Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 06/01/13
AREA FORECAST DISCUSSION
NWS SAN FRANCISCO BAY AREA
845 AM PDT THU MAY 30 2013
.DISCUSSION...AS OF 08:31 AM PDT THURSDAY...
FORECAST LOOKS ON TRACK THIS MORNING WITH EARLY MORNING
TEMPERATURES A FEW DEGREES COOLER THAN YESTERDAY AT THIS TIME.
GOOD RADIATIONAL COOLING NIGHT WITH LESS STRATUS THIS MORNING. WRF
MODEL CAPTURED BOUNDARY LAYER RH FIELD PRETTY WELL THIS MORNING
AND RESULTANT AREAS OF STRATUS. MODEL TRENDS TOWARD RAPID STRATUS
CLEARING THIS MORNING...BUT LOOKING AT VISIBLE SATELLITE IMAGERY
WOULD SUGGEST SLIGHTLY SLOWER CLEARING. SAN MATEO COAST AND WEST
SLOPES OF COAST RANGE AS WELL AS MONTEREY BAY SHOULD SEE GRADUAL
DISSIPATION OF LOW CLOUDS THROUGH THE MORNING WITH PRESSURE
GRADIENT BECOMING MORE NORTHERLY. NAM SUGGESTS INCREASING
NORTHERLY GRADIENT THROUGH FRIDAY FROM SFO TO ACV WITH INCREASING
850 MB TEMPERATURES. HIGHS THIS AFTERNOON SHOULD END UP A FEW
DEGREES WARMER INLAND WITH NOT MUCH CHANGE NEAR THE COAST. CURRENT
STATEMENTS STILL ON TRACK HIGHLIGHTING WARM INLAND TEMPERATURES
THIS WEEKEND AND HEIGHTENED FIRE WEATHER CONCERNS.
&&
...TURNING HOT INLAND FRIDAY AND SATURDAY...
.DISCUSSION...AS OF 3:48 AM PDT THURSDAY...MAIN FORECAST FOCUS WILL
DEAL WITH HIGH TEMPERATURE FORECASTS THE NEXT SEVERAL DAYS.
OVERALL IDEA WILL SHOW WARMING TREND STARTING TODAY AND CONTINUING
AT LEAST THROUGH SATURDAY...AND POSSIBLY SUNDAY FOR THE INLAND
VALLEYS. A FEW DAYS AGO THE MODELS WERE HINTING THAT THE THERMAL
TROUGH MAY SHIFT TO THE COAST FRIDAY OR SATURDAY MORNING. LATEST
MODELS SOLUTIONS AREN`T REALLY SHOWING THAT SO THE FLOW AT THE
SURFACE LOOKS TO REMAIN ONSHORE THROUGH THIS EVENT. THEREFORE HOT
WEATHER WILL BE CONFINED TO THE INLAND VALLEYS. THIS WOULD INCLUDE
THOSE LOCATIONS EAST OF THE EAST BAY HILLS AS WELL AS THE NORTH
BAY VALLEYS AND SANTA CLARA VALLEY. EVEN THOUGH ALL LOCATIONS WILL
OBSERVE A NOTED WARMING TREND...THE PRESENCE OF WESTERLY WINDS
THROUGH THE EVENT SHOULD KEEP ANY SERIOUS HEAT IN CHECK FOR
LOCATIONS INSIDE SF BAY AS WELL AS AROUND THE MONTEREY BAY. SO IF
ANYTHING WE SHOULD SET UP SOME WELL DEFINED MICRO-CLIMATES WITH
SOME POTENTIALLY HUGE TEMPERATURE SPREADS ACROSS THE DISTRICT BY
SATURDAY. SHOULD BE ABLE TO SEE TEMPERATURES RANGE FROM 60S AT THE
BEACHES TO AROUND 105 FOR THE WARMEST INLAND SPOTS.
OTHER ITEMS TO MONITOR WILL BE SOME LIGHT TO MODERATE NORTH WINDS
IN THE HILLS LATER FRIDAY NIGHT INTO EARLY SATURDAY AND THEN AGAIN
SATURDAY NIGHT. 850 MB TEMPS SHOULD STAY WELL ABOVE 20 CELSIUS SO
SOME HILL LOCATIONS ABOVE 1500 FEET WILL LIKELY SEE OVERNIGHT LOWS
AROUND 70 DEGREES WITH BREEZY NORTH WINDS AND POOR HUMIDITY
RECOVERY WHICH WILL BECOME A FIRE WEATHER CONCERN.
HOWEVER...SIMILAR TO THE HEAT IT WOULD APPEAR WE`LL STAY OUT OF
ANY WARNING CRITERIA FOR FIRE WEATHER OR HEAT RELATED PRODUCTS AT
THIS TIME. HAVE REFRESHED THE SPECIAL WEATHER STATEMENT TO KEEP
THE MESSAGE GOING FOR OVERALL CHANGE IN THE WEATHER...TO HOTTER
INLAND TEMPS.
ECMWF SOLUTION PINCHES OFF A 500 MB CIRCULATION JUST OFF THE
COAST BY SUNDAY. THIS WILL LIKELY INDUCE SOME SORT OF COASTAL COOLING
TREND IN THE FORM OF MARINE CLOUDS OR A SOUTHERLY WIND REVERSAL.
850 MB TEMPS WILL STAY AROUND 22 CELSIUS THROUGH SUNDAY AFTERNOON
SO ANY INLAND COOLING WILL BE MINOR AT BEST THROUGH THE WEEKEND.
BY MONDAY HEIGHTS WILL DROP...ONSHORE FLOW WILL INCREASE AND 850
MB TEMPS WILL NUDGE DOWNWARD AS WELL WHICH SHOULD LEAD TO A MARKED
INLAND COOLING TREND AS WELL.
FORECAST FOR NEXT WEEKS SHOWS A WEAK CIRCULATION OFF THE COAST
WHICH SHOULD KEEP A WELL DEFINED AND FAIRLY DEEP MARINE LAYER IN
PLACE. ANY CONVECTION WILL LIKELY STAY OVER THE SIERRA EVEN THOUGH
THE GFS WANTS TO SPIT SOME OUT CLOSER TO THE CENTER OF THE LOW. AS
THE CALENDAR TURNS TO JUNE A FORECAST NEAR CLIMATOLOGICAL NORMS
LOOKS PRETTY GOOD.
&&
.AVIATION...AS OF 4:45 AM PDT THURSDAY...MAINLY VFR CONDITIONS
OVER THE TERMINALS THROUGH THE FORECAST AS HIGH PRESSURE BEGINS TO
BUILD OVER THE REGION. PATCHES OF STRATUS FORMED OVER THE MONTEREY
BAY AND SAN MATEO COAST OVERNIGHT...AND ARE LIKELY TO EXPAND
THROUGH SUNRISE...MAINLY IMPACTING THE MONTEREY BAY TERMINALS.
OTHERWISE...MODERATE ONSHORE FLOW THIS AFTERNOON WITH PATCHY
STRATUS AGAIN FRIDAY MORNING.
VICINITY OF KSFO...VFR CONDITIONS THROUGH THE FORECAST.
STRENGTHENING NORTHERLY GRADIENTS WILL LIKELY KEEP STRATUS OUT OF
THE SF BAY TERMINALS. THERE IS A CHANCE THAT PATCHY STRATUS WILL
IMPACT KOAK THROUGH 17Z. MODERATE WEST WINDS TO 25 KT THIS
AFTERNOON THROUGH THE EARLY EVENING HOURS.
KSFO BRIDGE APPROACH...OCCASIONAL PATCHES OF STRATUS MAY DRIFT
OVER THE APPROACH THROUGH 17Z. LOW CONFIDENCE.
MONTEREY BAY AREA TERMINALS...IFR CIGS THROUGH 17Z. LOW
CONFIDENCE. MOST OF THE SHORT TERM MODELS INITIALIZED POORLY...WITH
ONLY THE LOCAL WRF AND HRRR INDICATING STRATUS MAY DEVELOP
OVERNIGHT. BOTH OF THESE MODELS ARE CONSISTENT IN THE FACT THAT
STRATUS WILL DISSIPATE BY 17Z. OTHERWISE...MODERATE WESTERLY WINDS
THIS AFTERNOON.
&&
.CLIMATE DATA FOR JUNE 1ST...
LOCATION FORECAST NORMAL RECORD TEMPERATURE
SANTA ROSA 92 77 95 1919
SAN RAFAEL 88 73 101 1960
NAPA 91 79 105 1960
SAN FRANCISCO 73 65 90 1989
OAKLAND 80 70 87 1989
LIVERMORE 98 80 105 1938
SANTA CRUZ 85 73 93 1912
SALINAS AIR 78 69 85 1935
.MTR WATCHES/WARNINGS/ADVISORIES...
.TDAY...SCA...PT ARENA TO PT REYES 0-10 NM
SCA...PIGEON PT TO PT PINOS 0-10 NM
SCA...PT ARENA TO PIGEON PT 10-60 NM
SCA...PIGEON PT TO PT PIEDRAS BLANCAS 10-60 NM
GLW...PT PINOS TO PT PIEDRAS BLANCAS 0-10 NM
SCA...PT REYES TO PIGEON PT 0-10 NM
SCA...SF BAY FROM 2 PM
SCA...MRY BAY FROM 2 PM
&&
$$
PUBLIC FORECAST: KBB
AVIATION/MARINE: RILEY
CLIMATE: HENDERSON/LARRY
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AREA FORECAST DISCUSSION
NWS SAN FRANCISCO BAY AREA
453 AM PDT THU MAY 30 2013
...TURNING HOT INLAND FRIDAY AND SATURDAY...
.DISCUSSION...AS OF 3:48 AM PDT THURSDAY...MAIN FORECAST FOCUS WILL
DEAL WITH HIGH TEMPERATURE FORECASTS THE NEXT SEVERAL DAYS.
OVERALL IDEA WILL SHOW WARMING TREND STARTING TODAY AND CONTINUING
AT LEAST THROUGH SATURDAY...AND POSSIBLY SUNDAY FOR THE INLAND
VALLEYS. A FEW DAYS AGO THE MODELS WERE HINTING THAT THE THERMAL
TROUGH MAY SHIFT TO THE COAST FRIDAY OR SATURDAY MORNING. LATEST
MODELS SOLUTIONS AREN`T REALLY SHOWING THAT SO THE FLOW AT THE
SURFACE LOOKS TO REMAIN ONSHORE THROUGH THIS EVENT. THEREFORE HOT
WEATHER WILL BE CONFINED TO THE INLAND VALLEYS. THIS WOULD INCLUDE
THOSE LOCATIONS EAST OF THE EAST BAY HILLS AS WELL AS THE NORTH
BAY VALLEYS AND SANTA CLARA VALLEY. EVEN THOUGH ALL LOCATIONS WILL
OBSERVE A NOTED WARMING TREND...THE PRESENCE OF WESTERLY WINDS
THROUGH THE EVENT SHOULD KEEP ANY SERIOUS HEAT IN CHECK FOR
LOCATIONS INSIDE SF BAY AS WELL AS AROUND THE MONTEREY BAY. SO IF
ANYTHING WE SHOULD SET UP SOME WELL DEFINED MICRO-CLIMATES WITH
SOME POTENTIALLY HUGE TEMPERATURE SPREADS ACROSS THE DISTRICT BY
SATURDAY. SHOULD BE ABLE TO SEE TEMPERATURES RANGE FROM 60S AT THE
BEACHES TO AROUND 105 FOR THE WARMEST INLAND SPOTS.
OTHER ITEMS TO MONITOR WILL BE SOME LIGHT TO MODERATE NORTH WINDS
IN THE HILLS LATER FRIDAY NIGHT INTO EARLY SATURDAY AND THEN AGAIN
SATURDAY NIGHT. 850 MB TEMPS SHOULD STAY WELL ABOVE 20 CELSIUS SO
SOME HILL LOCATIONS ABOVE 1500 FEET WILL LIKELY SEE OVERNIGHT LOWS
AROUND 70 DEGREES WITH BREEZY NORTH WINDS AND POOR HUMIDITY
RECOVERY WHICH WILL BECOME A FIRE WEATHER CONCERN.
HOWEVER...SIMILAR TO THE HEAT IT WOULD APPEAR WE`LL STAY OUT OF
ANY WARNING CRITERIA FOR FIRE WEATHER OR HEAT RELATED PRODUCTS AT
THIS TIME. HAVE REFRESHED THE SPECIAL WEATHER STATEMENT TO KEEP
THE MESSAGE GOING FOR OVERALL CHANGE IN THE WEATHER...TO HOTTER
INLAND TEMPS.
ECMWF SOLUTION PINCHES OFF A 500 MB CIRCULATION JUST OFF THE
COAST BY SUNDAY. THIS WILL LIKELY INDUCE SOME SORT OF COASTAL COOLING
TREND IN THE FORM OF MARINE CLOUDS OR A SOUTHERLY WIND REVERSAL.
850 MB TEMPS WILL STAY AROUND 22 CELSIUS THROUGH SUNDAY AFTERNOON
SO ANY INLAND COOLING WILL BE MINOR AT BEST THROUGH THE WEEKEND.
BY MONDAY HEIGHTS WILL DROP...ONSHORE FLOW WILL INCREASE AND 850
MB TEMPS WILL NUDGE DOWNWARD AS WELL WHICH SHOULD LEAD TO A MARKED
INLAND COOLING TREND AS WELL.
FORECAST FOR NEXT WEEKS SHOWS A WEAK CIRCULATION OFF THE COAST
WHICH SHOULD KEEP A WELL DEFINED AND FAIRLY DEEP MARINE LAYER IN
PLACE. ANY CONVECTION WILL LIKELY STAY OVER THE SIERRA EVEN THOUGH
THE GFS WANTS TO SPIT SOME OUT CLOSER TO THE CENTER OF THE LOW. AS
THE CALENDAR TURNS TO JUNE A FORECAST NEAR CLIMATOLOGICAL NORMS
LOOKS PRETTY GOOD.
&&
.AVIATION...AS OF 4:45 AM PDT THURSDAY...MAINLY VFR CONDITIONS
OVER THE TERMINALS THROUGH THE FORECAST AS HIGH PRESSURE BEGINS TO
BUILD OVER THE REGION. PATCHES OF STRATUS FORMED OVER THE MONTEREY
BAY AND SAN MATEO COAST OVERNIGHT...AND ARE LIKELY TO EXPAND
THROUGH SUNRISE...MAINLY IMPACTING THE MONTEREY BAY TERMINALS.
OTHERWISE...MODERATE ONSHORE FLOW THIS AFTERNOON WITH PATCHY
STRATUS AGAIN FRIDAY MORNING.
VICINITY OF KSFO...VFR CONDITIONS THROUGH THE FORECAST.
STRENGTHENING NORTHERLY GRADIENTS WILL LIKELY KEEP STRATUS OUT OF
THE SF BAY TERMINALS. THERE IS A CHANCE THAT PATCHY STRATUS WILL
IMPACT KOAK THROUGH 17Z. MODERATE WEST WINDS TO 25 KT THIS
AFTERNOON THROUGH THE EARLY EVENING HOURS.
KSFO BRIDGE APPROACH...OCCASIONAL PATCHES OF STRATUS MAY DRIFT
OVER THE APPROACH THROUGH 17Z. LOW CONFIDENCE.
MONTEREY BAY AREA TERMINALS...IFR CIGS THROUGH 17Z. LOW
CONFIDENCE. MOST OF THE SHORT TERM MODELS INITIALIZED POORLY...WITH
ONLY THE LOCAL WRF AND HRRR INDICATING STRATUS MAY DEVELOP
OVERNIGHT. BOTH OF THESE MODELS ARE CONSISTENT IN THE FACT THAT
STRATUS WILL DISSIPATE BY 17Z. OTHERWISE...MODERATE WESTERLY WINDS
THIS AFTERNOON.
&&
.CLIMATE DATA FOR JUNE 1ST...
LOCATION FORECAST NORMAL RECORD TEMPERATURE
SANTA ROSA 92 77 95 1919
SAN RAFAEL 88 73 101 1960
NAPA 91 79 105 1960
SAN FRANCISCO 73 65 90 1989
OAKLAND 80 70 87 1989
LIVERMORE 98 80 105 1938
SANTA CRUZ 85 73 93 1912
SALINAS AIR 78 69 85 1935
.MTR WATCHES/WARNINGS/ADVISORIES...
.TDAY...SCA...PT ARENA TO PT REYES 0-10 NM
SCA...PIGEON PT TO PT PINOS 0-10 NM
SCA...PT PINOS TO PT PIEDRAS BLANCAS 0-10 NM
SCA...PT ARENA TO PIGEON PT 10-60 NM
SCA...PIGEON PT TO PT PIEDRAS BLANCAS 10-60 NM
SCA...PT REYES TO PIGEON PT 0-10 NM
SCA...SF BAY FROM 2 PM
SCA...MRY BAY FROM 2 PM
&&
$$
PUBLIC FORECAST: RWW
AVIATION/MARINE: RILEY
CLIMATE: HENDERSON/LARRY
VISIT US AT WWW.WEATHER.GOV/SANFRANCISCO
FOLLOW US ON FACEBOOK, TWITTER, AND YOUTUBE AT:
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WWW.TWITTER.COM/NWSBAYAREA
WWW.YOUTUBE.COM/NWSBAYAREA
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
1255 PM EDT THU MAY 30 2013
.SYNOPSIS...
HIGH PRESSURE WILL LINGER ACROSS THE CENTRAL ATLANTIC INTO THIS
WEEKEND, BRINGING INCREASING HEAT AND HUMIDITY TO THE MID ATLANTIC
STATES. EARLY NEXT WEEK, A LOW PRESSURE SYSTEM EMERGING FROM THE
GREAT LAKES WILL SEND A COLD FRONT THROUGH OUR REGION BY MONDAY.
HIGH PRESSURE SPREADING SOUTH FROM CENTRAL CANADA IS THEN EXPECTED
TO BUILD TOWARD OUR REGION THROUGH MID WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
NO SIGNIFICANT CHANGES WILL BE MADE WITH THE NEXT ESTF. LOOKS LIKE
THERE IS A BIT OF A SHORT WAVE ON THE WATER VAPOR IMAGERY AND CU
WEST OF US LOOK A BIT MORE ROBUST THAN THEY WERE AT THIS TIME YESTERDAY.
BASED ON THE 12Z SOUNDINGS, WE NUDGED MAX TEMPS EVER SO SLIGHTLY
HIGHER AND PROGRESSED THEM UPWARD A BIT FASTER. MAX HEAT INDICES
ARE IN THE LOWER 90S. TEMPERATURES NEAR THE WATER SHOULD BE
SEVERAL DEGREES COOLER THAN INLAND.
LATEST MESOSCALE MODELS RUN CONTINUE TO SUPPORT THE THINKING OF
ISOLATED OR SLIGHT CHANCE CONVECTION LATER TODAY NORTHWEST. 12Z
SOUNDINGS SHOW IAD AND APG AS CAPPED, BUT CAPPING NOT AS STRONG AT
SITES FARTHER TO THE NORTH AND CONVECTIVE TEMP EXPECTED TO BE
REACHED.
ON POPS, THE MID LEVEL RIDGE DOES BUILD TODAY OVER OUR AREA, AND A
RELATIVELY DRY SOUNDING DOES RESULT IN A RATHER HIGH LFC. HOWEVER,
WE THINK WE END UP WITH SOME CAPE AND NOT A LOT OF CIN DURING THE
AFTERNOON EVEN AFTER ADJUSTING FOR LOWER DEW POINTS. ALSO, THERE
SEEMS TO BE SOME WEAK ENERGY MOVING ALONG THE SKIRT OF THE RIDGE
THAT IS WEAKLY APPARENT ON WATER VAPOR IMAGERY AND THAT COULD WORK
WITH THE INSTABILITY TO TRIGGER CONVECTION. SPC HAS ALMOST THE
ENTIRE AREA UNDER A GENERAL RISK OF CONVECTION TODAY; WE JUST PUT
SLIGHT CHANCE POPS BACK INTO THE AREA NORTHWEST OF THE FALL LINE.
ON WINDS, WE SHOULD SEE A SOUTHWEST TO WEST WIND THAT PEAKS A BIT
ABOVE 10 MPH TODAY. THE H925 WINDS ARE IN OPPOSITION TO ANY SEA/BAY
BREEZE AND FORECAST TO BE AROUND 15 KT. THAT IS RIGHT ON THE EDGE OF
STOPPING IT FROM MAKING MUCH PROGRESS INLAND. SINCE THE LAND/WATER
TEMPERATURE DISCONTINUITY IS GOING TO BE CONSIDERABLE, WE DID
FORECAST IT TO MAKE A LITTLE MORE PROGRESS INLAND THAN WE MIGHT HAVE
LATER IN THE WARM SEASON. WE AREN`T FORECASTING ANY CONVECTION WITH
THE SEA BREEZE AT THIS POINT.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM FRIDAY/...
WHATEVER ENERGY IS AVAILABLE TO TRIGGER ANYTHING SHOULD BE GONE BY
DUSK, AND WE CARRY A DRY THURSDAY NIGHT. THE WINDS MAY DIE OFF A BIT
MORE QUICKLY THAN THEY DID EARLY THIS MORNING, AND SO WE ALLOW FOR A
BIT MORE RADIATING AND LEAN MODESTLY TOWARD COOLER GUIDANCE. WE
DON`T CARRY ANY FOG OR HAZE IN THIS FORECAST.
&&
.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
FOR THE FIRST PART OF THE LONG TERM PERIOD, OUR REGION WILL BE IN
THE MIDST OF THE FIRST HEAT WAVE OF THE SEASON AS SURFACE HIGH
PRESSURE WILL BE FOUND TO OUR EAST ACROSS THE CENTRAL ATLANTIC, WITH
STRONG MID-LEVEL RIDGING ALOFT. THIS WILL PROMOTE AN INCREASING
SOUTHWESTERLY FLOW THROUGH THE MID ATLANTIC REGION, WITH 850MB AND
925MB MODEL TEMPERATURE DATA SUPPORTING MAXIMUM TEMPERATURES ACROSS
THE FORECAST AREA REACHING THE LOWER 90S FRIDAY AND FOR MUCH OF THE
AREA AGAIN ON SATURDAY. DEWPOINTS THROUGH THIS TIME FRAME WILL
MAINLY BE IN THE LOWER TO PERHAPS MIDDLE 60S, YIELDING HEAT INDEX
VALUES IN THE LOWER 90S EACH AFTERNOON. WE WILL CONTINUE A MENTION
IN OUR HAZARDOUS WEATHER OUTLOOK HIGHLIGHTING THIS MULTI-DAY HOT AND
SOMEWHAT MUGGY AIRMASS.
GOING INTO SUNDAY, THIS OVERALL PATTERN WILL BEGIN TO BREAK DOWN, AS
SURFACE HIGH PRESSURE WILL DRIFT FARTHER EAST INTO THE CENTRAL
ATLANTIC AND THE MID-LEVEL RIDGE WILL ALSO BEGIN TO PUSH OFFSHORE.
MEANWHILE, AN AREA OF LOW PRESSURE WILL BE EMERGING FROM AROUND THE
GREAT LAKES SUNDAY AND TRACKING INTO SOUTHEASTERN CANADA THROUGH
MONDAY, ALLOWING A TRAILING COLD FRONT TO APPROACH OUR REGION FROM
THE NORTHWEST. THERE LOOKS TO BE AMPLE INSTABILITY AND LOW LEVEL
MOISTURE IN PLACE AHEAD OF THE APPROACHING FRONTAL BOUNDARY FOR
POTENTIALLY STRONG CONVECTIVE ACTIVITY, AND WE STEADILY INCREASE
POPS FROM NORTHWEST TO SOUTHEAST THROUGH THE COURSE OF SUNDAY INTO
SUNDAY NIGHT. MODEL DIFFERENCES STILL EXIST BETWEEN THE ECMWF, GFS,
AND OTHERS REGARDING THE TIMING OF THE FRONTAL PASSAGE THROUGH THE
REGION MONDAY, AND WITH THIS UNCERTAINTY IN MIND, WE HAVE KEPT HIGH
CHANCE TO LIKELY POPS IN PLACE FOR THE BETTER PART OF MONDAY ACROSS
THE FORECAST AREA FOR SCATTERED SHWR/T-STORM ACTIVITY. FOLLOWING THE
FRONTAL PASSAGE, THERE IS FAIRLY GOOD MODEL AGREEMENT AS AN AREA OF
HIGH PRESSURE FROM CENTRAL CANADA IS PROGGED TO SPREAD SOUTH AND
EAST FROM THE LATTER PART OF MONDAY THROUGH THE MID-WEEK PERIOD.
THIS WILL BRING A NOTICEABLE CHANGE IN AIRMASS TO OUR REGION, WITH
MAXIMUM TEMPERATURES RETURNING TO MORE SEASONAL LEVELS.
&&
.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.
18Z TAFS WILL HAVE VFR CONDITIONS FORECAST THROUGH THE EVENING FOR
ALL TERMINALS AND VFR CONDITIONS ON FRIDAY.
FOR THIS AFTERNOON, NO CIGS ARE FORECAST. SOME HIGH BASED (5K TO
6K) SCATTERED CUMULUS CLOUDS ARE EXPECTED WITH WEST TO SOUTHWEST
WINDS AROUND 10 KTS. WE ARE BRINGING A SEA BREEZE FRONT TO KACY AT
21Z AND A BAY BREEZE FRONT TO KILG AT 22Z. BECAUSE OF THE WINDS
ABOVE THE BOUNDARY LAYER BEING WEST, WE ARE NOT EXPECTING THE SEA
BREEZE FRONT TO MAKE MUCH HEADWAY BEYOND THE IMMEDIATE COASTAL
COUNTIES.
ISOLATED THUNDERSTORMS ARE EXPECTED NORTHWEST OF THE TERMINALS
THIS AFTERNOON AND EARLY EVENING, BUT OVERALL COVERAGE AND
CONFIDENCE THAT THEY WILL MAKE IT TO THE TERMINALS IS TOO LOW TO
INCLUDE. LOWEST CONFIDENCE AT KABE AND KRDG.
FOR THIS EVENING, ANY CUMULUS CLOUDS AROUND SHOULD DISSIPATE
RAPIDLY AND JUST SOME CIRRUS IS EXPECTED. WINDS SHOULD BECOME
LIGHTER FROM THE SOUTHWEST AND LIGHT AND VARIABLE AT SOME OF THE
OUTLYING TERMINALS AND AIRPORTS. THIS SHOULD CONTINUE OVERNIGHT.
ALSO OVERNIGHT WE ARE FORECASTING SOME MVFR CONDITIONS LATE AT
KABE AND KRDG. CONFIDENCE SHOULD BE VIEWED AS AVERAGE.
ANOTHER VFR DAY ON FRIDAY. WE ARE EXPECTING EVEN LESS CUMULUS
BASED COVERAGE AND SLIGHTLY STRONGER WINDS WITH THE DIRECTION
SLIGHTLY MORE TOWARD THE SOUTH. WIND SPEEDS IN THE LAST FORECAST
GROUP ARE MORE REPRESENTATIVE OF THE LATE MORNING AND AFTERNOON
EXPECTATIONS.
OUTLOOK...
FRIDAY NIGHT AND SATURDAY...MAINLY VFR CONDITIONS WITH
SOUTHWESTERLY WINDS. SOME LOCAL REDUCED VSBYS POSSIBLE IN MORNING
HAZE.
SUNDAY AND MONDAY...MOSTLY VFR, EXCEPT TIMES OF POSSIBLE IFR/MVFR IN
SCATTERED SHWRS/T-STORMS, ESPECIALLY FROM SUNDAY AFTN THROUGH MONDAY
MORNING.
&&
.MARINE...
A MARINE LAYER SHOULD BE FAIRLY STRONG TODAY. WINDS ABOVE THE
SURFACE ARE NOT FORECAST TO BE THAT ROBUST, SO WE ARE FORECASTING A
SOUTHWEST WIND THAT IS NOTICEABLE BUT BELOW THE ADVISORY CRITERION.
A SEA/BAY BREEZE MAY MAKE MODEST PROGRESS OUT FROM THE COASTLINE AND
UP THE BAY, AND WINDS THERE MAY COME AROUND TO SOUTH. GIVEN THE
LATER HRRR WE WERE SLIGHTLY MORE AGGRESSIVE BRINGING A BAY BREEZE
UP THE DELAWARE.
SEAS WERE RUNNING AROUND 3 FT OVER THE ATLANTIC WATERS EARLY THIS
MORNING. AS THE PREVIOUS FORECASTER NOTED, WAVE WATCH GUIDANCE IS
VERIFYING TOO HIGH WITH SWELLS. WE CARRY SUB-ADVISORY SEAS THROUGH
THE TONIGHT.
OUTLOOK...
SUB-SCA CONDITIONS EXPECTED FOR OUR WATERS THROUGH FRIDAY AND MOST
OF SATURDAY AS AN AREA OF HIGH PRESSURE LINGERS ACROSS THE CENTRAL
ATLANTIC. BY SATURDAY NIGHT AND INTO SUNDAY, HIGH PRESSURE WILL BE
DRIFTING FARTHER EAST AND AWAY FROM THE REGION, WITH A COLD FRONT
APPROACHING THE AREA FROM THE NORTHWEST DURING SUNDAY. WE ANTICIPATE
WIND GUSTS AND SEAS TO REACH SMALL CRAFT ADVISORY LEVELS DURING THIS
TIME FRAME, AND THESE CONDITIONS WILL MOST LIKELY LAST INTO MONDAY,
AS WELL. SCATTERED SHWRS AND T-STORMS WILL ALSO REDUCE VISIBILITIES
FROM LATE SUNDAY THROUGH MONDAY FOR OUR WATERS, AS THE FRONT
APPROACHES AND TRACKS THROUGH THE REGION.
&&
.RIP CURRENTS...
WE CARRY A LOW PROBABILITY OF RIP CURRENTS TODAY.
RIP CURRENT AWARENESS WEEK IS JUNE 2 THROUGH 8.
PSA`S WILL AIR ON KPHI NWR AND POST DAILY AROUND 545 AM. THERE
WILL BE A SHORT AWARENESS PRESS CONFERENCE IN SURF CITY, LBI ON
TUE JUNE 4 AT 2 PM FOR THOSE MEDIA REPRESENTATIVES WHO ARE
INTERESTED IN RAISING RIP CURRENT AWARENESS AND IN CONDITIONS
FAVORING LIFE THREATENING DANGER IN THE UNGUARDED OCEAN SURF ZONE.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...KLINE
NEAR TERM...DELISI/GIGI
SHORT TERM...DELISI
LONG TERM...KLINE
AVIATION...GIGI/KLINE
MARINE...DELISI/KLINE
RIP CURRENTS...
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
1209 PM EDT THU MAY 30 2013
.SYNOPSIS...
HIGH PRESSURE WILL LINGER ACROSS THE CENTRAL ATLANTIC INTO THIS
WEEKEND, BRINGING INCREASING HEAT AND HUMIDITY TO THE MID ATLANTIC
STATES. EARLY NEXT WEEK, A LOW PRESSURE SYSTEM EMERGING FROM THE
GREAT LAKES WILL SEND A COLD FRONT THROUGH OUR REGION BY MONDAY.
HIGH PRESSURE SPREADING SOUTH FROM CENTRAL CANADA IS THEN EXPECTED
TO BUILD TOWARD OUR REGION THROUGH MID WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
NO SIGNIFICANT CHANGES WILL BE MADE WITH THE NEXT ESTF. LOOKS LIKE
THERE IS A BIT OF A SHORT WAVE ON THE WATER VAPOR IMAGERY AND CU
WEST OF US LOOK A BIT MORE ROBUST THAN THEY WERE AT THIS TIME YESTERDAY.
BASED ON THE 12Z SOUNDINGS, WE NUDGED MAX TEMPS EVER SO SLIGHTLY
HIGHER AND PROGRESSED THEM UPWARD A BIT FASTER. MAX HEAT INDICES
ARE IN THE LOWER 90S. TEMPERATURES NEAR THE WATER SHOULD BE
SEVERAL DEGREES COOLER THAN INLAND.
LATEST MESOSCALE MODELS RUN CONTINUE TO SUPPORT THE THINKING OF
ISOLATED OR SLIGHT CHANCE CONVECTION LATER TODAY NORTHWEST. 12Z
SOUNDINGS SHOW IAD AND APG AS CAPPED, BUT CAPPING NOT AS STRONG AT
SITES FARTHER TO THE NORTH AND CONVECTIVE TEMP EXPECTED TO BE
REACHED.
ON POPS, THE MID LEVEL RIDGE DOES BUILD TODAY OVER OUR AREA, AND A
RELATIVELY DRY SOUNDING DOES RESULT IN A RATHER HIGH LFC. HOWEVER,
WE THINK WE END UP WITH SOME CAPE AND NOT A LOT OF CIN DURING THE
AFTERNOON EVEN AFTER ADJUSTING FOR LOWER DEW POINTS. ALSO, THERE
SEEMS TO BE SOME WEAK ENERGY MOVING ALONG THE SKIRT OF THE RIDGE
THAT IS WEAKLY APPARENT ON WATER VAPOR IMAGERY AND THAT COULD WORK
WITH THE INSTABILITY TO TRIGGER CONVECTION. SPC HAS ALMOST THE
ENTIRE AREA UNDER A GENERAL RISK OF CONVECTION TODAY; WE JUST PUT
SLIGHT CHANCE POPS BACK INTO THE AREA NORTHWEST OF THE FALL LINE.
ON WINDS, WE SHOULD SEE A SOUTHWEST TO WEST WIND THAT PEAKS A BIT
ABOVE 10 MPH TODAY. THE H925 WINDS ARE IN OPPOSITION TO ANY SEA/BAY
BREEZE AND FORECAST TO BE AROUND 15 KT. THAT IS RIGHT ON THE EDGE OF
STOPPING IT FROM MAKING MUCH PROGRESS INLAND. SINCE THE LAND/WATER
TEMPERATURE DISCONTINUITY IS GOING TO BE CONSIDERABLE, WE DID
FORECAST IT TO MAKE A LITTLE MORE PROGRESS INLAND THAN WE MIGHT HAVE
LATER IN THE WARM SEASON. WE AREN`T FORECASTING ANY CONVECTION WITH
THE SEA BREEZE AT THIS POINT.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM FRIDAY/...
WHATEVER ENERGY IS AVAILABLE TO TRIGGER ANYTHING SHOULD BE GONE BY
DUSK, AND WE CARRY A DRY THURSDAY NIGHT. THE WINDS MAY DIE OFF A BIT
MORE QUICKLY THAN THEY DID EARLY THIS MORNING, AND SO WE ALLOW FOR A
BIT MORE RADIATING AND LEAN MODESTLY TOWARD COOLER GUIDANCE. WE
DON`T CARRY ANY FOG OR HAZE IN THIS FORECAST.
&&
.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
FOR THE FIRST PART OF THE LONG TERM PERIOD, OUR REGION WILL BE IN
THE MIDST OF THE FIRST HEAT WAVE OF THE SEASON AS SURFACE HIGH
PRESSURE WILL BE FOUND TO OUR EAST ACROSS THE CENTRAL ATLANTIC, WITH
STRONG MID-LEVEL RIDGING ALOFT. THIS WILL PROMOTE AN INCREASING
SOUTHWESTERLY FLOW THROUGH THE MID ATLANTIC REGION, WITH 850MB AND
925MB MODEL TEMPERATURE DATA SUPPORTING MAXIMUM TEMPERATURES ACROSS
THE FORECAST AREA REACHING THE LOWER 90S FRIDAY AND FOR MUCH OF THE
AREA AGAIN ON SATURDAY. DEWPOINTS THROUGH THIS TIME FRAME WILL
MAINLY BE IN THE LOWER TO PERHAPS MIDDLE 60S, YIELDING HEAT INDEX
VALUES IN THE LOWER 90S EACH AFTERNOON. WE WILL CONTINUE A MENTION
IN OUR HAZARDOUS WEATHER OUTLOOK HIGHLIGHTING THIS MULTI-DAY HOT AND
SOMEWHAT MUGGY AIRMASS.
GOING INTO SUNDAY, THIS OVERALL PATTERN WILL BEGIN TO BREAK DOWN, AS
SURFACE HIGH PRESSURE WILL DRIFT FARTHER EAST INTO THE CENTRAL
ATLANTIC AND THE MID-LEVEL RIDGE WILL ALSO BEGIN TO PUSH OFFSHORE.
MEANWHILE, AN AREA OF LOW PRESSURE WILL BE EMERGING FROM AROUND THE
GREAT LAKES SUNDAY AND TRACKING INTO SOUTHEASTERN CANADA THROUGH
MONDAY, ALLOWING A TRAILING COLD FRONT TO APPROACH OUR REGION FROM
THE NORTHWEST. THERE LOOKS TO BE AMPLE INSTABILITY AND LOW LEVEL
MOISTURE IN PLACE AHEAD OF THE APPROACHING FRONTAL BOUNDARY FOR
POTENTIALLY STRONG CONVECTIVE ACTIVITY, AND WE STEADILY INCREASE
POPS FROM NORTHWEST TO SOUTHEAST THROUGH THE COURSE OF SUNDAY INTO
SUNDAY NIGHT. MODEL DIFFERENCES STILL EXIST BETWEEN THE ECMWF, GFS,
AND OTHERS REGARDING THE TIMING OF THE FRONTAL PASSAGE THROUGH THE
REGION MONDAY, AND WITH THIS UNCERTAINTY IN MIND, WE HAVE KEPT HIGH
CHANCE TO LIKELY POPS IN PLACE FOR THE BETTER PART OF MONDAY ACROSS
THE FORECAST AREA FOR SCATTERED SHWR/T-STORM ACTIVITY. FOLLOWING THE
FRONTAL PASSAGE, THERE IS FAIRLY GOOD MODEL AGREEMENT AS AN AREA OF
HIGH PRESSURE FROM CENTRAL CANADA IS PROGGED TO SPREAD SOUTH AND
EAST FROM THE LATTER PART OF MONDAY THROUGH THE MID-WEEK PERIOD.
THIS WILL BRING A NOTICEABLE CHANGE IN AIRMASS TO OUR REGION, WITH
MAXIMUM TEMPERATURES RETURNING TO MORE SEASONAL LEVELS.
&&
.AVIATION /16Z THURSDAY THROUGH MONDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.
WE AREN`T FORECASTING ANY CEILINGS THROUGH THE TAF PERIOD. SOME VFR
CUMULUS IS FORECAST FOR TODAY. WE CAN`T RULE CONVECTION OUT
COMPLETELY, BUT THE PROBABILITY OF IT AS OF THIS WRITING IS TOO LOW
TO CARRY IN THE TAFS.
WINDS ARE FORECAST TO BE FROM THE SOUTHWEST TO WEST AND PICK UP TO
AROUND OR A BIT ABOVE 10 KT AFTER DAYBREAK. WHETHER A SEA/BAY BREEZE
MAKES IT TO ACY, MIV AND ILG IS UNCERTAIN. GIVEN THE EXPECTED STRONG
TEMPERATURE DIFFERENCE BETWEEN THE WATER AND INLAND AND THE WINDS
ABOVE THE SURFACE, WE FORECAST A BRIEF PERIOD LATE THIS AFTERNOON
AND EARLY THIS EVENING WHEN WINDS AT ACY AND ILG COME AROUND TO
SOUTH. CONFIDENCE IN THAT IS MODERATE AT BEST.
OUTLOOK...
FRIDAY AND SATURDAY...MAINLY VFR CONDITIONS WITH SOUTHWESTERLY
WINDS. SOME LOCAL REDUCED VSBYS POSSIBLE EACH MORNING IN HAZE.
SUNDAY AND MONDAY...MOSTLY VFR, EXCEPT TIMES OF POSSIBLE IFR/MVFR IN
SCATTERED SHWRS/T-STORMS, ESPECIALLY FROM SUNDAY AFTN THROUGH MONDAY
MORNING.
&&
.MARINE...
A MARINE LAYER SHOULD BE FAIRLY STRONG TODAY. WINDS ABOVE THE
SURFACE ARE NOT FORECAST TO BE THAT ROBUST, SO WE ARE FORECASTING A
SOUTHWEST WIND THAT IS NOTICEABLE BUT BELOW THE ADVISORY CRITERION.
A SEA/BAY BREEZE MAY MAKE MODEST PROGRESS OUT FROM THE COASTLINE AND
UP THE BAY, AND WINDS THERE MAY COME AROUND TO SOUTH. GIVEN THE
LATER HRRR WE WERE SLIGHTLY MORE AGGRESSIVE BRINGING A BAY BREEZE
UP THE DELAWARE.
SEAS WERE RUNNING AROUND 3 FT OVER THE ATLANTIC WATERS EARLY THIS
MORNING. AS THE PREVIOUS FORECASTER NOTED, WAVE WATCH GUIDANCE IS
VERIFYING TOO HIGH WITH SWELLS. WE CARRY SUB-ADVISORY SEAS THROUGH
THE TONIGHT.
OUTLOOK...
SUB-SCA CONDITIONS EXPECTED FOR OUR WATERS THROUGH FRIDAY AND MOST
OF SATURDAY AS AN AREA OF HIGH PRESSURE LINGERS ACROSS THE CENTRAL
ATLANTIC. BY SATURDAY NIGHT AND INTO SUNDAY, HIGH PRESSURE WILL BE
DRIFTING FARTHER EAST AND AWAY FROM THE REGION, WITH A COLD FRONT
APPROACHING THE AREA FROM THE NORTHWEST DURING SUNDAY. WE ANTICIPATE
WIND GUSTS AND SEAS TO REACH SMALL CRAFT ADVISORY LEVELS DURING THIS
TIME FRAME, AND THESE CONDITIONS WILL MOST LIKELY LAST INTO MONDAY,
AS WELL. SCATTERED SHWRS AND T-STORMS WILL ALSO REDUCE VISIBILITIES
FROM LATE SUNDAY THROUGH MONDAY FOR OUR WATERS, AS THE FRONT
APPROACHES AND TRACKS THROUGH THE REGION.
&&
.RIP CURRENTS...
WE CARRY A LOW PROBABILITY OF RIP CURRENTS TODAY.
RIP CURRENT AWARENESS WEEK IS JUNE 2 THROUGH 8.
PSA`S WILL AIR ON KPHI NWR AND POST DAILY AROUND 545 AM. THERE
WILL BE A SHORT AWARENESS PRESS CONFERENCE IN SURF CITY, LBI ON
TUE JUNE 4 AT 2 PM FOR THOSE MEDIA REPRESENTATIVES WHO ARE
INTERESTED IN RAISING RIP CURRENT AWARENESS AND IN CONDITIONS
FAVORING LIFE THREATENING DANGER IN THE UNGUARDED OCEAN SURF ZONE.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...KLINE
NEAR TERM...DELISI/GIGI
SHORT TERM...DELISI
LONG TERM...KLINE
AVIATION...DELISI/KLINE
MARINE...DELISI/KLINE
RIP CURRENTS...GIGI
AREA FORECAST DISCUSSION
NWS TAMPA BAY RUSKIN FL
845 PM EDT FRI MAY 31 2013
.UPDATE (TONIGHT AND SATURDAY)...
00Z WATER VAPOR AND H4 RAP ANALYSIS SHOWS AN AMPLIFIED NORTHERN
STREAM ACROSS THE CONUS HIGHLIGHTED BY A DEEP AND VIGOROUS UPPER
TROUGH ACROSS THE CENTRAL PLAINS/UPPER MS VALLEY FOLLOWED DOWNSTREAM
BY LONGWAVE RIDGING OVER THE ATLANTIC SEABOARD. UPPER LEVEL PATTERN
OVER THE FL PENINSULA IS RATHER ILL-DEFINED THIS EVENING...LEANING
TOWARD A SLIGHTLY RIDGED ENVIRONMENT. SOME DRIER MID/UPPER LEVEL AIR
CAN BE SEEN ON WV IMAGERY SPREADING OVER THE NORTHERN PENINSULA
WHILE DEEPER MOISTURE STREAMS NORTH FROM THE YUCATAN ACROSS THE
SOUTHERN HALF OF THE AREA.
AT THE SURFACE...FORECAST AREA RESIDES WITHIN AN EASTERLY FLOW
REGIME AROUND THE SOUTHERN PERIPHERY OF THE SUBTROPICAL RIDGE WHICH
HAS AN AXIS OFF THE GA/CA COASTS THIS EVENING. MUCH OF THE LEFTOVER
SHOWER ACTIVITY THIS EVENING HAS BEEN CONCENTRATED NEAR THE WEST
COAST OF FLORIDA TO THE SOUTH OF TAMPA BAY WHERE THE EASTERLY FLOW
AND DEEPER MOISTURE ARE COINCIDENT.
SCATTERED SHOWERS ARE LIKELY TO CONTINUE TO THE SOUTH OF TAMPA BAY
FOR THE NEXT FEW HOURS...AND THEN SLOWLY FADE FOR THE MAJORITY OF
THE OVERNIGHT PERIOD.
LOW LEVEL GRADIENT LOOKS TO BREAK DOWN A LITTLE FOR SATURDAY WHICH
SHOULD ALLOW A MORE TYPICAL SUMMER-LIKE PATTERN TO DEVELOP FOR TH
REGION. THE WEAKER GRADIENT WILL ALLOW A MORE PRONOUNCED SEA-BREEZE
CIRCULATION TO DEVELOP AND THIS CIRCULATION ALONG WITH SOME WEAK
SYNOPTIC EASTERLY FLOW SHOULD SET THE STAGE FOR AN ACTIVE
AFTERNOON/EVENING OF SHOWERS AND STORMS ALONG THE WEST COAST OF THE
PENINSULA. NOT ANTICIPATING A WASHOUT...AND THE FIRST HALF OF THE
DAY IS LIKELY TO BE MAINLY DRY...WARM...AND MUGGY. HOWEVER...KEEP AN
EYE TO THE SKY FOR ANY AFTERNOON OUTDOOR ACTIVITIES...AS MANY ARE
LIKELY TO BE DODGING A STORM OR TWO.
&&
.AVIATION...
GUSTY WINDS AND VCNTY SHRA IN THE SOUTH BOTH END THIS EVENING.
GENERALLY VFR OVERNIGHT ALTHOUGH EXPECT SOME MVFR CIGS LAL/PGD LATE
NIGHT. LATE MORNING SHRA/EARLY AFTERNOON TSRA INCREASE WITH POSSIBLE
MVFR/IFR CONDITIONS LATE AFTERNOON ESPECIALLY AT COASTAL TERMINALS.
EASTERLY WINDS IN THE MORNING SHIFT TO ONSHORE NEAR THE GULF IN THE
AFTERNOON.
&&
.MARINE...
EASTERLY FLOW WILL INCREASE TO NEAR EXERCISE CAUTION LEVELS DURING
THE OVERNIGHT...ESPECIALLY FROM ENGLEWOOD NORTHWARD...WITH SEAS
BUILDING TO BETWEEN 3 AND 4 FEET AWAY FROM SHORE. THE GRADIENT IS
THEN EXPECTED TO RELAX SOMEWHAT OVER THE EASTERN GULF OF MEXICO
AFTER SATURDAY MORNING. THIS RELAX GRADIENT WILL LEAD TO MORE
TYPICAL SUMMER-LIKE CONDITIONS DOMINATED BY AFTERNOON AND EVENING
SEA BREEZES. THE PATTERN IS FAVORABLE FOR AFTERNOON AND EVENING
THUNDERSTORMS TO REMAIN CLOSE TO THE COAST SATURDAY AFTERNOON SO
KEEP AND EYE TO THE SKY IF BOATING IN THE NEARSHORE WATERS.
&&
.FIRE WEATHER...
NO CONCERNS.
&&
.PRELIMINARY POINT TEMPS/POPS...
TPA 73 89 74 88 / 20 60 40 60
FMY 72 90 74 90 / 30 60 30 60
GIF 72 91 72 91 / 10 50 30 50
SRQ 72 88 73 88 / 30 60 40 60
BKV 71 91 70 90 / 10 60 40 60
SPG 76 90 76 88 / 20 60 40 60
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GULF WATERS...NONE.
&&
$$
UPDATE/MARINE...MROCZKA
AVIATION...RUDE
AREA FORECAST DISCUSSION
NWS MIAMI FL
1036 AM EDT THU MAY 30 2013
.UPDATE...
THE FLOOD WATCH THAT WAS IN EFFECT FOR THE EASTERN HALF OF
SOUTH FLORIDA HAS BEEN CANCELLED. WHILE THE 12Z SOUNDING HAD A
PWAT NEAR TWO INCHES...THE OVERALL SYNOPTIC CONDITIONS ARE NOT
COMPLETELY FAVORABLE FOR WIDESPREAD CONVECTION ACROSS THE EASTERN
HALF OF SOUTH FLORIDA AND THE AREAL COVERAGE OF POTENTIALLY HEAVY
RAINFALL IS EXPECTED TO BE LESS. HOWEVER...LOCALLY HEAVY RAINFALL
IS STILL POSSIBLE ACROSS SOUTH FLORIDA TODAY BUT OVER ISOLATED
AREAS. TWO SYNOPTIC FACTORS THAT HAVE REDUCED THE CHANCES OF
CONVECTION OVER A MORE WIDESPREAD AREA INCLUDE THE POSITION OF THE
UPPER LEVEL TROUGH AND THE MID LEVEL LAPSE RATE/TEMPERATURE. THE
UPPER LEVEL TROUGH ACROSS THE SOUTHEASTERN U.S. IS ORIENTATED SUCH
THAT A WEAK RIDGE HAS BUILT ACROSS THE REGION AND THE 12Z SOUNDING
INDICATED 500 HPA TEMPERATURES THAT ARE REPRESENTATIVE OF
CLIMATOLOGY FOR THIS DATE. PLUS THE LAPSE RATES ABOVE 500 HPA ARE WEAK.
FOR THESE REASONS WIDESPREAD CONVECTION ACROSS THE EASTERN HALF OF
SOUTH FLORIDA IS LESS LIKELY AND THE FLOOD WATCH HAS BEEN
CANCELLED. HOWEVER...ABUNDANT LOW LEVEL MOISTURE CONTINUES ACROSS
THE REGION AND SOME DRIER MID TO UPPER LEVEL IS PRESENT. FOR THE
AFTERNOON AND EARLY EVENING...DAY TIME HEATING SHOULD RESULT IN
CONVECTION WITH ISOLATED THUNDERSTORMS POSSIBLE AND A SLIGHT
CHANCE OF SMALL HAIL. AND NEED TO RE-EMPHASIZE THAT LOCALLY HEAVY
RAINFALL WILL BE POSSIBLE IN ISOLATED AREAS.
REGIONAL OBSERVATIONS ACROSS THE LOCAL ATLANTIC WATERS INDICATE
STRONG WINDS IN THE 20 TO 24 KNOT RANGE POSSIBLE WITH A SMALL
CRAFT ADVISORY CONTINUING ACROSS THE ATLANTIC WATERS...INCLUDING
BISCAYNE BAY. A SMALL CRAFT ADVISORY FOR THE GULF WATERS CONTINUES
TO BE IN EFFECT THROUGH 00Z THIS EVENING BUT LATEST GUIDANCE
INDICATES THAT WINDS SHOULD SLOWLY SUBSIDE THROUGH THE DAY AND THAT
ADVISORY MAY BE CANCELLED WITH THE AFTERNOON ISSUANCE OF THE
COASTAL WATERS FORECAST.
60
&&
.PREV DISCUSSION... /ISSUED 700 AM EDT THU MAY 30 2013/
AVIATION...
BERMUDA HIGH CONTINUES TO BRING STRONG EASTERLY FLOW AND RAIN
SHOWERS TO SOUTH FLORIDA THROUGH THE TAF PERIOD. THE RAIN MAY BE
HEAVY AT TIMES, REDUCING FLIGHT CATEGORIES TO MVFR AND IFR FOR
SHORT PERIODS OF TIME. HOWEVER, WITH SUCH GREAT UNCERTAINTY AS TO
WHEN AND WHERE THIS WILL OCCUR, HAVE NOT REFLECTED THE REDUCTIONS
IN THE TAFS AT THIS TIME. WINDS WILL BE GUSTY ONCE AGAIN TODAY,
WITH SOME WEAKENING SOME TONIGHT.
PREV DISCUSSION... /ISSUED 238 AM EDT THU MAY 30 2013/
SHORT TERM (TODAY THROUGH SATURDAY)...
THE GLOBAL MODELS CONTINUE TO STRUGGLE WITH THE OVERALL SURFACE
SYNOPTIC PATTERN IN THIS PERIOD BUT ARE IN AGREEMENT THAT THE MID
LEVEL PRESSURE PATTERN WILL REMAIN QUITE WEEK ACROSS SOUTH
FLORIDA. THE GFS, ECMWF AND NAM ALL SHOW A WEAK 500 MB TROUGH
DEVELOPING EAST OF THE PENINSULA ON FRIDAY AND SATURDAY DRIFTING
IT TO THE NORTHEAST. THIS COULD ALLOW FOR SOME SLIGHT DRYING ALOFT
AS DRIER AIR MOVES SOUTHWARD ON THE WEST SIDE OF THE TROUGH. THIS
IS REFLECTED IN THE LATEST POP GUIDANCE FROM BOTH THE MET AND MAV
WHICH SHOW A TREND WITH LOWER NUMBERS AFTER TODAY. THE NAM AND GFS
HAVE COME MORE IN LINE AT THE SURFACE IN DEVELOPING A WEAK
INVERTED TROUGH OVER THE FLORIDA STRAITS ON FRIDAY AND DRIFTING IT
TO THE NORTH ON SATURDAY WHICH LESSENS THE LOW LEVEL SOUTHEAST
WIND FLOW SIGNIFICANTLY. THE ECMWF DOES NOT SHOW THIS FEATURE
MAINTAINING AN ONSHORE FLOW ALONG THE SOUTHEAST COAST ALTHOUGH IN
A WEAKENED STATE AS IT SHOWS THE RIDGE TO THE NORTH WEAKENING. THE
NAM HAS INITIALIZED THE BEST COMPARING IT TO CURRENT OBSERVATIONS
FROM THE C-MAN STATIONS BUT THE QUESTION WILL THE WEAK TROUGH
DEVELOP AS FORECAST FROM THE NAM AND GFS. EVEN THOUGH THE NAM AND
GFS HAVE BEEN CONSISTENT IN FORECASTING THIS TROUGH, THEY HAVE
BEEN VERY INCONSISTENT IN ITS TIMING. THEREFORE, WILL LEAN TOWARDS
THE NAM EARLY IN THE PERIOD BUT THEN GO MORE WITH THE ECMWF FOR
FRIDAY NIGHT AND SATURDAY.
THE OTHER FACTOR IN THE SHORT TERM IS THE AMOUNT OF RAINFALL THAT
IS POSSIBLE. MOST OF THE RAIN THE PAST FEW DAYS HAS BEEN
CONCENTRATED OVER THE EASTERN HALF OF THE SOUTHERN PENINSULA WITH
VERY SATURATED GROUNDS FROM PERSISTENT RAIN PERIODS SINCE APRIL.
GIVEN THE ONGOING ONSHORE FLOW OF MOIST AND UNSTABLE AIR AND
SCATTERED SHOWERS, THE FLOOD WATCH WILL CONTINUE THROUGH 12Z
FRIDAY. THE LATEST RUN OF THE HRRR WHICH TYPICALLY DOES QUITE WELL
DOES NOT SHOW MUCH ACTIVITY THROUGH EARLY THURSDAY. HOWEVER, WITH
VERY LITTLE CHANGE IN THIS PATTERN AT LEAST THROUGH THURSDAY NIGHT
THE SHOWER ACTIVITY COULD DEVELOP AT ANY TIME AND MOVE ONSHORE
WITHIN THE FLOOD WATCH BOX.
LONG TERM (SATURDAY NIGHT THROUGH WEDNESDAY)...
BOTH THE GFS AND ECMWF ARE IN GOOD AGREEMENT SHOWING A MID LEVEL
TROUGH DEEPENING ACROSS THE EASTERN U.S. MAINTAINING A RIDGE TO
THE WEST AND A WEAK PRESSURE PATTERN ACROSS SOUTH FLORIDA. AT THE
SURFACE, BOTH MODELS COME MORE IN LINE WITH A LIGHTER SOUTHEAST
FLOW AS THE RIDGE WEAKENS AND SHIFTS TO THE EAST AS A WEAK COLD
FRONT MOVES INTO THE SOUTHEAST STATES. HOWEVER, THE GFS THEN
DEVELOPS A STRONGER SURFACE TROUGH OVER THE GULF STATES LATE IN
THE PERIOD AND VEERS THE WIND ACROSS SOUTH FLORIDA TO THE
SOUTHWEST. BEING THIS LATE IN THE FORECAST, WILL NOT JUMP ON THAT
AND WILL LEAN MORE TOWARDS THE ECMWF SOLUTION THROUGH THE ENTIRE
EXTENDED PERIOD.
MARINE...
ROUGH MARINE CONDITIONS WILL CONTINUE THROUGH AT LEAST EARLY
FRIDAY. MODEL GUIDANCE HINTS AT SOME WEAKENING IN THE GRADIENT
FLOW LATE FRIDAY INTO THE WEEKEND WITH CALMER WIND AND SEAS. JUST
HOW MUCH WEAKENING DEPENDS ON THE RAPIDNESS OF THE SLACKENING
GRADIENT WITH TIME. FOR NOW, HAVE KEPT A SOUTHEAST FLOW WITH
SUBSIDING SPEEDS AS HIGH PRESSURE RETREATS TO THE EAST.
FIRE WEATHER...
NO PROBLEMS OR CONCERNS WITH AMPLE TROPICAL MOISTURE IN PLACE.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 84 77 86 76 / 60 30 50 40
FORT LAUDERDALE 83 76 85 77 / 60 40 50 40
MIAMI 83 75 87 76 / 60 40 50 40
NAPLES 89 72 89 74 / 60 30 40 30
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...RIP CURRENT RISK THROUGH FRIDAY AFTERNOON FOR COASTAL BROWARD-
COASTAL MIAMI DADE-COASTAL PALM BEACH.
AM...SMALL CRAFT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR BISCAYNE
BAY-COASTAL WATERS FROM DEERFIELD BEACH TO OCEAN REEF, FL
OUT 20 NM-COASTAL WATERS FROM JUPITER INLET TO DEERFIELD
BEACH, FL OUT 20 NM-WATERS FROM DEERFIELD BEACH TO OCEAN
REEF, FL EXTENDING FROM 20 NM TO THE TERRITORIAL WATERS OF
THE BAHAMAS-WATERS FROM JUPITER INLET TO DEERFIELD BEACH,
FL EXTENDING FROM 20 NM TO 60 NM.
GM...SMALL CRAFT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR COASTAL
WATERS FROM CHOKOLOSKEE TO BONITA BEACH, FL OUT 20 NM-
COASTAL WATERS FROM EAST CAPE SABLE TO CHOKOLOSKEE, FL OUT
20 NM-GULF WATERS FROM CHOKOLOSKEE TO BONITA BEACH, FL
EXTENDING FROM 20 TO 60 NM.
&&
$$
DISCUSSION/MARINE/FIRE...60/BD
AVIATION/RADAR...10/CD
AREA FORECAST DISCUSSION
NWS MIAMI FL
700 AM EDT THU MAY 30 2013
.AVIATION...
BERMUDA HIGH CONTINUES TO BRING STRONG EASTERLY FLOW AND RAIN
SHOWERS TO SOUTH FLORIDA THROUGH THE TAF PERIOD. THE RAIN MAY BE
HEAVY AT TIMES, REDUCING FLIGHT CATEGORIES TO MVFR AND IFR FOR
SHORT PERIODS OF TIME. HOWEVER, WITH SUCH GREAT UNCERTAINTY AS TO
WHEN AND WHERE THIS WILL OCCUR, HAVE NOT REFLECTED THE REDUCTIONS
IN THE TAFS AT THIS TIME. WINDS WILL BE GUSTY ONCE AGAIN TODAY,
WITH SOME WEAKENING SOME TONIGHT.
&&
.PREV DISCUSSION... /ISSUED 238 AM EDT THU MAY 30 2013/
SHORT TERM (TODAY THROUGH SATURDAY)...
THE GLOBAL MODELS CONTINUE TO STRUGGLE WITH THE OVERALL SURFACE
SYNOPTIC PATTERN IN THIS PERIOD BUT ARE IN AGREEMENT THAT THE MID
LEVEL PRESSURE PATTERN WILL REMAIN QUITE WEEK ACROSS SOUTH
FLORIDA. THE GFS, ECMWF AND NAM ALL SHOW A WEAK 500 MB TROUGH
DEVELOPING EAST OF THE PENINSULA ON FRIDAY AND SATURDAY DRIFTING
IT TO THE NORTHEAST. THIS COULD ALLOW FOR SOME SLIGHT DRYING ALOFT
AS DRIER AIR MOVES SOUTHWARD ON THE WEST SIDE OF THE TROUGH. THIS
IS REFLECTED IN THE LATEST POP GUIDANCE FROM BOTH THE MET AND MAV
WHICH SHOW A TREND WITH LOWER NUMBERS AFTER TODAY. THE NAM AND GFS
HAVE COME MORE IN LINE AT THE SURFACE IN DEVELOPING A WEAK
INVERTED TROUGH OVER THE FLORIDA STRAITS ON FRIDAY AND DRIFTING IT
TO THE NORTH ON SATURDAY WHICH LESSENS THE LOW LEVEL SOUTHEAST
WIND FLOW SIGNIFICANTLY. THE ECMWF DOES NOT SHOW THIS FEATURE
MAINTAINING AN ONSHORE FLOW ALONG THE SOUTHEAST COAST ALTHOUGH IN
A WEAKENED STATE AS IT SHOWS THE RIDGE TO THE NORTH WEAKENING. THE
NAM HAS INITIALIZED THE BEST COMPARING IT TO CURRENT OBSERVATIONS
FROM THE C-MAN STATIONS BUT THE QUESTION WILL THE WEAK TROUGH
DEVELOP AS FORECAST FROM THE NAM AND GFS. EVEN THOUGH THE NAM AND
GFS HAVE BEEN CONSISTENT IN FORECASTING THIS TROUGH, THEY HAVE
BEEN VERY INCONSISTENT IN ITS TIMING. THEREFORE, WILL LEAN TOWARDS
THE NAM EARLY IN THE PERIOD BUT THEN GO MORE WITH THE ECMWF FOR
FRIDAY NIGHT AND SATURDAY.
THE OTHER FACTOR IN THE SHORT TERM IS THE AMOUNT OF RAINFALL THAT
IS POSSIBLE. MOST OF THE RAIN THE PAST FEW DAYS HAS BEEN
CONCENTRATED OVER THE EASTERN HALF OF THE SOUTHERN PENINSULA WITH
VERY SATURATED GROUNDS FROM PERSISTENT RAIN PERIODS SINCE APRIL.
GIVEN THE ONGOING ONSHORE FLOW OF MOIST AND UNSTABLE AIR AND
SCATTERED SHOWERS, THE FLOOD WATCH WILL CONTINUE THROUGH 12Z
FRIDAY. THE LATEST RUN OF THE HRRR WHICH TYPICALLY DOES QUITE WELL
DOES NOT SHOW MUCH ACTIVITY THROUGH EARLY THURSDAY. HOWEVER, WITH
VERY LITTLE CHANGE IN THIS PATTERN AT LEAST THROUGH THURSDAY NIGHT
THE SHOWER ACTIVITY COULD DEVELOP AT ANY TIME AND MOVE ONSHORE
WITHIN THE FLOOD WATCH BOX.
LONG TERM (SATURDAY NIGHT THROUGH WEDNESDAY)...
BOTH THE GFS AND ECMWF ARE IN GOOD AGREEMENT SHOWING A MID LEVEL
TROUGH DEEPENING ACROSS THE EASTERN U.S. MAINTAINING A RIDGE TO
THE WEST AND A WEAK PRESSURE PATTERN ACROSS SOUTH FLORIDA. AT THE
SURFACE, BOTH MODELS COME MORE IN LINE WITH A LIGHTER SOUTHEAST
FLOW AS THE RIDGE WEAKENS AND SHIFTS TO THE EAST AS A WEAK COLD
FRONT MOVES INTO THE SOUTHEAST STATES. HOWEVER, THE GFS THEN
DEVELOPS A STRONGER SURFACE TROUGH OVER THE GULF STATES LATE IN
THE PERIOD AND VEERS THE WIND ACROSS SOUTH FLORIDA TO THE
SOUTHWEST. BEING THIS LATE IN THE FORECAST, WILL NOT JUMP ON THAT
AND WILL LEAN MORE TOWARDS THE ECMWF SOLUTION THROUGH THE ENTIRE
EXTENDED PERIOD.
MARINE...
ROUGH MARINE CONDITIONS WILL CONTINUE THROUGH AT LEAST EARLY
FRIDAY. MODEL GUIDANCE HINTS AT SOME WEAKENING IN THE GRADIENT
FLOW LATE FRIDAY INTO THE WEEKEND WITH CALMER WIND AND SEAS. JUST
HOW MUCH WEAKENING DEPENDS ON THE RAPIDNESS OF THE SLACKENING
GRADIENT WITH TIME. FOR NOW, HAVE KEPT A SOUTHEAST FLOW WITH
SUBSIDING SPEEDS AS HIGH PRESSURE RETREATS TO THE EAST.
FIRE WEATHER...
NO PROBLEMS OR CONCERNS WITH AMPLE TROPICAL MOISTURE IN PLACE.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 84 77 86 76 / 60 30 50 40
FORT LAUDERDALE 83 76 85 77 / 70 40 50 40
MIAMI 83 75 87 76 / 70 40 50 40
NAPLES 89 72 89 74 / 60 30 40 30
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...FLOOD WATCH THROUGH FRIDAY MORNING FOR COASTAL BROWARD-COASTAL
MIAMI DADE-COASTAL PALM BEACH-FAR SOUTH MIAMI DADE-INLAND
BROWARD-INLAND MIAMI DADE-INLAND PALM BEACH-METRO BROWARD-
METRO MIAMI DADE-METRO PALM BEACH.
RIP CURRENT RISK THROUGH FRIDAY AFTERNOON FOR COASTAL BROWARD-
COASTAL MIAMI DADE-COASTAL PALM BEACH.
AM...SMALL CRAFT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR BISCAYNE
BAY-COASTAL WATERS FROM DEERFIELD BEACH TO OCEAN REEF, FL
OUT 20 NM-COASTAL WATERS FROM JUPITER INLET TO DEERFIELD
BEACH, FL OUT 20 NM-WATERS FROM DEERFIELD BEACH TO OCEAN
REEF, FL EXTENDING FROM 20 NM TO THE TERRITORIAL WATERS OF
THE BAHAMAS-WATERS FROM JUPITER INLET TO DEERFIELD BEACH,
FL EXTENDING FROM 20 NM TO 60 NM.
GM...SMALL CRAFT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR COASTAL
WATERS FROM CHOKOLOSKEE TO BONITA BEACH, FL OUT 20 NM-
COASTAL WATERS FROM EAST CAPE SABLE TO CHOKOLOSKEE, FL OUT
20 NM-GULF WATERS FROM CHOKOLOSKEE TO BONITA BEACH, FL
EXTENDING FROM 20 TO 60 NM.
&&
$$
DISCUSSION/MARINE/FIRE...30/KOB
AVIATION/RADAR...13/SI
AREA FORECAST DISCUSSION
NWS TALLAHASSEE FL
320 AM EDT Thu May 30 2013
.NEAR TERM [Through Tonight]...
At upper levels, we see a negatively tilted trough over the central
part of the nation and a ridge over much of the Southeast. Surface
analysis continues to show a ridge axis extending from off the
Carolina coast westward to East Texas. We have seen a very gradual
moistening of the lower levels over the past few days with some
isolated to scattered showers and thunderstorms finally developing
along the inland moving sea breeze on Wednesday. We believe we will
see similar development today. PoPs will be based on a blend of sea
breeze climatology for a type 7 day (strong southeast flow) and
local confidence and CAM guidance. We have continued the recent
trend of going a degree or two above a guidance blend for max temps,
and even more than that for the VLD area. Winds should stay up
enough to once again preclude any fog formation, although if any
place was to see it, it would be the Tallahassee metro area. Min
temps will be 2-4 degrees above normal, generally ranging from the
upper 60s north to the lower 70s for the coastal zones.
&&
.SHORT TERM [Friday Through Saturday]...
We are still only expecting generally subtle changes to both the
Upper level and Lower level patterns over the course of the short
term period, with weak ridging continuing aloft, with the surface
high pressure system lingering to the east of the Carolinas.
However, with the southeasterly flow persisting (albeit gradually
weakening at the lower levels) deep layer moisture is expected to
continue to increase. Precipitable water values in the forecast
soundings may exceed 1.75 inches in many areas by the end of the day
on Saturday, which should allow the Sea Breeze Front to become more
efficient at producing mainly afternoon and evening showers and
thunderstorms over the interior, and the nighttime Land Breeze to
produce more convection over the Coastal Waters. Therefore, went
above all available guidance for PoPs on both days (save the always
extremely high SREF), with inland rain chances ranging from 20 to 40
percent on Friday, and 40 to 50 percent on Saturday. Despite the
increase in PoPs, high and low temps are expected to remain a bit
above climo, with highs ranging from the mid 80s along the coast to
the lower 90s further inland. Low temps will range from the upper
60s, to the lower 70s from the interior to the coast.
&&
.LONG TERM [Saturday Night through Tuesday]...
The large scale longwave pattern commences with ridging over Wrn,
troughing over Cntrl to Appalachians/Wrn Gulf ridging Ewd into Wrn
Atlc. At the surface, high Wrn Atlc with ridge Ewd across Nrn gulf
region. Low over Nrn Great Lakes with cold front SSW across TN
Valley into TX.
During the rest of the period, Cntrl trough will continue pushing
Ewd with axis down Ern Gulf Sun night or Mon with ECMWF quickest in
movement. Cold front pushed SEWD with weakening and retreating ridge
but with again some model disagreement. Some models like GFS
stall it along Nrn gulf coast others like ECMWF bring it across
our area Mon into Mon night with veering winds and an increase in
rain Sun into Mon. As trough/front push offshore, upstream ridge
begins to overspread region Tues. Also by Monday, both the GFS and
ECMWF develop a surface wave near the Yucatan Peninsula with some
indication that this low will develop NEWD into the Gulf of Mex.
but it is far too early to determine the track or intensity of
this possible feature. Seasonable temperatures should occur
throughout the period, with highs generally in the low 90s and
lows in the mid- upper 60s.
&&
.AVIATION
[Through 06 UTC Friday] The NARRE and HRRR guidance once again
support the gridded LAMP and MOS in showing low ceilings developing
overnight across most of the area. We show a few hours of MVFR at
the terminals, not quite as low as guidance, but similar to what
happened yesterday. Visibility restrictions are not anticipated as
surface winds are forecast to remain around 5-9 kt through the
night. One possible exception is the TLH vicinity which received the
bulk of the showers and storms last evening. We indicate some
restriction there, but not below the ceiling category. Isolated to
scattered shower and thunderstorm development is expected once again
this afternoon. However, coverage is not expected to be sufficient
for tempo groups and convection was only mentioned in the vicinity
of area terminals.
&&
.MARINE...
A ridge of high pressure to the east of the Carolinas will continue
to provide favorable conditions for mainly nocturnal wind surges
out of the southeast through Saturday. Winds speeds will continue to
reach the Cautionary range, with a few areas near Small Craft
Advisory levels through tonight and into Friday morning. The
pressure pattern is expected to weaken and break down by later on
Saturday and very clearly by Sunday, with afternoon wind speeds
around 10 knots anticipated by Sunday afternoon.
&&
.FIRE WEATHER...
RH will be insufficiently low to reach red flag criteria for the
foreseeable future. However, dispersion indices will remain
elevated, over 75 across most areas today and again on Friday.
&&
.HYDROLOGY...
Isolated to scattered showers and thunderstorms are expected over
the next several days, and though a few locations could receive
locally heavy rainfall, no significant impacts are anticipated on
our area rivers.
&&
.PRELIMINARY POINT TEMPS/POPS...
Tallahassee 91 70 91 69 91 / 40 10 30 20 50
Panama City 88 73 87 73 87 / 30 20 30 20 50
Dothan 92 68 91 69 92 / 30 20 30 20 40
Albany 91 68 92 67 92 / 10 10 30 20 40
Valdosta 93 67 93 67 92 / 20 10 20 20 40
Cross City 93 67 92 67 92 / 30 20 30 20 50
Apalachicola 87 72 85 73 85 / 30 20 30 20 40
&&
.TAE WATCHES/WARNINGS/ADVISORIES...
FL...None.
GA...None.
AL...None.
GM...None.
&&
$$
NEAR TERM...Wool
SHORT TERM...Gould
LONG TERM...Block
AVIATION...Wool
MARINE...Gould
FIRE WEATHER...Wool
HYDROLOGY...Gould
AREA FORECAST DISCUSSION
NWS MIAMI FL
238 AM EDT THU MAY 30 2013
.SHORT TERM (TODAY THROUGH SATURDAY)...
THE GLOBAL MODELS CONTINUE TO STRUGGLE WITH THE OVERALL SURFACE
SYNOPTIC PATTERN IN THIS PERIOD BUT ARE IN AGREEMENT THAT THE MID
LEVEL PRESSURE PATTERN WILL REMAIN QUITE WEEK ACROSS SOUTH
FLORIDA. THE GFS, ECMWF AND NAM ALL SHOW A WEAK 500 MB TROUGH
DEVELOPING EAST OF THE PENINSULA ON FRIDAY AND SATURDAY DRIFTING
IT TO THE NORTHEAST. THIS COULD ALLOW FOR SOME SLIGHT DRYING ALOFT
AS DRIER AIR MOVES SOUTHWARD ON THE WEST SIDE OF THE TROUGH. THIS
IS REFLECTED IN THE LATEST POP GUIDANCE FROM BOTH THE MET AND MAV
WHICH SHOW A TREND WITH LOWER NUMBERS AFTER TODAY. THE NAM AND GFS
HAVE COME MORE IN LINE AT THE SURFACE IN DEVELOPING A WEAK
INVERTED TROUGH OVER THE FLORIDA STRAITS ON FRIDAY AND DRIFTING IT
TO THE NORTH ON SATURDAY WHICH LESSENS THE LOW LEVEL SOUTHEAST
WIND FLOW SIGNIFICANTLY. THE ECMWF DOES NOT SHOW THIS FEATURE
MAINTAINING AN ONSHORE FLOW ALONG THE SOUTHEAST COAST ALTHOUGH IN
A WEAKENED STATE AS IT SHOWS THE RIDGE TO THE NORTH WEAKENING. THE
NAM HAS INITIALIZED THE BEST COMPARING IT TO CURRENT OBSERVATIONS
FROM THE C-MAN STATIONS BUT THE QUESTION WILL THE WEAK TROUGH
DEVELOP AS FORECAST FROM THE NAM AND GFS. EVEN THOUGH THE NAM AND
GFS HAVE BEEN CONSISTENT IN FORECASTING THIS TROUGH, THEY HAVE
BEEN VERY INCONSISTENT IN ITS TIMING. THEREFORE, WILL LEAN TOWARDS
THE NAM EARLY IN THE PERIOD BUT THEN GO MORE WITH THE ECMWF FOR
FRIDAY NIGHT AND SATURDAY.
THE OTHER FACTOR IN THE SHORT TERM IS THE AMOUNT OF RAINFALL THAT
IS POSSIBLE. MOST OF THE RAIN THE PAST FEW DAYS HAS BEEN
CONCENTRATED OVER THE EASTERN HALF OF THE SOUTHERN PENINSULA WITH
VERY SATURATED GROUNDS FROM PERSISTENT RAIN PERIODS SINCE APRIL.
GIVEN THE ONGOING ONSHORE FLOW OF MOIST AND UNSTABLE AIR AND
SCATTERED SHOWERS, THE FLOOD WATCH WILL CONTINUE THROUGH 12Z
FRIDAY. THE LATEST RUN OF THE HRRR WHICH TYPICALLY DOES QUITE WELL
DOES NOT SHOW MUCH ACTIVITY THROUGH EARLY THURSDAY. HOWEVER, WITH
VERY LITTLE CHANGE IN THIS PATTERN AT LEAST THROUGH THURSDAY NIGHT
THE SHOWER ACTIVITY COULD DEVELOP AT ANY TIME AND MOVE ONSHORE
WITHIN THE FLOOD WATCH BOX.
.LONG TERM (SATURDAY NIGHT THROUGH WEDNESDAY)...
BOTH THE GFS AND ECMWF ARE IN GOOD AGREEMENT SHOWING A MID LEVEL
TROUGH DEEPENING ACROSS THE EASTERN U.S. MAINTAINING A RIDGE TO
THE WEST AND A WEAK PRESSURE PATTERN ACROSS SOUTH FLORIDA. AT THE
SURFACE, BOTH MODELS COME MORE IN LINE WITH A LIGHTER SOUTHEAST
FLOW AS THE RIDGE WEAKENS AND SHIFTS TO THE EAST AS A WEAK COLD
FRONT MOVES INTO THE SOUTHEAST STATES. HOWEVER, THE GFS THEN
DEVELOPS A STRONGER SURFACE TROUGH OVER THE GULF STATES LATE IN
THE PERIOD AND VEERS THE WIND ACROSS SOUTH FLORIDA TO THE
SOUTHWEST. BEING THIS LATE IN THE FORECAST, WILL NOT JUMP ON THAT
AND WILL LEAN MORE TOWARDS THE ECMWF SOLUTION THROUGH THE ENTIRE
EXTENDED PERIOD.
&&
.AVIATION...
BERMUDA HIGH CONTINUES TO BRING STRONG EASTERLY FLOW AND RAIN
SHOWERS TO SOUTH FLORIDA THROUGH THE TAF PERIOD. THERE IS A LULL
IN PRECIPITATION THIS MORNING THAT SHOULD COME TO AN END AFTER
SUNRISE. THE RAIN MAY BE HEAVY AT TIMES, REDUCING FLIGHT
CATEGORIES TO MVFR AND IFR FOR SHORT PERIODS OF TIME. HOWEVER,
WITH SUCH GREAT UNCERTAINTY AS TO WHEN AND WHERE THEY WILL OCCUR,
HAVE NOT REFLECTED THE REDUCTIONS IN THE TAFS AT THIS TIME. WINDS
WILL BE GUSTY ONCE AGAIN TODAY. THERE IS SOME INDICATION IN THE
MODELS THAT WINDS AND PRECIPITATION MAY SETTLE DOWN FOR AT LEAST
WHILE LATE THIS EVENING AND POSSIBLY OVERNIGHT TONIGHT. BUT,
CONFIDENCE IS LOW ON THIS AT THIS TIME.
&&
.MARINE...
ROUGH MARINE CONDITIONS WILL CONTINUE THROUGH AT LEAST EARLY
FRIDAY. MODEL GUIDANCE HINTS AT SOME WEAKENING IN THE GRADIENT
FLOW LATE FRIDAY INTO THE WEEKEND WITH CALMER WIND AND SEAS. JUST
HOW MUCH WEAKENING DEPENDS ON THE RAPIDNESS OF THE SLACKENING
GRADIENT WITH TIME. FOR NOW, HAVE KEPT A SOUTHEAST FLOW WITH
SUBSIDING SPEEDS AS HIGH PRESSURE RETREATS TO THE EAST.
&&
.FIRE WEATHER...
NO PROBLEMS OR CONCERNS WITH AMPLE TROPICAL MOISTURE IN PLACE.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 84 77 86 76 / 60 30 50 40
FORT LAUDERDALE 83 76 85 77 / 70 40 50 40
MIAMI 83 75 87 76 / 70 40 50 40
NAPLES 89 72 89 74 / 60 30 40 30
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...FLOOD WATCH THROUGH FRIDAY MORNING FOR COASTAL BROWARD-COASTAL
MIAMI DADE-COASTAL PALM BEACH-FAR SOUTH MIAMI DADE-INLAND
BROWARD-INLAND MIAMI DADE-INLAND PALM BEACH-METRO BROWARD-
METRO MIAMI DADE-METRO PALM BEACH.
RIP CURRENT RISK THROUGH FRIDAY AFTERNOON FOR COASTAL BROWARD-
COASTAL MIAMI DADE-COASTAL PALM BEACH.
AM...SMALL CRAFT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR BISCAYNE
BAY-COASTAL WATERS FROM DEERFIELD BEACH TO OCEAN REEF, FL
OUT 20 NM-COASTAL WATERS FROM JUPITER INLET TO DEERFIELD
BEACH, FL OUT 20 NM-WATERS FROM DEERFIELD BEACH TO OCEAN
REEF, FL EXTENDING FROM 20 NM TO THE TERRITORIAL WATERS OF
THE BAHAMAS-WATERS FROM JUPITER INLET TO DEERFIELD BEACH,
FL EXTENDING FROM 20 NM TO 60 NM.
GM...SMALL CRAFT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR COASTAL
WATERS FROM CHOKOLOSKEE TO BONITA BEACH, FL OUT 20 NM-
COASTAL WATERS FROM EAST CAPE SABLE TO CHOKOLOSKEE, FL OUT
20 NM-GULF WATERS FROM CHOKOLOSKEE TO BONITA BEACH, FL
EXTENDING FROM 20 TO 60 NM.
&&
$$
DISCUSSION/MARINE/FIRE...30/KOB
AVIATION/RADAR...13/SI
AREA FORECAST DISCUSSION...UPDATED
NWS PEACHTREE CITY GA
132 AM EDT THU MAY 30 2013
.PREV DISCUSSION... /ISSUED 800 PM EDT WED MAY 29 2013/
UPDATE...
NO CHANGES PLANNED FOR THE FORECAST EXCEPT SOME MINOR TWEAKS TO SKY
COVER.
41
PREVIOUS...
SHORT TERM /TONIGHT THROUGH THURSDAY NIGHT/...
CURRENT SATELLITE LOOP SHOWS BKN TO OVC ACROSS THE AREA WITH THE
CLOUDS ROTATING AROUND THE HIGH PRESSURE RIDGE. THE SURFACE AND
UPPER LEVEL RIDGES ARE ALMOST VERTICALLY STACKED WHICH IS DOING A
VERY GOOD JOB OF KEEPING ANY CU DEVELOPMENT FROM BECOMING A
SHOWER/THUNDERSTORM. EVEN WITH THE GOOD MOIST EASTERLY FLOW THIS
RIDGE SHOULD KEEP UP PRECIPITATION FREE THROUGH THE SHORT TERM. A
FEW OF OUR LOCAL MODELS...THE HRRR AND THE LOCAL WRF...ARE TRYING TO
SHOW SOME SHOWERS DEVELOPING THIS AFTERNOON ACROSS OUR SOUTHEASTERN
COUNTIES. BOTH OF THESE MODELS APPEAR TO BE PICKING UP ON WHAT LOOKS
TO BE A SEA BREEZE FRONT AND BRINGS IN SO LIGHT SHOWERS THIS
AFTERNOON. THE RIDGE IS FIRMLY ENTRENCHED ACROSS SE GA SO I WOULD
TEND TO RULE OUT ANY PRECIP TODAY OR THURSDAY. FOR NOW AM KEEPING
ANY PRECIP WORDING OUT WITH POPS REMAINING BELOW 15 PERCENT. WITH
THE MOIST EASTERLY FLOW WE WILL SEE INCREASED CLOUD COVER AGAIN
THURSDAY WITH SOME LOW STRATUS MOVING IN TONIGHT. THESE LOW CLOUDS
WILL KEEP TEMPS UP A LITTLE HIGHER THAN THE PAST COUPLE OF NIGHTS
WITH MAX TEMPS THROUGH THURSDAY STAY IN THE 80S AND 90S.
01
LONG TERM /FRIDAY THROUGH WEDNESDAY/...
MAINLY ONLY TWEAKS TO THE LONG TERM. CAN NOT COMPLETELY RULE OUT
SMALL CHANCES FOR SHOWERS/STORMS FRIDAY AFTERNOON OVER THE WESTERN
CWA AND SATURDAY AFTERNOON FOR MUCH OF N AND CENTRAL GA. SHOWERS AND
STORMS STILL MOST LIKELY SUNDAY AND MONDAY.
BDL
PREVIOUS DISCUSSION...
ECMWF AND GFS IN GOOD AGREEMENT INTO THE WEEKEND WITH DIFFERENCES
DEVELOPING AT THE EARLY PART OF NEXT WEEK. THE H5 RIDGE MAINTAINS
ITS HOLD OVER THE CWA THROUGH FRIDAY...THEN THE RIDGE BEGINS TO
BREAK DOWN AS THE UPPER TROUGH MOVES INTO THE MIDWEST. THIS WILL
DRIVE A COLD FRONT INTO THE TENNESSEE AND OHIO VALLEYS LATE SATURDAY
AND INTO SUNDAY AND MONDAY. THE ECMWF IS A LITTLE FASTER AND BRINGS
MOISTURE WITH THE FRONT INTO THE CWA LATE SATURDAY NIGHT. BOTH
MODELS PROG THE FRONT TO TAP INTO GULF MOISTURE SUNDAY BRINGING A
GOOD CHANCE OF PRECIP TO MUCH OF THE CWA. DIFFERENCES DEVELOP SUNDAY
NIGHT/MONDAY ON THE SPEED OF EXITING THE FRONT AND ASSOCIATED
MOISTURE. THE ECMWF PUSHES THE FRONT THROUGH BUT THE SOUTHEAST
CORNER OF THE CWA BY 12Z MONDAY WHILE THE GFS HOLDS THE FRONT BACK
CLEARING ONLY THE NORTHWEST PART OF THE CWA BY 12Z MON AND THEN
DEVELOPS A SECONDARY UPPER WAVE THAT INCREASES MOISTURE OVER MOST OF
THE CWA DURING THE DAY MONDAY. AT THIS POINT WILL MAINTAIN HIGH POPS
SUNDAY AND MONDAY AND BRING LOW OR NO POPS ON TUESDAY.
17
&&
.AVIATION...
06Z UPDATE...
VFR TO START THE PERIOD...BUT EXPECT LOW MVFR TO POTENTIALLY IFR
CIGS TO MOVE IN OVER THE NEXT FEW HOURS. EXPECT IMPROVEMENT
STARTING BETWEEN 15-17Z...WITH VFR CONDITIONS EXPECTED THROUGH THE
AFTERNOON. EXPECT ANOTHER ROUND OF LOW MVFR TO IFR CONDITIONS
FRIDAY MORNING...AND WITH GUIDANCE MORE PESSIMISTIC FOR TOMORROW
THAN TODAY...HAVE INTRODUCED IFR CIGS FOR ATL AROUND 10Z FRIDAY.
SE WINDS THROUGH THE PERIOD GENERALLY BETWEEN 5-10KT THIS
AFTERNOON...MAY SEE SOME LOW-END GUSTS AS WELL.
//ATL CONFIDENCE...06Z UPDATE...
MEDIUM ON TIMING OF CIGS TODAY AND TOMORROW.
MEDIUM ON CIG HEIGHTS.
HIGH ON ALL OTHER ELEMENTS.
TDP
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 87 66 85 66 / 5 5 10 10
ATLANTA 85 66 85 67 / 5 5 20 10
BLAIRSVILLE 83 63 82 63 / 5 5 10 10
CARTERSVILLE 86 66 85 66 / 5 10 20 10
COLUMBUS 88 68 89 71 / 10 10 30 10
GAINESVILLE 83 66 83 65 / 5 5 10 10
MACON 88 66 88 65 / 5 5 10 10
ROME 87 66 85 66 / 5 20 30 10
PEACHTREE CITY 86 66 85 65 / 5 5 20 10
VIDALIA 90 67 90 70 / 5 5 5 10
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS POCATELLO ID
922 AM MDT THU MAY 30 2013
.UPDATE...NO UPDATES PLANNED FOR TODAY. ELONGATED UPPER TROUGH
LAYING ACROSS THE AREA TODAY. WEAK SHORTWAVE IN PLACE OVER
SOUTHERN IDAHO AND WEAK CONVECTION STILL ONGOING IN PORTIONS OF
EASTERN HIGHLANDS PER RADAR IMAGERY. EASTERN IDAHO WEAKLY
DESTABILIZED THIS AFTERNOON WITH 0 TO -2 LIFTEDS MAINLY NORTH OF
KSUN-KPIH LINE. HRRR CONCURS WITH WEAK CONVECTION NORTH OF THIS
LINE BUT ALSO STRETCHING SLIGHTLY SOUTH THROUGH THE EASTERN
HIGHLANDS TO THE BEAR LAKE AREA...CLOSE TO SECONDARY AREA OF
INSTABILITY OVER NORTHERN UTAH. REST OF THE FORECAST AREA LARGELY
DRY AND STABLE. ONLY OTHER CONCERN WILL BE WINDS ACROSS THE SNAKE
PLAIN. GUIDANCE CONTINUES TO INDICATE ADVISORY LEVEL WINDS THIS
AFTERNOON AT KPIH SO WILL CONTINUE WIND ADVISORY FOR THE ENTIRE
ZONE. EVEN IF WINDS ARE MARGINAL FOR THIS ADVISORY...LAKE WIND
ADVISORY IS CERTAIN SO WILL LEAVE HEADLINE IN PLACE REGARDLESS. DMH
&&
.PREV DISCUSSION... /ISSUED 315 AM MDT THU MAY 30 2013/
DISCUSSION...UPPER LOW IS SITTING OFF IN THE EAST PACIFIC JUST WEST
OF VANCOUVER ISLAND. WV IMAGERY SHOWS A COUPLE OF WEAK IMPULSES OF
ENERGY ROTATING OUT OF THE LOW. MODELS PROJECT LITTLE SENSIBLE
WEATHER ASSOCIATED WITH THESE IMPULSES...AND WEATHER SHOULD BE
RELATIVELY CLEAR ACROSS THE AREA TODAY. AS A RESULT...LOW LEVEL
LAPSE RATES WILL STEEPEN ALLOWING SOME OF THE STRONGER WINDS TO MIX
TO THE SURFACE THIS AFTERNOON. MOS GUIDANCE IS INDICATING STRONGER
WINDS THAN YESTERDAY AND WE WILL LIKELY SEE ADVISORY LEVEL WIND
SPEEDS THIS AFTERNOON ACROSS THE LOWER SNAKE RIVER PLAIN. DRY
WEATHER SHOULD CONTINUE THROUGH SATURDAY AS UPPER RIDGING MOVES
ACROSS THE AREA.
ON SUNDAY...MODELS DEPICT AN AMPLIFYING UPPER TROUGH DEVELOPING OVER
THE PACIFIC NORTHWEST...BUT CONTINUE TO PUSH MOST OF THE MOISTURE
OVER NORTHERN IDAHO AND WESTERN MONTANA. THEREFORE WE SHOULD SEE
LITTLE IN THE WAY OF POPS EARLY NEXT WEEK. THE 00Z GFS/ECMWF DROPS
AN UPPER TROUGH OVER THE UPPER SNAKE HIGHLANDS...WHICH MAY BE THE
ONLY AREA OF CONCERN IN THE EXTENDED PERIODS AS FAR AS POPS ARE
CONCERNED. HINSBERGER
AVIATION...ISOLATED THUNDERSTORMS EXPECTED OVER THE CENTRAL
MOUNTAINS NORTH OF KSUN THIS AFTERNOON AND THE EASTERN HIGHLANDS AS
WELL. TAF SITES SHOULD NOT BE AFFECTED TODAY BY THESE SHOWERS. MAIN
CONCERN WILL BE STRONG SURFACE WINDS IN THE SNAKE PLAIN THIS
AFTERNOON. STRONGEST WINDS WILL BE IN THE VICINITY OF KPIH WHERE A
WIND ADVISORY HAS BEEN ISSUED FOR SOUTHWEST WINDS OF 25 TO 35 MPH
BETWEEN 20Z AND 03Z THIS EVENING. RS/EP
FIRE WEATHER...THE STORM TRACK HAS SHIFTED FURTHER NORTH TODAY.
ISOLATED SHOWERS AND THUNDERSTORMS ARE EXPECTED OVER THE MOUNTAINS
MAINLY NORTH OF A STANLEY TO DRIGGS LINE THIS AFTERNOON. STRONG
GUSTY WINDS WILL REDEVELOP AGAIN THIS AFTERNOON IN THE SNAKE
PLAIN...STRONGEST WINDS WILL BE LOCATED IN THE SOUTHERN HALF OF THE
PLAIN FROM BURLEY TO BLACKFOOT. WEST TO SOUTHWEST WINDS OF 25 TO 35
MPH ARE EXPECTED FROM 1400 TO 2100 HOURS. ON FRIDAY...ISOLATED
SHOWERS WILL BE LIMITED TO AREAS FROM LEADORE TO ISLAND PARK AND
DRIGGS. RELATIVE HUMIDITY WILL LOWER TO AROUND 20 PERCENT AROUND
ARCO FRIDAY AND TREND DOWNWARD TO THE UPPER TEENS BY SATURDAY
AFTERNOON. RS/EP
&&
.PIH WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY FROM 2 PM THIS AFTERNOON TO 9 PM MDT THIS EVENING
IDZ021.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
949 PM CDT FRI MAY 31 2013
.MESOSCALE DISCUSSION...
855 PM CDT
THE MAIN CONCERNS THIS EVENING ARE THE THREATS FOR HEAVY RAIN AND
THE POSSIBILITY OF SOME ADDITIONAL SEVERE WEATHER...MAINLY ACROSS MY
FAR SOUTHERN COUNTIES IN CENTRAL ILLINOIS FROM PONTIAC TO KANKAKEE
TO VALPO INDIANA AND POINTS SOUTH. I AM A BIT CONCERNED WITH THE
THREAT FOR ADDITIONAL SEVERE STORMS ACROSS THIS AREA OVER THE NEXT
COUPLE OF HOURS THIS EVENING. THE 00 UTC SOUNDING OUT OF ILX IS
QUITE IMPRESSIVE...BOTH FOR HEAVY RAINFALL AND FOR SEVERE STORMS.
THE 0-1 KM HELICITY IS 200-250 M2/S2 WITH SOME DECENT VEERING
WITHIN THE LOWEST 100MB. IN ADDITION TO THE STRONG LOW LEVEL
HELICITY...VERY LOW LCL`S AND RESULTANT LOW LEVEL CAPE IS
CERTAINLY CONCERNING REGARDING AT LEAST SOME TORNADO POTENTIAL.
THIS IS THE ENVIRONMENT THAT THE STORMS CURRENTLY MOVING ACROSS
WEST CENTRAL ILLINOIS AND DOWN TOWARDS STL ARE MOVING INTO AND HAS
PROMPTED A TORNADO WATCH JUST SOUTH OF OUR AREA. THIS TORNADIC
SEVERE THREAT WILL NEED TO BE MONITORED TO SEE IF THE THREAT WILL
EXTEND FARTHER NORTH AS DEW POINTS HAVE RECOVERED BACK TO NEAR 70
ACROSS FAR SOUTHERN SECTIONS OF MY AREA IN THE WAKE OF THE EARLIER
CONVECTION.
THE FLASH FLOOD THREAT WILL ALSO CONTINUE TO BE A CONCERN...MAINLY
ACROSS THE FAR SOUTHERN SECTIONS OF THE AREA. THE EARLIER STORMS
PRODUCED UP TO AN INCH AND HALF ACROSS PORTIONS OF LIVINGSTON
THROUGH IROQUOIS COUNTIES IN ILLINOIS AND ALSO ACROSS PORTIONS OF
NORTHWESTERN ILLINOIS. WITH THIS IN MIND IT SHOULD NOT TAKE MUCH TO
EXCEED FLASH FLOOD GUIDANCE ACROSS THESE AREAS. THEREFORE...I WILL
CONTINUE THE FLASH FLOOD WATCH.
KJB
&&
.DISCUSSION...
336 PM CDT
THOUGHTS FROM THE EARLIER MESO DISCUSSION ARE STILL VALID AND HAVE
BEEN BOLSTERED BY THE SPREAD OF SHOWERS WITH ISOLATED TSRA INTO THE
FCST AREA THIS AFTERNOON WITH LITTLE ADDITIONAL DEVELOPMENT DIRECTLY
WEST OVER IOWA SO FAR. 0-6 KM BULK SHEAR CONTINUES TO BE MARGINAL
OVER MOST OF THE LOCAL REGION BUT IS BUILDING TOWARD 40 KTS IN THE
AREA OF APPROACHING CONVECTION TO OUR SOUTHWEST UNDER THE LEADING
EDGE OF AN UPPER LEVEL JET. A FEW STORMS COULD BECOME ORGANIZED IN
SOUTHERN PORTIONS OF THE CWA...THOUGH THE SEVERE RISK OVERALL
APPEARS TO BE MARGINAL. TRENDS FOR THIS EVENING AND OVERNIGHT
ALSO WOULD CONTINUE TO FAVOR SOUTHERN PORTIONS OF THE CWA FOR THE
HEAVIEST RAINFALL AMOUNTS AND THE CORRESPONDING FLOOD RISK...AND
THIS ALSO IS WHERE THE MOST RAIN HAS FALLEN OVER THE PAST WEEK. FOR
THESE REASONS...AFTER COORDINATION WITH NEIGHBORS...WILL PLAN TO
DROP THE FLOOD WATCH FOR NORTHERN PORTIONS OF THE FORECAST AREA.
ALL OF THIS ACTIVITY IS BEING DRIVEN BY RICH BOUNDARY LAYER GULF
MOISTURE WRAPPING AROUND THE WESTERN SIDE OF A BERMUDA HIGH...AND
AHEAD OF AN APPROACHING FRONTAL ZONE TIED TO LOW PRESSURE OVER THE
DAKOTAS. THIS FRONTAL ZONE PUSHES THROUGH THE AREA SATURDAY NIGHT
AND USHERS IN COOLER AND DRIER AIR FOR THE FIRST HALF OF NEXT WEEK.
UNSETTLED WEATHER WILL PERSIST UNTIL THAT TIME WITH THE FOCUS
GRADUALLY SHIFTING EASTWARD. SHOWER AND THUNDERSTORM FORECAST
TRENDS FOR THIS EVENING AND OVERNIGHT ARE BASED ON CURRENT ACTIVITY
AND THE IDEA OF INCREASING DEVELOPMENT SUPPORTED BY LOW LEVEL
MOISTURE CONVERGENCE BEING DEPICTED IN THE RAP MODEL. IF THESE RAP
FIELDS CONTINUE TO BE VALID TOWARD MORNING...THE NORTHWEST HALF OF
THE AREA WOULD APPEAR TO DRY OUT BY MIDNIGHT AND REMAIN SO INTO THE
MORNING HOURS. THIS TREND ALSO IS SUPPORTED BY THE LATEST
NAM/ECMWF/GFS QPF FIELDS. CHANCES THEN INCREASE AGAIN DURING THE
DAY TOMORROW AHEAD OF THE APPROACHING UPPER LEVEL VORT MAX AND THE
SURFACE FRONTAL ZONE.
AFTER A COOLER AND DRIER END TO THE WEEKEND AND START TO THE WORK
WEEK...THE NEXT UPPER TROUGH AND SFC LOW BEGIN TO APPROACH THE
AREA TOWARD THE MIDDLE OF NEXT WEEK ALONG THE SIMILAR DAKOTAS TRACK
THAT WE HAVE SEEN WITH THE CURRENT SYSTEM. SFC WINDS TURNING
SOUTHEAST BY WEDNESDAY AND SOUTH BY THURSDAY WOULD ALLOW WARM MOIST
GULF AIR TO START WORKING BACK INTO THE AREA FOR LATE NEXT
WEEK...BUT AT THIS RANGE WILL ONLY PLAN TO CARRY CHANCE POPS.
LENNING
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 03Z...
* MVFR CIGS THRU LATE EVENING
* ISOLD SHRA UNTIL AROUND OR JUST AFTER MIDNIGHT
* CHANCE OF TSRA SAT AFTERNOON
IZZI
//DISCUSSION...UPDATED 00Z...
POCKETS OF MVFR CIGS BLOSSOMING IN THE VERY MOIST AIR MASS OVER
WESTERN ILLINOIS WITH SOME CONCERN THAT THESE CIGS COULD CONTINUE
TO EXPAND EASTWARD INTO CHGO AREA AFTER SUNSET. WHEN/IF CIGS MOVE
IN CERTAINLY PLAUSIBLE THAT THEY COULD LINGER THROUGH TONIGHT AND
POSSIBLY INTO SATURDAY MORNING. ASSUMING MVFR CIGS DO DEVELOP THEN
THEY WOULD LIKELY LIFT TO VFR DURING THE MORNING SATURDAY.
ADDITIONAL SHOWERS AND THUNDERSTORMS COULD DEVELOP SATURDAY
AFTERNOON AS WE REMAIN REMAIN AHEAD OF THE FRONT AND IN THE
WARM/HUMID AIR MASS. MODELS CONTINUE TO STRUGGLE WITH THE PRECISE
DETAILS OF CONVECTIVE EVOLUTION HOWEVER CURRENT INDICATIONS ARE
THE BETTER THREAT OF THUNDERSTORMS ON SATURDAY MAY END UP BEING
SOUTH OF THE CHICAGO AREA TERMINALS.
IZZI
//ORD AND MDW CONFIDENCE...UPDATED 03Z...
* LOW-MEDIUM CONFIDENCE IN CIGS TONIGHT INTO SATURDAY MORNING
* LOW CONFIDENCE IN TSRA CHANCES SAT AFTERNOON
IZZI
//OUTLOOK FOR ORD/MDW FOR 12Z SUNDAY-12Z FRIDAY...UPDATED 00Z...
SUNDAY THROUGH TUESDAY...VFR.
WEDNESDAY AND THURSDAY...CHANCE OF TSRA.
IZZI
&&
.MARINE...
222 PM CDT
AN AREA OF LOW PRESSURE THAT HAS PERSISTED OVER THE NORTHERN PLAINS
WILL FINALLY BEGIN TO MOVE EAST TONIGHT...PASSING OVER NORTHERN LAKE
MICHIGAN LATE SATURDAY EVENING WITH A TRAILING COLD FRONT TURNING
MODERATE SOUTHERLY WINDS OF 15 TO 25 KT TO NORTHWESTERLY. MOIST FLOW
AHEAD OF THE FRONT HAS ALREADY LED TO DENSE FOG OVER MUCH OF THE
LAKE WHICH IS EXPECTED TO PERSIST UNTIL THE COLD FRONT PASSES
SATURDAY NIGHT. WINDS SHOULD THEN DIMINISH THROUGH THE DAY SUNDAY AS
HIGH PRESSURE BUILDS IN FROM THE WEST...BECOMING CENTERED OVER LAKE
MICHIGAN ON MONDAY. LOW PRESSURE WILL DEVELOP OVER THE CENTRAL
PLAINS MONDAY...THEN LIFT NORTHEAST TO LAKE MICHIGAN LATE THURSDAY
INTO EARLY FRIDAY.
BMD
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...FLASH FLOOD WATCH...ILZ021-ILZ022-ILZ023-ILZ032-ILZ033-ILZ039
UNTIL 7 PM SATURDAY.
IN...FLASH FLOOD WATCH...INZ001-INZ002-INZ010-INZ011-INZ019 UNTIL 7
PM SATURDAY.
LM...DENSE FOG ADVISORY...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ868-LMZ870-
LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 9 PM 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
855 PM CDT FRI MAY 31 2013
.MESOSCALE DISCUSSION...
855 PM CDT
THE MAIN CONCERNS THIS EVENING ARE THE THREATS FOR HEAVY RAIN AND
THE POSSIBILITY OF SOME ADDITIONAL SEVERE WEATHER...MAINLY ACROSS MY
FAR SOUTHERN COUNTIES IN CENTRAL ILLINOIS FROM PONTIAC TO KANKAKEE
TO VALPO INDIANA AND POINTS SOUTH. I AM A BIT CONCERNED WITH THE
THREAT FOR ADDITIONAL SEVERE STORMS ACROSS THIS AREA OVER THE NEXT
COUPLE OF HOURS THIS EVENING. THE 00 UTC SOUNDING OUT OF ILX IS
QUITE IMPRESSIVE...BOTH FOR HEAVY RAINFALL AND FOR SEVERE STORMS.
THE 0-1 KM HELICITY IS 200-250 M2/S2 WITH SOME DECENT VEERING
WITHIN THE LOWEST 100MB. IN ADDITION TO THE STRONG LOW LEVEL
HELICITY...VERY LOW LCL`S AND RESULTANT LOW LEVEL CAPE IS
CERTAINLY CONCERNING REGARDING AT LEAST SOME TORNADO POTENTIAL.
THIS IS THE ENVIRONMENT THAT THE STORMS CURRENTLY MOVING ACROSS
WEST CENTRAL ILLINOIS AND DOWN TOWARDS STL ARE MOVING INTO AND HAS
PROMPTED A TORNADO WATCH JUST SOUTH OF OUR AREA. THIS TORNADIC
SEVERE THREAT WILL NEED TO BE MONITORED TO SEE IF THE THREAT WILL
EXTEND FARTHER NORTH AS DEW POINTS HAVE RECOVERED BACK TO NEAR 70
ACROSS FAR SOUTHERN SECTIONS OF MY AREA IN THE WAKE OF THE EARLIER
CONVECTION.
THE FLASH FLOOD THREAT WILL ALSO CONTINUE TO BE A CONCERN...MAINLY
ACROSS THE FAR SOUTHERN SECTIONS OF THE AREA. THE EARLIER STORMS
PRODUCED UP TO AN INCH AND HALF ACROSS PORTIONS OF LIVINGSTON
THROUGH IROQUOIS COUNTIES IN ILLINOIS AND ALSO ACROSS PORTIONS OF
NORTHWESTERN ILLINOIS. WITH THIS IN MIND IT SHOULD NOT TAKE MUCH TO
EXCEED FLASH FLOOD GUIDANCE ACROSS THESE AREAS. THEREFORE...I WILL
CONTINUE THE FLASH FLOOD WATCH.
KJB
&&
.DISCUSSION...
336 PM CDT
THOUGHTS FROM THE EARLIER MESO DISCUSSION ARE STILL VALID AND HAVE
BEEN BOLSTERED BY THE SPREAD OF SHOWERS WITH ISOLATED TSRA INTO THE
FCST AREA THIS AFTERNOON WITH LITTLE ADDITIONAL DEVELOPMENT DIRECTLY
WEST OVER IOWA SO FAR. 0-6 KM BULK SHEAR CONTINUES TO BE MARGINAL
OVER MOST OF THE LOCAL REGION BUT IS BUILDING TOWARD 40 KTS IN THE
AREA OF APPROACHING CONVECTION TO OUR SOUTHWEST UNDER THE LEADING
EDGE OF AN UPPER LEVEL JET. A FEW STORMS COULD BECOME ORGANIZED IN
SOUTHERN PORTIONS OF THE CWA...THOUGH THE SEVERE RISK OVERALL
APPEARS TO BE MARGINAL. TRENDS FOR THIS EVENING AND OVERNIGHT
ALSO WOULD CONTINUE TO FAVOR SOUTHERN PORTIONS OF THE CWA FOR THE
HEAVIEST RAINFALL AMOUNTS AND THE CORRESPONDING FLOOD RISK...AND
THIS ALSO IS WHERE THE MOST RAIN HAS FALLEN OVER THE PAST WEEK. FOR
THESE REASONS...AFTER COORDINATION WITH NEIGHBORS...WILL PLAN TO
DROP THE FLOOD WATCH FOR NORTHERN PORTIONS OF THE FORECAST AREA.
ALL OF THIS ACTIVITY IS BEING DRIVEN BY RICH BOUNDARY LAYER GULF
MOISTURE WRAPPING AROUND THE WESTERN SIDE OF A BERMUDA HIGH...AND
AHEAD OF AN APPROACHING FRONTAL ZONE TIED TO LOW PRESSURE OVER THE
DAKOTAS. THIS FRONTAL ZONE PUSHES THROUGH THE AREA SATURDAY NIGHT
AND USHERS IN COOLER AND DRIER AIR FOR THE FIRST HALF OF NEXT WEEK.
UNSETTLED WEATHER WILL PERSIST UNTIL THAT TIME WITH THE FOCUS
GRADUALLY SHIFTING EASTWARD. SHOWER AND THUNDERSTORM FORECAST
TRENDS FOR THIS EVENING AND OVERNIGHT ARE BASED ON CURRENT ACTIVITY
AND THE IDEA OF INCREASING DEVELOPMENT SUPPORTED BY LOW LEVEL
MOISTURE CONVERGENCE BEING DEPICTED IN THE RAP MODEL. IF THESE RAP
FIELDS CONTINUE TO BE VALID TOWARD MORNING...THE NORTHWEST HALF OF
THE AREA WOULD APPEAR TO DRY OUT BY MIDNIGHT AND REMAIN SO INTO THE
MORNING HOURS. THIS TREND ALSO IS SUPPORTED BY THE LATEST
NAM/ECMWF/GFS QPF FIELDS. CHANCES THEN INCREASE AGAIN DURING THE
DAY TOMORROW AHEAD OF THE APPROACHING UPPER LEVEL VORT MAX AND THE
SURFACE FRONTAL ZONE.
AFTER A COOLER AND DRIER END TO THE WEEKEND AND START TO THE WORK
WEEK...THE NEXT UPPER TROUGH AND SFC LOW BEGIN TO APPROACH THE
AREA TOWARD THE MIDDLE OF NEXT WEEK ALONG THE SIMILAR DAKOTAS TRACK
THAT WE HAVE SEEN WITH THE CURRENT SYSTEM. SFC WINDS TURNING
SOUTHEAST BY WEDNESDAY AND SOUTH BY THURSDAY WOULD ALLOW WARM MOIST
GULF AIR TO START WORKING BACK INTO THE AREA FOR LATE NEXT
WEEK...BUT AT THIS RANGE WILL ONLY PLAN TO CARRY CHANCE POPS.
LENNING
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 00Z...
* MVFR CIGS POSSIBLE TONIGHT
* CHANCE OF TSRA SAT AFTERNOON
IZZI
//DISCUSSION...UPDATED 00Z...
POCKETS OF MVFR CIGS BLOSSOMING IN THE VERY MOIST AIR MASS OVER
WESTERN ILLINOIS WITH SOME CONCERN THAT THESE CIGS COULD CONTINUE
TO EXPAND EASTWARD INTO CHGO AREA AFTER SUNSET. WHEN/IF CIGS MOVE
IN CERTAINLY PLAUSIBLE THAT THEY COULD LINGER THROUGH TONIGHT AND
POSSIBLY INTO SATURDAY MORNING. ASSUMING MVFR CIGS DO DEVELOP THEN
THEY WOULD LIKELY LIFT TO VFR DURING THE MORNING SATURDAY.
ADDITIONAL SHOWERS AND THUNDERSTORMS COULD DEVELOP SATURDAY
AFTERNOON AS WE REMAIN REMAIN AHEAD OF THE FRONT AND IN THE
WARM/HUMID AIR MASS. MODELS CONTINUE TO STRUGGLE WITH THE PRECISE
DETAILS OF CONVECTIVE EVOLUTION HOWEVER CURRENT INDICATIONS ARE
THE BETTER THREAT OF THUNDERSTORMS ON SATURDAY MAY END UP BEING
SOUTH OF THE CHICAGO AREA TERMINALS.
IZZI
//ORD AND MDW CONFIDENCE...UPDATED 00Z...
* MEDIUM-HIGH CONFIDENCE IN DRY FORECAST THROUGH SATURDAY MORNING
* LOW-MEDIUM CONFIDENCE IN CIGS TONIGHT INTO SATURDAY MORNING
* LOW CONFIDENCE IN TSRA CHANCES SAT AFTERNOON
IZZI
//OUTLOOK FOR ORD/MDW FOR 12Z SUNDAY-12Z FRIDAY...UPDATED 00Z...
SUNDAY THROUGH TUESDAY...VFR.
WEDNESDAY AND THURSDAY...CHANCE OF TSRA.
IZZI
&&
.MARINE...
222 PM CDT
AN AREA OF LOW PRESSURE THAT HAS PERSISTED OVER THE NORTHERN PLAINS
WILL FINALLY BEGIN TO MOVE EAST TONIGHT...PASSING OVER NORTHERN LAKE
MICHIGAN LATE SATURDAY EVENING WITH A TRAILING COLD FRONT TURNING
MODERATE SOUTHERLY WINDS OF 15 TO 25 KT TO NORTHWESTERLY. MOIST FLOW
AHEAD OF THE FRONT HAS ALREADY LED TO DENSE FOG OVER MUCH OF THE
LAKE WHICH IS EXPECTED TO PERSIST UNTIL THE COLD FRONT PASSES
SATURDAY NIGHT. WINDS SHOULD THEN DIMINISH THROUGH THE DAY SUNDAY AS
HIGH PRESSURE BUILDS IN FROM THE WEST...BECOMING CENTERED OVER LAKE
MICHIGAN ON MONDAY. LOW PRESSURE WILL DEVELOP OVER THE CENTRAL
PLAINS MONDAY...THEN LIFT NORTHEAST TO LAKE MICHIGAN LATE THURSDAY
INTO EARLY FRIDAY.
BMD
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...FLASH FLOOD WATCH...ILZ021-ILZ022-ILZ023-ILZ032-ILZ033-ILZ039
UNTIL 7 PM SATURDAY.
IN...FLASH FLOOD WATCH...INZ001-INZ002-INZ010-INZ011-INZ019 UNTIL 7
PM SATURDAY.
LM...DENSE FOG ADVISORY...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ868-LMZ870-
LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 9 PM SATURDAY.
SMALL CRAFT ADVISORY...INDIANA NEARSHORE WATERS UNTIL 10 PM FRIDAY.
&&
$$
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
736 PM CDT FRI MAY 31 2013
.DISCUSSION...
336 PM CDT
THOUGHTS FROM THE EARLIER MESO DISCUSSION ARE STILL VALID AND HAVE
BEEN BOLSTERED BY THE SPREAD OF SHOWERS WITH ISOLATED TSRA INTO THE
FCST AREA THIS AFTERNOON WITH LITTLE ADDITIONAL DEVELOPMENT DIRECTLY
WEST OVER IOWA SO FAR. 0-6 KM BULK SHEAR CONTINUES TO BE MARGINAL
OVER MOST OF THE LOCAL REGION BUT IS BUILDING TOWARD 40 KTS IN THE
AREA OF APPROACHING CONVECTION TO OUR SOUTHWEST UNDER THE LEADING
EDGE OF AN UPPER LEVEL JET. A FEW STORMS COULD BECOME ORGANIZED IN
SOUTHERN PORTIONS OF THE CWA...THOUGH THE SEVERE RISK OVERALL
APPEARS TO BE MARGINAL. TRENDS FOR THIS EVENING AND OVERNIGHT
ALSO WOULD CONTINUE TO FAVOR SOUTHERN PORTIONS OF THE CWA FOR THE
HEAVIEST RAINFALL AMOUNTS AND THE CORRESPONDING FLOOD RISK...AND
THIS ALSO IS WHERE THE MOST RAIN HAS FALLEN OVER THE PAST WEEK. FOR
THESE REASONS...AFTER COORDINATION WITH NEIGHBORS...WILL PLAN TO
DROP THE FLOOD WATCH FOR NORTHERN PORTIONS OF THE FORECAST AREA.
ALL OF THIS ACTIVITY IS BEING DRIVEN BY RICH BOUNDARY LAYER GULF
MOISTURE WRAPPING AROUND THE WESTERN SIDE OF A BERMUDA HIGH...AND
AHEAD OF AN APPROACHING FRONTAL ZONE TIED TO LOW PRESSURE OVER THE
DAKOTAS. THIS FRONTAL ZONE PUSHES THROUGH THE AREA SATURDAY NIGHT
AND USHERS IN COOLER AND DRIER AIR FOR THE FIRST HALF OF NEXT WEEK.
UNSETTLED WEATHER WILL PERSIST UNTIL THAT TIME WITH THE FOCUS
GRADUALLY SHIFTING EASTWARD. SHOWER AND THUNDERSTORM FORECAST
TRENDS FOR THIS EVENING AND OVERNIGHT ARE BASED ON CURRENT ACTIVITY
AND THE IDEA OF INCREASING DEVELOPMENT SUPPORTED BY LOW LEVEL
MOISTURE CONVERGENCE BEING DEPICTED IN THE RAP MODEL. IF THESE RAP
FIELDS CONTINUE TO BE VALID TOWARD MORNING...THE NORTHWEST HALF OF
THE AREA WOULD APPEAR TO DRY OUT BY MIDNIGHT AND REMAIN SO INTO THE
MORNING HOURS. THIS TREND ALSO IS SUPPORTED BY THE LATEST
NAM/ECMWF/GFS QPF FIELDS. CHANCES THEN INCREASE AGAIN DURING THE
DAY TOMORROW AHEAD OF THE APPROACHING UPPER LEVEL VORT MAX AND THE
SURFACE FRONTAL ZONE.
AFTER A COOLER AND DRIER END TO THE WEEKEND AND START TO THE WORK
WEEK...THE NEXT UPPER TROUGH AND SFC LOW BEGIN TO APPROACH THE
AREA TOWARD THE MIDDLE OF NEXT WEEK ALONG THE SIMILAR DAKOTAS TRACK
THAT WE HAVE SEEN WITH THE CURRENT SYSTEM. SFC WINDS TURNING
SOUTHEAST BY WEDNESDAY AND SOUTH BY THURSDAY WOULD ALLOW WARM MOIST
GULF AIR TO START WORKING BACK INTO THE AREA FOR LATE NEXT
WEEK...BUT AT THIS RANGE WILL ONLY PLAN TO CARRY CHANCE POPS.
LENNING
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 00Z...
* MVFR CIGS POSSIBLE TONIGHT
* CHANCE OF TSRA SAT AFTERNOON
IZZI
//DISCUSSION...UPDATED 00Z...
POCKETS OF MVFR CIGS BLOSSOMING IN THE VERY MOIST AIR MASS OVER
WESTERN ILLINOIS WITH SOME CONCERN THAT THESE CIGS COULD CONTINUE
TO EXPAND EASTWARD INTO CHGO AREA AFTER SUNSET. WHEN/IF CIGS MOVE
IN CERTAINLY PLAUSIBLE THAT THEY COULD LINGER THROUGH TONIGHT AND
POSSIBLY INTO SATURDAY MORNING. ASSUMING MVFR CIGS DO DEVELOP THEN
THEY WOULD LIKELY LIFT TO VFR DURING THE MORNING SATURDAY.
ADDITIONAL SHOWERS AND THUNDERSTORMS COULD DEVELOP SATURDAY
AFTERNOON AS WE REMAIN REMAIN AHEAD OF THE FRONT AND IN THE
WARM/HUMID AIR MASS. MODELS CONTINUE TO STRUGGLE WITH THE PRECISE
DETAILS OF CONVECTIVE EVOLUTION HOWEVER CURRENT INDICATIONS ARE
THE BETTER THREAT OF THUNDERSTORMS ON SATURDAY MAY END UP BEING
SOUTH OF THE CHICAGO AREA TERMINALS.
IZZI
//ORD AND MDW CONFIDENCE...UPDATED 00Z...
* MEDIUM-HIGH CONFIDENCE IN DRY FORECAST THROUGH SATURDAY MORNING
* LOW-MEDIUM CONFIDENCE IN CIGS TONIGHT INTO SATURDAY MORNING
* LOW CONFIDENCE IN TSRA CHANCES SAT AFTERNOON
IZZI
//OUTLOOK FOR ORD/MDW FOR 12Z SUNDAY-12Z FRIDAY...UPDATED 00Z...
SUNDAY THROUGH TUESDAY...VFR.
WEDNESDAY AND THURSDAY...CHANCE OF TSRA.
IZZI
&&
.MARINE...
222 PM CDT
AN AREA OF LOW PRESSURE THAT HAS PERSISTED OVER THE NORTHERN PLAINS
WILL FINALLY BEGIN TO MOVE EAST TONIGHT...PASSING OVER NORTHERN LAKE
MICHIGAN LATE SATURDAY EVENING WITH A TRAILING COLD FRONT TURNING
MODERATE SOUTHERLY WINDS OF 15 TO 25 KT TO NORTHWESTERLY. MOIST FLOW
AHEAD OF THE FRONT HAS ALREADY LED TO DENSE FOG OVER MUCH OF THE
LAKE WHICH IS EXPECTED TO PERSIST UNTIL THE COLD FRONT PASSES
SATURDAY NIGHT. WINDS SHOULD THEN DIMINISH THROUGH THE DAY SUNDAY AS
HIGH PRESSURE BUILDS IN FROM THE WEST...BECOMING CENTERED OVER LAKE
MICHIGAN ON MONDAY. LOW PRESSURE WILL DEVELOP OVER THE CENTRAL
PLAINS MONDAY...THEN LIFT NORTHEAST TO LAKE MICHIGAN LATE THURSDAY
INTO EARLY FRIDAY.
BMD
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...FLASH FLOOD WATCH...ILZ021-ILZ022-ILZ023-ILZ032-ILZ033-ILZ039
UNTIL 7 PM SATURDAY.
IN...FLASH FLOOD WATCH...INZ001-INZ002-INZ010-INZ011-INZ019 UNTIL 7
PM SATURDAY.
LM...DENSE FOG ADVISORY...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ868-LMZ870-
LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 9 PM SATURDAY.
SMALL CRAFT ADVISORY...INDIANA NEARSHORE WATERS UNTIL 10 PM FRIDAY.
&&
$$
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
539 PM CDT THU MAY 30 2013
.DISCUSSION...
504 PM CDT
HAVE DECIDED TO EXPAND THE CURRENT FLASH FLOOD WATCH...TO INCLUDE
THE ENTIRE CWA.
WAS ON THE FENCE EARLIER WITH REGARDS TO EXPANDING THE CURRENT
FLASH FLOOD WATCH FOR THE REMAINDER OF THE CWA...BUT WITH LATEST
TRENDS THIS PAST AFTERNOON...HAVE DECIDED TO INCLUDE THE ENTIRE
CWA. THE THUNDERSTORMS THIS PAST AFTERNOON HAVE BEEN VERY GOOD
RAIN PRODUCERS...WHICH WILL LIKELY CONTINUE OVER THE NEXT COUPLE
OF HOURS AS PWATS REMAIN RATHER HIGH. ALSO...MONITORING THE
CONVECTIVE LINE TO THE WEST AND ITS MOVEMENT EAST INTO THE CWA.
LATEST TRENDS AND SHORT TERM GUIDANCE ARE HINTING AT THE
POSSIBILITY OF MORE TRAINING ACROSS THE CWA...WITH CURRENT FLOW IN
PLACE...DEFINITELY SEEMS REASONABLE.
RODRIGUEZ
//PREV DISCUSSION...
400 PM CDT
MAIN FORECAST CONCERNS REMAIN TIED TO THE ACTIVE WEATHER PATTERN
EXPECTED THROUGH THE START OF THE WEEKEND...WITH ROUNDS OF HEAVY
RAINFALL LIKELY AS WELL AS CONTINUED CHANCES FOR SEVERE WEATHER.
HAVE NOT EXPANDED THE FFA WATCH AT THIS TIME WITH MORE WIDESPREAD
HEAVY RAINFALL AND FLOODING NOT APPEARING LIKELY UNTIL LATER
FRIDAY AFTERNOON INTO FRIDAY NIGHT. THIS IS NOT TO SAY THAT
LOCALIZED FLOODING COULD NOT OCCUR WITH ANY POSSIBLE STRONG
THUNDERSTORMS TONIGHT. A MORE LIKELY SCENARIO AT THIS TIME IS WITH
THE CURRENT SCATTERED DEVELOPMENT TO BE REPLACED WITH A MORE
PROGRESSIVE AREA OF THUNDERSTORMS.
CURRENT ISOLATED TO SCATTERED ACTIVITY ACROSS THE CWA WILL
CONTINUE TO INCREASE IN COVERAGE THIS EVENING...AS LARGE SCALE
FORCING INCREASES WITH THE APPROACH A FAIRLY STOUT MID LEVEL WAVE
PROPAGATING NORTH THROUGH CENTRAL ILLINOIS. AREAS WHICH CONTINUE
TO BE FAVORED ARE LOCATIONS ALONG AND WEST OF A LINE FROM CRYSTAL
LAKE SOUTH TO GIBSON CITY IN ILLINOIS. LATEST RAP ANALYSIS SHOWS
MODERATE INSTABILITY IN PLACE WITH MLCAPE AROUND 2000 J/KG...AND
WITH MID/LOW LEVEL LAPSE RATES EXPECTED TO ONLY INCREASE OVER THE
NEXT COUPLE OF HOURS. THIS INCREASING FORCING AND INSTABILITY WILL
AID FURTHER DEVELOPMENT/EXPANSION OF CURRENT ACTIVITY ONGOING
ACROSS THE WESTERN HALF OF THE CWA. DEEP LAYER SHEAR REMAINS
MEAGER AT 25-30KT PRIMARILY OVER THE WESTERN CWA WHILE 0-1KM SHEAR
ALSO REMAINS HIGHEST ALONG OR JUST WEST OF THE CWA...ESPECIALLY
GOING INTO WESTERN ILLINOIS AND EASTERN IOWA.
HOWEVER...SHORT TERM GUIDANCE CONTINUES TO SHOW AN INCREASE IN
BOTH DEEP LAYER SHEAR AND LOW LEVEL SHEAR ACROSS THE CURRENT WATCH
AREA THROUGH THE REMAINDER OF THE AFTERNOON. THIS WILL HELP FOR
MORE ORGANIZED AND LONGER LIVED DEVELOPMENT ACROSS THE WESTERN
CWA...LEAVING THE THREAT OF HAIL/DAMAGING WINDS AS WELL AS
POSSIBLE TORNADOES. ALTHOUGH MORE ORGANIZED DEVELOPMENT IS MORE
LIKELY FOR THE WESTERN HALF OF THE CWA...SHORT TERM GUIDANCE IS
HINTING AT A SLIGHT INCREASE IN DEEP LAYER SHEAR MORE TOWARDS FAR
NORTHEAST ILLINOIS. THIS SLIGHT INCREASE COINCIDING WITH THE
CURRENT CAPE IN PLACE...COULD FAVOR SOME ISOLATED STRONGER
DEVELOPMENT IN THAT LOCATION IN THE NEXT COUPLE OF HOURS. WILL
NEED CONTINUE TO MONITOR DEVELOPMENT IN THAT LOCATION...WHICH
WOULD INCLUDE THE CITY OF CHICAGO/METRO AREA LATE THIS AFTERNOON
INTO THE EARLY EVENING...AS I COULD EASILY FORESEE AN UPSCALE IN
GROWTH IN BOTH INTENSITY AND COVERAGE.
EVEN IF THAT DOES NOT MATERIALIZE THROUGH LATE THIS
AFTERNOON...CONTINUE TO MONITOR A LARGER LINE OF THUNDERSTORMS
SITUATED FROM SOUTHERN IOWA SOUTH INTO MISSOURI. THIS LINE IS TIED
MORE CLOSELY TO FAIRLY STRONG MID LEVEL WAVE LIFTING NORTHEAST OUT
KANSAS AND ATTENDANT SURFACE TROUGH/BOUNDARY FROM IOWA INTO
MISSOURI. ALL GUIDANCE IS SHOWING THIS LINE OF THUNDERSTORMS
WILL INCREASE IN INTENSITY OVER THE NEXT COUPLE OF HOURS...WHICH
WOULD MAKE SENSE AS THIS LINE OF THUNDERSTORMS MOVES FURTHER
EAST/NORTHEAST INTO A MORE UNSTABLE ENVIRONMENT. STRONG FORCING
OWING TO LARGE SCALE SUPPORT AND LOW/MID LEVEL CONVERGENCE SHOULD
AID IN THIS LINE OF THUNDERSTORMS FURTHER BLOSSOMING AS IT MOVES
TOWARDS THE WESTERN ILLINOIS...ESPECIALLY AS DEEP LAYER SHEAR IS
ALSO INCREASING.
THERE IS STILL SOME UNCERTAINTY AS TO THE WHOLE EVOLUTION OF THIS
LINE OF THUNDERSTORMS AS IT WORKS ITS WAY TOWARDS NORTHERN
ILLINOIS THIS EVENING...MAINLY IN THE STRENGTH OF THIS COMPLEX AND
POTENTIAL SEVERE THREAT. ALTHOUGH THERE WILL BE SOME SLIGHT
DIMINISHING TREND WITH THE CURRENT INSTABILITY IN PLACE...FEEL
THAT IT WILL MORE THAN SUFFICE TO HELP KEEP THIS LINE SHIFTING
EAST. ALSO...SHORT TERM GUIDANCE IS INDICATING THAT 0-3KM BULK
SHEAR WILL INCREASE TOWARDS THE 00Z TIME FRAME THIS
EVENING...WHICH WOULD ACT TO HELP FOR ORGANIZATION AND INCREASE IN
THREAT FOR LINEAR STRUCTURES/STRONG DAMAGING WINDS. SO HAVE
TRENDED MORE PESSIMISTIC...WITH THINKING THAT THIS LINE AND STRONG
DAMAGING WINDS COULD MOVE ACROSS NORTHERN ILLINOIS THIS EVENING.
HAVE ALSO TRENDED MORE TOWARDS THE HRRR...WITH SYSTEM TIMING
THINKING THAT IT SHOULD BE KNOCKING ON THE WESTERN CWA DOORSTEPS
BY 00-01Z AND THEN CONTINUE EAST TOWARDS NORTHEAST ILLINOIS
THROUGH THE SEVERAL HOURS THERE AFTER. BEYOND THAT TIME
FRAME...CONFIDENCE LOWERS WITH REGARDS TO THE STRENGTH OF THIS
SYSTEM. NONETHELESS...HEAVY RAINFALL AND FLASH FLOODING COULD
BECOME ISSUES OVERNIGHT TONIGHT ESPECIALLY AS PWATS ARE AT OR JUST
ABOVE 1.7 INCHES AND 850MB DEW POINTS REMAIN RATHER HIGH.
THUNDERSTORM COMPLEX IS THEN EXPECTED TO SHIFT EAST OF THE CWA BY
EARLY FRIDAY MORNING...WITH A DRYING TREND EXPECTED DURING THAT
TIME FRAME. THIS SHOULD NOT LAST TOO LONG WITH DRY CONDITIONS ONLY
EXPECTED THROUGH MID DAY AS ATTENTION QUICKLY SHIFTS BACK WEST
WITH THE APPROACH OF ANOTHER STRONG MID LEVEL WAVE EJECTING OUT OF
THE CENTRAL PLAINS. YET AGAIN...A SEVERE THREAT WILL BE IN PLACE
ON FRIDAY WITH GROWING CONCERNS OF MORE POTENTIAL FLOODING FROM
THIS POINT ON...INTO FRIDAY NIGHT AND SATURDAY. THE SEVERE THREAT
WILL LIKELY AFFECT THE ENTIRE CWA ON FRIDAY AND WITH CLEARING
ANTICIPATED FRIDAY MORNING...INSTABILITY IS EXPECTED TO RAPIDLY
INCREASE BY LATE MORNING WITH MODERATE TO STRONG INSTABILITY
LIKELY IN PLACE ACROSS THE CWA. STRONG DEEP LAYER SHEAR IN UPWARDS
OF 50-60KT WILL EASILY SUPPORT WIDESPREAD ORGANIZED DEVELOPMENT AS
SOON AS EARLY AFTERNOON ON FRIDAY. STRONG DAMAGING WINDS AND HAIL
ARE THE MAIN THREAT...BUT WITH SREF GUIDANCE INDICATING ELEMENTS
CORRESPONDING TO SUPERCELLULAR STRUCTURES OR ROTATING
THUNDERSTORMS COULD COME TOGETHER ACROSS THE CWA. WILL NEED TO
CONTINUE TO MONITOR THIS TIME FRAME AS WELL...AS WIDESPREAD SEVERE
IS APPEARING LIKELY ONCE AGAIN. GOING INTO FRIDAY NIGHT...HEAVY
RAINFALL APPEARS LIKELY WITH SEVERAL STRONG WAVES PROPAGATING
NORTHEAST ACROSS THE CWA PROVIDING CONTINUED DEVELOPMENT AS WELL
AS A STRONG LLJ ORIENTED TOWARDS NORTHEAST ILLINOIS...PUMPING HIGH
THETAE AIR INTO THE REGION.
RODRIGUEZ
EXTENDED PERIOD...SUNDAY THROUGH THURSDAY...
BY DAYBREAK SUNDAY THE UPPER RIDGE IS TO HAVE PROGRESSED EASTWARD
TO OVER THE UPPER MIDWEST AND MID MS VALLEY WITH A SURFACE
TROUGH/SECONDARY COLD FRONT JUST TO THE NORTHWEST AND NORTH OF THE
LOCAL FORECAST AREA. THIS TROUGH/FRONT IS PROGGED TO MOVE ACROSS ALL
OF THE FA DURING THE SUNDAY MORNING AS THE UPPER TROUGH CONTINUES ON
TO OVER THE UPPER GREAT LAKES AND LOWER OH VALLEY BY EVENING. UNTIL
THE TROUGH AXIS MOVES A BIT FURTHER EAST OF THE IMMEDIATE AREA THERE
WILL BE A LINGERING CHANCE OF SHOWERS DURING SUNDAY MORNING.
THE SECONDARY COLD FRONT WILL REINFORCE THE COLD AIR ADVECTION THAT
WILL HAVE STARTED TO OCCUR LATE SATURDAY AND SATURDAY NIGHT WITH THE
INITIAL COLD FRONT. BETWEEN THE PAIR OF FRONT 850HPA TEMPERATURES
ARE PROGGED TO FALL AROUND 10 DEGREES C FROM 18Z SATURDAY TO 00Z
MONDAY......DOWN TO AROUND +4 OR +5C. WITH COOL HIGH PRESSURE
BUILDING OVER THE AREA TEMPERATURES WILL BE COOL SUNDAY AND MONDAY
WITH HIGHS ONLY IN THE 60S...WITH LAKESIDE MAX TEMPERATURES LIKELY
TO ONLY BE IN THE 55-60F RANGE AS A LONG FETCH DOWN LAKE MICHIGAN
BRINGS AIR ADDITIONALLY COOLED BY THE STILL CHILLY LAKE ASHORE
SUNDAY. WHILE THE SURFACE RIDGE AXIS WILL BE MOVING OVER WI AND
WESTERN IL DURING MONDAY ALLOWING WINDS TO SLACKEN...A WEAK NE
SYNOPTIC FLOW WILL STILL BE IN PLACE AIDED BY A LAKE BREEZE.
THE FURTHER EASTWARD PROGRESS OF THE UPPER TROUGH IS TO BE SLOW AS A
CLOSED LOW TO FORM OVER SOUTHERN HUDSON BAY/NORTHERN ONTARIO IS
PROGGED TO BE DROP SOUTH...THEN SOUTHEAST AND EAST OVER ONTARIO
SATURDAY NIGHT THROUGH MONDAY NIGHT. AS THE UPPER TROUGH/LOW MOVES
FURTHER EAST A WEAK UPPER RIDGE WILL MOVE OVER THE REGION TUESDAY AS
ANOTHER UPPER LOW MOVES EAST OVER THE FAR SOUTHERN CANADIAN
PRAIRIE/FAR NORTHERN PLAINS. THIS WILL ALLOW A BIT OF MODERATION IN
TEMPERATURES TUESDAY AND WEDNESDAY AS EAST-SOUTHEAST WINDS BECOMES
SOUTHEASTERLY AND INCREASING THOUGH THIS LOW LEVEL FLOW WILL KEEP
THE IL SHORE...ESPECIALLY THE FAR NORTHERN PART....STILL CHILLY.
INLAND AREAS SHOULD PEAK IN THE UPPER 60S AND LOWER 70S TUESDAY...
AND A COUPLE DEGREES WARMER WEDNESDAY. WITH CONTINUED WARM AIR
ADVECTION AHEAD OF THE APPROACHING UPPER LOW/TROUGH THE WARMING
TREND WILL CONTINUE THURSDAY WITH MOST LOCATIONS REACHING THE MID
AND UPPER 70S THOUGH THERE WILL STILL BE AN EASTERLY COMPONENT TO
THE LOW LEVEL FLOW TO KEEP THE IL SHORELINE IN THE 60S.
TRS
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 22Z...
* APPROACHING LINE OF STORMS / LARGE OW ECHO ON WEATHER RADAR /
EXPECTED TO ACCELERATE ACROSS NORTHERN ILLINOIS THIS EVENING.
* GUST FRONT AHEAD OF LINE OF STORMS MAY PRODUCE DAMAGING WIND
GUSTS... IN ADDITIONAL TO BRIEF TORRENTIAL RAINFALL.
* ONGOING SCATTERED THUNDERSTORMS CONTINUING ALTHOUGH DECREASING
IN COVERAGE INTO THE EVENING AHEAD OF APPROACHING LINE OF
STORMS.
ED F
//DISCUSSION...UPDATED 18Z...
AN ACTIVE PERIOD IS EXPECTED WITH SEVERAL BOUTS OF THUNDERSTORMS
POSSIBLE AND GUSTY SOUTHERLY WINDS.
SYNOPTICALLY...AREA OF LOW PRESSURE LIES OVER THE NORTHERN PLAIN AND
WILL GRADUALLY SHIFT NORTHEAST THROUGH THE TAF PERIOD. NORTHERN
ILLINOIS LIES IN A TIGHT SOUTHERLY GRADIENT WITH WINDS GUSTING TO
AROUND 30 KT ALREADY EARLY THIS AFTERNOON AND EXPECTED TO PERSIST
THROUGH THE DAY. WINDS MAY TAPER SOME WITH SUNSET...THEN ARE
EXPECTED TO BECOME GUSTY AGAIN FRIDAY...THOUGH NOT QUITE AS STRONG
AS TODAY.
SEVERAL ROUNDS OF THUNDERSTORMS ARE POSSIBLE...WITH THE DETAILS
STILL A BIT MURKY. FIRST ROUND IS ALREADY STARTING TO TAKE SHAPE
THIS AFTERNOON AS STRONG INSTABILITY HAS DEVELOPED OVER THE AREA
WITH CONVECTION ALREADY DEVELOPING DOWNSTATE AHEAD OF A NEGATIVELY
TILTED TROUGH LIFTING ACROSS THE MID MISSISSIPPI VALLEY. THIS WAVE
WILL CONTINUE NORTHEAST INTO NORTHERN ILLINOIS MID AFTERNOON WITH
SCATTERED STRONG TO SEVERE THUNDERSTORMS EXPECTED OVER THE AREA.
WITH NO SIGNIFICANT LOW LEVEL BOUNDARIES OR FOCUSING MECHANISMS...IT
WILL BE HARD TO IMPOSSIBLE TO PINPOINT EXACTLY WHERE THUNDERSTORMS
WILL DEVELOP...THOUGH THE BEST INSTABILITY HAS SET UP JUST WEST OF
THE CHICAGO TERMINALS. THEN THIS EVENING...NUMEROUS CONVECTIVE
ALLOWING MODELS ARE INDICATING THAT A SECOND ROUND OF CONVECTION
WILL CONGEAL INTO A LINE OFF TO OUR WEST WITH THE DEVELOPMENT OF A
MODERATE TO STRONG LOW LEVEL JET ALONG THE MISSISSIPPI RIVER VALLEY.
THIS LINE IS EXPECTED TO RACE EAST LATE THIS EVENING OR EARLY
OVERNIGHT. FINALLY...WITH SIMILAR CONDITIONS IN PLACE
TOMORROW...WILL BE LOOKING AT MUCH OF THE SAME CONCERNS FRIDAY WITH
RESPECT TO PERIODIC CONVECTIVE CHANCES.
BMD
//ORD AND MDW CONFIDENCE...UPDATED 22Z...
* MEDIUM TO HIGH CONFIDENCE IN SCATTERED TSTMS CONTINUING THROUGH
THE EVENING... BUT WITH DECREASE IN COVERAGE OF SCATTERED CELLS
IN ADVANCE OF LARGE LINE OF STORMS.
* MEDIUM TO HIGH CONFIDENCE THAT APPROACHING LINE OF STORMS WILL
CONTINUE ACROSS NORTHERN ILLINOIS THIS EVENING.
* MEDIUM TO HIGH CONFIDENCE THAT LINE OF STORMS WILL MAINTAIN
INTENSITY AS IT MOVES EAST THROUGH 03Z.
* MEDIUM CONFIDENCE IN TIMING OF LINE OF TSTMS IMPACTING TERMINALS
AROUND MID EVENING.
* LOW CONFIDENCE IN STRENGTH OF WIND GUSTS TO BE EXPECTED AT
TERMINALS AS GUST FRONT WITH LINE OF STORMS ADVANCES.
* MEDIUM CONFIDENCE IN ADDITIONAL TSTMS FRIDAY...LOW CONFIDENCE
IN TIMING.
* MEDIUM TO HIGH CONFIDENCE IN WIND TRENDS.
ED F
//OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z...
* FRIDAY THROUGH SATURDAY...PERIODS OF TSRA/SHRA.
POSSIBLE WITH MVFR CIGS/VIS.
* SUNDAY...CHANCE OF SHRA EARLY...OTRW...VFR.
* MONDAY THROUGH EARLY TUESDAY...VFR. WX NIL.
* LATE TUESDAY THROUGH WEDNESDAY...CHANCE TSRA/SHRA.
KREIN
&&
.MARINE...
1259 PM CDT
THE SHORT TERM OF THE MARINE FORECAST HAS A SMALL CRAFT ADVISORY FOR
STRONG WINDS ACROSS THE ILLINOIS AND NORTHWEST INDIANA NEARSHORE
WATERS.
ACROSS THE OPEN WATERS OF THE LAKE...MAINLY THE NORTHERN THIRD OF
THE LAKE...AREAS OF DENSE FOG CONTINUE.
VERY WARM/MOIST AIR CONTINUES TO SLIDE NORTH ACROSS THE LAKE...AND
WITH THE MUCH COOLER LAKE SURFACE WATER...HAS RESULTED IN AREAS OF
DENSE FOG PERSISTING. IT DOES APPEAR BASED ON LATEST VISIBLE IMAGERY
THAT THE FOG HAS REMAINED FOCUSED ACROSS THE NORTHERN THIRD OF THE
LAKE. OBS HAVE CONTINUED TO SHOW INCREASING GUSTS...WITH SPEEDS
GENERALLY AROUND 20-25KT ACROSS THE SOUTHERN HALF OF THE LAKE.
FURTHER NORTH IT APPEARS THE WINDS ARE SLIGHTLY LESS...WITH SPEEDS
GENERALLY IN THE 15-25KT.
THE TROUGH OF LOW PRESSURE REMAINS CENTERED ACROSS THE CENTRAL
PLAINS...WITH A WEAK LOW PRESSURE LIFTING NORTH INTO THE NORTHERN
PLAINS. AN ASSOCIATED WARM FRONT EXTENDS EAST THROUGH THE UPPER
GREAT LAKES REGION. WITH THE POSITION OF THE LOW PRESSURE AND THE
PERSISTING RIDGE OF HIGH PRESSURE ACROSS THE SOUTHEASTERN UNITED
STATES...THE WIND FLOW WILL REMAIN SOUTHERLY ACROSS THE LAKE. AT
TIMES THROUGH EARLY THIS EVENING GUSTS MAY APPROACH 30 KT...MAINLY
FOR THE SOUTHERN PORTIONS OF THE LAKE INCLUDING THE NEARSHORE
WATERS. AS A RESULT WILL MAINTAIN THE CURRENT SMALL CRAFT ADVISORY
THAT IS IN EFFECT.
THE TROUGH OF LOW PRESSURE POSITIONED OVER THE CENTRAL PLAINS WILL
SLOWLY PUSH EAST...WITH A LOW PRESSURE APPROACHING THE WESTERN GREAT
LAKES SAT MIDDAY. THE RECENT FORECAST TRENDS HAVE BEEN TO SLOW THE
ARRIVAL OF THIS SYSTEM...THUS IT IS POSSIBLE THAT THE MAIN LOW
PRESSURE MAY NOT ARRIVE UNTIL CLOSER TO SAT NIGHT. THEN AN
ASSOCIATED COLD FRONT WILL WILL PUSH EAST ACROSS THE LAKE OVERNIGHT
SAT INTO SUN. WINDS AT THAT POINT WILL TURN WESTERLY THEN NORTHERLY
WITH MUCH COOLER AIR FLOWING OVER THE LAKE.
BEACHLER
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...FLASH FLOOD WATCH...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-ILZ010-
ILZ011-ILZ012-ILZ013-ILZ014-ILZ019-ILZ020-ILZ021-ILZ022-
ILZ023-ILZ032-ILZ033-ILZ039 UNTIL 7 PM SATURDAY.
IN...FLASH FLOOD WATCH...INZ001-INZ002-INZ010-INZ011-INZ019 UNTIL 7
PM SATURDAY.
LM...DENSE FOG ADVISORY...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565
UNTIL 7 AM FRIDAY.
SMALL CRAFT ADVISORY...NEARSHORE WATERS
UNTIL 9 PM THURSDAY.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
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WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
510 PM CDT THU MAY 30 2013
.DISCUSSION...
504 PM CDT
HAVE DECIDED TO EXPAND THE CURRENT FLASH FLOOD WATCH...TO INCLUDE
THE ENTIRE CWA.
WAS ON THE FENCE EARLIER WITH REGARDS TO EXPANDING THE CURRENT
FLASH FLOOD WATCH FOR THE REMAINDER OF THE CWA...BUT WITH LATEST
TRENDS THIS PAST AFTERNOON...HAVE DECIDED TO INCLUDE THE ENTIRE
CWA. THE THUNDERSTORMS THIS PAST AFTERNOON HAVE BEEN VERY GOOD
RAIN PRODUCERS...WHICH WILL LIKELY CONTINUE OVER THE NEXT COUPLE
OF HOURS AS PWATS REMAIN RATHER HIGH. ALSO...MONITORING THE
CONVECTIVE LINE TO THE WEST AND ITS MOVEMENT EAST INTO THE CWA.
LATEST TRENDS AND SHORT TERM GUIDANCE ARE HINTING AT THE
POSSIBILITY OF MORE TRAINING ACROSS THE CWA...WITH CURRENT FLOW IN
PLACE...DEFINITELY SEEMS REASONABLE.
RODRIGUEZ
&&
.PREV DISCUSSION...
400 PM CDT
MAIN FORECAST CONCERNS REMAIN TIED TO THE ACTIVE WEATHER PATTERN
EXPECTED THROUGH THE START OF THE WEEKEND...WITH ROUNDS OF HEAVY
RAINFALL LIKELY AS WELL AS CONTINUED CHANCES FOR SEVERE WEATHER.
HAVE NOT EXPANDED THE FFA WATCH AT THIS TIME WITH MORE WIDESPREAD
HEAVY RAINFALL AND FLOODING NOT APPEARING LIKELY UNTIL LATER
FRIDAY AFTERNOON INTO FRIDAY NIGHT. THIS IS NOT TO SAY THAT
LOCALIZED FLOODING COULD NOT OCCUR WITH ANY POSSIBLE STRONG
THUNDERSTORMS TONIGHT. A MORE LIKELY SCENARIO AT THIS TIME IS WITH
THE CURRENT SCATTERED DEVELOPMENT TO BE REPLACED WITH A MORE
PROGRESSIVE AREA OF THUNDERSTORMS.
CURRENT ISOLATED TO SCATTERED ACTIVITY ACROSS THE CWA WILL
CONTINUE TO INCREASE IN COVERAGE THIS EVENING...AS LARGE SCALE
FORCING INCREASES WITH THE APPROACH A FAIRLY STOUT MID LEVEL WAVE
PROPAGATING NORTH THROUGH CENTRAL ILLINOIS. AREAS WHICH CONTINUE
TO BE FAVORED ARE LOCATIONS ALONG AND WEST OF A LINE FROM CRYSTAL
LAKE SOUTH TO GIBSON CITY IN ILLINOIS. LATEST RAP ANALYSIS SHOWS
MODERATE INSTABILITY IN PLACE WITH MLCAPE AROUND 2000 J/KG...AND
WITH MID/LOW LEVEL LAPSE RATES EXPECTED TO ONLY INCREASE OVER THE
NEXT COUPLE OF HOURS. THIS INCREASING FORCING AND INSTABILITY WILL
AID FURTHER DEVELOPMENT/EXPANSION OF CURRENT ACTIVITY ONGOING
ACROSS THE WESTERN HALF OF THE CWA. DEEP LAYER SHEAR REMAINS
MEAGER AT 25-30KT PRIMARILY OVER THE WESTERN CWA WHILE 0-1KM SHEAR
ALSO REMAINS HIGHEST ALONG OR JUST WEST OF THE CWA...ESPECIALLY
GOING INTO WESTERN ILLINOIS AND EASTERN IOWA.
HOWEVER...SHORT TERM GUIDANCE CONTINUES TO SHOW AN INCREASE IN
BOTH DEEP LAYER SHEAR AND LOW LEVEL SHEAR ACROSS THE CURRENT WATCH
AREA THROUGH THE REMAINDER OF THE AFTERNOON. THIS WILL HELP FOR
MORE ORGANIZED AND LONGER LIVED DEVELOPMENT ACROSS THE WESTERN
CWA...LEAVING THE THREAT OF HAIL/DAMAGING WINDS AS WELL AS
POSSIBLE TORNADOES. ALTHOUGH MORE ORGANIZED DEVELOPMENT IS MORE
LIKELY FOR THE WESTERN HALF OF THE CWA...SHORT TERM GUIDANCE IS
HINTING AT A SLIGHT INCREASE IN DEEP LAYER SHEAR MORE TOWARDS FAR
NORTHEAST ILLINOIS. THIS SLIGHT INCREASE COINCIDING WITH THE
CURRENT CAPE IN PLACE...COULD FAVOR SOME ISOLATED STRONGER
DEVELOPMENT IN THAT LOCATION IN THE NEXT COUPLE OF HOURS. WILL
NEED CONTINUE TO MONITOR DEVELOPMENT IN THAT LOCATION...WHICH
WOULD INCLUDE THE CITY OF CHICAGO/METRO AREA LATE THIS AFTERNOON
INTO THE EARLY EVENING...AS I COULD EASILY FORESEE AN UPSCALE IN
GROWTH IN BOTH INTENSITY AND COVERAGE.
EVEN IF THAT DOES NOT MATERIALIZE THROUGH LATE THIS
AFTERNOON...CONTINUE TO MONITOR A LARGER LINE OF THUNDERSTORMS
SITUATED FROM SOUTHERN IOWA SOUTH INTO MISSOURI. THIS LINE IS TIED
MORE CLOSELY TO FAIRLY STRONG MID LEVEL WAVE LIFTING NORTHEAST OUT
KANSAS AND ATTENDANT SURFACE TROUGH/BOUNDARY FROM IOWA INTO
MISSOURI. ALL GUIDANCE IS SHOWING THIS LINE OF THUNDERSTORMS
WILL INCREASE IN INTENSITY OVER THE NEXT COUPLE OF HOURS...WHICH
WOULD MAKE SENSE AS THIS LINE OF THUNDERSTORMS MOVES FURTHER
EAST/NORTHEAST INTO A MORE UNSTABLE ENVIRONMENT. STRONG FORCING
OWING TO LARGE SCALE SUPPORT AND LOW/MID LEVEL CONVERGENCE SHOULD
AID IN THIS LINE OF THUNDERSTORMS FURTHER BLOSSOMING AS IT MOVES
TOWARDS THE WESTERN ILLINOIS...ESPECIALLY AS DEEP LAYER SHEAR IS
ALSO INCREASING.
THERE IS STILL SOME UNCERTAINTY AS TO THE WHOLE EVOLUTION OF THIS
LINE OF THUNDERSTORMS AS IT WORKS ITS WAY TOWARDS NORTHERN
ILLINOIS THIS EVENING...MAINLY IN THE STRENGTH OF THIS COMPLEX AND
POTENTIAL SEVERE THREAT. ALTHOUGH THERE WILL BE SOME SLIGHT
DIMINISHING TREND WITH THE CURRENT INSTABILITY IN PLACE...FEEL
THAT IT WILL MORE THAN SUFFICE TO HELP KEEP THIS LINE SHIFTING
EAST. ALSO...SHORT TERM GUIDANCE IS INDICATING THAT 0-3KM BULK
SHEAR WILL INCREASE TOWARDS THE 00Z TIME FRAME THIS
EVENING...WHICH WOULD ACT TO HELP FOR ORGANIZATION AND INCREASE IN
THREAT FOR LINEAR STRUCTURES/STRONG DAMAGING WINDS. SO HAVE
TRENDED MORE PESSIMISTIC...WITH THINKING THAT THIS LINE AND STRONG
DAMAGING WINDS COULD MOVE ACROSS NORTHERN ILLINOIS THIS EVENING.
HAVE ALSO TRENDED MORE TOWARDS THE HRRR...WITH SYSTEM TIMING
THINKING THAT IT SHOULD BE KNOCKING ON THE WESTERN CWA DOORSTEPS
BY 00-01Z AND THEN CONTINUE EAST TOWARDS NORTHEAST ILLINOIS
THROUGH THE SEVERAL HOURS THERE AFTER. BEYOND THAT TIME
FRAME...CONFIDENCE LOWERS WITH REGARDS TO THE STRENGTH OF THIS
SYSTEM. NONETHELESS...HEAVY RAINFALL AND FLASH FLOODING COULD
BECOME ISSUES OVERNIGHT TONIGHT ESPECIALLY AS PWATS ARE AT OR JUST
ABOVE 1.7 INCHES AND 850MB DEW POINTS REMAIN RATHER HIGH.
THUNDERSTORM COMPLEX IS THEN EXPECTED TO SHIFT EAST OF THE CWA BY
EARLY FRIDAY MORNING...WITH A DRYING TREND EXPECTED DURING THAT
TIME FRAME. THIS SHOULD NOT LAST TOO LONG WITH DRY CONDITIONS ONLY
EXPECTED THROUGH MID DAY AS ATTENTION QUICKLY SHIFTS BACK WEST
WITH THE APPROACH OF ANOTHER STRONG MID LEVEL WAVE EJECTING OUT OF
THE CENTRAL PLAINS. YET AGAIN...A SEVERE THREAT WILL BE IN PLACE
ON FRIDAY WITH GROWING CONCERNS OF MORE POTENTIAL FLOODING FROM
THIS POINT ON...INTO FRIDAY NIGHT AND SATURDAY. THE SEVERE THREAT
WILL LIKELY AFFECT THE ENTIRE CWA ON FRIDAY AND WITH CLEARING
ANTICIPATED FRIDAY MORNING...INSTABILITY IS EXPECTED TO RAPIDLY
INCREASE BY LATE MORNING WITH MODERATE TO STRONG INSTABILITY
LIKELY IN PLACE ACROSS THE CWA. STRONG DEEP LAYER SHEAR IN UPWARDS
OF 50-60KT WILL EASILY SUPPORT WIDESPREAD ORGANIZED DEVELOPMENT AS
SOON AS EARLY AFTERNOON ON FRIDAY. STRONG DAMAGING WINDS AND HAIL
ARE THE MAIN THREAT...BUT WITH SREF GUIDANCE INDICATING ELEMENTS
CORRESPONDING TO SUPERCELLULAR STRUCTURES OR ROTATING
THUNDERSTORMS COULD COME TOGETHER ACROSS THE CWA. WILL NEED TO
CONTINUE TO MONITOR THIS TIME FRAME AS WELL...AS WIDESPREAD SEVERE
IS APPEARING LIKELY ONCE AGAIN. GOING INTO FRIDAY NIGHT...HEAVY
RAINFALL APPEARS LIKELY WITH SEVERAL STRONG WAVES PROPAGATING
NORTHEAST ACROSS THE CWA PROVIDING CONTINUED DEVELOPMENT AS WELL
AS A STRONG LLJ ORIENTED TOWARDS NORTHEAST ILLINOIS...PUMPING HIGH
THETAE AIR INTO THE REGION.
RODRIGUEZ
EXTENDED PERIOD...SUNDAY THROUGH THURSDAY...
BY DAYBREAK SUNDAY THE UPPER RIDGE IS TO HAVE PROGRESSED EASTWARD
TO OVER THE UPPER MIDWEST AND MID MS VALLEY WITH A SURFACE
TROUGH/SECONDARY COLD FRONT JUST TO THE NORTHWEST AND NORTH OF THE
LOCAL FORECAST AREA. THIS TROUGH/FRONT IS PROGGED TO MOVE ACROSS ALL
OF THE FA DURING THE SUNDAY MORNING AS THE UPPER TROUGH CONTINUES ON
TO OVER THE UPPER GREAT LAKES AND LOWER OH VALLEY BY EVENING. UNTIL
THE TROUGH AXIS MOVES A BIT FURTHER EAST OF THE IMMEDIATE AREA THERE
WILL BE A LINGERING CHANCE OF SHOWERS DURING SUNDAY MORNING.
THE SECONDARY COLD FRONT WILL REINFORCE THE COLD AIR ADVECTION THAT
WILL HAVE STARTED TO OCCUR LATE SATURDAY AND SATURDAY NIGHT WITH THE
INITIAL COLD FRONT. BETWEEN THE PAIR OF FRONT 850HPA TEMPERATURES
ARE PROGGED TO FALL AROUND 10 DEGREES C FROM 18Z SATURDAY TO 00Z
MONDAY......DOWN TO AROUND +4 OR +5C. WITH COOL HIGH PRESSURE
BUILDING OVER THE AREA TEMPERATURES WILL BE COOL SUNDAY AND MONDAY
WITH HIGHS ONLY IN THE 60S...WITH LAKESIDE MAX TEMPERATURES LIKELY
TO ONLY BE IN THE 55-60F RANGE AS A LONG FETCH DOWN LAKE MICHIGAN
BRINGS AIR ADDITIONALLY COOLED BY THE STILL CHILLY LAKE ASHORE
SUNDAY. WHILE THE SURFACE RIDGE AXIS WILL BE MOVING OVER WI AND
WESTERN IL DURING MONDAY ALLOWING WINDS TO SLACKEN...A WEAK NE
SYNOPTIC FLOW WILL STILL BE IN PLACE AIDED BY A LAKE BREEZE.
THE FURTHER EASTWARD PROGRESS OF THE UPPER TROUGH IS TO BE SLOW AS A
CLOSED LOW TO FORM OVER SOUTHERN HUDSON BAY/NORTHERN ONTARIO IS
PROGGED TO BE DROP SOUTH...THEN SOUTHEAST AND EAST OVER ONTARIO
SATURDAY NIGHT THROUGH MONDAY NIGHT. AS THE UPPER TROUGH/LOW MOVES
FURTHER EAST A WEAK UPPER RIDGE WILL MOVE OVER THE REGION TUESDAY AS
ANOTHER UPPER LOW MOVES EAST OVER THE FAR SOUTHERN CANADIAN
PRAIRIE/FAR NORTHERN PLAINS. THIS WILL ALLOW A BIT OF MODERATION IN
TEMPERATURES TUESDAY AND WEDNESDAY AS EAST-SOUTHEAST WINDS BECOMES
SOUTHEASTERLY AND INCREASING THOUGH THIS LOW LEVEL FLOW WILL KEEP
THE IL SHORE...ESPECIALLY THE FAR NORTHERN PART....STILL CHILLY.
INLAND AREAS SHOULD PEAK IN THE UPPER 60S AND LOWER 70S TUESDAY...
AND A COUPLE DEGREES WARMER WEDNESDAY. WITH CONTINUED WARM AIR
ADVECTION AHEAD OF THE APPROACHING UPPER LOW/TROUGH THE WARMING
TREND WILL CONTINUE THURSDAY WITH MOST LOCATIONS REACHING THE MID
AND UPPER 70S THOUGH THERE WILL STILL BE AN EASTERLY COMPONENT TO
THE LOW LEVEL FLOW TO KEEP THE IL SHORELINE IN THE 60S.
TRS
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 20Z...
* ONGOING SCATTERED CONVECTION CONTINUING THROUGH THE EVENING AND
OVERNIGHT.
* COVERAGE OF TSTMS GRADUALLY INCREASING THROUGH REMAINDER OF
AFTERNOON.
* INDIVIDUAL STORMS PULSING UP AND DOWN HAVE POTENTIAL TO PRODUCE
SURFACE WIND GUSTS TO 50 KTS.
ED F
//DISCUSSION...UPDATED 18Z...
AN ACTIVE PERIOD IS EXPECTED WITH SEVERAL BOUTS OF THUNDERSTORMS
POSSIBLE AND GUSTY SOUTHERLY WINDS.
SYNOPTICALLY...AREA OF LOW PRESSURE LIES OVER THE NORTHERN PLAIN AND
WILL GRADUALLY SHIFT NORTHEAST THROUGH THE TAF PERIOD. NORTHERN
ILLINOIS LIES IN A TIGHT SOUTHERLY GRADIENT WITH WINDS GUSTING TO
AROUND 30 KT ALREADY EARLY THIS AFTERNOON AND EXPECTED TO PERSIST
THROUGH THE DAY. WINDS MAY TAPER SOME WITH SUNSET...THEN ARE
EXPECTED TO BECOME GUSTY AGAIN FRIDAY...THOUGH NOT QUITE AS STRONG
AS TODAY.
SEVERAL ROUNDS OF THUNDERSTORMS ARE POSSIBLE...WITH THE DETAILS
STILL A BIT MURKY. FIRST ROUND IS ALREADY STARTING TO TAKE SHAPE
THIS AFTERNOON AS STRONG INSTABILITY HAS DEVELOPED OVER THE AREA
WITH CONVECTION ALREADY DEVELOPING DOWNSTATE AHEAD OF A NEGATIVELY
TILTED TROUGH LIFTING ACROSS THE MID MISSISSIPPI VALLEY. THIS WAVE
WILL CONTINUE NORTHEAST INTO NORTHERN ILLINOIS MID AFTERNOON WITH
SCATTERED STRONG TO SEVERE THUNDERSTORMS EXPECTED OVER THE AREA.
