Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 06/12/13
AREA FORECAST DISCUSSION
NWS TAUNTON MA
739 PM EDT TUE JUN 11 2013
.SYNOPSIS...
A WARM FRONT STALLED ACROSS THE SOUTHERN PART OF THE AREA WILL
RESULT IN SHOWERS AND THUNDERSTORMS THROUGH TONIGHT. A COASTAL
LOW WILL MOVE SOUTH OF THE REGION WITH WIDESPREAD RAIN THURSDAY
AFTERNOON INTO FRIDAY. HIGH PRESSURE WILL BRING DRY AND NEAR
SEASONABLE CONDITIONS FOR THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
730 PM UPDATE...SHOWERS AND A FEW THUNDERSTORMS ACROSS THE EAST
COAST OF NEW ENGLAND SHOULD MOVE OFFSHORE BY 10 PM. RAINFALL RATES
UP TO 1 INCH PER HOUR ARE POSSIBLE...AND COULD LEAD TO POOR-
DRAINAGE FLOODING OF URBAN AND POOR DRAINAGE AREAS. MAINLY BROUGHT
NEAR-TERM FORECAST IN LINE WITH OBSERVED TRENDS. HRRR HAD A VERY
GOOD HANDLE ON THIS TIMING.
TONIGHT...THE BULK OF THE SHOWERS AND STORMS WILL GRADUALLY COME TO
AN END AS LOW PRESSURE MOVES THROUGH NEW ENGLAND AND INTO THE GULF
OF MAINE. HOWEVER...A SHORTWAVE MOVING AROUND THE UPPER LEVEL LOW
WILL RESULT IN SHOWERS CONTINUING THROUGH THE NIGHT ACROSS THE
NORTHERN ZONES. EXPECT WIDESPREAD PATCHY FOG ACROSS MUCH OF THE AREA
WITH PLENTY OF MOISTURE IN THE REGION BOTH IN THE AIR AND ON THE
GROUND.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH WEDNESDAY NIGHT/...
WEDNESDAY...A COLD FRONT WILL MOVE THROUGH THE AREA AS THE LOW
PRESSURE MOVES INTO THE MARITIMES. THERE IS POTENTIAL FOR A FEW
SHOWERS AS THIS OCCURS BUT EXPECT THESE TO COME TO AN END BY THE
AFTERNOON. TEMPERATURES WILL BE A BIT COOLER BEHIND THE FRONT...
ESPECIALLY WITH DECENT CLOUD COVER TO START THE DAY. HIGH PRESSURE
BUILDS IN LATE IN THE DAY GIVING WAY TO CLEARER SKIES.
WEDNESDAY NIGHT...HIGH PRESSURE WILL BE THE DOMINANT FEATURE
OVERNIGHT AHEAD OF ANOTHER LOW PRESSURE SYSTEM APPROACHING THE AREA
FROM THE MIDWEST. EXPECT LOW TEMPERATURES TO DROP INTO THE MID 40S
TO LOW 50S WITH EXCELLENT RADIATIONAL COOLING.
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
HIGHLIGHTS...
* COASTAL SYSTEM SOUTH OF OUR REGION THURSDAY NIGHT INTO FRIDAY
* COOLER CONDITIONS THIS WEEK...WITH A SLIGHT WARM UP THIS WEEKEND
OVERVIEW AND MODEL PREFERENCES...
DECENT OVERALL AGREEMENT AMONGST THE 11/12Z GUIDANCE SUITE
MEMBERS. STILL SOME DIFFERENCES REGARDING SOME VERY IMPORTANT
DETAILS HOWEVER. BASED THIS FORECAST OFF THE MODEL CONSENSUS
SOLUTION TO MINIMIZE THE DETAIL DIFFERENCES UNTIL WE CAN GET
GREATER CONFIDENCE IN ONE SOLUTION OVER ANOTHER.
RATHER CHILLY PATTERN EXPECTED FOR MOST OF THIS WEEK. POTENT MID-
LEVEL SHORTWAVE SHOULD AMPLIFY A MID-LEVEL TROUGH OVER NEW ENGLAND
LATE THIS WEEK. THIS IN TURN SHOULD STEER A LOW PRESSURE SOUTH OF
OUR REGION THURSDAY NIGHT INTO FRIDAY. CANADIAN AND ECMWF
SOLUTIONS ARE SLOWER AND TRACK FARTHER SOUTH THAN THE REST OF THE
GUIDANCE WHICH IS FAIRLY WELL CLUSTERED. LEANED MORE TOWARD THE
GFS-LED CONSENSUS FOR NOW WITH THIS STORM. THE AXIS OF HEAVIEST
RAINFALL IS DIFFERENT...EVEN AMONGST MODELS WITH A SIMILAR TRACK.
DO NOT YET HAVE MUCH CONFIDENCE IN THOSE TYPES OF DETAILS.
DETAILS...
THURSDAY AND THURSDAY NIGHT...
A LOW PRESSURE MOVES EAST FROM THE LOWER GREAT LAKES DURING THIS
PERIOD. ABUNDANT MOISTURE SHOULD BE AVAILABLE. AS MENTIONED
BEFORE...STILL SOME QUESTIONS AS TO WHERE THE HEAVIEST RAIN WILL
FALL. HEAVY RAINFALL IS POSSIBLE...BUT NOT EXPECTING AMOUNTS QUITE
AS HIGH AS WHAT WE SAW LATE LAST WEEK. THIS SYSTEM LOOKS MORE LIKE
AN EARLY WINTER STORM ALOFT RATHER THAN A LOW MORE TYPICAL OF
JUNE. WIND ADVISORIES MAY BE NEEDED IF THERE IS ENOUGH MIXING...
MAINLY ACROSS THE COASTAL REGIONS AND HIGHER TERRAIN.
FRIDAY...
INITIAL LOW PRES SLIDES EAST OF THE REGION DURING THE MORNING
WITH A COLD FRONT FOLLOWING QUICKLY BEHIND. STILL HAVE MOISTURE IN
THE SOUNDING WITH THIS FRONTAL PASSAGE AND LAPSE RATES ARE
EXPECTED TO BE MODERATE AROUND 6C/KM. SO A SHOWER OR THUNDERSTORM
MAY LINGER WITH THIS FRONT INTO THE EVENING HOURS.
THIS WEEKEND INTO MONDAY...HIGH PRESSURE WILL ARRIVE OVER THE
REGION. WITH A MID-LEVEL CUTOFF LOW TO THE NORTH...NOT EXPECTING
THIS RIDGE TO BE QUITE AS STRONG. IT SHOULD BE ENOUGH FOR A PERIOD
OF DRY WEATHER THIS WEEKEND WITH TEMPERATURES STARTING ON THE
COOL SIDE BEFORE MODERATING BY SUNDAY.
TUESDAY...ANOTHER LOW PRESSURE SHOULD APPROACH SOUTHEAST CANADA
DURING THIS TIME. SOUTHERN NEW ENGLAND SHOULD BE IN THE WARM
SECTOR OF THIS SYSTEM WITH A CHANCE OF SHOWERS.
&&
.AVIATION /00Z WEDNESDAY THROUGH SUNDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
OVERVIEW...MODERATE CONFIDENCE THROUGH WEDNESDAY NIGHT.
WIDESPREAD IFR CONDITIONS CONTINUE THROUGH TONIGHT FOR MUCH OF THE
AREA. IFR CONDITIONS LIKELY TO CONTINUE UNTIL WED MORNING AS FOG
DEVELOPS. EXPECT QUICK IMPROVEMENT TO VFR WEDNESDAY MORNING AND
CONTINUING THROUGH WEDNESDAY NIGHT. MAY SEE SOME LINGERING SHOWERS
AND BRIEF MVFR CONDITIONS THROUGH THE MORNING AND THEN TAPERING
OFF IN THE AFTERNOON.
KBOS TERMINAL...MODERATE CONFIDENCE. DURATION OF IFR CIGS IN TAF
MAY BE HELD ONTO TOO LONG.
KBDL TERMINAL...MODERATE CONFIDENCE.
OUTLOOK...THURSDAY THROUGH SUNDAY...
MODERATE CONFIDENCE THROUGH PERIOD.
THURSDAY-FRIDAY...VFR INTO EARLY THURSDAY. A PERIOD OF IFR/MVFR
IN WIDESPREAD RAIN LATE DAY THU INTO EARLY FRI AS A LOW PRES
PASSES S OF THE REGION. A COLD FRONT BRINGS ISOLATED THUNDERSTORMS
POSSIBLY DURING FRI AFTERNOON.
SATURDAY AND SUNDAY...VFR.
&&
.MARINE...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
OVERALL HIGH CONFIDENCE.
5 TO 8 FOOT SEAS WILL GRADUALLY DIMINISH THROUGH WEDNESDAY AS HIGH
PRESSURE BUILDS OVER THE WATERS. SOUTHWESTERLY WINDS WILL GUST 25
TO 30 KNOTS BEFORE SHIFTING TO THE NORTHWEST AND DIMINISHING
WEDNESDAY AFTERNOON. MAY SEE AN OCCASIONAL GUST TO 35 KNOTS...PARTICULARLY
ON THE SOUTHERN WATERS WEDNESDAY MORNING. SMALL CRAFT ADVISORIES
CONTINUE FOR THE OUTER WATERS AS WELL AS RHODE ISLAND AND BLOCK
ISLAND SOUNDS. SHOWERS...AN ISOLATED THUNDERSTORM OR TWO...AND FOG
ARE ALL POSSIBLE TONIGHT...LIMITING VISIBILITIES AND RESULTING IN
GUSTY WINDS IN AND AROUND THESE STORMS.
OUTLOOK...THURSDAY THROUGH SUNDAY...
MODERATE CONFIDENCE THROUGH THE PERIOD.
THURSDAY INTO FRIDAY...EXPECTING WINDS AND SEAS TO BE BELOW SMALL
CRAFT ADVISORY CRITERIA AT THE START. AN APPROACHING COASTAL
STORM WILL INCREASE SEAS AND WINDS BY THURSDAY NIGHT INTO FRIDAY.
NORTHEASTERLY GALES ARE POSSIBLE THURSDAY NIGHT INTO EARLY FRIDAY
AS THIS LOW PASSES OVER THE SOUTHER WATERS. OTHERWISE EXPECT HIGH
END SMALL CRAFT ADVISORY CONDITIONS.
SATURDAY...LINGERING SMALL CRAFT ADVISORY SEAS AS WINDS DISSIPATE
THROUGH THE DAY.
SUNDAY...WINDS AND SEAS BELOW SMALL CRAFT ADVISORY CONDITIONS.
&&
.HYDROLOGY...
WE KEPT THE FLOOD WATCH GOING AS THERE IS STILL SOME HEAVY RAIN IN
SHOWERS AND ISOLATED THUNDERSTORMS THAT WILL MOVE THROUGH THIS
EVENING.
THE MAIN CONCERN IS FOR URBAN FLOODING...BUT SOME SMALLER STREAMS
ARE ALSO VULNERABLE TO FLOOD...ESPECIALLY THOSE IN RI AND SE MA
WHICH HAVE RECEIVED THE HEAVIEST RAINFALL SO FAR WITH AMOUNTS OF
ONE TO TWO INCHES.
A FLOOD WARNING CONTINUES FOR THE PAWTUXET RIVER AT CRANSTON
RI...WHERE MINOR FLOODING IS OCCURRING WITH A RISE TO 11 FEET
FORECAST /MODERATE FLOODING/ OVERNIGHT TONIGHT.
AREAL FLOOD WARNING CONTINUES FOR SW RI MAINLY FOR THE PAWCATUCK
RIVER WHICH WILL REMAIN ABOVE FLOOD STAGE.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...FLOOD WATCH UNTIL 8 PM EDT THIS EVENING FOR MAZ004>007-012>021-
026.
NH...NONE.
RI...FLOOD WATCH UNTIL 8 PM EDT THIS EVENING FOR RIZ001>007.
MARINE...SMALL CRAFT ADVISORY UNTIL 7 PM EDT WEDNESDAY FOR ANZ235-237.
SMALL CRAFT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR ANZ250.
SMALL CRAFT ADVISORY UNTIL 5 AM EDT THURSDAY FOR ANZ254>256.
&&
$$
SYNOPSIS...BELK/RLG
NEAR TERM...BELK/RLG
SHORT TERM...RLG
LONG TERM...BELK
AVIATION...BELK/RLG
MARINE...BELK/RLG
HYDROLOGY...
AREA FORECAST DISCUSSION
NWS ALBANY NY
405 PM EDT MON JUN 10 2013
.SYNOPSIS...
A LOW PRESSURE SYSTEM AND ITS ASSOCIATED FRONTAL BOUNDARIES WILL
APPROACH FROM THE OHIO VALLEY AND GREAT LAKES...AND MOVE ACROSS
OUR REGION THROUGH TUESDAY. THIS SYSTEM WILL BRING A WIDESPREAD
SOAKING RAINFALL. THE RAIN WILL BE HEAVY AT TIMES...ALONG WITH
POSSIBLE THUNDERSTORMS. DRIER WEATHER IS EXPECTED WEDNESDAY AND
WEDNESDAY NIGHT WITH WEAK HIGH PRESSURE BUILDING IN.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
THROUGH TONIGHT...EXPECT UNSETTLED WEATHER WITH RAINFALL HEAVY AT
TIMES ESPECIALLY THIS EVENING. LOW PRESSURE OVER THE OHIO VALLEY
AND CENTRAL GREAT LAKES LATE THIS AFTERNOON WILL LIFT AND OCCLUDED
FRONT IN OUR DIRECTION TONIGHT. THE TRIPLE POINT WITH THE WARM
FRONT AND TRAILING COLD FRONT IS EXPECTED TO PASS ACROSS THE
EXTREME SOUTHEAST CORNER OF OUR FA LATE TONIGHT. THIS SCENARIO
WILL RESULT IN SOME LOCALLY HEAVY RAINFALL ESPECIALLY THROUGH
SHORTLY AFTER MIDNIGHT. PWATS THIS EVENING RISE TO BETWEEN 1.75
AND 2 INCHES ALONG WITH STRONG LOW LEVEL MOISTURE CONVERGENCE.
RAINFALL AMOUNTS OF AN INCH TO LOCALLY OVER 2 INCHES CAN BE
EXPECTED THROUGH TONIGHT. WILL KEEP ISOLATED THUNDER IN THE
FORECAST AS WELL EVEN THOUGH SHOWALTER INDICES ONLY BRIEFLY NEAR
ZERO AND SBCAPES ONLY A FEW HUNDRED J/KG. EXPECT OVERNIGHT LOWS TO
BE IN THE MID 50S TO MID 60S.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH THURSDAY/...
ON TUESDAY...IT DOES NOT APPEAR THAT THERE WILL BE A GREAT DEAL
OF SURFACE HEATING AS EXTENSIVE CLOUD COVER IS EXPECTED DURING
MUCH OF THIS PERIOD. SBCAPES TUESDAY AFTERNOON BTWN 400 AND 800
J/KG. BETTER CHANCE FOR ELEVATED CONVECTION AS SECONDARY TROUGH
ASSOCIATED WITH ANOTHER WAVE OF LOW PRESSURE MOVING ACRS NRN NEW
YORK PASSES THROUGH OUR REGION. EXPECT MORE SHOWERS ALONG WITH
ISOLATED THUNDERSTORMS AND PCPN GENERALLY AN ADDITIONAL QUARTER TO
HALF INCH IN MOST AREAS WITH ISOLATED AMOUNTS UP TO AN INCH.
EXPECT HIGHS ON TUESDAY TO BE IN THE 60S TO MID 70S.
MORE RAIN IS EXPECTED TUESDAY NIGHT AS A THIRD TROUGH OF LOW
PRESSURE SWINGS THROUGH THE FA WITH THE RAIN EXPECTED TO TAPER OFF
LATE AT NIGHT. EXPECT LOWS TUESDAY NIGHT IN THE UPPER 50S TO LOWER
60S.
ON WEDNESDAY EXPECT A BREEZY DAY WITH STILL THE POSSIBILITY OF
SCATTERED SHOWERS ESPECIALLY ACRS NRN AREAS AS A STRONG VORT AXIS
CROSSES FA SWINGING ARND THE BASE OF THE H5 TROF. HIGHS ON
WEDNESDAY ARE EXPECTED TO BE IN THE UPPER 60S TO UPPER 70S WITH
READINGS ARND 80 NEAR KPOU.
WEDNESDAY NIGHT AND THURSDAY THE FORECAST WILL HINGE ON HOW FAR
NORTH THE RAINFALL SHIELD ASSOCIATED WITH A SYSTEM PASSING TO OUR
SOUTHEAST GETS TO OUR AREA. AT THIS TIME WILL FORECAST CHANCE POPS
ACRS THE SRN HALF OF THE FA. EXPECT LOWS WEDNESDAY NIGHT IN THE
UPPER 40S TO LOWER 50S WITH HIGHS ON THURSDAY IN THE UPPER 60S TO
MID 70S.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
THE LONG TERM STARTS OUT A BIT UNSETTLED...BUT THINGS IMPROVE FOR
THE UPCOMING WEEKEND. THE GFS/ECMWF/GEFS MEAN/CANADIAN GGEM/HPC
GUIDANCE ALL INDICATE A CYCLONE WILL MOVE FROM THE OHIO VALLEY INTO
THE MID ATLANTIC REGION ON THU-THU NIGHT. THE SFC CYCLONE IS
ASSOCIATED WITH A PROGRESSIVE POSITIVELY TILTED LONG WAVE TROUGH.
AN INVERTED SFC TROUGH EXTENDING N/NE OF THE SFC CYCLONE WILL
PRODUCE SOME SHOWERS AS FAR NORTH AS THE INTERSTATE 90 CORRIDOR THU
PM. THERE WILL LIKELY BE A SHARP CUT-OFF IN THE OVER RUNNING
RAINFALL. THE NRN ZONES MAY STAY DRY. FOR NOW...SLIGHT CHC POPS
ARE IN THE FORECAST FOR THU NIGHT NORTH OF THE MID HUDSON
VALLEY...SE CATSKILLS...AND NW CT. CHC POPS ARE KEPT FURTHER SOUTH
AND EAST. THE ECMWF TRIES TO KEEP THE STEADY SHOWERS GOING THU
NIGHT. THE SYSTEM LOOKS PROGRESSIVE ENOUGH TO NOT PLACE HIGHER POPS
AT THIS TIME. LOWS WILL BE IN THE M40S TO NEAR 50F OVER THE HIGHER
TERRAIN...AND LOWER TO M50S IN THE VALLEYS AND OVER TH HILLS.
FRI-FRI NIGHT...A COLD FRONT DROPS SOUTH AND EAST FROM THE ST
LAWRENCE RIVER VALLEY. THE GFS HAS SBCAPES OF 250-500 J/KG WITH
TOTAL TOTALS OF AROUND 50. THE 850-500 HPA LAPSE RATES APPROACH 6.5
C/KM. SOME SHOWERS WITH ISOLD THUNDERSTORMS WILL BE POSSIBLE WITH
THE FRONTAL PASSAGE. THE BETTER UPPER LEVEL DYNAMICS ARE DISPLACED
TO THE NORTH...AND THE LOW-LEVEL MOISTURE IS LIMITED WITH SFC DEWPTS
IN THE M40S TO M50S. H850 TEMPS WILL BE AROUND +10C...SO MAX TEMPS
WILL BE SEASONABLE IN 70-75F RANGE IN THE VALLEYS AND NW CT...AND
MID AND U60S OVER THE MTNS. WEAK COLD ADVECTION WILL OCCUR IN THE
WAKE OF THE FRONT WITH HIGH PRESSURE BUILDING IN FROM SRN ONTARIO
AND THE GREAT LAKES REGION. H850 TEMPS FALL TO +6C TO +9C. LOWS
WILL RANGE FROM THE M40S TO M50S OVER THE FCST AREA.
SATURDAY-SUNDAY...A LARGE DOME OF SFC HIGH PRESSURE WILL BE IN
CONTROL OVER THE NORTHEAST AND THE MID ATLANTIC REGION. THE HIGH
WILL RIDGE IN FROM THE CAROLINAS WITH A RETURN FLOW OF MILDER AIR.
THE REGION WILL ENJOY PLENTY OF SUNSHINE WITH NEAR NORMAL TEMPS ON
SAT...AND SLIGHTLY ABOVE NORMAL TEMPS FOR SUNDAY.
SUNDAY NIGHT INTO MONDAY...A QUICK MOVING LOW PRESSURE SYSTEM WITH
ITS ASSOCIATED FRONTAL BOUNDARIES WILL APPROACH FROM THE GREAT LAKES
REGION IN THE NEAR ZONAL FLOW ALOFT. THE BEST CHC OF SHOWERS LOOKS
LIKE MONDAY BASED ON THE CONSENSUS FROM THE MEDIUM RANGE GUIDANCE.
THERE COULD BE SOME THUNDERSTORMS TOO...BUT BASED ON THE TIMING OF
THE DISTURBANCE THEY HAVE NOT BEEN ADDED TO GRIDDED FCST YET.
OVERALL...TEMPS WILL BE NEAR NORMAL WITH PCPN SLIGHT BELOW NORMAL
FOR THE STRETCH.
&&
.AVIATION /20Z MONDAY THROUGH SATURDAY/...
A STEADY RAIN HAS DEVELOPED ACROSS EASTERN NY AND WESTERN NEW
ENGLAND AHEAD OF AN APPROACHING WARM FRONT. MOST OF THE RAINFALL
HAS BEEN RATHER LIGHT SO FAR...WHICH HAS KEPT FLYING CONDITIONS
GENERALLY VFR. BASED ON UPSTREAM OBS AND THE 3KM HRRR MODEL...AS THE
AFTERNOON GOES ON...FLYING CONDITIONS WILL GRADUALLY DECREASE TO
MVFR. THIS WILL BE DUE TO THE RAIN PICKING UP IN INTENSITY AND
ALLOWING VSBYS TO DROP...ESP FOR THE SOUTHERN TERMINALS OF
KPSF/KPOU. IT MAY TAKE UNTIL AFTER 00Z UNTIL KALB/KGFL SEE IFR
CONDITIONS.
A MODERATE STEADY RAIN IS EXPECTED AT ALL TERMINALS FOR THE LATE
EVENING INTO THE FIRST HALF OF THE OVERNIGHT. THIS
RAINFALL...ALONG WITH A PERSISTENT SOUTHERLY FLOW...SHOULD ALLOW
FOR IFR CONDITIONS AT ALL SITES. LATE TONIGHT...THE STEADY RAIN
WILL TAPER OFF...ALLOWING FOR IMPROVEMENT IN THE VSBYS...ALTHOUGH
THERE WILL BE PLENTY OF LINGERING LOW LEVEL MOISTURE WHICH WILL
KEEP SOME LOW STRATUS CLOUDS AROUND. BY THE MID MORNING HOURS ON
TUESDAY...MOST OF THESE LOW CLOUDS SHOULD START TO BREAK
UP...ALTHOUGH THERE STILL MAY BE SOME LINGERING SHOWERS AROUND.
SFC WINDS ARE NEARLY CALM OR LIGHT OUT OF THE E-SE EARLY THIS AFTN.
EVENTUALLY BY LATE IN THE DAY...WINDS WILL BE OUT OF THE SOUTH AROUND
5-10 KTS. WINDS WILL SWITCH TO A W-SW DIRECTION ON TUESDAY AT
SIMILAR SPEEDS.
OUTLOOK...
TUE PM-TUE NIGHT...VFR/MVFR. CHC -SHRA/TSRA
WED...VFR...NO SIG WX.
THU...VFR/MVFR. CHC -SHRA/TSRA AT KPOU.
FRI...VFR. NO SIG WX.
&&
.FIRE WEATHER...
WET WEATHER IS EXPECTED THROUGH TUESDAY NIGHT. RAINFALL AMOUNTS
ARE EXPECTED TO RANGE FROM 1 TO 3 INCHES WITH THE HEAVIEST
RAINFALL EXPECTED THIS EVENING.
&&
.HYDROLOGY...
MODERATE TO HEAVY RAIN IS EXPECTED WITH THE CURRENT RAINFALL EVENT
THROUGH TUESDAY NIGHT.
THROUGH TUESDAY NIGHT A LOW PRESSURE SYSTEM WITH A OCCLUDED FRONT
IS EXPECTED TO CROSS OUR REGION. AT THIS TIME RAINFALL AMOUNTS
LOOK TO BE QUITE HEAVY WITH 1 TO 3 INCHES OF RAIN EXPECTED WITH
LOCALIZED HIGHER AMOUNTS. THE HEAVIEST RAIN APPEARS AS THOUGH IT
WILL BE ACROSS SOUTHERN VERMONT...THE NORTHERN TACONICS AND THE
BERKSHIRES WITH A SECONDARY AXIS OF HEAVY PCPN ACRS THE ERN
CATSKILLS. THE HOUSATONIC BASIN WILL ALSO BE IMPACTED WITH THE
POTENTIAL FOR MINOR FLOODING ALONG THE CONNECTICUT SECTION OF THE
RIVER. A FLOOD WATCH REMAINS IN EFFECT FOR BERKSHIRE AND
LITCHFIELD COUNTIES. AFTER A BRIEF LULL IN THE PRECIPITATION
DURING MID WEEK...MORE RAIN IS POSSIBLE BY THURSDAY AS A LOW
PRESSURE SYSTEM PASSING SOUTHEAST OF OUR REGION OFF THE SOUTHERN
NEW ENGLAND COAST.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED
AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE
ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...FLOOD WATCH THROUGH LATE TUESDAY NIGHT FOR CTZ001-013.
NY...NONE.
MA...FLOOD WATCH THROUGH LATE TUESDAY NIGHT FOR MAZ001-025.
VT...NONE.
&&
$$
SYNOPSIS...11/JPV
NEAR TERM...11
SHORT TERM...11
LONG TERM...WASULA
AVIATION...FRUGIS
FIRE WEATHER...11
HYDROLOGY...11
AREA FORECAST DISCUSSION
NWS ALBANY NY
126 PM EDT MON JUN 10 2013
.SYNOPSIS...
A LOW PRESSURE SYSTEM AND ITS ASSOCIATED FRONTAL BOUNDARIES WILL
APPROACH FROM THE OHIO VALLEY AND GREAT LAKES...AND MOVE ACROSS OUR
REGION THIS AFTERNOON THROUGH TUESDAY. THIS SYSTEM WILL BRING A
WIDESPREAD SOAKING RAINFALL. THE RAIN WILL BE HEAVY AT
TIMES...ALONG WITH POSSIBLE THUNDERSTORMS. MAINLY DRY WEATHER IS
EXPECTED WEDNESDAY INTO THURSDAY WITH WEAK HIGH PRESSURE BUILDING
IN.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1215 PM EDT...ANOTHER WIDESPREAD SOAKING RAINFALL WILL
IMPACT THE REGION THROUGH THE DAY TOMORROW. THERE IS THE POTENTIAL
FOR FLOODING...MAINLY FOR BERKSHIRE/LITCHFIELD COUNTIES WHERE A
FLOOD WATCH HAS BEEN ISSUED. REFER TO HYDROLOGY SECTION FOR
DETAILS.
THE LATEST MOSAIC RADAR SHOWS THE LEADING EDGE OF THE RAINFALL
ALREADY REACHING THE MOHAWK VALLEY....SARATOGA REGION AND EXTREME
SOUTHWEST VERMONT WITH STEADY RAIN ACROSS THE CAPITAL REGION...MID
HUDSON VALLEY...EASTERN CATSKILLS...BERKSHIRES AND NW CT. WE HAVE
SPED UP THE ARRIVAL TIME FOR RAIN ACROSS THE AREA TO ACCOUNT FOR
THESE TRENDS.
IN ADDITION...WITH THE QUICKER ARRIVAL OF RAIN...TEMPS WON/T HAVE
A CHANCE TO RISE AS MUCH AS ANTICIPATED TODAY. MAX TEMPS WILL
LIKELY BE IN THE 60S LATE THIS MORNING...AS RAINFALL WILL KEEP
TEMPS FROM RISING...AND THEY MAY EVEN FALL A DEGREE OR TWO AS
TEMPS WET BULB.
THE HEAVIEST RAIN IS EXPECTED TO FALL FROM LATE THIS AFTERNOON OR
THIS EVENING THROUGH EARLY TUESDAY MORNING...AS A STRENGTHENING LOW
LEVEL JET SEGMENT MOVES ACROSS THE AREA AND DEEP LAYER MOISTURE
INCREASES COINCIDENT WITH THE STRONGEST FORCING. 850MB SOUTHERLY
WIND ANOMALIES OF +3 TO +4 STDEV AND PRECIPITABLE WATER ANOMALIES OF
+2 TO +3 STDEV ARE FORECAST FROM THE GEFS. SOME EMBEDDED CONVECTIVE
ELEMENTS ARE POSSIBLE...WHICH COULD LOCALLY ENHANCE RAINFALL
AMOUNTS. THIS IS MAINLY DUE TO SOME ELEVATED INSTABILITY AND SURFACE
BASED CAPE WILL BE MINIMAL WITH OUR AREA POSITIONED NORTH OF THE
ADVANCING WARM FRONT. SO WILL MENTION ISOLATED THUNDER...BUT THE
MAIN THREAT WILL BE HEAVY RAIN. VARIOUS SOURCES OF MODEL GUIDANCE IN
GENERALLY GOOD AGREEMENT WITH MAIN SYNOPTIC FEATURES THROUGH TONIGHT.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
IT APPEARS MUCH OF THE STEADY AND HEAVIER RAIN WILL BE EXITING THE
AREA BY TUESDAY MORNING...AS THE WARM FRONT AND A POSSIBLE WEAK WAVE
DEVELOPING ALONG IT SHIFT INTO EASTERN NEW ENGLAND. HOWEVER...THIS
WILL NOT SIGNIFY THE END OF OUR RAINFALL AS THE UPPER LEVEL TROUGH
AXIS AND SURFACE OCCLUDED FRONT STILL HAVE THE PASS THROUGH DURING
THE DAY. SO WILL CONTINUE TO MENTION LIKELY TO CATEGORICAL POPS
THROUGH THE DAY ASSOCIATED WITH SHOWERS.
SOME DIVERGENCE IN MODEL SOLUTIONS DO START TO OCCUR MAINLY WITH THE
POSITION/TRACK OF THE MAIN SURFACE LOW...WHICH WILL TRACK RIGHT OVER
OUR AREA OR AT LEAST THE NORTHERN HALF OF THE AREA. THIS WILL HAVE
TO BE WATCHED CAREFULLY...SINCE IF A MORE NORTHERN TRACK OCCURS THIS
COULD POTENTIALLY PUT AT LEAST THE SOUTHERN HALF OF THE AREA UNDER A
THREAT FOR MORE ROBUST CONVECTION IF ENOUGH HEATING CAN TAKE PLACE.
THIS SCENARIO IS HIGHLY SPECULATIVE AT THIS TIME...SINCE MUCH OF THE
AREA COULD REMAIN SOCKED IN WITH CLOUDS AND THUS NOT ALLOWING FOR
HEATING. WITH THE VIGOROUS UPPER TROUGH AXIS PASSING THROUGH...MID
LEVEL LAPSE RATES EXPECTED TO STEEPEN ENOUGH TO AT LEAST WARRANT
MENTION OF CHANCE THUNDER. AGAIN...THE THREAT FOR STRONGER
CONVECTION IS QUITE MUDDLED AT THIS TIME.
SHOWERS SHOULD START TO TAPER OFF SOMEWHAT TUESDAY NIGHT...AS THE
UPPER TROUGH AXIS SHIFTS EAST OF THE AREA. HOWEVER WITH ONE OR MORE
SHORT WAVES EMBEDDED IN THE DEVELOPING NORTHWEST FLOW ALOFT FORECAST
TO PASS THROUGH...SCATTERED SHOWERS WILL STILL BE POSSIBLE LATE
TUESDAY NIGHT THROUGH WEDNESDAY. AT LEAST PARTIAL SUNSHINE IS
EXPECTED ON WEDNESDAY...AS MIXING BECOMES MORE FAVORABLE IN THE
LOWER-MID TROPOSPHERE. THE INCREASED MIXING WILL ALSO RESULT IN
BREEZY CONDITIONS FROM LATE MORNING INTO EARLY EVENING.
ANY SHOWERS SHOULD TEND TO DIMINISH WEDNESDAY NIGHT AS WEAK HIGH
PRESSURE BUILDS INTO THE REGION FROM THE GREAT LAKES.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
CHAOTIC UPPER FLOW SHOULD PREVAIL THURSDAY AND FRIDAY AS ONE UPPER
IMPULSE TRACKS JUST SOUTH OF OUR REGION THURSDAY...THEN ANOTHER
SYSTEM TRACKS THROUGH NORTHERN AND EASTERN AREAS FRIDAY. MOST OF
THE MOISTURE...INSTABILITY AND UPPER DYNAMICS IN THE SYSTEM THURSDAY
SHOULD TRACK SOUTH OF OUR REGION...ALTHOUGH SOME SCATTERED SHOWERS
ARE POSSIBLE IN THE EASTERN CATSKILLS...MID HUDSON VALLEY AND NW CT.
ON FRIDAY...AN AXIS OF INSTABILITY WITHIN NORTHWEST FLOW SHOULD
RESULT ISOLATED TO SCATTERED THUNDERSTORMS. AS THE FRIDAY SYSTEM
EXITS...THERE SHOULD BE A BRIEF SHOT OF COOLER AIR.
HIGHS THURSDAY WITH PERIODS CLOUDS AND SUN...MOSTLY CLOUDY IN SOME
AREAS...SHOULD BE IN THE LOWER TO MID 70S...AND AS USUAL COOLER IN
HIGHER ELEVATIONS DURING THE ENTIRE PERIOD THURSDAY THROUGH SUNDAY.
HIGHS FRIDAY...WITH POTENTIALLY MORE SUN BEFORE THE ISOLATED TO
SCATTERED THUNDERSTORMS...SHOULD BE IN THE UPPER 70S TO NEAR 80.
BROAD FLAT UPPER RIDGE AXIS BEGINS TO BUILD INTO THE REGION BY
SATURDAY WITH A LITTLE BIT OF WARM ADVECTION. THERE SHOULD BE MORE
SUN THAN CLOUDS IN MOST AREAS WITH HIGHS IN THE MID TO UPPER 70S.
SOME HINTS A ANOTHER QUICK MOVING SMALL UPPER IMPULSE APPROACHING
FOR SUNDAY WITH SOME ISOLATED TO SCATTERED SHOWER AND THUNDERSTORM
ACTIVITY LATE IN THE DAY SUNDAY. THE TIMING AND EXTEND OF ANY
SHOWERS AND THUNDERSTORMS CAN BE DETERMINED AS THE EVENT GETS
CLOSER. HIGHS SUNDAY IN THE UPPER 70S TO LOWER 80S.
&&
.AVIATION /18Z MONDAY THROUGH FRIDAY/...
A STEADY RAIN HAS DEVELOPED ACROSS EASTERN NY AND WESTERN NEW
ENGLAND AHEAD OF AN APPROACHING WARM FRONT. MOST OF THE RAINFALL
HAS BEEN RATHER LIGHT SO FAR...WHICH HAS KEPT FLYING CONDITIONS
GENERALLY VFR. BASED ON UPSTREAM OBS AND THE 3KM HRRR MODEL...AS THE
AFTERNOON GOES ON...FLYING CONDITIONS WILL GRADUALLY DECREASE TO
MVFR. THIS WILL BE DUE TO THE RAIN PICKING UP IN INTENSITY AND
ALLOWING VSBYS TO DROP...ESP FOR THE SOUTHERN TERMINALS OF
KPSF/KPOU. IT MAY TAKE UNTIL AFTER 00Z UNTIL KALB/KGFL SEE IFR
CONDITIONS.
A MODERATE STEADY RAIN IS EXPECTED AT ALL TERMINALS FOR THE LATE
EVENING INTO THE FIRST HALF OF THE OVERNIGHT. THIS
RAINFALL...ALONG WITH A PERSISTENT SOUTHERLY FLOW...SHOULD ALLOW
FOR IFR CONDITIONS AT ALL SITES. LATE TONIGHT...THE STEADY RAIN
WILL TAPER OFF...ALLOWING FOR IMPROVEMENT IN THE VSBYS...ALTHOUGH
THERE WILL BE PLENTY OF LINGERING LOW LEVEL MOISTURE WHICH WILL
KEEP SOME LOW STRATUS CLOUDS AROUND. BY THE MID MORNING HOURS ON
TUESDAY...MOST OF THESE LOW CLOUDS SHOULD START TO BREAK
UP...ALTHOUGH THERE STILL MAY BE SOME LINGERING SHOWERS AROUND.
SFC WINDS ARE NEARLY CALM OR LIGHT OUT OF THE E-SE EARLY THIS AFTN.
EVENTUALLY BY LATE IN THE DAY...WINDS WILL BE OUT OF THE SOUTH AROUND
5-10 KTS. WINDS WILL SWITCH TO A W-SW DIRECTION ON TUESDAY AT
SIMILAR SPEEDS.
OUTLOOK...
TUE PM-TUE NIGHT...VFR/MVFR. CHC -SHRA/TSRA
WED...VFR...NO SIG WX.
THU...VFR/MVFR. CHC -SHRA/TSRA AT KPOU.
FRI...VFR. NO SIG WX.
&&
.FIRE WEATHER...
NO FIRE WEATHER RELATED CONCERNS EXPECTED FOR AT LEAST THE NEXT
SEVERAL DAYS. ANOTHER WIDESPREAD SOAKING RAINFALL IS IN STORE TODAY
THROUGH TUESDAY ACROSS THE REGION...BRINGING AT LEAST 1 TO 2 INCHES
OF RAIN AND POSSIBLY MORE.
&&
.HYDROLOGY...
MORE HEAVY RAIN IN STORE FROM THIS AFTERNOON THROUGH TUESDAY...WHICH
MAY RESULT IN SOME FLOODING ESPECIALLY FOR THE BERKSHIRES AND
LITCHFIELD HILLS.
A LOW PRESSURE SYSTEM AND ITS ASSOCIATED FRONTAL BOUNDARIES WILL
SLOWLY CROSS OUR REGION THROUGH TUESDAY. AT THIS TIME IT STILL LOOKS
LIKE RAINFALL AMOUNTS WILL BE 1 TO 3 INCHES WITH THE HIGHEST AMOUNTS
ACROSS WESTERN NEW ENGLAND. THE HOUSATONIC BASIN WILL ESPECIALLY BE
SUSCEPTIBLE TO MINOR FLOODING DUE TO THE COMBINATION OF ALREADY
ELEVATED RIVER LEVELS AND HEAVY RAINFALL. THEREFORE A FLOOD WATCH
HAS BEEN ISSUED FOR THIS AREA.
WILL HOLD OFF ON ANY FLOOD WATCHES FOR THE REST OF THE AREA FOR NOW
SINCE EXPECTED QPF IS LOWER OUTSIDE OF WESTERN NEW ENGLAND AND RIVER
LEVELS ARE SOMEWHAT LOWER. WILL CONTINUE MENTION OF THE HEAVY
RAINFALL POTENTIAL IN THE HWO...WITH THE POSSIBILITY OF SMALL STREAM
AND URBAN/POOR DRAINAGE FLOODING. THE HEAVIEST RAIN LOOKS TO FALL
FROM THIS EVENING INTO EARLY TUESDAY MORNING.
DRYING CONDITIONS ARE EXPECTED FOR WEDNESDAY INTO THURSDAY.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED
AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE
ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...FLOOD WATCH FROM 6 PM EDT THIS EVENING THROUGH LATE TUESDAY
NIGHT FOR CTZ001-013.
NY...NONE.
MA...FLOOD WATCH FROM 6 PM EDT THIS EVENING THROUGH LATE TUESDAY
NIGHT FOR MAZ001-025.
VT...NONE.
&&
$$
SYNOPSIS...FRUGIS/JPV
NEAR TERM...FRUGIS/11/JPV
SHORT TERM...JPV
LONG TERM...NAS
AVIATION...FRUGIS
FIRE WEATHER...JPV
HYDROLOGY...11/JPV
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1031 PM CDT TUE JUN 11 2013
.DISCUSSION...
834 PM CDT
A FEW THOUGHTS REGARDING THE THUNDERSTORM THREAT OVERNIGHT AND THE
MODERATE RISK FOR SEVERE WEATHER WEDNESDAY...
THIS EVENING...A WARM FRONT EXTENDS FROM WESTERN IOWA EAST TOWARDS
IOWA CITY...THEN LOSES ITS DEFINITION SOUTHEAST INTO CENTRAL
ILLINOIS. LOW TO MID 70 DEW POINTS ARE POOLING ALONG THE BOUNDARY
TO OUR WEST...BUT AS A 20Z SOUNDING OUT OF DVN SHOWED...A STRONG
CAP IS IN PLACE WITH 825MB TEMPS AROUND 21C. LATEST RAP GUIDANCE
INDICATES THE THE CAP WILL REMAIN IN PLACE THROUGH THE REMAINDER
OF THE EVENING AND TONIGHT. WITH THAT SAID....THE THREAT FOR
SEVERE WEATHER THROUGH THE REMAINDER OF TODAY HAS GREATLY
DIMINISHED. FOCUS TURNS OUT TO THE WEST TONIGHT WHERE A 50-60KT
LOW LEVEL JET IS EXPECTED TO DEVELOP WITH THE BEST MOISTURE
CONVERGENCE FOCUSED OVER CENTRAL NEBRASKA...AND BY MIDNIGHT
TONIGHT SLIGHTLY FARTHER EAST OVER THE MID MISSOURI VALLEY.
DESPITE THE FOCUS BEING WELL OFF TO OUR WEST...THERE IS SOME
ASCENT ALONG THE WARM FRONT SO CAN NOT RULE OUT SOMETHING TRYING
TO DEVELOP THIS EVENING NORTH OF THE WARM FRONT AND MOVING INTO
NORTHERN ILLINOIS...BUT EXPECT COVERAGE TO BE LOW AWAY FROM THE
BETTER FORCING WITH THE LLJ. WITH THAT IN MIND...LOWERED POPS
ACROSS MUCH OF THE CWA FOR THE OVERNIGHT HOURS AND FEEL THEY MAY
STILL BE ON THE HIGH END. CONVECTIVE ALLOWING MODELS STILL SHOW
AN MCS DEVELOPING AT THE NOSE OF THE LLJ TONIGHT...AND BY
DAYBREAK TOMORROW POSSIBLY MOVING INTO NORTHWESTERN ILLINOIS...
BUT MORE LIKELY STAYING NORTH OF THE STATE LINE. EITHER WAY...LLJ
IS VEERING AND WEAKENING BY THAT TIME SO CONVECTION SHOULD BE IN
A WEAKENING PHASE.
THE STORM PREDICTION CENTER CONTINUES TO CARRY US UNDER A MODERATE
RISK WEDNESDAY AND THIS SEEMS TO BE ON TRACK. APPEARS WE WILL BE
UNDER A PRETTY DYNAMIC ENVIRONMENT TOMORROW AS A COUPLED JET SETS
UP WITH THE BEST UPPER LEVEL DIVERGENCE OVER CENTRAL AND NORTHERN
ILLINOIS. MODERATE HEIGHT FALLS ASSOCIATED WITH THE MID LEVEL WAVE
MOVING INTO THE AREA LATE AFTERNOON/EARLY EVENING TOMORROW WILL
PROVIDE LARGE SCALE ASCENT ACROSS THE AREA TO HELP WEAKEN THE CAP.
THE SURFACE LOW TRACKS EAST ACROSS THE MISSISSIPPI VALLEY JUST
SOUTH OF MLI...THOUGH THERE ARE SOME MODELS SUGGESTING THE LOW
TRACK AND RESULTING SEVERE THREAT MAY TRACK SLIGHTLY FARTHER
NORTH. SOME MODELS ALSO INDICATE THE LOW DEEPENING SLIGHTLY
TOMORROW AFTERNOON WITH 2-4MB PRESSURE FALLS OVERSPREADING AREAS
SOUTH OF I-80. THIS WILL ONLY HELP TO ENHANCE WHAT ALREADY LOOKS
TO BE PRETTY STRONG LOW LEVEL HELICITY TOMORROW. DEEP LAYER SHEAR
TOMORROW IS ALSO FORECAST TO BE QUITE STRONG. ALL SAID THERE IS
CONCERN FOR DISCRETE SUPER CELLS DEVELOPING IN THE AFTERNOON WITH
THE WHOLE GAMUT OF SEVERE WEATHER POSSIBLE...LARGE HAIL...
DAMAGING WINDS AND QUITE POSSIBLY TORNADOES. STORMS SHOULD
EVENTUALLY CONGEAL INTO A LINE WITH THE MAIN THREAT TURNING
BECOMING DAMAGING WINDS...THOUGH QLCS TORNADOES WILL STILL BE A
CONCERN. HOW QUICKLY WE TRANSITION FROM DISCRETE SUPER CELLS TO A
LINEAR MCS IS UNCERTAIN. INTERESTING TO NOTE THAT ONE OF THE TOP
CIPS ANALOGS IS JUNE 05 2010 WHICH DID HAVE DISCRETE SUPER CELLS
WITH TORNADOES LATER INTO THE EVENING.
DEUBELBEISS
//PREV DISCUSSION...
300 PM CDT
MAIN FORECAST CONCERNS/CHALLENGES IN THE NEAR TERM ARE WITH
MULTIPLE ROUNDS OF CONVECTION POSSIBLE ACROSS THE ENTIRE CWA
TONIGHT THROUGH WEDNESDAY NIGHT WITH SEVERE WEATHER NOT OUT OF
THE QUESTION THIS EVENING AND OVERNIGHT...BUT WITH A MORE
SIGNIFICANT SEVERE WEATHER OUTBREAK BECOMING INCREASINGLY MORE
POSSIBLE ACROSS A PORTION OF THE CWA ON WEDNESDAY.
IN THE NEAR TERM...CONTINUE TO MONITOR CONVECTION DEVELOPING JUST
SOUTHWEST/SOUTH OF THE CWA AT THIS TIME AS A MID LEVEL IMPULSE
SLIDES EAST ACROSS THE AREA AND ENCOUNTERS SOME WEAK LOW/MID
LEVEL CONVERGENCE IN AND AROUND SHIFTING SURFACE TROUGH ACROSS
IOWA. THIS AREA OF CONVECTION SHOULD CONTINUE EAST/SOUTHEAST WITH
TIME FOR THE REMAINDER OF THE AFTERNOON MAINLY ONLY AFFECTING
AREAS FROM LA SALLE IN ILLINOIS SOUTHEAST TO RENSSELAER IN
INDIANA...SUPPORTED BY THIS WAVE AND CURRENT WAA IN PLACE.
ALTHOUGH INSTABILITY REMAINS RATHER WEAK ACROSS THESE AREAS AS
WELL AS CIN IN PLACE...LATEST TRENDS SUPPORT A NORTHEASTWARD
EXPANSION OF THE INSTABILITY AXIS AS WELL AS WEAKENING CIN.
DESPITE WEAKLY FORCED...THESE CONDITIONS COINCIDING WITH
SUFFICIENT BULK SHEAR COULD SUPPORT AN ISOLATED HAIL/WIND THREAT
THROUGH LATE AFTERNOON. GOING INTO THE EARLY EVENING...COULD SEE
A DRY PERIOD FOR MOST OF NORTHERN ILLINOIS AND NORTHWEST INDIANA
BUT WITH THE POSSIBILITY FOR AN INCREASE IN COVERAGE OF
THUNDERSTORMS ONCE AGAIN LATER IN THE EVENING. THIS IS A DEFINITE
POSSIBILITY ESPECIALLY AS SEVERAL MID LEVEL FEATURES/SPEED MAXES
ARE ANTICIPATED TO ROUND THE MID LEVEL RIDGE...AS WELL AS A
VEERING LLJ STRENGTHENS THIS EVENING.
CONTINUE TO MONITOR THESE MID LEVEL FEATURES TRACKING EAST ACROSS
THE CENTRAL AND NORTHERN PLAINS ON LATEST VISIBLE
SATELLITE...TRYING TO GRAB A HANDLE ON THIS POSSIBILITY OF
INCREASED CHANCES FOR CONVECTION LATER THIS EVENING. THIS IS DUE
TO MOST GUIDANCE VARYING TO SOME DEGREE ON PLACEMENT AS WELL AS
TIMING THIS EVENING...WITH CONFIDENCE NOT THE GREATEST FOR
CONVECTIVE EVOLUTION THIS EVENING. ALTHOUGH LATEST THOUGHTS FOR
THIS EVENING ONCE AGAIN DO INCLUDE THE POSSIBILITY FOR AN
INCREASED CHANCE FOR THUNDERSTORMS AS WELL AS THE POSSIBILITY FOR
SEVERE WEATHER...DAMAGING WINDS AND HAIL ONCE AGAIN THE MAIN
THREATS. MID LEVEL FEATURE MOVING OUT OF THE CENTRAL PLAINS
SHOULD ENCOUNTER STRONG LOW/MID LEVEL CONVERGENCE IN IOWA...AND
SHOULD THEN SEE AN UP-GROWTH IN CONVECTION ACROSS EASTERN IOWA
JUST AFTER THE 7PM TIME FRAME. LATEST GUIDANCE IS SHOWING THAT
THE CURRENT NORTHEASTWARD EXPANSION OF THIS INSTABILITY AXIS WILL
CONTINUE THIS EVENING AND ORIENT ITSELF ACROSS NORTH CENTRAL/EAST
CENTRAL ILLINOIS. THIS INCREASED INSTABILITY AS WELL AS
SUFFICIENT 0-3/0-6KM BULK SHEAR THIS EVENING LENDS ITSELF TO
SUPPORT A POSSIBLE WIND THREAT ACROSS NORTH CENTRAL...NORTHEAST
ILLINOIS...AS WELL AS NORTHWEST INDIANA AROUND THE 9PM TIME FRAME.
ANY DEVELOPMENT IS THEN EXPECTED TO SHIFT SOUTHEAST OF THE CWA
AFTER THE MIDNIGHT TIME FRAME...BUT THUNDERSTORMS STILL NOT BE
OUT OF THE QUESTION AFTER MIDNIGHT. PERSISTENT WAA AIDED BY A
STRONG LLJ COULD PROVIDE CONTINUED ISOLATED TO SCATTERED
DEVELOPMENT THROUGH EARLY WEDNESDAY MORNING.
SHIFTING GEARS TOWARDS WEDNESDAY...A SIGNIFICANT SEVERE WEATHER
OUTBREAK IS APPEARING TO BE POSSIBLE WITH VARYING MODES OF
CONVECTION. HAIL AND TORNADOES ARE POSSIBLE...AND A SIGNIFICANT
WIND THREAT ACROSS THE SOUTHERN HALF OF THE CWA COULD BE MORE
FAVORED THAN THE RUN OF THE MILL STRONG WINDS/GUSTS.
MULTIPLE ROUNDS OF THUNDERSTORMS WILL ONCE AGAIN BE POSSIBLE
ACROSS THE ENTIRE CWA TOMORROW BEGINNING TOMORROW MORNING.
ANTICIPATED UPSTREAM CONVECTION WILL LIKELY SHIFT EAST BY EARLY
WEDNESDAY MORNING BUT WITH LOCATION AND STRENGTH OF THESE STORMS
STILL NOT FULLY KNOWN. AT THIS TIME...IT APPEARS THAT THIS SHOULD
STAY TO THE NORTH OF THE CWA BUT WITH AREAS ACROSS FAR NORTHERN
ILLINOIS OBSERVING THE GREATER THREAT TO OBSERVE THIS
THUNDERSTORM POTENTIAL TOMORROW MORNING...BUT WITH ONCE AGAIN
CONFIDENCE REMAINING LOW. ITS CONCEIVABLE THAT WE COULD BE
DEALING WITH ANOTHER MCS COMPLEX AND ANOTHER ROUND OF HIGH
WINDS/HAIL. ANY REMAINING CONVECTION IS EXPECTED TO SHIFT EAST OF
THE AREA BY MID/LATE MORNING WITH A PERIOD OF DRY WEATHER
POSSIBLE FROM LATE MORNING THROUGH EARLY AFTERNOON.
CURRENT STRONGER AND MORE DEFINED MID LEVEL TROUGH SHIFTING
NORTHEAST ACROSS THE NORTHERN ROCKIES AT THIS TIME WILL MOVE EAST
THROUGH THE NORTHERN PLAINS TONIGHT INTO WEDNESDAY MORNING...AND
THEN DROP SOUTHEAST TOWARDS THE AREA BY MIDDAY. THIS WILL ALLOW
THE LOW OVER THE CENTRAL PLAINS TO SHIFT EAST REACHING THE
IOWA/MISSOURI LINE BY MID DAY...AND THEN CONTINUE EAST ACROSS
NORTH CENTRAL ILLINOIS IN THE AFTERNOON. THIS STRONG WAVE
BRINGING 50-60KT OF MID LEVEL FLOW WILL HELP THIS LOW STRENGTHEN
AS IT MOVES THROUGH THE REGION TOMORROW AFTERNOON. THIS STRONG
FORCING OWING TO THIS MID LEVEL FEATURE AND STRENGTHENING LOW IN
A MODERATELY TO STRONGLY UNSTABLE ENVIRONMENT WILL ALLOW FOR
RAPID GROWTH IN THUNDERSTORM COVERAGE AND INTENSITY STARTING AS
SOON AS THE 19Z TIME FRAME. MORE THAN EFFICIENT EFFECTIVE BULK
SHEAR AS WELL AS STEEP LAPSE RATES MOVING OVERHEAD WILL SUPPORT
EXPLOSIVE DEVELOPMENT. ALTHOUGH SEVERE WEATHER WILL BE POSSIBLE
ACROSS THE ENTIRE CWA TOMORROW AFTERNOON INTO THE EVENING...THE
MORE WIDESPREAD DEVELOPMENT IS EXPECTED FOR AREAS ALONG AND SOUTH
OF A DIXON TO CHICAGO LINE. ITS IN THIS AREA WHERE
MOISTURE/INSTABILITY WILL BE THE GREATEST...JUST ALONG AND SOUTH
OF THE SURFACE BOUNDARY. THE MID TO LATE AFTERNOON TIME FRAME IS
WHEN I EXPECT DEVELOPMENT TO REALLY GET GOING WITH SHEAR/WIND
PROFILES SUPPORTIVE OF DISCRETE CONVECTION WITH ROTATING UPDRAFTS
POSSIBLE. ITS DURING THIS INITIAL TIME FRAME THAT THE THREAT OF
TORNADOES WILL BE THE GREATEST NEAR THE SURFACE LOW OR ALONG THE
BOUNDARY. IT SHOULD NOT TAKE LONG AFTER INITIATION TOMORROW FOR
ANY DEVELOPMENT TO QUICKLY CONGEAL INTO A LINE WITH THEN STRONG
DAMAGING WINDS TO BE THE GREATER THREAT INTO THE AFTERNOON AND
EVENING. DO NOT WANT TO COMPLETELY RULE OUT THE TORNADO THREAT
THEREAFTER AS QLCS SPIN-UPS WILL DEFINITELY REMAIN A POSSIBILITY
AS THIS LINE OF THUNDERSTORMS SHIFTS SOUTHEAST ACROSS THE AREA.
EXPECT THIS COMPLEX OF THUNDERSTORMS TO CONTINUE EAST/SOUTHEAST
INTO THE EVENING WITH THE SEVERE THREAT DIMINISHING MORE TOWARDS
THE 9PM TIME FRAME. ALTHOUGH SHOWERS AND THUNDERSTORMS WILL BE
POSSIBLE AFTER MIDNIGHT...THE OVERALL SEVERE THREAT SHOULD BE LOW
AT THAT TIME. EXPECT MID LEVEL TROUGH AND ATTENDANT SURFACE LOW
TO CONTINUE EAST INTO THURSDAY MORNING WITH DRIER CONDITIONS
EXPECTED AS PRECIP SHIELD ALSO EXITS.
RODRIGUEZ
LONG TERM...FRIDAY THROUGH TUESDAY
THE EXTENDED WILL START OUT QUIET AND PLEASANT WITH HIGH PRESSURE
OVERHEAD AND ONSHORE BREEZES ON FRIDAY. HOWEVER...WE WILL QUICKLY
TRANSITION TO A MORE ACTIVE PATTERN AS STRONG UPPER RIDGING
CENTERED OVER THE PLAINS SHIFTS EASTWARD. THE CWA WILL RESIDE ON
THE NORTHERN FRINGE OF THE THE RIDGING...PUTTING US IN THE REGION
OF MODERATE WESTERLIES AND THUS DECENT DEEP LAYER SHEAR. THE
POTENTIAL EXISTS FOR RIDGE RUNNERS PRODUCING CLUSTERS OF
SHRA/TSRA STARTING AS EARLY AS LATE FRIDAY NIGHT INTO EARLY
SATURDAY. THE 12Z ECMWF AND 12Z GFS THEN DIVERGE IN THAT THE GFS
KEEPS US PRIMARILY IN A RING OF FIRE TYPE SET-UP UNTIL LATE
MONDAY...WHILE THE ECMWF HAS A MODESTLY DEEP UPPER TROUGH
BREAKING OFF FROM THE NORTHERN BRANCH WITH TROUGH AND ATTENDANT
SURFACE LOW TRACKING THROUGH WESTERN GREAT LAKES REGION SUNDAY
INTO MONDAY. CONSIDERING UNCERTAINTY...DID NOT MAKE MAJOR CHANGES
TO POPS FROM CONSENSUS BLEND...BUT EVEN DIVERGING MODEL SCENARIOS
KEEP PERIODIC CHANCES FOR SHOWERS AND THUNDERSTORMS UNTIL AT
LEAST A BRIEF QUIETER STRETCH ARRIVES BY NEXT TUESDAY AND
WEDNESDAY IN THE FORM OF HIGH PRESSURE.
ALSO DID NOT MAKE BIG CHANGES TO TEMPERATURES...BUT SYNOPTICALLY
SUNDAY AND MONDAY BOTH LOOK TO BE WARM AND FAIRLY HUMID AND SOME
GUIDANCE DOES HINT AT MID/UPPER 80S...WHICH MAKES SENSE WITH H85
TEMPS IN THE MID TEENS. THUS COULD SEE TEMPERATURES BOTH DAYS
BEING WARMER THAN CURRENTLY INDICATED. THE POTENTIAL FOR LAKE
BREEZES LENDS UNCERTAINTY TO LAKEFRONT TEMPERATURES SATURDAY
THROUGH MONDAY...WITH HIGHER CONFIDENCE IN SYNOPTIC ONSHORE FLOW
ON TUESDAY.
RC
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 03Z...
* MAGNITUDE OF THREAT SHRA/TSRA LATE TONIGHT THRU WED.
* SFC WND DIR DURG WED.
TRS
//DISCUSSION...UPDATED 00Z...
A SHORT WAVE TRAVELED FROM NW TO SE OVER THE AREA DURING THE
EARLY AND MID AFTERNOON. THIS PROVIDED ENOUGH MID LEVEL UVV TO
GENERATE SCT AND SHORT LINES OF QUICK MOVING TSRA WHICH HAD
EXITED THE CHI IN NW AND CENTRAL IND VS BY 21-22Z.
REST OF EVENING AND INTO THE OVERNIGHT EXPECTED WX TO BE
TRANQUIL. SUNSET AND RESULTING LOSS OF SFC HEATING HAS TURNED OFF
DIURNAL DESTABILIZATION OF BNDRY LAYER WHILE UPSTREAM SHORT
WAVES...ONE OVR SE SD AND NW IA AND THE SECOND OVER SW IA ND NW
MO ARE PROGGED TO PASSES TO THE N AND S OF THE LOCAL AREA
RESPECTIVELY OVERNIGHT. LOW AND MID LEVEL ISENTROPIC UPGLIDE IS
DEPICTED OVR THE AREA LATE OVERNIGHT ANS EARLY WED MORNING IT IS
WEAK AND DUE TO LACK OF MOISTURE SIG SAT PRES DEFICITS PERSIST.
BETTER FORCING IS PROGGED FROM NE AND E CENTRAL IA ACROSS FAR NW
IL AND SW TO E CENTRAL WI.
LATER WED AFTERNOON AS THE MAIN MID AND UPPER LEVEL TROFS
PROGRESS EWRD ACROSS THE MS RIVER...REACHING SRN WI AS WELL AS
NRN AND W CENTRAL IL BY 13.00Z. STRONGER FORCING...COOLING MID
LEVELS... DECREASING SAT PRES DEFICITS AND ENHANCED LOW LEVEL
CONVERGENCE AS AN ASSOCIATED SFC LOW MOVES E TO NRN IL WILL ALL
CONTRIBUTE TO INCREASE CHANCES OF SHRA/TSRA THE LATER INTO THE
AFTERNOON WE GO. AT THIS POINT LOOKS THAT THREAT WINDOW FOR
CONVECTION WILL BE 12.20Z-13.04Z...WITH HIGHEST CHANCES LATE
AFTERNOON THRU MID EVENING AS THE ABOVE MENTIONED SHORT WAVE
TROFS CONT TO APPROACH AND MOV OVR THE AREA.
WEAK SFC PRES GRADIENT WILL RESULT IN LIGHT OR NIL WIND TONIGHT.
WITH MINIMAL TO NO MIXING IN A SHALLOW AT MOST BNDRY LYR SOME
MVFR VSBYS IN BR EXPECTED LATER TONIGHT INTO EARLY WED MORNING...
WHEN SUNUP WILL START THE MIXING PROCESS.
AS FAR AS WIND DIRECTION ON WED...MODELS OFFERING VARIOUS
SOLUTIONS DEPENDING ON WHERE THE SURFACE LOW AND THE SURFACE
BOUNDARY IT WILL WILL RIPPLING EWRD ALONG WILL BE LOCATED.
GENERAL CONSENSUS IT THAT IT WILL RUN W-E FROM/NEAR THE QUAD
CITIES TO THE S TIP OF LK MI. THIS WOULD KEEP ORD AND MDW WITH
THE PREVAILING SFC WNDS FROM THE ENE-ESE DURG THE DAY TIL THE SFC
LOW REACHES THE IND BORDER THE FIRST PART OF WED EVE WITH WNDS
RESPONDING BY BACKING TO NE-N.
TRS
//ORD AND MDW CONFIDENCE...UPDATED 03Z...
* MODERATE CONFIDENCE IN TIMING OF BEST THREAT OF CONVECTIVE
ACTIVITY.
* MODERATE CONFIDENCE IN WND DIR DURG DAYTIME WED.
TRS
//OUTLOOK FOR ORD/MDW FOR 12Z THU-12Z TUE...UPDATED 00Z...
THU AND FRI...VFR. WX NIL.
SAT THRU MON...VFR. CHC TSRA WITH LOCAL MVFR/IFR.
TRS
&&
.MARINE...
243 PM...MAIN FORECAST CONCERN/CHALLENGE THROUGH WEDNESDAY MORNING
REMAINS DENSE FOG. SOUTHERLY WINDS HAVE PUSHED THE FOG NORTH...
ROUGHLY FROM HOLLAND TO MILWAUKEE. LITTLE IMPROVEMENT SEEN NORTH
OF THERE. SOUTHERLY WINDS DIMINISH THIS EVENING AND BEGIN TURNING
BACK EAST AND THEN NORTHEAST OVERNIGHT INTO WEDNESDAY MORNING...
SO THERE IS SOME POTENTIAL FOR THE FOG TO DRIFT BACK SOUTH. WHILE
CONFIDENCE REMAINS SOMEWHAT LOW...HAVE OPTED TO CONTINUE THE DENSE
FOG ADVISORY FOR ALL OF THE OPEN WATERS THROUGH WEDNESDAY MORNING.
LOW PRESSURE OVER COLORADO WILL MOVE EAST AND DEEPEN TONIGHT...
PASSING ACROSS NORTH CENTRAL ILLINOIS WEDNESDAY AFTERNOON AND THEN
ACROSS NORTHERN INDIANA WEDNESDAY EVENING. THE GRADIENT WILL
TIGHTEN AHEAD OF THIS LOW WITH NORTHEASTERLY WINDS INCREASING
WEDNESDAY AFTERNOON...THEN TURNING NORTHERLY AND INCREASING FURTHER
WEDNESDAY EVENING. A PERIOD OF 15-25 KTS STILL LOOKS ON TRACK AND
OVER THE SOUTHERN THIRD OR QUARTER OF THE LAKE...THERE COULD BE A
PERIOD OF 20-25 KTS WITH GUSTS PERHAPS AS HIGH AS 30 KTS. THE
GRADIENT WILL BE SLOW TO RELAX THURSDAY INTO THURSDAY NIGHT AS HIGH
PRESSURE BUILDS ACROSS THE UPPER MIDWEST AND NORTHERN LAKES...
EVENTUALLY SPREADING ACROSS THE LAKES REGION FRIDAY. CMS
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...DENSE FOG ADVISORY...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-
LMZ565-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-
LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 9 AM
WEDNESDAY.
&&
$$
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WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
837 PM CDT TUE JUN 11 2013
.DISCUSSION...
834 PM CDT
A FEW THOUGHTS REGARDING THE THUNDERSTORM THREAT OVERNIGHT AND THE
MODERATE RISK FOR SEVERE WEATHER WEDNESDAY...
THIS EVENING...A WARM FRONT EXTENDS FROM WESTERN IOWA EAST TOWARDS
IOWA CITY...THEN LOSES ITS DEFINITION SOUTHEAST INTO CENTRAL
ILLINOIS. LOW TO MID 70 DEWPOINTS ARE POOLING ALONG THE BOUNDARY TO
OUR WEST...BUT AS A 20Z SOUNDING OUT OF DVN SHOWED...A STRONG CAP IS
IN PLACE WITH 825MB TEMPS AROUND 21C. LATEST RAP GUIDANCE INDICATES
THE THE CAP WILL REMAIN IN PLACE THROUGH THE REMAINDER OF THE
EVENING AND TONIGHT. WITH THAT SAID....THE THREAT FOR SEVERE WEATHER
THROUGH THE REMAINDER OF TODAY HAS GREATLY DIMINISHED. FOCUS TURNS
OUT TO THE WEST TONIGHT WHERE A 50-60KT LOW LEVEL JET IS EXPECTED TO
DEVELOP WITH THE BEST MOISTURE CONVERGENCE FOCUSED OVER CENTRAL
NEBRASKA...AND BY MIDNIGHT TONIGHT SLIGHTLY FARTHER EAST OVER THE
MID MISSOURI VALLEY. DESPITE THE FOCUS BEING WELL OFF TO OUR
WEST...THERE IS SOME ASCENT ALONG THE WARM FRONT SO CANT RULE OUT
SOMETHING TRYING TO DEVELOP THIS EVENING NORTH OF THE WARM
FRONT AND MOVING INTO NORTHERN ILLINOIS...BUT EXPECT COVERAGE TO
BE LOW AWAY FROM THE BETTER FORCING WITH THE LLJ. WITH THAT IN
MIND...LOWERED POPS ACROSS MUCH OF THE CWA FOR THE OVERNIGHT
HOURS AND FEEL THEY MAY STILL BE ON THE HIGH END. CONVECTIVE
ALLOWING MODELS STILL SHOW AN MCS DEVELOPING AT THE NOSE OF THE
LLJ TONIGHT...AND BY DAYBREAK TOMORROW POSSIBLY MOVING INTO
NORTHWESTERN ILLINOIS...BUT MORE LIKELY STAYING NORTH OF THE STATE
LINE. EITHER WAY...LLJ IS VEERING AND WEAKENING BY THAT TIME SO
CONVECTION SHOULD BE IN A WEAKENING PHASE.
THE STORM PREDICTION CENTER CONTINUES TO CARRY US UNDER A MODERATE
RISK WEDNESDAY AND THIS SEEMS TO BE ON TRACK. APPEARS WE WILL BE
UNDER A PRETTY DYNAMIC ENVIRONMENT TOMORROW AS A COUPLED JET SETS UP
WITH THE BEST UPPER LEVEL DIVERGENCE OVER CENTRAL AND NORTHERN
ILLINOIS. MODERATE HEIGHT FALLS ASSOCIATED WITH THE MID LEVEL WAVE
MOVING INTO THE AREA LATE AFTERNOON/EARLY EVENING TOMORROW WILL
PROVIDE LARGE SCALE ASCENT ACROSS THE AREA TO HELP WEAKEN THE CAP.
THE SURFACE LOW TRACKS EAST ACROSS THE MISSISSIPPI VALLEY JUST SOUTH
OF MLI...THOUGH THERE ARE SOME MODELS SUGGESTING THE LOW TRACK AND
RESULTING SEVERE THREAT MAY TRACK SLIGHTLY FARTHER NORTH. SOME
MODELS ALSO INDICATE THE LOW DEEPENING SLIGHTLY TOMORROW AFTERNOON
WITH 2-4MB PRESSURE FALLS OVERSPREADING AREAS SOUTH OF I-80. THIS
WILL ONLY HELP TO ENHANCE WHAT ALREADY LOOKS TO BE PRETTY
STRONG LOW LEVEL HELICITY TOMORROW. DEEP LAYER SHEAR TOMORROW IS
ALSO FORECAST TO BE QUITE STRONG. ALL SAID THERE IS CONCERN FOR
DISCRETE SUPERCELLS DEVELOPING IN THE AFTERNOON WITH THE WHOLE GAMUT
OF SEVERE WEATHER POSSIBLE...LARGE HAIL...DAMAGING WINDS AND QUITE
POSSIBLY TORNADOES. STORMS SHOULD EVENTUALLY CONGEAL INTO A LINE
WITH THE MAIN THREAT TURNING BECOMING DAMAGING WINDS...THOUGH QLCS
TORNADOES WILL STILL BE A CONCERN. HOW QUICKLY WE TRANSITION FROM
DISCRETE SUPERCELLS TO A LINEAR MCS IS UNCERTAIN. INTERESTING TO
NOTE THAT ONE OF THE TOP CIPS ANALOGS IS JUNE 05 2010 WHICH DID HAVE
DISCRETE SUPERCELLS WITH TORNADOES LATER INTO THE EVENING.
DEUBELBEISS
&&
.PREV DISCUSSION...
300 PM CDT
MAIN FORECAST CONCERNS/CHALLENGES IN THE NEAR TERM ARE WITH
MULTIPLE ROUNDS OF CONVECTION POSSIBLE ACROSS THE ENTIRE CWA
TONIGHT THROUGH WEDNESDAY NIGHT WITH SEVERE WEATHER NOT OUT OF THE
QUESTION THIS EVENING AND OVERNIGHT...BUT WITH A MORE SIGNIFICANT
SEVERE WEATHER OUTBREAK BECOMING INCREASINGLY MORE POSSIBLE ACROSS
A PORTION OF THE CWA ON WEDNESDAY.
IN THE NEAR TERM...CONTINUE TO MONITOR CONVECTION DEVELOPING JUST
SOUTHWEST/SOUTH OF THE CWA AT THIS TIME AS A MID LEVEL IMPULSE
SLIDES EAST ACROSS THE AREA AND ENCOUNTERS SOME WEAK LOW/MID LEVEL
CONVERGENCE IN AND AROUND SHIFTING SURFACE TROUGH ACROSS IOWA.
THIS AREA OF CONVECTION SHOULD CONTINUE EAST/SOUTHEAST WITH TIME
FOR THE REMAINDER OF THE AFTERNOON MAINLY ONLY AFFECTING AREAS
FROM LA SALLE IN ILLINOIS SOUTHEAST TO RENSSELAER IN
INDIANA...SUPPORTED BY THIS WAVE AND CURRENT WAA IN PLACE.
ALTHOUGH INSTABILITY REMAINS RATHER WEAK ACROSS THESE AREAS AS
WELL AS CIN IN PLACE...LATEST TRENDS SUPPORT A NORTHEASTWARD
EXPANSION OF THE INSTABILITY AXIS AS WELL AS WEAKENING CIN.
DESPITE WEAKLY FORCED...THESE CONDITIONS COINCIDING WITH
SUFFICIENT BULK SHEAR COULD SUPPORT AN ISOLATED HAIL/WIND THREAT
THROUGH LATE AFTERNOON. GOING INTO THE EARLY EVENING...COULD SEE A
DRY PERIOD FOR MOST OF NORTHERN ILLINOIS AND NORTHWEST INDIANA BUT
WITH THE POSSIBILITY FOR AN INCREASE IN COVERAGE OF THUNDERSTORMS
ONCE AGAIN LATER IN THE EVENING. THIS IS A DEFINITE POSSIBILITY
ESPECIALLY AS SEVERAL MID LEVEL FEATURES/SPEED MAXES ARE
ANTICIPATED TO ROUND THE MID LEVEL RIDGE...AS WELL AS A VEERING
LLJ STRENGTHENS THIS EVENING.
CONTINUE TO MONITOR THESE MID LEVEL FEATURES TRACKING EAST ACROSS
THE CENTRAL AND NORTHERN PLAINS ON LATEST VISIBLE
SATELLITE...TRYING TO GRAB A HANDLE ON THIS POSSIBILITY OF
INCREASED CHANCES FOR CONVECTION LATER THIS EVENING. THIS IS DUE
TO MOST GUIDANCE VARYING TO SOME DEGREE ON PLACEMENT AS WELL AS
TIMING THIS EVENING...WITH CONFIDENCE NOT THE GREATEST FOR
CONVECTIVE EVOLUTION THIS EVENING. ALTHOUGH LATEST THOUGHTS FOR
THIS EVENING ONCE AGAIN DO INCLUDE THE POSSIBILITY FOR AN
INCREASED CHANCE FOR THUNDERSTORMS AS WELL AS THE POSSIBILITY FOR
SEVERE WEATHER...DAMAGING WINDS AND HAIL ONCE AGAIN THE MAIN
THREATS. MID LEVEL FEATURE MOVING OUT OF THE CENTRAL PLAINS SHOULD
ENCOUNTER STRONG LOW/MID LEVEL CONVERGENCE IN IOWA...AND SHOULD
THEN SEE AN UPGROWTH IN CONVECTION ACROSS EASTERN IOWA JUST AFTER
THE 7PM TIME FRAME. LATEST GUIDANCE IS SHOWING THAT THE CURRENT
NORTHEASTWARD EXPANSION OF THIS INSTABILITY AXIS WILL CONTINUE
THIS EVENING AND ORIENT ITSELF ACROSS NORTH CENTRAL/EAST CENTRAL
ILLINOIS. THIS INCREASED INSTABILITY AS WELL AS SUFFICIENT
0-3/0-6KM BULK SHEAR THIS EVENING LENDS ITSELF TO SUPPORT A
POSSIBLE WIND THREAT ACROSS NORTH CENTRAL...NORTHEAST
ILLINOIS...AS WELL AS NORTHWEST INDIANA AROUND THE 9PM TIME FRAME.
ANY DEVELOPMENT IS THEN EXPECTED TO SHIFT SOUTHEAST OF THE CWA
AFTER THE MIDNIGHT TIME FRAME...BUT THUNDERSTORMS STILL NOT BE OUT
OF THE QUESTION AFTER MIDNIGHT. PERSISTENT WAA AIDED BY A STRONG
LLJ COULD PROVIDE CONTINUED ISOLATED TO SCATTERED DEVELOPMENT
THROUGH EARLY WEDNESDAY MORNING.
SHIFTING GEARS TOWARDS WEDNESDAY...A SIGNIFICANT SEVERE WEATHER
OUTBREAK IS APPEARING TO BE POSSIBLE WITH VARYING MODES OF
CONVECTION. HAIL AND TORNADOES ARE POSSIBLE...AND A SIGNIFICANT
WIND THREAT ACROSS THE SOUTHERN HALF OF THE CWA COULD BE MORE
FAVORED THAN THE RUN OF THE MILL STRONG WINDS/GUSTS.
MULTIPLE ROUNDS OF THUNDERSTORMS WILL ONCE AGAIN BE POSSIBLE
ACROSS THE ENTIRE CWA TOMORROW BEGINNING TOMORROW MORNING.
ANTICIPATED UPSTREAM CONVECTION WILL LIKELY SHIFT EAST BY EARLY
WEDNESDAY MORNING BUT WITH LOCATION AND STRENGTH OF THESE STORMS
STILL NOT FULLY KNOWN. AT THIS TIME...IT APPEARS THAT THIS SHOULD
STAY TO THE NORTH OF THE CWA BUT WITH AREAS ACROSS FAR NORTHERN
ILLINOIS OBSERVING THE GREATER THREAT TO OBSERVE THIS THUNDERSTORM
POTENTIAL TOMORROW MORNING...BUT WITH ONCE AGAIN CONFIDENCE
REMAINING LOW. ITS CONCEIVABLE THAT WE COULD BE DEALING WITH
ANOTHER MCS COMPLEX AND ANOTHER ROUND OF HIGH WINDS/HAIL. ANY
REMAINING CONVECTION IS EXPECTED TO SHIFT EAST OF THE AREA BY
MID/LATE MORNING WITH A PERIOD OF DRY WEATHER POSSIBLE FROM LATE
MORNING THROUGH EARLY AFTERNOON.
CURRENT STRONGER AND MORE DEFINED MID LEVEL TROUGH SHIFTING
NORTHEAST ACROSS THE NORTHERN ROCKIES AT THIS TIME WILL MOVE EAST
THROUGH THE NORTHERN PLAINS TONIGHT INTO WEDNESDAY MORNING...AND
THEN DROP SOUTHEAST TOWARDS THE AREA BY MIDDAY. THIS WILL ALLOW
THE LOW OVER THE CENTRAL PLAINS TO SHIFT EAST REACHING THE
IOWA/MISSOURI LINE BY MID DAY...AND THEN CONTINUE EAST ACROSS
NORTH CENTRAL ILLINOIS IN THE AFTERNOON. THIS STRONG WAVE BRINGING
50-60KT OF MID LEVEL FLOW WILL HELP THIS LOW STRENGTHEN AS IT
MOVES THROUGH THE REGION TOMORROW AFTERNOON. THIS STRONG FORCING
OWING TO THIS MID LEVEL FEATURE AND STRENGTHENING LOW IN A
MODERATELY TO STRONGLY UNSTABLE ENVIRONMENT WILL ALLOW FOR RAPID
GROWTH IN THUNDERSTORM COVERAGE AND INTENSITY STARTING AS SOON AS
THE 19Z TIME FRAME. MORE THAN EFFICIENT EFFECTIVE BULK SHEAR AS
WELL AS STEEP LAPSE RATES MOVING OVERHEAD WILL SUPPORT EXPLOSIVE
DEVELOPMENT. ALTHOUGH SEVERE WEATHER WILL BE POSSIBLE ACROSS THE
ENTIRE CWA TOMORROW AFTERNOON INTO THE EVENING...THE MORE
WIDESPREAD DEVELOPMENT IS EXPECTED FOR AREAS ALONG AND SOUTH OF A
DIXON TO CHICAGO LINE. ITS IN THIS AREA WHERE MOISTURE/INSTABILITY
WILL BE THE GREATEST...JUST ALONG AND SOUTH OF THE SURFACE
BOUNDARY. THE MID TO LATE AFTERNOON TIME FRAME IS WHEN I EXPECT
DEVELOPMENT TO REALLY GET GOING WITH SHEAR/WIND PROFILES
SUPPORTIVE OF DISCRETE CONVECTION WITH ROTATING UPDRAFTS POSSIBLE.
ITS DURING THIS INITIAL TIME FRAME THAT THE THREAT OF TORNADOES
WILL BE THE GREATEST NEAR THE SURFACE LOW OR ALONG THE BOUNDARY.
IT SHOULD NOT TAKE LONG AFTER INITIATION TOMORROW FOR ANY
DEVELOPMENT TO QUICKLY CONGEAL INTO A LINE WITH THEN STRONG
DAMAGING WINDS TO BE THE GREATER THREAT INTO THE AFTERNOON AND
EVENING. DONT WANT TO COMPLETELY RULE OUT THE TORNADO THREAT
THEREAFTER AS QLCS SPINUPS WILL DEFINITELY REMAIN A POSSIBILITY AS
THIS LINE OF THUNDERSTORMS SHIFTS SOUTHEAST ACROSS THE AREA.
EXPECT THIS COMPLEX OF THUNDERSTORMS TO CONTINUE EAST/SOUTHEAST
INTO THE EVENING WITH THE SEVERE THREAT DIMINISHING MORE TOWARDS
THE 9PM TIME FRAME. ALTHOUGH SHOWERS AND THUNDERSTORMS WILL BE
POSSIBLE AFTER MIDNIGHT...THE OVERALL SEVERE THREAT SHOULD BE LOW
AT THAT TIME. EXPECT MID LEVEL TROUGH AND ATTENDANT SURFACE LOW TO
CONTINUE EAST INTO THURSDAY MORNING WITH DRIER CONDITIONS EXPECTED
AS PRECIP SHIELD ALSO EXITS.
RODRIGUEZ
LONG TERM...FRIDAY THROUGH TUESDAY
THE EXTENDED WILL START OUT QUIET AND PLEASANT WITH HIGH PRESSURE
OVERHEAD AND ONSHORE BREEZES ON FRIDAY. HOWEVER...WE WILL QUICKLY
TRANSITION TO A MORE ACTIVE PATTERN AS STRONG UPPER RIDGING CENTERED
OVER THE PLAINS SHIFTS EASTWARD. THE CWA WILL RESIDE ON THE
NORTHERN FRINGE OF THE THE RIDGING...PUTTING US IN THE REGION OF
MODERATE WESTERLIES AND THUS DECENT DEEP LAYER SHEAR. THE POTENTIAL
EXISTS FOR RIDGE RUNNERS PRODUCING CLUSTERS OF SHRA/TSRA STARTING AS
EARLY AS LATE FRIDAY NIGHT INTO EARLY SATURDAY. THE 12Z ECMWF AND
12Z GFS THEN DIVERGE IN THAT THE GFS KEEPS US PRIMARILY IN A RING OF
FIRE TYPE SET-UP UNTIL LATE MONDAY...WHILE THE ECMWF HAS A MODESTLY
DEEP UPPER TROUGH BREAKING OFF FROM THE NORTHERN BRANCH WITH TROUGH
AND ATTENDANT SURFACE LOW TRACKING THROUGH WESTERN GREAT LAKES
REGION SUNDAY INTO MONDAY. CONSIDERING UNCERTAINTY...DID NOT MAKE
MAJOR CHANGES TO POPS FROM CONSENSUS BLEND...BUT EVEN DIVERGING
MODEL SCENARIOS KEEP PERIODIC CHANCES FOR SHOWERS AND THUNDERSTORMS
UNTIL AT LEAST A BRIEF QUIETER STRETCH ARRIVES BY NEXT TUESDAY AND
WEDNESDAY IN THE FORM OF HIGH PRESSURE.
ALSO DID NOT MAKE BIG CHANGES TO TEMPERATURES...BUT SYNOPTICALLY
SUNDAY AND MONDAY BOTH LOOK TO BE WARM AND FAIRLY HUMID AND SOME
GUIDANCE DOES HINT AT MID/UPPER 80S...WHICH MAKES SENSE WITH H85
TEMPS IN THE MID TEENS. THUS COULD SEE TEMPERATURES BOTH DAYS BEING
WARMER THAN CURRENTLY INDICATED. THE POTENTIAL FOR LAKE BREEZES
LENDS UNCERTAINTY TO LAKEFRONT TEMPERATURES SATURDAY THROUGH
MONDAY...WITH HIGHER CONFIDENCE IN SYNOPTIC ONSHORE FLOW ON TUESDAY.
RC
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 00Z...
* MAGNITUDE OF THREAT SHRA/TSRA LATE TONIGHT THRU WED.
* SFC WND DIR DURG WED.
TRS
//DISCUSSION...UPDATED 00Z...
A SHORT WAVE TRAVELED FROM NW TO SE OVER THE AREA DURING THE
EARLY AND MID AFTERNOON. THIS PROVIDED ENOUGH MID LEVEL UVV TO
GENERATE SCT AND SHORT LINES OF QUICK MOVING TSRA WHICH HAD EXITED
THE CHI IN NW AND CENTRAL IND VS BY 21-22Z.
REST OF EVENING AND INTO THE OVERNIGHT EXPECTED WX TO BE TRANQUIL.
SUNSET AND RESULTING LOSS OF SFC HEATING HAS TURNED OFF DIURNAL
DESTABILIZATION OF BNDRY LAYER WHILE UPSTREAM SHOT WAVES...ONE OVR
SE SD AND NW IA AND THE SECOND OVER SW IA ND NW MO ARE PROGGED TO
PASSES TO THE N AND S OF THE LOCAL AREA RESPECTIVELY OVERNIGHT.
LOW AND MID LEVEL ISENTROPIC UPGLIDE IS DEPICTED OVR THE AREA
LATE OVERNIGHT ANS EARLY WED MORNING IT IS WEAK AND DUE TO LACK OF
MOISTURE SIG SAT PRES DEFICITS PERSIST. BETTER FORCING IS PROGGED
FROM NE AND E CENTRAL IA ACROSS FAR NW IL AND SW TO E CENTRAL WI.
LATER WED AFTERNOON AS THE MAIN MID AND UPPER LEVEL TROFS PROGRESS
EWRD ACROSS THE MS RIVER...REACHING SRN WI AS WELL AS NRN AND W
CENTRAL IL BY 13.00Z. STRONGER FORCING...COOLING MID LEVELS...
DECREASING SAT PRES DEFICITS AND ENHANCED LOW LEVEL CONVERGENCE
AS AN ASSOCIATED SFC LOW MOVES E TO NRN IL WILL ALL CONTRIBUTE TO
INCREASE CHANCES OF SHRA/TSRA THE LATER INTO THE AFTERNOON WE GO.
AT THIS POINT LOOKS THAT THREAT WINDOW FOR CONVECTION WILL BE
12.20Z-13.04Z...WITH HIGHEST CHANCES LATE AFTERNOON THRU MID
EVENING AS THE ABOVE MENTIONED SHORT WAVE TROFS CONT TO APPROACH
AND MOV OVR THE AREA.
WEAK SFC PRES GRADIENT WILL RESULT IN LIGHT OR NIL WIND TONIGHT.
WITH MINIMAL TO NO MIXING IN A SHALLOW AT MOST BNDRY LYR SOME MVFR
VSBYS IN BR EXPECTED LATER TONIGHT INTO EARLY WED MORNING...WHEN
SUNUP WILL START THE MIXING PROCESS.
AS FAR AS WIND DIRECTION ON WED...MODELS OFFERING VARIOUS
SOLUTIONS DEPENDING ON WHERE THE SURFACE LOW AND THE SURFACE
BOUNDARY IT WILL WILL RIPPLING EWRD ALONG WILL BE LOCATED. GENERAL
CONSENSUS IT THAT IT WILL RUN W-E FROM/NEAR THE QUAD CITIES TO THE
S TIP OF LK MI. THIS WOULD KEEP ORD AND MDW WITH THE PREVAILING
SFC WNDS FROM THE ENE-ESE DURG THE DAY TIL THE SFC LOW REACHES THE
IND BORDER THE FIRST PART OF WED EVE WITH WNDS RESPONDING BY
BACKING TO NE-N.
TRS
//ORD AND MDW CONFIDENCE...UPDATED 00Z...
* MODERATE CONFIDENCE IN TIMING OF BEST THREAT OF CONVECTIVE
ACTIVITY.
* MODERATE CONFIDENCE IN WND DIR DURG DAYTIME WED.
TRS
//OUTLOOK FOR ORD/MDW FOR 12Z THU-12Z TUE...UPDATED 00Z...
THU AND FRI...VFR. WX NIL.
SAT THRU MON...VFR. CHC TSRA WITH LOCAL MVFR/IFR.
TRS
&&
.MARINE...
243 PM...MAIN FORECAST CONCERN/CHALLENGE THROUGH WEDNESDAY MORNING
REMAINS DENSE FOG. SOUTHERLY WINDS HAVE PUSHED THE FOG NORTH...
ROUGHLY FROM HOLLAND TO MILWAUKEE. LITTLE IMPROVEMENT SEEN NORTH
OF THERE. SOUTHERLY WINDS DIMINISH THIS EVENING AND BEGIN TURNING
BACK EAST AND THEN NORTHEAST OVERNIGHT INTO WEDNESDAY MORNING...
SO THERE IS SOME POTENTIAL FOR THE FOG TO DRIFT BACK SOUTH. WHILE
CONFIDENCE REMAINS SOMEWHAT LOW...HAVE OPTED TO CONTINUE THE DENSE
FOG ADVISORY FOR ALL OF THE OPEN WATERS THROUGH WEDNESDAY MORNING.
LOW PRESSURE OVER COLORADO WILL MOVE EAST AND DEEPEN TONIGHT...
PASSING ACROSS NORTH CENTRAL ILLINOIS WEDNESDAY AFTERNOON AND THEN
ACROSS NORTHERN INDIANA WEDNESDAY EVENING. THE GRADIENT WILL
TIGHTEN AHEAD OF THIS LOW WITH NORTHEASTERLY WINDS INCREASING
WEDNESDAY AFTERNOON...THEN TURNING NORTHERLY AND INCREASING FURTHER
WEDNESDAY EVENING. A PERIOD OF 15-25 KTS STILL LOOKS ON TRACK AND
OVER THE SOUTHERN THIRD OR QUARTER OF THE LAKE...THERE COULD BE A
PERIOD OF 20-25 KTS WITH GUSTS PERHAPS AS HIGH AS 30 KTS. THE
GRADIENT WILL BE SLOW TO RELAX THURSDAY INTO THURSDAY NIGHT AS HIGH
PRESSURE BUILDS ACROSS THE UPPER MIDWEST AND NORTHERN LAKES...
EVENTUALLY SPREADING ACROSS THE LAKES REGION FRIDAY. CMS
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...DENSE FOG ADVISORY...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-
LMZ565-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-
LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 9 AM
WEDNESDAY.
&&
$$
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TO ACCOUNT FOR LATEST TRENDS. PREVIOUS FORECAST DISCUSSION
FOLLOWS...
PRECIPITATION LOOKS LIKE A GOOD BET ACROSS CENTRAL INDIANA
TONIGHT. THE FIRST SHOT LOOKS TO ARRIVE FROM THE SOUTH AS THE
PRECIP OVER KENTUCKY ADVECTS INTO CENTRAL INDIANA. THE GFS 305K
ISENTROPIC SURFACE SHOWS GOOD LIFT ASSOCIATED WITH THIS FEATURE
ADVECTING NORTHEAST ACROSS THE EASTERN PARTS OF OUR FORECAST AREA
LATE THIS AFTERNOON AND EARLY THIS EVENING. THE SECOND SHOT AT
PRECIPITATION COMES AFTER 00Z AS THE PRECIP ASSOCIATED WITH THE
TROUGH OF LOW PRESSURE ARRIVES. GOOD LOWER LEVEL Q VECTOR
CONVERGENCE PUSHES THROUGH THE AREA WITH THE TROUGH OF LOW
PRESSURE AS THE HRRR SUGGESTS AN AREA OF SHRA WITH TSRA PUSHING
THROUGH THE STATE THIS EVENING. FURTHERMORE...FORECAST SOUNDINGS
INDICATE GOOD SATURATION...PARTICULARLY DURING BY 06Z TIME FRAME.
THUS WILL TREND POPS HIGHER THAN MAVMOS...PARTICULARLY EARLY ON IN
THE EAST AS THE TSRA AND SHRA ARE EXPECTED TO MOVE IN AND ACROSS
THE AREA AND THEN AGAIN ACROSS THE WEST AND CENTRAL AREA DURING
THE MIDDLE TO LATER PARTS OF THE FORECAST PERIOD. GIVEN THE CLOUDS
AND RAIN WILL TREND LOWS AT OR ABOVE MAVMOS.
&&
.SHORT TERM /MONDAY THROUGH WEDNESDAY/...
ISSUED AT 103 PM EDT SUN JUN 9 2013
MAIN FORECAST CHALLENGE FOR THIS PERIOD WILL BE POPS N MONDAY. GFS
AND NAM DEPICT THE LOW PRESSURE SYSTEM OVER IOWA PUSHING THROUGH
AND EXITING CENTRAL INDIANA ON MONDAY AFTERNOON. BROAD CYCLONIC
LOWER LEVEL FLOW WILL BE IN PLACE. FORECAST SOUNDINGS SHOWS STEEP
LAPSE RATES BY 18Z MONDAY WITH GOOD MOISTURE STILL AVAILABLE. CAPE
REMAINS IN EXCESS OF 1000 J/KG AND CONVECTIVE TEMPS ARE ONLY IN
THE LOWER 70S. THUS GIVEN THE FLOW...THE FORCING AND DAYTIME
HEATING SOME SCT SHRA AND ISOLATED TSRA WILL BE POSSIBLE. WILL
STICK CLOSE TO THE TO THE MAVMOS POPS HERE GIVEN THE HIT OR MISS
CHANCES OF CONVECTIVE PRECIP IN THIS SET UP. WITH LITTLE CHANGE IN
THE AIR MASS WILL USE A BLEND ON HIGHS AS GOOD CLOUD COVER COULD
BE PRESENT WITH THE PASSING LOW.
THE LOW PRESSURE SYSTEM DEPARTS ON MONDAY AND AS GOOD RIDGING
BUILDS ALOFT ON MONDAY NIGHT THROUGH TUESDAY. TIME HEIGHTS AND
FORECAST SOUNDINGS DRY OUT THE COLUMN CONSIDERABLE AS THE
CONVECTIVE TEMPS BECOME UNREACHABLE. AGAIN THERE IS VERY LITTLE
CHANGE IN THE AIR MASS FOR THIS SYSTEM AND AS THE RIDGE QUICKLY
MOVES EAST OF INDIANA BY LATE TUESDAY...STRONG WARM AIR ADVECTION
ONCE AGAIN TAKES SHAPE ACROSS CENTRAL INDIANA. THE GFS FORECAST
SOUNDINGS HINT EVEN WITH THE WARM AND HUMID AIR MASS IN PLACE
700MB TEMPS WILL BE NEAR 12C...WHICH IS USUALLY A PRETTY DARN GOOD
CAP. THUS WILL KEEP A DRY FORECAST FROM MONDAY NIGHT THROUGH
WEDNESDAY...WITH SLOWLY MODERATING TEMPERATURES WARMER EACH DAY.
WILL TREND TOWARD THE WARMER SIDE OF GUIDANCE DURING THE MONDAY
NIGHT THROUGH WEDNESDAY TIME PERIOD.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
ISSUED AT 250 PM EDT SUN JUN 9 2013
MAIN FOCUS OF THE EXTENDED WILL BE STORM CHANCES WEDNESDAY NIGHT...
EARLY THURSDAY AND AGAIN OVER THE WEEKEND. MODELS REMAIN IN GOOD
AGREEMENT IN MAINTAINING A NORTHWEST FLOW ALOFT ACROSS THE
NORTHERN U.S. FROM THE PLAINS EASTWARD. A STRONG UPPER RIDGE
WILL BE OVER TEXAS AND OKLAHOMA WHILE AN UPPER UPPER TROUGH MOVES
FROM THE GREAT LAKES INTO NEW ENGLAND AROUND THURSDAY FOLLOWED BY
A WEAKER SYSTEM LATE SATURDAY NIGHT AND SUNDAY.
MODELS HAVE TRENDED A LITTLE WETTER AND FARTHER SOUTH WITH A
POSSIBLE MCS MOVING ACROSS OUR REGION WEDNESDAY NIGHT. SCATTERED
THUNDERSTORMS MAY LINGER INTO THURSDAY. HOWEVER WITH THE MODELS
BEING VERY QUICK TO DRY US OUT...WILL DROP MENTION OF THUNDERSTORMS
FOR THURSDAY AFTERNOON.
THURSDAY NIGHT THROUGH EARLY SATURDAY WILL BE DRY AS A WEAK RIDGE
OF HIGH PRESSURE MOVES EAST ACROSS OUR REGION. MODELS ARE A LITTLE
MORE PROGRESSIVE WITH THE WEEKEND. BUT THEY MAY BE A BIT TOO FAST.
FOR NOW LEAN TOWARDS THE SLOWER HPC SOLUTION.
WENT WITH A MOS BLEND MOST PERIODS...EXCEPT A TAD WARMER FOR HIGHS
FRIDAY AND SATURDAY AS THERE WILL BE LOTS OF SUN AND INCREASING
WARM ADVECTION.
&&
.AVIATION /DISCUSSION FOR 100600Z TAF ISSUANCE/...
ISSUED AT 1256 AM EDT MON JUN 10 2013
SCATTERED SHOWERS WITH POTENTIAL FOR MVFR WILL GIVE WAY TO MVFR
CONDITIONS LATER DURING THE NIGHT. THESE SHOULD PERSIST UNTIL MONDAY
AFTERNOON...WHEN VFR RETURNS..
BULK OF CONVECTION SHOULD BE OUT OF THE TAF SITES BY VALID TIME
LEAVING BEHIND SCATTERED SHOWERS. THESE SHOULD CONTINUE THROUGH THE
MORNING HOURS ON MONDAY AS AN UPPER LOW MOVES INTO THE AREA.
OUTSIDE OF SHOWERS PREDOMINANT MVFR CEILINGS AND PERHAPS
VISIBILITIES WILL MOVE IN OVERNIGHT AND PERSIST THROUGH MONDAY
MORNING AS THE UPPER LOW MOVES IN. CEILINGS SHOULD LIFT TO VFR BY
17Z OR SO. ADDITIONAL SCATTERED SHOWERS MAY DEVELOP MONDAY AFTERNOON
BUT CONFIDENCE IS TOO LOW TO MENTION THIS FAR OUT.
WINDS WILL GENERALLY REMAIN NEAR OR BELOW 10KT FOR THE PERIOD.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...PUMA
NEAR TERM...SMF/PUMA
SHORT TERM...PUMA
LONG TERM....JEH
AVIATION...50
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AREA FORECAST DISCUSSION
NWS GOODLAND KS
905 PM MDT TUE JUN 11 2013
.UPDATE...
ISSUED AT 901 PM MDT TUE JUN 11 2013
RED FLAG WARNING ALLOWED TO EXPIRE ON TIME.
AT 03Z COLD FRONT EXTENDED FROM NEAR TRENTON NEBRASKA SOUTHWEST
THROUGH SAINT FRANCIS KS TO NEAR BURLINGTON COLORADO. BEHIND THE
FRONT NORTH TO NORTHEAST WINDS GUSTING TO 25 MPH WITH DEWPOINTS
RAPIDLY INCREASING INTO THE 40S TO MID 60S. 01Z HRRR AND TO A
LESSER EXTENT RUC HAVE A PRETTY GOOD HANDLE ON THINGS COMPARED TO
CURRENT OBSERVATIONS SO HAVE FOLLOWED PRETTY CLOSELY. FRONT SHOULD
CLEAR THE EASTERN FORECAST AREA BY 09Z OR SO.
UPDATE ISSUED AT 404 PM MDT TUE JUN 11 2013
ADDED GRAHAM COUNTY TO RED FLAG WARNING BASED ON CURRENT AND
SEVERAL LAST HOURS OF WIND/HUMIDITY OBSERVATIONS.
&&
.SHORT TERM...(THIS AFTERNOON THROUGH WEDNESDAY)
ISSUED AT 108 PM MDT TUE JUN 11 2013
LATEST VISIBLE SATELLITE INDICATES CUMULUS CLOUDS FORMING OVER FAR
NORTHEAST COLORADO EARLY THIS AFTERNOON AHEAD OF AN UPPER LEVEL
SHORT WAVE TROUGH. AT THE SURFACE A LOW PRESSURE WAS LOCATED OVER
FAR NORTHWEST KANSAS WITH A WARM FRONT STRETCHING EAST OF IT OVER
SOUTHERN NEBRASKA. A DRY LINE NOT TOO FAR SOUTH OF THE FRONT
ARCHING OVER FAR NORTHWEST KANSAS THEN EXTENDING SOUTHEAST TO NEAR
HILLY CITY AND HAYS. AS OF EARLY THIS AFTERNOON WINDS ARE STILL
LIGHT OVER MOST OF THE AREA WHERE THE CAP HAS YET TO ERODE.
FOR THE REST OF THE AFTERNOON WINDS SHOULD BEGIN TO INCREASE BY MID
AFTERNOON AS THE CAP ERODES AND ALLOWS THE STRONGER WINDS TO MIX TO
THE GROUND. WITH THE DRY LINE WELL INTO THE AREA BY LATE AFTERNOON
RELATIVE HUMIDITIES BEHIND IT WILL FALL TO AROUND 10 PERCENT. THE
COMBINATION OF GUSTY WINDS AND LOW RELATIVE HUMIDITIES WILL CREATE
HAZARDOUS FIRE WEATHER CONDITIONS FOR MUCH OF THE AREA. SEE THE
FIRE WEATHER SECTION FOR MORE INFORMATION. DURING THE LATTER HALF
OF THE AFTERNOON LIFT INCREASES OVER THE AREA AHEAD OF A MID LEVEL
SHORT WAVE TROUGH. THE LIFT AND MOISTURE WILL BE CO-LOCATED OVER
THE CENTRAL AND EASTERN PART OF THE AREA...WITH LESS MOISTURE TO THE
WEST AND LESS LIFT TO THE EAST. WITH A DEEP DRY LAYER UP TO 500MB
AND MOST UNSTABLE MIXED 1KM CAPE RANGING FROM 500-1500 J/KG...AM
EXPECTING STORM COVERAGE TO BE VERY SPARSE AT BEST THIS AFTERNOON.
THE MAIN THREAT WITH THESE STORMS WILL BE STRONG TO SEVERE WIND
GUSTS THROUGH EARLY EVENING.
THIS EVENING THE LIFT WILL MOVE EAST AHEAD OF THE MID LEVEL TROUGH.
BY MID EVENING THE ENVIRONMENT BECOMES STABLE CAUSING ANY STORMS
TO COME TO AN END. OVERNIGHT A COOLER AIR MASS WILL
MOVE INTO THE AREA.
WEDNESDAY CAPPING AND AN UPPER LEVEL RIDGE WILL KEEP THE AREA DRY.
HIGHS WILL BE SOMEWHAT COOLER THAN YESTERDAY BUT STILL ABOVE NORMAL
AND WINDS WILL BE LIGHT TO BREEZY.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 226 PM MDT TUE JUN 11 2013
WEDNESDAY NIGHT AND THURSDAY THE UPPER RIDGE REMAINS IN PLACE OVER
THE HIGH PLAINS WITH WARM TEMPERATURES EXPECTED TO CONTINUE.
RETURN FLOW AROUND THE SURFACE HIGH PRESSURE AREA OVER THE
NORTHERN PLAINS WILL BRING ADDITIONAL NEAR SURFACE MOISTURE INTO
THE AREA. IN ADDITION TO A DEEPENING LEE SURFACE TROUGH THAT
PROVIDES FOCUS FOR THUNDERSTORMS DEVELOPMENT...A SHORT WAVE TROUGH
AHEAD OF THE MAIN UPPER TROUGH OVER THE PACIFIC NORTHWEST RIDES
UP THROUGH THE BACK SIDE OF THE UPPER RIDGE THURSDAY NIGHT FOR A
CHANCE OF THUNDERSTORMS ACROSS THE FORECAST AREA THURSDAY
AFTERNOON THROUGH THURSDAY NIGHT.
THE SURFACE LOW PRESSURE CENTER AND COLD FRONT MOVES THROUGH THE
FORECAST AREA LATE FRIDAY AS THE RIDGE AXIS MOVES EAST OF THE
REGION AND THE MAIN UPPER TROUGH MOVES ACROSS THE U.S./CANADIAN
BORDER AREA...FLATTENING THE RIDGE ON SATURDAY AND PRODUCING A
DIRTY ZONAL FLOW ACROSS THE CENTRAL HIGH PLAINS REGION THROUGH
SUNDAY. THIS WILL BRING SLIGHTLY COOLER TEMPERATURES AND ANOTHER
ROUND OF THUNDERSTORMS FRIDAY AND SATURDAY AFTERNOON AND EVENING.
ANOTHER RIDGE BEGINS TO AMPLIFY OVER THE ROCKIES BY LATE
SUNDAY...MOVING INTO POSITION OVER THE HIGH PLAINS REGION BY THE
FIRST PART OF NEXT WEEK WITH WARMER TEMPERATURES AND ONLY ISOLATED
THUNDERSTORMS.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING)
ISSUED AT 515 PM MDT TUE JUN 11 2013
KGLD...VFR EXPECTED THROUGH THE PERIOD. SFC LOW IN NORTHEAST
COLORADO WILL MOVE EAST TOWARD KNRN BY 06Z TONIGHT CONTINUING EAST
THROUGH THE REST OF THE TAF PERIOD. SOUTHWEST WINDS GUSTING 30KTS
AT TAF ISSUANCE WILL VEER TO THE NORTHWEST AT 15G23KTS BY 03Z THEN
SLOWLY VEER TO THE NORTH/NORTHWEST DURING THE MORNING WEDNESDAY
AND FINALLY NORTHEAST THEN EAST FROM LATE MORNING THROUGH THE REST
OF THE TAF PERIOD. SOME WIND GUSTS TO 20KTS EXPECTED AROUND 15Z
BEFORE SLOWLY SUBSIDING THROUGH THE REST OF THE TAF PERIOD AS SFC
HIGH MOVES INTO THE AREA.
KMCK...MESOSCALE SITUATION SIMILAR TO KGLD. HOWEVER...POST FRONTAL
STRATUS EXPECTED BEHIND THE SFC LOW AFTER 06Z WITH POSSIBLE CIGS
AROUND 200 FT FROM 09Z-13Z BEFORE BECOMING SCATTERED AND SLOWLY
IMPROVING ABOVE 3K FT BY 18Z. WINDS VARIABLE AND POSSIBLY GUSTY AT
TAF ISSUANCE BUT WILL BECOME NORTHWEST AROUND 12KTS BY 06Z WITH
GUSTS 20-25KTS AFTER 15Z AND CONTINUING THROUGH 22Z BEFORE VEERING
TO THE NORTHEAST WITH SPEEDS AROUND 10KTS.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...99
SHORT TERM...JTL
LONG TERM...LOCKHART
AVIATION...99
AREA FORECAST DISCUSSION
NWS CARIBOU ME
1030 PM EDT TUE JUN 11 2013
.SYNOPSIS...
LOW PRESSURE WILL TRACK INTO THE GULF OF MAINE TONIGHT THEN EXIT
ACROSS SOUTHERN NOVA SCOTIA LATE WEDNESDAY. HIGH PRESSURE WILL
BUILD OVER THE AREA THURSDAY.&&
.NEAR TERM /THROUGH WEDNESDAY/...
UPDATE 2220L: PRECIP HAS REACHED FAR NRN AREAS ATTM BUT ARE SEEING
SOME DECREASE ACROSS THE FAR SRN AND WRN AREAS. EXPECT THESE AREAS
TO FILL BACK IN LATER TNGT INTO WED BUT FOR NOW HAVE ADJUSTED POPS
ACCORDINGLY. ALSO...W/ AN OVERALL SHIFT OF THE MORE SIGNIFICANT
RAINFALL FURTHER N...HAVE ADJUSTED 6 HRLY AND STORM TOTAL QPF UP A
BIT ACROSS THE N AS WELL...
UPDATE 1900L: PRECIP SPREADING INTO FAR NRN AREAS ATTM SO HAVE ADJUSTED
POPS ACCORDINGLY. ALSO ADDED PATCHY FOG ACROSS THE REGION DURING
THE OVRNGT HRS.
PREV DISC: MAIN CHALLENGES WILL BE QPF AND PLACEMENT.
THE FLOOD WATCH FOR THE CENTRAL AND DOWNEAST AREAS HAS BEEN
DROPPED AS MAJOR FLOODING NOT EXPECTED/THIS EVENT. SO FAR, STORM
TOTALS HAVE BEEN 0.25 TO AROUND 0.50 FROM THE CENTRAL HIGHLANDS
DOWN TO THE COAST AND THIS HAS BEEN MAINLY INTERIOR DOWNEAST AND
COAST. FURTHER NORTH, AMOUNTS OF 005 TO 0.10 MAINLY FROM HOULTON TO
MILLINOCKET W/SOME ISOLATED AREAS OF UP TO 0.25 SUCH AS KNOWLES
CORNER DUE TO SOME CONVERGENCE. 18Z RADAR HAD LARGE AREA OF
MAINLY LIGHT RAIN ACROSS NORTH-CENTRAL AREAS ALIGNING W/A THETA E
AXIS STRETCHING FROM NEW BRUNSWICK BACK ACROSS WSW MAINE. ANOTHER
AREA OF RAIN DOWN ACROSS DOWNEAST AND EASTERN AREAS LIFTING NORTH.
