE ENTIRE AREA UNTIL AROUND 06Z.
FOR SATURDAY...THE MODELS HAVE CONTINUED THEIR AGGRESSIVE TREND IN
BRING A BAND OF SHOWERS AND POSSIBLY THUNDERSTORMS THROUGH THE
AREA ALONG A SECONDARY FRONT. THIS FRONT WILL BE QUITE STRONG AND
SHALLOW...SO WOULD EXPECT IT TO MAKE QUICKER PROGRESS THROUGH THE
AREA. HAVE A BAND OF 20-40 POPS MOVING SOUTHWARD THROUGH THE
FORECAST AREA THROUGH THE AFTERNOON. WILL EVEN LINGER A SLIGHT
CHANCE OF SHOWERS OVER WEST KENTUCKY INTO THE EVENING.
GOOD COLD...DRY ADVECTION IS EXPECTED SATURDAY NIGHT AND
SUNDAY. THE SURFACE HIGH WILL SETTLE OVER THE SUNDAY NIGHT...WHICH
WILL RESULT IN EXCELLENT RADIATIONAL COOLING CONDITIONS. THE
MODELS ARE TRENDING COLDER SUNDAY NIGHT...AND THE CONSENSUS TAKES
DEWPOINTS INTO THE LOWER AND MIDDLE 30S. SO.......LOWS IN THE 30S
AND AT LEAST SOME PATCHY FROST SEEM TO BE LIKELY FOR MUCH OF THE
AREA. HAVE LOOKED AT IT FOR 5 DAYS NOW AND THIS IS BY FAR THE
COOLEST THE MODELS HAVE GONE. HAVE LITTLE REASON TO NOT BELIEVE
IT AT THIS POINT.
.LONG TERM...(MONDAY THROUGH FRIDAY)
ISSUED AT 258 PM CDT FRI MAY 10 2013
HIGH PRESSURE WILL USHER IN A MUCH COOLER AND DRIER AIR MASS SUNDAY.
WE EXPECT LOWS AROUND 40 BOTH SUNDAY AND MONDAY MORNINGS WITH MONDAY
THE COOLEST...SECOND DAY AFTER FRONTAL PASSAGE IS USUALLY THE
COOLEST AS A RULE OF THUMB. PATCHY FROST CAN NOT BE RULED OUT AT
THIS TIME BUT WITH CURRENT PROJECTIONS WOULD BE VERY LIMITED AND NOT
WIDESPREAD. HOWEVER WILL MONITOR CLOSELY FOR ANY REVISIONS.
SOUTHERLY FLOW RETURNS ON THE BACKSIDE OF THE HIGH NEXT WEEK WHICH
WILL BEGIN A WARMING TREND. MODELS ARE IN GOOD AGREEMENT THE NEXT
STORM SYSTEM WILL DEVELOP OVER SW US AND DRIVE NE ACROSS THE
PLAINS...REACHING THE HEARTLAND LATE IN THE WEEK. THE LAST COUPLE
GFS RUNS TRY TO PHASE THIS A COLD FRONT APPROACHING FROM THE
NORTH...HOWEVER THE ECMWF STALLS THE FRONT TO THE NORTH AND BRINGS
THE LOW IN A LITTLE SLOWER BUT PAINTS QPF OVER THE AREA AS WELL JUST
A LITTLE LATER. FOR NOW PLAN TO LEAN TOWARD THE SLOWER ECMWF AND
HOLD PRECIP OFF UNTIL POSSIBLY THURSDAY AND MAY END UP HOLDING UNTIL
THURSDAY NIGHT AS THAT SYSTEM BECOMES CLOSER WITH TIME. HOWEVER WILL
WAIT AND SEE WHAT THE EXTENDED INIT PRODUCES AND COLLABORATE WITH
SURROUNDING OFFICES FOR THE BEST FIT OR TIME FRAME FOR NEXT WEEKS
STORM SYSTEM.
&&
.AVIATION...
ISSUED AT 637 PM CDT FRI MAY 10 2013
EARLY IN THE PERIOD VFR CONDITIONS EXPECTED AT ALL SITES...WITH THE
EXCEPTION OF MVFR CONDITIONS IN SHRA/TSRA AT KPAH/KOWB THROUGH
02Z...AFT 03-04Z MVFR CIGS EXPECTED THROUGH 14-15Z...THEN VFR.
WESTERLY WINDS AOB 10 KTS WILL VEER AROUND TO THE NORTHWEST AFT
03Z.
&&
.PAH WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
MO...NONE.
IN...NONE.
KY...NONE.
&&
$$
UPDATE...SMITH
AVIATION...JP
AREA FORECAST DISCUSSION...UPDATED
NWS PADUCAH KY
1135 PM CDT WED MAY 8 2013
.UPDATE...
ISSUED AT 1130 PM CDT WED MAY 8 2013
UPDATED THE AVIATION SECTION FOR THE 06Z TAF ISSUANCE.
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY NIGHT)
ISSUED AT 300 PM CDT WED MAY 8 2013
THE LATEST AVAILABLE HRRR OUTPUT DEVELOPS AT LEAST SCATTERED
CONVECTION AHEAD OF THE MCV MOVING OVER CENTRAL MISSOURI. STARTING
TO SEE SOME ENHANCEMENT ON VISIBILTY SATELLITE IMAGERY AND SOME
SHOWER DEVELOPMENT TO OUR WEST/NORTHWEST ON RADAR. DECIDED TO
INCREASE POPS UP TO LOWER CHANCE LEVELS COMING OUT OF THE OZARK
FOOTHILLS THROUGH SUNSET. THE HRRR DISSIPATES THE STRONGER
ELEMENTS AS THEY APROACH THE MISSISSIPPI RIVER AROUND 02Z.
FOLLOWED THE HRRR CLOSELY INTO THE EVENING...AND WILL HAVE A DRY
FORECAST BY 03Z. ISOLATED SHOWERS AND THUNDERSTORMS OVER SOUTHWEST
INDIANA AND THE PENNYRILE THIS AFTERNOON SHOULD DISSIPATE OR MOVE
SOUTH/EAST OF THE AREA BY SUNSET.
THE 12Z MODELS ARE TRENDING DRIER FOR LATER TONIGHT AND ESPECIALLY
THURSDAY. SOUNDINGS INDICATE THAT A WEAK CAP WILL BE SUFFICIENT TO
KEEP MOST AREAS DRY...DUE TO A GENERAL LACK OF DEEP MOISTURE OR
MAJOR FORCING. WILL SPREAD GOOD CHANCE POPS EASTWARD ALONG THE
I-64 CORRIDOR THROUGH THE MORNING AND KEEP THEM AT THAT LEVEL THERE
THROUGH THE AFTERNOON AND INTO THE EVENING. THIS AREA WILL BE
CLOSEST TO ANY EFFECTS OF MID/UPPER LEVEL DISTURBANCES AND THE
FRONT ITSELF. WOULD BE VERY SURPRISED TO SEE ANYTHING MORE THAN A
VERY ISOLATED STORM PULSE UP TO NEAR SEVERE LEVELS ALONG I-64
THURSDAY AFTERNOON. WILL KEEP SLIGHT CHANCES TO THE SOUTH JUST IN
CASE WE DESTABILIZE ENOUGH FOR A PARCEL TO BREAK THROUGH DURING
THE AFTERNOON.
THURSDAY WILL SEE INCREASING CHANCES OF SHOWERS AND
THUNDERSTORMS...AS THE COLD FRONT AND IMPACTS OF THE PRIMARY
MID/UPPER LEVEL DISTURBANCE APPROACH THE AREA. THE LLJ WILL
INCREASE TO AROUND 35KTS...WHICH SHOULD HELP TO BRING SOME
BETTER...DEEPER MOISTURE NORTHEAST ACROSS MUCH OF THE AREA. WILL
HAVE A SOUTHWEST TO NORTHEAST BAND OF LIKELY POPS OVER SOUTHEAST
MISSOURI AND SOUTHERN ILLINOIS LATE IN THE EVENING...AND THEN MOVE
IT SLOWLY EASTWARD ACROSS THE REMAINDER OF THE AREA OVERNIGHT.
THE MODELS SEEM TO HAVE CONVERGED FOR FRIDAY. A WEAK COLD FRONT
WILL SLOWLY PUSH EASTWARD ACROSS THE AREA THROUGH THE DAY AND
SHOULD CLEAR THE ENTIRE AREA BY EARLY EVENING. WITH THE FRONT AND
THE MAIN MID/UPPER DISTURBANCE OVER THE AREA FRIDAY...LIKELY POPS
SEEM WARRANTED...WITH AN EMPHASIS OVER WEST KENTUCKY. A LACK OF
FORCING...ONLY WEAK INSTABILITY...AND GENERALLY WEAK WIND PROFILES
SHOULD KEEP ANY CONVECTION WELL BELOW SEVERE LIMITS. SOME VERY
LOCALIZED HEAVY RAINFALL SHOULD BE THE PRIMARY CONCERN FRIDAY.
POPS WILL LINGER INTO FRIDAY EVENING...MAINLY IN THE EAST...BUT
THE MODEL CONSENSUS IS FOR THE ENTIRE AREA TO BE DRY BY 06Z SATURDAY.
AS FOR TEMPERATURES...WENT ON HIGH END OF GUIDANCE FOR HIGHS
THURSDAY...AND TOWARD THE COOL SIDE FRIDAY. WENT A BIT ABOVE
GUIDANCE FOR LOWS FRIDAY NIGHT. OTHERWISE...CONSENSUS OF GUIDANCE
SHOULD BE FINE.
.LONG TERM...(SATURDAY THROUGH WEDNESDAY)
ISSUED AT 300 PM CDT WED MAY 8 2013
OVER THE WEEKEND...A CLOSED LOW OVER ONTARIO AT THE START OF THE
PERIOD...MOVES EAST AND ENDS UP CARVING A DEEP TROUGH OVER THE GREAT
LAKES AND DOWN INTO OUR REGION. A SECONDARY FRONT MOVES SOUTH TOWARD
US ON SATURDAY AND WHILE IT SEEMS TO START OUT WITH ENOUGH MOISTURE
TO OUR NORTH...BY THE TIME THE FRONT GETS HERE SATURDAY
EVENING...NOT MUCH MOISTURE IS LEFT. SO OPTED TO REMOVE ALL POPS FOR
SATURDAY.
BEHIND THE SECONDARY COLD FRONT...MUCH COOLER AIR WILL FILTER INTO
THE AREA SATURDAY NIGHT AND INTO SUNDAY...ON THE NOSE OF SFC HIGH
PRESSURE FROM CANADA. THE 00Z/12Z ECMWF AND 06Z/12Z GFS INDICATE
850MB TEMPS AT OR BELOW ZERO IN OUR FAR NORTHERN COUNTIES.
HOWEVER...SINCE HIGH PRESSURE WILL STILL BE MOVING IN...THE WIND
WILL LIKELY STAY UP WHICH WILL PREVENT US FROM DROPPING TOO LOW ON
OUR LOW TEMPS FOR SATURDAY NIGHT.
THE SFC HIGH WILL FINALLY BEGIN TO SETTLE OVER THE AREA ON SUNDAY
AND SUNDAY NIGHT...WITH ALL INDICATIONS THAT THE CENTER OF THE HIGH
WILL BE DIRECTLY OVER US ON 12Z MONDAY. WITH COLD AIR ADVECTION IN
FULL SWING ON SUNDAY...WOULD VENTURE TO GUESS WE WILL NOT GET OUT OF
THE 60S FOR HIGHS. THE COLDEST AIR WILL BE SITUATED OVER OUR
NORTHEASTERN COUNTIES (NAMELY SE IL...SWIN...PENNYRILE). LOOKING AT
CIPS ANALOG DATA ALONG WITH RECORDS FROM XMACIS...WE COULD BE
LOOKING AT LOWS SUNDAY NIGHT FALLING INTO THE UPPER 30S FOR THESE
PORTIONS OF OUR AREA IF THE GFS IS CORRECT. 850 MB TEMPS OFF THE GFS
AND THE GFS ENSEMBLE MEAN ARE A BIT COOLER THAN THE ECMWF...AND WITH
CALM WINDS AND CLEAR SKIES...WE COULD DROP QUITE A BIT. LOOKING AT
RAW MODEL DEWPOINT TEMPS...THIS ALSO SUPPORTS THESE COOLER
TEMPS...WHICH COULD GET CLOSE TO TYING RECORDS IN THE EVV AREA.
ELSEWHERE THOUGH...IT STILL LOOKS COOL WITH LOWS IN THE LOWER 40S.
AGAIN...THIS MAY BE COLD ENOUGH TO SUPPORT THE FORMATION OF VERY
PATCHY FROST IN OUTLYING AREAS...BUT A WIDESPREAD FROST IS STILL NOT
ANTICIPATED ATTM.
THE SFC HIGH MOVES EAST AND EVENTUALLY SOUTH ON MONDAY/MONDAY NIGHT AND
THAT IS WHEN THE WARM UP WILL BEGIN. DEPENDING ON HOW LOW WE START
THE DAY WITH ON MONDAY...WE WILL STILL BE COOL WITH HIGHS REMAINING
IN THE 60S/POSSIBLY AROUND 70 FAR WEST. THE FLOW IN THE LOW LEVELS
BECOMES SOUTHERLY/SOUTHWESTERLY LATE MONDAY NIGHT INTO TUESDAY AND
850 MB TEMPS WILL RISE STEADILY FROM THEN THROUGH THE END OF THE
EXTENDED PERIOD (WEDNESDAY). THEREFORE...WE EXPECT HIGHS IN THE 70S
ON TUESDAY WITH AROUND 80 ON WEDNESDAY. THIS EARLY WEEK PERIOD
CONTINUES TO BE DRY. LOOKING BEYOND THAT...MODELS TRY TO BRING A
FRONT INTO THE AREA BUT DIFFER ON TIMING.
&&
.AVIATION...
ISSUED AT 1130 PM CDT WED MAY 8 2013
VFR CONDITIONS EXPECTED AT ALL SITES THROUGH THE PERIOD. CHANCE
OF VCTS AT ALL SITES STARTING AT 00Z. VARIABLE WINDS AOB 5 KTS
WILL PICK UP OUT OF THE SOUTH AT 10-15KTS WITH GUSTS OF 15-24 KTS
AFT 15Z...THEN DIMINISH TO AOB 10 KTS AFT 00Z.
&&
.PAH WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
MO...NONE.
IN...NONE.
KY...NONE.
&&
$$
AVIATION...JP
PUBLIC...DB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
136 AM EDT THU MAY 9 2013
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 408 PM EDT WED MAY 8 2013
WATER VAPOR IMAGERY AND RUC ANALYSIS STILL SHOW BLOCKY FLOW
DOMINATING THE CONUS TO THE S OF PROGRESSIVE BUT GRADUALLY
AMPLIFYING FLOW ACROSS CANADA. IN THE BLOCKY CONUS FLOW...MID LEVEL
LOWS ARE LOCATED OVER THE SOUTHERN ROCKIES...ERN SD AND THE MID
ATLANTIC STATES. TO THE N...FLOW ACROSS CANADA HAS AMPLIFIED SOME IN
THE LAST COUPLE OF DAYS AS TROFFING IS NOSING S THRU MANITOBA/NRN
ONTARIO. MUCH STRONGER AMPLIFICATION WILL FOLLOW THIS WEEKEND AS
SHARP TROFFING DEVELOPS S INTO THE GREAT LAKES. COLD FRONT
ASSOCIATED WITH SHORTWAVE THAT MOVED FROM MANITOBA YESTERDAY TO
QUEBEC TODAY IS JUST NW AND N OF LAKE SUPERIOR. AHEAD OF THE
FRONT...IT HAS BEEN ANOTHER WARM DAY ACROSS UPPER MI. SOME LOCATIONS
ALONG LAKE SUPERIOR HAVE EXPERIENCED A MUCH WARMER DAY TODAY AS LAKE
BREEZE DID NOT DEVELOP AS EARLY AS IN PREVIOUS DAYS...AND IT IS
WEAKER. DESPITE ONSHORE WINDS ALONG LAKE MI...COOLING THERE HAS ONCE
AGAIN BEEN WEAK. INLAND...TEMPS HAVE SOARED THRU THE 70S WITH A FEW
SPOTS REACHING 80F. VERY DRY AIR STILL LINGERS OVER A GOOD PORTION
OF UPPER MI (NOTE THE VERY DRY COLUMN AGAIN SAMPLED BY THE 12Z KGRB
SOUNDING). AS A RESULT...DWPTS HAVE CRASHED DOWN AS LOW AS THE UPPER
20S/LWR 30S ACROSS PORTIONS OF MAINLY CNTRL/ERN UPPER MI. RH IS IN
THE 15-25PCT RANGE AT MOST LOCATIONS. FORTUNATELY...WINDS REMAIN
LIGHT...KEEPING FIRE WX CONCERNS IN CHECK FROM WHERE THEY COULD BE
ON A DAY LIKE THIS. SOME OF THE MID LEVEL MOISTURE NOTED ON PREVIOUS
DAYS SOUNDINGS FROM KINL/KMPX HAS ADVECTED INTO UPPER MI TODAY AND
MADE ITS PRESENCE KNOWN WITH POCKETS OF SCT/BKN MID CLOUDS EARLIER
IN THE DAY. DAYTIME HEATING HAS NOW LED TO VERY HIGH BASED CU
DEVELOPING OVER MUCH OF UPPER MI. A FEW RADAR RETURNS HAVE APPEARED
ON KMQT RADAR IMAGERY OVER WRN UPPER MI...BUT DRY LOW-LEVEL AIR HAS
PROBABLY PREVENTED ANY PCPN OR AT LEAST NOTHING MORE THAN A FEW
SPRINKLES FROM REACHING THE GROUND.
COLD FRONT TO THE N WILL DROP S...PASSING ACROSS UPPER MI
TONIGHT/EARLY THU MORNING. LOW-LEVEL DRY AIR WILL CONTINUE TO BE A
PROBLEM DUE TO LITTLE ADVECTION OF ANY MOISTURE AT THE LOW-LEVELS.
EVEN UPSTREAM...KINL/KMPX SOUNDINGS SHOW THAT LOW-LEVELS THERE HAVE
BEEN DRYING OUT OVER THE LAST DAY OR TWO...BUT THERE IS STILL
SUFFICIENT MOISTURE FOR SCT SHRA AND EVEN A FEW TSRA OVER NRN MN
INTO NW WI THIS AFTN. AS MID LEVEL LOW OVER ERN SD DRIFTS E...IT MAY
HELP PUSH BETTER MOISTURE INTO THE FRONTAL BOUNDARY THAT IS DROPPING
OVER THE AREA. HOWEVER...GIVEN THE LOW-LEVEL WIND FLOW/LACK OF
MOISTURE ADVECTION...PREFER THE GEM/ECMWF/UKMET AND TO SOME DEGREE
THE NAM IDEA OF MAINTAINING THE LOW-LEVEL DRY AIR OVER THE AREA
TONIGHT. AS A RESULT...WILL ONLY INCLUDE SCHC/LOW CHC POPS OVER THE
NW PORTION OF THE FCST AREA.
WITH MID LEVEL LOW OPENING UP/WEAKENING AS IT TRACKS E THU...IT
PROBABLY WON`T BE ABLE TO BRING A GOOD PUSH OF MOISTURE N OF THE
COLD FRONT THAT PASSED THRU THE AREA. HOWEVER...THERE ARE
INDICATIONS THAT MID LEVEL FGEN WILL INCREASE ACROSS THE UPPER
LAKES. WITH COLD FRONT SLIPPING S OF THE FCST AREA IN THE
MORNING...THERE WILL BE A BETTER OPPORTUNITY FOR LOW-LEVELS TO
MOISTEN IN THE COOLER AIR MASS UNDERNEATH THE FGEN FORCING...AND
THIS SHOULD PROVIDE AT LEAST A CHANCE OF SHRA OVER MUCH OF THE AREA
THU. WILL PAINT MAINLY THE WRN FCST AREA FOR BEST CHC OF SHRA AS
THERE ARE HINTS OF LOW-LEVEL DRY AIR STILL LINGERING OVER THE E.
WITH CAA AND MORE CLOUDS...IT WILL BE A COOLER DAY...ESPECIALLY NEAR
LAKE SUPERIOR DUE TO GRADIENT FLOW ACROSS THE LAKE (TEMPS ALONG THE
LAKE WILL PROBABLY ONLY BE IN THE LOW/MID 40S THRU THE DAY). ACROSS
THE SCNTRL AND E...TEMPS MAY STILL REACH THE MID 60S.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 408 PM EDT WED MAY 8 2013
UPPER FLOW GOES THROUGH A TRANSITION DURING THE LONG TERM PERIOD.
INITIALLY ON THURSDAY NIGHT FLOW IS MORE ZONAL WITH BROAD SHALLOW
TROUGH OVER MOST OF CANADA. LATER FRIDAY TRHOUGH SATURDAY...EXPECT
SHARP AMPLIFICATION AS TROUGH CURRENTLY NORTH OF ALASKA BARRELS
ACROSS CANADIAN PRAIRIES AND ONTARIO. PRIMARY COLD FRONT SWINGS
ACROSS UPPER MICHIGAN FRIDAY NIGHT INTO SATURDAY MORNING WITH
PARENT SFC LOW REACHING CENTRAL QUEBEC BY SUNDAY MORNING. MODELS
HAVE TRENDED FARTHER EAST WITH UPPER LOW CENTER AND QUICKER WITH
FRONTAL PASSAGE. TROUGH ALOFT SLOWLY MOVES INTO EASTERN CANADA ON
MONDAY WITH STRONG RIDGE AND WARM AIR EXPANDING TOWARD CENTRAL
CANADA AND THE PLAINS. TAIL END OF EXTENDED FEATURES WARMING TREND
OVER UPPER LAKES AS RIDGING MOVES FARTHER EAST. MAY SEE BREEZY
CONDITIONS ACCOMPANYING THE WARM UP AS STRONG LOW PRESSURE MOVES
FROM MANITOBA TO NORTHWEST ONTARIO.
SHALLOW COOL AIR SLOWLY FILTERS ACROSS UPR MICHIGAN LATER THURSDAY
AND THURSDAY EVENING. STILL A POTENTIAL OF RAIN THURSDAY EVENING
WITH LINGERING H7-H5 MOISTURE/LIFT DUE TO H7-H6 FRONTOGENESIS. NAM
AND GFS MORE BULLISH ON QPF OVER CWA COMPARED TO ECMWF AND GEM-NH.
THINKING NAM IDEA IS TOO FAR WEST WITH PRECIPITATION BAND...BUT
WILL KEEP SMALL POPS OVER SOUTH AND EAST THROUGH 03Z FRIDAY. REST
OF THURSDAY NIGHT INTO FRIDAY LOOKING QUIET OUT AHEAD OF THE STRONG
COLD FRONT. ONE CONCERN COULD BE STRONGER EAST-NORTHEAST WINDS OVER
EASTERN CWA THURSDAY NIGHT INTO FRIDAY MORNING...ESPECIALLY IF NOT
MUCH RAIN OCCURS THERE AND HUMIDITY RECOVERIES ARE POOR THURSDAY
NIGHT. GRADIENT WINDS DIMINISH THROUGH THE DAY ON FRIDAY...BUT AS
BUBBLE HIGH AT 1025MB BUILDS OVER LK SUPERIOR...NORTH WINDS COULD
STAY GUSTY INTO MID AFTN FROM COPPER HARBOR TO MARQUETTE AND GRAND
MARAIS. VERY DRY CONDITIONS AS H85 DWPNTS ARE DOWN TO AROUND -30C.
GIVEN SUCH DRY AIRMASS...EXPECT MIXED LAYER DWPNTS TO MIX OUT AWAY
FROM IMMEDIATE LK SUPERIOR SHORE AS LOW AS MID-UPPER TEENS IN THE
AFTN. EVEN WITH MUCH COOLER TEMPERATURES...ONLY AS WARM AS THE UPPER
50S INLAND...LOW DWPNTS WILL RESULT IN HUMIDITY VALUES BLO 25 PCT
IN AFTERNOON. BASED ON SOUNDINGS...DRY AIRMASS HANGS ON THROUGH
FRIDAY EVENING OVER ALL CWA.
FOCUS THEN IS ON STRONG COLD FRONTAL PASSAGE BY SATURDAY. 1000-500MB
THICKNESS PACKING FROM ECMWF/GFS/NAM INDICATE FRONTAL PASSAGE AFTER
MIDNIGHT FRIDAY NIGHT OVER FAR WEST CWA AND EARLY SATURDAY AFTERNOON
OVER THE FAR EASTERN CWA. SOUNDINGS SHOW MOISTURE BUILDING DOWN FROM
MID-LEVELS...RESULTING IN ONLY A FEW HOURS OF SATURATION FOR SOME
SHOWERS BEFORE DRYING AND SUBSIDENCE KICK IN BEFORE DAYBREAK OVER
WESTERN CWA AND BY MID MORNING OVER EASTERN CWA. WITH THE INITIAL
BATCH OF SHOWERS...LOOKS LIKE IT REMAINS TOO WARM BLO H9 TO HAVE
SNOW MIX IN WITH THE RAIN. 06Z NAM SHOWED ENOUGH COLD AIR WORKING
IN JUST AS PRECIP ENDED AT ERY FOR SOME SNOW SATURDAY MORNING. 12Z
RUN KEEPS IT ALL LIQUID. UNCERTAIN HOW MUCH MOISTURE IS AROUND ON
SATURDAY...BUT THAT WILL HAVE BEARING ON HOW MUCH PRECIP OCCURS AND
WHETHER THERE WILL BE ANY SNOW OR MIXED RAIN AND SNOW. THINKING THAT
NAM MAY BE OVERDONE WITH EXTENT OF SUBSIDENCE/DRYING OR AT THE LEAST
THE EXTENT/DURATION OF DRYING ON SATURDAY. GFS/ECMWF POINT TO CHANCE
OF MORE DIURNAL/COLD POOL TYPE SHOWERS AS TOTAL TOTALS PUSH 50 AND
WITH INCREASING H85-H7 RH. SHOULD SEE LOTS OF CLOUDS AND WILL GO
WITH LOW CHANCES FOR SHOWERS MOST AREAS. GIVEN ENOUGH MOISTURE AS
GFS/ECMWF INDICATE...WET BULB BLO ZERO THROUGH THE DEPTH OF THE
COLUMN WOULD SUPPORT AT LEAST A MIX OF RAIN AND SNOW OVER THE WEST
HALF. MAX TEMPS IN UPPER 30S TO LOWER 40S AT THE COOLEST WILL NOT
ALLOW FOR ANY APPRECIABLE SNOW ACCUMS THOUGH THERE COULD BE BRIEF
REDUCED VSBY IN THE HEAVIEST SNOW SHOWERS. OTHER ISSUE ON SATURDAY
WILL BE STRONG/GUSTY WINDS. SOUNDINGS INDICATE UNIDIRECTIONAL WNW
30-40 KT MIXED LAYER WINDS. PORTION OF THESE WINDS WILL MIX DOWN IN
GUSTS DUE TO MECHANICAL MIXING AND COLD AIR ADVECTION. EXPECT
STRONGEST WINDS OVER 40 MPH ON THE KEWEENAW PENINSULA...WITH GUSTS
OVER 30 MPH ELSEWHERE.
DRYING TREND TAKES OVER SUNDAY INTO MONDAY AS THE LARGER SCALE
TROUGH DEPARTS THE AREA. STILL COOL FOR SUNDAY WITH SIMILAR
READINGS TO SATURDAY. QUITE CHILLY SUNDAY NIGHT WITH MANY AREAS
FALLING BLO FREEZING WITH PWAT LESS THAN 50 PCT OF NORMAL AS SFC
HIGH PRESSURE RIDGE MOVES ACROSS.
REST OF EXTENDED FEATURES WARMING TREND AS RIDGE OVER PLAINS BUILDS
ACROSS. ELEVATED MOISTURE AND INSTABILITY WITH THE WARM AIR ADVECTION
MAY TRIGGER SCT SHOWERS/TSRA TUESDAY. CHANCES FOR WIDESPREAD PRECIP
SEEM LOW THOUGH AS PRIMARY LARGE SCALE LIFT STAYS OVER ONTARIO.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 132 AM EDT THU MAY 9 2013
EXPECT VFR CONDITIONS THROUGH EARLY THU MORNING AT KIWD/KCMX/KSAW AS
LOW-LEVELS REMAIN VERY DRY. THU MORNING...STRENGTHENING CHILLY N/NE
FLOW AND INCREASING POTENTIAL OF -SHRA MAY RESULT IN A LOW
STRATOCU/STRATUS DECK DEVELOPING AT ALL THE SITES WITH MVFR CIGS
DEVELOPING. UPSLOPE COMPONENT AT IWD AND SAW WILL KEEP THE CIGS IN
THROUGH EARLY THU EVENING EXCEPT AT SAW WHERE THE MOIST UPSLOPE NE
FLOW WILL KEEP THE MVFR CIG IN THROUGH THU EVENING. AT CMX...DRY
AIR WILL COME BACK IN LATE THU AFTERNOON AND CONDITIONS WILL GO BACK
TO VFR.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 408 PM EDT WED MAY 8 2013
LIGHT WINDS WILL PERSIST INTO THE EVENING. THEN...FOLLOWING THE
PASSAGE OF A COLD FRONT TONIGHT...NNE WINDS WILL INCREASE UP TO
15-25KT LATE TONIGHT THRU THU NIGHT. THE ARRIVAL OF ANOTHER HIGH
PRES RIDGE WILL THEN CAUSE WINDS TO DIMINISH FRI. A STRONGER COLD
FRONT WILL SLIDE ACROSS THE UPPER LAKES FRI NIGHT AND SHIFT WINDS TO
THE NW AT 20-30KT FOR SAT. GIVEN TIGHT PRES GRADIENT AND STRENGTH OF
CAA...GALE FORCE GUSTS WILL LIKELY OCCUR. WINDS WILL THEN DIMINISH W
TO E SUN AS HIGH PRES RIDGE ARRIVES. WINDS SHOULD BE UNDER 15KT
LATER SUN NIGHT THRU MON.
&&
.HYDROLOGY...
ISSUED AT 408 PM EDT WED MAY 8 2013
WARM TEMPS CONTINUE TO MELT LINGERING SN PACK OVER THE HIER TERRAIN
OF THE W AND NCENTRAL. RUNOFF INTO THE MONTREAL RIVER AND ISOLD
FLOODING ALONG THE WISCONSIN AND MICHIGAN BORDER IN WESTERN GOGEBIC
COUNTY NEAR IRONWOOD PROMPTED EVENING SHIFT ON TUESDAY TO ISSUE
AREAL FLOOD ADVISORY FOR GOGEBIC COUNTY. THIS MATCHES UP WITH FLOOD
ADVISORY OUT FOR IRON COUNTY WISCONSIN ISSUED BY WFO DULUTH. PLAN TO
LET WFO MARQUETTE ADVY EXPIRE AS SCHEDULED AS NO OTHER FLOODING HAS
BEEN REPORTED.
OTHERWISE...MOST AREA STREAMS/RIVERS CONTINUE TO REMAIN STEADY OR
SHOW SLOW DECLINE WITH RECENT DRY WX. WITH MINIMAL PRECIP IN THE
FORECAST IN THE COMING DAYS AND BULK OF SNOW PACK GONE EXCEPT OVER
THE HIGHER TERRAIN OF THE KEWEENAW/NCENTRAL...SUSPECT THESE TRENDS
WILL CONTINUE. RIVER ADVISORIES OR FLOOD WARNINGS CONTINUE FOR THE
TRAP ROCK RIVER AT LAKE LINDEN...THE STURGEON RIVER AT ALSTON AND
CHASSELL...AND THE MICHIGAMME RIVER AT WITCH LAKE AND REPUBLIC. FOR
COMPLETE DETAILS...SEE THE LATEST PRODCUTS FOR THESE RIVER FLOOD
WARNINGS AND ADVISORIES.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...ROLFSON
LONG TERM...JLA
AVIATION...07
MARINE...ROLFSON
HYDROLOGY...JLA
AREA FORECAST DISCUSSION...UPDATED
NWS ST LOUIS MO
906 PM CDT FRI MAY 10 2013
.UPDATE...
ISSUED AT 905 PM CDT FRI MAY 10 2013
BACK EDGE OF LOW CLOUD DECK IS CURRENTLY NEAR A VERSAILLES...
BOONEVILLE...MOUNT PLEASANT IOWA LINE. EXTRAPOLATION SUGGESTS A
SE MOVEMENT OF 15-20KTS...A BIT FASTER THAN EARLIER EXPECTED.
SO...THIS UPDATE CLEAR SKIES A BIT MORE RAPIDLY...WITH A
CORRESPONDING DIP IN MIN TEMPS ESPECIALLY OVER THE NW HALF OF THE
CWA. WILL CARRY DRIZZLE FOR A FEW MORE HOURS IN OUR S
COUNTIES...PRIMARILY S AND SE OF STL.
TRUETT
&&
.SHORT TERM...(TONIGHT THROUGH SATURDAY)
ISSUED AT 328 PM CDT FRI MAY 10 2013
THE FIRST SHOT OF COOLER AIR HAS OVERSPREAD THE AREA WITH THE
ASSOCIATED COLD FRONT NOW ACROSS EXTREME SOUTHEAST MISSOURI AND
SOUTHERN ILLINOIS. EXTENSIVE STRATUS BLANKETS MUCH OF THE AREA AND
EXTENDS WELL NORTH INTO EASTERN IOWA AT MID AFTERNOON. THE MODELS
VARY ON HOW QUICKLY TO CLEAR THE LOW CLOUDS...AND I HAVE SIDED
WITH THE SLOWER RUC AND LOCAL WRF WITH SLOW CLEARING FROM NORTH TO
SOUTH TONIGHT...AND THE SOUTHEAST CWA NOT CLEARING UNTIL AFTER
DAYBREAK ON SATURDAY. A SERIES OF POWERFUL SHORT WAVES NOW ACROSS
MANITOBA AND SASKATCHEWAN WILL DIG SOUTHEASTWARD TONIGHT WITH A
CLOSED LOW EVOLVING. THIS UPPER LOW/TROF WILL CONTINUE TO DEEPEN
WITH A BROAD DEEP LONGWAVE TROF EVOLVING ACROSS THE EASTERN CONUS
BY SATURDAY NIGHT. INTIALLY IN THE PROCESS...THE DIGGING TROF
WILL DRIVE A COLD FRONT ACROSS THE AREA ON SATURDAY. THIS FRONT
WILL USHER A MORE POTENT BLAST OF CHILLY AIR INTO THE REGION ON
THE ORDER OF 2-3 STANDARD DEVIATIONS BELOW NORMAL. IT STILL LOOKS
LIKE THERE WILL BE A CHANCE OF SHOWERS AND EVEN SOME THUNDERSTORMS
FORMING ALONG THE FRONT AS IT MOVES QUICKLY SOUTHEASTWARD. THE
FORCING APPEARS TO BE LARGELY FRONTAL AND THIS SUGGESTS SCATTERED
COVERAGE. INSTABILITY WILL BE WEAK...PROBABLY OVERDONE ON THE NAM
OWING TO TOO HIGH SURFACE DEW POINTS...BUT STILL GREAT ENOUGH TO
SUPPORT A THUNDER THREAT. IT WILL BE A NARROW 1-2 HOUR WINDOW FOR
PRECIPITATION OCCURING WITH THE FRONT AND THEN GUSTY NW WINDS IT
ITS WAKE.
GLASS
.LONG TERM...(SATURDAY NIGHT THROUGH NEXT FRIDAY)
ISSUED AT 328 PM CDT FRI MAY 10 2013
THE DEEP LONGWAVE TROF WILL DOMINATE THE PATTERN AND CONTROL THE
SENSIBLE WEATHER SATURDAY NIGHT INTO EARLY MONDAY WITH A COOL
SURFACE HIGH PREVAILING. BELOW AVERAGE TEMPERATURES WILL BE THE
RULE AND SOME RECORDS COULD BE APPROACHED ON SUNDAY MORNING. THERE
COULD ALSO BE SOME PATCHY FROST WHERE LOWS DIP INTO THE MID 30S.
THE SURFACE HIGH MOVE ACROSS THE AREA ON SUNDAY AND GRADUALLY
RETREAT SOUTHEAST SUNDAY NIGHT INTO THE WESTERN TN VALLEY. THIS
SUGGESTS THAT THE COOLEST TEMPERATURES ON SUNDAY NIGHT AND MONDAY
MORNING WILL BE ACROSS THE EASTERN OZARKS AND SW ILLINOIS WHERE
LOWS IN THE MID-UPPER 30S AND PATCHY FROST WILL ONCE AGAIN BE
POSSIBLE. LOW LEVEL WAA WILL THEN COMMENCE ON MONDAY AND THIS
SHOULD LEAD TO A NICE REBOUND IN TEMPERATURES AS THE LOWER
TROPOSPHERIC FLOW BECOMES MORE SOUTHERLY.
SAY GOODBYE TO THE COOL...I THINK FOR GOOD...BY TUESDAY. THE LONGWAVE
TROF DEPARTS OFF THE EAST COAST AND HEIGHTS RISE ALOFT AS A SHORT
WAVE RIDGE BUILDS INTO THE MS VALLEY. STRONG WAA WILL PROGRESS AND
H85 TEMPS ARE FORECAST TO RISE ABOVE +18 DEGC ON ALL THE GUIDANCE...
SUPPORTING HIGHS WELL INTO THE 80S. MOISTURE AND CLOUDS WILL BEGIN
TO INCREASE LATE WEDNESDAY AS A NEW UPSTREAM TROF MOVES ACROSS THE
PLAINS AND EVENTUALLY INTO THE MS VALLEY BY THURSDAY. THE MODELS
DISAGREE ON WHETHER AN EAST-WEST FRONT WILL ALSO DROP INTO THE
AREA DURING THIS TIME...BUT THE PRESENCE OF THE UPPER TROF ALONE
SUPPORTS A CHANCE OF SHOWERS AND THUNDERSTORMS DURING THE LATER
PART OF THE WEEK.
GLASS
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 700 PM CDT FRI MAY 10 2013
MVFR CONDITIONS TO PREVAIL THROUGH 06Z-09Z TIMEFRAME...BEFORE
CLOUDS SCATTER OUT AND WINDS BECOME LIGHT AND VARIABLE. SECONDARY
FRONTAL BOUNDARY TO SLIDE THROUGH FORECAST AREA ON
SATURDAY...MOVING THROUGH KUIN BY 14Z...KCOU BY 15Z AND METRO AREA
BY 17Z. SOME DECENT CAPES/INSTABILITY WITH BOUNDARY...SO SHOULD
SEE SHOWERS AND A FEW THUNDERSTORMS. BUT TIMING AND COVERAGE HARD
TO PIN DOWN...SO JUST KEPT VCNTY SHOWER MENTION/VFR CIGS IN FOR NOW.
OTHERWISE...WINDS TO PICKUP BEHIND THE FRONT FROM THE NORTHWEST
WITH GUSTS NEAR 25KTS AT TIMES.
SPECIFICS FOR KSTL...MVFR CONDITIONS TO PREVAIL THROUGH 09Z
SATURDAY...BEFORE CLOUDS SCATTER OUT AND WINDS BECOME LIGHT AND
VARIABLE. SECONDARY FRONTAL BOUNDARY TO SLIDE THROUGH METRO
AREA BY 17Z SATURDAY. SOME DECENT CAPES/INSTABILITY WITH BOUNDARY...SO
SHOULD SEE SHOWERS AND A FEW THUNDERSTORMS. BUT TIMING AND
COVERAGE HARD TO PIN DOWN...SO JUST KEPT VCNTY SHOWER MENTION/VFR
CIGS IN FOR NOW. OTHERWISE...WINDS TO PICKUP BEHIND THE FRONT FROM
THE NORTHWEST WITH GUSTS NEAR 25KTS AT TIMES. WINDS TO DIMINISH
AND CLOUDS CLEAR OUT BY EARLY SATURDAY EVENING.
BYRD
&&
.CLIMATE...
ISSUED AT 328 PM CDT FRI MAY 10 2013
RECORD LOWS
5/125/13
ST LOUIS39 (1960)40 (1971)
COLUMBIA35 (1892)34 (1901)
QUINCY35 (1960)35 (1971)
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
700 PM CDT FRI MAY 10 2013
.SHORT TERM...(TONIGHT THROUGH SATURDAY)
ISSUED AT 328 PM CDT FRI MAY 10 2013
THE FIRST SHOT OF COOLER AIR HAS OVERSPREAD THE AREA WITH THE
ASSOCIATED COLD FRONT NOW ACROSS EXTREME SOUTHEAST MISSOURI AND
SOUTHERN ILLINOIS. EXTENSIVE STRATUS BLANKETS MUCH OF THE AREA AND
EXTENDS WELL NORTH INTO EASTERN IOWA AT MID AFTERNOON. THE MODELS
VARY ON HOW QUICKLY TO CLEAR THE LOW CLOUDS...AND I HAVE SIDED
WITH THE SLOWER RUC AND LOCAL WRF WITH SLOW CLEARING FROM NORTH TO
SOUTH TONIGHT...AND THE SOUTHEAST CWA NOT CLEARING UNTIL AFTER
DAYBREAK ON SATURDAY. A SERIES OF POWERFUL SHORT WAVES NOW ACROSS
MANITOBA AND SASKATCHEWAN WILL DIG SOUTHEASTWARD TONIGHT WITH A
CLOSED LOW EVOLVING. THIS UPPER LOW/TROF WILL CONTINUE TO DEEPEN
WITH A BROAD DEEP LONGWAVE TROF EVOLVING ACROSS THE EASTERN CONUS
BY SATURDAY NIGHT. INTIALLY IN THE PROCESS...THE DIGGING TROF
WILL DRIVE A COLD FRONT ACROSS THE AREA ON SATURDAY. THIS FRONT
WILL USHER A MORE POTENT BLAST OF CHILLY AIR INTO THE REGION ON
THE ORDER OF 2-3 STANDARD DEVIATIONS BELOW NORMAL. IT STILL LOOKS
LIKE THERE WILL BE A CHANCE OF SHOWERS AND EVEN SOME THUNDERSTORMS
FORMING ALONG THE FRONT AS IT MOVES QUICKLY SOUTHEASTWARD. THE
FORCING APPEARS TO BE LARGELY FRONTAL AND THIS SUGGESTS SCATTERED
COVERAGE. INSTABILITY WILL BE WEAK...PROBABLY OVERDONE ON THE NAM
OWING TO TOO HIGH SURFACE DEW POINTS...BUT STILL GREAT ENOUGH TO
SUPPORT A THUNDER THREAT. IT WILL BE A NARROW 1-2 HOUR WINDOW FOR
PRECIPITATION OCCURING WITH THE FRONT AND THEN GUSTY NW WINDS IT
ITS WAKE.
GLASS
.LONG TERM...(SATURDAY NIGHT THROUGH NEXT FRIDAY)
ISSUED AT 328 PM CDT FRI MAY 10 2013
THE DEEP LONGWAVE TROF WILL DOMINATE THE PATTERN AND CONTROL THE
SENSIBLE WEATHER SATURDAY NIGHT INTO EARLY MONDAY WITH A COOL
SURFACE HIGH PREVAILING. BELOW AVERAGE TEMPERATURES WILL BE THE
RULE AND SOME RECORDS COULD BE APPROACHED ON SUNDAY MORNING. THERE
COULD ALSO BE SOME PATCHY FROST WHERE LOWS DIP INTO THE MID 30S.
THE SURFACE HIGH MOVE ACROSS THE AREA ON SUNDAY AND GRADUALLY
RETREAT SOUTHEAST SUNDAY NIGHT INTO THE WESTERN TN VALLEY. THIS
SUGGESTS THAT THE COOLEST TEMPERATURES ON SUNDAY NIGHT AND MONDAY
MORNING WILL BE ACROSS THE EASTERN OZARKS AND SW ILLINOIS WHERE
LOWS IN THE MID-UPPER 30S AND PATCHY FROST WILL ONCE AGAIN BE
POSSIBLE. LOW LEVEL WAA WILL THEN COMMENCE ON MONDAY AND THIS
SHOULD LEAD TO A NICE REBOUND IN TEMPERATURES AS THE LOWER
TROPOSPHERIC FLOW BECOMES MORE SOUTHERLY.
SAY GOODBYE TO THE COOL...I THINK FOR GOOD...BY TUESDAY. THE LONGWAVE
TROF DEPARTS OFF THE EAST COAST AND HEIGHTS RISE ALOFT AS A SHORT
WAVE RIDGE BUILDS INTO THE MS VALLEY. STRONG WAA WILL PROGRESS AND
H85 TEMPS ARE FORECAST TO RISE ABOVE +18 DEGC ON ALL THE GUIDANCE...
SUPPORTING HIGHS WELL INTO THE 80S. MOISTURE AND CLOUDS WILL BEGIN
TO INCREASE LATE WEDNESDAY AS A NEW UPSTREAM TROF MOVES ACROSS THE
PLAINS AND EVENTUALLY INTO THE MS VALLEY BY THURSDAY. THE MODELS
DISAGREE ON WHETHER AN EAST-WEST FRONT WILL ALSO DROP INTO THE
AREA DURING THIS TIME...BUT THE PRESENCE OF THE UPPER TROF ALONE
SUPPORTS A CHANCE OF SHOWERS AND THUNDERSTORMS DURING THE LATER
PART OF THE WEEK.
GLASS
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 700 PM CDT FRI MAY 10 2013
MVFR CONDITIONS TO PREVAIL THROUGH 06Z-09Z TIMEFRAME...BEFORE
CLOUDS SCATTER OUT AND WINDS BECOME LIGHT AND VARIABLE. SECONDARY
FRONTAL BOUNDARY TO SLIDE THROUGH FORECAST AREA ON
SATURDAY...MOVING THROUGH KUIN BY 14Z...KCOU BY 15Z AND METRO AREA
BY 17Z. SOME DECENT CAPES/INSTABILITY WITH BOUNDARY...SO SHOULD
SEE SHOWERS AND A FEW THUNDERSTORMS. BUT TIMING AND COVERAGE HARD
TO PIN DOWN...SO JUST KEPT VCNTY SHOWER MENTION/VFR CIGS IN FOR NOW.
OTHERWISE...WINDS TO PICKUP BEHIND THE FRONT FROM THE NORTHWEST
WITH GUSTS NEAR 25KTS AT TIMES.
SPECIFICS FOR KSTL...MVFR CONDITIONS TO PREVAIL THROUGH 09Z
SATURDAY...BEFORE CLOUDS SCATTER OUT AND WINDS BECOME LIGHT AND
VARIABLE. SECONDARY FRONTAL BOUNDARY TO SLIDE THROUGH METRO
AREA BY 17Z SATURDAY. SOME DECENT CAPES/INSTABILITY WITH BOUNDARY...SO
SHOULD SEE SHOWERS AND A FEW THUNDERSTORMS. BUT TIMING AND
COVERAGE HARD TO PIN DOWN...SO JUST KEPT VCNTY SHOWER MENTION/VFR
CIGS IN FOR NOW. OTHERWISE...WINDS TO PICKUP BEHIND THE FRONT FROM
THE NORTHWEST WITH GUSTS NEAR 25KTS AT TIMES. WINDS TO DIMINISH
AND CLOUDS CLEAR OUT BY EARLY SATURDAY EVENING.
BYRD
&&
.CLIMATE...
ISSUED AT 328 PM CDT FRI MAY 10 2013
RECORD LOWS
5/125/13
ST LOUIS39 (1960)40 (1971)
COLUMBIA35 (1892)34 (1901)
QUINCY35 (1960)35 (1971)
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
1212 PM CDT Thu May 9 2013
.SHORT TERM...(Today through Saturday Afternoon)
Issued at 350 AM CDT THU MAY 9 2013
Conditions remain quiet early this morning as strong isentropic
lift and a veered LLJ have driven showers and thunderstorms into far
northeastern Missouri and southern Iowa. Regional radar and WV
imagery depict several developed MCV this morning, one located over
north central Kansas with two additional waves over northern and
eastern Oklahoma.
Through daybreak, short term guidance is in agreement that most of
the area will remain quiet as the vort max over north central Kansas
tracks northeast through the northwestern corner of Missouri. Have
lowered PoPs in most locations through daybreak. The stronger
southern MCV is now beginning to turn to the east as it enters
eastern Oklahoma. HRRR/RAP have struggled with this second wave, but
feel it will track into southern Missouri and gradually turn northeast
towards St. Louis after daybreak, perhaps tracking a little further
south than HRRR suggests.
Today: Subsidence in the wake of the MCV will prevent much in the
way of activity during the morning hours, and we may actually see
clouds scatter by late morning as a stationary boundary remains
draped over eastern Kansas and the northwestern third of Missouri.
Soundings indicate very low convective temperatures today, and by
late morning, we may already be approaching 70 in many areas.
Subsidence behind the departing wave will only last so long, as
stronger upper troughing remains over western Kansas. MLCAPE values
only approach 800-1000 J/KG, and shear remains marginal, thus only
anticipating a few small hail producing storms. The degree of heating
in the southeastern zones remains more questionable given the track
of the southern KS MCV this morning. Additional cloud cover and
stronger subsidence behind this wave in central Missouri may prevent
widespread redevelopment.
Thursday night-Friday: Surface troughing will push southeast
Thursday evening as upper troughing to the west begins to pivot
eastward and colder air aloft spills southward. Weak mid-level
frontogenesis may produce some lingering showers through the
overnight hours of Thursday. A north wind will prevail on Friday as
the front continues to push into southeastern Missouri and the upper
trough pivots overhead. Have lowered high temperatures a few degrees
due to the cloudy conditions and cold air advection aloft.
Temperatures may need to be lowered further in some areas.
Saturday: Weak surface ridging will slide through the area Friday
night before a much stronger cold front arrives on Saturday. Winds
will quickly turn northwest by late Saturday afternoon, turning
blustery. Temperatures will struggle to reach the lower 60s.
.LONG TERM...(Saturday Evening through Wednesday)
Issued at 350 AM CDT THU MAY 9 2013
Sunday - Tuesday:
This period will be characterized by dry weather an a marked warming
trend. Canadian high pressure will settle over the area by Sunday
morning making for a very cool start to the day. We will even flirt
with record lows (record low at MCI is 39 set in 1997). By Sunday
afternoon 850mb temps are only 2-6C which will yield highs only in
the upper 50s to lower 60s. On Monday upper level ridging that was
over the western Rockies on Sunday will begin to shift eastward into
the eastern Rockies and western Plains. This will provide for height
rises across the area. Couple that with surface high pressure
pushing off to the southeast and allowing for a return to southerly
flow and highs will rise into the upper 60s to mid 70s. By Tuesday
the upper level ridge axis moves over head. 850mb temperatures will
rise to 16-20C. And, with strong southwesterly winds providing for
good mixing, highs will be some of the warmest we have experienced
this season with highs in the low to mid 80s.
Wednesday:
Wednesday the upper level ridge will be shunted to the southeast as
an upper level trough digs into the Upper Midwest. This will send a
weak cold front into the area which will provide the next chance of
showers and thunderstorms. There is some question as to how much
moisture this system will have as the EC has a surface high pressure
over the Gulf Coast states keeping the Gulf closed. The GFS has high
pressure over the eastern Gulf with the western Gulf open and
moisture being transported into the area. Have maintained chance
POPs inherited by the initialization to account for the GFS solution.
&&
.AVIATION...(For the 18Z TAFS through 18Z Friday Afternoon)
Issued at 1212 PM CDT THU MAY 9 2013
Lower ceilings across northwestern Missouri and northern Kansas
should stay north of the Kansas City terminals through tonight. MVFR
ceilings are already occurring at STJ and these should remain in
place. Ceilings will drop to fuel-alternate MVFR levels tonight as a
cold front slides south. Winds will also switch to the north behind
the front but will still remain light. Timing of when MVFR ceilings
may lift is questionable at this point but have lifted them out of
fuel-alternate state late in the valid period, though they will still
likely be MVFR.
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
MO...NONE.
&&
$$
SHORT TERM...31
LONG TERM...73
AVIATION...CDB
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
640 AM CDT Thu May 9 2013
.SHORT TERM...(Today through Saturday Afternoon)
Issued at 350 AM CDT THU MAY 9 2013
Conditions remain quiet early this morning as strong isentropic
lift and a veered LLJ have driven showers and thunderstorms into far
northeastern Missouri and southern Iowa. Regional radar and WV
imagery depict several developed MCV this morning, one located over
north central Kansas with two additional waves over northern and
eastern Oklahoma.
Through daybreak, short term guidance is in agreement that most of
the area will remain quiet as the vort max over north central Kansas
tracks northeast through the northwestern corner of Missouri. Have
lowered PoPs in most locations through daybreak. The stronger
southern MCV is now beginning to turn to the east as it enters
eastern Oklahoma. HRRR/RAP have struggled with this second wave, but
feel it will track into southern Missouri and gradually turn northeast
towards St. Louis after daybreak, perhaps tracking a little further
south than HRRR suggests.
Today: Subsidence in the wake of the MCV will prevent much in the
way of activity during the morning hours, and we may actually see
clouds scatter by late morning as a stationary boundary remains
draped over eastern Kansas and the northwestern third of Missouri.
Soundings indicate very low convective temperatures today, and by
late morning, we may already be approaching 70 in many areas.
Subsidence behind the departing wave will only last so long, as
stronger upper troughing remains over western Kansas. MLCAPE values
only approach 800-1000 J/KG, and shear remains marginal, thus only
anticipating a few small hail producing storms. The degree of heating
in the southeastern zones remains more questionable given the track
of the southern KS MCV this morning. Additional cloud cover and
stronger subsidence behind this wave in central Missouri may prevent
widespread redevelopment.
Thursday night-Friday: Surface troughing will push southeast
Thursday evening as upper troughing to the west begins to pivot
eastward and colder air aloft spills southward. Weak mid-level
frontogenesis may produce some lingering showers through the
overnight hours of Thursday. A north wind will prevail on Friday as
the front continues to push into southeastern Missouri and the upper
trough pivots overhead. Have lowered high temperatures a few degrees
due to the cloudy conditions and cold air advection aloft.
Temperatures may need to be lowered further in some areas.
Saturday: Weak surface ridging will slide through the area Friday
night before a much stronger cold front arrives on Saturday. Winds
will quickly turn northwest by late Saturday afternoon, turning
blustery. Temperatures will struggle to reach the lower 60s.
.LONG TERM...(Saturday Evening through Wednesday)
Issued at 350 AM CDT THU MAY 9 2013
Sunday - Tuesday:
This period will be characterized by dry weather an a marked warming
trend. Canadian high pressure will settle over the area by Sunday
morning making for a very cool start to the day. We will even flirt
with record lows (record low at MCI is 39 set in 1997). By Sunday
afternoon 850mb temps are only 2-6C which will yield highs only in
the upper 50s to lower 60s. On Monday upper level ridging that was
over the western Rockies on Sunday will begin to shift eastward into
the eastern Rockies and western Plains. This will provide for height
rises across the area. Couple that with surface high pressure
pushing off to the southeast and allowing for a return to southerly
flow and highs will rise into the upper 60s to mid 70s. By Tuesday
the upper level ridge axis moves over head. 850mb temperatures will
rise to 16-20C. And, with strong southwesterly winds providing for
good mixing, highs will be some of the warmest we have experienced
this season with highs in the low to mid 80s.
Wednesday:
Wednesday the upper level ridge will be shunted to the southeast as
an upper level trough digs into the Upper Midwest. This will send a
weak cold front into the area which will provide the next chance of
showers and thunderstorms. There is some question as to how much
moisture this system will have as the EC has a surface high pressure
over the Gulf Coast states keeping the Gulf closed. The GFS has high
pressure over the eastern Gulf with the western Gulf open and
moisture being transported into the area. Have maintained chance
POPs inherited by the initialization to account for the GFS solution.
&&
.AVIATION...(For the 12Z TAFS through 12Z Friday Morning)
Issued at 629 AM CDT THU MAY 9 2013
Scattered showers will linger this morning, as weak MCV rotates
through northwestern Missouri. Light winds at KMCI have allowed for a
slightly visibility restriction that will only last for an hour or
two.
Otherwise, VFR conditions will prevail for much of the daytime hours
as frontal boundary remains to the northwest of the major terminals.
As temperatures quickly warm later this morning, scattered showers
and thunderstorms may redevelop, however it will be nearly impossible
to pinpoint the timing and location of these storms in relation to
the terminals. Thus, will leave VCSH through the afternoon and
advertise thunder threat with a CB.
Dux
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
MO...NONE.
&&
$$
SHORT TERM...31
LONG TERM...73
AVIATION...Dux
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
357 AM CDT Thu May 9 2013
.SHORT TERM...(Today through Saturday Afternoon)
Issued at 350 AM CDT THU MAY 9 2013
Conditions remain quiet early this morning as strong isentropic
lift and a veered LLJ have driven showers and thunderstorms into far
northeastern Missouri and southern Iowa. Regional radar and WV
imagery depict several developed MCV this morning, one located over
north central Kansas with two additional waves over northern and
eastern Oklahoma.
Through daybreak, short term guidance is in agreement that most of
the area will remain quiet as the vort max over north central Kansas
tracks northeast through the northwestern corner of Missouri. Have
lowered PoPs in most locations through daybreak. The stronger
southern MCV is now beginning to turn to the east as it enters
eastern Oklahoma. HRRR/RAP have struggled with this second wave, but
feel it will track into southern Missouri and gradually turn northeast
towards St. Louis after daybreak, perhaps tracking a little further
south than HRRR suggests.
Today: Subsidence in the wake of the MCV will prevent much in the
way of activity during the morning hours, and we may actually see
clouds scatter by late morning as a stationary boundary remains
draped over eastern Kansas and the northwestern third of Missouri.
Soundings indicate very low convective temperatures today, and by
late morning, we may already be approaching 70 in many areas.
Subsidence behind the departing wave will only last so long, as
stronger upper troughing remains over western Kansas. MLCAPE values
only approach 800-1000 J/KG, and shear remains marginal, thus only
anticipating a few small hail producing storms. The degree of heating
in the southeastern zones remains more questionable given the track
of the southern KS MCV this morning. Additional cloud cover and
stronger subsidence behind this wave in central Missouri may prevent
widespread redevelopment.
Thursday night-Friday: Surface troughing will push southeast
Thursday evening as upper troughing to the west begins to pivot
eastward and colder air aloft spills southward. Weak mid-level
frontogenesis may produce some lingering showers through the
overnight hours of Thursday. A north wind will prevail on Friday as
the front continues to push into southeastern Missouri and the upper
trough pivots overhead. Have lowered high temperatures a few degrees
due to the cloudy conditions and cold air advection aloft.
Temperatures may need to be lowered further in some areas.
Saturday: Weak surface ridging will slide through the area Friday
night before a much stronger cold front arrives on Saturday. Winds
will quickly turn northwest by late Saturday afternoon, turning
blustery. Temperatures will struggle to reach the lower 60s.
.LONG TERM...(Saturday Evening through Wednesday)
Issued at 350 AM CDT THU MAY 9 2013
Sunday - Tuesday:
This period will be characterized by dry weather an a marked warming
trend. Canadian high pressure will settle over the area by Sunday
morning making for a very cool start to the day. We will even flirt
with record lows (record low at MCI is 39 set in 1997). By Sunday
afternoon 850mb temps are only 2-6C which will yield highs only in
the upper 50s to lower 60s. On Monday upper level ridging that was
over the western Rockies on Sunday will begin to shift eastward into
the eastern Rockies and western Plains. This will provide for height
rises across the area. Couple that with surface high pressure
pushing off to the southeast and allowing for a return to southerly
flow and highs will rise into the upper 60s to mid 70s. By Tuesday
the upper level ridge axis moves over head. 850mb temperatures will
rise to 16-20C. And, with strong southwesterly winds providing for
good mixing, highs will be some of the warmest we have experienced
this season with highs in the low to mid 80s.
Wednesday:
Wednesday the upper level ridge will be shunted to the southeast as
an upper level trough digs into the Upper Midwest. This will send a
weak cold front into the area which will provide the next chance of
showers and thunderstorms. There is some question as to how much
moisture this system will have as the EC has a surface high pressure
over the Gulf Coast states keeping the Gulf closed. The GFS has high
pressure over the eastern Gulf with the western Gulf open and
moisture being transported into the area. Have maintained chance
POPs inherited by the initialization to account for the GFS solution.
&&
.AVIATION...(For the 06Z TAFS through 06Z Thursday Night)
Issued at 1212 AM CDT THU MAY 9 2013
Going to be an active night with periods of showers and
thunderstorms through mid Thursday morning. However, ceilings will
remain in the low end VFR range for the most part. Could have a very
brief period of MVFR ceilings with any heavier cell. The convective
complex that will affect the terminals overnight should move out by
mid/late morning and bring an end to most of the rain. There will
likely still be isolated to scattered lingering showers into the
afternoon hours.
A weak cold front will finally slide southeast through the terminals
during the afternoon and early evening hours. Could see MVFR ceilings
be drawn into the terminals within the post frontal airmass with
scattered showers also a possibility.
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
MO...NONE.
&&
$$
SHORT TERM...31
LONG TERM...73
AVIATION...MJ
AREA FORECAST DISCUSSION
NWS HASTINGS NE
342 PM CDT THU MAY 9 2013
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 330 PM CDT THU MAY 9 2013
A FEW LIGHT SHOWERS WILL CONTINUE TO WRAP AROUND THE
SURFACE LOW ACROSS THE MIDDLE MISSISSIPPI RIVER VALLEY THROUGH THE
LATE AFTERNOON HOURS...AS IT CONTINUES TO TRANSITION FURTHER
EASTWARD. STILL CANNOT RULE OUT THE SLIGHT POSSIBILITY OF A
THUNDERSTORM OR TWO...MAINLY ACROSS PORTIONS OF NORTH CENTRAL
KANSAS...AS MESO ANALYSIS PAGE FROM SPC IS INDICATION SOME WEAK
INSTABILITY PERSISTING ACROSS THIS AREA. LATEST WRF ACTUALLY
HANGS ONTO SOME SCATTERED SHOWER ACTIVITY THROUGH THE OVERNIGHT
HOURS...BUT THIS MODEL SEEMS TO BE THE OUTLIER...SO HAVE NO MORE
THAN A FEW SPRINKLES IN THE FORECAST AFTER 00Z.
THEREAFTER...EXPECT A SURFACE RIDGE OF HIGH PRESSURE TO SLIDE
ACROSS THE FORECAST AREA FROM THE WEST OVERNIGHT...AND WITH THE
ANTICIPATED LIGHT WINDS...PARTIAL CLEARING...AND ELEVATED DEW
POINTS...EXPECT SOME FOG DEVELOPMENT OVERNIGHT. LATEST HRRR IS
HINTING AT DENSE FOG FORMING ALONG THE SPINE OF THE RIDGE AXIS
AFTER MIDNIGHT...BUT WITH SOME UNCERTAINTY STILL...ONLY REDUCED
VISIBILITIES TO 1 MILE ACROSS THE FORECAST AREA DURING THE LATE
OVERNIGHT HOURS THROUGH EARLY FRIDAY MORNING...AND HELD OFF ON
ISSUING A DENSE FOG ADVISORY FOR THE TIME BEING.
AFTER THE FOG BURNS OFF FRIDAY MORNING...EXPECT A FAIRLY NICE AND
SEASONAL DAY ACROSS THE REGION...AS THE SURFACE RIDGE WILL BE SLOW
TO PUSH EAST RESULTING IN GENERALLY LIGHT WINDS DURING THE
AFTERNOON HOURS. WITH CLEARING SKIES...RECOVERING TEMPERATURES
ALOFT...AND GOOD MIXING ANTICIPATED...EXPECT TEMPERATURES TO
RETURN TO NEAR CLIMATOLOGICAL NORMS...GENERALLY IN THE LOWER 70S
AT MOST LOCATIONS.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 330 PM CDT THU MAY 9 2013
REALLY NO SIGNIFICANT CHANGES FOR THE FIRST PORTION OF THE LONG TERM
PERIOD...FRIDAY NIGHT THROUGH THE DAY SATURDAY. MODELS REMAIN IN
PRETTY GOOD AGREEMENT WITH THE OVERALL PATTERN...SHOWING FRIDAY
EVENING UNDER SHARP NORTHWESTERLY FLOW...A RESULT OF A TROUGH AXIS
PUSHING EAST OF THE CWA...AND RIDGING POKING INTO THE CENTRAL/NRN
WEST COAST...NORTH OF CUT OFF LOW OVER THE NM/AZ/MEX BORDER AREA.
FOCUS TURNS TO AN UPPER LEVEL LOW PRESSURE SYSTEM OVER CENTRAL
CANADA...WHICH IS EXPECTED TO SLIDE SOUTHEAST OVERNIGHT AND BY
SATURDAY MORNING IS REACHING INTO THE WRN GREAT LAKES AREA. THE
ACCOMPANYING TROUGH AXIS WILL EXTEND TO THE SOUTH AND SWING THROUGH
THE CENTRAL PLAINS PRIMARILY FRIDAY NIGHT...AND KEPT THE MENTION OF
SPRINKLES GOING ACROSS THE NRN HALF OF THE CWA. WITH THE BRUNT OF
THE LIFT WELL NE OF THE CWA...AND FORECAST SOUNDINGS CONTINUING TO
SHOW DRIER AIR IN THE AREA...DIDNT WANT TO INSERT ANY MEASURABLE
PRECIP AT THIS POINT. THE TIMING OF THE SFC COLD FRONT PUSHED
THROUGH THE CWA BY THIS DISTURBANCE HASNT CHANGED MUCH WITH THE
LATEST MODEL RUNS...AND BY 12Z SATURDAY LOOKS TO HAVE PUSHED THROUGH
TO AT LEAST THE NE/KS STATE LINE...AND EVEN A LITTLE FURTHER SOUTH
VIA THE NAM/SREF. THROUGH THE DAYTIME HOURS ON SATURDAY...SHOULD
SEE DECREASING CLOUD COVER...AND EXPECTING WINDS TO BE ON THE GUSTY
SIDE THROUGH AT LEAST THE FIRST HALF OF THE DAY...BUT SHOULD
DIMINISH ESP BY LATE AFTERNOON AS SFC HIGH PRESSURE BUILDS IN FROM
THE NORTH. THE COOLER AIRMASS ACCOMPANYING THIS FRONT IS EXPECTED
TO BRING A DROP IN HIGHS...BUT STILL EXPECTING TO REACH INTO THE
60S.
FOR SATURDAY NIGHT AND SUNDAY...MAIN CHANGE MADE TO THIS TIME FRAME
WAS TO ADD POPS TO THE FORECAST. YESTERDAY THERE WAS JUST A HINT AT
THE POSSIBILITY OF THE ACTIVITY DEVELOPING ALONG THE HIGH PLAINS
/DRIVEN BY UPSLOPE FLOW AND A WEAK MID LEVEL DISTURBANCE/ SATURDAY
AFTERNOON SLIDING SOUTHEAST AND AFFECTING AT LEAST PORTIONS OF THE
CWA...BUT NOW THE 12Z RUNS OF THE OPERATIONAL MODELS HAVE TRENDED
THIS WAY. ADDED SOME SLIGHT CHANCE AND CHANCE POPS FOR NOW...STILL
SOME SLIGHT VARIATIONS WITH TIMING/LOCATIONS...BUT MOST DO SHOW
ACTIVITY LINGERING INTO THE 12-18Z PERIOD SUNDAY. INSTABILITY IS
PRETTY PATHETIC...MUCAPE VALUES OF ARND 100 J/KG...SO WHILE AN
ISOLATED RUMBLE OF THUNDER OR TWO ARE POSSIBLE...NOT EXPECTING
WIDESPREAD THUNDERSTORMS. DEPENDING ON THE SPEED THIS ACTIVITY
EXISTS...THE HIGHS FOR THE DAY MAY NEED SOME ADJUSTMENT. TRENDED
HIGHS BACK JUST A DEGREE OR TWO OVERALL...BUT IF THINGS LINGER
LONGER THAN CURRENTLY EXPECTED...TEMPS WILL LIKELY STRUGGLE TO REACH
WHAT IS FORECAST /MID 60S TO NEAR 70/.
MONDAY AND TUESDAY...HERE COMES THE WARM UP. PAST FEW RUNS OF THE
MODELS HAVE BEEN PRETTY CONSISTENT WITH THE PATTERN ACROSS THE
CONUS...AT 12Z MONDAY THE CWA IS STILL SITTING UNDER NORTHWESTERLY
FLOW...AS THE CUT OFF LOW CONTINUES TO SIT OVER NRN MEX...AND
RIDGING ORIGINATING OFF THE WEST COAST IS EXTENDED INTO THE
ROCKIES. BY THE END OF THE DAYTIME HRS ON MONDAY AXIS LOOKS TO HAVE
SHIFTED FURTHER EAST INTO THE ROCKIES. WARMER AIR ACCOMPANYING THIS
RIDGE WILL BRING A BUMP UP IN TEMPS MONDAY...AND AGAIN TUESDAY AS
THE CWA REMAINS UNDER ITS INFLUENCE. HIGHS ON MONDAY CURRENTLY
FORECAST TO REACH THE UPPER 70S TO MID 80S...WITH TUESDAY LOOKING AT
MID 80S TO NEAR 90 DEGREES.
A LITTLE MORE UNCERTAINTY IN THE FORECAST ARISES FOR WEDNESDAY AND
THURSDAY...WITH THE POTENTIAL FOR PRECIP RETURNING. THE UPPER LEVEL
RIDGE LOOKS TO BECOME BROKEN DOWN...FROM BOTH THE LOW WHICH HAD BEEN
SET UP OVER MEX SHIFTING EAST INTO THE PLAINS...AND ADDITIONAL
ENERGY SLIDING IN FROM THE PAC NW. PLENTY OF THINGS TO IRON OUT IN
THE COMING DAYS...BUT AT THIS POINT KEPT POPS CONFINED TO THE
WED/THURS DAYTIME PERIOD...HOWEVER HAVE NO DOUBT THE TIMING WILL BE
ADJUSTED. THESE DISTURBANCES LOOK TO BRING THE POTENTIAL FOR SFC
FRONTS MOVING INTO THE AREA...WITH A SLIGHT DECREASE IN TEMPS...WITH
HIGHS BOTH DAYS CURRENTLY IN THE MID 70S TO LOWER 80S.
&&
.AVIATION...(FOR THE 18Z KGRI TAF THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1245 PM CDT THU MAY 9 2013
MVFR STRATUS EXPECTED TO LINGER NEAR THE TERMINAL THROUGH THE
AFTERNOON HOURS AS MOISTURE CONTINUES TO WRAP AROUND THE SURFACE
LOW ACROSS IOWA/MISSOURI THIS AFTERNOON. MAY EVEN SEE A FEW LIGHT
SHOWERS PASS ACROSS THE TERMINAL FROM TIME TO TIME...BUT COVERED
THIS WITH A VCSH FOR THE TIME BEING AS NO SIGNIFICANT IMPACTS ARE
EXPECTED IF ANY SHOWERS DO BRUSH THE TERMINAL. EXPECT ANY SHOWER
ACTIVITY THAT DOES DEVELOP TO DIMINISH AND PUSH SOUTH BY
SUNSET...WITH SOME PARTIAL CLEARING COMBINED WITH LIGHTER WINDS TO
CONTRIBUTE TO DEVELOPMENT OF SOME BR/FG AFTER MIDNIGHT. WHILE SOME
OF THE GUIDANCE TAKING VISIBILITIES BELOW 1 MILE
OVERNIGHT...INTRODUCED ONLY IFR CIGS/VSBYS AROUND DAYBREAK WHEN
ANY FOG THAT DOES DEVELOP WILL BE THE THICKEST.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...SAR
LONG TERM...ADO
AVIATION...SAR
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
1148 PM CDT WED MAY 8 2013
.AVIATION...06Z TAFS FOR KOFK...KLNK AND KOMA.
SHORT TERM AVN CONCERNS STILL ARE STILL ISOLD -TSRA ALONG AND
SOUTH OF I-80...THUS AFFECTING KOMA AND KLNK. EXPECT CELLS TO DIE
OFF THOUGH OVER THE COUPLE HOURS. HOWEVER...TSRA WILL INCREASE IN
AREAL COVERAGE ALONG THE NEB/KS BORDER THRU TONIGHT. DO NOT
BELIEVE THAT ACTIVITY WILL MAKE MUCH OF A PUSH NWD...THUS SPARING
KOMA/KLNK FROM ANY FURTHER STORMS. NEXT ISSUE IS DETERIORATING
CONDITIONS REST OF TONIGHT. LATEST OBS SHOWING MVFR COND
BEGINNING TO SETTLE IN OVER ERN NEB...AND EXPECT TREND TO CONTINUE.
WITH INFLUX OF LLVL MOISTURE...EXPECT MVFR/IFR CONDITIONS WILL
PREVAIL THRU AT LEAST 09/14Z...THEN VFR CIGS FL050 AGL GENERALLY
PREVAILING THE REMAINDER OF THE FCST PD.
DEE
PREV DISCUSSION... /ISSUED 258 PM CDT WED MAY 8 2013/
DISCUSSION...
PRECIPITATION CHANCES TONIGHT INTO THURSDAY MAIN FORECAST FOCUS IN
THE SHORTER TERM. EXTENDED FORECAST WILL DEAL WITH A RELATIVELY
BRIEF BUT SUBSTANTIAL COOLDOWN THIS WEEKEND...FOLLOWED BY A MUCH
WARMER PATTERN NEXT WEEK.
AFTERNOON SATELLITE IMAGERY SHOWED A COMPACT UPPER CIRC CENTER
PIVOTING TOWARD NERN NEBR WITH ANOTHER UPPER WAVE MOVG INTO ERN
KS. REMNANT SHOWER ACTIVITY ON A LOBE MOVING AROUND SD UPPER LOW
WAS MOVG TOWARD FAR ERN ZONES AS OF 19Z...WITH SCATTERED
CONVECTION DEVELOPING NEAR THERMAL BOUNDARY BETWEEN PRECIP COOLED
AIR AND LOCATIONS WHICH HAD CLEARED UNDER UPPER THERMAL TROUGH IN
NERN NEBR. WOULD EXPECTED SCATTERED CONVECTION NERN ZONES INTO AT
LEAST EARLY THIS EVENING. ANOTHER AREA WHERE ACTIVITY COULD BE
MORE WIDESPREAD...ESPECIALLY EARLY THIS EVENING...WOULD APPEAR TO
BE NEAR WARM FRONT WHICH HAD LIFTED INTO FAR SRN NEBR. IN FACT
EVEN IF CURRENT ACTIVITY DVLPG NEAR SRN NEBR BOUNDARY DECREASES
EARLY THIS EVENING...WE COULD SEE ADDITIONAL DEVELOPMENT LATE THIS
EVENING AS SUGGESTED BY THE HRRR AND 4KM WRF AS LOW LEVEL JET
STRENGTHENS SOUTH OF BOUNDARY. THE LATTER MODEL EVEN SUGGESTED
NERN NEBR ACTIVITY WOULD BEGIN TURNING SE LATER THIS EVENING
MEETING UP WITH ANY CONVECTION THAT WOULD INCREASE IN SERN NEBR
LATE THIS EVENING. GENERALLY INCREASED POPS MOST AREAS EARLY
TONIGHT AND LATEST TRENDS WILL CONTINUE TO BE MONITORED FOR LAST
MINUTE CHANGES TO 00Z-03Z PD. AS UPPER LOW OVR SD BEGINS OPENING
UP/DROPPING SE LATE TONIGHT...SOME LIGHT SHOWERS COULD MOVE BACK
INTO NERN NEBR TOWARD THU MORNING WITH A CONTINUED SOUTHWARD PUSH
OF THESE GENERALLY LIGHT SHOWERS THURSDAY MORNING. IN
ADDITION...HEATING AND UPPER LOW REMNANTS ON THURSDAY COULD BRING
SCATTERED SHOWERS/TSTMS JUST ABOUT ANYWHERE THURSDAY AFTN AND SOME
POPS WERE ADDED ALL ZONES. GFS/NAM LINGERED QUITE A BIT OF LOW
LEVEL MOISTURE ACROSS MUCH OF THE FORECAST AREA ON THURSDAY WHICH
COULD LIMIT THIS HEATING AND COULD PROVIDE A PSBL NEGATIVE.
FOR NOW FORECAST WAS KEPT DRY THURSDAY NIGHT ALTHOUGH COULD SEE A
LINGERING LIGHT SHOWER/ISOLD TSTM EARLY. CLEARING THEN EXPECTED
FRIDAY WITH RELATIVELY LIGHT WINDS AND SEASONAL OR SLIGHTLY COOLER
TEMPERATURES. A STRONG COLD FRONT STILL ON TRACK TO RACE ACROSS
THE AREA FRIDAY NIGHT WITH GUSTY WINDS AND COOLER READINGS
ON SATURDAY. MAINTAINED SMALL POPS WITH FRONTS PASSAGE NRN ZONES
FRI NIGHT BUT CONFIDENCE NOT HIGH ENOUGH TO INCLUDE ANY CHCS
FARTHER SOUTH. GUSTY NRLY WINDS LIKELY SATURDAY AS SUB-ZERO H85
AIR MOVES INTO NRN ZONES EARLY IN THE DAY BEFORE MODERATING.
AIRMASS IS COOL/DRY ENOUGH SO THAT WITH DECREASING WINDS SAT NIGHT
SEE NO REASON LOWS WON/T GET AT LEAST AS COOL AS LATEST MEX MOST
AREAS. THIS COULD LEAD TO SCATTERED FROST SUNDAY MORNING IF DWPTS
DON/T DRY OUT TOO MUCH. NO FROST WAS MENTIONED AT THIS TIME...BUT
IT IS CERTAINLY POSSIBLE.
WARMING TREND STILL ON TRACK THEN INTO NEXT WEEK WITH TUESDAY
LOOKING EXCEPTIONALLY WARM AHEAD OF COOL FRONT THAT SHOULD KNOCK A
FEW DEGREES OFF OF HIGHS BY DAY 7. A DRY FORECAST WAS MAINTAINED
IN THE EXTENDED UNTIL ALONG AND POST FRONTAL TUE NIGHT/WEDNESDAY.
CHERMOK
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
99/99
AREA FORECAST DISCUSSION
NWS ELKO NV
306 PM PDT THU MAY 9 2013
.SYNOPSIS...LINGERING MOISTURE AND UNSTABLE CONDITIONS WILL RESULT IN
CONTINUED THUNDERSTORM DEVELOPMENT THIS AFTERNOON AND FRIDAY
AFTERNOON. HIGH PRESSURE WILL MOVE INTO THE REGION THIS WEEKEND
AND USHER IN DRIER CONDITIONS...MEAN WHILE TEMPERATURES SOAR INTO
THE EIGHTIES.
&&
.SHORT TERM...TONIGHT THROUGH SATURDAY. AS OF 18Z TODAY...THE
SYNOPTIC PATTERN FEATURED HIGH PRESSURE OVER WASHINGTON STATE WITH
A BROAD H5 TROF OVER THE GREAT BASIN AND DESERT SOUTHWEST. AN
ACTIVE PATTERN IS ON TAP AGAIN. CONVECTION WAS SLOW TO START
TODAY...HOWEVER A NUMBER OF INGREDIENTS CAME TOGETHER
BY 19Z...RESULTING IN ISOLATED TSRA...ALONG WITH A FEW ENHANCED OUTFLOWS.
PWS RANGED FROM .40 TO .55 OF AN INCH...LI`S ARE NEGATIVE AND THE
CAPES SOARED OVER 600 J/KG IN MULTIPLE ZONES. HOWEVER...THE NAM12
AND THE HRRR WERE PINGING INTO DIFFERENT LOCALES IN THE LKN CWA
FOR CONVECTION. THE BEST CONVECTION ULTIMATELY MATERIALIZED OVER
LANDER...EUREKA...AND NORTHERN NYE. ACCORDING TO THE STORM TOTAL
PRECIP ON KLRX...THE CELLS WERE CONSIDERABLY DRIER TODAY AND THE
QPF WAS SHUNTED SOUTHWARD. EXPECTING ANOTHER ROUND OF CONVECTION
FRIDAY AFTERNOON...ESPECIALLY OVER WHITE PINE AND NORTHERN NYE.
HIGH PRESSURE WILL BUILD OVER THE BATTLE BORN STATE ON
SATURDAY...EXPECTING A ROUND OF SUBSIDENCE. SENSIBLE WEATHER-WISE
EXPECTING DRY AND WARM CONDITIONS WITH VALLEY TEMPERATURES
CLIMBING INTO THE 80S.
.LONG TERM...SATURDAY NIGHT THROUGH NEXT THURSDAY. DRY AND VERY WARM
ON THE LATE WEEKEND...AND CONTINUED DRY AND A SLIGHT COOLING TREND
FOR THE REMAINDER OF THE WEEK.
A STRONG HIGH PRESSURE RIDGE WILL BUILD INTO THE WESTERN CONUS THIS
WEEK AND THE AXIS WILL BE OVER NEVADA FROM SOUTHWEST TO NORTHEAST ON
THE WEEKEND. TEMPERATURES WILL BE VERY WARM SUNDAY...NEAR
RECORD...WHICH ARE IN THE UPPER 80S TO LOW 90S IN MOST PLACES. SOME
PLACES IN LOWER VALLEYS OF NORTHERN NYE COUNTY MAY TWEAK THE LOWER
90S SUNDAY AND MONDAY.
THE UPPER RIDGE CREEPS EAST AS A TROUGH OF LOW PRESSURE MOVES ASHORE
IN THE PACIFIC NORTHWEST. THIS WILL PROVIDE SOME COOLER AIR STARTING
LATER MONDAY IN FAR NORTHWEST NEVADA...ADVANCING EAST AND SOUTH
THROUGH THE WEEK. EXPECTING TEMPS BY THURSDAY TO BE IN THE 70S IN
THE FAR NORTH TO THE LOW 80S IN EUREKA/LANDER/SOUTHERN ELKO/WHITE
PINE TO THE MID 80S IN NORTHERN NYE. STILL VERY PLEASANT SPRING
TEMPS.
&&
.AVIATION...ANOTHER ROUND OF -SHRA/-TSRA EXPECTED 00Z-06Z FRI.
COVERAGE WILL BE LESS THAN PREVIOUS DAY. MAIN ISSUE WILL BE GUSTY
WINDS. SOME LIGHT DAMAGE TO PROPERTY OCCURRED EARLY THURSDAY WITH
DOWNBURSTS. VFR WILL PREVAIL OUTSIDE OF ANY CONVECTION. NORTHEAST
WINDS 5-15 MPH WILL PREVAIL UNTIL ABOUT 06Z FRIDAY THEN DIMINISH.
FRIDAY WILL SEE MORE THUNDERSTORMS AND SHOWERS WITH EVEN LESS
COVERAGE THAN THURSDAY. NORTHERLY WINDS 5-15 MPH WITH GUSTY WINDS
NEAR -TSRA/SHRA.
&&
.LKN WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
97/98/98
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
140 PM EDT THU MAY 9 2013
.SYNOPSIS...
A SPRAWLING UPPER LEVEL LOW IN PENNSYLVANIA WILL DRIFT NORTHEAST
INTO NEW ENGLAND TODAY. A SLOW MOVING COLD FRONT WILL CROSS THE
REGION ON SATURDAY. THESE SYSTEMS WILL KEEP THE CHANCE FOR SHOWERS
AND THUNDERSTORMS ACROSS CENTRAL NEW YORK AND NORTHEAST
PENNSYLVANIA TODAY TO SATURDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
1130 AM UPDATE...JUST MINOR ADJUSTMENTS TO NEAR TERM GRIDS. WILL
KEEP THE MENTION OF POTNL FOR +RA THIS AFTN WITH ANY TSTA. PREV
BLO...
930 AM UPDATE...
UPR LOW CNTRD OVER NE PA MOVG NEWD TDA...WITH SVRL EMBEDDED VORT
LOBES ROTATING ARND IT. PROFILES FOR THIS AFTN SHOW GNRLY 200-400
J/KG WITH SLIGHTLY LOWER PWAT`S. RUC SUGGESTS THAT LOW LVL
CONVERGENCE ASSCD WITH EWD MOVG SFC TROF MAY COUPLE WITH AN AREA
OF ENHANCED UPR LVL DVRGNC ACRS CNTRL NY. ANY TSRA THAT DVLP
COULD DROP LCLY HEAVY RAINFALL. PREV BLO...
3 AM UPDATE...
QUIET EARLY MORNING WITH ONLY A FEW SHOWERS LEFT. SOME FOG FORMING
WITH SATURATED LOW LEVELS. UPPER LEVEL LOW IN SE PA WILL CONTINUE
NE INTO SRN NEW ENGLAND TODAY. WITH THE LOW WILL BE ANOTHER AREA
OF SHOWERS THAT WILL MOVE NNW INTO NE PA AND THE CATSKILLS THIS
MORNING THEN THE REST OF THE AREA THIS AFTN. WITH DAYTIME HEATING
THE SHOWERS WILL BECOME MORE WIDESPREAD. TSTORMS ARE POSSIBLE
MOSTLY THIS AFTN. THEY COULD HAVE HEAVY RAIN. WITH ANOTHER AREA OF
1INCH PLUS PWATS ISOLATED AREAS COULD GET AN INCH OR TWO OF RAIN.