WITH NO SIGNIFICANT LOW LEVEL BOUNDARIES OR FOCUSING MECHANISMS...IT
WILL BE HARD TO IMPOSSIBLE TO PINPOINT EXACTLY WHERE THUNDERSTORMS
WILL DEVELOP...THOUGH THE BEST INSTABILITY HAS SET UP JUST WEST OF
THE CHICAGO TERMINALS. THEN THIS EVENING...NUMEROUS CONVECTIVE
ALLOWING MODELS ARE INDICATING THAT A SECOND ROUND OF CONVECTION
WILL CONGEAL INTO A LINE OFF TO OUR WEST WITH THE DEVELOPMENT OF A
MODERATE TO STRONG LOW LEVEL JET ALONG THE MISSISSIPPI RIVER VALLEY.
THIS LINE IS EXPECTED TO RACE EAST LATE THIS EVENING OR EARLY
OVERNIGHT. FINALLY...WITH SIMILAR CONDITIONS IN PLACE
TOMORROW...WILL BE LOOKING AT MUCH OF THE SAME CONCERNS FRIDAY WITH
RESPECT TO PERIODIC CONVECTIVE CHANCES.
BMD
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
* HIGH CONFIDENCE IN TSTMS CONTINUING THROUGH THE EVENING WITH
GENERAL INCREASING TREND IN COVERAGE.
* LOW CONFIDENCE IN TIMING OF ANY SPECIFIC TSTM CELLS AT SPECIFIC
TERMINALS.
* MEDIUM CONFIDENCE IN LINE OF TSTMS IMPACTING TERMINALS LATE
THIS EVENING.
* MEDIUM CONFIDENCE IN ADDITIONAL TSTMS FRIDAY...LOW CONFIDENCE
IN TIMING.
* MEDIUM TO HIGH CONFIDENCE IN WIND TRENDS.
ED F
//OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z...
* FRIDAY THROUGH SATURDAY...PERIODS OF TSRA/SHRA.
POSSIBLE WITH MVFR CIGS/VIS.
* SUNDAY...CHANCE OF SHRA EARLY...OTRW...VFR.
* MONDAY THROUGH EARLY TUESDAY...VFR. WX NIL.
* LATE TUESDAY THROUGH WEDNESDAY...CHANCE TSRA/SHRA.
KREIN
&&
.MARINE...
1259 PM CDT
THE SHORT TERM OF THE MARINE FORECAST HAS A SMALL CRAFT ADVISORY FOR
STRONG WINDS ACROSS THE ILLINOIS AND NORTHWEST INDIANA NEARSHORE
WATERS.
ACROSS THE OPEN WATERS OF THE LAKE...MAINLY THE NORTHERN THIRD OF
THE LAKE...AREAS OF DENSE FOG CONTINUE.
VERY WARM/MOIST AIR CONTINUES TO SLIDE NORTH ACROSS THE LAKE...AND
WITH THE MUCH COOLER LAKE SURFACE WATER...HAS RESULTED IN AREAS OF
DENSE FOG PERSISTING. IT DOES APPEAR BASED ON LATEST VISIBLE IMAGERY
THAT THE FOG HAS REMAINED FOCUSED ACROSS THE NORTHERN THIRD OF THE
LAKE. OBS HAVE CONTINUED TO SHOW INCREASING GUSTS...WITH SPEEDS
GENERALLY AROUND 20-25KT ACROSS THE SOUTHERN HALF OF THE LAKE.
FURTHER NORTH IT APPEARS THE WINDS ARE SLIGHTLY LESS...WITH SPEEDS
GENERALLY IN THE 15-25KT.
THE TROUGH OF LOW PRESSURE REMAINS CENTERED ACROSS THE CENTRAL
PLAINS...WITH A WEAK LOW PRESSURE LIFTING NORTH INTO THE NORTHERN
PLAINS. AN ASSOCIATED WARM FRONT EXTENDS EAST THROUGH THE UPPER
GREAT LAKES REGION. WITH THE POSITION OF THE LOW PRESSURE AND THE
PERSISTING RIDGE OF HIGH PRESSURE ACROSS THE SOUTHEASTERN UNITED
STATES...THE WIND FLOW WILL REMAIN SOUTHERLY ACROSS THE LAKE. AT
TIMES THROUGH EARLY THIS EVENING GUSTS MAY APPROACH 30 KT...MAINLY
FOR THE SOUTHERN PORTIONS OF THE LAKE INCLUDING THE NEARSHORE
WATERS. AS A RESULT WILL MAINTAIN THE CURRENT SMALL CRAFT ADVISORY
THAT IS IN EFFECT.
THE TROUGH OF LOW PRESSURE POSITIONED OVER THE CENTRAL PLAINS WILL
SLOWLY PUSH EAST...WITH A LOW PRESSURE APPROACHING THE WESTERN GREAT
LAKES SAT MIDDAY. THE RECENT FORECAST TRENDS HAVE BEEN TO SLOW THE
ARRIVAL OF THIS SYSTEM...THUS IT IS POSSIBLE THAT THE MAIN LOW
PRESSURE MAY NOT ARRIVE UNTIL CLOSER TO SAT NIGHT. THEN AN
ASSOCIATED COLD FRONT WILL WILL PUSH EAST ACROSS THE LAKE OVERNIGHT
SAT INTO SUN. WINDS AT THAT POINT WILL TURN WESTERLY THEN NORTHERLY
WITH MUCH COOLER AIR FLOWING OVER THE LAKE.
BEACHLER
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...FLASH FLOOD WATCH...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-ILZ010-
ILZ011-ILZ012-ILZ013-ILZ014-ILZ019-ILZ020-ILZ021-ILZ022-
ILZ023-ILZ032-ILZ033-ILZ039 UNTIL 7 PM SATURDAY.
IN...FLASH FLOOD WATCH...INZ001-INZ002-INZ010-INZ011-INZ019 UNTIL 7
PM SATURDAY.
LM...DENSE FOG ADVISORY...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565
UNTIL 7 AM FRIDAY.
SMALL CRAFT ADVISORY...NEARSHORE WATERS
UNTIL 9 PM THURSDAY.
&&
$$
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
401 PM CDT THU MAY 30 2013
.DISCUSSION...
400 PM CDT
MAIN FORECAST CONCERNS REMAIN TIED TO THE ACTIVE WEATHER PATTERN
EXPECTED THROUGH THE START OF THE WEEKEND...WITH ROUNDS OF HEAVY
RAINFALL LIKELY AS WELL AS CONTINUED CHANCES FOR SEVERE WEATHER.
HAVE NOT EXPANDED THE FFA WATCH AT THIS TIME WITH MORE WIDESPREAD
HEAVY RAINFALL AND FLOODING NOT APPEARING LIKELY UNTIL LATER
FRIDAY AFTERNOON INTO FRIDAY NIGHT. THIS IS NOT TO SAY THAT
LOCALIZED FLOODING COULD NOT OCCUR WITH ANY POSSIBLE STRONG
THUNDERSTORMS TONIGHT. A MORE LIKELY SCENARIO AT THIS TIME IS WITH
THE CURRENT SCATTERED DEVELOPMENT TO BE REPLACED WITH A MORE
PROGRESSIVE AREA OF THUNDERSTORMS.
CURRENT ISOLATED TO SCATTERED ACTIVITY ACROSS THE CWA WILL
CONTINUE TO INCREASE IN COVERAGE THIS EVENING...AS LARGE SCALE
FORCING INCREASES WITH THE APPROACH A FAIRLY STOUT MID LEVEL WAVE
PROPAGATING NORTH THROUGH CENTRAL ILLINOIS. AREAS WHICH CONTINUE
TO BE FAVORED ARE LOCATIONS ALONG AND WEST OF A LINE FROM CRYSTAL
LAKE SOUTH TO GIBSON CITY IN ILLINOIS. LATEST RAP ANALYSIS SHOWS
MODERATE INSTABILITY IN PLACE WITH MLCAPE AROUND 2000 J/KG...AND
WITH MID/LOW LEVEL LAPSE RATES EXPECTED TO ONLY INCREASE OVER THE
NEXT COUPLE OF HOURS. THIS INCREASING FORCING AND INSTABILITY WILL
AID FURTHER DEVELOPMENT/EXPANSION OF CURRENT ACTIVITY ONGOING
ACROSS THE WESTERN HALF OF THE CWA. DEEP LAYER SHEAR REMAINS
MEAGER AT 25-30KT PRIMARILY OVER THE WESTERN CWA WHILE 0-1KM SHEAR
ALSO REMAINS HIGHEST ALONG OR JUST WEST OF THE CWA...ESPECIALLY
GOING INTO WESTERN ILLINOIS AND EASTERN IOWA.
HOWEVER...SHORT TERM GUIDANCE CONTINUES TO SHOW AN INCREASE IN
BOTH DEEP LAYER SHEAR AND LOW LEVEL SHEAR ACROSS THE CURRENT WATCH
AREA THROUGH THE REMAINDER OF THE AFTERNOON. THIS WILL HELP FOR
MORE ORGANIZED AND LONGER LIVED DEVELOPMENT ACROSS THE WESTERN
CWA...LEAVING THE THREAT OF HAIL/DAMAGING WINDS AS WELL AS
POSSIBLE TORNADOES. ALTHOUGH MORE ORGANIZED DEVELOPMENT IS MORE
LIKELY FOR THE WESTERN HALF OF THE CWA...SHORT TERM GUIDANCE IS
HINTING AT A SLIGHT INCREASE IN DEEP LAYER SHEAR MORE TOWARDS FAR
NORTHEAST ILLINOIS. THIS SLIGHT INCREASE COINCIDING WITH THE
CURRENT CAPE IN PLACE...COULD FAVOR SOME ISOLATED STRONGER
DEVELOPMENT IN THAT LOCATION IN THE NEXT COUPLE OF HOURS. WILL
NEED CONTINUE TO MONITOR DEVELOPMENT IN THAT LOCATION...WHICH
WOULD INCLUDE THE CITY OF CHICAGO/METRO AREA LATE THIS AFTERNOON
INTO THE EARLY EVENING...AS I COULD EASILY FORESEE AN UPSCALE IN
GROWTH IN BOTH INTENSITY AND COVERAGE.
EVEN IF THAT DOES NOT MATERIALIZE THROUGH LATE THIS
AFTERNOON...CONTINUE TO MONITOR A LARGER LINE OF THUNDERSTORMS
SITUATED FROM SOUTHERN IOWA SOUTH INTO MISSOURI. THIS LINE IS TIED
MORE CLOSELY TO FAIRLY STRONG MID LEVEL WAVE LIFTING NORTHEAST OUT
KANSAS AND ATTENDANT SURFACE TROUGH/BOUNDARY FROM IOWA INTO
MISSOURI. ALL GUIDANCE IS SHOWING THIS LINE OF THUNDERSTORMS
WILL INCREASE IN INTENSITY OVER THE NEXT COUPLE OF HOURS...WHICH
WOULD MAKE SENSE AS THIS LINE OF THUNDERSTORMS MOVES FURTHER
EAST/NORTHEAST INTO A MORE UNSTABLE ENVIRONMENT. STRONG FORCING
OWING TO LARGE SCALE SUPPORT AND LOW/MID LEVEL CONVERGENCE SHOULD
AID IN THIS LINE OF THUNDERSTORMS FURTHER BLOSSOMING AS IT MOVES
TOWARDS THE WESTERN ILLINOIS...ESPECIALLY AS DEEP LAYER SHEAR IS
ALSO INCREASING.
THERE IS STILL SOME UNCERTAINTY AS TO THE WHOLE EVOLUTION OF THIS
LINE OF THUNDERSTORMS AS IT WORKS ITS WAY TOWARDS NORTHERN
ILLINOIS THIS EVENING...MAINLY IN THE STRENGTH OF THIS COMPLEX AND
POTENTIAL SEVERE THREAT. ALTHOUGH THERE WILL BE SOME SLIGHT
DIMINISHING TREND WITH THE CURRENT INSTABILITY IN PLACE...FEEL
THAT IT WILL MORE THAN SUFFICE TO HELP KEEP THIS LINE SHIFTING
EAST. ALSO...SHORT TERM GUIDANCE IS INDICATING THAT 0-3KM BULK
SHEAR WILL INCREASE TOWARDS THE 00Z TIME FRAME THIS
EVENING...WHICH WOULD ACT TO HELP FOR ORGANIZATION AND INCREASE IN
THREAT FOR LINEAR STRUCTURES/STRONG DAMAGING WINDS. SO HAVE
TRENDED MORE PESSIMISTIC...WITH THINKING THAT THIS LINE AND STRONG
DAMAGING WINDS COULD MOVE ACROSS NORTHERN ILLINOIS THIS EVENING.
HAVE ALSO TRENDED MORE TOWARDS THE HRRR...WITH SYSTEM TIMING
THINKING THAT IT SHOULD BE KNOCKING ON THE WESTERN CWA DOORSTEPS
BY 00-01Z AND THEN CONTINUE EAST TOWARDS NORTHEAST ILLINOIS
THROUGH THE SEVERAL HOURS THERE AFTER. BEYOND THAT TIME
FRAME...CONFIDENCE LOWERS WITH REGARDS TO THE STRENGTH OF THIS
SYSTEM. NONETHELESS...HEAVY RAINFALL AND FLASH FLOODING COULD
BECOME ISSUES OVERNIGHT TONIGHT ESPECIALLY AS PWATS ARE AT OR JUST
ABOVE 1.7 INCHES AND 850MB DEW POINTS REMAIN RATHER HIGH.
THUNDERSTORM COMPLEX IS THEN EXPECTED TO SHIFT EAST OF THE CWA BY
EARLY FRIDAY MORNING...WITH A DRYING TREND EXPECTED DURING THAT
TIME FRAME. THIS SHOULD NOT LAST TOO LONG WITH DRY CONDITIONS ONLY
EXPECTED THROUGH MID DAY AS ATTENTION QUICKLY SHIFTS BACK WEST
WITH THE APPROACH OF ANOTHER STRONG MID LEVEL WAVE EJECTING OUT OF
THE CENTRAL PLAINS. YET AGAIN...A SEVERE THREAT WILL BE IN PLACE
ON FRIDAY WITH GROWING CONCERNS OF MORE POTENTIAL FLOODING FROM
THIS POINT ON...INTO FRIDAY NIGHT AND SATURDAY. THE SEVERE THREAT
WILL LIKELY AFFECT THE ENTIRE CWA ON FRIDAY AND WITH CLEARING
ANTICIPATED FRIDAY MORNING...INSTABILITY IS EXPECTED TO RAPIDLY
INCREASE BY LATE MORNING WITH MODERATE TO STRONG INSTABILITY
LIKELY IN PLACE ACROSS THE CWA. STRONG DEEP LAYER SHEAR IN UPWARDS
OF 50-60KT WILL EASILY SUPPORT WIDESPREAD ORGANIZED DEVELOPMENT AS
SOON AS EARLY AFTERNOON ON FRIDAY. STRONG DAMAGING WINDS AND HAIL
ARE THE MAIN THREAT...BUT WITH SREF GUIDANCE INDICATING ELEMENTS
CORRESPONDING TO SUPERCELLULAR STRUCTURES OR ROTATING
THUNDERSTORMS COULD COME TOGETHER ACROSS THE CWA. WILL NEED TO
CONTINUE TO MONITOR THIS TIME FRAME AS WELL...AS WIDESPREAD SEVERE
IS APPEARING LIKELY ONCE AGAIN. GOING INTO FRIDAY NIGHT...HEAVY
RAINFALL APPEARS LIKELY WITH SEVERAL STRONG WAVES PROPAGATING
NORTHEAST ACROSS THE CWA PROVIDING CONTINUED DEVELOPMENT AS WELL
AS A STRONG LLJ ORIENTED TOWARDS NORTHEAST ILLINOIS...PUMPING HIGH
THETAE AIR INTO THE REGION.
RODRIGUEZ
EXTENDED PERIOD...SUNDAY THROUGH THURSDAY...
BY DAYBREAK SUNDAY THE UPPER RIDGE IS TO HAVE PROGRESSED EASTWARD
TO OVER THE UPPER MIDWEST AND MID MS VALLEY WITH A SURFACE
TROUGH/SECONDARY COLD FRONT JUST TO THE NORTHWEST AND NORTH OF THE
LOCAL FORECAST AREA. THIS TROUGH/FRONT IS PROGGED TO MOVE ACROSS ALL
OF THE FA DURING THE SUNDAY MORNING AS THE UPPER TROUGH CONTINUES ON
TO OVER THE UPPER GREAT LAKES AND LOWER OH VALLEY BY EVENING. UNTIL
THE TROUGH AXIS MOVES A BIT FURTHER EAST OF THE IMMEDIATE AREA THERE
WILL BE A LINGERING CHANCE OF SHOWERS DURING SUNDAY MORNING.
THE SECONDARY COLD FRONT WILL REINFORCE THE COLD AIR ADVECTION THAT
WILL HAVE STARTED TO OCCUR LATE SATURDAY AND SATURDAY NIGHT WITH THE
INITIAL COLD FRONT. BETWEEN THE PAIR OF FRONT 850HPA TEMPERATURES
ARE PROGGED TO FALL AROUND 10 DEGREES C FROM 18Z SATURDAY TO 00Z
MONDAY......DOWN TO AROUND +4 OR +5C. WITH COOL HIGH PRESSURE
BUILDING OVER THE AREA TEMPERATURES WILL BE COOL SUNDAY AND MONDAY
WITH HIGHS ONLY IN THE 60S...WITH LAKESIDE MAX TEMPERATURES LIKELY
TO ONLY BE IN THE 55-60F RANGE AS A LONG FETCH DOWN LAKE MICHIGAN
BRINGS AIR ADDITIONALLY COOLED BY THE STILL CHILLY LAKE ASHORE
SUNDAY. WHILE THE SURFACE RIDGE AXIS WILL BE MOVING OVER WI AND
WESTERN IL DURING MONDAY ALLOWING WINDS TO SLACKEN...A WEAK NE
SYNOPTIC FLOW WILL STILL BE IN PLACE AIDED BY A LAKE BREEZE.
THE FURTHER EASTWARD PROGRESS OF THE UPPER TROUGH IS TO BE SLOW AS A
CLOSED LOW TO FORM OVER SOUTHERN HUDSON BAY/NORTHERN ONTARIO IS
PROGGED TO BE DROP SOUTH...THEN SOUTHEAST AND EAST OVER ONTARIO
SATURDAY NIGHT THROUGH MONDAY NIGHT. AS THE UPPER TROUGH/LOW MOVES
FURTHER EAST A WEAK UPPER RIDGE WILL MOVE OVER THE REGION TUESDAY AS
ANOTHER UPPER LOW MOVES EAST OVER THE FAR SOUTHERN CANADIAN
PRAIRIE/FAR NORTHERN PLAINS. THIS WILL ALLOW A BIT OF MODERATION IN
TEMPERATURES TUESDAY AND WEDNESDAY AS EAST-SOUTHEAST WINDS BECOMES
SOUTHEASTERLY AND INCREASING THOUGH THIS LOW LEVEL FLOW WILL KEEP
THE IL SHORE...ESPECIALLY THE FAR NORTHERN PART....STILL CHILLY.
INLAND AREAS SHOULD PEAK IN THE UPPER 60S AND LOWER 70S TUESDAY...
AND A COUPLE DEGREES WARMER WEDNESDAY. WITH CONTINUED WARM AIR
ADVECTION AHEAD OF THE APPROACHING UPPER LOW/TROUGH THE WARMING
TREND WILL CONTINUE THURSDAY WITH MOST LOCATIONS REACHING THE MID
AND UPPER 70S THOUGH THERE WILL STILL BE AN EASTERLY COMPONENT TO
THE LOW LEVEL FLOW TO KEEP THE IL SHORELINE IN THE 60S.
TRS
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 20Z...
* ONGOING SCATTERED CONVECTION CONTINUING THROUGH THE EVENING AND
OVERNIGHT.
* COVERAGE OF TSTMS GRADUALLY INCREASING THROUGH REMAINDER OF
AFTERNOON.
* INDIVIDUAL STORMS PULSING UP AND DOWN HAVE POTENTIAL TO PRODUCE
SURFACE WIND GUSTS TO 50 KTS.
ED F
//DISCUSSION...UPDATED 18Z...
AN ACTIVE PERIOD IS EXPECTED WITH SEVERAL BOUTS OF THUNDERSTORMS
POSSIBLE AND GUSTY SOUTHERLY WINDS.
SYNOPTICALLY...AREA OF LOW PRESSURE LIES OVER THE NORTHERN PLAIN AND
WILL GRADUALLY SHIFT NORTHEAST THROUGH THE TAF PERIOD. NORTHERN
ILLINOIS LIES IN A TIGHT SOUTHERLY GRADIENT WITH WINDS GUSTING TO
AROUND 30 KT ALREADY EARLY THIS AFTERNOON AND EXPECTED TO PERSIST
THROUGH THE DAY. WINDS MAY TAPER SOME WITH SUNSET...THEN ARE
EXPECTED TO BECOME GUSTY AGAIN FRIDAY...THOUGH NOT QUITE AS STRONG
AS TODAY.
SEVERAL ROUNDS OF THUNDERSTORMS ARE POSSIBLE...WITH THE DETAILS
STILL A BIT MURKY. FIRST ROUND IS ALREADY STARTING TO TAKE SHAPE
THIS AFTERNOON AS STRONG INSTABILITY HAS DEVELOPED OVER THE AREA
WITH CONVECTION ALREADY DEVELOPING DOWNSTATE AHEAD OF A NEGATIVELY
TILTED TROUGH LIFTING ACROSS THE MID MISSISSIPPI VALLEY. THIS WAVE
WILL CONTINUE NORTHEAST INTO NORTHERN ILLINOIS MID AFTERNOON WITH
SCATTERED STRONG TO SEVERE THUNDERSTORMS EXPECTED OVER THE AREA.
WITH NO SIGNIFICANT LOW LEVEL BOUNDARIES OR FOCUSING MECHANISMS...IT
WILL BE HARD TO IMPOSSIBLE TO PINPOINT EXACTLY WHERE THUNDERSTORMS
WILL DEVELOP...THOUGH THE BEST INSTABILITY HAS SET UP JUST WEST OF
THE CHICAGO TERMINALS. THEN THIS EVENING...NUMEROUS CONVECTIVE
ALLOWING MODELS ARE INDICATING THAT A SECOND ROUND OF CONVECTION
WILL CONGEAL INTO A LINE OFF TO OUR WEST WITH THE DEVELOPMENT OF A
MODERATE TO STRONG LOW LEVEL JET ALONG THE MISSISSIPPI RIVER VALLEY.
THIS LINE IS EXPECTED TO RACE EAST LATE THIS EVENING OR EARLY
OVERNIGHT. FINALLY...WITH SIMILAR CONDITIONS IN PLACE
TOMORROW...WILL BE LOOKING AT MUCH OF THE SAME CONCERNS FRIDAY WITH
RESPECT TO PERIODIC CONVECTIVE CHANCES.
BMD
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
* HIGH CONFIDENCE IN TSTMS CONTINUING THROUGH THE EVENING WITH
GENERAL INCREASING TREND IN COVERAGE.
* LOW CONFIDENCE IN TIMING OF ANY SPECIFIC TSTM CELLS AT SPECIFIC
TERMINALS.
* MEDIUM CONFIDENCE IN LINE OF TSTMS IMPACTING TERMINALS LATE
THIS EVENING.
* MEDIUM CONFIDENCE IN ADDITIONAL TSTMS FRIDAY...LOW CONFIDENCE
IN TIMING.
* MEDIUM TO HIGH CONFIDENCE IN WIND TRENDS.
ED F
//OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z...
* FRIDAY THROUGH SATURDAY...PERIODS OF TSRA/SHRA.
POSSIBLE WITH MVFR CIGS/VIS.
* SUNDAY...CHANCE OF SHRA EARLY...OTRW...VFR.
* MONDAY THROUGH EARLY TUESDAY...VFR. WX NIL.
* LATE TUESDAY THROUGH WEDNESDAY...CHANCE TSRA/SHRA.
KREIN
&&
.MARINE...
1259 PM CDT
THE SHORT TERM OF THE MARINE FORECAST HAS A SMALL CRAFT ADVISORY FOR
STRONG WINDS ACROSS THE ILLINOIS AND NORTHWEST INDIANA NEARSHORE
WATERS.
ACROSS THE OPEN WATERS OF THE LAKE...MAINLY THE NORTHERN THIRD OF
THE LAKE...AREAS OF DENSE FOG CONTINUE.
VERY WARM/MOIST AIR CONTINUES TO SLIDE NORTH ACROSS THE LAKE...AND
WITH THE MUCH COOLER LAKE SURFACE WATER...HAS RESULTED IN AREAS OF
DENSE FOG PERSISTING. IT DOES APPEAR BASED ON LATEST VISIBLE IMAGERY
THAT THE FOG HAS REMAINED FOCUSED ACROSS THE NORTHERN THIRD OF THE
LAKE. OBS HAVE CONTINUED TO SHOW INCREASING GUSTS...WITH SPEEDS
GENERALLY AROUND 20-25KT ACROSS THE SOUTHERN HALF OF THE LAKE.
FURTHER NORTH IT APPEARS THE WINDS ARE SLIGHTLY LESS...WITH SPEEDS
GENERALLY IN THE 15-25KT.
THE TROUGH OF LOW PRESSURE REMAINS CENTERED ACROSS THE CENTRAL
PLAINS...WITH A WEAK LOW PRESSURE LIFTING NORTH INTO THE NORTHERN
PLAINS. AN ASSOCIATED WARM FRONT EXTENDS EAST THROUGH THE UPPER
GREAT LAKES REGION. WITH THE POSITION OF THE LOW PRESSURE AND THE
PERSISTING RIDGE OF HIGH PRESSURE ACROSS THE SOUTHEASTERN UNITED
STATES...THE WIND FLOW WILL REMAIN SOUTHERLY ACROSS THE LAKE. AT
TIMES THROUGH EARLY THIS EVENING GUSTS MAY APPROACH 30 KT...MAINLY
FOR THE SOUTHERN PORTIONS OF THE LAKE INCLUDING THE NEARSHORE
WATERS. AS A RESULT WILL MAINTAIN THE CURRENT SMALL CRAFT ADVISORY
THAT IS IN EFFECT.
THE TROUGH OF LOW PRESSURE POSITIONED OVER THE CENTRAL PLAINS WILL
SLOWLY PUSH EAST...WITH A LOW PRESSURE APPROACHING THE WESTERN GREAT
LAKES SAT MIDDAY. THE RECENT FORECAST TRENDS HAVE BEEN TO SLOW THE
ARRIVAL OF THIS SYSTEM...THUS IT IS POSSIBLE THAT THE MAIN LOW
PRESSURE MAY NOT ARRIVE UNTIL CLOSER TO SAT NIGHT. THEN AN
ASSOCIATED COLD FRONT WILL WILL PUSH EAST ACROSS THE LAKE OVERNIGHT
SAT INTO SUN. WINDS AT THAT POINT WILL TURN WESTERLY THEN NORTHERLY
WITH MUCH COOLER AIR FLOWING OVER THE LAKE.
BEACHLER
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...FLASH FLOOD WATCH...ILZ019-ILZ032...7 PM THURSDAY TO 7 PM
SATURDAY.
IN...NONE.
LM...DENSE FOG ADVISORY...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565
UNTIL 7 AM FRIDAY.
SMALL CRAFT ADVISORY...NEARSHORE WATERS
UNTIL 9 PM THURSDAY.
&&
$$
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
329 PM CDT THU MAY 30 2013
.DISCUSSION...
326 PM CDT
MAIN FORECAST CONCERNS REMAIN TIED TO THE ACTIVE WEATHER PATTERN
EXPECTED THROUGH THE START OF THE WEEKEND...WITH ROUNDS OF HEAVY
RAINFALL LIKELY AS WELL AS CONTINUED CHANCES FOR SEVERE WEATHER.
HAVE NOT EXPANDED THE FFA WATCH AT THIS TIME WITH MORE WIDESPREAD
HEAVY RAINFALL AND FLOODING NOT APPEARING LIKELY UNTIL LATER
FRIDAY AFTERNOON INTO FRIDAY NIGHT. THIS IS NOT TO SAY THAT
LOCALIZED FLOODING COULD NOT OCCUR WITH ANY POSSIBLE STRONG
THUNDERSTORMS TONIGHT. A MORE LIKELY SCENARIO AT THIS TIME IS WITH
THE CURRENT SCATTERED DEVELOPMENT TO BE REPLACED WITH A MORE
PROGRESSIVE AREA OF THUNDERSTORMS.
CURRENT ISOLATED TO SCATTERED ACTIVITY ACROSS THE CWA WILL
CONTINUE TO INCREASE IN COVERAGE THIS EVENING...AS LARGE SCALE
FORCING INCREASES WITH THE APPROACH A FAIRLY STOUT MID LEVEL WAVE
PROPAGATING NORTH THROUGH CENTRAL ILLINOIS. AREAS WHICH CONTINUE
TO BE FAVORED ARE LOCATIONS ALONG AND WEST OF A LINE FROM CRYSTAL
LAKE SOUTH TO GIBSON CITY IN ILLINOIS. LATEST RAP ANALYSIS SHOWS
MODERATE INSTABILITY IN PLACE WITH MLCAPE AROUND 2000 J/KG...AND
WITH MID/LOW LEVEL LAPSE RATES EXPECTED TO ONLY INCREASE OVER THE
NEXT COUPLE OF HOURS. THIS INCREASING FORCING AND INSTABILITY WILL
AID FURTHER DEVELOPMENT/EXPANSION OF CURRENT ACTIVITY ONGOING
ACROSS THE WESTERN HALF OF THE CWA. DEEP LAYER SHEAR REMAINS
MEAGER AT 25-30KT PRIMARILY OVER THE WESTERN CWA WHILE 0-1KM SHEAR
ALSO REMAINS HIGHEST ALONG OR JUST WEST OF THE CWA...ESPECIALLY
GOING INTO WESTERN ILLINOIS AND EASTERN IOWA.
HOWEVER...SHORT TERM GUIDANCE CONTINUES TO SHOW AN INCREASE IN
BOTH DEEP LAYER SHEAR AND LOW LEVEL SHEAR ACROSS THE CURRENT WATCH
AREA THROUGH THE REMAINDER OF THE AFTERNOON. THIS WILL HELP FOR
MORE ORGANIZED AND LONGER LIVED DEVELOPMENT ACROSS THE WESTERN
CWA...LEAVING THE THREAT OF HAIL/DAMAGING WINDS AS WELL AS
POSSIBLE TORNADOES. ALTHOUGH MORE ORGANIZED DEVELOPMENT IS MORE
LIKELY FOR THE WESTERN HALF OF THE CWA...SHORT TERM GUIDANCE IS
HINTING AT A SLIGHT INCREASE IN DEEP LAYER SHEAR MORE TOWARDS FAR
NORTHEAST ILLINOIS. THIS SLIGHT INCREASE COINCIDING WITH THE
CURRENT CAPE IN PLACE...COULD FAVOR SOME ISOLATED STRONGER
DEVELOPMENT IN THAT LOCATION IN THE NEXT COUPLE OF HOURS. WILL
NEED CONTINUE TO MONITOR DEVELOPMENT IN THAT LOCATION...WHICH
WOULD INCLUDE THE CITY OF CHICAGO/METRO AREA LATE THIS AFTERNOON
INTO THE EARLY EVENING...AS I COULD EASILY FORESEE AN UPSCALE IN
GROWTH IN BOTH INTENSITY AND COVERAGE.
EVEN IF THAT DOES NOT MATERIALIZE THROUGH LATE THIS
AFTERNOON...CONTINUE TO MONITOR A LARGER LINE OF THUNDERSTORMS
SITUATED FROM SOUTHERN IOWA SOUTH INTO MISSOURI. THIS LINE IS TIED
MORE CLOSELY TO FAIRLY STRONG MID LEVEL WAVE LIFTING NORTHEAST OUT
KANSAS AND ATTENDANT SURFACE TROUGH/BOUNDARY FROM IOWA INTO
MISSOURI. ALL GUIDANCE IS SHOWING THIS LINE OF THUNDERSTORMS
WILL INCREASE IN INTENSITY OVER THE NEXT COUPLE OF HOURS...WHICH
WOULD MAKE SENSE AS THIS LINE OF THUNDERSTORMS MOVES FURTHER
EAST/NORTHEAST INTO A MORE UNSTABLE ENVIRONMENT. STRONG FORCING
OWING TO LARGE SCALE SUPPORT AND LOW/MID LEVEL CONVERGENCE SHOULD
AID IN THIS LINE OF THUNDERSTORMS FURTHER BLOSSOMING AS IT MOVES
TOWARDS THE WESTERN ILLINOIS...ESPECIALLY AS DEEP LAYER SHEAR IS
ALSO INCREASING.
THERE IS STILL SOME UNCERTAINTY AS TO THE WHOLE EVOLUTION OF THIS
LINE OF THUNDERSTORMS AS IT WORKS ITS WAY TOWARDS NORTHERN
ILLINOIS THIS EVENING...MAINLY IN THE STRENGTH OF THIS COMPLEX AND
POTENTIAL SEVERE THREAT. ALTHOUGH THERE WILL BE SOME SLIGHT
DIMINISHING TREND WITH THE CURRENT INSTABILITY IN PLACE...FEEL
THAT IT WILL MORE THAN SUFFICE TO HELP KEEP THIS LINE SHIFTING
EAST. ALSO...SHORT TERM GUIDANCE IS INDICATING THAT 0-3KM BULK
SHEAR WILL INCREASE TOWARDS THE 00Z TIME FRAME THIS
EVENING...WHICH WOULD ACT TO HELP FOR ORGANIZATION AND INCREASE IN
THREAT FOR LINEAR STRUCTURES/STRONG DAMAGING WINDS. SO HAVE
TRENDED MORE PESSIMISTIC...WITH THINKING THAT THIS LINE AND STRONG
DAMAGING WINDS COULD MOVE ACROSS NORTHERN ILLINOIS THIS EVENING.
HAVE ALSO TRENDED MORE TOWARDS THE HRRR...WITH SYSTEM TIMING
THINKING THAT IT SHOULD BE KNOCKING ON THE WESTERN CWA DOORSTEPS
BY 00-01Z AND THEN CONTINUE EAST TOWARDS NORTHEAST ILLINOIS
THROUGH THE SEVERAL HOURS THERE AFTER. BEYOND THAT TIME
FRAME...CONFIDENCE LOWERS WITH REGARDS TO THE STRENGTH OF THIS
SYSTEM. NONETHELESS...HEAVY RAINFALL AND FLASH FLOODING COULD
BECOME ISSUES OVERNIGHT TONIGHT ESPECIALLY AS PWATS ARE AT OR JUST
ABOVE 1.7 INCHES AND 850MB DEW POINTS REMAIN RATHER HIGH.
THUNDERSTORM COMPLEX IS THEN EXPECTED TO SHIFT EAST OF THE CWA BY
EARLY FRIDAY MORNING...WITH A DRYING TREND EXPECTED DURING THAT
TIME FRAME. THIS SHOULD NOT LAST TOO LONG WITH DRY CONDITIONS ONLY
EXPECTED THROUGH MID DAY AS ATTENTION QUICKLY SHIFTS BACK WEST
WITH THE APPROACH OF ANOTHER STRONG MID LEVEL WAVE EJECTING OUT OF
THE CENTRAL PLAINS. YET AGAIN...A SEVERE THREAT WILL BE IN PLACE
ON FRIDAY WITH GROWING CONCERNS OF MORE POTENTIAL FLOODING FROM
THIS POINT ON...INTO FRIDAY NIGHT AND SATURDAY. THE SEVERE THREAT
WILL LIKELY AFFECT THE ENTIRE CWA ON FRIDAY AND WITH CLEARING
ANTICIPATED FRIDAY MORNING...INSTABILITY IS EXPECTED TO RAPIDLY
INCREASE BY LATE MORNING WITH MODERATE TO STRONG INSTABILITY
LIKELY IN PLACE ACROSS THE CWA. STRONG DEEP LAYER SHEAR IN UPWARDS
OF 50-60KT WILL EASILY SUPPORT WIDESPREAD ORGANIZED DEVELOPMENT AS
SOON AS EARLY AFTERNOON ON FRIDAY. STRONG DAMAGING WINDS AND HAIL
ARE THE MAIN THREAT...BUT WITH SREF GUIDANCE INDICATING ELEMENTS
CORRESPONDING TO SUPERCELLULAR STRUCTURES OR ROTATING
THUNDERSTORMS COULD COME TOGETHER ACROSS THE CWA. WILL NEED TO
CONTINUE TO MONITOR THIS TIME FRAME AS WELL...AS WIDESPREAD SEVERE
IS APPEARING LIKELY ONCE AGAIN. GOING INTO FRIDAY NIGHT...HEAVY
RAINFALL APPEARS LIKELY WITH SEVERAL STRONG WAVES PROPAGATING
NORTHEAST ACROSS THE CWA PROVIDING CONTINUED DEVELOPMENT AS WELL
AS A STRONG LLJ ORIENTED TOWARDS NORTHEAST ILLINOIS...PUMPING HIGH
THETAE AIR INTO THE REGION.
RODRIGUEZ
EXTENDED...COMING SOON.
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 20Z...
* ONGOING SCATTERED CONVECTION CONTINUING THROUGH THE EVENING AND
OVERNIGHT.
* COVERAGE OF TSTMS GRADUALLY INCREASING THROUGH REMAINDER OF
AFTERNOON.
* INDIVIDUAL STORMS PULSING UP AND DOWN HAVE POTENTIAL TO PRODUCE
SURFACE WIND GUSTS TO 50 KTS.
ED F
//DISCUSSION...UPDATED 18Z...
AN ACTIVE PERIOD IS EXPECTED WITH SEVERAL BOUTS OF THUNDERSTORMS
POSSIBLE AND GUSTY SOUTHERLY WINDS.
SYNOPTICALLY...AREA OF LOW PRESSURE LIES OVER THE NORTHERN PLAIN AND
WILL GRADUALLY SHIFT NORTHEAST THROUGH THE TAF PERIOD. NORTHERN
ILLINOIS LIES IN A TIGHT SOUTHERLY GRADIENT WITH WINDS GUSTING TO
AROUND 30 KT ALREADY EARLY THIS AFTERNOON AND EXPECTED TO PERSIST
THROUGH THE DAY. WINDS MAY TAPER SOME WITH SUNSET...THEN ARE
EXPECTED TO BECOME GUSTY AGAIN FRIDAY...THOUGH NOT QUITE AS STRONG
AS TODAY.
SEVERAL ROUNDS OF THUNDERSTORMS ARE POSSIBLE...WITH THE DETAILS
STILL A BIT MURKY. FIRST ROUND IS ALREADY STARTING TO TAKE SHAPE
THIS AFTERNOON AS STRONG INSTABILITY HAS DEVELOPED OVER THE AREA
WITH CONVECTION ALREADY DEVELOPING DOWNSTATE AHEAD OF A NEGATIVELY
TILTED TROUGH LIFTING ACROSS THE MID MISSISSIPPI VALLEY. THIS WAVE
WILL CONTINUE NORTHEAST INTO NORTHERN ILLINOIS MID AFTERNOON WITH
SCATTERED STRONG TO SEVERE THUNDERSTORMS EXPECTED OVER THE AREA.
WITH NO SIGNIFICANT LOW LEVEL BOUNDARIES OR FOCUSING MECHANISMS...IT
WILL BE HARD TO IMPOSSIBLE TO PINPOINT EXACTLY WHERE THUNDERSTORMS
WILL DEVELOP...THOUGH THE BEST INSTABILITY HAS SET UP JUST WEST OF
THE CHICAGO TERMINALS. THEN THIS EVENING...NUMEROUS CONVECTIVE
ALLOWING MODELS ARE INDICATING THAT A SECOND ROUND OF CONVECTION
WILL CONGEAL INTO A LINE OFF TO OUR WEST WITH THE DEVELOPMENT OF A
MODERATE TO STRONG LOW LEVEL JET ALONG THE MISSISSIPPI RIVER VALLEY.
THIS LINE IS EXPECTED TO RACE EAST LATE THIS EVENING OR EARLY
OVERNIGHT. FINALLY...WITH SIMILAR CONDITIONS IN PLACE
TOMORROW...WILL BE LOOKING AT MUCH OF THE SAME CONCERNS FRIDAY WITH
RESPECT TO PERIODIC CONVECTIVE CHANCES.
BMD
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
* HIGH CONFIDENCE IN TSTMS CONTINUING THROUGH THE EVENING WITH
GENERAL INCREASING TREND IN COVERAGE.
* LOW CONFIDENCE IN TIMING OF ANY SPECIFIC TSTM CELLS AT SPECIFIC
TERMINALS.
* MEDIUM CONFIDENCE IN LINE OF TSTMS IMPACTING TERMINALS LATE
THIS EVENING.
* MEDIUM CONFIDENCE IN ADDITIONAL TSTMS FRIDAY...LOW CONFIDENCE
IN TIMING.
* MEDIUM TO HIGH CONFIDENCE IN WIND TRENDS.
ED F
//OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z...
* FRIDAY THROUGH SATURDAY...PERIODS OF TSRA/SHRA.
POSSIBLE WITH MVFR CIGS/VIS.
* SUNDAY...CHANCE OF SHRA EARLY...OTRW...VFR.
* MONDAY THROUGH EARLY TUESDAY...VFR. WX NIL.
* LATE TUESDAY THROUGH WEDNESDAY...CHANCE TSRA/SHRA.
KREIN
&&
.MARINE...
1259 PM CDT
THE SHORT TERM OF THE MARINE FORECAST HAS A SMALL CRAFT ADVISORY FOR
STRONG WINDS ACROSS THE ILLINOIS AND NORTHWEST INDIANA NEARSHORE
WATERS.
ACROSS THE OPEN WATERS OF THE LAKE...MAINLY THE NORTHERN THIRD OF
THE LAKE...AREAS OF DENSE FOG CONTINUE.
VERY WARM/MOIST AIR CONTINUES TO SLIDE NORTH ACROSS THE LAKE...AND
WITH THE MUCH COOLER LAKE SURFACE WATER...HAS RESULTED IN AREAS OF
DENSE FOG PERSISTING. IT DOES APPEAR BASED ON LATEST VISIBLE IMAGERY
THAT THE FOG HAS REMAINED FOCUSED ACROSS THE NORTHERN THIRD OF THE
LAKE. OBS HAVE CONTINUED TO SHOW INCREASING GUSTS...WITH SPEEDS
GENERALLY AROUND 20-25KT ACROSS THE SOUTHERN HALF OF THE LAKE.
FURTHER NORTH IT APPEARS THE WINDS ARE SLIGHTLY LESS...WITH SPEEDS
GENERALLY IN THE 15-25KT.
THE TROUGH OF LOW PRESSURE REMAINS CENTERED ACROSS THE CENTRAL
PLAINS...WITH A WEAK LOW PRESSURE LIFTING NORTH INTO THE NORTHERN
PLAINS. AN ASSOCIATED WARM FRONT EXTENDS EAST THROUGH THE UPPER
GREAT LAKES REGION. WITH THE POSITION OF THE LOW PRESSURE AND THE
PERSISTING RIDGE OF HIGH PRESSURE ACROSS THE SOUTHEASTERN UNITED
STATES...THE WIND FLOW WILL REMAIN SOUTHERLY ACROSS THE LAKE. AT
TIMES THROUGH EARLY THIS EVENING GUSTS MAY APPROACH 30 KT...MAINLY
FOR THE SOUTHERN PORTIONS OF THE LAKE INCLUDING THE NEARSHORE
WATERS. AS A RESULT WILL MAINTAIN THE CURRENT SMALL CRAFT ADVISORY
THAT IS IN EFFECT.
THE TROUGH OF LOW PRESSURE POSITIONED OVER THE CENTRAL PLAINS WILL
SLOWLY PUSH EAST...WITH A LOW PRESSURE APPROACHING THE WESTERN GREAT
LAKES SAT MIDDAY. THE RECENT FORECAST TRENDS HAVE BEEN TO SLOW THE
ARRIVAL OF THIS SYSTEM...THUS IT IS POSSIBLE THAT THE MAIN LOW
PRESSURE MAY NOT ARRIVE UNTIL CLOSER TO SAT NIGHT. THEN AN
ASSOCIATED COLD FRONT WILL WILL PUSH EAST ACROSS THE LAKE OVERNIGHT
SAT INTO SUN. WINDS AT THAT POINT WILL TURN WESTERLY THEN NORTHERLY
WITH MUCH COOLER AIR FLOWING OVER THE LAKE.
BEACHLER
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...FLASH FLOOD WATCH...ILZ019-ILZ032...7 PM THURSDAY TO 7 PM
SATURDAY.
IN...NONE.
LM...DENSE FOG ADVISORY...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565
UNTIL 7 AM FRIDAY.
SMALL CRAFT ADVISORY...NEARSHORE WATERS
UNTIL 9 PM THURSDAY.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
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WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
322 PM CDT THU MAY 30 2013
.MESOSCALE DISCUSSION...
309 PM CDT
SCATTERED THUNDERSTORMS CONTINUE TO FIRE ACROSS THE REGION. LACK OF
LOW LEVEL CONVERGENCE AND ANY CONVECTIVE INHIBITION ALONG WITH
INCREASING LARGE SCALE ASCENT AHEAD OF APPROACHING SHORT WAVE
EVIDENT ON WATER VAPOR IMAGERY MOVING INTO WESTERN ILLINOIS SHOULD
CONTINUE TO ALLOW THIS REGIME WITH STORMS GOING UP JUST ABOUT
ANYWHERE.
WIND PROFILERS SHOW A PRETTY TIGHT GRADIENT IN MID LEVEL FLOW WITH
PROFILERS SHOWING 55-60KT WINDS AT 6KM OVER WESTERN ILLINOIS INTO
IA/MO WITH ONLY ABOUT 40KT OF FLOW OVER OUR AREA. UNIDIRECTIONAL
NATURE OF THE FLOW IS MINIMIZING DEEP LAYER SHEAR OVER OUR EASTERN
CWA WITH ABOUT DEEP LAYER SHEAR ABOUT 20-30KT INCREASING TO AROUND
40KT WESTERN CWA. RAP SUGGESTS THAT THE STRONGER SHEAR WILL SPREAD
EASTWARD ACROSS THE CWA THIS EVENING.
LOW LEVEL SHEAR IS NOT OVERLY STRONG AT THIS TIME WITH WELL MIXED
BOUNDARY LAYER...HOWEVER T/TD SPREADS ARE IN THE NEIGHBORHOOD OF
10-15F SO LCL HEIGHTS ARE NOT THAT HIGH SUGGESTING AT LEAST SOME
LIMITED TORNADO THREAT FOR THE NEXT HOUR OR TWO. THIS WILL
PARTICULARLY BE THE CASE WITH ANY CELLS THAT ARE ABLE TO ACHIEVE
MORE DEVIANT RIGHTWARD MOTION AUGMENTING THE LOW LEVEL SHEAR.
LOW LEVEL SHEAR SHOULD INCREASE THIS EVENING WITH DEVELOPMENT OF LOW
LEVEL WIND MAXIMA...SO ASSUMING CONVECTION REMAINS CELLULAR AND
ROOTED IN THE BOUNDARY LAYER THEN TORNADO THREAT COULD INCREASE SOME
FOR A TIME EARLY THIS EVENING. IN THE NEXT HOUR OR TWO THINK THE
PRIMARY HAZARD WILL BE DMG WIND AND HAIL...WITH A SLIGHT TORNADO
THREAT MOSTLY OVER WESTERN CWA.
IZZI
&&
.DISCUSSION...
326 AM CDT
CONVECTIVE TRENDS AND ASSOCIATED HEAVY RAIN AND SEVERE WEATHER
THREAT REMAIN THE FOCUS OF THE FORECAST THIS PERIOD. UPPER AIR
ANALYSIS AND EARLY MORNING WATER VAPOR IMAGERY SHOW A MUCH MORE
AMPLIFIED PATTERN THAN LAST NIGHT WITH A BROAD RIDGE OVER THE
EASTERN THIRD OR SO OF THE COUNTRY WITH A RIDGE AXIS EXTENDING FROM
NORTHERN OHIO TO THE CANADIAN PRAIRIES. THE BASE OF A LONGWAVE
TROUGH IS POSITIONED OVER THE FAR SOUTHERN PLAINS WITH THE AXIS
EXTENDING NORTHWEST TO A CLOSED LOW SPINNING OFF THE BRITISH
COLUMBIA COAST. SEVERAL SHORTWAVES ARE EMBEDDED WITHIN THE
SOUTH-SOUTHWEST FLOW OVER THE CENTER OF THE COUNTRY. AT THE
SURFACE...ONE LOW PRESSURE AREA IS POSITIONED OVER SOUTH DAKOTA WITH
A SECOND OVER THE TX/OK PANHANDLE. A COLD FRONT IS STRETCHED BETWEEN
THESE TWO LOWS WITH A WARM FRONTAL BOUNDARY FROM SOUTH DAKOTA ACROSS
FAR NORTHERN LAKE MICHIGAN.
TODAY THROUGH FRIDAY...AN UPPER LEVEL LOW WILL CLOSE OFF OVER THE
WESTERN DAKOTAS TODAY AS THE MAIN LONGWAVE AXIS PIVOTS NORTHWARD
ACROSS THE CENTRAL/SOUTHERN PLAINS AND MID MISSISSIPPI RIVER VALLEY.
THIS WILL DEEPEN THE SURFACE LOW ACROSS THE DAKOTAS AND HELP PUSH
THE ATTENDANT COLD FRONT INTO FAR WESTERN MINNESOTA AND IOWA BY
EVENING. THERE ARE A RANGE OF POSSIBILITIES WITH REGARD TO
CONVECTIVE EVOLUTION INTO TONIGHT GIVEN THE UPPER FLOW PATTERN AND
PRESENCE OF NUMEROUS EMBEDDED WAVES. WATER VAPOR SHOWS THE LONGWAVE
TROUGH AXIS PIVOTING NORTHEASTWARD ACROSS TX/OK AS IT IS BEING
PUSHED BY A STRONG UPPER JET CORE ON ITS WESTERN FLANK. THE MAIN
TROUGH ITSELF IS THE MOST COHERENT FOCUS FOR CONVECTIVE
DEVELOPMENT...IN ADDITION TO THE NUMEROUS EMBEDDED WAVES. WITH THE
STEERING FLOW PRETTY SELY THIS MORNING...THIS WILL INITIALLY KEEP
ACTIVITY ON A TRAJECTORY WEST OF THE CWA BUT WITH THE MAIN LONGWAVE
TROUGH SHIFTING EASTWARD AS AN UPPER JET MAX PUSHES IT FROM THE WEST
THE MAIN CORRIDOR OF FLOW WILL TRANSLATE EASTWARD SPREADING
CONVECTIVE CHANCES FURTHER INTO THE AREA. CHANCES FOR STORMS WILL
THEREFORE INCREASE FROM WEST TO EAST THROUGH THE DAY...WITH MINIMAL
CHANCES THROUGH LATE MORNING THOUGH THERE IS SUGGESTION OF SOME
SCATTERED DEVELOPMENT THANKS TO A WEAK UPPER WAVE THAT AT THIS POINT
IS NOT REALLY WELL DEFINED ON SATELLITE AND ONLY GENERATING CLOUD
COVER WHICH IS MOVING NORTHWARD INTO SOUTHERN ILLINOIS. BEYOND THIS
MORNING...TOUGH TO PINPOINT SPECIFIC CONVECTIVE EPISODES BUT IT
APPEARS THAT ACTIVITY TO THE SOUTHWEST WILL SPREAD INTO THE CWA LATE
THIS AFTERNOON OR EARLY THIS EVENING...THOUGH AGAIN...IT MAY BE
PRECEDED BY LESS FOCUSED ACTIVITY. ADDITIONAL ROUNDS OF STORMS MAY
CONTINUE THROUGH THE OVERNIGHT. BY FRIDAY MORNING...THE SURFACE AND
UPPER LOWS WILL HAVE MOVED LITTLE BUT THE UPPER LOW WILL HAVE
SEVERAL SPOKES OF ENERGY ROTATING AROUND IT. THERE IS GOOD MODEL
AGREEMENT IN A SHORTWAVE DEVELOPING OVER THE CENTRAL/SOUTHERN
ROCKIES EARLY FRIDAY THEN LIFTING NORTHEASTWARD DURING THE DAY AND
BRINGING ANOTHER ROUND OF ORGANIZED STORMS EITHER LATE FRIDAY
MORNING OR EARLY AFTERNOON.
IN TERMS OF THREATS...PRECIPITABLE WATER VALUES OF AROUND 1.8 INCHES
WILL SUPPORT A HEAVY RAIN THREAT TODAY AND TONIGHT WITH A
BRIEF LOWERING OF VALUES FRIDAY MORNING AS DRIER MID LEVEL AIR WORKS
IN BEHIND THE DEPARTING TROUGH. HOWEVER...ANOTHER PUSH OF HIGH PW
AIR WILL ARRIVE WITH THE NEXT EXPECTED WAVE BY FRIDAY AFTERNOON. THE
MAIN AREA OF CONCERN WILL BE THE WESTERN CWA GIVEN THAT THEY HAVE
THE BEST CHANCE OF BEING AFFECTED BY MULTIPLE ROUNDS OF CONVECTION
STARTING AS EARLY AS LATE THIS AFTERNOON. EACH OF THE WAVES SPAWNING
THE CONVECTION WILL BE PROGRESSIVE WHICH LOOKS TO LIMIT THE DURATION
OF HEAVY RAIN BUT 2 TO 3 INCHES BETWEEN NOW AND FRIDAY LOOKS
REASONABLE ON THE LARGE SCALE THOUGH ISOLATED HIGHER AMOUNTS ARE
CERTAINLY POSSIBLE. DECIDED TO GO WITH A FLASH FLOOD WATCH FOR LA
SALLE AND LIVINGSTON COUNTIES GIVEN THE 4-5+ INCHES OF RAINFALL
OBSERVED THERE OVER THE PAST FEW DAYS AND THE EXPECTED RAINFALL
ABOVE. AREAS TO THE NORTH HAVE SEEN FAR LESS RAINFALL SO POTENTIAL
IS LESS CERTAIN THERE AND 1 AND 3 HR FLASH FLOOD GUIDANCE VALUES ARE
1.6 AND 1.9 INCHES RESPECTIVELY AND HIGHER. AREAS TO THE EAST ALONG
THE I-80 CORRIDOR HAVE ALSO SEEN SIGNIFICANT RAINFALL THE PAST FEW
DAYS BUT STILL HAVE QUESTIONS HOW FAR EAST THE HEAVIEST RAINFALL
WILL STRETCH AND ALSO EXPECT A BIT LATER START TO THE BEST ORGANIZED
CONVECTION THERE. AN EXPANSION IS POSSIBLE HOWEVER. IN TERMS OF THE
SEVERE THREAT...STORMS THAT CAN DEVELOP PRIOR TO MID AFTERNOON WILL
HAVE SOME SEVERE THREAT WITH DECENT INSTABILITY AND SUFFICIENT DEEP
LAYER SHEAR FOR ORGANIZATION. AGAIN...THE FORCING DURING THIS PERIOD
IS SUBTLE AT BEST AT THIS POINT AND THERE IS SOME MINIMAL
CAPPING...SO FEEL CHANCES ARE PRETTY LOW. ONCE EVENING ARRIVES...THE
ODDS ARE BETTER THAT AN ORGANIZED CONVECTIVE COMPLEX OR COMPLEXES
WILL MOVE IN. HEAVY RAIN AND DAMAGING WINDS WILL BE THE MAIN
THREATS. SOME OF THE SEVERE THREAT MAY BE CONDITIONAL BASED ON HOW
THINGS DEVELOP UPSTREAM AND IF ANY LATE MORNING/EARLY AFTERNOON
CONVECTION CAN DEVELOP. SEVERE POTENTIAL MAY BE HIGHER FRIDAY
DEPENDING ON CONVECTIVE DEBRIS...BUT LOW LEVEL WIND FIELDS
STRENGTHEN WITH GREATER DEEP LAYER SHEAR AS WELL SO BETTER STORM
ORGANIZATION IS POSSIBLE. DAMAGING WIND/HAIL/ISOLATED TORNADO
THREATS MAY BE HIGHER. WARM AND MUGGY CONDITIONS WILL CONTINUE.
HIGHS TODAY WILL BE TOUGH WITH A BREEZY SOUTH-SOUTHWEST WIND
POINTING TOWARD WARMER READINGS BUT APPROACHING CLOUD COVER ARGUING
AGAINST. WILL CONTINUE WITH MID 80S WITH SOME POTENTIAL FOR HIGHER
VALUES IF CLOUD COVER IS LESS THAN EXPECTED. FRIDAY SHOULD BE
SLIGHTLY COOLER WITH MORE CLOUDS AND HIGHER DAYTIME PRECIP CHANCES.
SATURDAY THROUGH MID WEEK...AN UPPER TROUGH WILL MOVE SOUTHEAST
ACROSS NORTHERN ALBERTA/SASKATCHEWAN FRIDAY NIGHT AND PHASE WITH THE
CLOSED UPPER LOW OVER THE DAKOTAS. THIS WILL ALLOW THE LOW TO OPEN
UP AND THEN SWING SOUTHEASTWARD. IN TURN...THE SURFACE LOW WILL BE
KICKED EASTWARD AS WELL PUSHING THE COLD FRONT INTO THE AREA
SATURDAY. THIS WILL TRIGGER ADDITIONAL CHANCES FOR
CONVECTION...ESPECIALLY ACROSS THE EASTERN HALF OF THE FORECAST AREA
SATURDAY AFTERNOON AND EVENING. THE UPPER TROUGH CROSSES THE AREA
SATURDAY EVENING THOUGH CYCLONIC UPPER FLOW WILL CONTINUE THROUGH
SUNDAY. MUCH COOLER AIR WILL FLOW IN FROM THE NORTH WITH H85 TEMPS
FALLING FROM AROUND +16 TO +4 BY SUNDAY EVENING. SHOWER/ISOLD
THUNDER CHANCES WILL LINGER SUNDAY WITH THE CYCLONIC FLOW. HIGH
PRESSURE WILL SPREAD SOUTHWARD INTO THE PLAINS WHICH WILL PROVIDE
QUIET WEATHER MONDAY. MODEL GUIDANCE DIVERGES TUESDAY WITH HOW THE
UPPER FLOW PATTERN EVOLVES THOUGH IT DOES APPEAR THAT AT LEAST WEAK
UPPER RIDGING WILL MOVE ACROSS TUESDAY BRINGING WARMER MID LEVEL AIR
BUT TROUGHING RETURNS BY MID WEEK. PRECIP CHANCES MAY RETURN AS
EARLY AS TUESDAY EVENING DEPENDING ON HOW THE FLOW PATTERN PANS OUT
BUT GIVEN THE POTENTIAL FOR WAA TO BUILD AHEAD OF THE RIDGE OR AN
ACTIVE ZONAL PATTERN IF THE RIDGE IS WEAKER...SOME PRECIP IS
POSSIBLE. TEMPS WILL BE COOLER SUNDAY WITH HIGHS IN THE MID 60S
NORTH TO AROUND 70 SOUTH WITH MONDAY AND TUESDAY EACH BEING WARMER
THAN THE DAY BEFORE. FLOW OFF THE LAKE SUNDAY THROUGH TUESDAY WILL
KEEP LAKESHORE READINGS COOLER AND LAKE BREEZE DEVELOPMENT MAY
PROPEL COOLER TEMPS FURTHER INLAND EACH AFTERNOON.
MDB
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 20Z...
* ONGOING SCATTERED CONVECTION CONTINUING THROUGH THE EVENING AND
OVERNIGHT.
* COVERAGE OF TSTMS GRADUALLY INCREASING THROUGH REMAINDER OF
AFTERNOON.
* INDIVIDUAL STORMS PULSING UP AND DOWN HAVE POTENTIAL TO PRODUCE
SURFACE WIND GUSTS TO 50 KTS.
ED F
//DISCUSSION...UPDATED 18Z...
AN ACTIVE PERIOD IS EXPECTED WITH SEVERAL BOUTS OF THUNDERSTORMS
POSSIBLE AND GUSTY SOUTHERLY WINDS.
SYNOPTICALLY...AREA OF LOW PRESSURE LIES OVER THE NORTHERN PLAIN AND
WILL GRADUALLY SHIFT NORTHEAST THROUGH THE TAF PERIOD. NORTHERN
ILLINOIS LIES IN A TIGHT SOUTHERLY GRADIENT WITH WINDS GUSTING TO
AROUND 30 KT ALREADY EARLY THIS AFTERNOON AND EXPECTED TO PERSIST
THROUGH THE DAY. WINDS MAY TAPER SOME WITH SUNSET...THEN ARE
EXPECTED TO BECOME GUSTY AGAIN FRIDAY...THOUGH NOT QUITE AS STRONG
AS TODAY.
SEVERAL ROUNDS OF THUNDERSTORMS ARE POSSIBLE...WITH THE DETAILS
STILL A BIT MURKY. FIRST ROUND IS ALREADY STARTING TO TAKE SHAPE
THIS AFTERNOON AS STRONG INSTABILITY HAS DEVELOPED OVER THE AREA
WITH CONVECTION ALREADY DEVELOPING DOWNSTATE AHEAD OF A NEGATIVELY
TILTED TROUGH LIFTING ACROSS THE MID MISSISSIPPI VALLEY. THIS WAVE
WILL CONTINUE NORTHEAST INTO NORTHERN ILLINOIS MID AFTERNOON WITH
SCATTERED STRONG TO SEVERE THUNDERSTORMS EXPECTED OVER THE AREA.
WITH NO SIGNIFICANT LOW LEVEL BOUNDARIES OR FOCUSING MECHANISMS...IT
WILL BE HARD TO IMPOSSIBLE TO PINPOINT EXACTLY WHERE THUNDERSTORMS
WILL DEVELOP...THOUGH THE BEST INSTABILITY HAS SET UP JUST WEST OF
THE CHICAGO TERMINALS. THEN THIS EVENING...NUMEROUS CONVECTIVE
ALLOWING MODELS ARE INDICATING THAT A SECOND ROUND OF CONVECTION
WILL CONGEAL INTO A LINE OFF TO OUR WEST WITH THE DEVELOPMENT OF A
MODERATE TO STRONG LOW LEVEL JET ALONG THE MISSISSIPPI RIVER VALLEY.
THIS LINE IS EXPECTED TO RACE EAST LATE THIS EVENING OR EARLY
OVERNIGHT. FINALLY...WITH SIMILAR CONDITIONS IN PLACE
TOMORROW...WILL BE LOOKING AT MUCH OF THE SAME CONCERNS FRIDAY WITH
RESPECT TO PERIODIC CONVECTIVE CHANCES.
BMD
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
* HIGH CONFIDENCE IN TSTMS CONTINUING THROUGH THE EVENING WITH
GENERAL INCREASING TREND IN COVERAGE.
* LOW CONFIDENCE IN TIMING OF ANY SPECIFIC TSTM CELLS AT SPECIFIC
TERMINALS.
* MEDIUM CONFIDENCE IN LINE OF TSTMS IMPACTING TERMINALS LATE
THIS EVENING.
* MEDIUM CONFIDENCE IN ADDITIONAL TSTMS FRIDAY...LOW CONFIDENCE
IN TIMING.
* MEDIUM TO HIGH CONFIDENCE IN WIND TRENDS.
ED F
//OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z...
* FRIDAY THROUGH SATURDAY...PERIODS OF TSRA/SHRA.
POSSIBLE WITH MVFR CIGS/VIS.
* SUNDAY...CHANCE OF SHRA EARLY...OTRW...VFR.
* MONDAY THROUGH EARLY TUESDAY...VFR. WX NIL.
* LATE TUESDAY THROUGH WEDNESDAY...CHANCE TSRA/SHRA.
KREIN
&&
.MARINE...
1259 PM CDT
THE SHORT TERM OF THE MARINE FORECAST HAS A SMALL CRAFT ADVISORY FOR
STRONG WINDS ACROSS THE ILLINOIS AND NORTHWEST INDIANA NEARSHORE
WATERS.
ACROSS THE OPEN WATERS OF THE LAKE...MAINLY THE NORTHERN THIRD OF
THE LAKE...AREAS OF DENSE FOG CONTINUE.
VERY WARM/MOIST AIR CONTINUES TO SLIDE NORTH ACROSS THE LAKE...AND
WITH THE MUCH COOLER LAKE SURFACE WATER...HAS RESULTED IN AREAS OF
DENSE FOG PERSISTING. IT DOES APPEAR BASED ON LATEST VISIBLE IMAGERY
THAT THE FOG HAS REMAINED FOCUSED ACROSS THE NORTHERN THIRD OF THE
LAKE. OBS HAVE CONTINUED TO SHOW INCREASING GUSTS...WITH SPEEDS
GENERALLY AROUND 20-25KT ACROSS THE SOUTHERN HALF OF THE LAKE.
FURTHER NORTH IT APPEARS THE WINDS ARE SLIGHTLY LESS...WITH SPEEDS
GENERALLY IN THE 15-25KT.
THE TROUGH OF LOW PRESSURE REMAINS CENTERED ACROSS THE CENTRAL
PLAINS...WITH A WEAK LOW PRESSURE LIFTING NORTH INTO THE NORTHERN
PLAINS. AN ASSOCIATED WARM FRONT EXTENDS EAST THROUGH THE UPPER
GREAT LAKES REGION. WITH THE POSITION OF THE LOW PRESSURE AND THE
PERSISTING RIDGE OF HIGH PRESSURE ACROSS THE SOUTHEASTERN UNITED
STATES...THE WIND FLOW WILL REMAIN SOUTHERLY ACROSS THE LAKE. AT
TIMES THROUGH EARLY THIS EVENING GUSTS MAY APPROACH 30 KT...MAINLY
FOR THE SOUTHERN PORTIONS OF THE LAKE INCLUDING THE NEARSHORE
WATERS. AS A RESULT WILL MAINTAIN THE CURRENT SMALL CRAFT ADVISORY
THAT IS IN EFFECT.
THE TROUGH OF LOW PRESSURE POSITIONED OVER THE CENTRAL PLAINS WILL
SLOWLY PUSH EAST...WITH A LOW PRESSURE APPROACHING THE WESTERN GREAT
LAKES SAT MIDDAY. THE RECENT FORECAST TRENDS HAVE BEEN TO SLOW THE
ARRIVAL OF THIS SYSTEM...THUS IT IS POSSIBLE THAT THE MAIN LOW
PRESSURE MAY NOT ARRIVE UNTIL CLOSER TO SAT NIGHT. THEN AN
ASSOCIATED COLD FRONT WILL WILL PUSH EAST ACROSS THE LAKE OVERNIGHT
SAT INTO SUN. WINDS AT THAT POINT WILL TURN WESTERLY THEN NORTHERLY
WITH MUCH COOLER AIR FLOWING OVER THE LAKE.
BEACHLER
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...FLASH FLOOD WATCH...ILZ019-ILZ032...7 PM THURSDAY TO 7 PM
SATURDAY.
IN...NONE.
LM...DENSE FOG ADVISORY...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565
UNTIL 7 AM FRIDAY.
SMALL CRAFT ADVISORY...NEARSHORE WATERS
UNTIL 9 PM THURSDAY.
&&
$$
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FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
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AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
309 PM CDT THU MAY 30 2013
.MESOSCALE DISCUSSION...
309 PM CDT
SCATTERED THUNDERSTORMS CONTINUE TO FIRE ACROSS THE REGION. LACK OF
LOW LEVEL CONVERGENCE AND ANY CONVECTIVE INHIBITION ALONG WITH
INCREASING LARGE SCALE ASCENT AHEAD OF APPROACHING SHORT WAVE
EVIDENT ON WATER VAPOR IMAGERY MOVING INTO WESTERN ILLINOIS SHOULD
CONTINUE TO ALLOW THIS REGIME WITH STORMS GOING UP JUST ABOUT
ANYWHERE.
WIND PROFILERS SHOW A PRETTY TIGHT GRADIENT IN MID LEVEL FLOW WITH
PROFILERS SHOWING 55-60KT WINDS AT 6KM OVER WESTERN ILLINOIS INTO
IA/MO WITH ONLY ABOUT 40KT OF FLOW OVER OUR AREA. UNIDIRECTIONAL
NATURE OF THE FLOW IS MINIMIZING DEEP LAYER SHEAR OVER OUR EASTERN
CWA WITH ABOUT DEEP LAYER SHEAR ABOUT 20-30KT INCREASING TO AROUND
40KT WESTERN CWA. RAP SUGGESTS THAT THE STRONGER SHEAR WILL SPREAD
EASTWARD ACROSS THE CWA THIS EVENING.
LOW LEVEL SHEAR IS NOT OVERLY STRONG AT THIS TIME WITH WELL MIXED
BOUNDARY LAYER...HOWEVER T/TD SPREADS ARE IN THE NEIGHBORHOOD OF
10-15F SO LCL HEIGHTS ARE NOT THAT HIGH SUGGESTING AT LEAST SOME
LIMITED TORNADO THREAT FOR THE NEXT HOUR OR TWO. THIS WILL
PARTICULARLY BE THE CASE WITH ANY CELLS THAT ARE ABLE TO ACHEIVE
MORE DEVIANT RIGHTWARD MOTION AUGMENTING THE LOW LEVEL SHEAR.
LOW LEVEL SHEAR SHOULD INCREASE THIS EVENING WITH DEVELOPMENT OF LOW
LEVEL WIND MAXIMA...SO ASSUMING CONVECTION REMAINS CELLULAR AND
ROOTED IN THE BOUNDARY LAYER THEN TORNADO THREAT COULD INCREASE SOME
FOR A TIME EARLY THIS EVENING. IN THE NEXT HOUR OR TWO THINK THE
PRIMARY HAZARD WILL BE DMG WIND AND HAIL...WITH A SLIGHT TORNADO
THREAT MOSTLY OVER WESTERN CWA.
IZZI
&&
.DISCUSSION...
326 AM CDT
CONVECTIVE TRENDS AND ASSOCIATED HEAVY RAIN AND SEVERE WEATHER
THREAT REMAIN THE FOCUS OF THE FORECAST THIS PERIOD. UPPER AIR
ANALYSIS AND EARLY MORNING WATER VAPOR IMAGERY SHOW A MUCH MORE
AMPLIFIED PATTERN THAN LAST NIGHT WITH A BROAD RIDGE OVER THE
EASTERN THIRD OR SO OF THE COUNTRY WITH A RIDGE AXIS EXTENDING FROM
NORTHERN OHIO TO THE CANADIAN PRAIRIES. THE BASE OF A LONGWAVE
TROUGH IS POSITIONED OVER THE FAR SOUTHERN PLAINS WITH THE AXIS
EXTENDING NORTHWEST TO A CLOSED LOW SPINNING OFF THE BRITISH
COLUMBIA COAST. SEVERAL SHORTWAVES ARE EMBEDDED WITHIN THE
SOUTH-SOUTHWEST FLOW OVER THE CENTER OF THE COUNTRY. AT THE
SURFACE...ONE LOW PRESSURE AREA IS POSITIONED OVER SOUTH DAKOTA WITH
A SECOND OVER THE TX/OK PANHANDLE. A COLD FRONT IS STRETCHED BETWEEN
THESE TWO LOWS WITH A WARM FRONTAL BOUNDARY FROM SOUTH DAKOTA ACROSS
FAR NORTHERN LAKE MICHIGAN.
TODAY THROUGH FRIDAY...AN UPPER LEVEL LOW WILL CLOSE OFF OVER THE
WESTERN DAKOTAS TODAY AS THE MAIN LONGWAVE AXIS PIVOTS NORTHWARD
ACROSS THE CENTRAL/SOUTHERN PLAINS AND MID MISSISSIPPI RIVER VALLEY.
THIS WILL DEEPEN THE SURFACE LOW ACROSS THE DAKOTAS AND HELP PUSH
THE ATTENDANT COLD FRONT INTO FAR WESTERN MINNESOTA AND IOWA BY
EVENING. THERE ARE A RANGE OF POSSIBILITIES WITH REGARD TO
CONVECTIVE EVOLUTION INTO TONIGHT GIVEN THE UPPER FLOW PATTERN AND
PRESENCE OF NUMEROUS EMBEDDED WAVES. WATER VAPOR SHOWS THE LONGWAVE
TROUGH AXIS PIVOTING NORTHEASTWARD ACROSS TX/OK AS IT IS BEING
PUSHED BY A STRONG UPPER JET CORE ON ITS WESTERN FLANK. THE MAIN
TROUGH ITSELF IS THE MOST COHERENT FOCUS FOR CONVECTIVE
DEVELOPMENT...IN ADDITION TO THE NUMEROUS EMBEDDED WAVES. WITH THE
STEERING FLOW PRETTY SELY THIS MORNING...THIS WILL INITIALLY KEEP
ACTIVITY ON A TRAJECTORY WEST OF THE CWA BUT WITH THE MAIN LONGWAVE
TROUGH SHIFTING EASTWARD AS AN UPPER JET MAX PUSHES IT FROM THE WEST
THE MAIN CORRIDOR OF FLOW WILL TRANSLATE EASTWARD SPREADING
CONVECTIVE CHANCES FURTHER INTO THE AREA. CHANCES FOR STORMS WILL
THEREFORE INCREASE FROM WEST TO EAST THROUGH THE DAY...WITH MINIMAL
CHANCES THROUGH LATE MORNING THOUGH THERE IS SUGGESTION OF SOME
SCATTERED DEVELOPMENT THANKS TO A WEAK UPPER WAVE THAT AT THIS POINT
IS NOT REALLY WELL DEFINED ON SATELLITE AND ONLY GENERATING CLOUD
COVER WHICH IS MOVING NORTHWARD INTO SOUTHERN ILLINOIS. BEYOND THIS
MORNING...TOUGH TO PINPOINT SPECIFIC CONVECTIVE EPISODES BUT IT
APPEARS THAT ACTIVITY TO THE SOUTHWEST WILL SPREAD INTO THE CWA LATE
THIS AFTERNOON OR EARLY THIS EVENING...THOUGH AGAIN...IT MAY BE
PRECEDED BY LESS FOCUSED ACTIVITY. ADDITIONAL ROUNDS OF STORMS MAY
CONTINUE THROUGH THE OVERNIGHT. BY FRIDAY MORNING...THE SURFACE AND
UPPER LOWS WILL HAVE MOVED LITTLE BUT THE UPPER LOW WILL HAVE
SEVERAL SPOKES OF ENERGY ROTATING AROUND IT. THERE IS GOOD MODEL
AGREEMENT IN A SHORTWAVE DEVELOPING OVER THE CENTRAL/SOUTHERN
ROCKIES EARLY FRIDAY THEN LIFTING NORTHEASTWARD DURING THE DAY AND
BRINGING ANOTHER ROUND OF ORGANIZED STORMS EITHER LATE FRIDAY
MORNING OR EARLY AFTERNOON.
IN TERMS OF THREATS...PRECIPITABLE WATER VALUES OF AROUND 1.8 INCHES
WILL SUPPORT A HEAVY RAIN THREAT TODAY AND TONIGHT WITH A
BRIEF LOWERING OF VALUES FRIDAY MORNING AS DRIER MID LEVEL AIR WORKS
IN BEHIND THE DEPARTING TROUGH. HOWEVER...ANOTHER PUSH OF HIGH PW
AIR WILL ARRIVE WITH THE NEXT EXPECTED WAVE BY FRIDAY AFTERNOON. THE
MAIN AREA OF CONCERN WILL BE THE WESTERN CWA GIVEN THAT THEY HAVE
THE BEST CHANCE OF BEING AFFECTED BY MULTIPLE ROUNDS OF CONVECTION
STARTING AS EARLY AS LATE THIS AFTERNOON. EACH OF THE WAVES SPAWNING
THE CONVECTION WILL BE PROGRESSIVE WHICH LOOKS TO LIMIT THE DURATION
OF HEAVY RAIN BUT 2 TO 3 INCHES BETWEEN NOW AND FRIDAY LOOKS
REASONABLE ON THE LARGE SCALE THOUGH ISOLATED HIGHER AMOUNTS ARE
CERTAINLY POSSIBLE. DECIDED TO GO WITH A FLASH FLOOD WATCH FOR LA
SALLE AND LIVINGSTON COUNTIES GIVEN THE 4-5+ INCHES OF RAINFALL
OBSERVED THERE OVER THE PAST FEW DAYS AND THE EXPECTED RAINFALL
ABOVE. AREAS TO THE NORTH HAVE SEEN FAR LESS RAINFALL SO POTENTIAL
IS LESS CERTAIN THERE AND 1 AND 3 HR FLASH FLOOD GUIDANCE VALUES ARE
1.6 AND 1.9 INCHES RESPECITVELY AND HIGHER. AREAS TO THE EAST ALONG
THE I-80 CORRIDOR HAVE ALSO SEEN SIGNIFICANT RAINFALL THE PAST FEW
DAYS BUT STILL HAVE QUESTIONS HOW FAR EAST THE HEAVIEST RAINFALL
WILL STRETCH AND ALSO EXPECT A BIT LATER START TO THE BEST ORGANIZED
CONVECTION THERE. AN EXPANSION IS POSSIBLE HOWEVER. IN TERMS OF THE
SEVERE THREAT...STORMS THAT CAN DEVELOP PRIOR TO MID AFTERNOON WILL
HAVE SOME SEVERE THREAT WITH DECENT INSTABILITY AND SUFFICIENT DEEP
LAYER SHEAR FOR ORGANIZATION. AGAIN...THE FORCING DURING THIS PERIOD
IS SUBTLE AT BEST AT THIS POINT AND THERE IS SOME MINIMAL
CAPPING...SO FEEL CHANCES ARE PRETTY LOW. ONCE EVENING ARRIVES...THE
ODDS ARE BETTER THAT AN ORGANIZED CONVECTIVE COMPLEX OR COMPLEXES
WILL MOVE IN. HEAVY RAIN AND DAMAGING WINDS WILL BE THE MAIN
THREATS. SOME OF THE SEVERE THREAT MAY BE CONDITIONAL BASED ON HOW
THINGS DEVELOP UPSTREAM AND IF ANY LATE MORNING/EARLY AFTERNOON
CONVECTION CAN DEVELOP. SEVERE POTENTIAL MAY BE HIGHER FRIDAY
DEPENDING ON CONVECTIVE DEBRIS...BUT LOW LEVEL WIND FIELDS
STRENGTHEN WITH GREATER DEEP LAYER SHEAR AS WELL SO BETTER STORM
ORGANIZATION IS POSSIBLE. DAMAGING WIND/HAIL/ISOLATED TORNADO
THREATS MAY BE HIGHER. WARM AND MUGGY CONDITIONS WILL CONTINUE.
HIGHS TODAY WILL BE TOUGH WITH A BREEZY SOUTH-SOUTHWEST WIND
POINTING TOWARD WARMER READINGS BUT APPROACHING CLOUD COVER ARGUING
AGAINST. WILL CONTINUE WITH MID 80S WITH SOME POTENTIAL FOR HIGHER
VALUES IF CLOUD COVER IS LESS THAN EXPECTED. FRIDAY SHOULD BE
SLIGHTLY COOLER WITH MORE CLOUDS AND HIGHER DAYTIME PRECIP CHANCES.
SATURDAY THROUGH MID WEEK...AN UPPER TROUGH WILL MOVE SOUTHEAST
ACROSS NORTHERN ALBERTA/SASKATCHEWAN FRIDAY NIGHT AND PHASE WITH THE
CLOSED UPPER LOW OVER THE DAKOTAS. THIS WILL ALLOW THE LOW TO OPEN
UP AND THEN SWING SOUTHEASTWARD. IN TURN...THE SURFACE LOW WILL BE
KICKED EASTWARD AS WELL PUSHING THE COLD FRONT INTO THE AREA
SATURDAY. THIS WILL TRIGGER ADDITIONAL CHANCES FOR
CONVECTION...ESPECIALLY ACROSS THE EASTERN HALF OF THE FORECAST AREA
SATURDAY AFTERNOON AND EVENING. THE UPPER TROUGH CROSSES THE AREA
SATURDAY EVENING THOUGH CYCLONIC UPPER FLOW WILL CONTINUE THROUGH
SUNDAY. MUCH COOLER AIR WILL FLOW IN FROM THE NORTH WITH H85 TEMPS
FALLING FROM AROUND +16 TO +4 BY SUNDAY EVENING. SHOWER/ISOLD
THUNDER CHANCES WILL LINGER SUNDAY WITH THE CYCLONIC FLOW. HIGH
PRESSURE WILL SPREAD SOUTHWARD INTO THE PLAINS WHICH WILL PROVIDE
QUIET WEATHER MONDAY. MODEL GUIDANCE DIVERGES TUESDAY WITH HOW THE
UPPER FLOW PATTERN EVOLVES THOUGH IT DOES APPEAR THAT AT LEAST WEAK
UPPER RIDGING WILL MOVE ACROSS TUESDAY BRINGING WARMER MID LEVEL AIR
BUT TROUGHING RETURNS BY MID WEEK. PRECIP CHANCES MAY RETURN AS
EARLY AS TUESDAY EVENING DEPENDING ON HOW THE FLOW PATTERN PANS OUT
BUT GIVEN THE POTENTIAL FOR WAA TO BUILD AHEAD OF THE RIDGE OR AN
ACTIVE ZONAL PATTERN IF THE RIDGE IS WEAKER...SOME PRECIP IS
POSSIBLE. TEMPS WILL BE COOLER SUNDAY WITH HIGHS IN THE MID 60S
NORTH TO AROUND 70 SOUTH WITH MONDAY AND TUESDAY EACH BEING WARMER
THAN THE DAY BEFORE. FLOW OFF THE LAKE SUNDAY THROUGH TUESDAY WILL
KEEP LAKESHORE READINGS COOLER AND LAKE BREEZE DEVELOPMENT MAY
PROPEL COOLER TEMPS FURTHER INLAND EACH AFTERNOON.
MDB
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 18Z...
* SEVERAL ROUNDS OF THUNDERSTORMS POSSIBLE.
* GUSTY SOUTHERLY WINDS.
BMD
//DISCUSSION...UPDATED 18Z...
AN ACTIVE PERIOD IS EXPECTED WITH SEVERAL BOUTS OF THUNDERSTORMS
POSSIBLE AND GUSTY SOUTHERLY WINDS.
SYNOPTICALLY...AREA OF LOW PRESSURE LIES OVER THE NORTHERN PLAIN AND
WILL GRADUALLY SHIFT NORTHEAST THROUGH THE TAF PERIOD. NORTHERN
ILLINOIS LIES IN A TIGHT SOUTHERLY GRADIENT WITH WINDS GUSTING TO
AROUND 30 KT ALREADY EARLY THIS AFTERNOON AND EXPECTED TO PERSIST
THROUGH THE DAY. WINDS MAY TAPER SOME WITH SUNSET...THEN ARE
EXPECTED TO BECOME GUSTY AGAIN FRIDAY...THOUGH NOT QUITE AS STRONG
AS TODAY.
SEVERAL ROUNDS OF THUNDERSTORMS ARE POSSIBLE...WITH THE DETAILS
STILL A BIT MURKY. FIRST ROUND IS ALREADY STARTING TO TAKE SHAPE
THIS AFTERNOON AS STRONG INSTABILITY HAS DEVELOPED OVER THE AREA
WITH CONVECTION ALREADY DEVELOPING DOWNSTATE AHEAD OF A NEGATIVELY
TILTED TROUGH LIFTING ACROSS THE MID MISSISSIPPI VALLEY. THIS WAVE
WILL CONTINUE NORTHEAST INTO NORTHERN ILLINOIS MID AFTERNOON WITH
SCATTERED STRONG TO SEVERE THUNDERSTORMS EXPECTED OVER THE AREA.
WITH NO SIGNIFICANT LOW LEVEL BOUNDARIES OR FOCUSING MECHANISMS...IT
WILL BE HARD TO IMPOSSIBLE TO PINPOINT EXACTLY WHERE THUNDERSTORMS
WILL DEVELOP...THOUGH THE BEST INSTABILITY HAS SET UP JUST WEST OF
THE CHICAGO TERMINALS. THEN THIS EVENING...NUMEROUS CONVECTIVE
ALLOWING MODELS ARE INDICATING THAT A SECOND ROUND OF CONVECTION
WILL CONGEAL INTO A LINE OFF TO OUR WEST WITH THE DEVELOPMENT OF A
MODERATE TO STRONG LOW LEVEL JET ALONG THE MISSISSIPPI RIVER VALLEY.
THIS LINE IS EXPECTED TO RACE EAST LATE THIS EVENING OR EARLY
OVERNIGHT. FINALLY...WITH SIMILAR CONDITIONS IN PLACE
TOMORROW...WILL BE LOOKING AT MUCH OF THE SAME CONCERNS FRIDAY WITH
RESPECT TO PERIODIC CONVECTIVE CHANCES.
BMD
//ORD AND MDW CONFIDENCE...UPDATED 18Z...
* MEDIUM TO HIGH CONFIDENCE IN TSTRMS THIS AFTERNOON...LOW
CONFIDENCE IN DIRECT IMPACTS TO TERMINALS DUE TO SCATTERED
COVERAGE.
* MEDIUM CONFIDENCE IN LINE OF TSTRMS IMPACTING TERMINALS LATE
THIS EVENING.
* MEDIUM CONFIDENCE IN ADDITIONAL TSTRMS FRIDAY...LOW CONFIDENCE
IN TIMING.
* MEDIUM TO HIGH CONFIDENCE IN WIND TRENDS.
BMD
//OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z...
* FRIDAY THROUGH SATURDAY...PERIODS OF TSRA/SHRA.
POSSIBLE WITH MVFR CIGS/VIS.
* SUNDAY...CHANCE OF SHRA EARLY...OTRW...VFR.
* MONDAY THROUGH EARLY TUESDAY...VFR. WX NIL.
* LATE TUESDAY THROUGH WEDNESDAY...CHANCE TSRA/SHRA.
KREIN
&&
.MARINE...
1259 PM CDT
THE SHORT TERM OF THE MARINE FORECAST HAS A SMALL CRAFT ADVISORY FOR
STRONG WINDS ACROSS THE ILLINOIS AND NORTHWEST INDIANA NEARSHORE
WATERS.
ACROSS THE OPEN WATERS OF THE LAKE...MAINLY THE NORTHERN THIRD OF
THE LAKE...AREAS OF DENSE FOG CONTINUE.
VERY WARM/MOIST AIR CONTINUES TO SLIDE NORTH ACROSS THE LAKE...AND
WITH THE MUCH COOLER LAKE SURFACE WATER...HAS RESULTED IN AREAS OF
DENSE FOG PERSISTING. IT DOES APPEAR BASED ON LATEST VISIBLE IMAGERY
THAT THE FOG HAS REMAINED FOCUSED ACROSS THE NORTHERN THIRD OF THE
LAKE. OBS HAVE CONTINUED TO SHOW INCREASING GUSTS...WITH SPEEDS
GENERALLY AROUND 20-25KT ACROSS THE SOUTHERN HALF OF THE LAKE.
FURTHER NORTH IT APPEARS THE WINDS ARE SLIGHTLY LESS...WITH SPEEDS
GENERALLY IN THE 15-25KT.
THE TROUGH OF LOW PRESSURE REMAINS CENTERED ACROSS THE CENTRAL
PLAINS...WITH A WEAK LOW PRESSURE LIFTING NORTH INTO THE NORTHERN
PLAINS. AN ASSOCIATED WARM FRONT EXTENDS EAST THROUGH THE UPPER
GREAT LAKES REGION. WITH THE POSITION OF THE LOW PRESSURE AND THE
PERSISTING RIDGE OF HIGH PRESSURE ACROSS THE SOUTHEASTERN UNITED
STATES...THE WIND FLOW WILL REMAIN SOUTHERLY ACROSS THE LAKE. AT
TIMES THROUGH EARLY THIS EVENING GUSTS MAY APPROACH 30 KT...MAINLY
FOR THE SOUTHERN PORTIONS OF THE LAKE INCLUDING THE NEARSHORE
WATERS. AS A RESULT WILL MAINTAIN THE CURRENT SMALL CRAFT ADVISORY
THAT IS IN EFFECT.
THE TROUGH OF LOW PRESSURE POSITIONED OVER THE CENTRAL PLAINS WILL
SLOWLY PUSH EAST...WITH A LOW PRESSURE APPROACHING THE WESTERN GREAT
LAKES SAT MIDDAY. THE RECENT FORECAST TRENDS HAVE BEEN TO SLOW THE
ARRIVAL OF THIS SYSTEM...THUS IT IS POSSIBLE THAT THE MAIN LOW
PRESSURE MAY NOT ARRIVE UNTIL CLOSER TO SAT NIGHT. THEN AN
ASSOCIATED COLD FRONT WILL WILL PUSH EAST ACROSS THE LAKE OVERNIGHT
SAT INTO SUN. WINDS AT THAT POINT WILL TURN WESTERLY THEN NORTHERLY
WITH MUCH COOLER AIR FLOWING OVER THE LAKE.
BEACHLER
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...FLASH FLOOD WATCH...ILZ019-ILZ032...7 PM THURSDAY TO 7 PM
SATURDAY.
IN...NONE.
LM...DENSE FOG ADVISORY...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565
UNTIL 7 AM FRIDAY.
SMALL CRAFT ADVISORY...NEARSHORE WATERS
UNTIL 9 PM THURSDAY.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
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WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1259 PM CDT THU MAY 30 2013
.DISCUSSION...
ISSUED 1030 AM CDT THU MAY 30 2013
MORNING SURFACE ANALYSIS SHOWS HIGH PRESSURE ANCHORED ALONG THE
EAST COAST AND LOW PRESSURE CENTERED OVER SOUTH DAKOTA. THE
PRESSURE GRADIENT BETWEEN THESE TWO FEATURES IS CREATING
STRONG/GUSTY SOUTHERLY WINDS ACROSS CENTRAL ILLINOIS...WITH THE
15Z/10AM OBS INDICATING GUSTS ALREADY EXCEEDING 30 MPH IN A FEW
LOCATIONS. RADAR MOSAIC HAS BEEN FAIRLY QUIET SO FAR...WITH ONLY A
FEW ISOLATED SHOWERS ACROSS EAST-CENTRAL ILLINOIS EARLIER THIS
MORNING. DESPITE RATHER BULLISH PRECIP DEVELOPMENT IN THE WARM
SECTOR AS ADVERTISED BY THE 12Z NAM...THINK ONLY ISOLATED
SHOWERS/THUNDER WILL OCCUR ACROSS THE AREA THROUGH EARLY
AFTERNOON. AS ATMOSPHERE DESTABILIZES...SCATTERED SHOWERS/STORMS
WILL DEVELOP BY MID TO LATE AFTERNOON. LATEST HRRR SUGGESTS THE
MOST WIDESPREAD CONVECTION WILL REMAIN WEST OF THE MISSISSIPPI
RIVER UNTIL THIS EVENING WHEN STORMS TRACK INTO AT LEAST THE
WESTERN HALF OF THE KILX CWA. HAVE UPDATED FORECAST TO LOWER POPS
THIS MORNING...FEATURING ONLY ISOLATED SHOWERS THROUGH EARLY
AFTERNOON. WILL GO WITH SCATTERED WORDING THIS AFTERNOON...THEN
WILL HIT POPS HARD TONIGHT WHEN BETTER FORCING APPROACHES FROM THE
WEST. ZONE UPDATE HAS ALREADY BEEN ISSUED.
&&
.AVIATION...
ISSUED 1258 PM CDT THU MAY 30 2013
SCATTERED CONVECTION WILL CONTINUE TO DEVELOP WITHIN THE WARM SECTOR
ACROSS CENTRAL ILLINOIS THIS AFTERNOON. THE STORMS WILL TRACK FROM
SOUTH TO NORTH ACROSS THE AREA...PRIMARILY IMPACTING LOCATIONS
WEST OF I-57. BASED ON LATEST RADAR DATA...HAVE INCLUDED A TEMPO
GROUP FOR THUNDER AT ALL TAF SITES EXCEPT KCMI. WILL NEED TO
MONITOR LARGER COMPLEX OF STORMS DEVELOPING FURTHER WEST OVER THE
CENTRAL PLAINS AS IT MAY WORK ITS WAY EASTWARD INTO THE AREA
TONIGHT. AT THIS TIME...WILL FOCUS ON THE IMMEDIATE CONVECTION
THIS AFTERNOON/EARLY EVENING AND KEEP OVERNIGHT FORECAST DRY
UNTIL TRENDS BECOME MORE APPARENT. WINDS WILL BE STRONG/GUSTY
THROUGH THE PERIOD. GUSTS WILL FREQUENTLY EXCEED 30KT THIS
AFTERNOON...THEN WINDS WILL DIMINISH TO BETWEEN 10 AND 15KT LATE
TONIGHT INTO FRIDAY MORNING.
BARNES
&&
.PREV DISCUSSION...
ISSUED 316 AM CDT THU MAY 30 2013
SHORT TERM...TODAY THROUGH SATURDAY
07Z SURFACE MAP SHOWED DOUBLE-BARREL LOW PRESSURE OVER THE PLAINS
WITH ONE LOW CENTER IN CENTRAL SD AND A SOUTHERN LOW NEAR THE
OK/TX PANHANDLE. TIGHTENING MSLP GRADIENT BETWEEN THIS AND SFC
HIGH ALONG THE EAST COAST CAUSED 10-20 MPH S/SE WINDS
OVERNIGHT...KEEPING DEWPOINTS UP IN THE MID 60S AND EARLY MORNING
TEMPS IN THE UPPER 60S TO LOWER 70S. NEGATIVELY TILTED MID LEVEL
TROF WAS LIFTING INTO THE WESTERN HIGH PLAINS RESPONSIBLE FOR
LARGE AREA OF CONVECTION FROM THE PLAINS INTO THE UPPER MIDWEST.
WATER VAPOR IMAGERY INDICATED A WEAK WAVE AND MID LEVEL MOISTURE
POOL TRACKING NORTH FROM THE LOWER MS VALLEY...ON THE BACK SIDE OF
THE SUB-TROPICAL RIDGE CENTERED OFF THE EAST COAST. SHORT RANGE
HI-RES MODELS DEVELOP CONVECTION WITH THIS FEATURE AS IT SHIFTS NE
INTO THE LOWER OHIO VALLEY THIS MORNING...AND LATEST RADAR MOSAIC
INDICATED A SHOWER IN EAST CENTRAL IL AND A FEW MORE IN SE MO.
THUS MAY SEE A SLIGHTLY MORE FOCUSED AREA OF SCATTERED
SHOWERS/STORMS EAST OF I-57 INTO MID MORNING. OTHERWISE DEEPER
CONVECTION IS EXPECTED TO DEVELOP OVER MISSOURI AND IOWA THIS
AFTERNOON ASSOCIATED WITH A SIGNIFICANT SHORTWAVE EJECTING OUT OF
THE WESTERN TROF. CONVECTIVE MODELS SHOW THIS ENTERING THE WESTERN
CWA LATER THIS AFTERNOON AND EVENING...IN A WEAKENING FASHION AS
LESS INSTABILITY IS INDICATED EAST OF THE MS RIVER. MOIST PROFILES
ALSO SUGGEST A LOWER SVR THREAT...HOWEVER WITH DECENT WIND FIELDS
ALOFT WOULD NOT BE SURPRISED TO SEE SOME STRONG OR NEAR SVR
STORMS. ASIDE FROM POSSIBLE CONVECTION...ANOTHER ISSUE WILL BRISK
AND GUSTY SOUTH WINDS IN TIGHT GRADIENT. BUFKIT DATA SHOWS GUSTS
OVER 30 KTS DURING PEAK HEATING BUT CLOUD COVER COULD TEMPER
HIGHER GUSTS.
FAIRLY STRONG MODEL SIGNALS THAT AN MCS WILL FORM OVER KS/MO
TONIGHT AND LIFT NORTHEAST INTO THE CWA ON FRIDAY. THIS
SHOULD BE MAINTAINED BY A VIGOROUS 40-60 KT LLJ AND COULD BRING
ANOTHER ROUND OF HEAVY RAIN TO THE NW CWA INTO MIDDAY. THE EFFECTS
OF THIS MCS WILL IMPACT CONVECTIVE DEVELOPMENT LATER IN THE DAY
AND IF ATMOSPHERE CAN RECOVER THEN STRONG STORMS MAY REDEVELOP ALONG
THE LINGERING OUTFLOW BOUNDARY. BETTER WIND FIELDS ALOFT
ASSOCIATED WITH THE APPROACHING UPPER TROF WILL CONTRIBUTE TO
HIGHER BULK SHEAR AND THE POTENTIAL FOR MORE ORGANIZED SEVERE
WEATHER.
AS THE UPPER TROF STEADILY SHIFTS EAST...IT WILL DRIVE A COLD
FRONT INTO THE STATE ON SATURDAY. FRONTAL TIMING WILL BE CRITICAL
FOR ANOTHER ROUND OF POSSIBLE SEVERE STORMS AND HEAVY RAIN...AND
00Z MODELS ARE A FEW HOURS QUICKER WITH THE FRONT THAT PREVIOUS
RUNS. THIS WOULD FAVOR BEST CHANCE OF REDEVELOPMENT ALONG THE
FRONT OR PRE-FRONTAL TROF FOR THE CENTRAL OR EASTERN CWA SATURDAY
AFTERNOON INTO EVENING.
WITH THE THREAT FOR HEAVY RAIN STARTING LATER THIS AFTERNOON
ACROSS THE WEST...AND CONTINUING UNTIL THE COLD FRONTAL PASSAGE
SATURDAY HAVE DECIDED TO GO WITH ANOTHER FLASH FLOOD WATCH
ALONG/WEST OF I-55. THIS WILL BE IN EFFECT THIS AFTERNOON THROUGH
SATURDAY AFTERNOON. SEE HYDROLOGY SECTION BELOW FOR MORE INFO ON
HEAVY RAIN/FLOOD POTENTIAL.
LONG TERM...SUNDAY THROUGH WEDNESDAY
THE POST-FRONTAL AIRMASS WILL BRING A RETURN TO MUCH COOLER AND
DRIER WEATHER FOR THE LAST HALF OF THE WEEKEND. A DEEP TROF IS
FORECAST TO ROTATE SOUTH INTO THE NORTHERN GREAT LAKES BY LATE
SUNDAY WITH A CHILLY...FOR EARLY SUMMER...-24C 500 MB AIRMASS.
CANADIAN HIGH PRESSURE AT THE SURFACE WILL BUILD INTO THE GREAT
LAKES BY EARLY NEXT WEEK...AND CONTINUE TO PROVIDE A COOL
NORTHERLY FLOW TO CENTRAL IL. THUS TEMPERATURES ARE EXPECTED TO BE
SEVERAL DEGREES BELOW NORMAL INTO TUESDAY. BY LATE TUESDAY AND
WEDNESDAY...THE NEXT UPPER LEVEL WAVE PUSHING INTO THE PLAINS WILL
DEVELOP LOW PRESSURE TO OUR WEST. WARM ADVECTION PRECIP WITH THIS
FEATURE WILL SPREAD RAIN CHANCES EAST OF THE MS RIVER FOR MID-
WEEK.
25
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH THROUGH SATURDAY EVENING FOR ILZ027>031-
036>038-040>042-047>051.
&&
$$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1030 AM CDT THU MAY 30 2013
.DISCUSSION...
ISSUED 1030 AM CDT THU MAY 30 2013
MORNING SURFACE ANALYSIS SHOWS HIGH PRESSURE ANCHORED ALONG THE
EAST COAST AND LOW PRESSURE CENTERED OVER SOUTH DAKOTA. THE
PRESSURE GRADIENT BETWEEN THESE TWO FEATURES IS CREATING
STRONG/GUSTY SOUTHERLY WINDS ACROSS CENTRAL ILLINOIS...WITH THE
15Z/10AM OBS INDICATING GUSTS ALREADY EXCEEDING 30 MPH IN A FEW
LOCATIONS. RADAR MOSAIC HAS BEEN FAIRLY QUIET SO FAR...WITH ONLY A
FEW ISOLATED SHOWERS ACROSS EAST-CENTRAL ILLINOIS EARLIER THIS
MORNING. DESPITE RATHER BULLISH PRECIP DEVELOPMENT IN THE WARM
SECTOR AS ADVERTISED BY THE 12Z NAM...THINK ONLY ISOLATED
SHOWERS/THUNDER WILL OCCUR ACROSS THE AREA THROUGH EARLY
AFTERNOON. AS ATMOSPHERE DESTABILIZES...SCATTERED SHOWERS/STORMS
WILL DEVELOP BY MID TO LATE AFTERNOON. LATEST HRRR SUGGESTS THE
MOST WIDESPREAD CONVECTION WILL REMAIN WEST OF THE MISSISSIPPI
RIVER UNTIL THIS EVENING WHEN STORMS TRACK INTO AT LEAST THE
WESTERN HALF OF THE KILX CWA. HAVE UPDATED FORECAST TO LOWER POPS
THIS MORNING...FEATURING ONLY ISOLATED SHOWERS THROUGH EARLY
AFTERNOON. WILL GO WITH SCATTERED WORDING THIS AFTERNOON...THEN
WILL HIT POPS HARD TONIGHT WHEN BETTER FORCING APPROACHES FROM THE
WEST. ZONE UPDATE HAS ALREADY BEEN ISSUED.
BARNES
&&
.AVIATION...
ISSUED 627 AM CDT THU MAY 30 2013
A STRONG LOW LEVEL JET AND AMPLY MOISTURE IN THE LOWER TROPOSPHERE WILL
FUEL SHOWERS AND STORMS TODAY AND TONIGHT. THE TIMING OF THE
STORMS IS STILL IN QUESTION...BUT HIGHER CHANCES APPEAR TO BE LATER
THIS AFTERNOON AND THIS EVENING. WILL CONTINUE WITH TEMPO GROUPS
FOR MVFR VIS AND CIG DURING THAT TIME. A FEW STORMS MAY BUBBLE UP
IN THE WEAKLY CAPPED AIRMASS ALREADY BY 17Z FOR PIA AND SPI. RADAR
AND SATELLITE LOOPS SHOW CONVECTIVE ELEMENTS ALREADY APPROACHING
SOUTHWESTERN IL FROM MISSOURI...ASSOCIATED WITH A MESOSCALE VORTEX
THAT WILL CLIP WESTERN IL THIS MORNING. THE REMNANTS OF THOSE
EARLY MORNING STORMS COULD AFFECT PIA AND SPI LATER THIS MORNING.
OTHERWISE...A STRONGER LINE OF STORMS IS FORECAST TO DEVELOP IN
MISSOURI LATER THIS AFTERNOON AND MOVE INTO CENTRAL IL. SOME
MODELS TIME THE STORMS STARTING IN THE EVENING...BUT WITH
BOUNDARIES STILL IN THE AREA...WE MAY SEE SPORADIC STORMS ERUPT
THIS AFTERNOON EVEN AHEAD OF THAT SYSTEM.
MVFR OR IFR CONDITIONS ARE POSSIBLE DURING THE STRONGER
STORMS...BUT THE TIMING OF IFR IS TOO VAGUE AT THIS POINT...SO WE
DID NOT GO THAT LOW WITH THIS SET OF TAFS.
WINDS WILL INCREASE QUICKLY THIS MORNING AS 55KT WINDS ARE NOT FAR
OFF OF THE SURFACE. SOUTHERLY GUSTS TODAY MAY REACH OVER 30KT AT
TIMES. IT WILL REMAIN BREEZY EVEN AFTER SUNSET THIS EVENING...WITH
SUSTAINED WINDS IN THE 14-17KT RANGE THROUGH AT LEAST 06Z.
SHIMON
&&
.HYDROLOGY...
ISSUED 316 AM CDT THU MAY 30 2013
FLASH FLOOD GUIDANCE REMAINS LOW /LESS THAN 1.5 IN/HR/ FOR AREAS WEST
OF I-55 WHICH RECEIVED HEAVIER RAINS IN RECENT DAYS. THE POTENTIAL
EXISTS FOR SEVERAL ROUNDS OF CONVECTION TO IMPACT THESE AREAS
AGAIN LATER TODAY AND ESPECIALLY FRIDAY...INTO SATURDAY UNTIL THE
COLD FRONT PASSES. CURRENT FORECASTS SHOW 2 TO 4 INCHES OF
RAIN...WITH HIGHER AMOUNTS POSSIBLE IF TRAINING OF STORMS OCCURS.
THUS WILL HAVE A FLASH FLOOD WATCH I-55 AND WEST IN EFFECT THIS
AFTERNOON THROUGH SATURDAY AFTERNOON. MUCH OF THE ADDITIONAL RAIN
WILL RUN OFF INTO CREEKS...STREAMS...AND RIVERS. THIS WILL CAUSE
ADDITIONAL RISES ON RIVERS THAT ARE ALREADY IN FLOOD...INCLUDING
THE SPOON AND ILLINOIS. PORTIONS OF THE MACKINAW AND SANGAMON
RIVERS WILL ALSO BE PRONE TO FLOODING IF THE HEAVIER RAINS DO
MATERIALIZE.
25
&&
.PREV DISCUSSION...
ISSUED 316 AM CDT THU MAY 30 2013
SHORT TERM...TODAY THROUGH SATURDAY
07Z SURFACE MAP SHOWED DOUBLE-BARREL LOW PRESSURE OVER THE PLAINS
WITH ONE LOW CENTER IN CENTRAL SD AND A SOUTHERN LOW NEAR THE
OK/TX PANHANDLE. TIGHTENING MSLP GRADIENT BETWEEN THIS AND SFC
HIGH ALONG THE EAST COAST CAUSED 10-20 MPH S/SE WINDS
OVERNIGHT...KEEPING DEWPOINTS UP IN THE MID 60S AND EARLY MORNING
TEMPS IN THE UPPER 60S TO LOWER 70S. NEGATIVELY TILTED MID LEVEL
TROF WAS LIFTING INTO THE WESTERN HIGH PLAINS RESPONSIBLE FOR
LARGE AREA OF CONVECTION FROM THE PLAINS INTO THE UPPER MIDWEST.
WATER VAPOR IMAGERY INDICATED A WEAK WAVE AND MID LEVEL MOISTURE
POOL TRACKING NORTH FROM THE LOWER MS VALLEY...ON THE BACK SIDE OF
THE SUB-TROPICAL RIDGE CENTERED OFF THE EAST COAST. SHORT RANGE
HI-RES MODELS DEVELOP CONVECTION WITH THIS FEATURE AS IT SHIFTS NE
INTO THE LOWER OHIO VALLEY THIS MORNING...AND LATEST RADAR MOSAIC
INDICATED A SHOWER IN EAST CENTRAL IL AND A FEW MORE IN SE MO.
THUS MAY SEE A SLIGHTLY MORE FOCUSED AREA OF SCATTERED
SHOWERS/STORMS EAST OF I-57 INTO MID MORNING. OTHERWISE DEEPER
CONVECTION IS EXPECTED TO DEVELOP OVER MISSOURI AND IOWA THIS
AFTERNOON ASSOCIATED WITH A SIGNIFICANT SHORTWAVE EJECTING OUT OF
THE WESTERN TROF. CONVECTIVE MODELS SHOW THIS ENTERING THE WESTERN
CWA LATER THIS AFTERNOON AND EVENING...IN A WEAKENING FASHION AS
LESS INSTABILITY IS INDICATED EAST OF THE MS RIVER. MOIST PROFILES
ALSO SUGGEST A LOWER SVR THREAT...HOWEVER WITH DECENT WIND FIELDS
ALOFT WOULD NOT BE SURPRISED TO SEE SOME STRONG OR NEAR SVR
STORMS. ASIDE FROM POSSIBLE CONVECTION...ANOTHER ISSUE WILL BRISK
AND GUSTY SOUTH WINDS IN TIGHT GRADIENT. BUFKIT DATA SHOWS GUSTS
OVER 30 KTS DURING PEAK HEATING BUT CLOUD COVER COULD TEMPER
HIGHER GUSTS.
FAIRLY STRONG MODEL SIGNALS THAT AN MCS WILL FORM OVER KS/MO
TONIGHT AND LIFT NORTHEAST INTO THE CWA ON FRIDAY. THIS
SHOULD BE MAINTAINED BY A VIGOROUS 40-60 KT LLJ AND COULD BRING
ANOTHER ROUND OF HEAVY RAIN TO THE NW CWA INTO MIDDAY. THE EFFECTS
OF THIS MCS WILL IMPACT CONVECTIVE DEVELOPMENT LATER IN THE DAY
AND IF ATMOSPHERE CAN RECOVER THEN STRONG STORMS MAY REDEVELOP ALONG
THE LINGERING OUTFLOW BOUNDARY. BETTER WIND FIELDS ALOFT
ASSOCIATED WITH THE APPROACHING UPPER TROF WILL CONTRIBUTE TO
HIGHER BULK SHEAR AND THE POTENTIAL FOR MORE ORGANIZED SEVERE
WEATHER.
AS THE UPPER TROF STEADILY SHIFTS EAST...IT WILL DRIVE A COLD
FRONT INTO THE STATE ON SATURDAY. FRONTAL TIMING WILL BE CRITICAL
FOR ANOTHER ROUND OF POSSIBLE SEVERE STORMS AND HEAVY RAIN...AND
00Z MODELS ARE A FEW HOURS QUICKER WITH THE FRONT THAT PREVIOUS
RUNS. THIS WOULD FAVOR BEST CHANCE OF REDEVELOPMENT ALONG THE
FRONT OR PRE-FRONTAL TROF FOR THE CENTRAL OR EASTERN CWA SATURDAY
AFTERNOON INTO EVENING.
WITH THE THREAT FOR HEAVY RAIN STARTING LATER THIS AFTERNOON
ACROSS THE WEST...AND CONTINUING UNTIL THE COLD FRONTAL PASSAGE
SATURDAY HAVE DECIDED TO GO WITH ANOTHER FLASH FLOOD WATCH
ALONG/WEST OF I-55. THIS WILL BE IN EFFECT THIS AFTERNOON THROUGH
SATURDAY AFTERNOON. SEE HYDROLOGY SECTION BELOW FOR MORE INFO ON
HEAVY RAIN/FLOOD POTENTIAL.
LONG TERM...SUNDAY THROUGH WEDNESDAY
THE POST-FRONTAL AIRMASS WILL BRING A RETURN TO MUCH COOLER AND
DRIER WEATHER FOR THE LAST HALF OF THE WEEKEND. A DEEP TROF IS
FORECAST TO ROTATE SOUTH INTO THE NORTHERN GREAT LAKES BY LATE
SUNDAY WITH A CHILLY...FOR EARLY SUMMER...-24C 500 MB AIRMASS.
CANADIAN HIGH PRESSURE AT THE SURFACE WILL BUILD INTO THE GREAT
LAKES BY EARLY NEXT WEEK...AND CONTINUE TO PROVIDE A COOL
NORTHERLY FLOW TO CENTRAL IL. THUS TEMPERATURES ARE EXPECTED TO BE
SEVERAL DEGREES BELOW NORMAL INTO TUESDAY. BY LATE TUESDAY AND
WEDNESDAY...THE NEXT UPPER LEVEL WAVE PUSHING INTO THE PLAINS WILL
DEVELOP LOW PRESSURE TO OUR WEST. WARM ADVECTION PRECIP WITH THIS
FEATURE WILL SPREAD RAIN CHANCES EAST OF THE MS RIVER FOR MID-
WEEK.
25
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH THROUGH SATURDAY EVENING FOR ILZ027>031-
036>038-040>042-047>051.
&&
$$
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1030 PM EDT FRI MAY 31 2013
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 353 PM EDT FRI MAY 31 2013
SEVERAL ROUNDS OF SHOWERS AND THUNDERSTORMS WILL IMPACT CENTRAL
INDIANA AS A SLOW MOVING COLD FRONT APPROACHES. THE FRONT WILL MOVE
THROUGH THE REGION SATURDAY NIGHT WITH COOLER AND MUCH DRIER AIR
SPREADING IN WITH HIGH PRESSURE FOR THE FIRST HALF OF THE WORK WEEK.
CHANCES FOR THUNDERSTORMS WILL RETURN THURSDAY AND FRIDAY AS A COLD
FRONT MOVES INTO THE REGION.
&&
.NEAR TERM /REST OF TONIGHT/...
ISSUED AT 1010 PM EDT FRI MAY 31 2013
A FEW THUNDERSTORMS WILL BRUSH NORTHERN CARROLL AND POSSIBLY HOWARD
COUNTY IN THE NEXT HOUR. OTHERWISE...THERE WILL BE A TEMPORARY LULL
IN THUNDERSTORMS ACROSS OUR REGION UNTIL AREA OF STRONG STORMS OVER
WESTERN ILLINOIS AND MISSOURI MOVE INTO WESTERN INDIANA BY 06Z.
THERE MAY BE SEVERAL HOURS OF SEVERE STORMS OVER WESTERN HALF OF OUR
REGION...THEN SEVERE THREAT WILL LESSEN AS STORMS MOVE INTO LESS
UNSTABLE AIR FARTHER EAST.
OF MORE CONCERN WILL BE HEAVY RAIN THREAT AS THUNDERSTORMS TRAIN
ACROSS EAST CENTRAL MISSOURI...SOUTHERN ILLINOIS INTO SOUTHWEST
PORTIONS OF OUR REGION. QPF AMOUNTS OF ONE TO TWO INCHES POSSIBLE
IN SOME AREAS WITH MORE RAIN OCCURRING SATURDAY. DID NOT MAKE ANY
CHANGES TO FLASH FLOOD WATCH...BUT IT MAY NEED TO BE EXPANDED IN
NEXT FORECAST PACKAGE. ONLY MINOR CHANGES MADE TO TEMPERATURES.
&&
.SHORT TERM /SATURDAY THROUGH MONDAY/...
ISSUED AT 353 PM EDT FRI MAY 31 2013
FORECAST CHALLENGES REMAIN ON HEAVY RAIN AND SEVERE WEATHER
POTENTIAL THROUGH SATURDAY NIGHT AS THE COLD FRONT TRACKS SLOWLY
THROUGH THE REGION.
POTENTIAL FOR A SCENARIO SIMILAR TO THIS MORNING TO PLAY OUT
SATURDAY MORNING AS REGION MAY RESIDE UNDERNEATH A THICK CLOUD
CANOPY WITHIN A STABLE ENVIRONMENT IN WAKE OF OVERNIGHT CONVECTION.
THAT PRESENTS CHALLENGES ONCE AGAIN AS TO WHETHER ANY SUBSTANTIAL
HEATING CAN TAKE PLACE THROUGHOUT THE DAY AND ULTIMATELY HOW
UNSTABLE THE AIRMASS CAN GET BY AFTERNOON. THE UPPER LEVEL DYNAMICS
ARE ARGUABLY BETTER WITH CENTRAL INDIANA REMAINING IN THE RIGHT REAR
QUAD OF THE 100KT UPPER JET WITH UPPER DIFFLUENCE AHEAD OF THE WAVE
ALOFT ENHANCING CONVECTIVE DEVELOPMENT. ADDITIONALLY...LOW LEVEL JET
WILL PERSIST ACROSS THE REGION ALL DAY WITH PRECIP WATER VALUES
REMAINING ABOVE 1.50-1.75 IN. THE QUESTION MARK AGAIN IS WHETHER
INSTABILITY WILL BE HAMPERED BASED ON CLOUD COVER AND ADDITIONAL
CONVECTIVE DEVELOPMENT AS THE DAY PROGRESSES. WHILE ISOLATED
DAMAGING WINDS FROM STORMS CANNOT BE RULED OUT...CONFIDENCE REMAINS
LOW IN A LARGER SCALE SEVERE WEATHER EVENT SATURDAY AFTERNOON AND
EVENING BASED ON FACTORS MENTIONED ABOVE.
AT THIS POINT...CONCERN IS ONCE AGAIN GREATER TOWARDS HEAVY RAINFALL
WITH DEEP MOISTURE REMAINING AND THE PRESENCE OF THE LOW LEVEL JET
AND SUBSEQUENT CONVERGENCE THROUGH THE BOUNDARY LAYER. COULD EASILY
SEE REPEATED ROUNDS OF STORMS THROUGHOUT THE DAY OR POSSIBLY ANOTHER
MCS LATER IN THE AFTERNOON AND EVENING AS THE UPPER LEVEL SUPPORT
MOVES IN FROM THE WEST. THE POTENTIAL FOR ANOTHER 1-2 INCHES OF
RAINFALL IS POSSIBLE INTO SATURDAY EVENING. DEPENDING ON HOW THE
CONVECTIVE PATTERN EVOLVES TONIGHT AND INTO SATURDAY...THE FLASH
FLOOD WATCH MAY NEED TO BE EXPANDED FURTHER EAST ACROSS THE FORECAST
AREA.
MODEL GUIDANCE CONSISTENT IN BRINGING THE UPPER TROUGH AXIS AND COLD
FRONT ACROSS THE REGION LATE SATURDAY NIGHT WITH WIDESPREAD RAINFALL
SHIFTING EAST. HAVE HELD ONTO SLIGHT CHANCE POPS SUNDAY AS A WEAK
SHORTWAVE ALOFT MOVES ACROSS THE OHIO VALLEY AND INTERACTS WITH THE
COLD POOL IN WAKE OF THE FRONTAL PASSAGE. EXPECT JUST ISOLATED
SHOWERS AS MODEL SOUNDINGS SHOW LIMITED INSTABILITY. REMAINDER OF
THE SHORT TERM WILL BE QUIET AS A LARGE AREA OF HIGH PRESSURE BUILDS
IN WITH COOLER AND MUCH DRIER AIR.
TEMPS...WITH THE EXPECTATION OF CLOUD COVER AND WIDESPREAD PRECIP
COVERAGE ON SATURDAY...FELT MAVMOS GUIDANCE TOO WARM WITH TEMPS IN
THE MID 80S. UNDERCUT BY SEVERAL DEGREES AND KEEPING MUCH OF THE
FORECAST AREA IN THE 70S. COOLER AIR EXPANDS INTO THE REGION SUNDAY
AND MONDAY WITH TEMPS FALLING BACK INTO THE UPPER 60S/LOWER 70S BY
MONDAY. MOS LOOKED REASONABLE FOR OVERNIGHT LOWS. COULD SEE SOME
UPPER 40S IN RURAL LOCALES NORTH OF INDY METRO MONDAY MORNING.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
ISSUED AT 256 PM EDT FRI MAY 31 2013
FAIRLY QUIET START TO THE LONG TERM PERIOD WITH BROAD SURFACE HIGH
PRESSURE OVER THE AREA. AN UPPER LEVEL SYSTEM WILL PUSH ACROSS THE
NORTHERN PLAINS...AND MAY BRING SOME THUNDERSTORMS TO THE AREA
BEGINNING AS EARLY AS WEDNESDAY NIGHT...WITH CHANCES INCREASING
TOWARD THE END OF THE WEEK. ALLBLEND HANDLED THIS WELL AND
REQUIRED FEW TWEAKS.
INITIALIZED TEMPERATURES WERE FAIRLY CLOSE...AGAIN WITH ONLY A FEW
MINOR TWEAKS REQUIRED. SHOULD SEE A SLIGHT WARMING TREND THROUGH
THE WEEK...WITH TEMPERATURES IN THE 80S MAKING A RETURN TO THE
AREA LATE IN THE WEEK.
&&
.AVIATION /DISCUSSION FOR 010300Z TAF ISSUANCE/...
ISSUED AT 1030 PM EDT FRI MAY 31 2013
TIMING OF LINE STILL LOOKS PRETTY GOOD...WITH ARRIVAL AT KLAF 4-5Z
AND KHUF SIMILAR. KIND AND KBMG AROUND 6-7Z. SOME CELLS AHEAD OF THE
LINE AS WELL SO INCLUDED AN HOUR OR TWO OF VCTS BEFORE ARRIVAL OF
LINE. PREVIOUS DISCUSSION FOLLOWS...
SOME MVFR CLOUDS OVER THE SITES CURRENTLY BUT THESE SHOULD LESSEN
WITH SUNSET AND VFR SHOULD BE THE RULE FOR A COUPLE OF HOURS. A LINE
OF THUNDERSTORMS CURRENTLY OVER WESTERN ILLINOIS WILL MOVE INTO THE
AREA STARTING AROUND 3-4Z OR SO AT KLAF AND THEN OVERSPREAD THE
OTHER SITES WITHIN A FEW HOURS. HRRR SHOWS THESE STORMS HANGING
AROUND THE SITES FOR SEVERAL HOURS AND NOT REALLY MOVING OFF TO THE
EAST UNTIL AFTER 12Z SATURDAY. WITH GRIDDED FORECAST ALSO SHOWING
LIKELY OR GREAT THUNDER CHANCES WILL GO WITH PREVAILING THUNDER FROM
ARRIVAL THROUGH MORNING. AFTER THAT WILL INCLUDE A PROB30 WITH GRIDS
STILL SHOWING LIKELY OR GREATER THUNDER CHANCES BUT THE EXPECTATION
THAT THERE WILL BE SOME SORT OF LULL IN THE MORNING BEFORE
THUNDERSTORMS FIRE UP AGAIN IN THE AFTERNOON. THUS WITH VERY HIGH
POPS AND THOUGHT THAT THUNDER WILL REFIRE IN THE AFTERNOON BROUGHT
PREVAILING THUNDER BACK IN AFTER 18Z. FAIRLY UNCERTAIN ABOUT WIND
GUSTS THROUGH THE OVERNIGHT. THINK THEY WILL NOT BE CONSTANT BUT
SHOULD PICK BACK UP IN/AROUND THUNDERSTORMS SO WILL ALLOW THESE TO
BE PREVAILING FOR MUCH OF THE NIGHT AS WELL. MAY DROP OFF IN THE
MORNING BEFORE PICKING BACK UP WITH GUSTS OF 20-25 KTS OUT OF THE
SOUTHWEST AGAIN IN THE AFTERNOON.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH MIDNIGHT THROUGH SUNDAY MORNING FOR
INZ028-029-035-036-043>045-051>053-060-061-067>069.
&&
$$
SYNOPSIS...RYAN
NEAR TERM...JH
SHORT TERM...RYAN
LONG TERM....NIELD
AVIATION...CP
VISIT US AT HTTP://WWW.WEATHER.GOV/IND
FOLLOW US ON TWITTER AND YOUTUBE AT:
WWW.TWITTER.COM/NWSINDIANAPOLIS
WWW.YOUTUBE.COM/NWSINDIANAPOLIS
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1010 PM EDT FRI MAY 31 2013
.UPDATE...
NEAR TERM FOR THE REST OF TONIGHT HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 353 PM EDT FRI MAY 31 2013
SEVERAL ROUNDS OF SHOWERS AND THUNDERSTORMS WILL IMPACT CENTRAL
INDIANA AS A SLOW MOVING COLD FRONT APPROACHES. THE FRONT WILL MOVE
THROUGH THE REGION SATURDAY NIGHT WITH COOLER AND MUCH DRIER AIR
SPREADING IN WITH HIGH PRESSURE FOR THE FIRST HALF OF THE WORK WEEK.
CHANCES FOR THUNDERSTORMS WILL RETURN THURSDAY AND FRIDAY AS A COLD
FRONT MOVES INTO THE REGION.
&&
.NEAR TERM /REST OF TONIGHT/...
ISSUED AT 1010 PM EDT FRI MAY 31 2013
A FEW THUNDERSTORMS WILL BRUSH NORTHERN CARROLL AND POSSIBLY HOWARD
COUNTY IN THE NEXT HOUR. OTHERWISE...THERE WILL BE A TEMPORARY LULL
IN THUNDERSTORMS ACROSS OUR REGION UNTIL AREA OF STRONG STORMS OVER
WESTERN ILLINOIS AND MISSOUR MOVE INTO WESTERN INDIANA BY 06Z.
THERE MAY BE SEVERAL HOURS OF SEVERE STORMS OVER WESTERN HALF OF OUR
REGION...THEN SEVERE THREAT WILL LESSEN AS STORMS MOVE INTO LESS
UNSTABLE AIR FARTHER EAST.
OF MORE CONCERN WILL BE HEAVY RAIN THREAT AS THUNDERSTORMS TRAIN
ACROSS EAST CENTRAL MISSOURI...SOUTHERN ILLINOIS INTO SOUTHWEST
PORTIONS OF OUR REGION. QPF AMOUNTS OF ONE TO TWO INCHES POSSIBLE
IN SOME AREAS WITH MORE RAIN OCCURRING SATURDAY. DID NOT MAKE ANY
CHANGES TO FLASH FLOOD WATCH...BUT IT MAY NEED TO BE EXPANDED IN
NEXT FORECAST PACKAGE. ONLY MINOR CHANGES MADE TO TEMPERATURES.
&&
.SHORT TERM /SATURDAY THROUGH MONDAY/...
ISSUED AT 353 PM EDT FRI MAY 31 2013
FORECAST CHALLENGES REMAIN ON HEAVY RAIN AND SEVERE WEATHER
POTENTIAL THROUGH SATURDAY NIGHT AS THE COLD FRONT TRACKS SLOWLY
THROUGH THE REGION.
POTENTIAL FOR A SCENARIO SIMILAR TO THIS MORNING TO PLAY OUT
SATURDAY MORNING AS REGION MAY RESIDE UNDERNEATH A THICK CLOUD
CANOPY WITHIN A STABLE ENVIRONMENT IN WAKE OF OVERNIGHT CONVECTION.
THAT PRESENTS CHALLENGES ONCE AGAIN AS TO WHETHER ANY SUBSTANTIAL
HEATING CAN TAKE PLACE THROUGHOUT THE DAY AND ULTIMATELY HOW
UNSTABLE THE AIRMASS CAN GET BY AFTERNOON. THE UPPER LEVEL DYNAMICS
ARE ARGUABLY BETTER WITH CENTRAL INDIANA REMAINING IN THE RIGHT REAR
QUAD OF THE 100KT UPPER JET WITH UPPER DIFFLUENCE AHEAD OF THE WAVE
ALOFT ENHANCING CONVECTIVE DEVELOPMENT. ADDITIONALLY...LOW LEVEL JET
WILL PERSIST ACROSS THE REGION ALL DAY WITH PRECIP WATER VALUES
REMAINING ABOVE 1.50-1.75 IN. THE QUESTION MARK AGAIN IS WHETHER
INSTABILITY WILL BE HAMPERED BASED ON CLOUD COVER AND ADDITIONAL
CONVECTIVE DEVELOPMENT AS THE DAY PROGRESSES. WHILE ISOLATED
DAMAGING WINDS FROM STORMS CANNOT BE RULED OUT...CONFIDENCE REMAINS
LOW IN A LARGER SCALE SEVERE WEATHER EVENT SATURDAY AFTERNOON AND
EVENING BASED ON FACTORS MENTIONED ABOVE.
AT THIS POINT...CONCERN IS ONCE AGAIN GREATER TOWARDS HEAVY RAINFALL
WITH DEEP MOISTURE REMAINING AND THE PRESENCE OF THE LOW LEVEL JET
AND SUBSEQUENT CONVERGENCE THROUGH THE BOUNDARY LAYER. COULD EASILY
SEE REPEATED ROUNDS OF STORMS THROUGHOUT THE DAY OR POSSIBLY ANOTHER
MCS LATER IN THE AFTERNOON AND EVENING AS THE UPPER LEVEL SUPPORT
MOVES IN FROM THE WEST. THE POTENTIAL FOR ANOTHER 1-2 INCHES OF
RAINFALL IS POSSIBLE INTO SATURDAY EVENING. DEPENDING ON HOW THE
CONVECTIVE PATTERN EVOLVES TONIGHT AND INTO SATURDAY...THE FLASH
FLOOD WATCH MAY NEED TO BE EXPANDED FURTHER EAST ACROSS THE FORECAST
AREA.
MODEL GUIDANCE CONSISTENT IN BRINGING THE UPPER TROUGH AXIS AND COLD
FRONT ACROSS THE REGION LATE SATURDAY NIGHT WITH WIDESPREAD RAINFALL
SHIFTING EAST. HAVE HELD ONTO SLIGHT CHANCE POPS SUNDAY AS A WEAK
SHORTWAVE ALOFT MOVES ACROSS THE OHIO VALLEY AND INTERACTS WITH THE
COLD POOL IN WAKE OF THE FRONTAL PASSAGE. EXPECT JUST ISOLATED
SHOWERS AS MODEL SOUNDINGS SHOW LIMITED INSTABILITY. REMAINDER OF
THE SHORT TERM WILL BE QUIET AS A LARGE AREA OF HIGH PRESSURE BUILDS
IN WITH COOLER AND MUCH DRIER AIR.
TEMPS...WITH THE EXPECTATION OF CLOUD COVER AND WIDESPREAD PRECIP
COVERAGE ON SATURDAY...FELT MAVMOS GUIDANCE TOO WARM WITH TEMPS IN
THE MID 80S. UNDERCUT BY SEVERAL DEGREES AND KEEPING MUCH OF THE
FORECAST AREA IN THE 70S. COOLER AIR EXPANDS INTO THE REGION SUNDAY
AND MONDAY WITH TEMPS FALLING BACK INTO THE UPPER 60S/LOWER 70S BY
MONDAY. MOS LOOKED REASONABLE FOR OVERNIGHT LOWS. COULD SEE SOME
UPPER 40S IN RURAL LOCALES NORTH OF INDY METRO MONDAY MORNING.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
ISSUED AT 256 PM EDT FRI MAY 31 2013
FAIRLY QUIET START TO THE LONG TERM PERIOD WITH BROAD SURFACE HIGH
PRESSURE OVER THE AREA. AN UPPER LEVEL SYSTEM WILL PUSH ACROSS THE
NORTHERN PLAINS...AND MAY BRING SOME THUNDERSTORMS TO THE AREA
BEGINNING AS EARLY AS WEDNESDAY NIGHT...WITH CHANCES INCREASING
TOWARD THE END OF THE WEEK. ALLBLEND HANDLED THIS WELL AND
REQUIRED FEW TWEAKS.
INITIALIZED TEMPERATURES WERE FAIRLY CLOSE...AGAIN WITH ONLY A FEW
MINOR TWEAKS REQUIRED. SHOULD SEE A SLIGHT WARMING TREND THROUGH
THE WEEK...WITH TEMPERATURES IN THE 80S MAKING A RETURN TO THE
AREA LATE IN THE WEEK.
&&
.AVIATION /DISCUSSION FOR 010000Z TAF ISSUANCE/...
ISSUED AT 703 PM EDT FRI MAY 31 2013
SOME MVFR CLOUDS OVER THE SITES CURRENTLY BUT THESE SHOULD LESSEN
WITH SUNSET AND VFR SHOULD BE THE RULE FOR A COUPLE OF HOURS. A LINE
OF THUNDERSTORMS CURRENTLY OVER WESTERN ILLINOIS WILL MOVE INTO THE
AREA STARTING AROUND 3-4Z OR SO AT KLAF AND THEN OVERSPREAD THE
OTHER SITES WITHIN A FEW HOURS. HRRR SHOWS THESE STORMS HANGING
AROUND THE SITES FOR SEVERAL HOURS AND NOT REALLY MOVING OFF TO THE
EAST UNTIL AFTER 12Z SATURDAY. WITH GRIDDED FORECAST ALSO SHOWING
LIKELY OR GREAT THUNDER CHANCES WILL GO WITH PREVAILING THUNDER FROM
ARRIVAL THROUGH MORNING. AFTER THAT WILL INCLUDE A PROB30 WITH GRIDS
STILL SHOWING LIKELY OR GREATER THUNDER CHANCES BUT THE EXPECTATION
THAT THERE WILL BE SOME SORT OF LULL IN THE MORNING BEFORE
THUNDERSTORMS FIRE UP AGAIN IN THE AFTERNOON. THUS WITH VERY HIGH
POPS AND THOUGHT THAT THUNDER WILL REFIRE IN THE AFTERNOON BROUGHT
PREVAILING THUNDER BACK IN AFTER 18Z. FAIRLY UNCERTAIN ABOUT WIND
GUSTS THROUGH THE OVERNIGHT. THINK THEY WILL NOT BE CONSTANT BUT
SHOULD PICK BACK UP IN/AROUND THUNDERSTORMS SO WILL ALLOW THESE TO
BE PREVAILING FOR MUCH OF THE NIGHT AS WELL. MAY DROP OFF IN THE
MORNING BEFORE PICKING BACK UP WITH GUSTS OF 20-25 KTS OUT OF THE
SOUTHWEST AGAIN IN THE AFTERNOON.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH MIDNIGHT THROUGH SUNDAY MORNING FOR
INZ028-029-035-036-043>045-051>053-060-061-067>069.
&&
$$
SYNOPSIS...RYAN
NEAR TERM...JH
SHORT TERM...RYAN
LONG TERM....NIELD
AVIATION...CP
VISIT US AT HTTP://WWW.WEATHER.GOV/IND
FOLLOW US ON TWITTER AND YOUTUBE AT:
WWW.TWITTER.COM/NWSINDIANAPOLIS
WWW.YOUTUBE.COM/NWSINDIANAPOLIS
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
740 PM EDT FRI MAY 31 2013
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW
&&
.SYNOPSIS...
ISSUED AT 353 PM EDT FRI MAY 31 2013
SEVERAL ROUNDS OF SHOWERS AND THUNDERSTORMS WILL IMPACT CENTRAL
INDIANA AS A SLOW MOVING COLD FRONT APPROACHES. THE FRONT WILL MOVE
THROUGH THE REGION SATURDAY NIGHT WITH COOLER AND MUCH DRIER AIR
SPREADING IN WITH HIGH PRESSURE FOR THE FIRST HALF OF THE WORK WEEK.
CHANCES FOR THUNDERSTORMS WILL RETURN THURSDAY AND FRIDAY AS A COLD
FRONT MOVES INTO THE REGION.
&&
.NEAR TERM /TONIGHT/...
ISSUED AT 740 PM EDT FRI MAY 31 2013
AREA OF THUNDERSTORMS MOVING INTO NORTHWEST INDIANA MAY BRUSH FAR
NORTHERN CARROLL AND HOWARD COUNTIES. OTHERWISE...EXPECT A LULL IN
THUNDERSTORMS UNTIL AFTER MIDNIGHT. AREA OF THUNDERSTORMS OVER
MISSOURI WILL BE OUR NEXT CONCERN. RAPID REFRESH INDICATES NUMEROUS
THUNDERSTORMS SPREADING INTO WESTERN INDIANA AROUND 06Z AND OVER THE
REST OF OUR AREA OVERNIGHT. BECAUSE OF THE SLOWER ONSET OF
PRECIPITATION DELAYED BEGINNING OF FLASH FLOOD WATCH UNTIL MIDNIGHT.
EXPECT ROBUST CONVECTIVE DEVELOPMENT OVER THE OZARKS BACK INTO
OKLAHOMA AS THE AFTERNOON WEARS ON...WITH ADDITIONAL DEVELOPMENT
LIKELY EXPANDING NORTHEAST INTO THE MISSISSIPPI VALLEY AND INTO
ILLINOIS AS INCREASED BL SHEAR AND FORCING ALOFT COURTESY OF AN
INTENSIFYING UPPER JET. NOCTURNAL LOW LEVEL JET WILL ONCE AGAIN
DEVELOP AND NOSE INTO THE REGION AFTER NIGHTFALL AND COMBINED WITH
THE BETTER UPPER LEVEL FORCING APPROACHING FROM THE WEST AND
WHATEVER INSTABILITY CAN BE GLEANED OVER THE NEXT SEVERAL
HOURS...ANTICIPATE CONVECTION TO THE WEST TO COALESCE INTO AN MCS
AND DROP SOUTHEAST INTO THE FORECAST AREA OVERNIGHT. LACK OF MORE
SUBSTANTIAL INSTABILITY HAS RAISED DOUBTS AS TO WHETHER STORMS WILL
BE SEVERE AS THEY ENTER THE FORECAST AREA. FEELING AT THIS POINT IS
THAT STORMS WILL BE STRONG WITH POTENTIALLY AN ISOLATED RISK FOR
DAMAGING WINDS. OTHERWISE...THE PRIMARY CONCERN WILL BE THE HEAVY
RAIN.
HEAVY RAIN AND FLOODING IS BECOMING A GREATER CONCERN...ESPECIALLY
ACROSS THE WABASH VALLEY WHICH EXPERIENCED 1 TO 2 INCHES OF RAIN
LAST NIGHT AND EARLY THIS MORNING. PRECIPITABLE WATER VALUES IN
EXCESS OF 1.75 INCHES ARE ANTICIPATED OVERNIGHT WITH A DEEP
SATURATED COLUMN EXTENDING UP TO NEAR 650MB. IN ADDITION...BROAD
SOUTHWEST FLOW ALOFT AND POTENTIAL FOR AN AXIS OF DEEP CONVERGENCE
UP TO ABOUT 700MB ALL SUPPORT POTENTIAL FOR TORRENTIAL RAINFALL AND
EFFICIENT RATES LATE TONIGHT. COULD SEE AMOUNTS IN EXCESS OF 1-2
INCHES OVER FAR WESTERN FORECAST AREA. WILL BE INTRODUCING A FLASH
FLOOD WATCH FOR THE WABASH VALLEY THROUGH 12Z SUNDAY BECAUSE OF
THESE CONCERNS. WILL RAISE POPS TO LIKELY OVER THE EAST AND
CATEGORICAL OVER THE WEST LATE TONIGHT.
TEMPS...MOS GUIDANCE LOOKS REASONABLE AS LOW TEMPS WILL ONLY FALL
INTO THE UPPER 60S TO NEAR 70 WITH SATURATED LOWER LEVELS.
&&
.SHORT TERM /SATURDAY THROUGH MONDAY/...
ISSUED AT 353 PM EDT FRI MAY 31 2013
FORECAST CHALLENGES REMAIN ON HEAVY RAIN AND SEVERE WEATHER
POTENTIAL THROUGH SATURDAY NIGHT AS THE COLD FRONT TRACKS SLOWLY
THROUGH THE REGION.
POTENTIAL FOR A SCENARIO SIMILAR TO THIS MORNING TO PLAY OUT
SATURDAY MORNING AS REGION MAY RESIDE UNDERNEATH A THICK CLOUD
CANOPY WITHIN A STABLE ENVIRONMENT IN WAKE OF OVERNIGHT CONVECTION.
THAT PRESENTS CHALLENGES ONCE AGAIN AS TO WHETHER ANY SUBSTANTIAL
HEATING CAN TAKE PLACE THROUGHOUT THE DAY AND ULTIMATELY HOW
UNSTABLE THE AIRMASS CAN GET BY AFTERNOON. THE UPPER LEVEL DYNAMICS
ARE ARGUABLY BETTER WITH CENTRAL INDIANA REMAINING IN THE RIGHT REAR
QUAD OF THE 100KT UPPER JET WITH UPPER DIFFLUENCE AHEAD OF THE WAVE
ALOFT ENHANCING CONVECTIVE DEVELOPMENT. ADDITIONALLY...LOW LEVEL JET
WILL PERSIST ACROSS THE REGION ALL DAY WITH PRECIP WATER VALUES
REMAINING ABOVE 1.50-1.75 IN. THE QUESTION MARK AGAIN IS WHETHER
INSTABILITY WILL BE HAMPERED BASED ON CLOUD COVER AND ADDITIONAL
CONVECTIVE DEVELOPMENT AS THE DAY PROGRESSES. WHILE ISOLATED
DAMAGING WINDS FROM STORMS CANNOT BE RULED OUT...CONFIDENCE REMAINS
LOW IN A LARGER SCALE SEVERE WEATHER EVENT SATURDAY AFTERNOON AND
EVENING BASED ON FACTORS MENTIONED ABOVE.
AT THIS POINT...CONCERN IS ONCE AGAIN GREATER TOWARDS HEAVY RAINFALL
WITH DEEP MOISTURE REMAINING AND THE PRESENCE OF THE LOW LEVEL JET
AND SUBSEQUENT CONVERGENCE THROUGH THE BOUNDARY LAYER. COULD EASILY
SEE REPEATED ROUNDS OF STORMS THROUGHOUT THE DAY OR POSSIBLY ANOTHER
MCS LATER IN THE AFTERNOON AND EVENING AS THE UPPER LEVEL SUPPORT
MOVES IN FROM THE WEST. THE POTENTIAL FOR ANOTHER 1-2 INCHES OF
RAINFALL IS POSSIBLE INTO SATURDAY EVENING. DEPENDING ON HOW THE
CONVECTIVE PATTERN EVOLVES TONIGHT AND INTO SATURDAY...THE FLASH
FLOOD WATCH MAY NEED TO BE EXPANDED FURTHER EAST ACROSS THE FORECAST
AREA.
MODEL GUIDANCE CONSISTENT IN BRINGING THE UPPER TROUGH AXIS AND COLD
FRONT ACROSS THE REGION LATE SATURDAY NIGHT WITH WIDESPREAD RAINFALL
SHIFTING EAST. HAVE HELD ONTO SLIGHT CHANCE POPS SUNDAY AS A WEAK
SHORTWAVE ALOFT MOVES ACROSS THE OHIO VALLEY AND INTERACTS WITH THE
COLD POOL IN WAKE OF THE FRONTAL PASSAGE. EXPECT JUST ISOLATED
SHOWERS AS MODEL SOUNDINGS SHOW LIMITED INSTABILITY. REMAINDER OF
THE SHORT TERM WILL BE QUIET AS A LARGE AREA OF HIGH PRESSURE BUILDS
IN WITH COOLER AND MUCH DRIER AIR.
TEMPS...WITH THE EXPECTATION OF CLOUD COVER AND WIDESPREAD PRECIP
COVERAGE ON SATURDAY...FELT MAVMOS GUIDANCE TOO WARM WITH TEMPS IN
THE MID 80S. UNDERCUT BY SEVERAL DEGREES AND KEEPING MUCH OF THE
FORECAST AREA IN THE 70S. COOLER AIR EXPANDS INTO THE REGION SUNDAY
AND MONDAY WITH TEMPS FALLING BACK INTO THE UPPER 60S/LOWER 70S BY
MONDAY. MOS LOOKED REASONABLE FOR OVERNIGHT LOWS. COULD SEE SOME
UPPER 40S IN RURAL LOCALES NORTH OF INDY METRO MONDAY MORNING.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
ISSUED AT 256 PM EDT FRI MAY 31 2013
FAIRLY QUIET START TO THE LONG TERM PERIOD WITH BROAD SURFACE HIGH
PRESSURE OVER THE AREA. AN UPPER LEVEL SYSTEM WILL PUSH ACROSS THE
NORTHERN PLAINS...AND MAY BRING SOME THUNDERSTORMS TO THE AREA
BEGINNING AS EARLY AS WEDNESDAY NIGHT...WITH CHANCES INCREASING
TOWARD THE END OF THE WEEK. ALLBLEND HANDLED THIS WELL AND
REQUIRED FEW TWEAKS.
INITIALIZED TEMPERATURES WERE FAIRLY CLOSE...AGAIN WITH ONLY A FEW
MINOR TWEAKS REQUIRED. SHOULD SEE A SLIGHT WARMING TREND THROUGH
THE WEEK...WITH TEMPERATURES IN THE 80S MAKING A RETURN TO THE
AREA LATE IN THE WEEK.
&&
.AVIATION /DISCUSSION FOR 010000Z TAF ISSUANCE/...
ISSUED AT 703 PM EDT FRI MAY 31 2013
SOME MVFR CLOUDS OVER THE SITES CURRENTLY BUT THESE SHOULD LESSEN
WITH SUNSET AND VFR SHOULD BE THE RULE FOR A COUPLE OF HOURS. A LINE
OF THUNDERSTORMS CURRENTLY OVER WESTERN ILLINOIS WILL MOVE INTO THE
AREA STARTING AROUND 3-4Z OR SO AT KLAF AND THEN OVERSPREAD THE
OTHER SITES WITHIN A FEW HOURS. HRRR SHOWS THESE STORMS HANGING
AROUND THE SITES FOR SEVERAL HOURS AND NOT REALLY MOVING OFF TO THE
EAST UNTIL AFTER 12Z SATURDAY. WITH GRIDDED FORECAST ALSO SHOWING
LIKELY OR GREAT THUNDER CHANCES WILL GO WITH PREVAILING THUNDER FROM
ARRIVAL THROUGH MORNING. AFTER THAT WILL INCLUDE A PROB30 WITH GRIDS
STILL SHOWING LIKELY OR GREATER THUNDER CHANCES BUT THE EXPECTATION
THAT THERE WILL BE SOME SORT OF LULL IN THE MORNING BEFORE
THUNDERSTORMS FIRE UP AGAIN IN THE AFTERNOON. THUS WITH VERY HIGH
POPS AND THOUGHT THAT THUNDER WILL REFIRE IN THE AFTERNOON BROUGHT
PREVAILING THUNDER BACK IN AFTER 18Z. FAIRLY UNCERTAIN ABOUT WIND
GUSTS THROUGH THE OVERNIGHT. THINK THEY WILL NOT BE CONSTANT BUT
SHOULD PICK BACK UP IN/AROUND THUNDERSTORMS SO WILL ALLOW THESE TO
BE PREVAILING FOR MUCH OF THE NIGHT AS WELL. MAY DROP OFF IN THE
MORNING BEFORE PICKING BACK UP WITH GUSTS OF 20-25 KTS OUT OF THE
SOUTHWEST AGAIN IN THE AFTERNOON.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH MIDNIGHT THROUGH SUNDAY MORNING FOR
INZ028-029-035-036-043>045-051>053-060-061-067>069.
&&
$$
SYNOPSIS...RYAN
NEAR TERM...RYAN/JH
SHORT TERM...RYAN
LONG TERM....NIELD
AVIATION...CP
VISIT US AT HTTP://WWW.WEATHER.GOV/IND
FOLLOW US ON TWITTER AND YOUTUBE AT:
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WWW.YOUTUBE.COM/NWSINDIANAPOLIS
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
300 PM EDT THU MAY 30 2013
.SYNOPSIS...
ISSUED AT 1038 AM EDT THU MAY 30 2013
A WEAK SYSTEM MOVING INTO THE REGION COULD SPAWN A FEW SHOWERS OR
ISOLATED STORMS FROM MIDDAY INTO THIS EVENING. TEMPERATURES WILL
RISE INTO THE MID TO UPPER 80S. WHILE THE CHANCES FOR SHOWERS AND
THUNDERSTORMS WILL INCREASE LATER THIS WEEKEND...THE CHANCE OF
SHOWERS AND A FEW NON SEVERE STORMS CAN NOT BE RULED OUT
OVERNIGHT. LOWS TONIGHT WILL BE IN THE UPPER 60S.
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 300 PM EDT THU MAY 30 2013
THE MAIN FOCUS THIS PERIOD IS ON CONVECTIVE POTENTIAL/EVOLUTION.
SYNOPTICALLY...A CLOSED LOW WILL MEANDER SLOWLY EAST ACROSS THE
NORTHERN PLAINS WITH DEEP/MOIST CYCLONICALLY CURVED SOUTHWEST FLOW
IN PLACE FROM THE SOUTHERN PLAINS NORTHEAST INTO THE GREAT LAKES
REGION. AT THE SURFACE THE PRIMARY SFC FRONT FRONT WILL BE DRAPED
FROM THE UPPER MIDWEST SOUTHWEST INTO THE SOUTHERN PLAINS WITH A
MOIST/HUMID/UNSTABLE AIRMASS OUT AHEAD OF THIS.
THE REMAINDER OF THE AFTERNOON INTO EARLY THIS EVENING...
19Z REGIONAL RADAR MOSAIC SHOWING SCATTERED CONVECTION FIRING ACROSS
MUCH OF ILLINOIS IN A ZONE OF WEAK MOISTURE CONVERGENCE ON THE
EASTERN FLANK OF A CONVECTIVELY ENHANCED/INDUCED SHORTWAVE LIFTING
INTO WEST-CENTRAL ILLINOIS...WITH ISOLATED CONVECTION STARTING TO
POP ACROSS THE LOCAL AREA. LATEST RAP ANALYSIS SHOWS 1500-2000
J/KG OF MLCAPE ACROSS THE AREA WITH LITTLE/NO CIN. EXPECT ISOLATED
TO SCATTERED CONVECTION TO MAINLY IMPACT AREAS ALONG AND WEST OF
INTERSTATE 69 INTO THE EARLY EVENING AS WEAK FORCING AND CONTINUED
LOW/MID LEVEL THETA-E ADVECTION ADVECTS OVER THIS AREA. MARGINAL
20-25 KNOTS OF DEEP LAYER EFFECTIVE SHEAR A DEFINITE LIMITING
FACTOR FOR ORGANIZATION AND ISOLATED SEVERE STORMS...ALTHOUGH
CANNOT RULE OUT AN ISOLATED DAMAGING WIND/HAIL THREAT IF ANY
MULTICELL CLUSTERS/SMALL LINE SEGMENTS TAKE SHAPE.
LARGE SCALE UPPER SUPPORT WILL INCREASE TONIGHT INTO FRIDAY MORNING
AS A MORE PRONOUNCED MID LEVEL SHORTWAVE TROUGH NOW EJECTING INTO
THE CENTRAL PLAINS ON THE NOSE OF AN UPPER JET TRANSLATES NORTHEAST
INTO THE WESTERN/NORTHERN GREAT LAKES. THIS SUPPORTS THE IDEA OF
LATEST HI-RES GUIDANCE IN MAINTAINING A WEAKENING MESOSCALE
CONVECTIVE SYSTEM (ACROSS CENTRAL IOWA INTO WESTERN MISSOURI AS OF
THIS WRITING) EAST INTO AT LEAST OUR WESTERN ZONES AFTER 05/06Z ISH.
MEAGER MID LEVEL LAPSE RATES COUPLED WITH DIURNAL COOLING SHOULD
ALLOW WHAT MIGHT BE A LINE OF SEVERE CONVECTION INTO ILLINOIS THIS
EVENING TO WEAKEN (FALL APART?) AS IT ATTEMPTS TO MAKE INTO THE
LOCAL AREA FROM WEST TO EAST OVERNIGHT...WITH SHOWERS/ISO THUNDER
POSSIBLY LINGERING INTO FRIDAY MORNING ALONG THE MCS/MCV RESIDUAL
OUTFLOW BOUNDARY. BUMPED UP POPS A BIT AFTER MIDNIGHT....HIGHEST
WEST.
SUBSIDENCE/AVA BEHIND THE MID LEVEL TROUGH AXIS LATER FRIDAY MORNING
INTO THE EARLY/MID AFTERNOON HOURS WITH ATMOSPHERE POSSIBLY WORKED
OVER FROM MORNING CLOUDS/SHOWERS SHOULD RESULT IN A LULL IN PCPN
ACROSS THE AREA DURING THIS TIME. ALTHOUGH RETAINED LOW 20-30
PERCENT POPS BTW 15-21Z AS RENEWED CONVECTION COULD FORM ALONG THE
RESIDUAL OUTFLOW BOUNDARY BY EARLY/MID AFTERNOON...BEST CHANCES
ACROSS OUR SOUTHEASTERN ZONES. CHANCES FOR ADDITIONAL
CONVECTION...POTENTIALLY SEVERE...BY LATE AFTERNOON AND EVENING
ARE DISCUSSED IN THE LONG TERM SECTION.
&&
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 300 PM EDT THU MAY 30 2013
POTENT SW AND ATTENDANT CLOSED LOW OVR SD IS XCPD TO OPEN FRI NIGHT
AND KICK EWD ACRS THE LAKES IN RESPONSE OF ARRIVAL OF UPSTREAM
KICKER INTO THE PACNW. AT THE SFC...PRONOUNCED SFC WAVE OVR SRN MN
SAT MORNING WILL EJECT EWD TO LK HURON BY SUN MORNING AS ASSOCD
TRAILING CDFNT SURGES EWD.
BEST LL MSTR FLUX/LL THETA-E RIDGING XCPD FRI EVENING W/AGAIN A
CONDITIONAL SVR THREAT PENDING SHRT TERM CONV EVOLUTION/MAINTAINANCE
INTO THE WRN LAKES FRI AFTN. OTRWS STG SFC CDFNT TO CROSS CWA SAT
AFTN/EVE W/STG FORCING FOR ASCENT WITHIN CONTD SIG LL MSTR PLUME AND
LIKELY MOST FVRBL WINDOW FOR SIG RAINFALL.
STG CAA FOLLOWS ON SUN W/RAPID NEWD ADVTN OF MID LVL DRYSLOT
UNDERNEATH MID LVL TROUGH PIVOTING THROUGH MI. GIVEN GENERAL 12Z
CONSENSUS SOLUTION WILL DROP LOW CHC POPS MOST AREAS SANS FAR SE.
DRY AND SEASONABLE WX XPCD THROUGH UNTIL THE END OF THE PD.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1217 PM EDT THU MAY 30 2013
MAINLY VFR THROUGH THE PERIOD WITH PRIMARY FOCUS ON CONVECTIVE
POTENTIAL THIS AFTERNOON AND EARLY EVENING. MODERATE INSTABILITY
THIS AFTERNOON COINCIDENT WITH CONTINUED LOW/MID LEVEL THETA-E
ADVECTION AND A SHORTWAVE LIFTING NORTHEAST INTO ILLINOIS SHOULD
ALLOW FOR A FEW SHOWERS/STORMS TO DEVELOP AROUND 19-20Z. KEPT THE
2 HOUR TEMPO TSRA/MVFR GROUP AT SBN WHERE BETTER CHANCES FOR
CONVECTION RESIDES. LESSER CHANCES AT FWA WHERE VCTS/VFR GROUP
ADDED BTW 20-01Z. SHOWER/STORM ACTIVITY SHOULD DIMINISH BTW 23-02Z
GIVEN LOSS OF HEATING AND WEAK FORCING...LEAVING MOST OF THE
EVENING DRY/VFR. CONFIDENCE BEYOND MIDNIGHT IS LOW AS A WEAKENING
UPSTREAM CONVECTIVE COMPLEX ACROSS MISSOURI/IOWA MAKES A RUN AT
THE GREAT LAKES. ADDED A VCSH MENTION AFTER 07Z AT SBN AS
WEAKENING LINE OF SHOWERS/STORMS MAY HOLD TOGETHER INTO NORTHWEST
INDIANA. RETAINED OPTIMISTIC DRY FCST AT FWA.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 9 PM EDT THIS EVENING FOR LMZ043-046.
&&
$$
SYNOPSIS...BENTLEY
SHORT TERM...STEINWEDEL
LONG TERM...T
AVIATION...STEINWEDEL
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AREA FORECAST DISCUSSION
NWS DES MOINES IA
350 PM CDT THU MAY 30 2013
.SHORT TERM.../TONIGHT /...
ISSUED AT 350 PM CDT THU MAY 30 2013
MAIN SHORTWAVE LIFTING THROUGH THE BASE OF THE UPPER LEVEL TROUGH
RESPONSIBLE FOR AREA OF SHOWERS AND THUNDERSTORMS ACROSS THE FAR
SOUTHEASTERN CWA. AS SHORTWAVE CONTINUES TO LIFT NORTHEAST THROUGH
THE EASTERN PORTION OF THE STATE...AREA OF SHOWERS/THUNDERSTORMS
WILL CONTINUE TO SHOVE EAST OUT OF THE CWA. LOOKING BACK TO THE
WEST...HAVE SOME ISOLATED WEAK CELLS DEVELOPING ACROSS CENTRAL
NE/KS. THIS ACTIVITY MAY APPROACH THE SOUTHWESTERN/SOUTHERN CWA BY
MID EVENING...BUT IS EXPECTED TO BE RELATIVELY WEAK WITH LESS THAN
1000 J/KG CAPE ON NAM/RAP SOUNDINGS. HRRR SEEMS TO BE GRASPING
CURRENT RADAR TRENDS CORRECTLY...SO KEPT POPS CLOSE TO THE HRRR
OUTPUT. THE WESTERN ACTIVITY IS MOSTLY DIURNALLY DRIVEN...SO EXPECT
IT TO DIMINISH TOWARD SUNSET. ANOTHER WAVE OF ENERGY TO ROUND THE
BASE OF THE UPPER LEVEL TROUGH TO APPROACH THE STATE LATE
TONIGHT...MAY ALLOW FOR SOME SHOWERS AND ISOLATED THUNDERSTORMS TO
DEVELOP TOWARD SUNRISE FRIDAY MORNING. THE DEEP MOISTURE THAT HAS
BEEN IN PLACE ACROSS THE STATE OVER THE PAST WEEK...IS BEGINNING TO
PUSH EAST WITH THE ADVANCEMENT OF A DRY LINE OVER CENTRAL
NE/KS...THEREFORE THE HEAVY RAIN THREAT WILL BE LESSENED WITH ANY
ACTIVITY THAT DEVELOPS LATE TONIGHT/EARLY FRIDAY MORNING.
.LONG TERM.../FRIDAY THROUGH THURSDAY/...
ISSUED AT 350 PM CDT THU MAY 30 2013
AN UPPER LEVEL LOW PRESSURE SYSTEM WILL REMAIN NEARLY STATIONARY
OVER THE DAKOTAS AND MINNESOTA FRIDAY AND FRIDAY NIGHT...BEFORE
MOVING EASTWARD ACROSS IOWA ON SATURDAY AND AWAY OVER THE GREAT
LAKES ON SATURDAY NIGHT. ON FRIDAY MORNING LOW LEVEL FLOW WILL
STILL BE FROM THE SOUTH SOUTHWEST AND AN APPROACHING SHORTWAVE
MOVING AROUND THE UPPER LOW SHOULD KICK OFF THUNDERSTORMS ACROSS
EASTERN KANSAS LATE TONIGHT THAT WILL MOVE ACROSS OUR SOUTHERN AND
EASTERN COUNTIES ON FRIDAY. HAVE INCREASED POPS INTO THE 70 TO 80
PERCENT RANGE IN OUR SOUTHEAST TO ACCOUNT FOR THIS...AND SEVERE
WEATHER WILL BE POSSIBLE IN THESE AREAS AS WELL. FRIDAY SHOULD BE
FAIRLY WARM ESPECIALLY IF SKIES ARE ABLE TO CLEAR ACROSS MUCH OF
THE CWA...AND HAVE RAISED FORECAST HIGHS A BIT EVEN INTO THE
LOWER 80S IN SOME AREAS.
BY FRIDAY EVENING THE DAYTIME STORMS WILL BE EXITING TO THE EAST
AHEAD OF A SURFACE TROUGH MOVING ACROSS THE AREA. WINDS BEHIND
THIS TROUGH WILL TURN TO WEST AND THEN NORTHWEST WITH COOLER AIR
FLOWING INTO THE AREA. IN ADDITION...AS THE UPPER LEVEL LOW
PRESSURE TROUGH MOVES ACROSS OUR AREA ON SATURDAY IT WILL BE
ACCOMPANIED BY THICK CLOUDS AND LIGHT SHOWERS MAKING FOR A GREY
AND DAMP DAY. NO THUNDERSTORMS ARE ANTICIPATED AND ANY RAINFALL
AMOUNTS WILL BE LIGHT. COVERAGE IS UNCERTAIN SO HAVE MAINTAINED
POPS BELOW 50 PERCENT...BUT THIS MAY NEED TO BE INCREASED LATER IN
A CLASSIC HIGH POP/LOW QPF SCENARIO. BY SUNDAY A SURFACE RIDGE
WILL BUILD IN MAKING FOR MOSTLY CLEAR AND DRY BUT COOL WEATHER
WITH LIGHT NORTH WINDS.
FROM SUNDAY NIGHT THROUGH THURSDAY THE 500 MB PATTERN WILL UNDERGO
AN EERILY SIMILAR EVOLUTION TO WHAT WE HAVE SEEN OVER THE LAST
SEVERAL DAYS...AS ANOTHER UPPER LOW MOVES INTO THE NORTHWESTERN
U.S. AND THEN ACROSS THE UPPER MIDWEST. THIS WILL RESULT IN
ANOTHER EXTENDED PERIOD OF THUNDERSTORM CHANCES FOR OUR AREA FROM
MONDAY NIGHT THROUGH THE END OF THE FORECAST PERIOD.
HOWEVER...UNLIKE THE SYSTEM OF THE PAST SEVERAL DAYS...THE 500 MB
LOW NEXT WEEK WILL NOT HAVE AS MUCH LATITUDINAL EXTENT AND WILL BE
GENERALLY MORE PROGRESSIVE...MITIGATING SOMEWHAT THE POTENTIAL FOR
EXTENDED HEAVY RAINFALL. THE DETAILS OF THE RAINFALL FORECAST FOR
NEXT WEEK WILL BE IRONED OUT LATER...BUT AT LEAST THERE WILL BE
SEVERAL RELATIVELY DRY DAYS THIS WEEKEND TO ALLOW CURRENT FLOOD
WATERS TO SUBSIDE...AND RAINFALL AMOUNTS NEXT WEEK SHOULD BE
CONSIDERABLY LIGHTER IN MOST AREAS WITH THE PRIMARY CHANCES
LIMITED TO THE MONDAY NIGHT...TUESDAY...AND TUESDAY NIGHT PERIODS.
&&
.AVIATION...30/18Z
ISSUED AT 103 PM CDT THU MAY 30 2013
AREA OF SHOWERS AND MVFR CIGS ACROSS THE AREA...SHOULD CONTINUE TO
SLIGHTLY MOVE NORTH AND EAST THROUGH THE AFTERNOON. CHANCES FOR
THUNDERSTORMS TO INCREASE ESPECIALLY AT THE EASTERN TAF SITES THIS
AFTERNOON INTO EARLY EVENING. MAJORITY OF PRECIPITATION CHANCES
EXPECTED TO END ACROSS THE CWA BY MID EVENING...WITH POSSIBLY HIGH
MVFR TO LOW VFR CIGS EXPECTED OVERNIGHT. POSSIBILITY OF FOG
REDUCING VSBYS/CIGS LATE TONIGHT DUE TO ABUNDANT MOISTURE
AROUND...HOWEVER VERY UNCERTAIN SO HAVE NOT PLACED IN THE TAF AT
THIS TIME. GUSTY SOUTHERLY WINDS EXPECTED THROUGH THE PERIOD.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH THROUGH FRIDAY EVENING FOR SOUTHEAST BUTLER.