THIS AREA WILL MOVE INTO A MORE FAVORABLE ENVIRONMENT AND CONVERGE
WITH THE AREA ACROSS THE NORTH CENTRAL REGION. FURTHER NORTH
ACROSS THE CROWN OF MAINE, SUBSIDENCE FROM THE UPPER RIDGE IS
HOLDING PRECIP SHIELD AT BAY.
LOW PRES AT THE SFC WILL MOVE INTO THE GULF OF MAINE AND WILL STRENGTHEN
TONIGHT INTO WEDNESDAY. THE LATEST RUC AND HRRR HANDLE THIS WELL
AND LEANED CLOSE TO THIS BLEND INTO TONIGHT. THEREFORE, RAIN IS
EXPECTED TO FILL IN TONIGHT AS THE LOW MOVES EAST. LLVL CONVERGENCE
AND FORCING AT THE MID LEVELS WILL AID IN ENHANCING AND EXPANDING
THE RAINFALL. ATTM, PUSHED POPS UP TO NEAR 100% ACROSS THE WESTERN
AROOSTOOK AND NW PISCATAQUIS REGION TO MATCH UP W/THE RADAR TRENDS
AND RUC PLACEMENT. AS LOW PRES LIFTS ACROSS THE GULF OF MAINE
TONIGHT INTO WEDNESDAY, THE RAIN SHIELD WILL PIVOT SOUTHWARD AS
NORTHERN AND WESTERN AREAS GET UNDER NVA AND LESS FORCING. THE BEST
CONVERGENCE AND FORCING WILL BE ACROSS THE INTERIOR DOWNEAST AND
EASTERN AREAS ON WEDNESDAY AS DEPICTED WELL BY THE ECMWF AND NOW
THE GFS. AN AREA OF ENHANCED RAINFALL IS EXPECTED IN THESE AREAS
AS THE 700MBS LOW MOVES ACROSS THE REGION W/FRONTOGENETICAL
FORCING SETTING UP. DECIDED TO LEAN W/THE NERFC QPF TO ACCOUNT FOR
THIS THINKING W/AND ADDITIONAL 0.75 INCHES OF RAINFALL FROM
12-00Z. RAINFALL WILL BEGIN TO WIND DOWN LATER IN THE AFTERNOON AS
THE LOW GETS CAPTURED AND PULLS FURTHER EAST ACROSS THE SOUTHERN
TIP OF NOVA SCOTIA. NORTHERN AND WESTERN AREAS WILL DRY OUT W/RAIN
ENDING.
TEMPERATURES TONIGHT WILL BE HELD DUE TO THE CLOUDS AND RAIN
MAINLY RUNNING IN THE 50S CWA WIDE. COOLER FOR WEDNESDAY USING A
BLEND OF THE NAM12/GMOS AND ECMWFMOS WHICH SHOWED LOW TO MID 60S
NORTH AND WEST AND UPPER 50S TO AROUND 60S CENTRAL AND DOWNEAST
AREAS. A NE WIND PICKING UP AT 10 TO 20 MPH ON WEDNESDAY ON
BACKSIDE OF THE LOW WILL AID IN THE COOLER TEMPERATURES.&&
.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY/...
LOW PRESSURE NEAR SOUTHERN NOVA SCOTIA CONTINUES TO MOVE OFF TO
THE EAST AT THE BEGINNING OF THIS PERIOD WHILE WEAK HIGH PRESSURE
BUILDS IN OVER THE STATE EARLY THURSDAY. LOW PRESSURE IS THEN
EXPECTED TO PASS TO THE SOUTH FRIDAY. WILL BLEND THE
NAM...GFS...SREF AND ECMWF FOR POPS AND QPF WITH HIGHEST POPS
EXPECTED SOUTH FRIDAY. FOR WIND GRIDS WILL BLEND THE NAM12 AND
GMOS. WILL USE 150 PERCENT OF SUSTAINED WIND SPEED FOR GUSTS.
TEMPERATURE INITIALIZED WITH THE GMOS. WILL ADD 3 DEGREES FOR
MINIMUM TEMPERATURE AND 2 DEGREES TO MAXIMUM TEMPERATURE TO
COMPENSATE FOR LOW GMOS BIAS LAST SEVERAL DAYS.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
LOW PRESSURE WILL BE PULLING AWAY FROM THE FORECAST AREA FRIDAY
NIGHT, FOLLOWED BY A RIDGE OF HIGH PRESSURE. THE HIGH WILL MOVE
ACROSS THE EASTERN CONUS SATURDAY AND SUNDAY, LEADING TO A MOSTLY
DRY WEEKEND. HOWEVER, PRECIPITATION RETURNS EARLY NEXT WEEK AS A
SERIES OF DISTURBANCES MOVES THROUGH THE NEARLY ZONAL FLOW ALOFT.
TEMPERATURES WILL BE SEASONABLE THROUGH THE PERIOD.
&&
.AVIATION /03Z WEDNESDAY THROUGH SUNDAY/...
NEAR TERM: VFR ACROSS THE FAR NORTHERN TERMINALS THIS EVENING
DROPPING TO MVFR TONIGHT INTO EARLY WEDNESDAY. IMPROVEMENT TO VFR
IS EXPECTED BY WEDNESDAY NIGHT INTO THURSDAY. FROM KHUL DOWN INTO
KBGR AND KBHB, MVFR TO IFR TONIGHT INTO WEDNESDAY AFTERNOON AND
THEN CONDITIONS LOOK LIKE THEY WILL IMPROVE TO VFR WEDNESDAY NIGHT
INTO THURSDAY. THERE IS POTENTIAL FOR SOME MVFR AND POSSIBLY IFR
BY FRIDAY W/A ESE FLOW SETTING UP. VFR EXPECTED FOR THE WEEKEND.
SHORT TERM: VFR CONDITIONS EXPECTED THURSDAY AND FRIDAY. ONLY
EXCEPTION IS KBGR AND KBHB WHERE IFR/MVFR CONDITIONS POSSIBLE
THURSDAY NIGHT INTO FRIDAY.
&&
.MARINE...
NEAR TERM: UPDATE 1900L: ADDED AREAS OF FOG INTO WED AM...
PREV DISC: SCA FOR HAZARDOUS SEAS IN PLACE. A SOUTHERLY SWELL IS
OUT THERE ATTM W/WAVES OF 3 FT AND A 8-9 SECOND PERIOD. A BRIEF
WINDOW(3-6HR) OF WINDS APCHG 25 KTS IS EXPECTED ON WEDNESDAY ON
THE BACKSIDE OF THE LOW. WINDS WILL COME DOWN AS THE LOW PULLS
TOWARD NOVA SCOTIA. WAVES HEIGHTS CLIMBING ATTM TO 5-6 FT PER THE
LATEST OBS. DECIDED TO BRING WAVES UP A FOOT TO HIT 7-8 FT W/THE
LONG SOUTHERLY FETCH. THE LATEST SWAN GUIDANCE HAD THIS HANDLED WELL.
SHORT TERM: FOR WIND WILL USE A 50/50 BLEND OF THE NAM12 AND
GFS40. HAVE LOWERED SUSTAINED WIND SPEED BY 20 PERCENT TO
COMPENSATE FOR MARINE LAYER. FOR GUST SPEED WILL USE 125 PERCENT
OF SUSTAINED WINDS. FOR WAVES: NORTHEAST WIND WAVES PRIMARY WAVE
GROUP THURSDAY AND FRIDAY WITH SECONDARY SOUTHERLY SWELL OUT OF
SOUTH (2 FEET/9 SECONDS). WILL USE NAM/SWAN TO INITIALIZE WAVE
GRIDS AND WILL REDUCE WAVE HEIGHT 1 FOOT TO COMPENSATE FOR HIGH
BIAS EXPECTED FROM NAM WINDS.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
MARINE...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 2 AM EDT
THURSDAY FOR ANZ050>052.
&&
$$
NEAR TERM...KHW/HEWITT
SHORT TERM...MIGNONE
LONG TERM...HASTINGS
AVIATION...KHW
MARINE...KHW/HEWITT/MIGNONE
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
424 PM EDT MON JUN 10 2013
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 422 PM EDT MON JUN 10 2013
WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW A RIDGE OVER THE SRN
ROCKIES EDGING OUT INTO THE SRN PLAINS. TO THE N...A WELL DEFINED
MID-LEVEL LOW WAS OVER SASKATCHEWAN. STRONG WRLY FLOW WAS NOTED BTWN
THESE TWO FEATURES ALONG THE U.S./CANADIAN BORDER WITH A 110KT UPPER
JET ANALYZED BY THE RUC. THIS JET STREAK AND ASSOCIATED SHORTWAVE
WILL BE THE NEXT FEATURE OF INTEREST AS IT SHIFTS THRU THE UPPER
GREAT LAKES TUE. ANOTHER SHORTWAVE HAS LIFTED THRU NRN ONTARIO
TODAY. TAIL END OF SHORTWAVE COMBINED WITH DAYTIME HEATING AND LAKE
BREEZE CONVERGENCE HAS RESULTED IN ISOLD/SCT SHRA DEVELOPING OVER
WRN UPPER MI TODAY. SO FAR...NO THUNDER EVEN THOUGH LATEST SPC
MESOANALYSIS SHOWS SBCAPE/MLCAPE UPWARDS OF 1000/500J/KG OVER THE
INTERIOR WRN UPPER MI.
DIURNALLY DRIVEN SHRA AND MAYBE YET ISOLD TSRA OVER WRN UPPER MI
WILL DISSIPATE THIS EVENING WITH LOSS OF DAYTIME HEATING. AFTER SHRA
DISSIPATE...EXPECT A TREND TOWARD CLR/PARTLY CLOUDY SKIES FOR A TIME
TONIGHT TO ALLOW FOR SOME FOG TO DEVELOP UNDER MID LEVEL DRYING AND
LIGHT/CALM WIND. FOG WILL BE MOST LIKELY WHERE SOME RAIN HAS FALLEN
THIS AFTN. LATER TONIGHT...AFOREMENTIONED JET STREAK/SHORTWAVE AND
ASSOCIATED DEEP LAYER FORCING WILL BE APPROACHING THE AREA. GIVEN
THAT SHRA/TSRA HAVE BEEN OCCURRING ALL DAY WITH FEATURE...IT APPEARS
CHC POPS ARE WARRANTED OVER WRN LAKE SUPERIOR INTO NW UPPER MI
LATE TONIGHT.
INTERESTING FCST FOR TUE WITH REGARD TO TSTM POTENTIAL. MUCH WILL
DEPEND ON TIMING OF JET STREAK/SHORTWAVE AND DEGREE OF INSTABILITY.
FROM A LARGER SCALE STANDPOINT...THE WNW FLOW PATTERN IS ONE WHICH
OFTEN SUPPORTS SVR STORMS OVER UPPER MI. WITH UPPER LEVEL WIND MAX
PASSING ACROSS THE AREA...DEEP LAYER SHEAR TUE IS ON THE ORDER OF
60-70KT. FORTUNATELY...WITH MLCAPE UP AROUND 500J/KG FROM THE NAM
AND ONLY A FEW HUNDRED FROM THE GFS...INSTABILITY WILL BE LACKING
TO TAKE ADVANTAGE OF THE STRONG DEEP LAYER SHEAR...AND FORCING WILL
BE PASSING THRU EARLIER IN THE DAY AND MOSTLY LIKELY NOT IN CONCERT
WITH PEAK HEATING. THE NAM REPRESENTS THE SLOWER END OF THE SPECTRUM
ON THE PROGRESSION TUE WHILE THE GFS IS ON THE FASTER SIDE. THE GEM
OFFERS A GOOD COMPROMISE WITH TIMING AND WILL BE FAVORED. PLAN WILL
BE TO CARRY SCHC/LOW CHC POPS ACROSS THE AREA FROM WNW TO ESE TUE.
BEST CHC OF SHRA/TSRA WILL BE OVER THE SCNTRL/SE WHERE LAKE BREEZE
OFF LAKE MI WILL PROVIDE ENHANCED LOW-LEVEL FORCING. PRONOUNCED
MIDLEVEL DRYING SURGING INTO THE AREA WILL BRING AN END TO
SHRA/TSRA FROM W TO E DURING THE AFTN...AND SKIES WILL LIKELY BECOME
SUNNY/MOSTLY SUNNY OVER THE W. IF FOR SOME REASON PROGRESSION IS
SLOWER TUE AND INSTABILITY BUILDS HIGHER THAN CURRENTLY EXPECTED...
THERE MAY BE A FEW SVR STORMS TO DEAL WITH OVER THE SCNTRL/SE.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 422 PM EDT MON JUN 10 2013
NO SIGNIFICANT WEATHER SYSTEMS...AND NEAR NORMAL TEMPERATURES WILL
BE THE RULE FOR MUCH OF THIS LONG TERM PERIOD. EXPECT A FEW
LINGERING SHOWERS WILL BE POSSIBLE OVER FAR E AND SE CORNERS OF THE
CWA.
THE CURRENT LOW ACROSS CENTRAL CANADA WILL OPEN UP AND SWING AROUND
THE SET RIDGE OF HIGH PRESSURE OVER MUCH OF THE SOUTHERN U.S...AND
MOVE TO SD/NE BY WEDNESDAY MORNING. THIS WAVE WILL LINE UP WITH A
SECONDARY WAVE SWINGING AROUND THE LARGE LOW OVER NE CANADA ACROSS
THE UPPER GREAT LAKES WEDNESDAY NIGHT INTO THURSDAY MORNING. EVEN
WITH ALL OF THAT...UPPER MI MAY END UP DRY WEDNESDAY NIGHT INTO
THURSDAY. DID ADD A JUST A FEW SHOWERS FOR FAR E UPPER MI /FIRE
ZONES/ THURSDAY AFTERNOON. THE MAIN RESULT WILL BE ADDITIONAL
CLOUDS. KEPT THE MENTION OF PATCHY FOG OVER THE GREAT LAKES THROUGH
THURSDAY EVENING...BEFORE HIGH PRESSURE SINKS IN FROM THE NW. 850MB
TEMPS OFF THE ECMWF STAY AROUND 8C FROM THURSDAY THROUGH MUCH OF
FRIDAY. EXPECT TEMPS TO COOL BACK INTO THE 60S NEAR LAKE SUPERIOR
BOTH THURSDAY AND FRIDAY...EVEN IN THE UPPER 50S F RIGHT ALONG THE
SHORELINE.
WITH THE 500MB TROUGHS SHIFTING TO OUR E AND A HIGH AMPLITUDE RIDGE
STRETCHING FROM TX THROUGH CENTRAL CANADA...EXPECT NW FLOW TO RETURN
ALOFT. HIGH TEMPS SHOULD RISE INTO THE MID AND UPPER 70S FOR THE
UPCOMING WEEKEND. THE WEEKEND STILL LOOKS UP IN THE AIR...WITH A
SMALL CHANCE OF PRECIP SATURDAY AFTERNOON WEST...LINGERING ACROSS
THE ENTIRE AREA THROUGH SUNDAY. THERE REMAINS ENOUGH DIFFERENCES TO
NOT GO HIGHER THAN CHANCE...WITH MODERATE TO LOW CONFIDENCE IN THE
ONGOING FORECAST FROM SATURDAY THROUGH MONDAY. THE EARLIER 10/00Z
RUN OF THE ECMWF AND 10/12Z RUN OF THE GFS BOTH PAINTED A GOOD
AMOUNT OF PRECIP FOR THE CWA...WHICH WHEN BLENDED RESULTED IN HIGH
CHANCE POPS FOR MONDAY. SINCE THEN OF COURSE THE 01/12Z RUN OF THE
ECMWF HAS COME IN MAINLY DRY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 138 PM EDT MON JUN 10 2013
WITH INCREASING INSTABILITY...SCT SHRA WILL CONTINUE TO DEVELOP OVER
WRN UPPER MI THIS AFTN. THESE SHRA WILL MAINLY AFFECT THE AREAS
AROUND KIWD/KSAW BEFORE THEY DISSIPATE BY 00Z WITH WANING DAYLIGHT.
WITH UNCERTAINTY IN WHETHER A SHRA WILL ACTUALLY IMPACT EITHER
TERMINAL...ONLY VCSH WILL BE UTILIZED. OTHERWISE...VFR CONDITIONS
WILL PREVAIL AT KIWD/KCMX/KSAW INTO THE EARLY EVENING. A WEAK HIGH
PRES WILL MOVE IN THIS EVENING...AND WITH LIGHT WINDS AND JUST SOME
PATCHY HIGHER CLOUDS...SETUP LOOKS GOOD FOR SOME FOG TO FORM WITH
IFR CONDITIONS APPEARING LIKELY. DISTURBANCE RAPIDLY APPROACHING
FROM THE W MAY BRING VCNTY SHRA TO KCMX LATE TONIGHT AND TO
KIWD/KSAW TUE MORNING. INCREASE IN CLOUDS SHOULD CAUSE RADIATION FOG
TO DISSIPATE AT KCMX LATE TONIGHT...BUT WILL LIKELY NEED TO WAIT
UNTIL AFTER SUNRISE AT KIWD/KSAW FOR FOG TO DISSIPATE.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 422 PM EDT MON JUN 10 2013
WEAK PRES GRADIENT WILL RESULT IN WINDS GENERALLY 15KT OR LESS THRU
THE WEEK. SLIGHTLY STRONGER WINDS UP TO 20KT MAY OCCUR OVER PORTIONS
OF CNTRL/ERN LAKE SUPERIOR LATE WED NIGHT/THU IN ADVANCE OF HIGH
PRES BUILDING TOWARD LAKE SUPERIOR. WITH RAINFALL THAT OCCURRED
TODAY OVER WRN LAKE SUPERIOR...THERE WILL PROBABLY BE SOME FOG
PATCHES OVER WRN LAKE SUPERIOR TONIGHT. IF SO...FOG PATCHES WILL
SHIFT TO ERN LAKE SUPERIOR TUE AS WINDS BECOME WESTERLY. THE PATCHY
FOG MAY THEN LINGER THU.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...ROLFSON
LONG TERM...KF
AVIATION...ROLFSON
MARINE...ROLFSON
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
140 PM EDT MON JUN 10 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 412 AM EDT MON JUN 10 2013
00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW AN UPR RDG
EXTENDING FM NW ONTARIO THRU THE GREAT LKS TO THE MID ATLANTIC
COAST. THERE ARE 2 CLOSED LOWS UPSTREAM...ONE MOVING THRU THE MID MS
RIVER VALLEY AND ANOTHER OVER SASKATCHEWAN TO THE N OF MEAN RDG OVER
THE WRN CONUS. A SHRTWV IS MOVING INTO NE MN BTWN THE 2 CLOSED LOWS
AND GENERATING AN AREA RA OVER FAR NW LK SUP AND NE MN AS THE DPVA/
DEEP LYR QVECTOR CNVGC AHEAD OF THIS FEATURE INTERACTS WITH DEEP
MSTR SHOWN ON THE 00Z INL RAOB. BUT SINCE THE DEEPER MSTR AND
FORCING ASSOCIATED WITH THE CLOSED LO IN THE MID MS RIVER VALLEY ARE
TO THE S OF UPR MI...THERE IS NO DYNAMIC SUPPORT FOR PCPN OVER UPR
MI...WITH AN ABSENCE OF SGNFT RADAR RETURNS OVER THE AREA DESPITE
MOCLDY SKIES. THE CLDS HAVE LIMITED THE DIURNAL FALL OF TEMP...WITH
MOST PLACES REPORTING TEMPS IN THE 50S TO LO 60S EARLY THIS MRNG.
SOME BREAKS IN THE CLDS ARE MOVING NE INTO UPR MI FM WI. THICKER
CLDS/SOME ISOLD -SHRA ARE MOVING N THRU LWR MI.
MAIN FCST CONCERNS IN THE SHORT TERM INVOLVE PCPN CHCS ASSOCIATED
WITH SHRTWV NOW MOVING THRU NE MN.
TDAY...SHRTWV IN NE MN IS PROGGED TO LIFT NEWD INTO NW ONTARIO ON
THE SE FLANK OF NEARLY STNRY CLOSED LO OVER SASKATCHEWAN. DPVA/H85-5
QVECTOR CNVGC ASSOCIATED WITH THIS FEATURE ARE PROGGED TO BRUSH THE
NW CWA INTO THIS AFTN BEFORE THE SHRTWV LIFTS FARTHER TO THE NE AND
GIVES WAY TO DNVA/DEEP LYR QVECTOR DVGC/MID LVL DRYING. MODELS SHOW
BULK OF PCPN ACCOMPANYING THIS SHRTWV PASSAGE REMAINING TO THE NW OF
EVEN THE KEWEENAW. SO OPTED TO CUT POPS TO NO HIER THAN SCHC THIS
MRNG OVER THE LAND CWA. DID ADD SCHC POPS OVER THE E TO ACCOUNT FOR
ISOLD -SHRA MOVING N THRU NRN LWR MI. EVEN AFT THE DYNAMIC SUPPORT
SWINGS TO THE N THIS AFTN...BULK OF RECENT NUMERICAL GUIDANCE IS
GENERATING QPF OVER MAINLY THE INTERIOR W HALF OF THE CWA AS DAYTIME
HEATING DESTABILIZES THE ATMOSPHERE AND LK BREEZE BNDRYS PROVIDE
SOME LLVL FOCUS. TENDED TO RAISE FCST MAX TEMPS A FEW DEGREES TO
ACCOUNT FOR SOME BREAKS IN THE CLDS MOVING NE FM WI AND ABSENCE OF
DYNAMIC FORCING OVER MOST OF THE FA. THE ONLY EXCEPTION WAS THE E...
WHERE MORE CLDS STREAMING NWD THRU LWR MI MIGHT HOLD DOWN THE
DIURNAL TEMP INCRS. EVEN THOUGH WARMING/DRYING ABV H6 WITH THE
ARRIVAL OF THE NEGATIVE DYNAMICS SETS IN AFT 18Z AND WL LIMIT
POTENTIAL FOR DEEP CNVCTN...MODIFIED NAM FCST SDNG FOR THE INTERIOR
W FOR SFC T/TD OF 75/57 YIELDS SBCAPE NEAR 450 J/KG AND KINX OF 33.
GOING CHC POPS/SCHC OF TS LOOKS TO BE IN PRETTY GOOD ORDER.
TNGT...IN THE ABSENCE OF ANY DYNAMIC SUPPORT...EXPECT DIURNAL SHRA
OVER MAINLY THE W HALF TO DIMINISH THIS EVNG WITH LOSS OF DAYTIME
HEATING. ALTHOUGH ANOTHER SHRTWV IS PROGGED TO RACE EWD ALONG THE
CNDN BORDER THRU TNGT IN THE FAST WLY FLOW ON THE SRN FLANK OF THE
SASKATCHEWAN CLOSED LO AND APRCH THE NW CWA LATER WITH SOME
DPVA/DEEP LYR QVECTOR CNVGC...FAIRLY DRY MID LVLS/LLVL ACYC FLOW/
ABSENCE OF ANY DIURNAL HEATING WL LIMIT ACCOMPANYING POPS...
ESPECIALLY SINCE THE FOCUS OF THE ASSOCIATED FORCING IS FCST TO PASS
TO THE N. DID RETAIN SOME CHC POPS OVER THE NW CWA TO ACCOUNT FOR
THIS DISTURBANCE. OTRW...EXPECT SOME FOG TO FORM OVER THE INTERIOR
WITH THE MID LVL DRYING/LGT WINDS...ESPECIALLY IN AREAS WHERE SOME
RA MIGHT FALL THIS AFTN AND FURTHER MOISTEN THE LLVLS.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 412 AM EDT MON JUN 10 2013
LARGER SCALE PATTERN BY TUESDAY INDICATES STRING OF TROUGHS ACROSS
CANADA AND TROUGHING OVER NORTHWEST CONUS AND NORTHEAST CONUS.
SHALLOW RIDGING IS ANCHORED OVER SOUTH CENTRAL CONUS. THROUGH REST
OF THE WEEK TROUGHING OVER CANADA SPLITS WITH RIDGING ATTEMPTING TO
BUILD INTO CANADIAN PRAIRIES. EVENTUALLY THIS RIDGE MOVES EAST INTO
NORTHERN PLAINS AND UPPER GREAT LAKES BY START OF NEXT WEEKEND. YET
ANOTHER TROUGH WILL THEN SWING BACK ACROSS UPPER LAKES TO CLOSE THE
WEEKEND. OVERALL PATTERN WILL NOT BRING MUCH RAIN TO UPPER LAKES BUT
IT ALSO SHOULD NOT BE THAT COLD EITHER AS BULK OF COLDER AIR STAYS
LOCKED UP OVER WESTERN AND EASTERN CANADA CLOSER TO MORE PERSISTENT
TROUGHING. TEMPS INLAND FROM LK SUPERIOR AND NEAR LK MICHIGAN MOST
DAYS WILL BE AT OR ABOVE NORMAL. TEMPS ALONG LK SUPERIOR WILL BE AT
OR SLIGHTLY BLO NORMAL MOST OF THE TIME SINCE PREVAILING WINDS WILL
BE ONSHORE. WARMEST DAYS WILL BE TUESDAY AND AGAIN ON SATURDAY WITH
MOST AREAS WELL INTO THE 70S. COOLEST DAY THIS WEEK FOR ALL AREAS
SHOULD BE ON THURSDAY WHEN TEMPS ALONG LK SUPERIOR WILL LIKELY STAY
IN THE 50S.
WEAK SHORTWAVE TROUGH AND POCKET OF H85-H7 MOISTURE SWINGS ACROSS
WESTERN AND CENTRAL CWA ON TUESDAY MORNING THEN OVR EASTERN CWA
DURING AFTN HOURS. THOUGH SHARPEST LIFT IN FORM OF H85-H7 Q-VECTOR
CONVERGENCE IMPACTS LK SUPERIOR AND ISLE ROYALE/KEWEENAW PENINSULA
THROUGH MIDDAY...RIBBON OF LIFT CROSSES REST OF CWA AS WELL. WEAK
FORCING AND SUBTLE MOISTENING POINTS TO LOW CHANCE POPS. BUT...KIND
OF SIMILAR TO TODAY...COULD SEE ISOLD DAYTIME SHRA AND EVEN TSRA AS
SFC CAPES POP UP TO 300-500J/KG OVR SCNTRL IN THE AFTN. H7-H5 WINDS
45-55KT RESULTING IN DEEP LAYER SHEAR OVR 30 KTS. DO NOT EXPECT THERE
TO BE ENOUGH INSTABILITY TO TAKE ADVANTAGE OF THE STRONGER SHEAR
THOUGH SO DO NOT EXPECT ANY STRONG STORMS. DEEP DRYING IN H7 LAYER
QUICKLY ENDS ANY SHRA/TSRA BY LATE TUE AFTN. H7 DRYING AND NEUTRAL
HEIGHTS SHOULD KEEP CONDITIONS DRY THROUGH REST OF TUESDAY NIGHT.
ON WEDNESDAY...SHORTWAVE TROUGH SLIDES FROM ROCKIES TOWARD UPPER
MISSISSIPPI RIVER VALLEY. SFC LOW/WARM FRONT SET UP FROM NEB INTO
NORTHERN IL WHILE H85 WARM FRONT IS NOT MUCH FARTHER THAN THAT.
EDGE OF H7 MOISTURE MIGHT MAKE IT INTO NORTHERN WI...BUT SINCE 1-6KM
MUCAPE IS BARELY INTO SOUTHERN MN AND CNTRL WI...HAVE HARD TIME
THINKING THAT THE INCREASE IN H7 MOSITURE WOULD RESULT IN NOTHING
MORE THAN A FEW SPRINKLES OUT OF A SCT-BKN MID CLOUD DECK. NOT
WORTH PUTTING ANY POPS INTO SOUTHERN CWA. OTHER THING TO WATCH ON
WEDNESDAY IS SHORTWAVE TIED INTO NORTHERN STREAM TROUGH PUSHING INTO
ONTARIO. TREND IS FOR WAVE TO BE STRONGER...BUT MAJORITY OF MODELS
KEEP WAVE ON WNW-ESE TRACK OVER NORTHERN LK SUPERIOR IN THE MORNING
AND OVER ONTARIO EAST OF SAULT STE MARIE BY AFTN. SFC BASED
INSTABILITY AND STEEPER H7-H5 LAPSE RATES SHOULD SPUR ON SCATTERED
SHRA/TSRA NORTH AND EAST OF LK SUPERIOR WITH DAYTIME HEATING. ONLY
THE GEM-NH SHOWS THE WAVE DIGGING ENOUGH SOUTH TO HAVE ANY QPF OVR
UPR MICHIGAN THOUGH AND THAT IS ONLY OVR FAR EAST CWA. MAJORITY
RULES FOR NOW SO HAVE NOT PUT ANY POPS IN OVER THE EAST. MAX TEMPS
MAY SHOW VARIATION CLOSER TO LK SUPERIOR AS LAKE COOLING IS ENHANCED
BY AFTN WITH DEVELOPING NORTH GRADIENT FLOW. MAY SEE TEMPS QUICKLY
RISE WEDNESDAY MORNING CLOSER TO LK SUPERIOR THEN FALL OFF IN THE
AFTN. FARTHER INLAND...EXPECT ANOTHER DAY WITH HIGHS INTO THE 70S.
SHORTWAVE PASSAGE RESULTS IN H85-H7 WINDS VEERING MORE NORTH LATER
WEDNESDAY NIGHT INTO THURSDAY. H85 THERMAL TROUGH ALSO PRESENT. NOT
EXPECTING ANY SHRA AS FORCING IS MINIMAL...BUT MAY SEE DECENT CLOUD
COVER IN THE MORNING. BY AFTN...H85 RH PROGS SHOWING LAKE
STABILIZING SIGNAL WITH MINIMUM RH SHOWING UP OVR LK SUPERIOR AFT
18Z. PROBABLY WILL SEE CLEARING DEVELOP CLOSER TO LK SUPERIOR AND
OVER EAST DUE TO STABILIZING FLOW. EVEN WITH CLEARING WILL BE COOL
DAY ALONG LK SUPERIOR AS MOST LOCATIONS STAY IN THE 50S WITH STIFF
NORTHERLY WINDS. INLAND TEMPS WILL BE IN THE UPR 60S TO PERHAPS
LOWER 70S. HIGH PRESSURE BUILDS ACROSS THURSDAY NIGHT THROUGH
FRIDAY AND NOW EVEN THROUGH MOST OF FRIDAY NIGHT. MOSTLY CLEAR SKIES
WILL PREVAIL AND GIVEN TREND OF HIGH STAYING AROUND LONGER...FRIDAY
NIGHT NOW LOOKING GENERALLY FREE OF ANY SHRA/TSRA EXCEPT FAR WEST
CWA.
WEEKEND FORECAST MUDDLED AS MID CONUS RIDGE FLATTENS OUT FROM
NORTHERN PLAINS TO UPPER GREAT LAKES. STRONGER SHORTWAVE TROUGHS
CUTTING THROUGH THE RIDGE FORECAST TO BE OVR CNTRL CANADA AND OVR
THE MIDDLE MISSISSIPPI RIVER VALLEY. TALKING DAY 6 AND 7 SO HARD TO
GET TOO HUNG UP ON THESE TYPE OF DETAILS YET. OVERALL THEME THOUGH
IS SLOWER ARRIVAL OF SHRA/TSRA CHANCES AND/OR A GENERAL LACKING
FOCUS FOR SHRA/TSRA. CONSENSUS POPS IN THE LOW CHANCE RANGE USED BUT
DID PULL POPS OVER EASTERN CWA ON SATURDAY AS THAT AREA IS IN CLOSER
PROXIMITY OF STUBBORN SFC RIDGING. TEMPS FOR NEXT WEEKEND SHOULD BE
SIMILAR TO READINGS THIS WEEK WITH HIGHS MAINLY IN THE 70S AND
POSSIBLY WARMER IF THERE ARE LESS CLOUDS/SHRA/TSRA.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 138 PM EDT MON JUN 10 2013
WITH INCREASING INSTABILITY...SCT SHRA WILL CONTINUE TO DEVELOP OVER
WRN UPPER MI THIS AFTN. THESE SHRA WILL MAINLY AFFECT THE AREAS
AROUND KIWD/KSAW BEFORE THEY DISSIPATE BY 00Z WITH WANING DAYLIGHT.
WITH UNCERTAINTY IN WHETHER A SHRA WILL ACTUALLY IMPACT EITHER
TERMINAL...ONLY VCSH WILL BE UTILIZED. OTHERWISE...VFR CONDITIONS
WILL PREVAIL AT KIWD/KCMX/KSAW INTO THE EARLY EVENING. A WEAK HIGH
PRES WILL MOVE IN THIS EVENING...AND WITH LIGHT WINDS AND JUST SOME
PATCHY HIGHER CLOUDS...SETUP LOOKS GOOD FOR SOME FOG TO FORM WITH
IFR CONDITIONS APPEARING LIKELY. DISTURBANCE RAPIDLY APPROACHING
FROM THE W MAY BRING VCNTY SHRA TO KCMX LATE TONIGHT AND TO
KIWD/KSAW TUE MORNING. INCREASE IN CLOUDS SHOULD CAUSE RADIATION FOG
TO DISSIPATE AT KCMX LATE TONIGHT...BUT WILL LIKELY NEED TO WAIT
UNTIL AFTER SUNRISE AT KIWD/KSAW FOR FOG TO DISSIPATE.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 412 AM EDT MON JUN 10 2013
AS LO PRES IN THE LOWER GREAT LAKES SHIFTS SLOWLY TO THE E TODAY...
EXPECT E-SE WINDS UP TO 20 KTS TO SLOWLY DIMINISH W-E WITH THE
WEAKENING PRES GRADIENT AND UNDER 15 KTS TONIGHT. DID MAINTAIN
PATCHY FOG OVER MUCH OF THE WESTERN LAKE WHERE SOME SHOWERS HAVE
FURTHER MOISTENED THE LOW LEVELS. THE WEAK PRES GRADIENT WILL
PREVAIL THRU FRI...SO PLAN ON WINDS UNDER 15 KTS TUE THRU FRI.
COULD BE A BRIEF PERIOD OF STRONGER WINDS...UP TO 20 KTS IN
GUSTS...LATE WEDNESDAY NIGHT AND THURSDAY MORNING. RELATIVELY
MOIST AIR OVER THE STILL CHILLY LAKE WATERS WILL RESULT IN
LINGERING FOG PATCHES UNTIL DRIER AIR ARRIVES ON FRI.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...JLA
AVIATION...ROLFSON
MARINE...KC/JLA
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
728 AM EDT MON JUN 10 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 412 AM EDT MON JUN 10 2013
00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW AN UPR RDG
EXTENDING FM NW ONTARIO THRU THE GREAT LKS TO THE MID ATLANTIC
COAST. THERE ARE 2 CLOSED LOWS UPSTREAM...ONE MOVING THRU THE MID MS
RIVER VALLEY AND ANOTHER OVER SASKATCHEWAN TO THE N OF MEAN RDG OVER
THE WRN CONUS. A SHRTWV IS MOVING INTO NE MN BTWN THE 2 CLOSED LOWS
AND GENERATING AN AREA RA OVER FAR NW LK SUP AND NE MN AS THE DPVA/
DEEP LYR QVECTOR CNVGC AHEAD OF THIS FEATURE INTERACTS WITH DEEP
MSTR SHOWN ON THE 00Z INL RAOB. BUT SINCE THE DEEPER MSTR AND
FORCING ASSOCIATED WITH THE CLOSED LO IN THE MID MS RIVER VALLEY ARE
TO THE S OF UPR MI...THERE IS NO DYNAMIC SUPPORT FOR PCPN OVER UPR
MI...WITH AN ABSENCE OF SGNFT RADAR RETURNS OVER THE AREA DESPITE
MOCLDY SKIES. THE CLDS HAVE LIMITED THE DIURNAL FALL OF TEMP...WITH
MOST PLACES REPORTING TEMPS IN THE 50S TO LO 60S EARLY THIS MRNG.
SOME BREAKS IN THE CLDS ARE MOVING NE INTO UPR MI FM WI. THICKER
CLDS/SOME ISOLD -SHRA ARE MOVING N THRU LWR MI.
MAIN FCST CONCERNS IN THE SHORT TERM INVOLVE PCPN CHCS ASSOCIATED
WITH SHRTWV NOW MOVING THRU NE MN.
TDAY...SHRTWV IN NE MN IS PROGGED TO LIFT NEWD INTO NW ONTARIO ON
THE SE FLANK OF NEARLY STNRY CLOSED LO OVER SASKATCHEWAN. DPVA/H85-5
QVECTOR CNVGC ASSOCIATED WITH THIS FEATURE ARE PROGGED TO BRUSH THE
NW CWA INTO THIS AFTN BEFORE THE SHRTWV LIFTS FARTHER TO THE NE AND
GIVES WAY TO DNVA/DEEP LYR QVECTOR DVGC/MID LVL DRYING. MODELS SHOW
BULK OF PCPN ACCOMPANYING THIS SHRTWV PASSAGE REMAINING TO THE NW OF
EVEN THE KEWEENAW. SO OPTED TO CUT POPS TO NO HIER THAN SCHC THIS
MRNG OVER THE LAND CWA. DID ADD SCHC POPS OVER THE E TO ACCOUNT FOR
ISOLD -SHRA MOVING N THRU NRN LWR MI. EVEN AFT THE DYNAMIC SUPPORT
SWINGS TO THE N THIS AFTN...BULK OF RECENT NUMERICAL GUIDANCE IS
GENERATING QPF OVER MAINLY THE INTERIOR W HALF OF THE CWA AS DAYTIME
HEATING DESTABILIZES THE ATMOSPHERE AND LK BREEZE BNDRYS PROVIDE
SOME LLVL FOCUS. TENDED TO RAISE FCST MAX TEMPS A FEW DEGREES TO
ACCOUNT FOR SOME BREAKS IN THE CLDS MOVING NE FM WI AND ABSENCE OF
DYNAMIC FORCING OVER MOST OF THE FA. THE ONLY EXCEPTION WAS THE E...
WHERE MORE CLDS STREAMING NWD THRU LWR MI MIGHT HOLD DOWN THE
DIURNAL TEMP INCRS. EVEN THOUGH WARMING/DRYING ABV H6 WITH THE
ARRIVAL OF THE NEGATIVE DYNAMICS SETS IN AFT 18Z AND WL LIMIT
POTENTIAL FOR DEEP CNVCTN...MODIFIED NAM FCST SDNG FOR THE INTERIOR
W FOR SFC T/TD OF 75/57 YIELDS SBCAPE NEAR 450 J/KG AND KINX OF 33.
GOING CHC POPS/SCHC OF TS LOOKS TO BE IN PRETTY GOOD ORDER.
TNGT...IN THE ABSENCE OF ANY DYNAMIC SUPPORT...EXPECT DIURNAL SHRA
OVER MAINLY THE W HALF TO DIMINISH THIS EVNG WITH LOSS OF DAYTIME
HEATING. ALTHOUGH ANOTHER SHRTWV IS PROGGED TO RACE EWD ALONG THE
CNDN BORDER THRU TNGT IN THE FAST WLY FLOW ON THE SRN FLANK OF THE
SASKATCHEWAN CLOSED LO AND APRCH THE NW CWA LATER WITH SOME
DPVA/DEEP LYR QVECTOR CNVGC...FAIRLY DRY MID LVLS/LLVL ACYC FLOW/
ABSENCE OF ANY DIURNAL HEATING WL LIMIT ACCOMPANYING POPS...
ESPECIALLY SINCE THE FOCUS OF THE ASSOCIATED FORCING IS FCST TO PASS
TO THE N. DID RETAIN SOME CHC POPS OVER THE NW CWA TO ACCOUNT FOR
THIS DISTURBANCE. OTRW...EXPECT SOME FOG TO FORM OVER THE INTERIOR
WITH THE MID LVL DRYING/LGT WINDS...ESPECIALLY IN AREAS WHERE SOME
RA MIGHT FALL THIS AFTN AND FURTHER MOISTEN THE LLVLS.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 412 AM EDT MON JUN 10 2013
LARGER SCALE PATTERN BY TUESDAY INDICATES STRING OF TROUGHS ACROSS
CANADA AND TROUGHING OVER NORTHWEST CONUS AND NORTHEAST CONUS.
SHALLOW RIDGING IS ANCHORED OVER SOUTH CENTRAL CONUS. THROUGH REST
OF THE WEEK TROUGHING OVER CANADA SPLITS WITH RIDGING ATTEMPTING TO
BUILD INTO CANADIAN PRAIRIES. EVENTUALLY THIS RIDGE MOVES EAST INTO
NORTHERN PLAINS AND UPPER GREAT LAKES BY START OF NEXT WEEKEND. YET
ANOTHER TROUGH WILL THEN SWING BACK ACROSS UPPER LAKES TO CLOSE THE
WEEKEND. OVERALL PATTERN WILL NOT BRING MUCH RAIN TO UPPER LAKES BUT
IT ALSO SHOULD NOT BE THAT COLD EITHER AS BULK OF COLDER AIR STAYS
LOCKED UP OVER WESTERN AND EASTERN CANADA CLOSER TO MORE PERSISTENT
TROUGHING. TEMPS INLAND FROM LK SUPERIOR AND NEAR LK MICHIGAN MOST
DAYS WILL BE AT OR ABOVE NORMAL. TEMPS ALONG LK SUPERIOR WILL BE AT
OR SLIGHTLY BLO NORMAL MOST OF THE TIME SINCE PREVAILING WINDS WILL
BE ONSHORE. WARMEST DAYS WILL BE TUESDAY AND AGAIN ON SATURDAY WITH
MOST AREAS WELL INTO THE 70S. COOLEST DAY THIS WEEK FOR ALL AREAS
SHOULD BE ON THURSDAY WHEN TEMPS ALONG LK SUPERIOR WILL LIKELY STAY
IN THE 50S.
WEAK SHORTWAVE TROUGH AND POCKET OF H85-H7 MOISTURE SWINGS ACROSS
WESTERN AND CENTRAL CWA ON TUESDAY MORNING THEN OVR EASTERN CWA
DURING AFTN HOURS. THOUGH SHARPEST LIFT IN FORM OF H85-H7 Q-VECTOR
CONVERGENCE IMPACTS LK SUPERIOR AND ISLE ROYALE/KEWEENAW PENINSULA
THROUGH MIDDAY...RIBBON OF LIFT CROSSES REST OF CWA AS WELL. WEAK
FORCING AND SUBTLE MOISTENING POINTS TO LOW CHANCE POPS. BUT...KIND
OF SIMILAR TO TODAY...COULD SEE ISOLD DAYTIME SHRA AND EVEN TSRA AS
SFC CAPES POP UP TO 300-500J/KG OVR SCNTRL IN THE AFTN. H7-H5 WINDS
45-55KT RESULTING IN DEEP LAYER SHEAR OVR 30 KTS. DO NOT EXPECT THERE
TO BE ENOUGH INSTABILITY TO TAKE ADVANTAGE OF THE STRONGER SHEAR
THOUGH SO DO NOT EXPECT ANY STRONG STORMS. DEEP DRYING IN H7 LAYER
QUICKLY ENDS ANY SHRA/TSRA BY LATE TUE AFTN. H7 DRYING AND NEUTRAL
HEIGHTS SHOULD KEEP CONDITIONS DRY THROUGH REST OF TUESDAY NIGHT.
ON WEDNESDAY...SHORTWAVE TROUGH SLIDES FROM ROCKIES TOWARD UPPER
MISSISSIPPI RIVER VALLEY. SFC LOW/WARM FRONT SET UP FROM NEB INTO
NORTHERN IL WHILE H85 WARM FRONT IS NOT MUCH FARTHER THAN THAT.
EDGE OF H7 MOISTURE MIGHT MAKE IT INTO NORTHERN WI...BUT SINCE 1-6KM
MUCAPE IS BARELY INTO SOUTHERN MN AND CNTRL WI...HAVE HARD TIME
THINKING THAT THE INCREASE IN H7 MOSITURE WOULD RESULT IN NOTHING
MORE THAN A FEW SPRINKLES OUT OF A SCT-BKN MID CLOUD DECK. NOT
WORTH PUTTING ANY POPS INTO SOUTHERN CWA. OTHER THING TO WATCH ON
WEDNESDAY IS SHORTWAVE TIED INTO NORTHERN STREAM TROUGH PUSHING INTO
ONTARIO. TREND IS FOR WAVE TO BE STRONGER...BUT MAJORITY OF MODELS
KEEP WAVE ON WNW-ESE TRACK OVER NORTHERN LK SUPERIOR IN THE MORNING
AND OVER ONTARIO EAST OF SAULT STE MARIE BY AFTN. SFC BASED
INSTABILITY AND STEEPER H7-H5 LAPSE RATES SHOULD SPUR ON SCATTERED
SHRA/TSRA NORTH AND EAST OF LK SUPERIOR WITH DAYTIME HEATING. ONLY
THE GEM-NH SHOWS THE WAVE DIGGING ENOUGH SOUTH TO HAVE ANY QPF OVR
UPR MICHIGAN THOUGH AND THAT IS ONLY OVR FAR EAST CWA. MAJORITY
RULES FOR NOW SO HAVE NOT PUT ANY POPS IN OVER THE EAST. MAX TEMPS
MAY SHOW VARIATION CLOSER TO LK SUPERIOR AS LAKE COOLING IS ENHANCED
BY AFTN WITH DEVELOPING NORTH GRADIENT FLOW. MAY SEE TEMPS QUICKLY
RISE WEDNESDAY MORNING CLOSER TO LK SUPERIOR THEN FALL OFF IN THE
AFTN. FARTHER INLAND...EXPECT ANOTHER DAY WITH HIGHS INTO THE 70S.
SHORTWAVE PASSAGE RESULTS IN H85-H7 WINDS VEERING MORE NORTH LATER
WEDNESDAY NIGHT INTO THURSDAY. H85 THERMAL TROUGH ALSO PRESENT. NOT
EXPECTING ANY SHRA AS FORCING IS MINIMAL...BUT MAY SEE DECENT CLOUD
COVER IN THE MORNING. BY AFTN...H85 RH PROGS SHOWING LAKE
STABILIZING SIGNAL WITH MINIMUM RH SHOWING UP OVR LK SUPERIOR AFT
18Z. PROBABLY WILL SEE CLEARING DEVELOP CLOSER TO LK SUPERIOR AND
OVER EAST DUE TO STABILIZING FLOW. EVEN WITH CLEARING WILL BE COOL
DAY ALONG LK SUPERIOR AS MOST LOCATIONS STAY IN THE 50S WITH STIFF
NORTHERLY WINDS. INLAND TEMPS WILL BE IN THE UPR 60S TO PERHAPS
LOWER 70S. HIGH PRESSURE BUILDS ACROSS THURSDAY NIGHT THROUGH
FRIDAY AND NOW EVEN THROUGH MOST OF FRIDAY NIGHT. MOSTLY CLEAR SKIES
WILL PREVAIL AND GIVEN TREND OF HIGH STAYING AROUND LONGER...FRIDAY
NIGHT NOW LOOKING GENERALLY FREE OF ANY SHRA/TSRA EXCEPT FAR WEST
CWA.
WEEKEND FORECAST MUDDLED AS MID CONUS RIDGE FLATTENS OUT FROM
NORTHERN PLAINS TO UPPER GREAT LAKES. STRONGER SHORTWAVE TROUGHS
CUTTING THROUGH THE RIDGE FORECAST TO BE OVR CNTRL CANADA AND OVR
THE MIDDLE MISSISSIPPI RIVER VALLEY. TALKING DAY 6 AND 7 SO HARD TO
GET TOO HUNG UP ON THESE TYPE OF DETAILS YET. OVERALL THEME THOUGH
IS SLOWER ARRIVAL OF SHRA/TSRA CHANCES AND/OR A GENERAL LACKING
FOCUS FOR SHRA/TSRA. CONSENSUS POPS IN THE LOW CHANCE RANGE USED BUT
DID PULL POPS OVER EASTERN CWA ON SATURDAY AS THAT AREA IS IN CLOSER
PROXIMITY OF STUBBORN SFC RIDGING. TEMPS FOR NEXT WEEKEND SHOULD BE
SIMILAR TO READINGS THIS WEEK WITH HIGHS MAINLY IN THE 70S AND
POSSIBLY WARMER IF THERE ARE LESS CLOUDS/SHRA/TSRA.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 725 AM EDT MON JUN 10 2013
WITH SOME MORNING SUNSHINE/VFR CONDITIONS...EXPECT SOME SHRA TO
DEVELOP WITH THE DAYTIME HEATING AND IMPACT MAINLY IWD AND SAW
BEFORE THE SHRA DISSIPATE BY 00Z WITH WANING DAYLIGHT. A WEAK HI
PRES WILL MOVE IN THIS EVNG...AND WITH LGT WINDS AND JUST SOME
PATCHY HI CLDS...SETUP LOOKS GOOD FOR SOME FOG TO FORM. IFR
CONDITIONS APPEAR LIKELY OVERNGT.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 412 AM EDT MON JUN 10 2013
AS LO PRES IN THE LOWER GREAT LAKES SHIFTS SLOWLY TO THE E TODAY...
EXPECT E-SE WINDS UP TO 20 KTS TO SLOWLY DIMINISH W-E WITH THE
WEAKENING PRES GRADIENT AND UNDER 15 KTS TONIGHT. DID MAINTAIN
PATCHY FOG OVER MUCH OF THE WESTERN LAKE WHERE SOME SHOWERS HAVE
FURTHER MOISTENED THE LOW LEVELS. THE WEAK PRES GRADIENT WILL
PREVAIL THRU FRI...SO PLAN ON WINDS UNDER 15 KTS TUE THRU FRI.
COULD BE A BRIEF PERIOD OF STRONGER WINDS...UP TO 20 KTS IN
GUSTS...LATE WEDNESDAY NIGHT AND THURSDAY MORNING. RELATIVELY
MOIST AIR OVER THE STILL CHILLY LAKE WATERS WILL RESULT IN
LINGERING FOG PATCHES UNTIL DRIER AIR ARRIVES ON FRI.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...JLA
AVIATION...KC
MARINE...KC/JLA
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
416 AM EDT MON JUN 10 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 412 AM EDT MON JUN 10 2013
00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW AN UPR RDG
EXTENDING FM NW ONTARIO THRU THE GREAT LKS TO THE MID ATLANTIC
COAST. THERE ARE 2 CLOSED LOWS UPSTREAM...ONE MOVING THRU THE MID MS
RIVER VALLEY AND ANOTHER OVER SASKATCHEWAN TO THE N OF MEAN RDG OVER
THE WRN CONUS. A SHRTWV IS MOVING INTO NE MN BTWN THE 2 CLOSED LOWS
AND GENERATING AN AREA RA OVER FAR NW LK SUP AND NE MN AS THE DPVA/
DEEP LYR QVECTOR CNVGC AHEAD OF THIS FEATURE INTERACTS WITH DEEP
MSTR SHOWN ON THE 00Z INL RAOB. BUT SINCE THE DEEPER MSTR AND
FORCING ASSOCIATED WITH THE CLOSED LO IN THE MID MS RIVER VALLEY ARE
TO THE S OF UPR MI...THERE IS NO DYNAMIC SUPPORT FOR PCPN OVER UPR
MI...WITH AN ABSENCE OF SGNFT RADAR RETURNS OVER THE AREA DESPITE
MOCLDY SKIES. THE CLDS HAVE LIMITED THE DIURNAL FALL OF TEMP...WITH
MOST PLACES REPORTING TEMPS IN THE 50S TO LO 60S EARLY THIS MRNG.
SOME BREAKS IN THE CLDS ARE MOVING NE INTO UPR MI FM WI. THICKER
CLDS/SOME ISOLD -SHRA ARE MOVING N THRU LWR MI.
MAIN FCST CONCERNS IN THE SHORT TERM INVOLVE PCPN CHCS ASSOCIATED
WITH SHRTWV NOW MOVING THRU NE MN.
TDAY...SHRTWV IN NE MN IS PROGGED TO LIFT NEWD INTO NW ONTARIO ON
THE SE FLANK OF NEARLY STNRY CLOSED LO OVER SASKATCHEWAN. DPVA/H85-5
QVECTOR CNVGC ASSOCIATED WITH THIS FEATURE ARE PROGGED TO BRUSH THE
NW CWA INTO THIS AFTN BEFORE THE SHRTWV LIFTS FARTHER TO THE NE AND
GIVES WAY TO DNVA/DEEP LYR QVECTOR DVGC/MID LVL DRYING. MODELS SHOW
BULK OF PCPN ACCOMPANYING THIS SHRTWV PASSAGE REMAINING TO THE NW OF
EVEN THE KEWEENAW. SO OPTED TO CUT POPS TO NO HIER THAN SCHC THIS
MRNG OVER THE LAND CWA. DID ADD SCHC POPS OVER THE E TO ACCOUNT FOR
ISOLD -SHRA MOVING N THRU NRN LWR MI. EVEN AFT THE DYNAMIC SUPPORT
SWINGS TO THE N THIS AFTN...BULK OF RECENT NUMERICAL GUIDANCE IS
GENERATING QPF OVER MAINLY THE INTERIOR W HALF OF THE CWA AS DAYTIME
HEATING DESTABILIZES THE ATMOSPHERE AND LK BREEZE BNDRYS PROVIDE
SOME LLVL FOCUS. TENDED TO RAISE FCST MAX TEMPS A FEW DEGREES TO
ACCOUNT FOR SOME BREAKS IN THE CLDS MOVING NE FM WI AND ABSENCE OF
DYNAMIC FORCING OVER MOST OF THE FA. THE ONLY EXCEPTION WAS THE E...
WHERE MORE CLDS STREAMING NWD THRU LWR MI MIGHT HOLD DOWN THE
DIURNAL TEMP INCRS. EVEN THOUGH WARMING/DRYING ABV H6 WITH THE
ARRIVAL OF THE NEGATIVE DYNAMICS SETS IN AFT 18Z AND WL LIMIT
POTENTIAL FOR DEEP CNVCTN...MODIFIED NAM FCST SDNG FOR THE INTERIOR
W FOR SFC T/TD OF 75/57 YIELDS SBCAPE NEAR 450 J/KG AND KINX OF 33.
GOING CHC POPS/SCHC OF TS LOOKS TO BE IN PRETTY GOOD ORDER.
TNGT...IN THE ABSENCE OF ANY DYNAMIC SUPPORT...EXPECT DIURNAL SHRA
OVER MAINLY THE W HALF TO DIMINISH THIS EVNG WITH LOSS OF DAYTIME
HEATING. ALTHOUGH ANOTHER SHRTWV IS PROGGED TO RACE EWD ALONG THE
CNDN BORDER THRU TNGT IN THE FAST WLY FLOW ON THE SRN FLANK OF THE
SASKATCHEWAN CLOSED LO AND APRCH THE NW CWA LATER WITH SOME
DPVA/DEEP LYR QVECTOR CNVGC...FAIRLY DRY MID LVLS/LLVL ACYC FLOW/
ABSENCE OF ANY DIURNAL HEATING WL LIMIT ACCOMPANYING POPS...
ESPECIALLY SINCE THE FOCUS OF THE ASSOCIATED FORCING IS FCST TO PASS
TO THE N. DID RETAIN SOME CHC POPS OVER THE NW CWA TO ACCOUNT FOR
THIS DISTURBANCE. OTRW...EXPECT SOME FOG TO FORM OVER THE INTERIOR
WITH THE MID LVL DRYING/LGT WINDS...ESPECIALLY IN AREAS WHERE SOME
RA MIGHT FALL THIS AFTN AND FURTHER MOISTEN THE LLVLS.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 412 AM EDT MON JUN 10 2013
LARGER SCALE PATTERN BY TUESDAY INDICATES STRING OF TROUGHS ACROSS
CANADA AND TROUGHING OVER NORTHWEST CONUS AND NORTHEAST CONUS.
SHALLOW RIDGING IS ANCHORED OVER SOUTH CENTRAL CONUS. THROUGH REST
OF THE WEEK TROUGHING OVER CANADA SPLITS WITH RIDGING ATTEMPTING TO
BUILD INTO CANADIAN PRAIRIES. EVENTUALLY THIS RIDGE MOVES EAST INTO
NORTHERN PLAINS AND UPPER GREAT LAKES BY START OF NEXT WEEKEND. YET
ANOTHER TROUGH WILL THEN SWING BACK ACROSS UPPER LAKES TO CLOSE THE
WEEKEND. OVERALL PATTERN WILL NOT BRING MUCH RAIN TO UPPER LAKES BUT
IT ALSO SHOULD NOT BE THAT COLD EITHER AS BULK OF COLDER AIR STAYS
LOCKED UP OVER WESTERN AND EASTERN CANADA CLOSER TO MORE PERSISTENT
TROUGHING. TEMPS INLAND FROM LK SUPERIOR AND NEAR LK MICHIGAN MOST
DAYS WILL BE AT OR ABOVE NORMAL. TEMPS ALONG LK SUPERIOR WILL BE AT
OR SLIGHTLY BLO NORMAL MOST OF THE TIME SINCE PREVAILING WINDS WILL
BE ONSHORE. WARMEST DAYS WILL BE TUESDAY AND AGAIN ON SATURDAY WITH
MOST AREAS WELL INTO THE 70S. COOLEST DAY THIS WEEK FOR ALL AREAS
SHOULD BE ON THURSDAY WHEN TEMPS ALONG LK SUPERIOR WILL LIKELY STAY
IN THE 50S.
WEAK SHORTWAVE TROUGH AND POCKET OF H85-H7 MOISTURE SWINGS ACROSS
WESTERN AND CENTRAL CWA ON TUESDAY MORNING THEN OVR EASTERN CWA
DURING AFTN HOURS. THOUGH SHARPEST LIFT IN FORM OF H85-H7 Q-VECTOR
CONVERGENCE IMPACTS LK SUPERIOR AND ISLE ROYALE/KEWEENAW PENINSULA
THROUGH MIDDAY...RIBBON OF LIFT CROSSES REST OF CWA AS WELL. WEAK
FORCING AND SUBTLE MOISTENING POINTS TO LOW CHANCE POPS. BUT...KIND
OF SIMILAR TO TODAY...COULD SEE ISOLD DAYTIME SHRA AND EVEN TSRA AS
SFC CAPES POP UP TO 300-500J/KG OVR SCNTRL IN THE AFTN. H7-H5 WINDS
45-55KT RESULTING IN DEEP LAYER SHEAR OVR 30 KTS. DO NOT EXPECT THERE
TO BE ENOUGH INSTABILITY TO TAKE ADVANTAGE OF THE STRONGER SHEAR
THOUGH SO DO NOT EXPECT ANY STRONG STORMS. DEEP DRYING IN H7 LAYER
QUICKLY ENDS ANY SHRA/TSRA BY LATE TUE AFTN. H7 DRYING AND NEUTRAL
HEIGHTS SHOULD KEEP CONDITIONS DRY THROUGH REST OF TUESDAY NIGHT.
ON WEDNESDAY...SHORTWAVE TROUGH SLIDES FROM ROCKIES TOWARD UPPER
MISSISSIPPI RIVER VALLEY. SFC LOW/WARM FRONT SET UP FROM NEB INTO
NORTHERN IL WHILE H85 WARM FRONT IS NOT MUCH FARTHER THAN THAT.
EDGE OF H7 MOISTURE MIGHT MAKE IT INTO NORTHERN WI...BUT SINCE 1-6KM
MUCAPE IS BARELY INTO SOUTHERN MN AND CNTRL WI...HAVE HARD TIME
THINKING THAT THE INCREASE IN H7 MOSITURE WOULD RESULT IN NOTHING
MORE THAN A FEW SPRINKLES OUT OF A SCT-BKN MID CLOUD DECK. NOT
WORTH PUTTING ANY POPS INTO SOUTHERN CWA. OTHER THING TO WATCH ON
WEDNESDAY IS SHORTWAVE TIED INTO NORTHERN STREAM TROUGH PUSHING INTO
ONTARIO. TREND IS FOR WAVE TO BE STRONGER...BUT MAJORITY OF MODELS
KEEP WAVE ON WNW-ESE TRACK OVER NORTHERN LK SUPERIOR IN THE MORNING
AND OVER ONTARIO EAST OF SAULT STE MARIE BY AFTN. SFC BASED
INSTABILITY AND STEEPER H7-H5 LAPSE RATES SHOULD SPUR ON SCATTERED
SHRA/TSRA NORTH AND EAST OF LK SUPERIOR WITH DAYTIME HEATING. ONLY
THE GEM-NH SHOWS THE WAVE DIGGING ENOUGH SOUTH TO HAVE ANY QPF OVR
UPR MICHIGAN THOUGH AND THAT IS ONLY OVR FAR EAST CWA. MAJORITY
RULES FOR NOW SO HAVE NOT PUT ANY POPS IN OVER THE EAST. MAX TEMPS
MAY SHOW VARIATION CLOSER TO LK SUPERIOR AS LAKE COOLING IS ENHANCED
BY AFTN WITH DEVELOPING NORTH GRADIENT FLOW. MAY SEE TEMPS QUICKLY
RISE WEDNESDAY MORNING CLOSER TO LK SUPERIOR THEN FALL OFF IN THE
AFTN. FARTHER INLAND...EXPECT ANOTHER DAY WITH HIGHS INTO THE 70S.
SHORTWAVE PASSAGE RESULTS IN H85-H7 WINDS VEERING MORE NORTH LATER
WEDNESDAY NIGHT INTO THURSDAY. H85 THERMAL TROUGH ALSO PRESENT. NOT
EXPECTING ANY SHRA AS FORCING IS MINIMAL...BUT MAY SEE DECENT CLOUD
COVER IN THE MORNING. BY AFTN...H85 RH PROGS SHOWING LAKE
STABILIZING SIGNAL WITH MINIMUM RH SHOWING UP OVR LK SUPERIOR AFT
18Z. PROBABLY WILL SEE CLEARING DEVELOP CLOSER TO LK SUPERIOR AND
OVER EAST DUE TO STABILIZING FLOW. EVEN WITH CLEARING WILL BE COOL
DAY ALONG LK SUPERIOR AS MOST LOCATIONS STAY IN THE 50S WITH STIFF
NORTHERLY WINDS. INLAND TEMPS WILL BE IN THE UPR 60S TO PERHAPS
LOWER 70S. HIGH PRESSURE BUILDS ACROSS THURSDAY NIGHT THROUGH
FRIDAY AND NOW EVEN THROUGH MOST OF FRIDAY NIGHT. MOSTLY CLEAR SKIES
WILL PREVAIL AND GIVEN TREND OF HIGH STAYING AROUND LONGER...FRIDAY
NIGHT NOW LOOKING GENERALLY FREE OF ANY SHRA/TSRA EXCEPT FAR WEST
CWA.
WEEKEND FORECAST MUDDLED AS MID CONUS RIDGE FLATTENS OUT FROM
NORTHERN PLAINS TO UPPER GREAT LAKES. STRONGER SHORTWAVE TROUGHS
CUTTING THROUGH THE RIDGE FORECAST TO BE OVR CNTRL CANADA AND OVR
THE MIDDLE MISSISSIPPI RIVER VALLEY. TALKING DAY 6 AND 7 SO HARD TO
GET TOO HUNG UP ON THESE TYPE OF DETAILS YET. OVERALL THEME THOUGH
IS SLOWER ARRIVAL OF SHRA/TSRA CHANCES AND/OR A GENERAL LACKING
FOCUS FOR SHRA/TSRA. CONSENSUS POPS IN THE LOW CHANCE RANGE USED BUT
DID PULL POPS OVER EASTERN CWA ON SATURDAY AS THAT AREA IS IN CLOSER
PROXIMITY OF STUBBORN SFC RIDGING. TEMPS FOR NEXT WEEKEND SHOULD BE
SIMILAR TO READINGS THIS WEEK WITH HIGHS MAINLY IN THE 70S AND
POSSIBLY WARMER IF THERE ARE LESS CLOUDS/SHRA/TSRA.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 126 AM EDT MON JUN 10 2013
E TO SE PREVAILING FLOW SHOULD HELP MAINTAIN SOMEWHAT DRIER AIR AT
THE LOW-LEVELS...KEEPING CONDITIONS VFR THROUGH MOST OF THE PD
DESPITE PCPN. WITH RAINFALL WETTING THE GROUND MORE SO AT
KIWD...THERE IS THE POTENTIAL FOR LOWER CLOUDS/FOG TO FORM
OVERNIGHT. HOWEVER...SINCE LOW-LEVEL WINDS REMAIN FROM A DOWNSLOPING
SE DIRECTION...POTENTIAL APPEARS MINIMAL. EARLY MON AFTN...DAYTIME
HEATING MAY BEGIN TO POP A FEW SHRA...ESPECIALLY AROUND KIWD. BY
LATE MON EVENING...THERE COULD BE A POTENTIAL FOR PATCHY
FOG...ESPECIALLY AT KCMX WHERE HIGHER DEWPOINTS ALONG LAKE SUPERIOR
MAY BE MORE CONDUCIVE FOR FOG FORMATION
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 412 AM EDT MON JUN 10 2013
AS LO PRES IN THE LOWER GREAT LAKES SHIFTS SLOWLY TO THE E TODAY...
EXPECT E-SE WINDS UP TO 20 KTS TO SLOWLY DIMINISH W-E WITH THE
WEAKENING PRES GRADIENT AND UNDER 15 KTS TONIGHT. DID MAINTAIN
PATCHY FOG OVER MUCH OF THE WESTERN LAKE WHERE SOME SHOWERS HAVE
FURTHER MOISTENED THE LOW LEVELS. THE WEAK PRES GRADIENT WILL
PREVAIL THRU FRI...SO PLAN ON WINDS UNDER 15 KTS TUE THRU FRI.
COULD BE A BRIEF PERIOD OF STRONGER WINDS...UP TO 20 KTS IN
GUSTS...LATE WEDNESDAY NIGHT AND THURSDAY MORNING. RELATIVELY
MOIST AIR OVER THE STILL CHILLY LAKE WATERS WILL RESULT IN
LINGERING FOG PATCHES UNTIL DRIER AIR ARRIVES ON FRI. &&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...JLA
AVIATION...VOSS
MARINE...KC/JLA
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
128 AM EDT MON JUN 10 2013
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 412 PM EDT SUN JUN 9 2013
WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW A SHORTWAVE OVER NW IA
DOWNSTREAM OF A RIDGE OVER THE WRN CONUS. ANOTHER SHORTWAVE IS
MOVING ACROSS ND AND ADJACENT SASKATCHEWAN/MANITOBA IN ASSOCIATION
WITH A BROAD CLOSED MID LEVEL LOW OVER SW CANADA. SHORTWAVE OVER IA
HAS MANAGED TO SWING A BAND OF SHRA N INTO WRN UPPER MI TODAY. SHRA
HAVE BEEN SUPPORTED BY LOW/MID LEVEL FRONTOGENESIS AND PROBABLY SOME
RIGHT ENTRANCE UPPER DIVERGENCE FROM JET STREAK EXTENDING FROM LAKE
SUPERIOR TO NEW ENGLAND. ERN EDGE OF SHRA AREA HAS BATTLED
ANTECEDENT DRY AIR MASS AT THE LOW/MID LEVELS PER 12Z KGRB/KAPX
SOUNDINGS. IT APPEARS SPRINKLES HAVE REACHED AS FAR E AS MEMONINEE
AND DICKINSON COUNTIES TODAY.
WITH RECENT RADAR IMAGERY SHOWING ERN EDGE OF PCPN BAND FALLING
APART AS IT MOVES FARTHER INTO DRIER AIR MASS...WILL SHOW A
DIMINISHING POP TREND OVER THE W DURING THE NEXT SEVERAL HRS.
SPRINKLES MAY GET AS FAR E AS WRN MARQUETTE COUNTY. OTHERWISE...WITH
SHORTWAVE OVER IA DRIFTING ESE INTO IL TONIGHT...THIS DISTURBANCE IS
NOT LIKELY TO PROVIDE ANY FORCING FOR PCPN OVER UPPER MI. IN
FACT...PER QVECTORS...MODELS INDICATE A FAIRLY PRONOUNCED SPLIT IN
DEEP LAYER FORCING DEVELOPING OVER UPPER MI BTWN THE WAVE MOVING
INTO IL AND THE AFOREMENTIONED SHORTWAVE CURRENTLY OVER ND THAT WILL
BE MOVING INTO FAR NE MN/NRN ONTARIO TONIGHT. THIS WILL LEAVE MUCH
OF THE FCST AREA IN AN AREA OF LITTLE/NO DYNAMIC FORCING TONIGHT.
SO...FCST TONIGHT WILL RETAIN THE IDEA OF HIGHER POPS OVER THE NW...
ESPECIALLY TOWARD ISLE ROYALE...AND LOW CHC/SCHC POPS ELSEWHERE...
EXCEPT FOR THE E WHICH SHOULD REMAIN DRY TONIGHT UNDER LINGERING
MID/UPPER RIDGING. A NUMBER OF THE HIGHER RES MODELS SHOW REMNANTS
OF CONVECTION DEVELOPING IN WRN LWR MI ROTATING NW INTO SCNTRL UPPER
MI THIS EVENING. WILL BE INTERESTING TO SEE IF THAT DOES HAPPEN.
SHORTWAVE THAT REACHES NE MN/ADJACENT NRN ONTARIO LATE TONIGHT WILL
CONTINUE EASTWARD MON. WAVE WILL SUPPORT BETTER PCPN CHANCES ACROSS
WRN AND NRN LAKE SUPERIOR INTO PORTIONS OF NW UPPER MI MON MORNING.
MUCH OF THE FORCING WITH WAVE WILL THEN SHIFT N AND E OF THE AREA AS
THE AFTN WEARS ON. ATTENTION THEN TURNS TO POTENTIAL FOR AFTN
CONVECTION. NAM SHOWS MLCAPE INCREASING TO 150-500J/KG IN THE AFTN
WITH THE GREATEST INSTABILITY OVER THE INTERIOR W HALF OF THE FCST
AREA. THE GFS HAS SIMILAR VALUES...BUT ITS INSTABILITY IS CONFINED
TO JUST THE W HALF OF UPPER MI. WITH THE POSSIBILITY OF THE TAIL END
OF DEPARTING DEEP LAYER FORCING STILL SKIRTING THE AREA IN THE
AFTN...AVBL INSTABILITY IS CERTAINLY SUFFICIENT FOR A MENTION OF
SHRA OVER MUCH OF THE AREA IN THE AFTN (CHC POPS OVER THE INTERIOR W
HALF AND SCHC E). CONVECTION OVER THE W SHOULD BE FURTHER AIDED BY
LAKE BREEZE CONVERGENCE. OPTED TO INCLUDE SCHC THUNDER MENTION OVER
THE INTERIOR W HALF WHERE INSTABILITY WILL BE MAXIMIZED.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 412 PM EDT SUN JUN 9 2013
DIURNALLY DRIVEN RAIN SHOWERS AND THUNDERSTORMS ACROSS THE INTERIOR
WEST AND CENTRAL AREAS WILL DIMINISH MONDAY NIGHT AS WE LOSE HEATING
OVERNIGHT. MEANWHILE...LOW PRESSURE WILL MOVE FROM SASKATCHEWAN INTO
ONTARIO BY TUESDAY EVENING. THIS WILL BRING A SHORTWAVE ACROSS UPPER
MICHIGAN TUESDAY. ADDITIONALLY...LOW PRESSURE WILL MOVE FROM THE
OHIO VALLEY TOWARDS THE NEW ENGLAND STATES. HIGH PRESSURE CENTERED
OVER TEXAS WILL KEEP A RIDGE ACROSS MUCH OF THE CENTRAL U.S. FOR
THIS TIME PERIOD.
AS IT IS...UPPER MICHIGAN WILL BE UNDER THE INFLUENCE OF WEAK
RIDGING AND A PASSING SUBTLE SHORTWAVE TUESDAY. THOUGH THERE WILL BE
MOISTURE LINGERING AROUND/PWATS UP TO 115 PERCENT OF
NORMAL...PRECIPITATION WILL BE LIMITED BY THIS RIDGE OVER LAND. HAVE
SLIGHT CHANCE POPS MOVING WEST TO EAST ACROSS THE CWA THROUGH THE
DAY ON TUESDAY. THE BEST FORCING WITH THIS SHORTWAVE IS PRIMARILY
NORTH OF LAKE SUPERIOR...SO CHANCE POPS ARE ACROSS THE WESTERN AND
NORTHERN PORTIONS OF THE LAKE WITH THE SHORTWAVE. ADDITIONAL SHOWERS
COULD POP UP ALONG THE LAKE BREEZE BOUNDARIES TOWARDS THE
AFTERNOON...SO KEPT SLIGHT CHANCE POPS IN THIS AREA UNTIL 00Z.
AS FOR WEDNESDAY...WITH HIGH PRESSURE SETTING UP ACROSS THE CENTRAL
U.S. EXPECT MCS DEVELOPMENT TO OCCUR ALONG THE RIDGE BOUNDARY AS
SEVERAL SHORTWAVES SLIDE THROUGH. THIS WILL REMAIN SOUTH OF UPPER
MICHIGAN HOWEVER...LIKELY OVER CENTRAL/LOWER WI. THE UPPER LOW THAT
BROUGHT THE SHORTWAVE THROUGH UPPER MI ON TUESDAY WILL CONTINUE TO
GENERATE PRECIPITATION...OVER PRIMARILY ONTARIO AND QUEBEC. WITH
RIDGE EXPANDING NORTHWARD DO NOT EXPECT ANYTHING MORE THAN SOME
SCATTERED CLOUD COVER OVER UPPER MI.
THE RIDGE OF HIGH PRESSURE WILL BUILD INTO THE GREAT LAKES REGION
FOR THURSDAY AND MUCH OF FRIDAY...WHICH WILL KEEP THE WEATHER QUIET.
WITH COOL NORTHERLY WINDS OFF THE LAKE ON THURSDAY AND MIXING TO
AROUND 950MB IN MOST LOCATIONS EXPECT HIGH TEMPERATURES TO RANGE
FROM THE MID 60S TO LOW 70S...WITH THE WARMER TEMPERATURES INLAND
FROM LAKE SUPERIOR. REGIONS CLOSEST TO THE LAKES COULD SEE SLIGHTLY
LOWER TEMPERATURES.
ON FRIDAY AFTERNOON CLOUD COVER IN THE WEST INCREASES WITH AN
APPROACHING AREA OF LOW PRESSURE. STILL EXPECT MOST AREAS TO
EXPERIENCE FULL DAYTIME HEATING THOUGH...AND WITH BETTER MIXING TO
THE 850MB LEVEL/TEMPS AROUND 12-14C AND DEVELOPING SOUTHERLY WINDS
EXPECT HIGHS TO REACH INTO THE MID 70S AWAY FROM LAKE SUPERIOR.
FRIDAY NIGHT-SUNDAY LOW PRESSURE OVER MANITOBA WILL CROSS EASTWARD
INTO QUEBEC...JUST NORTH OF LAKE SUPERIOR. CORRESPONDING COLD FRONT
WILL CROSS UPPER MICHIGAN SATURDAY AFTERNOON INTO SUNDAY EVENING.
WITH SOUTHERLY WINDS BRINGING MORE MOISTURE TO THE AREA/DEWPOINTS
NEARING 60F/ AND PASSAGE OF THE COLD FRONT...EXPECT SHOWERS AND A
FEW THUNDERSTORMS TO SPREAD EASTWARD ACROSS THE CWA.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 126 AM EDT MON JUN 10 2013
E TO SE PREVAILING FLOW SHOULD HELP MAINTAIN SOMEWHAT DRIER AIR AT
THE LOW-LEVELS...KEEPING CONDITIONS VFR THROUGH MOST OF THE PD
DESPITE PCPN. WITH RAINFALL WETTING THE GROUND MORE SO AT
KIWD...THERE IS THE POTENTIAL FOR LOWER CLOUDS/FOG TO FORM
OVERNIGHT. HOWEVER...SINCE LOW-LEVEL WINDS REMAIN FROM A DOWNSLOPING
SE DIRECTION...POTENTIAL APPEARS MINIMAL. EARLY MON AFTN...DAYTIME
HEATING MAY BEGIN TO POP A FEW SHRA...ESPECIALLY AROUND KIWD. BY
LATE MON EVENING...THERE COULD BE A POTENTIAL FOR PATCHY
FOG...ESPECIALLY AT KCMX WHERE HIGHER DEWPOINTS ALONG LAKE SUPERIOR
MAY BE MORE CONDUCIVE FOR FOG FORMATION
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 412 PM EDT SUN JUN 9 2013
AS LOW PRES OVER NW IA DRIFTS E...EXPECT EASTERLY WINDS UP TO AROUND
20KT ACROSS LAKE SUPERIOR THRU MON. LOCALLY HIGHER WINDS TO AROUND
25KT SHOULD OCCUR OVER THE FAR W THRU THIS EVENING DUE TO COASTAL
CONVERGENCE. WITH SOME RAIN FALLING OVER THE WRN PART OF THE LAKE...
PATCHY FOG MAY DEVELOP TONIGHT OVER THE W. WEAK HIGH PRES WILL
RETURN AND BRING GENERALLY LIGHT WINDS FOR TUE THRU FRI. MUCH OF
THAT PERIOD WILL SEE WINDS AOB 15KT.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...ROLFSON
LONG TERM...MCD
AVIATION...VOSS
MARINE...ROLFSON
AREA FORECAST DISCUSSION
NWS DULUTH MN
1224 AM CDT MON JUN 10 2013
.AVIATION...06Z TAF ISSUANCE...
RAIN AND DRIZZLE SHOULD TAPER OFF BEFORE 08Z ACROSS ALL AREA
TERMINALS WITH FOG AND LOW MVFR/IFR CIGS DEVELOPING DURING THE OVER
NIGHT AND EARLY MONDAY MORNING HOURS. CIGS WILL GRADUALLY LIFT
THROUGH THE LATE MORNING AND EVENTUALLY BECOME VFR BY THE EARLY
AFTERNOON ACROSS THE ENTIRE REGION. WINDS WILL BE LIGHT AND VARIABLE
THROUGH THE DAY. THE NEXT WEAK FRONT MOVES IN FROM THE NW LATE MON
EVENING AND BRING VCSH TO HIB AND INL...WITH ADDITIONAL SLIGHT
CHANCES FOR RAIN AFTER 06Z TO THE REMAINING TERMINALS.
&&
.PREV DISCUSSION... /ISSUED 620 PM CDT SUN JUN 9 2013/
AVIATION...00Z TAF ISSUANCE...
RAIN SHOWERS AND/OR -DZ WILL CONTINUE THROUGH THIS EVENING WITH
CONDITIONS DRYING OUT AT BRD FIRST...THEN HIB...DLH...HYR AND INL.
WILL LIKELY SEE IFR FOG DEVELOP TONIGHT...WITH LOCALIZED AREAS OF
LIFR VSBYS LATE TONIGHT/EARLY MON MORNING. CIGS WILL GRADUALLY
LIFT THROUGH THE MORNING HOURS...WITH HIGH-END MVFR CIGS BY THE
EARLY AFTERNOON...AND VFR BY THE MID TO LATE AFTERNOON.
PREV DISCUSSION... /ISSUED 307 PM CDT SUN JUN 9 2013/
SHORT TERM.../NOW - MONDAY/
THE FOCUS IS ON THE WIDESPREAD RAIN COVERING MUCH OF THE FORECAST
AREA THIS AFTERNOON...AND HOW THAT WILL CONTINUE AND LINGER
THROUGH TONIGHT. THE MODELS ARE IN FAIRLY GOOD AGREEMENT...BUT I
HAVE AND CONTINUE TO LEAN ON THE HRRR SIMULATED REFLECTIVITY AS
FAR TIMING OF THE PCPN THROUGH THIS EVENING GOES SINCE THE HRRR
SEEMS TO BE DOING PRETTY WELL.
AT 300PM/2000Z...HIGH PRESSURE STRETCHED FROM NEW YORK INTO THE
EASTERN GREAT LAKES AND ONTARIO. A LOW PRESSURE SYSTEM WAS
CENTERED NEAR NW IOWA...AND ANOTHER LOW PRESSURE SYSTEM IN CENTRAL
SASKATCHEWAN. A TROUGH BOUNDARY EXTENDED FROM THE SASKATCHEWAN
LOW THROUGH THE EASTERN DAKOTAS TO THE IOWA LOW. PLENTY OF
MOISTURE WAS SURGING NORTHWARD AHEAD OF THE IOWA LOW AND THE
TROUGH IN THE EASTERN DAKOTAS. THERE WAS WIDESPREAD LIGHT TO
MODERATE RAIN ACROSS THE NORTHLAND. THERE WERE EASTERLY WINDS OF 5
TO 15 MPH. TEMPERATURES RANGED FROM THE MID TO LOWER 60S ACROSS
THE SE AND FAR N FORECAST AREA...WHILE THE REST OF THE FORECAST
AREA HAD TEMPERATURES IN THE LOW TO UPPER 50S DUE TO THE RAIN AND
COOL WINDS OFF LAKE SUPERIOR.
THROUGH TONIGHT...THE LOW IN NW IOWA WILL MOVE EAST TO NEAR
SOUTHERN LAKE MICHIGAN BY LATE TONIGHT....WHILE THE TROUGH IN THE
EASTERN DAKOTAS WILL SHIFT EAST TO THE EASTERN FORECAST AREA. HIGH
PRESSURE WILL MOVE INTO THE PLAINS IN THE WAKE OF THE LOW AND
TROUGH. THE RAIN SHOWERS ACROSS THE NORTHLAND SHOULD GENERALLY
LIFT NORTH AND EASTWARD THIS AFTERNOON AND THEN GRADUALLY DIMINISH
FROM WEST TO EAST TONIGHT. THE WINDS WILL WEAKEN AND BECOME
NEGLIGIBLE LATER TONIGHT...MAKING FOG LIKELY FOR LATE TONIGHT AND
INTO TOMORROW MORNING. OVERNIGHT LOWS SHOULD BE IN THE UPPER 40S
TO MID 50S.
MONDAY...WEAK HIGH PRESSURE WILL MOVE INTO THE NORTHLAND. THIS
HELP KEEP MOST OF THE NORTHLAND DRY...BUT THERE COULD BE LINGERING
RAIN SHOWERS/STORMS ACROSS THE EASTERN FORECAST AREA...AS WELL AS
AFTERNOON SHOWERS/STORMS ACROSS THE NW FORECAST AREA THAT WOULD BE
RELATED TO LOW PRESSURE MOVING ACROSS SOUTHERN MANITOBA. I HAVE
SOME UNCERTAINTY ABOUT THE TEMPERATURE FORECAST. I RAISED THE
FORECAST IN SOME AREAS BASED ON A BLEND OF THE LATEST
GUIDANCE...BUT I THINK IT COULD BE EVEN WARMER IF THE NORTHLAND
GETS ENOUGH SUNSHINE IN THE AFTERNOON. I SIDED A BIT ON THE
CONSERVATIVE SIDE...ESPECIALLY SINCE THERE MAY BE MORNING FOG AND
WE WILL HAVE TO SEE HOW WELL IT CLEARS CONSIDERING LITTLE WIND TO
HELP MIX IT OUT. HOWEVER...IT AT LEAST LOOKS LIKE THE NORTHLAND
WILL FINALLY GET SOME NEAR NORMAL TEMPERATURES AFTER COOLER THAN
NORMAL WEATHER FOR SUCH A LONG TIME.
LONG TERM.../MONDAY NIGHT - SUNDAY/
SURFACE HIGH PRESSURE WITH WEAK MID LEVEL RIDGING WILL MAKE A
RETURN MONDAY NIGHT/TUESDAY. MEANWHILE THE A SHORT WAVE WILL
TRACK EAST ALONG THE INTERNATIONAL BORDER AND INTO THE MN
ARROWHEAD...SWEEPING A TROUGH OVER THE NORTHLAND. LATEST NAM BUFR
SOUNDINGS SHOW VERY DRY PROFILES WITH RAPIDLY FALLING PWATS
THROUGH TUESDAY MORNING...SO HAVE LIMITED POPS TO NRN
ZONES...MAINLY MONDAY NIGHT...AND GONE WITH A DRY FCST OR JUST
MENTION OF SPRINKLES ELSEWHERE TUESDAY.
LONG TERM MODELS ARE IN GOOD OVERALL AGREEMENT THAT A H50 RIDGE
AMPLIFIES OVER THE UPPER MIDWEST LATE THROUGH THE END OF THE WEEK
WITH HIGH PRESSURE BUILDING OVER ONTARIO AND THE WESTERN GREAT
LAKES. TEMPERATURES IN EXTENDED LOOK TO TREND TOWARDS MORE
SEASONABLE VALUES WITH HIGHS IN THE 70S TO NEAR 80. HAVE KEPT A
DRY FCST WED/THURS WITH GRADUALLY INCREASING POPS FROM THE WEST
FRIDAY/SATURDAY AHEAD OF A COLD FRONT.
&&
.POINT TEMPS/POPS...
DLH 53 76 53 75 / 10 10 10 0
INL 53 75 52 75 / 40 10 10 10
BRD 56 79 57 76 / 10 10 10 10
HYR 55 80 56 77 / 10 10 10 10
ASX 50 76 51 72 / 10 10 10 0
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
LS...NONE.
&&
$$
AVIATION...GSF
AREA FORECAST DISCUSSION...UPDATED
NWS GLASGOW MT
937 AM MDT MON JUN 10 2013
.SHORT TERM...FOR NORTHEAST MONTANA...TODAY THROUGH WEDNESDAY...
SENT AN UPDATE THIS MORNING TO CUT BACK POPS NOW THAT THE
PRECIPITATION FROM VERY EARLY THIS MORNING OVER OUR EASTERN AND
NORTHEASTERN ZONES HAS MOVED OUT OF OUR CWA. A VERY CALM AND
COMFORTABLE SPRING DAY EXPECTED ACROSS NORTHEAST MONTANA.
BMICKELSON
PREVIOUS SHORT TERM DISCUSSION...SHOWER ACTIVITY VERY EARLY THIS
MORNING CONTINUES ACROSS EASTERN SECTIONS OF THE FORECAST AREA.
MUCH OF THE MODEL GUIDANCE HAS THIS PUSHING OUT BY 12Z
HOWEVER...RECENT RUNS OF THE HRRR HAVE KEPT SPOTTY SHOWERS AROUND
FOR A FEW MORE HOURS. THUS...TO COVER THIS POTENTIAL INSERTED A
SLIGHT CHANCE POPS MENTION INTO THE GRIDS IN THE EASTERN ZONES.
ANY SHOWERS LEFT OVER FROM EARLY THIS MORNING SHOULD QUICKLY MOVE
OUT AND BECOME REPLACED BY SUNNY SKIES BY THE AFTERNOON AS
NORTHEAST MONTANA BECOMES INFLUENCED BY THE NORTHERN PERIPHERY OF
AN UPPER LEVEL RIDGE. THIS WILL INDUCE LARGE SCALE SUBSIDENCE AND
PREVENT ANY ADDITIONAL SHOWER ACTIVITY FROM FLARING UP. WILL
EXPECT SEASONABLE TEMPERATURES AS WELL WITH THE EARLY JUNE
SUNSHINE GOING TO WORK AND RISING 500MB HEIGHTS WITH THE RIDGING
BUILDING IN.
MONDAY NIGHT...A REGIME OF SOUTHWEST FLOW ALOFT BECOMES
ESTABLISHED OVER NORTHEAST MONTANA AS AN UPPER LEVEL SHORTWAVE
FEATURE TRANSLATES INTO THE AREA. PVA OUT AHEAD OF THIS WAVE AND
UPPER LEVEL DIFFLUENCE WILL PROMOTE FORCED VERTICAL ASCENT. LOW
LEVEL SOUTHEASTERLY FLOW WILL ALSO BRING MOISTURE INTO THE
FORECAST AREA. MODELS CONTINUE TO HAVE DISAGREEMENT HOWEVER ON THE
POTENTIAL FOR SHOWERS/STORMS MONDAY NIGHT INTO TUESDAY APPROACHING
FROM THE SOUTH. THE GFS HAS A BAND IN THE SOUTHERN ZONES
OVERNIGHT...BUT HAS IT DISSIPATING OVER THE AREA ON TUESDAY. THE
ECMWF IS MUCH MORE SUPPORTIVE OF CONVECTION AND GIVEN THE OVERALL
PATTERN AND ARGUMENTS ABOVE LEANED TOWARD THIS SOLUTION FOR NOW
WILL NOTE THAT THE LATEST ECMWF INDICATES GOOD SURFACE CONVERGENCE
IN THE SOUTHWESTERN AND CENTRAL ZONES. THIS LIKELY CORRESPONDS TO
A THERMAL TROUGH THAT EXTENDS FROM A SURFACE LOW EXPECTED TO BE
LOCATED OVER NORTHEAST WYOMING AT THIS TIME. SHOULD CONVECTION
PUSH INTO THE CWA DURING THE DAY ON TUESDAY...THIS TROUGH AXIS
COULD SERVE AS A FOCAL POINT FOR ADDITIONAL CONVECTIVE INITIATION.
WEDNESDAY...AN ADDITIONAL VIGOROUS SHORTWAVE APPROACHES FROM THE
SOUTHWEST WHICH WILL BRING THE NEXT ROUND OF SHOWERS AND
THUNDERSTORMS WITH IT. AS IT PUSHES INTO A NICE THETA-E RIDGE THAT
SETS UP ACROSS THE SOUTHWESTERN ZONES. THE LATEST 00Z MODEL GUIDANCE
INDICATES THAT THE BEST CHANCES FOR CONVECTIVE INITIATION WOULD BE
ACROSS WESTERN/CENTRAL ZONES. THE LATEST ECMWF HAS UPWARDS OF 1500
J/KG OF CAPE...WITH THE GFS A LITTLE MORE ROBUST. FORECAST
SOUNDINGS ALSO SHOW A NICE VEERING WIND PROFILE INDICATING PLENTY
OF DIRECTIONAL WIND SHEAR. THIS WILL COMBINE WITH UPPER LEVEL
DIFFLUENCE AND LOW LEVEL MOISTURE TO PRODUCE A GOOD POTENTIAL FOR
CONVECTION. GIVEN PRECIPITABLE WATER VALUES OF OVER AN
INCH...LOCALLY HEAVY RAINFALL WILL BE POSSIBLE. THE ECMWF SOLUTION
IS MUCH FURTHER WEST...WITH THE GFS MORE AGGRESSIVE BRINGING THE
PRECIPITATION CHANCES THROUGH MOST OF THE CWA BY 00Z THURSDAY.
GIVEN THESE DIFFERENCES...WAS NOT CONFIDENT ENOUGH JUST YET TO
INSERT A MENTION OF HEAVY RAIN INTO THE GRIDS JUST YET...BUT A
WETTING RAIN IS CERTAINLY POSSIBLE WITH THESE STORMS...ESPECIALLY
IN THE WEST. WILL LET THE DAY SHIFT EVALUATE THAT MORE CLOSELY AND
SEE IF THERE IS DECENT MODEL CONTINUITY OR IF SOLUTIONS ARE LINING
UP BETTER. AM CONCERNED ABOUT CAPPING INVERSION IN THE CENTRAL AND
EASTERN ZONES AS THERE IS UPWARDS OF 200-400 J/KG OF CIN PRESENT
IN SOME OF THE GUIDANCE. THIS LENDS FURTHER SUPPORT TO THE IDEA OF
THE BEST CHANCES BEING ACROSS THE WEST...AT LEAST INITIALLY. NOTE
THAT BEST LOW LEVEL CONVERGENCE ACROSS THE WESTERN ZONES DURING
THE DAY ON WEDNESDAY IS DEPICTED TO SHIFT EASTWARD BY THE LATE
AFTERNOON. THUS...STORMS MAY INITIATE ACROSS THE WEST AND THEN
PUSH EASTWARD. IT IS NOTEWORTHY THAT GIVEN HEAVY RAINFALL
POTENTIAL WITH ANY STORMS THAT DO DEVELOP...FUTURE SHIFTS WILL
NEED TO EVALUATE THE FLOODING POTENTIAL DUE TO RECENT RAINFALL
OVER THE LAST COUPLE OF WEEKS. MALIAWCO
.LONG TERM...WEDNESDAY NIGHT THROUGH MONDAY...
THE EXTENDED WITH THE 00Z SUITE OF MODELS IN KEEPS THE AREA IN A
VERY TYPICAL JUNE PATTERN THROUGH THE WHOLE PERIOD. WHICH LEADS TO
A HIGH LEVEL OF PREDICTABILITY OF THE PATTERN...HOWEVER IT ALL
WILL BE IN THE TIMING OF INDIVIDUAL WAVES MOVING THROUGH THE FLOW
FOR THUNDERSTORM CHANCES. CLIMO POP FOR THIS TIME OF YEAR IS AT
ITS HIGHEST WITH CHANCE LEVEL POPS.
WEDNESDAY NIGHT...SOUTHWEST FLOW ALOFT AND SURFACE TROUGH TO THE
WEST SHOULD SET UP FOR A FEW THUNDERSTORMS ACROSS THE AREA. UPPER
LEVEL SUPPORT IS NOT THAT GREAT FOR SEVERE TYPE CONVECTION.
THURSDAY-THURSDAY NIGHT BRINGS MORE OF THE SAME...EC DOES HINT THAT WE
COULD GET A LITTLE JET DYNAMICS TO HELP OUT FOR A CHANCE FOR SOME
STRONGER THUNDER.
FRIDAY-FRIDAY NIGHT...SURFACE TROUGH PUSHES EAST WITH GOOD DRYING
ALOFT SO WILL RELAX BACK BELOW CLIMO FOR POPS.
SATURDAY-SATURDAY NIGHT...PREFER THE EC OVER THE GFS KEEPING
NORTHEAST MONTANA MOSTLY DRY...STILL CYCLONIC FLOW COULD HAVE AN
ISOLATED THUNDERSTORM OUT THERE.
SUNDAY-SUNDAY NIGHT...RIDGING ALOFT SHOULD KEEP ANY THUNDER
ACTIVITY LIMITED FOR THE REGION.
MONDAY-MONDAY NIGHT...PATTERN STARTS BACK INTO THE SOUTHWEST FLOW
ALOFT...SURFACE SOUTHEAST FLOW FOR CHANCE OF CONVECTION AGAIN.
TEMPERATURES FAIRLY SEASONAL THROUGH THE WHOLE PERIOD. PROTON
&&
.AVIATION...
VFR. A SMALL CHANCE EXISTS THIS AFTERNOON SOUTH OF THE MISSOURI
RIVER FOR SOME BRIEF THUNDER... OTHERWISE A GOOD FLYING DAY FOR
NORTHEAST MONTANA EXPECTED. PROTON
&&
.HYDROLOGY...
FLOOD WARNINGS REMAIN IN EFFECT FOR PORTIONS OF THE MILK RIVER
DRAINAGE BASIN STRETCHING FROM TAMPICO TO THE EAST SIDE OF
GLASGOW.
THE MILK RIVER CRESTING AT SACO. IT IS HOLDING STEADY OR EXPECTED
TO CREST OVER THE NEXT FEW DAYS AT THE DOWNSTREAM LOCATIONS OF
TAMPICO... GLASGOW AND NASHUA.
RUNOFF FROM EARLIER RAINS IS STILL WORKING ITS WAY DOWN BEAVER
CREEK IN PHILLIPS COUNTY SOUTH OF SACO. THE GAGE SITE NEAR GUSTON
COULEE SOUTHWEST OF SACO IS JUST BELOW THE FLOOD STAGE OF 11
FEET AND FALLING VERY SLOWLY. A FLOOD WARNING CONTINUES FOR BEAVER
CREEK.
ANOTHER ROUND OF HEAVY RAIN IS POSSIBLE MIDWEEK WHICH COULD
CREATE ADDITIONAL FLOODING PROBLEMS ACROSS NORTHEAST MONTANA FOR
LATE THIS WEEK. EBERT
&&
.GLASGOW WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
WEATHER.GOV/GLASGOW
AREA FORECAST DISCUSSION
NWS GLASGOW MT
405 AM MDT MON JUN 10 2013
.SHORT TERM...FOR NORTHEAST MONTANA...TODAY THROUGH WEDNESDAY...
SHOWER ACTIVITY VERY EARLY THIS MORNING CONTINUES ACROSS EASTERN
SECTIONS OF THE FORECAST AREA. MUCH OF THE MODEL GUIDANCE HAS THIS
PUSHING OUT BY 12Z HOWEVER...RECENT RUNS OF THE HRRR HAVE KEPT
SPOTTY SHOWERS AROUND FOR A FEW MORE HOURS. THUS...TO COVER THIS
POTENTIAL INSERTED A SLIGHT CHANCE POPS MENTION INTO THE GRIDS IN
THE EASTERN ZONES. ANY SHOWERS LEFT OVER FROM EARLY THIS MORNING
SHOULD QUICKLY MOVE OUT AND BECOME REPLACED BY SUNNY SKIES BY THE
AFTERNOON AS NORTHEAST MONTANA BECOMES INFLUENCED BY THE NORTHERN
PERIPHERY OF AN UPPER LEVEL RIDGE. THIS WILL INDUCE LARGE SCALE
SUBSIDENCE AND PREVENT ANY ADDITIONAL SHOWER ACTIVITY FROM FLARING
UP. WILL EXPECT SEASONABLE TEMPERATURES AS WELL WITH THE EARLY
JUNE SUNSHINE GOING TO WORK AND RISING 500MB HEIGHTS WITH THE
RIDGING BUILDING IN.
MONDAY NIGHT...A REGIME OF SOUTHWEST FLOW ALOFT BECOMES
ESTABLISHED OVER NORTHEAST MONTANA AS AN UPPER LEVEL SHORTWAVE
FEATURE TRANSLATES INTO THE AREA. PVA OUT AHEAD OF THIS WAVE AND
UPPER LEVEL DIFFLUENCE WILL PROMOTE FORCED VERTICAL ASCENT. LOW
LEVEL SOUTHEASTERLY FLOW WILL ALSO BRING MOISTURE INTO THE
FORECAST AREA. MODELS CONTINUE TO HAVE DISAGREEMENT HOWEVER ON THE
POTENTIAL FOR SHOWERS/STORMS MONDAY NIGHT INTO TUESDAY APPROACHING
FROM THE SOUTH. THE GFS HAS A BAND IN THE SOUTHERN ZONES
OVERNIGHT...BUT HAS IT DISSIPATING OVER THE AREA ON TUESDAY. THE
ECMWF IS MUCH MORE SUPPORTIVE OF CONVECTION AND GIVEN THE OVERALL
PATTERN AND ARGUMENTS ABOVE LEANED TOWARD THIS SOLUTION FOR NOW
WILL NOTE THAT THE LATEST ECMWF INDICATES GOOD SURFACE CONVERGENCE
IN THE SOUTHWESTERN AND CENTRAL ZONES. THIS LIKELY CORRESPONDS TO
A THERMAL TROUGH THAT EXTENDS FROM A SURFACE LOW EXPECTED TO BE
LOCATED OVER NORTHEAST WYOMING AT THIS TIME. SHOULD CONVECTION
PUSH INTO THE CWA DURING THE DAY ON TUESDAY...THIS TROUGH AXIS
COULD SERVE AS A FOCAL POINT FOR ADDITIONAL CONVECTION INITIATION.
WEDNESDAY...AN ADDITIONAL VIGOROUS SHORTWAVE APPROACHES FROM THE
SOUTHWEST WHICH WILL BRING THE NEXT ROUND OF SHOWERS AND
THUNDERSTORMS WITH IT. AS IT PUSHES INTO A NICE THETA-E RIDGE THAT
SETS UP ACROSS THE SOUTHWESTERN ZONES. THE LATEST 00Z MODEL GUIDANCE
INDICATES THAT THE BEST CHANCES FOR CONVECTION INITIATION WOULD BE
ACROSS WESTERN/CENTRAL ZONES. THE LATEST ECMWF HAS UPWARDS OF 1500
J/KG OF CAPE...WITH THE GFS A LITTLE MORE ROBUST. FORECAST
SOUNDINGS ALSO SHOW A NICE VEERING WIND PROFILE INDICATING PLENTY
OF DIRECTIONAL WIND SHEAR. THIS WILL COMBINE WITH UPPER LEVEL
DIFFLUENCE AND LOW LEVEL MOISTURE TO PRODUCE A GOOD POTENTIAL FOR
CONVECTION. GIVEN PRECIPITABLE WATER VALUES OF OVER AN
INCH...LOCALLY HEAVY RAINFALL WILL BE POSSIBLE. THE ECMWF SOLUTION
IS MUCH FURTHER WEST...WITH THE GFS MORE AGGRESSIVE BRINGING THE
PRECIPITATION CHANCES THROUGH MOST OF THE CWA BY 00Z THURSDAY.
GIVEN THESE DIFFERENCES...WAS NOT CONFIDENT ENOUGH JUST YET TO
INSERT A MENTION OF HEAVY RAIN INTO THE GRIDS JUST YET...BUT A
WETTING RAIN IS CERTAINLY POSSIBLE WITH THESE STORMS...ESPECIALLY
IN THE WEST. WILL LET THE DAY SHIFT EVALUATE THAT MORE CLOSELY AND
SEE IF THERE IS DECENT MODEL CONTINUITY OR IF SOLUTIONS ARE LINING
UP BETTER. AM CONCERNED ABOUT CAPPING INVERSION IN THE CENTRAL AND
EASTERN ZONES AS THERE IS UPWARDS OF 200-400 J/KG OF CIN PRESENT
IN SOME OF THE GUIDANCE. THIS LENDS FURTHER SUPPORT TO THE IDEA OF
THE BEST CHANCES BEING ACROSS THE WEST...AT LEAST INITIALLY. NOTE
THAT BEST LOW LEVEL CONVERGENCE ACROSS THE WESTERN ZONES DURING
THE DAY ON WEDNESDAY IS DEPICTED TO SHIFT EASTWARD BY THE LATE
AFTERNOON. THUS...STORMS MAY INITIATE ACROSS THE WEST AND THEN
PUSH EASTWARD. IT IS NOTEWORTHY THAT GIVEN HEAVY RAINFALL
POTENTIAL WITH ANY STORMS THAT DO DEVELOP...FUTURE SHIFTS WILL
NEED TO EVALUATE THE FLOODING POTENTIAL DUE TO RECENT RAINFALL
OVER THE LAST COUPLE OF WEEKS. MALIAWCO
.LONG TERM...WEDNESDAY NIGHT THROUGH MONDAY...
THE EXTENDED WITH THE 00Z SUITE OF MODELS IN KEEPS THE AREA IN A
VERY TYPICAL JUNE PATTERN THROUGH THE WHOLE PERIOD. WHICH LEADS TO
A HIGH LEVEL OF PREDICTABILITY OF THE PATTERN...HOWEVER IT ALL
WILL BE IN THE TIMING OF INDIVIDUAL WAVES MOVING THROUGH THE FLOW
FOR THUNDERSTORM CHANCES. CLIMO POP FOR THIS TIME OF YEAR IS AT
ITS HIGHEST WITH CHANCE LEVEL POPS.
WEDNESDAY NIGHT...SOUTHWEST FLOW ALOFT AND SURFACE TROUGH TO THE
WEST SHOULD SET UP FOR A FEW THUNDERSTORMS ACROSS THE AREA. UPPER
LEVEL SUPPORT IS NOT THAT GREAT FOR SEVERE TYPE CONVECTION.
THURSDAY-THURSDAY NIGHT BRINGS MORE OF THE SAME...EC DOES HINT THAT WE
COULD GET A LITTLE JET DYNAMICS TO HELP OUT FOR A CHANCE FOR SOME
STRONGER THUNDER.
FRIDAY-FRIDAY NIGHT...SURFACE TROUGH PUSHES EAST WITH GOOD DRYING
ALOFT SO WILL RELAX BACK BELOW CLIMO FOR POPS.
SATURDAY-SATURDAY NIGHT...PREFER THE EC OVER THE GFS KEEPING
NORTHEAST MONTANA MOSTLY DRY...STILL CYCLONIC FLOW COULD HAVE AN
ISOLATED THUNDERSTORM OUT THERE.
SUNDAY-SUNDAY NIGHT...RIDGING ALOFT SHOULD KEEP ANY THUNDER
ACTIVITY LIMITED FOR THE REGION.
MONDAY-MONDAY NIGHT...PATTERN STARTS BACK INTO THE SOUTHWEST FLOW
ALOFT...SURFACE SOUTHEAST FLOW FOR CHANCE OF CONVECTION AGAIN.
TEMPERATURES FAIRLY SEASONAL THROUGH THE WHOLE PERIOD. PROTON
&&
.AVIATION...
VFR. A SMALL CHANCE EXISTS THIS AFTERNOON SOUTH OF THE MISSOURI
RIVER FOR SOME BRIEF THUNDER... OTHERWISE A GOOD FLYING DAY FOR
NORTHEAST MONTANA EXPECTED. PROTON
&&
.GLASGOW WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
WEATHER.GOV/GLASGOW
AREA FORECAST DISCUSSION
NWS GREAT FALLS MT
1057 PM MDT Sun Jun 9 2013
UPDATE TO AVIATION
.DISCUSSION...
Update forthcoming. Generally quiet and benign conditions expected
overnight. The exception to this picture, as was the case last
night, is weak short wave energy moving along the Canadian border
and additional short wave energy over portions of southwest Montana.
An isolated thunderstorm is possible over these areas. HRRR analysis
suggests this activity should end by 07z. Temperatures look
reasonable but have tweaked lows for Great Falls and Lewistown.
Emanuel
&&
.AVIATION...
Updated 0457Z.
VFR conditions will continue across north central/central/southwest
Montana at least through Monday evening. Skies will remain mostly
clear across the area into early Monday afternoon. However, light
northerly upslope winds will keep an area of mid level cloudiness
(around 5000 feet AGL) north and west of a line from KGTF to KHVR
until 12Z or so. The airmass becomes weakly unstable again across
southwest Montana after 21Z Monday as a disturbance approaches the
area, for a chance of thunderstorms there, possibly impacting the
KBZN terminal. Coulston
&&
.PREV DISCUSSION...Issued 256 PM MDT Sun Jun 9 2013
Tonight through Tuesday...Generally quiet but breezy weather will
continue this evening. However, once again this evening, there
will be a slight chance of a shower or thunderstorm at opposite
ends of the CWA: near the Canadian border and near Yellowstone
Park. On Monday, an upper level wave will move through the Great
Basin with flow aloft over the CWA backing around to the southwest
by evening. The airmass also becomes unstable over far southwest
Montana during the afternoon and evening with scattered
thunderstorms developing over the mountains. This convection
will move to the northeast into central Montana overnight and
expand in coverage. There is also some indication that a mesoscale
complex could form over central Montana during the overnight
hours. Showers and thunderstorms become likely across much of the
forecast area on Tuesday. From Tuesday evening through Wednesday
afternoon there is some risk that a few thunderstorms may become
strong to borderline severe with gusty winds being the main
threat. mpj
Tuesday night through Sunday...a rather unsettled weather pattern
will reside over the region from much of the second half of the work
week. A rather strong upper level disturbance is expected to develop
over Central MT early Tue evening. Some of the storms could be on
the strong side Tue evening. Thus pops have been raised for a good
portion of North Central MT. Another round of storms will affect the
region Wednesday into Thursday ahead the main cold front and upper
level trof. Expect the precipitation to become a bit more widespread
by Thursday over North Central MT. This heavier precip later in the
week will slow down the rivers receding in Hill and Blaine
counties. Colder air will move into the region by Thursday
night...thus snow levels will be lowering into the 6500 to 7500 feet
range. Expect some snow at higher elevations by Friday morning...but
any snow accumulations should be minor. For Saturday...expect drier
near seasonable temperatures to move back into the region. By next
Sunday...a southwesterly flow develop aloft resulting in a chance
for afternoon thunderstorms over Central and Southwest MT by late in
the day. Brusda
&&
.HYDROLOGY...