THE HIGHEST RAIN AMOUNTS WILL AGAIN BE IN THE EAST. LITTLE
FLOODING PROBLEMS EXPECTED THOUGH WITH MOST LOCATIONS UNDER HALF
AN INCH.
LATE TONIGHT INTO EARLY FRIDAY MORNING A BREAK IN THE SHOWERS AS
THE UL LOW MOVES OFF. MORE FOG POSSIBLE WITH A WET GROUND. MORE
SHOWERS APPROACH FROM THE WEST BUT SHOULD STAY IN WRN PA AND WRN
NY UNTIL DAYLIGHT FRIDAY.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
3 AM UPDATE...
CONTINUED UNSETTLED...COOL AND WET. A SFC LOW AND WEAK UPPER LEVEL
TROF MOVES ENE FROM ILLINOIS TO NY FRIDAY TO SATURDAY. THE LOW
STRENGTHENS WITH TIME...WHILE AN UL JET COUPLET SET UP AS THE
SOUTHERN JET MOVES TOWARD THE MID ATLANTIC. AHEAD OF THE LOW AND
TRAILING COLD FRONT BETTER MOISTURE AND HIGH TEMPS IN THE L70S
MOVE IN. THIS WILL DESTABILIZE THE LOWER LEVELS AND THE SHORT
WAVES WILL ADD LIFT. WIND FIELDS INCREASE AND TURN WITH HEIGHT FOR
SOME SPEED AND DIRECTIONAL SHEAR. WINDS NOT STRONG BUT ENOUGH TO
KEEP SHOWERS AND THUNDERSTORMS GOING ONCE THEY FORM LATE MORNING
INTO THE AFTERNOON. LIFT IS MARGINAL WITH CAPE UNDER 500. WIND
WILL BE THE BIGGEST THREAT. SPC HAS PA IN A SLIGHT CHC OF SEVERE.
ANOTHER HALF INCH OF RAIN IS EXPECTED FRI AFTN AND EVE. WILL NEED
TO WATCH FOR ISOLATED FLASH FLOODING WITH THUNDERSTORMS.
FRIDAY NIGHT THE SFC LOW MOVES FROM LAKE ONTARIO TO QUEBEC BUT THE
TRAILING COLD FRONT DOES NOT MAKE MUCH PROGRESS UNTIL SATURDAY.
THE BEST CHC OF SHOWERS WILL BE SAT MIDDAY AND AFTN IN NE PA AND
THE CATSKILLS. POSSIBLY SOME THUNDERSTORMS WITH WEAK LIFT AND
INSTABILITY. SAT NGT THE SFC FRONT MOVES EAST AND DAYTIME HEATING
WILL WANE CAUSING THE DIURNAL SHOWERS TO DIE. POPS DROP FROM
LIKELY SAT TO LOW CHC SAT OVERNIGHT.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
4 PM WED UPDATE... A TRANSITIONAL PATN IS EXPECTED THIS PD...AS
GLOBAL MODEL/WPC CONSENSUS POINTS TO A FAIRLY AMPLIFIED ERN
CANADIAN/NERN CONUS TROUGH EARLY IN THE PD...FOLLOWED BY A
TEMPORARY FILLING OF THIS FEATURE...AND MORE ZONAL PROGRESSION BY
NEXT TUE-WED.
SENSIBLE WX-WISE...MUCH CHILLIER TEMPS ARE FORESEEN SUN-MON...WITH
SCTD WRAP-ARND -SHRA ANTICIPATED...WITHIN THE CYCLONIC FLOW
REGIME. IN FACT...SOME WET SNOW FLAKES ARE EVEN PSBL LATE SUN
NGT INTO EARLY MON...SPCLY OVER THE HIGHER TERRAIN. THE OTHER PSBL
HIGHLIGHT OF THIS PD IS PROBABLE FROST/FREEZE CONDS...BOTH SUN AND
MON NGTS...IF ANY CLEARING CAN DVLP.
TEMPS SHOULD MODERATE TUE-WED (BACK INTO THE 60S AND 70S)...AS THE
FLOW TURNS SWLY...AND HGTS BUILD OVER THE ERN CONUS. BY WED...AN
APPROACHING UPR-LVL WAVE AND SFC FRNT COULD TRIGGER SOME
SHWRS...AND THUS WE`VE ADDED CHC POPS AT THIS EARLY JUNCTURE.
&&
.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
18Z THU UPDATE... AN AREA OF SHRA WILL SLOWLY PIVOT ACRS PTNS OF
THE RGN THIS AFTN FROM W TO E...PROVIDING OCNL RESTRICTIONS
(MAINLY MVFR) AT KELM/KITH/KBGM/KAVP. KRME AND KSYR SHOULD STAY VFR.
EARLY THIS EVE...THE SHRA SHOULD DISSIPATE EARLY (BY
00-02Z)...LEAVING MAINLY VFR CONDS THE FIRST PART OF THE NGT.
HOWEVER...BY/AFTER 06Z...WE`RE ANTICIPATING FOG AND PATCHY ST CLDS
TO DVLP (MVFR TO IFR RESTRICTIONS)...AGN MAINLY TARGETING
KELM/KITH/KBGM/KAVP.
CONDS SHOULD IMPROVE BY EARLY FRI (12-14Z)...WITH VFR THEN
PREVALENT THE REMAINDER OF THE VALID TAF PD.
S TO SW SFC WINDS THIS AFTN (5-8 KT)...WILL BECOME LGT AND VRBL
OVERNIGHT...THEN INCREASE OUT OF THE S AND SW FRI (8-15 KT).
OUTLOOK...
FRI NGT INTO SAT...RESTRICTIONS LIKELY IN SHRA.
SUN THROUGH TUE...MAINLY VFR.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...TAC
NEAR TERM...TAC
SHORT TERM...TAC
LONG TERM...MLJ
AVIATION...MLJ
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
1130 AM EDT THU MAY 9 2013
.SYNOPSIS...
A SPRAWLING UPPER LEVEL LOW IN PENNSYLVANIA WILL DRIFT NORTHEAST
INTO NEW ENGLAND TODAY. A SLOW MOVING COLD FRONT WILL CROSS THE
REGION ON SATURDAY. THESE SYSTEMS WILL KEEP THE CHANCE FOR SHOWERS
AND THUNDERSTORMS ACROSS CENTRAL NEW YORK AND NORTHEAST
PENNSYLVANIA TODAY TO SATURDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
1130 AM UPDATE...JUST MINOR ADJUSTMENTS TO NEAR TERM GRIDS. WILL
KEEP THE MENTION OF POTNL FOR +RA THIS AFTN WITH ANY TSTA. PREV
BLO...
930 AM UPDATE...
UPR LOW CNTRD OVER NE PA MOVG NEWD TDA...WITH SVRL EMBEDDED VORT
LOBES ROTATING ARND IT. PROFILES FOR THIS AFTN SHOW GNRLY 200-400
J/KG WITH SLIGHTLY LOWER PWAT`S. RUC SUGGESTS THAT LOW LVL
CONVERGENCE ASSCD WITH EWD MOVG SFC TROF MAY COUPLE WITH AN AREA
OF ENHANCED UPR LVL DVRGNC ACRS CNTRL NY. ANY TSRA THAT DVLP
COULD DROP LCLY HEAVY RAINFALL. PREV BLO...
3 AM UPDATE...
QUIET EARLY MORNING WITH ONLY A FEW SHOWERS LEFT. SOME FOG FORMING
WITH SATURATED LOW LEVELS. UPPER LEVEL LOW IN SE PA WILL CONTINUE
NE INTO SRN NEW ENGLAND TODAY. WITH THE LOW WILL BE ANOTHER AREA
OF SHOWERS THAT WILL MOVE NNW INTO NE PA AND THE CATSKILLS THIS
MORNING THEN THE REST OF THE AREA THIS AFTN. WITH DAYTIME HEATING
THE SHOWERS WILL BECOME MORE WIDESPREAD. TSTORMS ARE POSSIBLE
MOSTLY THIS AFTN. THEY COULD HAVE HEAVY RAIN. WITH ANOTHER AREA OF
1INCH PLUS PWATS ISOLATED AREAS COULD GET AN INCH OR TWO OF RAIN.
THE HIGHEST RAIN AMOUNTS WILL AGAIN BE IN THE EAST. LITTLE
FLOODING PROBLEMS EXPECTED THOUGH WITH MOST LOCATIONS UNDER HALF
AN INCH.
LATE TONIGHT INTO EARLY FRIDAY MORNING A BREAK IN THE SHOWERS AS
THE UL LOW MOVES OFF. MORE FOG POSSIBLE WITH A WET GROUND. MORE
SHOWERS APPROACH FROM THE WEST BUT SHOULD STAY IN WRN PA AND WRN
NY UNTIL DAYLIGHT FRIDAY.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
3 AM UPDATE...
CONTINUED UNSETTLED...COOL AND WET. A SFC LOW AND WEAK UPPER LEVEL
TROF MOVES ENE FROM ILLINOIS TO NY FRIDAY TO SATURDAY. THE LOW
STRENGTHENS WITH TIME...WHILE AN UL JET COUPLET SET UP AS THE
SOUTHERN JET MOVES TOWARD THE MID ATLANTIC. AHEAD OF THE LOW AND
TRAILING COLD FRONT BETTER MOISTURE AND HIGH TEMPS IN THE L70S
MOVE IN. THIS WILL DESTABILIZE THE LOWER LEVELS AND THE SHORT
WAVES WILL ADD LIFT. WIND FIELDS INCREASE AND TURN WITH HEIGHT FOR
SOME SPEED AND DIRECTIONAL SHEAR. WINDS NOT STRONG BUT ENOUGH TO
KEEP SHOWERS AND THUNDERSTORMS GOING ONCE THEY FORM LATE MORNING
INTO THE AFTERNOON. LIFT IS MARGINAL WITH CAPE UNDER 500. WIND
WILL BE THE BIGGEST THREAT. SPC HAS PA IN A SLIGHT CHC OF SEVERE.
ANOTHER HALF INCH OF RAIN IS EXPECTED FRI AFTN AND EVE. WILL NEED
TO WATCH FOR ISOLATED FLASH FLOODING WITH THUNDERSTORMS.
FRIDAY NIGHT THE SFC LOW MOVES FROM LAKE ONTARIO TO QUEBEC BUT THE
TRAILING COLD FRONT DOES NOT MAKE MUCH PROGRESS UNTIL SATURDAY.
THE BEST CHC OF SHOWERS WILL BE SAT MIDDAY AND AFTN IN NE PA AND
THE CATSKILLS. POSSIBLY SOME THUNDERSTORMS WITH WEAK LIFT AND
INSTABILITY. SAT NGT THE SFC FRONT MOVES EAST AND DAYTIME HEATING
WILL WANE CAUSING THE DIURNAL SHOWERS TO DIE. POPS DROP FROM
LIKELY SAT TO LOW CHC SAT OVERNIGHT.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
4 PM WED UPDATE... A TRANSITIONAL PATN IS EXPECTED THIS PD...AS
GLOBAL MODEL/WPC CONSENSUS POINTS TO A FAIRLY AMPLIFIED ERN
CANADIAN/NERN CONUS TROUGH EARLY IN THE PD...FOLLOWED BY A
TEMPORARY FILLING OF THIS FEATURE...AND MORE ZONAL PROGRESSION BY
NEXT TUE-WED.
SENSIBLE WX-WISE...MUCH CHILLIER TEMPS ARE FORESEEN SUN-MON...WITH
SCTD WRAP-ARND -SHRA ANTICIPATED...WITHIN THE CYCLONIC FLOW
REGIME. IN FACT...SOME WET SNOW FLAKES ARE EVEN PSBL LATE SUN
NGT INTO EARLY MON...SPCLY OVER THE HIGHER TERRAIN. THE OTHER PSBL
HIGHLIGHT OF THIS PD IS PROBABLE FROST/FREEZE CONDS...BOTH SUN AND
MON NGTS...IF ANY CLEARING CAN DVLP.
TEMPS SHOULD MODERATE TUE-WED (BACK INTO THE 60S AND 70S)...AS THE
FLOW TURNS SWLY...AND HGTS BUILD OVER THE ERN CONUS. BY WED...AN
APPROACHING UPR-LVL WAVE AND SFC FRNT COULD TRIGGER SOME
SHWRS...AND THUS WE`VE ADDED CHC POPS AT THIS EARLY JUNCTURE.
&&
.AVIATION /16Z THURSDAY THROUGH MONDAY/...
VARIABLE CONDITIONS EXISTS ACROSS THE TERMINALS THIS MORNING
RANGING FROM IFR TO VFR, DUE TO BOTH VSBYS/CIGS. BY MID MORNING
CONDITIONS WILL IMPROVE TO GENERALLY VFR WITH SHOWERS BECOMING MORE
NUMEROUS AS THE MORNING PROGRESSES UNDER THE UPPER LEVEL LOW. LATE
THIS AFTERNOON THE ACTIVITY WILL GRADUALLY DIMINISH AS THE UPPER
LEVEL FEATURE MOVES EAST OF THE AREA AND WITH THE LOSS OF DIURNAL
HEATING. OVERNIGHT THERE IS THE POTENTIAL FOR LOW CIGS AND VSBYS
TO DEVELOP AFTER 06Z ESPECIALLY IN THE SOUTHERN TIER.
WINDS GENERALLY 5 KNOTS OR LESS EARLY THIS MORNING EITHER E/SE OR
VARIABLE. S/SW WINDS LATER THIS MORNING 5-7 KNOTS BECOMING W/SW
THIS AFTERNOON THEN LIGHT THIS EVENING.
OUTLOOK...
FRI/SAT...MVFR PSBL...IN SCATTERED SHOWERS.
SUN/MON...MAINLY VFR.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...TAC
NEAR TERM...TAC
SHORT TERM...TAC
LONG TERM...MLJ
AVIATION...RRM
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
931 AM EDT THU MAY 9 2013
.SYNOPSIS...
A SPRAWLING UPPER LEVEL LOW IN PENNSYLVANIA WILL DRIFT NORTHEAST
INTO NEW ENGLAND TODAY. A SLOW MOVING COLD FRONT WILL CROSS THE
REGION ON SATURDAY. THESE SYSTEMS WILL KEEP THE CHANCE FOR SHOWERS
AND THUNDERSTORMS ACROSS CENTRAL NEW YORK AND NORTHEAST
PENNSYLVANIA TODAY TO SATURDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
930 AM UPDATE...
UPR LOW CNTRD OVER NE PA MOVG NEWD TDA...WITH SVRL EMBEDDED VORT
LOBES ROTATING ARND IT. PROFILES FOR THIS AFTN SHOW GNRLY 200-400
J/KG WITH SLIGHTLY LOWER PWAT`S. RUC SUGGESTS THAT LOW LVL
CONVERGENCE ASSCD WITH EWD MOVG SFC TROF MAY COUPLE WITH AN AREA
OF ENHANCED UPR LVL DVRGNC ACRS CNTRL NY. ANY TSRA THAT DVLP
COULD DROP LCLY HEAVY RAINFALL. PREV BLO...
3 AM UPDATE...
QUIET EARLY MORNING WITH ONLY A FEW SHOWERS LEFT. SOME FOG FORMING
WITH SATURATED LOW LEVELS. UPPER LEVEL LOW IN SE PA WILL CONTINUE
NE INTO SRN NEW ENGLAND TODAY. WITH THE LOW WILL BE ANOTHER AREA
OF SHOWERS THAT WILL MOVE NNW INTO NE PA AND THE CATSKILLS THIS
MORNING THEN THE REST OF THE AREA THIS AFTN. WITH DAYTIME HEATING
THE SHOWERS WILL BECOME MORE WIDESPREAD. TSTORMS ARE POSSIBLE
MOSTLY THIS AFTN. THEY COULD HAVE HEAVY RAIN. WITH ANOTHER AREA OF
1INCH PLUS PWATS ISOLATED AREAS COULD GET AN INCH OR TWO OF RAIN.
THE HIGHEST RAIN AMOUNTS WILL AGAIN BE IN THE EAST. LITTLE
FLOODING PROBLEMS EXPECTED THOUGH WITH MOST LOCATIONS UNDER HALF
AN INCH.
LATE TONIGHT INTO EARLY FRIDAY MORNING A BREAK IN THE SHOWERS AS
THE UL LOW MOVES OFF. MORE FOG POSSIBLE WITH A WET GROUND. MORE
SHOWERS APPROACH FROM THE WEST BUT SHOULD STAY IN WRN PA AND WRN
NY UNTIL DAYLIGHT FRIDAY.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
3 AM UPDATE...
CONTINUED UNSETTLED...COOL AND WET. A SFC LOW AND WEAK UPPER LEVEL
TROF MOVES ENE FROM ILLINOIS TO NY FRIDAY TO SATURDAY. THE LOW
STRENGTHENS WITH TIME...WHILE AN UL JET COUPLET SET UP AS THE
SOUTHERN JET MOVES TOWARD THE MID ATLANTIC. AHEAD OF THE LOW AND
TRAILING COLD FRONT BETTER MOISTURE AND HIGH TEMPS IN THE L70S
MOVE IN. THIS WILL DESTABILIZE THE LOWER LEVELS AND THE SHORT
WAVES WILL ADD LIFT. WIND FIELDS INCREASE AND TURN WITH HEIGHT FOR
SOME SPEED AND DIRECTIONAL SHEAR. WINDS NOT STRONG BUT ENOUGH TO
KEEP SHOWERS AND THUNDERSTORMS GOING ONCE THEY FORM LATE MORNING
INTO THE AFTERNOON. LIFT IS MARGINAL WITH CAPE UNDER 500. WIND
WILL BE THE BIGGEST THREAT. SPC HAS PA IN A SLIGHT CHC OF SEVERE.
ANOTHER HALF INCH OF RAIN IS EXPECTED FRI AFTN AND EVE. WILL NEED
TO WATCH FOR ISOLATED FLASH FLOODING WITH THUNDERSTORMS.
FRIDAY NIGHT THE SFC LOW MOVES FROM LAKE ONTARIO TO QUEBEC BUT THE
TRAILING COLD FRONT DOES NOT MAKE MUCH PROGRESS UNTIL SATURDAY.
THE BEST CHC OF SHOWERS WILL BE SAT MIDDAY AND AFTN IN NE PA AND
THE CATSKILLS. POSSIBLY SOME THUNDERSTORMS WITH WEAK LIFT AND
INSTABILITY. SAT NGT THE SFC FRONT MOVES EAST AND DAYTIME HEATING
WILL WANE CAUSING THE DIURNAL SHOWERS TO DIE. POPS DROP FROM
LIKELY SAT TO LOW CHC SAT OVERNIGHT.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
4 PM WED UPDATE... A TRANSITIONAL PATN IS EXPECTED THIS PD...AS
GLOBAL MODEL/WPC CONSENSUS POINTS TO A FAIRLY AMPLIFIED ERN
CANADIAN/NERN CONUS TROUGH EARLY IN THE PD...FOLLOWED BY A
TEMPORARY FILLING OF THIS FEATURE...AND MORE ZONAL PROGRESSION BY
NEXT TUE-WED.
SENSIBLE WX-WISE...MUCH CHILLIER TEMPS ARE FORESEEN SUN-MON...WITH
SCTD WRAP-ARND -SHRA ANTICIPATED...WITHIN THE CYCLONIC FLOW
REGIME. IN FACT...SOME WET SNOW FLAKES ARE EVEN PSBL LATE SUN
NGT INTO EARLY MON...SPCLY OVER THE HIGHER TERRAIN. THE OTHER PSBL
HIGHLIGHT OF THIS PD IS PROBABLE FROST/FREEZE CONDS...BOTH SUN AND
MON NGTS...IF ANY CLEARING CAN DVLP.
TEMPS SHOULD MODERATE TUE-WED (BACK INTO THE 60S AND 70S)...AS THE
FLOW TURNS SWLY...AND HGTS BUILD OVER THE ERN CONUS. BY WED...AN
APPROACHING UPR-LVL WAVE AND SFC FRNT COULD TRIGGER SOME
SHWRS...AND THUS WE`VE ADDED CHC POPS AT THIS EARLY JUNCTURE.
&&
.AVIATION /14Z THURSDAY THROUGH MONDAY/...
VARIABLE CONDITIONS EXISTS ACROSS THE TERMINALS THIS MORNING
RANGING FROM IFR TO VFR, DUE TO BOTH VSBYS/CIGS. BY MID MORNING
CONDITIONS WILL IMPROVE TO GENERALLY VFR WITH SHOWERS BECOMING MORE
NUMEROUS AS THE MORNING PROGRESSES UNDER THE UPPER LEVEL LOW. LATE
THIS AFTERNOON THE ACTIVITY WILL GRADUALLY DIMINISH AS THE UPPER
LEVEL FEATURE MOVES EAST OF THE AREA AND WITH THE LOSS OF DIURNAL
HEATING. OVERNIGHT THERE IS THE POTENTIAL FOR LOW CIGS AND VSBYS
TO DEVELOP AFTER 06Z ESPECIALLY IN THE SOUTHERN TIER.
WINDS GENERALLY 5 KNOTS OR LESS EARLY THIS MORNING EITHER E/SE OR
VARIABLE. S/SW WINDS LATER THIS MORNING 5-7 KNOTS BECOMING W/SW
THIS AFTERNOON THEN LIGHT THIS EVENING.
OUTLOOK...
FRI/SAT...MVFR PSBL...IN SCATTERED SHOWERS.
SUN/MON...MAINLY VFR.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...TAC
NEAR TERM...
SHORT TERM...TAC
LONG TERM...MLJ
AVIATION...RRM
AREA FORECAST DISCUSSION
NWS BISMARCK ND
924 PM CDT FRI MAY 10 2013
.UPDATE...
ISSUED AT 924 PM CDT FRI MAY 10 2013
LATEST RADAR TRENDS SHOW ISOLATED RAIN SHOWERS ASSOCIATED WITH THE
H85 COLD POOL MOVING SOUTHEAST FROM BRANDON TO WINNIPEG. HAVE
UPDATED THE FORECAST TO REFLECT ISOLATED SHOWERS IN NORTH CENTRAL
NORTH DAKOTA INCLUDING THE TURTLE MOUNTAINS THROUGH 06Z. HOWEVER CURRENT
TRENDS ON REFLECTIVITY SHOWS HIGHER VALUES HEADING JUST EAST OF
THE TURTLE MOUNTAINS. NONETHELESS...WILL CARRY ISOLATED POPS
THROUGH THE REST OF THIS EVENING. OTHERWISE REST OF FORECAST
REMAINS ON TRACK.
UPDATE ISSUED AT 632 PM CDT FRI MAY 10 2013
LATEST SATELLITE IMAGERY AND SURFACE OBSERVATIONS SHOW A SURFACE
COLD FRONT JUST EXITING DICKEY COUNTY WITH PRESSURE RISES
ENCOMPASSING THE REST OF WESTERN AND CENTRAL NORTH DAKOTA. MAXIMUM
3HR PRESSURE RISE BUBBLE OF 3MB NOW CENTERED OVER THE TURTLE
MOUNTAINS. THIS WILL SHIFT INTO THE JAMES RIVER VALLEY THIS EVENING
BEFORE EXITING FURTHER EAST AFTER 03Z. AS A RESULT...THE GUSTY WINDS
WILL GRADUALLY SUBSIDE AFTER 00Z AND WILL LET THE WIND ADVISORY AND
RED FLAG WARNING EXPIRE AT 7PM CST. LATEST REGIONAL RADAR SHOWS
PRECIPITATION IS NOW SOUTH AND EAST OF THE FORECAST AREA...AND WILL
CONTINUE WITH THE DRY WEATHER. FURTHER UPSTREAM...AN AREA OF SCT/BKN
CUMULUS ASSOCIATED WITH RAP H85 TEMPS OF 0C TO -2C IN SOUTHERN
CANADA WILL MOVE SOUTHEAST THROUGH 06Z. THIS WILL GRAZE NORTH
CENTRAL AND THE JAMES RIVER VALLEY THROUGH 06Z SATURDAY. EXPECT
CLEAR SKIES ACROSS ALL OF WESTERN AND CENTRAL NORTH DAKOTA
NEAR/AROUND 06Z SATURDAY. CLEAR/DRY WEATHER WILL CONTINUE THROUGH
SATURDAY.
ONLY ADJUSTMENT WAS TO LOWER MIN TEMPS A COUPLE OF DEGREES BASED
UPON UPSTREAM DEW POINTS AND LATEST GUIDANCE. REST OF FORECAST
ELEMENTS ARE TRENDING JUST FINE.
&&
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 353 PM CDT FRI MAY 10 2013
THE MAIN FOCUS FOR THE SHORT TERM FORECAST IS THE GUSTY
WINDS...PRECIPITATION CHANCE LATE AFTERNOON AND EARLY EVENING...AND
COLD OVERNIGHT LOW TEMPERATURES.
A COLD FRONT HAS PUSHED THROUGH ALL BUT THE SOUTHEAST PORTION OF
NORTH NORTH DAKOTA AS WINDS HAVE SHIFTED OUT OF THE NORTHWEST IN ALL
BUT FAR SOUTHEAST DICKY COUNTY. STRONG WINDS OF 30 TO 40 MPH
CONTINUE TO SPREAD SOUTHEAST BEHIND THE COLD FRONT AND AHEAD OF
PRESSURE RISES NEAR 1 TO 2 MB PER HOUR. WINDS WILL DIE OUT FROM
NORTHWEST TO SOUTHEAST JUST AFTER SUNSET AS DAYTIME MIXING AND
DIURNAL PRESSURE GRADIENTS WEAKEN.
VERY MINIMAL PRECIPITATION CHANCES REMAIN LATE THIS AFTERNOON FOR
THE FAR SOUTH AS AN AREA MID LEVEL MOISTURE ANCHORED IN THE H7 LEVEL
CONTINUES TO STREAM SOUTHEAST OUT OF EASTERN MONTANA INTO
SOUTHWESTERN NORTH DAKOTA. THIS IS SEEN IN WATER VAPOR AND INFRARED
SATELLITE IMAGERY. SCATTERED SHOWERS ARE SHOWING UP ON RADAR ACROSS
EASTERN MONTANA AND SOUTHWESTERN NORTH DAKOTA. HOWEVER...WITH A
DEWPOINT DEPRESSION NEAR 30 DEGREES AND VERY DRY AIR IN THE BOUNDARY
LAYER THIS ELEVATED PRECIPITATION DOES NOT APPEAR TO BE MAKING IT TO
THE GROUND.
STRONG SURFACE HIGH PRESSURE WILL MOVE IN OVERNIGHT AND CENTER OVER
NORTHWESTERN NORTH DAKOTA. VERY DRY AIR WITH DEWPOINTS IN THE TEENS
AND 20S COMBINED WITH LIGHT WINDS WILL MAXIMIZE RADIATIONAL COOLING.
12 UTC GFS AND NAM SUGGEST TEMPERATURES WILL DROP TO THE UPPER 20S
TO LOW 30S ACROSS ALL OF WESTERN AND CENTRAL NORTH DAKOTA.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 353 PM CDT FRI MAY 10 2013
THE EXTENDED PERIOD BEGINS SATURDAY NIGHT WITH WEAK RETURN FLOW WEST
DEVELOPING OVER THE CENTRAL AS SURFACE HIGH PRESSURE BUILDS EAST INTO
THE EASTERN DAKOTAS. EXPECT WARMER LOWS SUNDAY MORNING...MID
30S...ACROSS WESTERN NORTH DAKOTA AHEAD OF A WARM FRONT DRAPED
ACROSS EASTERN MONTANA. STILL COLD EAST NEAR THE SFC RIDGE AXIS WITH
LOWS FALLING INTO THE UPPER 20S.
UPPER LEVEL RIDGE AXIS BUILDS ACROSS THE ROCKIES INTO SASKATCHEWAN
SUNDAY DAYTIME...WITH RETURN FLOW/WAA INCREASING/DEVELOPING WEST TO
EAST THROUGH THE DAY. DRY WEATHER CONDITIONS WILL PERSIST...AND
SHOULD ALSO SEE A VERY NICE TEMPERATURE RECOVERY WEST WITH FORECAST
HIGHS SUNDAY CLIMBING TO NEAR 80 AS THE WARM FRONT SLOWLY NEARS THE
ND/MT BORDER AREA. COOLER ACROSS MY EASTERN COUNTIES IN THE LOWER
60S WHERE RETURN FLOW WILL BE WEAKER INITIALLY. MID 40S TO MID 50S
FOR LOWS SUNDAY NIGHT AS THE STRONG WARM FRONT MOVES EAST INTO THE
CENTRAL DAKOTAS. BOTH THE 12Z GFS AND 12Z ECMWF DEVELOP LIGHT QPF
ALONG TO AHEAD OF THE WARM FRONT SUNDAY NIGHT...SO OPTED TO
INTRODUCE SLIGHT CHANCES FOR RAIN MAINLY NORTH FOR NOW.
RIDGE CONTINUES TO BUILD EAST ON MONDAY IN RESPONSE TO A STRONG
UPPER LEVEL S/WV TROUGH APPROACHING THE PACIFIC NORTHWEST...WITH THE
RIDGE AXIS OVER THE DAKOTAS BY MONDAY AFTERNOON. ACCOMPANIED BY
ANOTHER SURGE OF WAA AND A DECENT WEST-NORTHWEST MIXING WIND OF 15
TO 25 MPH...EXPECT TO SEE WIDESPREAD HIGHS IN THE 80S...WITH AROUND
90 SOUTHWEST AND SOUTH CENTRAL UNDER THE STRONGER WAA. NEAR RECORD
HIGH TEMPERATURES ARE STILL VERY POSSIBLE SOUTH (RECORD HIGH AT
BISMARCK IS 91 AND THE RECORD HIGH AT DICKINSON IS 93).
THE REST OF THE WORK WEEK (TUESDAY THROUGH THURSDAY) WILL SEE A
QUASI-ZONAL MID/UPPER LEVEL FLOW REGIME ACROSS THE NORTHERN TIER OF
THE COUNTRY WITH THE UPPER LEVEL JET ALOFT. THIS IS EXPECTED TO
RESULT IN NEAR SEASONAL TEMPERATURES ALONG WITH ON AND OFF AGAIN
CHANCES FOR SHOWERS AND/OR THUNDERSTORMS. FOR THE END OF THE WORK
WEEK INTO THE FOLLOWING WEEKEND...LONG RANGE MODELS ARE INDICATING
BETTER CHANCES FOR WIDESPREAD PRECIPITATION AS A STRONGER S/WV
TROUGH APPROACHES THE PLAINS.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 632 PM CDT FRI MAY 10 2013
GUSTY NORTHWEST WINDS OF 20KT TO 30KT AT 00Z WILL DECREASE THIS
EVENING AND DIMINISH TO 10KT TO 15KT BY 03Z SATURDAY. SCT HIGH
BASED CUMULUS BETWEEN 7KFT-10KFT WILL GIVE WAY TO SKC AFTER 06Z.
VFR CIGS/VSBYS NEXT 24HR.
&&
.FIRE WEATHER...
ISSUED AT 632 PM CDT FRI MAY 10 2013
WILL LET THE RED FLAG WARNING EXPIRE AT 7 PM CST AS SCHEDULED WITH
WINDS DIMINISHING BELOW RED FLAG WARNING THRESHOLDS. MINIMUM
RELATIVE HUMIDITIES OCCURRING OVER THE LAST HOUR OR TWO...AND
EXPECT THEM TO SHOW A SLOW RISE THROUGH THE EVENING HOURS.
&&
.HYDROLOGY...
ISSUED AT 924 PM CDT FRI MAY 10 2013
THE LATEST RIVER READING AT WILLOW CREEK NEAR WILLOW CITY
AFFECTING MCHENRY AND BOTTINEAU COUNTIES HAS FALLEN BELOW MINOR
FLOOD STAGE AND IS FORECAST TO DECREASE OVER THE COMING DAYS. THUS
THE FLOOD WARNING HAS BEEN CANCELLED.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...KS
SHORT TERM...AJ
LONG TERM...NH
AVIATION...KS
FIRE WEATHER...KS
HYDROLOGY...KS/ACOOP
AREA FORECAST DISCUSSION
NWS BISMARCK ND
632 PM CDT FRI MAY 10 2013
.UPDATE...
ISSUED AT 632 PM CDT FRI MAY 10 2013
LATEST SATELLITE IMAGERY AND SURFACE OBSERVATIONS SHOW A SURFACE
COLD FRONT JUST EXITING DICKEY COUNTY WITH PRESSURE RISES
ENCOMPASSING THE REST OF WESTERN AND CENTRAL NORTH DAKOTA. MAXIMUM
3HR PRESSURE RISE BUBBLE OF 3MB NOW CENTERED OVER THE TURTLE
MOUNTAINS. THIS WILL SHIFT INTO THE JAMES RIVER VALLEY THIS EVENING
BEFORE EXITING FURTHER EAST AFTER 03Z. AS A RESULT...THE GUSTY WINDS
WILL GRADUALLY SUBSIDE AFTER 00Z AND WILL LET THE WIND ADVISORY AND
RED FLAG WARNING EXPIRE AT 7PM CST. LATEST REGIONAL RADAR SHOWS
PRECIPITATION IS NOW SOUTH AND EAST OF THE FORECAST AREA...AND WILL
CONTINUE WITH THE DRY WEATHER. FURTHER UPSTREAM...AN AREA OF SCT/BKN
CUMULUS ASSOCIATED WITH RAP H85 TEMPS OF 0C TO -2C IN SOUTHERN
CANADA WILL MOVE SOUTHEAST THROUGH 06Z. THIS WILL GRAZE NORTH
CENTRAL AND THE JAMES RIVER VALLEY THROUGH 06Z SATURDAY. EXPECT
CLEAR SKIES ACROSS ALL OF WESTERN AND CENTRAL NORTH DAKOTA
NEAR/AROUND 06Z SATURDAY. CLEAR/DRY WEATHER WILL CONTINUE THROUGH
SATURDAY.
ONLY ADJUSTMENT WAS TO LOWER MIN TEMPS A COUPLE OF DEGREES BASED
UPON UPSTREAM DEW POINTS AND LATEST GUIDANCE. REST OF FORECAST
ELEMENTS ARE TRENDING JUST FINE.
&&
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 353 PM CDT FRI MAY 10 2013
THE MAIN FOCUS FOR THE SHORT TERM FORECAST IS THE GUSTY
WINDS...PRECIPITATION CHANCE LATE AFTERNOON AND EARLY EVENING...AND
COLD OVERNIGHT LOW TEMPERATURES.
A COLD FRONT HAS PUSHED THROUGH ALL BUT THE SOUTHEAST PORTION OF
NORTH NORTH DAKOTA AS WINDS HAVE SHIFTED OUT OF THE NORTHWEST IN ALL
BUT FAR SOUTHEAST DICKY COUNTY. STRONG WINDS OF 30 TO 40 MPH
CONTINUE TO SPREAD SOUTHEAST BEHIND THE COLD FRONT AND AHEAD OF
PRESSURE RISES NEAR 1 TO 2 MB PER HOUR. WINDS WILL DIE OUT FROM
NORTHWEST TO SOUTHEAST JUST AFTER SUNSET AS DAYTIME MIXING AND
DIURNAL PRESSURE GRADIENTS WEAKEN.
VERY MINIMAL PRECIPITATION CHANCES REMAIN LATE THIS AFTERNOON FOR
THE FAR SOUTH AS AN AREA MID LEVEL MOISTURE ANCHORED IN THE H7 LEVEL
CONTINUES TO STREAM SOUTHEAST OUT OF EASTERN MONTANA INTO
SOUTHWESTERN NORTH DAKOTA. THIS IS SEEN IN WATER VAPOR AND INFRARED
SATELLITE IMAGERY. SCATTERED SHOWERS ARE SHOWING UP ON RADAR ACROSS
EASTERN MONTANA AND SOUTHWESTERN NORTH DAKOTA. HOWEVER...WITH A
DEWPOINT DEPRESSION NEAR 30 DEGREES AND VERY DRY AIR IN THE BOUNDARY
LAYER THIS ELEVATED PRECIPITATION DOES NOT APPEAR TO BE MAKING IT TO
THE GROUND.
STRONG SURFACE HIGH PRESSURE WILL MOVE IN OVERNIGHT AND CENTER OVER
NORTHWESTERN NORTH DAKOTA. VERY DRY AIR WITH DEWPOINTS IN THE TEENS
AND 20S COMBINED WITH LIGHT WINDS WILL MAXIMIZE RADIATIONAL COOLING.
12 UTC GFS AND NAM SUGGEST TEMPERATURES WILL DROP TO THE UPPER 20S
TO LOW 30S ACROSS ALL OF WESTERN AND CENTRAL NORTH DAKOTA.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 353 PM CDT FRI MAY 10 2013
THE EXTENDED PERIOD BEGINS SATURDAY NIGHT WITH WEAK RETURN FLOW WEST
DEVELOPING OVER THE CENTRAL AS SURFACE HIGH PRESSURE BUILDS EAST INTO
THE EASTERN DAKOTAS. EXPECT WARMER LOWS SUNDAY MORNING...MID
30S...ACROSS WESTERN NORTH DAKOTA AHEAD OF A WARM FRONT DRAPED
ACROSS EASTERN MONTANA. STILL COLD EAST NEAR THE SFC RIDGE AXIS WITH
LOWS FALLING INTO THE UPPER 20S.
UPPER LEVEL RIDGE AXIS BUILDS ACROSS THE ROCKIES INTO SASKATCHEWAN
SUNDAY DAYTIME...WITH RETURN FLOW/WAA INCREASING/DEVELOPING WEST TO
EAST THROUGH THE DAY. DRY WEATHER CONDITIONS WILL PERSIST...AND
SHOULD ALSO SEE A VERY NICE TEMPERATURE RECOVERY WEST WITH FORECAST
HIGHS SUNDAY CLIMBING TO NEAR 80 AS THE WARM FRONT SLOWLY NEARS THE
ND/MT BORDER AREA. COOLER ACROSS MY EASTERN COUNTIES IN THE LOWER
60S WHERE RETURN FLOW WILL BE WEAKER INITIALLY. MID 40S TO MID 50S
FOR LOWS SUNDAY NIGHT AS THE STRONG WARM FRONT MOVES EAST INTO THE
CENTRAL DAKOTAS. BOTH THE 12Z GFS AND 12Z ECMWF DEVELOP LIGHT QPF
ALONG TO AHEAD OF THE WARM FRONT SUNDAY NIGHT...SO OPTED TO
INTRODUCE SLIGHT CHANCES FOR RAIN MAINLY NORTH FOR NOW.
RIDGE CONTINUES TO BUILD EAST ON MONDAY IN RESPONSE TO A STRONG
UPPER LEVEL S/WV TROUGH APPROACHING THE PACIFIC NORTHWEST...WITH THE
RIDGE AXIS OVER THE DAKOTAS BY MONDAY AFTERNOON. ACCOMPANIED BY
ANOTHER SURGE OF WAA AND A DECENT WEST-NORTHWEST MIXING WIND OF 15
TO 25 MPH...EXPECT TO SEE WIDESPREAD HIGHS IN THE 80S...WITH AROUND
90 SOUTHWEST AND SOUTH CENTRAL UNDER THE STRONGER WAA. NEAR RECORD
HIGH TEMPERATURES ARE STILL VERY POSSIBLE SOUTH (RECORD HIGH AT
BISMARCK IS 91 AND THE RECORD HIGH AT DICKINSON IS 93).
THE REST OF THE WORK WEEK (TUESDAY THROUGH THURSDAY) WILL SEE A
QUASI-ZONAL MID/UPPER LEVEL FLOW REGIME ACROSS THE NORTHERN TIER OF
THE COUNTRY WITH THE UPPER LEVEL JET ALOFT. THIS IS EXPECTED TO
RESULT IN NEAR SEASONAL TEMPERATURES ALONG WITH ON AND OFF AGAIN
CHANCES FOR SHOWERS AND/OR THUNDERSTORMS. FOR THE END OF THE WORK
WEEK INTO THE FOLLOWING WEEKEND...LONG RANGE MODELS ARE INDICATING
BETTER CHANCES FOR WIDESPREAD PRECIPITATION AS A STRONGER S/WV
TROUGH APPROACHES THE PLAINS.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 632 PM CDT FRI MAY 10 2013
GUSTY NORTHWEST WINDS OF 20KT TO 30KT AT 00Z WILL DECREASE THIS
EVENING AND DIMINISH TO 10KT TO 15KT BY 03Z SATURDAY. SCT HIGH
BASED CUMULUS BETWEEN 7KFT-10KFT WILL GIVE WAY TO SKC AFTER 06Z.
VFR CIGS/VSBYS NEXT 24HR.
&&
.FIRE WEATHER...
ISSUED AT 632 PM CDT FRI MAY 10 2013
WILL LET THE RED FLAG WARNING EXPIRE AT 7 PM CST AS SCHEDULED WITH
WINDS DIMINISHING BELOW RED FLAG WARNING THRESHOLDS. MINIMUM
RELATIVE HUMIDITIES OCCURRING OVER THE LAST HOUR OR TWO...AND
EXPECT THEM TO SHOW A SLOW RISE THROUGH THE EVENING HOURS.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
RED FLAG WARNING UNTIL 7 PM CDT /6 PM MDT/ THIS EVENING FOR
NDZ001>003-009>011-017>019-021-031>033.
WIND ADVISORY UNTIL 7 PM CDT /6 PM MDT/ THIS EVENING FOR
NDZ001>005-009>013-017>023-031>035-040>046.
&&
$$
UPDATE...KS
SHORT TERM...AJ
LONG TERM...NH
AVIATION...KS
FIRE WEATHER...KS
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1229 AM CDT THU MAY 9 2013
.UPDATE...
ISSUED AT 1229 AM CDT THU MAY 9 2013
LATEST WATER VAPOR IMAGERY SHOWS A NORTHWESTERLY FLOW INTO NORTH
DAKOTA WITH AN UPSTREAM SHORTWAVE SEEN OVER SOUTHEAST ALBERTA. THE
00Z GFS SHOWS THIS H5-H3 SHORTWAVE WHICH TAKES IT JUST SOUTHEAST
OF GLASGOW BY 12Z THURSDAY. UPWARD VERTICAL MOTION PER H85-H3 OMEGA
LAYER AND UPPER LEVEL/H3 DIVERGENCE FIELD IS WEAK...WITH SCT TO BKN
MID/HIGH LEVEL CLOUDS PRESENT UPSTREAM AND THIS WILL TRANSLATE
WITH THE SHORTWAVE OVERNIGHT. WITH WEAK VERTICAL MOTION AND NO
SURFACE REFLECTION...WORST CASE SCENARIO IS SOME VIRGA POSSIBLE IN
THE BKN MID LEVEL DECK BUT NOT ENOUGH EVIDENCE OTHERWISE TO WARRANT
MEASURABLE POPS. THUS WILL CONTINUE WITH THE PREVIOUS FORECAST
WITH DRY CONDITIONS OVERNIGHT.
LATER THURSDAY...ANOTHER SHORTWAVE FOLLOWS BUT THE LATEST RAP/NAM/GFS
ALL INDICATE THAT THE PRECIPITATION FIELD REMAINS OUTSIDE OF OUR WESTERN
AND SOUTHWESTERN FORECAST PERIMETER. POPS WERE SCALED BACK EARLIER
FOR THURSDAY AND THIS TREND LOOKS GOOD. NO SIGNIFICANT CHANGES TO
CURRENT FORECAST.
UPDATE ISSUED AT 937 PM CDT WED MAY 8 2013
THE ONLY SIGNIFICANT CHANGE FOR THE FORECAST FOR TONIGHT INTO
TOMORROW WAS TO REMOVE POPS THROUGH 12 UTC...AND SCALE BACK TO
SLIGHT CHANCE NEAR THE MONTANA BORDER THROUGH THE DAY ON THURSDAY.
THE 00 UTC RAP/HRRR SIMULATED REFLECTIVITY DEPICT NO PRECIPITATION
THE REMAINDER OF THE NIGHT ACROSS EASTERN MONTANA AND WESTERN
NORTH DAKOTA...CONFIRMED BY ALL OTHER DETERMINISTIC MODELS OUTSIDE
OF THE 18 UTC GFS WHICH WAS DISCOUNTED. FOR TOMORROW...THE
SURFACE INSTABILITY AXIS LOOKS TO SETUP PRIMARILY ACROSS
SOUTHEAST MONTANA INTO NORTHEAST WYOMING...AND THUS SCALED BACK
POPS FOR THURSDAY TO JUST NEAR THE MONTANA BORDER. OTHERWISE...THE
FORECAST IS WELL ON TRACK FOR TONIGHT AND TOMORROW.
UPDATE ISSUED AT 648 PM CDT WED MAY 8 2013
NO SIGNIFICANT CHANGES REQUIRED WITH THIS FORECAST UPDATE OTHER
THAN TO BLEND TO THE 23 UTC OBSERVED TRENDS AND THE 22 UTC CONSENSUS
OF THE HIGH RESOLUTION NEAR TERM RAPIDLY UPDATING GUIDANCE. DID
MAINTAIN THE ISOLATED TO SCATTERED MENTION OF SHOWERS AND
THUNDERSTORM ACROSS THE FAR WEST LATE TONIGHT FOR NOW...AND WILL
RE-VISIT WITH THE 00 UTC RUNS. HOWEVER...WILL LIKELY DECREASE OR
REMOVE POPS WITH VERY WEAK FORCING AND MOISTURE ASSOCIATED WITH
THE IMPULSE PROPAGATING SOUTHEAST OUT OF CANADA THIS EVENING.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 358 PM CDT WED MAY 8 2013
THE MAIN FOCUS FOR THE REST OF THIS AFTERNOON AND EVENING WILL BE
THE POSSIBILITY OF SHOWERS AND THUNDERSTORMS ACROSS THE SOUTHEAST.
THE MAIN FOCUS FOR TONIGHT AND TOMORROW WILL BE THE POSSIBILITY OF
SHOWERS AND THUNDERSTORMS IN THE WEST.
A COLD FRONT WAS SLOWLY PUSHING SOUTH THIS AFTERNOON ACROSS FAR
SOUTHERN NORTH DAKOTA. THE COLD FRONT WILL BE THE PRIMARY LOCATION
OF ANY SHOWERS OR THUNDERSTORMS THAT DO DEVELOP. AHEAD OF THE
FRONT THE ATMOSPHERE CONTINUES TO DESTABILIZE AS EVIDENCED BY THE
CU FIELD IN VISIBLE SATELLITE. THE 17 UTC RAP PAINTS 400+ J/KG OF
CAPE ACROSS SOUTHERN NORTH DAKOTA. THE 15 UTC HRRR MODEL HAS
SCATTERED SHOWERS AND THUNDERSTORMS DEVELOPING ALONG AND AHEAD OF
THE FRONT LATER THIS AFTERNOON. ONE OF THE MAIN LIMITING FACTORS
ON WHETHER SHOWERS AND THUNDERSTORMS DEVELOP AND HOW WIDESPREAD
THEY BECOME IS THE BROAD SYNOPTIC SCALE SUBSIDENCE BEHIND THE
DEPARTING UPPER LEVEL LOW.
LATE TONIGHT AND TOMORROW MORNING A WEAK UPPER LEVEL SHORTWAVE TROUGH
WILL ENTER EASTERN MONTANA AND WESTERN NORTH DAKOTA. THIS SHORTWAVE
MAY PROVIDE ENOUGH ASCENT ALONG A DEVELOPING SURFACE BAROCLINIC
ZONE IN EASTERN MONTANA AND WESTERN NORTH DAKOTA TO SPARK SOME
ISOLATED RAIN SHOWERS. SURFACE HIGH PRESSURE AND COLD AIR
ADVECTION SHOULD KEEP CENTRAL AND EASTERN NORTH DAKOTA DRY.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 358 PM CDT WED MAY 8 2013
THE MAIN FOCUS OF THE EXTENDED PERIOD WILL BE THE COLD FRONT THAT IS
PROGGED TO DROP SOUTH OUT OF SOUTHERN CANADA AND INTO THE NORTHWEST
BY FRIDAY MORNING. THIS FRONT WILL CONTINUE TO MOVE SOUTH OVER THE
AREA...WITH IT MOVING INTO SOUTH DAKOTA BY EARLY SATURDAY MORNING.
THE CONCERN WILL LIE AHEAD OF THIS FRONT...WHERE THUNDERSTORMS MAY
BE POSSIBLE. ACCORDING TO THE 12Z NAM...SURFACE BASED CAPE AHEAD OF
THIS FRONT WILL BE IN THE 500 TO 600 J/KG RANGE...WITH THE 0-6 KM
BULK SHEAR BEING MORE THAN SUFFICIENT FOR AIDING IN THE DEVELOPMENT
OF SEVERE THUNDERSTORMS. ON THE OTHER HAND...THE GFS DEPICTS THE
STRONG 0-6 KM BULK SHEAR...BUT DOES NOT PAINT ANY SURFACE BASED CAPE
NOR MOST UNSTABLE CAPE OVER THE AREA. MOISTURE WILL ALSO BE A
LIMITING FACTOR AS FORECAST DEWPOINTS WILL ONLY BE IN THE 30S AND
40S. CURRENT THINKING IS THAT THERE WILL BE WIDESPREAD SHOWER
ACTIVITY AHEAD OF THE FRONT AND THAT IF ANY THUNDERSTORMS THAT DO
DEVELOP WILL REMAIN BELOW THE SEVERE THRESHOLD AND WILL BE OF THE
GARDEN VARIETY TYPE.
AHEAD OF THE AFOREMENTIONED COLD FRONT...TEMPERATURES WILL WARM
WITH THE RETURN FLOW AND BE IN THE 60S AND LOWER 70S. AS THE FRONT
MOVES THROUGH THE AREA...TEMPERATURES WILL RETURN TO BELOW
NORMAL...WITH TEMPERATURES IN THE UPPER 40S TO MID 50S. SATURDAY
NIGHT AND INTO SUNDAY MORNING...THERE IS THE POTENTIAL FOR
TEMPERATURES TO FLIRT WITH THE FREEZING MARK ACROSS MOST OF THE AREA
AND POSSIBLY ENDANGER NEW VEGETATION AND PLANT GROWTH.
THEREAFTER...TEMPERATURES WILL AGAIN WARM SUNDAY AS A WARM FRONT
MOVES EAST AND AN UPPER LEVEL RIDGE BUILDS EAST OVER THE NORTHERN
PLAINS. TEMPERATURES WILL CLIMB ABOVE NORMAL MONDAY WITH HIGHS IN
THE LOW TO MID 80S AS THE RIDGE AXIS MOVES OVERHEAD.
FOR THE REMAINDER OF THE PERIOD (TUESDAY ONWARDS)...QUASIZONAL FLOW
WILL DEVELOP AND TEMPERATURES WILL RETURN TO SEASONAL NORMS. THERE
IS A POSSIBILITY FOR SHOWERS AND THUNDERSTORMS DURING MONDAY
EVENING...HOWEVER THEY ARE NOT EXPECTED TO BECOME SEVERE. SHOWERS
WILL CONTINUE THROUGH EARLY THURSDAY MORNING.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1229 AM CDT THU MAY 9 2013
A COUPLE OF UPPER LEVEL DISTURBANCES WILL MOVE ACROSS WESTERN AND
CENTRAL NORTH DAKOTA THE REST OF WEDNESDAY NIGHT THROUGH THURSDAY.
LATEST SATELLITE IMAGERY SHOWS SCT/BKN MID LEVEL CLOUDS ASSOCIATED
WITH THESE DISTURBANCES ARE FILTERING IN FROM CANADA. HOWEVER...VFR
CIGS/VSBYS WILL CONTINUE WITH THE 06Z TAF ISSUANCE ALONG WITH A
DRY FORECAST.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...KS
SHORT TERM...AJ
LONG TERM...LTH
AVIATION...KS
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
417 AM EDT THU MAY 9 2013
.SYNOPSIS...
HIGH PRESSURE WILL ALLOW FOR DRY CONDITIONS ACROSS THE REGION THIS
MORNING. ANOTHER SYSTEM WILL BEGIN TO IMPACT THE AREA WITH
PRECIPITATION THIS AFTERNOON. A COLD FRONT WILL WORK THROUGH THE
REGION FRIDAY NIGHT INTO SATURDAY MORNING.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
PRECIPITATION HAS COME TO AN END ACROSS THE AREA THIS MORNING AND
CLOUD COVER HAS BEEN DECREASING OVER A LARGE PORTION OF THE AREA.
FOG HAS DEVELOPED ACROSS SOME LOCATIONS THIS MORNING. ALTHOUGH THE
FOG IS DENSE IN A FEW AREAS IT APPEARS TO BE PATCHY IN NATURE AT
THIS TIME. HIGHLIGHTED THE FOG IN THE HWO FOR THIS MORNING HOWEVER
DECIDED AGAINST ANY FOG HEADLINES DUE TO THE PATCHY NATURE OF THE
FOG. VISIBILITIES WILL IMPROVE ACROSS THE AREA THROUGH THE MORNING
DAYTIME HOURS.
SW WINDS WILL BRING WARMER AIR INTO THE FA TODAY WITH HIGH
TEMPERATURES EXPECTED TO BE IN THE UPPER 70S ACROSS THE FA. THE
NEXT SYSTEM WILL BEGIN TO WORK INTO MAINLY WESTERN PORTIONS OF THE
FA THIS AFTERNOON BRINGING SHOWERS AND THUNDERSTORMS TO THE AREA.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH MONDAY NIGHT/...
AN AREA OF LOW PRESSURE WILL BEGIN TO APPROACH THE AREA TONIGHT
AND WILL BE SITUATED NW OF THE FA BY FRIDAY MORNING. THIS FEATURE
WILL ALLOW FOR SHOWERS TO CONTINUE TO MOVE INTO THE AREA THROUGH
THE OVERNIGHT HOURS THURSDAY NIGHT. INSTABILITY IS LIMITED ACROSS
THE FA THURSDAY NIGHT AND THEREFORE LIMITED THUNDER MENTION TO A
SLIGHT CHANCE FOR MOST OF THE TONIGHT TIME FRAME.
BETTER INSTABILITY WILL BE IN PLACE ACROSS THE FA FOR FRIDAY AND
THEREFORE INCREASED THE THUNDER MENTION FOR THE DAYTIME HOURS ON
FRIDAY. MODELS ARE IN PRETTY GOOD AGREEMENT WITH THIS SYSTEM AND
THEREFORE INCREASED PRECIPITATION CHANCES ACROSS THE FA FOR
FRIDAY. SOME OF THE THUNDERSTORM ACTIVITY HAS THE POTENTIAL TO
BECOME SEVERE ACROSS THE AREA ON FRIDAY WITH THE MAIN THREATS
BEING DAMAGING WINDS AND LARGE HAIL. THE BEST CHANCE FOR SEVERE
THUNDERSTORMS WILL BE ACROSS THE SE HALF OF THE FA. CONTINUED TO
MENTION THE POTENTIAL FOR SEVERE WEATHER IN THE HWO FOR A MAJORITY
OF THE FA FOR FRIDAY.
A COLD FRONT WILL WORK INTO THE FA FRIDAY NIGHT AND INTO SATURDAY
MORNING. AFTER THIS FRONTAL PASSAGE THERE WILL BE SOME RESIDUAL
SHOWER ACTIVITY HOWEVER MOST OF THE THUNDERSTORM ACTIVITY WILL
DECREASE ACROSS THE FA THROUGH THE NIGHT FRIDAY NIGHT INTO
SATURDAY MORNING.
COOLER AND WELL BELOW NORMAL TEMPERATURES WILL WORK INTO THE AREA FOR THE
WEEKEND AFTER THE PASSAGE OF THE FRONTAL BOUNDARY. HIGH PRESSURE
WILL GRADUALLY WORK INTO THE REGION. SUNDAY NIGHT IS LOOKING TO BE A GOOD
RADIATIONAL COOLING NIGHT WITH LIGHT WINDS AND MOSTLY CLEAR SKIES.
THIS WILL ALLOW TEMPERATURES TO DROP DOWN INTO THE 30S ACROSS THE
FA SUNDAY NIGHT AND WILL LEND ITSELF TO THE POTENTIAL FOR FROST.
CONTINUED TO MENTION FROST IN THE FORECAST AND IN THE HWO. HIGH
PRESSURE WILL CONTINUE TO KEEP DRY CONDITIONS ACROSS THE FA FOR
MONDAY. WITH COOL NW FLOW ACROSS THE FA ON MONDAY BELOW NORMAL
TEMPERATURES WILL CONTINUE WITH HIGHS IN THE MIDDLE 50S TO LOW 60S.
&&
.LONG TERM /TUESDAY THROUGH WEDNESDAY/...
THE HIGH WILL SLOWLY PUSH OFF TO THE EAST THROUGH MID
WEEK...RESULTING IN DRY CONDITIONS AND WARMING TEMPERATURES EACH
DAY.
&&
.AVIATION /08Z THURSDAY THROUGH MONDAY/...
SATELLITE IMAGERY SHOWS A BROKEN DECK OF MID CLOUDS STILL MOVING
SOUTHEAST ACROSS THE REGION. RAP SEEMS TO HAVE A BETTER HANDLE ON
THIS AND SUGGESTS THAT THESE CLOUDS COULD LAST WELL THROUGH THE
NIGHT AT ALL BUT THE COLUMBUS TERMINALS. THIS SHOULD MINIMIZE
VISIBILITY ISSUES. HOWEVER KLUK HAS BEEN TRYING TO GO DOWN WHEN
THERE ARE BREAKS IN THE CLOUDS. AND IF THERE IS CLEARING THERE
LATE IN THE NIGHT THEN EXPECT LIFR TO PREVAIL.
HEADING INTO THE DAY IT APPEARS THAT THERE WILL ONLY BE SOME HIGH
AND MID CLOUDS UNTIL AFTERNOON WHEN CUMULUS DEVELOP. SCATTERED
SHOWERS AND STORMS MAY MOVE IN AFTER 18Z WITH ANY ACTIVITY
DIMINISHING AROUND 00Z. STILL EXPECT A FAIR AMOUNT OF MID AND HIGH
CLOUDS TO LINGER LATE IN THE TAF PERIOD.
OUTLOOK...MVFR CEILINGS AND VISIBILITIES POSSIBLE WITH THUNDERSTORMS
FRIDAY AFTERNOON AND EVENING. MVFR TO IFR CEILINGS AND MVFR
VISIBILITIES LIKELY LATE FRIDAY NIGHT INTO SATURDAY MORNING.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...NOVAK
NEAR TERM...NOVAK
SHORT TERM...NOVAK
LONG TERM...JGL
AVIATION...
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
134 AM EDT THU MAY 9 2013
.SYNOPSIS...
LOW PRESSURE WILL EXIT OUR REGION TONIGHT AS WEAK HIGH PRESSURE
BUILDS ACROSS OUR AREA. ANOTHER LOW PRESSURE SYSTEM WILL BRING A
CHANCE FOR PRECIPITATION LATE THURSDAY THROUGH FRIDAY. A STRONG
COLD FRONT WILL CROSS OUR AREA OVER THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
SCATTERED THUNDERSTORMS HAVE LINGERED INTO THE LATE EVENING AND
HAVE UPDATED FORECAST TO EXPAND AREA AND DURATION. STORM REPORTS
HAVE BEEN LIMITED TO SMALL HAIL. STILL EXPECT CONVECTION TO DIE
OFF WITHIN THE NEXT FEW HOURS...LEAVING PARTLY CLOUDY SKIES.
HIGHER MOISTURE CONTENT ACROSS THE SOUTH COULD RESULT IN FOG
DEVELOPMENT TONIGHT. THE MAIN LIMITING FACTOR FOR DENSE FOG
TONIGHT IS THE APPROACH OF HIGH CLOUDS FROM THE WEST LATE.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH FRIDAY NIGHT/...
THE UPPER LOW THAT HAS BEEN AFFECTING OUR WEATHER FOR THE PAST
SEVERAL DAYS WILL EXIT OUR REGION TONIGHT AS MID LEVEL RIDGING
BUILDS EASTWARD ACROSS OUR AREA. MAINLY FAIR WEATHER WITH WARM
TEMPERATURES ARE EXPECTED THROUGH THURSDAY AFTERNOON. CONVECTION
WILL BE SOMEWHAT LIMITED THURSDAY AFTERNOON DUE TO THE LACK OF ANY
APPRECIABLE FORCING. HOWEVER...THERE WILL BE SUFFICIENT DAYTIME
HEATING TO HELP TRIGGER SCATTERED SHOWERS WITH A POSSIBLE
THUNDERSTORM LATE AFTERNOON AND EARLY EVENING. LOW PRESSURE
CROSSING THE MIDWESTERN STATES WILL TRIGGER THUNDERSTORM
DEVELOPMENT TO OUR WEST IN AN INCREASINGLY UNSTABLE AIRMASS ON
THURSDAY. CONVECTION ALLOWING MODELS ARE IN FAIR AGREEMENT ON
BRINGING THE REMAINS OF THIS CONVECTION INTO OUR WESTERN ZONES
JUST AFTER SUNSET. SHEAR WILL BE INCREASING...ESPECIALLY IN THE
0-3 KM LEVELS THURSDAY EVENING. HOWEVER...INSTABILITY WILL BE ON
THE DECREASE. THEREFORE THE PROBABILITY FOR SEVERE WEATHER
OCCURRING THURSDAY EVENING AND THURSDAY NIGHT ACROSS OUR AREA
APPEARS LOW AT THIS TIME.
SHOWERS WITH A POSSIBLE RUMBLE OF THUNDER WILL OCCUR THURSDAY
NIGHT AS THE REMNANTS OF THURSDAYS CONVECTION TO OUR WEST PASSES
ACROSS PORTIONS OF OUR AREA. TEMPERATURES WILL BE MILD THURSDAY
NIGHT WITH WEAK SOUTHERLY FLOW. TEMPERATURES WILL STAY IN THE 60S
FOR THE MOST PART OVERNIGHT THURSDAY NIGHT.
A FRONTAL BOUNDARY WILL BE JUST NORTHWEST OF OUR AREA FRIDAY AS
THE AFOREMENTIONED LOW PASSES ACROSS THE SOUTHERN GREAT LAKES. OUR
AREA WILL LIE IN THE WARM SECTOR WITH INSTABILITY INCREASING THE
FIRST PARTS OF THE DAY FRIDAY...ESPECIALLY SOUTH OF THE INTERSTATE
71 CORRIDOR. MODELS ARE SHOWING INCREASING 0-3 KM SHEAR UP TO 40
KT ACROSS OUR SOUTHEAST CO-LOCATED WITH THE SECTOR OF INCREASED
INSTABILITY DURING THE EARLY AFTERNOON. CONVECTION WILL DEVELOPING
WITH PRE-FRONTAL FORCING ACROSS OUR AREA FRIDAY. INCREASED POPS TO
LIKELY AND CATEGORICAL FOR THE FRIDAY PERIOD. WHEN CONVECTION
DEVELOPS ACROSS THE SOUTHEASTERN PARTS OF OUR AREA...WITH THE ABOVE
MENTIONED SHEAR AND INSTABILITY...STORMS COULD BECOME ORGANIZED.
THE MAIN THREAT FROM THESE STORMS WILL BE DAMAGING WINDS AND LARGE
HAIL. WILL MENTION THIS THREAT IN THE HWO. ACROSS OUR
NORTHWEST...INSTABILITY AND SHEAR WILL BOTH BE WEAKER ON
FRIDAY...LIMITING THE THREAT FOR SEVERE WEATHER THERE.
PRECIPITATION WILL CONTINUE AHEAD OF THE FRONT INTO FRIDAY NIGHT.
INSTABILITY WILL DECREASE INTO THE EVENING...ENDING ANY SEVERE
THREAT ACROSS THE SOUTHEAST AND ENDING CHANCES FOR THUNDER
OVERNIGHT AS WELL. THE FRONT WILL PUSH SOUTHEAST OVERNIGHT FRIDAY
NIGHT WITH SHOWERS DECREASING TOWARD DAYBREAK SATURDAY.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
THE INITIAL COLD FRONT WILL BE PUSHING EAST OF THE AREA SATURDAY
MORNING WITH THE BULK OF THE PCPN ENDING ACROSS OUR EAST.
HOWEVER...A SECONDARY COLD FRONT WILL MOVE IN FROM THE NORTHWEST
SATURDAY AFTERNOON INTO SATURDAY EVENING. WEAK FORCING AND A NARROW
BAND OF DEEPER MOISTURE ALONG THE SECONDARY FRONT MAY BE ENOUGH TO
PRODUCE A FEW SHOWERS. EXPECT HIGHS GENERALLY IN THE MID 60S...BUT
POSSIBLY LEVELING OFF ACROSS AT LEAST THE NORTHWEST THROUGH THE
AFTERNOON AS BETTER CAA SETS UP.
AN UNSEASONABLY COOL AIRMASS WILL THEN SETTLE INTO THE AREA FOR
EARLY NEXT WEEK AS SURFACE HIGH PRESSURE BUILDS IN FROM THE WEST.
IT LOOKS LIKE THE HIGH WILL BE CENTERED JUST OFF TO OUR WEST AT 12Z
MON SO WE SHOULD END UP WITH GOOD RADIATIONAL COOLING SUNDAY NIGHT.
WILL CONTINUE TO TREND COOLER THAN GUIDANCE WITH LOWS GENERALLY IN
THE MID 30S AND INDICATE AREAS OF FROST. THE HIGH WILL SLOWLY PUSH
OFF TO THE EAST THROUGH MID WEEK...RESULTING IN DRY CONDITIONS AND
WARMING TEMPERATURES EACH DAY.
&&
.AVIATION /06Z THURSDAY THROUGH MONDAY/...
SATELLITE IMAGERY SHOWS A BROKEN DECK OF MID CLOUDS STILL MOVING
SOUTHEAST ACROSS THE REGION. RAP SEEMS TO HAVE A BETTER HANDLE ON
THIS AND SUGGESTS THAT THESE CLOUDS COULD LAST WELL THROUGH THE
NIGHT AT ALL BUT THE COLUMBUS TERMINALS. THIS SHOULD MINIMIZE
VISIBILITY ISSUES. HOWEVER KLUK HAS BEEN TRYING TO GO DOWN WHEN
THERE ARE BREAKS IN THE CLOUDS. AND IF THERE IS CLEARING THERE
LATE IN THE NIGHT THEN EXPECT LIFR TO PREVAIL.
HEADING INTO THE DAY IT APPEARS THAT THERE WILL ONLY BE SOME HIGH
AND MID CLOUDS UNTIL AFTERNOON WHEN CUMULUS DEVELOP. SCATTERED
SHOWERS AND STORMS MAY MOVE IN AFTER 18Z WITH ANY ACTIVITY
DIMINISHING AROUND 00Z. STILL EXPECT A FAIR AMOUNT OF MID AND HIGH
CLOUDS TO LINGER LATE IN THE TAF PERIOD.
OUTLOOK...MVFR CEILINGS AND VISIBILITIES POSSIBLE WITH THUNDERSTORMS
FRIDAY AFTERNOON AND EVENING. MVFR TO IFR CEILINGS AND MVFR
VISIBILITIES LIKELY LATE FRIDAY NIGHT INTO SATURDAY MORNING.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...LATTO
NEAR TERM...CONIGLIO/LATTO
SHORT TERM...LATTO
LONG TERM...JGL
AVIATION...
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
1155 AM EDT THU MAY 9 2013
.SYNOPSIS...
UPPER LEVEL LOW PRESSURE WILL DRIFT SLOWLY NORTHEAST INTO THE
CATSKILL REGION OF SOUTHEASTERN NEW YORK LATER TODAY. WEAK HIGH
PRESSURE WILL BUILD EAST OVER THE COMMONWEALTH THIS AFTERNOON INTO
EARLY FRIDAY. MILDER...AND MORE HUMID AIR WILL PUSH INTO THE
REGION FRIDAY AFTERNOON THROUGH SATURDAY...AHEAD OF A STRONG COLD
FRONT THAT WILL BRING UNSEASONABLY COOL AIR TO THE REGION LATER IN
THE WEEKEND INTO EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AN UPPER LOW...CENTERED OVER EASTERN PA EARLY TODAY WILL DRIFT
SLOWLY TO THE NE. HIGH RES SHORT RANGE MODELS HIGHLIGHT THE NW
QUAD OF THIS LOW FOR LOCALIZED ENHANCED PRECIP TODAY AS THE
SYSTEM LIFTS NORTHEAST AND MUCH OF THE REGION COMES UNDER THE AREA
OF STRONG FRONTOGENETIC FORCING IN THE BACK-SIDE DEFORMATION ZONE.
RAIN IS ALREADY FALLING IN A LOOSELY ORGANIZED BAND FROM THE LOWER
SUSQ VALLEY NNW UP INTO SWRN NY STATE. RUC SHOWS THE BEST FGEN
FORCING FOCUSING OVER THE AREA OF THE FLASH FLOOD WATCH INTO THE
AFTERNOON...WHILE ALSO GENERATING SOME MODEST AMOUNT OF
INSTABILITY UNDER THE CHILLY TEMPS ALOFT.
EXPECT THE RAIN TO CONTINUE THROUGH THE MID TO LATE MORNING HOURS
WITH AN AVERAGE OF 1-3 TENTHS OF RAINFALL.
FROM EARLIER...
DURING THE LATE MORNING AND AFTERNOON HOURS...WILL BE CLOSELY
MONITORING HIGH RES MODEL AND RADAR TRENDS FOR POTENTIAL
NARROW/QUASI STNRY BANDS OF HEAVY SHOWERS AND LOW-TOPPED TSRA
SETTING UP ON A NW-SE AXIS IN THE WELL ALIGNED NW FLOW JUST TO THE
WEST AND SW OF THE DEPARTING UPPER LOW. A NARROW RIBBON OF
RELATIVELY HIGHER PWAT AIR /JUST OVER AND INCH/ WILL BE SHIFTING
SLOWLY EAST FROM THE ALLEGHENIES...TO THE CENTRAL MTNS AND SUSQ
VALLEY BY EARLY THIS EVENING.
MIXED LAYER...MU CAPE VALUES THIS RAMP UP TO 500-900 J/KG DURING THE
MIDDAY AND AFTERNOON HOURS /WITH HIGHER CAPES OF 1000-1500 J/KG
LIKELY DEVELOPING ACROSS SWRN PENN AND INTO THE LAUREL HIGHLANDS.
THIS THIN CAPE WILL ALLOW PARCELS TO ASCEND TO 5-8 KFT ABOVE THE
-20C LEVEL LEADING TO SOME LOW-TOPPED TSRA WITH SMALL HAIL AS THE
WET BULB ZERO LEVEL WILL BE VERY LOW...AND ONLY AROUND 7 KFT AGL.
POPS TODAY WILL BE NEAR 100 PERCENT FOR MUCH OF CENTRAL AND NRN
PA...WITH SURROUNDING AREAS IN THE LIKELY CATEGORY FOR SHOWERS AND
SCATTERED TSRA GIVEN THE ABOVE FACTORS. ALTHOUGH BASIN AVERAGE
RAINFALL TODAY WILL BE JUST A TENTH TO ONE QUARTER OF AN INCH IN
MANY LOCATIONS...THERE WILL LIKELY BE A FEW NARROW BANDS OF HEAVY
RAINFALL EXCEEDING ONE INCH ONCE AGAIN TODAY.
PINNING DOWN THE EXACT LOCATION OF THESE MESOSCALE FEATURES IS
QUITE DIFFICULT...BUT HIGH RES MODEL LOW-MID LEVEL FRONTOGENESIS
AND MOISTURE CONVERGENCE INDICATES THE BEST CHANCE FOR HEAVIER
RAINFALL WILL BE ACROSS THE NCENT MTNS AND SUSQ VALLEY...IN CLOSE
PROXIMITY TO WHERE WE HAD LOCALLY OVER 2 INCHES WEDNESDAY. AS A
RESULT...A FLASH FLOOD WATCH WAS POSTED FOR TODAY /14Z-00Z FRIDAY
FOR 11 COUNTIES IN THE AFOREMENTIONED AREA OF HEAVY RAIN/.
DESPITE BREAKS OF SUNSHINE CLOUDS SHOULD PREDOMINATE TODAY. MDL 8H
TEMPS ARND 9C ARE SUPPORTIVE OF HIGHS FROM THE U60S ACROSS THE
ALLEGHENIES...TO THE L-M70S OVR THE SUSQ VALLEY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM FRIDAY/...
TONIGHT WILL SEE A STEADILY DECREASING TREND IN THE SHOWERS EARLY
ON...FOLLOWED BY SOME PARTIAL CLEARING AND LIGHT WIND LEADING TO THE
LIKELIHOOD OF FAIRLY WIDESPREAD FOG. MIN TEMPS WILL BE IN THE MID
40S TO LOWER 50S.
FRIDAY WILL SEE A RETURN OF MOISTURE AND WARMER TEMPS AS A DEEP
SWRLY FLOW DEVELOPS AHEAD OF A SLOW-MOVING/DYING COLD FRONT HEADING
EAST FORM THE OHIO VALLEY. 0-3KM HELICITY PEAKS BETWEEN 150 AND 250
M2/S2 FRIDAY AFTERNOON NEAR AND JUST TO THE SOUTH OF A WARM FRONT
AND SSWRLY 850 MB JET OF 30-35 KTS. POCKETS OF ML MU CAPE EXCEEDING
1500 J/KG WILL DEVELOPS IN WARMER AND MORE HUMID AIR MASS...AND
ACROSS THE FAR NW FRIDAY AFTERNOON /THEN OVER THE FAR SE TWD 00Z
SAT/...0-1KM EHI VALUES ARE EXPECTED TO RISE TO BETWEEN 1-1.5 MS/S2
SUPPORTING ROTATING UPDRAFTS IN SOME OF THE TSRA. SPC/S DAY 2
OUTLOOK TARGETS MUCH OF THE CWA FOR A SLIGHT RISK OF SVR.
THE BIG QUESTION/UNCERTAINTY...AS USUAL...SURROUNDING THE EXTENT OF
THE SVR THREAT FRIDAY AFTERNOON AND EVENING WILL BE THE AMOUNT OF
SUNSHINE/INSTABILITY THAT WILL FORM IN THE WARM SECTOR JUST AHEAD OF
THE INCREASING LARGE SCALE FORCING AND APPROACHING SFC
CFRONT.
HIGH TEMPS FRIDAY WILL RANGE FROM AROUND 70F ACROSS THE NW MTNS...TO
A BALMY 75-80 DEGREES FROM THE CENTRAL MTNS...SE TO THE LOWER SUSQ
VALLEY.
&&
.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
NOT A LOT OF CHANGE FOR FRIDAY NIGHT INTO SAT NIGHT. SERIES OF
COLD FRONTS MOVE ACROSS. ONE FRONT EARLY SAT...THEN ANOTHER
SATURDAY NIGHT. THE REAL COLD AIR WILL COME IN LATER
SUNDAY...BEHIND THE UPPER LVL FRONT. NEAR RECORD COLD LIKELY FROM
LATE SUNDAY INTO TUE AM. FROST AND FREEZE ISSUES WILL BE LIKELY.
AS THE HIGH MOVES TO TH SE LATE TUE...MODELS SHOW A STRONG
WESTERLY FLOW OF VERY WARM AIR FOR WED INTO THU... BEFORE ANOTHER
COLD SPELL LATER IN THE WEEK. PATTERN SUPPORT STRONG TO SEVERE
STORMS POSSIBLE WITH WARM FRONT...DID PUT LOW POPS IN ALONG THE NY
BORDER.
DID NOT GO TO CRAZY WITH MAX TEMPS AT THIS POINT...BUT COULD SEE
SOME MID 80S.
&&
.AVIATION /16Z THURSDAY THROUGH MONDAY/...
A STORM SYSTEM WILL CONTINUE TO LIFT SLOWLY INTO NEW ENGLAND
THROUGH FRIDAY. BANDS OF SHOWERS ROTATING ABOUT THIS LOW WILL
CONTINUE THROUGH THE AFTERNOON. THE SHOWERS WILL BE MAINLY LIGHT
THROUGH THE MORNING HOURS...BUT AS THE ATMOSPHERE BECOMES MORE
UNSTABLE...HEAVIER SHOWERS AND ISOLATED THUNDERSTORMS WILL BECOME
POSSIBLE.
EXPECT MVFR/IFR SLOWLY LIFTING WITH MOST SITES BEING VFR BY MID TO
LATE DAY...BUT WITH LOCAL REDUCTIONS LIKELY IN THE HEAVIER SHOWERS
AND THUNDERSTORMS.
AS THE LOW MOVES TO THE NORTHEAST THE SHOWERS AND THUNDERSTORMS
WILL TAPER OFF AND SKIES WILL BEGIN TO CLEAR TONIGHT AS WEAK HIGH
PRESSURE BUILDS OVER THE COMMONWEALTH BRINGING MOSTLY VFR FLYING
CONDITIONS. AREAS OF FOG WILL BECOME POSSIBLE...ESPECIALLY WHERE
RAIN FALLS THIS AFTERNOON AND EVENING.
.OUTLOOK...
FRI...SCT SHOWERS AND PERHAPS A THUNDERSTORM LATE ACCOMPANIED BY
LOCAL MVFR CONDITIONS.
SAT...MORE SHOWERS POSSIBLE WITH A COLD FRONT.
SUN...SHOWERS EARLY...THEN IMPROVING CONDITIONS.
MON...NO SIG WX.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH UNTIL 8 PM EDT THIS EVENING FOR PAZ006-012-
037-041-045-046-049>052-056-057-063.
&&
$$
SYNOPSIS...LA CORTE/LAMBERT
NEAR TERM...LA CORTE/LAMBERT
SHORT TERM...FITZGERALD/LAMBERT
LONG TERM...MARTIN
AVIATION...LA CORTE/CERU
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
1019 AM EDT THU MAY 9 2013
.SYNOPSIS...
UPPER LEVEL LOW PRESSURE CENTERED WILL DRIFT SLOWLY NORTHEAST
INTO THE CATSKILL REGION OF SOUTHEASTERN NEW YORK LATER TODAY.
WEAK HIGH PRESSURE WILL BUILD EAST OVER THE COMMONWEALTH THIS
AFTERNOON INTO EARLY FRIDAY. MILDER...AND MORE HUMID AIR WILL PUSH
INTO THE REGION FRIDAY AFTERNOON THROUGH SATURDAY...AHEAD OF A
STRONG COLD FRONT THAT WILL BRING UNSEASONABLY COOL AIR TO THE
REGION LATER IN THE WEEKEND INTO EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AN UPPER LOW...CENTERED OVER EASTERN PA EARLY TODAY WILL DRIFT
SLOWLY TO THE NE. HIGH RES SHORT RANGE MODELS HIGHLIGHT THE NW
QUAD OF THIS LOW FOR LOCALIZED ENHANCED PRECIP TODAY AS THE
SYSTEM LIFTS NORTHEAST AND MUCH OF THE REGION COMES UNDER THE AREA
OF STRONG FRONTOGENETIC FORCING IN THE BACK-SIDE DEFORMATION ZONE.
RAIN IS ALREADY FALLING IN A LOOSELY ORGANIZED BAND FROM THE LOWER
SUSQ VALLEY NNW UP INTO SWRN NY STATE. RUC SHOWS THE BEST FGEN
FORCING FOCUSING OVER THE AREA OF THE FLASH FLOOD WATCH INTO THE
AFTERNOON...WHILE ALSO GENERATING SOME MODEST AMOUNT OF
INSTABILITY UNDER THE CHILLY TEMPS ALOFT.
EXPECT THE RAIN TO CONTINUE THROUGH THE MID TO LATE MORNING HOURS
WITH AN AVERAGE OF 1-3 TENTHS OF RAINFALL.
FROM EARLIER...
DURING THE LATE MORNING AND AFTERNOON HOURS...WILL BE CLOSELY
MONITORING HIGH RES MODEL AND RADAR TRENDS FOR POTENTIAL
NARROW/QUASI STNRY BANDS OF HEAVY SHOWERS AND LOW-TOPPED TSRA
SETTING UP ON A NW-SE AXIS IN THE WELL ALIGNED NW FLOW JUST TO THE
WEST AND SW OF THE DEPARTING UPPER LOW. A NARROW RIBBON OF
RELATIVELY HIGHER PWAT AIR /JUST OVER AND INCH/ WILL BE SHIFTING
SLOWLY EAST FROM THE ALLEGHENIES...TO THE CENTRAL MTNS AND SUSQ
VALLEY BY EARLY THIS EVENING.
MIXED LAYER...MU CAPE VALUES THIS RAMP UP TO 500-900 J/KG DURING THE
MIDDAY AND AFTERNOON HOURS /WITH HIGHER CAPES OF 1000-1500 J/KG
LIKELY DEVELOPING ACROSS SWRN PENN AND INTO THE LAUREL HIGHLANDS.
THIS THIN CAPE WILL ALLOW PARCELS TO ASCEND TO 5-8 KFT ABOVE THE
-20C LEVEL LEADING TO SOME LOW-TOPPED TSRA WITH SMALL HAIL AS THE
WET BULB ZERO LEVEL WILL BE VERY LOW...AND ONLY AROUND 7 KFT AGL.
POPS TODAY WILL BE NEAR 100 PERCENT FOR MUCH OF CENTRAL AND NRN
PA...WITH SURROUNDING AREAS IN THE LIKELY CATEGORY FOR SHOWERS AND
SCATTERED TSRA GIVEN THE ABOVE FACTORS. ALTHOUGH BASIN AVERAGE
RAINFALL TODAY WILL BE JUST A TENTH TO ONE QUARTER OF AN INCH IN
MANY LOCATIONS...THERE WILL LIKELY BE A FEW NARROW BANDS OF HEAVY
RAINFALL EXCEEDING ONE INCH ONCE AGAIN TODAY.
PINNING DOWN THE EXACT LOCATION OF THESE MESOSCALE FEATURES IS
QUITE DIFFICULT...BUT HIGH RES MODEL LOW-MID LEVEL FRONTOGENESIS
AND MOISTURE CONVERGENCE INDICATES THE BEST CHANCE FOR HEAVIER
RAINFALL WILL BE ACROSS THE NCENT MTNS AND SUSQ VALLEY...IN CLOSE
PROXIMITY TO WHERE WE HAD LOCALLY OVER 2 INCHES WEDNESDAY. AS A
RESULT...A FLASH FLOOD WATCH WAS POSTED FOR TODAY /14Z-00Z FRIDAY
FOR 11 COUNTIES IN THE AFOREMENTIONED AREA OF HEAVY RAIN/.
DESPITE BREAKS OF SUNSHINE CLOUDS SHOULD PREDOMINATE TODAY. MDL 8H
TEMPS ARND 9C ARE SUPPORTIVE OF HIGHS FROM THE U60S ACROSS THE
ALLEGHENIES...TO THE L-M70S OVR THE SUSQ VALLEY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM FRIDAY/...
TONIGHT WILL SEE A STEADILY DECREASING TREND IN THE SHOWERS EARLY
ON...FOLLOWED BY SOME PARTIAL CLEARING AND LIGHT WIND LEADING TO THE
LIKELIHOOD OF FAIRLY WIDESPREAD FOG. MIN TEMPS WILL BE IN THE MID
40S TO LOWER 50S.
FRIDAY WILL SEE A RETURN OF MOISTURE AND WARMER TEMPS AS A DEEP
SWRLY FLOW DEVELOPS AHEAD OF A SLOW-MOVING/DYING COLD FRONT HEADING
EAST FORM THE OHIO VALLEY. 0-3KM HELICITY PEAKS BETWEEN 150 AND 250
M2/S2 FRIDAY AFTERNOON NEAR AND JUST TO THE SOUTH OF A WARM FRONT
AND SSWRLY 850 MB JET OF 30-35 KTS. POCKETS OF ML MU CAPE EXCEEDING
1500 J/KG WILL DEVELOPS IN WARMER AND MORE HUMID AIR MASS...AND
ACROSS THE FAR NW FRIDAY AFTERNOON /THEN OVER THE FAR SE TWD 00Z
SAT/...0-1KM EHI VALUES ARE EXPECTED TO RISE TO BETWEEN 1-1.5 MS/S2
SUPPORTING ROTATING UPDRAFTS IN SOME OF THE TSRA. SPC/S DAY 2
OUTLOOK TARGETS MUCH OF THE CWA FOR A SLIGHT RISK OF SVR.
THE BIG QUESTION/UNCERTAINTY...AS USUAL...SURROUNDING THE EXTENT OF
THE SVR THREAT FRIDAY AFTERNOON AND EVENING WILL BE THE AMOUNT OF
SUNSHINE/INSTABILITY THAT WILL FORM IN THE WARM SECTOR JUST AHEAD OF
THE INCREASING LARGE SCALE FORCING AND APPROACHING SFC
CFRONT.
HIGH TEMPS FRIDAY WILL RANGE FROM AROUND 70F ACROSS THE NW MTNS...TO
A BALMY 75-80 DEGREES FROM THE CENTRAL MTNS...SE TO THE LOWER SUSQ
VALLEY.
&&
.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
NOT A LOT OF CHANGE FOR FRIDAY NIGHT INTO SAT NIGHT. SERIES OF
COLD FRONTS MOVE ACROSS. ONE FRONT EARLY SAT...THEN ANOTHER
SATURDAY NIGHT. THE REAL COLD AIR WILL COME IN LATER
SUNDAY...BEHIND THE UPPER LVL FRONT. NEAR RECORD COLD LIKELY FROM
LATE SUNDAY INTO TUE AM. FROST AND FREEZE ISSUES WILL BE LIKELY.