&&
$$
SHORT TERM...BEERENDS
LONG TERM...LEE
AVIATION...BEERENDS
AREA FORECAST DISCUSSION
NWS GOODLAND KS
538 PM MDT FRI MAY 31 2013
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 152 PM MDT FRI MAY 31 2013
EARLY AFTERNOON WV IMAGERY AND RAP H5 ANALYSIS SHOW LARGE SCALE
TROUGH STILL IN PLACE ACROSS NORTHERN PLAINS WITH CLOSED CENTER
OVER THE EASTERN DAKOTAS. A SERIES OF WEAK VORTICITY MAXIMA ARE
ROTATING AROUND THE WESTERN EXTENT OF THE UPPER LOW PRODUCING
MID-HIGH CLOUDS ACROSS THE PLAINS. OVER THE SOUTHERN PART OF OUR CWA
STEEP LAPSE RATES ALONG A BAROCLINIC ZONE HAS LED TO DEVELOPMENT OF
HIGH BASED SHOWERS/VIRGA. WITH BASES GENERALLY AROUND 12KFT AND A
DEEP DRY LAYER BELOW THIS...IT IS UNLIKELY MUCH MORE THAN A FEW
SPRINKLES WILL REACH THE SURFACE WITH THIS ACTIVITY.
RED FLAG CONDITIONS AND GUSTY WINDS SHOULD CONTINUE THROUGH THE EARLY
EVENING PERIOD ACROSS NW HALF OF THE CWA. LIMITING FACTOR FOR RFW
CONTINUES TO BE FUELS...AND WITHOUT FURTHER INFORMATION IN THIS
REGARD I DECIDED AGAINST EXPANDING CURRENT WARNING. WINDS HAVE
OCCASIONALLY HIT ADVISORY CRITERIA IN THE NW...HOWEVER THESE
CONDITIONS HAVE BEEN SPORADIC...SO IVE LEANED AGAINST ISSUANCE OF
WIND ADVISORY.
TONIGHT A SHORTWAVE TROUGH WILL ROUND THE BASE OF THE LARGE SCALE
UPPER LOW WITH A COLD FRONT DROPPING SOUTH OVER OUR CWA (06 TO 09Z).
WHILE WINDS MAY DECREASE SOME AFTER SUNSET...THE LULL IN WINDS THIS
EVENING WILL BE SHORT LIVED BEFORE NEAR ADVISORY LEVEL WINDS
REDEVELOP AFTER MIDNIGHT AND CONTINUE THROUGH THE DAY SATURDAY
BEHIND THE FROPA. SOME GUIDANCE IS ALSO SHOWING BETTER MID LEVEL
MOISTURE WITH THIS UPPER LEVEL TROUGH ROTATING INTO THE
CWA...HOWEVER THE BEST LIFT IS OUTSIDE OUR CWA...AND MODELS NEVER
INITIATE SHOWERS OVER OUR CWA WITH DRY LOW LEVELS STILL IN PLACE.
OTHER THAN THICKENING CLOUD COVER...I AM NOT EXPECTING ANY PRECIP.
OVERNIGHT LOWS TONIGHT WILL DROP TO THE LOW 40S IN EASTERN COLORADO
TO THE LOW 50S IN NORTH CENTRAL KANSAS. CONSIDERING THE COOL NATURE
OF THE AIR MASS WE WOULD BE LOOKING AT MUCH COLDER TEMPS IF IT WASNT
FOR CLOUD COVER AND WINDS OVERNIGHT. HIGHS ON SATURDAY MAY STRUGGLE
TO REACH THE UPPER 60S/70F IF CLOUD COVER FAILS TO CLEAR BY THE
AFTERNOON AS CURRENTLY ADVERTISED.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 152 PM MDT FRI MAY 31 2013
FOR SATURDAY NIGHT THROUGH SUNDAY NIGHT...THE UPPER LEVEL RIDGE WILL
BEGIN TO MOVE OVER THE AREA SATURDAY NIGHT AS A SURFACE HIGH MOVES
INTO THE AREA. SUNDAY THE SURFACE HIGH WILL SLIDE EAST. AS IT DOES
SO A TIGHT PRESSURE GRADIENT WILL DEVELOP OVER THE AREA FROM WEST TO
EAST BEHIND THE EXITING SURFACE HIGH. WINDS WILL BREEZY BUT WILL
DECLINE BEFORE SUNSET AS TEMPERATURES COOL. SUNDAY EVENING AS THE UPPER
LEVEL RIDGE AXIS MOVES EAST OF THE AREA A SHORT WAVE TROUGH WILL
MOVE ACROSS THE AREA. POINT SOUNDINGS SHOW A VERY SMALL AMOUNT OF
ELEVATED INSTABILITY OVER THE SOUTHWEST PART OF THE AREA AS THE
SHORT WAVE MOVES THROUGH. AT THIS TIME WILL KEEP THE FORECAST DRY DUE
TO LOW CONFIDENCE THAT ANY STORMS WILL DEVELOP GIVEN THE ELEVATED
CAPE IS LESS THAN 200 J/KG...AND THE DEEP DRY LAYER EXTENDING UP TO
600MB OR SO WHICH WILL CAUSE ANY LIGHT RAIN THAT MAY DEVELOP TO
EVAPORATE.
MONDAY THROUGH FRIDAY AN UPPER LEVEL TROUGH WILL MOVE ACROSS THE
NORTHERN PLAINS. MODELS HAVE SHIFTED THE TRACK OF THE TROUGH
SLIGHTLY NORTH...BUT OVERALL THIS SEEMS TO HAVE LITTLE EFFECT ON
PRECIP. CHANCES FOR THE PERIOD. NUMEROUS SHORT WAVE TROUGHS THAT
EXTEND FROM THE MAIN FEATURE MOVE OVER THE AREA TROUGH THE PERIOD AS
THE TROUGH SLOWLY MOVES EAST OVER THE NORTHERN PLAINS. WITH EACH
SHORT WAVE TROUGH MOVING THROUGH THE AREA PRECIP. CHANCES WILL
RETURN.
TEMPERATURES FOR THE PERIOD WILL START OUT 10 DEGREES ABOVE NORMAL
MONDAY THEN COOL TO NEAR NORMAL TUESDAY THROUGH FRIDAY AS A COLD
FRONT MOVES THROUGH THE AREA SOMETIME ON TUESDAY.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 529 PM MDT FRI MAY 31 2013
VFR CONDITIONS WILL PREVAIL AT BOTH TAF SITES. WINDS WILL DECREASE
SHORTLY AFTER TAF ISSUANCE AS MIXING LESSENS. LATER TONIGHT A COLD
FRONT WILL PASS BOTH TAF SITES AND WINDS WILL INCREASE BEHIND THE
FRONT. SCATTERED TO BROKEN CEILING AROUND 10 KFT ARE EXPECTED
LATER TONIGHT WITH A LOWER BROKEN DECK AROUND 5 KFT DEVELOPING
TOMORROW MORNING. WINDS WILL INCREASE THROUGH THE MORNING HOURS
AND GUSTS OF OVER 30 KNOTS ARE EXPECTED THROUGH THE AFTERNOON.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...RED FLAG WARNING UNTIL 8 PM MDT THIS EVENING FOR KSZ013-027.
CO...RED FLAG WARNING UNTIL 8 PM MDT THIS EVENING FOR COZ252>254.
NE...NONE.
&&
$$
SHORT TERM...DR
LONG TERM...JTL
AVIATION...BRB
AREA FORECAST DISCUSSION
NWS TOPEKA KS
344 PM CDT THU MAY 30 2013
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 343 PM CDT THU MAY 30 2013
WATER VAPOR LOOP SHOWING CONVECTIVE SYSTEM OVER WESTERN MO MOVING
SLOWLY EWD AHEAD OF ONE MID-LEVEL TROUGH. HOWEVER...THERE IS A VERY
SHORT WAVELENGTH BETWEEN THAT TROUGH AND THE FOLLOWING IMPULSE THAT
APPEARS TO BE OVER WRN KS AT MID AFTERNOON. SCATTERED SHOWERS AND
THUNDERSTORMS HAVE FIRED OVER WRN KS AHEAD OF THIS FEATURE AND THEY
ARE MOVING EWD. SHORT RANGE MODEL GUIDANCE NOT RESOLVING THE
DETAILS OF THIS VERY WELL...HOWEVER THE 17Z HRRR DOES NOW HAVE A
LINE OF CONVECTION MOVING INTO CENTRAL KS BY 21Z. IT FORECASTS THIS
TO BREAK UP WITH THE REMNANTS MOVING ACROSS NORTHEAST KS DURING THE
EVENING...AND THEN ANOTHER SMALL CONVECTIVE SYSTEM MOVES SOUTHEAST
OUT OF NEBRASKA INTO NORTHEAST KS LATER TONIGHT. DO NOT HAVE HIGH
CONFIDENCE IN THIS SCENARIO...ALTHOUGH SOME TYPE OF SMALL MCS WOULD
APPEAR TO BE LIKELY IN CENTRAL/NORTHEAST KS LATER TONIGHT. THIS
POSSIBLE SYSTEM WOULD APPEAR TO MOVE THROUGH FAST ENOUGH AS TO NOT
CAUSE SIG PROBLEMS WITH HEAVY RAIN/FLOODING. EARLIER CONCERNS ABOUT
WARM AIR ADVECTION CAUSING LIFT AND THUNDERSTORM AREA WITH
POTENTIALLY HEAVY RAINFALL OVER EC KS TONIGHT ARE LESSENING AS
CONVECTIVE BOUNDARY SAGS WAY SOUTH INTO NORTHEAST OKLAHOMA.
THUS...HAVE CANCELLED FLASH FLOOD WATCH THAT WAS IN EFFECT FOR THIS
AFTERNOON...AND AM NOT PLANNING ON GOING OUT WITH A NEW ONE AT THIS
TIME. CONFIDENCE IN THE DETAILS OF PRECIPITATION EVOLUTION TONIGHT
IS NOT HIGH.
ON FRIDAY...FRONTAL BOUNDARY SHOULD MAKE IT FAR ENOUGH SOUTH BY
AFTERNOON THAT THE MAIN CHANCE OF THUNDERSTORM ACTIVITY WOULD BE IN
EC KS...MAINLY SOUTHEAST OF THE KANSAS TURNPIKE. LOWS TONIGHT
EXPECTED TO BE AROUND 60 OVER NC KS AND IN THE MID 60S EC. HIGHS ON
FRIDAY ARE FORECAST TO MAX OUT AROUND 80.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 343 PM CDT THU MAY 30 2013
DETAILS ONLY GET MURKIER FOR FRIDAY EVENING...BUT AT LEAST SOME
CHANCE SHOULD EXIST AHEAD OF THE SYNOPTIC BOUNDARY FOR SOUTHERN AND
EASTERN LOCATIONS. SUFFICIENT SHEAR AND INSTABILITY WOULD SUPPORT A
SEVERE CONCERN THROUGH THIS TIME AS WELL..BUT THE SOUTHEASTWARD
SHIFTING UPPER LOW SHOULD PUSH THE EFFECTIVE FRONT SOUTH OF THE AREA
BY DAWN. COLD AIR ADVECTION SETS IN FOR SATURDAY ON NORTHWEST
BREEZES WITH SOME STRATUS/STRATOCU DEVELOPING BY MID AFTERNOON.
WEAKENING WINDS AND CLEARING SKIES SPELL A COOL NIGHT SATURDAY
NIGHT. SURFACE RIDGE SETS UP FOR SUNDAY WITH LITTLE IF ANY
MODERATION TO HIGHS.
GULF MOISTURE DOES NOT GET COMPLETELY SCOURED OUT...AND BY LATE
MONDAY SOUTH WINDS AHEAD OF AN APPROACHING NORTHERN ROCKIES CYCLONE
WILL BRING THUNDERSTORM CHANCES BACK. BEST CHANCES LOOK TO BE
TUESDAY INTO TUESDAY NIGHT WITH GOOD MODEL AGREEMENT ON A MID LEVEL
WAVE PASSING. TEMPS SHOULD GENERALLY BE NEAR EARLY JUNE NORMALS SAVE
ANY DAYTIME MCS ACTIVITY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1239 PM CDT THU MAY 30 2013
CHALLENGING FORECAST. LINE OF SHOWERS SHOULD HAVE MOVED THROUGH
TOP AND FOE BY A LITTLE AFTER 18Z TODAY. THEN ANOTHER CHANCE OF
SHOWERS AND STORMS LATE AFTERNOON EARLY EVENING...AND ANOTHER
CHANCE LATE TONIGHT AND FRIDAY MORNING. OTHER THAN IN
SHOWERS...WINDS SHOULD BE FROM THE SOUTH. POTENTIAL MVFR
CONDITIONS IN SOME OF THE HEAVIER SHOWERS AND STORMS.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...60
LONG TERM...65
AVIATION...PHILLIPS
AREA FORECAST DISCUSSION
NWS PADUCAH KY
1016 PM CDT FRI MAY 31 2013
.MESOSCALE DISCUSSION...
ISSUED AT 1016 PM CDT FRI MAY 31 2013
NOT MUCH TO ADD TO THE UPDATE SECTION BELOW. THE 0-3KM BULK SHEAR
OF 25 TO 30 KTS ORIENTED FROM THE SOUTHWEST OR WEST SOUTHWEST
INDICATED BY THE RAP MODEL WILL HAVE A HARD TIME SUSTAINING A
SEVERE MCS THROUGH THE AREA OVERNIGHT. IN GENERAL THE BETTER SHEAR
WILL BE OVER SOUTHERN ILLINOIS AND SOUTHEAST MISSOURI...SO WOULD
EXPECT A BETTER PROBABILITY OF SEVERE WEATHER IN THOSE
AREAS...WITH A LESSER CHANCE FARTHER SOUTHEAST INTO SOUTHWEST
INDIANA AND WEST KENTUCKY. WITH WEST SOUTHWESTERLY LOW-LEVEL
SHEAR...ANY SEGMENT OF THE LINE OF STORMS THAT GETS ORIENTED FROM
NORTHWEST TO SOUTHEAST OR EVEN NORTH TO SOUTH WILL HAVE AN
ENHANCED CHANCE OF DAMAGING WINDS AND TORNADOES.
&&
.UPDATE...
ISSUED AT 705 PM CDT FRI MAY 31 2013
THE SCATTERED LIGHT SHOWERS OVER SOUTHEAST MISSOURI SHOULD
DISSIPATE THROUGH SUNSET.
THE LATEST HRRR MODEL PUSHES THE MCS FROM THE ST LOUIS METRO
EASTWARD ALONG THE I-64 CORRIDOR OF SOUTHERN ILLINOIS LATE THIS
EVENING INTO THE EARLY MORNING HOURS. THE SYSTEM MAY BE SEVERE AS
IT ENTERS THE NORTHWEST PORTION OF THE AREA...BUT THE HRRR DOES
INDICATE THAT IT WILL BE WEAKENING AS IT MOVES EASTWARD TOWARD THE
KEVV TRI STATE. THE MAIN SEVERE WEATHER CONCERN WILL BE DAMAGING
WINDS...WITH A FEW BRIEF TORNADOES POSSIBLE AS WELL.
AS IT MOVES EAST...IT WILL BE SAGGING SLOWLY SOUTHWARD ACROSS THE
REMAINDER OF THE AREA...REACHING THE KPAH AREA AROUND 3 AM. THIS
SOUTHWARD MOVING PORTION OF THE MCS SHOULD NOT BE SEVERE. THE
TIMING OF THE HRRR MAY BE OFF A FEW HOURS...BUT THE OVERALL
EVOLUTION SEEMS VERY REASONABLE GIVEN THE LATEST OBSERVATIONS.
OF COURSE...LOCALLY HEAVY RAINFALL WILL BE A CONCERN...ESPECIALLY
WITH THE STRONGER PORTION OF THE SYSTEM...I-64 AREA. AT THIS
TIME...FEEL THAT IT WILL BE MOVING QUICKLY ENOUGH AND THAT THE
STRONGER HEAVIER CORES WILL BE LIMITED IN SPACE...SO WILL NOT BE
ISSUING A FLOOD/FLASH FLOOD WATCH AT THIS TIME.
THE AVIATION SECTION HAS BEEN UPDATED FOR THE 00Z TAF ISSUANCE.
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY NIGHT)
ISSUED AT 135 PM CDT FRI MAY 31 2013
ALL EYES ON THE NEAR TERM AS WE REMAIN IN WARM/MOIST/UNSTABLE
S-SWLY FLOW...AWAITING ARRIVAL OF LOW PRESSURE STORM SYSTEM AND
ASSOCIATED FRONT.
VERY NEAR TERM ENVIRON IS WORKED OVER. SOME BREAKS IN CLOUDS THIS
PM COULD DESTABILIZE AND ALLOW FOR POP UP STUFF...BUT MAIN THREAT
AREAS LOOK TO BE WEST AND EAST OF OURS.
TONIGHT...ALL CONDITIONS ARE PRIMED FOR CONVECTION/MCS TO FORM TO
OUR WEST...PROBABLY FORMING/MIGRATING INTO SRN MO/NRN AR AREA BY
MIDNIGHT...THEN PROPAGATING EASTWARD INTO OUR AREA OVERNIGHT. IT
SHOULD BE NOT ALTOGETHER DIFFERENT FROM THIS MORNING`S
ROUND...WHERE IT MOVES IN AND PRODUCES ABOUT IN INCH QPF ON
AVERAGE (WEST OF MS RIVER) AND WANES THE FURTHER EAST IT TRAVELS.
THE ATMOS SHOULD REST TMRW MORNING IN ITS WAKE...THEN RECHARGE
TMRW PM AS THE UPPER LOW/HEIGHT FALLS MOVE IN AND THUS...DRIVE THE
FRONT INTO THE REGION. THE PM/EVENING HOURS STILL LOOK LIKE THE
BEST CHANCE TIME FOR STRONG/SVR STORMS...AND ANOTHER INCH OR SO
(AVERAGE) QPF IS FORECAST. THIS PUTS STORM TOTALS AT ABOUT 2
INCHES...AND GUIDANCE SUGGESTS 3 INCHES OR MORE IS NECESSARY FOR A
WATCH. THEREFORE WE ARE INCLINED TO LAY OFF THAT HEADLINE FOR NOW
AND JUST HEIGHTEN AWARENESS ON THE HWO/PRODUCTS. COLLAB COULD
CHANGE THIS BUT GENERALLY/WATCHES POSTED TO OUR PERIPHERY ARE WHERE
HIGHER QPF EXISTS ANYWAY. IF WE END UP DOING ONE/WE`LL PROB RUN
THRU THE WHOLE EVENT FOR THE WHOLE AREA...STAY TUNED.
FASTER TIMING TO SYSTEM PASSAGE/FROPA NOW HAS 12Z MODELING OF PCPN
ENDING BY SAT NIGHT MIDNIGHT WITH DRY/COOLER AIR WORKING IN FOR
SUNDAY INTO EARLY NEXT WEEK. THIS HAS BEEN A DAILY TREND AND ONE
WE`RE COMFORTABLE FOLLOWING.
.LONG TERM...(MONDAY THROUGH FRIDAY)
ISSUED AT 239 PM CDT FRI MAY 31 2013
THE MED RANGE MODELS ARE IN REASONABLE AGREEMENT THROUGH AT LEAST
DAY 5 WITH THE NEXT LONGWAVE EXPECTED TO AFFECT THE NORTH CENTRAL
PART OF THE CONUS. MEANWHILE...MONDAY THROUGH TUE NIGHT...THE PAH
FORECAST AREA WILL BE MOSTLY CLEAR AND DRY UNDER NWRLY TO WRLY
FLOW ALOFT AND A SFC RIDGE. THE GFS AND ITS ENSEMBLE MEAN APPEARED
TO DEPICT THE MID LEVEL LONGWAVE AS SHALLOWER THAN THE ECWMF AND
ITS ENSEMBLE MEAN. THE GEM WAS PRETTY DYNAMIC TOO...AND HAD PCPN
STARTING IN OUR WEST AFTER SUNRISE WED. THE MODEL BLEND PROVIDED
VERY LIMITED POPS THROUGH WED NIGHT AS THE MODELS DO NOT AGREE
EXACTLY ON THE DETAILS OF HOW MUCH LIFT MAY OCCUR IN THE
INCREASINGLY MOIST AIR MASS.
ON THU...AS THE ATMOSPHERE DESTABILIZES IN THE HEAT OF THE DAY...MID
LEVEL SHRTWV ENERGY SHOULD BE ABLE TO ACT ON THE MOISTURE ENOUGH TO
GENERATE SCATTERED SHOWERS AND TSTMS AS THE AXIS OF THE MAIN WAVE
DRAWS NEAR. A LOW LEVEL TROF/CONVERGENCE ZONE...SHOWN MORE
PROMINENTLY BY THE 12Z GFS THAN THE 12Z ECMWF...SHOULD SET UP
ACROSS THE MIDWEST BY THEN...HELPING TO FOCUS CONVECTION SOMEWHAT
BETTER. BY EARLY FRI /DAY 7/...A CONVERGENCE ZONE/SFC WIND SHIFT
IS FORECAST TO BE SOMEWHERE IN OUR VICINITY...INCREASING CHANCES
OF GETTING WET TO ABOUT ONE OUT OF TWO. THE BEST QPF SEEMS MOST
LIKELY THEN.
EXPECT TEMPS TO START OUT ON THE COOL SIDE AND TO SLOWLY WARM
THROUGH FRI TO CLOSER TO CLIMATOLOGICAL NORMALS.
&&
.AVIATION...
ISSUED AT 705 PM CDT FRI MAY 31 2013
SHOULD SEE PERIODIC MID-LEVEL CEILINGS THROUGH THE EVENING AHEAD
OF THE MCS MOVING EAST/SOUTHEAST TOWARD THE AREA. LOOKS LIKE THE
SYSTEM WILL BE WEAKENING AS IT REACHES KEVV AND KCGI JUST AFTER
06Z. KEVV WOULD HAVE SOME POTENTIAL FOR HEFTY WESTERLY GUSTS AS
THE SYSTEM ARRIVES...BUT THEY SHOULD BE MUCH WEAKER AND MORE
NORTHERLY AT KCGI. HAVE INSERTED MVFR CONDITIONS WITH THUNDER IN A
4 HOUR TEMPO GROUP AT EACH SITE.
ONCE THE MAIN LINE MOVES THROUGH A SITE...A 2 TO 4 HOUR PERIOD OF
RAIN/SHOWERS AND POSSIBLY A FEW STRAY LIGHTNING STRIKES CAN BE
EXPECTED. THE AREA SHOULD BE DRYING OUT THROUGH THE LATE MORNING
AND AFTERNOON HOURS...AND GUSTY SOUTH SOUTHWEST WINDS ARE LIKELY
THROUGH THE DAY.
WOULD BE SURPRISED TO SEE CONVECTIVE DEVELOPMENT NEAR THE TAF
SITES BEFORE THE END OF THIS 00Z PERIOD. THE COLD FRONT WILL MOVE
THROUGH BEYOND THIS PERIOD...AND THERE MAY BE ANOTHER ROUND OF
THUNDERSTORMS ALONG IT.
&&
.PAH WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
MO...NONE.
IN...NONE.
KY...NONE.
&&
$$
MESOSCALE...DRS
UPDATE...DRS
SHORT TERM...DH
LONG TERM...DB
AVIATION...DRS
AREA FORECAST DISCUSSION
NWS JACKSON KY
939 PM EDT FRI MAY 31 2013
.UPDATE...
ISSUED AT 938 PM EDT FRI MAY 31 2013
REMOVED POPS ACROSS MUCH OF THE REGION...WITH ONLY A SLIGHT CHANCE IN
THE FAR NORTHERN SECTIONS OVER THE NEXT COUPLE OF HOURS. BOTH JKL AND
NEIGHBORING OFFICES ARE SHOWING DRY CONDITIONS...WITH LITTLE IN THE
WAY OF EXPECTED REDEVELOPMENT DURING THE REMAINDER OF THE NIGHT. ALL
OTHER WEATHER VARIABLES SEEM TO BE ON TRACK...SO OPTED TO KEEP WITH
PREVIOUS FORECAST.
UPDATE ISSUED AT 600 PM EDT FRI MAY 31 2013
BASED ON CURRENT RADAR WENT AHEAD AND INCREASED POPS FOR NORTHWESTERN
COUNTIES IN THE AREA...WITH THE POTENTIAL FOR SOME SCATTERED SHOWERS
OVER THE NEXT HOUR OR TWO ALONG THE FAR SOUTHWESTERN COUNTIES AS
WELL. THAT BEING SAID...LOOKING AT MODEL PARAMETERS...DYNAMICS SEEM TO BE
FAIRLY WEAK OVER MUCH OF EASTERN KY...AND HI RES MODEL /HRRR/ PRECIP
SHOWS A QUICK DIMINISHING TREND THROUGHOUT THE EVENING. TRIED TO
REFLECT THIS IDEA WITHIN THE POPS AND WX...WITH THE BEST CHANCE FOR
CONVECTION REMAINING OVER THE NORTHERN COUNTIES THROUGH THE EVENING.
BUT WITH VERY LITTLE LIGHTNING SHOWING UP ON RADAR AND WEAK
INSTABILITY IN OUR AREA...ONLY SLIGHT CHANCE OF THUNDER WAS
WARRANTED.
&&
.SHORT TERM...(THIS EVENING THROUGH SATURDAY NIGHT)
ISSUED AT 320 PM EDT FRI MAY 31 2013
MESOSCALE CONVECTIVE VORTEX WHICH HAD BEEN NEAR MADISONVILLE KY AT
1230 PM HAS PULLED NORTHEAST AND IS NOW NEAR LOUISVILLE. STRONGEST
CONVECTION HAS BEEN OCCURRING AHEAD OF THIS FEATURE AND NOW PULLING
INTO SOUTHWEST OH. CONVECTION TRAILS SOUTH TO WEST OF LAKE CUMBERLAND
ALONG OLD OUTFLOW BOUNDARY. WITH THE MOVEMENT OF THIS CONVECTION NNE
IT HAS ONLY BEEN VERY SLOWLY NEARING THE SW PART OF FORECAST AREA.
HOWEVER...OUTFLOW FROM THIS COULD STILL SERVE AS TRIGGER FOR
CONVECTION OVER THE FAR WEST PART OF FORECAST AREA. THE HRRR HAS BEEN
PERSISTENT IN TRYING TO BRING CONVECTION INTO OUR AREA...WITH THE 17Z
RUN TRYING TO MOVE CONVECTION INTO THE AREA AFTER 22Z...AND THEN SLOWLY
DISSIPATING AS IT MOVES EAST. WITH THE MCV MOVING AWAY AND WITH LOSS
OF DAYTIME HEATING DO EXPECT ANY CONVECTION IN OUR AREA TO DECREASE
QUICKLY THIS EVENING AND WILL DROP SHOWERS AND THUNDERSTORMS FROM
FORECAST AFTER MIDNIGHT.
A SHORT WAVE MOVING OUT OF THE SOUTHERN PLAINS SHOULD TRIGGER MORE
CONVECTION OVER MO TONIGHT...WITH THE EFFECTS OF THIS REMAINING TO
OUR WEST OVERNIGHT INTO SATURDAY MORNING. SATURDAY WILL BRING A
CHANCE FOR MORE SHOWERS AND THUNDERSTORMS WITH ANY OUTFLOW
BOUNDARIES FROM OVERNIGHT CONVECTION TO OUR WEST POSSIBLY SERVING AS
TRIGGER FOR MAINLY AFTERNOON SHOWERS AND THUNDERSTORMS ON SATURDAY.
IT IS STILL POSSIBLE SOME OF THE STORMS SATURDAY AFTERNOON AND
EVENING COULD BECOME SEVERE...WITH GREATER INSTABILITY DURING THE
AFTERNOON INTO THE EVENING.
MODELS HAVE TRENDED TOWARDS A QUICKER SOLUTION WITH CONVECTION AHEAD
OF THE COLD FRONT MOVING INTO THE AREA SATURDAY NIGHT. WE HAVE
FOLLOWED THIS IDEA WITH LIKELY SHOWER AND THUNDERSTORM PROBABILITIES
AREA WIDE FOR SATURDAY NIGHT.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 320 PM EDT FRI MAY 31 2013
A COLD FRONT SHOULD BE ABOUT READY TO ENTER THE FORECAST AREA FROM
THE NW AT THE START OF THE PERIOD...WITH SUPPORT FROM AN APPROACHING
UPPER TROUGH...AND A RIBBON OF HIGHER DEW POINTS OFF THE GULF ALONG
THE FRONT BEING ADVECTED ALONG BY A 30-40 KT LOW LEVEL FLOW JUST OFF
THE SURFACE. ALL THIS CONSIDERED...THERE WILL LIKELY BE AN ONGOING
CONVECTIVE EVENT...WITH MODELS SHOWING THE GREATEST LIKELIHOOD OF
THIS IN THE SE PART OF THE AREA. AS THE FRONT SLOWLY PUSHES INTO AND
THROUGH THE FORECAST AREA SUNDAY AND SUNDAY EVENING...THERE COULD
ALSO BE ADDITIONAL DEVELOPMENT...WITH THE GREATEST OPPORTUNITY FOR
THIS IN THE SE WHERE FROPA WILL OCCUR LAST. THE LAST OF ANY
LINGERING PRECIP SHOULD END SUNDAY NIGHT OR EARLY MONDAY AS THE
FRONT CONTINUES ON TO OUR SE.
HIGH PRESSURE OVER THE MIDWEST WILL SUPPLY NOTICEABLY DRIER AND
SOMEWHAT COOLER AIR EARLY IN THE WEEK UNDER WNW FLOW ALOFT. RIDGING
ALOFT WILL PASS OVER ON TUESDAY INTO WEDNESDAY...WITH THE SURFACE
HIGH SHIFTING EASTWARD. THIS WILL BRING A CONTINUATION OF DRY
WEATHER...BUT WITH WARMING ALREADY OCCURRING AND AN EVENTUAL
INCREASE IN SURFACE MOISTURE.
AFTER THIS...MODEL DIFFERENCES BETWEEN THE GFS AND ECMWF BECOME MORE
APPARENT LATE IN THE WEEK. THE ECMWF DEVELOPS AN UPPER RIDGE OVER
THE CAROLINAS...BUT THIS FEATURE IS LACKING IN THE OPERATIONAL GFS.
ALL MODELS INDICATE AN UPPER LOW HEADING EAST ALONG THE CANADIAN
BORDER AND INTO ONTARIO...WITH A SOUTHWARD EXTENDING TROUGH. THE 00Z
ECMWF DOES NOT ALLOW AS MUCH OF A SOUTHERN EXTENSION OF THIS TROUGH
DUE TO ITS CAROLINA RIDGE. THE RESULT IS THAT THE GFS DEVELOPS
CONVECTION OVER THE LOCAL AREA FROM WEDNESDAY ON. MEANWHILE...THE
ECMWF SHOWS LIGHT PRECIP ONLY ON THURSDAY AS THE TROUGH SCOOTS BY TO
OUR NORTH. THE GEM AND GFS ENSEMBLE MEAN SUPPORT THE OPERATIONAL
GFS...AND PREFER TO WEIGHT THE FORECAST TOWARD IT...WITH JUST A BIT
OF ECMWF INFLUENCE TO KNOCK THE POPS DOWN SLIGHTLY FROM WHERE THEY
WOULD OTHERWISE BE.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 800 PM EDT FRI MAY 31 2013
AFTER CONVECTION MOVED THROUGH PORTIONS OF THE WESTERN AND NORTHERN
SECTIONS OF THE REGION THIS AFTERNOON...CONDITIONS ARE CONTINUING TO
IMPROVE...WITH CLOUD COVER SLOWLY DIMINISHING ACROSS THE AREA. AS A
RESULT...EXPECT SCT CIGS THROUGH THE EVENING WITH VFR CONDITIONS AND
LIGHT WINDS. A COLD FRONT AND ANOTHER AREA OF MOISTURE WILL MOVE
INTO THE REGION DURING THE DAY TOMORROW...WITH POTENTIAL SHOWERS AND
THUNDERSTORMS POISED TO REACH THE NORTHERN SECTIONS AROUND NOON...AND
TAF SITES TOWARD THE END OF THE TAF PERIOD. SINCE CONVECTION HAS NOT
YET DEVELOPED...THERE IS STILL SOME UNCERTAINTY OF EXACT TIMING AND
SET UP AT TAF SITES. AS A RESULT...JUST WENT WITH VCTS AT THIS TIME
WITH TRENDING LOWERING CLOUDS. CHANGES ON EXACT CIG HEIGHTS AND
WEATHER IMPACTS WILL BE UPDATED AS WE NEAR CLOSER TO THE EVENT.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...JMW
SHORT TERM...SBH
LONG TERM...HAL
AVIATION...JMW
AREA FORECAST DISCUSSION
NWS PADUCAH KY
706 PM CDT FRI MAY 31 2013
.UPDATE...
ISSUED AT 705 PM CDT FRI MAY 31 2013
THE SCATTERED LIGHT SHOWERS OVER SOUTHEAST MISSOURI SHOULD
DISSIPATE THROUGH SUNSET.
THE LATEST HRRR MODEL PUSHES THE MCS FROM THE ST LOUIS METRO
EASTWARD ALONG THE I-64 CORRIDOR OF SOUTHERN ILLINOIS LATE THIS
EVENING INTO THE EARLY MORNING HOURS. THE SYSTEM MAY BE SEVERE AS
IT ENTERS THE NORTHWEST PORTION OF THE AREA...BUT THE HRRR DOES
INDICATE THAT IT WILL BE WEAKENING AS IT MOVES EASTWARD TOWARD THE
KEVV TRI STATE. THE MAIN SEVERE WEATHER CONCERN WILL BE DAMAGING
WINDS...WITH A FEW BRIEF TORNADOES POSSIBLE AS WELL.
AS IT MOVES EAST...IT WILL BE SAGGING SLOWLY SOUTHWARD ACROSS THE
REMAINDER OF THE AREA...REACHING THE KPAH AREA AROUND 3 AM. THIS
SOUTHWARD MOVING PORTION OF THE MCS SHOULD NOT BE SEVERE. THE
TIMING OF THE HRRR MAY BE OFF A FEW HOURS...BUT THE OVERALL
EVOLUTION SEEMS VERY REASONABLE GIVEN THE LATEST OBSERVATIONS.
OF COURSE...LOCALLY HEAVY RAINFALL WILL BE A CONCERN...ESPECIALLY
WITH THE STRONGER PORTION OF THE SYSTEM...I-64 AREA. AT THIS
TIME...FEEL THAT IT WILL BE MOVING QUICKLY ENOUGH AND THAT THE
STRONGER HEAVIER CORES WILL BE LIMITED IN SPACE...SO WILL NOT BE
ISSUING A FLOOD/FLASH FLOOD WATCH AT THIS TIME.
THE AVIATION SECTION HAS BEEN UPDATED FOR THE 00Z TAF ISSUANCE.
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY NIGHT)
ISSUED AT 135 PM CDT FRI MAY 31 2013
ALL EYES ON THE NEAR TERM AS WE REMAIN IN WARM/MOIST/UNSTABLE
S-SWLY FLOW...AWAITING ARRIVAL OF LOW PRESSURE STORM SYSTEM AND
ASSOCIATED FRONT.
VERY NEAR TERM ENVIRON IS WORKED OVER. SOME BREAKS IN CLOUDS THIS
PM COULD DESTABILIZE AND ALLOW FOR POP UP STUFF...BUT MAIN THREAT
AREAS LOOK TO BE WEST AND EAST OF OURS.
TONIGHT...ALL CONDITIONS ARE PRIMED FOR CONVECTION/MCS TO FORM TO
OUR WEST...PROBABLY FORMING/MIGRATING INTO SRN MO/NRN AR AREA BY
MIDNIGHT...THEN PROPAGATING EASTWARD INTO OUR AREA OVERNIGHT. IT
SHOULD BE NOT ALTOGETHER DIFFERENT FROM THIS MORNING`S
ROUND...WHERE IT MOVES IN AND PRODUCES ABOUT IN INCH QPF ON
AVERAGE (WEST OF MS RIVER) AND WANES THE FURTHER EAST IT TRAVELS.
THE ATMOS SHOULD REST TMRW MORNING IN ITS WAKE...THEN RECHARGE
TMRW PM AS THE UPPER LOW/HEIGHT FALLS MOVE IN AND THUS...DRIVE THE
FRONT INTO THE REGION. THE PM/EVENING HOURS STILL LOOK LIKE THE
BEST CHANCE TIME FOR STRONG/SVR STORMS...AND ANOTHER INCH OR SO
(AVERAGE) QPF IS FORECAST. THIS PUTS STORM TOTALS AT ABOUT 2
INCHES...AND GUIDANCE SUGGESTS 3 INCHES OR MORE IS NECESSARY FOR A
WATCH. THEREFORE WE ARE INCLINED TO LAY OFF THAT HEADLINE FOR NOW
AND JUST HEIGHTEN AWARENESS ON THE HWO/PRODUCTS. COLLAB COULD
CHANGE THIS BUT GENERALLY/WATCHES POSTED TO OUR PERIPHERY ARE WHERE
HIGHER QPF EXISTS ANYWAY. IF WE END UP DOING ONE/WE`LL PROB RUN
THRU THE WHOLE EVENT FOR THE WHOLE AREA...STAY TUNED.
FASTER TIMING TO SYSTEM PASSAGE/FROPA NOW HAS 12Z MODELING OF PCPN
ENDING BY SAT NIGHT MIDNIGHT WITH DRY/COOLER AIR WORKING IN FOR
SUNDAY INTO EARLY NEXT WEEK. THIS HAS BEEN A DAILY TREND AND ONE
WE`RE COMFORTABLE FOLLOWING.
.LONG TERM...(MONDAY THROUGH FRIDAY)
ISSUED AT 239 PM CDT FRI MAY 31 2013
THE MED RANGE MODELS ARE IN REASONABLE AGREEMENT THROUGH AT LEAST
DAY 5 WITH THE NEXT LONGWAVE EXPECTED TO AFFECT THE NORTH CENTRAL
PART OF THE CONUS. MEANWHILE...MONDAY THROUGH TUE NIGHT...THE PAH
FORECAST AREA WILL BE MOSTLY CLEAR AND DRY UNDER NWRLY TO WRLY
FLOW ALOFT AND A SFC RIDGE. THE GFS AND ITS ENSEMBLE MEAN APPEARED
TO DEPICT THE MID LEVEL LONGWAVE AS SHALLOWER THAN THE ECWMF AND
ITS ENSEMBLE MEAN. THE GEM WAS PRETTY DYNAMIC TOO...AND HAD PCPN
STARTING IN OUR WEST AFTER SUNRISE WED. THE MODEL BLEND PROVIDED
VERY LIMITED POPS THROUGH WED NIGHT AS THE MODELS DO NOT AGREE
EXACTLY ON THE DETAILS OF HOW MUCH LIFT MAY OCCUR IN THE
INCREASINGLY MOIST AIR MASS.
ON THU...AS THE ATMOSPHERE DESTABILIZES IN THE HEAT OF THE DAY...MID
LEVEL SHRTWV ENERGY SHOULD BE ABLE TO ACT ON THE MOISTURE ENOUGH TO
GENERATE SCATTERED SHOWERS AND TSTMS AS THE AXIS OF THE MAIN WAVE
DRAWS NEAR. A LOW LEVEL TROF/CONVERGENCE ZONE...SHOWN MORE
PROMINENTLY BY THE 12Z GFS THAN THE 12Z ECMWF...SHOULD SET UP
ACROSS THE MIDWEST BY THEN...HELPING TO FOCUS CONVECTION SOMEWHAT
BETTER. BY EARLY FRI /DAY 7/...A CONVERGENCE ZONE/SFC WIND SHIFT
IS FORECAST TO BE SOMEWHERE IN OUR VICINITY...INCREASING CHANCES
OF GETTING WET TO ABOUT ONE OUT OF TWO. THE BEST QPF SEEMS MOST
LIKELY THEN.
EXPECT TEMPS TO START OUT ON THE COOL SIDE AND TO SLOWLY WARM
THROUGH FRI TO CLOSER TO CLIMATOLOGICAL NORMALS.
&&
.AVIATION...
ISSUED AT 705 PM CDT FRI MAY 31 2013
SHOULD SEE PERIODIC MID-LEVEL CEILINGS THROUGH THE EVENING AHEAD
OF THE MCS MOVING EAST/SOUTHEAST TOWARD THE AREA. LOOKS LIKE THE
SYSTEM WILL BE WEAKENING AS IT REACHES KEVV AND KCGI JUST AFTER
06Z. KEVV WOULD HAVE SOME POTENTIAL FOR HEFTY WESTERLY GUSTS AS
THE SYSTEM ARRIVES...BUT THEY SHOULD BE MUCH WEAKER AND MORE
NORTHERLY AT KCGI. HAVE INSERTED MVFR CONDITIONS WITH THUNDER IN A
4 HOUR TEMPO GROUP AT EACH SITE.
ONCE THE MAIN LINE MOVES THROUGH A SITE...A 2 TO 4 HOUR PERIOD OF
RAIN/SHOWERS AND POSSIBLY A FEW STRAY LIGHTNING STRIKES CAN BE
EXPECTED. THE AREA SHOULD BE DRYING OUT THROUGH THE LATE MORNING
AND AFTERNOON HOURS...AND GUSTY SOUTH SOUTHWEST WINDS ARE LIKELY
THROUGH THE DAY.
WOULD BE SURPRISED TO SEE CONVECTIVE DEVELOPMENT NEAR THE TAF
SITES BEFORE THE END OF THIS 00Z PERIOD. THE COLD FRONT WILL MOVE
THROUGH BEYOND THIS PERIOD...AND THERE MAY BE ANOTHER ROUND OF
THUNDERSTORMS ALONG IT.
&&
.PAH WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
MO...NONE.
IN...NONE.
KY...NONE.
&&
$$
UPDATE...DRS
SHORT TERM...DH
LONG TERM...DB
AVIATION...DRS
AREA FORECAST DISCUSSION
NWS JACKSON KY
800 PM EDT FRI MAY 31 2013
.UPDATE...
ISSUED AT 600 PM EDT FRI MAY 31 2013
BASED ON CURRENT RADAR WENT AHEAD AND INCREASED POPS FOR NORTHWESTERN
COUNTIES IN THE AERA...WITH THE POTENTIAL FOR SOME SCATTERED SHOWERS
OVER THE NEXT HOUR OR TWO ALONG THE FAR SOUTHWESTERN COUNTIES AS
WELL. THAT BEING SAID...LOOKING AT MODEL PARAMETERS...DYNAMICS SEEM TO BE
FAIRLY WEAK OVER MUCH OF EASTERN KY...AND HI RES MODEL /HRRR/ PRECIP
SHOWS A QUICK DIMINISHING TREND THROUGHOUT THE EVENING. TRIED TO
REFLECT THIS IDEA WITHIN THE POPS AND WX...WITH THE BEST CHANCE FOR
CONVECTION REMAINING OVER THE NORTHERN COUNTIES THROUGH THE EVENING.
BUT WITH VERY LITTLE LIGHTNING SHOWING UP ON RADAR AND WEAK
INSTABILITY IN OUR AREA...ONLY SLIGHT CHANCE OF THUNDER WAS
WARRANTED.
&&
.SHORT TERM...(THIS EVENING THROUGH SATURDAY NIGHT)
ISSUED AT 320 PM EDT FRI MAY 31 2013
MESOSCALE CONVECTIVE VORTEX WHICH HAD BEEN NEAR MADISONVILLE KY AT
1230 PM HAS PULLED NORTHEAST AND IS NOW NEAR LOUISVILLE. STRONGEST
CONVECTION HAS BEEN OCCURRING AHEAD OF THIS FEATURE AND NOW PULLING
INTO SOUTHWEST OH. CONVECTION TRAILS SOUTH TO WEST OF LAKE CUMBERLAND
ALONG OLD OUTFLOW BOUNDARY. WITH THE MOVEMENT OF THIS CONVECTION NNE
IT HAS ONLY BEEN VERY SLOWLY NEARING THE SW PART OF FORECAST AREA.
HOWEVER...OUTFLOW FROM THIS COULD STILL SERVE AS TRIGGER FOR
CONVECTION OVER THE FAR WEST PART OF FORECAST AREA. THE HRRR HAS BEEN
PERSISTENT IN TRYING TO BRING CONVECTION INTO OUR AREA...WITH THE 17Z
RUN TRYING TO MOVE CONVECTION INTO THE AREA AFTER 22Z...AND THEN SLOWLY
DISSIPATING AS IT MOVES EAST. WITH THE MCV MOVING AWAY AND WITH LOSS
OF DAYTIME HEATING DO EXPECT ANY CONVECTION IN OUR AREA TO DECREASE
QUICKLY THIS EVENING AND WILL DROP SHOWERS AND THUNDERSTORMS FROM
FORECAST AFTER MIDNIGHT.
A SHORT WAVE MOVING OUT OF THE SOUTHERN PLAINS SHOULD TRIGGER MORE
CONVECTION OVER MO TONIGHT...WITH THE EFFECTS OF THIS REMAINING TO
OUR WEST OVERNIGHT INTO SATURDAY MORNING. SATURDAY WILL BRING A
CHANCE FOR MORE SHOWERS AND THUNDERSTORMS WITH ANY OUTFLOW
BOUNDARIES FROM OVERNIGHT CONVECTION TO OUR WEST POSSIBLY SERVING AS
TRIGGER FOR MAINLY AFTERNOON SHOWERS AND THUNDERSTORMS ON SATURDAY.
IT IS STILL POSSIBLE SOME OF THE STORMS SATURDAY AFTERNOON AND
EVENING COULD BECOME SEVERE...WITH GREATER INSTABILITY DURING THE
AFTERNOON INTO THE EVENING.
MODELS HAVE TRENDED TOWARDS A QUICKER SOLUTION WITH CONVECTION AHEAD
OF THE COLD FRONT MOVING INTO THE AREA SATURDAY NIGHT. WE HAVE
FOLLOWED THIS IDEA WITH LIKELY SHOWER AND THUNDERSTORM PROBABILITIES
AREA WIDE FOR SATURDAY NIGHT.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 320 PM EDT FRI MAY 31 2013
A COLD FRONT SHOULD BE ABOUT READY TO ENTER THE FORECAST AREA FROM
THE NW AT THE START OF THE PERIOD...WITH SUPPORT FROM AN APPROACHING
UPPER TROUGH...AND A RIBBON OF HIGHER DEW POINTS OFF THE GULF ALONG
THE FRONT BEING ADVECTED ALONG BY A 30-40 KT LOW LEVEL FLOW JUST OFF
THE SURFACE. ALL THIS CONSIDERED...THERE WILL LIKELY BE AN ONGOING
CONVECTIVE EVENT...WITH MODELS SHOWING THE GREATEST LIKELIHOOD OF
THIS IN THE SE PART OF THE AREA. AS THE FRONT SLOWLY PUSHES INTO AND
THROUGH THE FORECAST AREA SUNDAY AND SUNDAY EVENING...THERE COULD
ALSO BE ADDITIONAL DEVELOPMENT...WITH THE GREATEST OPPORTUNITY FOR
THIS IN THE SE WHERE FROPA WILL OCCUR LAST. THE LAST OF ANY
LINGERING PRECIP SHOULD END SUNDAY NIGHT OR EARLY MONDAY AS THE
FRONT CONTINUES ON TO OUR SE.
HIGH PRESSURE OVER THE MIDWEST WILL SUPPLY NOTICEABLY DRIER AND
SOMEWHAT COOLER AIR EARLY IN THE WEEK UNDER WNW FLOW ALOFT. RIDGING
ALOFT WILL PASS OVER ON TUESDAY INTO WEDNESDAY...WITH THE SURFACE
HIGH SHIFTING EASTWARD. THIS WILL BRING A CONTINUATION OF DRY
WEATHER...BUT WITH WARMING ALREADY OCCURRING AND AN EVENTUAL
INCREASE IN SURFACE MOISTURE.
AFTER THIS...MODEL DIFFERENCES BETWEEN THE GFS AND ECMWF BECOME MORE
APPARENT LATE IN THE WEEK. THE ECMWF DEVELOPS AN UPPER RIDGE OVER
THE CAROLINAS...BUT THIS FEATURE IS LACKING IN THE OPERATIONAL GFS.
ALL MODELS INDICATE AN UPPER LOW HEADING EAST ALONG THE CANADIAN
BORDER AND INTO ONTARIO...WITH A SOUTHWARD EXTENDING TROUGH. THE 00Z
ECMWF DOES NOT ALLOW AS MUCH OF A SOUTHERN EXTENSION OF THIS TROUGH
DUE TO ITS CAROLINA RIDGE. THE RESULT IS THAT THE GFS DEVELOPS
CONVECTION OVER THE LOCAL AREA FROM WEDNESDAY ON. MEANWHILE...THE
ECMWF SHOWS LIGHT PRECIP ONLY ON THURSDAY AS THE TROUGH SCOOTS BY TO
OUR NORTH. THE GEM AND GFS ENSEMBLE MEAN SUPPORT THE OPERATIONAL
GFS...AND PREFER TO WEIGHT THE FORECAST TOWARD IT...WITH JUST A BIT
OF ECMWF INFLUENCE TO KNOCK THE POPS DOWN SLIGHTLY FROM WHERE THEY
WOULD OTHERWISE BE.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 800 PM EDT FRI MAY 31 2013
AFTER CONVECTION MOVED THROUGH PORTIONS OF THE WESTERN AND NORTHERN
SECTIONS OF THE REGION THIS AFTERNOON...CONDITIONS ARE CONTINUING TO
IMPROVE...WITH CLOUD COVER SLOWLY DIMINISHING ACROSS THE AREA. AS A
RESULT...EXPECT SCT CIGS THROUGH THE EVENING WITH VFR CONDITIONS AND
LIGHT WINDS. A COLD FRONT AND ANOTHER AREA OF MOISTURE WILL MOVE
INTO THE REGION DURING THE DAY TOMORROW...WITH POTENTIAL SHOWERS AND
THUNDERSTORMS POISED TO REACH THE NORTHERN SECTIONS AROUND NOON...AND
TAF SITES TOWARD THE END OF THE TAF PERIOD. SINCE CONVECTION HAS NOT
YET DEVELOPED...THERE IS STILL SOME UNCERTAINTY OF EXACT TIMING AND
SET UP AT TAF SITES. AS A RESULT...JUST WENT WITH VCTS AT THIS TIME
WITH TRENDING LOWERING CLOUDS. CHANGES ON EXACT CIG HEIGHTS AND
WEATHER IMPACTS WILL BE UPDATED AS WE NEAR CLOSER TO THE EVENT.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...JMW
SHORT TERM...SBH
LONG TERM...HAL
AVIATION...JMW
AREA FORECAST DISCUSSION
NWS JACKSON KY
128 PM EDT THU MAY 30 2013
.UPDATE...
ISSUED AT 127 PM EDT THU MAY 30 2013
WILL UPDATE NDFD HOURLY DATA AND WEB SERVERS BY 135 PM FOR LATEST
OBSERVATIONAL TRENDS.
UPDATE ISSUED AT 1037 AM EDT THU MAY 30 2013
NDFD AND WEB SERVERS HAVE BEEN UPDATED FOR LATEST SATELLITE AND
SURFACE OBSERVATIONAL TRENDS. ZFP UPDATE NOT NEEDED AT THIS TIME. THE
12Z HRRR POINTS TOWARDS ISOLATED SHOWERS BEING POSSIBLE OVER THE FAR
WESTERN PART OF THE FORECAST AREA FOR A FEW HOURS THIS
AFTERNOON...SIMILAR TO YESTERDAY. EXPECT PROBABILITY TO REMAIN
BELOW 15 PERCENT AND WILL NOT ADD THIS TO FORECAST. THE 12Z NAM
SUPPORTS A DRY FORECAST THIS AFTERNOON....WITH LOW PROBABILITY OF
SHOWERS IN THE WESTERN PART OF THE AREA TONIGHT. THIS IS IN THE CURRENT
FORECAST FOR TONIGHT AND WILL LEAVE AS IS FOR NOW.
UPDATE ISSUED AT 750 AM EDT THU MAY 30 2013
UPDATED THE FORECAST MAINLY TO KEEP THE NEAR TERM GRIDS ON TRACK WITH
THE CURRENT OBS AND TRENDS...INCLUDING SKY COVER. UPDATES HAVE BEEN
SENT TO THE NDFD AND WEB SERVERS.
&&
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 335 AM EDT THU MAY 30 2013
06Z SFC ANALYSIS SHOWS HIGH PRESSURE TO THE EAST OF KENTUCKY AND DEEP
LOW PRESSURE WELL TO THE NORTHWEST. A SOUTHERN FLOW OF WARMTH AND
MOISTURE CONTINUES THROUGH THE STATE BETWEEN THESE TWO KEY FEATURES.
ON SATELLITE...SOME HIGH CLOUDS AND A SMALLER BATCH OF LOWER ONES ARE
CROSSING EAST KENTUCKY EARLY THIS MORNING. THESE CLOUDS HAVE ONLY
HAD A SMALL IMPACT ON THE RADIATIONAL COOLING THROUGH THE CWA THIS
NIGHT WITH RIDGES STAYING UP IN THE UPPER 60S AND LOWER 70S WHILE THE
MOST SHELTERED VALLEYS CONTINUE THEIR PLUNGE INTO THE UPPER AND
MIDDLE 50S. ALSO SIMILAR TO LAST NIGHT...DEEPER LOCATIONS IN THE
WESTERN PORTIONS OF THE CUMBERLAND VALLEY...WEST OF I-75...ARE
STAYING A BIT MILDER WHEN COMPARED TO VALLEYS FURTHER EAST. AT THE
SAME TIME...DEWPOINTS ARE IN THE LOWER 60S THROUGHOUT THE AREA. WITH
THE VALLEY TEMPS FALLING TO NEAR THEIR DEWPOINTS...DO EXPECT SOME
LIGHT FOG TO DEVELOP IN THE PREDAWN HOURS...BUT STILL BE MAINLY
CONFINED TO THE LOCATIONS ALONG RIVERS AND OTHER BODIES OF WATER.
THE MODELS ARE IN PRETTY GOOD AGREEMENT WITH THE UPPER LEVEL PATTERN
AFFECTING THE REGION THROUGH THE SHORT TERM. THEY ALL SHOW THE
SOUTHEAST RIDGE STRONGLY INFLUENCING EAST KENTUCKY FOR AT LEAST ONE
MORE DAY WHILE A LARGE AREA OF TROUGHING CONSOLIDATES OVER THE HIGH
PLAINS. HEIGHTS WILL START TO FALL LOCALLY LATER TONIGHT AS THE BROAD
TROUGH TO THE NORTHWEST PRESSES IN ON THE WESTERN FRINGES OF THE OHIO
VALLEY. THIS PROCESS WILL BE ACCOMPANIED BY A LEADING BAND OF
SHORTWAVE ENERGY CROSSING INTO THE REGION BY DAWN FRIDAY...JUST NORTH
OF THE OHIO RIVER. THIS BAND WEAKENS DURING THE DAY FRIDAY AS IT
ADVANCES EAST INTO THE RETREATING RIDGE. THE NAM12 AND GFS HAVE
SIMILAR IDEAS WITH THIS FIRST BATCH OF ENERGY AND ITS EFFECT ON
WEATHER SO HAVE GONE WITH A BLEND OF THESE TWO MODELS FOR WX
SPECIFICS THROUGH FRIDAY.
SENSIBLE WEATHER WILL SEE THE WARM AND INCREASINGLY MUGGY AIR MASS
SET THE STAGE FOR MORE IN THE WAY OF CONVECTION TO CLOSE OUT THE WORK
WEEK. HIGHER PW AIR CONTINUES TO BUILD OVER EAST KENTUCKY TODAY AND
FRIDAY. STILL CANNOT RULE OUT SOME STRAY POP UP STORMS LATE THIS
AFTERNOON...MAINLY JUST TO OUR WEST...BUT WITH CHANCES STILL TOO LOW
TO MENTION IN THE ZONES OR REPRESENT IN THE WX GRIDS AT THIS TIME.
THIS IS DESPITE LOW LIS AND MODERATELY HIGH CAPE...AS A TRIGGER WILL
BE HARD TO COME BY UNTIL LATER. A BETTER CHANCE FOR CONVECTION WILL
OCCUR LATER TONIGHT...AGAIN PRIMARILY OVER OUR WESTERN ZONES...AS
THE APPROACHING MID LEVEL WAVE WILL HELP YO ACTIVATE THIS
INCREASINGLY SOUPY AIR MASS. THIS DEVELOPMENT WILL KEEP A DECENT
THREAT OF SHOWERS AND THUNDERSTORMS IN THE FORECAST THROUGHOUT THE
DAY FRIDAY...WORKING WEST TO EAST WITH TIME. THE EXPECTED INCREASE IN
CLOUD COVER AND CONVECTION WILL ALSO LIKELY SERVE TO CAP TEMPERATURES
IN THE MID 80S ON FRIDAY...A TAD LOWER THAN TODAY. BEFORE THE MORE
ORGANIZED AREA OF CONVECTION GETS GOING LATE TONIGHT...DO EXPECT
ANOTHER SMALL TO MODERATE RIDGE AND VALLEY TEMPERATURE SPLIT TO
DEVELOP BY LATE EVENING THOUGH MUCH OF THIS WILL BE WASHED OUT BY THE
LOWER CLOUDS AND SCATTERED COVERAGE OF SHOWERS AND THUNDERSTORMS
TOWARD DAWN FRIDAY.
HAVE USED THE CONSSHORT FOR TD AND WINDS THROUGH THE FIRST 24 HOURS
AS A STARTING POINT...PERSISTENCE FOR HIGHS TODAY AND A MODIFIED
VERSION OF THIS NIGHT/S LOWS FOR TONIGHT. FOR FRIDAY...FAVORED THE
CONSALL FOR HIGHS. DID USE A DIURNAL FROM OBS SCHEME FOR HOURLY T
GRIDS WITH SOME ADJUSTMENTS LATE TONIGHT TO ACCOUNT FOR THE INCREASE
IN CLOUDS AND SCATTERED CONVECTION. AS FOR POPS...KEPT THEM IN LINE
WITH LOW MOS GUIDANCE TODAY BEFORE ENDING UP CLOSER TO THE HIGHER MET
NUMBERS TONIGHT AND THE LOWER MAV ONES ON FRIDAY.
.LONG TERM...(FRIDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 300 AM EDT THU MAY 30 2013
GENERAL AGREEMENT AMONGST THE FORECAST MODELS ONCE AGAIN FOR THE
EXTENDED PERIOD OF THE FORECAST. THE GFS AND ECMWF SOLUTIONS WERE
PREFERRED FOR THIS RENDITION OF THE EXTENDED DUE TO THEIR
SIMILARITIES. THE TIMING OF THE PASSAGE OF A COLD FRONT SATURDAY
NIGHT INTO SUNDAY WAS CAPTURED WELL BY BOTH PREFERRED MODELS. THE
MODELS BOTH HAVE DEVELOPED A SLUGGISH FRONTAL PROGRESSION WHERE THE
FRONT GETS HUNG UP A BIT NORTH OF THE OHIO SATURDAY EVENING. IT
APPEARS THAT THE RIDGE THAT WILL DOMINATE THE WEATHER TODAY AND
TOMORROW WILL BE VERY SLOW TO WEAKEN AND MOVE OFF TO THE EAST. WITH
THIS IN MIND...DECIDED TO MODIFY THE FORECAST TOWARD THE SLOWER
FRONTAL PROGRESSION SEEN IN BOTH THE GFS AND ECMWF. ISOLATED SHOWERS
AND STORMS WILL BE POSSIBLE...AS A WEAK IMPULSE PUSHES ACROSS THE
OHIO VALLEY FRIDAY EVENING. ONCE THIS BIT OF ENERGY EXITS THE AREA
FRIDAY NIGHT...THERE SHOULD ANOTHER LULL IN THE PRECIPITATION...AS
HIGH PRESSURE BECOMES REESTABLISHED ACROSS THE AREA DURING THE DAY
ON SATURDAY. ONCE THE RIDGE FINALLY BREAKS DOWN AND MOVES OFF TO THE
EAST...A COLD FRONT WILL PUSH ACROSS THE OHIO AND TENNESSEE VALLEYS
SATURDAY NIGHT THROUGH SUNDAY NIGHT. WIDESPREAD SHOWERS AND STORMS
ARE LIKELY TO ERUPT ALONG AND JUST IN ADVANCE OF THIS BOUNDARY...AS
MOIST AIR FROM THE GULF OF MEXICO POURS INTO THE AREA ON
SOUTHWESTERLY AND SOUTHERLY WINDS. THE LATEST FORECAST SOUNDINGS
WERE SHOWING MUCH BETTER INSTABILITY AND WIND SHEAR DURING THE DAY
ON SUNDAY...PARTICULARLY DURING THE AFTERNOON AND EVENING HOURS.
WITH CONDITIONS A BIT MORE JUICY AND ENERGETIC...THE POSSIBILITY FOR
A FEW STRONG STORMS WILL EXIST ON SUNDAY...WITH STRONG WINDS AND
HAIL POSSIBLE. THE SOUNDINGS ALSO ARE SHOWING THE POTENTIAL FOR
LOCALLY HEAVY RAINFALL...SO THIS WILL PRESENT THE POSSIBILITY OF
LOCALIZED HYDROLOGY ISSUES WITH THE STRONGER STORMS OR WHERE SHOWERS
AND STORM MOVE REPEATEDLY ACROSS THE SAME AREAS. WITH THE MODELS
BEING IN GOOD AGREEMENT...AND THE MODELS SHOWING FAVORABLE
CONDITIONS FOR SHOWERS AND STORMS TO FORM...WENT VERY CLOSE TO THE
MEXMOS POPS FOR SATURDAY NIGHT AND SUNDAY.
THE PERIOD WILL BEGIN WITH WELL ABOVE NORMAL TEMPERATURES...AS
SOUTHERLY FLOW AHEAD OF THE APPROACHING FRONT BRINGS WARM MOIST AIR
INTO THE AREA IN LARGE QUANTITIES. AFTER THE FRONT PASSES THROUGH
THE AREA LATE SUNDAY NIGHT...A MUCH COOLER AIR MASS WILL FILTER INTO
THE AREA...PAVING THE WAY FOR NORMAL TEMPERATURES MONDAY AND
TUESDAY. HIGHS EACH DAY WILL TOP OUT IN THE MID 70S. TEMPERATURES ON
SUNDAY WILL ALSO BE AROUND NORMAL DUE TO THE INFLUENCE OF
PRECIPITATION AND CLOUD COVER. ANOTHER RIDGE OF HIGH PRESSURE WILL
THEN SETTLE OVER THE REGION ON TUESDAY WEDNESDAY...BRINGING COOLER
AND DRIER WEATHER TO EASTERN KENTUCKY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 127 PM EDT THU MAY 30 2013
HIGH PRESSURE ALONG THE EAST COAST WILL SLIDE SLOWLY EAST WHILE A
CENTER OF LOW PRESSURE MOVES SLOWLY EAST THROUGH THE NORTHERN
PLAINS. A TROUGH OF LOW PRESSURE EXTENDING FROM THE NORTHERN PLAINS
LOW WILL SWING THROUGH THE MID MS VALLEY AND INTO THE GREAT LAKES
BY FRIDAY. THIS LOW PRESSURE TROUGH WILL BRING AN INCREASE IN CLOUD
COVER LATE TONIGHT AND INTO FRIDAY...BUT CEILINGS ACROSS THE REGION
WILL REMAIN VFR. IT APPEARS THAT THE SHOWERS AND THUNDERSTORMS
ASSOCIATED WITH THE LOW PRESSURE TROUGH WILL BE DECAYING AS THEY MOVE
EAST INTO EASTERN KY FRIDAY MORNING AND FOR NOW WILL LEAVE OUT OF THE
TAFS.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...SBH
SHORT TERM...GREIF
LONG TERM...AR
AVIATION...SBH
AREA FORECAST DISCUSSION
NWS JACKSON KY
1037 AM EDT THU MAY 30 2013
.UPDATE...
ISSUED AT 1037 AM EDT THU MAY 30 2013
NDFD AND WEB SERVERS HAVE BEEN UPDATED FOR LATEST SATELLITE AND
SURFACE OBSERVATIONAL TRENDS. ZFP UPDATE NOT NEEDED AT THIS TIME. THE
12Z HRRR POINTS TOWARDS ISOLATED SHOWERS BEING POSSIBLE OVER THE FAR
WESTERN PART OF THE FORECAST AREA FOR A FEW HOURS THIS
AFTERNOON...SIMILAR TO YESTERDAY. EXPECT PROBABILITY TO REMAIN
BELOW 15 PERCENT AND WILL NOT ADD THIS TO FORECAST. THE 12Z NAM
SUPPORTS A DRY FORECAST THIS AFTERNOON....WITH LOW PROBABILITY OF
SHOWERS IN THE WESTERN PART OF THE AREA TONIGHT. THIS IS IN THE CURRENT
FORECAST FOR TONIGHT AND WILL LEAVE AS IS FOR NOW.
UPDATE ISSUED AT 750 AM EDT THU MAY 30 2013
UPDATED THE FORECAST MAINLY TO KEEP THE NEAR TERM GRIDS ON TRACK WITH
THE CURRENT OBS AND TRENDS...INCLUDING SKY COVER. UPDATES HAVE BEEN
SENT TO THE NDFD AND WEB SERVERS.
&&
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 335 AM EDT THU MAY 30 2013
06Z SFC ANALYSIS SHOWS HIGH PRESSURE TO THE EAST OF KENTUCKY AND DEEP
LOW PRESSURE WELL TO THE NORTHWEST. A SOUTHERN FLOW OF WARMTH AND
MOISTURE CONTINUES THROUGH THE STATE BETWEEN THESE TWO KEY FEATURES.
ON SATELLITE...SOME HIGH CLOUDS AND A SMALLER BATCH OF LOWER ONES ARE
CROSSING EAST KENTUCKY EARLY THIS MORNING. THESE CLOUDS HAVE ONLY
HAD A SMALL IMPACT ON THE RADIATIONAL COOLING THROUGH THE CWA THIS
NIGHT WITH RIDGES STAYING UP IN THE UPPER 60S AND LOWER 70S WHILE THE
MOST SHELTERED VALLEYS CONTINUE THEIR PLUNGE INTO THE UPPER AND
MIDDLE 50S. ALSO SIMILAR TO LAST NIGHT...DEEPER LOCATIONS IN THE
WESTERN PORTIONS OF THE CUMBERLAND VALLEY...WEST OF I-75...ARE
STAYING A BIT MILDER WHEN COMPARED TO VALLEYS FURTHER EAST. AT THE
SAME TIME...DEWPOINTS ARE IN THE LOWER 60S THROUGHOUT THE AREA. WITH
THE VALLEY TEMPS FALLING TO NEAR THEIR DEWPOINTS...DO EXPECT SOME
LIGHT FOG TO DEVELOP IN THE PREDAWN HOURS...BUT STILL BE MAINLY
CONFINED TO THE LOCATIONS ALONG RIVERS AND OTHER BODIES OF WATER.
THE MODELS ARE IN PRETTY GOOD AGREEMENT WITH THE UPPER LEVEL PATTERN
AFFECTING THE REGION THROUGH THE SHORT TERM. THEY ALL SHOW THE
SOUTHEAST RIDGE STRONGLY INFLUENCING EAST KENTUCKY FOR AT LEAST ONE
MORE DAY WHILE A LARGE AREA OF TROUGHING CONSOLIDATES OVER THE HIGH
PLAINS. HEIGHTS WILL START TO FALL LOCALLY LATER TONIGHT AS THE BROAD
TROUGH TO THE NORTHWEST PRESSES IN ON THE WESTERN FRINGES OF THE OHIO
VALLEY. THIS PROCESS WILL BE ACCOMPANIED BY A LEADING BAND OF
SHORTWAVE ENERGY CROSSING INTO THE REGION BY DAWN FRIDAY...JUST NORTH
OF THE OHIO RIVER. THIS BAND WEAKENS DURING THE DAY FRIDAY AS IT
ADVANCES EAST INTO THE RETREATING RIDGE. THE NAM12 AND GFS HAVE
SIMILAR IDEAS WITH THIS FIRST BATCH OF ENERGY AND ITS EFFECT ON
WEATHER SO HAVE GONE WITH A BLEND OF THESE TWO MODELS FOR WX
SPECIFICS THROUGH FRIDAY.
SENSIBLE WEATHER WILL SEE THE WARM AND INCREASINGLY MUGGY AIR MASS
SET THE STAGE FOR MORE IN THE WAY OF CONVECTION TO CLOSE OUT THE WORK
WEEK. HIGHER PW AIR CONTINUES TO BUILD OVER EAST KENTUCKY TODAY AND
FRIDAY. STILL CANNOT RULE OUT SOME STRAY POP UP STORMS LATE THIS
AFTERNOON...MAINLY JUST TO OUR WEST...BUT WITH CHANCES STILL TOO LOW
TO MENTION IN THE ZONES OR REPRESENT IN THE WX GRIDS AT THIS TIME.
THIS IS DESPITE LOW LIS AND MODERATELY HIGH CAPE...AS A TRIGGER WILL
BE HARD TO COME BY UNTIL LATER. A BETTER CHANCE FOR CONVECTION WILL
OCCUR LATER TONIGHT...AGAIN PRIMARILY OVER OUR WESTERN ZONES...AS
THE APPROACHING MID LEVEL WAVE WILL HELP YO ACTIVATE THIS
INCREASINGLY SOUPY AIR MASS. THIS DEVELOPMENT WILL KEEP A DECENT
THREAT OF SHOWERS AND THUNDERSTORMS IN THE FORECAST THROUGHOUT THE
DAY FRIDAY...WORKING WEST TO EAST WITH TIME. THE EXPECTED INCREASE IN
CLOUD COVER AND CONVECTION WILL ALSO LIKELY SERVE TO CAP TEMPERATURES
IN THE MID 80S ON FRIDAY...A TAD LOWER THAN TODAY. BEFORE THE MORE
ORGANIZED AREA OF CONVECTION GETS GOING LATE TONIGHT...DO EXPECT
ANOTHER SMALL TO MODERATE RIDGE AND VALLEY TEMPERATURE SPLIT TO
DEVELOP BY LATE EVENING THOUGH MUCH OF THIS WILL BE WASHED OUT BY THE
LOWER CLOUDS AND SCATTERED COVERAGE OF SHOWERS AND THUNDERSTORMS
TOWARD DAWN FRIDAY.
HAVE USED THE CONSSHORT FOR TD AND WINDS THROUGH THE FIRST 24 HOURS
AS A STARTING POINT...PERSISTENCE FOR HIGHS TODAY AND A MODIFIED
VERSION OF THIS NIGHT/S LOWS FOR TONIGHT. FOR FRIDAY...FAVORED THE
CONSALL FOR HIGHS. DID USE A DIURNAL FROM OBS SCHEME FOR HOURLY T
GRIDS WITH SOME ADJUSTMENTS LATE TONIGHT TO ACCOUNT FOR THE INCREASE
IN CLOUDS AND SCATTERED CONVECTION. AS FOR POPS...KEPT THEM IN LINE
WITH LOW MOS GUIDANCE TODAY BEFORE ENDING UP CLOSER TO THE HIGHER MET
NUMBERS TONIGHT AND THE LOWER MAV ONES ON FRIDAY.
.LONG TERM...(FRIDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 300 AM EDT THU MAY 30 2013
GENERAL AGREEMENT AMONGST THE FORECAST MODELS ONCE AGAIN FOR THE
EXTENDED PERIOD OF THE FORECAST. THE GFS AND ECMWF SOLUTIONS WERE
PREFERRED FOR THIS RENDITION OF THE EXTENDED DUE TO THEIR
SIMILARITIES. THE TIMING OF THE PASSAGE OF A COLD FRONT SATURDAY
NIGHT INTO SUNDAY WAS CAPTURED WELL BY BOTH PREFERRED MODELS. THE
MODELS BOTH HAVE DEVELOPED A SLUGGISH FRONTAL PROGRESSION WHERE THE
FRONT GETS HUNG UP A BIT NORTH OF THE OHIO SATURDAY EVENING. IT
APPEARS THAT THE RIDGE THAT WILL DOMINATE THE WEATHER TODAY AND
TOMORROW WILL BE VERY SLOW TO WEAKEN AND MOVE OFF TO THE EAST. WITH
THIS IN MIND...DECIDED TO MODIFY THE FORECAST TOWARD THE SLOWER
FRONTAL PROGRESSION SEEN IN BOTH THE GFS AND ECMWF. ISOLATED SHOWERS
AND STORMS WILL BE POSSIBLE...AS A WEAK IMPULSE PUSHES ACROSS THE
OHIO VALLEY FRIDAY EVENING. ONCE THIS BIT OF ENERGY EXITS THE AREA
FRIDAY NIGHT...THERE SHOULD ANOTHER LULL IN THE PRECIPITATION...AS
HIGH PRESSURE BECOMES REESTABLISHED ACROSS THE AREA DURING THE DAY
ON SATURDAY. ONCE THE RIDGE FINALLY BREAKS DOWN AND MOVES OFF TO THE
EAST...A COLD FRONT WILL PUSH ACROSS THE OHIO AND TENNESSEE VALLEYS
SATURDAY NIGHT THROUGH SUNDAY NIGHT. WIDESPREAD SHOWERS AND STORMS
ARE LIKELY TO ERUPT ALONG AND JUST IN ADVANCE OF THIS BOUNDARY...AS
MOIST AIR FROM THE GULF OF MEXICO POURS INTO THE AREA ON
SOUTHWESTERLY AND SOUTHERLY WINDS. THE LATEST FORECAST SOUNDINGS
WERE SHOWING MUCH BETTER INSTABILITY AND WIND SHEAR DURING THE DAY
ON SUNDAY...PARTICULARLY DURING THE AFTERNOON AND EVENING HOURS.
WITH CONDITIONS A BIT MORE JUICY AND ENERGETIC...THE POSSIBILITY FOR
A FEW STRONG STORMS WILL EXIST ON SUNDAY...WITH STRONG WINDS AND
HAIL POSSIBLE. THE SOUNDINGS ALSO ARE SHOWING THE POTENTIAL FOR
LOCALLY HEAVY RAINFALL...SO THIS WILL PRESENT THE POSSIBILITY OF
LOCALIZED HYDROLOGY ISSUES WITH THE STRONGER STORMS OR WHERE SHOWERS
AND STORM MOVE REPEATEDLY ACROSS THE SAME AREAS. WITH THE MODELS
BEING IN GOOD AGREEMENT...AND THE MODELS SHOWING FAVORABLE
CONDITIONS FOR SHOWERS AND STORMS TO FORM...WENT VERY CLOSE TO THE
MEXMOS POPS FOR SATURDAY NIGHT AND SUNDAY.
THE PERIOD WILL BEGIN WITH WELL ABOVE NORMAL TEMPERATURES...AS
SOUTHERLY FLOW AHEAD OF THE APPROACHING FRONT BRINGS WARM MOIST AIR
INTO THE AREA IN LARGE QUANTITIES. AFTER THE FRONT PASSES THROUGH
THE AREA LATE SUNDAY NIGHT...A MUCH COOLER AIR MASS WILL FILTER INTO
THE AREA...PAVING THE WAY FOR NORMAL TEMPERATURES MONDAY AND
TUESDAY. HIGHS EACH DAY WILL TOP OUT IN THE MID 70S. TEMPERATURES ON
SUNDAY WILL ALSO BE AROUND NORMAL DUE TO THE INFLUENCE OF
PRECIPITATION AND CLOUD COVER. ANOTHER RIDGE OF HIGH PRESSURE WILL
THEN SETTLE OVER THE REGION ON TUESDAY WEDNESDAY...BRINGING COOLER
AND DRIER WEATHER TO EASTERN KENTUCKY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 755 AM EDT THU MAY 30 2013
VFR CONDITIONS ARE EXPECTED TO PREVAIL THROUGH THE END OF THE PERIOD
AT ALL THREE TAF SITES. SOME SCT CU IN THE 5 TO 7K FT RANGE ALONG
WITH HIGH CLOUDS WILL LIKELY WORK THEIR WAY BACK IN ACROSS THE
WESTERN TAF SITES DURING THE MORNING AS HIGHER 850MB MOISTURE
ADVECTS IN ALONG WITH DIURNAL HEATING TAKING EFFECT. BY MIDDAY...
EXPECT ENOUGH CLOUDS AROUND 5-7K FEET TO GO WITH BKN CIGS INTO EARLY
EVENING ACROSS THE AREA BEFORE TEMPORARILY SCATTERING OUT. THE
APPROACH OF A MID LEVEL SHORT WAVE LOOKS TO BE ENOUGH TO GENERATE A
BATCH OF SHOWERS AND THUNDERSTORMS TOWARD DAWN...HAVE ADDED A VCTS
FOR THIS TO ALL THE TAFS. WINDS THROUGH THE PERIOD WILL BE RATHER
LIGHT WITH PEAK SPEEDS OCCURRING AROUND MID AFTERNOON AT NEAR 10 KTS
FROM THE SOUTH.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...SBH
SHORT TERM...GREIF
LONG TERM...AR
AVIATION...GREIF
AREA FORECAST DISCUSSION
NWS CARIBOU ME
1054 PM EDT FRI MAY 31 2013
.SYNOPSIS...
A COLD FRONT WILL DROP SOUTH INTO NORTHERN MAINE TONIGHT. THE
FRONT WILL LIFT BACK TO THE NORTH AS A WARM FRONT LATE SATURDAY
NIGHT. A STRONG COLD FRONT WILL APPROACH FROM THE WEST LATE IN THE
DAY SUNDAY AND VERY SLOWLY CROSS THE REGION SUNDAY NIGHT THROUGH
MONDAY NIGHT.
&&
.NEAR TERM /THROUGH SATURDAY/...
1045 PM UPDATE: BASED ON FOG BEING REPORTED AT KFVE AIRPORT...WE
WENT AHEAD AND PLACED PATCHY FOG IN THE NRN PORTION OF THE FA
HAVEN RECEIVED CNVCTV RNFL FROM THE MCS THAT CROSSED THE REGION
EARLIER THIS EVE. THE REST OF THE NEAR TERM FCST REMAINS UNCHGD
FROM LAST UPDATE.
845 PM UPDATE: MOST...IF NOT ALL OF THE STRONG TSTM ACTIVITY HAS
WEAKENED ACROSS OUR FA...SO WE DROPPED THE ENHANCED TSTM WORDING
AND KEEP MENTION OF TSTMS IN FCST TIL ABOUT MDNGT. AN AREA OF MORE
STRATIFORM RNFL BEHIND WHATS LEFT THE LEADING CNVCTN IS STILL
CONTG OVR NRN PTNS OF THE FA THIS EVE...BUT THIS TOO SHOULD
GRADUALLY WIND DOWN BY LATE TNGT. ONLY OTHER CHG WAS TO LOWER
OVRNGT LOWS ACROSS THE N POSTED AT 5 AM SAT DUE TO 8 PM OBS ALREADY
CLOSE TO PRIOR LOWS DUE TO RN COOLED AIR. WITH MID CLD CVR XPCTD
TO CONT SPCLY ACROSS THE N...WE DID NOT INCLUDE PATCHY FOG FOR
LATE TNGT OVR AREAS THAT HAVE EXPERIENCED RNFL THIS EVE...BUT THIS
CANNOT BE RULED OUT IF BREAKS IN THE MID CLD CVR OCCUR AFT MDNGT.
515 PM UPDATE: WE UPDATED POPS TO INCREASE TO CATEGORICAL RANGE
FOR NRN ME TO ACCOUNT FOR THE LN OF TSTMS MOVG IN FROM QB.
ENHANCED WORDING FOR DAMAGING WINDS...HAIL AND HEAVY DOWNPOURS
WERE INCLUDED TIL 11 PM...AT WHICH POINT...THE HRRR MODEL INDICATES
THAT MOST OF THE STRONG TSTM ELEMENTS WILL HAVE MOVED SE INTO NB.
ALSO UPDATED QPF FOR THE 18-24Z AND 00-06Z TM FRAMES TNGT TO
INCREASE TO CVR CONVECTIVE RNFL RATES WITH THIS LN. 1-3 HR FLASH
FLOOD GUIDANCE IS ONLY ABOUT 1.50 INCHES FOR MOST OF NRN ME...SO
WE WILL BE MONITORING FOR POSSIBLE LCLZD FLOODING AS WELL.
ORGNL DISC: A VERY WARM AND HUMID AIR MASS WILL REMAIN IN PLACE
THROUGH TONIGHT. A COLD FRONT WILL SAG SOUTHWARD OUT OF QUEBEC
INTO THE SAINT JOHN VALLEY THIS EVENING AND BRING THE THREAT OF
STRONG OR SEVERE THUNDERSTORMS WITH DAMAGING WINDS AND SMALL HAIL.
WITH STRONG WINDS ALOFT AND FAST STORM MOTIONS...SOME BOWING LINE
SEGMENTS ARE POSSIBLE AS THIS CONVECTION ENTERS THE NORTHERN END
OF THE CWA THIS EVENING. DOWNED TREES WERE ALREADY REPORTED WITH A
WEAKER THUNDERSTORM IN FORT KENT THIS AFTERNOON. DEEPER STORMS MAY
ALLOW FOR UP TO QUARTER SIZE HAIL BRIEFLY. WITH PWATS OVER ONE AND
HALF INCH...HEAVY DOWNPOURS ARE EXPECTED. THESE STORMS COULD REACH
40K FT. THE SEVERE WEATHER THREAT SHOULD BE RESTRICTED PRIMARILY
TO ZONES ONE AND TWO IN NORTHERN AROOSTOOK WITH STORMS WEAKENING
BY THE TIME THEY REACH HOULTON LATER THIS EVENING.
ELSEWHERE IN THE FORECAST AREA...AIR MASS THUNDERSTORMS WILL END
LATER THIS AFTERNOON AND A WARM AND HUMID NIGHT IS EXPECTED WITH
LOWS IN THE UPPER 60S FOR DOWN EAST AND AROUND BANGOR. LOWS WILL
BE IN THE LOW 60S TOWARDS THE CROWN OF MAINE. THE COLD FRONT WILL
STALL IN NORTHERN MAINE WITH CLOUD COVER AND THUNDERSTORMS
PERSISTING WELL INTO THE NIGHT.
&&
.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/...
ACTIVE WEATHER IS EXPECTED DURING THE SHORT TERM WITH THE MAIN
CONCERNS THE POTENTIAL FOR STRONG TO SEVERE THUNDERSTORMS AND FLASH
FLOODING.
A FRONTAL BOUNDARY IS EXPECTED TO STRETCH ACROSS THE CENTRAL
PORTION OF THE CWA SAT EVENING. THE FRONT SHOULD LIFT BACK TO THE
NORTH AS A WARM FRONT SAT NIGHT AND SHOULD BE ACCOMPANIED BY
SHOWERS AND EMBEDDED THUNDERSTORMS...ESPECIALLY ACROSS THE
NORTHERN HALF OF THE AREA. PRECIPITABLE H20 IS PROGGED TO BE
AROUND 1.6-1.8 INCHES WHICH IS NEAR RECORD LEVELS FOR JUNE 1ST.
SHOWERS AND THUNDERSTORMS SAT NIGHT WILL HAVE THE POTENTIAL OF
PRODUCING HEAVY DOWNPOURS...AND DURING THE EVENING GUSTY WIND AND
SMALL HAIL. A STRONG COLD FRONT WILL APPROACH THE WESTERN BORDER
OF MAINE LATE IN THE DAY SUNDAY. THE MODELS DIFFER ON THE AMOUNT
OF INSTABILITY THAT WILL BE AVAILABLE SUN PM...AND MUCH WILL
DEPEND ON CLOUD COVER/PRE-EXISTING SHOWERS THAT COULD LIMIT JUST
HOW UNSTABLE IT BECOMES DURING THE AFTERNOON. THE MODELS DO
INDICATE ENOUGH CAPE AND SHEAR THAT SEVERE STORMS WILL BE POSSIBLE
DURING THE AFTERNOON/EVENING. THE HIGH PWATS ALSO MEAN THAT HEAVY
DOWNPOURS AND FLASH FLOODING WILL BE CONCERNS TOO...ESPECIALLY
GIVEN HOW SATURATED THE GROUND IS FROM THE RECENT HEAVY RAINS. THE
ENHANCED WORDING THAT THE MIDNIGHT CREW HAD IN LOOKS REAL GOOD AND
THE ONLY CHANGE WAS TO ADD THE LOCALLY HEAVY RAIN WORDING FOR SUN
PM/EVE. THE COLD FRONT IS EXPECTED TO ONLY VERY SLOWLY MOVE ACROSS
THE CWA SUN NIGHT AND MON AND MAY ONLY BE ON A HOULTON-BANGOR LINE
BY MON EVENING. THE BEST CHANCE OF SHOWERS AND THUNDERSTORMS
MONDAY WILL LIKELY BE ACROSS THE SOUTHEAST OF THE CWA WITH SOME
DRYING TO BEGIN TO WORK INTO THE WESTERN ZONES. WILL AGAIN MENTION
HEAVY RAIN POSSIBLE ACROSS THE SOUTHEAST HALF OF THE CWA. WILL
HOLD OFF ON ANY ENHANCED SEVERE WEATHER LANGUAGE AS IT IS IN DAY
THREE. THE SPC DOES HAVE MUCH OF THE AREA IN A SLIGHT RISK FOR DAY
3.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
THE EXTENDED MODELS CONTINUE TO BE IN GOOD AGREEMENT THROUGH THE
EARLY AND MID PORTIONS OF THE EXTENDED. A LOW PRESSURE SYSTEM SE
OF JAMES BAY...WITH AN ASSOCIATED FRONTAL SYSTEM EXTENDING SOUTH
THROUGH DOWNEAST MAINE...THEN SOUTH ALONG THE ATLANTIC COAST. A
BERMUDA HIGH PRESSURE SYSTEM RIDGED INTO THE COAST...A SECOND HIGH
PRESSURE SYSTEM BUILDING SE OUT OF WRN CANADA. BY THE START OF THE
EXTENDED PERIOD THE NRN PORTIONS OF THE FRONT CONTINUES TO REMAIN
UNDER THE UPPER LEVEL RIDGE...THE SRN PORTION HOWEVER WILL BEGIN
TO MOVE OUT AS THE UPPER TROUGH MOVES TO THE EAST SIDE OF THE
APPALACHIANS. BOTH MODELS INDICATE A SECONDARY LOW DEVELOPING
ALONG COAST VA WHICH WILL ASSIST WITH THE EASTWARD MOVEMENT OF
THE FRONT. BY WED MRNG THE FRONT WILL BE WELL EAST OF THE
AREA...AND HIGHER PRESSURE WILL BUILD INTO MAINE. THE HIGH
PRESSURE RIDGE WILL REMAIN IN PLACE THROUGH AT LEAST FRI MRNG. FRI
MRNG A NEW LOW PRESSURE SYSTEM WILL BE CENTERED OVER THE GREAT
LAKES...WITH ITS SUPPORTING UPPER LOW OVER CENTRAL MANITOBA. THE
GFS SHOWS A WARM FRONT EXTENDED EAST INTO WRN MAINE. THE ECMWF FRI
MRNG MAINTAINS THE HIGH PRESSURE RIDGE WITH NO APPARENT WARM FRONT
ASSOCIATED WITH THE FRONT. BY FRI EVENING THE ECMWF SYSTEM BECOMES
A BIT MORE ORGANIZED WITH ITS UPPER LOW MOVING TO SW JAMES BAY.
BY SAT MRNG BOTH MODELS MOVE THE SHOWERS ASSOCIATED WITH THE LOW
INTO MAINE.
STARTED WITH A BASE OF GMOS...OVER LAID A BLEND OF OFFICIAL/ALL
MODEL BLEND FOR WNDS/POPS/SKY/MAX/MIN. ADDED 15 PERCENT TO WINDS
FOR GUSTS OVER LAND...25 PERCENT TO WINDS OVER COASTAL WATERS.
&&
.AVIATION /21Z FRIDAY THROUGH WEDNESDAY/...
NEAR TERM: VFR OUTSIDE OF THUNDERSTORMS LATE THIS AFTERNOON AND
EVENING. THUNDERSTORMS COULD BE SEVERE TOWARDS CAR...PQI AND FVE THIS
EVENING WITH DAMAGING WINDS AND SMALL HAIL. THE FRONT WILL STALL
AND COULD PRODUCE IFR VIS AND CIGS FROM PQI NORTHWARD INTO EARLY
SATURDAY MORNING. OTHERWISE...VFR CONDITIONS ARE EXPECTED.
SHORT TERM: VFR MUCH OF THE TIME SAT NIGHT THROUGH MONDAY...BUT A
PERIOD OF MVFR TO IFR POSSIBLE SAT NIGHT FROM KHUL NORTH IN SHOWERS
AND THUNDERSTORMS. ADDITIONAL PERIODS OF MVFR AND BRIEF IFR
POSSIBLE IN ANY NEAR CONVECTION SUN PM AND AGAIN MONDAY. STRONG AND
ERRATIC WIND GUSTS AND HAIL WILL BE POSSIBLE IN/NEAR THE STRONGEST
CONVECTION.
&&
.MARINE...
NEAR TERM: FOG IS EXPECTED TO RETURN LATER TONIGHT AND TOMORROW ON
THE WATERS. OTHERWISE...STABLE CONDITIONS MEAN LIGHT WINDS AND A
SOUTH SWELL AROUND 2 TO 3 FEET.
SHORT TERM: A SW WIND WILL PICK UP OUT AHEAD OF A COLD FRONT SUNDAY
AND MAY REACH SCA LEVELS BY SUN PM AND CONTINUE INTO MONDAY. THE
SEAS WILL LIKELY REACH SCA LEVELS BY SUNDAY AFTERNOON AND CONTINUE
INTO MONDAY WITH A SOUTH SWELL AND A COMBINED SEA/SWELL OF 8-10 FEET
EXPECTED BY SUNDAY NIGHT.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...VJN
SHORT TERM...CB
LONG TERM...NORTON
AVIATION...VJN/CB
MARINE...VJN/CB
AREA FORECAST DISCUSSION
NWS CARIBOU ME
903 PM EDT FRI MAY 31 2013
.SYNOPSIS...
A COLD FRONT WILL DROP SOUTH INTO NORTHERN MAINE TONIGHT. THE
FRONT WILL LIFT BACK TO THE NORTH AS A WARM FRONT LATE SATURDAY
NIGHT. A STRONG COLD FRONT WILL APPROACH FROM THE WEST LATE IN THE
DAY SUNDAY AND VERY SLOWLY CROSS THE REGION SUNDAY NIGHT THROUGH
MONDAY NIGHT.
&&
.NEAR TERM /THROUGH SATURDAY/...
845 PM UPDATE: MOST...IF NOT ALL OF THE STRONG TSTM ACTIVITY HAS
WEAKENED ACROSS OUR FA...SO WE DROPPED THE ENHANCED TSTM WORDING
AND KEEP MENTION OF TSTMS IN FCST TIL ABOUT MDNGT. AN AREA OF MORE
STRATIFORM RNFL BEHIND WHATS LEFT THE LEADING CNVCTN IS STILL
CONTG OVR NRN PTNS OF THE FA THIS EVE...BUT THIS TOO SHOULD
GRADUALLY WIND DOWN BY LATE TNGT. ONLY OTHER CHG WAS TO LOWER
OVRNGT LOWS ACROSS THE N POSTED AT 5 AM SAT DUE TO 8 PM OBS ALREADY
CLOSE TO PRIOR LOWS DUE TO RN COOLED AIR. WITH MID CLD CVR XPCTD
TO CONT SPCLY ACROSS THE N...WE DID NOT INCLUDE PATCHY FOG FOR
LATE TNGT OVR AREAS THAT HAVE EXPERIENCED RNFL THIS EVE...BUT THIS
CANNOT BE RULED OUT IF BREAKS IN THE MID CLD CVR OCCUR AFT MDNGT.
515 PM UPDATE: WE UPDATED POPS TO INCREASE TO CATEGORICAL RANGE
FOR NRN ME TO ACCOUNT FOR THE LN OF TSTMS MOVG IN FROM QB.
ENHANCED WORDING FOR DAMAGING WINDS...HAIL AND HEAVY DOWNPOURS
WERE INCLUDED TIL 11 PM...AT WHICH POINT...THE HRRR MODEL INDICATES
THAT MOST OF THE STRONG TSTM ELEMENTS WILL HAVE MOVED SE INTO NB.
ALSO UPDATED QPF FOR THE 18-24Z AND 00-06Z TM FRAMES TNGT TO
INCREASE TO CVR CONVECTIVE RNFL RATES WITH THIS LN. 1-3 HR FLASH
FLOOD GUIDANCE IS ONLY ABOUT 1.50 INCHES FOR MOST OF NRN ME...SO
WE WILL BE MONITORING FOR POSSIBLE LCLZD FLOODING AS WELL.
ORGNL DISC: A VERY WARM AND HUMID AIR MASS WILL REMAIN IN PLACE
THROUGH TONIGHT. A COLD FRONT WILL SAG SOUTHWARD OUT OF QUEBEC
INTO THE SAINT JOHN VALLEY THIS EVENING AND BRING THE THREAT OF
STRONG OR SEVERE THUNDERSTORMS WITH DAMAGING WINDS AND SMALL HAIL.
WITH STRONG WINDS ALOFT AND FAST STORM MOTIONS...SOME BOWING LINE
SEGMENTS ARE POSSIBLE AS THIS CONVECTION ENTERS THE NORTHERN END
OF THE CWA THIS EVENING. DOWNED TREES WERE ALREADY REPORTED WITH A
WEAKER THUNDERSTORM IN FORT KENT THIS AFTERNOON. DEEPER STORMS MAY
ALLOW FOR UP TO QUARTER SIZE HAIL BRIEFLY. WITH PWATS OVER ONE AND
HALF INCH...HEAVY DOWNPOURS ARE EXPECTED. THESE STORMS COULD REACH
40K FT. THE SEVERE WEATHER THREAT SHOULD BE RESTRICTED PRIMARILY
TO ZONES ONE AND TWO IN NORTHERN AROOSTOOK WITH STORMS WEAKENING
BY THE TIME THEY REACH HOULTON LATER THIS EVENING.
ELSEWHERE IN THE FORECAST AREA...AIR MASS THUNDERSTORMS WILL END
LATER THIS AFTERNOON AND A WARM AND HUMID NIGHT IS EXPECTED WITH
LOWS IN THE UPPER 60S FOR DOWN EAST AND AROUND BANGOR. LOWS WILL
BE IN THE LOW 60S TOWARDS THE CROWN OF MAINE. THE COLD FRONT WILL
STALL IN NORTHERN MAINE WITH CLOUD COVER AND THUNDERSTORMS
PERSISTING WELL INTO THE NIGHT.
&&
.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/...
ACTIVE WEATHER IS EXPECTED DURING THE SHORT TERM WITH THE MAIN
CONCERNS THE POTENTIAL FOR STRONG TO SEVERE THUNDERSTORMS AND FLASH
FLOODING.
A FRONTAL BOUNDARY IS EXPECTED TO STRETCH ACROSS THE CENTRAL
PORTION OF THE CWA SAT EVENING. THE FRONT SHOULD LIFT BACK TO THE
NORTH AS A WARM FRONT SAT NIGHT AND SHOULD BE ACCOMPANIED BY
SHOWERS AND EMBEDDED THUNDERSTORMS...ESPECIALLY ACROSS THE
NORTHERN HALF OF THE AREA. PRECIPITABLE H20 IS PROGGED TO BE
AROUND 1.6-1.8 INCHES WHICH IS NEAR RECORD LEVELS FOR JUNE 1ST.
SHOWERS AND THUNDERSTORMS SAT NIGHT WILL HAVE THE POTENTIAL OF
PRODUCING HEAVY DOWNPOURS...AND DURING THE EVENING GUSTY WIND AND
SMALL HAIL. A STRONG COLD FRONT WILL APPROACH THE WESTERN BORDER
OF MAINE LATE IN THE DAY SUNDAY. THE MODELS DIFFER ON THE AMOUNT
OF INSTABILITY THAT WILL BE AVAILABLE SUN PM...AND MUCH WILL
DEPEND ON CLOUD COVER/PRE-EXISTING SHOWERS THAT COULD LIMIT JUST
HOW UNSTABLE IT BECOMES DURING THE AFTERNOON. THE MODELS DO
INDICATE ENOUGH CAPE AND SHEAR THAT SEVERE STORMS WILL BE POSSIBLE
DURING THE AFTERNOON/EVENING. THE HIGH PWATS ALSO MEAN THAT HEAVY
DOWNPOURS AND FLASH FLOODING WILL BE CONCERNS TOO...ESPECIALLY
GIVEN HOW SATURATED THE GROUND IS FROM THE RECENT HEAVY RAINS. THE
ENHANCED WORDING THAT THE MIDNIGHT CREW HAD IN LOOKS REAL GOOD AND
THE ONLY CHANGE WAS TO ADD THE LOCALLY HEAVY RAIN WORDING FOR SUN
PM/EVE. THE COLD FRONT IS EXPECTED TO ONLY VERY SLOWLY MOVE ACROSS
THE CWA SUN NIGHT AND MON AND MAY ONLY BE ON A HOULTON-BANGOR LINE
BY MON EVENING. THE BEST CHANCE OF SHOWERS AND THUNDERSTORMS
MONDAY WILL LIKELY BE ACROSS THE SOUTHEAST OF THE CWA WITH SOME
DRYING TO BEGIN TO WORK INTO THE WESTERN ZONES. WILL AGAIN MENTION
HEAVY RAIN POSSIBLE ACROSS THE SOUTHEAST HALF OF THE CWA. WILL
HOLD OFF ON ANY ENHANCED SEVERE WEATHER LANGUAGE AS IT IS IN DAY
THREE. THE SPC DOES HAVE MUCH OF THE AREA IN A SLIGHT RISK FOR DAY
3.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
THE EXTENDED MODELS CONTINUE TO BE IN GOOD AGREEMENT THROUGH THE
EARLY AND MID PORTIONS OF THE EXTENDED. A LOW PRESSURE SYSTEM SE
OF JAMES BAY...WITH AN ASSOCIATED FRONTAL SYSTEM EXTENDING SOUTH
THROUGH DOWNEAST MAINE...THEN SOUTH ALONG THE ATLANTIC COAST. A
BERMUDA HIGH PRESSURE SYSTEM RIDGED INTO THE COAST...A SECOND HIGH
PRESSURE SYSTEM BUILDING SE OUT OF WRN CANADA. BY THE START OF THE
EXTENDED PERIOD THE NRN PORTIONS OF THE FRONT CONTINUES TO REMAIN
UNDER THE UPPER LEVEL RIDGE...THE SRN PORTION HOWEVER WILL BEGIN
TO MOVE OUT AS THE UPPER TROUGH MOVES TO THE EAST SIDE OF THE
APPALACHIANS. BOTH MODELS INDICATE A SECONDARY LOW DEVELOPING
ALONG COAST VA WHICH WILL ASSIST WITH THE EASTWARD MOVEMENT OF
THE FRONT. BY WED MRNG THE FRONT WILL BE WELL EAST OF THE
AREA...AND HIGHER PRESSURE WILL BUILD INTO MAINE. THE HIGH
PRESSURE RIDGE WILL REMAIN IN PLACE THROUGH AT LEAST FRI MRNG. FRI
MRNG A NEW LOW PRESSURE SYSTEM WILL BE CENTERED OVER THE GREAT
LAKES...WITH ITS SUPPORTING UPPER LOW OVER CENTRAL MANITOBA. THE
GFS SHOWS A WARM FRONT EXTENDED EAST INTO WRN MAINE. THE ECMWF FRI
MRNG MAINTAINS THE HIGH PRESSURE RIDGE WITH NO APPARENT WARM FRONT
ASSOCIATED WITH THE FRONT. BY FRI EVENING THE ECMWF SYSTEM BECOMES
A BIT MORE ORGANIZED WITH ITS UPPER LOW MOVING TO SW JAMES BAY.
BY SAT MRNG BOTH MODELS MOVE THE SHOWERS ASSOCIATED WITH THE LOW
INTO MAINE.
STARTED WITH A BASE OF GMOS...OVER LAID A BLEND OF OFFICIAL/ALL
MODEL BLEND FOR WNDS/POPS/SKY/MAX/MIN. ADDED 15 PERCENT TO WINDS
FOR GUSTS OVER LAND...25 PERCENT TO WINDS OVER COASTAL WATERS.
&&
.AVIATION /21Z FRIDAY THROUGH WEDNESDAY/...
NEAR TERM: VFR OUTSIDE OF THUNDERSTORMS LATE THIS AFTERNOON AND
EVENING. THUNDERSTORMS COULD BE SEVERE TOWARDS CAR...PQI AND FVE THIS
EVENING WITH DAMAGING WINDS AND SMALL HAIL. THE FRONT WILL STALL
AND COULD PRODUCE IFR VIS AND CIGS FROM PQI NORTHWARD INTO EARLY
SATURDAY MORNING. OTHERWISE...VFR CONDITIONS ARE EXPECTED.
SHORT TERM: VFR MUCH OF THE TIME SAT NIGHT THROUGH MONDAY...BUT A
PERIOD OF MVFR TO IFR POSSIBLE SAT NIGHT FROM KHUL NORTH IN SHOWERS
AND THUNDERSTORMS. ADDITIONAL PERIODS OF MVFR AND BRIEF IFR
POSSIBLE IN ANY NEAR CONVECTION SUN PM AND AGAIN MONDAY. STRONG AND
ERRATIC WIND GUSTS AND HAIL WILL BE POSSIBLE IN/NEAR THE STRONGEST
CONVECTION.
&&
.MARINE...
NEAR TERM: FOG IS EXPECTED TO RETURN LATER TONIGHT AND TOMORROW ON
THE WATERS. OTHERWISE...STABLE CONDITIONS MEAN LIGHT WINDS AND A
SOUTH SWELL AROUND 2 TO 3 FEET.
SHORT TERM: A SW WIND WILL PICK UP OUT AHEAD OF A COLD FRONT SUNDAY
AND MAY REACH SCA LEVELS BY SUN PM AND CONTINUE INTO MONDAY. THE
SEAS WILL LIKELY REACH SCA LEVELS BY SUNDAY AFTERNOON AND CONTINUE
INTO MONDAY WITH A SOUTH SWELL AND A COMBINED SEA/SWELL OF 8-10 FEET
EXPECTED BY SUNDAY NIGHT.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...VJN
SHORT TERM...CB
LONG TERM...NORTON
AVIATION...VJN/CB
MARINE...VJN/CB
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
902 PM EDT FRI MAY 31 2013
.SYNOPSIS...
WARM AND HUMID CONDITIONS WILL CONTINUE THROUGH SATURDAY. A COLD
FRONT WILL BRING SHOWERS AND THUNDERSTORMS SATURDAY NIGHT INTO
SUNDAY. HIGH PRESSURE TAKES CHARGE NEXT WEEK PROVIDING DRY AND
LESS HUMID WEATHER.
&&
.NEAR TERM /THROUGH SATURDAY/...
AN INTERESTING INTERACTION BETWEEN MID-LEVEL INSTABILITY BEING
LARGELY HARNESSED BY AN INCOMING VORT MAXIMA AND PRE-CONVECTIVE
BOUNDARY LAYER DRIVEN OUTFLOW ORIGINATING CONVECTIVE ACTIVITY
CONTINUES TO TAKE PLACE OVER SOUTHEASTERN OHIO THIS EVENING. THE
NORTHERN TWO-THIRDS OF THE ACTIVITY IS LARGELY BEING DRIVEN FROM
ALOFT...RESULTING IN MEAGER WIND GUSTS WITH THE CONVECTIVE SYSTEM
MOVING THROUGH OHIO. THE SOUTHERN PORTIONS OF THE ACTIVITY STILL
ARE MANAGING TO CHANNEL SOME SURFACE BASED INSTABILITY...LEADING
TO MORE WIND GUSTS WITH THE ACTIVITY. AS THE EVENING
CONTINUES...THIS SHOULD ALL TREND TOWARD BEING MID-LEVEL
DRIVEN...AND WIND GUSTS EVERYWHERE SHOULD START TO TAPER OFF
TOWARD 20 MPH. HOWEVER...NOW BOTH LESS FINE SCALE MODELS SUCH AS
THE NAM AS WELL AS THE LATE ARRIVING TO THE PARTY HIGH RES MODELS
SUCH AS THE HRRR ARE ADVERTISING THIS ACTIVITY MANAGING TO MAKE
ITS WAY ACROSS THE ENTIRE AREA IN A LESS DEVELOPED FORM OVERNIGHT.
BECAUSE OF THIS...POPS WERE AGAIN INCREASED ACROSS A VAST SWATH OF
THE AREA...INCLUDING METROPOLITAN PITTSBURGH. IT WOULD STAND TO
REASON THAT THUNDER WILL BE A DIMINISHING THREAT...SO IT WAS
LARGELY REMOVED FROM THE FORECAST AFTER MIDNIGHT AS WELL.
ONCE THIS MID-LEVEL SYSTEM PASSES...A PERIOD OF DRY CONDITIONS
WILL BE LIKELY BEFORE THE CHANCES OF SHOWERS AND THUNDERSTORMS
AGAIN START TO INCREASE FROM WEST TO EAST ON SATURDAY. FRIES
&&
.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/...
BY SATURDAY NIGHT...OVERALL WIND FIELD/SHEAR VALUES WL BE ON THE
INCRS AS WEAKENING UPR TROF APPRCHES THE WRN LAKES. LATEST GFS AND
NAM SOLNS INDICATE OVRNGT SHRTWV/JET STREAK PROGRESSING ACRS THE
UPR OH REGION. GIVEN THE CONSISTENT NATURE OF THIS OVR THE PAST
CPL OF DAYS...HAVE UPPED PCPN PROBS TO THE LIKELY CATEGORY FOR
PASSAGE OF THE FEATURE. LATE NGT TIMING FAVORS DIMINISHED
INSTABILITY...HENCE SEVERE THREAT LKS MINIMAL.
CDFNT RMNS MDL-POISED FOR A SUNDAY PASSAGE AND LIKELY POPS WERE
HEDGED AND TAPERED OFF WITH TIMING DIFFERENCES RMNG IN TDAS SOLNS.
NEVERTHELESS...FRONTAL PASSAGE WL END THE PCPN POTENTIAL AND DRIVE
MONDAY TEMPS BACK TO...OR A FEW DEGREES BLO THE SEASONAL AVERAGES.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
MDLS ARE IN AGREEMENT IN DEPICTIONS OF A LOW AMPLITUDE MIDWEST
RIDGE AND ERN CONUS TROF FOR THE EARLY WEEK PTN. DRY WX IS THUS
FORECAST WITH COOL TEMPS.
AS THE WEEK PROGRESSES...A TEMP MODERATION CAN BE EXPECTED AS
DVLPG UPR MS VALLEY LOW INITIATES WARM ADVCTN OVR THE REGION. EWD
EVOLUTION OF THE LOW WL THEN HERALD AN INCRS IN POPS AS THE WEEK
DRAWS TO A CLOSE.
HPC NMBRS WERE REASONABLE FOR THE ENTIRE SCENARIO AND ONLY MINOR
ADJUSTMENTS WERE NEEDED TO THAT GUIDANCE.
&&
.AVIATION /01Z SATURDAY THROUGH WEDNESDAY/...
A WEAK UPPER LEVEL DISTURBANCE CURRENTLY CROSSING THE OHIO VALLEY
WILL BRING SHOWERS TO THE MAJORITY OF THE TERMINALS EARLY TONIGHT...OTHERWISE...VFR
CONDITIONS WILL PERSIST AS WEAK HIGH PRESSURE SLOWLY PUSHES TO
THE EAST. ANOTHER UPPER LEVEL DISTURBANCE WILL MOVE OVER THE
REGION SATURDAY BUT CONFIDENCE IS NOT HIGH ENOUGH TO INTRODUCE TS
INTO TAFS. DID INTRODUCE GUSTS IN ALL SITES TOMORROW AFTERNOON AS
PRESSURE GRADIENT TIGHTENS WITH APPROACHING FRONT.
.OUTLOOK.../SATURDAY NIGHT THROUGH WEDNESDAY/...
BRIEF IFR RESTRICTIONS ARE LIKELY AHEAD AND ALONG A COLD FRONT
SATURDAY NIGHT INTO SUNDAY WITH RAIN. HIGH PRESSURE WILL RETURN
LATE SUNDAY NIGHT THROUGH WEDNESDAY...GIVING WAY TO VFR CONDITIONS.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
848 PM EDT FRI MAY 31 2013
.SYNOPSIS...
WARM AND HUMID CONDITIONS WILL CONTINUE THROUGH SATURDAY. A COLD
FRONT WILL BRING SHOWERS AND THUNDERSTORMS SATURDAY NIGHT INTO
SUNDAY. HIGH PRESSURE TAKES CHARGE NEXT WEEK PROVIDING DRY AND
LESS HUMID WEATHER.
&&
.NEAR TERM /THROUGH SATURDAY/...
AN INTERESTING INTERACTION BETWEEN MID-LEVEL INSTABILITY BEING
LARGELY HARNESSED BY AN INCOMING VORT MAXIMA AND PRE-CONVECTIVE
BOUNDARY LAYER DRIVEN OUTFLOW ORIGINATING CONVECTIVE ACTIVITY
CONTINUES TO TAKE PLACE OVER SOUTHEASTERN OHIO THIS EVENING. THE
NORTHERN TWO-THIRDS OF THE ACTIVITY IS LARGELY BEING DRIVEN FROM
ALOFT...RESULTING IN MEAGER WIND GUSTS WITH THE CONVECTIVE SYSTEM
MOVING THROUGH OHIO. THE SOUTHERN PORTIONS OF THE ACTIVITY STILL
ARE MANAGING TO CHANNEL SOME SURFACE BASED INSTABILITY...LEADING
TO MORE WIND GUSTS WITH THE ACTIVITY. AS THE EVENING
CONTINUES...THIS SHOULD ALL TREND TOWARD BEING MID-LEVEL
DRIVEN...AND WIND GUSTS EVERYWHERE SHOULD START TO TAPER OFF
TOWARD 20 MPH. HOWEVER...NOW BOTH LESS FINE SCALE MODELS SUCH AS
THE NAM AS WELL AS THE LATE ARRIVING TO THE PARTY HIGH RES MODELS
SUCH AS THE HRRR ARE ADVERTISING THIS ACTIVITY MANAGING TO MAKE
ITS WAY ACROSS THE ENTIRE AREA IN A LESS DEVELOPED FORM OVERNIGHT.
BECAUSE OF THIS...POPS WERE AGAIN INCREASED ACROSS A VAST SWATH OF
THE AREA...INCLUDING METROPOLITAN PITTSBURGH. IT WOULD STAND TO
REASON THAT THUNDER WILL BE A DIMINISHING THREAT...SO IT WAS
LARGELY REMOVED FROM THE FORECAST AFTER MIDNIGHT AS WELL.
ONCE THIS MID-LEVEL SYSTEM PASSES...A PERIOD OF DRY CONDITIONS
WILL BE LIKELY BEFORE THE CHANCES OF SHOWERS AND THUNDERSTORMS
AGAIN START TO INCREASE FROM WEST TO EAST ON SATURDAY. FRIES
&&
.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/...
BY SATURDAY NIGHT...OVERALL WIND FIELD/SHEAR VALUES WL BE ON THE
INCRS AS WEAKENING UPR TROF APPRCHES THE WRN LAKES. LATEST GFS AND
NAM SOLNS INDICATE OVRNGT SHRTWV/JET STREAK PROGRESSING ACRS THE
UPR OH REGION. GIVEN THE CONSISTENT NATURE OF THIS OVR THE PAST
CPL OF DAYS...HAVE UPPED PCPN PROBS TO THE LIKELY CATEGORY FOR
PASSAGE OF THE FEATURE. LATE NGT TIMING FAVORS DIMINISHED
INSTABILITY...HENCE SEVERE THREAT LKS MINIMAL.
CDFNT RMNS MDL-POISED FOR A SUNDAY PASSAGE AND LIKELY POPS WERE
HEDGED AND TAPERED OFF WITH TIMING DIFFERENCES RMNG IN TDAS SOLNS.
NEVERTHELESS...FRONTAL PASSAGE WL END THE PCPN POTENTIAL AND DRIVE
MONDAY TEMPS BACK TO...OR A FEW DEGREES BLO THE SEASONAL AVERAGES.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
MDLS ARE IN AGREEMENT IN DEPICTIONS OF A LOW AMPLITUDE MIDWEST
RIDGE AND ERN CONUS TROF FOR THE EARLY WEEK PTN. DRY WX IS THUS
FORECAST WITH COOL TEMPS.
AS THE WEEK PROGRESSES...A TEMP MODERATION CAN BE EXPECTED AS
DVLPG UPR MS VALLEY LOW INITIATES WARM ADVCTN OVR THE REGION. EWD
EVOLUTION OF THE LOW WL THEN HERALD AN INCRS IN POPS AS THE WEEK
DRAWS TO A CLOSE.
HPC NMBRS WERE REASONABLE FOR THE ENTIRE SCENARIO AND ONLY MINOR
ADJUSTMENTS WERE NEEDED TO THAT GUIDANCE.
&&
.AVIATION /01Z SATURDAY THROUGH WEDNESDAY/...
A WEAK UPPER LEVEL DISTURBANCE CURRENTLY CROSSING THE OHIO VALLEY
WILL BRING RAIN TO KZZV EARLY IN THE PERIOD...OTHERWISE...VFR
CONDITIONS WILL PERSIST TONIGHT AS WEAK HIGH PRESSURE SLOWLY
PUSHES TO THE EAST. ANOTHER UPPER LEVEL DISTURBANCE WILL MOVE OVER
THE REGION SATURDAY BUT CONFIDENCE NOT HIGH ENOUGH TO INTRODUCE TS
INTO TAFS. DID INTRODUCE GUSTS IN ALL SITES TOMORROW AFTERNOON AS
PRESSURE GRADIENT TIGHTENS WITH APPROACHING FRONT.
.OUTLOOK.../SATURDAY NIGHT THROUGH WEDNESDAY/...
BRIEF IFR RESTRICTIONS ARE LIKELY AHEAD AND ALONG A COLD FRONT
SATURDAY NIGHT INTO SUNDAY WITH RAIN. HIGH PRESSURE WILL RETURN
LATE SUNDAY NIGHT THROUGH WEDNESDAY...GIVING WAY TO VFR CONDITIONS.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
129 AM EDT THU MAY 30 2013
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 354 PM EDT WED MAY 29 2013
12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW RDG AXIS MOVING
INTO THE UPR GRT LKS DOWNSTREAM OF DEEPENING UPR TROF OVER THE
ROCKIES. ALTHOUGH SOME LO CLDS LINGER WITH LLVL MSTR SHOWN ON LOCAL
12Z RAOBS...COMBINATION OF SUBSIDENCE/LLVL ACYC FLOW ASSOCIATED WITH
RDG AXIS AND ARRIVAL OF VERY DRY AIR ABV THE SHALLOW MSTR AS SHOWN
ON THE 12Z MPX RAOB IS BRINGING DRY WX TO UPR MI. AT MID AFTN...THE
LO CLDS ARE FINALLY MIXING OUT FAIRLY STEADILY. FARTHER TO THE
SW...A PAIR OF SHRTWVS LIFTING NEWD OUT OF THE ROCKIES TROF ARE
BRINGING SOME SHRA/TS TO COME AREAS IN THE PLAINS...ESPECIALLY OVER
IOWA INTO SE MN AHEAD OF SFC-85 WARM FNT.
MAIN FCST CONCERNS TNGT INTO THU WL BE SHRA/TS CHCS ASSOCIATED WITH
RETURNING H85 WARM FNT AND SHRTWVS LIFTING NEWD OUT OF THE ROCKIES
TROF.
TNGT...MODELS ARE IN VERY GOOD AGREEMENT SHOWING CORE OF MID LVL DRY
AIR OVER THE CWA EARLY THIS EVNG UNDER UPR RDG AXIS SHIFTING TO THE
NE WITH APRCH OF WARM FNT TO THE SW. ALTHOUGH THE EARLY EVNG WL
LIKELY BE DRY...EXPECT INCRSG SHRA/TS CHCS BY 03Z WITH APRCH OF
SHRTWV NOW CAUSING SHRA/TS IN IOWA AS WELL AS AXIS OF HIER H85
DEWPTS AT NOSE OF STRENGTHENING H85 LLJ PUSHING KINX AT IWD TO 36 BY
06Z PER GFS FCST SDNGS. SINCE THE SHRTWV/MOISTENING ARE FCST TO
IMPACT MAINLY THE W HALF OF THE CWA...EXPECT THE HIER POPS IN THAT
AREA. IN FACT...THE ERN ZNS MAY REMAIN COMPLETELY DRY WITH KINX FCST
NO HIER THAN ABOUT 25 AT ERY THRU 12Z THU. FCST SDNGS INDICATE
STABILITY WL BE TOO MARGINAL FOR SVR STORMS...WITH SSI NO LOWER THAN
ABOUT -1C AND MUCAPE NO HIER THAN 300-350 J/KG WITH NARROW SKINNY
CAPE. EXPECT THE LOWEST MIN TEMPS OVER THE E CLOSER TO DEPARTING DRY
AIRMASS. AREAS OF FOG ARE LIKELY TO FORM IN THIS AREA UNDER THE MORE
PERSISTENT MID LVL DRY AIR.
THU...AS WARM FNT SHIFTS TO THE N ON THU...EXPECT BULK OF LINGERING
MRNG SHRA/TS OVER MAINLY THE W TO DIMINISH/END. QUESTION THEN
BECOMES WHETHER ADDITIONAL CONVECTION WL FIRE IN THE WARM SECTOR AFT
MRNG LO CLDS DSPT WITH DAYTIME HEATING/MIXING. THE BEST CHC FOR AFTN
SHRA/TS WL BE PROBABLY BE OVER THE W...UNDER LOWER HGTS CLOSER TO
CLOSED LO FCST TO DRIFT NWD THRU THE PLAINS. BUT EVEN THERE...GFS
FCST SDNGS HINT AT SUBSIDENCE INVRN IN THE H75-8 LYR THAT MIGHT
INHIBIT CONVECTION FOR AWHILE. IN FACT...BULK OF NUMERICAL GUIDANCE
SHOWS NO SHRA/TS DVLPG UNTIL 21Z...WHEN SFC TEMPS ARE LIKELY TO RISE
WELL INTO THE 80S UNDER H85 TEMPS IN THE 16-17C RANGE. MODIFIED GFS
FCST SDNG AT IWD FOR T/TD 85/60 YIELDS SBCAPE NEAR 1250 J/KG.
UNIDIRECTIONAL SSW FLOW AND SFC-6KM BULK SHEAR IN THE 20-30KT RANGE
AS WELL AS HI FRZG LVL/WBLB ZERO OF 13.7K FT/12.6K FT WOULD INDICATE
SVR THREAT IS FAIRLY SMALL. SINCE WARM FNT WL PROBABLY STALL OVER NW
LK SUP...PAINTED THE HIER POPS OVER THE KEWEENAW CLOSER TO THIS
BNDRY. SFC-6KM SHEAR IS FCST A BIT HIER IN THIS AREA AND UP TO 40
KTS...BUT LO CLDS SHOULD BE MORE PERSISTENT/STABILITY LOWER OVER THE
KEWEENAW.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 354 PM EDT WED MAY 29 2013
WARMER THAN NORMAL TEMPERATURES AND ACTIVE WEATHER EXPECTED THROUGH
THE END OF THE WORK WEEK AHEAD OF A LOW PRESSURE SYSTEM SHIFTING
EASTWARD FROM THE PLAINS. A COOLING TREND IS EXPECTED OVER THE
WEEKEND WITH NEAR NORMAL TEMPERATURES EXPECTED EARLY NEXT
WEEK...HOWEVER OVERNIGHT LOWS ARE EXPECTED TO BE QUITE COOL EARLY
NEXT WEEK WITH INLAND AREAS LIKELY REACHING THE LOW TO MID 30S.
THURSDAY NIGHT THROUGH SATURDAY...UPPER LEVEL 500MB CLOSED LOW AND
ASSOCIATED SURFACE LOW PRESSURE SYSTEM CENTERED OVER THE DAKOTAS
THURSDAY NIGHT WILL DRIFT SLOWLY EASTWARD INTO WESTERN MN BY
THURSDAY NIGHT. THIS WILL KEEP UPPER MI IN WARM MOIST SOUTHERLY
FLOW. THE BETTER MOISTURE TRANSPORT INTO THE REGION IS PROGGED TO
OCCUR THURSDAY NIGHT THROUGH EARLY FRIDAY MORNING...AS PRESSURE
GRADIENT IS INCREASED BETWEEN THE TROUGH TO THE WEST AND RIDGE TO
THE EAST. UPPER MI IS ON THE NORTHERN FRINGES OF THIS PRESSURE
GRADIENT...DIFFLUENT REGION...ALLOWING WIND SPEEDS TO DECREASE OVER
UPPER MI. AS A RESULT...850MB CONVERGENCE IS ENHANCED OVER NORTHERN
WI AND UPPER MI PROVIDING ENOUGH FORCING TO INCREASE THE CHANCE OF
SHOWERS AND THUNDERSTORMS ACROSS THE REGION. MUCAPE VALUES ARE
PROGGED TO BE AROUND 500-600 J/KG WHICH MAY BE ENHANCED A BIT AS
500MB SHORTWAVE ROTATES THROUGH THE REGION THURSDAY NIGHT. THE
SURFACE LOW AND UPPER LEVEL LOW WILL THEN SHIFT FROM WESTERN MN
FRIDAY MORNING INTO WI AND UPPER MI BY SATURDAY AFTERNOON. DURING
THIS TIME PERIOD THE BETTER CHANCES FOR PRECIPITATION WILL SHIFT
EASTWARD...REMAINING OVER MAINLY EASTERN UPPER MI AND MOST OF LOWER
MI AS THE PRESSURE GRADIENT AND AFOREMENTIONED CONVERGENCE ALSO
SHIFTS EASTWARD. ENOUGH MOISTURE WILL REMAIN IN PLACE OVER MUCH OF
UPPER MI ALONG WITH COOLER AIR MOVING IN THROUGH THE DAY
SATURDAY...TO KEEP THE CHANCE OF SHOWERS AND THUNDERSTORMS IN THE
FORECAST.
SATURDAY NIGHT THROUGH SUNDAY...THE LOW PRESSURE SYSTEM OVER UPPER
MI SATURDAY NIGHT IS EXPECTED TO CONTINUE TO TREK EASTWARD SHIFTING
TO SOUTHERN ONTARIO AND SOUTHERN QUEBEC THROUGH SUNDAY AFTERNOON. AS
THIS HAPPENS...UPPER MI WILL BE PLACED ON THE BACK SIDE OF THE LOW
PRESSURE SYSTEM ALLOWING COOLER AIR TO PUSH INTO THE AREA. ENOUGH
WRAP AROUND MOISTURE WILL LINGER THROUGH SUNDAY AFTERNOON AND
EVENING TO KEEP INCREASED CLOUD COVER OVER THE REGION ALONG WITH THE
CHANCE OF SHOWERS. WHEN PLOTTING 1000-500MB OMEGA ON PLAN VIEW AND
CROSS SECTIONS...INCREASED RH VALUES AND FORCING ARE COLLOCATED OVER
MUCH OF THE UPPER PENINSULA THROUGH SUNDAY AFTERNOON. AS WAS THE
CASE OVER THE LAST FEW SHIFTS...THE GFS TRIES TO PULL DRY AIR INTO
THE REGION MUCH FASTER THAN THE EC/GEM...THEREFORE...WILL KEEP
INCREASED CLOUD COVER IN THE FORECAST INTO THE LATE AFTERNOON INTO
EARLY SUNDAY EVENING. THE GFS WOULD HAVE ALL CLOUD COVER OUT OF THE
AREA BETWEEN 12 AND 18Z SUNDAY.
SUNDAY NIGHT THROUGH WEDNESDAY...IN THE WAKE OF THE UPPER LEVEL
500MB LOW AND SURFACE LOW...EXPECT AN UPPER LEVEL 500MB RIDGE AND
SURFACE HIGH TO BUILD EASTWARD FROM THE PLAINS SUNDAY NIGHT REACHING
THE UPPER GREAT LAKES REGION BY LATE MONDAY MORNING. THE RIDGE WILL
REMAIN IN PLACE THROUGH TUESDAY EVENING...KEEPING CONDITIONS DRY AND
SKIES MOSTLY SUNNY. SUNDAY NIGHT INTO MONDAY NIGHT...OVERNIGHT LOWS
AREA EXPECTED TO BE FAIRLY COLD FOR THIS TIME OF YEAR AS 850MB TEMPS
AREA EXPECTED TO DROP TO AROUND 0C TO 2C. THIS COUPLED WITH CALM
WINDS...CLEAR SKIES AND DRY AIR...WILL ALLOW FOR MAXIMUM RADIATIONAL
COOLING. AREAS INLAND WEST COULD FALL TO NEAR FREEZING SUNDAY NIGHT
WHILE THE INLAND EAST AREAS COULD SEE NEAR FREEZING TEMPERATURES
MONDAY NIGHT AS THE HIGH PRESSURE CENTER SHIFTS EASTWARD. THE NEXT
AREA OF LOW PRESSURE DEVELOPING OVER SOUTHERN CANADA AND THE
NORTHERN ROCKIES MONDAY AFTERNOON WILL SHIFT SLOWLY EASTWARD
REACHING WESTERN UPPER MI BY LATE TUESDAY NIGHT INTO WEDNESDAY
MORNING. SIGNIFICANT TIMING AND SYSTEM INTENSITY DIFFERENCES EXIST
FROM MODEL TO MODEL AND FROM MODEL RUN TO MODEL RUN CAUSING A BELOW
AVERAGE CONFIDENCE LEVEL IN THE FORECAST FOR WEDNESDAY...THEREFORE
HAVE DECIDED TO LEAN TOWARD A CONSENSUS OF THE MODELS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 129 AM EDT THU MAY 30 2013
A DISTURBANCE MOVING IN WL BRING THE THREAT OF SOME SHRA AND
POSSIBLY A TS TO MAINLY IWD AND CMX OVERNIGHT. VFR CONDITIONS WILL
CONTINUE THROUGH THE PERIOD AT IWD...BUT AT CMX WHEN THE SHOWERS
MOVE THROUGH...COULD TEMPORARILY SEE MVFR CIGS/VIS OVERNIGHT. AT
SAW...SIGNS ARE POINTING TO AN UPSLOPE FOG EVENT FROM LOW LEVEL
MOISTURE COMING IN FROM LAKE MICHIGAN. EARLIER THINKING WAS SOME LOW
CLOUDS WOULD FORM...BUT ESC DEW POINT HAS REALLY DROPPED AND THINK
FOG WILL BE THE MAIN THREAT NOW. WILL GO MVFR VIS OVERNIGHT AT SAW
WITH SOUTH UPSLOPE WINDS. MIXING AND HEATING WILL BRING BACK VFR BY
MID MORNING AT SAW. COULD SEE SAME THING HAPPEN AT SAW MID THU
EVENING.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 354 PM EDT WED MAY 29 2013
WITH GENERALLY WEAK PRES GRADIENT AND STABLE CONDITIONS OVER LAKE
SUPERIOR...EXPECT WINDS TO BE UNDER 25KT THRU THE WEEK. WIDESPREAD
FOG IS LIKELY...ESPECIALLY AFTER RAINFALL OCCURS OVER THE LAKE. AT
LEAST PATCHY DENSE FOG IS LIKELY INTO SAT. HIGH PRESSURE WILL MOVE
INTO THE AREA SUNDAY NIGHT AND REMAIN OVERHEAD THROUGH LATE TUESDAY
NIGHT...KEEPING WINDS VARIABLE AND LESS THAN 25 KNOTS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...KEC
AVIATION...07
MARINE...KEC
AREA FORECAST DISCUSSION
NWS GAYLORD MI
100 AM EDT THU MAY 30 2013
.SYNOPSIS...
ISSUED AT 432 PM EDT WED MAY 29 2013
UNSETTLED WEATHER WILL BE THE RULE THROUGH THE NEAR FUTURE...AS A
WARM FRONT GRADUALLY LIFTS NORTH INTO ONTARIO BY THURSDAY. THIS
FEATURE WILL PROVIDE CHANCES FOR SCATTERED SHOWERS AND THUNDERSTORMS
THROUGH MID DAY ON THURSDAY. WE`LL GET A BREAK FROM THE ACTIVITY FOR
THURSDAY AFTERNOON AND EVENING. BUT MORE CHANCES FOR SHOWERS AND
STORMS WILL ENTER THE PICTURE FRIDAY THROUGH SUNDAY...AS A COLD
FRONT SLOWLY SLIDES ACROSS THE GREAT LAKES.
&&
.UPDATE...
ISSUED AT 1259 AM EDT THU MAY 30 2013
03Z MESOANALYSIS SHOWS BROAD POOL OF THUNDERSTORM-COOLED AIR ACROSS
MUCH OF WESTERN/CENTRAL WISCONSIN/NORTHEAST IOWA WITH THE LEADING
EDGE OUTFLOW BOUNDARY ARCING ACROSS EASTERN WISCONSIN BACK INTO EAST
CENTRAL IOWA. TEMPERATURES WERE IN THE 60S ACROSS A GOOD CHUNK OF
NORTHERN LOWER...WITH DEW POINT TEMPERATURES NOT TOO DISSIMILAR.
SKIES WERE MAINLY CLEAR ACROSS NORTHERN LOWER...WITH LOW CLOUDS
ACROSS UPPER MICHIGAN AND JUST GRAZING THE NORTHEAST LOWER SHORELINE
FROM LAKE HURON. GETTING SOME PATCHY FOG DEVELOPMENT AS WELL.
LARGE AREA OF SHOWERS/THUNDERSTORMS ACROSS WISCONSIN SPREADING INTO
WESTERN UPPER MICHIGAN...LEADING EDGE CONVECTION ALONG OUTFLOW
BOUNDARY HAS BEEN WEAKENING AS IT APPROACHES THE WISCONSIN
SHORELINE. 00Z APX SOUNDING SHOWED A FAIRLY SHALLOW MIXED LAYER
CAPPED BY A SUBSIDENCE INVERSION IN THE 860-850MB LAYER. THERE IS A
LOW LEVEL THETA-E RIDGE THAT RUNS FROM FKS-MBL SOUTHEAST TOWARD
GRR-LAN-PTK WHERE THERE IS SOME POTENTIAL INSTABILITY THOUGH IT MAY
BE TOO DRY/CAPPED TO SUPPORT CONVECTIVE DEVELOPMENT. WILL KEEP AN
EYE ON THIS AREA TO MAKE SURE NO MISCHIEF DEVELOPS. OTHERWISE...
WILL MAKE A FEW ADJUSTMENTS TO POP GRIDS AS WELL AS FOG TO COVER
MARINE LAYER INTRUSION INTO FAR NORTHEAST LOWER.
UPDATE ISSUED AT 1019 PM EDT WED MAY 29 2013
CLEAR CONCERNS FOR THE OVERNIGHT ARE FOG AND PRECIP.
AIR MASS OVER MOST OF NORTHERN MI IS PRIMED FOR FOG. MARINE LAYER
HAS COME CHARGING IN FROM LAKE HURON...WITH THE OSC AWOS/SPOTTERS/
FOG IMAGERY SHOWING FOG IN THAT AREA...ALMOST UP TO APN. PLENTY OF
MARINE AIR STILL IN PLACE FROM THE STRAITS NORTH AS WELL.
MEANWHILE...RADIATIONAL COOLING BARELY UNDERWAY...BUT IS ALREADY
REDUCING VSBYS AT PLN AND BELLAIRE. WE HAD GROUND FOG DEVELOPING
IN A FIELD ADJOINING THE OFFICE RIGHT AT SUNSET. OF COURSE...
FAVORABLE RADIATIONAL COOLING CONDITIONS WILL BE COMING TO AN END
SOON...AS A THICK CIRRUS SHROUD IS ADVANCING ABOVE LAKE MI AND
CENTRAL UPPER MI. THIS SHOULD KEEP WIDESPREAD PEA SOUP FROM
FORMING...BUT HAVE STEADILY EXPANDED FOG MENTION AND SEVERITY IN
THE GRIDDED FORECASTS.
HAVE ALSO REJIGGERED PRECIP CHANCES. RADAR TRENDS IN WI REMAIN
SOMEWHAT OMINOUS AT 1ST GLANCE. BUT THE 00Z SOUNDING FROM GRB IS
RELATIVELY DRY (PWAT 0.9) AND CAPPED...AND THAT AIR MASS ISN/T
GETTING MORE UNSTABLE WITH TIME. 00Z APX SOUNDING WAS LESS
UNSTABLE AND MORE CAPPED. THOUGH A WARMER/MORE MOIST AIR MASS WILL
TRY TO WORK NORTHWARD INTO NORTHERN MI...THE LOW LEVEL JET WILL BE
MUCH STRONGER TO OUR WEST. UPSTREAM MCS APPEARS TO BE EVOLVING IN
RESPONSE...WITH LIGHTNING BECOMING LESS COMMON ALONG IT/S LEADING
(EASTERN) EDGE...AND MORE COMMON ALONG THE RIGHT REAR (SOUTHWEST)
FLANK. THUS...THE EARLIER FORECAST THINKING STILL APPEARS
SOUND....LIFTING THE MCS REMNANTS NE-WARD ACROSS WI AND UPPER MI
OVERNIGHT. LATEST HRRR RUNS REMAIN SUPPORTIVE OF THIS
THINKING...WITH NO PRECIP IN THIS CWA EXCEPT IN FAR WESTERN
CHIP/MACK. HAVE REMOVED CHANCE POPS FROM NE LOWER...ADDED SMALL
CHANCE POPS ALONG THE NW LOWER MI COAST...AND RETAINED CHANCE POPS
IN EASTERN UPPER (HIGHEST IN WESTERN CHIP/MACK).
MIN TEMPS WILL BE QUITE MILD OUTSIDE OF MARINE-INFLUENCED AREAS.
UPDATE ISSUED AT 739 PM EDT WED MAY 29 2013
APPEARS TO BE SAFE TO PULL PRECIP FROM THE SAGINAW BAY REGION THIS
EVENING. CU FIELD IS IN DECLINE...AND EARLIER ECHOES ON RADAR HAVE
EXITED.
HAVE REDUCED CLOUD COVER SUBSTANTIALLY THIS EVENING...PER SAT
TRENDS...ESPECIALLY IN NORTHERN LOWER MI.
HAVE EXPANDED FOG INTO PARTS OF NORTHERN LOWER...ESPECIALLY WHERE
LOW CLOUDS AND/OR MARINE AIR LINGERED LONGEST TODAY. TEMP/DEW
POINT SPREADS ARE ALREADY 10F OR LESS AT APN/PLN...AND WITH WINDS
LIGHTENING AND SKIES (TEMPORARILY) CLEARING...CERTAINLY LOOKS LIKE
SOME FOG COULD FORM QUITE QUICKLY...PERHAPS EVEN BY MIDNIGHT. IT
WILL BE AN INTERESTING RACE...AS A CIRRUS SHROUD FROM UPSTREAM
SHRA/TSRA IS STEADILY ADVANCING ACROSS WI...AND WILL BE
ENCROACHING ON THE AREA LATE EVENING AND ESPECIALLY OVERNIGHT.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 432 PM EDT WED MAY 29 2013
ON THE LATEST SURFACE WEATHER MAP...1022 MB HIGH PRESSURE WAS OVER
VIRGINIA WHILE 1003 MB LOW PRESSURE WAS OVER NORTHERN ONTARIO AND
992 MB LOW PRESSURE WAS OVER WESTERN KANSAS...WHILE A SURFACE WARM
FRONT WAS LOCATED JUST SOUTH OF THE FORECAST AREA. SATELLITE
IMAGERY SHOWED LOTS OF CLOUDS ACROSS NORTHERN MICHIGAN BUT APX
RADAR WAS VOID OF RETURNS. THE MAIN SHORT TERM FORECAST CONCERNS
ARE NUMEROUS AND INCLUDE THUNDERSTORM POTENTIAL ACROSS SOUTHEAST
ZONES INTO THE EVENING HOURS THEN THUNDERSTORM CHANCES OVERNIGHT
AND AGAIN THURSDAY ACROSS ALL OF THE COUNTY WARNING AREA.
THIS EVENING...CLOUDS HAVE BEEN A REAL CHALLENGE THIS AFTERNOON AS
USUAL. MARINE STRATUS CONTINUES TO PLAGUE MARINE AREAS...AS WELL AS
SPILLING INTO NORTHWEST LOWER WHILE SOUTHWEST ZONES HAVE SEEN AN
INCREASE IN DIURNALLY DRIVEN CU (AFTER THE LOW CLOUDS MIXED OUT
EARLIER). THE TREND HAS BEEN FOR CLOUDS TO GENERALLY DISSIPATE
ACROSS THE SOUTHWESTERN ZONES AND THIS SHOULD CONTINUE THROUGH THE
EVENING HOURS. COULD SEE A SHOWER OR THUNDERSTORM POP UP ACROSS
SOUTHEAST ZONES OVER THE NEXT FEW HOURS WHERE THERE WAS THE MOST
SUN/HEATING TODAY...IN COMBINATION WITH A BIT OF CONVERGENCE FROM A
LAKE BREEZE OFF OF LAKE HURON. THEREFORE...WILL CONTINUE WITH LOW
CHANCE POPS DOWN THERE. SEVERE POTENTIAL LOOKS LIMITED WITH WINDS
ALOFT ON THE LIGHT SIDE.
OVERNIGHT...CONVECTION ACROSS EASTERN MINNESOTA AND EASTERN IOWA
EXPECTED TO TRACK TOWARD THE THETA-E RIDGE MOVING INTO THE NORTHERN
HALF OF THE FORECAST AREA OVERNIGHT. STILL SOME DOUBT WHETHER THESE
STORMS WILL SURVIVE THIS FAR EAST...SO WILL CONTINUE TO COVER IT
WITH CHANCE WORDING. SEVERE POTENTIAL REMAINS LIMITED WITH 0-6KM
BULK SHEAR OF 30 KNOTS OR LESS. WARM AND MUGGY OVERNIGHT WITH
LOWS RANGING FROM THE MIDDLE 50S NORTH TO THE MIDDLE 60S SOUTH.
THURSDAY...WE ARE EXPECTED TO FINALLY BREAK OUT INTO THE WARM
SECTOR AS THE SURFACE WARM FRONT MOVES THROUGH THE REGION LEADING
TO HIGHS RANGING FROM THE UPPER 70S NORTH TO THE MIDDLE 80S
SOUTHEAST. IN ADDITION...THETA-E RIDGE BUILDS IN FROM THE WEST. LOOKING
AT MODEL SOUNDINGS...NOT MUCH CAPPING IN EVIDENCE SO COULD SEE A
FEW INSTABILITY DRIVEN THUNDERSTORMS DEVELOPING IN THE AFTERNOON
AND EARLY EVENING HOURS...SO HAVE ADDED IN LOW CHANCE POPS.
&&
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 432 PM EDT WED MAY 29 2013
OVERVIEW: 4-WAVE HEMISPHERIC PATTERN IN PLACE TO START THIS FORECAST
CYCLE WITH LONG WAVE TROUGHS ANCHORED OVER THE EASTERN PACIFIC (NEAR
150W) AS WELL AS FAR EASTERN CANADA (NEAR 60W)...WITH LOW AMPLITUDE
RIDGING IN BETWEEN. ON THE SHORTER SCALE...FAST MID LEVEL FLOW IN
PLACE ACROSS THE EASTERN PACIFIC DIGGING INTO AN INVERTED SHORT WAVE
TROUGH IN THE WESTERN CONUS INTO THE PLAINS. ASSOCIATED SFC LOW
CENTERED NEAR THE COLORADO/KANSAS BORDER THIS MORNING WITH A
SOMEWHAT STATIONARY FRONT ARCHING UP INTO THE GREAT LAKES. SFC LOW
AND STATIONARY FRONT CONTINUE TO DRIVE EPISODES OF SHOWERS AND
STORMS FROM THE CENTRAL PLAINS THROUGH THE MIDWEST/LOWER GREAT
LAKES. SHORT WAVE TROUGH WILL CONTINUE TO BE THE MAIN WEATHER PLAYER
AS IT SLOWLY WORKS THROUGH THE PLAINS AND ULTIMATELY THE GREAT LAKES
OVER THE NEXT SEVERAL DAYS. CONVECTIVE TRENDS/TIMING WILL BE THE
TOUGH PART OF THE FORECAST AS THIS OCCURS. TEMPERATURES WILL
INITIALLY BE ON THE WARMER SIDE OF THINGS (RAIN AND CLOUDS
DEPENDENT) BUT TURN RATHER COOL AGAIN FOR THE WEEKEND AS THE TROUGH
AND ASSOCIATED POCKET OF COLD AIR WORK THROUGH. SHAPING UP TO BE
ANOTHER RIP-OFF SUMMER WEEKEND...SORRY.
THURSDAY NIGHT AND FRIDAY...CLOSED AND NEARLY STACKED LOW PRESSURE
SYSTEM EXPECTED TO BE MIGRATING SLOWLY ACROSS THE NRN PLAINS INTO
THE UPPER MIDWEST THROUGH THIS TIMEFRAME WITH THE FRONT STRETCHED
SOMEWHERE THROUGH THE NRN GREAT LAKES. MAIN FOCUS FOR CONVECTION
THURSDAY NIGHT WILL LIKELY BE ACROSS THE MID TO UPPER MISSISSIPPI
RIVER VALLEY WHERE WARM/MOIST SOUTHERLY INFLOW WILL INTERACT WITH
BETTER SYNOPTIC FORCING. BUT THERE WILL BE THE CHANCE THAT SOME OF
THAT ACTIVITY COULD EVENTUALLY SPREAD INTO THE GREAT LAKES THURSDAY
NIGHT/FRIDAY MORNING AS MID LEVEL SHORT WAVE IMPULSE SWINGS UP INTO
THE REGION. THAT SAID...TOUGH TO HAVE HIGH CONFIDENCE IN THE DETAILS
AT THIS JUNCTURE GIVEN ALL THE CONVECTION THAT WILL OCCUR BETWEEN
NOW AND THEN. SO FOR NOW WILL HAVE JUST CHANCY POPS OVERNIGHT
THURSDAY NIGHT OVER THE WESTERN HALF OF THE CWA...AND ACROSS THE CWA
ON FRIDAY. DETAILS WILL HAVE TO BE REFINED LATER.
FRIDAY NIGHT THROUGH SUNDAY...PATTERN REMAINS UNSETTLED RIGHT ON
THROUGH THE WEEKEND AS PESKY CLOSED LOW MAKES SLOW PROGRESS INTO THE
GREAT LAKES. SHOWERS AND STORMS APPEAR MOST LIKELY ACROSS THE GREAT
LAKES REGION FRIDAY NIGHT INTO SATURDAY AS THE ASSOCIATED SFC FRONT
AND UPPER JET CORE PRESS INTO THE GREAT LAKES REGION...AND WILL HAVE
HIGHEST POPS DURING THIS TIME. AFTER FROPA...SUNDAY SHAPING UP TO BE
COOL AND DAMP ONCE AGAIN AS LIGHTER PRECIP LINGERS AND TEMPS DIP
BACK BELOW NORMAL.
MONDAY THROUGH WEDNESDAY...MID LEVEL TROUGH AND CORE OF COLD AIR
SLOWLY RETREATS EASTWARD ON MONDAY FOLLOWED BY LOWER AMPLITUDE
RIDGING FOR TUESDAY INTO WEDNESDAY. LARGE EXPANSE OF CANADIAN HIGH
PRESSURE SETTLES IN FOR MONDAY AND TUESDAY WHICH WILL CLEAR THINGS
OUT AND MAY LEAD MORE FROST POTENTIAL BOTH MONDAY AND TUESDAY
MORNING. DAYTIME TEMPS REBOUND FOR TUESDAY AND WEDNESDAY BACK CLOSE
TO NORMAL. HOWEVER...YET ANOTHER TROUGH IS SLATED TO BE DIPPING INTO
THE UPPER MIDWEST/WESTERN GREAT LAKES AROUND MIDWEEK BRINGING
ADDITIONAL RAIN CHANCES TO THE REGION TO ROUND OUT THE EXTENDED
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1258 AM EDT THU MAY 30 2013
FOG OVERNIGHT AT APN/PLN. SMALL CHANCES FOR SHRA/TSRA THURSDAY
AFTERNOON/EARLY EVENING.
A WEAK RIDGE OF HIGH PRESSURE HAS SHIFTED EAST TO THE EASTERN GREAT
LAKES. THAT WILL ALLOW WARM/MOIST SOUTHERLY FLOW TO RETURN TO THE
REGION THURSDAY. MARINE FOG/STRATUS HAS RETURNED TO APN WITH A LIGHT
SE WIND OFF OF HURON...WHILE PLN HAS SEEN OLD FASHIONED RADIATIONAL
FOG FORM. BOTH SITES ARE EXPECTED TO BE LIFR FOR THE BULK OF THE
OVERNIGHT...THOUGH SOME SLIGHT IMPROVEMENT MAY OCCUR AS CIRRUS
INCREASES OVERHEAD AND SLOWS THE COOLING PROCESS DOWN LOW. TVC/MBL
WILL SEE MUCH LESS IN THE WAY OF FOG...THOUGH COULD DIP INTO MVFR
TERRITORY AT TIMES. CONDITIONS WILL IMPROVE TO VFR AT ALL SITES
THURSDAY MORNING.
A CU FIELD WILL DEVELOP THURSDAY IN A WARM/MUGGY AIR MASS. SOME
SHRA/TSRA WILL TRY TO GET GOING IN THE AFTERNOON. THE BEST CHANCE
FOR THIS WILL BE INLAND FROM LAKE MI...AND WILL HAVE VCSH MENTIONED
ONLY AT PLN/APN IN THE AFTERNOON.
LIGHT WINDS OVERNIGHT. SOUTH WINDS THURSDAY...BREEZIEST AT MBL.
&&
.MARINE...
ISSUED AT 432 PM EDT WED MAY 29 2013
WINDS NOT EXPECTED TO BE MUCH OF AN ISSUE THROUGH TONIGHT...GENERAL
SOUTHWEST GRADIENT WIND WITH SOME LAKE BREEZE INFLUENCE ON WHITEFISH
BAY AND FAR NORTHERN LAKE HURON NEARSHORE ZONES. WINDS WILL BECOME
MORE SOUTHERLY TONIGHT. REDUCED VISIBILITIES IN AREAS OF FOG AND
HAZE WILL BE AN ISSUE THROUGH THURSDAY GIVEN RELATIVELY HUMID AIR
MASS IN PLACE INTERACTING WITH COLDER LAKE WATERS. SOUTHERLY WINDS
WILL INCREASE BY FRIDAY AFTERNOON...WITH SMALL CRAFT ADVISORIES
LIKELY NEEDED ACROSS A MAJORITY OF THE NEARSHORE ZONES.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...NONE.
LM...NONE.
LS...NONE.
&&
$$
UPDATE...JPB
SYNOPSIS...KAB
SHORT TERM...AJS
LONG TERM...TBA
AVIATION...JZ
MARINE...AJS
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
1249 PM CDT THU MAY 30 2013
.UPDATE...
FOR 18Z AVIATION DISCUSSION BELOW.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 353 AM CDT THU MAY 30 2013
A VERY ACTIVE SHORT TERM IS IN STORE AS A POTENT UPPER WAVE WORKS
ACROSS THE NATIONS MIDSECTION. H5 RAP ANALYSIS SHOWS A CLOSED LOW
HAS DEVELOPED NEAR THE BLACK HILLS THIS MORNING...WITH A NEGATIVELY
TITLED TROUGH EXTENDING FROM THERE DOWN TO NORTHEAST TEXAS. THE
RADAR MOSAIC WEDNESDAY WAS CRAMMED FULL OF CONVECTION FROM HERE ALL
THE WAY DOWN TO TEXAS...WHICH MEANS WITHIN THIS LARGE SCALE TROUGH
THERE ARE NUMEROUS LEFT OVER WAVES/MCVS. ONE SUCH WAVE IS OVER SW IA
THAT WILL SWING THROUGH HERE IN THE LATE MORNING. THE MAIN SYNOPTIC
UPPER WAVE WILL BEGIN WORKING ACROSS MN THIS AFTERNOON AND EVENING.
TO GO ALONG WITH ALL OF THE WAVES...A 50 KT LLJ IS CURRENTLY BLOWING
ACROSS MN. THIS LLJ WILL SLOWLY DIMINISH THROUGH THE MORNING...BUT A
MUCH STRONGER PUSH CURRENTLY OVER OK/KS WILL COME UP INTO SE MN/WRN
WI THIS AFTERNOON/EVENING WITH THE PRIMARY SYNOPTIC WAVE.
AT THE SFC...A 995 MB SFC LOW CAN BE FOUND NEAR PIERRE SOUTH
DAKOTA...WITH A WARM FRONT SITTING ACROSS CENTRAL MN. DURING THE
SHORT TERM...THIS LOW WILL BECOME OCCLUDED AND SLOWLY MEANDER NORTH
INTO NODAK. THE WARM FRONT WILL CONTINUE TO MOVE NORTH
TODAY...EVENTUALLY SETTLING ALONG THE INTERNATIONAL BORDER. BACK TO
THE WEST...A COLD FRONT MOVING ACROSS SODAK TODAY WILL BE ENTERING
WRN MN BY THE END OF THE PERIOD.
FOR TODAY...EXPECT A BRIEF LULL IN ACTIVITY THIS MORNING AS WE WAIT
FOR THE WAVE OVER SW IA TO GET HERE AROUND 15Z. FORECAST SOUNDINGS
ACROSS THE ENTIRE CWA SHOW VERY LITTLE IF ANY CAPPING...SO EXPECT
SHOWERS AND STORMS TO DEVELOP QUICKLY THIS MORNING ONCE A LITTLE
DAYTIME HEATING KICKS IN. SINCE WE WILL NOT BE ABLE TO BUILD MUCH
INSTABILITY THANKS TO DENSE CLOUD COVER AND THE FACT THAT ONCE A
LITTLE DEVELOPS THE ATMO WILL QUICKLY CONSUME IT...THE SEVERE THREAT
LOOKS FAIRLY LOW TODAY. FOR SEVERE WEATHER...WILL HAVE TO WATCH THAT
SECOND LLJ WORKING UP IN THE AFTERNOON. BY 00Z THE RAP HAS 50 KT
WINDS AT H85 UP INTO OUR WI CWA. LIKE YESTERDAY...THIS COULD LEAD TO
THE THREAT FOR BOWING LINE SEGMENTS AND DAMAGING WINDS.
AS FOR ANY HYDROLOGY ISSUES TODAY...THE ONLY AREA THAT WILL
PROBABLY HAVE TO BE WATCHED IS THE EAU CLAIRE AREA. THEY SET A DAILY
RAINFALL RECORD YESTERDAY AND WILL BE UNDER THE GUN FOR THE SECOND
LLJ SURGE THIS AFTERNOON...WITH THE POTENTIAL FOR SOME TRAINING OF
STORMS THIS AFTERNOON AND EVENING.
TONIGHT...THE COLD FRONT WILL START ENTERING WRN MN WHILE THE LLJ
WORKS INTO CENTRAL/ERN WI. THIS SHOULD MOVE THE HEAVY RAIN THREAT
EAST OF THE MPX CWA TONIGHT. HOWEVER...HI-RES CAMS SHOW SCT RETURNS
CONTINUING THROUGH THE NIGHT AHEAD OF THE FRONT...SO HAVE POPS
SLOWLY RAMPING DOWN FROM LIKELIES TO START THE EVENING...DOWN TO 50%
POPS OR LESS BY 12Z FRIDAY.
FOR TEMPERATURES...GIVEN ALL OF THE CLOUD COVER...IT WILL NOT BE AN
OVERLY WARM WARM SECTOR TODAY...WITH HIGHS LIKELY STAYING IN THE MID
TO UPPER 70S...DESPITE H85 TEMPS BEING UP AROUND +15C. FOR
TONIGHT...MIXED LAYER DEWPS ON THE NAM DROP INTO THE 40S BEHIND THE
FRONT...SO LOWS IN THE WRN CWA COULD END UP BEING A FEW DEGREES
COOLER THAN WHAT IS CURRENTLY INDICATED.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 353 AM CDT THU MAY 30 2013
MODELS INDICATE RATHER STRONG TROUGH AXIS WORKING THROUGH THE
AREA BY FRIDAY MORNING. THIS SHOULD WORK MUCH OF THE RAIN AND
THUNDER TO THE NORTH AND EAST OF THE AREA LATE THURSDAY NIGHT.
THIS SHOULD WORK A DRY SLOT NORTHEAST INTO SOUTHWEST PORTION OF
THE CWA DURING FRIDAY MORNING. THE UPPER CIRCULATION THEN MOVES A
FRONTAL BOUNDARY EAST ACROSS EASTERN HALF OF THE CWA FRIDAY
AFTERNOON. THE DETERMINISTIC MODELS ARE INDICATING MODEST
DESTABILIZATION ACROSS THE EASTERN HALF OF THE AREA...WITH ML
MUCAPE INCREASING TO 1500/2000 J/KG. SHEAR INCREASES INTO THE
AFTERNOON...ESPECIALLY INTO WESTERN WISCONSIN. THE ONLY INHIBITING
FACTOR FOR CONVECTIVE INITIATION ALONG THE FRONT APPEARS TO BE
RATHER WEAK SURFACE CONVERGENCE..WITH WINDS S-SW ALONG THE
BOUNDARY. THE HIRES MODELS ARE SHOWING RATHER ROBUST CONVECTION
DEVELOPING ALONG THE BOUNDARY AS IT MOVES INTO EASTERN MINNESOTA
FRIDAY AFTERNOON. WILL HAVE TO MONITOR THIS SITUATION INTO
FRIDAY...AS SEVERE WEATHER THREAT IS FORECAST TO BE LOW AT THIS
TIME.
FRONT EXITS TO THE EAST FRIDAY NIGHT TAKING THE HEAVY CONVECTIVE
POTENTIAL WITH IT. THIS WILL LEAVE THE UPPER LOW OVER THE AREA
THROUGH AT LEAST SATURDAY. SHOWERS LOOK TO BE A FAIR BET
ESPECIALLY LATER IN THE DAY AS THE LOW MOVES EAST. WITH ABUNDANT
CLOUD COVER...WILL BE LITTLE IN THE WAY OF HEATING...SO CONVECTIVE
POTENTIAL IS LOW. CLEARING SHOULD MOVE INTO THE AREA LATER
SATURDAY NIGHT...AND SUNDAY LOOKS LIKE THE BEST DAY OF THE
WEEKEND...WITH SUNSHINE AND MILD TEMPERATURES.
THE EXTENDED PORTION OF THE FORECAST STARTS OFF RATHER
COOL...ESPECIALLY OVER THE EASTERN CWA MONDAY MORNING. THERE MAY
EVEN BE A FROST POTENTIAL OVER A PORTION OF WEST CENTRAL
WISCONSIN. THE NEXT WEATHER SYSTEM MOVES INTO THE AREA LATER
MONDAY WITH SOME SHOWERS INTO THE WESTERN CWA. THE 00Z GFS AND
ECMWF DIVERGE SOMEWHAT ON THE OVERALL EVOLUTION AND MOVEMENT OF
THE NEXT LOW PRESSURE SYSTEM THAT MOVES ACROSS THE NORTHERN STATES
THROUGH MUCH OF NEXT WEEK. IT DOES APPEAR THE THREAT OF MORE
SHOWERS AND THUNDERSTORMS RETURNS BY MIDWEEK...WITH TEMPERATURES
REMAINING BELOW NORMAL THROUGH THE PERIOD.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1248 PM CDT THU MAY 30 2013
SCATTERED SHOWERS AND THUNDERSTORMS...POSSIBLY STRONG...WILL
PLAGUE THE WI TAF SITES THIS AFTERNOON AND EARLY EVENING...WITH
WIDELY SCATTERED NON-SEVERE ACTIVITY TO THE WEST OVER MN. CIGS
WILL REMAIN BETWEEN 2500-3500 FT THROUGHOUT...WITH THE POTENTIAL
FOR IFR VSBYS ATTENDANT WITH ANY SHOWERS/TS THAT AFFECT SITES.
WINDS WILL GUST TO BETWEEN 25 AND 30 KTS THIS AFTERNOON...AND
AGAIN ON FRIDAY. SHOWERS AND ISOLATED THUNDERSTORMS WILL BE
POSSIBLE AGAIN ON FRIDAY...BUT TIMING/COVERAGE CONFIDENCE IS TOO
LOW TO INCLUDE IN THE TAF AT THIS POINT.
KMSP...
SCT-BKN CLOUDS BETWEEN 2500-3500 FT WILL PREVAIL THROUGH THIS
EVENING. THE MAIN WINDOW FOR SHOWERS AND POSSIBLY ISOLATED THUNDER
WILL BE BETWEEN 23Z AND 04Z...THEN A BREAK IS EXPECTED BEFORE
DIURNALLY DRIVEN ACTIVITY POSSIBLY DEVELOPS AGAIN ON FRIDAY.
SOUTHERLY WINDS WILL GUST INTO THE UPPER 20S /KNOTS/ THIS
AFTERNOON...THEN BECOME GUSTY AGAIN BY 15Z FRIDAY.
/OUTLOOK FOR KMSP/
SAT...MVFR CIGS POSSIBLE. SHRA LIKELY. WINDS WNW 5-10 KTS.
SUN...MVFR CIGS POSSIBLE EARLY. WINDS N 5 KTS.
MON...VFR. WINDS SE 5 KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
SHORT TERM...MPG
LONG TERM...DWE
AVIATION...LS
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
524 AM CDT THU MAY 30 2013
.UPDATE...
12Z AVIATION DISCUSSION ADDED BELOW.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 353 AM CDT THU MAY 30 2013
A VERY ACTIVE SHORT TERM IS IN STORE AS A POTENT UPPER WAVE WORKS
ACROSS THE NATIONS MIDSECTION. H5 RAP ANALYSIS SHOWS A CLOSED LOW
HAS DEVELOPED NEAR THE BLACK HILLS THIS MORNING...WITH A NEGATIVELY
TITLED TROUGH EXTENDING FROM THERE DOWN TO NORTHEAST TEXAS. THE
RADAR MOSAIC WEDNESDAY WAS CRAMMED FULL OF CONVECTION FROM HERE ALL
THE WAY DOWN TO TEXAS...WHICH MEANS WITHIN THIS LARGE SCALE TROUGH
THERE ARE NUMEROUS LEFT OVER WAVES/MCVS. ONE SUCH WAVE IS OVER SW IA
THAT WILL SWING THROUGH HERE IN THE LATE MORNING. THE MAIN SYNOPTIC
UPPER WAVE WILL BEGIN WORKING ACROSS MN THIS AFTERNOON AND EVENING.
TO GO ALONG WITH ALL OF THE WAVES...A 50 KT LLJ IS CURRENTLY BLOWING
ACROSS MN. THIS LLJ WILL SLOWLY DIMINISH THROUGH THE MORNING...BUT A
MUCH STRONGER PUSH CURRENTLY OVER OK/KS WILL COME UP INTO SE MN/WRN
WI THIS AFTERNOON/EVENING WITH THE PRIMARY SYNOPTIC WAVE.
AT THE SFC...A 995 MB SFC LOW CAN BE FOUND NEAR PIERRE SOUTH
DAKOTA...WITH A WARM FRONT SITTING ACROSS CENTRAL MN. DURING THE
SHORT TERM...THIS LOW WILL BECOME OCCLUDED AND SLOWLY MEANDER NORTH
INTO NODAK. THE WARM FRONT WILL CONTINUE TO MOVE NORTH
TODAY...EVENTUALLY SETTLING ALONG THE INTERNATIONAL BORDER. BACK TO
THE WEST...A COLD FRONT MOVING ACROSS SODAK TODAY WILL BE ENTERING
WRN MN BY THE END OF THE PERIOD.
FOR TODAY...EXPECT A BRIEF LULL IN ACTIVITY THIS MORNING AS WE WAIT
FOR THE WAVE OVER SW IA TO GET HERE AROUND 15Z. FORECAST SOUNDINGS
ACROSS THE ENTIRE CWA SHOW VERY LITTLE IF ANY CAPPING...SO EXPECT
SHOWERS AND STORMS TO DEVELOP QUICKLY THIS MORNING ONCE A LITTLE
DAYTIME HEATING KICKS IN. SINCE WE WILL NOT BE ABLE TO BUILD MUCH
INSTABILITY THANKS TO DENSE CLOUD COVER AND THE FACT THAT ONCE A
LITTLE DEVELOPS THE ATMO WILL QUICKLY CONSUME IT...THE SEVERE THREAT
LOOKS FAIRLY LOW TODAY. FOR SEVERE WEATHER...WILL HAVE TO WATCH THAT
SECOND LLJ WORKING UP IN THE AFTERNOON. BY 00Z THE RAP HAS 50 KT
WINDS AT H85 UP INTO OUR WI CWA. LIKE YESTERDAY...THIS COULD LEAD TO
THE THREAT FOR BOWING LINE SEGMENTS AND DAMAGING WINDS.
AS FOR ANY HYDROLOGY ISSUES TODAY...THE ONLY AREA THAT WILL
PROBABLY HAVE TO BE WATCHED IS THE EAU CLAIRE AREA. THEY SET A DAILY
RAINFALL RECORD YESTERDAY AND WILL BE UNDER THE GUN FOR THE SECOND
LLJ SURGE THIS AFTERNOON...WITH THE POTENTIAL FOR SOME TRAINING OF
STORMS THIS AFTERNOON AND EVENING.