Small streams and creeks remain high and out of their banks across a
large portion of Central and North Central Montana. Areal flood
warnings will continue for Hill/Blaine/Fergus Counties. Point flood
warnings remain in effect for three locations: Big Sandy Creek near
Havre, Clear Creek near Chinook, and the Milk River near Harlem.
These points are expected to remain near or above flood stage into
at least the early part of this week. The potential exists Tuesday
for significant rain over areas currently under flood warnings.
&&
.PRELIMINARY POINT TEMPS/POPS...
GTF 47 74 48 72 / 0 0 30 40
CTB 41 71 44 70 / 10 10 10 40
HLN 49 79 50 77 / 0 10 30 40
BZN 45 81 47 77 / 10 20 30 50
WEY 42 78 41 71 / 20 30 30 40
DLN 48 82 49 76 / 0 30 40 50
HVR 46 74 49 72 / 10 0 20 50
LWT 46 72 48 69 / 0 0 40 70
&&
.TFX WATCHES/WARNINGS/ADVISORIES...
Flood Warning through Monday morning for Blaine, Fergus, and Hill
Counties.
Flood Warning until further notice for Big Sandy Creek near
Havre, Clear Creek near Chinook, and the Milk River near Harlem.
&&
$$
weather.gov/greatfalls
AREA FORECAST DISCUSSION...UPDATED
NWS OMAHA/VALLEY NE
930 PM CDT TUE JUN 11 2013
.DISCUSSION...
00Z 700 MB CHART SHOWED VERY WARM TEMPS IN PLACE (+18 C AT KLBF
AND +15 C AT KOAX) WHICH WILL TEND TO LIMIT SOUTHWARD COVERAGE OF
STRONGEST STORMS. RECENT RUNS OF THE HRRR SEEM TO HAVE A DECENT
HANDLE ON SCENARIO (COMPARED TO MOST RECENT RADAR RETURNS) WHICH
SHOW AN MCS PUSHING ACROSS NERN NE AS SHORTWAVE ENERGY MOVES OVER
TOP OF THE MID TROPOSPHERIC RIDGE.
MADE SOME MINOR CHANGES TO THE OVERNIGHT PERIOD...MAINLY TO
INCREASE TSTM CHANCES ACROSS THE NRN ZONES AND TO DECREASE THEM
SLIGHTLY IN THE SRN ZONES. INCLUDED MENTION OF GUSTY WINDS OVER
NERN NE. ALSO INCREASED QPF SLIGHTLY. ANY OTHER CHANGES WERE
VERY MINOR.
MILLER
&&
.PREV DISCUSSION... /ISSUED 655 PM CDT TUE JUN 11 2013/
AVIATION...00Z TAFS FOR KOFK...KOMA AND KLNK.
MAIN AVN CONCERNS ARE FOCUSED AT KOFK. TSRA WILL LIKELY DEVELOP
THIS EVENING IN WRN NEB THEN MIGRATE NE INTO NERN NEB TWD
MIDNIGHT ALONG A NEAR-STATIONARY SFC BNDRY. EXPECT TS ACTIVITY TO
ROLL THRU KOFK THEN BTWN 05Z-09Z. AFT 09Z...LLVL MOISTURE IN PLACE
WILL LIKELY RESULT IN MVFR CIGS UNTIL COLD FRONT PUSHES THRU
AROUND 14Z WED MORNING. NW WIND GUSTS AROUND 25KT WITH THEN
PREVAIL THRU THE REST OF THE FCST PD. AS FOR KOMA/KLNK...THOSE
TERMINALS SHOULD BE SPARED FROM ANY TS ACTIVITY COLD FRONTAL
PASSAGE COMING SOMETIME AROUND 16Z. BOTH SITES ALONG WILL HAVE
WIND GUSTS AROUND 20KT AFTER THE FRONTAL PASSAGE.
DEE
PREV DISCUSSION... /ISSUED 315 PM CDT TUE JUN 11 2013/
DISCUSSION...
MAIN FORECAST CONCERN WILL BE OVERNIGHT THUNDERSTORMS...AND THEN
CONTINUED CHANCES OF THUNDERSTORMS THROUGH THE FORECAST.
UPPER RIDGE HAS BUILT OVER THE CENTRAL PLAINS WITH AN EMBEDDED
SHORTWAVE TROUGH AXIS TO THE WEST EXTENDING FROM SOUTH WESTERN
WYOMING AND NORTHWESTERN COLORADO. AT THE SFC...A WARM FRONT EXTENDS
FROM AN AREA OF SFC LOW PRESSURE IN NORTHEAST COLORADO/NORTHWEST
KANSAS NORTHEAST TO SOUTHWEST IOWA. SFC DEWPOINTS CONTINUE TO POOL
INTO THE LOW 70S NEAR THE BOUNDARY GENERATING QUITE MUGGY
CONDITIONS. SCATTERED WEAK/ELEVATED CONVECTION HAS CONTINUED NEAR
THIS BOUNDARY MUCH OF THE DAY AND HAS REALLY LIMITED MAX HEATING
POTENTIAL. NEAR TERM CONVECTIVE PRODUCING MODELS CONTINUE THIS
ACTIVITY INTO THE EVENING HOURS BEFORE MOVING IT EAST LATER THIS
EVENING.
CONVECTION IS EXPECTED TO DEVELOP OVER THE HIGH PLAINS THIS EVENING
ASSOCIATED WITH THE ABOVE MENTIONED SHORTWAVE TROUGH IN A VERY
UNSTABLE AIRMASS. THIS ACTIVITY WILL LIKELY AND ROLL EAST AS AN
MCS OVERNIGHT AND PUSH INTO OUR CWA OVERNIGHT.
A FEW LINGERING SHOWERS ARE POSSIBLE WEDNESDAY MORNING BUT SHOULD
ROLL OUT OF THE AREA BY LATE MORNING AS THE SYSTEM MARCHES EAST.
COOLER TEMPERATURES ARE EXPECTED ON WEDNESDAY UNDER THE INFLUENCE OF
NORTHERLY LOW LEVEL FLOW. HIGH SHOULD STILL TOP OUT IN THE LOWER TO
MID 80S ACROSS MUCH OF THE AREA.
UPPER RIDGING BUILDS BACK INTO THE REGION FAIRLY QUICKLY ON
THURSDAY. ANOTHER ROUND OF NOCTURNAL THUNDERSTORMS LOOKS POSSIBLE
THURSDAY NIGHT INTO FRIDAY AS ANOTHER SHORTWAVE TROUGH RIDES OVER
THE UPPER RIDGE AND AGAIN FRIDAY NIGHT INTO SATURDAY.
THE UPPER FLOW FLATTENS BY SUNDAY WITH A SFC BOUNDARY PROGGED TO
EXTEND OVER THE CWA. WILL CONTINUE CHANCE POPS INTO SUNDAY AS ANY
WEAK SHORTWAVE TRAVELING THROUGH THIS ZONAL FLOW COULD SPAWN SHOWERS
AND THUNDERSTORMS. SLIGHTLY COOLER TEMPS LOOK POSSIBLE INTO DAY 7 AS
UPPER FLOW BECOMES MORE NORTHWESTERLY WITH A LARGE RIDGE BUILDING TO
OUR WEST.
KERN
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
650 PM CDT TUE JUN 11 2013
.MESOSCALE DISCUSSION...
ISSUED AT 647 PM CDT TUE JUN 11 2013
SURFACE ANALYSIS AT 21Z SHOWED A FRAGMENTED FRONT/BOUNDARY ACROSS
NORTHEAST COLORADO AND SOUTHWEST NEBRASKA AND ACROSS EASTERN WYOMING
INTO THE PANHANDLE OF NEBRASKA. RADARS SHOWED A BOUNDARY ACROSS
NORTHERN NEBRASKA BETWEEN THEDFORD AND VALENTINE AND ANOTHER EAST OF
CHEYENNE AND DENVER BUT WEST OF SCOTTSBLUFF AND STERLING. CONVECTIVE
POTENTIAL IN THE LAPS DATA IS OVER 3000J/KG IN MUCH OF WESTERN AND
NORTHERN NEBRASKA WITH 0-6KM BULK SHEAR 45-55KT. STORMS MOVING
NORTHEASTWARD ALONG THE BOUNDARY IN NORTH CENTRAL NEBRASKA ARE
MOVING INTO MOST HIGHEST CONVECTIVE ENERGY AREAS AND ALSO INTO
HIGHER EFFECTIVE HELICITY. EXPLOSIVE INTENSIFICATION IS POSSIBLE
ALONG THAT BAND OF CONVECTION. THE NETWORK PROFILER AT MERRIMAN
SHOWS SOME VEERING WIND ABOVE 0.5KM AGL AND 0-6KM BULK SHEAR OF 60K.
THIS IS BORNE OUT IN THE RADAR PROFILERS FROM RAPID CITY AND
THEDFORD NEBRASKA. VISIBLE SATELLITE AND RADAR MOSAIC INDICATE SOME
CONVECTIVE INITIATION OCCURRING OVER THE NEBRASKA PANHANDLE AND OVER
THE WESTERN NEBRASKA SANDHILLS.
&&
.SYNOPSIS...
ISSUED AT 300 PM CDT TUE JUN 11 2013
H5 ANALYSIS THIS MORNING...AS A RIDGE EXTENDING FROM
TEXAS...NORTH INTO THE EASTERN DAKOTAS. WEST OF THE RIDGE...A STRONG
SHORTWAVE WAS LOCATED OVER NORTHERN NEVADA WITH A CLOSED LOW NOTED
OFF THE COAST OF BRITISH COLUMBIA. WV IMAGERY AS OF 18Z HAS THE NRN
NEVADA SHORTWAVE...ENTERING FAR SWRN WYOMING. LIGHTNING STRIKES
AND CONVECTION HAS DEVELOPED ACROSS SWRN MT AND NWRN WYOMING IN
ADVANCE OF THIS FEATURE. AT THE SURFACE A FRONTAL BOUNDARY
EXTENDED FROM CENTRAL WYOMING...SE INTO NRN COLORADO...THEN EAST
INTO SRN NEBRASKA. ALONG AND SOUTH OF THIS BOUNDARY...TEMPERATURES
HAVE SURGED INTO THE UPPER 90S AND LOWER 100S. NORTH OF THE
BOUNDARY...TEMPERATURES WERE IN 80S. DEEP EASTERLY FLOW WAS
PRESENT NORTH OF THE FRONT AND HAS PUSHED DEW POINTS INTO THE
UPPER 50S TO UPPER 60S THIS AFTERNOON...WITH THE HIGHEST DEW
POINTS NOTED OVER NORTHERN NEBRASKA. AS OF 2 PM CDT DEW
POINTS...RANGED FROM 63 AT PINE RIDGE...TO 68 AT ONEILL.
&&
.SHORT TERM...(THIS AFTERNOON THROUGH WEDNESDAY)
ISSUED AT 300 PM CDT TUE JUN 11 2013
TONIGHT AND WEDNESDAY...MAIN FORECASTING CHALLENGE IS
THUNDERSTORM CHANCES AND SEVERE POTENTIAL TONIGHT. TOWARD 00Z THIS
EVENING...A DECENT SHORTWAVE WILL APPROACH THE PANHANDLE WITH TSRA
INITIATION DURING THE 22Z TO 00Z TIME FRAME. THE HI RES RUC...AS
WELL AS THE 12Z NAM SOLN...DEVELOPS ISOLD TSRAS IN THE NERN
PANHANDLE...AND SWRN NEBRASKA AROUND 22Z THIS AFTERNOON. ACTIVITY IN
THE SWRN CWA SHEARS OFF AND DISSIPATES QUICKLY BY 01Z. FURTHER
NORTH...ACTIVITY IS EXPECTED TO PERSIST INTO THE EVENING HOURS...DUE
TO A COMBINATION OF BETTER SUPPORT ALOFT AND DEEPER...RICHER
BOUNDARY LAYER MOISTURE IN NORTHERN NEBRASKA...WHERE DEWPOINTS WILL
REACH THE MID 60S TO AROUND 70 BY THIS EVENING. A TORNADO THREAT
WILL EXIST INITIALLY IN THE NWRN CWA WITH DECENT DEEP LAYER
SHEAR...LOWERED LCL HTS...AND THE PRESENCE OF A WEAK LOW LEVEL
BOUNDARY. BASED ON THE LATEST HRRR AND 4KM WRF
SOLNS...SHERIDAN...AND WESTERN CHERRY COUNTIES HAVE THE HIGHEST RISK
OF SEEING A DISCRETE SUPERCELL...AND THUS THE HIGHEST TORNADO THREAT
EARLY THIS EVENING. THE TORNADO THREAT WILL DECREASE BY MID EVENING
AS A STRONG FAST MOVING MCS DEVELOPS OVER THE BLACK HILLS AND RACES
EAST OVERNIGHT. THE THREAT FOR STRONG DAMAGING WINDS WILL BE HIGHEST
ACROSS FAR NORTHERN NEBRASKA INTO THE OVERNIGHT AS THIS WILL BE ON
THE SRN PERIPHERY OF THE MCS. AS THE MCS TRACKS INTO SRN MN/NRN IA
OVERNIGHT TONIGHT...A COLD FRONT WILL DROP SOUTH INTO WESTERN AND
NORTH CENTRAL NEBRASKA...WITH HIGH PRESSURE BUILDING INTO NERN
NEBRASKA FOR WEDNESDAY. COOLER TEMPS AND PARTLY TO MOSTLY CLOUDY
SKIES WILL PUSH INTO NERN AND CENTRAL PORTIONS OF THE FORECAST AREA
WEDNESDAY WITH HIGHS RANGING FROM THE UPPER 70S TO MIDDLE 80S.
ACROSS FAR SWRN NEBRASKA...HIGHS WILL TOP OUT NEAR 90.
.LONG TERM...(WEDNESDAY NIGHT THROUGH MONDAY)
ISSUED AT 300 PM CDT TUE JUN 11 2013
MODELS HAVE COME INTO BETTER AGREEMENT IN MID AND LONG TERM
FORECASTS. HEAT TO HANG AROUND WITH SUMMER BEGINNING EARLY. STRONG
RIDGE OVER SOUTHERN INTO NORTHERN PLAINS WILL KEEP JET STREAM WELL
NORTH. H5 SYSTEMS MOVING OUT OF THE GULF OF ALASKA WILL TRY TO
FLATTEN RIDGE OVER NORTHERN PLAINS BUT MAIN ENERGY WILL BE PUSHED
TO THE CANADIAN US BORDER WITH WEAKER WAVES MOVING UNDER THE
RIDGE. WITH AFTERNOON HEATING AND INSTABILITY INCREASING LATE
AFTERNOON THUNDERSTORMS FIRING ALONG THE FRONT RANGE AND MOVING
EAST INTO WESTERN NEBRASKA IN A RING OF FIRE PATTERN. NAM HAS BEEN
HANDLING HEAT FAR BETTER THAN OTHER MODELS AS OF LATE AND WILL
LEAN TOWARDS NAM SOLUTIONS AS FAR AS HIGH TEMPERATURES. SURFACE
HIGH PRESSURE BUILDING INTO WESTERN NEBRASKA WEDNESDAY EVENING. SOME
CLEARING HAVE KEPT TEMPERATURES IN THE MID TO UPPER 50S WITH 15C
850MB TEMPERATURES OVER HEAD. WARM AIR ADVECTION OVER WESTERN
NEBRASKA THROUGH THE DAY ON THURSDAY. UPSLOPE FLOW AND WAVE
MOVING THROUGH HAVE RETAINED POPS. FRIDAY LOOKS TO WARM UP INTO
THE 90S ONCE AGAIN WITH SOME WARMER TEMPERATURES OVER SOUTHWEST
NEBRASKA NEAR IMPERIAL. 850MB TEMPS 30C AND GREATER ONCE AGAIN.
THUNDERSTORMS TO LINGER INTO THE DAY ON FRIDAY WITH BOUNDARY LYING
ACROSS FORECAST AREA. WARM TEMPERATURES AT 700MB INDICATIVE OF
STRONG CAP AND POPS MAY HAVE TO BE REDUCED IN LATER FORECASTS.
EVEN WITH COOLER TEMPERATURES SATURDAY BEHIND FRONT BOUNDARY
CONTINUES TO LAY ACROSS FORECAST AREA AND STRONG MOISTURE
ADVECTION HAVE RETAINED THUNDERSTORMS LATE AFTERNOON AND EVENING.
THUNDERSTORMS IN THE FORECAST AGAIN ON SUNDAY AS SYSTEM DROPS OUT
OF CANADA ACROSS MINNESOTA. BETTER CHANCES OVER EASTERN PORTIONS
OF THE FORECAST AREA. NORMAL TEMPERATURES IN THE 80S THROUGH THE
FIRST PART OF THE WORK WEEK WITH CHANCES FOR THUNDERSTORMS MAINLY
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING)
ISSUED AT 647 PM CDT TUE JUN 11 2013
SHOWERS AND THUNDERSTORMS ARE SLOW TO DEVELOP THIS AFTERNOON.
HOWEVER...AT LEAST TWO SHORT RANGE SIMULATIONS SHOW A STORM SYSTEM
DEVELOPING IN WESTERN NEBRASKA AND CROSSING THROUGH CENTRAL NEBRASKA
AND INTO THE NORTHEAST THIS EVENING. THERE IS SOME AGREEMENT THAT
THEY WILL PASS BETWEEN IML-LBF AND VTN-ANW. THE PROBABILITY OF
THUNDER AT VTN IS SLIGHTLY HIGHER THAN AT LBF. THIS WILL BE
REFLECTED IN THE TERMINAL FORECASTS FOR THOSE SITES. STRONG VARIABLE
WIND AND HAIL CAN BE EXPECTED IN THE VICINITY OF THUNDERSTORMS.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
MESOSCALE...SPRINGER
SYNOPSIS...CLB
SHORT TERM...CLB
LONG TERM...POWER
AVIATION...SPRINGER
AREA FORECAST DISCUSSION
NWS HASTINGS NE
614 PM CDT TUE JUN 11 2013
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 350 PM CDT TUE JUN 11 2013
AN UPPER LEVEL DISTURBANCE CROSSING THE INTERMOUNTAIN WEST THIS
AFTERNOON WILL CONTINUE TO TRANSITION AND CUT INTO THE UPPER LEVEL
RIDGE ON WEDNESDAY...HELPING TO STEER A WEAK COLD FRONT TO OUR NORTH
ACROSS THE LOCAL AREA OVERNIGHT TONIGHT. AS A RESULT...EXPECT
AFTERNOON TEMPERATURES TO FALL SIGNIFICANTLY ACROSS MUCH OF THE
LOCAL AREA ON WEDNESDAY...RETURNING TO NEAR OR JUST ABOVE
CLIMATOLOGICAL VALUES.
IN THE MEANTIME...ALREADY SEEING A COUPLE OF SHOWERS DEVELOP
ACROSS NORTHWESTERN KANSAS THIS AFTERNOON...WHICH ARE EXPECTED TO
SLOWLY DRIFT TOWARDS THE LOCAL AREA LATE THIS AFTERNOON AND
EVENING. WHILE A SIGNIFICANT CAP REMAINS IN PLACE...PLENTY OF
INSTABILITY EXISTS IF A FEW STORMS ARE ABLE TO DEVELOP FOR SOME
STRONG WIND GUSTS AND POSSIBLY MARGINALLY SEVERE HAIL...SOME OF
WHICH IS CAPTURED BY LATEST HRRR AND 12Z WRF. EVEN SO...THE BEST
CHANCE FOR DEVELOPMENT...SEVERE OR OTHERWISE...IS EXPECTED TO BE
ACROSS THE NORTHERN TIER OF COUNTIES OVERNIGHT...AS THIS AREA WILL
BE NEAR THE APPROACHING COLD FRONT AND IN THE AXIS OF THE
DEVELOPING LOW LEVEL JET. SO WHILE THE SEVERE POTENTIAL WILL BE
FOCUSED PRIMARILY WEST OF HIGHWAY 281 LATE THIS AFTERNOON AND
EARLY EVENING...EXPECT THUNDERSTORM POTENTIAL TO SHIFT NORTH
OVERNIGHT...WHERE A FEW OF OUR COUNTIES ARE HIGHLIGHTED IN SLIGHT
RISK FOR SEVERE WEATHER FROM SPC.
OTHERWISE...EXPECT A FAIRLY NICE...BUT BREEZY DAY...ACROSS THE
REGION ON WEDNESDAY...AS SKIES WILL CLEAR BEHIND THE PASSING FRONT
AND TEMPERATURES WILL BE SIGNIFICANTLY COOLER THAN THIS AFTERNOONS
VALUES.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 350 PM CDT TUE JUN 11 2013
ALOFT: GLOBAL MODELS AND THEIR ENSEMBLES ARE IN EXCELLENT AGREEMENT
ON THE LONG-WAVE /LGWV/ FLOW THRU THE FCST PERIOD AND EVEN THRU DAY
10 /JUN 20TH/. THE GENERAL PATTERN WILL FEATURE A RIDGE OVER THE
PLAINS WITH TROFS ON BOTH COASTS. THE CLOSED LOW CURRENTLY MILLING
AROUND OFF BRITISH COLUMBIA WILL GET SLOWLY KICKED INTO THE PAC NW
WED-THU AND KNOCK DOWN THE RIDGE FRI-SAT BEFORE EMERGING INTO AND
DEEPENING THE ERN USA TROF. THIS WILL FORCE THE RIDGE TO RETROGRADE
INTO THE ROCKIES AS IT REBUILDS. THE INITIAL INDICATIONS ARE THAT
THE RIDGE WILL ADVANCE BACK INTO THE PLAINS THE MIDDLE OF NEXT WEEK
AS THE NEXT NE PAC LOW MOVES ONSHORE.
SFC: THE COOL FRONT MOVES THRU WED WILL SINK TO THE KS-OK BORDER BY
DAWN THU...WITH CANADIAN HIGH PRES BUILDING S INTO THE REGION. THE
ADVANCE OF THE UPR LOW AND THE PV ANOMALIES ORBITING IT WILL
INITIATE A NEW LEE LOW THU NGT...WITH THE FRONT LIFTING BACK N. THIS
WILL SPREAD THE 90+ HEAT BACK N INTO S-CNTRL NEB FRI. THE COOL FRONT
ASSOCIATED WITH THE ADVANCING PAC NW UPR LOW WILL ARRIVE HERE FRI
NGT AND WASH OUT. AS THE REMNANTS OF UPR LOW DROP INTO THE ERN USA
TROF EARLY NEXT WEEK...A MUCH STRONGER COOL FRONT WILL MOVE THRU SUN
NGT.
THE DAILY DETAILS...
THU: QUIET WITH TEMPS CLOSE TO NORMAL. COULD SEE AN EVNG SHWR/TSTM
DRIFT IN FROM NW KS OR WRN NEB.
THU NGT: COULD SEE AN MCS ROLL THRU HERE OR NEARBY AS LLJ PUNCHES
OVER THE LIFTING WARM FRONT.
FRI: HOT AND BREEZY IN THE WARM SECTOR. IF AN MCS OCCURS IT WILL
REINFORCE AND SLOW OR STALL THE WARM FRONT. TEMPS COULD BUST IF
COOL/CLOUDY CONDITIONS LINGER. THE WARM FRONT COULD ALSO BE A FOCUS
FOR RENEWED LATE DAY TSTM DEVELOPMENT.
FRI NGT: STRONG CONVERGENCE WITH PASSAGE OF COOL FRONT. THIS COULD
BE A DECENT OPPORTUNITY FOR TSTMS WHERE PARCELS CAN REACH THE LFC.
SAT-SUN: NEAR NORMAL TEMPS AND DRY MOST OF THE TIME. HOWEVER...
THERE WILL BE A RISK OF TSTMS EACH DAY...HIGHEST PROBABILITY BETWEEN
4PM-4AM. AT THIS POINT BELIEVE THE BEST CHANCE FOR ORGANIZED/
WIDESPREAD TSTMS WILL BE SUN AFTN-NGT.
MON: PROBABLY ENDS UP DRY AS AMPLIFYING ERN USA TROF WILL TAKE THE
COOL FRONT FARTHER S THAN ITS PREDECESSORS.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING)
ISSUED AT 550 PM CDT TUE JUN 11 2013
WIND WILL BE TRICKY FOR THIS FORECAST AS A NEARLY STATIONARY FRONT
LIES JUST TO THE SOUTH...AFFECTING WIND DIRECTION AND SPEED. BEST
GUESS WILL BE A DIRECTION FROM THE SOUTHEAST AS THE TERMINAL
SHOULD BE JUST NORTH OF THE BOUNDARY...WITH A DECREASE SHORTLY
INTO THE FORECAST. A COLD FRONT SHOULD CHANGE THE WIND DIRECTION
LATE TONIGHT TO THE NORTH NORTHWEST AFTER A COLD FRONT COMES
THROUGH AND AN INCREASE TO WIND SPEEDS...ESPECIALLY AS MIXING
INCREASES. VFR CONDITIONS ARE ANTICIPATED AND ONLY A SLIGHT CHANCE
OF THUNDERSTORMS EXISTS FOR TONIGHT. WITH SUCH A LOW
CHANCE...THUNDERSTORMS WERE LEFT OUT OF THE FORECAST.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...WIND ADVISORY UNTIL 8 PM CDT THIS EVENING FOR KSZ018-019.
&&
$$
SHORT TERM...SAR
LONG TERM...HALBLAUB
AVIATION...HEINLEIN
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
649 PM EDT MON JUN 10 2013
.SYNOPSIS...
LOW PRESSURE SYSTEM AND FRONT WILL MOVE ACROSS NEW YORK AND
PENNSYLVANIA TONIGHT AND TUESDAY BRINGING OCCASIONAL SHOWERS. A RUMBLE
OF THUNDER IS POSSIBLE THIS EVENING. WEDNESDAY WILL SEE SOMEWHAT OF A
BREAK IN THE WEATHER BEFORE THE NEXT SYSTEM MOVES IN THURSDAY. THE
CHANCE FOR RAIN THURSDAY WILL BE HIGHER ACROSS PENNSYLVANIA AND
LOWER ACROSS NEW YORK TOWARD THE LAKES.
&&
.NEAR TERM /THROUGH TUESDAY/...
630 PM EDT UPDATE...
MADE MINOR CHANGES TO THE FORECAST. INCREASED POPS IN THE WEST
PORTIONS OF THE CWA AS A BAND OF LIGHT RAIN SHOWERS IS MOVING IN
FROM CENTRAL PA. CURRENT ANALYSIS IS INDICATING THAT MID LVL
FRONTOGENSIS IS TAKING PLACE OVER CENTRAL NY...WHICH SHOULD SERVE AS
A FOCUSING MECHANISM FOR HEAVY RAINFALL THIS EVENING. WE`LL HAVE
TO MONITOR THE POTENTIAL FOR FLASH FLOODING OVER THE CATSKILLS
AND NE PA THIS EVENING...WHICH IS THE REGION OF THE HIGHEST PWAT
VALUES. OTHER THEN THAN...PREVIOUS FORECAST HOLDS GOOD.
230 PM UPDATE...
RAINFALL SO FAR TODAY HAS BEEN IN THE QUARTER TO LESS THAN HALF
INCH RAIN. MAYBE A FEW BREAKS HERE IN THE SHOWERS AND THEN HI RES
MODELS HAVE A GOOD BATCH OF PCPN MOVING THROUGH IN THE 00Z TO 03Z
TIME FRAME. HRRR IS A LITTLE SLOWER THAN THE ARW. ARW HAS BEEN
DOING WELL WITH ITS FCSTS. THIS EVENING SEEMS LIKE THE BEST
CHANCE FOR HEAVY RAIN AND ANY THUNDER. PRIMARY FOCUS AREA REMAINS
OVER NE PA AND THE CATSKILLS. LOCALIZED FLASH FLOODING WILL HAVE
TO BE MONITORED BUT OVER 2 INCHES IS NEEDED IN 3 HOURS WHICH WOULD
NEED A CLUSTER OF GOOD CONVECTION TO TRIGGER THIS AND THAT DOES
NOT SEEM LIKELY. TOWARD MORNING SCATTERED LIGHT SHOWERS OR
OCCASSIONAL OR EVEN DRIZZLE IS LIKELY.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/...
UPR LEVEL LOW MOVES ACROSS NY TUESDAY HELPING TRIGGER MORE
SHOWERS. TUESDAY NIGHT STILL HAVE CYCLONIC NW FLOW AND A FAVORABLE
JET REGION. SHORT WAVE RIDGE BUILDS IN WEDNESDAY AHEAD OF THE NEXT
SYSTEM. BEST CHANCE AT DRY WEATHER. WARM FRONT PUSHES IN THURSDAY
WITH A JET ENTRANCE REGION. MODELS HAVE BEEN TRENDING FURTHER N
EACH RUN WITH THE CLOUDS AND PCPN. MAIN FOCUS AND TRACK OF THE
CENTER REMAINS WELL TO OUR SOUTH THURSDAY BUT MODELS ARE SETTING
UP A BAND OF GOOD RAIN ACROSS PA NRN TIER AND SOME IN THE NY SRN
TIER.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
230 PM UPDATE...MED RNG FCST FOLLOWED CLOSELY THE WPC GUIDANCE FOR
THIS PD. CHCS FOR -SHRA ASSCD WITH LOW PRES DEPARTING THE MID
ALTC RGN ON THU NGT (MAINLY SRN NY AND NE PA)...THEN THE PSBLTY OF
SCT- SHRA ON FRI WITH PASSING S/WV`S IN NW FLOW. AFTER THAT...SFC
HI PRES IS XPCT TO BUILD INTO THE RGN FOR A NICE WEEKEND WITH
MAXES GNRLY IN THE L/M70S.
&&
.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
AS LOW PRES TRACKS FROM THE LOWER GTLAKES TWDS THE ST LAWRENCE
VLY LATER TNGT...WE XPCT WDSPRD IFR/MVFR THIS AFTN INTO THE OVRNGT
HRS DUE TO RAIN/DZ/CIGS AND VSBY`S...WITH SOME TERMINALS (SPCLY
ITH/BGM/ELM) SEEING CONDITIONS BLO ALT MINS AT TIMES. MAIN BATCH
OF RAIN IS XPCTD TO SLIDE OFF TO THE EAST LATER THIS EVNG...WITH
MORE SHRA LIKELY TMRW MRNG INTO EARLY AFTN WITH PSSG OF THE UPR
TROF AXIS. PLENTY OF LOW LVL MSTR AND XPCT IFR/MVFR TO LINGER INTO
TMRW MRNG AT MOST SITES.
WINDS THIS AFTN GNRLY FROM THE SE AT 10-15 KTS WITH G15-20 HIER
ELEVATIONS...BECMG SRLY LATER TNGT 5-10 KTS THEN WSW ON TUE 10-15KTS.
OUTLOOK...
TUE...IFR/MVFR WITH SHOWERS AND TSTMS.
WED THROUGH FRI...MAINLY VFR.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...BMW
NEAR TERM...BMW/KAH
SHORT TERM...BMW
LONG TERM...
AVIATION...
AREA FORECAST DISCUSSION
NWS BUFFALO NY
436 PM EDT MON JUN 10 2013
.SYNOPSIS...
LOW PRESSURE WILL MOVE ACROSS THE REGION TONIGHT...BRINGING WIDESPREAD
SHOWERS AND PERHAPS A FEW THUNDERSTORMS. THIS LOW WILL EXIT INTO NEW
ENGLAND ON TUESDAY...WITH A RETURN TO FAIR AND SEASONABLY WARM
WEATHER ON WEDNESDAY. MAINLY DRY AND SEASONABLE WEATHER SHOULD
PERSIST THROUGH THE END OF THE WEEK AS HIGH PRESSURE BUILDS SOUTH
FROM CENTRAL CANADA.
&&
.NEAR TERM /THROUGH TUESDAY/...
FOR THE REMAINDER OF TODAY...STEADY SHOWERS WILL LIFT ACROSS LAKE
ONTARIO AND ACROSS THE EASTERN LAKE ONTARIO REGION. THIS AREA
APPEARS TO BE LINED UP WITH AN AREA OF WARM AIR ADVECTION IN THE
MID-LEVELS...WITH A GENERAL NORTHWARD PROGRESSION LIKELY GIVEN THE
FLOW ALOFT AND NAM/RGEM/GFS MODEL GUIDANCE. NOTED THE HRRR HAS NOT
CAPTURED THIS AREA WELL...AND THUS CANNOT BE USED TO FORECAST THIS
FEATURE.
IN ADDITION...THERE IS ANOTHER AREA OF SHOWERS WITH SOME EMBEDDED
THUNDERSTORMS DEVELOPING ACROSS NORTHERN OHIO AND WESTERN
PENNSYLVANIA. THIS AREA ROUGHLY LINES UP WITH THE LEADING EDGE OF
AN UPPER LEVEL TROF...WITH THE HRRR SHOWING SOME SKILL IN CAPTURING
THIS SHOWER DEVELOPMENT. GIVEN THE SLOW EASTWARD PROGRESSION OF THE
UPPER LOW...EXPECT THIS TO DRIFT INTO WESTERN PORTIONS OF THE
SOUTHERN TIER EARLY EVENING...WITH SHOWERS SPREADING NORTH AND EAST
OVERNIGHT. THIS IS ALSO IN LINE WITH NAM/SREF/RGEM GUIDANCE...WHICH
ALSO SHOWS SOME ENHANCEMENT ACROSS NW PORTIONS OF THE NIAGARA
FRONTIER WHERE THE LOW WILL ENHANCED SURFACE CONVERGENCE. ALL THIS
SUGGESTS THAT WHILE MANY MAY GET A BREAK FROM THE RAIN LATE THIS
AFTERNOON...MORE IS ON THE WAY.
THUS FAR UPSTREAM LIGHTNING ACTIVITY IS QUITE LIMITED...AND IT NOW
APPEARS THE BEST CHANCE FOR ANY THUNDERSTORMS WILL BE THIS EVENING
AS THE LOW AND UPPER LOW MOVE ACROSS THE REGION. MEAN QPFS
CONTINUE TO RUN IN THE .50 TO 1.00 INCH RANGE THROUGH TONIGHT...WITH
THE GREATEST AMOUNTS LIKELY TO BE EAST OF LAKE ONTARIO...AND
ACROSS NW PORTIONS OF NIAGARA FRONTIER. WITH PRECIPITABLE WATER
VALUES BETWEEN 1.50 AND 1.75 INCHES...LOCALLY HIGHER AMOUNTS ARE
POSSIBLE...BUT GIVEN THE TIME BETWEEN WAVES IT WOULD LIKELY TAKE
SLOW MOVING OR TRAINING CONVECTION TO CAUSE ANY FLOODING. THIS
POTENTIAL APPEARS TO BE LIMITED.
OTHERWISE...TEMPERATURES WILL DROP VERY LITTLE OVERNIGHT...WITH LOWS
ONLY IN THE LOWER TO MID 60S. PATCHY FOG MAY DEVELOP AS THE SURFACE
LOW CROSSES THE LAKES THIS EVENING.
ON TUESDAY...THE OPENING 500 MB TROF AXIS WILL BE ACROSS EASTERN
PORTIONS OF THE CWA...WITH IT FORECAST TO CONTINUE TO SLOWLY TRACK
EASTWARD DURING THE DAY. THIS WILL RESULT IN LINGERING SHOWER
ACTIVITY DURING THE DAY...WITH THE MOST WIDESPREAD ACTIVITY ACROSS
EASTERN PORTIONS. EXPECT CLOUDS TO LINGER MOST OF THE DAY...LIMITING
HIGHS TO THE MID AND UPPER 60S...AND PERHAPS 70 ACROSS THE NIAGARA
FRONTIER.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY NIGHT/...
TUESDAY NIGHT A WEAK MID LEVEL CLOSED LOW WILL FORM OVER SOUTHEAST
QUEBEC AND SLOWLY DRIFT ACROSS NORTHERN NEW ENGLAND ON WEDNESDAY. AT
THE SURFACE AN ASSOCIATED WEAK LOW WILL TAKE A SIMILAR...ALBEIT
SLIGHTLY FARTHER SOUTH TRACK FROM NORTHEAST NY TUESDAY EVENING TO
THE GULF OF MAINE BY WEDNESDAY. THIS SYSTEM WILL MAINTAIN MOIST
CYCLONIC FLOW ACROSS THE NORTH COUNTRY TUESDAY NIGHT THROUGH
WEDNESDAY MORNING WITH A FEW LINGERING SHOWERS AND CLOUDS...
ESPECIALLY ACROSS THE HIGHER TERRAIN WITH AN ADDED BOOST FROM
UPSLOPE FLOW. A FEW SHOWERS MAY ALSO LINGER TUESDAY EVENING ACROSS
MUCH OF CENTRAL AND WESTERN NY MAINLY INLAND FROM THE LAKES WITH
LINGERING LOW LEVEL MOISTURE AND WEAK INSTABILITY. THESE SHOWERS
FARTHER WEST WILL QUICKLY DIMINISH LATER TUESDAY EVENING WITH THE
LOSS OF DAYTIME HEATING.
LATER WEDNESDAY THE CLOSED LOW WILL PULL AWAY FROM NEW ENGLAND WITH
DEEPER MOISTURE SLOWLY DIMINISHING ACROSS THE NORTH COUNTRY. THIS
SHOULD ALLOW ANY LINGERING SHOWERS TO END...ALTHOUGH A GOOD AMOUNT
OF CLOUD COVER WILL LINGER. FARTHER WEST...12Z MODEL GUIDANCE
REMAINS CONSISTENT IN DEVELOPING A CORRIDOR OF CONVECTION FROM THE
MIDWEST INTO OHIO AND PA BY THE END OF THE DAY. THIS SHOULD REMAIN
SAFELY TO OUR SOUTHWEST...LEAVING MUCH OF THE CWA IN A WEAK SURFACE
RIDGE BETWEEN THE TWO SYSTEMS. THIS SHOULD ALLOW FOR AT LEAST SOME
PARTIAL SUNSHINE WITH TEMPERATURES VERY CLOSE TO AVERAGE.
WEDNESDAY NIGHT INTO THURSDAY MEDIUM RANGE GUIDANCE TAKES A SERIES
OF MID LEVEL SHORTWAVES AND ASSOCIATED COMPLEXES OF SHOWERS AND
THUNDERSTORMS ACROSS THE UPPER MIDWEST AND OHIO VALLEY...THE
STRONGEST OF WHICH APPEARS TO BE LATE WEDNESDAY NIGHT AND THURSDAY.
THIS PARTICULAR SYSTEM CAN BE TRACED TO A VIGOROUS CLOSED LOW OVER
CALIFORNIA AND NEVADA THIS AFTERNOON. THIS SYSTEM WILL CREST OVER
THE TOP OF THE SOUTH CENTRAL CONUS RIDGE AND FORCE CONVECTION ALONG
A BAROCLINIC ZONE OVER THE UPPER MIDWEST. THE NAM REMAINS OUT OF
SYNC WITH THE REST OF THE MODEL GUIDANCE IN TAKING THIS SYSTEM MUCH
FARTHER NORTH ON THURSDAY AND WILL BE DISCOUNTED.
FOLLOWING THE CONSENSUS OF THE GFS/GEM/ECMWF...THE LAST STRONGEST
SYSTEM LATE WEDNESDAY NIGHT AND THURSDAY MAY PASS CLOSE ENOUGH
THROUGH OHIO AND PA TO BRING A CHANCE OF SHOWERS AND THUNDERSTORMS
TO THE WESTERN SOUTHERN TIER...BUT STILL EXPECT THE BULK OF IT TO
STAY SOUTH OF THE AREA AND CLOSER TO MORE ROBUST INSTABILITY OVER
THE OHIO VALLEY. OTHERWISE FOR THE REST OF THE AREA EXPECT AT LEAST
PARTIAL SUNSHINE DURING THE DAY THURSDAY WITH TEMPERATURES JUST
SLIGHTLY COOLER THAN WEDNESDAY AS NORTHERLY FLOW INCREASES ON THE
NORTHERN PERIPHERY OF THE LOW PASSING THROUGH PA.
THURSDAY NIGHT THE MID LEVEL SHORTWAVE AND ASSOCIATED SURFACE LOW
WILL RACE OFF THE EAST COAST WITH ANY SHOWER CHANCE ACROSS THE
SOUTHERN TIER ENDING. NORTHERLY FLOW WILL TAKE HOLD AS A NORTHERN
STREAM TROUGH BEGINS TO AMPLIFY WITH THE FIRST SHORTWAVE...WHICH
WILL DRAG A COOLER AND DRIER AIRMASS INTO THE GREAT LAKES AND
NORTHEAST.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
A PERIOD OF DRIER WEATHER WILL FINALLY MAKE AN APPEARANCE FOR MUCH
OF THE LONG TERM...ALTHOUGH THERE ARE A FEW WEAK SYSTEMS OF
INTEREST. THE GENERAL PATTERN WILL FEATURE AN AMPLIFYING TROUGH
ACROSS NORTHERN NEW ENGLAND AND THE CANADIAN MARITIMES OVER THE
WEEKEND...WHICH WILL MAINTAIN NORTHWEST FLOW ACROSS THE GREAT LAKES
REGION. THE ECMWF IS MORE AMPLIFIED WITH THIS PATTERN THAN THE
GFS...WHICH WOULD KEEP THE WEEKEND A LITTLE COOLER. THE TROUGH WILL
BE FAR ENOUGH EAST TO KEEP OUR REGION IN A GENERALLY DRY CONFLUENT
NORTHWEST FLOW WITH HIGH PRESSURE BUILDING IN AT THE SURFACE.
A NORTHERN STREAM SHORTWAVE WILL DIG SOUTH ACROSS THE AREA ON FRIDAY
ON THE LEADING EDGE OF THE TROUGH. THE MORE AMPLIFIED ECMWF REMAINS
MORE AGGRESSIVE WITH THIS FEATURE AND DEVELOPS SHOWERS ACROSS THE
AREA ON FRIDAY AIDED BY DAYTIME HEATING. FOR NOW WILL FAVOR THE LESS
AMPLIFIED GFS SOLUTION AND KEEP FRIDAY MAINLY DRY WITH JUST AN
INCREASE IN CLOUDS WITH THE TROUGH PASSAGE.
OVER THE WEEKEND SURFACE HIGH PRESSURE WILL BUILD OVER THE GREAT
LAKES. THIS SHOULD KEEP BOTH DAYS DRY WITH SEASONABLE TEMPERATURES.
IF THE LESS AMPLIFIED GFS VERIFIES TEMPS MAY CREEP A LITTLE ABOVE
AVERAGE.
BY SUNDAY NIGHT AND MONDAY BOTH THE GFS AND ECMWF BRING THE NEXT
TROUGH INTO THE GREAT LAKES. SOUTHWEST RETURN FLOW WILL INCREASE
AHEAD OF THIS SYSTEM AND BRING INCREASING MOISTURE ALONG WITH
INCREASING CHANCES OF SHOWERS AND THUNDERSTORMS.
&&
.AVIATION /21Z MONDAY THROUGH SATURDAY/...
LOW PRESSURE WILL LIFT FROM THE OHIO VALLEY AND ACROSS LAKE
ERIE/ONTARIO TONIGHT. AHEAD OF THIS...EXPECT MIXED CONDITIONS IN
AND OUT OF SHOWERS...WITH PREDOMINANTLY VFR/MVFR CONDITIONS AT MOST
TAF LOCATIONS. STEADIER RAINS WILL MOVE IN AHEAD OF AND WITH THE LOW
THIS EVENING...WITH CIGS EXPECTED TO DROP SIGNIFICANTLY WITH THE WIND SHIFT
AS THE LOW PASSES THROUGH. IFR CONDITIONS ARE LIKELY LATE TONIGHT IN
LOW CIGS...AND LINGERING RAIN SHOWERS. THERE IS A SLIGHT CHANCE OF A
THUNDERSTORM THIS EVENING...WITH WIDESPREAD LIGHTNING UNLIKELY.
ON TUESDAY...EXPECT IFR CONDITIONS TO GRADUALLY IMPROVE TO MVFR/VFR
AS DRIER AIR BUILDS IN. THIS MAY TAKE MOST OF THE DAY...WITH THE
UPPER TROF SLOWLY EXITING EAST OF THE REGION DURING THE AFTERNOON
HOURS
OUTLOOK...
TUESDAY NIGHT...MAINLY MVFR. A CHANCE OF SHOWERS EAST...WITH
LINGERING LOW CLOUDS.
WEDNESDAY...MVFR IMPROVING TO VFR.
THURSDAY THROUGH SATURDAY...MAINLY VFR.
&&
.MARINE...
EASTERLY WINDS WILL INCREASE EARLY THIS EVENING AHEAD OF AN AREA OF
LOW PRESSURE PUSHING INTO THE OHIO VALLEY. THIS WILL PRODUCE SOME
CHOPPY WAVE CONDITIONS ON WESTERN LAKE ONTARIO HOWEVER THESE WILL
LIKELY REMAIN BELOW SMALL CRAFT ADVISORY CRITERIA. THIS LOW WILL
PASS JUST NORTH OF THE REGION TUESDAY AND COULD POSSIBLY PRODUCE A
BRIEF PERIOD OF SMALL CRAFT CONDITIONS ON LAKE ERIE AS WINDS FUNNEL
DOWN THE LAKE.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...APFFEL
NEAR TERM...APFFEL
SHORT TERM...HITCHCOCK
LONG TERM...HITCHCOCK
AVIATION...APFFEL
MARINE...APFFEL/HITCHCOCK
AREA FORECAST DISCUSSION
NWS BUFFALO NY
341 PM EDT MON JUN 10 2013
.SYNOPSIS...
LOW PRESSURE WILL MOVE ACROSS THE REGION TONIGHT...BRINGING WIDESPREAD
SHOWERS AND PERHAPS A FEW THUNDERSTORMS. THIS LOW WILL EXIT INTO NEW
ENGLAND ON TUESDAY...WITH A RETURN TO FAIR AND SEASONABLY WARM
WEATHER ON WEDNESDAY. MAINLY DRY AND SEASONABLE WEATHER SHOULD
PERSIST THROUGH THE END OF THE WEEK AS HIGH PRESSURE BUILDS RIDGES
IN FROM CENTRAL CANADA.
&&
.NEAR TERM /THROUGH TUESDAY/...
FOR THE REMAINDER OF TODAY...STEADY SHOWERS WILL LIFT ACROSS LAKE
ONTARIO AND ACROSS THE EASTERN LAKE ONTARIO REGION. THIS AREA
APPEARS TO BE LINED UP WITH AN AREA OF WARM AIR ADVECTION IN THE
MID-LEVELS...WITH A GENERAL NORTHWARD PROGRESSION LIKELY GIVEN THE
FLOW ALOFT AND NAM/RGEM/GFS MODEL GUIDANCE. NOTED THE HRRR HAS NOT
CAPTURED THIS AREA WELL...AND THUS CANNOT BE USED TO FORECAST THIS
FEATURE.
IN ADDITION...THERE IS ANOTHER AREA OF SHOWERS WITH SOME EMBEDDED
THUNDERSTORMS DEVELOPING ACROSS NORTHERN OHIO AND WESTERN
PENNSYLVANIA. THIS AREA ROUGHLY LINES UP WITH THE LEADING EDGE OF
AN UPPER LEVEL TROF...WITH THE HRRR SHOWING SOME SKILL IN CAPTURING
THIS SHOWER DEVELOPMENT. GIVEN THE SLOW EASTWARD PROGRESSION OF THE
UPPER LOW...EXPECT THIS TO DRIFT INTO WESTERN PORTIONS OF THE
SOUTHERN TIER EARLY EVENING...WITH SHOWERS SPREADING NORTH AND EAST
OVERNIGHT. THIS IS ALSO IN LINE WITH NAM/SREF/RGEM GUIDANCE...WHICH
ALSO SHOWS SOME ENHANCEMENT ACROSS NW PORTIONS OF THE NIAGARA
FRONTIER WHERE THE LOW WILL ENHANCED SURFACE CONVERGENCE. ALL THIS
SUGGESTS THAT WHILE MANY MAY GET A BREAK FROM THE RAIN LATE THIS
AFTERNOON...MORE IS ON THE WAY.
THUS FAR UPSTREAM LIGHTNING ACTIVITY IS QUITE LIMITED...AND IT NOW
APPEARS THE BEST CHANCE FOR ANY THUNDERSTORMS WILL BE THIS EVENING
AS THE LOW AND UPPER LOW MOVE ACROSS THE REGION. MEAN QPFS
CONTINUE TO RUN IN THE .50 TO 1.00 INCH RANGE THROUGH TONIGHT...WITH
THE GREATEST AMOUNTS LIKELY TO BE EAST OF LAKE ONTARIO...AND
ACROSS NW PORTIONS OF NIAGARA FRONTIER. WITH PRECIPITABLE WATER
VALUES BETWEEN 1.50 AND 1.75 INCHES...LOCALLY HIGHER AMOUNTS ARE
POSSIBLE...BUT GIVEN THE TIME BETWEEN WAVES IT WOULD LIKELY TAKE
SLOW MOVING OR TRAINING CONVECTION TO CAUSE ANY FLOODING. THIS
POTENTIAL APPEARS TO BE LIMITED.
OTHERWISE...TEMPERATURES WILL DROP VERY LITTLE OVERNIGHT...WITH LOWS
ONLY IN THE LOWER TO MID 60S. PATCHY FOG MAY DEVELOP AS THE SURFACE
LOW CROSSES THE LAKES THIS EVENING.
ON TUESDAY...THE OPENING 500 MB TROF AXIS WILL BE ACROSS EASTERN
PORTIONS OF THE CWA...WITH IT FORECAST TO CONTINUE TO SLOWLY TRACK
EASTWARD DURING THE DAY. THIS WILL RESULT IN LINGERING SHOWER
ACTIVITY DURING THE DAY...WITH THE MOST WIDESPREAD ACTIVITY ACROSS
EASTERN PORTIONS. EXPECT CLOUDS TO LINGER MOST OF THE DAY...LIMITING
HIGHS TO THE MID AND UPPER 60S...AND PERHAPS 70 ACROSS THE NIAGARA
FRONTIER.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY NIGHT/...
TUESDAY NIGHT A WEAK MID LEVEL CLOSED LOW WILL FORM OVER SOUTHEAST
QUEBEC AND SLOWLY DRIFT ACROSS NORTHERN NEW ENGLAND ON WEDNESDAY. AT
THE SURFACE AN ASSOCIATED WEAK LOW WILL TAKE A SIMILAR...ALBEIT
SLIGHTLY FARTHER SOUTH TRACK FROM NORTHEAST NY TUESDAY EVENING TO
THE GULF OF MAINE BY WEDNESDAY. THIS SYSTEM WILL MAINTAIN MOIST
CYCLONIC FLOW ACROSS THE NORTH COUNTRY TUESDAY NIGHT THROUGH
WEDNESDAY MORNING WITH A FEW LINGERING SHOWERS AND CLOUDS...
ESPECIALLY ACROSS THE HIGHER TERRAIN WITH AN ADDED BOOST FROM
UPSLOPE FLOW. A FEW SHOWERS MAY ALSO LINGER TUESDAY EVENING ACROSS
MUCH OF CENTRAL AND WESTERN NY MAINLY INLAND FROM THE LAKES WITH
LINGERING LOW LEVEL MOISTURE AND WEAK INSTABILITY. THESE SHOWERS
FARTHER WEST WILL QUICKLY DIMINISH LATER TUESDAY EVENING WITH THE
LOSS OF DAYTIME HEATING.
LATER WEDNESDAY THE CLOSED LOW WILL PULL AWAY FROM NEW ENGLAND WITH
DEEPER MOISTURE SLOWLY DIMINISHING ACROSS THE NORTH COUNTRY. THIS
SHOULD ALLOW ANY LINGERING SHOWERS TO END...ALTHOUGH A GOOD AMOUNT
OF CLOUD COVER WILL LINGER. FARTHER WEST...12Z MODEL GUIDANCE
REMAINS CONSISTENT IN DEVELOPING A CORRIDOR OF CONVECTION FROM THE
MIDWEST INTO OHIO AND PA BY THE END OF THE DAY. THIS SHOULD REMAIN
SAFELY TO OUR SOUTHWEST...LEAVING MUCH OF THE CWA IN A WEAK SURFACE
RIDGE BETWEEN THE TWO SYSTEMS. THIS SHOULD ALLOW FOR AT LEAST SOME
PARTIAL SUNSHINE WITH TEMPERATURES VERY CLOSE TO AVERAGE.
WEDNESDAY NIGHT INTO THURSDAY MEDIUM RANGE GUIDANCE TAKES A SERIES
OF MID LEVEL SHORTWAVES AND ASSOCIATED COMPLEXES OF SHOWERS AND
THUNDERSTORMS ACROSS THE UPPER MIDWEST AND OHIO VALLEY...THE
STRONGEST OF WHICH APPEARS TO BE LATE WEDNESDAY NIGHT AND THURSDAY.
THIS PARTICULAR SYSTEM CAN BE TRACED TO A VIGOROUS CLOSED LOW OVER
CALIFORNIA AND NEVADA THIS AFTERNOON. THIS SYSTEM WILL CREST OVER
THE TOP OF THE SOUTH CENTRAL CONUS RIDGE AND FORCE CONVECTION ALONG
A BAROCLINIC ZONE OVER THE UPPER MIDWEST. THE NAM REMAINS OUT OF
SYNC WITH THE REST OF THE MODEL GUIDANCE IN TAKING THIS SYSTEM MUCH
FARTHER NORTH ON THURSDAY AND WILL BE DISCOUNTED.
FOLLOWING THE CONSENSUS OF THE GFS/GEM/ECMWF...THE LAST STRONGEST
SYSTEM LATE WEDNESDAY NIGHT AND THURSDAY MAY PASS CLOSE ENOUGH
THROUGH OHIO AND PA TO BRING A CHANCE OF SHOWERS AND THUNDERSTORMS
TO THE WESTERN SOUTHERN TIER...BUT STILL EXPECT THE BULK OF IT TO
STAY SOUTH OF THE AREA AND CLOSER TO MORE ROBUST INSTABILITY OVER
THE OHIO VALLEY. OTHERWISE FOR THE REST OF THE AREA EXPECT AT LEAST
PARTIAL SUNSHINE DURING THE DAY THURSDAY WITH TEMPERATURES JUST
SLIGHTLY COOLER THAN WEDNESDAY AS NORTHERLY FLOW INCREASES ON THE
NORTHERN PERIPHERY OF THE LOW PASSING THROUGH PA.
THURSDAY NIGHT THE MID LEVEL SHORTWAVE AND ASSOCIATED SURFACE LOW
WILL RACE OFF THE EAST COAST WITH ANY SHOWER CHANCE ACROSS THE
SOUTHERN TIER ENDING. NORTHERLY FLOW WILL TAKE HOLD AS A NORTHERN
STREAM TROUGH BEGINS TO AMPLIFY WITH THE FIRST SHORTWAVE...WHICH
WILL DRAG A COOLER AND DRIER AIRMASS INTO THE GREAT LAKES AND
NORTHEAST.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
A PERIOD OF DRIER WEATHER WILL FINALLY MAKE AN APPEARANCE FOR MUCH
OF THE LONG TERM...ALTHOUGH THERE ARE A FEW WEAK SYSTEMS OF
INTEREST. THE GENERAL PATTERN WILL FEATURE AN AMPLIFYING TROUGH
ACROSS NORTHERN NEW ENGLAND AND THE CANADIAN MARITIMES OVER THE
WEEKEND...WHICH WILL MAINTAIN NORTHWEST FLOW ACROSS THE GREAT LAKES
REGION. THE ECMWF IS MORE AMPLIFIED WITH THIS PATTERN THAN THE
GFS...WHICH WOULD KEEP THE WEEKEND A LITTLE COOLER. THE TROUGH WILL
BE FAR ENOUGH EAST TO KEEP OUR REGION IN A GENERALLY DRY CONFLUENT
NORTHWEST FLOW WITH HIGH PRESSURE BUILDING IN AT THE SURFACE.
A NORTHERN STREAM SHORTWAVE WILL DIG SOUTH ACROSS THE AREA ON FRIDAY
ON THE LEADING EDGE OF THE TROUGH. THE MORE AMPLIFIED ECMWF REMAINS
MORE AGGRESSIVE WITH THIS FEATURE AND DEVELOPS SHOWERS ACROSS THE
AREA ON FRIDAY AIDED BY DAYTIME HEATING. FOR NOW WILL FAVOR THE LESS
AMPLIFIED GFS SOLUTION AND KEEP FRIDAY MAINLY DRY WITH JUST AN
INCREASE IN CLOUDS WITH THE TROUGH PASSAGE.
OVER THE WEEKEND SURFACE HIGH PRESSURE WILL BUILD OVER THE GREAT
LAKES. THIS SHOULD KEEP BOTH DAYS DRY WITH SEASONABLE TEMPERATURES.
IF THE LESS AMPLIFIED GFS VERIFIES TEMPS MAY CREEP A LITTLE ABOVE
AVERAGE.
BY SUNDAY NIGHT AND MONDAY BOTH THE GFS AND ECMWF BRING THE NEXT
TROUGH INTO THE GREAT LAKES. SOUTHWEST RETURN FLOW WILL INCREASE
AHEAD OF THIS SYSTEM AND BRING INCREASING MOISTURE ALONG WITH
INCREASING CHANCES OF SHOWERS AND THUNDERSTORMS.
&&
.AVIATION /20Z MONDAY THROUGH SATURDAY/...
LOW PRESSURE WILL LIFT FROM THE OHIO VALLEY AND ACROSS LAKE
ERIE/ONTARIO TONIGHT. AHEAD OF THIS...EXPECT MIXED CONDITIONS IN
AND OUT OF SHOWERS...WITH PREDOMINANTLY VFR/MVFR CONDITIONS AT MOST
TAF LOCATIONS. STEADIER RAINS WILL MOVE IN AHEAD OF AND WITH THE LOW
THIS EVENING...WITH CIGS EXPECTED TO DROP SIGNIFICANTLY WITH THE WIND SHIFT
AS THE LOW PASSES THROUGH. IFR CONDITIONS ARE LIKELY LATE TONIGHT IN
LOW CIGS...AND LINGERING RAIN SHOWERS. THERE IS A SLIGHT CHANCE OF A
THUNDERSTORM THIS EVENING...WITH WIDESPREAD LIGHTNING UNLIKELY.
ON TUESDAY...EXPECT IFR CONDITIONS TO GRADUALLY IMPROVE TO MVFR/VFR
AS DRIER AIR BUILDS IN. THIS MAY TAKE MOST OF THE DAY...WITH THE
UPPER TROF SLOWLY EXITING EAST OF THE REGION DURING THE AFTERNOON
HOURS
OUTLOOK...
TUESDAY NIGHT...MAINLY MVFR. A CHANCE OF SHOWERS EAST...WITH
LINGERING LOW CLOUDS.
WEDNESDAY...MVFR IMPROVING TO VFR.
THURSDAY THROUGH SATURDAY...MAINLY VFR.
&&
.MARINE...
EASTERLY WINDS WILL INCREASE EARLY THIS EVENING AHEAD OF AN AREA OF
LOW PRESSURE PUSHING INTO THE OHIO VALLEY. THIS WILL PRODUCE SOME
CHOPPY WAVE CONDITIONS ON WESTERN LAKE ONTARIO HOWEVER THESE WILL
LIKELY REMAIN BELOW SMALL CRAFT ADVISORY CRITERIA. THIS LOW WILL
PASS JUST NORTH OF THE REGION TUESDAY AND COULD POSSIBLY PRODUCE A
BRIEF PERIOD OF SMALL CRAFT CONDITIONS ON LAKE ERIE AS WINDS FUNNEL
DOWN THE LAKE.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...APFFEL
NEAR TERM...APFFEL
SHORT TERM...HITCHCOCK
LONG TERM...HITCHCOCK
AVIATION...APFFEL
MARINE...APFFEL/HITCHCOCK
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
237 PM EDT MON JUN 10 2013
.SYNOPSIS...
LOW PRESSURE SYSTEM AND FRONT WILL MOVE ACROSS NEW YORK AND
PENNSYLVANIA TONIGHT AND TUESDAY BRINGING OCCASSIONAL SHOWERS. A RUMBLE
OF THUNDER IS POSSIBLE THIS EVENING. WEDNESDAY WILL SEE SOMEWHAT OF A
BREAK IN THE WEATHER BEFORE THE NEXT SYSTEM MOVES IN THURSDAY. THE
CHANCE FOR RAIN THURSDAY WILL BE HIGHER ACROSS PENNSYLVANIA AND
LOWER ACROSS NEW YORK TOWARD THE LAKES.
&&
.NEAR TERM /THROUGH TONIGHT/...
230 PM UPDATE...
RAINFALL SO FAR TODAY HAS BEEN IN THE QUARTER TO LESS THAN HALF
INCH RAIN. MAYBE A FEW BREAKS HERE IN THE SHOWERS AND THEN HI RES
MODELS HAVE A GOOD BATCH OF PCPN MOVING THROUGH IN THE 00Z TO 03Z
TIME FRAME. HRRR IS A LITTLE SLOWER THAN THE ARW. ARW HAS BEEN
DOING WELL WITH ITS FCSTS. THIS EVENING SEEMS LIKE THE BEST
CHANCE FOR HEAVY RAIN AND ANY THUNDER. PRIMARY FOCUS AREA REMAINS
OVER NE PA AND THE CATSKILLS. LOCALIZED FLASH FLOODING WILL HAVE
TO BE MONITORED BUT OVER 2 INCHES IS NEEDED IN 3 HOURS WHICH WOULD
NEED A CLUSTER OF GOOD CONVECTION TO TRIGGER THIS AND THAT DOES
NOT SEEM LIKELY. TOWARD MORNING SCATTERED LIGHT SHOWERS OR
OCCASSIONAL OR EVEN DRIZZLE IS LIKELY.
&&
.SHORT TERM /TUESDAY THROUGH THURSDAY/...
UPR LEVEL LOW MOVES ACROSS NY TUESDAY HELPING TRIGGER MORE
SHOWERS. TUESDAY NIGHT STILL HAVE CYCLONIC NW FLOW AND A FAVORABLE
JET REGION. SHORT WAVE RIDGE BUILDS IN WEDNESDAY AHEAD OF THE NEXT
SYSTEM. BEST CHANCE AT DRY WEATHER. WARM FRONT PUSHES IN THURSDAY
WITH A JET ENTRANCE REGION. MODELS HAVE BEEN TRENDING FURTHER N
EACH RUN WITH THE CLOUDS AND PCPN. MAIN FOCUS AND TRACK OF THE
CENTER REMAINS WELL TO OUR SOUTH THURSDAY BUT MODELS ARE SETTING
UP A BAND OF GOOD RAIN ACROSS PA NRN TIER AND SOME IN THE NY SRN
TIER.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
230 PM UPDATE...MED RNG FCST FOLLOWED CLOSELY THE WPC GUIDANCE FOR
THIS PD. CHCS FOR -SHRA ASSCD WITH LOW PRES DEPARTING THE MID
ALTC RGN ON THU NGT (MAINLY SRN NY AND NE PA)...THEN THE PSBLTY OF
SCT- SHRA ON FRI WITH PASSING S/WV`S IN NW FLOW. AFTER THAT...SFC
HI PRES IS XPCT TO BUILD INTO THE RGN FOR A NICE WEEKEND WITH
MAXES GNRLY IN THE L/M70S.
&&
.AVIATION /18Z MONDAY THROUGH SATURDAY/...
AS LOW PRES TRACKS FROM THE LOWER GTLAKES TWDS THE ST LAWRENCE
VLY LATER TNGT...WE XPCT WDSPRD IFR/MVFR THIS AFTN INTO THE OVRNGT
HRS DUE TO RAIN/DZ/CIGS AND VSBY`S...WITH SOME TERMINALS (SPCLY
ITH/BGM/ELM) SEEING CONDITIONS BLO ALT MINS AT TIMES. MAIN BATCH
OF RAIN IS XPCTD TO SLIDE OFF TO THE EAST LATER THIS EVNG...WITH
MORE SHRA LIKELY TMRW MRNG INTO EARLY AFTN WITH PSSG OF THE UPR
TROF AXIS. PLENTY OF LOW LVL MSTR AND XPCT IFR/MVFR TO LINGER INTO
TMRW MRNG AT MOST SITES.
WINDS THIS AFTN GNRLY FROM THE SE AT 10-15 KTS WITH G15-20 HIER
ELEVATIONS...BECMG SRLY LATER TNGT 5-10 KTS THEN WSW ON TUE 10-15KTS.
OUTLOOK...
TUE...IFR/MVFR WITH SHOWERS AND TSTMS.
WED THROUGH FRI...MAINLY VFR.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...BMW
NEAR TERM...BMW
SHORT TERM...BMW
LONG TERM...
AVIATION...
AREA FORECAST DISCUSSION
NWS BUFFALO NY
221 PM EDT MON JUN 10 2013
.SYNOPSIS...
WEAK HIGH PRESSURE WILL DRIFT AWAY FROM THE REGION ALLOWING AN
AREA OF LOW PRESSURE TO MOVE IN FROM THE OHIO VALLEY. THIS LOW
WILL SLOWLY CROSS THE REGION TODAY AND TUESDAY WITH WIDESPREAD
RAIN AND PERHAPS A FEW THUNDERSTORMS. DRY WEATHER WILL RETURN
WEDNESDAY AND SHOULD CONTINUE THROUGH THE REST OF THE WEEK AS HIGH
PRESSURE BUILDS INTO THE GREAT LAKES.
&&
.NEAR TERM /THROUGH TONIGHT/...
THROUGH EARLY AFTERNOON...RADAR SHOWS SHOWERS ACROSS THE
REGION...WITH THE STEADIEST ACTIVITY AT 200 PM EXTENDING BETWEEN
I-90 AND THE SOUTH SHORES OF LAKE ONTARIO...WITH ANOTHER STEADY
W-E BAND NORTH OF LAKE ONTARIO. THESE AREAS BOTH APPEAR TO BE
ALIGNED WITH TWO WAVES OF WARM AIR ADVECTION IN THE MID-LEVELS.
MODEL GUIDANCE HAS STRUGGLED TO RESOLVE THIS...WITH MUCH OF THE
GUIDANCE MERGING THESE TWO WAVES...UNABLE TO RESOLVE THE BREAKS.
MEANWHILE...THE HRRR HAS UNDERDONE THE RAIN ALONG THIS BOUNDARY.
DESPITE THE MIXED MODEL PERFORMANCE...TRENDS CONSISTENTLY LIFT
BOTH AREAS OF STEADIER RAIN SHOWERS GRADUALLY TO THE NORTH THROUGH
THE AFTERNOON HOURS. BEHIND THIS...IS MORE SCATTERED SHOWER
ACTIVITY ACROSS WESTERN PENNSYLVANIA. GIVEN SUPPORT FROM THE
NAM/SREF/RGEM...SUSPECT THE HRRR FORECAST OF EXPANDING THIS AND
MOVING IT INTO FAR WESTERN NEW YORK THIS EVENING WILL BE
CORRECT...BRINGING A RETURN TO STEADIER RAINS.
MEANWHILE THE SURFACE LOW IS FORECAST TO LIFT ACROSS THE LOWER
LAKES FROM LAKE ERIE THIS EVENING TO LAKE ONTARIO OVERNIGHT.
SUSPECT THIS WILL BRING YET ANOTHER ROUND OF PRECIPITATION...AS
THE ASSOCIATED UPPER TROF MOVES ACROSS WITH THE SURFACE LOW...AND
WITH ENHANCED CONVERGENCE WITH THE SURFACE LOW AND ITS ASSOCIATED
WIND FIELD.
THUS FAR UPSTREAM LIGHTNING ACTIVITY IS QUITE LIMITED...AND IT NOW
APPEARS THE BEST CHANCE FOR ANY THUNDERSTORMS WILL BE THIS EVENING
AS THE LOW AND UPPER LOW MOVE ACROSS THE REGION. MEAN QPFS
CONTINUE TO RUN IN THE .50 TO 1.00 INCH RANGE THROUGH TONIGHT...WITH
THE GREATEST AMOUNTS LIKELY TO BE EAST OF LAKE ONTARIO...AND
ACROSS NW PORTIONS OF NIAGARA FRONTIER. WITH PRECIPITABLE WATER
VALUES BETWEEN 1.50 AND 1.75 INCHES...LOCALLY HIGHER AMOUNTS ARE
POSSIBLE...BUT GIVEN THE TIME BETWEEN WAVES IT WOULD LIKELY TAKE
SLOW MOVING OR TRAINING CONVECTION TO CAUSE ANY FLOODING. THIS
POTENTIAL APPEARS TO BE LIMITED.
OTHERWISE...TEMPERATURES WILL REMAIN FAIRLY STEADY THROUGH THE
REMAINDER OF THE AFTERNOON...TOPPING OUT IN THE UPPER 60S TO LOWER
70S. THEN FOR TONIGHT...EXPECT ONLY MODEST DROP INTO THE LOWER TO
MID 60S. PATCHY FOG MAY DEVELOP AS THE SURFACE LOW CROSSES THE
LAKES THIS EVENING.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
THE BULK OF THE RAIN WILL MOVE OFF TO THE NORTH AND EAST AS THE
SURFACE LOW CROSSES NEW YORK STATE DURING TUESDAY. WILL SEE SOME
REGENERATION OF THE LOW ACROSS NORTHERN NY AND NEW ENGLAND ON
TUESDAY NIGHT AS THE UPPER LOW DEEPENS WHEN IT INTERCEPTS ANOTHER JET
STREAK. WILL HAVE LINGERING LIKELY POPS ACROSS THE LOWER SAINT
LAWRENCE VALLEY...ON THE RIVER BUT OUTSIDE OF OUR FORECAST
AREA...AND WANING CHANCE POPS FOR THE REST OF THE FORECAST AREA FOR
TUESDAY NIGHT.
AN UNSETTLED UPPER LEVEL PATTERN WILL KEEP THE NEED FOR CHANCE POPS
DURING WEDNESDAY AS A SERIES OF WAVES AND VORTICITY MAXIMA ALOFT
STREAM BY IN THE NORTHWESTERLY FLOW. WEAK LOW PRESSURE PASSING BY TO
THE SOUTH WILL BRING SOME HIGHER CHANCE POPS ACROSS THE SOUTHERN
TIER FOR WED AFTERNOON AND EVENING. A WEAK REGION OF HIGH PRESSURE
WILL SETTLE OVER NEW YORK STATE WEDNESDAY NIGHT WITH A CLEARING
TREND AND BREAK FROM THE RAIN CHANCES.
TEMPERATURES WILL BE SLIGHTLY BELOW NORMAL ON TUESDAY AS THE
DEPARTING LOW DRAWS DOWN SOME MARGINALLY COOLER AIR IN ITS WAKE.
HIGHS WILL BE IN THE MID 60S ACROSS THE NORTH COUNTRY TO THE UPPER
60S AND LOW 70S ELSEWHERE. LOWS TUESDAY NIGHT IN THE MID TO UPPER
50S WILL REFLECT THE REMNANT MOISTURE FROM THE PREVIOUS RAINFALL AND
LACK OF ANY REAL AIRMASS CHANGE FOLLOWING THE DEPARTURE OF THE
SURFACE LOW. AN INFLUX OF WARMER AIR ALONG AND AHEAD OF WEAK LOW
PRESSURE WILL BUMP HIGH TEMPS UP A BIT ON WEDNESDAY WITH HIGHS IN
THE LOWER 70S ACROSS THE NORTH COUNTRY AND THE MID 70S ELSEWHERE.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
ON THURSDAY...A WEAK SURFACE RIDGE SHOULD BE IN PLACE OVER NY...WITH
DRY WEATHER EXPECTED. A BACK DOOR COLD FRONT MAY MOVE ACROSS THE
NORTH COUNTRY ON FRIDAY...BUT OTHER THAN KNOCK OFF A FEW DEGREES
FROM DAYTIME HIGHS...THIS SHOULD HAVE LITTLE IF ANY EFFECT ON THE
WEATHER. HIGH PRESSURE HAS BEEN FORECAST FOR DAYS NOW OVER THE
STATE FOR SATURDAY FOR A HIGH CONFIDENCE DRY DAY. SUNDAY IS NOT
QUITE LOCKED IN HOWEVER...WITH SEVERAL MODELS BRINGING THE NEXT
ROUND OF SHOWERS INTO THE STATE. THE LATEST GFS HOLDS THIS OFF UNTIL
SUNDAY EVENING. FOR TEMPERATURES...WITHOUT ANY PRONOUNCED RIDGING
OR TROUGHING OVER THE REGION...EXPECT HIGHS AND LOWS THROUGHOUT THE
LATTER HALF OF THE WEEK TO BE WITHIN A FEW DEGREES OF NORMAL.
&&
.AVIATION /18Z MONDAY THROUGH SATURDAY/...
LOW PRESSURE WILL LIFT FROM THE OHIO VALLEY AND ACROSS LAKE
ERIE/ONTARIO TONIGHT. AHEAD OF THIS...EXPECT MIXED CONDITIONS IN
AND OUT OF SHOWERS...WITH PREDOMINANTLY VFR/MVFR CONDITIONS AT MOST
TAF LOCATIONS. STEADIER RAINS WILL MOVE IN WITH THE LOW...WITH
CIGS EXPECTED TO DROP SIGNIFICANTLY WITH THE WIND SHIFT AS THE LOW
PASSES THROUGH. IFR CONDITIONS ARE LIKELY LATE TONIGHT IN LOW
CIGS...AND LINGERING RAIN SHOWERS. THERE IS A SLIGHT CHANCE OF A
THUNDERSTORM THIS EVENING...WITH WIDESPREAD LIGHTNING UNLIKELY.
ON TUESDAY...EXPECT IFR CONDITIONS TO GRADUALLY IMPROVE TO MVFR/VFR
AS DRIER AIR BUILDS IN. THIS MAY TAKE MOST OF THE DAY...WITH THE
UPPER TROF SLOWLY EXITING EAST OF THE REGION DURING THE AFTERNOON
HOURS
OUTLOOK...
TUESDAY...MVFR WITH SHOWERS.
WEDNESDAY...MVFR IMPROVING TO VFR.
THURSDAY AND FRIDAY...MAINLY VFR.
&&
.MARINE...
EASTERLY WINDS WILL INCREASE TODAY AHEAD OF AN AREA OF LOW PRESSURE
PUSHING INTO THE OHIO VALLEY..PRODUCING SOME CHOPPY WAVE CONDITIONS
ON WESTERN LAKE ONTARIO ALTHOUGH CONDITIONS ARE EXPECTED TO REMAIN
BELOW SMALL CRAFT ADVISORY CRITERIA. THIS LOW WILL PASS JUST NORTH
OF THE REGION TUESDAY AND COULD POSSIBLY PRODUCE A BRIEF PERIOD OF
SMALL CRAFT CONDITIONS ON LAKE ERIE AS WINDS FUNNEL DOWN THE LAKE.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...TMA
NEAR TERM...APFFEL
SHORT TERM...WCH
LONG TERM...ZAFF
AVIATION...APFFEL
MARINE...APFFEL/TMA
AREA FORECAST DISCUSSION
NWS BUFFALO NY
1056 AM EDT MON JUN 10 2013
.SYNOPSIS...
WEAK HIGH PRESSURE WILL DRIFT AWAY FROM THE REGION ALLOWING AN
AREA OF LOW PRESSURE TO MOVE IN FROM THE OHIO VALLEY. THIS LOW
WILL SLOWLY CROSS THE REGION TODAY AND TUESDAY WITH WIDESPREAD
RAIN AND PERHAPS A FEW THUNDERSTORMS. DRY WEATHER WILL RETURN
WEDNESDAY AND SHOULD CONTINUE THROUGH THE REST OF THE WEEK AS HIGH
PRESSURE BUILDS INTO THE GREAT LAKES.
&&
.NEAR TERM /THROUGH TONIGHT/...
A MID LEVEL LOW AND ASSOCIATED SURFACE LOW WILL PUSH INTO THE
OHIO VALLEY TODAY. AHEAD OF THESE FEATURES...MATURING LOW LEVEL
JET WILL EFFICIENTLY TRANSPORT MOIST SUBTROPICAL AIRMASS
NORTHWARD...WITH ANOMALOUS PRECIPITABLE WATER VALUES SURGING INTO
THE REGION. NORTHWARD LIFTING SURFACE WARM FRONT WILL ENHANCE
RAINFALL POTENTIAL. ALL RESULTING IN A WIDESPREAD SOAKING RAINFALL
FOR WESTERN AND CENTRAL NEW YORK THROUGH TONIGHT.
WPC QPF THROUGH TONIGHT SHOWING WIDESPREAD AMOUNTS AROUND ONE
INCH. HOWEVER...SOME OF THE HIGHER RESOLUTION GUIDANCE WOULD
SUPPORT AMOUNTS UP TO TWO INCHES POSSIBLE. AMOUNTS THIS HIGH WOULD
LIKELY ONLY BE POSSIBLE IF WE CAN GET SOME TRAINING CONVECTIVE
ELEMENTS. SURFACE BASED INSTABILITY WILL BE GREATLY LACKING IN
ABUNDANT CLOUD COVER AND SHOWERS...BUT SOME ELEVATED INSTABILITY
IS PRESENT. THERE ALSO MAY BE ENHANCEMENT ALONG A CONVERGENCE
BOUNDARY ACROSS THE NIAGARA FRONTIER...BUT THE HRRR AND MOST MODEL
GUIDANCE HAS THIS BOUNDARY NORTH OF THE BUFFALO CREEK BASINS.
CONSIDERING THE WET SOIL CONDITIONS THERE MAY BE SOME NUISANCE
HYDROLOGIC CONCERNS THAT WILL NEED TO BE MONITORED...BUT AT THIS
POINT WIDESPREAD FLOODING IS NOT ANTICIPATED. WILL CONTINUE TO
MENTION THREAT IN HWO PRODUCT.
OTHERWISE...TEMPERATURES WILL ONLY RISE MODESTLY THIS AFTERNOON
WITH HIGHS RANGING FROM THE UPPER 60S TO LOWER 70S.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
THE BULK OF THE RAIN WILL MOVE OFF TO THE NORTH AND EAST AS THE
SURFACE LOW CROSSES NEW YORK STATE DURING TUESDAY. WILL SEE SOME
REGENERATION OF THE LOW ACROSS NORTHERN NY AND NEW ENGLAND ON
TUESDAY NIGHT AS THE UPPER LOW DEEPENS WHEN IT INTERCEPTS ANOTHER JET
STREAK. WILL HAVE LINGERING LIKELY POPS ACROSS THE LOWER SAINT
LAWRENCE VALLEY...ON THE RIVER BUT OUTSIDE OF OUR FORECAST
AREA...AND WANING CHANCE POPS FOR THE REST OF THE FORECAST AREA FOR
TUESDAY NIGHT.
AN UNSETTLED UPPER LEVEL PATTERN WILL KEEP THE NEED FOR CHANCE POPS
DURING WEDNESDAY AS A SERIES OF WAVES AND VORTICITY MAXIMA ALOFT
STREAM BY IN THE NORTHWESTERLY FLOW. WEAK LOW PRESSURE PASSING BY TO
THE SOUTH WILL BRING SOME HIGHER CHANCE POPS ACROSS THE SOUTHERN
TIER FOR WED AFTERNOON AND EVENING. A WEAK REGION OF HIGH PRESSURE
WILL SETTLE OVER NEW YORK STATE WEDNESDAY NIGHT WITH A CLEARING
TREND AND BREAK FROM THE RAIN CHANCES.
TEMPERATURES WILL BE SLIGHTLY BELOW NORMAL ON TUESDAY AS THE
DEPARTING LOW DRAWS DOWN SOME MARGINALLY COOLER AIR IN ITS WAKE.
HIGHS WILL BE IN THE MID 60S ACROSS THE NORTH COUNTRY TO THE UPPER
60S AND LOW 70S ELSEWHERE. LOWS TUESDAY NIGHT IN THE MID TO UPPER
50S WILL REFLECT THE REMNANT MOISTURE FROM THE PREVIOUS RAINFALL AND
LACK OF ANY REAL AIRMASS CHANGE FOLLOWING THE DEPARTURE OF THE
SURFACE LOW. AN INFLUX OF WARMER AIR ALONG AND AHEAD OF WEAK LOW
PRESSURE WILL BUMP HIGH TEMPS UP A BIT ON WEDNESDAY WITH HIGHS IN
THE LOWER 70S ACROSS THE NORTH COUNTRY AND THE MID 70S ELSEWHERE.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
ON THURSDAY...A WEAK SURFACE RIDGE SHOULD BE IN PLACE OVER NY...WITH
DRY WEATHER EXPECTED. A BACK DOOR COLD FRONT MAY MOVE ACROSS THE
NORTH COUNTRY ON FRIDAY...BUT OTHER THAN KNOCK OFF A FEW DEGREES
FROM DAYTIME HIGHS...THIS SHOULD HAVE LITTLE IF ANY EFFECT ON THE
WEATHER. HIGH PRESSURE HAS BEEN FORECAST FOR DAYS NOW OVER THE
STATE FOR SATURDAY FOR A HIGH CONFIDENCE DRY DAY. SUNDAY IS NOT
QUITE LOCKED IN HOWEVER...WITH SEVERAL MODELS BRINGING THE NEXT
ROUND OF SHOWERS INTO THE STATE. THE LATEST GFS HOLDS THIS OFF UNTIL
SUNDAY EVENING. FOR TEMPERATURES...WITHOUT ANY PRONOUNCED RIDGING
OR TROUGHING OVER THE REGION...EXPECT HIGHS AND LOWS THROUGHOUT THE
LATTER HALF OF THE WEEK TO BE WITHIN A FEW DEGREES OF NORMAL.
&&
.AVIATION /14Z MONDAY THROUGH FRIDAY/...
AN AREA OF LOW PRESSURE WILL PUSH INTO THE OHIO VALLEY TODAY.
INCREASING MOISTURE AND ASCENT AHEAD OF THIS FEATURE WILL BRING
SHOWERS INTO WESTERN NY THROUGH THIS EVENING. INITIALLY...THE SE
FLOW WILL HELP KEEP VFR CIGS THROUGH EARLY AFTERNOON AT
BUF/IAG/ROC DUE TO THE DOWNSLOPE WIND DIRECTION. BY MID-
AFTERNOON...STEADIER SHOWERS WILL MOVE IN...WITH INCREASING
MOISTURE. CIGS SHOULD GRADUALLY LOWER...WITH HEAVIER SHOWERS AND
POSSIBLY A THUNDERSTORM EMBEDDED.
THE LOW WILL LIFT ACROSS THE REGION TONIGHT...WITH WINDS SHIFTING
WITH THE PASSAGE OF THE LOW. THIS WIND SHIFT WILL KEY A DROP IN
CIGS...WITH A PERIOD OF IFR CONDITIONS LIKELY AT MOST SITES. AHEAD
OF THE LOW...EXPECT LIFR CONDITIONS WEST OF LAKE ONTARIO...BUT AT
THIS TIME IT APPEARS THE SE FLOW WILL HOLD AT OUR TAF
LOCATIONS...WITH IAG THE ONLY CLOSE CALL.
OUTLOOK...
TUESDAY...MVFR WITH SHOWERS.
WEDNESDAY...MVFR IMPROVING TO VFR.
THURSDAY AND FRIDAY...MAINLY VFR.
&&
.MARINE...
EASTERLY WINDS WILL INCREASE TODAY AHEAD OF AN AREA OF LOW PRESSURE
PUSHING INTO THE OHIO VALLEY..PRODUCING SOME CHOPPY WAVE CONDITIONS
ON WESTERN LAKE ONTARIO ALTHOUGH CONDITIONS ARE EXPECTED TO REMAIN
BELOW SMALL CRAFT ADVISORY CRITERIA. THIS LOW WILL PASS JUST NORTH
OF THE REGION TUESDAY AND COULD POSSIBLY PRODUCE A BRIEF PERIOD OF
SMALL CRAFT CONDITIONS ON LAKE ERIE AS WINDS FUNNEL DOWN THE LAKE.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...TMA
NEAR TERM...APFFEL/TMA
SHORT TERM...WCH
LONG TERM...ZAFF
AVIATION...APFFEL/TMA
MARINE...APFFEL/TMA
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
752 AM EDT MON JUN 10 2013
.SYNOPSIS...
SHOWERS AND THUNDERSTORMS WITH HEAVY RAIN ARE EXPECTED TODAY AHEAD
OF A WEAKENING COLD FRONT. ABOVE NORMAL TEMPERATURES WILL DEVELOP
TUESDAY THROUGH THURSDAY. ANOTHER COLD FRONT WILL MOVE ACROSS LATE
THURSDAY NIGHT. DRY AND RELATIVELY COOL HIGH PRESSURE WILL BUILD IN
FRIDAY THROUGH NEXT WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 645 AM MONDAY...EACH SUCCESSIVE RUN OF THE HRRR PAINTS A
DIFFERENT VERSION OF THE SAME STORY: DAYTIME HEATING IS GOING TO
IGNITE A LARGE NUMBER OF SHOWER AND THUNDERSTORM CLUSTERS
ACROSS THE CENTRAL AND EASTERN CAROLINAS TODAY. GIVEN LOW LEVEL
WINDS BLOWING ONSHORE...THE IMMEDIATE BEACHES WILL SEE A MINIMA IN
PRECIPITATION COVERAGE ONCE THE SEABREEZE HAS BEGUN BLOWING BY LATE
MORNING. THE HIGHEST COVERAGE OF CONVECTION...80-90 PERCENT...IS
STILL ANTICIPATED ALONG AND WEST OF INTERSTATE 95. I HAVE TWEAKED
FORECAST HIGHS UP A DEGREE IN SPOTS...OTHERWISE NO SIGNIFICANT
CHANGES. PREVIOUS DISCUSSION FROM 330 AM FOLLOWS...
MID-JUNE IS SUPPOSED TO BE THE TIME OF THE YEAR WHEN THE
MID-LATITUDE STORM TRACK PULLS NORTH TOWARD THE CANADIAN BORDER AND
WE MOVE INTO A TROPICAL PATTERN GOVERNED BY MARITIME FLOW OFF THE
ATLANTIC...DAILY SEA BREEZES AND AFTERNOON THUNDERSTORMS. NOT SO
TODAY AT LEAST: AN IMPRESSIVE UPPER TROUGH OVER ILLINOIS WILL MOVE
EAST ACROSS THE CENTRAL APPALACHIANS TONIGHT...DRIVING A SURFACE
COLD FRONT EASTWARD INTO THE EASTERN CAROLINAS.
AHEAD OF THIS FRONT WE HAVE A MARITIME TROPICAL AIRMASS WITH
PRECIPITABLE WATER NEAR 2.0 INCHES AND SURFACE DEWPOINTS IN THE 70S.
WITH THE LOW LEVEL FLOW ALMOST IDENTICAL IN SPEED AND DIRECTION TO
THE 850-300 MB STEERING FLOW...WHAT COULD ALMOST BE TERMED A
REGENERATIVE MCS WAS THE RESULT SUNDAY EVENING ACROSS PENDER COUNTY
WITH RADAR ESTIMATES OF 4-7 INCHES OF RAIN BETWEEN BURGAW AND MOORES
CREEK BATTLEFIELD. ALTHOUGH A BROADLY DIFFLUENT UPPER PATTERN EXISTS
ACROSS THE AREA DUE TO A JET STREAK CURRENTLY OVER NEW ENGLAND AND A
SECOND JET STREAK DEVELOPING ACROSS THE MID-ATLANTIC TONIGHT...THE
925 MB LOW LEVEL JET SHOULD NOT KEEP UP WITH INCREASES IN THE WIND
SPEEDS ALOFT. THIS DISPARITY SHOULD FAVOR FORWARD-PROPAGATING CELLS
AND FASTER OVERALL STORM MOTION ON THE ORDER OF 25-30 MPH TODAY.
FORECAST RAINFALL THROUGH TONIGHT RANGES FROM 1.25 INCHES ALONG THE
I-95 CORRIDOR TO 0.6 INCHES ON THE NC COAST...WITH POPS 80 PERCENT
OR HIGHER ALONG AND WEST OF INTERSTATE 95. ALTHOUGH A FLOOD WATCH
WAS CONTEMPLATED...TODAY`S FASTER CELL MOTION SHOULD HELP REDUCE THE
POTENTIAL FOR EXCESSIVE (3+ INCH) RAINFALL TOTALS AT ANY ONE
LOCATION...CONFIRMED BY LOW NUMBERS IN THE SREF 24 HOUR 1" AND 2"
RAINFALL PROBABILITIES.
THE SURFACE COLD FRONT SHOULD MOVE INTO THE AREA FROM WEST TO EAST
LATE TONIGHT. MODELS ARE NOT SHOWING THIS FRONT CLEANLY MOVING
OFFSHORE...THEREFORE I CANNOT SHOW A PRONOUNCED CLEARING OR DRYING
TREND IN THE FORECAST EVEN LATE TONIGHT. THE HIGHEST POPS SHOULD
TRANSITION EAST OF INTERSTATE 95 DURING THE EVENING HOURS...
APPROACHING THE COAST BY MIDNIGHT WHERE I HAVE 60 POPS FORECAST AT
MYRTLE BEACH AND WILMINGTON. SOME DRIER AIR WILL ARRIVE ALOFT BY
MIDNIGHT AS THE STEERING FLOW ACQUIRES A MORE WESTERLY COMPONENT...
AND THE POTENTIAL FOR HEAVY RAIN WILL DIMINISH.
IN BETWEEN CLOUDS AND SHOWERS TODAY`S HIGHS SHOULD REACH THE MID 80S
IN MOST AREAS. LOWS TONIGHT WILL RANGE FROM 69-73...WARMEST AT THE
COAST.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 3 AM MONDAY...
MUCH DRIER AIR WILL ADVECT INTO THE AREA THROUGH TUESDAY AS FLOW
ALOFT SHIFTS AROUND TO THE WEST AND NORTHWEST AHEAD OF ACTUAL ARRIVAL
OF SURFACE FRONT BY WED MORNING. PCP WATER VALUES WILL BE DOWN LESS
THAN 1.5 INCHES AS LOW TO MID LEVEL TROUGH EXITS THE COAST. WITH
SUBSIDENCE AND DRY AIR ON THE BACK END EXPECT ANY LINGERING PCP TO
DIMINISH THROUGH THE DAY. RESIDUAL MOISTURE FROM RAIN ON MONDAY WILL
PRODUCE CU AND MAY SEE ENOUGH CONVERGENCE ALONG THE SEA BREEZE TO
PRODUCE A SHOWER OR TWO THROUGH THE AFTN...BUT OVERALL ALL SHWRS
SHOULD END EARLY IN THE DAY. BEST CHC OF PCP LATER IN THE DAY WILL
BE CLOSER TO THE COAST AS WESTERLY COMPONENT TO FLOW SHOULD KEEP
BEST CONVERGENCE CLOSER TO THE COAST...NOT ALLOWING SEA BREEZE TO
MOVE TOO FAR INLAND.
THE ACTUAL SURFACE FEATURE WILL BECOME DIFFUSE AS IT REACHES THE
COAST BY WED MORNING. THE SFC WINDS WILL VEER AROUND TO THE WEST
ONLY BRIEFLY BEFORE BACKING TO THE SW AS PIEDMONT TROUGH REMAINS
MORE PRONOUNCED INLAND. WITH STRONG WESTERLY COMPONENT TO THE FLOW
EXPECT ANY CONVERGENCE ALONG THE SEA BREEZE TO REMAIN CLOSE TO THE
COAST. RIDGE BUILDS UP FROM THE GULF BUT A SHORTWAVE ON THE
NORTHEAST EDGE OF RIDGE RIDES THROUGH THE LOCAL AREA WED
AFTERNOON WHICH COULD HELP TO ENHANCE CU DEVELOPMENT AND POSSIBLY
AN ISOLATED SHWR. FOR NOW WILL KEEP ANY POPS OUT OF FORECAST WITH
SO MUCH DRY AIR IN PLACE ALOFT.
AS FOR TEMPS...THE WESTERLY DOWNSLOPE FLOW WILL ALSO AID IN
COMPRESSIONAL WARMING BOTH TUES AND WED PRODUCING TEMPS ABOVE
NORMAL...INTO THE 90S MOST PLACES. THE 850 TEMPS RISE THROUGH THE
PERIOD FROM AROUND 20C ON WED TO 21C ON THURS. OVERALL EXPECT A
VERY WARM MID WEEK. ALTHOUGH A GOOD DEAL OF DRY AIR MAKES IT INTO
AREA ALOFT...SFC DEWPOINTS ONLY DROP A COUPLE OF DEGREES...STILL
HOLDING UP CLOSER TO 70. THEREFORE OVERNIGHT LOWS WILL REMAIN UP
CLOSER TO 70 ALSO.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
AS OF 3 AM MONDAY...MID TO UPPER RIDGE GETS SUPPRESSED TO THE
SOUTH AS SHORTWAVE DIGS SOUTH FROM THE GREAT LAKES ON THURS. THIS
WHOLE SYSTEM MOVES EAST DRAGGING A COLD FRONT THROUGH THE AREA
THURS NIGHT. ALTHOUGH THE SURFACE FLOW IS SOUTHERLY ON THURS THE
WINDS ALOFT MAINTAIN MORE OF A WESTERLY DIRECTION. OVERALL DO NOT
EXPECT TOO MUCH MOISTURE RETURN THROUGH THE MID TO UPPER LEVELS
AND THEREFORE EXPECT MOST OF THE CONVECTIVE ACTIVITY ON THURS TO
COME LATER IN THE DAY AS COLD FRONT MAKES ITS WAY THROUGH THE
CAROLINAS. THEREFORE WILL KEEP LOW END POPS ASSOCIATED WITH
LOCALIZED SHWR ACTIVITY THURS AFTN AND INCREASING CHC OF
SHWRS/TSTMS THURS NIGHT AS FRONT MOVES THROUGH.
COLD FRONT SHOULD CLEAR THE COAST BY FRI MORNING BUT SOME
LINGERING SHWRS ARE POSSIBLE ALONG THE COAST. DEEP NW FLOW OF
DRIER AND RELATIVELY COOLER AIR WILL ADVECT IN BEHIND COLD FRONT
FRI THROUGH THE WEEKEND AS CANADIAN HIGH PRESSURE BUILDS DOWN.
SOME MINOR PERTURBATIONS IN THE MID LEVEL FLOW WILL MOVE OVER THE
TOP OF STRONG RIDGE BUILDING UP THROUGH THE CENTRAL CONUS. THIS
MAY INDUCE SOME CLOUD DEVELOPMENT BUT OVERALL EXPECT A DRY WEEKEND
WITH PLENTY OF SUNSHINE.
TEMPERATURES ON THURS WILL REACH WELL INTO THE 90S MOST PLACES AS
850 TEMPS HOLD UP AROUND 21C. ONCE COLD FRONT MOVES THROUGH BY
FRI...TEMPS WILL BE KNOCKED BACK DOWN TO NORMAL OR SLIGHTLY
BELOW...IN THE MID 80S MOST PLACES THROUGH THE WEEKEND. OVERNIGHT
LOWS WILL BE BACK DOWN TO NORMAL AS WELL WITH READINGS IN THE MID
60S.
&&
.AVIATION /12Z MONDAY THROUGH FRIDAY/...
AS OF 12Z...EXPECT IFR/TEMPO MVFR CIGS INLAND TERMINALS TO RISE
TO MVFR BY 13-14Z AND REMAIN MVFR THROUGH MUCH OF THIS MORNING AND
AFTERNOON. MVFR/TEMPO VFR CIGS CAN BE EXPECTED AT THE COASTAL
TERMINALS AS THE SEA BREEZE/RESULTANT BOUNDARY DEVELOPS THIS
MORNING. CIGS SHOULD RISE TO MOSTLY VFR WITH LOW CHANCES OF MVFR
LATE THIS MORNING PERSISTING INTO THE AFTERNOON AND EARLY EVENING.
PER RADAR THERE IS MODERATE CONFIDENCE A TEMPO LIGHT SHOWER COULD
OCCUR AT KILM THROUGH 13-14Z. BY 15Z AS THE SEA BREEZE/RESULTANT
BOUNDARY INITIALLY STAYS PINNED NEAR THE COAST THERE WILL BE A
CHANCE OF SHOWER OCCURRENCE AT ALL COASTAL TERMINALS...BUT CONFIDENCE
IS LOWER. SHOWERS SHOULD BE MAINLY INLAND OF THE COASTAL TERMINALS
LATE MORNING/EARLY AFTERNOON.
EXPECT SCATTERED TO NUMEROUS SHOWERS/ISOLATED THUNDERSTORMS TO
DEVELOP THIS MORNING BETWEEN THE INLAND AND COASTAL TERMINALS.
THERE IS MODERATE CONFIDENCE KFLO/KLBT WILL BE AFFECTED BY THIS
ACTIVITY FROM MID-MORNING THROUGHOUT THE AFTERNOON...WITH ACTIVITY
BECOMING ISOLATED IN THE EVENING AS MOST OF THE CONVECTION SHIFTS
TO THE COASTAL TERMINALS. MVFR/TEMPO IFR WILL BE POSSIBLE IN ANY
PRECIPITATION.
SHOWERS WILL BECOME ISOLATED IN THE PRE-DAWN HOURS AT THE COASTAL
TERMINALS AS SLIGHTLY DRIER AIR FILTERS IN. AT KFLO/KLBT IFR/LIFR IN
FOG WILL BE POSSIBLE AFTER 09Z.
EXTENDED OUTLOOK...ISOLATED SHOWERS/THUNDERSTORMS WITH TEMPO PERIODS
OF MVFR/IFR POSSIBLE TUESDAY AND THURSDAY. OTHERWISE VFR.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 730 AM MONDAY...WINDS APPEAR TO BE STRONGER AT THE BEACHES
THAN THEY ARE OFFSHORE AT FRYING PAN SHOALS BUOY. SMALL INITIAL
ADJUSTMENTS HAVE BEEN MADE FOR THIS...OTHERWISE THE TREND OF SLOWLY
INCREASING WINDS THROUGH TONIGHT REMAINS UNCHANGED. PREVIOUS
DISCUSSION FROM 330 AM FOLLOWS...
THE PRESSURE GRADIENT BETWEEN BERMUDA HIGH PRESSURE WELL OFFSHORE
AND A COLD FRONT ADVANCING EASTWARD ACROSS THE MISSISSIPPI VALLEY
WILL CREATE STRENGTHENING SOUTH WINDS TODAY AND TONIGHT. WIND SPEEDS
CURRENTLY AROUND 15 KNOTS WILL INCREASE TO 15-20 KNOTS BY EARLY THIS
EVENING...VEERING MORE SOUTHWESTERLY WITH TIME TONIGHT. THIS SHOULD
LEAD TO BUILDING SEAS...WITH THE POTENTIAL FOR 6 FOOT SEAS ACROSS
THE NC WATERS NECESSITATING A SMALL CRAFT ADVISORY FOR THIS AREA
TONIGHT THROUGH TUESDAY. SCATTERED SHOWERS THIS MORNING WILL SHIFT
MAINLY INLAND BY LATE MORNING...BUT WAVES OF SHOWERS AND
THUNDERSTORMS ARE EXPECTED TO PUSH BACK OFFSHORE THIS EVENING AND
OVERNIGHT AS THE COLD FRONT APPROACHES FROM THE WEST.
SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 3 AM MONDAY...WINDS AND SEAS WILL BE CLOSE TO SCA THRESHOLDS
AT THE START OF THE SHORT TERM PERIOD. SW WINDS UP TO 15 TO 20 KTS
WILL PUSH SEAS UP CLOSE TO 5 TO 6 FT IN OUTER WATERS AND 3 TO 4 FT
NEAR SHORE. WILL KEEP WITH SCA FOR NORTHERN 2 MARINE ZONES ONLY
THROUGH THE DAY ON TUES. WINDS WILL VEER AROUND AS COLD FRONT
APPROACHES LATE TUES INTO EARLY WED. THIS WEAKENING OFF SHORE FLOW
AROUND 10 TO 15 KTS WILL ALLOW SEAS TO SUBSIDE DOWN TO 2 TO 4 FT
THROUGH WED.
WINDS AND SEAS WILL INCREASE AGAIN LATE WED INTO THURS AS GRADIENT
TIGHTENS FIRST DUE TO MORE PRONOUNCED PIEDMONT TROUGH INLAND AND
THEN DUE TO APPROACH OF COLD FRONT BY THURS. EXPECT SW WINDS BACK
UP TO A SOLID 15 KTS OR SO BY THURS MORNING WITH SEAS UP AROUND 4
TO 5 FT IN OUTER WATERS.
LONG TERM /THURSDAY THROUGH FRIDAY/...
AS OF 3 AM MONDAY...TIGHTENING GRADIENT FLOW AHEAD OF AN APPROACHING
COLD FRONT WILL PRODUCE SW WINDS UP TO 15 TO 20 KTS. MAY EVEN SEA
WINDS UP CLOSE TO 25 KTS JUST AHEAD OF COLD FRONT LATE THURS NIGHT
INTO EARLY FRI. THIS WILL PUSH SEAS UP TO 6 TO 7 FT IN OUTER
WATERS THURS NIGHT.
BY FRIDAY...THE WINDS WILL VEER AROUND ABRUPTLY TO THE NW-N
BEHIND COLD FRONT AND WILL DIMINISH DOWN TO 10 TO 15 KTS. SEAS
WILL DROP BACK DOWN TO 2 TO 4 FT ON FRI. WINDS WILL CONTINUE TO
VEER AROUND BECOMING MORE ON SHORE BUT LIGHT THROUGH THE WEEKEND AS
HIGH PRESSURE SHIFTS DOWN FROM THE NORTH MOVING CLOSER OVERHEAD
OVER THE WEEKEND.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 8 PM THIS EVENING TO 6 PM EDT
TUESDAY FOR AMZ250-252.
&&
$$
NEAR TERM...TRA
SHORT TERM...RGZ
LONG TERM...RGZ
AVIATION...MRR
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
655 AM EDT MON JUN 10 2013
.SYNOPSIS...
SHOWERS AND THUNDERSTORMS WITH HEAVY RAIN ARE EXPECTED TODAY AHEAD
OF A WEAKENING COLD FRONT. ABOVE NORMAL TEMPERATURES WILL DEVELOP
TUESDAY THROUGH THURSDAY. ANOTHER COLD FRONT WILL MOVE ACROSS LATE
THURSDAY NIGHT. DRY AND RELATIVELY COOL HIGH PRESSURE WILL BUILD IN
FRIDAY THROUGH NEXT WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 645 AM MONDAY...EACH SUCCESSIVE RUN OF THE HRRR PAINTS A
DIFFERENT VERSION OF THE SAME STORY: DAYTIME HEATING IS GOING TO
IGNITE A LARGE NUMBER OF SHOWER AND THUNDERSTORM CLUSTERS
ACROSS THE CENTRAL AND EASTERN CAROLINAS TODAY. GIVEN LOW LEVEL
WINDS BLOWING ONSHORE...THE IMMEDIATE BEACHES WILL SEE A MINIMA IN
PRECIPITATION COVERAGE ONCE THE SEABREEZE HAS BEGUN BLOWING BY LATE
MORNING. THE HIGHEST COVERAGE OF CONVECTION...80-90 PERCENT...IS
STILL ANTICIPATED ALONG AND WEST OF INTERSTATE 95. I HAVE TWEAKED
FORECAST HIGHS UP A DEGREE IN SPOTS...OTHERWISE NO SIGNIFICANT
CHANGES. PREVIOUS DISCUSSION FROM 330 AM FOLLOWS...
MID-JUNE IS SUPPOSED TO BE THE TIME OF THE YEAR WHEN THE
MID-LATITUDE STORM TRACK PULLS NORTH TOWARD THE CANADIAN BORDER AND
WE MOVE INTO A TROPICAL PATTERN GOVERNED BY MARITIME FLOW OFF THE
ATLANTIC...DAILY SEABREEZES AND AFTERNOON THUNDERSTORMS. NOT SO
TODAY AT LEAST: AN IMPRESSIVE UPPER TROUGH OVER ILLINOIS WILL MOVE
EAST ACROSS THE CENTRAL APPALACHIANS TONIGHT...DRIVING A SURFACE
COLD FRONT EASTWARD INTO THE EASTERN CAROLINAS.
AHEAD OF THIS FRONT WE HAVE A MARITIME TROPICAL AIRMASS WITH
PRECIPITABLE WATER NEAR 2.0 INCHES AND SURFACE DEWPOINTS IN THE 70S.
WITH THE LOW LEVEL FLOW ALMOST IDENTICAL IN SPEED AND DIRECTION TO
THE 850-300 MB STEERING FLOW...WHAT COULD ALMOST BE TERMED A
REGENERATIVE MCS WAS THE RESULT SUNDAY EVENING ACROSS PENDER COUNTY
WITH RADAR ESTIMATES OF 4-7 INCHES OF RAIN BETWEEN BURGAW AND MOORES
CREEK BATTLEFIELD. ALTHOUGH A BROADLY DIFLUENT UPPER PATTERN EXISTS
ACROSS THE AREA DUE TO A JET STREAK CURRENTLY OVER NEW ENGLAND AND A
SECOND JET STREAK DEVELOPING ACROSS THE MID-ATLANTIC TONIGHT...THE
925 MB LOW LEVEL JET SHOULD NOT KEEP UP WITH INCREASES IN THE WIND
SPEEDS ALOFT. THIS DISPARITY SHOULD FAVOR FORWARD-PROPAGATING CELLS
AND FASTER OVERALL STORM MOTION ON THE ORDER OF 25-30 MPH TODAY.
FORECAST RAINFALL THROUGH TONIGHT RANGES FROM 1.25 INCHES ALONG THE
I-95 CORRIDOR TO 0.6 INCHES ON THE NC COAST...WITH POPS 80 PERCENT
OR HIGHER ALONG AND WEST OF INTERSTATE 95. ALTHOUGH A FLOOD WATCH
WAS CONTEMPLATED...TODAY`S FASTER CELL MOTION SHOULD HELP REDUCE THE
POTENTIAL FOR EXCESSIVE (3+ INCH) RAINFALL TOTALS AT ANY ONE
LOCATION...CONFIRMED BY LOW NUMBERS IN THE SREF 24 HOUR 1" AND 2"
RAINFALL PROBABILITIES.
THE SURFACE COLD FRONT SHOULD MOVE INTO THE AREA FROM WEST TO EAST
LATE TONIGHT. MODELS ARE NOT SHOWING THIS FRONT CLEANLY MOVING
OFFSHORE...THEREFORE I CANNOT SHOW A PRONOUNCED CLEARING OR DRYING
TREND IN THE FORECAST EVEN LATE TONIGHT. THE HIGHEST POPS SHOULD
TRANSITION EAST OF INTERSTATE 95 DURING THE EVENING HOURS...
APPROACHING THE COAST BY MIDNIGHT WHERE I HAVE 60 POPS FORECAST AT
MYRTLE BEACH AND WILMINGTON. SOME DRIER AIR WILL ARRIVE ALOFT BY
MIDNIGHT AS THE STEERING FLOW ACQUIRES A MORE WESTERLY COMPONENT...
AND THE POTENTIAL FOR HEAVY RAIN WILL DIMINISH.
IN BETWEEN CLOUDS AND SHOWERS TODAY`S HIGHS SHOULD REACH THE MID 80S
IN MOST AREAS. LOWS TONIGHT WILL RANGE FROM 69-73...WARMEST AT THE
COAST.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 3 AM MONDAY...