AS THE HIGH MOVES TO TH SE LATE TUE...MODELS SHOW A STRONG
WESTERLY FLOW OF VERY WARM AIR FOR WED INTO THU... BEFORE ANOTHER
COLD SPELL LATER IN THE WEEK. PATTERN SUPPORT STRONG TO SEVERE
STORMS POSSIBLE WITH WARM FRONT...DID PUT LOW POPS IN ALONG THE NY
BORDER.
DID NOT GO TO CRAZY WITH MAX TEMPS AT THIS POINT...BUT COULD SEE
SOME MID 80S.
&&
.AVIATION /14Z THURSDAY THROUGH MONDAY/...
A LOW PRESSURE SYSTEM MOVING THROUGH PA IS FORECAST TO SLOWLY
LIFT NORTHEAST INTO NEW ENGLAND THROUGH FRIDAY. SCATTERED SHOWERS
MOVING AROUND THIS LOW WILL CONTINUE THROUGH THE MORNING AND
AFTERNOON. THE SHOWERS WILL BE MAINLY LIGHT THROUGH THE MORNING
HOURS...INTENSIFYING BY LATE MORNING AND AFTERNOON DUE TO
CONVECTION. DUE TO THE COPIOUS MOISTURE...EXPECT PATCHY
FOG/MIST...ESPECIALLY AT MDT AND LNS AND REGIONS WHERE MORE
WIDESPREAD PRECIPITATION FELL YESTERDAY...THROUGH 14Z. EXPECT
MVFR/IFR...WITH SOME SITES POTENTIALLY REACHING LIFR...VSBYS THIS
MORNING. ANY FOG/MIST WILL LIFT/DISSIPATE BY MID MORNING...WITH
SHOWERS CONTINUING AND THUNDERSTORMS POSSIBLE IN AFTERNOON. IFR
CIGS AND VSBYS ARE POSSIBLE IN AND AROUND THUNDERSTORM
ACTIVITY...WHERE THE HIGHEST PROBABILITIES WILL BE AT UNV AND IPT
TAF SITES.
AS THE LOW MOVES TO THE NORTHEAST THE SHOWERS AND THUNDERSTORMS
WILL TAPER OFF AND SKIES WILL BEGIN TO CLEAR TONIGHT AS WEAK HIGH
PRESSURE BUILDS OVER THE COMMONWEALTH BRINGING MOSTLY VFR FLYING
CONDITIONS.
.OUTLOOK...
FRI...COLD FRONT MOVES THROUGH. SCT SHOWERS AND PERHAPS A
THUNDERSTORM LATE ACCOMPANIED BY LOCAL MVFR CONDITIONS.
SAT...MORE SHOWERS POSSIBLE WITH ANOTHER COLD FRONT.
SUN...SHOWERS EARLY...THEN IMPROVING CONDITIONS.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH UNTIL 8 PM EDT THIS EVENING FOR PAZ006-012-
037-041-045-046-049>052-056-057-063.
&&
$$
SYNOPSIS...LA CORTE/LAMBERT
NEAR TERM...LA CORTE/LAMBERT
SHORT TERM...FITZGERALD/LAMBERT
LONG TERM...MARTIN
AVIATION...LA CORTE/CERU
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
759 AM EDT THU MAY 9 2013
.SYNOPSIS...
UPPER LEVEL LOW PRESSURE CENTERED WILL DRIFT SLOWLY NORTHEAST
INTO THE CATSKILL REGION OF SOUTHEASTERN NEW YORK LATER TODAY.
WEAK HIGH PRESSURE WILL BUILD EAST OVER THE COMMONWEALTH THIS
AFTERNOON INTO EARLY FRIDAY. MILDER...AND MORE HUMID AIR WILL PUSH
INTO THE REGION FRIDAY AFTERNOON THROUGH SATURDAY...AHEAD OF A
STRONG COLD FRONT THAT WILL BRING UNSEASONABLY COOL AIR TO THE
REGION LATER IN THE WEEKEND INTO EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AN UPPER LOW...CENTERED OVER EASTERN PA EARLY TODAY WILL DRIFT
SLOWLY TO THE NE TODAY. HIGH RES SHORT RANGE MODELS HIGHLIGHT THE
NW QUAD OF THIS LOW FOR ENHANCED PRECIP TODAY AS THE SYSTEM LIFTS
NORTHEAST AND MUCH OF THE REGION COMES UNDER THE AREA OF BEST
FRONTOGENETIC FORCING IN THE BACK-SIDE DEFORMATIONS ZONE.
RAIN IS ALREADY FALLING IN A LOOSELY ORGANIZED BAND FROM THE LOWER
SUSQ VALLEY NNW UP INTO SWRN NY STATE. RUC SHOWS THE BEST FGEN
FORCING FOCUSING OVER THE AREA OF THE FLASH FLOOD WATCH INTO THE
AFTERNOON...WHILE ALSO GENERATING SOME MODEST AMOUNT OF
INSTABILITY UNDER THE CHILLY TEMPS ALOFT.
EXPECT THE RAIN TO CONTINUE THROUGH THE MID TO LATE MORNING HOURS
WITH AN AVERAGE OF 1-3 TENTHS OF RAINFALL.
FROM EARLIER...
DURING THE LATE MORNING AND AFTERNOON HOURS...WILL BE CLOSELY
MONITORING HIGH RES MODEL AND RADAR TRENDS FOR POTENTIAL
NARROW/QUASI STNRY BANDS OF HEAVY SHOWERS AND LOW-TOPPED TSRA
SETTING UP ON A NW-SE AXIS IN THE WELL ALIGNED NW FLOW JUST TO THE
WEST AND SW OF THE DEPARTING UPPER LOW. A NARROW RIBBON OF
RELATIVELY HIGHER PWAT AIR /JUST OVER AND INCH/ WILL BE SHIFTING
SLOWLY EAST FROM THE ALLEGHENIES...TO THE CENTRAL MTNS AND SUSQ
VALLEY BY EARLY THIS EVENING.
MIXED LAYER...MU CAPE VALUES THIS RAMP UP TO 500-900 J/KG DURING THE
MIDDAY AND AFTERNOON HOURS /WITH HIGHER CAPES OF 1000-1500 J/KG
LIKELY DEVELOPING ACROSS SWRN PENN AND INTO THE LAUREL HIGHLANDS.
THIS THIN CAPE WILL ALLOW PARCELS TO ASCEND TO 5-8 KFT ABOVE THE
-20C LEVEL LEADING TO SOME LOW-TOPPED TSRA WITH SMALL HAIL AS THE
WET BULB ZERO LEVEL WILL BE VERY LOW...AND ONLY AROUND 7 KFT AGL.
POPS TODAY WILL BE NEAR 100 PERCENT FOR MUCH OF CENTRAL AND NRN
PA...WITH SURROUNDING AREAS IN THE LIKELY CATEGORY FOR SHOWERS AND
SCATTERED TSRA GIVEN THE ABOVE FACTORS. ALTHOUGH BASIN AVERAGE
RAINFALL TODAY WILL BE JUST A TENTH TO ONE QUARTER OF AN INCH IN
MANY LOCATIONS...THERE WILL LIKELY BE A FEW NARROW BANDS OF HEAVY
RAINFALL EXCEEDING ONE INCH ONCE AGAIN TODAY.
PINNING DOWN THE EXACT LOCATION OF THESE MESOSCALE FEATURES IS
QUITE DIFFICULT...BUT HIGH RES MODEL LOW-MID LEVEL FRONTOGENESIS
AND MOISTURE CONVERGENCE INDICATES THE BEST CHANCE FOR HEAVIER
RAINFALL WILL BE ACROSS THE NCENT MTNS AND SUSQ VALLEY...IN CLOSE
PROXIMITY TO WHERE WE HAD LOCALLY OVER 2 INCHES WEDNESDAY. AS A
RESULT...A FLASH FLOOD WATCH WAS POSTED FOR TODAY /14Z-00Z FRIDAY
FOR 11 COUNTIES IN THE AFOREMENTIONED AREA OF HEAVY RAIN/.
DESPITE BREAKS OF SUNSHINE CLOUDS SHOULD PREDOMINATE TODAY. MDL 8H
TEMPS ARND 9C ARE SUPPORTIVE OF HIGHS FROM THE U60S ACROSS THE
ALLEGHENIES...TO THE L-M70S OVR THE SUSQ VALLEY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM FRIDAY/...
TONIGHT WILL SEE A STEADILY DECREASING TREND IN THE SHOWERS EARLY
ON...FOLLOWED BY SOME PARTIAL CLEARING AND LIGHT WIND LEADING TO THE
LIKELIHOOD OF FAIRLY WIDESPREAD FOG. MIN TEMPS WILL BE IN THE MID
40S TO LOWER 50S.
FRIDAY WILL SEE A RETURN OF MOISTURE AND WARMER TEMPS AS A DEEP
SWRLY FLOW DEVELOPS AHEAD OF A SLOW-MOVING/DYING COLD FRONT HEADING
EAST FORM THE OHIO VALLEY. 0-3KM HELICITY PEAKS BETWEEN 150 AND 250
M2/S2 FRIDAY AFTERNOON NEAR AND JUST TO THE SOUTH OF A WARM FRONT
AND SSWRLY 850 MB JET OF 30-35 KTS. POCKETS OF ML MU CAPE EXCEEDING
1500 J/KG WILL DEVELOPS IN WARMER AND MORE HUMID AIR MASS...AND
ACROSS THE FAR NW FRIDAY AFTERNOON /THEN OVER THE FAR SE TWD 00Z
SAT/...0-1KM EHI VALUES ARE EXPECTED TO RISE TO BETWEEN 1-1.5 MS/S2
SUPPORTING ROTATING UPDRAFTS IN SOME OF THE TSRA. SPC/S DAY 2
OUTLOOK TARGETS MUCH OF THE CWA FOR A SLIGHT RISK OF SVR.
THE BIG QUESTION/UNCERTAINTY...AS USUAL...SURROUNDING THE EXTENT OF
THE SVR THREAT FRIDAY AFTERNOON AND EVENING WILL BE THE AMOUNT OF
SUNSHINE/INSTABILITY THAT WILL FORM IN THE WARM SECTOR JUST AHEAD OF
THE INCREASING LARGE SCALE FORCING AND APPROACHING SFC
CFRONT.
HIGH TEMPS FRIDAY WILL RANGE FROM AROUND 70F ACROSS THE NW MTNS...TO
A BALMY 75-80 DEGREES FROM THE CENTRAL MTNS...SE TO THE LOWER SUSQ
VALLEY.
&&
.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
NOT A LOT OF CHANGE FOR FRIDAY NIGHT INTO SAT NIGHT. SERIES OF
COLD FRONTS MOVE ACROSS. ONE FRONT EARLY SAT...THEN ANOTHER
SATURDAY NIGHT. THE REAL COLD AIR WILL COME IN LATER
SUNDAY...BEHIND THE UPPER LVL FRONT. NEAR RECORD COLD LIKELY FROM
LATE SUNDAY INTO TUE AM. FROST AND FREEZE ISSUES WILL BE LIKELY.
AS THE HIGH MOVES TO TH SE LATE TUE...MODELS SHOW A STRONG
WESTERLY FLOW OF VERY WARM AIR FOR WED INTO THU... BEFORE ANOTHER
COLD SPELL LATER IN THE WEEK. PATTERN SUPPORT STRONG TO SEVERE
STORMS POSSIBLE WITH WARM FRONT...DID PUT LOW POPS IN ALONG THE NY
BORDER.
DID NOT GO TO CRAZY WITH MAX TEMPS AT THIS POINT...BUT COULD SEE
SOME MID 80S.
&&
.AVIATION /12Z THURSDAY THROUGH MONDAY/...
A LOW PRESSURE SYSTEM MOVING THROUGH PA IS FORECAST TO SLOWLY
LIFT NORTHEAST INTO NEW ENGLAND THROUGH FRIDAY. SCATTERED SHOWERS
MOVING AROUND THIS LOW WILL CONTINUE THROUGH THE MORNING AND
AFTERNOON. THE SHOWERS WILL BE MAINLY LIGHT THROUGH THE MORNING
HOURS...INTENSIFYING BY LATE MORNING AND AFTERNOON DUE TO
CONVECTION. DUE TO THE COPIOUS MOISTURE...EXPECT PATCHY
FOG/MIST...ESPECIALLY AT MDT AND LNS AND REGIONS WHERE MORE
WIDESPREAD PRECIPITATION FELL YESTERDAY...THROUGH 14Z. EXPECT
MVFR/IFR...WITH SOME SITES POTENTIALLY REACHING LIFR...VSBYS THIS
MORNING. ANY FOG/MIST WILL LIFT/DISSIPATE BY MID MORNING...WITH
SHOWERS CONTINUING AND THUNDERSTORMS POSSIBLE IN AFTERNOON. IFR
CIGS AND VSBYS ARE POSSIBLE IN AND AROUND THUNDERSTORM
ACTIVITY...WHERE THE HIGHEST PROBABILITIES WILL BE AT UNV AND IPT
TAF SITES.
AS THE LOW MOVES TO THE NORTHEAST THE SHOWERS AND THUNDERSTORMS
WILL TAPER OFF AND SKIES WILL BEGIN TO CLEAR TONIGHT AS WEAK HIGH
PRESSURE BUILDS OVER THE COMMONWEALTH BRINGING MOSTLY VFR FLYING
CONDITIONS.
.OUTLOOK...
FRI...COLD FRONT MOVES THROUGH. SCT SHOWERS AND PERHAPS A
THUNDERSTORM LATE ACCOMPANIED BY LOCAL MVFR CONDITIONS.
SAT...MORE SHOWERS POSSIBLE WITH ANOTHER COLD FRONT.
SUN...SHOWERS EARLY...THEN IMPROVING CONDITIONS.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH THROUGH THIS EVENING FOR PAZ006-012-037-041-
045-046-049>052-056-057-063.
&&
$$
SYNOPSIS...LA CORTE/LAMBERT
NEAR TERM...LA CORTE/LAMBERT
SHORT TERM...FITZGERALD/LAMBERT
LONG TERM...MARTIN
AVIATION...CERU/GARTNER
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
753 AM EDT THU MAY 9 2013
.SYNOPSIS...
UPPER LEVEL LOW PRESSURE CENTERED ACROSS THE LOWER SUSQUEHANNA
VALLEY EARLY TODAY WILL DRIFT SLOWLY NORTHEAST INTO THE CATSKILL
REGION OF SOUTHEASTERN NEW YORK LATER TODAY. WEAK HIGH PRESSURE WILL
BUILD EAST OVER THE COMMONWEALTH THIS AFTERNOON INTO EARLY FRIDAY.
MILDER...AND MORE HUMID AIR WILL PUSH INTO THE REGION FRIDAY
AFTERNOON THROUGH SATURDAY...AHEAD OF A STRONG COLD FRONT THAT WILL
BRING UNSEASONABLY COOL AIR TO THE REGION LATER IN THE WEEKEND INTO
EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
SLOWLY WEAKENING UPPER LOW...CENTERED OVER THE MIDDLE SUSQ VALLEY
AT 09Z WILL DRIFT SLOWLY TO THE NE TODAY. 08/21Z AND 09/03Z SREF...
AND THE LATEST HRRR GUIDANCE INDICATES THAT THE CURRENT...
SLOWLY EXPANDING AREA OF SHOWERS ACRS THE CENTRAL AND NRN MTNS
WILL CONTINUE TO SPREAD SOUTH AND EAST THROUGH THE MID TO LATE
MORNING HOURS /TWD THE KIPT...KSEG AND KMDT AREAS/. EXPECT AN
AVERAGE OF 1-3 TENTHS OF RAINFALL WITH SOME LOCALLY HEAVIER
AMOUNTS POSSIBLE BETWEEN 09Z-14Z. THE BULK OF THE SHOWERS
THROUGH 14Z SHOULD STAY JUST TO THE WEST AND SOUTH OF KIPT...
AND ALSO JUST NORTH OF KAOO.
WET GROUND OVR MUCH OF THE AREA...COMBINED WITH A NEARLY CALM WIND
AND A FEW BREAKS IN THE OVERCAST...SHOULD RESULT IN AREAS OF FOG
THROUGH THE MID MORNING HOURS. LOW TEMPS AROUND DAYBREAK SHOULD
RANGE FROM THE U40S ACROSS THE ALLEGHENY PLATEAU...TO THE L50S
ELSEWHERE.
DURING THE LATE MORNING AND AFTERNOON HOURS...WILL BE CLOSELY
MONITORING HIGH RES MODEL AND RADAR TRENDS FOR POTENTIAL NARROW/QUASI
STNRY BANDS OF HEAVY SHOWERS AND LOW-TOPPED TSRA SETTING UP ON A
NW-SE AXIS IN THE WELL ALIGNED NW FLOW JUST TO THE WEST AND SW OF
THE DEPARTING UPPER LOW. A NARROW RIBBON OF RELATIVELY HIGHER PWAT
AIR /JUST OVER AND INCH/ WILL BE SHIFTING SLOWLY EAST FROM THE
ALLEGHENIES...TO THE CENTRAL MTNS AND SUSQ VALLEY BY EARLY THIS
EVENING.
MIXED LAYER...MU CAPE VALUES THIS RAMP UP TO 500-900 J/KG DURING THE
MIDDAY AND AFTERNOON HOURS /WITH HIGHER CAPES OF 1000-1500 J/KG
LIKELY DEVELOPING ACROSS SWRN PENN AND INTO THE LAUREL HIGHLANDS.
THIS THIN CAPE WILL ALLOW PARCELS TO ASCEND TO 5-8 KFT ABOVE THE
-20C LEVEL LEADING TO SOME LOW-TOPPED TSRA WITH SMALL HAIL AS THE
WET BULB ZERO LEVEL WILL BE VERY LOW...AND ONLY AROUND 7 KFT AGL.
POPS TODAY WILL BE NEAR 100 PERCENT FOR MUCH OF CENTRAL AND NRN
PA...WITH SURROUNDING AREAS IN THE LIKELY CATEGORY FOR SHOWERS AND
SCATTERED TSRA GIVEN THE ABOVE FACTORS. ALTHOUGH BASIN AVERAGE
RAINFALL TODAY WILL BE JUST A TENTH TO ONE QUARTER OF AN INCH IN
MANY LOCATIONS...THERE WILL LIKELY BE A FEW NARROW BANDS OF HEAVY
RAINFALL EXCEEDING ONE INCH ONCE AGAIN TODAY.
PINNING DOWN THE EXACT LOCATION OF THESE MESOSCALE FEATURES IS
QUITE DIFFICULT...BUT HIGH RES MODEL LOW-MID LEVEL FRONTOGENEISIS
AND MOISTURE CONVERGENCE INDICATES THE BEST CHANCE FOR HEAVIER
RAINFALL WILL BE ACROSS THE NCENT MTNS AND SUSQ VALLEY...IN CLOSE
PROXIMITY TO WHERE WE HAD LOCALLY OVER 2 INCHES WEDNESDAY. AS A
RESULT...A FLASH FLOOD WATCH WAS POSTED FOR TODAY /14Z-00Z FRIDAY
FOR 11 COUNTIES IN THE AFOREMENTIONED AREA OF HEAVY RAIN/.
DESPITE BREAKS OF SUNSHINE CLOUDS SHOULD PREDOMINATE TODAY. MDL 8H
TEMPS ARND 9C ARE SUPPORTIVE OF HIGHS FROM THE U60S ACROSS THE
ALLEGHENIES...TO THE L-M70S OVR THE SUSQ VALLEY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM FRIDAY/...
TONIGHT WILL SEE A STEADILY DECREASING TREND IN THE SHOWERS EARLY
ON...FOLLOWED BY SOME PARTIAL CLEARING AND LIGHT WIND LEADING TO THE
LIKELIHOOD OF FAIRLY WIDESPREAD FOG. MIN TEMPS WILL BE IN THE MID
40S TO LOWER 50S.
FRIDAY WILL SEE A RETURN OF MOISTURE AND WARMER TEMPS AS A DEEP
SWRLY FLOW DEVELOPS AHEAD OF A SLOW-MOVING/DYING COLD FRONT HEADING
EAST FORM THE OHIO VALLEY. 0-3KM HELICITY PEAKS BETWEEN 150 AND 250
M2/S2 FRIDAY AFTERNOON NEAR AND JUST TO THE SOUTH OF A WARM FRONT
AND SSWRLY 850 MB JET OF 30-35 KTS. POCKETS OF ML MU CAPE EXCEEDING
1500 J/KG WILL DEVELOPS IN WARMER AND MORE HUMID AIR MASS...AND
ACROSS THE FAR NW FRIDAY AFTERNOON /THEN OVER THE FAR SE TWD 00Z
SAT/...0-1KM EHI VALUES ARE EXPECTED TO RISE TO BETWEEN 1-1.5 MS/S2
SUPPORTING ROTATING UPDRAFTS IN SOME OF THE TSRA. SPC/S DAY 2
OUTLOOK TARGETS MUCH OF THE CWA FOR A SLIGHT RISK OF SVR.
THE BIG QUESTION/UNCERTAINTY...AS USUAL...SURROUNDING THE EXTENT OF
THE SVR THREAT FRIDAY AFTERNOON AND EVENING WILL BE THE AMOUNT OF
SUNSHINE/INSTABILITY THAT WILL FORM IN THE WARM SECTOR JUST AHEAD OF
THE INCREASING LARGE SCALE FORCING AND APPROACHING SFC
CFRONT.
HIGH TEMPS FRIDAY WILL RANGE FROM AROUND 70F ACROSS THE NW MTNS...TO
A BALMY 75-80 DEGREES FROM THE CENTRAL MTNS...SE TO THE LOWER SUSQ
VALLEY.
&&
.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
NOT A LOT OF CHANGE FOR FRIDAY NIGHT INTO SAT NIGHT. SERIES OF
COLD FRONTS MOVE ACROSS. ONE FRONT EARLY SAT...THEN ANOTHER
SATURDAY NIGHT. THE REAL COLD AIR WILL COME IN LATER
SUNDAY...BEHIND THE UPPER LVL FRONT. NEAR RECORD COLD LIKELY FROM
LATE SUNDAY INTO TUE AM. FROST AND FREEZE ISSUES WILL BE LIKELY.
AS THE HIGH MOVES TO TH SE LATE TUE...MODELS SHOW A STRONG
WESTERLY FLOW OF VERY WARM AIR FOR WED INTO THU... BEFORE ANOTHER
COLD SPELL LATER IN THE WEEK. PATTERN SUPPORT STRONG TO SEVERE
STORMS POSSIBLE WITH WARM FRONT...DID PUT LOW POPS IN ALONG THE NY
BORDER.
DID NOT GO TO CRAZY WITH MAX TEMPS AT THIS POINT...BUT COULD SEE
SOME MID 80S.
&&
.AVIATION /12Z THURSDAY THROUGH MONDAY/...
A LOW PRESSURE SYSTEM MOVING THROUGH PA IS FORECAST TO SLOWLY
LIFT NORTHEAST INTO NEW ENGLAND THROUGH FRIDAY. SCATTERED SHOWERS
MOVING AROUND THIS LOW WILL CONTINUE THROUGH THE MORNING AND
AFTERNOON. THE SHOWERS WILL BE MAINLY LIGHT THROUGH THE MORNING
HOURS...INTENSIFYING BY LATE MORNING AND AFTERNOON DUE TO
CONVECTION. DUE TO THE COPIOUS MOISTURE...EXPECT PATCHY
FOG/MIST...ESPECIALLY AT MDT AND LNS AND REGIONS WHERE MORE
WIDESPREAD PRECIPITATION FELL YESTERDAY...THROUGH 14Z. EXPECT
MVFR/IFR...WITH SOME SITES POTENTIALLY REACHING LIFR...VSBYS THIS
MORNING. ANY FOG/MIST WILL LIFT/DISSIPATE BY MID MORNING...WITH
SHOWERS CONTINUING AND THUNDERSTORMS POSSIBLE IN AFTERNOON. IFR
CIGS AND VSBYS ARE POSSIBLE IN AND AROUND THUNDERSTORM
ACTIVITY...WHERE THE HIGHEST PROBABILITIES WILL BE AT UNV AND IPT
TAF SITES.
AS THE LOW MOVES TO THE NORTHEAST THE SHOWERS AND THUNDERSTORMS
WILL TAPER OFF AND SKIES WILL BEGIN TO CLEAR TONIGHT AS WEAK HIGH
PRESSURE BUILDS OVER THE COMMONWEALTH BRINGING MOSTLY VFR FLYING
CONDITIONS.
.OUTLOOK...
FRI...COLD FRONT MOVES THROUGH. SCT SHOWERS AND PERHAPS A
THUNDERSTORM LATE ACCOMPANIED BY LOCAL MVFR CONDITIONS.
SAT...MORE SHOWERS POSSIBLE WITH ANOTHER COLD FRONT.
SUN...SHOWERS EARLY...THEN IMPROVING CONDITIONS.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH THROUGH THIS EVENING FOR PAZ006-012-037-041-
045-046-049>052-056-057-063.
&&
$$
SYNOPSIS...LA CORTE/LAMBERT
NEAR TERM...LA CORTE/LAMBERT
SHORT TERM...FITZGERALD/LAMBERT
LONG TERM...MARTIN
AVIATION...CERU/GARTNER
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
558 AM EDT THU MAY 9 2013
.SYNOPSIS...
UPPER LEVEL LOW PRESSURE CENTERED ACROSS THE LOWER SUSQUEHANNA
VALLEY EARLY TODAY WILL DRIFT SLOWLY NORTHEAST INTO THE CATSKILL
REGION OF SOUTHEASTERN NEW YORK LATER TODAY. WEAK HIGH PRESSURE WILL
BUILD EAST OVER THE COMMONWEALTH THIS AFTERNOON INTO EARLY FRIDAY.
MILDER...AND MORE HUMID AIR WILL PUSH INTO THE REGION FRIDAY
AFTERNOON THROUGH SATURDAY...AHEAD OF A STRONG COLD FRONT THAT WILL
BRING UNSEASONABLY COOL AIR TO THE REGION LATER IN THE WEEKEND INTO
EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
SLOWLY WEAKENING UPPER LOW...CENTERED OVER THE MIDDLE SUSQ VALLEY
AT 09Z WILL DRIFT SLOWLY TO THE NE TODAY. 08/21Z AND 09/03Z SREF...
AND THE LATEST HRRR GUIDANCE INDICATES THAT THE CURRENT...
SLOWLY EXPANDING AREA OF SHOWERS ACRS THE CENTRAL AND NRN MTNS
WILL CONTINUE TO SPREAD SOUTH AND EAST THROUGH THE MID TO LATE
MORNING HOURS /TWD THE KIPT...KSEG AND KMDT AREAS/. EXPECT AN
AVERAGE OF 1-3 TENTHS OF RAINFALL WITH SOME LOCALLY HEAVIER
AMOUNTS POSSIBLE BETWEEN 09Z-14Z. THE BULK OF THE SHOWERS
THROUGH 14Z SHOULD STAY JUST TO THE WEST AND SOUTH OF KIPT...
AND ALSO JUST NORTH OF KAOO.
WET GROUND OVR MUCH OF THE AREA...COMBINED WITH A NEARLY CALM WIND
AND A FEW BREAKS IN THE OVERCAST...SHOULD RESULT IN AREAS OF FOG
THROUGH THE MID MORNING HOURS. LOW TEMPS AROUND DAYBREAK SHOULD
RANGE FROM THE U40S ACROSS THE ALLEGHENY PLATEAU...TO THE L50S
ELSEWHERE.
DURING THE LATE MORNING AND AFTERNOON HOURS...WILL BE CLOSELY
MONITORING HIGH RES MODEL AND RADAR TRENDS FOR POTENTIAL NARROW/QUASI
STNRY BANDS OF HEAVY SHOWERS AND LOW-TOPPED TSRA SETTING UP ON A
NW-SE AXIS IN THE WELL ALIGNED NW FLOW JUST TO THE WEST AND SW OF
THE DEPARTING UPPER LOW. A NARROW RIBBON OF RELATIVELY HIGHER PWAT
AIR /JUST OVER AND INCH/ WILL BE SHIFTING SLOWLY EAST FROM THE
ALLEGHENIES...TO THE CENTRAL MTNS AND SUSQ VALLEY BY EARLY THIS
EVENING.
MIXED LAYER...MU CAPE VALUES THIS RAMP UP TO 500-900 J/KG DURING THE
MIDDAY AND AFTERNOON HOURS /WITH HIGHER CAPES OF 1000-1500 J/KG
LIKELY DEVELOPING ACROSS SWRN PENN AND INTO THE LAUREL HIGHLANDS.
THIS THIN CAPE WILL ALLOW PARCELS TO ASCEND TO 5-8 KFT ABOVE THE
-20C LEVEL LEADING TO SOME LOW-TOPPED TSRA WITH SMALL HAIL AS THE
WET BULB ZERO LEVEL WILL BE VERY LOW...AND ONLY AROUND 7 KFT AGL.
POPS TODAY WILL BE NEAR 100 PERCENT FOR MUCH OF CENTRAL AND NRN
PA...WITH SURROUNDING AREAS IN THE LIKELY CATEGORY FOR SHOWERS AND
SCATTERED TSRA GIVEN THE ABOVE FACTORS. ALTHOUGH BASIN AVERAGE
RAINFALL TODAY WILL BE JUST A TENTH TO ONE QUARTER OF AN INCH IN
MANY LOCATIONS...THERE WILL LIKELY BE A FEW NARROW BANDS OF HEAVY
RAINFALL EXCEEDING ONE INCH ONCE AGAIN TODAY.
PINNING DOWN THE EXACT LOCATION OF THESE MESOSCALE FEATURES IS
QUITE DIFFICULT...BUT HIGH RES MODEL LOW-MID LEVEL FRONTOGENEISIS
AND MOISTURE CONVERGENCE INDICATES THE BEST CHANCE FOR HEAVIER
RAINFALL WILL BE ACROSS THE NCENT MTNS AND SUSQ VALLEY...IN CLOSE
PROXIMITY TO WHERE WE HAD LOCALLY OVER 2 INCHES WEDNESDAY. AS A
RESULT...A FLASH FLOOD WATCH WAS POSTED FOR TODAY /14Z-00Z FRIDAY
FOR 11 COUNTIES IN THE AFOREMENTIONED AREA OF HEAVY RAIN/.
DESPITE BREAKS OF SUNSHINE CLOUDS SHOULD PREDOMINATE TODAY. MDL 8H
TEMPS ARND 9C ARE SUPPORTIVE OF HIGHS FROM THE U60S ACROSS THE
ALLEGHENIES...TO THE L-M70S OVR THE SUSQ VALLEY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM FRIDAY/...
TONIGHT WILL SEE A STEADILY DECREASING TREND IN THE SHOWERS EARLY
ON...FOLLOWED BY SOME PARTIAL CLEARING AND LIGHT WIND LEADING TO THE
LIKELIHOOD OF FAIRLY WIDESPREAD FOG. MIN TEMPS WILL BE IN THE MID
40S TO LOWER 50S.
FRIDAY WILL SEE A RETURN OF MOISTURE AND WARMER TEMPS AS A DEEP
SWRLY FLOW DEVELOPS AHEAD OF A SLOW-MOVING/DYING COLD FRONT HEADING
EAST FORM THE OHIO VALLEY. 0-3KM HELICITY PEAKS BETWEEN 150 AND 250
M2/S2 FRIDAY AFTERNOON NEAR AND JUST TO THE SOUTH OF A WARM FRONT
AND SSWRLY 850 MB JET OF 30-35 KTS. POCKETS OF ML MU CAPE EXCEEDING
1500 J/KG WILL DEVELOPS IN WARMER AND MORE HUMID AIR MASS...AND
ACROSS THE FAR NW FRIDAY AFTERNOON /THEN OVER THE FAR SE TWD 00Z
SAT/...0-1KM EHI VALUES ARE EXPECTED TO RISE TO BETWEEN 1-1.5 MS/S2
SUPPORTING ROTATING UPDRAFTS IN SOME OF THE TSRA. SPC/S DAY 2
OUTLOOK TARGETS MUCH OF THE CWA FOR A SLIGHT RISK OF SVR.
THE BIG QUESTION/UNCERTAINTY...AS USUAL...SURROUNDING THE EXTENT OF
THE SVR THREAT FRIDAY AFTERNOON AND EVENING WILL BE THE AMOUNT OF
SUNSHINE/INSTABILITY THAT WILL FORM IN THE WARM SECTOR JUST AHEAD OF
THE INCREASING LARGE SCALE FORCING AND APPROACHING SFC
CFRONT.
HIGH TEMPS FRIDAY WILL RANGE FROM AROUND 70F ACROSS THE NW MTNS...TO
A BALMY 75-80 DEGREES FROM THE CENTRAL MTNS...SE TO THE LOWER SUSQ
VALLEY.
&&
.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
NOT A LOT OF CHANGE FOR FRIDAY NIGHT INTO SAT NIGHT. SERIES OF
COLD FRONTS MOVE ACROSS. ONE FRONT EARLY SAT...THEN ANOTHER
SATURDAY NIGHT. THE REAL COLD AIR WILL COME IN LATER
SUNDAY...BEHIND THE UPPER LVL FRONT. NEAR RECORD COLD LIKELY FROM
LATE SUNDAY INTO TUE AM. FROST AND FREEZE ISSUES WILL BE LIKELY.
AS THE HIGH MOVES TO TH SE LATE TUE...MODELS SHOW A STRONG
WESTERLY FLOW OF VERY WARM AIR FOR WED INTO THU... BEFORE ANOTHER
COLD SPELL LATER IN THE WEEK. PATTERN SUPPORT STRONG TO SEVERE
STORMS POSSIBLE WITH WARM FRONT...DID PUT LOW POPS IN ALONG THE NY
BORDER.
DID NOT GO TO CRAZY WITH MAX TEMPS AT THIS POINT...BUT COULD SEE
SOME MID 80S.
&&
.AVIATION /10Z THURSDAY THROUGH MONDAY/...
A LOW PRESSURE SYSTEM MOVING THROUGH PA IS FORECAST TO SLOWLY
LIFT NORTHEAST INTO NEW ENGLAND THROUGH FRIDAY. SCATTERED SHOWERS
MOVING AROUND THIS LOW WILL CONTINUE THROUGH THE MORNING AND
AFTERNOON. THE SHOWERS WILL BE MAINLY LIGHT THROUGH THE MORNING
HOURS...INTENSIFYING BY LATE MORNING AND AFTERNOON DUE TO
CONVECTION. DUE TO THE COPIOUS MOISTURE...EXPECT PATCHY
FOG/MIST...ESPECIALLY AT MDT AND LNS AND REGIONS WHERE MORE
WIDESPREAD PRECIPITATION FELL YESTERDAY...THROUGH 12Z. EXPECT
MVFR/IFR...WITH SOME SITES POTENTIALLY REACHING LIFR... VSBYS
THIS MORNING. ANY FOG/MIST WILL LIFT/DISSIPATE BY MID
MORNING...WITH SHOWERS CONTINUING AND THUNDERSTORMS POSSIBLE IN
AFTERNOON. IFR CIGS AND VSBYS ARE POSSIBLE IN AND AROUND
THUNDERSTORM ACTIVITY...WHERE THE HIGHEST PROBABILITIES WILL BE AT
UNV AND IPT.
WEAK HIGH PRESSURE WILL BUILD EAST OVER THE COMMONWEALTH LATE
THIS AFTERNOON INTO EARLY FRIDAY...BRINGING MOSTLY VFR FLYING
CONDITIONS.
.OUTLOOK...
FRI...COLD FRONT MOVES THROUGH. SCT SHOWERS AND PERHAPS A
THUNDERSTORM LATE ACCOMPANIED BY LOCAL MVFR CONDITIONS.
SAT...MORE SHOWERS POSSIBLE WITH ANOTHER COLD FRONT.
SUN...SHOWERS EARLY...THEN IMPROVING CONDITIONS.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH FROM 10 AM EDT THIS MORNING THROUGH THIS
EVENING FOR PAZ006-012-037-041-045-046-049>052-056-057-063.
&&
$$
SYNOPSIS...LAMBERT
NEAR TERM...LAMBERT
SHORT TERM...FITZGERALD/LAMBERT
LONG TERM...MARTIN
AVIATION...CERU/GARTNER
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
545 AM EDT THU MAY 9 2013
.SYNOPSIS...
UPPER LEVEL LOW PRESSURE CENTERED ACROSS THE LOWER SUSQUEHANNA
VALLEY EARLY TODAY WILL DRIFT SLOWLY NORTHEAST INTO THE CATSKILL
REGION OF SOUTHEASTERN NEW YORK LATER TODAY. WEAK HIGH PRESSURE WILL
BUILD EAST OVER THE COMMONWEALTH THIS AFTERNOON INTO EARLY FRIDAY.
MILDER...AND MORE HUMID AIR WILL PUSH INTO THE REGION FRIDAY
AFTERNOON THROUGH SATURDAY...AHEAD OF A STRONG COLD FRONT THAT WILL
BRING UNSEASONABLY COOL AIR TO THE REGION LATER IN THE WEEKEND INTO
EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
SLOWLY WEAKENING UPPER LOW...CENTERED OVER THE MIDDLE SUSQ VALLEY
AT 09Z WILL DRIFT SLOWLY TO THE NE TODAY. 08/21Z AND 09/03Z SREF...
AND THE LATEST HRRR GUIDANCE INDICATES THAT THE CURRENT...
SLOWLY EXPANDING AREA OF SHOWERS ACRS THE CENTRAL AND NRN MTNS
WILL CONTINUE TO SPREAD SOUTH AND EAST THROUGH THE MID TO LATE
MORNING HOURS /TWD THE KIPT...KSEG AND KMDT AREAS/. EXPECT AN
AVERAGE OF 1-3 TENTHS OF RAINFALL WITH SOME LOCALLY HEAVIER
AMOUNTS POSSIBLE BETWEEN 09Z-14Z. THE BULK OF THE SHOWERS
THROUGH 14Z SHOULD STAY JUST TO THE WEST AND SOUTH OF KIPT...
AND ALSO JUST NORTH OF KAOO.
WET GROUND OVR MUCH OF THE AREA...COMBINED WITH A NEARLY CALM WIND
AND A FEW BREAKS IN THE OVERCAST...SHOULD RESULT IN AREAS OF FOG
THROUGH THE MID MORNING HOURS. LOW TEMPS AROUND DAYBREAK SHOULD
RANGE FROM THE U40S ACROSS THE ALLEGHENY PLATEAU...TO THE L50S
ELSEWHERE.
DURING THE LATE MORNING AND AFTERNOON HOURS...WILL BE CLOSELY
MONITORING HIGH RES MODEL AND RADAR TRENDS FOR POTENTIAL NARROW/QUASI
STNRY BANDS OF HEAVY SHOWERS AND LOW-TOPPED TSRA SETTING UP ON A
NW-SE AXIS IN THE WELL ALIGNED NW FLOW JUST TO THE WEST AND SW OF
THE DEPARTING UPPER LOW. A NARROW RIBBON OF RELATIVELY HIGHER PWAT
AIR /JUST OVER AND INCH/ WILL BE SHIFTING SLOWLY EAST FROM THE
ALLEGHENIES...TO THE CENTRAL MTNS AND SUSQ VALLEY BY EARLY THIS
EVENING.
MIXED LAYER...MU CAPE VALUES THIS RAMP UP TO 500-900 J/KG DURING THE
MIDDAY AND AFTERNOON HOURS /WITH HIGHER CAPES OF 1000-1500 J/KG
LIKELY DEVELOPING ACROSS SWRN PENN AND INTO THE LAUREL HIGHLANDS.
THIS THIN CAPE WILL ALLOW PARCELS TO ASCEND TO 5-8 KFT ABOVE THE
-20C LEVEL LEADING TO SOME LOW-TOPPED TSRA WITH SMALL HAIL AS THE
WET BULB ZERO LEVEL WILL BE VERY LOW...AND ONLY AROUND 7 KFT AGL.
POPS TODAY WILL BE NEAR 100 PERCENT FOR MUCH OF CENTRAL AND NRN
PA...WITH SURROUNDING AREAS IN THE LIKELY CAEGORY FOR SHOWERS AND
SCATTERED TSRA GIVEN THE ABOVE FACTORS. ALTHOUGH BASIN AVERAGE
RAINFALL TODAY WILL BE JUST A TENTH TO ONE QUARTER OF AN INCH IN
MANY LOCATIONS...THERE WILL LIKELY BE A FEW NARROW BANDS OF HEAVY
RAINFALL EXCEEDING ONE INCH ONCE AGAIN TODAY.
PINNING DOWN THE EXACT LOCATION OF THESE MESOSCALE FEATURES IS
QUITE DIFFICULT...BUT HIGH RES MODEL LOW-MID LEVEL FRONTOGENEISIS
AND MOISTURE CONVERGENCE INDICATES THE BEST CHANCE FOR HEAVIER
RAINFALL WILL BE ACROSS THE NCENT MTNS AND SUSQ VALLEY...IN CLOSE
PROXIMITY TO WHERE WE HAD LOCALLY OVER 2 INCHES WEDNESDAY. AS A
RESULT...A FLASH FLODD WATCH WAS POSTED FOR TODAY /14Z-00Z FRIDAY
FOR 11 COUNTIES IN THE AFOREMENTIONED AREA OF HEAVY RAIN/.
DESPITE BREAKS OF SUNSHINE CLOUDS SHOULD PREDOMINATE TODAY. MDL 8H
TEMPS ARND 9C ARE SUPPORTIVE OF HIGHS FROM THE U60S ACROSS THE
ALLEGHENIES...TO THE L-M70S OVR THE SUSQ VALLEY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM FRIDAY/...
TONIGHT WILL SEE A STEADILY DECREASING TREND IN THE SHOWERS EARLY
ON...FOLLOWED BY SOME PARTIAL CLEARING AND LIGHT WIND LEADING TO THE
LIKELIHOOD OF FAIRLY WIDESPREAD FOG. MIN TEMPS WILL BE IN THE MID
40S TO LOWER 50S.
FRIDAY WILL SEE A RETURN OF MOISTURE AND WARMER TEMPS AS A DEEP
SWRLY FLOW DEVELOPS AHEAD OF A SLOW-MOVING/DYING COLD FRONT HEADING
EAST FORM THE OHIO VALLEY. 0-3KM HELICITY PEAKS BETWEEN 150 AND 250
M2/S2 FRIDAY AFTERNOON NEAR AND JUST TO THE SOUTH OF A WARM FRONT
AND SSWRLY 850 MB JET OF 30-35 KTS. POCKETS OF ML MU CAPE EXCEEDING
1500 J/KG WILL DEVELOPS IN WARMER AND MORE HUMID AIR MASS...AND
ACROSS THE FAR NW FRIDAY AFTERNOON /THEN OVER THE FAR SE TWD 00Z
SAT/...0-1KM EHI VALUES ARE EXPECTED TO RISE TO BETWEEN 1-1.5 MS/S2
SUPPORTING ROTATING UPDRAFTS IN SOME OF THE TSRA. SPC/S DAY 2
OUTLOOK TARGETS MUCH OF THE CWA FOR A SLIGHT RISK OF SVR.
THE BIG QUESTION/UNCERTAINTY...AS USUAL...SURROUNDING THE EXTENT OF
THE SVR THREAT FRIDAY AFTERNOON AND EVENING WILL BE THE AMOUNT OF
SUNSHINE/INSTABILITY THAT WILL FORM IN THE WARM SECTOR JUST AHEAD OF
THE INCREASING LARGE SCALE FORCING AND APPROACHING SFC
CFRONT.
HIGH TEMPS FRIDAY WILL RANGE FROM AROUND 70F ACROSS THE NW MTNS...TO
A BALMY 75-80 DEGREES FROM THE CENTRAL MTNS...SE TO THE LOWER SUSQ
VALLEY.
&&
.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
NOT A LOT OF CHANGE FOR FRIDAY NIGHT INTO SAT NIGHT. SERIES OF
COLD FRONTS MOVE ACROSS. ONE FRONT EARLY SAT...THEN ANOTHER
SATURDAY NIGHT. THE REAL COLD AIR WILL COME IN LATER
SUNDAY...BEHIND THE UPPER LVL FRONT. NEAR RECORD COLD LIKELY FROM
LATE SUNDAY INTO TUE AM. FROST AND FREEZE ISSUES WILL BE LIKELY.
AS THE HIGH MOVES TO TH SE LATE TUE...MODELS SHOW A STRONG
WESTERLY FLOW OF VERY WARM AIR FOR WED INTO THU... BEFORE ANOTHER
COLD SPELL LATER IN THE WEEK. PATTERN SUPPORT STRONG TO SEVERE
STORMS POSSIBLE WITH WARM FRONT...DID PUT LOW POPS IN ALONG THE NY
BORDER.
DID NOT GO TO CRAZY WITH MAX TEMPS AT THIS POINT...BUT COULD SEE
SOME MID 80S.
&&
.AVIATION /10Z THURSDAY THROUGH MONDAY/...
A LOW PRESSURE SYSTEM MOVING THROUGH PA IS FORECAST TO SLOWLY
LIFT NORTHEAST INTO NEW ENGLAND THROUGH FRIDAY. MAJOR CONVECTIVE
ACTIVITY HAS SUBSIDED...WITH ONLY SCATTERED SHOWERS MOVING FROM THE
NORTH...SPREADING OVER CENTRAL PA. DUE TO THE COPIOUS MOISTURE
THERE IS THE LIKELIHOOD OF FOG...WHICH WILL INCREASE AFTER
07Z...AND BE STRONGEST FROM 09-13Z...ESP OVER EASTERN TAF SITES
WHERE MORE WIDESPREAD RAINS FELL TODAY FROM MDT NORTH TO IPT.
EXPECT MVFR/IFR...WITH SOME SITES POTENTIALLY REACHING LIFR...
VSBYS THURSDAY MORNING.
WEAK HIGH PRESSURE WILL BUILD EAST OVER THE COMMONWEALTH LATE
THURSDAY AFTERNOON INTO EARLY FRIDAY...BRINGING MOSTLY VFR FLYING
CONDITIONS.
.OUTLOOK...
THU...WIDESPREAD MVFR/IFR IN MORNING FOG. THEN MAINLY VFR
CONDITIONS WITH MVFR SCATTERED SHOWERS AND ISOLATED TSTMS.
FRI...COLD FRONT MOVES THROUGH. SCT SHOWERS AND PERHAPS A
THUNDERSTORM LATE ACCOMPANIED BY LOCAL MVFR CONDITIONS.
SAT...MORE SHOWERS POSSIBLE WITH ANOTHER COLD FRONT.
SUN...SHOWERS EARLY...THEN IMPROVING CONDITIONS.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH FROM 10 AM EDT THIS MORNING THROUGH THIS
EVENING FOR PAZ006-012-037-041-045-046-049>052-056-057-063.
&&
$$
SYNOPSIS...LAMBERT
NEAR TERM...LAMBERT
SHORT TERM...LAMBERT
LONG TERM...MARTIN
AVIATION...CERU/GARTNER
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
1026 PM CDT FRI MAY 10 2013
.DISCUSSION...
MCS WAS CURRENTLY IN THE BURLESON AND BRAZOS COUNTY AREAS WILL
PUSH EASTWARD OVER THE NEXT FEW HOURS. LIKED THE LATEST HRRR 3 KM
MODEL WHICH MOVES THE RAIN AREA ALONG THE SURFACE BOUNDARY WHICH
SHOULD SLOWLY MOVE TOWARD THE COAST THROUGH THE REMAINDER OF
TONIGHT. SHOULD ALSO SEE DEVELOPMENT ALONG THE ACTUAL FRONT MOVING
SOUTHEASTWARD INTO THE NORTHERN COUNTIES OVER THE NEXT FEW HOURS
AS WELL. WITH PW/S BETWEEN 1.6 AND 1.8 INCHES...THE POSSIBILITY OF
LOCALLY HEAVY RAINFALL WILL CONTINUE. THINK THAT THE ISOLATED
SEVERE CHANCES ARE STILL POSSIBLE DUE MAINLY TO DAMAGING WIND
POTENTIAL. ISOLATED CASES OF LARGE HAIL IS STILL POSSIBLE DUE TO
THE COLDER AIRMASS ALOFT AS CAN BE SEEN BY 700 MB TEMPERATURES
AROUND 2 TO 3 DEGREES C AND 500 MB TEMPERATURES BETWEEN -10 AND
-15.
WITH THIS IN MIND...ADJUSTED THE RAIN CHANCES SLIGHTLY AND KEPT
THE FLASH FLOOD WATCH IN PLACE THROUGH THE REMAINDER OF TONIGHT.
ALSO ADJUSTED RAIN CHANCES SATURDAY MORNING TO ACCOUNT FOR THE
GOOD LIKELIHOOD THAT THE RAIN SYSTEM WILL MOVE ALONG AND OFF THE
COAST BY AROUND 12Z.
40
&&
.PREV DISCUSSION... /ISSUED 757 PM CDT FRI MAY 10 2013/
UPDATE...
RAISED RAIN CHANCES OVER THE WESTERN COUNTIES GENERALLY WEST OF A
LINE FROM MADISONVILLE TO HEMPSTEAD TO EDNA. A SURFACE BOUNDARY
WAS EVIDENT ON THE KGRK RADAR AND THUNDERSTORMS WERE DEVELOPING
ALONG THE LINE JUST WEST OF BURLESON AND WASHINGTON COUNTIES. THE
00Z SOUNDINGS SHOW THE BEST INSTABILITY IS LIKELY OVER THE WESTERN
AND SOUTHWESTERN SET OF COUNTIES...LIKELY ALONG AND SOUTH OF THE
SURFACE BOUNDARY. EARLY EVENING UPDATE GOING OUT AND WILL REASSESS
THE SITUATION AT LEAST ONCE MORE BETWEEN NOW AND 10 PM.
40
PREV DISCUSSION... /ISSUED 634 PM CDT FRI MAY 10 2013/
DISCUSSION...
00Z TAF DISCUSSION IN AVIATION SECTION.
AVIATION...
TOUGH SITUATION WITH ONGOING CONVECTION MOVING INTO C TX THIS
EVENING. NONE OF THE MESOSCALE MODELS REALLY HAVE A GOOD HANDLE ON
THE CURRENT ACTIVITY BUT THE HRRR AND LATEST WRF-ARW SEEM TO HAVE
DECENT TRENDS. WRF IS MUCH FASTER WITH THE CONVECTION BUT MAY HAVE
THE RIGHT AREAS. HRRR SEEMS TO HAVE BETTER TIMING BUT WEAKER. FOR
NOW TAFS WILL HAVE PREVAILING -SHRA/SHRA AFTER 04/05Z. COULD SEE
AN UPGRADE TO TS DEPENDING ON THE EVOLUTION OF THIS SYSTEM AND
WITH THE APPROACH OF A COLD FRONT. COLD FRONT CURRENTLY RUNS FROM
THE ARKLATEX INTO NW HILL COUNTRY. SHORT WAVE KICKING OFF CURRENT
ROUND OF CONVECTION IN C TX SHOULD ALSO MOVE INTO THE AREA AROUND
MIDNIGHT. ALL POINTS TO POSSIBILITY OF ORGANIZED CONVECTION BUT
UNCERTAIN AS TO WHERE IT WILL MAKE MOST IMPACT FOR SE TX
TERMINALS. MAY GET SOME IFR CIGS AS BOUNDARY LAYER COOLS WITH
HIGHER LOW LEVEL MOISTURE. MAY AT LEAST GET MIX OF SHOWERS AND
RESTRICTED VSBY AHEAD AND ALONG THE FRONT. EXPECT CIGS TO LIFT
LATE TOMORROW MORNING WITH FRONT PASSING.
39
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 66 81 58 82 58 / 60 30 10 10 10
HOUSTON (IAH) 67 80 63 83 60 / 60 40 10 10 10
GALVESTON (GLS) 70 78 69 80 67 / 60 50 20 10 10
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...FLASH FLOOD WATCH UNTIL 7 AM CDT SATURDAY FOR THE FOLLOWING
ZONES: FORT BEND...GRIMES...HARRIS...LIBERTY...MONTGOMERY...
POLK...SAN JACINTO...WALKER...WALLER.
GM...NONE.
&&
$$
DISCUSSION...40
AVIATION/MARINE...39
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
847 PM CDT FRI MAY 10 2013
.UPDATE...
SEE UPDATE DISCUSSION BELOW.
&&
.DISCUSSION...
UPDATED ZONES AND GRIDS TO REDUCE POPS TO SLGT CHC AND REMOVE
THUNDER FOR TONIGHT.
21
&&
.PREV DISCUSSION... /ISSUED 718 PM CDT FRI MAY 10 2013/
UPDATE...
SEE UPDATE DISCUSSION BELOW.
DISCUSSION...
UPDATED ZONES AND HAZARD GRID TO CANCEL SEVERE THUNDERSTORM WATCH
#156. ALSO...UPDATED HOURLY TEMPS DUE TO CURRENT READINGS IN THE
60S ACROSS MUCH OF THE AREA.
21
PREV DISCUSSION... /ISSUED 617 PM CDT FRI MAY 10 2013/
DISCUSSION...
SEE 00Z AVIATION DISCUSSION BELOW.
AVIATION...
SCATTERED TSTMS CURRENTLY OVER THE HEARTLAND AND NORTHWEST HILL
COUNTRY WILL EXIT THE AREA BY 01Z. ISOLD TSTMS WILL STILL BE
POSSIBLE THIS EVENING MAINLY SOUTH OF THE I-20 CORRIDOR. HAVE A
VCTS GOING AT THE KJCT AND KBBD TERMINALS THROUGH 02Z. OTHERWISE
MAINLY VFR CONDITIONS ARE EXPECTED THE NEXT 24 HOURS...WITH
ABUNDANT HIGH CLOUDS OVER WEST CENTRAL TEXAS. WINDS WILL BE NORTH
WITH GUSTS TO NEAR 30 KNOTS THROUGH 02Z AT THE KSOA AND KBBD
TERMINALS.
21
PREV DISCUSSION... /ISSUED 322 PM CDT FRI MAY 10 2013/
SHORT TERM...
BAND OF STRONG TO SEVERE THUNDERSTORMS IN THE CONCHO VALLEY
SOUTHWEST INTO CROCKETT COUNTY...ASSOCIATED WITH A COLD
FRONT...WAS STEADILY MOVING SOUTHEAST THIS AFTERNOON. A SEVERE
THUNDERSTORMS WATCH IS IN EFFECT FOR MUCH OF WEST CENTRAL
TEXAS...SOUTH OF THE BIG COUNTRY UNTIL 10 PM CDT TONIGHT. ATMOSPHERE
WAS UNSTABLE THIS AFTERNOON AS COLDER AIR ALOFT...ASSOCIATED WITH
AN UPPER LEVEL TROUGH OVER NEW MEXICO MOVED EAST. SPC RAP SB CAPES
WERE 1500-2500 J/KG. THIS IS LOWER THAN YESTERDAY...BUT STILL
ENOUGH TO GET GOLFBALL SIZE HAIL IN COKE COUNTY FROM A SUPERCELL
THIS AFTERNOON.
SEVERE STORM ACTIVITY SHOULD NOT BE QUITE AS EXTENSIVE AS
YESTERDAY...AND SHOULD WEAKEN BY SUNSET WITH LOSS OF DAYTIME
HEATING AND PASSAGE OF THE COLD FRONT.
STILL KEEPING A CHANCE OF SHOWERS AND THUNDERSTORMS SATURDAY AS
THE UPPER TROUGH MOVES ACROSS THE REGION. DRIER AIR WILL ALSO MOVE
IN FROM NORTH TO SOUTH...SO SEVERE THUNDERSTORMS ARE NOT EXPECTED.
MOST STORMS SHOULD BE ALONG THE I-10 CORRIDOR AND END BY LATE
AFTERNOON.
04
LONG TERM...
SHOWER AND THUNDERSTORM CHANCES RETURN TUESDAY AS A CUT OFF UPPER
LOW OVER BAJA CALIFORNIA MOVES NORTHEAST AND WEAKENS OVER NEW
MEXICO AND THE TEXAS PANHANDLE. MOVEMENT AND PLACEMENT OF CUT OFF
UPPER LOWS HAS ALWAYS BEEN DIFFICULT...ESPECIALLY WHEN THEY KICK
OUT. WILL KEEP POPS FAIRLY LOW AT THIS TIME...IN THE 20 TO 30
PERCENT RANGE...WITH THE HIGHER POPS ALONG THE I-10 CORRIDOR.
THUS IT POSSIBLE THAT THE SYSTEM BEGIN TO MOVE SLOWER THAN
FORECAST...DESPITE FAIRLY GOOD AGREEMENT IN RUN CONTINUITY AND
BETWEEN THE GFS AND EC MODELS. REMOVED POPS BY THURSDAY AS THE
UPPER DISTURBANCE MOVES NE AND AN UPPER RIDGE BUILDS IN.
04
&&
.PRELIMINARY POINT TEMPS/POPS...
ABILENE 56 80 54 79 58 / 20 10 10 5 5
SAN ANGELO 58 79 54 81 55 / 20 20 10 10 5
JUNCTION 58 77 53 81 53 / 20 20 10 10 5
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
757 PM CDT FRI MAY 10 2013
.UPDATE...
RAISED RAIN CHANCES OVER THE WESTERN COUNTIES GENERALLY WEST OF A
LINE FROM MADISONVILLE TO HEMPSTEAD TO EDNA. A SURFACE BOUNDARY
WAS EVIDENT ON THE KGRK RADAR AND THUNDERSTORMS WERE DEVELOPING
ALONG THE LINE JUST WEST OF BURLESON AND WASHINGTON COUNTIES. THE
00Z SOUNDINGS SHOW THE BEST INSTABILITY IS LIKELY OVER THE WESTERN
AND SOUTHWESTERN SET OF COUNTIES...LIKELY ALONG AND SOUTH OF THE
SURFACE BOUNDARY. EARLY EVENING UPDATE GOING OUT AND WILL REASSESS
THE SITUATION AT LEAST ONCE MORE BETWEEN NOW AND 10 PM.
40
&&
.PREV DISCUSSION... /ISSUED 634 PM CDT FRI MAY 10 2013/
DISCUSSION...
00Z TAF DISCUSSION IN AVIATION SECTION.
AVIATION...
TOUGH SITUATION WITH ONGOING CONVECTION MOVING INTO C TX THIS
EVENING. NONE OF THE MESOSCALE MODELS REALLY HAVE A GOOD HANDLE ON
THE CURRENT ACTIVITY BUT THE HRRR AND LATEST WRF-ARW SEEM TO HAVE
DECENT TRENDS. WRF IS MUCH FASTER WITH THE CONVECTION BUT MAY HAVE
THE RIGHT AREAS. HRRR SEEMS TO HAVE BETTER TIMING BUT WEAKER. FOR
NOW TAFS WILL HAVE PREVAILING -SHRA/SHRA AFTER 04/05Z. COULD SEE
AN UPGRADE TO TS DEPENDING ON THE EVOLUTION OF THIS SYSTEM AND
WITH THE APPROACH OF A COLD FRONT. COLD FRONT CURRENTLY RUNS FROM
THE ARKLATEX INTO NW HILL COUNTRY. SHORT WAVE KICKING OFF CURRENT
ROUND OF CONVECTION IN C TX SHOULD ALSO MOVE INTO THE AREA AROUND
MIDNIGHT. ALL POINTS TO POSSIBILITY OF ORGANIZED CONVECTION BUT
UNCERTAIN AS TO WHERE IT WILL MAKE MOST IMPACT FOR SE TX
TERMINALS. MAY GET SOME IFR CIGS AS BOUNDARY LAYER COOLS WITH
HIGHER LOW LEVEL MOISTURE. MAY AT LEAST GET MIX OF SHOWERS AND
RESTRICTED VSBY AHEAD AND ALONG THE FRONT. EXPECT CIGS TO LIFT
LATE TOMORROW MORNING WITH FRONT PASSING.
39
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 62 81 58 82 58 / 60 40 10 10 10
HOUSTON (IAH) 64 80 63 83 60 / 60 50 10 10 10
GALVESTON (GLS) 69 78 69 80 67 / 60 60 20 10 10
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...FLASH FLOOD WATCH UNTIL 7 AM CDT SATURDAY FOR THE FOLLOWING
ZONES: FORT BEND...GRIMES...HARRIS...LIBERTY...MONTGOMERY...
POLK...SAN JACINTO...WALKER...WALLER.
GM...NONE.
&&
$$
DISCUSSION...40
AVIATION/MARINE...39
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
718 PM CDT FRI MAY 10 2013
.UPDATE...
SEE UPDATE DISCUSSION BELOW.
&&
.DISCUSSION...
UPDATED ZONES AND HAZARD GRID TO CANCEL SEVERE THUNDERSTORM WATCH
#156. ALSO...UPDATED HOURLY TEMPS DUE TO CURRENT READINGS IN THE
60S ACROSS MUCH OF THE AREA.
21
&&
.PREV DISCUSSION... /ISSUED 617 PM CDT FRI MAY 10 2013/
DISCUSSION...
SEE 00Z AVIATION DISCUSSION BELOW.
AVIATION...
SCATTERED TSTMS CURRENTLY OVER THE HEARTLAND AND NORTHWEST HILL
COUNTRY WILL EXIT THE AREA BY 01Z. ISOLD TSTMS WILL STILL BE
POSSIBLE THIS EVENING MAINLY SOUTH OF THE I-20 CORRIDOR. HAVE A
VCTS GOING AT THE KJCT AND KBBD TERMINALS THROUGH 02Z. OTHERWISE
MAINLY VFR CONDITIONS ARE EXPECTED THE NEXT 24 HOURS...WITH
ABUNDANT HIGH CLOUDS OVER WEST CENTRAL TEXAS. WINDS WILL BE NORTH
WITH GUSTS TO NEAR 30 KNOTS THROUGH 02Z AT THE KSOA AND KBBD
TERMINALS.
21
PREV DISCUSSION... /ISSUED 322 PM CDT FRI MAY 10 2013/
SHORT TERM...
BAND OF STRONG TO SEVERE THUNDERSTORMS IN THE CONCHO VALLEY
SOUTHWEST INTO CROCKETT COUNTY...ASSOCIATED WITH A COLD
FRONT...WAS STEADILY MOVING SOUTHEAST THIS AFTERNOON. A SEVERE
THUNDERSTORMS WATCH IS IN EFFECT FOR MUCH OF WEST CENTRAL
TEXAS...SOUTH OF THE BIG COUNTRY UNTIL 10 PM CDT TONIGHT. ATMOSPHERE
WAS UNSTABLE THIS AFTERNOON AS COLDER AIR ALOFT...ASSOCIATED WITH
AN UPPER LEVEL TROUGH OVER NEW MEXICO MOVED EAST. SPC RAP SB CAPES
WERE 1500-2500 J/KG. THIS IS LOWER THAN YESTERDAY...BUT STILL
ENOUGH TO GET GOLFBALL SIZE HAIL IN COKE COUNTY FROM A SUPERCELL
THIS AFTERNOON.
SEVERE STORM ACTIVITY SHOULD NOT BE QUITE AS EXTENSIVE AS
YESTERDAY...AND SHOULD WEAKEN BY SUNSET WITH LOSS OF DAYTIME
HEATING AND PASSAGE OF THE COLD FRONT.
STILL KEEPING A CHANCE OF SHOWERS AND THUNDERSTORMS SATURDAY AS
THE UPPER TROUGH MOVES ACROSS THE REGION. DRIER AIR WILL ALSO MOVE
IN FROM NORTH TO SOUTH...SO SEVERE THUNDERSTORMS ARE NOT EXPECTED.
MOST STORMS SHOULD BE ALONG THE I-10 CORRIDOR AND END BY LATE
AFTERNOON.
04
LONG TERM...
SHOWER AND THUNDERSTORM CHANCES RETURN TUESDAY AS A CUT OFF UPPER
LOW OVER BAJA CALIFORNIA MOVES NORTHEAST AND WEAKENS OVER NEW
MEXICO AND THE TEXAS PANHANDLE. MOVEMENT AND PLACEMENT OF CUT OFF
UPPER LOWS HAS ALWAYS BEEN DIFFICULT...ESPECIALLY WHEN THEY KICK
OUT. WILL KEEP POPS FAIRLY LOW AT THIS TIME...IN THE 20 TO 30
PERCENT RANGE...WITH THE HIGHER POPS ALONG THE I-10 CORRIDOR.
THUS IT POSSIBLE THAT THE SYSTEM BEGIN TO MOVE SLOWER THAN
FORECAST...DESPITE FAIRLY GOOD AGREEMENT IN RUN CONTINUITY AND
BETWEEN THE GFS AND EC MODELS. REMOVED POPS BY THURSDAY AS THE
UPPER DISTURBANCE MOVES NE AND AN UPPER RIDGE BUILDS IN.
04
&&
.PRELIMINARY POINT TEMPS/POPS...
ABILENE 56 80 54 79 58 / 20 10 10 5 5
SAN ANGELO 58 79 54 81 55 / 30 20 10 10 5
JUNCTION 58 77 53 81 53 / 30 20 10 10 5
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
634 PM CDT FRI MAY 10 2013
.DISCUSSION...
00Z TAF DISCUSSION IN AVIATION SECTION.
&&
.AVIATION...
TOUGH SITUATION WITH ONGOING CONVECTION MOVING INTO C TX THIS
EVENING. NONE OF THE MESOSCALE MODELS REALLY HAVE A GOOD HANDLE ON
THE CURRENT ACTIVITY BUT THE HRRR AND LATEST WRF-ARW SEEM TO HAVE
DECENT TRENDS. WRF IS MUCH FASTER WITH THE CONVECTION BUT MAY HAVE
THE RIGHT AREAS. HRRR SEEMS TO HAVE BETTER TIMING BUT WEAKER. FOR
NOW TAFS WILL HAVE PREVAILING -SHRA/SHRA AFTER 04/05Z. COULD SEE
AN UPGRADE TO TS DEPENDING ON THE EVOLUTION OF THIS SYSTEM AND
WITH THE APPROACH OF A COLD FRONT. COLD FRONT CURRENTLY RUNS FROM
THE ARKLATEX INTO NW HILL COUNTRY. SHORT WAVE KICKING OFF CURRENT
ROUND OF CONVECTION IN C TX SHOULD ALSO MOVE INTO THE AREA AROUND
MIDNIGHT. ALL POINTS TO POSSIBILITY OF ORGANIZED CONVECTION BUT
UNCERTAIN AS TO WHERE IT WILL MAKE MOST IMPACT FOR SE TX
TERMINALS. MAY GET SOME IFR CIGS AS BOUNDARY LAYER COOLS WITH
HIGHER LOW LEVEL MOISTURE. MAY AT LEAST GET MIX OF SHOWERS AND
RESTRICTED VSBY AHEAD AND ALONG THE FRONT. EXPECT CIGS TO LIFT
LATE TOMORROW MORNING WITH FRONT PASSING.
39
&&
.PREV DISCUSSION... /ISSUED 506 PM CDT FRI MAY 10 2013/
DISCUSSION...
EXTENDED THE FLASH FLOOD WATCH THROUGH 7 AM SATURDAY DUE TO THE
CONVECTION IN CENTRAL TEXAS MOVING EASTWARD. WILL REASSESS AROUND
MID EVENING.
40
PREV DISCUSSION... /ISSUED 350 PM CDT FRI MAY 10 2013/
DISCUSSION...
CLEARING SKIES IN THE WAKE OF THE MCS THAT MOVED THROUGH THIS
MORNING HAVE ALLOWED FOR ENOUGH INSTABILITY TO SUPPORT SCATTERED
SHOWERS AND THUNDERSTORMS ACROSS THE REGION THIS AFTERNOON. THIS
ACTIVITY WILL CONTINUE THROUGH THE AFTERNOON HOURS BUT MOST OF THE
REGION LOOKS TO REMAIN DRY THROUGH THE EARLY EVENING.
OUR NEXT CHANCE FOR WIDESPREAD SHOWERS AND THUNDERSTORMS IS
BEGINNING TO TAKE SHAPE ACROSS WEST TEXAS AS YET ANOTHER
APPROACHING SHORTWAVE IS AIDING IN THE DEVELOPMENT OF SOME STRONG
TO SEVERE THUNDERSTORMS ACROSS THE TRANS PECOS REGION. A SEVERE
THUNDERSTORM WATCH IS IN EFFECT ACROSS THAT REGION THROUGH LATE
EVENING AND MAY BE EXTENDED FURTHER EASTWARD IF STORMS CAN
MAINTAIN THEIR INTENSITY. MESOSCALE MODELS HAVE DONE A POOR JOB IN
REALIZING THUNDERSTORM ACTIVITY OVER THE PAST FEW DAYS BUT LATEST
HRRR MODEL RUNS APPEAR TO SHOW A PLAUSIBLE SCENARIO FOR TONIGHT
WITH AN AREA OF SHOWERS AND THUNDERSTORMS MOVING THROUGH THE
REGION AFTER MIDNIGHT AND INTO THE MORNING HOURS. LOWER LEVELS OF
THE ATMOSPHERE ARE STILL SOMEWHAT WORKED OVER AFTER THE ACTIVITY
THIS MORNING SO AM NOT AS CONCERNED WITH THE THREAT FOR SEVERE
WEATHER ALTHOUGH MINOR FLOODING WILL STILL REMAIN A LINGERING
CONCERN GIVEN THE COPIOUS AMOUNT OF RAIN WE HAVE ALREADY SEEN IN
THE LAST 24 HOURS. DAYTIME ACTIVITY TOMORROW APPEARS TO SHIFT
SOUTH OF INTERSTATE 10 AND INTO THE COASTAL COUNTIES AS THE
SURFACE BOUNDARY MOVES THROUGH THE REGION.
EXTENDED FORECAST LOOKS MOSTLY DRY BEGINNING ON SUNDAY AND
CONTINUING INTO TUESDAY AS WEAK RIDGING DEVELOPS ACROSS THE STATE.
SLIGHT RAIN CHANCES EXPECTED FOR MID WEEK AS THE UPPER LEVEL LOW
OFF TO OUR WEST FINALLY OPENS UP INTO A WAVE AND MOVES ACROSS
NORTH TEXAS. EXPECT TEMPERATURES IN THE LOW TO MID 80S WITH LIGHT
ONSHORE WINDS THROUGH MUCH OF NEXT WEEK. 38
MARINE...
MESOHIGH/WAKE LOW MOVING AWAY AND EASTERLY WINDS RELAXING. SCA TIL 4
PM AND WILL BE ALLOWED TO EXPIRE. EASTERLY FLOW WILL BECOME
NORTHEAST OVERNIGHT AND SATURDAY AS COLD FRONT FINALLY MOVES OFF THE
COAST BETWEEN 8 AM AND NOON. SHOWERS AND THUNDERSTORMS THREAT WILL
CONTINUE THROUGH SATURDAY THEN LESSEN AS THE AREA DRIES OUT.
45
AVIATION...
VFR CIGS AT MOST SITES WITH EASTERLY FLOW RELAXING. T/TD SPREADS
MUCH LESS THAN YESTERDAY AND WITH THE CLEARING SKIES/WET GROUND
EXPECT A GOOD SETUP FOR FOG. AFTER 06Z EXPECTING MVFR CIGS AND FOG
AND MAY LOWER INTO IFR. S/W SHOULD BRING IN MORE SHOWERS AFTER 09Z
AND THROUGH 15Z SATURDAY SHIFTING TOWARD THE COAST AND THEN OUT INTO
THE GULF WITH THE FRONTAL PASSAGE.
45
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 62 81 58 82 58 / 50 40 10 10 10
HOUSTON (IAH) 64 80 63 83 60 / 60 50 10 10 10
GALVESTON (GLS) 69 78 69 80 67 / 60 60 20 10 10
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...FLASH FLOOD WATCH THROUGH SATURDAY MORNING FOR THE FOLLOWING
ZONES: FORT BEND...GRIMES...HARRIS...LIBERTY...MONTGOMERY...
POLK...SAN JACINTO...WALKER...WALLER.
GM...NONE.
&&
$$
DISCUSSION...40
AVIATION/MARINE...39
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
617 PM CDT FRI MAY 10 2013
.DISCUSSION...
SEE 00Z AVIATION DISCUSSION BELOW.
&&
.AVIATION...
SCATTERED TSTMS CURRENTLY OVER THE HEARTLAND AND NORTHWEST HILL
COUNTRY WILL EXIT THE AREA BY 01Z. ISOLD TSTMS WILL STILL BE
POSSIBLE THIS EVENING MAINLY SOUTH OF THE I-20 CORRIDOR. HAVE A
VCTS GOING AT THE KJCT AND KBBD TERMINALS THROUGH 02Z. OTHERWISE
MAINLY VFR CONDITIONS ARE EXPECTED THE NEXT 24 HOURS...WITH
ABUNDANT HIGH CLOUDS OVER WEST CENTRAL TEXAS. WINDS WILL BE NORTH
WITH GUSTS TO NEAR 30 KNOTS THROUGH 02Z AT THE KSOA AND KBBD
TERMINALS.
21
&&
.PREV DISCUSSION... /ISSUED 322 PM CDT FRI MAY 10 2013/
SHORT TERM...
BAND OF STRONG TO SEVERE THUNDERSTORMS IN THE CONCHO VALLEY
SOUTHWEST INTO CROCKETT COUNTY...ASSOCIATED WITH A COLD
FRONT...WAS STEADILY MOVING SOUTHEAST THIS AFTERNOON. A SEVERE
THUNDERSTORMS WATCH IS IN EFFECT FOR MUCH OF WEST CENTRAL
TEXAS...SOUTH OF THE BIG COUNTRY UNTIL 10 PM CDT TONIGHT. ATMOSPHERE
WAS UNSTABLE THIS AFTERNOON AS COLDER AIR ALOFT...ASSOCIATED WITH
AN UPPER LEVEL TROUGH OVER NEW MEXICO MOVED EAST. SPC RAP SB CAPES
WERE 1500-2500 J/KG. THIS IS LOWER THAN YESTERDAY...BUT STILL
ENOUGH TO GET GOLFBALL SIZE HAIL IN COKE COUNTY FROM A SUPERCELL
THIS AFTERNOON.
SEVERE STORM ACTIVITY SHOULD NOT BE QUITE AS EXTENSIVE AS
YESTERDAY...AND SHOULD WEAKEN BY SUNSET WITH LOSS OF DAYTIME
HEATING AND PASSAGE OF THE COLD FRONT.
STILL KEEPING A CHANCE OF SHOWERS AND THUNDERSTORMS SATURDAY AS
THE UPPER TROUGH MOVES ACROSS THE REGION. DRIER AIR WILL ALSO MOVE
IN FROM NORTH TO SOUTH...SO SEVERE THUNDERSTORMS ARE NOT EXPECTED.
MOST STORMS SHOULD BE ALONG THE I-10 CORRIDOR AND END BY LATE
AFTERNOON.
04
LONG TERM...
SHOWER AND THUNDERSTORM CHANCES RETURN TUESDAY AS A CUT OFF UPPER
LOW OVER BAJA CALIFORNIA MOVES NORTHEAST AND WEAKENS OVER NEW
MEXICO AND THE TEXAS PANHANDLE. MOVEMENT AND PLACEMENT OF CUT OFF
UPPER LOWS HAS ALWAYS BEEN DIFFICULT...ESPECIALLY WHEN THEY KICK
OUT. WILL KEEP POPS FAIRLY LOW AT THIS TIME...IN THE 20 TO 30
PERCENT RANGE...WITH THE HIGHER POPS ALONG THE I-10 CORRIDOR.
THUS IT POSSIBLE THAT THE SYSTEM BEGIN TO MOVE SLOWER THAN
FORECAST...DESPITE FAIRLY GOOD AGREEMENT IN RUN CONTINUITY AND
BETWEEN THE GFS AND EC MODELS. REMOVED POPS BY THURSDAY AS THE
UPPER DISTURBANCE MOVES NE AND AN UPPER RIDGE BUILDS IN.
04
&&
.PRELIMINARY POINT TEMPS/POPS...
ABILENE 56 80 54 79 58 / 20 10 10 5 5
SAN ANGELO 58 79 54 81 55 / 30 20 10 10 5
JUNCTION 58 77 53 81 53 / 30 20 10 10 5
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS FORT WORTH TX
128 PM CDT THU MAY 9 2013
.AVIATION...
FOR THE 18Z TAFS...THE THUNDERSTORM FORECAST FOR AREA AIRPORTS IS
THE PRIMARY FORECAST CHALLENGE THROUGH THE VALID FORECAST PERIOD.
THE FORECAST FOR THUNDERSTORMS IN AND AROUND AREA AIRPORTS IS
COMPLICATED BY THE EXISTENCE OF MULTIPLE FORCING MECHANISMS FOR
STORM DEVELOPMENT...AND THE WIDESPREAD PRESENCE OF AVAILABLE
MOISTURE AND INSTABILITY TO SUPPORT STORMS ACROSS THE REGION. IN
GENERAL THIS FORECAST CLOSELY FOLLOWS THE MODELED SIMULATED
REFLECTIVITY ADVERTISED IN THE 12Z TEXAS TECH WRF.
FOR THE DFW AREA...EXPECT THAT WIDESPREAD RAIN SHOWERS WITH
EMBEDDED THUNDERSTORMS WILL PERSIST THROUGH 21Z. DO NOT EXPECT ANY
SIGNIFICANT CHANGE IN INTENSITY OF THIS ACTIVITY THROUGH 21Z. FOR
KACT...A SEVERE THUNDERSTORM OVER HAMILTON AND CORYELL COUNTIES
WAS MOVING DUE EAST TOWARDS THE AIRPORT AT THE TIME OF THIS
DISCUSSION. A BASIC LINEAR EXTRAPOLATION OF ITS 18Z MOVEMENT BRINGS
THE STORM OVER KACT AT 1915Z...SO THIS IS THE TIME THAT WAS USED
FOR THIS LINE OF STORMS IN THE TAF. IF THE LINE MAINTAINS ITS
INTENSITY AS IT BUILDS INTO MCLENNAN COUNTY...WILL HAVE TO AMEND
TO INCREASE WIND SPEEDS AND MENTION HAIL AT THE AIRPORT. THIS LINE
OF STORMS IS EXPECTED TO MOVE EAST OF KACT AFTER 21Z.
AS THE LINE OF STRONG TO SEVERE THUNDERSTORMS MOVES EAST OF THE
INTERSTATE 35 CORRIDOR AFTER 21Z...SUBSIDENCE IS EXPECTED TO CAUSE
A DECREASE IN THE COVERAGE AND INTENSITY OF PRECIPITATION AROUND
ALL AREA AIRPORTS. ATTENTION THEN TURNS TO THE NORTHWEST WHERE
THUNDERSTORMS WERE ALREADY DEVELOPING NEAR THE COLD FRONT/DRYLINE
INTERSECTION NEAR SNYDER TX. THE 12Z TEXAS TECH WRF INDICATES THAT
THIS ACTIVITY WILL GROW UPSCALE INTO A SQUALL LINE THAT WILL MOVE
EAST AND APPROACH DFW AREA TAF SITES BY 01Z. THIS LINE OF
STORMS...IF IT EVOLVES...IS EXPECTED TO MOVE EAST QUICKLY ONLY
REMAINING OVER THE METROPLEX FOR A COUPLE OF HRS. BEHIND THIS LINE
OF STORMS...SOME LIGHT RAIN MAY PERSIST FOR A FEW HRS AS THE LOW
LEVEL JET INTERACTS WITH THE OUTFLOW FROM THE LINE OF STORMS.
THE FRONT IS EXPECTED TO MOVE THROUGH THE DFW AREA FRIDAY
MORNING...WITH A FRONTAL PASSAGE OF AROUND 15Z AT THIS TIME. THE
FRONT IS EXPECTED TO MOVE THROUGH KACT A COUPLE OF HOURS LATER.
THE FRONT IS NOT EXPECTED TO HAVE A STRONG PUSH FROM LOW PRESSURE
ALOFT...SO THE FRONTAL TIMING WILL LIKELY DEPEND ON THUNDERSTORM
ACTIVITY ALONG AND BEHIND THE FRONT. THE MORE STORMS
OVERNIGHT...THE FASTER IT WILL TEND TO MOVE SOUTH. WHENEVER THE
FRONT MOVES THROUGH...IT IS EXPECTED TO PROVIDE ENOUGH LIFT FOR
SOME SCATTERED RAIN SHOWERS AND ISOLATED THUNDERSTORMS AT AREA TAF
SITES.
CAVANAUGH
&&
.UPDATE...
CONVECTIVE COMPLEX CONTINUES TO DEVELOP IN THE CONCHO
VALLEY...MOVING NORTHEAST INTO NORTH AND CENTRAL TEXAS. SMALL HAIL
HAS BEEN REPORTED WITH THE STRONGER STORMS IN THE CONCHO VALLEY
BUT THE STORMS CONTINUE TO REMAIN BELOW SEVERE LIMITS FOR NOW.
A COMPLICATED CONVECTIVE EVOLUTION IS EXPECTED TODAY WITH TWO OR
THREE COMPLEXES/ROUNDS OF STORMS LIKELY TO AFFECT THE REGION
THROUGH TONIGHT. ANALYZING THE LATEST HI-RES AND SHORT TERM MODEL
DATA...LATEST THINKING IS NOT TOO FAR OFF FROM THE PREVIOUS
FORECAST. THE ONGOING COMPLEX OF STORMS WILL CONTINUE TO MOVE
NORTHEAST WITH ADDITIONAL CONVECTIVE DEVELOPMENT AS WE APPROACH
THE MIDDAY AND EARLY AFTERNOON HOURS. THIS MCS WILL LARGELY AFFECT
THE SOUTH AND SOUTHWESTERN HALVES OF THE CWA. IT IS POSSIBLE THAT
AN ADDITIONAL COMPLEX OF STORMS COULD DEVELOP OFF THIS INITIAL
COMPLEX THIS AFTERNOON. SEVERE STORMS EMBEDDED WITHIN THE MCS ARE
LIKELY...BUT THE CLOUD COVER ACROSS THE REGION WILL PLAY A KEY
ROLE IN HOW WIDESPREAD THE SEVERE STORMS ARE THIS AFTERNOON. AMPLE
MOISTURE IS ALREADY IN PLACE ACROSS THE REGION WITH STEEP LAPSE
RATES ABOVE THE MORNING CAP. THIS CAP IS EXPECTED TO WEAKEN
THROUGHOUT THE DAY AND IF BREAKS IN THE CLOUDS OCCUR THIS
AFTERNOON...INSTABILITY COULD JUMP TO OVER 3000 J/KG ACROSS THE
REGION...PER THE LATEST RAP SOUNDINGS. THIS WOULD INCREASE THE
SEVERE WEATHER POTENTIAL WITH LARGE HAIL AND DAMAGING WINDS BEING
THE MAIN SEVERE WEATHER THREATS. THESE STORMS WILL GENERALLY MOVE
OFF TO THE EAST LATE THIS AFTERNOON AND EVENING.
THE OTHER FOCUS FOR STORM DEVELOPMENT THIS AFTERNOON IS ALONG THE
DRYLINE. THE DRYLINE IS CURRENTLY WELL TO OUR WEST IN FAR WEST
TEXAS BUT IS EXPECTED TO BULGE NEAR OUR NORTHWEST COUNTIES LATE
THIS AFTERNOON. MODELS CONTINUE TO DEVELOP STORMS ALONG THE
DRYLINE THIS AFTERNOON WITH A THREAT FOR SEVERE STORMS. SEVERAL OF
THE MODELS MERGE THE STORMS ALONG THE DRYLINE INTO A COMPLEX OF
STORMS THAT MOVES EAST/SOUTHEAST THIS EVENING AND TONIGHT. MAIN
SEVERE WEATHER THREATS WOULD ALSO BE LARGE HAIL AND DAMAGING WINDS
WITH THESE STORMS.
FOR THE UPDATE...ADJUSTED CLOUD COVER UP ACROSS THE REGION AND
LOWERED HIGH TEMPERATURES INTO THE LOW TO MID 70S ACROSS MOST OF
THE REGION. THE EXCEPTION WILL BE IN THE NORTHWEST WHERE
TEMPERATURES WILL LIKELY REACH THE LOWER 80S UNDER PARTLY CLOUDY
TO MOSTLY CLOUDY SKIES. ALSO INCREASED AND ADJUSTED POPS WITH THE
HIGHEST POPS STILL GENERALLY ALONG AND SOUTH OF INTERSTATE 20.
82/JLD
&&
.PREV DISCUSSION... /ISSUED 355 AM CDT THU MAY 9 2013/
MORNING WATER VAPOR IMAGERY FEATURES SEVERAL SWIRLING VORTICES
ACROSS THE CONUS ALONG WITH A COUPLE OF COMPLEXES OF THUNDERSTORMS
AND A STEADY STREAM OF HIGH LEVEL PACIFIC MOISTURE VIA THE
SUBTROPICAL JET. OF IMPORTANCE TO NORTH TEXAS WEATHER OVER THE
NEXT 36 HOURS WILL BE THE LARGE BUT RATHER WEAK UPPER LOW OVER THE
SOUTHWEST US AND ITS ASSOCIATED EMBEDDED VORTICITY MAXIMA THAT
PERIODICALLY ROTATE AROUND AND EJECT EASTWARD. TIMING OF THESE
FEATURES AND THEIR ASSOCIATED FORCING FOR ASCENT WILL MAKE FOR A
MODERATELY CHALLENGING FORECAST THROUGH FRIDAY.