TONIGHT...THE COLD FRONT WILL START ENTERING WRN MN WHILE THE LLJ
WORKS INTO CENTRAL/ERN WI. THIS SHOULD MOVE THE HEAVY RAIN THREAT
EAST OF THE MPX CWA TONIGHT. HOWEVER...HI-RES CAMS SHOW SCT RETURNS
CONTINUING THROUGH THE NIGHT AHEAD OF THE FRONT...SO HAVE POPS
SLOWLY RAMPING DOWN FROM LIKELIES TO START THE EVENING...DOWN TO 50%
POPS OR LESS BY 12Z FRIDAY.
FOR TEMPERATURES...GIVEN ALL OF THE CLOUD COVER...IT WILL NOT BE AN
OVERLY WARM WARM SECTOR TODAY...WITH HIGHS LIKELY STAYING IN THE MID
TO UPPER 70S...DESPITE H85 TEMPS BEING UP AROUND +15C. FOR
TONIGHT...MIXED LAYER DEWPS ON THE NAM DROP INTO THE 40S BEHIND THE
FRONT...SO LOWS IN THE WRN CWA COULD END UP BEING A FEW DEGREES
COOLER THAN WHAT IS CURRENTLY INDICATED.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 353 AM CDT THU MAY 30 2013
MODELS INDICATE RATHER STRONG TROUGH AXIS WORKING THROUGH THE
AREA BY FRIDAY MORNING. THIS SHOULD WORK MUCH OF THE RAIN AND
THUNDER TO THE NORTH AND EAST OF THE AREA LATE THURSDAY NIGHT.
THIS SHOULD WORK A DRY SLOT NORTHEAST INTO SOUTHWEST PORTION OF
THE CWA DURING FRIDAY MORNING. THE UPPER CIRCULATION THEN MOVES A
FRONTAL BOUNDARY EAST ACROSS EASTERN HALF OF THE CWA FRIDAY
AFTERNOON. THE DETERMINISTIC MODELS ARE INDICATING MODEST
DESTABILIZATION ACROSS THE EASTERN HALF OF THE AREA...WITH ML
MUCAPE INCREASING TO 1500/2000 J/KG. SHEAR INCREASES INTO THE
AFTERNOON...ESPECIALLY INTO WESTERN WISCONSIN. THE ONLY INHIBITING
FACTOR FOR CONVECTIVE INITIATION ALONG THE FRONT APPEARS TO BE
RATHER WEAK SURFACE CONVERGENCE..WITH WINDS S-SW ALONG THE
BOUNDARY. THE HIRES MODELS ARE SHOWING RATHER ROBUST CONVECTION
DEVELOPING ALONG THE BOUNDARY AS IT MOVES INTO EASTERN MINNESOTA
FRIDAY AFTERNOON. WILL HAVE TO MONITOR THIS SITUATION INTO
FRIDAY...AS SEVERE WEATHER THREAT IS FORECAST TO BE LOW AT THIS
TIME.
FRONT EXITS TO THE EAST FRIDAY NIGHT TAKING THE HEAVY CONVECTIVE
POTENTIAL WITH IT. THIS WILL LEAVE THE UPPER LOW OVER THE AREA
THROUGH AT LEAST SATURDAY. SHOWERS LOOK TO BE A FAIR BET
ESPECIALLY LATER IN THE DAY AS THE LOW MOVES EAST. WITH ABUNDANT
CLOUD COVER...WILL BE LITTLE IN THE WAY OF HEATING...SO CONVECTIVE
POTENTIAL IS LOW. CLEARING SHOULD MOVE INTO THE AREA LATER
SATURDAY NIGHT...AND SUNDAY LOOKS LIKE THE BEST DAY OF THE
WEEKEND...WITH SUNSHINE AND MILD TEMPERATURES.
THE EXTENDED PORTION OF THE FORECAST STARTS OFF RATHER
COOL...ESPECIALLY OVER THE EASTERN CWA MONDAY MORNING. THERE MAY
EVEN BE A FROST POTENTIAL OVER A PORTION OF WEST CENTRAL
WISCONSIN. THE NEXT WEATHER SYSTEM MOVES INTO THE AREA LATER
MONDAY WITH SOME SHOWERS INTO THE WESTERN CWA. THE 00Z GFS AND
ECMWF DIVERGE SOMEWHAT ON THE OVERALL EVOLUTION AND MOVEMENT OF
THE NEXT LOW PRESSURE SYSTEM THAT MOVES ACROSS THE NORTHERN STATES
THROUGH MUCH OF NEXT WEEK. IT DOES APPEAR THE THREAT OF MORE
SHOWERS AND THUNDERSTORMS RETURNS BY MIDWEEK...WITH TEMPERATURES
REMAINING BELOW NORMAL THROUGH THE PERIOD.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 523 AM CDT THU MAY 30 2013
ALL SIGNS POINT TO ANOTHER ACTIVE DAY AS THE MPX AREAS SITS IN A
MOIST...UNSTABLE...AND WEAKLY CAPPED ENVIRONMENT. THERE IS NO REAL
FOCUSING MECHANISM FOR STORMS TODAY...INSTEAD...EXPECT CONVECTION
TO QUICKLY DEVELOP ONCE WE GET A LITTLE INSTABILITY...AS THE
HRRR SHOWS HAPPENING RAPIDLY AFTER 15Z. DID ADD SOME TEMPO GROUPS
FOR THUNDER EARLY THIS AFTERNOON...BUT COULD CERTAINLY SEE A
COUPLE ROUNDS OF STORMS THROUGH THE EVENING...ESPECIALLY FOR MSP
AND WI TERMINALS. TONIGHT...A COLD FRONT WILL MOVE INTO WRN
MN...THOUGH IT ONLY LOOKS TO GET THROUGH RWF BY 12Z. BEING EAST OF
THE FRONT STILL TONIGHT...EXPECT A SIMILAR TREND IN SHRA/TSRA
ACTIVITY AS TO WHAT WAS SEEN LAST NIGHT. FOR CIGS...BEING MAINLY
SOUTH OF THE WARM FRONT...EXPECT SPORADIC IFR/MVFR CIGS TO QUICKLY
LIFT THIS MORNING...WITH VFR CIGS REMAINING OUTSIDE OF TSRA.
DEPENDING HOW MUCH RAIN IS SEEN IN WI...MAY SEE MVFR CIGS RETURN
THERE TONIGHT...BUT NOT OVERLY CONFIDENT ON THAT HAPPENING AT THE
MOMENT.
KMSP...HIGH CONFIDENCE IN STORMS OCCURRING TODAY...BUT WITH NO
DEFINITIVE FRONT COMING THROUGH...CONFIDENCE IS LOW ON EXACT
TIMING...OR EVEN EXACT NUMBER OF STORMS MSP WILL SEE TODAY INTO
TONIGHT. FOR NOW...INSERTED A TEMPO GROUP FROM 18Z TO 21Z PER
CONVECTIVE COVERAGE ON THE HRRR. WITH THE FRONT NEVER GETTING
THROUGH THE FIELD THIS PERIOD...MAY SEE PERIODS OF SHOWERS THROUGH
THE NIGHT...THOUGH EXPECT SHRA/TSRA ACTIVITY TO DECREASE
CONSIDERABLY AFTER SUNSET. BY 18Z FRIDAY OR SHORTLY AFTER...WILL
HAVE TO START THINKING ABOUT THE NEXT POTENTIAL ROUND OF TSRA.
/OUTLOOK FOR KMSP/
FRI...SCT MVFR CIGS. SHRA/TSRA LIKELY. WINDS SW 10-15 KTS.
SAT...MVFR CIGS POSSIBLE. SHRA LIKELY. WINDS WNW 5-10 KTS.
SUN...MVFR CIGS POSSIBLE EARLY. WINDS N 5 KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
SHORT TERM...MPG
LONG TERM...DWE
AVIATION...MPG
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
353 AM CDT THU MAY 30 2013
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 353 AM CDT THU MAY 30 2013
A VERY ACTIVE SHORT TERM IS IN STORE AS A POTENT UPPER WAVE WORKS
ACROSS THE NATIONS MIDSECTION. H5 RAP ANALYSIS SHOWS A CLOSED LOW
HAS DEVELOPED NEAR THE BLACK HILLS THIS MORNING...WITH A NEGATIVELY
TITLED TROUGH EXTENDING FROM THERE DOWN TO NORTHEAST TEXAS. THE
RADAR MOSAIC WEDNESDAY WAS CRAMMED FULL OF CONVECTION FROM HERE ALL
THE WAY DOWN TO TEXAS...WHICH MEANS WITHIN THIS LARGE SCALE TROUGH
THERE ARE NUMEROUS LEFT OVER WAVES/MCVS. ONE SUCH WAVE IS OVER SW IA
THAT WILL SWING THROUGH HERE IN THE LATE MORNING. THE MAIN SYNOPTIC
UPPER WAVE WILL BEGIN WORKING ACROSS MN THIS AFTERNOON AND EVENING.
TO GO ALONG WITH ALL OF THE WAVES...A 50 KT LLJ IS CURRENTLY BLOWING
ACROSS MN. THIS LLJ WILL SLOWLY DIMINISH THROUGH THE MORNING...BUT A
MUCH STRONGER PUSH CURRENTLY OVER OK/KS WILL COME UP INTO SE MN/WRN
WI THIS AFTERNOON/EVENING WITH THE PRIMARY SYNOPTIC WAVE.
AT THE SFC...A 995 MB SFC LOW CAN BE FOUND NEAR PIERRE SOUTH
DAKOTA...WITH A WARM FRONT SITTING ACROSS CENTRAL MN. DURING THE
SHORT TERM...THIS LOW WILL BECOME OCCLUDED AND SLOWLY MEANDER NORTH
INTO NODAK. THE WARM FRONT WILL CONTINUE TO MOVE NORTH
TODAY...EVENTUALLY SETTLING ALONG THE INTERNATIONAL BORDER. BACK TO
THE WEST...A COLD FRONT MOVING ACROSS SODAK TODAY WILL BE ENTERING
WRN MN BY THE END OF THE PERIOD.
FOR TODAY...EXPECT A BRIEF LULL IN ACTIVITY THIS MORNING AS WE WAIT
FOR THE WAVE OVER SW IA TO GET HERE AROUND 15Z. FORECAST SOUNDINGS
ACROSS THE ENTIRE CWA SHOW VERY LITTLE IF ANY CAPPING...SO EXPECT
SHOWERS AND STORMS TO DEVELOP QUICKLY THIS MORNING ONCE A LITTLE
DAYTIME HEATING KICKS IN. SINCE WE WILL NOT BE ABLE TO BUILD MUCH
INSTABILITY THANKS TO DENSE CLOUD COVER AND THE FACT THAT ONCE A
LITTLE DEVELOPS THE ATMO WILL QUICKLY CONSUME IT...THE SEVERE THREAT
LOOKS FAIRLY LOW TODAY. FOR SEVERE WEATHER...WILL HAVE TO WATCH THAT
SECOND LLJ WORKING UP IN THE AFTERNOON. BY 00Z THE RAP HAS 50 KT
WINDS AT H85 UP INTO OUR WI CWA. LIKE YESTERDAY...THIS COULD LEAD TO
THE THREAT FOR BOWING LINE SEGMENTS AND DAMAGING WINDS.
AS FOR ANY HYDROLOGY ISSUES TODAY...THE ONLY AREA THAT WILL
PROBABLY HAVE TO BE WATCHED IS THE EAU CLAIRE AREA. THEY SET A DAILY
RAINFALL RECORD YESTERDAY AND WILL BE UNDER THE GUN FOR THE SECOND
LLJ SURGE THIS AFTERNOON...WITH THE POTENTIAL FOR SOME TRAINING OF
STORMS THIS AFTERNOON AND EVENING.
TONIGHT...THE COLD FRONT WILL START ENTERING WRN MN WHILE THE LLJ
WORKS INTO CENTRAL/ERN WI. THIS SHOULD MOVE THE HEAVY RAIN THREAT
EAST OF THE MPX CWA TONIGHT. HOWEVER...HI-RES CAMS SHOW SCT RETURNS
CONTINUING THROUGH THE NIGHT AHEAD OF THE FRONT...SO HAVE POPS
SLOWLY RAMPING DOWN FROM LIKELIES TO START THE EVENING...DOWN TO 50%
POPS OR LESS BY 12Z FRIDAY.
FOR TEMPERATURES...GIVEN ALL OF THE CLOUD COVER...IT WILL NOT BE AN
OVERLY WARM WARM SECTOR TODAY...WITH HIGHS LIKELY STAYING IN THE MID
TO UPPER 70S...DESPITE H85 TEMPS BEING UP AROUND +15C. FOR
TONIGHT...MIXED LAYER DEWPS ON THE NAM DROP INTO THE 40S BEHIND THE
FRONT...SO LOWS IN THE WRN CWA COULD END UP BEING A FEW DEGREES
COOLER THAN WHAT IS CURRENTLY INDICATED.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 353 AM CDT THU MAY 30 2013
MODELS INDICATE RATHER STRONG TROUGH AXIS WORKING THROUGH THE
AREA BY FRIDAY MORNING. THIS SHOULD WORK MUCH OF THE RAIN AND
THUNDER TO THE NORTH AND EAST OF THE AREA LATE THURSDAY NIGHT.
THIS SHOULD WORK A DRY SLOT NORTHEAST INTO SOUTHWEST PORITON OF
THE CWA DURING FRIDAY MORNING. THE UPPER CIRCULATION THEN MOVES A
FRONTAL BOUNDARY EAST ACROSS EASTERN HALF OF THE CWA FRIDAY
AFTERNOON. THE DETERMINISTIC MODELS ARE INDICATING MODEST
DESTABILIZATION ACROSS THE EASTERN HALF OF THE AREA...WITH ML
MUCAPE INCREASING TO 1500/2000 J/KG. SHEAR INCREASES INTO THE
AFTERNOON...ESPECIALLY INTO WESTERN WISCONSIN. THE ONLY INHIBITING
FACTOR FOR CONVECTIVE INITIATION ALONG THE FRONT APPEARS TO BE
RATHER WEAK SURFACE CONVERGENCE..WITH WINDS S-SW ALONG THE
BOUNDARY. THE HIRES MODELS ARE SHOWING RATHER ROBUST CONVECTION
DEVELOPING ALONG THE BOUNDAY AS IT MOVES INTO EASTERN MINNESOTA
FRIDAY AFTERNOON. WILL HAVE TO MONITOR THIS SITUATION INTO
FRIDAY...AS SEVERE WEATHER THREAT IS FORECAST TO BE LOW AT THIS
TIME.
FRONT EXITS TO THE EAST FRIDAY NIGHT TAKING THE HEAVY CONVECTIVE
POTENTIAL WITH IT. THIS WILL LEAVE THE UPPER LOW OVER THE AREA
THROUGH AT LEAST SATURDAY. SHOWERS LOOK TO BE A FAIR BET
ESPECIALLY LATER IN THE DAY AS THE LOW MOVES EAST. WITH ABUNDANT
CLOUD COVER...WILL BE LITTLE IN THE WAY OF HEATING...SO CONVECTIVE
POTENTIAL IS LOW. CLEARING SHOULD MOVE INTO THE AREA LATER
SATURDAY NIGHT...AND SUNDAY LOOKS LIKE THE BEST DAY OF THE
WEEKEND...WITH SUNSHINE AND MILD TEMPERATURES.
THE EXTENDED PORTION OF THE FORECAST STARTS OFF RATHER
COOL...ESPECIALLY OVER THE EASTERN CWA MONDAY MORNING. THERE MAY
EVEN BE A FROST POTENTIAL OVER A PORTION OF WEST CENTRAL
WISCONSIN. THE NEXT WEATHER SYSTEM MOVES INTO THE AREA LATER
MONDAY WITH SOME SHOWERS INTO THE WESTERN CWA. THE 00Z GFS AND
ECMWF DIVERGE SOMEWHAT ON THE OVERALL EVOLUTION AND MOVEMENT OF
THE NEXT LOW PRESSURE SYSTEM THAT MOVES ACROSS THE NORTHERN STATES
THROUGH MUCH OF NEXT WEEK. IT DOES APPEAR THE THREAT OF MORE
SHOWERS AND THUNDERSTORMS RETURNS BY MIDWEEK...WITH TEMPERATURES
REMAINING BELOW NORMAL THROUGH THE PERIOD.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1254 AM CDT THU MAY 30 2013
WITH THE NOSE OF A 40 KT LLJ SLOWLY WORKING ACROSS THE MPX AREA
THIS PERIOD...FULLY EXPECT SEVERAL ROUNDS OF SHRA/TSRA THE REST OF
TONIGHT THROUGH THU NIGHT. CONFIDENCE IS HIGH IN CONVECTIVE
OCCURRENCE...BUT LIMITED ON EXACT TIMING AND PLACEMENT BEYOND THE
FIRST 6 HOURS OF THE TAF...SO STUCK WITH LOTS OF VC GROUPS FOR NOW.
STORM INTENSITY HAS BEEN SLOWLY DIMINISHING THE LAST COUPLE OF
HOURS...AND EXPECT THIS TO CONTINUE THE REST OF THE EVENING.
EXPECT A BRIEF LULL IN ACTIVITY LATE TONIGHT INTO THU
MORNING...BEFORE SHRA/TSRA ACTIVITY QUICKLY FIRES UP AGAIN AFTER
15Z. SOUNDINGS THROUGH THURSDAY SHOW VERY LITTLE INHIBITION...SO
SHOULD NOT TAKE MUCH TO GET STORMS GOING THIS WHOLE PERIOD. FOR
CIGS...EXPECT THEM TO REMAIN MAINLY VFR OUTSIDE OF SHRA/TSRA
ACTIVITY...THOUGH GIVEN DEGREE OF LOW LEVEL MOISTURE IN PLACE...WE
COULD SEE SOME POCKETS OF MVFR CIGS DEVELOP THIS MORNING BEFORE
QUICKLY LIFTING.
KMSP...STORMS STARTING TO DIMINISH IN INTENSITY THIS EVENING AND
EXPECT A LULL IN ACTIVITY BETWEEN ABOUT 10Z AND 15Z AS THE ATMO
RECHARGES. EXPECT A QUICK RETURN TO SHRA/TSRA ACTIVITY IN THE
MORNING...AS EVIDENCED BY THE HRRR...WHICH HAS STORMS DEVELOPING
OVER MN BY 16Z. WINDS WILL REMAIN STRONG THROUGH THE PERIOD...BUT
WILL BE FAIRLY PERSISTENT BETWEEN 140 AND 170 DEGS OUTSIDE OF ANY
STORMS. ONLY TIME PERSISTENT MVFR CIGS ARE EXPECTED THIS PERIOD IS
DURING PERIODS OF SHRA/TSRA.
/OUTLOOK FOR KMSP/
FRI...SCT MVFR CIGS. SHRA/TSRA LIKELY. WINDS SW 10-15 KTS.
SAT...MVFR CIGS POSSIBLE. SHRA LIKELY. WINDS WNW 5-10 KTS.
SUN...MVFR CIGS POSSIBLE EARLY. WINDS N 5 KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
SHORT TERM...MPG
LONG TERM...DWE
AVIATION...MPG
AREA FORECAST DISCUSSION...UPDATED
NWS BILLINGS MT
806 PM MDT FRI MAY 31 2013
.UPDATE...
WE UPDATED THE FORECAST IN ORDER TO ALIGN EVENING POPS WITH RECENT
RADAR TRENDS...WHICH MEANT INCREASING THEM UP INTO THE CATEGORICAL
RANGE THROUGH 06 UTC WHERE IT IS RAINING NOW...AND LOWERING THEM A
LOT AFTER 06 UTC. THE LAST BATCH OF RAINFALL IS WORKING ITS WAY TO
THE WEST-SOUTHWEST THROUGH SOUTH CENTRAL MT AS OF 02 UTC...AND THE
BACK EDGE SHOULD PROGRESS THROUGH BILLINGS BEFORE 04 UTC. BASED ON
THESE TRENDS AND RECENT RAP GUIDANCE...WE FELT COMFORTABLE SHOWING
A DRY FORECAST AFTER 06 UTC OVER MUCH OF THE AREA. WE DID LEAVE IN
SOME CHANCE-STYLE POPS IN THE 30 TO 50 PERCENT RANGE FROM SHERIDAN
TO BROADUS AND EKALAKA THROUGH THE NIGHT THOUGH SINCE THE RAIN MAY
NEED A BIT OF TIME TO COMPLETELY DIMINISH AS FORCING WANES.
BASED ON A RELAXING LOW- AND MID-LEVEL PRESSURE GRADIENT...AND THE
GENERAL DOWNWARD TREND IN OBSERVED WIND SPEEDS ACROSS SOUTHERN BIG
HORN AND SHERIDAN COUNTIES...WE LET THE HIGH WIND WARNING THERE GO
A BIT EARLY. OTHERWISE...ONLY MINOR CHANGES WERE MADE TO TONIGHT/S
FORECAST. SCHULTZ
&&
.SHORT TERM...VALID FOR SAT AND SUN...
DRYING WAS WORKING TOWARD THE FORECAST AREA FROM NE MT AS
EVIDENCED BY VISIBLE SATELLITE IMAGERY AND GGW RADAR LOOP. UPPER
LOW CENTERED OVER THE EASTERN DAKOTAS ON WATER VAPOR IMAGERY
CONTINUED TO WRAP MOISTURE BACK AROUND INTO THE FORECAST AREA THIS
AFTERNOON. HOWEVER...A SHORTWAVE MOVING AROUND THE LOW THROUGH NE
MT WILL USHER SUBSIDENCE INTO THE AREA TONIGHT...WHICH WILL ALLOW
THE RAIN TO SLOWLY TAPER OFF FROM N TO S OVER CENTRAL AND EASTERN
PARTS OF THE AREA. A WEAK WAVE WILL APPROACH FROM THE W SUPPORTING
A CONTINUED CHANCE OF SHOWERS W OF KBIL OVERNIGHT. WINDS WERE
GUSTING INTO THE 40S OVER CENTRAL AND WESTERN PARTS OF THE AREA
THIS AFTERNOON. WINDS WERE MEETING HIGH WIND CRITERIA ON THE MT/WY
BORDER ALONG THE SHERIDAN COUNTY LINE. WILL KEEP THE HIGH WIND
WARNING GOING THROUGH 03Z BY WHICH TIME THE AIRMASS WILL DECOUPLE
AND THE STRONG 850-700 MB JET WILL MOVE S OF THE AREA. FLOOD
ADVISORIES CONTINUE THROUGH THIS EVENING OR SAT MORNING DUE TO
POOR TRAVEL CONDITIONS FROM MINOR FLOODING...POSSIBLE BURN SCAR
DEBRIS FLOWS AND MINOR STREAM FLOODING. WILL BE CANCELING THE
FLASH FLOOD WATCH AS FLOOD ADVISORIES WERE COVERING THE AREAS OF
CONCERN AND CONVECTION IS NOT EXPECTED.
KEPT SOME LINGERING POPS OVER THE AREA SAT MORNING FOR THE
DEPARTING SYSTEM AND THE WESTERN SHORTWAVE. SAT AFTERNOON WILL BE
DRY. HIGH TEMPERATURES IN THE 60S WERE IN GOOD SHAPE. DRY WEATHER
WILL CONTINUE SAT NIGHT AHEAD OF THE NEXT PACIFIC SYSTEM. RAIN
CHANCES WILL INCREASE OVER THE REGION AGAIN SUN THROUGH SUN NIGHT.
UPPER DIFFLUENCE WILL PRECEDE THE NEXT LOW ON SUN BRINGING A
CHANCE OF SHOWERS AND A SLIGHT CHANCE OF THUNDERSTORMS TO AREAS W
AND N OF KBIL DURING THE AFTERNOON. THE UPPER LOW WILL MOVE INTO W
MT SUN NIGHT BRINGING THE LIKELIHOOD OF PRECIPITATION TO AREAS W
AND N OF KBIL AND A CHANCE OF PRECIPITATION ELSEWHERE. MODELS
HINTED AT A DRY SLOT OVER FAR S CENTRAL/SE PORTIONS OF THE AREA
SUN NIGHT. POPS IN THESE AREAS MAY NEED TO BE LOWERED IF THIS
TREND CONTINUES IN THE MODELS. STRONG SE FLOW AND PRECIPITATION
WILL HINDER THE EXTENT OF THE TEMPERATURE RISE ON SUN SO HAVE
TRENDED THE HIGHS DOWN SLIGHTLY. ARTHUR
.LONG TERM...VALID FOR MON...TUE...WED...THU...FRI...
ONLY MINOR CHANGES TO THE EXTENDED AS MEDIUM RANGE GUIDANCE IN
OVERALL GOOD AGREEMENT. OUR NEXT SYSTEM WILL APPROACH FOR LATE
MONDAY INTO TUESDAY. THIS SYSTEM EXPECTED TO TRACK JUST OFF TO OUR
NORTH ACROSS NORTHERN MONTANA...SO NOT AN IDEAL TRACK FOR ANOTHER
SIGNIFICANT OR WIDESPREAD PRECIPITATION AS SYSTEM WILL BE FIGHTING
DOWNSLOPE WINDS. ALTHOUGH...DYNAMICS AHEAD OF SYSTEM WILL BE
SUFFICIENT TO PRODUCE SCATTERED THUNDERSTORMS WITH COLD FRONTAL
PASSAGE WHICH COULD BE LOCALLY STRONG. WEAK RIDGING BUILDS IN FOR
WED-FRI TIMEFRAME...SO MOSTLY DRY CONDITIONS WILL BE NOTED.
TEMPERATURES WILL BE RUNNING CLOSE TO NORMAL THROUGH THE PERIOD.
DID COOL TEMPERATURES SLIGHTLY INTO TUESDAY WITH COLD AIR
ADVECTION BEING THE COLD FRONT. FRIEDERS
&&
.AVIATION...
MVFR CONDITIONS ARE EXPECTED IN MOST AREAS THIS EVENING BEFORE
THE RAINFALL ENDS FROM NORTH TO SOUTH OVERNIGHT. WINDS WILL ALSO
CONTINUE TO DECREASE OVERNIGHT. MOUNTAIN OBSCURATIONS WILL BE
POSSIBLE OVERNIGHT. CONDITIONS WILL IMPROVE TO VFR SATURDAY
MORNING WITH LIGHTER WINDS ACROSS THE AREA. CHURCH
&&
.PRELIMINARY POINT TEMP/POPS...
SAT SUN MON TUE WED THU FRI
-----------------------------------------------------------
BIL 045/067 048/075 052/068 048/066 049/072 052/076 053/078
92/R 01/B 55/T 33/T 11/B 11/B 12/T
LVM 037/067 041/073 043/066 043/064 041/072 045/074 046/076
31/B 02/T 65/T 33/T 21/U 12/T 23/T
HDN 045/068 045/077 051/070 048/067 046/073 050/076 053/081
+3/R 01/B 33/T 33/T 11/B 11/B 12/T
MLS 044/066 046/074 051/069 048/066 047/071 051/075 053/078
21/B 01/B 45/T 44/T 21/B 11/U 12/T
4BQ 042/064 043/074 048/070 046/064 046/069 047/074 051/078
92/R 00/B 34/T 33/T 11/B 11/U 12/T
BHK 040/062 040/069 045/067 044/062 043/066 046/071 049/074
72/R 01/B 55/T 44/T 22/T 11/B 12/T
SHR 041/063 041/075 047/070 046/064 043/068 045/073 048/076
62/R 01/B 23/T 33/T 22/T 12/T 23/T
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...NONE.
WY...NONE.
&&
$$
WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION
NWS GLASGOW MT
258 AM MDT THU MAY 30 2013
.SHORT TERM...FOR NORTHEAST MONTANA...TODAY THROUGH SATURDAY...
RAIN...HEAVY IN SOME AREAS... CONTINUE TO FALL OVER THE SW HALF OF
THE FORECAST AREA EARLY THIS MORNING. RAINFALL TOTALS HAVE
EXCEEDED 2 INCHES AT JORDAN AIRPORT IN CENTRAL GARFIELD COUNTY AND
AT BIG SHEEP MOUNTAIN RAWS IN WESTERN PRAIRIE COUNTY SINCE
WEDNESDAY AFTERNOON. THIS RAIN IS FOCUSED ALONG AN INVERTED
SURFACE TROUGH THAT IS NEAR WINNETT... FORSYTHE AND BROADUS OR JUST
SOUTH OF THE HEAVY PRECIP BAND.
AN UPPER LOW OVER NE WYOMING IS STACKED WITH THE SURFACE LOW OVER
NEBRASKA AT 09Z. THE SURFACE LOW WILL MOVE NORTH TODAY TAKING THE
RAIN NORTH WITH IT. THIS WILL SPREAD THE RAIN NORTH INTO THE NE
HALF OF THE FORECAST AREA THAT HAS STAYED DRY OVERNIGHT. BY THIS
EVENING...THE SURFACE LOW WILL BE IN NORTH DAKOTA WHILE THE UPPER
LOW WILL BE IN SOUTH DAKOTA. EASTERN MONTANA WILL BE IN THE WRAP
AROUND MOISTURE IN THIS SYSTEM AND WITH THE AID OF A TROWAL
(TROUGH OF WARM AIR ALOFT)... MODERATE TO HEAVY RAIN WILL CONTINUE
OVER THE AREA INTO FRIDAY. AN ADDITIONAL 2+ INCHES OF RAIN CAN BE
EXPECTED WITH THIS SYSTEM. WILL MAINTAIN FLOOD WATCH FOR THE
ENTIRE FORECAST AREA THROUGH FRIDAY.
THE SYSTEM WILL BEGIN TO MOVE TO THE EAST FRIDAY NIGHT WHICH WILL
TAKE THE MOISTURE WITH. DRIER AIR WILL MOVE IN FROM THE NORTH
ENDING THE RAIN.
A SHORTWAVE RIDGE AND SURFACE HIGH PRESSURE WILL BRING DRY
WEATHER ON SATURDAY. FORRESTER
.LONG TERM...SATURDAY NIGHT THROUGH THURSDAY...
SYNOPTIC SET UP... A LARGE TROUGH EXTENDS FROM THE HUDSON BAY
DOWN INTO THE CENTRAL US PLAINS WHILE A SECOND ONE RUNS FROM THE
THE PACIFIC NORTHWEST ALONG THE BRITISH COLUMBIAN SHORE AND BACK TO
THE GULF OF ALASKA. A WEAK TROUGH RIDGE IS WEDGED BETWEEN THESE
TWO LARGE FEATURES FROM UTAH THROUGH CENTRAL MONTANA AND UP INTO
THE NORTHWEST TERRITORIES.
SATURDAY NIGHT... UPPER SHORTWAVE RIDGE PUSHES INTO NORTHEAST
MONTANA IN THE WAKE OF THE LARGE STORM SYSTEM WHICH WILL LEAD TO
MUCH DRIER CONDITIONS. POPS WERE TRENDED DOWN TO NON MENTION
THROUGH SATURDAY NIGHT AS ENSEMBLE MODELS ARE PLACING NO QPF
ACROSS THE AREA AND DRY AIR FROM CANADA IS ANTICIPATED TO ENTER.
SUNDAY INTO TUESDAY... MODELS CONTINUE TO HINT AT THE POTENTIAL
FOR CONVECTION INITIATION AS A SHORTWAVE TROUGH BREAKS DOWN THE
RIDGE ALOFT AND INTERACTS WITH A DEVELOPING THETA-E RIDGE. MODELS
DIFFER ON TIMING AND PLACEMENT OF THIS WAVE AS WELL AS INTENSITY.
THE LATEST EC AND GFS HAVE INITIATION OVER GREAT FALL TERRITORY
AND JUST OFF THE FRONT RANGE. THEN BECOMING A MORE NOCTURNAL EVENT
FOR THE GGW CWA. IF THIS VERIFIED... SOME STORMS COULD BECOME
STRONG WITH A GOOD LIGHTNING SHOW... BUT LOCALLY SEVERE WEATHER
MIGHT BE HARDER TO COME BY THAN PREVIOUS RUNS PREDICTED. A SECOND
ROUND OR STRONG THUNDER IS POSSIBLE MONDAY AFTERNOON AND
EVENING... BUT SHOULD THE CENTER OF THE MID LEVEL LOW THAT WRAPS
UP PASSING GGW BEFORE THE AFTERNOON CONDITIONS WILL QUICKLY BECOME
LESS FAVORABLE. THUS...CONFIDENCE IS INCREASING ON MORE RAINFALL
MONDAY AND MONDAY EVENING. BUT THE DETAILS SUCH AS TIMING AND
PLACEMENT AND HOW STRONG THE STORMS WILL BE WILL STILL NEED TO BE
WORKED OUT WITH LATER SHIFTS. MODELS STILL INDICATE A STRONG UPPER
LEVEL JET STREAK OVER THE AREA SOMETIME LATE WEEKEND WHICH COULD
MIX DOWN IN STORMS IF TIMING IS RIGHT.
TUESDAY NIGHT AND BEYOND... MULTI MODEL ENSEMBLES BECOME
INCREASINGLY IN DISAGREEMENT AT THIS POINT INDICATING LOWER
CONFIDENCE. WHAT CAN BE INFERRED FROM THE TEA LEAVES IS A RIDGE
BUILDING ACROSS THE HIGH PLAINS THROUGH WEDNESDAY NIGHT ALLOWING
FOR A WARMING TREND THROUGH MID WEEK AND BUMPING UP DAYTIME HIGHS.
AFTERWARD A TROUGH BEHIND THIS RIDGE IS EXPECTED TO ROLL INTO THE
PACIFIC NORTHWEST AROUND THURSDAY. THIS WOULD SEND SHORTWAVES
ZOOMING OVER THE HIGH PLAINS AND NORTHEAST MONTANA AND COULD
GENERATE A BIT OF CONVECTION. GAH/MALIAWCO
&&
.AVIATION...
VFR TO MVFR VISIBILITIES UNDER RAIN SHOWERS. IFR CEILINGS POSSIBLE
ELSEWHERE.
ON AND OFF SHOWERS WILL CONTINUE THROUGH KGDV AND KGGW WHILE KOLF
AND KSDY SHOULD REMAIN CLEAR OF RAIN THROUGH 09Z. HRRR GUIDANCE
SUGGESTS A WINDOW OF CLEARING RAIN BETWEEN 09Z TO 12Z MOVING FROM
EAST TO WEST WITH THE KGGW TERMINAL POSSIBLY BEING CLEAR OF RAIN
THROUGH NEARLY 15Z. AFTERWARD... ANOTHER LARGE BAND OF RAIN WITH
MVFR CONDITIONS IS PROGGED THROUGH THE END OF THE TAF CYCLE.
WHILE SOME AREAS MAY CLEAR FROM RAIN...RAIN FREE AREAS MAY
ACTUALLY BECOME WORSE WITH TEMPORARY IFR CONDIITONS DUE TO CEILINGS
DROPPING IN WHAT WOULD RAPIDLY BECOME COLDER LOCATIONS.
WINDS WILL BE EASTERLY BETWEEN 5 AND 15 KTS THROUGH TONIGHT...
THEN BECOME NORTHEASTERLY AND INCREASING TO 10 TO 20 KTS AFTER SUN
UP.
GAH
&&
.HYDROLOGY...
WITH RAINFALL HAVING EXCEEDED 2 INCHES ACROSS PARTS OF GARFIELD
AND WESTERN PRAIRIE COUNTIES BASED ON AUTOMATED GAGES AT JORDAN
AIRPORT AND BIG SHEEP MOUNTAIN RAWS... HAVE ISSUED A FLOOD WARNING
THAT IS IN EFFECT THROUGH 730 PM THIS EVENING. A FLOOD WATCH
REMAINS IN EFFECT FOR NORTHEAST MONTANA THROUGH FRIDAY. THIS WILL
LEAD TO RISES IN STREAMS AND CREEKS WITH MAINSTEM RIVERS ALSO
SEEING RISES BY THE WEEKEND INTO NEXT WEEK.
AN ADDITIONAL 2+ INCHES OF RAIN IS LIKELY BETWEEN TODAY AND FRIDAY
BEFORE THE SYSTEM MOVES TO THE EAST. FORRESTER
&&
.GLASGOW WATCHES/WARNINGS/ADVISORIES...
FLOOD WATCH THROUGH FRIDAY AFTERNOON FOR CENTRAL AND SOUTHEAST
PHILLIPS...CENTRAL AND SOUTHERN VALLEY...DANIELS...DAWSON...
EASTERN ROOSEVELT...GARFIELD...MCCONE...NORTHERN PHILLIPS...
NORTHERN VALLEY...PETROLEUM...PRAIRIE...RICHLAND...SHERIDAN...
SOUTHWEST PHILLIPS...WESTERN ROOSEVELT...WIBAUX.
&&
$$
WEATHER.GOV/GLASGOW
AREA FORECAST DISCUSSION
NWS HASTINGS NE
650 PM CDT FRI MAY 31 2013
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 319 PM CDT FRI MAY 31 2013
IN THE SYNOPTIC SCALE...THE LARGE UPPER LEVEL LOW PRESSURE SYSTEM
THAT HAS AFFECTED OUR WEATHER THE PAST FEW DAYS...CONTINUES TO SPIN
ACROSS THE DAKOTAS...WHILE RIDGING CONTINUES JUST OFF BOTH THE
WESTERN AND EASTERN COASTS. IN THE MID LEVELS...THIS SYSTEM
CONTINUES TO SURGE AN ABUNDANCE OF GULF COAST MOISTURE UP THE
MISSISSIPPI RIVER VALLEY INTO THE MIDWEST...AS SEEN IN RECENT
FLOODING ASSOCIATED WITH THUNDERSTORMS ACROSS THE COUNTRY`S
MIDSECTION. AT THE SURFACE...THE SYSTEM REMAINS NEARLY VERTICALLY
STACKED WITH LOW PRESSURE ALSO ALIGNED OVER THE DAKOTAS...AND A
SECONDARY LOW SITUATED SOUTH OF THE TROUGH AXIS ACROSS SOUTHEASTERN
KANSAS.
AS THE LOW PRESSURE SYSTEM CONTINUES TO SPIN...ALMOST NEARLY
STATIONARY...THE MAIN COLD FRONTAL BOUNDARY HAS ALREADY SHIFTED
THROUGH THE OUTLOOK AREA. HOWEVER...IT APPEARS A SECONDARY WEAK
TROUGH AXIS WILL ALSO SHIFT THROUGH THE AREA OVERNIGHT TONIGHT. WITH
THIS BOUNDARY...CONCERNS IN THE SHORT TERM WILL FOCUS MAINLY ON
PRECIPITATION CHANCES AND COOLER HIGH TEMPERATURES TOMORROW.
STARTING OFF THIS AFTERNOON...WATER VAPOR IMAGERY INDICATES THE
PRESENCE OF A WEAK SHORT WAVE TROUGH SLIDING THROUGH EASTERN
COLORADO SOUTH OF THE UPPER LEVEL LOW. AN AREA OF CUMULUS HAVE
DEVELOPED ACROSS THE AREA...AND BEGUN TO SPREAD NORTHEAST AS SEEN ON
VISIBLE SATELLITE. RADAR ALSO INDICATES AT LEAST SOME VERY LIGHT
RETURNS ACROSS NORTHWEST AND NORTH CENTRAL KANSAS. WENT AHEAD AND
PUT IN SLIGHT CHANCE POPS ACROSS NORTH CENTRAL KANSAS THROUGH THE
AFTERNOON...AS BOTH THE HRRR AND NAM MODEL SEEM TO BE HANDLING THIS
WELL. NOT EXPECTING MUCH MORE THAN A COUPLE SPRINKLES AND MAYBE A
RUMBLE OF THUNDER.
HEADING INTO THE OVERNIGHT HOURS...LATEST SATELLITE IMAGERY SHOWS
THE DEVELOPMENT OF A CUMULUS FIELD ACROSS MUCH OF NORTHWESTERN
NEBRASKA JUST BEHIND THE SECONDARY TROUGH AXIS. EXPECT THIS TROUGH
AXIS TO SLIDE THROUGH THE OUTLOOK AREA ROUGHLY AROUND 6Z...WITH WEST
WINDS SHIFTING TO THE NORTHWEST. CONTINUED SLIGHT POPS FOR THE
NORTHERN HALF OF THE OUTLOOK AREA OVERNIGHT...AS BOTH THE NAM AND
HRRR INDICATE AT LEAST SOME LIGHT SHOWERS TO PUSH THROUGH. THE UPPER
LEVEL LOW WILL FINALLY BEGIN TO SHIFT EASTWARD BY SATURDAY...THUS
DECREASING POPS FROM SOUTHWEST TO NORTHEAST THROUGHOUT THE DAY.
INSTABILITY THROUGHOUT MUCH OF THE SHORT TERM PERIOD...REMAINS
FAIRLY MINIMAL...WITH ONLY ABOUT 100 J/KG OR SO AT MOST. CONTINUED
WITH MENTION OF ONLY LIGHT RAIN SHOWERS AS A RESULT...AND LEFT OUT
MENTION OF THUNDER.
REGARDING TEMPERATURES ON SATURDAY...BEHIND THIS SECONDARY TROUGH
AXIS...COOLER AIR...WITH 850 MB TEMPERATURES ON THE ORDER OF 3 TO 4
DEGREES CELSIUS WILL SLIDE SOUTH INTO THE OUTLOOK AREA.
THUS...COMBINED WITH MODEL GUIDANCE...CONTINUED WITH TEMPERATURES IN
THE LOWER 60S ACROSS THE NORTH TO NEAR 70 IN NORTH CENTRAL KANSAS
FOR SATURDAY. SATURDAY LOOKS TO BE SHAPING INTO A FAIRLY UNPLEASANT
DAY...WITH MOSTLY CLOUDY SKIES AND COOLER TEMPERATURES. TO ADD TO
THE MIX...STRONG NORTHWEST WINDS SUSTAINED NEAR 20 KTS CAN BE
EXPECTED...AND WITH SOME MIXING WILL LEAD TO GUSTS NEAR 30 KTS.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 319 PM CDT FRI MAY 31 2013
MAIN FORECAST CONCERNS WILL BE CHANCES FOR THUNDERSTORMS AND
TEMPERATURES.
AN UPPER LEVEL SHORT WAVE RIDGE WILL MOVE ACROSS THE AREA SATURDAY
NIGHT THROUGH SUNDAY NIGHT. DURING THIS TIME DRY CONDITIONS ARE
EXPECTED. A SURFACE HIGH WILL SETTLE INTO THE AREA SATURDAY NIGHT
AND KEEP WINDS LIGHT AND TEMPERATURES WILL DROP TO THE 40S. BY
SUNDAY THE SURFACE HIGH WILL MOVE OFF TO THE EAST. WINDS WILL TURN
TO THE SOUTH AND AS THE PRESSURE GRADIENT TIGHTENS...THE WINDS WILL
INCREASE DURING THE DAY ON SUNDAY. TEMPERATURES WILL BE WARMER FOR
SUNDAY AND SUNDAY NIGHT.
FOR MONDAY THROUGH FRIDAY ANOTHER UPPER LEVEL LOW WILL WORK ITS WAY
FROM THE PACIFIC NORTHWEST...THROUGH THE NORTHERN ROCKIES AND INTO
THE NORTHERN PLAINS. THIS IS A SIMILAR TRACK TO THE ONE FROM THE
PAST WEEK. BY MONDAY THE UPPER LOW STARTS TO SEND THE FIRST SHORT
WAVE INTO THE AREA AND BRINGS A CHANCE FOR THUNDERSTORMS. MODELS
BRING SEVERAL SHORT WAVES THROUGH THE AREA DURING THE WEEK. THERE
ARE SOME MINOR TIMING DIFFERENCES BETWEEN THE MODELS. THE CHANCE
FOR THUNDERSTORMS CONTINUES DURING THE WORK WEEK AS THE UPPER LOW
CONTINUES TO SEND SHORT WAVES INTO THE AREA. IT WILL NOT BE RAINING
ALL OF THE TIME AND THERE MAY BE TIMES WHERE SOME LOCATIONS DO NOT
HAVE ANY PRECIPITATION DURING SOME PERIODS... BUT THERE IS AT LEAST
A SMALL CHANCE EVERY DAY. THE BEST CHANCES SHOULD BE DURING THE
AFTERNOON AND INTO THE OVERNIGHT HOURS.
SOME OF THE STORMS COULD BE SEVERE DURING THIS PERIOD. THE BEST
CHANCE FOR SEVERE WILL BE TUESDAY AND TUESDAY NIGHT WHEN THE MUCAPE
APPROACHES 2500 J/KG. THERE COULD BE SOME ISOLATED SEVERE AT OTHER
TIMES.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 650 PM CDT FRI MAY 31 2013
VFR CONDITIONS EXPECTED THROUGH 10Z...WITH MVFR CONDITIONS
FORECAST 10-16Z...AND VFR CONDITIONS 16Z ONWARD.
AN APPROACHING A MID LEVEL SHORT WAVE...PIVOTING AROUND THE
SOUTHERN PERIPHERY OF A MID LEVEL LOW OVER THE NORTHERN
PLAINS...WILL BRING INCREASING CLOUD COVER TO KGRI TONIGHT AND
INTO THE DAY SATURDAY. MULTIPLE SETS OF GUIDANCE SUGGEST AN MVFR
CEILING WILL BE REALIZED FOR A TIME SATURDAY MORNING AND GIVEN
THIS...OPTED TO GO WITH PREVAILING MVFR CONDITIONS 10-16Z.
ALTHOUGH THE CLOUD COVER SHOULD REMAIN INTACT THROUGH MUCH OF THE
DAY SATURDAY...INCREASING DIABATIC HEATING AND AN INCREASING
BOUNDARY LAYER HEIGHT SHOULD ALLOW FOR AN INCREASING CEILING
HEIGHT BY LATE MORNING SATURDAY...THUS THE VFR RESTORATION
FORECAST AT 16Z. MEASURABLE PRECIPITATION WILL BE POSSIBLE ACROSS
PORTIONS OF THE REGION TONIGHT...BUT THE MAJORITY OF GUIDANCE
SUGGESTS THIS PRECIPITATION WILL REMAIN WELL NORTH/NORTHEAST OF
KGRI. THE SURFACE WIND WILL REMAIN FROM THE NORTHWEST THROUGH THE
NEXT 24 HOURS...SUSTAINED AT AROUND 17KTS. GUSTS NEAR 34KTS WILL
REMAIN POSSIBLE UNTIL AROUND 02Z TONIGHT...WITH GUSTS AROUND 24KTS
THEN FORECAST 16Z ONWARD ON SATURDAY. VISIBILITY RESTRICTION IS
NOT EXPECTED AT KGRI THROUGH THE NEXT 24 HOURS.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...SALTZMAN
LONG TERM...JCB
AVIATION...BRYANT
AREA FORECAST DISCUSSION...UPDATED
NWS ALBUQUERQUE NM
1200 PM MDT THU MAY 30 2013
.AVIATION...
18Z TAF CYCLE
WITH A POTENT UPPER LEVEL JET STRETCHED OVER NORTHERN NEW
MEXICO...ANOTHER AFTERNOON OF GUSTY WEST TO NORTHWEST WINDS WILL
PREVAIL ACROSS THE FORECAST AREA...FAVORING THE NORTHERN HIGH
TERRAIN...ADJACENT EAST SLOPES...EASTERN HIGHLANDS AND NORTHEAST
PLAINS. SATELLITE WV IMAGERY DEPICTS MOUNTAIN WAVES IN THE
NORTHEAST THIRD OF THE FORECAST AREA. SURFACE WINDS WILL GUST TO
35-40KTS ACROSS THE NORTH AND KABQ WILL BE MONITORED FOR A POTENTIAL
AWW ISSUANCE...TAF IS CURRENTLY CARRYING GUSTS JUST BELOW
CRITERIA. BLOWING DUST COULD RESTRICT VISIBILITIES TO 3-5SM CENTRAL
AND EASTERN LOCATIONS. WINDS WILL GRADUALLY RELAX AFTER 03Z...AND
WILL START TO INCREASE AFTER 15Z ON FRIDAY WITH SOMEWHAT LOWER
MAGNITUDES THAN THOSE OF TODAY. WITH THE EXCEPTION OF AREAS IMPACTED
BY BLOWING DUST...VFR CONDITIONS EXPECTED ALL AREAS.
05
&&
.PREV DISCUSSION...325 AM MDT THU MAY 30 2013...
DRYLINE HAS SO FAR STAYED TO THE EAST OF NEW MEXICO THIS MORNING AND
ALTHOUGH IT/S FAIRLY CLOSE TO HOBBS DON/T EXPECT IT TO GET MUCH
FARTHER WEST IF AT ALL. IN THE NORTHEAST DEWPOINTS HAVE COME UP AS
THE SFC LOW SHIFTED INTO THE TX/OK PANHANDLES BUT THIS INCREASE
LIKELY WON/T LAST LONG WITH THE RUC FORECASTING A WEAK SFC LOW TO
REDEVELOP OVER SE CO BY MIDDAY. MODELS ALSO SHOW CURRENT BATCH OF
MID LEVEL MOISTURE EXITING BY MIDDAY. UPPER JET TO RETREAT NWD TODAY
BUT WILL BE STRETCHED OVER FAR NRN NM AND COLORADO...COMBINED WITH
THE SFC LOW PLACEMENT WILL HAVE LOW END WIND ADVY OVER SOME OF THE
NORTH CENTRAL/NORTHEAST SOUTH TO CLINES CORNERS.
DRY INTO FRIDAY NIGHT. ANOTHER WINDY DAY ON FRIDAY WITH CRITICAL
FIRE WX CONDITIONS POSSIBLE. ANOTHER BATCH OF MID LEVEL MOISTURE
PASSES OVERHEAD TONIGHT AND FRIDAY BUT ANYTHING MORE THAN A FEW
SPRINKLES OUT OF IT...IF THAT...WOULD BE A SURPRISE.
SURFACE FRONT PUSHES THROUGH FRIDAY NIGHT WITH THE BACK DOOR FRONT
INTO THE EAST SATURDAY. LOW LEVEL MOISTURE APPEARS TO MOVE IN FROM
THE SOUTH AND SOUTHEAST WITH INCREASING INSTAB SO WENT AHEAD AND
SPREAD SOME SMALL POPS FROM THE EAST SLOPES OF THE SOUTH CENTRAL
MOUNTAIN ACROSS CHAVES COUNTY AND NORTHEAST ALONG THE TX BORDER
SATURDAY AFTERNOON ALTHOUGH FOR NOW BEST CONFIDENCE IS IN THE
SOUTHEAST. ANOTHER BLOB OF MID LEVEL MOISTURE TO MIGRATE OVER THE
SOUTHERN HALF OF THE STATE AND COULD NOT RULE OUT A FEW SPRINKLES
UNDERNEATH IT...BUT LEFT MENTION OUT OF FCST FOR NOW. IN FACT THE
ADJMET GUIDANCE DOES PAINT SOME LOW POPS OVER THE SOUTHWEST MTS.
INCREASED POPS SOMEWHAT SUNDAY ESPECIALLY ALONG THE CENTRAL MT
CHAIN. LEFT THE MENTION OF DRY CONVECTION FROM THE RGV WWD ALTHOUGH
COULD BE A MIX WITH AT LEAST SOME MEAGER MEASURABLE PCPN DEPENDING
IF THE SURGE IS AS STRONG AS DEPICTED SO FAR. HOWEVER...MONDAY
STARTS TO DRY OUT AND TUESDAY EVEN MORE SO. REMOVED THE POPS IN THE
EAST FOR TUESDAY NIGHT...AND PROBABLY SHOULD HAVE FOR TUESDAY AS
WELL AS RIGHT NOW IT LOOKS DRY. ANOTHER BACKDOOR FRONT WEDNESDAY
LOOKS TO PUSH INTO THE RGV WEDNESDAY NIGHT...SO POPS/WX GRIDS FOR
MID TO LATE WEEK HAVE BEEN UPDATED.
.FIRE WEATHER...
...WIDESPREAD CRITICAL FIRE WEATHER CONDITIONS DUE TO STRONG WIND
AND LOW HUMIDITY FOR MUCH OF NORTHERN AND CENTRAL NEW MEXICO THROUGH
FRIDAY...
...DRY LIGHTNING THREAT INCREASING SUNDAY CENTRAL/WEST...
MOVING INTO DAY 2 OF A PROTRACTED CRITICAL FIRE WEATHER PATTERN THAT
WILL EXTEND THROUGH FRIDAY. THEREAFTER...FAR LESS WIND BUT GROWING
CONFIDENCE IN A SUBSTANTIAL WESTERLY PUSH OF LOWER LEVEL MOISTURE
THAT WILL RESULT IN A SIGNIFICANT DRY LIGHTNING THREAT FOR
CENTRAL/WESTERN AREAS BY SUNDAY.
SATURDAY LOOKS TO BE A CLASSIC TRANSITION DAY AS RICHER LOW LEVEL
MOISTURE INITIALLY MAKES A RETURN TO THE EC/SE PLAINS AS SURFACE
WINDS VEER TO SELY AND TAPS INTO A NOW SEMI-PERMANENT POOL OF
GULFMEX MOISTURE. POTENTIAL FOR SOME DRIER STORMS ALONG THE EAST
SLOPES OF THE CENTRAL/SC MOUNTAIN SATURDAY PM. HIGHER DEW POINT AIR
ALSO CREEPING NORTHWARD ALONG THE RGV AND THAT COUPLED WITH A SUBTLE
AND ALWAYS SNEAKY UPTICK IN MID-LEVEL MOISTURE AS THE UPPER RIDGE
EXPANDS/BUILDS NORTHWARD COULD RESULT IN AT LEAST AN ISOLATED DRY
LIGHTNING THREAT OVER THE WC/SW HIGHER TERRAIN AS EARLY AS SATURDAY
AFTERNOON OR EVENING. THIS WILL BE CLOSELY MONITORED.
EVEN THE SLIGHTEST UPTICK IN LOWER/MID LEVEL MOISTURE IN THE
PRESENCE OF VERY STEEP LAPSE RATES THAT ARE TYPICAL OF THE
DEVELOPING PATTERN THIS WEEKEND SEEMS TO RESULT IN MORE THAN
EXPECTED BUILDUPS/VIRGA AND DRY CG/S. WE SHALL SEE. SUNDAY
AFTERNOON/EVENING LOOKING TO BE THE MORE CRITICAL DAY WITH RESPECT
TO DRY LIGHTNING FOR THE WEST THOUGH MONDAY COULD BE FAIRLY ACTIVE
EAST OF THE DIVIDE TO THE EAST SLOPES OF THE CENTRAL MOUNTAIN
CHAIN AS DRIER AIR ADVANCES EASTWARD.
IN THE MEANTIME...LARGE-SCALE UPPER TROUGH SLOWLY PIVOTING NORTHEAST
FROM THE CENTRAL/NORTHERN ROCKIES EARLY THIS MORNING. BASE OF THE
TROUGH TRANSLATED EASTWARD OVER OUR AREA THIS PAST NIGHT AND PRESENT
INDICATIONS ARE THAT THE STRONGEST MID-LEVEL WINDS WILL PASS
OVERHEAD BEFORE MIDDAY. THAT SAID...AN ANOMALOUSLY STRONG UPPER
LEVEL JET ORIENTED NW TO SE FROM THE GREAT BASIN TO THE FOUR CORNERS
REGION WILL NOT SHIFT NORTHWARD APPRECIABLY TODAY. AS A
RESULT...WIND SPEEDS THOUGH A BIT LESS THAN YESTERDAY WILL STILL BE
SIGNIFICANT WITH FREQUENT GUSTS OF 35-40 MPH ACROSS THE NORTH.
SURFACE LOW NOT AS FAVORABLE EITHER. NO CHANGES TO THE FIRE
WEATHER WATCH FOR FRIDAY THOUGH BELT OF STRONGEST WINDS DO SHIFT
SOUTHWARD PER PREVIOUS FORECAST. VERY DEEP MIXING CONTINUES TODAY
BEFORE MAX MIXING HEIGHTS TREND DOWNWARD SLIGHTLY ON FRIDAY. LOWEST
RH VALUES CENTRAL VALLEY CORRIDOR AND IN THE EAST.
EXTENDED MODELS STILL TRENDING DRIER/BREEZIER EARLY NEXT WORK WEEK
FOLLOWING OUR LIGHTNING PERIOD. BACK TO VERY DEEP MIXING AND GUSTY
AFTERNOON/EVENING PERIODS THOUGH TOO EARLY TO GAUGE STRENGTH OF ANY
SUSTAINED WINDY PERIODS. KJ
&&
.ABQ WATCHES/WARNINGS/ADVISORIES...
RED FLAG WARNING UNTIL 8 PM MDT THIS EVENING FOR THE FOLLOWING
ZONES...NMZ101>104-106>108.
FIRE WEATHER WATCH FROM FRIDAY MORNING THROUGH FRIDAY EVENING FOR
THE FOLLOWING ZONES...NMZ101>108.
WIND ADVISORY UNTIL 9 PM MDT THIS EVENING FOR THE FOLLOWING ZONES...
NMZ510>516-523-527>529.
&&
$$
50
AREA FORECAST DISCUSSION...UPDATED
NWS ALBUQUERQUE NM
536 AM MDT THU MAY 30 2013
.AVIATION...
12Z TAF CYCLE
AREA TO REMAIN UNDER THE INFLUENCE OF A FAST WEST-NORTHWEST FLOW
ALOFT THROUGH AT LEAST 12Z FRI. AXIS OF STRONG UPPER JET LOCATED
JUST NORTH OF THE STATE BUT IN A FAVORABLE POSITION AND
ORIENTATION TO GENERATE MOUNTAIN WAVES AND ASSOCIATED IMPACTS OVER
THE NORTHERN MOUNTAINS AND ESPECIALLY THE SANGRE DE CRISTO AND
IMMEDIATE EAST SLOPES. SFC WINDS GUSTS FREQUENTLY IN THE 30-35 KT
RANGE EXPECTED FOR ALL TERMINAL SITES EXCEPT KROW WHERE SOMEWHAT
LIGHTER WIND CONDITIONS EXPECTED AS COMPARED TO CENTRAL AND
NORTHERN AREAS OF THE STATE. AREAS OF BLOWING DUST EXPECTED TO
RESULT IN REDUCED VSBY TO 5SM OR LESS AT TIMES...ESPECIALLY LOWER
ELEVATIONS CENTRAL AND EAST. SIGNIFICANT CLOUD COVER IS NOT
EXPECTED ALTHOUGH BRIEF BKN120 SKY CONDITIONS MAY BE ENCOUNTERED
ACROSS THE FAR NORTH. KJ
&&
.PREV DISCUSSION...325 AM MDT THU MAY 30 2013...
DRYLINE HAS SO FAR STAYED TO THE EAST OF NEW MEXICO THIS MORNING AND
ALTHOUGH IT/S FAIRLY CLOSE TO HOBBS DON/T EXPECT IT TO GET MUCH
FARTHER WEST IF AT ALL. IN THE NORTHEAST DEWPOINTS HAVE COME UP AS
THE SFC LOW SHIFTED INTO THE TX/OK PANHANDLES BUT THIS INCREASE
LIKELY WON/T LAST LONG WITH THE RUC FORECASTING A WEAK SFC LOW TO
REDEVELOP OVER SE CO BY MIDDAY. MODELS ALSO SHOW CURRENT BATCH OF
MID LEVEL MOISTURE EXITING BY MIDDAY. UPPER JET TO RETREAT NWD TODAY
BUT WILL BE STRETCHED OVER FAR NRN NM AND COLORADO...COMBINED WITH
THE SFC LOW PLACEMENT WILL HAVE LOW END WIND ADVY OVER SOME OF THE
NORTH CENTRAL/NORTHEAST SOUTH TO CLINES CORNERS.
DRY INTO FRIDAY NIGHT. ANOTHER WINDY DAY ON FRIDAY WITH CRITICAL
FIRE WX CONDITIONS POSSIBLE. ANOTHER BATCH OF MID LEVEL MOISTURE
PASSES OVERHEAD TONIGHT AND FRIDAY BUT ANYTHING MORE THAN A FEW
SPRINKLES OUT OF IT...IF THAT...WOULD BE A SURPRISE.
SURFACE FRONT PUSHES THROUGH FRIDAY NIGHT WITH THE BACK DOOR FRONT
INTO THE EAST SATURDAY. LOW LEVEL MOISTURE APPEARS TO MOVE IN FROM
THE SOUTH AND SOUTHEAST WITH INCREASING INSTAB SO WENT AHEAD AND
SPREAD SOME SMALL POPS FROM THE EAST SLOPES OF THE SOUTH CENTRAL
MOUNTAIN ACROSS CHAVES COUNTY AND NORTHEAST ALONG THE TX BORDER
SATURDAY AFTERNOON ALTHOUGH FOR NOW BEST CONFIDENCE IS IN THE
SOUTHEAST. ANOTHER BLOB OF MID LEVEL MOISTURE TO MIGRATE OVER THE
SOUTHERN HALF OF THE STATE AND COULD NOT RULE OUT A FEW SPRINKLES
UNDERNEATH IT...BUT LEFT MENTION OUT OF FCST FOR NOW. IN FACT THE
ADJMET GUIDANCE DOES PAINT SOME LOW POPS OVER THE SOUTHWEST MTS.
INCREASED POPS SOMEWHAT SUNDAY ESPECIALLY ALONG THE CENTRAL MT
CHAIN. LEFT THE MENTION OF DRY CONVECTION FROM THE RGV WWD ALTHOUGH
COULD BE A MIX WITH AT LEAST SOME MEAGER MEASURABLE PCPN DEPENDING
IF THE SURGE IS AS STRONG AS DEPICTED SO FAR. HOWEVER...MONDAY
STARTS TO DRY OUT AND TUESDAY EVEN MORE SO. REMOVED THE POPS IN THE
EAST FOR TUESDAY NIGHT...AND PROBABLY SHOULD HAVE FOR TUESDAY AS
WELL AS RIGHT NOW IT LOOKS DRY. ANOTHER BACKDOOR FRONT WEDNESDAY
LOOKS TO PUSH INTO THE RGV WEDNESDAY NIGHT...SO POPS/WX GRIDS FOR
MID TO LATE WEEK HAVE BEEN UPDATED.
.FIRE WEATHER...
...WIDESPREAD CRITICAL FIRE WEATHER CONDITIONS DUE TO STRONG WIND
AND LOW HUMIDITY FOR MUCH OF NORTHERN AND CENTRAL NEW MEXICO THROUGH
FRIDAY...
...DRY LIGHTNING THREAT INCREASING SUNDAY CENTRAL/WEST...
MOVING INTO DAY 2 OF A PROTRACTED CRITICAL FIRE WEATHER PATTERN THAT
WILL EXTEND THROUGH FRIDAY. THEREAFTER...FAR LESS WIND BUT GROWING
CONFIDENCE IN A SUBSTANTIAL WESTERLY PUSH OF LOWER LEVEL MOISTURE
THAT WILL RESULT IN A SIGNIFICANT DRY LIGHTNING THREAT FOR
CENTRAL/WESTERN AREAS BY SUNDAY.
SATURDAY LOOKS TO BE A CLASSIC TRANSITION DAY AS RICHER LOW LEVEL
MOISTURE INITIALLY MAKES A RETURN TO THE EC/SE PLAINS AS SURFACE
WINDS VEER TO SELY AND TAPS INTO A NOW SEMI-PERMANENT POOL OF
GULFMEX MOISTURE. POTENTIAL FOR SOME DRIER STORMS ALONG THE EAST
SLOPES OF THE CENTRAL/SC MOUNTAIN SATURDAY PM. HIGHER DEW POINT AIR
ALSO CREEPING NORTHWARD ALONG THE RGV AND THAT COUPLED WITH A SUBTLE
AND ALWAYS SNEAKY UPTICK IN MID-LEVEL MOISTURE AS THE UPPER RIDGE
EXPANDS/BUILDS NORTHWARD COULD RESULT IN AT LEAST AN ISOLATED DRY
LIGHTNING THREAT OVER THE WC/SW HIGHER TERRAIN AS EARLY AS SATURDAY
AFTERNOON OR EVENING. THIS WILL BE CLOSELY MONITORED.
EVEN THE SLIGHTEST UPTICK IN LOWER/MID LEVEL MOISTURE IN THE
PRESENCE OF VERY STEEP LAPSE RATES THAT ARE TYPICAL OF THE
DEVELOPING PATTERN THIS WEEKEND SEEMS TO RESULT IN MORE THAN
EXPECTED BUILDUPS/VIRGA AND DRY CG/S. WE SHALL SEE. SUNDAY
AFTERNOON/EVENING LOOKING TO BE THE MORE CRITICAL DAY WITH RESPECT
TO DRY LIGHTNING FOR THE WEST THOUGH MONDAY COULD BE FAIRLY ACTIVE
EAST OF THE DIVIDE TO THE EAST SLOPES OF THE CENTRAL MOUNTAIN
CHAIN AS DRIER AIR ADVANCES EASTWARD.
IN THE MEANTIME...LARGE-SCALE UPPER TROUGH SLOWLY PIVOTING NORTHEAST
FROM THE CENTRAL/NORTHERN ROCKIES EARLY THIS MORNING. BASE OF THE
TROUGH TRANSLATED EASTWARD OVER OUR AREA THIS PAST NIGHT AND PRESENT
INDICATIONS ARE THAT THE STRONGEST MID-LEVEL WINDS WILL PASS
OVERHEAD BEFORE MIDDAY. THAT SAID...AN ANOMALOUSLY STRONG UPPER
LEVEL JET ORIENTED NW TO SE FROM THE GREAT BASIN TO THE FOUR CORNERS
REGION WILL NOT SHIFT NORTHWARD APPRECIABLY TODAY. AS A
RESULT...WIND SPEEDS THOUGH A BIT LESS THAN YESTERDAY WILL STILL BE
SIGNIFICANT WITH FREQUENT GUSTS OF 35-40 MPH ACROSS THE NORTH.
SURFACE LOW NOT AS FAVORABLE EITHER. NO CHANGES TO THE FIRE
WEATHER WATCH FOR FRIDAY THOUGH BELT OF STRONGEST WINDS DO SHIFT
SOUTHWARD PER PREVIOUS FORECAST. VERY DEEP MIXING CONTINUES TODAY
BEFORE MAX MIXING HEIGHTS TREND DOWNWARD SLIGHTLY ON FRIDAY. LOWEST
RH VALUES CENTRAL VALLEY CORRIDOR AND IN THE EAST.
EXTENDED MODELS STILL TRENDING DRIER/BREEZIER EARLY NEXT WORK WEEK
FOLLOWING OUR LIGHTNING PERIOD. BACK TO VERY DEEP MIXING AND GUSTY
AFTERNOON/EVENING PERIODS THOUGH TOO EARLY TO GAUGE STRENGTH OF ANY
SUSTAINED WINDY PERIODS. KJ
&&
.ABQ WATCHES/WARNINGS/ADVISORIES...
RED FLAG WARNING FROM 11 AM THIS MORNING TO 8 PM MDT THIS EVENING
FOR THE FOLLOWING ZONES...NMZ101>104-106>108.
FIRE WEATHER WATCH FROM FRIDAY MORNING THROUGH FRIDAY EVENING FOR
THE FOLLOWING ZONES...NMZ101>108.
WIND ADVISORY FROM 10 AM THIS MORNING TO 9 PM MDT THIS EVENING FOR
THE FOLLOWING ZONES...NMZ510>516-523-527>529.
&&
$$
41
AREA FORECAST DISCUSSION
NWS ALBUQUERQUE NM
325 AM MDT THU MAY 30 2013
.DISCUSSION...
DRYLINE HAS SO FAR STAYED TO THE EAST OF NEW MEXICO THIS MORNING AND
ALTHOUGH IT/S FAIRLY CLOSE TO HOBBS DON/T EXPECT IT TO GET MUCH
FARTHER WEST IF AT ALL. IN THE NORTHEAST DEWPOINTS HAVE COME UP AS
THE SFC LOW SHIFTED INTO THE TX/OK PANHANDLES BUT THIS INCREASE
LIKELY WON/T LAST LONG WITH THE RUC FORECASTING A WEAK SFC LOW TO
REDEVELOP OVER SE CO BY MIDDAY. MODELS ALSO SHOW CURRENT BATCH OF
MID LEVEL MOISTURE EXITING BY MIDDAY. UPPER JET TO RETREAT NWD TODAY
BUT WILL BE STRETCHED OVER FAR NRN NM AND COLORADO...COMBINED WITH
THE SFC LOW PLACEMENT WILL HAVE LOW END WIND ADVY OVER SOME OF THE
NORTH CENTRAL/NORTHEAST SOUTH TO CLINES CORNERS.
DRY INTO FRIDAY NIGHT. ANOTHER WINDY DAY ON FRIDAY WITH CRITICAL
FIRE WX CONDITIONS POSSIBLE. ANOTHER BATCH OF MID LEVEL MOISTURE
PASSES OVERHEAD TONIGHT AND FRIDAY BUT ANYTHING MORE THAN A FEW
SPRINKLES OUT OF IT...IF THAT...WOULD BE A SURPRISE.
SURFACE FRONT PUSHES THROUGH FRIDAY NIGHT WITH THE BACK DOOR FRONT
INTO THE EAST SATURDAY. LOW LEVEL MOISTURE APPEARS TO MOVE IN FROM
THE SOUTH AND SOUTHEAST WITH INCREASING INSTAB SO WENT AHEAD AND
SPREAD SOME SMALL POPS FROM THE EAST SLOPES OF THE SOUTH CENTRAL
MOUNTAIN ACROSS CHAVES COUNTY AND NORTHEAST ALONG THE TX BORDER
SATURDAY AFTERNOON ALTHOUGH FOR NOW BEST CONFIDENCE IS IN THE
SOUTHEAST. ANOTHER BLOB OF MID LEVEL MOISTURE TO MIGRATE OVER THE
SOUTHERN HALF OF THE STATE AND COULD NOT RULE OUT A FEW SPRINKLES
UNDERNEATH IT...BUT LEFT MENTION OUT OF FCST FOR NOW. IN FACT THE
ADJMET GUIDANCE DOES PAINT SOME LOW POPS OVER THE SOUTHWEST MTS.
INCREASED POPS SOMEWHAT SUNDAY ESPECIALLY ALONG THE CENTRAL MT
CHAIN. LEFT THE MENTION OF DRY CONVECTION FROM THE RGV WWD ALTHOUGH
COULD BE A MIX WITH AT LEAST SOME MEAGER MEASURABLE PCPN DEPENDING
IF THE SURGE IS AS STRONG AS DEPICTED SO FAR. HOWEVER...MONDAY
STARTS TO DRY OUT AND TUESDAY EVEN MORE SO. REMOVED THE POPS IN THE
EAST FOR TUESDAY NIGHT...AND PROBABLY SHOULD HAVE FOR TUESDAY AS
WELL AS RIGHT NOW IT LOOKS DRY. ANOTHER BACKDOOR FRONT WEDNESDAY
LOOKS TO PUSH INTO THE RGV WEDNESDAY NIGHT...SO POPS/WX GRIDS FOR
MID TO LATE WEEK HAVE BEEN UPDATED.
&&
.FIRE WEATHER...
...WIDESPREAD CRITICAL FIRE WEATHER CONDITIONS DUE TO STRONG WIND
AND LOW HUMIDITY FOR MUCH OF NORTHERN AND CENTRAL NEW MEXICO THROUGH
FRIDAY...
...DRY LIGHTNING THREAT INCREASING SUNDAY CENTRAL/WEST...
MOVING INTO DAY 2 OF A PROTRACTED CRITICAL FIRE WEATHER PATTERN THAT
WILL EXTEND THROUGH FRIDAY. THEREAFTER...FAR LESS WIND BUT GROWING
CONFIDENCE IN A SUBSTANTIAL WESTERLY PUSH OF LOWER LEVEL MOISTURE
THAT WILL RESULT IN A SIGNIFICANT DRY LIGHTNING THREAT FOR
CENTRAL/WESTERN AREAS BY SUNDAY.
SATURDAY LOOKS TO BE A CLASSIC TRANSITION DAY AS RICHER LOW LEVEL
MOISTURE INITIALLY MAKES A RETURN TO THE EC/SE PLAINS AS SURFACE
WINDS VEER TO SELY AND TAPS INTO A NOW SEMI-PERMANENT POOL OF
GULFMEX MOISTURE. POTENTIAL FOR SOME DRIER STORMS ALONG THE EAST
SLOPES OF THE CENTRAL/SC MOUNTAIN SATURDAY PM. HIGHER DEW POINT AIR
ALSO CREEPING NORTHWARD ALONG THE RGV AND THAT COUPLED WITH A SUBTLE
AND ALWAYS SNEAKY UPTICK IN MID-LEVEL MOISTURE AS THE UPPER RIDGE
EXPANDS/BUILDS NORTHWARD COULD RESULT IN AT LEAST AN ISOLATED DRY
LIGHTNING THREAT OVER THE WC/SW HIGHER TERRAIN AS EARLY AS SATURDAY
AFTERNOON OR EVENING. THIS WILL BE CLOSELY MONITORED.
EVEN THE SLIGHTEST UPTICK IN LOWER/MID LEVEL MOISTURE IN THE
PRESENCE OF VERY STEEP LAPSE RATES THAT ARE TYPICAL OF THE
DEVELOPING PATTERN THIS WEEKEND SEEMS TO RESULT IN MORE THAN
EXPECTED BUILDUPS/VIRGA AND DRY CG/S. WE SHALL SEE. SUNDAY
AFTERNOON/EVENING LOOKING TO BE THE MORE CRITICAL DAY WITH RESPECT
TO DRY LIGHTNING THOUGH MONDAY COULD BE FAIRLY ACTIVE EAST OF THE
DIVIDE.
IN THE MEANTIME...LARGE-SCALE UPPER TROUGH SLOWLY PIVOTING NORTHEAST
FROM THE CENTRAL/NORTHERN ROCKIES EARLY THIS MORNING. BASE OF THE
TROUGH TRANSLATED EASTWARD OVER OUR AREA THIS PAST NIGHT AND PRESENT
INDICATIONS ARE THAT THE STRONGEST MID-LEVEL WINDS WILL PASS
OVERHEAD BEFORE MIDDAY. THAT SAID...AN ANOMALOUSLY STRONG UPPER
LEVEL JET ORIENTED NW TO SE FROM THE GREAT BASIN TO THE FOUR CORNERS
REGION WILL NOT SHIFT NORTHWARD APPRECIABLY TODAY. AS A
RESULT...WIND SPEEDS THOUGH A BIT LESS THAN YESTERDAY WILL STILL BE
SIGNIFICANT WITH FREQUENT GUSTS OF 35-40 MPH ACROSS THE NORTH.
SURFACE LOW NOT AS FAVORABLE EITHER. NO CHANGES TO THE FIRE
WEATHER WATCH FOR FRIDAY THOUGH BELT OF STRONGEST WINDS DO SHIFT
SOUTHWARD PER PREVIOUS FORECAST. VERY DEEP MIXING CONTINUES TODAY
BEFORE MAX MIXING HEIGHTS TREND DOWNWARD SLIGHTLY ON FRIDAY. LOWEST
RH VALUES CENTRAL VALLEY CORRIDOR AND IN THE EAST.
EXTENDED MODELS STILL TRENDING DRIER/BREEZIER EARLY NEXT WORK WEEK
FOLLOWING OUR LIGHTNING PERIOD. BACK TO VERY DEEP MIXING AND GUSTY
AFTERNOON/EVENING PERIODS THOUGH TOO EARLY TO GAUGE STRENGTH OF ANY
SUSTAINED WINDY PERIODS. KJ
&&
.AVIATION...
06Z TAF CYCLE
TROUGH ALOFT EXTENDING FROM NORTHERN ROCKIES SOUTHWARD ACROSS
EASTERN NM TO THE TX BIG BEND COUNTRY...AS SURFACE TROUGH EXTENDS
FROM CENTRAL NEBRASKA ACROSS THE TX PANHANDLE. CLOUD COVER AOA
BKN/OVC100 MOVING EAST ACROSS THE STATE ALONG INTERSTATE 40
CORRIDOR WILL DISSIPATE BY 12Z THU MORNING. GUSTY WEST WINDS
REDEVELOPING RAPIDLY FROM 14Z ONWARD ACROSS THE EAST SLOPES OF OF
THE CENTRAL MTS...AND THEN STATEWIDE BY 18Z. AREAS OF BLOWING DUST
WILL DROP VIZ TO 5SM OR LESS AT TIMES...ESPECIALLY OVER THE EASTERN
PLAINS.
SHY
&&
.PRELIMINARY POINT TEMPS/POPS...
FARMINGTON...................... 81 49 82 42 / 0 0 0 0
DULCE........................... 73 41 75 32 / 0 0 0 0
CUBA............................ 77 43 77 40 / 0 0 0 0
GALLUP.......................... 81 45 82 37 / 0 0 0 0
EL MORRO........................ 79 44 81 40 / 0 0 0 0
GRANTS.......................... 82 47 84 39 / 0 0 0 0
QUEMADO......................... 81 47 83 43 / 0 0 0 0
GLENWOOD........................ 85 49 87 57 / 0 0 0 0
CHAMA........................... 71 37 70 30 / 5 0 5 5
LOS ALAMOS...................... 80 45 81 41 / 0 0 0 0
PECOS........................... 78 47 80 44 / 0 0 0 0
CERRO/QUESTA.................... 73 38 74 32 / 0 0 0 0
RED RIVER....................... 64 36 63 36 / 0 0 0 0
ANGEL FIRE...................... 69 38 71 34 / 0 0 0 0
TAOS............................ 75 40 77 34 / 0 0 0 0
MORA............................ 75 42 78 39 / 0 0 0 0
ESPANOLA........................ 83 45 84 45 / 0 0 0 0
SANTA FE........................ 80 45 80 43 / 0 0 0 0
SANTA FE AIRPORT................ 82 49 84 45 / 0 0 0 0
ALBUQUERQUE FOOTHILLS........... 83 56 85 50 / 0 0 0 0
ALBUQUERQUE HEIGHTS............. 85 60 88 56 / 0 0 0 0
ALBUQUERQUE VALLEY.............. 86 54 90 56 / 0 0 0 0
ALBUQUERQUE WEST MESA........... 86 58 88 54 / 0 0 0 0
LOS LUNAS....................... 88 60 91 56 / 0 0 0 0
RIO RANCHO...................... 85 58 87 54 / 0 0 0 0
SOCORRO......................... 90 62 94 59 / 0 0 0 0
SANDIA PARK/CEDAR CREST......... 82 51 83 49 / 0 0 0 0
TIJERAS......................... 83 55 85 48 / 0 0 0 0
MORIARTY/ESTANCIA............... 82 50 84 47 / 0 0 0 0
CLINES CORNERS.................. 81 51 80 47 / 0 0 0 0
GRAN QUIVIRA.................... 84 53 85 50 / 0 0 0 0
CARRIZOZO....................... 84 59 87 56 / 0 0 0 0
RUIDOSO......................... 76 57 80 57 / 0 0 0 0
CAPULIN......................... 80 48 82 40 / 0 0 0 5
RATON........................... 81 44 84 40 / 0 0 0 5
SPRINGER........................ 82 43 84 40 / 0 0 0 0
LAS VEGAS....................... 80 48 82 41 / 0 0 0 0
CLAYTON......................... 87 52 86 48 / 0 0 0 5
ROY............................. 84 51 85 46 / 0 0 0 5
CONCHAS......................... 90 53 91 52 / 0 0 0 0
SANTA ROSA...................... 91 54 92 52 / 0 0 0 0
TUCUMCARI....................... 95 55 95 53 / 0 0 0 5
CLOVIS.......................... 92 57 94 56 / 0 0 0 5
PORTALES........................ 94 57 95 56 / 0 0 0 5
FORT SUMNER..................... 94 59 96 55 / 0 0 0 0
ROSWELL......................... 96 64 99 62 / 0 0 0 0
PICACHO......................... 89 63 92 59 / 0 0 0 0
ELK............................. 84 62 88 58 / 0 0 0 0
&&
.ABQ WATCHES/WARNINGS/ADVISORIES...
RED FLAG WARNING FROM 11 AM THIS MORNING TO 8 PM MDT THIS EVENING
FOR THE FOLLOWING ZONES...NMZ101>104-106>108.
FIRE WEATHER WATCH FROM FRIDAY MORNING THROUGH FRIDAY EVENING FOR
THE FOLLOWING ZONES...NMZ101>108.
WIND ADVISORY FROM 10 AM THIS MORNING TO 9 PM MDT THIS EVENING FOR
THE FOLLOWING ZONES...NMZ510>516-523-527>529.
&&
$$
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
923 PM EDT FRI MAY 31 2013
.SYNOPSIS...
VERY WARM WEATHER WILL CONTINUE THROUGH THE WEEKEND. MUCH OF THE
TIME SHOULD BE RAIN-FREE THROUGH SATURDAY...WITH JUST SOME HIT AND
MISS SHOWERS AND THUNDERSTORMS POSSIBLE SATURDAY AFTERNOON AND
EVENING. A BETTER CHANCE FOR SHOWERS AND STORMS WILL EXIST
SUNDAY...AS A COLD FRONT NEARS THE REGION FROM THE WEST. MUCH
COOLER TEMPERATURES WILL FOLLOW THIS FRONT EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
820 PM UPDATE...
THUNDERSTORM ACTIVITY CONTINUES ALONG LAKE ERIE UNDER THE
INFLUENCE OF A NORTHWARD MOVING WAVE. THE LATEST HRRR FORECASTS
SOME OF THE SWRN NY ACTIVITY TO BRUSH AGAINST OUR WESTERN FA
BORDERS BETWEEN 7Z-9Z. HAVE ADDED ISOLATED CONVECTION TO THE
WESTERN GRIDS FOR EARLY SATURDAY MORNING.
420 PM UPDATE... ISOLD TSRA HAVE FIRED OVER OUR SERN ZNS LATE THIS
AFTN...IN RESPONSE TO A PASSING UPR-LVL WAVE. THIS ACTIVITY SHOULD
QUICKLY DIE OUT EARLY THIS EVE...AS FORCING WANES...AND THE AMS
STABILIZES DIURNALLY.
LTR TNT/TWDS DAYBREAK...THE REMNANTS OF CONVECTIVE ACTIVITY WELL
TO OUR W ATTM ACRS SRN ONT/LK ERIE COULD APPROACH OUR FAR NRN/WRN
ZNS. IN GENERAL...THIS PCPN SHOULD BE IN A WEAKENED PHASE BY THAT
TIME...AS IT WILL HAVE WELL OUTRUN ITS MAIN UPR-LVL SUPPORT. WE
HAVE ISOLD-SCTD POPS ACRS THE FINGER LKS/MOHAWK VLY/SRN TUG HILL
ZNS TO COVER THIS POTENTIAL.
DRY WX FORESEEN FROM THE TWIN TIERS SWD OVERNIGHT...WITH VERY
PATCHY FOG/HZ PSBL.
&&
.SHORT TERM /6 AM SATURDAY MORNING THROUGH MONDAY/...
430 PM UPDATE... ALTHOUGH WE`LL REMAIN UNDER A SYNOPTIC-SCALE UPR
RIDGE SAT...WE MAY SEE SOME HGT FALLS AFTER 18Z...SPCLY NRN/WRN
AREAS. THIS...COMBINED WITH A FAST MOVG UPR IMPULSE BRUSHING
UPSTATE NY...COULD SPARK SOME DIURNALLY ENHANCED SHRA/TSRA. THE
BEST CHC (SCTD VERBIAGE) SHOULD BE IN OUR NRN/WRN ZNS...WITH MORE
ISOLD COVERAGE ELSEWHERE.
SAT NGT...REMNANT CONVECTION FROM THE DAYTIME HRS SHOULD WANE DURG
THE EVE...LEADING TO A RELATIVE LULL FOR MOST OF THE NGT. TWDS SUN
AM...AS A MUCH BETTER DEFINED UPR-LVL TROUGH SWINGS TWDS SRN
ONT/LK ONT...WE COULD SEE A RENEWED AREA OF SHRA/TSRA. THUS...WE
INCREASE POPS INTO THE LIKELY/NUM RANGES BY THIS TIME...AGN MAINLY
NRN/WRN PTNS OF THE FA.
SUN SEEMS A BIT COMPLICATED FROM THIS EARLY VANTAGE PT...AS ONE
WELL DEFINED UPR WV (JUST ALLUDED TO) SHOULD SWING BY TO OUR N
DURG THE AM/MIDDAY HRS...WITH PERHAPS A DECREASE IN MID TO UPR-LVL
FORCING FOR CNY/NE PA THEREAFTER. THE NAM SEEMS MOST BULLISH ON
THIS SCENARIO...SHOWING A DVLPG MID-LVL CAP SUN AFTN/EVE...LIKELY
DUE TO DVM/COMPRESSIONAL WARMING AT THAT LVL BEHIND THE WV...AND
WITH DETERIORATING UPR JET DYNAMICS. THE GFS...HOWEVER...IS A BIT
SLOWER WITH THE UPR WV...AND ALSO SHOWS A BETTER DEFINED PV TAIL
TO THE S THROUGH OUR FA SUN AFTN...JUST IN ADVANCE OF THE SFC
FRNT. SFC COLD FRNTL TIMING SEEMS OPTIMAL FOR TSRA DVLPMT...WITH
FROPA EXPECTED EARLY IN THE EVE...HOWEVER MID TO UPR-LVL FORCING SEEMS
LIKE THE MOST QUESTIONABLE ASPECT. FOR NOW...WE FELT IT WAS PRUDENT TO
CONTINUE TO MENTION PSBL SVR TSRA/HVY RAINFALL ON SUN...WITH MODEL
DIFFS EVIDENT...AND SMALLER-SCALE DETAILS (NOT TYPICALLY WELL
RESOLVED THIS FAR OUT) LIKELY TO MAKE A BIG DIFFERENCE IN HOW
THINGS TRANSPIRE ON SUN. AT ANY RATE...WE FELT COMFORTABLE
CONTINUING LIKELY/NUM POPS SUN AFTN INTO THE EVE PD.
THE COLD FRNT SHOULD SLOWLY MAKE ITS WAY THROUGH THE RGN BY LTR
SUN NGT...WITH COOLER TEMPS TO FOLLOW ON MON.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
330 PM UPDATE...
A COOLER BUT VERY QUIET LONG TERM FORECAST EXPECTED WITH THE NEXT
SHOT AT RAIN HOLDING OFF UNTIL THE END OF NEXT WEEK. WE HAVE A
DECENT SHORT WAVE MOVING THROUGH AROUND 12Z TUESDAY...BUT THE BEST
MOISTURE AND LIFT REMAIN WELL TO OUR NORTH NEAR A CLOSED LOW OVER
EASTERN QUEBEC. A SLIGHT INCREASE IN CLOUD COVER IS POSSIBLE OVER
THE FAR NORTH BUT WILL CONTINUE A DRY FORECAST. AFTER THAT TIME
HEIGHTS BUILD WITH AN H5 RIDGE CRESTING OVERHEAD BY WEDNESDAY
NIGHT. TEMPS WILL MODERATE DURING THIS TIME WITH DRY WEATHER
THROUGH MOST OF THE AREA THURSDAY. BY THURSDAY NIGHT INTO FRIDAY
AS OUR FLOW TURNS MORE INTO THE SOUTHWEST...BOTH THE EURO AND GFS
SHOW A FRONTAL BOUNDARY MOVING TOWARD OUR AREA. THE EURO WOULD
KEEP IT WEST OF US THROUGH THE PERIOD WHILE THE GFS INTRODUCES
PRECIP MAINLY OVER THE WESTERN HALF OF THE CWA. CHANCE POPS FROM
WPC GUIDANCE LOOK GOOD THIS FAR OUT AND WILL FOLLOW.
&&
.AVIATION /02Z SATURDAY THROUGH WEDNESDAY/...
MAINLY CLR SKIES THIS EVENING WITH VFR CONDS. LGT WINDS AND UPR
50S TO LWR 60S DEW PTS WILL ALLOW DRAINAGE AND VLY FOG TO
DVLP...WITH ELM LIKELY GOING IFR LATE. OTRW...VFR CONDS WILL
PREVAIL OVRNGT INTO SAT. LTR SAT...APRCHG UPR SYSTEM AND SFC COLD
FNT WILL INCH CONV INTO THE REGION IN THE LAST FEW HRS OF THE TAF
PD. THIS WILL BRING PSBL MVFR CONDS WITH THE CELLS.
OUTLOOK...
SAT NIGHT/SUN...POTENTIAL FOR MVFR IN SHRA/TSRA.
MON/TUE...VFR EXCEPT POSSIBLE LINGERING MVFR FROM -SHRA EARLY MON.
WED...VFR.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...MLJ
NEAR TERM...DJP/MLJ
SHORT TERM...MLJ
LONG TERM...HEDEN
AVIATION...DGM/HEDEN
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
1257 PM CDT THU MAY 30 2013
.UPDATE...
ISSUED AT 1256 PM CDT THU MAY 30 2013
EARLY AFTERNOON UPDATE FOCUSES ON FINE TUNING POP TRENDS FOR
MAINLY THE SOUTH...WHERE THERE HAS BEEN ONLY ISOLATED SHOWERS
THROUGH THE DAY AFTER RECEIVING 3 TO 5 INCHES OVERNIGHT. SKIES ARE
CLEARING IN THE REGION...AND THEREFORE LIKING THE NAM SOLUTION
WHICH IS SLIGHTLY MORE UNSTABLE FOR LATE THIS AFTN INTO THE
EVENING. STILL THINK THERE IS A GOOD CHANCE FOR SCATTERED TSTMS IN
THE 21Z TO 03Z TIMEFRAME AND WILL MAINTAIN 30 TO 40 POPS. ALSO
UPDATED FOR NEW AVIATION DISCUSSION.
UPDATE ISSUED AT 1000 AM CDT THU MAY 30 2013
MORNING UPDATE FOCUSES ON FLOODING IN CLAY COUNTY MINNESOTA AND
POP TRENDS. RADAR CONTINUES TO SHOW A BAND OF SHOWERS ACROSS
NORTHWESTERN ZONES. INCREASED POPS IN THIS REGION AND DECREASED
POPS ACROSS THE SOUTHERN HALF OF THE CWA. HRRR DOES SHOW
REDEVELOPMENT OVER SOUTHEASTERN ZONES SO MAINTAINED
LIKELIES...HOWEVER WENT DOWN TO 30 POPS FOR SOUTHEASTERN ND AND
SOUTHERN VALLEY. WILL WAIT TO FURTHER ASSESS 12Z RUN BEFORE
CHANGING ANYTHING BEYOND 00Z FRIDAY. REPORTS OF FIVE TO SEVEN
INCHES ARE COMING IN ALONG THE BUFFALO RIVER BASIN TO INCLUDE THE
CITIES OF AVERILL AND DILWORTH. WILL EXTEND WARNING AREA IN TIME
BUT CHOP OFF CASS COUNTY AND NORMAN COUNTY...WHERE RADAR ESTIMATES
ARE ABOUT FOUR INCHES OR LESS WITH NO REPORTS OF OVERLAND FLOODING
FROM THOSE COUNTY MANAGERS.
&&
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 355 AM CDT THU MAY 30 2013
THE MAIN CHALLENGE WILL BE SHOWER AND THUNDERSTORM CHANCES INTO
FRIDAY AND HEAVY RAIN POTENTIAL. THE MODELS ARE IN GOOD OVERALL
AGREEMENT BUT NOT PICKING UP TOO WELL ON MESOSCALE FEATURES.
FOR TODAY AND TONIGHT...EXPECT SHOWERS AND STORMS TO LIFT TO THE NORTH
AND LIKELY BECOME MORE FOCUSED IN THE NORTHERN AREAS. THERE WILL
BE A CHANCE FOR LOCALLY HEAVY RAINFALL NEAR ANY STORMS...GIVEN
PWATS OVER 1.5 INCHES. THERE COULD BE SOME STRONGER STORMS THIS
AFTERNOON IF SFC HEATING OCCURS...BUT I AGREE WITH SPC IN KEEPING
JUST 5% PROBS FOR HAIL/WIND AND NO SLIGHT RISK AT THIS TIME. THINK
THE MAIN ISSUE COULD BE HEAVY RAIN IF TRAINING ECHOES DEVELOPS.
HARD TO PINPOINT WHERE THIS MAY OCCUR...SO NO FLOOD HEADLINES
PLANNED...ALTHOUGH THERE COULD BE MORE FLOODING ISSUES NEAR
PERSISTENT HEAVY RAIN TODAY AND TONIGHT.
FOR FRIDAY...THE UPPER LOW WILL SLOWLY MOVE INTO THE AREA FROM THE
WEST AND EXPECT MORE WRAPAROUND SHOWERS AND SOME THUNDER. AGAIN
LOCALLY HEAVY RAINFALL IS POSSIBLE NEAR STRONGER SHOWERS AND
STORMS. IT WILL BE COOLER THAN TODAY WITH WINDS SHIFTING TO THE
NORTH BY AFTERNOON IN ALL BUT THE SOUTH AND EASTERN AREAS.
.LONG TERM...(FRIDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 355 AM CDT THU MAY 30 2013
FOR FRI NIGHT INTO SAT...WRAPAROUND SHOWERS WILL CONTINUE BEFORE
IT DRIES OUT BY SAT AFTERNOON.
FOR SUNDAY THROUGH WEDNESDAY...EXPECT A LOW AMPLITUDE LONG WAVE
TROUGH OVER THE NORTHERN PLAINS TO SHIFT EAST. ECMWF AND GFS
GENERALLY AGREE TIMING WISE HOWEVER THE GFS IS A HIGHER AMPLITUDE
SOLUTION COMPARED TO THE ECMWF. WILL BLEND THE MODELS.
ECMWF HAS SLOWED DOWN FROM MODEL RUN TO MODEL RUN WHILE THE GFS HAS
SHIFTED PRECIP SOUTH WITH EACH RUN. WILL SLOW DOWN PRECIP FOR TUE AND
DECREASE POPS A BIT FOR MON AND MON NIGHT.
LITTLE CHANGE TO TEMPS FOR SUN THROUGH TUE. WED HIGH TEMP WAS
INCREASED BY 3 DEGREES IN THE NORTHWEST ZONES AND A DEGREE OR TWO
LOWER IN THE SOUTHERN ZONES.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1256 PM CDT THU MAY 30 2013
COMPLEX SITUATION AS AN UPPER LOW MOVES ACROSS THE NORTHERN PLAINS.
MOST LOCATIONS HAVE HAD MVFR CEILINGS WITH SCATTERED SHOWERS MOVING
ACROSS THE FORECAST AREA. KEPT MOSTLY MVFR CEILINGS WITH VCSH OR
-SHRA BUT THERE COULD BE SOME IMPROVEMENTS TO VFR OR DROPS TO IFR AT
TIMES. VIS SHOULD ONLY BE LIMITED WHEN SHOWERS MOVE OVER. SOME
THUNDERSTORMS AND CB ARE ALSO POSSIBLE...MAINLY IN THE KFAR AREA
DURING THE LATE AFTERNOON AND EVENING. WINDS ACROSS THE
NORTHWESTERN FORECAST AREA WILL SHIFT TO THE NORTH AS THE SFC LOW
BEGINS TO MOVE EAST AND A COLD FRONT MOVES INTO THE AREA. AHEAD OF
THE FRONT WINDS WILL REMAIN OUT OF THE SOUTH AND EAST. THINK THAT
MOST LOCATIONS WILL BE MVFR OR IFR CEILINGS AND MVFR VIS WITH
SCATTERED RAIN SHOWERS THROUGH THE EARLY MORNING HOURS. SOME
IMPROVEMENT IS POSSIBLE TOWARDS THE END OF THE TAF PERIOD.
&&
.HYDROLOGY...
ISSUED AT 1256 PM CDT THU MAY 30 2013
A BAND OF HEAVY RAIN FELL OVERNIGHT FROM FARGO THROUGH NORTHEASTERN
CLAY COUNTY...WITH AMOUNTS GENERALLY RANGING FROM TWO TO FOUR
INCHES. REPORTS OF OVERLAND FLOODING IN THE VICINITY OF AVERILL AND
DILWORTH HAVE PROMPTED AN EXTENSION OF THE AREAL FLOOD WARNING
THROUGH 03Z FRIDAY. CASS COUNTY ND AND NORMAN COUNTY MN WERE REMOVED
FROM WARNING AREA AS THE THREAT OF OVERLAND FLOODING HAS ENDED IN
THOSE AREAS. OTHERWISE...FLOWS FROM THE HEAVY RAIN OVERLAND AND INTO
DITCHES AND STREAMS HAS WORKED ITS WAY INTO THE BUFFALO AND WILD
RICE RIVERS...PROMPTING A NEW RIVER FLOOD WARNING FOR THE WILD RICE
RIVER AT HENDRUM AFFECTING NORMAN COUNTY AND A CONTINUATION OF THE
RIVER FLOOD WARNING AT THE BUFFALO RIVER NEAR DILWORTH AFFECTING
CLAY COUNTY. SOME POINTS ON THE MAINSTEM RED RIVER AND A FEW
TRIBUTARIES ARE PROGGED TO RISE TO ACTION STAGE...AND ANTICIPATED
PCPN IS NOT EXPECTED TO AFFECT FORECAST LEVELS FOR NOW.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...SPEICHER
SHORT TERM...DK
LONG TERM...HOPPES/DK
AVIATION...JR
HYDROLOGY...HOPKINS
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
1000 AM CDT THU MAY 30 2013
.UPDATE...
ISSUED AT 1000 AM CDT THU MAY 30 2013
MORNING UPDATE FOCUSES ON FLOODING IN CLAY COUNTY MINNESOTA AND
POP TRENDS. RADAR CONTINUES TO SHOW A BAND OF SHOWERS ACROSS
NORTHWESTERN ZONES. INCREASED POPS IN THIS REGION AND DECREASED
POPS ACROSS THE SOUTHERN HALF OF THE CWA. HRRR DOES SHOW
REDEVELOPMENT OVER SOUTHEASTERN ZONES SO MAINTAINED
LIKELIES...HOWEVER WENT DOWN TO 30 POPS FOR SOUTHEASTERN ND AND
SOUTHERN VALLEY. WILL WAIT TO FURTHER ASSESS 12Z RUN BEFORE
CHANGING ANYTHING BEYOND 00Z FRIDAY. REPORTS OF FIVE TO SEVEN
INCHES ARE COMING IN ALONG THE BUFFALO RIVER BASIN TO INCLUDE THE
CITIES OF AVERILL AND DILWORTH. WILL EXTEND WARNING AREA IN TIME
BUT CHOP OFF CASS COUNTY AND NORMAN COUNTY...WHERE RADAR ESTIMATES
ARE ABOUT FOUR INCHES OR LESS WITH NO REPORTS OF OVERLAND FLOODING
FROM THOSE COUNTY MANAGERS.
&&
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 355 AM CDT THU MAY 30 2013
THE MAIN CHALLENGE WILL BE SHOWER AND THUNDERSTORM CHANCES INTO
FRIDAY AND HEAVY RAIN POTENTIAL. THE MODELS ARE IN GOOD OVERALL
AGREEMENT BUT NOT PICKING UP TOO WELL ON MESOSCALE FEATURES.
FOR TODAY AND TONIGHT...EXPECT SHOWERS AND STORMS TO LIFT TO THE NORTH
AND LIKELY BECOME MORE FOCUSED IN THE NORTHERN AREAS. THERE WILL
BE A CHANCE FOR LOCALLY HEAVY RAINFALL NEAR ANY STORMS...GIVEN
PWATS OVER 1.5 INCHES. THERE COULD BE SOME STRONGER STORMS THIS
AFTERNOON IF SFC HEATING OCCURS...BUT I AGREE WITH SPC IN KEEPING
JUST 5% PROBS FOR HAIL/WIND AND NO SLIGHT RISK AT THIS TIME. THINK
THE MAIN ISSUE COULD BE HEAVY RAIN IF TRAINING ECHOES DEVELOPS.
HARD TO PINPOINT WHERE THIS MAY OCCUR...SO NO FLOOD HEADLINES
PLANNED...ALTHOUGH THERE COULD BE MORE FLOODING ISSUES NEAR
PERSISTENT HEAVY RAIN TODAY AND TONIGHT.
FOR FRIDAY...THE UPPER LOW WILL SLOWLY MOVE INTO THE AREA FROM THE
WEST AND EXPECT MORE WRAPAROUND SHOWERS AND SOME THUNDER. AGAIN
LOCALLY HEAVY RAINFALL IS POSSIBLE NEAR STRONGER SHOWERS AND
STORMS. IT WILL BE COOLER THAN TODAY WITH WINDS SHIFTING TO THE
NORTH BY AFTERNOON IN ALL BUT THE SOUTH AND EASTERN AREAS.
.LONG TERM...(FRIDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 355 AM CDT THU MAY 30 2013
FOR FRI NIGHT INTO SAT...WRAPAROUND SHOWERS WILL CONTINUE BEFORE
IT DRIES OUT BY SAT AFTERNOON.
FOR SUNDAY THROUGH WEDNESDAY...EXPECT A LOW AMPLITUDE LONG WAVE
TROUGH OVER THE NORTHERN PLAINS TO SHIFT EAST. ECMWF AND GFS
GENERALLY AGREE TIMING WISE HOWEVER THE GFS IS A HIGHER AMPLITUDE
SOLUTION COMPARED TO THE ECMWF. WILL BLEND THE MODELS.
ECMWF HAS SLOWED DOWN FROM MODEL RUN TO MODEL RUN WHILE THE GFS HAS
SHIFTED PRECIP SOUTH WITH EACH RUN. WILL SLOW DOWN PRECIP FOR TUE AND
DECREASE POPS A BIT FOR MON AND MON NIGHT.
LITTLE CHANGE TO TEMPS FOR SUN THROUGH TUE. WED HIGH TEMP WAS
INCREASED BY 3 DEGREES IN THE NORTHWEST ZONES AND A DEGREE OR TWO
LOWER IN THE SOUTHERN ZONES.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 1000 AM CDT THU MAY 30 2013
IFR TO MVFR CIGS WILL CONTINUE ACROSS MOST OF THE REGION THIS
MORNING...WITH SLOW IMPROVEMENT TO MVFR OR VFR BY AFTERNOON. EXPECT
A SHOWER OR STORM NEARLY ANYTIME THROUGH THE PERIOD...BUT TRIED TO
INDICATE THE BEST POTENTIAL FOR RAIN.
&&
.HYDROLOGY...
ISSUED AT 355 AM CDT THU MAY 30 2013
A BAND OF HEAVY RAIN FELL OVERNIGHT FROM FARGO THROUGH
NORTHEASTERN CLAY COUNTY. THIS HAS PROMPTED AN AREAL FLOOD WARNING
FOR THE REGION. REPORTS OF OVERLAND FLOODING IN THE VICINITY OF
AVERILL AND DILWORTH HAVE PROMPTED AN EXTENSION OF WARNING THROUGH
03Z FRIDAY. HAVE REMOVED CASS COUNTY ND AND NORMAN COUNTY MN FROM
WARNING AREA.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...SPEICHER
SHORT TERM...DK
LONG TERM...HOPPES/DK
AVIATION...JR
HYDROLOGY...DK/SPEICHER
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1232 AM CDT THU MAY 30 2013
.UPDATE...
ISSUED AT 1231 AM CDT THU MAY 30 2013
CURRENT FORECAST IS ON TRACK WITH HOURLY GRIDS CLOSELY MATCHING
LATEST OBSERVATIONS. WATER VAPOR SHOWS NEGATIVELY TILTED TROUGH
EXTENDING FROM CENTRAL MONTANA TO NEBRASKA/SOUTH DAKOTA CONTINUING
TO PIVOT TOWARD NORTH DAKOTA. ASSOCIATED SURFACE LOW IS LOCATED
OVER SOUTH DAKOTA. RELATIVELY MOIST DEWPOINTS IN THE LOW 60S ARE
ADVECTING INTO SOUTHEAST NORTH DAKOTA WITH WARM FRONT GENERALLY IN
THE VICINITY OF THE ND/SD BORDER. SHOWERS AND ISOLATED/SCATTERED
THUNDERSTORMS HAVE EXPANDED THE PAST COUPLE HOURS ACROSS SOUTH
CENTRAL AND SOUTHEAST ND WITH THIS AREA MOVING TO THE
NORTHWEST...JUST ABOUT AT BISMARCK AT THIS TIME. MODELS ARE IN
DECENT AGREEMENT WITH SOME SLIGHT DIFFERENCES IN SURFACE LOW
LOCATION. UPPER TROUGH REFERENCED ABOVE WILL CUT OFF THURSDAY
MORNING RESULTING IN SURFACE LOW MOVING TO NORTH DAKOTA ON
THURSDAY AND REMAINING NEARLY STATIONARY THROUGH THURSDAY NIGHT.
UPDATE ISSUED AT 938 PM CDT WED MAY 29 2013
ONCE AGAIN...GIVEN THE LATEST RADAR TRENDS...THE 18 AND INCOMING
00 UTC DETERMINISTIC GUIDANCE AND 01 UTC RAP/HRRR SIMULATED
REFLECTIVITY FORECASTS...REDUCED POPS THROUGH 06 UTC FOR MUCH OF
THE AREA UNTIL THE ARRIVAL OF GREATER UPPER LEVEL FORCING AS
CONVECTION ACROSS SOUTH DAKOTA THROUGH NEBRASKA MAY ALSO BE
DISRUPTING MOISTURE TRANSPORT INTO NORTH DAKOTA. DO NOT ANTICIPATE
SEVERE WEATHER TONIGHT ACROSS WESTERN AND CENTRAL NORTH
DAKOTA...WITH A POTENTIAL RETURN OF THE THREAT TOMORROW AFTERNOON
AND EVENING DEPENDENT UPON HOW MUCH CLEARING/INSOLATION IS
ACHIEVED IN THE WARM SECTOR OF THE SURFACE LOW ACROSS SOUTH
CENTRAL NORTH DAKOTA.
UPDATE ISSUED AT 720 PM CDT WED MAY 29 2013
THE BIGGEST CHANGE WITH THIS UPDATE WAS TO REDUCE POPS...ESPECIALLY
ALONG AND NORTH OF US HIGHWAY 2...GIVEN THE LATEST RADAR TRENDS
AND THE 21 UTC HRRR SIMULATED REFLECTIVITY WHICH HAS MAINTAINED
CONTINUITY WITH PREVIOUS RUNS WHICH KEEP MUCH OF NORTHERN NORTH DAKOTA
PRECIPITATION FREE THROUGH AT LEAST 06 UTC. GIVEN THE MARGINAL
INSTABILITY AND SHEAR...THE SMALL WINDOW FOR SEVERE HAIL AND/OR
WINDS ACROSS THE JAMES RIVER VALLEY APPEARS TO BE QUICKLY CLOSING
AND WILL FOCUS ON HEAVY RAIN MONITORING OVER THE SATURATED AREAS
OF SOUTHERN NORTH DAKOTA.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 405 PM CDT WED MAY 29 2013
MAIN PROBLEM IN THE SHORT TERM PERIOD WILL BE PRECIPITATION
AMOUNTS...PLACEMENT AND TIMING.
CURRENTLY...SURFACE LOW PRESSURE OVER THE CENTRAL PLAINS WITH A
WARM FRONT EXTENDING INTO EASTERN SOUTH DAKOTA AND SOUTHERN
MINNESOTA. STRONG NEGATIVELY TILTED UPPER LEVEL TROUGH FROM THE
NORTHWEST U.S. INTO THE CENTRAL ROCKIES. CURRENT CONVECTION IN OUR
AREA IS LINING UP WITH THE THE STRONG WARM ADVECTION OVER THE
EASTERN DAKOTAS INTO MINNESOTA...AS WELL AS STRONG UPPER LEVEL
DIVERGENCE OVER EASTERN MONTANA.
TONIGHT...THE UPPER LEVEL WAVE WILL LIFT NORTHWARD INTO THE
NORTHERN HIGH PLAINS WITH THE SURFACE LOW TRACKING NORTH THROUGH
SOUTH DAKOTA. THIS WILL BRING INCREASING SHOWERS AND POSSIBLY SOME
THUNDERSTORMS TO WESTERN AND CENTRAL NORTH DAKOTA. ALTHOUGH WE DO
THINK MOST AREAS WILL RECEIVE PRECIPITATION...WE HAVE CONTINUED
THE TREND OF DELAYING THE ONSET...AND CUTTING BACK A LITTLE ON THE
AMOUNTS. AGAIN..WE ARE IN A BIT OF A LULL BETWEEN THE STRONG WARM
ADVECTION TO OUR EAST...AND THE STRONG FORCING AND DIVERGENT FLOW
ALOFT ASSOCIATED WITH THE UPPER LEVEL SYSTEM TO OUR WEST.
THURSDAY...THE UPPER LEVEL LOW CONTINUES TO LIFT NORTH THROUGH
EASTERN MONTANA...WHILE THE SURFACE LOW LIFTS NORTH TO NEAR
BISMARCK...THEN NORTHWEST TOWARDS WILLISTON. THIS PLACEMENT WOULD
BRING GREATEST PRECIPITATION AMOUNTS TO THE NORTHERN HALF OF THE
CWA...WITH DRIER AIR WORKING FROM SOUTH TO NORTH THURSDAY
AFTERNOON. THIS WOULD BRING AN END TO PRECIPITATION ACROSS THE
SOUTH HALF OF THE CWA...BUT COULD ALSO ALLOW FOR A PERIOD OF
DESTABILIZATION THURSDAY AFTERNOON IN THE DRIER AIR. WITH THE
SURFACE AND UPPER LOWS JUST WEST...THIS WOULD INCREASE THE RISK OF
THUNDERSTORMS IN A HIGH SHEAR ENVIRONMENT. DUE TO SOME MODEL AND
TIMING UNCERTAINTIES WILL NOT MENTION SEVERE AT THIS TIME...AND
LET LATER SHIFTS UPDATE AS NEEDED.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 405 PM CDT WED MAY 29 2013
WET AND COOL WEATHER REMAINS OVER THE NORTHERN PLAINS THROUGH EARLY
SATURDAY...FOLLOWED BY QUIET CONDITIONS SATURDAY THROUGH SUNDAY
AFTERNOON...THEN A RETURN TO ACTIVE CONDITIONS SUNDAY NIGHT THROUGH
TUESDAY.
THE LONG TERM BEGINS THURSDAY EVENING WITH A CLOSED UPPER LEVEL LOW
CENTERED OVER SOUTHWEST ND/SOUTHEASTERN MONTANA...AND AN AREA OF
SURFACE LOW PRESSURE OVER WESTERN NORTH DAKOTA. ACTIVE WEATHER WILL
BE ONGOING AT THE START OF THE PERIOD WITH WIDESPREAD RAIN SHOWERS
AND ISOLATED THUNDERSTORMS ACROSS THE NORTH AND FAR WEST WRAPPING
AROUND THE UPPER LOW. OVER SOUTH CENTRAL AND SOUTHEASTERN NORTH
DAKOTA...A DRY SLOT IS EXPECTED TO PROVIDE SOME CLEARING THURSDAY
AFTERNOON INTO THURSDAY EVENING...WITH THE RESULTANT HEATING ACTING
TO INCREASE SURFACE INSTABILITY WITH UPWARDS TO NEAR 1500 J/KG OF
CAPE FORECAST NEAR A SFC COLD/OCCLUDED FRONT. MAY SEE ISOLATED
SEVERE STORMS DEVELOP GIVEN THE ADVERTISED INSTABILITY PERSISTING
INTO THE EVENING NEAR THE BOUNDARY.
LOW LINGERS ACROSS THE NORTHERN PLAINS THROUGH FRIDAY BEFORE
MORPHING INTO AN OPEN WAVE AND PUSHING OFF TO OUR EAST SATURDAY
AFTERNOON. AS THIS OCCURS...WILL SEE WRAP AROUND PRECIPITATION
SPREAD FROM WEST TO EAST FRIDAY MORNING THROUGH FRIDAY
EVENING...THEN DECREASING CLOUDS AND CHANCES FOR RAIN FROM
NORTHWEST TO SOUTHEAST FRIDAY NIGHT INTO SATURDAY. OVERALL EXPECT
UPWARDS TO AN ADDITIONAL ONE HALF INCH OF RAINFALL THURSDAY NIGHT
THROUGH SATURDAY MORNING ACROSS WEST AND CENTRAL ND.
DRY WEATHER REMAINS IN THE FORECAST SATURDAY NIGHT THROUGH SUNDAY
AFTERNOON WITH A SHORT WAVE RIDGE AND SURFACE HIGH PRESSURE BUILDING
EAST ACROSS THE NORTHERN PLAINS. ACTIVE WEATHER RESUMES SUNDAY NIGHT
INTO EARLY NEXT WEEK AS ANOTHER UPPER LOW/TROUGH PUSHES ACROSS THE
NORTHERN ROCKIES AND EVENTUALLY INTO THE NORTHERN PLAINS.
WELL BELOW NORMAL TEMPERATURES FRIDAY AND SATURDAY WITH HIGHS 55-65
AND LOWS IN THE UPPER 30S TO MID 40S. WILL NEED TO MONITOR FOR
POSSIBLE FROST SATURDAY NIGHT/SUNDAY MORNING WHEN WINDS ARE EXPECTED
TO BE LIGHT...SKIES CLEAR...AND SFC DEWPOINT TEMPS FORECAST TO FALL
AS LOW AS 35F DEGREES SOME AREAS. DAYTIME AND NIGHTTIME TEMPERATURES
MODERATE TOWARDS NORMAL SUNDAY-TUESDAY WITH HIGHS GENERALLY IN THE
60S AND LOW 45-55.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY)
ISSUED AT 1231 AM CDT THU MAY 30 2013
SHOWERS AND THUNDERSTORMS WILL CONTINUE TO INCREASE IN COVERAGE
ACROSS WESTERN AND CENTRAL NORTH DAKOTA THROUGH THE NIGHT...WITH
FLIGHT CONDITIONS TRENDING TOWARDS MVFR/IFR AT ALL SITES IN MODERATE
RAIN AND LOW CEILINGS. DEPENDING ON HOW MUCH CLEARING THERE IS
THURSDAY AFTERNOON...STRONG TO SEVERE THUNDERSTORMS MAY BE
POSSIBLE FOR THE KDIK...KBIS AND KJMS TAF SITES THURSDAY AFTERNOON
AND EVENING.
&&
.HYDROLOGY...
ISSUED AT 405 PM CDT WED MAY 29 2013
SHOWERS AND THUNDERSTORMS ARE EXPECTED TO DEVELOP LATE THIS
AFTERNOON AND TONIGHT...AND MOVE FROM SOUTH TO NORTH ACROSS
WESTERN AND CENTRAL NORTH DAKOTA THROUGH THURSDAY AFTERNOON.
THE POTENTIAL FOR HEAVY RAIN EXISTS ACROSS THE WEST AND CENTRAL...
ESPECIALLY LATE TONIGHT THROUGH THURSDAY. WIDESPREAD RAINFALL
AMOUNTS OF THREE QUARTERS OF AN INCH...TO TWO INCHES ARE FORECAST
THOUGH THIS PERIOD. HOWEVER...THE LATEST GUIDANCE CONTINUES TO
SUGGEST A LESS LIKELY SCENARIO FOR AMOUNTS GREATER THAN 1.5 INCHES
OVER MUCH OF THE CENTRAL. THE MOST LIKELY AREAS FOR THE HIGHEST
AMOUNTS APPEAR TO BE IN THE FAR NORTH AND FAR WEST...WITH THE
HIGHEST AMOUNTS IN EASTERN MONTANA AND SOUTHERN CANADA.
STREAM AND RIVER RISES ARE POSSIBLE BY THE END OF THE WEEK INTO
THIS COMING WEEKEND. AN ADDITIONAL ONE QUARTER TO ONE HALF INCH
WILL BE POSSIBLE FRIDAY AND FRIDAY NIGHT. CHANCES FOR RAIN
DECREASE SATURDAY INTO SATURDAY NIGHT.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...JNS
SHORT TERM...TWH
LONG TERM...NH
AVIATION...JNS
HYDROLOGY...TWH
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
1026 PM EDT FRI MAY 31 2013
.SYNOPSIS...
WARM SECTOR THROUGH SATURDAY NIGHT WITH CONVECTION POSSIBLE
ESPECIALLY DURING DAYTIME HEATING HOURS. COLD FRONT CROSSES
SUNDAY. COOLER AND DRIER TO START NEXT WEEK.
&&
.NEAR TERM /THROUGH SATURDAY/...
1030 PM UPDATE...
NO CHANGES NEEDED AS CONVECTION OVER THE MIDDLE OHIO VALLEY WINDS
DOWN FOR THIS NT.
PREV DISCN...
18Z RADAR IMAGERY SHOWING SHOWERS AND THUNDERSTORMS CONTINUING TO
DEVELOP TO THE WEST ROUGHLY AROUND THE IN/OH BORDER AREA SOUTHWARD
INTO CENTRAL KENTUCKY. OUT AHEAD OF THAT GENERAL AREA A FEW DISCRETE
THUNDERSTORMS HAD FORMED TO THE EAST. PRIMARY CONCERNS IN THE NEAR
TERM REVOLVE AROUND THIS EVENING/S CONVECTION AS WELL AS
REDEVELOPING SHOWERS/THUNDERSTORMS TOMORROW.
THIS EVENING...TOUGH CALL ON EXACTLY HOW FAR EAST TO TAKE PRECIP
WITH A READILY-APPARENT DECAYING MCV PUSHING E/NE-WARD ACROSS NORTH
CENTRAL KY. LATEST RAP SEEMS TO HAVE SOMEWHAT OF A HANDLE ON THE
SHEAR ASSOC WITH IT...WITH NEAR 40KTS OF SHEAR DEPICTED ACROSS THE
SW OHIO AND NC KY AREAS. FURTHER EAST OVER OUR WESTERN ZONES...SHEAR
IS APPRECIABLY LOWER AND ONLY AROUND 15-20KTS. LATEST RAP RUNS ALSO
CONTINUE TO WEAKEN/SHEAR THE VORT MAX ASSOC WITH THE MCV...WITH
SHEAR VALUES ONLY CLIMBING TO AROUND 25KTS NEAR PERRY CO OH...AND
LESS POINTS EAST AND SOUTH OF THAT...BY 00Z. INSTABILITY WILL BE
DECREASING AS WELL AND BECOMING MORE ELEVATED AS USUAL...WHICH
SHOULD SPELL A DECREASING RISK OF STRONG WINDS. ALL IN ALL...DO
BELIEVE SHOWERS AND SOME THUNDERSTORMS STAND A DECENT CHANCE OF
REACHING OUR WESTERN ZONES AND PARTICULARLY THE SE OHIO ZONES. WHILE
A SEVERE THUNDERSTORM CAN/T BE COMPLETELY RULED OUT IN THOSE
LOCATIONS...CURRENT THINKING IS THAT THE BULK OF ANY SEVERE WX
REMAINS WEST.
OVERNIGHT...WILL KEEP GENERAL INHERITED FORECAST AND DRY OUT MOST
LOCATIONS BTWN 03Z-06Z. DID ELECT TO KEEP A SLIGHT CHANCE ACROSS THE
FAR NW ZONES HOWEVER...ON THE NOSE OF A 850MB JET. PREV FCST LOW
TEMPS IN THE MID/UPPER 60S LOWLANDS STILL LOOK GOOD. SLIGHTLY
STRONGER BL WINDS OVERNIGHT PROGGED AFTER 06Z SHOULD PRECLUDE
WIDESPREAD FOG FORMATION BUT THE USUAL SPOTS SUCH AS EKN WILL MOST
LIKELY SEE REDUCED VIS NEAR DAWN.
TOMORROW...INHERITED MAX TEMPS IN THE MID/UPPER 80S LOWLANDS LOOK
GOOD. PRIMARY FOCUS ON THUNDERSTORMS AND SVR THUNDERSTORM POTENTIAL.
NOT REALLY SEEING MUCH IN THE WAY OF ANY ORGANIZED LARGE-SCALE LIFT
FOR MUCH OF THE DAY WITH THE TROUGH AXIS AND SFC COLD FRONT STILL
WELL TO THE WEST. LOWERED POPS TO LOW CHANCE FOR THE MORNING HOURS
AND INTO THE EARLY AFTERNOON HOURS AS SUCH. BTWN 18Z-21Z...GOOD
DYNAMICS ARRIVE TO THE WEST OF OUR AREA...OVER IN/WEST OH SOUTHWARD
INTO CENTRAL KY. THIS AREA SHOULD SERVE FOR ORGANIZED CONVECTIVE
INITIATION BY 21Z...WITH SUPERCELLS A POSSIBILITY. THIS AREA WILL
SLOWLY PROGRESS EASTWARD...BUT RIGHT-MOVER MOTION WOULD TAKE THESE
STORMS IN AN MORE E/NE DIRECTION AROUND 30KTS. AGAIN AS WITH THIS
AFTERNOON...THE BULK OF SVR WX SHOULD REMAIN WEST BUT WITH BETTER
SHEAR OVER OUR AREA TOMORROW A BETTER LIKELIHOOD OF SVR WX OVER OUR
WESTERN ZONES EXISTS PRIMARILY LATE AFTERNOON INTO MID-EVE HOURS.
&&
.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY NIGHT/...
COLD FRONT WILL PUSH EAST INTO THE CWA SUNDAY MORNING. TIMING OF THE
FRONT LOOKS TO BE A FEW HOURS SLOWER THAN PREVIOUS RUNS...BUT STILL
THINKING MUCH OF THE CWA WILL NOT SEE MUCH IN TERMS OF SEVERE DUE TO
TIMING...ALTHOUGH THE EASTERN ZONES WILL BE MORE SUSCEPTIBLE DUE TO
LATER FRONTAL PASSAGE. DECENT CAPE...GENERALLY 1500-2000
J/KG...ALONG WITH 30-40 KTS 0-6KM BULK SHEAR WILL CREATE A POTENTIAL
FOR STRONG STORMS...WITH WINDS...AND HAIL THE PRIMARY
THREATS...MAINLY ACROSS THE EAST. HOWEVER...PLENTY OF CLOUD COVER
OUT AHEAD OF THE FRONT MAY ALSO HELP TO MITIGATE THE SEVERE
THREAT...ESPECIALLY EARLY ON. SO FOR NOW...ITS A WAIT AND SEE
SCENARIO TO SEE IF ANY OF THE ABOVE MENTIONED FACTORS ARE ABLE TO
LINE UP...BUT LOOKING LIKE BULK OF SEVERE THREAT WILL BE TO THE EAST
OF THE CWA. AS OF RIGHT NOW...SPC HAS THE SLIGHT RISK TO THE EAST OF
THE CWA...WITH CWA IN GENERAL THUNDER...AND A 5 PERCENT PROB OUTLOOK
FOR SEVERE.
COLD FRONT WILL EXIT TO THE EAST OF THE CWA SUNDAY NIGHT...WITH
COOLER AND DRIER WEATHER TAKING HOLD.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
GENERALLY FOLLOWED WPC THINKING WITH SOME TWEAKS.
HIGH PRESSURE WILL DOMINATE THE REGION ON TUESDAY...WITH
TEMPERATURES NEAR NORMAL READINGS. HOWEVER...THE HIGH WILL PUSH
EAST ON WEDNESDAY...RESULTING IN SOUTHERLY WINDS AND WARMER
TEMPERATURES. THE SOUTHERLY WINDS WILL ALSO RESULT IN INCREASING
LOW-LEVEL MOISTURE AND THE CHANCES FOR SHOWERS AND STORMS...MAINLY
DIURNAL IN NATURE...WILL ALSO RETURN THROUGH THE REMAINDER OF THE
PERIOD.
&&
.AVIATION /03Z SATURDAY THROUGH WEDNESDAY/...
SHOWERS AND A FEW THUNDERSTORMS IN E OHIO MAY REACH THE OHIO RIVER
BEFORE DISSIPATING LATER THIS EVENING. IT DOES NOT LOOK LIKE TAF
SITES WILL BE IMPACTED AT THIS TIME SO VFR EVENING EXPECTED.
DENSE FOG IS LIKELY TO FORM OVERNIGHT IN THE TYGART VALLEY...WITH
MVFR MIST IN OTHER VALLEYS E OF THE OHIO RIVER.
VFR DAY EXPECTED SAT...WITH MORNING ALTOCU AND THEN MIDDAY AND
AFTERNOON HIGH BASED CU. SCATTERED SHOWERS AND THUNDERSTORMS WILL
FORM IN THE AFTERNOON HEATING...AND THEN START TO BECOME NUMEROUS W
OF THE OHIO RIVER TOWARD 00Z SUN...WHERE THERE IS A SLIGHT RISK FOR
SEVERE THUNDERSTORMS.
LIGHT S TO SW SFC FLOW WILL GO CALM IN THE VALLEYS OVERNIGHT...AND
THEN BECOME A BIT GUSTY AREA WIDE SAT. FLOW ALOFT WILL REMAIN
MODERATE SW...BECOMING A BIT STRONGER W OF THE OHIO RIVER LATE SAT.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 00Z SUNDAY...
FORECAST CONFIDENCE...HIGH.
ALTERNATE SCENARIOS: DEVELOPMENT AND TIMING OF DENSE FOG IN TYGART
VALLEY OVERNIGHT MAY VARY...INCLUDING THE CHANCE IT DOES NOT FORM AT
ALL OR AT LEAST GETS NO WORSE THAN MVFR. IT WAS TOO EARLY TO
EXPLICITLY CODE IMPACTS OF THUNDERSTORMS AT TAF SITES SAT
AFTERNOON...BUT SUCH EFFECTS ARE POSSIBLE...WITH IFR CONDITIONS AND
STRONG WIND GUSTS POSSIBLE IN ANY THUNDERSTORM SAT AFTERNOON.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
DATE SAT 06/01/13
UTC 1HRLY 02 03 04 05 06 07 08 09 10 11 12 13
EDT 1HRLY 22 23 00 01 02 03 04 05 06 07 08 09
CRW CONSISTENCY H H H H H M M M H H H H
HTS CONSISTENCY H H H H H H H H H H H H
BKW CONSISTENCY H H H H H H H H H H H H
EKN CONSISTENCY H H M M L L L L L H H H
PKB CONSISTENCY H H H H H H H H H H H H
CKB CONSISTENCY H H H H M M M M H H H H
AFTER 00Z SUNDAY...
IFR POSSIBLE IN SHOWERS AND THUNDERSTORMS SUNDAY INTO SUNDAY
NIGHT...AND IN POST-RAIN FOG AND LOW CLOUDS LATE SUNDAY NIGHT INTO
MONDAY MORNING.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...JSH/50/SL
NEAR TERM...TRM/50
SHORT TERM...SL
LONG TERM...JSH
AVIATION...TRM
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
750 PM EDT FRI MAY 31 2013
.SYNOPSIS...
WARM SECTOR THROUGH SATURDAY NIGHT WITH CONVECTION POSSIBLE
ESPECIALLY DURING DAYTIME HEATING HOURS. COLD FRONT CROSSES
SUNDAY. COOLER AND DRIER TO START NEXT WEEK.
&&
.NEAR TERM /THROUGH SATURDAY/...
18Z RADAR IMAGERY SHOWING SHOWERS AND THUNDERSTORMS CONTINUING TO
DEVELOP TO THE WEST ROUGHLY AROUND THE IN/OH BORDER AREA SOUTHWARD
INTO CENTRAL KENTUCKY. OUT AHEAD OF THAT GENERAL AREA A FEW DISCRETE
THUNDERSTORMS HAD FORMED TO THE EAST. PRIMARY CONCERNS IN THE NEAR
TERM REVOLVE AROUND THIS EVENING/S CONVECTION AS WELL AS
REDEVELOPING SHOWERS/THUNDERSTORMS TOMORROW.
THIS EVENING...TOUGH CALL ON EXACTLY HOW FAR EAST TO TAKE PRECIP
WITH A READILY-APPARENT DECAYING MCV PUSHING E/NE-WARD ACROSS NORTH
CENTRAL KY. LATEST RAP SEEMS TO HAVE SOMEWHAT OF A HANDLE ON THE
SHEAR ASSOC WITH IT...WITH NEAR 40KTS OF SHEAR DEPICTED ACROSS THE
SW OHIO AND NC KY AREAS. FURTHER EAST OVER OUR WESTERN ZONES...SHEAR
IS APPRECIABLY LOWER AND ONLY AROUND 15-20KTS. LATEST RAP RUNS ALSO
CONTINUE TO WEAKEN/SHEAR THE VORT MAX ASSOC WITH THE MCV...WITH
SHEAR VALUES ONLY CLIMBING TO AROUND 25KTS NEAR PERRY CO OH...AND
LESS POINTS EAST AND SOUTH OF THAT...BY 00Z. INSTABILITY WILL BE
DECREASING AS WELL AND BECOMING MORE ELEVATED AS USUAL...WHICH
SHOULD SPELL A DECREASING RISK OF STRONG WINDS. ALL IN ALL...DO
BELIEVE SHOWERS AND SOME THUNDERSTORMS STAND A DECENT CHANCE OF
REACHING OUR WESTERN ZONES AND PARTICULARLY THE SE OHIO ZONES. WHILE
A SEVERE THUNDERSTORM CAN/T BE COMPLETELY RULED OUT IN THOSE
LOCATIONS...CURRENT THINKING IS THAT THE BULK OF ANY SEVERE WX
REMAINS WEST.
OVERNIGHT...WILL KEEP GENERAL INHERITED FORECAST AND DRY OUT MOST
LOCATIONS BTWN 03Z-06Z. DID ELECT TO KEEP A SLIGHT CHANCE ACROSS THE
FAR NW ZONES HOWEVER...ON THE NOSE OF A 850MB JET. PREV FCST LOW
TEMPS IN THE MID/UPPER 60S LOWLANDS STILL LOOK GOOD. SLIGHTLY
STRONGER BL WINDS OVERNIGHT PROGGED AFTER 06Z SHOULD PRECLUDE
WIDESPREAD FOG FORMATION BUT THE USUAL SPOTS SUCH AS EKN WILL MOST
LIKELY SEE REDUCED VIS NEAR DAWN.
TOMORROW...INHERITED MAX TEMPS IN THE MID/UPPER 80S LOWLANDS LOOK
GOOD. PRIMARY FOCUS ON THUNDERSTORMS AND SVR THUNDERSTORM POTENTIAL.
NOT REALLY SEEING MUCH IN THE WAY OF ANY ORGANIZED LARGE-SCALE LIFT
FOR MUCH OF THE DAY WITH THE TROUGH AXIS AND SFC COLD FRONT STILL
WELL TO THE WEST. LOWERED POPS TO LOW CHANCE FOR THE MORNING HOURS
AND INTO THE EARLY AFTERNOON HOURS AS SUCH. BTWN 18Z-21Z...GOOD
DYNAMICS ARRIVE TO THE WEST OF OUR AREA...OVER IN/WEST OH SOUTHWARD
INTO CENTRAL KY. THIS AREA SHOULD SERVE FOR ORGANIZED CONVECTIVE
INITIATION BY 21Z...WITH SUPERCELLS A POSSIBILITY. THIS AREA WILL
SLOWLY PROGRESS EASTWARD...BUT RIGHT-MOVER MOTION WOULD TAKE THESE
STORMS IN AN MORE E/NE DIRECTION AROUND 30KTS. AGAIN AS WITH THIS
AFTERNOON...THE BULK OF SVR WX SHOULD REMAIN WEST BUT WITH BETTER
SHEAR OVER OUR AREA TOMORROW A BETTER LIKELIHOOD OF SVR WX OVER OUR
WESTERN ZONES EXISTS PRIMARILY LATE AFTERNOON INTO MID-EVE HOURS.
&&
.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY NIGHT/...
COLD FRONT WILL PUSH EAST INTO THE CWA SUNDAY MORNING. TIMING OF THE
FRONT LOOKS TO BE A FEW HOURS SLOWER THAN PREVIOUS RUNS...BUT STILL
THINKING MUCH OF THE CWA WILL NOT SEE MUCH IN TERMS OF SEVERE DUE TO
TIMING...ALTHOUGH THE EASTERN ZONES WILL BE MORE SUSCEPTIBLE DUE TO
LATER FRONTAL PASSAGE. DECENT CAPE...GENERALLY 1500-2000
J/KG...ALONG WITH 30-40 KTS 0-6KM BULK SHEAR WILL CREATE A POTENTIAL
FOR STRONG STORMS...WITH WINDS...AND HAIL THE PRIMARY
THREATS...MAINLY ACROSS THE EAST. HOWEVER...PLENTY OF CLOUD COVER
OUT AHEAD OF THE FRONT MAY ALSO HELP TO MITIGATE THE SEVERE
THREAT...ESPECIALLY EARLY ON. SO FOR NOW...ITS A WAIT AND SEE
SCENARIO TO SEE IF ANY OF THE ABOVE MENTIONED FACTORS ARE ABLE TO
LINE UP...BUT LOOKING LIKE BULK OF SEVERE THREAT WILL BE TO THE EAST
OF THE CWA. AS OF RIGHT NOW...SPC HAS THE SLIGHT RISK TO THE EAST OF
THE CWA...WITH CWA IN GENERAL THUNDER...AND A 5 PERCENT PROB OUTLOOK
FOR SEVERE.
COLD FRONT WILL EXIT TO THE EAST OF THE CWA SUNDAY NIGHT...WITH
COOLER AND DRIER WEATHER TAKING HOLD.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
GENERALLY FOLLOWED WPC THINKING WITH SOME TWEAKS.
HIGH PRESSURE WILL DOMINATE THE REGION ON TUESDAY...WITH
TEMPERATURES NEAR NORMAL READINGS. HOWEVER...THE HIGH WILL PUSH
EAST ON WEDNESDAY...RESULTING IN SOUTHERLY WINDS AND WARMER
TEMPERATURES. THE SOUTHERLY WINDS WILL ALSO RESULT IN INCREASING
LOW-LEVEL MOISTURE AND THE CHANCES FOR SHOWERS AND STORMS...MAINLY
DIURNAL IN NATURE...WILL ALSO RETURN THROUGH THE REMAINDER OF THE
PERIOD.
&&
.AVIATION /00Z SATURDAY THROUGH WEDNESDAY/...
SHOWERS AND A FEW THUNDERSTORMS IN E OHIO MAY REACH THE OHIO RIVER
BEFORE DISSIPATING LATER THIS EVENING. IT DOES NOT LOOK LIKE TAF
SITES WILL BE IMPACTED AT THIS TIME SO VFR EVENING EXPECTED.
DENSE FOG IS LIKELY TO FORM OVERNIGHT IN THE TYGART VALLEY...WITH
MVFR MIST IN OTHER VALLEYS E OF THE OHIO RIVER.
VFR DAY EXPECTED SAT...WITH MORNING ALTOCU AND THEN MIDDAY AND
AFTERNOON HIGH BASED CU. SCATTERED SHOWERS AND THUNDERSTORMS WILL
FORM IN THE AFTERNOON HEATING...AND THEN START TO BECOME NUMEROUS W
OF THE OHIO RIVER TOWARD 00Z SUN...WHERE THERE IS A SLIGHT RISK FOR
SEVERE THUNDERSTORMS.
LIGHT S TO SW SFC FLOW WILL GO CALM IN THE VALLEYS OVERNIGHT...AND
THEN BECOME A BIT GUSTY AREA WIDE SAT. FLOW ALOFT WILL REMAIN
MODERATE SW...BECOMING A BIT STRONGER W OF THE OHIO RIVER LATE SAT.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 00Z SUNDAY...
FORECAST CONFIDENCE...HIGH.
ALTERNATE SCENARIOS: DEVELOPMENT AND TIMING OF DENSE FOG IN TYGART
VALLEY OVERNIGHT MAY VARY...INCLUDING THE CHANCE IT DOES NOT FORM AT
ALL OR AT LEAST GETS NO WORSE THAN MVFR. IT WAS TOO EARLY TO
EXPLICITLY CODE IMPACTS OF THUNDERSTORMS AT TAF SITES SAT
AFTERNOON...BUT SUCH EFFECTS ARE POSSIBLE...WITH IFR CONDITIONS AND
STRONG WIND GUSTS POSSIBLE IN ANY THUNDERSTORM SAT AFTERNOON.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
DATE SAT 06/01/13
UTC 1HRLY 00 01 02 03 04 05 06 07 08 09 10 11
EDT 1HRLY 20 21 22 23 00 01 02 03 04 05 06 07
CRW CONSISTENCY H H H H H H H M M M H H
HTS CONSISTENCY H H H H H H H H H H H H
BKW CONSISTENCY H H H H H H H H H H H H
EKN CONSISTENCY H H H H M M L L L L L H
PKB CONSISTENCY H H H H H H H H H H H H
CKB CONSISTENCY H H H H H H M M M M H H
AFTER 00Z SUNDAY...
IFR POSSIBLE IN SHOWERS AND THUNDERSTORMS SUNDAY INTO SUNDAY
NIGHT...AND IN POST-RAIN FOG AND LOW CLOUDS LATE SUNDAY NIGHT INTO
MONDAY MORNING.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...JSH/50/SL
NEAR TERM...TRM/50
SHORT TERM...SL
LONG TERM...JSH
AVIATION...TRM
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
736 AM EDT THU MAY 30 2013
.SYNOPSIS...
HIGH PRESSURE CENTERED OVER THE ATLANTIC WILL KEEP US DRY WITH
TEMPERATURES SLIGHTLY ABOVE AVERAGE THROUGH THE END OF THE WEEK. THE
HIGH MOVES OFF THE ATLANTIC COAST OVER THE WEEKEND...AND A COLD
FRONT APPROACHES BY EARLY NEXT WEEK...RETURNING US TO AN UNSETTLED
PATTERN.
&&
.NEAR TERM /THROUGH TONIGHT/...
THE AREAL DISTRIBUTION OF CLOUD COVER IS WORKING OUT ABOUT AS
EXPECTED...WITH OVERCAST SKIES OVER THE SRN APPALACHAINS...THE WRN
UPSTATE AND NE GA. THE MOISTURE MAY NOT BE AS SHALLOW AS I
ORIGINALLY THOUGHT AND SOME LOCATIONS IN THIS AREA MAY BE CLOUDY
THROUGH NOON. FARTHER TO THE EAST...INCLUDING THE WRN NC PIEDMONT
AND THE NE UPSTATE...THE LLVLS ARE DRIER AND IT SHOULD BE MAINLY
SUNNY EXPECT FOR SOME CIRRUS AND A FEW CU THAT WILL LIFT AN HOUR OR
TWO AFTER SUNRISE.
AS OF 440 AM EDT THURSDAY...MVFR CIGS ARE FILLING IN QUICKLY OVER NE
GA AND WE APPEAR TO BE ON TRACK FOR A STRATUS DECK TO INVADE THE
FORECAST AREA FROM THE SOUTHWEST OVER THE NEXT FEW HOURS. I DID
TWEAK SKY COVER TO ACCOUNT FOR CURRENT TRENDS...HOWEVER.
AS OF 300 AM EDT THURSDAY...MVFR LEVEL STRATUS IS EXPANDING ACROSS
SOUTHERN AND CENTRAL GA EARLY THIS THURSDAY MORNING. THE SREF SHOWS
A HIGH PROBABILITY THAT IT WILL CONTINUE TO EXPAND NORTH AND
NORTHEAST...EVENTUALLY SPREADING ACROSS NE GA...THE WRN UPSTATE AND
THE SRN NC MTNS. I/VE CARRIED MOSTLY CLOUDY SKIES EARLY IN THE DAY
TO ACCOUNT FOR THIS...BUT THE CLOUD LAYER SHOULD BE SHALLOW AND
SHOULD MIX INTO A CU FIELD FAIRLY QUICKLY BY LATE MORNING. OTHERWISE
IT WILL BE DRY ACROSS THE ENTIRE FORECAST AREA TODAY WITH MAX TEMPS
RUNNING ABOUT A CATEGORY ABOVE NORMAL.
WE WILL PROBABLY SEE STRATUS DEVELOP AGAIN TONIGHT. IN FACT...WITH
HIGHER BNDRY LAYER RH/S AND A STRONGER WIND FIELD...IT IS LIKELY TO
COVER MOST OF THE FORECAST AREA. STILL...IT/S NOT A GIVEN THAT THIS
WILL HAPPEN AND MY SKY COVER IS RATHER LOW...ESPECIALLY ACROSS WRN
NC.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 245 AM THURSDAY...UPPER RIDGE WILL BEGIN TO BREAK DOWN AND
SHIFT EAST FURTHER OFF THE ATLANTIC COAST DURING THE SHORT
TERM...BUT OVERALL WILL CONTINUE TO INFLUENCE OUR SENSIBLE WX. LLVL
FLOW WILL REMAIN LIGHT GENERALLY OUT OF THE S/SE OFF THE ATLANTIC.
MODELS IN BETTER AGREEMENT ON MORNING STRATUS DEVELOPING AND BEING A
LITTLE BIT MORE WIDESPREAD FRIDAY MORNING...BUT SHUD SCATTER OUT BY
MIDDAY. FCST SNDGS SHOW WEAK CAPE WITH INHIBITION FRI AFTN...SO
GOING WITH A DRY FCST.
ON SATURDAY...ONCE AGAIN...GUIDANCE INDICATING MORNING STRATUS
DEVELOPMENT...WITH INCREASE IN SOME MID-UPR MOISTURE AS WELL.
OVERALL...STILL LOOKS LIKE ANOTHER DRY DAY...ALTHO WILL KEEP A SLGT
CHC POP FOR THE NC MTNS...THANKS TO SOME INCREASED MOISTURE IN A
VEERING SWLY LLVL FLOW. HIGHS BOTH DAYS WILL BE SIMILAR TO LAST
COUPLE OF DAYS...ABOUT A CATEGORY OR TWO ABOVE NORMAL...WITH NEAR OR
SLIGHTLY ABOVE NORMAL OVERNIGHT LOWS.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
AS OF 300 AM THURSDAY...UNSETTLED WEATHER LOOKS TO RETURN THE CWFA
FOR SUNDAY INTO EARLY NEXT WEEK.
A COLD FRONT WILL APPROACH THE AREA FROM THE WEST ON SUNDAY...WITH A
PLUME OF DEEP RH AND HEIGHT FALLS ENTERING THE NC MTNS BY PEAK
HEATING. SO A SOLID CHC TO LOW-END LIKELY POPS FOR SUNDAY LOOKS
GOOD. CONVECTION MAY LINGER INTO THE NIGHT IN THE MOIST AIR MASS
WITH SOME UPR SUPPORT. THE FRONT IS PROGGED TO SETTLE ROUGHLY ALONG
THE BLUE RIDGE ON MONDAY...WITH PLENTY OF AFTN INSTBY ONCE AGAIN.
EXPECTING SCATTERED TO NUMEROUS SHWRS AND TSTMS TO
DEVELOP...POSSIBLY MOST FAVORED IN THE PIEDMONT ON WARM SIDE OF THE
FRONT. HIGHS WILL BE NEAR NORMAL BOTH DAYS...WITH SLIGHTLY ABOVE
NORMAL OVERNIGHT TEMPS.
THE FORECAST FOR TUESDAY AND WEDNESDAY WERE UNCHANGED...AS LATEST
MODEL TRENDS AND THE 00Z WPC GRIDS ARE IN LINE WITH EARLIER
THINKING. STILL EXPECTING THE FRONT TO SAG SE THRU THE CAROLINAS ON
TUESDAY...WITH A LINGERING CHC POP MAINLY SE OF I-85. THEN JUST A
SLGT CHC POP FOR MOST OF THE AREA ON WEDNESDAY...AS CANADIAN HIGH
PRES BUILDS IN ACRS THE GREAT LAKES TO THE SOUTHEAST STATES. TEMPS
WILL BE NEAR NORMAL.
&&
.AVIATION /12Z THURSDAY THROUGH MONDAY/...
AT KCLT...MVFR STRATUS HAS DEVELOPED ALONG THE BLUE RIDGE AND BACK
ACROSS THE CENTRAL AND WESTERN UPSTATE...BUT THE RUC AND SREF IMPLY
THAT THE LOW CLOUDS WILL STAY WEST OF THE AIRFIELD THIS MORNING.
HOWEVER...THERE WILL BE SOME SHALLOW GROUND FOG AROUND THE REGION
THIS MORNING. TYPICALLY THIS DOESN/T AFFECT KCLT AND NOTHING HAS
BEEN INCLUDED. STRATUS LOOKS MORE LIKELY TONIGHT AND A LOT OF
GUIDANCE IS POINTING TO CIGS IN THE IFR RANGE. I/VE HEDGED A LITTLE
AT THIS POINT AND GONE WITH SCT010...BUT THIS ALMOST CERTAINLY
OVERLY OPTIMISTIC.
ELSEWHERE...IT/S INTERESTING THAT THE LATEST RUN OF THE SREF AS WELL
AS THE HI RES WRF-NMM AND WRF-ARW ARE NOT DOING AS GOOD A JOB WITH
THE ORIENTATION OF THE STRATUS DECK THAT HAS MOVED INTO THE REGION
AS THEIR PREVIOUS RUNS. AT ANY RATE...AN MVFR DECK CURRENTLY COVERS
THE UPSTATE AND UPPER FRENCH BROAD VALLEY FROM KGSP AND KAVL
EASTWARD. THE CLOUDS HAVE LOWERED INTO THE IFR RANGE UPSTREAM OF THE
REGION AT KGVL AND KAHN. KAND MAY SEE A PERIOD OF IFR...BUT I THINK
MOST SITES WILL STAY BETWEEN 1200-1500 FEET. THE COLD COVER IS
RATHER EXTENSIVE UPSTREAM. THE LATEST RUC 925 MB RH FIELD IMPLIES
THAT WE MAY HOLD ON TO CIGS THROUGH NOON...THOUGH I THINK THEY WILL
GRADUALLY RISE.
STRATUS SHOULD BE EVEN MORE WIDESPREAD AND LOWER TONIGHT. THE LATEST
SREF...NAM BUKFIT AND GFS MOS INDICATE THAT WE WILL SEE IFR CIGS. I
HAVE INCLUDED THIS AT THE UPSTATE AND KAVL. I KEPT CIGS A BIT HIGHER
AT KHKY...WHERE PROBS ARE A BIT LOWER...BUT I SUSPECT THEY WILL SEE
IFR AS WELL.
OUTLOOK...GENERALLY FAIR CONDITIONS ARE EXPECTED THROUGH SATURDAY.
HOWEVER...RESTRICTIONS FROM MORNING STRATUS...AND POSSIBLY
FOG...WILL CONTINUE EACH MORNING THRU SUNDAY. CHANCES FOR MAINLY
AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS WILL INCREASE
SIGNIFICANTLY BY SUNDAY AFTERNOON...AS A COLD FRONT APPROACHES FROM
THE TN VALLEY.
CONFIDENCE TABLE...
11-17Z 17-23Z 23-05Z 05-11Z
KCLT HIGH 100% HIGH 100% HIGH 100% HIGH 90%
KGSP LOW 58% HIGH 100% HIGH 100% HIGH 93%
KAVL MED 67% HIGH 100% HIGH 100% HIGH 93%
KHKY MED 72% HIGH 100% HIGH 100% MED 75%
KGMU LOW 58% HIGH 100% HIGH 100% HIGH 95%
KAND MED 74% HIGH 100% HIGH 100% HIGH 98%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...ARK
NEAR TERM...MCAVOY
SHORT TERM...ARK
LONG TERM...ARK
AVIATION...MCAVOY
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
640 AM EDT THU MAY 30 2013
.SYNOPSIS...
HIGH PRESSURE CENTERED OVER THE ATLANTIC WILL KEEP US DRY WITH
TEMPERATURES SLIGHTLY ABOVE AVERAGE THROUGH THE END OF THE WEEK. THE
HIGH MOVES OFF THE ATLANTIC COAST OVER THE WEEKEND...AND A COLD
FRONT APPROACHES BY EARLY NEXT WEEK...RETURNING US TO AN UNSETTLED
PATTERN.
&&
.NEAR TERM /THROUGH TONIGHT/...
THE AREAL DISTRIBUTION OF CLOUD COVER IS WORKING OUT ABOUT AS
EXPECTED...WITH OVERCAST SKIES OVER THE SRN APPALACHAINS...THE WRN
UPSTATE AND NE GA. THE MOISTURE MAY NOT BE AS SHALLOW AS I
ORIGINALLY THOUGHT AND SOME LOCATIONS IN THIS AREA MAY BE CLOUDY
THROUGH NOON. FARTHER TO THE EAST...INCLUDING THE WRN NC PIEDMONT
AND THE NE UPSTATE...THE LLVLS ARE DRIER AND IT SHOULD BE MAINLY
SUNNY EXPECT FOR SOME CIRRUS AND A FEW CU THAT WILL LIFT AN HOUR OR
TWO AFTER SUNRISE.
AS OF 440 AM EDT THURSDAY...MVFR CIGS ARE FILLING IN QUICKLY OVER NE
GA AND WE APPEAR TO BE ON TRACK FOR A STRATUS DECK TO INVADE THE
FORECAST AREA FROM THE SOUTHWEST OVER THE NEXT FEW HOURS. I DID
TWEAK SKY COVER TO ACCOUNT FOR CURRENT TRENDS...HOWEVER.
AS OF 300 AM EDT THURSDAY...MVFR LEVEL STRATUS IS EXPANDING ACROSS
SOUTHERN AND CENTRAL GA EARLY THIS THURSDAY MORNING. THE SREF SHOWS
A HIGH PROBABILITY THAT IT WILL CONTINUE TO EXPAND NORTH AND
NORTHEAST...EVENTUALLY SPREADING ACROSS NE GA...THE WRN UPSTATE AND
THE SRN NC MTNS. I/VE CARRIED MOSTLY CLOUDY SKIES EARLY IN THE DAY
TO ACCOUNT FOR THIS...BUT THE CLOUD LAYER SHOULD BE SHALLOW AND
SHOULD MIX INTO A CU FIELD FAIRLY QUICKLY BY LATE MORNING. OTHERWISE
IT WILL BE DRY ACROSS THE ENTIRE FORECAST AREA TODAY WITH MAX TEMPS
RUNNING ABOUT A CATEGORY ABOVE NORMAL.
WE WILL PROBABLY SEE STRATUS DEVELOP AGAIN TONIGHT. IN FACT...WITH
HIGHER BNDRY LAYER RH/S AND A STRONGER WIND FIELD...IT IS LIKELY TO
COVER MOST OF THE FORECAST AREA. STILL...IT/S NOT A GIVEN THAT THIS
WILL HAPPEN AND MY SKY COVER IS RATHER LOW...ESPECIALLY ACROSS WRN
NC.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 245 AM THURSDAY...UPPER RIDGE WILL BEGIN TO BREAK DOWN AND
SHIFT EAST FURTHER OFF THE ATLANTIC COAST DURING THE SHORT
TERM...BUT OVERALL WILL CONTINUE TO INFLUENCE OUR SENSIBLE WX. LLVL
FLOW WILL REMAIN LIGHT GENERALLY OUT OF THE S/SE OFF THE ATLANTIC.
MODELS IN BETTER AGREEMENT ON MORNING STRATUS DEVELOPING AND BEING A
LITTLE BIT MORE WIDESPREAD FRIDAY MORNING...BUT SHUD SCATTER OUT BY
MIDDAY. FCST SNDGS SHOW WEAK CAPE WITH INHIBITION FRI AFTN...SO
GOING WITH A DRY FCST.
ON SATURDAY...ONCE AGAIN...GUIDANCE INDICATING MORNING STRATUS
DEVELOPMENT...WITH INCREASE IN SOME MID-UPR MOISTURE AS WELL.
OVERALL...STILL LOOKS LIKE ANOTHER DRY DAY...ALTHO WILL KEEP A SLGT
CHC POP FOR THE NC MTNS...THANKS TO SOME INCREASED MOISTURE IN A
VEERING SWLY LLVL FLOW. HIGHS BOTH DAYS WILL BE SIMILAR TO LAST
COUPLE OF DAYS...ABOUT A CATEGORY OR TWO ABOVE NORMAL...WITH NEAR OR
SLIGHTLY ABOVE NORMAL OVERNIGHT LOWS.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
AS OF 300 AM THURSDAY...UNSETTLED WEATHER LOOKS TO RETURN THE CWFA
FOR SUNDAY INTO EARLY NEXT WEEK.
A COLD FRONT WILL APPROACH THE AREA FROM THE WEST ON SUNDAY...WITH A
PLUME OF DEEP RH AND HEIGHT FALLS ENTERING THE NC MTNS BY PEAK
HEATING. SO A SOLID CHC TO LOW-END LIKELY POPS FOR SUNDAY LOOKS
GOOD. CONVECTION MAY LINGER INTO THE NIGHT IN THE MOIST AIR MASS
WITH SOME UPR SUPPORT. THE FRONT IS PROGGED TO SETTLE ROUGHLY ALONG
THE BLUE RIDGE ON MONDAY...WITH PLENTY OF AFTN INSTBY ONCE AGAIN.
EXPECTING SCATTERED TO NUMEROUS SHWRS AND TSTMS TO
DEVELOP...POSSIBLY MOST FAVORED IN THE PIEDMONT ON WARM SIDE OF THE
FRONT. HIGHS WILL BE NEAR NORMAL BOTH DAYS...WITH SLIGHTLY ABOVE
NORMAL OVERNIGHT TEMPS.
THE FORECAST FOR TUESDAY AND WEDNESDAY WERE UNCHANGED...AS LATEST
MODEL TRENDS AND THE 00Z WPC GRIDS ARE IN LINE WITH EARLIER
THINKING. STILL EXPECTING THE FRONT TO SAG SE THRU THE CAROLINAS ON
TUESDAY...WITH A LINGERING CHC POP MAINLY SE OF I-85. THEN JUST A
SLGT CHC POP FOR MOST OF THE AREA ON WEDNESDAY...AS CANADIAN HIGH
PRES BUILDS IN ACRS THE GREAT LAKES TO THE SOUTHEAST STATES. TEMPS
WILL BE NEAR NORMAL.
&&
.AVIATION /12Z THURSDAY THROUGH MONDAY/...
AT KCLT...MVFR STRATUS HAS DEVELOPED ALONG THE BLUE RIDGE AND BACK
ACROSS THE CENTRAL AND WESTERN UPSTATE...BUT THE RUC AND SREF IMPLY
THAT THE LOW CLOUDS WILL STAY WEST OF THE AIRFIELD THIS MORNING.
HOWEVER...THERE WILL BE SOME SHALLOW GROUND FOG AROUND THE REGION
THIS MORNING. TYPICALLY THIS DOESN/T AFFECT KCLT AND NOTHING HAS
BEEN INCLUDED. STRATUS LOOKS MORE LIKELY TONIGHT AND A LOT OF
GUIDANCE IS POINTING TO CIGS IN THE IFR RANGE. I/VE HEDGED A LITTLE
AT THIS POINT AND GONE WITH SCT010...BUT THIS ALMOST CERTAINLY
OVERLY OPTIMISTIC.
ELSEWHERE...IT/S INTERESTING THAT THE LATEST RUN OF THE SREF AS WELL
AS THE HI RES WRF-NMM AND WRF-ARW ARE NOT DOING AS GOOD A JOB WITH
THE ORIENTATION OF THE STRATUS DECK THAT HAS MOVED INTO THE REGION
AS THEIR PREVIOUS RUNS. AT ANY RATE...AN MVFR DECK CURRENTLY COVERS
THE UPSTATE AND UPPER FRENCH BROAD VALLEY FROM KGSP AND KAVL
EASTWARD. THE CLOUDS HAVE LOWERED INTO THE IFR RANGE UPSTREAM OF THE
REGION AT KGVL AND KAHN. KAND MAY SEE A PERIOD OF IFR...BUT I THINK
MOST SITES WILL STAY BETWEEN 1200-1500 FEET. THE COLD COVER IS
RATHER EXTENSIVE UPSTREAM. THE LATEST RUC 925 MB RH FIELD IMPLIES
THAT WE MAY HOLD ON TO CIGS THROUGH NOON...THOUGH I THINK THEY WILL
GRADUALLY RISE.
STRATUS SHOULD BE EVEN MORE WIDESPREAD AND LOWER TONIGHT. THE LATEST
SREF...NAM BUKFIT AND GFS MOS INDICATE THAT WE WILL SEE IFR CIGS. I
HAVE INCLUDED THIS AT THE UPSTATE AND KAVL. I KEPT CIGS A BIT HIGHER
AT KHKY...WHERE PROBS ARE A BIT LOWER...BUT I SUSPECT THEY WILL SEE
IFR AS WELL.
OUTLOOK...GENERALLY FAIR CONDITIONS ARE EXPECTED THROUGH SATURDAY.
HOWEVER...RESTRICTIONS FROM MORNING STRATUS...AND POSSIBLY
FOG...WILL CONTINUE EACH MORNING THRU SUNDAY. CHANCES FOR MAINLY
AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS WILL INCREASE
SIGNIFICANTLY BY SUNDAY AFTERNOON...AS A COLD FRONT APPROACHES FROM
THE TN VALLEY.
CONFIDENCE TABLE...
10-16Z 16-22Z 22-04Z 04-10Z
KCLT HIGH 100% HIGH 100% HIGH 100% HIGH 95%
KGSP MED 61% HIGH 93% HIGH 100% HIGH 97%
KAVL MED 65% HIGH 100% HIGH 100% HIGH 97%
KHKY MED 73% HIGH 100% HIGH 100% MED 79%
KGMU MED 63% HIGH 93% HIGH 100% HIGH 100%
KAND MED 65% HIGH 93% HIGH 100% HIGH 100%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...LEV
NEAR TERM...MCAVOY
SHORT TERM...ARK
LONG TERM...ARK
AVIATION...MCAVOY
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
442 AM EDT THU MAY 30 2013
.SYNOPSIS...
HIGH PRESSURE CENTERED OVER THE ATLANTIC WILL KEEP US DRY WITH
TEMPERATURES SLIGHTLY ABOVE AVERAGE THROUGH THE END OF THE WEEK. THE
HIGH MOVES OFF THE ATLANTIC COAST OVER THE WEEKEND...AND A COLD
FRONT APPROACHES BY EARLY NEXT WEEK...RETURNING US TO AN UNSETTLED
PATTERN.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 440 AM EDT THURSDAY...MVFR CIGS ARE FILLING IN QUICKLY OVER NE
GA AND WE APPEAR TO BE ON TRACK FOR A STRATUS DECK TO INVADE THE
FORECAST AREA FROM THE SOUTHWEST OVER THE NEXT FEW HOURS. I DID
TWEAK SKY COVER TO ACCOUNT FOR CURRENT TRENDS...HOWEVER.
AS OF 300 AM EDT THURSDAY...MVFR LEVEL STRATUS IS EXPANDING ACROSS
SOUTHERN AND CENTRAL GA EARLY THIS THURSDAY MORNING. THE SREF SHOWS
A HIGH PROBABILITY THAT IT WILL CONTINUE TO EXPAND NORTH AND
NORTHEAST...EVENTUALLY SPREADING ACROSS NE GA...THE WRN UPSTATE AND
THE SRN NC MTNS. I/VE CARRIED MOSTLY CLOUDY SKIES EARLY IN THE DAY
TO ACCOUNT FOR THIS...BUT THE CLOUD LAYER SHOULD BE SHALLOW AND
SHOULD MIX INTO A CU FIELD FAIRLY QUICKLY BY LATE MORNING. OTHERWISE
IT WILL BE DRY ACROSS THE ENTIRE FORECAST AREA TODAY WITH MAX TEMPS
RUNNING ABOUT A CATEGORY ABOVE NORMAL.
WE WILL PROBABLY SEE STRATUS DEVELOP AGAIN TONIGHT. IN FACT...WITH
HIGHER BNDRY LAYER RH/S AND A STRONGER WIND FIELD...IT IS LIKELY TO
COVER MOST OF THE FORECAST AREA. STILL...IT/S NOT A GIVEN THAT THIS
WILL HAPPEN AND MY SKY COVER IS RATHER LOW...ESPECIALLY ACROSS WRN
NC.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 245 AM THURSDAY...UPPER RIDGE WILL BEGIN TO BREAK DOWN AND
SHIFT EAST FURTHER OFF THE ATLANTIC COAST DURING THE SHORT
TERM...BUT OVERALL WILL CONTINUE TO INFLUENCE OUR SENSIBLE WX. LLVL
FLOW WILL REMAIN LIGHT GENERALLY OUT OF THE S/SE OFF THE ATLANTIC.
MODELS IN BETTER AGREEMENT ON MORNING STRATUS DEVELOPING AND BEING A
LITTLE BIT MORE WIDESPREAD FRIDAY MORNING...BUT SHUD SCATTER OUT BY
MIDDAY. FCST SNDGS SHOW WEAK CAPE WITH INHIBITION FRI AFTN...SO
GOING WITH A DRY FCST.
ON SATURDAY...ONCE AGAIN...GUIDANCE INDICATING MORNING STRATUS
DEVELOPMENT...WITH INCREASE IN SOME MID-UPR MOISTURE AS WELL.
OVERALL...STILL LOOKS LIKE ANOTHER DRY DAY...ALTHO WILL KEEP A SLGT
CHC POP FOR THE NC MTNS...THANKS TO SOME INCREASED MOISTURE IN A
VEERING SWLY LLVL FLOW. HIGHS BOTH DAYS WILL BE SIMILAR TO LAST
COUPLE OF DAYS...ABOUT A CATEGORY OR TWO ABOVE NORMAL...WITH NEAR OR
SLIGHTLY ABOVE NORMAL OVERNIGHT LOWS.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
AS OF 300 AM THURSDAY...UNSETTLED WEATHER LOOKS TO RETURN THE CWFA
FOR SUNDAY INTO EARLY NEXT WEEK.
A COLD FRONT WILL APPROACH THE AREA FROM THE WEST ON SUNDAY...WITH A
PLUME OF DEEP RH AND HEIGHT FALLS ENTERING THE NC MTNS BY PEAK
HEATING. SO A SOLID CHC TO LOW-END LIKELY POPS FOR SUNDAY LOOKS
GOOD. CONVECTION MAY LINGER INTO THE NIGHT IN THE MOIST AIR MASS
WITH SOME UPR SUPPORT. THE FRONT IS PROGGED TO SETTLE ROUGHLY ALONG
THE BLUE RIDGE ON MONDAY...WITH PLENTY OF AFTN INSTBY ONCE AGAIN.