MUCH DRIER AIR WILL ADVECT INTO THE AREA THROUGH TUESDAY AS FLOW
ALOFT SHIFTS AROUND TO THE WEST AND NORTHWEST AHEAD OF ACTUAL ARRIVAL
OF SURFACE FRONT BY WED MORNING. PCP WATER VALUES WILL BE DOWN LESS
THAN 1.5 INCHES AS LOW TO MID LEVEL TROUGH EXITS THE COAST. WITH
SUBSIDENCE AND DRY AIR ON THE BACK END EXPECT ANY LINGERING PCP TO
DIMINISH THROUGH THE DAY. RESIDUAL MOISTURE FROM RAIN ON MONDAY WILL
PRODUCE CU AND MAY SEE ENOUGH CONVERGENCE ALONG THE SEA BREEZE TO
PRODUCE A SHOWER OR TWO THROUGH THE AFTN...BUT OVERALL ALL SHWRS
SHOULD END EARLY IN THE DAY. BEST CHC OF PCP LATER IN THE DAY WILL
BE CLOSER TO THE COAST AS WESTERLY COMPONENT TO FLOW SHOULD KEEP
BEST CONVERGENCE CLOSER TO THE COAST...NOT ALLOWING SEA BREEZE TO
MOVE TOO FAR INLAND.
THE ACTUAL SURFACE FEATURE WILL BECOME DIFFUSE AS IT REACHES THE
COAST BY WED MORNING. THE SFC WINDS WILL VEER AROUND TO THE WEST
ONLY BRIEFLY BEFORE BACKING TO THE SW AS PIEDMONT TROUGH REMAINS
MORE PRONOUNCED INLAND. WITH STRONG WESTERLY COMPONENT TO THE FLOW
EXPECT ANY CONVERGENCE ALONG THE SEA BREEZE TO REMAIN CLOSE TO THE
COAST. RIDGE BUILDS UP FROM THE GULF BUT A SHORTWAVE ON THE
NORTHEAST EDGE OF RIDGE RIDES THROUGH THE LOCAL AREA WED
AFTERNOON WHICH COULD HELP TO ENHANCE CU DEVELOPMENT AND POSSIBLY
AN ISOLATED SHWR. FOR NOW WILL KEEP ANY POPS OUT OF FORECAST WITH
SO MUCH DRY AIR IN PLACE ALOFT.
AS FOR TEMPS...THE WESTERLY DOWNSLOPE FLOW WILL ALSO AID IN
COMPRESSIONAL WARMING BOTH TUES AND WED PRODUCING TEMPS ABOVE
NORMAL...INTO THE 90S MOST PLACES. THE 850 TEMPS RISE THROUGH THE
PERIOD FROM AROUND 20C ON WED TO 21C ON THURS. OVERALL EXPECT A
VERY WARM MID WEEK. ALTHOUGH A GOOD DEAL OF DRY AIR MAKES IT INTO
AREA ALOFT...SFC DEWPOINTS ONLY DROP A COUPLE OF DEGREES...STILL
HOLDING UP CLOSER TO 70. THEREFORE OVERNIGHT LOWS WILL REMAIN UP
CLOSER TO 70 ALSO.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
AS OF 3 AM MONDAY...MID TO UPPER RIDGE GETS SUPPRESSED TO THE
SOUTH AS SHORTWAVE DIGS SOUTH FROM THE GREAT LAKES ON THURS. THIS
WHOLE SYSTEM MOVES EAST DRAGGING A COLD FRONT THROUGH THE AREA
THURS NIGHT. ALTHOUGH THE SURFACE FLOW IS SOUTHERLY ON THURS THE
WINDS ALOFT MAINTAIN MORE OF A WESTERLY DIRECTION. OVERALL DO NOT
EXPECT TOO MUCH MOISTURE RETURN THROUGH THE MID TO UPPER LEVELS
AND THEREFORE EXPECT MOST OF THE CONVECTIVE ACTIVITY ON THURS TO
COME LATER IN THE DAY AS COLD FRONT MAKES ITS WAY THROUGH THE
CAROLINAS. THEREFORE WILL KEEP LOW END POPS ASSOCIATED WITH
LOCALIZED SHWR ACTIVITY THURS AFTN AND INCREASING CHC OF
SHWRS/TSTMS THURS NIGHT AS FRONT MOVES THROUGH.
COLD FRONT SHOULD CLEAR THE COAST BY FRI MORNING BUT SOME
LINGERING SHWRS ARE POSSIBLE ALONG THE COAST. DEEP NW FLOW OF
DRIER AND RELATIVELY COOLER AIR WILL ADVECT IN BEHIND COLD FRONT
FRI THROUGH THE WEEKEND AS CANADIAN HIGH PRESSURE BUILDS DOWN.
SOME MINOR PERTURBATIONS IN THE MID LEVEL FLOW WILL MOVE OVER THE
TOP OF STRONG RIDGE BUILDING UP THROUGH THE CENTRAL CONUS. THIS
MAY INDUCE SOME CLOUD DEVELOPMENT BUT OVERALL EXPECT A DRY WEEKEND
WITH PLENTY OF SUNSHINE.
TEMPERATURES ON THURS WILL REACH WELL INTO THE 90S MOST PLACES AS
850 TEMPS HOLD UP AROUND 21C. ONCE COLD FRONT MOVES THROUGH BY
FRI...TEMPS WILL BE KNOCKED BACK DOWN TO NORMAL OR SLIGHTLY
BELOW...IN THE MID 80S MOST PLACES THROUGH THE WEEKEND. OVERNIGHT
LOWS WILL BE BACK DOWN TO NORMAL AS WELL WITH READINGS IN THE MID
60S.
&&
.AVIATION /06Z MONDAY THROUGH FRIDAY/...
AS OF 06Z...EXPECT IFR CIGS/VSBYS INLAND AND MVFR/TEMPO IFR CIGS
ALONG THE COAST WITH THE SATURATED LOW-LEVEL ENVIRONMENT. TEMPO
-SHRA ARE ALSO POSSIBLE ALONG THE COAST THIS MORNING WITH SHOWER
ACTIVITY CONTINUING OFFSHORE. SHOWERS AND T-STORMS ARE LIKELY ACROSS
THE AREA TODAY WITH AN UPPER DISTURBANCE AHEAD OF A LARGE UPPER
TROUGH. EXPECT MVFR/VFR TO PREVAIL THRU THE DAY WITH TEMPO IFR IN
HEAVIER DOWNPOURS. S/SW WINDS WILL INCREASE TO 10-15 KTS WITH GUSTS
OF 20 KTS DURING THE AFTN HOURS. HAVE CONTINUED VCSH AT ALL TERMS
THROUGH THE END OF THE TAF PERIOD AS THE TROUGH/FRONT NEARS THE CWA.
EXTENDED OUTLOOK...SHOWERS/T-STORMS WITH PERIODS OF MVFR/IFR THROUGH
TUESDAY. CHANCE OF SHOWERS THURSDAY. OTHERWISE VFR.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 730 AM MONDAY...WINDS APPEAR TO BE STRONGER AT THE BEACHES
THAN THEY ARE OFFSHORE AT FRYING PAN SHOALS BUOY. SMALL INITIAL
ADJUSTMENTS HAVE BEEN MADE FOR THIS...OTHERWISE THE TREND OF SLOWLY
INCREASING WINDS THROUGH TONIGHT REMAINS UNCHANGED. PREVIOUS
DISCUSSION FROM 330 AM FOLLOWS...
THE PRESSURE GRADIENT BETWEEN BERMUDA HIGH PRESSURE WELL OFFSHORE
AND A COLD FRONT ADVANCING EASTWARD ACROSS THE MISSISSIPPI VALLEY
WILL CREATE STRENGTHENING SOUTH WINDS TODAY AND TONIGHT. WIND SPEEDS
CURRENTLY AROUND 15 KNOTS WILL INCREASE TO 15-20 KNOTS BY EARLY THIS
EVENING...VEERING MORE SOUTHWESTERLY WITH TIME TONIGHT. THIS SHOULD
LEAD TO BUILDING SEAS...WITH THE POTENTIAL FOR 6 FOOT SEAS ACROSS
THE NC WATERS NECESSITATING A SMALL CRAFT ADVISORY FOR THIS AREA
TONIGHT THROUGH TUESDAY. SCATTERED SHOWERS THIS MORNING WILL SHIFT
MAINLY INLAND BY LATE MORNING...BUT WAVES OF SHOWERS AND
THUNDERSTORMS ARE EXPECTED TO PUSH BACK OFFSHORE THIS EVENING AND
OVERNIGHT AS THE COLD FRONT APPROACHES FROM THE WEST.
SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 3 AM MONDAY...WINDS AND SEAS WILL BE CLOSE TO SCA THRESHOLDS
AT THE START OF THE SHORT TERM PERIOD. SW WINDS UP TO 15 TO 20 KTS
WILL PUSH SEAS UP CLOSE TO 5 TO 6 FT IN OUTER WATERS AND 3 TO 4 FT
NEAR SHORE. WILL KEEP WITH SCA FOR NORTHERN 2 MARINE ZONES ONLY
THROUGH THE DAY ON TUES. WINDS WILL VEER AROUND AS COLD FRONT
APPROACHES LATE TUES INTO EARLY WED. THIS WEAKENING OFF SHORE FLOW
AROUND 10 TO 15 KTS WILL ALLOW SEAS TO SUBSIDE DOWN TO 2 TO 4 FT
THROUGH WED.
WINDS AND SEAS WILL INCREASE AGAIN LATE WED INTO THURS AS GRADIENT
TIGHTENS FIRST DUE TO MORE PRONOUNCED PIEDMONT TROUGH INLAND AND
THEN DUE TO APPROACH OF COLD FRONT BY THURS. EXPECT SW WINDS BACK
UP TO A SOLID 15 KTS OR SO BY THURS MORNING WITH SEAS UP AROUND 4
TO 5 FT IN OUTER WATERS.
LONG TERM /THURSDAY THROUGH FRIDAY/...
AS OF 3 AM MONDAY...TIGHTENING GRADIENT FLOW AHEAD OF AN APPROACHING
COLD FRONT WILL PRODUCE SW WINDS UP TO 15 TO 20 KTS. MAY EVEN SEA
WINDS UP CLOSE TO 25 KTS JUST AHEAD OF COLD FRONT LATE THURS NIGHT
INTO EARLY FRI. THIS WILL PUSH SEAS UP TO 6 TO 7 FT IN OUTER
WATERS THURS NIGHT.
BY FRIDAY...THE WINDS WILL VEER AROUND ABRUPTLY TO THE NW-N
BEHIND COLD FRONT AND WILL DIMINISH DOWN TO 10 TO 15 KTS. SEAS
WILL DROP BACK DOWN TO 2 TO 4 FT ON FRI. WINDS WILL CONTINUE TO
VEER AROUND BECOMING MORE ON SHORE BUT LIGHT THROUGH THE WEEKEND AS
HIGH PRESSURE SHIFTS DOWN FROM THE NORTH MOVING CLOSER OVERHEAD
OVER THE WEEKEND.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 8 PM THIS EVENING TO 6 PM EDT
TUESDAY FOR AMZ250-252.
&&
$$
NEAR TERM...TRA
SHORT TERM...RGZ
LONG TERM...RGZ
AVIATION...TRA/BJR
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1252 PM CDT MON JUN 10 2013
.UPDATE...
ISSUED AT 1252 PM CDT MON JUN 10 2013
OTHER THAN MAKING MINOR ADJUSTMENTS TO THE HOURLY SENSIBLE WEATHER
GRIDS...THERE WERE NO MAJOR UPDATES MADE TO THE ONGOING FORECAST.
THE UPDATED GRIDDED AND TEXT PRODUCTS HAVE BEEN SENT.
UPDATE ISSUED AT 1000 AM CDT MON JUN 10 2013
FOG HAS DISSIPATED ACROSS THE JAMES RIVER VALLEY. AS A
RESULT...THE DENSE FOG ADVISORY WAS CANCELLED.
WATER VAPOR IMAGERY NICELY DEPICTS AN UPPER LOW OVER CENTRAL
SASKATCHEWAN THIS MORNING. A JET STREAK ON THE SOUTHERN PERIPHERY
OF THIS FEATURE IS NOSING ITS WAY ACROSS NORTH DAKOTA...AND HAS
SPARKED A FEW THUNDERSTORMS ACROSS NORTHERN NORTH DAKOTA EAST OF
HIGHWAY 83. THE LATEST SHORT RANGE MODEL GUIDANCE PROGS THIS
ACTIVITY TO CONTINUE TO PUSH EAST OF THE CWA AS THE JET STREAK
SHIFTS EAST OF THE REGION.
OTHERWISE...UPDATED TO THE FORECAST TO ADJUST POPS BASED ON
CURRENT RADAR OBS AND HRRR TRENDS. THE UPDATED GRIDDED AND TEXT
PRODUCTS HAVE BEEN SENT.
UPDATE ISSUED AT 630 AM CDT MON JUN 10 2013
MAIN UPDATE WAS TO EXPAND THE COVERAGE OF SHOWERS AND
THUNDERSTORMS THIS MORNING. STRONG UPPER LEVEL JET STREAK COMBINED
WITH SURFACE LOW PRESSURE MOVING FROM WEST TO EAST ACROSS NORTH
DAKOTA PROVIDING PLENTY OF LIFT FOR PRECIPITATION GIVEN RELATIVELY
HIGH BOUNDARY LAYER MOISTURE IN PLACE. A FEW STRONGER
STORMS POPPING UP...HOWEVER MUCAPE AT AROUND 100 J/KG IS LIMITING
THE SEVERE POTENTIAL. A FEW MORE HUNDRED JOULES AND WOULD THINK
SEVERE CRITERIA WOULD EASILY BE MET FOR SOME STORMS GIVEN THE
FORCING IN PLACE.
DENSE FOG ADVISORY SPOT ON...NO CHANGES NEEDED.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 413 AM CDT MON JUN 10 2013
THE MAIN FORECAST CHALLENGE WILL BE DETERMINING THE CHANCES AND
AREAL EXTENT OF EXPECTED SHOWERS AND THUNDERSTORMS FOR TODAY AND
TONIGHT...AND THE DEVELOPING FOG IN THE JAMES RIVER VALLEY.
CURRENTLY...A LOW PRESSURE CENTER WAS OVER EASTERN WYOMING WITH A
TROUGH EXTENDING NORTHEASTWARD ACROSS WESTERN NORTH DAKOTA AND INTO
SOUTHEASTERN SASKATCHEWAN. WEST OF THIS TROUGH WINDS WERE GENERALLY
OUT OF THE NORTH. EAST OF THE TROUGH WINDS WERE SOUTHEASTERLY WITH
PLENTY OF LOW LEVEL MOISTURE. A LARGE AREA OF FOG EXTENDED ACROSS
MUCH OF IOWA AND MINNESOTA...AND HAS SPREAD INTO THE EASTERN
DAKOTAS. DENSE FOG HAD DEVELOPED OVER THE SHEYENNE RIVER VALLEY AND
HAS SPREAD INTO THE JAMES RIVER VALLEY. OAKES REPORTED 1/4 MILE
VISIBILITY...AND JAMESTOWN WAS VARYING BETWEEN 3/4 AND 3 MILES.
EXPECT THAT THE DENSE FOG WILL SPREAD NORTHWARD INTO JAMESTOWN...AND
WILL ISSUE A DENSE FOG ADVISORY FOR FOSTER/STUTSMAN/LAMOURE/LOGAN
COUNTIES - ALONG THE JAMES RIVER VALLEY - UNTIL 10 AM CDT.
AT THE SURFACE...THE AFOREMENTIONED TROUGH OVER WESTERN NORTH DAKOTA
EXTENDED BETWEEN TWO LOW PRESSURE SYSTEMS - ONE OVER CENTRAL
SASKATCHEWAN AND THE OTHER OVER EASTERN WYOMING. AT UPPER LEVELS...A
LARGE LOW WAS STACKED OVER THE SURFACE LOW IN SASKATCHEWAN WITH
SEVERAL VORT ENERGY IMPULSES ROTATING AROUND THE LOW. THE UPPER FLOW
ACROSS NORTH DAKOTA...ON THE SOUTHERN END OF THE UPPER LOW`S
INFLUENCE...WAS WEST-TO-EAST AND ENERGY IMPULSES ARE FORECAST TO
CONTINUE MOVING EASTWARD ACROSS NORTH DAKOTA TODAY.
THE SURFACE TROUGH IS FORECAST TO MOVE EASTWARD ACROSS THE DAKOTAS
TODAY AND REACH THE RED RIVER VALLEY LATER TONIGHT. THIS BOUNDARY
WILL BE THE FOCUS OF SCATTERED SHOWERS AND THUNDERSTORMS ACROSS THE
FORECAST AREA TODAY. SHOWERS AND ISOLATED THUNDERSTORMS THAT
DEVELOPED SUNDAY EVENING CONTINUED THIS MORNING...WITH THE BEST
INSTABILITY OVER THE WYOMING/SOUTH DAKOTA BORDER NEAR THE SURFACE
LOW. HOWEVER THIS MORNING AN INSTABILITY AXIS (OF HIGHER MID LEVEL
LAPSE RATES AND ELEVATED CAPE) EXTENDED FROM THE WY/SD BORDER ACROSS
WESTERN NORTH DAKOTA. THIS COINCIDES WITH THE SURFACE TROUGH AND
CONFIDENT THAT THE BEST CHANCES FOR CONVECTION TODAY WILL BE ALONG
THE TROUGH. THE EASTWARD-MOVING UPPER LEVEL IMPULSES WILL ENHANCE
THE CONVECTION AND HELP MOVE THE SHOWERS EASTWARD.
TONIGHT...THE MODELS INDICATE THE CANADIAN LOW BEGINNING TO LIFT
NORTHEASTWARD...AND KEEPING THE ASSOCIATED UPPER IMPULSES NORTH OF
THE CANADIAN BORDER. HOWEVER...A DEVELOPING UPPER LEVEL TROUGH OVER
THE ROCKIES DAYTIME MONDAY WILL APPROACH THE DAKOTAS TONIGHT AND
BRING INCREASING CHANCES OF THUNDERSTORMS TONIGHT IN SOUTHWESTERN
NORTH DAKOTA.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 413 AM CDT MON JUN 10 2013
MODELS OVERALL IN DECENT AGREEMENT REGARDING THE GENERAL SYNOPTIC
PATTERN FOR THE LONG TERM FORECAST PERIOD. LARGER DIFFERENCES IN THE
DETAILS FOR THE CURRENT 00Z MODEL SUITE COMPARED TO YESTERDAY.
FORECAST HIGHLIGHTS IN THE EXTENDED PERIOD WILL BE CHANCES FOR
SHOWERS/THUNDERSTORMS THROUGH THE WORK WEEK INTO NEXT WEEKEND. WILL
SEE SOME PERIODS OF GREATER PRECIPITATION CHANCES AND
COVERAGE...TUESDAY/TUESDAY NIGHT/WED MORNING AND AGAIN THURSDAY
NIGHT THROUGH FRIDAY AFTERNOON/EVENING.
UPPER LEVEL RIDGE BUILDS EAST ACROSS THE SOUTHERN PLAINS MONDAY
NIGHT WITH LINGERING UPPER LEVEL LOW PRESSURE OVER SOUTH CENTRAL
CANADA. MID LEVEL LOW PRESSURE CURRENTLY OFF THE SOUTHERN CALIFORNIA
COAST IS STILL FORECAST TO EJECT NORTHEAST ACROSS THE ROCKIES AND
INTO THE DAKOTAS...NOW ARRIVING TUESDAY NIGHT/EARLY WEDNESDAY.
EARLIER MODEL RUNS HAD THIS FEATURE ARRIVING 6-12 HOURS FASTER. A
FEW CHANGES TO DISCUSS FOR TUESDAY MORNING/AFTERNOON. THE LAST TWO
RUNS OF THE ECMWF PAINT A BAND OF QPF ACROSS NORTHWEST NORTH DAKOTA
WITH LIGHTER QPF OVER THE REST OF THE CWA. WHILE THE GFS IS
DRY...THE NAM ALSO IS INDICATING PRECIPITATION. DISCOUNTED THE GFS
FOR THIS PARTICULAR PERIOD AS IT APPEARS THERE WILL BE ENOUGH
OVERRUNNING FLOW AND FORCING ALOFT IN THE RIGHT ENTRANCE REGION OF
THE UPPER LEVEL JET TO WARRANT MENTIONING PRECIPITATION. MUCH
DEPENDS ON HOW FAR SOUTH SURFACE HIGH PRESSURE EXTENDS INTO THE
REGION AND HOW FAR WEST AS WELL. THE GFS HAS A SURFACE RIDGE
EXTENDING OVER ALL BUT THE SOUTHWEST...WHILE ECMWF IS A TAD MORE
NORTH. THE SFC HIGH WILL LIMIT THUNDERSTORM CHANCES TUESDAY/TUESDAY
NIGHT TO THE FAR SOUTH WITH LITTLE IF ANY INSTABILITY NORTH OF THE
SD/ND BORDER COUNTIES.
UPPER LEVEL RIDGE REBUILDS ACROSS THE NORTHERN PLAINS WEDNESDAY
DAYTIME...WITH THE RIDGE AXIS PUSHING INTO THE CENTRAL DAKOTAS
WEDNESDAY NIGHT/THURSDAY AHEAD OF A LONG WAVE TROUGH DEVELOPING OVER
THE WEST COAST. SHOWERS ARE EXPECTED TO LINGER MAINLY SOUTH WED
MORNING..WITH ISOLATED CONVECTION POSSIBLE WED AFTERNOON.
MODELS HAVE DIVERGED FROM THEIR EARLIER AGREEMENT WITH SOUTHWEST
FLOW ALOFT DEVELOPING OVER MY WEST. THE ECMWF HAS SLOWED DOWN WITH
THE EASTWARD PROGRESSION OF THE RIDGE AXIS...WITH SOUTHWEST FLOW
DEVELOPING NOT UNTIL THURSDAY DAYTIME. THE GFS STILL MAINTAINS FLOW
ALOFT TRANSITIONING TO SOUTHWEST WED NIGHT. SCALED BACK POPS CENTRAL
WED NIGHT BUT KEPT A MENTION OF NOCTURNAL THUNDERSTORMS WEST.
WEST COAST TROUGH LIFTS INTO THE WYOMING/MONTANA ROCKIES BY 12Z
FRIDAY...THEN EAST-NORTHEAST THROUGH THE NORTHERN PLAINS
FRIDAY-FRIDAY NIGHT. ASSOCIATED SURFACE TROUGH IS STILL FORECAST
TO MOVE INTO WESTERN NORTH DAKOTA 6-12Z FRIDAY MORNING...AND INTO
EASTERN NORTH DAKOTA 00-06Z FRIDAY EVENING. THIS SUGGESTS HIGH
CHANCES AND EXTENSIVE COVERAGE OF THUNDERSTORMS WEST LATE THURSDAY
NIGHT DEVELOPING EAST FRIDAY MORNING/AFTERNOON WITH DECREASING
CHANCES/COVERAGE FROM WEST TO EAST FRIDAY AFTERNOON INTO FRIDAY
EVENING BEHIND THE SFC TROUGH AND UPPER LEVEL WAVE. WILL NEED TO
MONITOR FOR STRONG TO SEVERE POSSIBILITY THIS PERIOD GIVEN THE
FORCING AND INSTABILITY PARAMETERS.
THE ALL-BLEND MODEL CONSENSUS MAINTAINS A SLIGHT CHANCE OF
PRECIPITATION SATURDAY AND SUNDAY...BUT THE WEEKEND DOES NOT APPEAR
TO BE A WASH-OUT.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1252 PM CDT MON JUN 10 2013
VFR CONDITIONS WILL PREVAIL OVER WESTERN AND CENTRAL NORTH DAKOTA
TONIGHT. MVFR VSBYS MAY DEVELOP OVER KJMS BETWEEN 09Z-13Z TUESDAY.
FURTHERMORE...THERE WILL BE A CHANCE OF THUNDERSTORMS OVER
SOUTHWESTERN NORTH DAKOTA (KDIK) AFTER 11Z TUESDAY.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...TM
SHORT TERM...JV
LONG TERM...NH
AVIATION...TM
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1000 AM CDT MON JUN 10 2013
.UPDATE...
ISSUED AT 1000 AM CDT MON JUN 10 2013
FOG HAS DISSIPATED ACROSS THE JAMES RIVER VALLEY. AS A
RESULT...THE DENSE FOG ADVISORY WAS CANCELLED.
WATER VAPOR IMAGERY NICELY DEPICTS AN UPPER LOW OVER CENTRAL
SASKATCHEWAN THIS MORNING. A JET STREAK ON THE SOUTHERN PERIPHERY
OF THIS FEATURE IS NOSING ITS WAY ACROSS NORTH DAKOTA...AND HAS
SPARKED A FEW THUNDERSTORMS ACROSS NORTHERN NORTH DAKOTA EAST OF
HIGHWAY 83. THE LATEST SHORT RANGE MODEL GUIDANCE PROGS THIS
ACTIVITY TO CONTINUE TO PUSH EAST OF THE CWA AS THE JET STREAK
SHIFTS EAST OF THE REGION.
OTHERWISE...UPDATED TO THE FORECAST TO ADJUST POPS BASED ON
CURRENT RADAR OBS AND HRRR TRENDS. THE UPDATED GRIDDED AND TEXT
PRODUCTS HAVE BEEN SENT.
UPDATE ISSUED AT 630 AM CDT MON JUN 10 2013
MAIN UPDATE WAS TO EXPAND THE COVERAGE OF SHOWERS AND
THUNDERSTORMS THIS MORNING. STRONG UPPER LEVEL JET STREAK COMBINED
WITH SURFACE LOW PRESSURE MOVING FROM WEST TO EAST ACROSS NORTH
DAKOTA PROVIDING PLENTY OF LIFT FOR PRECIPITATION GIVEN RELATIVELY
HIGH BOUNDARY LAYER MOISTURE IN PLACE. A FEW STRONGER
STORMS POPPING UP...HOWEVER MUCAPE AT AROUND 100 J/KG IS LIMITING
THE SEVERE POTENTIAL. A FEW MORE HUNDRED JOULES AND WOULD THINK
SEVERE CRITERIA WOULD EASILY BE MET FOR SOME STORMS GIVEN THE
FORCING IN PLACE.
DENSE FOG ADVISORY SPOT ON...NO CHANGES NEEDED.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 413 AM CDT MON JUN 10 2013
THE MAIN FORECAST CHALLENGE WILL BE DETERMINING THE CHANCES AND
AREAL EXTENT OF EXPECTED SHOWERS AND THUNDERSTORMS FOR TODAY AND
TONIGHT...AND THE DEVELOPING FOG IN THE JAMES RIVER VALLEY.
CURRENTLY...A LOW PRESSURE CENTER WAS OVER EASTERN WYOMING WITH A
TROUGH EXTENDING NORTHEASTWARD ACROSS WESTERN NORTH DAKOTA AND INTO
SOUTHEASTERN SASKATCHEWAN. WEST OF THIS TROUGH WINDS WERE GENERALLY
OUT OF THE NORTH. EAST OF THE TROUGH WINDS WERE SOUTHEASTERLY WITH
PLENTY OF LOW LEVEL MOISTURE. A LARGE AREA OF FOG EXTENDED ACROSS
MUCH OF IOWA AND MINNESOTA...AND HAS SPREAD INTO THE EASTERN
DAKOTAS. DENSE FOG HAD DEVELOPED OVER THE SHEYENNE RIVER VALLEY AND
HAS SPREAD INTO THE JAMES RIVER VALLEY. OAKES REPORTED 1/4 MILE
VISIBILITY...AND JAMESTOWN WAS VARYING BETWEEN 3/4 AND 3 MILES.
EXPECT THAT THE DENSE FOG WILL SPREAD NORTHWARD INTO JAMESTOWN...AND
WILL ISSUE A DENSE FOG ADVISORY FOR FOSTER/STUTSMAN/LAMOURE/LOGAN
COUNTIES - ALONG THE JAMES RIVER VALLEY - UNTIL 10 AM CDT.
AT THE SURFACE...THE AFOREMENTIONED TROUGH OVER WESTERN NORTH DAKOTA
EXTENDED BETWEEN TWO LOW PRESSURE SYSTEMS - ONE OVER CENTRAL
SASKATCHEWAN AND THE OTHER OVER EASTERN WYOMING. AT UPPER LEVELS...A
LARGE LOW WAS STACKED OVER THE SURFACE LOW IN SASKATCHEWAN WITH
SEVERAL VORT ENERGY IMPULSES ROTATING AROUND THE LOW. THE UPPER FLOW
ACROSS NORTH DAKOTA...ON THE SOUTHERN END OF THE UPPER LOW`S
INFLUENCE...WAS WEST-TO-EAST AND ENERGY IMPULSES ARE FORECAST TO
CONTINUE MOVING EASTWARD ACROSS NORTH DAKOTA TODAY.
THE SURFACE TROUGH IS FORECAST TO MOVE EASTWARD ACROSS THE DAKOTAS
TODAY AND REACH THE RED RIVER VALLEY LATER TONIGHT. THIS BOUNDARY
WILL BE THE FOCUS OF SCATTERED SHOWERS AND THUNDERSTORMS ACROSS THE
FORECAST AREA TODAY. SHOWERS AND ISOLATED THUNDERSTORMS THAT
DEVELOPED SUNDAY EVENING CONTINUED THIS MORNING...WITH THE BEST
INSTABILITY OVER THE WYOMING/SOUTH DAKOTA BORDER NEAR THE SURFACE
LOW. HOWEVER THIS MORNING AN INSTABILITY AXIS (OF HIGHER MID LEVEL
LAPSE RATES AND ELEVATED CAPE) EXTENDED FROM THE WY/SD BORDER ACROSS
WESTERN NORTH DAKOTA. THIS COINCIDES WITH THE SURFACE TROUGH AND
CONFIDENT THAT THE BEST CHANCES FOR CONVECTION TODAY WILL BE ALONG
THE TROUGH. THE EASTWARD-MOVING UPPER LEVEL IMPULSES WILL ENHANCE
THE CONVECTION AND HELP MOVE THE SHOWERS EASTWARD.
TONIGHT...THE MODELS INDICATE THE CANADIAN LOW BEGINNING TO LIFT
NORTHEASTWARD...AND KEEPING THE ASSOCIATED UPPER IMPULSES NORTH OF
THE CANADIAN BORDER. HOWEVER...A DEVELOPING UPPER LEVEL TROUGH OVER
THE ROCKIES DAYTIME MONDAY WILL APPROACH THE DAKOTAS TONIGHT AND
BRING INCREASING CHANCES OF THUNDERSTORMS TONIGHT IN SOUTHWESTERN
NORTH DAKOTA.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 413 AM CDT MON JUN 10 2013
MODELS OVERALL IN DECENT AGREEMENT REGARDING THE GENERAL SYNOPTIC
PATTERN FOR THE LONG TERM FORECAST PERIOD. LARGER DIFFERENCES IN THE
DETAILS FOR THE CURRENT 00Z MODEL SUITE COMPARED TO YESTERDAY.
FORECAST HIGHLIGHTS IN THE EXTENDED PERIOD WILL BE CHANCES FOR
SHOWERS/THUNDERSTORMS THROUGH THE WORK WEEK INTO NEXT WEEKEND. WILL
SEE SOME PERIODS OF GREATER PRECIPITATION CHANCES AND
COVERAGE...TUESDAY/TUESDAY NIGHT/WED MORNING AND AGAIN THURSDAY
NIGHT THROUGH FRIDAY AFTERNOON/EVENING.
UPPER LEVEL RIDGE BUILDS EAST ACROSS THE SOUTHERN PLAINS MONDAY
NIGHT WITH LINGERING UPPER LEVEL LOW PRESSURE OVER SOUTH CENTRAL
CANADA. MID LEVEL LOW PRESSURE CURRENTLY OFF THE SOUTHERN CALIFORNIA
COAST IS STILL FORECAST TO EJECT NORTHEAST ACROSS THE ROCKIES AND
INTO THE DAKOTAS...NOW ARRIVING TUESDAY NIGHT/EARLY WEDNESDAY.
EARLIER MODEL RUNS HAD THIS FEATURE ARRIVING 6-12 HOURS FASTER. A
FEW CHANGES TO DISCUSS FOR TUESDAY MORNING/AFTERNOON. THE LAST TWO
RUNS OF THE ECMWF PAINT A BAND OF QPF ACROSS NORTHWEST NORTH DAKOTA
WITH LIGHTER QPF OVER THE REST OF THE CWA. WHILE THE GFS IS
DRY...THE NAM ALSO IS INDICATING PRECIPITATION. DISCOUNTED THE GFS
FOR THIS PARTICULAR PERIOD AS IT APPEARS THERE WILL BE ENOUGH
OVERRUNNING FLOW AND FORCING ALOFT IN THE RIGHT ENTRANCE REGION OF
THE UPPER LEVEL JET TO WARRANT MENTIONING PRECIPITATION. MUCH
DEPENDS ON HOW FAR SOUTH SURFACE HIGH PRESSURE EXTENDS INTO THE
REGION AND HOW FAR WEST AS WELL. THE GFS HAS A SURFACE RIDGE
EXTENDING OVER ALL BUT THE SOUTHWEST...WHILE ECMWF IS A TAD MORE
NORTH. THE SFC HIGH WILL LIMIT THUNDERSTORM CHANCES TUESDAY/TUESDAY
NIGHT TO THE FAR SOUTH WITH LITTLE IF ANY INSTABILITY NORTH OF THE
SD/ND BORDER COUNTIES.
UPPER LEVEL RIDGE REBUILDS ACROSS THE NORTHERN PLAINS WEDNESDAY
DAYTIME...WITH THE RIDGE AXIS PUSHING INTO THE CENTRAL DAKOTAS
WEDNESDAY NIGHT/THURSDAY AHEAD OF A LONG WAVE TROUGH DEVELOPING OVER
THE WEST COAST. SHOWERS ARE EXPECTED TO LINGER MAINLY SOUTH WED
MORNING..WITH ISOLATED CONVECTION POSSIBLE WED AFTERNOON.
MODELS HAVE DIVERGED FROM THEIR EARLIER AGREEMENT WITH SOUTHWEST
FLOW ALOFT DEVELOPING OVER MY WEST. THE ECMWF HAS SLOWED DOWN WITH
THE EASTWARD PROGRESSION OF THE RIDGE AXIS...WITH SOUTHWEST FLOW
DEVELOPING NOT UNTIL THURSDAY DAYTIME. THE GFS STILL MAINTAINS FLOW
ALOFT TRANSITIONING TO SOUTHWEST WED NIGHT. SCALED BACK POPS CENTRAL
WED NIGHT BUT KEPT A MENTION OF NOCTURNAL THUNDERSTORMS WEST.
WEST COAST TROUGH LIFTS INTO THE WYOMING/MONTANA ROCKIES BY 12Z
FRIDAY...THEN EAST-NORTHEAST THROUGH THE NORTHERN PLAINS
FRIDAY-FRIDAY NIGHT. ASSOCIATED SURFACE TROUGH IS STILL FORECAST
TO MOVE INTO WESTERN NORTH DAKOTA 6-12Z FRIDAY MORNING...AND INTO
EASTERN NORTH DAKOTA 00-06Z FRIDAY EVENING. THIS SUGGESTS HIGH
CHANCES AND EXTENSIVE COVERAGE OF THUNDERSTORMS WEST LATE THURSDAY
NIGHT DEVELOPING EAST FRIDAY MORNING/AFTERNOON WITH DECREASING
CHANCES/COVERAGE FROM WEST TO EAST FRIDAY AFTERNOON INTO FRIDAY
EVENING BEHIND THE SFC TROUGH AND UPPER LEVEL WAVE. WILL NEED TO
MONITOR FOR STRONG TO SEVERE POSSIBILITY THIS PERIOD GIVEN THE
FORCING AND INSTABILITY PARAMETERS.
THE ALL-BLEND MODEL CONSENSUS MAINTAINS A SLIGHT CHANCE OF
PRECIPITATION SATURDAY AND SUNDAY...BUT THE WEEKEND DOES NOT APPEAR
TO BE A WASH-OUT.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
AT 6 AM CDT...A WEAK FRONTAL BOUNDARY EXTENDED FROM A LOW IN WYOMING
ACROSS WESTERN NORTH DAKOTA AND INTO SASKATCHEWAN. THIS
FEATURE...ALONG WITH UPPER LEVEL ENERGY IMPULSES MOVING FROM WEST TO
EAST ACROSS THE STATE WILL KEEP SHOWERS AND ISOLATED THUNDER AT
KDIK/KMOT/KBIS/KJMS TODAY. THE THREAT OF THUNDER OR RAIN SHOWERS IS
TOO LOW TO MENTION AT KISN. OTHERWISE MAINLY VFR CONDITIONS ARE
EXPECTED TODAY. TONIGHT MVFR AT KDIK AND KJMS MAINLY AFT 06Z.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...TM
SHORT TERM...JV
LONG TERM...NH
AVIATION...JV
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
1038 PM EDT TUE JUN 11 2013
.SYNOPSIS...
WARM HIGH PRESSURE WILL BUILD ACROSS THE REGION WEDNESDAY BEFORE A
COLD FRONT AFFECTS THE AREA ON THURSDAY. DRY HIGH PRESSURE WILL
BUILD IN FROM THE NORTH FRIDAY AND SATURDAY AND KEEP THE WEATHER DRY
OVER MOST OF THE THE WEEKEND. ANOTHER COLD FRONT WILL APPROACH THE
REGION EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH WEDNESDAY/...
AS OF 1030 PM EDT...RADARS REMAIN FAIRLY QUIET UPSTREAM IN THE WEAK
MCS GENESIS REGION ACROSS THE OH VALLEY. HOWEVER...BOTH THE INCOMING
00Z NAM AND THE LATEST HRRR RUN INDICATE CONVECTIVE DEVELOPMENT OVER
SRN OH CIRCA 08Z TO 09Z...AND THIS ACTIVITY COULD WELL MAKE A RUN TO
THE SPINE OF THE SRN APPALACHIANS BEFORE 12Z. WILL THUS CONTINUE TO
FEATURE LOW END CHC POPS ALONG THE TN BORDER STARTING AROUND
DAYBREAK...WITH SCT COVERAGE POSSIBLY SURVIVING INTO THE FOOTHILLS
THROUGH LATE WED MORNING. MODEL PROFILES STILL EXHIBIT QUITE A BIT
OF LOW LEVEL CIN EAST OF THE MTNS...SO WILL KEEP POPS CAPPED AT
SLIGHT CHANCE FOR THE SE HALF THROUGH WED.
LOW LEVEL THICKNESSES SUPPORT MAX TEMPS IN THE MID 90S OVER MUCH OF
THE PIEDMONT WED AFTN. HOWEVER...EXPECT THAT SOME DEBRIS CLOUDS WILL
BE AROUND THROUGH AT LEAST MIDDAY WHICH WILL SLOW DOWN THE WARMING.
EVEN SO...A GUIDANCE BLEND SUPORTS MAX TEMPS IN THE LOW 90S OVER
MUCH OF THE PIEDMONT...WITH MID 80S IN THE MOUNTAIN VALLEYS.
&&
.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY/...
AS OF 245 PM TUESDAY...SHORT RANGE MODELS AGREE THAT THE CENTER OF SFC
LOW PRESSURE WILL TRACK NE ACROSS THE NORTHERN OHIO RIVER VALLEY BY
12Z THURSDAY. AT H5...THE AXIS OF MID LEVEL TROF IS EXPECTED TO
RIPPLE FROM THE OHIO RIVER VALLEY ACROSS THE NC MTNS BY 21Z THURS.
AT THE SFC...A COLD FRONT ASSOCIATED WITH THE NRN LOW PRESSURE WILL
SWEEP ACROSS THE NC MTNS DURING THE EARLY AFTERNOON. THE TIMING OF
THE SFC FRONT AND MID LEVEL WAVE WILL FALL DURING PRIME DIURNAL TIME
FOR DEEP CONVECTION. NAM FORECAST SOUNDINGS ACROSS THE FOOTHILLS AND
PIEDMONT INDICATE THAT CAPE VALUES WILL EXCEED 2000 J/KG...EHI
BETWEEN.5 TO 1 M2/S2...SWEAT GREATER THAN 350. A WEAK BAND OF MAINLY
PRE FRONTAL SHRA MAY REACH THE NC MTNS DURING THE MORNING.
HOWEVER...AS THE LINE MOVE EAST ACROSS THE FOOTHILLS AND
PIEDMONT...CONDITIONS WILL BECOME MORE SUPPORTIVE FOR TSRA
ORGANIZATION INTO A QLCS. THE PRIMARY THREATS WITH THE QLCS WILL BE
DAMAGING STRAIGHT-LINE WINDS AND HAIL...ESPECIALLY ACROSS THE I-77
CORRIDOR. WE WILL CONTINUE TO HIGHLIGHT THE SVR WEATHER THREAT IN
THE HWO.
HIGH TEMPERATURE GUIDANCE ON THURSDAY REMAINS DIVIDED FROM THE VERY
WARM MAV...UPPER 90S...TO THE MET...LOWER TO MID 90S. GIVEN THE
PATTERN OF FALLING LOWER THE MID HEIGHTS...I WILL FAVOR THE MET.
FRIDAY...SHOULD VERIFY AS A FAIR WEATHER DAY AS CANADIAN HIGH
PRESSURE BUILD SOUTH ACROSS THE REGION IN THE WAKE OF THE COLD
FRONT. I WILL FORECAST DRY CONDITIONS WITH LIGHT NORTHEAST WINDS.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
AS OF 115 PM TUESDAY...NO MAJOR CHANGES NEEDED TO THE GOING FCST.
THE MODELS AGREE WELL WITH A BUILDING RIDGE AND LARGE AREA OF DEEP
SUBSIDENCE CONTROLLING THE WX THROUGHOUT THE WEEKEND. AT THE SFC...A
CP HIGH WILL MOVE SOUTH OVER THE REGION SAT/SUN...AND ALONG WITH
RELATIVELY WARM MLVLS...DRY CONDS WITH NEAR SEASONAL TEMPS ARE
EXPECTED. THERE IS SOME DIFFERENCES WRT THE MAGNITUDE AND CHARACTER
OF THE NEXT S/W DEVELOPING OVER THE MIDWEST MON...HOWEVER WILL COUNT
ON A GENERAL INCREASE IN DYNAMICS ALOFT AND HIGHER LLVL MOISTURE
FLUX THROUGH NEW DAY 7. MODEL SOUNDINGS ARE SHOWING GOOD SBSAPE AND
ELCAPE POTENTIAL WITH SOME MODERATE BULK SHEAR...SO THE ENVIRONMENT
WILL BE SET FOR STRONG TO SEVERE CONVECTION DEVELOPING EACH
AFTERNOON MON THROUGH THE PERIOD. MAX TEMPS SHOULD BUMP A COUPLE
DEGREES EACH DAY ONCE SW/LY FLOW BECOMES MAINTAINED SUN NIGHT.
&&
.AVIATION /03Z WEDNESDAY THROUGH SUNDAY/...
AT KCLT...EXPECT GRADUALLY INCREASING HIGH CLOUDS THROUGH WED
MORNING WITH MCS DEBRIS ARRIVING FROM THE NW. WINDS WILL REMAIN
MOSTLY LIGHT NW...BUT WITH AN ADJUSTMENT TO SW THROUGH WED AFTN.
PRECIPITATION CHANCES LOOK QUITE LOW WITH ANY WEAKENING MCS MOVING
THROUGH THE MOUNTAINS GIVEN THE LOW LEVEL CIN IN MODEL PROFILES OVER
THE PIEDMONT WED.
ELSEWHERE...EXPECT MAINLY INCREASING HIGH LEVEL CLOUDS FROM MCS
DEBRIS ARRIVING FROM THE NW TONIGHT THROUGH WED. WILL FEATURE MAINLY
A VCSH MENTION AT KAVL STARTING AT 12Z...WITH PROB30 FOR TSRA AFTER
13Z. CHANCES LOOK TOO SPARSE EAST OF THE MTNS FOR ANY MENTION AT
PRESENT...BUT WEAK ISOLD CONVECTION COULD SURVIVE TO REACH KGSP TO
KHKY THROUGH WED MORNING. ANTICIPATE MAINLY W TO NW FLOW THROUGH THE
PERIOD...EXCEPT FOR WINDS ADJUSTING TO SW AT TIMES IN THE
UPSTATE...ESPECIALLY WED AFTN.
OUTLOOK...A COLD FRONT WILL BRING A GOOD CHANCE OF SHOWERS AND
THUNDERSTORMS TO THE REGION ON THURSDAY. HIGH PRESSURE WILL BUILD IN
BEHIND THE FRONT AND PRODUCE GENERALLY QUIET WEATHER AND VFR
CONDITIONS THROUGH THE WEEKEND.
CONFIDENCE TABLE...
02-08Z 08-14Z 14-20Z 20-02Z
KCLT HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KGSP HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAVL HIGH 100% HIGH 94% HIGH 100% HIGH 100%
KHKY HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KGMU HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAND HIGH 100% HIGH 97% 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...GOODMAN
NEAR TERM...HG
SHORT TERM...NED
LONG TERM...SBK
AVIATION...HG
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
156 AM EDT MON JUN 10 2013
.SYNOPSIS...
MOIST SOUTHERLY FLOW WILL CONTINUE AHEAD OF AN APPROACHING UPPER LOW
PRESSURE TROUGH TONIGHT. THE TROUGH WILL PUSH A COLD FRONT INTO THE
REGION MONDAY NIGHT...FOLLOWED BY HIGH PRESSURE TUESDAY AND
WEDNESDAY. ANOTHER FRONT IS EXPECTED TO MOVE ACROSS THE AREA LATE IN
THE WEEK.
&&
.NEAR TERM /THROUGH TODAY/...
AS OF EARLY MONDAY MORNING...KGSP RADAR SHOWS WIDESPREAD PRECIP
LIFTING N TO NE ACROSS THE FCST AREA. CATEGORICAL POP LOOKS GOOD
INITIALLY...BUT THERE IS A BACK END OF THE PRECIP LIFTING ACROSS THE
SAVANNAH RIVER AS OF 05Z. THIS WILL ALLOW FOR A TEMPORARY LULL...AND
POP WILL BE DECREASED THRU THE EARLY MORNING HOURS...BUT THIS COULD
FILL IN AT ANY TIME.
REMAINDER OF PREVIOUS DISCUSSION...
THE UPPER TROUGH CONTINUES TO SHARPEN UP OVER THE MID MS RIVER
VALLEY. ANTICIPATE IMPROVING AND SLIGHTLY BACKING FLOW ACROSS THE
REGION TO ALLOW CONVECTION TO REGENERATE AND PERHAPS STRENGTHEN
THROUGH THE OVERNIGHT HOURS. A LOW END SEVERE THREAT WILL LINGER
GIVEN THE IMPROVING WIND SHEAR AND EASILY REACHABLE LCL HEIGHTS.
GIVEN THE ROBUST 0 TO 3 KM BULK SHEAR VALUES NOW ADVERTISED ON THE
LATEST RUC RUNS FOR THE OVERNIGHT...HAVE FEATURED AN ISOLD TORNADO
MENTION IN THE HWO.
CONDITIONS ON MONDAY WILL REMAIN FAVORABLE FOR HEAVY RAIN PRODUCING
THUNDERSTORMS...WITH UNSTABLE SOUNDINGS ACROSS THE REGION AS THE
UPPER TROUGH MOVES IN. A SFC COLD FRONT WILL ENTER THE MTNS FROM THE
WEST AROUND MIDDAY. A DRY SLOT AHEAD OF THE FRONT WILL START TO
DIMINISH POPS FROM WEST TO EAST. ONCE AGAIN...DEEP SHEAR CONTINUES
TO INCREASE WITH THE ARRIVAL OF THE TROUGH...SO STORMS AHEAD OF THE
FRONT MAY BE QUITE VIGOROUS...ESPECIALLY IN ERN SECTIONS.
&&
.SHORT TERM /TONIGHT THROUGH WEDNESDAY/...
AS OF 1245 PM SUNDAY...LINGERING DEEP CONVECTIVE CHANCES WILL REMAIN
IN THE FORECAST THRU MONDAY NIGHT SINCE THE 09/12 UTC OP SHORT RANGE
MODELS CONTINUE TO ADVERTISE THE PASSAGE OF A SHARP LOOKING S/WV
TROUGH. WITH THE LATEST NAM RUN NOW IN STEP WITH THE OP GFS IN
TRANSLATING UPPER TROUGH AXIS DOWNSTREAM OF THE CWFA BY TUESDAY
AFTERNOON...WITH PLAN ON SHAVING BACK POP A BIT MORE...ESPECIALLY
GIVING THE PALTRY MOS POPS...FALLING SFC DWPTS AND SOME DOWNSLOPE
FLOW. MAX TEMPERATURES REMAIN SLATED TO REBOUND TO VALUES VERY CLOSE
TO CLIMO.
THE CWFA WILL BE UNDER BROADLY DIFFLUENT WNW FLOW ALOFT TUESDAY
NIGHT INTO WEDNESDAY AND IT IS WITHIN THE REALM OF POSSIBILITY
THAT OHIO VALLEY MCS ACTIVITY WILL MAKE A RUN AT THE NW CWFA BY
WED AM...BUT CONFIDENCE IS STILL NOT HIGH ENUF TO INTRODUCE ANYTHING
AT THIS POINT. UNLESS IT BECOMES OBVIOUS THAT AN IMPULSE/OUTFLOW
IS GOING TO MAKE IT/S WAY ACRS THE CWFA WEDNESDAY WILL PLAN ON
LIMITING DIURNAL TSTM CHANCES TO THE MTNS/LEE TROUGH LOCALES.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
AS OF 1130 AM EDT SUNDAY...A BROAD UPPER RIDGE OF H5 HIGH WILL
REMAIN ANCHORED ACROSS THE SOUTHERN PLAINS...LEAVING OUR FORECAST
AREA UNDER N/NW FLOW ALOFT THROUGH MUCH OF THE MEDIUM RANGE PERIOD.
AT THE SURFACE...A WEAK SURFACE HIGH PRESSURE WILL PREVAIL WED NIGHT
INTO THURSDAY ACROSS THE REGION PROVIDING MOSTLY DRY CONDITIONS. A
COLD FRONT IS EXPECTED TO MOVE ACROSS THE REGION THU NIGHT INTO
EARLY FRI. MODELS AGREE THAT THE FRONT WILL WEAKEN AS IT CROSSES THE
CWA. HENCE...I HAVE CARRIED LOW END CHANCE POPS DURING THIS PERIOD.
CONDITIONS LOOK DRY FOR THE NEXT WEEKEND WITH HIGH PRESSURE BUILDING
ACROSS THE REGION. TEMPS ON THURSDAY WILL BE AROUND 3-5 DEGREES
ABOVE NORMAL WITH HIGHS REACHING THE LOW 90S EAST OF THE MTNS. THEN
TEMPS BACK TO NEAR...OR A FEW DEGREES BELOW NORMAL FRI/SAT BEFORE
WARMING UP TO NEAR NORMAL SUN.
&&
.AVIATION /06Z MONDAY THROUGH FRIDAY/...
AT KCLT AND ELSEWHERE...WIDESPREAD CONVECTION LIFTING N AND NE
ACROSS THE REGION AS OF 06Z...WHICH WILL REQUIRE SOME HANDLING OF
LOWER VISIBILITY IN TEMPO GROUPS. OTHERWISE...A TREND CONTINUES WITH
CLOUD CEILING DROPPING INTO THE IFR CATEGORY AND THINK THAT WILL
PREVAIL FOR MOST OF THE PRE-DAWN HOURS AT ALL TAF SITES...WITH
OCCASIONAL MVFR HOLES THAT WILL NOT BE HANDLED IN A TEMPO AT MOST
SITES. KAVL MIGHT BE THE LAST TO GO COMPLETELY IFR BUT IT SHOULD
HAPPEN BEFORE SUNRISE. THERE COULD BE A LULL IN PRECIP ACROSS THE
REGION AROUND DAYBREAK BUT THERE IS A LINE OF CONVECTION OVER THE TN
VALLEY THAT MAY ARRIVE AFTER SUNSET. THERE IS SOME INDICATION IN THE
MODEL GUIDANCE THAT A LINE OF THUNDERSTORMS WILL MOVE SLOWLY EAST
ACROSS THE REGION DURING THE DAYLIGHT HOURS. SO...AFTER SUNRISE THE
IFR CEILING LIFTS UP TO MVFR AT ALL SITES...BUT THEN A 4 HR TEMPO
FOR THUNDERSTORMS WAS INCLUDED FROM WEST TO EAST BASED ON THE TIMING
OF THE 4KM WRF...WHICH SEEMS REASONABLE. AFTER THAT LINE OF STORMS
MOVES THROUGH...BY LATE AFTERNOON AT KCLT...EXPECT ANOTHER LULL.
THERE COULD BE MORE CONVECTION LATER IN THE EVENING BUT THAT DETAIL
HAD TO BE LEFT OUT OF THE TAFS AT THIS POINT. WIND WILL GENERALLY BE
S TO SW THROUGH THE PERIOD.
OUTLOOK...A COLD FRONT WILL CROSS THE REGION MONDAY NIGHT WITH
CONTINUED SHOWERS AND STORMS...ESPECIALLY IN ERN SECTIONS.
CONDITIONS WILL IMPROVE ON TUE IN THE MIDWEEK AS UPPER LEVEL HIGH
PRESSURE BUILDS IN. THUNDERSTORMS COULD ARRIVE FROM THE NORTHWEST
LATE WED AND AGAIN ON THU.
CONFIDENCE TABLE...
06-12Z 12-18Z 18-24Z 00-06Z
KCLT LOW 59% HIGH 81% MED 76% HIGH 83%
KGSP MED 63% HIGH 91% HIGH 80% HIGH 95%
KAVL HIGH 92% HIGH 82% HIGH 80% MED 75%
KHKY MED 76% HIGH 89% MED 73% HIGH 83%
KGMU HIGH 87% HIGH 93% HIGH 91% HIGH 95%
KAND HIGH 87% HIGH 83% HIGH 93% 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...FLASH FLOOD WATCH THROUGH THIS AFTERNOON FOR GAZ010-017-018-
026-028-029.
NC...FLASH FLOOD WATCH THROUGH THIS AFTERNOON FOR NCZ033-035>037-
048>053-056>059-062>065-068>072-082-501>510.
SC...FLASH FLOOD WATCH THROUGH THIS AFTERNOON FOR SCZ001>014-019.
&&
$$
SYNOPSIS...JOH
NEAR TERM...HG/PM/WIMBERLEY
SHORT TERM...CSH
LONG TERM...JOH
AVIATION...PM
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
1039 PM CDT TUE JUN 11 2013
.UPDATE...
ISSUED AT 929 PM CDT TUE JUN 11 2013
HAVE COORDINATED WITH SPC FOR A BIT OF A TONE DOWN TO THE SEVERE
WEATHER POTENTIAL. ISOLATED ACTIVITY WILL BE A THREAT IN THE NEAR
TERM...WHEN AN ACCAS TSRA DECIDES TO BREAK THROUGH THE CAP. BUT IT
IS CLOSE TO +15C AT 700MB... AND NAM ML CINS CONTINUE TO BE IN THE
300 TO 500 J/KG RANGE FROM ABOUT I 90 SOUTHWARD...RAPIDLY
DECREASING NORTH OF I 90 CREATING QUITE A CIN GRADIENT WHERE MANY
TIMES THUNDERSTORM COMPLEXES WILL TRAVEL. NOTING THAT THE ACTIVITY IN
THE NEBRASKA SAND HILLS HAS ALSO BEEN STRUGGLING SO FAR...NOT REAL
EXCITED ABOUT ANY CONVECTIVE EXPLOSION IN THE NEAR TERM BEFORE
MIDNIGHT NOTING THE CAP STRENGTH. SO ONE WONDERS IF WE WILL HAVE
TO WAIT FOR THE MAIN WAVE WHICH IS ACTIVE IN THE WESTERN PLAINS TO
ENCROACH IN ON OUR AREA...WHICH WOULD BE LATE TONIGHT AND EARLY
WEDNESDAY. WITH LESS CIN IN OUR NORTHERN ZONES...IT IS POSSIBLE
THE ACTIVITY WOULD BE MORE WIDESPREAD IN THOSE AREAS. SO FAR
NOW...BACKED OFF ON THE POPS IN THE EVENING HOURS...BUT STILL HAVE
NUMEROUS STORMS GOING OVER MANY AREAS EXCEPT OUR FAR SOUTHERN
ZONES LATE TONIGHT. OF COURSE...IF THE NEBRASKA SAND HILLS
CONVECTION BEGINS TO LIGHT UP...WILL RAMP UP THE POPS OVER OUR FAR
SOUTHERN ZONES TOO. BUT SO FAR THE NAM AND HRRR HAVE NOT BEEN
HANDLING THE CONVECTION VERY GOOD AND HAVE NOT BEEN GOOD GUIDANCE
TO FOLLOW...PREFERING THE 12Z ECMWF... GEM REGIONAL AND ARW. SO WE
WILL WAIT AND SEE...BUT AGREE SO FAR THAT THE HIGHEST WIND THREAT
MAY BE CONFINED TO OUR WESTERN ZONES GENERALLY FROM MITCHELL
WESTWARD IF THE ACTIVITY HAS TO MOVE IN FROM THE WEST...WITH ISOLATED
STRONG WIND GUSTS OR MICROBURSTS EAST OF MITCHELL. IF THE SEVERE
WEATHER THREAT WAITS UNTIL LATE TONIGHT...THE LARGE HAIL THREAT
WILL LIKELY BE MINIMAL...ALSO NOTING THAT THE ACTIVITY WILL BE
MULTICELLULAR BY THEN.
&&
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 413 PM CDT TUE JUN 11 2013
LINGERING ISOLATED HIGH BASED CONVECTION HAS JUST ABOUT ENDED THIS
AFTERNOON AS EXPECTED. WE WILL AWAIT THE SHORT WAVE AND THE HIGH
PROBABILITY OF STORMS AND EVENTUALLY A SYSTEM ASSOCIATED WITH IT.
WATER VAPOR IMAGERY SHOWS A STRONG UPPER LEVEL WAVE MOVING INTO
SOUTHWESTERN SOUTH DAKOTA. THE 18Z NAM SHOWS MLCIN ON THE ORDER OF
150 J/KG IN THIS AREA SO IT IS GOING TO TAKE A PERIOD OF LIFT WITHIN
THE CAP TO GET THUNDERSTORMS TO DEVELOP. THEREFORE NOT REALLY
EXPECTING THESE STORMS TO DEVELOP UNTIL CLOSER TO 00Z. THERE IS
AMPLE BULK SHEAR...AROUND 50 KTS IN THE 0 TO 6 KM LAYER...TO HELP
STORMS RAPIDLY ORGANIZE ONCE THEY DEVELOP.
THE QUESTION THEN BECOMES IF THE STORMS CAN BE MAINTAINED AS THE SUN
SETS AND SURFACE HEATING IS LOST. AT THIS POINT...IT APPEARS THE
STORMS SHOULD BE ABLE TO BE MAINTAINED DUE TO THE STRONG UPPER LEVEL
WAVE ENHANCING LIFT AHEAD OF THE LINE OF STORMS AND ACTING TO WEAKEN
THE CAP ENOUGH THAT SOME OF THE BOUNDARY LAYER AIR CAN BE UTILIZED
TO KEEP ROBUST UPDRAFTS DUE TO CAPES OVER 1000 J/KG. IN
ADDITION...IF THE STORMS ORGANIZE AND BEGIN TO GROW UPSCALE THEN
INTERNAL STORM DYNAMICS CAN HELP OVERCOME BOUNDARY LAYER
INHIBITION... SO A WELL ORGANIZED MCS SHOULD BE ABLE TO PROPAGATE
INTO EASTERN SOUTH DAKOTA. CURRENT HIGH RES MODELS...SUCH AS THE
HRRR...HAVE THESE STORMS IN THE VICINITY OF I90 IN WRN SD AFTER
DARK. FORWARD PROPAGATING CORFIDI VECTORS WOULD SUPPORT AN MCS
MOTION JUST NORTH OF EAST. THIS WOULD TAKE THE STORMS PRIMARILY
NORTH OF I90. AT THIS POINT...THIS APPEARS TO BE WHERE THE GREATEST
THREAT FOR SEVERE WEATHER WILL BE. ADDITIONAL DEVELOPMENT SOUTH OF
I90 IS POSSIBLE ON THE SOUTH SIDE OF THE SYSTEM. BUT WITH A STRONG
CAP...STORM MAY NOT EXTEND TOO FAR SOUTH OF I90. AS THE STORMS MOVE
EAST INTO MINNESOTA AND IOWA...THE INCREASING STABILITY LIKELY TO
WEAKEN CONVECTION OVERTIME AND DECREASE THE SEVERE THREAT AFTER 09Z.
AT THIS POINT...DAMAGING WINDS APPEAR TO BE THE GREATEST THREAT FOR
SEVERE WEATHER AS STORMS WILL LIKELY BE ORGANIZED INTO AN MCS BY THE
TIME THEY REACH THE MISSOURI RIVER. EXPECTATION IS STORMS WILL MOVE
TOWARD CHAMBERLAIN BETWEEN 04Z AND 08Z AND REACH I29 SOMETIME
BETWEEN 07Z AND 09Z. A FEW STORMS COULD PRODUCE QUARTER TO GOLF
BALLS SIZE HAIL OVERNIGHT ESPECIALLY ON THE SOUTH SIDE OF THE
COMPLEX WHERE NEW UPDRAFTS ARE MOST LIKELY AND CAN TAKE ADVANTAGE OF
LARGE CAPE IN THE HAIL PRODUCING LAYER...BUT THIS SHOULD NOT BE
WIDESPREAD AND IS A LOWER THREAT THAN WINDS.
WITH THE STRONG SOUTHERLY FLOW AND WINDS AND CLOUDS...LOWS WILL
REMAIN INTHE 60S OVERNIGHT WITH THE POSSIBILITY OF ONLY FALLING TO
70 DEGREES AROUND SIOUX CITY. THE AREA OF RAIN AND THUNDERSTORMS
WILL MOVE EAST OF THE AREA
THIS SYSTEM MAY PRESENT SOME TRAILING CELLS WEDNESDAY MORNING...BUT
AS A WHOLE...SHOULD STEADILY MOVE EAST OF OUR AREA GIVEN THE WELL
DEFINED NATURE OF THE WAVE. CLOUDS SHOULD DECREASE FROM THE
WEST/SOUTHWEST IN THE LATE MORNING AND AFTERNOON. A COOLER REGIME
WEDNESDAY SHOULD BRING HIGHS INT HE 70S TO LOWER 80S...WHICH ALLOWS
FOR SOME HEATING AS THE SYSTEM MOVES OUT AND LEAVES OUR AREA IN
COOLER AIR.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 413 PM CDT TUE JUN 11 2013
SHOULD SEE DECREASING CLOUDS WEDNESDAY NIGHT AND LIGHT WINDS...WITH
LARGE SCALE SUBSIDENCE BEHIND THE STRONG WAVE. LOWS WILL BE A BIT
COOLER...MAINLY IN THE 50S. MOSTLY SUNNY SKIES EXPECTED ON THURSDAY
WITH HIGHS AROUND AVERAGE FOR THIS TIME OF YEAR...UPPER 70S TO LOW
80S. BY THURSDAY NIGHT...LOW LEVEL JET AND THETAE ADVECTION BEGINS
TO INCREASE OVER THE REGION. THUS EXPECTING AN INCREASE IN MID LEVEL
CLOUDS WITH THE THREAT OF ISOLATED TO SCATTERED ELEVATED CONVECTION
THURSDAY NIGHT INTO FRIDAY. CURRENTLY THINKING SEVERE THREAT REMAINS
LOW WITH THE BEST INSTABILITY EXPECTED TO STAY TO OUR SOUTHWEST. BUT
WITH WIND FIELDS REMAINING UP...COULD SEE A FEW MARGINAL SEVERE
STORMS. A BETTER UPPER WAVE SHOULD ENTER THE NORTHERN PLAINS LATER
FRIDAY AFTERNOON INTO FRIDAY NIGHT. WITH CAPPING IN PLACE SURFACE
BASED CONVECTION DOES NOT SEEM LIKELY. BUT WITH CONTINUED LOW AND
MID LEVEL ISENTROPIC LIFT AND BETTER UPPER SUPPORT...THINKING IS WE
SEE AN INCREASE IN COVERAGE OF ELEVATED SHOWERS AND THUNDERSTORMS.
WITH HIGHER MUCAPE UP TO 2000 J/KG MAY SEE A SLIGHTLY BETTER CHANCE
OF SEVERE WEATHER FRIDAY NIGHT INTO SATURDAY MORNING. ALTHOUGH EVEN
THIS THREAT SEEMS PRETTY MARGINAL AND MAY END UP ACROSS OUR EASTERN
HALF OR EVEN EAST OF OUR CWA.
THE MORE ACTIVE PATTERN SHOULD END UP CONTINUING INTO THE WEEKEND
WITH HIGHS REMAINING NEAR OR JUST ABOVE AVERAGE...UPPER 70S TO MID
80S. CAP IS WEAKER ON SATURDAY WITH CAPE AROUND 2000 J/KG EXPECTED.
DRY AIR DOES WORK ITS WAY INTO THE AREA THOUGH...WHICH COMBINED WITH
THE WEAK CAP MAY PREVENT SURFACE BASED CONVECTION FROM
FORMING...ESPECIALLY WITHOUT A STRONG FORCING MECHANISM. WITH THAT
SAID WILL HAVE TO MONITOR AS IF SOMETHING CAN FORM...WIND FIELDS
SUGGEST A SUPERCELL POTENTIAL WITH LARGE HAIL AND STRONG WINDS.
LARGE SCALE FORCING INCREASES FOR SUNDAY WITH A WAVE PASSING TO OUR
NORTH. EC IS MUCH STRONGER WITH THIS WAVE AND WOULD SUGGEST A HIGHER
SEVERE THREAT. TIMING STILL UNCERTAIN ON THIS WAVE...SO TOUGH TO SAY
WHETHER BEST SHOT IS DURING THE AFTERNOON OR OVERNIGHT.
WENT DRY EARLY NEXT WEEK AS RIDGING BUILDS BACK INTO THE AREA. CANT
COMPLETELY RULE OUT AN ISOLATED SHOWER OR STORM...BUT THREAT SEEMS
TOO LOW TO MENTION IN THE FORECAST AT THIS TIME. GENERALLY EXPECTING
PARTLY TO MOSTLY SUNNY SKIES WITH HIGHS CONTINUING TO RUN WITHIN A
FEW DEGREES OF AVERAGE...MAYBE A BIT COOLER DEPENDING ON STRENGTH OF
THE WAVE SUNDAY INTO SUNDAY NIGHT.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1039 PM CDT TUE JUN 11 2013
VFR CONDITIONS WITH GUSTY EAST WINDS AND ISOLATED TSTMS THIS LATE
EVENING WILL GIVE WAY TO THUNDERSTORM COMPLEXES MOVING WSW TO ENE
ACROSS THE AREA FROM AROUND MIDNIGHT THROUGH EARLY WEDNESDAY
MORNING. THESE THUNDERSTORMS COMPLEXES ARE EXPECTED TO BE STRONG
TO SEVERE WITH THE MAIN THREAT BEING STRONG/DAMAGING
WINDS...MAINLY ON THE LEADING EDGE OF THE COMPLEXES. LARGE HAIL
WILL ALSO BE A POSSIBILITY. BEHIND THE DEPARTING THUNDERSTORM
COMPLEXES...VFR CONDITIONS WILL RESUME BY WEDNESDAY MID
MORNING...HOWEVER NORTH WINDS WILL BE GUSTY.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
UPDATE...MJF
SHORT TERM...SCHUMACHER
LONG TERM...CHENARD
AVIATION...
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
1250 PM CDT MON JUN 10 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 346 AM CDT MON JUN 10 2013
CLEAR SKIES/LIGHT WINDS AND RESIDUAL BOUNDARY LAYER MOISTURE FROM
RECENT RAINS ALLOWING DENSE FOG TO DEVELOP IN WESTERN/CENTRAL PARTS
OF THE CWA EARLY THIS MORNING. HRRR HAS LATCHED ONTO EXPANSION OF
THE LOWEST VISIBILITIES WHICH HAS OCCURRED OVER THE PAST HOUR OR
SO...AND IT SHOWS POTENTIAL FOR DENSE FOG PERSISTING IN THE SURFACE
RIDGE AXIS THROUGH ABOUT 13-14Z WITH RAPID IMPROVEMENT THEREAFTER.
ISSUED DENSE FOG ADVISORY DUE TO EXPECTED PERSISTENCE...THOUGH MAY
STILL BE A BIT PATCHY IN SPOTS...ESPECIALLY THE FAR WEST WHERE THE
WIND MAY PICK UP A BIT AS THE RIDGE SHIFTS EAST. STRATUS AND A BIT
MORE WIND EAST OF THE RIDGE AXIS HAS HELPED TO HOLD VISIBILITY UP
ACROSS NORTHWEST IOWA AND PARTS OF SOUTHWEST MN THUS FAR...SO DID
NOT INCLUDE THEM IN THE ADVISORY AT THIS TIME...THOUGH WILL WATCH
FOR DOWNWARD TREND SHOULD THE STRATUS CLEAR. SEEING SOME ACCAS
STREAMING TOWARD FAR WESTERN COUNTIES EARLY THIS MORNING AS WELL.
SOUTHERN EDGE HAS SHOWN TENDENCY TO DISSIPATE AS IT SHIFTS EAST...
AND 06Z NAM INDICATES THIS TREND AS WELL...KEEPING BULK OF HIGHER
MID LEVEL MOISTURE NORTH OF OUR CWA THROUGH THE MORNING. DID BRING
IN A LITTLE HIGHER SKY COVER TO OUR NORTHWEST EARLY...BUT THINK MOST
OF THE DAY SHOULD SEE FAIR AMOUNT OF SUNSHINE. THUS AFTER THE FOG
BURNS OFF...EXPECT TEMPERATURES TO REBOUND NICELY...THOUGH PERHAPS A
BIT MORE SLOWLY IN THE EAST WHERE STRATUS MAY LINGER INTO THE MID TO
LATER MORNING HOURS. WITH 925MB TEMPERATURES FORECAST TO RISE INTO
THE 20S C BY 11/00Z...HIGHS FROM THE UPPER 70S EAST TO THE MID-UPPER
80S SOUTHWEST LOOK GOOD.
MID LEVEL CLOUDS WILL BE ON THE INCREASE MONDAY NIGHT AS ATMOSPHERE
ABOVE 600 MB SATURATE IN RESPONSE TO INCREASE IN THETAE ADVECTION.
WHILE SHORTWAVE IS EXPECTED TO MOVE ACROSS THE FORECAST
AREA...APPEARS AS THOUGH ATMOSPHERE WILL REMAIN EFFECTIVELY CAPPED
LIMITING THUNDERSTORM POTENTIAL TO FAR WESTERN PORTIONS OF CWA IN
CENTRAL SOUTH DAKOTA.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 346 AM CDT MON JUN 10 2013
THE OUTSIDE CHANCE OF AN ELEVATED STORMS WILL CONTINUE THROUGH
TUESDAY MORNING...BUT EXPECT CHANCES TO DWINDLE THROUGHOUT THE DAY
ON TUESDAY. FORECAST AREA REMAINS IN EASTERLY FLOW THROUGHOUT THE
DAY ON TUESDAY AS WARM FRONT LIFTS NORTH TOWARDS THE CWA. TOUGH CALL
ON CONVECTION CHANCES TUESDAY NIGHT WITH STRONG MID LEVEL CAP
PRESENT. MODELS HIND THAT CAP MAY TRY TO WEAKEN...AND THE BEST
CHANCE FOR THUNDERSTORMS REMAINS ACROSS THE NORTHERN FRINGE OF THE
FORECAST AREA. IF STORMS ARE ABLE TO DEVELOP...THEY WOULD LIKELY
QUICKLY BECOME SEVERE PRODUCING SEVERE HAIL WITH STRONG MID LEVEL
LAPSE RATES.
HAVE LEFT LINGERING POPS INTO WEDNESDAY...THOUGH THERE IS REALLY A
LACK OF ANY LARGE SCALE FOCUSING MECHANISM WITH SURFACE HIGH
PRESSURE BUILDING IN FROM THE NORTH. AS SUCH...JUST HAVE A GENERAL
20-40 CHANCE WHICH WILL BE VERY DEPENDENT ON WHAT HAPPENS TUESDAY
NIGHT.
THURSDAY INTO THE BETTER PORTION OF FRIDAY SHOULD BE RELATIVELY
DRY. THE EXCEPTION TO THIS WOULD BE LATE ON THURSDAY NIGHT AS WARM
AIR ADVECTION INCREASES UNDER SOUTHERLY FLOW AND COULD SEE ACCAS
SHOWERS.
POTENTIAL FOR DEEP CONVECTION FRIDAY NIGHT CONTINUES TO INCREASE AS
UPPER LEVEL LOW PRESSURE SYSTEM LIFTS NORTHEAST INTO CENTRAL CANADA
AND TRAILING COLD FRONT MOVES ACROSS THE FORECAST AREA. WHAT
CONTINUES TO BE IMPRESSIVE ABOUT THIS SET UP ARE THE VERY STEEP
LAPSE RATE FROM 700-400 MB AND SPEED SHEAR ALOFT INDICATING THE
POTENTIAL FOR VERY LARGE HAIL IF THUNDERSTORMS ARE ABLE TO DEVELOP.
THE UNSETTLED PATTERN CONTINUES INTO THE WEEKEND AS UPPER LEVEL LOW
RE-ESTABLISHES ITSELF OFF THE PACIFIC NW COAST. PIECES OF ENERGY
PERIODICALLY BREAK OFF THE UPPER LEVEL LOW EJECTING INTO THE
PLAINS. AT THIS POINT...IT CONTINUES TO BE DIFFICULT TO PINPOINT
PRECISE TIMING OF DEEP CONVECTION...BUT HAVE STARTED TO TWEAK
DAYTIME POPS DOWN AND NOCTURNAL POPS UP TO HELP ACCOUNT FOR TYPICAL
DIURNAL PATTERN THIS TIME OF YEAR.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1245 PM CDT MON JUN 10 2013
MVFR CIGS LINGERING ACROSS PORTIONS OF NORTHWEST IOWA AND SOUTHWEST
MINNESOTA...WITH VFR CONDITIONS ELSEWHERE. CONDITIONS SHOULD BECOME
VFR EVERYWHERE BY MID AFTERNOON. SOME INDICATIONS THAT SOME SHOWER
AND THUNDERSTORM ACTIVITY COULD DEVELOP OVER THE WESTERN PLAINS THIS
AFTERNOON AND EVENING AND MOVE TOWARDS US TONIGHT. THUS COULD SEE SOME
HIGH BASED SHOWER OR THUNDERSTORM ACTIVITY AFTER MIDNIGHT INTO THE
MORNING HOURS...BUT CONFIDENCE AND EXPECTED COVERAGE ARE BOTH TOO
LOW TO MENTION IN THE TAFS AT THIS TIME. MOS GUIDANCE SUGGESTS WE
COULD SEE SOME FOG TONIGHT....BUT THINK THE INCREASING MID LEVEL
CLOUD COVER AND A LIGHT BREEZE WILL PROBABLY PREVENT THAT FROM
HAPPENING...SO WILL LEAVE THAT OUT OF THE TAFS FOR NOW AS WELL.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
SHORT TERM...JH
LONG TERM...
AVIATION...CHENARD
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
700 AM CDT MON JUN 10 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 346 AM CDT MON JUN 10 2013
CLEAR SKIES/LIGHT WINDS AND RESIDUAL BOUNDARY LAYER MOISTURE FROM
RECENT RAINS ALLOWING DENSE FOG TO DEVELOP IN WESTERN/CENTRAL PARTS
OF THE CWA EARLY THIS MORNING. HRRR HAS LATCHED ONTO EXPANSION OF
THE LOWEST VISIBILITIES WHICH HAS OCCURRED OVER THE PAST HOUR OR
SO...AND IT SHOWS POTENTIAL FOR DENSE FOG PERSISTING IN THE SURFACE
RIDGE AXIS THROUGH ABOUT 13-14Z WITH RAPID IMPROVEMENT THEREAFTER.
ISSUED DENSE FOG ADVISORY DUE TO EXPECTED PERSISTENCE...THOUGH MAY
STILL BE A BIT PATCHY IN SPOTS...ESPECIALLY THE FAR WEST WHERE THE
WIND MAY PICK UP A BIT AS THE RIDGE SHIFTS EAST. STRATUS AND A BIT
MORE WIND EAST OF THE RIDGE AXIS HAS HELPED TO HOLD VISIBILITY UP
ACROSS NORTHWEST IOWA AND PARTS OF SOUTHWEST MN THUS FAR...SO DID
NOT INCLUDE THEM IN THE ADVISORY AT THIS TIME...THOUGH WILL WATCH
FOR DOWNWARD TREND SHOULD THE STRATUS CLEAR. SEEING SOME ACCAS
STREAMING TOWARD FAR WESTERN COUNTIES EARLY THIS MORNING AS WELL.
SOUTHERN EDGE HAS SHOWN TENDENCY TO DISSIPATE AS IT SHIFTS EAST...
AND 06Z NAM INDICATES THIS TREND AS WELL...KEEPING BULK OF HIGHER
MID LEVEL MOISTURE NORTH OF OUR CWA THROUGH THE MORNING. DID BRING
IN A LITTLE HIGHER SKY COVER TO OUR NORTHWEST EARLY...BUT THINK MOST
OF THE DAY SHOULD SEE FAIR AMOUNT OF SUNSHINE. THUS AFTER THE FOG
BURNS OFF...EXPECT TEMPERATURES TO REBOUND NICELY...THOUGH PERHAPS A
BIT MORE SLOWLY IN THE EAST WHERE STRATUS MAY LINGER INTO THE MID TO
LATER MORNING HOURS. WITH 925MB TEMPERATURES FORECAST TO RISE INTO
THE 20S C BY 11/00Z...HIGHS FROM THE UPPER 70S EAST TO THE MID-UPPER
80S SOUTHWEST LOOK GOOD.
MID LEVEL CLOUDS WILL BE ON THE INCREASE MONDAY NIGHT AS ATMOSPHERE
ABOVE 600 MB SATURATE IN RESPONSE TO INCREASE IN THETAE ADVECTION.
WHILE SHORTWAVE IS EXPECTED TO MOVE ACROSS THE FORECAST
AREA...APPEARS AS THOUGH ATMOSPHERE WILL REMAIN EFFECTIVELY CAPPED
LIMITING THUNDERSTORM POTENTIAL TO FAR WESTERN PORTIONS OF CWA IN
CENTRAL SOUTH DAKOTA.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 346 AM CDT MON JUN 10 2013
THE OUTSIDE CHANCE OF AN ELEVATED STORMS WILL CONTINUE THROUGH
TUESDAY MORNING...BUT EXPECT CHANCES TO DWINDLE THROUGHOUT THE DAY
ON TUESDAY. FORECAST AREA REMAINS IN EASTERLY FLOW THROUGHOUT THE
DAY ON TUESDAY AS WARM FRONT LIFTS NORTH TOWARDS THE CWA. TOUGH CALL
ON CONVECTION CHANCES TUESDAY NIGHT WITH STRONG MID LEVEL CAP
PRESENT. MODELS HIND THAT CAP MAY TRY TO WEAKEN...AND THE BEST
CHANCE FOR THUNDERSTORMS REMAINS ACROSS THE NORTHERN FRINGE OF THE
FORECAST AREA. IF STORMS ARE ABLE TO DEVELOP...THEY WOULD LIKELY
QUICKLY BECOME SEVERE PRODUCING SEVERE HAIL WITH STRONG MID LEVEL
LAPSE RATES.
HAVE LEFT LINGERING POPS INTO WEDNESDAY...THOUGH THERE IS REALLY A
LACK OF ANY LARGE SCALE FOCUSING MECHANISM WITH SURFACE HIGH
PRESSURE BUILDING IN FROM THE NORTH. AS SUCH...JUST HAVE A GENERAL
20-40 CHANCE WHICH WILL BE VERY DEPENDENT ON WHAT HAPPENS TUESDAY
NIGHT.
THURSDAY INTO THE BETTER PORTION OF FRIDAY SHOULD BE RELATIVELY
DRY. THE EXCEPTION TO THIS WOULD BE LATE ON THURSDAY NIGHT AS WARM
AIR ADVECTION INCREASES UNDER SOUTHERLY FLOW AND COULD SEE ACCAS
SHOWERS.
POTENTIAL FOR DEEP CONVECTION FRIDAY NIGHT CONTINUES TO INCREASE AS
UPPER LEVEL LOW PRESSURE SYSTEM LIFTS NORTHEAST INTO CENTRAL CANADA
AND TRAILING COLD FRONT MOVES ACROSS THE FORECAST AREA. WHAT
CONTINUES TO BE IMPRESSIVE ABOUT THIS SET UP ARE THE VERY STEEP
LAPSE RATE FROM 700-400 MB AND SPEED SHEAR ALOFT INDICATING THE
POTENTIAL FOR VERY LARGE HAIL IF THUNDERSTORMS ARE ABLE TO DEVELOP.
THE UNSETTLED PATTERN CONTINUES INTO THE WEEKEND AS UPPER LEVEL LOW
RE-ESTABLISHES ITSELF OFF THE PACIFIC NW COAST. PIECES OF ENERGY
PERIODICALLY BREAK OFF THE UPPER LEVEL LOW EJECTING INTO THE
PLAINS. AT THIS POINT...IT CONTINUES TO BE DIFFICULT TO PINPOINT
PRECISE TIMING OF DEEP CONVECTION...BUT HAVE STARTED TO TWEAK
DAYTIME POPS DOWN AND NOCTURNAL POPS UP TO HELP ACCOUNT FOR TYPICAL
DIURNAL PATTERN THIS TIME OF YEAR.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 700 AM CDT MON JUN 10 2013
LIFR CONDITIONS FAIRLY WIDESPREAD ACROSS THE AREA AT THE START OF THE
PERIOD...EITHER WITH SUB 1SM VISIBILITY IN FG OR CEILINGS AT OR BELOW
400FT AGL IN STRATUS. EXPECT CONDITIONS TO IMPROVE AFTER 14Z...THOUGH
CEILINGS NEAR/EAST OF I-29 CORRIDOR MAY BE SLOWER TO IMPROVE THAN
VISIBILITY. VFR CONDITIONS EXPECTED ACROSS THE FORECAST AREA BY 17Z-
18Z. REMOTE CHANCE OF ISOLATED HIGH BASED SHRA/TSRA WEST OF I-29 LATE
IN THE FORECAST PERIOD...BUT CHANCE TOO SMALL TO MENTION IN KHON TAF.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...DENSE FOG ADVISORY UNTIL 9 AM CDT THIS MORNING FOR SDZ038>040-
053>056-059>062-065>071.
MN...DENSE FOG ADVISORY UNTIL 9 AM CDT THIS MORNING FOR MNZ071-072-
080-097-098.
IA...NONE.
NE...DENSE FOG ADVISORY UNTIL 9 AM CDT THIS MORNING FOR NEZ013-014.
&&
$$
SHORT TERM...JH
LONG TERM...
AVIATION...JH
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
348 AM CDT MON JUN 10 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 346 AM CDT MON JUN 10 2013
CLEAR SKIES/LIGHT WINDS AND RESIDUAL BOUNDARY LAYER MOISTURE FROM
RECENT RAINS ALLOWING DENSE FOG TO DEVELOP IN WESTERN/CENTRAL PARTS
OF THE CWA EARLY THIS MORNING. HRRR HAS LATCHED ONTO EXPANSION OF
THE LOWEST VISIBILITIES WHICH HAS OCCURRED OVER THE PAST HOUR OR
SO...AND IT SHOWS POTENTIAL FOR DENSE FOG PERSISTING IN THE SURFACE
RIDGE AXIS THROUGH ABOUT 13-14Z WITH RAPID IMPROVEMENT THEREAFTER.
ISSUED DENSE FOG ADVISORY DUE TO EXPECTED PERSISTENCE...THOUGH MAY
STILL BE A BIT PATCHY IN SPOTS...ESPECIALLY THE FAR WEST WHERE THE
WIND MAY PICK UP A BIT AS THE RIDGE SHIFTS EAST. STRATUS AND A BIT
MORE WIND EAST OF THE RIDGE AXIS HAS HELPED TO HOLD VISIBILITY UP
ACROSS NORTHWEST IOWA AND PARTS OF SOUTHWEST MN THUS FAR...SO DID
NOT INCLUDE THEM IN THE ADVISORY AT THIS TIME...THOUGH WILL WATCH
FOR DOWNWARD TREND SHOULD THE STRATUS CLEAR. SEEING SOME ACCAS
STREAMING TOWARD FAR WESTERN COUNTIES EARLY THIS MORNING AS WELL.
SOUTHERN EDGE HAS SHOWN TENDENCY TO DISSIPATE AS IT SHIFTS EAST...
AND 06Z NAM INDICATES THIS TREND AS WELL...KEEPING BULK OF HIGHER
MID LEVEL MOISTURE NORTH OF OUR CWA THROUGH THE MORNING. DID BRING
IN A LITTLE HIGHER SKY COVER TO OUR NORTHWEST EARLY...BUT THINK MOST
OF THE DAY SHOULD SEE FAIR AMOUNT OF SUNSHINE. THUS AFTER THE FOG
BURNS OFF...EXPECT TEMPERATURES TO REBOUND NICELY...THOUGH PERHAPS A
BIT MORE SLOWLY IN THE EAST WHERE STRATUS MAY LINGER INTO THE MID TO
LATER MORNING HOURS. WITH 925MB TEMPERATURES FORECAST TO RISE INTO
THE 20S C BY 11/00Z...HIGHS FROM THE UPPER 70S EAST TO THE MID-UPPER
80S SOUTHWEST LOOK GOOD.
MID LEVEL CLOUDS WILL BE ON THE INCREASE MONDAY NIGHT AS ATMOSPHERE
ABOVE 600 MB SATURATE IN RESPONSE TO INCREASE IN THETAE ADVECTION.
WHILE SHORTWAVE IS EXPECTED TO MOVE ACROSS THE FORECAST
AREA...APPEARS AS THOUGH ATMOSPHERE WILL REMAIN EFFECTIVELY CAPPED
LIMITING THUNDERSTORM POTENTIAL TO FAR WESTERN PORTIONS OF CWA IN
CENTRAL SOUTH DAKOTA. THE OUTSIDE CHANCE OF AN ELEVATED STORMS WILL
CONTINUE THROUGH TUESDAY MORNING...BUT EXPECT CHANCES TO DWINDLE
THROUGHOUT THE DAY ON TUESDAY. FORECAST AREA REMAINS IN EASTERLY
FLOW THROUGHOUT THE DAY ON TUESDAY AS WARM FRONT LIFTS NORTH TOWARDS
THE CWA. TOUGH CALL ON CONVECTION CHANCES TUESDAY NIGHT WITH STRONG
MID LEVEL CAP PRESENT. MODELS HIND THAT CAP MAY TRY TO WEAKEN...AND
THE BEST CHANCE FOR THUNDERSTORMS REMAINS ACROSS THE NORTHERN FRINGE
OF THE FORECAST AREA. IF STORMS ARE ABLE TO DEVELOP...THEY WOULD
LIKELY QUICKLY BECOME SEVERE PRODUCING SEVERE HAIL WITH STRONG MID
LEVEL LAPSE RATES.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 346 AM CDT MON JUN 10 2013
HAVE LEFT LINGERING POPS INTO WEDNESDAY...THOUGH THERE IS REALLY A
LACK OF ANY LARGE SCALE FOCUSING MECHANISM WITH SURFACE HIGH
PRESSURE BUILDING IN FROM THE NORTH. AS SUCH...JUST HAVE A GENERAL
20-40 CHANCE WHICH WILL BE VERY DEPENDENT ON WHAT HAPPENS TUESDAY
NIGHT.
THURSDAY INTO THE BETTER PORTION OF FRIDAY SHOULD BE RELATIVELY
DRY. THE EXCEPTION TO THIS WOULD BE LATE ON THURSDAY NIGHT AS WARM
AIR ADVECTION INCREASES UNDER SOUTHERLY FLOW AND COULD SEE ACCAS
SHOWERS.
POTENTIAL FOR DEEP CONVECTION FRIDAY NIGHT CONTINUES TO INCREASE AS
UPPER LEVEL LOW PRESSURE SYSTEM LIFTS NORTHEAST INTO CENTRAL CANADA
AND TRAILING COLD FRONT MOVES ACROSS THE FORECAST AREA. WHAT
CONTINUES TO BE IMPRESSIVE ABOUT THIS SET UP ARE THE VERY STEEP
LAPSE RATE FROM 700-400 MB AND SPEED SHEAR ALOFT INDICATING THE
POTENTIAL FOR VERY LARGE HAIL IF THUNDERSTORMS ARE ABLE TO DEVELOP.
THE UNSETTLED PATTERN CONTINUES INTO THE WEEKEND AS UPPER LEVEL LOW
RE-ESTABLISHES ITSELF OFF THE PACIFIC NW COAST. PIECES OF ENERGY
PERIODICALLY BREAK OFF THE UPPER LEVEL LOW EJECTING INTO THE
PLAINS. AT THIS POINT...IT CONTINUES TO BE DIFFICULT TO PINPOINT
PRECISE TIMING OF DEEP CONVECTION...BUT HAVE STARTED TO TWEAK
DAYTIME POPS DOWN AND NOCTURNAL POPS UP TO HELP ACCOUNT FOR TYPICAL
DIURNAL PATTERN THIS TIME OF YEAR.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1048 PM CDT SUN JUN 9 2013
FOR THE 06Z TAFS...CONFIDENCE IS NOT REAL HIGH THROUGH SUNRISE
MONDAY. WITH DECREASING WINDS AND CLOUDS...AM STILL CONCERNED
ABOUT RADIATIONAL FOG DEVELOPING THROUGH THE AREA. RADIATIONAL FOG
IS DIFFICULT TO FORECAST FOR ANY PARTICULAR SPOT LOCATION. THAT
SAID...IT IS DISTURBING THAT SOME CEILINGS HAVE GONE UNDER 1000
FEET EAST OF I 29...AND IN SOUTHWEST MN...VISIBILITIES ARE ALREADY
RANGING ANYWHERE FROM A 1/2 MILE AT SLAYTON TO 10 MILES. THEREFORE
WITH THE MOIST GROUND AND VERY SMALL SURFACE DEW POINT DEPRESSIONS...
AREAS OF FOG IS A LIKELY SCENARIO LATE TONIGHT AND EARLY MONDAY.
FOR NOW...KEPT TEMPO IFR CONDITIONS FOR THE THREE TAF SITES AROUND
THE SUNRISE HOURS. BUT IT MUST BE NOTED THAT CONDITIONS COULD GET
WORSE THAN THIS AT LEAST FOR A BRIEF PERIOD OF TIME. UNFORTUNATELY
THAT BRIEF PERIOD OF TIME WOULD LIKELY COINCIDE WITH EARLY MORNING
FLIGHTS. SO THIS WILL NEED WATCHED VERY CLOSELY AND ALSO HEDGED
WITH A SCT003 DECK AT KFSD AND KSUX AS A HEADS UP. OTHERWISE
TOWARD MID MORNING...IT WILL BE VFR AS ANY FOG FORMATION SHOULD BE
FAIRLY SHALLOW IN DEPTH...AT LEAST ALONG AND WEST OF I 29.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...DENSE FOG ADVISORY UNTIL 9 AM CDT THIS MORNING FOR SDZ038>040-
053>056-059>062-065>071.
MN...DENSE FOG ADVISORY UNTIL 9 AM CDT THIS MORNING FOR MNZ071-072-
080-097-098.
IA...NONE.
NE...DENSE FOG ADVISORY UNTIL 9 AM CDT THIS MORNING FOR NEZ013-014.
&&
$$
SHORT TERM...JH
LONG TERM...
AVIATION...MJ
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
549 PM CDT MON JUN 10 2013
.AVIATION 00Z DISCUSSION...
FRONTAL BOUNDARY TO CROSS THE REMAINDER OF THE MID STATE BY MID TO
LATE EVENING. ISOLATED TO SCATTERED CONVECTION WILL BE POSSIBLE
ALONG AND JUST AHEAD OF THE BOUNDARY. CONVECTION TO TERMINATE AT
CSV BY 03Z. FOLLOWING THIS...SOME PATCHY FOG POSSIBLE CSV BY 12Z WITH
VSBYS AS LOW AS 1SM...1-3SM POSSIBLE FOR CKV AND BNA. PLENTIFUL
SUNSHINE FOR YOUR TUESDAY WITH JUST A FEW CLDS AT THE 4KFT LEVEL.
&&
.PREV DISCUSSION... /ISSUED 440 PM CDT MON JUN 10 2013/
MESOSCALE UPDATE...
RADAR INDICATING THAT THE FRONTAL BOUNDARY EXTENDS FROM
SPRINGFIELD TN SW THROUGH DICKSON COUNTY. LAPS DATA STILL SHOWING
ELEVATED HELICITY VALUES ALONG AND JUST AHEAD OF THE BOUNDARY.
THUS...WILL DELAY CANCELLING ADDITIONAL WATCH AREAS UNTIL FRONTAL
BOUNDARY MOVES EAST OF CURRENT WATCH COUNTIES. WITHIN THE PAST
HOUR...SOME MINOR ROTATION WAS STILL INDICATED OVER OUR WESTERN
COUNTIES. LATEST HRRR STILL REFRAINS FROM ADDITIONAL DEVELOPMENT
BUT WILL STILL WAIT FOR THE FROPA AND WILL THEN COMMENCE WITH
CANCELLATIONS.
OTHERWISE...INTENSE STORMS OVER THE NORTHERN AND CENTRAL PLATEAU
CONTINUES. THOUGH SLIGHTLY WEAKER...APPRECIABLE SHEAR STILL EXISTS
OVER THE CURRENT WATCH AREA.
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
21
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
440 PM CDT MON JUN 10 2013
.MESOSCALE UPDATE...
RADAR INDICATING THAT THE FRONTAL BOUNDARY EXTENDS FROM
SPRINGFIELD TN SW THROUGH DICKSON COUNTY. LAPS DATA STILL SHOWING
ELEVATED HELICITY VALUES ALONG AND JUST AHEAD OF THE BOUNDARY.
THUS...WILL DELAY CANCELLING ADDITIONAL WATCH AREAS UNTIL FRONTAL
BOUNDARY MOVES EAST OF CURRENT WATCH COUNTIES. WITHIN THE PAST
HOUR...SOME MINOR ROTATION WAS STILL INDICATED OVER OUR WESTERN
COUNTIES. LATEST HRRR STILL REFRAINS FROM ADDITIONAL DEVELOPMENT
BUT WILL STILL WAIT FOR THE FROPA AND WILL THEN COMMENCE WITH
CANCELLATIONS.
OTHERWISE...INTENSE STORMS OVER THE NORTHERN AND CENTRAL PLATEAU
CONTINUES. THOUGH SLIGHTLY WEAKER...APPRECIABLE SHEAR STILL EXISTS
OVER THE CURRENT WATCH AREA.
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
21
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
1123 PM CDT SUN JUN 9 2013
.UPDATE...FOR 06Z AVIATION FORECAST
&&
.AVIATION...
BAND OF CONVECTION HAS SLOWED TO A CRAWL FROM EARLIER PROJECTIONS
AND CONTINUES TO WEAKEN WHILE DIMINISHING IN COVERAGE. LOW CONFIDENCE
IN TERMINAL FORECASTS ESPECIALLY FIRST 12 HOURS. CLARKSVILLE STILL
IN THE RAIN AND WILL BE FOR A COUPLE MORE HOURS. NASHVILLE YET TO
GET RAIN BUT WILL SHORTLY. HAVE INCLUDED THUNDER FROM 06Z TO 08Z
THEN VICINITY SHOWER THROUGH THE OVERNIGHT. HAVE VICINITY SHOWERS
AT CROSSVILLE BECOMING PREDOMINATE AROUND 09Z AND CONTINUE THROUGH
14Z. COLD UPPER LOW WILL DROP DOWN INTO THE OHIO VALLEY ON MONDAY
WITH INCREASED INSTABILITY IN THE AFTERNOON ACROSS MY CWA SO HAVE
INCLUDED VICINITY THUNDERSTORMS AT ALL TERMINALS AFTER 18Z MONDAY.
BOYD
&&
.PREV DISCUSSION... /ISSUED 919 PM CDT SUN JUN 9 2013/
MESOSCALE UPDATE...
CONVECTIVE LINE CONTINUING TO HOLD TOGETHER BUT OVERALL WEAKENING
HAS OCCURRED DURING THE LAST HOUR. THE ESTIMATED TIME OF ARRIVAL
IN DOWNTOWN NASHVILLE IS 1020 PM CDT.
BOYD
PREV DISCUSSION... /ISSUED 857 PM CDT SUN JUN 9 2013/
MESOSCALE UPDATE...
LINE SEGMENT MOVING INTO MONTGOMERY COUNTY REMAINS STRONG OTHERWISE
LINE OF CONVECTION OVERALL HAS WEAKENED. EXPECT THIS TREND TO CONTINUE.
RAINFALL IN SOUTHWEST BENTON COUNTY TOTALED 1.75 INCHES. FLASH
FLOOD GUIDANCE IS JUST ABOVE 2 INCHES FOR THE AREA. THE HEAVIER
RAINS HAVE NOW PULLED EAST.
BOYD
PREV DISCUSSION... /ISSUED 814 PM CDT SUN JUN 9 2013/
UPDATE...
HAVE UPDATED GRIDS AND ZONES TO REFLECT BETTER THE APPROACHING
SHOWERS AND STORMS NOW CROSSING THE TENNESSEE RIVER. ALTHOUGH A
STORM OR TWO COULD BE STRONG TO SEVERE STILL THINK ACTIVITY WILL
GENERALLY WEAKEN AS IT MOVES FARTHER EAST INTO MIDDLE TENNESSEE
THIS EVENING...WITH LOSS OF HEATING AND UPPER SUPPORT.
STATIONARY FRONT FROM WESTERN TENNESSEE DOWN INTO LOUISIANA WITH
CONVECTION ALL ALONG THIS BOUNDARY. CLOUDS TOPS HAVE BECOME
COLDER LAST COUPLE OF HOURS ALONG THE BOUNDARY WITH SURFACE
DEWPOINTS AROUND 70 DEGREES. BOUNDARY MAY WORK INTO WESTERN
MIDDLE TENNESSEE OVERNIGHT AND WITH TRAINING OF ECHOES WE COULD BE
LOOKING AT LOCALLY HEAVY RAINFALL.
BOYD
PREV DISCUSSION... /ISSUED 752 PM CDT SUN JUN 9 2013/
MESOSCALE UPDATE...
LINE OF CONVECTION NEARING TENNESSEE RIVER AT 0030Z HAS PULLED
AHEAD OF COLDER AIR ALOFT AND ALONG WITH LOSS OF HEATING
EXPECT CONVECTION TO CONTINUE TO WEAKEN AS IT ADVANCES EASTWARD
INTO WESTERN MIDDLE TENNESSEE OVER THE NEXT 1 TO 2 HOURS BUT THERE
STILL COULD BE A STRONG STORM OR TWO.
HAVE SOME CONCERN FOR STATIONARY FRONT THAT EXTENDS FROM WEST
TENNESSEE DOWN INTO LOUISIANA AND A WAVE THAT HAS JUST DEVELOPED ON THE
FRONT IN LOUISIANA. SURFACE DEWPOINTS AROUND 70 EXTENDS ALL ALONG
THIS BOUNDARY. WILL HAVE TO WATCH FOR CONVECTION TRAINING
NORTHEAST OVERNIGHT.
BOYD
PREV DISCUSSION... /ISSUED 704 PM CDT SUN JUN 9 2013/
MESOSCALE UPDATE...
LINE OF STRONG CONVECTION CURRENTLY MOVING EASTWARD THROUGH WEST
TENNESSEE AND WAS 40 MILES WEST OF THE TENNESSEE RIVER AT 00Z. AM
EXPECTING THIS ACTIVITY TO WEAKEN AS IT CROSSES THE TENNESSEE
RIVER.
BOYD
PREV DISCUSSION... /ISSUED 641 PM CDT SUN JUN 9 2013/
UPDATE...FOR 00Z AVIATION FORECAST
AVIATION...EXPECT STORM STRENGTH TO DIMINISH AFTER SUNSET BUT
SCATTERED CONVECTION WILL LIKELY CONTINUE THROUGH THE OVERNIGHT
HOURS ACROSS MIDDLE TENNESSEE. SLUGGISH UPPER TROUGH CENTERED OVER
MIDDLE MISSISSIPPI VALLEY AT LATE AFTERNOON WILL MOVE DOWN INTO
EASTERN ILLINOIS BY 12Z MONDAY. EXPECT SOME SCATTERED CONVECTION
DURING THE DAY ON MONDAY AS UPPER TROUGH AXIS WITH COLDER TEMPS
SWINGS ACROSS THE TENNESSEE VALLEY.
MESOSCALE...STORM CELL MOVING INTO SOUTHWEST SUMNER MAY BE MORE
OF A RED HERRING BUT DOES HAVE A SUPERCELLULAR APPEARANCE (ITS GOT
THE LOOK). INBOUND WINDS WERE ON THE ORDER OF 35 KNOTS AT 2326Z.
STORM HAS TURNED RIGHT LAST 20 MINUTES TAPPING ENVIORNMENTAL WINDS
AND MORE HELICITY.
BOYD
PREV DISCUSSION... /ISSUED 446 PM CDT SUN JUN 9 2013/
MESOSCALE UPDATE...
500 MBAR COLD TEMP AXIS RUNNING DOWN THROUGH EASTERN MISSOURI AND
DOWN THROUGH EASTERN ARKANSAS JUST WEST OF MISSISSIPPI RIVER AT
21Z. THIS AXIS OF COLDER TEMPS WILL BEGIN SWEEPING INTO THE
WESTERN AREAS OF CURRENT WW SHORTLY WHICH WILL ENHANCE ACTIVITY
IN THOSE AREAS FOR NEXT FEW HOURS. LATEST SREF RUN WEAKENS INSTABILITY
IN MIDDLE TENNESSEE RATHER QUICKLY AFTER SUNDOWN. THIS ALSO BROUGHT
OUT BY H-TRIPLE-R HIGH RESOLUTION MODEL. THINK BEST SCENARIO AT
THIS TIME WOULD BE FOR LINE OF STRONG TO POSSIBLE SEVERE
CONVECTION TO DEVELOP ALONG MISSISSIPPI RIVER BY 00Z AND MOVE
EASTWARD INTO WESTERN TENNESSEE AND BEGIN WEAKENING BY 03Z AS IT
APPROACHES THE TENNESSEE RIVER AND CONTINUE WEAKENING AS IT MOVES
INTO MIDDLE TENNESSEE FROM 03Z AND 06Z.
BOYD
PREV DISCUSSION... /ISSUED 307 PM CDT SUN JUN 9 2013/
HE BULK OF THE CONVECTION THIS AFTERNOON HAS SHIFTED ACROSS EASTERN
MIDDLE TN AS THE UPPER DISTURBANCE CONTINUES TO PULL OFF TO THE EAST.
LATEST LAPS INSTABILITY PARAMETERS IS SHOWING AN INCREASE IN
INSTABILITY ACROSS WESTERN AREAS.
SFC AND UPPER LEVEL TROUGH AXIS IS STACKED NICELY AND EXTENDS
SOUTHWARD FROM IOWA. THESE 2 FEATURES WILL REMAIN IN PHASE AND WILL
TRACK EASTWARD ACROSS THE MID STATE OVERNIGHT. SHOULD SEE ISOL TO
SCATTERED CONVECTION REDEVELOP LATE THIS AFTERNOON AND EVENING
ACROSS WESTERN MIDDLE TN AND A FEW STORMS COULD REACH STRONG LEVELS.
THEN...LATER TONIGHT...A LINE OF THUNDERSTORMS WILL MOVE THROUGH
THE MID STATE...A FEW STORMS COULD AGAIN REACH STRONG LEVELS WITH
HIGH WINDS AND SOME SMALL HAIL. TIMING OF THE LINE APPEARS TO BE
AROUND 8PM TO 2AM ACROSS WESTERN MIDDLE TN AND 11PM TO 5AM ACROSS
EASTERN AREAS. LATEST HRRR DATA APPEARS TO WANT TO WEAKEN THE
SYSTEM BY THE TIME IT REACHES INTO EASTERN MIDDLE TN.
ON MONDAY...NAM MODEL WILL BE TOSSED AS GRAPHICS DEPICT NEAR 70 DEW
POINTS AT 18Z...AND THIS IN TURN HAS EVOKED OVERLY AGGRESSIVE
CONVECTIVE FEEDBACK. NUMERICAL MET DATA SHOWS DRIER AIR MIXING DOWN
TO THE SFC WITH DEWS IN THE LOWER 60S. GFS AND MAV DATA SHOWS EVEN
LOWER DEWPOINTS. NEVERTHELESS...WE WILL DESTABILIZE BY LATE
AFTERNOON WITH MID AND UPPER LEVEL CAPES REINFORCED WITH THE UPPER
TROUGHING PATTERN. COULD SEE ISOL TO SCT STRONG TO SVR
CONVECTION...WIND AND HAIL.
MONDAY NIGHT...DRIER AIR TO WORK IN AS THE UPPER TROUGH PULLS
EASTWARD. POPS WILL THEREFORE SHUTDOWN WITH DRY WEATHER THROUGH
WEDNESDAY. A DEFINITIVE WARMING TREND WILL BE AT HAND AS UPPER HIGH
STRENGTHENS OVER TX AND OUR HEIGHTS RISE.
IN THE EXT FCST...WEAK NORTHWEST FLOW WILL SET THE STAGE FOR
POTENTIAL MCS IMPACTS...THE FIRST OF WHICH WILL BE ON THURSDAY. THEN
ANOTHER POTENTIAL MCS FOR SAT OR SUN. OTHERWISE...WARM CONDITIONS
WITH HIGHS GENERALLY IN THE LOWER 90S WEST OF PLATEAU.
VERSUS THE MEX GUIDANCE...AGAIN...THE MEX APPEARS TO BE TOO
AGGRESSIVE WITH THAT 97 AT BNA FOR WED. WILL CONTINUE TO UNDERCUT
AND GO 94. A GENERAL UNDERCUT WILL BE UTILIZED THROUGHOUT THE
EXTENDED.
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
01
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
902 PM CDT TUE JUN 11 2013
.UPDATE...
SEE EVENING UPDATE.
&&
.DISCUSSION...
THE WEAK SHEAR AXIS THAT HAS BEEN OVER SE TX HAS SHIFTED WEST AND
NARROWED SIGNIFICANTLY. UPPER LEVEL RIDGING IS BUILDING INTO THE
REGION AND UPPER LEVEL WINDS ARE BECOMING INCREASINGLY CONVERGENT.
850 MB MOISTURE IS STILL PLENTIFUL OVER THE STATE BUT 850 MB DRYING
IS WORKING INTO THE AREA FROM THE EAST. 700 MB HEIGHTS AND TEMPS
ARE INCREASING AND FEEL THIS WILL INCREASE THE CAPPING OVER THE
REGION. NAM 12 SOUNDINGS STILL SHOW A BREAKABLE CAP FOR WEDNESDAY
BUT THERE WILL BE CONSIDERABLE SUBSIDENCE IMPARTED BY THE BUILDING
UPPER RIDGE TO OVERCOME. OVERALL...RAIN CHANCES WILL LIKELY BE
SHIFTING WEST AND SOUTH AND AWAY FROM SE TX.
AS FOR TONIGHT...TWEAKED SKY GRIDS AND RAISED MIN TEMPS ALONG THE
COAST TO MATCH LAST NIGHTS MIN VALUES IN THE LOWER 80S. OTHERWISE
THE PREVIOUS FCST LOOKS ON TARGET. 43
&&
.PREV DISCUSSION... /ISSUED 618 PM CDT TUE JUN 11 2013/
DISCUSSION...
SEE 00Z AVIATION DISCUSSION.
AVIATION...
GENERALLY VFR CONDS EXPECTED OVERNIGHT WITH ONLY SOME MVFR TYPE
FOG IN RURAL LOCATIONS. FCST SOUNDINGS ON WEDNESDAY STILL SHOW
PW VALUES AROUND 1.8 INCHES WITH NO CAPPING. ONE OF THESE DAYS...