00Z MODEL DATA/UPPER AIR DATA AND WATER VAPOR IMAGERY CONFIRM THE
PRESENCE A SHORTWAVE WHICH IS CURRENTLY MOVING ACROSS NORTHWEST MEXICO
THIS MORNING. THIS IS A LITTLE FASTER THAN THE GUIDANCE SUGGESTED
FROM YESTERDAY. TIMING THIS FEATURE BASED ON ITS CURRENT SPEED WOULD
SUGGEST THAT THE STRONGEST FORCING FOR ASCENT ASSOCIATED WITH IT
WOULD BEGIN TO OVERSPREAD SOUTHWEST TEXAS SHORTLY AND SPREAD INTO
NORTH TEXAS THROUGH MID MORNING. MOST OF THE HIGH RESOLUTION
GUIDANCE QUICKLY DEVELOPS SCATTERED SHOWERS AND THUNDERSTORMS
THROUGH LATE MORNING ACROSS THE EDWARDS PLATEAU AND SPREADS THEM
EAST-NORTHEAST INTO OUR CWA. THERE IS EVEN A STRONG SIGNAL WITHIN
THE LOWER RES GLOBAL GUIDANCE WHICH SUPPORTS THIS SCENARIO.
OBVIOUSLY WITH A MUCH EARLIER START TO CONVECTIVE ACTIVITY...THE
OVERALL SEVERE WEATHER THREAT WOULD BE LOWER...HOWEVER...DEEP
LAYER WIND FIELDS ARE QUITE A BIT STRONGER THIS MORNING THAN THEY
WILL BE BY THIS EVENING. FORECAST SOUNDINGS ACROSS THE CWA SHOW
THE CONTINUED PRESENCE OF STEEP MID LEVEL LAPSE RATES...AND WITH
AMPLE EFFECTIVE DEEP LAYER SHEAR...WOULD NOT RULE OUT INITIAL
ELEVATED SUPERCELL DEVELOPMENT THROUGH LATE MORNING. LARGE HAIL
WOULD BE THE PRIMARY THREAT DURING THIS TIME. THUNDERSTORMS THAT
DEVELOP THROUGH THE MORNING WOULD LIKELY TEND TO CLUSTER INTO AN
MCS AND SPREAD EAST OR SOUTHEASTWARD. UNFORTUNATELY THERE IS LARGE
SPREAD WITHIN THE GUIDANCE AS TO HOW FAR NORTH ANY SUCH COMPLEX OF
STORMS WOULD SPREAD...BUT CURRENT THINKING IS THAT BEST CHANCES
THROUGH THIS AFTERNOON WILL GENERALLY BE SOUTH OF INTERSTATE 20.
WILL HAVE HIGHEST POPS ACROSS THE SOUTHWEST COUNTIES THIS MORNING
AND SPREAD THEM ACROSS THE SOUTHERN AND SOUTHEAST THROUGH THIS EVENING.
ANOTHER AREA OF CONCERN FOR CONVECTIVE DEVELOPMENT WILL BE ALONG
THE FRONT/DRYLINE INTERSECTION ACROSS NORTHWEST TEXAS LATE THIS
AFTERNOON AND EVENING. THIS AREA APPEARS TO BE A LITTLE MORE
QUESTIONABLE AS MORNING/EARLY AFTERNOON CONVECTION WOULD LIKELY
INHIBIT ADDITIONAL DEVELOPMENT. WITH BEST FORCING FOR ASCENT
SPREADING ACROSS NORTH TEXAS DURING THE FIRST HALF OF THE
DAY...WEAK SUBSIDENCE WOULD LIKELY FOLLOW IN ITS WAKE...ESPECIALLY
IF AN ORGANIZED COMPLEX OF STORMS DEVELOPS FARTHER SOUTH. THAT
BEING SAID...FORECAST SOUNDINGS FOR LATE THIS AFTERNOON ACROSS
NORTHWEST TEXAS SHOW ONLY A WEAKLY CAPPED UNSTABLE PROFILE. THIS
WEAK CAPPING MAY BE THE MODELS FAILURE TO CAPTURE MORE ROBUST
SUBSIDENCE IN THE WAKE OF EARLIER CONVECTION. EITHER WAY...THE
HIGH RESOLUTION GUIDANCE VARIES ON THE DEVELOPMENT OF
THUNDERSTORMS THROUGH EARLY EVENING ACROSS NORTHWEST TEXAS
DEPENDING ON WHAT HAPPENS FARTHER SOUTH. GIVEN THAT THERE WILL BE
A FAIRLY LARGE UNPERTURBED AREA OF MODERATELY STRONG INSTABILITY
AND AT LEAST SOME FOCUSED LOW LEVEL FORCING ALONG THE
FRONT/DRYLINE AND POSSIBLY RESIDUAL OUTFLOW BOUNDARIES FROM EARLY
MORNING CONVECTION ACROSS OKLAHOMA...THINK AT LEAST ISOLATED SURFACE
BASED THUNDERSTORMS WILL DEVELOP BY THIS EVENING ACROSS PARTS OF
NORTHWEST TEXAS. A LOCALLY HIGHER SEVERE WEATHER THREAT WOULD
EXIST ACROSS OUR NORTHWEST COUNTIES WITH LARGE HAIL BEING THE MAIN
THREAT IF THESE STORMS DO DEVELOP.
AS THE COLD FRONT SAGS SOUTH LATER TONIGHT...RAIN AND THUNDERSTORM
CHANCES WILL PROGRESSIVELY SHIFT FARTHER SOUTH INTO CENTRAL TEXAS.
THE FRONT WILL LIKELY GET HUNG UP ACROSS THE HILL COUNTRY BY EARLY
FRIDAY MORNING. SCATTERED THUNDERSTORMS ARE AGAIN EXPECTED ALONG
THE FRONT WITH BEST CHANCES BEING ACROSS THE SOUTHERN COUNTIES.
WITH STEEP LAPSE RATES STILL IN PLACE ACROSS THIS AREA...SEVERE
HAIL WILL REMAIN A THREAT WITH THIS ACTIVITY. ACTIVITY TOMORROW
AFTERNOON SHOULD AGAIN DEVELOP INTO AN MCS AND HEAD SOUTHEAST OUT
OF THE AREA. FRONTAL BOUNDARY WOULD GET PUSHED FARTHER SOUTH BY
SATURDAY WITH POPS TAPERING BACK DOWN TO JUST 20 PERCENT ACROSS
THE SOUTHERN COUNTIES.
WITH THE MAIN UPPER LOW DRIFTING ACROSS NORTHWEST MEXICO OVER THE
WEEKEND...THERE SHOULD BE A FEW QUIET DAYS TO START NEXT WEEK. THE
UPPER LOW FINALLY GETS KICKED OUT BY MIDWEEK WITH ANOTHER SHOT OF
SHOWERS AND THUNDERSTORMS BY WEDNESDAY.
DUNN
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 76 66 79 59 77 / 90 60 20 20 10
WACO, TX 75 64 80 61 78 / 80 60 30 30 20
PARIS, TX 75 61 79 56 76 / 40 60 20 20 10
DENTON, TX 76 62 78 57 77 / 50 60 20 20 10
MCKINNEY, TX 75 62 78 57 78 / 60 60 20 20 10
DALLAS, TX 76 67 81 61 79 / 90 60 20 20 10
TERRELL, TX 77 63 80 58 78 / 70 60 20 20 10
CORSICANA, TX 75 65 80 61 77 / 80 60 30 30 20
TEMPLE, TX 75 64 80 60 76 / 80 60 50 30 20
MINERAL WELLS, TX 77 61 78 57 80 / 60 50 20 20 10
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
/
AREA FORECAST DISCUSSION...UPDATED
NWS FORT WORTH TX
1042 AM CDT THU MAY 9 2013
.UPDATE...
CONVECTIVE COMPLEX CONTINUES TO DEVELOP IN THE CONCHO
VALLEY...MOVING NORTHEAST INTO NORTH AND CENTRAL TEXAS. SMALL HAIL
HAS BEEN REPORTED WITH THE STRONGER STORMS IN THE CONCHO VALLEY
BUT THE STORMS CONTINUE TO REMAIN BELOW SEVERE LIMITS FOR NOW.
A COMPLICATED CONVECTIVE EVOLUTION IS EXPECTED TODAY WITH TWO OR
THREE COMPLEXES/ROUNDS OF STORMS LIKELY TO AFFECT THE REGION
THROUGH TONIGHT. ANALYZING THE LATEST HI-RES AND SHORT TERM MODEL
DATA...LATEST THINKING IS NOT TOO FAR OFF FROM THE PREVIOUS
FORECAST. THE ONGOING COMPLEX OF STORMS WILL CONTINUE TO MOVE
NORTHEAST WITH ADDITIONAL CONVECTIVE DEVELOPMENT AS WE APPROACH
THE MIDDAY AND EARLY AFTERNOON HOURS. THIS MCS WILL LARGELY AFFECT
THE SOUTH AND SOUTHWESTERN HALVES OF THE CWA. IT IS POSSIBLE THAT
AN ADDITIONAL COMPLEX OF STORMS COULD DEVELOP OFF THIS INITIAL
COMPLEX THIS AFTERNOON. SEVERE STORMS EMBEDDED WITHIN THE MCS ARE
LIKELY...BUT THE CLOUD COVER ACROSS THE REGION WILL PLAY A KEY
ROLE IN HOW WIDESPREAD THE SEVERE STORMS ARE THIS AFTERNOON. AMPLE
MOISTURE IS ALREADY IN PLACE ACROSS THE REGION WITH STEEP LAPSE
RATES ABOVE THE MORNING CAP. THIS CAP IS EXPECTED TO WEAKEN
THROUGHOUT THE DAY AND IF BREAKS IN THE CLOUDS OCCUR THIS
AFTERNOON...INSTABILITY COULD JUMP TO OVER 3000 J/KG ACROSS THE
REGION...PER THE LATEST RAP SOUNDINGS. THIS WOULD INCREASE THE
SEVERE WEATHER POTENTIAL WITH LARGE HAIL AND DAMAGING WINDS BEING
THE MAIN SEVERE WEATHER THREATS. THESE STORMS WILL GENERALLY MOVE
OFF TO THE EAST LATE THIS AFTERNOON AND EVENING.
THE OTHER FOCUS FOR STORM DEVELOPMENT THIS AFTERNOON IS ALONG THE
DRYLINE. THE DRYLINE IS CURRENTLY WELL TO OUR WEST IN FAR WEST
TEXAS BUT IS EXPECTED TO BULGE NEAR OUR NORTHWEST COUNTIES LATE
THIS AFTERNOON. MODELS CONTINUE TO DEVELOP STORMS ALONG THE
DRYLINE THIS AFTERNOON WITH A THREAT FOR SEVERE STORMS. SEVERAL OF
THE MODELS MERGE THE STORMS ALONG THE DRYLINE INTO A COMPLEX OF
STORMS THAT MOVES EAST/SOUTHEAST THIS EVENING AND TONIGHT. MAIN
SEVERE WEATHER THREATS WOULD ALSO BE LARGE HAIL AND DAMAGING WINDS
WITH THESE STORMS.
FOR THE UPDATE...ADJUSTED CLOUD COVER UP ACROSS THE REGION AND
LOWERED HIGH TEMPERATURES INTO THE LOW TO MID 70S ACROSS MOST OF
THE REGION. THE EXCEPTION WILL BE IN THE NORTHWEST WHERE
TEMPERATURES WILL LIKELY REACH THE LOWER 80S UNDER PARTLY CLOUDY
TO MOSTLY CLOUDY SKIES. ALSO INCREASED AND ADJUSTED POPS WITH THE
HIGHEST POPS STILL GENERALLY ALONG AND SOUTH OF INTERSTATE 20.
82/JLD
&&
.AVIATION...
THUNDERSTORMS ARE FIRING UP BETWEEN KSJT /SAN ANGELO/ AND KCOM
/COLEMAN/ AS A SHORTWAVE MOVES INTO WEST TEXAS. THESE STORMS WILL
MOVE EAST NORTHEAST AND INCREASE IN AREAL COVERAGE THIS MORNING.
CURRENT FORECAST TIMING BRINGS THE STORMS INTO THE I-35 AREA
15-17Z. LARGE HAIL AND DAMAGING WINDS WILL BE POSSIBLE WITH THESE
STORMS. IF THE COMPLEX MOVES THROUGH AS FORECAST...THE
THUNDERSTORM CHANCES SHOULD BE OVER 19-21Z AS THE AIRMASS SHOULD
STABILIZE FOR THE REST OF THE AFTERNOON BEHIND THE STORM COMPLEX.
THERE WILL BE ANOTHER CHANCE OF THUNDERSTORMS OVERNIGHT AS A COLD
FRONT MOVES INTO NORTH TEXAS. SOUTHERLY WINDS WILL PREVAIL
THROUGH TONIGHT AND AS THE COLD FRONT MOVES INTO THE METROPLEX
TAF SITES AFTER 12Z FRIDAY...WINDS WILL SHIFT TO THE NORTH OR
NORTHEAST AT 10 KNOTS OR LESS.
58
&&
.PREV DISCUSSION... /ISSUED 355 AM CDT THU MAY 9 2013/
MORNING WATER VAPOR IMAGERY FEATURES SEVERAL SWIRLING VORTICES
ACROSS THE CONUS ALONG WITH A COUPLE OF COMPLEXES OF THUNDERSTORMS
AND A STEADY STREAM OF HIGH LEVEL PACIFIC MOISTURE VIA THE
SUBTROPICAL JET. OF IMPORTANCE TO NORTH TEXAS WEATHER OVER THE
NEXT 36 HOURS WILL BE THE LARGE BUT RATHER WEAK UPPER LOW OVER THE
SOUTHWEST US AND ITS ASSOCIATED EMBEDDED VORTICITY MAXIMA THAT
PERIODICALLY ROTATE AROUND AND EJECT EASTWARD. TIMING OF THESE
FEATURES AND THEIR ASSOCIATED FORCING FOR ASCENT WILL MAKE FOR A
MODERATELY CHALLENGING FORECAST THROUGH FRIDAY.
00Z MODEL DATA/UPPER AIR DATA AND WATER VAPOR IMAGERY CONFIRM THE
PRESENCE A SHORTWAVE WHICH IS CURRENTLY MOVING ACROSS NORTHWEST MEXICO
THIS MORNING. THIS IS A LITTLE FASTER THAN THE GUIDANCE SUGGESTED
FROM YESTERDAY. TIMING THIS FEATURE BASED ON ITS CURRENT SPEED WOULD
SUGGEST THAT THE STRONGEST FORCING FOR ASCENT ASSOCIATED WITH IT
WOULD BEGIN TO OVERSPREAD SOUTHWEST TEXAS SHORTLY AND SPREAD INTO
NORTH TEXAS THROUGH MID MORNING. MOST OF THE HIGH RESOLUTION
GUIDANCE QUICKLY DEVELOPS SCATTERED SHOWERS AND THUNDERSTORMS
THROUGH LATE MORNING ACROSS THE EDWARDS PLATEAU AND SPREADS THEM
EAST-NORTHEAST INTO OUR CWA. THERE IS EVEN A STRONG SIGNAL WITHIN
THE LOWER RES GLOBAL GUIDANCE WHICH SUPPORTS THIS SCENARIO.
OBVIOUSLY WITH A MUCH EARLIER START TO CONVECTIVE ACTIVITY...THE
OVERALL SEVERE WEATHER THREAT WOULD BE LOWER...HOWEVER...DEEP
LAYER WIND FIELDS ARE QUITE A BIT STRONGER THIS MORNING THAN THEY
WILL BE BY THIS EVENING. FORECAST SOUNDINGS ACROSS THE CWA SHOW
THE CONTINUED PRESENCE OF STEEP MID LEVEL LAPSE RATES...AND WITH
AMPLE EFFECTIVE DEEP LAYER SHEAR...WOULD NOT RULE OUT INITIAL
ELEVATED SUPERCELL DEVELOPMENT THROUGH LATE MORNING. LARGE HAIL
WOULD BE THE PRIMARY THREAT DURING THIS TIME. THUNDERSTORMS THAT
DEVELOP THROUGH THE MORNING WOULD LIKELY TEND TO CLUSTER INTO AN
MCS AND SPREAD EAST OR SOUTHEASTWARD. UNFORTUNATELY THERE IS LARGE
SPREAD WITHIN THE GUIDANCE AS TO HOW FAR NORTH ANY SUCH COMPLEX OF
STORMS WOULD SPREAD...BUT CURRENT THINKING IS THAT BEST CHANCES
THROUGH THIS AFTERNOON WILL GENERALLY BE SOUTH OF INTERSTATE 20.
WILL HAVE HIGHEST POPS ACROSS THE SOUTHWEST COUNTIES THIS MORNING
AND SPREAD THEM ACROSS THE SOUTHERN AND SOUTHEAST THROUGH THIS EVENING.
ANOTHER AREA OF CONCERN FOR CONVECTIVE DEVELOPMENT WILL BE ALONG
THE FRONT/DRYLINE INTERSECTION ACROSS NORTHWEST TEXAS LATE THIS
AFTERNOON AND EVENING. THIS AREA APPEARS TO BE A LITTLE MORE
QUESTIONABLE AS MORNING/EARLY AFTERNOON CONVECTION WOULD LIKELY
INHIBIT ADDITIONAL DEVELOPMENT. WITH BEST FORCING FOR ASCENT
SPREADING ACROSS NORTH TEXAS DURING THE FIRST HALF OF THE
DAY...WEAK SUBSIDENCE WOULD LIKELY FOLLOW IN ITS WAKE...ESPECIALLY
IF AN ORGANIZED COMPLEX OF STORMS DEVELOPS FARTHER SOUTH. THAT
BEING SAID...FORECAST SOUNDINGS FOR LATE THIS AFTERNOON ACROSS
NORTHWEST TEXAS SHOW ONLY A WEAKLY CAPPED UNSTABLE PROFILE. THIS
WEAK CAPPING MAY BE THE MODELS FAILURE TO CAPTURE MORE ROBUST
SUBSIDENCE IN THE WAKE OF EARLIER CONVECTION. EITHER WAY...THE
HIGH RESOLUTION GUIDANCE VARIES ON THE DEVELOPMENT OF
THUNDERSTORMS THROUGH EARLY EVENING ACROSS NORTHWEST TEXAS
DEPENDING ON WHAT HAPPENS FARTHER SOUTH. GIVEN THAT THERE WILL BE
A FAIRLY LARGE UNPERTURBED AREA OF MODERATELY STRONG INSTABILITY
AND AT LEAST SOME FOCUSED LOW LEVEL FORCING ALONG THE
FRONT/DRYLINE AND POSSIBLY RESIDUAL OUTFLOW BOUNDARIES FROM EARLY
MORNING CONVECTION ACROSS OKLAHOMA...THINK AT LEAST ISOLATED SURFACE
BASED THUNDERSTORMS WILL DEVELOP BY THIS EVENING ACROSS PARTS OF
NORTHWEST TEXAS. A LOCALLY HIGHER SEVERE WEATHER THREAT WOULD
EXIST ACROSS OUR NORTHWEST COUNTIES WITH LARGE HAIL BEING THE MAIN
THREAT IF THESE STORMS DO DEVELOP.
AS THE COLD FRONT SAGS SOUTH LATER TONIGHT...RAIN AND THUNDERSTORM
CHANCES WILL PROGRESSIVELY SHIFT FARTHER SOUTH INTO CENTRAL TEXAS.
THE FRONT WILL LIKELY GET HUNG UP ACROSS THE HILL COUNTRY BY EARLY
FRIDAY MORNING. SCATTERED THUNDERSTORMS ARE AGAIN EXPECTED ALONG
THE FRONT WITH BEST CHANCES BEING ACROSS THE SOUTHERN COUNTIES.
WITH STEEP LAPSE RATES STILL IN PLACE ACROSS THIS AREA...SEVERE
HAIL WILL REMAIN A THREAT WITH THIS ACTIVITY. ACTIVITY TOMORROW
AFTERNOON SHOULD AGAIN DEVELOP INTO AN MCS AND HEAD SOUTHEAST OUT
OF THE AREA. FRONTAL BOUNDARY WOULD GET PUSHED FARTHER SOUTH BY
SATURDAY WITH POPS TAPERING BACK DOWN TO JUST 20 PERCENT ACROSS
THE SOUTHERN COUNTIES.
WITH THE MAIN UPPER LOW DRIFTING ACROSS NORTHWEST MEXICO OVER THE
WEEKEND...THERE SHOULD BE A FEW QUIET DAYS TO START NEXT WEEK. THE
UPPER LOW FINALLY GETS KICKED OUT BY MIDWEEK WITH ANOTHER SHOT OF
SHOWERS AND THUNDERSTORMS BY WEDNESDAY.
DUNN
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 76 66 79 59 77 / 90 60 20 20 10
WACO, TX 75 64 80 61 78 / 80 60 30 30 20
PARIS, TX 75 61 79 56 76 / 40 60 20 20 10
DENTON, TX 76 62 78 57 77 / 50 60 20 20 10
MCKINNEY, TX 75 62 78 57 78 / 60 60 20 20 10
DALLAS, TX 76 67 81 61 79 / 90 60 20 20 10
TERRELL, TX 77 63 80 58 78 / 70 60 20 20 10
CORSICANA, TX 75 65 80 61 77 / 80 60 30 30 20
TEMPLE, TX 75 64 80 60 76 / 80 60 50 30 20
MINERAL WELLS, TX 77 61 78 57 80 / 60 50 20 20 10
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
69/82
FOR FREQUENTLY ASKED QUESTIONS ABOUT THE AREA FORECAST DISCUSSION
VISIT...
HTTP://WEATHER.GOV/SALTLAKECITY/GENERAL/AFD_FAQS.PHP (ALL LOWER CASE)
AREA FORECAST DISCUSSION
NWS SPOKANE WA
615 PM PDT Fri May 10 2013
.SYNOPSIS...
Unseasonably warm and dry conditions will continue for the Inland
Northwest through Saturday. The warm temperatures will continue snow
melt in the mountains and higher river levels, particularly
across the northern mountains. Isolated thunderstorms will be possible
across the north and east mountains tonight and Saturday, mainly over
North Idaho. A cold front arriving late on Sunday will bring a
better chance of showers and more spring like temperatures into
early next week and even lower snow levels to higher mountain levels
temporarily on Tuesday. Snow melt will slow significantly next
with the cooler temperatures.
&&
.DISCUSSION...
Radar imagery as of 6 pm showed convection over the area had moved
out of the area...with some activity around Missoula with a second
cluster of showers near Yakima. The HRRR shows this activity
falling apart this evening and thus the forecast has been updated
to remove evening convection wording.
For overnight will be evaluating the potential for elevated
nocturnal convection near the Canadian Border of far NE Washington
and North Idaho. For now did not make any changes although current
models show this to be a marginal threat. Also will be looking at
an increase in mid and high clouds tonight as a low pressure
system off the coast slowly moves towards the area. A very warm
day today with with most locations reaching or coming within a few
degrees of record high temperatures combined with increased cloud
cover tonight will mean a mild night. Lows may have to be adjusted
upward especially over North Central Washington where cloud cover
will be thickest. However will await all of the 00z GFS and NAM
data before making changes to this part of the forecast. JW
&&
.AVIATION...
00Z TAFS: VFR to prevail at all TAF sites through 00Z Sunday.
Very weak trof passage spreads some mid and high clouds and
allows a slight nudge up in windspeeds and some slight wind
gusts primarily after 20Z. Isolated Thunderstorms ending by
02Z this evening and again small chance primarily in North
Idaho after 22Z Saturday. /Pelatti
&&
.PRELIMINARY POINT TEMPS/POPS...
Spokane 56 86 58 80 54 71 / 0 0 10 30 30 50
Coeur d`Alene 51 85 56 80 53 71 / 0 0 0 30 30 50
Pullman 50 84 56 79 51 71 / 0 0 0 20 40 50
Lewiston 56 90 61 86 58 78 / 0 0 10 20 40 40
Colville 48 90 53 84 51 73 / 0 0 10 40 30 50
Sandpoint 46 83 51 79 52 69 / 10 10 10 50 30 50
Kellogg 50 80 52 78 51 68 / 10 10 10 40 50 60
Moses Lake 54 92 61 85 55 78 / 0 0 10 20 20 30
Wenatchee 57 89 62 81 55 71 / 0 0 10 20 10 30
Omak 50 89 56 81 51 73 / 0 0 10 30 30 30
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...None.
&&
$$
AREA FORECAST DISCUSSION
NWS TALLAHASSEE FL
352 AM EDT Sat May 11 2013
.NEAR TERM [Today]...
The forecast today remains somewhat uncertain as much will depend on
the mesoscale evolution over the next 6-12 hours. The surface
pattern is quite muddled due to upstream MCS activity from Texas to
coastal Louisiana in the past day or two. Objective analysis places
a surface trough and convergence zone along the Louisiana coast,
extending east into the coastal waters adjacent to the FL Panhandle
coastline. Thunderstorms have developed early this morning just
north of the richer surface thetae (likely elevated slightly), and
ahead of an advancing mid-level MCV over coastal SW Louisiana. The
vast majority of both global and convection-allowing models (CAM)
had indicated a focused area of QPF near coastal Louisiana in the
12-18 UTC time frame, which means that things appear to be "ahead of
schedule" by a few hours. The model that seems to most closely
resemble reality right now (at 07 UTC) is the HRRR. Therefore, the
progression of PoPs and temperature trends closely follow the HRRR
and RAP models. For the forecast, this means we began increasing
rain chances in the western part of our area around 16-18 UTC
(around the noon hour), with an eastward progression from there
during the afternoon hours. High temperatures were kept highest in
the east, where cloud cover and rain will be last to arrive.
With respect to the intensity of thunderstorms, there is also a bit
of uncertainty. The initial SPC SWODY1 places us in 5% probabilities
of severe hail and wind. This seems reasonable given a lack of
clarity in the mesoscale details. The best chances of seeing a
strong or severe storm look to be where any sort of heating is able
to occur before cloud cover increases. In most of the available
models, areas that are able to get heating in the morning see about
1000-1500 j/kg of CAPE in the afternoon, with around 25-30 knots of
0-6km shear. It is in these favorable intersections of instability
and shear where a severe storm or two would be most likely. Impacts
would probably be rather isolated though. Assuming dewpoints in at
least the mid-60s, surface based (and the strongest) storms would be
most likely in areas that can get into the 80s temperature-wise.
&&
.SHORT TERM [Tonight through Monday]...
The 00 UTC NWP guidance continues to forecast an unusually deep
longwave trough over the eastern CONUS Sunday and Monday. The PoP
will decrease from northwest to southeast Sunday as dry air
advection develops. The highest PoP, 30-40%, will be from
Tallahassee southward and eastward tonight and Sunday, with the PoP
decreasing below 10% Sunday evening. The core of the cooler and
drier airmass won`t reach our forecast area until Monday. Highs on
Sunday will be in the lower 80s, but only in the 70s (below average)
Monday. Lows on Monday morning will be in the 50s (also below
average). The low humidity and relatively breezy conditions on
Monday will make it feel quite pleasant for mid May, when it usually
begins to get warm and humid.
&&
.LONG TERM [Monday Night through Friday]...
Deep layer ridging will build into the region for the middle of the
week followed by a low amplitude trough late Thursday into
Friday. There will be a slight to low end chance of rain on
Friday, otherwise the extended period will be dry. The week will
begin with below normal temperatures and gradually moderate to
seasonal levels by Thursday. The coldest temperatures will be
Tuesday morning when upper 40s to around 50 degrees are forecast.
&&
.AVIATION [Through 06 UTC Sunday]...
As some mid-high level cloud cover clears out of our area for the
last half of the overnight period (06-12 UTC), we are expecting some
patchy fog or low stratus to develop, with periodic reductions to
MVFR or IFR. Conditions should improve around 13-14 UTC. After that,
the outlook is VFR, although there may be some thunderstorms today
moving into the area from the west. Timing looks to be beginning
around 16-19 UTC at ECP and DHN, to as late as 21-00 UTC at VLD. In
any of the thunderstorms, brief reductions in the flight categories
would be expected, as well as the possibility of some gusty winds.
However, confidence in timing and location of storms is not high
enough to include in prevailing or TEMPO groups at this time.
&&
.MARINE...
Aside from the increased rain chances, weekend boaters will be
treated to low winds and seas (outside of scattered thunderstorms).
This will change Sunday night as the rather strong area of high
pressure builds across the Southeast behind a cold front, causing
winds to increase to 15 to 20 KT. These offshore winds may remain at
exercise caution levels through Tuesday morning.
&&
.FIRE WEATHER...
Wetting rains are expected over a good portion of the area today.
Drier air will arrive behind a cold front on Sunday Night with very
low RH for May expected on Monday. Despite the minimum RH around
25%, other fuel-dependent red flag criteria may not be met. Thus,
while red flag conditions seem somewhat uncertain, there is high
confidence that Monday will be a breezy, dry day with high
dispersion values.
&&
.HYDROLOGY...
The 00 UTC WPC 5-day rainfall accumulation forecast continues to
show our between one half and one inch over our forecast area,
mainly this weekend, and with the highest totals west of
Tallahassee. None of the experimental hydrologic ensembles forecast
minor flooding for our river forecast points over the next several
days. The maximum of maximum 6-hour QPF amounts from the various
Convection Allowing Models (CAM), a worst case scenario, show
isolated narrow bands of 3-4 inches. Neither the area coverage or
magnitude of these values would indicate enough of a threat for a
flash flood watch for today`s rain.
&&
.PRELIMINARY POINT TEMPS/POPS...
Tallahassee 83 66 82 53 80 / 70 40 30 10 0
Panama City 77 67 81 57 78 / 70 40 20 10 0
Dothan 81 63 79 50 78 / 70 40 10 0 0
Albany 85 64 81 50 76 / 60 40 10 0 0
Valdosta 86 64 81 52 77 / 70 40 30 10 0
Cross City 84 66 82 57 80 / 40 30 40 10 0
Apalachicola 79 67 79 59 76 / 60 30 30 10 0
&&
.TAE WATCHES/WARNINGS/ADVISORIES...
FL...None.
GA...None.
AL...None.
GM...None.
&&
$$
NEAR TERM...Lamers
SHORT TERM...Fournier
LONG TERM...Barry
AVIATION...Lamers
MARINE...Fournier
FIRE WEATHER...Lamers
HYDROLOGY...Fournier
AREA FORECAST DISCUSSION
NWS DES MOINES IA
354 AM CDT SAT MAY 11 2013
.SHORT TERM.../TODAY /...
ISSUED AT 325 AM CDT SAT MAY 11 2013
MAIN CONCERNS TODAY WILL BE SUBTLE PRECIP TRENDS AND WIND. UPPER
LEVEL TROUGH...INCLUDING POTENT ND/MN PV ANOMALY...CONTINUES TO
ADVANCE TOWARD THE GREAT LAKES EARLY THIS MORNING. WIDELY SCATTERED
LIGHT SHOWERS HAVE DEVELOPED AHEAD OF THIS FEATURE INTO IA AND ARE
PRIMARILY THERMODYNAMICALLY FORCED. LATEST RAP ANALYSIS SHOWS NICE
COLD FRONT ALOFT WITH RELATIVELY HIGHER BASED THETA-E ADVECTION AND
FRONTOGENETICAL FORCING. RESULTANT PRECIP IS HIGH BASED...TYPICALLY
7K FT OR HIGHER...AND STRUGGLING TO REACH THE GROUND MUCH.
EXTRAPOLATION SUGGESTS WHAT PRECIP THERE IS WILL ADVANCE SOUTH AND
EAST EXITING SE TOWARD 12Z. PRECIP OVER NRN MN IS NOT EXPECTED TO
AFFECT OUR FORECAST AREA BY AFTERNOON DUE TO TRAJECTORIES AND
INCREASING SUBSIDENCE. SOUNDINGS SHOW SOME POTENTIAL FOR SURFACE
BASED REDEVELOPMENT BUT ADEQUATE MOISTURE IS CERTAINLY QUESTIONABLE.
08Z SURFACE ANALYSIS SHOWS INITIAL WIND SHIFT/TROUGH ALONG
CARROLL-WEBSTER CITY-MASON CITY LINE WITH TRUE COLD FRONT SEEMING TO
LACK BEHIND JUST REACHING IA/MN BORDER. MOS GUIDANCE AND SOUNDINGS
SUGGEST WIND WILL INCREASE WITH MIXING TODAY...APPROACHING SUSTAINED
ADVISORY CRITERIA /26 KTS/ NORTHEAST. SOUNDINGS DEPICT MIXING TO
2KM OR MORE BY AFTERNOON WITH MIXED LAYER WINDS SUGGESTING GUSTS
INTO THE LOW 30S /KTS/ NE THIRD.
MAX TEMPS ARE GENERALLY AT OR BELOW MOS GUIDANCE EVEN WITH THIS DEEP
MIXING. THESE SOUNDINGS STRUGGLE TO REACH MOS...LIKELY DUE TO
INFLUENCE OF CLIMO. DEWPOINTS WILL ALSO BE QUITE LOW...DROPPING INTO
THE 20S DUE TO UPSTREAM AIRMASS AND MIXING. MODEL SKIN DEWPOINTS
SEEM TOO HIGH...LIKELY OVERDONE DUE TO EVAPOTRANSPIRATION BEING
BEHIND SCHEDULE.
.LONG TERM.../TONIGHT THROUGH FRIDAY/...
ISSUED AT 325 AM CDT SAT MAY 11 2013
A SOMEWHAT HIGH AMPLITUDE UPPER AIR PATTERN INITIALLY GIVES WAY TO
A MORE ZONAL...OR AT LEAST A LOWER AMPLITUDE UPPER PATTERN BY
THE MIDDLE OF NEXT WEEK. AN UPPER RIDGE OVER THE PACIFIC NORTHWEST
BUILDS INTO THE NORTHERN PLAINS BY TUESDAY. AS IT RIDGE MOVES
EAST...IT IS FLATTENED BY A SHORTWAVE MOVING OVER THE RIDGE ACROSS
SOUTHERN CANADA. MEANWHILE...AN OLD UPPER LOW INITIALLY OVER
NORTHWEST MEXICO EJECTS INTO THE CENTRAL PLAINS AND GETS ABSORBED
INTO THE WESTERLIES. THE SHORT RANGE MODELS ARE IN FAIR AGREEMENT
WITH THE EVALUATION OF THE PATTERN THROUGH TUESDAY. AFTER
TUESDAY...THE 00Z GFS/ECMWF START TO DIVERGE WITH THE DETAILS OF
THE UPPER PATTERN AND ASSOCIATED SURFACE REFLECTION. THE 00Z GFS
HAS MORE AMPLITUDE ALLOWING THE SURFACE FRONT TO MOVE SOUTH OF
IOWA BY MIDWEEK. THE ECMWF HAVING A FLATTER LOOKING PATTERN NEVER
PUSHES THE BOUNDARY THROUGH THE STATE BEFORE LIFTING IT BACK NORTH
LATE IN THE WEEK.
THE SHORT RANGE MODELS ARE IN GOOD AGREEMENT CONCERNING THE
POSITION OF THE POLAR SURFACE HIGH OVER THE MISSOURI VALLEY BY 12Z
SUNDAY. IT WOULD APPEAR THAT A GOOD RADIATION COOLING SCENARIO
SHOULD OCCUR OVER WESTERN IOWA SUNDAY MORNING. WITH LIGHT WINDS
AND LOWS APPROACHING FREEZING...WILL ISSUE A FROST ADVISORY FOR
PART OF WESTERN AND NORTHERN SECTIONS OF THE FORECAST AREA. SOME
CONCERN ABOUT LOW DEWPOINTS...BUT WHERE THE WIND IS VERY
LIGHT...THERE SHOULD BE ENOUGH FROST FORMATION TO WARRANT
ADVISORY.
NEXT UP WILL BE THE RAPID WARM UP EARLY NEXT WEEK AS BEFORE MENTION
UPPER RIDGE MOVES ACROSS THE NORTHERN CONUS. MODELS ARE IN GOOD
AGREEMENT WITH VERY WARM 850 MB TEMPERATURES ON TUESDAY IN THE
WARM SECTOR AHEAD OF THE APPROACHING COLD FRONT. BASICALLY USED THE
PREVIOUS FORECAST FOR HIGHS WHICH LOOK ON TARGET.
THE PATTERN LOOKS MORE ACTIVE CONCERNING THUNDERSTORMS FROM THE
MIDDLE OF NEXT WEEK THROUGH THE END OF THE FORECAST PERIOD. THERE
SHOULD BE AN WEST TO EAST BOUNDARY IN THE AREA WHICH IS
COSMOLOGICALLY SUPPORTS THUNDERSTORM CHANCES.
&&
.AVIATION...11/06Z
ISSUED AT 1155 PM CDT FRI MAY 10 2013
CDFNT NEAR A KMSP-KGRI LINE WILL PUSH SOUTHEAST NEAR 40 KTS ACROSS
THE STATE TONIGHT. ISOLATED SHOWERS WILL ACCOMPANY THE FRONT WITH
GUSTY NWLY WINDS BEHIND THE FRONT. CONDITIONS WILL REMAIN VFR
THROUGH THE TAF PERIOD. HIGH PRESSURE BUILDING INTO THE STATE SAT
NIGHT WILL CAUSE WINDS TO DROP OFF QUICKLY AT SUNSET.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...
FROST ADVISORY FROM 3 AM TO 9 AM CDT SUNDAY FOR AUDUBON-CALHOUN-
CARROLL-CASS-CERRO GORDO-CRAWFORD-EMMET-GREENE-GUTHRIE-HANCOCK-
HUMBOLDT-KOSSUTH-PALO ALTO-POCAHONTAS-SAC-WEBSTER-WINNEBAGO-
WORTH-WRIGHT.
&&
$$
SHORT TERM...SMALL
LONG TERM...JOHNSON
AVIATION...MS MAY 13
AREA FORECAST DISCUSSION...UPDATED
NWS PADUCAH KY
1144 PM CDT FRI MAY 10 2013
.UPDATE...
ISSUED AT 1139 PM CDT FRI MAY 10 2013
UPDATED THE AVIATION SECTION FOR THE 06Z TAF ISSUANCE.
&&
UPDATE ISSUED AT 809 CDT FRI MAY 10 2013
MAIN ADJUSTMENT EARLY THIS EVENING IS THE TIMING/LOCATION OF THE
CURRENT CONVECTIVE ACTIVITY /SHOWERS AND THUNDERSTORMS/...AS WELL
AS THE ATTENDENT WIND AND TEMPERATURE FIELDS BEHIND THE COLD
FRONT. THE 3KM HRRR GUIDANCE...SPATIALLY ADJUSTED...APPEARS TO BE
HANDLING THE STORM SCALE DEVELOPMENT FAIRLY WELL THROUGH MIDNIGHT.
GIVEN THE POST-FRONTAL CLOUD COVER AND LIMITED EROSION OF THIS
CLOUD COVER DUE TO LOW AMPLITUDE COLD AIR ADVECTION...FOG
POTENTIAL SHOULD REMAIN MINIMAL OVER THE WFO PAH FORECAST AREA.
UPDATE ISSUED AT 637 PM CDT FRI MAY 10 2013
UPDATED THE AVIATION SECTION FOR THE 00Z TAF ISSUANCE.
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY NIGHT)
ISSUED AT 258 PM CDT FRI MAY 10 2013
THE COLD FRONT HAS YET TO REALLY PUSH INTO THE FORECAST AREA AS OF
1930Z. A PRE-FRONTAL WIND SHIFT HAS FOCUSED SOME SCATTERED
CONVECTION ON A LINE FROM NEAR KPOF TO KMWA...BUT IT HAS ONLY
GENERATED SPORADIC LIGHTNING. LAPS INDICATES THAT THE MOST
UNSTABLE SURFACE AIRMASS IS OVER FAR SOUTHEAST MISSOURI AND
SOUTHWEST KENTUCKY...SO WOULD EXPECT THAT CONVECTION TO PROGRESS
SOUTHEAST THROUGH 00Z. ANOTHER BAND OF SHOWERS WILL PUSH THROUGH
THE KOWB AREA IN THE NEXT HOUR OR SO.
WILL TAKE THE EASY WAY OUT AND JUST MOVE AN AREA OF LIKELY POPS
SOUTHEAST THROUGH WEST KENTUCKY THROUGH SUNSET...ALTHOUGH WITH THE
VERY SLOW SPEED OF MOVEMENT OF BOUNDARIES AND CONVECTIVE
ELEMENTS...COULD SEE IT FALLING APART BEFORE REACHING THE FAR
SOUTHEAST PORTIONS OF THE FORECAST AREA.
WILL QUICKLY DIMINISH POPS FROM NORTHWEST TO SOUTHEAST THROUGH THE
FIRST PART OF THE EVENING...BUT THE FRONT WILL LAG BEHIND THIS
EVENING...NOT CLEARING THE ENTIRE AREA UNTIL AROUND 06Z.
FOR SATURDAY...THE MODELS HAVE CONTINUED THEIR AGGRESSIVE TREND IN
BRING A BAND OF SHOWERS AND POSSIBLY THUNDERSTORMS THROUGH THE
AREA ALONG A SECONDARY FRONT. THIS FRONT WILL BE QUITE STRONG AND
SHALLOW...SO WOULD EXPECT IT TO MAKE QUICKER PROGRESS THROUGH THE
AREA. HAVE A BAND OF 20-40 POPS MOVING SOUTHWARD THROUGH THE
FORECAST AREA THROUGH THE AFTERNOON. WILL EVEN LINGER A SLIGHT
CHANCE OF SHOWERS OVER WEST KENTUCKY INTO THE EVENING.
GOOD COLD...DRY ADVECTION IS EXPECTED SATURDAY NIGHT AND
SUNDAY. THE SURFACE HIGH WILL SETTLE OVER THE SUNDAY NIGHT...WHICH
WILL RESULT IN EXCELLENT RADIATIONAL COOLING CONDITIONS. THE
MODELS ARE TRENDING COLDER SUNDAY NIGHT...AND THE CONSENSUS TAKES
DEWPOINTS INTO THE LOWER AND MIDDLE 30S. SO.......LOWS IN THE 30S
AND AT LEAST SOME PATCHY FROST SEEM TO BE LIKELY FOR MUCH OF THE
AREA. HAVE LOOKED AT IT FOR 5 DAYS NOW AND THIS IS BY FAR THE
COOLEST THE MODELS HAVE GONE. HAVE LITTLE REASON TO NOT BELIEVE
IT AT THIS POINT.
.LONG TERM...(MONDAY THROUGH FRIDAY)
ISSUED AT 258 PM CDT FRI MAY 10 2013
HIGH PRESSURE WILL USHER IN A MUCH COOLER AND DRIER AIR MASS SUNDAY.
WE EXPECT LOWS AROUND 40 BOTH SUNDAY AND MONDAY MORNINGS WITH MONDAY
THE COOLEST...SECOND DAY AFTER FRONTAL PASSAGE IS USUALLY THE
COOLEST AS A RULE OF THUMB. PATCHY FROST CAN NOT BE RULED OUT AT
THIS TIME BUT WITH CURRENT PROJECTIONS WOULD BE VERY LIMITED AND NOT
WIDESPREAD. HOWEVER WILL MONITOR CLOSELY FOR ANY REVISIONS.
SOUTHERLY FLOW RETURNS ON THE BACKSIDE OF THE HIGH NEXT WEEK WHICH
WILL BEGIN A WARMING TREND. MODELS ARE IN GOOD AGREEMENT THE NEXT
STORM SYSTEM WILL DEVELOP OVER SW US AND DRIVE NE ACROSS THE
PLAINS...REACHING THE HEARTLAND LATE IN THE WEEK. THE LAST COUPLE
GFS RUNS TRY TO PHASE THIS A COLD FRONT APPROACHING FROM THE
NORTH...HOWEVER THE ECMWF STALLS THE FRONT TO THE NORTH AND BRINGS
THE LOW IN A LITTLE SLOWER BUT PAINTS QPF OVER THE AREA AS WELL JUST
A LITTLE LATER. FOR NOW PLAN TO LEAN TOWARD THE SLOWER ECMWF AND
HOLD PRECIP OFF UNTIL POSSIBLY THURSDAY AND MAY END UP HOLDING UNTIL
THURSDAY NIGHT AS THAT SYSTEM BECOMES CLOSER WITH TIME. HOWEVER WILL
WAIT AND SEE WHAT THE EXTENDED INIT PRODUCES AND COLLABORATE WITH
SURROUNDING OFFICES FOR THE BEST FIT OR TIME FRAME FOR NEXT WEEKS
STORM SYSTEM.
&&
.AVIATION...
ISSUED AT 1139 PM CDT FRI MAY 10 2013
MVFR CIGS WILL PREVAIL AT ALL SITES THROUGH 15-16Z...THEN VFR
CONDITIONS THROUGH THE END OF THE PERIOD. NORTHERLY WINDS AOB 10
KTS WILL INCREASE TO 12-14 KTS WITH GUSTS UP TO 24 KTS AFT 00Z.
&&
.PAH WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
MO...NONE.
IN...NONE.
KY...NONE.
&&
$$
AVIATION...JP
PUBLIC...SMITH
AREA FORECAST DISCUSSION
NWS NEW ORLEANS LA
326 AM CDT SAT MAY 11 2013
.SHORT TERM...SEVERAL MORE ROUNDS OF SHOWERS AND THUNDERSTORMS
REMAIN BEFORE A SLOW MOVING COLD FRONT PUSHES OFFSHORE TONIGHT. AN
UPPER LEVEL TROUGH AXIS HAS A HOLD ON THE REGION. SEVERAL FAST MOVING
PERTURBATIONS MOVE ALONG THE AXIS PROVIDING THE INSTABILITY TO
KICK HEAVY RAIN. IR SATELLITE SHOWS 2 SUCH IMPULSES POISED TO MOVE
THROUGH. THE FIRST IS ASSOCIATED WITH THE RAIN INDICATED ON RADAR
IN SW LA AND THE OTHER FURTHER WEST IN S TX. EXPECT THE FIRST
IMPULSE TO BRING HEAVY RAIN THIS MORNING AND THE 2ND TO BRING
ANOTHER ROUND OF HEAVY RAIN LATER THIS MORNING ON INTO THE
AFTERNOON HOURS.
PREVIOUS SOUNDING MEASURED A PW OF 1.58 WITH VERY LITTLE TEMP DEW
POINT SPREADS THROUGH 35K FEET. GFS AND ECMWF HAVING SOME
DIFFICULTY HANDLING THE SITUATION...SEEMS MESO MODELS INITIALIZING
BETTER PER WSR88D. GFS HAS THE BULK OF THE RAIN FURTHER SOUTH THAN OTHER
MODEL SOLUTIONS. THE RUC SEEMS TO HAVE THE BEST HANDLE ON THIS
EVENT WITH A 850 THETA E RIDGE MOVING FROM NORTH FROM THE COAST.
EXPECT THE CONVECTION AND HEAVY RAIN TO FOLLOW THE THETA E AXIS.
MESO MODELS ALSO SHOW INCREASING UPPER LEVEL DIVERGENT FLOW WITH
SOME DEGREE OF SFC CONVERGENCE. THE THETA E AXIS... IMPULSE
INDUCED LIFT...UPPER LEVEL DIVERGENCE AND LOW LEVEL CONVERGENCE
ALL ADD UP TO THE POTENTIAL OF HEAVY RAIN. FFG VALUES AVERAGE OUT
TO BE AROUND 1.6 TO 2.1 INCHES AN HOUR FOR MOST LOCATIONS. HOWEVER...
SEVERAL LOCATIONS ARE AT PARTICULAR RISK WITH .5 INCHES FOR AN
HOUR AND EVEN .6 INCHES IN A 6 HOUR PERIOD. RAIN ALONG THE COASTAL
LA PARISHES SUCH AS TERREBONNE AND LAFOURCHE WILL CAUSE FLASH
FLOOD ISSUES EXPANDING TO OTHER AREAS TODAY. ROUND ONE WILL BEGIN
AROUND 10Z WITH ROUND TWO NEAR 17Z.
THE COLD FRONT WILL PUSH THROUGH TONIGHT AND WILL BRING COOLER AND
DRIER AIR INTO THE ENTIRE AREA.
.LONG TERM...
WE HAVE A CHANCE TO DRY OUT SUNDAY THROUGH MID WEEK. AN UPPER
TROUGH DIGS INTO THE AREA WED NIGHT AND INTO THURSDAY BRINGING
RAIN CHANCES BACK INTO THE FORECAST. SO FAR... THIS SYSTEM DOES
NOT APPEAR TO BE AS MOIST AND PROLONGED AS THE PREVIOUS. LOOKS LIKE
DIURNAL CONVECTION IS POSSIBLE LATE IN THE WEEK.
&&
.MARINE...THE PRESSURE GRADIENT HAS WEAKENED SOME AS THE COLD FRONT
DRIFTS EVER CLOSER TO THE REGION. WEAK TO MODERATE ONSHORE FLOW WILL
GENERALLY CONTINUE THROUGH THE DAY BUT THE FRONT WILL FINALLY PUSH
INTO THE GULF OVERNIGHT AND WINDS WILL BECOME NRLY BEHIND IT.
MODERATE OFFSHORE WINDS ARE EXPECTED TOMORROW BUT AS HIGH PRESSURE
PUSHES INTO THE LOWER MS VALLEY THE PRESSURE GRADIENT WILL TIGHTEN
ACROSS THE NCNTRL AND NERN GULF AND THIS COULD LEAD TO STRONG
OFFSHORE WINDS OVERNIGHT SUN BEFORE FINALLY RELAXING MON AS HIGH
PRESSURE FINALLY SITS IN RIGHT OVER THE AREA. LGT WINDS ARE THEN
EXPECTED THROUGH THE MIDDLE OF THE WEEK AS HIGH PRESSURE DOMINATES
THE REGION. /CAB/
&&
.AVIATION...ALL SORTS OF AVIATION ISSUES THIS MORNING. MOST
TERMINALS ARE DEALING WITH CIG OR VSBY REDUCTIONS OR BOTH.
TERMINALS ARE RANGING FROM MVFR TO IFR WITH VSBYS GENERALLY B/T 2
AND 5SM AND CIGS FROM AS LOW AS 600 TO 5K FT. UNTIL CONVECTION MOVES
BACK IN NOT EXPECTING CONDITIONS TO CHANGE MUCH BESIDES BOUNCE
BETWEEN IFR AND MVFR...EVEN TEMPORARILY DROPPING TO LIFR AT TIMES.
CONVECTION SHOULD BEGIN TO IMPACT BTR B/T 915 & 945Z WITH EACH
TERMINAL TO THE EAST SEEING CONVECTION IN UNDER AND HOUR OR 2
AFTERWARD. CURRENT TIMING HAS MSY SEEING CONVECTION NEAR
1030-1045Z. OF COURSE CIGS AND VSBYS WILL BE REDUCED SIGNIFICANTLY
WITH THE CONVECTION AND FREQUENT LIGHTNING WILL BE AN ISSUE AGAIN.
WIND GUSTS WILL BE A PROBLEM BUT DO NOT APPEAR TO BE AS MUCH OF AN
ISSUE AS THEY WERE YESTERDAY. CONVECTION SHOULD FINALLY CLR OUT
AFTER 20Z. /CAB/
&&
.DECISION SUPPORT...
DSS CODE...YELLOW.
DEPLOYED...NONE.
ACTIVATION...NONE.
ACTIVITIES...SLURRY SUPPORT
MONITORING RIVERS
MONITORING CONVECTION FOR SEVERE AND FLASH FLOODING
DECISION SUPPORT SERVICES (DSS) CODE LEGEND
GREEN = NO WEATHER IMPACTS THAT REQUIRE ACTION
BLUE = LONG FUSED WATCH/WARNING/ADVISORY IN EFFECT OR HIGH
VISIBILITY EVENT
YELLOW = HEIGHTENED IMPACTS WITH SHORT FUSED
WATCH/WARNING/ADVISORY ISSUANCES; RADAR SUPPORT
ORANGE = HIGH IMPACTS - SLIGHT TO MODERATE RISK SEVERE; NEARBY
TROPICAL EVENTS; HAZMAT OR OTHER LARGE EPISODES
RED = FULL ENGAGEMENT FOR MODERATE TO HIGH RISK SVR
AND/OR DIRECT TROPICAL THREATS; EVENTS OF NATIONAL
SIGNIFICANCE
&&
.PRELIMINARY POINT TEMPS/POPS...
MCB 77 55 78 49 / 80 20 10 10
BTR 79 57 79 51 / 80 20 10 10
ASD 78 58 78 51 / 80 30 10 10
MSY 77 63 78 57 / 80 30 10 10
GPT 77 59 78 52 / 80 40 10 10
PQL 79 58 78 50 / 80 40 10 10
&&
.LIX WATCHES/WARNINGS/ADVISORIES...
LA...FLASH FLOOD WATCH UNTIL 1 AM SUNDAY FOR THE FOLLOWING ZONES:
ASCENSION...ASSUMPTION...EAST BATON ROUGE...EAST
FELICIANA...IBERVILLE...LIVINGSTON...NORTHERN
TANGIPAHOA...ORLEANS...POINTE COUPEE...SOUTHERN
TANGIPAHOA...ST. CHARLES...ST. HELENA...ST. JAMES...ST.
JOHN THE BAPTIST...ST. TAMMANY...UPPER JEFFERSON...UPPER
LAFOURCHE...UPPER PLAQUEMINES...UPPER ST. BERNARD...UPPER
TERREBONNE...WASHINGTON...WEST BATON ROUGE...AND WEST
FELICIANA.
GM...NONE.
MS...FLASH FLOOD WATCH UNTIL 1 AM SUNDAY FOR THE FOLLOWING ZONES:
AMITE...HANCOCK...HARRISON...JACKSON...PEARL
RIVER...PIKE...WALTHALL...AND WILKINSON.
GM...NONE.
&&
$$
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
1131 PM CDT FRI MAY 10 2013
.UPDATE...
ISSUED AT 905 PM CDT FRI MAY 10 2013
BACK EDGE OF LOW CLOUD DECK IS CURRENTLY NEAR A VERSAILLES...
BOONEVILLE...MOUNT PLEASANT IOWA LINE. EXTRAPOLATION SUGGESTS A
SE MOVEMENT OF 15-20KTS...A BIT FASTER THAN EARLIER EXPECTED.
SO...THIS UPDATE CLEAR SKIES A BIT MORE RAPIDLY...WITH A
CORRESPONDING DIP IN MIN TEMPS ESPECIALLY OVER THE NW HALF OF THE
CWA. WILL CARRY DRIZZLE FOR A FEW MORE HOURS IN OUR S
COUNTIES...PRIMARILY S AND SE OF STL.
TRUETT
&&
.SHORT TERM...(TONIGHT THROUGH SATURDAY)
ISSUED AT 328 PM CDT FRI MAY 10 2013
THE FIRST SHOT OF COOLER AIR HAS OVERSPREAD THE AREA WITH THE
ASSOCIATED COLD FRONT NOW ACROSS EXTREME SOUTHEAST MISSOURI AND
SOUTHERN ILLINOIS. EXTENSIVE STRATUS BLANKETS MUCH OF THE AREA AND
EXTENDS WELL NORTH INTO EASTERN IOWA AT MID AFTERNOON. THE MODELS
VARY ON HOW QUICKLY TO CLEAR THE LOW CLOUDS...AND I HAVE SIDED
WITH THE SLOWER RUC AND LOCAL WRF WITH SLOW CLEARING FROM NORTH TO
SOUTH TONIGHT...AND THE SOUTHEAST CWA NOT CLEARING UNTIL AFTER
DAYBREAK ON SATURDAY. A SERIES OF POWERFUL SHORT WAVES NOW ACROSS
MANITOBA AND SASKATCHEWAN WILL DIG SOUTHEASTWARD TONIGHT WITH A
CLOSED LOW EVOLVING. THIS UPPER LOW/TROF WILL CONTINUE TO DEEPEN
WITH A BROAD DEEP LONGWAVE TROF EVOLVING ACROSS THE EASTERN CONUS
BY SATURDAY NIGHT. INTIALLY IN THE PROCESS...THE DIGGING TROF
WILL DRIVE A COLD FRONT ACROSS THE AREA ON SATURDAY. THIS FRONT
WILL USHER A MORE POTENT BLAST OF CHILLY AIR INTO THE REGION ON
THE ORDER OF 2-3 STANDARD DEVIATIONS BELOW NORMAL. IT STILL LOOKS
LIKE THERE WILL BE A CHANCE OF SHOWERS AND EVEN SOME THUNDERSTORMS
FORMING ALONG THE FRONT AS IT MOVES QUICKLY SOUTHEASTWARD. THE
FORCING APPEARS TO BE LARGELY FRONTAL AND THIS SUGGESTS SCATTERED
COVERAGE. INSTABILITY WILL BE WEAK...PROBABLY OVERDONE ON THE NAM
OWING TO TOO HIGH SURFACE DEW POINTS...BUT STILL GREAT ENOUGH TO
SUPPORT A THUNDER THREAT. IT WILL BE A NARROW 1-2 HOUR WINDOW FOR
PRECIPITATION OCCURING WITH THE FRONT AND THEN GUSTY NW WINDS IT
ITS WAKE.
GLASS
.LONG TERM...(SATURDAY NIGHT THROUGH NEXT FRIDAY)
ISSUED AT 328 PM CDT FRI MAY 10 2013
THE DEEP LONGWAVE TROF WILL DOMINATE THE PATTERN AND CONTROL THE
SENSIBLE WEATHER SATURDAY NIGHT INTO EARLY MONDAY WITH A COOL
SURFACE HIGH PREVAILING. BELOW AVERAGE TEMPERATURES WILL BE THE
RULE AND SOME RECORDS COULD BE APPROACHED ON SUNDAY MORNING. THERE
COULD ALSO BE SOME PATCHY FROST WHERE LOWS DIP INTO THE MID 30S.
THE SURFACE HIGH MOVE ACROSS THE AREA ON SUNDAY AND GRADUALLY
RETREAT SOUTHEAST SUNDAY NIGHT INTO THE WESTERN TN VALLEY. THIS
SUGGESTS THAT THE COOLEST TEMPERATURES ON SUNDAY NIGHT AND MONDAY
MORNING WILL BE ACROSS THE EASTERN OZARKS AND SW ILLINOIS WHERE
LOWS IN THE MID-UPPER 30S AND PATCHY FROST WILL ONCE AGAIN BE
POSSIBLE. LOW LEVEL WAA WILL THEN COMMENCE ON MONDAY AND THIS
SHOULD LEAD TO A NICE REBOUND IN TEMPERATURES AS THE LOWER
TROPOSPHERIC FLOW BECOMES MORE SOUTHERLY.
SAY GOODBYE TO THE COOL...I THINK FOR GOOD...BY TUESDAY. THE LONGWAVE
TROF DEPARTS OFF THE EAST COAST AND HEIGHTS RISE ALOFT AS A SHORT
WAVE RIDGE BUILDS INTO THE MS VALLEY. STRONG WAA WILL PROGRESS AND
H85 TEMPS ARE FORECAST TO RISE ABOVE +18 DEGC ON ALL THE GUIDANCE...
SUPPORTING HIGHS WELL INTO THE 80S. MOISTURE AND CLOUDS WILL BEGIN
TO INCREASE LATE WEDNESDAY AS A NEW UPSTREAM TROF MOVES ACROSS THE
PLAINS AND EVENTUALLY INTO THE MS VALLEY BY THURSDAY. THE MODELS
DISAGREE ON WHETHER AN EAST-WEST FRONT WILL ALSO DROP INTO THE
AREA DURING THIS TIME...BUT THE PRESENCE OF THE UPPER TROF ALONE
SUPPORTS A CHANCE OF SHOWERS AND THUNDERSTORMS DURING THE LATER
PART OF THE WEEK.
GLASS
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1130 PM CDT FRI MAY 10 2013
CLOUDS SCATTERING OUT A BIT FASTER THAN ORIGINALLY THOUGHT...SO
ADJUSTED ACCORDINGLY. OTHERWISE...WINDS TO BECOME LIGHT AND VARIABLE.
SECONDARY FRONTAL BOUNDARY TO SLIDE THROUGH FORECAST AREA BY
MIDDAY TODAY...MOVING THROUGH KUIN BY 13Z...KCOU BY 14Z AND METRO
AREA BY 16Z. SOME WEAK INSTABILITY WITH BOUNDARY...BUT CHANCES OF
SHOWERS AND A FEW THUNDERSTORMS HARD TO PIN DOWN. SO JUST KEPT
VCNTY SHOWER MENTION/VFR CIGS FOR A FEW HOURS AFTER FRONTAL PASSAGE.
OTHERWISE...WINDS TO PICKUP BEHIND THE FRONT FROM THE NORTHWEST
WITH GUSTS NEAR 25KTS AT TIMES. THEN WINDS DIMINISH AFTER SUNSET
AND SKIES CLEAR OUT.
SPECIFICS FOR KSTL...CLOUDS SCATTERING FROM WEST TO EAST...SO
SHOULD STILL SCATTER OUT IN METRO AREA BY 09Z. OTHERWISE...WINDS TO
BECOME LIGHT AND VARIABLE. SECONDARY FRONTAL BOUNDARY TO SLIDE
THROUGH METRO AREA BY 16Z. SOME WEAK INSTABILITY WITH
BOUNDARY...BUT CHANCES OF SHOWERS AND A FEW THUNDERSTORMS HARD TO
PIN DOWN. SO JUST KEPT VCNTY SHOWER MENTION/VFR CIGS THROUGH 19Z.
OTHERWISE...WINDS TO PICKUP BEHIND THE FRONT FROM THE NORTHWEST
WITH GUSTS NEAR 25KTS AT TIMES. THEN WINDS DIMINISH AFTER 03Z
SUNDAY AND SKIES CLEAR OUT.
BYRD
&&
.CLIMATE...
ISSUED AT 328 PM CDT FRI MAY 10 2013
RECORD LOWS
5/125/13
ST LOUIS39 (1960)40 (1971)
COLUMBIA35 (1892)34 (1901)
QUINCY35 (1960)35 (1971)
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
1140 PM CDT FRI MAY 10 2013
.DISCUSSION...
SEE THE 06Z AVIATION DISCUSSION BELOW.
&&
.AVIATION...
MID LEVEL CLOUDS CONTINUE TO STREAM ACROSS THE REGION AND WILL DO
SO FOR MUCH OF THE PERIOD AS THE UPPER CYCLONE SPINS OVER NORTHERN
MEXICO. A FEW HIGH BASED ECHOES REPRESENT VERY LIGHT SHOWERS THAT
MAY CAUSE A FEW SPRINKLES OVERNIGHT BUT THIS SHOULD HAVE MINIMAL
IMPACT. HOWEVER...THE HI RES CONVECTION MODELS INDICATE THAT
ISOLATED ELEVATED CONVECTION MAY DEVELOP LATE TONIGHT OVER THE
SOUTHERN HALF OF THE CWA. I HAVE LEFT THE TAFS DRY GIVEN THE HIGH
UNCERTAINTY BUT DID INCLUDE A FEW CLOUDS AROUND 4000 FT BY 12Z AT
KSJT. OTHERWISE...WE WILL SEE THE BEST RAIN CHANCES TOMORROW ALONG
THE I-10 CORRIDOR FROM KSOA TO KJCT...MAINLY DURING THE DAYTIME
HOURS. VFR CONDITIONS WILL PREVAIL WITH THE EXCEPTION BEING
TEMPORARY REDUCTIONS IN VIS/CEILINGS IN AND AROUND ANY STORMS
THAT MAY DEVELOP. EXPECT LIGHT NORTH WINDS OVERNIGHT BECOMING
NORTHEAST AT 10-12 KTS FOR SATURDAY.
JOHNSON
&&
.PREV DISCUSSION... /ISSUED 847 PM CDT FRI MAY 10 2013/
UPDATE...
SEE UPDATE DISCUSSION BELOW.
DISCUSSION...
UPDATED ZONES AND GRIDS TO REDUCE POPS TO SLGT CHC AND REMOVE
THUNDER FOR TONIGHT.
21
PREV DISCUSSION... /ISSUED 718 PM CDT FRI MAY 10 2013/
UPDATE...
SEE UPDATE DISCUSSION BELOW.
DISCUSSION...
UPDATED ZONES AND HAZARD GRID TO CANCEL SEVERE THUNDERSTORM WATCH
#156. ALSO...UPDATED HOURLY TEMPS DUE TO CURRENT READINGS IN THE
60S ACROSS MUCH OF THE AREA.
21
PREV DISCUSSION... /ISSUED 617 PM CDT FRI MAY 10 2013/
DISCUSSION...
SEE 00Z AVIATION DISCUSSION BELOW.
AVIATION...
SCATTERED TSTMS CURRENTLY OVER THE HEARTLAND AND NORTHWEST HILL
COUNTRY WILL EXIT THE AREA BY 01Z. ISOLD TSTMS WILL STILL BE
POSSIBLE THIS EVENING MAINLY SOUTH OF THE I-20 CORRIDOR. HAVE A
VCTS GOING AT THE KJCT AND KBBD TERMINALS THROUGH 02Z. OTHERWISE
MAINLY VFR CONDITIONS ARE EXPECTED THE NEXT 24 HOURS...WITH
ABUNDANT HIGH CLOUDS OVER WEST CENTRAL TEXAS. WINDS WILL BE NORTH
WITH GUSTS TO NEAR 30 KNOTS THROUGH 02Z AT THE KSOA AND KBBD
TERMINALS.
21
PREV DISCUSSION... /ISSUED 322 PM CDT FRI MAY 10 2013/
SHORT TERM...
BAND OF STRONG TO SEVERE THUNDERSTORMS IN THE CONCHO VALLEY
SOUTHWEST INTO CROCKETT COUNTY...ASSOCIATED WITH A COLD
FRONT...WAS STEADILY MOVING SOUTHEAST THIS AFTERNOON. A SEVERE
THUNDERSTORMS WATCH IS IN EFFECT FOR MUCH OF WEST CENTRAL
TEXAS...SOUTH OF THE BIG COUNTRY UNTIL 10 PM CDT TONIGHT.
ATMOSPHERE WAS UNSTABLE THIS AFTERNOON AS COLDER AIR
ALOFT...ASSOCIATED WITH AN UPPER LEVEL TROUGH OVER NEW MEXICO
MOVED EAST. SPC RAP SB CAPES WERE 1500-2500 J/KG. THIS IS LOWER
THAN YESTERDAY...BUT STILL ENOUGH TO GET GOLF BALL SIZE HAIL IN
COKE COUNTY FROM A SUPERCELL THIS AFTERNOON.
SEVERE STORM ACTIVITY SHOULD NOT BE QUITE AS EXTENSIVE AS
YESTERDAY...AND SHOULD WEAKEN BY SUNSET WITH LOSS OF DAYTIME
HEATING AND PASSAGE OF THE COLD FRONT.
STILL KEEPING A CHANCE OF SHOWERS AND THUNDERSTORMS SATURDAY AS
THE UPPER TROUGH MOVES ACROSS THE REGION. DRIER AIR WILL ALSO MOVE
IN FROM NORTH TO SOUTH...SO SEVERE THUNDERSTORMS ARE NOT EXPECTED.
MOST STORMS SHOULD BE ALONG THE I-10 CORRIDOR AND END BY LATE
AFTERNOON.
04
LONG TERM...
SHOWER AND THUNDERSTORM CHANCES RETURN TUESDAY AS A CUT OFF UPPER
LOW OVER BAJA CALIFORNIA MOVES NORTHEAST AND WEAKENS OVER NEW
MEXICO AND THE TEXAS PANHANDLE. MOVEMENT AND PLACEMENT OF CUT OFF
UPPER LOWS HAS ALWAYS BEEN DIFFICULT...ESPECIALLY WHEN THEY KICK
OUT. WILL KEEP POPS FAIRLY LOW AT THIS TIME...IN THE 20 TO 30
PERCENT RANGE...WITH THE HIGHER POPS ALONG THE I-10 CORRIDOR.
THUS IT POSSIBLE THAT THE SYSTEM BEGIN TO MOVE SLOWER THAN
FORECAST...DESPITE FAIRLY GOOD AGREEMENT IN RUN CONTINUITY AND
BETWEEN THE GFS AND EC MODELS. REMOVED POPS BY THURSDAY AS THE
UPPER DISTURBANCE MOVES NE AND AN UPPER RIDGE BUILDS IN.
04
&&
.PRELIMINARY POINT TEMPS/POPS...
ABILENE 56 80 54 79 58 / 20 10 10 5 5
SAN ANGELO 58 79 54 81 55 / 20 20 10 10 5
JUNCTION 58 77 53 81 53 / 20 20 10 10 5
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
25
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
344 AM CDT SAT MAY 11 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 343 AM CDT SAT MAY 11 2013
MAIN FORECAST CONCERNS ARE ON WINDS TODAY...AND IF FROST OR FREEZE
CONDITIONS CAN OCCUR TONIGHT.
CURRENTLY AS OF 08Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS
SHOWED STRONG RIDGING ALONG THE WEST COAST OF NORTH AMERICA AND A
SHARP/POTENT UPPER TROUGH DROPPING INTO NORTHERN MINNESOTA AND
NORTHWEST ONTARIO. A NARROW BAND OF SHOWERS CONTINUE ON RADAR
IMMEDIATELY AHEAD OF THE UPPER TROUGH...RESULTING FROM STRONG DPVA
AS WELL AS LOW LEVEL FRONTOGENETIC FORCING BEHIND A COLD FRONT. THIS
COLD FRONT EXTENDED FROM CENTRAL LAKE SUPERIOR TO WINONA MN AND DES
MOINES IA. PLENTY OF DRY AIR EXISTS BOTH AHEAD AND BEHIND THE COLD
FRONT...NOTED BY 00Z SOUNDINGS FROM MPX AND BIS. THE 00Z INL
SOUNDING WAS MOST REPRESENTATIVE OF THE ENVIRONMENT WITH THE NARROW
BAND OF SHOWERS...REFLECTING HIGH CLOUD BASES AND SATURATION MAINLY
FROM 750-550MB. THE HIGH CLOUD BASES COMBINED WITH THE LACK OF
MOISTURE KEEPING RAINFALL AMOUNTS VERY LOW WITH THE BAND OF SHOWERS.
AS EXPECTED WITH A HIGHLY AMPLIFIED UPPER TROUGH...A STRONG PRESSURE
RISE OF ALMOST 2 MB /1 HR WAS PRESENT BEHIND THE FRONT. THIS
PRESSURE RISE HAS RESULTED IN GUSTS OF 25-35 KT IMMEDIATELY AFTER
THE FRONTAL PASSAGE. A TIGHT PRESSURE GRADIENT EXISTS TOO BEHIND THE
FRONT...AHEAD OF CANADIAN HIGH PRESSURE IN SASKATCHEWAN. THE
BLUSTERY NORTHWEST WINDS ARE BRINGING UNSEASONABLY COOL AIR
SOUTHEAST...WITH 850MB TEMPS AT 00Z OF -5C AT THE PAS MANITOBA.
THE POTENT UPPER TROUGH APPROACHING THE FORECAST AREA IS PROGGED TO
ENCOMPASS MUCH OF THE WESTERN GREAT LAKES REGION BY THIS
EVENING...THEN BEGIN A SLOW MARCH EAST. THIS UPPER TROUGH WILL LEAD
TO A VARIETY OF CONCERNS FOR THE SHORT TERM PERIOD.
1. WINDS. AFTER THE COLD FRONT PASSES THROUGH THE REST OF THE
FORECAST AREA EARLY THIS MORNING...A TIGHT PRESSURE GRADIENT IS
PROGGED TO REMAIN IN PLACE PRETTY MUCH THROUGH TONIGHT. THE SURFACE
HIGH SEEN IN SASKATCHEWAN STAYS OFF WELL TO THE WEST...DROPPING DOWN
INTO SOUTHWEST MN BY 12Z SUNDAY. DEEP MIXING COMBINED WITH COLD
ADVECTION...A UNIDIRECTIONAL NORTHWEST FLOW AND STRONG SUBSIDENCE
FROM THE UPPER TROUGH CROSSING WILL RESULT IN A WINDY DAY TODAY.
WINDS AT THE TOP OF THE MIXED LAYER...AROUND 775MB...ONLY TOP OUT
AROUND 40 KT. MIXING THIS DOWN RESULTS IN MAX GUSTS IN THE 30-35 KT
RANGE...BELOW ADVISORY CRITERIA. WINDS ARE LIKELY TO DIMINISH THIS
EVENING WITH LOSS OF DAYTIME HEATING...BUT THERE IS NO CHANCE TO
DECOUPLE TONIGHT.
2. TEMPERATURES. 850MB TEMPS ARE PROGGED TO COOL TO AROUND -2C BY
18Z...OR 1.5-2 STANDARD DEVIATIONS BELOW NORMAL. AS MENTIONED IN THE
WINDS...THE STRONG MAY SUN WILL EASILY ALLOW MIXING UP TO 850MB AND
BEYOND...WHICH YIELDS HIGHS MAINLY IN THE LOW TO MID 50S. COLD
ADVECTION CONTINUES INTO TONIGHT AS 850MB TEMPS PLUNGE TO -4 TO -6C.
THE QUESTION IS IF THE WINDS MAY KEEP THE BOUNDARY LAYER MIXED
ENOUGH TO PREVENT TEMPERATURES FROM FALLING MUCH BELOW FREEZING. THE
11.00Z REGIONAL CANADIAN...ECMWF AND HIRES ARW KEEPS TEMPERATURES AT
OR ABOVE FREEZING ACROSS THE FORECAST AREA...WHEREAS THE 11.00Z NAM
HAS READINGS MORE IN THE 25 TO 30 RANGE. MOS GUIDANCE AND THE 11.00Z
GFS SPLIT THE DIFFERENCE AND KEEPS THE COLDEST TEMPERATURES OVER
CENTRAL WISCONSIN. TYPICALLY THE REGIONAL CANADIAN IS COLD FOR
LOWS...SO IT IS SURPRISING TO SEE IT BEING ONE OF THE WARMER MODELS.
GIVEN THE WIND...HAVE LEANED MORE TOWARDS THE 11.00Z GFS/HIRES ARW
AND REGIONAL CANADIAN IDEA. UPSTREAM OVER NORTH DAKOTA...
TEMPERATURES ARE STILL MOSTLY ABOVE FREEZING AS WELL AS OF 08Z.
3. FROST/FREEZE TONIGHT. VERY TRICKY AS NOTED BY THE TEMPERATURE
DISCUSSION ABOVE. WITH THE WIND AND DRY AIR ADVECTION TAKING PLACE
THROUGH TONIGHT...SEEMS HARD TO GET MUCH FROST DEVELOPMENT UNLESS
YOU ARE IN A REALLY SHELTERED LOCATION FROM THE NORTHWEST WIND.
RELATIVE HUMIDITIES LOOK TO STRUGGLE TO RISE TO 75 PERCENT. IN
ADDITION...WITH THE CONCERN ABOUT TEMPERATURES NOT FALLING BELOW
FREEZING...MAY NOT SEE FREEZE CONDITIONS EXCEPT PERHAPS IN TAYLOR
COUNTY. EVEN IF WE SEE FREEZE CONDITIONS...THEY MAY ONLY LAST AN
HOUR. THUS...HAVE NOT ISSUED ANY FROST/FREEZE HEADLINES FOR TONIGHT.
4. PRECIPITATION. ONGOING SHOWERS SHOULD PUSH SOUTHEAST OF THE AREA
BY 12Z THIS MORNING. UPSTREAM...THERE IS A CLUSTER OF CLOUDS ALONG
WITH A FEW SHOWERS AROUND THE GRAND FORKS AND FARGO AREAS OF NORTH
DAKOTA. THESE ARE ASSOCIATED WITH A SHORTWAVE WITHIN THE TROUGH.
GOOD MODEL AGREEMENT EXISTS OF THE SHORTWAVE AND CLOUDS DROPPING
THROUGH SOUTHERN MN AND NORTHERN IA TODAY. HAVE INCLUDED A FEW
SPRINKLES AS WELL AS THERE IS CONCERN THE SHOWERS MAY DRY UP SOME AS
HRRR RUNS SUGGEST. A FEW OTHER DIURNALLY DRIVEN SHOWERS/SPRINKLES
ASSOCIATED WITH THE COLD POOL MAY FORM TOO ACROSS TAYLOR/CLARK
COUNTIES.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 343 AM CDT SAT MAY 11 2013
SUNDAY THROUGH MONDAY NIGHT...THE UPPER RIDGE THAT HAS BEEN BUILDING
UP ALONG THE WEST COAT OF THE U.S. IS PROGGED BY ALL MODELS TO GET
PUSHED EAST DURING THIS PERIOD...IN RESPONSE TO A STRONG SHORTWAVE
COMING INTO THE PACIFIC NORTHWEST LATE MONDAY. THIS UPPER RIDGE WILL
HELP TO KEEP THIS PERIOD OF UNSEASONABLY COOL AIR BRIEF. BY LATE
SUNDAY NIGHT...WESTERN PORTIONS OF THE FORECAST AREA SHOULD START
GETTING INTO THE WARM ADVECTION SETUP. UNTIL THEN...MAIN CONCERN IS
FROST/FREEZE SUNDAY NIGHT. MODELS PROG THE SURFACE CANADIAN HIGH
PRESSURE RIDGE TO BE CENTERED OVER THE ENTIRE FORECAST AREA AT 06Z
MONDAY...LEADING TO CLEAR SKIES AND LIGHT WINDS. GIVEN A COOL SUNDAY
TO BEGIN WITH...SITUATION SHOULD BE VERY FAVORABLE FOR FROST/FREEZE
CONDITIONS ACROSS MUCH OF THE FORECAST AREA...ESPECIALLY OVER
WISCONSIN. LEANED TOWARDS THE COOLER SIDE OF GUIDANCE FOR LOWS...
RESULTING IN THE NEED FOR A FREEZE WATCH FOR COUNTIES ALONG AND
NORTHEAST OF I-94. THE WARM ADVECTION MONDAY INTO MONDAY NIGHT IS
INTERESTING AS 850MB TEMPS CLIMB ABOUT 12C FROM 12Z MONDAY TO 12Z
TUESDAY. GOOD MODEL AGREEMENT EXISTS THAT AN AREA OF MID AND HIGH
CLOUDS WILL DEVELOP IN RESPONSE TO THIS WARM ADVECTION. ISENTROPIC
LIFT FIELDS ON THE 295 AND 300K SURFACE SHOW AN AREA OF LIFT
OCCURRING WITHIN THESE CLOUDS...MARCHING EAST WITH TIME. THE 11.00Z
GFS/ECMWF AND 11.03Z SREF ALL DEVELOP PRECIPITATION...WHILE THE
11.00Z NAM IS DRY. THE NAM DOES NOT DEVELOP PRECIPITATION BECAUSE OF
DRY LOW LEVELS ABSORBING THE RAIN...WHICH THE NAM TENDS TO OVERDO.
THUS...HAVE KEPT AND RAISED SLIGHTLY THE PRECIPITATION CHANCES FOR
MONDAY AFTERNOON AND EVENING. DID TAKE OUT THE THUNDER...THOUGH...AS
NO INSTABILITY EXISTS.
FOR THE REST OF THE WEEK...
FOCUS REMAINS ON HIGH TEMPERATURES ON TUESDAY. 11.00Z CANADIAN AND
ECMWF HAVE WENT BACK AND NOW SHOW A SURFACE WARM FRONT PROGRESSING
THROUGH THE AREA QUICKER...WHICH ALLOWS WARMER AIR TO PUSH INTO THE
AREA DURING THE DAY. THE 11.00Z GFS HAS STAYED PERSISTENT. ALL
MODELS NOW SHOW 850MB TEMPS CLIMBING TO 18C OVER CENTRAL WISCONSIN
TO 24C NEAR I-35 BY 00Z...WHICH ARE 2.5 STANDARD DEVIATIONS ABOVE
NORMAL. ONCE YOU GET TO 2.5...CONCERN INCREASES OF REACHING RECORDS.
PROBLEM IS MOST MODEL GUIDANCE HAS TOO MUCH MOISTURE IN THE BOUNDARY
LAYER. THE SCENARIO IS THE GULF OF MEXICO IS CUT OFF BY THE CURRENT
CANADIAN HIGH DROPPING DOWN TO THE GULF COAST...AND CROPS THAT ARE
BEHIND SCHEDULE DUE TO THE COOL SPRING. MODELS ARE TRYING TO GET THE
MOISTURE FROM EVAPOTRANSPORATION. WITH TOO MUCH MOISTURE IN THE
BOUNDARY LAYER...TEMPERATURES CANNOT RISE ENOUGH FROM MIXING.
THUS...HAVE STAYED PRETTY CLOSE TO THE PREVIOUS FORECAST AND BOOSTED
READINGS A FEW DEGREES WEST OF THE MISSISSIPPI RIVER TO ACCOUNT FOR
THE GROWING CONSENSUS ON THE WARM AIR TIMING. TEMPERATURES MAY STILL
NEED TO BE RAISED FURTHER.
A COLD FRONT ACCOMPANYING THAT TROUGH COMING INTO THE PACIFIC
NORTHWEST MONDAY IS SLATED TO COME THROUGH THE FORECAST AREA TUESDAY
NIGHT AND WEDNESDAY. FOLLOWED A CONSENSUS BLEND AND HAVE JUST LOW
CHANCES FOR SHOWERS/STORMS AS THE FRONT MOVES THROUGH. BEYOND
WEDNESDAY...THE FORECAST GETS MUDDLED WITH THE 11.00Z ECMWF/CANADIAN
SUGGESTING MORE OF A ZONAL TO SLIGHT UPPER RIDGING PATTERN IN PLACE
AS TROUGHING REFORMS IN THE PACIFIC NORTHWEST. MEANWHILE...THE
11.00Z GFS/GFS ENSEMBLES DEPICT TROUGHING TO FORM AND LINGER AROUND
THE FORECAST AREA. BOTH SITUATIONS SUGGEST A TREND TOWARDS
DRIER...AND THEREFORE THE CHANCES OF PRECIPITATION HAVE BEEN LOWERED
SOME. COULD SEE FINE TUNING TAKING PLACE TO DRY OUT PORTIONS OF THE
WEDNESDAY NIGHT THROUGH FRIDAY PERIOD. OTHERWISE...TEMPERATURES LOOK
COOLER BUT SHOULD STILL STAY NEAR OR ABOVE NORMAL WITH A MOSTLY
PACIFIC FLOW OF AIR.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1100 PM CDT FRI MAY 10 2013
A COLD FRONT WILL SWEEP NORTHWEST TO SOUTHEAST ACROSS THE REGION
EARLY THIS MORNING...LIKELY THROUGH KRST AROUND 08Z AND KLSE
AROUND 10Z. A THIN BAND OF CLOUDS IS CURRENTLY ASSOCIATED WITH THE
FRONT...PER LATEST SATELLITE IMAGERY...WITH SFC OBS PLACING THESE
AROUND 10 KFT. SOME SCT/ISOLD PCPN POST THE FRONT PER 88-D RADAR
IMAGERY...AND MESO MODELS FAVOR BRINGING A SCT-BKN BAND OF -SHRA
ACROSS THE AREA WITH THE PASSAGE OF THE FRONT. THE PCPN THREAT LOOKS
CONFINED TO ABOUT 2 TO 3 HOURS. SFC OBS NOT INDICATING ANY CIGS
LOWER THAN THE MID LEVEL AC...AND MESO MODELS AND BUFKIT SOUNDINGS
ARE NOT TOO EXCITED ABOUT LOW CIGS NOW EITHER. HAVE REMOVED THESE
FROM TAFS AS A RESULT. THE GFS/NAM INDICATE A SWATH OF LOW RH THAT
COULD MANIFEST INTO A FEW HOUR PERIOD OF VFR CIGS LATE MORNING.
ALSO...BUFKIT SOUNDINGS SUGGEST SOME SCT AFTERNOON CU WHICH WOULD
RESULT IN A SHORT PERIOD OF BKN. AGAIN THOUGH...LOOKS TO BE VFR AT
THIS TIME.
WINDS WILL BE ON THE INCREASE POST THE FRONT AS THE SFC PRESSURE
GRADIENT TIGHTENS AND THE WINDS START TO MIX UPWARDS OF 9 KFT. IT
WILL LIKELY BE GUSTY BEFORE 12Z SAT...WITH WINDY/GUSTY CONDITIONS
PERSISTING THROUGH THE DAYLIGHT HOURS. GUSTS AROUND 30 KTS LOOK
REASONABLE FOR KRST...A BIT LESS AT KLSE.
&&
.FIRE WEATHER...
ISSUED AT 343 AM CDT SAT MAY 11 2013
BREEZY NORTHWEST WINDS ARE EXPECTED THIS WEEKEND AHEAD OF A
STRONG AREA OF CANADIAN HIGH PRESSURE OVER SASKATCHEWAN DROPPING
SOUTHEASTWARD. THESE NORTHWEST WINDS ARE GOING TO USHER IN AN
UNSEASONABLY COOL AND DRY AIRMASS INTO THE FORECAST AREA. DEEP
MIXING RESULTING FROM THE STRONG MAY SUN SHOULD ALLOW DEWPOINTS TO
DROP INTO THE MID TEENS TO MID 20S DURING THE AFTERNOON...WHICH
WITH HIGH TEMPERATURES IN THE LOW TO MID 50S...RELATIVE HUMIDITIES
WILL DROP TO 20 TO 30 PERCENT. PRECLUDING A RED FLAG WARNING AT
THIS TIME IS A COMBINATIN OF THE COOL TEMPERATURES...THE RECENT
SOAKING RAIN ON THURSDAY RESULTING IN WETTER FUELS...AND GREEN
UP THAT REALLY TOOK OFF THIS WEEK.