EXPECTING SCATTERED TO NUMEROUS SHWRS AND TSTMS TO
DEVELOP...POSSIBLY MOST FAVORED IN THE PIEDMONT ON WARM SIDE OF THE
FRONT. HIGHS WILL BE NEAR NORMAL BOTH DAYS...WITH SLIGHTLY ABOVE
NORMAL OVERNIGHT TEMPS.
THE FORECAST FOR TUESDAY AND WEDNESDAY WERE UNCHANGED...AS LATEST
MODEL TRENDS AND THE 00Z WPC GRIDS ARE IN LINE WITH EARLIER
THINKING. STILL EXPECTING THE FRONT TO SAG SE THRU THE CAROLINAS ON
TUESDAY...WITH A LINGERING CHC POP MAINLY SE OF I-85. THEN JUST A
SLGT CHC POP FOR MOST OF THE AREA ON WEDNESDAY...AS CANADIAN HIGH
PRES BUILDS IN ACRS THE GREAT LAKES TO THE SOUTHEAST STATES. TEMPS
WILL BE NEAR NORMAL.
&&
.AVIATION /09Z THURSDAY THROUGH MONDAY/...
AT KCLT...MODEL GUIDANCE AND PERSISTANCE FROM LAST NIGHT IMPLIES
THAT STRATUS WILL DEVELOP DOWN ACROSS THE MIDLANDS AND CLOSER TO THE
MOUNTAINS TOWARD MORNING. IT/S A TOUGH CALL...BUT KCLT MAY NOT
ACTUALLY SEE A CIG LATER TONIGHT. THEREFORE I/VE BACKED OFF THE BKN
CIG AND GONE SCT010 STARTING AT 10 UTC. THE NAM BUFKIT SOUNDINGS
APPEAR TO BE CAPPED AND NOT SUPPORTIVE OF A CU FIELD IN THE AFTN. I
THINK THAT/S A HAIR OVERDONE AND I DO KEEP FEW040 AROUND DURING THE
AFTN. WINDS WILL BE LIGHT OUT OF THE S TO SSW THROUGH THE DAY.
ELSEWHERE...PER THE SREF PROBS OF CIGS LOWER THAN 3KFT AND THE AREA
OF HIGHEST LLVL RH ON THE RUC AND PERSISTANCE WITH LAST NIGHT...WE
SHOULD SEE STRATUS DEVELOP OVER NORTH CENTRAL GA STARTING IN AN HOUR
OR TWO. IT SHOULD EXPAND NORTHEAST WITH TIME...AND SHOULD EVENTUALLY
WORK ACROSS THE UPSTATE TAF SITES. EXACTLY WHEN THIS HAPPENS ISN/T
AN EASY CALL. FOR NOW I HAVE MVFR CIGS DEVELOPING AT 10 UTC AT KAND
AND NOT TIL 12 UTC AT KGSP. HOPEFULLY THAT WILL BE CLOSE. I/M LESS
CONFIDENT OF STRATUS AT KAVL OR KHKY AND I HAVEN/T CARRIED ANYTHING
AT THOSE SITES. CIGS WILL GRADUALLY LIFT AND MIX OUT DURING THE
COURSE OF THE MORNING. OTHERWISE WINDS WILL BE OUT OF THE S TO SSW
AGAIN TODAY AT SPEEDS UNDER 10 KTS.
OUTLOOK...GENERALLY FAIR CONDITIONS ARE EXPECTED THROUGH SATURDAY.
HOWEVER...RESTRICTIONS FROM MORNING STRATUS...AND POSSIBLY
FOG...WILL CONTINUE EACH MORNING THRU SUNDAY. CHANCES FOR MAINLY
AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS WILL INCREASE
SIGNIFICANTLY BY SUNDAY AFTERNOON...AS A COLD FRONT APPROACHES FROM
THE TN VALLEY.
CONFIDENCE TABLE...
08-14Z 14-20Z 20-02Z 02-08Z
KCLT HIGH 93% HIGH 93% HIGH 100% HIGH 100%
KGSP HIGH 87% HIGH 80% HIGH 100% HIGH 100%
KAVL HIGH 98% HIGH 100% HIGH 100% HIGH 95%
KHKY HIGH 100% HIGH 100% HIGH 100% HIGH 90%
KGMU HIGH 87% HIGH 80% HIGH 100% HIGH 100%
KAND HIGH 81% HIGH 81% HIGH 100% HIGH 100%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...LEV
NEAR TERM...MCAVOY
SHORT TERM...ARK
LONG TERM...ARK
AVIATION...MCAVOY
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
318 AM EDT THU MAY 30 2013
.SYNOPSIS...
HIGH PRESSURE CENTERED OVER THE ATLANTIC WILL KEEP US DRY WITH
TEMPERATURES SLIGHTLY ABOVE AVERAGE THROUGH THE END OF THE WEEK. THE
HIGH MOVES OFF THE ATLANTIC COAST OVER THE WEEKEND...AND A COLD
FRONT APPROACHES BY EARLY NEXT WEEK...RETURNING US TO AN UNSETTLED
PATTERN.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 300 AM EDT THURSDAY...MVFR LEVEL STRATUS IS EXPANDING ACROSS
SOUTHERN AND CENTRAL GA EARLY THIS THURSDAY MORNING. THE SREF SHOWS
A HIGH PROBABILITY THAT IT WILL CONTINUE TO EXPAND NORTH AND
NORTHEAST...EVENTUALLY SPREADING ACROSS NE GA...THE WRN UPSTATE AND
THE SRN NC MTNS. I/VE CARRIED MOSTLY CLOUDY SKIES EARLY IN THE DAY
TO ACCOUNT FOR THIS...BUT THE CLOUD LAYER SHOULD BE SHALLOW AND
SHOULD MIX INTO A CU FIELD FAIRLY QUICKLY BY LATE MORNING. OTHERWISE
IT WILL BE DRY ACROSS THE ENTIRE FORECAST AREA TODAY WITH MAX TEMPS
RUNNING ABOUT A CATEGORY ABOVE NORMAL.
WE WILL PROBABLY SEE STRATUS DEVELOP AGAIN TONIGHT. IN FACT...WITH
HIGHER BNDRY LAYER RH/S AND A STRONGER WIND FIELD...IT IS LIKELY TO
COVER MOST OF THE FORECAST AREA. STILL...IT/S NOT A GIVEN THAT THIS
WILL HAPPEN AND MY SKY COVER IS RATHER LOW...ESPECIALLY ACROSS WRN
NC.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 245 AM THURSDAY...UPPER RIDGE WILL BEGIN TO BREAK DOWN AND
SHIFT EAST FURTHER OFF THE ATLANTIC COAST DURING THE SHORT
TERM...BUT OVERALL WILL CONTINUE TO INFLUENCE OUR SENSIBLE WX. LLVL
FLOW WILL REMAIN LIGHT GENERALLY OUT OF THE S/SE OFF THE ATLANTIC.
MODELS IN BETTER AGREEMENT ON MORNING STRATUS DEVELOPING AND BEING A
LITTLE BIT MORE WIDESPREAD FRIDAY MORNING...BUT SHUD SCATTER OUT BY
MIDDAY. FCST SNDGS SHOW WEAK CAPE WITH INHIBITION FRI AFTN...SO
GOING WITH A DRY FCST.
ON SATURDAY...ONCE AGAIN...GUIDANCE INDICATING MORNING STRATUS
DEVELOPMENT...WITH INCREASE IN SOME MID-UPR MOISTURE AS WELL.
OVERALL...STILL LOOKS LIKE ANOTHER DRY DAY...ALTHO WILL KEEP A SLGT
CHC POP FOR THE NC MTNS...THANKS TO SOME INCREASED MOISTURE IN A
VEERING SWLY LLVL FLOW. HIGHS BOTH DAYS WILL BE SIMILAR TO LAST
COUPLE OF DAYS...ABOUT A CATEGORY OR TWO ABOVE NORMAL...WITH NEAR OR
SLIGHTLY ABOVE NORMAL OVERNIGHT LOWS.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
AS OF 300 AM THURSDAY...UNSETTLED WEATHER LOOKS TO RETURN THE CWFA
FOR SUNDAY INTO EARLY NEXT WEEK.
A COLD FRONT WILL APPROACH THE AREA FROM THE WEST ON SUNDAY...WITH A
PLUME OF DEEP RH AND HEIGHT FALLS ENTERING THE NC MTNS BY PEAK
HEATING. SO A SOLID CHC TO LOW-END LIKELY POPS FOR SUNDAY LOOKS
GOOD. CONVECTION MAY LINGER INTO THE NIGHT IN THE MOIST AIR MASS
WITH SOME UPR SUPPORT. THE FRONT IS PROGGED TO SETTLE ROUGHLY ALONG
THE BLUE RIDGE ON MONDAY...WITH PLENTY OF AFTN INSTBY ONCE AGAIN.
EXPECTING SCATTERED TO NUMEROUS SHWRS AND TSTMS TO
DEVELOP...POSSIBLY MOST FAVORED IN THE PIEDMONT ON WARM SIDE OF THE
FRONT. HIGHS WILL BE NEAR NORMAL BOTH DAYS...WITH SLIGHTLY ABOVE
NORMAL OVERNIGHT TEMPS.
THE FORECAST FOR TUESDAY AND WEDNESDAY WERE UNCHANGED...AS LATEST
MODEL TRENDS AND THE 00Z WPC GRIDS ARE IN LINE WITH EARLIER
THINKING. STILL EXPECTING THE FRONT TO SAG SE THRU THE CAROLINAS ON
TUESDAY...WITH A LINGERING CHC POP MAINLY SE OF I-85. THEN JUST A
SLGT CHC POP FOR MOST OF THE AREA ON WEDNESDAY...AS CANADIAN HIGH
PRES BUILDS IN ACRS THE GREAT LAKES TO THE SOUTHEAST STATES. TEMPS
WILL BE NEAR NORMAL.
&&
.AVIATION /07Z THURSDAY THROUGH MONDAY/...
AT KCLT...MODEL GUIDANCE AND PERSISTANCE FROM LAST NIGHT IMPLIES
THAT STRATUS WILL DEVELOP DOWN ACROSS THE MIDLANDS AND CLOSER TO THE
MOUNTAINS TOWARD MORNING. IT/S A TOUGH CALL...BUT KCLT MAY NOT
ACTUALLY SEE A CIG LATER TONIGHT. THEREFORE I/VE BACKED OFF THE BKN
CIG AND GONE SCT010 STARTING AT 10 UTC. THE NAM BUFKIT SOUNDINGS
APPEAR TO BE CAPPED AND NOT SUPPORTIVE OF A CU FIELD IN THE AFTN. I
THINK THAT/S A HAIR OVERDONE AND I DO KEEP FEW040 AROUND DURING THE
AFTN. WINDS WILL BE LIGHT OUT OF THE S TO SSW THROUGH THE DAY.
ELSEWHERE...PER THE SREF PROBS OF CIGS LOWER THAN 3KFT AND THE AREA
OF HIGHEST LLVL RH ON THE RUC AND PERSISTANCE WITH LAST NIGHT...WE
SHOULD SEE STRATUS DEVELOP OVER NORTH CENTRAL GA STARTING IN AN HOUR
OR TWO. IT SHOULD EXPAND NORTHEAST WITH TIME...AND SHOULD EVENTUALLY
WORK ACROSS THE UPSTATE TAF SITES. EXACTLY WHEN THIS HAPPENS ISN/T
AN EASY CALL. FOR NOW I HAVE MVFR CIGS DEVELOPING AT 10 UTC AT KAND
AND NOT TIL 12 UTC AT KGSP. HOPEFULLY THAT WILL BE CLOSE. I/M LESS
CONFIDENT OF STRATUS AT KAVL OR KHKY AND I HAVEN/T CARRIED ANYTHING
AT THOSE SITES. CIGS WILL GRADUALLY LIFT AND MIX OUT DURING THE
COURSE OF THE MORNING. OTHERWISE WINDS WILL BE OUT OF THE S TO SSW
AGAIN TODAY AT SPEEDS UNDER 10 KTS.
OUTLOOK...GENERALLY FAIR CONDITIONS ARE EXPECTED THROUGH SATURDAY.
HOWEVER...RESTRICTIONS FROM MORNING STRATUS...AND POSSIBLY
FOG...WILL CONTINUE EACH MORNING THRU SUNDAY. CHANCES FOR MAINLY
AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS WILL INCREASE
SIGNIFICANTLY BY SUNDAY AFTERNOON...AS A COLD FRONT APPROACHES FROM
THE TN VALLEY.
CONFIDENCE TABLE...
07-13Z 13-19Z 19-01Z 01-07Z
KCLT HIGH 100% HIGH 85% HIGH 100% HIGH 100%
KGSP HIGH 96% MED 72% HIGH 100% HIGH 100%
KAVL HIGH 96% HIGH 100% HIGH 100% HIGH 97%
KHKY HIGH 100% HIGH 100% HIGH 100% HIGH 94%
KGMU HIGH 96% MED 72% HIGH 100% HIGH 100%
KAND HIGH 89% MED 76% HIGH 100% HIGH 100%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...LEV
NEAR TERM...MCAVOY
SHORT TERM...ARK
LONG TERM...ARK
AVIATION...MCAVOY
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
131 AM EDT THU MAY 30 2013
.SYNOPSIS...
HIGH PRESSURE CENTERED OVER THE ATLANTIC WILL KEEP US DRY WITH
TEMPERATURES SLIGHTLY ABOVE AVERAGE THROUGH THE END OF THE WEEK. THE
HIGH MOVES OFF THE ATLANTIC COAST OVER THE WEEKEND... AND A COLD
FRONT APPROACHES BY EARLY NEXT WEEK... RETURNING US TO AN UNSETTLED
PATTERN.
&&
.NEAR TERM /THROUGH TODAY/...
AS OF 0130 AM EDT THURSDAY...SCT TO BKN STRATO-CU CONTINUE TO
DEVELOP ALONG THE BLUE RIDGE. UPPED SKY COVER TO ACCOUNT FOR THAT.
BASED ON THE SREF...RUC AND PERSISTENCE WITH LAST NIGHT I/VE UPPED
SKY COVER TOWARD MORNING AND BROUGHT A STRATUS DECK ACROSS NE
GA...THE NORTHERN AND WRN UPSTATE AND THE SRN NC MTNS...SOUTH OF
ASHEVILLE.
AS OF MID EVENING...FORECAST LOOKS LIKE IT IS IN GOOD SHAPE. NO
CHANGES PLANNED.
REMAINDER OF PREVIOUS DISCUSSION...
CLOUDS SHUD DIMINISH THIS EVENING WITH LOSS OF HEATING. EXPECT
ANOTHER ROUND OF LOW CLOUDS TO DEVELOP ACROSS THE SRN AND WRN CWFA
NEAR DAYBREAK GIVEN THE CONTINUED MOIST SLY LOW LEVEL FLOW AND
SUBSIDENCE INVERSION. EXPECT MOST OF THE NC PIEDMONT TO ONLY SEE SCT
CLOUDS BY MORNING...BUT THE CLOUDY SKIES COULD CREEP FARTHER NORTH.
THE CLOUDS SHUD SLOWLY LIFT AND SCATTER OUT THRU THE MORNING THU
WITH MOSTLY SUNNY SKIES EXPECTED FOR AFTERNOON. WITH RIDGING SFC AND
ALOFT...AND ASSOCIATED SUBSIDENCE INVERSION... REMAINING IN PLACE
ACROSS THE AREA THU...DO NOT EXPECT ANY DEEP CONVECTION TO DEVELOP
DURING THE AFTERNOON...EVEN OVER THE MTNS. LOWS TONIGHT SHUD BE NEAR
TO SLIGHTLY ABOVE NORMAL. HIGHS THU SHUD RISE TO AS MUCH AS 5
DEGREES ABOVE NORMAL.
&&
.SHORT TERM /TONIGHT THROUGH SATURDAY/...
AS OF 205 PM WEDNESDAY...UPPER RIDGE WILL REMAIN CENTERED/SITUATED
IN THE VICINITY OF THE VA COAST WITH ONLY A SLOW TRANSITION TO THE
EAST THROUGH SAT. AT THE SURFACE...THE BURMUDA HIGH WILL REMAIN
RIDGED WESTWARD INTO THE SE U.S.. THEREFORE...GENERALLY DRY AND VERY
WARM WEATHER WILL CONTINUE IN THE SHORT TERM. MODELS ARE GENERALLY
LACKING IN QPF RESPONSE THU NIGHT THRU SAT. THIS MAKES SENSE IN
THAT FCST SNDGS CONTINUE TO FEATURE A SUBSIDENCE INVERSION. THE
EXCEPTION TO THE GENERAL LACK OF CONVECTION MAY BE FRI EVENING OVER
THE MOUNTAINS AS MODEL TIME HEIGHTS SHOW LOW LEVEL MOISTURE
INCREASING DUE TO THE SE FLOW OFF THE ATLANTIC WHICH MAY ALLOW
PARCELS TO OVERCOME THE CAP IN UPSLOPE AREAS. HENCE...HAVE SOME
ISOLATED/WIDELY SCT POPS FRI NIGHT IN THE MOUNTAINS TO ACCOUNT FOR
THIS. A FEW ISOLD CELLS CANNOT BE RULED OUT IN THE MTNS AGAIN SAT
AFTERNOON.. HIGHS WILL CONTINUE TO BE A CATEORY OR TWO ABOVE NORMAL
BOTH DAYS. OVERNIGHT LOWS WILL BE QUITE MILD AS THE MOIST/PERSISTENT
SELY FLOW OFF THE ATLANTIC IS LIKELY TO PRODUCE SOME MORNING STRATUS
BOTH FRI AND SAT MORNINGS. THIS IS MOST LIKELY TO OCCUR IN THE
WESTERN HALF OF THE CWFA. ANY LOW CLOUDS SHUD QUICKLY SCATTER OUT BY
MIDDAY BOTH DAYS.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
AS OF 200 PM WEDNESDAY...LOOKS LIKE AN ACTIVE PATTERN WILL BE
IN PLAY OVER THE EXT RANGE. THE LATEST OP MODELS AGREE DECENTLY WITH
THE ULVL FLOW AND UPSTREAM TROF CONFIG BEGINNING THE PERIOD AND WITH
THE GENERAL PROPAGATION AND STRENGTH OF THE SYNOPTIC WAVE EASTWARD.
THERE ARE ENOUGH DIFFERENCES IN THE DETAILS HOWEVER TO HAVE MODERATE
OR A BIT LOWER CONFIDENCE IN THE SENSIBLE WX OVER THE PERIOD. THE
12Z GFS IS A SLOWER OUTLIER AND THE GEFS MEAN GIVES SUPPORT TO THE
QUICKER ECMWF...THUS A BLEND OF THE OP MODELS AND WPC GUIDANCE WAS
USED FOR OVERALL TIMING AND THE WEAKENING TROF.
THE PERIOD BEGINS WITH MOIST ATL FLOW CONTINUING ACROSS THE REGION
AND A FEW UPSLOPE -SHRA/TSTMS SHOULD BE WANING THROUGH SAT NIGHT. AS
THE UPPER TROF IMPINGES...ULVL DIV WILL INCREASE AND AIDE IN THUNDER
ACTIVITY SUN AFTERNOON. NOT MUCH OF A DISTINCT SFC CONVERGENCE ZONE
IS NOTED...SO WILL EXPECT MOST OF THE ACTIVITY ACROSS THE NC MTNS
WHERE LIKELY POPS HAVE BEEN INTRODUCED. SOUNDINGS SHOW A DEEP
CONVECTIVE POTENTIAL WITH LOW END SBCAPE DEVELOPING AS THE WEAKENING
ULVL VORT WAVE CROSSES OVERHEAD. SO...EXPECT PRETTY GOOD COVERAGE IN
THE MTNS...WITH ISOL/SCT STORMS DEVELOPING TO THE EAST THROUGH THE
AFTERNOON....THEN LIKELY COVERAGE MOST LOCALES AS THE WAVE MOVES
EAST OVERNIGHT. THERE REMAINS A FAIR AMOUNT OF UNCERTAINTY MON WRT
TO THE FRONTAL PLACEMENT...AND WILL COUNT THE FRONT JUST MOVING INTO
THE MTNS BY MID DAY. SO...ANOTHER DAY OF GOOD HEATING AND
INSTABILITY WILL GENERATE TSTMS. THE GFS SLOWS THE FRONT DOWN AS IT
LOSES MUCH ULVL SUPPORT AND KEEPS THINGS ACTIVE MON NIGHT INTO
TUE...WHILE THE ECMWF AND THE WPC HAVE THE FRONT NEAR THE ATL COAST
BY 12Z TUE. WITH THIS MUCH UNCERTAINTY...HAVE ALIGNED CHANCE POPS TO
FAVOR THE ERN ZONES LATE MON THROUGH TUE. THERE IS GOOD AGREEMENT
WITH A MOIST WEDGE DEVELOPING TUE NIGHT AND PERSISTING THROUGH TH
PERIOD. THIS WOULD KEEP MAX TEMPS A CAT OR SO BELOW NORMAL WED AND
POSSIBLY THU. MAX TEMPS SUN THROUGH TUE SHOULD BE A FEW DEGREES ABOVE
NORMAL WITH WARM SECTOR FLOW REMAINING OVER THE REGION. WITH ALL THE
NOCTURNAL CLOUDINESS EXPECTED...MINS SHOULD ALSO BE A COUPLE DEGREES
ABOVE NORMAL THROUGH TUE MORNING BEFORE THE WEDGE BUILDS IN.
&&
.AVIATION /06Z THURSDAY THROUGH MONDAY/...
AT KCLT...MODEL GUIDANCE AND PERSISTANCE FROM LAST NIGHT IMPLIES
THAT STRATUS WILL DEVELOP DOWN ACROSS THE MIDLANDS AND CLOSER TO THE
MOUNTAINS TOWARD MORNING. IT/S A TOUGH CALL...BUT KCLT MAY NOT
ACTUALLY SEE A CIG LATER TONIGHT. THEREFORE I/VE BACKED OFF THE BKN
CIG AND GONE SCT010 STARTING AT 10 UTC. THE NAM BUFKIT SOUNDINGS
APPEAR TO BE CAPPED AND NOT SUPPORTIVE OF A CU FIELD IN THE AFTN. I
THINK THAT/S A HAIR OVERDONE AND I DO KEEP FEW040 AROUND DURING THE
AFTN. WINDS WILL BE LIGHT OUT OF THE S TO SSW THROUGH THE DAY.
ELSEWHERE...PER THE SREF PROBS OF CIGS LOWER THAN 3KFT AND THE AREA
OF HIGHEST LLVL RH ON THE RUC AND PERSISTANCE WITH LAST NIGHT...WE
SHOULD SEE STRATUS DEVELOP OVER NORTH CENTRAL GA STARTING IN AN HOUR
OR TWO. IT SHOULD EXPAND NORTHEAST WITH TIME...AND SHOULD EVENTUALLY
WORK ACROSS THE UPSTATE TAF SITES. EXACTLY WHEN THIS HAPPENS ISN/T
AN EASY CALL. FOR NOW I HAVE MVFR CIGS DEVELOPING AT 10 UTC AT KAND
AND NOT TIL 12 UTC AT KGSP. HOPEFULLY THAT WILL BE CLOSE. I/M LESS
CONFIDENT OF STRATUS AT KAVL OR KHKY AND I HAVEN/T CARRIED ANYTHING
AT THOSE SITES. CIGS WILL GRADUALLY LIFT AND MIX OUT DURING THE
COURSE OF THE MORNING. OTHERWISE WINDS WILL BE OUT OF THE S TO SSW
AGAIN TODAY AT SPEEDS UNDER 10 KTS.
OUTLOOK...GENERALLY FAIR CONDITIONS ARE EXPECTED THROUGH SATURDAY.
HOWEVER...RESTRICTIONS FROM MORNING STRATUS...AND POSSIBLY
FOG...WILL CONTINUE EACH MORNING THRU SUNDAY. CHANCES FOR MAINLY
AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS WILL INCREASE
SIGNIFICANTLY BY SUNDAY AFTERNOON...AS A COLD FRONT APPROACHES FROM
THE TN VALLEY.
CONFIDENCE TABLE...
05-11Z 11-17Z 17-23Z 23-05Z
KCLT HIGH 100% HIGH 85% HIGH 100% HIGH 100%
KGSP HIGH 100% MED 73% HIGH 100% HIGH 100%
KAVL HIGH 97% HIGH 94% HIGH 100% HIGH 100%
KHKY HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KGMU HIGH 100% MED 73% HIGH 100% HIGH 100%
KAND HIGH 100% MED 72% HIGH 100% HIGH 100%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...LEV
NEAR TERM...MCAVOY
SHORT TERM...LG
LONG TERM...SBK
AVIATION...MCAVOY
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
1240 PM CDT THU MAY 30 2013
.UPDATE...
ISSUED AT 1127 AM CDT THU MAY 30 2013
WINDS IN NORTHEAST NEBRASKA INTO SOUTHEAST SOUTH DAKOTA AND NORTHWEST
IOWA REMAIN PRIMARILY SOUTHWEST THIS MORNING KEEPING A RELATIVELY DRY
LOW TO MID LEVELS UPSTREAM. WINDS ARE EXPECTED TO BACK A BIT THIS
AFTERNOON WITH THE ARRIVAL OF THE SURFACE TROUGH CURRENTLY SWINGING
THROUGH SOUTH CENTRAL SOUTH DAKOTA. WITH DAYTIME HEATING EARLY THIS
AFTERNOON...SHOWERS AND THUNDERSTORMS SHOULD REDEVELOP ACROSS THE
AREA AND TRACK EASTWARD. SHEAR IS NOT VERY IMPRESSIVE AT THIS
POINT...BUT THE LATEST RAP FORECAST SOUNDINGS SUGGEST THAT WE MAY
DESTABILIZE ENOUGH FOR SOME NARROW CAPE VALUES APPROACHING 1000 J/KG
BY LATE AFTERNOON. CANNOT RULE OUT THE POTENTIAL FOR A FEW MARGINALLY
SEVERE STORMS THIS AFTERNOON AND EVENING IN FAR SOUTHEAST SOUTH
DAKOTA AND NORTHWEST IOWA...WHERE MUCH MORE FAVORABLE SHEAR IS
EXPECTED TO SET UP AND MOISTURE IS MORE FAVORABLE WITH SOUTHERLY
WINDS. THE MAIN THREAT WITH STRONG TO SEVERE STORMS WILL BE DIME TO
QUARTER- SIZE HAIL. SEVERE OUTLOOK HOWEVER IS VERY CONDITIONAL AND
OVERALL NOT VERY IMPRESSIVE. MADE A QUICK UPDATE TO REMOVE POPS THIS
MORNING AND ADJUST CLOUDS SLIGHTLY. EVERYTHING ELSE IS ON TRACK.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 359 AM CDT THU MAY 30 2013
WILL GO AHEAD AND CANCEL THE FLASH FLOOD WATCH FOR OUR
SOUTHEASTERN ZONES. REMNANTS OF LIGHT TO SPOTTY MODERATE RAINFALL
ARE MOVING NORTHWARD AT THIS TIME EAST OF I 29...BUT IT IS NOT
ENOUGH TO EXAGGERATE ANY EXISTING FLOODING PROBLEMS. IT IS LIKELY
THAT THE HEAVIEST RAINFALL FOR TODAY WILL ALSO STAY TO THE SOUTH
OF THE SIOUX FALLS FORECAST AREA. SYNOPTIC SITUATION SHOWS A HUGE
UPPER LOW IN TWO PIECES...GENERALLY EXTENDING FROM OFF THE BRITISH
COLUMBIA COAST TO THE NORTHWESTERN PLAINS. LARGE AREA OF SURFACE
LOW PRESSURE FOLLOWS SUIT AND IS SITUATED OVER CENTRAL SD...WITH
TROUGHING NUDGING DOWN INTO THE CENTRAL PLAINS. ANOTHER SURFACE LOW
IS SITUATED OVER THE OKLAHOMA PANHANDLE...WHICH IS THE RESULT OF A
VERY STRONG SHORTWAVE MOVING EASTWARD FROM THAT AREA TODAY...INTO
KANSAS...MISSOURI...SOUTHERN IOWA AREAS. THERE IS A LOT OF MODEL
CONSENSUS THAT THE HEAVIER RAIN WILL BE CONFINED TO THAT SHORT
WAVE AND SOUTH OF OUR AREA.
SO FROM HERE AND OUT...WE ARE MAINLY LEFTOVER WITH ISOLATED TO
SCATTERED INSTABILITY SHOWERS AND A FEW POSSIBLE THUNDERSTORMS...
ESPECIALLY THIS AFTERNOON. WENT DRY FOR OUR WESTERN ZONES THIS
MORNING AS THERE IS SIMPLY NO SIGN OF CONVECTIVE REDEVELOPMENT YET
IN CENTRAL NEB. THE 850MB STREAMLINES PRETTY MUCH TELL THE STORY
FOR NOW...IN THAT THEY ARE WRAPPING FROM A WESTERLY DIRECTION
UNDERNEATH THE AFOREMENTIONED LOW...COMING OUT OF WESTERN AND
CENTRAL NEBRASKA AND INTO OUR WESTERN ZONES. SO THE MOIST LOW
LEVEL FLOW IS CUTOFF IN OUR WEST. ALONG AND EAST OF I 29...THE LOW
LEVEL JET STILL EXISTS BUT IS WEAKER THEN YESTERDAY. ML CAPE IS
PRETTY ANEMIC THIS MORNING...BUT DOES INCREASE THIS AFTERNOON AS
ANY CLEARING WILL HELP TO HEAT THINGS OUT. IN ADDITION...SOME OF
THE HIGHER RESOLUTION MODELS ARE STRONGLY HINTING AT THE SURFACE
TROUGH MOVING EASTWARD INTO THE JAMES RIVER VALLEY THIS
AFTERNOON...WITH A DRY LINE PRESSING THROUGH OUR SOUTH CENTRAL SD
ZONES. THE TROUGH MAY PROVIDE A FOCUS FOR SCATTERED SHOWERS AND
STORMS ALONG AN AXIS FROM YANKTON TO SIOUX FALLS AND VICINITIES...
HELPED BY STRONGLY VEERING PROFILES JUST AHEAD OF THE DRY LINE.
ELSEWHERE AS THE AFTERNOON PROGRESSES...POPCORN TYPE INSTABILITY
SHOWERS AND THUNDERSTORMS SHOULD DOMINATE THIS AREA OF THE
SCATTERED VARIETY. SO VERY MUCH A NUISANCE SITUATION. HIGHS TODAY
STILL LOOK LIKE WIDESPREAD 70S...WHICH SHOULD BE ENOUGH TO PROVIDE
SOME AFTERNOON INSTABILITY.
FOR TONIGHT...ONCE THE HEATING SUBSIDES...SO WILL OUR CHANCE FOR
INSTABILITY RAINFALL. BUT LATE TONIGHT...THE UPPER LOW BEGINS TO
WRAP IN A CHANCE FOR SHOWERS INTO OUR NORTHWEST AREAS. MOISTURE
PROFILES IN THAT AREA ARE QUITE HIGH BY LATE TONIGHT...WITH DRY
SLOTTING TAKING OVER AFTER MIDNIGHT FOR THE REST OF OUR FORECAST
AREA.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 359 AM CDT THU MAY 30 2013
ON FRIDAY AND SATURDAY...OUR WEATHER WILL CONTINUE TO BE DOMINATED
BY THE UPPER LOW. IT WILL STILL BE CLOSED ON FRIDAY AS IT MOVES
SLOWLY EASTWARD. THEN IT WILL BECOME A TROUGH ON SATURDAY AS IT
MOVES INTO THE NORTHERN MISSISSIPPI VALLEY. PV IS VERY STRONG ON
THE NORTH AND WEST SIDES OF THE UPPER LOW...ALONG WITH STRONG
TROWALING CLEARLY EVIDENT AT THE MID LEVELS. ALL OF THIS IS
CAUSING A HIGH MOISTURE PROFILE WHICH MOVES SOUTHEASTWARD...SO
EXPECT LIGHT SHOWERS LIKELY TO MOVE IN THAT DIRECTION THROUGH
TIME AND EVENTUALLY ENCOMPASSING ALMOST THE ENTIRE WESTERN HALF OF
OUR FORECAST AREA. MODELS ARE CERTAINLY SHOWING QUITE A CONVEYOR
BELT OF PRECIPITATION...MOVING NORTHEASTWARD AHEAD OF THE LOW FROM
THE SOUTHERN PLAINS INTO THE GREAT LAKES...THEN LIGHT RAIN ARCHING
BACK THROUGH PARTS OF THE NORTHERN AND WESTERN PLAINS ALONG THE
TROWALING.
ANOTHER THING TO WATCH FOR FRIDAY AFTERNOON...IS THAT THE LEADING
EDGE OF THE COLD FRONT COULD SPARK SOME SCATTERED THUNDERSTORMS
ALONG AND SOUTH OF A SIOUX CITY TO WINDOM MN LINE. DO NOT THINK
THE COVERAGE OF STORMS WILL BE ALL THAT GREAT...AND ALMOST WENT
ISOLATED. BUT AGAIN SOMETHING TO WATCH FOR.
THIS COLD FRONT MOVES EASTWARD AND WILL GIVE OUR FORECAST AREA
SOME VERY CHILLY AIR TO CONTEND WITH ON SATURDAY. SATURDAY DOES
NOT LOOK LIKE A PLEASANT DAY...AS EVEN IF LIGHT SHOWERS DO NOT OCCUR
AT YOUR LOCATION...IT WILL BE CONSIDERABLY CLOUDY AND WINDY ALONG
WITH THE VERY CHILLY TEMPERATURES. RECORD LOW HIGHS ON JUNE 1 ARE
QUITE A BIT COLDER THAN WHAT WE HAVE FORECAST HOWEVER...SO THEY
SHOULD NOT BE IN JEOPARDY OF FALLING. SOME OF THE LIGHT SHOWERS BY
SATURDAY AFTERNOON WILL BE THE RESULT OF WHAT HEATING THERE IS.
THEREFORE BY SATURDAY NIGHT...ELIMINATED ALL POPS IN OUR EASTERN
ZONES. CONCERNING TEMPERATURES...COOLED OFF OUR WESTERN ZONES A
FAIR AMOUNT ON FRIDAY BEHIND THE COLD FRONT...NOTING THE CLOUDY
AND SHOWERY CONDITIONS.
THE SUNDAY THROUGH WEDNESDAY PERIOD WILL START DRY AND COOL
SUNDAY...BUT THE COOL WILL FEEL NICE WITH LIGHT TO MODERATE
NORTHERLY WINDS BEGINNING TO TURN EASTERLY AS SURFACE RIDGE PASSES
BY TO THE NORTH. WAS LOOKING FOR MONDAY TO BE DRY AND A LITTLE
WARMER...BUT IT LOOKS LIKE SOUTHEASTERLY THERMAL LIFT PATTERN WILL
DEVELOP SOON ENOUGH TO MENTION A SMALL CHANCE OF STORMS. THIS CHANCE
SHOULD BE SOMEWHAT BIGGER FOR THE REST OF THE PERIOD...MONDAY NIGHT
INTO WEDNESDAY...AS UPPER WAVE DIGS FROM SOUTHWEST CANADA INTO
THE DAKOTAS. WILL GO WITH GUIDANCE KEEPING TEMPERATURES FAIRLY
CLOSE TO SEASONAL FOR NOW...THIS SEEMS IN LINE WITH THE NEW ECMWF.
THE GFS WOULD SUGGEST COOLER BY WEDNESDAY. SINCE NO TREND IS SEEN
AS TO WHICH MODEL IS BETTER THAT FAR AHEAD...GUIDANCE AND
CONSISTENCY WIN FOR NOW. FOR THE MOMENT DO NOT EXPECT MOISTURE
INFLOW TO BE ENOUGH FOR SEVERE STORMS OR HEAVY RAIN...BUT MID AND
UPPER FLOW WILL BE MORE THAN AMPLE SO WILL HAVE TO BE OPEN TO
POSSIBLE CHANGE OF THINKING IN COMING DAYS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1233 PM CDT THU MAY 30 2013
VFR CONDITIONS WILL BE PREDOMINATE FOR MOST AREAS...HOWEVER BRIEF
DIPS TO 1500 TO 3000 FEET IN SCATTERED SHOWERS AND THUNDERSTORMS WILL
BE POSSIBLE THROUGH AROUND 03Z FRIDAY. LEFT OUT MENTION OF SHOWERS
AND THUNDERSTORMS IN TAFS AS ACTIVITY WILL BE VERY SPOTTY AND LIKELY
VERY BRIEF. THE FAR NORTHWEST CORNER OF THE FORECAST AREA...INCLUDING
KHON COULD DROP TO MORE PREDOMINATE MVFR CEILINGS AFTER 09Z...BUT
GUIDANCE REMAINS A BIT UNCERTAIN WITH THE TIMING OF THESE LOWER
CEILINGS. WINDS WILL ALSO TURN MORE SOUTHWESTERLY TONIGHT AND BECOME
BREEZY DURING THE DAYLIGHT HOURS.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
UPDATE...
SHORT TERM...MJF
LONG TERM...MJF/WILLIAMS
AVIATION...
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
1127 AM CDT THU MAY 30 2013
.UPDATE...
ISSUED AT 1127 AM CDT THU MAY 30 2013
WINDS IN NORTHEAST NEBRASKA INTO SOUTHEAST SOUTH DAKOTA AND NORTHWEST
IOWA REMAIN PRIMARILY SOUTHWEST THIS MORNING KEEPING A RELATIVELY DRY
LOW TO MID LEVELS UPSTREAM. WINDS ARE EXPECTED TO BACK A BIT THIS
AFTERNOON WITH THE ARRIVAL OF THE SURFACE TROUGH CURRENTLY SWINGING
THROUGH SOUTH CENTRAL SOUTH DAKOTA. WITH DAYTIME HEATING EARLY THIS
AFTERNOON...SHOWERS AND THUNDERSTORMS SHOULD REDEVELOP ACROSS THE
AREA AND TRACK EASTWARD. SHEAR IS NOT VERY IMPRESSIVE AT THIS
POINT...BUT THE LATEST RAP FORECAST SOUNDINGS SUGGEST THAT WE MAY
DESTABILIZE ENOUGH FOR SOME NARROW CAPE VALUES APPROACHING 1000 J/KG
BY LATE AFTERNOON. CANNOT RULE OUT THE POTENTIAL FOR A FEW MARGINALLY
SEVERE STORMS THIS AFTERNOON AND EVENING IN FAR SOUTHEAST SOUTH
DAKOTA AND NORTHWEST IOWA...WHERE MUCH MORE FAVORABLE SHEAR IS
EXPECTED TO SET UP AND MOISTURE IS MORE FAVORABLE WITH SOUTHERLY
WINDS. THE MAIN THREAT WITH STRONG TO SEVERE STORMS WILL BE DIME TO
QUARTER- SIZE HAIL. SEVERE OUTLOOK HOWEVER IS VERY CONDITIONAL AND
OVERALL NOT VERY IMPRESSIVE. MADE A QUICK UPDATE TO REMOVE POPS THIS
MORNING AND ADJUST CLOUDS SLIGHTLY. EVERYTHING ELSE IS ON TRACK.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 359 AM CDT THU MAY 30 2013
WILL GO AHEAD AND CANCEL THE FLASH FLOOD WATCH FOR OUR
SOUTHEASTERN ZONES. REMNANTS OF LIGHT TO SPOTTY MODERATE RAINFALL
ARE MOVING NORTHWARD AT THIS TIME EAST OF I 29...BUT IT IS NOT
ENOUGH TO EXAGGERATE ANY EXISTING FLOODING PROBLEMS. IT IS LIKELY
THAT THE HEAVIEST RAINFALL FOR TODAY WILL ALSO STAY TO THE SOUTH
OF THE SIOUX FALLS FORECAST AREA. SYNOPTIC SITUATION SHOWS A HUGE
UPPER LOW IN TWO PIECES...GENERALLY EXTENDING FROM OFF THE BRITISH
COLUMBIA COAST TO THE NORTHWESTERN PLAINS. LARGE AREA OF SURFACE
LOW PRESSURE FOLLOWS SUIT AND IS SITUATED OVER CENTRAL SD...WITH
TROUGHING NUDGING DOWN INTO THE CENTRAL PLAINS. ANOTHER SURFACE LOW
IS SITUATED OVER THE OKLAHOMA PANHANDLE...WHICH IS THE RESULT OF A
VERY STRONG SHORTWAVE MOVING EASTWARD FROM THAT AREA TODAY...INTO
KANSAS...MISSOURI...SOUTHERN IOWA AREAS. THERE IS A LOT OF MODEL
CONSENSUS THAT THE HEAVIER RAIN WILL BE CONFINED TO THAT SHORT
WAVE AND SOUTH OF OUR AREA.
SO FROM HERE AND OUT...WE ARE MAINLY LEFTOVER WITH ISOLATED TO
SCATTERED INSTABILITY SHOWERS AND A FEW POSSIBLE THUNDERSTORMS...
ESPECIALLY THIS AFTERNOON. WENT DRY FOR OUR WESTERN ZONES THIS
MORNING AS THERE IS SIMPLY NO SIGN OF CONVECTIVE REDEVELOPMENT YET
IN CENTRAL NEB. THE 850MB STREAMLINES PRETTY MUCH TELL THE STORY
FOR NOW...IN THAT THEY ARE WRAPPING FROM A WESTERLY DIRECTION
UNDERNEATH THE AFOREMENTIONED LOW...COMING OUT OF WESTERN AND
CENTRAL NEBRASKA AND INTO OUR WESTERN ZONES. SO THE MOIST LOW
LEVEL FLOW IS CUTOFF IN OUR WEST. ALONG AND EAST OF I 29...THE LOW
LEVEL JET STILL EXISTS BUT IS WEAKER THEN YESTERDAY. ML CAPE IS
PRETTY ANEMIC THIS MORNING...BUT DOES INCREASE THIS AFTERNOON AS
ANY CLEARING WILL HELP TO HEAT THINGS OUT. IN ADDITION...SOME OF
THE HIGHER RESOLUTION MODELS ARE STRONGLY HINTING AT THE SURFACE
TROUGH MOVING EASTWARD INTO THE JAMES RIVER VALLEY THIS
AFTERNOON...WITH A DRY LINE PRESSING THROUGH OUR SOUTH CENTRAL SD
ZONES. THE TROUGH MAY PROVIDE A FOCUS FOR SCATTERED SHOWERS AND
STORMS ALONG AN AXIS FROM YANKTON TO SIOUX FALLS AND VICINITIES...
HELPED BY STRONGLY VEERING PROFILES JUST AHEAD OF THE DRY LINE.
ELSEWHERE AS THE AFTERNOON PROGRESSES...POPCORN TYPE INSTABILITY
SHOWERS AND THUNDERSTORMS SHOULD DOMINATE THIS AREA OF THE
SCATTERED VARIETY. SO VERY MUCH A NUISANCE SITUATION. HIGHS TODAY
STILL LOOK LIKE WIDESPREAD 70S...WHICH SHOULD BE ENOUGH TO PROVIDE
SOME AFTERNOON INSTABILITY.
FOR TONIGHT...ONCE THE HEATING SUBSIDES...SO WILL OUR CHANCE FOR
INSTABILITY RAINFALL. BUT LATE TONIGHT...THE UPPER LOW BEGINS TO
WRAP IN A CHANCE FOR SHOWERS INTO OUR NORTHWEST AREAS. MOISTURE
PROFILES IN THAT AREA ARE QUITE HIGH BY LATE TONIGHT...WITH DRY
SLOTTING TAKING OVER AFTER MIDNIGHT FOR THE REST OF OUR FORECAST
AREA.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 359 AM CDT THU MAY 30 2013
ON FRIDAY AND SATURDAY...OUR WEATHER WILL CONTINUE TO BE DOMINATED
BY THE UPPER LOW. IT WILL STILL BE CLOSED ON FRIDAY AS IT MOVES
SLOWLY EASTWARD. THEN IT WILL BECOME A TROUGH ON SATURDAY AS IT
MOVES INTO THE NORTHERN MISSISSIPPI VALLEY. PV IS VERY STRONG ON
THE NORTH AND WEST SIDES OF THE UPPER LOW...ALONG WITH STRONG
TROWALING CLEARLY EVIDENT AT THE MID LEVELS. ALL OF THIS IS
CAUSING A HIGH MOISTURE PROFILE WHICH MOVES SOUTHEASTWARD...SO
EXPECT LIGHT SHOWERS LIKELY TO MOVE IN THAT DIRECTION THROUGH
TIME AND EVENTUALLY ENCOMPASSING ALMOST THE ENTIRE WESTERN HALF OF
OUR FORECAST AREA. MODELS ARE CERTAINLY SHOWING QUITE A CONVEYOR
BELT OF PRECIPITATION...MOVING NORTHEASTWARD AHEAD OF THE LOW FROM
THE SOUTHERN PLAINS INTO THE GREAT LAKES...THEN LIGHT RAIN ARCHING
BACK THROUGH PARTS OF THE NORTHERN AND WESTERN PLAINS ALONG THE
TROWALING.
ANOTHER THING TO WATCH FOR FRIDAY AFTERNOON...IS THAT THE LEADING
EDGE OF THE COLD FRONT COULD SPARK SOME SCATTERED THUNDERSTORMS
ALONG AND SOUTH OF A SIOUX CITY TO WINDOM MN LINE. DO NOT THINK
THE COVERAGE OF STORMS WILL BE ALL THAT GREAT...AND ALMOST WENT
ISOLATED. BUT AGAIN SOMETHING TO WATCH FOR.
THIS COLD FRONT MOVES EASTWARD AND WILL GIVE OUR FORECAST AREA
SOME VERY CHILLY AIR TO CONTEND WITH ON SATURDAY. SATURDAY DOES
NOT LOOK LIKE A PLEASANT DAY...AS EVEN IF LIGHT SHOWERS DO NOT OCCUR
AT YOUR LOCATION...IT WILL BE CONSIDERABLY CLOUDY AND WINDY ALONG
WITH THE VERY CHILLY TEMPERATURES. RECORD LOW HIGHS ON JUNE 1 ARE
QUITE A BIT COLDER THAN WHAT WE HAVE FORECAST HOWEVER...SO THEY
SHOULD NOT BE IN JEOPARDY OF FALLING. SOME OF THE LIGHT SHOWERS BY
SATURDAY AFTERNOON WILL BE THE RESULT OF WHAT HEATING THERE IS.
THEREFORE BY SATURDAY NIGHT...ELIMINATED ALL POPS IN OUR EASTERN
ZONES. CONCERNING TEMPERATURES...COOLED OFF OUR WESTERN ZONES A
FAIR AMOUNT ON FRIDAY BEHIND THE COLD FRONT...NOTING THE CLOUDY
AND SHOWERY CONDITIONS.
THE SUNDAY THROUGH WEDNESDAY PERIOD WILL START DRY AND COOL
SUNDAY...BUT THE COOL WILL FEEL NICE WITH LIGHT TO MODERATE
NORTHERLY WINDS BEGINNING TO TURN EASTERLY AS SURFACE RIDGE PASSES
BY TO THE NORTH. WAS LOOKING FOR MONDAY TO BE DRY AND A LITTLE
WARMER...BUT IT LOOKS LIKE SOUTHEASTERLY THERMAL LIFT PATTERN WILL
DEVELOP SOON ENOUGH TO MENTION A SMALL CHANCE OF STORMS. THIS CHANCE
SHOULD BE SOMEWHAT BIGGER FOR THE REST OF THE PERIOD...MONDAY NIGHT
INTO WEDNESDAY...AS UPPER WAVE DIGS FROM SOUTHWEST CANADA INTO
THE DAKOTAS. WILL GO WITH GUIDANCE KEEPING TEMPERATURES FAIRLY
CLOSE TO SEASONAL FOR NOW...THIS SEEMS IN LINE WITH THE NEW ECMWF.
THE GFS WOULD SUGGEST COOLER BY WEDNESDAY. SINCE NO TREND IS SEEN
AS TO WHICH MODEL IS BETTER THAT FAR AHEAD...GUIDANCE AND
CONSISTENCY WIN FOR NOW. FOR THE MOMENT DO NOT EXPECT MOISTURE
INFLOW TO BE ENOUGH FOR SEVERE STORMS OR HEAVY RAIN...BUT MID AND
UPPER FLOW WILL BE MORE THAN AMPLE SO WILL HAVE TO BE OPEN TO
POSSIBLE CHANGE OF THINKING IN COMING DAYS.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 638 AM CDT THU MAY 30 2013
WIDESPREAD TO AREAS OF CEILINGS 1-3K FEET MOSTLY FROM A
BKX/FSD/SUX LINE AND EAST SHOULD IMPROVE FROM THE WEST 15Z-18Z.
OTHERWISE VFR WILL BE THE RULE OVER THE AREA WITH BRIEF CEILIGNS
2-3K FEET AND VISIBILITIES 3-5SM IN SGACTTERED TO ISOLATED
SHOWERS. ISOLATED THUNDERSTORMS POSSIBLE 18Z-31/02Z. WIDESPREAD
CEILINGS 2-3K FEET MAY DEVELOP WESTERN EDGE OF FORECAST AREA AFTER
31/06Z.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
UPDATE...
SHORT TERM...MJF
LONG TERM...MJF/WILLIAMS
AVIATION...
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
1237 AM CDT THU MAY 30 2013
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 404 PM CDT WED MAY 29 2013
COMPLEX SCENARIO TONIGHT BUT THE OVERALL MESSAGE LOOKS TO BE A LOW
END THREAT FOR SEVERE THUNDERSTORMS WITH A BETTER THREAT FOR
LOCALIZED HEAVY RAINFALL. CONVECTION CONTINUES TO SKIRT ALONG THE
WESTERN AND EASTERN EDGES OF THE CWA AS CONVECTION IN NEBRASKA
CONTINUES TO WEAKEN AS IT MOVES NORTH. SHEAR VALUES ARE MINIMALLY
SUPPORTIVE OF SEVERE CONVECTION WHILE CAPE VALUES ARE AROUND 1000 TO
1500 J/KG BUT OF THE VERY SKINNY VARIETY. THUS STARTING TO TREND
THINKING TOWARDS THE CONSISTENT HRRR WHICH FOR 5 RUNS IN A ROW HAS
PRODUCED A LARGE MCS WHICH CONGEALS FROM THE CONVECTION THAT IS
CURRENTLY DEVELOPING OVER THE WESTERN HIGH PLAINS. WILL RUN A BLEND
OF HPC/LOW RESOLUTION MODELS ALONG WITH THE HRRR AND RAP OUTPUT.
THE MAIN TAKE FROM THIS IS THAT THERE STILL APPEARS TO BE THE THREAT
FOR STORMS TO PRODUCE LOCALIZED RAINFALL AMOUNTS OF 3 TO 4 INCHES
WITH SLOW STORM MOVEMENT. WITH MOST LOCATIONS FLASH FLOOD GUIDANCE
RIGHT AROUND AN INCH AND A HALF OR A LITTLE MORE FLASH FLOODING WILL
BE A THREAT. THERE IS LIKELY TO BE A LULL IN CONVECTIVE ACTIVITY
LATE TONIGHT INTO TOMORROW MORNING THEN THE POTENTIAL FOR MORE
THUNDERSTORMS TOMORROW AFTERNOON...ESPECIALLY IN NORTHWEST IOWA AND
MAINLY SOUTHEAST PARTS OF SOUTHWEST MINNESOTA. CAPE VALUES JUST A
BIT MORE STOUT TOMORROW AND WIND SHEAR JUST A TOUCH BETTER SO AGAIN
NOT A WIDESPREAD THREAT BUT A THREAT NONETHELESS. LOWS TONIGHT
MAINLY 60 TO 65 WITH HIGHS ON THURSDAY IN THE MID 70S.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 404 PM CDT WED MAY 29 2013
LINGERING CONVECTION FROM DEVELOPMENT ON THURSDAY AFTERNOON WILL BE
SWINGING FAIRLY RAPIDLY THROUGH WITH STRONG PV LOBE LIFTING TO THE
NORTHEAST. MAIN UPPER WAVE WILL BE FAIRLY SLOW TO WOBBLE THROUGH THE
DAKOTAS THROUGH EARLY IN THE WEEKEND...BUT FIRST PART OF THIS PERIOD
WILL INTRODUCE A DRY SLOT AHEAD OF UPPER CIRCULATION THURSDAY NIGHT
INTO EARLY FRIDAY. AREA OF DIV Q BRUSHES UP AGAINST THE FAR
SOUTHEAST LATE AND WHILE BEST CHANCE FOR PRECIPITATION WILL CONTINUE
WELL SOUTHEAST...DID NUDGE A SMALL CHANCE FOR A LIGHT SHOWER INTO
THE FAR SOUTHEAST FOR A FEW HOURS AROUND DAYBREAK ON FRIDAY. IN
GENERAL...THE DRIER AIR WILL WORK THROUGH AREAS SOUTH OF THE UPPER
LOW AND WITH DIMINISHING WINDS ON THURSDAY NIGHT...WILL FIND LOWS
BACK IN THE UPPER 40S TO LOWER 50S FOR MOST.
SEVERAL DETERMINISTIC MODELS INDICATE A WEAK CONVERGENCE BOUNDARY
SLIDING THROUGH THE AREA ON LATER FRIDAY AFTERNOON AND FRIDAY
EVENING. AIRMASS DOES GET SOMEWHAT UNSTABLE...AND APPEARS TO BE
SETUP FOR DECENT MIXING WITH THE WEST TO SOUTHWEST FLOW COMPONENT AT
LOWER LEVELS THROUGH THE DAY. NET EFFECT WILL LIKELY BE AN ALMOST
UNCAPPED PROFILE WITH 400-700 J/KG INSTABILITY AND UNIMPRESSIVE
SHEAR. LIKELY WILL BE THE UNFAVORABLE AND WEAKLY SUBSIDENT LARGER
SCALE THAT WILL KEEP ACTION AT BAY UNTIL LATER INTO THE DIURNAL
CYCLE...WHEN PERHAPS SOME WEAK LOW LEVEL MOISTURE POOLING DUE TO
INDUCING SOMEWHAT STRONGER CONVERGENCE THAN MODEL INDICATED. STILL
WILL BE FAIRLY ISOLATED TO SCATTERED EVEN IT DOES DEVELOP WITH
MOISTURE LIMITATIONS.
AFTER VERY SHORT TERM...LOOKS LIKE LATER FRIDAY NIGHT INTO SATURDAY
WILL BE THE BEST CHANCE FOR PRECIPITATION ACROSS THE AREA...ALBEIT
MUCH LIGHTER THAN SHORTEST RANGE PRECIPITATION. UPPER TROUGH SWINGS
PAST WITH VERY COOL TEMPERATURES ALOFT. SHOULD BE PLENTY OF LOWER
LEVEL SHOWERS EVEN BEHIND PASSAGE OF UPPER WAVE ON SATURDAY
AFTERNOON WHICH CONTINUE TO ROTATE THROUGH NORTHEASTERN CWA.
BLUSTERY AND COOL DAY...WITH HIGHS UPPER 50S TO MID 60S. GFS
ENSEMBLE TEMPERATURE GUIDANCE STRONGLY SUGGESTS THAT COOLER IS
BETTER FOR SATURDAY. WINDS WILL DIMINISH...BUT A COOL NIGHT ON
SATURDAY NIGHT AS CLEARING PUSHES INTO THE WEST HALF.
FOR THE EXTENDED RANGE /SUNDAY THROUGH WEDNESDAY/ A FAIRLY QUIET
START WITH BRIEF RIDGING IN PLACE. STRETCHED OUT THE DIURNAL RANGE A
BIT FROM INITIALIZATION...AS EVEN WITH WET GROUND SHOULD BE ABLE TO
GET TOWARD FULL 850 HPA MIXING ON SUNDAY. DEVELOPMENT OF RETURN FLOW
FROM WEST TO EAST ON SUNDAY NIGHT INTO MONDAY MORNING. GFS/ECMWF
SHOWING SOME WEAK ELEVATED INSTABILITY/MOISTURE RETURN BY LATER
MONDAY...AND RELUCTANTLY INTRODUCED A LOW CHANCE FOR THUNDERSTORMS.
ANOTHER UPPER TROUGH WILL SETTLE INTO THE NORTHERN PLAINS TUESDAY
INTO WEDNESDAY...BUT THIS SOURCE WILL BE WITHIN LARGER SCALE
NORTHWEST FLOW AND IS SOMEWHAT MORE PROGRESSIVE THAN SHORT TERM
SYSTEM. SOME UNCERTAINTY IN TIMING AS BOUNDARY PUSHES THROUGH THE
AREA BUT HIGHEST CHANCES APPEAR CURRENTLY TO WORK THROUGH DURING THE
MONDAY NIGHT THROUGH TUESDAY NIGHT PERIOD. GENERALLY...TEMPERATURES
WILL BE WORKING SLOWLY UPWARD THROUGH TUESDAY...THEN SLIPPING BACK A
TOUCH WITH BOUNDARY PASSAGE AND PRECIPITATION LATER TUESDAY INTO
WEDNESDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1237 AM CDT THU MAY 30 2013
WITH LOWER LEVELS HAVING DRIED OUT IN INCREASING SOUTHERLY
FLOW...VFR IS NOW EXPECTED TO BE GENERAL EXCEPT FOR A PERIOD OF
CEILINGS 1-3K FEET SOUTH AND EAST OF FSD 09Z-15Z. OTHERWISE A FEW
AREAS OF THESE MVFR CONDITIONS WILL BE POSSIBLE IN SCATTERED
SHOWERS AND ISOLATED THUNDERSTORMS THROUGH 15Z. 15Z-31/01Z VFR
EXCEPT LOCAL AND BRIEF CEILINGS 2-3K FEET AND VISIBILITIES 3-5SM
IN ISOLATED TSRA EAST AND SOUTH OF FSD. AFTER 01Z VFR OVER AREA.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...FLASH FLOOD WATCH UNTIL 7 AM CDT THIS MORNING FOR IAZ002-003-
012>014-020>022-031-032.
NE...FLASH FLOOD WATCH UNTIL 7 AM CDT THIS MORNING FOR NEZ014.
&&
$$
SHORT TERM...08
LONG TERM...CHAPMAN
AVIATION...
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
1001 PM CDT FRI MAY 31 2013
.UPDATE...FORECAST SEEMS TO BE IN GOOD SHAPE. STILL SOME
UNCERTAINTY HOW MUCH WILL BE LEFT OF THE CONVECTIVE SYSTEM OVER
MO WHEN IT APPROACHES MID TN TOWARD DAYBREAK. CURRENTLY WE HAVE
20 POPS NORTHWEST AND THIS SEEMS REASONABLE...AND IS SUPPORTED BY
THE LATEST HRRR AND NAM12. WE WILL CONTINUE TO MONITOR THE
PROGRESS AND NEW SHORT RANGE MODELS FOR POSSIBLE UPDATES. OTHER
ELEMENTS LOOK FINE WITH PARTLY CLOUDY SKIES AND LOWS IN THE LOWER
70S FOR MOST LOCATIONS.
13
&&
.PREV DISCUSSION... /ISSUED 634 PM CDT FRI MAY 31 2013/
UPDATE...FOR 00Z AVIATION.
AVIATION...00Z TAF DISCUSSION.
ONE OR TWO SHOWERS ACROSS NORTH MIDDLE TENNESSEE AT ISSUANCE THIS
EVENING...BUT THESE WILL MOVE OFF INTO KY OVER THE NEXT HOUR...AND
THE REMAINDER OF THE AFTERNOON CUMULUS WILL DISSIPATE LEAVING A
FEW HIGH CLOUDS AROUND FOR THE FIRST PART OF THE NIGHT. THE FOCUS
WILL BE THE LARGE CLUSTER OF SHOWERS AND THUNDERSTORMS...OR
MCS...THAT IS BACK OVER CENTRAL MISSOURI. SOME OF THE HIGH RES
MODELS ARE SUGGESTING THAT A SOUTHEASTERLY TURN OF THIS MCS WILL
BRING THE POTENTIAL FOR SOME SHOWERS INTO OUR NORTHWEST...AND THAT
MEANS KCKV...BY DAYBREAK. WILL WAIT UNTIL THE 06Z ISSUANCE TO SEE
FOR SURE THAT IT WILL MAKE THE HARD SOUTHERLY TURN BEFORE
INCLUDING IN PREVAILING. FOR NOW...WILL KEEP VFR CONDITIONS FOR
ALL TERMINALS...AND BRING BACK THE BREEZE AND VCTS FOR EVERYONE BY
LATE SATURDAY MORNING AS A FRONTAL SYSTEM STARTS TO WORK ITS WAY
TOWARDS THE STATE.
27
PREV DISCUSSION... /ISSUED 331 PM CDT FRI MAY 31 2013/
DISCUSSION...
MCV CONTINUES MOVING NORTHEAST ACROSS KY PER LATEST RADAR
IMAGERY AND HAS TAKEN BULK OF SHOWERS/STORMS WITH IT...WITH JUST A
FEW SHOWERS ONGOING ACROSS OUR CWA. EXPECT DIURNAL SHOWERS WILL
DISSIPATE QUICKLY BY SUNSET WITH DRY CONDITIONS TONIGHT. WILL KEEP
AN EYE TO OUR NORTHWEST AS MODELS ALL DEVELOP ANOTHER LARGE MCS
ACROSS MO/IL THAT MAKES A RUN FOR OUR NORTHWEST CWA TOWARDS/AFTER
12Z SATURDAY MORNING. HOWEVER...APPEARS THIS MCS WILL WEAKEN
SUBSTANTIALLY PRIOR TO REACHING THE MID STATE AND WILL KEEP POPS
LOWER THAN LATEST MOS FOR OUR NORTHWEST ZONES.
ADDITIONAL SCATTERED SHOWERS AND THUNDERSTORMS WILL DEVELOP
SATURDAY AFTERNOON ALONG REMNANT OUTFLOW BOUNDARIES FROM MCS AS
WELL AS SYNOPTIC COLD FRONT ACROSS MO/IL...WITH ACTIVITY
CONGEALING INTO ANOTHER MCS THAT MOVES ACROSS THE CWA SATURDAY
NIGHT. 12Z GFS/ECMWF APPEAR A BIT FASTER THAN PREVIOUS RUNS WITH
BULK OF ACTIVITY IN THE 00Z-06Z TIMEFRAME. FORECAST SOUNDINGS
CONTINUE TO DEPICT MODERATE INSTABILITY/SHEAR PARAMETERS WITH LI
VALUES AROUND -6 AND BULK SHEAR UP TO 40 KTS IN A HIGHLY MOIST
ENVIRONMENT WITH PWATS OVER 1.75 INCHES...SUGGESTING SOME STRONG
TO SEVERE THUNDERSTORMS WILL BE POSSIBLE WITH DAMAGING WINDS AND
LOCALLY HEAVY RAINFALL THE MAIN THREATS. LARGE HAIL APPEARS TO BE
A LOWER THREAT DUE TO WARM MID LEVEL TEMPERATURES AROUND -8C AT
500MB AND HIGH FREEZING LEVELS OF 14-15K FT. SPC CONTINUES TO
HIGHLIGHT THE ENTIRE CWA IN A SLIGHT RISK FOR SATURDAY
AFTERNOON/NIGHT ALTHOUGH THE HIGHEST SEVERE POTENTIAL WILL BE
ACROSS THE NORTHWEST HALF OF THE MID STATE.
COLD FRONT PROGRESSING THROUGH THE FORECAST AREA WILL SPARK
ADDITIONAL SHOWERS/STORMS SUNDAY...BUT DRIER AIR FILTERING IN
BEHIND THE FRONT WILL BRING AN END TO ALL PRECIP BY SUNDAY NIGHT.
MUCH COOLER TEMPS ANTICIPATED FOR EARLY NEXT WEEK WITH HIGHS IN
THE 70S TO LOWER 80S AND LOWS IN THE 50S TO LOWER 60S. A WARMING
TREND WILL BEGIN BY MID WEEK AS A TROUGH DEPARTS THE EAST COAST
AND HEIGHTS ALOFT RISE...WITH A SLIGHT CHANCE FOR SHOWERS AND
STORMS EACH DAY THROUGH THE END OF THE WEEK.
&&
.OHX WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS SAN ANGELO TX
716 PM CDT FRI MAY 31 2013
.DISCUSSION...
SEE 00Z AVIATION DISCUSSION BELOW.
&&
.AVIATION...
SKIES WILL REMAIN CLEAR ACROSS THE AREA THROUGH THE EVENING HOURS.
MOISTURE WILL AGAIN MOVE NORTH INTO THE AREA OVERNIGHT
TONIGHT...BRINGING MVFR CIGS TO OUR SOUTHERN AND EASTERN TAF
SITES. THESE CIGS ARE EXPECTED TO MIX OUT BEFORE 18Z. A COLD FRONT
WILL MOVE INTO THE AREA TOMORROW AS WELL...LIKELY AFFECTING KABI
WITH NORTHERLY WINDS BY 15Z...KSJT BY 18Z...AND SOUTHERN SITES
AFTER 18Z. HAVE GONE AHEAD AND INSERTED VCTS TOMORROW AFTERNOON FOR
SOUTHERN AND EASTERN SITES WHERE THUNDERSTORMS ARE MORE LIKELY. 20
&&
.PREV DISCUSSION... /ISSUED 344 PM CDT FRI MAY 31 2013/
TONIGHT...
INSTABILITY WAS HIGH ACROSS WEST CENTRAL TEXAS WITH RAP ML CAPES
EXCEEDING 5000 J/KG. A STRONG CAP HOWEVER WAS PREVENTING STORM
DEVELOPMENT. I DID ADD A SLIGHT CHANCE OF THUNDERSTORMS IN HASKELL
AND THROCKMORTON COUNTIES THIS EVENING...WHERE A CUMULUS FIELD WAS
BEGINNING TO DEVELOP IN AN AREA OF WEAK SURFACE CONVERGENCE EAST
OF THE DRYLINE. AGAIN...LIKE YESTERDAY...IF STORMS DO
DEVELOP...THEY COULD RAPIDLY BECOME SEVERE WITH LARGE HAIL AND
DAMAGING WINDS. A TORNADO IS ALSO NOT OUT OF QUESTION WITH VERY
STRONG INSTABILITY PRESENT.
OTHERWISE A WARM NIGHT WITH LOW LEVEL MOISTURE CONTINUING TO FLOW
FROM THE GULF MEXICO. STRATUS RETURNS AFTER MIDNIGHT...FROM THE
HILL COUNTRY. 850 MB LOW LEVEL JET AGAIN PICKS UP TO 45-50 KTS
TOWARD MIDNIGHT. PERSISTENCE FORECAST TONIGHT WITH LOWS IN THE
LOWER TO MID 70S.
SATURDAY AND SUNDAY...
AS THE FRONT PUSHES SOUTH ACROSS THE AREA SATURDAY
MORNING...THINGS SHOULD STAY RELATIVELY QUITE. WITH DAYTIME
HEATING AND DEWPOINTS AROUND 70 DEGREES...SURFACE BASED CAPE WILL
INCREASE TO AROUND 3500 J/KG BY MID AFTERNOON. WITH THE FORCING
FROM THE FRONT...REALIZING THIS INSTABILITY SHOULD NOT BE A
PROBLEM. THE CIN VALUES ARE REASONABLE...HIGH ENOUGH TO ALLOW THE
INSTABILITY TO BUILD...BUT NOT TOO MUCH TO KEEP ANY OF IT FROM
BEING RELEASED. SHEAR WILL NOT BE SPECTACULAR...BUT WITH 30 KTS
THERE WILL BE ENOUGH FOR SUPPORT VIGOROUS UPDRAFTS. THE MAIN
THREAT WILL BE VERY LARGE HAIL. LOW LEVEL SHEAR IS
LACKLUSTER...ONLY MAYBE 10 KTS...SO THE TORNADO THREAT SHOULD BE
LIMITED...THOUGH IT CANNOT BE RULED OUT. IF A STORM CAN STAY ALONG
THE BOUNDARY FOR LONG ENOUGH...IT WILL BE POSSIBLE FOR A
CIRCULATION TO DEVELOP. THE MAIN AREA OF CONCERN IS THE
SOUTHEASTERN PART OF THE AREA...SOUTH OF A LINE FROM
BROWNWOOD...TO SAN ANGELO...TO OZONA. OTHERWISE...TEMPERATURES
WILL COOL OFF A LITTLE FROM FRIDAY BEHIND THE FRONT. HIGHS WILL
GENERALLY BE IN THE UPPER 80S TO LOWER 90S FOR SATURDAY AND
SUNDAY. LOWS WILL IN THE 60S TO LOWER 70S. RAIN CHANCES SHOULD
MOVE OUT BY EARLY AFTERNOON ON
SUNDAY NIGHT THROUGH FRIDAY...
RIDGE OF HIGH PRESSURE IN THE MID AND UPPER LEVELS ACROSS THE
ATMOSPHERE WILL BECOME ESTABLISHED FOR AT LEAST THE FIRST HALF OF
NEXT WEEK. TEMPERATURES WILL LIKELY SOAR WITH THE RIDGE...WITH THE
LOCATION OF THE THERMAL RIDGE SUGGESTING THAT READINGS AT LEAST
NEAR THE 100 DEGREE MARK ARE POSSIBLE FOR THE WESTERN HALF OF THE
AREA.
THE GFS WEAKENS THE RIDGE FOR THE LAST HALF OF THE WEEK...AND
TRIES ANOTHER FRONT AND CONVECTION INTO THE ARE FOR THURSDAY OR
FRIDAY. ECMWF SHOWS A LITTLE MORE PERSISTENT RIDGE...AND DELAYS
ANY CONVECTION TIL FRIDAY. AT THIS POINT...THINK KEEPING THE
FORECAST DRY FOR NOW IS PROBABLY THE BEST OPTION...AND LET THE
UNCERTAINTIES SETTLE A LITTLE.
&&
.PRELIMINARY POINT TEMPS/POPS...
ABILENE 73 90 65 89 66 / 10 20 30 10 10
SAN ANGELO 74 93 71 91 69 / 5 30 30 20 10
JUNCTION 73 94 70 92 68 / 5 30 40 20 10
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
340 PM CDT THU MAY 30 2013
.TONIGHT AND FRIDAY...
A CONDITIONAL CHANCE OF THUNDERSTORMS THIS AFTERNOON AND
EVENING... BASED ON WHERE THE CAP WILL HOLD. WHILE THE CAP WILL
LIKELY HOLD...IF IT DOES BREAK...WITH RAP SB CAPES OF 4000
J/KG...STORMS COULD RAPIDLY BECOME SEVERE. 0-6 KM SHEARS WERE 40
KTS IN THE BIG COUNTRY WITH HIGHER VALUES FARTHER NORTH. A TORNADO
WATCH IS IN EFFECT FOR NORTHERN SECTIONS OF THE THE BIG COUNTRY
THROUGH 10 PM CDT...WHERE AN ENHANCED CUMULUS FIELD WAS INDICATED.
DRYLINE OTHERWISE EXTENDED ALONG THE WESTERN EDGE OF THE SAN ANGELO
CWA THIS AFTERNOON...FROM IRAAN TO SWEETWATER TO NEAR ASPERMONT. BEST CHANCE
OF A STORM WILL BE IN LOW LEVEL CONVERGENCE ALONG THE FRONT...AND
MAINLY NORTH OF THE I-20 CORRIDOR. GENERAL MOVEMENT OF STORMS WILL
BE EAST ...WITH SEVERE OR STORM STORMS PROPAGATING SOUTHEAST.
OTHERWISE ANTHER WARM NIGHT WITH CONTINUED MOISTURE TRANSPORT FROM THE
GULF. OVERNIGHT LOWS WILL BE IN THE LOWER 70S. A DRYLINE WILL BE
MOVING A LITTLE FARTHER EAST FRIDAY AFTERNOON....ALONG A SONORA...SAN
ANGELO... ABILENE...HASKELL LINE. WITH GFS 850 MB TEMPERATURES
INCREASING TO 30 C WEST OF THE DRYLINE...SHOULD SEE SURFACE
TEMPERATURES AT OR SLIGHTLY ABOVE 100 DEGREES F WEST OF THE
DRYLINE... WITH 90S TO THE EAST.
FIRE WEATHER CONDITIONS WILL BE ELEVATED WEST THE DRYLINE THIS
AFTERNOON. WINDS HOWEVER WILL WEAKEN SLIGHTLY THIS EVENING...THEN
BECOME MORE GUSTY BY MIDNIGHT...AS 45-50 KT 850 MB LLJ DEVELOPS.
GUSTY MORNING SOUTH TO SOUTHWEST WINDS WEAKEN ENOUGH BY FRIDAY
AFTERNOON TO KEEP CONDITIONS FROM BECOMING CRITICAL FOR FIRE WEATHER.
.SATURDAY THROUGH SUNDAY...
NEXT BEST CHANCE OF RAIN FOR WEST CENTRAL TEXAS WILL COME FOR THE
WEEKEND...AS A COLD FRONT MOVES INTO THE AREA. MODELS HAVE BEEN
FAIRLY CONSISTENT WITH THE TIMING OF THE FRONT...MOVING TO NEAR
THE NORTHWEST BORDER OF THE AREA BY SATURDAY MORNING...AND THEN
SLOWLY SLIDING IT DEEPER INTO WEST CENTRAL TEXAS DURING THE DAY.
AT LEAST SCATTERED SHOWERS AND STORMS SHOULD BREAK OUT ALONG AND
NORTH OF THE BOUNDARY SATURDAY AFTERNOON...AND CONTINUE THROUGH
THE OVERNIGHT HOURS. HAVE INCREASED RAIN CHANCES ACROSS MUCH OF
THE AREA JUST A LITTLE.
WHATS LEFT OF THE BOUNDARY SHOULD BE DISSIPATING ACROSS THE AREA
DURING THE DAY ON SUNDAY. WITH NOT MUCH OF THE BOUNDARY
LEFT...DONT EXPECT STORMS TO BE QUITE AS WIDESPREAD. WILL CONTINUE
THE SLIGHT CHANCE POPS OVER MUCH OF THE AREA.
.SUNDAY THROUGH THURSDAY...
DRY CONDITIONS FOR THE PERIOD FOR NOW. MID AND UPPER LEVEL RIDGE
BUILDS INTO THE SOUTHERN ROCKIES...PLACING WEST CENTRAL TEXAS IN
WEAK NORTHWEST FLOW ALOFT. APPEARS WE MAY BE A LITTLE TOO CLOSE TO
THE RIDGE CENTER TO TAKE ADVANTAGE OF THE NORMALLY WETTER SUMMER
NORTHWEST GLOW PATTERN INTO WEDNESDAY. MODELS HAVE SOME
DIFFERENCES BY THE TIME WE GET INTO THURSDAY...WITH THE GFS
SUPPRESSING THE RIDGE ENOUGH TO ALLOW ANOTHER FRONT INTO THE
AREA...WHILE THE ECMWF TRIES TO CLOSE OFF AN UPPER LOW OVER
SOUTHERN CALIFORNIA. AT THIS POINT...WILL JUST LEAVE DRY FOR NOW.
&&
.PRELIMINARY POINT TEMPS/POPS...
ABILENE 72 99 74 92 65 / 10 10 10 20 30
SAN ANGELO 73 99 74 96 67 / 10 10 5 20 30
JUNCTION 72 94 73 94 71 / 10 5 5 10 30
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
04/07/07
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
211 AM CDT SAT JUN 1 2013
.DISCUSSION...
336 PM CDT
THOUGHTS FROM THE EARLIER MESO DISCUSSION ARE STILL VALID AND HAVE
BEEN BOLSTERED BY THE SPREAD OF SHOWERS WITH ISOLATED TSRA INTO THE
FCST AREA THIS AFTERNOON WITH LITTLE ADDITIONAL DEVELOPMENT DIRECTLY
WEST OVER IOWA SO FAR. 0-6 KM BULK SHEAR CONTINUES TO BE MARGINAL
OVER MOST OF THE LOCAL REGION BUT IS BUILDING TOWARD 40 KTS IN THE
AREA OF APPROACHING CONVECTION TO OUR SOUTHWEST UNDER THE LEADING
EDGE OF AN UPPER LEVEL JET. A FEW STORMS COULD BECOME ORGANIZED IN
SOUTHERN PORTIONS OF THE CWA...THOUGH THE SEVERE RISK OVERALL
APPEARS TO BE MARGINAL. TRENDS FOR THIS EVENING AND OVERNIGHT
ALSO WOULD CONTINUE TO FAVOR SOUTHERN PORTIONS OF THE CWA FOR THE
HEAVIEST RAINFALL AMOUNTS AND THE CORRESPONDING FLOOD RISK...AND
THIS ALSO IS WHERE THE MOST RAIN HAS FALLEN OVER THE PAST WEEK. FOR
THESE REASONS...AFTER COORDINATION WITH NEIGHBORS...WILL PLAN TO
DROP THE FLOOD WATCH FOR NORTHERN PORTIONS OF THE FORECAST AREA.
ALL OF THIS ACTIVITY IS BEING DRIVEN BY RICH BOUNDARY LAYER GULF
MOISTURE WRAPPING AROUND THE WESTERN SIDE OF A BERMUDA HIGH...AND
AHEAD OF AN APPROACHING FRONTAL ZONE TIED TO LOW PRESSURE OVER THE
DAKOTAS. THIS FRONTAL ZONE PUSHES THROUGH THE AREA SATURDAY NIGHT
AND USHERS IN COOLER AND DRIER AIR FOR THE FIRST HALF OF NEXT WEEK.
UNSETTLED WEATHER WILL PERSIST UNTIL THAT TIME WITH THE FOCUS
GRADUALLY SHIFTING EASTWARD. SHOWER AND THUNDERSTORM FORECAST
TRENDS FOR THIS EVENING AND OVERNIGHT ARE BASED ON CURRENT ACTIVITY
AND THE IDEA OF INCREASING DEVELOPMENT SUPPORTED BY LOW LEVEL
MOISTURE CONVERGENCE BEING DEPICTED IN THE RAP MODEL. IF THESE RAP
FIELDS CONTINUE TO BE VALID TOWARD MORNING...THE NORTHWEST HALF OF
THE AREA WOULD APPEAR TO DRY OUT BY MIDNIGHT AND REMAIN SO INTO THE
MORNING HOURS. THIS TREND ALSO IS SUPPORTED BY THE LATEST
NAM/ECMWF/GFS QPF FIELDS. CHANCES THEN INCREASE AGAIN DURING THE
DAY TOMORROW AHEAD OF THE APPROACHING UPPER LEVEL VORT MAX AND THE
SURFACE FRONTAL ZONE.
AFTER A COOLER AND DRIER END TO THE WEEKEND AND START TO THE WORK
WEEK...THE NEXT UPPER TROUGH AND SFC LOW BEGIN TO APPROACH THE
AREA TOWARD THE MIDDLE OF NEXT WEEK ALONG THE SIMILAR DAKOTAS TRACK
THAT WE HAVE SEEN WITH THE CURRENT SYSTEM. SFC WINDS TURNING
SOUTHEAST BY WEDNESDAY AND SOUTH BY THURSDAY WOULD ALLOW WARM MOIST
GULF AIR TO START WORKING BACK INTO THE AREA FOR LATE NEXT
WEEK...BUT AT THIS RANGE WILL ONLY PLAN TO CARRY CHANCE POPS.
LENNING
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 06Z...
* NEARBY PATCHY MVFR CIGS PRIOR TO DAYBREAK.
* SSW TO SW WINDS INCREASING DURING THIS AFTERNOON.
* CHANCE OF TSRA THIS AFTERNOON.
//DISCUSSION...UPDATED 06Z...
LOW PRESSURE OVER MN EARLY THIS MORNING WILL DEVELOP EASTWARD INTO
THE CENTRAL GREAT LAKES BY THIS EVENING. CONTINUED SOUTHERLY FLOW
WILL TURN MORE SOUTHWESTERLY THIS AFTERNOON. LINGERING JUICY LOW-
LEVEL AIR WILL PRESENT THE POSSIBILITY OF PATCHY MVFR CIGS AND
POSSIBLY EVEN VISIBILITIES EARLY THIS MORNING. WHILE SOME EARLY
MORNING ISOLATED SHRA/TSRA MAY SPARK IN NW IL/SW WI...AND
POSSIBLY NEAR RFD...MOST OF THE REGION SHOULD NOW BE DRY FOR THE
MORNING. THIS AFTERNOON IS ANTICIPATED TO SEE SCATTERED SHRA/TSRA
DEVELOPMENT IN THE AREA...WITH MORE FOCUSED DEVELOPMENT ACROSS
CENTRAL IL INTO IN BASED ON THE TRAJECTORIES OF UPPER LEVEL
DISTURBANCES.
//ORD AND MDW CONFIDENCE...UPDATED 06Z...
* MEDIUM CONFIDENCE THAT MVFR CIGS WILL REMAIN AWAY FROM THE
AIRPORTS THROUGH THIS MORNING.
* MEDIUM CONFIDENCE IN WIND SPEEDS...HIGH CONFIDENCE IN DIRECTION
THIS AFTERNOON.
* LOW CONFIDENCE IN TSRA CHANCES SAT AFTERNOON.
//OUTLOOK FOR ORD/MDW FOR 12Z SUNDAY-12Z FRIDAY...UPDATED 00Z...
SUNDAY THROUGH TUESDAY...VFR.
WEDNESDAY AND THURSDAY...CHANCE OF TSRA.
MTF/IZZI
&&
.MARINE...
210 AM CDT
LOW PRESSURE WILL MAINTAIN ITS INTENSITY TODAY AS IT SHIFTS ACROSS
WI AND TO THE CENTRAL GREAT LAKES BY THIS EVE. INITIALLY IN THE
SOUTHERLY FLOW AHEAD OF THE LAKE...MOIST AIR OVER THE COOLER LAKE
HAS LED TO FOG. WHILE IT CANNOT BE DETERMINED HOW WIDESPREAD THIS
IS...THERE HAVE BEEN MULTIPLE SHIPS OBS SINCE FRIDAY NIGHT TO HAVE
REPORTED DENSE FOG...ALONG WITH A COUPLE NEARBY SHORE LOCATIONS IN
MI. A COLD FRONT EXTENDING FROM THE LOW WILL MOVE ACROSS THE LAKE
LATE TONIGHT TURNING THE WINDS NORTHWESTERLY AND PROVIDING AN
INCREASE IN SPEED WITH COLD AIR ADVECTION INTO SUNDAY. HIGH PRESSURE
WILL THEN BRING TRANQUIL CONDITIONS ACROSS THE LAKE MON AND TUE
BEFORE A WEAK TROUGH PASSAGE...WHICH WILL THEN AGAIN BE FOLLOWED BY
RIDGING.
MTF
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...FLASH FLOOD WATCH...ILZ021-ILZ022-ILZ023-ILZ032-ILZ033-ILZ039
UNTIL 7 PM SATURDAY.
IN...FLASH FLOOD WATCH...INZ001-INZ002-INZ010-INZ011-INZ019 UNTIL 7
PM SATURDAY.
LM...DENSE FOG ADVISORY...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ868-LMZ870-
LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 9 PM SATURDAY.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
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WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1250 AM CDT SAT JUN 1 2013
.DISCUSSION...
336 PM CDT
THOUGHTS FROM THE EARLIER MESO DISCUSSION ARE STILL VALID AND HAVE
BEEN BOLSTERED BY THE SPREAD OF SHOWERS WITH ISOLATED TSRA INTO THE
FCST AREA THIS AFTERNOON WITH LITTLE ADDITIONAL DEVELOPMENT DIRECTLY
WEST OVER IOWA SO FAR. 0-6 KM BULK SHEAR CONTINUES TO BE MARGINAL
OVER MOST OF THE LOCAL REGION BUT IS BUILDING TOWARD 40 KTS IN THE
AREA OF APPROACHING CONVECTION TO OUR SOUTHWEST UNDER THE LEADING
EDGE OF AN UPPER LEVEL JET. A FEW STORMS COULD BECOME ORGANIZED IN
SOUTHERN PORTIONS OF THE CWA...THOUGH THE SEVERE RISK OVERALL
APPEARS TO BE MARGINAL. TRENDS FOR THIS EVENING AND OVERNIGHT
ALSO WOULD CONTINUE TO FAVOR SOUTHERN PORTIONS OF THE CWA FOR THE
HEAVIEST RAINFALL AMOUNTS AND THE CORRESPONDING FLOOD RISK...AND
THIS ALSO IS WHERE THE MOST RAIN HAS FALLEN OVER THE PAST WEEK. FOR
THESE REASONS...AFTER COORDINATION WITH NEIGHBORS...WILL PLAN TO
DROP THE FLOOD WATCH FOR NORTHERN PORTIONS OF THE FORECAST AREA.
ALL OF THIS ACTIVITY IS BEING DRIVEN BY RICH BOUNDARY LAYER GULF
MOISTURE WRAPPING AROUND THE WESTERN SIDE OF A BERMUDA HIGH...AND
AHEAD OF AN APPROACHING FRONTAL ZONE TIED TO LOW PRESSURE OVER THE
DAKOTAS. THIS FRONTAL ZONE PUSHES THROUGH THE AREA SATURDAY NIGHT
AND USHERS IN COOLER AND DRIER AIR FOR THE FIRST HALF OF NEXT WEEK.
UNSETTLED WEATHER WILL PERSIST UNTIL THAT TIME WITH THE FOCUS
GRADUALLY SHIFTING EASTWARD. SHOWER AND THUNDERSTORM FORECAST
TRENDS FOR THIS EVENING AND OVERNIGHT ARE BASED ON CURRENT ACTIVITY
AND THE IDEA OF INCREASING DEVELOPMENT SUPPORTED BY LOW LEVEL
MOISTURE CONVERGENCE BEING DEPICTED IN THE RAP MODEL. IF THESE RAP
FIELDS CONTINUE TO BE VALID TOWARD MORNING...THE NORTHWEST HALF OF
THE AREA WOULD APPEAR TO DRY OUT BY MIDNIGHT AND REMAIN SO INTO THE
MORNING HOURS. THIS TREND ALSO IS SUPPORTED BY THE LATEST
NAM/ECMWF/GFS QPF FIELDS. CHANCES THEN INCREASE AGAIN DURING THE
DAY TOMORROW AHEAD OF THE APPROACHING UPPER LEVEL VORT MAX AND THE
SURFACE FRONTAL ZONE.
AFTER A COOLER AND DRIER END TO THE WEEKEND AND START TO THE WORK
WEEK...THE NEXT UPPER TROUGH AND SFC LOW BEGIN TO APPROACH THE
AREA TOWARD THE MIDDLE OF NEXT WEEK ALONG THE SIMILAR DAKOTAS TRACK
THAT WE HAVE SEEN WITH THE CURRENT SYSTEM. SFC WINDS TURNING
SOUTHEAST BY WEDNESDAY AND SOUTH BY THURSDAY WOULD ALLOW WARM MOIST
GULF AIR TO START WORKING BACK INTO THE AREA FOR LATE NEXT
WEEK...BUT AT THIS RANGE WILL ONLY PLAN TO CARRY CHANCE POPS.
LENNING
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 06Z...
* NEARBY PATCHY MVFR CIGS PRIOR TO DAYBREAK.
* SSW TO SW WINDS INCREASING DURING THIS AFTERNOON.
* CHANCE OF TSRA THIS AFTERNOON.
//DISCUSSION...UPDATED 06Z...
LOW PRESSURE OVER MN EARLY THIS MORNING WILL DEVELOP EASTWARD INTO
THE CENTRAL GREAT LAKES BY THIS EVENING. CONTINUED SOUTHERLY FLOW
WILL TURN MORE SOUTHWESTERLY THIS AFTERNOON. LINGERING JUICY LOW-
LEVEL AIR WILL PRESENT THE POSSIBILITY OF PATCHY MVFR CIGS AND
POSSIBLY EVEN VISIBILITIES EARLY THIS MORNING. WHILE SOME EARLY
MORNING ISOLATED SHRA/TSRA MAY SPARK IN NW IL/SW WI...AND
POSSIBLY NEAR RFD...MOST OF THE REGION SHOULD NOW BE DRY FOR THE
MORNING. THIS AFTERNOON IS ANTICIPATED TO SEE SCATTERED SHRA/TSRA
DEVELOPMENT IN THE AREA...WITH MORE FOCUSED DEVELOPMENT ACROSS
CENTRAL IL INTO IN BASED ON THE TRAJECTORIES OF UPPER LEVEL
DISTURBANCES.
//ORD AND MDW CONFIDENCE...UPDATED 06Z...
* MEDIUM CONFIDENCE THAT MVFR CIGS WILL REMAIN AWAY FROM THE
AIRPORTS THROUGH THIS MORNING.
* MEDIUM CONFIDENCE IN WIND SPEEDS...HIGH CONFIDENCE IN DIRECTION
THIS AFTERNOON.
* LOW CONFIDENCE IN TSRA CHANCES SAT AFTERNOON.
//OUTLOOK FOR ORD/MDW FOR 12Z SUNDAY-12Z FRIDAY...UPDATED 00Z...
SUNDAY THROUGH TUESDAY...VFR.
WEDNESDAY AND THURSDAY...CHANCE OF TSRA.
MTF/IZZI
&&
.MARINE...
222 PM CDT
AN AREA OF LOW PRESSURE THAT HAS PERSISTED OVER THE NORTHERN PLAINS
WILL FINALLY BEGIN TO MOVE EAST TONIGHT...PASSING OVER NORTHERN LAKE
MICHIGAN LATE SATURDAY EVENING WITH A TRAILING COLD FRONT TURNING
MODERATE SOUTHERLY WINDS OF 15 TO 25 KT TO NORTHWESTERLY. MOIST FLOW
AHEAD OF THE FRONT HAS ALREADY LED TO DENSE FOG OVER MUCH OF THE
LAKE WHICH IS EXPECTED TO PERSIST UNTIL THE COLD FRONT PASSES
SATURDAY NIGHT. WINDS SHOULD THEN DIMINISH THROUGH THE DAY SUNDAY AS
HIGH PRESSURE BUILDS IN FROM THE WEST...BECOMING CENTERED OVER LAKE
MICHIGAN ON MONDAY. LOW PRESSURE WILL DEVELOP OVER THE CENTRAL
PLAINS MONDAY...THEN LIFT NORTHEAST TO LAKE MICHIGAN LATE THURSDAY
INTO EARLY FRIDAY.
BMD
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...FLASH FLOOD WATCH...ILZ021-ILZ022-ILZ023-ILZ032-ILZ033-ILZ039
UNTIL 7 PM SATURDAY.
IN...FLASH FLOOD WATCH...INZ001-INZ002-INZ010-INZ011-INZ019 UNTIL 7
PM SATURDAY.
LM...DENSE FOG ADVISORY...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ868-LMZ870-
LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 9 PM SATURDAY.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
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WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1114 PM MDT FRI MAY 31 2013
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 152 PM MDT FRI MAY 31 2013
EARLY AFTERNOON WV IMAGERY AND RAP H5 ANALYSIS SHOW LARGE SCALE
TROUGH STILL IN PLACE ACROSS NORTHERN PLAINS WITH CLOSED CENTER
OVER THE EASTERN DAKOTAS. A SERIES OF WEAK VORTICITY MAXIMA ARE
ROTATING AROUND THE WESTERN EXTENT OF THE UPPER LOW PRODUCING
MID-HIGH CLOUDS ACROSS THE PLAINS. OVER THE SOUTHERN PART OF OUR CWA
STEEP LAPSE RATES ALONG A BAROCLINIC ZONE HAS LED TO DEVELOPMENT OF
HIGH BASED SHOWERS/VIRGA. WITH BASES GENERALLY AROUND 12KFT AND A
DEEP DRY LAYER BELOW THIS...IT IS UNLIKELY MUCH MORE THAN A FEW
SPRINKLES WILL REACH THE SURFACE WITH THIS ACTIVITY.
RED FLAG CONDITIONS AND GUSTY WINDS SHOULD CONTINUE THROUGH THE EARLY
EVENING PERIOD ACROSS NW HALF OF THE CWA. LIMITING FACTOR FOR RFW
CONTINUES TO BE FUELS...AND WITHOUT FURTHER INFORMATION IN THIS
REGARD I DECIDED AGAINST EXPANDING CURRENT WARNING. WINDS HAVE
OCCASIONALLY HIT ADVISORY CRITERIA IN THE NW...HOWEVER THESE
CONDITIONS HAVE BEEN SPORADIC...SO IVE LEANED AGAINST ISSUANCE OF
WIND ADVISORY.
TONIGHT A SHORTWAVE TROUGH WILL ROUND THE BASE OF THE LARGE SCALE
UPPER LOW WITH A COLD FRONT DROPPING SOUTH OVER OUR CWA (06 TO 09Z).
WHILE WINDS MAY DECREASE SOME AFTER SUNSET...THE LULL IN WINDS THIS
EVENING WILL BE SHORT LIVED BEFORE NEAR ADVISORY LEVEL WINDS
REDEVELOP AFTER MIDNIGHT AND CONTINUE THROUGH THE DAY SATURDAY
BEHIND THE FROPA. SOME GUIDANCE IS ALSO SHOWING BETTER MID LEVEL
MOISTURE WITH THIS UPPER LEVEL TROUGH ROTATING INTO THE
CWA...HOWEVER THE BEST LIFT IS OUTSIDE OUR CWA...AND MODELS NEVER
INITIATE SHOWERS OVER OUR CWA WITH DRY LOW LEVELS STILL IN PLACE.
OTHER THAN THICKENING CLOUD COVER...I AM NOT EXPECTING ANY PRECIP.
OVERNIGHT LOWS TONIGHT WILL DROP TO THE LOW 40S IN EASTERN COLORADO
TO THE LOW 50S IN NORTH CENTRAL KANSAS. CONSIDERING THE COOL NATURE
OF THE AIR MASS WE WOULD BE LOOKING AT MUCH COLDER TEMPS IF IT WASNT
FOR CLOUD COVER AND WINDS OVERNIGHT. HIGHS ON SATURDAY MAY STRUGGLE
TO REACH THE UPPER 60S/70F IF CLOUD COVER FAILS TO CLEAR BY THE
AFTERNOON AS CURRENTLY ADVERTISED.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 152 PM MDT FRI MAY 31 2013
FOR SATURDAY NIGHT THROUGH SUNDAY NIGHT...THE UPPER LEVEL RIDGE WILL
BEGIN TO MOVE OVER THE AREA SATURDAY NIGHT AS A SURFACE HIGH MOVES
INTO THE AREA. SUNDAY THE SURFACE HIGH WILL SLIDE EAST. AS IT DOES
SO A TIGHT PRESSURE GRADIENT WILL DEVELOP OVER THE AREA FROM WEST TO
EAST BEHIND THE EXITING SURFACE HIGH. WINDS WILL BREEZY BUT WILL
DECLINE BEFORE SUNSET AS TEMPERATURES COOL. SUNDAY EVENING AS THE UPPER
LEVEL RIDGE AXIS MOVES EAST OF THE AREA A SHORT WAVE TROUGH WILL
MOVE ACROSS THE AREA. POINT SOUNDINGS SHOW A VERY SMALL AMOUNT OF
ELEVATED INSTABILITY OVER THE SOUTHWEST PART OF THE AREA AS THE
SHORT WAVE MOVES THROUGH. AT THIS TIME WILL KEEP THE FORECAST DRY DUE
TO LOW CONFIDENCE THAT ANY STORMS WILL DEVELOP GIVEN THE ELEVATED
CAPE IS LESS THAN 200 J/KG...AND THE DEEP DRY LAYER EXTENDING UP TO
600MB OR SO WHICH WILL CAUSE ANY LIGHT RAIN THAT MAY DEVELOP TO
EVAPORATE.
MONDAY THROUGH FRIDAY AN UPPER LEVEL TROUGH WILL MOVE ACROSS THE
NORTHERN PLAINS. MODELS HAVE SHIFTED THE TRACK OF THE TROUGH
SLIGHTLY NORTH...BUT OVERALL THIS SEEMS TO HAVE LITTLE EFFECT ON
PRECIP. CHANCES FOR THE PERIOD. NUMEROUS SHORT WAVE TROUGHS THAT
EXTEND FROM THE MAIN FEATURE MOVE OVER THE AREA TROUGH THE PERIOD AS
THE TROUGH SLOWLY MOVES EAST OVER THE NORTHERN PLAINS. WITH EACH
SHORT WAVE TROUGH MOVING THROUGH THE AREA PRECIP. CHANCES WILL
RETURN.
TEMPERATURES FOR THE PERIOD WILL START OUT 10 DEGREES ABOVE NORMAL
MONDAY THEN COOL TO NEAR NORMAL TUESDAY THROUGH FRIDAY AS A COLD
FRONT MOVES THROUGH THE AREA SOMETIME ON TUESDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1112 PM MDT FRI MAY 31 2013
COLD FRONT WILL CONTINUE TO MOVE THROUGH THE REGION OVERNIGHT WITH
GUSTY NORTHWEST WINDS BEHIND IT. WINDS WILL INCREASE A BIT AFTER
SUNRISE WITH MIXING AND CONTINUE TO BE WINDY THROUGH SUNSET
SATURDAY. THERE WILL BE OCCASIONAL MID AND HIGH CLOUDINESS THROUGH
THE PERIOD.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...DR
LONG TERM...JTL
AVIATION...024
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
309 AM EDT SAT JUN 01 2013
.Short Term (Now through Sunday)...
Issued at 309 AM EDT Sat Jun 01 2013
Rather complex forecast unfolding early this morning, as incoming
convection casts quite a bit of uncertainty onto the forecast for
this afternoon into the overnight hours. All of this action is in
response to an expansive upper-level low, which will accelerate into
the Great Lakes this afternoon. An associated cold front will slide
through the region this evening through the overnight hours,
allowing drier and cooler conditions to work in for Sunday.
An expansive MCS continues to slide southeast across portions of
Missouri/Illinois/Indiana this morning. This activity continues to
be fueled by a 40-50 knot low-level jet, supplying copious amounts
of moisture. Some of this activity has briefly caused some
marginally severe wind gusts. However, 0-3km shear vectors oriented
mainly parallel to the cold pool is prohibiting intense upright
convection along the gust front, thus keeping the severe threat
rather isolated. Nonetheless, an isolated severe storm or two
cannot be ruled out within small bowing segments as it approaches
from the northwest early this morning.
The major question then becomes how quickly this morning activity
dissipates/pushes east, and what effect that will have on
instability this afternoon and evening. Guidance is all over the
place, with the latest RAP guidance still depicting 2500 J/kg of
MLCAPE developing late this afternoon ahead of the cold front.
Think the NAM/GFS are more realistic, painting anywhere from about
800-1400 J/kg by late this afternoon. This parameter will be
paramount in determining the severe risk throughout the day, as
lingering clouds/precipitation through the day will largely mitigate
the severe risk. Most of the hi-res guidance focuses the best
instability across southern Kentucky, as this area is most likely to
be unaffected by this approaching morning MCS. This will create a
split across the CWA, with the better dynamics focused across
southern IN/northern KY, while the best instability will reside
across southern Kentucky. Regardless, as the main shortwave ejects
out of the larger scale trough and spreads height falls over the
synoptic cold front, widespread convection looks to break out late
this afternoon into the evening, especially across southern KY.
0-6km shear of 30-40 knots will favor organized convection across
the entire region. The accelerating cold front and large-scale
forcing for ascent will favor mainly a linear storm mode, although a
transient supercell structure will be possible as storms initially
develop. 0-1km shear values of 25-35 knots will promote at least
some tornado risk, although surface winds do not appear as if they
will be quite as backed (SSE) as was suggested in previous model
runs, thus lower 0-1SRH is forecast. Large hail will also be
possible, especially across southern Kentucky where the best
instability will reside, but the expected QLCS storm mode may temper
that threat as well. The bottom line: The severe threat will
largely hinge on afternoon destabilization. If we can destabilize,
a severe QLCS capable of mainly damaging winds will materialize.
Large hail and a few isolated tornadoes will also be possible. Stay
tuned to the forecast throughout the day as the details regarding
the decaying MCS and resulting instability become more apparent.
The synoptic cold front will push through by Sunday evening. Some
guidance is showing the potential for a few showers across southern
IN as the main trough axis swings through Sunday evening, but will
keep the forecast dry for now as moisture looks limited. Highs
Sunday will reach the upper 70s to lower 80s with westerly flow.
.Long Term (Sunday Night - Friday)...
Issued at 230 AM EDT Sat Jun 1 2013
No major changes, as an exiting front will bring lingering rains
only over the far eastern forecast area, as an upper trough passes.
Forecast highs for Monday will be roughly 5 degrees below normal,
under a brief thickness minimum that will allow for pleasant
readings through Tuesday. Upper ridge builds in Wednesday, so kept
low/nil rain chances through at least then, but temperatures will go
over climo slightly by the end of the work week. Lows will rise
uniformly Wednesday through Friday. Morning readings should start to
go above normal Thursday. Storm chances enter the picture again as
heights fall and moisture increases Thursday and Friday. Coverage
should be scattered, mainly during peak heating.
&&
.Aviation (06Z TAF Issuance)...
Issued at 116 AM EDT Sat Jun 01 2013
Rather complex forecast this TAF period, as several rounds of
convection look to impact all terminals. In the near term, current
convection across Missouri/Illinois will continue toward TAF sites
overnight, entering into KSDF and KBWG during the pre-dawn hours.
Quite a bit of uncertainty still exists on just how strong this line
of showers/storms will be as it pushes in, thus will continue to
carry prevailing -SHRA with VCTS. Will amend with prevailing TS as
warranted once confidence increases in thunderstorms reaching these
TAF sites.
After this initial round of thunderstorms moves through,
precipitation should mostly taper off to some light shower activity
for a few hours as the atmosphere recovers. However, by the late
morning into the afternoon hours, instability will once again build
and storms will redevelop. These storms will generally be scattered
through the early afternoon hours, but a more concentrated line
should develop across southern Indiana by the late afternoon,
pushing southeast through all sites through the evening and
overnight hours. Unfortunately, precise timing is still unknown as
all development largely hinders on this morning`s convection, thus
will continue with VCTS wording over a rather broad timeframe. Any
storm that develops from this morning into the overnight hours will
carry gusty winds and heavy rain which will drop sites into MVFR/IFR
categories.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
KY...NONE.
$$
Short Term.......KD
Long Term........RJS
Aviation.........KD
AREA FORECAST DISCUSSION
NWS JACKSON KY
145 AM EDT SAT JUN 1 2013
.UPDATE...
ISSUED AT 145 AM EDT SAT JUN 1 2013
ISOLATED TO SCATTERED SHOWERS ARE JUST STARTING TO BLOSSOM NORTH OF
THE AREA NEAR THE OHIO RIVER. THIS ACTIVITY APPEARS AS IT WILL STAY
TO OUR NORTH...BUT WILL BEAR WATCHING OVER THE NEXT FEW HOURS TO SEE
IF SHOWERS CONTINUE TO DEVELOP SOUTHWARD AND COULD IMPACT OUR
NORTHERN COUNTIES OVERNIGHT. OTHERWISE...CONVECTION ASSOCIATED WITH
THE COLD FRONT REMAINS WELL OFF TO OUR NORTH AND WEST AND NONE OF THE
HI-RES MODELS BRING THIS ACTIVITY INTO OUR AREA UNTIL AT LEAST LATER
THIS MORNING. THUS...GOING TO KEEP FORECAST DRY FOR NOW...AND
CONTINUE TO MONITOR THE DEVELOPMENT TO OUR NORTH. VERY LITTLE CHANGES
WERE MADE TO THE OVERALL FORECAST AT THIS TIME.
UPDATE ISSUED AT 938 PM EDT FRI MAY 31 2013
REMOVED POPS ACROSS MUCH OF THE REGION...WITH ONLY A SLIGHT CHANCE IN
THE FAR NORTHERN SECTIONS OVER THE NEXT COUPLE OF HOURS. BOTH JKL AND
NEIGHBORING OFFICES ARE SHOWING DRY CONDITIONS...WITH LITTLE IN THE
WAY OF EXPECTED REDEVELOPMENT DURING THE REMAINDER OF THE NIGHT. ALL
OTHER WEATHER VARIABLES SEEM TO BE ON TRACK...SO OPTED TO KEEP WITH
PREVIOUS FORECAST.
UPDATE ISSUED AT 600 PM EDT FRI MAY 31 2013
BASED ON CURRENT RADAR WENT AHEAD AND INCREASED POPS FOR NORTHWESTERN
COUNTIES IN THE AREA...WITH THE POTENTIAL FOR SOME SCATTERED SHOWERS
OVER THE NEXT HOUR OR TWO ALONG THE FAR SOUTHWESTERN COUNTIES AS
WELL. THAT BEING SAID...LOOKING AT MODEL PARAMETERS...DYNAMICS SEEM TO BE
FAIRLY WEAK OVER MUCH OF EASTERN KY...AND HI RES MODEL /HRRR/ PRECIP
SHOWS A QUICK DIMINISHING TREND THROUGHOUT THE EVENING. TRIED TO
REFLECT THIS IDEA WITHIN THE POPS AND WX...WITH THE BEST CHANCE FOR
CONVECTION REMAINING OVER THE NORTHERN COUNTIES THROUGH THE EVENING.
BUT WITH VERY LITTLE LIGHTNING SHOWING UP ON RADAR AND WEAK
INSTABILITY IN OUR AREA...ONLY SLIGHT CHANCE OF THUNDER WAS
WARRANTED.
&&
.SHORT TERM...(THIS EVENING THROUGH SATURDAY NIGHT)
ISSUED AT 320 PM EDT FRI MAY 31 2013
MESOSCALE CONVECTIVE VORTEX WHICH HAD BEEN NEAR MADISONVILLE KY AT
1230 PM HAS PULLED NORTHEAST AND IS NOW NEAR LOUISVILLE. STRONGEST
CONVECTION HAS BEEN OCCURRING AHEAD OF THIS FEATURE AND NOW PULLING
INTO SOUTHWEST OH. CONVECTION TRAILS SOUTH TO WEST OF LAKE CUMBERLAND
ALONG OLD OUTFLOW BOUNDARY. WITH THE MOVEMENT OF THIS CONVECTION NNE
IT HAS ONLY BEEN VERY SLOWLY NEARING THE SW PART OF FORECAST AREA.
HOWEVER...OUTFLOW FROM THIS COULD STILL SERVE AS TRIGGER FOR
CONVECTION OVER THE FAR WEST PART OF FORECAST AREA. THE HRRR HAS BEEN
PERSISTENT IN TRYING TO BRING CONVECTION INTO OUR AREA...WITH THE 17Z
RUN TRYING TO MOVE CONVECTION INTO THE AREA AFTER 22Z...AND THEN SLOWLY
DISSIPATING AS IT MOVES EAST. WITH THE MCV MOVING AWAY AND WITH LOSS
OF DAYTIME HEATING DO EXPECT ANY CONVECTION IN OUR AREA TO DECREASE
QUICKLY THIS EVENING AND WILL DROP SHOWERS AND THUNDERSTORMS FROM
FORECAST AFTER MIDNIGHT.
A SHORT WAVE MOVING OUT OF THE SOUTHERN PLAINS SHOULD TRIGGER MORE
CONVECTION OVER MO TONIGHT...WITH THE EFFECTS OF THIS REMAINING TO
OUR WEST OVERNIGHT INTO SATURDAY MORNING. SATURDAY WILL BRING A
CHANCE FOR MORE SHOWERS AND THUNDERSTORMS WITH ANY OUTFLOW
BOUNDARIES FROM OVERNIGHT CONVECTION TO OUR WEST POSSIBLY SERVING AS
TRIGGER FOR MAINLY AFTERNOON SHOWERS AND THUNDERSTORMS ON SATURDAY.
IT IS STILL POSSIBLE SOME OF THE STORMS SATURDAY AFTERNOON AND
EVENING COULD BECOME SEVERE...WITH GREATER INSTABILITY DURING THE
AFTERNOON INTO THE EVENING.
MODELS HAVE TRENDED TOWARDS A QUICKER SOLUTION WITH CONVECTION AHEAD
OF THE COLD FRONT MOVING INTO THE AREA SATURDAY NIGHT. WE HAVE
FOLLOWED THIS IDEA WITH LIKELY SHOWER AND THUNDERSTORM PROBABILITIES
AREA WIDE FOR SATURDAY NIGHT.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 320 PM EDT FRI MAY 31 2013
A COLD FRONT SHOULD BE ABOUT READY TO ENTER THE FORECAST AREA FROM
THE NW AT THE START OF THE PERIOD...WITH SUPPORT FROM AN APPROACHING
UPPER TROUGH...AND A RIBBON OF HIGHER DEW POINTS OFF THE GULF ALONG
THE FRONT BEING ADVECTED ALONG BY A 30-40 KT LOW LEVEL FLOW JUST OFF
THE SURFACE. ALL THIS CONSIDERED...THERE WILL LIKELY BE AN ONGOING
CONVECTIVE EVENT...WITH MODELS SHOWING THE GREATEST LIKELIHOOD OF
THIS IN THE SE PART OF THE AREA. AS THE FRONT SLOWLY PUSHES INTO AND
THROUGH THE FORECAST AREA SUNDAY AND SUNDAY EVENING...THERE COULD
ALSO BE ADDITIONAL DEVELOPMENT...WITH THE GREATEST OPPORTUNITY FOR
THIS IN THE SE WHERE FROPA WILL OCCUR LAST. THE LAST OF ANY
LINGERING PRECIP SHOULD END SUNDAY NIGHT OR EARLY MONDAY AS THE
FRONT CONTINUES ON TO OUR SE.
HIGH PRESSURE OVER THE MIDWEST WILL SUPPLY NOTICEABLY DRIER AND
SOMEWHAT COOLER AIR EARLY IN THE WEEK UNDER WNW FLOW ALOFT. RIDGING
ALOFT WILL PASS OVER ON TUESDAY INTO WEDNESDAY...WITH THE SURFACE
HIGH SHIFTING EASTWARD. THIS WILL BRING A CONTINUATION OF DRY
WEATHER...BUT WITH WARMING ALREADY OCCURRING AND AN EVENTUAL
INCREASE IN SURFACE MOISTURE.
AFTER THIS...MODEL DIFFERENCES BETWEEN THE GFS AND ECMWF BECOME MORE
APPARENT LATE IN THE WEEK. THE ECMWF DEVELOPS AN UPPER RIDGE OVER
THE CAROLINAS...BUT THIS FEATURE IS LACKING IN THE OPERATIONAL GFS.
ALL MODELS INDICATE AN UPPER LOW HEADING EAST ALONG THE CANADIAN
BORDER AND INTO ONTARIO...WITH A SOUTHWARD EXTENDING TROUGH. THE 00Z
ECMWF DOES NOT ALLOW AS MUCH OF A SOUTHERN EXTENSION OF THIS TROUGH
DUE TO ITS CAROLINA RIDGE. THE RESULT IS THAT THE GFS DEVELOPS
CONVECTION OVER THE LOCAL AREA FROM WEDNESDAY ON. MEANWHILE...THE
ECMWF SHOWS LIGHT PRECIP ONLY ON THURSDAY AS THE TROUGH SCOOTS BY TO
OUR NORTH. THE GEM AND GFS ENSEMBLE MEAN SUPPORT THE OPERATIONAL
GFS...AND PREFER TO WEIGHT THE FORECAST TOWARD IT...WITH JUST A BIT
OF ECMWF INFLUENCE TO KNOCK THE POPS DOWN SLIGHTLY FROM WHERE THEY
WOULD OTHERWISE BE.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 145 AM EDT SAT JUN 1 2013
VFR CONDITIONS WILL LIKELY HOLD FOR MUCH OF THE AREA OVER THE NEXT 24
HOURS. THE THREAT FOR SHOWERS AND STORMS WILL INCREASE TODAY AS A
COLD FRONT APPROACHES THE AREA. THIS THREAT WILL INCREASE TONIGHT AND
SUNDAY AS THIS FRONT SLIDES ACROSS THE AREA. THIS WILL BRING
WIDESPREAD SHOWER AND THUNDERSTORMS TO EASTERN KENTUCKY. A FEW OF THE
STRONGER STORMS COULD PRODUCE SOME STRONG WIND GUSTS AND PERHAPS
BRIEFLY DROP VISIBILITIES AND CEILINGS TO MVFR. HOWEVER...NOT
PLANNING TO INCLUDE SPECIFICS ON TIMING AT THIS TIME AS CONVECTION IS
STILL WELL UPSTREAM.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...KAS
SHORT TERM...SBH
LONG TERM...HAL
AVIATION...KAS
AREA FORECAST DISCUSSION
NWS CARIBOU ME
120 AM EDT SAT JUN 1 2013
.SYNOPSIS...
A COLD FRONT WILL DROP SOUTH INTO NORTHERN MAINE TONIGHT. THE
FRONT WILL LIFT BACK TO THE NORTH AS A WARM FRONT LATE SATURDAY
NIGHT. A STRONG COLD FRONT WILL APPROACH FROM THE WEST LATE IN THE
DAY SUNDAY AND VERY SLOWLY CROSS THE REGION SUNDAY NIGHT THROUGH
MONDAY NIGHT.&&
.NEAR TERM /THROUGH TODAY/...
UPDATE 0110L: BACKDOOR COLD FRONT ACROSS XTRM NRN MAINE ATTM W/
SHOWERS/ISOLD THUNDER CONTG ACROSS OUR NRN ZNS 1/2 ATTM. REST OF
THE FA RATHER QUIET THO THERE IS AN ISOLD TSTM CURRENTLY TRACKING
EWRD ACROSS CENTRAL AREAS JUST S OF KMLT ATTM. ADJUSTED POPS TO
BETTER FIT CURRENT AND EXPECTED TRENDS AND HAVE XTND MENTION OF
THUNDER ACROSS THE N THRU THE OVRNGT HRS. ALSO MADE A SMALL
ADJUSTMENT TO THE HRLY TEMPS TO BETTER FIT CURRENT CONDS. FLS
ACROSS NWRN MAINE WILL CONT FOR NOW THO FFMP AND RADAR TRENDS
SHOW MOST SIGNIFICANT PRECIP HAS SHIFTED JUST NNE OF THIS AREA...
1045 PM UPDATE: BASED ON FOG BEING REPORTED AT KFVE AIRPORT...WE
WENT AHEAD AND PLACED PATCHY FOG IN THE NRN PORTION OF THE FA
HAVEN RECEIVED CONVECTIVE RNFL FROM THE MCS THAT CROSSED THE REGION
EARLIER THIS EVE. THE REST OF THE NEAR TERM FCST REMAINS UNCHANGED
FROM LAST UPDATE.
845 PM UPDATE: MOST...IF NOT ALL OF THE STRONG TSTM ACTIVITY HAS
WEAKENED ACROSS OUR FA...SO WE DROPPED THE ENHANCED TSTM WORDING
AND KEEP MENTION OF TSTMS IN FCST TIL ABOUT MDNGT. AN AREA OF MORE
STRATIFORM RNFL BEHIND WHATS LEFT THE LEADING CONVECTION IS STILL
CONTG OVR NRN PTNS OF THE FA THIS EVE...BUT THIS TOO SHOULD
GRADUALLY WIND DOWN BY LATE TNGT. ONLY OTHER CHG WAS TO LOWER
OVRNGT LOWS ACROSS THE N POSTED AT 5 AM SAT DUE TO 8 PM OBS ALREADY
CLOSE TO PRIOR LOWS DUE TO RN COOLED AIR. WITH MID CLD CVR XPCTD
TO CONT SPCLY ACROSS THE N...WE DID NOT INCLUDE PATCHY FOG FOR
LATE TNGT OVR AREAS THAT HAVE EXPERIENCED RNFL THIS EVE...BUT THIS
CANNOT BE RULED OUT IF BREAKS IN THE MID CLD CVR OCCUR AFT MDNGT.
515 PM UPDATE: WE UPDATED POPS TO INCREASE TO CATEGORICAL RANGE
FOR NRN ME TO ACCOUNT FOR THE LN OF TSTMS MOVG IN FROM QB.
ENHANCED WORDING FOR DAMAGING WINDS...HAIL AND HEAVY DOWNPOURS
WERE INCLUDED TIL 11 PM...AT WHICH POINT...THE HRRR MODEL INDICATES
THAT MOST OF THE STRONG TSTM ELEMENTS WILL HAVE MOVED SE INTO NB.
ALSO UPDATED QPF FOR THE 18-24Z AND 00-06Z TM FRAMES TNGT TO
INCREASE TO CVR CONVECTIVE RNFL RATES WITH THIS LN. 1-3 HR FLASH
FLOOD GUIDANCE IS ONLY ABOUT 1.50 INCHES FOR MOST OF NRN ME...SO
WE WILL BE MONITORING FOR POSSIBLE LCLZD FLOODING AS WELL.
ORGNL DISC: A VERY WARM AND HUMID AIR MASS WILL REMAIN IN PLACE
THROUGH TONIGHT. A COLD FRONT WILL SAG SOUTHWARD OUT OF QUEBEC
INTO THE SAINT JOHN VALLEY THIS EVENING AND BRING THE THREAT OF
STRONG OR SEVERE THUNDERSTORMS WITH DAMAGING WINDS AND SMALL HAIL.
WITH STRONG WINDS ALOFT AND FAST STORM MOTIONS...SOME BOWING LINE
SEGMENTS ARE POSSIBLE AS THIS CONVECTION ENTERS THE NORTHERN END
OF THE CWA THIS EVENING. DOWNED TREES WERE ALREADY REPORTED WITH A
WEAKER THUNDERSTORM IN FORT KENT THIS AFTERNOON. DEEPER STORMS MAY
ALLOW FOR UP TO QUARTER SIZE HAIL BRIEFLY. WITH PWATS OVER ONE AND
HALF INCH...HEAVY DOWNPOURS ARE EXPECTED. THESE STORMS COULD REACH
40K FT. THE SEVERE WEATHER THREAT SHOULD BE RESTRICTED PRIMARILY
TO ZONES ONE AND TWO IN NORTHERN AROOSTOOK WITH STORMS WEAKENING
BY THE TIME THEY REACH HOULTON LATER THIS EVENING.
ELSEWHERE IN THE FORECAST AREA...AIR MASS THUNDERSTORMS WILL END
LATER THIS AFTERNOON AND A WARM AND HUMID NIGHT IS EXPECTED WITH
LOWS IN THE UPPER 60S FOR DOWN EAST AND AROUND BANGOR. LOWS WILL
BE IN THE LOW 60S TOWARDS THE CROWN OF MAINE. THE COLD FRONT WILL
STALL IN NORTHERN MAINE WITH CLOUD COVER AND THUNDERSTORMS
PERSISTING WELL INTO THE NIGHT.
&&
.SHORT TERM /TONIGHT THROUGH 6 PM SUNDAY/...
ACTIVE WEATHER IS EXPECTED DURING THE SHORT TERM WITH THE MAIN
CONCERNS THE POTENTIAL FOR STRONG TO SEVERE THUNDERSTORMS AND FLASH
FLOODING.
A FRONTAL BOUNDARY IS EXPECTED TO STRETCH ACROSS THE CENTRAL
PORTION OF THE CWA SAT EVENING. THE FRONT SHOULD LIFT BACK TO THE
NORTH AS A WARM FRONT SAT NIGHT AND SHOULD BE ACCOMPANIED BY
SHOWERS AND EMBEDDED THUNDERSTORMS...ESPECIALLY ACROSS THE
NORTHERN HALF OF THE AREA. PRECIPITABLE H20 IS PROGGED TO BE
AROUND 1.6-1.8 INCHES WHICH IS NEAR RECORD LEVELS FOR JUNE 1ST.
SHOWERS AND THUNDERSTORMS SAT NIGHT WILL HAVE THE POTENTIAL OF
PRODUCING HEAVY DOWNPOURS...AND DURING THE EVENING GUSTY WIND AND
SMALL HAIL. A STRONG COLD FRONT WILL APPROACH THE WESTERN BORDER
OF MAINE LATE IN THE DAY SUNDAY. THE MODELS DIFFER ON THE AMOUNT
OF INSTABILITY THAT WILL BE AVAILABLE SUN PM...AND MUCH WILL
DEPEND ON CLOUD COVER/PRE-EXISTING SHOWERS THAT COULD LIMIT JUST
HOW UNSTABLE IT BECOMES DURING THE AFTERNOON. THE MODELS DO
INDICATE ENOUGH CAPE AND SHEAR THAT SEVERE STORMS WILL BE POSSIBLE
DURING THE AFTERNOON/EVENING. THE HIGH PWATS ALSO MEAN THAT HEAVY
DOWNPOURS AND FLASH FLOODING WILL BE CONCERNS TOO...ESPECIALLY
GIVEN HOW SATURATED THE GROUND IS FROM THE RECENT HEAVY RAINS. THE
ENHANCED WORDING THAT THE MIDNIGHT CREW HAD IN LOOKS REAL GOOD AND
THE ONLY CHANGE WAS TO ADD THE LOCALLY HEAVY RAIN WORDING FOR SUN
PM/EVE. THE COLD FRONT IS EXPECTED TO ONLY VERY SLOWLY MOVE ACROSS
THE CWA SUN NIGHT AND MON AND MAY ONLY BE ON A HOULTON-BANGOR LINE
BY MON EVENING. THE BEST CHANCE OF SHOWERS AND THUNDERSTORMS
MONDAY WILL LIKELY BE ACROSS THE SOUTHEAST OF THE CWA WITH SOME
DRYING TO BEGIN TO WORK INTO THE WESTERN ZONES. WILL AGAIN MENTION
HEAVY RAIN POSSIBLE ACROSS THE SOUTHEAST HALF OF THE CWA. WILL
HOLD OFF ON ANY ENHANCED SEVERE WEATHER LANGUAGE AS IT IS IN DAY
THREE. THE SPC DOES HAVE MUCH OF THE AREA IN A SLIGHT RISK FOR DAY
3.
&&
.LONG TERM /SUNDAY NIGHT THROUGH SATURDAY/...
THE EXTENDED MODELS CONTINUE TO BE IN GOOD AGREEMENT THROUGH THE
EARLY AND MID PORTIONS OF THE EXTENDED. A LOW PRESSURE SYSTEM SE
OF JAMES BAY...WITH AN ASSOCIATED FRONTAL SYSTEM EXTENDING SOUTH
THROUGH DOWNEAST MAINE...THEN SOUTH ALONG THE ATLANTIC COAST. A
BERMUDA HIGH PRESSURE SYSTEM RIDGED INTO THE COAST...A SECOND HIGH
PRESSURE SYSTEM BUILDING SE OUT OF WRN CANADA. BY THE START OF THE
EXTENDED PERIOD THE NRN PORTIONS OF THE FRONT CONTINUES TO REMAIN
UNDER THE UPPER LEVEL RIDGE...THE SRN PORTION HOWEVER WILL BEGIN
TO MOVE OUT AS THE UPPER TROUGH MOVES TO THE EAST SIDE OF THE
APPALACHIANS. BOTH MODELS INDICATE A SECONDARY LOW DEVELOPING
ALONG COAST VA WHICH WILL ASSIST WITH THE EASTWARD MOVEMENT OF
THE FRONT. BY WED MRNG THE FRONT WILL BE WELL EAST OF THE
AREA...AND HIGHER PRESSURE WILL BUILD INTO MAINE. THE HIGH
PRESSURE RIDGE WILL REMAIN IN PLACE THROUGH AT LEAST FRI MRNG. FRI
MRNG A NEW LOW PRESSURE SYSTEM WILL BE CENTERED OVER THE GREAT
LAKES...WITH ITS SUPPORTING UPPER LOW OVER CENTRAL MANITOBA. THE
GFS SHOWS A WARM FRONT EXTENDED EAST INTO WRN MAINE. THE ECMWF FRI
MRNG MAINTAINS THE HIGH PRESSURE RIDGE WITH NO APPARENT WARM FRONT
ASSOCIATED WITH THE FRONT. BY FRI EVENING THE ECMWF SYSTEM BECOMES
A BIT MORE ORGANIZED WITH ITS UPPER LOW MOVING TO SW JAMES BAY.
BY SAT MRNG BOTH MODELS MOVE THE SHOWERS ASSOCIATED WITH THE LOW
INTO MAINE.
STARTED WITH A BASE OF GMOS...OVER LAID A BLEND OF OFFICIAL/ALL
MODEL BLEND FOR WNDS/POPS/SKY/MAX/MIN. ADDED 15 PERCENT TO WINDS
FOR GUSTS OVER LAND...25 PERCENT TO WINDS OVER COASTAL WATERS.
&&
.AVIATION /05Z SATURDAY THROUGH WEDNESDAY/...
NEAR TERM: VFR OUTSIDE OF THUNDERSTORMS LATE THIS AFTERNOON AND
EVENING. THUNDERSTORMS COULD BE SEVERE TOWARDS CAR...PQI AND FVE THIS
EVENING WITH DAMAGING WINDS AND SMALL HAIL. THE FRONT WILL STALL
AND COULD PRODUCE IFR VIS AND CIGS FROM PQI NORTHWARD INTO EARLY
SATURDAY MORNING. OTHERWISE...VFR CONDITIONS ARE EXPECTED.
SHORT TERM: VFR MUCH OF THE TIME SAT NIGHT THROUGH MONDAY...BUT A
PERIOD OF MVFR TO IFR POSSIBLE SAT NIGHT FROM KHUL NORTH IN SHOWERS
AND THUNDERSTORMS. ADDITIONAL PERIODS OF MVFR AND BRIEF IFR
POSSIBLE IN ANY NEAR CONVECTION SUN PM AND AGAIN MONDAY. STRONG AND
ERRATIC WIND GUSTS AND HAIL WILL BE POSSIBLE IN/NEAR THE STRONGEST
CONVECTION.
&&
.MARINE...
NEAR TERM: FOG IS EXPECTED TO RETURN LATER TONIGHT AND TOMORROW ON
THE WATERS. OTHERWISE...STABLE CONDITIONS MEAN LIGHT WINDS AND A
SOUTH SWELL AROUND 2 TO 3 FEET.
SHORT TERM: A SW WIND WILL PICK UP OUT AHEAD OF A COLD FRONT SUNDAY
AND MAY REACH SCA LEVELS BY SUN PM AND CONTINUE INTO MONDAY. THE
SEAS WILL LIKELY REACH SCA LEVELS BY SUNDAY AFTERNOON AND CONTINUE
INTO MONDAY WITH A SOUTH SWELL AND A COMBINED SEA/SWELL OF 8-10 FEET
EXPECTED BY SUNDAY NIGHT.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...KHW
SHORT TERM...CB
LONG TERM...NORTON
AVIATION...KHW/CB
MARINE...KHW/CB
AREA FORECAST DISCUSSION
NWS SPRINGFIELD MO
723 PM CDT FRI MAY 31 2013
.MESOSCALE DISCUSSION...
ISSUED AT 712 PM CDT FRI MAY 31 2013
THE TORNADO WATCH THAT IS IN EFFECT UNTIL 10 PM FOR AREAS NORTH
OF INTERSTATE 44 HAS BEEN EXTENDED SOUTH TO THE ARKANSAS BORDER
AND ALONG AND WEST OF HIGHWAY 65. SEVERAL STRONG SUPERCELLS HAVE
FORMED OVER NORTHEASTERN OKLAHOMA...AND ARE TRACKING TOWARD THE
NEWLY WATCHED AREA. IN PARTICULAR...ONE PARTICULARLY WELL
ORGANIZED SUPERCELL IS EXPECTED TO TRACK ALONG THE OKLAHOMA
KANSAS BORDER INTO FAR SOUTHWESTERN MISSOURI. ADDITIONAL STORMS
MAY FOLLOW IT INTO THE AREA. ENVIRONMENTAL PARAMETERS REMAIN
FAVORABLE FOR TORNADIC DEVELOPMENT. MLCAPE VALUES IN EXCESS OF
3000 J/KG...LOW LEVEL HELICITY VALUES EXPECTED TO INCREASE TO
VALUES NEAR 200...AND SUFFICIENTLY LOW LCL HEIGHTS ALL FAVOR THE
POTENTIAL FOR TORNADOES WITH THESES SUPERCELLS. THE 00Z SOUNDING
FROM SPRINGFIELD SHOWS A VERY UNSTABLE AIRMASS WITH NO CAPPING
AND VERY STEEP LAPSE RATES IN THE MID LEVELS. LARGE HAIL AND A
FEW STRONG TORNADOES ARE SUPPORTED BY THIS SOUNDING.
&&
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 1233 PM CDT FRI MAY 31 2013
SEE MESO AFD FOR MORE DETAILS THROUGH TONIGHT. MAIN CONCERN LATE
TONIGHT WILL BE FLOODING/HYDRO ISSUES. A STRENGTHENING LOW LEVEL
JET WILL IMPINGE ON APPROACHING MESOSCALE SFC BOUNDARY. PROGGED
PWATS AROUND 1.75 INCHES WITH CONTINUED LOW LEVEL MOISTURE
ADVECTION WITH THE POTENTIAL FOR A FORWARD PROPAGATING MCS WITH
HEAVY RAINFALL DEVELOPING ON THE OUTFLOW DOMINATE PORTION OF THE
MCS SOMEWHERE OVER THE REGION WHERE STORMS CAN TRAIN ALONG A WSW-
ENE ORIENTED OUTFLOW BOUNDARY. FCST GUIDANCE HAS TARGETED THE MO
OZARK PLATEAU FOR THIS SCENARIO WITH AN EXCESS OF 3-4 INCHES OF
RAIN...BUT CONFIDENCE ON THE PRECISE LOCATION OF THE EXCESSIVE/HEAVY
RAIN WILL BE AN UNFOLDING STORM AND MESOSCALE ISSUE.
THE COLD FRONT WILL FINALLY MOVE THROUGH THE REGION SATURDAY. MAY
HAVE TO WATCH FOR SOME REDEVELOPMENT ALONG THE FRONT AS IT
EXITS...BUT WILL TACKLE THAT LATER ON.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 1233 PM CDT FRI MAY 31 2013
SUNDAY AND MONDAY WILL BE QUIET AND COOL WITH HIGH PRESSURE NOSING
SOUTH INTO THE AREA. ANOTHER UPPER LOW WILL MOVE INTO THE UPPER
PLAINS WITH EMBEDDED SHORTWAVES IN THE W-E UPPER LEVEL FLOW TOWARD
THE MID/LATE WEEK PERIOD WITH INCREASING RAIN CHANCES.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1233 PM CDT FRI MAY 31 2013
CONVECTION CURRENTLY TO THE NORTH OF THE TAF SITES AT 23Z. WILL
GRADUALLY SEE THIS TRANSITION SOUTHEASTWARD TONIGHT...BUT
TRANSITION WILL BE A SLOW ONE. HRRR SEEMS TO HANDLE THIS THIS BEST
AND HAVE USED AS GUIDANCE ON TAKING PRECIPITATION SOUTH THROUGH
THE AREA TONIGHT. EXPECTING VFR CONDITIONS OUTSIDE OF CONVECTION
AND MVFR CONDITIONS WITHIN THE CONVECTION. COLD FRONT SHOULD PUSH
THROUGH THE AREA ON SATURDAY FROM NORTH TO SOUTH.
&&
.SGF WATCHES/WARNINGS/ADVISORIES...
MO...FLASH FLOOD WATCH UNTIL 7 AM CDT SATURDAY FOR MOZ055>058-066>071-
077>083-088>098-101>106.
KS...FLASH FLOOD WATCH UNTIL 7 AM CDT SATURDAY FOR KSZ073-097-101.
&&
$$
MESOSCALE...KARDELL
SHORT TERM...DSA
LONG TERM...DSA
AVIATION...DSA
AREA FORECAST DISCUSSION
NWS ST LOUIS MO
244 PM CDT THU MAY 30 2013
.SHORT TERM...(THROUGH LATE TONIGHT)
ISSUED AT 240 PM CDT THU MAY 30 2013
TORNADO WATCH CONTINUES UNTIL 8 PM. ATMOSPHERE OUTSIDE OF OUTFLOW
COOLED AIR HAS BECOME QUITE UNSTABLE WITH MLCAPES ABOVE 2000 J/KG.
AT THE SAME TIME...DEEP LAYER SHEAR IS INCREASING IN RESPONSE TO
APPROACHING TROUGH CURRENTLY OVER THE CENTRAL PLAINS. THIS TROUGH
IS THE MAIN FOCUS FOR LARGE SCALE ASCENT TONIGHT AND CONSEQUENTLY IT
WILL DETERMINE THE OVERALL PRECIPITATION TRENDS. RAP SHOWS THIS
TROUGH MOVING ACROSS THE CWA AROUND 06Z...SO CURRENT THINKING IS
THAT LINE OF STORMS OVER WESTERN MO WILL CONTINUE TO SLOWLY MOVE
EAST ACROSS THE AREA LATER THIS AFTERNOON AND EVENING.
AFOREMENTIONED INSTABILITY AND SHEAR STILL FAVORS THE POTENTIAL FOR
A FEW SUPERCELLS OR ORGANIZED MULTI-CELLS THAT COULD PRODUCE LARGE
HAIL AND DAMAGING WINDS. LOW LEVEL SHEAR ALSO SUGGESTS THAT ONE OR
TWO TORNADOES COULD FORM IN THE STRONGER STORMS. STILL LOOKS
REASONABLE THAT WESTERN MO LINE WILL EXIT THE EASTERN COUNTIES LATER
THIS EVENING. OUTFLOW FROM THE LINE WILL LIKELY STALL OVER SOUTHERN
MO...SO KEPT CHANCE OF THUNDERSTORMS GOING IN THE SOUTHERN CWA INTO
THE OVERNIGHT HOURS. STILL EXPECT REDEVELOPMENT OF THUNDERSTORMS
OVER WESTERN MO ON THE NOSE OF THE LOW LEVEL JET OVERNIGHT THAT WILL
MOVE INTO NORTHEAST AND CENTRAL MO TOWARD 12Z.
FLASH FLOOD WATCH WILL CONTINUE AS IS. HEAVIEST RAINFALL WILL FOCUS
OVER THE WATCH AREA TONIGHT AND THE SOUTHERN AND EASTERN COUNTIES
HAVE HIGH FLASH FLOOD GUIDANCE. ATMOSPHERE IS VERY MOIST AND DEEP
LAYER FLOW FAVORS TRAINING TONIGHT.
.LONG TERM...(FRIDAY THROUGH NEXT THURSDAY)
ISSUED AT 240 PM CDT THU MAY 30 2013
CONVECTIVE TRENDS ARE SOMEWHAT UNCLEAR FOR FRIDAY MORNING. SOME
GUIDANCE SHOWS LINGERING CONVECTION ACROSS THE EASTERN OZARKS AND
SOUTHERN ILLINOIS. THIS COULD BE POSSIBLE IF THE AFOREMENTIONED OUTFLOW
BOUNDARY FROM THURSDAY NIGHT`S CONVECTION IS STILL IN PLACE OVER
THOSE AREAS. HOWEVER...MOST OF THE GUIDANCE SHOWS A DRYING TREND
BY AROUND 12Z ACROSS THE AREA. THEN...THE LOW LEVEL JET REFOCUSES
BACK OVER NORTHERN/NORTHWESTERN MISSOURI. ALL GUIDANCE SHOWS A
TREMENDOUS AMOUNT OF MOISTURE CONVERGENCE IN THAT AREA STARTING
ABOUT 12Z AND RAIN DEVELOPING BETWEEN 12Z AND 15Z...SPREADING INTO
NORTHEAST MISSOURI/WEST CENTRAL ILLINOIS PROBABLY DURING THE MID
TO LATE MORNING. INSTABILITY WILL BUILD RAPIDLY DURING THE LATE
MORNING WITH MUCAPE EXCEEDING 2500 J/KG ACCORDING TO MOST GUIDANCE
AND DEEP LAYER SHEAR AROUND 50-60KTS SO SEVERE STORMS WILL BE
POSSIBLE AT ANY TIME DURING THE LATE MORNING. HOWEVER...THE MAIN
SHOW WILL LIKELY DEVELOP DURING THE LATE AFTERNOON OR EARLY
EVENING AS ANOTHER LOBE OF VORTICITY WRAPS AROUND THE SOUTH SIDE
OF THE UPPER LEVEL LOW AND PUSHES THE SURFACE FRONT INTO NORTHWEST
MISSOURI. WHATEVER`S LEFT OF THE CAP WILL ALSO BE WIPED AWAY.
AFTERNOON CAPE VALUES LOOK TO BE IN EXCESS OF 3000 J/KG WITH SHEAR
STAYING ABOVE 50KTS. THINK THERE WILL BE SOME DISCRETE STORMS
INITIALLY...BUT WITH LITTLE OR NO CAP AND COPIOUS CAPE WE SHOULD
SEE THE STORMS CONGEAL INTO A LINE. CANNOT RULE OUT ANY KIND OF
SEVERE WEATHER INCLUDING DAMAGING WINDS...LARGE HAIL...AND EVEN
TORNADOES WITH THE LINE. THE LINE SHOULD PROGRESS AT A MODERATE
PACE INTO SOUTHEAST MISSOURI BY EARLY MORNING SATURDAY. OF COURSE
WITH THE HEAVY RAIN POTENTIAL AND NEARLY SATURATED GROUND THERE
WILL BE A CONTINUING FLASH FLOOD THREAT...AND IT`S LIKELY THE
FLASH FLOOD WATCH WILL NEED TO BE EXPANDED EITHER EARLY FRIDAY
MORNING OR FRIDAY AFTERNOON TO COVER THE REST OF THE CWFA.
CURRENT THINKING IS THAT THE INITIAL LINE OF CONVECTION WILL WEAKEN
OVER THE EASTERN OZARKS SATURDAY MORNING. HOWEVER THERE WILL BE
REDEVELOPMENT BY EARLY SATURDAY AFTERNOON...PERHAPS AS FAR NORTHWEST
AS THE COLUMBIA AREA...AS THE SURFACE COLD FRONT FINALLY KICKS INTO
GEAR AND HEADS EAST. SPC STILL HAS THE SOUTHEASTERN 2/3 OF THE CWFA
IN A SLIGHT RISK SATURDAY...INCLUDING THE STL METRO AREA AND POINTS
ALONG AND EAST OF THE I-44/I-55 CORRIDORS. THE UPPER LEVEL
SHORTWAVE FINALLY SWINGS THROUGH SATURDAY AFTERNOON/EARLY EVENING
PUSHING THE COLD FRONT SOUTHEAST INTO THE LOWER
MISSISSIPPI/TENNESSEE VALLEYS.
(SUNDAY THROUGH NEXT THURSDAY)
HIGH PRESSURE IS STILL EXPECTED TO BUILD ACROSS THE MIDWEST SUNDAY
AND CONTROL THE WEATHER AT LEAST THROUGH MONDAY. EXPECTING BELOW
NORMAL TEMPERATURES AND LESS HUMID CONDITIONS THROUGH THAT PERIOD.
MEDIUM RANGE GUIDANCE IS A LITTLE FASTER THAN YESTERDAY IN PUSHING
THE HIGH EAST AWAY FROM THE MID-MISSISSIPPI VALLEY. SOUTHERLY FLOW
RETURNS TUESDAY AND BOTH THE GFS AND ECMWF PRINT OUT PRECIP LATE
TUESDAY THROUGH THURSDAY AS A SHORTWAVE DIPS INTO THE NORTHERN
PLAINS. THE GFS IS MUCH MORE DYNAMIC WITH THIS WAVE THAN THE ECMWF
AND THEREFORE CRANKS OUT A LOT MORE PRECIP. HAVE OPTED TO JUST
STICK WITH CHANCE POPS FOR THIS PERIOD RIGHT NOW. WILL CONTINUE TO
WATCH THIS NEXT WAVE AND INCREASE POPS AS NEEDED IF BOTH MODELS
CONTINUE TO TREND WETTER.
CARNEY
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 136 PM CDT THU MAY 30 2013
MODELS ARE UNCLEAR ON TIMING OF SHOWERS/THUNDERSTORMS FOR EACH
TAF...SO AMENDMENTS WILL BE NECESSARY BASED ON RADAR TRENDS
THE NEXT 12 HOURS. CURRENT THINKING IS THAT THUNDERSTORMS WILL
CONTINUE OVER EASTERN MO/WESTERN IL THE NEXT FEW HOURS...AND THAT
THE LINE OVER WESTERN MO WILL ADVANCE SLOWLY EASTWARD THE REST OF
THE AFTERNOON AND EVENING. STORMS MAY BE SEVERE WITH STRONG WINDS
GUSTS AND HAIL. EXPECT MAINLY VFR CONDITIONS EXCEPT IN THE HEAVIER
CORES WHERE IFR VSBYS/CIGS CAN BE EXPECTED.
SPECIFICS FOR KSTL...THUNDERSTORMS CURRENTLY AROUND LAMBERT WILL
INTERMITTENTLY BRING IFR CONDITIONS IN HEAVY RAIN. CANNOT RULE OUT
HAIL AND STRONG WINDS GUSTS WITH ANY OF THE STRONGER CORES. LINE
OF STORMS CURRENTLY OVER WESTERN MO WILL NOT REACH KSTL UNTIL
AFTER 00Z.
BRITT
&&
.PRELIMINARY POINT TEMPS/POPS...
SAINT LOUIS 71 84 69 81 / 80 60 90 70
QUINCY 67 80 65 77 / 80 80 80 50
COLUMBIA 67 81 66 78 / 80 70 90 50
JEFFERSON CITY 67 82 68 78 / 80 60 90 60
SALEM 69 83 71 81 / 70 50 70 70
FARMINGTON 68 82 69 81 / 70 50 90 70
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...FLASH FLOOD WATCH THROUGH SATURDAY MORNING FOR AUDRAIN MO-BOONE
MO-CALLAWAY MO-COLE MO-FRANKLIN MO-GASCONADE MO-JEFFERSON
MO-KNOX MO-LEWIS MO-LINCOLN MO-MARION MO-MONITEAU MO-MONROE
MO-MONTGOMERY MO-OSAGE MO-PIKE MO-RALLS MO-SHELBY MO-ST.
CHARLES MO-ST. LOUIS CITY MO-ST. LOUIS MO-WARREN MO.
IL...FLASH FLOOD WATCH THROUGH SATURDAY MORNING FOR ADAMS IL-BROWN IL-
CALHOUN IL-GREENE IL-JERSEY IL-MACOUPIN IL-MADISON IL-
MONROE IL-PIKE IL-ST. CLAIR IL.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION...UPDATED
NWS ST LOUIS MO
136 PM CDT THU MAY 30 2013
.UPDATE...
ISSUED AT 136 PM CDT THU MAY 30 2013
TORNADO WATCH IS IN EFFECT FOR THE ENTIRE AREA UNTIL 8 PM. MUCAPES
ARE AROUND 2000 J/KG AND WILL CONTINUE TO RISE OUTSIDE OF OUTFLOW
COOLED AIR THIS AFTERNOON. EFFECTIVE SHEAR HAS IS NOW AROUND 35KTS
WHICH SUGGESTS THAT A FEW SUPERCELLS MAY DEVELOP THIS AFTERNOON...
BUT STILL EXPECT MAINLY MULTI-CELLS CAPABLE OF PRODUCING LARGE
HAIL AND DAMAGING WINDS. LOW LEVEL SHEAR IS STILL IMPRESSIVE WITH
0-1KM SHEAR BETWEEN 20-35KTS...SO A FEW BRIEF TORNADOES ARE
POSSIBLE WITHIN LINES AND IN ANY SUPERCELLS. CONTINUE TO EXPECT
STORMS TO DEVELOP ALONG THE LINE NEAR THE MISSISSIPPI RIVER. MAIN
LINE OVER WESTERN MISSOURI WILL MOVE INTO CENTRAL MO BY MID
AFTERNOON...AND NEAR THE MISSISSIPPI RIVER LATER THIS
AFTERNOON/EARLY EVENING.
BRITT
&&
.SHORT TERM...(THROUGH LATE TONIGHT)
ISSUED AT 1044 AM CDT THU MAY 30 2013
COMPLICATED FORECAST FOR THE REST OF THE DAY AS AREA OF SHOWERS/
THUNDERSTORMS ARE MOVING VERY SLOWLY EASTWARD LATE THIS MORNING.
THIS IS AHEAD OF THE NEGATIVELY TILTED TROUGH CURRENTLY OVER THE
CENTRAL PLAINS THAT THE RAP LIFTS INTO MO/IL THIS EVENING. LAST
FEW RUNS OF THE HRRR SUPPORTS THAT THE WESTERN MO COMPLEX WILL
MOVE NORTHEASTWARD INTO THE CWA BY LATE THIS AFTERNOON/EARLY THIS
EVENING. IN ADDITION...SCATTERED THUNDERSTORMS HAVE RECENTLY
DEVELOPED OVER SOUTH CENTRAL MO THAT ARE LIFTING NORTHEASTWARD.
THESE TRENDS SUPPORT GOING FORECAST THAT PRECIPITATION CHANCES
WILL INCREASE THROUGH THE AFTERNOON. MLCAPES ARE CURRENTLY
1000-1500 J/K AND SHOULD INCREASE IN THE WARM SECTOR AS
TEMPERATURES CLIMB INTO THE LOWER-MID 80S. 0-6KM SHEAR WILL BE
RELATIVELY WEAK WHICH FAVORS MULTICELL STORMS...THOUGH INCREASING
INSTABILITY AND LARGE SCALE LIFT SUGGEST THAT THERE MAY BE A FEW
SEVERE STORMS CAPABLE OF PRODUCING SOME LARGE HAIL AND DAMAGING
WIND GUSTS THROUGH THIS EVENING. THE LOW LEVEL JET WILL REMAIN
40-50KTS TODAY...SO CANNOT RULE OUT A TORNADO OR TWO IN THE STRONGEST
STORMS. LATEST RADAR IMAGERY HAS SHOWN THE TENDENCY FOR CELLS TO
TRAIN...SO HEAVY RAINFALL DOES LOOK LIKE A REAL THREAT GIVEN PWATS
AROUND 1.8 INCHES.
BRITT
.LONG TERM...(TONIGHT THROUGH WEDNESDAY)
ISSUED AT 343 AM CDT THU MAY 30 2013
(TONIGHT THROUGH SATURDAY NIGHT)
PCPN CHANCES INCREASE TONIGHT AS NEXT IN SERIES OF MCS/S DEVELOPS OVER
WESTERN MO AND SLIDES EAST THROUGH FORECAST AREA...WITH BEST
CHANCES OF HEAVY RAIN ALONG AND NORTH OF I-70. SINCE THIS AREA HAS
HAD QUITE A BIT OF RAIN OVER THE PAST WEEK AND SOILS REMAIN
SATURATED...HAVE ISSUED A FLASH FLOOD WATCH FROM 18Z TODAY THROUGH
12Z SATURDAY. LOWS TONIGHT TO REMAIN MILD...IN THE MID 60S TO LOW
70S.
FOR FRIDAY...A LOT WILL DEPEND ON HOW SOON THIS AREA OF STORMS
WEAKENS/EXITS FORECAST AREA...ON WHAT WILL DEVELOP FOR THE AFTERNOON
AND EVENING HOURS. IF ATMOSPHERE GETS WORKED OVER...IT WILL TAKE A
LOT FOR IT TO RECOVER. FOR NOW...WILL ERR ON THE SIDE OF CAUTION
WITH STORMS REDEVELOPING BY THE AFTERNOON HOURS AS NEXT SHORTWAVE
SLIDES THROUGH. WITH DECENT INSTABILITY...MID LEVEL LAPSE RATES AND
STRENGTHENING LOW LEVEL JET...WILL SEE A CHANCE FOR SEVERE WEATHER
ONCE AGAIN FRIDAY AFTERNOON AND OVERNIGHT. ANOTHER ROUND OF HEAVY RAIN
IS POSSIBLE AS WELL...WHICH WILL EVENTUALLY SHIFT TO THE SOUTH WITH
TIME. SO MAY NEED TO EXTEND FLASH FLOOD WATCH TO INCLUDE REST OF
FORECAST AREA.
MAIN COLD FRONT TO FINALLY MOVE THROUGH THE AREA DURING THE DAY ON
SATURDAY WITH LAST IN A SERIES OF SHORTWAVES SLIDING THROUGH...SO
PCPN TO TAPER OFF BY SATURDAY EVENING.
(SUNDAY THROUGH NEXT WEDNESDAY)
COOLER AND DRIER WEATHER IS IN STORE FOR THE LAST PART OF THE
WEEKEND AND INTO EARLY NEXT WEEK. HIGHS WILL BE IN THE UPPER 60S TO
MID 70S SUNDAY THROUGH TUESDAY. THEN NEXT WEATHER SYSTEM TO APPROACH
THE REGION BY MID WEEK WITH NEXT CHANCE FOR SHOWERS AND
THUNDERSTORMS BEGINNING TUESDAY NIGHT.
BYRD
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 136 PM CDT THU MAY 30 2013
MODELS ARE UNCLEAR ON TIMING OF SHOWERS/THUNDERSTORMS FOR EACH
TAF...SO AMENDMENTS WILL BE NECESSARY BASED ON RADAR TRENDS
THE NEXT 12 HOURS. CURRENT THINKING IS THAT THUNDERSTORMS WILL
CONTINUE OVER EASTERN MO/WESTERN IL THE NEXT FEW HOURS...AND THAT
THE LINE OVER WESTERN MO WILL ADVANCE SLOWLY EASTWARD THE REST OF
THE AFTERNOON AND EVENING. STORMS MAY BE SEVERE WITH STRONG WINDS
GUSTS AND HAIL. EXPECT MAINLY VFR CONDITIONS EXCEPT IN THE HEAVIER
CORES WHERE IFR VSBYS/CIGS CAN BE EXPECTED.
SPECIFICS FOR KSTL...THUNDERSTORMS CURRENTLY AROUND LAMBERT WILL
INTERMITTENTLY BRING IFR CONDITIONS IN HEAVY RAIN. CANNOT RULE OUT
HAIL AND STRONG WINDS GUSTS WITH ANY OF THE STRONGER CORES. LINE
OF STORMS CURRENTLY OVER WESTERN MO WILL NOT REACH KSTL UNTIL
AFTER 00Z.
BRITT
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...FLASH FLOOD WATCH THROUGH SATURDAY MORNING FOR AUDRAIN MO-BOONE
MO-CALLAWAY MO-COLE MO-FRANKLIN MO-GASCONADE MO-JEFFERSON
MO-KNOX MO-LEWIS MO-LINCOLN MO-MARION MO-MONITEAU MO-MONROE
MO-MONTGOMERY MO-OSAGE MO-PIKE MO-RALLS MO-SHELBY MO-ST.
CHARLES MO-ST. LOUIS CITY MO-ST. LOUIS MO-WARREN MO.
IL...FLASH FLOOD WATCH THROUGH SATURDAY MORNING FOR ADAMS IL-BROWN IL-
CALHOUN IL-GREENE IL-JERSEY IL-MACOUPIN IL-MADISON IL-
MONROE IL-PIKE IL-ST. CLAIR IL.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS ST LOUIS MO
1044 AM CDT THU MAY 30 2013
.SHORT TERM...(THROUGH LATE TONIGHT)
ISSUED AT 1044 AM CDT THU MAY 30 2013
COMPLICATED FORECAST FOR THE REST OF THE DAY AS AREA OF SHOWERS/
THUNDERSTORMS ARE MOVING VERY SLOWLY EASTWARD LATE THIS MORNING.
THIS IS AHEAD OF THE NEGATIVELY TILTED TROUGH CURRENTLY OVER THE
CENTRAL PLAINS THAT THE RAP LIFTS INTO MO/IL THIS EVENING. LAST
FEW RUNS OF THE HRRR SUPPORTS THAT THE WESTERN MO COMPLEX WILL
MOVE NORTHEASTWARD INTO THE CWA BY LATE THIS AFTERNOON/EARLY THIS
EVENING. IN ADDITION...SCATTERED THUNDERSTORMS HAVE RECENTLY
DEVELOPED OVER SOUTH CENTRAL MO THAT ARE LIFTING NORTHEASTWARD.
THESE TRENDS SUPPORT GOING FORECAST THAT PRECIPITATION CHANCES
WILL INCREASE THROUGH THE AFTERNOON. MLCAPES ARE CURRENTLY
1000-1500 J/K AND SHOULD INCREASE IN THE WARM SECTOR AS
TEMPERATURES CLIMB INTO THE LOWER-MID 80S. 0-6KM SHEAR WILL BE
RELATIVELY WEAK WHICH FAVORS MULTICELL STORMS...THOUGH INCREASING
INSTABILITY AND LARGE SCALE LIFT SUGGEST THAT THERE MAY BE A FEW
SEVERE STORMS CAPABLE OF PRODUCING SOME LARGE HAIL AND DAMAGING
WIND GUSTS THROUGH THIS EVENING. THE LOW LEVEL JET WILL REMAIN
40-50KTS TODAY...SO CANNOT RULE OUT A TORNADO OR TWO IN THE STRONGEST
STORMS. LATEST RADAR IMAGERY HAS SHOWN THE TENDENCY FOR CELLS TO
TRAIN...SO HEAVY RAINFALL DOES LOOK LIKE A REAL THREAT GIVEN PWATS
AROUND 1.8 INCHES.
BRITT
.LONG TERM...(TONIGHT THROUGH WEDNESDAY)
ISSUED AT 343 AM CDT THU MAY 30 2013
(TONIGHT THROUGH SATURDAY NIGHT)
PCPN CHANCES INCREASE TONIGHT AS NEXT IN SERIES OF MCS/S DEVELOPS OVER
WESTERN MO AND SLIDES EAST THROUGH FORECAST AREA...WITH BEST
CHANCES OF HEAVY RAIN ALONG AND NORTH OF I-70. SINCE THIS AREA HAS
HAD QUITE A BIT OF RAIN OVER THE PAST WEEK AND SOILS REMAIN
SATURATED...HAVE ISSUED A FLASH FLOOD WATCH FROM 18Z TODAY THROUGH
12Z SATURDAY. LOWS TONIGHT TO REMAIN MILD...IN THE MID 60S TO LOW
70S.
FOR FRIDAY...A LOT WILL DEPEND ON HOW SOON THIS AREA OF STORMS
WEAKENS/EXITS FORECAST AREA...ON WHAT WILL DEVELOP FOR THE AFTERNOON
AND EVENING HOURS. IF ATMOSPHERE GETS WORKED OVER...IT WILL TAKE A
LOT FOR IT TO RECOVER. FOR NOW...WILL ERR ON THE SIDE OF CAUTION
WITH STORMS REDEVELOPING BY THE AFTERNOON HOURS AS NEXT SHORTWAVE
SLIDES THROUGH. WITH DECENT INSTABILITY...MID LEVEL LAPSE RATES AND
STRENGTHENING LOW LEVEL JET...WILL SEE A CHANCE FOR SEVERE WEATHER
ONCE AGAIN FRIDAY AFTERNOON AND OVERNIGHT. ANOTHER ROUND OF HEAVY RAIN
IS POSSIBLE AS WELL...WHICH WILL EVENTUALLY SHIFT TO THE SOUTH WITH
TIME. SO MAY NEED TO EXTEND FLASH FLOOD WATCH TO INCLUDE REST OF
FORECAST AREA.
MAIN COLD FRONT TO FINALLY MOVE THROUGH THE AREA DURING THE DAY ON
SATURDAY WITH LAST IN A SERIES OF SHORTWAVES SLIDING THROUGH...SO
PCPN TO TAPER OFF BY SATURDAY EVENING.
(SUNDAY THROUGH NEXT WEDNESDAY)
COOLER AND DRIER WEATHER IS IN STORE FOR THE LAST PART OF THE
WEEKEND AND INTO EARLY NEXT WEEK. HIGHS WILL BE IN THE UPPER 60S TO
MID 70S SUNDAY THROUGH TUESDAY. THEN NEXT WEATHER SYSTEM TO APPROACH
THE REGION BY MID WEEK WITH NEXT CHANCE FOR SHOWERS AND
THUNDERSTORMS BEGINNING TUESDAY NIGHT.
BYRD
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 641 AM CDT THU MAY 30 2013
COMPLEX FORECAST FOR THIS TAF PERIOD WITH POTENTIAL FOR PROLONGED
PERIODS OF THUNDER. IN THE NEAR TERM THERE ARE TWO MAIN AREAS WITH
POTENTIAL IMPACTS. THE FIRST IS A SMALL NEWD MOVING CLUSTER OF
SHOWERS AND THUNDERSTORMS WHICH MAY IMPACT KUIN BETWEEN
1230-1400Z. THE OTHER LESS OBVIOUS IS AN AREA OF SHOWERS S/SW OF
ST LOUIS...WHICH THE MODELS INTENSIFY IN THE 13-16Z TIME FRAME AND
MOVE INTO THE ST LOUIS AREA. AFTER 16Z THE TRENDS IN SHOWERS AND
THUNDERSTORMS ARE DIFFICULT TO PINPOINT. SOMEWHERE IN THE 19-21Z
TIME FRAME SEVERAL LINES/CLUSTERS OF THUNDERSTORMS ARE EXPECTED TO
DEVELOP AND IMPACT KUIN AND KCOU THRU 01-02Z...WITH THIS ACTIVITY
SPREADING INTO THE ST LOUIS AREA BETWEEN 23-01Z. THEN DURING THE
OVERNIGHT HOURS ANOTHER CLUSTER OF THUNDERSTORMS IS EXPECTED TO
DEVELOP IN ERN KS/WRN MO AND MOVE EWD AFFECTING KCOU AROUND 10Z
AND ST LOUIS BETWEEN 12-16Z ON FRIDAY. GUSTY SOUTHERLY WINDS ARE
EXPECTED TODAY INTO EARLY EVENING.
SPECIFICS FOR KSTL...
COMPLEX FORECAST FOR THIS TAF PERIOD WITH POTENTIAL FOR PROLONGED
PERIODS OF THUNDER. AN AREA OF SHOWERS S/SW OF ST LOUIS IS
FORECAST TO INTENSIFY IN THE 13-16Z TIME FRAME AND MOVE INTO THE
ST LOUIS AREA. AFTER 16Z THE TRENDS IN SHOWERS AND THUNDERSTORMS
ARE DIFFICULT TO PINPOINT. SOMEWHERE IN THE 23-01Z TIME FRAME
SEVERAL LINES/CLUSTERS OF THUNDERSTORMS ARE EXPECTED TO DEVELOP
AND/OR MOVE INTO THE TERMINAL. THIS ACTIVITY COULD PERSIST UNTIL
05Z WITH A BREAK UNTIL ANOTHER CLUSTER OF STORMS IMPACTS KSTL BETWEEN
12-16Z ON FRIDAY. GUSTY SOUTHERLY WINDS ARE EXPECTED TODAY INTO
EARLY EVENING.
GLASS
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...FLASH FLOOD WATCH THROUGH SATURDAY MORNING FOR AUDRAIN MO-BOONE
MO-CALLAWAY MO-COLE MO-FRANKLIN MO-GASCONADE MO-JEFFERSON
MO-KNOX MO-LEWIS MO-LINCOLN MO-MARION MO-MONITEAU MO-MONROE
MO-MONTGOMERY MO-OSAGE MO-PIKE MO-RALLS MO-SHELBY MO-ST.
CHARLES MO-ST. LOUIS CITY MO-ST. LOUIS MO-WARREN MO.
IL...FLASH FLOOD WATCH THROUGH SATURDAY MORNING FOR ADAMS IL-BROWN IL-
CALHOUN IL-GREENE IL-JERSEY IL-MACOUPIN IL-MADISON IL-
MONROE IL-PIKE IL-ST. CLAIR IL.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1257 AM CDT SAT JUN 1 2013
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 319 PM CDT FRI MAY 31 2013
IN THE SYNOPTIC SCALE...THE LARGE UPPER LEVEL LOW PRESSURE SYSTEM
THAT HAS AFFECTED OUR WEATHER THE PAST FEW DAYS...CONTINUES TO SPIN
ACROSS THE DAKOTAS...WHILE RIDGING CONTINUES JUST OFF BOTH THE
WESTERN AND EASTERN COASTS. IN THE MID LEVELS...THIS SYSTEM
CONTINUES TO SURGE AN ABUNDANCE OF GULF COAST MOISTURE UP THE
MISSISSIPPI RIVER VALLEY INTO THE MIDWEST...AS SEEN IN RECENT
FLOODING ASSOCIATED WITH THUNDERSTORMS ACROSS THE COUNTRY`S
MIDSECTION. AT THE SURFACE...THE SYSTEM REMAINS NEARLY VERTICALLY
STACKED WITH LOW PRESSURE ALSO ALIGNED OVER THE DAKOTAS...AND A
SECONDARY LOW SITUATED SOUTH OF THE TROUGH AXIS ACROSS SOUTHEASTERN
KANSAS.
AS THE LOW PRESSURE SYSTEM CONTINUES TO SPIN...ALMOST NEARLY
STATIONARY...THE MAIN COLD FRONTAL BOUNDARY HAS ALREADY SHIFTED
THROUGH THE OUTLOOK AREA. HOWEVER...IT APPEARS A SECONDARY WEAK
TROUGH AXIS WILL ALSO SHIFT THROUGH THE AREA OVERNIGHT TONIGHT. WITH
THIS BOUNDARY...CONCERNS IN THE SHORT TERM WILL FOCUS MAINLY ON
PRECIPITATION CHANCES AND COOLER HIGH TEMPERATURES TOMORROW.
STARTING OFF THIS AFTERNOON...WATER VAPOR IMAGERY INDICATES THE
PRESENCE OF A WEAK SHORT WAVE TROUGH SLIDING THROUGH EASTERN
COLORADO SOUTH OF THE UPPER LEVEL LOW. AN AREA OF CUMULUS HAVE
DEVELOPED ACROSS THE AREA...AND BEGUN TO SPREAD NORTHEAST AS SEEN ON
VISIBLE SATELLITE. RADAR ALSO INDICATES AT LEAST SOME VERY LIGHT
RETURNS ACROSS NORTHWEST AND NORTH CENTRAL KANSAS. WENT AHEAD AND
PUT IN SLIGHT CHANCE POPS ACROSS NORTH CENTRAL KANSAS THROUGH THE
AFTERNOON...AS BOTH THE HRRR AND NAM MODEL SEEM TO BE HANDLING THIS
WELL. NOT EXPECTING MUCH MORE THAN A COUPLE SPRINKLES AND MAYBE A
RUMBLE OF THUNDER.