SUBSIDENCE FROM THE UPPER RIDGE WILL KICK IN AND SQUASH RAIN
CHANCES. THE LATEST RAP CONTS TO SHOW PCPN ACROSS SE TX AND THIS
MODEL HAS BEEN PERFORMING RATHER WELL OF LATE. WILL START OUT WITH
VCSH IN SOUTHERN TAF SITES AND WAIT FOR 00Z DATA TO ARRIVE BEFORE
OR IF ADDING THUNDER. 43
PREV DISCUSSION... /ISSUED 339 PM CDT TUE JUN 11 2013/
DISCUSSION...
MAINLY WIDELY SCT SHOWERS AND THUNDERSTORMS HAVE DEVELOPED
THROUGH THIS AFTERNOON DUE TO HEATING AND MOIST ATMOSPHERE WITH PW
OF NEAR 2 INCHES. ACTIVITY SHOULD CONTINUE TO SPREAD INLAND AND
DECREASE THROUGH THE EVENING HOURS. THE MAIN CONCERN WITH THE
STORMS WILL BE BRIEF HEAVY RAINFALL WHERE MOST AREAS COULD PICK UP
A QUICK QUARTER TO A HALF INCH OF RAIN. THERE ARE A FEW ISOLATED
AREAS THAT HAVE PICKED UP BETWEEN 1 TO 2 INCHES OVER LAKE CONROE.
FREQUENT LIGHTNING WILL BE THE OTHER MAIN HAZARD.
CONVECTION TOMORROW IS A BIT MORE OF A QUESTION MARK. THINK THE
MAIN MOISTURE AXIS WILL BE THROUGH THE MIDDLE TX COAST INTO C TX
OR JUST OFF TO THE W AND SW. WATER VAPOR IMAGERY AND UPPER AIR
ANALYSIS HAVE UPPER LEVEL RIDGE OVER TX PANHANDLE INTO N TX. WEAK
SHEAR AXIS LOOKS LIKE IT HAS BEEN STRETCHED OUT WITH WEAK UPPER
LOW OVER MEXICO. THINK SUBSIDENCE MAY BE A BIT STRONGER TOMORROW
AS THE UPPER RIDGE BECOMES MORE DOMINANT. STILL MAY NEED TO HAVE
20 POPS IN THE FORECAST BUT HEDGING TOWARDS A MORE DRY FORECAST
WHICH MODELS HAVE. WOULD NOT BE SURPRISED IF A FEW ISO STORMS DO
DEVELOP BUT ACTIVITY WILL BE TO THE WEST.
UPPER LEVEL RIDGE WILL BE THE MAIN WEATHER FEATURE FOR THE END OF
THE WEEK SO DO EXPECT TEMPS TO WARM INTO THE MID 90S. UPPER 90S
MAY BE IN REACH THUR/FRI INTO SAT. GFS/ECMWF DO HOLD ONTO THE
UPPER LOW OVER MEXICO A BIT LONGER NOW AND THEN BRING THIS FEATURE
AROUND THE EDGE OF THE RIDGE INTO W TX AND N TX FOR THE WEEKEND.
THIS MAY WEAKEN THE RIDGE SOME SO MODELS HAVE TRENDED A COUPLE OF
DEGREES COOLER ON MAX TEMPS. DECIDED TO STILL STICK WITH MID/UPPER
90S WHICH WILL BE A GOOD 3-4 DEGREES WARMER THAN 12Z GUIDANCE.
RIDGE DOES BUILD BACK OVER S PLAINS EARLY NEXT WEEK SO EXPECT MORE
OF THE TYPICAL SUMMER TIME WEATHER WITH MIN TEMPS IN THE MID/UPPER
70S...MAX TEMPS IN MID 90S AND NO RAIN CHANCES.
39
MARINE...
LIGHT/MODERATE ONSHORE WINDS WILL CONTINUE ACROSS THE AREA THE NEXT
SEVERAL DAYS AS HIGH PRESSURE LINGERS OVER THE NRN GULF COAST. LONG
RANGE GUIDANCE (THESE RUNS AT LEAST) INDICATING THAT THE RIDGE OVER
THE SOUTHERN HALF OF THE U.S. WILL BE HOLDING...THEREBY PUSHING THE
POSSIBLE DEVELOPMENT IN THE BAY OF CAMPECHE INTO EASTERN MEXICO. NO
REAL ARGUMENTS WITH THAT SOLUTION GIVEN THE TIME SCALE/TIME OF YEAR.
OTHERWISE ADVISORIES/FLAGS REMAIN UNLIKELY THROUGH THIS FCST PERIOD.
41
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 74 94 74 96 75 / 10 10 10 10 10
HOUSTON (IAH) 75 94 75 95 75 / 10 10 10 10 10
GALVESTON (GLS) 79 88 80 89 80 / 10 10 10 10 10
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
DISCUSSION...43
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
618 PM CDT TUE JUN 11 2013
.DISCUSSION...
SEE 00Z AVIATION DISCUSSION.
&&
.AVIATION...
GENERALLY VFR CONDS EXPECTED OVERNIGHT WITH ONLY SOME MVFR TYPE
FOG IN RURAL LOCATIONS. FCST SOUNDINGS ON WEDNESDAY STILL SHOW
PW VALUES AROUND 1.8 INCHES WITH NO CAPPING. ONE OF THESE DAYS...
SUBSIDENCE FROM THE UPPER RIDGE WILL KICK IN AND SQUASH RAIN
CHANCES. THE LATEST RAP CONTS TO SHOW PCPN ACROSS SE TX AND THIS
MODEL HAS BEEN PERFORMING RATHER WELL OF LATE. WILL START OUT WITH
VCSH IN SOUTHERN TAF SITES AND WAIT FOR 00Z DATA TO ARRIVE BEFORE
ADDING THUNDER. 43
&&
.PREV DISCUSSION... /ISSUED 339 PM CDT TUE JUN 11 2013/
DISCUSSION...
MAINLY WIDELY SCT SHOWERS AND THUNDERSTORMS HAVE DEVELOPED
THROUGH THIS AFTERNOON DUE TO HEATING AND MOIST ATMOSPHERE WITH PW
OF NEAR 2 INCHES. ACTIVITY SHOULD CONTINUE TO SPREAD INLAND AND
DECREASE THROUGH THE EVENING HOURS. THE MAIN CONCERN WITH THE
STORMS WILL BE BRIEF HEAVY RAINFALL WHERE MOST AREAS COULD PICK UP
A QUICK QUARTER TO A HALF INCH OF RAIN. THERE ARE A FEW ISOLATED
AREAS THAT HAVE PICKED UP BETWEEN 1 TO 2 INCHES OVER LAKE CONROE.
FREQUENT LIGHTNING WILL BE THE OTHER MAIN HAZARD.
CONVECTION TOMORROW IS A BIT MORE OF A QUESTION MARK. THINK THE
MAIN MOISTURE AXIS WILL BE THROUGH THE MIDDLE TX COAST INTO C TX
OR JUST OFF TO THE W AND SW. WATER VAPOR IMAGERY AND UPPER AIR
ANALYSIS HAVE UPPER LEVEL RIDGE OVER TX PANHANDLE INTO N TX. WEAK
SHEAR AXIS LOOKS LIKE IT HAS BEEN STRETCHED OUT WITH WEAK UPPER
LOW OVER MEXICO. THINK SUBSIDENCE MAY BE A BIT STRONGER TOMORROW
AS THE UPPER RIDGE BECOMES MORE DOMINANT. STILL MAY NEED TO HAVE
20 POPS IN THE FORECAST BUT HEDGING TOWARDS A MORE DRY FORECAST
WHICH MODELS HAVE. WOULD NOT BE SURPRISED IF A FEW ISO STORMS DO
DEVELOP BUT ACTIVITY WILL BE TO THE WEST.
UPPER LEVEL RIDGE WILL BE THE MAIN WEATHER FEATURE FOR THE END OF
THE WEEK SO DO EXPECT TEMPS TO WARM INTO THE MID 90S. UPPER 90S
MAY BE IN REACH THUR/FRI INTO SAT. GFS/ECMWF DO HOLD ONTO THE
UPPER LOW OVER MEXICO A BIT LONGER NOW AND THEN BRING THIS FEATURE
AROUND THE EDGE OF THE RIDGE INTO W TX AND N TX FOR THE WEEKEND.
THIS MAY WEAKEN THE RIDGE SOME SO MODELS HAVE TRENDED A COUPLE OF
DEGREES COOLER ON MAX TEMPS. DECIDED TO STILL STICK WITH MID/UPPER
90S WHICH WILL BE A GOOD 3-4 DEGREES WARMER THAN 12Z GUIDANCE.
RIDGE DOES BUILD BACK OVER S PLAINS EARLY NEXT WEEK SO EXPECT MORE
OF THE TYPICAL SUMMER TIME WEATHER WITH MIN TEMPS IN THE MID/UPPER
70S...MAX TEMPS IN MID 90S AND NO RAIN CHANCES.
39
MARINE...
LIGHT/MODERATE ONSHORE WINDS WILL CONTINUE ACROSS THE AREA THE NEXT
SEVERAL DAYS AS HIGH PRESSURE LINGERS OVER THE NRN GULF COAST. LONG
RANGE GUIDANCE (THESE RUNS AT LEAST) INDICATING THAT THE RIDGE OVER
THE SOUTHERN HALF OF THE U.S. WILL BE HOLDING...THEREBY PUSHING THE
POSSIBLE DEVELOPMENT IN THE BAY OF CAMPECHE INTO EASTERN MEXICO. NO
REAL ARGUMENTS WITH THAT SOLUTION GIVEN THE TIME SCALE/TIME OF YEAR.
OTHERWISE ADVISORIES/FLAGS REMAIN UNLIKELY THROUGH THIS FCST PERIOD.
41
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 74 94 74 96 75 / 10 10 10 10 10
HOUSTON (IAH) 75 94 75 95 75 / 10 10 10 10 10
GALVESTON (GLS) 79 88 80 89 80 / 10 10 10 10 10
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
DISCUSSION...43
AVIATION/MARINE...43
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
1058 AM CDT MON JUN 10 2013
.UPDATE...
MORNING FORECAST UPDATE.
&&
.DISCUSSION...
MAIN ISSUE TODAY MAY BE CONVECTION AGAIN BUT A LOT MORE ISOLATED
COMPARED TO YESTERDAY. WATER VAPOR IMAGERY SHOWS THAT YESTERDAY`S
TROUGH AXIS HAS LEFT BEHIND A WEAK CLOSED LOW OVER S TX/LOWER TX
COAST. MAY JUST KEEP ENVIRONMENT FAVORABLE FOR CONVECTION WITH
MORE DAYTIME HEATING AND SEA BREEZE BOUNDARY DEVELOPING. THE
12/13Z HRRR RUNS HAVE CONVECTION DEVELOPING 17-18Z AND ENDING BY
22Z. FORECAST HAS 20/30 POPS AND THINK THIS MAY BE ON TRACK.
COVERAGE MAY NOT BE AS MUCH TO NEED 30 POPS BUT LOOKS REASONABLE.
OVERALL FORECAST LOOKS ON TRACK AND WILL NOT ISSUE AN UPDATE.
39
&&
.PREV DISCUSSION... /ISSUED 635 AM CDT MON JUN 10 2013/
DISCUSSION...
SEE AVIATION FOR 12Z TAF ISSUANCE.
AVIATION...
CURRENTLY HAVE LIFR AND IFR CONDITIONS AT RURAL SITES DUE TO
MORNING FOG. URBAN SITES HAVE BEEN SPARED MOST OF THE FOGGY
CONDITIONS. FOG SHOULD QUICKLY BURN OFF THIS MORNING PRODUCING VFR
CONDITIONS ACROSS THE AREA. THERE WILL BE ANOTHER CHANCE OF
SHOWERS AND THUNDERSTORMS THIS AFTERNOON AS THE UPPER LEVEL
WEAKNESS REMAINS IN CLOSE PROXIMITY TO THE AREA. COVERAGE SHOULD
BE MORE LIMITED TODAY AS PRECIPITABLE WATER VALUES HAVE ALREADY
COME DOWN SINCE YESTERDAY. VALUES OF AROUND 1.50" THOUGH STILL
SHOULD SUPPORT RAIN. SOUNDINGS REVEAL MODEST MOISTURE AND
INSTABILITY VALUES WITH CONVECTIVE TEMPERATURES AROUND 90 DEGREES
WHICH APPEAR TO BE VERY ACHIEVABLE THIS AFTERNOON. WHERE MOISTURE
IS MORE LIMITED TOWARDS THE NORTH MIGHT HAVE A HARD TIME GETTING
RAIN BUT AT KIAH AND SOUTHWARDS STILL SHOULD HAVE ENOUGH MOISTURE
TO WORK WITH. 23
PREV DISCUSSION... /ISSUED 341 AM CDT MON JUN 10 2013/
DISCUSSION...
AN ELONGATED MID/UPPER LEVEL SHEAR AXIS IS ALONG THE UPPER TEXAS COAST
EARLY THIS MORNING. PER HIGH RESOLUTION MODELS...EXPECT TO SEE INCREASING
SHOWER/THUNDERSTORM DEVELOPMENT ACROSS THE GULF WATERS BEFORE SUNRISE...
DEVELOPMENT IN/NEAR THE COASTAL COUNTIES THIS MORNING...AND FURTHER
INLAND THIS AFTERNOON. EXPECT A LOT LESS INLAND COVERAGE THAN THE AREA
SAW YESTERDAY. AS THIS WEEK PROGRESSES...STILL EXPECT TO SEE A DRYING
AND WARMING TREND FOR A MAJORITY OF THE AREA AS UPPER LEVEL RIDGING
BUILDS ACROSS THE AREA (SPOTS AROUND THE MATAGORDA BAY AREA MIGHT END
UP BEING THE BEING THE LAST TO DRY OUT). STILL CARRYING MID TO UPPER
90S FOR HIGHS FOR MUCH OF INLAND SOUTHEAST TEXAS BEGINNING ON WEDNESDAY
AND CONTINUE THROUGH THE END OF THE WEEK AND ON INTO THE WEEKEND. 42
MARINE...
THE UPPER LEVEL DISTURBANCE THAT GAVE US RAINFALL YESTERDAY WILL
CONTINUE TO RETROGRADE TO THE WEST TODAY WHILE THE MAIN TROUGH AXIS
MOVES OFF TOWARDS THE EAST. WATERS COULD SEE SOME MORE SHOWERS AND
THUNDERSTORMS TODAY AS POCKETS OF VORTICITY MOVE AROUND THE
DISTURBANCE. LIGHT TO MODERATE ONSHORE WINDS WITH MOSTLY LOW SEAS
CAN BE EXPECTED THROUGH THE WEEK.
23
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 94 74 95 74 95 / 10 10 10 10 10
HOUSTON (IAH) 93 74 94 75 94 / 30 10 20 10 10
GALVESTON (GLS) 87 79 88 80 88 / 30 10 20 10 10
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
DISCUSSION...39
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
1141 PM CDT SUN JUN 9 2013
.DISCUSSION...
SEE 06Z AVIATION DISCUSSION.
&&
.AVIATION...
WET GROUND AND CLEARING SKIES SHOULD ALLOW SOME PATCHY FOG TO
DEVELOP OVER RURAL TAF SITES TONIGHT. ANY MVFR VSBY/CIGS WILL MIX
OUT EARLY MONDAY MORNING. GFS CONTS TO BE MORE AGGRESSIVE WITH
RAIN CHANCES ON MONDAY DUE TO AN INVERTED UPPER LEVEL TROUGH OVER
DEEP SOUTH TEXAS. FCST SOUNDINGS DON`T SHOW MUCH IN THE WAY OF A
CAP AND WITH PW VALUES NEAR 1.70 INCHES AND CONVECTIVE TEMPS IN
THE UPPER 80S...FEEL SHRA/TSRA WILL BE POSSIBLE OVER MAINLY THE
SOUTHERN TAF SITES...OR KIAH SOUTHWARD. CONDS IMPROVE RAPIDLY BY
11/00Z WITH VFR CONDS EXPECTED MONDAY NIGHT. 43
&&
.PREV DISCUSSION... /ISSUED 849 PM CDT SUN JUN 9 2013/
DISCUSSION...
THIS EVENINGS SOUNDINGS HAVE PRECIPITABLE WATER VALUES OF 1.87
AND 1.56 INCHES. THE ATMOSPHERE IS MORE STABLE THAN IT WAS 24
HOURS AGO...BUT ISOLATED TO WIDELY SCATTERED SHOWERS AND
THUNDERSTORMS ARE STILL POSSIBLE OVER THE EASTERN PORTIONS OF
SOUTHEAST TEXAS TOMORROW AFTERNOON. THE AXIS OF THE UPPER LEVEL
TROUGH SHOULD BE JUST OFF THE COAST. WITH SUBSIDENCE OVER THE
AREA AND CONVERGENCE AT 200-300 MB. THE COVERAGE SHOULD BE
SPOTTIER THAN IT WAS TODAY.
OVERALL...THE PREVIOUS FORECAST LOOKS TO BE ON TRACK. NO CHANGES
ARE NECESSARY AT THIS TIME. 44
PREV DISCUSSION... /ISSUED 622 PM CDT SUN JUN 9 2013/
DISCUSSION...
SEE 00Z AVIATION DISCUSSION.
AVIATION...
CONDITIONS HAVE STABILIZED ACROSS SE TX AND AM EXPECTING THE
CIRRUS SHIELD TO DISSIPATE IN THE NEXT HOUR OR SO. CONVECTION
SHOULD REMAIN TO THE EAST AND TO THE WEST OF SE TX. AM A LITTLE
CONCERNED ABOUT PATCHY FOG IN RURAL AREAS OVERNIGHT WITH GROUNDS
REMAINING WET AND LIGHT WINDS. FCST SOUNDINGS ON MONDAY KINDA
CAUGHT ME BY SURPRISE. 18Z SOUNDINGS SHOW A BREAKABLE CAP AND
CONVECTIVE TEMPS IN THE UPPER 80S. THE GFS IN PARTICULAR IS
AGGRESSIVE WITH RAIN CHANCES AND GETS SOME SUPPORT FROM THE HI-RES
ARW. THE LATEST RAP SHOWS A WEAK TROUGH AXIS ACROSS SE TX AT 16Z
SO FEEL SOME PCPN SHOULD DEVELOP WITH FURTHER HEATING. ADDED VCSH
FOR MON AFTN AND WILL WAIT FOR 00Z RUNS BEFORE EITHER ADDING
THUNDER OR REMOVING PCPN ALL TOGETHER. 43
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 72 94 74 95 74 / 20 10 10 10 10
HOUSTON (IAH) 73 93 75 94 75 / 20 20 10 10 10
GALVESTON (GLS) 81 87 80 88 80 / 30 20 10 20 10
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
DISCUSSION...44
AVIATION/MARINE...43
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
645 PM CDT TUE JUN 11 2013
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 345 PM CDT TUE JUN 11 2013
AT 3 PM...SCATTERED SHOWERS CONTINUED TO BE FOUND FROM THE
EASTERN DAKOTAS SOUTHEAST INTO NORTHEAST ILLINOIS AND SOUTHEAST
WISCONSIN. THESE SHOWERS ARE DEVELOPING ABOVE THE CAP DUE TO WEAK
TO MODERATE 700 TO 300 MB MOISTURE TRANSPORT...WEAK TO MODERATE
310 TO 320K ISENTROPIC UPGLIDE...WEAK TO MODERATE 700 TO 500 MB
FRONTOGENESIS...AND THE RIGHT ENTRANCE REGION OF A 100 KNOT
250 MB JET.
THE 11.12Z MODELS THAT THE 700 MB SHORT WAVE TROUGH OVER THE
CENTRAL DAKOTAS WILL MOVE ACROSS WEST-CENTRAL AND SOUTHWEST `
MINNESOTA LATE THIS AFTERNOON...AND THROUGH OUR AREA FROM LATE
EVENING INTO THE EARLY OVERNIGHT. THE 700 MB VAD WIND AT KABR JUST
RECENTLY WENT FROM WEST TO SOUTHWEST. AHEAD OF THIS WAVE...THE
MODELS CONTINUE TO SHOW THAT THE 700 TO 500 MB FRONTOGENESIS...
700 TO 300 MB MOISTURE TRANSPORT...AND 310 TO 320K ISENTROPIC LIFT
WILL INCREASES ACROSS THE FORECAST AREA. THE HRRR SUGGESTS THAT
SHOWERS AND THUNDERSTORMS WILL BECOME MORE WIDESPREAD ALONG THE
FRONTOGENETIC WING AHEAD OF THIS WAVE BETWEEN 7 PM AND 10 PM IN
SOUTHEAST MINNESOTA...AND THEN SPREADS EAST INTO WESTERN
WISCONSIN MAINLY ALONG THE INTERSTATES OF 90 AND 94 BETWEEN 10 PM
AND 1 AM. AS THE SHORT WAVE MOVES INTO THE AREA EXPECT THE SHOWERS
AND THUNDERSTORMS TO SPREAD INTO NORTHEAST IOWA AND SOUTHWEST
WISCONSIN BETWEEN 11 PM AND 3 AM.
AFTER THIS SYSTEM MOVES THROUGH THE AREA...EXPECT A BREAK AND THEN
LOOKING FOR A MESOSCALE CONVECTIVE COMPLEX /LIKELY TO DEVELOP NEAR
RAPID CITY/ TO MOVE THROUGH THE AREA ON TUESDAY MORNING. THE
MODELS HAVE BEEN REALLY STRUGGLING WITH THE TIMING AND EVOLUTION OF
THIS SYSTEM. A FEW OF THE MESO MODELS HAVE SHOWED THAT A LINE OF
STORMS WOULD MOVE THROUGH THE AREA BETWEEN 5 AM AND 10 AM. 0-3 KM
SHEAR AND THE 700 TO 500 MB LAPSE RATES SUGGEST THAT THERE MAY BE
SOME DAMAGING WINDS ASSOCIATED WITH THIS LINE. MEANWHILE THE
ECMWF AND LATEST HRRR SUGGEST THAT THIS LINE MAY ARRIVE A BIT
LATER AND THAT THE LINE WILL NOT BE THAT STRONG WHEN IT MOVES
THROUGH THE AREA. BY FAR...THE ECMWF IS SLOWEST WITH THIS
SYSTEM...AND BY THE TIME THAT IT ARRIVES THERE IS NOT MUCH
INSTABILITY LEFT. AS A RESULT...THE SEVERE WEATHER THREAT IS STILL
UNCLEAR WITH THIS SYSTEM.
ANOTHER THING THAT WILL HAVE TO BE WATCHED TONIGHT IS THE THREAT
FOR HEAVY RAIN. BOTH THE GFS AND NAM/WRF SHOW THAT THE
PRECIPITABLE WATER VALUES WILL BE INCREASING UP TO 1.8 INCHES AND
THAT THE WARM CLOUD LAYER DEPTHS WILL BE INCREASING INTO THE 4 TO
4.5 KM RANGE. AS A RESULT...EXPECT THE SHOWERS AND THUNDERSTORMS
TO BECOME EFFICIENT RAIN PRODUCERS. WILL ESPECIALLY HAVE TO WATCH
FOR THE POTENTIAL OF TRAINING ALONG THE FRONTOGENETIC BAND.
RAINFALL AMOUNTS FROM 0.75 TO 1.50 INCHES LOOK POSSIBLE FROM
TONIGHT INTO WEDNESDAY MORNING. THERE MAY BE EVEN A FEW SPOTS THAT
COULD SEE UP TO 2 INCHES.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 345 PM CDT TUE JUN 11 2013
ON WEDNESDAY EVENING...THE MOISTURE TRANSPORT QUICKLY MOVES WELL
EAST OF THE AREA AS THE UPPER LEVEL LOW MOVES AWAY FROM THE
REGION. THIS IS BIT FASTER THAN ORIGINALLY EXPECTED...SO LOWERED
THE PRECIPITATION CHANCES DURING THE EVENING AND TOOK THEM OUT FOR
THE OVERNIGHT.
FROM FRIDAY NIGHT INTO THE WEEKEND...THE MODELS CONTINUE TO SHOW
THAT SEVERAL MESOSCALE CONVECTIVE COMPLEXES WILL DEVELOP OVER THE
NORTHERN PLAINS AND THEN MOVE THROUGH THE FORECAST AREA. WHILE
THIS HAS BEEN A CONSISTENT SIGNAL...THE MODELS HAVE BEEN REALLY
STRUGGLE WITH BOTH THEIR LOCATION AND TIMING. AT THIS TIME...THE
MOST CONSISTENT SIGNAL IS FOR FRIDAY NIGHT INTO SATURDAY
MORNING...SO WENT THE HIGHEST PRECIPITATION DURING THIS TIME FRAME.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING)
ISSUED AT 645 PM CDT TUE JUN 11 2013
WHEN AND WHERE A THUNDERSTORM COMPLEX ROLLS ACROSS THE REGION IS THE
MAIN FORECAST CONCERN. THERE STILL REMAINS SOME UNCERTAINTY ON THE
WHEN...AND POTENTIALLY THE IF TOO. MOST MESO MODELS SUPPORT
DEVELOPING A THUNDERSTORM CLUSTER OVER NEB/NORTHERN PLAINS AND
TAKING IT EAST OVERNIGHT...FAVORING A 09-12Z TIME FRAME FOR BRINGING
IT ACROSS THE AREA. WILL STICK WITH THIS. ENOUGH INSTABILTY AND
FAVORABLE WIND FIELDS THAT STRONG/DAMAGING WIND GUSTS WOULD BE
POSSIBLE ON THE LEADING EDGE OF THIS THUNDERSTORM COMPLEX...WITH
SOME ENHANCEMENT IN GUSTINESS FROM A RELATIVELY DRY SUB CLOUD LAYER.
WILL CONTINUE THE MENTION FOR STRONGER STORM INDUCED GUSTS FOR A
FEW HOURS IN THE MORNING AT BOTH KRST AND KLSE. CIGS SHOULD FALL
INTO THE MVFR RANGE AS THE STORMS MOVE IN...WITH RAIN ASSOCIATED
VSBY REDUCTIONS. THREAT FOR TS SHOULD BE LIMITED AFTER THE MAIN
COMPLEX MOVES THROUGH...DUE TO LIMITED INSTABILITY INTO THE
AFTERNOON. SHRA WILL LIKELY LINGER ACROSS THE AREA FOR THE BETTER
PART OF THE DAY...DRIER BY THE EVENING AS THE STORM COMPLEX EXITS
SOUTHEAST.
&&
.HYDROLOGY...TONIGHT INTO WEDNESDAY
ISSUED AT 345 PM CDT TUE JUN 11 2013
FOR AREAS MAINLY ALONG AND SOUTH OF INTERSTATE 94 CORRIDOR...PLAN
ON RAINFALL AMOUNTS FROM TONIGHT THROUGH WEDNESDAY TO RANGE FROM
0.75 TO 1.50 INCHES WITH LOCALLY HIGHER AMOUNTS POSSIBLE. WITH WET
SOILS IN PLACE...EXPECT SOME RUNOFF ISSUES AND SOME SIGNIFICANT
WITHIN BANK RIVER RISES TO OCCUR. WILL HAVE TO KEEP A CLOSE EYE
ON ANY AREAS THAT MAY SEE LONGER DURATION/HIGHER RAINFALL RATES
FOR FLOODING POTENTIAL. STAY TUNED.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...BOYNE
LONG TERM....BOYNE
AVIATION.....RIECK
HYDROLOGY....BOYNE
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
309 PM CDT MON JUN 10 2013
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 309 PM CDT MON JUN 10 2013
CURRENTLY AS OF 20Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS
SHOWED AN UPPER LOW OVER SOUTHERN CALIFORNIA...SUBTROPICAL RIDGING
OVER NEW MEXICO AND COLORADO AND WEAK RIDGING EXTENDING FROM THE
SUBTROPICAL RIDGE INTO THE FORECAST AREA. ALSO OF NOTE IS A
SHORTWAVE IN EASTERN NORTH DAKOTA RIDING THROUGH NEARLY ZONAL FLOW
THERE. SUBSIDENCE UNDER THE WEAK RIDGING TRAPPED LOW LEVEL MOISTURE
AS SEEN ON THE 12Z MPX/DVN SOUNDINGS...WITH SATURATION NEARLY UP TO
800MB BUT PLENTY OF DRYING ABOVE THAT. THE RESULT WAS EXPANSIVE
STRATUS AND SOME FOG THIS MORNING. DAYTIME MIXING OVER THE PAST FEW
HOURS HAS REALLY HELPED DISSIPATE THE STRATUS...THOUGH. AIRMASS OVER
THE AREA WITH RESPECT TO WARMTH EXHIBITS 850MB TEMPS OF 10-13C PER
12Z RAOBS...WHICH ARE NEAR NORMAL. HOWEVER...UNDER THE SUBTROPICAL
RIDGE...850MB TEMPS ARE 22-26C OR 1.5-2 STANDARD DEVIATIONS ABOVE
NORMAL. 700MB TEMPS ARE ALSO QUITE WARM...RANGING FROM 14-17C FROM
RAPID CITY AND AMARILLO WEST TO SALT LAKE CITY. TO OUR
NORTHWEST...SCATTERED SHOWERS AND STORMS HAVE BEEN GOING ALL DAY
OVER NORTHEAST NORTH DAKOTA...AHEAD OF THE SHORTWAVE THERE.
THE SUBTROPICAL RIDGING IN NEW MEXICO AND COLORADO IS PROGGED TO
SHIFT EAST INTO THE CENTRAL PLAINS ON TUESDAY...PUSHED EAST BY THE
UPPER LOW IN SOUTHERN CALIFORNIA LIFTING AND SHEARING OUT INTO
WYOMING BY 00Z WEDNESDAY. THIS MEANS ALL THE WARM AIR OVER THE
ROCKIES WILL SPILL EAST AND TRY TO HEAD TOWARDS THE FORECAST AREA.
MEANWHILE...UPPER TROUGHING OVER SOUTH CENTRAL CANADA IS FORECAST
TO DROP INTO THE EASTERN GREAT LAKES ON TUESDAY...PROVIDING SOME
BLOCKING TO THE WARM AIR. AS A RESULT...WHILE 850MB TEMPS CLIMB BY
00Z WEDNESDAY TO 14C NORTH TO 18C SOUTH ACROSS THE FORECAST
AREA...READINGS OF 24-36C LOOK COMMON ACROSS MUCH OF NEBRASKA AND
KANSAS. NEVERTHELESS...A MUCH WARMER DAY LOOKS ON TAP FOR TUESDAY.
IF WE CAN MIX UP TO THE AFOREMENTIONED 850MB TEMPS...READINGS WOULD
TOP OUT IN THE UPPER 70S TO MID 80S...TEMPERATURES SOME LOCATIONS
HAVE NOT SEEN SINCE MID MAY.
WITH THE WARMER AIR COMING AT US...THERE IS ALWAYS A CONCERN FOR
ELEVATED CONVECTION. TONIGHT APPEARS DRY WITH THE BULK OF MOISTURE
TRANSPORT FROM 925MB TO 700MB ALL FOCUSED WEST OF THE AREA. IN
FACT...MUCH OF THE NIGHT SHOULD BE CLEAR WITH THE CURRENT CLOUDS
DISSIPATING WITH DIURNAL COOLING GIVEN THEIR NOW CELLULAR NATURE.
ON TUESDAY...THAT SHORTWAVE CURRENTLY IN EASTERN NORTH DAKOTA IS
PROGGED TO BYPASS US TO THE NORTH...ALONG WITH ITS RELATED
SHOWER/THUNDERSTORM ACTIVITY. HOWEVER...THERE ARE INDICATIONS OF
SOME VERY HIGH BASED SHOWERS AND POSSIBLY EVEN THUNDERSTORMS FROM
THE 10.06Z/12Z NAM...10.06Z HIRES ARW AND 10.12Z REGIONAL CANADIAN
ALL CROSSING THE FORECAST AREA DURING THE AFTERNOON HOURS. THESE
APPEAR TO COME OUT OF THE DAKOTAS TONIGHT ON THE LEADING EDGE OF
SOME 700MB MOISTURE TRANSPORT. GIVEN THE GOOD MODEL
AGREEMENT...HAVE INCREASED CLOUD COVER AND ADDED 20 PERCENT
CHANCES FOR SHOWERS AND THUNDERSTORMS. DID NOT GO ANY HIGHER WITH
THE CHANCES BECAUSE OF DRY AIR BELOW 700MB LIKELY ABSORBING SOME
OF THE RAIN. THE CLOUDS WILL HAMPER TEMPERATURES FROM CLIMBING TO
THEIR FULL MIXING VALUES MENTIONED EARLIER.
LASTLY...FOG POTENTIAL TONIGHT. SKIES CLEARING LATE IN THE DAY...
LIGHT WINDS FOR MUCH OF THE NIGHT AND MOIST SOILS ARE ALL VERY
FAVORABLE FOR FOG. THIS LOOKS ESPECIALLY TRUE IN VALLEYS WHERE
EVAPOTRANSPORATION OF MOISTURE CAN POOL.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 309 PM CDT MON JUN 10 2013
MAIN FOCUS CONTINUES TO BE ON THE POTENTIAL FOR SEVERE WEATHER...AND
IN GENERAL PRECIPITATION CHANCES...FROM TUESDAY NIGHT INTO WEDNESDAY
EVENING.
THE FORECAST IS PROBLEMATIC DURING THE TUESDAY NIGHT INTO WEDNESDAY
PERIOD...PRIMARILY RELATED TO ALL THE WARM AIR COMING OUT INTO THE
PLAINS THE NEXT 24 HOURS. SYNOPTICALLY...THE MAIN FEATURE TO LOCK
ONTO IS THE SHEARING OUT UPPER LOW OVER WYOMING AT 00Z WEDNESDAY...
WHICH MODELS ARE IN REALLY GOOD AGREEMENT TRACKING INTO CENTRAL
SOUTH DAKOTA BY 12Z WEDNESDAY AND THEN INTO CENTRAL IOWA BY 00Z
THURSDAY. MODELS ARE ALSO IN VERY GOOD AGREEMENT OF THUNDERSTORMS
DEVELOPING IN WESTERN SOUTH DAKOTA TUESDAY EVENING AS THE POTENT
SHORTWAVE MOVES IN THERE. USING THE 10.12Z MODEL RUNS AS WELL AS
PAST MODELS...A COUPLE OF SCENARIOS CAN PLAY OUT:
1. THERE ARE SOME INDICATIONS OF A WEAK SHORTWAVE COMING OUT OF
EASTERN COLORADO AND LIFTING TO THE SIOUX FALLS AREA BY 06Z
WEDNESDAY. THERE HAVE BEEN VARIOUS MODEL RUNS SUGGESTING THIS WILL
HELP BREAK THE CAPPING PRESENT BETWEEN 650-700MB...RESULTING IN AN
MCS WHICH THEN CORFIDI VECTORS WOULD BRING INTO SOUTHERN PORTIONS OF
THE FORECAST AREA BETWEEN 06-15Z WEDNESDAY. THE MCS COULD BE A BOW
ECHO. THE 10.06Z/12Z HI RES ARW MODELS...WHICH ARE TYPICALLY GOOD
STORM SCALE MODEL FORECASTS...HINT AT THIS SCENARIO.
2. SOME SCATTERED SHOWERS/STORMS FIRE THROUGH TUESDAY NIGHT...
ESPECIALLY AFTER MIDNIGHT ON THE LEADING EDGE OF THE CAPPING.
HOWEVER...NONE OF THESE ORGANIZE INTO AN MCS AS IN SCENARIO 1 WHICH
WOULD LIMIT SEVERE POTENTIAL. THE 10.12Z REGIONAL CANADIAN SUGGESTS
THIS SCENARIO.
3. NOTHING HAPPENS OR MAYBE ISOLATED STORMS AT BEST TUESDAY NIGHT
LIKE THE 10.12Z ECMWF...AND WE HAVE 1 OR 2 ROUNDS OF SHOWERS AND
THUNDERSTORMS AS THE POTENT SHORTWAVE HEADING INTO IOWA LATE IN THE
DAY MOVES IN.
SO FOR THE TUESDAY NIGHT/WEDNESDAY FORECAST...HAVE LOWERED
PRECIPITATION CHANCES FURTHER TUESDAY EVENING WHICH COULD EVEN END
UP DRY. AFTER MIDNIGHT...KEPT THE HIGHER CHANCES OF 60-70 GOING PER
SCENARIOS 1 AND 2...AND DID SHIFT THEM NORTH TO COME INTO BETTER
CONSENSUS. ALL 3 ABOVE SCENARIOS SUGGEST THE SECOND PART OF SCENARIO
3 IS TRUE...WHERE POTENTIAL FOR 1 OR 2 ROUNDS OF SHOWERS AND
THUNDERSTORMS MOVES ACROSS THROUGH THE DAY. IN FACT...THE AFTERNOON
INTO THE EVENING HOURS ALMOST LOOK LIKE FRONTOGENESIS NORTH OF A
SURFACE LOW WHICH IS TRACKING ACROSS SOUTHERN IOWA...I.E. A MORE
WINTER/SPRING LIKE APPEARANCE. THUS...RAISED PRECIPITATION CHANCES
WEDNESDAY AFTERNOON AND SHIFTED THE CHANCES FARTHER NORTH TO COME
INTO THE MODEL CONSENSUS. ALSO ENDED UP COOLING HIGHS ON WEDNESDAY
WITH POTENTIAL FOR MULTIPLE ROUNDS OF RAIN. THESE MAY NEED TO BE
COOLED FURTHER.
AFTER 06Z THURSDAY AND GOING THROUGH THE REST OF THE DAY THURSDAY...
THE FORECAST GETS EASIER. HIGH AMPLITUDE UPPER RIDGING IS PROGGED TO
BUILD UP THROUGH THE PLAINS AHEAD OF A DEEP TROUGH FORMING OVER THE
PACIFIC NORTHWEST. NORTHWEST FLOW DOWN THE UPPER RIDGE WILL HELP
KICK THE SHORTWAVE OVER CENTRAL IOWA AT 00Z THURSDAY
SOUTHEASTWARD...ALLOWING HIGH PRESSURE TO BUILD IN AND DRYING TO
OCCUR. THE NORTHWEST FLOW ALSO SENDS 850MB TEMPS DOWNWARD TO 10-12C
BY 18Z THURSDAY...THUS EXPECT COOLER BUT SEASONABLE WEATHER FOR
THURSDAY.
THURSDAY NIGHT THROUGH MONDAY...
10.12Z ECMWF/GFS/CANADIAN AND GFS ENSEMBLES CONTINUE TO SHOW THAT
THE DEEP PACIFIC NORTHWEST TROUGH IS GOING TO EJECT OUT ON FRIDAY
WHILE NEW TROUGHING REFORMS OFF THE PACIFIC NORTHWEST. AS THAT
PACIFIC NORTHWEST TROUGH LIFTS NORTHEASTWARD...IT PUSHES AND
FLATTENS THE AMPLIFIED RIDGE TOWARDS US. HIGH PRESSURE AHEAD OF THE
RIDGE SHOULD HELP KEEP THURSDAY NIGHT AND FRIDAY DRY...WITH ANY
CONVECTION GOING UP WELL TO THE WEST OVER THE DAKOTAS AND WESTERN IA
IN THE WARM ADVECTION ZONE. HEADING INTO FRIDAY NIGHT AND
SATURDAY...THAT WARM ADVECTION ZONE SHIFTS EAST WHICH WOULD PUSH THE
THREAT FOR CONVECTION INTO US. CONSENSUS CHANCES OF 60 WEST TO 20
EAST FRIDAY NIGHT AND 30-40 FOR SATURDAY SEEM REASONABLE.
HOWEVER...THERE IS GROWING AGREEMENT AMONGST MODELS OF AN MCS TO
FORM FRIDAY NIGHT OVER WESTERN IOWA...WHICH THEN DIVES SOUTHEAST ON
SATURDAY. IF THIS INDEED HAPPENS...THE PRECIPITATION CHANCES OVER US
COULD BE GREATLY REDUCED AS THE MCS TRAPS ANY MOISTURE TRANSPORT
TOWARDS US. BEYOND SATURDAY...A LOT OF UNCERTAINTY EXISTS WITH
HANDLING OF THAT EJECTING PACIFIC NORTHWEST TROUGH. THERE ARE SOME
SUGGESTIONS OF A COLD FRONT ASSOCIATED WITH IT APPROACHING THE AREA
ON SUNDAY PER 10.12Z CANADIAN/GFS...WHICH WOULD REQUIRE CHANCES FOR
SHOWERS AND THUNDERSTORMS...WHILE THE 10.12Z ECMWF STILL HAS THAT
FRONT BACK IN THE DAKOTAS KEEPING THE AREA DRY. THESE TWO MODEL
GROUPS BECOME REVERSED FOR SUNDAY NIGHT AND MONDAY WITH THE ECMWF
BRINGING THE FRONT IN AND THE CANADIAN/GFS HAVING IT SOUTH OF US.
THUS...BOTH SUNDAY AND MONDAY FEATURE 20-30 PERCENT CHANCES OF
SHOWERS AND THUNDERSTORMS. TEMPERATURES OVERALL LOOK AROUND NORMAL
WITH NO SIGNIFICANT WARM UP OR COOL DOWN BEING IN A MEAN NORTHWEST
TO WEST-NORTHWEST FLOW ALOFT.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1215 PM CDT MON JUN 10 2013
DIURNAL WARMING/MIXING AND INFLUX OF SOME DRIER AIR SLOWLY LIFTING/
ERODING THE LOWER CLOUD DECKS OVER THE FCST AREA THRU THE MORNING.
WITH RATHER LIGHT SFC-700MB GRADIENT WINDS...THIS PROCESS SLOW...
WITH SOME VFR/MVFR STRATO-CU CIGS LOOKING TO LINGER INTO THE MID
AFTERNOON HOURS. SFC-850MB RIDGE OF HIGH RIDGE OF HIGH PRESSURE TO
DRIFT EAST ACROSS THE AREA TONIGHT. DIVERGENCE/SUBSIDENCE IN THIS
RIDGE AXIS EXPECTED TO CONTINUE DECREASING THE STRATO-CU WITH SKIES
BECOMING CLEAR THIS EVENING. SFC RIDGE AXIS...LIGHT WINDS/ LEAR
SKIES AND THE MOIST BOUNDARY LAYER...SOME RADIATIONAL BR WITH MVFR
VSBYS EXPECTED TO FORM LATE TONIGHT/EARLY TUE MORNING. WILL HAVE TO
WATCH THIS FOR THE DECREASE OF CLOUDS BY LATER THIS AFTERNOON/EARLY
THIS EVENING. IF THE CLEARING IS DELAYED UNTIL LATE IN THE DAY...
AREA OF IFR VSBYS IN BR/FG POSSIBLE ACROSS THE FCST AREA...
ESPECIALLY IN THE MS AND LOWER WI RIVER VALLEYS. VFR CONDITION
EXPECTED TUE ONCE ANY BR/FG WOULD BURN OFF IN THE MORNING.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION.....RRS
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
1232 PM CDT MON JUN 10 2013
UPDATED AVIATION PORTION FOR 18Z TAF ISSUANCE
.SHORT TERM...TODAY...TONIGHT...AND TUESDAY
ISSUED AT 424 AM CDT MON JUN 10 2013
WV IMAGERY AND RAP ANALYSIS SHOWED AN UPPER LOW WEAKENING AS IT
MOVED ESE INTO CENTRAL IL. SCATTERED SHOWERS ASSOCIATED WITH ITS
DEFORMATION ZONE WERE ATTEMPTING TO WRAP BACK INTO OUR FAR SE
COUNTIES...BUT WERE DISSIPATING. STRONG ZONAL FLOW ALOFT WAS IN
PLACE FROM THE PACIFIC NW THROUGH MINNESOTA...WITH A WELL-DEFINED
S/W TROF AND 110 KT JET STREAK MOVG ALONG THE NORTH DAKOTA/CANADIAN
BORDER. THIS ENERGY APPEARED POISED TO CLIP NORTHERN WI LATER
TODAY. CLOUDS HAD SCATTERED OUT OVER MUCH OF GRB EARLY THIS
MORNING...AND PATCHY FOG WAS DEVELOPING.
PATCHY FOG SHOULD DISSIPATE QUICKLY BY MID-MORNING. SHOWERS
ASSOCIATED WITH THE DEPARTING UPPER SYSTEM ARE NOT EXPECTED TO
MAKE IT INTO OUR FAR SE COUNTIES EARLY TODAY...SO WILL NOT MENTION.
S/W TROF AND JET STREAK MOVG RAPIDLY THROUGH ND AND NW MN SHOULD
MOVE INTO N WI LATE THIS MORNING AND AFTERNOON...AND COMBINE WITH
DAYTIME HEATING AND WEAK LOW-LEVEL CONVERGENCE TO PRODUCE SCT
SHOWERS OVER MUCH OF THE FA. THE SHOWERS ARE EXPECTED TO MOST
NUMEROUS OVER NC/FAR NE WI...WHERE FORCING AND INSTABILITY (CAPE
300-400 J/KG) IS EXPECTED TO BE GREATEST. HAVE INCLUDED A MENTION
OF ISOLD TSTMS OVER THE FAR NORTH. CONSIDERED GOING WITH LIKELY
POPS OVER NORTHERN WI...BUT OPTED FOR HIGH CHANCE POPS INSTEAD...AS
THE 00Z ECMWF CAME IN WITH MUCH LESS QPF THAN ITS PREVIOUS RUN.
MIXING THROUGH 875-850 MB SUPPORTS HIGH TEMPS IN THE MIDDLE 70S
AWAY FROM LAKE MICHIGAN.
GENERALLY DRY CONDITIONS ARE EXPECTED ACROSS THE REGION TONIGHT...
WITH LIGHT WINDS AND PARTLY CLOUDY SKIES LEADING TO SOME FOG
DEVELOPMENT OVERNIGHT. EXPECT A MILD NIGHT...WITH MIN TEMPS IN THE
50S.
ON TUESDAY...ADDITIONAL SHORT-WAVE AND JET ENERGY WILL SKIM BY
TO OUR NORTH AS A WEAK/SHALLOW COLD FRONT DROPS INTO THE REGION.
HAVE CONTINUED WITH LOW POPS OVER NORTHERN WI...BUT POPS MAY NEED
TO BE EXPANDED OVER MORE OF THE FORECAST AREA WITH SUBSEQUENT
FCSTS. MIXING THROUGH 850-800 MB SUPPORTS A WARM DAY...WITH HIGHS
IN THE LOWER 80S.
.LONG TERM...TUESDAY NIGHT THROUGH SUNDAY
ISSUED AT 424 AM CDT MON JUN 10 2013
MODEL GUIDANCE CONTINUED TO FOCUS ON A MORE SOUTHERLY SOLUTION
FOR AN APPROACHING SHORT WAVE...SURFACE LOW PRESSURE SYSTEM AND
ASSOCIATED FRONTAL BOUNDARY FOR TUESDAY NIGHT AND WEDNESDAY. HAVE
GONE WITH A CHANCE OF SHOWERS AND THUNDERSTORMS FOR PARTS OF
CENTRAL AND EAST CENTRAL WISCONSIN AND LEFT THE NORTH DRY BECAUSE
OF THIS.
SURFACE HIGH PRESSURE AND AN UPPER LEVEL RIDGE ACROSS THE CENTRAL
CONUS SHOULD KEEP THURSDAY AND FRIDAY DRY...BEFORE THE NEXT SHORT
WAVE AND AN APPROACHING COLD FRONT BRING A CHANCE OF SHOWERS AND
THUNDERSTORMS BACK TO THE AREA FOR FRIDAY NIGHT AND SATURDAY.
PRECIPITATION MAY LINGER INTO SUNDAY SO HAVE LEFT SOME CHANCE POPS
IN FOR SATURDAY NIGHT AND SUNDAY AS WELL. TEMPERATURES SHOULD BE
WITHIN A FEW DEGREES OF NORMAL FOR MOST OF THE FORECAST PERIOD.
&&
.AVIATION...FOR 18Z TAF ISSUANCE
ISSUED AT 1232 PM CDT MON JUN 10 2013
MVFR/VFR CU FIELD FILLING IN OVER CNTRL WI WHERE
CLEARING HAD TAKEN PLACE EARLIER IN THE DAY. EXPECT THESE CLOUD
BASES TO RISE INTO THE 3-4K RANGE THIS AFTERNOON BEFORE GRADUALLY
DISSIPATING THIS EVENING WITH THE LOSS OF DAYTIME HEATING. A
STRATOCU FIELD LOCKED OVER ERN WI FOR MOST OF THE DAY SHOULD
BEGIN TO MIX OUT AS AN AREA OF LOW PRES OVER SW LWR MI PULLS
FARTHER AWAY. STILL CANNOT RULE OUT A FEW SHWRS SOMEWHERE OVER NE
WI AS DEW PTS ARE AROUND 60 DEGS. NE WI TO THEN SIT BETWEEN
SYSTEMS TNGT WITH SKIES ATTEMPTING TO CLEAR. IF THIS DOES HAPPEN
WITH LIGHT WIND/MOIST BOUNDARY LAYER REGIME...FOG WL DEVELOP AND
POTENTIALLY LOWER VSBYS TO AT LEAST MVFR CONDITIONS AND LOCALLY
IFR CIGS. EXPECT THIS FOG TO BURN OFF BY MID-MORNING TUE WITH VFR
CONDITIONS RETURNING.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM.....KIECKBUSCH
LONG TERM......MG
AVIATION.......AK
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
636 AM CDT MON JUN 10 2013
UPDATED AVIATION PORTION FOR 12Z TAF ISSUANCE
.SHORT TERM...TODAY...TONIGHT...AND TUESDAY
ISSUED AT 424 AM CDT MON JUN 10 2013
WV IMAGERY AND RAP ANALYSIS SHOWED AN UPPER LOW WEAKENING AS IT
MOVED ESE INTO CENTRAL IL. SCATTERED SHOWERS ASSOCIATED WITH ITS
DEFORMATION ZONE WERE ATTEMPTING TO WRAP BACK INTO OUR FAR SE
COUNTIES...BUT WERE DISSIPATING. STRONG ZONAL FLOW ALOFT WAS IN
PLACE FROM THE PACIFIC NW THROUGH MINNESOTA...WITH A WELL-DEFINED
S/W TROF AND 110 KT JET STREAK MOVG ALONG THE NORTH DAKOTA/CANADIAN
BORDER. THIS ENERGY APPEARED POISED TO CLIP NORTHERN WI LATER
TODAY. CLOUDS HAD SCATTERED OUT OVER MUCH OF GRB EARLY THIS
MORNING...AND PATCHY FOG WAS DEVELOPING.
PATCHY FOG SHOULD DISSIPATE QUICKLY BY MID-MORNING. SHOWERS
ASSOCIATED WITH THE DEPARTING UPPER SYSTEM ARE NOT EXPECTED TO
MAKE IT INTO OUR FAR SE COUNTIES EARLY TODAY...SO WILL NOT MENTION.
S/W TROF AND JET STREAK MOVG RAPIDLY THROUGH ND AND NW MN SHOULD
MOVE INTO N WI LATE THIS MORNING AND AFTERNOON...AND COMBINE WITH
DAYTIME HEATING AND WEAK LOW-LEVEL CONVERGENCE TO PRODUCE SCT
SHOWERS OVER MUCH OF THE FA. THE SHOWERS ARE EXPECTED TO MOST
NUMEROUS OVER NC/FAR NE WI...WHERE FORCING AND INSTABILITY (CAPE
300-400 J/KG) IS EXPECTED TO BE GREATEST. HAVE INCLUDED A MENTION
OF ISOLD TSTMS OVER THE FAR NORTH. CONSIDERED GOING WITH LIKELY
POPS OVER NORTHERN WI...BUT OPTED FOR HIGH CHANCE POPS INSTEAD...AS
THE 00Z ECMWF CAME IN WITH MUCH LESS QPF THAN ITS PREVIOUS RUN.
MIXING THROUGH 875-850 MB SUPPORTS HIGH TEMPS IN THE MIDDLE 70S
AWAY FROM LAKE MICHIGAN.
GENERALLY DRY CONDITIONS ARE EXPECTED ACROSS THE REGION TONIGHT...
WITH LIGHT WINDS AND PARTLY CLOUDY SKIES LEADING TO SOME FOG
DEVELOPMENT OVERNIGHT. EXPECT A MILD NIGHT...WITH MIN TEMPS IN THE
50S.
ON TUESDAY...ADDITIONAL SHORT-WAVE AND JET ENERGY WILL SKIM BY
TO OUR NORTH AS A WEAK/SHALLOW COLD FRONT DROPS INTO THE REGION.
HAVE CONTINUED WITH LOW POPS OVER NORTHERN WI...BUT POPS MAY NEED
TO BE EXPANDED OVER MORE OF THE FORECAST AREA WITH SUBSEQUENT
FCSTS. MIXING THROUGH 850-800 MB SUPPORTS A WARM DAY...WITH HIGHS
IN THE LOWER 80S.
.LONG TERM...TUESDAY NIGHT THROUGH SUNDAY
ISSUED AT 424 AM CDT MON JUN 10 2013
MODEL GUIDANCE CONTINUED TO FOCUS ON A MORE SOUTHERLY SOLUTION
FOR AN APPROACHING SHORT WAVE...SURFACE LOW PRESSURE SYSTEM AND
ASSOCIATED FRONTAL BOUNDARY FOR TUESDAY NIGHT AND WEDNESDAY. HAVE
GONE WITH A CHANCE OF SHOWERS AND THUNDERSTORMS FOR PARTS OF
CENTRAL AND EAST CENTRAL WISCONSIN AND LEFT THE NORTH DRY BECAUSE
OF THIS.
SURFACE HIGH PRESSURE AND AN UPPER LEVEL RIDGE ACROSS THE CENTRAL
CONUS SHOULD KEEP THURSDAY AND FRIDAY DRY...BEFORE THE NEXT SHORT
WAVE AND AN APPROACHING COLD FRONT BRING A CHANCE OF SHOWERS AND
THUNDERSTORMS BACK TO THE AREA FOR FRIDAY NIGHT AND SATURDAY.
PRECIPITATION MAY LINGER INTO SUNDAY SO HAVE LEFT SOME CHANCE POPS
IN FOR SATURDAY NIGHT AND SUNDAY AS WELL. TEMPERATURES SHOULD BE
WITHIN A FEW DEGREES OF NORMAL FOR MOST OF THE FORECAST PERIOD.
&&
.AVIATION...FOR 12Z TAF ISSUANCE
ISSUED AT 632 AM CDT MON JUN 10 2013
AREAS OF IFR/LIFR FOG IN NC/C WI WILL DISSIPATE BY 13Z-14Z...FOLLOWED
BY MAINLY VFR CONDITIONS FOR THE REST OF TODAY AND THIS EVG. SCT SHOWERS
WILL DEVELOP THIS AFTERNOON...ESPECIALLY OVER NC/FAR NE WI...WHERE ISOLD
TSTMS ARE ALSO EXPECTED. LIGHT WINDS...PARTLY CLOUDY SKIES AND LOW-LEVEL
MOISTURE SHOULD RESULT IN FOG DEVELOPMENT AGAIN LATE TONIGHT...WITH
VSBYS DROPPING TO IFR/LIFR IN SOME AREAS.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM.....KIECKBUSCH
LONG TERM......MG
AVIATION.......KIECKBUSCH
FORECAST DISCUSSION FOR ROUTINE MORNING FORECAST ISSUANCE
.SHORT TERM...TODAY...TONIGHT...AND TUESDAY
ISSUED AT 424 AM CDT MON JUN 10 2013
WV IMAGERY AND RAP ANALYSIS SHOWED AN UPPER LOW WEAKENING AS IT
MOVED ESE INTO CENTRAL IL. SCATTERED SHOWERS ASSOCIATED WITH ITS
DEFORMATION ZONE WERE ATTEMPTING TO WRAP BACK INTO OUR FAR SE
COUNTIES...BUT WERE DISSIPATING. STRONG ZONAL FLOW ALOFT WAS IN
PLACE FROM THE PACIFIC NW THROUGH MINNESOTA...WITH A WELL-DEFINED
S/W TROF AND 110 KT JET STREAK MOVG ALONG THE NORTH DAKOTA/CANADIAN
BORDER. THIS ENERGY APPEARED POISED TO CLIP NORTHERN WI LATER
TODAY. CLOUDS HAD SCATTERED OUT OVER MUCH OF GRB EARLY THIS
MORNING...AND PATCHY FOG WAS DEVELOPING.
PATCHY FOG SHOULD DISSIPATE QUICKLY BY MID-MORNING. SHOWERS
ASSOCIATED WITH THE DEPARTING UPPER SYSTEM ARE NOT EXPECTED TO
MAKE IT INTO OUR FAR SE COUNTIES EARLY TODAY...SO WILL NOT MENTION.
S/W TROF AND JET STREAK MOVG RAPIDLY THROUGH ND AND NW MN SHOULD
MOVE INTO N WI LATE THIS MORNING AND AFTERNOON...AND COMBINE WITH
DAYTIME HEATING AND WEAK LOW-LEVEL CONVERGENCE TO PRODUCE SCT
SHOWERS OVER MUCH OF THE FA. THE SHOWERS ARE EXPECTED TO MOST
NUMEROUS OVER NC/FAR NE WI...WHERE FORCING AND INSTABILITY (CAPE
300-400 J/KG) IS EXPECTED TO BE GREATEST. HAVE INCLUDED A MENTION
OF ISOLD TSTMS OVER THE FAR NORTH. CONSIDERED GOING WITH LIKELY
POPS OVER NORTHERN WI...BUT OPTED FOR HIGH CHANCE POPS INSTEAD...AS
THE 00Z ECMWF CAME IN WITH MUCH LESS QPF THAN ITS PREVIOUS RUN.
MIXING THROUGH 875-850 MB SUPPORTS HIGH TEMPS IN THE MIDDLE 70S
AWAY FROM LAKE MICHIGAN.
GENERALLY DRY CONDITIONS ARE EXPECTED ACROSS THE REGION TONIGHT...
WITH LIGHT WINDS AND PARTLY CLOUDY SKIES LEADING TO SOME FOG
DEVELOPMENT OVERNIGHT. EXPECT A MILD NIGHT...WITH MIN TEMPS IN THE
50S.
ON TUESDAY...ADDITIONAL SHORT-WAVE AND JET ENERGY WILL SKIM BY
TO OUR NORTH AS A WEAK/SHALLOW COLD FRONT DROPS INTO THE REGION.
HAVE CONTINUED WITH LOW POPS OVER NORTHERN WI...BUT POPS MAY NEED
TO BE EXPANDED OVER MORE OF THE FORECAST AREA WITH SUBSEQUENT
FCSTS. MIXING THROUGH 850-800 MB SUPPORTS A WARM DAY...WITH HIGHS
IN THE LOWER 80S.
.LONG TERM...TUESDAY NIGHT THROUGH SUNDAY
ISSUED AT 424 AM CDT MON JUN 10 2013
MODEL GUIDANCE CONTINUED TO FOCUS ON A MORE SOUTHERLY SOLUTION
FOR AN APPROACHING SHORT WAVE...SURFACE LOW PRESSURE SYSTEM AND
ASSOCIATED FRONTAL BOUNDARY FOR TUESDAY NIGHT AND WEDNESDAY. HAVE
GONE WITH A CHANCE OF SHOWERS AND THUNDERSTORMS FOR PARTS OF
CENTRAL AND EAST CENTRAL WISCONSIN AND LEFT THE NORTH DRY BECAUSE
OF THIS.
SURFACE HIGH PRESSURE AND AN UPPER LEVEL RIDGE ACROSS THE CENTRAL
CONUS SHOULD KEEP THURSDAY AND FRIDAY DRY...BEFORE THE NEXT SHORT
WAVE AND AN APPROACHING COLD FRONT BRING A CHANCE OF SHOWERS AND
THUNDERSTORMS BACK TO THE AREA FOR FRIDAY NIGHT AND SATURDAY.
PRECIPITATION MAY LINGER INTO SUNDAY SO HAVE LEFT SOME CHANCE POPS
IN FOR SATURDAY NIGHT AND SUNDAY AS WELL. TEMPERATURES SHOULD BE
WITHIN A FEW DEGREES OF NORMAL FOR MOST OF THE FORECAST PERIOD.
&&
.AVIATION...FOR 06Z TAF ISSUANCE
ISSUED AT 1150 PM CDT SUN JUN 9 2013
LOW PRESSURE WILL CONTINUE TO DRIFT ACROSS NORTHERN ILLINOIS
OVERNIGHT WITH SCATTERED SHOWERS ACROSS CENTRAL WISCONSIN
CONTINUING TO WANE. VFR CIGS WILL GRADUALLY DETERIORATE TO MVFR
FROM WEST TO EAST TOWARD DAYBREAK WITH SOME PATCHY FOG POSSIBLE
ESPECIALLY ACROSS CENTRAL WISCONSIN. SCATTERED SHOWERS ASSOCIATED
WITH SURFACE TROUGH WILL INCREASE IN COVERAGE ESPECIALLY ACROSS
THE NORTHEAST HALF OF THE FORECAST AREA BY LATE MORNING AND WILL
PERSIST INTO THE AFTERNOON UNTIL SURFACE TROUGH MOVES EAST OF THE
FORECAST AREA TOWARD EARLY EVENING. VFR CONDITIONS WILL RETURN
EARLY MONDAY EVENING AS WEAK HIGH PRESSURE MOVES INTO THE REGION.
SOME PATCHY FOG IS ALSO POSSIBLE TOWARD MIDNIGHT TUESDAY WITH
LIGHT WINDS...CLEARING SKIES AND RESIDUAL BOUNDARY LAYER MOISTURE
PERSISTING.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM.....KIECKBUSCH
LONG TERM......MG
AVIATION.......ESB
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
533 PM MDT TUE JUN 11 2013
.SHORT TERM...(TONIGHT THROUGH WEDNESDAY NIGHT)
ISSUED AT 405 PM MDT TUE JUN 11 2013
RADAR AND VISIBLE SATELLITE TRENDS SHOW CONVECTION TRYING TO
DEVELOP ALONG THE LEESIDE PRESSURE TROUGH/DRYLINE WHICH IS NOW
POSITIONED FROM EASTERN CONVERSE COUNTY IN WYOMING DOWN TO THE
SOUTHEAST IN CENTRAL KIMBALL COUNTY IN NEBRASKA. LAPS AND SPC MESO
ANALYSIS OF MLCAPE BOTH SHOW THE CAP ERODING JUST TO THE EAST OF
THIS BOUNDARY WITH A STRONGER CAP FURTHER EAST INTO NEBRASKA. 50+
KTS OF DEEP LAYER SHEAR IS BEING ANALYZED OVER THIS AREA AS
WELL...WITH LLVL SHEAR ON THE WEAK SIDE. STILL EXPECTING
CONVECTION TO STRENGTHEN AND INCREASE IN COVERAGE THROUGH THE LATE
AFTERNOON JUST EAST OF THE DRYLINE WHERE 1000 TO 1500 J/KG MLCAPE
IS IN PLACE WITH A SLOWLY WEAKENING CAP. RECENT RAP AND HRRR MODEL
RUNS AGREE WITH THE IDEA OF WIDELY SCATTERED SHOWERS AND STORMS LATE
THIS AFTERNOON AND EARLY EVENING MOVING EAST-NORTHEAST AHEAD OF
THE DRYLINE WITH LLVL SHEAR INCREASING MAINLY ACROSS THE NORTHERN
AND EASTERN PANHANDLE. AS A RESULT...WILL NOT MAKE ANY CHANGES TO
THIS MORNINGS UPDATE FOR A FEW STORMS TO BECOME SEVERE THROUGH
THIS EVENING...WITH THE HIGHEST POTENTIAL FOR SEVERE IN THE NORTHERN
PANHANDLE COUNTIES.
FURTHER WEST...WEST TO SOUTHWEST WINDS WILL CONTINUE TO GUST 35 TO
50 MPH AS THE UPPER LEVEL WAVE MOVES OVERHEAD THIS AFTERNOON AND
PUSHES THE LEESIDE PRESSURE TROUGH TO THE EAST. WINDS WILL
DIMINISH TONIGHT BEHIND A WEAK COOL FRONT MOVING SOUTH ACROSS THE
EASTERN PLAINS AFTER MIDNIGHT. A VERY MOIST BOUNDARY LAYER BEHIND
THE FRONT...COMBINED WITH ANY OUTFLOW FROM THIS EVENINGS
THUNDERSTORMS...WILL PRODUCE PATCHY AREAS OF FOG MAINLY IN LOW
LYING AREAS OF THE NEBRASKA PANHANDLE LATE TONIGHT AS SFC WINDS
DIMINISH.
SFC WINDS WILL SHIFT TO THE NORTH BEHIND THE FRONT TONIGHT...THEN
SOUTHEAST THROUGH WEDNESDAY AFTERNOON ACROSS THE EASTERN PLAINS WITH
CONTINUED BREEZY SOUTHWEST WINDS WEST OF THE LARAMIE RANGE. THE
UPPER LEVEL RIDGE WILL REBUILD OVER THE FORECAST AREA WITH A WEAK
PIECE OF ENERGY MOVING UP FROM THE SOUTHWEST IN THE LATER AFTERNOON.
A FEW STORMS COULD FIRE OVER THE LARAMIE RANGE AS SFC WINDS TURN TO
THE SOUTHEAST...ALTHOUGH COOLER SFC TEMPS BEHIND THE FRONT WILL KEEP
CONDITIONS MORE STABLE ACROSS THE EASTERN PLAINS. DECREASING WINDS
AND A CONTINUED MOIST BOUNDARY LAYER WILL ONCE AGAIN PRODUCE PATCHY
FOG OVER THE PANHANDLE ON WEDNESDAY NIGHT.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT PM MDT TUE JUN 11 2013
THE 12Z MODEL SOLUTIONS ARE REASONABLY CONSISTENT SHOWING THE UPPER
RIDGE SLOWLY TRANSLATING EASTWARD ACROSS THE GREAT PLAINS THURSDAY
AND FRIDAY. MEANWHILE...A TROUGH AND UPPER LOW OVER THE PACIFIC
NORTHWEST PIVOT EAST TO NORTHEAST THROUGH THE NORTHERN ROCKIES AND
INTO SOUTHERN CANADA INTO THE WEEKEND. THIS WILL FLATTEN THE RIDGE
OVER THE FRONT RANGE. A RIDGE AXIS THEN REBUILDS ALONG THE FRONT
RANGE AND ADJACENT PLAINS EARLY NEXT WEEK.
THE MAIN SURFACE WEATHER FEATURE OF THE LONG TERM WILL BE A MEANDERING
DRY LINE/TROUGH SEPARATING MOIST UNSTABLE AIR TO THE EAST FROM MUCH
DRIER AIR TO THE WEST. THIS BOUNDARY WILL BE DRIFTING EAST FROM THE
EASTERN WYOMING PLAINS INTO THE WESTERN PANHANDLE THURSDAY AS A
PACIFIC FRONT MOVES THROUGH THE CWFA LATE THURSDAY NIGHT AND FRIDAY
MORNING. ISOLATED CONVECTION WILL DEVELOP DURING THE EARLY AFTERNOON
ALONG THE LARAMIE RANGE AND MOVE EAST ONTO THE PLAINS FROM MID
AFTERNOON INTO THE EVENING. THIS FRONTAL PASSAGE WILL SHIFT WINDS
TO WESTERLY WITH DRIER AIR INFILTRATING MUCH OF THE REGION. THE
FRONT WILL STALL OVER WESTERN NEBRASKA FRIDAY AFTERNOON. WEAK
INSTABILITY AND SOME LOW LEVEL MOISTURE NEAR THE FRONT MAY TRIGGER A
FEW TSTORMS OVER THE SOUTHERN PANHANDLE FRIDAY AFTERNOON AND EARLY
EVENING. THE SURFACE TROUGH DRIFTS WEST INTO FAR SOUTHEAST WYOMING
SATURDAY AFTERNOON. LOW LEVEL CONVERGENCE NEAR THE LARAMIE RANGE MAY
TRIGGER ISOLATED TSTORMS. OTHERWISE...IT WILL REMAIN DRY. THE DRY LINE
DRIFTS EAST INTO THE WESTERN PANHANDLE WITH ISOLATED DIURNAL CONVECTION
POSSIBLE. BOTH MONDAY AND TUESDAY WILL FEATURE ISOLATED AFTERNOON AND
EVENING CONVECTION ALONG AND EAST OF THE LARAMIE RANGE.
TEMPERATURES THROUGHOUT THE LONG TERM WILL AVERAGE ABOVE SEASONAL
NORMALS. THURSDAY WILL BE THE WARMEST DAY WITH HIGHS FROM 85 TO 95.
FRIDAY AND SATURDAY WILL TREND SLIGHTLY COOLER WITH THE PASSAGE OF
THE PACIFIC FRONT. TEMPERATURES WARM SOMEWHAT SUNDAY THROUGH TUESDAY
WITH THE INFLUENCE FROM THE UPPER RIDGE.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY AFTERNOON)
ISSUED AT 519 PM MDT TUE JUN 11 2013
CONVECTION LOOKING MORE ACTIVE IN THE PANHANDLE EAST OF THE
DRYLINE THATS SET UP FROM PINE BLUFFS TO LUSK. CONTINUED THE VCTS
WORDING IN THE PANHANDLE TAFS THROUGH MID EVENING. WINDS SEEM TO
BE COMING DOWN SOME LOOKING AT AREA METARS...BUT WILL STILL BE
STRONG THROUGH SUNSET. DRYLINE DOES NOT MOVE TOO FAR EAST
OVERNIGHT WITH EAST TO NORTHEAST FLOWA CROSS THE PANHANDLE. BEST
CHANCES FOR MVFR/IFR CEILINGS STILL LOOKS TO BE THE NORTHERN
PANHANDLE AND PARTICULARLY KCDR.
&&
.FIRE WEATHER...
ISSUED AT 405 PM MDT TUE JUN 11 2013
A WEATHER DISTURBANCE MOVING TOWARD THE DISTRICT
TODAY WILL BRING A CHANCE FOR THUNDERSTORMS ACROSS THE
EASTCENTRAL PLAINS OF WYOMING AND THE NEBRASKA PANHANDLE THIS
AFTERNOON AND EVENING. STRONG WINDS...LIGHT TO MODERATE RAIN...AND
SOME HAIL WILL OCCUR WITH THESE THUNDERSTORMS.
GUSTY WEST TO SOUTHWEST WINDS AND DRY CONDITIONS WILL CONTINUE
THROUGH THIS EVENING ALONG AND WEST OF THE LARAMIE RANGE WHERE
HUMIDITIES HAVE DROPPED TO BETWEEN 6 AND 14 PERCENT AND WINDS ARE
GUSTING 35 TO 45 MPH THIS AFTERNOON. WINDS WILL EASE AND
HUMIDITIES WILL RECOVER TO BETWEEN 30 AND 50 PERCENT TONIGHT. A
RIDGE OF HIGH PRESSURE WILL BUILD OVER THE DISTRICT ON WEDNESDAY
AND THURSDAY...AND SO MOSTLY DRY AND WARM TEMPERATURES WILL
CONTINUE THROUGH THIS TIME. HUMIDITIES WILL REMAIN IN THE TEENS TO
LOW 20S IN SOUTHEAST WYOMING...WITH 20 TO 30 PERCENT EXPECTED IN
THE NEBRASKA PANHANDLE. WINDS WILL REMAIN ON THE WINDY SIDE ALONG
AND WEST OF THE LARAMIE RANGE THROUGH THIS TIME AS WELL...WITH
GUSTS OF 30 TO 40 MPH COMMON IN THE AFTERNOON EACH DAY. FURTHER
EAST...WINDS WILL BE OUT OF THE SOUTHEAST AND WILL GUST 20 TO 30
MPH IN THE AFTERNOON.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&
$$
SHORT TERM...RJM
LONG TERM...MAJ
AVIATION...CLAYCOMB
FIRE WEATHER...RJM
AREA FORECAST DISCUSSION
NWS TALLAHASSEE FL
442 AM EDT Wed Jun 12 2013
.NEAR TERM [Through Tonight]...
With upper level ridging continuing to nose in from the west, SFC
ridging parked just to our south, and NW synoptic flow at the lower
levels, plenty of daytime insolation should allow for one of the
hottest days of the season thus far. High temps are expected to
climb into the upper 90s over much of the interior, with lower 90s
restricted to the immediate coast. In fact, the usual hot spots like
Valdosta may experience their first 100 degree day this year. Heat
indices will also be on the rise, but afternoon dewpoints should mix
out enough to keep them below Advisory levels. Nevertheless,
maximum Heat Indices of around 105 degrees will be quite
uncomfortable. As for rain chances, the 1000-700mb Mean Layer Vector
Wind (MLVW) will be out of the NW today, which is a Type 8 Regime in
our local Sea Breeze Climatology (reference
www.srh.noaa.gov/tae/?n=seabreeze for details). In short, this
Regime tends to keep the Sea Breeze Front pinned near the coastline
until later in the afternoon, but also increases vertical motion
along the front, which can result in stronger storms given a
favorable environment. For this afternoon, we are only forecasting
20% PoPs across much of the FL Big Bend and Panhandle (with silent
10s elsewhere), which is essentially a blend of our local Confidence
Grids and CAM (Convective Allowing Models) output. These PoPs are
also lower than a typical Type 8 Regime due to less favorable deep
layer thermodynamics. However, any storms that do develop may
contain brief gusty winds. For tonight, did not carry over any PoPs
at this time, although this always carries some risk in Regime 8 due
to the usual late start of the convection. Additionally, some of the
Hi-Res models are hinting at potential MCS development to our N and
NE which will have to be monitored as well.
&&
.SHORT TERM [Thursday Through Friday Night]...
The main focus for the short term period will be the potential for
severe weather in our CWA. The SPC Day 2 Outlook has our far
northern Florida counties and all of our Georgia and Alabama
counties under a slight risk, but our entire CWA is under at least
a 5% probability of severe weather.
Deep layer ridging to the west and troughing to the east will
continue to keep our CWA in a northwest flow regime. Northwest
flow will keep our entire CWA drier than average and warmer than
average. A shortwave is expected round the base of the trough and
pivot through our area beginning Friday morning. This type of
synoptic pattern is conducive for MCS development/maintenance. Low
level CAPE and shear values seem conducive for new cell
development to maintain multicellular thunderstorm complexes. The
advancing afternoon sea breeze of Friday will also likely enhance
any thunderstorms that are present.
Other than the chance for severe weather the remaining short term
period will be characterized by above average temperatures, below
averages humidities, and low chances for rain.
&&
.LONG TERM [Saturday through Wednesday]...
Continuing from the short term, we have a frontal system possibly
reaching our area around Thursday night and exiting to the southeast
by overnight Friday night. Rain chances will stay low once again
thanks to high pressure aloft and at the surface, although some
convection from the sea-breeze may be possible. Monday through
Tuesday rain chances increase again as another shortwave moves
through with a similar setup to the Thursday-Friday rain chances.
Highs in the 90s and lows in the 70s are expected through the period.
&&
.AVIATION...
[Through 12 UTC Thursday] With the recent influx of drier air from
the northwest, VFR conditions should prevail at the terminals
through the period. However, did go with brief periods of low end
MVFR Cigs at ECP and TLH (based on input from the HRRR guidance)
overnight and a period of MVFR level Vis at VLD. During the day,
isolated afternoon thunderstorms will again be possible with the Sea
Breeze Front, but PoPs are too low for mention in any of the Tafs at
this time. That said, with the northwesterly flow, the best chances
for an afternoon storm would be at ECP and TLH.
&&
.MARINE...
Light winds and relatively calm seas are expected until a frontal
system approaches to our north beginning late Thursday night/early
Friday morning when cautionary levels will be possible. By Friday
night, winds are expected to weaken to below cautionary levels.
&&
.FIRE WEATHER...
Although the generally hot and dry weather will continue, conditions
are not expected to approach Red Flag levels over the next several
days.
&&
.HYDROLOGY...
After the recent heavy rainfall across the area, two river points
are at or expected to reach Action Stage. The Ochlockonee River near
Thomasville is at Action stage, and will crest early Friday morning
then start to recede. The Little River near Hahira is expected to
reach Action Stage early Monday morning. With little precipitation
expected over the next couple of days, impacts to area rivers will
be minimal.
&&
.PRELIMINARY POINT TEMPS/POPS...
Tallahassee 98 72 96 74 94 / 20 10 20 20 30
Panama City 92 76 91 78 91 / 20 10 20 20 30
Dothan 98 74 99 74 95 / 10 10 10 20 20
Albany 98 74 99 74 93 / 10 10 10 30 20
Valdosta 100 72 99 73 92 / 10 10 20 30 30
Cross City 95 72 93 74 91 / 20 10 20 10 30
Apalachicola 91 75 89 77 90 / 20 10 10 10 30
&&
.TAE WATCHES/WARNINGS/ADVISORIES...
FL...None.
GA...None.
AL...None.
GM...None.
&&
$$
NEAR TERM...Gould
SHORT TERM...Navarro/Harrigan
LONG TERM...Moore
AVIATION...Gould
MARINE...Navarro/Harrigan
FIRE WEATHER...Navarro/Harrigan
HYDROLOGY...Navarro/Harrigan
AREA FORECAST DISCUSSION
NWS MIAMI FL
320 AM EDT WED JUN 12 2013
.SHORT TERM (TODAY-FRIDAY)...
THE LATEST MODEL GUIDANCE INDICATES THE UPPER LEVEL PATTERN BECOMING
MORE AMPLIFIED ACROSS THE COUNTRY BY THE END OF THE SHORT-TERM
PERIOD AS SEVERAL SHORTWAVE TROUGHS DIG SOUTHEAST FROM THE GREAT
LAKES TO THE SOUTHEAST AND AN UPPER RIDGE BUILDS OVER THE MID-WEST.
AT THE SURFACE...THE LOCAL AREA WILL REMAIN IN A WEAKNESS WITHIN THE
SUBTROPICAL RIDGE WITH WEAK LOW-LEVEL STEERING FLOW CONTINUING. A
WEAK FRONTAL BOUNDARY ASSOCIATED WITH A SHORTWAVE TROUGH IS FORECAST
TO SAG SOUTH OVER THE STATE BY THE END OF THE PERIOD.
FOR TODAY...THE WEAK LOW-LEVEL FLOW COMBINED WITH A SUFFICIENT
AMOUNT OF MOISTURE AND INCREASING INSTABILITY DUE TO COOLER
MID/UPPER LEVEL TEMPERATURES (H5 -10 C INLAND) SPREADING SOUTH OVER
THE AREA WILL LIKELY TRANSLATE TO ANOTHER ROUND OF SCATTERED SHOWERS
AND STORMS THIS AFTERNOON. A FEW OF THESE STORMS MAY BECOME STRONG
WITH THE MAIN THREATS BEING GUSTY WINDS AND HAIL.
ADDITIONALLY...WITH THE WEAK STEERING FLOW IN PLACE AND VERY
LITTLE STORM MOTION WITH THE ACTIVITY THAT DOES DEVELOP COULD LEAD
TO LOCALIZED FLOODING. ALTHOUGH THE HI-RES MODEL REFLECTIVITIES
DISPLAY QUITE THE SPREAD AS TO WHERE THE AFTERNOON CONVECTION WILL
BECOME CONCENTRATED...THE MORE RELIABLE HRRR SOLUTION GENERALLY
INDICATES THE BULK OF THIS ACTIVITY SETTING UP OVER THE INTERIOR
AREAS BEGINNING AROUND 16-19Z.
THURSDAY THROUGH FRIDAY...ALTHOUGH SIMILAR CONDITIONS WILL
PERSIST...MID-LEVEL TEMPERATURES ARE FORECAST TO WARM BACK TO AROUND
OR JUST ABOVE AVERAGE. PRECIPITABLE WATER VALUES ARE ALSO FORECAST
TO TREND DOWNWARD TOWARD 1.5". THE SFC RIDGE IS FORECAST TO STEADILY
SHIFT SOUTHWARD...WHICH WILL LEAD TO LIGHT SWRLY LOW-LEVEL FLOW
AHEAD OF THE AFOREMENTIONED FRONTAL BOUNDARY SAGGING SOUTH INTO THE
STATE BY FRIDAY AFTERNOON. DESPITE THE MORE STABLE AND SLIGHTLY
DRIER CONDITIONS...AFTERNOON SHOWERS/TSTMS...MAINLY ISOLATED IN
COVERAGE...MAY FAVOR THE EAST COAST METRO AREAS WITH THE SW FLOW
SETTING UP THROUGH THIS TIME.
.LONG TERM (FRIDAY NIGHT-TUESDAY)...
THE MODELS GENERALLY INDICATE RISING UPPER HEIGHTS ALONG WITH SOME
DRIER MID/UPPER AIR OVER THE WEEKEND. HIGH PRESSURE BUILDING EAST
NORTH OF THE AREA IN THE WAKE OF THE PREVIOUSLY DISCUSSED FRONTAL
BOUNDARY WILL LEAD TO EASTERLY LOW-LEVEL FLOW RETURNING ACROSS THE
AREA. PRECIPITABLE WATER VALUES ARE FORECAST TO DIP DOWN BELOW 1.25"
THROUGH THE WEEKEND AND INTO MONDAY. THIS WILL LEAD TO DRIER AND
WARMER CONDITIONS ACROSS THE AREA. ANY AFTERNOON SHOWERS THAT
DEVELOP SHOULD REMAIN INLAND WITH THE EASTERLY FLOW SETTING UP.
&&
.AVIATION...
WINDS ARE EXPECTED TO BE LIGHT AND VARIABLE ACROSS THE AREA THROUGH
THE EARLY TO MID MORNING HOURS BEFORE TURNING MORE EASTERLY ACROSS
THE EAST COAST TERMINALS. FLOW WILL AGAIN BE RATHER WEAK ALLOWING
FOR GOOD CONVERGENCE WITH THE GULF BREEZE. EXPECT SCATTERED
SHRAS/TSRAS MAINLY ACROSS INTERIOR AREAS BUT COULD APPROACH ALL TAF
SITES LATE IN THE AFTERNOON. KEPT VCTS MENTION FOR NOW. ISOLATED IFR
CONDITIONS WILL BE POSSIBLE WITH ANY TSRA THAT AFFECTS ANY TAF SITE.
&&
.MARINE...
HIGH PRESSURE RIDGE WILL STEADILY SHIFT SOUTH OVER THE MARINE AREA
THROUGH THE END OF THE WEEK AS A WEAK FRONTAL BOUNDARY APPROACHES
FROM THE NORTH. AS A RESULT...LIGHT WINDS AND LOW SEAS WILL BE
EXPECTED TO CONTINUE.
&&
.FIRE WEATHER...
PLENTY OF MOISTURE WILL KEEP THE RH VALUES WELL ABOVE CRITICAL
LEVELS EACH DAY.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 89 76 89 76 / 20 20 20 20
FORT LAUDERDALE 88 77 89 76 / 20 20 20 20
MIAMI 89 77 90 75 / 20 20 20 20
NAPLES 89 74 88 74 / 20 20 20 20
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
DISCUSSION/MARINE/FIRE...85/AG
AVIATION/RADAR...10/CD
AREA FORECAST DISCUSSION
NWS PEACHTREE CITY GA
405 AM EDT WED JUN 12 2013
.SHORT TERM /TODAY THROUGH THURSDAY/...
ANOTHER HOT DAY ACROSS THE CWA AS THE AREA REMAINS UNDER THE EASTERN
EDGE OF AN UPPER LEVEL RIDGE. SOME DECENT UNCERTAINTY IN THE POP
FORECAST FOR TODAY. GFS SHOWS A STRONG VORT MAX ROUNDING THE UPPER
LEVEL RIDGE AND BRINGS IT INTO NORTH GEORGIA BY MID MORNING. GFS
ISNT GENERATING MUCH IN TERMS OF PRECIP WITH IT THOUGH ACROSS THE
CWA. NAM SHOWS SOME REFLECTION OF A SHORTWAVE BUT IS WEAKER AND
GENERALLY FURTHER EAST. EVEN HARDER TO PICK OUT THE FEATURE IN THE
ECMWF. DESPITE THIS THOUGH...ECMWF AND NAM ARE THE HIGHEST IN TERMS
OF PRECIP CHANCES ACROSS NORTH GEORGIA TODAY. HRRR IS PICKING UP ON
SOME ACTIVITY IN NORTH GEORGIA ASSOCIATED WITH THIS. FOR THE
FORECAST TRIED TO MEET IN THE MIDDLE AND HAVE SHOWN SLIGHT CHANCE OF
SHOWERS AND THUNDERSTORMS ACROSS THE NORTH. LEE SIDE TROUGH APPEARS
IT SHOULD BE JUST SOUTH OF THE CWA THIS AFTERNOON AND IF SOMETHING
WERE TO DEVELOP...THINK IT SHOULD BE ALONG THIS BOUNDARY...SO KEPT
MENTION OF POPS OUT OF CENTRAL GEORGIA.
THURSDAY IS THE BETTER CHANCE OF RAIN IN THE SHORT TERM AS A STRONG
SHORTWAVE MOVES FROM THE OHIO VALLEY INTO THE MID ATLANTIC AND A
COLD FRONT MOVES INTO GEORGIA. MODELS ARE IN GOOD AGREEMENT WITH THE
COLD FRONT MOVING INTO THE NORTH THURSDAY MORNING AND INTO CENTRAL
GEORGIA BY THE EVENING. DECENT INSTABILITY WITH THE SYSTEM WITH THE
GFS SHOWING ML CAPE AROUND 2000 J/KG. LL SHEAR IS NON-ZERO WITH
AROUND 20KTS ACROSS CENTRAL GEORGIA. WITH THE INSTABILITY...A
BOUNDARY TO FOCUS ON AND UPPER LEVEL SUPPORT...ISOLD SEVERE STORMS
ARE POSSIBLE ON THURSDAY WITH THE MAIN THREATS BEING WIND AND HAIL.
TOTAL RAINFALL AMOUNTS SHOULD BE MINIMAL...AROUND A QUARTER INCH OR
LESS WITH LOCALLY HIGHER AMOUNTS IN SOME OF THE THUNDERSTORMS.
BOTH AHN AND ATL SAW THEIR FIRST 90 DEGREE DAY FOR THE YEAR
YESTERDAY AND ALL OF NORTH AND CENTRAL GEORGIA IS EXPECTED TO REACH
THE LOW TO MID 90S AGAIN TODAY EXCEPT FOR THE MOUNTAINS. EVEN WITH
THE FRONT EXPECTED ON THURSDAY...MOST PLACES WILL HAVE TIME AHEAD OF
THE RAIN TO REACH THE 90S AGAIN. SOME OF CENTRAL GEORGIA WILL REACH
HEAT INDICES OF 100-102 THIS AFTERNOON WHICH FALLS SHORT OF A HEAT
ADVISORY /105 DEGREES OR GREATER HEAT INDICES FOR TWO CONSECUTIVE
DAYS/...BUT IT WILL STILL BE HOT AND FOLKS SHOULD KEEP THIS IN MIND
WHEN WORKING OUTSIDE AS ITS EXPECTED TO BE THE HOTTEST DAY OF THE
SEASON SO FAR.
11
.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
A COLD FRONT WILL BE CLOSE TO CENTRAL GA AND MOVING S STARTING
THURSDAY NIGHT WITH POTENTIAL FOR SEVERE STORMS ASSOCIATED. THE
FRONT EXITS THE FORECAST AREA LATER THURSDAY NIGHT WITH THE GFS THE
FASTEST...THE NAM NEXT AND THE EUROPEAN THE SLOWEST.
PRECIP CHANCES MOST LIKELY WILL HAVE ENDED FOR FRIDAY ALTHOUGH THE
EUROPEAN HOLDS ONTO CHANCES OVER CENTRAL GA. SATURDAY IS DRY AS HIGH
PRESSURE ALOFT OVER THE LOWER MS VALLEY HELPS FOR HOLD ANY
CONVECTION AT BAY...HOWEVER NW FLOW ALOFT IS OVER THE AREA BUT
APPEARS TO HAVE ONLY MINIMAL MOISTURE. SUNDAY APPEARS ONE OF THOSE
DAYS WHERE YOU COULD GO EITHER WAY WITH 20 PERCENT POPS OVER THE NW
HALF OR SO OF THE AREA AS THE UPPER RIDGE FLATTENS AND SOME
INSTABILITY DEVELOPS WITH MINIMAL MOISTURE. FOR NOW WILL JUST HOLD
ONTO 10 PERCENT ACROSS THE NW. THE SOUTHERN EDGE OF THE WESTERLIES
RETURN FOR MONDAY AND TUESDAY WITH INCREASED MOISTURE AND INSTABILITY
ACROSS THE AREA AND THE POSSIBILITY FOR SHORT WAVES TO ENHANCE THE
POTENTIAL FOR SCATTERED SHOWERS AND THUNDERSTORMS. A WEAK COLD FRONT
MAY GET INTO N GA FOR WEDNESDAY.
BDL
&&
.AVIATION...
06Z UPDATE...
MOSTLY HIGH CLOUDS ACROSS THE AREA TONIGHT AND WILL SEE SOME CU
DEVELOP THIS AFTERNOON. FOG EXPECTED TO DEVELOP THIS MORNING
BRINGING SOME VSBYS DOWN TO MVFR BUT WILL ONLY BE A FEW HOURS IN
DURATION. WITH A SHORTWAVE MOVING INTO NORTHEAST GEORGIA
TODAY...COULD SEE ISOLD TSRA DEVELOPMENT...BUT EXPECT IT TO REMAIN
NORTH OF THE TAF SITES. IF SOMETHING WERE TO DEVELOP AND PUSH
SOUTHEAST...AHN HAS THE BEST CHANCE OF SEEING A THUNDERSTORM OF
ALL THE TAF SITES.
//ATL CONFIDENCE...06Z UPDATE...
HIGH CONFIDENCE ON ALL ELEMENTS.
11
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 95 70 94 67 / 20 10 50 20
ATLANTA 92 74 92 68 / 10 10 50 30
BLAIRSVILLE 88 67 86 59 / 20 20 50 20
CARTERSVILLE 93 70 93 65 / 10 10 50 20
COLUMBUS 95 75 96 73 / 10 10 20 40
GAINESVILLE 91 72 91 66 / 20 20 50 20
MACON 95 71 96 69 / 10 10 20 40
ROME 94 70 92 66 / 20 10 50 10
PEACHTREE CITY 92 69 93 67 / 10 10 50 30
VIDALIA 96 75 97 73 / 10 5 20 40
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...11
LONG TERM....BDL
AVIATION...11
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
229 AM CDT WED JUN 12 2013
.DISCUSSION...
834 PM CDT
A FEW THOUGHTS REGARDING THE THUNDERSTORM THREAT OVERNIGHT AND THE
MODERATE RISK FOR SEVERE WEATHER WEDNESDAY...
THIS EVENING...A WARM FRONT EXTENDS FROM WESTERN IOWA EAST TOWARDS
IOWA CITY...THEN LOSES ITS DEFINITION SOUTHEAST INTO CENTRAL
ILLINOIS. LOW TO MID 70 DEW POINTS ARE POOLING ALONG THE BOUNDARY
TO OUR WEST...BUT AS A 20Z SOUNDING OUT OF DVN SHOWED...A STRONG
CAP IS IN PLACE WITH 825MB TEMPS AROUND 21C. LATEST RAP GUIDANCE
INDICATES THE THE CAP WILL REMAIN IN PLACE THROUGH THE REMAINDER
OF THE EVENING AND TONIGHT. WITH THAT SAID....THE THREAT FOR
SEVERE WEATHER THROUGH THE REMAINDER OF TODAY HAS GREATLY
DIMINISHED. FOCUS TURNS OUT TO THE WEST TONIGHT WHERE A 50-60KT
LOW LEVEL JET IS EXPECTED TO DEVELOP WITH THE BEST MOISTURE
CONVERGENCE FOCUSED OVER CENTRAL NEBRASKA...AND BY MIDNIGHT
TONIGHT SLIGHTLY FARTHER EAST OVER THE MID MISSOURI VALLEY.
DESPITE THE FOCUS BEING WELL OFF TO OUR WEST...THERE IS SOME
ASCENT ALONG THE WARM FRONT SO CAN NOT RULE OUT SOMETHING TRYING
TO DEVELOP THIS EVENING NORTH OF THE WARM FRONT AND MOVING INTO
NORTHERN ILLINOIS...BUT EXPECT COVERAGE TO BE LOW AWAY FROM THE
BETTER FORCING WITH THE LLJ. WITH THAT IN MIND...LOWERED POPS
ACROSS MUCH OF THE CWA FOR THE OVERNIGHT HOURS AND FEEL THEY MAY
STILL BE ON THE HIGH END. CONVECTIVE ALLOWING MODELS STILL SHOW
AN MCS DEVELOPING AT THE NOSE OF THE LLJ TONIGHT...AND BY
DAYBREAK TOMORROW POSSIBLY MOVING INTO NORTHWESTERN ILLINOIS...
BUT MORE LIKELY STAYING NORTH OF THE STATE LINE. EITHER WAY...LLJ
IS VEERING AND WEAKENING BY THAT TIME SO CONVECTION SHOULD BE IN
A WEAKENING PHASE.
THE STORM PREDICTION CENTER CONTINUES TO CARRY US UNDER A MODERATE
RISK WEDNESDAY AND THIS SEEMS TO BE ON TRACK. APPEARS WE WILL BE
UNDER A PRETTY DYNAMIC ENVIRONMENT TOMORROW AS A COUPLED JET SETS
UP WITH THE BEST UPPER LEVEL DIVERGENCE OVER CENTRAL AND NORTHERN
ILLINOIS. MODERATE HEIGHT FALLS ASSOCIATED WITH THE MID LEVEL WAVE
MOVING INTO THE AREA LATE AFTERNOON/EARLY EVENING TOMORROW WILL
PROVIDE LARGE SCALE ASCENT ACROSS THE AREA TO HELP WEAKEN THE CAP.
THE SURFACE LOW TRACKS EAST ACROSS THE MISSISSIPPI VALLEY JUST
SOUTH OF MLI...THOUGH THERE ARE SOME MODELS SUGGESTING THE LOW
TRACK AND RESULTING SEVERE THREAT MAY TRACK SLIGHTLY FARTHER
NORTH. SOME MODELS ALSO INDICATE THE LOW DEEPENING SLIGHTLY
TOMORROW AFTERNOON WITH 2-4MB PRESSURE FALLS OVERSPREADING AREAS
SOUTH OF I-80. THIS WILL ONLY HELP TO ENHANCE WHAT ALREADY LOOKS
TO BE PRETTY STRONG LOW LEVEL HELICITY TOMORROW. DEEP LAYER SHEAR
TOMORROW IS ALSO FORECAST TO BE QUITE STRONG. ALL SAID THERE IS
CONCERN FOR DISCRETE SUPER CELLS DEVELOPING IN THE AFTERNOON WITH
THE WHOLE GAMUT OF SEVERE WEATHER POSSIBLE...LARGE HAIL...
DAMAGING WINDS AND QUITE POSSIBLY TORNADOES. STORMS SHOULD
EVENTUALLY CONGEAL INTO A LINE WITH THE MAIN THREAT TURNING
BECOMING DAMAGING WINDS...THOUGH QLCS TORNADOES WILL STILL BE A
CONCERN. HOW QUICKLY WE TRANSITION FROM DISCRETE SUPER CELLS TO A
LINEAR MCS IS UNCERTAIN. INTERESTING TO NOTE THAT ONE OF THE TOP
CIPS ANALOGS IS JUNE 05 2010 WHICH DID HAVE DISCRETE SUPER CELLS
WITH TORNADOES LATER INTO THE EVENING.
DEUBELBEISS
//PREV DISCUSSION...
300 PM CDT
MAIN FORECAST CONCERNS/CHALLENGES IN THE NEAR TERM ARE WITH
MULTIPLE ROUNDS OF CONVECTION POSSIBLE ACROSS THE ENTIRE CWA
TONIGHT THROUGH WEDNESDAY NIGHT WITH SEVERE WEATHER NOT OUT OF
THE QUESTION THIS EVENING AND OVERNIGHT...BUT WITH A MORE
SIGNIFICANT SEVERE WEATHER OUTBREAK BECOMING INCREASINGLY MORE
POSSIBLE ACROSS A PORTION OF THE CWA ON WEDNESDAY.
IN THE NEAR TERM...CONTINUE TO MONITOR CONVECTION DEVELOPING JUST
SOUTHWEST/SOUTH OF THE CWA AT THIS TIME AS A MID LEVEL IMPULSE
SLIDES EAST ACROSS THE AREA AND ENCOUNTERS SOME WEAK LOW/MID
LEVEL CONVERGENCE IN AND AROUND SHIFTING SURFACE TROUGH ACROSS
IOWA. THIS AREA OF CONVECTION SHOULD CONTINUE EAST/SOUTHEAST WITH
TIME FOR THE REMAINDER OF THE AFTERNOON MAINLY ONLY AFFECTING
AREAS FROM LA SALLE IN ILLINOIS SOUTHEAST TO RENSSELAER IN
INDIANA...SUPPORTED BY THIS WAVE AND CURRENT WAA IN PLACE.
ALTHOUGH INSTABILITY REMAINS RATHER WEAK ACROSS THESE AREAS AS
WELL AS CIN IN PLACE...LATEST TRENDS SUPPORT A NORTHEASTWARD
EXPANSION OF THE INSTABILITY AXIS AS WELL AS WEAKENING CIN.
DESPITE WEAKLY FORCED...THESE CONDITIONS COINCIDING WITH
SUFFICIENT BULK SHEAR COULD SUPPORT AN ISOLATED HAIL/WIND THREAT
THROUGH LATE AFTERNOON. GOING INTO THE EARLY EVENING...COULD SEE
A DRY PERIOD FOR MOST OF NORTHERN ILLINOIS AND NORTHWEST INDIANA
BUT WITH THE POSSIBILITY FOR AN INCREASE IN COVERAGE OF
THUNDERSTORMS ONCE AGAIN LATER IN THE EVENING. THIS IS A DEFINITE
POSSIBILITY ESPECIALLY AS SEVERAL MID LEVEL FEATURES/SPEED MAXES
ARE ANTICIPATED TO ROUND THE MID LEVEL RIDGE...AS WELL AS A
VEERING LLJ STRENGTHENS THIS EVENING.
CONTINUE TO MONITOR THESE MID LEVEL FEATURES TRACKING EAST ACROSS
THE CENTRAL AND NORTHERN PLAINS ON LATEST VISIBLE
SATELLITE...TRYING TO GRAB A HANDLE ON THIS POSSIBILITY OF
INCREASED CHANCES FOR CONVECTION LATER THIS EVENING. THIS IS DUE
TO MOST GUIDANCE VARYING TO SOME DEGREE ON PLACEMENT AS WELL AS
TIMING THIS EVENING...WITH CONFIDENCE NOT THE GREATEST FOR
CONVECTIVE EVOLUTION THIS EVENING. ALTHOUGH LATEST THOUGHTS FOR
THIS EVENING ONCE AGAIN DO INCLUDE THE POSSIBILITY FOR AN
INCREASED CHANCE FOR THUNDERSTORMS AS WELL AS THE POSSIBILITY FOR
SEVERE WEATHER...DAMAGING WINDS AND HAIL ONCE AGAIN THE MAIN
THREATS. MID LEVEL FEATURE MOVING OUT OF THE CENTRAL PLAINS
SHOULD ENCOUNTER STRONG LOW/MID LEVEL CONVERGENCE IN IOWA...AND
SHOULD THEN SEE AN UP-GROWTH IN CONVECTION ACROSS EASTERN IOWA
JUST AFTER THE 7PM TIME FRAME. LATEST GUIDANCE IS SHOWING THAT
THE CURRENT NORTHEASTWARD EXPANSION OF THIS INSTABILITY AXIS WILL
CONTINUE THIS EVENING AND ORIENT ITSELF ACROSS NORTH CENTRAL/EAST
CENTRAL ILLINOIS. THIS INCREASED INSTABILITY AS WELL AS
SUFFICIENT 0-3/0-6KM BULK SHEAR THIS EVENING LENDS ITSELF TO
SUPPORT A POSSIBLE WIND THREAT ACROSS NORTH CENTRAL...NORTHEAST
ILLINOIS...AS WELL AS NORTHWEST INDIANA AROUND THE 9PM TIME FRAME.
ANY DEVELOPMENT IS THEN EXPECTED TO SHIFT SOUTHEAST OF THE CWA
AFTER THE MIDNIGHT TIME FRAME...BUT THUNDERSTORMS STILL NOT BE
OUT OF THE QUESTION AFTER MIDNIGHT. PERSISTENT WAA AIDED BY A
STRONG LLJ COULD PROVIDE CONTINUED ISOLATED TO SCATTERED
DEVELOPMENT THROUGH EARLY WEDNESDAY MORNING.
SHIFTING GEARS TOWARDS WEDNESDAY...A SIGNIFICANT SEVERE WEATHER
OUTBREAK IS APPEARING TO BE POSSIBLE WITH VARYING MODES OF
CONVECTION. HAIL AND TORNADOES ARE POSSIBLE...AND A SIGNIFICANT
WIND THREAT ACROSS THE SOUTHERN HALF OF THE CWA COULD BE MORE
FAVORED THAN THE RUN OF THE MILL STRONG WINDS/GUSTS.
MULTIPLE ROUNDS OF THUNDERSTORMS WILL ONCE AGAIN BE POSSIBLE
ACROSS THE ENTIRE CWA TOMORROW BEGINNING TOMORROW MORNING.
ANTICIPATED UPSTREAM CONVECTION WILL LIKELY SHIFT EAST BY EARLY
WEDNESDAY MORNING BUT WITH LOCATION AND STRENGTH OF THESE STORMS
STILL NOT FULLY KNOWN. AT THIS TIME...IT APPEARS THAT THIS SHOULD
STAY TO THE NORTH OF THE CWA BUT WITH AREAS ACROSS FAR NORTHERN
ILLINOIS OBSERVING THE GREATER THREAT TO OBSERVE THIS
THUNDERSTORM POTENTIAL TOMORROW MORNING...BUT WITH ONCE AGAIN
CONFIDENCE REMAINING LOW. ITS CONCEIVABLE THAT WE COULD BE
DEALING WITH ANOTHER MCS COMPLEX AND ANOTHER ROUND OF HIGH
WINDS/HAIL. ANY REMAINING CONVECTION IS EXPECTED TO SHIFT EAST OF
THE AREA BY MID/LATE MORNING WITH A PERIOD OF DRY WEATHER
POSSIBLE FROM LATE MORNING THROUGH EARLY AFTERNOON.
CURRENT STRONGER AND MORE DEFINED MID LEVEL TROUGH SHIFTING
NORTHEAST ACROSS THE NORTHERN ROCKIES AT THIS TIME WILL MOVE EAST
THROUGH THE NORTHERN PLAINS TONIGHT INTO WEDNESDAY MORNING...AND
THEN DROP SOUTHEAST TOWARDS THE AREA BY MIDDAY. THIS WILL ALLOW
THE LOW OVER THE CENTRAL PLAINS TO SHIFT EAST REACHING THE
IOWA/MISSOURI LINE BY MID DAY...AND THEN CONTINUE EAST ACROSS
NORTH CENTRAL ILLINOIS IN THE AFTERNOON. THIS STRONG WAVE
BRINGING 50-60KT OF MID LEVEL FLOW WILL HELP THIS LOW STRENGTHEN
AS IT MOVES THROUGH THE REGION TOMORROW AFTERNOON. THIS STRONG
FORCING OWING TO THIS MID LEVEL FEATURE AND STRENGTHENING LOW IN
A MODERATELY TO STRONGLY UNSTABLE ENVIRONMENT WILL ALLOW FOR
RAPID GROWTH IN THUNDERSTORM COVERAGE AND INTENSITY STARTING AS
SOON AS THE 19Z TIME FRAME. MORE THAN EFFICIENT EFFECTIVE BULK
SHEAR AS WELL AS STEEP LAPSE RATES MOVING OVERHEAD WILL SUPPORT
EXPLOSIVE DEVELOPMENT. ALTHOUGH SEVERE WEATHER WILL BE POSSIBLE
ACROSS THE ENTIRE CWA TOMORROW AFTERNOON INTO THE EVENING...THE
MORE WIDESPREAD DEVELOPMENT IS EXPECTED FOR AREAS ALONG AND SOUTH
OF A DIXON TO CHICAGO LINE. ITS IN THIS AREA WHERE
MOISTURE/INSTABILITY WILL BE THE GREATEST...JUST ALONG AND SOUTH
OF THE SURFACE BOUNDARY. THE MID TO LATE AFTERNOON TIME FRAME IS
WHEN I EXPECT DEVELOPMENT TO REALLY GET GOING WITH SHEAR/WIND
PROFILES SUPPORTIVE OF DISCRETE CONVECTION WITH ROTATING UPDRAFTS
POSSIBLE. ITS DURING THIS INITIAL TIME FRAME THAT THE THREAT OF
TORNADOES WILL BE THE GREATEST NEAR THE SURFACE LOW OR ALONG THE
BOUNDARY. IT SHOULD NOT TAKE LONG AFTER INITIATION TOMORROW FOR
ANY DEVELOPMENT TO QUICKLY CONGEAL INTO A LINE WITH THEN STRONG
DAMAGING WINDS TO BE THE GREATER THREAT INTO THE AFTERNOON AND
EVENING. DO NOT WANT TO COMPLETELY RULE OUT THE TORNADO THREAT
THEREAFTER AS QLCS SPIN-UPS WILL DEFINITELY REMAIN A POSSIBILITY
AS THIS LINE OF THUNDERSTORMS SHIFTS SOUTHEAST ACROSS THE AREA.
EXPECT THIS COMPLEX OF THUNDERSTORMS TO CONTINUE EAST/SOUTHEAST
INTO THE EVENING WITH THE SEVERE THREAT DIMINISHING MORE TOWARDS
THE 9PM TIME FRAME. ALTHOUGH SHOWERS AND THUNDERSTORMS WILL BE
POSSIBLE AFTER MIDNIGHT...THE OVERALL SEVERE THREAT SHOULD BE LOW
AT THAT TIME. EXPECT MID LEVEL TROUGH AND ATTENDANT SURFACE LOW
TO CONTINUE EAST INTO THURSDAY MORNING WITH DRIER CONDITIONS
EXPECTED AS PRECIP SHIELD ALSO EXITS.
RODRIGUEZ
LONG TERM...FRIDAY THROUGH TUESDAY
THE EXTENDED WILL START OUT QUIET AND PLEASANT WITH HIGH PRESSURE
OVERHEAD AND ONSHORE BREEZES ON FRIDAY. HOWEVER...WE WILL QUICKLY
TRANSITION TO A MORE ACTIVE PATTERN AS STRONG UPPER RIDGING
CENTERED OVER THE PLAINS SHIFTS EASTWARD. THE CWA WILL RESIDE ON
THE NORTHERN FRINGE OF THE THE RIDGING...PUTTING US IN THE REGION
OF MODERATE WESTERLIES AND THUS DECENT DEEP LAYER SHEAR. THE
POTENTIAL EXISTS FOR RIDGE RUNNERS PRODUCING CLUSTERS OF
SHRA/TSRA STARTING AS EARLY AS LATE FRIDAY NIGHT INTO EARLY
SATURDAY. THE 12Z ECMWF AND 12Z GFS THEN DIVERGE IN THAT THE GFS
KEEPS US PRIMARILY IN A RING OF FIRE TYPE SET-UP UNTIL LATE
MONDAY...WHILE THE ECMWF HAS A MODESTLY DEEP UPPER TROUGH
BREAKING OFF FROM THE NORTHERN BRANCH WITH TROUGH AND ATTENDANT
SURFACE LOW TRACKING THROUGH WESTERN GREAT LAKES REGION SUNDAY
INTO MONDAY. CONSIDERING UNCERTAINTY...DID NOT MAKE MAJOR CHANGES
TO POPS FROM CONSENSUS BLEND...BUT EVEN DIVERGING MODEL SCENARIOS
KEEP PERIODIC CHANCES FOR SHOWERS AND THUNDERSTORMS UNTIL AT
LEAST A BRIEF QUIETER STRETCH ARRIVES BY NEXT TUESDAY AND
WEDNESDAY IN THE FORM OF HIGH PRESSURE.