HEADING INTO EARLY NEXT WEEK...FOCUS REMAINS ON TUESDAY AS
SOUTHEAST MINNESOTA AND NORTHEAST IOWA BECOME POSITIONED IN A VERY
WARM ENVIRONMENT. TEMPERATURES LOOK TO CLIMB INTO THE MID TO UPPER
80S...AND PERHAPS COULD EVEN CLIMB INTO THE LOW 90S. DEWPOINT
FORECASTS ARE A LITTLE DIFFICULT AT THIS TIME WITH MOST MODELS
APPEARING TO OVERDO THEM...BUT RELATIVE HUMIDITIES SHOULD DROP AT
LEAST TO 35 TO 40 PERCENT. IT IS POSSIBLE THESE COULD END UP LOWER
AS CERTAINTY ON DEWPOINTS INCREASES. WINDS LOOK MARGINAL RIGHT
NOW FOR RED FLAG CONDITIONS. NEEDLESS TO SAY...SOMETHING TO KEEP
AN EYE ON OVER THE NEXT FEW DAYS.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...FREEZE WATCH FROM LATE SUNDAY NIGHT THROUGH MONDAY MORNING FOR
WIZ017-029-034-042>044.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION.....04
FIRE WEATHER...AJ
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
253 AM MDT SAT MAY 11 2013
.SHORT TERM...(TODAY THROUGH SUNDAY NIGHT)
ISSUED AT 116 AM MDT SAT MAY 11 2013
FORECAST CHALLENGES DEAL WITH PRECIP CHANCES TODAY...FOLLOWED BY
TEMPERATURES FOR SUNDAY.
CURRENTLY...COLD FRONT HAS MADE IT THROUGH MUCH OF SOUTHEAST
WYOMING EARLY THIS MORNING. WE HAVE NORTH TO NORTHEAST WINDS FOR
JUST ABOUT EVERYWHERE...INCLUDING RAWLINS. 1034MB SURFACE HIGH
OVER ALBERTA CANADA. SEEING A FEW SHOWERS ON RADAR...BUT THEY ARE
QUICKLY MOVING SOUTH INTO NORTHERN COLORADO BEHIND THE FRONT.
FRONT WILL BEGIN TO MOVE BACK TO THE NORTHEAST LATER THIS MORNING
AND SHOULD BE LAYING ALONG THE LARAMIE RANGE DURING PEAK HEATING
THIS AFTERNOON. NAM CAPE VALUES AROUND 400J/KG AND LIFTED INDICES
DOWN TO -2C. ALL THREE MODELS...NAM...GFS AND ECMWF TARGETING THE
SOUTHERN LARAMIE RANGE AS THE BEST CHANCES FOR PRECIP THIS
AFTERNOON AND I RAISED POPS A LITTLE MORE FOR THIS
AREA...INCLUDING CHEYENNE. NORTHERN PANHANDLE...CONVERSE AND
NIOBRARA COUNTIES COULD STAY DRY THROUGH THE DAY.
HEAT UP BEGINS TONIGHT INTO SUNDAY AS 700MB TEMPERATURES RISE IN
RESPONSE TO A BUILDING RIDGE ALOFT. 700MB TEMPERATURES THIS
AFTERNOON OF 0C OVER THE PANHANDLE AND +6C OVER CARBON COUNTY RISE
TO +6C AND +10C RESPECTIVELY BY SUNDAY AFTERNOON. SHOULD SEE
WIDESPREAD 70S ACROSS SOUTHEAST WYOMING AND LOW 80S IN THE
PANHANDLE SUNDAY AFTERNOON.
.LONG TERM...(MONDAY THROUGH FRIDAY NIGHT)
ISSUED AT 226 AM MDT SAT MAY 11 2013
MODELS IN GENERALLY GOOD AGREEMENT THROUGH NEXT WEEK...SHOWING
WARM TEMPERATURES AND DRY CONDITIONS MOST OF THE TIME ACROSS
SOUTHEAST WYOMING AND WESTERN NEBRASKA. UPPER LEVEL RIDGE AXIS
WILL SHIFT FROM UTAH ON SUNDAY INTO THE GREAT PLAINS BY MONDAY
NIGHT. 700MB TEMPERATURES INCREASE BETWEEN 10C TO 13C BY MONDAY
AND TUESDAY...WHICH TRANSLATES TO HIGH TEMPERATURES AT THE SURFACE
IN THE 70S AND 80S...WITH POSSIBLY A FEW LOW 90S ACROSS THE LOWEST
ELEVATIONS OF WESTERN NEBRASKA. A PACIFIC STORM SYSTEM WILL PUSH
EASTWARD ACROSS MONTANA ON TUESDAY...WELL NORTH OF WYOMING. A COLD
FRONT WILL SLOWLY PUSH SOUTH ACROSS THE FORECAST AREA TUESDAY
NIGHT RESULTING IN COOLER TEMPERATURES ON WEDNESDAY...BUT TEMPS
WILL REMAIN NEAR NORMAL FOR THIS TIME OF THE YEAR. BREEZY OR WINDY
CONDITIONS ARE LIKELY ON TUESDAY WITH SOME OF THE WARMEST
TEMPERATURES SO FAR THIS SPRING. TEMPERATURES WILL INCREASE BACK
INTO THE 70S AND LOW 80S BY THE END OF THE WEEK. THE MAIN FORECAST
CHALLENGE IN THE LONG TERM IS PRECIPITATION CHANCES...AS MODELS
INDICATE A SLIGHT CHANCE OF SHOWERS AND TSTORMS EACH DAY FROM
WEDNESDAY THROUGH FRIDAY. THIS WILL DEPEND ON THE POSITION OF A
WEAK COOL FRONT AND MOISTURE GRADIENT WHICH MODELS SHOW ALIGNING
ITSELF ALONG THE LARAMIE RANGE DURING THE DAY...AND RETREATING
EASTWARD ACROSS THE PLAINS AT NIGHT. KEPT A 15 TO 20 PERCENT
CHANCE OF SHOWERS AND TSTORMS ALONG AND EAST OF THE LARAMIE RANGE
EACH DAY. MODEL SOUNDINGS INDICATE ENOUGH CAPE...MOISTURE...AND
INSTABILITY TO SUPPORT ISOLATED COVERAGE OF SHOWERS/TSTORMS
WEDNESDAY AND FRIDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1057 PM MDT FRI MAY 10 2013
COLD FRONT LOOKS TO HAVE MOVED THROUGH THE CHEYENNE AREA WITH
NORTHEASTERLY WINDS IN PLACE NOW. SOME INDICATIONS THAT WE WILL
SEE FOG AT KCYS AND KLAR. HRRR NOT REALLY HITTING THESE TWO
AIRPORTS VERY HARD...SO CONFIDENCE NOT TOO HIGH ON THIS HAPPENING.
IF IT DOES FORM...IT WILL BE RIGHT AROUND SUNRISE AND LAST FOR A
COUPLE HOURS. WILL CONTINUE TO MONITOR.
&&
.FIRE WEATHER...
ISSUED AT 116 AM MDT SAT MAY 11 2013
ONE LAST DAY OF SHOWERS AND THUNDERSTORMS TODAY AS A COLD FRONT
LAYS UP AGAINST THE LARAMIE RANGE. BEST CHANCES FOR WETTING RAINS
WILL BE RIGHT ALONG THE LARAMIE RANGE. CONDITIONS THEN BEGIN TO
WARM AND DRY OUT AS THE FRONT MOVES EAST. MONDAY AND TUESDAY LOOK
TO BE QUITE WARM AND BREEZY...WITH AFTERNOON HUMIDITIES FALLING
INTO THE LOW TO MID TEENS. MOST AREAS ARE IN GREEN UP...BUT FOR
THOSE THAT HAVE NOT...WE COULD BE LOOKING AT RED FLAG CONDITIONS
AS WINDS WILL BE QUITE STRONG. THIS WILL BE ESPECIALLY TRUE FOR
LATE MONDAY AFTERNOON THROUGH TUESDAY. AFTERNOON HUMIDITIES MONDAY
WILL FALL INTO THE LOW TEENS WITH POOR OVERNIGHT RECOVERIES MONDAY
NIGHT.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&
$$
SHORT TERM...CLAYCOMB
LONG TERM...TJT
AVIATION...CLAYCOMB
FIRE WEATHER...CLAYCOMB
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
1100 PM MDT FRI MAY 10 2013
.UPDATE...
ISSUED AT 849 PM MDT FRI MAY 10 2013
FORECAST MOSTLY ON TRACK THIS EVENING. A FEW ISOLATED SHOWERS
ACROSS THE AREA AT THIS TIME. A FEW STRONGER GUSTS HAVE BEEN
REPORTED WITH THIS SHOWER ACTIVITY. TORRINGTON AIRPORT REPORTED A
GUST OF 48 MPH AT 805 PM. COULD SEE LOCALIZED GUSTS 40 TO 50 MPH
WITH A FEW SHOWERS YET THIS EVENING BUT WITH THE WITH THE LOSS OF
DAYTIME HEATING...SHOULD SEE GUSTS DECREASING IN STRENGTH. MAY
NEED TO TWEAK TEMPERATURES A BIT FOR THIS EVENING AS TEMPERATURES
ARE DROPPING OFF RATHER QUICKLY UNDER A DRY AIR-MASS. ALSO MAY KNOCK
A FEW DEGREES OFF THE LOWS FOR TONIGHT BUT OTHERWISE EVERYTHING
LOOKING GOOD.
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY AFTERNOON)
ISSUED AT 619 PM MDT FRI MAY 11 2013
COLD FRONT IS MOVING SOUTH THROUGH THE NORTHERN TIER OF COUNTIES AT
TAF ISSUANCE...WITH SCATTERED RAIN SHOWERS MOVING WITH THE
FRONT. THIS ACTIVITY WILL MOVE SOUTH THIS EVENING ACROSS THE
REMAINING AREAS WITH WINDS OUT OF THE NORTH TO NORTHEAST BEHIND
THE FRONT. LOWERING CIGS AND VSBYS ARE EXPECTED AT KLAR AND KCYS
IN MOIST UPSLOPE FLOW LATE TONIGHT. WINDS WILL SHIFT TO THE SOUTH
ACROSS THE EASTERN PLAINS...AND NORTHWEST WEST OF THE LARAMIE
RANGE SATURDAY MORNING. CHANCES FOR SHOWERS AND THUNDERSTORMS WILL
INCREASE IN THE AFTERNOON ALONG AND WEST OF THE LARAMIE RANGE WITH
THE FOCUS ALONG THE HIGHER TERRAIN.
&&
.SHORT TERM...(TONIGHT THROUGH SATURDAY NIGHT)
ISSUED AT 345 PM MDT FRI MAY 10 2013
A CANADIAN COLD FRONT CONTINUES TO MOVE SOUTH INTO EAST CENTRAL WY
THIS AFTN. AFTN SFC OBS SHOWED THIS FRONT DRAPED FROM WEST TO EAST
FROM NORTHEAST WY INTO WEST CENTRAL SOUTH DAKOTA. LLVL CONVERGENCE
ALONG THIS BOUNDARY...COMBINED WITH DIURNAL INSTABILITY AND MODEST
MIDLVL MOISTURE HAS CONTRIBUTED TO THE DEVELOPMENT OF ISOLATED TO
WIDELY SCATTERED SHOWERS AND TSTMS ACROSS MUCH OF THE AREA. RADAR
HAS NOT INDICATED ANYTHING PARTICULARLY STRONG...AND THIS SHOULD
BE THE CASE THROUGH EARLY EVE WITH SBCAPES GENERALLY LESS THAN
250 J/KG PER SPC MESOSCALE ANALYSIS. MAIN CONVECTIVE HAZARD SHOULD
BE GUSTY DOWNBURST WINDS WITH AN INVERTED-V LOOK TO FCST SOUNDINGS.
THE PREVIOUS FCST LOOKS ON TRACK WITH THE IDEA THAT BETTER PCPN
CHANCES WILL COME DURING THE LATE AFTN AND EARLY EVE. DRY AIR ALOFT
HAS BEEN OVERHEAD FOR MOST OF THE DAY...BUT INCREASING MIDLVL
MOISTURE IN THE POST-FRONTAL AIR MASS SHOULD SUPPORT BETTER PCPN
COVERAGE BY LATE AFTN. STILL LOOKS LIKE ACTIVITY WILL DECREASE AFTER
DARK WITH THE LOSS OF AFTERNOON HEATING AND AS THE FRONT CONTINUES
TO SAG SOUTHWARD INTO NORTHERN CO.
BEST CHANCE FOR CONVECTION THIS PERIOD WILL BE SAT AFTN AND EVE AS
THE SFC BOUNDARY HANGS UP ALONG THE FRONT RANGE. MODELS SHOW STEEP
MIDLVL LAPSE RATES BETWEEN 7 AND 8 DEG C/KM CONTRIBUTING TO A FEW
HUNDRED J/KG OF SBCAPE BY MID AFTN. ENVIRONMENT SHOULD BE PRIME
FOR SHOWER AND THUNDERSTORM ACTIVITY ONCE AGAIN AS LLVL CONVERGENCE
BECOMES ENHANCED ALONG THE LARAMIE RANGE. A DRY BOUNDARY LAYER
WOULD SUGGEST HIGH BASED STORMS WITH GUSTY...SUB-SEVERE WINDS THE
MAIN HAZARD. THERMAL FIELDS REBOUND QUICKLY FOLLOWING THE COLD
FRONTAL PASSAGE AS UPPER-LEVEL RIDGING BUILDS INTO THE AREA. GFS
SHOWS 700 MILLIBAR TEMPS INCREASING TO BETWEEN 3C AND 6C AND 1000-
500 MILLIBAR THICKNESS VALUES AROUND 564 DM. AS SUCH...AFTN HIGHS
SHOULD BE SIMILAR TO FRIDAY WITH MID 60S LIKELY.
.LONG TERM...(SUNDAY THROUGH THURSDAY)
ISSUED AT 345 PM MDT FRI MAY 10 2013
WARM...DRY...AND INCREASINGLY BREEZY CONDITIONS WILL BE THE
WEATHER STORY FROM SUNDAY INTO EARLY NEXT WEEK. UPPER LEVEL RIDGE
AXIS WILL SHIFT FROM UTAH ON SUNDAY INTO THE PLAINS BY MONDAY
NIGHT. 700MB TEMPS INCREASE TO AROUND 8C BY SUNDAY AND THEN BECOME
11-13C BY MONDAY AND TUESDAY. AS FLOW ALOFT BECOMES MORE
SOUTHWESTERLY AND PRESSURE FALLS OCCUR OVER THE PLAINS ON
MONDAY...THE REGION WILL SEE BREEZY CONDITIONS DEVELOP ESPECIALLY
OVER SOUTHEAST WY. CURRENTLY HAVE WIDESPREAD 80S AND EVEN A FEW 90
DEGREE READINGS IN THE NORTH PLATTE VALLEY EARLY NEXT WEEK.
SHORTWAVE PUSHES ACROSS MONTANA AND THEN INTO THE DAKOTAS ON
TUESDAY NIGHT. THIS WILL PUSH A WEAK COLD FRONT THROUGH THE CWA
DURING THE NIGHT WITH TEMPS ON WEDNESDAY AROUND 10-15 DEGREES
COOLER. LLVL THICKNESSES BEGIN TO RISE AGAIN ON THURSDAY FOR A
RETURN TO ABOVE NORMAL TEMPS. PRECIP CHANCES LOOK QUITE SLIM
THROUGH THE EXTENDED PERIOD WITH A DRY BOUNDARY LAYER AND WARM
MIDLEVEL TEMPS INHIBITING CONVECTION. CAN NOT RULE OUT A FEW HIGH
BASED STORMS EACH AFTN THAT MOSTLY PRODUCE VIRGA AND GUSTY WINDS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY EVENING)
ISSUED AT 1057 PM MDT FRI MAY 10 2013
COLD FRONT LOOKS TO HAVE MOVED THROUGH THE CHEYENNE AREA WITH
NORTHEASTERLY WINDS IN PLACE NOW. SOME INDICATIONS THAT WE WILL
SEE FOG AT KCYS AND KLAR. HRRR NOT REALLY HITTING THESE TWO
AIRPORTS VERY HARD...SO CONFIDENCE NOT TOO HIGH ON THIS HAPPENING.
IF IT DOES FORM...IT WILL BE RIGHT AROUND SUNRISE AND LAST FOR A
COUPLE HOURS. WILL CONTINUE TO MONITOR.
&&
.FIRE WEATHER...
ISSUED AT 345 PM MDT FRI MAY 10 2013
MOST OF THE AREA IS CURRENTLY GREENING UP DUE TO THE RECENT RAIN
AND SNOW IN THE PAST FEW WEEKS. THE TEMPERATURES WILL BEGIN TO
WARM BY SUNDAY INTO EARLY NEXT WEEK...WITH AN ASSOCIATED DECREASE
IN MINIMUM AFTERNOON HUMIDITIES. MOST OF THE LOWER ELEVATIONS WILL
SEE AFTERNOON HUMIDITIES IN THE 15-20 PERCENT RANGE BY MONDAY AND
TUESDAY. SOUTHWEST-TO-WEST WINDS WILL ALSO INCREASE BY EARLY NEXT
WEEK ESPECIALLY OVER SOUTHEAST WY. WILL HAVE TO MONITOR THE RED
FLAG POTENTIAL EARLY NEXT WEEK OVER THE PANHANDLE SINCE FUELS ARE
CURRENTLY LISTED AS CRITICAL OUT THERE.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&
$$
UPDATE...LIEBL
SHORT TERM...HAMMER
LONG TERM...FINCH
AVIATION...CLAYCOMB
FIRE WEATHER...FINCH
AREA FORECAST DISCUSSION
NWS TAUNTON MA
1011 AM EDT SAT MAY 11 2013
.SYNOPSIS...
SHOWERS AND SCATTERED THUNDERSTORMS AHEAD OF A COLD FRONT ARE
EXPECTED INTO TONIGHT. THE COLD FRONT WILL MOVE ACROSS THE REGION
LATE TONIGHT AND STALL SUNDAY BEFORE MOVING TO THE EAST SUNDAY
NIGHT. COOLER AND DRIER WEATHER WILL FOLLOW FOR EARLY NEXT WEEK.
EXPECT A RETURN TO A MORE UNSETTLED PATTERN FOR THE LATTER PART
OF NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
10 AM UPDATE...
A LITTLE BIT OF LOW TO MID LVL RIDGING EVIDENT AHEAD CONVECTIVE
COMPLEX OVER NJ/DE AND ERN PA. THIS HAS LEAD TO A LITTLE BIT OF A
BREAK IN THE -SHRA ACTIVITY ACROSS THE REGION THIS MORNING.
HOWEVER...AM NOTING SOME BREAKS IN THE SKIES IN VIS SATELLITE
IMAGES AND LOCAL WEB CAMS CONFIRM SUNSHINE BEGINNING TO SHOW
THROUGH. MESOSCALE MODELS STILL SUPPORT MOST OF THE INSTABILITY
IS WELL S OF THE REGION...AND DUE E OF THE CONVECTIVE COMPLEX.
HOWEVER...WILL NEED TO WATCH THESE BREAKS...ESPECIALLY THOSE OVER
S CENTRAL NY AND NE PA...WHICH MAY MOVE OVER DURING PEAK HEATING.
EVEN IF STORMS FAIL TO ORGANIZE...AND THIS REMAINS AN IF...DECENT
LLJ STILL APPARENT WITH 40-50 KT OFF THE DECK COULD SUPPORT GUSTY
WINDS WITH ANY -SHRA. NOT SEEING THE INVERTED V SOUNDING...BUT
DEWPOINT DEPRESSIONS CONTINUE TO INCREASE SO MAY SEE SOME OF THIS
ENERGY REACH THE SFC WITH AFTERNOON HEAVIER -SHRA. THIS WILL HAVE
TO BE WATCHED. ADJUSTED POPS/WX/SKIES TOWARD LATEST HRRR AND
RAP...WHICH SUPPORT THE THINKING FOR FURTHER DEVELOPMENT THIS
AFTERNOON.
PREVIOUS DISCUSSION...
AS THE LOW LEVEL JET MOVES EWD...DEEP LAYER MOISTURE AND LIFT
WILL RESULT IN NUMEROUS SHOWERS MOVING ACROSS THE REGION
TODAY...ALTHOUGH IT APPEARS THE SHOWERS WILL BE CONCENTRATED IN
THE WEST AND BECOME MORE FOCUSED IN SE NEW ENG LATE TODAY. THERE
IS ENOUGH ELEVATED INSTABILITY TO SUPPORT ISOLD TO SCT
THUNDERSTORMS TODAY. OF MORE CONCERN IS THE POTENTIAL FOR SFC
BASED INSTABILITY THIS AFTERNOON AHEAD OF THE COLD FRONT AS DEEP
LAYER SHEAR IS RATHER STRONG. MODELS SUGGEST MARGINAL SBCAPES LESS
THAN 1000 J/KG DEVELOPING ACROSS W NEW ENG. IT APPEARS THAT THE
SHOWERS AND CLOUD COVER WILL LIMIT INSTABILITY AND MID LEVEL LAPSE
RATES ARE ALSO UNFAVORABLE. SO WHILE WE CANT RULE OUT A
THUNDERSTORM WITH GUSTY WINDS IN THE WEST...THE MAIN THREAT WILL
BE LOCALLY HEAVY RAINFALL IN HIGH PWAT AIRMASS.
USED A BLEND OF MOS GUIDANCE FOR MAX TEMPS TODAY...GENERALLY
UPPER 60S TO LOWER 70S. IT WILL ALSO BE SOMEWHAT HUMID WITH
DEWPOINTS CLIMBING TO 60+. BREEZY SW WINDS DEVELOPING IN THE
COASTAL PLAIN THIS AFTERNOON.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SUNDAY/...
TONIGHT...
POSITION OF THE LOW LEVEL JET SUGGESTS SHOWERS AND ISOLD TSTMS
WILL BE WIDESPREAD ACROSS SE NEW ENG THIS EVENING WITH LESS
COVERAGE FURTHER WEST...THEN SHOWERS MOVE TO THE EAST OVERNIGHT
AS THE JET MOVES OFFSHORE. COLD FRONT MOVES INTO SNE OVERNIGHT
WITH DRIER MOVING IN BEHIND IT...MAINLY FOR WESTERN NEW ENG.
SUNDAY...
SFC FRONT STALLS ACROSS SNE DURING THE DAY. WITH MID LEVEL TROF
HANGING BACK TO THE WEST AND SHORTWAVE ENERGY ROTATING INTO NEW
ENG...THERE IS A POTENTIAL FOR RENEWED SHOWERS AND ISOLD
TSTMS...ESPECIALLY IN EASTERN NEW ENG WHERE BEST LOW LEVEL
CONVERGENCE WILL BE LOCATED. GUIDANCE INDICATES INSTABILITY WILL
BE LIMITED SO COVERAGE OF ANY TSTMS SHOULD BE ISOLATED. MAX TEMPS
SHOULD REACH UPPER 60S TO LOWER 70S...WARMEST IN RI AND SE MA.
COOLER AIRMASS NW ZONES IN POST FRONTAL AIRMASS.
&&
.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
HIGHLIGHTS...
* COOLER AND DRIER WEATHER MONDAY AND TUESDAY
* MORE UNSETTLED WEATHER RETURNS MIDDLE OF NEXT WEEK
THE MODELS EXHIBIT GOOD AGREEMENT ON SYNOPTIC SCALE FEATURES
THROUGHOUT MUCH OF THE FORECAST PERIOD. HIGH PRESSURE BUILDS INTO
SOUTHERN NEW ENGLAND MONDAY AND TUESDAY AS LOW PRESSURE MOVES UP
THE COAST...PASSING EAST OF SOUTHERN NEW ENGLAND TUESDAY. SHOWERS
ARE POSSIBLE WEDNESDAY AHEAD OF A COLD FRONT THAT WILL MOVE
THROUGH THE AREA THURSDAY. THERE ARE SOME DIFFERENCES BETWEEN THE
GFS AND ECMWF TOWARDS THE END OF NEXT WEEK. THE EURO IS SLOWER
MOVING AN EAST COAST RIDGE OUT TO SEA WHILE THE GFS MOVES IT OUT
FAIRLY QUICKLY ALLOWING ANOTHER LOW PRESSURE SYSTEM TO AFFECT THE
AREA FRIDAY. GENERALLY WENT WITH A BLEND OF GUIDANCE FOR THE
FORECAST.
SUNDAY NIGHT THROUGH WEDNESDAY...HIGH PRESSURE STARTS TO BUILD
INTO THE EAST MONDAY AND TUESDAY AS LOW PRESSURE MOVES UP THE
COAST WELL EAST OF THE AREA INTO THE MARITIMES. THE HIGH PRESSURE
WILL MOVE OFFSHORE WEDNESDAY. MUCH OF THIS PERIOD IS EXPECTED TO
BE DRY... THOUGH A COLD CORE ALOFT WILL STEEPEN LAPSE RATES ENOUGH
THAT TOGETHER WITH DAYTIME HEATING COULD PRODUCE SOME DIURNAL
SHOWERS. BELOW AVERAGE TEMPERATURES ARE EXPECTED WITH MOSTLY SUNNY
SKIES. THE BIG IMPACT HERE WILL BE OVERNIGHT...WITH TEMPERATURES
EXPECTED TO DROP INTO THE 30S. WILL KEEP THE FROST WORDING IN THE
WEATHER GRIDS. MONDAY NIGHT LOOKS TO BE THE CHILLIEST NIGHT WITH
TEMPERATURES POSSIBLY DOWN TO FREEZING ACROSS PORTIONS OF THE
NORTHWESTERN ZONES.
THURSDAY AND FRIDAY...PLENTY OF UNCERTAINTY HERE WITH DIFFERENT
SYNOPTIC PATTERNS IN THE MODELS. THE ECMWF KEEPS THE UPPER LEVEL
RIDGE OVER THE EAST COAST A BIT LONGER THAN THE GFS. REGARDLESS...
THIS PERIOD LOOKS TO BE A BIT MORE UNSETTLED THAN EARLIER IN THE
WEEK. IT DOES LOOK AS THOUGH TEMPERATURES WILL RETURN TO NORMAL
OR POSSIBLY ABOVE NORMAL LEVELS THROUGH THE END OF THE WEEK.
&&
.AVIATION /14Z SATURDAY THROUGH WEDNESDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
OVERVIEW...LOW CONFIDENCE ON CIG/VSBYS THROUGH TONIGHT.
TODAY...LINGERING IFR THIS MORNING...OTHERWISE MVFR CONDITIONS
EXPECTED AS SHOWERS MOVE ACROSS THE REGION FROM WEST TO EAST
TODAY. ISOLD TO SCT TSTMS POSSIBLE...ESPECIALLY WEST WITH LOCALLY
HEAVY RAIN AND GUSTY WINDS. SW WIND GUSTS TO 25 KT DEVELOPING THIS
AFTERNOON IN THE COASTAL PLAIN.
TONIGHT...SHOWERS AND ISOLD TSTMS WILL BECOME FOCUSED ACROSS SE
NEW ENG THIS EVENING. OTHERWISE...EXPECT IFR CONDITIONS TO
DEVELOP ACROSS MUCH OF THE REGION AS STRATUS AND PATCHY FOG
DEVELOPS.
SUN...CONDITIONS SHOULD IMPROVE TO VFR. BUT A FEW SHOWERS OR A
THUNDERSTORM POSSIBLE WHICH MAY BRING BRIEF MVFR ESPECIALLY E NEW
ENG.
KBOS TERMINAL...OVERALL LOW CONFIDENCE ON CIG FORECAST. WE HAVE
MAINLY VFR CIGS TODAY...LOWERING TO IFR TONIGHT. BUT LOWER CIGS
COULD DEVELOP EARLIER.
KBDL TERMINAL...MODERATE CONFIDENCE IN TAF.
OUTLOOK...SUNDAY NIGHT THROUGH WEDNESDAY...
SUNDAY NIGHT THROUGH WEDNESDAY...MODERATE CONFIDENCE. MAINLY VFR.
COULD SEE MVFR/IFR CONDITIONS IN DIURNAL SHOWERS EACH DAY.
&&
.MARINE...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
FORECAST CONFIDENCE HIGH THROUGH SUNDAY.
TODAY...INCREASING SW WINDS EXPECTED WITH GUSTS TO 25 KT
DEVELOPING AS THE LOW LEVEL JET MOVES INTO THE REGION. STRONG LOW
LEVEL INVERSION WILL LIMIT GUSTS AND EXPECT STRONGEST WINDS OVER
NEARSHORE WATERS. SEAS BUILDING OVER SOUTHERN WATERS. VSBY
REDUCED IN SHOWERS ESPECIALLY DURING THE AFTERNOON. ISOLATED
TSTMS LATE SAT.
TONIGHT...SW GUSTS TO 25 KT EARLY ACROSS EASTERN WATERS.
WIDESPREAD SHOWERS AND ISOLATED TSTMS. ROUGH SEAS SOUTH OCEAN
WATERS.
SUNDAY...ANOTHER PULSE OF SW WIND GUSTS TO 25 KT EXPECTED IN THE
AFTERNOON.
OUTLOOK...SUNDAY NIGHT THROUGH WEDNESDAY...
EXPECT SEAS OF 5 TO 7 FEET ON THE OUTER WATERS SUNDAY NIGHT. SEAS
WILL DIMINISH MONDAY THROUGH WEDNESDAY AS HIGH PRESSURE BUILDS
OVER THE WATERS. SCA SEAS WILL CONTINUE ON THE OUTER WATERS
THROUGH MONDAY AFTERNOON. WESTERLY WINDS WILL FLIRT WITH SCA
CRITERIA SUNDAY NIGHT.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...NONE.
NH...NONE.
RI...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR
ANZ230>237-251.
SMALL CRAFT ADVISORY UNTIL 6 AM EDT SUNDAY FOR ANZ250.
SMALL CRAFT ADVISORY UNTIL 6 AM EDT SUNDAY FOR ANZ254>256.
&&
$$
SYNOPSIS...KJC/RLG
NEAR TERM...KJC/DOODY
SHORT TERM...KJC
LONG TERM...RLG
AVIATION...KJC/RLG
MARINE...KJC/RLG
AREA FORECAST DISCUSSION
NWS MIAMI FL
957 AM EDT SAT MAY 11 2013
.UPDATE...
CHANGES ARE NOT BEING PLANNED FOR THE MORNING UPDATES AT THIS
TIME. CONVECTIVE PARAMETERS LOOK SIMILAR TO YESTERDAY WITH SOME
MINOR FLUCTUATIONS. A MID LAYER INVERSION REMAINS ALTHOUGH IT IS
AT A LOWER LEVEL AROUND 700 MB VERSUS 500 MB FROM YESTERDAY
MORNING. STILL, THE LOW LEVELS REMAIN QUITE UNSTABLE SO THIS WOULD
SUGGEST THAT DEEP CONVECTION WILL ONCE AGAIN BE DELAYED. THIS ALSO
IS WHAT THE HRRR IS DEPICTING WITH STRONG CONVECTIVE ACTIVITY
DEVELOPING AROUND THE 20-21Z TIME FRAME. STORM MOTION WILL AGAIN
BE VERY SLOW WITH A DRIFT TOWARDS THE EAST. THE MAX CAPE TODAY IS
A LITTLE LOWER AT LESS THAN 2000 J/KG BUT THE 500 MB TEMPERATURE
COOLED BY 1 DEGREE CELSIUS WHICH OFFSETS THE INSTABILITY. SO ALL
THINGS CONSIDERED, FORECAST WILL REMAIN UNCHANGED.
KOB
&&
.PREV DISCUSSION... /ISSUED 818 AM EDT SAT MAY 11 2013/
AVIATION...
GENERALLY...VFR CONDITIONS WILL PREVAIL THROUGH THE WEEKEND. MOSTLY
CLEAR SKIES AND CALM WINDS EARLY THIS MORNING WILL GIVE WAY TO
INCREASING CUMULUS AND SOUTHEAST WINDS AT 10-15 KTS. SCATTERED
SHOWERS AND THUNDERSTORMS ARE EXPECTED TO DEVELOP THIS AFTERNOON AND
PERSIST THROUGH EARLY EVENING. CURRENT CONFIDENCE IN TIMING/LOCATION
OF CONVECTION IS NOT HIGH...SO HAVE ONLY PLACED VCSH IN TAFS FOR 12Z
ISSUANCE. BEST CHANCE OF THUNDERSTORMS IS KPBI AND RISK OF SHOWERS
ARE LOWEST IN KAPF...WHERE POP BELOW 20 PERCENT DIDNT WARRANT
MENTION IN TAF. ANY THUNDERSTORMS COULD HAVE GUSTY WINDS AND
SIGNIFICANT BUT BRIEF FLIGHT RESTRICTIONS. THIS EVENING...ACTIVITY
SHOULD DIMINISH AND A RETURN TO MOSTLY CLEAR SKIES AND LIGHT WINDS.
PREV DISCUSSION... /ISSUED 411 AM EDT SAT MAY 11 2013/
DISCUSSION...
WATER VAPOR AND NAM ANALYSIS FROM THIS MORNING SHOWED AN UPPER
RIDGE STRETCHING FROM THE SOUTHERN GULF AND WESTERN CARIBBEAN
NORTHEASTWARD OVER SOUTH FLORIDA INTO THE WESTERN ATLANTIC. AN
UPPER LEVEL TROUGH WAS DIGGING INTO THE PLAINS...AND A CUT OFF
UPPER LOW REMAINED OVER BAJA CALIFORNIA AND WESTERN MEXICO. AT THE
SURFACE...THE RIDGE REMAINED OVER THE WESTERN ATLANTIC...WITH THE
RIDGE AXIS OVER NORTH CENTRAL FLORIDA.
THE UPPER LEVEL RIDGE WILL SHIFT EAST AND FLATTEN OUT OVER SOUTH
FLORIDA TODAY AS THE UPPER LEVEL TROUGH DIGS INTO THE SOUTHEAST.
TEMPERATURES AT 500MB AND ABOVE WILL WARM TODAY...SO THE HAIL
THREAT WILL BE SLIGHTLY LOWER THAN ON FRIDAY. HOWEVER...0-6KM
SHEAR WILL INCREASE TO AROUND 30 KNOTS...WITH SOMEWHAT DRIER AIR
IN THE MID LEVELS. SO THE WIND THREAT MAY ACTUALLY BE
HIGHER...WITH STRONG TO ISOLATED SEVERE STORMS POSSIBLE. SPC HAS
ALSO ADDED THE EAST COAST IN 5 PERCENT WIND AND HAIL THREAT FOR
TODAY. THE FLOW AT 850MB AND ABOVE WILL BE LIGHT OUT OF THE WEST
TO NORTHWEST. SO STORMS WILL FORM CLOSER TO THE EAST COAST...AND
MOVE BACK TOWARDS THE EAST COAST THIS AFTERNOON. STORM MOTION WILL
BE SLOW...SO LOCALLY HEAVY RAINFALL IS POSSIBLE WHERE STORMS
DEVELOP. MODELS INDICATE DECENT AMOUNTS OF QPF...BUT POP GUIDANCE
IS 20-30 PERCENT. THE POP GUIDANCE HAS BEEN WAY TOO LOW THE PAST
SEVERAL DAYS...SO WENT ABOVE GUIDANCE THE NEXT SEVERAL DAYS...IN
THE 30-50 PERCENT RANGE ACROSS THE INTERIOR AND EAST.
AN MCS IS SUPPOSED TO DEVELOP ACROSS THE NORTH CENTRAL GULF THIS
AFTERNOON AND TRACK EAST INTO NORTHERN AND CENTRAL FLORIDA LATE
THIS AFTERNOON. MODELS DO NOT HANDLE THESE FEATURES ALL THAT
WELL...SO IT IS POSSIBLE THE TAIL END OF THE SHOWERS AND STORMS
COULD MOVE INTO THE OFFSHORE GULF WATERS LATE THIS AFTERNOON INTO
THE EVENING...SO HAVE SLIGHT CHANCE POPS FOR THIS POSSIBILITY.
SHOWERS AND THUNDERSTORMS ACROSS THE EASTERN HALF OF THE AREA WILL
WIND DOWN THIS EVENING WITH THE LOSS OF DAYTIME HEATING. TEMPS
WILL BE WARM TODAY AND TONIGHT...WITH HIGHS IN THE MID 80S TO
LOWER 90S AND LOWS IN THE MID 60S TO MID 70S.
A COLD FRONT WILL MOVE INTO NORTHERN FLORIDA ON SUNDAY. FLOW ALOFT
WILL BE LIGHT OUT OF THE WEST...SO STORMS WILL CONCENTRATE ACROSS
THE INTERIOR AND TOWARDS THE EAST COAST. TEMPS ALOFT WILL WARM
SLIGHTLY...AND SHEAR WILL BE LESS...BUT THERE COULD BE SOME STRONG
STORMS. TEMPS WILL REMAIN SIMILAR TO SATURDAY.
THE UPPER LEVEL TROUGH WILL DIG DOWN INTO THE FLORIDA PENINSULA ON
MONDAY...AND THE FRONT WILL ALSO MOVE INTO SOUTH FLORIDA. THE
REGION WILL ALSO BE IN THE RIGHT ENTRANCE REGION OF 90-100KT JET
STREAK. THE GFS IS INDICATING 30 KT 0-6KM BULK SHEAR IN THE
AFTERNOON. HOWEVER...CAPE IS EXPECTED TO BE MUCH LOWER THAN THE
OVER THE WEEKEND. SO THE BEST CHANCE OF STORMS WILL BE ACROSS THE
NORTH AND NORTHEAST IN THE MORNING TO EARLY AFTERNOON...AND THEN
ACROSS THE SOUTHEAST AND ESPECIALLY MIAMI-DADE COUNTY IN THE
AFTERNOON.
COOLER AND MUCH DRIER AIR WILL THEN MOVE INTO THE REGION MONDAY
NIGHT AND TUESDAY...AND CONDITIONS WILL REMAIN MOSTLY DRY THROUGH
THE END OF THE WEEK. HIGH PRESSURE WILL BUILD INTO THE SOUTHEAST
AND WESTERN ATLANTIC TUESDAY...WITH INCREASING NORTHEASTERLY FLOW
OVER THE LOCAL WATERS. HIGH TEMPERATURES ARE EXPECTED TO ONLY BE
IN THE LOW TO MID 80S THROUGH THE END OF WEEK. LOW TEMPERATURES
WILL DROP OFF INTO THE 50S ACROSS THE INTERIOR EACH NIGHT...WITH
60S TO AROUND 70 DEGREES FOR THE METRO AREAS.
MARINE...
MOSTLY SOUTHEAST TO SOUTH WIND THROUGH THE WEEKEND AT LESS THAN 15
KNOTS WITH SEAS LESS THAN 3 FEET. HIGH PRESSURE BEGINS TO BUILD
NORTH OF THE REGION EARLY NEXT WEEK WITH WINDS AND SEAS BUILDING
BUT REMAINING BELOW ADVISORY CRITERIA.
FIRE WEATHER...
SCATTERED SHOWERS AND THUNDERSTORMS ARE EXPECTED EACH AFTERNOON
THIS WEEKEND ACROSS THE INTERIOR AND TOWARDS THE EAST COAST.
MINIMUM RELATIVE HUMIDITY VALUES WILL REMAIN WELL ABOVE CRITICAL
VALUES EACH DAY THIS WEEKEND. DRIER AIR WILL BEGIN TO FILTER INTO
THE REGION MONDAY AFTERNOON...AND MINIMUM RELATIVE HUMIDITY VALUES
ARE EXPECTED TO BE NEAR 35 PERCENT ACROSS THE NORTHWEST INTERIOR
TUESDAY AFTERNOON.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 87 73 87 71 / 40 30 50 30
FORT LAUDERDALE 87 72 87 74 / 40 30 50 20
MIAMI 89 74 88 73 / 40 30 40 20
NAPLES 87 72 85 71 / 10 20 20 20
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS TALLAHASSEE FL
652 AM EDT Sat May 11 2013
.NEAR TERM [through This Afternoon]...
Updated at: 650 AM EDT
The overall progression of the weather elements in the near term
appears to be on track. The HRRR and RAP continue to perform best
with the position and timing of upstream convective activity. We
still expect rain and some thunderstorms to gradually spread into
the western part of our area around 16 UTC, and then affect the rest
of the area through the remainder of the afternoon. The best chances
for rain still appear to be in the Florida Panhandle and Big Bend,
and the immediate adjacent row of counties in south Georgia. Thus,
no major changes were made - although the thinking with respect to
severe weather potential has changed slightly.
Objective analysis continues to show a pseudo-warm front or surface
pressure trough from just off the Louisiana coast to near our
offshore buoy (42039). This is supported by a noticeable thetae
gradient and wind shift offshore. Not surprisingly, this is also the
zone where the strongest convection has been developing upstream.
Given the current position of the mesoscale boundary offshore, we
may see the most intense storms today focused over the coastal
waters. This is a theory that is supported by recent high-resolution
model runs, with strongest average updraft strengths over the Gulf.
Therefore, most of our land areas could just see some general rain
showers with some embedded thunderstorms.
However, we still have to be wary of several scenarios that could
bring stronger thunderstorms to our land areas. First, the boundary
could surge north into the Florida Big Bend, which would support an
isolated severe weather threat in our Florida zones east of the
Apalachicola River. Second, the eastern part of our area could
receive greater insolation and heating ahead of the advancing cirrus
shield from the upstream convection. This could support a ribbon of
greater instability east of a line from AAF-ABY, and scattered
storms could develop in the weakly capped environment as large scale
forcing increases ahead of the advancing mid-level MCV associated
with the current convection near coastal Louisiana. Either way, the
situation still seems to indicate a threat for isolated strong or
severe storms - but mainly in southern and eastern areas.
&&
.SHORT TERM [Tonight through Monday]...
The 00 UTC NWP guidance continues to forecast an unusually deep
longwave trough over the eastern CONUS Sunday and Monday. The PoP
will decrease from northwest to southeast Sunday as dry air
advection develops. The highest PoP, 30-40%, will be from
Tallahassee southward and eastward tonight and Sunday, with the PoP
decreasing below 10% Sunday evening. The core of the cooler and
drier airmass won`t reach our forecast area until Monday. Highs on
Sunday will be in the lower 80s, but only in the 70s (below average)
Monday. Lows on Monday morning will be in the 50s (also below
average). The low humidity and relatively breezy conditions on
Monday will make it feel quite pleasant for mid May, when it usually
begins to get warm and humid.
&&
.LONG TERM [Monday Night through Friday]...
Deep layer ridging will build into the region for the middle of the
week followed by a low amplitude trough late Thursday into
Friday. There will be a slight to low end chance of rain on
Friday, otherwise the extended period will be dry. The week will
begin with below normal temperatures and gradually moderate to
seasonal levels by Thursday. The coldest temperatures will be
Tuesday morning when upper 40s to around 50 degrees are forecast.
&&
.AVIATION [Through 12 UTC Sunday]...
Updated at: 650 AM EDT
Mid-high level cloud cover has cleared out, leading to some patchy
fog and low stratus across the area around sunrise. This is most
established at DHN and ECP where CIGS are near or below airport
minimums. Elsewhere, flight categories should remain in the MVFR or
IFR range. Fog and low stratus should generally lift by mid morning.
Rain will spread into the area from west to east, first affecting
DHN and ECP around 16 UTC. There may be a few thunderstorms, but
confidence was not high enough to include in a prevailing group.
Scattered storms would be most likely between 18-00 UTC at TLH and
VLD. Low CIGS may develop again tonight. For now kept things MVFR.
&&
.MARINE...
Aside from the increased rain chances, weekend boaters will be
treated to low winds and seas (outside of scattered thunderstorms).
This will change Sunday night as the rather strong area of high
pressure builds across the Southeast behind a cold front, causing
winds to increase to 15 to 20 KT. These offshore winds may remain at
exercise caution levels through Tuesday morning.
&&
.FIRE WEATHER...
Wetting rains are expected over a good portion of the area today.
Drier air will arrive behind a cold front on Sunday Night with very
low RH for May expected on Monday. Despite the minimum RH around
25%, other fuel-dependent red flag criteria may not be met. Thus,
while red flag conditions seem somewhat uncertain, there is high
confidence that Monday will be a breezy, dry day with high
dispersion values.
&&
.HYDROLOGY...
The 00 UTC WPC 5-day rainfall accumulation forecast continues to
show our between one half and one inch over our forecast area,
mainly this weekend, and with the highest totals west of
Tallahassee. None of the experimental hydrologic ensembles forecast
minor flooding for our river forecast points over the next several
days. The maximum of maximum 6-hour QPF amounts from the various
Convection Allowing Models (CAM), a worst case scenario, show
isolated narrow bands of 3-4 inches. Neither the area coverage or
magnitude of these values would indicate enough of a threat for a
flash flood watch for today`s rain.
&&
.PRELIMINARY POINT TEMPS/POPS...
Tallahassee 83 66 82 53 80 / 70 40 30 10 0
Panama City 77 67 81 57 78 / 70 40 20 10 0
Dothan 81 63 79 50 78 / 70 40 10 0 0
Albany 85 64 81 50 76 / 60 40 10 0 0
Valdosta 86 64 81 52 77 / 70 40 30 10 0
Cross City 84 66 82 57 80 / 40 30 40 10 0
Apalachicola 79 67 79 59 76 / 60 30 30 10 0
&&
.TAE WATCHES/WARNINGS/ADVISORIES...
FL...None.
GA...None.
AL...None.
GM...None.
&&
$$
NEAR TERM...Lamers
SHORT TERM...Fournier
LONG TERM...Barry
AVIATION...Lamers
MARINE...Fournier
FIRE WEATHER...Lamers
HYDROLOGY...Fournier
AREA FORECAST DISCUSSION
NWS PEACHTREE CITY GA
1045 AM EDT SAT MAY 11 2013
.UPDATE...
COLD FRONT IS CURRENTLY SITUATED FROM THE EASTERN GREAT LAKES
THROUGH THE MIDDLE ATLANTIC TO THE CENTRAL GULF COAST. THE FRONT
WILL CONTINUE TO MOVE EASTWARD THROUGH THE DAY AND THROUGH THE
REMAINDER OF THE CWFA THIS EVENING/OVERNIGHT.
EARLIER ADJUSTMENTS TO THE GRIDS INCLUDED SOME FINE TUNING OF THE
CLOUD COVER...POPS...AND HOURLY TEMPS/DEWPOINTS. MAX TEMPS LOOK
GOOD FOR NOW. MAIN FORECAST PROBLEM OF THE DAY WILL BE POPS.
SIGNIFICANT CLOUD COVER WILL HELP KEEP SURFACE INSTABILITY
MARGINAL UNDERCUTTING SURFACE HEATING. IN ADDITION...CONVECTION
ALONG THE GULF COAST MAY DISRUPT THE MOISTURE FLOW NORTHWARD.
NAM...GFS...ETC DONT HAVE A REALLY GOOD HANDLE OF THE GULF
CONVECTION. HOWEVER...THE LATEST RUN OF THE HRRR SEEMS TO HANDLE
THE CONVECTION REASONABLY. DO THINK SCT STORMS WILL DEVELOP ALONG
THE FRONT LATER IN THE AFTERNOON...MOSTLY SHOWERS WITH A FEW
THUNDERSTORMS. MAY END UP HAVING TO REDUCE POPS IN THE SOUTH TO
CHANCE...IF THEY GULF CONVECTION CONTINUES TO HOLD TOGETHER.
&&
.PREV DISCUSSION... /ISSUED 747 AM EDT SAT MAY 11 2013/
PREV DISCUSSION... /ISSUED 447 AM EDT SAT MAY 11 2013/
SHORT TERM /TODAY THROUGH SUNDAY/...
CURRENT SATELLITE LOOP SHOWS A LARGE MOISTURE PLUME EXTENDING FROM
THE NEW ENGLAND STATES...DOWN THE EASTERN SEABOARD...AND OVER TO THE
TX GULF COAST. THERE IS A NICE AREA OF ENHANCED SHOWERS AND ISOLATED
THUNDERSTORMS ACROSS TN AND AL BUT THIS PRECIPITATION IS NOT
EXPECTED TO MAKE IT INTO GA UNTIL LATER THIS MORNING INTO THIS
AFTERNOON. THE ACTUAL FRONT ASSOCIATED WITH THIS MOISTURE PLUME IS
BACK ACROSS TN NEAR MEMPHIS AND IT IS MOVING SLOWLY EAST. THIS FRONT
IS EXPECTED TO PUSH INTO NW GA BY 18Z TODAY AND MOVE SOUTH AND EAST
THROUGH THE SHORT TERM. IT SHOULD FINALLY PUSH OFF THE GA COAST BY
18Z SUN. AS THIS FRONT MOVES INTO THE AREA IT WILL BRING INCREASED
MOISTURE AND ACT AS A CATALYST FOR SHRA/TSRA DEVELOPMENT TODAY AND
TONIGHT. INSTABILITIES INCREASE TODAY WITH CAPES GETTING INTO THE
1000-1500 J/KG RANGE AND LIS GETTING DOWN INTO THE -1 TO -3 RANGE BY
18Z-00Z. SHEAR IS EXPECTED TO BE VERY WEAK AND LAPSE RATES ARE NOT
THAT IMPRESSIVE EITHER SO NOT EXPECTING ANY SEVERE STORMS TODAY.
ONCE THIS FRONT MOVES EAST OF THE AREA...A MUCH DRIER AIRMASS MOVES
IN WITH DEWPOINTS IN THE UPPER 30S TO LOWER 40S EXPECTED BY 18Z SUN.
01
LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
GFS/ECMWF MODEL GUIDANCE ARE IN GOOD AGREEMENT WITH A BROAD UPPER
UPPER LEVEL TROUGH MOVING THROUGH THE EASTERN U.S. THROUGH MON.
SURFACE HIGH PRESSURE WILL BUILD INTO GA WITH GENERALLY CLEAR
SKIES AND VERY DRY AND COOL AIR ALLOWING TEMPERATURES TO PLUNGE
ONCE AGAIN. AT THIS TIME SUN NIGHT MINS SHOULD BE FROM 10-15
DEGREES BELOW NORMAL WHILE MON MAXES WILL BE AROUND 10 DEGREES
BELOW NORMAL. A RAPID WARM-UP IS EXPECTED TUE THROUGH THU AS AN
UPPER LEVEL RIDGE DEVELOPS AND MOVES INTO THE SOUTHEAST U.S. MIN
AND MAX TEMPERATURES DURING THIS PERIOD WILL RETURN TO NEAR OR A
FEW DEGREES ABOVE NORMAL. THE GFS AND ECMWF MODELS BEGIN TO DIFFER
IN THEIR SOLUTIONS FOR THE END OF THE WEEK. THE GFS DEPICTS A MORE
ORGANIZED COLD FRONT MOVING THROUGH THE TN VALLEY THU NIGHT AND
FRI WHILE THE ECMWF HAS A WEAK PRESSURE PATTERN ALOFT. WILL GO
WITH THE GFS FOR NOW INDICATING ISOLATED TO SCATTERED TSTMS WITH
THE DIURNAL HEATING ON THU BECOMING MORE INFLUENCED BY THE
APPROACHING FRONT ON FRIDAY.
16
AVIATION...
12Z UPDATE...
VFR CONDITIONS TO START BUT THINGS WILL CHANGE WITH FRONTAL
SYSTEM MOVING IN THIS AFTERNOON/EVENING. THERE ARE A FEW PLACES
WITH SOME LOW STRATUS BUT THAT SHOULD BURN OFF SHORTLY AFTER
SUNRISE. INCREASED CLOUD COVER EXPECTED TODAY WITH CEILINGS
COMING DOWN THROUGH 18Z. THERE AREA SOME SCT SHOWERS ACROSS NW GA
THIS MORNING BUT KEEPING IT OUT OF THE TAF SITES UNTIL AFTER 18Z.
A DRIER AIRMASS MOVES INTO NW GA BY 00Z SUN SO SHOULD SEE ANY
PRECIP THAT IS STILL LINGERING AROUND THE AREA DISSIPATE BY 06Z.
ONLY KEEPING SHRA/TSRA IN THE TAFS THROUGH 00Z SUN. WINDS WILL
STAY OUT OF THE W TO SW IN THE 5-10KT RANGE. WILL SEE SOME HIGHER
GUST IN AND AROUND TSRA DEVELOPMENT.
//ATL CONFIDENCE...12Z UPDATE...
CONFIDENCE MEDIUM TO HIGH ON ALL ELEMENTS.
01
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 79 56 77 43 / 50 30 5 0
ATLANTA 76 55 73 46 / 60 30 5 0
BLAIRSVILLE 72 49 67 38 / 30 20 10 0
CARTERSVILLE 75 53 72 41 / 40 20 5 0
COLUMBUS 79 59 78 47 / 60 40 10 0
GAINESVILLE 74 54 72 44 / 50 20 5 0
MACON 81 58 80 44 / 60 50 10 0
ROME 75 53 73 40 / 40 20 5 0
PEACHTREE CITY 75 54 74 38 / 60 30 5 0
VIDALIA 85 65 83 50 / 50 50 20 0
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...NLISTEMAA
AREA FORECAST DISCUSSION
NWS DES MOINES IA
1006 AM CDT SAT MAY 11 2013
.UPDATE...
ISSUED AT 957 AM CDT SAT MAY 11 2013
UPDATING ZONES TO REFLECT CHANCE OF SPRINKLES ACROSS THE NORTHEAST
TODAY. THOUGH MOISTURE REMAINS LIMITED...SECOND COLD FRONT WITH
COLD AIR ALOFT WILL INCREASE CU FIELD NORTHEAST AND POSSIBLY
PRODUCE A FEW LIGHT SHOWERS ALONG WITH GUSTY WINDS THIS AFTERNOON.
&&
.SHORT TERM.../TODAY/
ISSUED AT 325 AM CDT SAT MAY 11 2013
MAIN CONCERNS TODAY WILL BE SUBTLE PRECIP TRENDS AND WIND. UPPER
LEVEL TROUGH...INCLUDING POTENT ND/MN PV ANOMALY...CONTINUES TO
ADVANCE TOWARD THE GREAT LAKES EARLY THIS MORNING. WIDELY SCATTERED
LIGHT SHOWERS HAVE DEVELOPED AHEAD OF THIS FEATURE INTO IA AND ARE
PRIMARILY THERMODYNAMICALLY FORCED. LATEST RAP ANALYSIS SHOWS NICE
COLD FRONT ALOFT WITH RELATIVELY HIGHER BASED THETA-E ADVECTION AND
FRONTOGENETICAL FORCING. RESULTANT PRECIP IS HIGH BASED...TYPICALLY
7K FT OR HIGHER...AND STRUGGLING TO REACH THE GROUND MUCH.
EXTRAPOLATION SUGGESTS WHAT PRECIP THERE IS WILL ADVANCE SOUTH AND
EAST EXITING SE TOWARD 12Z. PRECIP OVER NRN MN IS NOT EXPECTED TO
AFFECT OUR FORECAST AREA BY AFTERNOON DUE TO TRAJECTORIES AND
INCREASING SUBSIDENCE. SOUNDINGS SHOW SOME POTENTIAL FOR SURFACE
BASED REDEVELOPMENT BUT ADEQUATE MOISTURE IS CERTAINLY QUESTIONABLE.
08Z SURFACE ANALYSIS SHOWS INITIAL WIND SHIFT/TROUGH ALONG
CARROLL-WEBSTER CITY-MASON CITY LINE WITH TRUE COLD FRONT SEEMING TO
LACK BEHIND JUST REACHING IA/MN BORDER. MOS GUIDANCE AND SOUNDINGS
SUGGEST WIND WILL INCREASE WITH MIXING TODAY...APPROACHING SUSTAINED
ADVISORY CRITERIA /26 KTS/ NORTHEAST. SOUNDINGS DEPICT MIXING TO
2KM OR MORE BY AFTERNOON WITH MIXED LAYER WINDS SUGGESTING GUSTS
INTO THE LOW 30S /KTS/ NE THIRD.
MAX TEMPS ARE GENERALLY AT OR BELOW MOS GUIDANCE EVEN WITH THIS DEEP
MIXING. THESE SOUNDINGS STRUGGLE TO REACH MOS...LIKELY DUE TO
INFLUENCE OF CLIMO. DEWPOINTS WILL ALSO BE QUITE LOW...DROPPING INTO
THE 20S DUE TO UPSTREAM AIRMASS AND MIXING. MODEL SKIN DEWPOINTS
SEEM TOO HIGH...LIKELY OVERDONE DUE TO EVAPOTRANSPIRATION BEING
BEHIND SCHEDULE.
.LONG TERM.../TONIGHT THROUGH FRIDAY/
ISSUED AT 325 AM CDT SAT MAY 11 2013
A SOMEWHAT HIGH AMPLITUDE UPPER AIR PATTERN INITIALLY GIVES WAY TO
A MORE ZONAL...OR AT LEAST A LOWER AMPLITUDE UPPER PATTERN BY
THE MIDDLE OF NEXT WEEK. AN UPPER RIDGE OVER THE PACIFIC NORTHWEST
BUILDS INTO THE NORTHERN PLAINS BY TUESDAY. AS IT RIDGE MOVES
EAST...IT IS FLATTENED BY A SHORTWAVE MOVING OVER THE RIDGE ACROSS
SOUTHERN CANADA. MEANWHILE...AN OLD UPPER LOW INITIALLY OVER
NORTHWEST MEXICO EJECTS INTO THE CENTRAL PLAINS AND GETS ABSORBED
INTO THE WESTERLIES. THE SHORT RANGE MODELS ARE IN FAIR AGREEMENT
WITH THE EVALUATION OF THE PATTERN THROUGH TUESDAY. AFTER
TUESDAY...THE 00Z GFS/ECMWF START TO DIVERGE WITH THE DETAILS OF
THE UPPER PATTERN AND ASSOCIATED SURFACE REFLECTION. THE 00Z GFS
HAS MORE AMPLITUDE ALLOWING THE SURFACE FRONT TO MOVE SOUTH OF
IOWA BY MIDWEEK. THE ECMWF HAVING A FLATTER LOOKING PATTERN NEVER
PUSHES THE BOUNDARY THROUGH THE STATE BEFORE LIFTING IT BACK NORTH
LATE IN THE WEEK.
THE SHORT RANGE MODELS ARE IN GOOD AGREEMENT CONCERNING THE
POSITION OF THE POLAR SURFACE HIGH OVER THE MISSOURI VALLEY BY 12Z
SUNDAY. IT WOULD APPEAR THAT A GOOD RADIATION COOLING SCENARIO
SHOULD OCCUR OVER WESTERN IOWA SUNDAY MORNING. WITH LIGHT WINDS
AND LOWS APPROACHING FREEZING...WILL ISSUE A FROST ADVISORY FOR
PART OF WESTERN AND NORTHERN SECTIONS OF THE FORECAST AREA. SOME
CONCERN ABOUT LOW DEWPOINTS...BUT WHERE THE WIND IS VERY
LIGHT...THERE SHOULD BE ENOUGH FROST FORMATION TO WARRANT
ADVISORY.
NEXT UP WILL BE THE RAPID WARM UP EARLY NEXT WEEK AS BEFORE MENTION
UPPER RIDGE MOVES ACROSS THE NORTHERN CONUS. MODELS ARE IN GOOD
AGREEMENT WITH VERY WARM 850 MB TEMPERATURES ON TUESDAY IN THE
WARM SECTOR AHEAD OF THE APPROACHING COLD FRONT. BASICALLY USED THE
PREVIOUS FORECAST FOR HIGHS WHICH LOOK ON TARGET.
THE PATTERN LOOKS MORE ACTIVE CONCERNING THUNDERSTORMS FROM THE
MIDDLE OF NEXT WEEK THROUGH THE END OF THE FORECAST PERIOD. THERE
SHOULD BE AN WEST TO EAST BOUNDARY IN THE AREA WHICH CLIMATOLOGICALLY
SUPPORTS THUNDERSTORM CHANCES.
&&
.AVIATION...11/12Z
ISSUED AT 654 AM CDT SAT MAY 11 2013
VFR CONDITIONS ARE ANTICIPATED THROUGHOUT THE PERIOD. 12Z SURFACE
ANALYSIS SHOWS WIND SHIFT/PRESSURE TROUGH JUST EXITING SERN IA
WITH ACTUAL COLD FRONT FOLLOWING CLOSE BEHIND. GUSTY NW WINDS ARE
ANTICIPATED BEHIND THE FRONT TODAY WITH GUSTS OVER 30 KTS AT
TIMES. MID CLOUDS WILL EXIT SRN IA THIS MORNING FOLLOWED BY SCT-
BKN VFR CLOUDS DURING PEAK HEATING. OTHERWISE CLEAR SKIES ARE EXPECTED.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...
FROST ADVISORY FROM 3 AM TO 9 AM CDT SUNDAY FOR AUDUBON-CALHOUN-
CARROLL-CASS-CERRO GORDO-CRAWFORD-EMMET-GREENE-GUTHRIE-HANCOCK-
HUMBOLDT-KOSSUTH-PALO ALTO-POCAHONTAS-SAC-WEBSTER-WINNEBAGO-
WORTH-WRIGHT.
&&
$$
UPDATE...REV
SHORT TERM...SMALL
LONG TERM...JOHNSON
AVIATION...SMALL
AREA FORECAST DISCUSSION
NWS DES MOINES IA
655 AM CDT SAT MAY 11 2013
.SHORT TERM.../TODAY/
ISSUED AT 325 AM CDT SAT MAY 11 2013
MAIN CONCERNS TODAY WILL BE SUBTLE PRECIP TRENDS AND WIND. UPPER
LEVEL TROUGH...INCLUDING POTENT ND/MN PV ANOMALY...CONTINUES TO
ADVANCE TOWARD THE GREAT LAKES EARLY THIS MORNING. WIDELY SCATTERED
LIGHT SHOWERS HAVE DEVELOPED AHEAD OF THIS FEATURE INTO IA AND ARE
PRIMARILY THERMODYNAMICALLY FORCED. LATEST RAP ANALYSIS SHOWS NICE
COLD FRONT ALOFT WITH RELATIVELY HIGHER BASED THETA-E ADVECTION AND
FRONTOGENETICAL FORCING. RESULTANT PRECIP IS HIGH BASED...TYPICALLY
7K FT OR HIGHER...AND STRUGGLING TO REACH THE GROUND MUCH.
EXTRAPOLATION SUGGESTS WHAT PRECIP THERE IS WILL ADVANCE SOUTH AND
EAST EXITING SE TOWARD 12Z. PRECIP OVER NRN MN IS NOT EXPECTED TO
AFFECT OUR FORECAST AREA BY AFTERNOON DUE TO TRAJECTORIES AND
INCREASING SUBSIDENCE. SOUNDINGS SHOW SOME POTENTIAL FOR SURFACE
BASED REDEVELOPMENT BUT ADEQUATE MOISTURE IS CERTAINLY QUESTIONABLE.
08Z SURFACE ANALYSIS SHOWS INITIAL WIND SHIFT/TROUGH ALONG
CARROLL-WEBSTER CITY-MASON CITY LINE WITH TRUE COLD FRONT SEEMING TO
LACK BEHIND JUST REACHING IA/MN BORDER. MOS GUIDANCE AND SOUNDINGS
SUGGEST WIND WILL INCREASE WITH MIXING TODAY...APPROACHING SUSTAINED
ADVISORY CRITERIA /26 KTS/ NORTHEAST. SOUNDINGS DEPICT MIXING TO
2KM OR MORE BY AFTERNOON WITH MIXED LAYER WINDS SUGGESTING GUSTS
INTO THE LOW 30S /KTS/ NE THIRD.
MAX TEMPS ARE GENERALLY AT OR BELOW MOS GUIDANCE EVEN WITH THIS DEEP
MIXING. THESE SOUNDINGS STRUGGLE TO REACH MOS...LIKELY DUE TO
INFLUENCE OF CLIMO. DEWPOINTS WILL ALSO BE QUITE LOW...DROPPING INTO
THE 20S DUE TO UPSTREAM AIRMASS AND MIXING. MODEL SKIN DEWPOINTS
SEEM TOO HIGH...LIKELY OVERDONE DUE TO EVAPOTRANSPIRATION BEING
BEHIND SCHEDULE.
.LONG TERM.../TONIGHT THROUGH FRIDAY/
ISSUED AT 325 AM CDT SAT MAY 11 2013
A SOMEWHAT HIGH AMPLITUDE UPPER AIR PATTERN INITIALLY GIVES WAY TO
A MORE ZONAL...OR AT LEAST A LOWER AMPLITUDE UPPER PATTERN BY
THE MIDDLE OF NEXT WEEK. AN UPPER RIDGE OVER THE PACIFIC NORTHWEST
BUILDS INTO THE NORTHERN PLAINS BY TUESDAY. AS IT RIDGE MOVES
EAST...IT IS FLATTENED BY A SHORTWAVE MOVING OVER THE RIDGE ACROSS
SOUTHERN CANADA. MEANWHILE...AN OLD UPPER LOW INITIALLY OVER
NORTHWEST MEXICO EJECTS INTO THE CENTRAL PLAINS AND GETS ABSORBED
INTO THE WESTERLIES. THE SHORT RANGE MODELS ARE IN FAIR AGREEMENT
WITH THE EVALUATION OF THE PATTERN THROUGH TUESDAY. AFTER
TUESDAY...THE 00Z GFS/ECMWF START TO DIVERGE WITH THE DETAILS OF
THE UPPER PATTERN AND ASSOCIATED SURFACE REFLECTION. THE 00Z GFS
HAS MORE AMPLITUDE ALLOWING THE SURFACE FRONT TO MOVE SOUTH OF
IOWA BY MIDWEEK. THE ECMWF HAVING A FLATTER LOOKING PATTERN NEVER
PUSHES THE BOUNDARY THROUGH THE STATE BEFORE LIFTING IT BACK NORTH
LATE IN THE WEEK.
THE SHORT RANGE MODELS ARE IN GOOD AGREEMENT CONCERNING THE
POSITION OF THE POLAR SURFACE HIGH OVER THE MISSOURI VALLEY BY 12Z
SUNDAY. IT WOULD APPEAR THAT A GOOD RADIATION COOLING SCENARIO
SHOULD OCCUR OVER WESTERN IOWA SUNDAY MORNING. WITH LIGHT WINDS
AND LOWS APPROACHING FREEZING...WILL ISSUE A FROST ADVISORY FOR
PART OF WESTERN AND NORTHERN SECTIONS OF THE FORECAST AREA. SOME
CONCERN ABOUT LOW DEWPOINTS...BUT WHERE THE WIND IS VERY
LIGHT...THERE SHOULD BE ENOUGH FROST FORMATION TO WARRANT
ADVISORY.
NEXT UP WILL BE THE RAPID WARM UP EARLY NEXT WEEK AS BEFORE MENTION
UPPER RIDGE MOVES ACROSS THE NORTHERN CONUS. MODELS ARE IN GOOD
AGREEMENT WITH VERY WARM 850 MB TEMPERATURES ON TUESDAY IN THE
WARM SECTOR AHEAD OF THE APPROACHING COLD FRONT. BASICALLY USED THE
PREVIOUS FORECAST FOR HIGHS WHICH LOOK ON TARGET.
THE PATTERN LOOKS MORE ACTIVE CONCERNING THUNDERSTORMS FROM THE
MIDDLE OF NEXT WEEK THROUGH THE END OF THE FORECAST PERIOD. THERE
SHOULD BE AN WEST TO EAST BOUNDARY IN THE AREA WHICH IS
COSMOLOGICALLY SUPPORTS THUNDERSTORM CHANCES.
&&
.AVIATION...11/12Z
ISSUED AT 654 AM CDT SAT MAY 11 2013
VFR CONDITIONS ARE ANTICIPATED THROUGHOUT THE PERIOD. 12Z SURFACE
ANALYSIS SHOWS WIND SHIFT/PRESSURE TROUGH JUST EXITING SERN IA
WITH ACTUAL COLD FRONT FOLLOWING CLOSE BEHIND. GUSTY NW WINDS ARE
ANTICIPATED BEHIND THE FRONT TODAY WITH GUSTS OVER 30 KTS AT
TIMES. MID CLOUDS WILL EXIT SRN IA THIS MORNING FOLLOWED BY SCT-
BKN VFR CLOUDS DURING PEAK HEATING. OTHERWISE CLEAR SKIES ARE EXPECTED.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...
FROST ADVISORY 3 AM TO 9 AM CDT SUNDAY
AUDUBON-CALHOUN-CARROLL-CASS-CERRO GORDO-CRAWFORD-EMMET-GREENE-GUTHRIE-
HANCOCK-HUMBOLDT-KOSSUTH-PALO ALTO-POCAHONTAS-SAC-WEBSTER-WINNEBAGO-
WORTH-WRIGHT
&&
$$
SHORT TERM/AVIATION...SMALL
LONG TERM...JOHNSON
AREA FORECAST DISCUSSION
NWS GOODLAND KS
953 AM MDT SAT MAY 11 2013
.UPDATE...
ISSUED AT 947 AM MDT SAT MAY 11 2013
JUST COMPLETED A MINOR UPDATE...MAINLY FOR TEMPERATURES. CURRENT
TEMPERATURE TRENDS SUPPORT NEAR TO SLIGHTLY WARMER THAN CURRENT
FORECAST. HRRR AND RUC MATCHING UP WELL WITH REALITY AND SUPPORT
DOING THIS AS WELL. ADJUSTED ACCORDINGLY WITH MOST ADJUSTMENT IN
THE FAR SOUTHERN AND SOUTHWEST LOCATIONS.
ALSO PER CURRENT TRENDS AND NEWEST MODEL DATA THAT IS ROLLING
IN...ADJUSTED SKY COVER AND WINDS NOT ONLY FOR TODAY BUT ALSO INTO
TOMORROW. NEWEST MODEL DATA IS ALSO SUPPORTING CURRENT
PRECIPITATION FORECAST THROUGH TOMORROW AND INITIAL IMPRESSIONS
ARE THAT LITTLE IF ANY CHANGES WILL BE MADE TO THE CURRENT POP/WX
FORECAST.
&&
.SHORT TERM...(TODAY THROUGH MONDAY NIGHT)
ISSUED AT 200 AM MDT SAT MAY 11 2013
TODAY-TONIGHT...COLD FRONT CURRENTLY MOVING SOUTH ACROSS THE AREA.
SHOULD SEE SOME GUSTY NORTH TO NORTHEAST WINDS UP TO 25 MPH THIS
MORNING BEFORE SFC HIGH MOVES IN DECREASING WINDS RATHER QUICKLY
THIS AFTERNOON. WINDS BECOME SOUTH/SOUTHWESTERLY TONIGHT. A
WEATHER DISTURBANCE MOVES INTO FAR EASTERN COLORADO LATE THIS
AFTERNOON CONTINUING SOUTH/SOUTHEAST EARLY TONIGHT ACROSS THE FAR
SOUTHWEST AND WESTERN PARTS OF THE AREA. HAVE THUNDERSTORMS
MENTIONED IN THESE AREAS. AFTER MIDNIGHT THERE ARE DISCREPANCIES
IN WHETHER OR NOT ANOTHER WEAK DISTURBANCE MOVES ACROSS THE FAR
EASTERN ZONES...THE GFS HAS IT FURTHER EAST OUT OF THE AREA WHILE
THE NAM HAS IT GRAZING PARTS OF OUR AREA. CONSISTENCY THE PAST FEW
DAYS WOULD FAVOR THE NAM SOLUTION AND AS A RESULT HAVE KEPT SOME
SMALL POPS FOR THE EASTERN 1/3-1/4 OF THE AREA. HIGHS TODAY MID
60S TO AROUND 70. LOWS TONIGHT UPPER 30S NEAR FLAGLER WITH 40S
ELSEWHERE.
SUNDAY-SUNDAY NIGHT...MODELS CONTINUE TO HAVE DISCREPANCIES AS TO
WHETHER OR NOT WEATHER DISTURBANCES MOVE THROUGH THE NORTHWEST
FLOW ALOFT. GFS HAS ONE MOVE THROUGH DURING THE AFTERNOON WHILE
THE NAM DOES NOT. FOR NOW NO CHANGES PLANNED. UPPER RIDGE STARTS
TO MOVE IN DURING THE NIGHT SHUNTING ANY APPRECIABLE MOISTURE AND
CONVECTIVE THREAT EAST OF THE AREA. 850 TEMPERATURES WARM 12-14F
SUPPORTING HIGHS IN THE UPPER 70S TO LOW 80S WHICH IS ALSO
SUPPORTED BY BETTER PERFORMING BIAS CORRECTED GRIDS AND MAV/MET
GUIDANCE. NOT MUCH CHANGE NEEDED FROM PREVIOUS FORECAST. LOWS MID
40S TO LOW 50S.
MONDAY-MONDAY NIGHT...UPPER RIDGE CONTINUES TO SLOWLY MOVE EAST
TOWARD THE AREA. 850 TEMPERATURES WARM ANOTHER 8-13F FROM SUNDAYS
VALUES SUPPORTING HIGHS IN THE UPPER 80S WEST TO MID 90S EAST.
BIAS CORRECTED GRIDS AND MAV/MET GUIDANCE AVG A FEW DEGREES
COOLER. BLENDING THEM TOGETHER PRODUCES HIGHS IN THE MID TO UPPER
80S WEST...LOW TO MID 90S EAST. HAVENT GONE QUITE AS WARM AS 850
TEMPS SUPPORT ACROSS THE EASTERN 1/3 OF THE AREA FOR NOW BUT 96-97
DEGREES VERY POSSIBLE. THIS WOULD BREAK RECORD HIGHS FOR THE DATE
(SEE CLIMO SECTION BELOW). LOWS IN THE 50S.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 325 AM MDT SAT MAY 11 2013
MERIDIONAL FLOW BREAKS DOWN AS THE PERSISTENT RIDGE OVER THE WESTERN
UNITED STATES FLATTENS WITH A LOW CENTER MOVING EASTWARD ACROSS
SOUTHERN CANADA. THE COLD FRONT TRAILING BEHIND THAT LOW APPROACHES
THE CENTRAL HIGH PLAINS REGION ON TUESDAY AS A CUTOFF LOW THAT HAS
BEEN OVER NORTHERN MEXICO BEGINS TO LIFT OUT ACROSS THE SOUTHERN
PLAINS ON TUESDAY AND TUESDAY NIGHT. THE FRONT MOVES THROUGH THE
REGION EARLY WEDNESDAY WITH SHOWERS AND THUNDERSTORMS FORMING IN THE
VICINITY OF THE FRONT. THIS WILL BRING SOMEWHAT COOLER TEMPERATURES
TO THE REGION ON WEDNESDAY AND THURSDAY.
ZONAL FLOW BEGINS TO REAMPLIFY INTO A RIDGE OVER THE ROCKIES
THURSDAY AND FRIDAY AS THE NEXT UPPER TROUGH MOVES INTO THE WEST
COAST. TEMPERATURE ARE EXPECTED TO RISE THROUGH THE END OF THE WEEK
AND INTO THE WEEKEND WITH THE POSSIBILITY OF ISOLATED TO SCATTERED
SHOWERS AND THUNDERSTORMS EACH DAY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 200 AM MDT SAT MAY 11 2013
FOR KGLD...VFR EXPECTED THROUGH THE PERIOD. NORTH TO NORTHEAST
WINDS 10-15KTS AND GUSTY AT TAF ISSUANCE WILL BECOME LGT/VAR BY
00Z THEN VEER TO THE SOUTH THEN SOUTHWEST AT SPEEDS AROUND 10KTS
TONIGHT. NO PRECIPITATION EXPECTED AT THE TERMINAL BUT MAY SEE
SOME TCU/CB TO THE WEST/SOUTHWEST LATE THIS AFTERNOON THROUGH
EARLY TONIGHT.
FOR KMCK...VFR EXPECTED THROUGH THE PERIOD. NORTH WINDS AROUND
10KTS AT TAF ISSUANCE WILL DECREASE UNDER 5KTS BY VERY LATE IN THE
AFTERNOON THEN SHIFT TO THE SOUTHEAST AROUND 5KTS TONIGHT. THERE
IS A SMALL CHANCE FOR SHOWERS AND THUNDERSTORMS TO BE AROUND THE
TERMINAL AFTER 09Z.
&&
.CLIMATE...
ISSUED AT 200 AM MDT SAT MAY 11 2013
RECORD HIGH TEMPERATURES MONDAY:
HILL CITY....96 (1915)
MCCOOK.......95 (1962)
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...BULLER
SHORT TERM...99
LONG TERM...LOCKHART
AVIATION...99
AREA FORECAST DISCUSSION
NWS NEW ORLEANS LA
946 AM CDT SAT MAY 11 2013
.UPDATE...
GIVEN RECENT RADAR TRENDS...AND THE LATEST HRRR MODEL GUIDANCE
HAVE DECIDED TO LOWER RAIN CHANCES FOR MOST OF THE AREA TODAY.
EXPECT ONLY SCATTERED LIGHT RAIN SHOWERS AND AN ISOLATED
THUNDERSTORM TO IMPACT AREAS FROM THE INTERSTATE 10 CORRIDOR
NORTHWARD. ALONG THE LOUISIANA COAST...RAIN CHANCES WILL REMAIN
ELEVATED TODAY...WITH MORE NUMEROUS SHOWERS AND SCATTERED
THUNDERSTORMS ANTICIPATED. GIVEN THE ANTECDENT CONDITIONS IN PLACE
ACROSS THE SOUTHERN HALF OF THE FORECAST AREA...HAVE KEPT THE
FLASH FLOOD WATCH IN PLACE THROUGH TODAY FOR THESE AREAS.
HOWEVER...AREAS IN SOUTHWEST MISSISSIPPI AND NORTH OF INTERSTATE
12 HAVE BEEN REMOVED FROM THE WATCH GIVEN THE REDUCED THREAT FOR
HEAVY RAINFALL TODAY. HAVE ALSO MOVED UP THE EXPIRATION TIMES FOR
THE FLOOD WATCH IN THE REMAINING AREAS TO THIS EVENING AS THE
CONVECTION SHOULD BE WELL REMOVED FROM THE AREA BY THAT TIME. HAVE
ALSO COOLED DAYTIME HIGHS BACK INTO THE MIDDLE 70S DUE TO THE
ANTICIPATED CLOUD COVER AND RAINFALL ACTIVITY. 32
&&
.PREV DISCUSSION... /ISSUED 326 AM CDT SAT MAY 11 2013/
SHORT TERM...SEVERAL MORE ROUNDS OF SHOWERS AND THUNDERSTORMS
REMAIN BEFORE A SLOW MOVING COLD FRONT PUSHES OFFSHORE TONIGHT. AN
UPPER LEVEL TROUGH AXIS HAS A HOLD ON THE REGION. SEVERAL FAST MOVING
PERTURBATIONS MOVE ALONG THE AXIS PROVIDING THE INSTABILITY TO
KICK HEAVY RAIN. IR SATELLITE SHOWS 2 SUCH IMPULSES POISED TO MOVE
THROUGH. THE FIRST IS ASSOCIATED WITH THE RAIN INDICATED ON RADAR
IN SW LA AND THE OTHER FURTHER WEST IN S TX. EXPECT THE FIRST
IMPULSE TO BRING HEAVY RAIN THIS MORNING AND THE 2ND TO BRING
ANOTHER ROUND OF HEAVY RAIN LATER THIS MORNING ON INTO THE
AFTERNOON HOURS.
PREVIOUS SOUNDING MEASURED A PW OF 1.58 WITH VERY LITTLE TEMP DEW
POINT SPREADS THROUGH 35K FEET. GFS AND ECMWF HAVING SOME
DIFFICULTY HANDLING THE SITUATION...SEEMS MESO MODELS INITIALIZING
BETTER PER WSR88D. GFS HAS THE BULK OF THE RAIN FURTHER SOUTH THAN OTHER
MODEL SOLUTIONS. THE RUC SEEMS TO HAVE THE BEST HANDLE ON THIS
EVENT WITH A 850 THETA E RIDGE MOVING FROM NORTH FROM THE COAST.
EXPECT THE CONVECTION AND HEAVY RAIN TO FOLLOW THE THETA E AXIS.
MESO MODELS ALSO SHOW INCREASING UPPER LEVEL DIVERGENT FLOW WITH
SOME DEGREE OF SFC CONVERGENCE. THE THETA E AXIS... IMPULSE
INDUCED LIFT...UPPER LEVEL DIVERGENCE AND LOW LEVEL CONVERGENCE
ALL ADD UP TO THE POTENTIAL OF HEAVY RAIN. FFG VALUES AVERAGE OUT
TO BE AROUND 1.6 TO 2.1 INCHES AN HOUR FOR MOST LOCATIONS. HOWEVER...
SEVERAL LOCATIONS ARE AT PARTICULAR RISK WITH .5 INCHES FOR AN
HOUR AND EVEN .6 INCHES IN A 6 HOUR PERIOD. RAIN ALONG THE COASTAL
LA PARISHES SUCH AS TERREBONNE AND LAFOURCHE WILL CAUSE FLASH
FLOOD ISSUES EXPANDING TO OTHER AREAS TODAY. ROUND ONE WILL BEGIN
AROUND 10Z WITH ROUND TWO NEAR 17Z.
THE COLD FRONT WILL PUSH THROUGH TONIGHT AND WILL BRING COOLER AND
DRIER AIR INTO THE ENTIRE AREA.
LONG TERM...
WE HAVE A CHANCE TO DRY OUT SUNDAY THROUGH MID WEEK. AN UPPER
TROUGH DIGS INTO THE AREA WED NIGHT AND INTO THURSDAY BRINGING
RAIN CHANCES BACK INTO THE FORECAST. SO FAR... THIS SYSTEM DOES
NOT APPEAR TO BE AS MOIST AND PROLONGED AS THE PREVIOUS. LOOKS LIKE
DIURNAL CONVECTION IS POSSIBLE LATE IN THE WEEK.
MARINE...THE PRESSURE GRADIENT HAS WEAKENED SOME AS THE COLD FRONT
DRIFTS EVER CLOSER TO THE REGION. WEAK TO MODERATE ONSHORE FLOW WILL
GENERALLY CONTINUE THROUGH THE DAY BUT THE FRONT WILL FINALLY PUSH
INTO THE GULF OVERNIGHT AND WINDS WILL BECOME NRLY BEHIND IT.
MODERATE OFFSHORE WINDS ARE EXPECTED TOMORROW BUT AS HIGH PRESSURE
PUSHES INTO THE LOWER MS VALLEY THE PRESSURE GRADIENT WILL TIGHTEN
ACROSS THE NCNTRL AND NERN GULF AND THIS COULD LEAD TO STRONG
OFFSHORE WINDS OVERNIGHT SUN BEFORE FINALLY RELAXING MON AS HIGH
PRESSURE FINALLY SITS IN RIGHT OVER THE AREA. LGT WINDS ARE THEN
EXPECTED THROUGH THE MIDDLE OF THE WEEK AS HIGH PRESSURE DOMINATES
THE REGION. /CAB/
AVIATION...ALL SORTS OF AVIATION ISSUES THIS MORNING. MOST
TERMINALS ARE DEALING WITH CIG OR VSBY REDUCTIONS OR BOTH.
TERMINALS ARE RANGING FROM MVFR TO IFR WITH VSBYS GENERALLY B/T 2
AND 5SM AND CIGS FROM AS LOW AS 600 TO 5K FT. UNTIL CONVECTION MOVES
BACK IN NOT EXPECTING CONDITIONS TO CHANGE MUCH BESIDES BOUNCE
BETWEEN IFR AND MVFR...EVEN TEMPORARILY DROPPING TO LIFR AT TIMES.
CONVECTION SHOULD BEGIN TO IMPACT BTR B/T 915 & 945Z WITH EACH
TERMINAL TO THE EAST SEEING CONVECTION IN UNDER AND HOUR OR 2
AFTERWARD. CURRENT TIMING HAS MSY SEEING CONVECTION NEAR
1030-1045Z. OF COURSE CIGS AND VSBYS WILL BE REDUCED SIGNIFICANTLY
WITH THE CONVECTION AND FREQUENT LIGHTNING WILL BE AN ISSUE AGAIN.
WIND GUSTS WILL BE A PROBLEM BUT DO NOT APPEAR TO BE AS MUCH OF AN
ISSUE AS THEY WERE YESTERDAY. CONVECTION SHOULD FINALLY CLR OUT
AFTER 20Z. /CAB/
DECISION SUPPORT...
DSS CODE...YELLOW.
DEPLOYED...NONE.
ACTIVATION...NONE.