HEADING INTO THE OVERNIGHT HOURS...LATEST SATELLITE IMAGERY SHOWS
THE DEVELOPMENT OF A CUMULUS FIELD ACROSS MUCH OF NORTHWESTERN
NEBRASKA JUST BEHIND THE SECONDARY TROUGH AXIS. EXPECT THIS TROUGH
AXIS TO SLIDE THROUGH THE OUTLOOK AREA ROUGHLY AROUND 6Z...WITH WEST
WINDS SHIFTING TO THE NORTHWEST. CONTINUED SLIGHT POPS FOR THE
NORTHERN HALF OF THE OUTLOOK AREA OVERNIGHT...AS BOTH THE NAM AND
HRRR INDICATE AT LEAST SOME LIGHT SHOWERS TO PUSH THROUGH. THE UPPER
LEVEL LOW WILL FINALLY BEGIN TO SHIFT EASTWARD BY SATURDAY...THUS
DECREASING POPS FROM SOUTHWEST TO NORTHEAST THROUGHOUT THE DAY.
INSTABILITY THROUGHOUT MUCH OF THE SHORT TERM PERIOD...REMAINS
FAIRLY MINIMAL...WITH ONLY ABOUT 100 J/KG OR SO AT MOST. CONTINUED
WITH MENTION OF ONLY LIGHT RAIN SHOWERS AS A RESULT...AND LEFT OUT
MENTION OF THUNDER.
REGARDING TEMPERATURES ON SATURDAY...BEHIND THIS SECONDARY TROUGH
AXIS...COOLER AIR...WITH 850 MB TEMPERATURES ON THE ORDER OF 3 TO 4
DEGREES CELSIUS WILL SLIDE SOUTH INTO THE OUTLOOK AREA.
THUS...COMBINED WITH MODEL GUIDANCE...CONTINUED WITH TEMPERATURES IN
THE LOWER 60S ACROSS THE NORTH TO NEAR 70 IN NORTH CENTRAL KANSAS
FOR SATURDAY. SATURDAY LOOKS TO BE SHAPING INTO A FAIRLY UNPLEASANT
DAY...WITH MOSTLY CLOUDY SKIES AND COOLER TEMPERATURES. TO ADD TO
THE MIX...STRONG NORTHWEST WINDS SUSTAINED NEAR 20 KTS CAN BE
EXPECTED...AND WITH SOME MIXING WILL LEAD TO GUSTS NEAR 30 KTS.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 319 PM CDT FRI MAY 31 2013
MAIN FORECAST CONCERNS WILL BE CHANCES FOR THUNDERSTORMS AND
TEMPERATURES.
AN UPPER LEVEL SHORT WAVE RIDGE WILL MOVE ACROSS THE AREA SATURDAY
NIGHT THROUGH SUNDAY NIGHT. DURING THIS TIME DRY CONDITIONS ARE
EXPECTED. A SURFACE HIGH WILL SETTLE INTO THE AREA SATURDAY NIGHT
AND KEEP WINDS LIGHT AND TEMPERATURES WILL DROP TO THE 40S. BY
SUNDAY THE SURFACE HIGH WILL MOVE OFF TO THE EAST. WINDS WILL TURN
TO THE SOUTH AND AS THE PRESSURE GRADIENT TIGHTENS...THE WINDS WILL
INCREASE DURING THE DAY ON SUNDAY. TEMPERATURES WILL BE WARMER FOR
SUNDAY AND SUNDAY NIGHT.
FOR MONDAY THROUGH FRIDAY ANOTHER UPPER LEVEL LOW WILL WORK ITS WAY
FROM THE PACIFIC NORTHWEST...THROUGH THE NORTHERN ROCKIES AND INTO
THE NORTHERN PLAINS. THIS IS A SIMILAR TRACK TO THE ONE FROM THE
PAST WEEK. BY MONDAY THE UPPER LOW STARTS TO SEND THE FIRST SHORT
WAVE INTO THE AREA AND BRINGS A CHANCE FOR THUNDERSTORMS. MODELS
BRING SEVERAL SHORT WAVES THROUGH THE AREA DURING THE WEEK. THERE
ARE SOME MINOR TIMING DIFFERENCES BETWEEN THE MODELS. THE CHANCE
FOR THUNDERSTORMS CONTINUES DURING THE WORK WEEK AS THE UPPER LOW
CONTINUES TO SEND SHORT WAVES INTO THE AREA. IT WILL NOT BE RAINING
ALL OF THE TIME AND THERE MAY BE TIMES WHERE SOME LOCATIONS DO NOT
HAVE ANY PRECIPITATION DURING SOME PERIODS... BUT THERE IS AT LEAST
A SMALL CHANCE EVERY DAY. THE BEST CHANCES SHOULD BE DURING THE
AFTERNOON AND INTO THE OVERNIGHT HOURS.
SOME OF THE STORMS COULD BE SEVERE DURING THIS PERIOD. THE BEST
CHANCE FOR SEVERE WILL BE TUESDAY AND TUESDAY NIGHT WHEN THE MUCAPE
APPROACHES 2500 J/KG. THERE COULD BE SOME ISOLATED SEVERE AT OTHER
TIMES.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1250 AM CDT SAT JUN 1 2013
WIND WILL REMAIN GUSTY FROM THE NORTHWEST FOR MOST OF THE FORECAST
AS STRATUS MOVES IN BEHIND A COLD FRONT PASSAGE AND HEALTHY HEIGHT
RISES. EXPECT CIRRUS TO MOVE IN DURING THE EARLY MORNING SATURDAY
AND STICK AROUND FOR MOST OF THE DAY. ANY SHOWERS LATE TONIGHT
INTO SATURDAY SHOULD REMAIN MAINLY NORTH OF THE TERMINAL.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...SALTZMAN
LONG TERM...JCB
AVIATION...HEINLEIN
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
303 AM EDT SAT JUN 1 2013
.SYNOPSIS...
VERY WARM WEATHER WILL CONTINUE THROUGH THE WEEKEND. MUCH OF THE
TIME SHOULD BE RAIN-FREE THROUGH SATURDAY...WITH JUST SOME HIT AND
MISS SHOWERS AND THUNDERSTORMS POSSIBLE SATURDAY AFTERNOON AND
EVENING. A BETTER CHANCE FOR SHOWERS AND STORMS WILL EXIST
SUNDAY...AS A COLD FRONT NEARS THE REGION FROM THE WEST. MUCH
COOLER TEMPERATURES WILL FOLLOW THIS FRONT EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
820 PM UPDATE...
THUNDERSTORM ACTIVITY CONTINUES ALONG LAKE ERIE UNDER THE
INFLUENCE OF A NORTHWARD MOVING WAVE. THE LATEST HRRR FORECASTS
SOME OF THE SWRN NY ACTIVITY TO BRUSH AGAINST OUR WESTERN FA
BORDERS BETWEEN 7Z-9Z. HAVE ADDED ISOLATED CONVECTION TO THE
WESTERN GRIDS FOR EARLY SATURDAY MORNING.
420 PM UPDATE... ISOLD TSRA HAVE FIRED OVER OUR SERN ZNS LATE THIS
AFTN...IN RESPONSE TO A PASSING UPR-LVL WAVE. THIS ACTIVITY SHOULD
QUICKLY DIE OUT EARLY THIS EVE...AS FORCING WANES...AND THE AMS
STABILIZES DIURNALLY.
LTR TNT/TWDS DAYBREAK...THE REMNANTS OF CONVECTIVE ACTIVITY WELL
TO OUR W ATTM ACRS SRN ONT/LK ERIE COULD APPROACH OUR FAR NRN/WRN
ZNS. IN GENERAL...THIS PCPN SHOULD BE IN A WEAKENED PHASE BY THAT
TIME...AS IT WILL HAVE WELL OUTRUN ITS MAIN UPR-LVL SUPPORT. WE
HAVE ISOLD-SCTD POPS ACRS THE FINGER LKS/MOHAWK VLY/SRN TUG HILL
ZNS TO COVER THIS POTENTIAL.
DRY WX FORESEEN FROM THE TWIN TIERS SWD OVERNIGHT...WITH VERY
PATCHY FOG/HZ PSBL.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH MONDAY/...
430 PM UPDATE... ALTHOUGH WE`LL REMAIN UNDER A SYNOPTIC-SCALE UPR
RIDGE SAT...WE MAY SEE SOME HGT FALLS AFTER 18Z...SPCLY NRN/WRN
AREAS. THIS...COMBINED WITH A FAST MOVG UPR IMPULSE BRUSHING
UPSTATE NY...COULD SPARK SOME DIURNALLY ENHANCED SHRA/TSRA. THE
BEST CHC (SCTD VERBIAGE) SHOULD BE IN OUR NRN/WRN ZNS...WITH MORE
ISOLD COVERAGE ELSEWHERE.
SAT NGT...REMNANT CONVECTION FROM THE DAYTIME HRS SHOULD WANE DURG
THE EVE...LEADING TO A RELATIVE LULL FOR MOST OF THE NGT. TWDS SUN
AM...AS A MUCH BETTER DEFINED UPR-LVL TROUGH SWINGS TWDS SRN
ONT/LK ONT...WE COULD SEE A RENEWED AREA OF SHRA/TSRA. THUS...WE
INCREASE POPS INTO THE LIKELY/NUM RANGES BY THIS TIME...AGN MAINLY
NRN/WRN PTNS OF THE FA.
SUN SEEMS A BIT COMPLICATED FROM THIS EARLY VANTAGE PT...AS ONE
WELL DEFINED UPR WV (JUST ALLUDED TO) SHOULD SWING BY TO OUR N
DURG THE AM/MIDDAY HRS...WITH PERHAPS A DECREASE IN MID TO UPR-LVL
FORCING FOR CNY/NE PA THEREAFTER. THE NAM SEEMS MOST BULLISH ON
THIS SCENARIO...SHOWING A DVLPG MID-LVL CAP SUN AFTN/EVE...LIKELY
DUE TO DVM/COMPRESSIONAL WARMING AT THAT LVL BEHIND THE WV...AND
WITH DETERIORATING UPR JET DYNAMICS. THE GFS...HOWEVER...IS A BIT
SLOWER WITH THE UPR WV...AND ALSO SHOWS A BETTER DEFINED PV TAIL
TO THE S THROUGH OUR FA SUN AFTN...JUST IN ADVANCE OF THE SFC
FRNT. SFC COLD FRNTL TIMING SEEMS OPTIMAL FOR TSRA DVLPMT...WITH
FROPA EXPECTED EARLY IN THE EVE...HOWEVER MID TO UPR-LVL FORCING SEEMS
LIKE THE MOST QUESTIONABLE ASPECT. FOR NOW...WE FELT IT WAS PRUDENT TO
CONTINUE TO MENTION PSBL SVR TSRA/HVY RAINFALL ON SUN...WITH MODEL
DIFFS EVIDENT...AND SMALLER-SCALE DETAILS (NOT TYPICALLY WELL
RESOLVED THIS FAR OUT) LIKELY TO MAKE A BIG DIFFERENCE IN HOW
THINGS TRANSPIRE ON SUN. AT ANY RATE...WE FELT COMFORTABLE
CONTINUING LIKELY/NUM POPS SUN AFTN INTO THE EVE PD.
THE COLD FRNT SHOULD SLOWLY MAKE ITS WAY THROUGH THE RGN BY LTR
SUN NGT...WITH COOLER TEMPS TO FOLLOW ON MON.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
3 AM UPDATE...LATEST MODEL RUNS ARE VERY CONSISTENT WITH PREVIOUS
CYCLE, JUST MINOR TWEAKS OF TEMPS/POPS.
330 PM UPDATE...
A COOLER BUT VERY QUIET LONG TERM FORECAST EXPECTED WITH THE NEXT
SHOT AT RAIN HOLDING OFF UNTIL THE END OF NEXT WEEK. WE HAVE A
DECENT SHORT WAVE MOVING THROUGH AROUND 12Z TUESDAY...BUT THE BEST
MOISTURE AND LIFT REMAIN WELL TO OUR NORTH NEAR A CLOSED LOW OVER
EASTERN QUEBEC. A SLIGHT INCREASE IN CLOUD COVER IS POSSIBLE OVER
THE FAR NORTH BUT WILL CONTINUE A DRY FORECAST. AFTER THAT TIME
HEIGHTS BUILD WITH AN H5 RIDGE CRESTING OVERHEAD BY WEDNESDAY
NIGHT. TEMPS WILL MODERATE DURING THIS TIME WITH DRY WEATHER
THROUGH MOST OF THE AREA THURSDAY. BY THURSDAY NIGHT INTO FRIDAY
AS OUR FLOW TURNS MORE INTO THE SOUTHWEST...BOTH THE EURO AND GFS
SHOW A FRONTAL BOUNDARY MOVING TOWARD OUR AREA. THE EURO WOULD
KEEP IT WEST OF US THROUGH THE PERIOD WHILE THE GFS INTRODUCES
PRECIP MAINLY OVER THE WESTERN HALF OF THE CWA. CHANCE POPS FROM
WPC GUIDANCE LOOK GOOD THIS FAR OUT AND WILL FOLLOW.
&&
.AVIATION /07Z SATURDAY THROUGH WEDNESDAY/...
OVERALL, VFR CONDITIONS WILL CONTINUE THROUGH THIS TAF PERIOD.
CONVECTION EARLY THIS MORNING OVER WESTERN NY AND SOUTHERN ONTARIO WILL
CONTINUE TO WEAKEN AND LIFT NORTHEAST THIS MORNING REMAINING AWAY
FROM THE TERMINALS. ONLY CONVECTIVE DEBRIS WILL RESULT FROM THIS
WITH SCATTERED MID LAYER CLOUDS AND SCT/BKN CI. AT KELM, VALLEY
FOG IS EXPECTED TO FORM WITH IFR VSBYS POSSIBLE BETWEEN 08Z-11Z.
FOR TODAY, MARGINAL INSTABILITY ALONG WITH EMBEDDED SHORT WAVES
IN SOUTHWEST FLOW MAY TRIGGER SCATTERED THUNDERSTORMS THIS
AFTERNOON. INCLUDED PROB30 18Z-22Z IN ALL TAFS FOR MVFR
THUNDERSTORMS.
LIGHT WINDS BECOMING SOUTHWEST AT 10 KNOTS WITH GUSTS 15-18 KNOTS
DECREASING THIS EVENING.
OUTLOOK...
SUN...POTENTIAL FOR MVFR IN SHRA/TSRA.
MON/TUE...VFR EXCEPT POSSIBLE LINGERING MVFR FROM -SHRA EARLY MON.
WED...VFR.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...MLJ
NEAR TERM...DJP/MLJ
SHORT TERM...MLJ
LONG TERM...HEDEN/RRM
AVIATION...RRM
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
124 AM EDT SAT JUN 1 2013
.SYNOPSIS...
VERY WARM WEATHER WILL CONTINUE THROUGH THE WEEKEND. MUCH OF THE
TIME SHOULD BE RAIN-FREE THROUGH SATURDAY...WITH JUST SOME HIT AND
MISS SHOWERS AND THUNDERSTORMS POSSIBLE SATURDAY AFTERNOON AND
EVENING. A BETTER CHANCE FOR SHOWERS AND STORMS WILL EXIST
SUNDAY...AS A COLD FRONT NEARS THE REGION FROM THE WEST. MUCH
COOLER TEMPERATURES WILL FOLLOW THIS FRONT EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
820 PM UPDATE...
THUNDERSTORM ACTIVITY CONTINUES ALONG LAKE ERIE UNDER THE
INFLUENCE OF A NORTHWARD MOVING WAVE. THE LATEST HRRR FORECASTS
SOME OF THE SWRN NY ACTIVITY TO BRUSH AGAINST OUR WESTERN FA
BORDERS BETWEEN 7Z-9Z. HAVE ADDED ISOLATED CONVECTION TO THE
WESTERN GRIDS FOR EARLY SATURDAY MORNING.
420 PM UPDATE... ISOLD TSRA HAVE FIRED OVER OUR SERN ZNS LATE THIS
AFTN...IN RESPONSE TO A PASSING UPR-LVL WAVE. THIS ACTIVITY SHOULD
QUICKLY DIE OUT EARLY THIS EVE...AS FORCING WANES...AND THE AMS
STABILIZES DIURNALLY.
LTR TNT/TWDS DAYBREAK...THE REMNANTS OF CONVECTIVE ACTIVITY WELL
TO OUR W ATTM ACRS SRN ONT/LK ERIE COULD APPROACH OUR FAR NRN/WRN
ZNS. IN GENERAL...THIS PCPN SHOULD BE IN A WEAKENED PHASE BY THAT
TIME...AS IT WILL HAVE WELL OUTRUN ITS MAIN UPR-LVL SUPPORT. WE
HAVE ISOLD-SCTD POPS ACRS THE FINGER LKS/MOHAWK VLY/SRN TUG HILL
ZNS TO COVER THIS POTENTIAL.
DRY WX FORESEEN FROM THE TWIN TIERS SWD OVERNIGHT...WITH VERY
PATCHY FOG/HZ PSBL.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH MONDAY/...
430 PM UPDATE... ALTHOUGH WE`LL REMAIN UNDER A SYNOPTIC-SCALE UPR
RIDGE SAT...WE MAY SEE SOME HGT FALLS AFTER 18Z...SPCLY NRN/WRN
AREAS. THIS...COMBINED WITH A FAST MOVG UPR IMPULSE BRUSHING
UPSTATE NY...COULD SPARK SOME DIURNALLY ENHANCED SHRA/TSRA. THE
BEST CHC (SCTD VERBIAGE) SHOULD BE IN OUR NRN/WRN ZNS...WITH MORE
ISOLD COVERAGE ELSEWHERE.
SAT NGT...REMNANT CONVECTION FROM THE DAYTIME HRS SHOULD WANE DURG
THE EVE...LEADING TO A RELATIVE LULL FOR MOST OF THE NGT. TWDS SUN
AM...AS A MUCH BETTER DEFINED UPR-LVL TROUGH SWINGS TWDS SRN
ONT/LK ONT...WE COULD SEE A RENEWED AREA OF SHRA/TSRA. THUS...WE
INCREASE POPS INTO THE LIKELY/NUM RANGES BY THIS TIME...AGN MAINLY
NRN/WRN PTNS OF THE FA.
SUN SEEMS A BIT COMPLICATED FROM THIS EARLY VANTAGE PT...AS ONE
WELL DEFINED UPR WV (JUST ALLUDED TO) SHOULD SWING BY TO OUR N
DURG THE AM/MIDDAY HRS...WITH PERHAPS A DECREASE IN MID TO UPR-LVL
FORCING FOR CNY/NE PA THEREAFTER. THE NAM SEEMS MOST BULLISH ON
THIS SCENARIO...SHOWING A DVLPG MID-LVL CAP SUN AFTN/EVE...LIKELY
DUE TO DVM/COMPRESSIONAL WARMING AT THAT LVL BEHIND THE WV...AND
WITH DETERIORATING UPR JET DYNAMICS. THE GFS...HOWEVER...IS A BIT
SLOWER WITH THE UPR WV...AND ALSO SHOWS A BETTER DEFINED PV TAIL
TO THE S THROUGH OUR FA SUN AFTN...JUST IN ADVANCE OF THE SFC
FRNT. SFC COLD FRNTL TIMING SEEMS OPTIMAL FOR TSRA DVLPMT...WITH
FROPA EXPECTED EARLY IN THE EVE...HOWEVER MID TO UPR-LVL FORCING SEEMS
LIKE THE MOST QUESTIONABLE ASPECT. FOR NOW...WE FELT IT WAS PRUDENT TO
CONTINUE TO MENTION PSBL SVR TSRA/HVY RAINFALL ON SUN...WITH MODEL
DIFFS EVIDENT...AND SMALLER-SCALE DETAILS (NOT TYPICALLY WELL
RESOLVED THIS FAR OUT) LIKELY TO MAKE A BIG DIFFERENCE IN HOW
THINGS TRANSPIRE ON SUN. AT ANY RATE...WE FELT COMFORTABLE
CONTINUING LIKELY/NUM POPS SUN AFTN INTO THE EVE PD.
THE COLD FRNT SHOULD SLOWLY MAKE ITS WAY THROUGH THE RGN BY LTR
SUN NGT...WITH COOLER TEMPS TO FOLLOW ON MON.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
330 PM UPDATE...
A COOLER BUT VERY QUIET LONG TERM FORECAST EXPECTED WITH THE NEXT
SHOT AT RAIN HOLDING OFF UNTIL THE END OF NEXT WEEK. WE HAVE A
DECENT SHORT WAVE MOVING THROUGH AROUND 12Z TUESDAY...BUT THE BEST
MOISTURE AND LIFT REMAIN WELL TO OUR NORTH NEAR A CLOSED LOW OVER
EASTERN QUEBEC. A SLIGHT INCREASE IN CLOUD COVER IS POSSIBLE OVER
THE FAR NORTH BUT WILL CONTINUE A DRY FORECAST. AFTER THAT TIME
HEIGHTS BUILD WITH AN H5 RIDGE CRESTING OVERHEAD BY WEDNESDAY
NIGHT. TEMPS WILL MODERATE DURING THIS TIME WITH DRY WEATHER
THROUGH MOST OF THE AREA THURSDAY. BY THURSDAY NIGHT INTO FRIDAY
AS OUR FLOW TURNS MORE INTO THE SOUTHWEST...BOTH THE EURO AND GFS
SHOW A FRONTAL BOUNDARY MOVING TOWARD OUR AREA. THE EURO WOULD
KEEP IT WEST OF US THROUGH THE PERIOD WHILE THE GFS INTRODUCES
PRECIP MAINLY OVER THE WESTERN HALF OF THE CWA. CHANCE POPS FROM
WPC GUIDANCE LOOK GOOD THIS FAR OUT AND WILL FOLLOW.
&&
.AVIATION /05Z SATURDAY THROUGH WEDNESDAY/...
OVERALL, VFR CONDITIONS WILL CONTINUE THROUGH THIS TAF PERIOD.
CONVECTION EARLY THIS MORNING OVER WESTERN NY AND SOUTHERN ONTARIO WILL
CONTINUE TO WEAKEN AND LIFT NORTHEAST THIS MORNING REMAINING AWAY
FROM THE TERMINALS. ONLY CONVECTIVE DEBRIS WILL RESULT FROM THIS
WITH SCATTERED MID LAYER CLOUDS AND SCT/BKN CI. AT KELM, VALLEY
FOG IS EXPECTED TO FORM WITH IFR VSBYS POSSIBLE BETWEEN 08Z-11Z.
FOR TODAY, MARGINAL INSTABILITY ALONG WITH EMBEDDED SHORT WAVES
IN SOUTHWEST FLOW MAY TRIGGER SCATTERED THUNDERSTORMS THIS
AFTERNOON. INCLUDED PROB30 18Z-22Z IN ALL TAFS FOR MVFR
THUNDERSTORMS.
LIGHT WINDS BECOMING SOUTHWEST AT 10 KNOTS WITH GUSTS 15-18 KNOTS
DECREASING THIS EVENING.
OUTLOOK...
SUN...POTENTIAL FOR MVFR IN SHRA/TSRA.
MON/TUE...VFR EXCEPT POSSIBLE LINGERING MVFR FROM -SHRA EARLY MON.
WED...VFR.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...MLJ
NEAR TERM...DJP/MLJ
SHORT TERM...MLJ
LONG TERM...HEDEN
AVIATION...RRM
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
337 AM EDT SAT JUN 1 2013
.SYNOPSIS...
OCCASIONAL THUNDERSTORMS WILL CONTINUE TODAY INTO TONIGHT AHEAD
OF AN APPROACHING COLD FRONT. HIGH PRESSURE WILL SETTLE INTO THE
AREA FOR THE FIRST PART OF THE UPCOMING WEEK...USHERING IN A DRIER
AND COOLER AIRMASS.
&&
.NEAR TERM /THROUGH TODAY/...
LINE OF CONVECTION EXTENDING FROM SOUTHERN ILLINOIS UP INTO
NORTHEAST INDIANA HAS BEEN PUSHING VERY SLOWLY EAST THROUGH THE
EARLY MORNING HOURS. THE AIRMASS JUST OUT AHEAD OF IT REMAINS AT
LEAST MARGINALLY UNSTABLE...BUT THE INSTABILITY DOES DROP OFF
FARTHER EAST ACROSS OHIO. THE ORIENTATION OF THE 20-30 KNOT 0-3 KM
SHEAR VECTORS WOULD SUGGEST THAT THIS LINE WILL MAINTAIN ITSELF
OVER THE NEXT SEVERAL HOURS AS IT PROGRESSES EAST...BUT AS IT
BEGINS TO ENCOUNTER THE MORE STABLE AIRMASS...EXPECT TO SEE SOME
WEAKENING IN THE STORM STRENGTH. AS A RESULT...THINK SHOWERS AND
THUNDERSTORMS WILL MAKE IT INTO AT LEAST OUR WESTERN AREAS LATER
THIS MORNING...BUT THINK SEVERE THREAT IS FAIRLY LOW.
QUITE A BIT OF UNCERTAINTY EXISTS FOR HOW THINGS WILL PLAY OUT
THROUGH THE REMAINDER OF THE DAY. AS PCPN WORKS EAST...DEBRIS
CLOUDS SHOULD OVERSPREAD OUR FA THROUGH THE REST OF THE MORNING.
THIS WILL PLAY A ROLE IN HOW FAST WE ARE ABLE TO RECOVER THROUGH
THIS AFTERNOON AND DESTABILIZE. BOTH THE 00Z NAM AND 00Z GFS ARE
SUGGESTING ML CAPES IN THE 500-1000 J/KG RANGE LATER TODAY...WITH
THE HIGHEST VALUES ACROSS THE SOUTH. MEANWHILE...THE RAP IS
CONSIDERABLY MORE UNSTABLE...BUT LIKELY OVERDONE WITH SURFACE
DEWPOINTS IN THE LOW 70S.
INCREASING MID LEVEL FLOW THROUGH THE DAY WILL COUPLE WITH A
PERSISTENT 20-30 KNOT 850 MB JET TO PRODUCE INCREASING LOW AND DEEP
LAYER SHEAR AS WE PROGRESS THROUGH THE DAY. THIS MAY BE ENOUGH TO
OVERCOME SOME OF THE POSSIBLE LACK OF INSTABILITY TO STILL RESULT
IN SOME ORGANIZED CONVECTION. WITH CONTINUED GOOD MOISTURE
TRANSPORT UP INTO OUR AREA AND PWS AROUND 150 PERCENT OF
NORMAL...LOCALLY HEAVY RAIN IS LIKELY WITH ANY OF THE STORMS.
CONSIDERED A FLASH FLOOD WATCH FOR AT LEAST THE NORTHWEST HALF OF
OUR AREA...BUT CONFIDENCE IS JUST TOO LOW ON BOTH THE DEGREE OF
DEVELOPMENT AND THE PLACEMENT.
EXPECT HIGHS RANGING FROM THE UPPER 70S NORTHWEST TO MID 80S
SOUTHEAST...BUT THESE TOO WILL BE DEPENDENT ON THE AMOUNT OF
DEBRIS CLOUDS.
&&
.SHORT TERM /TONIGHT THROUGH MONDAY/...
THE BEST SEVERE THREAT WILL LIKELY BE THIS EVENING AS SHOWERS AND
THUNDERSTORMS BECOME MORE WIDESPREAD AHEAD OF THE APPROACHING COLD
FRONT. THIS WILL COINCIDE WITH THE HIGHEST 0-1KM BULK SHEAR AS IT
PUSHES UP INTO THE 25-30 KNOT RANGE AND BETTER DEEP LAYER SHEAR
DROPS DOWN FROM THE NORTHWEST. WOULD EXPECT DAMAGING WIND TO BE
THE PRIMARY THREAT...BUT GIVEN THE AMOUNT OF LOW LEVEL SHEAR...AN
ISOLATED TORNADO WILL ALSO BE POSSIBLE.
THUNDERSTORMS WILL TAPER OFF TO SHOWERS FROM THE NORTHWEST
OVERNIGHT AS WE GET ON THE BACKSIDE OF THE FRONT AND START TO LOSE
OUR INSTABILITY. SHOWERS AND PERHAPS A FEW THUNDERSTORMS MAY LINGER
INTO SUNDAY ACROSS OUR SOUTHEAST...WITH A FEW SPOTTY SHOWERS
ELSEWHERE AS THE MID LEVEL TROUGH AXIS PIVOTS ACROSS OUR AREA.
COOLER AIR MOVING IN BEHIND THE FRONT WILL KEEP HIGHS IN THE 70S
FOR SUNDAY. HIGH PRESSURE AND A DRIER/COOLER AIRMASS WILL THEN
SETTLE INTO THE AREA FOR MONDAY. EXPECT HIGHS ON MONDAY ONLY IN
THE UPPER 60S TO LOWER 70S.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
DETERMINISTIC MODELS ARE IN FAIRLY GOOD AGREEMENT THROUGH ABOUT MID
WEEK...THEN THEY START TO DIVERGE ON THE NEXT UPR LVL LOW IN TERMS
OF STRENGTH AND SPEED TOWARD THE END OF THE WEEK. HAVE USED A BLEND
OF MODEL RUNS THROUGH WEDNESDAY...THEN SIDED WITH THE 31.12Z ECMWF
AND HPC THEREAFTER.
FOR MONDAY NIGHT INTO TUESDAY...CANADIAN HIGH PRESSURE WILL
SETTLE INTO THE GREAT LAKES AND OHIO VALLEY. MOSTLY CLEAR SKIES
WILL BE FOLLOWED BY MOSTLY SUNNY CONDITIONS ON TUESDAY. COOL
OVERNIGHT LOWS WILL RESULT ONCE AGAIN IN BELOW NORMAL HIGHS ON
TUESDAY IN THE UPPER 60S TO THE LOWER 70S.
FOR WEDNESDAY INTO THURSDAY...SURFACE HIGH PRESSURE IS FORECAST TO
SLIDE EAST AS A WEAK MID LVL RIDGE MOVES ACROSS THE GREAT LAKES.
SKIES WILL BECOME PARTLY CLOUDY WITH A MODIFICATION IN THE AIRMASS.
FOR THURSDAY NIGHT INTO FRIDAY...UPR LVL LOW WILL SLOWLY MOVE FROM
THE NRN PLAINS INTO THE WRN GREAT LAKES. MOISTURE FUNNELING
NORTHWARD AHEAD OF A WEAK FRONTAL BOUNDARY WILL RESULT IN A THREAT
FOR SHOWERS AND THUNDERSTORMS. HAVE KEPT POPS IN THE CHANCE CATEGORY
AT THIS TIME DUE TO WEAK FEATURES. TEMPERATURES WILL BE NEAR
SEASONAL NORMALS BY THE END OF THE WEEK.
&&
.AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
TIMING DIFFICULT WITH CONVECTIVE COMPLEX PUSHING THROUGH INDIANA
WITH SLOW PROGRESSION LIKELY NOT TO YIELD TSRA UNTIL NEAR 10Z AT
KDAY/11Z KCVG AND KLUK. STORMS HAVE HISTORY OF VERY HEAVY
RAIN. SO WITH PRECIPITATION ONSET...HAVE INCLUDED A TEMPO GROUP OF
MVFR CIGS AND VSBYS WITH PRECIP TIMING. AFTER ABOUT 14Z WEST AND
16Z EAST...SHRA/TSRA ACTIVITY WILL BECOME MORE SCATTERED UNTIL THE
MAIN ACTIVITY WITH THE PREFRONTAL STORMS APPROACHES. MVFR
CIGS/VSBYS POSSIBLE...WITH EVEN IFR IN HEAVY RAIN POTENTIAL.
OUTLOOK...THUNDERSTORMS POSSIBLE THROUGH EARLY SUNDAY.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...JGL
NEAR TERM...JGL
SHORT TERM...JGL
LONG TERM...HICKMAN
AVIATION...JDR
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
201 AM EDT SAT JUN 1 2013
.SYNOPSIS...
WARM SECTOR THROUGH SATURDAY NIGHT WITH CONVECTION POSSIBLE
ESPECIALLY DURING DAYTIME HEATING HOURS. COLD FRONT CROSSES
SUNDAY. COOLER AND DRIER TO START NEXT WEEK.
&&
.NEAR TERM /THROUGH TODAY/...
1030 PM UPDATE...
NO CHANGES NEEDED AS CONVECTION OVER THE MIDDLE OHIO VALLEY WINDS
DOWN FOR THIS NT.
PREV DISCN...
18Z RADAR IMAGERY SHOWING SHOWERS AND THUNDERSTORMS CONTINUING TO
DEVELOP TO THE WEST ROUGHLY AROUND THE IN/OH BORDER AREA SOUTHWARD
INTO CENTRAL KENTUCKY. OUT AHEAD OF THAT GENERAL AREA A FEW DISCRETE
THUNDERSTORMS HAD FORMED TO THE EAST. PRIMARY CONCERNS IN THE NEAR
TERM REVOLVE AROUND THIS EVENING/S CONVECTION AS WELL AS
REDEVELOPING SHOWERS/THUNDERSTORMS TOMORROW.
THIS EVENING...TOUGH CALL ON EXACTLY HOW FAR EAST TO TAKE PRECIP
WITH A READILY-APPARENT DECAYING MCV PUSHING E/NE-WARD ACROSS NORTH
CENTRAL KY. LATEST RAP SEEMS TO HAVE SOMEWHAT OF A HANDLE ON THE
SHEAR ASSOC WITH IT...WITH NEAR 40KTS OF SHEAR DEPICTED ACROSS THE
SW OHIO AND NC KY AREAS. FURTHER EAST OVER OUR WESTERN ZONES...SHEAR
IS APPRECIABLY LOWER AND ONLY AROUND 15-20KTS. LATEST RAP RUNS ALSO
CONTINUE TO WEAKEN/SHEAR THE VORT MAX ASSOC WITH THE MCV...WITH
SHEAR VALUES ONLY CLIMBING TO AROUND 25KTS NEAR PERRY CO OH...AND
LESS POINTS EAST AND SOUTH OF THAT...BY 00Z. INSTABILITY WILL BE
DECREASING AS WELL AND BECOMING MORE ELEVATED AS USUAL...WHICH
SHOULD SPELL A DECREASING RISK OF STRONG WINDS. ALL IN ALL...DO
BELIEVE SHOWERS AND SOME THUNDERSTORMS STAND A DECENT CHANCE OF
REACHING OUR WESTERN ZONES AND PARTICULARLY THE SE OHIO ZONES. WHILE
A SEVERE THUNDERSTORM CAN/T BE COMPLETELY RULED OUT IN THOSE
LOCATIONS...CURRENT THINKING IS THAT THE BULK OF ANY SEVERE WX
REMAINS WEST.
OVERNIGHT...WILL KEEP GENERAL INHERITED FORECAST AND DRY OUT MOST
LOCATIONS BTWN 03Z-06Z. DID ELECT TO KEEP A SLIGHT CHANCE ACROSS THE
FAR NW ZONES HOWEVER...ON THE NOSE OF A 850MB JET. PREV FCST LOW
TEMPS IN THE MID/UPPER 60S LOWLANDS STILL LOOK GOOD. SLIGHTLY
STRONGER BL WINDS OVERNIGHT PROGGED AFTER 06Z SHOULD PRECLUDE
WIDESPREAD FOG FORMATION BUT THE USUAL SPOTS SUCH AS EKN WILL MOST
LIKELY SEE REDUCED VIS NEAR DAWN.
TOMORROW...INHERITED MAX TEMPS IN THE MID/UPPER 80S LOWLANDS LOOK
GOOD. PRIMARY FOCUS ON THUNDERSTORMS AND SVR THUNDERSTORM POTENTIAL.
NOT REALLY SEEING MUCH IN THE WAY OF ANY ORGANIZED LARGE-SCALE LIFT
FOR MUCH OF THE DAY WITH THE TROUGH AXIS AND SFC COLD FRONT STILL
WELL TO THE WEST. LOWERED POPS TO LOW CHANCE FOR THE MORNING HOURS
AND INTO THE EARLY AFTERNOON HOURS AS SUCH. BTWN 18Z-21Z...GOOD
DYNAMICS ARRIVE TO THE WEST OF OUR AREA...OVER IN/WEST OH SOUTHWARD
INTO CENTRAL KY. THIS AREA SHOULD SERVE FOR ORGANIZED CONVECTIVE
INITIATION BY 21Z...WITH SUPERCELLS A POSSIBILITY. THIS AREA WILL
SLOWLY PROGRESS EASTWARD...BUT RIGHT-MOVER MOTION WOULD TAKE THESE
STORMS IN AN MORE E/NE DIRECTION AROUND 30KTS. AGAIN AS WITH THIS
AFTERNOON...THE BULK OF SVR WX SHOULD REMAIN WEST BUT WITH BETTER
SHEAR OVER OUR AREA TOMORROW A BETTER LIKELIHOOD OF SVR WX OVER OUR
WESTERN ZONES EXISTS PRIMARILY LATE AFTERNOON INTO MID-EVE HOURS.
&&
.SHORT TERM /TONIGHT THROUGH MONDAY NIGHT/...
COLD FRONT WILL PUSH EAST INTO THE CWA SUNDAY MORNING. TIMING OF THE
FRONT LOOKS TO BE A FEW HOURS SLOWER THAN PREVIOUS RUNS...BUT STILL
THINKING MUCH OF THE CWA WILL NOT SEE MUCH IN TERMS OF SEVERE DUE TO
TIMING...ALTHOUGH THE EASTERN ZONES WILL BE MORE SUSCEPTIBLE DUE TO
LATER FRONTAL PASSAGE. DECENT CAPE...GENERALLY 1500-2000
J/KG...ALONG WITH 30-40 KTS 0-6KM BULK SHEAR WILL CREATE A POTENTIAL
FOR STRONG STORMS...WITH WINDS...AND HAIL THE PRIMARY
THREATS...MAINLY ACROSS THE EAST. HOWEVER...PLENTY OF CLOUD COVER
OUT AHEAD OF THE FRONT MAY ALSO HELP TO MITIGATE THE SEVERE
THREAT...ESPECIALLY EARLY ON. SO FOR NOW...ITS A WAIT AND SEE
SCENARIO TO SEE IF ANY OF THE ABOVE MENTIONED FACTORS ARE ABLE TO
LINE UP...BUT LOOKING LIKE BULK OF SEVERE THREAT WILL BE TO THE EAST
OF THE CWA. AS OF RIGHT NOW...SPC HAS THE SLIGHT RISK TO THE EAST OF
THE CWA...WITH CWA IN GENERAL THUNDER...AND A 5 PERCENT PROB OUTLOOK
FOR SEVERE.
COLD FRONT WILL EXIT TO THE EAST OF THE CWA SUNDAY NIGHT...WITH
COOLER AND DRIER WEATHER TAKING HOLD.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
GENERALLY FOLLOWED WPC THINKING WITH SOME TWEAKS.
HIGH PRESSURE WILL DOMINATE THE REGION ON TUESDAY...WITH
TEMPERATURES NEAR NORMAL READINGS. HOWEVER...THE HIGH WILL PUSH
EAST ON WEDNESDAY...RESULTING IN SOUTHERLY WINDS AND WARMER
TEMPERATURES. THE SOUTHERLY WINDS WILL ALSO RESULT IN INCREASING
LOW-LEVEL MOISTURE AND THE CHANCES FOR SHOWERS AND STORMS...MAINLY
DIURNAL IN NATURE...WILL ALSO RETURN THROUGH THE REMAINDER OF THE
PERIOD.
&&
.AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
06Z SATURDAY THRU 06Z SUNDAY...
THRU 12Z SATURDAY...SCATTERED NOCTURNAL SHOWERS AND POSSIBLY AN
EMBEDDED THUNDERSTORM ACROSS NORTHWEST HALF OF THE AREA FOR THE
REMAINDER OF THE OVERNIGHT HOURS. OTHERWISE...GENERAL VFR WITH
WIDESPREAD ALTOCU. DEPENDING ON CLOUD COVER...LOCALLY IFR FOG
POSSIBLE SHELTERED MOUNTAIN VALLEYS INCLUDING EKN.
AFTER 12Z...VFR DAY EXPECTED...WITH MORNING ALTOCU AND THEN
MIDDAY AND AFTERNOON HIGH BASED CU. WIDELY SCATTERED SHOWERS AND
THUNDERSTORMS WILL FORM IN THE AFTERNOON HEATING BUT WITH MOST AREAS
REMAINING DRY. THERE IS A SLIGHT RISK FOR SEVERE THUNDERSTORMS WEST
OF THE OHIO RIVER LATER THIS AFTERNOON.
AFTER 00Z...BAND OF CONVECTION WELL AHEAD OF A COLD FRONT WILL
SLOWLY MOVE EASTWARD AND REACH THE OHIO RIVER BY 06Z SUNDAY.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 06Z SUNDAY...
FORECAST CONFIDENCE...MEDIUM.
ALTERNATE SCENARIOS: TIMING OF BAND OF CONVECTION LATER PART OF
PERIOD MAY VARY.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
DATE SAT 06/01/13
UTC 1HRLY 06 07 08 09 10 11 12 13 14 15 16 17
EDT 1HRLY 02 03 04 05 06 07 08 09 10 11 12 13
CRW CONSISTENCY H M M M H H H H H H H H
HTS CONSISTENCY H H H H H H H H H H H H
BKW CONSISTENCY H H H H H H H H H H H H
EKN CONSISTENCY L L L L L M M H H H H H
PKB CONSISTENCY H H H H H H H H H H H H
CKB CONSISTENCY M M M M H H H H H H H H
AFTER 06Z SUNDAY...
IFR POSSIBLE IN SHOWERS AND THUNDERSTORMS SUNDAY INTO SUNDAY
NIGHT...AND IN POST-RAIN FOG AND LOW CLOUDS LATE SUNDAY NIGHT INTO
MONDAY MORNING.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...JSH/50/SL
NEAR TERM...TRM/50
SHORT TERM...SL
LONG TERM...JSH
AVIATION...JMV
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
1152 PM CDT FRI MAY 31 2013
.UPDATE...FOR 06Z AVIATION.
&&
.AVIATION...06Z TAF DISCUSSION.
CONTINUING TO MONITOR THE PROGRESSION OF THE LARGE LINE OF TS BACK
OVER MISSOURI AT ISSUANCE. SOME GUIDANCE IS SUGGESTING IT WILL
MAKE IT INTO MIDDLE TENNESSEE BY DAYBREAK...THOUGH IT WILL BE A
PITTANCE OF ITS CURRENT STATE. WILL PREVAIL RA AND VCTS STARTING
AT 12Z FOR KCKV...AND THIS PARTICULAR FEATURE SHOULD DISSIPATE
BEFORE REACHING KBNA. THE REST OF THE TAF CYCLE REVOLVES AROUND
THE APPROACHING FRONTAL SYSTEM DUE INTO THE AREA TOMORROW EVENING.
FROPA SHOULD HAPPEN TOWARDS THE END OF THIS CYCLE WITH ASSOCIATED
SHOWERS AND TS...SCATTERED DURING THE AFTERNOON...THEN MORE
WIDESPREAD AFTER 02Z. WILL HOLD ONTO VFR FLIGHT CONDITIONS THROUGH
THE EVENT AS GUIDANCE IS PRETTY CONSISTENT ACROSS THE BOARD.
SOUTHERLY WINDS WILL BE GUSTY ONCE AGAIN SATURDAY.
27
&&
.PREV DISCUSSION... /ISSUED 1001 PM CDT FRI MAY 31 2013/
UPDATE...FORECAST SEEMS TO BE IN GOOD SHAPE. STILL SOME
UNCERTAINTY HOW MUCH WILL BE LEFT OF THE CONVECTIVE SYSTEM OVER
MO WHEN IT APPROACHES MID TN TOWARD DAYBREAK. CURRENTLY WE HAVE
20 POPS NORTHWEST AND THIS SEEMS REASONABLE...AND IS SUPPORTED BY
THE LATEST HRRR AND NAM12. WE WILL CONTINUE TO MONITOR THE
PROGRESS AND NEW SHORT RANGE MODELS FOR POSSIBLE UPDATES. OTHER
ELEMENTS LOOK FINE WITH PARTLY CLOUDY SKIES AND LOWS IN THE LOWER
70S FOR MOST LOCATIONS.
13
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS SAN ANGELO TX
1155 PM CDT FRI MAY 31 2013
.DISCUSSION...
PLEASE SEE 06Z AVIATION DISCUSSION BELOW.
&&
.AVIATION...
LOW CLOUDS ARE ALREADY DEVELOPING JUST SOUTHEAST OF THE AREA...AND
THE NAM HAS A PRETTY GOOD HANDLE ON THIS SO FAR...SO WILL TREND
AVIATION FORECASTS TOWARD THE NAM GUIDANCE. THIS WILL BRING LOW
CLOUDS IN EARLY WHICH WAS ALREADY IN THE FORECAST...AND POSSIBLY
FARTHER NORTH...SO WILL INTRODUCE A TEMPO FOR LOW CLOUDS AT
KABI...AND A PREVAILING GROUP FOR MVFR CIGS AT KSJT FOR 3 TO 5
HOURS IS POSSIBLE. THE COLD FRONT CAN BE SEEN BEGINNING TO MAKE
PROGRESS SOUTH THROUGH THE TEXAS PANHANDLE. THIS FRONT IS STILL ON
TRACK TO MOVE THROUGH KABI DURING THE MORNING HOURS...AND THE REST
OF THE AREA DURING THE AFTERNOON HOURS. STILL EXPECT TO SEE
CONVECTION DEVELOP ALONG THE FRONT DURING THE AFTERNOON INTO THE
EVENING HOURS. MORE REFINEMENT TO THE CONVECTIVE FORECAST CAN BE
MADE IN FUTURE FORECAST ISSUANCES. 20
&&
.PREV DISCUSSION... /ISSUED 716 PM CDT FRI MAY 31 2013/
DISCUSSION...
SEE 00Z AVIATION DISCUSSION BELOW.
AVIATION...
SKIES WILL REMAIN CLEAR ACROSS THE AREA THROUGH THE EVENING HOURS.
MOISTURE WILL AGAIN MOVE NORTH INTO THE AREA OVERNIGHT
TONIGHT...BRINGING MVFR CIGS TO OUR SOUTHERN AND EASTERN TAF
SITES. THESE CIGS ARE EXPECTED TO MIX OUT BEFORE 18Z. A COLD FRONT
WILL MOVE INTO THE AREA TOMORROW AS WELL...LIKELY AFFECTING KABI
WITH NORTHERLY WINDS BY 15Z...KSJT BY 18Z...AND SOUTHERN SITES
AFTER 18Z. HAVE GONE AHEAD AND INSERTED VCTS TOMORROW AFTERNOON FOR
SOUTHERN AND EASTERN SITES WHERE THUNDERSTORMS ARE MORE LIKELY. 20
PREV DISCUSSION... /ISSUED 344 PM CDT FRI MAY 31 2013/
TONIGHT...
INSTABILITY WAS HIGH ACROSS WEST CENTRAL TEXAS WITH RAP ML CAPES
EXCEEDING 5000 J/KG. A STRONG CAP HOWEVER WAS PREVENTING STORM
DEVELOPMENT. I DID ADD A SLIGHT CHANCE OF THUNDERSTORMS IN HASKELL
AND THROCKMORTON COUNTIES THIS EVENING...WHERE A CUMULUS FIELD WAS
BEGINNING TO DEVELOP IN AN AREA OF WEAK SURFACE CONVERGENCE EAST
OF THE DRYLINE. AGAIN...LIKE YESTERDAY...IF STORMS DO
DEVELOP...THEY COULD RAPIDLY BECOME SEVERE WITH LARGE HAIL AND
DAMAGING WINDS. A TORNADO IS ALSO NOT OUT OF QUESTION WITH VERY
STRONG INSTABILITY PRESENT.
OTHERWISE A WARM NIGHT WITH LOW LEVEL MOISTURE CONTINUING TO FLOW
FROM THE GULF MEXICO. STRATUS RETURNS AFTER MIDNIGHT...FROM THE
HILL COUNTRY. 850 MB LOW LEVEL JET AGAIN PICKS UP TO 45-50 KTS
TOWARD MIDNIGHT. PERSISTENCE FORECAST TONIGHT WITH LOWS IN THE
LOWER TO MID 70S.
SATURDAY AND SUNDAY...
AS THE FRONT PUSHES SOUTH ACROSS THE AREA SATURDAY
MORNING...THINGS SHOULD STAY RELATIVELY QUITE. WITH DAYTIME
HEATING AND DEWPOINTS AROUND 70 DEGREES...SURFACE BASED CAPE WILL
INCREASE TO AROUND 3500 J/KG BY MID AFTERNOON. WITH THE FORCING
FROM THE FRONT...REALIZING THIS INSTABILITY SHOULD NOT BE A
PROBLEM. THE CIN VALUES ARE REASONABLE...HIGH ENOUGH TO ALLOW THE
INSTABILITY TO BUILD...BUT NOT TOO MUCH TO KEEP ANY OF IT FROM
BEING RELEASED. SHEAR WILL NOT BE SPECTACULAR...BUT WITH 30 KTS
THERE WILL BE ENOUGH FOR SUPPORT VIGOROUS UPDRAFTS. THE MAIN
THREAT WILL BE VERY LARGE HAIL. LOW LEVEL SHEAR IS
LACKLUSTER...ONLY MAYBE 10 KTS...SO THE TORNADO THREAT SHOULD BE
LIMITED...THOUGH IT CANNOT BE RULED OUT. IF A STORM CAN STAY ALONG
THE BOUNDARY FOR LONG ENOUGH...IT WILL BE POSSIBLE FOR A
CIRCULATION TO DEVELOP. THE MAIN AREA OF CONCERN IS THE
SOUTHEASTERN PART OF THE AREA...SOUTH OF A LINE FROM
BROWNWOOD...TO SAN ANGELO...TO OZONA. OTHERWISE...TEMPERATURES
WILL COOL OFF A LITTLE FROM FRIDAY BEHIND THE FRONT. HIGHS WILL
GENERALLY BE IN THE UPPER 80S TO LOWER 90S FOR SATURDAY AND
SUNDAY. LOWS WILL IN THE 60S TO LOWER 70S. RAIN CHANCES SHOULD
MOVE OUT BY EARLY AFTERNOON ON
SUNDAY NIGHT THROUGH FRIDAY...
RIDGE OF HIGH PRESSURE IN THE MID AND UPPER LEVELS ACROSS THE
ATMOSPHERE WILL BECOME ESTABLISHED FOR AT LEAST THE FIRST HALF OF
NEXT WEEK. TEMPERATURES WILL LIKELY SOAR WITH THE RIDGE...WITH THE
LOCATION OF THE THERMAL RIDGE SUGGESTING THAT READINGS AT LEAST
NEAR THE 100 DEGREE MARK ARE POSSIBLE FOR THE WESTERN HALF OF THE
AREA.
THE GFS WEAKENS THE RIDGE FOR THE LAST HALF OF THE WEEK...AND
TRIES ANOTHER FRONT AND CONVECTION INTO THE ARE FOR THURSDAY OR
FRIDAY. ECMWF SHOWS A LITTLE MORE PERSISTENT RIDGE...AND DELAYS
ANY CONVECTION TIL FRIDAY. AT THIS POINT...THINK KEEPING THE
FORECAST DRY FOR NOW IS PROBABLY THE BEST OPTION...AND LET THE
UNCERTAINTIES SETTLE A LITTLE.
&&
.PRELIMINARY POINT TEMPS/POPS...
ABILENE 73 90 65 89 66 / 10 20 30 10 10
SAN ANGELO 74 93 71 91 69 / 5 30 30 20 10
JUNCTION 73 94 70 92 68 / 5 30 40 20 10
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
321 AM CDT SAT JUN 1 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 321 AM CDT SAT JUN 1 2013
WHAT REMAINS OF THE CONVECTION IS DIMINISHING SLOWLY ACROSS THE
CENTRAL PART OF THE FORECAST AREA. EXPECT THIS TREND TO CONTINUE
THROUGH THE REMAINDER OF THE NIGHT. THE 01.05Z HRRR EVEN SUGGESTS
THE AREA WILL BE CLEAR OF ANY RAIN BY 12Z AND MAY NEED TO START
THE MORNING THAT WAY. AS THE DAY PROGRESSES...THE SURFACE LOW OVER
SOUTH DAKOTA MOVES ACROSS MINNESOTA INTO NORTHERN WISCONSIN AS THE
UPPER LEVEL LOW BECOMES AN OPEN WAVE. THE SHORT WAVE TROUGH SEEN
ON WATER VAPOR SATELLITE OVER SOUTH DAKOTA AND NEBRASKA WILL MOVE
ACROSS THE AREA. THE 01.00Z NAM INDICATES THIS WAVE WILL PRODUCE
UP TO 12 PVU/S OF VORTICITY ADVECTION IN THE 500-300 MB LAYER
DURING THE AFTERNOON. THE AREA WILL GET INTO THE DEFORMATION ON
THE BACK SIDE OF THE SURFACE LOW WITH SOME WEAK FRONTOGENESIS
DEVELOPING IN THE 1000-850 MB LAYER ALONG WITH SOME WEAK UP GLIDE
ON THE 295K SURFACE. THIS IS EXPECTED TO BE ENOUGH TO GENERATE
SOME SCATTERED SHOWERS DURING THE AFTERNOON AND WITH BETWEEN 200
AND 400 J/KG OF ML CAPE SOME ISOLATED THUNDERSTORMS SHOULD ALSO
DEVELOP. AS TEMPERATURES ALOFT COOL WITH THE PASSAGE OF THE UPPER
LEVEL TROUGH...THE FREEZING LEVEL WILL ALSO COME DOWN AND IF ANY
OF THE THUNDERSTORMS CAN DEVELOP A GOOD CORE ALOFT...SOME HAIL
WILL BE POSSIBLE. AS THE SYSTEM THEN MOVES AWAY FROM THE AREA
TONIGHT AND WITH THE LOSS OF THE CAPE...EXPECT THE ACTIVITY TO DIE
DOWN DURING THE EVENING WITH THE SHOWERS ENDING COMPLETELY AFTER
MIDNIGHT.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 321 AM CDT SAT JUN 1 2013
RIDGING ALOFT WILL BRIEFLY BUILD OVER THE UPPER MIDWEST FOR SUNDAY
AND MONDAY AND WITH HIGH PRESSURE AT THE SURFACE...A COUPLE OF DRY
DAYS ARE ANTICIPATED. THIS RIDGING THEN MOVES OFF AS ANOTHER
CLOSED UPPER LEVEL LOW APPROACHES FROM THE NORTHWEST. THIS SYSTEM
LOOKS TO BE ANOTHER SLOW MOVING SYSTEM AND WILL KEEP RAIN CHANCES
IN FOR AN EXTENDED TIME FROM MONDAY NIGHT THROUGH FRIDAY. UNLIKE
THE PAST SYSTEM...THIS ONE IS NOT EXPECTED TO PRODUCE NEARLY AS
MUCH HEAVY RAIN. THE 01.00Z GFS INDICATES PRECIPITABLE WATERS WITH
THIS SYSTEM WILL PRIMARILY BE IN THE 1 TO 1.25 INCH RANGE INSTEAD
OF 1.5 INCHES OR HIGHER AS WITH THE RECENT SYSTEM. ALSO...THE
01.00Z ECMWF SUGGESTS THAT AS THE SHORT WAVE TROUGHS ROTATE AROUND
THE UPPER LEVEL LOW...THE BULK OF THE FORCING WILL ACTUALLY BE
NORTH OF THE AREA FROM CENTRAL MINNESOTA AND NORTHWEST WISCONSIN
ON TO THE NORTH. ALSO NOT EXPECTING A LOT OF THUNDER FROM THIS
SYSTEM. NEITHER THE ECMWF OR GFS SHOW HARDLY ANY CAPE OVER THE AREA
FROM THIS SYSTEM AND THUS CUT THE THUNDER PROBABILITIES BACK TO
JUST HAVE ISOLATED AT BEST.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1201 AM CDT SAT JUN 1 2013
LOCAL RADAR SHOWING THE BULK OF THE ACTIVITY HAS NOW MOVED PAST
KRST BUT HAS YET TO IMPACT KLSE. WITH THE ACTIVITY SO CLOSE TO
KLSE PLAN TO START WITH A TEMPO GROUP TO COVER THE ACTIVITY COMING
WITH THE POSSIBILITY OF MVFR CEILINGS AND VISIBILITY WITH THE
THUNDERSTORMS. OBSERVATIONS BEHIND THE CONVECTION INDICATE
CONDITIONS GO BACK UP TO VFR WITH EITHER A HIGH BROKEN CEILING OR
JUST SCATTERED CLOUDS. AREA OF MVFR CEILINGS CLOSE TO THE
POSITION OF SURFACE LOW OVER SOUTH DAKOTA AT THIS TIME. THESE
CLOUDS ARE EXPECTED TO MOVE OVER BOTH TAF SITES BY MID MORNING AS
THE SURFACE LOW MOVES FROM EAST CENTRAL MINNESOTA INTO NORTHERN
WISCONSIN. WHAT SHOULD BE THE LAST SHORT WAVE TROUGH WILL COME
ACROSS THE REGION THIS AFTERNOON TO HELP GENERATE SOME WRAP AROUND
SHOWERS IN THE DEFORMATION AREA BEHIND THE SURFACE LOW. FOR
NOW...WILL SHOW THESE SHOWERS WITHOUT A VISIBILITY RESTRICTION.
THE COLD FRONT WILL MOVE THROUGH LATE IN THE AFTERNOON OR EARLY
EVENING SWINGING THE WINDS AROUND TO THE NORTHWEST. MAY STILL BE A
FEW SHOWERS AROUND WITH THE COLD FRONT SO WILL CARRY A VCSH
THROUGH THE EVENING...BUT EXPECTING THE SHOWERS WILL END SOONER
THAN THAT.
&&
.HYDROLOGY...
ISSUED AT 321 AM CDT SAT JUN 1 2013
THE RAINS FROM FRIDAY EVENING HAVE CAUSED SOME RESPONSE ON SOME
AREA RIVERS. RISES HAVE BEEN OCCURRING ON THE WHITEWATER
RIVER...CEDAR RIVER IN OSAGE AND THE ROOT RIVER. ENOUGH RAIN FELL
ACROSS PARTS OF SOUTHEAST MINNESOTA AND NORTHEAST IOWA FOR
ADDITIONAL WITHIN BANK RISES TO OCCUR. EARLIER RAINS ARE STILL
EXPECTED TO PUSH PARTS OF THE MISSISSIPPI...BLACK...TREMPEALEAU
AND UPPER IOWA RIVERS NEAR OR OVER FLOOD STAGE. FOR ADDITIONAL
DETAILS...SEE THE LATEST RIVER FLOOD STATEMENTS.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...04
LONG TERM...04
AVIATION...04
HYDROLOGY...04
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1201 AM CDT SAT JUN 1 2013
.UPDATE...
ISSUED AT 1001 PM CDT FRI MAY 31 2013
COMBINATION OF A SHORTWAVE LIFTING OUT OF CENTRAL INTO NORTHEAST
IOWA...A COLD FRONT CATCHING UP TO THE DRY-LINE...AND LINGERING
INSTABILITY ON THE ORDER OF 500-1500 J/KG PER RAP ANALYSIS HAS
ALLOWED ANOTHER ROUND OF CONVECTION TO OCCUR. THIS ROUND CONTAINS
MORE BOW ECHO SIGNATURES TO IT...THUS WINDS WILL BE A CONCERN.
SOME OF THE CELLS INITIALLY HAD GROWN QUITE TALL...RESULTING IN
LARGE HAIL...EVEN NEAR THE ROCHESTER AIRPORT. 0-1KM SHEAR NOW
RUNNING AROUND 25 KT...THUS POTENTIAL STILL EXISTS FOR
TORNADOES...ESPECIALLY ON INFLOW NOTCHES OF THE BOWS.
INSTABILITY SHOULD WANE OVER THE NEXT FEW HOURS WITH NIGHT TIME
COOLING. ADDITIONALLY...THE SHORTWAVE WILL BE MOVING THROUGH THE
AREA...ALLOWING SUBSIDENCE TO COME IN ON ITS BACK SIDE AND ALSO
HELP TO PUT AN END TO THE SEVERE WEATHER. PER COLLABORATION WITH
SPC...MPX AND GRB...HAVE EXTENDED SEVERE THUNDERSTORM WATCH 261
UNTIL MIDNIGHT.
&&
.SHORT TERM...(TONIGHT THROUGH SATURDAY NIGHT)
ISSUED AT 227 PM CDT FRI MAY 31 2013
WATER VAPOR IMAGERY/RAP ANALYSIS THIS AFTERNOON SHOWING A CLOSED LOW
OVER THE DAKOTAS WITH AN EMBEDDED SHORTWAVE TROUGH ROTATING
NORTHEAST ACROSS IA. THIS WAS KICKING OFF CONVECTION ACROSS PORTIONS
OF SOUTHEAST MN/NORTHEAST IA WHERE LAPS WAS PRODUCING AN AXIS OF
1000-1500J/KG 0-1KM MLCAPE. 0-6KM BULK SHEAR WAS RUNNING AROUND
65KT. CONVECTION...SOME SEVERE WITH INCREASING CAPE AND HIGHER-END
BULK SHEAR...WILL CONTINUE TO DEVELOP LATE THIS AFTERNOON AND CONTINUE
INTO THIS EVENING AS THE TROUGH ROTATES NORTHEAST THROUGH THE AREA.
LARGE HAIL AND DAMAGING WINDS LOOK TO BE THE MAIN THREAT WITH AN
ISOLATED TORNADO ALSO POSSIBLE. LOOK FOR THE BULK OF THE
SHOWER/THUNDERSTORM ACTIVITY TO PUSH EAST OF THE AREA BY MIDNIGHT.
LOOK FOR THE CLOSED LOW TO FILL AS IT ROTATES INTO THE AREA ON
SATURDAY. STEEP LOW TO MID LEVEL LAPSE RATE ASSOCIATED WITH THE
COOL/CYCLONIC FLOW WILL BE THE IMPETUS FOR MORE SHOWER AND ISOLATED
THUNDERSTORM DEVELOPMENT...ESPECIALLY GOING INTO THE AFTERNOON
HOURS. NAM INDICATING 0-1KM MLCAPE IN THE 150-300J/KG RANGE WITH ANY
DECENT BULK SHEAR SHIFTING ACROSS EASTERN WI. THIS SHOULD LIMIT THE
POTENTIAL FOR ANY SEVERE THUNDERSTORM THREAT. OTHERWISE...EXPECT
MOSTLY CLOUDY CONDITIONS BY AFTERNOON WITH HIGHS RANGING FROM THE
65-70 DEGREE ACROSS NORTHEAST IA/SOUTHEAST MN...TO THE 70-75 DEGREE
RANGE EAST OF THE MISSISSIPPI RIVER.
SCATTERED SHOWERS ARE EXPECTED TO LINGER INTO SATURDAY NIGHT AS THE
MID-LEVEL TROUGH AXIS ROTATES EAST THROUGH THE AREA WITH OVERNIGHT
LOWS DROPPING INTO THE 40S AND LOWER 50S.
.LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY)
ISSUED AT 227 PM CDT FRI MAY 31 2013
HIGH PRESSURE WILL BUILD INTO THE AREA SUNDAY THROUGH MONDAY FOR A
MUCH DESERVED PERIOD OF DRY WEATHER. TEMPERATURES ARE EXPECTED TO BE
A BIT ON THE COOLER THAN NORMAL SIDE THOUGH WITH HIGHS MAINLY IN THE
60S. LOWS SUNDAY NIGHT ARE EXPECTED TO DIP INTO THE LOWER 40S ALONG
AND NORTHEAST OF I-94...TO THE MID/UPPER 40S ELSEWHERE.
FOR TUESDAY THROUGH THURSDAY...ANOTHER CLOSED LOW IS SLATED TO MOVE
FROM THE NORTHERN PLAINS AND THROUGH THE UPPER MISSISSIPPI RIVER
REGION. THIS WILL GIVE THE AREA ANOTHER ROUND OF SHOWERS AND
THUNDERSTORMS ALONG WITH OVERALL COOLER THAN NORMAL TEMPERATURES.
MODELS ARE INDICATING THE LOW LIFTING OUT OF THE AREA THURSDAY
NIGHT/FRIDAY TIME FRAME. LEFT A SMALL CHANCE OF SHOWERS IN FOR NOW
AND WILL PASS ALONG TO LATER SHIFTS FOR THE POSSIBILITY OF DRYING
THINGS OUT.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1201 AM CDT SAT JUN 1 2013
LOCAL RADAR SHOWING THE BULK OF THE ACTIVITY HAS NOW MOVED PAST
KRST BUT HAS YET TO IMPACT KLSE. WITH THE ACTIVITY SO CLOSE TO
KLSE PLAN TO START WITH A TEMPO GROUP TO COVER THE ACTIVITY COMING
WITH THE POSSIBILITY OF MVFR CEILINGS AND VISIBILITY WITH THE
THUNDERSTORMS. OBSERVATIONS BEHIND THE CONVECTION INDICATE
CONDITIONS GO BACK UP TO VFR WITH EITHER A HIGH BROKEN CEILING OR
JUST SCATTERED CLOUDS. AREA OF MVFR CEILINGS CLOSE TO THE
POSITION OF SURFACE LOW OVER SOUTH DAKOTA AT THIS TIME. THESE
CLOUDS ARE EXPECTED TO MOVE OVER BOTH TAF SITES BY MID MORNING AS
THE SURFACE LOW MOVES FROM EAST CENTRAL MINNESOTA INTO NORTHERN
WISCONSIN. WHAT SHOULD BE THE LAST SHORT WAVE TROUGH WILL COME
ACROSS THE REGION THIS AFTERNOON TO HELP GENERATE SOME WRAP AROUND
SHOWERS IN THE DEFORMATION AREA BEHIND THE SURFACE LOW. FOR
NOW...WILL SHOW THESE SHOWERS WITHOUT A VISIBILITY RESTRICTION.
THE COLD FRONT WILL MOVE THROUGH LATE IN THE AFTERNOON OR EARLY
EVENING SWINGING THE WINDS AROUND TO THE NORTHWEST. MAY STILL BE A
FEW SHOWERS AROUND WITH THE COLD FRONT SO WILL CARRY A VCSH
THROUGH THE EVENING...BUT EXPECTING THE SHOWERS WILL END SOONER
THAN THAT.
&&
.HYDROLOGY...
ISSUED AT 227 PM CDT FRI MAY 31 2013
WITH THE ATMOSPHERE BECOMING PROGRESSIVELY DRIER TONIGHT THROUGH
SATURDAY NIGHT...LOOK FOR RAINFALL AMOUNTS TO BE SUBSTANTIALLY LOWER
WITH ANY SHOWERS/THUNDERSTORMS THAT DEVELOP. THEREFORE...RUNOFF IS
EXPECTED TO BE LESS OF AN ISSUE GOING INTO THIS WEEKEND. AS OF THIS
AFTERNOON...SEVERAL RIVERWAYS INCLUDING THE TURKEY...UPPER
IOWA...AND TREMPEALEAU STILL HAVE ONGOING FLOODING. FOR FURTHER
DETAILS...PLEASE SEE THE LATEST RIVER FLOOD STATEMENTS.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
UPDATE...AJ
SHORT TERM...DAS
LONG TERM...DAS
AVIATION...04
HYDROLOGY...DAS
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
651 PM CDT FRI MAY 31 2013
.MESOSCALE DISCUSSION...
ISSUED AT 637 PM CDT FRI MAY 31 2013
A LINE OF SCATTERED THUNDERSTORMS HAS FIRED UP FROM WEST OF EAU
CLAIRIE WI TO EAST OF ROCHESTER MN AND CHARLES CITY IA. THESE
STORMS ARE ALONG A DRY LINE. THEY TOOK A LITTLE BIT TO REALLY GET
GOING...APPEARING TO WAIT FOR A 300MB JET STREAK COMING UP THROUGH
CENTRAL IA TO AID IN UPPER LEVEL DIVERGENCE. NCAPE VALUES ARE
QUITE HIGH...AROUND 0.25 PER RAP ANALYSIS...WHICH WOULD FAVOR
RAPID THUNDERSTORM DEVELOPMENT GIVEN THE FORCING. THIS MAY BE A
REASON WHY THE STORMS IN WABASHA...WINONA AND BUFFALO
COUNTIES...AS WELL AS FLOYD...MITCHELL AND HOWARD COUNTIES IN
IOWA. THE STORM IN NORTHEAST IOWA HAS HAD A HISTORY OF FUNNELS.
0-1KM SHEAR HAS INCREASED...TOWARDS 15-20 KT...SO WILL HAVE TO
MONITOR POTENTIAL FOR TORNADOES.
&&
.SHORT TERM...(TONIGHT THROUGH SATURDAY NIGHT)
ISSUED AT 227 PM CDT FRI MAY 31 2013
WATER VAPOR IMAGERY/RAP ANALYSIS THIS AFTERNOON SHOWING A CLOSED LOW
OVER THE DAKOTAS WITH AN EMBEDDED SHORTWAVE TROUGH ROTATING
NORTHEAST ACROSS IA. THIS WAS KICKING OFF CONVECTION ACROSS PORTIONS
OF SOUTHEAST MN/NORTHEAST IA WHERE LAPS WAS PRODUCING AN AXIS OF
1000-1500J/KG 0-1KM MLCAPE. 0-6KM BULK SHEAR WAS RUNNING AROUND
65KT. CONVECTION...SOME SEVERE WITH INCREASING CAPE AND HIGHER-END
BULK SHEAR...WILL CONTINUE TO DEVELOP LATE THIS AFTERNOON AND CONTINUE
INTO THIS EVENING AS THE TROUGH ROTATES NORTHEAST THROUGH THE AREA.
LARGE HAIL AND DAMAGING WINDS LOOK TO BE THE MAIN THREAT WITH AN
ISOLATED TORNADO ALSO POSSIBLE. LOOK FOR THE BULK OF THE
SHOWER/THUNDERSTORM ACTIVITY TO PUSH EAST OF THE AREA BY MIDNIGHT.
LOOK FOR THE CLOSED LOW TO FILL AS IT ROTATES INTO THE AREA ON
SATURDAY. STEEP LOW TO MID LEVEL LAPSE RATE ASSOCIATED WITH THE
COOL/CYCLONIC FLOW WILL BE THE IMPETUS FOR MORE SHOWER AND ISOLATED
THUNDERSTORM DEVELOPMENT...ESPECIALLY GOING INTO THE AFTERNOON
HOURS. NAM INDICATING 0-1KM MLCAPE IN THE 150-300J/KG RANGE WITH ANY
DECENT BULK SHEAR SHIFTING ACROSS EASTERN WI. THIS SHOULD LIMIT THE
POTENTIAL FOR ANY SEVERE THUNDERSTORM THREAT. OTHERWISE...EXPECT
MOSTLY CLOUDY CONDITIONS BY AFTERNOON WITH HIGHS RANGING FROM THE
65-70 DEGREE ACROSS NORTHEAST IA/SOUTHEAST MN...TO THE 70-75 DEGREE
RANGE EAST OF THE MISSISSIPPI RIVER.
SCATTERED SHOWERS ARE EXPECTED TO LINGER INTO SATURDAY NIGHT AS THE
MID-LEVEL TROUGH AXIS ROTATES EAST THROUGH THE AREA WITH OVERNIGHT
LOWS DROPPING INTO THE 40S AND LOWER 50S.
.LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY)
ISSUED AT 227 PM CDT FRI MAY 31 2013
HIGH PRESSURE WILL BUILD INTO THE AREA SUNDAY THROUGH MONDAY FOR A
MUCH DESERVED PERIOD OF DRY WEATHER. TEMPERATURES ARE EXPECTED TO BE
A BIT ON THE COOLER THAN NORMAL SIDE THOUGH WITH HIGHS MAINLY IN THE
60S. LOWS SUNDAY NIGHT ARE EXPECTED TO DIP INTO THE LOWER 40S ALONG
AND NORTHEAST OF I-94...TO THE MID/UPPER 40S ELSEWHERE.
FOR TUESDAY THROUGH THURSDAY...ANOTHER CLOSED LOW IS SLATED TO MOVE
FROM THE NORTHERN PLAINS AND THROUGH THE UPPER MISSISSIPPI RIVER
REGION. THIS WILL GIVE THE AREA ANOTHER ROUND OF SHOWERS AND
THUNDERSTORMS ALONG WITH OVERALL COOLER THAN NORMAL TEMPERATURES.
MODELS ARE INDICATING THE LOW LIFTING OUT OF THE AREA THURSDAY
NIGHT/FRIDAY TIME FRAME. LEFT A SMALL CHANCE OF SHOWERS IN FOR NOW
AND WILL PASS ALONG TO LATER SHIFTS FOR THE POSSIBILITY OF DRYING
THINGS OUT.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 650 PM CDT FRI MAY 31 2013
SCATTERED THUNDERSTORMS HAVE FORMED ACROSS SOUTHEAST MINNESOTA...
SOME AHEAD OF A DRY LINE AND OTHERS AHEAD OF A COLD FRONT. RIGHT
NOW BOTH TAF SITES ARE NOT BEING AFFECTED... HOWEVER...AM
ANTICIPATING THAT BOTH COULD SEE SHOWERS AND/OR STORMS WITHIN THE
NEXT FEW HOURS. HAVE COVERED THAT WITH VCTS FOR NOW GIVEN THE
SCATTERED NATURE. IF THE STORMS ORGANIZE INTO A MORE CONGEALED
LINE...WILL AMEND THE TAFS TO PUT THE TSRA. THESE STORMS COULD
PRODUCE LARGE HAIL AND STRONG WINDS. THE COLD FRONT ITSELF IS BACK
JUST WEST OF I-35. ONCE THE FRONT PASSES LATE THIS
EVENING...EXPECT MUCH OF THE PRECIPITATION CONCERN TO END. MVFR
STRATUS BECOMES THE NEXT ISSUE...ASSOCIATED WITH LOW PRESSURE IN
THE DAKOTAS MOVING TO THE EAST. IT APPEARS THIS STRATUS WILL GET
INTO RST AROUND 13Z. THE VALLEY LOCATION OF LSE SHOULD KEEP THE
CEILINGS VFR. A SECONDARY COLD FRONTAL PASSAGE LOOKS TO MOVE
THROUGH THE TAF SITES LATE IN THE DAY. IN ITS WAKE...SHOWERS AND
POSSIBLY EVEN A FEW THUNDERSTORMS SHOULD MOVE INTO THE TAF SITES.
HAVE ONLY INCLUDED THE -SHRA AT THIS TIME...SINCE THUNDERSTORM
UNCERTAINTY IS QUITE HIGH.
&&
.HYDROLOGY...
ISSUED AT 227 PM CDT FRI MAY 31 2013
WITH THE ATMOSPHERE BECOMING PROGRESSIVELY DRIER TONIGHT THROUGH
SATURDAY NIGHT...LOOK FOR RAINFALL AMOUNTS TO BE SUBSTANTIALLY LOWER
WITH ANY SHOWERS/THUNDERSTORMS THAT DEVELOP. THEREFORE...RUNOFF IS
EXPECTED TO BE LESS OF AN ISSUE GOING INTO THIS WEEKEND. AS OF THIS
AFTERNOON...SEVERAL RIVERWAYS INCLUDING THE TURKEY...UPPER
IOWA...AND TREMPEALEAU STILL HAVE ONGOING FLOODING. FOR FURTHER
DETAILS...PLEASE SEE THE LATEST RIVER FLOOD STATEMENTS.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
MESOSCALE...AJ
SHORT TERM...DAS
LONG TERM...DAS
AVIATION...AJ
HYDROLOGY...DAS
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
637 PM CDT FRI MAY 31 2013
.MESOSCALE DISCUSSION...
ISSUED AT 637 PM CDT FRI MAY 31 2013
A LINE OF SCATTERED THUNDERSTORMS HAS FIRED UP FROM WEST OF EAU
CLAIRIE WI TO EAST OF ROCHESTER MN AND CHARLES CITY IA. THESE
STORMS ARE ALONG A DRY LINE. THEY TOOK A LITTLE BIT TO REALLY GET
GOING...APPEARING TO WAIT FOR A 300MB JET STREAK COMING UP THROUGH
CENTRAL IA TO AID IN UPPER LEVEL DIVERGENCE. NCAPE VALUES ARE
QUITE HIGH...AROUND 0.25 PER RAP ANALYSIS...WHICH WOULD FAVOR
RAPID THUNDERSTORM DEVELOPMENT GIVEN THE FORCING. THIS MAY BE A
REASON WHY THE STORMS IN WABASHA...WINONA AND BUFFALO
COUNTIES...AS WELL AS FLOYD...MITCHELL AND HOWARD COUNTIES IN
IOWA. THE STORM IN NORTHEAST IOWA HAS HAD A HISTORY OF FUNNELS.
0-1KM SHEAR HAS INCREASED...TOWARDS 15-20 KT...SO WILL HAVE TO
MONITOR POTENTIAL FOR TORNADOES.
&&
.SHORT TERM...(TONIGHT THROUGH SATURDAY NIGHT)
ISSUED AT 227 PM CDT FRI MAY 31 2013
WATER VAPOR IMAGERY/RAP ANALYSIS THIS AFTERNOON SHOWING A CLOSED LOW
OVER THE DAKOTAS WITH AN EMBEDDED SHORTWAVE TROUGH ROTATING
NORTHEAST ACROSS IA. THIS WAS KICKING OFF CONVECTION ACROSS PORTIONS
OF SOUTHEAST MN/NORTHEAST IA WHERE LAPS WAS PRODUCING AN AXIS OF
1000-1500J/KG 0-1KM MLCAPE. 0-6KM BULK SHEAR WAS RUNNING AROUND
65KT. CONVECTION...SOME SEVERE WITH INCREASING CAPE AND HIGHER-END
BULK SHEAR...WILL CONTINUE TO DEVELOP LATE THIS AFTERNOON AND CONTINUE
INTO THIS EVENING AS THE TROUGH ROTATES NORTHEAST THROUGH THE AREA.
LARGE HAIL AND DAMAGING WINDS LOOK TO BE THE MAIN THREAT WITH AN
ISOLATED TORNADO ALSO POSSIBLE. LOOK FOR THE BULK OF THE
SHOWER/THUNDERSTORM ACTIVITY TO PUSH EAST OF THE AREA BY MIDNIGHT.
LOOK FOR THE CLOSED LOW TO FILL AS IT ROTATES INTO THE AREA ON
SATURDAY. STEEP LOW TO MID LEVEL LAPSE RATE ASSOCIATED WITH THE
COOL/CYCLONIC FLOW WILL BE THE IMPETUS FOR MORE SHOWER AND ISOLATED
THUNDERSTORM DEVELOPMENT...ESPECIALLY GOING INTO THE AFTERNOON
HOURS. NAM INDICATING 0-1KM MLCAPE IN THE 150-300J/KG RANGE WITH ANY
DECENT BULK SHEAR SHIFTING ACROSS EASTERN WI. THIS SHOULD LIMIT THE
POTENTIAL FOR ANY SEVERE THUNDERSTORM THREAT. OTHERWISE...EXPECT
MOSTLY CLOUDY CONDITIONS BY AFTERNOON WITH HIGHS RANGING FROM THE
65-70 DEGREE ACROSS NORTHEAST IA/SOUTHEAST MN...TO THE 70-75 DEGREE
RANGE EAST OF THE MISSISSIPPI RIVER.
SCATTERED SHOWERS ARE EXPECTED TO LINGER INTO SATURDAY NIGHT AS THE
MID-LEVEL TROUGH AXIS ROTATES EAST THROUGH THE AREA WITH OVERNIGHT
LOWS DROPPING INTO THE 40S AND LOWER 50S.
.LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY)
ISSUED AT 227 PM CDT FRI MAY 31 2013
HIGH PRESSURE WILL BUILD INTO THE AREA SUNDAY THROUGH MONDAY FOR A
MUCH DESERVED PERIOD OF DRY WEATHER. TEMPERATURES ARE EXPECTED TO BE
A BIT ON THE COOLER THAN NORMAL SIDE THOUGH WITH HIGHS MAINLY IN THE
60S. LOWS SUNDAY NIGHT ARE EXPECTED TO DIP INTO THE LOWER 40S ALONG
AND NORTHEAST OF I-94...TO THE MID/UPPER 40S ELSEWHERE.
FOR TUESDAY THROUGH THURSDAY...ANOTHER CLOSED LOW IS SLATED TO MOVE
FROM THE NORTHERN PLAINS AND THROUGH THE UPPER MISSISSIPPI RIVER
REGION. THIS WILL GIVE THE AREA ANOTHER ROUND OF SHOWERS AND
THUNDERSTORMS ALONG WITH OVERALL COOLER THAN NORMAL TEMPERATURES.
MODELS ARE INDICATING THE LOW LIFTING OUT OF THE AREA THURSDAY
NIGHT/FRIDAY TIME FRAME. LEFT A SMALL CHANCE OF SHOWERS IN FOR NOW
AND WILL PASS ALONG TO LATER SHIFTS FOR THE POSSIBILITY OF DRYING
THINGS OUT.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON) ISSUED
AT 1248 PM CDT FRI MAY 31 2013
THE MAIN FOCUS AT THE TAF SITES IS WITH THE TIMING ON WHEN ANY
SHOWERS OR THUNDERSTORMS WILL GET INTO THE TAF SITES. SHOWERS HAVE
ALREADY DEVELOPED NEAR RST AND WILL DRIFT TO THE EAST THROUGH THE
AFTERNOON. WITH AN UNSTABLE ENVIRONMENT IN PLACE...THESE SHOWERS
WILL QUICKLY STRENGTHEN EARLY THIS AFTERNOON WITH THUNDERSTORMS
LIKELY AT RST BETWEEN 19Z/23Z. AS THE STORMS MARCH EAST...THEY
SHOULD REACH LSE SOMETIME BETWEEN 23Z AND 02Z. MVFR CUMULUS FIELD
WILL LIKELY STAY IN PLACE OR GRADUALLY CLIMB THIS AFTERNOON BEFORE
MVFR/IFR CONDITIONS COME IN WITH THE THUNDERSTORMS. CONDITIONS
SHOULD CLEAR OUT LATER THIS EVENING WITH WINDS SUBSIDING
OVERNIGHT.
&&
.HYDROLOGY...
ISSUED AT 227 PM CDT FRI MAY 31 2013
WITH THE ATMOSPHERE BECOMING PROGRESSIVELY DRIER TONIGHT THROUGH
SATURDAY NIGHT...LOOK FOR RAINFALL AMOUNTS TO BE SUBSTANTIALLY LOWER
WITH ANY SHOWERS/THUNDERSTORMS THAT DEVELOP. THEREFORE...RUNOFF IS
EXPECTED TO BE LESS OF AN ISSUE GOING INTO THIS WEEKEND. AS OF THIS
AFTERNOON...SEVERAL RIVERWAYS INCLUDING THE TURKEY...UPPER
IOWA...AND TREMPEALEAU STILL HAVE ONGOING FLOODING. FOR FURTHER
DETAILS...PLEASE SEE THE LATEST RIVER FLOOD STATEMENTS.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
MESOSCALE...AJ
SHORT TERM...DAS
LONG TERM...DAS
AVIATION...HALBACH
HYDROLOGY...DAS
AREA FORECAST DISCUSSION...CORRECTED
NWS MILWAUKEE/SULLIVAN WI
446 PM CDT THU MAY 30 2013
.SHORT TERM...
.TONIGHT AND FRIDAY...FORECAST CONFIDENCE MEDIUM.
ONGOING SCATTERED CONVECTION WITH MORE DISCRETE-TYPE CELLS
ASSOCIATED WITH A VORT MAX ROTATING AROUND A NEGATIVELY TILTED 500MB
UPPER LOW OVER THE NORTHERN PLAINS...AND ON THE NOSE OF THE 850MB
LOW LEVEL JET. MOST OF THE SEVERE THUNDERSTORM WARNINGS HAVE BEEN
LARGE HAIL AND THE TOKEN DAMAGING WINDS. DECENT LOW LEVEL SHEAR AND
CAPE STILL WARRANTS TORNADO WATCH. WEAK TORNADOES ARE POSSIBLE. THE
STORMS MAY CONGEAL INTO BOWING LINE SEGMENTS LATER THIS AFTERNOON AS
THEY GET INTO SOUTHEAST WI PER THE 17Z HRRR MODEL RUN.
MEANWHILE... A STRONGER VORT MAX CURRENTLY OVER MISSOURI WILL ROLL
ACROSS IOWA AROUND 00Z. STORMS AHEAD OF THIS DISTURBANCE WILL MOST
LIKELY BE IN A LINE/MCS MODE AS IT REACHES NORTHERN IL/SOUTHERN WI.
EXPECTING THIS TO MOVE ACROSS ALL OF THE MKX AREA THIS EVENING.
LATEST 17Z HRRR SPED THIS UP WITH THE LEADING EDGE CLEARING EASTERN
WI BY 03Z...WHILE THE 12Z NAM DELAYS IT OVER THE MKX AREA FROM
03-09Z.
EXPECT A BREAK IN PRECIP LATE TONIGHT INTO FRIDAY MORNING AFTER THIS
SECONDARY ROUND. THEN WE WILL BE IN ANOTHER FAVORABLE SYNOPTIC SETUP
FOR MORE SEVERE STORMS ON FRIDAY. THE 500MB UPPER LOW WILL SHIFT A
LITTLE CLOSER INTO THE EASTERN DAKOTAS AND ANOTHER VORT MAX WILL
SWING INTO SOUTHERN WI AS THE LEFT EXIT REGION OF A 100KT UPPER JET
MOVES THROUGH. CONVECTIVE MODE WILL LIKELY BE A LINE OF STORMS WITH
A SUBTLE COLD-FRONT. DAMAGING WINDS THE MAIN SEVERE THREAT.
ONE UNCERTAINTY WITH FRIDAY THUNDERSTORMS WILL BE THAT THE LINE
COULD FORM IN ILLINOIS AND MOVE EAST AND JUST CLIP SOUTHEAST WI OR
EVEN MISS IT ALL TOGETHER.
FRIDAY NIGHT AND THROUGH SATURDAY...FORECAST CONFIDENCE...MEDIUM
TO HIGH
THE MID/UPPER TROUGH WILL PUSH INTO THE UPPER MISSISSIPPI VALLEY
REGION. THE 250 MB JET MAX INCREASES TO 100 KNOTS ACROSS SOUTHERN
AND NORTHEAST WISCONSIN WITH MODERATE UPPER DIVERGENCE OVER
SOUTHEAST WISCONSIN DURING THE EVENING.
SOUTHERN WISCONSIN WILL REMAIN IN THE WARM SECTOR FRIDAY EVENING
WITH A MID DRY PUNCH OVER MUCH OF THE AREA. THOUGH THE BEST LOW
LEVEL WIND MAX WILL BE TO THE SOUTH AND EAST...STRONGER STORMS
ARE NOT OUT OF THE QUESTION ESPECIALLY WITH WIND SHEAR A BIT
HIGHER THAN PREVIOUS DAYS. THE CWASP SEVERE PARAMETER IS HIGHEST
ACROSS NORTHEAST ILLINOIS LOWER VALUES EXTENDS CLOSER TO THE UPPER
LOW OVER PORTIONS OF SOUTH CENTRAL WISCONSIN.
WEAKENING LOW PRESSURE WILL FINALLY DRAG A COLD FRONT THROUGH
SOUTHERN WISCONSIN BY SATURDAY NIGHT. NAM FORECAST SOUNDINGS STILL
HAVE 1300 J/KM OF CAPE SATURDAY AFTERNOON IF FORECAST DEW POINTS
ARE NOT TOO HIGH.
.LONG TERM...
SUNDAY THROUGH THURSDAY...FORECAST CONFIDENCE...MEDIUM TO HIGH
MAIN UPPER LEVEL TROUGH AXIS WILL MOVE ACROSS THE WESTERN GREAT LAKES
SATURDAY NIGHT THEN INTO SOUTHERN CANADA ON SUNDAY.
FORECAST SOUNDINGS SHOW MOISTURE TRAPPED BELOW AN INVERSION AROUND
7 THSD FT...SO EXPECT CUMULUS/STRATOCUMULUS SUNDAY. COOLER AIR IS
EXPECTED TO ARRIVE WITH THE SHORTWAVE.
THE GFS AND ECMWF ARE FAIRLY SIMILAR IN BRINGING ANOTHER UPPER
TROUGH ACROSS THE NORTHERN PLAINS MONDAY NIGHT AND REACHING THE
UPPER MISSISSIPPI VALLEY WEDNESDAY. ON THURSDAY THE GFS BRINGS THE
UPPER TROUGH ACROSS WISCONSIN WITH A BROADER MORE NORTH LOCATION
ON THE 00Z ECMWF.
STILL SOME POTENTIAL OF INSTABILITY SHOWERS SUNDAY BEFORE HIGH
PRESSURE DOMINATES WISCONSIN MONDAY.
BY TUESDAY SHOWERS/THUNDERSTORMS APPROACH THE MISSISSIPPI RIVER AREA
TUESDAY EVENING WITH A CHANCE OF SHOWERS/THUNDERSTORMS WEDNESDAY
AND THURSDAY.
&&
EXPECT GUSTS BETWEEN 25 AND 30 KTS TO PERSIST UNTIL EVENING AS
MIXING CEASES. DISCRETE THUNDERSTORMS WITH SOME PRODUCING LARGE HAIL
MAINLY IN SOUTH CENTRAL WI. EXPECTING STORMS TO CONGEAL AT SOME
POINT AND STRAIGHT-LINE WINDS WILL BECOME THE MAIN THREAT FOR ALL OF
SOUTH CENTRAL AND SOUTHEAST WI. STORMS ARE DEVELOPING RAPIDLY...SO
WATCH THE RADAR CLOSELY FOR NEW DEVELOPMENTS. WEAK TORNADOES ARE
POSSIBLE WITH DECENT LOW-LEVEL ROTATION.
ANOTHER ROUND...A LINE OF THUNDERSTORMS...IS EXPECTED EARLY THIS
EVENING AND THESE WILL LIKELY SPREAD ALL THE WAY ACROSS SOUTHERN WI.
STRAIGHT-LINE WINDS WILL BE THE MAIN SEVERE WEATHER THREAT.
AFTER A BREAK LATE TONIGHT/EARLY FRIDAY...EXPECT A LINE OF
THUNDERSTORMS TO DEVELOP ALONG A WEAK COLD FRONT SOMEWHERE IN IA/IL
AND TRACK ENE MIDDAY FRIDAY. THESE MAY SWEEP ACROSS ALL OF SOUTHERN
WI OR JUST CLIP SOUTHEAST WI. STAY TUNED TO THE FORECAST FOR THIS
ONE.
&&
.MARINE...
GUSTY SOUTH WINDS DUE TO MIXING OVER THE LAND WILL AFFECT SHORELINE
NEARSHORE AREAS UNTIL THIS EVENING. WINDS WILL BE LESS GUSTY TOWARD
THE OPEN WATERS. HOWEVER...THE TIGHT PRESSURE GRADIENT OVER THE LAKE
WILL ALLOW SUSTAINED WINDS TO BE IN THE 15 TO 20 KNOT RANGE TODAY
AND TONIGHT. STABLE AIR DOWN AT LAKE LEVEL WILL KEEP WAVES FROM
RESPONDING TOO MUCH TO THE GUSTY WINDS.
THUNDERSTORMS EXPECTED THIS EVENING AND AGAIN FRIDAY MIDDAY AND
AGAIN SOMETIME ON SATURDAY.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...NONE.
&&
$$
TONIGHT/FRIDAY AND AVIATION/MARINE...MRC
FRIDAY NIGHT THROUGH THURSDAY...HENTZ
AREA FORECAST DISCUSSION...UPDATED
NWS MILWAUKEE/SULLIVAN WI
159 PM CDT THU MAY 30 2013
.UPDATE...
18Z DVN SOUNDING CAME IN WITH SBCAE AROUND 2000 J/KG AND INCREASE
IN FLOW IN THE LOWEST 6 KM. 50-60 KNOT WINDS WERE NOTED IN THE
800-500 MB LAYER. FLOW WAS MAINLY UNIDIRECTIONAL AND THE PRIMARY
WEAKNESS FOR TORNADIC SUPERCELLS WAS THE WEAK FLOW UP AROUND ANVIL
LEVEL...WHICH WOULD FAVOR HP TYPE STORMS WITH MORE WIND THREAT.
HOWEVER...0-3KM SHEAR OF 30-40 KNOTS WOULD SUPPORT THREAT FOR
MESOVORTEX/QLCS TORNADO THREAT GIVEN LCL OF 1000M OR LESS AND
0-1KM SHEAR OF 20-25 KNOTS.
RUC13 1 HOUR FORECAST FOR 19Z HAS SIG TORNADO PARAMETER OF 3-4
ACROSS NORTHERN ILLINOIS WITH VALUES OF 1-2 ACROSS SOUTHERN
WISCONSIN. THUS CONTINUED THREAT FOR WIND DAMAGE...TORNADOES...AND
SEVERE HAIL FOR NEXT FEW HOURS.
HIGH LEVEL FLOW SHOULD INCREASE ON NOSE OF DIFFLUENT UPPER JET BY
THIS EVENING AND WOULD SUPPORT INCREASING THREAT FOR TORNADIC
SUPERCELLS IF THE ACTIVITY CAN REMAIN DISCRETE.
&&
.PREV DISCUSSION... /ISSUED 1259 PM CDT THU MAY 30 2013/
UPDATE...
TORNADO WATCH IN EFFECT FOR SOUTH CENTRAL WI...INCLUDING
MARQUETTE/GREEN LAKE COUNTIES THROUGH DANE AND ROCK COUNTIES AND
WEST TO SAUK AND LAFAYETTE COUNTIES. SCATTERED CONVECTION IS
DEVELOPING IN SOUTH CENTRAL WI AS THE 850MB LOW LEVEL JET POINTS
INTO THE REGION. DEEP SHEAR IS STILL WEAK...BUT LOW LEVEL SHEAR IS
HIGH IN THE 20 TO 30 KNOT RANGE. 0-3KM CAPE IS DECENT WITH VALUES OVER
100 J/KG.
ENVIRONMENT IS CONDUCIVE FOR RAPID INTENSIFICATION OF ISOLATED
STORMS. THE LOW LCL AND HIGH 0-3 AND 0-1 HELICITY VALUES SUPPORT
TORNADO POTENTIAL. LARGE HAIL IS LIKELY IN THESE ISOLATED CELLS AS
WELL. CIMSS CLOUD TOP COOLING HIGHLIGHTED AN AREA OF RAPID COOLING
IN WESTERN SAUK COUNTY AT 1225 PM AND A SEVERE THUNDERSTORM WARNING
WAS ISSUED ON IT FOR 1-INCH HAIL A FEW MINUTES AGO.
THE 16Z HRRR SHOWS SCATTERED CONVECTION OVER SOUTH CENTRAL WI
EVOLVING INTO A LINE OVER SOUTHEAST WI AROUND 21Z. THE STRONG VORT
MAX SWINGING UP HERE LATER SHOWS ANOTHER CELL/LINE EVOLUTION MOVING
THROUGH NORTHERN IL AND SOUTHERN WI THIS EVENING.
PREV DISCUSSION... /ISSUED 1043 AM CDT THU MAY 30 2013/
UPDATE...
WE ARE RAMPING UP THE SEVERE THREAT FOR SOUTH CENTRAL WI FOR THIS
AFTERNOON. THERE IS A HIGH PROBABILITY OF STRONG THUNDERSTORMS IN
THE UPPER MIDWEST...AND A GOOD CHANCE OF SEVERE WINDS IN SOUTH
CENTRAL WI. SOUTHERN WISCONSIN IS BACK IN THE SLIGHT RISK FOR SEVERE
WEATHER AREA TODAY/TONIGHT.
A STRONG SHORTWAVE CURRENTLY OVER OKLAHOMA WILL BE SWINGING UP INTO
IOWA AROUND 21Z THIS AFTERNOON. THERE IS A WEAKER SHORTWAVE OUT
AHEAD OF THAT WHICH WILL GET INTO EASTERN IOWA/SOUTHERN WI JUST
AFTER 18Z. THE LEADING SHORTWAVE WILL NEED TO BE WATCHED FOR EARLY
AFTERNOON CONVECTION OVER SOUTH CENTRAL WI. THE MAIN STRONG
SHORTWAVE WILL LIKELY DRIVE A THUNDERSTORM COMPLEX ACROSS ALL OF
SOUTHERN WISCONSIN LATE AFTERNOON EARLY EVENING.
THE SPC STORM SCALE ENSEMBLE OF OPPORTUNITY SHOWS A TONGUE OF HIGH
PROBABILITY OF UPDRAFT HELICITY VALUES GREATER THAN 25 M2/S2
STRETCHING INTO CENTRAL WISCONSIN. THE HIGHEST VALUES ARE FOCUSED
OVER THE PLAINS AND EASTERN IOWA...BUT THE 60-70 PERCENTS OVER SOUTH
CENTRAL WI ARE STILL VERY IMPRESSIVE. THE CRAVEN-WIEDENFELD
AGGREGATE SEVERE PARAMETER WHICH COMPILES INGREDIENTS FOR SEVERE
THUNDERSTORMS AND GIVES A SCORE/PERCENTAGE CONTINUES TO HAVE VERY
HIGH VALUES IN SOUTHWEST AND SOUTH CENTRAL WI IN THE 75-82 PERCENT
RANGE...WITH RUC13 VALUES EVEN HIGHER. IN ADDITION...CIPS ANALOGS
SHOW A HISTORY OF SEVERE WEATHER OCCURRING WITH THE CURRENT SYNOPTIC
PATTERN.
MODE OF CONVECTION IS STILL IN QUESTION. THE MOST LIKELY MODE IS
LINES OF STORMS PRODUCING BOWING SEGMENTS. THE SHEAR IS RELATIVELY
WEAK OVER THE REGION AND UNIDIRECTIONAL. IT IS FORECAST TO
STRENGTHEN THROUGH THE AFTERNOON...AS WILL LOW LEVEL WIND
SHEAR...WHICH WOULD HELP CELLS REMAIN MORE DISCRETE OR HAVE JUST
SMALL BOWING LINE SEGMENTS. TORNADO DEVELOPMENT WILL BE POSSIBLE
GIVEN LOW LCL AND HIGH LOW LEVEL SHEAR. THE WIDESPREAD CUMULUS
CLOUDS THAT DEVELOPED THIS MORNING WILL ACTUALLY HELP THE SEVERE
SITUATION BY KEEPING US FROM MIXING OUT TOO MUCH AND ALLOWING THE
DEWPOINTS TO REMAIN HIGH.
THE 13Z HRRR IS SHOWING A MORE DISCRETE MODE OVER SOUTHERN WI EARLY
THIS AFTERNOON...WITH A SQUALL LINE/MCS DEVELOPING WITH THE BIGGER
VORT MAX LATE THIS AFTERNOON/EVENING. THE QUAD CITIES NWS OFFICE
WILL BE DOING AN 18Z UPPER AIR SOUNDING TO ALLOW US TO BETTER ASSESS
THE SEVERE POTENTIAL.
AVIATION/18Z TAFS/...
EXPECT GUSTS BETWEEN 25 AND 30 KTS TO LAST THROUGH MOST OF THE DAY.
MVFR BROKEN CUMULUS CLOUDS DEVELOPED AND WILL GRADUALLY LIFT TO VFR
BY 18Z.
STORMS WILL DEVELOP OVER EASTERN IOWA AND MOVE NORTHEAST INTO
SOUTHERN WISCONSIN EARLY THIS AFTERNOON. MADISON WILL HAVE THE BEST
CHANCE FOR EARLIER THUNDERSTORMS. SOME MAY BE SEVERE. THEN ANOTHER
ROUND OF THUNDERSTORMS IS EXPECTED LATE AFTERNOON/EARLY EVENING AND
THESE WILL LIKELY SPREAD ALL THE WAY INTO SOUTHEAST WI.
STRAIGHT-LINE WINDS ARE THE MAIN SEVERE WEATHER THREAT.
MARINE...
GUSTY SOUTH WINDS DUE TO MIXING OVER THE LAND WILL AFFECT SHORELINE
NEARSHORE AREAS ALL DAY TODAY. MAY NEED A SMALL CRAFT ADVISORY TO
HANDLE THIS. WINDS WILL BE LESS GUSTY TOWARD THE OPEN WATERS.
HOWEVER...THE TIGHT PRESSURE GRADIENT OVER THE LAKE WILL ALLOW
SUSTAINED WINDS TO BE IN THE 15 TO 20 KNOT RANGE TODAY. STABLE AIR
DOWN AT LAKE LEVEL WILL KEEP WAVES FROM RESPONDING TOO MUCH TO THE
GUSTY WINDS.
PREV DISCUSSION... /ISSUED 449 AM CDT THU MAY 30 2013/
TODAY AND TONIGHT...FORECAST CONFIDENCE...MEDIUM
CONVECTION HAS LIFTED NORTH OF THE FORECAST AREA WITH SHORT WAVE/MCV
AND ADDITIONAL SUPPORT FROM RIGHT ENTRANCE REGION OF UPPER JET.
MODELS DAMPEN FIRST SHORT WAVE CURRENTLY DRIVING SRN PLAINS
CONVECTION AND FOCUS ON WAVE NEAR THE PANHANDLE REGION THAT WILL
SWING UP TOWARDS IA/NEB BY 00Z FRI AS 500 MB LOW GOES NEGATIVE-TILT.
WITH COMBINATION OF CENTRAL PLAINS SHORT WAVE/MCV AND 850 MB JET MAX
AND INSTABILITY ON AREA SOUNDINGS...THOUGH CAPE VALUES MAY BE A BIT
TOO HIGH DUE TO GENEROUS SURFACE DEW POINTS...WILL FOLLOW CONSENSUS
BLEND POPS AND INCREASE PRECIPITATION CHANCES RAPIDLY THROUGH THE
MORNING. HIGH POPS CONTINUE INTO THE EVENING...THEN TAPER OFF AS
FORCING WITH WAVE AND LOW-LEVEL JET MAX LIFT OFF TOP THE NORTHEAST.
WILL HAVE TO WATCH WESTERN COUNTIES OF S CENTRAL WI FOR FLASH
FLOODING POTENTIAL AFTER RECEIVING HEAVY RAIN WITH THE CONVECTION
WEDNESDAY EVENING.
LATEST SPC DAY 1 OUTLOOK HAS SHIFTED SLIGHT RISK TO THE SOUTHWEST
OUT OF OF WISCONSIN AS FAVORABLE SHEAR FOR ROTATING CELLS LESSENS
THROUGH THE DAY...BUT AN ISOLATED WIND/HAIL MAKER NOT OUT OF THE
QUESTION.
FRIDAY AND SATURDAY...FORECAST CONFIDENCE...MEDIUM
SOUTHERN WISCONSIN WILL REMAIN IN THE WARM SECTOR FRIDAY AS LOW
PRESSURE OVER NORTH DAKOTA AND MINNESOTA REMAINS NEARLY
STATIONARY. SHOWERS AND STORMS ARE THUS LIKELY ONCE AGAIN. THOUGH
THE BEST LOW LEVEL FLOW WILL BE TO THE SOUTH AND EAST...STRONGER
STORMS ARE NOT OUT OF THE QUESTION WITH SIMILAR UP TO 1000 J/KG OF
SURFACE BASED CAPE...AND WIND SHEAR ACTUALLY A BIT HIGHER THAN
PREVIOUS DAYS. LOOKS LIKE BEST CHANCE FOR SHOWERS AND STORMS WILL
BE LATE AFTERNOON INTO THE NIGHT...AS ANOTHER SHORTWAVE ROTATES
THROUGH THE AREA.
TEMPERATURES WILL BE SIMILAR FRIDAY AS THURSDAY...PUSHING OR
REACHING 80 MOST PLACES. PROBABLY A BIT TRICKY NEAR THE LAKE AGAIN
UNDER SOUTHERLY WINDS...BUT MOST AREAS SHOULD SEE THE WARMER TEMPS.
WEAKENING LOW PRESSURE WILL FINALLY DRAG A COLD FRONT THROUGH
SOUTHERN WISCONSIN BY SATURDAY NIGHT. MODELS HAVE SLOWED A BIT WITH
THE FRONT...SO TEMPS AND POPS HAVE TRENDED IT BIT HIGHER WITH
SOUTHERN WISCONSIN REMAINING IN THE WARM SECTOR A BIT LONGER.
SUNDAY THROUGH WEDNESDAY...FORECAST CONFIDENCE...MEDIUM
MAIN UPPER LEVEL TROUGH AXIS WILL MOVE THROUGH SUNDAY...POSSIBLY
BRINGING A FEW SHOWERS. COOLER AIR IS EXPECTED TO ARRIVE WITH THE
SHORTWAVE...WITH TEMPERATURES FALLING BACK BELOW NORMAL.
SHOULD BE PLEASANT MONDAY UNDER HIGH PRESSURE...WITH A CHANCE FOR
SHOWERS AND STORMS RETURNING LATER TUESDAY INTO WEDNESDAY. HIGHS
WILL LIKELY REMAIN A FEW DEGREES BELOW NORMAL THROUGH THE FIRST HALF
OF NEXT WEEK.
AVIATION/12Z TAFS/...
WILL KEEP WIND SHEAR IN ALL OF THE TAFS...WITH WIND PROFILERS
PICKING UP 35 TO 40 KT WINDS BETWEEN 1500-2000 FT...UNTIL SURFACE
WINDS INCREASE WITH MIXING AFTER DAYBREAK. EXPECT SOUTHERLY GUSTS
BETWEEN 25 AND 30 KTS BY MID-MORNING AND LASTING THROUGH MOST OF
THE DAY.
INCREASED LOW-LEVEL MOISTURE AND COOLING EFFECTS OF LAST NIGHT/S
STORMS HAVE PRODUCED FOG AT KMSN WHICH SHOULD LIFT WITH INCREASING
WINDS AFTER SUNRISE. OTHERWISE VFR CONDITIONS THROUGH MOST OF THE DAY.
WHILE EXACT TIMING IS QUESTIONABLE...WEAK UPPER DISTURBANCE AND
ANOTHER LOW-LEVEL JET MAX APPROACHING THE UPPER MIDWEST WILL BRING
INCREASING CHANCES FOR THUNDERSTORMS. BEST CHANCES STAY WEST OF
KMSN UNTIL MID-LATE MORNING...THEN SPREAD EAST AND INCREASE THROUGH
THE AFTERNOON. SHOWERS AND STORMS MOST LIKELY FROM LATE AFTERNOON
THROUGH THE EVENING BRINGING MVFR CIGS/VSBYS...POSSIBLY DROPPING
TO IFR WITH HEAVY DOWNPOURS OF RAIN. WILL THEN KEEP MVFR
CONDITIONS THROUGH THE REMAINDER OF THE FORECAST.
MARINE...
SOUTH WINDS WILL INCREASE RAPIDLY AFTER SUNRISE...WITH
GUSTS TO 20 KNOTS BY MID TO LATE MORNING. PREVAILING WINDS HOLD JUST
BELOW SMALL CRAFT CRITERIA...THOUGH THERE WILL BE A FEW GUSTS TO
25 KNOTS. HAVE ADDED A CAUTIONARY STATEMENT FOR SMALL CRAFT IN THE
NEARSHORE FORECAST AND IN THE HAZARDOUS WEATHER OUTLOOK FOR TODAY.
EXPECT THUNDERSTORM CHANCES TO INCREASE THROUGH THE LATE MORNING
AND AFTERNOON...BECOMING MOST LIKELY THIS EVENING. WHILE THE STORMS
ARE EXPECTED TO STAY BELOW SEVERE LEVELS...GUSTY WINDS...SMALL
HAIL AND VISIBILITY-REDUCING HEAVY RAINS ARE POSSIBLE.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...NONE.
&&
$$
UPDATE...CRAVEN
TODAY/TONIGHT AND AVIATION/MARINE...MRC
FRIDAY THROUGH WEDNESDAY...HENTZ
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1225 PM CDT THU MAY 30 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 333 AM CDT THU MAY 30 2013
CURRENTLY AS OF 0830Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT
ANALYSIS SHOWED UPPER TROUGHING FROM THE NORTHEAST PACIFIC INTO THE
NORTHERN ROCKIES WITH AN UPPER LOW IN NORTHEAST WYOMING...WHILE
DOWNSTREAM RIDGING WAS PRESENT ACROSS THE EASTERN U.S.. ALSO TO NOTE
ON WATER VAPOR IS A FAIRLY POTENT SHORTWAVE OVER THE TEXAS AND
OKLAHOMA PANHANDLES IN THE BASE OF THIS TROUGHING. NEARLY
UNIDIRECTIONAL SOUTH TO SOUTHWEST FLOW EXISTED BETWEEN THE TROUGHING
AND RIDGING... WITH SOME VERY STRONG WINDS AT 850MB. VWP AND
PROFILER DATA SHOWED SPEEDS OF 50-65 KT FROM CENTRAL OKLAHOMA INTO
SOUTHERN MINNESOTA. THESE WINDS WERE TRANSPORTING COPIOUS AMOUNTS OF
MOISTURE NORTHWARD...NOTED BY PRECIPITABLE WATER VALUES OF 1.5-1.75
INCHES OR 150-180 PERCENT OF NORMAL. NUMEROUS SHORTWAVES...SOME
CONVECTIVELY INDUCED...RIDING THROUGH THE MID LEVEL FLOW HAS BEEN
INTERACTING WITH THE MORE SUMMER-LIKE AIRMASS TO CONTINUE TO PRODUCE
SCATTERED CLUSTERS OF SHOWERS AND THUNDERSTORMS. MUCH OF THE
FORECAST AREA LIES IN THE WARM SECTOR OF A LOW PRESSURE SYSTEM BACK
IN THE DAKOTAS. MAIN WARM FRONT HAS LIFTED INTO NORTHERN WISCONSIN
WHILE THE COLD FRONT IS WELL BACK TO THE WEST IN CENTRAL SOUTH
DAKOTA.
MODELS ARE IN GOOD AGREEMENT ON THE SYNOPTICS THROUGH TONIGHT...
INDICATING THAT THE UPPER TROUGHING FROM WYOMING INTO THE TEXAS
PANHANDLE WILL SHIFT EAST NORTHEAST INTO THE FORECAST AREA BY 06Z
TONIGHT. THERE ARE SOME DECENT 500MB HEIGHT FALLS BETWEEN 18Z-06Z
OVER THE FORECAST AREA...ON THE ORDER OF 60-90 METERS. THE DPVA FROM
THE APPROACH OF THIS UPPER TROUGH...AS WELL AS VARIOUS SHORTWAVES
AND CONVECTIVELY INDUCED SHORTWAVES AHEAD OF IT...SUGGESTS PLENTY OF
FORCING FOR CONVECTION. MODELS HAVE SHOWN THIS FOR MANY DAYS AS
WELL. THIS FORCING MAY MAKE IT HARD TO BUILD A LOT OF INSTABILITY...
COMPARED TO YESTERDAY WHERE WE HAD PLENTY OF SUNSHINE BEFORE
CONVECTION ERUPTED. RAP/NAM/GFS SOUNDINGS ALL SUGGEST ANY 0-1 MLCIN
FROM NOCTURNAL INFLUENCES BEING NEARLY COMPLETELY GONE BY 15Z.
THEREFORE IT IS CONCEIVABLE FOR CONVECTION TO FIRE SHORTLY
THEREAFTER WHEN 0-1 MLCAPE IS ONLY AT 800-1500 J/KG. HRRR/RAP MODELS
SHOW CONVECTION FIRING IN THAT 15-16Z WINDOW...IN AGREEMENT WITH THE
ABOVE ANALYSIS. THE CONVECTION MAY STABILIZE THINGS BRIEFLY...BUT
PERSISTENT HEATING THROUGH THE DAY COMBINED WITH SOUTHERLY WARM
ADVECTION OF INSTABILITY SHOULD PROVIDE FUEL TO CONTINUE PERIODS OF
CONVECTION THROUGH THE DAY AND INTO THE EVENING. PASSAGE OF THE
UPPER TROUGH AND NOCTURNAL COOLING SHOULD ALLOW CONVECTION TO
SUBSIDE AFTER MIDNIGHT.
REGARDING SEVERE POTENTIAL...THE LIMITATION OF BUILDING A LOT OF
CAPE IS A HINDRANCE. 0-6KM SHEAR FROM THE 30.00Z NAM/GFS IS
GENERALLY PROGGED AT 25-30 KT THROUGH THE DAY...FAVORING FOR MORE OF
A MULTI-CELL SITUATION. WITH INSTABILITY STRUGGLING...NOT THINKING
MUCH IN THE WAY FOR SEVERE HAIL. BULK OF THE AFOREMENTIONED 0-6KM
SHEAR IS IN THE 0-3KM LAYER...AND COMBINED WITH 850MB WINDS PROGGED
IN THE AFTERNOON AND EVENING OF 45-50 KT DOES BRING UP A CONCERN FOR
THE STORMS TO PRODUCE STRONG TO DAMAGING WIND GUSTS. 0-1KM SHEAR IS
QUITE HIGH AS WELL FOR THE AFTERNOON AND EVENING...SIMILAR TO 0-3KM
OF 25-30KT...SO WE MAY WANT TO WATCH FOR POSSIBLE TORNADOES TOO.
THIS WOULD BE ESPECIALLY TRUE ALONG ANY CONVECTIVE OUTFLOW BOUNDARY
AND/OR IF WE CAN GET MORE DAYTIME HEATING THAN EXPECTED.
ON THE FLOODING FRONT...MORE INFORMATION CAN BE FOUND IN THE
HYDROLOGY SECTION BELOW. BRIEFLY...THE PATTERN TODAY INTO THIS
EVENING IS VERY FAVORABLE FOR STORMS TO TRAIN ACROSS THE SAME AREAS
AS THEY MARCH SOUTH TO NORTH. WITH PRECIPITABLE WATER VALUES STAYING
UP IN THE 1.5-1.75 INCH RANGE ANY STORM CAN PRODUCE HEAVY RAIN. WITH
GROUNDS ALREADY SATURATED...FLASH FLOODING IS CERTAINLY POSSIBLE...
ESPECIALLY SOUTH OF I-90 WHICH WAS REALLY IMPACTED FROM YESTERDAY
INTO LAST NIGHT.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 333 AM CDT THU MAY 30 2013
LOW PRESSURE OVER THE EASTERN DAKOTAS PUSHES SOUTHEAST LATE FRIDAY
MORNING INTO FRIDAY AFTERNOON DRIVING THE FRONT ACROSS THE FORECAST
AREA. DEPENDING ON THE TIMING OF THIS FRONT...SEVERE WEATHER POSSIBLE
ON FRIDAY. FORECAST MODELS ARE IN REASONABLE AGREEMENT...SHOWING
0-3 KM MUCAPE VALUES CLIMBING TO 2000 TO 3000 J/KG. SHEAR IS ALSO
RAMPING UP LATE FRIDAY MORNING INTO FRIDAY AFTERNOON WITH 0-6 KM
BULK SHEAR INCREASING TO 45 TO 55 KTS. THE HIGHEST INSTABILITY
APPEARS TO BE OVER FAR NORTHEAST IOWA AND INTO EXTREME SOUTHWEST
WISCONSIN. WILL HAVE TO KEEP A VERY CLOSE WATCH ON THIS OVER THE
NEXT FEW MODEL RUNS. AT THIS TIME...LARGE HAIL AND DAMAGING WINDS
APPEAR TO BE THE MAIN HAZARDS FROM THESE STORMS. BUT AGAIN...THE
SEVERE THREAT AREA WILL DEPEND ON WHERE THE BOUNDARY IS LOCATED
LATE FRIDAY MORNING INTO FRIDAY AFTERNOON AND HOW MUCH SURFACE
HEATING IS REALIZED. A DRY SLOT PUSHES INTO THE FORECAST AREA LATE
FRIDAY NIGHT AS THE LOW PUSHES EAST INTO THE WESTERN GREAT LAKES.
THERE SHOULD BE A DRY PERIOD AS THE LOW MOVES IN...BUT THEN
SHOWERS AND ISOLATED THUNDERSTORMS WILL DEVELOP ON SATURDAY AS THE
LOW SLIDES ACROSS THE REGION. AN UNSEASONABLY COOL AIRMASS MOVES
INTO REGION ON SUNDAY. 850 MB TEMPERATURES FALL TO 0 C OVER
NORTHERN WISCONSIN AND TO AROUND 2 C OVER NORTHEAST IOWA. THIS
WILL SET THE STAGE FOR A CHILLY NIGHT ACROSS THE AREA SUNDAY NIGHT
INTO EARLY MONDAY MORNING. ECMWF 850 MB TEMPERATURE STANDARDIZED
ANOMALIES FALL TO AROUND -1.5...INDICATIVE OF AN ANOMALOUSLY COLD
AIRMASS. TEMPERATURES WILL PLUMMET INTO THE UPPER 30S OVER FAR
NORTHERN WISCONSIN. WILL HAVE TO KEEP A VERY CLOSE WATCH ON LOWS OVER
NORTH CENTRAL AND CENTRAL WISCONSIN WHERE TYPICAL COLD SPOTS SUCH
AS SPARTA AND BLACK RIVER FALLS COULD SEE LOWS DIP INTO THE UPPER
30S...LEADING TO FROST FORMATION. COOL HIGH PRESSURE REMAINS OVER
THE REGION THROUGH TUESDAY...WITH HIGHS ONLY IN THE 60S. HIGH
PRESSURE PUSHES EAST OF THE REGION LATE TUESDAY INTO WEDNESDAY AS
A TROUGH DIGS INTO THE DAKOTAS. SOUTHERLY FLOW DEVELOPS OVER THE
AREA HELPING TO USHER IN WARMER TEMPERATURES. THE TROUGH WILL MOVE
INTO THE FORECAST AREA LATE TUESDAY NIGHT THROUGH WEDNESDAY
BRINGING CHANCES FOR SHOWERS AND THUNDERSTORMS TO THE AREA.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1225 PM CDT THU MAY 30 2013
FORECAST THIS PERIOD REMAINS DIFFICULT...ESPECIALLY THIS AFTERNOON
AND EVENING. ANOTHER ROUND OF MORE WIDESPREAD SHRA/TSRA EXPECTED TO
SPREAD ACROSS THE TAF SITES THIS AFTERNOON/EVENING WITH PERIOD OF
MVFR CIGS AND IFR/MVFR VSBYS IN STRONGER STORM CORES. GENERALLY LEFT
TSRA MENTION IN TAFS FOR THIS AFTERNOON AS VCTS AND CB DUE TO
UNCERTAINTIES OF THE TIMING AND TSRA PASSING OVER A TAF SITE. PLAN
ON TAF UPDATES AS CONVECTION MODE/TIMING BECOME CLEARER THRU THE
AFTERNOON.
TIGHT PRESSURE GRADIENT REMAINS OVER THE AREA THIS AFTERNOON FOR
SOUTH WINDS 15-20KT G25-30KTS. GRADIENT RELAXES A BIT TONIGHT BUT
WIND LOOK TO REMAIN SOUTH 10-15KTS...FOR GOOD BOUNDARY LAYER
STIRRING/MIXING TO LIMIT BR FORMATION. ONCE THE MID LEVEL TROUGH
AXIS PASSES TONIGHT...SFC TO MID LEVEL FLOW SWINGS A BIT MORE
SOUTHWEST...BRINGING SOME SLIGHTLY DRIER AIR INTO THE AREA.
GENERALLY SCT030 CLOUDS EXPECTED LATER TONIGHT/FRI MORNING BEHIND
THIS PASSING FEATURE.
&&
.HYDROLOGY...TODAY AND TONIGHT
ISSUED AT 333 AM CDT THU MAY 30 2013
HEAVY RAIN FELL ACROSS THE AREA WEDNESDAY AFTERNOON AND EVENING
WITH RAINFALL AMOUNTS OF 2 TO 3 INCHES REPORTED ACROSS PORTIONS OF
NORTHEAST IOWA...SOUTHEAST MINNESOTA AND SOUTHWEST
WISCONSIN...WITH LOCALLY HIGHER AMOUNTS OF 4 INCHES REPORTED. AN
ADDITIONAL 1 TO 2 INCHES OF RAIN IS EXPECTED ACROSS THE AREA
TODAY THROUGH THIS EVENING...WHICH COULD LEAD TO FLASH FLOODING.
IT WILL NOT TAKE MUCH RAIN OVER THE SATURATED SOILS TO CREATE
FLOODING ISSUES. ALSO...AREA RIVERS WILL SEE RISES AND POSSIBLE
FLOODING WITH ANY ADDITIONAL RAINFALL RECEIVED. HAVE EXPANDED THE
FLASH FLOOD WATCH NORTHWARD...INCLUDING AREAS ALONG AND SOUTHWEST
OF INTERSTATE 94 CORRIDOR EXCLUDING JUNEAU COUNTY
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR WIZ032>034-041-042-
053>055-061.
MN...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR MNZ079-086>088-
094>096.
IA...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR IAZ008>011-018-019-
029-030.
&&
$$
SHORT TERM...AJ/WETENKAMP
LONG TERM....WETENKAMP
AVIATION.....RRS
HYDROLOGY....WETENKAMP
AREA FORECAST DISCUSSION...UPDATED
NWS MILWAUKEE/SULLIVAN WI
1043 AM CDT THU MAY 30 2013
.UPDATE...
WE ARE RAMPING UP THE SEVERE THREAT FOR SOUTH CENTRAL WI FOR THIS
AFTERNOON. THERE IS A HIGH PROBABILITY OF STRONG THUNDERSTORMS IN
THE UPPER MIDWEST...AND A GOOD CHANCE OF SEVERE WINDS IN SOUTH
CENTRAL WI. SOUTHERN WISCONSIN IS BACK IN THE SLIGHT RISK FOR SEVERE
WEATHER AREA TODAY/TONIGHT.
A STRONG SHORTWAVE CURRENTLY OVER OKLAHOMA WILL BE SWINGING UP INTO
IOWA AROUND 21Z THIS AFTERNOON. THERE IS A WEAKER SHORTWAVE OUT
AHEAD OF THAT WHICH WILL GET INTO EASTERN IOWA/SOUTHERN WI JUST
AFTER 18Z. THE LEADING SHORTWAVE WILL NEED TO BE WATCHED FOR EARLY
AFTERNOON CONVECTION OVER SOUTH CENTRAL WI. THE MAIN STRONG
SHORTWAVE WILL LIKELY DRIVE A THUNDERSTORM COMPLEX ACROSS ALL OF
SOUTHERN WISCONSIN LATE AFTERNOON EARLY EVENING.
THE SPC STORM SCALE ENSEMBLE OF OPPORTUNITY SHOWS A TONGUE OF HIGH
PROBABILITY OF UPDRAFT HELICITY VALUES GREATER THAN 25 M2/S2
STRETCHING INTO CENTRAL WISCONSIN. THE HIGHEST VALUES ARE FOCUSED
OVER THE PLAINS AND EASTERN IOWA...BUT THE 60-70 PERCENTS OVER SOUTH
CENTRAL WI ARE STILL VERY IMPRESSIVE. THE CRAVEN-WIEDENFELD
AGGREGATE SEVERE PARAMETER WHICH COMPILES INGREDIENTS FOR SEVERE
THUNDERSTORMS AND GIVES A SCORE/PERCENTAGE CONTINUES TO HAVE VERY
HIGH VALUES IN SOUTHWEST AND SOUTH CENTRAL WI IN THE 75-82 PERCENT
RANGE...WITH RUC13 VALUES EVEN HIGHER. IN ADDITION...CIPS ANALOGS
SHOW A HISTORY OF SEVERE WEATHER OCCURRING WITH THE CURRENT SYNOPTIC
PATTERN.
MODE OF CONVECTION IS STILL IN QUESTION. THE MOST LIKELY MODE IS
LINES OF STORMS PRODUCING BOWING SEGMENTS. THE SHEAR IS RELATIVELY
WEAK OVER THE REGION AND UNIDIRECTIONAL. IT IS FORECAST TO
STRENGTHEN THROUGH THE AFTERNOON...AS WILL LOW LEVEL WIND
SHEAR...WHICH WOULD HELP CELLS REMAIN MORE DISCRETE OR HAVE JUST
SMALL BOWING LINE SEGMENTS. TORNADO DEVELOPMENT WILL BE POSSIBLE
GIVEN LOW LCL AND HIGH LOW LEVEL SHEAR. THE WIDESPREAD CUMULUS
CLOUDS THAT DEVELOPED THIS MORNING WILL ACTUALLY HELP THE SEVERE
SITUATION BY KEEPING US FROM MIXING OUT TOO MUCH AND ALLOWING THE
DEWPOINTS TO REMAIN HIGH.
THE 13Z HRRR IS SHOWING A MORE DISCRETE MODE OVER SOUTHERN WI EARLY
THIS AFTERNOON...WITH A SQUALL LINE/MCS DEVELOPING WITH THE BIGGER
VORT MAX LATE THIS AFTERNOON/EVENING. THE QUAD CITIES NWS OFFICE
WILL BE DOING AN 18Z UPPER AIR SOUNDING TO ALLOW US TO BETTER ASSESS
THE SEVERE POTENTIAL.
&&
.AVIATION/18Z TAFS/...
EXPECT GUSTS BETWEEN 25 AND 30 KTS TO LAST THROUGH MOST OF THE DAY.
MVFR BROKEN CUMULUS CLOUDS DEVELOPED AND WILL GRADUALLY LIFT TO VFR
BY 18Z.
STORMS WILL DEVELOP OVER EASTERN IOWA AND MOVE NORTHEAST INTO
SOUTHERN WISCONSIN EARLY THIS AFTERNOON. MADISON WILL HAVE THE BEST
CHANCE FOR EARLIER THUNDERSTORMS. SOME MAY BE SEVERE. THEN ANOTHER
ROUND OF THUNDERSTORMS IS EXPECTED LATE AFTERNOON/EARLY EVENING AND
THESE WILL LIKELY SPREAD ALL THE WAY INTO SOUTHEAST WI.
STRAIGHT-LINE WINDS ARE THE MAIN SEVERE WEATHER THREAT.
&&
.MARINE...
GUSTY SOUTH WINDS DUE TO MIXING OVER THE LAND WILL AFFECT SHORELINE
NEARSHORE AREAS ALL DAY TODAY. MAY NEED A SMALL CRAFT ADVISORY TO
HANDLE THIS. WINDS WILL BE LESS GUSTY TOWARD THE OPEN WATERS.
HOWEVER...THE TIGHT PRESSURE GRADIENT OVER THE LAKE WILL ALLOW
SUSTAINED WINDS TO BE IN THE 15 TO 20 KNOT RANGE TODAY. STABLE AIR
DOWN AT LAKE LEVEL WILL KEEP WAVES FROM RESPONDING TOO MUCH TO THE
GUSTY WINDS.
&&
.PREV DISCUSSION... /ISSUED 449 AM CDT THU MAY 30 2013/
TODAY AND TONIGHT...FORECAST CONFIDENCE...MEDIUM
CONVECTION HAS LIFTED NORTH OF THE FORECAST AREA WITH SHORT WAVE/MCV
AND ADDITIONAL SUPPORT FROM RIGHT ENTRANCE REGION OF UPPER JET.
MODELS DAMPEN FIRST SHORT WAVE CURRENTLY DRIVING SRN PLAINS
CONVECTION AND FOCUS ON WAVE NEAR THE PANHANDLE REGION THAT WILL
SWING UP TOWARDS IA/NEB BY 00Z FRI AS 500 MB LOW GOES NEGATIVE-TILT.
WITH COMBINATION OF CENTRAL PLAINS SHORT WAVE/MCV AND 850 MB JET MAX
AND INSTABILITY ON AREA SOUNDINGS...THOUGH CAPE VALUES MAY BE A BIT
TOO HIGH DUE TO GENEROUS SURFACE DEW POINTS...WILL FOLLOW CONSENSUS
BLEND POPS AND INCREASE PRECIPITATION CHANCES RAPIDLY THROUGH THE
MORNING. HIGH POPS CONTINUE INTO THE EVENING...THEN TAPER OFF AS
FORCING WITH WAVE AND LOW-LEVEL JET MAX LIFT OFF TOP THE NORTHEAST.
WILL HAVE TO WATCH WESTERN COUNTIES OF S CENTRAL WI FOR FLASH
FLOODING POTENTIAL AFTER RECEIVING HEAVY RAIN WITH THE CONVECTION
WEDNESDAY EVENING.
LATEST SPC DAY 1 OUTLOOK HAS SHIFTED SLIGHT RISK TO THE SOUTHWEST
OUT OF OF WISCONSIN AS FAVORABLE SHEAR FOR ROTATING CELLS LESSENS
THROUGH THE DAY...BUT AN ISOLATED WIND/HAIL MAKER NOT OUT OF THE
QUESTION.
FRIDAY AND SATURDAY...FORECAST CONFIDENCE...MEDIUM
SOUTHERN WISCONSIN WILL REMAIN IN THE WARM SECTOR FRIDAY AS LOW
PRESSURE OVER NORTH DAKOTA AND MINNESOTA REMAINS NEARLY
STATIONARY. SHOWERS AND STORMS ARE THUS LIKELY ONCE AGAIN. THOUGH
THE BEST LOW LEVEL FLOW WILL BE TO THE SOUTH AND EAST...STRONGER
STORMS ARE NOT OUT OF THE QUESTION WITH SIMILAR UP TO 1000 J/KG OF
SURFACE BASED CAPE...AND WIND SHEAR ACTUALLY A BIT HIGHER THAN
PREVIOUS DAYS. LOOKS LIKE BEST CHANCE FOR SHOWERS AND STORMS WILL
BE LATE AFTERNOON INTO THE NIGHT...AS ANOTHER SHORTWAVE ROTATES
THROUGH THE AREA.
TEMPERATURES WILL BE SIMILAR FRIDAY AS THURSDAY...PUSHING OR
REACHING 80 MOST PLACES. PROBABLY A BIT TRICKY NEAR THE LAKE AGAIN
UNDER SOUTHERLY WINDS...BUT MOST AREAS SHOULD SEE THE WARMER TEMPS.
WEAKENING LOW PRESSURE WILL FINALLY DRAG A COLD FRONT THROUGH
SOUTHERN WISCONSIN BY SATURDAY NIGHT. MODELS HAVE SLOWED A BIT WITH
THE FRONT...SO TEMPS AND POPS HAVE TRENDED IT BIT HIGHER WITH
SOUTHERN WISCONSIN REMAINING IN THE WARM SECTOR A BIT LONGER.
SUNDAY THROUGH WEDNESDAY...FORECAST CONFIDENCE...MEDIUM
MAIN UPPER LEVEL TROUGH AXIS WILL MOVE THROUGH SUNDAY...POSSIBLY
BRINGING A FEW SHOWERS. COOLER AIR IS EXPECTED TO ARRIVE WITH THE
SHORTWAVE...WITH TEMPERATURES FALLING BACK BELOW NORMAL.
SHOULD BE PLEASANT MONDAY UNDER HIGH PRESSURE...WITH A CHANCE FOR
SHOWERS AND STORMS RETURNING LATER TUESDAY INTO WEDNESDAY. HIGHS
WILL LIKELY REMAIN A FEW DEGREES BELOW NORMAL THROUGH THE FIRST HALF
OF NEXT WEEK.
AVIATION/12Z TAFS/...
WILL KEEP WIND SHEAR IN ALL OF THE TAFS...WITH WIND PROFILERS
PICKING UP 35 TO 40 KT WINDS BETWEEN 1500-2000 FT...UNTIL SURFACE
WINDS INCREASE WITH MIXING AFTER DAYBREAK. EXPECT SOUTHERLY GUSTS
BETWEEN 25 AND 30 KTS BY MID-MORNING AND LASTING THROUGH MOST OF
THE DAY.
INCREASED LOW-LEVEL MOISTURE AND COOLING EFFECTS OF LAST NIGHT/S
STORMS HAVE PRODUCED FOG AT KMSN WHICH SHOULD LIFT WITH INCREASING
WINDS AFTER SUNRISE. OTHERWISE VFR CONDITIONS THROUGH MOST OF THE DAY.
WHILE EXACT TIMING IS QUESTIONABLE...WEAK UPPER DISTURBANCE AND
ANOTHER LOW-LEVEL JET MAX APPROACHING THE UPPER MIDWEST WILL BRING
INCREASING CHANCES FOR THUNDERSTORMS. BEST CHANCES STAY WEST OF
KMSN UNTIL MID-LATE MORNING...THEN SPREAD EAST AND INCREASE THROUGH
THE AFTERNOON. SHOWERS AND STORMS MOST LIKELY FROM LATE AFTERNOON
THROUGH THE EVENING BRINGING MVFR CIGS/VSBYS...POSSIBLY DROPPING
TO IFR WITH HEAVY DOWNPOURS OF RAIN. WILL THEN KEEP MVFR
CONDITIONS THROUGH THE REMAINDER OF THE FORECAST.
MARINE...
SOUTH WINDS WILL INCREASE RAPIDLY AFTER SUNRISE...WITH
GUSTS TO 20 KNOTS BY MID TO LATE MORNING. PREVAILING WINDS HOLD JUST
BELOW SMALL CRAFT CRITERIA...THOUGH THERE WILL BE A FEW GUSTS TO
25 KNOTS. HAVE ADDED A CAUTIONARY STATEMENT FOR SMALL CRAFT IN THE
NEARSHORE FORECAST AND IN THE HAZARDOUS WEATHER OUTLOOK FOR TODAY.
EXPECT THUNDERSTORM CHANCES TO INCREASE THROUGH THE LATE MORNING
AND AFTERNOON...BECOMING MOST LIKELY THIS EVENING. WHILE THE STORMS
ARE EXPECTED TO STAY BELOW SEVERE LEVELS...GUSTY WINDS...SMALL
HAIL AND VISIBILITY-REDUCING HEAVY RAINS ARE POSSIBLE.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...NONE.
&&
$$
UPDATE...MRC
TODAY/TONIGHT AND AVIATION/MARINE...REM
FRIDAY THROUGH WEDNESDAY...DDV
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
600 AM CDT THU MAY 30 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 333 AM CDT THU MAY 30 2013
CURRENTLY AS OF 0830Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT
ANALYSIS SHOWED UPPER TROUGHING FROM THE NORTHEAST PACIFIC INTO THE
NORTHERN ROCKIES WITH AN UPPER LOW IN NORTHEAST WYOMING...WHILE
DOWNSTREAM RIDGING WAS PRESENT ACROSS THE EASTERN U.S.. ALSO TO NOTE
ON WATER VAPOR IS A FAIRLY POTENT SHORTWAVE OVER THE TEXAS AND
OKLAHOMA PANHANDLES IN THE BASE OF THIS TROUGHING. NEARLY
UNIDIRECTIONAL SOUTH TO SOUTHWEST FLOW EXISTED BETWEEN THE TROUGHING
AND RIDGING... WITH SOME VERY STRONG WINDS AT 850MB. VWP AND
PROFILER DATA SHOWED SPEEDS OF 50-65 KT FROM CENTRAL OKLAHOMA INTO
SOUTHERN MINNESOTA. THESE WINDS WERE TRANSPORTING COPIOUS AMOUNTS OF
MOISTURE NORTHWARD...NOTED BY PRECIPITABLE WATER VALUES OF 1.5-1.75
INCHES OR 150-180 PERCENT OF NORMAL. NUMEROUS SHORTWAVES...SOME
CONVECTIVELY INDUCED...RIDING THROUGH THE MID LEVEL FLOW HAS BEEN
INTERACTING WITH THE MORE SUMMER-LIKE AIRMASS TO CONTINUE TO PRODUCE
SCATTERED CLUSTERS OF SHOWERS AND THUNDERSTORMS. MUCH OF THE
FORECAST AREA LIES IN THE WARM SECTOR OF A LOW PRESSURE SYSTEM BACK
IN THE DAKOTAS. MAIN WARM FRONT HAS LIFTED INTO NORTHERN WISCONSIN
WHILE THE COLD FRONT IS WELL BACK TO THE WEST IN CENTRAL SOUTH
DAKOTA.
MODELS ARE IN GOOD AGREEMENT ON THE SYNOPTICS THROUGH TONIGHT...
INDICATING THAT THE UPPER TROUGHING FROM WYOMING INTO THE TEXAS
PANHANDLE WILL SHIFT EAST NORTHEAST INTO THE FORECAST AREA BY 06Z
TONIGHT. THERE ARE SOME DECENT 500MB HEIGHT FALLS BETWEEN 18Z-06Z
OVER THE FORECAST AREA...ON THE ORDER OF 60-90 METERS. THE DPVA FROM
THE APPROACH OF THIS UPPER TROUGH...AS WELL AS VARIOUS SHORTWAVES
AND CONVECTIVELY INDUCED SHORTWAVES AHEAD OF IT...SUGGESTS PLENTY OF
FORCING FOR CONVECTION. MODELS HAVE SHOWN THIS FOR MANY DAYS AS
WELL. THIS FORCING MAY MAKE IT HARD TO BUILD A LOT OF INSTABILITY...
COMPARED TO YESTERDAY WHERE WE HAD PLENTY OF SUNSHINE BEFORE
CONVECTION ERUPTED. RAP/NAM/GFS SOUNDINGS ALL SUGGEST ANY 0-1 MLCIN
FROM NOCTURNAL INFLUENCES BEING NEARLY COMPLETELY GONE BY 15Z.
THEREFORE IT IS CONCEIVABLE FOR CONVECTION TO FIRE SHORTLY
THEREAFTER WHEN 0-1 MLCAPE IS ONLY AT 800-1500 J/KG. HRRR/RAP MODELS
SHOW CONVECTION FIRING IN THAT 15-16Z WINDOW...IN AGREEMENT WITH THE
ABOVE ANALYSIS. THE CONVECTION MAY STABILIZE THINGS BRIEFLY...BUT
PERSISTENT HEATING THROUGH THE DAY COMBINED WITH SOUTHERLY WARM
ADVECTION OF INSTABILITY SHOULD PROVIDE FUEL TO CONTINUE PERIODS OF
CONVECTION THROUGH THE DAY AND INTO THE EVENING. PASSAGE OF THE
UPPER TROUGH AND NOCTURNAL COOLING SHOULD ALLOW CONVECTION TO
SUBSIDE AFTER MIDNIGHT.
REGARDING SEVERE POTENTIAL...THE LIMITATION OF BUILDING A LOT OF
CAPE IS A HINDRANCE. 0-6KM SHEAR FROM THE 30.00Z NAM/GFS IS
GENERALLY PROGGED AT 25-30 KT THROUGH THE DAY...FAVORING FOR MORE OF
A MULTI-CELL SITUATION. WITH INSTABILITY STRUGGLING...NOT THINKING
MUCH IN THE WAY FOR SEVERE HAIL. BULK OF THE AFOREMENTIONED 0-6KM
SHEAR IS IN THE 0-3KM LAYER...AND COMBINED WITH 850MB WINDS PROGGED
IN THE AFTERNOON AND EVENING OF 45-50 KT DOES BRING UP A CONCERN FOR
THE STORMS TO PRODUCE STRONG TO DAMAGING WIND GUSTS. 0-1KM SHEAR IS
QUITE HIGH AS WELL FOR THE AFTERNOON AND EVENING...SIMILAR TO 0-3KM
OF 25-30KT...SO WE MAY WANT TO WATCH FOR POSSIBLE TORNADOES TOO.
THIS WOULD BE ESPECIALLY TRUE ALONG ANY CONVECTIVE OUTFLOW BOUNDARY
AND/OR IF WE CAN GET MORE DAYTIME HEATING THAN EXPECTED.
ON THE FLOODING FRONT...MORE INFORMATION CAN BE FOUND IN THE
HYDROLOGY SECTION BELOW. BRIEFLY...THE PATTERN TODAY INTO THIS
EVENING IS VERY FAVORABLE FOR STORMS TO TRAIN ACROSS THE SAME AREAS
AS THEY MARCH SOUTH TO NORTH. WITH PRECIPITABLE WATER VALUES STAYING
UP IN THE 1.5-1.75 INCH RANGE ANY STORM CAN PRODUCE HEAVY RAIN. WITH
GROUNDS ALREADY SATURATED...FLASH FLOODING IS CERTAINLY POSSIBLE...
ESPECIALLY SOUTH OF I-90 WHICH WAS REALLY IMPACTED FROM YESTERDAY
INTO LAST NIGHT.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 333 AM CDT THU MAY 30 2013
LOW PRESSURE OVER THE EASTERN DAKOTAS PUSHES SOUTHEAST LATE FRIDAY
MORNING INTO FRIDAY AFTERNOON DRIVING THE FRONT ACROSS THE FORECAST
AREA. DEPENDING ON THE TIMING OF THIS FRONT...SEVERE WEATHER POSSIBLE
ON FRIDAY. FORECAST MODELS ARE IN REASONABLE AGREEMENT...SHOWING
0-3 KM MUCAPE VALUES CLIMBING TO 2000 TO 3000 J/KG. SHEAR IS ALSO
RAMPING UP LATE FRIDAY MORNING INTO FRIDAY AFTERNOON WITH 0-6 KM
BULK SHEAR INCREASING TO 45 TO 55 KTS. THE HIGHEST INSTABILITY
APPEARS TO BE OVER FAR NORTHEAST IOWA AND INTO EXTREME SOUTHWEST
WISCONSIN. WILL HAVE TO KEEP A VERY CLOSE WATCH ON THIS OVER THE
NEXT FEW MODEL RUNS. AT THIS TIME...LARGE HAIL AND DAMAGING WINDS
APPEAR TO BE THE MAIN HAZARDS FROM THESE STORMS. BUT AGAIN...THE
SEVERE THREAT AREA WILL DEPEND ON WHERE THE BOUNDARY IS LOCATED
LATE FRIDAY MORNING INTO FRIDAY AFTERNOON AND HOW MUCH SURFACE
HEATING IS REALIZED. A DRY SLOT PUSHES INTO THE FORECAST AREA LATE
FRIDAY NIGHT AS THE LOW PUSHES EAST INTO THE WESTERN GREAT LAKES.
THERE SHOULD BE A DRY PERIOD AS THE LOW MOVES IN...BUT THEN
SHOWERS AND ISOLATED THUNDERSTORMS WILL DEVELOP ON SATURDAY AS THE
LOW SLIDES ACROSS THE REGION. AN UNSEASONABLY COOL AIRMASS MOVES
INTO REGION ON SUNDAY. 850 MB TEMPERATURES FALL TO 0 C OVER
NORTHERN WISCONSIN AND TO AROUND 2 C OVER NORTHEAST IOWA. THIS
WILL SET THE STAGE FOR A CHILLY NIGHT ACROSS THE AREA SUNDAY NIGHT
INTO EARLY MONDAY MORNING. ECMWF 850 MB TEMPERATURE STANDARDIZED
ANOMALIES FALL TO AROUND -1.5...INDICATIVE OF AN ANOMALOUSLY COLD
AIRMASS. TEMPERATURES WILL PLUMMET INTO THE UPPER 30S OVER FAR
NORTHERN WISCONSIN. WILL HAVE TO KEEP A VERY CLOSE WATCH ON LOWS OVER
NORTH CENTRAL AND CENTRAL WISCONSIN WHERE TYPICAL COLD SPOTS SUCH
AS SPARTA AND BLACK RIVER FALLS COULD SEE LOWS DIP INTO THE UPPER
30S...LEADING TO FROST FORMATION. COOL HIGH PRESSURE REMAINS OVER
THE REGION THROUGH TUESDAY...WITH HIGHS ONLY IN THE 60S. HIGH
PRESSURE PUSHES EAST OF THE REGION LATE TUESDAY INTO WEDNESDAY AS
A TROUGH DIGS INTO THE DAKOTAS. SOUTHERLY FLOW DEVELOPS OVER THE
AREA HELPING TO USHER IN WARMER TEMPERATURES. THE TROUGH WILL MOVE
INTO THE FORECAST AREA LATE TUESDAY NIGHT THROUGH WEDNESDAY
BRINGING CHANCES FOR SHOWERS AND THUNDERSTORMS TO THE AREA.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 600 AM CDT THU MAY 30 2013
DIFFICULT FORECAST FOR TIMING OF OCCASIONAL TO SCATTERED -SHRA/TS
TODAY INTO TONIGHT. CHAOTIC SKY...LEFT OVER SURFACE BOUNDARIES...AND
UPPER LEVEL PIECES OF ENERGY COULD ALSO SERVE AS PCPN TRIGGERS.
WHERE THESE WILL BE...TIMING...AND WHEN SHRA/TS FIRE IS NOT CLEAR.
MEANWHILE...THE MAIN IMPETUS WILL BE WHERE THE LOW LEVEL MOISTURE
TRANSPORT INTERACTS WITH ANY OF THESE FEATURES. CONFIDENCE IS
HIGHEST FOR THE AFTERNOON AND EVENING HOURS...BUT ONLY FOR VCTS/VCSH
AT THIS TIME. UPDATES WILL BE NEEDED FOR KRST/KLSE TO BETTER REFINE
THE PCPN THREATS AS THEY BECOME MORE EVIDENT.
LOOK FOR AN INCREASE IN WINDS EARLY THIS MORNING AS MIXING KICKS IN
AND 40 KTS OF WIND SITS AROUND 2 KFT. LLWS STILL A THREAT UNTIL
14Z...BUT THERE SHOULD BE ENOUGH MIXING AT THE SFC - THUS INCREASE
IN THE SFC BASED WIND - THAT LLWS IN THE TAFS WILL NO LONGER BE
NEEDED. WINDS WILL STAY UP FOR MUCH OF TONIGHT AS TIGHT PRESSURE
GRADIENT HOLDS ACROSS THE REGION. BUFKIT SOUNDINGS AND SREF MODEL
GUIDANCE ALSO FAVOR A LOWERING OF THE CLOUD DECK INTO THE MVFR
CATEGORY. NOT ENTIRELY SOLD ON THIS...BUT ENOUGH SIGNALS FAVOR IT
THAT WILL ADD FOR THE OVERNIGHT HOURS.
&&
.HYDROLOGY...TODAY AND TONIGHT
ISSUED AT 333 AM CDT THU MAY 30 2013
HEAVY RAIN FELL ACROSS THE AREA WEDNESDAY AFTERNOON AND EVENING
WITH RAINFALL AMOUNTS OF 2 TO 3 INCHES REPORTED ACROSS PORTIONS OF
NORTHEAST IOWA...SOUTHEAST MINNESOTA AND SOUTHWEST
WISCONSIN...WITH LOCALLY HIGHER AMOUNTS OF 4 INCHES REPORTED. AN
ADDITIONAL 1 TO 2 INCHES OF RAIN IS EXPECTED ACROSS THE AREA
TODAY THROUGH THIS EVENING...WHICH COULD LEAD TO FLASH FLOODING.
IT WILL NOT TAKE MUCH RAIN OVER THE SATURATED SOILS TO CREATE
FLOODING ISSUES. ALSO...AREA RIVERS WILL SEE RISES AND POSSIBLE
FLOODING WITH ANY ADDITIONAL RAINFALL RECEIVED. HAVE EXPANDED THE
FLASH FLOOD WATCH NORTHWARD...INCLUDING AREAS ALONG AND SOUTHWEST
OF INTERSTATE 94 CORRIDOR EXCLUDING JUNEAU COUNTY
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR WIZ032>034-041-042-
053>055-061.
MN...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR MNZ079-086>088-
094>096.
IA...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR IAZ008>011-018-019-
029-030.
&&
$$
SHORT TERM...AJ/WETENKAMP
LONG TERM....WETENKAMP
AVIATION.....RIECK
HYDROLOGY....WETENKAMP
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1040 AM CDT SAT JUN 1 2013
.DISCUSSION...
ISSUED 1040 AM CDT SAT JUN 1 2013
15Z/10AM SURFACE CHART SHOWS LOW PRESSURE OVER WESTERN
WISCONSIN...WITH TRAILING COLD FRONT EXTENDING ACROSS EASTERN IOWA
INTO NORTH-CENTRAL MISSOURI. NOT MUCH HAPPENING IMMEDIATELY
ALONG/AHEAD OF THE FRONT YET...HOWEVER STILL HAVE PLENTY OF
ONGOING RAIN FURTHER SOUTH IN THE OHIO RIVER VALLEY ASSOCIATED
WITH LAST NIGHTS STORM COMPLEX. LIGHT RAIN CONTINUES TO FALL
ACROSS THE S/SE KILX CWA...MAINLY ALONG AND SOUTH OF A PARIS TO
EFFINGHAM LINE. 12Z NAM AND HRRR TRY TO PUSH A WAVE OF THIS PRECIP
FURTHER NORTH INTO THE DECATUR AND CHAMPAIGN AREAS...HOWEVER SEE NO
EVIDENCE OF THIS HAPPENING ON RADAR/SATELLITE LOOPS. WILL
THEREFORE FOCUS LIKELY POPS ACROSS THE S/SE CWA...WITH ONLY LOW
CHANCE FURTHER NORTH ACROSS MUCH OF CENTRAL ILLINOIS THROUGH THE
EARLY AFTERNOON. AFTER THAT...MODELS INDICATE SCATTERED CONVECTION
FIRING ALONG THE COLD FRONT BY MID TO LATE AFTERNOON...MAINLY
ALONG AND WEST OF I-55. WILL GO WITH CHANCE POPS ACROSS THE BOARD
IN THE AFTERNOON...WITH BEST CHANCES ACROSS THE WESTERN HALF OF
THE CWA. FRONT WILL PROGRESS EASTWARD...TAKING BEST RAIN CHANCES
INTO EAST-CENTRAL ILLINOIS THIS EVENING...THEN COMPLETELY OUT OF
THE AREA OVERNIGHT. ZONE UPDATE WILL BE ISSUED SHORTLY.
BARNES
&&
.AVIATION...
ISSUED 658 AM CDT SAT JUN 1 2013
BRIEF BREAK FOR ILX TERMINALS...AS MOST OF SHOWERS AND TS SOUTH OF
DEC. HOWEVER...THIS IS SHORT LIVED AS THIS AFTERNOON THE TS
ACTIVITY WILL REFIRE/MOVE IN FROM THE SW ALONG THE SLOW MOVING
COLD FRONT. 4KM WRF AND RAP MODELS BOTH POINTING TO TS DEVELOPMENT
FROM SPI TO CMI AROUND 18Z. KEEPING JUST A SHOWER MENTION IN PIA
AND BMI AT THIS TIME...AS NRN TERMINALS WILL BE ON THE FRINGE OF
THE MAIN AREA OF PRECIP...AND ONLY IN SCT ACTIVITY WITH DIURNAL
INFLUENCES. AFTER 09Z A DEVELOPMENT OF LOW MVFR CIGS POSSIBLE AS
THE SYSTEM MOVES OUT AND AMPLE LLVL MOISTURE GETS TRAPPED IN THE
BOUNDARY LAYER AND TURNS INTO A STRATUS DECK SIMILAR TO WHAT SAT
IMAGERY AND OBS HAVE IN THE PIA TO SPI AND POINTS WEST THIS
MORNING.
HJS
&&
.PREV DISCUSSION...
ISSUED 311 AM CDT SAT JUN 1 2013
MCS AND ASSOCIATED SEVERE WEATHER CONTINUES IN A WIDE SWATH FROM
SOUTHERN INDIANA TO OKLAHOMA EARLY THIS MORNING. WORST OF THE
STORMS HAVE EXITED THE CWA...ALTHOUGH SOME WIDESPREAD LIGHT TO
MODERATE RAIN CONTINUES EAST OF I-55 AS OF 245 AM.
MAIN CONCERN FOR THIS FORECAST PACKAGE IS OVER THE NEXT 18
HOURS... WITH SEVERE WEATHER AND FLOODING POTENTIAL CONTINUING.
SHORT TERM...TODAY THROUGH MONDAY...
EMPHASIS ON FLOOD POTENTIAL WILL MAINLY BE ACROSS THE SOUTHEAST
HALF OF THE CWA TODAY...AS AXIS OF HIGH PRECIPITABLE WATER VALUES
OF 1.75 TO 2 INCHES SHIFTS EASTWARD AHEAD OF THE DRY SLOT THAT
WILL ARRIVE THIS EVENING. HAVE DROPPED THE FLASH FLOOD WATCH FOR
AREAS WEST OF I-55 AS ADDITIONAL RAINFALL IN THIS AREA SHOULD BE
LESS THAN A QUARTER INCH. ANOTHER HALF TO 1 INCH POSSIBLE ACROSS
AREAS SOUTH OF I-70...WHICH HAVE BEEN HAMMERED WITH 2 TO 5 INCHES
OVER THE LAST COUPLE DAYS...AS FORECAST SOUNDINGS SHOW WARM CLOUD
DEPTH OF 11KFT IN THAT AREA. A RENEWED SURGE OF SHOWERS/STORMS
EXPECTED TO DEVELOP LATER THIS MORNING AND BE WIDESPREAD THIS
AFTERNOON. LATEST SPC SEVERE WEATHER OUTLOOK FOCUSES ON THE AREA
EAST OF HIGHWAY 51 FOR RENEWED SEVERE DEVELOPMENT. PRECIPITATION
SHOULD QUICKLY SHUT OFF EARLY THIS EVENING AS DRY SLOT PUNCHES IN
WITH THE SURFACE LOW PASSING TO OUR NORTH.
AFTER THAT...A COOLER AND MUCH QUIETER PERIOD IS ON TAP FOR A FEW
DAYS...AS A STRONG UPPER LOW SWINGS THROUGH THE NORTHERN GREAT
LAKES REGION. MAY SEE A FEW LIGHT SHOWERS SWING THROUGH ON
SUNDAY...MAINLY IN THE EASTERN CWA...AS A TROUGH QUICKLY MOVES
THROUGH THE AREA. HIGHS AROUND 70 WILL BE FAIRLY COMMON FOR SUNDAY
AND MONDAY.
LONG TERM...TUESDAY THROUGH FRIDAY...
MAIN CONCERN IN THIS TIME FRAME IS WITH TIMING OF SHOWERS/STORMS
DURING THE MIDDLE OF THE WEEK. MEDIUM RANGE MODELS IN REASONABLE
AGREEMENT WITH A CLOSED LOW TRACKING ACROSS MONTANA AND NORTH
DAKOTA THROUGH MIDWEEK. LATEST ECMWF AND CANADIAN MODELS HANG UP
THE UPPER LOW OVER THE MINNESOTA ARROWHEAD REGION...WHILE THE GFS
IS A BIT MORE PROGRESSIVE. WILL SLOWLY INCREASE RAIN CHANCES IN
THE GRIDS FROM WEST TO EAST...WITH MENTIONABLE POPS HOLDING OFF IN
THE SOUTHEAST CWA UNTIL THURSDAY. UPPER TROUGH SHOULD THEN TRACK
THROUGH ON FRIDAY...WITH SURFACE RIDGING BUILDING SOUTHWEST FROM
THE GREAT LAKES. AT THIS POINT...THINK THE CHANCES OF RAIN ON
FRIDAY ARE LOW...BUT WILL MAINTAIN SOME LOW POPS EAST OF I-55
CLOSER TO THE CENTER OF THE TROUGH.
GEELHART
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH UNTIL 7 PM CDT THIS EVENING FOR ILZ038-042>046-
051>057-061>063-066>068-071>073.
&&
$$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
715 AM CDT SAT JUN 1 2013
.DISCUSSION...
ISSUED 311 AM CDT SAT JUN 1 2013
MCS AND ASSOCIATED SEVERE WEATHER CONTINUES IN A WIDE SWATH FROM
SOUTHERN INDIANA TO OKLAHOMA EARLY THIS MORNING. WORST OF THE
STORMS HAVE EXITED THE CWA...ALTHOUGH SOME WIDESPREAD LIGHT TO
MODERATE RAIN CONTINUES EAST OF I-55 AS OF 245 AM.
MAIN CONCERN FOR THIS FORECAST PACKAGE IS OVER THE NEXT 18
HOURS... WITH SEVERE WEATHER AND FLOODING POTENTIAL CONTINUING.
SHORT TERM...TODAY THROUGH MONDAY...
EMPHASIS ON FLOOD POTENTIAL WILL MAINLY BE ACROSS THE SOUTHEAST
HALF OF THE CWA TODAY...AS AXIS OF HIGH PRECIPITABLE WATER VALUES
OF 1.75 TO 2 INCHES SHIFTS EASTWARD AHEAD OF THE DRY SLOT THAT
WILL ARRIVE THIS EVENING. HAVE DROPPED THE FLASH FLOOD WATCH FOR
AREAS WEST OF I-55 AS ADDITIONAL RAINFALL IN THIS AREA SHOULD BE
LESS THAN A QUARTER INCH. ANOTHER HALF TO 1 INCH POSSIBLE ACROSS
AREAS SOUTH OF I-70...WHICH HAVE BEEN HAMMERED WITH 2 TO 5 INCHES
OVER THE LAST COUPLE DAYS...AS FORECAST SOUNDINGS SHOW WARM CLOUD
DEPTH OF 11KFT IN THAT AREA. A RENEWED SURGE OF SHOWERS/STORMS
EXPECTED TO DEVELOP LATER THIS MORNING AND BE WIDESPREAD THIS
AFTERNOON. LATEST SPC SEVERE WEATHER OUTLOOK FOCUSES ON THE AREA
EAST OF HIGHWAY 51 FOR RENEWED SEVERE DEVELOPMENT. PRECIPITATION
SHOULD QUICKLY SHUT OFF EARLY THIS EVENING AS DRY SLOT PUNCHES IN
WITH THE SURFACE LOW PASSING TO OUR NORTH.
AFTER THAT...A COOLER AND MUCH QUIETER PERIOD IS ON TAP FOR A FEW
DAYS...AS A STRONG UPPER LOW SWINGS THROUGH THE NORTHERN GREAT
LAKES REGION. MAY SEE A FEW LIGHT SHOWERS SWING THROUGH ON
SUNDAY...MAINLY IN THE EASTERN CWA...AS A TROUGH QUICKLY MOVES
THROUGH THE AREA. HIGHS AROUND 70 WILL BE FAIRLY COMMON FOR SUNDAY
AND MONDAY.
LONG TERM...TUESDAY THROUGH FRIDAY...
MAIN CONCERN IN THIS TIME FRAME IS WITH TIMING OF SHOWERS/STORMS
DURING THE MIDDLE OF THE WEEK. MEDIUM RANGE MODELS IN REASONABLE
AGREEMENT WITH A CLOSED LOW TRACKING ACROSS MONTANA AND NORTH
DAKOTA THROUGH MIDWEEK. LATEST ECMWF AND CANADIAN MODELS HANG UP
THE UPPER LOW OVER THE MINNESOTA ARROWHEAD REGION...WHILE THE GFS
IS A BIT MORE PROGRESSIVE. WILL SLOWLY INCREASE RAIN CHANCES IN
THE GRIDS FROM WEST TO EAST...WITH MENTIONABLE POPS HOLDING OFF IN
THE SOUTHEAST CWA UNTIL THURSDAY. UPPER TROUGH SHOULD THEN TRACK
THROUGH ON FRIDAY...WITH SURFACE RIDGING BUILDING SOUTHWEST FROM
THE GREAT LAKES. AT THIS POINT...THINK THE CHANCES OF RAIN ON
FRIDAY ARE LOW...BUT WILL MAINTAIN SOME LOW POPS EAST OF I-55
CLOSER TO THE CENTER OF THE TROUGH.
GEELHART
&&
.AVIATION...
ISSUED 658 AM CDT SAT JUN 1 2013
BRIEF BREAK FOR ILX TERMINALS...AS MOST OF SHOWERS AND TS SOUTH OF
DEC. HOWEVER...THIS IS SHORT LIVED AS THIS AFTERNOON THE TS
ACTIVITY WILL REFIRE/MOVE IN FROM THE SW ALONG THE SLOW MOVING
COLD FRONT. 4KM WRF AND RAP MODELS BOTH POINTING TO TS DEVELOPMENT
FROM SPI TO CMI AROUND 18Z. KEEPING JUST A SHOWER MENTION IN PIA
AND BMI AT THIS TIME...AS NRN TERMINALS WILL BE ON THE FRINGE OF
THE MAIN AREA OF PRECIP...AND ONLY IN SCT ACTIVITY WITH DIURNAL
INFLUENCES. AFTER 09Z A DEVELOPMENT OF LOW MVFR CIGS POSSIBLE AS
THE SYSTEM MOVES OUT AND AMPLE LLVL MOISTURE GETS TRAPPED IN THE
BOUNDARY LAYER AND TURNS INTO A STRATUS DECK SIMILAR TO WHAT SAT
IMAGERY AND OBS HAVE IN THE PIA TO SPI AND POINTS WEST THIS
MORNING.
HJS
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH THROUGH THIS EVENING FOR ILZ038-042>046-
051>057-061>063-066>068-071>073.
&&
$$
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
943 AM EDT SAT JUN 01 2013
.Forecast Update...
Issued at 940 AM EDT Sat Jun 1 2013
Quite a bit of stratiform rain remains over portions of southern
Indiana and west central Kentucky this morning in the wake of the
line of storms early this morning. Showers further to the south are
a bit more convective in nature. Have updated the grids to reflect
the current radar trends and take the chances for thunderstorms this
morning down to isolated. It still looks like we could see more
convection developing this afternoon, though the best chances for
strong to severe storms looks to be over southern and eastern
portions of the region where cloud cover is less and more
instability can develop. There is still quite a bit of uncertainty
in the forecast and it will need to be monitored closely today to
see how things evolve.
&&
.Short Term (Now through Sunday)...