ALSO DID NOT MAKE BIG CHANGES TO TEMPERATURES...BUT SYNOPTICALLY
SUNDAY AND MONDAY BOTH LOOK TO BE WARM AND FAIRLY HUMID AND SOME
GUIDANCE DOES HINT AT MID/UPPER 80S...WHICH MAKES SENSE WITH H85
TEMPS IN THE MID TEENS. THUS COULD SEE TEMPERATURES BOTH DAYS
BEING WARMER THAN CURRENTLY INDICATED. THE POTENTIAL FOR LAKE
BREEZES LENDS UNCERTAINTY TO LAKEFRONT TEMPERATURES SATURDAY
THROUGH MONDAY...WITH HIGHER CONFIDENCE IN SYNOPTIC ONSHORE FLOW
ON TUESDAY.
RC
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 06Z...
* STRONG TO SEVERE THUNDERSTORM POTENTIAL AND TIMING LATER TODAY
AND INTO THIS EVENING.
* POTENTIAL FOR VERY HEAVY RAIN THIS EVENING...WITH IFR VIS AND
CIGS POSSIBLE FOR A PERIOD.
* SURFACE WINDS INCREASING OUT OF THE NORTH-NORTHEAST LATER THIS EVENING.
KJB
//DISCUSSION...UPDATED 06Z...
THE MAIN FORECAST CONCERN TODAY WILL BE THE CHANCES OF STRONG TO
SEVERE THUNDERSTORMS LATER THIS AFTERNOON AND INTO THE EVENING.
WATER VAPOR IMAGERY EARLY THIS MORNING INDICATES A SIGNIFICANT MID
LEVEL DISTURBANCE CURRENTLY NEAR THE BLACK HILLS OF SOUTH DAKOTA.
THIS FEATURE WILL BE OF SIGNIFICANT INTEREST FOR TODAY AND INTO THIS
EVENING. THE GUIDANCE CONTINUES TO BRING THIS DISTURBANCE
EAST-SOUTHEASTWARD ACROSS THE AREA BY THIS EVENING. ALTHOUGH THE
AREA WILL REMAIN CAPPED TO SURFACE BASED CONVECTIVE ACTIVITY FOR
MUCH OF THE DAY...THE DYNAMICS ASSOCIATED WITH THIS WAVE SHOULD HAVE
NO PROBLEM COOLING THE MID LEVEL TEMPERATURES AND ELIMINATING THE
CAP LATER THIS AFTER AND EVENING. ONCE THIS OCCURS...SIGNIFICANT
THUNDERSTORM DEVELOPMENT APPEARS TO BE IMMINENT. CURRENT THOUGHTS
ARE LATE THIS AFTERNOON AFTER 21 TO 22 UTC AT THE EASTERN TERMINALS
AND A HOUR OR TWO SOONER AT KRFD. THESE STORMS WILL DEVELOP IN AN
ENVIRONMENT FAVORABLE FOR SEVERE STORMS...WITH LARGE HAIL AND STRONG
DAMAGING WINDS THE MAIN THREATS. HOWEVER...VERY HEAVY RAINFALL WILL
ALSO BECOME A BIG ISSUE...ESPECIALLY THIS EVENING. THIS COULD LEAD TO
LOCALIZED FLOODING AND REDUCTIONS IN THE VIS DOWN UNDER 2 MILES. IT
APPEARS THAT THIS ACTIVITY COULD LAST FOR A 3 TO 6 HOUR WINDOW INTO
THIS EVENING BEFORE CONDITIONS BEGIN TO IMPROVE OVERNIGHT.
KJB
//ORD AND MDW CONFIDENCE...UPDATED 06Z...
* MODERATE TO HIGH CONFIDENCE IN CHANCES FOR THUNDERSTORMS LATER
TODAY AND TONIGHT.
* MODERATE CONFIDENCE IN A PERIOD OF VERY HEAVY RAINFALL WITH
LOWER VIS AND CIGS THIS EVENING.
* MODERATE CONFIDENCE IN WIND FORECAST TONIGHT.
KJB
//OUTLOOK FOR ORD/MDW FOR 12Z THURSDAY-12Z TUESDAY...UPDATED 00Z...
THU AND FRI...VFR. WX NIL.
SAT THRU MON...VFR. CHC TSRA WITH LOCAL MVFR/IFR.
TRS
&&
.MARINE...
229 AM CDT
THE MAIN FORECAST CONCERNS ON THE LAKE IS THE THREAT FOR SEVERE
THUNDERSTORMS THIS AFTERNOON AND EVENING...ESPECIALLY ACROSS
SOUTHERN LAKE MICHIGAN...AND ALSO A PERIOD OF STRONG NORTHERLY WINDS
LATE TONIGHT AND ON THURSDAY.
DENSE FOG REMAINS ACROSS THE LAKE...ESPECIALLY ACROSS THE NORTHERN
HALF OF THE LAKE....AND I REALLY DONT SEE ANY IMPROVEMENT IN THESE
CONDITIONS UNTIL EITHER LATE THIS AFTERNOON OR THIS EVENING...WHEN
THE WINDS START TO BECOME NORTHERLY. THEREFORE...I HAVE EXTENDED THE
ADVISORY FOR THE OPEN WATERS THROUGH THIS AFTERNOON.
SEVERE THUNDERSTORMS LOOK TO BE A GOOD BET THIS AFTERNOON AND
EVENING...ESPECIALLY ACROSS SOUTHERN LAKE MICHGAN. THESE STORMS WILL
BE CAPABLE OF PRODUCING VERY LARGE HAIL AND STRONG DAMAGING WINDS
IN EXCESS OF 50 KT. THE THREAT OF SEVERE STORMS IS QUITE HIGH...SO
KEEP UP TO DATE ON THE LATEST WEATHER INFORMATION.
A SURFACE LOW IS EXPECTED TO PASS SOUTH OF THE LAKE TONIGHT. THIS
WILL SET UP SOME STRONG NORTHERLY WINDS UP TO 30 KT LATE TONIGHT AND
ON THURSDAY. THIS WILL LIKELY RESULT IN SMALL CRAFT ADVISORY
CONDITIONS FOR THE ILLINOIS AND INDIANA NEAR SHORE WATERS DURING THIS
TIME. CONDITIONS SHOULD BEGIN TO IMPROVE ON FRIDAY AS THE WINDS
ABATE AS A SURFACE RIDGE OF HIGH PRESSURE BUILDS ACROSS THE
LAKE.
KJB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...DENSE FOG ADVISORY...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-
LMZ565-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-
LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 4 PM
WEDNESDAY.
&&
$$
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
113 AM CDT WED JUN 12 2013
.DISCUSSION...
834 PM CDT
A FEW THOUGHTS REGARDING THE THUNDERSTORM THREAT OVERNIGHT AND THE
MODERATE RISK FOR SEVERE WEATHER WEDNESDAY...
THIS EVENING...A WARM FRONT EXTENDS FROM WESTERN IOWA EAST TOWARDS
IOWA CITY...THEN LOSES ITS DEFINITION SOUTHEAST INTO CENTRAL
ILLINOIS. LOW TO MID 70 DEW POINTS ARE POOLING ALONG THE BOUNDARY
TO OUR WEST...BUT AS A 20Z SOUNDING OUT OF DVN SHOWED...A STRONG
CAP IS IN PLACE WITH 825MB TEMPS AROUND 21C. LATEST RAP GUIDANCE
INDICATES THE THE CAP WILL REMAIN IN PLACE THROUGH THE REMAINDER
OF THE EVENING AND TONIGHT. WITH THAT SAID....THE THREAT FOR
SEVERE WEATHER THROUGH THE REMAINDER OF TODAY HAS GREATLY
DIMINISHED. FOCUS TURNS OUT TO THE WEST TONIGHT WHERE A 50-60KT
LOW LEVEL JET IS EXPECTED TO DEVELOP WITH THE BEST MOISTURE
CONVERGENCE FOCUSED OVER CENTRAL NEBRASKA...AND BY MIDNIGHT
TONIGHT SLIGHTLY FARTHER EAST OVER THE MID MISSOURI VALLEY.
DESPITE THE FOCUS BEING WELL OFF TO OUR WEST...THERE IS SOME
ASCENT ALONG THE WARM FRONT SO CAN NOT RULE OUT SOMETHING TRYING
TO DEVELOP THIS EVENING NORTH OF THE WARM FRONT AND MOVING INTO
NORTHERN ILLINOIS...BUT EXPECT COVERAGE TO BE LOW AWAY FROM THE
BETTER FORCING WITH THE LLJ. WITH THAT IN MIND...LOWERED POPS
ACROSS MUCH OF THE CWA FOR THE OVERNIGHT HOURS AND FEEL THEY MAY
STILL BE ON THE HIGH END. CONVECTIVE ALLOWING MODELS STILL SHOW
AN MCS DEVELOPING AT THE NOSE OF THE LLJ TONIGHT...AND BY
DAYBREAK TOMORROW POSSIBLY MOVING INTO NORTHWESTERN ILLINOIS...
BUT MORE LIKELY STAYING NORTH OF THE STATE LINE. EITHER WAY...LLJ
IS VEERING AND WEAKENING BY THAT TIME SO CONVECTION SHOULD BE IN
A WEAKENING PHASE.
THE STORM PREDICTION CENTER CONTINUES TO CARRY US UNDER A MODERATE
RISK WEDNESDAY AND THIS SEEMS TO BE ON TRACK. APPEARS WE WILL BE
UNDER A PRETTY DYNAMIC ENVIRONMENT TOMORROW AS A COUPLED JET SETS
UP WITH THE BEST UPPER LEVEL DIVERGENCE OVER CENTRAL AND NORTHERN
ILLINOIS. MODERATE HEIGHT FALLS ASSOCIATED WITH THE MID LEVEL WAVE
MOVING INTO THE AREA LATE AFTERNOON/EARLY EVENING TOMORROW WILL
PROVIDE LARGE SCALE ASCENT ACROSS THE AREA TO HELP WEAKEN THE CAP.
THE SURFACE LOW TRACKS EAST ACROSS THE MISSISSIPPI VALLEY JUST
SOUTH OF MLI...THOUGH THERE ARE SOME MODELS SUGGESTING THE LOW
TRACK AND RESULTING SEVERE THREAT MAY TRACK SLIGHTLY FARTHER
NORTH. SOME MODELS ALSO INDICATE THE LOW DEEPENING SLIGHTLY
TOMORROW AFTERNOON WITH 2-4MB PRESSURE FALLS OVERSPREADING AREAS
SOUTH OF I-80. THIS WILL ONLY HELP TO ENHANCE WHAT ALREADY LOOKS
TO BE PRETTY STRONG LOW LEVEL HELICITY TOMORROW. DEEP LAYER SHEAR
TOMORROW IS ALSO FORECAST TO BE QUITE STRONG. ALL SAID THERE IS
CONCERN FOR DISCRETE SUPER CELLS DEVELOPING IN THE AFTERNOON WITH
THE WHOLE GAMUT OF SEVERE WEATHER POSSIBLE...LARGE HAIL...
DAMAGING WINDS AND QUITE POSSIBLY TORNADOES. STORMS SHOULD
EVENTUALLY CONGEAL INTO A LINE WITH THE MAIN THREAT TURNING
BECOMING DAMAGING WINDS...THOUGH QLCS TORNADOES WILL STILL BE A
CONCERN. HOW QUICKLY WE TRANSITION FROM DISCRETE SUPER CELLS TO A
LINEAR MCS IS UNCERTAIN. INTERESTING TO NOTE THAT ONE OF THE TOP
CIPS ANALOGS IS JUNE 05 2010 WHICH DID HAVE DISCRETE SUPER CELLS
WITH TORNADOES LATER INTO THE EVENING.
DEUBELBEISS
//PREV DISCUSSION...
300 PM CDT
MAIN FORECAST CONCERNS/CHALLENGES IN THE NEAR TERM ARE WITH
MULTIPLE ROUNDS OF CONVECTION POSSIBLE ACROSS THE ENTIRE CWA
TONIGHT THROUGH WEDNESDAY NIGHT WITH SEVERE WEATHER NOT OUT OF
THE QUESTION THIS EVENING AND OVERNIGHT...BUT WITH A MORE
SIGNIFICANT SEVERE WEATHER OUTBREAK BECOMING INCREASINGLY MORE
POSSIBLE ACROSS A PORTION OF THE CWA ON WEDNESDAY.
IN THE NEAR TERM...CONTINUE TO MONITOR CONVECTION DEVELOPING JUST
SOUTHWEST/SOUTH OF THE CWA AT THIS TIME AS A MID LEVEL IMPULSE
SLIDES EAST ACROSS THE AREA AND ENCOUNTERS SOME WEAK LOW/MID
LEVEL CONVERGENCE IN AND AROUND SHIFTING SURFACE TROUGH ACROSS
IOWA. THIS AREA OF CONVECTION SHOULD CONTINUE EAST/SOUTHEAST WITH
TIME FOR THE REMAINDER OF THE AFTERNOON MAINLY ONLY AFFECTING
AREAS FROM LA SALLE IN ILLINOIS SOUTHEAST TO RENSSELAER IN
INDIANA...SUPPORTED BY THIS WAVE AND CURRENT WAA IN PLACE.
ALTHOUGH INSTABILITY REMAINS RATHER WEAK ACROSS THESE AREAS AS
WELL AS CIN IN PLACE...LATEST TRENDS SUPPORT A NORTHEASTWARD
EXPANSION OF THE INSTABILITY AXIS AS WELL AS WEAKENING CIN.
DESPITE WEAKLY FORCED...THESE CONDITIONS COINCIDING WITH
SUFFICIENT BULK SHEAR COULD SUPPORT AN ISOLATED HAIL/WIND THREAT
THROUGH LATE AFTERNOON. GOING INTO THE EARLY EVENING...COULD SEE
A DRY PERIOD FOR MOST OF NORTHERN ILLINOIS AND NORTHWEST INDIANA
BUT WITH THE POSSIBILITY FOR AN INCREASE IN COVERAGE OF
THUNDERSTORMS ONCE AGAIN LATER IN THE EVENING. THIS IS A DEFINITE
POSSIBILITY ESPECIALLY AS SEVERAL MID LEVEL FEATURES/SPEED MAXES
ARE ANTICIPATED TO ROUND THE MID LEVEL RIDGE...AS WELL AS A
VEERING LLJ STRENGTHENS THIS EVENING.
CONTINUE TO MONITOR THESE MID LEVEL FEATURES TRACKING EAST ACROSS
THE CENTRAL AND NORTHERN PLAINS ON LATEST VISIBLE
SATELLITE...TRYING TO GRAB A HANDLE ON THIS POSSIBILITY OF
INCREASED CHANCES FOR CONVECTION LATER THIS EVENING. THIS IS DUE
TO MOST GUIDANCE VARYING TO SOME DEGREE ON PLACEMENT AS WELL AS
TIMING THIS EVENING...WITH CONFIDENCE NOT THE GREATEST FOR
CONVECTIVE EVOLUTION THIS EVENING. ALTHOUGH LATEST THOUGHTS FOR
THIS EVENING ONCE AGAIN DO INCLUDE THE POSSIBILITY FOR AN
INCREASED CHANCE FOR THUNDERSTORMS AS WELL AS THE POSSIBILITY FOR
SEVERE WEATHER...DAMAGING WINDS AND HAIL ONCE AGAIN THE MAIN
THREATS. MID LEVEL FEATURE MOVING OUT OF THE CENTRAL PLAINS
SHOULD ENCOUNTER STRONG LOW/MID LEVEL CONVERGENCE IN IOWA...AND
SHOULD THEN SEE AN UP-GROWTH IN CONVECTION ACROSS EASTERN IOWA
JUST AFTER THE 7PM TIME FRAME. LATEST GUIDANCE IS SHOWING THAT
THE CURRENT NORTHEASTWARD EXPANSION OF THIS INSTABILITY AXIS WILL
CONTINUE THIS EVENING AND ORIENT ITSELF ACROSS NORTH CENTRAL/EAST
CENTRAL ILLINOIS. THIS INCREASED INSTABILITY AS WELL AS
SUFFICIENT 0-3/0-6KM BULK SHEAR THIS EVENING LENDS ITSELF TO
SUPPORT A POSSIBLE WIND THREAT ACROSS NORTH CENTRAL...NORTHEAST
ILLINOIS...AS WELL AS NORTHWEST INDIANA AROUND THE 9PM TIME FRAME.
ANY DEVELOPMENT IS THEN EXPECTED TO SHIFT SOUTHEAST OF THE CWA
AFTER THE MIDNIGHT TIME FRAME...BUT THUNDERSTORMS STILL NOT BE
OUT OF THE QUESTION AFTER MIDNIGHT. PERSISTENT WAA AIDED BY A
STRONG LLJ COULD PROVIDE CONTINUED ISOLATED TO SCATTERED
DEVELOPMENT THROUGH EARLY WEDNESDAY MORNING.
SHIFTING GEARS TOWARDS WEDNESDAY...A SIGNIFICANT SEVERE WEATHER
OUTBREAK IS APPEARING TO BE POSSIBLE WITH VARYING MODES OF
CONVECTION. HAIL AND TORNADOES ARE POSSIBLE...AND A SIGNIFICANT
WIND THREAT ACROSS THE SOUTHERN HALF OF THE CWA COULD BE MORE
FAVORED THAN THE RUN OF THE MILL STRONG WINDS/GUSTS.
MULTIPLE ROUNDS OF THUNDERSTORMS WILL ONCE AGAIN BE POSSIBLE
ACROSS THE ENTIRE CWA TOMORROW BEGINNING TOMORROW MORNING.
ANTICIPATED UPSTREAM CONVECTION WILL LIKELY SHIFT EAST BY EARLY
WEDNESDAY MORNING BUT WITH LOCATION AND STRENGTH OF THESE STORMS
STILL NOT FULLY KNOWN. AT THIS TIME...IT APPEARS THAT THIS SHOULD
STAY TO THE NORTH OF THE CWA BUT WITH AREAS ACROSS FAR NORTHERN
ILLINOIS OBSERVING THE GREATER THREAT TO OBSERVE THIS
THUNDERSTORM POTENTIAL TOMORROW MORNING...BUT WITH ONCE AGAIN
CONFIDENCE REMAINING LOW. ITS CONCEIVABLE THAT WE COULD BE
DEALING WITH ANOTHER MCS COMPLEX AND ANOTHER ROUND OF HIGH
WINDS/HAIL. ANY REMAINING CONVECTION IS EXPECTED TO SHIFT EAST OF
THE AREA BY MID/LATE MORNING WITH A PERIOD OF DRY WEATHER
POSSIBLE FROM LATE MORNING THROUGH EARLY AFTERNOON.
CURRENT STRONGER AND MORE DEFINED MID LEVEL TROUGH SHIFTING
NORTHEAST ACROSS THE NORTHERN ROCKIES AT THIS TIME WILL MOVE EAST
THROUGH THE NORTHERN PLAINS TONIGHT INTO WEDNESDAY MORNING...AND
THEN DROP SOUTHEAST TOWARDS THE AREA BY MIDDAY. THIS WILL ALLOW
THE LOW OVER THE CENTRAL PLAINS TO SHIFT EAST REACHING THE
IOWA/MISSOURI LINE BY MID DAY...AND THEN CONTINUE EAST ACROSS
NORTH CENTRAL ILLINOIS IN THE AFTERNOON. THIS STRONG WAVE
BRINGING 50-60KT OF MID LEVEL FLOW WILL HELP THIS LOW STRENGTHEN
AS IT MOVES THROUGH THE REGION TOMORROW AFTERNOON. THIS STRONG
FORCING OWING TO THIS MID LEVEL FEATURE AND STRENGTHENING LOW IN
A MODERATELY TO STRONGLY UNSTABLE ENVIRONMENT WILL ALLOW FOR
RAPID GROWTH IN THUNDERSTORM COVERAGE AND INTENSITY STARTING AS
SOON AS THE 19Z TIME FRAME. MORE THAN EFFICIENT EFFECTIVE BULK
SHEAR AS WELL AS STEEP LAPSE RATES MOVING OVERHEAD WILL SUPPORT
EXPLOSIVE DEVELOPMENT. ALTHOUGH SEVERE WEATHER WILL BE POSSIBLE
ACROSS THE ENTIRE CWA TOMORROW AFTERNOON INTO THE EVENING...THE
MORE WIDESPREAD DEVELOPMENT IS EXPECTED FOR AREAS ALONG AND SOUTH
OF A DIXON TO CHICAGO LINE. ITS IN THIS AREA WHERE
MOISTURE/INSTABILITY WILL BE THE GREATEST...JUST ALONG AND SOUTH
OF THE SURFACE BOUNDARY. THE MID TO LATE AFTERNOON TIME FRAME IS
WHEN I EXPECT DEVELOPMENT TO REALLY GET GOING WITH SHEAR/WIND
PROFILES SUPPORTIVE OF DISCRETE CONVECTION WITH ROTATING UPDRAFTS
POSSIBLE. ITS DURING THIS INITIAL TIME FRAME THAT THE THREAT OF
TORNADOES WILL BE THE GREATEST NEAR THE SURFACE LOW OR ALONG THE
BOUNDARY. IT SHOULD NOT TAKE LONG AFTER INITIATION TOMORROW FOR
ANY DEVELOPMENT TO QUICKLY CONGEAL INTO A LINE WITH THEN STRONG
DAMAGING WINDS TO BE THE GREATER THREAT INTO THE AFTERNOON AND
EVENING. DO NOT WANT TO COMPLETELY RULE OUT THE TORNADO THREAT
THEREAFTER AS QLCS SPIN-UPS WILL DEFINITELY REMAIN A POSSIBILITY
AS THIS LINE OF THUNDERSTORMS SHIFTS SOUTHEAST ACROSS THE AREA.
EXPECT THIS COMPLEX OF THUNDERSTORMS TO CONTINUE EAST/SOUTHEAST
INTO THE EVENING WITH THE SEVERE THREAT DIMINISHING MORE TOWARDS
THE 9PM TIME FRAME. ALTHOUGH SHOWERS AND THUNDERSTORMS WILL BE
POSSIBLE AFTER MIDNIGHT...THE OVERALL SEVERE THREAT SHOULD BE LOW
AT THAT TIME. EXPECT MID LEVEL TROUGH AND ATTENDANT SURFACE LOW
TO CONTINUE EAST INTO THURSDAY MORNING WITH DRIER CONDITIONS
EXPECTED AS PRECIP SHIELD ALSO EXITS.
RODRIGUEZ
LONG TERM...FRIDAY THROUGH TUESDAY
THE EXTENDED WILL START OUT QUIET AND PLEASANT WITH HIGH PRESSURE
OVERHEAD AND ONSHORE BREEZES ON FRIDAY. HOWEVER...WE WILL QUICKLY
TRANSITION TO A MORE ACTIVE PATTERN AS STRONG UPPER RIDGING
CENTERED OVER THE PLAINS SHIFTS EASTWARD. THE CWA WILL RESIDE ON
THE NORTHERN FRINGE OF THE THE RIDGING...PUTTING US IN THE REGION
OF MODERATE WESTERLIES AND THUS DECENT DEEP LAYER SHEAR. THE
POTENTIAL EXISTS FOR RIDGE RUNNERS PRODUCING CLUSTERS OF
SHRA/TSRA STARTING AS EARLY AS LATE FRIDAY NIGHT INTO EARLY
SATURDAY. THE 12Z ECMWF AND 12Z GFS THEN DIVERGE IN THAT THE GFS
KEEPS US PRIMARILY IN A RING OF FIRE TYPE SET-UP UNTIL LATE
MONDAY...WHILE THE ECMWF HAS A MODESTLY DEEP UPPER TROUGH
BREAKING OFF FROM THE NORTHERN BRANCH WITH TROUGH AND ATTENDANT
SURFACE LOW TRACKING THROUGH WESTERN GREAT LAKES REGION SUNDAY
INTO MONDAY. CONSIDERING UNCERTAINTY...DID NOT MAKE MAJOR CHANGES
TO POPS FROM CONSENSUS BLEND...BUT EVEN DIVERGING MODEL SCENARIOS
KEEP PERIODIC CHANCES FOR SHOWERS AND THUNDERSTORMS UNTIL AT
LEAST A BRIEF QUIETER STRETCH ARRIVES BY NEXT TUESDAY AND
WEDNESDAY IN THE FORM OF HIGH PRESSURE.
ALSO DID NOT MAKE BIG CHANGES TO TEMPERATURES...BUT SYNOPTICALLY
SUNDAY AND MONDAY BOTH LOOK TO BE WARM AND FAIRLY HUMID AND SOME
GUIDANCE DOES HINT AT MID/UPPER 80S...WHICH MAKES SENSE WITH H85
TEMPS IN THE MID TEENS. THUS COULD SEE TEMPERATURES BOTH DAYS
BEING WARMER THAN CURRENTLY INDICATED. THE POTENTIAL FOR LAKE
BREEZES LENDS UNCERTAINTY TO LAKEFRONT TEMPERATURES SATURDAY
THROUGH MONDAY...WITH HIGHER CONFIDENCE IN SYNOPTIC ONSHORE FLOW
ON TUESDAY.
RC
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 06Z...
* STRONG TO SEVERE THUNDERSTORM POTENTIAL AND TIMING LATER TODAY
AND INTO THIS EVENING.
* POTENTIAL FOR VERY HEAVY RAIN THIS EVENING...WITH IFR VIS AND
CIGS POSSIBLE FOR A PERIOD.
* SURFACE WINDS INCREASING OUT OF THE NORTH-NORTHEAST LATER THIS EVENING.
KJB
//DISCUSSION...UPDATED 06Z...
THE MAIN FORECAST CONCERN TODAY WILL BE THE CHANCES OF STRONG TO
SEVERE THUNDERSTORMS LATER THIS AFTERNOON AND INTO THE EVENING.
WATER VAPOR IMAGERY EARLY THIS MORNING INDICATES A SIGNIFICANT MID
LEVEL DISTURBANCE CURRENTLY NEAR THE BLACK HILLS OF SOUTH DAKOTA.
THIS FEATURE WILL BE OF SIGNIFICANT INTEREST FOR TODAY AND INTO THIS
EVENING. THE GUIDANCE CONTINUES TO BRING THIS DISTURBANCE
EAST-SOUTHEASTWARD ACROSS THE AREA BY THIS EVENING. ALTHOUGH THE
AREA WILL REMAIN CAPPED TO SURFACE BASED CONVECTIVE ACTIVITY FOR
MUCH OF THE DAY...THE DYNAMICS ASSOCIATED WITH THIS WAVE SHOULD HAVE
NO PROBLEM COOLING THE MID LEVEL TEMPERATURES AND ELIMINATING THE
CAP LATER THIS AFTER AND EVENING. ONCE THIS OCCURS...SIGNIFICANT
THUNDERSTORM DEVELOPMENT APPEARS TO BE IMMINENT. CURRENT THOUGHTS
ARE LATE THIS AFTERNOON AFTER 21 TO 22 UTC AT THE EASTERN TERMINALS
AND A HOUR OR TWO SOONER AT KRFD. THESE STORMS WILL DEVELOP IN AN
ENVIRONMENT FAVORABLE FOR SEVERE STORMS...WITH LARGE HAIL AND STRONG
DAMAGING WINDS THE MAIN THREATS. HOWEVER...VERY HEAVY RAINFALL WILL
ALSO BECOME A BIG ISSUE...ESPECIALLY THIS EVENING. THIS COULD LEAD TO
LOCALIZED FLOODING AND REDUCTIONS IN THE VIS DOWN UNDER 2 MILES. IT
APPEARS THAT THIS ACTIVITY COULD LAST FOR A 3 TO 6 HOUR WINDOW INTO
THIS EVENING BEFORE CONDITIONS BEGIN TO IMPROVE OVERNIGHT.
KJB
//ORD AND MDW CONFIDENCE...UPDATED 06Z...
* MODERATE TO HIGH CONFIDENCE IN CHANCES FOR THUNDERSTORMS LATER
TODAY AND TONIGHT.
* MODERATE CONFIDENCE IN A PERIOD OF VERY HEAVY RAINFALL WITH
LOWER VIS AND CIGS THIS EVENING.
* MODERATE CONFIDENCE IN WIND FORECAST TONIGHT.
KJB
//OUTLOOK FOR ORD/MDW FOR 12Z THURSDAY-12Z TUESDAY...UPDATED 00Z...
THU AND FRI...VFR. WX NIL.
SAT THRU MON...VFR. CHC TSRA WITH LOCAL MVFR/IFR.
TRS
&&
.MARINE...
243 PM...MAIN FORECAST CONCERN/CHALLENGE THROUGH WEDNESDAY MORNING
REMAINS DENSE FOG. SOUTHERLY WINDS HAVE PUSHED THE FOG NORTH...
ROUGHLY FROM HOLLAND TO MILWAUKEE. LITTLE IMPROVEMENT SEEN NORTH
OF THERE. SOUTHERLY WINDS DIMINISH THIS EVENING AND BEGIN TURNING
BACK EAST AND THEN NORTHEAST OVERNIGHT INTO WEDNESDAY MORNING...
SO THERE IS SOME POTENTIAL FOR THE FOG TO DRIFT BACK SOUTH. WHILE
CONFIDENCE REMAINS SOMEWHAT LOW...HAVE OPTED TO CONTINUE THE DENSE
FOG ADVISORY FOR ALL OF THE OPEN WATERS THROUGH WEDNESDAY MORNING.
LOW PRESSURE OVER COLORADO WILL MOVE EAST AND DEEPEN TONIGHT...
PASSING ACROSS NORTH CENTRAL ILLINOIS WEDNESDAY AFTERNOON AND THEN
ACROSS NORTHERN INDIANA WEDNESDAY EVENING. THE GRADIENT WILL
TIGHTEN AHEAD OF THIS LOW WITH NORTHEASTERLY WINDS INCREASING
WEDNESDAY AFTERNOON...THEN TURNING NORTHERLY AND INCREASING FURTHER
WEDNESDAY EVENING. A PERIOD OF 15-25 KTS STILL LOOKS ON TRACK AND
OVER THE SOUTHERN THIRD OR QUARTER OF THE LAKE...THERE COULD BE A
PERIOD OF 20-25 KTS WITH GUSTS PERHAPS AS HIGH AS 30 KTS. THE
GRADIENT WILL BE SLOW TO RELAX THURSDAY INTO THURSDAY NIGHT AS HIGH
PRESSURE BUILDS ACROSS THE UPPER MIDWEST AND NORTHERN LAKES...
EVENTUALLY SPREADING ACROSS THE LAKES REGION FRIDAY. CMS
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...DENSE FOG ADVISORY...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-
LMZ565-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-
LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 9 AM
WEDNESDAY.
&&
$$
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AREA FORECAST DISCUSSION
NWS GOODLAND KS
1100 PM MDT TUE JUN 11 2013
.UPDATE...
ISSUED AT 901 PM MDT TUE JUN 11 2013
RED FLAG WARNING ALLOWED TO EXPIRE ON TIME.
AT 03Z COLD FRONT EXTENDED FROM NEAR TRENTON NEBRASKA SOUTHWEST
THROUGH SAINT FRANCIS KS TO NEAR BURLINGTON COLORADO. BEHIND THE
FRONT NORTH TO NORTHEAST WINDS GUSTING TO 25 MPH WITH DEWPOINTS
RAPIDLY INCREASING INTO THE 40S TO MID 60S. 01Z HRRR AND TO A
LESSER EXTENT RUC HAVE A PRETTY GOOD HANDLE ON THINGS COMPARED TO
CURRENT OBSERVATIONS SO HAVE FOLLOWED PRETTY CLOSELY. FRONT SHOULD
CLEAR THE EASTERN FORECAST AREA BY 09Z OR SO.
UPDATE ISSUED AT 404 PM MDT TUE JUN 11 2013
ADDED GRAHAM COUNTY TO RED FLAG WARNING BASED ON CURRENT AND
SEVERAL LAST HOURS OF WIND/HUMIDITY OBSERVATIONS.
&&
.SHORT TERM...(THIS AFTERNOON THROUGH WEDNESDAY)
ISSUED AT 108 PM MDT TUE JUN 11 2013
LATEST VISIBLE SATELLITE INDICATES CUMULUS CLOUDS FORMING OVER FAR
NORTHEAST COLORADO EARLY THIS AFTERNOON AHEAD OF AN UPPER LEVEL
SHORT WAVE TROUGH. AT THE SURFACE A LOW PRESSURE WAS LOCATED OVER
FAR NORTHWEST KANSAS WITH A WARM FRONT STRETCHING EAST OF IT OVER
SOUTHERN NEBRASKA. A DRY LINE NOT TOO FAR SOUTH OF THE FRONT
ARCHING OVER FAR NORTHWEST KANSAS THEN EXTENDING SOUTHEAST TO NEAR
HILLY CITY AND HAYS. AS OF EARLY THIS AFTERNOON WINDS ARE STILL
LIGHT OVER MOST OF THE AREA WHERE THE CAP HAS YET TO ERODE.
FOR THE REST OF THE AFTERNOON WINDS SHOULD BEGIN TO INCREASE BY MID
AFTERNOON AS THE CAP ERODES AND ALLOWS THE STRONGER WINDS TO MIX TO
THE GROUND. WITH THE DRY LINE WELL INTO THE AREA BY LATE AFTERNOON
RELATIVE HUMIDITIES BEHIND IT WILL FALL TO AROUND 10 PERCENT. THE
COMBINATION OF GUSTY WINDS AND LOW RELATIVE HUMIDITIES WILL CREATE
HAZARDOUS FIRE WEATHER CONDITIONS FOR MUCH OF THE AREA. SEE THE
FIRE WEATHER SECTION FOR MORE INFORMATION. DURING THE LATTER HALF
OF THE AFTERNOON LIFT INCREASES OVER THE AREA AHEAD OF A MID LEVEL
SHORT WAVE TROUGH. THE LIFT AND MOISTURE WILL BE CO-LOCATED OVER
THE CENTRAL AND EASTERN PART OF THE AREA...WITH LESS MOISTURE TO THE
WEST AND LESS LIFT TO THE EAST. WITH A DEEP DRY LAYER UP TO 500MB
AND MOST UNSTABLE MIXED 1KM CAPE RANGING FROM 500-1500 J/KG...AM
EXPECTING STORM COVERAGE TO BE VERY SPARSE AT BEST THIS AFTERNOON.
THE MAIN THREAT WITH THESE STORMS WILL BE STRONG TO SEVERE WIND
GUSTS THROUGH EARLY EVENING.
THIS EVENING THE LIFT WILL MOVE EAST AHEAD OF THE MID LEVEL TROUGH.
BY MID EVENING THE ENVIRONMENT BECOMES STABLE CAUSING ANY STORMS
TO COME TO AN END. OVERNIGHT A COOLER AIR MASS WILL
MOVE INTO THE AREA.
WEDNESDAY CAPPING AND AN UPPER LEVEL RIDGE WILL KEEP THE AREA DRY.
HIGHS WILL BE SOMEWHAT COOLER THAN YESTERDAY BUT STILL ABOVE NORMAL
AND WINDS WILL BE LIGHT TO BREEZY.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 226 PM MDT TUE JUN 11 2013
WEDNESDAY NIGHT AND THURSDAY THE UPPER RIDGE REMAINS IN PLACE OVER
THE HIGH PLAINS WITH WARM TEMPERATURES EXPECTED TO CONTINUE.
RETURN FLOW AROUND THE SURFACE HIGH PRESSURE AREA OVER THE
NORTHERN PLAINS WILL BRING ADDITIONAL NEAR SURFACE MOISTURE INTO
THE AREA. IN ADDITION TO A DEEPENING LEE SURFACE TROUGH THAT
PROVIDES FOCUS FOR THUNDERSTORMS DEVELOPMENT...A SHORT WAVE TROUGH
AHEAD OF THE MAIN UPPER TROUGH OVER THE PACIFIC NORTHWEST RIDES
UP THROUGH THE BACK SIDE OF THE UPPER RIDGE THURSDAY NIGHT FOR A
CHANCE OF THUNDERSTORMS ACROSS THE FORECAST AREA THURSDAY
AFTERNOON THROUGH THURSDAY NIGHT.
THE SURFACE LOW PRESSURE CENTER AND COLD FRONT MOVES THROUGH THE
FORECAST AREA LATE FRIDAY AS THE RIDGE AXIS MOVES EAST OF THE
REGION AND THE MAIN UPPER TROUGH MOVES ACROSS THE U.S./CANADIAN
BORDER AREA...FLATTENING THE RIDGE ON SATURDAY AND PRODUCING A
DIRTY ZONAL FLOW ACROSS THE CENTRAL HIGH PLAINS REGION THROUGH
SUNDAY. THIS WILL BRING SLIGHTLY COOLER TEMPERATURES AND ANOTHER
ROUND OF THUNDERSTORMS FRIDAY AND SATURDAY AFTERNOON AND EVENING.
ANOTHER RIDGE BEGINS TO AMPLIFY OVER THE ROCKIES BY LATE
SUNDAY...MOVING INTO POSITION OVER THE HIGH PLAINS REGION BY THE
FIRST PART OF NEXT WEEK WITH WARMER TEMPERATURES AND ONLY ISOLATED
THUNDERSTORMS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1100 PM MDT TUE JUN 11 2013
KGLD...VFR EXPECTED THROUGH THE PERIOD. COLD FRONT HAS MOVED
THROUGH THE TERMINAL. FOR THE NEXT 24 HOURS NORTH TO NORTHWEST
WINDS AROUND 10KTS WILL BECOME A LITTLE GUSTY BY 15Z AND CONTINUE
THROUGH 20Z BEFORE DECREASING AND VEERING TO THE NORTHEAST THEN
EAST AT 10KTS OR LESS THROUGH THE REST OF THE TAF PERIOD.
KMCK...MESOSCALE SITUATION SIMILAR TO KGLD. COLD FRONT EXPECTED TO
PUSH THROUGH THE TERMINAL IN THE 06Z-07Z TIME FRAME WITH NORTHWEST
WINDS GUSTING AROUND 25KTS. BY 09Z WEST/NORTHWEST WINDS
EXPECTED...INCREASING FROM THE NORTHWEST AT 15G25KTS BY 15Z AND
CONTINUING THROUGH 21Z WHEN THEY VEER TO THE NORTHEAST THEN EAST
AT 10KTS OR LESS. STILL LOOKING AT THE POSSIBILITY OF MVFR/IFR
CIGS IN THE 10Z-14Z TIMEFRAME...FOR NOW HAVE A TEMPO
GROUP...OTHERWISE VFR EXPECTED.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...99
SHORT TERM...JTL
LONG TERM...LOCKHART
AVIATION...99
AREA FORECAST DISCUSSION
NWS CARIBOU ME
1252 AM EDT WED JUN 12 2013
.SYNOPSIS...
LOW PRESSURE WILL TRACK INTO THE GULF OF MAINE TONIGHT THEN EXIT
ACROSS SOUTHERN NOVA SCOTIA LATE WEDNESDAY. HIGH PRESSURE WILL
BUILD OVER THE AREA THURSDAY.
&&
.NEAR TERM /THROUGH WEDNESDAY/...
MIDNIGHT UPDATE...INCREASED RAIN COVERAGE OVER THE NORTH AND
DECREASED COVERAGE DOWNEAST. RAISED TEMPS A BIT TOO WITH HUMID AIR
AND CLOUD COVER KEEPING AIR FROM COOLING.
PREV DISC: MAIN CHALLENGES WILL BE QPF AND PLACEMENT.
THE FLOOD WATCH FOR THE CENTRAL AND DOWNEAST AREAS HAS BEEN
DROPPED AS MAJOR FLOODING NOT EXPECTED/THIS EVENT. SO FAR, STORM
TOTALS HAVE BEEN 0.25 TO AROUND 0.50 FROM THE CENTRAL HIGHLANDS
DOWN TO THE COAST AND THIS HAS BEEN MAINLY INTERIOR DOWNEAST AND
COAST. FURTHER NORTH, AMOUNTS OF 005 TO 0.10 MAINLY FROM HOULTON TO
MILLINOCKET W/SOME ISOLATED AREAS OF UP TO 0.25 SUCH AS KNOWLES
CORNER DUE TO SOME CONVERGENCE. 18Z RADAR HAD LARGE AREA OF
MAINLY LIGHT RAIN ACROSS NORTH-CENTRAL AREAS ALIGNING W/A THETA E
AXIS STRETCHING FROM NEW BRUNSWICK BACK ACROSS WSW MAINE. ANOTHER
AREA OF RAIN DOWN ACROSS DOWNEAST AND EASTERN AREAS LIFTING NORTH.
THIS AREA WILL MOVE INTO A MORE FAVORABLE ENVIRONMENT AND CONVERGE
WITH THE AREA ACROSS THE NORTH CENTRAL REGION. FURTHER NORTH
ACROSS THE CROWN OF MAINE, SUBSIDENCE FROM THE UPPER RIDGE IS
HOLDING PRECIP SHIELD AT BAY.
LOW PRES AT THE SFC WILL MOVE INTO THE GULF OF MAINE AND WILL STRENGTHEN
TONIGHT INTO WEDNESDAY. THE LATEST RUC AND HRRR HANDLE THIS WELL
AND LEANED CLOSE TO THIS BLEND INTO TONIGHT. THEREFORE, RAIN IS
EXPECTED TO FILL IN TONIGHT AS THE LOW MOVES EAST. LLVL CONVERGENCE
AND FORCING AT THE MID LEVELS WILL AID IN ENHANCING AND EXPANDING
THE RAINFALL. ATTM, PUSHED POPS UP TO NEAR 100% ACROSS THE WESTERN
AROOSTOOK AND NW PISCATAQUIS REGION TO MATCH UP W/THE RADAR TRENDS
AND RUC PLACEMENT. AS LOW PRES LIFTS ACROSS THE GULF OF MAINE
TONIGHT INTO WEDNESDAY, THE RAIN SHIELD WILL PIVOT SOUTHWARD AS
NORTHERN AND WESTERN AREAS GET UNDER NVA AND LESS FORCING. THE BEST
CONVERGENCE AND FORCING WILL BE ACROSS THE INTERIOR DOWNEAST AND
EASTERN AREAS ON WEDNESDAY AS DEPICTED WELL BY THE ECMWF AND NOW
THE GFS. AN AREA OF ENHANCED RAINFALL IS EXPECTED IN THESE AREAS
AS THE 700MBS LOW MOVES ACROSS THE REGION W/FRONTOGENETICAL
FORCING SETTING UP. DECIDED TO LEAN W/THE NERFC QPF TO ACCOUNT FOR
THIS THINKING W/AND ADDITIONAL 0.75 INCHES OF RAINFALL FROM
12-00Z. RAINFALL WILL BEGIN TO WIND DOWN LATER IN THE AFTERNOON AS
THE LOW GETS CAPTURED AND PULLS FURTHER EAST ACROSS THE SOUTHERN
TIP OF NOVA SCOTIA. NORTHERN AND WESTERN AREAS WILL DRY OUT W/RAIN
ENDING.
TEMPERATURES TONIGHT WILL BE HELD DUE TO THE CLOUDS AND RAIN
MAINLY RUNNING IN THE 50S CWA WIDE. COOLER FOR WEDNESDAY USING A
BLEND OF THE NAM12/GMOS AND ECMWFMOS WHICH SHOWED LOW TO MID 60S
NORTH AND WEST AND UPPER 50S TO AROUND 60S CENTRAL AND DOWNEAST
AREAS. A NE WIND PICKING UP AT 10 TO 20 MPH ON WEDNESDAY ON
BACKSIDE OF THE LOW WILL AID IN THE COOLER TEMPERATURES.&&
.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY/...
LOW PRESSURE NEAR SOUTHERN NOVA SCOTIA CONTINUES TO MOVE OFF TO
THE EAST AT THE BEGINNING OF THIS PERIOD WHILE WEAK HIGH PRESSURE
BUILDS IN OVER THE STATE EARLY THURSDAY. LOW PRESSURE IS THEN
EXPECTED TO PASS TO THE SOUTH FRIDAY. WILL BLEND THE
NAM...GFS...SREF AND ECMWF FOR POPS AND QPF WITH HIGHEST POPS
EXPECTED SOUTH FRIDAY. FOR WIND GRIDS WILL BLEND THE NAM12 AND
GMOS. WILL USE 150 PERCENT OF SUSTAINED WIND SPEED FOR GUSTS.
TEMPERATURE INITIALIZED WITH THE GMOS. WILL ADD 3 DEGREES FOR
MINIMUM TEMPERATURE AND 2 DEGREES TO MAXIMUM TEMPERATURE TO
COMPENSATE FOR LOW GMOS BIAS LAST SEVERAL DAYS.
&&
.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
LOW PRESSURE WILL BE PULLING AWAY FROM THE FORECAST AREA FRIDAY
NIGHT, FOLLOWED BY A RIDGE OF HIGH PRESSURE. THE HIGH WILL MOVE
ACROSS THE EASTERN CONUS SATURDAY AND SUNDAY, LEADING TO A MOSTLY
DRY WEEKEND. HOWEVER, PRECIPITATION RETURNS EARLY NEXT WEEK AS A
SERIES OF DISTURBANCES MOVES THROUGH THE NEARLY ZONAL FLOW ALOFT.
TEMPERATURES WILL BE SEASONABLE THROUGH THE PERIOD.
&&
.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
NEAR TERM: VFR ACROSS THE FAR NORTHERN TERMINALS THIS EVENING
DROPPING TO MVFR TONIGHT INTO EARLY WEDNESDAY. IMPROVEMENT TO VFR
IS EXPECTED BY WEDNESDAY NIGHT INTO THURSDAY. FROM KHUL DOWN INTO
KBGR AND KBHB, MVFR TO IFR TONIGHT INTO WEDNESDAY AFTERNOON AND
THEN CONDITIONS LOOK LIKE THEY WILL IMPROVE TO VFR WEDNESDAY NIGHT
INTO THURSDAY. THERE IS POTENTIAL FOR SOME MVFR AND POSSIBLY IFR
BY FRIDAY W/A ESE FLOW SETTING UP. VFR EXPECTED FOR THE WEEKEND.
SHORT TERM: VFR CONDITIONS EXPECTED THURSDAY AND FRIDAY. ONLY
EXCEPTION IS KBGR AND KBHB WHERE IFR/MVFR CONDITIONS POSSIBLE
THURSDAY NIGHT INTO FRIDAY.
&&
.MARINE...
NEAR TERM: UPDATE 1900L: ADDED AREAS OF FOG INTO WED AM...
PREV DISC: SCA FOR HAZARDOUS SEAS IN PLACE. A SOUTHERLY SWELL IS
OUT THERE ATTM W/WAVES OF 3 FT AND A 8-9 SECOND PERIOD. A BRIEF
WINDOW(3-6HR) OF WINDS APCHG 25 KTS IS EXPECTED ON WEDNESDAY ON
THE BACKSIDE OF THE LOW. WINDS WILL COME DOWN AS THE LOW PULLS
TOWARD NOVA SCOTIA. WAVES HEIGHTS CLIMBING ATTM TO 5-6 FT PER THE
LATEST OBS. DECIDED TO BRING WAVES UP A FOOT TO HIT 7-8 FT W/THE
LONG SOUTHERLY FETCH. THE LATEST SWAN GUIDANCE HAD THIS HANDLED WELL.
SHORT TERM: FOR WIND WILL USE A 50/50 BLEND OF THE NAM12 AND
GFS40. HAVE LOWERED SUSTAINED WIND SPEED BY 20 PERCENT TO
COMPENSATE FOR MARINE LAYER. FOR GUST SPEED WILL USE 125 PERCENT
OF SUSTAINED WINDS. FOR WAVES: NORTHEAST WIND WAVES PRIMARY WAVE
GROUP THURSDAY AND FRIDAY WITH SECONDARY SOUTHERLY SWELL OUT OF
SOUTH (2 FEET/9 SECONDS). WILL USE NAM/SWAN TO INITIALIZE WAVE
GRIDS AND WILL REDUCE WAVE HEIGHT 1 FOOT TO COMPENSATE FOR HIGH
BIAS EXPECTED FROM NAM WINDS.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
MARINE...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 2 AM EDT
THURSDAY FOR ANZ050>052.
&&
$$
NEAR TERM...BLOOMER
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
330 AM EDT WED JUN 12 2013
LATEST UPDATE...
SYNOPSIS/SHORT TERM/LONG TERM/HYDRO/MARINE
.SYNOPSIS...
ISSUED AT 330 AM EDT WED JUN 12 2013
AS LOW PRESSURE MOVES EAST FROM THE PLAINS TOWARD NORTHERN INDIANA
TODAY SHOWERS AND THUNDERSTORMS WILL DEVELOP. SOME OF THE STORMS
COULD BE STRONG TO SEVERE ESPECIALLY SOUTH OF I-94 WITH HIGH WINDS
THE MAIN THREAT. HEAVY RAIN WILL BE POSSIBLE THIS AFTERNOON AND
EVENING TOO SOUTH OF I-96. QUIETER WEATHER WILL RETURN THURSDAY
THROUGH SATURDAY AS THE LOW MOVES EAST AND NORTH WINDS ADVECT DRIER
AIR INTO LOWER MICHIGAN.
&&
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 330 AM EDT WED JUN 12 2013
FORECAST CONCERNS DEAL WITH CONVECTIVE TRENDS THIS MORNING THROUGH
THIS EVENING.
LATEST REGIONAL RADAR SHOWS THAT STORMS HAVE FIRED AS EXPECTED IN
NORTHEAST NEBRASKA ON THE NOSE OF A STRONG LLJ. THESE STORMS HAVE
MOVED INTO NW IOWA. A BIT FARTHER NORTH OVER SOUTH DAKOTA ANOTHER
AREA OF STORMS IS MOVE EWD. THESE ARE ASSOCIATED WITH A SHORT WAVE
MOVING ACROSS THE NRN PLAINS. SHORT RANGE MODELS MOVE THIS SHORT
WAVE SEWD TOWARD CHICAGO BY THIS AFTERNOON AT THE SAME TIME THE SFC
LOW IN SRN NEBRASKA IS MOVING ENEWD. HRRR SHOWS BOTH CLUSTERS OF
STORMS WEAKENING AS THEY MOVE EAST WITH THE IOWA CONVECTION MOVING
TO THE WRN CWA BY NOON OR SO AS MOSTLY SHOWERS.
CONVECTION REDEVELOPS OVER NW IOWA BY EARLY AFTERNOON AS STRONG
DYNAMICS TAKE SHAPE. SBCAPE AROUND 3K J/KG COUPLED WITH STRONG
MOISTURE CONVERGENCE...60-70KTS BULK SHEAR AND LIFT FROM THE
APPROACHING SHORT WAVE SHOULD RESULT IN STRONG TO SEVERE STORMS
DEVELOPING OVER ILLINOIS AND MOVING ESE TOWARD THE SRN CWA. A 50KT
MID LEVEL JET WILL PUSH THE STORMS EWD...PERHAPS AS A DERECHO. CAN/T
ARGUE TOO MUCH WITH THE POSITION OF THE DAY ONE SLIGHT AND MODERATE
RISK AREAS. THIS ISN/T A SLAM DUNK BY ANY MEANS BUT THE HIGHEST
THREAT FOR STRONG/SVR STORMS WILL BE SOUTH OF A MUSKEGON TO LANSING
LINE. LATEST NAM ALSO PUSHES THE WARM FRONT INTO THE SRN CWA THIS
AFTERNOON. SO...WITH THE WARM FRONT IN PLACE WE CAN/T RULE OUT A
TORNADO EITHER.
THE SVR THREAT WILL END THIS EVENING AS THE LOW MOVES BY TO THE
SOUTH AND QUIETER WEATHER WILL RETURN THURSDAY AND FRIDAY.
.LONG TERM...(FRIDAY NIGHT THROUGH TUESDAY)
ISSUED AT 330 AM EDT WED JUN 12 2013
UPPER RIDGING WILL EXTEND FROM THE GULF COAST NORTH INTO THE UPPER
MID WEST FRIDAY NIGHT. THE RIDGING WILL BE FLATTENED THROUGH THE
LONG TERM AS A SERIES OF SHORTWAVE/S CREST THE RIDGE AND MOVE
THROUGH THE GREAT LAKES REGION. THE FIRST OF WHICH MOVES INTO THE
AREA ON SATURDAY. THE SECOND AND MORE SUBSTANTIAL WAVE DIGS INTO THE
GREAT LAKES REGION SUNDAY INTO MONDAY.
AT THE SURFACE RIDGING WILL BE IN PLACE FRIDAY NIGHT AND BRING DRY
WEATHER. THE HIGH SLIPS EAST QUICKLY ON SATURDAY WHICH SHOULD ALLOW
CHANCES FOR SHOWERS AND STORMS DURING THE AFTERNOON AHEAD OF THE
UPPER SHORTWAVE. THE CHANCES WILL CONTINUE INTO SATURDAY NIGHT AS A
WAVE OF LOW PRESSURE SLIDES THROUGH THE AREA AT THE SURFACE.
SUNDAY INTO MONDAY CHANCES FOR SHOWERS AND STORMS WILL CONTINUE AS
THE SECOND MORE POTENT UPPER TROUGH DIGS INTO THE GREAT LAKES.
SURFACE FEATURES ARE BIT MORE HARD TO DISCERN IN THIS TIME FRAME AS
THE GFS IS FURTHER NORTH AND DEEPER WITH THE SURFACE WAVE. FOLLOWED
THE GFS CLOSER HERE AS IT MAKES MORE SENSE TO HAVE A DEEPER FARTHER
NORTH WAVE GIVEN THE UPPER PATTERN. WE LOOK TO DRY OUT MONDAY NIGHT
INTO TUESDAY AS HIGH PRESSURE BUILDS IN.
TEMPERATURES THROUGH THE PERIOD SHOULD BE SEASONABLE DESPITE THE
RIDGING DAMPENING OUT. HEIGHTS ARE STILL FAIRLY HIGH AND 850MB TEMPS
ARE FORECAST TO BE IN THE TEENS C. HIGHS SHOULD BE IN THE UPPER 70S
TO AROUND 80 EACH DAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1145 PM EDT TUE JUN 11 2013
EXPECT FOG AND LOW CLOUDS TO FORM BY 10Z WITH SOME IFR AND EVEN
LIFR UNTIL AROUND 14Z. THEN MVFR OR VFR MOST OF THE DAY WITH
SHOWERS AND THUNDERSTORMS EXPECTED IN THE AFTERNOON AND EVENING.
SQUALL LINE SHOULD REMAIN SOUTH OF LOWER MICHIGAN WITH WINDS
REMAINING AOB 10 KNOTS FROM THE SOUTHEAST.
&&
.MARINE...
ISSUED AT 330 AM EDT WED JUN 12 2013
FAIRLY LIGHT WINDS WILL CONTINUE OVER THE LAKE RESULTING IN LOW WAVE
HEIGHTS. PATCHY DENSE FOG IS POSSIBLE DUE TO HIGH DEWPOINTS OVER THE
COLDER WATER SFC. NORTH WINDS WILL DEVELOP THURSDAY AND A SMALL
CRAFT ADVISORY MAY BE NEEDED.
&&
.HYDROLOGY...
ISSUED AT 330 AM EDT WED JUN 12 2013
THE MAIN PERIOD OF CONCERN IS THIS AFTERNOON AND EVENING. HEAVY
RAINFALL WILL BE POSSIBLE ACROSS THE SRN HALF OF THE CWA DURING THIS
TIME. AN INCH TO TWO INCHES SEEMS PLAUSIBLE ESPECIALLY SOUTH OF
I-94. THIS MAY LEAD TO LOCALIZED FLOODING.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&
$$
SYNOPSIS...93
SHORT TERM...93
LONG TERM...DUKE
AVIATION...OSTUNO
HYDROLOGY...93
MARINE...93
AREA FORECAST DISCUSSION
NWS ST LOUIS MO
340 AM CDT WED JUN 12 2013
.SHORT TERM...(THROUGH LATE THIS AFTERNOON)
ISSUED AT 337 AM CDT WED JUN 12 2013
MAIN CONCERN DEALS WITH POTENTIAL FOR SEVERE WEATHER THIS AFTERNOON
INTO THE EVENING HOURS OVER PARTS OF THE CWA IF THUNDERSTORMS ARE
ABLE TO DEVELOP. IF THUNDERSTORMS DO DEVELOP...THEN THEY WILL
LIKELY BE SEVERE...PARTICULARLY OVER NORTHEAST MISSOURI INTO CENTRAL
ILLINOIS WITH DAMAGING WIND GUSTS IN EXCESS OF 70 MPH...LARGE HAIL
AND ISOLATED TORNADOES.
EXPECT MAINLY DRY CONDITIONS THROUGH THE MORNING HOURS AS THE
THUNDERSTORM COMPLEX CURRENTLY OVER WESTERN IOWA STAYS NORTH OF THE
AREA PER THE RAP FORWARD PROPAGATION VECTORS. OBSERVED AND FORECAST
SOUNDINGS STILL SHOW A VERY PRONOUNCED WARM LAYER BETWEEN 900-650MB
THROUGH LATE AFTERNOON WHICH SHOULD LIMIT THUNDERSTORM DEVELOPMENT.
THEREAFTER...THE TAIL END OF THE TROUGH CURRENTLY OVER THE HIGH
PLAINS WILL REACH THE MISSISSIPPI RIVER WHICH WILL ACT TO WEAKEN
THIS WARM LAYER AS THE ATTENDANT COLD FRONT MOVES SOUTHEAST ACROSS
THE CWA. MOST MODEL SOUNDINGS STILL SHOW SOME CONVECTIVE INHIBITION
OR VERY NARROW POSITIVE CAPE UP TO 700MB WHICH MAY KEEP
THUNDERSTORMS NORTH AND EAST OF THE AREA. WITH THIS SAID...MID
LEVEL FORCING AND LOW LEVEL MOISTURE CONVERGENCE IS WORTH KEEPING
SCATTERED THUNDERSTORMS IN THE FORECAST LATE THIS AFTERNOON INTO THE
EVENING AS THE COLD FRONT MOVES ACROSS THE CWA. INSTABILITY AND
SHEAR PARAMETERS FAVOR SEVERE THUNDERSTORMS WITH LATE AFTERNOON
MLCAPES AROUND 3000 J/KG AND 0-6KM SHEAR OF 40-50KTS. RELATIVELY
DRY AIR BELOW 700MB FAVORS THE POTENTIAL FOR DAMAGING WINDS
GUSTS...AND THERE IS A LARGE AMOUNT OF CAPE BETWEEN -10 AND -30C
WHICH SUGGESTS THE POTENTIAL FOR LARGE HAIL. SHEAR IS LINEAR IN THE
LOWEST LEVELS...THOUGH 0-1KM SHEAR NEAR 25KTS SUGGESTS TORNADOES ARE
ALSO POSSIBLE.
DID NOT CHANGE FORECAST HIGHS TODAY AS CURRENT TEMPERATURES ARE IN
THE 70S AND THERE WILL BE DECENT MIXING UP TO 850MB TODAY WITH MORE
SUN THAN YESTERDAY.
BRITT
.LONG TERM...(TONIGHT THROUGH TUESDAY)
ISSUED AT 337 AM CDT WED JUN 12 2013
AFTERNOON/EVENING CONVECTION SHOULD BE EXITING THE AREA BY 06Z.
CANNOT RULE OUT A STRAY SHOWER OR STORM OUT AHEAD OF OR RIGHT ON THE
COLD FRONT AS IT PUSHES THROUGH EAST CENTRAL AND SOUTHEAST MISSOURI
AND SOUTHERN ILLINOIS. NORTHWEST FLOW WILL BRING COOLER AND DRIER
AIR WITH SURFACE DEWPOINTS DROPPING BACK INTO THE UPPER 50S AND
LOWER 60S. 850MB TEMPS ALSO DROP INTO THE LOW TO MID TEENS BEHIND
THE FRONT. MODELS HAVE BEEN CONSISTENTLY AMPLIFYING THE FLOW
THURSDAY INTO FRIDAY WITH A FULL LONGWAVE TROF OVER THE EAST COAST
AND THE UPPER LEVEL RIDGE BUILDING ACROSS THE GREAT PLAINS INTO THE
UPPER MIDWEST. THIS SHOULD KEEP THE LOW LEVEL RIDGE LOCKED IN
ACROSS THE MISSISSIPPI VALLEY AT LEAST THROUGH FRIDAY. SEASONABLY
COOL GUIDANCE TEMPS LOOK PRETTY REASONABLE WITH AFOREMENTIONED COOL
AND DRY RIDGE IN PLACE. THERE IS A SMALL CHANCE THAT INCREASING
WARM ADVECTION ON THE WESTERN PERIPHERY OF THE LOW LEVEL RIDGE MAY
PRODUCE ISOLATED SHOWERS OR STORMS FRIDAY OVER PARTS OF CENTRAL AND
NORTHEAST MISSOURI SO HAVE SOME SLIGHT CHANCE POPS IN THOSE AREAS.
THE WEEKEND IS LOOKING MORE AND MORE STORMY AS THE UPPER LEVEL RIDGE
BREAKS DOWN IN RESPONSE TO A SHORTWAVE WHICH IS PULLED NORTHEAST OUT
OF THE GULF OF MEXICO. THIS WAVE IS LIKELY TO HAVE QUITE A BIT OF
MOISTURE ASSOCIATED WITH IT. AM UNSURE WHAT THE POTENTIAL FOR
SEVERE WEATHER WILL BE AT THIS TIME...BUT IT DOES LOOK LIKE THERE
WILL BE THUNDERSTORMS ON AND OFF FROM SATURDAY AFTERNOON AT LEAST
THROUGH SUNDAY NIGHT OR MONDAY AND SOME LOCALLY HEAVY RAIN MAY BE
POSSIBLE. TUESDAY LOOKS DRIER AS THE WAVE MOVES EAST AND WEAK
RIDGING BUILDS BACK ACROSS THE MID MISSISSIPPI VALLEY. TEMPERATURES
THROUGH THE PERIOD LOOK TO BE NEAR NORMAL.
CARNEY
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1153 PM CDT TUE JUN 11 2013
VFR CONDITIONS ARE EXPECTED TO DOMINATE MUCH OF THE PERIOD. BOUTS
OF HIGH CLOUDS WILL CONTINUE TO IMPACT EASTERN MO AND WESTERN
ILLINOIS INTO WED MORNING. SOUTH SOUTHWESTERLY SURFACE WINDS WILL
THEN INCREASE AROUND MID-MORNING ON WEDNESDAY WITH GUSTS AOA 25
KTS. THERE IS A CHANCE OF SHOWERS AND THUNDERSTORMS ACROSS
PORTIONS OF NE MO AND WEST CENTRAL IL DURING THE LATER PART OF
WEDNESDAY AFTERNOON AND INTO THE EARLY EVENING AS A COLD FRONT
DROPS SOUTH INTO THE AREA. CONFIDENCE AT THIS TIME IS TOO LOW FOR
AN ACTUAL AIRPORT IMPACT TO INCLUDE IN THE KUIN TAF.
SPECIFICS FOR KSTL...
VFR CONDITIONS ARE EXPECTED TO DOMINATE MUCH OF THE PERIOD WITH
BOUTS OF HIGH CLOUDS CONTINUING OVERNIGHT THROUGH WEDNESDAY
MORNING. SOUTH SOUTHWESTERLY SURFACE WINDS WILL THEN INCREASE
AROUND MID-MORNING ON WEDNESDAY WITH GUSTS AOA 25 KTS. A COLD
FRONT WILL BE DROPPING INTO EASTERN MO ON WEDNESDAY EVENING AND IT
COULD BE ACCOMPANIED BY SCATTERED THUNDERSTORMS. IF THERE IS ANY
IMPACT AT KSTL...CURRENT INDICATIONS ARE THAT 04-07Z WOULD BE THE
OPTIMAL TIME FRAME...HOWEVER CONFIDENCE IS TOO LOW TO MENTION AT
THIS TIME.
GLASS
&&
.PRELIMINARY POINT TEMPS/POPS...
SAINT LOUIS 96 70 86 65 / 30 40 5 5
QUINCY 92 64 81 60 / 50 40 0 5
COLUMBIA 95 68 84 64 / 10 20 0 10
JEFFERSON CITY 96 69 84 65 / 10 10 0 10
SALEM 95 70 82 61 / 30 50 5 0
FARMINGTON 95 68 84 60 / 10 30 5 5
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
242 AM CDT WED JUN 12 2013
.DISCUSSION...
LOW PRESSURE WAS LOCATED OVER SOUTH CENTRAL NEBRASKA AT 07Z
WITH A COLD FRONT TRAILING INTO WESTERN KANSAS AND A WARM FRONT
EXTENDING ACROSS SOUTHEAST NEBRASKA AND SOUTHWEST IOWA. CONVECTION
WAS ONGOING OVER EASTERN NEBRASKA INTO WEST CENTRAL AND NORTHWEST
IOWA.
LATEST HRRR MODEL TRACKS THE SURFACE LOW EAST TOWARD SOUTHWEST
IOWA THIS MORNING WITH THE COLD FRONT MOVING THROUGH THE AREA BY
18Z. CURRENT CONVECTION IS EXPECTED TO PUSH EAST OF THE AREA BY
THIS SAME TIME IN ADVANCE OF THE LOW AND NORTH OF THE WARM FRONT.
HIGH PRESSURE THEN BUILDS INTO THE PLAINS REGION THIS AFTERNOON
AND TONIGHT. AS THE HIGH MOVES EAST INTO THE MISSISSIPPI VALLEY
ON THURSDAY SOUTHERLY FLOW RETURNS TO THE PLAINS ALONG WITH A WARM
ADVECTION PATTERN AND THE CHANCE OF THUNDERSTORMS FOR THURSDAY
NIGHT INTO FRIDAY MORNING. AS ANOTHER STRONG UPPER WAVE MOVES INTO
THE NORTHERN PLAINS ON FRIDAY A COLD FRONT MOVES INTO THE AREA
AGAIN FRIDAY NIGHT WITH ANOTHER CHANCE OF STORMS FOR THE AREA.
EXTENDED MODELS STILL SHOW SOME POTENTIAL FOR ADDITIONAL STORMS
SATURDAY INTO SUNDAY. WITH THE UPPER PATTERN REMAINING STRONG AND
ACTIVE THROUGH MID WEEK PERIODS OF STORMS STILL INDICATED FOR THE
AREA DURING THIS TIME.
&&
.AVIATION...
06Z TAFS FOR KOFK...KOMA AND KLNK.
GOING TAF IN GOOD SHAPE...THUS NO SIGNIFICANT CHANGES MADE. AVN
CONCERNS STILL FOCUSED ON KOFK. AREA OF TSRA WAS MOVING INTO NERN
NEB ALONG A NEAR-STATIONARY SFC BNDRY. THIS HAVE MAINTAINED TEMP
GROUP IN ANTICIPATION OF CONVECTION MOVING THRU. HOWEVER...STORM
TRAJECTORY PER RADAR TRENDS THE LAST HOUR SUGGEST IT IS POSSIBLE TSRA
ACTIVITY COULD REMAIN JUST NE OF KOFK. DO NOT EXPECT ANY TSRA
ACTIVITY AT KOMA/KLNK. OTHERWISE...COLD FRONTAL PASSAGE WILL SWING
SFC WINDS TO THE NW LATER THIS MORNING WITH GUSTS 20-25KT THRU THE
AFTN HOURS.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
FOBERT/DEE
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
1222 AM CDT WED JUN 12 2013
.SYNOPSIS...
ISSUED AT 300 PM CDT TUE JUN 11 2013
H5 ANALYSIS THIS MORNING...AS A RIDGE EXTENDING FROM
TEXAS...NORTH INTO THE EASTERN DAKOTAS. WEST OF THE RIDGE...A STRONG
SHORTWAVE WAS LOCATED OVER NORTHERN NEVADA WITH A CLOSED LOW NOTED
OFF THE COAST OF BRITISH COLUMBIA. WV IMAGERY AS OF 18Z HAS THE NRN
NEVADA SHORTWAVE...ENTERING FAR SWRN WYOMING. LIGHTNING STRIKES
AND CONVECTION HAS DEVELOPED ACROSS SWRN MT AND NWRN WYOMING IN
ADVANCE OF THIS FEATURE. AT THE SURFACE A FRONTAL BOUNDARY
EXTENDED FROM CENTRAL WYOMING...SE INTO NRN COLORADO...THEN EAST
INTO SRN NEBRASKA. ALONG AND SOUTH OF THIS BOUNDARY...TEMPERATURES
HAVE SURGED INTO THE UPPER 90S AND LOWER 100S. NORTH OF THE
BOUNDARY...TEMPERATURES WERE IN 80S. DEEP EASTERLY FLOW WAS
PRESENT NORTH OF THE FRONT AND HAS PUSHED DEW POINTS INTO THE
UPPER 50S TO UPPER 60S THIS AFTERNOON...WITH THE HIGHEST DEW
POINTS NOTED OVER NORTHERN NEBRASKA. AS OF 2 PM CDT DEW
POINTS...RANGED FROM 63 AT PINE RIDGE...TO 68 AT ONEILL.
&&
.SHORT TERM...(THIS AFTERNOON THROUGH WEDNESDAY)
ISSUED AT 300 PM CDT TUE JUN 11 2013
TONIGHT AND WEDNESDAY...MAIN FORECASTING CHALLENGE IS
THUNDERSTORM CHANCES AND SEVERE POTENTIAL TONIGHT. TOWARD 00Z THIS
EVENING...A DECENT SHORTWAVE WILL APPROACH THE PANHANDLE WITH TSRA
INITIATION DURING THE 22Z TO 00Z TIME FRAME. THE HI RES RUC...AS
WELL AS THE 12Z NAM SOLN...DEVELOPS ISOLD TSRAS IN THE NERN
PANHANDLE...AND SWRN NEBRASKA AROUND 22Z THIS AFTERNOON. ACTIVITY IN
THE SWRN CWA SHEARS OFF AND DISSIPATES QUICKLY BY 01Z. FURTHER
NORTH...ACTIVITY IS EXPECTED TO PERSIST INTO THE EVENING HOURS...DUE
TO A COMBINATION OF BETTER SUPPORT ALOFT AND DEEPER...RICHER
BOUNDARY LAYER MOISTURE IN NORTHERN NEBRASKA...WHERE DEWPOINTS WILL
REACH THE MID 60S TO AROUND 70 BY THIS EVENING. A TORNADO THREAT
WILL EXIST INITIALLY IN THE NWRN CWA WITH DECENT DEEP LAYER
SHEAR...LOWERED LCL HTS...AND THE PRESENCE OF A WEAK LOW LEVEL
BOUNDARY. BASED ON THE LATEST HRRR AND 4KM WRF
SOLNS...SHERIDAN...AND WESTERN CHERRY COUNTIES HAVE THE HIGHEST RISK
OF SEEING A DISCRETE SUPERCELL...AND THUS THE HIGHEST TORNADO THREAT
EARLY THIS EVENING. THE TORNADO THREAT WILL DECREASE BY MID EVENING
AS A STRONG FAST MOVING MCS DEVELOPS OVER THE BLACK HILLS AND RACES
EAST OVERNIGHT. THE THREAT FOR STRONG DAMAGING WINDS WILL BE HIGHEST
ACROSS FAR NORTHERN NEBRASKA INTO THE OVERNIGHT AS THIS WILL BE ON
THE SRN PERIPHERY OF THE MCS. AS THE MCS TRACKS INTO SRN MN/NRN IA
OVERNIGHT TONIGHT...A COLD FRONT WILL DROP SOUTH INTO WESTERN AND
NORTH CENTRAL NEBRASKA...WITH HIGH PRESSURE BUILDING INTO NERN
NEBRASKA FOR WEDNESDAY. COOLER TEMPS AND PARTLY TO MOSTLY CLOUDY
SKIES WILL PUSH INTO NERN AND CENTRAL PORTIONS OF THE FORECAST AREA
WEDNESDAY WITH HIGHS RANGING FROM THE UPPER 70S TO MIDDLE 80S.
ACROSS FAR SWRN NEBRASKA...HIGHS WILL TOP OUT NEAR 90.
.LONG TERM...(WEDNESDAY NIGHT THROUGH MONDAY)
ISSUED AT 300 PM CDT TUE JUN 11 2013
MODELS HAVE COME INTO BETTER AGREEMENT IN MID AND LONG TERM
FORECASTS. HEAT TO HANG AROUND WITH SUMMER BEGINNING EARLY. STRONG
RIDGE OVER SOUTHERN INTO NORTHERN PLAINS WILL KEEP JET STREAM WELL
NORTH. H5 SYSTEMS MOVING OUT OF THE GULF OF ALASKA WILL TRY TO
FLATTEN RIDGE OVER NORTHERN PLAINS BUT MAIN ENERGY WILL BE PUSHED
TO THE CANADIAN US BORDER WITH WEAKER WAVES MOVING UNDER THE
RIDGE. WITH AFTERNOON HEATING AND INSTABILITY INCREASING LATE
AFTERNOON THUNDERSTORMS FIRING ALONG THE FRONT RANGE AND MOVING
EAST INTO WESTERN NEBRASKA IN A RING OF FIRE PATTERN. NAM HAS BEEN
HANDLING HEAT FAR BETTER THAN OTHER MODELS AS OF LATE AND WILL
LEAN TOWARDS NAM SOLUTIONS AS FAR AS HIGH TEMPERATURES. SURFACE
HIGH PRESSURE BUILDING INTO WESTERN NEBRASKA WEDNESDAY EVENING. SOME
CLEARING HAVE KEPT TEMPERATURES IN THE MID TO UPPER 50S WITH 15C
850MB TEMPERATURES OVER HEAD. WARM AIR ADVECTION OVER WESTERN
NEBRASKA THROUGH THE DAY ON THURSDAY. UPSLOPE FLOW AND WAVE
MOVING THROUGH HAVE RETAINED POPS. FRIDAY LOOKS TO WARM UP INTO
THE 90S ONCE AGAIN WITH SOME WARMER TEMPERATURES OVER SOUTHWEST
NEBRASKA NEAR IMPERIAL. 850MB TEMPS 30C AND GREATER ONCE AGAIN.
THUNDERSTORMS TO LINGER INTO THE DAY ON FRIDAY WITH BOUNDARY LYING
ACROSS FORECAST AREA. WARM TEMPERATURES AT 700MB INDICATIVE OF
STRONG CAP AND POPS MAY HAVE TO BE REDUCED IN LATER FORECASTS.
EVEN WITH COOLER TEMPERATURES SATURDAY BEHIND FRONT BOUNDARY
CONTINUES TO LAY ACROSS FORECAST AREA AND STRONG MOISTURE
ADVECTION HAVE RETAINED THUNDERSTORMS LATE AFTERNOON AND EVENING.
THUNDERSTORMS IN THE FORECAST AGAIN ON SUNDAY AS SYSTEM DROPS OUT
OF CANADA ACROSS MINNESOTA. BETTER CHANCES OVER EASTERN PORTIONS
OF THE FORECAST AREA. NORMAL TEMPERATURES IN THE 80S THROUGH THE
FIRST PART OF THE WORK WEEK WITH CHANCES FOR THUNDERSTORMS MAINLY
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1221 AM CDT WED JUN 12 2013
STORMS ARE LIKELY TO CONTINUE IN NORTHERN NEBRASKA UNTIL ABOUT 09Z.
THERE IS ONLY A NARROW WINDOW...06-08Z...IN WHICH THE SOUTHWEST WILL
HAVE ANY CHANCE OF STORMS. AS A RESULT...WE HAVE LEFT THUNDER OUT OF
THE FORECAST FOR LBF...BUT LEFT A MENTION IN THE FORECAST FOR VTN.
AFTER 09Z...THERE IS AGAIN A POSSIBILITY OF PATCHY FOG IN THE LBF
AREA UNLESS DRIER AIR PUSHES IN AS IT DID LAST NIGHT. WITH WIND
CONTINUING OUT OF THE EAST TO NORTHEAST...I DO NOT EXPECT THE AIR TO
DRY OUT.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...CLB
SHORT TERM...CLB
LONG TERM...POWER
AVIATION...SPRINGER
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1220 AM CDT WED JUN 12 2013
.UPDATE...
ISSUED AT 1133 PM CDT TUE JUN 11 2013
UPDATED THE HWO TO REMOVE WIND ADVISORY AND HEAT INDEX WORDING. AS
OF 04Z KUEX AND KLNX INDICATED ISOLATED TO SCATTERED THUNDERSTORM
ACTIVITY OVER PORTIONS OF CENTRAL NEBRASKA...WITH MUCH OF THIS
ACTIVITY REMAINING JUST NORTHWEST OF OUR AREA. IN
ADDITION...INTENSE CONVECTION CONTINUES OVER THE NORTHERN HIGH
PLAINS. GUIDANCE CONTINUES TO SUGGEST AN INTENSE 850MB JET STREAK
OF 60-70KTS WILL SET UP OVER OUR AREA TONIGHT. THANKFULLY THIS LOW
LEVEL JET SHOULD SHIFT EAST...AWAY FROM OUR AREA DURING THE 06-12Z
TIME PERIOD...BUT THERE IS SOME CONCERN THE INTENSE CONVECTION TO
OUR NORTHWEST COULD LATCH ON TO THE AXIS OF LOW LEVEL THERMAL
ADVECTION ALONG THE LOW LEVEL JET THUS ALLOWING THE THUNDERSTORM
ACTIVITY TO SURGE INTO OUR AREA. CURRENT FORECAST ALREADY HAS ~20%
POPS ACROSS OUR CWA AND THIS SEEMS REASONABLE FOR THE TIME BEING.
THE EXTREMELY WARM LOW TO MID LEVEL WARM AIRMASS HAS PUSHED
FREEZING HEIGHTS CLOSE TO 15000FT AGL ACROSS MUCH OF OUR
AREA...THUS SUGGESTING AN UPDRAFT WOULD HAVE TO BE STRONG ENOUGH
TO PUSH A PRECIPITATION MASS CLOSE TO 40000FT AGL FOR SEVERE HAIL
TO BE REALIZED. AS A RESULT...HAIL IS NOT A PRIMARY CONCERN
TONIGHT. THAT BEING SAID...PROXIMITY SOUNDINGS FROM THE ACROSS OUR
CWA...PER LAPS AND RAP ANALYSIS...AS WELL AS 00Z SOUNDING DATA
FROM KBLF...SUGGEST A VERY DRY LOW TO MID TROPOSPHERIC AIRMASS IS
IN PLACE. MUCH LIKE LAST NIGHT...IF A PRECIPITATION MASS CAN
EFFECTIVELY COOL THROUGH EVAPORATION AND GAIN SIGNIFICANT MOMENTUM
TOWARDS THE SURFACE...A STRONG THUNDERSTORM WIND GUST WILL
CERTAINLY BE POSSIBLE. OBVIOUSLY...IF THE INTENSE CONVECTION OVER
THE NORTHERN HIGH PLAINS CAN SUSTAIN ITSELF DOWN THIS WAY...THEN
THERE WILL BE THE CHANCE OF AN QLCS WORKING ACROSS THE AREA WHICH
WILL CERTAINLY PROVIDE A THREAT FOR STRONG WIND. DO WANT TO
EMPHASIZE THAT ALL OF THESE THREATS ARE VERY MARGINAL AND THAT THE
OVERALL THE THREAT FOR SEVERE WEATHER SEEMS VERY LOW FOR
TONIGHT...BUT STILL SOMETHING TO CONTINUE MONITORING. OVERALL THE
GOING FORECAST FOR TONIGHT REMAINS IN GREAT SHAPE WITH NO
SIGNIFICANT CHANGES MADE AT THIS TIME.
&&
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 350 PM CDT TUE JUN 11 2013
AN UPPER LEVEL DISTURBANCE CROSSING THE INTERMOUNTAIN WEST THIS
AFTERNOON WILL CONTINUE TO TRANSITION AND CUT INTO THE UPPER LEVEL
RIDGE ON WEDNESDAY...HELPING TO STEER A WEAK COLD FRONT TO OUR NORTH
ACROSS THE LOCAL AREA OVERNIGHT TONIGHT. AS A RESULT...EXPECT
AFTERNOON TEMPERATURES TO FALL SIGNIFICANTLY ACROSS MUCH OF THE
LOCAL AREA ON WEDNESDAY...RETURNING TO NEAR OR JUST ABOVE
CLIMATOLOGICAL VALUES.
IN THE MEANTIME...ALREADY SEEING A COUPLE OF SHOWERS DEVELOP
ACROSS NORTHWESTERN KANSAS THIS AFTERNOON...WHICH ARE EXPECTED TO
SLOWLY DRIFT TOWARDS THE LOCAL AREA LATE THIS AFTERNOON AND
EVENING. WHILE A SIGNIFICANT CAP REMAINS IN PLACE...PLENTY OF
INSTABILITY EXISTS IF A FEW STORMS ARE ABLE TO DEVELOP FOR SOME
STRONG WIND GUSTS AND POSSIBLY MARGINALLY SEVERE HAIL...SOME OF
WHICH IS CAPTURED BY LATEST HRRR AND 12Z WRF. EVEN SO...THE BEST
CHANCE FOR DEVELOPMENT...SEVERE OR OTHERWISE...IS EXPECTED TO BE
ACROSS THE NORTHERN TIER OF COUNTIES OVERNIGHT...AS THIS AREA WILL
BE NEAR THE APPROACHING COLD FRONT AND IN THE AXIS OF THE
DEVELOPING LOW LEVEL JET. SO WHILE THE SEVERE POTENTIAL WILL BE
FOCUSED PRIMARILY WEST OF HIGHWAY 281 LATE THIS AFTERNOON AND
EARLY EVENING...EXPECT THUNDERSTORM POTENTIAL TO SHIFT NORTH
OVERNIGHT...WHERE A FEW OF OUR COUNTIES ARE HIGHLIGHTED IN SLIGHT
RISK FOR SEVERE WEATHER FROM SPC.
OTHERWISE...EXPECT A FAIRLY NICE...BUT BREEZY DAY...ACROSS THE
REGION ON WEDNESDAY...AS SKIES WILL CLEAR BEHIND THE PASSING FRONT
AND TEMPERATURES WILL BE SIGNIFICANTLY COOLER THAN THIS AFTERNOONS
VALUES.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 350 PM CDT TUE JUN 11 2013
ALOFT: GLOBAL MODELS AND THEIR ENSEMBLES ARE IN EXCELLENT AGREEMENT
ON THE LONG-WAVE /LGWV/ FLOW THRU THE FCST PERIOD AND EVEN THRU DAY
10 /JUN 20TH/. THE GENERAL PATTERN WILL FEATURE A RIDGE OVER THE
PLAINS WITH TROFS ON BOTH COASTS. THE CLOSED LOW CURRENTLY MILLING
AROUND OFF BRITISH COLUMBIA WILL GET SLOWLY KICKED INTO THE PAC NW
WED-THU AND KNOCK DOWN THE RIDGE FRI-SAT BEFORE EMERGING INTO AND
DEEPENING THE ERN USA TROF. THIS WILL FORCE THE RIDGE TO RETROGRADE
INTO THE ROCKIES AS IT REBUILDS. THE INITIAL INDICATIONS ARE THAT
THE RIDGE WILL ADVANCE BACK INTO THE PLAINS THE MIDDLE OF NEXT WEEK
AS THE NEXT NE PAC LOW MOVES ONSHORE.
SFC: THE COOL FRONT MOVES THRU WED WILL SINK TO THE KS-OK BORDER BY
DAWN THU...WITH CANADIAN HIGH PRES BUILDING S INTO THE REGION. THE
ADVANCE OF THE UPR LOW AND THE PV ANOMALIES ORBITING IT WILL
INITIATE A NEW LEE LOW THU NGT...WITH THE FRONT LIFTING BACK N. THIS
WILL SPREAD THE 90+ HEAT BACK N INTO S-CNTRL NEB FRI. THE COOL FRONT
ASSOCIATED WITH THE ADVANCING PAC NW UPR LOW WILL ARRIVE HERE FRI
NGT AND WASH OUT. AS THE REMNANTS OF UPR LOW DROP INTO THE ERN USA
TROF EARLY NEXT WEEK...A MUCH STRONGER COOL FRONT WILL MOVE THRU SUN
NGT.
THE DAILY DETAILS...
THU: QUIET WITH TEMPS CLOSE TO NORMAL. COULD SEE AN EVNG SHWR/TSTM
DRIFT IN FROM NW KS OR WRN NEB.
THU NGT: COULD SEE AN MCS ROLL THRU HERE OR NEARBY AS LLJ PUNCHES
OVER THE LIFTING WARM FRONT.
FRI: HOT AND BREEZY IN THE WARM SECTOR. IF AN MCS OCCURS IT WILL
REINFORCE AND SLOW OR STALL THE WARM FRONT. TEMPS COULD BUST IF
COOL/CLOUDY CONDITIONS LINGER. THE WARM FRONT COULD ALSO BE A FOCUS
FOR RENEWED LATE DAY TSTM DEVELOPMENT.
FRI NGT: STRONG CONVERGENCE WITH PASSAGE OF COOL FRONT. THIS COULD
BE A DECENT OPPORTUNITY FOR TSTMS WHERE PARCELS CAN REACH THE LFC.
SAT-SUN: NEAR NORMAL TEMPS AND DRY MOST OF THE TIME. HOWEVER...
THERE WILL BE A RISK OF TSTMS EACH DAY...HIGHEST PROBABILITY BETWEEN
4PM-4AM. AT THIS POINT BELIEVE THE BEST CHANCE FOR ORGANIZED/
WIDESPREAD TSTMS WILL BE SUN AFTN-NGT.
MON: PROBABLY ENDS UP DRY AS AMPLIFYING ERN USA TROF WILL TAKE THE
COOL FRONT FARTHER S THAN ITS PREDECESSORS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1220 AM CDT WED JUN 12 2013
MAIN AREA OF THUNDERSTORMS REMAINS WELL TO THE NORTH OF THE KGRI
TERMINAL AREA BUT THERE HAVE BEEN SOME SHOWERS AND ISOLATED
THUNDERSTORMS THAT DEVELOPED TO THE WEST. THESE HAVE MAINLY
DISSIPATED AND DO NOT EXPECT ANYTHING AT THE KGRI TERMINAL. A
SURFACE LOW AND COLD FRONT TO THE WEST IS EXPECTED TO MOVE THROUGH
IN THE NEXT COUPLE HOURS AND GUSTY WINDS FROM THE SOUTH WILL GIVE
WAY TO NORTH WINDS. WINDS WILL INCREASE SOME DURING THE DAY
WEDNESDAY.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
UPDATE...BRYANT
SHORT TERM...SAR
LONG TERM...HALBLAUB
AVIATION...JCB
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1133 PM CDT TUE JUN 11 2013
.UPDATE...
ISSUED AT 1133 PM CDT TUE JUN 11 2013
UPDATED THE HWO TO REMOVE WIND ADVISORY AND HEAT INDEX WORDING. AS
OF 04Z KUEX AND KLNX INDICATED ISOLATED TO SCATTERED THUNDERSTORM
ACTIVITY OVER PORTIONS OF CENTRAL NEBRASKA...WITH MUCH OF THIS
ACTIVITY REMAINING JUST NORTHWEST OF OUR AREA. IN
ADDITION...INTENSE CONVECTION CONTINUES OVER THE NORTHERN HIGH
PLAINS. GUIDANCE CONTINUES TO SUGGEST AN INTENSE 850MB JET STREAK
OF 60-70KTS WILL SET UP OVER OUR AREA TONIGHT. THANKFULLY THIS LOW
LEVEL JET SHOULD SHIFT EAST...AWAY FROM OUR AREA DURING THE 06-12Z
TIME PERIOD...BUT THERE IS SOME CONCERN THE INTENSE CONVECTION TO
OUR NORTHWEST COULD LATCH ON TO THE AXIS OF LOW LEVEL THERMAL
ADVECTION ALONG THE LOW LEVEL JET THUS ALLOWING THE THUNDERSTORM
ACTIVITY TO SURGE INTO OUR AREA. CURRENT FORECAST ALREADY HAS ~20%
POPS ACROSS OUR CWA AND THIS SEEMS REASONABLE FOR THE TIME BEING.
THE EXTREMELY WARM LOW TO MID LEVEL WARM AIRMASS HAS PUSHED
FREEZING HEIGHTS CLOSE TO 15000FT AGL ACROSS MUCH OF OUR
AREA...THUS SUGGESTING AN UPDRAFT WOULD HAVE TO BE STRONG ENOUGH
TO PUSH A PRECIPITATION MASS CLOSE TO 40000FT AGL FOR SEVERE HAIL
TO BE REALIZED. AS A RESULT...HAIL IS NOT A PRIMARY CONCERN
TONIGHT. THAT BEING SAID...PROXIMITY SOUNDINGS FROM THE ACROSS OUR
CWA...PER LAPS AND RAP ANALYSIS...AS WELL AS 00Z SOUNDING DATA
FROM KBLF...SUGGEST A VERY DRY LOW TO MID TROPOSPHERIC AIRMASS IS
IN PLACE. MUCH LIKE LAST NIGHT...IF A PRECIPITATION MASS CAN
EFFECTIVELY COOL THROUGH EVAPORATION AND GAIN SIGNIFICANT MOMENTUM
TOWARDS THE SURFACE...A STRONG THUNDERSTORM WIND GUST WILL
CERTAINLY BE POSSIBLE. OBVIOUSLY...IF THE INTENSE CONVECTION OVER
THE NORTHERN HIGH PLAINS CAN SUSTAIN ITSELF DOWN THIS WAY...THEN
THERE WILL BE THE CHANCE OF AN QLCS WORKING ACROSS THE AREA WHICH
WILL CERTAINLY PROVIDE A THREAT FOR STRONG WIND. DO WANT TO
EMPHASIZE THAT ALL OF THESE THREATS ARE VERY MARGINAL AND THAT THE
OVERALL THE THREAT FOR SEVERE WEATHER SEEMS VERY LOW FOR
TONIGHT...BUT STILL SOMETHING TO CONTINUE MONITORING. OVERALL THE
GOING FORECAST FOR TONIGHT REMAINS IN GREAT SHAPE WITH NO
SIGNIFICANT CHANGES MADE AT THIS TIME.
&&
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 350 PM CDT TUE JUN 11 2013
AN UPPER LEVEL DISTURBANCE CROSSING THE INTERMOUNTAIN WEST THIS
AFTERNOON WILL CONTINUE TO TRANSITION AND CUT INTO THE UPPER LEVEL
RIDGE ON WEDNESDAY...HELPING TO STEER A WEAK COLD FRONT TO OUR NORTH
ACROSS THE LOCAL AREA OVERNIGHT TONIGHT. AS A RESULT...EXPECT
AFTERNOON TEMPERATURES TO FALL SIGNIFICANTLY ACROSS MUCH OF THE
LOCAL AREA ON WEDNESDAY...RETURNING TO NEAR OR JUST ABOVE
CLIMATOLOGICAL VALUES.
IN THE MEANTIME...ALREADY SEEING A COUPLE OF SHOWERS DEVELOP
ACROSS NORTHWESTERN KANSAS THIS AFTERNOON...WHICH ARE EXPECTED TO
SLOWLY DRIFT TOWARDS THE LOCAL AREA LATE THIS AFTERNOON AND
EVENING. WHILE A SIGNIFICANT CAP REMAINS IN PLACE...PLENTY OF
INSTABILITY EXISTS IF A FEW STORMS ARE ABLE TO DEVELOP FOR SOME
STRONG WIND GUSTS AND POSSIBLY MARGINALLY SEVERE HAIL...SOME OF
WHICH IS CAPTURED BY LATEST HRRR AND 12Z WRF. EVEN SO...THE BEST
CHANCE FOR DEVELOPMENT...SEVERE OR OTHERWISE...IS EXPECTED TO BE
ACROSS THE NORTHERN TIER OF COUNTIES OVERNIGHT...AS THIS AREA WILL
BE NEAR THE APPROACHING COLD FRONT AND IN THE AXIS OF THE
DEVELOPING LOW LEVEL JET. SO WHILE THE SEVERE POTENTIAL WILL BE
FOCUSED PRIMARILY WEST OF HIGHWAY 281 LATE THIS AFTERNOON AND
EARLY EVENING...EXPECT THUNDERSTORM POTENTIAL TO SHIFT NORTH
OVERNIGHT...WHERE A FEW OF OUR COUNTIES ARE HIGHLIGHTED IN SLIGHT
RISK FOR SEVERE WEATHER FROM SPC.
OTHERWISE...EXPECT A FAIRLY NICE...BUT BREEZY DAY...ACROSS THE
REGION ON WEDNESDAY...AS SKIES WILL CLEAR BEHIND THE PASSING FRONT
AND TEMPERATURES WILL BE SIGNIFICANTLY COOLER THAN THIS AFTERNOONS
VALUES.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 350 PM CDT TUE JUN 11 2013
ALOFT: GLOBAL MODELS AND THEIR ENSEMBLES ARE IN EXCELLENT AGREEMENT
ON THE LONG-WAVE /LGWV/ FLOW THRU THE FCST PERIOD AND EVEN THRU DAY
10 /JUN 20TH/. THE GENERAL PATTERN WILL FEATURE A RIDGE OVER THE
PLAINS WITH TROFS ON BOTH COASTS. THE CLOSED LOW CURRENTLY MILLING
AROUND OFF BRITISH COLUMBIA WILL GET SLOWLY KICKED INTO THE PAC NW
WED-THU AND KNOCK DOWN THE RIDGE FRI-SAT BEFORE EMERGING INTO AND
DEEPENING THE ERN USA TROF. THIS WILL FORCE THE RIDGE TO RETROGRADE
INTO THE ROCKIES AS IT REBUILDS. THE INITIAL INDICATIONS ARE THAT
THE RIDGE WILL ADVANCE BACK INTO THE PLAINS THE MIDDLE OF NEXT WEEK
AS THE NEXT NE PAC LOW MOVES ONSHORE.
SFC: THE COOL FRONT MOVES THRU WED WILL SINK TO THE KS-OK BORDER BY
DAWN THU...WITH CANADIAN HIGH PRES BUILDING S INTO THE REGION. THE
ADVANCE OF THE UPR LOW AND THE PV ANOMALIES ORBITING IT WILL
INITIATE A NEW LEE LOW THU NGT...WITH THE FRONT LIFTING BACK N. THIS
WILL SPREAD THE 90+ HEAT BACK N INTO S-CNTRL NEB FRI. THE COOL FRONT
ASSOCIATED WITH THE ADVANCING PAC NW UPR LOW WILL ARRIVE HERE FRI
NGT AND WASH OUT. AS THE REMNANTS OF UPR LOW DROP INTO THE ERN USA
TROF EARLY NEXT WEEK...A MUCH STRONGER COOL FRONT WILL MOVE THRU SUN
NGT.
THE DAILY DETAILS...
THU: QUIET WITH TEMPS CLOSE TO NORMAL. COULD SEE AN EVNG SHWR/TSTM
DRIFT IN FROM NW KS OR WRN NEB.
THU NGT: COULD SEE AN MCS ROLL THRU HERE OR NEARBY AS LLJ PUNCHES
OVER THE LIFTING WARM FRONT.
FRI: HOT AND BREEZY IN THE WARM SECTOR. IF AN MCS OCCURS IT WILL
REINFORCE AND SLOW OR STALL THE WARM FRONT. TEMPS COULD BUST IF
COOL/CLOUDY CONDITIONS LINGER. THE WARM FRONT COULD ALSO BE A FOCUS
FOR RENEWED LATE DAY TSTM DEVELOPMENT.
FRI NGT: STRONG CONVERGENCE WITH PASSAGE OF COOL FRONT. THIS COULD
BE A DECENT OPPORTUNITY FOR TSTMS WHERE PARCELS CAN REACH THE LFC.
SAT-SUN: NEAR NORMAL TEMPS AND DRY MOST OF THE TIME. HOWEVER...
THERE WILL BE A RISK OF TSTMS EACH DAY...HIGHEST PROBABILITY BETWEEN
4PM-4AM. AT THIS POINT BELIEVE THE BEST CHANCE FOR ORGANIZED/
WIDESPREAD TSTMS WILL BE SUN AFTN-NGT.
MON: PROBABLY ENDS UP DRY AS AMPLIFYING ERN USA TROF WILL TAKE THE
COOL FRONT FARTHER S THAN ITS PREDECESSORS.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING)
ISSUED AT 550 PM CDT TUE JUN 11 2013
WIND WILL BE TRICKY FOR THIS FORECAST AS A NEARLY STATIONARY FRONT
LIES JUST TO THE SOUTH...AFFECTING WIND DIRECTION AND SPEED. BEST
GUESS WILL BE A DIRECTION FROM THE SOUTHEAST AS THE TERMINAL
SHOULD BE JUST NORTH OF THE BOUNDARY...WITH A DECREASE SHORTLY
INTO THE FORECAST. A COLD FRONT SHOULD CHANGE THE WIND DIRECTION
LATE TONIGHT TO THE NORTH NORTHWEST AFTER A COLD FRONT COMES
THROUGH AND AN INCREASE TO WIND SPEEDS...ESPECIALLY AS MIXING
INCREASES. VFR CONDITIONS ARE ANTICIPATED AND ONLY A SLIGHT CHANCE
OF THUNDERSTORMS EXISTS FOR TONIGHT. WITH SUCH A LOW
CHANCE...THUNDERSTORMS WERE LEFT OUT OF THE FORECAST.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
UPDATE...BRYANT
SHORT TERM...SAR
LONG TERM...HALBLAUB
AVIATION...HEINLEIN
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
144 AM EDT WED JUN 12 2013
.SYNOPSIS...
A WEAK DISTURBANCE WILL MOVE THROUGH TONIGHT BRINGING SOME
THUNDERSTORMS TO THE AREA. STRONG LOW PRESSURE CONTAINING COPIOUS
MOISTURE WILL BRING THUNDERSTORMS WEDNESDAY INTO THURSDAY. HIGH
PRESSURE AND DRY AIR WILL ARRIVE ON FRIDAY.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
CONVECTION THAT DEVELOPED OVER NRN IL AND INDIANA AND DROPPED
INTO THE FA IS QUICKLY MOVG SE AND ALSO WEAKENING. LATEST RAP AND
HRRR RUNS ARE NOW DELAYING ADDITIONAL OVERNIGHT CONVECTION UNTIL
AROUND 09Z...SO LOWERED THE POPS UNTIL THEN. THE CONVECTION ALSO
LOOKS A LITTLE MORE SCATTERED...SO LOWER POPS TONIGHT.
OVERNIGHT LOWS WILL NOT DROP TOO MUCH...ONLY FALLING INTO THE
UPPER 60S.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH THURSDAY NIGHT/...
LOW PRESSURE WILL BE MOVING FROM THE GREAT PLAINS TO THE
MISSISSIPPI VALLEY DURING THE DAY ON WEDNESDAY. A WARM FRONT WILL
EXTEND FROM THE LOW ACROSS NORTHERN OHIO...LEAVING THE ILN AREA IN
THE WARM SECTOR OF THE LOW. NUMEROUS THUNDERSTORMS ARE EXPECTED TO
DEVELOP BY WEDNESDAY AFTERNOON IN FAR NORTHERN COUNTIES CLOSE TO
THE BOUNDARY...WITH SCATTERED TO ISOLATED STORMS FARTHER SOUTH
WHERE A CAP IS EXPECTED TO INHIBIT CONVECTION. IN AN ENVIRONMENT
OF MODERATE INSTABILITY AND SHEAR...SEVERE THUNDERSTORMS WILL BE
POSSIBLE WEDNESDAY AFTERNOON. HIGH TEMPERATURES AROUND 90
COMBINING WITH DEW POINTS NEAR 70 WILL RESULT IN HEAT INDICES NEAR 95.
THE LOW WILL BE TRAVELING ACROSS NORTHERN INDIANA TO NORTHWEST
OHIO WEDNESDAY NIGHT...SUPPORTED BY AN UPPER TROUGH. THIS SCENARIO
WILL BRING THUNDERSTORMS TO MOST IF NOT ALL OF THE AREA BY
THURSDAY MORNING. THE THUNDERSTORMS WILL HAVE A GOOD AMOUNT OF
INSTABILITY TO TAP INTO...AND STRONG WIND FIELDS INCLUDING A 50
KNOT LOW LEVEL JET WILL AID IN STORM ORGANIZATION. DAMAGING WIND
GUSTS AND LARGE HAIL ARE EXPECTED WITH SOME OF THE THUNDERSTORMS.
WITH MODELS SHOWING FAVORABLE HELICITY PROFILES...ISOLATED
TORNADOES WILL ALSO BE POSSIBLE. HEAVY RAIN IS ALSO VERY LIKELY IN
A REGIME OF COPIOUS MOISTURE...ESPECIALLY TOWARD THURSDAY MORNING
WHEN THUNDERSTORMS CELLS AND LINE SEGMENTS MAY MERGE INTO A LARGE
THUNDERSTORM COMPLEX.
THUNDERSTORMS WILL DIMINISH THURSDAY AS THE LOW MOVES EAST. HIGH
PRESSURE AND DRIER AIR WILL START TO BUILD IN THURSDAY NIGHT.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
HIGH PRESSURE WILL BE BUILDING INTO THE REGION FRIDAY AND KEEP A
COOLER THAN NORMAL AIRMASS OVER US FRIDAY AND FRIDAY NIGHT. FLOW
WILL TURN BACK SOUTHERLY AND REMAIN THAT WAY THROUGH THE REMAINDER
OF THE PERIOD. IT WILL WARM UP DAYTIME HIGHS BACK INTO THE UPPER 70S
AND MORE NORMAL LOWER 80S. NIGHTTIME LOWS WILL RISE TO NORMAL
SATURDAY NIGHT AND THEN THE INCREASED MOISTURE WILL BUMP THAT INTO
THE MID AND UPPER 60S SUNDAY NIGHT UNTIL SHOWERS AND THUNDERSTORMS
COOL OFF THE REGION.
THE NEXT THREAT FOR RAIN WILL BEGIN ON SUNDAY BUT THIS APPEARS TO BE
A REACTION TO THE INCREASED MOISTURE STREAMING IN ON THE SOUTHERLY
FLOW. UPPER LEVEL MAN RIDGE IS STILL WEST OF THE REGION BUT APPEARS
FLATTENED AND MODELS ARE SHOWING IMPULSES RIDING EAST-SOUTHEAST
ALONG IT TO HELP KICK OFF STORMS ON SUNDAY...PARTICULARLY ALONG AND
NORTH OF I-70. BY THE TIME SUNDAY NIGHT AND MONDAY ROLLS IN...A MORE
ORGANIZED UPPER TROUGH WILL HAVE PUSHED THE MEAN RIDGE BACK TO THE
GULF STATES AND THUNDERSTORMS WILL BE MORE LIKELY WITH A FRONTAL
PASSAGE. ACTIVE WEATHER MAY OCCUR UNTIL THE FRONT FULLY CROSSES THE
REGION EARLY TUESDAY.
&&
.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
CONSIDERABLE UNCERTAINTY REGARDING DEVELOPMENT OF CONVECTION
THROUGHOUT THE TAF PERIOD. BUT OUTSIDE OF ANY STORMS EXPECT VFR
CONDITIONS TO PREVAIL.
THERE CONTINUE TO BE INDICATIONS THAT ELEVATED SHOWERS OR
THUNDERSTORMS MAY DEVELOP OVER THE NEXT SEVERAL HOURS. BUT
CONFIDENCE IS NOT TOO HIGH WITH THIS POTENTIAL. SO HAVE INCLUDED
VCSH FOR INITIAL ISSUANCE AND WILL CONTINUE TO MONITOR CLOSELY.
DURING THEY DAYTIME IT APPEARS MORE LIKELY THAT STORMS WILL BE
SUPPRESSED ALTHOUGH CANNOT COMPLETELY RULE OUT SOME ACTIVITY
ESPECIALLY IN CENTRAL OHIO LATE IN THE DAY. MUCH BETTER CHANCE OF
STORMS WILL COME LATE IN THE TAF PERIOD. WITH TIMING A QUESTION
ESPECIALLY THAT FAR OUT IN TIME HAVE ONLY GONE WITH VCTS. BETTER
CHANCE MAY COME JUST BEYOND THE TAF PERIOD. THESE STORMS WILL HAVE
THE POTENTIAL TO PRODUCE VERY STRONG STRAIGHT LINE WINDS.
OUTLOOK...THUNDERSTORMS EXPECTED LATE WEDNESDAY NIGHT INTO
THURSDAY MORNING. SOME OF THESE COULD CONTAIN STRONG WIND GUSTS.
MVFR CEILINGS LIKELY THURSDAY. ADDITIONAL THUNDERSTORMS POSSIBLE
SUNDAY.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...CONIGLIO
NEAR TERM...SITES
SHORT TERM...CONIGLIO
LONG TERM...FRANKS
AVIATION...
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
345 AM EDT WED JUN 12 2013
.SYNOPSIS...
A QUASI-STATIONARY FRONT WILL REMAIN DRAPED FROM THE NORTHWEST
CORNER OF THE STATE...TO SOUTH-CENTRAL PENNSYLVANIA TODAY. THIS
FRONTAL BOUNDARY WILL PIVOT SLIGHTLY TO A MORE EAST-WEST DIRECTION
TONIGHT. A POTENT STORM WILL RIDE ALONG THIS BOUNDARY...PASSING OVER
SOUTHERN OR CENTRAL PENNSYLVANIA ON THURSDAY. A COLD FRONT WILL DIVE
SOUTHEAST ACROSS THE REGION ON FRIDAY...FOLLOWED BY A LARGE HIGH
PRESSURE SYSTEM FOR SATURDAY.
&&
.NEAR TERM /UNTIL NOON TODAY/...
A NEARLY STATIONARY...AND VERY SHARP 925-850 MB THETA-E BOUNDARY WAS
LOCATED FROM KERI...SE TO KFKL...KAOO AND KHGR EARLY THIS MORNING.
A PULSE OF HIGHER PWAT AIR AND WESTERLY FLOW AROUND THE 850 MB LEVEL
IMPINGING ON THIS BOUNDARY WILL HELP TO FORM ONE OR MORE AREAS OF
SHOWERS THAT WILL SLIDE SEWRD /NEAR AND JUST TO THE EAST OF THE
BOUNDARY/ THIS MORNING. ONE OR TWO...COMPACT AND LOW-TOPPED TSRA
CAN/T BE RULED OUT ACROSS THE LAURELS THIS MORNING ON THE SW SIDE OF
THE BOUNDARY.
RAINFALL AMOUNTS WILL BE GENERALLY LIGHT AND LESS THAN ONE TENTH OF
AN INCH ACROSS THE CENTRAL AND WESTERN ZONES. HOWEVER...SHORT
RANGE/HIGH RES NAM AND HRRR GUIDANCE IMPLIES THAT A FEW LOCATIONS
COULD RECEIVE SLIGHTLY HIGHER AMOUNTS THROUGH 15Z.
THE HIGHER PWAT AIR AND LLVL BOUNDARY IS BRIEFLY SHUNTED A BIT TO
THE SOUTHWEST THIS AFTERNOON...THANKS TO VERTICAL MIXING OF MUCH
DRIER AIR ALOFT AHEAD OF WEAK RIDGING THAT WILL BE SLIDING EAST OVER
THE REGION.
LOW TEMPS AROUND DAYBREAK TODAY WILL RANGE FROM THE MID 50S OVER THE
NORTH TO AROUND 60 IN THE SOUTH.
&&
.SHORT TERM /NOON TODAY THROUGH 6 PM THURSDAY/...
QUASI-STATIONARY FRONT STAYS HUNG UP OVER SWRN PA THROUGH TODAY.
DESPITE LACK OF SIG LG SCALE FORCING ON WED...DIURNAL HEATING
COMBINED LIFT ALONG STATIONARY FRONT SHOULD SUPPORT SCT AFTN/EVENING
SHOWERS AND THUNDERSTORMS OVER MY SW COUNTIES.
EXPECT SKIES TO STAY MOSTLY CLOUDY FOR MUCH OF TODAY WITH VARYING
AMOUNTS OF HIGH-BASED STRATO CU AND ALTO CU STREAMING SEWRD ACROSS
THE STATE.