ACTIVITIES...SLURRY SUPPORT
MONITORING RIVERS
MONITORING CONVECTION FOR SEVERE AND FLASH FLOODING
DECISION SUPPORT SERVICES (DSS) CODE LEGEND
GREEN = NO WEATHER IMPACTS THAT REQUIRE ACTION
BLUE = LONG FUSED WATCH/WARNING/ADVISORY IN EFFECT OR HIGH
VISIBILITY EVENT
YELLOW = HEIGHTENED IMPACTS WITH SHORT FUSED
WATCH/WARNING/ADVISORY ISSUANCES; RADAR SUPPORT
ORANGE = HIGH IMPACTS - SLIGHT TO MODERATE RISK SEVERE; NEARBY
TROPICAL EVENTS; HAZMAT OR OTHER LARGE EPISODES
RED = FULL ENGAGEMENT FOR MODERATE TO HIGH RISK SVR
AND/OR DIRECT TROPICAL THREATS; EVENTS OF NATIONAL
SIGNIFICANCE
&&
.PRELIMINARY POINT TEMPS/POPS...
MCB 74 55 78 49 / 20 20 10 10
BTR 75 57 79 51 / 40 20 10 10
ASD 75 58 78 51 / 40 30 10 10
MSY 75 63 78 57 / 50 30 10 10
GPT 74 59 78 52 / 40 40 10 10
PQL 75 58 78 50 / 40 40 10 10
&&
.LIX WATCHES/WARNINGS/ADVISORIES...
LA...FLASH FLOOD WATCH UNTIL 7 PM SATURDAY FOR THE FOLLOWING ZONES:
ASCENSION...ASSUMPTION...EAST BATON
ROUGE...IBERVILLE...LIVINGSTON...ORLEANS...SOUTHERN
TANGIPAHOA...ST. CHARLES...ST. JAMES...ST. JOHN THE
BAPTIST...ST. TAMMANY...UPPER JEFFERSON...UPPER
LAFOURCHE...UPPER PLAQUEMINES...UPPER ST. BERNARD...UPPER
TERREBONNE...AND WEST BATON ROUGE.
GM...NONE.
MS...FLASH FLOOD WATCH UNTIL 7 PM SATURDAY FOR THE FOLLOWING ZONES:
HANCOCK...HARRISON...AND JACKSON.
GM...NONE.
&&
$$
32
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1112 AM EDT SAT MAY 11 2013
LATEST UPDATE...
UPDATE/MARINE
.SYNOPSIS...
ISSUED AT 334 AM EDT SAT MAY 11 2013
A COLD FRONT WILL MOVE THROUGH LOWER MICHIGAN TODAY BRINGING SHOWERS
WITH IT. COOLER WEATHER WILL FOLLOW FOR SUNDAY WITH WIDESPREAD FROST
EXPECTED SUNDAY NIGHT. A DRAMATIC WARM UP WILL DEVELOP EARLY NEXT
WEEK WITH HIGHS REACHING THE 80S MIDWEEK.
&&
.UPDATE...
ISSUED AT 1106 AM EDT SAT MAY 11 2013
NOTICED SOME LIGHTNING WITH THE CELL WEST OF LITTLE SABLE POINT.
BASED ON THIS I ADDED THUNDER TO THE FORECAST FOR SOUTHWEST MI
THIS AFTERNOON. THIS FRONT WILL MOVE QUICKLY THROUGH THE REGION
THIS AFTERNOON. BY 22Z IT SHOULD BE EAST OF LANSING. POPS WERE
ADJUSTED SLIGHTLY BECAUSE OF THE FASTER FRONTAL MOVEMENT.
&&
.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 334 AM EDT SAT MAY 11 2013
FORECAST CONCERNS DEAL WITH PCPN TRENDS TODAY AND FROST/FREEZE
CHANCES TONIGHT AND SUNDAY NIGHT.
LOW PRESSURE OVER WISCONSIN WILL DRAG A COLD FRONT ACROSS THE CWA
THIS AFTERNOON. REGIONAL RADAR SHOWS A BROKEN LINE OF SHOWERS MOVING
ACROSS THE UPPER MIDWEST. LOOK FOR THIS TO FILL IN A BIT BETTER THIS
AFTERNOON. WE DON/T EXPECTED TO MUCH RAIN WITH THIS AS MOISTURE IS
SOMEWHAT LIMITED. CAN/T RULE OUT THUNDER AS MUCAPES ARE IN THE
150-200 J/KG RANGE BUT OVERALL INSTABILITY IS ON THE LOW SIDE.
COLDER AIR WILL FLOW INTO THE CWA TONIGHT AND FROST IS POSSIBLE OVER
THE NRN 2 TIERS OF COUNTIES. COLD ADVECTION WILL CONTINUE SUNDAY AS
H8 TEMPS FALL TO -8C WHICH WILL YIELD LAKE DELTA T/S AROUND 13C.
SHOULD SEE SOME LAKE CLOUDS WITH THIS SETUP ALONG WITH A CHANCE OF
SHOWERS...SOME OF WHICH MAY BE MIXED WITH SNOW OVER THE NRN CWA.
AS THE UPPER TROUGH MOVES AWAY SUNDAY NIGHT SKIES SHOULD CLEAR AND
TEMPS WILL FALL INTO THE 20S/LWR 30S. WIDESPREAD FROST IS EXPECTED
WITH FREEZING TEMPS OVER MUCH OF THE CWA. A FREEZE WARNING MAY BE
NEEDED SUNDAY NIGHT.
.LONG TERM...(MONDAY NIGHT THROUGH FRIDAY)
ISSUED AT 334 AM EDT SAT MAY 11 2013
TYPICAL OF SPRING IN MICHIGAN OUR WARM THEN COLD THEN WARM AGAIN
WEATHER PATTERN WILL CONTINUE. MY ISSUE TODAY IS MOSTLY FOCUSED ON
WHAT HAPPENS TO THE FRONT THAT MOVES INTO THE AREA WEDNESDAY... DOES
IT STALL NEAR SOUTHWEST MICHIGAN PUTTING US BACK INTO A RAINY
PATTERN OR DOES IT SLIP FAR ENOUGH SOUTH TO DRY US OUT LATE THIS
COMING WEEK?
THE LARGE SCALE PATTERN CONTINUES TO FEATURE A HIGH AMPLITUDE UPPER
AIR PATTERN WITH CONSIDERABLE MERIDIONAL FLOW (WHY IT IS GETTING SO
COLD THIS WEEKEND). ALL OF THE OPERATIONAL MEDIUM RANGE MODELS
CONTINUE TO SUGGEST THIS PATTERN WILL FLATTEN OUT EARLY THIS COMING
WEEK. WE END UP WITH ONE OF THOSE EXTENDED EAST ASIAN JET FEATURES
BY MIDWEEK. TYPICALLY FOR SOUTHWEST MICHIGAN THAT MEANS WARMER THAN
NORMAL TEMPERATURES AND FREQUENT SHORTWAVES PRODUCING FREQUENT
PERIODS OF PRECIPITATION. ALL OF THIS HAS BEEN AND CONTINUES TO BE
THE MAIN ASPECT OF THE CHANGING UPPER AIR PATTERN. SO THE QUESTION
BECOMES... DOES THE FLATTER FLOW FORECAST BY THE ECMWF FROM
WEDNESDAY ON BECOME THE TRUE PATTERN OR WILL THE MORE AMPLIFIED
PATTERN OF THE GFS PREVAIL (THAT WOULD BE DRIER AND COOLER FOR
SOUTHWEST MICHIGAN)?
THERE ARE TWO CONCERNS OF MINE AS TOO WHY I QUESTION THE ECMWF THIS
TIME. FIRST IS THE SYSTEM MOVING ONTO THE WEST COAST CURRENTLY IS A
VERY DEEP TROUGH WITH A STRONG PACIFIC SYSTEM MOVING THROUGH THE
BASE OF THE TROUGH (JUST OFF THE OR/WA COAST). THE ECMWF FLATTENS
THIS WAVE AMAZINGLY FAST GIVEN ITS CURRENT AMPLITUDE. ALSO BOTH THE
ECMWF AND GFS SHOW A CLOSE UPPER HIGH DEVELOPING BY TUESDAY JUST
SOUTH OF GREENLAND. THAT THEN PERSISTS ON BOTH MODELS THROUGH THE
REST OF THE WEEK. OUR UPPER AIR FLOW WILL BE BLOCKED TO OUR EAST.
GIVEN THE BLOCKING TO THE EAST AND STRENGTH OF THE PACIFIC SYSTEM
MOVING ON SHORE (OUR WEDNESDAY SYSTEM) I WOULD HAVE TO FAVOR THE GFS
AT THIS POINT(MORE AMPLIFIED UPPER AIR PATTERN).
THE MORE AMPLIFIED PATTERN WOULD SUPPORT A STRONG COLD FRONT
WEDNESDAY EVENING WITH STRONGER THUNDERSTORMS BUT IT WOULD ALSO MEAN
A WARMER WEDNESDAY... THICKNESS VALUES AND 850 AND 925 MB TEMPS ARE
FORECAST TO BE AS WARM ENOUGH FOR LOWER TO MID 80S WEDNESDAY. SO I
HAVE TO IMAGINE EVEN WITH SOME FRONTAL CLOUDS AROUND MOST INLAND
AREAS SHOULD SEE HIGHS INTO THE LOWER 80S WEDNESDAY. WITH THAT MORE
AMPLIFIED PATTERN THE FRONT WOULD GO SOUTH OF MICHIGAN THURSDAY AND
IT WOULD COOL OFF SOME FOR THE REST OF THE WEEK.
IF THE ECMWF IS CORRECT... THE UPPER LOW OVER THE SW CONUS GETS
BOOTED EAST NORTHEAST TOWARD THE GREAT LAKES AND THAT BRING US A
STALLED FRONT WITH PERIODS OF SHOWERS AND THUNDERSTORMS WEDNESDAY
THROUGH FRIDAY (AND BEYOND).
FOR NOW I WILL SLIGHTLY FAVOR THE GFS AND KEEP POPS LOW WED THROUGH
FRIDAY. WE SHALL SEE HOW THIS PLAYS OUT.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 748 AM EDT SAT MAY 11 2013
IFR CIGS WILL LIFT TO MVFR WITH SHOWER BY MIDDAY THEN IMPROVE TO
SOLID VFR AND IT MAY EVEN CLEAR FOR A FEW HOURS LATE THIS
AFTERNOON. HOWEVER IT WILL BE WINDY FROM MID AFTERNOON INTO THE
EVENING BEHIND THE COLD FRONT.
AS THE PREVIOUS SHIFT EXPECTED THE LOW CLOUDS PERSISTED THROUGH
THE NIGHT INTO THE MID MORNING HOURS. CEILING DID COME DOWN FROM
MVFR TO IFR ACROSS THE TAF SITES. WITHIN THE LAST HOUR MKG WENT
DOWN TO LIFR WITH FOG.
I WOULD EXPECT THE MIXING AHEAD OF THE COLD FRONT IN CONJUNCTION
WITH DAY TIME HEATING... THE CEILING WILL AT LEAST IMPROVE TO MVFR
BY LATE MORNING. AT 1140Z THERE REMAINS A SOLID BAND OF SHOWERS
JUST AHEAD OF THE COLD FRONT OVER WISCONSIN. THEY WILL CROSS THE
GRR AREA BTW 16Z AND 19Z AND THE LAN AREA BETWEEN 19Z AND 22Z.
THERE IS MARGINALLY ENOUGH INSTABILITY FOR A FEW THUNDERSTORMS BUT
THEY SHOULD BE TO WIDELY SCATTERED TO PUT IN THE TAF FORECAST.
STRONG SUBSIDENCE BEHIND THE COLD FRONT WILL CLEAR SKIES LATE THIS
AFTERNOON AND INCREASE THE WIND SPEED TO 15 TO 25 MPH WITH HIGHER
GUSTS. WRAP AROUND MOISTURE WILL BRING LOW CLOUDS BACK AFTER
MIDNIGHT BUT I DID NOT PUT THEM IN THE CURRENT TAF EXCEPT FOR MKG
TO KEEP THE TAFS AS SIMPLE AS POSSIBLE.
&&
.MARINE...
ISSUED AT 1106 AM EDT SAT MAY 11 2013
STRONGER GUSTS TO GALE FORCE ASSOCIATED WITH THE COLD FRONT ARE
SHOWN ON THE HRRR RUC. FSL RUC HAD GUSTS OVER 30 KNOTS. STABILITY
OF THE LAKE MAY BE AN ISSUE...LIMITING THIS RISK. SO FAR THE HRRR
IS VERIFIY WELL WITH THE UPSTREAM GUSTS. WENT AHEAD AND ISSUED A
GALE WARNING. THE WINDS WILL BE SHIFTING SHARPLY...ADDING TO THE
HAZARD. BY 00Z A LULL IN THE WINDS IS FORECASTED...SO THE GALE
WARNING IS OF A SHORTER DURATION. MAY NEED TO EXTEND IT AS THE
WINDS WILL PICK BACK UP BY DAYBREAK SUNDAY.
&&
.FIRE WEATHER...
ISSUED AT 334 AM EDT SAT MAY 11 2013
SHOWERS ARE EXPECTED MAINLY THIS AFTERNOON. COOLER TEMPERATURES WILL
FOLLOW SUNDAY WITH HIGHS IN THE 40S.
&&
.HYDROLOGY...
ISSUED AT 334 AM EDT SAT MAY 11 2013
RAINFALL LESS THAN A QUARTER INCH TODAY WILL HAVE A NEGLIGIBLE
EFFECT ON RIVERS.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...GALE WARNING UNTIL 8 PM EDT THIS EVENING FOR LMZ844>849.
&&
$$
UPDATE...MJS
SYNOPSIS...93
SHORT TERM...93
LONG TERM...WDM
AVIATION...WDM
FIRE WEATHER...93
HYDROLOGY...93
MARINE...MJS
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
1025 AM EDT SAT MAY 11 2013
.SYNOPSIS...
CONVECTION WILL AFFECT THE AREA LATER TODAY AS A COLD FRONT
APPROACHES FROM THE WEST. THE FRONT WILL MOVE ACROSS THE FORECAST
AREA AND OFFSHORE DURING SUNDAY. COOLER AND DRIER CONDITIONS WILL
AFFECT THE FORECAST AREA MONDAY THROUGH WEDNESDAY AS COOL
CANADIAN HIGH PRESSURE TRACKS ACROSS THE REGION RESULTING WITH
TEMPERATURES RUNNING 5 TO 10 DEGREES BELOW NORMAL. A WARMING TREND
IS EXPECTED AT THE END OF THE WEEK ONCE THE HIGH MOVES OFFSHORE
FROM THE CAROLINA COASTS.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1030 AM SATURDAY...NOT THE MOST STRAIGHTFORWARD FORECAST IN
THE WORLD AT THIS POINT. SAT IMAGERY THIS MORNING SHOWS AMPLE BREAKS
IN THE CLOUDS AND MODERATE TO STRONG HEATING SHOULD GET UNDERWAY
TODAY. INSTABILITY NOT SO MUCH IN QUESTION WITH RESPECT TO
THUNDERSTORMS AS MUCH AS FORCING MECHANISM. CU FIELDS ALREADY
DEVELOPED OVER CAPE FEAR REGION AND HRRR SUGGESTS THAT ISO
CONVECTION MAY POP UP IN THIS VC BTW NOW AND 18Z...WHICH SEEMS
PLAUSIBLE ENOUGH. THERE SHOULD THEN BE A BREAK FOR A FEW HOURS AT
WHICH TIME ATTENTION TURNS TO OUR WEST. LATE AFTERNOON/EARLY EVENING
CONVECTION TO DEVELOP AND MOVE INTO THE REGION. LATEST SWODY1 FROM
SPC REDUCED SLIGHT RISK AREA CONSIDERABLY TAKING THE ENTIRE AREA
OUT. GIVEN THAT INSTABILITY LIKELY CAPPED AT 1000J PER KG AND SHEAR
MINIMAL THIS SEEMS FINE. WILL LEAVE FCST WORDING AS-IS WITH THE POSS
OF STRONG (SM HAIL AND GUSTY WINDS) BUT NOT SEVERE WORDING. LINE OF
STORMS MOVING IN FROM THE WEST LARGELY MISS SC COUNTIES ESP FURTHER
EAST INC GRAND STRAND AND MAY JUST MISS CAPE FEAR REGION TO THE N
AND W ALSO.
AS OF 630 AM SATURDAY...THE EVOLVING AND AMPLIFYING FULL LATITUDE
UPPER TROF OCCUPYING THE CENTRAL U.S. TODAY...AND THE EASTERN
THIRD OF THE U.S. BY DAYBREAK SUNDAY...WILL BE THE MAIN PLAYER
UPSTAIRS DURING THIS NEAR TERM PERIOD. FORTUNATELY THE SOUTHERN
STREAM CUT-OFF LOW OVER THE SW U.S. DOES NOT GET ABSORBED WITHIN
THE FLOW DURING THE EVOLUTION OF THIS UPPER TROF. WILL HAVE TO
CONTEND WITH ROTATING MID LEVEL VORTICIES/IMPULSES TRACKING ALONG
THE EAST SIDE OF THIS UPPER TROF AXIS. MODELS INDICATE THE
POSSIBILITY OF 1 TRACKING ACROSS THE CENTRAL CAROLINAS THIS
AFTERNOON AND EVENING...AIDING UPWARD FORCING IE. UVVS. DURING
THIS TIME PERIOD...A LEE SIDE...PRE-FRONTAL TROF...WILL HAVE
DEVELOPED ACROSS THE CENTRAL CAROLINAS AND SLOWLY TRACK TOWARDS
THE COAST THIS AFTERNOON AND EVENING. THE TIMING OF THIS UPPER
FEATURE AND ITS INTERACTION WITH THE SFC TROF COULD BE THE
DIFFERENCE FOR STRONG TO POSSIBLY SEVERE THUNDERSTORM ACTIVITY.
MODEL TIMING DIFFERENCES CONTINUE WITH THIS POSSIBLE INCREASED
POTENTIAL...IF IT OCCURS AT ALL. AT THIS POINT...WILL HIGHLIGHT
THE ISOLATED SEVERE IN THE HWO BUT MAINLY FOR THE INLAND COUNTIES.
SPC INDICATES LARGE HAIL AND DAMAGING WIND GUSTS THE PRIMARY
SEVERE THREATS. THE SFC BASED STABLE MARINE LAYER WILL BE CONFINED
BASICALLY TO THE COAST DUE TO THE STRONG SW-W WINDS JUST OFF THE
DECK PREVENTING ANY INLAND PROGRESSION OF THE SEA BREEZE.
SREF PROBS OF MEASURED PCPN CONTINUES THE GENERAL TREND FROM
YESTERDAY HIGHLIGHTING SPLIT PCPN MAXIMAS ASSOCIATED WITH THIS
CONVECTION. MEANING...THE ILM CWA REMAINS IN THE MIDDLE OR WITHIN
THE LOWEST PROBABILITY FOR MEASURED PCPN...IE. DRIER. WITH ALL THIS
SAID...HAVE SLIGHTLY LOWERED POPS TO 40 TO 60 PERCENT DURING THE
PEAK OF THIS AFTERNOON/EARLY EVENING CONVECTION. NAM AND GFS MOS
GUIDANCE REMAIN SIMILAR TO MAXES TODAY WITH MID 80S INLAND...UPPER
70S ALONG THE IMMEDIATE COAST PRIOR TO THE PINNED SEA BREEZE
DEVELOPMENT. HAVE STAYED CLOSER TO THE HIER SIDE OF MODEL MOS
GUIDANCE FOR TONIGHTS LOWS...DUE TO A SLOWER PROGRESSION OF THE
CFP ACROSS THE FA.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 3 AM SATURDAY...THE COLD FRONT WILL BE JUST INLAND AT THE
BEGINNING OF THE PERIOD AND WILL QUICKLY MOVE OFFSHORE DURING THE
MORNING HOURS. MAINTAINED THE INHERITED POPS WHICH SHOW GOOD
CHANCE ALONG THE COAST WITH MINIMUM VALUES INLAND. BY SUNDAY
AFTERNOON THE FRONT IS WELL OFFSHORE AND HAVE REMOVED POPS FROM
THE 0000-0600 UTC TIME FRAME. A TEMPERATURE FORECAST FROM THIS
POINT ON AS A SECONDARY SHORTWAVE THAT MOVES ACROSS MONDAY
AFTERNOON BRINGS ALONG THE BEST COLD AIR ADVECTION. THE MID
AFTERNOON ARRIVAL OF THE COLD AIR WILL ALLOW TEMPERATURES TO RISE
AT OR JUST ABOVE 70 MONDAY. TUESDAY MORNING LOWS REMAIN IN THE 40S
MODERATED BY A FEW KNOTS OF WIND REMAINING IN THE BOUNDARY LAYER.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
AS OF 3 AM SATURDAY...THE MID LEVEL PATTERN WILL QUICKLY CHANGE
FROM EAST COAST TROUGHING TO A QUASI ZONAL FLOW AS WEAK
SHORTWAVES WILL MOVE QUICKLY ACROSS THE CONUS. WPC GRAPHICS ARE
DOMINATED BY A PREFERENCE FOR THE ECMWF ENSEMBLE MEAN. ALL IS
QUIET UNTIL FRIDAY REGARDING POPS WHEN A WEAK SHORTWAVE WILL ALLOW
A PIEDMONT TROUGH TO DEVELOP AND MAINTAINED THE SLIGHT CHANCE
POPS. FORCING IS NEGLIGIBLE AS WOULD BE EXPECTED WITH THE LACK OF
MID LEVEL AMPLITUDE AND THIS SEEMS REASONABLE. TEMPERATURE TRENDS
REMAIN IN PLACE WITH A QUICK RECOVERY FROM BELOW NORMAL VALUES
EARLY TO SLIGHTLY ABOVE NUMBERS LATE.
&&
.AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...
AS OF 12Z...CONFIDENCE ONLY MODERATE THIS MORNING AS MODELS ARE NOT
IN AGREEMENT. WILL LEAN HEAVILY ON THE HRRR MODEL IN THE NEAR
TERM...WITH SCATTERED TO BROKEN CONVECTION DEVELOPING ALONG THE
COAST AND MOVING INTO THE MYRTLES ABOUT AN HOUR AFTER TAF TIME. ILM
STANDS THE BEST CHANCE FOR CONVECTION...WITH A RUMBLE OF THUNDER
POSSIBLE AFTER 16Z. VISIBILITIES WILL BE MVFR IN THE
SHOWERS...HOWEVER BRIEF PERIODS OF IFR ARE EXPECTED...LIKELY LASTING
15 MINUTES OR LESS AT A TIME. LOOK FOR A LULL IN THE ACTION...WITH
MORE CONVECTION FIRING MID TO LATE AFTERNOON OVER THE WESTERN
PORTION OF THE CWA IN ADVANCE OF A COLD FRONT. THIS CONVECTION IS
EXPECTED TO CONTINUE INTO THE EVENING HOURS...REACHING THE COAST BY
02-03Z.
EXTENDED OUTLOOK...LOW TO MODERATE CHANCE FOR CONVECTION DURING THE
PRE-DAWN SUNDAY HRS THROUGH MIDDAY SUNDAY DUE TO THE PASSAGE OF THE
COLD FRONT. MAY OBSERVE BRIEF IFR CONDITIONS. VFR CONDITIONS SUNDAY
AFTERNOON THRU WEDNESDAY DUE TO COOL CANADIAN HIGH PRESSURE.
&&
.MARINE...
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1030 AM SATURDAY...LITTLE TO NO CHANGES IN FORECAST THINKING
AT THIS TIME. SW GRADIENT WINDS TO INC SLIGHTLY POSSIBLY BOOSTING
SEAS HIGH ENOUGH TO WARRANT SCEC OVER NRN ZONE OR TWO.
AS OF 630 AM SATURDAY...A PRE-FRONTAL TROF WILL DEVELOP ACROSS THE
EAST CENTRAL CAROLINAS TODAY...AND MESH WITH THE APPROACHING COLD
FRONT TONIGHT. THIS FRONT WILL JUST REACH THE CAROLINA COASTS
AROUND DAYBREAK SUNDAY. THE SFC PRESSURE PATTERN AND TIGHTENING
GRADIENT AHEAD OF THE INLAND TROF WILL PRODUCE A SOLID SSW-SW WIND
AT 15 TO 20 KT...WITH A FEW GUSTS UP TO 25 KT POSSIBLE ACROSS THE
ILM NC WATERS. SIGNIFICANT SEAS WILL PRIMARILY BE A FUNCTION OF
THE 4 TO 6 SECOND PERIOD LOCALLY PRODUCED WIND DRIVEN WAVES.
THEREFORE...EXPECT A QUICK BUILDING OF THE SEAS BY THIS AFTERNOON
WITH 3 TO 5 FT ILM NC WATERS AND 3 TO 4 FT FOR THE ILM SC WATERS.
THE PROGGED AFTERNOON AND EVENING WIND AND SEAS COMBO FORECAST
WILL EXCEED SMALL CRAFT EXERCISE CAUTION THRESHOLDS FOR THE ILM NC
WATERS. WILL ISSUE THE SCEC FOR THE HOURS BETWEEN NOON TODAY
THROUGH 6 AM SUNDAY. A PINNED SEA BREEZE COULD PRODUCE A SLIGHT
BACKING OF THE WINDS NEAR SHORE TO S-SSW THIS AFTERNOON AND EARLY
EVENING. THE RELATIVELY COOLER NEAR SHORE WATERS...60S SSTS...WILL
HAVE A TREND TO WEAKEN THUNDERSTORMS THAT MOVE OFF THE MAINLAND
LATER TODAY. WILL HIGHLIGHT IN THE HWO FOR THE THREAT FOR 25 TO 35
KT WIND GUSTS FROM CONVECTION MOVING OFF THE MAINLAND.
.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 3 AM SATURDAY...A COLD FRONT WILL CROSS THE WATERS EARLY
SUNDAY WITH WINDS SHIFTING FROM SOUTHWEST TO NORTH. WIND SPEEDS WILL
REMAIN TEPID WITH THE WIND SHIFT...ON THE LOWE SIDE OF 10-15 KNOTS
UNTIL MONDAY WHEN A SECONDARY SHORTWAVE WITH DECENT COLD AIR
ADVECTION ARRIVES. SPEEDS AT THIS TIME WILL INCREASE BRIEFLY TO
15-20 KNOTS. BY TUESDAY MORNING...SPEEDS WILL LIKELY DROP A COUPLE
OF KNOTS. SIGNIFICANT SEAS WILL HOVER IN A 2-4 FOOT RANGE WITH THE
HIGHER VALUES MAINLY CONFINED TO THE OUTER WATERS.
.LONG TERM /TUESDAY THROUGH WEDNESDAY/...
AS OF 3 AM SATURDAY...HIGH PRESSURE WILL MOVE QUICKLY FROM THE
APPALACHIANS TO OFF THE SOUTHEAST COAST BY THE END OF THE PERIOD.
NORTHERLY WINDS WILL QUICKLY BACK TO A WEAK...LESS THAN TEN KNOTS...
SOUTHWESTERLY DIRECTION BY MIDDAY WEDNESDAY. THE DEVELOPMENT OF A
PIEDMONT TROUGH EARLY THURSDAY WHICH IS MORE INDICATIVE OF A MID
SUMMER PATTERN WILL INCREASE THE GRADIENT BACK TO THE HIGHER END OF
A 10-15 KNOT RANGE. SEAS WILL BE THE HIGHEST EARLY WITH SOME FOUR
FOOTERS ACROSS THE OUTER WATERS. HEIGHTS REALLY DIMINISH WEDNESDAY
BEFORE INCREASING ONCE AGAIN EARLY THURSDAY.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...DCH
NEAR TERM...MBB/DCH
SHORT TERM...SHK
LONG TERM...SHK
AVIATION...DL
MARINE...
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
645 AM EDT SAT MAY 11 2013
.SYNOPSIS...
CONVECTION WILL AFFECT THE AREA LATER TODAY AS A COLD FRONT
APPROACHES FROM THE WEST. THE FRONT WILL MOVE ACROSS THE FORECAST
AREA AND OFFSHORE DURING SUNDAY. COOLER AND DRIER CONDITIONS WILL
AFFECT THE FORECAST AREA MONDAY THROUGH WEDNESDAY AS COOL
CANADIAN HIGH PRESSURE TRACKS ACROSS THE REGION RESULTING WITH
TEMPERATURES RUNNING 5 TO 10 DEGREES BELOW NORMAL. A WARMING TREND
IS EXPECTED AT THE END OF THE WEEK ONCE THE HIGH MOVES OFFSHORE
FROM THE CAROLINA COASTS.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 630 AM SATURDAY...THE EVOLVING AND AMPLIFYING FULL LATITUDE
UPPER TROF OCCUPYING THE CENTRAL U.S. TODAY...AND THE EASTERN
THIRD OF THE U.S. BY DAYBREAK SUNDAY...WILL BE THE MAIN PLAYER
UPSTAIRS DURING THIS NEAR TERM PERIOD. FORTUNATELY THE SOUTHERN
STREAM CUT-OFF LOW OVER THE SW U.S. DOES NOT GET ABSORBED WITHIN
THE FLOW DURING THE EVOLUTION OF THIS UPPER TROF. WILL HAVE TO
CONTEND WITH ROTATING MID LEVEL VORTICIES/IMPULSES TRACKING ALONG
THE EAST SIDE OF THIS UPPER TROF AXIS. MODELS INDICATE THE
POSSIBILITY OF 1 TRACKING ACROSS THE CENTRAL CAROLINAS THIS
AFTERNOON AND EVENING...AIDING UPWARD FORCING IE. UVVS. DURING
THIS TIME PERIOD...A LEE SIDE...PRE-FRONTAL TROF...WILL HAVE
DEVELOPED ACROSS THE CENTRAL CAROLINAS AND SLOWLY TRACK TOWARDS
THE COAST THIS AFTERNOON AND EVENING. THE TIMING OF THIS UPPER
FEATURE AND ITS INTERACTION WITH THE SFC TROF COULD BE THE
DIFFERENCE FOR STRONG TO POSSIBLY SEVERE THUNDERSTORM ACTIVITY.
MODEL TIMING DIFFERENCES CONTINUE WITH THIS POSSIBLE INCREASED
POTENTIAL...IF IT OCCURS AT ALL. AT THIS POINT...WILL HIGHLIGHT
THE ISOLATED SEVERE IN THE HWO BUT MAINLY FOR THE INLAND COUNTIES.
SPC INDICATES LARGE HAIL AND DAMAGING WIND GUSTS THE PRIMARY
SEVERE THREATS. THE SFC BASED STABLE MARINE LAYER WILL BE CONFINED
BASICALLY TO THE COAST DUE TO THE STRONG SW-W WINDS JUST OFF THE
DECK PREVENTING ANY INLAND PROGRESSION OF THE SEA BREEZE.
SREF PROBS OF MEASURED PCPN CONTINUES THE GENERAL TREND FROM
YESTERDAY HIGHLIGHTING SPLIT PCPN MAXIMAS ASSOCIATED WITH THIS
CONVECTION. MEANING...THE ILM CWA REMAINS IN THE MIDDLE OR WITHIN
THE LOWEST PROBABILITY FOR MEASURED PCPN...IE. DRIER. WITH ALL THIS
SAID...HAVE SLIGHTLY LOWERED POPS TO 40 TO 60 PERCENT DURING THE
PEAK OF THIS AFTERNOON/EARLY EVENING CONVECTION. NAM AND GFS MOS
GUIDANCE REMAIN SIMILAR TO MAXES TODAY WITH MID 80S INLAND...UPPER
70S ALONG THE IMMEDIATE COAST PRIOR TO THE PINNED SEA BREEZE
DEVELOPMENT. HAVE STAYED CLOSER TO THE HIER SIDE OF MODEL MOS
GUIDANCE FOR TONIGHTS LOWS...DUE TO A SLOWER PROGRESSION OF THE
CFP ACROSS THE FA.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 3 AM SATURDAY...THE COLD FRONT WILL BE JUST INLAND AT THE
BEGINNING OF THE PERIOD AND WILL QUICKLY MOVE OFFSHORE DURING THE
MORNING HOURS. MAINTAINED THE INHERITED POPS WHICH SHOW GOOD
CHANCE ALONG THE COAST WITH MINIMUM VALUES INLAND. BY SUNDAY
AFTERNOON THE FRONT IS WELL OFFSHORE AND HAVE REMOVED POPS FROM
THE 0000-0600 UTC TIME FRAME. A TEMPERATURE FORECAST FROM THIS
POINT ON AS A SECONDARY SHORTWAVE THAT MOVES ACROSS MONDAY
AFTERNOON BRINGS ALONG THE BEST COLD AIR ADVECTION. THE MID
AFTERNOON ARRIVAL OF THE COLD AIR WILL ALLOW TEMPERATURES TO RISE
AT OR JUST ABOVE 70 MONDAY. TUESDAY MORNING LOWS REMAIN IN THE 40S
MODERATED BY A FEW KNOTS OF WIND REMAINING IN THE BOUNDARY LAYER.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
AS OF 3 AM SATURDAY...THE MID LEVEL PATTERN WILL QUICKLY CHANGE
FROM EAST COAST TROUGHING TO A QUASI ZONAL FLOW AS WEAK
SHORTWAVES WILL MOVE QUICKLY ACROSS THE CONUS. WPC GRAPHICS ARE
DOMINATED BY A PREFERENCE FOR THE ECMWF ENSEMBLE MEAN. ALL IS
QUIET UNTIL FRIDAY REGARDING POPS WHEN A WEAK SHORTWAVE WILL ALLOW
A PIEDMONT TROUGH TO DEVELOP AND MAINTAINED THE SLIGHT CHANCE
POPS. FORCING IS NEGLIGIBLE AS WOULD BE EXPECTED WITH THE LACK OF
MID LEVEL AMPLITUDE AND THIS SEEMS REASONABLE. TEMPERATURE TRENDS
REMAIN IN PLACE WITH A QUICK RECOVERY FROM BELOW NORMAL VALUES
EARLY TO SLIGHTLY ABOVE NUMBERS LATE.
&&
.AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...
AS OF 12Z...CONFIDENCE ONLY MODERATE THIS MORNING AS MODELS ARE NOT
IN AGREEMENT. WILL LEAN HEAVILY ON THE HRRR MODEL IN THE NEAR
TERM...WITH SCATTERED TO BROKEN CONVECTION DEVELOPING ALONG THE
COAST AND MOVING INTO THE MYRTLES ABOUT AN HOUR AFTER TAF TIME. ILM
STANDS THE BEST CHANCE FOR CONVECTION...WITH A RUMBLE OF THUNDER
POSSIBLE AFTER 16Z. VISIBILITIES WILL BE MVFR IN THE
SHOWERS...HOWEVER BRIEF PERIODS OF IFR ARE EXPECTED...LIKELY LASTING
15 MINUTES OR LESS AT A TIME. LOOK FOR A LULL IN THE ACTION...WITH
MORE CONVECTION FIRING MID TO LATE AFTERNOON OVER THE WESTERN
PORTION OF THE CWA IN ADVANCE OF A COLD FRONT. THIS CONVECTION IS
EXPECTED TO CONTINUE INTO THE EVENING HOURS...REACHING THE COAST BY
02-03Z.
EXTENDED OUTLOOK...LOW TO MODERATE CHANCE FOR CONVECTION DURING THE
PRE-DAWN SUNDAY HRS THROUGH MIDDAY SUNDAY DUE TO THE PASSAGE OF THE
COLD FRONT. MAY OBSERVE BRIEF IFR CONDITIONS. VFR CONDITIONS SUNDAY
AFTERNOON THRU WEDNESDAY DUE TO COOL CANADIAN HIGH PRESSURE.
&&
.MARINE...
.NEAR TERM /THROUGH TONIGHT/...
AS OF 630 AM SATURDAY...A PRE-FRONTAL TROF WILL DEVELOP ACROSS THE
EAST CENTRAL CAROLINAS TODAY...AND MESH WITH THE APPROACHING COLD
FRONT TONIGHT. THIS FRONT WILL JUST REACH THE CAROLINA COASTS
AROUND DAYBREAK SUNDAY. THE SFC PRESSURE PATTERN AND TIGHTENING
GRADIENT AHEAD OF THE INLAND TROF WILL PRODUCE A SOLID SSW-SW WIND
AT 15 TO 20 KT...WITH A FEW GUSTS UP TO 25 KT POSSIBLE ACROSS THE
ILM NC WATERS. SIGNIFICANT SEAS WILL PRIMARILY BE A FUNCTION OF
THE 4 TO 6 SECOND PERIOD LOCALLY PRODUCED WIND DRIVEN WAVES.
THEREFORE...EXPECT A QUICK BUILDING OF THE SEAS BY THIS AFTERNOON
WITH 3 TO 5 FT ILM NC WATERS AND 3 TO 4 FT FOR THE ILM SC WATERS.
THE PROGGED AFTERNOON AND EVENING WIND AND SEAS COMBO FORECAST
WILL EXCEED SMALL CRAFT EXERCISE CAUTION THRESHOLDS FOR THE ILM NC
WATERS. WILL ISSUE THE SCEC FOR THE HOURS BETWEEN NOON TODAY
THROUGH 6 AM SUNDAY. A PINNED SEA BREEZE COULD PRODUCE A SLIGHT
BACKING OF THE WINDS NEAR SHORE TO S-SSW THIS AFTERNOON AND EARLY
EVENING. THE RELATIVELY COOLER NEAR SHORE WATERS...60S SSTS...WILL
HAVE A TREND TO WEAKEN THUNDERSTORMS THAT MOVE OFF THE MAINLAND
LATER TODAY. WILL HIGHLIGHT IN THE HWO FOR THE THREAT FOR 25 TO 35
KT WIND GUSTS FROM CONVECTION MOVING OFF THE MAINLAND.
.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 3 AM SATURDAY...A COLD FRONT WILL CROSS THE WATERS EARLY SUNDAY
WITH WINDS SHIFTING FROM SOUTHWEST TO NORTH. WIND SPEEDS WILL
REMAIN TEPID WITH THE WIND SHIFT...ON THE LOWE SIDE OF 10-15 KNOTS
UNTIL MONDAY WHEN A SECONDARY SHORTWAVE WITH DECENT COLD AIR
ADVECTION ARRIVES. SPEEDS AT THIS TIME WILL INCREASE BRIEFLY TO
15-20 KNOTS. BY TUESDAY MORNING...SPEEDS WILL LIKELY DROP A COUPLE
OF KNOTS. SIGNIFICANT SEAS WILL HOVER IN A 2-4 FOOT RANGE WITH THE
HIGHER VALUES MAINLY CONFINED TO THE OUTER WATERS.
.LONG TERM /TUESDAY THROUGH WEDNESDAY/...
AS OF 3 AM SATURDAY...HIGH PRESSURE WILL MOVE QUICKLY FROM THE
APPALACHIANS TO OFF THE SOUTHEAST COAST BY THE END OF THE PERIOD.
NORTHERLY WINDS WILL QUICKLY BACK TO A WEAK...LESS THAN TEN KNOTS...
SOUTHWESTERLY DIRECTION BY MIDDAY WEDNESDAY. THE DEVELOPMENT OF A
PIEDMONT TROUGH EARLY THURSDAY WHICH IS MORE INDICATIVE OF A MID
SUMMER PATTERN WILL INCREASE THE GRADIENT BACK TO THE HIGHER END OF
A 10-15 KNOT RANGE. SEAS WILL BE THE HIGHEST EARLY WITH SOME FOUR
FOOTERS ACROSS THE OUTER WATERS. HEIGHTS REALLY DIMINISH WEDNESDAY
BEFORE INCREASING ONCE AGAIN EARLY THURSDAY.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...DCH
NEAR TERM...DCH
SHORT TERM...SHK
LONG TERM...SHK
AVIATION...DL
MARINE...
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
759 AM EDT SAT MAY 11 2013
.SYNOPSIS...
A COLD FRONT WILL CONTINUE TO MOVE EAST AND OUT OF THE OHIO VALLEY
THIS MORNING. AN UPPER LEVEL LOW AND A WEAK SECONDARY COLD FRONT
WILL CROSS THE REGION THIS AFTERNOON AND EARLY EVENING...SPARKING
SOME SHOWER ACTIVITY. AFTER THIS...HIGH PRESSURE WILL BUILD IN THE
MID SECTION OF THE COUNTRY WITH DRIER AND COOLER AIR CONTINUING TO
FILTER INTO THE OHIO VALLEY ON NORTHERLY WINDS.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
QUICK EARLY MORNING UPDATE JUST SENT. NEEDED TO ACCOUNT FOR RATHER
DECENT COVERAGE OF -DZ THIS MORNING - NOT SHOWING UP SO MUCH IN
ASOS/AWOS DATA - BUT CLEARLY SEEN BY LONG PULSE/SENSITIVE VCP 31
KILN RADAR SWEEPS AND TDWR DATA ACROSS THE AREA. THIS SHOULD
CONTINUE THROUGH THE MORNING BUT AS CEILINGS LIFT JUST A BIT
SHOULD BECOME MORE AND MORE LIMITED TOWARD AFTERNOON. MADE A
RATHER SIGNIFICANT ADJUSTMENT TO TEMPS. LATEST 09Z HRRR AND 10Z
RAP...AS WELL AS 11.06Z RUNS OF NAM WRF AND GFS ALL SHOWING WEAK
CAA TO CONTINUE COINCIDENT WITH EXPANSIVE STRATUS. ALL THESE DATA
SHOW MINIMUM POOL OF SFC-900MB TEMPS ACROSS I-71 CORRIDOR INTO
AFTN AND THUS THIS SHOULD AFFECT TEMPS - SO PULLED BACK QUITE A
BIT - MUCH TOWARD 11.00Z MET MOS VALUES WHICH SEEM A LOW OUTLIER
BUT PROBABLY CLOSER TO REALITY. FEAST OR FAMINE THIS TIME OF
YEAR...AN EXTRA HOUR OR TWO OF SUN WILL BOOST TEMPS...SO WATCHING
SKY COVER CLOSELY TODAY. COLD FRONT/SHRA RIGHT NOW JUST PUSHING
THRU MADISON/QUAD CITIES AND WILL BE HERE LATER THIS AFTN/EVE.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH MONDAY/...
ANY RAIN WITH THE SECONDARY FRONT WILL BE FINISHED EARLY IN THE
EVENING AND CONTINUED WEST-NORTHWEST FLOW WILL HELP USHER IN
OVERNIGHT LOW TEMPERATURES IN THE MID TO UPPER 30S. DO NOT BELIEVE
THAT THERE IS A THREAT FOR FROST AS WIND SPEEDS WILL BE 10 MPH OR
SO AND TEMPERATURES WILL NOT BE COLD ENOUGH FOR A FREEZE.
THE COLD AIR WILL CONTINUE TO BE PULLED INTO THE REGION ON SUNDAY
AND HIGHS SHOULD BE 5 DEG COOLER ON AVERAGE THAN WHAT OCCURS
TODAY. AM SLIGHTLY CONCERNED ABOUT SOME INCREASE IN CLOUDS ALONG
THE OHIO RIVER SUNDAY NIGHT. WHILE THE SETTLING HIGH PRESSURE
SYSTEM AND COOL AIR WILL RESULT IN A NICE RADIATIONAL COOLING
SETUP OVER THE REGION...OPERATIONAL MODELS ARE ALL HINTING AT A
LITTLE MAXIMA OF MOISTURE CUTTING FROM EAST CENTRAL INDIANA INTO
SOUTHWEST OHIO AND NORTHEAST KENTUCKY. THIS COULD LIMIT ANY FROST
POTENTIAL TOMORROW NIGHT/MONDAY MORNING IN THIS AREA. FROST
REMAINS A STRONG POSSIBILITY OVER CENTRAL OHIO DURING THIS TIME
HOWEVER.
TEMPERATURES WILL BEGIN TO REBOUND ON MONDAY AS THE HIGH SETTLES
EAST OF THE REGION AND RETURN FLOW CAN SET UP UNDER A RELATIVELY
CLEAR SKY COVER DURING THE DAY.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
FCST PERIOD BEGINS WITH HIGH PRESSURE BUILDING IN WITH CAA PROVIDING
BELOW NORMAL TEMPERATURES THROUGH MONDAY. STILL EXPECTING NEAR
RECORD LOWS FOR SUNDAY NIGHT WITH FROST POTENTIAL. MODELS HINTING AT
A LITTLE MOISTURE OFF THE LAKE ENOUGH TO PRODUCE SOME CLOUDS LATE
SUNDAY NIGHT WHICH MAY KEEP TEMPS FROM REACHING RECORD VALUES. WAA
SETS UP FOR MONDAY NIGHT/TUESDAY. MODELS ARE INDICATING INCREASING
MOISTURE AND HAVE PUT IN A SMALL POP FOR NOW. THIS MAY HAVE TO BE
INCREASED IF TRENDS CONTINUE. TEMPS WILL BE SLOWER TO REBOUND
BECAUSE OF CLOUDS AND POSSIBLE SHOWERS. WILL TREND DOWNWARD BUT NOT
AS LOW AS GUIDANCE FOR NOW. SHOULD SEE DRY DAY FOR WEDNESDAY WITH
STRONG HEATING. HAVE BUMPED UP TEMPS CLOSE TO GUIDANCE. MODELS NOT
COMPLETELY IN AGREEMENT FOR SYSTEM FOR WEDNESDAY NIGHT AND THURSDAY.
ECMWF KEEPS FRONT TO THE NORTH WHILE OTHER MODELS BRING FRONT INTO
OHIO VALLEY REGION WITH SHOWERS AND STORMS FOR WEDNESDAY NIGHT AND
THURSDAY. HAVE KEPT POPS IN FOR THIS SCENARIO BUT REMAINING LOW WITH
UNCERTAINTY. COOLER TEMPS FOR THURSDAY BUT MAY NOT BE AS COOL IF
ECMWF MODEL IS CORRECT. SYSTEM LINGERS IN THE AREA THROUGH FRIDAY
AND HAVE CONTINUED LOW POPS IN UNTIL MORE CERTAIN OF MODEL
CONSISTENCY.
&&
.AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...
MVFR TO IFR CEILINGS WILL CONTINUE ACROSS THE AREA THIS MORNING.
WEAK HIGH PRESSURE BRIEFLY NOSING INTO THE REGION TODAY SHOULD
RESULT IN SOME GRADUAL IMPROVEMENT IN THE CEILINGS BY MIDDAY...BUT
EXPECT MVFR CEILINGS FOR MOST OF THE DAY. WINDS WILL SHIFT BACK TO
THE WEST EARLY THIS AFTERNOON AHEAD OF ANOTHER COLD FRONT APPROACHING
FROM THE NW. THAT FRONT WILL BRING ANOTHER CHANCE OF SHOWERS AS IT
CROSSES THE REGION LATE THIS AFTERNOON AND EVENING. EXPECT THE
SHOWERS TO QUICKLY MOVE OUT OF THE AREA BY AROUND 04Z SUNDAY.
CONTINUING WITH VCSH MENTION IN THE TAFS FOR NOW. EXPECT BREEZY
CONDITIONS FOR A TIME THIS EVENING AS THE FRONT MOVES THROUGH...
OTHERWISE VFR CONDITIONS EXPECTED FOR THE REMAINDER OF THE TAF
PERIOD.
OUTLOOK...NO SIGNIFICANT WEATHER IS EXPECTED.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...FRANKS
NEAR TERM...BINAU
SHORT TERM...FRANKS
LONG TERM...PADGETT
AVIATION...KURZ
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
557 AM CDT SAT MAY 11 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 343 AM CDT SAT MAY 11 2013
MAIN FORECAST CONCERNS ARE ON WINDS TODAY...AND IF FROST OR FREEZE
CONDITIONS CAN OCCUR TONIGHT.
CURRENTLY AS OF 08Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS
SHOWED STRONG RIDGING ALONG THE WEST COAST OF NORTH AMERICA AND A
SHARP/POTENT UPPER TROUGH DROPPING INTO NORTHERN MINNESOTA AND
NORTHWEST ONTARIO. A NARROW BAND OF SHOWERS CONTINUE ON RADAR
IMMEDIATELY AHEAD OF THE UPPER TROUGH...RESULTING FROM STRONG DPVA
AS WELL AS LOW LEVEL FRONTOGENETIC FORCING BEHIND A COLD FRONT. THIS
COLD FRONT EXTENDED FROM CENTRAL LAKE SUPERIOR TO WINONA MN AND DES
MOINES IA. PLENTY OF DRY AIR EXISTS BOTH AHEAD AND BEHIND THE COLD
FRONT...NOTED BY 00Z SOUNDINGS FROM MPX AND BIS. THE 00Z INL
SOUNDING WAS MOST REPRESENTATIVE OF THE ENVIRONMENT WITH THE NARROW
BAND OF SHOWERS...REFLECTING HIGH CLOUD BASES AND SATURATION MAINLY
FROM 750-550MB. THE HIGH CLOUD BASES COMBINED WITH THE LACK OF
MOISTURE KEEPING RAINFALL AMOUNTS VERY LOW WITH THE BAND OF SHOWERS.
AS EXPECTED WITH A HIGHLY AMPLIFIED UPPER TROUGH...A STRONG PRESSURE
RISE OF ALMOST 2 MB /1 HR WAS PRESENT BEHIND THE FRONT. THIS
PRESSURE RISE HAS RESULTED IN GUSTS OF 25-35 KT IMMEDIATELY AFTER
THE FRONTAL PASSAGE. A TIGHT PRESSURE GRADIENT EXISTS TOO BEHIND THE
FRONT...AHEAD OF CANADIAN HIGH PRESSURE IN SASKATCHEWAN. THE
BLUSTERY NORTHWEST WINDS ARE BRINGING UNSEASONABLY COOL AIR
SOUTHEAST...WITH 850MB TEMPS AT 00Z OF -5C AT THE PAS MANITOBA.
THE POTENT UPPER TROUGH APPROACHING THE FORECAST AREA IS PROGGED TO
ENCOMPASS MUCH OF THE WESTERN GREAT LAKES REGION BY THIS
EVENING...THEN BEGIN A SLOW MARCH EAST. THIS UPPER TROUGH WILL LEAD
TO A VARIETY OF CONCERNS FOR THE SHORT TERM PERIOD.
1. WINDS. AFTER THE COLD FRONT PASSES THROUGH THE REST OF THE
FORECAST AREA EARLY THIS MORNING...A TIGHT PRESSURE GRADIENT IS
PROGGED TO REMAIN IN PLACE PRETTY MUCH THROUGH TONIGHT. THE SURFACE
HIGH SEEN IN SASKATCHEWAN STAYS OFF WELL TO THE WEST...DROPPING DOWN
INTO SOUTHWEST MN BY 12Z SUNDAY. DEEP MIXING COMBINED WITH COLD
ADVECTION...A UNIDIRECTIONAL NORTHWEST FLOW AND STRONG SUBSIDENCE
FROM THE UPPER TROUGH CROSSING WILL RESULT IN A WINDY DAY TODAY.
WINDS AT THE TOP OF THE MIXED LAYER...AROUND 775MB...ONLY TOP OUT
AROUND 40 KT. MIXING THIS DOWN RESULTS IN MAX GUSTS IN THE 30-35 KT
RANGE...BELOW ADVISORY CRITERIA. WINDS ARE LIKELY TO DIMINISH THIS
EVENING WITH LOSS OF DAYTIME HEATING...BUT THERE IS NO CHANCE TO
DECOUPLE TONIGHT.
2. TEMPERATURES. 850MB TEMPS ARE PROGGED TO COOL TO AROUND -2C BY
18Z...OR 1.5-2 STANDARD DEVIATIONS BELOW NORMAL. AS MENTIONED IN THE
WINDS...THE STRONG MAY SUN WILL EASILY ALLOW MIXING UP TO 850MB AND
BEYOND...WHICH YIELDS HIGHS MAINLY IN THE LOW TO MID 50S. COLD
ADVECTION CONTINUES INTO TONIGHT AS 850MB TEMPS PLUNGE TO -4 TO -6C.
THE QUESTION IS IF THE WINDS MAY KEEP THE BOUNDARY LAYER MIXED
ENOUGH TO PREVENT TEMPERATURES FROM FALLING MUCH BELOW FREEZING. THE
11.00Z REGIONAL CANADIAN...ECMWF AND HIRES ARW KEEPS TEMPERATURES AT
OR ABOVE FREEZING ACROSS THE FORECAST AREA...WHEREAS THE 11.00Z NAM
HAS READINGS MORE IN THE 25 TO 30 RANGE. MOS GUIDANCE AND THE 11.00Z
GFS SPLIT THE DIFFERENCE AND KEEPS THE COLDEST TEMPERATURES OVER
CENTRAL WISCONSIN. TYPICALLY THE REGIONAL CANADIAN IS COLD FOR
LOWS...SO IT IS SURPRISING TO SEE IT BEING ONE OF THE WARMER MODELS.
GIVEN THE WIND...HAVE LEANED MORE TOWARDS THE 11.00Z GFS/HIRES ARW
AND REGIONAL CANADIAN IDEA. UPSTREAM OVER NORTH DAKOTA...
TEMPERATURES ARE STILL MOSTLY ABOVE FREEZING AS WELL AS OF 08Z.
3. FROST/FREEZE TONIGHT. VERY TRICKY AS NOTED BY THE TEMPERATURE
DISCUSSION ABOVE. WITH THE WIND AND DRY AIR ADVECTION TAKING PLACE
THROUGH TONIGHT...SEEMS HARD TO GET MUCH FROST DEVELOPMENT UNLESS
YOU ARE IN A REALLY SHELTERED LOCATION FROM THE NORTHWEST WIND.
RELATIVE HUMIDITIES LOOK TO STRUGGLE TO RISE TO 75 PERCENT. IN
ADDITION...WITH THE CONCERN ABOUT TEMPERATURES NOT FALLING BELOW
FREEZING...MAY NOT SEE FREEZE CONDITIONS EXCEPT PERHAPS IN TAYLOR
COUNTY. EVEN IF WE SEE FREEZE CONDITIONS...THEY MAY ONLY LAST AN
HOUR. THUS...HAVE NOT ISSUED ANY FROST/FREEZE HEADLINES FOR TONIGHT.
4. PRECIPITATION. ONGOING SHOWERS SHOULD PUSH SOUTHEAST OF THE AREA
BY 12Z THIS MORNING. UPSTREAM...THERE IS A CLUSTER OF CLOUDS ALONG
WITH A FEW SHOWERS AROUND THE GRAND FORKS AND FARGO AREAS OF NORTH
DAKOTA. THESE ARE ASSOCIATED WITH A SHORTWAVE WITHIN THE TROUGH.
GOOD MODEL AGREEMENT EXISTS OF THE SHORTWAVE AND CLOUDS DROPPING
THROUGH SOUTHERN MN AND NORTHERN IA TODAY. HAVE INCLUDED A FEW
SPRINKLES AS WELL AS THERE IS CONCERN THE SHOWERS MAY DRY UP SOME AS
HRRR RUNS SUGGEST. A FEW OTHER DIURNALLY DRIVEN SHOWERS/SPRINKLES
ASSOCIATED WITH THE COLD POOL MAY FORM TOO ACROSS TAYLOR/CLARK
COUNTIES.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 343 AM CDT SAT MAY 11 2013
SUNDAY THROUGH MONDAY NIGHT...THE UPPER RIDGE THAT HAS BEEN BUILDING
UP ALONG THE WEST COAT OF THE U.S. IS PROGGED BY ALL MODELS TO GET
PUSHED EAST DURING THIS PERIOD...IN RESPONSE TO A STRONG SHORTWAVE
COMING INTO THE PACIFIC NORTHWEST LATE MONDAY. THIS UPPER RIDGE WILL
HELP TO KEEP THIS PERIOD OF UNSEASONABLY COOL AIR BRIEF. BY LATE
SUNDAY NIGHT...WESTERN PORTIONS OF THE FORECAST AREA SHOULD START
GETTING INTO THE WARM ADVECTION SETUP. UNTIL THEN...MAIN CONCERN IS
FROST/FREEZE SUNDAY NIGHT. MODELS PROG THE SURFACE CANADIAN HIGH
PRESSURE RIDGE TO BE CENTERED OVER THE ENTIRE FORECAST AREA AT 06Z
MONDAY...LEADING TO CLEAR SKIES AND LIGHT WINDS. GIVEN A COOL SUNDAY
TO BEGIN WITH...SITUATION SHOULD BE VERY FAVORABLE FOR FROST/FREEZE
CONDITIONS ACROSS MUCH OF THE FORECAST AREA...ESPECIALLY OVER
WISCONSIN. LEANED TOWARDS THE COOLER SIDE OF GUIDANCE FOR LOWS...
RESULTING IN THE NEED FOR A FREEZE WATCH FOR COUNTIES ALONG AND
NORTHEAST OF I-94. THE WARM ADVECTION MONDAY INTO MONDAY NIGHT IS
INTERESTING AS 850MB TEMPS CLIMB ABOUT 12C FROM 12Z MONDAY TO 12Z
TUESDAY. GOOD MODEL AGREEMENT EXISTS THAT AN AREA OF MID AND HIGH
CLOUDS WILL DEVELOP IN RESPONSE TO THIS WARM ADVECTION. ISENTROPIC
LIFT FIELDS ON THE 295 AND 300K SURFACE SHOW AN AREA OF LIFT
OCCURRING WITHIN THESE CLOUDS...MARCHING EAST WITH TIME. THE 11.00Z
GFS/ECMWF AND 11.03Z SREF ALL DEVELOP PRECIPITATION...WHILE THE
11.00Z NAM IS DRY. THE NAM DOES NOT DEVELOP PRECIPITATION BECAUSE OF
DRY LOW LEVELS ABSORBING THE RAIN...WHICH THE NAM TENDS TO OVERDO.
THUS...HAVE KEPT AND RAISED SLIGHTLY THE PRECIPITATION CHANCES FOR
MONDAY AFTERNOON AND EVENING. DID TAKE OUT THE THUNDER...THOUGH...AS
NO INSTABILITY EXISTS.
FOR THE REST OF THE WEEK...
FOCUS REMAINS ON HIGH TEMPERATURES ON TUESDAY. 11.00Z CANADIAN AND
ECMWF HAVE WENT BACK AND NOW SHOW A SURFACE WARM FRONT PROGRESSING
THROUGH THE AREA QUICKER...WHICH ALLOWS WARMER AIR TO PUSH INTO THE
AREA DURING THE DAY. THE 11.00Z GFS HAS STAYED PERSISTENT. ALL
MODELS NOW SHOW 850MB TEMPS CLIMBING TO 18C OVER CENTRAL WISCONSIN
TO 24C NEAR I-35 BY 00Z...WHICH ARE 2.5 STANDARD DEVIATIONS ABOVE
NORMAL. ONCE YOU GET TO 2.5...CONCERN INCREASES OF REACHING RECORDS.
PROBLEM IS MOST MODEL GUIDANCE HAS TOO MUCH MOISTURE IN THE BOUNDARY
LAYER. THE SCENARIO IS THE GULF OF MEXICO IS CUT OFF BY THE CURRENT
CANADIAN HIGH DROPPING DOWN TO THE GULF COAST...AND CROPS THAT ARE
BEHIND SCHEDULE DUE TO THE COOL SPRING. MODELS ARE TRYING TO GET THE
MOISTURE FROM EVAPOTRANSPORATION. WITH TOO MUCH MOISTURE IN THE
BOUNDARY LAYER...TEMPERATURES CANNOT RISE ENOUGH FROM MIXING.
THUS...HAVE STAYED PRETTY CLOSE TO THE PREVIOUS FORECAST AND BOOSTED
READINGS A FEW DEGREES WEST OF THE MISSISSIPPI RIVER TO ACCOUNT FOR
THE GROWING CONSENSUS ON THE WARM AIR TIMING. TEMPERATURES MAY STILL
NEED TO BE RAISED FURTHER.
A COLD FRONT ACCOMPANYING THAT TROUGH COMING INTO THE PACIFIC
NORTHWEST MONDAY IS SLATED TO COME THROUGH THE FORECAST AREA TUESDAY
NIGHT AND WEDNESDAY. FOLLOWED A CONSENSUS BLEND AND HAVE JUST LOW
CHANCES FOR SHOWERS/STORMS AS THE FRONT MOVES THROUGH. BEYOND
WEDNESDAY...THE FORECAST GETS MUDDLED WITH THE 11.00Z ECMWF/CANADIAN
SUGGESTING MORE OF A ZONAL TO SLIGHT UPPER RIDGING PATTERN IN PLACE
AS TROUGHING REFORMS IN THE PACIFIC NORTHWEST. MEANWHILE...THE
11.00Z GFS/GFS ENSEMBLES DEPICT TROUGHING TO FORM AND LINGER AROUND
THE FORECAST AREA. BOTH SITUATIONS SUGGEST A TREND TOWARDS
DRIER...AND THEREFORE THE CHANCES OF PRECIPITATION HAVE BEEN LOWERED
SOME. COULD SEE FINE TUNING TAKING PLACE TO DRY OUT PORTIONS OF THE
WEDNESDAY NIGHT THROUGH FRIDAY PERIOD. OTHERWISE...TEMPERATURES LOOK
COOLER BUT SHOULD STILL STAY NEAR OR ABOVE NORMAL WITH A MOSTLY
PACIFIC FLOW OF AIR.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 556 AM CDT SAT MAY 11 2013
MAIN CONCERN WILL BE GUSTY POST-COLD FRONTAL NORTHWEST WINDS TODAY
INTO EARLY THIS EVENING. PLAN ON SUSTAINED WINDS IN THE 20-25KT
RANGE WITH GUSTS AROUND 35KT. LOOK FOR THESE WINDS TO SUBSIDE TO
10KT OR LESS AFTER 03Z THIS EVENING. OTHERWISE...SCT-BKN CUMULUS
EXPECTED TODAY WITH BASES AOA 4KFT. LOOK FOR THESE CLOUDS TO
DISSIPATE ALSO WITH SUNSET...WITH SKIES BECOMING CLEAR THROUGH THE
OVERNIGHT HOURS.
&&
.FIRE WEATHER...
ISSUED AT 343 AM CDT SAT MAY 11 2013
BREEZY NORTHWEST WINDS ARE EXPECTED THIS WEEKEND AHEAD OF A
STRONG AREA OF CANADIAN HIGH PRESSURE OVER SASKATCHEWAN DROPPING
SOUTHEASTWARD. THESE NORTHWEST WINDS ARE GOING TO USHER IN AN
UNSEASONABLY COOL AND DRY AIRMASS INTO THE FORECAST AREA. DEEP
MIXING RESULTING FROM THE STRONG MAY SUN SHOULD ALLOW DEWPOINTS TO
DROP INTO THE MID TEENS TO MID 20S DURING THE AFTERNOON...WHICH
WITH HIGH TEMPERATURES IN THE LOW TO MID 50S...RELATIVE HUMIDITIES
WILL DROP TO 20 TO 30 PERCENT. PRECLUDING A RED FLAG WARNING AT
THIS TIME IS A COMBINATION OF THE COOL TEMPERATURES...THE RECENT
SOAKING RAIN ON THURSDAY RESULTING IN WETTER FUELS...AND GREEN
UP THAT REALLY TOOK OFF THIS WEEK.
HEADING INTO EARLY NEXT WEEK...FOCUS REMAINS ON TUESDAY AS
SOUTHEAST MINNESOTA AND NORTHEAST IOWA BECOME POSITIONED IN A VERY
WARM ENVIRONMENT. TEMPERATURES LOOK TO CLIMB INTO THE MID TO UPPER
80S...AND PERHAPS COULD EVEN CLIMB INTO THE LOW 90S. DEWPOINT
FORECASTS ARE A LITTLE DIFFICULT AT THIS TIME WITH MOST MODELS
APPEARING TO OVERDO THEM...BUT RELATIVE HUMIDITIES SHOULD DROP AT
LEAST TO 35 TO 40 PERCENT. IT IS POSSIBLE THESE COULD END UP LOWER
AS CERTAINTY ON DEWPOINTS INCREASES. WINDS LOOK MARGINAL RIGHT
NOW FOR RED FLAG CONDITIONS. NEEDLESS TO SAY...SOMETHING TO KEEP
AN EYE ON OVER THE NEXT FEW DAYS.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...FREEZE WATCH FROM LATE SUNDAY NIGHT THROUGH MONDAY MORNING FOR
WIZ017-029-034-042>044.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION...DAS
FIRE WEATHER...AJ
AREA FORECAST DISCUSSION
NWS TAUNTON MA
422 PM EDT SAT MAY 11 2013
.SYNOPSIS...
SHOWERS AND OCCASIONAL THUNDERSTORMS CONTINUE THIS EVENING AND
OVERNIGHT AS A COLD FRONT SLOWLY CROSSES THE REGION. THE FRONT
WILL THEN STALL SUNDAY BEFORE MOVING TO THE EAST SUNDAY NIGHT.
COOLER AND DRIER WEATHER WILL FOLLOW FOR EARLY NEXT WEEK. EXPECT A
RETURN TO A MORE UNSETTLED PATTERN FOR THE LATTER PART OF NEXT
WEEK AS A FRONT STALLS OVER OR JUST SOUTH OF THE AREA.
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
* SOME THUNDER THIS EVENING AND OVERNIGHT.
* PRIMARY THREATS...GUSTY WINDS AND OCCASIONAL URBAN/POOR DRAINAGE
FLOODING
INITIAL CONVECTIVE BAND CONTINUES TO WEAKEN ALONG THE S COASTAL
WATERS AND WILL CLIP SE MA AND SRN RI THROUGH THE EARLY EVENING.
MOST OF THE THUNDER ASSOCIATED WITH THIS BAND SHOULD REMAIN WELL S
OF LAND PRIMARILY DUE TO MOSTLY CLEAR SKIES WHICH HAVE STAYED
FURTHER S ALL DAY. CONDITIONS ARE GENERALLY MORE STABLE TO THE N.
HOWEVER...WILL NEED TO CONTINUE TO MONITOR DEVELOPING CONVECTION
MORE CLOSELY ASSOCIATED WITH A COLD FRONTAL BOUNDARY CURRENTLY
LOCATED THROUGH CENTRAL NY AND INTO PA. COMBINATION OF SLIGHTLY
HIGHER DWPTS AND SOME CLEARING OF THE MID AND HIGH LVL CLOUDS HAS
ALLOWED CONVECTION TO FIRE AND BECOME A BIT MORE ORGANIZED IN SRN
NY AND NJ. WILL NEED TO MONITOR THIS AS THE FRONT MAKES ITS E
PROGRESSION. MESOSCALE MODELS CONTINUE TO INDICATE SOME
DESTABILIZATION OVER SRN NEW ENGLAND...BUT NOT NEARLY AS MUCH AS
WHERE CLEARING HAS OCCURRED. THEREFORE...WILL HAVE TO WATCH THE
CLEARING THROUGH THE EVENING WHILE THE SUN IS STILL UP. SB CAPE
VALUES HAVE SHOT UP TO ABOUT 1000 J/KG IN THE AREAS WHERE CLEARING
HAS OCCURRED. SHEAR STILL DECENT...WITH 30-40 KT 0-6KM OUT OF THE
W...HOWEVER IT WOULD NEED THE BETTER DESTABILIZATION FOR ANY
STORMS TO BECOME ORGANIZED.
OVERNIGHT HOWEVER...THE TREND WILL BE TOWARD SOME UPPER LVL
INSTABILITY AS NOSE OF 40 KT LLJ MOVES OVER ESPECIALLY S AND SE
AREAS. STILL NOTING 1.0+ INCH PWAT AIRMASS AND DECENT THETA-E
RIDGING TO WORK WITH PARTICULARLY RI AND E MASS AFTER THE BAND OF
INTERIOR CONVECTION WEAKENS WITH TIME OVER THE AREA.
THEREFORE...THE TRANSITION...AND PRIMARY THREAT WILL BE TOWARD THE
POTENTIAL FOR ISOLATED HEAVY DOWNPOURS WITH A FOCUS ON THE E AS
THE FRONT BEGINS TO CROSS THE AREA AND STALL. THUNDER STILL NOT
OUR OF THE QUESTION...BUT ITS LIKELY TO BE MORE ISOLATED IN NATURE
THAN THIS AFTERNOON AND EARLY EVENING. TYPICAL POOR DRAINAGE
FLOODING IS POSSIBLE IN SOME SPOTS...PARTICULARLY WITH ANY
CONVECTIVE ELEMENTS THAT FORM THIS EVENING OR OVERNIGHT. HRRR POPS
HAVE BEEN QUITE GOOD TODAY...SO ADJUSTED THE EVENING AND OVERNIGHT
POPS TOWARD ITS SOLUTION.
&&
.SHORT TERM /6 AM SUNDAY MORNING THROUGH SUNDAY NIGHT/...
SUNDAY...
SFC COLD FRONT PROGGED TO STALL IN ERN MA DURING THE EARLY MORNING
HOURS UNTIL SECONDARY KICKER WAVE ROTATES W TO E AROUND THE CUTOFF
LOW PRES IN QUEBEC. AT THE SAME TIME...MODELS CONTINUE TO INDICATE
A SECONDARY SURGE OF HIGHER THETA-E ARE AND A SECONDARY LLJ TO
MOVE UP AND E OF THE THIS FRONT DURING THE MORNING HOURS. GIVEN
THIS...EVEN AS BULK OF PRECIP SLOWLY SHIFTS OFFSHORE OF ERN MA AND
THE CAPE/ISLANDS...MAY SEE ANOTHER HEAVIER BAND OF PRECIPITATION
FORM DURING THE DAYLIGHT HOURS AND CROSS FROM S TO N PARTICULARLY
OVER E AND SE PORTIONS OF THE FORECAST AREA. ALSO...WITH SOME
BREAKS POSSIBLE...AND THE CONVERGENCE PROVIDED BY THE FRONT...MAY
SEE -SHRA AND EVEN AN ISOLATED RUMBLE OF THUNDER AS FAR WEST AS A
IJD-ORH-MHT LINE. HOWEVER...WITH THE COMBINATION OF THIS KICKER
WAVE ALLOWING THE FRONT TO PROGRESS...AND A DRIER MORE STABLE
AIRMASS FILTERING IN BEHIND THE FRONT...NOT EXPECTING RAINFALL TO
BE AS WIDESPREAD OR AS POTENTIALLY HEAVY EVERYWHERE AS IT WAS ON
SATURDAY. MOST LOCATIONS W OF THE LINE ABOVE REMAIN DRY AND
PROGRESSIVELY GIVE WAY TO SUNNY SKIES. THIS TOO WILL BE THE TREND
FOR THE EAST BY LATE AFTERNOON AND EVENING MODELS INDICATE. WILL
NEED TO WATCH SE MASS...CAPE/ISLANDS ESPECIALLY FOR ANY HEAVY
RAINFALL. MAY NEED TO MONITOR THE CAPE/ISLANDS FOR A SECONDARY
DENSE FOG THREAT SHOULD THE PRECIP MOVE A LITTLE BIT FURTHER
OFFSHORE...BUT WITH RAIN MIXING IN THE BL...IT APPEARS TO BE A
SLIGHTLY LOWER THREAT THAN PREVIOUS NIGHTS.
SUN NIGHT...
CLEARING TREND EXPECTED DURING THE OVERNIGHT HOURS. HOWEVER...SFC
PRES GRADIENT IS EXPECTED TO REMAIN AT LEAST SOMEWHAT TIGHT...SO
NOT EXPECTING FULL DECOUPLING. EVEN STILL TEMPERATURES ARE
EXPECTED TO DIP TO NEAR FREEZING IN NW MA AND PORTIONS OF SW NH
WITH MID TO UPPER 30S TOWARD THE S AND E. WINDS AROUND 10 MPH
WOULD PRECLUDE FROST POTENTIAL...BUT THIS WILL NEED TO BE
MONITORED GIVEN NEWLY ACTIVATED GROWING SEASON IN SOME SPOTS AND
TEMPERATURES DIPPING CLOSE TO THE FREEZING MARK.
&&
.LONG TERM /MONDAY THROUGH SATURDAY/...
HIGHLIGHTS...
* COOL AND DRY MONDAY AND TUESDAY
* UNSETTLED WEATHER THE LATTER HALF OF THE WEEK
THERE IS REASONABLY GOOD AGREEMENT ON THE LARGE SCALE PATTERN BY
THE MEDIUM RANGE MODELS THROUGH THE COMING WEEK. RELATIVELY HIGH
AMPLITUDE TROF BRINGS UNSEASONABLY CHILLY AIR MASS TO THE REGION
MON THRU TUE NIGHT. RIDGE ACROSS THE S CENTRAL US BUILDS EAST ON
WED BUT STRONG TROF ACROSS CANADA SHOULD KEEP RELATIVELY FAST WEST
TO EAST FLOW ACROSS SOUTHERN NEW ENGLAND WITH A HIGH LIKELIHOOD OF
A FRONT STALLING OVER OR JUST SOUTH OF THE FORECAST AREA. BY THE
WEEKEND...LOOKS LIKE A DRY NW FLOW BECOMES ESTABLISHED OVER THE
AREA WITH DRY AND PROBABLY SEASONABLE TEMPERATURES.
MON THRU TUE NIGHT...SHOULD BE DRY AND COOL WITH -1 TO -3C 850MB
TEMP AIR. THE AVERAGE START OF THE GROWING SEASON EXPANDED INTO A
LARGE PART...BUT NOT ALL...OF INTERIOR SOUTHERN NEW ENGLAND ON MAY
10. THERE MAY BE A NEED FOR FROST ADVISORIES OR FREEZE WARNINGS
FOR A PORTION OF THE AREA MON NIGHT UNDER CLEAR SKIES AND PROBABLY
DECOUPLING WINDS OVER THE INTERIOR TO ASSIST WITH RADIATIONAL
COOLING...ALBEIT FOR A RELATIVELY SHORT NIGHT AT THIS TIME OF
YEAR.
WED INTO WED NIGHT...SPELL A CHANGE IN THE WEATHER PATTERN.
ALTHOUGH THERE ARE SOME TIMING DIFFERENCES...MEDIUM RANGE MODELS
SUGGEST WARM ADVECTION BECOMING ESTABLISHED ON WED...AND BY WED
EVENING THE WARM ADVECTION MAY TRIGGER ENOUGH OF AN INSTABILITY
BURST AS SEEN IN K INDEX PROJECTIONS FOR AT LEAST SCT SHOWERS AND
TSTMS.
THU THRU FRI...WILL PROBABLY BE UNSETTLED AS FRONTAL BOUNDARY
STALLS OVER OR A LITTLE SOUTH OF SOUTHERN NEW ENGLAND AND REGION
IS VULNERABLE SHORT WAVE ENERGY PASSING BETWEEN A SOUTHERN UPPER
RIDGE AND E CENTRAL CANADA TROF. IT IS TOO FAR OUT IN TIME TO HAVE
MUCH CONFIDENCE IN DETAILS BUT FOR NOW INDICATED CONSIDERABLE
CLOUDINESS AND CHANCE SHOWERS/TSTMS.
SAT...BOTH 12Z ECMWF AND GFS SUGGEST A DRIER NW FLOW BECOMING
ESTABLISHED ALTHOUGH CONFIDENCE THAT FAR OUT IS NOT TOO HIGH. BY
THE WEEKEND...DIFFERENCES IN THE SYNOPTIC FLOW BECOME MORE
APPARENT WITH THE ECMWF DEPICTING A STRONGER NORTHERN STREAM AND
THE GFS SHOWING A WEAKER NORTHERN STREAM.
&&
.AVIATION /20Z SATURDAY THROUGH THURSDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
OVERVIEW...LOW CONFIDENCE...PARTICULARLY ON TIMING OF ANY LOW
CIGS/VSBYS INTO SUN MORNING.
THROUGH MID MORNING SUN...
AS A SLOW MOVING COLD FRONT CROSSES THE AREA...EXPECTING A COMPLEX
MIX OF VFR/MVFR/IFR THIS AFTERNOON IN OCCASIONAL -SHRA AND LOW
CIGS. A THUNDERSTORM OR TWO CAN/T BE RULED OUT LATE THIS AFTERNOON
OR EVENING AS WELL. OTHERWISE...THE TREND WILL BE TOWARD ALL IFR
AS FOG AND LOW CIGS DEVELOP THIS EVENING AND LINGER MUCH OF THE
NIGHT. SHOWERS CONTINUE ACROSS THE REGION DURING THIS TIME AS
WELL. EXPECT IMPROVEMENT FROM W TO E DURING THE EARLY TO MID
MORNING HOURS...BUT WILL LIKELY SEE MOSTLY IFR IN THE EAST.
EARLY AFTERNOON SUN THROUGH SUN NIGHT...
IMPROVING CONDITIONS WITH LIKELY VFR EVERYWHERE BY AFTERNOON SUN.
THE VFR CONDITIONS CONTINUE INTO SUN NIGHT. WINDS MAY GUST TO 20
KT DURING THE DAY SUN OUT OF THE W.
KBOS TERMINAL...OVERALL LOW CONFIDENCE ON CIG FORECAST. WE HAVE
MAINLY VFR CIGS TODAY...LOWERING TO IFR TONIGHT. BUT LOWER CIGS
COULD DEVELOP EARLIER.
KBDL TERMINAL...MODERATE CONFIDENCE IN TAF.
OUTLOOK...MONDAY THROUGH THURSDAY...
HIGH CONFIDENCE OF VFR CONDITIONS MON THROUGH MUCH OF WED.
MODERATE CONFIDENCE OF DEVELOPING MVFR CONDITIONS IN SHOWERS AND
PATCHY FOG WED EVE AND OCCASIONAL MVFR CONDITIONS IN SCT
SHOWERS/TSTMS AND PATCHY FOG WED NIGHT THRU THU.
&&
.MARINE...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
FORECAST CONFIDENCE HIGH THROUGH SUNDAY NIGHT.
OVERNIGHT...WINDS OF 25-30 KT GRADUALLY SUBSIDE THIS
EVENING...EXCEPT FOR THE POTENTIAL FOR HIGHER GUSTS IN ANY
THUNDERSTORMS WHICH MAY CROSS THE WATERS /PARTICULARLY SRN
WATERS/ OVERNIGHT. HOWEVER...SEAS WITH BUILDING SWELL ARE LIKELY
TO STAY ELEVATED 5-7 FT OVER SRN WATERS AND E OUTER WATERS. SMALL
CRAFT ADVISORIES CONTINUE.
SUNDAY...
SMALL CRAFT ADVISORIES CONTINUE FOR SEAS ON THE OUTER WATERS SRN
WATERS IMMEDIATELY S OF RHODE ISLAND. HOWEVER...MAY SEE A SECOND
SURGE OF WIND GUSTS...PARTICULARLY NEAR SHORE...TO 25 KT. SO MAY
NEED TO RE-ISSUE SMALL CRAFT ADVISORY FOR THE DAYLIGHT HOURS ON
SOME NEAR SHORE ZONES.
SUN NIGHT...
ASIDE FROM CONTINUING SWELL ON OUTER WATERS /WHERE SCA CONTINUES/
SEAS AND WINDS SUBSIDE.
OUTLOOK...MONDAY THROUGH THURSDAY...
ENOUGH NW TO N GRADIENT MAY RESULT IN SCA GUSTS OVER THE COASTAL
WATERS MON INTO MON EVE. LIGHT WINDS AND SUBSIDING SEAS EXPECTED
TUE. ALTHOUGH WINDS WILL BE INCREASING ALOFT...SURFACE WINDS ARE
PRESENTLY EXPECTED TO REMAIN LIGHT WED INTO THU...EXCEPT IN
VICINITY OF ANY ISOLD TSTMS WED NIGHT AND THU.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...NONE.
NH...NONE.
RI...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR
ANZ230>234-236-251.
SMALL CRAFT ADVISORY UNTIL 8 PM EDT SUNDAY FOR ANZ235-237-250.
SMALL CRAFT ADVISORY UNTIL 8 AM EDT MONDAY FOR ANZ254>256.
&&
$$
SYNOPSIS...DOODY/THOMPSON
NEAR TERM...DOODY
SHORT TERM...DOODY
LONG TERM...THOMPSON
AVIATION...DOODY/THOMPSON
MARINE...DOODY/THOMPSON
AREA FORECAST DISCUSSION
NWS TAUNTON MA
401 PM EDT SAT MAY 11 2013
.SYNOPSIS...
SHOWERS AND OCCASIONAL THUNDERSTORMS CONTINUE THIS EVENING AND
OVERNIGHT AS A COLD FRONT SLOWLY CROSSES THE REGION. THE FRONT
WILL THEN STALL SUNDAY BEFORE MOVING TO THE EAST SUNDAY NIGHT.
COOLER AND DRIER WEATHER WILL FOLLOW FOR EARLY NEXT WEEK. EXPECT A
RETURN TO A MORE UNSETTLED PATTERN FOR THE LATTER PART OF NEXT
WEEK.
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
* SOME THUNDER THIS EVENING AND OVERNIGHT.
* PRIMARY THREATS...GUSTY WINDS AND OCCASIONAL URBAN/POOR DRAINAGE
FLOODING
INITIAL CONVECTIVE BAND CONTINUES TO WEAKEN ALONG THE S COASTAL
WATERS AND WILL CLIP SE MA AND SRN RI THROUGH THE EARLY EVENING.
MOST OF THE THUNDER ASSOCIATED WITH THIS BAND SHOULD REMAIN WELL S
OF LAND PRIMARILY DUE TO MOSTLY CLEAR SKIES WHICH HAVE STAYED
FURTHER S ALL DAY. CONDITIONS ARE GENERALLY MORE STABLE TO THE N.
HOWEVER...WILL NEED TO CONTINUE TO MONITOR DEVELOPING CONVECTION
MORE CLOSELY ASSOCIATED WITH A COLD FRONTAL BOUNDARY CURRENTLY
LOCATED THROUGH CENTRAL NY AND INTO PA. COMBINATION OF SLIGHTLY
HIGHER DWPTS AND SOME CLEARING OF THE MID AND HIGH LVL CLOUDS HAS
ALLOWED CONVECTION TO FIRE AND BECOME A BIT MORE ORGANIZED IN SRN
NY AND NJ. WILL NEED TO MONITOR THIS AS THE FRONT MAKES ITS E
PROGRESSION. MESOSCALE MODELS CONTINUE TO INDICATE SOME
DESTABILIZATION OVER SRN NEW ENGLAND...BUT NOT NEARLY AS MUCH AS
WHERE CLEARING HAS OCCURRED. THEREFORE...WILL HAVE TO WATCH THE
CLEARING THROUGH THE EVENING WHILE THE SUN IS STILL UP. SB CAPE
VALUES HAVE SHOT UP TO ABOUT 1000 J/KG IN THE AREAS WHERE CLEARING
HAS OCCURRED. SHEAR STILL DECENT...WITH 30-40 KT 0-6KM OUT OF THE
W...HOWEVER IT WOULD NEED THE BETTER DESTABILIZATION FOR ANY
STORMS TO BECOME ORGANIZED.
OVERNIGHT HOWEVER...THE TREND WILL BE TOWARD SOME UPPER LVL
INSTABILITY AS NOSE OF 40 KT LLJ MOVES OVER ESPECIALLY S AND SE
AREAS. STILL NOTING 1.0+ INCH PWAT AIRMASS AND DECENT THETA-E
RIDGING TO WORK WITH PARTICULARLY RI AND E MASS AFTER THE BAND OF
INTERIOR CONVECTION WEAKENS WITH TIME OVER THE AREA.
THEREFORE...THE TRANSITION...AND PRIMARY THREAT WILL BE TOWARD THE
POTENTIAL FOR ISOLATED HEAVY DOWNPOURS WITH A FOCUS ON THE E AS
THE FRONT BEGINS TO CROSS THE AREA AND STALL. THUNDER STILL NOT
OUR OF THE QUESTION...BUT ITS LIKELY TO BE MORE ISOLATED IN NATURE
THAN THIS AFTERNOON AND EARLY EVENING. TYPICAL POOR DRAINAGE
FLOODING IS POSSIBLE IN SOME SPOTS...PARTICULARLY WITH ANY
CONVECTIVE ELEMENTS THAT FORM THIS EVENING OR OVERNIGHT. HRRR POPS
HAVE BEEN QUITE GOOD TODAY...SO ADJUSTED THE EVENING AND OVERNIGHT
POPS TOWARD ITS SOLUTION.
&&
.SHORT TERM /6 AM SUNDAY MORNING THROUGH SUNDAY NIGHT/...
SUNDAY...
SFC COLD FRONT PROGGED TO STALL IN ERN MA DURING THE EARLY MORNING
HOURS UNTIL SECONDARY KICKER WAVE ROTATES W TO E AROUND THE CUTOFF
LOW PRES IN QUEBEC. AT THE SAME TIME...MODELS CONTINUE TO INDICATE
A SECONDARY SURGE OF HIGHER THETA-E ARE AND A SECONDARY LLJ TO
MOVE UP AND E OF THE THIS FRONT DURING THE MORNING HOURS. GIVEN
THIS...EVEN AS BULK OF PRECIP SLOWLY SHIFTS OFFSHORE OF ERN MA AND
THE CAPE/ISLANDS...MAY SEE ANOTHER HEAVIER BAND OF PRECIPITATION
FORM DURING THE DAYLIGHT HOURS AND CROSS FROM S TO N PARTICULARLY
OVER E AND SE PORTIONS OF THE FORECAST AREA. ALSO...WITH SOME
BREAKS POSSIBLE...AND THE CONVERGENCE PROVIDED BY THE FRONT...MAY
SEE -SHRA AND EVEN AN ISOLATED RUMBLE OF THUNDER AS FAR WEST AS A
IJD-ORH-MHT LINE. HOWEVER...WITH THE COMBINATION OF THIS KICKER
WAVE ALLOWING THE FRONT TO PROGRESS...AND A DRIER MORE STABLE
AIRMASS FILTERING IN BEHIND THE FRONT...NOT EXPECTING RAINFALL TO
BE AS WIDESPREAD OR AS POTENTIALLY HEAVY EVERYWHERE AS IT WAS ON
SATURDAY. MOST LOCATIONS W OF THE LINE ABOVE REMAIN DRY AND
PROGRESSIVELY GIVE WAY TO SUNNY SKIES. THIS TOO WILL BE THE TREND
FOR THE EAST BY LATE AFTERNOON AND EVENING MODELS INDICATE. WILL
NEED TO WATCH SE MASS...CAPE/ISLANDS ESPECIALLY FOR ANY HEAVY
RAINFALL. MAY NEED TO MONITOR THE CAPE/ISLANDS FOR A SECONDARY
DENSE FOG THREAT SHOULD THE PRECIP MOVE A LITTLE BIT FURTHER
OFFSHORE...BUT WITH RAIN MIXING IN THE BL...IT APPEARS TO BE A
SLIGHTLY LOWER THREAT THAN PREVIOUS NIGHTS.