Issued at 309 AM EDT Sat Jun 01 2013
Rather complex forecast unfolding early this morning, as incoming
convection casts quite a bit of uncertainty onto the forecast for
this afternoon into the overnight hours. All of this action is in
response to an expansive upper-level low, which will accelerate into
the Great Lakes this afternoon. An associated cold front will slide
through the region this evening through the overnight hours,
allowing drier and cooler conditions to work in for Sunday.
An expansive MCS continues to slide southeast across portions of
Missouri/Illinois/Indiana this morning. This activity continues to
be fueled by a 40-50 knot low-level jet, supplying copious amounts
of moisture. Some of this activity has briefly caused some
marginally severe wind gusts. However, 0-3km shear vectors oriented
mainly parallel to the cold pool is prohibiting intense upright
convection along the gust front, thus keeping the severe threat
rather isolated. Nonetheless, an isolated severe storm or two
cannot be ruled out within small bowing segments as it approaches
from the northwest early this morning.
The major question then becomes how quickly this morning activity
dissipates/pushes east, and what effect that will have on
instability this afternoon and evening. Guidance is all over the
place, with the latest RAP guidance still depicting 2500 J/kg of
MLCAPE developing late this afternoon ahead of the cold front.
Think the NAM/GFS are more realistic, painting anywhere from about
800-1400 J/kg by late this afternoon. This parameter will be
paramount in determining the severe risk throughout the day, as
lingering clouds/precipitation through the day will largely mitigate
the severe risk. Most of the hi-res guidance focuses the best
instability across southern Kentucky, as this area is most likely to
be unaffected by this approaching morning MCS. This will create a
split across the CWA, with the better dynamics focused across
southern IN/northern KY, while the best instability will reside
across southern Kentucky. Regardless, as the main shortwave ejects
out of the larger scale trough and spreads height falls over the
synoptic cold front, widespread convection looks to break out late
this afternoon into the evening, especially across southern KY.
0-6km shear of 30-40 knots will favor organized convection across
the entire region. The accelerating cold front and large-scale
forcing for ascent will favor mainly a linear storm mode, although a
transient supercell structure will be possible as storms initially
develop. 0-1km shear values of 25-35 knots will promote at least
some tornado risk, although surface winds do not appear as if they
will be quite as backed (SSE) as was suggested in previous model
runs, thus lower 0-1SRH is forecast. Large hail will also be
possible, especially across southern Kentucky where the best
instability will reside, but the expected QLCS storm mode may temper
that threat as well. The bottom line: The severe threat will
largely hinge on afternoon destabilization. If we can destabilize,
a severe QLCS capable of mainly damaging winds will materialize.
Large hail and a few isolated tornadoes will also be possible. Stay
tuned to the forecast throughout the day as the details regarding
the decaying MCS and resulting instability become more apparent.
The synoptic cold front will push through by Sunday evening. Some
guidance is showing the potential for a few showers across southern
IN as the main trough axis swings through Sunday evening, but will
keep the forecast dry for now as moisture looks limited. Highs
Sunday will reach the upper 70s to lower 80s with westerly flow.
.Long Term (Sunday Night - Friday)...
Issued at 230 AM EDT Sat Jun 1 2013
No major changes, as an exiting front will bring lingering rains
only over the far eastern forecast area, as an upper trough passes.
Forecast highs for Monday will be roughly 5 degrees below normal,
under a brief thickness minimum that will allow for pleasant
readings through Tuesday. Upper ridge builds in Wednesday, so kept
low/nil rain chances through at least then, but temperatures will go
over climo slightly by the end of the work week. Lows will rise
uniformly Wednesday through Friday. Morning readings should start to
go above normal Thursday. Storm chances enter the picture again as
heights fall and moisture increases Thursday and Friday. Coverage
should be scattered, mainly during peak heating.
&&
.Aviation (12Z TAF Issuance)...
Issued at 715 AM EDT Sat Jun 01 2013
Rather complex forecast for this TAF period, as incoming morning
convection casts uncertainty on redevelopment this afternoon and
evening. In the near term, showers and thunderstorms will continue
to weaken as they push through KSDF and KBWG. Based on latest radar
trends, seems as if thunderstorms could linger a bit longer at KBWG
as the convection stalls its southward progression, thus will
continue VCTS through 14Z. Not sure KLEX will see much thunderstorm
activity (or even shower activity for that matter), thus will only
keep VCSH wording in for the morning hours.
The forecast for this afternoon largely hinges on the development of
instability and the location of any outflow boundaries. Guidance
continues to suggest that the atmosphere will recover enough to
produce additional convection as a surface cold front approaches.
The timing, strength, and location of this developing convection
remains rather uncertain due to the reasons above, thus will
continue with a rather prolonged period of VCTS. Any thunderstorm
will be capable of strong winds and MVFR/IFR ceilings and
visibilities. The cold front will push into the TAF sites toward
the end of the period, bringing a lower stratus deck with it. Will
introduce MVFR ceilings for this, but even lower ceilings may be
needed in coming forecasts.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
KY...NONE.
$$
Update...........EER
Short Term.......KD
Long Term........RJS
Aviation.........KD
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
715 AM EDT SAT JUN 01 2013
...Updated Aviation Discussion...
.Short Term (Now through Sunday)...
Issued at 309 AM EDT Sat Jun 01 2013
Rather complex forecast unfolding early this morning, as incoming
convection casts quite a bit of uncertainty onto the forecast for
this afternoon into the overnight hours. All of this action is in
response to an expansive upper-level low, which will accelerate into
the Great Lakes this afternoon. An associated cold front will slide
through the region this evening through the overnight hours,
allowing drier and cooler conditions to work in for Sunday.
An expansive MCS continues to slide southeast across portions of
Missouri/Illinois/Indiana this morning. This activity continues to
be fueled by a 40-50 knot low-level jet, supplying copious amounts
of moisture. Some of this activity has briefly caused some
marginally severe wind gusts. However, 0-3km shear vectors oriented
mainly parallel to the cold pool is prohibiting intense upright
convection along the gust front, thus keeping the severe threat
rather isolated. Nonetheless, an isolated severe storm or two
cannot be ruled out within small bowing segments as it approaches
from the northwest early this morning.
The major question then becomes how quickly this morning activity
dissipates/pushes east, and what effect that will have on
instability this afternoon and evening. Guidance is all over the
place, with the latest RAP guidance still depicting 2500 J/kg of
MLCAPE developing late this afternoon ahead of the cold front.
Think the NAM/GFS are more realistic, painting anywhere from about
800-1400 J/kg by late this afternoon. This parameter will be
paramount in determining the severe risk throughout the day, as
lingering clouds/precipitation through the day will largely mitigate
the severe risk. Most of the hi-res guidance focuses the best
instability across southern Kentucky, as this area is most likely to
be unaffected by this approaching morning MCS. This will create a
split across the CWA, with the better dynamics focused across
southern IN/northern KY, while the best instability will reside
across southern Kentucky. Regardless, as the main shortwave ejects
out of the larger scale trough and spreads height falls over the
synoptic cold front, widespread convection looks to break out late
this afternoon into the evening, especially across southern KY.
0-6km shear of 30-40 knots will favor organized convection across
the entire region. The accelerating cold front and large-scale
forcing for ascent will favor mainly a linear storm mode, although a
transient supercell structure will be possible as storms initially
develop. 0-1km shear values of 25-35 knots will promote at least
some tornado risk, although surface winds do not appear as if they
will be quite as backed (SSE) as was suggested in previous model
runs, thus lower 0-1SRH is forecast. Large hail will also be
possible, especially across southern Kentucky where the best
instability will reside, but the expected QLCS storm mode may temper
that threat as well. The bottom line: The severe threat will
largely hinge on afternoon destabilization. If we can destabilize,
a severe QLCS capable of mainly damaging winds will materialize.
Large hail and a few isolated tornadoes will also be possible. Stay
tuned to the forecast throughout the day as the details regarding
the decaying MCS and resulting instability become more apparent.
The synoptic cold front will push through by Sunday evening. Some
guidance is showing the potential for a few showers across southern
IN as the main trough axis swings through Sunday evening, but will
keep the forecast dry for now as moisture looks limited. Highs
Sunday will reach the upper 70s to lower 80s with westerly flow.
.Long Term (Sunday Night - Friday)...
Issued at 230 AM EDT Sat Jun 1 2013
No major changes, as an exiting front will bring lingering rains
only over the far eastern forecast area, as an upper trough passes.
Forecast highs for Monday will be roughly 5 degrees below normal,
under a brief thickness minimum that will allow for pleasant
readings through Tuesday. Upper ridge builds in Wednesday, so kept
low/nil rain chances through at least then, but temperatures will go
over climo slightly by the end of the work week. Lows will rise
uniformly Wednesday through Friday. Morning readings should start to
go above normal Thursday. Storm chances enter the picture again as
heights fall and moisture increases Thursday and Friday. Coverage
should be scattered, mainly during peak heating.
&&
.Aviation (12Z TAF Issuance)...
Issued at 715 AM EDT Sat Jun 01 2013
Rather complex forecast for this TAF period, as incoming morning
convection casts uncertainty on redevelopment this afternoon and
evening. In the near term, showers and thunderstorms will continue
to weaken as they push through KSDF and KBWG. Based on latest radar
trends, seems as if thunderstorms could linger a bit longer at KBWG
as the convection stalls its southward progression, thus will
continue VCTS through 14Z. Not sure KLEX will see much thunderstorm
activity (or even shower activity for that matter), thus will only
keep VCSH wording in for the morning hours.
The forecast for this afternoon largely hinges on the development of
instability and the location of any outflow boundaries. Guidance
continues to suggest that the atmosphere will recover enough to
produce additional convection as a surface cold front approaches.
The timing, strength, and location of this developing convection
remains rather uncertain due to the reasons above, thus will
continue with a rather prolonged period of VCTS. Any thunderstorm
will be capable of strong winds and MVFR/IFR ceilings and
visibilities. The cold front will push into the TAF sites toward
the end of the period, bringing a lower stratus deck with it. Will
introduce MVFR ceilings for this, but even lower ceilings may be
needed in coming forecasts.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
KY...NONE.
$$
Short Term.......KD
Long Term........RJS
Aviation.........KD
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
1017 AM EDT SAT JUN 1 2013
.SYNOPSIS...
HIGH PRESSURE REMAINS ANCHORED OFF THE MID ATLANTIC COAST THROUGH
SUNDAY. A COLD FRONT SLOWLY CROSSES THE AREA MONDAY AND MONDAY NIGHT
THEN MOVES OFF THE COAST EARLY TUESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
CRNT FCST ON TRACK AS STRNG RIDGE REMAINS OFF THE COAST. HIGH RES
MODELS DVLP CONVECTION OVR MTS AFTR 18Z. HOWEVER...DATA SPRTS THIS
CONVECTION WEAKENING AND OR DSPTG B4 GETTING INTO AKQ CNTYS. THIS
SPRTD BY THE CAP ON 12Z SNDGS. RUC ACTUALLY INDCTG SOME MSTR DVLPNG
ACROSS SERN VA / NE NC ARND 21Z DUE TO MERGING SEA BREEZE BNDRYS.
WILL MONITOR RADAR TRENDS AS DAY WEARS ON...BUT FOR NOW KEPT A DRY
FCST THIS AFTRN AND EVE. POP CAPPED AT 14%. HIGH TMPS U80S-L90S
XCPT COOLER AT THE BEACHES.
M CLR TO PT CLDY TONIGHT. LOWS IN THE U60S TO ARND 70.
&&
.SHORT TERM /SUNDAY THROUGH TUESDAY/...
A COLD FRONT WILL APPROACH FROM THE WEST ON SUNDAY. AS THE FRONT
ENCOUNTERS THE AFOREMENTIONED RIDGE...IT WILL SLOW DOWN AND EVEN
STALL ACROSS THE MID ATLANTIC STATES MONDAY. THE EURO IS A GOOD
COMPROMISE BETWEEN THE FASTER GFS AND SLOWER NAM.
PCPN WILL GRADUALLY DEVELOP FROM THE WEST SUNDAY AFTN AND SUNDAY
NIGHT. MODERATE INSTABILITY WILL RESULT IN SCATTERED TSTMS OVER
FAR WRN COUNTIES SUNDAY AFTN. THIS WILL BE AIDED BY UPPER LEVEL
DIVERGENCE ...A RESULT OF A NEGATIVELY TILTED UPPER LEVEL TROUGH
OVER THE EASTERN GREAT LAKES. MOST OF THE DIVERGENCE WILL BE TO
OUR NORTH. PCPN BECOMES LIKELY OVER MUCH OF THE NRN AND WRN
PORTIONS OF THE CWA OVERNIGHT SUNDAY NIGHT AND THUNDERSTORMS WILL
BE PSBL. FAR SE PORTIONS SHOULD REMAIN DRY THROUGH EARLY MONDAY
MORNING.
HAVE LIKELY POPS ACRS ALL BUT FAR SE PORTIONS DURING THE DAY MONDAY
AS THE FRONT BECOMES DIFFUSE OVER THE MID ATLANTIC STATES. DID NOT
WANT TO GO CATEGORICAL POPS AS MOS POPS ARE GENERALLY FROM 50 TO
60 PERCENT.
AN UPR LEVEL SPEED MAX TO THE NORTH AND POCKETS OF INSTABILITY
DURING THE DAY MONDAY WILL RESULT IN THE POSSIBILITY OF SCATTERED
EMBEDDED THUNDERSTORMS. PCPN WILL BE SLOW TO DEPART THE AREA FROM
WEST TO EAST MONDAY NIGHT. BY TUESDAY MORNING...THE FRONT BECOMES
BETTER DEFINED AND MOVES OFFSHORE. THE AREA SHOULD BE DRY EXCEPT
IN THE SE VA AND NE NC WHERE SHOWERS SHOULD END BY MIDDAY. THE
NAM KEEPS PCPN IN THE AREA LONGER BUT THIS IS IN THE OUTER RANGE
OF THAT MODEL WHICH IS GENERALLY LESS RELIABLE THAN EARLIER
PORTIONS OF THE MODEL.
PRECIPITABLE WATER ACCORDING TO THE NAM INCREASES TO BETWEEN 1.7 AND
2.0 INCHES ON MONDAY. THIS SHOULD RESULT IN A GOOD SOAKING. WPC QPF
FORECASTS HAVE INCREASED RAINFALL FOR THE AREA IN ASSOCIATION WITH
THE PCPN EVENT LATE SUNDAY THROUGH EARLY TUESDAY. HAVE BLENDED
THEIR FORECAST INTO OURS WHICH RESULT IN THREE QUARTERS TO ONE AND
A HALF INCHES TOTAL PCPN ACROSS THE CWA. LATER FORECASTS MAY NEED
TO BUMP THE QPF HIGHER.
DAYTIME TEMPERATURES WILL LOWER SLIGHTLY SUNDAY WITH HIGHS IN THE
MID TO UPR 80S. WITH PCPN AND CLOUD COVER...TEMPERATURES ON MONDAY
WILL RUN FROM NEAR 80 TO THE MIDDLE 80S. MAXIMUM READINGS ON TUESDAY
ARE EXPECTED TO REACH THE MID TO UPR 70S WITH NEAR 80 DEGREES IN THE
SOUTHERN VIRGINIA PIEDMONT. LOWS WILL BE IN THE MID TO UPR
60S...LOWERING TO AROUND 60 OVER THE PIEDMONT TUESDAY MORNING.
&&
.LONG TERM /TUESDAY NIGHT THROUGH FRIDAY/...
HI PRES WILL BLD FM THE GRT LKS EWRD INTO NEW ENGLAND TUE AFTN INTO
THU MORNG...THEN SLIDE OFF THE NEW ENGLAND CST FOR THU AFTN THRU
FRI. WILL MAINTAIN A DRY FCST THRU THE EXTENDED PERIOD WITH
COMFORTABLE TEMPS/HUMIDITY AT LEAST FOR TUE INTO THU. MIN TEMPS WILL
BE IN THE MID 50S TO LWR 60S WED AND THU MORNGS...AND IN THE UPR 50S
TO MID 60S FRI MORNG. MAX TEMPS WILL BE IN THE MID 70S TO LWR 80S
WED AND THU...AND IN THE UPR 70S TO MID 80S FRI.
&&
.AVIATION /14Z SATURDAY THROUGH WEDNESDAY/...
HIGH PRESSURE OFF THE COAST CONTINUES TO BRING A WARM S-SW FLOW OVER
THE REGION. DECIDED TO DROP FOG AT TAF SITES AS TEMP/DEW PT SPREADS
ARE GENLY 5-10 F OR GREATER...AND WINDS ARE STILL GENLY 5-10 KT.
MAINLY SUNNY THIS MORNING WITH SOME SCATTERED AFTN CU ONCE AGAIN.
S/SW WINDS AVG 10-15 KT.
OUTLOOK...WHILE MODELS ARE INDICATING A SLIGHTLY BETTER CHANCE FOR FOG
OR LOW CLOUDS EARLY SUNDAY MORNING...THE WARM SW FLOW REGIME AND
WINDS STAYING 5-10 KT OVERNIGHT WOULD SUGGEST ONLY A LIMITED
POTENTIAL OF PATCHY FOG (MORE LIKELY TO BE LOW CLOUDS). IT DOES
APPEAR THAT GUIDANCE IS BEGINNING TO BACK OFF ON THE LOW CLOUD
SCENARIO AS WELL SO FOR THE MOST PART WOULD ANTICIPATE MAINLY VFR
CONDITIONS AND ANY LOWER CIGS/VSBYS WOULD BE BRIEF. SCATTERED
SHRA/TSRA WILL BE POSSIBLE BY SUNDAY EVENING...AND BECOME LIKELY
ON MONDAY. DRY/VFR CONDITIONS RETURN FROM NW TO SE ON TUE (SOME
SHRA/LOW CLOUDS MAY LINGER THROUGH MIDDAY TUE AT KORF/KECG).
DRY/VFR TUE NIGHT-WED IN NE FLOW.
&&
.MARINE...
WILL NOT HAVE ANY HEADLINES ON THIS FCST ISSUANCE...BUT MAY NEED
SCA`S FOR SEAS ON THE THREE NRN CSTL ZNS LATER ON FOR TONIGHT INTO
MON...AND INCREASING SOUTHERLY FLOW MAY GET CLOSE TO SCA CRITERIA
TONIGHT (ALTHOUGH EXPECT ANY GUSTS TO 20 KT TO BE BRIEF/NOT
FREQUENT ENOUGH FOR SCA HEADLINES IN THE BAY). OTHERWISE...HIGH PRES
WILL REMAIN ANCHORED OFF THE MID ATLC CST INTO AT LEAST MON
MORNG...WITH S/SW WINDS AVERAGING 10 KT TODAY...15 KT
TONIGHT/SUNDAY (15 TO 20 KT ON THE COAST TONIGHT THRU SUN NIGHT). A
COLD FRONT WILL PUSH ACRS THE WTRS AND OFF THE CST MON THRU TUE.
WINDS WILL SHIFT TO THE NW THEN NNE AVERAGING AROUND 15 KT (BUT
WILL PROBABLY SEE A BRIEF SURGE OF HIGHER WINDS AND AS TIMING
BECOMES MORE CERTAIN MAY SEE LOW END SCA CONDITIONS FOR A FEW
HOURS AS THE HIGH BUILDS IN FROM THE NW EARLY TUE OR AGAIN TUE
NIGHT/EARLY WED.
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...SMALL CRAFT ADVISORY FROM MIDNIGHT TONIGHT TO 6 AM EDT MONDAY
FOR ANZ650-652.
&&
$$
SYNOPSIS...LSA
NEAR TERM...MPR/LSA
SHORT TERM...LSA
LONG TERM...TMG
AVIATION...LKB/MAS
MARINE...LKB
AREA FORECAST DISCUSSION
NWS GAYLORD MI
1034 AM EDT SAT JUN 1 2013
.SYNOPSIS...
ISSUED AT 258 AM EDT SAT JUN 1 2013
LOW PRESSURE WILL MOVE EAST FROM MINNESOTA...CROSSING NORTHERN
MICHIGAN TONIGHT. UNSETTLED WEATHER WILL CONTINUE THRU SUNDAY
MORNING...BEFORE THIS SYSTEM DEPARTS. MUCH COOLER AND DRIER AIR
WILL ENTER THE REGION BEHIND THE DEPARTING LOW. A COUPLE OF
FROSTY MORNINGS ARE POSSIBLE ON BOTH MONDAY AND TUESDAY.
&&
.UPDATE...
ISSUED AT 1033 AM EDT SAT JUN 1 2013
ANOTHER TOUGH FORECAST FOR THE AFTERNOON/EARLY EVENING TIMEFRAME
ON WHAT IS SURELY A BUSY OUTDOOR WEEKEND. EARLY MORNING CONVECTION
NOW ROLLING UP THROUGH EASTERN UPPER MICHIGAN. CONVECTION WAS THE
RESULT OF COMPACT MCV (RADAR REFLECTIVITY PATTERN REVEALS THE
SPIN) THAT BROKE AWAY FROM LAST EVENINGS CONVECTION IN THE
MIDWEST AND PUSHED UP THROUGH THE REGION EARLY THIS MORNING. STILL
A FEW POCKETS OF SHOWERS TRAILING THE MCV ACROSS NRN LOWER
MICHIGAN.
FOR THIS AFTERNOON...AGAIN...TOUGH FORECAST. AS MENTIONED ABOVE...
BEHIND THE DEPARTING MCV ISOLATED SHOWERS AND THUNDER CONTINUES TO
POP UP ACROSS NRN AND CENTRAL LOWER MICHIGAN DESPITE LOWER VALUES
OF INSTABILITY...EVIDENCE OF THE UNCAPPED ENVIRONMENT STILL IN
PLACE. QUESTION IS...WILL ONGOING ACTIVITY CONTINUE TO GROW
UPSCALE AS WE SLOWLY HEAT UP. NAM AND RUC FORECAST SOUNDINGS DO
REVEAL A WINDOW OF OPPORTUNITY THROUGH EARLY TO MID AFTERNOON
WITH BETWEEN 500 AND 1000 J/KG MLCAPE ACROSS NRN LOWER MICHIGAN
AND LITTLE TO NO CINH. BUT SIMILAR TO YESTERDAY...BOTH NAM AND GFS
SOUNDINGS SUGGEST MIXING WILL ULTIMATELY TAP DRIER AIR ALOFT AND
DROP SFC DEWPOINTS BACK INTO 50S TO LOWER 60S. SO...GUT FEELING IS
WE CONTINUE TO SEE ISOLATED-SCT SHOWERS/THUNDER THROUGH EARLY TO
MID AFTERNOON BEFORE ACTIVITY GETS SQUASHED. WILL GO THAT ROUTE
FOR NOW AND JUST SEE WHAT HAPPENS.
UPDATE ISSUED AT 659 AM EDT SAT JUN 1 2013
GRIDS UPDATED TO ACCOUNT FOR WELL-DEFINED BAND OF CONVECTION
LIFTING ACROSS NW/N CENTRAL LOWER MI. APX DOPPLER SHOWED SOME
HIGHLY LOCALIZED 50KT INBOUNDS 15-20SM SW OF THE RADAR AS THE
STORMS APPROACHED...BUT NO SURPRISE (GIVEN A SLIGHTLY STABLE
BOUNDARY LAYER) THAT THOSE WINDS ARE NOT GETTING TO THE GROUND.
&&
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 258 AM EDT SAT JUN 1 2013
CURRENTLY, THERE IS A 850 MB THETA-E GRADIENT THAT RUNS N ILLINOIS
THROUGH LAKE MICHIGAN, INTO E UPPER, AND THEN INTO ONTARIO NORTH OF
ANJ. THE SHOWERS (MAYBE A THUNDERSTORM, ALTHOUGH NO CG STRIKES WERE
OBSERVED) HAVE BEEN MOVING WITH THAT BOUNDARY OVERNIGHT, WHICH ARE
JOINING UP WITH THE THUNDERSTORMS THAT ARE NOW OVER LAKE SUPERIOR
THAT WERE OVER W UPPER LAST EVENING. WITH THE 1000-850 MB LAYER WIND
OUT OF THE SSW, AND THE SHOWERS LOOK TO BE RIDING ALONG THOSE WIND
STREAMLINES, IT LOOKS LIKE WE WILL GET A BREAK THIS MORNING IN N
LOWER, WITH SCATTERED SHOWERS IN E UPPER.
TODAY...THIS IS STILL A SOMEWHAT COMPLICATED FORECAST, SINCE THERE
IS SOME UNCERTAINTY TO WHETHER THE BREAK THAT I ALLUDED TO WILL LAST
AS LONG AS WILL BE STATED. HOWEVER, BASED ON THE CURRENT TRENDS AND
THE LATEST MODELS, HERE`S WHAT LOOKS LIKE SHOULD HAPPEN. THE FIRST
THING THAT WILL BLOCK MOST OF THE CONVECTION IN OUR AREA IS THE
ONGOING CONVECTION DOWN SOUTH ALONG THE INDIANA/OHIO/MICHIGAN
BORDER. AS IT PROGRESSES EAST, THE MOISTURE AND ENERGY TRANSPORT
WILL BE CUT OFF TO ALLOW ANYTHING TO GET GOING IN NW LOWER AND E
UPPER. HOWEVER, SOME OF THE SHOWERS AND THUNDERSTORMS LOOKS LIKE
THEY MAY TRY TO SLIDE NORTH ALONG THE THETA-E BOUNDARY INTO NE LOWER
THIS MORNING. OTHERWISE, TO THE WEST, THERE IS A PRETTY HEFTY AREA
OF DRIER AIR WITH THE DEWPOINTS IN THE MID 50S(IN WISCONSIN), AND
RUNNING THE HYSPLIT MODEL BACKWARDS TO SEE WHERE THE AIR MASS IS
ORIGINATING FROM SHOWS A MIXTURE OF LOWER TO MID 60S DEWPOINTS FROM
SW LOWER(SURFACE AIR), AND LOWER DEWPOINTS (MID 40S) FROM SW IOWA
(1000 METER AGL AIR). THIS WOULD AGREE WITH THE GFS/NAM/ECMWF IDEA
OF A DRY SLOT WORKING INTO THE REGION AND PUTTING THE BREAKS ON THE
SHOWERS DURING THE DAY IN E UPPER AND NW LOWER, AND AS THE SFC LOW
MOVES EAST, THE DRY SLOT WILL WORK ITS WAY EAST AND PUSH THE THUNDER
POTENTIAL EAST, AS WELL. BY THE LATE AFTERNOON, MOST OF N LOWER WILL
BE IN THE DRIER AIR WITH THE THUNDER POTENTIAL WORKING ITS WAY BACK
INTO E UPPER AS THE BACK EDGE OF THE LOW PROVIDES SOME FORCING IN
THE INITIALLY WARM AIR MASS.
TONIGHT...AS THE LOW CONTINUES TO MOVE EAST, THE COOLER AIR BEGINS
TO MOVE INTO THE REGION. THIS WILL ALLOW FOR SHOWERS FROM THE 500 MB
TROUGH (AND THE MOISTURE ASSOCIATED WITH IT) TO PUSH INTO THE
FORECAST AREA. SINCE THIS IS AT NIGHT (NO SFC INSTABILITY), AND THE
700-500 MB LAPSE RATES ARE AROUND 6 C/KM, THINK THAT THE THUNDER
POTENTIAL GOES TO ZERO WITH RAIN SHOWERS EXPECTED IN THE COLD AIR.
THIS CONTINUES INTO THE NIGHT AND SPREADS TO THE SE COUNTIES BY 12Z.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 258 AM EDT SAT JUN 1 2013
OUR WX QUICKLY TURNS MUCH QUIETER...BUT MUCH COOLER...TO CLOSE OUT
THE WEEKEND. PRIMARY TROF EXTENDING FROM 500MB LOW NORTH OF SUPERIOR
WILL BE RIGHT OVERHEAD ON SUNDAY MORNING...AND WILL QUICKLY EJECT TO
THE EAST...EVEN AS THE UPPER LOW DIGS A BIT TOWARD SUPERIOR/S NORTH
SHORE. THIS LOW REMAINS PROGRESSIVE...PASSING JUST SOUTH OF JAMES
BAY MONDAY MORNING. 500MB SHORTWAVE RIDGING WILL GET PUMPED UP INTO
THE AREA BY TUESDAY MORNING...IN ADVANCE OF ENERGY MOVING INTO THE
DAKOTAS. OTHER THAN ANY LINGERING PRECIP CHANCES AT THE START OF THE
DAY SUNDAY...THE MAIN CHALLENGE IS MIN TEMPS AND ANY EARLY JUNE
FROST POTENTIAL.
SUNDAY...COLD ADVECTION WILL BE UNDERWAY ACROSS ALL OF NORTHERN MI
AT 12Z SUNDAY. DEEPER MOISTURE WILL BE DEPARTING SOON THEREAFTER...
BUT NOT QUITE IMMEDIATELY. HAVE SOME CONCERNS THAT THE NAM (AS IT
LIKES TO DO) IS OVERDOING THE LOW-LEVEL MOISTURE PRESENT UP TIL 18Z.
BUT GIVEN THE 500MB TROF AXIS IS ONLY ALONG A NEWBERRY-TVC AXIS AT
DAYBREAK...WOULD CERTAINLY STILL MAKE SENSE FOR SOME EARLY AM SHRA
TO LINGER. WILL KEEP THINGS SIMPLE...WITH A CHANCE OF -SHRA ACROSS
THE AREA SUNDAY MORNING. SHARPLY DRIER AIR ARRIVES IN THE PM...WITH
850-700MB RH LEVELS BELOW 40 PERCENT. WILL REMOVE PM POPS. THAT
DRIER AIR WILL SERIOUSLY ERODE LINGERING COLD-AIR STRATOCU...
ESPECIALLY BY LATE AFTERNOON/EARLY EVENING. 850MB TEMPS TUMBLE TO
AROUND 1C BY EVENING...WHICH WILL PUT THE KIBOSH ON TEMPS GOING MUCH
OF ANYWHERE IN THE PM HOURS. THE NE LOWER COAST SHOULD STILL SHOOT
INTO THE LOW-MID 60S TO START THE DAY...ELSEWHERE HIGHS WILL BE IN
THE 50S.
SUN NIGHT/MONDAY...A POCKET OF DEEP MOISTURE WRAPPED AROUND THE
UPPER LOW WILL BE TUCKED JUST NORTH OF THE SAULT SUNDAY NIGHT INTO
MONDAY. BUT THE NAM/GFS AGREE THAT IT NEVER QUITE PINWHEELS DOWN
INTO EASTERN UPPER. SUPERIOR IS OF COURSE STILL VERY CHILLY (EASTERN
BUOY WATER TEMP IS 38F)...SO 850MB TEMPS NOSING DOWN PERHAPS AS LOW
AS -2C WILL NOT PROMPT A LAKE RESPONSE. SO CAN KEEP THESE PERIODS
DRY. EASTERN UPPER WILL GET GRAZED BY LOW/MID CLOUDS SWIRLING AROUND
THE PASSING LOW...NORTHERN LOWER WILL SEE LITTLE CLOUD COVER DURING
THESE PERIODS.
DOUBT THAT EASTERN UPPER AND THE NE LOWER MI COAST WILL DECOUPLE
SUNDAY NIGHT...AS THE PRESSURE GRADIENT REMAINS RATHER TIGHT THERE.
THE BULK OF NORTHERN LOWER LIKELY WILL...AS THE CENTER OF THE
UPSTREAM SURFACE HIGH DRIFTS FROM IOWA TOWARD CHICAGO. A LITTLE BIT
OF CLOUD COVER AND BREEZE WILL LIKELY KEEP EASTERN UPPER MIN TEMPS
IN THE MID TO UPPER 30S. NORTHERN LOWER WILL VARY MORE
SUBSTANTIALLY...NEAR 40F ALONG SOME COASTS BUT DIPPING DEEP INTO THE
30S IN INTERIOR COLD SPOTS (DEFINITELY THE AU SABLE VALLEY). WILL
FINE-TUNE FROST COVERAGE IN THE GRIDDED FORECASTS. BUT SUFFICE TO
SAY THERE IS A VERY GOOD CHANCE OF SEEING THAT FROST IN THE USUAL
INTERIOR COOL SPOTS (WHICH...FOR THOSE LOCATIONS...ISN/T THE LEAST
BIT UNUSUAL FOR THE 1ST WEEK OF JUNE).
NOT A LOT OF MODERATION IN THE AIRMASS FOR MONDAY. 850MB TEMPS STILL
RANGING FROM NEAR 0C IN EASTERN UPPER TO 2C IN SOUTHERN SECTIONS AT
MIDDAY. BUT LOTS OF SUNSHINE (ESPECIALLY IN NORTHERN LOWER) WILL
HELP. MAX TEMPS UPPER 50S EASTERN UPPER TO MID 60S IN SOUTHERN
SECTIONS.
REST OF THE FORECAST...ANOTHER CHILLY/POTENTIALLY FROSTY NIGHT ON
MONDAY NIGHT...WITH TEMPS IN ABOUT THE SAME BALLPARK AS SUNDAY
NIGHT. IN FACT...TEMPS LOOK TO REMAIN BELOW CLIMO THRU THE
FORECAST...AS A SERIES OF UPPER TROFS MIGRATING ACROSS THE NORTHERN
STATES KEEP SUMMER TEMPS AT BAY. QUIET WX WILL CONTINUE INTO TUESDAY
NIGHT...BEFORE SHOWER CHANCES ARRIVE WEDNESDAY. SMALLISH RAIN
CHANCES WILL LAST THRU THE REST OF THE WORK WEEK...AS THE NEXT UPPER
TROF SLOWLY TRANSITS THE REGION.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 659 AM EDT SAT JUN 1 2013
SHRA/TSRA EARLY THIS MORNING. SHRA AND MVFR CIGS RETURN TONIGHT.
LOW PRESSURE IN SOUTHERN MN WILL MOVE EAST...CROSSING NORTHERN MI
TONIGHT. A BAND OF SHRA/TSRA WILL CONTINUE TO LIFT ACROSS THE
REGION THIS MORNING...WITH 1-3 HOURS OF CIG/VSBYS RESTRICTIONS.
AFTER THAT...VFR...AND BETTER CHANCES FOR PRECIP ARRIVE WITH THE
LOW TONIGHT. HAVE PREVAILING SHRA AT ALL SITES FOR SEVERAL
HOURS...AND MVFR CIGS ARRIVING VERY LATE AS COOLER AIR SPILLS BACK
IN.
SOUTHERLY WINDS TODAY...VEERING NW LATE TONIGHT.
&&
.MARINE...
ISSUED AT 258 AM EDT SAT JUN 1 2013
WINDS WILL REMAIN BELOW SMALL CRAFT CRITERIA AS THE SFC GRADIENT
NEVER QUITE TIGHTENS UP ENOUGH TO GET ANY WIND GOING. THE SFC LOW
MOVES IN TONIGHT, WHICH KEEPS THE GRADIENT SLACK. BY SUNDAY, THE
GRADIENT TIGHTENS BACK UP, BUT SHOULD REMAIN JUST BLOW SMALL
CRITERIA, UNTIL THE LATE AFTERNOON WHEN THE GRADIENT TIGHTENS UP
MORE, AND SMALL CRAFT WIND GUSTS ARE EXPECTED. THIS WILL LAST INTO
SUNDAY NIGHT.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...NONE.
LM...NONE.
LS...NONE.
&&
$$
UPDATE...BA
SYNOPSIS...JZ
SHORT TERM...JL
LONG TERM...JZ
AVIATION...JZ
MARINE...JL
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
936 AM EDT SAT JUN 1 2013
.SYNOPSIS...
BERMUDA HIGH PRESSURE WILL HOLD OVER THE OFFSHORE WATERS THROUGH
THE WEEKEND. THE BEST CHANCE OF RAIN WILL ARRIVE MONDAY INTO
TUESDAY...AS A COLD FRONT DROPS SOUTHEAST ACROSS THE REGION. HIGH
PRESSURE WILL BUILD SOUTH ACROSS THE AREA THROUGH THE MIDDLE OF
NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 936 AM SATURDAY...AN EARLY SUMMER PATTERN APPEARS WELL IN
PLACE FOR TODAYS FORECAST...THOUGH A BIT DRY ALOFT PER 12Z RAOB
PLOTS FROM CHS/MHX. ISOLATED SHOWERS/TSTMS WILL BE RETAINED FOR
THIS AFTERNOON AS THE INLAND ADVANCING SEA BREEZE FRONT PLOWS TO
THE NW INTO A HUMID LOW-LEVEL AIR MASS WITH SURFACE DEWPOINTS
AROUND 70 DEG F ACROSS MUCH OF THE FORECAST AREA. THE SEA BREEZE
WILL BE THE ONLY IMPETUS FOR CONVECTIVE GENERATION AND SUBSEQUENT
LOWER TROPOSPHERIC OMEGA IN A NARROW BAND MARCHING INLAND THROUGH
THE AFTERNOON HOURS. POPS ARE SHAPED TO DROP BELOW MENTIONABLE
VALUES BY 22Z/6PM PER LATEST 4KM NSSL WRF AND HRRR 3KM DEPICTIONS.
MAXIMUM TEMPERATURES TODAY LOW TO MIDDLE 80S COAST AND COASTAL
INTERIOR TO THE UPPER 80S WELL INLAND REMOVED FROM THE COOLING
AND INLAND PROGRESSING MARINE LAYER. A QUIET AND FAIR EVENING AND
OVERNIGHT PERIOD ANTICIPATED...WITH MIDDLE AND UPPER 60S FOR LOW
TEMPS BY DAYBREAK SUNDAY WITH A LIGHT SOUTH WIND EXPECTED TONIGHT.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 3 AM SATURDAY...MID LEVEL DRY AIR AND WEAK SUBSIDENCE WILL
WORK TO KEEP THE REGION DRY SUN. DO THINK THERE WILL BE SOME
ISOLATED CONVECTION DEVELOPING ON THE SEABREEZE BUT BEST CHANCE FOR
PRECIP WILL BE LATER SUN ACROSS INLAND SC. INCREASING DEEP MOISTURE
AHEAD OF THE SLOWLY ADVANCING COLD FRONT AND WEAKENING SUBSIDENCE AS
RIDGING RETREATS LEADS TO DEVELOPMENT OF LATE AFTERNOON SHOWERS AND
THUNDERSTORMS. INHERITED SLIGHT CHANCE TO CHANCE POP IS REASONABLE
BUT HAVE EXPANDED CHC POP AREA A BIT FARTHER EAST.
SECOND HALF OF THE PERIOD APPEARS QUITE WET WITH SHOWERS AND
THUNDERSTORMS A GOOD BET. DEEP MOIST SOUTHWEST FLOW WILL PUMP PLENTY
OF GULF MOISTURE INTO THE REGION AHEAD OF THE COLD FRONT.
PRECIPITABLE WATER VALUES APPROACH 2 INCHES MON AFTERNOON AND
EVENING IN CONJUNCTION WITH SOME WEAK DIVERGENCE ALOFT. MID LEVEL
LAPSE RATES ARE ON THE WEAK SIDE BUT CONVERGENCE AHEAD OF AND ALONG
THE FRONT SHOULD BE ABLE TO TAP INTO WHAT MID LEVEL INSTABILITY IS
PRESENT. ENVIRONMENT IS NOT SUPPORTIVE OF ANY SIGNIFICANT SEVERE
THREAT MON/MON NIGHT BUT DEEP MOISTURE...SLOW STORM MOTION...AND
DEEP WARM CLOUD LAYER SUGGEST STORMS THAT DO DEVELOP WILL HAVE
POTENTIAL TO DROP A LOT OF RAIN.
HIGH TEMPERATURES WILL BE NEAR TO SLIGHTLY BELOW CLIMO. TEMPERATURES
WILL BE WARMEST SUN WITH INCREASING MOISTURE AND EARLIER CLOUD
DEVELOPMENT LIMITING HIGHS ON MON. LOWS WILL REMAIN ABOVE CLIMO BOTH
NIGHT...HELD UP BY DEBRIS CLOUD AND LOW LEVEL MOISTURE.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
AS OF 3 AM SATURDAY...SLOW MOVING COLD FRONT WILL BE IN THE AREA AT
THE START OF THE PERIOD. LIMITED MID LEVEL PUSH KEEPS THE FRONT
ALONG THE COAST FOR AT LEAST FIRST PART OF TUE SO PRECIP MAY LINGER
INTO AFTERNOON. INHERITED CHC POP SEEMS REASONABLE AND WILL BE
MAINTAINED.
MIDDLE TO END OF THE WEEK REMAINS IN QUESTION AS POTENTIAL
DEVELOPMENT OF TROPICAL OR SUBTROPICAL SYSTEM IN THE GULF OF MEXICO
AND ITS MOISTURE PLUME CLOUDS THE FUTURE. ILL DEFINED MID LEVEL
PATTERN AND HIGH PRESSURE BUILDING IN FROM THE NORTH LEADS TO A WEAK
WEDGE TYPE SET UP. ANTICIPATE A SCATTERED TO BROKEN FLAT STRATOCU
DECK WITH LIMITED POTENTIAL FOR PRECIP WED/THU GIVEN VERY LITTLE
FORCING AND DEEP DRY AIR ALOFT. BEST CHANCE WOULD BE ALONG THE COAST
AS SHOWERS OVER THE WATERS MOVE ONSHORE. NORTHEAST TO EAST FLOW WILL
KEEP HIGHS SLIGHTLY BELOW CLIMO WHILE HOLDING LOWS NEAR TO SLIGHTLY
ABOVE.
LARGE DEGREE OF UNCERTAINTY LATE WITH RESPECT TO SYSTEM EMERGING
FROM GULF OF MEXICO. GFS/ECMWF/CANADIAN ALL SHOW THE FEATURE BUT
WITH WILDLY DIFFERENT SOLUTIONS. 00Z CANADIAN LOOKS NOTHING LIKE ITS
12Z RUN AND IS BEING DISCOUNTED FOR NOW. LATEST GFS SOLUTION KEEPS
THE LOW WELL OFF THE SOUTHEAST COAST AS IT MOVES NORTHEAST ALONG
REMAINS OF WASHED OUT COLD FRONT. LACK OF SIGNIFICANT STEERING LEVEL
FEATURES AND A FAIRLY WEAK SURFACE PATTERN SUPPORT A SLOWER
SOLUTION...RULING OUT THE LATEST CANADIAN. GIVEN THE LACK OF
STEERING FEATURES THINK THE LOW IS GOING TO TRAVEL NORTHEAST ALONG
THE REMAINS OF THE TROUGH...SIMILAR TO WHAT THE LATEST GFS IS
SUGGESTING. FOR NOW WILL TREND FORECAST IN THAT DIRECTION...THOUGH
THE 12Z ECMWF SOLUTION...WHICH IS SLOWER/DEEPER AND MOVES THE
SYSTEM INTO THE SOUTHEAST...CANNOT NOT BE TOTALLY DISCOUNTED.
HIGHS ARE LIKELY TO END UP BELOW CLIMO LATE NEXT WEEK WITH LOWS
RUNNING A LITTLE ABOVE CLIMO.
&&
.AVIATION /13Z SATURDAY THROUGH WEDNESDAY/...
AS OF 13Z...FOG IS DENSEST INLAND AND THINNEST JUST INLAND OF THE
COAST THIS MORNING. LIFR/VLIFR VSBYS/CIGS FROM KFLO-KLBT SHOULD
RISE TO VFR AROUND 13Z...ALTHOUGH THERE IS A CHANCE MVFR VSBYS
COULD LINGER UNTIL 14Z. OTHERWISE VFR EXPECTED AT THE TERMINALS
TODAY WITH SOUTHEAST TO SOUTH WINDS...STRONGEST AT THE COAST.
ISOLATED SHOWERS WILL POSSIBLY DEVELOP NEAR THE COASTAL TERMINALS
LATER THIS MORNING AS THE SEA BREEZE FORMS AND BEGINS TO PROGRESS
INLAND. MODELS ARE NOT INDICATING ANY SIGNIFICANT LIFT NOR
COVERAGE SO WILL DROP THE MENTION OF TS FROM PREVIOUS TAFS. ONCE
THE SEA BREEZE PUSHES FURTHER INLAND OF THE COASTAL TERMINALS BY
THIS AFTERNOON THE CHANCE OF SHOWERS AND CLOUD COVERAGE WILL
DECREASE AT THE COASTAL TERMINALS. ATTM WILL NOT MENTION ANY
PRECIPITATION IN THE KFLO/KLBT TAFS DESPITE THE SEA BREEZE MOVING
INTO THESE TERMINALS IN THE AFTERNOON. VFR EXPECTED THIS EVENING
AND WILL INDICATE ANOTHER ROUND OF FOG/STRATUS AFTER MIDNIGHT WITH
WORST CONDITIONS AT KFLO/KLBT.
EXTENDED OUTLOOK...EARLY MORNING MVFR/IFR CIGS/VSBYS POSSIBLE EARLY
SUNDAY AND MONDAY. INCREASING MVFR/IFR PRODUCING CONVECTION CHANCES AND
COVERAGE MONDAY AND TUESDAY...DROPPING BACK TO ISOLATED WEDNESDAY.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 936 AM SATURDAY...NO MARINE HAZARDS ANTICIPATED TODAY OR
TONIGHT ASIDE FROM INCREASED WEEKEND BOATING TRAFFIC ON THE
WATERS. BERMUDA HIGH PRESSURE AND THE SEA BREEZE CIRCULATION WILL
INDUCE S-SE WINDS TODAY...INCREASING A BIT IN THE AFTERNOON TO
AROUND 15 KT FROM INLAND HEATING AND CONSERVATION OF MASS LAWS.
THE SEA SPECTRUM WILL BE COMPRISED OF SE WAVES AROUND 3 FEET AT 8
SECONDS AND A SLIGHT SOUTHERLY CHOP...BECOMING MODERATE NEAR SHORE
IN THE AFTERNOON TO EARLY EVENING. NO TSTMS OR RESTRICTIONS TO
VISIBILITY EXPECTED TODAY OR TONIGHT.
SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 3 AM SATURDAY...SOUTHERLY FLOW BELOW 10 KT AT THE START OF THE
PERIOD INCREASES TO 10 TO 15 KT SUN AFTERNOON...REMAINING SOUTHERLY
AND IN THE 10 TO 15 KT RANGE THROUGH THE END OF THE PERIOD. BERMUDA
HIGH RETREATS SUN NIGHT AND MON AS COLD FRONT APPROACHES FROM THE
WEST. OVERALL LITTLE CHANGE TO PRESSURE GRADIENT ANTICIPATED WHICH
WILL KEEP SPEEDS IN THE 10 TO 15 KT RANGE THROUGH MON NIGHT. SEAS
WILL RUN 3 TO 4 FT FOR MUCH OF THE PERIOD.
LONG TERM /TUESDAY THROUGH WEDNESDAY/...
AS OF 3 AM SATURDAY...COLD FRONT STALLING IN THE AREA TUE WILL LEAD
TO LIGHT AND VARIABLE WINDS...EVENTUALLY BECOMING NORTHERLY BY TUE
EVENING. GRADIENT REMAINS WEAK TUE NIGHT WITH SPEEDS 10 KT OR LESS.
NORTHEAST FLOW BECOMES MORE ESTABLISHED WED AS HIGH PRESSURE NOSES
DOWN THE COAST. PINCHED GRADIENT RESULTS IN NORTHEAST FLOW
INCREASING TO 15 TO 20 KT WED AND WED NIGHT. SEAS AROUND 3 FT TO
START THE PERIOD WILL BUILD TO 3 TO 5 FT WED AND WED NIGHT.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...MJC
SHORT TERM...III
LONG TERM...III
AVIATION...MRR
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
950 AM CDT SAT JUN 1 2013
.UPDATE...
ISSUED AT 950 AM CDT SAT JUN 1 2013
LOW CU DEVELOPING BEHIND MAIN CLOUD BAND WITH LOW CONVECTIVE
TEMPERATURE VALUES. RAP GUIDANCE SUGGESTS THIS WILL CONTINUE
THROUGH THE AFTERNOON. WILL DELAY CLEARING AND LOWER MAX TEMPS A
FEW DEGREES. NO OTHER UPDATES NEEDED.
&&
.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 410 AM CDT SAT JUN 1 2013
MODELS ARE IN GOOD AGREEMENT OVERALL...AND PREFER THE CONSISTENT GFS.
FOR TODAY...EXPECT SKIES TO CLEAR FROM NORTH TO SOUTH. IT WILL BE
WINDY WITH GUSTS TO AROUND 35MPH AT TIMES. IT WILL BE BORDERLINE
WIND ADVISORY CRITERIA...BUT EXPECT IT TO REMAIN JUST BELOW
ADVISORY LEVELS. TEMPS WILL BE COOL FOR THIS TIME OF YEAR...AND
MOST AREAS WILL NOT REACH 60.
FOR TONIGHT...IT WILL BE COLD WITH TEMPS BELOW NORMAL. CAN/T RULE
OUT SOME FOG GIVEN WET CONDITIONS...BUT FOR NOW WILL NOT MENTION
BUT MONITOR.
ON SUNDAY...EXPECT PLENTIFUL SUNSHINE WITH HIGH PRESSURE OVERHEAD.
TEMPS WILL STILL REMAIN BELOW NORMAL BUT IT WILL BE WARMER THAN
TODAY.
.LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY)
ISSUED AT 410 AM CDT SAT JUN 1 2013
FOR SUNDAY NIGHT...ANOTHER COOL NIGHT IS EXPECTED BUT NOT QUITE AS
COLD AS TONIGHTS TEMPS.
ON MONDAY...THE CHANCES FOR SHOWERS WILL INCREASE IN THE WEST BY
AFTERNOON...AS THE NEXT SLOW MOVING STORM SYSTEM APPROACHES.
TEMPS COULD BE WARMER IF MORE SUNSHINE OCCURS...ESPECIALLY IN THE
NORTHEAST WHERE IT COULD TURN OUT TO BE MOSTLY SUNNY.
FOR TUESDAY THROUGH FRIDAY...SPLIT FLOW IS EXPECTED ACROSS CANADA
AND THE US. LONG WAVE TROUGH OVER THE NORTHERN PLAINS SHIFTS
SLIGHTLY EAST THROUGH THE PERIOD. LONG WAVE RIDGE OVER SOUTHERN
CANADA SHIFTS EAST AND FLATTENS BY THE END OF THE PERIOD.
GFS WAS TRENDING SLOWER FROM MODEL RUN TO MODEL RUN WHILE THE ECMWF
WAS TRENDING FASTER. WILL PREFER A BLEND OF THE TWO MODELS. SO
TODAYS PRECIPITATION WAS SLIGHTLY FASTER THAN YESTERDAYS RUN.
LITTLE CHANGE TO TEMPS FROM YESTERDAYS PACKAGE. HIGH TEMPS HAVE BEEN
LOWERED A DEGREE OR TWO FOR TUE AND WED AND A DEGREE OR TWO HIGHER
FOR THU AND FRI.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 650 AM CDT SAT JUN 1 2013
CONDITIONS WILL IMPROVE INTO THE VFR RANGE FROM NW TO SE THROUGH
THE DAY. IT WILL BE WINDY WITH GUSTS TO AROUND 30KT AT TIMES
MAINLY THIS MORNING. WINDS WILL DECREASE QUICKLY THIS EVENING WITH
HIGH PRESSURE AND CLEAR SKIES BUILDING INTO THE REGION.
&&
.HYDROLOGY...
ISSUED AT 410 AM CDT SAT JUN 1 2013
JUST OVER 4 INCHES OF RAIN FELL YESTERDAY IN THE GRAFTON AREA.
RUNOFF FROM TODAYS RAIN ALONG WITH RUNOFF FROM THURSDAYS HEAVY
RAIN IN THE PARK RIVER AREA WILL PUSH THE PARK RIVER AT GRAFTON TO
MAJOR FLOOD STAGE ON SUNDAY. THE PEMBINA RIVER AT NECHE WILL ALSO
SEE FURTHER RISES TO MAJOR FLOOD STAGE EARLY SUNDAY. AN AREAL
FLOOD WARNING REMAINS IN PLACE FOR ALL OF WALSH COUNTY. THE
SOUTHERN RED RIVER BASIN AND SOUTHERN TRIBUTARIES WILL CONTINUE TO
SLOWLY FALL.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...TG
SHORT TERM...DK
LONG TERM...HOPPES/DK
AVIATION...DK
HYDROLOGY...DK
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
643 AM EDT SAT JUN 1 2013
.SYNOPSIS...
OCCASIONAL THUNDERSTORMS WILL CONTINUE TODAY INTO TONIGHT AHEAD
OF AN APPROACHING COLD FRONT. HIGH PRESSURE WILL SETTLE INTO THE
AREA FOR THE FIRST PART OF THE UPCOMING WEEK...USHERING IN A DRIER
AND COOLER AIRMASS.
&&
.NEAR TERM /THROUGH TONIGHT/...
LINE OF CONVECTION EXTENDING FROM SOUTHERN ILLINOIS UP INTO
NORTHEAST INDIANA HAS BEEN PUSHING VERY SLOWLY EAST THROUGH THE
EARLY MORNING HOURS. THE AIRMASS JUST OUT AHEAD OF IT REMAINS AT
LEAST MARGINALLY UNSTABLE...BUT THE INSTABILITY DOES DROP OFF
FARTHER EAST ACROSS OHIO. THE ORIENTATION OF THE 20-30 KNOT 0-3 KM
SHEAR VECTORS WOULD SUGGEST THAT THIS LINE WILL MAINTAIN ITSELF
OVER THE NEXT SEVERAL HOURS AS IT PROGRESSES EAST...BUT AS IT
BEGINS TO ENCOUNTER THE MORE STABLE AIRMASS...EXPECT TO SEE SOME
WEAKENING IN THE STORM STRENGTH. AS A RESULT...THINK SHOWERS AND
THUNDERSTORMS WILL MAKE IT INTO AT LEAST OUR WESTERN AREAS LATER
THIS MORNING...BUT THINK SEVERE THREAT IS FAIRLY LOW.
QUITE A BIT OF UNCERTAINTY EXISTS FOR HOW THINGS WILL PLAY OUT
THROUGH THE REMAINDER OF THE DAY. AS PCPN WORKS EAST...DEBRIS
CLOUDS SHOULD OVERSPREAD OUR FA THROUGH THE REST OF THE MORNING.
THIS WILL PLAY A ROLE IN HOW FAST WE ARE ABLE TO RECOVER THROUGH
THIS AFTERNOON AND DESTABILIZE. BOTH THE 00Z NAM AND 00Z GFS ARE
SUGGESTING ML CAPES IN THE 500-1000 J/KG RANGE LATER TODAY...WITH
THE HIGHEST VALUES ACROSS THE SOUTH. MEANWHILE...THE RAP IS
CONSIDERABLY MORE UNSTABLE...BUT LIKELY OVERDONE WITH SURFACE
DEWPOINTS IN THE LOW 70S.
INCREASING MID LEVEL FLOW THROUGH THE DAY WILL COUPLE WITH A
PERSISTENT 20-30 KNOT 850 MB JET TO PRODUCE INCREASING LOW AND DEEP
LAYER SHEAR AS WE PROGRESS THROUGH THE DAY. THIS MAY BE ENOUGH TO
OVERCOME SOME OF THE POSSIBLE LACK OF INSTABILITY TO STILL RESULT
IN SOME ORGANIZED CONVECTION. WITH CONTINUED GOOD MOISTURE
TRANSPORT UP INTO OUR AREA AND PWS AROUND 150 PERCENT OF
NORMAL...LOCALLY HEAVY RAIN IS LIKELY WITH ANY OF THE STORMS.
CONSIDERED A FLASH FLOOD WATCH FOR AT LEAST THE NORTHWEST HALF OF
OUR AREA...BUT CONFIDENCE IS JUST TOO LOW ON BOTH THE DEGREE OF
DEVELOPMENT AND THE PLACEMENT.
EXPECT HIGHS RANGING FROM THE UPPER 70S NORTHWEST TO MID 80S
SOUTHEAST...BUT THESE TOO WILL BE DEPENDENT ON THE AMOUNT OF
DEBRIS CLOUDS.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY/...
THE BEST SEVERE THREAT WILL LIKELY BE THIS EVENING AS SHOWERS AND
THUNDERSTORMS BECOME MORE WIDESPREAD AHEAD OF THE APPROACHING COLD
FRONT. THIS WILL COINCIDE WITH THE HIGHEST 0-1KM BULK SHEAR AS IT
PUSHES UP INTO THE 25-30 KNOT RANGE AND BETTER DEEP LAYER SHEAR
DROPS DOWN FROM THE NORTHWEST. WOULD EXPECT DAMAGING WIND TO BE
THE PRIMARY THREAT...BUT GIVEN THE AMOUNT OF LOW LEVEL SHEAR...AN
ISOLATED TORNADO WILL ALSO BE POSSIBLE.
THUNDERSTORMS WILL TAPER OFF TO SHOWERS FROM THE NORTHWEST
OVERNIGHT AS WE GET ON THE BACKSIDE OF THE FRONT AND START TO LOSE
OUR INSTABILITY. SHOWERS AND PERHAPS A FEW THUNDERSTORMS MAY LINGER
INTO SUNDAY ACROSS OUR SOUTHEAST...WITH A FEW SPOTTY SHOWERS
ELSEWHERE AS THE MID LEVEL TROUGH AXIS PIVOTS ACROSS OUR AREA.
COOLER AIR MOVING IN BEHIND THE FRONT WILL KEEP HIGHS IN THE 70S
FOR SUNDAY. HIGH PRESSURE AND A DRIER/COOLER AIRMASS WILL THEN
SETTLE INTO THE AREA FOR MONDAY. EXPECT HIGHS ON MONDAY ONLY IN
THE UPPER 60S TO LOWER 70S.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
DETERMINISTIC MODELS ARE IN FAIRLY GOOD AGREEMENT THROUGH ABOUT MID
WEEK...THEN THEY START TO DIVERGE ON THE NEXT UPR LVL LOW IN TERMS
OF STRENGTH AND SPEED TOWARD THE END OF THE WEEK. HAVE USED A BLEND
OF MODEL RUNS THROUGH WEDNESDAY...THEN SIDED WITH THE 31.12Z ECMWF
AND HPC THEREAFTER.
FOR MONDAY NIGHT INTO TUESDAY...CANADIAN HIGH PRESSURE WILL
SETTLE INTO THE GREAT LAKES AND OHIO VALLEY. MOSTLY CLEAR SKIES
WILL BE FOLLOWED BY MOSTLY SUNNY CONDITIONS ON TUESDAY. COOL
OVERNIGHT LOWS WILL RESULT ONCE AGAIN IN BELOW NORMAL HIGHS ON
TUESDAY IN THE UPPER 60S TO THE LOWER 70S.
FOR WEDNESDAY INTO THURSDAY...SURFACE HIGH PRESSURE IS FORECAST TO
SLIDE EAST AS A WEAK MID LVL RIDGE MOVES ACROSS THE GREAT LAKES.
SKIES WILL BECOME PARTLY CLOUDY WITH A MODIFICATION IN THE AIRMASS.
FOR THURSDAY NIGHT INTO FRIDAY...UPR LVL LOW WILL SLOWLY MOVE FROM
THE NRN PLAINS INTO THE WRN GREAT LAKES. MOISTURE FUNNELING
NORTHWARD AHEAD OF A WEAK FRONTAL BOUNDARY WILL RESULT IN A THREAT
FOR SHOWERS AND THUNDERSTORMS. HAVE KEPT POPS IN THE CHANCE CATEGORY
AT THIS TIME DUE TO WEAK FEATURES. TEMPERATURES WILL BE NEAR
SEASONAL NORMALS BY THE END OF THE WEEK.
&&
.AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...
WEAKENING BAND OF SHOWERS MAY AFFECT WESTERN TERMINALS THROUGH THE
MID MORNING BEFORE DISSIPATING. WINDS WILL BECOME GUSTY LATER THIS
MORNING AND WILL CONTINUE THROUGH THE AFTERNOON. SOME REDEVELOPMENT
OF SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE ACROSS THE EASTERN
TERMINALS DURING THE EARLY TO MIDDLE AFTERNOON. A COLD FRONT
APPROACHING THE REGION LATER TONIGHT WILL BRING A ROUND OF
THUNDERSTORMS TO THE AREA DURING THE LATE AFTERNOON AND EVENING.
THIS ACTIVITY WILL SPREAD FROM WEST TO EAST WITH THE POSSIBILITY
FOR STRONG TO SEVERE STORMS CONTAINING BRIEF YET STRONG SHIFTING
WINDS AS THESE STORMS PASS. MVFR/IFR CIGS AND VSBYS WILL BE
POSSIBLE DURING ANY STORMS THIS AFTERNOON THROUGH TONIGHT. CIGS WILL
LIKELY REMAIN MVFR LATE TONIGHT AS THE COLD FRONT MOVES ACROSS THE
AREA AND STORMS EXIT THE REGION TO THE EAST.
OUTLOOK...MVFR CIGS MAY LINGER INTO THE DAY MONDAY.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...JGL
NEAR TERM...JGL
SHORT TERM...JGL
LONG TERM...HICKMAN
AVIATION...LATTO
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
704 AM CDT SAT JUN 1 2013
.DISCUSSION...
LOOK FOR MVFR CEILINGS TO DOMINATE WEST CENTRAL TEXAS FOR MUCH OF
THIS MORNING. SEE AVIATION BELOW FOR DETAILS.
&&
.AVIATION...
A COLD FRONT WILL PUSH SOUTH ACROSS WEST CENTRAL TEXAS TODAY AND
BRING MVFR CEILINGS ALONG AND AHEAD OF IT...AS WELL AS THE
POSSIBILITY FOR THUNDERSTORMS THIS AFTERNOON AND EVENING. THE
LATEST SATELLITE DATA INDICATE STRATUS...ALTHOUGH VERY
PATCHY...IS DEVELOPING ACROSS PORTIONS OF WEST CENTRAL TEXAS SOUTH
OF INTERSTATE 20. NORTH OF INTERSTATE 20...THE COLD FRONT HAS
ENTERED THE BIG COUNTRY. STRATUS IS DEVELOPING ALONG AND JUST
SOUTH OF THIS BOUNDARY. BY 18Z THIS AFTERNOON...THE RUC BRINGS THE
FRONT NEAR A MERTZON TO BROWNWOOD LINE. SOME THUNDERSTORMS MAY
DEVELOP ALONG AND BEHIND THIS FRONT THIS AFTERNOON. HOWEVER...WE
ANTICIPATE MOST THUNDERSTORMS TO DEVELOP EITHER LATE AFTERNOON OR
EARLY EVENING. CEILINGS SHOULD IMPROVE ACROSS MOST OF WEST CENTRAL
TEXAS BY 18Z...AS MIXING IN THE BOUNDARY LAYER BECOMES MORE
DOMINATE. BEHIND THE FRONT...PLAN FOR GUSTY NORTH TO NORTHEAST
WINDS. SOME THUNDERSTORMS MAY LINGER WELL INTO
TONIGHT...ESPECIALLY ACROSS THE NORTHERN EDWARDS PLATEAU AND THE
NORTHWEST HILL COUNTRY. SOME THUNDERSTORMS MAY BE SEVERE THIS
AFTERNOON. THE MAIN THREATS WILL BE LARGE HAIL AND DAMAGING WINDS.
IN ADDITIONS...SOME THUNDERSTORMS MAY PRODUCE HEAVY
RAINFALL...ESPECIALLY ACROSS OUR HEARTLAND AND NORTHWEST HILL
COUNTRY COUNTIES LATER THIS AFTERNOON AND EVENING. SO...BE
CAUTIOUS OF THE POTENTIAL FOR RAPIDLY REDUCED
VISIBILITY...ESPECIALLY DURING TAKEOFF AND LANDING.
HUBER
&&
.PREV DISCUSSION... /ISSUED 333 AM CDT SAT JUN 1 2013/
SHORT TERM...
A COLD FRONT WILL PUSH SOUTH INTO WEST CENTRAL TEXAS TODAY AND
CREATE CONDITIONS FAVORABLE FOR THUNDERSTORMS. THE FRONT SHOULD BE
NEAR OUR INTERSTATE 20 CORRIDOR AROUND NOON. MODEL FORECAST
SOUNDINGS...FOR SEVERAL LOCATIONS ACROSS WEST CENTRAL TEXAS THIS
AFTERNOON...INDICATE SURFACE BASED CAPE VALUES MAINLY IN THE 2000 TO
3000 J/KG RANGE. ALSO...FLOW AT 500 MB WILL BE SLIGHTLY DIVERGENT
OVER WEST CENTRAL TEXAS IN MAINLY WESTERLY FLOW. MY ONLY CONCERN IS
HOW MUCH OF A CAP WE WILL NEED TO OVERCOME TO INITIATE CONVECTION
THIS AFTERNOON. SURFACE CONVERGENCE ALONG AND NEAR THE FRONT MAY BE
ENOUGH TO OVERCOME THE CAP. HOWEVER...WITH MODEL FORECAST SOUNDINGS
INDICATING TEMPERATURES AT 700 MB THIS AFTERNOON AROUND 12 DEGREES
CELSIUS...MY CONFIDENCE IS NOT AS HIGH AS I WOULD LIKE IT TO BE
REGARDING THUNDERSTORM DEVELOPMENT. SO OFTEN THE CAP OVER WEST
CENTRAL TEXAS IS STUBBORNLY PERSISTENT AND DIFFICULT TO BREAK.
SO...I DECIDED TO MAINTAIN ONLY SLIGHT CHANCE POPS FOR MOST OF OUR
COUNTIES THIS AFTERNOON. IF THE CAP BREAKS THIS AFTERNOON...SEVERE
THUNDERSTORMS WILL LIKELY DEVELOP. THE MAIN THREATS WILL BE LARGE
HAIL AND DAMAGING WINDS.
FOR THIS EVENING AND LATER TONIGHT...THUNDERSTORMS DEVELOPMENT ALONG
AND NEAR THE SURFACE FRONT WILL REMAIN A POSSIBILITY. THE CAP AT 700
MB DOES DIMINISH BY AROUND 00Z. SURFACE BASED CAPES WILL STILL BE IN
THE 2000 TO 4000 J/KG RANGE...DEPENDING ON WHICH MODEL YOU USE.
SO...WITH LITTLE IF ANY CONVECTIVE INHIBITION...THUNDERSTORM
DEVELOPMENT APPEARS MORE LIKELY AFTER 00Z THIS EVENING. BY THAT
TIME...THE FRONT WILL HAVE MOVED FARTHER SOUTH ACROSS WEST CENTRAL
TEXAS TO NEAR OUR INTERSTATE 10 CORRIDOR. AGAIN...THUNDERSTORMS THIS
EVENING MAY BE SEVERE...WITH THE THREATS REMAINING THE SAME. IN
ADDITION...MODEL SOUNDINGS INDICATE PRECIPITABLE WATERS VALUES WILL
INCREASE THIS EVENING ACROSS WEST CENTRAL TEXAS...SOUTH OF
INTERSTATE 20...AND RANGE FROM AROUND ONE AND A QUARTER INCHES TO
ONE AND ONE HALF INCHES BETWEEN 00Z AND 06Z. THUS...FLASH FLOODING
WILL BE A CONCERN ACROSS OUR CENTRAL AND SOUTHERN COUNTIES
TONIGHT...ESPECIALLY DURING THE EVENING HOURS.
HUBER
LONG TERM...
BY SUNDAY MORNING THE FRONTAL BOUNDARY SHOULD BE JUST SOUTH OF THE
FORECAST AREA WITH SOME RESIDUAL SHOWER ACTIVITY OVER THE
SOUTHERN HALF OF THE CWA. SHOWERS SHOULD END BY MID-DAY SUNDAY
WITH SURFACE HIGH PRESSURE BUILDING SOUTH THROUGH THE PLAINS
STATES. AN UPPER LEVEL HIGH WILL BE POSITIONED OVER NORTHERN
MEXICO WITH AN ASSOCIATED RIDGE BUILDING NORTH OVER THE
SOUTHWESTERN STATES...WITH OUR CWA IN A NORTHWEST FLOW ALOFT.
THE 850MB THERMAL RIDGE 31C ISOTHERM WILL BE ENCROACHING ON OUR
WESTERN COUNTIES TUESDAY AFTERNOON AND ENVELOPING MOST OF THE
WESTERN CWA WEDNESDAY AFTERNOON. THIS SHOULD TRANSLATE TO TRIPLE
DIGITS OVER THE WESTERN CWA BOTH DAYS. DEGRADATION OF THE UPPER
LEVEL HIGH OVER NORTHERN MEXICO BEGINNING MID-WEEK WILL SHIFT THE
850MB THERMAL RIDGE WEST OF THE AREA AND ALLOW A FRONTAL BOUNDARY
TO DIP SOUTH INTO THE PANHANDLE AREA BY LATE WEDNESDAY. THIS WILL
BRING AFTERNOON HIGHS BACK INTO THE MID AND UPPER 90S BY THURSDAY
AND ALSO BRING A CHANCE OF RAINFALL ASSOCIATED WITH THE FRONTAL
BOUNDARY...BUT ANY RAINFALL AT THIS TIME LOOKS TO BE NORTH OF THE
FORECAST AREA. WILL KEEP OUR FORECAST DRY TROUGH THE EXTENDED WITH
AFTERNOON HIGHS REMAINING IN THE LOWER TO MID 90S. MORNING LOWS
SHOULD REMAIN IN THE UPPER 60S TO THE LOWER 70S.
&&
.PRELIMINARY POINT TEMPS/POPS...
ABILENE 88 62 87 66 92 / 30 20 5 10 10
SAN ANGELO 92 64 91 69 94 / 20 30 10 10 10
JUNCTION 94 68 92 68 93 / 20 40 20 10 10
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
HUBER
AREA FORECAST DISCUSSION
NWS SPOKANE WA
827 AM PDT Sat Jun 1 2013
.SYNOPSIS...
Most of the region will experience dry conditions today. The best
chance of showers, however, will be near the Canadian border this
afternoon as Sundays upper low approaches. This relatively strong
storm system will bring a cool- down with showers...thunderstorms and
breezy conditions for Sunday and Monday. The greatest threat of
precipitation will be across the eastern third of Washington and
the Idaho Panhandle Sunday. A drying and warming period will
greet the remainder of the new work week with temperatures
rising into the upper 70s and 80s by Tuesday.
&&
.DISCUSSION...
Update: Water vapor satellite imagery at 8 am showed a well
defined vort max over Vancouver Island moving into southern
British Columbia. Abundant mid and high clouds associated with
this wave will continue to stream into the Inland Northwest today
and sky cover has been adjusted upward a bit for the morning
hours mainly areas along and north of I-90 where mid level clouds
are more extensive. Latest HRRR falls in line with general model
consensus of showers developing over the mountains of the East
Slopes of the Cascades after about noon or 1 pm...and the north
portion of the Okanogan Highlands after 2 or 3 pm...with the bulk
of the showers north of the Canadian Border. With the best
instability and lift associated with this wave passing over
southern BC this idea makes sense. GFS and NAM show also show CAPE
values of around 200 J/KG which could result in a stray
thunderstorm. With low confidence of any lightning materializing
will leave out of forecast through the afternoon. The remainder of
the area is expected to remain dry through the afternoon. Made
some minor POP and weather adjustments based on above reasoning.
JW
&&
.AVIATION...
12Z TAFS: VFR conditions expected over the next 24 hrs. An
approaching upper level trough will bring thickening and lowering
clouds, with a chance for showers/t-storms for the Cascades and
northern mountains by Saturday afternoon and evening. Primary
shower chances are expected to remain away from TAF sites until
after 12Z Sunday...but some could be found in the vicinity of KEAT
after 06Z Sunday. /EK
&&
.PRELIMINARY POINT TEMPS/POPS...
Spokane 71 49 64 48 71 51 / 0 30 70 60 20 10
Coeur d`Alene 71 46 61 46 69 47 / 0 30 80 70 30 10
Pullman 71 45 65 45 69 47 / 0 20 60 60 20 10
Lewiston 78 53 73 52 75 53 / 0 10 50 50 10 10
Colville 74 46 69 47 77 49 / 10 50 60 50 20 10
Sandpoint 70 43 63 45 67 45 / 10 40 80 70 40 20
Kellogg 68 46 61 46 63 46 / 0 20 80 80 40 20
Moses Lake 76 49 76 50 81 52 / 0 10 10 10 0 0
Wenatchee 76 52 72 53 79 54 / 0 10 10 10 0 0
Omak 73 48 72 48 78 50 / 10 40 20 20 0 0
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...None.
&&
$$
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
648 AM CDT SAT JUN 1 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 321 AM CDT SAT JUN 1 2013
WHAT REMAINS OF THE CONVECTION IS DIMINISHING SLOWLY ACROSS THE
CENTRAL PART OF THE FORECAST AREA. EXPECT THIS TREND TO CONTINUE
THROUGH THE REMAINDER OF THE NIGHT. THE 01.05Z HRRR EVEN SUGGESTS
THE AREA WILL BE CLEAR OF ANY RAIN BY 12Z AND MAY NEED TO START
THE MORNING THAT WAY. AS THE DAY PROGRESSES...THE SURFACE LOW OVER
SOUTH DAKOTA MOVES ACROSS MINNESOTA INTO NORTHERN WISCONSIN AS THE
UPPER LEVEL LOW BECOMES AN OPEN WAVE. THE SHORT WAVE TROUGH SEEN
ON WATER VAPOR SATELLITE OVER SOUTH DAKOTA AND NEBRASKA WILL MOVE
ACROSS THE AREA. THE 01.00Z NAM INDICATES THIS WAVE WILL PRODUCE
UP TO 12 PVU/S OF VORTICITY ADVECTION IN THE 500-300 MB LAYER
DURING THE AFTERNOON. THE AREA WILL GET INTO THE DEFORMATION ON
THE BACK SIDE OF THE SURFACE LOW WITH SOME WEAK FRONTOGENESIS
DEVELOPING IN THE 1000-850 MB LAYER ALONG WITH SOME WEAK UP GLIDE
ON THE 295K SURFACE. THIS IS EXPECTED TO BE ENOUGH TO GENERATE
SOME SCATTERED SHOWERS DURING THE AFTERNOON AND WITH BETWEEN 200
AND 400 J/KG OF ML CAPE SOME ISOLATED THUNDERSTORMS SHOULD ALSO
DEVELOP. AS TEMPERATURES ALOFT COOL WITH THE PASSAGE OF THE UPPER
LEVEL TROUGH...THE FREEZING LEVEL WILL ALSO COME DOWN AND IF ANY
OF THE THUNDERSTORMS CAN DEVELOP A GOOD CORE ALOFT...SOME HAIL
WILL BE POSSIBLE. AS THE SYSTEM THEN MOVES AWAY FROM THE AREA
TONIGHT AND WITH THE LOSS OF THE CAPE...EXPECT THE ACTIVITY TO DIE
DOWN DURING THE EVENING WITH THE SHOWERS ENDING COMPLETELY AFTER
MIDNIGHT.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 321 AM CDT SAT JUN 1 2013
RIDGING ALOFT WILL BRIEFLY BUILD OVER THE UPPER MIDWEST FOR SUNDAY
AND MONDAY AND WITH HIGH PRESSURE AT THE SURFACE...A COUPLE OF DRY
DAYS ARE ANTICIPATED. THIS RIDGING THEN MOVES OFF AS ANOTHER
CLOSED UPPER LEVEL LOW APPROACHES FROM THE NORTHWEST. THIS SYSTEM
LOOKS TO BE ANOTHER SLOW MOVING SYSTEM AND WILL KEEP RAIN CHANCES
IN FOR AN EXTENDED TIME FROM MONDAY NIGHT THROUGH FRIDAY. UNLIKE
THE PAST SYSTEM...THIS ONE IS NOT EXPECTED TO PRODUCE NEARLY AS
MUCH HEAVY RAIN. THE 01.00Z GFS INDICATES PRECIPITABLE WATERS WITH
THIS SYSTEM WILL PRIMARILY BE IN THE 1 TO 1.25 INCH RANGE INSTEAD
OF 1.5 INCHES OR HIGHER AS WITH THE RECENT SYSTEM. ALSO...THE
01.00Z ECMWF SUGGESTS THAT AS THE SHORT WAVE TROUGHS ROTATE AROUND
THE UPPER LEVEL LOW...THE BULK OF THE FORCING WILL ACTUALLY BE
NORTH OF THE AREA FROM CENTRAL MINNESOTA AND NORTHWEST WISCONSIN
ON TO THE NORTH. ALSO NOT EXPECTING A LOT OF THUNDER FROM THIS
SYSTEM. NEITHER THE ECMWF OR GFS SHOW HARDLY ANY CAPE OVER THE AREA
FROM THIS SYSTEM AND THUS CUT THE THUNDER PROBABILITIES BACK TO
JUST HAVE ISOLATED AT BEST.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 647 AM CDT SAT JUN 1 2013
AN UPPER LEVEL LOW WILL MOVE EAST THROUGH THE AREA THIS AFTERNOON
AND TONIGHT. AS THIS OCCURS...A BROKEN DECK OF 3-5K DECK OF CLOUDS
WILL DEVELOP BY LATE THIS MORNING AND CONTINUE INTO THE AFTERNOON AT
BOTH TAF SITES. IN ADDITION TO THE LOWER CEILINGS...THERE WILL BE
ENOUGH INSTABILITY FOR SCATTERED SHOWERS AND ISOLATED
THUNDERSTORMS. AS THE LOW MOVES EAST OF THE AREA TONIGHT...
CEILINGS WILL BECOME MVFR AND THE WINDS WILL JUST OUT OF THE
NORTHWEST AT 20 TO 30 MPH.
&&
.HYDROLOGY...
ISSUED AT 321 AM CDT SAT JUN 1 2013
THE RAINS FROM FRIDAY EVENING HAVE CAUSED SOME RESPONSE ON SOME
AREA RIVERS. RISES HAVE BEEN OCCURRING ON THE WHITEWATER
RIVER...CEDAR RIVER IN OSAGE AND THE ROOT RIVER. ENOUGH RAIN FELL
ACROSS PARTS OF SOUTHEAST MINNESOTA AND NORTHEAST IOWA FOR
ADDITIONAL WITHIN BANK RISES TO OCCUR. EARLIER RAINS ARE STILL
EXPECTED TO PUSH PARTS OF THE MISSISSIPPI...BLACK...TREMPEALEAU
AND UPPER IOWA RIVERS NEAR OR OVER FLOOD STAGE. FOR ADDITIONAL
DETAILS...SEE THE LATEST RIVER FLOOD STATEMENTS.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...04
LONG TERM...04
AVIATION...BOYNE
HYDROLOGY...04
AREA FORECAST DISCUSSION
NWS TUCSON AZ
940 AM MST SAT JUN 1 2013
.SYNOPSIS...HIGH PRESSURE ANCHORED IN NORTHERN MEXICO WILL BRING
GENERALLY DRY AND HOT CONDITIONS TO SOUTHEAST ARIZONA INTO NEXT WEEK.
&&
.DISCUSSION...12Z KTWC SOUNDING SHOWING 1/2 INCH PRECIPITABLE WATER
MATCHING SATELLITE SOUNDER ESTIMATES WELL. TEMPERATURE PROFILE
SUPPORTS 103-105 FOR AN AFTERNOON HIGH AT TIA SO NO UPDATES NEEDED
THERE. HRRR ESTIMATES BETWEEN 1-2PM FOR CROSSING THE 100 THRESHOLD.
HIGH AMPLIFIES THROUGH NORTH CENTRAL MEXICO AS WE SEE WEAK
TROUGHINESS NEAR THE WEST COAST AND A STRONG LATE SEASON SYSTEM NEAR
THE PACIFIC NORTHWEST AND CANADIAN BORDER OVER THE NEXT 48 HOURS.
THE HIGH PRESSURE WILL BE OUR DOMINANT FEATURE BRINGING TEMPERATURES
ABOUT 10 DEGREES ABOVE CLIMO FOR SEVERAL DAYS. A FEW OF THE WEAKER
RECORD HIGHS COULD BE IN JEOPARDY SUNDAY AND MONDAY.
ECMWF AND LATEST NAMDNG5 STILL DIRTY UP THE NORTHERN AXIS OF
MEXICAN/DESERT SOUTHWEST RIDGE WITH A DECENT AMOUNT OF MID LEVEL
MOISTURE SUNDAY AFTERNOON AND EVENING. WE EXPECT ENOUGH OF THIS
TO SPILL OVER INTO OUR FAR EASTERN AREAS TO PUSH OUR CONVECTIVE
COVERAGE INTO THE ISOLATED RANGE EMPHASIZING MOUNTAIN LOCATIONS
CLOSER TO THE NEW MEXICO BORDER.
AS THIS HAPPENS A WEAK SOUTHERN BRANCH SPLIT DOWN THE COAST WILL
BRING SOME ENERGY TOWARD THE SOUTHERN CALIFORNIA COAST. A WEAK
CUT-OFF LINGERS MUCH OF THE WEEK WEST OF US AS THE HIGH PRESSURE
ANCHORED NEAR NORTHERN MEXICO CONTINUES TO DOMINATE OUR WEATHER.
ULTIMATELY IT WILL DRIFT EASTWARD AS STRONGER HIGH PRESSURE BUILDS
THROUGH THE EASTERN PACIFIC. AS THIS HAPPENS THERE WON`T BE MUCH
MOISTURE IN PLACE FOR IT TO WORK WITH...BUT A FEW MOUNTAIN BUILDUPS
NOT OUT OF THE QUESTION AGAIN LATER IN THE WEEK.
&&
.AVIATION...FEW-SCT CLOUDS AT 8-12K FT AGL MAINLY ACROSS THE WHITE
MOUNTAINS NE OF KSAD THIS AFTERNOON AND EARLY THIS EVENING.
OTHERWISE...SKC-SCT CLOUDS ABOVE 20K FT AGL THRU SUNDAY MORNING
OR 02/16Z. SURFACE WIND THIS AFTERNOON AND EARLY THIS EVENING
WLY/NWLY 10-15 KTS WITH GUSTS TO AROUND 20 KTS. OTHERWISE...SURFACE
WIND LESS THAN 10 KTS. AVIATION DISCUSSION NOT UPDATED FOR TAF
AMENDMENTS.
&&
.FIRE WEATHER...A FEW MAINLY DRY THUNDERSTORMS ARE POSSIBLE SUNDAY
AFTERNOON AND EARLY SUNDAY EVENING NEAR THE NEW MEXICO BORDER WITH
MOST OF THE THUNDERSTORM ACTIVITY OCCURRING FURTHER EAST IN NEW
MEXICO. OTHERWISE... DRY CONDITIONS WITH HOT DAYTIME TEMPERATURES
WILL PREVAIL INTO NEXT WEEK. DAYTIME MINIMUM RELATIVE HUMIDITIES
WILL GENERALLY BE IN THE SINGLE DIGITS TO LOWER TEENS WITH FAIR TO
POOR OVERNIGHT RECOVERIES. NORMAL DIURNAL WIND TRENDS WILL
OCCUR...WITH SOME GUSTINESS DURING THE AFTERNOON HOURS DUE TO STRONG
DAYTIME HEATING.
&&
.CLIMATE...THE MONTH OF MAY 2013 IS THE 10TH WARMEST MAY ON RECORD
FOR TUCSON. MEANWHILE...SPRING 2013 IS THE 2ND WARMEST SPRING ON
RECORD.
&&
.TWC WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...YOUTUBE...AND AT WEATHER.GOV/TUCSON
MEYER/RASMUSSEN
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
514 PM CDT SAT JUN 1 2013
.DISCUSSION...
308 PM CDT
CONVETIVE TRENDS ARE THE MAIN FORECAST ISSUE THIS AFTERNOON. WILL
MAINTAIN FLASH FLOOD WATCH ACROSS SOUTHERN TIER OF COUNTIES
THROUGH ITS 00Z EXPIRATION.
SURFACE LOW PRESSURE WAS CENTERED OVER CENTRAL WI AT MID
AFTERNOON...WITH A COLD FRONT EXTENDING SOUTH THROUGH THE
MISSISSIPPI RIVER VALLEY THEN SOUTHWEST ACROSS MISSOURI. DESPITE
CONSIDERABLE CLOUD COVER NORTHWEST/WEST CENTRAL IL HAS DESTABILIZED
AS EXPECTED THIS AFTERNOON...WITH SCATTERED SHRA/TSRA DEVELOPING
ACROSS THE UIN-PIA-PNT AT 19Z. SPC RAP MESOANALYSIS GUIDANCE
INDICATES AN AXIS OF 500-1000 J/KG AND GENERALLY CONVERGENT LOW
LEVEL FLOW IN THAT REGION AHEAD OF THE SFC COLD FRONT...AND EXPECT
THAT THIS ACTIVITY WILL CONTINUE TO DEVELOP AND SPREAD NORTHEAST
OVER THE NEXT SEVERAL HOURS AIDED BY LARGE SCALE ASCENT ASSOCIATED
WITH SHORT WAVE TROUGH PROPAGATING ACROSS IA/MO PER GOES WATER VAPOR
IMAGERY. SUCCESSIVE RUNS OF THE HRRR HAVE MAINTAINED THE IDEA OF
SCATTERED STORMS/SMALL CLUSTERS LIFTING NORTHEAST THROUGH THE
CHICAGO METRO AREA THROUGH 23-01Z OR SO...BEFORE DIURNAL DECREASE IN
INSTABILITY WITH SUNSET RESULTS IN DECREASE IN COVERAGE THIS
EVENING. WHILE WIDESPREAD SEVERE WEATHER IS NOT ANTICIPATED...WITH
EFFECTIVE BULK SHEAR APPROACHING 30 KT AND DRIER AIR ALOFT...MAINLY
WEST WHERE A DCAPE AXIS OF 600-800 J/KG IS ANALYZED...WE COULD SEE A
FEW OF THE STRONGEST CELLS PRODUCE A LITTLE HAIL OR WIND DURING THE
REMAINDER OF THE AFTERNOON HOURS. ORGANIZED HEAVY RAINFALL SEEMS A
FAIRLY LOW PROBABILITY AT THIS POINT...THOUGH ANALYSIS/GUIDANCE
CONTINUES TO DEPICT PWATS NEAR 1.5 INCHES...BETTER LOW LEVEL
MOISTURE TRANSPORT AND SLIGHTLY SLOWER STORM PROPAGATION POTENTIAL
ACROSS THE SOUTHEASTERN COUNTIES OF THE CWA. SINCE A FLASH FLOOD
WATCH IS ALREADY IN PLACE THERE...AND WITH THESE AREAS HAVING
RECEIVED BETWEEN 2-3 INCHES OF RAINFALL IN YESTERDAY/LAST NIGHTS
MCS/S...ILL ALLOW THE WATCH TO RUN THROUGH ITS 00Z EXPIRATION.
COLD FRONT AND MID-LEVEL TROUGH AXIS PUSH ACROSS THE CWA THIS
EVENING...WITH DRIER AIR AND HEIGHT RISES SPREADING IN FROM THE WEST
OVERNIGHT. WEAKER SECONDARY FRONT TRAILS ACROSS THE AREA SUNDAY
MORNING HOWEVER...WITH MOST GUIDANCE RUNS INDICATING THE POTENTIAL
FOR A FEW SPOTTY SHOWERS MAINLY ACROSS EAST/SOUTHEAST PARTS OF THE
FORECAST AREA. BEYOND THAT...SURFACE HIGH PRESSURE WILL BUILD INTO
THE AREA LATER SUNDAY THROUGH MONDAY MAKING FOR A COUPLE OF DAYS OF
DRY AND COOLER WEATHER WITH AFTERNOON LAKE BREEZES. GUIDANCE
REASONABLE IN DEPICTING TEMPS IN THE MID/UPPER 60S SUNDAY...AND MID
60S TO LOWER 70S MONDAY...WITH LOWER 60S LIKELY ALONG THE LAKE
MICHIGAN SHORES. LOWS ARE EXPECTED TO BE IN THE 40S IN MANY AREAS
AWAY FROM THE CHICAGO METRO SPRAWL SUNDAY NIGHT AND AGAIN MONDAY
NIGHT.
UPPER LEVEL RIDGE AXIS DEVELOPS ACROSS THE REGION INTO TUESDAY...
WHILE CLOSED UPPER LOW CURRENTLY OFF THE BRITISH COLUMBIA COAST
MAKES ITS WAY INTO THE NORTHERN PLAINS. AS THIS OCCURS...THE SFC
HIGH OVER THE WESTERN LAKES WILL DRIFT TO THE EAST...WITH LOW LEVEL
FLOW MORE SOUTH-SOUTHEAST ACROSS THE PLAINS AND MISSISSIPPI VALLEY
BY MID-WEEK. THIS RETURN FLOW AND ASSOCIATED WARM/MOIST ADVECTION
WILL INITIALLY FOCUS ACROSS THE PLAINS AND INTO IA/MN
TUESDAY/TUESDAY NIGHT...BUT WILL SHIFT FARTHER EAST AND BRING
SHRA/TSRA CHANCES BACK TO OUR AREA LATER TUESDAY NIGHT AND
WEDNESDAY. SOME GUIDANCE HINTS AT A FEW SHRA/TSRA MOVING INTO OUR
NORTHWEST COUNTIES TUESDAY AFTERNOON...THOUGH THESE SHOULD BE
DECAYING AS THEY MOVE OUT OF THE BETTER FORCING/MOISTURE WEST OF THE
MISSISSIPPI AND HAVE MAINTAINED DRY FORECAST THROUGH THE DAY TUESDAY
WITH LOW CONFIDENCE OF ANY PRECIP OF SIGNIFICANCE MAKING IT THIS FAR
EAST. SHRA/TSRA CHANCES THEN INCREASE WEDNESDAY THROUGH THURSDAY AS
UPPER LOW AND INVERTED SURFACE TROUGH/COLD FRONT MOVE ACROSS THE
AREA. UPPER LOW FILLS AND OPENS UP DURING THIS TIME...WITH SOUTH
WARM/MOIST ADVECTION FLOW NOT TERRIBLY STRONG. SUSPECT THERE WILL BE
MANY DRY HOURS BETWEEN CLUSTERS OF SHRA/TSRA DURING THIS PERIOD.
TEMPS MODERATE BACK INTO THE LOW-MID 70S/NEAR NORMAL DURING THE
MID-WEEK PERIOD...THOUGH SOUTHEAST SYNOPTIC WINDS WILL KEEP WINDS
OFF THE LAKE PARTICULARLY ACROSS NORTHEAST IL.
SURFACE COLD FRONT SETTLES SLOWLY OFF TO THE SOUTH/SOUTHEAST OF THE
CWA THURSDAY NIGHT...THOUGH UPPER TROUGH AXIS LINGERS ACROSS THE
REGION INTO NEXT WEEKEND. HAVE HELD ONTO SOME SLIGHT CHANCE POPS
FRIDAY WITH THE TROUGH AXIS OVERHEAD AND THE ECMWF CONTINUING TO
SQUEEZE OUT QPF...THOUGH DRIER LOW LEVEL FLOW AROUND SFC HIGH
PRESSURE OVER THE NORTHERN LAKES SHOULD HELP MAINTAIN GENERALLY DRY
CONDITIONS BY FRIDAY NIGHT/SATURDAY. TEMPS DURING THE PERIOD
EXPECTED TO BE NEAR NORMAL...70S...THOUGH ONSHORE WINDS OFF THE BIG
POND WILL KEEP CONDITIONS COOLER NEAR THE LAKE.
RATZER
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 22Z...
* TWO WAVES OF SHRA/ISOLD TSRA NOW THROUGH ABOUT 01Z
* OCNL MKVR CIGS THROUGH EARLY EVENING WITH BRIEF IFR VSBY IN
HEAVIER RAIN
* MVFR...POSSIBLE IFR...CIG DEVELOPING LATE TONIGHT/EARLY SUN
MORNING.
* WINDS SHIFT WITH LAKE BREEZE MID AFTERNOON SUN.
IZZI
//DISCUSSION...UPDATED 18Z...
MAIN FORECAST CONCERN IS THE POTENTIAL FOR A SCATTERED TO BROKEN
LINE OF SHOWERS AND THUNDERSTORMS TO DEVELOP OVER NORTHERN
ILLINOIS BY MID AFTERNOON AND SHIFT EAST INTO INDIANA EARLY THIS
EVENING. SCATTERED LIGHT SHOWERS MAY LINGER THROUGH THE EVENING.
WARM AND VERY MOIST LOWER ATMOSPHERE IS STILL IN PLACE ACROSS
NORTHERN IL AND NORTHWEST IN EARLY THIS AFTERNOON. EXTENSIVE CLOUD
COVER HAS LIMITED INSTABILITY OVER THE AREA BUT AS LOW PRESSURE
MOVES FROM WISCONSIN TO NORTHERN MICHIGAN...A COLD FRONT WILL MOVE
ACROSS THE AREA THIS EVENING. SHOWERS AND THUNDERSTORMS ARE
EXPECTED TO DEVELOP ALONG AND AHEAD OF THE FRONT. AFTER THE FRONT
PASSES...SOME LINGERING LIGHT SHOWERS MAY PERSISTS TO AROUND
MIDNIGHT.
WIDESPREAD MVFR CIGS IN THE WARM MOIST AIRMASS AHEAD OF THE FRONT
HAVE BEEN SLOWLY LIFTING THROUGH THE MORNING/EARLY AFTERNOON BUT
REMAIN MOSTLY BETWEEN 2-3 THOUSAND FEET. EXPECT THE MVFR CIGS TO
REMAIN THROUGH THE REST OF THE AFTERNOON AND EVENING. STRONG GUSTY
SOUTHWEST WINDS WILL DIMINISH THIS EVENING. THE INITIAL PRESSURE
TROF/FRONT WILL SHIFT WINDS TO WSW THIS EVENING. THE PUSH OF
COLDER AIR WILL COME WITH A SECONDARY FRONT LATE TONIGHT. THIS
WILL TURN WINDS WNW. GUIDANCE SUGGESTS SOME IFR OR EVEN LOW IFR
CIGS TO DEVELOP LATE TONIGHT OR TOWARD MORNING. LIFR WOULD BE RARE
FOR JUNE BUT HAVE ADDED A TEMPO IFR CIG GROUP TO THE TAFS. CIGS
SHOULD LIFT SUNDAY MORNING AS STRONG NORTHWEST WINDS BEGIN MIXING
IN COOLER DRIER AIR.
A LAKE BREEZE MAY DEVELOP BY MID OR LATE AFTERNOON SUNDAY AND WILL
LIKELY REFLECT THIS IN LATER TAF ISSUANCES.
ALLSOPP
//ORD AND MDW CONFIDENCE...UPDATED 22Z...
* MEDIUM-HIGH CONFIDENCE IN SCT-BKN AREA OF SHOWERS AND A FEW
THUNDERSTORMS REST OF THE AFTN INTO EARLY EVENING.
* MEDIUM CONFIDENCE IN CIG TRENDS. LOW CONFIDENCE IN IFR
DEVELOPING LATE TONIGHT.
* MEDIUM-HIGH CONFIDENCE IN WIND FORECAST.
ALLSOPP/IZZI
//OUTLOOK FOR ORD/MDW FOR 00Z MONDAY-12Z SATURDAY...UPDATED 12Z...
SUNDAY NIGHT-TUESDAY...MAINLY VFR.
WEDNESDAY-FRIDAY...CHC OF TSRA.
MTF
&&
.MARINE...
218 PM CDT
MODERATE SOUTHERLY WINDS ARE OCCURRING AHEAD OF AN AREA OF LOW
PRESSURE AND ITS ATTENDANT COLD FRONT WHICH ARE EXPECTED TO PASS
OVER THE LAKE TONIGHT. A BRIEF LULL IN THE WINDS MAY OCCUR WITH THE
FRONTAL TROUGH THIS EVENING...BUT THEN WINDS ARE EXPECTED TO
SHIFT TO NORTHWESTERLY AND RAMP BACK UP INTO THE 20 TO 25 KT RANGE
FOR MUCH OF THE LAKE OVERNIGHT. WINDS SHOULD COME DOWN THROUGH
THE DAY SUNDAY...REMAINING RELATIVELY LIGHT ON MONDAY WITH LAKE
BREEZES DEVELOPING. ANOTHER AREA OF LOW PRESSURE BEGINS TO TAKE
SHAPE OVER THE PLAINS LATE MONDAY INTO TUESDAY WITH SOUTHEASTERLY
WINDS FRESHENING UP TO PERHAPS 15 TO 20 KT AT TIMES THROUGH
THURSDAY. THURSDAY NIGHT...THE LOW WEAKENS AS IT PASSES SOUTH OF
THE LAKE WITH WINDS TURNING NORTHERLY FRIDAY THROUGH THE WEEKEND.
BMD
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...FLASH FLOOD WATCH...ILZ032-ILZ033-ILZ039 UNTIL 7 PM SATURDAY.
IN...FLASH FLOOD WATCH...INZ010-INZ011-INZ019 UNTIL 7 PM SATURDAY.
LM...DENSE FOG ADVISORY...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565
UNTIL 9 PM SATURDAY.
&&
$$
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AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
310 PM CDT SAT JUN 1 2013
.DISCUSSION...
308 PM CDT
CONVETIVE TRENDS ARE THE MAIN FORECAST ISSUE THIS AFTERNOON. WILL
MAINTAIN FLASH FLOOD WATCH ACROSS SOUTHERN TIER OF COUNTIES
THROUGH ITS 00Z EXPIRATION.
SURFACE LOW PRESSURE WAS CENTERED OVER CENTRAL WI AT MID
AFTERNOON...WITH A COLD FRONT EXTENDING SOUTH THROUGH THE
MISSISSIPPI RIVER VALLEY THEN SOUTHWEST ACROSS MISSOURI. DESPITE
CONSIDERABLE CLOUD COVER NORTHWEST/WEST CENTRAL IL HAS DESTABILIZED
AS EXPECTED THIS AFTERNOON...WITH SCATTERED SHRA/TSRA DEVELOPING
ACROSS THE UIN-PIA-PNT AT 19Z. SPC RAP MESOANALYSIS GUIDANCE
INDICATES AN AXIS OF 500-1000 J/KG AND GENERALLY CONVERGENT LOW
LEVEL FLOW IN THAT REGION AHEAD OF THE SFC COLD FRONT...AND EXPECT
THAT THIS ACTIVITY WILL CONTINUE TO DEVELOP AND SPREAD NORTHEAST
OVER THE NEXT SEVERAL HOURS AIDED BY LARGE SCALE ASCENT ASSOCIATED
WITH SHORT WAVE TROUGH PROPAGATING ACROSS IA/MO PER GOES WATER VAPOR
IMAGERY. SUCCESSIVE RUNS OF THE HRRR HAVE MAINTAINED THE IDEA OF
SCATTERED STORMS/SMALL CLUSTERS LIFTING NORTHEAST THROUGH THE
CHICAGO METRO AREA THROUGH 23-01Z OR SO...BEFORE DIURNAL DECREASE IN
INSTABILITY WITH SUNSET RESULTS IN DECREASE IN COVERAGE THIS
EVENING. WHILE WIDESPREAD SEVERE WEATHER IS NOT ANTICIPATED...WITH
EFFECTIVE BULK SHEAR APPROACHING 30 KT AND DRIER AIR ALOFT...MAINLY
WEST WHERE A DCAPE AXIS OF 600-800 J/KG IS ANALYZED...WE COULD SEE A
FEW OF THE STRONGEST CELLS PRODUCE A LITTLE HAIL OR WIND DURING THE
REMAINDER OF THE AFTERNOON HOURS. ORGANIZED HEAVY RAINFALL SEEMS A
FAIRLY LOW PROBABILITY AT THIS POINT...THOUGH ANALYSIS/GUIDANCE
CONTINUES TO DEPICT PWATS NEAR 1.5 INCHES...BETTER LOW LEVEL
MOISTURE TRANSPORT AND SLIGHTLY SLOWER STORM PROPAGATION POTENTIAL
ACROSS THE SOUTHEASTERN COUNTIES OF THE CWA. SINCE A FLASH FLOOD
WATCH IS ALREADY IN PLACE THERE...AND WITH THESE AREAS HAVING
RECEIVED BETWEEN 2-3 INCHES OF RAINFALL IN YESTERDAY/LAST NIGHTS
MCS/S...ILL ALLOW THE WATCH TO RUN THROUGH ITS 00Z EXPIRATION.
COLD FRONT AND MID-LEVEL TROUGH AXIS PUSH ACROSS THE CWA THIS
EVENING...WITH DRIER AIR AND HEIGHT RISES SPREADING IN FROM THE WEST
OVERNIGHT. WEAKER SECONDARY FRONT TRAILS ACROSS THE AREA SUNDAY
MORNING HOWEVER...WITH MOST GUIDANCE RUNS INDICATING THE POTENTIAL
FOR A FEW SPOTTY SHOWERS MAINLY ACROSS EAST/SOUTHEAST PARTS OF THE
FORECAST AREA. BEYOND THAT...SURFACE HIGH PRESSURE WILL BUILD INTO
THE AREA LATER SUNDAY THROUGH MONDAY MAKING FOR A COUPLE OF DAYS OF
DRY AND COOLER WEATHER WITH AFTERNOON LAKE BREEZES. GUIDANCE
REASONABLE IN DEPICTING TEMPS IN THE MID/UPPER 60S SUNDAY...AND MID
60S TO LOWER 70S MONDAY...WITH LOWER 60S LIKELY ALONG THE LAKE
MICHIGAN SHORES. LOWS ARE EXPECTED TO BE IN THE 40S IN MANY AREAS
AWAY FROM THE CHICAGO METRO SPRAWL SUNDAY NIGHT AND AGAIN MONDAY
NIGHT.
UPPER LEVEL RIDGE AXIS DEVELOPS ACROSS THE REGION INTO TUESDAY...
WHILE CLOSED UPPER LOW CURRENTLY OFF THE BRITISH COLUMBIA COAST
MAKES ITS WAY INTO THE NORTHERN PLAINS. AS THIS OCCURS...THE SFC
HIGH OVER THE WESTERN LAKES WILL DRIFT TO THE EAST...WITH LOW LEVEL
FLOW MORE SOUTH-SOUTHEAST ACROSS THE PLAINS AND MISSISSIPPI VALLEY
BY MID-WEEK. THIS RETURN FLOW AND ASSOCIATED WARM/MOIST ADVECTION
WILL INITIALLY FOCUS ACROSS THE PLAINS AND INTO IA/MN
TUESDAY/TUESDAY NIGHT...BUT WILL SHIFT FARTHER EAST AND BRING
SHRA/TSRA CHANCES BACK TO OUR AREA LATER TUESDAY NIGHT AND
WEDNESDAY. SOME GUIDANCE HINTS AT A FEW SHRA/TSRA MOVING INTO OUR
NORTHWEST COUNTIES TUESDAY AFTERNOON...THOUGH THESE SHOULD BE
DECAYING AS THEY MOVE OUT OF THE BETTER FORCING/MOISTURE WEST OF THE
MISSISSIPPI AND HAVE MAINTAINED DRY FORECAST THROUGH THE DAY TUESDAY
WITH LOW CONFIDENCE OF ANY PRECIP OF SIGNIFICANCE MAKING IT THIS FAR
EAST. SHRA/TSRA CHANCES THEN INCREASE WEDNESDAY THROUGH THURSDAY AS
UPPER LOW AND INVERTED SURFACE TROUGH/COLD FRONT MOVE ACROSS THE
AREA. UPPER LOW FILLS AND OPENS UP DURING THIS TIME...WITH SOUTH
WARM/MOIST ADVECTION FLOW NOT TERRIBLY STRONG. SUSPECT THERE WILL BE
MANY DRY HOURS BETWEEN CLUSTERS OF SHRA/TSRA DURING THIS PERIOD.
TEMPS MODERATE BACK INTO THE LOW-MID 70S/NEAR NORMAL DURING THE
MID-WEEK PERIOD...THOUGH SOUTHEAST SYNOPTIC WINDS WILL KEEP WINDS
OFF THE LAKE PARTICULARLY ACROSS NORTHEAST IL.
SURFACE COLD FRONT SETTLES SLOWLY OFF TO THE SOUTH/SOUTHEAST OF THE
CWA THURSDAY NIGHT...THOUGH UPPER TROUGH AXIS LINGERS ACROSS THE
REGION INTO NEXT WEEKEND. HAVE HELD ONTO SOME SLIGHT CHANCE POPS
FRIDAY WITH THE TROUGH AXIS OVERHEAD AND THE ECMWF CONTINUING TO
SQUEEZE OUT QPF...THOUGH DRIER LOW LEVEL FLOW AROUND SFC HIGH
PRESSURE OVER THE NORTHERN LAKES SHOULD HELP MAINTAIN GENERALLY DRY
CONDITIONS BY FRIDAY NIGHT/SATURDAY. TEMPS DURING THE PERIOD
EXPECTED TO BE NEAR NORMAL...70S...THOUGH ONSHORE WINDS OFF THE BIG
POND WILL KEEP CONDITIONS COOLER NEAR THE LAKE.
RATZER
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 20Z...
* SCT-BKN AREA OF SHOWERS AND THUNDERSTORMS OVERSPREADING
NORTHEAST IL/NORTHWEST IN THIS AFTN AND EARLY EVE.
* MVFR CIGS THIS AFTN INTO EARLY EVE IMPROVING TO VFR THIS EVE.
* STRONG GUSTY SW WINDS DIMINISHING THIS EVE AND BECOMING
WEST...THEN SHIFTING NW TOWARD MORNING.
* MVFR...POSSIBLE IFR...CIG DEVELOPING LATE TONIGHT/EARLY SUN
MORNING.
* LAKE BREEZE MID AFTERNOON SUN.
ALLSOPP
//DISCUSSION...UPDATED 18Z...
MAIN FORECAST CONCERN IS THE POTENTIAL FOR A SCATTERED TO BROKEN
LINE OF SHOWERS AND THUNDERSTORMS TO DEVELOP OVER NORTHERN
ILLINOIS BY MID AFTERNOON AND SHIFT EAST INTO INDIANA EARLY THIS
EVENING. SCATTERED LIGHT SHOWERS MAY LINGER THROUGH THE EVENING.
WARM AND VERY MOIST LOWER ATMOSPHERE IS STILL IN PLACE ACROSS
NORTHERN IL AND NORTHWEST IN EARLY THIS AFTERNOON. EXTENSIVE CLOUD
COVER HAS LIMITED INSTABILITY OVER THE AREA BUT AS LOW PRESSURE
MOVES FROM WISCONSIN TO NORTHERN MICHIGAN...A COLD FRONT WILL MOVE
ACROSS THE AREA THIS EVENING. SHOWERS AND THUNDERSTORMS ARE
EXPECTED TO DEVELOP ALONG AND AHEAD OF THE FRONT. AFTER THE FRONT
PASSES...SOME LINGERING LIGHT SHOWERS MAY PERSISTS TO AROUND
MIDNIGHT.
WIDESPREAD MVFR CIGS IN THE WARM MOIST AIRMASS AHEAD OF THE FRONT
HAVE BEEN SLOWLY LIFTING THROUGH THE MORNING/EARLY AFTERNOON BUT
REMAIN MOSTLY BETWEEN 2-3 THOUSAND FEET. EXPECT THE MVFR CIGS TO
REMAIN THROUGH THE REST OF THE AFTERNOON AND EVENING. STRONG GUSTY
SOUTHWEST WINDS WILL DIMINISH THIS EVENING. THE INITIAL PRESSURE
TROF/FRONT WILL SHIFT WINDS TO WSW THIS EVENING. THE PUSH OF
COLDER AIR WILL COME WITH A SECONDARY FRONT LATE TONIGHT. THIS
WILL TURN WINDS WNW. GUIDANCE SUGGESTS SOME IFR OR EVEN LOW IFR
CIGS TO DEVELOP LATE TONIGHT OR TOWARD MORNING. LIFR WOULD BE RARE
FOR JUNE BUT HAVE ADDED A TEMPO IFR CIG GROUP TO THE TAFS. CIGS
SHOULD LIFT SUNDAY MORNING AS STRONG NORTHWEST WINDS BEGIN MIXING
IN COOLER DRIER AIR.
A LAKE BREEZE MAY DEVELOP BY MID OR LATE AFTERNOON SUNDAY AND WILL
LIKELY REFLECT THIS IN LATER TAF ISSUANCES.
ALLSOPP
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
* MEDIUM-HIGH CONFIDENCE IN SCT-BKN AREA OF SHOWERS AND A FEW
THUNDERSTORMS REST OF THE AFTN INTO EARLY EVENING.
* MEDIUM CONFIDENCE IN CIG TRENDS. LOW CONFIDENCE IN IFR
DEVELOPING LATE TONIGHT.
* MEDIUM-HIGH CONFIDENCE IN WIND FORECAST.
ALLSOPP
//OUTLOOK FOR ORD/MDW FOR 00Z MONDAY-12Z SATURDAY...UPDATED 12Z...
SUNDAY NIGHT-TUESDAY...MAINLY VFR.
WEDNESDAY-FRIDAY...CHC OF TSRA.
MTF
&&
.MARINE...
218 PM CDT
MODERATE SOUTHERLY WINDS ARE OCCURRING AHEAD OF AN AREA OF LOW
PRESSURE AND ITS ATTENDANT COLD FRONT WHICH ARE EXPECTED TO PASS
OVER THE LAKE TONIGHT. A BRIEF LULL IN THE WINDS MAY OCCUR WITH THE
FRONTAL TROUGH THIS EVENING...BUT THEN WINDS ARE EXPECTED TO
SHIFT TO NORTHWESTERLY AND RAMP BACK UP INTO THE 20 TO 25 KT RANGE
FOR MUCH OF THE LAKE OVERNIGHT. WINDS SHOULD COME DOWN THROUGH
THE DAY SUNDAY...REMAINING RELATIVELY LIGHT ON MONDAY WITH LAKE
BREEZES DEVELOPING. ANOTHER AREA OF LOW PRESSURE BEGINS TO TAKE
SHAPE OVER THE PLAINS LATE MONDAY INTO TUESDAY WITH SOUTHEASTERLY
WINDS FRESHENING UP TO PERHAPS 15 TO 20 KT AT TIMES THROUGH
THURSDAY. THURSDAY NIGHT...THE LOW WEAKENS AS IT PASSES SOUTH OF
THE LAKE WITH WINDS TURNING NORTHERLY FRIDAY THROUGH THE WEEKEND.
BMD
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...FLASH FLOOD WATCH...ILZ032-ILZ033-ILZ039 UNTIL 7 PM SATURDAY.
IN...FLASH FLOOD WATCH...INZ010-INZ011-INZ019 UNTIL 7 PM SATURDAY.
LM...DENSE FOG ADVISORY...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565
UNTIL 9 PM SATURDAY.
SMALL CRAFT ADVISORY...NEARSHORE WATERS
UNTIL 4 PM 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
250 PM CDT SAT JUN 1 2013
.DISCUSSION...
1141 AM CDT
FOR MORNING UPDATE...
HAVE MADE SOME CHANGES TO POP COVERAGE/TIMING THROUGH THIS
AFTERNOON...AND HAVE TRIMMED THE NORTHERN TIER OF COUNTIES FROM THE
FLASH FLOOD WATCH.
SFC LOW PRESSURE WAS OVER THE UPPER MISSISSIPPI VALLEY THIS
MORNING...ASSOCIATED WITH UPPER TROUGH/LOW OVER MINNESOTA. SURFACE
COLD FRONT EXTENDS SOUTH FROM THE LOW ALONG THE MISSISSIPPI RIVER
AND THEN SOUTHWEST ACROSS CENTRAL MO. WHILE FORECAST AREA REMAINS IN
WARM/MOIST SOUTH FLOW AHEAD OF THE COLD FRONT...COMBINED OUTFLOW
FROM SERIES OF THUNDERSTORM COMPLEXES HAS PUSHED SOUTH OF THE OHIO
RIVER WITH MOSTLY CLOUDY/SLIGHTLY DRIER LOW LEVEL AIR IN PLACE
ACROSS NORTHERN IL/NORTHWEST INDIANA. THIS WILL VERY LIKELY SHIFT
THE FOCUS OF GREATER HEAVY RAIN/SEVERE THREAT SOUTH OF THE CWA FOR
THE REMAINDER OF THE AFTERNOON/EVENING. ACCORDINGLY...HAVE CANCELLED
PORTION OF FLASH FLOOD WATCH...KEEPING ONLY SOUTH TIER WHERE 2-3
INCH RAINS OCCURRED YESTERDAY AFTERNOON/EVENING. THIS AREA ALSO MORE
FAVORED FOR THE OF POTENTIAL LOCALIZED HEAVIER RAINFALL LATE THIS
AFTERNOON/EARLY EVENING...WITH HIGHER PWATS/STRONGER 850 MB MOIST
TRANSPORT AND SLOWER EXPECTED STORM PROPAGATION ACROSS THE
SOUTHEASTERN CWA.
WHILE OVERALL THREAT/COVERAGE OF TSRA APPEARS TO BE
DIMINISHED...MORNING RAOB ANALYSIS AND WATER VAPOR IMAGERY DOES
DEPICT A SHORT WAVE TROUGH ACROSS NORTHERN MISSOURI WHICH WILL LIFT
NORTHEAST INTO NORTHERN IL THIS AFTERNOON. 12Z SOUNDING FROM DVN
INDICATES INVERSION WAS FAIRLY SHALLOW ACROSS THE WEST/NORTHWEST
PARTS OF THE FA...WHICH COMBINED WITH LOW LEVEL CONVERGENCE AHEAD OF
THE COLD FRONT AND LARGER SCALE ASCENT WITH APPROACHING SHORT WAVE
IS EXPECTED TO YIELD AROUND 800 J/KG MLCAPE WITH LITTLE/NO CIN BY
MID AFTERNOON HOURS. MORNING RUNS OF THE HRRR SUGGEST
ISOLATED/SCATTERED SHRA/TSRA DEVELOPMENT OVER WESTERN/NORTHWESTERN
IL WHICH WOULD THEN SHIFT EAST-NORTHEAST ACROSS THE CWA DURING LATER
AFTERNOON AND EARLY EVENING HOURS AHEAD OF THE COLD FRONT. VIS
SATELLITE DOES DEPICT SOME ENHANCED CU ACROSS FAR NW IL AHEAD OF THE
FRONT AT THIS TIME. WHILE SPC HAS SHIFTED DAY 1 SEVERE SLIGHT RISK
WELL EAST/SOUTH OF THE CWA...DRIER AIR AND STEEPER LAPSE RATES ALOFT
PER 12Z DVN SOUNDING SUGGESTS THERE COULD BE AN ISOLATED NEAR SEVERE
WIND/HAIL THREAT OVER NORTHERN IL THIS AFTERNOON. FARTHER
SOUTHEAST...12Z SOUNDING FROM ILX INDICATES A DEEPER STABLE LAYER
NEAR THE SURFACE...WITH WARMER TEMPS IN THE 850-700 MB LAYER LIKELY
KEEPING THINGS MORE CAPPED ACROSS OUR SOUTHEAST.
PER ABOVE REASONING...HAVE ELIMINATED MORNING POPS ACROSS THE CWA...
AND LOWERED POPS ACROSS THE SOUTHEAST THIS AFTERNOON. ALSO BUMPED
TEMPS A DEGREE OR TWO IN MOST AREAS.
RATZER
//PREV DISCUSSION...
326 AM...MAIN FORECAST CONCERN REMAINS CONVECTIVE TRENDS AND
HEAVY RAIN POTENTIAL INTO THIS EVENING...MAINLY OVER THE SOUTHEAST
HALF/THIRD OF THE CWA.
UPPER TROUGH FINALLY STARTS TO SHIFT NORTHEAST ACROSS THE UPPER
MIDWEST/LAKES REGION TODAY AND TONIGHT. NEXT SHORTWAVE THAT LIFTS
NORTHEAST LATER TODAY INTO THIS AFTERNOON EXPECTED TO BE A LITTLE
FURTHER EAST AFFECTING AREAS GENERALLY EAST OF THE I-55 CORRIDOR
AND THERE HAS BEEN REASONABLE CONSISTENCY WITH THIS TREND OVER THE
PAST DAY OR SO. THOUGH INSTABILITY FURTHER NORTHWEST STILL
SUFFICIENT TO FOR AT LEAST ISOLATED ACTIVITY THIS AFTERNOON INTO
THIS EVENING. BUT THE THREAT OF ANY SEVERE WEATHER SHOULD BE
PRIMARILY EAST OF I-55 WITH THE MAIN THREAT AGAIN DAMAGING WIND
GUSTS. IN ADDITION...HEAVY RAIN FALLING OVER THE SAME AREAS THAT
RECEIVED HEAVY RAIN FRIDAY NIGHT WILL ONLY INCREASE THE THREAT FOR
FLASH FLOODING...THUS NO CHANGES TO THE CURRENT FLASH FLOOD WATCH.
TIMING THOUGH REMAINS SOMEWHAT UNCERTAIN AS THIS MORNING COULD
END UP BEING FAIRLY DRY/QUIET WITH CONVECTION NOT FIRING UNTIL
EARLY/MID AFTERNOON...THEN QUICKLY SHIFTING EAST.
A WEAK WAVE ROTATES ACROSS THE AREA LATE TONIGHT INTO SUNDAY
MORNING AND SOME SHOWERS ARE POSSIBLE. THEN COOLER AIR SPREADS
ACROSS THE AREA SUNDAY NIGHT INTO MONDAY AS BROAD/WEAK HIGH
PRESSURE BUILDS ACROSS THE REGION. LOWS SUNDAY NIGHT COULD EASILY
DROP WELL INTO THE 40S WITH EXPECTED LIGHT WINDS. COULD BE SOME
CLOUDS AROUND BUT WITH AN EXPECTED LAKE BREEZE SUNDAY AFTERNOON
ALLOWING COOLED LAKE AIR TO FLOW INLAND...THINK COOLER IS BETTER
FOR LOWS BY MONDAY MORNING. AIRMASS WARMS SLIGHTLY ALONG WITH THE
POTENTIAL FOR SOME CLOUDS MONDAY NIGHT INTO TUESDAY MORNING...BUT
LOWS IN THE UPPER 40S LOOK ON TRACK BY TUESDAY MORNING. PREVAILING
EASTERLY FLOW WILL KEEP THE LAKESHORE AREAS COOLER FOR HIGHS
THROUGH MID WEEK BUT WITH EARLY JUNE SUNSHINE...THINK LOWER 70S
WELL INLAND WOULD BE REACHABLE.
CONFIDENCE REGARDING POPS MID/LATE NEXT WEEK IS FAIRLY LOW AS
ANOTHER UPPER LOW MOVES ACROSS THE PLAINS. WHILE SOMEWHAT
PROGRESSIVE...HOW FAR EAST VARIOUS PRECIP WAVES REACH IS DOUBTFUL
FROM THIS DISTANCE. STILL HAVE CHANCE POPS BY TUESDAY NIGHT BUT
FURTHER REFINEMENT WILL BE NEEDED WITH LATER FORECASTS. CMS
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 20Z...
* SCT-BKN AREA OF SHOWERS AND THUNDERSTORMS OVERSPREADING
NORTHEAST IL/NORTHWEST IN THIS AFTN AND EARLY EVE.
* MVFR CIGS THIS AFTN INTO EARLY EVE IMPROVING TO VFR THIS EVE.
* STRONG GUSTY SW WINDS DIMINISHING THIS EVE AND BECOMING
WEST...THEN SHIFTING NW TOWARD MORNING.
* MVFR...POSSIBLE IFR...CIG DEVELOPING LATE TONIGHT/EARLY SUN
MORNING.
* LAKE BREEZE MID AFTERNOON SUN.
ALLSOPP
//DISCUSSION...UPDATED 18Z...
MAIN FORECAST CONCERN IS THE POTENTIAL FOR A SCATTERED TO BROKEN
LINE OF SHOWERS AND THUNDERSTORMS TO DEVELOP OVER NORTHERN
ILLINOIS BY MID AFTERNOON AND SHIFT EAST INTO INDIANA EARLY THIS
EVENING. SCATTERED LIGHT SHOWERS MAY LINGER THROUGH THE EVENING.
WARM AND VERY MOIST LOWER ATMOSPHERE IS STILL IN PLACE ACROSS
NORTHERN IL AND NORTHWEST IN EARLY THIS AFTERNOON. EXTENSIVE CLOUD
COVER HAS LIMITED INSTABILITY OVER THE AREA BUT AS LOW PRESSURE
MOVES FROM WISCONSIN TO NORTHERN MICHIGAN...A COLD FRONT WILL MOVE
ACROSS THE AREA THIS EVENING. SHOWERS AND THUNDERSTORMS ARE
EXPECTED TO DEVELOP ALONG AND AHEAD OF THE FRONT. AFTER THE FRONT
PASSES...SOME LINGERING LIGHT SHOWERS MAY PERSISTS TO AROUND
MIDNIGHT.
WIDESPREAD MVFR CIGS IN THE WARM MOIST AIRMASS AHEAD OF THE FRONT
HAVE BEEN SLOWLY LIFTING THROUGH THE MORNING/EARLY AFTERNOON BUT
REMAIN MOSTLY BETWEEN 2-3 THOUSAND FEET. EXPECT THE MVFR CIGS TO
REMAIN THROUGH THE REST OF THE AFTERNOON AND EVENING. STRONG GUSTY
SOUTHWEST WINDS WILL DIMINISH THIS EVENING. THE INITIAL PRESSURE
TROF/FRONT WILL SHIFT WINDS TO WSW THIS EVENING. THE PUSH OF
COLDER AIR WILL COME WITH A SECONDARY FRONT LATE TONIGHT. THIS
WILL TURN WINDS WNW. GUIDANCE SUGGESTS SOME IFR OR EVEN LOW IFR
CIGS TO DEVELOP LATE TONIGHT OR TOWARD MORNING. LIFR WOULD BE RARE
FOR JUNE BUT HAVE ADDED A TEMPO IFR CIG GROUP TO THE TAFS. CIGS
SHOULD LIFT SUNDAY MORNING AS STRONG NORTHWEST WINDS BEGIN MIXING
IN COOLER DRIER AIR.
A LAKE BREEZE MAY DEVELOP BY MID OR LATE AFTERNOON SUNDAY AND WILL
LIKELY REFLECT THIS IN LATER TAF ISSUANCES.
ALLSOPP
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
* MEDIUM-HIGH CONFIDENCE IN SCT-BKN AREA OF SHOWERS AND A FEW
THUNDERSTORMS REST OF THE AFTN INTO EARLY EVENING.
* MEDIUM CONFIDENCE IN CIG TRENDS. LOW CONFIDENCE IN IFR
DEVELOPING LATE TONIGHT.
* MEDIUM-HIGH CONFIDENCE IN WIND FORECAST.
ALLSOPP
//OUTLOOK FOR ORD/MDW FOR 00Z MONDAY-12Z SATURDAY...UPDATED 12Z...
SUNDAY NIGHT-TUESDAY...MAINLY VFR.
WEDNESDAY-FRIDAY...CHC OF TSRA.
MTF
&&
.MARINE...
218 PM CDT
MODERATE SOUTHERLY WINDS ARE OCCURRING AHEAD OF AN AREA OF LOW
PRESSURE AND ITS ATTENDANT COLD FRONT WHICH ARE EXPECTED TO PASS
OVER THE LAKE TONIGHT. A BRIEF LULL IN THE WINDS MAY OCCUR WITH THE
FRONTAL TROUGH THIS EVENING...BUT THEN WINDS ARE EXPECTED TO
SHIFT TO NORTHWESTERLY AND RAMP BACK UP INTO THE 20 TO 25 KT RANGE
FOR MUCH OF THE LAKE OVERNIGHT. WINDS SHOULD COME DOWN THROUGH
THE DAY SUNDAY...REMAINING RELATIVELY LIGHT ON MONDAY WITH LAKE
BREEZES DEVELOPING. ANOTHER AREA OF LOW PRESSURE BEGINS TO TAKE
SHAPE OVER THE PLAINS LATE MONDAY INTO TUESDAY WITH SOUTHEASTERLY
WINDS FRESHENING UP TO PERHAPS 15 TO 20 KT AT TIMES THROUGH
THURSDAY. THURSDAY NIGHT...THE LOW WEAKENS AS IT PASSES SOUTH OF
THE LAKE WITH WINDS TURNING NORTHERLY FRIDAY THROUGH THE WEEKEND.
BMD
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...FLASH FLOOD WATCH...ILZ032-ILZ033-ILZ039 UNTIL 7 PM SATURDAY.
IN...FLASH FLOOD WATCH...INZ010-INZ011-INZ019 UNTIL 7 PM SATURDAY.
LM...DENSE FOG ADVISORY...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565
UNTIL 9 PM SATURDAY.
SMALL CRAFT ADVISORY...NEARSHORE WATERS
UNTIL 4 PM 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
219 PM CDT SAT JUN 1 2013
.DISCUSSION...
1141 AM CDT
FOR MORNING UPDATE...
HAVE MADE SOME CHANGES TO POP COVERAGE/TIMING THROUGH THIS
AFTERNOON...AND HAVE TRIMMED THE NORTHERN TIER OF COUNTIES FROM THE
FLASH FLOOD WATCH.
SFC LOW PRESSURE WAS OVER THE UPPER MISSISSIPPI VALLEY THIS
MORNING...ASSOCIATED WITH UPPER TROUGH/LOW OVER MINNESOTA. SURFACE
COLD FRONT EXTENDS SOUTH FROM THE LOW ALONG THE MISSISSIPPI RIVER
AND THEN SOUTHWEST ACROSS CENTRAL MO. WHILE FORECAST AREA REMAINS IN
WARM/MOIST SOUTH FLOW AHEAD OF THE COLD FRONT...COMBINED OUTFLOW
FROM SERIES OF THUNDERSTORM COMPLEXES HAS PUSHED SOUTH OF THE OHIO
RIVER WITH MOSTLY CLOUDY/SLIGHTLY DRIER LOW LEVEL AIR IN PLACE
ACROSS NORTHERN IL/NORTHWEST INDIANA. THIS WILL VERY LIKELY SHIFT
THE FOCUS OF GREATER HEAVY RAIN/SEVERE THREAT SOUTH OF THE CWA FOR
THE REMAINDER OF THE AFTERNOON/EVENING. ACCORDINGLY...HAVE CANCELLED
PORTION OF FLASH FLOOD WATCH...KEEPING ONLY SOUTH TIER WHERE 2-3
INCH RAINS OCCURRED YESTERDAY AFTERNOON/EVENING. THIS AREA ALSO MORE
FAVORED FOR THE OF POTENTIAL LOCALIZED HEAVIER RAINFALL LATE THIS
AFTERNOON/EARLY EVENING...WITH HIGHER PWATS/STRONGER 850 MB MOIST
TRANSPORT AND SLOWER EXPECTED STORM PROPAGATION ACROSS THE
SOUTHEASTERN CWA.
WHILE OVERALL THREAT/COVERAGE OF TSRA APPEARS TO BE
DIMINISHED...MORNING RAOB ANALYSIS AND WATER VAPOR IMAGERY DOES
DEPICT A SHORT WAVE TROUGH ACROSS NORTHERN MISSOURI WHICH WILL LIFT
NORTHEAST INTO NORTHERN IL THIS AFTERNOON. 12Z SOUNDING FROM DVN
INDICATES INVERSION WAS FAIRLY SHALLOW ACROSS THE WEST/NORTHWEST
PARTS OF THE FA...WHICH COMBINED WITH LOW LEVEL CONVERGENCE AHEAD OF
THE COLD FRONT AND LARGER SCALE ASCENT WITH APPROACHING SHORT WAVE
IS EXPECTED TO YIELD AROUND 800 J/KG MLCAPE WITH LITTLE/NO CIN BY
MID AFTERNOON HOURS. MORNING RUNS OF THE HRRR SUGGEST
ISOLATED/SCATTERED SHRA/TSRA DEVELOPMENT OVER WESTERN/NORTHWESTERN
IL WHICH WOULD THEN SHIFT EAST-NORTHEAST ACROSS THE CWA DURING LATER
AFTERNOON AND EARLY EVENING HOURS AHEAD OF THE COLD FRONT. VIS
SATELLITE DOES DEPICT SOME ENHANCED CU ACROSS FAR NW IL AHEAD OF THE
FRONT AT THIS TIME. WHILE SPC HAS SHIFTED DAY 1 SEVERE SLIGHT RISK
WELL EAST/SOUTH OF THE CWA...DRIER AIR AND STEEPER LAPSE RATES ALOFT
PER 12Z DVN SOUNDING SUGGESTS THERE COULD BE AN ISOLATED NEAR SEVERE
WIND/HAIL THREAT OVER NORTHERN IL THIS AFTERNOON. FARTHER
SOUTHEAST...12Z SOUNDING FROM ILX INDICATES A DEEPER STABLE LAYER
NEAR THE SURFACE...WITH WARMER TEMPS IN THE 850-700 MB LAYER LIKELY
KEEPING THINGS MORE CAPPED ACROSS OUR SOUTHEAST.
PER ABOVE REASONING...HAVE ELIMINATED MORNING POPS ACROSS THE CWA...
AND LOWERED POPS ACROSS THE SOUTHEAST THIS AFTERNOON. ALSO BUMPED
TEMPS A DEGREE OR TWO IN MOST AREAS.
RATZER
//PREV DISCUSSION...
326 AM...MAIN FORECAST CONCERN REMAINS CONVECTIVE TRENDS AND
HEAVY RAIN POTENTIAL INTO THIS EVENING...MAINLY OVER THE SOUTHEAST
HALF/THIRD OF THE CWA.
UPPER TROUGH FINALLY STARTS TO SHIFT NORTHEAST ACROSS THE UPPER
MIDWEST/LAKES REGION TODAY AND TONIGHT. NEXT SHORTWAVE THAT LIFTS
NORTHEAST LATER TODAY INTO THIS AFTERNOON EXPECTED TO BE A LITTLE
FURTHER EAST AFFECTING AREAS GENERALLY EAST OF THE I-55 CORRIDOR
AND THERE HAS BEEN REASONABLE CONSISTENCY WITH THIS TREND OVER THE
PAST DAY OR SO. THOUGH INSTABILITY FURTHER NORTHWEST STILL
SUFFICIENT TO FOR AT LEAST ISOLATED ACTIVITY THIS AFTERNOON INTO
THIS EVENING. BUT THE THREAT OF ANY SEVERE WEATHER SHOULD BE
PRIMARILY EAST OF I-55 WITH THE MAIN THREAT AGAIN DAMAGING WIND
GUSTS. IN ADDITION...HEAVY RAIN FALLING OVER THE SAME AREAS THAT
RECEIVED HEAVY RAIN FRIDAY NIGHT WILL ONLY INCREASE THE THREAT FOR
FLASH FLOODING...THUS NO CHANGES TO THE CURRENT FLASH FLOOD WATCH.
TIMING THOUGH REMAINS SOMEWHAT UNCERTAIN AS THIS MORNING COULD
END UP BEING FAIRLY DRY/QUIET WITH CONVECTION NOT FIRING UNTIL
EARLY/MID AFTERNOON...THEN QUICKLY SHIFTING EAST.
A WEAK WAVE ROTATES ACROSS THE AREA LATE TONIGHT INTO SUNDAY
MORNING AND SOME SHOWERS ARE POSSIBLE. THEN COOLER AIR SPREADS
ACROSS THE AREA SUNDAY NIGHT INTO MONDAY AS BROAD/WEAK HIGH
PRESSURE BUILDS ACROSS THE REGION. LOWS SUNDAY NIGHT COULD EASILY
DROP WELL INTO THE 40S WITH EXPECTED LIGHT WINDS. COULD BE SOME
CLOUDS AROUND BUT WITH AN EXPECTED LAKE BREEZE SUNDAY AFTERNOON
ALLOWING COOLED LAKE AIR TO FLOW INLAND...THINK COOLER IS BETTER
FOR LOWS BY MONDAY MORNING. AIRMASS WARMS SLIGHTLY ALONG WITH THE
POTENTIAL FOR SOME CLOUDS MONDAY NIGHT INTO TUESDAY MORNING...BUT
LOWS IN THE UPPER 40S LOOK ON TRACK BY TUESDAY MORNING. PREVAILING
EASTERLY FLOW WILL KEEP THE LAKESHORE AREAS COOLER FOR HIGHS
THROUGH MID WEEK BUT WITH EARLY JUNE SUNSHINE...THINK LOWER 70S
WELL INLAND WOULD BE REACHABLE.
CONFIDENCE REGARDING POPS MID/LATE NEXT WEEK IS FAIRLY LOW AS
ANOTHER UPPER LOW MOVES ACROSS THE PLAINS. WHILE SOMEWHAT
PROGRESSIVE...HOW FAR EAST VARIOUS PRECIP WAVES REACH IS DOUBTFUL
FROM THIS DISTANCE. STILL HAVE CHANCE POPS BY TUESDAY NIGHT BUT
FURTHER REFINEMENT WILL BE NEEDED WITH LATER FORECASTS. CMS
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 18Z...
* MVFR CIGS THIS AFTERNOON AND EVENING.
* SCATTERED SHOWERS AND THUNDERSTORMS DEVELOPING MID AFTERNOON AND
ENDING EARLY EVENING.
* STRONG GUSTY SOUTHWEST WINDS THIS AFTERNOON DIMINISHING THIS
EVENING AND SHIFTING WNW OVERNIGHT.
* MVFR AND POSSIBLE IFR CIGS LATE TONIGHT INTO EARLY SUNDAY
MORNING.
ALLSOPP
//DISCUSSION...UPDATED 18Z...
MAIN FORECAST CONCERN IS THE POTENTIAL FOR A SCATTERED TO BROKEN
LINE OF SHOWERS AND THUNDERSTORMS TO DEVELOP OVER NORTHERN
ILLINOIS BY MID AFTERNOON AND SHIFT EAST INTO INDIANA EARLY THIS
EVENING. SCATTERED LIGHT SHOWERS MAY LINGER THROUGH THE EVENING.
WARM AND VERY MOIST LOWER ATMOSPHERE IS STILL IN PLACE ACROSS
NORTHERN IL AND NORTHWEST IN EARLY THIS AFTERNOON. EXTENSIVE CLOUD
COVER HAS LIMITED INSTABILITY OVER THE AREA BUT AS LOW PRESSURE
MOVES FROM WISCONSIN TO NORTHERN MICHIGAN...A COLD FRONT WILL MOVE
ACROSS THE AREA THIS EVENING. SHOWERS AND THUNDERSTORMS ARE
EXPECTED TO DEVELOP ALONG AND AHEAD OF THE FRONT. AFTER THE FRONT
PASSES...SOME LINGERING LIGHT SHOWERS MAY PERSISTS TO AROUND
MIDNIGHT.
WIDESPREAD MVFR CIGS IN THE WARM MOIST AIRMASS AHEAD OF THE FRONT
HAVE BEEN SLOWLY LIFTING THROUGH THE MORNING/EARLY AFTERNOON BUT
REMAIN MOSTLY BETWEEN 2-3 THOUSAND FEET. EXPECT THE MVFR CIGS TO
REMAIN THROUGH THE REST OF THE AFTERNOON AND EVENING. STRONG GUSTY
SOUTHWEST WINDS WILL DIMINISH THIS EVENING. THE INITIAL PRESSURE
TROF/FRONT WILL SHIFT WINDS TO WSW THIS EVENING. THE PUSH OF
COLDER AIR WILL COME WITH A SECONDARY FRONT LATE TONIGHT. THIS
WILL TURN WINDS WNW. GUIDANCE SUGGESTS SOME IFR OR EVEN LOW IFR
CIGS TO DEVELOP LATE TONIGHT OR TOWARD MORNING. LIFR WOULD BE RARE
FOR JUNE BUT HAVE ADDED A TEMPO IFR CIG GROUP TO THE TAFS. CIGS
SHOULD LIFT SUNDAY MORNING AS STRONG NORTHWEST WINDS BEGIN MIXING
IN COOLER DRIER AIR.
A LAKE BREEZE MAY DEVELOP BY MID OR LATE AFTERNOON SUNDAY AND WILL
LIKELY REFLECT THIS IN LATER TAF ISSUANCES.
ALLSOPP
//ORD AND MDW CONFIDENCE...UPDATED 18Z...
* MEDIUM CONFIDENCE IN CIG TRENDS THIS AFTERNOON AND EVENING.
* MEDIUM-HIGH CONFIDENCE IN WIND FORECAST.
* MEDIUM-HIGH CONFIDENCE IN SHOWERS AND THUNDERSTORMS DEVELOPING
MID AFTERNOON AND ENDING EARLY EVENING. LOW CONFIDENCE IN
THUNDER AT AIRPORTS.
* MEDIUM-HIGH CONFIDENCE IN MVFR CIGS LATE TONIGHT INTO EARLY
SUNDAY MORNING. LOW CONFIDENCE IN IFR CIG DEVELOPING.
ALLSOPP
//OUTLOOK FOR ORD/MDW FOR 00Z MONDAY-12Z SATURDAY...UPDATED 12Z...
SUNDAY NIGHT-TUESDAY...MAINLY VFR.
WEDNESDAY-FRIDAY...CHC OF TSRA.
MTF
&&
.MARINE...
218 PM CDT
MODERATE SOUTHERLY WINDS ARE OCCURRING AHEAD OF AN AREA OF LOW
PRESSURE AND ITS ATTENDANT COLD FRONT WHICH ARE EXPECTED TO PASS
OVER THE LAKE TONIGHT. A BRIEF LULL IN THE WINDS MAY OCCUR WITH THE
FRONTAL TROUGH THIS EVENING...BUT THEN WINDS ARE EXPECTED TO
SHIFT TO NORTHWESTERLY AND RAMP BACK UP INTO THE 20 TO 25 KT RANGE
FOR MUCH OF THE LAKE OVERNIGHT. WINDS SHOULD COME DOWN THROUGH
THE DAY SUNDAY...REMAINING RELATIVELY LIGHT ON MONDAY WITH LAKE
BREEZES DEVELOPING. ANOTHER AREA OF LOW PRESSURE BEGINS TO TAKE
SHAPE OVER THE PLAINS LATE MONDAY INTO TUESDAY WITH SOUTHEASTERLY
WINDS FRESHENING UP TO PERHAPS 15 TO 20 KT AT TIMES THROUGH
THURSDAY. THURSDAY NIGHT...THE LOW WEAKENS AS IT PASSES SOUTH OF
THE LAKE WITH WINDS TURNING NORTHERLY FRIDAY THROUGH THE WEEKEND.
BMD
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...FLASH FLOOD WATCH...ILZ032-ILZ033-ILZ039 UNTIL 7 PM SATURDAY.
IN...FLASH FLOOD WATCH...INZ010-INZ011-INZ019 UNTIL 7 PM SATURDAY.
LM...DENSE FOG ADVISORY...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565
UNTIL 9 PM SATURDAY.
SMALL CRAFT ADVISORY...NEARSHORE WATERS
UNTIL 4 PM 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
1244 PM CDT SAT JUN 1 2013
.DISCUSSION...
1141 AM CDT
FOR MORNING UPDATE...
HAVE MADE SOME CHANGES TO POP COVERAGE/TIMING THROUGH THIS
AFTERNOON...AND HAVE TRIMMED THE NORTHERN TIER OF COUNTIES FROM THE
FLASH FLOOD WATCH.
SFC LOW PRESSURE WAS OVER THE UPPER MISSISSIPPI VALLEY THIS
MORNING...ASSOCIATED WITH UPPER TROUGH/LOW OVER MINNESOTA. SURFACE
COLD FRONT EXTENDS SOUTH FROM THE LOW ALONG THE MISSISSIPPI RIVER
AND THEN SOUTHWEST ACROSS CENTRAL MO. WHILE FORECAST AREA REMAINS IN
WARM/MOIST SOUTH FLOW AHEAD OF THE COLD FRONT...COMBINED OUTFLOW
FROM SERIES OF THUNDERSTORM COMPLEXES HAS PUSHED SOUTH OF THE OHIO
RIVER WITH MOSTLY CLOUDY/SLIGHTLY DRIER LOW LEVEL AIR IN PLACE
ACROSS NORTHERN IL/NORTHWEST INDIANA. THIS WILL VERY LIKELY SHIFT
THE FOCUS OF GREATER HEAVY RAIN/SEVERE THREAT SOUTH OF THE CWA FOR
THE REMAINDER OF THE AFTERNOON/EVENING. ACCORDINGLY...HAVE CANCELLED
PORTION OF FLASH FLOOD WATCH...KEEPING ONLY SOUTH TIER WHERE 2-3
INCH RAINS OCCURRED YESTERDAY AFTERNOON/EVENING. THIS AREA ALSO MORE
FAVORED FOR THE OF POTENTIAL LOCALIZED HEAVIER RAINFALL LATE THIS
AFTERNOON/EARLY EVENING...WITH HIGHER PWATS/STRONGER 850 MB MOIST
TRANSPORT AND SLOWER EXPECTED STORM PROPAGATION ACROSS THE
SOUTHEASTERN CWA.
WHILE OVERALL THREAT/COVERAGE OF TSRA APPEARS TO BE
DIMINISHED...MORNING RAOB ANALYSIS AND WATER VAPOR IMAGERY DOES
DEPICT A SHORT WAVE TROUGH ACROSS NORTHERN MISSOURI WHICH WILL LIFT
NORTHEAST INTO NORTHERN IL THIS AFTERNOON. 12Z SOUNDING FROM DVN
INDICATES INVERSION WAS FAIRLY SHALLOW ACROSS THE WEST/NORTHWEST
PARTS OF THE FA...WHICH COMBINED WITH LOW LEVEL CONVERGENCE AHEAD OF
THE COLD FRONT AND LARGER SCALE ASCENT WITH APPROACHING SHORT WAVE
IS EXPECTED TO YIELD AROUND 800 J/KG MLCAPE WITH LITTLE/NO CIN BY
MID AFTERNOON HOURS. MORNING RUNS OF THE HRRR SUGGEST
ISOLATED/SCATTERED SHRA/TSRA DEVELOPMENT OVER WESTERN/NORTHWESTERN
IL WHICH WOULD THEN SHIFT EAST-NORTHEAST ACROSS THE CWA DURING LATER
AFTERNOON AND EARLY EVENING HOURS AHEAD OF THE COLD FRONT. VIS
SATELLITE DOES DEPICT SOME ENHANCED CU ACROSS FAR NW IL AHEAD OF THE
FRONT AT THIS TIME. WHILE SPC HAS SHIFTED DAY 1 SEVERE SLIGHT RISK
WELL EAST/SOUTH OF THE CWA...DRIER AIR AND STEEPER LAPSE RATES ALOFT
PER 12Z DVN SOUNDING SUGGESTS THERE COULD BE AN ISOLATED NEAR SEVERE
WIND/HAIL THREAT OVER NORTHERN IL THIS AFTERNOON. FARTHER
SOUTHEAST...12Z SOUNDING FROM ILX INDICATES A DEEPER STABLE LAYER
NEAR THE SURFACE...WITH WARMER TEMPS IN THE 850-700 MB LAYER LIKELY
KEEPING THINGS MORE CAPPED ACROSS OUR SOUTHEAST.
PER ABOVE REASONING...HAVE ELIMINATED MORNING POPS ACROSS THE CWA...
AND LOWERED POPS ACROSS THE SOUTHEAST THIS AFTERNOON. ALSO BUMPED
TEMPS A DEGREE OR TWO IN MOST AREAS.
RATZER
//PREV DISCUSSION...
326 AM...MAIN FORECAST CONCERN REMAINS CONVECTIVE TRENDS AND
HEAVY RAIN POTENTIAL INTO THIS EVENING...MAINLY OVER THE SOUTHEAST
HALF/THIRD OF THE CWA.
UPPER TROUGH FINALLY STARTS TO SHIFT NORTHEAST ACROSS THE UPPER
MIDWEST/LAKES REGION TODAY AND TONIGHT. NEXT SHORTWAVE THAT LIFTS
NORTHEAST LATER TODAY INTO THIS AFTERNOON EXPECTED TO BE A LITTLE
FURTHER EAST AFFECTING AREAS GENERALLY EAST OF THE I-55 CORRIDOR
AND THERE HAS BEEN REASONABLE CONSISTENCY WITH THIS TREND OVER THE
PAST DAY OR SO. THOUGH INSTABILITY FURTHER NORTHWEST STILL
SUFFICIENT TO FOR AT LEAST ISOLATED ACTIVITY THIS AFTERNOON INTO
THIS EVENING. BUT THE THREAT OF ANY SEVERE WEATHER SHOULD BE
PRIMARILY EAST OF I-55 WITH THE MAIN THREAT AGAIN DAMAGING WIND
GUSTS. IN ADDITION...HEAVY RAIN FALLING OVER THE SAME AREAS THAT
RECEIVED HEAVY RAIN FRIDAY NIGHT WILL ONLY INCREASE THE THREAT FOR
FLASH FLOODING...THUS NO CHANGES TO THE CURRENT FLASH FLOOD WATCH.
TIMING THOUGH REMAINS SOMEWHAT UNCERTAIN AS THIS MORNING COULD
END UP BEING FAIRLY DRY/QUIET WITH CONVECTION NOT FIRING UNTIL
EARLY/MID AFTERNOON...THEN QUICKLY SHIFTING EAST.
A WEAK WAVE ROTATES ACROSS THE AREA LATE TONIGHT INTO SUNDAY
MORNING AND SOME SHOWERS ARE POSSIBLE. THEN COOLER AIR SPREADS
ACROSS THE AREA SUNDAY NIGHT INTO MONDAY AS BROAD/WEAK HIGH
PRESSURE BUILDS ACROSS THE REGION. LOWS SUNDAY NIGHT COULD EASILY
DROP WELL INTO THE 40S WITH EXPECTED LIGHT WINDS. COULD BE SOME
CLOUDS AROUND BUT WITH AN EXPECTED LAKE BREEZE SUNDAY AFTERNOON
ALLOWING COOLED LAKE AIR TO FLOW INLAND...THINK COOLER IS BETTER
FOR LOWS BY MONDAY MORNING. AIRMASS WARMS SLIGHTLY ALONG WITH THE
POTENTIAL FOR SOME CLOUDS MONDAY NIGHT INTO TUESDAY MORNING...BUT
LOWS IN THE UPPER 40S LOOK ON TRACK BY TUESDAY MORNING. PREVAILING
EASTERLY FLOW WILL KEEP THE LAKESHORE AREAS COOLER FOR HIGHS
THROUGH MID WEEK BUT WITH EARLY JUNE SUNSHINE...THINK LOWER 70S
WELL INLAND WOULD BE REACHABLE.
CONFIDENCE REGARDING POPS MID/LATE NEXT WEEK IS FAIRLY LOW AS
ANOTHER UPPER LOW MOVES ACROSS THE PLAINS. WHILE SOMEWHAT
PROGRESSIVE...HOW FAR EAST VARIOUS PRECIP WAVES REACH IS DOUBTFUL
FROM THIS DISTANCE. STILL HAVE CHANCE POPS BY TUESDAY NIGHT BUT
FURTHER REFINEMENT WILL BE NEEDED WITH LATER FORECASTS. CMS
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 18Z...
* MVFR CIGS THIS AFTERNOON AND EVENING.
* SCATTERED SHOWERS AND THUNDERSTORMS DEVELOPING MID AFTERNOON AND
ENDING EARLY EVENING.
* STRONG GUSTY SOUTHWEST WINDS THIS AFTERNOON DIMINISHING THIS
EVENING AND SHIFTING WNW OVERNIGHT.
* MVFR AND POSSIBLE IFR CIGS LATE TONIGHT INTO EARLY SUNDAY
MORNING.
ALLSOPP
//DISCUSSION...UPDATED 18Z...
MAIN FORECAST CONCERN IS THE POTENTIAL FOR A SCATTERED TO BROKEN
LINE OF SHOWERS AND THUNDERSTORMS TO DEVELOP OVER NORTHERN
ILLINOIS BY MID AFTERNOON AND SHIFT EAST INTO INDIANA EARLY THIS
EVENING. SCATTERED LIGHT SHOWERS MAY LINGER THROUGH THE EVENING.
WARM AND VERY MOIST LOWER ATMOSPHERE IS STILL IN PLACE ACROSS
NORTHERN IL AND NORTHWEST IN EARLY THIS AFTERNOON. EXTENSIVE CLOUD
COVER HAS LIMITED INSTABILITY OVER THE AREA BUT AS LOW PRESSURE
MOVES FROM WISCONSIN TO NORTHERN MICHIGAN...A COLD FRONT WILL MOVE
ACROSS THE AREA THIS EVENING. SHOWERS AND THUNDERSTORMS ARE
EXPECTED TO DEVELOP ALONG AND AHEAD OF THE FRONT. AFTER THE FRONT
PASSES...SOME LINGERING LIGHT SHOWERS MAY PERSISTS TO AROUND
MIDNIGHT.
WIDESPREAD MVFR CIGS IN THE WARM MOIST AIRMASS AHEAD OF THE FRONT
HAVE BEEN SLOWLY LIFTING THROUGH THE MORNING/EARLY AFTERNOON BUT
REMAIN MOSTLY BETWEEN 2-3 THOUSAND FEET. EXPECT THE MVFR CIGS TO
REMAIN THROUGH THE REST OF THE AFTERNOON AND EVENING. STRONG GUSTY
SOUTHWEST WINDS WILL DIMINISH THIS EVENING. THE INITIAL PRESSURE
TROF/FRONT WILL SHIFT WINDS TO WSW THIS EVENING. THE PUSH OF
COLDER AIR WILL COME WITH A SECONDARY FRONT LATE TONIGHT. THIS
WILL TURN WINDS WNW. GUIDANCE SUGGESTS SOME IFR OR EVEN LOW IFR
CIGS TO DEVELOP LATE TONIGHT OR TOWARD MORNING. LIFR WOULD BE RARE
FOR JUNE BUT HAVE ADDED A TEMPO IFR CIG GROUP TO THE TAFS. CIGS
SHOULD LIFT SUNDAY MORNING AS STRONG NORTHWEST WINDS BEGIN MIXING
IN COOLER DRIER AIR.
A LAKE BREEZE MAY DEVELOP BY MID OR LATE AFTERNOON SUNDAY AND WILL
LIKELY REFLECT THIS IN LATER TAF ISSUANCES.
ALLSOPP
//ORD AND MDW CONFIDENCE...UPDATED 18Z...
* MEDIUM CONFIDENCE IN CIG TRENDS THIS AFTERNOON AND EVENING.
* MEDIUM-HIGH CONFIDENCE IN WIND FORECAST.
* MEDIUM-HIGH CONFIDENCE IN SHOWERS AND THUNDERSTORMS DEVELOPING
MID AFTERNOON AND ENDING EARLY EVENING. LOW CONFIDENCE IN
THUNDER AT AIRPORTS.
* MEDIUM-HIGH CONFIDENCE IN MVFR CIGS LATE TONIGHT INTO EARLY
SUNDAY MORNING. LOW CONFIDENCE IN IFR CIG DEVELOPING.
ALLSOPP
//OUTLOOK FOR ORD/MDW FOR 00Z MONDAY-12Z SATURDAY...UPDATED 12Z...
SUNDAY NIGHT-TUESDAY...MAINLY VFR.
WEDNESDAY-FRIDAY...CHC OF TSRA.
MTF
&&
.MARINE...
210 AM CDT
LOW PRESSURE WILL MAINTAIN ITS INTENSITY TODAY AS IT SHIFTS ACROSS
WI AND TO THE CENTRAL GREAT LAKES BY THIS EVE. INITIALLY IN THE
SOUTHERLY FLOW AHEAD OF THE LAKE...MOIST AIR OVER THE COOLER LAKE
HAS LED TO FOG. WHILE IT CANNOT BE DETERMINED HOW WIDESPREAD THIS
IS...THERE HAVE BEEN MULTIPLE SHIPS OBS SINCE FRIDAY NIGHT TO HAVE
REPORTED DENSE FOG...ALONG WITH A COUPLE NEARBY SHORE LOCATIONS IN
MI. A COLD FRONT EXTENDING FROM THE LOW WILL MOVE ACROSS THE LAKE
LATE TONIGHT TURNING THE WINDS NORTHWESTERLY AND PROVIDING AN
INCREASE IN SPEED WITH COLD AIR ADVECTION INTO SUNDAY. HIGH PRESSURE
WILL THEN BRING TRANQUIL CONDITIONS ACROSS THE LAKE MON AND TUE
BEFORE A WEAK TROUGH PASSAGE...WHICH WILL THEN AGAIN BE FOLLOWED BY
RIDGING.
MTF
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...FLASH FLOOD WATCH...ILZ032-ILZ033-ILZ039 UNTIL 7 PM SATURDAY.
IN...FLASH FLOOD WATCH...INZ010-INZ011-INZ019 UNTIL 7 PM SATURDAY.
LM...DENSE FOG ADVISORY...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ868-LMZ870-
LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 9 PM SATURDAY.
&&
$$
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AREA FORECAST DISCUSSION
NWS LINCOLN IL
1240 PM CDT SAT JUN 1 2013
.DISCUSSION...
ISSUED 1040 AM CDT SAT JUN 1 2013
15Z/10AM SURFACE CHART SHOWS LOW PRESSURE OVER WESTERN
WISCONSIN...WITH TRAILING COLD FRONT EXTENDING ACROSS EASTERN IOWA
INTO NORTH-CENTRAL MISSOURI. NOT MUCH HAPPENING IMMEDIATELY
ALONG/AHEAD OF THE FRONT YET...HOWEVER STILL HAVE PLENTY OF
ONGOING RAIN FURTHER SOUTH IN THE OHIO RIVER VALLEY ASSOCIATED
WITH LAST NIGHTS STORM COMPLEX. LIGHT RAIN CONTINUES TO FALL
ACROSS THE S/SE KILX CWA...MAINLY ALONG AND SOUTH OF A PARIS TO
EFFINGHAM LINE. 12Z NAM AND HRRR TRY TO PUSH A WAVE OF THIS PRECIP
FURTHER NORTH INTO THE DECATUR AND CHAMPAIGN AREAS...HOWEVER SEE NO
EVIDENCE OF THIS HAPPENING ON RADAR/SATELLITE LOOPS. WILL
THEREFORE FOCUS LIKELY POPS ACROSS THE S/SE CWA...WITH ONLY LOW
CHANCE FURTHER NORTH ACROSS MUCH OF CENTRAL ILLINOIS THROUGH THE
EARLY AFTERNOON. AFTER THAT...MODELS INDICATE SCATTERED CONVECTION
FIRING ALONG THE COLD FRONT BY MID TO LATE AFTERNOON...MAINLY
ALONG AND WEST OF I-55. WILL GO WITH CHANCE POPS ACROSS THE BOARD
IN THE AFTERNOON...WITH BEST CHANCES ACROSS THE WESTERN HALF OF
THE CWA. FRONT WILL PROGRESS EASTWARD...TAKING BEST RAIN CHANCES
INTO EAST-CENTRAL ILLINOIS THIS EVENING...THEN COMPLETELY OUT OF
THE AREA OVERNIGHT. ZONE UPDATE WILL BE ISSUED SHORTLY.
&&
.AVIATION...
ISSUED 1240 PM CDT SAT JUN 1 2013
MVFR CEILINGS WILL PERSIST AT THE CENTRAL ILLINOIS TERMINALS FOR
THE NEXT COUPLE OF HOURS BEFORE GRADUALLY IMPROVING TO VFR BY MID
TO LATE AFTERNOON. COLD FRONT CURRENTLY ACROSS CENTRAL IOWA WILL
PUSH EASTWARD...TRIGGERING WIDELY SCATTERED SHOWERS/THUNDER. HRRR
CONTINUES TO SUGGEST CONVECTIVE DEVELOPMENT MAINLY BETWEEN 18Z AND
00Z...WITH PERHAPS A FEW LINGERING CELLS ACROSS THE EAST THROUGH
02Z. DUE TO EXPECTED LIMITED AREAL COVERAGE...WILL ONLY MENTION
VCTS AT THIS TIME. ONCE THE FRONT PASSES...SOUTHERLY WINDS WILL
BECOME WESTERLY THIS EVENING...THEN NORTHWESTERLY BY SUNDAY
MORNING. MVFR CEILINGS WRAPPING AROUND SURFACE LOW PRESSURE
CENTERED OVER WISCONSIN WILL ADVECT INTO THE REGION FROM WEST TO
EAST TONIGHT. BASED ON NAM FORECAST SOUNDINGS...1500FT CEILINGS
WILL RETURN TO KPIA BY 04Z...THEN FURTHER EAST TO KCMI BY AROUND
06Z.
BARNES
&&
.PREV DISCUSSION...
ISSUED 311 AM CDT SAT JUN 1 2013
MCS AND ASSOCIATED SEVERE WEATHER CONTINUES IN A WIDE SWATH FROM
SOUTHERN INDIANA TO OKLAHOMA EARLY THIS MORNING. WORST OF THE
STORMS HAVE EXITED THE CWA...ALTHOUGH SOME WIDESPREAD LIGHT TO
MODERATE RAIN CONTINUES EAST OF I-55 AS OF 245 AM.
MAIN CONCERN FOR THIS FORECAST PACKAGE IS OVER THE NEXT 18
HOURS... WITH SEVERE WEATHER AND FLOODING POTENTIAL CONTINUING.
SHORT TERM...TODAY THROUGH MONDAY...
EMPHASIS ON FLOOD POTENTIAL WILL MAINLY BE ACROSS THE SOUTHEAST
HALF OF THE CWA TODAY...AS AXIS OF HIGH PRECIPITABLE WATER VALUES
OF 1.75 TO 2 INCHES SHIFTS EASTWARD AHEAD OF THE DRY SLOT THAT
WILL ARRIVE THIS EVENING. HAVE DROPPED THE FLASH FLOOD WATCH FOR
AREAS WEST OF I-55 AS ADDITIONAL RAINFALL IN THIS AREA SHOULD BE
LESS THAN A QUARTER INCH. ANOTHER HALF TO 1 INCH POSSIBLE ACROSS
AREAS SOUTH OF I-70...WHICH HAVE BEEN HAMMERED WITH 2 TO 5 INCHES
OVER THE LAST COUPLE DAYS...AS FORECAST SOUNDINGS SHOW WARM CLOUD
DEPTH OF 11KFT IN THAT AREA. A RENEWED SURGE OF SHOWERS/STORMS
EXPECTED TO DEVELOP LATER THIS MORNING AND BE WIDESPREAD THIS
AFTERNOON. LATEST SPC SEVERE WEATHER OUTLOOK FOCUSES ON THE AREA
EAST OF HIGHWAY 51 FOR RENEWED SEVERE DEVELOPMENT. PRECIPITATION
SHOULD QUICKLY SHUT OFF EARLY THIS EVENING AS DRY SLOT PUNCHES IN
WITH THE SURFACE LOW PASSING TO OUR NORTH.
AFTER THAT...A COOLER AND MUCH QUIETER PERIOD IS ON TAP FOR A FEW
DAYS...AS A STRONG UPPER LOW SWINGS THROUGH THE NORTHERN GREAT
LAKES REGION. MAY SEE A FEW LIGHT SHOWERS SWING THROUGH ON
SUNDAY...MAINLY IN THE EASTERN CWA...AS A TROUGH QUICKLY MOVES
THROUGH THE AREA. HIGHS AROUND 70 WILL BE FAIRLY COMMON FOR SUNDAY
AND MONDAY.
LONG TERM...TUESDAY THROUGH FRIDAY...
MAIN CONCERN IN THIS TIME FRAME IS WITH TIMING OF SHOWERS/STORMS
DURING THE MIDDLE OF THE WEEK. MEDIUM RANGE MODELS IN REASONABLE
AGREEMENT WITH A CLOSED LOW TRACKING ACROSS MONTANA AND NORTH
DAKOTA THROUGH MIDWEEK. LATEST ECMWF AND CANADIAN MODELS HANG UP
THE UPPER LOW OVER THE MINNESOTA ARROWHEAD REGION...WHILE THE GFS
IS A BIT MORE PROGRESSIVE. WILL SLOWLY INCREASE RAIN CHANCES IN
THE GRIDS FROM WEST TO EAST...WITH MENTIONABLE POPS HOLDING OFF IN
THE SOUTHEAST CWA UNTIL THURSDAY. UPPER TROUGH SHOULD THEN TRACK
THROUGH ON FRIDAY...WITH SURFACE RIDGING BUILDING SOUTHWEST FROM
THE GREAT LAKES. AT THIS POINT...THINK THE CHANCES OF RAIN ON
FRIDAY ARE LOW...BUT WILL MAINTAIN SOME LOW POPS EAST OF I-55
CLOSER TO THE CENTER OF THE TROUGH.
GEELHART
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH UNTIL 7 PM CDT THIS EVENING FOR ILZ038-042>046-
051>057-061>063-066>068-071>073.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1142 AM CDT SAT JUN 1 2013
.DISCUSSION...
1141 AM CDT
FOR MORNING UPDATE...
HAVE MADE SOME CHANGES TO POP COVERAGE/TIMING THROUGH THIS
AFTERNOON...AND HAVE TRIMMED THE NORTHERN TIER OF COUNTIES FROM THE
FLASH FLOOD WATCH.
SFC LOW PRESSURE WAS OVER THE UPPER MISSISSIPPI VALLEY THIS
MORNING...ASSOCIATED WITH UPPER TROUGH/LOW OVER MINNESOTA. SURFACE
COLD FRONT EXTENDS SOUTH FROM THE LOW ALONG THE MISSISSIPPI RIVER
AND THEN SOUTHWEST ACROSS CENTRAL MO. WHILE FORECAST AREA REMAINS IN
WARM/MOIST SOUTH FLOW AHEAD OF THE COLD FRONT...COMBINED OUTFLOW
FROM SERIES OF THUNDERSTORM COMPLEXES HAS PUSHED SOUTH OF THE OHIO
RIVER WITH MOSTLY CLOUDY/SLIGHTLY DRIER LOW LEVEL AIR IN PLACE
ACROSS NORTHERN IL/NORTHWEST INDIANA. THIS WILL VERY LIKELY SHIFT
THE FOCUS OF GREATER HEAVY RAIN/SEVERE THREAT SOUTH OF THE CWA FOR
THE REMAINDER OF THE AFTERNOON/EVENING. ACCORDINGLY...HAVE CANCELLED
PORTION OF FLASH FLOOD WATCH...KEEPING ONLY SOUTH TIER WHERE 2-3
INCH RAINS OCCURRED YESTERDAY AFTERNOON/EVENING. THIS AREA ALSO MORE
FAVORED FOR THE OF POTENTIAL LOCALIZED HEAVIER RAINFALL LATE THIS
AFTERNOON/EARLY EVENING...WITH HIGHER PWATS/STRONGER 850 MB MOIST
TRANSPORT AND SLOWER EXPECTED STORM PROPAGATION ACROSS THE
SOUTHEASTERN CWA.