SPC HAS TRANSITIONED FROM THEIR DAY 2 TO DAY 1 SLIGHT /AND MDT/ RISK
AREAS OVER THE SW HALF OF PENN...OUT THROUGH THE OHIO VALLEY -
VIRTUALLY UNCHANGED.
THINKING IS THAT THE PRIMARY RISK FOR OUR REGION WILL BE ASSOCIATED
WILL LATER DEVELOPMENTS OVER THE MIDWEST THAT COULD MOVE IN TONIGHT
AND EARLY THURSDAY...SO FOR RIGHT NOW THIS AFTERNOON AND EVENING
DOESN/T LOOK TERRIBLY THREATENING OVERALL...AS THE BEST INSTABILITY
SOUTH AND WEST OF OUR AREA OF CONCERN THROUGH MOST OF THIS TIME
FRAME.
ALTHOUGH CLOUDS MAY PREDOMINATE TODAY...BREAKS OF SUN AND LOW
CHANCES FOR PRECIP DURING THE LATE MORNING AND AFTERNOON HOURS
SHOULD ALLOW TEMPS TO RECOVER TO NEAR NORMAL OVR THE NORTH AND
LIKELY A BIT ABV NORMAL IN THE SOUTH...WHERE ENS MEAN 8H TEMPS GET
CLOSE TO 15C. MUCH HIGHER PWAT AIR WILL BEGIN IT/S BIG SURGE NE
ACROSS THE FCST AREA VERY LATE TODAY AND TONIGHT.
ABNORMALLY STRONG DYNAMICS WILL SUPPORT A DEEP LOW MOVING ACROSS
SCENT PA ON THU.
POTENT UPPER SHORT WAVE ACCOMPANIED BY A STRONG WSWRLY LLJ /AND THE
SUB-1000MB SFC LOW/ WILL IMPACT ALL OF THE REGION THURSDAY WITH A
WIDE RANGE OF TEMPERATURES AND WEATHER.
LATEST...00Z/03Z OPERATIONAL MODELS AND THEIR RESPECTIVE ENSEMBLES
REMAIN IN VERY GOOD AGREEMENT TRACKING AN ANOMALOUSLY STRONG 990-995
MB SFC LOW ACROSS CENTRAL OR SOUTHERN PENN DURING THE DAY THURSDAY.
DEEP UVVEL BENEATH THE THERMALLY DIRECT BRANCH OF AN UPPER JET
LOCATED ACROSS NEW YORK AND SRN NEW ENGLAND WILL AID IN STRONG
ASCENT OF THE HIGH PWAT AIR /1.5-2 INCHES/ OVER THE QUASI STNRY OR
SFC WARM FRONT /EXPECTED TO BE SITUATED FROM WCENT PENN TO THE SCENT
MTNS AND LOWER SUSQ VALLEY/. THESE FACTORS WILL COMBINE TO PRODUCE A
WIDESPREAD...SOAKING RAINFALL OF 1-2 INCHES ACROSS THE NORTHERN HALF
OF THE STATE. 24 SREF PROB FOR 2 INCH OR GREATER RAINFALL IS 40-50
PERCENT ACROSS THE NORTHERN 1/2 OF PENN...WHILE ITS 24 HR
PROBABILITY FOR OVER 1 INCH OF QPF IS 60-80 PERCENT STATE-WIDE.
ACROSS THE SOUTH...IN THE MUCH WARMER AND MORE HUMID AIR /ESP NEAR
AND TO THE SOUTH OF THE PENN TURNPIKE/...SIGNIFICANT BREAKS IN THE
CLOUD COVER MAY DEVELOP HELPING TO RAMP UP MUCAPES TO BETWEEN
2000-3000 J/KG IN THE AFTERNOON. THIS CONVECTIVE ENERGY WILL BE NEAR
THE NORTHERN EDGE OF THE MOST ANOMALOUS /PLUS 3 SIGMA/ WSW 850 MB
FLOW.
A RATHER BROAD AREA OF UNUSUALLY HIGH...0-1KM EHI FOR THIS AREA /OF
AROUND 2-3M2/S2/ IS FCST TO DEVELOP NEAR AND JUST SOUTH OF THE
SLOW-MOVING WARM FRONTAL BOUNDARY TO POSE A THREAT FOR BOWING LINE
SEGMENTS WITH SCATTERED SUPERCELLS/ISOLATED TORNADOES POSSIBLE FROM
THE LATE MORNING THROUGH THE AFTERNOON HOURS. SPC HAS COVERED
ROUGHLY THE SERN HALF OF PENN WITH THEIR DAY 2 SLIGHT RISK
AREA...WHILE THE FAR SERN ZONES ARE AT THE NW EDGE OF A MDT RISK
/WHICH EXTENDS SOUTH THROUGH THE I-95...MID ATLANTIC CORRIDOR/.
A RIBBON OF VERY IMPRESSIVE /AND NOT OFTEN SEEN IN THIS AREA/ 0-1KM
EHIS OF 4M2/S2 OR GREATER DEVELOP ACROSS THE LOWER SUSQ WHERE THE
MID-LATE AFTERNOON TIMING OF THE BEST INSTABILITY AND LLVL SHEAR
WILL OCCUR INVOF OF THE THE SHARP STNRY FRONT /OR SLOWLY MOVING WARM
FRONTAL BOUNDARY/. SIGNIF PERCENTAGE OF THE STORMS IN THE LOWER SUSQ
COULD CONTAIN MDT TO STRONG MESOS FOR UP TO SVRL HOURS THURSDAY
AFTERNOON AND EVENING INVOF KTHV...KMDT AND KLNS WITH AN ENHANCED
THREAT FOR A FEW TORNADOES IN THAT AREA. LOW LCL HEIGHTS AND THE
VERY STRONG SOUTH-SWRLY 0-1KM SHEAR NEAR AND JUST TO THE NORTH OF
THE BOUNDARY WILL CREATE THE GREATEST THREAT FOR THE SUPERCELLS WITH
POSSIBLE LARGE HAIL IN THE 17Z-22Z PERIOD ACROSS THE LOWER SUSQ
VALLEY.
AS HIGHLIGHTED LAST NIGHT...THE NORTH-SOUTH SFC TEMP GRADIENT
THURSDAY AFTERNOON SHOULD TURN OUT TO BE QUITE SHARP...ESPECIALLY IF
SIGNIFICANT BREAKS FORM ACROSS THE SOUTH.
EARLIER WENT ALL IN BY RAISING POPS TO 100 PERCENT FOR THE ENTIRE
AREA THURSDAY...AND THIS LOOKS TO BE A WISE MOVE BASED ON THE SHORT
RANGE OPERATIONAL AND ENSEMBLE MODEL CONSENSUS OF WIDESPREAD HEAVY
RAIN AND CONVECTION.
WILL MAINTAIN TEMPS BELOW GUIDANCE...GIVEN CLDS AND SOAKING RAIN
BENEATH THE WELL DEFINED...THERMALLY DIRECT BRANCH OF A STRONG UPPER
LEVEL JET. THE SECOND CONCERN IS HEAVY RAIN...AND POTENTIAL FOR
LOCALIZED FLASH FLOODING/FLOODING OF STREAMS AND CREEKS.
24-30 HOUR...STORM TOTAL QPF RANGES FROM 2-2.5 INCHES ACROSS MUCH OF
NRN PENN...TO SLIGHTLY UNDER ONE INCH IN THE FAR SE.
MARFC IS IN THE 2 TO 3 INCH RANGE FOR STORM TOTAL QPF. MOST PLACES
SHOULD BE ABLE TO HANDLE THIS AMT OF RAIN OVER A 12-24 HOUR PERIOD.
HOWEVER...IF MUCH OF THIS COMES DOWN IN JUST A 3-6 HOUR
PERIOD...SIGNIFICANT PROBLEMS COULD DEVELOP QUICKLY IN TYPICALLY
FLOOD PRONE AREAS.
COORDINATED WITH SURROUNDING WFOS TO HOLD OFF ON A FLASH FLOOD WATCH
AT THIS POINT...ESP SINCE THE BULK OF THE RAIN IS STILL CONFINED TO
THE 3RD PERIOD OF THE FCST...AND FFG FOR OUR CWA IS SOME OF THE
HIGHEST OBSERVED IN THE ENTIRE MID-ATLANTIC REGION /2.25 - 3 INCHES
PER 12 HOURS OVER OUR ENTIRE CWA/. AREAS TO THE WEST AND EAST OF OUR
FCST AREA NEED SIGNIFICANTLY LOWER AMOUNTS OF RAIN TO CAUSE FLOODING
PROBLEMS...ESPECIALLY OVER TO OUR EAST.
&&
.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
DID LOWER TEMPS ON FRIDAY BY 2 TO 5 DEGREES...COMBINATION OF
SECONDARY COLD FRONT DROPPING SOUTHWARD FROM SOUTHERN
ONTARIO...AND DEEP LOW MOVING OFF THE COAST WILL SUPPORT MORE COLD
ADVECTION AND ALSO SOME SHOWERS FRIDAY MORNING.
IMPROVING CONDITIONS FOR SAT.
WENT WITH A LOW CHC FOR SHOWERS AND STORMS ON SUNDAY...GIVEN
WARM ADVECTION.
CHC OF MORE SHOWERS AND STORMS ON MONDAY AND TUE...AS THE WARM
FRONT MOVES NE ON MONDAY...FOLLOWED BY A COLD FRONT ON TUE.
&&
.AVIATION /07Z WEDNESDAY THROUGH SUNDAY/...
A QUASI-STATIONARY FRONTAL BOUNDARY WILL REMAIN DRAPED NW-SE ACROSS
WESTERN PENNSYLVANIA TONIGHT INTO WEDNESDAY. A POTENT STORM WILL
RIDE ALONG THIS BOUNDARY LATE WED NIGHT THROUGH THU NIGHT.
EARLY THIS MORNING...VFR PREVAILING AT ALL TAF SITES EXCEPT BFD.
PROXIMITY TO THE FRONTAL BOUNDARY WILL KEEP KBFD IFR/MVFR IN
SHOWERS THROUGH SUNRISE. THE AREA OF MVFR CIGS WILL EXPAND SOUTH
AND EAST INTO THE LAURELS AND CENTRAL MTNS LATER TONIGHT /AFT
09Z/ AS A FAIR AMOUNT OF LOW LEVEL MOISTURE REMAINS TRAPPED UNDER
INVERSION...WITH SHOWERS POSS NEAR KJST TOWARD SUNRISE. LIGHT FOG
POSS IN THE SUSQ VALLEY.
ON WED...LOWER CIGS IN THE NW HALF WILL STUBBORNLY PERSIST FOR
MUCH OF THE MORNING...THEN SLOWLY IMPROVE TO VFR AS LOWER LAYER
MIXES AND HIGH PRESSURE SLIDES ACROSS NY STATE. FRONTAL BOUNDARY
SLIPS SOUTHWARD TO NEAR KJST-KAOO. DESPITE LACK OF SIG LARGE
SCALE FORCING...DIURNAL HEATING COMBINED WITH LIFT ALONG
STATIONARY FRONT SHOULD SUPPORT SCT AFTN/EVENING TSTMS NEAR KJST-
KAOO.
THEN FOCUS TURNS TO POTENT LOW PRESSURE SYSTEM APPROACHING FROM
THE MIDWEST...WITH IMPACTS BEGINNING WED NIGHT. LARGE AREA OF
PRECIP OVERSPREADS REGION FROM THE WEST AS NIGHT PROGRESSES.
MODELS INDICATING THAT CIGS REMAIN PRIMARILY VFR EXCEPT ACROSS
THE WEST...WHERE RESTRICTIONS WILL DEVELOP. RAIN CONTINUES THROUGH
THURSDAY NIGHT...WITH POTENTIAL FOR LARGE IMPACTS FROM STRONG
THUNDERSTORMS AND WIND SHEAR THU AFT INTO THU EVE.
OUTLOOK...
WED NIGHT-THU MORN...RAIN AND SCT TSTMS BECOMING MORE WIDESPREAD.
REDUCTIONS DEVELOPING...MAINLY WEST.
THU AFT-THU NIGHT...LARGE IMPACTS FROM STRONG TSTMS AND WIND SHEAR
LIKELY. OTHERWISE SHOWERS CONTINUE. REDUCTIONS ALL AREAS THU AFT-
EVE...THEN WIDESPREAD REDUCTIONS NW HALF THU NIGHT.
FRI...CHANCE OF SHOWERS...MAINLY EARLY. PRIMARILY VFR CONDITIONS.
SAT...NO SIG WX.
SUN...NO SIG WX. ISO TSTMS LATE.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...LAMBERT
NEAR TERM...LAMBERT
SHORT TERM...LAMBERT
LONG TERM...MARTIN
AVIATION...RXR
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
157 AM EDT WED JUN 12 2013
.SYNOPSIS...
WARM HIGH PRESSURE WILL BUILD ACROSS THE REGION WEDNESDAY BEFORE A
COLD FRONT AFFECTS THE AREA ON THURSDAY. DRY HIGH PRESSURE WILL
BUILD IN FROM THE NORTH FRIDAY AND SATURDAY AND KEEP THE WEATHER DRY
OVER MOST OF THE THE WEEKEND. ANOTHER COLD FRONT WILL APPROACH THE
REGION EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH TODAY/...
AS OF THE EARLY MORNING HOURS...ALL IS QUIET. NOTHING GOING ON
UPSTREAM TO SPEAK OF. NO BIG CHANGES.
PREVIOUS DISCUSSION...
AS OF 1030 PM EDT...RADARS REMAIN FAIRLY QUIET UPSTREAM IN THE WEAK
MCS GENESIS REGION ACROSS THE OH VALLEY. HOWEVER...BOTH THE INCOMING
00Z NAM AND THE LATEST HRRR RUN INDICATE CONVECTIVE DEVELOPMENT OVER
SRN OH CIRCA 08Z TO 09Z...AND THIS ACTIVITY COULD WELL MAKE A RUN TO
THE SPINE OF THE SRN APPALACHIANS BEFORE 12Z. WILL THUS CONTINUE TO
FEATURE LOW END CHC POPS ALONG THE TN BORDER STARTING AROUND
DAYBREAK...WITH SCT COVERAGE POSSIBLY SURVIVING INTO THE FOOTHILLS
THROUGH LATE WED MORNING. MODEL PROFILES STILL EXHIBIT QUITE A BIT
OF LOW LEVEL CIN EAST OF THE MTNS...SO WILL KEEP POPS CAPPED AT
SLIGHT CHANCE FOR THE SE HALF THROUGH WED.
LOW LEVEL THICKNESSES SUPPORT MAX TEMPS IN THE MID 90S OVER MUCH OF
THE PIEDMONT WED AFTN. HOWEVER...EXPECT THAT SOME DEBRIS CLOUDS WILL
BE AROUND THROUGH AT LEAST MIDDAY WHICH WILL SLOW DOWN THE WARMING.
EVEN SO...A GUIDANCE BLEND SUPORTS MAX TEMPS IN THE LOW 90S OVER
MUCH OF THE PIEDMONT...WITH MID 80S IN THE MOUNTAIN VALLEYS.
&&
.SHORT TERM /TONIGHT THROUGH FRIDAY/...
AS OF 245 PM TUESDAY...SHORT RANGE MODELS AGREE THAT THE CENTER OF SFC
LOW PRESSURE WILL TRACK NE ACROSS THE NORTHERN OHIO RIVER VALLEY BY
12Z THURSDAY. AT H5...THE AXIS OF MID LEVEL TROF IS EXPECTED TO
RIPPLE FROM THE OHIO RIVER VALLEY ACROSS THE NC MTNS BY 21Z THURS.
AT THE SFC...A COLD FRONT ASSOCIATED WITH THE NRN LOW PRESSURE WILL
SWEEP ACROSS THE NC MTNS DURING THE EARLY AFTERNOON. THE TIMING OF
THE SFC FRONT AND MID LEVEL WAVE WILL FALL DURING PRIME DIURNAL TIME
FOR DEEP CONVECTION. NAM FORECAST SOUNDINGS ACROSS THE FOOTHILLS AND
PIEDMONT INDICATE THAT CAPE VALUES WILL EXCEED 2000 J/KG...EHI
BETWEEN.5 TO 1 M2/S2...SWEAT GREATER THAN 350. A WEAK BAND OF MAINLY
PRE FRONTAL SHRA MAY REACH THE NC MTNS DURING THE MORNING.
HOWEVER...AS THE LINE MOVE EAST ACROSS THE FOOTHILLS AND
PIEDMONT...CONDITIONS WILL BECOME MORE SUPPORTIVE FOR TSRA
ORGANIZATION INTO A QLCS. THE PRIMARY THREATS WITH THE QLCS WILL BE
DAMAGING STRAIGHT-LINE WINDS AND HAIL...ESPECIALLY ACROSS THE I-77
CORRIDOR. WE WILL CONTINUE TO HIGHLIGHT THE SVR WEATHER THREAT IN
THE HWO.
HIGH TEMPERATURE GUIDANCE ON THURSDAY REMAINS DIVIDED FROM THE VERY
WARM MAV...UPPER 90S...TO THE MET...LOWER TO MID 90S. GIVEN THE
PATTERN OF FALLING LOWER THE MID HEIGHTS...I WILL FAVOR THE MET.
FRIDAY...SHOULD VERIFY AS A FAIR WEATHER DAY AS CANADIAN HIGH
PRESSURE BUILD SOUTH ACROSS THE REGION IN THE WAKE OF THE COLD
FRONT. I WILL FORECAST DRY CONDITIONS WITH LIGHT NORTHEAST WINDS.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
AS OF 115 PM TUESDAY...NO MAJOR CHANGES NEEDED TO THE GOING FCST.
THE MODELS AGREE WELL WITH A BUILDING RIDGE AND LARGE AREA OF DEEP
SUBSIDENCE CONTROLLING THE WX THROUGHOUT THE WEEKEND. AT THE SFC...A
CP HIGH WILL MOVE SOUTH OVER THE REGION SAT/SUN...AND ALONG WITH
RELATIVELY WARM MLVLS...DRY CONDS WITH NEAR SEASONAL TEMPS ARE
EXPECTED. THERE IS SOME DIFFERENCES WRT THE MAGNITUDE AND CHARACTER
OF THE NEXT S/W DEVELOPING OVER THE MIDWEST MON...HOWEVER WILL COUNT
ON A GENERAL INCREASE IN DYNAMICS ALOFT AND HIGHER LLVL MOISTURE
FLUX THROUGH NEW DAY 7. MODEL SOUNDINGS ARE SHOWING GOOD SBSAPE AND
ELCAPE POTENTIAL WITH SOME MODERATE BULK SHEAR...SO THE ENVIRONMENT
WILL BE SET FOR STRONG TO SEVERE CONVECTION DEVELOPING EACH
AFTERNOON MON THROUGH THE PERIOD. MAX TEMPS SHOULD BUMP A COUPLE
DEGREES EACH DAY ONCE SW/LY FLOW BECOMES MAINTAINED SUN NIGHT.
&&
.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
AT KCLT...VFR THROUGH THE FORECAST PERIOD...WITH A CAVEAT. EXPECT
ONLY HIGH CLOUDS WITH A NEARLY CALM WIND THROUGH DAYBREAK. NOT GOING
TO RULE OUT SOME BRIEF GROUND FOG AT DAYBREAK GIVEN THE RECENT
WETNESS. THROUGH THE DAY...THE FCST SOUNDINGS FROM MOST MODELS ARE
CAPPED...SO ONLY A FEW SCRAGGILY HIGH BASED STRATOCU ARE EXPECTED
THROUGH MOST OF THE AFTERNOON...UNDERNEATH SOME MID AND HIGH LEVEL
CONVECTIVE DEBRIS MOVING DOWN FROM THE NW. WIND SHOULD COME AROUND
TO WSW BECAUSE OF A LEE TROF DURING THE AFTERNOON. AND NOW HERE IS
THE CAVEAT...SOME OF THE CONVECTION ALLOWING MODELS SUGGEST A
COMPLEX OF THUNDERSTORMS WILL DEVELOP OVER SRN WV THIS AFTERNOON AND
THEN PLOW SOUTHWARD ACROSS THE PIEDMONT OF NC IN THE AFTERNOON...
PERHAPS WITH DECENT POTENTIAL FOR DAMAGING WIND GUSTS AND LARGE
HAIL. IN THAT CASE...THE CAP WOULD WORK TO THE ADVANTAGE OF THE
STORMS BY HOLDING THE LID ON THE DEEP CONVECTION AND STORING UP ALL
THE ENERGY UNTIL THE SQUALL LINE ARRIVES TO RELEASE IT. THIS IS ALL
CONJECTURE. THE FCST REFLECTS THE MOST LIKELY SCENARIO...WHICH IS
FOR NOTHING TO HAPPEN OTHER THAN ISOLATED EARLY EVENING STORMS.
HOWEVER...THE OTHER SCENARIO IS WITHIN THE REALM OF POSSIBILITIES SO
KEEP IT IN THE BACK OF YOUR MIND. EITHER WAY...THE EVENING SHOULD
BECOME UNEVENTFUL WITH LIGHT WIND AFTER SUNSET.
ELSEWHERE...EXPECT MAINLY INCREASING HIGH LEVEL CLOUDS FROM MCS
DEBRIS ARRIVING FROM THE NW THROUGH DAYBREAK. THERE COULD BE SOME
MVFR VISIBILITY IN THE VICINITY OF KAVL AROUND SUNRISE. FOR THIS
AFTERNOON...SCENARIO IS SIMILAR TO KCLT E OF THE BLUE RIDGE...WITH
ISOLATED THUNDERSTORMS POSSIBLE...BUT WILL NOT MENTION AT THIS TIME.
OUTLOOK...A COLD FRONT WILL BRING A GOOD CHANCE OF SHOWERS AND
THUNDERSTORMS TO THE REGION ON THURSDAY. HIGH PRESSURE WILL BUILD IN
BEHIND THE FRONT AND PRODUCE GENERALLY QUIET WEATHER AND VFR
CONDITIONS THROUGH THE WEEKEND.
CONFIDENCE TABLE...
06-12Z 12-18Z 18-24Z 00-06Z
KCLT HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KGSP HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAVL HIGH 94% HIGH 94% HIGH 100% HIGH 100%
KHKY HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KGMU HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAND HIGH 100% HIGH 100% 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...GOODMAN
NEAR TERM...HG/PAT
SHORT TERM...NED
LONG TERM...SBK
AVIATION...PM
AREA FORECAST DISCUSSION...UPDATED
NWS ABERDEEN SD
1224 AM CDT WED JUN 12 2013
.UPDATE...
AVIATION DISCUSSION HAS BEEN UPDATED FOR 06Z TAFS.
A LOT OF LOW LEVEL DRY AIR HAS FILTERED INTO THE CWA THIS EVENING
AS SURFACE DEW POINTS HAVE DROPPED AT ALL LOCATIONS. STRONG
CAPPING ALONG WITH 1000 TO 1500 J/KG OR MORE OF MUCAPE EXISTS ACROSS
THE CWA THIS EVENING. WITH THE LARGE SCALE ASCENT AND WAA WITH THE
APPROACHING SHORT WAVE TROUGH...THUNDERSTORMS WERE DEVELOPING AND
INCREASING IN COVERAGE ACROSS EASTERN WY INTO NORTHWEST NEBRASKA
THIS EVENING. EXPECT THIS TREND TO CONTINUE OVER THE NEXT SEVERAL
HOURS AS EVERYTHING HEADS OFF TO THE NORTHEAST. EXPECT CONVECTION
TO STILL LINE OUT AS IT MOVES EAST ACROSS SOUTHERN SD TONIGHT AND
MAY BE SEVERE AS 0-3KM SHEAR REMAINS STRONG. WINDS WILL BE THE
MAIN THREAT. AREAS ALONG AND SOUTH OF I-90 HAVE THE BEST CHANCE OF
SEVERE. THE LATEST HRRR RUN WAS SHOWING MORE NUMEROUS SHOWERS AND
STORMS DEVELOPING OVER THE REGION THROUGH THE NIGHT WITH NOT MUCH
OF A LINE ACROSS THE SOUTH. WILL HAVE TO WAIT AND SEE. ALREADY
HAVE IN GOOD CHANCES OF RAINFALL ACROSS MUCH OF THE CWA TONIGHT.
&&
.PREVIOUS DISCUSSION...
.SHORT TERM...TONIGHT THROUGH THURSDAY NIGHT
THE CHANCE FOR SEVERE WEATHER TONIGHT IS THE MAIN FORECAST
CHALLENGE. AN UPPER LEVEL SHORTWAVE WILL RIDE OVER THE TOP OF A
RIDGE CURRENTLY OVER THE PLAINS AND ACROSS THE STATE TONIGHT INTO
WEDNESDAY. A SURFACE LOW PRESSURE SYSTEM WILL TRACK ACROSS
NEBRASKA TONIGHT...WITH MOISTURE WRAPPING AROUND IT TO THE NORTH
ACROSS SOUTH DAKOTA. THE BEST INSTABILITY LOOKS TO BE OVER THE
SOUTHERN PART OF THE STATE AND ACROSS NEBRASKA. 0-6 KM BULK SHEAR
VALUES IN EXCESS OF 50 KTS DEVELOP ACROSS SOUTHERN SOUTH DAKOTA AS
WELL. LOOKING AS THOUGH STORMS WILL DEVELOP ACROSS EASTERN WYOMING
AND WESTERN SOUTH DAKOTA DURING THE EVENING HOURS...THEN TRACK
EASTWARD THROUGH THE NIGHT AND INTO EARLY WEDNESDAY. AGAIN...THE
MAIN FOCUS FOR SEVERE WEATHER WILL BE ACROSS THE SOUTHERN HALF OF
THE STATE WHERE THE SET UP WILL BE BETTER FOR HAIL AND STRONG
WINDS. MAY SEE A BOWING FEATURE AFFECT PARTS OF THE FAR SOUTHERN
CWA...MAINLY SOUTH OF INTERSTATE 90 IN THE 03Z-09Z TIME FRAME.
AFTER SOME LINGERING PRECIPITATION WEDNESDAY MORNING...HIGH
PRESSURE DROPS OVER THE REGION AND LOOKS TO KEEP THINGS DRY
THROUGH THE DAY THURSDAY. SOME DISAGREEMENT IN THE MODELS WITH
THURSDAY NIGHT AS THE GFS AND THE NAM INDICATE PRECIPITATION
DEVELOPING AHEAD OF AN APPROACHING LOW PRESSURE SYSTEM...WHILE THE
ECMWF KEEPS THINGS DRY. WILL GO AHEAD AND KEEP A SMALL POP TO
ACCOUNT FOR THE DIFFERENCES.
NEAR TO SLIGHTLY ABOVE NORMAL TEMPERATURES WILL CONTINUE DURING
THE SHORT TERM...WITH HIGHS MAINLY IN THE MID TO UPPER 70S BOTH
WEDNESDAY AND THURSDAY.
.LONG TERM...FRIDAY THROUGH TUESDAY
THE PERIOD STARTS WITH UPPER LEVEL RIDGING OVERHEAD AND A TROUGH
WORKING ITS WAY INTO THE NORTHERN ROCKIES. THE ASSOCIATED SURFACE
LOW WILL ALSO MOVE INTO THE PLAINS STATES FRIDAY...AND THERE SHOULD
BE SOME MOISTURE RETURN...WITH MODEL BOUNDARY LAYER DEWPOINTS
RISING BACK INTO THE UPPER 50S TO LOW 60S. MODELS ARE NOT SHOWING
ANY REAL SIGNIFICANT WAVES OF ENERGY KICKING OUT AHEAD OF THE
TROUGH AND RIDING OVER THE RIDGE ON FRIDAY...AND THE MOST
SIGNIFICANT 500 MB HEIGHT FALLS DO NOT OCCUR UNTIL LATE FRIDAY
INTO SATURDAY. SO AT THIS TIME IT LOOKS LIKE THE BEST
PRECIPITATION CHANCES WILL OCCUR WITH THE COLD FRONTAL PASSAGE
EARLY SATURDAY MORNING. A PROGRESSIVE PATTERN REMAINS IN PLACE
THROUGH THE REMAINDER OF THE PERIOD...WITH SEVERAL SHORTWAVES
MOVING THROUGH NORTHWEST FLOW. OF COURSE...TIMING AND INTENSITY OF
THESE WAVES DIFFERS BETWEEN MODELS...SO DID NOT MODIFY THE
ALLBLEND SOLUTIONS THROUGH THE END OF THE LONG TERM PERIOD.
OVERALL TEMPERATURES APPEAR TO BE RIGHT AROUND...TO EVEN SLIGHTLY
ABOVE NORMAL THROUGH THE LONG TERM PERIOD.
&&
.AVIATION...
06Z TAFS FOR THE KABR...KATY...KPIR AND KMBG TERMINALS
AN UPPER LEVEL LOW PRESSURE TROUGH WILL TRAVERSE OVER THE REGION
TONIGHT AND EARLY WEDNESDAY BRINGING SCATTERED TO NUMEROUS
SHOWERS AND THUNDERSTORMS. WITH GOOD COVERAGE EXPECTED...INSERTED
SHOWERS AND VICINITY THUNDER AT ALL TERMINALS. THIS WAVE OF
PRECIPITATION WILL MOVE BY ON WEDNESDAY MORNING. EXPECT CEILINGS
TO BE VFR THROUGH THE ENTIRE TAF PERIOD WITH MAYBE SOME REDUCTION
IN VISIBILITY WITH ANY RAINFALL. WILL WATCH FOR ANY THUNDER
EXPECTED AT ANY STATION. SURFACE HIGH PRESSURE WILL BUILD IN
WEDNESDAY AFTERNOON AND EVENING. SKIES WILL CLEAR WEDNESDAY
EVENING WITH WINDS BECOMING LIGHT.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
&&
$$
UPDATE...MOHR
SHORT TERM...PARKIN
LONG TERM...SERR
AVIATION...TDK
WEATHER.GOV/ABERDEEN
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
318 AM CDT WED JUN 12 2013
.SHORT TERM...(TODAY THROUGH THURSDAY)
ISSUED AT 318 AM CDT WED JUN 12 2013
MAIN CONCERN FOR TODAY INTO THIS EARLY EVENING WILL BE SEVERE
THUNDERSTORM THREAT ACROSS THE SOUTH.
WATER VAPOR IMAGERY/RAP 500MB HEIGHT FIELD SHOWS A VIGOROUS
SHORTWAVE TROUGH MOVING OUT OF MT/WY INTO WESTERN ND/SD/NE. SURFACE
MAP AS OF 2 AM HAD AN AREA OF LOW PRESSURE ALONG THE KS/NE BORDER
WITH A WARM FRONT EXTENDING ENE ALONG I-80 IN IA AND IL. 850MB
MOISTURE TRANSPORT/ISENTROPIC LIFT AHEAD OF THE LOW AND OVER THE
WARM FRONT WAS PRODUCING SCATTERED ELEVATED SHRA/TS ACROSS OUR
FORECAST AREA...WITH A MORE INVIGORATED N-S LINE OF STORMS ACROSS
CENTRAL SD WHICH WAS HEADED EAST AROUND 50KT. RAP CORFIDI VECTORS
TAKE THIS COMPLEX OF STORMS DUE EAST AT 55-65KT THIS MORNING...WHICH
WOULD BRING IT INTO OUR AREA IN THE 7-9 AM TIME FRAME. MEANWHILE...A
NEW COMPLEX OF THUNDERSTORMS WERE FIRING ACROSS NORTHWEST
IA...MOVING TOWARD THE EAST. THIS CONVECTION WAS ROOTED A BIT CLOSER
TO THE CAPE POOL JUST NORTH OF THE 925-850MB WARM FRONT. A COUPLE
OBS IN SD WHERE THIS LINE PASSED RECORDED 43/48KT. HOWEVER...WRF
MODELS...NAMELY THE 12.00Z NSSL WRF WHICH SEEMS TO HAVE THE BEST
HANDLE ON THE CONVECTION RIGHT NOW...HAS THIS CONVECTION DECAYING AS
IT MOVES INTO THE AREA IN THE 5-8AM TIME FRAME. WITH 0-3KM BULK
SHEAR IN THE 40-50KT RANGE AND 0-3KM ML MUCAPE HOVERING IN THE
1000-2000J/KG...WILL HAVE TO WATCH THIS ONGOING CONVECTION CAREFULLY
FOR A SEVERE WIND THREAT EARLY THIS MORNING.
THERE THEN SEEMS TO BE A BREAK IN THE ACTION FROM MID-MORNING UNTIL
EARLY AFTERNOON BEFORE THE MID-LEVEL TROUGH AND SURFACE LOW MOVE
ACROSS EASTERN IA IN THE 18Z-21Z TIME FRAME. THIS TROUGH/STEEPENING
MID LEVEL LAPSE RATES THEN INTERACTS WITH 2000-3500J/KG 0-1KM ML
MUCAPE POOL IN PLACE SOUTH OF I-90 TO FIRE VIGOROUS/DEEP
CONVECTION. COOLING MID LEVEL/STEEPER LAPSE RATES AND 0-3KM BULK
SHEAR IN THE 20-40KT RANGE WILL SUPPORT A SEVERE HAIL/WIND THREAT
SOUTH OF I-90. AND...WITH THE JUXTAPOSITION OF THE LOW/WARM FRONT
PRODUCING FAVORABLE 0-3KM SRH...CANNOT RULE OUT A TORNADIC THREAT
ACROSS PORTIONS OF NORTHEAST IA INTO FAR SOUTHWEST WI...NAMELY
FAYETTE AND CLAYTON COUNTIES IN NORTHEAST IA AND GRANT COUNTY IN WI.
LOCALIZED FLOODING IS ALSO A CONCERN WITH THIS CONVECTION AS
PRECIPITABLE WATER VALUES HOVER IN THE 1.5 TO 2 INCH RANGE. SEE
HYDROLOGY SECTION BELOW FOR FURTHER DETAILS ON HEAVY RAIN POTENTIAL
AND IMPACTS. PLAN ON THE LOW AND ASSOCIATED CONVECTION TO MOVE
SOUTHEAST OF THE REGION AROUND MIDNIGHT TONIGHT. HIGH PRESSURE THEN
STARTS NOSING IN AFTER MIDNIGHT FROM THE NORTHERN PLAINS FOR
CLEARING SKIES.
HIGH PRESSURE WILL BE IN CONTROL ON THURSDAY WITH PLEASANT
TEMPERATURES IN THE 70S AND LOWER HUMIDITY LEVELS.
.LONG TERM...(THURSDAY NIGHT THROUGH TUESDAY)
ISSUED AT 318 AM CDT WED JUN 12 2013
HIGH PRESSURE REMAINS IN CONTROL ACROSS THE AREA THURSDAY NIGHT
THROUGH FRIDAY MORNING FOR A CONTINUED DRY RESPITE. BY FRIDAY
AFTERNOON THOUGH...A TROUGH OF LOW PRESSURE OVER THE PLAINS BEGINS TO
SHOVE MOISTURE BACK INTO THE AREA...MAINLY WEST OF THE MISSISSIPPI
RIVER FOR A CHANCE OF SHOWERS/ISOLATED THUNDER. FOR FRIDAY NIGHT
THROUGH SATURDAY EVENING...LOOK FOR LOW PRESSURE OVER CANADA TO SEND
A COLD FRONT THROUGH THE AREA. THIS WILL PRODUCE THE LIKELIHOOD OF
SHOWERS AND THUNDERSTORMS. WILL NEED TO WATCH FOR THE POSSIBILITY OF
SEVERE WEATHER GIVEN 0-1KM ML MUCAPE IN THE 1500-3500J/KG AND MODEST
AMOUNT OF 0-3KM BULK SHEAR. LINGERING MID-LEVEL TROUGH/FAIRLY STEEP
LAPSE RATES ENOUGH TO WARRANT A LOWER-END SHRA/TS CHANCE SUNDAY
THROUGH MONDAY. NORTHWEST FLOW AND ANOTHER WEAK MID-LEVEL TROUGH IN
THIS FLOW PRODUCE ANOTHER SHRA/TS CHANCE ON TUESDAY. OTHERWISE...
LOOKS LIKE TEMPERATURES WILL BE RIGHT AROUND NORMAL THROUGH THE
PERIOD...MAINLY IN THE 70S.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT) ISSUED AT
1105 PM CDT TUE JUN 11 2013
BANDS OF SHRA/TS FIRING ALONG LINES OF CONVERGENCE...MOSTLY WELL
ELEVATED WITH CIGS 10 KFT. SOME CHANGES IN THE MESO MODELS WITH HOW
THEY HANDLE LARGE THUNDERSTORM COMPLEXES EXPECTED TO DEVELOP OVER
THE NEXT FEW HOURS. ENOUGH CONSENSUS THAT WILL LEAN THE TAFS TOWARD
THESE SOLUTIONS...WHICH NOW BRING AN AREA OF SHRA/TS UP FROM
NEB/WESTERN IA BY 09Z...EXITING BY 15Z OR SO. THERE STILL WILL BE A
THREAT FOR STRONGER STORMS CAPABLE OF ENHANCED GUSTS...BUT PROBABLY
NOT BASED ON AN ORGANIZED LINE OF STORMS WITH BOWING STRUCTURES.
THERE COULD BE A BREAK FOR THE LATE MORNING/EARLY AFTERNOON HOURS
BEFORE THE PCPN THREAT INCREASES BY 21Z. CONFIDENCE INCREASING
ENOUGH TO INCLUDE SHRA/TS MENTION FOR KRST/KLSE BY THIS TIME...BUT
WILL HANG ONTO SOME VCSH BETWEEN THE MORNING AND LATE AFTERNOON
CONVECTION. AGAIN...SOME THREAT FOR ENHANCED WIND GUSTS LATE
AFTERNOON...BUT NOT ENOUGH CONFIDENCE TO ADD A TEMPO GROUP FOR THIS
AS OF YET.
STORMS AND CLOUDS EXIT SHORTLY AFTER 00Z THU...WITH SKC/SCT VFR
CONDITIONS AND LIGHTER NORTHERLY WINDS THROUGH THE NIGHT TIME HOURS.
&&
.HYDROLOGY...TODAY INTO THIS EVENING
ISSUED AT 318 AM CDT WED JUN 12 2013
FOR AREAS MAINLY ALONG AND SOUTH OF I-90...EXPECTING RAINFALL
AMOUNTS FROM TODAY INTO THIS EVENING IN THE 0.75 TO 1.25 INCH RANGE
WITH THE POSSIBILITY OF LOCALLY HIGHER AMOUNTS IN THUNDERSTORM
ACTIVITY. GIVEN THE WET SOILS IN PLACE...PLAN ON SOME RUNOFF ISSUES
WITH PONDING OF WATER AND SOME SIGNIFICANT WITHIN BANK RIVER RISES.
ANY LONGER DURATION/HIGHER RAINFALL RATES WOULD INCREASE THE
FLOODING POTENTIAL. STAY TUNED.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...DAS
LONG TERM....DAS
AVIATION.....RIECK
HYDROLOGY....DAS
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
250 AM CDT WED JUN 12 2013
.SHORT TERM...
TODAY AND TONIGHT...FORECAST CONFIDENCE MEDIUM TO HIGH
ENTRANCE REGION OF 90 KNOT 250 MB JET MAX OVER THE GREAT LAKES IS
ACROSS CENTRAL/SOUTHERN WISCONSIN TODAY BEFORE AN UPPER LEVEL TROUGH
AXIS WITH A TRAILING 90 KNOT JET MAX PUSHES ACROSS NORTHERN ILLINOIS
TONIGHT.
MAINLY WEAK UPPER DIVERGENCE EARLY THIS MORNING BEFORE AN AREA OF
STRONG UPPER DIVERGENCE MOVES ACROSS SOUTHERN WISCONSIN LATER THIS
MORNING. HOWEVER THIS APPEARS TO HAVE SOME CONVECTIVE FEEDBACK FROM
THUNDERSTORMS OVER NORTHWEST IOWA THAT THE NAM PUSHES EAST ACROSS
WISCONSIN. THIS IS ALSO SEEN AS AN AREA OF CYCLONIC VORTICITY AT
500 MB AHEAD OF THE MAIN MID LEVEL SHORTWAVE THAT MOVES ACROSS
NORTHERN ILLINOIS/SOUTHERN WISCONSIN THIS AFTERNOON AND EVENING.
WHILE THE MAIN 700 MB THERMAL RIDGE MOVES ACROSS NORTHERN
ILLINOIS...SOUTHERN WISCONSIN WILL BE IN A MODERATE TEMPERATURE
GRADIENT. WEAK/MODERATE 700 MB UPWARD MOTION EXISTS ACROSS SOUTHERN
WISCONSIN WITH A STRONGER 15 MICROBAR/SEC AREA LATE THIS AFTERNOON
WITH THE MAIN MID LEVEL TROUGH. THE STRONGER 850 MB/700 MB WINDS
SET UP ACROSS NORTHERN ILLINOIS. WEAK TO MODERATE 850 MB MOISTURE
CONVERGENCE OCCURS OVER SOUTHERN WISCONSIN THROUGH THE MORNING WITH
A STRONGER AREA WITH THE SHORTWAVE THIS AFTERNOON.
PRECIPITABLE WATER VALUES REACH ALMOST 2 INCHES BY EARLY EVENING
OVER MUCH OF SOUTHERN WISCONSIN.
THE RAP AND MOST OF THE MESOSCALE MODELS BRING SCATTERED TO NUMEROUS
SHOWERS/THUNDERSTORMS THIS MORNING WITH THE MAIN MCS MOVING ACROSS
NORTHERN ILLINOIS AND PORTIONS OF SOUTHERN WISCONSIN LATER THIS
AFTERNOON. THIS APPEARS REASONABLE.
THE 04Z HRRR TRIES TO DEVELOP THE NORTHWEST IOWA MCS BUT WEAKENS IT
OVER SOUTHERN WISCONSIN THIS MORNING...AND TAKE THE SOUTH DAKOTA MCS
AND WEAKENS IT INTO A MORE WEST TO EAST AREA OF SHOWERS AND
THUNDERSTORMS.
WHAT MAY HAPPEN IS MORE OF A HEAVY RAIN EVENT WITH THE AFTERNOON MCS
FORMED BY THE SYNOPTIC SHORTWAVE AND ASSOCIATED SURFACE LOW. THE
SPC DAY ONE OUTLOOK HAS A MODERATE RISK JUST SOUTH OF THE WISCONSIN
BORDER WITH A SLIGHT RISK OVER SOUTHERN WISCONSIN. THIS AGREES WITH
THE NEW 00Z CIPS ANALOGS THAT PLACE THE MAJORITY OF THE 30 KNOT WIND
PROBABILITIES AND SEVERE REPORTS TO THE SOUTH OF WISCONSIN...WITH A
FEW WIND SEVERE WIND REPORTS IN FAR SOUTHERN WISCONSIN.
THE SHORTWAVE DROPS INTO NORTHERN INDIANA AFTER MIDNIGHT TONIGHT.
EXPECT A SURGE OF NORTH WINDS ESPECIALLY DOWN LAKE MICHIGAN LATE
THIS EVENING AND TONIGHT.
THURSDAY THROUGH FRIDAY...FORECAST CONFIDENCE HIGH.
A HIGH PRESSURE RIDGE WILL BE MOVING ACROSS THE UPPER MIDWEST AND
GREAT LAKES REGION DURING THIS PERIOD. EXPECT SUNSHINE...LOWER
DEWPOINTS AND LIGHT NORTH TO EAST WINDS. HIGHS WILL BE AROUND
CLIMATOLOGICAL NORMAL INLAND FROM THE LAKE IN THE MID/UPPER 70S.
.LONG TERM...
FRIDAY NIGHT AND SATURDAY...FORECAST CONFIDENCE MEDIUM.
THE UPPER LEVEL RIDGE WILL BE BREAKING DOWN INTO A MORE ZONAL FLOW
PATTERN OVER THE UPPER MIDWEST. A SHORTWAVE TRACKING ALONG THIS
RIDGE WILL MOVE ACROSS IA/IL LATE FRI NIGHT INTO SAT MORNING. A
CLUSTER OF THUNDERSTORMS/MCS SEEMS THE LIKELY MODE OF CONVECTION
WITH THIS FEATURE ON THE NOSE OF THE LOW LEVEL JET. SOUTHERN WI MAY
BE ON THE NORTHERN FRINGE OF THE STRONGER STORMS AND JUST GET THE
RAIN AND ELEVATED THUNDERSTORMS IF THE 00Z ECMWF MODEL SOLUTION PANS
OUT. THE GFS MODEL IS MAINTAINING A MORE NORTHERLY TRACK WHICH WOULD
IMPACT THE ENTIRE MKX FORECAST AREA WITH SHOWERS AND
STORMS...POSSIBLY STRONG.
ANOTHER ROUND OF SHOWERS AND STORMS WILL BE POSSIBLE SATURDAY NIGHT
WITH AN UPPER LEVEL SHORTWAVE TROUGH AND A WEAK SURFACE COLD
FRONT...BUT THIS HAS A PRETTY GOOD CHANCE OF REMAINING SOUTH OF THE
WI/IL BORDER.
SUNDAY THROUGH MONDAY...FORECAST CONFIDENCE MEDIUM.
AN UPPER LEVEL TROUGH WILL SWING DOWN ACROSS THE GREAT LAKES REGION
SUNDAY AND MONDAY. THIS WILL BRING SHOWERS AND THUNDERSTORMS TO MUCH
OF WISCONSIN AHEAD OF AND ALONG A COLD FRONT. THE 00Z ECMWF IS ABOUT
12 HOURS SLOWER THAN THE GFS WITH THIS SYSTEM.
TUESDAY THROUGH WEDNESDAY...FORECAST CONFIDENCE MEDIUM.
ONCE THAT SYSTEM CLEARS WISCONSIN...SURFACE HIGH PRESSURE WILL
SETTLE OVER THE GREAT LAKES REGION AS A RELATIVELY WEAK UPPER LEVEL
RIDGE BUILDS IN OVER THE CENTER OF THE COUNTRY. OVERALL THE WEATHER
WILL BE QUIET FOR SOUTHERN WI...BUT THERE WILL PROBABLY CONTINUE TO
BE A SLIGHT CHANCE FOR THUNDERSTORMS MENTIONED IN THE FORECAST. THIS
IS DUE TO POSSIBLE WEAK RIPPLES IN THE UPPER LEVEL NORTHWEST FLOW
PATTERN OUT AHEAD OF THAT UPPER RIDGE.
&&
.AVIATION/12Z TAFS/...
MAINLY VFR INITIALLY WITH SCATTERED SHOWERS/ISOLATED THUNDERSTORMS.
SOME MVFR/IFR CIGS VISIBILITIES ARE POSSIBLE AS THE SCATTERED
SHOWERS/ISOLATED THUNDERSTORMS BECOME MORE NUMEROUS THIS AFTERNOON.
SOME STORMS COULD BE SEVERE. AS A LOW MOVES ACROSS NORTHERN
ILLINOIS THIS AFTERNOON THE MVFR/IFR CIGS/VSBYS WILL BECOME MORE
NUMEROUS. THE THUNDERSTORM CHANCES WILL END TONIGHT BY MIDNIGHT AS
THE LOW MOVES ACROSS NORTHERN INDIANA.
&&
.MARINE...
SOME CONCERN OF FOG TODAY. WINDS WILL BE LIGHT OVER THE LAKE
AND THE PRESENT AIR MASS IS MOIST. GIVEN THE LIGHT WINDS THAT WILL
VEER FROM THE NORTH TO THE EAST NORTHEAST AND THE AFOREMENTIONED AIR
MASS...INCLUDED PATCHY DENSE FOG IN THE NEARSHORE ZONES. NOT ENOUGH
CONFIDENCE AT THIS TIME TO GO WITH A DENSE FOG ADVISORY. THEN
CONCERN IS INCREASING THUNDERSTORM CHANCES. SOME MAY BE SEVERE.
BRISK NORTH WINDS ON TONIGHT COULD REACH SMALL CRAFT CRITERIA.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...NONE.
&&
$$
TODAY/TONIGHT AND AVIATION/MARINE...HENTZ
THURSDAY THROUGH TUESDAY...MRC
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1105 PM CDT TUE JUN 11 2013
.UPDATE...
ISSUED AT 1105 PM CDT TUE JUN 11 2013
LINES OF CONVECTION DEVELOPING ALONG REGIONS OF CONVERGENCE...MOSTLY
ELEVATED WITH CLOUD BASES AT 10 KFT. DON/T EXPECT A SEVERE THREAT
WITH THESE.
STRONG/SEVERE STORMS STILL LOOK POSSIBLE OVERNIGHT...BUT TAKING A
DIFFERENT SHAPE TO PREVIOUS THINKING. LATEST MESO MODELS LEANING
TOWARD DEVELOPING AN AREA OF SHOWERS/STORMS OVER EASTERN
NEB...TRACKING THIS INTO NORTHEAST IA/SOUTHEAST MN BETWEEN 09-12Z.
THIS IS FUELED BY AN UPPER AIR DISTURBANCE...LOW LEVEL MOISTURE
TRANSPORT AND SOME LINGERING INSTABILITY. SOME STRONG TO POSSIBLY
DAMAGING WIND GUSTS ARE STILL POSSIBLE...WITH DRY SUB CLOUD LAYERS
ALSO FAVORING A WIND THREAT. SOMETHING TO WATCH...BUT FEEL THIS
MIGHT BE MORE OF AN ISOLATED THREAT RATHER THAN WIDESPREAD.
MEANWHILE...A DAMAGING LINE OF BOWING SEGMENTS STILL
POSSIBLE/LIKELY OVER THE NORTHERN PLAINS...BUT WITH THE EXPECTED
COMPLEX OUT AHEAD OF IT...USING UP THE INSTABILITY AND TAPPING THE
LOW LEVEL MOISTURE RETURN...IT PROBABLY WON/T HAVE THE FUEL TO MAKE
IT TO THE FORECAST AREA...LET ALONE WESTERN MN. THAT SAID...THE MCV
WITH THAT SYSTEM COULD BE A PLAYER IN OUR LOCAL WEATHER LATER WED
AFTERNOON. LATEST NAM12 SUGGESTS THAT THIS MCV WILL SPIN ACROSS THE
FORECAST AREA BY LATE AFTERNOON...SPARKING MORE SHOWERS AND STORMS.
THE ATMOSPHERE COULD DESTABILIZE ENOUGH BY THAT TIME THAT SOME
STRONG/SEVERE STORMS WILL AGAIN BECOME A THREAT. LOTS OF IFS WITH
THIS THOUGH...AND THE EVOLUTION OF LATER TONIGHT/WED MORNING WILL
HAVE A LARGE BEARING IN WHAT WE CAN EXPECTED FOR LATER WED.
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 345 PM CDT TUE JUN 11 2013
AT 3 PM...SCATTERED SHOWERS CONTINUED TO BE FOUND FROM THE
EASTERN DAKOTAS SOUTHEAST INTO NORTHEAST ILLINOIS AND SOUTHEAST
WISCONSIN. THESE SHOWERS ARE DEVELOPING ABOVE THE CAP DUE TO WEAK
TO MODERATE 700 TO 300 MB MOISTURE TRANSPORT...WEAK TO MODERATE
310 TO 320K ISENTROPIC UPGLIDE...WEAK TO MODERATE 700 TO 500 MB
FRONTOGENESIS...AND THE RIGHT ENTRANCE REGION OF A 100 KNOT
250 MB JET.
THE 11.12Z MODELS THAT THE 700 MB SHORT WAVE TROUGH OVER THE
CENTRAL DAKOTAS WILL MOVE ACROSS WEST-CENTRAL AND SOUTHWEST `
MINNESOTA LATE THIS AFTERNOON...AND THROUGH OUR AREA FROM LATE
EVENING INTO THE EARLY OVERNIGHT. THE 700 MB VAD WIND AT KABR JUST
RECENTLY WENT FROM WEST TO SOUTHWEST. AHEAD OF THIS WAVE...THE
MODELS CONTINUE TO SHOW THAT THE 700 TO 500 MB FRONTOGENESIS...
700 TO 300 MB MOISTURE TRANSPORT...AND 310 TO 320K ISENTROPIC LIFT
WILL INCREASES ACROSS THE FORECAST AREA. THE HRRR SUGGESTS THAT
SHOWERS AND THUNDERSTORMS WILL BECOME MORE WIDESPREAD ALONG THE
FRONTOGENETIC WING AHEAD OF THIS WAVE BETWEEN 7 PM AND 10 PM IN
SOUTHEAST MINNESOTA...AND THEN SPREADS EAST INTO WESTERN
WISCONSIN MAINLY ALONG THE INTERSTATES OF 90 AND 94 BETWEEN 10 PM
AND 1 AM. AS THE SHORT WAVE MOVES INTO THE AREA EXPECT THE SHOWERS
AND THUNDERSTORMS TO SPREAD INTO NORTHEAST IOWA AND SOUTHWEST
WISCONSIN BETWEEN 11 PM AND 3 AM.
AFTER THIS SYSTEM MOVES THROUGH THE AREA...EXPECT A BREAK AND THEN
LOOKING FOR A MESOSCALE CONVECTIVE COMPLEX /LIKELY TO DEVELOP NEAR
RAPID CITY/ TO MOVE THROUGH THE AREA ON TUESDAY MORNING. THE
MODELS HAVE BEEN REALLY STRUGGLING WITH THE TIMING AND EVOLUTION OF
THIS SYSTEM. A FEW OF THE MESO MODELS HAVE SHOWED THAT A LINE OF
STORMS WOULD MOVE THROUGH THE AREA BETWEEN 5 AM AND 10 AM. 0-3 KM
SHEAR AND THE 700 TO 500 MB LAPSE RATES SUGGEST THAT THERE MAY BE
SOME DAMAGING WINDS ASSOCIATED WITH THIS LINE. MEANWHILE THE
ECMWF AND LATEST HRRR SUGGEST THAT THIS LINE MAY ARRIVE A BIT
LATER AND THAT THE LINE WILL NOT BE THAT STRONG WHEN IT MOVES
THROUGH THE AREA. BY FAR...THE ECMWF IS SLOWEST WITH THIS
SYSTEM...AND BY THE TIME THAT IT ARRIVES THERE IS NOT MUCH
INSTABILITY LEFT. AS A RESULT...THE SEVERE WEATHER THREAT IS STILL
UNCLEAR WITH THIS SYSTEM.
ANOTHER THING THAT WILL HAVE TO BE WATCHED TONIGHT IS THE THREAT
FOR HEAVY RAIN. BOTH THE GFS AND NAM/WRF SHOW THAT THE
PRECIPITABLE WATER VALUES WILL BE INCREASING UP TO 1.8 INCHES AND
THAT THE WARM CLOUD LAYER DEPTHS WILL BE INCREASING INTO THE 4 TO
4.5 KM RANGE. AS A RESULT...EXPECT THE SHOWERS AND THUNDERSTORMS
TO BECOME EFFICIENT RAIN PRODUCERS. WILL ESPECIALLY HAVE TO WATCH
FOR THE POTENTIAL OF TRAINING ALONG THE FRONTOGENETIC BAND.
RAINFALL AMOUNTS FROM 0.75 TO 1.50 INCHES LOOK POSSIBLE FROM
TONIGHT INTO WEDNESDAY MORNING. THERE MAY BE EVEN A FEW SPOTS THAT
COULD SEE UP TO 2 INCHES.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 345 PM CDT TUE JUN 11 2013
ON WEDNESDAY EVENING...THE MOISTURE TRANSPORT QUICKLY MOVES WELL
EAST OF THE AREA AS THE UPPER LEVEL LOW MOVES AWAY FROM THE
REGION. THIS IS BIT FASTER THAN ORIGINALLY EXPECTED...SO LOWERED
THE PRECIPITATION CHANCES DURING THE EVENING AND TOOK THEM OUT FOR
THE OVERNIGHT.
FROM FRIDAY NIGHT INTO THE WEEKEND...THE MODELS CONTINUE TO SHOW
THAT SEVERAL MESOSCALE CONVECTIVE COMPLEXES WILL DEVELOP OVER THE
NORTHERN PLAINS AND THEN MOVE THROUGH THE FORECAST AREA. WHILE
THIS HAS BEEN A CONSISTENT SIGNAL...THE MODELS HAVE BEEN REALLY
STRUGGLE WITH BOTH THEIR LOCATION AND TIMING. AT THIS TIME...THE
MOST CONSISTENT SIGNAL IS FOR FRIDAY NIGHT INTO SATURDAY
MORNING...SO WENT THE HIGHEST PRECIPITATION DURING THIS TIME FRAME.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1105 PM CDT TUE JUN 11 2013
BANDS OF SHRA/TS FIRING ALONG LINES OF CONVERGENCE...MOSTLY WELL
ELEVATED WITH CIGS 10 KFT. SOME CHANGES IN THE MESO MODELS WITH HOW
THEY HANDLE LARGE THUNDERSTORM COMPLEXES EXPECTED TO DEVELOP OVER
THE NEXT FEW HOURS. ENOUGH CONSENSUS THAT WILL LEAN THE TAFS TOWARD
THESE SOLUTIONS...WHICH NOW BRING AN AREA OF SHRA/TS UP FROM
NEB/WESTERN IA BY 09Z...EXITING BY 15Z OR SO. THERE STILL WILL BE A
THREAT FOR STRONGER STORMS CAPABLE OF ENHANCED GUSTS...BUT PROBABLY
NOT BASED ON AN ORGANIZED LINE OF STORMS WITH BOWING STRUCTURES.
THERE COULD BE A BREAK FOR THE LATE MORNING/EARLY AFTERNOON HOURS
BEFORE THE PCPN THREAT INCREASES BY 21Z. CONFIDENCE INCREASING
ENOUGH TO INCLUDE SHRA/TS MENTION FOR KRST/KLSE BY THIS TIME...BUT
WILL HANG ONTO SOME VCSH BETWEEN THE MORNING AND LATE AFTERNOON
CONVECTION. AGAIN...SOME THREAT FOR ENHANCED WIND GUSTS LATE
AFTERNOON...BUT NOT ENOUGH CONFIDENCE TO ADD A TEMPO GROUP FOR THIS
AS OF YET.
STORMS AND CLOUDS EXIT SHORTLY AFTER 00Z THU...WITH SKC/SCT VFR
CONDITIONS AND LIGHTER NORTHERLY WINDS THROUGH THE NIGHT TIME HOURS.
&&
.HYDROLOGY...TONIGHT INTO WEDNESDAY
ISSUED AT 345 PM CDT TUE JUN 11 2013
FOR AREAS MAINLY ALONG AND SOUTH OF INTERSTATE 94 CORRIDOR...PLAN
ON RAINFALL AMOUNTS FROM TONIGHT THROUGH WEDNESDAY TO RANGE FROM
0.75 TO 1.50 INCHES WITH LOCALLY HIGHER AMOUNTS POSSIBLE. WITH WET
SOILS IN PLACE...EXPECT SOME RUNOFF ISSUES AND SOME SIGNIFICANT
WITHIN BANK RIVER RISES TO OCCUR. WILL HAVE TO KEEP A CLOSE EYE
ON ANY AREAS THAT MAY SEE LONGER DURATION/HIGHER RAINFALL RATES
FOR FLOODING POTENTIAL. STAY TUNED.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
UPDATE.......RIECK
SHORT TERM...BOYNE
LONG TERM....BOYNE
AVIATION.....RIECK
HYDROLOGY....BOYNE
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
401 AM MDT WED JUN 12 2013
.SHORT TERM...(TODAY AND THURSDAY)
ISSUED AT 223 AM MDT WED JUN 12 2013
CURRENT WATERVAPOR SATELLITE LOOP SHOWS THE POTENT
SHORTWAVE DISTURBANCE ALOFT...WHICH AIDED IN SEVERE TSTORM
DEVELOPMENT ACROSS THE DAKOTAS AND WESTERN NEBRASKA LAST
NIGHT...PUSHING EASTWARD INTO THE NORTHERN PLAINS AS A SHORT WAVE
RIDGE MOVES INTO THE FORECAST AREA BEHIND THE DISTURBANCE. DRIER
AIR HAS MOVED INTO SOUTHEAST WYOMING AND THE SOUTHERN NEBRASKA
PANHANDLE EARLY THIS MORNING...WHICH SHOULD GREATLY LIMIT DAYTIME
CONVECTION WITH ADDITIONAL MIDLEVEL SUBSIDENCE. HOWEVER...MODELS
SHOW ANOTHER SHORTWAVE MOVING ACROSS THE HIGH PLAINS LATER TODAY
AS A WEAK SURFACE TROUGH/MOISTURE GRADIENT DEVELOPS ALONG THE
LARAMIE RANGE. ALTHOUGH LLVL INSTABILITY IS MARGINAL...KEPT A
SLIGHT CHANCE OF SHOWERS AND TSTORMS ALONG AND JUST EAST OF THE
LARAMIE RANGE TODAY WHERE EAST TO SOUTHEAST WINDS WILL DEVELOP AND
BECOME BREEZY BY LATE THIS AFTERNOON. SOUTHWEST WINDS ARE EXPECTED
WEST OF THE LARAMIE RANGE...AND MAY GUST TO 30-35 MPH AT TIMES.
PATCHY FOG IS POSSIBLE ACROSS MOST OF THE WESTERN NEBRASKA
PANHANDLE TONIGHT AND EARLY THURSDAY MORNING. OTHERWISE...THERE IS
A BETTER CHANCE OF THUNDERSTORMS ON THURSDAY AS THE UPPER LEVEL
FLOW BACKS INTO THE SOUTHWEST AHEAD OF A PACIFIC STORM SYSTEM
PUSHING INTO THE PACIFIC NORTHWEST. THE LLVL CONVERGENCE
BOUNDARY/MOISTURE GRADIENT WILL REMAIN NEAR THE LARAMIE RANGE
DURING THE DAY...WITH PW/S INCREASING OVER 1.00 INCHES ACROSS
WESTERN NEBRASKA. MODELS SHOW MUCH MORE LLVL INSTABILITY...WITH
LI/S AS LOW AS -9C ACROSS NEBRASKA AND CAPE VALUES BETWEEN 2500 TO
3500 J/KG. A FEW STRONG THUNDERSTORMS ARE POSSIBLE THURSDAY
AFTERNOON AS WELL. TEMPERATURES WILL REMAIN ABOVE NORMAL...WITH
VERY LITTLE CHANGE IN HIGH TEMPERATURES WHICH RANGE FROM THE MID
TO UPPER 80S ACROSS SOUTHEAST WYOMING TO THE LOW 90S ACROSS
WESTERN NEBRASKA AND THE NORTH PLATTE RIVER VALLEY.
.LONG TERM...(THURSDAY NIGHT THROUGH TUESDAY)
ISSUED AT 401 AM MDT WED JUN 12 2013
WEATHER PATTERN WILL BE RELATIVELY PERSISTENT THROUGH EARLY NEXT
WEEK WITH AN UPPER LEVEL TROUGH OVER THE NW CONUS AND A RIDGE INTO
THE CENTRAL CONUS. RIDGE WILL FLATTEN OUT EARLY THIS WEEKEND AS
UPPER LEVEL WAVE MOVES OUT OF THE PACIFIC NW AND INTO SOUTH
CENTRAL CANADA BUT THE RIDGE WILL REBOUND BY EARLY NEXT WEEK.
STARTING OFF THURSDAY EVENING THERE WILL BE A SMALL CHANCE FOR
THUNDERSTORMS. COULD SEE AN ISOLATED SHOWER OR THUNDERSTORM OVER
THE MOUNTAINS BUT THE MAIN CONCERN WILL BE ALONG THE EASTERN
FRINGES OF THE FORECAST AREA IN THE NEBRASKA PANHANDLE. COULD SEE
A FEW SEVERE THUNDERSTORMS BUT AT THIS TIME THE GREATEST
INSTABILITY SHOULD BE EAST OF THE FORECAST AREA.
FRIDAY LOOKS WARM AND DRY WITH WILL MINIMAL THUNDERSTORM CHANCES.
MODELS SHOWING A WEAK SHORTWAVE SLIDING JUST SOUTH AND EAST OF THE
AREA WITH A STRONGER WAVE NORTH ACROSS MONTANA. AS LONG AS THE
PLACEMENT OF THESE FEATURES IS CORRECT THEN MOST OF THE AREA WILL
STAY DRY.
FRONTAL BOUNDARY WILL BRING A SHOT OF COOLER AIR FRIDAY NIGHT.
HIGH TEMPERATURES SATURDAY SHOULD BE A GOOD 5 TO 10 DEGREES COOLER
THAN FRIDAY...MAINLY IN THE 80S WITH SOME 70S WEST. TEMPERATURES
WILL SLOWLY REBOUND SUNDAY THROUGH EARLY NEXT WEEK AS THE UPPER
RIDGE BUILDS BACK INTO THE ROCKIES. CHANCES FOR THUNDERSTORMS
WILL MAINLY FOCUS EAST OF THE LARAMIE RANGE...MAINLY LATE
AFTERNOON AND EVENING. IT IS A BIT EARLY TO SAY...BUT GIVEN MODEL
PROJECTIONS FOR INSTABILITY AND SHEAR...SEVERE THUNDERSTORMS LOOK
TO BE GOOD POSSIBILITY SHOULD STORMS DEVELOP.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY EVENING)
ISSUED AT 1029 PM MDT TUE JUN 11 2013
CONVECTION HAS MOVED OFF TO THE EAST THIS EVENING. STILL A CHANCE
OF STRATUS OUT IN THE PANHANDLE TONIGHT...BUT HRRR NOT REALLY
GOING WIDESPREAD WITH ITS FORECAST. WENT AHEAD WITH LOW MVFR IN
THE KAIA AND KCDR TAFS TONIGHT AROUND 10Z THROUGH 15Z. LOOKS
REALLY DRY WEDNESDAY. THE ONLY AREA THAT COULD SEE CONVECTION
TOMORROW WOULD BE THE NORTHERN PANHANDLE.
&&
.FIRE WEATHER...
ISSUED AT 223 AM MDT WED JUN 12 2013
FIRE WEATHER CONCERNS WILL CONTINUE TO BE MINIMAL INTO THIS
WEEKEND MAINLY DUE TO GREEN FUELS. A RIDGE OF HIGH PRESSURE WILL
BUILD OVER THE AREA TODAY AND THURSDAY...WITH MOSTLY DRY
CONDITIONS AND VERY WARM TEMPERATURES CONTINUING. DAYTIME MIN
HUMIDITIES WILL REMAIN IN THE TEENS IN SOUTHEAST WYOMING...MAINLY
WEST OF THE LARAMIE RANGE...WITH 20 TO 40 PERCENT EXPECTED ACROSS
THE HIGH PLAINS INTO WESTERN NEBRASKA. WINDY CONDITIONS WILL
CONTINUE ALONG AND WEST OF THE LARAMIE RANGE THROUGH THIS TIME AS
WELL...WITH GUSTS OF 30 TO 40 MPH COMMON IN THE AFTERNOON EACH
DAY.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&
$$
SHORT TERM...TJT
LONG TERM...LIEBL
AVIATION...CLAYCOMB
FIRE WEATHER...TJT
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
1033 PM MDT TUE JUN 11 2013
.SHORT TERM...(TONIGHT THROUGH WEDNESDAY NIGHT)
ISSUED AT 405 PM MDT TUE JUN 11 2013
RADAR AND VISIBLE SATELLITE TRENDS SHOW CONVECTION TRYING TO
DEVELOP ALONG THE LEESIDE PRESSURE TROUGH/DRYLINE WHICH IS NOW
POSITIONED FROM EASTERN CONVERSE COUNTY IN WYOMING DOWN TO THE
SOUTHEAST IN CENTRAL KIMBALL COUNTY IN NEBRASKA. LAPS AND SPC MESO
ANALYSIS OF MLCAPE BOTH SHOW THE CAP ERODING JUST TO THE EAST OF
THIS BOUNDARY WITH A STRONGER CAP FURTHER EAST INTO NEBRASKA. 50+
KTS OF DEEP LAYER SHEAR IS BEING ANALYZED OVER THIS AREA AS
WELL...WITH LLVL SHEAR ON THE WEAK SIDE. STILL EXPECTING
CONVECTION TO STRENGTHEN AND INCREASE IN COVERAGE THROUGH THE LATE
AFTERNOON JUST EAST OF THE DRYLINE WHERE 1000 TO 1500 J/KG MLCAPE
IS IN PLACE WITH A SLOWLY WEAKENING CAP. RECENT RAP AND HRRR MODEL
RUNS AGREE WITH THE IDEA OF WIDELY SCATTERED SHOWERS AND STORMS LATE
THIS AFTERNOON AND EARLY EVENING MOVING EAST-NORTHEAST AHEAD OF
THE DRYLINE WITH LLVL SHEAR INCREASING MAINLY ACROSS THE NORTHERN
AND EASTERN PANHANDLE. AS A RESULT...WILL NOT MAKE ANY CHANGES TO
THIS MORNINGS UPDATE FOR A FEW STORMS TO BECOME SEVERE THROUGH
THIS EVENING...WITH THE HIGHEST POTENTIAL FOR SEVERE IN THE NORTHERN
PANHANDLE COUNTIES.
FURTHER WEST...WEST TO SOUTHWEST WINDS WILL CONTINUE TO GUST 35 TO
50 MPH AS THE UPPER LEVEL WAVE MOVES OVERHEAD THIS AFTERNOON AND
PUSHES THE LEESIDE PRESSURE TROUGH TO THE EAST. WINDS WILL
DIMINISH TONIGHT BEHIND A WEAK COOL FRONT MOVING SOUTH ACROSS THE
EASTERN PLAINS AFTER MIDNIGHT. A VERY MOIST BOUNDARY LAYER BEHIND
THE FRONT...COMBINED WITH ANY OUTFLOW FROM THIS EVENINGS
THUNDERSTORMS...WILL PRODUCE PATCHY AREAS OF FOG MAINLY IN LOW
LYING AREAS OF THE NEBRASKA PANHANDLE LATE TONIGHT AS SFC WINDS
DIMINISH.
SFC WINDS WILL SHIFT TO THE NORTH BEHIND THE FRONT TONIGHT...THEN
SOUTHEAST THROUGH WEDNESDAY AFTERNOON ACROSS THE EASTERN PLAINS WITH
CONTINUED BREEZY SOUTHWEST WINDS WEST OF THE LARAMIE RANGE. THE
UPPER LEVEL RIDGE WILL REBUILD OVER THE FORECAST AREA WITH A WEAK
PIECE OF ENERGY MOVING UP FROM THE SOUTHWEST IN THE LATER AFTERNOON.
A FEW STORMS COULD FIRE OVER THE LARAMIE RANGE AS SFC WINDS TURN TO
THE SOUTHEAST...ALTHOUGH COOLER SFC TEMPS BEHIND THE FRONT WILL KEEP
CONDITIONS MORE STABLE ACROSS THE EASTERN PLAINS. DECREASING WINDS
AND A CONTINUED MOIST BOUNDARY LAYER WILL ONCE AGAIN PRODUCE PATCHY
FOG OVER THE PANHANDLE ON WEDNESDAY NIGHT.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT PM MDT TUE JUN 11 2013
THE 12Z MODEL SOLUTIONS ARE REASONABLY CONSISTENT SHOWING THE UPPER
RIDGE SLOWLY TRANSLATING EASTWARD ACROSS THE GREAT PLAINS THURSDAY
AND FRIDAY. MEANWHILE...A TROUGH AND UPPER LOW OVER THE PACIFIC
NORTHWEST PIVOT EAST TO NORTHEAST THROUGH THE NORTHERN ROCKIES AND
INTO SOUTHERN CANADA INTO THE WEEKEND. THIS WILL FLATTEN THE RIDGE
OVER THE FRONT RANGE. A RIDGE AXIS THEN REBUILDS ALONG THE FRONT
RANGE AND ADJACENT PLAINS EARLY NEXT WEEK.
THE MAIN SURFACE WEATHER FEATURE OF THE LONG TERM WILL BE A MEANDERING
DRY LINE/TROUGH SEPARATING MOIST UNSTABLE AIR TO THE EAST FROM MUCH
DRIER AIR TO THE WEST. THIS BOUNDARY WILL BE DRIFTING EAST FROM THE
EASTERN WYOMING PLAINS INTO THE WESTERN PANHANDLE THURSDAY AS A
PACIFIC FRONT MOVES THROUGH THE CWFA LATE THURSDAY NIGHT AND FRIDAY
MORNING. ISOLATED CONVECTION WILL DEVELOP DURING THE EARLY AFTERNOON
ALONG THE LARAMIE RANGE AND MOVE EAST ONTO THE PLAINS FROM MID
AFTERNOON INTO THE EVENING. THIS FRONTAL PASSAGE WILL SHIFT WINDS
TO WESTERLY WITH DRIER AIR INFILTRATING MUCH OF THE REGION. THE
FRONT WILL STALL OVER WESTERN NEBRASKA FRIDAY AFTERNOON. WEAK
INSTABILITY AND SOME LOW LEVEL MOISTURE NEAR THE FRONT MAY TRIGGER A
FEW TSTORMS OVER THE SOUTHERN PANHANDLE FRIDAY AFTERNOON AND EARLY
EVENING. THE SURFACE TROUGH DRIFTS WEST INTO FAR SOUTHEAST WYOMING
SATURDAY AFTERNOON. LOW LEVEL CONVERGENCE NEAR THE LARAMIE RANGE MAY
TRIGGER ISOLATED TSTORMS. OTHERWISE...IT WILL REMAIN DRY. THE DRY LINE
DRIFTS EAST INTO THE WESTERN PANHANDLE WITH ISOLATED DIURNAL CONVECTION
POSSIBLE. BOTH MONDAY AND TUESDAY WILL FEATURE ISOLATED AFTERNOON AND
EVENING CONVECTION ALONG AND EAST OF THE LARAMIE RANGE.
TEMPERATURES THROUGHOUT THE LONG TERM WILL AVERAGE ABOVE SEASONAL
NORMALS. THURSDAY WILL BE THE WARMEST DAY WITH HIGHS FROM 85 TO 95.
FRIDAY AND SATURDAY WILL TREND SLIGHTLY COOLER WITH THE PASSAGE OF
THE PACIFIC FRONT. TEMPERATURES WARM SOMEWHAT SUNDAY THROUGH TUESDAY
WITH THE INFLUENCE FROM THE UPPER RIDGE.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY EVENING)
ISSUED AT 1029 PM MDT TUE JUN 11 2013
CONVECTION HAS MOVED OFF TO THE EAST THIS EVENING. STILL A CHANCE
OF STRATUS OUT IN THE PANHANDLE TONIGHT...BUT HRRR NOT REALLY
GOING WIDESPREAD WITH ITS FORECAST. WENT AHEAD WITH LOW MVFR IN
THE KAIA AND KCDR TAFS TONIGHT AROUND 10Z THROUGH 15Z. LOOKS
REALLY DRY WEDNESDAY. THE ONLY AREA THAT COULD SEE CONVECTION
TOMORROW WOULD BE THE NORTHERN PANHANDLE.
&&
.FIRE WEATHER...
ISSUED AT 405 PM MDT TUE JUN 11 2013
A WEATHER DISTURBANCE MOVING TOWARD THE DISTRICT
TODAY WILL BRING A CHANCE FOR THUNDERSTORMS ACROSS THE
EASTCENTRAL PLAINS OF WYOMING AND THE NEBRASKA PANHANDLE THIS
AFTERNOON AND EVENING. STRONG WINDS...LIGHT TO MODERATE RAIN...AND
SOME HAIL WILL OCCUR WITH THESE THUNDERSTORMS.
GUSTY WEST TO SOUTHWEST WINDS AND DRY CONDITIONS WILL CONTINUE
THROUGH THIS EVENING ALONG AND WEST OF THE LARAMIE RANGE WHERE
HUMIDITIES HAVE DROPPED TO BETWEEN 6 AND 14 PERCENT AND WINDS ARE
GUSTING 35 TO 45 MPH THIS AFTERNOON. WINDS WILL EASE AND
HUMIDITIES WILL RECOVER TO BETWEEN 30 AND 50 PERCENT TONIGHT. A
RIDGE OF HIGH PRESSURE WILL BUILD OVER THE DISTRICT ON WEDNESDAY
AND THURSDAY...AND SO MOSTLY DRY AND WARM TEMPERATURES WILL
CONTINUE THROUGH THIS TIME. HUMIDITIES WILL REMAIN IN THE TEENS TO
LOW 20S IN SOUTHEAST WYOMING...WITH 20 TO 30 PERCENT EXPECTED IN
THE NEBRASKA PANHANDLE. WINDS WILL REMAIN ON THE WINDY SIDE ALONG
AND WEST OF THE LARAMIE RANGE THROUGH THIS TIME AS WELL...WITH
GUSTS OF 30 TO 40 MPH COMMON IN THE AFTERNOON EACH DAY. FURTHER
EAST...WINDS WILL BE OUT OF THE SOUTHEAST AND WILL GUST 20 TO 30
MPH IN THE AFTERNOON.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&
$$
SHORT TERM...RJM
LONG TERM...MAJ
AVIATION...CLAYCOMB
FIRE WEATHER...RJM
AREA FORECAST DISCUSSION
NWS TALLAHASSEE FL
1104 AM EDT Wed Jun 12 2013
.DISCUSSION...
The 13 UTC regional surface analysis showed an area of high
pressure across much of the Gulf Coast, and a weak trough from the
GA coast through the FL Big Bend. Vapor imagery and upper air data
showed very dry air above 700mb, as our forecast area remains
under the dry, sinking northwest flow under the eastern periphery
of the central CONUS ridge.
The relatively warm, dry air aloft and large scale subsidence will
make it difficult for significant cumulus growth today, and the
MOS consensus PoP and Convection Allowing Models (CAM) PoP are 20%
or less for this afternoon. However, as was the case 24 hours ago,
the HRRR and 11 UTC local WRF are much more bullish in developing
deep moist convection. We`re discounting the local WRF, as its
boundary conditions (from the RAP) resulted in unrealistically high
surface moisture (i.e. dewpoints of around 80 deg). The HRRR, on
the other hand, did an outstanding job yesterday, so we have
subjectively blended in its solution with the other, drier NWP
guidance. The resulting PoP is nearly identical to what we had
yesterday, 20-30% from I-10 to the coast. While most updrafts
struggled to get any depth yesterday, a few storms did manage to
develop impressive hail cores. We think that will be case today,
as some of the CAM solutions have updraft speeds exceeding 20 m/s.
Of course the limited cloud cover will result in above-average
temperatures, with highs in the mid to upper 90s. Deep vertical
mixing will allow surface moisture to decrease a bit this
afternoon, so maximum heat index values will be around 105 deg.
&&
.AVIATION [through 12 UTC Thursday]...
Prevailing VFR conditions are expected through this TAF cycle.
Widely scattered TSRA will develop between 18 UTC and 00 UTC,
mainly between I-10 and the coast. Thus there is a slight chance
of TSRA at KTLH and KECP.
&&
.HYDROLOGY...
After the recent heavy rainfall across the area, two river points
are at or expected to reach Action Stage. The Ochlockonee River near
Thomasville is at Action stage, and will crest early Friday morning
then start to recede. The Little River near Hahira is expected to
reach Action Stage early Monday morning. With little precipitation
expected over the next couple of days, impacts to area rivers will
be minimal.
&&
.PRELIMINARY POINT TEMPS/POPS...
Tallahassee 95 72 96 74 / 20 10 20 20
Panama City 90 76 91 78 / 30 10 20 20
Dothan 97 74 99 74 / 10 10 10 20
Albany 97 74 99 74 / 10 20 10 30
Valdosta 97 72 99 73 / 10 10 20 30
Cross City 93 72 93 74 / 20 10 20 10
Apalachicola 89 75 89 77 / 30 10 10 10
&&
.TAE WATCHES/WARNINGS/ADVISORIES...
AL...NONE.
GA...NONE.
FL...NONE.
GM...NONE.
&&
$$
HYDROLOGY...Navarro/Harrigan
REST OF DISCUSSION...Fournier
AREA FORECAST DISCUSSION...UPDATED
NWS MIAMI FL
730 AM EDT WED JUN 12 2013
.AVIATION...
EARLY MORNING CONVECTION ACROSS THE ATLANTIC WATERS REMAINS NEARLY
STATIONARY AND IS EXPECTED TO REMAIN OFFSHORE THROUGH THE MORNING.
WINDS ARE EXPECTED TO BE LIGHT AND VARIABLE ACROSS THE AREA THROUGH
THE EARLY TO MID MORNING HOURS BEFORE TURNING MORE EASTERLY ACROSS
THE EAST COAST TERMINALS. FLOW WILL AGAIN BE RATHER WEAK ALLOWING
FOR GOOD CONVERGENCE WITH THE GULF BREEZE. EXPECT SCATTERED
SHRAS/TSRAS MAINLY ACROSS INTERIOR AREAS BUT COULD APPROACH ALL TAF
SITES LATE IN THE AFTERNOON. KEPT VCTS MENTION FOR NOW. ISOLATED IFR
CONDITIONS WILL BE POSSIBLE WITH ANY TSRA THAT AFFECTS ANY TAF SITE.
&&
.AVIATION...BNB/CD
.PREV DISCUSSION... /ISSUED 320 AM EDT WED JUN 12 2013/
SHORT TERM (TODAY-FRIDAY)...
THE LATEST MODEL GUIDANCE INDICATES THE UPPER LEVEL PATTERN BECOMING
MORE AMPLIFIED ACROSS THE COUNTRY BY THE END OF THE SHORT-TERM
PERIOD AS SEVERAL SHORTWAVE TROUGHS DIG SOUTHEAST FROM THE GREAT
LAKES TO THE SOUTHEAST AND AN UPPER RIDGE BUILDS OVER THE MID-WEST.
AT THE SURFACE...THE LOCAL AREA WILL REMAIN IN A WEAKNESS WITHIN THE
SUBTROPICAL RIDGE WITH WEAK LOW-LEVEL STEERING FLOW CONTINUING. A
WEAK FRONTAL BOUNDARY ASSOCIATED WITH A SHORTWAVE TROUGH IS FORECAST
TO SAG SOUTH OVER THE STATE BY THE END OF THE PERIOD.
FOR TODAY...THE WEAK LOW-LEVEL FLOW COMBINED WITH A SUFFICIENT
AMOUNT OF MOISTURE AND INCREASING INSTABILITY DUE TO COOLER
MID/UPPER LEVEL TEMPERATURES (H5 -10 C INLAND) SPREADING SOUTH OVER
THE AREA WILL LIKELY TRANSLATE TO ANOTHER ROUND OF SCATTERED SHOWERS
AND STORMS THIS AFTERNOON. A FEW OF THESE STORMS MAY BECOME STRONG
WITH THE MAIN THREATS BEING GUSTY WINDS AND HAIL.
ADDITIONALLY...WITH THE WEAK STEERING FLOW IN PLACE AND VERY
LITTLE STORM MOTION WITH THE ACTIVITY THAT DOES DEVELOP COULD LEAD
TO LOCALIZED FLOODING. ALTHOUGH THE HI-RES MODEL REFLECTIVITIES
DISPLAY QUITE THE SPREAD AS TO WHERE THE AFTERNOON CONVECTION WILL
BECOME CONCENTRATED...THE MORE RELIABLE HRRR SOLUTION GENERALLY
INDICATES THE BULK OF THIS ACTIVITY SETTING UP OVER THE INTERIOR
AREAS BEGINNING AROUND 16-19Z.
THURSDAY THROUGH FRIDAY...ALTHOUGH SIMILAR CONDITIONS WILL
PERSIST...MID-LEVEL TEMPERATURES ARE FORECAST TO WARM BACK TO AROUND
OR JUST ABOVE AVERAGE. PRECIPITABLE WATER VALUES ARE ALSO FORECAST
TO TREND DOWNWARD TOWARD 1.5". THE SFC RIDGE IS FORECAST TO STEADILY
SHIFT SOUTHWARD...WHICH WILL LEAD TO LIGHT SWRLY LOW-LEVEL FLOW
AHEAD OF THE AFOREMENTIONED FRONTAL BOUNDARY SAGGING SOUTH INTO THE
STATE BY FRIDAY AFTERNOON. DESPITE THE MORE STABLE AND SLIGHTLY
DRIER CONDITIONS...AFTERNOON SHOWERS/TSTMS...MAINLY ISOLATED IN
COVERAGE...MAY FAVOR THE EAST COAST METRO AREAS WITH THE SW FLOW
SETTING UP THROUGH THIS TIME.
LONG TERM (FRIDAY NIGHT-TUESDAY)...
THE MODELS GENERALLY INDICATE RISING UPPER HEIGHTS ALONG WITH SOME
DRIER MID/UPPER AIR OVER THE WEEKEND. HIGH PRESSURE BUILDING EAST
NORTH OF THE AREA IN THE WAKE OF THE PREVIOUSLY DISCUSSED FRONTAL
BOUNDARY WILL LEAD TO EASTERLY LOW-LEVEL FLOW RETURNING ACROSS THE
AREA. PRECIPITABLE WATER VALUES ARE FORECAST TO DIP DOWN BELOW 1.25"
THROUGH THE WEEKEND AND INTO MONDAY. THIS WILL LEAD TO DRIER AND
WARMER CONDITIONS ACROSS THE AREA. ANY AFTERNOON SHOWERS THAT
DEVELOP SHOULD REMAIN INLAND WITH THE EASTERLY FLOW SETTING UP.
AVIATION...
WINDS ARE EXPECTED TO BE LIGHT AND VARIABLE ACROSS THE AREA THROUGH
THE EARLY TO MID MORNING HOURS BEFORE TURNING MORE EASTERLY ACROSS
THE EAST COAST TERMINALS. FLOW WILL AGAIN BE RATHER WEAK ALLOWING
FOR GOOD CONVERGENCE WITH THE GULF BREEZE. EXPECT SCATTERED
SHRAS/TSRAS MAINLY ACROSS INTERIOR AREAS BUT COULD APPROACH ALL TAF
SITES LATE IN THE AFTERNOON. KEPT VCTS MENTION FOR NOW. ISOLATED IFR
CONDITIONS WILL BE POSSIBLE WITH ANY TSRA THAT AFFECTS ANY TAF SITE.
MARINE...
HIGH PRESSURE RIDGE WILL STEADILY SHIFT SOUTH OVER THE MARINE AREA
THROUGH THE END OF THE WEEK AS A WEAK FRONTAL BOUNDARY APPROACHES
FROM THE NORTH. AS A RESULT...LIGHT WINDS AND LOW SEAS WILL BE
EXPECTED TO CONTINUE.
FIRE WEATHER...
PLENTY OF MOISTURE WILL KEEP THE RH VALUES WELL ABOVE CRITICAL
LEVELS EACH DAY.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 89 76 89 76 / 20 20 20 20
FORT LAUDERDALE 88 77 89 76 / 20 20 20 20
MIAMI 89 77 90 75 / 20 20 20 20
NAPLES 89 74 88 74 / 20 20 20 20
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
DISCUSSION/MARINE/FIRE...85/AG
AVIATION/RADAR...10/CD
AREA FORECAST DISCUSSION
NWS PEACHTREE CITY GA
1034 AM EDT WED JUN 12 2013
.UPDATE...
I HAVE ADJUSTED SOME OF THE GRIDS FOR TODAY...MAINLY POPS/WEATHER.
MODEL SOUNDINGS HAVE BEEN INDICATING THAT THE MID-LEVEL CAP WOULD
REMAIN STRONGLY IN PLACE OVER NORTH AND CENTRAL GEORGIA THROUGH
TODAY. THE 12Z SOUNDING FROM KFFC SHOWS THE MID-LEVEL CAP TO BE
SIGNIFICANTLY WEAKER THAN EXPECTED WITH ONLY MINIMAL CIN IN THE
VICINITY OF THE LFC. STILL...WE ARE UNDER THE EASTERN EDGE OF THE
UPPER-LEVEL RIDGE AND SOME INHIBITION WILL LIKELY CONTINUE THROUGH
TODAY. IF ANY STORMS MANAGE TO BREAK THROUGH THIS AFTERNOON...
INSTABILITY IS MODERATE WITH CAPE AROUND 2000 J/KG AND LI/S IN THE -4
TO -6 DEGREE RANGE SO AN ISOLATED STRONG STORM OR TWO WOULD NOT BE
IMPOSSIBLE. NO SIGNIFICANT CHANGES MADE TO THE REMAINDER OF THE GRIDS
AS CURRENT FORECAST TRENDS LOOK PRETTY GOOD.
&&
.PREV DISCUSSION... /ISSUED 733 AM EDT WED JUN 12 2013/
PREV DISCUSSION...
SHORT TERM /TODAY THROUGH THURSDAY/...
/ISSUED 405 AM EDT WED JUN 12 2013/
ANOTHER HOT DAY ACROSS THE CWA AS THE AREA REMAINS UNDER THE EASTERN
EDGE OF AN UPPER LEVEL RIDGE. SOME DECENT UNCERTAINTY IN THE POP
FORECAST FOR TODAY. GFS SHOWS A STRONG VORT MAX ROUNDING THE UPPER
LEVEL RIDGE AND BRINGS IT INTO NORTH GEORGIA BY MID MORNING. GFS
ISNT GENERATING MUCH IN TERMS OF PRECIP WITH IT THOUGH ACROSS THE
CWA. NAM SHOWS SOME REFLECTION OF A SHORTWAVE BUT IS WEAKER AND
GENERALLY FURTHER EAST. EVEN HARDER TO PICK OUT THE FEATURE IN THE
ECMWF. DESPITE THIS THOUGH...ECMWF AND NAM ARE THE HIGHEST IN TERMS
OF PRECIP CHANCES ACROSS NORTH GEORGIA TODAY. HRRR IS PICKING UP ON
SOME ACTIVITY IN NORTH GEORGIA ASSOCIATED WITH THIS. FOR THE
FORECAST TRIED TO MEET IN THE MIDDLE AND HAVE SHOWN SLIGHT CHANCE OF
SHOWERS AND THUNDERSTORMS ACROSS THE NORTH. LEE SIDE TROUGH APPEARS
IT SHOULD BE JUST SOUTH OF THE CWA THIS AFTERNOON AND IF SOMETHING
WERE TO DEVELOP...THINK IT SHOULD BE ALONG THIS BOUNDARY...SO KEPT
MENTION OF POPS OUT OF CENTRAL GEORGIA.
THURSDAY IS THE BETTER CHANCE OF RAIN IN THE SHORT TERM AS A STRONG
SHORTWAVE MOVES FROM THE OHIO VALLEY INTO THE MID ATLANTIC AND A
COLD FRONT MOVES INTO GEORGIA. MODELS ARE IN GOOD AGREEMENT WITH THE
COLD FRONT MOVING INTO THE NORTH THURSDAY MORNING AND INTO CENTRAL
GEORGIA BY THE EVENING. DECENT INSTABILITY WITH THE SYSTEM WITH THE
GFS SHOWING ML CAPE AROUND 2000 J/KG. LL SHEAR IS NON-ZERO WITH
AROUND 20KTS ACROSS CENTRAL GEORGIA. WITH THE INSTABILITY...A
BOUNDARY TO FOCUS ON AND UPPER LEVEL SUPPORT...ISOLD SEVERE STORMS
ARE POSSIBLE ON THURSDAY WITH THE MAIN THREATS BEING WIND AND HAIL.
TOTAL RAINFALL AMOUNTS SHOULD BE MINIMAL...AROUND A QUARTER INCH OR
LESS WITH LOCALLY HIGHER AMOUNTS IN SOME OF THE THUNDERSTORMS.
BOTH AHN AND ATL SAW THEIR FIRST 90 DEGREE DAY FOR THE YEAR
YESTERDAY AND ALL OF NORTH AND CENTRAL GEORGIA IS EXPECTED TO REACH
THE LOW TO MID 90S AGAIN TODAY EXCEPT FOR THE MOUNTAINS. EVEN WITH
THE FRONT EXPECTED ON THURSDAY...MOST PLACES WILL HAVE TIME AHEAD OF
THE RAIN TO REACH THE 90S AGAIN. SOME OF CENTRAL GEORGIA WILL REACH
HEAT INDICES OF 100-102 THIS AFTERNOON WHICH FALLS SHORT OF A HEAT
ADVISORY /105 DEGREES OR GREATER HEAT INDICES FOR TWO CONSECUTIVE
DAYS/...BUT IT WILL STILL BE HOT AND FOLKS SHOULD KEEP THIS IN MIND
WHEN WORKING OUTSIDE AS ITS EXPECTED TO BE THE HOTTEST DAY OF THE
SEASON SO FAR.
11
LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
/ISSUED 405 AM EDT WED JUN 12 2013/
A COLD FRONT WILL BE CLOSE TO CENTRAL GA AND MOVING S STARTING
THURSDAY NIGHT WITH POTENTIAL FOR SEVERE STORMS ASSOCIATED. THE
FRONT EXITS THE FORECAST AREA LATER THURSDAY NIGHT WITH THE GFS THE
FASTEST...THE NAM NEXT AND THE EUROPEAN THE SLOWEST.
PRECIP CHANCES MOST LIKELY WILL HAVE ENDED FOR FRIDAY ALTHOUGH THE
EUROPEAN HOLDS ONTO CHANCES OVER CENTRAL GA. SATURDAY IS DRY AS HIGH
PRESSURE ALOFT OVER THE LOWER MS VALLEY HELPS FOR HOLD ANY
CONVECTION AT BAY...HOWEVER NW FLOW ALOFT IS OVER THE AREA BUT
APPEARS TO HAVE ONLY MINIMAL MOISTURE. SUNDAY APPEARS ONE OF THOSE
DAYS WHERE YOU COULD GO EITHER WAY WITH 20 PERCENT POPS OVER THE NW
HALF OR SO OF THE AREA AS THE UPPER RIDGE FLATTENS AND SOME
INSTABILITY DEVELOPS WITH MINIMAL MOISTURE. FOR NOW WILL JUST HOLD
ONTO 10 PERCENT ACROSS THE NW. THE SOUTHERN EDGE OF THE WESTERLIES
RETURN FOR MONDAY AND TUESDAY WITH INCREASED MOISTURE AND INSTABILITY
ACROSS THE AREA AND THE POSSIBILITY FOR SHORT WAVES TO ENHANCE THE
POTENTIAL FOR SCATTERED SHOWERS AND THUNDERSTORMS. A WEAK COLD FRONT
MAY GET INTO N GA FOR WEDNESDAY.
BDL
AVIATION...
12Z UPDATE...
EXCEPT FOR SOME MVFR VSBYS THIS MORNING DUE TO FOG...VFR
CONDITIONS ARE EXPECTED THROUGH THE TAF PERIOD. BIGGEST
UNCERTAINTY IS IN REGARDS TO THE PRECIPITATION FORECAST FOR TODAY.
HAVE A DISTURBANCE ROUNDING THE EDGE OF THE UPPER RIDGE AND MODELS
DIFFER ON IF CONVECTION WILL MOVE INTO GEORGIA. FOR NOW...THINKING
IS ANY CONVECTION THAT DEVELOPS WILL REMAIN NORTH AND EAST OF THE
TERMINALS. OF ALL THE SITES THOUGH...AHN AGAIN WOULD BE MOST
LIKELY TO SEE AN ISOLD THUNDERSTORM. OVERALL SHOULD SEE NW
WINDS...HOWEVER ONE MODEL IS PICKING UP AT A BRIEF PERIOD OF NE
AND THUS THE REASON FOR MEDIUM CONFIDENCE ON WINDS.
//ATL CONFIDENCE...12Z UPDATE...
HIGH CONFIDENCE ON CIGS AND VSBYS. MEDIUM CONFIDENCE ON WINDS.
MEDIUM CONFIDENCE ON ISOLD CONVECTION STAYING OUT OF THE
TERMINAL.
11
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 95 70 94 67 / 30 30 50 20
ATLANTA 92 74 92 68 / 30 30 50 30
BLAIRSVILLE 88 67 86 59 / 30 30 50 20
CARTERSVILLE 93 70 93 65 / 30 30 50 20
COLUMBUS 95 75 96 73 / 30 30 20 40
GAINESVILLE 91 72 91 66 / 30 30 50 20
MACON 95 71 96 69 / 30 30 20 40
ROME 94 70 92 66 / 30 30 50 10
PEACHTREE CITY 92 69 93 67 / 30 30 50 30
VIDALIA 96 75 97 73 / 30 30 20 40
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...20
LONG TERM....TDP
AVIATION...20
AREA FORECAST DISCUSSION...UPDATED
NWS PEACHTREE CITY GA
733 AM EDT WED JUN 12 2013
.PREV DISCUSSION...
SHORT TERM /TODAY THROUGH THURSDAY/...
/ISSUED 405 AM EDT WED JUN 12 2013/
ANOTHER HOT DAY ACROSS THE CWA AS THE AREA REMAINS UNDER THE EASTERN
EDGE OF AN UPPER LEVEL RIDGE. SOME DECENT UNCERTAINTY IN THE POP
FORECAST FOR TODAY. GFS SHOWS A STRONG VORT MAX ROUNDING THE UPPER
LEVEL RIDGE AND BRINGS IT INTO NORTH GEORGIA BY MID MORNING. GFS
ISNT GENERATING MUCH IN TERMS OF PRECIP WITH IT THOUGH ACROSS THE
CWA. NAM SHOWS SOME REFLECTION OF A SHORTWAVE BUT IS WEAKER AND
GENERALLY FURTHER EAST. EVEN HARDER TO PICK OUT THE FEATURE IN THE
ECMWF. DESPITE THIS THOUGH...ECMWF AND NAM ARE THE HIGHEST IN TERMS
OF PRECIP CHANCES ACROSS NORTH GEORGIA TODAY. HRRR IS PICKING UP ON
SOME ACTIVITY IN NORTH GEORGIA ASSOCIATED WITH THIS. FOR THE
FORECAST TRIED TO MEET IN THE MIDDLE AND HAVE SHOWN SLIGHT CHANCE OF
SHOWERS AND THUNDERSTORMS ACROSS THE NORTH. LEE SIDE TROUGH APPEARS
IT SHOULD BE JUST SOUTH OF THE CWA THIS AFTERNOON AND IF SOMETHING
WERE TO DEVELOP...THINK IT SHOULD BE ALONG THIS BOUNDARY...SO KEPT
MENTION OF POPS OUT OF CENTRAL GEORGIA.
THURSDAY IS THE BETTER CHANCE OF RAIN IN THE SHORT TERM AS A STRONG
SHORTWAVE MOVES FROM THE OHIO VALLEY INTO THE MID ATLANTIC AND A
COLD FRONT MOVES INTO GEORGIA. MODELS ARE IN GOOD AGREEMENT WITH THE
COLD FRONT MOVING INTO THE NORTH THURSDAY MORNING AND INTO CENTRAL
GEORGIA BY THE EVENING. DECENT INSTABILITY WITH THE SYSTEM WITH THE
GFS SHOWING ML CAPE AROUND 2000 J/KG. LL SHEAR IS NON-ZERO WITH
AROUND 20KTS ACROSS CENTRAL GEORGIA. WITH THE INSTABILITY...A
BOUNDARY TO FOCUS ON AND UPPER LEVEL SUPPORT...ISOLD SEVERE STORMS
ARE POSSIBLE ON THURSDAY WITH THE MAIN THREATS BEING WIND AND HAIL.
TOTAL RAINFALL AMOUNTS SHOULD BE MINIMAL...AROUND A QUARTER INCH OR
LESS WITH LOCALLY HIGHER AMOUNTS IN SOME OF THE THUNDERSTORMS.
BOTH AHN AND ATL SAW THEIR FIRST 90 DEGREE DAY FOR THE YEAR
YESTERDAY AND ALL OF NORTH AND CENTRAL GEORGIA IS EXPECTED TO REACH
THE LOW TO MID 90S AGAIN TODAY EXCEPT FOR THE MOUNTAINS. EVEN WITH
THE FRONT EXPECTED ON THURSDAY...MOST PLACES WILL HAVE TIME AHEAD OF
THE RAIN TO REACH THE 90S AGAIN. SOME OF CENTRAL GEORGIA WILL REACH
HEAT INDICES OF 100-102 THIS AFTERNOON WHICH FALLS SHORT OF A HEAT
ADVISORY /105 DEGREES OR GREATER HEAT INDICES FOR TWO CONSECUTIVE
DAYS/...BUT IT WILL STILL BE HOT AND FOLKS SHOULD KEEP THIS IN MIND
WHEN WORKING OUTSIDE AS ITS EXPECTED TO BE THE HOTTEST DAY OF THE
SEASON SO FAR.
11
LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
/ISSUED 405 AM EDT WED JUN 12 2013/
A COLD FRONT WILL BE CLOSE TO CENTRAL GA AND MOVING S STARTING
THURSDAY NIGHT WITH POTENTIAL FOR SEVERE STORMS ASSOCIATED. THE
FRONT EXITS THE FORECAST AREA LATER THURSDAY NIGHT WITH THE GFS THE
FASTEST...THE NAM NEXT AND THE EUROPEAN THE SLOWEST.
PRECIP CHANCES MOST LIKELY WILL HAVE ENDED FOR FRIDAY ALTHOUGH THE
EUROPEAN HOLDS ONTO CHANCES OVER CENTRAL GA. SATURDAY IS DRY AS HIGH
PRESSURE ALOFT OVER THE LOWER MS VALLEY HELPS FOR HOLD ANY
CONVECTION AT BAY...HOWEVER NW FLOW ALOFT IS OVER THE AREA BUT
APPEARS TO HAVE ONLY MINIMAL MOISTURE. SUNDAY APPEARS ONE OF THOSE
DAYS WHERE YOU COULD GO EITHER WAY WITH 20 PERCENT POPS OVER THE NW
HALF OR SO OF THE AREA AS THE UPPER RIDGE FLATTENS AND SOME
INSTABILITY DEVELOPS WITH MINIMAL MOISTURE. FOR NOW WILL JUST HOLD
ONTO 10 PERCENT ACROSS THE NW. THE SOUTHERN EDGE OF THE WESTERLIES
RETURN FOR MONDAY AND TUESDAY WITH INCREASED MOISTURE AND INSTABILITY
ACROSS THE AREA AND THE POSSIBILITY FOR SHORT WAVES TO ENHANCE THE
POTENTIAL FOR SCATTERED SHOWERS AND THUNDERSTORMS. A WEAK COLD FRONT
MAY GET INTO N GA FOR WEDNESDAY.
BDL
&&
.AVIATION...
12Z UPDATE...
EXCEPT FOR SOME MVFR VSBYS THIS MORNING DUE TO FOG...VFR
CONDITIONS ARE EXPECTED THROUGH THE TAF PERIOD. BIGGEST
UNCERTAINTY IS IN REGARDS TO THE PRECIPITATION FORECAST FOR TODAY.
HAVE A DISTURBANCE ROUNDING THE EDGE OF THE UPPER RIDGE AND MODELS
DIFFER ON IF CONVECTION WILL MOVE INTO GEORGIA. FOR NOW...THINKING
IS ANY CONVECTION THAT DEVELOPS WILL REMAIN NORTH AND EAST OF THE
TERMINALS. OF ALL THE SITES THOUGH...AHN AGAIN WOULD BE MOST
LIKELY TO SEE AN ISOLD THUNDERSTORM. OVERALL SHOULD SEE NW
WINDS...HOWEVER ONE MODEL IS PICKING UP AT A BRIEF PERIOD OF NE
AND THUS THE REASON FOR MEDIUM CONFIDENCE ON WINDS.
//ATL CONFIDENCE...12Z UPDATE...
HIGH CONFIDENCE ON CIGS AND VSBYS. MEDIUM CONFIDENCE ON WINDS.
MEDIUM CONFIDENCE ON ISOLD CONVECTION STAYING OUT OF THE
TERMINAL.
11
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 95 70 94 67 / 20 10 50 20
ATLANTA 92 74 92 68 / 10 10 50 30
BLAIRSVILLE 88 67 86 59 / 20 20 50 20
CARTERSVILLE 93 70 93 65 / 10 10 50 20
COLUMBUS 95 75 96 73 / 10 10 20 40
GAINESVILLE 91 72 91 66 / 20 20 50 20
MACON 95 71 96 69 / 10 10 20 40
ROME 94 70 92 66 / 20 10 50 10
PEACHTREE CITY 92 69 93 67 / 10 10 50 30
VIDALIA 96 75 97 73 / 10 5 20 40
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...11
LONG TERM....BDL
AVIATION...11
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1043 AM CDT WED JUN 12 2013
.MESOSCALE DISCUSSION...
1042 AM CDT
...WIDESPREAD SEVERE WEATHER OUTBREAK ACROSS THE REGION EXPECTED
LATE THIS AFTERNOON AND EVENING INCLUDING TORNADIC POTENTIAL IN
NORTH CENTRAL IL LATE THIS AFTERNOON...
SEVERE WEATHER THREAT CONTINUES WITH OBSERVATIONAL TRENDS HINTING
MORE AT PRECISE EVOLUTION AND TIMING.
WHAT LEFTS OF OVERNIGHT DECAYING MCS IS MOVING FROM SOUTHEAST WI
OVER LAKE MI. VISIBLE SATELLITE AND REGIONAL RADAR MOSAIC
INDICATE SOME BRIEF SUPPRESSION BEHIND THIS WHILE THERE IS AN AXIS
EXTENDING SOUTHWARD ON RADAR OF LIKELY SOME MID-LEVEL CONVERGENCE.
THERE HAS NOT BEEN ANY DEVELOPMENT ALONG THIS THUS FAR BUT CANNOT
RULE OUT A FEW ELEVATED STORMS THROUGH 3 PM OR SO ACROSS FAR
NORTHERN AND NORTHEAST IL.
THE SURFACE LOW PRESSURE IS DEVELOPING NORTHEASTWARD INTO SOUTHWEST
AND CENTRAL IA AS OF 10 AM WITH A WARM FRONT EVOLVING EAST
NORTHEAST FROM THERE. THIS LOOKS TO BE FROM NEAR WATERLOO IA TO
SAVANNA IL AND THEN BECOMING MORE ILL-DEFINED EAST OF THERE INTO
THE CWA. DEW POINTS IN THE LOWER 70S ARE ADVECTING UP TO THIS
BOUNDARY WITH WINDS STRONGLY BACKED TO THE NORTH OF THIS. THERE
HAS BEEN GROWTH IN THE CU ACROSS IA NEAR THIS DEVELOPING FRONT.
AS THE MAIN VORT MAX AND MID-LEVEL SPEED MAX MOVE EAST FROM
EASTERN SD/NORTHEAST NE...DEVELOPMENT OF ROBUST CONVECTION IS
HIGHLY LIKELY BY MID AFTERNOON ACROSS NE IA/SW WI/NW IL. SUPERCELL
DEVELOPMENT WOULD BE A FAVORED MODE ALONG AND IMMEDIATELY NORTH OF
THE WARM FRONT. FURTHER NORTH AND NORTHEAST FROM THE TWIN CITIES
TO MILWAUKEE...ELEVATED CONVECTION MAY INCREASE. ALL OF THIS IS
SLIGHTLY FURTHER NORTH THAN EARLIER ANTICIPATED...BUT THE SEVERE
WEATHER THREAT HAS NOT DIMINISHED FOR OUR AREA...JUST FOCUSED MORE
SO IN THE LATE AFTERNOON AND EVE.
GIVEN THE ANTICIPATED EVOLUTION MENTIONED ABOVE WHICH HAS THE
SUPPORT OF THE RAP AND SEVERAL CONVECTIVE-ALLOWING MODELS...NORTH
CENTRAL IL WILL LIKELY BE UNDER THE GUN LATE THIS AFTERNOON. THIS
INCLUDES THE ROCKFORD AREA DURING RUSH HOUR AS STORMS EVOLVE
EASTWARD IN A FAVORED COMBINATION OF DISCRETE TO SMALL SCALE
CLUSTERS. TORNADIC POTENTIAL WILL CERTAINLY EXIST WITH THESE GIVEN
THE HELICITY RICH AIR NEAR THE BOUNDARY AND ANTICIPATED SURFACE-
BASED CAPE. CONVECTIVE TEMPERATURES FOR THIS ARE FORECAST TO BE
AROUND 80 DEGREES ON THE RAP. WHILE TEMPERATURE TRENDS HAVE BEEN
SLOW TO CLIMB ACROSS THE AREA THUS FAR...SOME THINNING OF THE
CLOUDS AND THE NORTHWARD PUSH OF THE WARM SECTOR SHOULD ALLOW THAT
TO OCCUR.