SUN NIGHT...
CLEARING TREND EXPECTED DURING THE OVERNIGHT HOURS. HOWEVER...SFC
PRES GRADIENT IS EXPECTED TO REMAIN AT LEAST SOMEWHAT TIGHT...SO
NOT EXPECTING FULL DECOUPLING. EVEN STILL TEMPERATURES ARE
EXPECTED TO DIP TO NEAR FREEZING IN NW MA AND PORTIONS OF SW NH
WITH MID TO UPPER 30S TOWARD THE S AND E. WINDS AROUND 10 MPH
WOULD PRECLUDE FROST POTENTIAL...BUT THIS WILL NEED TO BE
MONITORED GIVEN NEWLY ACTIVATED GROWING SEASON IN SOME SPOTS AND
TEMPERATURES DIPPING CLOSE TO THE FREEZING MARK.
&&
.LONG TERM /MONDAY THROUGH SATURDAY/...
HIGHLIGHTS...
* COOLER AND DRIER WEATHER MONDAY AND TUESDAY
* MORE UNSETTLED WEATHER RETURNS MIDDLE OF NEXT WEEK
THE MODELS EXHIBIT GOOD AGREEMENT ON SYNOPTIC SCALE FEATURES
THROUGHOUT MUCH OF THE FORECAST PERIOD. HIGH PRESSURE BUILDS INTO
SOUTHERN NEW ENGLAND MONDAY AND TUESDAY AS LOW PRESSURE MOVES UP
THE COAST...PASSING EAST OF SOUTHERN NEW ENGLAND TUESDAY. SHOWERS
ARE POSSIBLE WEDNESDAY AHEAD OF A COLD FRONT THAT WILL MOVE
THROUGH THE AREA THURSDAY. THERE ARE SOME DIFFERENCES BETWEEN THE
GFS AND ECMWF TOWARDS THE END OF NEXT WEEK. THE EURO IS SLOWER
MOVING AN EAST COAST RIDGE OUT TO SEA WHILE THE GFS MOVES IT OUT
FAIRLY QUICKLY ALLOWING ANOTHER LOW PRESSURE SYSTEM TO AFFECT THE
AREA FRIDAY. GENERALLY WENT WITH A BLEND OF GUIDANCE FOR THE
FORECAST.
SUNDAY NIGHT THROUGH WEDNESDAY...HIGH PRESSURE STARTS TO BUILD
INTO THE EAST MONDAY AND TUESDAY AS LOW PRESSURE MOVES UP THE
COAST WELL EAST OF THE AREA INTO THE MARITIMES. THE HIGH PRESSURE
WILL MOVE OFFSHORE WEDNESDAY. MUCH OF THIS PERIOD IS EXPECTED TO
BE DRY... THOUGH A COLD CORE ALOFT WILL STEEPEN LAPSE RATES ENOUGH
THAT TOGETHER WITH DAYTIME HEATING COULD PRODUCE SOME DIURNAL
SHOWERS. BELOW AVERAGE TEMPERATURES ARE EXPECTED WITH MOSTLY SUNNY
SKIES. THE BIG IMPACT HERE WILL BE OVERNIGHT...WITH TEMPERATURES
EXPECTED TO DROP INTO THE 30S. WILL KEEP THE FROST WORDING IN THE
WEATHER GRIDS. MONDAY NIGHT LOOKS TO BE THE CHILLIEST NIGHT WITH
TEMPERATURES POSSIBLY DOWN TO FREEZING ACROSS PORTIONS OF THE
NORTHWESTERN ZONES.
THURSDAY AND FRIDAY...PLENTY OF UNCERTAINTY HERE WITH DIFFERENT
SYNOPTIC PATTERNS IN THE MODELS. THE ECMWF KEEPS THE UPPER LEVEL
RIDGE OVER THE EAST COAST A BIT LONGER THAN THE GFS. REGARDLESS...
THIS PERIOD LOOKS TO BE A BIT MORE UNSETTLED THAN EARLIER IN THE
WEEK. IT DOES LOOK AS THOUGH TEMPERATURES WILL RETURN TO NORMAL
OR POSSIBLY ABOVE NORMAL LEVELS THROUGH THE END OF THE WEEK.
&&
.AVIATION /19Z SATURDAY THROUGH THURSDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
OVERVIEW...LOW CONFIDENCE...PARTICULARLY ON TIMING OF ANY LOW
CIGS/VSBYS INTO SUN MORNING.
THROUGH MID MORNING SUN...
AS A SLOW MOVING COLD FRONT CROSSES THE AREA...EXPECTING A COMPLEX
MIX OF VFR/MVFR/IFR THIS AFTERNOON IN OCCASIONAL -SHRA AND LOW
CIGS. A THUNDERSTORM OR TWO CAN/T BE RULED OUT LATE THIS AFTERNOON
OR EVENING AS WELL. OTHERWISE...THE TREND WILL BE TOWARD ALL IFR
AS FOG AND LOW CIGS DEVELOP THIS EVENING AND LINGER MUCH OF THE
NIGHT. SHOWERS CONTINUE ACROSS THE REGION DURING THIS TIME AS
WELL. EXPECT IMPROVEMENT FROM W TO E DURING THE EARLY TO MID
MORNING HOURS...BUT WILL LIKELY SEE MOSTLY IFR IN THE EAST.
EARLY AFTERNOON SUN THROUGH SUN NIGHT...
IMPROVING CONDITIONS WITH LIKELY VFR EVERYWHERE BY AFTERNOON SUN.
THE VFR CONDITIONS CONTINUE INTO SUN NIGHT. WINDS MAY GUST TO 20
KT DURING THE DAY SUN OUT OF THE W.
KBOS TERMINAL...OVERALL LOW CONFIDENCE ON CIG FORECAST. WE HAVE
MAINLY VFR CIGS TODAY...LOWERING TO IFR TONIGHT. BUT LOWER CIGS
COULD DEVELOP EARLIER.
KBDL TERMINAL...MODERATE CONFIDENCE IN TAF.
OUTLOOK...SUNDAY NIGHT THROUGH WEDNESDAY...
SUNDAY NIGHT THROUGH WEDNESDAY...MODERATE CONFIDENCE. MAINLY VFR.
COULD SEE MVFR/IFR CONDITIONS IN DIURNAL SHOWERS EACH DAY.
&&
.MARINE...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
FORECAST CONFIDENCE HIGH THROUGH SUNDAY NIGHT.
OVERNIGHT...WINDS OF 25-30 KT GRADUALLY SUBSIDE THIS
EVENING...EXCEPT FOR THE POTENTIAL FOR HIGHER GUSTS IN ANY
THUNDERSTORMS WHICH MAY CROSS THE WATERS /PARTICULARLY SRN
WATERS/ OVERNIGHT. HOWEVER...SEAS WITH BUILDING SWELL ARE LIKELY
TO STAY ELEVATED 5-7 FT OVER SRN WATERS AND E OUTER WATERS. SMALL
CRAFT ADVISORIES CONTINUE.
SUNDAY...
SMALL CRAFT ADVISORIES CONTINUE FOR SEAS ON THE OUTER WATERS SRN
WATERS IMMEDIATELY S OF RHODE ISLAND. HOWEVER...MAY SEE A SECOND
SURGE OF WIND GUSTS...PARTICULARLY NEAR SHORE...TO 25 KT. SO MAY
NEED TO RE-ISSUE SMALL CRAFT ADVISORY FOR THE DAYLIGHT HOURS ON
SOME NEAR SHORE ZONES.
SUN NIGHT...
ASIDE FROM CONTINUING SWELL ON OUTER WATERS /WHERE SCA CONTINUES/
SEAS AND WINDS SUBSIDE.
OUTLOOK...SUNDAY NIGHT THROUGH WEDNESDAY...
EXPECT SEAS OF 5 TO 7 FEET ON THE OUTER WATERS SUNDAY NIGHT. SEAS
WILL DIMINISH MONDAY THROUGH WEDNESDAY AS HIGH PRESSURE BUILDS
OVER THE WATERS. SCA SEAS WILL CONTINUE ON THE OUTER WATERS
THROUGH MONDAY AFTERNOON. WESTERLY WINDS WILL FLIRT WITH SCA
CRITERIA SUNDAY NIGHT.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...NONE.
NH...NONE.
RI...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR
ANZ230>234-236-251.
SMALL CRAFT ADVISORY UNTIL 8 PM EDT SUNDAY FOR ANZ235-237-250.
SMALL CRAFT ADVISORY UNTIL 8 AM EDT MONDAY FOR ANZ254>256.
&&
$$
SYNOPSIS...DOODY/THOMPSON
NEAR TERM...DOODY
SHORT TERM...DOODY
LONG TERM...THOMPSON
AVIATION...DOODY/THOMPSON
MARINE...DOODY/THOMPSON
AREA FORECAST DISCUSSION...CORRECTED
NWS MIAMI FL
210 PM EDT SAT MAY 11 2013
...CORRECTED LONG RANGE TIME FRAME...
.SHORT TERM (TONIGHT THROUGH MONDAY NIGHT)...
SOUTH FLORIDA IS CURRENTLY UNDER NEAR ZONAL FLOW WITH A MID LEVEL
RIDGE TO THE EAST AND A LARGE CUT-OFF LOW OVER NORTHERN MEXICO. A
FAST MOVING WAVE IS EMBEDDED IN THE ZONAL FLOW PATTERN CURRENTLY
MOVING INTO THE FLORIDA PANHANDLE WITH A LARGE CLUSTER OF CONVECTION
ASSOCIATED WITH IT. THE PROXIMITY OF THIS WAVE ALONG WITH PLENTY OF
SUNSHINE EARLY TODAY AND INSTABILITY WILL CAUSE ANOTHER ROUND OF
LATE AFTERNOON AND EARLY EVENING THUNDERSTORMS DEVELOPING OVER THE
INTERIOR AND THEN WILL DRIFT BACK TOWARDS THE EAST COAST. AT THE
SURFACE, A RIDGE IS LOCATED ACROSS SOUTH FLORIDA PRODUCING A LOW
LEVEL SOUTHERLY FLOW WHICH WILL TEND TO KEEP THE INITIATION OF
CONVECTION WELL INLAND FROM THE COASTS OF MIAMI-DADE AND COLLIER
COUNTIES.
LOOKING UPSTREAM, A MAJOR MID LEVEL TROUGH WILL DEEPEN ACROSS
EASTERN NORTH AMERICA THROUGH MONDAY WITH ITS ASSOCIATED WEAKENING
COLD FRONT MOVING INTO NORTH FLORIDA ON SUNDAY AND INTO SOUTH
FLORIDA BY LATE MONDAY. THIS WILL PROVIDE A CONTINUED THREAT FOR
MAINLY AFTERNOON AND EVENING CONVECTION FAVORING THE INTERIOR AND
EAST COAST. FORECAST SOUNDINGS SHOW SLOW STORM MOTION AGAIN ON
SUNDAY BUT A STRONGER WESTERLY STEERING FLOW ON MONDAY AS THE TROUGH
DEEPENS FURTHER. THE PWAT IS ALSO FORECAST TO REMAIN IN THE RANGE OF
1.5-1.7 INCHES WHICH IS ABOVE THE AVERAGE FOR MID MAY. IN ADDITION,
500 MB TEMPERATURES ARE FORECAST TO HOVER AROUND -10 TO -11 CELSIUS
THROUGH MONDAY AND THIS IS ONE TO TWO DEGREES BELOW THE AVERAGE SO
ALSO ADDING FUEL TO THE MIX. THE COLD FRONT WILL PUSH OFF THE
SOUTHEAST COAST MONDAY EVENING AND BRING A REFRESHING FEELING TO
THE AIR WITH TEMPERATURES FALLING TO ABOUT 8-10 DEGREES BELOW
NORMAL MONDAY NIGHT.
.LONG TERM (TUESDAY THROUGH SATURDAY)... THE TROUGH WILL BEGIN TO
SHIFT EAST ON TUESDAY WITH A RIDGE BUILDING ACROSS THE GULF OF
MEXICO WHICH WILL FILTER A MUCH DRIER AIR MASS INTO SOUTH FLORIDA
CONTINUING THROUGH MUCH OF THE WEEK. THERE IS HOWEVER ONE
DISCREPANCY IN THE LONG RANGE MODELS BY THE END OF THE FORECAST.
BOTH THE ECMWF AND GFS SHOW THE CUT-OFF LOW CURRENTLY OVER
NORTHERN MEXICO TO BEGIN LIFTING EASTWARD BY THE MIDDLE OF THE
WEEK. HOWEVER, THE 00Z RUN OF THE ECMWF SHOWS THIS LOW SHIFTING
NEARLY DUE EAST AND ACROSS NORTH FLORIDA BY FRIDAY AND SATURDAY
WHICH WOULD TEND TO DESTABILIZE SOUTH FLORIDA ONCE AGAIN WHILE THE
LAST FEW RUNS OF THE GFS HAVE SHOWN THE LOW LIFTING MORE TO THE
NORTHEAST WELL NORTH OF THE PENINSULA. THE 12Z RUN HAS SHIFTED A
TAD FARTHER TO THE SOUTH BUT WILL WAIT FOR MORE CONSISTENT RUNS
BEFORE ADJUSTING THE FORECAST KEEPING IT DRY FOR NOW INTO NEXT
WEEKEND.
&&
.AVIATION...
SHRAS/TSRAS ALREADY BEGINNING TO DEVELOP ACROSS INTERIOR SECTIONS OF
PALM BEACH...BROWARD...AND MIAMI-DADE COUNTIES EARLY THIS AFTERNOON.
THIS ACTIVITY WILL CONTINUE THROUGH THE LATE AFTERNOON AND EARLY
EVENING HOURS MUCH LIKE YESTERDAY. LATEST HRRR DEPICTS FURTHER
ACTIVITY DEVELOPING ACROSS THE INTERIOR OVER THE NEXT FEW HOURS AND
PUSHING EAST AS A RESULT OF THE GULF BREEZE THAT IS ALREADY WELL
ESTABLISHED. PLACED VCTS AT ALL EAST COAST TERMINAL SITES EXCEPT FOR
KTMB THROUGH THE EARLY EVENING HOURS. ACTIVITY SHOULD QUICKLY
DIMINISH WITH LOSS OF HEATING. FLOW SHOULD THEN GENERALLY BE
SOUTHERLY AND LIGHT OVERNIGHT.
&&
.MARINE...
TRANQUIL WIND AND SEAS WILL CONTINUE THROUGH THE WEEKEND OUTSIDE
OF ISOLATED STRONG CONVECTION. A COLD FRONT WILL MOVE ACROSS THE
SOUTH FLORIDA WATERS LATE MONDAY WITH STRONG HIGH PRESSURE
BUILDING BEHIND THE FRONT WITH INCREASING WIND AND SEAS MONDAY
NIGHT INTO MID WEEK.
&&
.FIRE WEATHER...
NO PROBLEMS OR CONCERNS WITH AMPLE TROPICAL MOISTURE THROUGH MONDAY.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 74 86 73 85 / 30 50 30 30
FORT LAUDERDALE 77 86 74 85 / 30 50 20 50
MIAMI 76 87 75 87 / 30 40 20 50
NAPLES 73 87 73 85 / 20 20 20 20
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
DISCUSSION/MARINE/FIRE...30/KOB
AVIATION/RADAR...10/CD
AREA FORECAST DISCUSSION
NWS MIAMI FL
207 PM EDT SAT MAY 11 2013
.SHORT TERM (TONIGHT THROUGH MONDAY NIGHT)...
SOUTH FLORIDA IS CURRENTLY UNDER NEAR ZONAL FLOW WITH A MID LEVEL
RIDGE TO THE EAST AND A LARGE CUT-OFF LOW OVER NORTHERN MEXICO. A
FAST MOVING WAVE IS EMBEDDED IN THE ZONAL FLOW PATTERN CURRENTLY
MOVING INTO THE FLORIDA PANHANDLE WITH A LARGE CLUSTER OF CONVECTION
ASSOCIATED WITH IT. THE PROXIMITY OF THIS WAVE ALONG WITH PLENTY OF
SUNSHINE EARLY TODAY AND INSTABILITY WILL CAUSE ANOTHER ROUND OF
LATE AFTERNOON AND EARLY EVENING THUNDERSTORMS DEVELOPING OVER THE
INTERIOR AND THEN WILL DRIFT BACK TOWARDS THE EAST COAST. AT THE
SURFACE, A RIDGE IS LOCATED ACROSS SOUTH FLORIDA PRODUCING A LOW
LEVEL SOUTHERLY FLOW WHICH WILL TEND TO KEEP THE INITIATION OF
CONVECTION WELL INLAND FROM THE COASTS OF MIAMI-DADE AND COLLIER
COUNTIES.
LOOKING UPSTREAM, A MAJOR MID LEVEL TROUGH WILL DEEPEN ACROSS
EASTERN NORTH AMERICA THROUGH MONDAY WITH ITS ASSOCIATED WEAKENING
COLD FRONT MOVING INTO NORTH FLORIDA ON SUNDAY AND INTO SOUTH
FLORIDA BY LATE MONDAY. THIS WILL PROVIDE A CONTINUED THREAT FOR
MAINLY AFTERNOON AND EVENING CONVECTION FAVORING THE INTERIOR AND
EAST COAST. FORECAST SOUNDINGS SHOW SLOW STORM MOTION AGAIN ON
SUNDAY BUT A STRONGER WESTERLY STEERING FLOW ON MONDAY AS THE TROUGH
DEEPENS FURTHER. THE PWAT IS ALSO FORECAST TO REMAIN IN THE RANGE OF
1.5-1.7 INCHES WHICH IS ABOVE THE AVERAGE FOR MID MAY. IN ADDITION,
500 MB TEMPERATURES ARE FORECAST TO HOVER AROUND -10 TO -11 CELSIUS
THROUGH MONDAY AND THIS IS ONE TO TWO DEGREES BELOW THE AVERAGE SO
ALSO ADDING FUEL TO THE MIX. THE COLD FRONT WILL PUSH OFF THE
SOUTHEAST COAST MONDAY EVENING AND BRING A REFRESHING FEELING TO
THE AIR WITH TEMPERATURES FALLING TO ABOUT 8-10 DEGREES BELOW
NORMAL MONDAY NIGHT.
.LONG TERM (TUESDAY THROUGH SUNDAY)...
THE TROUGH WILL BEGIN TO SHIFT EAST ON TUESDAY WITH A RIDGE BUILDING
ACROSS THE GULF OF MEXICO WHICH WILL FILTER A MUCH DRIER AIR MASS
INTO SOUTH FLORIDA CONTINUING THROUGH MUCH OF THE WEEK. THERE IS
HOWEVER ONE DISCREPANCY IN THE LONG RANGE MODELS BY THE END OF THE
FORECAST. BOTH THE ECMWF AND GFS SHOW THE CUT-OFF LOW CURRENTLY
OVER NORTHERN MEXICO TO BEGIN LIFTING EASTWARD BY THE MIDDLE OF
THE WEEK. HOWEVER, THE 00Z RUN OF THE ECMWF SHOWS THIS LOW
SHIFTING NEARLY DUE EAST AND ACROSS NORTH FLORIDA BY FRIDAY AND
SATURDAY WHICH WOULD TEND TO DESTABILIZE SOUTH FLORIDA ONCE AGAIN
WHILE THE LAST FEW RUNS OF THE GFS HAVE SHOWN THE LOW LIFTING MORE
TO THE NORTHEAST WELL NORTH OF THE PENINSULA. THE 12Z RUN HAS
SHIFTED A TAD FARTHER TO THE SOUTH BUT WILL WAIT FOR MORE
CONSISTENT RUNS BEFORE ADJUSTING THE FORECAST KEEPING IT DRY FOR
NOW INTO NEXT WEEKEND.
&&
.AVIATION...
SHRAS/TSRAS ALREADY BEGINNING TO DEVELOP ACROSS INTERIOR SECTIONS OF
PALM BEACH...BROWARD...AND MIAMI-DADE COUNTIES EARLY THIS AFTERNOON.
THIS ACTIVITY WILL CONTINUE THROUGH THE LATE AFTERNOON AND EARLY
EVENING HOURS MUCH LIKE YESTERDAY. LATEST HRRR DEPICTS FURTHER
ACTIVITY DEVELOPING ACROSS THE INTERIOR OVER THE NEXT FEW HOURS AND
PUSHING EAST AS A RESULT OF THE GULF BREEZE THAT IS ALREADY WELL
ESTABLISHED. PLACED VCTS AT ALL EAST COAST TERMINAL SITES EXCEPT FOR
KTMB THROUGH THE EARLY EVENING HOURS. ACTIVITY SHOULD QUICKLY
DIMINISH WITH LOSS OF HEATING. FLOW SHOULD THEN GENERALLY BE
SOUTHERLY AND LIGHT OVERNIGHT.
&&
.MARINE...
TRANQUIL WIND AND SEAS WILL CONTINUE THROUGH THE WEEKEND OUTSIDE
OF ISOLATED STRONG CONVECTION. A COLD FRONT WILL MOVE ACROSS THE
SOUTH FLORIDA WATERS LATE MONDAY WITH STRONG HIGH PRESSURE
BUILDING BEHIND THE FRONT WITH INCREASING WIND AND SEAS MONDAY
NIGHT INTO MID WEEK.
&&
.FIRE WEATHER...
NO PROBLEMS OR CONCERNS WITH AMPLE TROPICAL MOISTURE THROUGH MONDAY.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 74 86 73 85 / 30 50 30 30
FORT LAUDERDALE 77 86 74 85 / 30 50 20 50
MIAMI 76 87 75 87 / 30 40 20 50
NAPLES 73 87 73 85 / 20 20 20 20
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
DISCUSSION/MARINE/FIRE...30/KOB
AVIATION/RADAR...10/CD
AREA FORECAST DISCUSSION
NWS PEACHTREE CITY GA
139 PM EDT SAT MAY 11 2013
.PREV DISCUSSION... /ISSUED 1045 AM EDT SAT MAY 11 2013/
UPDATE...
COLD FRONT IS CURRENTLY SITUATED FROM THE EASTERN GREAT LAKES
THROUGH THE MIDDLE ATLANTIC TO THE CENTRAL GULF COAST. THE FRONT
WILL CONTINUE TO MOVE EASTWARD THROUGH THE DAY AND THROUGH THE
REMAINDER OF THE CWFA THIS EVENING/OVERNIGHT.
EARLIER ADJUSTMENTS TO THE GRIDS INCLUDED SOME FINE TUNING OF THE
CLOUD COVER...POPS...AND HOURLY TEMPS/DEWPOINTS. MAX TEMPS LOOK
GOOD FOR NOW. MAIN FORECAST PROBLEM OF THE DAY WILL BE POPS.
SIGNIFICANT CLOUD COVER WILL HELP KEEP SURFACE INSTABILITY
MARGINAL UNDERCUTTING SURFACE HEATING. IN ADDITION...CONVECTION
ALONG THE GULF COAST MAY DISRUPT THE MOISTURE FLOW NORTHWARD.
NAM...GFS...ETC DONT HAVE A REALLY GOOD HANDLE OF THE GULF
CONVECTION. HOWEVER...THE LATEST RUN OF THE HRRR SEEMS TO HANDLE
THE CONVECTION REASONABLY. DO THINK SCT STORMS WILL DEVELOP ALONG
THE FRONT LATER IN THE AFTERNOON...MOSTLY SHOWERS WITH A FEW
THUNDERSTORMS. MAY END UP HAVING TO REDUCE POPS IN THE SOUTH TO
CHANCE...IF THEY GULF CONVECTION CONTINUES TO HOLD TOGETHER.
PREV DISCUSSION... /ISSUED 747 AM EDT SAT MAY 11 2013/
PREV DISCUSSION... /ISSUED 447 AM EDT SAT MAY 11 2013/
SHORT TERM /TODAY THROUGH SUNDAY/...
CURRENT SATELLITE LOOP SHOWS A LARGE MOISTURE PLUME EXTENDING FROM
THE NEW ENGLAND STATES...DOWN THE EASTERN SEABOARD...AND OVER TO THE
TX GULF COAST. THERE IS A NICE AREA OF ENHANCED SHOWERS AND ISOLATED
THUNDERSTORMS ACROSS TN AND AL BUT THIS PRECIPITATION IS NOT
EXPECTED TO MAKE IT INTO GA UNTIL LATER THIS MORNING INTO THIS
AFTERNOON. THE ACTUAL FRONT ASSOCIATED WITH THIS MOISTURE PLUME IS
BACK ACROSS TN NEAR MEMPHIS AND IT IS MOVING SLOWLY EAST. THIS FRONT
IS EXPECTED TO PUSH INTO NW GA BY 18Z TODAY AND MOVE SOUTH AND EAST
THROUGH THE SHORT TERM. IT SHOULD FINALLY PUSH OFF THE GA COAST BY
18Z SUN. AS THIS FRONT MOVES INTO THE AREA IT WILL BRING INCREASED
MOISTURE AND ACT AS A CATALYST FOR SHRA/TSRA DEVELOPMENT TODAY AND
TONIGHT. INSTABILITIES INCREASE TODAY WITH CAPES GETTING INTO THE
1000-1500 J/KG RANGE AND LIS GETTING DOWN INTO THE -1 TO -3 RANGE BY
18Z-00Z. SHEAR IS EXPECTED TO BE VERY WEAK AND LAPSE RATES ARE NOT
THAT IMPRESSIVE EITHER SO NOT EXPECTING ANY SEVERE STORMS TODAY.
ONCE THIS FRONT MOVES EAST OF THE AREA...A MUCH DRIER AIRMASS MOVES
IN WITH DEWPOINTS IN THE UPPER 30S TO LOWER 40S EXPECTED BY 18Z SUN.
01
LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
GFS/ECMWF MODEL GUIDANCE ARE IN GOOD AGREEMENT WITH A BROAD UPPER
UPPER LEVEL TROUGH MOVING THROUGH THE EASTERN U.S. THROUGH MON.
SURFACE HIGH PRESSURE WILL BUILD INTO GA WITH GENERALLY CLEAR
SKIES AND VERY DRY AND COOL AIR ALLOWING TEMPERATURES TO PLUNGE
ONCE AGAIN. AT THIS TIME SUN NIGHT MINS SHOULD BE FROM 10-15
DEGREES BELOW NORMAL WHILE MON MAXES WILL BE AROUND 10 DEGREES
BELOW NORMAL. A RAPID WARM-UP IS EXPECTED TUE THROUGH THU AS AN
UPPER LEVEL RIDGE DEVELOPS AND MOVES INTO THE SOUTHEAST U.S. MIN
AND MAX TEMPERATURES DURING THIS PERIOD WILL RETURN TO NEAR OR A
FEW DEGREES ABOVE NORMAL. THE GFS AND ECMWF MODELS BEGIN TO DIFFER
IN THEIR SOLUTIONS FOR THE END OF THE WEEK. THE GFS DEPICTS A MORE
ORGANIZED COLD FRONT MOVING THROUGH THE TN VALLEY THU NIGHT AND
FRI WHILE THE ECMWF HAS A WEAK PRESSURE PATTERN ALOFT. WILL GO
WITH THE GFS FOR NOW INDICATING ISOLATED TO SCATTERED TSTMS WITH
THE DIURNAL HEATING ON THU BECOMING MORE INFLUENCED BY THE
APPROACHING FRONT ON FRIDAY.
16
&&
.AVIATION...
18Z UPDATE...
COLD FRONT CURRENTLY ACROSS CENTRAL AL WILL MOVE ACROSS THE METRO
AREA LATER THIS EVENING. A WIND SHIFT TO THE NW SHOULD OCCUR JUST
BEFORE 06Z. WINDS MAY GUST TO AROUND 20 KT TOMORROW AFTERNOON AT
KATL. SCT SHRA EXPECTED FOR THE REMAINDER OF THE AFTERNOON TO
SKIRT THE AIRPORT. BEST CHANCE FOR THUNDER SEEMS TO BE FROM 22Z TO
00Z. VFR CONDITIONS EXPECTED ON MONDAY.
//ATL CONFIDENCE...18Z UPDATE...
MEDIUM CONFIDENCE ON TSRA TIMING AND CIGS THIS AFT/EVE. HIGH
CONFIDENCE REMAINING ELEMENTS/TIMES.
NLISTEMAA
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 79 56 77 43 / 50 30 5 0
ATLANTA 76 55 73 46 / 50 30 5 0
BLAIRSVILLE 72 49 67 38 / 40 20 10 0
CARTERSVILLE 75 53 72 41 / 40 20 5 0
COLUMBUS 79 59 78 47 / 60 40 10 0
GAINESVILLE 74 54 72 44 / 40 20 5 0
MACON 81 58 80 44 / 60 50 10 0
ROME 75 53 73 40 / 40 20 5 0
PEACHTREE CITY 75 54 74 38 / 50 30 5 0
VIDALIA 85 65 83 50 / 50 50 20 0
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS DES MOINES IA
1240 PM CDT SAT MAY 11 2013
.UPDATE...
ISSUED AT 957 AM CDT SAT MAY 11 2013
UPDATING ZONES TO REFLECT CHANCE OF SPRINKLES ACROSS THE NORTHEAST
TODAY. THOUGH MOISTURE REMAINS LIMITED...SECOND COLD FRONT WITH
COLD AIR ALOFT WILL INCREASE CU FIELD NORTHEAST AND POSSIBLY
PRODUCE A FEW LIGHT SHOWERS ALONG WITH GUSTY WINDS THIS AFTERNOON.
&&
.SHORT TERM.../TODAY/
ISSUED AT 325 AM CDT SAT MAY 11 2013
MAIN CONCERNS TODAY WILL BE SUBTLE PRECIP TRENDS AND WIND. UPPER
LEVEL TROUGH...INCLUDING POTENT ND/MN PV ANOMALY...CONTINUES TO
ADVANCE TOWARD THE GREAT LAKES EARLY THIS MORNING. WIDELY SCATTERED
LIGHT SHOWERS HAVE DEVELOPED AHEAD OF THIS FEATURE INTO IA AND ARE
PRIMARILY THERMODYNAMICALLY FORCED. LATEST RAP ANALYSIS SHOWS NICE
COLD FRONT ALOFT WITH RELATIVELY HIGHER BASED THETA-E ADVECTION AND
FRONTOGENETICAL FORCING. RESULTANT PRECIP IS HIGH BASED...TYPICALLY
7K FT OR HIGHER...AND STRUGGLING TO REACH THE GROUND MUCH.
EXTRAPOLATION SUGGESTS WHAT PRECIP THERE IS WILL ADVANCE SOUTH AND
EAST EXITING SE TOWARD 12Z. PRECIP OVER NRN MN IS NOT EXPECTED TO
AFFECT OUR FORECAST AREA BY AFTERNOON DUE TO TRAJECTORIES AND
INCREASING SUBSIDENCE. SOUNDINGS SHOW SOME POTENTIAL FOR SURFACE
BASED REDEVELOPMENT BUT ADEQUATE MOISTURE IS CERTAINLY QUESTIONABLE.
08Z SURFACE ANALYSIS SHOWS INITIAL WIND SHIFT/TROUGH ALONG
CARROLL-WEBSTER CITY-MASON CITY LINE WITH TRUE COLD FRONT SEEMING TO
LACK BEHIND JUST REACHING IA/MN BORDER. MOS GUIDANCE AND SOUNDINGS
SUGGEST WIND WILL INCREASE WITH MIXING TODAY...APPROACHING SUSTAINED
ADVISORY CRITERIA /26 KTS/ NORTHEAST. SOUNDINGS DEPICT MIXING TO
2KM OR MORE BY AFTERNOON WITH MIXED LAYER WINDS SUGGESTING GUSTS
INTO THE LOW 30S /KTS/ NE THIRD.
MAX TEMPS ARE GENERALLY AT OR BELOW MOS GUIDANCE EVEN WITH THIS DEEP
MIXING. THESE SOUNDINGS STRUGGLE TO REACH MOS...LIKELY DUE TO
INFLUENCE OF CLIMO. DEWPOINTS WILL ALSO BE QUITE LOW...DROPPING INTO
THE 20S DUE TO UPSTREAM AIRMASS AND MIXING. MODEL SKIN DEWPOINTS
SEEM TOO HIGH...LIKELY OVERDONE DUE TO EVAPOTRANSPIRATION BEING
BEHIND SCHEDULE.
.LONG TERM.../TONIGHT THROUGH FRIDAY/
ISSUED AT 325 AM CDT SAT MAY 11 2013
A SOMEWHAT HIGH AMPLITUDE UPPER AIR PATTERN INITIALLY GIVES WAY TO
A MORE ZONAL...OR AT LEAST A LOWER AMPLITUDE UPPER PATTERN BY
THE MIDDLE OF NEXT WEEK. AN UPPER RIDGE OVER THE PACIFIC NORTHWEST
BUILDS INTO THE NORTHERN PLAINS BY TUESDAY. AS IT RIDGE MOVES
EAST...IT IS FLATTENED BY A SHORTWAVE MOVING OVER THE RIDGE ACROSS
SOUTHERN CANADA. MEANWHILE...AN OLD UPPER LOW INITIALLY OVER
NORTHWEST MEXICO EJECTS INTO THE CENTRAL PLAINS AND GETS ABSORBED
INTO THE WESTERLIES. THE SHORT RANGE MODELS ARE IN FAIR AGREEMENT
WITH THE EVALUATION OF THE PATTERN THROUGH TUESDAY. AFTER
TUESDAY...THE 00Z GFS/ECMWF START TO DIVERGE WITH THE DETAILS OF
THE UPPER PATTERN AND ASSOCIATED SURFACE REFLECTION. THE 00Z GFS
HAS MORE AMPLITUDE ALLOWING THE SURFACE FRONT TO MOVE SOUTH OF
IOWA BY MIDWEEK. THE ECMWF HAVING A FLATTER LOOKING PATTERN NEVER
PUSHES THE BOUNDARY THROUGH THE STATE BEFORE LIFTING IT BACK NORTH
LATE IN THE WEEK.
THE SHORT RANGE MODELS ARE IN GOOD AGREEMENT CONCERNING THE
POSITION OF THE POLAR SURFACE HIGH OVER THE MISSOURI VALLEY BY 12Z
SUNDAY. IT WOULD APPEAR THAT A GOOD RADIATION COOLING SCENARIO
SHOULD OCCUR OVER WESTERN IOWA SUNDAY MORNING. WITH LIGHT WINDS
AND LOWS APPROACHING FREEZING...WILL ISSUE A FROST ADVISORY FOR
PART OF WESTERN AND NORTHERN SECTIONS OF THE FORECAST AREA. SOME
CONCERN ABOUT LOW DEWPOINTS...BUT WHERE THE WIND IS VERY
LIGHT...THERE SHOULD BE ENOUGH FROST FORMATION TO WARRANT
ADVISORY.
NEXT UP WILL BE THE RAPID WARM UP EARLY NEXT WEEK AS BEFORE MENTION
UPPER RIDGE MOVES ACROSS THE NORTHERN CONUS. MODELS ARE IN GOOD
AGREEMENT WITH VERY WARM 850 MB TEMPERATURES ON TUESDAY IN THE
WARM SECTOR AHEAD OF THE APPROACHING COLD FRONT. BASICALLY USED THE
PREVIOUS FORECAST FOR HIGHS WHICH LOOK ON TARGET.
THE PATTERN LOOKS MORE ACTIVE CONCERNING THUNDERSTORMS FROM THE
MIDDLE OF NEXT WEEK THROUGH THE END OF THE FORECAST PERIOD. THERE
SHOULD BE AN WEST TO EAST BOUNDARY IN THE AREA WHICH CLIMATOLOGICALLY
SUPPORTS THUNDERSTORM CHANCES.
&&
.AVIATION...11/18Z
ISSUED AT 1236 PM CDT SAT MAY 11 2013
WINDS CONTINUE TO BE THE MAIN CONCERN THIS AFTERNOON WTIH GUSTS
EXCEEDING 35 KTS ACROSS THE AREA FOR THE NEXT SEVERAL HOURS. CIGS
WILL REMAIN VFR BUT EXPECT HIGHER GUSTS AT TIMES NEAR CU FIELD. AS
HIGH BUILDS INTO THE REGION TONIGHT WINDS WILL RELAX AND DROP OFF
SIGNIFICANTLY AFT 01Z MOST AREAS. SOME INCREASE AGAIN IN WINDS AFT
15-16Z SUNDAY WITH MIXING AND A FEW CUMULUS OVER THE NORTHEAST AT
THAT TIME.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...
FROST ADVISORY FROM 3 AM TO 9 AM CDT SUNDAY FOR AUDUBON-CALHOUN-
CARROLL-CASS-CERRO GORDO-CRAWFORD-EMMET-GREENE-GUTHRIE-HANCOCK-
HUMBOLDT-KOSSUTH-PALO ALTO-POCAHONTAS-SAC-WEBSTER-WINNEBAGO-
WORTH-WRIGHT.
&&
$$
UPDATE...REV
SHORT TERM...SMALL
LONG TERM...JOHNSON
AVIATION...REV
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1132 AM MDT SAT MAY 11 2013
.UPDATE...
ISSUED AT 947 AM MDT SAT MAY 11 2013
JUST COMPLETED A MINOR UPDATE...MAINLY FOR TEMPERATURES. CURRENT
TEMPERATURE TRENDS SUPPORT NEAR TO SLIGHTLY WARMER THAN CURRENT
FORECAST. HRRR AND RUC MATCHING UP WELL WITH REALITY AND SUPPORT
DOING THIS AS WELL. ADJUSTED ACCORDINGLY WITH MOST ADJUSTMENT IN
THE FAR SOUTHERN AND SOUTHWEST LOCATIONS.
ALSO PER CURRENT TRENDS AND NEWEST MODEL DATA THAT IS ROLLING
IN...ADJUSTED SKY COVER AND WINDS NOT ONLY FOR TODAY BUT ALSO INTO
TOMORROW. NEWEST MODEL DATA IS ALSO SUPPORTING CURRENT
PRECIPITATION FORECAST THROUGH TOMORROW AND INITIAL IMPRESSIONS
ARE THAT LITTLE IF ANY CHANGES WILL BE MADE TO THE CURRENT POP/WX
FORECAST.
&&
.SHORT TERM...(TODAY THROUGH MONDAY NIGHT)
ISSUED AT 200 AM MDT SAT MAY 11 2013
TODAY-TONIGHT...COLD FRONT CURRENTLY MOVING SOUTH ACROSS THE AREA.
SHOULD SEE SOME GUSTY NORTH TO NORTHEAST WINDS UP TO 25 MPH THIS
MORNING BEFORE SFC HIGH MOVES IN DECREASING WINDS RATHER QUICKLY
THIS AFTERNOON. WINDS BECOME SOUTH/SOUTHWESTERLY TONIGHT. A
WEATHER DISTURBANCE MOVES INTO FAR EASTERN COLORADO LATE THIS
AFTERNOON CONTINUING SOUTH/SOUTHEAST EARLY TONIGHT ACROSS THE FAR
SOUTHWEST AND WESTERN PARTS OF THE AREA. HAVE THUNDERSTORMS
MENTIONED IN THESE AREAS. AFTER MIDNIGHT THERE ARE DISCREPANCIES
IN WHETHER OR NOT ANOTHER WEAK DISTURBANCE MOVES ACROSS THE FAR
EASTERN ZONES...THE GFS HAS IT FURTHER EAST OUT OF THE AREA WHILE
THE NAM HAS IT GRAZING PARTS OF OUR AREA. CONSISTENCY THE PAST FEW
DAYS WOULD FAVOR THE NAM SOLUTION AND AS A RESULT HAVE KEPT SOME
SMALL POPS FOR THE EASTERN 1/3-1/4 OF THE AREA. HIGHS TODAY MID
60S TO AROUND 70. LOWS TONIGHT UPPER 30S NEAR FLAGLER WITH 40S
ELSEWHERE.
SUNDAY-SUNDAY NIGHT...MODELS CONTINUE TO HAVE DISCREPANCIES AS TO
WHETHER OR NOT WEATHER DISTURBANCES MOVE THROUGH THE NORTHWEST
FLOW ALOFT. GFS HAS ONE MOVE THROUGH DURING THE AFTERNOON WHILE
THE NAM DOES NOT. FOR NOW NO CHANGES PLANNED. UPPER RIDGE STARTS
TO MOVE IN DURING THE NIGHT SHUNTING ANY APPRECIABLE MOISTURE AND
CONVECTIVE THREAT EAST OF THE AREA. 850 TEMPERATURES WARM 12-14F
SUPPORTING HIGHS IN THE UPPER 70S TO LOW 80S WHICH IS ALSO
SUPPORTED BY BETTER PERFORMING BIAS CORRECTED GRIDS AND MAV/MET
GUIDANCE. NOT MUCH CHANGE NEEDED FROM PREVIOUS FORECAST. LOWS MID
40S TO LOW 50S.
MONDAY-MONDAY NIGHT...UPPER RIDGE CONTINUES TO SLOWLY MOVE EAST
TOWARD THE AREA. 850 TEMPERATURES WARM ANOTHER 8-13F FROM SUNDAYS
VALUES SUPPORTING HIGHS IN THE UPPER 80S WEST TO MID 90S EAST.
BIAS CORRECTED GRIDS AND MAV/MET GUIDANCE AVG A FEW DEGREES
COOLER. BLENDING THEM TOGETHER PRODUCES HIGHS IN THE MID TO UPPER
80S WEST...LOW TO MID 90S EAST. HAVENT GONE QUITE AS WARM AS 850
TEMPS SUPPORT ACROSS THE EASTERN 1/3 OF THE AREA FOR NOW BUT 96-97
DEGREES VERY POSSIBLE. THIS WOULD BREAK RECORD HIGHS FOR THE DATE
(SEE CLIMO SECTION BELOW). LOWS IN THE 50S.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 325 AM MDT SAT MAY 11 2013
MERIDIONAL FLOW BREAKS DOWN AS THE PERSISTENT RIDGE OVER THE WESTERN
UNITED STATES FLATTENS WITH A LOW CENTER MOVING EASTWARD ACROSS
SOUTHERN CANADA. THE COLD FRONT TRAILING BEHIND THAT LOW APPROACHES
THE CENTRAL HIGH PLAINS REGION ON TUESDAY AS A CUTOFF LOW THAT HAS
BEEN OVER NORTHERN MEXICO BEGINS TO LIFT OUT ACROSS THE SOUTHERN
PLAINS ON TUESDAY AND TUESDAY NIGHT. THE FRONT MOVES THROUGH THE
REGION EARLY WEDNESDAY WITH SHOWERS AND THUNDERSTORMS FORMING IN THE
VICINITY OF THE FRONT. THIS WILL BRING SOMEWHAT COOLER TEMPERATURES
TO THE REGION ON WEDNESDAY AND THURSDAY.
ZONAL FLOW BEGINS TO REAMPLIFY INTO A RIDGE OVER THE ROCKIES
THURSDAY AND FRIDAY AS THE NEXT UPPER TROUGH MOVES INTO THE WEST
COAST. TEMPERATURE ARE EXPECTED TO RISE THROUGH THE END OF THE WEEK
AND INTO THE WEEKEND WITH THE POSSIBILITY OF ISOLATED TO SCATTERED
SHOWERS AND THUNDERSTORMS EACH DAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1128 AM MDT SAT MAY 11 2013
VFR CONDITIONS THROUGH THE PERIOD. WINDS WILL BE VARIABLE AND
SHIFTING THROUGH THE PERIOD. AFTER 06Z SHOWERS WILL GET NEAR KMCK.
AT THIS TIME CHOSE TO HANDLE THAT WITH VCSH.
&&
.CLIMATE...
ISSUED AT 200 AM MDT SAT MAY 11 2013
RECORD HIGH TEMPERATURES MONDAY:
HILL CITY....96 (1915)
MCCOOK.......95 (1962)
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...BULLER
SHORT TERM...99
LONG TERM...LOCKHART
AVIATION...BULLER
AREA FORECAST DISCUSSION
NWS CARIBOU ME
639 PM EDT SAT MAY 11 2013
.SYNOPSIS...
A COLD FRONT WILL APPROACH LATER TONIGHT AND CROSS THE REGION ON
SUNDAY WITH ADDITIONAL AFTERNOON SHOWERS. COLDER AND DRIER AIR WILL
FOLLOW FOR EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH SUNDAY/...
0630 PM UPDATE: BEEFED UP POPS TO CATEGORICAL REGION WIDE FOR
EARLY THIS EVENING AS ADDITIONAL SHOWERS ARE MOVING IN AT THIS
HOUR. ALSO MADE SOME ADJUSTMENTS TO QPF FOR THIS
EVENING..GENERALLY UPPING AMOUNTS SLIGHTLY ACROSS MOST OF THE
AREA. FINALLY, SOME MINOR CHANGES TO WINDS AND TEMPERATURES FOR
THE EARLY TO MID EVENING PERIOD. NUDGED BOTH TEMPERATURES AND WINDS DOWN
SLIGHTLY BASED ON CURRENT OBSERVATIONS.
PREVIOUS DISCUSSION: MAIN CHALLENGES WILL BE TIMING OF RAIN
TONIGHT INTO SUNDAY AND TEMPERATURES.
FIRST AREA OF RAIN MOVING TO THE E INTO NEW BRUNSWICK WHILE SEND
AREA OF RAIN AND POSSIBLE TSTMS MOVING INTO SWRN AREAS ATTM PER
THE LATEST RADAR. THIS SECOND AREA OF RAIN WILL OVERSPREAD THE CWA
LATER THIS AFTERNOON INTO EARLY TONIGHT. 12Z UA INDICATED A STRONG
40KT JETLET AT 700MBS ACROSS ONTARIO AND WRN NYS. THIS AREA OF
FORCING WAS PICKED UP BY THE GFS AND CANADIAN GEM. THEREFORE, A
BLEND OF THESE 2 MODELS WERE USED INTO EARLY TONIGHT AS THEY SHOW
A SIGNIFICANT AREA OF RAIN MOVING ACROSS THE REGION. ATMOSPHERE
LOOKS LIKE IT STABILIZES AFTER 22Z AND THEREFORE CUT BACK ON THE
MENTION OF TSTMS FOR OUR CWA. THE LATEST RAP FROM THE SPC MESO-
ANALYSIS PAGE INDICATED SOME POSSIBLE TSTMS EDGING INTO GYX/S WRN
ZONES THIS AFTERNOON AND THEN WEAKENING BY 22Z OR SO. A BLEND OF
THE NERFC/GFS AND SREF WAS USED FOR THE QPF WHICH SHOWED AN
ADDITIONAL 0.15-0.30 THROUGH 06Z AND THEN RAIN END AS THE BEST
FORCING EXITS INTO NEW BRUNSWICK. ADDED FOG FOR ALL THE CWA
OVERNIGHT W/THE MOST DENSE FOG FROM MLT REGION ON SOUTH.
TEMPERATURES WILL BE HELD UP TONIGHT AND FOLLOWED A BLEND OF THE
NAM12 AND REGIONAL GEM FOR TONIGHT`S LOWS SHOWING UPPER 40S OUT
WEST TO LOW TO MID 50S EASTERN AND CENTRAL AREAS.
FOR SUNDAY, DRY W/SOME FOG TO START AND THEN ANOTHER BATCH OF
SHOWERS EXPECTED BY MIDDAY DUE TO THE COLD FRONT APCHG FROM THE W.
STAYED W/A GEM/GFS BLEND FOR TIMING OF THE SHOWERS USING THE MID
LEVEL FORCING FOR THE QPF WHICH SHOWED ANOTHER .10-.20, MAINLY
NORTHERN AND CENTRAL AREAS. HELD BACK THE TEMPERATURES FROM PREVIOUS
THINKING AND LEANED W/LOWER 60S NORTH AND MID 60S CENTRAL AND
DOWNEAST AS CAA LOOKS TO TAKE HOLD IN THE AFTERNOON. TSTM
POTENTIAL LOOKS TO BE LESS LIKELY ESPECIALLY ACROSS THE DOWNEAST
AND COAST DUE TO THE ONSHORE FLOW. BEST CHANCES IF ANY WILL BE
ACROSS THE NORTHERN AND WESTERN AREAS DUE TO SOME ELEVATED
INSTABILITY. ATTM, KEPT ISOLATED THUNDER IN THERE FOR CONTINUITY.
MIDNIGHT CREW CAN ASSESS THIS FURTHER TONIGHT.
&&
.SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY/...
THE FIRST PART OF THE PERIOD WILL BEGIN WITH SHOWERS ACROSS THE
NORTHERN AND CENTRAL PARTS OF THE REGION SUNDAY NIGHT. THESE
SHOWERS ARE DUE TO A BOUNDARY THAT WILL MOVE FROM WEST TO EAST.
THE BEST LIFT LOOKS TO BE ACROSS THE NORTH. ONCE THIS FRONTAL
BOUNDARY PUSHES THROUGH THE REGION TEMPERATURES WILL COOL OFF FOR
MONDAY WITH HIGHS IN THE 50S NORTH AND THE UPPER 50S TO LOWER 60S
SOUTH. AS THE UPPER LEVEL TROUGH MOVES EAST THE 12Z GFS IS TRYING
TO CLOSE THE TROUGH TO THE NORTH WHILE THE 12Z NAM/00Z ECMWF
CONTINUE TO DEVELOP THE CLOSED LOW AROUND THE BASE OF THE TROUGH.
RIGHT NOW WILL LEAN WITH THE SURFACE LOW DEVELOPS TRACKING MAINLY
EAST OF THE AREA LATE TUESDAY INTO TUESDAY NIGHT. MAIN AFFECT TO
THE FORECAST FOR THIS PERIOD WILL BE THE INCREASE IN CLOUDS
COVERAGE WITH HIGHEST COVERAGE SEEN ACROSS THE EASTERN AND
SOUTHEASTERN PARTS OF THE REGION.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
BOTH MEDIUM RANGE MODELS ARE IN GENERAL AGREEMENT IN THE TUESDAY
NIGHT THROUGH THROUGH SUNDAY TIME FRAME. THE FORECAST FOR
WEDNESDAY CONTINUES TO BE DRY. MOISTURE INCREASES WEDNESDAY
NIGHT...AHEAD OF THE NEXT SYSTEM EXPECTED TO MOVE THROUGH THE
AREA...BRINGING A CHANCE OF RAIN MAINLY ON THURSDAY. AT THIS POINT
IT APPEARS WE MAY HAVE A BREAK BETWEEN SYSTEMS ON FRIDAY HOWEVER
LATE FRIDAY INTO SATURDAY SHOULD SEE RAIN CHANCES INCREASE ACROSS
THE REGION ONCE AGAIN. SEASONAL TEMPERATURES ARE EXPECTED THROUGH
THE PERIOD WITH SOME DAYS A LITTLE ABOVE NORMAL AND OTHERS WITH
READINGS A LITTLE BELOW.
&&
.AVIATION /00Z SUNDAY THROUGH THURSDAY/...
NEAR TERM: IFR INTO SUNDAY MORNING AND THEN CONDITIONS GO TO MVFR
ESPECIALLY NORTHERN TERMINALS.
SHORT TERM: MOST TAF SITES WILL STAY VFR THROUGH THE PERIOD
EXCEPT FOR SUNDAY NIGHT WITH HEAVIER SHOWERS THERE COULD BE
PERIODS OF MVFR OR IFR.
&&
.MARINE...
NEAR TERM: DECIDED TO TRANSITION THE SCA TO HAZARDOUS SEAS INTO
SUNDAY. WAVES ARE CLIMBING TO 6 ATTM W/A SWELL GENERATED. WILL
CARRY THE MENTION OF THE SWELL INTO SUNDAY. WINDS ARE BELOW SCA
AND EXPECTING THEM TO STAY BELOW INTO SUNDAY. FOLLOWED THE
NAM12/GFS40 BLEND FOR THE WINDS AND FOLLOWED CLOSELY W/THE
MIDNIGHT CREW`S WAVE HEIGHTS OF 4-7 FT.
SHORT TERM: SCA CONDITIONS SUBSIDE BY THE SHORT TERM PERIOD.
KEPT CONSISTENCY WITH LAST NIGHTS SHIFT FOR WAVE AND WIND GRIDS.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
MARINE...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 4 PM EDT SUNDAY
FOR ANZ050>052.
&&
$$
NEAR TERM...FITZSIMMONS/HEWITT
SHORT TERM...JORDAN
LONG TERM...RUNYAN
AVIATION...FITZSIMMONS/HEWITT/JORDAN
MARINE...FITZSIMMONS/HEWITT/JORDAN
AREA FORECAST DISCUSSION
NWS CARIBOU ME
357 PM EDT SAT MAY 11 2013
.SYNOPSIS...
A COLD FRONT WILL APPROACH LATER TONIGHT AND CROSS THE REGION ON
SUNDAY WITH ADDITIONAL AFTERNOON. COLDER AND DRIER AIR WILL
FOLLOW FOR EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH SUNDAY/...
MAIN CHALLENGES WILL BE TIMING OF RAIN TONIGHT INTO SUNDAY AND
TEMPERATURES.
FIRST AREA OF RAIN MOVING TO THE E INTO NEW BRUNWICK WHILE SEND
AREA OF RAIN AND POSSIBLE TSTMS MOVING INTO SWRN AREAS ATTM PER
THE LATEST RADAR. THIS SECOND AREA OF RAIN WILL OVERSPREAD THE CWA
LATER THIS AFTERNOON INTO EARLY TONIGHT. 12Z UA INDICATED A STRONG
40KT JETLET AT 700MBS ACROSS ONTARIO AND WRN NYS. THIS AREA OF
FORCING WAS PICKED UP BY THE GFS AND CANADIAN GEM. THEREFORE, A
BLEND OF THESE 2 MODELS WERE USED INTO EARLY TONIGHT AS THEY SHOW
A SIGNIFICANT AREA OF RAIN MOVING ACROSS THE REGION. ATMOSPHERE
LOOKS LIKE IT STABILIZES AFTER 22Z AND THEREFORE CUT BACK ON THE
MENTION OF TSTMS FOR OUR CWA. THE LATEST RAP FROM THE SPC MESO-
ANALYSIS PAGE INDICATED SOME POSSIBLE TSTMS EDGING INTO GYX/S WRN
ZONES THIS AFTERNOON AND THEN WEAKENING BY 22Z OR SO. A BLEND OF
THE NERFC/GFS AND SREF WAS USED FOR THE QPF WHICH SHOWED AN
ADDITIONAL 0.15-0.30 THROUGH 06Z AND THEN RAIN END AS THE BEST
FORCING EXITS INTO NEW BRUNSWICK. ADDED FOG FOR ALL THE CWA
OVERNIGHT W/THE MOST DENSE FOG FROM MLT REGION ON SOUTH.
TEMPERATURES WILL BE HELD UP TONIGHT AND FOLLOWED A BLEND OF THE
NAM12 AND REGIONAL GEM FOR TONIGHT`S LOWS SHOWING UPPER 40S OUT
WEST TO LOW TO MID 50S EASTERN AND CENTRAL AREAS.
FOR SUNDAY, DRY W/SOME FOG TO START AND THEN ANOTHER BATCH OF
SHOWERS EXPECTED BY MIDDAY DUE TO THE COLD FRONT APCHG FROM THE W.
STAYED W/A GEM/GFS BLEND FOR TIMING OF THE SHOWERS USING THE MID
LEVEL FORCING FOR THE QPF WHICH SHOWED ANOTHER .10-.20, MAINLY
NORTHERN AND CENTRAL AREAS. HELD BACK THE TEMPERATURES FROM PREVIOUS
THINKING AND LEANED W/LOWER 60S NORTH AND MID 60S CENTRAL AND
DOWNEAST AS CAA LOOKS TO TAKE HOLD IN THE AFTERNOON. TSTM
POTENTIAL LOOKS TO BE LESS LIKELY ESPECIALLY ACROSS THE DOWNEAST
AND COAST DUE TO THE ONSHORE FLOW. BEST CHANCES IF ANY WILL BE
ACROSS THE NORTHERN AND WESTERN AREAS DUE TO SOME ELEVATED
INSTABILITY. ATTM, KEPT ISOLATED THUNDER IN THERE FOR CONTINUITY.
MIDNIGHT CREW CAN ASSESS THIS FURTHER TONIGHT.
&&
.SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY/...
THE FIRST PART OF THE PERIOD WILL BEGIN WITH SHOWERS ACROSS THE
NORTHERN AND CENTRAL PARTS OF THE REGION SUNDAY NIGHT. THESE
SHOWERS ARE DUE TO A BOUNDARY THAT WILL MOVE FROM WEST TO EAST.
THE BEST LIFT LOOKS TO BE ACROSS THE NORTH. ONCE THIS FRONTAL
BOUNDARY PUSHES THROUGH THE REGION TEMPERATURES WILL COOL OFF FOR
MONDAY WITH HIGHS IN THE 50S NORTH AND THE UPPER 50S TO LOWER 60S
SOUTH. AS THE UPPER LEVEL TROUGH MOVES EAST THE 12Z GFS IS TRYING
TO CLOSE THE TROUGH TO THE NORTH WHILE THE 12Z NAM/00Z ECMWF
CONTINUE TO DEVELOP THE CLOSED LOW AROUND THE BASE OF THE TROUGH.
RIGHT NOW WILL LEAN WITH THE SURFACE LOW DEVELOPS TRACKING MAINLY
EAST OF THE AREA LATE TUESDAY INTO TUESDAY NIGHT. MAIN AFFECT TO
THE FORECAST FOR THIS PERIOD WILL BE THE INCREASE IN CLOUDS
COVERAGE WITH HIGHEST COVERAGE SEEN ACROSS THE EASTERN AND
SOUTHEASTERN PARTS OF THE REGION.
&&
.LONG TERM /TUESDAY NIGHT THROUGH FRIDAY/...
BOTH MEDIUM RANGE MODELS ARE IN GENERAL AGREEMENT IN THE TUESDAY
NIGHT THROUGH THROUGH SUNDAY TIME FRAME. THE FORECAST FOR
WEDNESDAY CONTINUES TO BE DRY. MOISTURE INCREASES WEDNESDAY
NIGHT...AHEAD OF THE NEXT SYSTEM EXPECTED TO MOVE THROUGH THE
AREA...BRINGING A CHANCE OF RAIN MAINLY ON THURSDAY. AT THIS POINT
IT APPEARS WE MAY HAVE A BREAK BETWEEN SYSTEMS ON FRIDAY HOWEVER
LATE FRIDAY INTO SATURDAY SHOULD SEE RAIN CHANCES INCREASE ACROSS
THE REGION ONCE AGAIN. SEASONAL TEMPERATURES ARE EXPECTED THROUGH
THE PERIOD WITH SOME DAYS A LITTLE ABOVE NORMAL AND OTHERS WITH
READINGS A LITTLE BELOW.
&&
.AVIATION /19Z SATURDAY THROUGH THURSDAY/...
NEAR TERM: IFR INTO SUNDAY MORNING AND THEN CONDITIONS GO TO MVFR
ESPECIALLY NORTHERN TERMINALS.
SHORT TERM: MOST TAF SITES WILL STAY VFR THROUGH THE PERIOD
EXCEPT FOR SUNDAY NIGHT WITH HEAVIER SHOWERS THERE COULD BE
PERIODS OF MVFR OR IFR.
&&
.MARINE...
NEAR TERM: DECIDED TO TRANSITION THE SCA TO HAZARDOUS SEAS INTO
SUNDAY. WAVES ARE CLIMBING TO 6 ATTM W/A SWELL GENERATED. WILL
CARRY THE MENTION OF THE SWELL INTO SUNDAY. WINDS ARE BELOW SCA
AND EXPECTING THEM TO STAY BELOW INTO SUNDAY. FOLLOWED THE
NAM12/GFS40 BLEND FOR THE WINDS AND FOLLOWED CLOSELY W/THE
MIDNIGHT CREW`S WAVE HEIGHTS OF 4-7 FT.
SHORT TERM: SCA CONDITIONS SUBSIDE BY THE SHORT TERM PERIOD.
KEPT CONSISTENCY WITH LAST NIGHTS SHIFT FOR WAVE AND WIND GRIDS.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
MARINE...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 4 PM EDT
SUNDAY FOR ANZ050>052.
&&
$$
NEAR TERM...HEWITT
SHORT TERM...JORDAN
LONG TERM...RUNYAN
AVIATION...HEWITT/JORDAN
MARINE...HEWITT/JORDAN
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
500 PM EDT SAT MAY 11 2013
.SYNOPSIS...
A COLD FRONT CROSSES THE MID ATLANTIC TONIGHT FOLLOWED BY A
SECONDARY COLD FRONT SUNDAY EVENING. CANADIAN HIGH PRESSURE BUILDS
INTO THE REGION MONDAY AND MONDAY NIGHT BRINGING A VERY COOL
AIR FOR THE MIDDLE OF MAY...BEFORE SLIDING OFF THE COAST TUESDAY.
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
THE LATEST REGIONAL RADAR MOSAIC SHOWS ISOLATED TO SCATTERED SHOWERS
AND THUNDERSTORMS ACROSS THE REGION MARGINALLY UNSTABLE AIRMASS
(~1000 J/KG OF MLCAPE) ALONG WITH MODEST DEEP LAYER SHEAR (30-40KT
0-6KM). CURRENT GOES WATER VAPOR IMAGERY SHOWS A SHORTWAVE TROUGH
LIFTING NE ACROSS PA ALONG WITH STRONGER SYNOPTIC SCALE
DYNAMICS...HENCE ANY STORMS ACROSS THE LOCAL AREA HAVE STRUGGLED TO
ORGANIZE AND PERSIST. THIS TREND IS EXPECTED TO CONTINUE OVER THE
NEXT FEW HOURS BEFORE A JET STREAK OVER THE TENNESSEE VALLEY EJECTS
NE ACROSS THE REGION AHEAD OF A FRONTAL ZONE APPROACHING FROM THE
WEST.
THE LATEST RUC BRINGS THE JET ACROSS THE AREA DURING THE MID-EVENING
THROUGH EARLY OVERNIGHT HOURS. GIVEN THIS...A BAND OF LIKELY POPS
WILL BE FORECAST TO MOVE W-E OVER THE CWA. HOWEVER...QPF AMOUNTS
SHOULD BE RATHER MINIMAL. THUNDER WILL BE MAINTAINED THROUGH
MIDNIGHT TO ACCOUNT FOR ANY LINGERING INSTABILITY BEFORE
TRANSITIONING TO ONLY SHOWERS AFTER MIDNIGHT. LOW TEMPERATURES SHOULD
RANGE FROM THE LOW 50S NW...TO LOW 60S SE.
&&
.SHORT TERM /6 AM SUNDAY MORNING THROUGH TUESDAY/...
STEADY CAA COMMENCES SUNDAY AS THE COLD FRONT MOVES OFF THE COAST
SUNDAY MORNING AND HIGH PRESSURE BUILDS OVER THE MISSISSIPPI VALLEY.
THIS SHOULD PRODUCE A RATHER PLEASANT DAY WITH LOW-LEVEL THICKNESS
VALUES SUPPORTING HIGHS IN THE UPPER 60S N/NW...TO THE LOW/MID 70S
SE UNDER AN INCREASINGLY SUNNY SKY.
A SECONDARY COLD FRONT SWINGS THROUGH THE REGION SUNDAY NIGHT. THE
CONTINUATION OF STEADY CAA OVERNIGHT WILL DRIVE LOW TEMPERATURES
DOWN INTO THE UPPER 30S N/NW TO THE MID/UPPER 40S FAR SE UNDER A
CLEAR SKY. THERE SHOULD BE ENOUGH MIXING ALONG WITH DRY AIR/LOW
DEWPOINTS TO INHIBIT ANY FROST DEVELOPMENT IN THE COLDER SPOTS.
VERY COLD AIR ALOFT FOR MID-MAY ARRIVES MONDAY DRIVING 1000-500MB
THICKNESS VALUES DOWN TO AROUND 532-540DAM. A STRONG VORT MAX/PV MIN
DIVES AROUND THE BACK-SIDE OF THE PARENT TROUGH DURING THE
AFTERNOON. THIS ENERGY DROPPING INTO THE TROUGH WILL DROP 500MB
HEIGHTS TO -2 TO -3 ST DEV PER 11/12Z GEFS MEAN AT 00Z TUESDAY.
GIVEN THIS...A BKN SC DECK IS EXPECTED TO DEVELOP DURING THE
AFTERNOON. LOW AND MID LEVEL LAPSE RATES WILL BE RATHER STEEP...SO
THERE WILL BE A MINIMAL POTENTIAL OF SHOWERS WHEN COMBINED WITH THE
COLD AIR ALOFT AND MID/UPPER LEVEL ENERGY. HOWEVER...POPS WILL BE
LIMITED BELOW 15 PERCENT AT THIS TIME GIVEN THAT THE AIRMASS WILL BE
VERY DRY (SFC DEWPOINTS IN THE MID/UPPER 20S INLAND).
850MB TEMPERATURES DROP TO AROUND 0C MONDAY...WHICH IS AROUND -2 ST
DEV BELOW NORMAL PER 11/12Z GEFS MEAN. FULLY MIXED...AS EXPECTED
WILL RESULT IN HIGH TEMPERATURES RANGING FROM THE UPPER 50S N...TO
NEAR 65 FAR S...WHICH WOULD ALSO BE AROUND -2 ST DEV BELOW SEASONAL
MEANS. DAYTIME HIGHS MAY BE REACHED AROUND MIDDAY BEFORE DROPPING A
FEW DEGREES IN THE AFTERNOON AS CLOUD COVER INCREASES.
CANADIAN HIGH PRESSURE SETTLES OVER THE PIEDMONT MONDAY NIGHT INTO
TUESDAY MORNING. THE SKY SHOULD CLEAR MONDAY EVENING...WHICH WILL
EVENTUALLY RESULT IN A COOL START TO THE DAY TUESDAY. FORECAST LOWS
RANGE FROM THE MID 30S OVER THE PIEDMONT AND E/S-CENTRAL VA COASTAL
PLAIN TO THE LOW/MID 40S FOR SE COASTAL LOCATIONS. IF ANY FROST
POTENTIAL EXISTS...IT WOULD LIKELY BE OVER THE PIEDMONT WHERE FULL
DECOUPLING COULD OCCUR.
THE HIGH DRIFTS OFFSHORE TUESDAY. LIGHT ONSHORE FLOW WILL MAINTAIN
RATHER COOL HIGHS IN THE LOW 60S (STILL NEAR -1.5 ST DEV) NEAR THE
COAST...AND LIGHT RETURN FLOW SHOULD ALLOW HIGHS TO RISE INTO THE
UPPER 60S TO NEAR 70 OVER THE PIEDMONT UNDER A MOSTLY SUNNY SKY.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
HI PRES WILL SLIDE INTO THE ATLC FOR TUE NGT THRU THU. A WARM
FRONT WILL SLOWLY LIFT THRU THE REGION AND OFFSHR LATE TUE NGT
THRU THU MORNG. AT THIS TIME...WILL MAINTAIN A DRY FCST DURING
THIS PERIOD...BUT ANY ISLTD PCPN WILL LIKELY OCCUR ACRS THE NRN
THIRD OF THE AREA. SLGT CHC FOR SHOWERS OR TSTMS...MAINLY ACRS THE
NRN HALF OF THE REGION THU AFTN INTO FRI MORNG...AS A WEAK TROF
MOVES THRU THE AREA. GOING WITH SLGT CHC FOR SHOWERS AND TSTMS
(OCCURRING MAINLY AFTN/EVENG HRS) FRI THRU SAT...IN RELATIVELY
WARM AND MARGINALLY UNSTABLE AIRMASS IN ADVANCE OF MAIN COLD FRONT
N OF THE REGION. MIN TEMPS WILL RANGE FM THE MID 40S TO LWR 50S
WED MORNG...AND MAINLY IN THE MID 50S TO LWR 60S THU...FRI...AND
SAT MORNGS. MAX TEMPS WILL RANGE THRU THE 70S WED...AND GENERALLY
IN THE UPR 70S TO MID 80S THU...FRI AND SAT.
&&
.AVIATION /20Z SATURDAY THROUGH THURSDAY/...
COLD FRNT CURRENTLY OVER WV WILL SLOWLY APPROACH THE MID ATLANTIC
THIS AFTERNOON. S/SW WINDS WILL OCCASIONALY GUST TO 20-25 MPH
THROUGH THE AFTN. SCATTER SHOWERS AND POSIBLE TSTMS ARE DEVELOPING
ACROSS THE AREA AHEAD OF THE COLD FRONT. TIMING OF THE
THUNDERSTORMS AT ANY GIVEN AIRPORT IS DIFFICULT AS THEY MOST
LIKELY WILL FORM IN VARIOUS GROUPS ON SMALL SCALE BOUNDARIES.
BELIEVE THE STRONGEST STORMS ARE LIKELY LATE THIS AFTERNOON AND
EVENING AND COULD SEE AN ISOLATED SEVERE STORM WITH BEST CHANCES
FOR IT TOWARD THE COAST. AFTER SUNSET WILL STILL SEE A NUMBER OF
SHOWERS AROUND BUT BELIEVE MOST OF THE THUNDER WILL END. COULD SEE
BRIED IFR CONDITIONS IN SOME OF THE EHAVIER THUNDERSTORMS THIS
AFTERNOON AND EVENING. OTHERWISE MAINLY VFR CONDTIONS. THESE SHOWERS WILL
END FROM WEST TO EAST AS THE COLD FRONT SLOWLY MOVES ACROSS THE
AREA. THE COLD FRONT MOVES OFF THE COAST DURING SUNDAY MORNING AND
SKIES WILL CLEAR WITH WINDS BECOMING NORTHWEST. VFR EXPECTED SUN
THRU THE MIDDLE OF NEXT WEEK WITH HI PRES IN PLACE.
&&
.MARINE...
NO HEADLINES IN THE SHRT TERM TNGT THRU MON. SSW WINDS 10 TO 20 KT
THIS EVENG...WILL BECOME W OR NW 10 TO 15 KT BY SUN MORNG AS THE
COLD FRONT MOVES TO JUST OFFSHR. NW OR N WINDS ARND 15 KT OR LESS
SUN MORNG INTO SUN AFTN...DUE TO MINOR SURGE BEHIND EXITING COLD
FRONT. ANOTHER NNW SURGE (SUB-SCA) EXPECTED SUN NGT INTO MON
MORNG...AS HI PRES BLDS TWD THE AREA FM THE W. THE HI WILL BLD
RIGHT OVR THE REGION LATE MON NGT THRU TUE...THEN SLIDES INTO THE
ATLC FOR TUE NGT INTO THU.
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...AJZ
NEAR TERM...AJZ
SHORT TERM...AJZ
LONG TERM...TMG
AVIATION...JAB
MARINE...TMG
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
416 PM EDT SAT MAY 11 2013
.SYNOPSIS...
A COLD FRONT CROSSES THE MID ATLANTIC TONIGHT FOLLOWED BY A
SECONDARY COLD FRONT SUNDAY EVENING. CANADIAN HIGH PRESSURE BUILDS
INTO THE REGION MONDAY AND MONDAY NIGHT BRINGING A VERY COOL
AIR FOR THE MIDDLE OF MAY...BEFORE SLIDING OFF THE COAST TUESDAY.
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
THE LATEST REGIONAL RADAR MOSAIC SHOWS ISOLATED TO SCATTERED SHOWERS
AND THUNDERSTORMS ACROSS THE REGION MARGINALLY UNSTABLE AIRMASS
(~1000 J/KG OF MLCAPE) ALONG WITH MODEST DEEP LAYER SHEAR (30-40KT
0-6KM). CURRENT GOES WATER VAPOR IMAGERY SHOWS A SHORTWAVE TROUGH
LIFTING NE ACROSS PA ALONG WITH STRONGER SYNOPTIC SCALE
DYNAMICS...HENCE ANY STORMS ACROSS THE LOCAL AREA HAVE STRUGGLED TO
ORGANIZE AND PERSIST. THIS TREND IS EXPECTED TO CONTINUE OVER THE
NEXT FEW HOURS BEFORE A JET STREAK OVER THE TENNESSEE VALLEY EJECTS
NE ACROSS THE REGION AHEAD OF A FRONTAL ZONE APPROACHING FROM THE
WEST.
THE LATEST RUC BRINGS THE JET ACROSS THE AREA DURING THE MID-EVENING
THROUGH EARLY OVERNIGHT HOURS. GIVEN THIS...A BAND OF LIKELY POPS
WILL BE FORECAST TO MOVE W-E OVER THE CWA. HOWEVER...QPF AMOUNTS
SHOULD BE RATHER MINIMAL. THUNDER WILL BE MAINTAINED THROUGH
MIDNIGHT TO ACCOUNT FOR ANY LINGERING INSTABILITY BEFORE
TRANSITIONING TO ONLY SHOWERS AFTER MIDNIGHT. LOW TEMPERATURES SHOULD
RANGE FROM THE LOW 50S NW...TO LOW 60S SE.
SHORT TERM...
STEADY CAA COMMENCES SUNDAY AS THE COLD FRONT MOVES OFF THE COAST
SUNDAY MORNING AND HIGH PRESSURE BUILDS OVER THE MISSISSIPPI VALLEY.
THIS SHOULD PRODUCE A RATHER PLEASANT DAY WITH LOW-LEVEL THICKNESS
VALUES SUPPORTING HIGHS IN THE UPPER 60S N/NW...TO THE LOW/MID 70S
SE UNDER AN INCREASINGLY SUNNY SKY.
&&
.SHORT TERM /6 AM SUNDAY MORNING THROUGH TUESDAY/...
STEADY CAA COMMENCES SUNDAY AS THE COLD FRONT MOVES OFF THE COAST
SUNDAY MORNING AND HIGH PRESSURE BUILDS OVER THE MISSISSIPPI VALLEY.
THIS SHOULD PRODUCE A RATHER PLEASANT DAY WITH LOW-LEVEL THICKNESS
VALUES SUPPORTING HIGHS IN THE UPPER 60S N/NW...TO THE LOW/MID 70S
SE UNDER AN INCREASINGLY SUNNY SKY.
A SECONDARY COLD FRONT SWINGS THROUGH THE REGION SUNDAY NIGHT. THE
CONTINUATION OF STEADY CAA OVERNIGHT WILL DRIVE LOW TEMPERATURES
DOWN INTO THE UPPER 30S N/NW TO THE MID/UPPER 40S FAR SE UNDER A
CLEAR SKY. THERE SHOULD BE ENOUGH MIXING ALONG WITH DRY AIR/LOW
DEWPOINTS TO INHIBIT ANY FROST DEVELOPMENT IN THE COLDER SPOTS.
VERY COLD AIR ALOFT FOR MID-MAY ARRIVES MONDAY DRIVING 1000-500MB
THICKNESS VALUES DOWN TO AROUND 532-540DAM. A STRONG VORT MAX/PV MIN
DIVES AROUND THE BACK-SIDE OF THE PARENT TROUGH DURING THE
AFTERNOON. THIS ENERGY DROPPING INTO THE TROUGH WILL DROP 500MB
HEIGHTS TO -2 TO -3 ST DEV PER 11/12Z GEFS MEAN AT 00Z TUESDAY.
GIVEN THIS...A BKN SC DECK IS EXPECTED TO DEVELOP DURING THE
AFTERNOON. LOW AND MID LEVEL LAPSE RATES WILL BE RATHER STEEP...SO
THERE WILL BE A MINIMAL POTENTIAL OF SHOWERS WHEN COMBINED WITH THE
COLD AIR ALOFT AND MID/UPPER LEVEL ENERGY. HOWEVER...POPS WILL BE
LIMITED BELOW 15 PERCENT AT THIS TIME GIVEN THAT THE AIRMASS WILL BE
VERY DRY (SFC DEWPOINTS IN THE MID/UPPER 20S INLAND).
850MB TEMPERATURES DROP TO AROUND 0C MONDAY...WHICH IS AROUND -2 ST
DEV BELOW NORMAL PER 11/12Z GEFS MEAN. FULLY MIXED...AS EXPECTED
WILL RESULT IN HIGH TEMPERATURES RANGING FROM THE UPPER 50S N...TO
NEAR 65 FAR S...WHICH WOULD ALSO BE AROUND -2 ST DEV BELOW SEASONAL
MEANS. DAYTIME HIGHS MAY BE REACHED AROUND MIDDAY BEFORE DROPPING A
FEW DEGREES IN THE AFTERNOON AS CLOUD COVER INCREASES.
CANADIAN HIGH PRESSURE SETTLES OVER THE PIEDMONT MONDAY NIGHT INTO
TUESDAY MORNING. THE SKY SHOULD CLEAR MONDAY EVENING...WHICH WILL
EVENTUALLY RESULT IN A COOL START TO THE DAY TUESDAY. FORECAST LOWS
RANGE FROM THE MID 30S OVER THE PIEDMONT AND E/S-CENTRAL VA COASTAL
PLAIN TO THE LOW/MID 40S FOR SE COASTAL LOCATIONS. IF ANY FROST
POTENTIAL EXISTS...IT WOULD LIKELY BE OVER THE PIEDMONT WHERE FULL
DECOUPLING COULD OCCUR.
THE HIGH DRIFTS OFFSHORE TUESDAY. LIGHT ONSHORE FLOW WILL MAINTAIN
RATHER COOL HIGHS IN THE LOW 60S (STILL NEAR -1.5 ST DEV) NEAR THE
COAST...AND LIGHT RETURN FLOW SHOULD ALLOW HIGHS TO RISE INTO THE
UPPER 60S TO NEAR 70 OVER THE PIEDMONT UNDER A MOSTLY SUNNY SKY.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
CANADIAN HIGH PRS SETTLES OVR THE AREA TUE RESULTING IN A COOL BUT
DRY BEGINNING TO THE PRD. COMBO OF DECOUPLING WNDS...CLR SKIES AND
RTHR LOW DP TMPS ALLOWS FOR GOOD RADITIONAL COOLING MON NITE. LOWS
FM THE U30S NW PIEDMONT TO M-U40S AT THE BEACHES. M SUNNY & COOL
TUE. HIGHS 65-70...XCPT U50S-L60S NRN BEACHES. LOWS TUE NITE 45-50.
LEANED TOWARD THE ECMWF FOR THE REST OF THE PRD. HIGH PRS MOVES S
OF RGN WED WITH A WRM FRNT APPRCHG FROM THE WEST. KEPT IT DRY FOR
NOW AS IT APPEARS ANY PCPN ASSCTD WITH THIS BNDRY STAYS N&W OF FA.
RETURN FLOW AND WRMG H85 TMPS RESULTS IN READINGS RISING INTO THE
M-U70S W OF CHES BAY...M60S-L70S AT THE BEACHES.
WILL CONT TO WATCH FOR ANY CONVECTIVE COMPLEXES THAT DVLP IN NW FLOW
ARND THE HIGH TO THE SOUTH. MODELS HINTING AT THIS OCCURRING WED
NITE INTO THU. GIVEN LOW CONFIDENCE THIS FAR OUT...ELECTED TO ONLY
GO WITH SLGHT CHC POPS ACROSS NRN HALF OF FA THU WHERE BEST SPRT WUD
BE. LOWS WED NITE IN THE M-U50S MUCH WRMR THU WITH HIGHS L-M80S WEST
OF CHES BAY...70S AT THE COAST.
LEE TROF DVLPMNT AHEAD OF NEXT FRNT SEEN FOR FRI...THUS WENT WITH A
SLGHT CHC POPS. HIGHS 80-85...XCPT 70S AT THE COAST.
&&
.AVIATION /20Z SATURDAY THROUGH THURSDAY/...
COLD FRNT CURRENTLY OVER WV WILL SLOWLY APPROACH THE MID ATLANTIC
THIS AFTERNOON. S/SW WINDS WILL OCCASIONALY GUST TO 20-25 MPH
THROUGH THE AFTN. SCATTER SHOWERS AND POSIBLE TSTMS ARE DEVELOPING
ACROSS THE AREA AHEAD OF THE COLD FRONT. TIMING OF THE
THUNDERSTORMS AT ANY GIVEN AIRPORT IS DIFFICULT AS THEY MOST
LIKELY WILL FORM IN VARIOUS GROUPS ON SMALL SCALE BOUNDARIES.
BELIEVE THE STRONGEST STORMS ARE LIKELY LATE THIS AFTERNOON AND
EVENING AND COULD SEE AN ISOLATED SEVERE STORM WITH BEST CHANCES
FOR IT TOWARD THE COAST. AFTER SUNSET WILL STILL SEE A NUMBER OF
SHOWERS AROUND BUT BELIEVE MOST OF THE THUNDER WILL END. COULD SEE
BRIED IFR CONDITIONS IN SOME OF THE EHAVIER THUNDERSTORMS THIS
AFTERNOON AND EVENING. OTHERWISE MAINLY VFR CONDTIONS. THESE SHOWERS WILL
END FROM WEST TO EAST AS THE COLD FRONT SLOWLY MOVES ACROSS THE
AREA. THE COLD FRONT MOVES OFF THE COAST DURING SUNDAY MORNING AND
SKIES WILL CLEAR WITH WINDS BECOMING NORTHWEST. VFR EXPECTED SUN
THRU THE MIDDLE OF NEXT WEEK WITH HI PRES IN PLACE.
&&
.MARINE...
SOUTHERLY FLOW CONTINUES TDY WITH HI PRES WELL OFFSHORE AND A COLD
FRNT APPROACHING FROM THE WEST. WILL MAINTAIN INHERITED SCA OVER THE
BAY WITH WINDS CURRENTLY GUSTING TO NEAR SCA CRITERIA...CONTINUING
AT TIMES THRU THE DAY AHEAD OF THE FRNT. SEAS HAVE BEEN SLOW TO BLD
HOWEVER 44009 HAS NOW MADE IT TO 4 FT AND EXPECT NORTHERN COASTAL
WATERS TO GET TO 5 FT LATER THIS MRNG THRU LATE AFTN. WILL HOLD OFF
ON ANY HEADLINES SOUTH OF PARRAMORE ISLAND WHERE 3-4 FT SEAS ARE
EXPECTED. WINDS WILL STAY SUB-SCA OVER THE RIVERS AND SOUND...WITH
THE LWR JAMES BEING CLOSE TO CRITERIA. THE COLD FRNT CROSSES THE
WATERS TNGT BUT WITH WEAKENING WINDS BEHIND THE FRNT WILL END THE
SCA AT 7 PM. SECONDARY SURGE MAY PRODUCE NW WINDS UP TO 15 KT SUN
AFTN. OTHERWISE...SUB-SCA CONDS FOR SUN THRU THE MIDDLE OF NEXT
WEEK AS SFC HI PRES BLDS INTO THE AREA.
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...AJZ
NEAR TERM...AJZ
SHORT TERM...AJZ
LONG TERM...MPR
AVIATION...MAS/JAB
MARINE...MAS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
449 PM EDT SAT MAY 11 2013
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 447 PM EDT SAT MAY 11 2013
WV IMAGERY AND RUC ANALYSIS INDICATED AN AMPLIFIED MID/UPPER LEVEL
PATTERN WITH A TROUGH FROM HUDSON BAY INTO THE WESTERN GREAT LAKES.
THE MID LEVEL LOW CENTER HAD DROPPED TO NEAR CYQT AS THE SHORTWAVE
TROUGH THAT SUPPORTED THE MORNING PCPN BAND SHIFTED INTO ERN UPPER
MI AND LAKE SUPERIOR. RADARS INDICATED THAT SCT -SHSN SUPPORTED BY
DIURNAL HEATING AND INFLUX OF COLDER AIR AND WRAP-AROUND MOISTURE
WERE SPREADING FROM NE MN AND WRN LAKE SUPERIOR INTO WRN UPPER MI.
UPSTREAM...THE 12Z CYPL SOUNDING INDICATED PLENTIFUL MOISTURE TO
INVERSION AROUND 12K FT(650)MB.
TONIGHT...MAINLY LIGHT SNOW SHOWERS ARE EXPECTED LATE THIS AFTERNOON
AND EVENING ACROSS THE WEST. HIGHER RES MODELS SUGGEST SHSN WILL
EXPAND IN COVERAGE AND INTENSITY ACROSS THE WEST FROM 00Z-03Z AND
INTO THE ERN CWA MAINLY AFT 03Z. WITH VERY FAVORABLE CONDITIONS FOR
LAKE ENHANCED SNOW DEVELOPING...SEVERAL INCHES OF SNOW WILL BE
POSSIBLE OVERNIGHT.