WHILE OVERALL THREAT/COVERAGE OF TSRA APPEARS TO BE
DIMINISHED...MORNING RAOB ANALYSIS AND WATER VAPOR IMAGERY DOES
DEPICT A SHORT WAVE TROUGH ACROSS NORTHERN MISSOURI WHICH WILL LIFT
NORTHEAST INTO NORTHERN IL THIS AFTERNOON. 12Z SOUNDING FROM DVN
INDICATES INVERSION WAS FAIRLY SHALLOW ACROSS THE WEST/NORTHWEST
PARTS OF THE FA...WHICH COMBINED WITH LOW LEVEL CONVERGENCE AHEAD OF
THE COLD FRONT AND LARGER SCALE ASCENT WITH APPROACHING SHORT WAVE
IS EXPECTED TO YIELD AROUND 800 J/KG MLCAPE WITH LITTLE/NO CIN BY
MID AFTERNOON HOURS. MORNING RUNS OF THE HRRR SUGGEST
ISOLATED/SCATTERED SHRA/TSRA DEVELOPMENT OVER WESTERN/NORTHWESTERN
IL WHICH WOULD THEN SHIFT EAST-NORTHEAST ACROSS THE CWA DURING LATER
AFTERNOON AND EARLY EVENING HOURS AHEAD OF THE COLD FRONT. VIS
SATELLITE DOES DEPICT SOME ENHANCED CU ACROSS FAR NW IL AHEAD OF THE
FRONT AT THIS TIME. WHILE SPC HAS SHIFTED DAY 1 SEVERE SLIGHT RISK
WELL EAST/SOUTH OF THE CWA...DRIER AIR AND STEEPER LAPSE RATES ALOFT
PER 12Z DVN SOUNDING SUGGESTS THERE COULD BE AN ISOLATED NEAR SEVERE
WIND/HAIL THREAT OVER NORTHERN IL THIS AFTERNOON. FARTHER
SOUTHEAST...12Z SOUNDING FROM ILX INDICATES A DEEPER STABLE LAYER
NEAR THE SURFACE...WITH WARMER TEMPS IN THE 850-700 MB LAYER LIKELY
KEEPING THINGS MORE CAPPED ACROSS OUR SOUTHEAST.
PER ABOVE REASONING...HAVE ELIMINATED MORNING POPS ACROSS THE CWA...
AND LOWERED POPS ACROSS THE SOUTHEAST THIS AFTERNOON. ALSO BUMPED
TEMPS A DEGREE OR TWO IN MOST AREAS.
RATZER
&&
.PREV DISCUSSION...
326 AM...MAIN FORECAST CONCERN REMAINS CONVECTIVE TRENDS AND
HEAVY RAIN POTENTIAL INTO THIS EVENING...MAINLY OVER THE SOUTHEAST
HALF/THIRD OF THE CWA.
UPPER TROUGH FINALLY STARTS TO SHIFT NORTHEAST ACROSS THE UPPER
MIDWEST/LAKES REGION TODAY AND TONIGHT. NEXT SHORTWAVE THAT LIFTS
NORTHEAST LATER TODAY INTO THIS AFTERNOON EXPECTED TO BE A LITTLE
FURTHER EAST AFFECTING AREAS GENERALLY EAST OF THE I-55 CORRIDOR
AND THERE HAS BEEN REASONABLE CONSISTENCY WITH THIS TREND OVER THE
PAST DAY OR SO. THOUGH INSTABILITY FURTHER NORTHWEST STILL
SUFFICIENT TO FOR AT LEAST ISOLATED ACTIVITY THIS AFTERNOON INTO
THIS EVENING. BUT THE THREAT OF ANY SEVERE WEATHER SHOULD BE
PRIMARILY EAST OF I-55 WITH THE MAIN THREAT AGAIN DAMAGING WIND
GUSTS. IN ADDITION...HEAVY RAIN FALLING OVER THE SAME AREAS THAT
RECEIVED HEAVY RAIN FRIDAY NIGHT WILL ONLY INCREASE THE THREAT FOR
FLASH FLOODING...THUS NO CHANGES TO THE CURRENT FLASH FLOOD WATCH.
TIMING THOUGH REMAINS SOMEWHAT UNCERTAIN AS THIS MORNING COULD
END UP BEING FAIRLY DRY/QUIET WITH CONVECTION NOT FIRING UNTIL
EARLY/MID AFTERNOON...THEN QUICKLY SHIFTING EAST.
A WEAK WAVE ROTATES ACROSS THE AREA LATE TONIGHT INTO SUNDAY
MORNING AND SOME SHOWERS ARE POSSIBLE. THEN COOLER AIR SPREADS
ACROSS THE AREA SUNDAY NIGHT INTO MONDAY AS BROAD/WEAK HIGH
PRESSURE BUILDS ACROSS THE REGION. LOWS SUNDAY NIGHT COULD EASILY
DROP WELL INTO THE 40S WITH EXPECTED LIGHT WINDS. COULD BE SOME
CLOUDS AROUND BUT WITH AN EXPECTED LAKE BREEZE SUNDAY AFTERNOON
ALLOWING COOLED LAKE AIR TO FLOW INLAND...THINK COOLER IS BETTER
FOR LOWS BY MONDAY MORNING. AIRMASS WARMS SLIGHTLY ALONG WITH THE
POTENTIAL FOR SOME CLOUDS MONDAY NIGHT INTO TUESDAY MORNING...BUT
LOWS IN THE UPPER 40S LOOK ON TRACK BY TUESDAY MORNING. PREVAILING
EASTERLY FLOW WILL KEEP THE LAKESHORE AREAS COOLER FOR HIGHS
THROUGH MID WEEK BUT WITH EARLY JUNE SUNSHINE...THINK LOWER 70S
WELL INLAND WOULD BE REACHABLE.
CONFIDENCE REGARDING POPS MID/LATE NEXT WEEK IS FAIRLY LOW AS
ANOTHER UPPER LOW MOVES ACROSS THE PLAINS. WHILE SOMEWHAT
PROGRESSIVE...HOW FAR EAST VARIOUS PRECIP WAVES REACH IS DOUBTFUL
FROM THIS DISTANCE. STILL HAVE CHANCE POPS BY TUESDAY NIGHT BUT
FURTHER REFINEMENT WILL BE NEEDED WITH LATER FORECASTS. CMS
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 16Z...
* MVFR CIGS
* STRONG GUSTY SOUTHWEST WINDS
* SCATTERED SHOWERS AND THUNDERSTORMS MID AFTERNOON THROUGH EARLY
EVENING.
* FROPA TONIGHT WITH WINDS SHIFTING TO WNW AND CIGS LOWERING TO
AROUND 15 HND FT.
ALLSOPP
//DISCUSSION...UPDATED 16Z...
WIDESPREAD MVFR CIGS GRADUALLY LIFTING TO 2500-3000 FT BUT WILL
LIKELY REMAIN FAIRLY SOLID THROUGH AFTERNOON. EXPECT SCATTERED
SHOWERS AND THUNDERSTORMS TO DEVELOP AFTER 21Z.
PREVIOUS DISCUSSION...UPDATED 12Z...
LOW PRESSURE WILL MOVE EAST OVER WI TODAY AND TO THE CENTRAL GREAT
LAKES TONIGHT. AS A COLD FRONT FROM THIS FEATURE EASES
EASTWARD...CONVERGENCE OF A CONTINUED UNSTABLE AIR MASS WILL
INCREASE AND LIKELY FOSTER THE DEVELOPMENT OF SCATTERED SHRA/TSRA
BY AFTERNOON. COVERAGE ON THIS IS UNCERTAIN...BUT UNLIKE THE PAST
SEVERAL DAYS...THE POTENTIAL FOR AN ORGANIZED THUNDERSTORM WIND
COMPLEX IS LOW. SOME SHOWERS MAY LINGER BEHIND THE FRONT LATE THIS
EVE INTO OVERNIGHT.
PATCHY MVFR CIGS THIS MORNING NEAR THE WI/IL STATE LINE MAY CLIP
SOME OF THE AIRFIELDS PRIOR TO 14Z. REDEVELOPMENT OF LOW CLOUDS OR
MVFR VISIBILITY CONDITIONS ARE POSSIBLE TONIGHT NEAR THE
FRONT...AND ESPECIALLY SOME CLOUDS IMMEDIATELY BEHIND THE
BOUNDARY. THESE COULD LINGER INTO SUNDAY MORNING.
//ORD AND MDW CONFIDENCE...UPDATED 16Z...
* LOW-MEDIUM CONFIDENCE IN MVFR CIG TRENDS THIS AFTERNOON.
* MEDIUM-HIGH CONFIDENCE IN WIND FORECAST.
* MEDIUM CONFIDENCE IN SCATTERED SHOWERS AND THUNDERSTORMS
DEVELOPING THIS AFTERNOON. LOW CONFIDENCE IN THUNDERSTORMS AT
AIRPORTS.
* MEDIUM CONFIDENCE IN MVFR CIG TRENDS OVERNIGHT.
ALLSOPP
//OUTLOOK FOR ORD/MDW FOR 00Z MONDAY-12Z SATURDAY...UPDATED 12Z...
SUNDAY NIGHT-TUESDAY...MAINLY VFR.
WEDNESDAY-FRIDAY...CHC OF TSRA.
MTF
&&
.MARINE...
210 AM CDT
LOW PRESSURE WILL MAINTAIN ITS INTENSITY TODAY AS IT SHIFTS ACROSS
WI AND TO THE CENTRAL GREAT LAKES BY THIS EVE. INITIALLY IN THE
SOUTHERLY FLOW AHEAD OF THE LAKE...MOIST AIR OVER THE COOLER LAKE
HAS LED TO FOG. WHILE IT CANNOT BE DETERMINED HOW WIDESPREAD THIS
IS...THERE HAVE BEEN MULTIPLE SHIPS OBS SINCE FRIDAY NIGHT TO HAVE
REPORTED DENSE FOG...ALONG WITH A COUPLE NEARBY SHORE LOCATIONS IN
MI. A COLD FRONT EXTENDING FROM THE LOW WILL MOVE ACROSS THE LAKE
LATE TONIGHT TURNING THE WINDS NORTHWESTERLY AND PROVIDING AN
INCREASE IN SPEED WITH COLD AIR ADVECTION INTO SUNDAY. HIGH PRESSURE
WILL THEN BRING TRANQUIL CONDITIONS ACROSS THE LAKE MON AND TUE
BEFORE A WEAK TROUGH PASSAGE...WHICH WILL THEN AGAIN BE FOLLOWED BY
RIDGING.
MTF
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...FLASH FLOOD WATCH...ILZ032-ILZ033-ILZ039 UNTIL 7 PM SATURDAY.
IN...FLASH FLOOD WATCH...INZ010-INZ011-INZ019 UNTIL 7 PM SATURDAY.
LM...DENSE FOG ADVISORY...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ868-LMZ870-
LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 9 PM 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 LOUISVILLE KY
120 PM EDT SAT JUN 01 2013
...Updated Aviation Discussion...
.Forecast Update...
Issued at 940 AM EDT Sat Jun 1 2013
Quite a bit of stratiform rain remains over portions of southern
Indiana and west central Kentucky this morning in the wake of the
line of storms early this morning. Showers further to the south are
a bit more convective in nature. Have updated the grids to reflect
the current radar trends and take the chances for thunderstorms this
morning down to isolated. It still looks like we could see more
convection developing this afternoon, though the best chances for
strong to severe storms looks to be over southern and eastern
portions of the region where cloud cover is less and more
instability can develop. There is still quite a bit of uncertainty
in the forecast and it will need to be monitored closely today to
see how things evolve.
&&
.Short Term (Now through Sunday)...
Issued at 309 AM EDT Sat Jun 01 2013
Rather complex forecast unfolding early this morning, as incoming
convection casts quite a bit of uncertainty onto the forecast for
this afternoon into the overnight hours. All of this action is in
response to an expansive upper-level low, which will accelerate into
the Great Lakes this afternoon. An associated cold front will slide
through the region this evening through the overnight hours,
allowing drier and cooler conditions to work in for Sunday.
An expansive MCS continues to slide southeast across portions of
Missouri/Illinois/Indiana this morning. This activity continues to
be fueled by a 40-50 knot low-level jet, supplying copious amounts
of moisture. Some of this activity has briefly caused some
marginally severe wind gusts. However, 0-3km shear vectors oriented
mainly parallel to the cold pool is prohibiting intense upright
convection along the gust front, thus keeping the severe threat
rather isolated. Nonetheless, an isolated severe storm or two
cannot be ruled out within small bowing segments as it approaches
from the northwest early this morning.
The major question then becomes how quickly this morning activity
dissipates/pushes east, and what effect that will have on
instability this afternoon and evening. Guidance is all over the
place, with the latest RAP guidance still depicting 2500 J/kg of
MLCAPE developing late this afternoon ahead of the cold front.
Think the NAM/GFS are more realistic, painting anywhere from about
800-1400 J/kg by late this afternoon. This parameter will be
paramount in determining the severe risk throughout the day, as
lingering clouds/precipitation through the day will largely mitigate
the severe risk. Most of the hi-res guidance focuses the best
instability across southern Kentucky, as this area is most likely to
be unaffected by this approaching morning MCS. This will create a
split across the CWA, with the better dynamics focused across
southern IN/northern KY, while the best instability will reside
across southern Kentucky. Regardless, as the main shortwave ejects
out of the larger scale trough and spreads height falls over the
synoptic cold front, widespread convection looks to break out late
this afternoon into the evening, especially across southern KY.
0-6km shear of 30-40 knots will favor organized convection across
the entire region. The accelerating cold front and large-scale
forcing for ascent will favor mainly a linear storm mode, although a
transient supercell structure will be possible as storms initially
develop. 0-1km shear values of 25-35 knots will promote at least
some tornado risk, although surface winds do not appear as if they
will be quite as backed (SSE) as was suggested in previous model
runs, thus lower 0-1SRH is forecast. Large hail will also be
possible, especially across southern Kentucky where the best
instability will reside, but the expected QLCS storm mode may temper
that threat as well. The bottom line: The severe threat will
largely hinge on afternoon destabilization. If we can destabilize,
a severe QLCS capable of mainly damaging winds will materialize.
Large hail and a few isolated tornadoes will also be possible. Stay
tuned to the forecast throughout the day as the details regarding
the decaying MCS and resulting instability become more apparent.
The synoptic cold front will push through by Sunday evening. Some
guidance is showing the potential for a few showers across southern
IN as the main trough axis swings through Sunday evening, but will
keep the forecast dry for now as moisture looks limited. Highs
Sunday will reach the upper 70s to lower 80s with westerly flow.
.Long Term (Sunday Night - Friday)...
Issued at 230 AM EDT Sat Jun 1 2013
No major changes, as an exiting front will bring lingering rains
only over the far eastern forecast area, as an upper trough passes.
Forecast highs for Monday will be roughly 5 degrees below normal,
under a brief thickness minimum that will allow for pleasant
readings through Tuesday. Upper ridge builds in Wednesday, so kept
low/nil rain chances through at least then, but temperatures will go
over climo slightly by the end of the work week. Lows will rise
uniformly Wednesday through Friday. Morning readings should start to
go above normal Thursday. Storm chances enter the picture again as
heights fall and moisture increases Thursday and Friday. Coverage
should be scattered, mainly during peak heating.
&&
.Aviation (18Z TAF Issuance)...
Issued at 120 PM EDT Sat Jun 01 2013
The TAF forecast remains tricky for this afternoon and evening due
to uncertainty with storm development. Clouds and precipitation have
kept instability to a minimum over SDF and BWG through the morning.
However, clouds are beginning to break up this afternoon. In
addition most of the short term models develop a line of
thunderstorms this afternoon to the west of the area and bring them
across all terminals from the late afternoon through the evening
hours. Have therefore kept VCTS in the forecast for all the TAF
sites, but tried to refine the window of storm opportunity tonight
somewhat.
The storms should move out by early tomorrow morning. Cloud cover
will hang around and MVFR cigs will look to develop at least at BWG
and LEX towards sunrise. Bases should begin to lift through the day
tomorrow.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
KY...NONE.
$$
Update...........EER
Short Term.......KD
Long Term........RJS
Aviation.........EER
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
300 PM EDT SAT JUN 1 2013
.SYNOPSIS...
HIGH PRESSURE REMAINS ANCHORED OFF THE MID ATLANTIC COAST THROUGH
SUNDAY. A COLD FRONT SLOWLY CROSSES THE AREA MONDAY AND MONDAY NIGHT
THEN MOVES OFF THE COAST EARLY TUESDAY.
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
CRNT FCST ON TRACK AS STRNG RIDGE REMAINS OFF THE COAST. HIGH RES
MODELS DVLP CONVECTION OVR MTS AFTR 18Z. HOWEVER...DATA SPRTS THIS
CONVECTION WEAKENING AND OR DSPTG B4 GETTING INTO AKQ CNTYS. THIS
SPRTD BY THE CAP ON 12Z SNDGS. RUC ACTUALLY INDCTG SOME MSTR DVLPNG
ACROSS SERN VA / NE NC ARND 21Z DUE TO MERGING SEA BREEZE BNDRYS.
WILL MONITOR RADAR TRENDS AS DAY WEARS ON...BUT FOR NOW KEPT A DRY
FCST THIS AFTRN AND EVE. POP CAPPED AT 14%. HIGH TMPS U80S-L90S
XCPT COOLER AT THE BEACHES.
M CLR TO PT CLDY TONIGHT. LOWS IN THE U60S TO ARND 70.
&&
.SHORT TERM /6 AM SUNDAY MORNING THROUGH TUESDAY/...
A COLD FRONT WILL APPROACH FROM THE WEST ON SUNDAY. AS THE FRONT
ENCOUNTERS THE AFOREMENTIONED RIDGE...IT WILL SLOW DOWN AND EVEN
STALL ACROSS THE MID ATLANTIC STATES MONDAY. THE EURO IS A GOOD
COMPROMISE BETWEEN THE FASTER GFS AND SLOWER NAM.
PCPN WILL GRADUALLY DEVELOP FROM THE WEST SUNDAY AFTN AND SUNDAY
NIGHT. MODERATE INSTABILITY WILL RESULT IN SCATTERED TSTMS OVER
FAR WRN COUNTIES SUNDAY AFTN. THIS WILL BE AIDED BY UPPER LEVEL
DIVERGENCE ...A RESULT OF A NEGATIVELY TILTED UPPER LEVEL TROUGH
OVER THE EASTERN GREAT LAKES. MOST OF THE DIVERGENCE WILL BE TO
OUR NORTH. PCPN BECOMES LIKELY OVER MUCH OF THE NRN AND WRN
PORTIONS OF THE CWA OVERNIGHT SUNDAY NIGHT AND THUNDERSTORMS WILL
BE PSBL. FAR SE PORTIONS SHOULD REMAIN DRY THROUGH EARLY MONDAY
MORNING.
HAVE LIKELY POPS ACRS ALL BUT FAR SE PORTIONS DURING THE DAY MONDAY
AS THE FRONT BECOMES DIFFUSE OVER THE MID ATLANTIC STATES. DID NOT
WANT TO GO CATEGORICAL POPS AS MOS POPS ARE GENERALLY FROM 50 TO
60 PERCENT.
AN UPR LEVEL SPEED MAX TO THE NORTH AND POCKETS OF INSTABILITY
DURING THE DAY MONDAY WILL RESULT IN THE POSSIBILITY OF SCATTERED
EMBEDDED THUNDERSTORMS. PCPN WILL BE SLOW TO DEPART THE AREA FROM
WEST TO EAST MONDAY NIGHT. BY TUESDAY MORNING...THE FRONT BECOMES
BETTER DEFINED AND MOVES OFFSHORE. THE AREA SHOULD BE DRY EXCEPT
IN THE SE VA AND NE NC WHERE SHOWERS SHOULD END BY MIDDAY. THE
NAM KEEPS PCPN IN THE AREA LONGER BUT THIS IS IN THE OUTER RANGE
OF THAT MODEL WHICH IS GENERALLY LESS RELIABLE THAN EARLIER
PORTIONS OF THE MODEL.
PRECIPITABLE WATER ACCORDING TO THE NAM INCREASES TO BETWEEN 1.7 AND
2.0 INCHES ON MONDAY. THIS SHOULD RESULT IN A GOOD SOAKING. WPC QPF
FORECASTS HAVE INCREASED RAINFALL FOR THE AREA IN ASSOCIATION WITH
THE PCPN EVENT LATE SUNDAY THROUGH EARLY TUESDAY. HAVE BLENDED
THEIR FORECAST INTO OURS WHICH RESULT IN THREE QUARTERS TO ONE AND
A HALF INCHES TOTAL PCPN ACROSS THE CWA. LATER FORECASTS MAY NEED
TO BUMP THE QPF HIGHER.
DAYTIME TEMPERATURES WILL LOWER SLIGHTLY SUNDAY WITH HIGHS IN THE
MID TO UPR 80S. WITH PCPN AND CLOUD COVER...TEMPERATURES ON MONDAY
WILL RUN FROM NEAR 80 TO THE MIDDLE 80S. MAXIMUM READINGS ON TUESDAY
ARE EXPECTED TO REACH THE MID TO UPR 70S WITH NEAR 80 DEGREES IN THE
SOUTHERN VIRGINIA PIEDMONT. LOWS WILL BE IN THE MID TO UPR
60S...LOWERING TO AROUND 60 OVER THE PIEDMONT TUESDAY MORNING.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
HI PRES WILL BLD FM THE GRT LKS EWRD INTO NEW ENGLAND TUE AFTN INTO
THU MORNG...THEN SLIDE OFF THE NEW ENGLAND CST FOR THU AFTN THRU
FRI. WILL MAINTAIN A DRY FCST THRU THE EXTENDED PERIOD WITH
COMFORTABLE TEMPS/HUMIDITY AT LEAST FOR TUE INTO THU. MIN TEMPS WILL
BE IN THE MID 50S TO LWR 60S WED AND THU MORNGS...AND IN THE UPR 50S
TO MID 60S FRI MORNG. MAX TEMPS WILL BE IN THE MID 70S TO LWR 80S
WED AND THU...AND IN THE UPR 70S TO MID 80S FRI.
&&
.AVIATION /19Z SATURDAY THROUGH THURSDAY/...
STRONG S-SW FLOW CONTINUES OVER THE REGION. A FEW SHRAS/TSTMS
DEVELOPING FAR WEST NEAR LEE OF THE MNTS...BUT NO WX EXPECTED FOR
THE CWA FOR THE NEXT 24-36 HRS. MODELS SHOW SOME INCREASE IN
GRADIENT WINDS ON SUNDAY SO EXPECT SFC WINDS TO BE MORE
GUSTY...MAYBE 20-25 KT DURING THE DAY.
GUIDANCE INDICATING A SLIGHTLY BETTER CHANCE FOR LOW CLOUDS EARLY
SUNDAY MORNING...BUT SKEW-T AND LACK OF 925 MB MOISTURE GIVES ME LOW
CONFIDENCE IN THIS HAPPENING SO DECIDED NOT TO INDICATE STRATUS IN
THE TAFS. EXPECT CONT VFR CONDS THRU THE NIGHT AND SUNDAY. SCATTERED
SHRA/TSRA WILL BE POSSIBLE BY SUNDAY EVENING...AND BECOME LIKELY
ON MONDAY. DRY/VFR CONDITIONS RETURN FROM NW TO SE ON TUE (SOME
SHRA/LOW CLOUDS MAY LINGER THROUGH MIDDAY TUE AT KORF/KECG).
DRY/VFR TUE NIGHT-WED IN NE FLOW.
&&
.MARINE...
WILL NOT HAVE ANY HEADLINES ON THIS FCST ISSUANCE...BUT MAY NEED
SCA`S FOR SEAS ON THE THREE NRN CSTL ZNS LATER ON FOR TONIGHT INTO
MON...AND INCREASING SOUTHERLY FLOW MAY GET CLOSE TO SCA CRITERIA
TONIGHT (ALTHOUGH EXPECT ANY GUSTS TO 20 KT TO BE BRIEF/NOT
FREQUENT ENOUGH FOR SCA HEADLINES IN THE BAY). OTHERWISE...HIGH PRES
WILL REMAIN ANCHORED OFF THE MID ATLC CST INTO AT LEAST MON
MORNG...WITH S/SW WINDS AVERAGING 10 KT TODAY...15 KT
TONIGHT/SUNDAY (15 TO 20 KT ON THE COAST TONIGHT THRU SUN NIGHT). A
COLD FRONT WILL PUSH ACRS THE WTRS AND OFF THE CST MON THRU TUE.
WINDS WILL SHIFT TO THE NW THEN NNE AVERAGING AROUND 15 KT (BUT
WILL PROBABLY SEE A BRIEF SURGE OF HIGHER WINDS AND AS TIMING
BECOMES MORE CERTAIN MAY SEE LOW END SCA CONDITIONS FOR A FEW
HOURS AS THE HIGH BUILDS IN FROM THE NW EARLY TUE OR AGAIN TUE
NIGHT/EARLY WED.
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...SMALL CRAFT ADVISORY FROM MIDNIGHT TONIGHT TO 6 AM EDT MONDAY
FOR ANZ650-652.
&&
$$
SYNOPSIS...LSA
NEAR TERM...MPR/LSA
SHORT TERM...LSA
LONG TERM...TMG
AVIATION...JEF
MARINE...LKB
AREA FORECAST DISCUSSION
NWS GAYLORD MI
103 PM EDT SAT JUN 1 2013
.SYNOPSIS...
ISSUED AT 258 AM EDT SAT JUN 1 2013
LOW PRESSURE WILL MOVE EAST FROM MINNESOTA...CROSSING NORTHERN
MICHIGAN TONIGHT. UNSETTLED WEATHER WILL CONTINUE THRU SUNDAY
MORNING...BEFORE THIS SYSTEM DEPARTS. MUCH COOLER AND DRIER AIR
WILL ENTER THE REGION BEHIND THE DEPARTING LOW. A COUPLE OF
FROSTY MORNINGS ARE POSSIBLE ON BOTH MONDAY AND TUESDAY.
&&
.UPDATE...
ISSUED AT 102 PM EDT SAT JUN 1 2013
SPOTTY SHOWER WITH PERHAPS SOME THUNDER CONTINUES ACROSS THE
CWA...ESPECIALLY NORTH...ALTHOUGH ACTIVITY HAS BEEN DWINDLING
OVERALL. SFC DEWPOINTS STILL RUNNING ON THE HIGHER SIDE. BUT NO
MATTER AS ABUNDANT CLOUD COVER IS KEEPING TEMPS AND RESULTING
INSTABILITY WAY IN CHECK. NO SIGNS OF THINNING IN THE CLOUD COVER
FOR THE NEXT FEW HOURS ANYWAY. THUS STILL BELIEVE THAT MOST AREAS
WILL REMAIN DRY THROUGH MUCH OF THE AFTERNOON SAVE FOR SOME
ISOLATED STUFF.
LOOKING TO THE WEST...SOME SEMBLANCE OF A DRY SLOT FROM WISCONSIN
DOWN INTO THE MIDWEST. THIN LINE OF SHOWERS/STORMS JUST STARTING
TO GO ACROSS THAT AREA DUE TO DIFFERENTIAL HEATING AND APPROACHING
SFC LOW AND MID LEVEL HEIGHT FALLS. THIS WILL BE THE NEXT ROUND OF
SHOWERS/THUNDER THAT WILL ULTIMATELY SPREAD INTO THE REGION THIS
EVENING.
UPDATE ISSUED AT 1033 AM EDT SAT JUN 1 2013
ANOTHER TOUGH FORECAST FOR THE AFTERNOON/EARLY EVENING TIMEFRAME
ON WHAT IS SURELY A BUSY OUTDOOR WEEKEND. EARLY MORNING CONVECTION
NOW ROLLING UP THROUGH EASTERN UPPER MICHIGAN. CONVECTION WAS THE
RESULT OF COMPACT MCV (RADAR REFLECTIVITY PATTERN REVEALS THE
SPIN) THAT BROKE AWAY FROM LAST EVENINGS CONVECTION IN THE
MIDWEST AND PUSHED UP THROUGH THE REGION EARLY THIS MORNING. STILL
A FEW POCKETS OF SHOWERS TRAILING THE MCV ACROSS NRN LOWER
MICHIGAN.
FOR THIS AFTERNOON...AGAIN...TOUGH FORECAST. AS MENTIONED ABOVE...
BEHIND THE DEPARTING MCV ISOLATED SHOWERS AND THUNDER CONTINUES TO
POP UP ACROSS NRN AND CENTRAL LOWER MICHIGAN DESPITE LOWER VALUES
OF INSTABILITY...EVIDENCE OF THE UNCAPPED ENVIRONMENT STILL IN
PLACE. QUESTION IS...WILL ONGOING ACTIVITY CONTINUE TO GROW
UPSCALE AS WE SLOWLY HEAT UP. NAM AND RUC FORECAST SOUNDINGS DO
REVEAL A WINDOW OF OPPORTUNITY THROUGH EARLY TO MID AFTERNOON
WITH BETWEEN 500 AND 1000 J/KG MLCAPE ACROSS NRN LOWER MICHIGAN
AND LITTLE TO NO CINH. BUT SIMILAR TO YESTERDAY...BOTH NAM AND GFS
SOUNDINGS SUGGEST MIXING WILL ULTIMATELY TAP DRIER AIR ALOFT AND
DROP SFC DEWPOINTS BACK INTO 50S TO LOWER 60S. SO...GUT FEELING IS
WE CONTINUE TO SEE ISOLATED-SCT SHOWERS/THUNDER THROUGH EARLY TO
MID AFTERNOON BEFORE ACTIVITY GETS SQUASHED. WILL GO THAT ROUTE
FOR NOW AND JUST SEE WHAT HAPPENS.
UPDATE ISSUED AT 659 AM EDT SAT JUN 1 2013
GRIDS UPDATED TO ACCOUNT FOR WELL-DEFINED BAND OF CONVECTION
LIFTING ACROSS NW/N CENTRAL LOWER MI. APX DOPPLER SHOWED SOME
HIGHLY LOCALIZED 50KT INBOUNDS 15-20SM SW OF THE RADAR AS THE
STORMS APPROACHED...BUT NO SURPRISE (GIVEN A SLIGHTLY STABLE
BOUNDARY LAYER) THAT THOSE WINDS ARE NOT GETTING TO THE GROUND.
&&
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 258 AM EDT SAT JUN 1 2013
CURRENTLY, THERE IS A 850 MB THETA-E GRADIENT THAT RUNS N ILLINOIS
THROUGH LAKE MICHIGAN, INTO E UPPER, AND THEN INTO ONTARIO NORTH OF
ANJ. THE SHOWERS (MAYBE A THUNDERSTORM, ALTHOUGH NO CG STRIKES WERE
OBSERVED) HAVE BEEN MOVING WITH THAT BOUNDARY OVERNIGHT, WHICH ARE
JOINING UP WITH THE THUNDERSTORMS THAT ARE NOW OVER LAKE SUPERIOR
THAT WERE OVER W UPPER LAST EVENING. WITH THE 1000-850 MB LAYER WIND
OUT OF THE SSW, AND THE SHOWERS LOOK TO BE RIDING ALONG THOSE WIND
STREAMLINES, IT LOOKS LIKE WE WILL GET A BREAK THIS MORNING IN N
LOWER, WITH SCATTERED SHOWERS IN E UPPER.
TODAY...THIS IS STILL A SOMEWHAT COMPLICATED FORECAST, SINCE THERE
IS SOME UNCERTAINTY TO WHETHER THE BREAK THAT I ALLUDED TO WILL LAST
AS LONG AS WILL BE STATED. HOWEVER, BASED ON THE CURRENT TRENDS AND
THE LATEST MODELS, HERE`S WHAT LOOKS LIKE SHOULD HAPPEN. THE FIRST
THING THAT WILL BLOCK MOST OF THE CONVECTION IN OUR AREA IS THE
ONGOING CONVECTION DOWN SOUTH ALONG THE INDIANA/OHIO/MICHIGAN
BORDER. AS IT PROGRESSES EAST, THE MOISTURE AND ENERGY TRANSPORT
WILL BE CUT OFF TO ALLOW ANYTHING TO GET GOING IN NW LOWER AND E
UPPER. HOWEVER, SOME OF THE SHOWERS AND THUNDERSTORMS LOOKS LIKE
THEY MAY TRY TO SLIDE NORTH ALONG THE THETA-E BOUNDARY INTO NE LOWER
THIS MORNING. OTHERWISE, TO THE WEST, THERE IS A PRETTY HEFTY AREA
OF DRIER AIR WITH THE DEWPOINTS IN THE MID 50S(IN WISCONSIN), AND
RUNNING THE HYSPLIT MODEL BACKWARDS TO SEE WHERE THE AIR MASS IS
ORIGINATING FROM SHOWS A MIXTURE OF LOWER TO MID 60S DEWPOINTS FROM
SW LOWER(SURFACE AIR), AND LOWER DEWPOINTS (MID 40S) FROM SW IOWA
(1000 METER AGL AIR). THIS WOULD AGREE WITH THE GFS/NAM/ECMWF IDEA
OF A DRY SLOT WORKING INTO THE REGION AND PUTTING THE BREAKS ON THE
SHOWERS DURING THE DAY IN E UPPER AND NW LOWER, AND AS THE SFC LOW
MOVES EAST, THE DRY SLOT WILL WORK ITS WAY EAST AND PUSH THE THUNDER
POTENTIAL EAST, AS WELL. BY THE LATE AFTERNOON, MOST OF N LOWER WILL
BE IN THE DRIER AIR WITH THE THUNDER POTENTIAL WORKING ITS WAY BACK
INTO E UPPER AS THE BACK EDGE OF THE LOW PROVIDES SOME FORCING IN
THE INITIALLY WARM AIR MASS.
TONIGHT...AS THE LOW CONTINUES TO MOVE EAST, THE COOLER AIR BEGINS
TO MOVE INTO THE REGION. THIS WILL ALLOW FOR SHOWERS FROM THE 500 MB
TROUGH (AND THE MOISTURE ASSOCIATED WITH IT) TO PUSH INTO THE
FORECAST AREA. SINCE THIS IS AT NIGHT (NO SFC INSTABILITY), AND THE
700-500 MB LAPSE RATES ARE AROUND 6 C/KM, THINK THAT THE THUNDER
POTENTIAL GOES TO ZERO WITH RAIN SHOWERS EXPECTED IN THE COLD AIR.
THIS CONTINUES INTO THE NIGHT AND SPREADS TO THE SE COUNTIES BY 12Z.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 258 AM EDT SAT JUN 1 2013
OUR WX QUICKLY TURNS MUCH QUIETER...BUT MUCH COOLER...TO CLOSE OUT
THE WEEKEND. PRIMARY TROF EXTENDING FROM 500MB LOW NORTH OF SUPERIOR
WILL BE RIGHT OVERHEAD ON SUNDAY MORNING...AND WILL QUICKLY EJECT TO
THE EAST...EVEN AS THE UPPER LOW DIGS A BIT TOWARD SUPERIOR/S NORTH
SHORE. THIS LOW REMAINS PROGRESSIVE...PASSING JUST SOUTH OF JAMES
BAY MONDAY MORNING. 500MB SHORTWAVE RIDGING WILL GET PUMPED UP INTO
THE AREA BY TUESDAY MORNING...IN ADVANCE OF ENERGY MOVING INTO THE
DAKOTAS. OTHER THAN ANY LINGERING PRECIP CHANCES AT THE START OF THE
DAY SUNDAY...THE MAIN CHALLENGE IS MIN TEMPS AND ANY EARLY JUNE
FROST POTENTIAL.
SUNDAY...COLD ADVECTION WILL BE UNDERWAY ACROSS ALL OF NORTHERN MI
AT 12Z SUNDAY. DEEPER MOISTURE WILL BE DEPARTING SOON THEREAFTER...
BUT NOT QUITE IMMEDIATELY. HAVE SOME CONCERNS THAT THE NAM (AS IT
LIKES TO DO) IS OVERDOING THE LOW-LEVEL MOISTURE PRESENT UP TIL 18Z.
BUT GIVEN THE 500MB TROF AXIS IS ONLY ALONG A NEWBERRY-TVC AXIS AT
DAYBREAK...WOULD CERTAINLY STILL MAKE SENSE FOR SOME EARLY AM SHRA
TO LINGER. WILL KEEP THINGS SIMPLE...WITH A CHANCE OF -SHRA ACROSS
THE AREA SUNDAY MORNING. SHARPLY DRIER AIR ARRIVES IN THE PM...WITH
850-700MB RH LEVELS BELOW 40 PERCENT. WILL REMOVE PM POPS. THAT
DRIER AIR WILL SERIOUSLY ERODE LINGERING COLD-AIR STRATOCU...
ESPECIALLY BY LATE AFTERNOON/EARLY EVENING. 850MB TEMPS TUMBLE TO
AROUND 1C BY EVENING...WHICH WILL PUT THE KIBOSH ON TEMPS GOING MUCH
OF ANYWHERE IN THE PM HOURS. THE NE LOWER COAST SHOULD STILL SHOOT
INTO THE LOW-MID 60S TO START THE DAY...ELSEWHERE HIGHS WILL BE IN
THE 50S.
SUN NIGHT/MONDAY...A POCKET OF DEEP MOISTURE WRAPPED AROUND THE
UPPER LOW WILL BE TUCKED JUST NORTH OF THE SAULT SUNDAY NIGHT INTO
MONDAY. BUT THE NAM/GFS AGREE THAT IT NEVER QUITE PINWHEELS DOWN
INTO EASTERN UPPER. SUPERIOR IS OF COURSE STILL VERY CHILLY (EASTERN
BUOY WATER TEMP IS 38F)...SO 850MB TEMPS NOSING DOWN PERHAPS AS LOW
AS -2C WILL NOT PROMPT A LAKE RESPONSE. SO CAN KEEP THESE PERIODS
DRY. EASTERN UPPER WILL GET GRAZED BY LOW/MID CLOUDS SWIRLING AROUND
THE PASSING LOW...NORTHERN LOWER WILL SEE LITTLE CLOUD COVER DURING
THESE PERIODS.
DOUBT THAT EASTERN UPPER AND THE NE LOWER MI COAST WILL DECOUPLE
SUNDAY NIGHT...AS THE PRESSURE GRADIENT REMAINS RATHER TIGHT THERE.
THE BULK OF NORTHERN LOWER LIKELY WILL...AS THE CENTER OF THE
UPSTREAM SURFACE HIGH DRIFTS FROM IOWA TOWARD CHICAGO. A LITTLE BIT
OF CLOUD COVER AND BREEZE WILL LIKELY KEEP EASTERN UPPER MIN TEMPS
IN THE MID TO UPPER 30S. NORTHERN LOWER WILL VARY MORE
SUBSTANTIALLY...NEAR 40F ALONG SOME COASTS BUT DIPPING DEEP INTO THE
30S IN INTERIOR COLD SPOTS (DEFINITELY THE AU SABLE VALLEY). WILL
FINE-TUNE FROST COVERAGE IN THE GRIDDED FORECASTS. BUT SUFFICE TO
SAY THERE IS A VERY GOOD CHANCE OF SEEING THAT FROST IN THE USUAL
INTERIOR COOL SPOTS (WHICH...FOR THOSE LOCATIONS...ISN/T THE LEAST
BIT UNUSUAL FOR THE 1ST WEEK OF JUNE).
NOT A LOT OF MODERATION IN THE AIRMASS FOR MONDAY. 850MB TEMPS STILL
RANGING FROM NEAR 0C IN EASTERN UPPER TO 2C IN SOUTHERN SECTIONS AT
MIDDAY. BUT LOTS OF SUNSHINE (ESPECIALLY IN NORTHERN LOWER) WILL
HELP. MAX TEMPS UPPER 50S EASTERN UPPER TO MID 60S IN SOUTHERN
SECTIONS.
REST OF THE FORECAST...ANOTHER CHILLY/POTENTIALLY FROSTY NIGHT ON
MONDAY NIGHT...WITH TEMPS IN ABOUT THE SAME BALLPARK AS SUNDAY
NIGHT. IN FACT...TEMPS LOOK TO REMAIN BELOW CLIMO THRU THE
FORECAST...AS A SERIES OF UPPER TROFS MIGRATING ACROSS THE NORTHERN
STATES KEEP SUMMER TEMPS AT BAY. QUIET WX WILL CONTINUE INTO TUESDAY
NIGHT...BEFORE SHOWER CHANCES ARRIVE WEDNESDAY. SMALLISH RAIN
CHANCES WILL LAST THRU THE REST OF THE WORK WEEK...AS THE NEXT UPPER
TROF SLOWLY TRANSITS THE REGION.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 102 PM EDT SAT JUN 1 2013
MVFR CIGS DOMINATE ACROSS NRN LOWER MICHIGAN CURRENTLY...WITH NO
SIGNS OF IMPROVEMENT AT THIS POINT. CIGS MAY TEND TO INCREASE THIS
AFTERNOON AS HEATING PROCEEDS. NEXT ROUND OF SHOWERS AND SOME
THUNDER WILL SPREAD INTO THE REGION THIS EVENING AND OVERNIGHT AS
A COLD FRONT SWEEPS THROUGH THE STATE. EXPECT CIGS TO DIP BELOW 1K
FEET OVERNIGHT AS COLDER AIR SLICES INTO THE REGION. SHOWERY
PRECIP PERSISTS THROUGH SUNDAY MORNING WITH CLEARING/BIG
IMPROVEMENT IN THE AFTERNOON.
&&
.MARINE...
ISSUED AT 258 AM EDT SAT JUN 1 2013
WINDS WILL REMAIN BELOW SMALL CRAFT CRITERIA AS THE SFC GRADIENT
NEVER QUITE TIGHTENS UP ENOUGH TO GET ANY WIND GOING. THE SFC LOW
MOVES IN TONIGHT, WHICH KEEPS THE GRADIENT SLACK. BY SUNDAY, THE
GRADIENT TIGHTENS BACK UP, BUT SHOULD REMAIN JUST BLOW SMALL
CRITERIA, UNTIL THE LATE AFTERNOON WHEN THE GRADIENT TIGHTENS UP
MORE, AND SMALL CRAFT WIND GUSTS ARE EXPECTED. THIS WILL LAST INTO
SUNDAY NIGHT.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...NONE.
LM...NONE.
LS...NONE.
&&
$$
UPDATE...BA
SYNOPSIS...JZ
SHORT TERM...JL
LONG TERM...JZ
AVIATION...BA
MARINE...JL
AREA FORECAST DISCUSSION
NWS BUFFALO NY
613 PM EDT SAT JUN 1 2013
.SYNOPSIS...
A COLD FRONT WILL GRADUALLY APPROACH FROM THE UPPER LAKES
TONIGHT...CROSSING THE REGION LATE ON SUNDAY. THIS WILL BRING AN
INCREASING CHANCE FOR SHOWERS AND THUNDERSTORMS TONIGHT INTO
SUNDAY...WITH LOCALLY HEAVY DOWNPOURS POSSIBLE. COOLER AND DRIER AIR
WILL BUILD INTO THE REGION FOR THE FIRST HALF OF THE WEEK.
&&
.NEAR TERM /THROUGH SUNDAY/...
THROUGH EARLY EVENING...ATTENTION REMAINS ON A LINE OF
THUNDERSTORMS MOVING ACROSS WESTERN NEW YORK. THIS LINE IS
ASSOCIATED WITH AN AREA OF UPPER LEVEL MOISTURE...WHICH CAN BE
SEEN EXTENDING FROM NORTH TO SOUTH ON THE IR SATELLITE IMAGERY.
THIS HAS SERVED AS A FOCUS FOR CONVECTIVE INITIATION. WIND
PROFILES SHOW A FAIR AMOUNT OF SHEAR...WITH 850 MB WINDS
INCREASING TO 40 KTS. STORMS HAVE DEVELOPED INTO LINEAR BOWING
SEGMENTS...WHICH IS CONSISTENT BUT A TAD FASTER THAN THE PAST
COUPLE RUNS OF THE HRRR. FOLLOWING THIS...EXPECT CONTINUED ACTIVE
WEATHER THROUGH SUNSET...WITH THUNDERSTORMS LIKELY TO GRADUALLY
WEAKEN WITH THE LOSS OF DAYTIME HEATING. THIS SAID...MOMENTUM COULD
ALLOW STRONG STORMS TO HOLD TOGETHER INTO THE EVENING HOURS. AT
THIS POINT...WIND DAMAGE APPEARS TO BE THE MAIN THREAT WITH THESE
THUNDERSTORMS.
FORECAST CONFIDENCE INCREASES LATER TONIGHT...DUE TO A STRONGER
MODEL CONSENSUS. WITH THE HRRR ALSO LENDING SUPPORT THE OTHER
GUIDANCE (NAM/RGEM/SREF/GFS)...THERE IS A HIGH CONFIDENCE IN
SHOWERS AND THUNDERSTORMS MOVING IN FROM WEST TO EAST LATE TONIGHT
AS AN UPPER TROF GETS CLOSER. A STRONG MODEL CONSENSUS SHOWS SOME
MEASURABLE QPF IN WESTERN SECTIONS BY DAYBREAK SUNDAY...AND GIVEN
THE SYNOPTIC FEATURE THIS MAKES SENSE. LATER TONIGHT...THERE IS A
POTENTIAL FOR HEAVY RAIN...WITH PWATS FORECAST TO INCREASE TO
1.75 INCHES BY BOTH THE NAM/GFS.
TEMPERATURES SHOULD ONLY DROP INTO THE UPPER 60S OVERNIGHT...AS
WINDS/CLOUDS AND RAIN LIMIT RADIATIONAL COOLING. HIGHS ON SUNDAY
SHOULD BE NOTABLY COOLER..RANGING FROM THE 70S IN WESTERN
SECTIONS TO LOWER 80S ACROSS THE GENESEE VALLEY AND FINGER LAKES REGIONS.
SHOWERS AND THUNDERSTORMS SHOULD TAPER OFF FROM WEST TO EAST ON
SUNDAY. THIS ACTIVITY IS LIKELY TO BE ALONG A PRE-FRONTAL
TROF...WITH THE ACTUAL FRONT AND WIND SHIFT LIKELY TO HOLD OFF UNTIL
LATER IN THE DAY. THIS MAY SPARK AN ADDITIONAL SHOWER...WITH A
SIGNIFICANT BREAK OF FAIR WEATHER POSSIBLE BETWEEN THE PRE-FRONTAL
TROF AND THE FRONT ITSELF.
&&
.SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY NIGHT/...
THE CLOSED UPPER LOW OVER ONTARIO PROVINCE BETWEEN THE NORTHERN
GREAT LAKES AND JAMES BAY WILL MOVE EAST SUNDAY NIGHT AS A
POSTFRONTAL SURFACE RIDGE BUILDS ACROSS NEW YORK STATE. THIS WILL
CLEAR OUT LOW LEVEL DEWPOINTS FROM THE UPPER 50S TO 60 DEGREES
SUNDAY EVENING...TO THE MID 40S TO LOW 50S BY DAYBREAK ON MONDAY.
THERE WILL ALSO BE A CLEARING TREND WITH THE INFLUX OF THE DRIER
AIRMASS AND COLD ADVECTION WILL BRING OVERNIGHT LOWS TO THE UPPER
40S TO LOW 50S.
SURFACE HIGH PRESSURE CENTER OVER SOUTHERN ONTARIO PROVINCE WILL
PROVIDE A DRY AND COOL PERIOD FOR THE FIRST HALF OF THE WEEK WITH
POPS NEAR ZERO AND ABUNDANT SUNSHINE. HIGH TEMPS WILL BE IN THE
LOWER TO MIDDLE 60S AT THE START OF THE WEEK AND NUDGE UP TO THE MID
AND UPPER 60S ON TUESDAY. DRY AIR AND CLEAR SKIES AT NIGHT WILL
ALLOW LOW TEMPS TO FALL TO THE LOWER TO MID 40S FOR MOST OF THE AREA
MONDAY NIGHT AND MOSTLY IN THE MID TO UPPER 40S FOR TUESDAY NIGHT.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
THE CENTER OF THE SURFACE HIGH ACROSS SOUTHERN ONTARIO WILL MOVE
EASTWARD AND ALLOW A SOUTHERLY FLOW ACROSS THE FORECAST AREA. THIS
WILL BRING A MIDWEEK WARMING TREND WITH HIGH TEMPS RETURNING TO NEAR
NORMAL READINGS IN THE LOWER TO MID 70S. OVERNIGHT LOWS WILL ALSO
MODERATE TO NEAR OR ABOVE NORMAL READINGS...RANGING FROM THE LOWER
TO MID 50S WEDNESDAY NIGHT TO THE MID AND UPPER 50S THURSDAY NIGHT
AND FRIDAY NIGHT.
THE RETURN OF WARMTH WILL ALSO BRING A RETURN OF HUMIDITY AND A FAIR
CHANCE OF RAIN FROM THURSDAY THROUGH SATURDAY. PRECIPITABLE WATER
VALUES WILL INCREASE FROM AROUND A HALF INCH AT MID WEEK TO MORE
THEN AN INCH AND A HALF BY THE END OF THE WEEK...THUS WE CAN EXPECT
THE POSSIBILITY OF DOWNPOURS ASSOCIATED WITH ANY CONVECTION.
&&
.AVIATION /22Z SATURDAY THROUGH THURSDAY/...
OUTSIDE OF SCATTERED SHOWERS AND THUNDERSTORMS...EXPECT MAINLY VFR
CONDITIONS FOR THE REMAINDER OF THE AFTERNOON. THIS RISK WILL BE
GREATEST LATE AFTERNOON...THEN BRIEFLY DIMINISH THIS EVENING
BEFORE INCREASING AGAIN LATER THIS EVENING. THESE WILL PROBABLY
BRING PERIODS OF MVFR CONDITIONS OR LOWER IN HEAVY RAIN. SHOWERS
AND THUNDERSTORMS SHOULD TAPER OFF FROM WEST TO EAST ON SUNDAY
MORNING.
OUTLOOK...
SUNDAY...VFR MUCH OF THE TIME...BUT OCCASIONAL SHOWERS AND
THUNDERSTORMS WILL PRODUCE LOCAL MVFR/IFR AT TIMES.
MONDAY-WEDNESDAY...VFR.
&&
.MARINE...
AN AREA OF LOW PRESSURE WILL PASS BY TO THE NORTH OF THE REGION
SUNDAY WITH A COLD FRONT CROSSING THE LOWER LAKES. WINDS WILL
INCREASE OUT OF THE SOUTHWEST ALONG AND BEHIND THIS COLD FRONT
WITH THE POTENTIAL FOR A PERIOD OF WINDS AND WAVES APPROACHING
SMALL CRAFT ADVISORY CRITERIA.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...APFFEL
NEAR TERM...APFFEL
SHORT TERM...WCH
LONG TERM...WCH
AVIATION...APFFEL
MARINE...APFFEL/WCH
AREA FORECAST DISCUSSION
NWS BUFFALO NY
514 PM EDT SAT JUN 1 2013
.SYNOPSIS...
A COLD FRONT WILL GRADUALLY APPROACH FROM THE UPPER LAKES
TONIGHT...CROSSING THE REGION LATE ON SUNDAY. THIS WILL BRING AN
INCREASING CHANCE FOR SHOWERS AND THUNDERSTORMS TONIGHT INTO
SUNDAY...WITH LOCALLY HEAVY DOWNPOURS POSSIBLE. COOLER AND DRIER AIR
WILL BUILD INTO THE REGION FOR THE FIRST HALF OF THE WEEK.
&&
.NEAR TERM /THROUGH SUNDAY/...
THROUGH EARLY EVENING...ATTENTION WILL REMAIN ON A BOUNDARY WHICH
EXTENDS ACROSS EASTERN LAKE ERIE...ACROSS THE NIAGARA
FRONTIER...AND ACROSS LAKE ONTARIO. THIS FEATURE HAS BEEN THE KEY
TO CONVECTIVE INITIATION...AND IT NOW APPEARS THAT THE SW FLOW WILL
NOT BE ENOUGH TO KEEP THE NIAGARA FRONTIER MIXED. SHOWERS AND
THUNDERSTORMS ARE LIKELY AS THIS BOUNDARY SLIDES EASTWARD...WITH
ACTIVITY LIKELY TO DIMINISH LATE THIS EVENING AS INSTABILITY DECREASES.
FORECAST CONFIDENCE INCREASES LATER TONIGHT...DUE TO A STRONGER
MODEL CONSENSUS. WITH THE HRRR LENDING SUPPORT THE OTHER GUIDANCE
(NAM/RGEM/SREF/GFS)...THERE IS A HIGH CONFIDENCE IN SHOWERS AND
THUNDERSTORMS MOVING IN FROM WEST TO EAST LATE TONIGHT AS AN UPPER
TROF GETS CLOSER. A STRONG MODEL CONSENSUS SHOWS SOME MEASURABLE QPF
IN WESTERN SECTIONS BY DAYBREAK SUNDAY...AND GIVEN THE SYNOPTIC
FEATURE THIS MAKES SENSE.
FORECAST WIND PROFILES SHOW 850 MB WINDS INCREASING FROM 35 KTS TO
45 KTS BY DAYBREAK SUNDAY. THIS COMBINED WITH SOME VEERING WITH
HEIGHT WILL RESULT IN MODEST SHEAR...WHICH WILL AID ORGANIZATION OF
ANY THUNDERSTORMS. THE SEVERE POTENTIAL IS BEST EARLY ON...SINCE
WINDS WILL STRUGGLE TO MIX DOWN THE LATER IN THE EVENING IT GETS.
THIS CONTINUES TO BEAR WATCHING...WITH BOTH GUSTY WINDS AND LARGE
HAIL POSSIBLE IN STRONG THUNDERSTORMS. AT THIS POINT...THE BEST
CHANCE FOR SEVERE STORMS WOULD BE IF LATE AFTERNOON STORMS ARE
ABLE TO DEVELOP ANY LINEAR STRUCTURE. ALTHOUGH WIDESPREAD SEVERE
WEATHER APPEARS UNLIKELY...WILL CONTINUE TO KEEP AN EYE AS STORMS
DEVELOP AND SPREAD TO INTERIOR SECTIONS WHERE INSTABILITY IS GREATER.
ANOTHER CONCERN IS THE POTENTIAL FOR HEAVY RAIN...WITH PWATS
FORECAST TO INCREASE TO 1.75 INCHES BY BOTH THE NAM/GFS.
TEMPERATURES SHOULD ONLY DROP INTO THE UPPER 60S OVERNIGHT...AS
WINDS/CLOUDS AND RAIN LIMIT RADIATIONAL COOLING. HIGHS ON SUNDAY
SHOULD BE NOTABLY COOLER..RANGING FROM THE 70S IN WESTERN
SECTIONS TO LOWER 80S ACROSS THE GENESEE VALLEY AND FINGER LAKES REGIONS.
SHOWERS AND THUNDERSTORMS SHOULD TAPER OFF FROM WEST TO EAST ON
SUNDAY. THIS ACTIVITY IS LIKELY TO BE ALONG A PRE-FRONTAL
TROF...WITH THE ACTUAL FRONT AND WIND SHIFT LIKELY TO HOLD OFF UNTIL
LATER IN THE DAY. THIS MAY SPARK AN ADDITIONAL SHOWER...WITH A
SIGNIFICANT BREAK OF FAIR WEATHER POSSIBLE BETWEEN THE PRE-FRONTAL
TROF AND THE FRONT ITSELF.
&&
.SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY NIGHT/...
THE CLOSED UPPER LOW OVER ONTARIO PROVINCE BETWEEN THE NORTHERN
GREAT LAKES AND JAMES BAY WILL MOVE EAST SUNDAY NIGHT AS A
POSTFRONTAL SURFACE RIDGE BUILDS ACROSS NEW YORK STATE. THIS WILL
CLEAR OUT LOW LEVEL DEWPOINTS FROM THE UPPER 50S TO 60 DEGREES
SUNDAY EVENING...TO THE MID 40S TO LOW 50S BY DAYBREAK ON MONDAY.
THERE WILL ALSO BE A CLEARING TREND WITH THE INFLUX OF THE DRIER
AIRMASS AND COLD ADVECTION WILL BRING OVERNIGHT LOWS TO THE UPPER
40S TO LOW 50S.
SURFACE HIGH PRESSURE CENTER OVER SOUTHERN ONTARIO PROVINCE WILL
PROVIDE A DRY AND COOL PERIOD FOR THE FIRST HALF OF THE WEEK WITH
POPS NEAR ZERO AND ABUNDANT SUNSHINE. HIGH TEMPS WILL BE IN THE
LOWER TO MIDDLE 60S AT THE START OF THE WEEK AND NUDGE UP TO THE MID
AND UPPER 60S ON TUESDAY. DRY AIR AND CLEAR SKIES AT NIGHT WILL
ALLOW LOW TEMPS TO FALL TO THE LOWER TO MID 40S FOR MOST OF THE AREA
MONDAY NIGHT AND MOSTLY IN THE MID TO UPPER 40S FOR TUESDAY NIGHT.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
THE CENTER OF THE SURFACE HIGH ACROSS SOUTHERN ONTARIO WILL MOVE
EASTWARD AND ALLOW A SOUTHERLY FLOW ACROSS THE FORECAST AREA. THIS
WILL BRING A MIDWEEK WARMING TREND WITH HIGH TEMPS RETURNING TO NEAR
NORMAL READINGS IN THE LOWER TO MID 70S. OVERNIGHT LOWS WILL ALSO
MODERATE TO NEAR OR ABOVE NORMAL READINGS...RANGING FROM THE LOWER
TO MID 50S WEDNESDAY NIGHT TO THE MID AND UPPER 50S THURSDAY NIGHT
AND FRIDAY NIGHT.
THE RETURN OF WARMTH WILL ALSO BRING A RETURN OF HUMIDITY AND A FAIR
CHANCE OF RAIN FROM THURSDAY THROUGH SATURDAY. PRECIPITABLE WATER
VALUES WILL INCREASE FROM AROUND A HALF INCH AT MID WEEK TO MORE
THEN AN INCH AND A HALF BY THE END OF THE WEEK...THUS WE CAN EXPECT
THE POSSIBILITY OF DOWNPOURS ASSOCIATED WITH ANY CONVECTION.
&&
.AVIATION /21Z SATURDAY THROUGH THURSDAY/...
OUTSIDE OF SCATTERED SHOWERS AND THUNDERSTORMS...EXPECT MAINLY VFR
CONDITIONS FOR THE REMAINDER OF THE AFTERNOON. THIS RISK WILL BE
GREATEST LATE AFTERNOON...THEN BRIEFLY DIMINISH THIS EVENING
BEFORE INCREASING AGAIN LATER THIS EVENING. THESE WILL PROBABLY
BRING PERIODS OF MVFR CONDITIONS OR LOWER IN HEAVY RAIN. SHOWERS
AND THUNDERSTORMS SHOULD TAPER OFF FROM WEST TO EAST ON SUNDAY
MORNING.
OUTLOOK...
SUNDAY...VFR MUCH OF THE TIME...BUT OCCASIONAL SHOWERS AND
THUNDERSTORMS WILL PRODUCE LOCAL MVFR/IFR AT TIMES.
MONDAY-WEDNESDAY...VFR.
&&
.MARINE...
GUSTY SOUTHWEST WINDS HAVE PROMPTED SMALL CRAFT ADVISORIES ON
WESTERN LAKE ONTARIO AND THE LOWER NIAGARA RIVER FOR THE REMAINDER
OF THIS AFTERNOON. THESE SHOULD SUBSIDE TOWARD SUNSET. THESE ARE
MAINLY DUE TO DAYTIME MIXING...WITH WINDS LIKELY TO BE LESS
FURTHER OFFSHORE.
OTHERWISE...AN AREA OF LOW PRESSURE WILL PASS BY TO THE NORTH OF THE REGION
SUNDAY WITH A COLD FRONT CROSSING THE LOWER LAKES. WINDS WILL
INCREASE OUT OF THE SOUTHWEST ALONG AND BEHIND THIS COLD FRONT WITH
THE POTENTIAL FOR A PERIOD OF WINDS AND WAVES APPROACHING SMALL
CRAFT ADVISORY CRITERIA.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR LOZ030-
042.
&&
$$
SYNOPSIS...APFFEL
NEAR TERM...APFFEL
SHORT TERM...WCH
LONG TERM...WCH
AVIATION...APFFEL
MARINE...APFFEL/WCH
AREA FORECAST DISCUSSION
NWS BUFFALO NY
348 PM EDT SAT JUN 1 2013
.SYNOPSIS...
A COLD FRONT WILL GRADUALLY APPROACH FROM THE UPPER LAKES
TONIGHT...CROSSING THE REGION LATE ON SUNDAY. THIS WILL BRING AN
INCREASING CHANCE FOR SHOWERS AND THUNDERSTORMS TONIGHT INTO
SUNDAY...WITH LOCALLY HEAVY DOWNPOURS POSSIBLE. COOLER AND DRIER AIR
WILL BUILD INTO THE REGION FOR THE FIRST HALF OF THE WEEK.
&&
.NEAR TERM /THROUGH SUNDAY/...
FOR THE REMAINDER OF THIS AFTERNOON...WESTERN NEW YORK SHOULD REMAIN
IN A BREEZY SOUTHWESTERLY FLOW. THE BIG QUESTION IS TO WHAT EXTENT
SHOWERS AND THUNDERSTORMS WILL DEVELOP. THE MAIN AREA TO WATCH IS
WAVE OF MOISTURE UPSTREAM ACROSS EAST-CENTRAL LAKE ERIE AND SOUTHERN
ONTARIO. THROUGH 330 PM...SHOWERS AND A FEW THUNDERSTORMS HAVE
DEVELOPED WITH THIS FEATURE. WHILE THIS WILL CONTINUE TO MOVE TO THE
EAST...EXPECT THAT THE BRISK SSW FLOW WILL MIX AND DOWNSLOPE ON THE
NIAGARA FRONTIER...WHICH WILL DIMINISH THE CHANCE FOR THUNDERSTORMS
FOR THE TIME BEING. HOWEVER...AS IT MOVES FURTHER EAST...IT MAY BE
ABLE TO TAKE ADVANTAGE OF INSTABILITY ACROSS INTERIOR PORTIONS OF
THE SOUTHERN TIER. OTHERWISE...THERE STILL REMAINS A CHANCE A FEW
STORMS WILL DEVELOP SOUTHEAST OF LAKE ONTARIO. DESPITE THE SHORT
TIMEFRAME...MODEL GUIDANCE HAS STRUGGLED SIGNIFICANTLY GIVEN THE
SUBTLE NATURE RESPONSIBLE FOR THIS CONVECTION...WITH FORECAST
PRIMARILY BASED ON RADAR TRENDS AND CURRENT OBS...WITH MODEL
CONSENSUS PROVIDING LIMITED INFORMATION.
FORECAST CONFIDENCE INCREASES LATER TONIGHT...DUE TO A STRONGER
MODEL CONSENSUS. WITH THE HRRR LENDING SUPPORT THE OTHER GUIDANCE
(NAM/RGEM/SREF/GFS)...THERE IS A HIGH CONFIDENCE IN SHOWERS AND
THUNDERSTORMS MOVING IN FROM WEST TO EAST LATE TONIGHT AS AN UPPER
TROF GETS CLOSER. A STRONG MODEL CONSENSUS SHOWS SOME MEASURABLE QPF
IN WESTERN SECTIONS BY DAYBREAK SUNDAY...AND GIVEN THE SYNOPTIC
FEATURE THIS MAKES SENSE.
FORECAST WIND PROFILES SHOW 850 MB WINDS INCREASING FROM 35 KTS TO
45 KTS BY DAYBREAK SUNDAY. THIS COMBINED WITH SOME VEERING WITH
HEIGHT WILL RESULT IN MODEST SHEAR...WHICH WILL AID ORGANIZATION OF
ANY THUNDERSTORMS. THE SEVERE POTENTIAL IS BEST EARLY ON...SINCE
WINDS ARE LESS LIKELY TO MIX DOWN THE LATER IN THE EVENING IT GETS.
THIS CONTINUES TO BEAR WATCHING...WITH BOTH GUSTY WINDS AND LARGE
HAIL POSSIBLE IN STRONG THUNDERSTORMS.
ANOTHER CONCERN IS THE POTENTIAL FOR HEAVY RAIN...WITH PWATS
FORECAST TO INCREASE TO 1.75 INCHES BY BOTH THE NAM/GFS.
TEMPERATURES WILL REMAIN ON THE WARM SIDE DURING THE PERIOD. THE
SSW FLOW HAS RESULTED IN MODEST DOWNSLOPING...WHICH CAUSED
TEMPERATURES TO RISE INTO THE MID AND UPPER 80S NORTH OF I-90.
TEMPERATURES SHOULD ONLY DROP INTO THE UPPER 60S IN MOST LOCATIONS
OVERNIGHT.
SHOWERS AND THUNDERSTORMS SHOULD TAPER OFF FROM WEST TO EAST ON
SUNDAY. THIS ACTIVITY IS LIKELY TO BE ALONG A PRE-FRONTAL
TROF...WITH THE ACTUAL FRONT AND WIND SHIFT LIKELY TO HOLD OFF UNTIL
LATER IN THE DAY. THIS MAY SPARK AN ADDITIONAL SHOWER...WITH A
SIGNIFICANT BREAK OF FAIR WEATHER POSSIBLE BETWEEN THE PRE-FRONTAL
TROF AND THE FRONT ITSELF.
&&
.SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY NIGHT/...
THE CLOSED UPPER LOW OVER ONTARIO PROVINCE BETWEEN THE NORTHERN
GREAT LAKES AND JAMES BAY WILL MOVE EAST SUNDAY NIGHT AS A
POSTFRONTAL SURFACE RIDGE BUILDS ACROSS NEW YORK STATE. THIS WILL
CLEAR OUT LOW LEVEL DEWPOINTS FROM THE UPPER 50S TO 60 DEGREES
SUNDAY EVENING...TO THE MID 40S TO LOW 50S BY DAYBREAK ON MONDAY.
THERE WILL ALSO BE A CLEARING TREND WITH THE INFLUX OF THE DRIER
AIRMASS AND COLD ADVECTION WILL BRING OVERNIGHT LOWS TO THE UPPER
40S TO LOW 50S.
SURFACE HIGH PRESSURE CENTER OVER SOUTHERN ONTARIO PROVINCE WILL
PROVIDE A DRY AND COOL PERIOD FOR THE FIRST HALF OF THE WEEK WITH
POPS NEAR ZERO AND ABUNDANT SUNSHINE. HIGH TEMPS WILL BE IN THE
LOWER TO MIDDLE 60S AT THE START OF THE WEEK AND NUDGE UP TO THE MID
AND UPPER 60S ON TUESDAY. DRY AIR AND CLEAR SKIES AT NIGHT WILL
ALLOW LOW TEMPS TO FALL TO THE LOWER TO MID 40S FOR MOST OF THE AREA
MONDAY NIGHT AND MOSTLY IN THE MID TO UPPER 40S FOR TUESDAY NIGHT.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
THE CENTER OF THE SURFACE HIGH ACROSS SOUTHERN ONTARIO WILL MOVE
EASTWARD AND ALLOW A SOUTHERLY FLOW ACROSS THE FORECAST AREA. THIS
WILL BRING A MIDWEEK WARMING TREND WITH HIGH TEMPS RETURNING TO NEAR
NORMAL READINGS IN THE LOWER TO MID 70S. OVERNIGHT LOWS WILL ALSO
MODERATE TO NEAR OR ABOVE NORMAL READINGS...RANGING FROM THE LOWER
TO MID 50S WEDNESDAY NIGHT TO THE MID AND UPPER 50S THURSDAY NIGHT
AND FRIDAY NIGHT.
THE RETURN OF WARMTH WILL ALSO BRING A RETURN OF HUMIDITY AND A FAIR
CHANCE OF RAIN FROM THURSDAY THROUGH SATURDAY. PRECIPITABLE WATER
VALUES WILL INCREASE FROM AROUND A HALF INCH AT MID WEEK TO MORE
THEN AN INCH AND A HALF BY THE END OF THE WEEK...THUS WE CAN EXPECT
THE POSSIBILITY OF DOWNPOURS ASSOCIATED WITH ANY CONVECTION.
&&
.AVIATION /20Z SATURDAY THROUGH THURSDAY/...
OUTSIDE OF SCATTERED SHOWERS AND THUNDERSTORMS...EXPECT MAINLY VFR
CONDITIONS FOR THE REMAINDER OF THE AFTERNOON. FOR THE MOST
PART...ANY STORMS ARE LIKELY TO MISS MOST TAF LOCATIONS. CHANGES
FOR THUNDERSTORMS WILL INCREASE THIS EVENING...AS A LINE OF
STEADIER SHOWERS AND THUNDERSTORMS ARE LIKELY TO MOVE IN. THESE
WILL PROBABLY BRING PERIODS OF MVFR CONDITIONS OR LOWER IN HEAVY
RAIN. SHOWERS AND THUNDERSTORMS SHOULD TAPER OFF FROM WEST TO EAST
ON SUNDAY MORNING.
OUTLOOK...
SUNDAY...VFR MUCH OF THE TIME...BUT OCCASIONAL SHOWERS AND
THUNDERSTORMS WILL PRODUCE LOCAL MVFR/IFR AT TIMES.
MONDAY-WEDNESDAY...VFR.
&&
.MARINE...
GUSTY SOUTHWEST WINDS HAVE PROMPTED SMALL CRAFT ADVISORIES ON
WESTERN LAKE ONTARIO AND THE LOWER NIAGARA RIVER FOR THE REMAINDER
OF THIS AFTERNOON. THESE SHOULD SUBSIDE TOWARD SUNSET. THESE ARE
MAINLY DUE TO DAYTIME MIXING...WITH WINDS LIKELY TO BE LESS
FURTHER OFFSHORE.
OTHERWISE...AN AREA OF LOW PRESSURE WILL PASS BY TO THE NORTH OF THE REGION
SUNDAY WITH A COLD FRONT CROSSING THE LOWER LAKES. WINDS WILL
INCREASE OUT OF THE SOUTHWEST ALONG AND BEHIND THIS COLD FRONT WITH
THE POTENTIAL FOR A PERIOD OF WINDS AND WAVES APPROACHING SMALL
CRAFT ADVISORY CRITERIA.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR LOZ030-
042.
&&
$$
SYNOPSIS...APFFEL
NEAR TERM...APFFEL
SHORT TERM...WCH
LONG TERM...WCH
AVIATION...APFFEL
MARINE...APFFEL/HITCHCOCK
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
114 PM EDT SAT JUN 1 2013
.SYNOPSIS...
BERMUDA HIGH PRESSURE WILL HOLD OVER THE OFFSHORE WATERS THROUGH
THE WEEKEND. THE BEST CHANCE OF RAIN WILL ARRIVE MONDAY INTO
TUESDAY...AS A COLD FRONT DROPS SOUTHEAST ACROSS THE REGION. HIGH
PRESSURE WILL BUILD SOUTH ACROSS THE AREA THROUGH THE MIDDLE OF
NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 114 PM SATURDAY...AN EARLY SUMMER PATTERN APPEARS WELL IN
PLACE FOR TODAYS FORECAST...THOUGH A BIT DRY ALOFT PER 12Z RAOB
PLOTS FROM CHS/MHX. ISOLATED SHOWERS/TSTMS WILL BE RETAINED FOR
THIS AFTERNOON AS THE INLAND ADVANCING SEA BREEZE FRONT PLOWS TO
THE NW INTO A HUMID LOW-LEVEL AIR MASS WITH SURFACE DEWPOINTS
AROUND 70 DEG F ACROSS MUCH OF THE FORECAST AREA. THE SEA BREEZE
WILL BE THE ONLY IMPETUS FOR CONVECTIVE GENERATION AND SUBSEQUENT
LOWER TROPOSPHERIC OMEGA IN A NARROW BAND MARCHING INLAND THROUGH
THE AFTERNOON HOURS. POPS ARE SHAPED TO DROP BELOW MENTIONABLE
VALUES BY 22Z/6PM PER LATEST 4KM NSSL WRF AND HRRR 3KM DEPICTIONS.
MAXIMUM TEMPERATURES TODAY LOW TO MIDDLE 80S COAST AND COASTAL
INTERIOR TO THE UPPER 80S WELL INLAND REMOVED FROM THE COOLING
AND INLAND PROGRESSING MARINE LAYER. A QUIET AND FAIR EVENING AND
OVERNIGHT PERIOD ANTICIPATED...WITH MIDDLE AND UPPER 60S FOR LOW
TEMPS BY DAYBREAK SUNDAY WITH A LIGHT SOUTH WIND EXPECTED TONIGHT.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 3 AM SATURDAY...MID LEVEL DRY AIR AND WEAK SUBSIDENCE WILL
WORK TO KEEP THE REGION DRY SUN. DO THINK THERE WILL BE SOME
ISOLATED CONVECTION DEVELOPING ON THE SEABREEZE BUT BEST CHANCE FOR
PRECIP WILL BE LATER SUN ACROSS INLAND SC. INCREASING DEEP MOISTURE
AHEAD OF THE SLOWLY ADVANCING COLD FRONT AND WEAKENING SUBSIDENCE AS
RIDGING RETREATS LEADS TO DEVELOPMENT OF LATE AFTERNOON SHOWERS AND
THUNDERSTORMS. INHERITED SLIGHT CHANCE TO CHANCE POP IS REASONABLE
BUT HAVE EXPANDED CHC POP AREA A BIT FARTHER EAST.
SECOND HALF OF THE PERIOD APPEARS QUITE WET WITH SHOWERS AND
THUNDERSTORMS A GOOD BET. DEEP MOIST SOUTHWEST FLOW WILL PUMP PLENTY
OF GULF MOISTURE INTO THE REGION AHEAD OF THE COLD FRONT.
PRECIPITABLE WATER VALUES APPROACH 2 INCHES MON AFTERNOON AND
EVENING IN CONJUNCTION WITH SOME WEAK DIVERGENCE ALOFT. MID LEVEL
LAPSE RATES ARE ON THE WEAK SIDE BUT CONVERGENCE AHEAD OF AND ALONG
THE FRONT SHOULD BE ABLE TO TAP INTO WHAT MID LEVEL INSTABILITY IS
PRESENT. ENVIRONMENT IS NOT SUPPORTIVE OF ANY SIGNIFICANT SEVERE
THREAT MON/MON NIGHT BUT DEEP MOISTURE...SLOW STORM MOTION...AND
DEEP WARM CLOUD LAYER SUGGEST STORMS THAT DO DEVELOP WILL HAVE
POTENTIAL TO DROP A LOT OF RAIN.
HIGH TEMPERATURES WILL BE NEAR TO SLIGHTLY BELOW CLIMO. TEMPERATURES
WILL BE WARMEST SUN WITH INCREASING MOISTURE AND EARLIER CLOUD
DEVELOPMENT LIMITING HIGHS ON MON. LOWS WILL REMAIN ABOVE CLIMO BOTH
NIGHT...HELD UP BY DEBRIS CLOUD AND LOW LEVEL MOISTURE.
&&
.LONG TERM /TUESDAY THROUGH SATURDAY/...
AS OF 3 AM SATURDAY...SLOW MOVING COLD FRONT WILL BE IN THE AREA AT
THE START OF THE PERIOD. LIMITED MID LEVEL PUSH KEEPS THE FRONT
ALONG THE COAST FOR AT LEAST FIRST PART OF TUE SO PRECIP MAY LINGER
INTO AFTERNOON. INHERITED CHC POP SEEMS REASONABLE AND WILL BE
MAINTAINED.
MIDDLE TO END OF THE WEEK REMAINS IN QUESTION AS POTENTIAL
DEVELOPMENT OF TROPICAL OR SUBTROPICAL SYSTEM IN THE GULF OF MEXICO
AND ITS MOISTURE PLUME CLOUDS THE FUTURE. ILL DEFINED MID LEVEL
PATTERN AND HIGH PRESSURE BUILDING IN FROM THE NORTH LEADS TO A WEAK
WEDGE TYPE SET UP. ANTICIPATE A SCATTERED TO BROKEN FLAT STRATOCU
DECK WITH LIMITED POTENTIAL FOR PRECIP WED/THU GIVEN VERY LITTLE
FORCING AND DEEP DRY AIR ALOFT. BEST CHANCE WOULD BE ALONG THE COAST
AS SHOWERS OVER THE WATERS MOVE ONSHORE. NORTHEAST TO EAST FLOW WILL
KEEP HIGHS SLIGHTLY BELOW CLIMO WHILE HOLDING LOWS NEAR TO SLIGHTLY
ABOVE.
LARGE DEGREE OF UNCERTAINTY LATE WITH RESPECT TO SYSTEM EMERGING
FROM GULF OF MEXICO. GFS/ECMWF/CANADIAN ALL SHOW THE FEATURE BUT
WITH WILDLY DIFFERENT SOLUTIONS. 00Z CANADIAN LOOKS NOTHING LIKE ITS
12Z RUN AND IS BEING DISCOUNTED FOR NOW. LATEST GFS SOLUTION KEEPS
THE LOW WELL OFF THE SOUTHEAST COAST AS IT MOVES NORTHEAST ALONG
REMAINS OF WASHED OUT COLD FRONT. LACK OF SIGNIFICANT STEERING LEVEL
FEATURES AND A FAIRLY WEAK SURFACE PATTERN SUPPORT A SLOWER
SOLUTION...RULING OUT THE LATEST CANADIAN. GIVEN THE LACK OF
STEERING FEATURES THINK THE LOW IS GOING TO TRAVEL NORTHEAST ALONG
THE REMAINS OF THE TROUGH...SIMILAR TO WHAT THE LATEST GFS IS
SUGGESTING. FOR NOW WILL TREND FORECAST IN THAT DIRECTION...THOUGH
THE 12Z ECMWF SOLUTION...WHICH IS SLOWER/DEEPER AND MOVES THE
SYSTEM INTO THE SOUTHEAST...CANNOT NOT BE TOTALLY DISCOUNTED.
HIGHS ARE LIKELY TO END UP BELOW CLIMO LATE NEXT WEEK WITH LOWS
RUNNING A LITTLE ABOVE CLIMO.
&&
.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
AS OF 17Z...TERMINALS ARE VFR AND THERE IS HIGH CONFIDENCE VFR
WILL CONTINUE INTO THE EVENING HOURS. WINDS WILL BE SE-S WITH
HIGHEST SPEEDS AT THE COAST. ISOLATED SHOWERS WILL POSSIBLY
DEVELOP JUST INLAND OF THE COASTAL TERMINALS THIS AFTERNOON AS THE
SEA BREEZE PROGRESSES INLAND. MODELS ARE NOT INDICATING ANY
SIGNIFICANT LIFT NOR COVERAGE SO WILL NOT MENTION ANY
PRECIPITATION AT ANY TERMINALS EVEN THOUGH THE SEA BREEZE WILL BE
MOVING JUST TO THE EAST OF THE KFLO/KLBT TERMINALS LATER THIS
AFTERNOON. WITH LITTLE CHANGE IN THE OVERALL PATTERN/AIRMASS WILL
CONTINUE TO INDICATE ANOTHER ROUND OF FOG/STRATUS AFTER MIDNIGHT
WITH WORST CONDITIONS AT KFLO/KLBT. IMPROVEMENT TO VFR EXPECTED
13-14Z WITH SE-S WINDS DEVELOPING BY MID MORNING.
EXTENDED OUTLOOK...EARLY MORNING MVFR/IFR CIGS/VSBYS POSSIBLE EARLY
SUNDAY AND MONDAY. INCREASING MVFR/IFR PRODUCING CONVECTION CHANCES
AND COVERAGE MONDAY AND TUESDAY...DROPPING BACK TO ISOLATED
WEDNESDAY AND THURSDAY.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 114 PM SATURDAY...NO MARINE HAZARDS ANTICIPATED TODAY OR
TONIGHT ASIDE FROM INCREASED WEEKEND BOATING TRAFFIC ON THE
WATERS. BERMUDA HIGH PRESSURE AND THE SEA BREEZE CIRCULATION WILL
INDUCE S-SE WINDS TODAY...INCREASING A BIT IN THE AFTERNOON TO
AROUND 15 KT FROM INLAND HEATING AND CONSERVATION OF MASS LAWS.
THE SEA SPECTRUM WILL BE COMPRISED OF SE WAVES AROUND 3 FEET AT 8
SECONDS AND A SLIGHT SOUTHERLY CHOP...BECOMING MODERATE NEAR SHORE
IN THE AFTERNOON TO EARLY EVENING. NO TSTMS OR RESTRICTIONS TO
VISIBILITY EXPECTED TODAY OR TONIGHT.
SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 3 AM SATURDAY...SOUTHERLY FLOW BELOW 10 KT AT THE START OF THE
PERIOD INCREASES TO 10 TO 15 KT SUN AFTERNOON...REMAINING SOUTHERLY
AND IN THE 10 TO 15 KT RANGE THROUGH THE END OF THE PERIOD. BERMUDA
HIGH RETREATS SUN NIGHT AND MON AS COLD FRONT APPROACHES FROM THE
WEST. OVERALL LITTLE CHANGE TO PRESSURE GRADIENT ANTICIPATED WHICH
WILL KEEP SPEEDS IN THE 10 TO 15 KT RANGE THROUGH MON NIGHT. SEAS
WILL RUN 3 TO 4 FT FOR MUCH OF THE PERIOD.
LONG TERM /TUESDAY THROUGH WEDNESDAY/...
AS OF 3 AM SATURDAY...COLD FRONT STALLING IN THE AREA TUE WILL LEAD
TO LIGHT AND VARIABLE WINDS...EVENTUALLY BECOMING NORTHERLY BY TUE
EVENING. GRADIENT REMAINS WEAK TUE NIGHT WITH SPEEDS 10 KT OR LESS.
NORTHEAST FLOW BECOMES MORE ESTABLISHED WED AS HIGH PRESSURE NOSES
DOWN THE COAST. PINCHED GRADIENT RESULTS IN NORTHEAST FLOW
INCREASING TO 15 TO 20 KT WED AND WED NIGHT. SEAS AROUND 3 FT TO
START THE PERIOD WILL BUILD TO 3 TO 5 FT WED AND WED NIGHT.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...MJC
SHORT TERM...III
LONG TERM...III
AVIATION...MRR/MJC
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
1245 PM CDT SAT JUN 1 2013
.UPDATE...
ISSUED AT 950 AM CDT SAT JUN 1 2013
LOW CU DEVELOPING BEHIND MAIN CLOUD BAND WITH LOW CONVECTIVE
TEMPERATURE VALUES. RAP GUIDANCE SUGGESTS THIS WILL CONTINUE
THROUGH THE AFTERNOON. WILL DELAY CLEARING AND LOWER MAX TEMPS A
FEW DEGREES. NO OTHER UPDATES NEEDED.
&&
.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 410 AM CDT SAT JUN 1 2013
MODELS ARE IN GOOD AGREEMENT OVERALL...AND PREFER THE CONSISTENT GFS.
FOR TODAY...EXPECT SKIES TO CLEAR FROM NORTH TO SOUTH. IT WILL BE
WINDY WITH GUSTS TO AROUND 35MPH AT TIMES. IT WILL BE BORDERLINE
WIND ADVISORY CRITERIA...BUT EXPECT IT TO REMAIN JUST BELOW
ADVISORY LEVELS. TEMPS WILL BE COOL FOR THIS TIME OF YEAR...AND
MOST AREAS WILL NOT REACH 60.
FOR TONIGHT...IT WILL BE COLD WITH TEMPS BELOW NORMAL. CAN/T RULE
OUT SOME FOG GIVEN WET CONDITIONS...BUT FOR NOW WILL NOT MENTION
BUT MONITOR.
ON SUNDAY...EXPECT PLENTIFUL SUNSHINE WITH HIGH PRESSURE OVERHEAD.
TEMPS WILL STILL REMAIN BELOW NORMAL BUT IT WILL BE WARMER THAN
TODAY.
.LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY)
ISSUED AT 410 AM CDT SAT JUN 1 2013
FOR SUNDAY NIGHT...ANOTHER COOL NIGHT IS EXPECTED BUT NOT QUITE AS
COLD AS TONIGHTS TEMPS.
ON MONDAY...THE CHANCES FOR SHOWERS WILL INCREASE IN THE WEST BY
AFTERNOON...AS THE NEXT SLOW MOVING STORM SYSTEM APPROACHES.
TEMPS COULD BE WARMER IF MORE SUNSHINE OCCURS...ESPECIALLY IN THE
NORTHEAST WHERE IT COULD TURN OUT TO BE MOSTLY SUNNY.
FOR TUESDAY THROUGH FRIDAY...SPLIT FLOW IS EXPECTED ACROSS CANADA
AND THE US. LONG WAVE TROUGH OVER THE NORTHERN PLAINS SHIFTS
SLIGHTLY EAST THROUGH THE PERIOD. LONG WAVE RIDGE OVER SOUTHERN
CANADA SHIFTS EAST AND FLATTENS BY THE END OF THE PERIOD.
GFS WAS TRENDING SLOWER FROM MODEL RUN TO MODEL RUN WHILE THE ECMWF
WAS TRENDING FASTER. WILL PREFER A BLEND OF THE TWO MODELS. SO
TODAYS PRECIPITATION WAS SLIGHTLY FASTER THAN YESTERDAYS RUN.
LITTLE CHANGE TO TEMPS FROM YESTERDAYS PACKAGE. HIGH TEMPS HAVE BEEN
LOWERED A DEGREE OR TWO FOR TUE AND WED AND A DEGREE OR TWO HIGHER
FOR THU AND FRI.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1245 PM CDT SAT JUN 1 2013
THE MAIN AVIATION CHALLENGE WILL BE CLOUD TRENDS THIS AFTERNOON.
THE EXTENSIVE MVFR CLOUD SHIELD BEHIND THE DEPARTING LOW PRESSURE
SYSTEM HAS BEEN SLOW TO SHIFT SOUTHEASTWARD...WITH A FEW LINGERING
SHOWERS TOWARDS KBJI. IN ADDITION...DIURNAL CU HAVE DEVELOPED ON
THE BACK EDGE OF THE CLOUD SHIELD TOWARDS THE DVL AREA. STILL
EXPECT GRADUAL CLEARING LATE THIS AFTERNOON AND THIS EVENING AS
THE SFC HIGH APPROACHES. THE TIMING OF THE CLEARING WILL NEED TO
BE MONITORED. NORTH WINDS WILL REMAIN GUSTY THROUGH LATE
AFTERNOON...AND THEN QUICKLY BEGIN TO SUBSIDE DURING THE EARLY
EVENING.
&&
.HYDROLOGY...
ISSUED AT 1245 PM CDT SAT JUN 1 2013
RIVERS CONTINUE TO RESPOND ABOUT AS FORECAST FROM RECENT RAINS.
STILL RECEIVING LATE REPORTS FROM AREA EM`S. ONE SUCH REPORT FROM
WALSH COUNTY EM WAS OF 7 INCHES YESTERDAY IN THE OAKWOOD AREA NEAR
THE TORNADIC CELL. AS RUNOFF MAXIMIZES TODAY EXPECT PEAKS TO OCCUR
IN THE NEXT 12 TO 36 HOURS.
GRAFTON ON ITS WAY TO MAJOR FLOOD LEVELS. DEPENDING ON THE TIMING OF
LOCAL UPSTREAM CONTRIBUTION THE CREST COULD EXCEED 14.5 FEET.
THEREFORE HAVE ADDED A 14.0 TO 15.0 RANGE IN FLS. MINTO RISING AND
IS ON TRACK TO REACH 7.0 FEET FORECAST FOR JUNE 3RD.
NECHE HAS EXCEEDED MAJOR FLOOD LEVEL AS OF 17Z AND IS ON THE WAY TO
21.0 FEET. CURRENT RATE OF RISE SUGGESTS IT MAY EXCEED THAT AND WILL
COORDINATE WITH THE RFC. THE TWO RIVERS AT HALLOCK IS LAYING OVER
AND WILL CREST JUST BELOW MODERATE FLOOD LEVELS.
HAVE EXTENDED THE AREAL FLOOD WARNING FOR EASTERN WALSH COUNTY DUE
TO CONTINUED ROAD CLOSURES. OVERLAND FLOODING CONTINUES EAST OF THE
ESCARPMENT ON THE RED RIVER VALLEY FLOOD AS DRAINAGE RETARDED DUE TO
HIGH RIVER LEVELS.
OTHERWISE HIGH WATER STATEMENTS IN EFFECT AT WAHPETON...OSLO...
DRAYTON AND PEMBINA. THE FLOOD WARNING HAS BEEN CANCELLED FOR
WALHALLA AND REPLACED WITH AN RVS.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...TG
SHORT TERM...DK
LONG TERM...HOPPES/DK
AVIATION...MAKOWSKI
HYDROLOGY...EWENS
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
541 PM EDT SAT JUN 1 2013
.SYNOPSIS...
WEATHER SYSTEM OVER THE WESTERN GREAT LAKES WILL SHIFT EASTWARD
TONIGHT...DRAGGING A COLD FRONT THROUGH THE OHIO VALLEY LATER
TONIGHT AND SUNDAY. THIS WILL PROMPT SEVERAL ROUNDS OF SHOWERS AND
STORMS FOR THE AREA...BEFORE A DRYING TREND TAKES HOLD FOR SUNDAY
NIGHT...LASTING INTO THE MIDDLE OF NEXT WEEK. A COOLER AND DRIER
AIRMASS WILL DOMINATE THROUGH THIS TIME PERIOD.
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
...QUICK UPDATE...
OF MOST IMMINENT CONCERN FOR SVR WX IS NRN END OF LARGER SCALE
LINE OF STORMS TAKING SHAPE FROM EAST OF FRANKFORT ALL THE WAY
INTO CNTL TN. THERE ARE FEW DISCRETE UPDRAFTS THAT HAVE BEEN
BROADLY/WEAKLY ROTATING ABOUVE 5KFT AS THEY MOVE NORTHEAST TOWARD OUR
NERN KY COUNTIES. MESOA SUPPORTS THIS - WITH DEEP SHEAR AROUND 35
KTS - MARGINAL BUT SUFFICIENT FOR SOME ROTATING UPDRAFTS. THESE
MAY POSE A BRIEF HAIL/WIND/TORNADO THREAT INTO OUR SERN AREAS OVER
THE NEXT TWO HOURS. THE TOR THREAT STILL IS QUITE MARGINAL WITH
KILN VWP BEING VERY DEEP UNIDIRECTIONAL FLOW OUT OF THE SW AND
THUS 0-1KM SHEAR MOSTLY < 20 KTS. BUT WILL CLOSELY WATCH THESE
CELLS. OTHERWISE REST OF THINKING STILL IS ON TRACK...WITH MUCH
UNCERTAINTY HOW STORMS NOW DEVELOPING IN ILLINOIS ALONG THE COLD
FRONT WILL MAINTAIN THROUGH LARGE INSTBY MINIMUM OVER IND.
...PREVIOUS DISCUSSION BELOW...
FOR BEING AS CLOSE AS WE ARE TO GETTING INTO A POTENTIAL SEVERE
WEATHER EVENT...UNCERTAINTY REMAINS VERY HIGH GIVEN HOW EXTENSIVE
FRIDAY CONVECTIVE COMPLEXES HAVE MODULATED THE AVAILABLE
INSTABILITY AND SHIFTED WEAK FOCI FOR CONVECTIVE INITIATION RATHER
SUBSTANTIALLY. AMALGAM OF CONVECTION ALLOWING MODELS /CAMS/
RUNNING EXPERIMENTALLY AT 3-4KM RESOLUTION HAVE BEEN WILD AND
ERRATIC IN THEIR SOLUTIONS FROM RUN TO RUN WITH CONVECTIVE
COVERAGE/INTENSITY WHETHER IT BE HRRR OR NCEP VERSIONS OF HIRESW-
NMM/ARW WINDOWS. THUS - UNCERTAINTY IS HIGH AND DO NOT HAVE GOOD
FEELING HOW NEXT 12 HOURS WILL EVOLVE.
18Z MESOANALYSIS /SUBJECTIVE AND OBJECTIVE/ SHOWS ERN EDGE OF
DECAYED MCS FROM LAST NIGHT NOW FROM AREAS AROUND CVG SOUTHWEST TO
NEAR BOWLING GREEN KENTUCKY. EAST OF THIS DEMARCATION - MAINLY
ALONG AND EAST OF I-71 IN KY/OHIO AS OF RIGHT NOW - THE
ATMOSPHERE IS SUPPORTIVE OF AT LEAST STRONG TO MARGINALLY SEVERE
STORMS WITH 0-6KM BULK SHEAR FROM 30 TO 40 KTS...AND MLCAPE FROM
750 TO 1250 J/KG BASED ON THE LOCAL OBSERVATIONS INTEGRATED INTO
LAPS ANALYSIS. WEST OF THIS AREA...IT HAS BEEN SLOWER TO RECOVER
DUE TO DEEPER/STRONGER INFLUENCE FROM RESIDUAL OUTFLOWS/COLD POOLS
FROM THE OVERNIGHT MCS. BUT THIS AREA IS DESTABILIZING MILDLY TOO.
BASED ON A NUMBER OF DIFFERENT CAM RUNS...AND THE MESOA MENTIONED
ABOVE...FEEL THE BEST SHORT TERM THREAT FOR SEVERE WEATHER WILL BE
FROM INCREASING COVERAGE AND INTENSITY OF DISCRETE CELLS NOW OVER
CNTL KY AND UPSCALE GROWTH OF LEADING EDGE OF OLD MCS AREA OVER WRN
KY - WHICH SYNOPTIC SCALE MODELS HAVE BEEN LATCHING ONTO AS A
POSSIBLE AREA OF GROWTH. THIS ALL COULD CONGEAL AND GIVE A
DAMAGING WIND THREAT VIA A CLUSTER OF STORMS IN THE 5 PM TO 9 PM
TIMEFRAME ALONG AND EAST OF A CVG TO CMH LINE. THIS AREA HAS THE
LARGEST DCAPE POOL FOR SEVERE WIND GUST POTENTIAL TO WORK FROM AS
WELL AS MLCAPE...BUT IS DISPLACED EAST A BIT FROM DEEPER SHEAR.
HOWEVER...THERE IS ENOUGH SHEAR IN THE 0-3KM LAYER /30KTS/ THAT A
BOWING SEGMENT OR TWO WOULD BE POSSIBLE. SPC GRABBED A PART OF
THIS AREA IN RECENT SWOMCD WITH MARGINAL CONFIDENCE FOR A
WATCH...SO RADAR TRENDS WILL BE MONITORED UPSTREAM FOR
GROWTH/ORGANIZATION OF STORMS. THE TORNADO THREAT IS NOT TOTALLY
ZERO...LOW LEVEL SHEAR VIA A PERSISTENT SWLY /MOIST/ LLJ IS
KEEPING 0-1KM SHEAR AROUND 20KTS...BUT FLOW IS RATHER
UNIDIRECTIONAL. A LOCAL BACKING TO SLY WOULD MAKE THINGS MORE
INTERESTING BUT THE LARGER SCALE PATTERN DOESN`T REALLY SUPPORT
THAT - SO OVERALL TOR THREAT IS NOT HIGH PER CURRENT
ANALYSIS/FORECASTS. GIVEN MARGINAL INSTBY...HAIL WOULD BE AN
OUTLIER GIVEN THE MOIST ADIABATIC MID LEVEL LAPSE RATES AS WE/VE
BEEN DOWNSTREAM OF THE HIGH MOISTURE CONTENT DECAYING MCS MOST OF
THE DAY.
OVERNIGHT...STRONGER SYNOPTIC SCALE FORCING MOVES ACROSS THE GREAT
LAKES AS DEAMPLIFYING SHORTWAVE TROUGH SLIDES ACROSS THE AREA WITH
ATTENDANT COLD FRONT. EXPECT...AT SOME POINT...A LINE OF SHOWERS
AND STORMS TO BEGIN TO CONGEAL/INCREASE ALONG THIS FEATURE AS WELL
BUT GIVEN ITS EXPECTED ARRIVAL THROUGH THE AREA...EXPECTING SEVERE
THREAT TO REMAIN RATHER MARGINAL WITH THIS. STRONG LOW LEVEL SHEAR
WITH ANY LINE OF SHOWERS/STORMS NEEDS TO BE WATCHED...AND TONIGHT
WILL BE NO EXCEPTION BUT THE LARGE POOL OF MINIMUM INSTABILITY
OVER INDIANA IS GOING TO REALLY WORK AGAINST SOMETHING REALLY
TAKING OFF. WHILE CAM RUNS /AS MENTIONED ABOVE/ ARE REALLY ALL
OVER THE PLACE WITH REGARDS TO RAIN CHANCES TONIGHT...STUCK WITH
STRONGER FORCING /RIGHT ENTRANCE REGION OF JET AND INCREASING PV
AND ATTENDANT LOW LEVEL FRONTAL ZONE/ TO DRIVE HIGHER RAIN/STORM
CHANCES LATE EVENING AND OVERNIGHT...A CONTINUATION OF PREVIOUS
FORECAST. STILL THINK /GIVEN MOIST PWATS ABOVE SEASONAL NORMS/
LOCALLY HEAVY RAIN RATES AND PERHAPS SOME LOCALIZED RUNOFF ISSUES
WILL BE A PROBLEM WITH ANY STORMS THAT LINGER OVER AN AREA MORE
THAN AN HOUR.
&&
.SHORT TERM /6 AM SUNDAY MORNING THROUGH SUNDAY NIGHT/...
SECONDARY WAVE ALOFT FINALLY ESCORTS THE TROUGH AXIS OUT OF THE
AREA TOMORROW AND THIS ALLOWS A WEAK SECONDARY FRONT TO DEVELOP
AND PUSH THROUGH DURING THE DAY. MAY BE A BROKEN BAND OF SHOWERS
ALONG THIS FEATURE BY MID AFTERNOON...SO CARRIED THIS CHANCE FROM
NW-SE ACROSS THE AREA DURING THE LATE MORNING INTO THE EARLY
EVENING. MUCH COOLER/DRIER AIRMASS ARRIVES ON THE HEELS OF THIS
FRONT AND MAKES FOR A COMFORTABLE SUNDAY NIGHT WITH LOWS DOWN INTO
THE 50S UNDER CLEARING SKIES.
&&
.LONG TERM /MONDAY THROUGH SATURDAY/...
PERIOD BEGINS WITH HIGH PRESSURE CENTERED OVER THE UPPER MS VALLEY.
THE HIGH WILL BUILD SE INTO THE LOWER GREAT LAKES THROUGH TUESDAY.
HIGHS ON MONDAY WILL BE COOL...RANGING FROM THE UPPER 60S TO THE
LOWER 70S WHICH WILL BE ABOUT 5 TO 10 DEGREES BELOW NORMAL FOR EARLY
JUNE. TEMPERATURES WILL FALL INTO THE UPPER 40S TO LOWER 50S MONDAY
NIGHT. 12Z MODELS HAVE COME IN A LITTLE WARMER FOR TUESDAY. SO TOOK
A CONSENSUS FORECAST AND RAISED HIGHS FOR TUESDAY INTO THE LOWER TO
MID 70S.
ON WEDNESDAY THE SFC HIGH PRESSURE IS FORECAST TO SLIDE EAST. THE
ECMWF IS THE QUICKEST WITH THE RETURN PCPN...BUT THE REMAINING
MODELS KEEP THE FA DRY...SO LEANED TOWARDS THE MAJORITY.
WEDNESDAY NIGHT INTO THURSDAY AS WRMFNT DEVELOPS OVER THE OH VLY...
ATMOSPHERE BECOMES UNTIL STABLE AND IT LOOKS LIKE THERE WILL BE A
CHANCE OF SCT TSRA. THU NGT INTO FRI...H5 WAVE SWINGS UP THE OH VLY
ADDING EXTRA LIFT AND IT DRIVES A CDFNT ACROSS THE REGION KEEPING
CHC OF CONVECTION IN THE FORECAST. DRIER AIR TRIES TO BUILD IN FOR
SATURDAY.
&&
.AVIATION /22Z SATURDAY THROUGH THURSDAY/...
SOUTHWEST WINDS WILL CONTINUE TO GUST AROUND 20-25 KTS THIS
AFTERNOON. STILL A STUBBORN MID TO HIGH CLOUD DECK OVER MOST OF THE
AREA ALTHOUGH SCT LIGHT SHOWERS ARE COMING TO AN END. WATCHING FOR
POSSIBLE REDEVELOPMENT OF SHOWERS AND THUNDERSTORMS LATER THIS
AFTERNOON. IF THIS MATERIALIZES...AND CONFIDENCE IS NOT
PARTICULARLY HIGH BASED ON LATEST HIGH RESOLUTION MODEL
SOLUTIONS...THINKING THE BEST CHANCE WOULD BE AROUND THE EASTERN
TAF SITES AS THAT AREA HAS SEEN THE MOST DAYTIME HEATING SO FAR.
BETTER CHANCE FOR SHOWERS AND STORMS FOR ALL TAF SITES WILL COME
LATE THIS AFTERNOON AND EVENING AS A COLD FRONT APPROACHES FROM
THE WEST. THIS ACTIVITY WILL SPREAD FROM WEST TO EAST WITH THE
POSSIBILITY OF A FEW STRONG TO SEVERE STORMS CONTAINING BRIEF YET
STRONG SHIFTING WINDS AS THEY PASS. MVFR/IFR CIGS AND VSBYS WILL
BE POSSIBLE WITH ANY STORMS LATE THIS AFTERNOON AND EVENING.
CIGS WILL LIKELY REMAIN MVFR LATE TONIGHT AND SOME LINGERING
SHOWERS WILL BE POSSIBLE AS THE COLD FRONT MOVES ACROSS THE AREA.
EXPECT A GRADUAL RETURN TO VFR CIGS SUNDAY MORNING.
OUTLOOK...NO SIGNIFICANT WEATHER EXPECTED.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...BINAU
NEAR TERM...BINAU
SHORT TERM...BINAU
LONG TERM...SITES
AVIATION...KURZ
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
336 PM EDT SAT JUN 1 2013
.SYNOPSIS...
WARM SECTOR THROUGH TONIGHT WITH CONVECTION POSSIBLE ESPECIALLY
LATE THIS AFTERNOON AND EVENING. COLD FRONT CROSSES SUNDAY INTO
MONDAY. COOLER AND DRIER TO START NEXT WEEK. WARM FRONT THURSDAY.
&&
.NEAR TERM /THROUGH SUNDAY/...
PRIMARY FORECAST CONCERN CONTINUES TO REVOLVE AROUND
SHOWERS/THUNDERSTORM CHANCES AS WELL AS POTENTIAL FOR SEVERE
WEATHER.
REGARDING THUNDERSTORMS THIS AFTERNOON/EVENING...15Z REGIONAL RADAR
IMAGERY AND SFC OBS CONTINUE TO SHOW ONGOING WIDESPREAD
PRECIP...MAINLY IN THE FORM OF SHOWERS...FROM WESTERN OHIO SW-WARD
DOWN THE EXTENT OF THE OHIO RIVER INTO WESTERN TENN/ARKANSAS
RESULTANT OF STRONG OVERNIGHT CONVECTION. SFC TEMPS IN WHAT APPEARED
YESTERDAY TO BE THE FAVORED AREAS OF THUNDERSTORMS AND SUBSEQUENT
SVR WX INITIATION STILL ONLY IN THE MID/UPPER 60S GENERALLY...WITH
NO LIGHTNING STRIKES CURRENTLY. SHOULD PRECIP/CLOUDS HANG ON OVER
THAT AREA...STRONGER STORMS MAY WAIT TO FORM FURTHER EAST OVER
CENTRAL OHIO AND POINTS SOUTHWEST WHERE SFC TEMPS HAVE WARMED TO THE
UPPER 70S/LOW 80S DESPITE FAIRLY DENSE HIGH CLOUD COVER. GOOD
DYNAMICS ARRIVE BY 21Z WHICH CONTINUE INTO THE
EVENING...PARTICULARLY OVER THE WESTERN ZONES WHERE 30-40KTS OF
SHEAR IN PLACE. WITH THE FRONT STILL WELL TO THE WEST
HOWEVER...TOUGH CALL ON DETERMINING A TRIGGERING MECHANISM. A VORT
MAX PER LATEST RUC13 PROGGED TO PUSH NE-WARD THROUGH CENTRAL KY BY
21Z-00Z MAY BE ENOUGH TO GET THINGS GOING. DO FEEL THAT
THUNDERSTORMS WILL SLOWLY BEGIN TO FORM BY THE MID/LATE AFTERNOON
HOURS AT FIRST RELATIVELY UNORGANIZED...WITH A GRADUAL INCREASE FROM
THE WEST BY AND AFTER 00Z SUN. AS USUAL...IT APPEARS TO BE A RACE
BETWEEN STORM DEVELOPMENT AND LOSS OF DAYTIME PEAK INSTABILITY. BUT
IN THE END...SOME STORMS MAY BECOME STRONG TO SEVERE MAINLY ACROSS
THE FAR WESTERN ZONES CLOSER TO THE OHIO RIVER BUT THE THREAT
APPEARS MARGINAL AT BEST. STRONG WINDS APPEAR TO BE THE MAIN HAZARD
WITH DCAPE VALS OVER 1K J/KG JUST TO THE SOUTHWEST OF THE FORECAST
AREA BUT EL/S ARE SUFFICIENTLY TALL FOR SOME LARGE HAIL.
LITTLE CHANGE FROM PREV FORECAST WITH REGARD TO THE REMAINDER OF THE
OVERNIGHT HOURS. A MORE GENERAL CONVECTIVE RAINFALL WITH SOME
THUNDER PERHAPS WILL PUSH INTO THE AREA WITH GOOD DEEP LAYER
MOISTURE AND A PREFRONTAL TROUGH-TYPE FEATURE. STILL EXPECTING
ROUGHLY A HALF-INCH OR SO ACROSS THE AREA...AND SOME LOCALIZED WATER
ISSUES COULD BE POSSIBLE SHOULD HEAVY SHOWERS/STORMS PASS OVER THE
SAME LOCATION BUT NOTHING WIDESPREAD EXPECTED. SUNDAY...AGAIN LITTLE
CHANGE FROM PREV FCST WITH THE MAIN AXIS OF DEEP MOISTURE PUSHING
ACROSS DURING THE MORNING HOURS WITH HIGH CHANCE POPS CONFINED
MAINLY TO CKB-CRW AND POINTS EAST BY 18Z. ACTUAL COLD FRONT HOWEVER
STILL LAGS WELL BEHIND AND ONLY ENTERING THE NW ZONES BY END OF THE
PERIOD. INHERITED MAX TEMPS AROUND 80 FOR LOWLANDS STILL LOOK ON
TRACK.
&&
.SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY NIGHT/...
GFS/ECMWF SHOW COLD FRONT OVER THE OH RIVER BY 00Z MONDAY. SHOWERS
AND STORMS WILL BE POSSIBLE ALONG THE FRONT...DIMINISHING IN
INTENSITY AND COVERAGE BY EARLY MONDAY MORNING.
THE FRONT BRINGS A WIND SHIFT FROM THE NORTHWEST ALOFT MONDAY
NIGHT...WHILE AT THE SFC COULD BECOME LIGHT AND VARIABLE...OR
CALM. THEN...FLOW BECOMES NORTHERLY LATER MONDAY AND MONDAY NIGHT
TO BRING COOLER TEMPERATURES...MILD AFTERNOON...AND RELATIVELY
COLDER NIGHTS ARE EXPECTED THROUGH TUESDAY NIGHT.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
WEAK SEMI ZONAL FLOW ALOFT AND NO VORT MAX FROM SHORTWAVES
SUGGEST BROAD HIGH PRESSURE WILL REMAIN IN CONTROL THROUGH EARLY
THURSDAY. THIS WILL CONTINUE TO CLEARING CONDITIONS...EXCEPT FOR
LOW LEVEL DIURNAL CU DURING THE AFTERNOON HOURS.
NEAR NORMAL TEMPERATURES EXPECTED THURSDAY ON. TWEAKED DOWN WPC
TEMPERATURE A BIT.
A WARM FRONTAL BOUNDARY FORMS ACROSS OH INTO SOUTHEAST OH
THURSDAY...UNDER SOUTHERLY FLOW. THE SOUTHERLY WINDS WILL ALSO
RESULT IN INCREASING LOW-LEVEL MOISTURE AND THE CHANCES FOR
SHOWERS AND STORMS...MAINLY DIURNAL IN NATURE...WILL ALSO RETURN
THROUGH THE REMAINDER OF THE PERIOD.
&&
.AVIATION /19Z SATURDAY THROUGH THURSDAY/...
12Z SATURDAY THRU 12Z SUNDAY...
VFR CONDITIONS TO CONTINUE...AFTERNOON HIGH BASED CU WILL RESULT
IN SCATTERED SHOWERS AND STORMS WITH MOST AREAS REMAINING DRY.
THERE IS A SLIGHT RISK FOR SEVERE THUNDERSTORMS WEST OF THE OHIO
RIVER LATER THIS AFTERNOON AND EVENING.
AFTER 00Z...BAND OF CONVECTION WELL AHEAD OF A COLD FRONT WILL
SLOWLY MOVE EASTWARD AND REACH THE OHIO RIVER BY 06Z SUNDAY...THE
I79 CORRIDOR BY 09Z...AND THE MOUNTAINS BY 12Z. GENERALLY MVFR
CONDITIONS IN THIS RAIN BAND...WITH AN EMBEDDED THUNDERSTORM
POSSIBLE. WILL USE VCTS IN TAFS.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z SUNDAY...
FORECAST CONFIDENCE...MEDIUM.
ALTERNATE SCENARIOS: TIMING OF BAND OF CONVECTION LATER PART OF
PERIOD MAY VARY.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
UTC 1HRLY 18 19 20 21 22 23 00 01 02 03 04 05
EDT 1HRLY 14 15 16 17 18 19 20 21 22 23 00 01
CRW CONSISTENCY H H H H H H H H H H H H
HTS CONSISTENCY H H H H H H H H H H H H
BKW CONSISTENCY H H H H H H H H H H H H
EKN CONSISTENCY H H H H H H H H H H H H
PKB CONSISTENCY H H H H H H H H H H H H
CKB CONSISTENCY H H H H H H H H H H H H
AFTER 18Z SUNDAY...
IFR POSSIBLE IN SHOWERS AND THUNDERSTORMS SUNDAY INTO SUNDAY
NIGHT...AND IN POST-RAIN FOG AND LOW CLOUDS LATE SUNDAY NIGHT INTO
MONDAY MORNING.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...JMV/26
NEAR TERM...JMV/50
SHORT TERM...ARJ
LONG TERM...ARJ
AVIATION...26/JM
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
328 PM EDT SAT JUN 1 2013
.SYNOPSIS...
WEATHER SYSTEM OVER THE WESTERN GREAT LAKES WILL SHIFT EASTWARD
TONIGHT...DRAGGING A COLD FRONT THROUGH THE OHIO VALLEY LATER
TONIGHT AND SUNDAY. THIS WILL PROMPT SEVERAL ROUNDS OF SHOWERS AND
STORMS FOR THE AREA...BEFORE A DRYING TREND TAKES HOLD FOR SUNDAY
NIGHT...LASTING INTO THE MIDDLE OF NEXT WEEK. A COOLER AND DRIER
AIRMASS WILL DOMINATE THROUGH THIS TIME PERIOD.
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
FOR BEING AS CLOSE AS WE ARE TO GETTING INTO A POTENTIAL SEVERE
WEATHER EVENT...UNCERTAINTY REMAINS VERY HIGH GIVEN HOW EXTENSIVE
FRIDAY CONVECTIVE COMPLEXES HAVE MODULATED THE AVAILABLE
INSTABILITY AND SHIFTED WEAK FOCI FOR CONVECTIVE INITIATION RATHER
SUBSTANTIALLY. AMALGAM OF CONVECTION ALLOWING MODELS /CAMS/
RUNNING EXPERIMENTALLY AT 3-4KM RESOLUTION HAVE BEEN WILD AND
ERRATIC IN THEIR SOLUTIONS FROM RUN TO RUN WITH CONVECTIVE
COVERAGE/INTENSITY WHETHER IT BE HRRR OR NCEP VERSIONS OF HIRESW-
NMM/ARW WINDOWS. THUS - UNCERTAINTY IS HIGH AND DO NOT HAVE GOOD
FEELING HOW NEXT 12 HOURS WILL EVOLVE.
18Z MESOANALYSIS /SUBJECTIVE AND OBJECTIVE/ SHOWS ERN EDGE OF
DECAYED MCS FROM LAST NIGHT NOW FROM AREAS AROUND CVG SOUTHWEST TO
NEAR BOWLING GREEN KENTUCKY. EAST OF THIS DEMARCATION - MAINLY
ALONG AND EAST OF I-71 IN KY/OHIO AS OF RIGHT NOW - THE
ATMOSPHERE IS SUPPORTIVE OF AT LEAST STRONG TO MARGINALLY SEVERE
STORMS WITH 0-6KM BULK SHEAR FROM 30 TO 40 KTS...AND MLCAPE FROM
750 TO 1250 J/KG BASED ON THE LOCAL OBSERVATIONS INTEGRATED INTO
LAPS ANALYSIS. WEST OF THIS AREA...IT HAS BEEN SLOWER TO RECOVER
DUE TO DEEPER/STRONGER INFLUENCE FROM RESIDUAL OUTFLOWS/COLD POOLS
FROM THE OVERNIGHT MCS. BUT THIS AREA IS DESTABILIZING MILDLY TOO.
BASED ON A NUMBER OF DIFFERENT CAM RUNS...AND THE MESOA MENTIONED
ABOVE...FEEL THE BEST SHORT TERM THREAT FOR SEVERE WEATHER WILL BE
FROM INCREASING COVERAGE AND INTENSITY OF DISCRETE CELLS NOW OVER
CNTL KY AND UPSCALE GROWTH OF LEADING EDGE OF OLD MCS AREA OVER WRN
KY - WHICH SYNOPTIC SCALE MODELS HAVE BEEN LATCHING ONTO AS A
POSSIBLE AREA OF GROWTH. THIS ALL COULD CONGEAL AND GIVE A
DAMAGING WIND THREAT VIA A CLUSTER OF STORMS IN THE 5 PM TO 9 PM
TIMEFRAME ALONG AND EAST OF A CVG TO CMH LINE. THIS AREA HAS THE
LARGEST DCAPE POOL FOR SEVERE WIND GUST POTENTIAL TO WORK FROM AS
WELL AS MLCAPE...BUT IS DISPLACED EAST A BIT FROM DEEPER SHEAR.
HOWEVER...THERE IS ENOUGH SHEAR IN THE 0-3KM LAYER /30KTS/ THAT A
BOWING SEGMENT OR TWO WOULD BE POSSIBLE. SPC GRABBED A PART OF
THIS AREA IN RECENT SWOMCD WITH MARGINAL CONFIDENCE FOR A
WATCH...SO RADAR TRENDS WILL BE MONITORED UPSTREAM FOR
GROWTH/ORGANIZATION OF STORMS. THE TORNADO THREAT IS NOT TOTALLY
ZERO...LOW LEVEL SHEAR VIA A PERSISTENT SWLY /MOIST/ LLJ IS
KEEPING 0-1KM SHEAR AROUND 20KTS...BUT FLOW IS RATHER
UNIDIRECTIONAL. A LOCAL BACKING TO SLY WOULD MAKE THINGS MORE
INTERESTING BUT THE LARGER SCALE PATTERN DOESN`T REALLY SUPPORT
THAT - SO OVERALL TOR THREAT IS NOT HIGH PER CURRENT
ANALYSIS/FORECASTS. GIVEN MARGINAL INSTBY...HAIL WOULD BE AN
OUTLIER GIVEN THE MOIST ADIABATIC MID LEVEL LAPSE RATES AS WE/VE
BEEN DOWNSTREAM OF THE HIGH MOISTURE CONTENT DECAYING MCS MOST OF
THE DAY.
OVERNIGHT...STRONGER SYNOPTIC SCALE FORCING MOVES ACROSS THE GREAT
LAKES AS DEAMPLIFYING SHORTWAVE TROUGH SLIDES ACROSS THE AREA WITH
ATTENDANT COLD FRONT. EXPECT...AT SOME POINT...A LINE OF SHOWERS
AND STORMS TO BEGIN TO CONGEAL/INCREASE ALONG THIS FEATURE AS WELL
BUT GIVEN ITS EXPECTED ARRIVAL THROUGH THE AREA...EXPECTING SEVERE
THREAT TO REMAIN RATHER MARGINAL WITH THIS. STRONG LOW LEVEL SHEAR
WITH ANY LINE OF SHOWERS/STORMS NEEDS TO BE WATCHED...AND TONIGHT
WILL BE NO EXCEPTION BUT THE LARGE POOL OF MINIMUM INSTABILITY
OVER INDIANA IS GOING TO REALLY WORK AGAINST SOMETHING REALLY
TAKING OFF. WHILE CAM RUNS /AS MENTIONED ABOVE/ ARE REALLY ALL
OVER THE PLACE WITH REGARDS TO RAIN CHANCES TONIGHT...STUCK WITH
STRONGER FORCING /RIGHT ENTRANCE REGION OF JET AND INCREASING PV
AND ATTENDANT LOW LEVEL FRONTAL ZONE/ TO DRIVE HIGHER RAIN/STORM
CHANCES LATE EVENING AND OVERNIGHT...A CONTINUATION OF PREVIOUS
FORECAST. STILL THINK /GIVEN MOIST PWATS ABOVE SEASONAL NORMS/
LOCALLY HEAVY RAIN RATES AND PERHAPS SOME LOCALIZED RUNOFF ISSUES
WILL BE A PROBLEM WITH ANY STORMS THAT LINGER OVER AN AREA MORE
THAN AN HOUR.
&&
.SHORT TERM /6 AM SUNDAY MORNING THROUGH SUNDAY NIGHT/...
SECONDARY WAVE ALOFT FINALLY ESCORTS THE TROUGH AXIS OUT OF THE
AREA TOMORROW AND THIS ALLOWS A WEAK SECONDARY FRONT TO DEVELOP
AND PUSH THROUGH DURING THE DAY. MAY BE A BROKEN BAND OF SHOWERS
ALONG THIS FEATURE BY MID AFTERNOON...SO CARRIED THIS CHANCE FROM
NW-SE ACROSS THE AREA DURING THE LATE MORNING INTO THE EARLY
EVENING. MUCH COOLER/DRIER AIRMASS ARRIVES ON THE HEELS OF THIS
FRONT AND MAKES FOR A COMFORTABLE SUNDAY NIGHT WITH LOWS DOWN INTO
THE 50S UNDER CLEARING SKIES.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
PERIOD BEGINS WITH HIGH PRESSURE CENTERED OVER THE UPPER MS VALLEY.
THE HIGH WILL BUILD SE INTO THE LOWER GREAT LAKES THROUGH TUESDAY.
HIGHS ON MONDAY WILL BE COOL...RANGING FROM THE UPPER 60S TO THE
LOWER 70S WHICH WILL BE ABOUT 5 TO 10 DEGREES BELOW NORMAL FOR EARLY
JUNE. TEMPERATURES WILL FALL INTO THE UPPER 40S TO LOWER 50S MONDAY
NIGHT. 12Z MODELS HAVE COME IN A LITTLE WARMER FOR TUESDAY. SO TOOK
A CONSENSUS FORECAST AND RAISED HIGHS FOR TUESDAY INTO THE LOWER TO
MID 70S.
ON WEDNESDAY THE SFC HIGH PRESSURE IS FORECAST TO SLIDE EAST. THE
ECMWF IS THE QUICKEST WITH THE RETURN PCPN...BUT THE REMAINING
MODELS KEEP THE FA DRY...SO LEANED TOWARDS THE MAJORITY.
WEDNESDAY NIGHT INTO THURSDAY AS WRMFNT DEVELOPS OVER THE OH VLY...
ATMOSPHERE BECOMES UNTIL STABLE AND IT LOOKS LIKE THERE WILL BE A
CHANCE OF SCT TSRA. THU NGT INTO FRI...H5 WAVE SWINGS UP THE OH VLY
ADDING EXTRA LIFT AND IT DRIVES A CDFNT ACROSS THE REGION KEEPING
CHC OF CONVECTION IN THE FORECAST. DRIER AIR TRIES TO BUILD IN FOR
SATURDAY.
&&
.AVIATION /19Z SATURDAY THROUGH THURSDAY/...
SOUTHWEST WINDS WILL CONTINUE TO GUST AROUND 20-25 KTS THIS
AFTERNOON. STILL A STUBBORN MID TO HIGH CLOUD DECK OVER MOST OF THE
AREA ALTHOUGH SCT LIGHT SHOWERS ARE COMING TO AN END. WATCHING FOR
POSSIBLE REDEVELOPMENT OF SHOWERS AND THUNDERSTORMS LATER THIS
AFTERNOON. IF THIS MATERIALIZES...AND CONFIDENCE IS NOT
PARTICULARLY HIGH BASED ON LATEST HIGH RESOLUTION MODEL
SOLUTIONS...THINKING THE BEST CHANCE WOULD BE AROUND THE EASTERN
TAF SITES AS THAT AREA HAS SEEN THE MOST DAYTIME HEATING SO FAR.
BETTER CHANCE FOR SHOWERS AND STORMS FOR ALL TAF SITES WILL COME
LATE THIS AFTERNOON AND EVENING AS A COLD FRONT APPROACHES FROM
THE WEST. THIS ACTIVITY WILL SPREAD FROM WEST TO EAST WITH THE
POSSIBILITY OF A FEW STRONG TO SEVERE STORMS CONTAINING BRIEF YET
STRONG SHIFTING WINDS AS THEY PASS. MVFR/IFR CIGS AND VSBYS WILL
BE POSSIBLE WITH ANY STORMS LATE THIS AFTERNOON AND EVENING.
CIGS WILL LIKELY REMAIN MVFR LATE TONIGHT AND SOME LINGERING
SHOWERS WILL BE POSSIBLE AS THE COLD FRONT MOVES ACROSS THE AREA.
EXPECT A GRADUAL RETURN TO VFR CIGS SUNDAY MORNING.
OUTLOOK...NO SIGNIFICANT WEATHER EXPECTED.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...BINAU
NEAR TERM...BINAU
SHORT TERM...BINAU
LONG TERM...SITES
AVIATION...KURZ
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
520 PM EDT SAT JUN 1 2013
.SYNOPSIS...
BERMUDA HIGH PRESSURE WILL SHIFT OFF THE COAST OF THE CAROLINAS AS A
COLD FRONT APPROACHES FROM THE WEST LATE SUNDAY NIGHT INTO EARLY
MONDAY. THE FRONT WILL REACH THE COAST EARLY TUESDAY...FOLLOWED BY
DRY HIGH PRESSURE MOVING BACK INTO THE AREA AND REMAINING THROUGH THE
MIDDLE OF NEXT WEEK.
&&
.NEAR TERM /THROUGH SUNDAY/...
AS OF LATE AFTERNOON...SO FAR EVERYTHING APPEARS IN ORDER...WITH A
FLAT CU FIELD OVER OUR EASTERN FA...AND AN ENHANCED CU FIELD FROM
CENTRAL GA NEWD UP THROUGH THE WRN SC UPSTATE AND AND SW MOUNTAINS
OF NC. THE HRRR CONVECTIVE RUNNING MODEL INDICATES THAT SECONDARY
AREA CU FIELD...TO OUR WEST AND SOUTHWEST...AS PERHAPS A GENESIS FOR
SHOWERS OR TSTMS DEVELOPING THIS EVENING. CURRENT POPS ARE
ESTABLISHED NICELY.
PREVIOUS DISCUSSION...
AS OF 230 PM EDT...AN UPPER RIDGE PERSISTS ACROSS THE SOUTHEAST THIS
AFTERNOON AS HEIGHTS FALL ACROSS THE MS RIVER VALLEY. FORECAST
SOUNDINGS UNDER THIS RIDGE CONTINUE TO SHOW VERY LIMITED CAPE...BUT
WITH SLIGHTLY MORE INSTABILITY IN SW PARTS OF THE FORECAST AREA. THE
LATEST CONVECTION ALLOWING MODELS FEATURE LOW END COVERAGE LATE THIS
AFTN AND THIS EVENING IN THE FAR SRN PIEDMONT AND ALSO IN THE
EXTREME SRN MTNS WHERE SRLY UPSLOPE FLOW WILL BE BEST.
PLUS...REGIONAL RADARS ALREADY HAVE DECENT COVERAGE FROM THE TN
VALLEY TO THE AL/GA BORDER FROM AN ERN GULF OF MEXICO MOISTURE
FETCH...SO WILL CONTINUE TO ADVERTISE MORE SOLID SCT COVERAGE IN THE
SW MTNS THROUGH EVENING.
THE APPROACHING...BUT DAMPENING...UPPER TROUGH WILL THEN START TO
BRING SOME UPPER FORCING TO THE REGION OVERNIGHT THROUGH SUNDAY. 250
MB WIND DIVERGENCE ARRIVES OVER THE MTNS LATE TONIGHT...AND THEN
LOBES OF WEAK 850 TO 500 MB DPVA SHOULD PUSH ACROSS THE FORECAST
AREA THROUGH SUNDAY. AT LOW LEVELS...IMPROVING SRLY FLOW ALONG WITH
THE IMPROVED GULF MOISTURE TAP SHOULD ALLOW FOR PRECIPITATION
COVERAGE TO INCREASE ACROSS THE SRN APPALACHIANS OVERNIGHT...WITH
MOISTURE AND CONVECTIVE COVERAGE INCREASING TO CATEGORICAL W AND
LIKELY E BY LATE SUNDAY AFTN. FLOW IN THE SFC TO 6 KM LAYER SUNDAY
APPEARS FAIRLY UNIDIRECTIONAL FROM THE SW WITH ONLY LIMITED SPEED
SHEAR. INSTABILITY WILL BE LIMITED BY SUB 6 DEG C/KM LAPSE RATES AND
MLCAPE VALUES LESS THAN 1000 J/KG THROUGHOUT. THE SEVERE WX THREAT
THUS APPEARS QUITE LIMITED AS WE STAY SOUTH OF THE BETTER DYNAMICS
THROUGH SUNDAY AFTERNOON. WILL FEATURE A SMALLER DIURNAL RANGE ON
TEMPS THAN IN PREVIOUS DAYS WITH MUCH MORE ABUNDANT CLOUD COVER.
&&
.SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY/...
AS OF 230 PM SATURDAY...MODELS CONTINUE TO INDICATE THAT AN UPPER
TROUGH AXIS WILL CROSS THE EASTERN STATES SUN NIGHT INTO MON PUSHING
A TRAILING SURFACE COLD FRONT THROUGH THE FORECAST AREA. THE FRONT
IS EXPECTED TO CROSS THE MTNS SUN NIGHT AND BECOMES STATIONARY IN
THE VICINITY OF I-85 CORRIDOR ON MONDAY. THE FRONT THEN PUSHES OFF
TO FURTHER EAST MON NIGHT AS CANADIAN SURFACE HIGH PRESSURE CENTERED
OVER THE GREAT LAKES REGION RIDGING INTO THE REGION. THE BEST CHANCE
OF HEAVIER PRECIP WILL OCCUR SUN NIGHT AS A LINE OF VORT MAX ALONG
WITH GOOD LLVL CONVERGENCE ALONG THE FRONT MOVES ACROSS THE CWA.
HOWEVER...SEVERE WEATHER LOOKS TO BE MINIMAL AS MODELS CONTINUE TO
REVEAL WEAK BUOYANCY ALONG WITH RELATIVELY WEAKER UNIDIRECTIONAL
WIND SHEAR. MAIN THREAT WILL BE LOCALIZED HEAVY RAINFALL ESPECIALLY
IN THE NC MOUNTAINS. TOTAL PRECIP AMOUNT FROM THIS EVENT WILL BE
AROUND 1.0 TO 1.5 INCHES WITH HIGHER AMOUNTS POSSIBLE IN FAVORED
UPSLOPE AREAS IN HIGHER TERRAIN. PRECIP GRADUALLY TAPER OFF FROM
WEST OT EAST LATE MON AS THE FRONT MOVES OFF TO THE EAST AND DRY
AIRMASS MOVES IN FROM THE NORTH. CONDITIONS LOOK DRY AS CANADIAN
HIGH PRESSURE BUILDS IN FROM THE NORTH. TEMPERATURES WILL REMAIN A
FEW DEGREES BELOW NORMAL THROUGH THE PERIOD.
&&
.LONG TERM /TUESDAY NIGHT THROUGH FRIDAY/...
AS OF 145 PM SATURDAY...THE LATEST GLOBAL MODELS ARE IN GOOD
AGREEMENT WITH THE OVERALL SYNOPTIC PATTERN DURING THE MEDIUM RANGE
PERIOD.
A WEAK UPPER RIDGE BUILDS IN FROM THE WEST WITH SURFACE CANADIAN
HIGH CENTERED OVER QUEBEC RIDGING INTO THE FORECAST AREA TUE NIGHT
INTO WED. THIS WILL RESULT IN MOSTLY DRY CONDITIONS WITH
TEMPERATURES A FEW DEGREES BELOW NORMAL IN PERSISTENT NE FLOW. THE
FLOW BECOMES EASTERLY BY THURSDAY AS THE SURFACE RIDGE OF HIGH
WEAKENS AND SHIFT EAST. WITH INCREASING ATLANTIC MOISTURE...HAVE
CARRIED SLIGHT CHANCE POPS OVER THE PIEDMONT WITH HIGHER POPS IN THE
MOUNTAINS. AN UPPER TROUGH WILL APPROACH FROM THE CENTRAL STATES
FRI...PUSHING A TRAILING SURFACE COLD FRONT THROUGH THE FORECAST
AREA LATE FRI/EARLY SAT. MEANWHILE...MODELS AGREE THAT A TROPICAL
LOW OVER THE GULF OF MEXICO WILL TRACK NE ACROSS FL THU...AND OFF
THE SE COAST BY FRI. HOWEVER...THIS SYSTEM WILL THEN QUICKLY LIFT
FURTHER NE SAT AS THE UPPER TROUGH SWINGS ACROSS THE EASTERN STATES.
HAVE KEPT HIGHER POPS ON FRI NIGHT/SAT AS THE COLD FRONT CROSSES THE
REGION. TEMPERATURES WILL REMAIN 2-3 DEGREES BELOW NORMAL THROUGH
THE REST OF THE PERIOD.
&&
.AVIATION /22Z SATURDAY THROUGH THURSDAY/...
AT KCLT...STEADY SW FLOW AROUND 10 KT OR LESS IS EXPECTED THROUGH
MOST OF THE TERMINAL FORECAST PERIOD. THERE COULD BE A FEW LOW END
GUSTS WITH PEAK MIXING LATE THIS AFTN. EXPECT MOSTLY SCT VFR LEVEL
CUMULUS THROUGH EVENING...BUT WITH CIGS FILLING BACK IN AND LOWERING
FROM THE SW OVERNIGHT AS ADDITIONAL MOISTURE SURGES IN ON IMPROVING
SRLY 850 MB FLOW. THERE IS FAIRLY STRONG CONSENSUS AMONG THE MOS ON
A DOWNWARD TREND THROUGH MVFR CIGS AFTER 08Z INTO IFR CIGS TOWARD
DAYBREAK SUNDAY...AND THIS WILL BE ADVERTISED. SHOWER COVERAGE WILL
LIKELY INCREASE FROM THE W SUNDAY MORNING...WITH SCT TSRA CHANCES
IMPROVING TOWARD THE END OF THE PERIOD.
ELSEWHERE...ISOLD TO SCT SHRA/TSRA COVERAGE SHOULD REMAIN GENERALLY
W OF A KAVL TO KAND LINE THROUGH THE EVENING HOURS...BUT WITH MTN
SHOWERS LIKELY INCREASING OVERNIGHT. SURGING SRLY FLOW MOISTURE FROM
THE GULF OF MEXICO SHOULD ALSO PRODUCE FAIRLY WIDESPREAD IFR TO MVFR
CIGS DURING THE OVERNIGHT HOURS. COVERAGE OF THE SHRA AND VCTS WILL
THEN EXPAND EASTWARD THROUGH THE LATER MORNING HOURS ON
SUNDAY...WITH LINGERING RESTRICTIVE CEILINGS. EXPECT FAIRLY STEADY
SRLY WINDS AROUND 10 KT THROUGH THE PERIOD.
OUTLOOK...SHRA/TSRA CHANCES...WITH ASSOCIATED RESTRICTIONS...WILL
PERSIST SUNDAY NIGHT IN MONDAY. GRADUAL DRYING UNDER HIGH PRES IS
THEN EXPECTED THROUGH MID WEEK...WITH CONDITIONS THEN BECOMING
UNSETTLED AGAIN MID TO LATE WEEK AS MOISTURE RETURNS.
CONFIDENCE TABLE...
19-01Z 01-07Z 07-13Z 13-19Z
KCLT HIGH 100% HIGH 100% HIGH 80% HIGH 84%
KGSP HIGH 100% HIGH 100% MED 78% HIGH 86%
KAVL HIGH 100% HIGH 100% HIGH 93% HIGH 94%
KHKY HIGH 100% HIGH 100% HIGH 89% HIGH 90%
KGMU HIGH 100% HIGH 100% HIGH 80% HIGH 93%
KAND HIGH 100% HIGH 88% MED 75% HIGH 88%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...PAT
NEAR TERM...HG
SHORT TERM...JOH
LONG TERM...JOH
AVIATION...HG
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
304 PM CDT SAT JUN 1 2013
.DISCUSSION...
AT 19Z...A COLD FRONT EXTENDED FROM ABOUT PARIS TO BROWNWOOD TO
MIDLAND. A WEAK TROUGH OF LOW PRESSURE EXTENDED FROM TEXARKANA TO
ABOUT HUNTSVILLE. THE FRONT WILL CONTINUE TO SLIDE SOUTH TOWARD SE
TX OVERNIGHT. NAM 12 FCST SOUNDINGS SHOW PW VALUES APPROACHING
2.00 INCHES AT KCLL AND AROUND 1.8 INCHES AT KIAH WITH LITTLE TO
NO CAPPING. DEEP LAYER MOISTURE AND MODEST SURFACE CONVERGENCE
SHOULD YIELD A GOOD CHANCE OF RAIN OVER THE NORTH TONIGHT.
CONFIDENCE IS LESS CERTAIN OVER THE SOUTHERN HALF OF THE CWA AS
SURFACE CONVERGENCE WEAKENS CONSIDERABLY AFTER MIDNIGHT. WILL GO
WITH LIKELY POPS OVER THE NORTH AND TAPER TO LOW END CHANCE POPS
CENTRAL AND SLIGHT CHANCE ALONG THE COAST. THE RAP INITIALIZED
WELL SO WILL LEAN TOWARD THE RAP AND OTHER HI-RES MODELS IN THE
SHORT TERM. THERE COULD BE SOME TRAINING OF STORMS OVER THE NORTH
TONIGHT AND AM A BIT CONCERNED THAT SOME HEFTY RAINFALL TOTALS
WILL BE POSSIBLE NORTH OF A BRENHAM TO TRINITY LINE. WILL REISSUE
THE HWO TO HIGHLIGHT THIS POSSIBILITY.
MOISTURE LEVELS WANE QUICKLY SUNDAY MORNING. UPPER LEVEL JET
ENERGY LOOKS NEUTRAL WITH UPPER LEVEL CONVERGENCE INCREASING
DURING SUNDAY AFTN. WILL TRIM POPS FOR SUNDAY AND END ALL RAIN
CHANCES BY SUNDAY EVENING. IT STILL LOOKS WARM ON SUNDAY WITH MAX
TEMPS NEAR 90 DEGREES. UPPER LEVEL RIDGING TRIES TO BUILD INTO
SOUTH TEXAS EARLY NEXT WEEK. WENT CLOSER TO THE WARMER EUROPEAN
GUIDANCE. MODELS DIVERGE A BIT TOWARD NEXT WEEKEND. THE ECMWF IS
STRONGER WITH SOME S/WV ENERGY ON FRIDAY AND DEEPER WITH AN UPPER
LEVEL TROUGH ON SUNDAY. THE GFS AND CANADIAN LOOK SOMEWHAT SIMILAR
TO THE ECMWF BUT WEAKER. THE GRIDS HAVE 20 POPS FOR FRI/SAT AND
FEEL THAT IS A GOOD PLACE TO START. WILL WAIT AND SEE IF MODELS
CAN BUILD A CONSENSUS FOR HIGHER RAIN CHANCES.
&&
.MARINE...
WILL ALLOW THE RIP CURRENT STATEMENT TO EXPIRE AT 00Z AS WINDS
CONTINUE TO RELAX. LIGHT EAST TO SOUTHEAST WINDS WILL BE THE NORM
THROUGH THE MAJORITY OF NEXT WEEK. THE LACK OF ANY SIGNIFICANT
PRESSURE GRADIENT...DUE TO NORTH-NORTHEASTERN CENTERED SURFACE
RIDGING...WILL MAINTAIN A TAME MARITIME WIND FIELD.
GENERALLY...SEAS HEIGHTS WILL BE AN AVERAGE 2 TO 3 FEET. THERE IS
A POSSIBILITY OF A LATE WEEK FAR OFFSHORE SWELL. THIS WILL BE
DEPENDENT UPON THE DEVELOPMENT AND EVOLUTION OF AN EASTERN GULF
TROUGH OF LOW PRESSURE. 31
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 72 90 66 91 70 / 60 20 10 0 0
HOUSTON (IAH) 75 91 67 92 70 / 40 30 10 0 0
GALVESTON (GLS) 78 87 74 87 76 / 20 30 10 0 0
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...HIGH RIP CURRENT RISK UNTIL 7 PM CDT THIS EVENING FOR THE
FOLLOWING ZONES: BRAZORIA...GALVESTON.
GM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS SPOKANE WA
1040 AM PDT Sat Jun 1 2013
.SYNOPSIS...
Most of the region will experience dry conditions today. The best
chance of showers, however, will be near the Canadian border this
afternoon as Sundays upper low approaches. This relatively strong
storm system will bring a cool- down with showers...thunderstorms and
breezy conditions for Sunday and Monday. The greatest threat of
precipitation will be across the eastern third of Washington and
the Idaho Panhandle Sunday. A drying and warming period will
greet the remainder of the new work week with temperatures
rising into the upper 70s and 80s by Tuesday.
&&
.DISCUSSION...
Update: Water vapor satellite imagery at 8 am showed a well
defined vort max over Vancouver Island moving into southern
British Columbia. Abundant mid and high clouds associated with
this wave will continue to stream into the Inland Northwest today
and sky cover has been adjusted upward a bit for the morning
hours mainly areas along and north of I-90 where mid level clouds
are more extensive. Latest HRRR falls in line with general model
consensus of showers developing over the mountains of the East
Slopes of the Cascades after about noon or 1 pm...and the north
portion of the Okanogan Highlands after 2 or 3 pm...with the bulk
of the showers north of the Canadian Border. With the best
instability and lift associated with this wave passing over
southern BC this idea makes sense. GFS and NAM show also show CAPE
values of around 200 J/KG which could result in a stray
thunderstorm. With low confidence of any lightning materializing
will leave out of forecast through the afternoon. The remainder of
the area is expected to remain dry through the afternoon. Made
some minor POP and weather adjustments based on above reasoning.
JW
&&
.AVIATION...
18Z TAFS: An upper level trough will spread an increase in mid and
high clouds over the region today...with showers and isolated
thunderstorms mainly north of the area in southern British Columbia
although a few showers are expected along the East Slopes of the
Cascades. Showers chances will increase over northern Washington
overnight and across the remainder of Eastern Washington and North
Idaho Sunday morning along with a slight chance of thunderstorms as
mid level moisture and instability increases. Most of the showers
through 18z Sunday will have CIGS 7-10k ft MSL with CIGS remaining
VFR at the TAF sites. JW
&&
.PRELIMINARY POINT TEMPS/POPS...
Spokane 71 49 64 48 71 51 / 0 30 70 60 20 10
Coeur d`Alene 71 46 61 46 69 47 / 0 30 80 70 30 10
Pullman 71 45 65 45 69 47 / 0 20 60 60 20 10
Lewiston 78 53 73 52 75 53 / 0 10 50 50 10 10
Colville 74 46 69 47 77 49 / 10 50 60 50 20 10
Sandpoint 70 43 63 45 67 45 / 10 40 80 70 40 20
Kellogg 68 46 61 46 63 46 / 0 20 80 80 40 20
Moses Lake 76 49 76 50 81 52 / 0 10 10 10 0 0
Wenatchee 76 52 72 53 79 54 / 0 10 10 10 0 0
Omak 73 48 72 48 78 50 / 10 40 20 20 0 0
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...None.
&&
$$
FORECAST DISCUSSION FOR ROUTINE AFTERNOON FORECAST ISSUANCE
.SYNOPSIS...
ISSUED AT 254 PM CDT SAT JUN 1 2013
TURNING COOLER AND LESS HUMID...WITH TEMPERATURES RETURNING TO
SOMEWHAT BELOW NORMAL LEVELS.
UPR PATTERN ACRS NOAM WL TRANSITION BACK INTO A MORE TYPICAL
EARLY SUMMER REGIME AS DEEP UPR TROF OVER THE GREAT LAKES RGN
SHIFTS OFF TO THE NE. IN ITS WAKE...A LOWER AMPLITUDE AND WEAKER
BAND OF WESTERLIES WL REMAIN ACRS THE NRN CONUS. THOUGH INITIALLY
PROGRESSIVE...WEAK UPR TROF WL EVENTUALLY SET-UP OVER THE NRN
PLAINS OR WESTERN LAKES RGN.
THE WARM AND RATHER HUMID AIR STILL LINGERING ACRS THE AREA TDA
WL BE REPLACED BY COOLER AND LESS HUMID CONDITIONS IN THE WAKE OF
THE DEPARTING UPR TROF. TEMPERATURES WL SETTLE BACK TO BLO NORMAL
FOR MOST OF THE REST OF THE PERIOD. THERE WL BE AT LEAST A COUPLE
OPPORTUNITIES TO PICK UP SOME PCPN...SO AMOUNTS WL PROBABLY END UP
NR NORMAL AT MOST LOCATIONS.
&&
.SHORT TERM...TONIGHT AND SUNDAY
ISSUED AT 254 PM CDT SAT JUN 1 2013
PESKY UPPER LOW THAT HAS BROUGHT SEVERAL DAYS OF UNSETTLED
WEATHER TO THE FORECAST AREA IS FINALLY ON THE MOVE AND WILL SHIFT
EAST ACROSS THE FORECAST AREA OVERNIGHT. THIS WILL FINALLY END THE
SCATTERED SHOWER AND THUNDERSTORM ACTIVITY WE HAVE SEEN THE PAST
FEW DAYS.
NOTABLE INSTABLITY THAT HAS LINGERED ACROSS MAINLY THE EASTERN
HALF OF THE FORECAST AREA...IN CONCERT WITH A WEAK SHORT WAVE
DISTURBANCE MOVING NORTHEAST TOWARD THE FORECAST AREA...HAS
CONTRIBUTED TO A BAND OF SHOWERS AND EMBEDDED THUNDERSTORM
ACTIVITY ACROSS THE FOX VALLY NORTHEAST TOWARD ESCANABA MICHIGAN.
DESPITE FAVORABLE WETBULB ZERO HEIGHTS AROUND 8500 FEET AGL..ONLY
HAVE HAD A COUPLE REPORTS OF SOME PEA SIZE HAIL THUS FAR. WITH PW
VALUES STILL AROUND AN INCH...AND UPPER-LEVEL WINDS CONTINUING TO
WEAKEN AS UPPER TROUGH MOVES OVERHEAD...EXPECT A FEW OF THESE
STORMS TO BE EFFICIENT RAINFALL PRODUCEERS PRODUCING SOME BRIEF
HEAVY RAINFALL INTO THE EARLY EVENING. 18Z HRRR AND TO A LESSER
EXTENT THE GFS AND NAM...FOCUS THE BEST LIFT AND ASSOCIATED QPF OVER
THE NORTHEAST PORTION OF THE FORECAST AREA THIS EVENING. THIS SEEMS
REASONABLE GIVEN CURRENT RADAR TRENDS...THUS HAVE ADJUSTED THE QPF
AND POP ACCORDINGLY FOR THIS EVENING. AS UPPER TROUGH SWEEPS
ACROSS THE FORECAST AREA OVERNIGHT...THE ASSOCIATED SURFACE TROUGH
AND ATTENDAND SCATTERED SHOWER ACTIVITY WILL ALSO STEADLIY
PROGRESS EASTWARD. BASED ON THE LATEST RUN OF THE HRRR...ANTICIPATE
THE SURFACE TROUGH TO MOVE EAST OF THE FOX VALLEY BY AROUND
MIDNIGHT. SOME RESIDUAL LOW-LEVEL MOISTURE IN THE WAKE OF THE
SURFACE TROUGH MAY CONTRIBUTE TO A FEW LINGERING LIGHT SHOWERS OR
SPRINKLES OVER THE LAKE SHORE COUNTIES UNTIL ABOUT 12Z. RESIDUAL
LOW LEVEL MOISTURE REALLY DOES NOT GET SCOURED OUT UNTIL AFTER
ABOUT 16Z SO HAVE SLOWED CLEARING A FEW HOURS ON SUNDAY. BRISK
NORTWEST WINDS SUNDAY MORNING WILL SLOWLY DIMINISH AS THE DAY
PROGRESSES AS SURFACE HIGH PRESSURE SETTLES IN.
.LONG TERM...SUNDAY NIGHT THROUGH SATURDAY
ISSUED AT 254 PM CDT SAT JUN 1 2013
HIGH PRESSURE RIDGING SWD FM CANADA WL DOMINATE THE START OF THE
LONG-TERM PERIOD. THAT WL LEAD TO PLENTY OF SUNSHINE AND DRY
CONDITIONS. TEMPS WL FALL WELL BLO NORMAL AT NIGHT. LOOKS LIKE A
PRETTY GOOD CHC OF FROST ACRS THE N SUNDAY NIGHT...AND SOME OF THE
TYPICAL COLD SPOTS COULD EVEN EXPERIENCE A FREEZE. MONDAY NIGHT
MAY NOT BE QUITE AS COLD...BUT AT LEAST PATCHY FROST WL AGAIN BE
POSSIBLE ACRS THE N. WL PROBABLY EVENTUALLY NEED A FROST/FREEZE
HEADLINE FOR THE N FOR SUN NGT...WL HOLD OFF ISSUING THAT NOW AS
LATER FORECASTS HAVE A BETTER CHC OF DISCERNING EXACTLY HOW FAR S
AND E TO TAKE THE HEADLINE.
THE NEXT UPR TROF EMBEDDED IN THE WESTERLIES ACRS THE NRN CONUS
WL BE APPROACHING THE AREA TUE. THE MAJORITY OF THE MODELS DROVE
PCPN WELL E INTO THE FCST AREA DURING THE DAY. BUT IT SEEMS LIKE
DRY AIR WITH THE DEPARTING HIGH PRESSURE SHOULD BE ABLE TO DELAY
THE EWD PROGRESSION OF THE PCPN AT LEAST A LITTLE. SO OPTED TO
KEEP THE MORNING DRY AND THEN LIMIT POPS TO ABOUT THE WRN 1/4 OF
THE FCST AREA DURING THE AFTN.
THE BEST CHC OF PCPN WL COME MID-WK AS THE UPR TROF CROSSES THE
RGN.
&&
.AVIATION...FOR 18Z TAF ISSUANCE
ISSUED AT 121 PM CDT SAT JUN 1 2013
SCATTERED THUNDERSTORMS HAVE DEVELOPED OVER EASTCENTRAL AND
NORTHEAST WISCONSIN EARLY THIS AFTERNOON. BEST INSTABLITY EXISTS
OVER THIS AREA...THUS EXPECT THIS ACTIVITY TO BE THE MOST ROBUST
IN A CORRIDOR FROM OSHKOSH TO NEAR GREEN BAY TO MARINETTE. SOME OF
THE THESE STORMS WILL LIKELY CONTAIN SMALL HAIL UP TO THREE
QUARTER INCH IN DIAMTER AND WIND GUSTS TO 40 MPH. GENERALLY VFR
CIGS EXCEPT NEAR THUNDERSTORMS...WHERE MVFR CIGS AND VISIBLITIES
ARE LIKELY EXPECIALLY AT OSH...ATW AND GRB TAF SITES THIS
AFTERNOON. ACTIVITY SHOULD DIMINISH AND BECOME WEAKER AND MORE
SCATTERED AFTER 00Z THIS EVENING. AS UPPER-LEVEL LOW CONTINUES TO
MOVE ACROSS THE STATE TONIGHT EXPECT MORE WIDESPREAD MVFR CIGS
OVERNIGHT. HIGH PRESSURE SHOULD EVENTUALLY PUSH IN AFTER 15Z
SUNDAY ALLOWING FOR CLEARING SPREADING FROM WEST TO EAST.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS.......SKOWRONSKI
SHORT TERM.....ESB
LONG TERM......SKOWRONSKI
AVIATION.......ESB
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
218 PM CDT SAT JUN 1 2013
.SHORT TERM...(TONIGHT AND SUNDAY TONIGHT)
ISSUED AT 218 PM CDT SAT JUN 1 2013
WATER VAPOR IMAGERY SHOWING THE CLOSED LOW SLOWLY FILLING WITH THE
MAIN CIRCULATION CENTER ROTATING EAST ALONG THE MN/IA BORDER. AT THE
SURFACE...LOW PRESSURE WAS CENTERED OVER SOUTHWEST WI WITH A COLD
FRONT/DRYLINE EXTENDING FROM CENTRAL INTO SOUTHWEST WI. STRONGER
CONVECTION WAS FIRING AHEAD OF THE DRYLINE OVER EASTERN WI IN AN
AXIS OF HIGHER DEWPOINT/INSTABILITY AXIS AND 25-35KT 0-3KM BULK
SHEAR. MEANWHILE...RADAR MOSAIC WAS ALSO SHOWING WEAKER
SHOWER/THUNDERSTORM ACTIVITY ENTERING THE FORECAST AREA FROM MN ON
THE EASTERN PERIPHERY OF STEEPER LOW-MID-LEVEL LAPSE RATES UNDER THE
FILLING CLOSED LOW. RAP ANALYSIS SHOWING THIS AREA IN A ZONE OF VERY
WEAK BULK SHEAR...SO JUST EXPECTING MOSTLY SHOWER ACTIVITY WITH
ISOLATED THUNDER OUT OF THIS ACTIVITY. LOOK FOR THIS CONVECTION TO
CONTINUE MOVING INTO THE AREA THROUGH THE REMAINDER OF THIS
AFTERNOON AND INTO TONIGHT AS THE MID-LEVEL TROUGH AXIS MOVES EAST
ACROSS THE REGION. LOOK FOR THE SHOWERS TO DIMINISH AND SKIES TO
CLEAR FROM WEST TO EAST AFTER MIDNIGHT AS SUBSIDENCE/DRYING TAKES
PLACE BEHIND THE DEPARTING TROUGH.
A RIDGE OF HIGH PRESSURE WILL THEN BUILD INTO THE AREA ON SUNDAY FOR
A DRY/MOSTLY SUNNY DAY. DESPITE MOSTLY SUNNY SKIES...COLD AIR
ADVECTION ON NORTHWEST WINDS OF 10-20 MPH WILL YIELD HIGH
TEMPERATURES SOME 10 DEGREES BELOW NORMAL IN THE LOW/MID 60S.
HIGH PRESSURE WILL BE SITUATED OVERHEAD FOR A CLEAR/COOL/CALM SUNDAY
NIGHT. LOOK FOR LOWS RANGING FROM AROUND 40 DEGREES FOR AREAS
ALONG/NORTHEAST OF I-94...TO THE MID/UPPER 40S ELSEWHERE. GIVEN THE
NEARLY SATURATED GROUND AND THE FACT THE HIGH IS OVERHEAD FOR CALM
WINDS...WAS THINKING SOME FOG WOULD BE POSSIBLE. HOWEVER...BUFKIT
SOUNDINGS SHOWING THAT THERE WILL BE PLENTY OF DRYING DURING THE
DAYTIME SUNDAY AND THEN MAINTAIN AT LEAST A 3-5 DEGREE SPREAD
THROUGH THE OVERNIGHT HOURS. WILL THEREFORE LEAVE FOG MENTION
OUT...BUT MAY BE SOMETHING TO KEEP AN EYE ON.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 218 PM CDT SAT JUN 1 2013
LOOK FOR HIGH PRESSURE TO REMAIN IN CONTROL ACROSS THE AREA THROUGH
MONDAY FOR A CONTINUED DRY BREAK FROM THE SOGGY CONDITIONS OF LATE.
LATEST GFS/ECMWF IN FAIRLY GOOD AGREEMENT IN BRINGING A COUPLE WEAK
MID-LEVEL TROUGHS ACROSS THE NORTHERN PLAINS INTO OUR REGION TUESDAY
THROUGH SATURDAY. VERY LITTLE CAPE/INSTABILITY IS INDICATED BY THE
MODELS WHICH WOULD LEAD TO MAINLY SHOWER CHANCES WITH PERHAPS AN
ISOLATED THUNDERSTORM OR TWO. APPEARS THIS PERIOD WILL ALSO CONTINUE
TO BE MARKED BY COOLER THAN NORMAL TEMPERATURE WITH HIGHS GENERALLY
IN THE 60S TO LOWER 70S AND OVERNIGHT LOWS IN THE 50S.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1242 PM CDT SAT JUN 1 2013
SCATTERED SHOWERS ARE EXPECTED TO DEVELOP ACROSS THE REGION THIS
AFTERNOON WITH A MORE WIDESPREAD BAND OF SHOWERS COMING THROUGH
LATE THIS AFTERNOON AND EARLY THIS EVENING. CEILINGS ARE MAINLY
HIGH END MVFR OR LOW END VFR RIGHT NOW AND SHOULD STAY THAT WAY
UNTIL THE MORE WIDESPREAD RAIN COMES IN TOWARD EVENING. A FEW
THUNDERSTORMS ARE POSSIBLE THIS AFTERNOON...BUT COVERAGE IS
EXPECTED TO BE VERY ISOLATED THAT THE CHANCES OF A STORM HITTING A
TERMINAL IS LOW ENOUGH THAT IT IS NOT MENTIONED IN THE TAF. WINDS
WILL SHIFT AROUND TO THE NORTHWEST THIS EVENING WITH SOME LOW END
MVFR AND IFR CEILINGS EXPECTED SHORTLY AFTER THE WINDS SHIFT AND
PRECIPITATION MOVES THROUGH. THESE CONDITIONS WILL LIKELY LAST
OVERNIGHT BEFORE SOME MINOR IMPROVEMENTS OCCUR TOMORROW MORNING.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...DAS
LONG TERM...DAS
AVIATION...HALBACH
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1242 PM CDT SAT JUN 1 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 321 AM CDT SAT JUN 1 2013
WHAT REMAINS OF THE CONVECTION IS DIMINISHING SLOWLY ACROSS THE
CENTRAL PART OF THE FORECAST AREA. EXPECT THIS TREND TO CONTINUE
THROUGH THE REMAINDER OF THE NIGHT. THE 01.05Z HRRR EVEN SUGGESTS
THE AREA WILL BE CLEAR OF ANY RAIN BY 12Z AND MAY NEED TO START
THE MORNING THAT WAY. AS THE DAY PROGRESSES...THE SURFACE LOW OVER
SOUTH DAKOTA MOVES ACROSS MINNESOTA INTO NORTHERN WISCONSIN AS THE
UPPER LEVEL LOW BECOMES AN OPEN WAVE. THE SHORT WAVE TROUGH SEEN
ON WATER VAPOR SATELLITE OVER SOUTH DAKOTA AND NEBRASKA WILL MOVE
ACROSS THE AREA. THE 01.00Z NAM INDICATES THIS WAVE WILL PRODUCE
UP TO 12 PVU/S OF VORTICITY ADVECTION IN THE 500-300 MB LAYER
DURING THE AFTERNOON. THE AREA WILL GET INTO THE DEFORMATION ON
THE BACK SIDE OF THE SURFACE LOW WITH SOME WEAK FRONTOGENESIS
DEVELOPING IN THE 1000-850 MB LAYER ALONG WITH SOME WEAK UP GLIDE
ON THE 295K SURFACE. THIS IS EXPECTED TO BE ENOUGH TO GENERATE
SOME SCATTERED SHOWERS DURING THE AFTERNOON AND WITH BETWEEN 200
AND 400 J/KG OF ML CAPE SOME ISOLATED THUNDERSTORMS SHOULD ALSO
DEVELOP. AS TEMPERATURES ALOFT COOL WITH THE PASSAGE OF THE UPPER
LEVEL TROUGH...THE FREEZING LEVEL WILL ALSO COME DOWN AND IF ANY
OF THE THUNDERSTORMS CAN DEVELOP A GOOD CORE ALOFT...SOME HAIL
WILL BE POSSIBLE. AS THE SYSTEM THEN MOVES AWAY FROM THE AREA
TONIGHT AND WITH THE LOSS OF THE CAPE...EXPECT THE ACTIVITY TO DIE
DOWN DURING THE EVENING WITH THE SHOWERS ENDING COMPLETELY AFTER
MIDNIGHT.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 321 AM CDT SAT JUN 1 2013
RIDGING ALOFT WILL BRIEFLY BUILD OVER THE UPPER MIDWEST FOR SUNDAY
AND MONDAY AND WITH HIGH PRESSURE AT THE SURFACE...A COUPLE OF DRY
DAYS ARE ANTICIPATED. THIS RIDGING THEN MOVES OFF AS ANOTHER
CLOSED UPPER LEVEL LOW APPROACHES FROM THE NORTHWEST. THIS SYSTEM
LOOKS TO BE ANOTHER SLOW MOVING SYSTEM AND WILL KEEP RAIN CHANCES
IN FOR AN EXTENDED TIME FROM MONDAY NIGHT THROUGH FRIDAY. UNLIKE
THE PAST SYSTEM...THIS ONE IS NOT EXPECTED TO PRODUCE NEARLY AS
MUCH HEAVY RAIN. THE 01.00Z GFS INDICATES PRECIPITABLE WATERS WITH
THIS SYSTEM WILL PRIMARILY BE IN THE 1 TO 1.25 INCH RANGE INSTEAD
OF 1.5 INCHES OR HIGHER AS WITH THE RECENT SYSTEM. ALSO...THE
01.00Z ECMWF SUGGESTS THAT AS THE SHORT WAVE TROUGHS ROTATE AROUND
THE UPPER LEVEL LOW...THE BULK OF THE FORCING WILL ACTUALLY BE
NORTH OF THE AREA FROM CENTRAL MINNESOTA AND NORTHWEST WISCONSIN
ON TO THE NORTH. ALSO NOT EXPECTING A LOT OF THUNDER FROM THIS
SYSTEM. NEITHER THE ECMWF OR GFS SHOW HARDLY ANY CAPE OVER THE AREA
FROM THIS SYSTEM AND THUS CUT THE THUNDER PROBABILITIES BACK TO
JUST HAVE ISOLATED AT BEST.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1242 PM CDT SAT JUN 1 2013
SCATTERED SHOWERS ARE EXPECTED TO DEVELOP ACROSS THE REGION THIS
AFTERNOON WITH A MORE WIDESPREAD BAND OF SHOWERS COMING THROUGH
LATE THIS AFTERNOON AND EARLY THIS EVENING. CEILINGS ARE MAINLY
HIGH END MVFR OR LOW END VFR RIGHT NOW AND SHOULD STAY THAT WAY
UNTIL THE MORE WIDESPREAD RAIN COMES IN TOWARD EVENING. A FEW
THUNDERSTORMS ARE POSSIBLE THIS AFTERNOON...BUT COVERAGE IS
EXPECTED TO BE VERY ISOLATED THAT THE CHANCES OF A STORM HITTING A
TERMINAL IS LOW ENOUGH THAT IT IS NOT MENTIONED IN THE TAF. WINDS
WILL SHIFT AROUND TO THE NORTHWEST THIS EVENING WITH SOME LOW END
MVFR AND IFR CEILINGS EXPECTED SHORTLY AFTER THE WINDS SHIFT AND
PRECIPITATION MOVES THROUGH. THESE CONDITIONS WILL LIKELY LAST
OVERNIGHT BEFORE SOME MINOR IMPROVEMENTS OCCUR TOMORROW MORNING.
&&
.HYDROLOGY...
ISSUED AT 321 AM CDT SAT JUN 1 2013
THE RAINS FROM FRIDAY EVENING HAVE CAUSED SOME RESPONSE ON SOME
AREA RIVERS. RISES HAVE BEEN OCCURRING ON THE WHITEWATER
RIVER...CEDAR RIVER IN OSAGE AND THE ROOT RIVER. ENOUGH RAIN FELL
ACROSS PARTS OF SOUTHEAST MINNESOTA AND NORTHEAST IOWA FOR
ADDITIONAL WITHIN BANK RISES TO OCCUR. EARLIER RAINS ARE STILL
EXPECTED TO PUSH PARTS OF THE MISSISSIPPI...BLACK...TREMPEALEAU
AND UPPER IOWA RIVERS NEAR OR OVER FLOOD STAGE. FOR ADDITIONAL
DETAILS...SEE THE LATEST RIVER FLOOD STATEMENTS.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...04
LONG TERM...04
AVIATION...HALBACH
HYDROLOGY...04