WITH CAA INCREASING AND WINDS VEERING AS A SECONDARY SHRTWV MOVES
THROUGH...TEMPS AT 850 MB FALL TO AROUND -8C WITH INVERSION TOP
TEMPS TO NEAR -18C...PER NAM. ALTHOUGH LAKE INDUCED CAPES ARE
RELATIVELY MODEST...MOISTURE THROUGH 650 MB AND SHARP CYCLONIC
LOW-LEVEL FLOW WILL BOOST CONVERGENCE AND ALLOW FOR AT A PERIOD OF
HEAVIER LAKE ENHANCED SNOW DOWNWIND OF LONGER FETCH OVER CNTRL AND
ERN LAKE SUPERIOR. SNOW ACCUMULATIONS IN THE 1 TO 4 INCH RANGE ARE
POSSIBLE WITH THE GREATEST AMOUNTS IN THE HIGHER TERRAIN FROM THE
HURON MOUNTAINS TO NEGAUNEE AND FROM ALGER COUNTY THROUGH NRN
SCHOOLCRAFT AND NRN LUCE COUNTY.
IN ADDITION TO THE SNOW...VERY STRONG WINDS ARE EXPECTED AFT 03Z AS
A PRES RISE MOVES THROUGH AND THE GRADIENT TIGHTENS WITH THE SFC LOW
DEEPENING E OF LAKE SUPERIOR. MIXED LAYER WINDS TO 40-45 KNOTS SUGGEST
POTENTIAL FOR WIND GUSTS TO AROUND 45 MPH IN EXPOSED LOCATIONS NEAR
THE LAKE SUPERIOR SHORELINE FROM MARQUETTE EASTWARD. A WINTER WEATHER
ADVISORY WAS ISSUED FOR THE COMBINATION OF WINDS AND SNOW.
SUN...WITH LINGERING DEEP CYCLONIC NNW FLOW AND AROUND -10C 8H
TEMPS MOVING ACROSS LAKE SUPERIOR IN THERMAL TROUGH...EXPECT SOME
LINGERING RAIN/SNOW SHOWERS EARLY IN THE MORNING OVER THE EAST WHERE
LONGER FETCH WILL BE MORE FAVORABLE FOR LAKE EFFECT EFFECT PCPN.
OTHERWISE...SHARP SUBSIDENCE/DRYING WITH A TRANSITION TO MORE NEUTRAL
OR ANTICYCLONIC FLOW FROM THE WEST BY AFTERNOON SHOULD BRING AND END
TO ANY LINGERING BY MID AFTERNOON. FAIRLY TIGHT NW PRES GRAD ON THE
BACKSIDE OF EXITING LOW WILL KEEP WINDS GUSTING TO NEAR 35 MPH OVER
THE ERN HALF COUNTIES ESPECIALLY NEAR LAKE SUPERIOR.
OTHERWISE...UNSEASONABLY COLD CONDITIONS WILL CONTINUE WITH HIGHS
RANGING FROM AROUND 40 NORTH AND EAST TO MID 40S SOUTH CENTRAL.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 447 PM EDT SAT MAY 11 2013
RELATIVELY COLD HIGH TEMPS ARE EXPECTED FOR SUN...SO GOING INTO SUN
NIGHT WITH SFC RIDGING AND ASSOCIATED CLEARING BUILDING IN FROM THE
W...SHOULD SEE SFC TEMPS FALL SHARPLY /ESPECIALLY OVER THE WRN
CWA/...EVEN THOUGH TEMPS ALOFT WARM SUN NIGHT. EXPECT LOWS SUN NIGHT
AROUND 20F /EVEN IN THE MID-UPPER TEENS IN COLDER SPOTS/ OVER
PORTIONS OF INTERIOR W UPPER MI...WITH LOWS AROUND OF BELOW FREEZING
IN MOST LOCATIONS. LOWERED TEMPS A FEW DEGREES IN COLDER SPOTS GIVEN
GUIDANCE COMING IN WITH COLDER TEMPS...BUT DID NOT GO AS LOW AS
COLDEST GUIDANCE.
SHOULD SEE 850MB TEMPS BETWEEN 18Z SUN AND 00Z TUE INCREASE BY 5C
OVER THE ERN CWA AND 12C OVER THE WRN CWA. THEREFORE...WILL SEE
WARMER TEMPS FOR MON THAN SUN...ESPECIALLY OVER THE WRN CWA. HIGH
TEMPS FOR MON ARE EXPECTED TO BE AROUND 60 OVER THE INTERIOR WRN CWA
AND AROUND 50 OVER THE FAR ERN CWA. COULD SEE SOME WAA PRECIP MOVING
ACROSS THE CWA LATE MON INTO MON NIGHT...BUT MOISTURE AND FORCING DO
NOT LOOK THAT IMPRESSIVE SO WILL KEEP POPS ON THE LOW END MON INTO
MON NIGHT.
MODELS HINT AT PRECIP FOR TUE ALONG A WARM FRONT AHEAD OF A
SHORTWAVE AND SFC LOW THAT MOVE INTO SRN MANITOBA BY 00Z WED.
AGAIN...MOISTURE AND FORCING WILL BE LIMITED SO WILL KEEP POPS LOW.
THUNDERSTORMS WILL BE POSSIBLE WITH THE PRECIP GIVEN ELEVATED
INSTABILITY AND DECENT LAPSE RATES. 850MB TEMPS INCREASE ANOTHER 13C
OVER THE WRN CWA TO 16C BETWEEN 00Z TUE AND 00Z WED...AND INCREASE
ANOTHER 10C TO 9C OVER THE FAR ERN CWA. SHOULD BE ABLE TO GET HIGHS
AROUND 70 OVER THE INTERIOR WRN CWA AND AROUND 60 OVER THE ERN CWA.
THE SFC LOW AND SHORTWAVE MOVE N OF THE CWA TUE NIGHT INTO
WED...WITH MODEL DISCREPANCIES ON TIMING OF THE SYSTEM. THIS BRINGS
A COLD FRONT ACROSS THE CWA BY AT LEAST 18Z WED /SLOWER GFS
TIMING/...WHICH WILL TURN WINDS OUT OF THE WNW AND COOL TEMPS A BIT.
SHOWERS AND THUNDERSTORMS WILL CONTINUE TO BE POSSIBLE. MOISTURE
WILL BE MORE LIMITED ALONG THE SRN CWA...SO WILL KEEP POPS LOWER
THERE. WILL GO WITH LIKELY POPS OVER THE NRN/ERN CWA WHERE MOISTURE
AND FORCING WILL BE BETTER. EVEN WITH COOLER OVERHEAD
AIRMASS...AFTER THE FRONT PASSES WED MORNING...SKIES WILL CLEAR
OUT...ALLOWING SFC TEMPS TO WARM UP HIGHER THAN THE CLOUDIER TUE
AWAY FROM LAKE SUPERIOR. HIGHS LOOK TO BE IN THE MID 70S OVER THE
SCENTRAL CWA WED...AND AROUND 70S ELSEWHERE OVER THE INTERIOR CWA.
THU THROUGH NEXT SAT...CONFIDENCE IS LOWERED BY LACK OF MODEL
AGREEMENT AND RUN TO RUN DISCONTINUITY. WILL JUST RUN WITH WHATEVER
CONSENSUS OF MODELS COMES UP WITH FOR THIS TIME PERIOD.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 447 PM EDT SAT MAY 11 2013
A PERIOD WITH CIGS JUST ABOVE MVFR THIS AFTERNOON IS EXPECTED TO
GIVE WAY TO MVFR CONDITIONS LATE THIS AFTERNOON AND EARLY EVENING AS
COLDER AIR MOVES INTO THE REGION ON NW WINDS. A PERIOD OF LAKE
ENHANCED SNOW AT CMX AND SAW LATE THIS EVENING AND OVERNIGHT SHOULD
DROP VSBY INTO THE IFR RANGE. GRADUAL IMPROVING CONDITIONS EXPECTED
AT ALL TAF SITES ON SUNDAY AS HIGH PRESSURE AND DRIER AIR ARRIVES.
INCREASING NORTHWEST WINDS WILL OCCUR AT ALL TAF SITES. STRONGEST
WINDS OVER 30 KTS ARE EXPECTED AT CMX LATE THIS AFTN THROUGH THE
EVENING...THEN AT SAW FROM LATE EVENING THROUGH THE REST OF THE
NIGHT.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 447 PM EDT SAT MAY 11 2013
EXPECT A STRONG GALE TO DEVELOP OVER MOST OF THE LAKE BY LATE THIS
EVENING AND LASTING INTO AT LEAST SUN MORNING BEFORE DIMINISHING. A
GALE WARNING REMAINS IN EFFECT FOR MUCH OF LK SUPERIOR FOR WINDS
40-45 KTS. RIDGING MOVES OVER LAKE SUPERIOR SUN NIGHT AND
MON...LEADING TO RELATIVELY CALM WINDS. WINDS WILL INCREASE OUT OF
THE S MON NIGHT THROUGH TUE NIGHT AHEAD OF A LOW PRESSURE SYSTEM
THAT WILL MOVE N OF LAKE SUPERIOR WED...BRINGING A SOUTHWEST SHIFT
TO THE WINDS WED.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER WEATHER ADVISORY FROM 11 PM THIS EVENING TO 8 AM EDT
SUNDAY FOR MIZ006-007-085.
WINTER WEATHER ADVISORY FROM 9 PM THIS EVENING TO 8 AM EDT
SUNDAY FOR MIZ005.
LAKE SUPERIOR...
GALE WARNING FROM MIDNIGHT TONIGHT TO 6 PM EDT SUNDAY FOR LSZ251-
267.
GALE WARNING FROM 10 PM THIS EVENING TO 6 PM EDT SUNDAY FOR
LSZ249-250-266.
GALE WARNING FROM 8 PM THIS EVENING TO 2 PM EDT SUNDAY FOR
LSZ243>245-264-265.
GALE WARNING FROM 10 PM THIS EVENING TO 8 AM EDT SUNDAY FOR
LSZ248.
GALE WARNING FROM 8 PM THIS EVENING TO 8 AM EDT SUNDAY FOR
LSZ263.
LAKE MICHIGAN...
GALE WARNING FROM MIDNIGHT TONIGHT TO 8 AM EDT SUNDAY FOR LMZ250.
&&
$$
SHORT TERM...JLB
LONG TERM...TITUS
AVIATION...JLB
MARINE...JLB
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1230 PM EDT SAT MAY 11 2013
LATEST UPDATE...
AVIATION
.SYNOPSIS...
ISSUED AT 334 AM EDT SAT MAY 11 2013
A COLD FRONT WILL MOVE THROUGH LOWER MICHIGAN TODAY BRINGING SHOWERS
WITH IT. COOLER WEATHER WILL FOLLOW FOR SUNDAY WITH WIDESPREAD FROST
EXPECTED SUNDAY NIGHT. A DRAMATIC WARM UP WILL DEVELOP EARLY NEXT
WEEK WITH HIGHS REACHING THE 80S MIDWEEK.
&&
.UPDATE...
ISSUED AT 1106 AM EDT SAT MAY 11 2013
NOTICED SOME LIGHTNING WITH THE CELL WEST OF LITTLE SABLE POINT.
BASED ON THIS I ADDED THUNDER TO THE FORECAST FOR SOUTHWEST MI
THIS AFTERNOON. THIS FRONT WILL MOVE QUICKLY THROUGH THE REGION
THIS AFTERNOON. BY 22Z IT SHOULD BE EAST OF LANSING. POPS WERE
ADJUSTED SLIGHTLY BECAUSE OF THE FASTER FRONTAL MOVEMENT.
&&
.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 334 AM EDT SAT MAY 11 2013
FORECAST CONCERNS DEAL WITH PCPN TRENDS TODAY AND FROST/FREEZE
CHANCES TONIGHT AND SUNDAY NIGHT.
LOW PRESSURE OVER WISCONSIN WILL DRAG A COLD FRONT ACROSS THE CWA
THIS AFTERNOON. REGIONAL RADAR SHOWS A BROKEN LINE OF SHOWERS MOVING
ACROSS THE UPPER MIDWEST. LOOK FOR THIS TO FILL IN A BIT BETTER THIS
AFTERNOON. WE DON/T EXPECTED TO MUCH RAIN WITH THIS AS MOISTURE IS
SOMEWHAT LIMITED. CAN/T RULE OUT THUNDER AS MUCAPES ARE IN THE
150-200 J/KG RANGE BUT OVERALL INSTABILITY IS ON THE LOW SIDE.
COLDER AIR WILL FLOW INTO THE CWA TONIGHT AND FROST IS POSSIBLE OVER
THE NRN 2 TIERS OF COUNTIES. COLD ADVECTION WILL CONTINUE SUNDAY AS
H8 TEMPS FALL TO -8C WHICH WILL YIELD LAKE DELTA T/S AROUND 13C.
SHOULD SEE SOME LAKE CLOUDS WITH THIS SETUP ALONG WITH A CHANCE OF
SHOWERS...SOME OF WHICH MAY BE MIXED WITH SNOW OVER THE NRN CWA.
AS THE UPPER TROUGH MOVES AWAY SUNDAY NIGHT SKIES SHOULD CLEAR AND
TEMPS WILL FALL INTO THE 20S/LWR 30S. WIDESPREAD FROST IS EXPECTED
WITH FREEZING TEMPS OVER MUCH OF THE CWA. A FREEZE WARNING MAY BE
NEEDED SUNDAY NIGHT.
.LONG TERM...(MONDAY NIGHT THROUGH FRIDAY)
ISSUED AT 334 AM EDT SAT MAY 11 2013
TYPICAL OF SPRING IN MICHIGAN OUR WARM THEN COLD THEN WARM AGAIN
WEATHER PATTERN WILL CONTINUE. MY ISSUE TODAY IS MOSTLY FOCUSED ON
WHAT HAPPENS TO THE FRONT THAT MOVES INTO THE AREA WEDNESDAY... DOES
IT STALL NEAR SOUTHWEST MICHIGAN PUTTING US BACK INTO A RAINY
PATTERN OR DOES IT SLIP FAR ENOUGH SOUTH TO DRY US OUT LATE THIS
COMING WEEK?
THE LARGE SCALE PATTERN CONTINUES TO FEATURE A HIGH AMPLITUDE UPPER
AIR PATTERN WITH CONSIDERABLE MERIDIONAL FLOW (WHY IT IS GETTING SO
COLD THIS WEEKEND). ALL OF THE OPERATIONAL MEDIUM RANGE MODELS
CONTINUE TO SUGGEST THIS PATTERN WILL FLATTEN OUT EARLY THIS COMING
WEEK. WE END UP WITH ONE OF THOSE EXTENDED EAST ASIAN JET FEATURES
BY MIDWEEK. TYPICALLY FOR SOUTHWEST MICHIGAN THAT MEANS WARMER THAN
NORMAL TEMPERATURES AND FREQUENT SHORTWAVES PRODUCING FREQUENT
PERIODS OF PRECIPITATION. ALL OF THIS HAS BEEN AND CONTINUES TO BE
THE MAIN ASPECT OF THE CHANGING UPPER AIR PATTERN. SO THE QUESTION
BECOMES... DOES THE FLATTER FLOW FORECAST BY THE ECMWF FROM
WEDNESDAY ON BECOME THE TRUE PATTERN OR WILL THE MORE AMPLIFIED
PATTERN OF THE GFS PREVAIL (THAT WOULD BE DRIER AND COOLER FOR
SOUTHWEST MICHIGAN)?
THERE ARE TWO CONCERNS OF MINE AS TOO WHY I QUESTION THE ECMWF THIS
TIME. FIRST IS THE SYSTEM MOVING ONTO THE WEST COAST CURRENTLY IS A
VERY DEEP TROUGH WITH A STRONG PACIFIC SYSTEM MOVING THROUGH THE
BASE OF THE TROUGH (JUST OFF THE OR/WA COAST). THE ECMWF FLATTENS
THIS WAVE AMAZINGLY FAST GIVEN ITS CURRENT AMPLITUDE. ALSO BOTH THE
ECMWF AND GFS SHOW A CLOSE UPPER HIGH DEVELOPING BY TUESDAY JUST
SOUTH OF GREENLAND. THAT THEN PERSISTS ON BOTH MODELS THROUGH THE
REST OF THE WEEK. OUR UPPER AIR FLOW WILL BE BLOCKED TO OUR EAST.
GIVEN THE BLOCKING TO THE EAST AND STRENGTH OF THE PACIFIC SYSTEM
MOVING ON SHORE (OUR WEDNESDAY SYSTEM) I WOULD HAVE TO FAVOR THE GFS
AT THIS POINT(MORE AMPLIFIED UPPER AIR PATTERN).
THE MORE AMPLIFIED PATTERN WOULD SUPPORT A STRONG COLD FRONT
WEDNESDAY EVENING WITH STRONGER THUNDERSTORMS BUT IT WOULD ALSO MEAN
A WARMER WEDNESDAY... THICKNESS VALUES AND 850 AND 925 MB TEMPS ARE
FORECAST TO BE AS WARM ENOUGH FOR LOWER TO MID 80S WEDNESDAY. SO I
HAVE TO IMAGINE EVEN WITH SOME FRONTAL CLOUDS AROUND MOST INLAND
AREAS SHOULD SEE HIGHS INTO THE LOWER 80S WEDNESDAY. WITH THAT MORE
AMPLIFIED PATTERN THE FRONT WOULD GO SOUTH OF MICHIGAN THURSDAY AND
IT WOULD COOL OFF SOME FOR THE REST OF THE WEEK.
IF THE ECMWF IS CORRECT... THE UPPER LOW OVER THE SW CONUS GETS
BOOTED EAST NORTHEAST TOWARD THE GREAT LAKES AND THAT BRING US A
STALLED FRONT WITH PERIODS OF SHOWERS AND THUNDERSTORMS WEDNESDAY
THROUGH FRIDAY (AND BEYOND).
FOR NOW I WILL SLIGHTLY FAVOR THE GFS AND KEEP POPS LOW WED THROUGH
FRIDAY. WE SHALL SEE HOW THIS PLAYS OUT.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY)
ISSUED AT 1230 PM EDT SAT MAY 11 2013
A COLD FRONT WILL BRING SCATTERED SHOWERS THROUGH MID AFTERNOON.
WINDS FROM MID TO LATE AFTERNOON WILL GUST TO 25 TO 30 KTS OUT OF
THE WNW BEFORE DECREASING TONIGHT. PRIMARILY IFR/MVFR CONDITIONS
THIS AFTERNOON WILL IMPROVE TO VFR LATE THIS AFTERNOON AND TONIGHT.
VFR CONDITIONS SHOULD THEN CONTINUE THRU 18Z SUN AND WNW WINDS WILL
INCREASE TO 15 TO 20 KTS WITH GUSTS TO AROUND 25 KTS BEGINNING MID
MORNING SUNDAY.
&&
.MARINE...
ISSUED AT 1106 AM EDT SAT MAY 11 2013
STRONGER GUSTS TO GALE FORCE ASSOCIATED WITH THE COLD FRONT ARE
SHOWN ON THE HRRR RUC. FSL RUC HAD GUSTS OVER 30 KNOTS. STABILITY
OF THE LAKE MAY BE AN ISSUE...LIMITING THIS RISK. SO FAR THE HRRR
IS VERIFIY WELL WITH THE UPSTREAM GUSTS. WENT AHEAD AND ISSUED A
GALE WARNING. THE WINDS WILL BE SHIFTING SHARPLY...ADDING TO THE
HAZARD. BY 00Z A LULL IN THE WINDS IS FORECASTED...SO THE GALE
WARNING IS OF A SHORTER DURATION. MAY NEED TO EXTEND IT AS THE
WINDS WILL PICK BACK UP BY DAYBREAK SUNDAY.
&&
.FIRE WEATHER...
ISSUED AT 334 AM EDT SAT MAY 11 2013
SHOWERS ARE EXPECTED MAINLY THIS AFTERNOON. COOLER TEMPERATURES WILL
FOLLOW SUNDAY WITH HIGHS IN THE 40S.
&&
.HYDROLOGY...
ISSUED AT 334 AM EDT SAT MAY 11 2013
RAINFALL LESS THAN A QUARTER INCH TODAY WILL HAVE A NEGLIGIBLE
EFFECT ON RIVERS.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...GALE WARNING UNTIL 8 PM EDT THIS EVENING FOR LMZ844>849.
&&
$$
UPDATE...MJS
SYNOPSIS...93
SHORT TERM...93
LONG TERM...WDM
AVIATION...LAURENS
FIRE WEATHER...93
HYDROLOGY...93
MARINE...MJS
AREA FORECAST DISCUSSION
NWS RALEIGH NC
150 PM EDT SAT MAY 11 2013
.SYNOPSIS...
A COLD FRONT MOVES SLOWLY THROUGH THE REGION OVERNIGHT. COOL HIGH
PRESSURE THEN BUILDS INTO THE REGION ON SUNDAY AND PERSISTS THROUGH
TUESDAY. BY WEDNESDAY...AS THE HIGH MOVES EAST...A WARMER SOUTHERLY
FLOW RETURNS.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1025 AM SATURDAY...
MORNING PROXIMITY SOUNDINGS...MSAS...AND SPC MESOANALYSIS SHOWING
CURRENTLY THE GREATEST INSTABILITY FROM THE COASTAL PLAIN EASTWARD
WHERE THE DEEPEST MOISTURE RESIDES IN AND NEAR CENTRAL NORTH
CAROLINA. THERE ARE A FEW POSITIVE FACTORS FOR DEEP CONVECTIVE
DEVELOPMENT DURING THE AFTERNOON...INCLUDING WEAK SHORTWAVES MOVING
INTO THE AREA ON THE SOUTHWEST FLOW ALOFT...VERY MODEST COOLING
ALOFT ABOUT A DEGREE OR MAYBE TWO CELSIUS AS NOTED ON THE 12Z
UPPER-AIR ANALYSES...THE APPROACH OF A SURFACE TROUGH...AND THE
DIGGING UPPER TROUGH ON WATER VAPOR TO OUR NORTHWEST. 0-6KM SHEAR
INCREASES AS WELL...THOUGH MODEL SOUNDINGS NOTE THE INSTABILITY
SHOULD BE SOMEWHAT LIMITED WITH MIXED-LAYER CAPE FROM ABOUT 500 TO
1000J/KG. THE MID- AND UPPER-LEVEL JETS SHOULD BE LOCATED TO OUR
NORTHWEST THIS AFTERNOON AND LIKELY NOT COINCIDE WITH THE PERIOD OF
GREATEST HEATING...AND THE STRONGEST LOW-LEVEL WINDS SHOULD BE ALONG
AND OFF THE COAST. THE RUC AND THE NAM DIFFER ON THE LOCATION OF THE
GREATER MOISTURE AND INSTABILITY LATER THIS AFTERNOON...AS THE NAM
SHARPENS THE SURFACE TROUGH FARTHER EAST AND HAS A MORE PROGRESSIVE
PATTERN TO ADVANCING SHOWERS AND THUNDERSTORMS...WHILE THE RUC IS
SLOWER AND FARTHER WEST. HODOGRAPHS ARE FAIRLY STRAIGHT-LINE LATE
THIS AFTERNOON. OVERALL...THINK THE POTENTIAL FOR DEEP CONVECTION IS
GOOD AND HAVE MAINTAINED THE ORIENTATION OF CHANCES FOR SHOWERS AND
THUNDERSTORMS INCREASING TO LIKELY THIS AFTERNOON TOWARD THE TRIAD
AND ELSEWHERE ACROSS THE NORTHWEST PIEDMONT...SPREADING EAST AND
SOUTHEAST LATE THIS AFTERNOON INTO THE EVENING WITH AN ADVANCING
TROUGH AND COOL POOL PROCESSES FROM SMALL BANDS OF STORMS.
GIVEN THE HEATING OF THE DAY...INSTABILITY COULD BE A LITTLE GREATER
THAN FORECAST...ALTHOUGH LIMITED COOLING ALOFT SHOULD PRECLUDE
REALLY HIGH INSTABILITY. INCREASING SHEAR SHOULD HELP OVERCOME SOME
GENERALLY SLENDER CAPE ON THE LATEST BUFR SOUNDINGS AND MODEST WIND
FIELDS. SHOULD STORMS BECOME SEVERE...THE MAIN THREAT SHOULD BE
DOWNBURST WINDS...WITH A LESSER POTENTIAL FOR LARGE HAIL. NOT
ANTICIPATING A WIDESPREAD SEVERE WEATHER EVENT CURRENTLY...MORE
ISOLATED. THE BEST TIMING STILL APPEARS TO BE 2 OR 3 PM TO 9 PM.
INCREASED TEMPERATURES IN MOST AREAS A DEGREE OR TWO BASED ON THE
AMOUNT OF SUN AVAILABLE OVER CENTRAL NORTH CAROLINA AS OF THIS
WRITING...MORE IN LINE WITH MAV MOS AND BIAS-CORRECTED MOS GUIDANCE
GRIDDED DATA...AS WELL AS 1000-850MB THICKNESSES FORECAST BY THE
GFS. WITH THE INCREASE IN HEATING SHOULD BE REALIZED A FEW MORE WIND
GUSTS IN THE 20 TO 25 MPH RANGE AT TIMES. DRY COOL AIR ADVECTION
WILL REACH WESTERN PORTIONS OF THE FORECAST AREA BY DAYBREAK
SUNDAY...DROPPING TEMPERATURES INTO THE MID 50S WEST WHILE HOLDING
IN THE LOWER 60S EAST.
&&
.SHORT TERM /SUNDAY AND SUNDAY NIGHT/...
AS OF 300 AM SATURDAY...
SHOWERS WILL BE IN THE PROCESS OF EXITING OFF THE COAST BY DAYBREAK
SUNDAY WITH INITIAL SURGE OF DRY AND COOLER AIR RESULTING IN NW TO
SE CLEARING SUNDAY MORNING. MEANWHILE...SLOW EASTWARD PROGRESSION OF
AMPLIFYING MID/UPPER LEVEL TROUGH WILL DELIVER A SECONDARY SURGE OF
DRY COOL AIR LATE IN THE DAY AS A MODIFIED CP AIRMASS BUILDS
SOUTHWARD REACHING THE GULF COAST AND SOUTHEAST US
SUNDAY NIGHT/MONDAY MORNING. HIGHS SUNDAY IN THE L-70S WEST TO
MID/UPPER 70S SOUTHEAST. CHILLY OVERNIGHT LOWS IN THE LOWER 40S TO
AROUND 50.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
AS OF 245 AM SATURDAY...
SURFACE HIGH PRESSURE WILL BUILD OVER THE REGION THROUGH EARLY NEXT
WEEK. THE MID/UPPER LEVEL TROUGH WILL STILL BE OVER THE AREA ON
MONDAY...BEFORE FINALLY MOVING EAST OF THE AREA MONDAY NIGHT.
THEREFORE...TEMPS ON MONDAY WILL BE WELL BELOW NORMAL...WITH HIGH
GENERALLY ONLY REACHING INTO THE MID/UPPER 60S TO POSSIBLY NEAR 70
DEGREES ACROSS THE FAR SOUTH. WITH THE SURFACE HIGH OVERHEAD MONDAY
NIGHT...GOOD RADIATIONAL COOLING CONDITIONS WILL SET UP...ALLOWING
OVERNIGHT LOWS TO FALL INTO THE LOW/MID 40S...WITH EVEN SOME UPPER
30S POSSIBLE IN THE USUALLY COOLER LOCALES.
THE SURFACE HIGH WILL SHIFT OFFSHORE LATE TUESDAY INTO WEDNESDAY AND
HEIGHTS WILL BEGIN TO RISE AS SHORTWAVE RIDGING BUILDS EAST OVER THE
AREA. THIS WILL ALLOW TEMPS TO MODERATE...ALTHOUGH ANOTHER DAY OF
BELOW NORMAL TEMPS IS EXPECTED ON TUESDAY (BUT SLIGHTLY WARMER THAN
MONDAY). BY WEDNESDAY...TEMPS SHOULD RETURN TO NEAR NORMAL...WITH
ABOVE NORMAL TEMPS EXPECTED BY THE END OF THE WEEK. THERE
CONTINUES TO BE DISAGREEMENT WITH RESPECT TO THE TIMING OF OUR NEXT
SYSTEM/BREAKDOWN OF THE MID LEVEL RIDGE. NEVERTHELESS...WILL SHOW
SLIGHT CHANCE DIURNAL POPS FOR FRIDAY AS SOUTHWESTERLY FLOW
INCREASES AND MODELS ARE HINTING AT A LEE TROUGH SETTING UP (HOWEVER
THE GFS BRINGS OUR NEXT FRONT IN ON FRIDAY...WHICH WOULD MEAN HIGHER
POP CHANCES...BUT THIS HAS BEEN CHANGING DAILY SO CONFIDENCE IS
LOW).
&&
.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
AS OF 150 PM SATURDAY...
OUTSIDE OF ANY SHOWERS AND THUNDERSTORMS...VFR CONDITIONS WILL
PREVAIL OVER CENTRAL NORTH CAROLINA. CONDITIONS COULD BECOME MVFR
FOR A TIME OVER THE NORTHWEST PIEDMONT VERY LATE THIS AFTERNOON AND
INTO THIS EVENING IN ANY AREA OF MORE STRATOFORM SHOWERS...BEHIND
ANY BANDS OF STRONGER SHOWERS OR STORMS. SKIES WILL GRADUALLY CLEAR
LATE TONIGHT AND INTO EARLY SUNDAY AS WINDS VEER WITH THE PASSAGE OF
A COLD FRONT. THE FRONT SHOULD BE A SLOW MOVER...AND ONLY EXIT
CENTRAL NORTH CAROLINA EAST OF THE INTERSTATE 95 CORRIDOR JUST
BEFORE SUNRISE. UNTIL THE ACTUAL FRONT PASSES...THERE APPEARS TO BE
ENOUGH MOISTURE AND LIFT FOR AVIATION INTERESTS TO BE AWARE OF THE
POTENTIAL FOR ISOLATED-TO-SCATTERED...LINGERING SHOWERS. DURING
SUNDAY MORNING...WITH MIXING...ANTICIPATE A FEW GUSTS DEVELOPING
INTO THE TEENS KNOTS FROM THE NORTHWEST.
BEYOND THE 18Z VALID TAF PERIOD...THERE IS A HIGH PROBABILITY OF VFR
CONDITIONS SUNDAY THROUGH TUESDAY. AS HIGH PRESSURE MOVES OFF TO THE
EAST AND A SOUTHERLY FLOW DEVELOPS OVER CENTRAL NORTH CAROLINA...THE
POTENTIAL FOR EARLY MORNING LOW CLOUDS INCREASES A LITTLE...
PARTICULARLY TOWARD KGSO WEDNESDAY. BASED ON CURRENT MODEL SOUNDINGS
FROM THE GFS...THERE IS A HIGHER POTENTIAL FOR SUB-VFR CONDITIONS
MAINLY IN LOW CLOUDS LATE WEDNESDAY NIGHT INTO THURSDAY MORNING.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...DJF
NEAR TERM...CBL/DJF
SHORT TERM...CBL
LONG TERM...KRR
AVIATION...DJF
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
125 PM EDT SAT MAY 11 2013
.SYNOPSIS...
CONVECTION WILL AFFECT THE AREA LATER TODAY AS A COLD FRONT
APPROACHES FROM THE WEST. THE FRONT WILL MOVE ACROSS THE FORECAST
AREA AND OFFSHORE DURING SUNDAY. COOLER AND DRIER CONDITIONS WILL
AFFECT THE FORECAST AREA MONDAY THROUGH WEDNESDAY AS COOL
CANADIAN HIGH PRESSURE TRACKS ACROSS THE REGION RESULTING WITH
TEMPERATURES RUNNING 5 TO 10 DEGREES BELOW NORMAL. A WARMING TREND
IS EXPECTED AT THE END OF THE WEEK ONCE THE HIGH MOVES OFFSHORE
FROM THE CAROLINA COASTS.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 120 PM SATURDAY...CAPE FEAR SEABREEZE CONVECTION ALREADY COME
AND GONE. THE REST OF THE FORECAST REMAINS RATHER PROBLEMATIC. SAT
IMAGERY CLEARLY SHOWS SUBSIDENCE ACRS MUCH OF THE REGION WITH EVEN
CU FIELDS FAILING TO DEVELOP DESPITE SURFACE TEMPS THAT WOULD
OTHERWISE BE SUPPORTIVE OF SUCH. THE CONVECTIVE DEBRIS STREAMING
ACROSS THE REGION MAKES IT DIFFICULT TO DISCERN THE LOCATION OF ANY
MEANINGFUL MID LEVEL POCKETS OF ENERGY. THAT SAID THE WRF NOW SHOWS
A PRONOUNCED VORT MIN (SUBSIDENCE) MOVING OVER THE REGION FROM THE
SOUTHWEST AT THIS TIME. ASSUMING THIS MODEL IS BETTER INITIALIZED
THEN THE NEXT FEW HOURS MAY BE RATHER QUIET. THE EXIT OF THE VORT
MIN FUNCTIONALLY THE SAME AS THE APPROACH OF A MAX SO ASCENT IN THE
MID LEVELS MAY BE REALIZED LATE AFTERNOON AND AN ATYPICALLY LATE
START TO STORM INITIATION STILL SEEMS POSSIBLE. FORECAST HAS NOT
CHANGED MUCH THE SENSE OF TIMING HAS JUST BEEN DELAYED A LITTLE.
AS OF 1030 AM SATURDAY...NOT THE MOST STRAIGHTFORWARD FORECAST IN
THE WORLD AT THIS POINT. SAT IMAGERY THIS MORNING SHOWS AMPLE BREAKS
IN THE CLOUDS AND MODERATE TO STRONG HEATING SHOULD GET UNDERWAY
TODAY. INSTABILITY NOT SO MUCH IN QUESTION WITH RESPECT TO
THUNDERSTORMS AS MUCH AS FORCING MECHANISM. CU FIELDS ALREADY
DEVELOPED OVER CAPE FEAR REGION AND HRRR SUGGESTS THAT ISO
CONVECTION MAY POP UP IN THIS VC BTW NOW AND 18Z...WHICH SEEMS
PLAUSIBLE ENOUGH. THERE SHOULD THEN BE A BREAK FOR A FEW HOURS AT
WHICH TIME ATTENTION TURNS TO OUR WEST. LATE AFTERNOON/EARLY EVENING
CONVECTION TO DEVELOP AND MOVE INTO THE REGION. LATEST SWODY1 FROM
SPC REDUCED SLIGHT RISK AREA CONSIDERABLY TAKING THE ENTIRE AREA
OUT. GIVEN THAT INSTABILITY LIKELY CAPPED AT 1000J PER KG AND SHEAR
MINIMAL THIS SEEMS FINE. WILL LEAVE FCST WORDING AS-IS WITH THE POSS
OF STRONG (SM HAIL AND GUSTY WINDS) BUT NOT SEVERE WORDING. LINE OF
STORMS MOVING IN FROM THE WEST LARGELY MISS SC COUNTIES ESP FURTHER
EAST INC GRAND STRAND AND MAY JUST MISS CAPE FEAR REGION TO THE N
AND W ALSO.
AS OF 630 AM SATURDAY...THE EVOLVING AND AMPLIFYING FULL LATITUDE
UPPER TROF OCCUPYING THE CENTRAL U.S. TODAY...AND THE EASTERN
THIRD OF THE U.S. BY DAYBREAK SUNDAY...WILL BE THE MAIN PLAYER
UPSTAIRS DURING THIS NEAR TERM PERIOD. FORTUNATELY THE SOUTHERN
STREAM CUT-OFF LOW OVER THE SW U.S. DOES NOT GET ABSORBED WITHIN
THE FLOW DURING THE EVOLUTION OF THIS UPPER TROF. WILL HAVE TO
CONTEND WITH ROTATING MID LEVEL VORTICIES/IMPULSES TRACKING ALONG
THE EAST SIDE OF THIS UPPER TROF AXIS. MODELS INDICATE THE
POSSIBILITY OF 1 TRACKING ACROSS THE CENTRAL CAROLINAS THIS
AFTERNOON AND EVENING...AIDING UPWARD FORCING IE. UVVS. DURING
THIS TIME PERIOD...A LEE SIDE...PRE-FRONTAL TROF...WILL HAVE
DEVELOPED ACROSS THE CENTRAL CAROLINAS AND SLOWLY TRACK TOWARDS
THE COAST THIS AFTERNOON AND EVENING. THE TIMING OF THIS UPPER
FEATURE AND ITS INTERACTION WITH THE SFC TROF COULD BE THE
DIFFERENCE FOR STRONG TO POSSIBLY SEVERE THUNDERSTORM ACTIVITY.
MODEL TIMING DIFFERENCES CONTINUE WITH THIS POSSIBLE INCREASED
POTENTIAL...IF IT OCCURS AT ALL. AT THIS POINT...WILL HIGHLIGHT
THE ISOLATED SEVERE IN THE HWO BUT MAINLY FOR THE INLAND COUNTIES.
SPC INDICATES LARGE HAIL AND DAMAGING WIND GUSTS THE PRIMARY
SEVERE THREATS. THE SFC BASED STABLE MARINE LAYER WILL BE CONFINED
BASICALLY TO THE COAST DUE TO THE STRONG SW-W WINDS JUST OFF THE
DECK PREVENTING ANY INLAND PROGRESSION OF THE SEA BREEZE.
SREF PROBS OF MEASURED PCPN CONTINUES THE GENERAL TREND FROM
YESTERDAY HIGHLIGHTING SPLIT PCPN MAXIMAS ASSOCIATED WITH THIS
CONVECTION. MEANING...THE ILM CWA REMAINS IN THE MIDDLE OR WITHIN
THE LOWEST PROBABILITY FOR MEASURED PCPN...IE. DRIER. WITH ALL THIS
SAID...HAVE SLIGHTLY LOWERED POPS TO 40 TO 60 PERCENT DURING THE
PEAK OF THIS AFTERNOON/EARLY EVENING CONVECTION. NAM AND GFS MOS
GUIDANCE REMAIN SIMILAR TO MAXES TODAY WITH MID 80S INLAND...UPPER
70S ALONG THE IMMEDIATE COAST PRIOR TO THE PINNED SEA BREEZE
DEVELOPMENT. HAVE STAYED CLOSER TO THE HIER SIDE OF MODEL MOS
GUIDANCE FOR TONIGHTS LOWS...DUE TO A SLOWER PROGRESSION OF THE
CFP ACROSS THE FA.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 3 AM SATURDAY...THE COLD FRONT WILL BE JUST INLAND AT THE
BEGINNING OF THE PERIOD AND WILL QUICKLY MOVE OFFSHORE DURING THE
MORNING HOURS. MAINTAINED THE INHERITED POPS WHICH SHOW GOOD
CHANCE ALONG THE COAST WITH MINIMUM VALUES INLAND. BY SUNDAY
AFTERNOON THE FRONT IS WELL OFFSHORE AND HAVE REMOVED POPS FROM
THE 0000-0600 UTC TIME FRAME. A TEMPERATURE FORECAST FROM THIS
POINT ON AS A SECONDARY SHORTWAVE THAT MOVES ACROSS MONDAY
AFTERNOON BRINGS ALONG THE BEST COLD AIR ADVECTION. THE MID
AFTERNOON ARRIVAL OF THE COLD AIR WILL ALLOW TEMPERATURES TO RISE
AT OR JUST ABOVE 70 MONDAY. TUESDAY MORNING LOWS REMAIN IN THE 40S
MODERATED BY A FEW KNOTS OF WIND REMAINING IN THE BOUNDARY LAYER.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
AS OF 3 AM SATURDAY...THE MID LEVEL PATTERN WILL QUICKLY CHANGE
FROM EAST COAST TROUGHING TO A QUASI ZONAL FLOW AS WEAK
SHORTWAVES WILL MOVE QUICKLY ACROSS THE CONUS. WPC GRAPHICS ARE
DOMINATED BY A PREFERENCE FOR THE ECMWF ENSEMBLE MEAN. ALL IS
QUIET UNTIL FRIDAY REGARDING POPS WHEN A WEAK SHORTWAVE WILL ALLOW
A PIEDMONT TROUGH TO DEVELOP AND MAINTAINED THE SLIGHT CHANCE
POPS. FORCING IS NEGLIGIBLE AS WOULD BE EXPECTED WITH THE LACK OF
MID LEVEL AMPLITUDE AND THIS SEEMS REASONABLE. TEMPERATURE TRENDS
REMAIN IN PLACE WITH A QUICK RECOVERY FROM BELOW NORMAL VALUES
EARLY TO SLIGHTLY ABOVE NUMBERS LATE.
&&
.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
AS OF 18Z...LOOKS LIKE SOME SEA BREEZE ACTIVITY WILL OCCUR FOR THE
FIRST COUPLE OF HOURS OF TAF TIME...MAINLY OVER NORTH CAROLINA.
THEIR LOCATION AND MOTION WILL KEEP THEM AWAY FROM ILM. THUNDER WILL
ISOLATED. THIS EVENING...A COLD FRONT APPROACHES FROM THE
WEST...WITH SCATTERED TO POSSIBLY NUMEROUS CONVECTION OUT AHEAD.
WENT WITH INTERMITTENT THUNDER AT THE INLAND TERMINALS...BUT THIS
MAY BE OVERDONE. CONVECTION REACHES THE COAST 2-3 HOURS LATER. THE
CONVECTION WILL LIKELY BE WANING FOR DIURNAL REASONS. LOOK FOR A
WIND SHIFT TO THE WEST...THEN NORTHWEST AS THE COLD FRONT PUSHES
THROUGH. CONDITIONS WILL IMPROVE TO VFR FIRST AT THE INLAND
TERMINALS...WITH MVFR/IFR CEILINGS HOLDING ON NEAR THE COAST THROUGH
DAYBREAK...BECOMING VFR WITH A NORTHWEST WIND BY MID MORNING.
EXTENDED OUTLOOK...VFR CONDITIONS SUNDAY AFTERNOON THRU WEDNESDAY
DUE TO COOL CANADIAN HIGH PRESSURE. MORNING FOG POSSIBLE THURSDAY.
&&
.MARINE...
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1030 AM SATURDAY...LITTLE TO NO CHANGES IN FORECAST THINKING
AT THIS TIME. SW GRADIENT WINDS TO INC SLIGHTLY POSSIBLY BOOSTING
SEAS HIGH ENOUGH TO WARRANT SCEC OVER NRN ZONE OR TWO.
AS OF 630 AM SATURDAY...A PRE-FRONTAL TROF WILL DEVELOP ACROSS THE
EAST CENTRAL CAROLINAS TODAY...AND MESH WITH THE APPROACHING COLD
FRONT TONIGHT. THIS FRONT WILL JUST REACH THE CAROLINA COASTS
AROUND DAYBREAK SUNDAY. THE SFC PRESSURE PATTERN AND TIGHTENING
GRADIENT AHEAD OF THE INLAND TROF WILL PRODUCE A SOLID SSW-SW WIND
AT 15 TO 20 KT...WITH A FEW GUSTS UP TO 25 KT POSSIBLE ACROSS THE
ILM NC WATERS. SIGNIFICANT SEAS WILL PRIMARILY BE A FUNCTION OF
THE 4 TO 6 SECOND PERIOD LOCALLY PRODUCED WIND DRIVEN WAVES.
THEREFORE...EXPECT A QUICK BUILDING OF THE SEAS BY THIS AFTERNOON
WITH 3 TO 5 FT ILM NC WATERS AND 3 TO 4 FT FOR THE ILM SC WATERS.
THE PROGGED AFTERNOON AND EVENING WIND AND SEAS COMBO FORECAST
WILL EXCEED SMALL CRAFT EXERCISE CAUTION THRESHOLDS FOR THE ILM NC
WATERS. WILL ISSUE THE SCEC FOR THE HOURS BETWEEN NOON TODAY
THROUGH 6 AM SUNDAY. A PINNED SEA BREEZE COULD PRODUCE A SLIGHT
BACKING OF THE WINDS NEAR SHORE TO S-SSW THIS AFTERNOON AND EARLY
EVENING. THE RELATIVELY COOLER NEAR SHORE WATERS...60S SSTS...WILL
HAVE A TREND TO WEAKEN THUNDERSTORMS THAT MOVE OFF THE MAINLAND
LATER TODAY. WILL HIGHLIGHT IN THE HWO FOR THE THREAT FOR 25 TO 35
KT WIND GUSTS FROM CONVECTION MOVING OFF THE MAINLAND.
.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 3 AM SATURDAY...A COLD FRONT WILL CROSS THE WATERS EARLY
SUNDAY WITH WINDS SHIFTING FROM SOUTHWEST TO NORTH. WIND SPEEDS WILL
REMAIN TEPID WITH THE WIND SHIFT...ON THE LOWE SIDE OF 10-15 KNOTS
UNTIL MONDAY WHEN A SECONDARY SHORTWAVE WITH DECENT COLD AIR
ADVECTION ARRIVES. SPEEDS AT THIS TIME WILL INCREASE BRIEFLY TO
15-20 KNOTS. BY TUESDAY MORNING...SPEEDS WILL LIKELY DROP A COUPLE
OF KNOTS. SIGNIFICANT SEAS WILL HOVER IN A 2-4 FOOT RANGE WITH THE
HIGHER VALUES MAINLY CONFINED TO THE OUTER WATERS.
.LONG TERM /TUESDAY THROUGH WEDNESDAY/...
AS OF 3 AM SATURDAY...HIGH PRESSURE WILL MOVE QUICKLY FROM THE
APPALACHIANS TO OFF THE SOUTHEAST COAST BY THE END OF THE PERIOD.
NORTHERLY WINDS WILL QUICKLY BACK TO A WEAK...LESS THAN TEN KNOTS...
SOUTHWESTERLY DIRECTION BY MIDDAY WEDNESDAY. THE DEVELOPMENT OF A
PIEDMONT TROUGH EARLY THURSDAY WHICH IS MORE INDICATIVE OF A MID
SUMMER PATTERN WILL INCREASE THE GRADIENT BACK TO THE HIGHER END OF
A 10-15 KNOT RANGE. SEAS WILL BE THE HIGHEST EARLY WITH SOME FOUR
FOOTERS ACROSS THE OUTER WATERS. HEIGHTS REALLY DIMINISH WEDNESDAY
BEFORE INCREASING ONCE AGAIN EARLY THURSDAY.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...DCH
NEAR TERM...MBB/DCH
SHORT TERM...SHK
LONG TERM...SHK
AVIATION...MBB/DL
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
640 PM EDT SAT MAY 11 2013
.SYNOPSIS...
A COLD FRONT CROSSING NORTHWEST OHIO WILL MOVE EAST OF THE AREA
TONIGHT. CHILLY HIGH PRESSURE FROM CENTRAL CANADA WILL BUILD OVER
THE REGION BY MONDAY. A WARM FRONT WILL DEVELOP OVER THE MIDWEST
ON TUESDAY.
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
NO MAJOR CHANGES FOR THE EARLY EVENING UPDATE. MADE "SHOWERS
LIKELY" FOR MOST OF THE NORTHWEST OHIO ZONES SINCE THE FRONT IS
NOT FAR AWAY. THE ACTUAL TIME LENGTH OF THE SHOWERS WILL BE
SHORT...LESS THAN AN HOUR. ALSO ISSUED A"NOWCAST" MENTIONING THE
GUSTY NATURE OF THE SHOWERS. GUSTS OF 35 TO 40 MPH POSSIBLE.
THE COLD FRONT WILL WORK ITS WAY ACROSS THE AREA THIS EVENING. THE
TROUGH ALOFT IS SHARP AND THERE IS A LOT OF MOMENTUM TO THE FRONT.
SP DESPITE COMING INTO AN AREA OF STABLE AIR...THINK THERE IS A
DECENT CHANCE OF A SHOWER IN MOST AREAS ESPECIALLY FARTHER NORTH UP
TOWARD LAKE ERIE AND IN THE HIGHER TERRAIN OF NE OH/NW PA. DID NOT
MENTION THUNDER ALTHOUGH AN ISOLATED FLASH OF LIGHTNING NOT OUT OF
THE QUESTION. SOME OF THE SHOWERS WILL BE GUSTY...WITH A 35 KNOT
LOW LEVEL NORTHWEST JET AND STRONG COLD ADVECTION FOLLOWING THE
FRONT. DRIER AIR AND SUBSIDENCE WILL ALSO FOLLOW THE FRONTAL PASSAGE
AND EXPECT CLEARING FROM WEST TO EAST. LOWS WILL DROP INTO THE UPPER
30S MOST AREAS...LOWER/MID 40S NEAR LAKE ERIE. TAKE THE COAT IF YOU
ARE GOING TO BE OUT LATER TONIGHT OR EARLY SUNDAY MORNING.
&&
.SHORT TERM /6 AM SUNDAY MORNING THROUGH TUESDAY NIGHT/...
WITH COLD AIR ALOFT...STEEP LAPSE RATES WILL DEVELOP SUNDAY...
ESPECIALLY WITH A LITTLE MORNING SUNSHINE HEATING UP THE BOUNDARY
LAYER. CUMULUS WILL BUILD AND A FEW SHOWERS WILL DEVELOP... MAINLY
IN AND NEAR THE SNOWBELT OF NE OH/NW PA.
USED THE RAW GFS DATA FOR THE HIGHS SUNDAY...THE MOS GUIDANCE IS
STRONGLY BIASED BY CLIMATOLOGY THIS TIME OF YEAR. IT GAVE UPPER 40S
AND LOWER 50S...A FEW DEGREES BELOW GUIDANCE WHICH SEEMS REASONABLE.
A BRISK NORTHWEST WIND WILL COMPOUND THE CHILL. 850MB TEMPERATURES
WILL DROP TO -4 TO -6C.
THE CENTER OF THE SURFACE HIGH WILL STAY TO THE WEST SUNDAY NIGHT
AND IT WILL TAKE A WHILE FOR THE CUMULUS/STRATOCUMULUS TO DISSIPATE.
THE WIND WILL TAKE A WHILE TO SETTLE. NOT THE BEST CONDITIONS FOR
FROST OR RADIATIONAL COOLING. THAT BEING SAID...THE ACTUAL AIR
TEMPERATURES WILL DROP PRETTY CLOSE TO FREEZING EXCEPT NEAR THE LAKE
ERIE LAKE SHORE. WE PROBABLY WILL NOT SEE AN EXTENDED PERIOD OF
HOURS AT OR BELOW FREEZING AND WILL NOT ISSUE A FREEZE WATCH BUT WE
COULD JUST TOUCH FREEZING IN MANY SPOTS FOR LOWS. THINK THE BEST
APPROACH IS JUST TO KEEP FORECASTING FROST AND THEN ISSUE A FROST
ADVISORY WITH THE SUNDAY FORECAST FOR SUNDAY NIGHT. THE SNOWBELT AND
LAKESHORE WILL PROBABLY NOT SEE MUCH IN THE WAY OF FROST SUNDAY
NIGHT BUT IT COULD BE COLD ENOUGH FOR A FEW WET SNOW FLAKES TO MIX
WITH THE REMAINING SHOWERS.
THE RIDGE WILL BUILD IN ON MONDAY. FAIR WEATHER CUMULUS AND
STRATOCUMULUS AGAIN ARE LIKELY. HIGHS AGAIN BELOW NORMALS...IN THE
50S WITH SOME UPPER 40S EXTREME NE OH/NW PA. THE COLDEST LOWS ON
MONDAY NIGHT WILL SWITCH FROM NW OHIO TO EXTREME NE OH/NW PA. WILL
CONTINUE TO MENTION FROST FOR MONDAY NIGHT NE OH/NW PA.
SOME WARM ADVECTION CLOUDS ARE PROGGED TO SPREAD IN LATE MONDAY
NIGHT AND TUESDAY. A SPRINKLE OR BRIEF SHOWER CAN SOMETIMES OCCUR
WITH THESE DIFFERENTIAL ADVECTION SYSTEMS AND WILL HAVE A SLIGHT
CHANCE OF A SHOWER IN THE FORECAST TUESDAY. WILL AGAIN KEEP TEMPS A
LITTLE BELOW GUIDANCE TUESDAY...MOSTLY UPPER 50S AND LOWER 60S...
BASED ON THE INCREASING CLOUDS AND BIAS TO THE GUIDANCE THIS
TIME OF YEAR.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
MODELS ARE NOT QUITE IDENTICAL IN THEIR SOLUTIONS BUT THEY ARE BOTH
HINTING AT A WARM UP AS WE APPROACH THE MIDDLE OF NEXT WEEK. BROAD
UPPER LEVEL RIDGE IS PROGGED TO BUILD INTO THE FORECAST AREA BY MID
WEEK AND THEN FLATTEN TO BECOME ZONAL ACROSS THE ENTIRE UNITED
STATES BY THURSDAY. THIS SHOULD HELP BRING A BOOST OF WARMER AIR
INTO THE FORECAST AREA THAT WILL LAST RIGHT ON INTO THE END OF THE
WEEK AND WEEKEND. THERE IS NO INDICATION THAT ANY STRONG SURGES OF
COLD AIR WILL SLIDE SOUTH INTO THE FORECAST AREA DURING THIS PERIOD
AND LETS HOPE THIS IS THE LAST ONE.
ONE ISSUE WE WILL HAVE TO CONTEND WITH IS THE FACT THAT WITH THE
WARMER AIR AND HIGHER DEW POINTS...THE THREAT FOR PRECIPITATION WILL
INCREASE. THE OTHER FACTOR IS THE POTENTIAL FOR SOME KIND OF
BOUNDARY...WHETHER IT BE A STATIONARY FRONT OR WARM FRONT...WILL
LINGER AROUND THE REGION. THIS COULD VERY WELL BE THE FOCUSING
MECHANISM THAT COULD PRODUCE A CHANCE FOR SHOWERS AND THUNDERSTORMS
FOR EACH DAY DURING THE PERIOD.
DUE TO THE FACT THAT WE ARE IN MID MAY NOW AND THE SUN ANGLE IS
HIGH...THERE EXISTS THE POTENTIAL FOR TEMPERATURE BUSTS ON THE LOW
END THROUGH THIS PERIOD. WE COULD POSSIBLY SEE TEMPERATURES IN THE
80S EACH DAY RATHER THAN THE 70S FOR HIGHS. BUT...TO REMAIN
CONSISTENT AND COLLABORATED...WILL ERR ON THE SIDE OF LOWER END
UNTIL GET GET A BETTER FIX ON THE MODELS EXPECTED SOLUTION AFTER MID
WEEK.
&&
.AVIATION /00Z SUNDAY THROUGH THURSDAY/...
COLD FRONT NOW ENTERING NWRN OHIO AND BY 00Z SHOULD BE EAST OF
KTOL SO WILL START OUT KTOL AND KFDY IN POST FRONT NWLY FLOW AND
MVFR CIGS FOR A COUPLE HOURS AND THEN ALLOW CONDITIONS TO GO VFR.
BASED ON HRRR TIMING WILL BRING FRONT THROUGH KMFD AT 01Z AND KCLE
AT 0130Z. FRONT SHOULD REACH KYNG AROUND 03Z. EXPECT AN HOUR OR
TWO OF GUSTY WNW FLOW THEN DIURNAL DECREASE TO ABOUT 10KTS OR SO.
EXPECT VFR CIGS TO DEVELOP MOST LOCATIONS ON SUNDAY WITH POSSIBLY
SOME MVFR IN SCATTERED SHOWERS OFF THE LAKE EXTREME NERN OHIO AND
NWRN PA. SUNDAY SHOULD BE FAIRLY WINDY WITH WNW FLOW GUSTING 25 TO
30KTS.
.OUTLOOK...NON VFR POSSIBLE SUNDAY NIGHT AND MONDAY IN NE OH/NW
PA. ALSO POSSIBLE TUESDAY NIGHT.
&&
.MARINE...
COLD FRONT IS EXPECTED TO SWEEP EAST ACROSS THE LAKE THIS EVENING.
THIS FRONT WILL HAVE A BIT OF A PRESSURE WAVE WITH IT AND EXPECT
WINDS TO JUMP UP ALONG THE BOUNDARY. THE WINDS SHOULD DIMINISH A BIT
OVERNIGHT AND THEN PICK UP AGAIN AS MIXING TAKES PLACE DURING THE
DAY TOMORROW. WINDS COULD VERY WELL REACH 30 KNOTS ON THE LAKE AND
POTENTIALLY POKE INTO GALE FORCE TERRITORY FOR A SHORT PERIOD.
SO...FOR NOW WILL LEAVE GALE FORCE WINDS OUT OF THE FORECAST SINCE
THE DURATION SHOULD BE VERY SHORT. HOWEVER...WILL GO WITH A SMALL
CRAFT ADVISORY FOR LATER THIS AFTERNOON AND CONTINUE IT THROUGH
ABOUT MID DAY ON MONDAY. MAY NEED TO EXTEND IT FURTHER ON MONDAY FOR
THE EASTERN PORTIONS OF THE LAKE.
AS HIGH PRESSURE BUILDS EAST TOWARD THE AREA...A GRADUAL DECREASE IN
THE WINDS CAN BE EXPECTED FOR MONDAY INTO TUESDAY. HOWEVER...AS HIGH
PRESSURE MOVES EAST OF THE LAKE...WINDS WILL BEGIN TO PICK BACK UP
AGAIN OUT OF THE SOUTH TO SOUTHWEST WEDNESDAY AND THURSDAY.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 2 PM EDT MONDAY FOR LEZ142>149.
&&
$$
SYNOPSIS...KOSARIK
NEAR TERM...KOSARIK
SHORT TERM...KOSARIK
LONG TERM...LOMBARDY
AVIATION...TK
MARINE...LOMBARDY
FORECAST DISCUSSION FOR ROUTINE AFTERNOON FORECAST ISSUANCE
.SHORT TERM...TONIGHT AND SUNDAY
ISSUED AT 228 PM CDT SAT MAY 11 2013
THE LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW SURFACE LOW
PRESSURE AND COLD FRONT ACROSS LOWER MICHIGAN THIS AFTERNOON.
BEHIND THE FRONT...A DEEP SHORTWAVE TROUGH COMBINED WITH STEEPENING
LOW LEVEL LAPSE RATES AND AMPLE LOW LEVEL MOISTURE ARE GENERATING
SCATTERED RAIN/SNOW/SLEET SHOWERS OVER EASTERN MINNESOTA TO CENTRAL
WISCONSIN...WHICH SHOULD ADVECT INTO EASTERN WISCONSIN LATER THIS
AFTERNOON. SOLID STRATUS DECK HAS HAD A DIFFICULT TIME ADVECTING
SOUTHWARD...BUT NOW EXTENDS FROM NORTHERN WISCONSIN TO HUDSON BAY.
STILL EXPECT THIS STRATUS DECK TO SAG SOUTH FOR THE REST OF THE
AFTERNOON...DRIVEN BY GUSTY NNW WINDS. FORECAST CONCERNS ARE
PRECIP TRENDS AND TEMPS...INCLUDING FROST/FREEZE HEADLINES.
TONIGHT...THE STRONG SHORTWAVE TROUGH WILL MOVE EAST OVER THE
CENTRAL GREAT LAKES THIS EVENING AND INTO FAR EASTERN ONTARIO
OVERNIGHT. BEHIND THE SHORTWAVE...A WIDESPREAD STRATUS DECK OVER
NORTHERN WISCONSIN AND ONTARIO SHOULD ADVECT SOUTH WITH THE HELP OF
MODERATELY STRONG NORTHERLY FLOW AND INCREASING INSTABILITY OF LAKE
SUPERIOR. WITH CYCLONIC FLOW AND COLD ADVECTION...TRENDED
CONSIDERABLY MORE CLOUDY WITH THE SKY COVER TONIGHT. STILL THINK
WILL SEE CLEARING SKIES AFTER MIDNIGHT OVER CENTRAL AND NORTHEAST
WISCONSIN AS MOISTURE IN THE COLUMN DRIES OUT. TEMPS THIS MORNING
OVER NORTHERN MINNESOTA WERE IN THE 32-34 DEGREE RANGE...WHICH WILL
BE THE AIRMASS ADVECTING INTO THE AREA TONIGHT. WITH NO CHANCE OF
DECOUPLING AND CLOUDS POTENTIALLY STICKING AROUND LONGER...HAVE
RAISED LOW TEMPS TOWARDS THE ECMWFBC GUIDANCE...WHICH IS USUALLY ONE
OF THE BETTER PERFORMING TEMP GUIDANCES. SINCE FROST IS A MINIMAL
CONCERN DUE TO WINDS REMAINING UP...HEADLINES ARE REALLY A FREEZE OR
NO FREEZE SCENARIO. WITH TEMPS ONLY BRIEFLY REACHING 32 DEGREES
LATE TONIGHT IN CENTRAL WISCONSIN...COORDINATION RESULTED IN A
DECISION TO GO WITH NO HEADLINES TONIGHT...BUT WILL STILL ADVISE
PEOPLE TO TAKE PRECAUTIONS WITH THEIR SENSITIVE PLANTS OVER CENTRAL
WISCONSIN IN THE HWO...IN CASE TEMPS DO FALL MORE THAN EXPECTED.
WILL GO WITH LOWS IN THE UPPER 20S NORTH...TO 32 DEGREES OVER
CENTRAL WISCONSIN...TO THE MID 30S NEAR LAKE MICHIGAN.
SUNDAY...LOW PRESSURE WILL MOVE FURTHER EAST INTO QUEBEC WHILE HIGH
PRESSURE BUILDS INTO THE REGION. THINK BROKEN CLOUD COVER WILL
CONTINUE TO RESIDE OVER NORTH-CENTRAL WISCONSIN TO START THE MORNING
WHICH SHOULD RETREAT TO THE NORTH. WITH DIURNAL HEATING
THOUGH...RATHER FLAT DIURNAL CU SHOULD DEVELOP BY LATE MORNING AND
THEN MIX OUT IN THE AFTERNOON. HIGHS TO TOP OUT IN THE MIDDLE 40S TO
LOWER 50S.
.LONG TERM...SUNDAY NIGHT THROUGH SATURDAY
ISSUED AT 228 PM CDT SAT MAY 11 2013
MAIN FCST CONCERNS INCLUDE FREEZE HEADLINES FOR SUNDAY NIGHT...THE
POTENTIAL FOR SEVERE TSTMS LATE TUESDAY INTO TUESDAY NIGHT...AND
TEMPERATURES THROUGH THE PERIOD.
SFC HIGH PRESSURE WILL RESIDE OVER THE FORECAST AREA ON SUNDAY NIGHT.
CLEAR SKIES AND LIGHT/CALM WINDS WILL ALLOW TEMPS TO DROP BLO FREEZING
ACROSS ALL BUT THE LAKESHORE AREAS. WE HAVE NOT STARTED UP FROST/FREEZE
HEADLINES OVER NORTHERN WI YET...SO NO HEADLINES THERE DESPITE MIN TEMPS
IN THE LOW TO MID 20S. WILL KEEP THE FREEZE WATCH GOING ACROSS THE
SOUTHERN HALF OF THE CWA...AND WOULD ANTICIPATE THAT THIS WILL BE
UPGRADED A FREEZE WARNING WITH THE 4 AM SUNDAY FCST PACKAGE.
AN UPPER LEVEL RIDGE WILL BUILD OVER THE REGION MONDAY INTO TUESDAY...
WITH LOW-LEVEL WAA KICKING IN MONDAY INTO MONDAY NIGHT. THE WAA SURGE
WILL BRING INCREASING CLOUDS...WITH A CHANCE OF SHOWERS OVER OUR WSTRN
COUNTIES ON MONDAY...AND OVER THE ENTIRE CWA MONDAY NIGHT.
ON TUESDAY...A WARM FRONT IS EXPECTED TO LIFT NORTHWARD INTO CENTRAL
WI DURING THE AFTERNOON. TEMPERATURES WILL BE A TOUGH CALL...AS CLOUDS
AND EAST WINDS NORTH OF THE FRONT COULD HOLD READINGS IN THE 50S/60S
OVER THE LAKESHORE AND FAR NE WI...WHILE MIXING THROUGH 850 MB OVER
CENTRAL WI WOULD BE SUPPORTIVE OF HIGHS IN THE UPPER 80S/LOWER 90S
IN THE FAR SW PART OF THE CWA. NOT CONFIDENT ENOUGH TO GO WITH THAT
LARGE OF A GRADIENT OVER THE FORECAST AREA...BUT WILL HAVE UPPER 50S/
LOWER 60S NEAR THE LAKE...WITH INLAND LOCATIONS RANGING FROM THE UPPER
60S OVER FAR NE WI TO THE LOWER 80S IN CENTRAL WI.
WILL CARRY A SLGT CHC/CHANCE OF TSTMS NORTH OF THE WARM FRONT ON
TUESDAY...AS THE MODELS SHOW A SURGE OF INSTABILITY ARRIVING DURING
THE AFTERNOON...BUT ALSO SOME POTENTIAL CAPPING. AM CONCERNED ABOUT
THE POTENTIAL FOR SVR TSTMS TUESDAY NIGHT...AS THE WARM FRONT LIFTS
NORTH...FOLLOWED BY THE COLD FRONTAL PASSAGE OVERNIGHT. MODELS ARE
IN DECENT AGREEMENT ON MUCAPE INCREASING TO 1500-2000 J/KG...
ALONG WITH DEEP LAYER SHEAR OF 45-55 KNOTS...0-3 KM HELICITIES OF
300-500...AND MID-LEVEL LAPSE RATES INCREASING TO 7-7.5 C/KM. THE
GFS MODEL SEEMS TO DEPICT THIS BEST...WITH A BULLSEYE OF QPF OVER
THE NE HALF OF THE FORECAST AREA. WILL ADD A MENTION OF POSSIBLE
SVR TSTMS LATE TUESDAY INTO TUESDAY NIGHT TO THE HAZARDOUS WEATHER
OUTLOOK.
THE COLD FRONT IS EXPECTED TO SHIFT SOUTH OF THE AREA WEDNESDAY INTO
THURSDAY NIGHT...RESULTING IN A GENERAL LULL IN THE PCPN. THE FRONT
WILL LIFT BACK TO THE NORTH LATE IN THE WEEK...BRINGING THE CHANCE
OF TSTMS BACK INTO THE REGION ON FRI/SAT.
ALTHOUGH TEMPERATURES WILL START OFF ON THE COOL SIDE...THEY SHOULD
AVERAGE ABOVE NORMAL FROM TUESDAY THROUGH SATURDAY.
&&
.AVIATION...FOR 18Z TAF ISSUANCE
ISSUED AT 1237 PM CDT SAT MAY 11 2013
A STRONG UPPER LEVEL DISTURBANCE WILL PASS ACROSS THE
AREA THROUGH THIS EVENING. WIDESPREAD LOW END VFR CIGS UPSTREAM
COMBINED WITH AFTERNOON INSTABILITY WILL LEAD TO ISOLATED TO
SCATTERED RAIN SHOWERS FROM EARLY THIS AFTERNOON THROUGH ABOUT
MID-EVENING. SNOW WILL LIKELY MIX IN WITH THE RAIN OVER N-C
WISCONSIN...WHICH COULD DROP VSBYS TO MVFR LEVELS.
OTHERWISE...GUSTY NW WINDS WILL PREVAIL UNTIL SUNSET. CLOUDS TO
STICK AROUND OVER N-C WISCONSIN FOR MUCH OF THE NIGHT AS FLOW WILL
REMAIN OFF LAKE SUPERIOR. NOT AS CLEAR CUT OVER CENTRAL AND
NORTHEAST WISCONSIN. SHARP CYCLONIC FLOW AND COLD LOW LEVEL
TEMPERATURES ARGUES FOR CLOUDS TO STICK AROUND LONGER THAN WHAT THE
MODELS SUGGEST. WILL TREND THAT DIRECTION...THOUGH CIGS SHOULD
REMAIN VFR. A STEADY WIND OF AROUND 10 KTS SHOULD PREVENT FROST
FROM FORMING THOUGH TEMPS WILL BE AROUND FREEZING. SCT-BKN CLOUD
COVER TOMORROW BUT NW WINDS WILL REMAIN GUSTY.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
FREEZE WATCH FROM LATE SUNDAY NIGHT THROUGH MONDAY MORNING FOR
WIZ020-030-031-035>040-045-048>050-073-074.
&&
$$
SHORT TERM.....MPC
LONG TERM......KIECKBUSCH
AVIATION.......MPC
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1234 PM CDT SAT MAY 11 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 343 AM CDT SAT MAY 11 2013
MAIN FORECAST CONCERNS ARE ON WINDS TODAY...AND IF FROST OR FREEZE
CONDITIONS CAN OCCUR TONIGHT.
CURRENTLY AS OF 08Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS
SHOWED STRONG RIDGING ALONG THE WEST COAST OF NORTH AMERICA AND A
SHARP/POTENT UPPER TROUGH DROPPING INTO NORTHERN MINNESOTA AND
NORTHWEST ONTARIO. A NARROW BAND OF SHOWERS CONTINUE ON RADAR
IMMEDIATELY AHEAD OF THE UPPER TROUGH...RESULTING FROM STRONG DPVA
AS WELL AS LOW LEVEL FRONTOGENETIC FORCING BEHIND A COLD FRONT. THIS
COLD FRONT EXTENDED FROM CENTRAL LAKE SUPERIOR TO WINONA MN AND DES
MOINES IA. PLENTY OF DRY AIR EXISTS BOTH AHEAD AND BEHIND THE COLD
FRONT...NOTED BY 00Z SOUNDINGS FROM MPX AND BIS. THE 00Z INL
SOUNDING WAS MOST REPRESENTATIVE OF THE ENVIRONMENT WITH THE NARROW
BAND OF SHOWERS...REFLECTING HIGH CLOUD BASES AND SATURATION MAINLY
FROM 750-550MB. THE HIGH CLOUD BASES COMBINED WITH THE LACK OF
MOISTURE KEEPING RAINFALL AMOUNTS VERY LOW WITH THE BAND OF SHOWERS.
AS EXPECTED WITH A HIGHLY AMPLIFIED UPPER TROUGH...A STRONG PRESSURE
RISE OF ALMOST 2 MB /1 HR WAS PRESENT BEHIND THE FRONT. THIS
PRESSURE RISE HAS RESULTED IN GUSTS OF 25-35 KT IMMEDIATELY AFTER
THE FRONTAL PASSAGE. A TIGHT PRESSURE GRADIENT EXISTS TOO BEHIND THE
FRONT...AHEAD OF CANADIAN HIGH PRESSURE IN SASKATCHEWAN. THE
BLUSTERY NORTHWEST WINDS ARE BRINGING UNSEASONABLY COOL AIR
SOUTHEAST...WITH 850MB TEMPS AT 00Z OF -5C AT THE PAS MANITOBA.
THE POTENT UPPER TROUGH APPROACHING THE FORECAST AREA IS PROGGED TO
ENCOMPASS MUCH OF THE WESTERN GREAT LAKES REGION BY THIS
EVENING...THEN BEGIN A SLOW MARCH EAST. THIS UPPER TROUGH WILL LEAD
TO A VARIETY OF CONCERNS FOR THE SHORT TERM PERIOD.
1. WINDS. AFTER THE COLD FRONT PASSES THROUGH THE REST OF THE
FORECAST AREA EARLY THIS MORNING...A TIGHT PRESSURE GRADIENT IS
PROGGED TO REMAIN IN PLACE PRETTY MUCH THROUGH TONIGHT. THE SURFACE
HIGH SEEN IN SASKATCHEWAN STAYS OFF WELL TO THE WEST...DROPPING DOWN
INTO SOUTHWEST MN BY 12Z SUNDAY. DEEP MIXING COMBINED WITH COLD
ADVECTION...A UNIDIRECTIONAL NORTHWEST FLOW AND STRONG SUBSIDENCE
FROM THE UPPER TROUGH CROSSING WILL RESULT IN A WINDY DAY TODAY.
WINDS AT THE TOP OF THE MIXED LAYER...AROUND 775MB...ONLY TOP OUT
AROUND 40 KT. MIXING THIS DOWN RESULTS IN MAX GUSTS IN THE 30-35 KT
RANGE...BELOW ADVISORY CRITERIA. WINDS ARE LIKELY TO DIMINISH THIS
EVENING WITH LOSS OF DAYTIME HEATING...BUT THERE IS NO CHANCE TO
DECOUPLE TONIGHT.
2. TEMPERATURES. 850MB TEMPS ARE PROGGED TO COOL TO AROUND -2C BY
18Z...OR 1.5-2 STANDARD DEVIATIONS BELOW NORMAL. AS MENTIONED IN THE
WINDS...THE STRONG MAY SUN WILL EASILY ALLOW MIXING UP TO 850MB AND
BEYOND...WHICH YIELDS HIGHS MAINLY IN THE LOW TO MID 50S. COLD
ADVECTION CONTINUES INTO TONIGHT AS 850MB TEMPS PLUNGE TO -4 TO -6C.
THE QUESTION IS IF THE WINDS MAY KEEP THE BOUNDARY LAYER MIXED
ENOUGH TO PREVENT TEMPERATURES FROM FALLING MUCH BELOW FREEZING. THE
11.00Z REGIONAL CANADIAN...ECMWF AND HIRES ARW KEEPS TEMPERATURES AT
OR ABOVE FREEZING ACROSS THE FORECAST AREA...WHEREAS THE 11.00Z NAM
HAS READINGS MORE IN THE 25 TO 30 RANGE. MOS GUIDANCE AND THE 11.00Z
GFS SPLIT THE DIFFERENCE AND KEEPS THE COLDEST TEMPERATURES OVER
CENTRAL WISCONSIN. TYPICALLY THE REGIONAL CANADIAN IS COLD FOR
LOWS...SO IT IS SURPRISING TO SEE IT BEING ONE OF THE WARMER MODELS.
GIVEN THE WIND...HAVE LEANED MORE TOWARDS THE 11.00Z GFS/HIRES ARW
AND REGIONAL CANADIAN IDEA. UPSTREAM OVER NORTH DAKOTA...
TEMPERATURES ARE STILL MOSTLY ABOVE FREEZING AS WELL AS OF 08Z.
3. FROST/FREEZE TONIGHT. VERY TRICKY AS NOTED BY THE TEMPERATURE
DISCUSSION ABOVE. WITH THE WIND AND DRY AIR ADVECTION TAKING PLACE
THROUGH TONIGHT...SEEMS HARD TO GET MUCH FROST DEVELOPMENT UNLESS
YOU ARE IN A REALLY SHELTERED LOCATION FROM THE NORTHWEST WIND.
RELATIVE HUMIDITIES LOOK TO STRUGGLE TO RISE TO 75 PERCENT. IN
ADDITION...WITH THE CONCERN ABOUT TEMPERATURES NOT FALLING BELOW
FREEZING...MAY NOT SEE FREEZE CONDITIONS EXCEPT PERHAPS IN TAYLOR
COUNTY. EVEN IF WE SEE FREEZE CONDITIONS...THEY MAY ONLY LAST AN
HOUR. THUS...HAVE NOT ISSUED ANY FROST/FREEZE HEADLINES FOR TONIGHT.
4. PRECIPITATION. ONGOING SHOWERS SHOULD PUSH SOUTHEAST OF THE AREA
BY 12Z THIS MORNING. UPSTREAM...THERE IS A CLUSTER OF CLOUDS ALONG
WITH A FEW SHOWERS AROUND THE GRAND FORKS AND FARGO AREAS OF NORTH
DAKOTA. THESE ARE ASSOCIATED WITH A SHORTWAVE WITHIN THE TROUGH.
GOOD MODEL AGREEMENT EXISTS OF THE SHORTWAVE AND CLOUDS DROPPING
THROUGH SOUTHERN MN AND NORTHERN IA TODAY. HAVE INCLUDED A FEW
SPRINKLES AS WELL AS THERE IS CONCERN THE SHOWERS MAY DRY UP SOME AS
HRRR RUNS SUGGEST. A FEW OTHER DIURNALLY DRIVEN SHOWERS/SPRINKLES
ASSOCIATED WITH THE COLD POOL MAY FORM TOO ACROSS TAYLOR/CLARK
COUNTIES.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 343 AM CDT SAT MAY 11 2013
SUNDAY THROUGH MONDAY NIGHT...THE UPPER RIDGE THAT HAS BEEN BUILDING
UP ALONG THE WEST COAT OF THE U.S. IS PROGGED BY ALL MODELS TO GET
PUSHED EAST DURING THIS PERIOD...IN RESPONSE TO A STRONG SHORTWAVE
COMING INTO THE PACIFIC NORTHWEST LATE MONDAY. THIS UPPER RIDGE WILL
HELP TO KEEP THIS PERIOD OF UNSEASONABLY COOL AIR BRIEF. BY LATE
SUNDAY NIGHT...WESTERN PORTIONS OF THE FORECAST AREA SHOULD START
GETTING INTO THE WARM ADVECTION SETUP. UNTIL THEN...MAIN CONCERN IS
FROST/FREEZE SUNDAY NIGHT. MODELS PROG THE SURFACE CANADIAN HIGH
PRESSURE RIDGE TO BE CENTERED OVER THE ENTIRE FORECAST AREA AT 06Z
MONDAY...LEADING TO CLEAR SKIES AND LIGHT WINDS. GIVEN A COOL SUNDAY
TO BEGIN WITH...SITUATION SHOULD BE VERY FAVORABLE FOR FROST/FREEZE
CONDITIONS ACROSS MUCH OF THE FORECAST AREA...ESPECIALLY OVER
WISCONSIN. LEANED TOWARDS THE COOLER SIDE OF GUIDANCE FOR LOWS...
RESULTING IN THE NEED FOR A FREEZE WATCH FOR COUNTIES ALONG AND
NORTHEAST OF I-94. THE WARM ADVECTION MONDAY INTO MONDAY NIGHT IS
INTERESTING AS 850MB TEMPS CLIMB ABOUT 12C FROM 12Z MONDAY TO 12Z
TUESDAY. GOOD MODEL AGREEMENT EXISTS THAT AN AREA OF MID AND HIGH
CLOUDS WILL DEVELOP IN RESPONSE TO THIS WARM ADVECTION. ISENTROPIC
LIFT FIELDS ON THE 295 AND 300K SURFACE SHOW AN AREA OF LIFT
OCCURRING WITHIN THESE CLOUDS...MARCHING EAST WITH TIME. THE 11.00Z
GFS/ECMWF AND 11.03Z SREF ALL DEVELOP PRECIPITATION...WHILE THE
11.00Z NAM IS DRY. THE NAM DOES NOT DEVELOP PRECIPITATION BECAUSE OF
DRY LOW LEVELS ABSORBING THE RAIN...WHICH THE NAM TENDS TO OVERDO.
THUS...HAVE KEPT AND RAISED SLIGHTLY THE PRECIPITATION CHANCES FOR
MONDAY AFTERNOON AND EVENING. DID TAKE OUT THE THUNDER...THOUGH...AS
NO INSTABILITY EXISTS.
FOR THE REST OF THE WEEK...
FOCUS REMAINS ON HIGH TEMPERATURES ON TUESDAY. 11.00Z CANADIAN AND
ECMWF HAVE WENT BACK AND NOW SHOW A SURFACE WARM FRONT PROGRESSING
THROUGH THE AREA QUICKER...WHICH ALLOWS WARMER AIR TO PUSH INTO THE
AREA DURING THE DAY. THE 11.00Z GFS HAS STAYED PERSISTENT. ALL
MODELS NOW SHOW 850MB TEMPS CLIMBING TO 18C OVER CENTRAL WISCONSIN
TO 24C NEAR I-35 BY 00Z...WHICH ARE 2.5 STANDARD DEVIATIONS ABOVE
NORMAL. ONCE YOU GET TO 2.5...CONCERN INCREASES OF REACHING RECORDS.
PROBLEM IS MOST MODEL GUIDANCE HAS TOO MUCH MOISTURE IN THE BOUNDARY
LAYER. THE SCENARIO IS THE GULF OF MEXICO IS CUT OFF BY THE CURRENT
CANADIAN HIGH DROPPING DOWN TO THE GULF COAST...AND CROPS THAT ARE
BEHIND SCHEDULE DUE TO THE COOL SPRING. MODELS ARE TRYING TO GET THE
MOISTURE FROM EVAPOTRANSPORATION. WITH TOO MUCH MOISTURE IN THE
BOUNDARY LAYER...TEMPERATURES CANNOT RISE ENOUGH FROM MIXING.
THUS...HAVE STAYED PRETTY CLOSE TO THE PREVIOUS FORECAST AND BOOSTED
READINGS A FEW DEGREES WEST OF THE MISSISSIPPI RIVER TO ACCOUNT FOR
THE GROWING CONSENSUS ON THE WARM AIR TIMING. TEMPERATURES MAY STILL
NEED TO BE RAISED FURTHER.
A COLD FRONT ACCOMPANYING THAT TROUGH COMING INTO THE PACIFIC
NORTHWEST MONDAY IS SLATED TO COME THROUGH THE FORECAST AREA TUESDAY
NIGHT AND WEDNESDAY. FOLLOWED A CONSENSUS BLEND AND HAVE JUST LOW
CHANCES FOR SHOWERS/STORMS AS THE FRONT MOVES THROUGH. BEYOND
WEDNESDAY...THE FORECAST GETS MUDDLED WITH THE 11.00Z ECMWF/CANADIAN
SUGGESTING MORE OF A ZONAL TO SLIGHT UPPER RIDGING PATTERN IN PLACE
AS TROUGHING REFORMS IN THE PACIFIC NORTHWEST. MEANWHILE...THE
11.00Z GFS/GFS ENSEMBLES DEPICT TROUGHING TO FORM AND LINGER AROUND
THE FORECAST AREA. BOTH SITUATIONS SUGGEST A TREND TOWARDS
DRIER...AND THEREFORE THE CHANCES OF PRECIPITATION HAVE BEEN LOWERED
SOME. COULD SEE FINE TUNING TAKING PLACE TO DRY OUT PORTIONS OF THE
WEDNESDAY NIGHT THROUGH FRIDAY PERIOD. OTHERWISE...TEMPERATURES LOOK
COOLER BUT SHOULD STILL STAY NEAR OR ABOVE NORMAL WITH A MOSTLY
PACIFIC FLOW OF AIR.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1234 PM CDT SAT MAY 11 2013
COLDER TEMPERATURES ALOFT COMBINED WITH SOME RESIDUAL LOW LEVEL
MOISTURE WILL RESULT IN ISOLATED TO WDLY SCT SHRA/SHPL THRU THE
EARLY AFTERNOON HOURS TODAY. GIVEN SPOTTY NATURE AND FAST MOVEMENT
OF THESE SHOWERS...ONLY INCLUDED VCSH IN TAFS. THIS MOISTURE WILL
EXIT LATER THIS AFTERNOON...WITH FURTHER DRYING/SUBSIDENCE AND HIGH
PRESSURE BUILDING PRODUCING SKC FOR TONIGHT/SUNDAY. PRESSURE
GRADIENT AND MIXING WILL RESULT IN CONTINUED STRONG/GUSTY NORTHWEST
WINDS INTO EARLY THIS EVENING. WITH LOSS OF DAYTIME HEATING AND
RELAXING OF THE GRADIENT...WINDS TONIGHT/SUN WILL MOSTLY BE IN THE
10-15KT RANGE.
&&
.FIRE WEATHER...
ISSUED AT 343 AM CDT SAT MAY 11 2013
BREEZY NORTHWEST WINDS ARE EXPECTED THIS WEEKEND AHEAD OF A
STRONG AREA OF CANADIAN HIGH PRESSURE OVER SASKATCHEWAN DROPPING
SOUTHEASTWARD. THESE NORTHWEST WINDS ARE GOING TO USHER IN AN
UNSEASONABLY COOL AND DRY AIRMASS INTO THE FORECAST AREA. DEEP
MIXING RESULTING FROM THE STRONG MAY SUN SHOULD ALLOW DEWPOINTS TO
DROP INTO THE MID TEENS TO MID 20S DURING THE AFTERNOON...WHICH
WITH HIGH TEMPERATURES IN THE LOW TO MID 50S...RELATIVE HUMIDITIES
WILL DROP TO 20 TO 30 PERCENT. PRECLUDING A RED FLAG WARNING AT
THIS TIME IS A COMBINATION OF THE COOL TEMPERATURES...THE RECENT
SOAKING RAIN ON THURSDAY RESULTING IN WETTER FUELS...AND GREEN
UP THAT REALLY TOOK OFF THIS WEEK.
HEADING INTO EARLY NEXT WEEK...FOCUS REMAINS ON TUESDAY AS
SOUTHEAST MINNESOTA AND NORTHEAST IOWA BECOME POSITIONED IN A VERY
WARM ENVIRONMENT. TEMPERATURES LOOK TO CLIMB INTO THE MID TO UPPER
80S...AND PERHAPS COULD EVEN CLIMB INTO THE LOW 90S. DEWPOINT
FORECASTS ARE A LITTLE DIFFICULT AT THIS TIME WITH MOST MODELS
APPEARING TO OVERDO THEM...BUT RELATIVE HUMIDITIES SHOULD DROP AT
LEAST TO 35 TO 40 PERCENT. IT IS POSSIBLE THESE COULD END UP LOWER
AS CERTAINTY ON DEWPOINTS INCREASES. WINDS LOOK MARGINAL RIGHT
NOW FOR RED FLAG CONDITIONS. NEEDLESS TO SAY...SOMETHING TO KEEP
AN EYE ON OVER THE NEXT FEW DAYS.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...FREEZE WATCH FROM LATE SUNDAY NIGHT THROUGH MONDAY MORNING FOR
WIZ017-029-034-042>044.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM.....AJ
LONG TERM......AJ
AVIATION.......RRS
FIRE WEATHER...AJ