THE EVENING TIME PERIOD SHOULD SEE THE MOST COVERAGE OF SEVERE
CONVECTION IN THE FORECAST AREA AND WILL BE THE PRIME TIME FOR
CHICAGOLAND. THE LOW-LEVEL JET IS FORECAST TO INCREASE TO 40-50 KT
AND POINT INTO THE ONGOING CONVECTION. SOME SCATTERED CONVECTIVE
DEVELOPMENT...POTENTIALLY SEVERE AND SURFACE BASED...EAST AND
SOUTH OF THIS IS FAVORED DURING THE EVE. SUFFICIENT DEEP LAYER
SHEAR AND RICH LOW-LEVEL MOISTURE WILL OFFER AMPLE WIND THREAT
WITH THE ORGANIZED CONVECTIVE CLUSTERS. WITH THE SURFACE LOW
PROJECTED TO TRACK EAST NEAR THE I-88 CORRIDOR...THERE IS
INCREASING LIKELIHOOD THAT THE MAIN MCV/MCS WILL DEVELOP NEAR THIS
CORRIDOR AS WELL. A MAJORITY OF THE EXPLICIT GUIDANCE DOES
INDICATE THIS. VERY HEAVY RAINFALL AND AN ENHANCED WIND THREAT
WILL EXIST WITH THIS...WHICH WOULD LIKELY IMPACT CHICAGO IN THE
6-10 PM TIME FRAME.
MTF
&&
.DISCUSSION...
304 AM CDT
...MAJOR SEVERE WEATHER OUTBREAK LIKELY THIS AFTERNOON AND
EVENING...WITH HEAVY RAINFALL ALSO LIKELY...
EVERYTHING LINING UP FOR A SIGNIFICANT SEVERE WEATHER OUTBREAK
TODAY. SPC DAY 1 OUTLOOK HAS ENTIRE FORECAST AREA IN MODERATE RISK
OF SEVERE WITH SIGNIFICANT WIND...HAIL...AND TORNADO THREAT. AT THE
SURFACE...LOW PRESSURE OVER THE PLAINS WITH A WEAK WARM FRONT
EXTENDING EAST INTO NORTHERN IL EARLY THIS MORNING. THE LOW WILL
MOVE EAST ALONG THE IA/MO BOARDER TODAY...AND ACROSS NORTHERN IL
THIS EVENING. VERY MOIST LOW LEVEL AIR WITH SURFACE DEW POINTS IN
THE MID AND UPPER 60S IN PLACE. MAY SEE DEWPOINTS POOL IN THE LOWER
70S SOUTH OF WARM FRONT THIS AFTERNOON. THE BOUNDARY WILL INTENSIFY
AS SOUTHWEST LOW LEVEL FLOW INCREASES SOUTH OF THE FRONT AND SURFACE
WINDS BACK TO SE OR E NORTH OF THE BOUNDARY. THIS WILL PULL MODIFIED
MARINE AIR BACK ACROSS FAR NORTHERN IL. HAVE SOME CONCERNS ABOUT HOW
FAR NORTH THE WARM FRONT WILL TRAVEL. SPC DISCUSSION SUGGESTING THE
BOUNDARY WILL MOVE INTO SOUTHERN WI BUT WITH MODELS TAKING LOW
ACROSS I-80 CORRIDOR AND COOLING INFLUENCE OF LAKE
MICHIGAN...THINKING FRONT WONT GET MUCH FARTHER NORTH THAN A
DIXON-GARY LINE. THIS MAY LIMIT NORTHERN EXTEND OF SIGNIFICANT
SEVERE THREAT. THE BOUNDARY WILL ALSO RESULT IN A CHALLENGING
TEMPERATURE FORECAST...WITH TEMPS REACHING LOWER 90S FAR SOUTHERN
PART OF FORECAST AREA...WHILE AREAS ALONG THE NORTH SHORE WILL
LIKELY BE 20 DEGREES COOLER. IT APPEARS THAT MOST OF THE OVERNIGHT
EARLY MORNING CONVECTION WILL AFFECT WI...BUT KEEPING AN EYE ON
MCS OVER WESTERN IA WHICH COULD MOVE INTO NORTHERN IL THIS
MORNING. EARLIER CONVECTION OVER EASTERN IA WEAKENED AS IT MOVED
EAST AND THINK THIS MCS MAY DO THE SAME. CLOUD DEBRIS SHOULD
REMAIN NORTH ALLOWING AREAS SOUTH OF THE WARM FRONT TO HEAT UP
SIGNIFICANTLY...INTO THE UPPER 80S TO LOWER 90S. THIS COULD RESULT
IN SURFACE BASED CAPE OF 3000+ THIS AFTERNOON. FAIRLY VIGOROUS
SHORT WAVE MOVING INTO WESTERN SD/NE EARLY THIS MORNING WILL BE
MOVING ACROSS NORTHERN IL THIS EVENING. MODEL SOUNDINGS SHOW
FAIRLY STOUT CAP EARLY IN THE DAY ERODES THIS AFTERNOON WITH
APPROACHING SHORT WAVE. LOOKING AT 0-6KM BULK SHEAR 50-60 KTS BY
THIS EVENING. WITH INCREASING LOW LEVEL FLOW THIS AFTERNOON AND
BACKING SURFACE WINDS ALONG THE BOUNDARY...SHOULD PRODUCE AN
ENVIRONMENT FAVORABLE FOR DAMAGING WINDS...LARGE HAIL...AND
TORNADOES. SOME OF THE SHORT RANGE HI RES GUIDANCE IS SUGGESTING
DISCRETE STORMS INITIALLY THIS AFTERNOON. EXPECT THE TORNADO
THREAT TO BE MAINLY DURING THE AFTERNOON. STORMS WILL LIKELY
CONGEAL INTO AN MCS AND BECOME MORE OF A HIGH WIND WITH EMBEDDED
QLCS TORNADO THREAT IN THE EVENING. THE OTHER CONCERN IS WITH
PWATS AROUND 2 INCHES...AND SURFACE DEW POINTS NEAR
70...THUNDERSTORMS WILL BE CAPABLE OF VERY HEAVY RAINFALL AND AS
MCS DEVELOPS...FLOODING WILL ALSO BE A CONCERN. MODEL CONSENSUS IS
TO PLACE HEAVIEST QPF NORTH OF THE BOUNDARY OVER THE RFD AND
CHICAGO AREAS. SEE HYDRO SECTION OF THE AFD BELOW.
AFTER THE PASSAGE OF THIS SYSTEM...CENTRAL US RIDGE SHARPENS
BRINGING MUCH DRIER AND COOLER NORTHWEST FLOW FOR THU AND FRI.
EVENTUALLY PACNW UPPER LOW MOVES EAST ACROSS THE CANADIAN PRAIRIES
WHICH WILL PUSH THE RIDGE AXIS EASTWARD AND FLATTEN IT OUT. THUS A
FEW MORE ROUNDS OF THUNDERSTORMS ARE LIKELY TO RETURN SATURDAY AND
SUNDAY AND POSSIBLY INTO MONDAY BEFORE UPPER LOW OPENS INTO A
POTENT SHORT WAVE AND DROPS SOUTHEAST THROUGH THE GREAT LAKES.
ALLSOPP
&&
.HYDROLOGY...304 AM CDT
HAVE ISSUED A FLASH FLOOD WATCH FOR AREAS GENERALLY NORTH OF A
DIXON TO VALPARAISO LINE. THERE IS THE POTENTIAL FOR WIDESPREAD HEAVY
RAINFALL OF 2 TO 3 INCHES ACROSS THIS AREA...WITH LOCALLY UP TO 5
INCHES. THE AXIS OF HEAVIEST RAIN WILL BE OVER THE HIGHLY
URBANIZED ROCKFORD AND CHICAGO METRO AREAS. ALSO CONCERNED FOR THE
POTENTIAL OF VERY HIGH RAINFALL RATES IN SOME OF THE HEAVIER DOWNPOURS.
ALLSOPP
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 14Z...
* STRONG TO SEVERE THUNDERSTORM POTENTIAL LATER TODAY AND INTO
THIS EVENING...WITH SHOWERS/THUNDERSTORMS INCREASING AFTER 18Z.
* POTENTIAL FOR VERY HEAVY RAIN THIS EVENING...WITH IFR VIS AND
CIGS POSSIBLE FOR A PERIOD.
* VARIABLE WINDS FROM ORD TO MDW POSSIBLE...WITH A GENERAL
SOUTHEAST DIRECTION EXPECTED FOR BOTH TERMINALS THROUGH MID DAY.
THEN EXPECT MDW TO REMAIN SOUTHEAST WHILE ORD GOES NORTHEAST BY
18-19Z.
RODRIGUEZ
//DISCUSSION...UPDATED 12Z...
FORECAST CHALLENGES THIS MORNING CONTINUE TO CENTER AROUND TIMING
THE ONSET OF THUNDERSTORM ACTIVITY TODAY.
A COMPLEX OF THUNDERSTORMS ACROSS IOWA DEVELOPED EARLIER THIS
MORNING ALONG THE NOSE OF A LOW LEVEL JET. THIS ACTIVITY HAS BEEN
WEAKENING OVER THE PAST COUPLE HOURS. HOWEVER...THIS ACTIVITY HAS
ENHANCED A MID LEVEL DISTURBANCE (MCV) ACROSS NORTHERN IOWA. THIS
LEAD DISTURBANCE COULD ACT TO SPARK OFF SOME SCT CONVECTION ACROSS
FAR NORTHERN ILLINOIS LATER THIS MORNING. CONFIDENCE IS LOW WITH
THE POTENTIAL FOR THIS EARLIER ACTIVITY. HOWEVER...I FELT THAT A
VCSH MENTION WAS JUSTIFIED AFTER 15 UTC.
OTHERWISE...THE ONLY OTHER CHANCES TO NEW TAFS WAS TO ADD A VCTS
AFTER 20 UTC...A COUPLE HOURS EARLIER THAN THE PREVIOUS 22 UTC
TIMING. THIS WAS MAINLY DUE TO THE POTENTIAL FOR ACTIVITY TO FIRE
ALONG THE SURFACE FRONT. IT APPEARS THAT AS THE SURFACE FLOW
INCREASES OFF THE LAKE TO THE NORTH OF THE WARM FRONTAL BOUNDARY
THAT LOW LEVEL CONVERGENCE WILL STRENGTHEN...AND THIS COULD BE
ENOUGH TO FIRE OFF ACTIVITY BY EARLY TO MID AFTERNOON.
BY FAR THE BEST CHANCES FOR THUNDERSTORMS WILL BE LATER THIS
AFTERNOON AND EVENING. THIS IS THE TIME WHEN THE BEST DYNAMICS
ASSOCIATED WITH THE MAIN DISTURBANCE SHOULD OVERSPREAD THE AREA.
SEVERE THUNDERSTORMS WITH LARGE HAIL...DAMAGING WINDS...AND EVEN
TORNADO`S ARE STILL POSSIBLE. VERY HEAVY RAINFALL WILL ALSO LIKELY
ACCOMPANY THESE STORMS...ESPECIALLY THIS EVENING. THIS COULD LEAD
TO LOCALIZED FLOODING AND REDUCTIONS IN THE VIS DOWN UNDER 2
MILES. IT APPEARS THAT THIS ACTIVITY COULD LAST FOR A 3 TO 6 HOUR
WINDOW INTO THIS EVENING BEFORE CONDITIONS BEGIN TO IMPROVE
OVERNIGHT.
KJB
//ORD AND MDW CONFIDENCE...UPDATED 14Z...
* MEDIUM TO HIGH CONFIDENCE IN CHANCES FOR THUNDERSTORMS LATER
TODAY AND TONIGHT...BUT LOW MEDIUM CONFIDENCE ON THE ONSET
TIMING.
* MODERATE CONFIDENCE IN A PERIOD OF VERY HEAVY RAINFALL WITH
LOWER VIS AND CIGS THIS EVENING.
* MEDIUM CONFIDENCE IN WIND SPEED AND DIRECTION.
RODRIGUEZ
//OUTLOOK FOR ORD/MDW FOR 00Z FRIDAY-12Z WEDNESDAY...UPDATED 12Z...
THURSDAY NIGHT AND FRIDAY...VFR. WX NIL.
SAT THRU MON...VFR. CHC TSRA WITH LOCAL MVFR/IFR.
TUESDAY...VFR.
KJB
&&
.MARINE...
229 AM CDT
THE MAIN FORECAST CONCERNS ON THE LAKE IS THE THREAT FOR SEVERE
THUNDERSTORMS THIS AFTERNOON AND EVENING...ESPECIALLY ACROSS
SOUTHERN LAKE MICHIGAN...AND ALSO A PERIOD OF STRONG NORTHERLY WINDS
LATE TONIGHT AND ON THURSDAY.
DENSE FOG REMAINS ACROSS THE LAKE...ESPECIALLY ACROSS THE NORTHERN
HALF OF THE LAKE....AND I REALLY DONT SEE ANY IMPROVEMENT IN THESE
CONDITIONS UNTIL EITHER LATE THIS AFTERNOON OR THIS EVENING...WHEN
THE WINDS START TO BECOME NORTHERLY. THEREFORE...I HAVE EXTENDED THE
ADVISORY FOR THE OPEN WATERS THROUGH THIS AFTERNOON.
SEVERE THUNDERSTORMS LOOK TO BE A GOOD BET THIS AFTERNOON AND
EVENING...ESPECIALLY ACROSS SOUTHERN LAKE MICHGAN. THESE STORMS WILL
BE CAPABLE OF PRODUCING VERY LARGE HAIL AND STRONG DAMAGING WINDS
IN EXCESS OF 50 KT. THE THREAT OF SEVERE STORMS IS QUITE HIGH...SO
KEEP UP TO DATE ON THE LATEST WEATHER INFORMATION.
A SURFACE LOW IS EXPECTED TO PASS SOUTH OF THE LAKE TONIGHT. THIS
WILL SET UP SOME STRONG NORTHERLY WINDS UP TO 30 KT LATE TONIGHT AND
ON THURSDAY. THIS WILL LIKELY RESULT IN SMALL CRAFT ADVISORY
CONDITIONS FOR THE ILLINOIS AND INDIANA NEAR SHORE WATERS DURING THIS
TIME. CONDITIONS SHOULD BEGIN TO IMPROVE ON FRIDAY AS THE WINDS
ABATE AS A SURFACE RIDGE OF HIGH PRESSURE BUILDS ACROSS THE
LAKE.
KJB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...FLASH FLOOD WATCH...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-ILZ011-
ILZ012-ILZ013-ILZ014-ILZ020-ILZ022...4 PM WEDNESDAY TO 4 AM
THURSDAY.
IN...FLASH FLOOD WATCH...INZ001-INZ002...4 PM WEDNESDAY TO 4 AM
THURSDAY.
LM...DENSE FOG ADVISORY...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-
LMZ565-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-
LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 4 PM
WEDNESDAY.
SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742...1 AM THURSDAY TO 4
PM THURSDAY.
SMALL CRAFT ADVISORY...LMZ743-LMZ744-LMZ745...4 AM THURSDAY TO
11 PM THURSDAY.
&&
$$
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AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1044 AM EDT WED JUN 12 2013
LATEST UPDATE...
UPDATE
.SYNOPSIS...
ISSUED AT 330 AM EDT WED JUN 12 2013
AS LOW PRESSURE MOVES EAST FROM THE PLAINS TOWARD NORTHERN INDIANA
TODAY SHOWERS AND THUNDERSTORMS WILL DEVELOP. SOME OF THE STORMS
COULD BE STRONG TO SEVERE ESPECIALLY SOUTH OF I-94 WITH HIGH WINDS
THE MAIN THREAT. HEAVY RAIN WILL BE POSSIBLE THIS AFTERNOON AND
EVENING TOO SOUTH OF I-96. QUIETER WEATHER WILL RETURN THURSDAY
THROUGH SATURDAY AS THE LOW MOVES EAST AND NORTH WINDS ADVECT DRIER
AIR INTO LOWER MICHIGAN.
&&
.UPDATE...
ISSUED AT 1043 AM EDT WED JUN 12 2013
MY CURRENT THINKING IS THE BEST THREAT FOR SEVERE STORMS WILL BE
THIS EVENING INTO EARLY TONIGHT. THE DENSE MID AND HIGH CLOUD
COVER OVER MN/WI/LWR MI WILL CAUSE THE BEST DESTABILIZATION TO BE
WELL SOUTH OF OUR AREA THIS AFTERNOON. SO... THE STRONGEST
THUNDERSTORMS WILL BE ASSOCIATED WITH THE MAIN UPPER LEVEL WAVE
MOVING THROUGH THIS EVENING. THIS IDEA IS SUPPORTED BY THE LATEST
12Z NAM...12Z HRRR...00Z SPC WRF...12 RAP MODELS.
THE BEST FORCING (MOISTURE TRANSPORT VECTORS 1000/850...LOW LEVEL
JET AND THERMAL GRADIENT...HIGHEST MIXED LAYER CAPE) ARE ALL WELL
SOUTH OF INTERSTATE 94 AND ACTUALLY NEAR AND SOUTH OF INTERSTATE
80 AS THE UPPER WAVE MOVES THROUGH EARLY TONIGHT. WE SHOULD SEE
SOME CONVECTION OVER OUR SRN ONE OR TWO ROWS OF COUNTIES MID
EVENING AS THE WAVE MOVES IN. DEFORMATION ZONE RAIN WILL FOLLOW
DURING THE OVERNIGHT HOURS. THE HEAVIEST OF THAT WILL BE NEAR AND
SOUTH OF INTERSTATE 94.
THERE IS A CONVECTIVE COMPLEX OVER E CNTL MN AT 10 AM HEADING
EAST. THAT IS ON THE TAIL OF THE PV MAX ASSOCIATED WITH THE
CONVECTION THAT CROSSED MN AND WI EARLIER AND HAS SINCE DIED. THAT
PV MAX MOVES THROUGH OUR CNTL CWA THIS AFTERNOON. I BELIEVE THAT
WILL BE THE FOCUS FOR OUR AFTERNOON CONVECTION. THE INSTABILITY IS
MARGINAL (LOOKING AT RAP SOUNDING THIS AFTERNOON) FOR THIS
CONVECTION SO I DO NOT BELIEVE THIS WILL BE SEVERE... MOSTLY JUST
GENERIC THUNDERSTORMS.
&&
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 330 AM EDT WED JUN 12 2013
FORECAST CONCERNS DEAL WITH CONVECTIVE TRENDS THIS MORNING THROUGH
THIS EVENING.
LATEST REGIONAL RADAR SHOWS THAT STORMS HAVE FIRED AS EXPECTED IN
NORTHEAST NEBRASKA ON THE NOSE OF A STRONG LLJ. THESE STORMS HAVE
MOVED INTO NW IOWA. A BIT FARTHER NORTH OVER SOUTH DAKOTA ANOTHER
AREA OF STORMS IS MOVE EWD. THESE ARE ASSOCIATED WITH A SHORT WAVE
MOVING ACROSS THE NRN PLAINS. SHORT RANGE MODELS MOVE THIS SHORT
WAVE SEWD TOWARD CHICAGO BY THIS AFTERNOON AT THE SAME TIME THE SFC
LOW IN SRN NEBRASKA IS MOVING ENEWD. HRRR SHOWS BOTH CLUSTERS OF
STORMS WEAKENING AS THEY MOVE EAST WITH THE IOWA CONVECTION MOVING
TO THE WRN CWA BY NOON OR SO AS MOSTLY SHOWERS.
CONVECTION REDEVELOPS OVER NW IOWA BY EARLY AFTERNOON AS STRONG
DYNAMICS TAKE SHAPE. SBCAPE AROUND 3K J/KG COUPLED WITH STRONG
MOISTURE CONVERGENCE...60-70KTS BULK SHEAR AND LIFT FROM THE
APPROACHING SHORT WAVE SHOULD RESULT IN STRONG TO SEVERE STORMS
DEVELOPING OVER ILLINOIS AND MOVING ESE TOWARD THE SRN CWA. A 50KT
MID LEVEL JET WILL PUSH THE STORMS EWD...PERHAPS AS A DERECHO. CAN/T
ARGUE TOO MUCH WITH THE POSITION OF THE DAY ONE SLIGHT AND MODERATE
RISK AREAS. THIS ISN/T A SLAM DUNK BY ANY MEANS BUT THE HIGHEST
THREAT FOR STRONG/SVR STORMS WILL BE SOUTH OF A MUSKEGON TO LANSING
LINE. LATEST NAM ALSO PUSHES THE WARM FRONT INTO THE SRN CWA THIS
AFTERNOON. SO...WITH THE WARM FRONT IN PLACE WE CAN/T RULE OUT A
TORNADO EITHER.
THE SVR THREAT WILL END THIS EVENING AS THE LOW MOVES BY TO THE
SOUTH AND QUIETER WEATHER WILL RETURN THURSDAY AND FRIDAY.
.LONG TERM...(FRIDAY NIGHT THROUGH TUESDAY)
ISSUED AT 330 AM EDT WED JUN 12 2013
UPPER RIDGING WILL EXTEND FROM THE GULF COAST NORTH INTO THE UPPER
MID WEST FRIDAY NIGHT. THE RIDGING WILL BE FLATTENED THROUGH THE
LONG TERM AS A SERIES OF SHORTWAVE/S CREST THE RIDGE AND MOVE
THROUGH THE GREAT LAKES REGION. THE FIRST OF WHICH MOVES INTO THE
AREA ON SATURDAY. THE SECOND AND MORE SUBSTANTIAL WAVE DIGS INTO THE
GREAT LAKES REGION SUNDAY INTO MONDAY.
AT THE SURFACE RIDGING WILL BE IN PLACE FRIDAY NIGHT AND BRING DRY
WEATHER. THE HIGH SLIPS EAST QUICKLY ON SATURDAY WHICH SHOULD ALLOW
CHANCES FOR SHOWERS AND STORMS DURING THE AFTERNOON AHEAD OF THE
UPPER SHORTWAVE. THE CHANCES WILL CONTINUE INTO SATURDAY NIGHT AS A
WAVE OF LOW PRESSURE SLIDES THROUGH THE AREA AT THE SURFACE.
SUNDAY INTO MONDAY CHANCES FOR SHOWERS AND STORMS WILL CONTINUE AS
THE SECOND MORE POTENT UPPER TROUGH DIGS INTO THE GREAT LAKES.
SURFACE FEATURES ARE BIT MORE HARD TO DISCERN IN THIS TIME FRAME AS
THE GFS IS FURTHER NORTH AND DEEPER WITH THE SURFACE WAVE. FOLLOWED
THE GFS CLOSER HERE AS IT MAKES MORE SENSE TO HAVE A DEEPER FARTHER
NORTH WAVE GIVEN THE UPPER PATTERN. WE LOOK TO DRY OUT MONDAY NIGHT
INTO TUESDAY AS HIGH PRESSURE BUILDS IN.
TEMPERATURES THROUGH THE PERIOD SHOULD BE SEASONABLE DESPITE THE
RIDGING DAMPENING OUT. HEIGHTS ARE STILL FAIRLY HIGH AND 850MB TEMPS
ARE FORECAST TO BE IN THE TEENS C. HIGHS SHOULD BE IN THE UPPER 70S
TO AROUND 80 EACH DAY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 747 AM EDT WED JUN 12 2013
MAIN CONCERN TODAY WILL BE THUNDERSTORM EVOLUTION...COVERAGE AND
SEVERITY. VFR CEILINGS ARE IN PLACE AT DAYBREAK...WITH SOME MVFR
VSBY/S IN FOG. THE EXPECTATION IS THE FOG WILL LIFT THIS
MORNING...GIVING WAY TO VFR CONDITIONS BY LATE MORNING. SOME
SCATTERED SHOWERS ARE EXPECTED THROUGH THE MORNING...BUT MOST WILL
BE LIGHT AND NOT IMPACT CONDITIONS MUCH.
THE FOCUS THIS AFTERNOON AND EVENING IS ON THUNDERSTORMS. A COUPLE
SCENARIOS ARE IN PLAY WITH STORMS SWEEPING IN OFF OF LAKE MICHIGAN
AS EARLY AS NOON TO 100PM. THEY WOULD MOVE THROUGH THE TAF SITES
THIS AFTERNOON WITH THE POTENTIAL FOR SIGNIFICANT WIND
GUSTS...OVER 50 KNOTS. A SECOND SCENARIO WOULD HAVE THE STORMS SWEEP
IN LATER THIS EVENING WITH A MAINLY DRY AFTERNOON. BOTH SCENARIOS
WILL HAVE SIGNIFICANT WIND POTENTIAL AS WELL AS HAIL. ANY STORMS
THAT DEVELOP TODAY COULD BE SEVERE. NORTHERLY WINDS WILL DEVELOP
TONIGHT IN THE WAKE OF THE STORMS WITH MVFR CEILINGS AND POSSIBLY
VSBY/S (FOG) DEVELOPING.
USED VCTS IS THIS MORNING/S TAFS GIVEN THE UNCERTAINTY. LATER
UPDATES WILL PROVIDE GREATER DETAIL.
&&
.MARINE...
ISSUED AT 330 AM EDT WED JUN 12 2013
FAIRLY LIGHT WINDS WILL CONTINUE OVER THE LAKE RESULTING IN LOW WAVE
HEIGHTS. PATCHY DENSE FOG IS POSSIBLE DUE TO HIGH DEWPOINTS OVER THE
COLDER WATER SFC. NORTH WINDS WILL DEVELOP THURSDAY AND A SMALL
CRAFT ADVISORY MAY BE NEEDED.
&&
.HYDROLOGY...
ISSUED AT 330 AM EDT WED JUN 12 2013
THE MAIN PERIOD OF CONCERN IS THIS AFTERNOON AND EVENING. HEAVY
RAINFALL WILL BE POSSIBLE ACROSS THE SRN HALF OF THE CWA DURING THIS
TIME. AN INCH TO TWO INCHES SEEMS PLAUSIBLE ESPECIALLY SOUTH OF
I-94. THIS MAY LEAD TO LOCALIZED FLOODING.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&
$$
UPDATE...WDM
SYNOPSIS...93
SHORT TERM...93
LONG TERM...DUKE
AVIATION...DUKE
HYDROLOGY...93
MARINE...93
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
747 AM EDT WED JUN 12 2013
LATEST UPDATE...
AVIATION
.SYNOPSIS...
ISSUED AT 330 AM EDT WED JUN 12 2013
AS LOW PRESSURE MOVES EAST FROM THE PLAINS TOWARD NORTHERN INDIANA
TODAY SHOWERS AND THUNDERSTORMS WILL DEVELOP. SOME OF THE STORMS
COULD BE STRONG TO SEVERE ESPECIALLY SOUTH OF I-94 WITH HIGH WINDS
THE MAIN THREAT. HEAVY RAIN WILL BE POSSIBLE THIS AFTERNOON AND
EVENING TOO SOUTH OF I-96. QUIETER WEATHER WILL RETURN THURSDAY
THROUGH SATURDAY AS THE LOW MOVES EAST AND NORTH WINDS ADVECT DRIER
AIR INTO LOWER MICHIGAN.
&&
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 330 AM EDT WED JUN 12 2013
FORECAST CONCERNS DEAL WITH CONVECTIVE TRENDS THIS MORNING THROUGH
THIS EVENING.
LATEST REGIONAL RADAR SHOWS THAT STORMS HAVE FIRED AS EXPECTED IN
NORTHEAST NEBRASKA ON THE NOSE OF A STRONG LLJ. THESE STORMS HAVE
MOVED INTO NW IOWA. A BIT FARTHER NORTH OVER SOUTH DAKOTA ANOTHER
AREA OF STORMS IS MOVE EWD. THESE ARE ASSOCIATED WITH A SHORT WAVE
MOVING ACROSS THE NRN PLAINS. SHORT RANGE MODELS MOVE THIS SHORT
WAVE SEWD TOWARD CHICAGO BY THIS AFTERNOON AT THE SAME TIME THE SFC
LOW IN SRN NEBRASKA IS MOVING ENEWD. HRRR SHOWS BOTH CLUSTERS OF
STORMS WEAKENING AS THEY MOVE EAST WITH THE IOWA CONVECTION MOVING
TO THE WRN CWA BY NOON OR SO AS MOSTLY SHOWERS.
CONVECTION REDEVELOPS OVER NW IOWA BY EARLY AFTERNOON AS STRONG
DYNAMICS TAKE SHAPE. SBCAPE AROUND 3K J/KG COUPLED WITH STRONG
MOISTURE CONVERGENCE...60-70KTS BULK SHEAR AND LIFT FROM THE
APPROACHING SHORT WAVE SHOULD RESULT IN STRONG TO SEVERE STORMS
DEVELOPING OVER ILLINOIS AND MOVING ESE TOWARD THE SRN CWA. A 50KT
MID LEVEL JET WILL PUSH THE STORMS EWD...PERHAPS AS A DERECHO. CAN/T
ARGUE TOO MUCH WITH THE POSITION OF THE DAY ONE SLIGHT AND MODERATE
RISK AREAS. THIS ISN/T A SLAM DUNK BY ANY MEANS BUT THE HIGHEST
THREAT FOR STRONG/SVR STORMS WILL BE SOUTH OF A MUSKEGON TO LANSING
LINE. LATEST NAM ALSO PUSHES THE WARM FRONT INTO THE SRN CWA THIS
AFTERNOON. SO...WITH THE WARM FRONT IN PLACE WE CAN/T RULE OUT A
TORNADO EITHER.
THE SVR THREAT WILL END THIS EVENING AS THE LOW MOVES BY TO THE
SOUTH AND QUIETER WEATHER WILL RETURN THURSDAY AND FRIDAY.
.LONG TERM...(FRIDAY NIGHT THROUGH TUESDAY)
ISSUED AT 330 AM EDT WED JUN 12 2013
UPPER RIDGING WILL EXTEND FROM THE GULF COAST NORTH INTO THE UPPER
MID WEST FRIDAY NIGHT. THE RIDGING WILL BE FLATTENED THROUGH THE
LONG TERM AS A SERIES OF SHORTWAVE/S CREST THE RIDGE AND MOVE
THROUGH THE GREAT LAKES REGION. THE FIRST OF WHICH MOVES INTO THE
AREA ON SATURDAY. THE SECOND AND MORE SUBSTANTIAL WAVE DIGS INTO THE
GREAT LAKES REGION SUNDAY INTO MONDAY.
AT THE SURFACE RIDGING WILL BE IN PLACE FRIDAY NIGHT AND BRING DRY
WEATHER. THE HIGH SLIPS EAST QUICKLY ON SATURDAY WHICH SHOULD ALLOW
CHANCES FOR SHOWERS AND STORMS DURING THE AFTERNOON AHEAD OF THE
UPPER SHORTWAVE. THE CHANCES WILL CONTINUE INTO SATURDAY NIGHT AS A
WAVE OF LOW PRESSURE SLIDES THROUGH THE AREA AT THE SURFACE.
SUNDAY INTO MONDAY CHANCES FOR SHOWERS AND STORMS WILL CONTINUE AS
THE SECOND MORE POTENT UPPER TROUGH DIGS INTO THE GREAT LAKES.
SURFACE FEATURES ARE BIT MORE HARD TO DISCERN IN THIS TIME FRAME AS
THE GFS IS FURTHER NORTH AND DEEPER WITH THE SURFACE WAVE. FOLLOWED
THE GFS CLOSER HERE AS IT MAKES MORE SENSE TO HAVE A DEEPER FARTHER
NORTH WAVE GIVEN THE UPPER PATTERN. WE LOOK TO DRY OUT MONDAY NIGHT
INTO TUESDAY AS HIGH PRESSURE BUILDS IN.
TEMPERATURES THROUGH THE PERIOD SHOULD BE SEASONABLE DESPITE THE
RIDGING DAMPENING OUT. HEIGHTS ARE STILL FAIRLY HIGH AND 850MB TEMPS
ARE FORECAST TO BE IN THE TEENS C. HIGHS SHOULD BE IN THE UPPER 70S
TO AROUND 80 EACH DAY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 747 AM EDT WED JUN 12 2013
MAIN CONCERN TODAY WILL BE THUNDERSTORM EVOLUTION...COVERAGE AND
SEVERITY. VFR CEILINGS ARE IN PLACE AT DAYBREAK...WITH SOME MVFR
VSBY/S IN FOG. THE EXPECTATION IS THE FOG WILL LIFT THIS
MORNING...GIVING WAY TO VFR CONDITIONS BY LATE MORNING. SOME
SCATTERED SHOWERS ARE EXPECTED THROUGH THE MORNING...BUT MOST WILL
BE LIGHT AND NOT IMPACT CONDITIONS MUCH.
THE FOCUS THIS AFTERNOON AND EVENING IS ON THUNDERSTORMS. A COUPLE
SCENARIOS ARE IN PLAY WITH STORMS SWEEPING IN OFF OF LAKE MICHIGAN
AS EARLY AS NOON TO 100PM. THEY WOULD MOVE THROUGH THE TAF SITES
THIS AFTERNOON WITH THE POTENTIAL FOR SIGNIFICANT WIND
GUSTS...OVER 50 KNOTS. A SECOND SCENARIO WOULD HAVE THE STORMS SWEEP
IN LATER THIS EVENING WITH A MAINLY DRY AFTERNOON. BOTH SCENARIOS
WILL HAVE SIGNIFICANT WIND POTENTIAL AS WELL AS HAIL. ANY STORMS
THAT DEVELOP TODAY COULD BE SEVERE. NORTHERLY WINDS WILL DEVELOP
TONIGHT IN THE WAKE OF THE STORMS WITH MVFR CEILINGS AND POSSIBLY
VSBY/S (FOG) DEVELOPING.
USED VCTS IS THIS MORNING/S TAFS GIVEN THE UNCERTAINTY. LATER
UPDATES WILL PROVIDE GREATER DETAIL.
&&
.MARINE...
ISSUED AT 330 AM EDT WED JUN 12 2013
FAIRLY LIGHT WINDS WILL CONTINUE OVER THE LAKE RESULTING IN LOW WAVE
HEIGHTS. PATCHY DENSE FOG IS POSSIBLE DUE TO HIGH DEWPOINTS OVER THE
COLDER WATER SFC. NORTH WINDS WILL DEVELOP THURSDAY AND A SMALL
CRAFT ADVISORY MAY BE NEEDED.
&&
.HYDROLOGY...
ISSUED AT 330 AM EDT WED JUN 12 2013
THE MAIN PERIOD OF CONCERN IS THIS AFTERNOON AND EVENING. HEAVY
RAINFALL WILL BE POSSIBLE ACROSS THE SRN HALF OF THE CWA DURING THIS
TIME. AN INCH TO TWO INCHES SEEMS PLAUSIBLE ESPECIALLY SOUTH OF
I-94. THIS MAY LEAD TO LOCALIZED FLOODING.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&
$$
SYNOPSIS...93
SHORT TERM...93
LONG TERM...DUKE
AVIATION...DUKE
HYDROLOGY...93
MARINE...93
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
630 AM CDT WED JUN 12 2013
.SHORT TERM...(THROUGH LATE THIS AFTERNOON)
ISSUED AT 337 AM CDT WED JUN 12 2013
MAIN CONCERN DEALS WITH POTENTIAL FOR SEVERE WEATHER THIS AFTERNOON
INTO THE EVENING HOURS OVER PARTS OF THE CWA IF THUNDERSTORMS ARE
ABLE TO DEVELOP. IF THUNDERSTORMS DO DEVELOP...THEN THEY WILL
LIKELY BE SEVERE...PARTICULARLY OVER NORTHEAST MISSOURI INTO CENTRAL
ILLINOIS WITH DAMAGING WIND GUSTS IN EXCESS OF 70 MPH...LARGE HAIL
AND ISOLATED TORNADOES.
EXPECT MAINLY DRY CONDITIONS THROUGH THE MORNING HOURS AS THE
THUNDERSTORM COMPLEX CURRENTLY OVER WESTERN IOWA STAYS NORTH OF THE
AREA PER THE RAP FORWARD PROPAGATION VECTORS. OBSERVED AND FORECAST
SOUNDINGS STILL SHOW A VERY PRONOUNCED WARM LAYER BETWEEN 900-650MB
THROUGH LATE AFTERNOON WHICH SHOULD LIMIT THUNDERSTORM DEVELOPMENT.
THEREAFTER...THE TAIL END OF THE TROUGH CURRENTLY OVER THE HIGH
PLAINS WILL REACH THE MISSISSIPPI RIVER WHICH WILL ACT TO WEAKEN
THIS WARM LAYER AS THE ATTENDANT COLD FRONT MOVES SOUTHEAST ACROSS
THE CWA. MOST MODEL SOUNDINGS STILL SHOW SOME CONVECTIVE INHIBITION
OR VERY NARROW POSITIVE CAPE UP TO 700MB WHICH MAY KEEP
THUNDERSTORMS NORTH AND EAST OF THE AREA. WITH THIS SAID...MID
LEVEL FORCING AND LOW LEVEL MOISTURE CONVERGENCE IS WORTH KEEPING
SCATTERED THUNDERSTORMS IN THE FORECAST LATE THIS AFTERNOON INTO THE
EVENING AS THE COLD FRONT MOVES ACROSS THE CWA. INSTABILITY AND
SHEAR PARAMETERS FAVOR SEVERE THUNDERSTORMS WITH LATE AFTERNOON
MLCAPES AROUND 3000 J/KG AND 0-6KM SHEAR OF 40-50KTS. RELATIVELY
DRY AIR BELOW 700MB FAVORS THE POTENTIAL FOR DAMAGING WINDS
GUSTS...AND THERE IS A LARGE AMOUNT OF CAPE BETWEEN -10 AND -30C
WHICH SUGGESTS THE POTENTIAL FOR LARGE HAIL. SHEAR IS LINEAR IN THE
LOWEST LEVELS...THOUGH 0-1KM SHEAR NEAR 25KTS SUGGESTS TORNADOES ARE
ALSO POSSIBLE.
DID NOT CHANGE FORECAST HIGHS TODAY AS CURRENT TEMPERATURES ARE IN
THE 70S AND THERE WILL BE DECENT MIXING UP TO 850MB TODAY WITH MORE
SUN THAN YESTERDAY.
BRITT
.LONG TERM...(TONIGHT THROUGH TUESDAY)
ISSUED AT 337 AM CDT WED JUN 12 2013
AFTERNOON/EVENING CONVECTION SHOULD BE EXITING THE AREA BY 06Z.
CANNOT RULE OUT A STRAY SHOWER OR STORM OUT AHEAD OF OR RIGHT ON THE
COLD FRONT AS IT PUSHES THROUGH EAST CENTRAL AND SOUTHEAST MISSOURI
AND SOUTHERN ILLINOIS. NORTHWEST FLOW WILL BRING COOLER AND DRIER
AIR WITH SURFACE DEWPOINTS DROPPING BACK INTO THE UPPER 50S AND
LOWER 60S. 850MB TEMPS ALSO DROP INTO THE LOW TO MID TEENS BEHIND
THE FRONT. MODELS HAVE BEEN CONSISTENTLY AMPLIFYING THE FLOW
THURSDAY INTO FRIDAY WITH A FULL LONGWAVE TROF OVER THE EAST COAST
AND THE UPPER LEVEL RIDGE BUILDING ACROSS THE GREAT PLAINS INTO THE
UPPER MIDWEST. THIS SHOULD KEEP THE LOW LEVEL RIDGE LOCKED IN
ACROSS THE MISSISSIPPI VALLEY AT LEAST THROUGH FRIDAY. SEASONABLY
COOL GUIDANCE TEMPS LOOK PRETTY REASONABLE WITH AFOREMENTIONED COOL
AND DRY RIDGE IN PLACE. THERE IS A SMALL CHANCE THAT INCREASING
WARM ADVECTION ON THE WESTERN PERIPHERY OF THE LOW LEVEL RIDGE MAY
PRODUCE ISOLATED SHOWERS OR STORMS FRIDAY OVER PARTS OF CENTRAL AND
NORTHEAST MISSOURI SO HAVE SOME SLIGHT CHANCE POPS IN THOSE AREAS.
THE WEEKEND IS LOOKING MORE AND MORE STORMY AS THE UPPER LEVEL RIDGE
BREAKS DOWN IN RESPONSE TO A SHORTWAVE WHICH IS PULLED NORTHEAST OUT
OF THE GULF OF MEXICO. THIS WAVE IS LIKELY TO HAVE QUITE A BIT OF
MOISTURE ASSOCIATED WITH IT. AM UNSURE WHAT THE POTENTIAL FOR
SEVERE WEATHER WILL BE AT THIS TIME...BUT IT DOES LOOK LIKE THERE
WILL BE THUNDERSTORMS ON AND OFF FROM SATURDAY AFTERNOON AT LEAST
THROUGH SUNDAY NIGHT OR MONDAY AND SOME LOCALLY HEAVY RAIN MAY BE
POSSIBLE. TUESDAY LOOKS DRIER AS THE WAVE MOVES EAST AND WEAK
RIDGING BUILDS BACK ACROSS THE MID MISSISSIPPI VALLEY. TEMPERATURES
THROUGH THE PERIOD LOOK TO BE NEAR NORMAL.
CARNEY
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 626 AM CDT WED JUN 12 2013
A COLD FRONT WILL MOVE SOUTHEAST ACROSS THE AREA LATE THIS AFTERNOON
INTO THIS EVENING. IF THUNDERSTORMS DO DEVELOP ALONG THE FRONT...
THEY WILL BE CAPABLE OF PRODUCING HAIL AND GUSTY WINDS...AS WELL
AS BRIEF MVFR/POSSIBLE IFR CONDITIONS. MOST LIKELY LOCATION FOR
THUNDERSTORMS WILL BE AT KUIN. OTHERWISE EXPECT DRY AND VFR
CONDITIONS WITH GUSTY SOUTHWEST WINDS WHICH COULD CAUSE CROSSWIND
PROBLEMS FOR SMALLER AIRCRAFT ON NORTHWEST-SOUTHEAST ORIENTED
RUNWAYS. MODEL GUIDANCE IS INDICATING THAT LOW MVFR/IFR CEILINGS
MAY DEVELOP LATE TONIGHT...THOUGH DO NOT HAVE ENOUGH CONFIDENCE TO
INCLUDE IN THIS SET OF TAFS.
SPECIFICS FOR KSTL...EXPECT DRY AND VFR CONDITIONS WITH GUSTY
SOUTHWEST WINDS LATE THIS MORNING AND AFTERNOON. THERE IS A CHANCE
OF THUNDERSTORMS BETWEEN 23-03Z...BUT CHANCE IS TOO LOW TO INCLUDE
IN THE TAF AT THIS POINT. MODEL GUIDANCE ALSO INDICATES THAT LOW
MVFR/IFR CEILINGS WILL MOVE INTO THE TERMINAL AFTER 09Z...THOUGH
CONFIDENCE IS NOT HIGH ENOUGH TO INCLUDE WITH THIS TAF ISSUANCE.
BRITT
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
631 AM CDT WED JUN 12 2013
.AVIATION...12Z TAFS FOR KOFK...KLNK AND KOMA.
VFR CONDITIONS ARE EXPECTED THROUGH THURSDAY MORNING. HIGH
PRESSURE BUILDING IN BEHIND AN EXITING LOW PRESSURE SYSTEM WILL
BRING GUSTY NORTHWEST WINDS OF 15 TO 25KT THROUGH THE DAY. THOSE
WINDS WILL SUBSIDE THIS EVENING. SCATTERED TO BROKEN CLOUDS NEAR
FL040 ARE LIKELY DURING THE AFTERNOON BUT SHOULD ALSO DISSIPATE AT
SUNSET.
DERGAN
&&
.PREV DISCUSSION... /ISSUED 242 AM CDT WED JUN 12 2013/
DISCUSSION...
LOW PRESSURE WAS LOCATED OVER SOUTH CENTRAL NEBRASKA AT 07Z
WITH A COLD FRONT TRAILING INTO WESTERN KANSAS AND A WARM FRONT
EXTENDING ACROSS SOUTHEAST NEBRASKA AND SOUTHWEST IOWA. CONVECTION
WAS ONGOING OVER EASTERN NEBRASKA INTO WEST CENTRAL AND NORTHWEST
IOWA.
LATEST HRRR MODEL TRACKS THE SURFACE LOW EAST TOWARD SOUTHWEST
IOWA THIS MORNING WITH THE COLD FRONT MOVING THROUGH THE AREA BY
18Z. CURRENT CONVECTION IS EXPECTED TO PUSH EAST OF THE AREA BY
THIS SAME TIME IN ADVANCE OF THE LOW AND NORTH OF THE WARM FRONT.
HIGH PRESSURE THEN BUILDS INTO THE PLAINS REGION THIS AFTERNOON
AND TONIGHT. AS THE HIGH MOVES EAST INTO THE MISSISSIPPI VALLEY
ON THURSDAY SOUTHERLY FLOW RETURNS TO THE PLAINS ALONG WITH A WARM
ADVECTION PATTERN AND THE CHANCE OF THUNDERSTORMS FOR THURSDAY
NIGHT INTO FRIDAY MORNING. AS ANOTHER STRONG UPPER WAVE MOVES INTO
THE NORTHERN PLAINS ON FRIDAY A COLD FRONT MOVES INTO THE AREA
AGAIN FRIDAY NIGHT WITH ANOTHER CHANCE OF STORMS FOR THE AREA.
EXTENDED MODELS STILL SHOW SOME POTENTIAL FOR ADDITIONAL STORMS
SATURDAY INTO SUNDAY. WITH THE UPPER PATTERN REMAINING STRONG AND
ACTIVE THROUGH MID WEEK PERIODS OF STORMS STILL INDICATED FOR THE
AREA DURING THIS TIME.
FOBERT
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
1111 AM EDT WED JUN 12 2013
.SYNOPSIS...
HOT TEMPERATURES ARE EXPECTED TODAY AND THURSDAY AS AN UPPER RIDGE
MOVES ACROSS THE REGION. A FEW THUNDERSTORMS MAY DEVELOP INLAND
LATE IN THE AFTERNOON. A RELATIVELY STRONG COLD FRONT WILL MOVE
ACROSS THE AREA THURSDAY NIGHT WITH A GOOD CHANCE OF SHOWERS AND
THUNDERSTORMS. DRY WEATHER IS EXPECTED INTO THE WEEKEND. A COLD
FRONT WILL REACH THE CAROLINAS EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1100 AM WEDNESDAY...HOT AND HUMID DAY ON TAP FOR THE AREA AS
SUMMER MAKES ITS FIRST STRONG FORAY INTO THE CAROLINAS. WV IMAGERY
THIS MORNING PAINTS THE PICTURE WITH LARGE SURFACE HIGH AND MID
LEVEL RIDGING ELONGATED WEST-TO-EAST ACROSS THE SOUTHERN TIER AND
OUT INTO THE ATLANTIC OCEAN. THIS IS A MODIFIED "RING OF FIRE"
SETUP...AND STRONG CONVECTION IS ANTICIPATED ACROSS THE OH VLY INTO
THE MID-ATLANTIC TODAY. THE BIG QUESTIONS FOR TODAY WILL BE: 1) HOW
HOT WILL IT GET AND 2) WILL THERE BE CONVECTION THIS EVENING.
AS FAR AS TEMPERATURES GO...AM EXPECTING THE HOTTEST DAY SINCE
SEPTEMBER 1, 2012. 12Z SOUNDING AT KCHS SHOWED 850MB TEMPS OF
20C...WHILE KMHX HAD 15C. THIS SHOWS THE LEVEL OF WARMTH POSSIBLE
TODAY...AS MID-LEVEL THERMAL RIDGE WILL BULGE NORTHWARD TODAY...AND
NAM BUFR SOUNDINGS SHOW 3-4C OF WARMING AT 850MB THROUGH TONIGHT.
THESE VERY WARM TEMPS COMBINED WITH AMPLE SOLAR INSOLATION AND SOME
DOWNSLOPE WARMING THANKS TO NW FLOW ABOVE 900MB...WILL ALLOW TEMPS
TO SOAR WELL INTO THE 90S TODAY. HAVE SIDED WITH THE HIGHER MAV
NUMBERS...WHICH SUGGESTS TEMPS RISING TO 92-97 TODAY...WITH UPPER
80S EVEN AT THE IMMEDIATE BEACHES. THESE TEMPS COMBINED WITH
DEWPOINTS IN THE UPPER 60S...LOW 70S AT THE COAST...WILL DRIVE HEAT
INDICIES TO AROUND 100 DEGREES...AND A HEAT RELATED SPS REMAINS IN
EFFECT FOR TODAY.
FOR CONVECTION...THE SITUATION IS QUITE TRICKY. HIGH-RES GUIDANCE IS
SHOWING MANY DIFFERENT SOLUTIONS...BUT THERE ARE REALLY TWO CAMPS.
THE NAM/ARW/NMM SUGGESTS REMNANT MCS CONVECTION RIDING DOWN TO THE
SOUTH AND CLIPPING THE WESTERN PORTIONS OF THE CWA. THE
HRRR/WRF/SREF ARE MUCH LESS AGGRESSIVE...WITH THE HRRR SHOWING NO
DEVELOPMENT AT ALL. SO...WHICH SOLUTION WILL BE RIGHT? WHILE A FEW
STORMS HAVE ALREADY FIRED ACROSS THE MTNS OF VA/WV...THIS COULD BE
AN INDICATOR THAT MORE DEVELOPMENT WILL OCCUR THIS AFTN IN A
WELL-HEATED ENVIRONMENT. IF THIS OCCURS...IT WOULD TEND TO RIDE
SOUTH AROUND THE RIDGE TOWARDS THE WESTERN CWA. AT THE SAME TIME
HOWEVER...MID LEVEL RIDGING AND THERMAL ADVECTION WILL WORK AGAINST
THIS...AS SUBSIDENCE AND WEAKENING MID-LEVEL LAPSE RATES SQUELCH
ADVANCING CONVECTION. HAVE CONTINUED SCHC FOR THE WESTERN HALF OF
THE CWA...BUT IT WILL LIKELY BE A DAY WHERE UPDATES NEED TO BE MADE
IN A NOWCAST MANNER AS CONVECTION TRENDS BECOME DETERMINED.
MINS TONIGHT WILL REMAIN WELL ABOVE NORMAL WITH CONTINUED SW WINDS
AND WAA...FALLING ONLY INTO THE MID 70S.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 3 AM WEDNESDAY...THE HOTTEST DAY OF THE YEAR SO FAR
EXPECTED ON THURSDAY. TEMPS WILL SOAR INTO THE MID 90S AS STRONG
WESTERLY DOWNSLOPE FLOW DEVELOPS THROUGH THE LOW LEVELS OF THE
ATMOSPHERE AND RIDGE EXTENDS INTO THE CAROLINAS THROUGH THE MID
TO UPPER LEVELS. MODELS SHOW W WINDS UP TO 30 TO 40 KT JUST ABOVE
THE SURFACE WITH H5 HEIGHTS UP TO 589 DEM. AT THE SAME TIME DEW
POINT TEMPS WILL REMAIN AROUND 70 DEGREES. TEMPS LOOKS LIKE THEY
WILL BE WARMEST ACROSS INLAND AREAS WITH PEAK ACROSS NORTHEAST
SOUTH CAROLINA. THE DEWPOINT TEMPS WILL BE HIGHEST THROUGH THE
MORNING HOURS BUT ONCE MIXING OCCURS READINGS WILL DROP INTO THE
60S INLAND WITH GREATEST VALUES ACROSS GEORGETOWN AND HORRY
COUNTIES IN THE AFTERNOON. THESE TWO COUNTIES WILL MOST LIKELY
SURPASS HEAT ADVISORY CRITERIA WITH APPARENT TEMPERATURES UP ABOVE
105 F...WHILE THE REST OF SOUTH CAROLINA ZONES WILL BE CLOSE.
SOUTHEAST NORTH CAROLINA WILL FEEL CLOSER TO 100 DEGREES F.
AFTER SUCH A WARM AND DRY DAY ON THURSDAY...A COLD FRONT WILL
APPROACH FROM THE NORTHWEST. IT LOOKS LIKE THE BEST DYNAMICS WILL
COME TOGETHER IN THE EVENING HOURS AS A SHORTWAVE PUSHES THE FRONT
EAST ACROSS THE AREA. THE BEST SHORTWAVE ENERGY WILL REMAIN TO OUR
NORTH BUT STILL IMPRESSIVE LIFT AND MOISTURE OVER LOCAL AREA TO
PRODUCE POTENTIAL FOR SEVERE THUNDERSTORMS. CAPE VALUES UP TO 2-3K
J/KG WITH STEEP MID LEVEL LAPSE RATES WILL SUPPORT POTENTIAL FOR
STRONG TO SEVERE STORMS. THE STRONG STEERING FLOW WILL DRIVE
THESE STORMS RAPIDLY THROUGH THE AREA AND OFF THE COAST THROUGH
THE EVENING. THE ONE INHIBITING FACTOR WILL BE THE LOSS OF SURFACE
HEATING ALTHOUGH WITH TEMPS WELL INTO THE 90S IN THE
AFTN...READINGS WILL STILL BE HIGH THROUGH THE EVENING HOURS. ONE
OTHER LIMITING FACTOR WILL BE THE LACK OF GREAT MOISTURE RETURN
FROM THE GULF. THEREFORE EXPECT MOST ACTIVITY TO BE FOCUSED ALONG
AND JUST AHEAD OF FRONTAL BOUNDARY MOVING THROUGH RAPIDLY THROUGH
LATE EVENING. AFTER MIDNIGHT MOST OF THE ACTIVITY WILL MAINLY BE
CONFINED TO COASTAL COUNTIES OR OFF SHORE AS COLD FRONT MOVES
THROUGH. RAPID DRYING WILL FOLLOW WITH PCP WATER VALUES DROPPING
FROM 1.9 INCHES JUST AHEAD AND ALONG COLD FRONT DOWN TO LESS THAN
AN INCH BY DAYBREAK FRIDAY.
DEEP DRY NORTHERLY FLOW WILL KEEP TEMPS IN THE MID 80S FOR HIGHS
ON FRIDAY. THIS COMBINED WITH DEWPOINT TEMPS DOWN A GOOD 10
DEGREES WILL MAKE IT FEEL RELATIVELY COOLER ON FRIDAY. MAY SEE
SOME CU BUILD UP WITH RESIDUAL MOISTURE FROM RAINFALL THE NIGHT
BEFORE BUT OVERALL WILL SEE PLENTY OF SUNSHINE. WINDS WILL WEAKEN
THROUGH THE DAY ON FRI AS HIGH PRESSURE MOVES INTO THE CAROLINAS.
EXPECT DECENT RADIATIONAL COOLING FRI NIGHT WITH TEMPS COOLING
DOWN INTO THE MID 60S.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
AS OF 3 AM WEDNESDAY...HIGH PRESSURE WILL BUILD DOWN OVER THE
CAROLINAS AS MID TO UPPER RIDGE MOVES IN FROM THE WEST. A LIGHT
NORTHERLY FLOW ON FRONT END OF HIGH WILL LIGHTEN AND BECOME MORE
VARIABLE ON SATURDAY AS THE CENTER SHIFTS CLOSER OVERHEAD. A LIGHT
RETURN FLOW WILL SET UP SAT NIGHT INTO SUNDAY AS THE HIGH SHIFTS
OFF SHORE. OVERALL EXPECT SEASONABLE WEATHER WITH PLENTY OF
SUNSHINE AND TEMPS RIGHT AROUND NORMAL...IN THE MID 80S DURING THE
DAY AND MID 60S OVERNIGHT. SFC DEWPOINTS INITIALLY WILL BE LOWER
BUT WILL CREEP UP BY THE END OF THE WEEKEND INTO EARLY NEXT WEEK
PRODUCING SLIGHTLY MORE HUMID WEATHER. PCP WATER VALUES WILL
REMAIN CLOSER TO AN INCH THROUGH THE WEEKEND INTO EARLY NEXT WEEK.
BY LATE MONDAY INTO TUESDAY THE RIDGE ALOFT BEGINS TO BREAK DOWN
AS A SHORTWAVE DIGS DOWN FROM THE GREAT LAKES AND PUSHES A COLD
FRONT EAST BY TUESDAY. DEEPER LAYER MOISTURE WILL SET UP AHEAD OF
THE FRONT WITH PCP WATER VALUES INCREASING UP TO 1.75 INCHES IN A
DEEP SOUTHWESTERLY FLOW. EXPECT MORE ACTIVE WEATHER BY TUES
AFTERNOON AS COLD FRONT APPROACHES. RETURN FLOW NEXT WEEK WILL
LEAD TO TEMPS INCREASING A FEW DEGREES ABOVE CLIMO MON AND TUE.
&&
.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
AS OF 12Z...A HOT DAY IN STORE WITH LIGHT SOUTHWEST WINDS. ANY FOG
AT THE START OF TAF TIME WILL QUICKLY MIX OUT BEFORE 13Z. A THERMAL
TROUGH WILL SET UP TODAY ON THE LEE SIDE OF THE APPALACHIANS. AN
ISOLATED THUNDERSTORM MAY DROP SOUTHEAST AROUND MAX HEATING...BUT
WILL LEAVE VCTS OUT OF THE WESTERN TAFS FOR NOW. TONIGHT...VFR
CONDITIONS UNTIL 08-09Z AS ANOTHER ROUND OF SHALLOW FOG IS EXPECTED.
NEARLY CALM WINDS.
EXTENDED OUTLOOK...ISOLATED SHOWERS/THUNDERSTORMS WITH TEMPO PERIODS
OF MVFR/IFR POSSIBLE THURSDAY EVENING INTO FRIDAY MORNING. OTHERWISE
VFR.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 1100 AM WEDNESDAY...CONTINUED SW WINDS AROUND OFFSHORE HIGH
PRESSURE WILL KEEP SW WINDS AND A SW WIND CHOP PREDOMINANT OVER THE
WATERS. SEAS CURRENTLY 2-4 FT WILL REMAIN STATUS QUO THROUGH THE
PERIOD...WITH SW WINDS OF 10-15 KTS PERSISTENT. THE EXCEPTION TO
THIS WILL BE WITHIN THE INNER FEW NM IN THE SEA BREEZE
BOUNDARY...WITH A SLIGHTLY BACKING TO SOUTH WILL OCCUR AS WELL AS AN
INCREASE IN SPEEDS...WITH GUSTS UP TO 20 KTS. SEAS WILL REMAIN 2-4
FT IN THIS ZONE...BUT WILL BECOME MORE CHOPPY THANKS TO SHORTER
PERIODS.
SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 3 AM WEDNESDAY...WINDS WILL INCREASE OUT OF THE SW THROUGH
THURSDAY AS COLD FRONT APPROACHES FROM THE WEST. WINDS WILL START
OUT AROUND 15 KTS BUT WILL REACH UP TO 20 TO 25 KTS THURS EVENING
JUST AHEAD OF THE COLD FRONT. THESE WINDS WILL HELP DRIVE SEAS UP
FROM 2 TO 4 FT EARLY THURS UP TO 4 TO 6 FT THURS EVENING REACHING
SMALL CRAFT CRITERIA LATE THURS AFTN INTO THURSDAY EVENING.
ONCE COLD FRONT CROSSES THE WATERS AFTER MIDNIGHT THURS NIGHT INTO
EARLY FRIDAY...THE WINDS WILL VEER AROUND TO THE NORTHWEST. SEAS
WILL DROP DOWN BELOW SCA QUICKLY OVERNIGHT AND WILL CONTINUE TO
SUBSIDE IN A WEAKENING OFF SHORE FLOW THROUGH FRIDAY. SEAS WILL BE
2 TO 3 FT MOST WATERS BY FRI EVENING.
LONG TERM /SATURDAY THROUGH SUNDAY/...
AS OF 3 AM WEDNESDAY...
HIGH PRESSURE WILL SHIFT CLOSER OVERHEAD ON SATURDAY AND THEN WILL
SHIFT FURTHER OFF THE COAST BY SATURDAY NIGHT INTO SUNDAY.
THEREFORE WINDS WILL VEER AROUND FROM NORTHERLY ON SATURDAY TO
SOUTHERLY BY SUNDAY REMAINING AROUND 10 KT OR LESS. WINDS WILL
SPIKE UP IN SEA BREEZE EACH AFTERNOON IN NEAR SHORE WATERS. SEAS
WILL REMAIN 3 FT OR LESS THROUGH MUCH OF THE WEEKEND.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...JDW
SHORT TERM...RGZ
LONG TERM...RGZ
AVIATION...43
AREA FORECAST DISCUSSION
NWS RALEIGH NC
1100 AM EDT WED JUN 12 2013
.SYNOPSIS...
A DEEPENING LOW PRESSURE SYSTEM AND ASSOCIATED COLD FRONT WILL
PROGRESS FROM THE CENTRAL PLAINS INTO THE OHIO VALLEY TONIGHT...THEN
TRACK EAST THROUGH THE MID ATLANTIC AND CAROLINAS ON THURSDAY. DRY
HIGH PRESSURE WILL BUILD INTO THE REGION IN THE WAKE OF THE COLD
FRONT THURSDAY NIGHT AND FRIDAY.
&&
.NEAR TERM /TODAY AND TONIGHT/...
AS OF 1100 AM WEDNESDAY...
AN UPPER LEVEL RIDGE CENTERED OVER THE SOUTHERN PLAINS WILL
STRENGTHEN SOMEWHAT TODAY WITH MINOR HEIGHT RISES ACROSS THE MID
ATLANTIC. SMALL AMPLITUDE DISTURBANCES IN NW FLOW ALOFT ARE
EXPECTED TO TRACK SOUTHEAST INTO THE CAROLINAS THIS AFTERNOON
THROUGH TONIGHT WHILE A MUCH MORE POTENT SHORTWAVE CENTERED ATOP THE
RIDGE IN THE NORTHERN PLAINS THIS MORNING WILL TRACK INTO THE TN/OH
VALLEY TONIGHT. A WEAK SURFACE TROUGH ACROSS CENTRAL NC WILL PERSIST
ACROSS WESTERN/CENTRAL NC WITH A LIGHT SW SURFACE WIND BECOMING MORE
WESTERLY THIS AFTERNOON.
WE HAVE BEEN MONITORING A REGION OF ISOLATED CONVECTION IN THE
CENTRAL APPALACHIANS THAT DEVELOPED OVERNIGHT. THE FACT THIS
DEVELOPED DURING AN ATYPICAL TIME OF DAY SUGGEST THAT SOME MESOSCALE
FORCING IS LIKELY DRIVING THIS AND IT APPEARS TO BE DEVELOPING IN A
REGION OF WARM ADVECTION AND ENHANCED MID LEVEL FLOW. CONVECTION
ALLOWING MODELS PROVIDE A VARIETY OF SOLUTIONS WITH THIS CONVECTION:
THE 00 UTC ARW/NMM HI RES WINDOWS SUGGEST SOME OF THE CONVECTION
WILL PERSIST AND GROW INTO A CLUSTER OF CONVECTION AROUND MIDDAY AND
SWEEP SOUTHEAST ACROSS THE PIEDMONT WHILE THE HRRR SUGGESTS THAT
ONGOING CONVECTION WILL WEAKEN WITH LITTLE ADDITIONAL REDEVELOPMENT
LIKELY. WITH RECENT RADAR TRENDS SUGGESTING A DECREASE IN
INTENSITY/COVERAGE OF THE CONVECTION AND THE PERSISTENCE OF A MID
LEVEL CAPPING INVERSION...HAVE OPTED TO REMOVE SLIGHT CHANCE POPS IN
THE EAST THIS AFTERNOON AND HIGHLIGHT THE FAR WEST DURING THE EARLY
TO MID AFTERNOON PERIOD FOR SLIGHT CHC POPS...ESPECIALLY ALONG THE
YADKIN RIVER.
CONVECTIVE DEBRIS CLOUDS ARE ALREADY SPREADING ACROSS THE WESTERN
PIEDMONT AND WILL SWEEP INTO THE EASTERN PIEDMONT AND SANDHILLS THIS
AFTERNOON. THE THICKER CLOUDS CLOSE TO THE YADKIN SHOULD BE
SUFFICIENT ENOUGH TO RETARD TEMPERATURES A DEGREE OR TWO. BUT WE
STILL EXPECT HIGHS TO RANGE IN THE 88 TO 95 RANGE TODAY. EXPECT LOWS
OVERNIGHT IN THE 69 TO 73 RANGE. -BLAES/VINCENT
&&
.SHORT TERM /THURSDAY AND THURSDAY NIGHT/...
AS OF 300 AM WEDNESDAY...
...SEVERE WEATHER EXPECTED THURSDAY AFTERNOON AND EVENING...
THURSDAY AND THURSDAY NIGHT:
AN UNSEASONABLY AMPLIFIED PATTERN WILL PERSIST ON THU...
CHARACTERIZED BY A STRONG UPPER LEVEL RIDGE OVER THE CENTRAL CONUS
AND NW FLOW ALOFT DOWNSTREAM ACROSS THE TN/OH VALLEY AND
MID-ATLANTIC. ROBUST SHORTWAVE ENERGY (AND AN ATTENDANT SFC LOW) IN
THE OH VALLEY THU MORNING WILL TRACK EAST ACROSS THE MID-ATLANTIC
THU AFTERNOON AND EVENING. MODERATE INSTABILITY (1500-2500 J/KG
MLCAPE) IS EXPECTED ACROSS CENTRAL NC...IN ASSOCIATION WITH STEEP
(6.5-7.5 C/KM) MID-LEVEL LAPSE RATES AND SEASONABLE BOUNDARY LAYER
MOISTURE. STRENGTHENING WESTERLY FLOW ALOFT IN ADVANCE OF THE
SHORTWAVE WILL RESULT IN 0-6 KM SHEAR ON THE ORDER OF 25-40 KT
(STRONGEST NORTH)...SUFFICIENT FOR ORGANIZED CONVECTION...ESPECIALLY
IN THE PRESENCE OF MODERATE INSTABILITY AND STEEP MID-LEVEL LAPSE
RATES.
SOME UNCERTAINTY PERSISTS WITH REGARD TO THE SPECIFICS OF THIS
SYSTEM GIVEN SMALL VARIANCES IN TIMING AND ONGOING CONVECTION /MCS
ACTIVITY/ EXPECTED TO TRACK INTO THE APPALACHIANS THU MORNING. GIVEN
EXCELLENT SYNOPTIC FORCING...MODERATE DESTABILIZATION AND FAVORABLE
DEEP-LAYER SHEAR...A SIGNIFICANT SEVERE WEATHER EPISODE IS EXPECTED
ACROSS THE REGION THU AFTERNOON AND EVENING. FROM A PATTERN
RECOGNITION STANDPOINT...THE EXPECTED ENVIRONMENT IN CENTRAL NC
WOULD PRIMARILY SUPPORT AN ENHANCED THREAT OF DAMAGING WINDS GIVEN
UNIDIRECTIONAL DEEP-LAYER SHEAR...SPEEDY MID-LEVEL FLOW AND STRONG
EVAP COOLING POTENTIAL ASSOC/W THE MODIFIED EML IN PLACE AND
INVERTED-V PROFILES IN THE BOUNDARY LAYER. W/REGARD TO CONVECTIVE
MODE...EXPECT A RELATIVELY NARROW WINDOW FOR ANY DISCRETE CONVECTION
PRIOR TO RAPID UPSCALE GROWTH INTO AN MCS GIVEN HIGH DCAPE /STRONG
COLD POOLS/ AND MODERATE INSTABILITY. THE LATEST GUIDANCE SUGGESTS
THAT THE TORNADO THREAT WOULD LIKELY REMAIN WELL TO THE NORTH (I.E.
NORTHERN VA/MD/PA/NJ) AND OTHER PORTIONS OF THE MID-ATLANTIC
COAST...IN CLOSER VICINITY TO THE SFC LOW TRACK AND WARM FRONT AND
BETTER LOW-LEVEL DIRECTIONAL SHEAR. WITH EXPECTED MCS ACTIVITY AND
OUTFLOW PROGRESSING INTO THE MOUNTAINS THU MORNING AND A POTENTIAL
FOR HINDERED DESTABILIZATION MID/LATE THU MORNING INTO EARLY THU
AFTERNOON IN THE FAR W/NW PIEDMONT...HAVE DECREASED PRECIP CHANCES
TO 40% IN THAT AREA...WITH PRECIP CHANCES AT 50% IN VICINITY OF THE
HWY 1 CORRIDOR AND 60-70% EAST OF INTERSTATE 95. EXPECT THE BEST
SEVERE THREAT EAST OF HWY 1 AT THIS TIME. HIGHS LOWER TO MID
90S...WARMEST EAST...THOUGH CONFIDENCE IS LOWER THAN NORMAL GIVEN
UNCERTAINTY W/REGARD TO MCS ACTIVITY/CLOUD COVER THAT MAY PROGRESS
INTO WESTERN PORTIONS OF THE STATE IN THE MORNING. EXPECT LOWS THU
NIGHT IN THE MID TO UPPER 60S IN THE WAKE OF A COLD FRONTAL PASSAGE
AS THE SHORTWAVE AND ATTENDANT SFC LOW TRACK OFFSHORE THE
MID-ATLANTIC. -VINCENT
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
AS OF 300 AM WEDNESDAY...
FRIDAY AND FRIDAY NIGHT...THE LONGWAVE TROUGH MOVES EAST
FRIDAY...WITH AMPLE NVA IN THE MID-LEVELS TAKING PLACE FRIDAY NIGHT.
THE MEAN AIR MASS IS DRY...WITH A SLIGHT INCREASE IN OVERALL
MOISTURE TOWARD THE NORTHEAST PART OF THE STATE...INCLUDING THE
NORTHERN COASTAL PLAIN...CLOSER TO THE DEPARTING MID-LEVEL LOW. THE
GFS FORECASTS LINGERING...HIGHER PRECIPITABLE WATER VALUES NEAR AN
INCH TOWARD KIXA FRIDAY AFTERNOON...ALTHOUGH GFS BUFR SOUNDINGS AS
WELL AS NAM BUFR SOUNDINGS ARE STABLE AND CAPPED AROUND 700MB.
INTERESTINGLY BUT NOT TERRIBLY SURPRISING GIVEN THE STRENGTH OF THE
DEPARTING UPPER LOW...THE NAM AND GFS PRODUCE MEAGER...JUST
NOTICEABLE QPF MAINLY JUST EAST OF CENTRAL NORTH CAROLINA OVER THE
NORTHEAST PART OF THE STATE DURING FRIDAY AFTERNOON. SIMILAR
SCENARIOS HAVE OCCURRED IN THE RECENT PAST...BEHIND STRONG MID-LEVEL
SYSTEMS WHERE ENOUGH MOISTURE LINGERS TO RESULT IN ISOLATED SHOWERS
OR SPRINKLES SKIRTING OR MOVING INTO CENTRAL NORTH CAROLINA FROM THE
NORTHEAST. ON FRIDAY...WHILE A SPRINKLE MAY OCCUR LATE IN THE DAY
TOWARD KIXA...THE GFS FORECAST COMBINATION OF BEST 850MB AND 700MB
MOISTURE RESIDES JUST EAST OF CENTRAL NORTH CAROLINA BETWEEN 18Z
FRIDAY AND 00Z SATURDAY. AS A RESULT...WILL KEEP THIS FORECAST
DRY...SHOWING A RELATIVELY HIGHER AMOUNT OF CLOUDS IN THE AREA
DURING THE AFTERNOON THROUGH THE EVENING MAINLY FROM WILSON NORTH.
1000-850MB THICKNESSES AND BIAS CORRECTED TEMPERATURE GUIDANCE ALL
FAVOR HIGHS NEAR THE COOLER MET GUIDANCE FOR FRIDAY...AND BUFR
SOUNDINGS SHOW THERE MAY BE ENOUGH HIGH-BASED CU/SC FOR HIGHS TO BE
TEMPERED SOMEWHAT FROM THE WARMER MAV VALUES. OVERNIGHT LOWS 57 TO
62. EXPECT A FEW WIND GUSTS IN THE UPPER TEENS TO POSSIBLY LOWER 20S
KNOTS FRIDAY WITH INITIAL MIXING IN THE TIGHT GRADIENT BEHIND THE
DEPARTING LOW.
FOR THE PERIOD SATURDAY THROUGH TUESDAY...THE FORECAST FOR SATURDAY
REMAINS DRY AS A STABLE AND DRY AIR MASS UNDER HIGH PRESSURE IS
ANTICIPATED. AS THE WEEKEND ENDS AND WE APPROACH THE BEGINNING OF
THE NEXT WORK WEEK...GUIDANCE IS CONSISTENT IN PUSHING MODESTLY
STRONG MID-LEVEL SHORTWAVES ATOP THE RIDGE TO OUR WEST...EVENTUALLY
FLATTENING THAT UPPER RIDGE. THE CENTER OF SURFACE HIGH PRESSURE
MOVES OFF TO THE EAST OF CENTRAL NORTH CAROLINA BY SUNDAY
AFTERNOON...BRINGING MORE MOISTURE INTO CENTRAL NORTH CAROLINA.
BASED ON THE CONSENSUS OF THE LATEST GFS AND THE 12Z ECMWF...THE
APPROACH OF THE NEXT SURFACE FRONT WILL BE AT LEAST LATE TUESDAY...
WITH THE TYPICAL PIEDMONT TROUGH IN PLACE FOR SUNDAY INTO MONDAY.
WHILE THERE IS A NOTICEABLE INCREASE IN 850MB THETA-E AIR SUNDAY AS
PRECIPITABLE WATER VALUES RISE FROM UNDER AN INCH SATURDAY TO CLOSE
TO 1.5 INCHES ON THE GFS...AND THERE IS A SLIGHT STEEPENING OF THE
MID-LEVEL LAPSE RATES...GFS BUFR SOUNDINGS ARE STILL CAPPED TO DEEP
CONVECTION SUNDAY AFTERNOON. THERE IS A LITTLE CONCERN ABOUT
UPSTREAM DEVELOPMENT MOVING INTO THE REGION...BUT THE GFS THICKNESS
PROFILE WOULD SUGGEST ANY SUCH DEVELOPMENT WOULD TEND TO TRACK WELL
NORTH AND NORTHEAST OF THE AREA. IF ANYTHING DEVELOPS AT ALL
SUNDAY...IT IS CURRENTLY EXPECTED TO BE VERY ISOLATED. AS HEIGHTS
ALOFT CONTINUE TO FALL...AND LAPSE RATES AT LEAST ON THE GFS STEEPEN
EVER SO SLIGHTLY MONDAY COMPARED TO SUNDAY AS MOISTURE CONTINUES TO
INCREASE...ISOLATED TO WIDELY SCATTERED THUNDERSTORMS ARE POSSIBLE.
THE GFS BUFR SOUNDINGS ARE STILL WEAKLY CAPPED MONDAY AROUND 750MB...
AND THE COARSE 12Z ECMWF SOUNDINGS ACTUALLY ARE MORE STABLE MONDAY
THAN SUNDAY...SO WILL KEEP CHANCES FOR PRECIPITATION SLIGHT AT THIS
TIME...AND LOWEST IN THAT RANGE OVER THE SANDHILLS AND SOUTHERN
COASTAL PLAIN. BY TUESDAY...WITH THE SLOW APPROACH OF THE FRONT...
AND A CONTINUED INCREASE IN MOISTURE AND COOLING ALOFT...AT LEAST
SCATTERED SHOWERS AND THUNDERSTORMS ARE EXPECTED. OVERNIGHT LOWS
WILL GRADUALLY RISE FROM THE LOWER TO MID 60S SATURDAY NIGHT TO 69
TO 74 BY MONDAY NIGHT. AFTER HIGHS SATURDAY CLOSE TO 1000-850MB
THICKNESSES IN THE LOWER TO MID 80S...FORECAST HIGHS WILL BE IN THE
MID 80S TO AROUND 90...WARMEST MONDAY WITH THIS FORECAST. ONE
POSSIBLE ALTERNATIVE IS THAT SUNDAY ACTUALLY ENDS UP WARMER THAN
MONDAY WHEN THE AIR IS A LITTLE DRIER AS THE SOUTHWEST SURFACE
FLOW INITIALLY BECOMES MORE ENTRENCHED. FOR THAT DAY...LEANED ON THE
HIGH SIDE OF THE AVAILABLE GUIDANCE SUITE. -DJF
&&
.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
AS OF 645 AM WEDNESDAY...
24-HR TAF PERIOD:
VFR CONDITIONS WILL PREVAIL THROUGH THE TAF PERIOD. THE ONLY
POSSIBLE EXCEPTION WILL BE A SMALL CHANCE FOR ISOLATED SHOWERS AND
THUNDERSTORMS...BETWEEN 12-18Z AT THE INT/GSO TERMINALS AND PERHAPS
AT ANY TERMINAL THIS AFTERNOON...THOUGH THE RELATIVE BEST CHANCE
WILL REMAIN AT THE INT/GSO TERMINALS. CALM OR LIGHT/VARIABLE WINDS
THIS MORNING WILL BECOME WEST OR SOUTHWEST AT 7-13 KT THIS
AFTERNOON...REMAINING SOUTHWEST AT 5-10 KT TONIGHT AS A DEEPENING
LOW PRESSURE SYSTEM TRACKS INTO THE OH VALLEY.
LOOKING AHEAD:
ADVERSE AVIATION CONDITIONS IN THE FORM OF SCATTERED TO WIDESPREAD
SHOWERS AND THUNDERSTORMS ARE EXPECTED DURING THE DAY THURSDAY. ANY
THUNDERSTORMS THAT DEVELOP WILL BE CAPABLE OF PRODUCING DAMAGING SFC
WIND GUSTS IN EXCESS OF 50 KNOTS. AT THIS TIME...THE BEST CHANCE FOR
AFTERNOON CONVECTION AND SEVERE WEATHER WILL BE AT THE RDU/FAY/RWI
TERMINALS. ASIDE FROM CONVECTION...EXPECT BREEZY WEST/SOUTHWEST
WINDS THURSDAY AFTERNOON...SUSTAINED AT 15-20 KT WITH GUSTS UP TO
25-30 KT. WINDS WILL SHIFT TO THE NORTHWEST AT 10-15 KT IN THE WAKE
OF A COLD FRONTAL PASSAGE THURSDAY EVENING INTO THURSDAY NIGHT.
EXPECT DRY/VFR CONDITIONS TO PREVAIL IN THE WAKE OF THE FRONT FRIDAY
THROUGH THE WEEKEND. -VINCENT
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...VINCENT
NEAR TERM...BLAES/VINCENT
SHORT TERM...VINCENT
LONG TERM...DJF
AVIATION...VINCENT
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
1000 AM EDT WED JUN 12 2013
.SYNOPSIS...
LOW PRESSURE WILL MOVE ALONG A FRONT STALLED OVER THE AREA TONIGHT
AND THURSDAY MORNING. HIGH PRESSURE WILL SLIDE SOUTHEAST THROUGH THE
GREAT LAKES FRIDAY THROUGH SATURDAY AND TO THE CAROLINA COAST
SUNDAY. ANOTHER LOW WILL MOVE EAST ACROSS THE LAKES SUNDAY AND
MONDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
LATEST SATELLITE SHOWS A LOT OF DEBRIS CLOUDS MOVING EAST INTO THE
FORECAST AREA THIS MORNING. SO FAR...MODELS ARE HINTING AT THIS
CLOUD MASS ERODING FROM THE SOUTH AS TIME GOES ON. SO...WE SHOULD
HAVE A FAIR AMOUNT OF SUNSHINE RETURN THIS AFTERNOON TO HELP WITH
CONVECTIVE INITIATION FOR THE AFTERNOON INTO THE EVENING HOURS.
IT LOOKS LIKE THE BRUNT OF THE STORMS WILL DEVELOP AND AFFECT THE
AREA LATE THIS AFTERNOON INTO THE EVENING HOURS. BEST UPPER LEVEL
POSITIVE VORTICITY ADVECTION AND VORTICITY MAXIMUM SCOOTS ACROSS
LAKE ERIE AROUND 21Z THIS AFTERNOON AND THEN THE NEXT MORE POTENT
UPPER LEVEL VORTICITY MAXIMUM ARRIVES LATE THIS EVENING INTO
TONIGHT. PRECIPITABLE WATER VALUES ARE NOW APPROACHING 2 INCHES
AND WITH DEEP WARM LAYER...SIGNIFICANT RAINFALL IS
EXPECTED...ESPECIALLY IN TRAINING THUNDERSTORMS.
SEVERE WEATHER THREAT IS STILL LIKELY WITH WIND...HAIL AND
POSSIBLY TORNADOES BEING THE THREATS FOR THIS AFTERNOON INTO
TONIGHT. WILL CONTINUE TO MONITOR THE SITUATION AS IT DEVELOPS.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY NIGHT/...
THIS LOOKS TO BE ONE OF THE BEST SETUPS FOR A CONVECTIVE COMPLEX TO
WORK ACROSS THE CWA THAT WE`VE SEEN IN A WHILE. NOT SAYING THERE
WILL BE A DERECHO BUT THE POSSIBILITY IS THERE. TRACK OF THE CORE OF
THE CONVECTION HAS BEEN CONSISTENT FOR SEVERAL DAYS SO WILL STAY
WITH POPS 90 PERCENT OR BETTER AT SOME POINT TONIGHT INTO THU
MORNING FOR THE WHOLE CWA.
WITH P/W`S RUNNING CLOSE TO 2 INCHES FOR MOST OF THE AREA SEE NO
REASON NOT TO HAVE A FLOOD WATCH GOING. ENOUGH QPF STILL SHOWN FOR
THU MORNING TO SLOW POP DRAW DOWN SOME.
QUESTION WHETHER THINGS WILL BE ABLE TO RECOVER FROM MORNING PRECIP
AND CLOUDS TO ALLOW AIRMASS TO DESTABILIZE ENOUGH FOR SOME WIDELY
SCT AFTERNOON CONVECTION TO DEVELOP. GFS HAS BEEN CONSISTENTLY
TRYING TO REDEVELOP SOME SHRA OVER THE WEST THU AFTERNOON AS A
RESULT OF FORCING FROM PRESENCE OF UPPER TROUGH. COOLER FLOW OUT OF
THE NORTH BEHIND THE LOW THU AFTERNOON...ALONG WITH GENERAL
SUBSIDENCE AND DRIER AIR WOULD SEEM TO MAKE IT FAIRLY TOUGH TO ALLOW
FOR MUCH CONVECTION TO DEVELOP. GUIDANCE POPS FOR 18Z THRU 00Z THU
EVE VERY LOW AND THIS SEEM TO MAKE SENSE SO WILL LOWER POPS.
UPPER TROUGH SLOWS JUST EAST OF THE AREA THU NIGHT INTO FRI. WRAP
MOISTURE CONTINUES TO BE SHOWN ROTATING SOUTH ACROSS THE EASTERN
PART OF THE CWA THU NIGHT AND FRI. WILL KEEP SMALL CHANCE FOR SHRA
GOING. THINK THE SHRA SHOULD BE DONE BY FRI EVENING BUT WILL KEEP A
SLIGHT CHANCE FOR THE INLAND EAST FOR THE EARLY PART OF FRI EVE TO
GIVE ANY LINGERING CONVECTIVE SHRA A FEW HOURS TO DIE OFF.
WITH CLOUDS LIKELY TO BE OVER THE EAST THU NIGHT WILL ADJUST LOWS UP
A LITTLE MORE.
SOME HIGH CLOUDS MAY BE SPREADING INTO THE AREA LATER FRI NIGHT BUT
STILL SHOULD SEE ENOUGH CLOUD FREE TIME FOR DECENT RADIATIONAL
COOLING TO TAKE PLACE AS THE HIGH MOVES OVERHEAD. LOWS MOST PLACES
LOOK TO BE SEASONALLY COOL WITH READINGS MOSTLY DOWN INTO A 48 TO 55
RANGE.
PROGRESSIVE UPPER FLOW WILL HELP SURFACE HIGH OFF TO THE EAST BY
LATE SAT. MODELS BRING A WEAK UPPER DISTURBANCE INTO THE AREA BY SAT
EVENING. WARM FRONT LIFTING NEAR LERI WILL PROVIDE FOCUS FOR
CONVECTION TO SLIDE SE INTO THE AREA SO WILL INCREASE POP FOR SAT
AFTERNOON AND NIGHT.
&&
.LONG TERM /SUNDAY THROUGH TUESDAY/...
A THREAT OF SHOWERS AND THUNDERSTORMS FOR MUCH OF THIS FORECAST
PERIOD. A THREAT SUNDAY AHEAD OF THE FRONT WHICH WILL MOVE ACROSS
THE AREA SUNDAY NIGHT INTO MONDAY. CONTINUING THE THREAT INTO
TUESDAY WITH AN UPPER TROF ACROSS THE REGION EVEN THOUGH HIGH
PRESSURE IS BUILDING IN AT THE SURFACE. THAT MEANS IT MAY BE MORE
DIURNAL IN NATURE. WENT CLOSE TO WPC FOR THE TEMPERATURE FORECAST.
&&
.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
HIGH PRESSURE OVER THE AREA WITH A DIFFUSE STATIONARY BOUNDARY
WEST TO EAST ACROSS CENTRAL OHIO. THE MORNING ISSUES ARE SOME
PATCHY FOG ACROSS THE FORECAST AREA AND STRATUS FOR NW PA. THEY
WILL BOTH BURN OFF OR RAISE SOMEWHAT RAPIDLY THIS MORNING. SOME
SHOWERS ARE OVER NORTHWEST OHIO AND I AM GOING WITH THEY WILL
DISSIPATE AS THEY MOVE EAST.
OTHERWISE THE ISSUE IS THE TIMING AND STRENGTH OF THE
THUNDERSTORMS FOR THE LATE AFTERNOON AND EVENING. MANY MODELS
INDICATE THE SHOWERS AND THUNDERSTORMS WON`T GET GOING UNTIL AFTER
DARK...WHILE THE HRRR AND THE RUC/RAP STARTS THE SHOWERS AND
THUNDERSTORMS AFTER 21Z. ON THE EDGE ABOUT THAT...TRIED TO LEAN
TOWARD THE MOST SIGNIFICANT SHOWERS AND THUNDERSTORMS OCCURRING DURING
THE OVERNIGHT HOURS AS THE SURFACE LOW MOVES ALONG THE BOUNDARY.
IT SHOULD BE SEVERAL WAVES OF PRECIPITATION. OCCASIONAL
IFR...MAINLY IN THE VISIBILITY AND EVENTUALLY AFTER THE SURFACE
LOW MOVES EAST IFR CEILINGS IN THE NORTHERLY FLOW. WIDESPREAD
STRONG WINDS COULD BE ASSOCIATED WITH THE THUNDERSTORMS IF THEY
FORM A LINE. ALL THIS WILL HAVE TO BE MONITORED.
.OUTLOOK...NON VFR CONDITIONS THURSDAY AND POSSIBLY CONTINUING INTO
THURSDAY NIGHT AND SATURDAY NIGHT AND SUNDAY IN SHOWERS AND THUNDERSTORMS.
&&
.MARINE...
HIGH PRESSURE OVER THE AREA TO START WITH A STATIONARY FRONT WELL
SOUTH OF LAKE ERIE. A LOW WILL MOVE ALONG THE FRONT AND THAT WILL
INCREASE THE WINDS TONIGHT AND THURSDAY...IN THE MEANTIME THE WINDS
WILL BE LIGHT AND VARIABLE. SOME QUESTION HOW CLOSE THE LOW WILL
TRACK TO THE LAKE...WENT MORE WITH THE GFS WHICH TRACKS THE LOW A
LITTLE FARTHER FROM THE LAKE SO THE WINDS MAY BE STRONGER. A SMALL
CRAFT ADVISORY MAY BE NEEDED BY DAYBREAK THURSDAY AND THE THREAT
WILL CONTINUE INTO THURSDAY NIGHT. SPECIAL MARINE WARNINGS MAY BE
NEEDED MAINLY THIS EVENING AND TONIGHT FOR LAKE ERIE.
HIGH PRESSURE WILL BUILD OVER LAKE ERIE FRIDAY NIGHT AND MOVE EAST
SATURDAY NIGHT ALLOWING A SOUTHWEST FLOW TO DEVELOP. THE FLOW WILL
BE STRONG AND THAT MAY CAUSE WAVES TO BE 2 TO 4 FEET ON THE EAST END
OF THE LAKE. OTHERWISE THE NEXT SIGNIFICANT THREAT FOR A SMALL CRAFT
ADVISORY WILL BE EARLY NEXT WEEK WHEN A COLD FRONT MOVES ACROSS THE
AREA.
&&
.HYDROLOGY...
THE FLOOD THREAT WILL INCREASE WEDNESDAY EVENING INTO THURSDAY
MORNING AS A WARM FRONT AND A DEEPENING LOW MOVE INTO NORTHERN OHIO.
BROAD UPPER LVL DIFFLUENCE AND DEEP SOUTHERLY FLOW AHEAD OF THE
SURFACE LOW WILL SET THE STAGE FOR SOME EFFICIENT RAIN. PRECIPITABLE
WATER VALUES WILL RISE TO 1.6-2.0" AND WITH STORM FORWARD SPEEDS
EXPECTED TO SLOW INTO THE OVERNIGHT HOURS...THERE IS A HIGH THREAT
OF TRAINING STORMS WITH HEAVY RAIN. ON AVERAGE...MUCH OF THE AREA
CAN SEE 1.5 TO 3 INCHES OF RAINFALL FROM THIS EVENT.
THE HEAVIEST RAIN WILL FALL AFTER 8 PM WEDNESDAY THROUGH 8 AM
THURSDAY. HIGH RAINFALL RATES ON ALREADY WET GROUND WILL SUPPORT THE
DEVELOPMENT OF FLOODS. ALL RIVERS ARE AT RISK FOR FLOODING WITH THE
POTENTIAL FOR MAJOR FLOODING.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...FLOOD WATCH FROM THIS EVENING THROUGH THURSDAY AFTERNOON FOR
OHZ011>014-020>023-031>033-038-089.
FLOOD WATCH FROM 6 PM EDT THIS EVENING THROUGH THURSDAY
AFTERNOON FOR OHZ003-006>010-017>019-027>030-036-037-047.
PA...FLOOD WATCH FROM THIS EVENING THROUGH THURSDAY AFTERNOON FOR
PAZ001>003.
MARINE...NONE.
&&
$$
SYNOPSIS...ADAMS
NEAR TERM...LOMBARDY
SHORT TERM...ADAMS
LONG TERM...KIELTYKA
AVIATION...KIELTYKA
MARINE...KIELTYKA
HYDROLOGY...JAMISON/ADAMS
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
745 AM EDT WED JUN 12 2013
.SYNOPSIS...
LOW PRESSURE WILL MOVE ALONG A FRONT STALLED OVER THE AREA TONIGHT
AND THURSDAY MORNING. HIGH PRESSURE WILL SLIDE SOUTHEAST THROUGH THE
GREAT LAKES FRIDAY THROUGH SATURDAY AND TO THE CAROLINA COAST
SUNDAY. ANOTHER LOW WILL MOVE EAST ACROSS THE LAKES SUNDAY AND
MONDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
FOR EARLY MORNING UPDATE...LATEST SHORT TERM MODEL RUNS ALL OVER THE
PLACE WITH QPF THRU MID AFTERNOON SO NOT CONFIDENT IN ANY OF THIS
NEW INFORMATION. CURRENT REGIONAL RADAR SHOWS MOST OF THE SHRA OVER
THE EASTERN PART OF THE CWA HAVE MOVED OFF TO THE SE WHILE BAND OF
LIGHT SHRA HAS CONTINUED TO PUSH SE ACROSS LWR MI INTO EXTREME NW
CORNER OF OH. WILL ALLOW FOR THIS BAND TO MAKE SLOW EASTWARD
PROGRESS THRU EARLY AFTERNOON BUT NOT QUITE AS FAST AS HRRR. THUS
CHC POPS SPREAD INTO CLE AND CAK AREA BY NOON.
THE INGREDIENTS ARE STILL LOOKING TO COME TOGETHER TODAY INTO
TONIGHT FOR STRONG TO SEVERE STORMS TO SPREAD ACROSS THE AREA.
WITH A WEAK FRONT STALLED OVER THE CWA THERE SHOULD BE A GOOD TEMP
GRADIENT WITH TODAY HIGHS WHICH SHOULD RANGE FROM THE MID 70S IN THE
FAR NE LAKESHORE TO THE MID TO UPPER 80S IN THE EXTREME SW.
QUESTION TODAY IS HOW MUCH CONVECTION WILL GET GOING AND HOW
QUICKLY. LATEST NAM RUN BARELY PRODUCES A TENTH OF AN INCH OF QPF
NEAR THE FDY AREA WITH LESSER AMOUNTS OVER THE REST OF THE CWA.
FLOOD WATCH FOR TONIGHT INTO THU MORNING SET TO START IN THE WEST AT
22Z THIS EVENING.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY NIGHT/...
THIS LOOKS TO BE ONE OF THE BEST SETUPS FOR A CONVECTIVE COMPLEX TO
WORK ACROSS THE CWA THAT WE`VE SEEN IN A WHILE. NOT SAYING THERE
WILL BE A DERECHO BUT THE POSSIBILITY IS THERE. TRACK OF THE CORE OF
THE CONVECTION HAS BEEN CONSISTENT FOR SEVERAL DAYS SO WILL STAY
WITH POPS 90 PERCENT OR BETTER AT SOME POINT TONIGHT INTO THU
MORNING FOR THE WHOLE CWA.
WITH P/W`S RUNNING CLOSE TO 2 INCHES FOR MOST OF THE AREA SEE NO
REASON NOT TO HAVE A FLOOD WATCH GOING. ENOUGH QPF STILL SHOWN FOR
THU MORNING TO SLOW POP DRAW DOWN SOME.
QUESTION WHETHER THINGS WILL BE ABLE TO RECOVER FROM MORNING PRECIP
AND CLOUDS TO ALLOW AIRMASS TO DESTABILIZE ENOUGH FOR SOME WIDELY
SCT AFTERNOON CONVECTION TO DEVELOP. GFS HAS BEEN CONSISTENTLY
TRYING TO REDEVELOP SOME SHRA OVER THE WEST THU AFTERNOON AS A
RESULT OF FORCING FROM PRESENCE OF UPPER TROUGH. COOLER FLOW OUT OF
THE NORTH BEHIND THE LOW THU AFTERNOON...ALONG WITH GENERAL
SUBSIDENCE AND DRIER AIR WOULD SEEM TO MAKE IT FAIRLY TOUGH TO ALLOW
FOR MUCH CONVECTION TO DEVELOP. GUIDANCE POPS FOR 18Z THRU 00Z THU
EVE VERY LOW AND THIS SEEM TO MAKE SENSE SO WILL LOWER POPS.
UPPER TROUGH SLOWS JUST EAST OF THE AREA THU NIGHT INTO FRI. WRAP
MOISTURE CONTINUES TO BE SHOWN ROTATING SOUTH ACROSS THE EASTERN
PART OF THE CWA THU NIGHT AND FRI. WILL KEEP SMALL CHANCE FOR SHRA
GOING. THINK THE SHRA SHOULD BE DONE BY FRI EVENING BUT WILL KEEP A
SLIGHT CHANCE FOR THE INLAND EAST FOR THE EARLY PART OF FRI EVE TO
GIVE ANY LINGERING CONVECTIVE SHRA A FEW HOURS TO DIE OFF.
WITH CLOUDS LIKELY TO BE OVER THE EAST THU NIGHT WILL ADJUST LOWS UP
A LITTLE MORE.
SOME HIGH CLOUDS MAY BE SPREADING INTO THE AREA LATER FRI NIGHT BUT
STILL SHOULD SEE ENOUGH CLOUD FREE TIME FOR DECENT RADIATIONAL
COOLING TO TAKE PLACE AS THE HIGH MOVES OVERHEAD. LOWS MOST PLACES
LOOK TO BE SEASONALLY COOL WITH READINGS MOSTLY DOWN INTO A 48 TO 55
RANGE.
PROGRESSIVE UPPER FLOW WILL HELP SURFACE HIGH OFF TO THE EAST BY
LATE SAT. MODELS BRING A WEAK UPPER DISTURBANCE INTO THE AREA BY SAT
EVENING. WARM FRONT LIFTING NEAR LERI WILL PROVIDE FOCUS FOR
CONVECTION TO SLIDE SE INTO THE AREA SO WILL INCREASE POP FOR SAT
AFTERNOON AND NIGHT.
&&
.LONG TERM /SUNDAY THROUGH TUESDAY/...
A THREAT OF SHOWERS AND THUNDERSTORMS FOR MUCH OF THIS FORECAST
PERIOD. A THREAT SUNDAY AHEAD OF THE FRONT WHICH WILL MOVE ACROSS
THE AREA SUNDAY NIGHT INTO MONDAY. CONTINUING THE THREAT INTO
TUESDAY WITH AN UPPER TROF ACROSS THE REGION EVEN THOUGH HIGH
PRESSURE IS BUILDING IN AT THE SURFACE. THAT MEANS IT MAY BE MORE
DIURNAL IN NATURE. WENT CLOSE TO WPC FOR THE TEMPERATURE FORECAST.
&&
.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
HIGH PRESSURE OVER THE AREA WITH A DIFFUSE STATIONARY BOUNDARY
WEST TO EAST ACROSS CENTRAL OHIO. THE MORNING ISSUES ARE SOME
PATCHY FOG ACROSS THE FORECAST AREA AND STRATUS FOR NW PA. THEY
WILL BOTH BURN OFF OR RAISE SOMEWHAT RAPIDLY THIS MORNING. SOME
SHOWERS ARE OVER NORTHWEST OHIO AND I AM GOING WITH THEY WILL
DISSIPATE AS THEY MOVE EAST.
OTHERWISE THE ISSUE IS THE TIMING AND STRENGTH OF THE
THUNDERSTORMS FOR THE LATE AFTERNOON AND EVENING. MANY MODELS
INDICATE THE SHOWERS AND THUNDERSTORMS WON`T GET GOING UNTIL AFTER
DARK...WHILE THE HRRR AND THE RUC/RAP STARTS THE SHOWERS AND
THUNDERSTORMS AFTER 21Z. ON THE EDGE ABOUT THAT...TRIED TO LEAN
TOWARD THE MOST SIGNIFICANT SHOWERS AND THUNDERSTORMS OCCURRING DURING
THE OVERNIGHT HOURS AS THE SURFACE LOW MOVES ALONG THE BOUNDARY.
IT SHOULD BE SEVERAL WAVES OF PRECIPITATION. OCCASIONAL
IFR...MAINLY IN THE VISIBILITY AND EVENTUALLY AFTER THE SURFACE
LOW MOVES EAST IFR CEILINGS IN THE NORTHERLY FLOW. WIDESPREAD
STRONG WINDS COULD BE ASSOCIATED WITH THE THUNDERSTORMS IF THEY
FORM A LINE. ALL THIS WILL HAVE TO BE MONITORED.
.OUTLOOK...NON VFR CONDITIONS THURSDAY AND POSSIBLY CONTINUING INTO
THURSDAY NIGHT AND SATURDAY NIGHT AND SUNDAY IN SHOWERS AND THUNDERSTORMS.
&&
.MARINE...
HIGH PRESSURE OVER THE AREA TO START WITH A STATIONARY FRONT WELL
SOUTH OF LAKE ERIE. A LOW WILL MOVE ALONG THE FRONT AND THAT WILL
INCREASE THE WINDS TONIGHT AND THURSDAY...IN THE MEANTIME THE WINDS
WILL BE LIGHT AND VARIABLE. SOME QUESTION HOW CLOSE THE LOW WILL
TRACK TO THE LAKE...WENT MORE WITH THE GFS WHICH TRACKS THE LOW A
LITTLE FARTHER FROM THE LAKE SO THE WINDS MAY BE STRONGER. A SMALL
CRAFT ADVISORY MAY BE NEEDED BY DAYBREAK THURSDAY AND THE THREAT
WILL CONTINUE INTO THURSDAY NIGHT. SPECIAL MARINE WARNINGS MAY BE
NEEDED MAINLY THIS EVENING AND TONIGHT FOR LAKE ERIE.
HIGH PRESSURE WILL BUILD OVER LAKE ERIE FRIDAY NIGHT AND MOVE EAST
SATURDAY NIGHT ALLOWING A SOUTHWEST FLOW TO DEVELOP. THE FLOW WILL
BE STRONG AND THAT MAY CAUSE WAVES TO BE 2 TO 4 FEET ON THE EAST END
OF THE LAKE. OTHERWISE THE NEXT SIGNIFICANT THREAT FOR A SMALL CRAFT
ADVISORY WILL BE EARLY NEXT WEEK WHEN A COLD FRONT MOVES ACROSS THE
AREA.
&&
.HYDROLOGY...
THE FLOOD THREAT WILL INCREASE WEDNESDAY EVENING INTO THURSDAY
MORNING AS A WARM FRONT AND A DEEPENING LOW MOVE INTO NORTHERN OHIO.
BROAD UPPER LVL DIFFLUENCE AND DEEP SOUTHERLY FLOW AHEAD OF THE
SURFACE LOW WILL SET THE STAGE FOR SOME EFFICIENT RAIN. PRECIPITABLE
WATER VALUES WILL RISE TO 1.6-2.0" AND WITH STORM FORWARD SPEEDS
EXPECTED TO SLOW INTO THE OVERNIGHT HOURS...THERE IS A HIGH THREAT
OF TRAINING STORMS WITH HEAVY RAIN. ON AVERAGE...MUCH OF THE AREA
CAN SEE 1.5 TO 3 INCHES OF RAINFALL FROM THIS EVENT.
THE HEAVIEST RAIN WILL FALL AFTER 8 PM WEDNESDAY THROUGH 8 AM
THURSDAY. HIGH RAINFALL RATES ON ALREADY WET GROUND WILL SUPPORT THE
DEVELOPMENT OF FLOODS. ALL RIVERS ARE AT RISK FOR FLOODING WITH THE
POTENTIAL FOR MAJOR FLOODING.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...FLOOD WATCH FROM THIS EVENING THROUGH THURSDAY AFTERNOON FOR
OHZ011>014-020>023-031>033-038-089.
FLOOD WATCH FROM 6 PM EDT THIS EVENING THROUGH THURSDAY
AFTERNOON FOR OHZ003-006>010-017>019-027>030-036-037-047.
PA...FLOOD WATCH FROM THIS EVENING THROUGH THURSDAY AFTERNOON FOR
PAZ001>003.
MARINE...NONE.
&&
$$
SYNOPSIS...ADAMS
NEAR TERM...ADAMS
SHORT TERM...ADAMS
LONG TERM...KIELTYKA
AVIATION...KIELTYKA
MARINE...KIELTYKA
HYDROLOGY...JAMISON/ADAMS
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
759 AM EDT WED JUN 12 2013
.SYNOPSIS...
A QUASI-STATIONARY FRONT WILL REMAIN DRAPED FROM THE NORTHWEST
CORNER OF THE STATE...TO SOUTH-CENTRAL PENNSYLVANIA TODAY. THIS
FRONTAL BOUNDARY WILL PIVOT SLIGHTLY TO A MORE EAST-WEST DIRECTION
TONIGHT. A POTENT STORM WILL RIDE ALONG THIS BOUNDARY...PASSING OVER
SOUTHERN OR CENTRAL PENNSYLVANIA ON THURSDAY. A COLD FRONT WILL DIVE
SOUTHEAST ACROSS THE REGION ON FRIDAY...FOLLOWED BY A LARGE HIGH
PRESSURE SYSTEM FOR SATURDAY.
&&
.NEAR TERM /UNTIL NOON TODAY/...
A NEARLY STATIONARY...AND VERY SHARP 925-850 MB THETA-E BOUNDARY WAS
LOCATED FROM KERI...SE TO KFKL...KAOO AND KHGR EARLY THIS MORNING.
A PULSE OF HIGHER PWAT AIR AND WESTERLY FLOW AROUND THE 850 MB LEVEL
IMPINGING ON THIS BOUNDARY WILL HELP TO FORM ONE OR MORE AREAS OF
SHOWERS THAT WILL SLIDE SEWRD /NEAR AND JUST TO THE EAST OF THE
BOUNDARY/ THIS MORNING. ONE OR TWO...COMPACT AND LOW-TOPPED TSRA
CAN/T BE RULED OUT ACROSS THE LAURELS THIS MORNING ON THE SW SIDE OF
THE BOUNDARY.
RAINFALL AMOUNTS WILL BE GENERALLY LIGHT AND LESS THAN ONE TENTH OF
AN INCH ACROSS THE CENTRAL AND WESTERN ZONES. HOWEVER...SHORT
RANGE/HIGH RES NAM AND HRRR GUIDANCE IMPLIES THAT A FEW LOCATIONS
COULD RECEIVE SLIGHTLY HIGHER AMOUNTS THROUGH 15Z.
THE HIGHER PWAT AIR AND LLVL BOUNDARY IS BRIEFLY SHUNTED A BIT TO
THE SOUTHWEST THIS AFTERNOON...THANKS TO VERTICAL MIXING OF MUCH
DRIER AIR ALOFT AHEAD OF WEAK RIDGING THAT WILL BE SLIDING EAST OVER
THE REGION.
LOW TEMPS AROUND DAYBREAK TODAY WILL RANGE FROM THE MID 50S OVER THE
NORTH TO AROUND 60 IN THE SOUTH.
&&
.SHORT TERM /NOON TODAY THROUGH 6 PM THURSDAY/...
QUASI-STATIONARY FRONT STAYS HUNG UP OVER SWRN PA THROUGH TODAY.
DESPITE LACK OF SIG LG SCALE FORCING ON WED...DIURNAL HEATING
COMBINED LIFT ALONG STATIONARY FRONT SHOULD SUPPORT SCT AFTN/EVENING
SHOWERS AND THUNDERSTORMS OVER MY SW COUNTIES.
EXPECT SKIES TO STAY MOSTLY CLOUDY FOR MUCH OF TODAY WITH VARYING
AMOUNTS OF HIGH-BASED STRATO CU AND ALTO CU STREAMING SEWRD ACROSS
THE STATE.
SPC HAS TRANSITIONED FROM THEIR DAY 2 TO DAY 1 SLIGHT /AND MDT/ RISK
AREAS OVER THE SW HALF OF PENN...OUT THROUGH THE OHIO VALLEY -
VIRTUALLY UNCHANGED.
THINKING IS THAT THE PRIMARY RISK FOR OUR REGION WILL BE ASSOCIATED
WILL LATER DEVELOPMENTS OVER THE MIDWEST THAT COULD MOVE IN TONIGHT
AND EARLY THURSDAY...SO FOR RIGHT NOW THIS AFTERNOON AND EVENING
DOESN/T LOOK TERRIBLY THREATENING OVERALL...AS THE BEST INSTABILITY
SOUTH AND WEST OF OUR AREA OF CONCERN THROUGH MOST OF THIS TIME
FRAME.
ALTHOUGH CLOUDS MAY PREDOMINATE TODAY...BREAKS OF SUN AND LOW
CHANCES FOR PRECIP DURING THE LATE MORNING AND AFTERNOON HOURS
SHOULD ALLOW TEMPS TO RECOVER TO NEAR NORMAL OVR THE NORTH AND
LIKELY A BIT ABV NORMAL IN THE SOUTH...WHERE ENS MEAN 8H TEMPS GET
CLOSE TO 15C. MUCH HIGHER PWAT AIR WILL BEGIN IT/S BIG SURGE NE
ACROSS THE FCST AREA VERY LATE TODAY AND TONIGHT.
ABNORMALLY STRONG DYNAMICS WILL SUPPORT A DEEP LOW MOVING ACROSS
SCENT PA ON THU.
POTENT UPPER SHORT WAVE ACCOMPANIED BY A STRONG WSWRLY LLJ /AND THE
SUB-1000MB SFC LOW/ WILL IMPACT ALL OF THE REGION THURSDAY WITH A
WIDE RANGE OF TEMPERATURES AND WEATHER.
LATEST...00Z/03Z OPERATIONAL MODELS AND THEIR RESPECTIVE ENSEMBLES
REMAIN IN VERY GOOD AGREEMENT TRACKING AN ANOMALOUSLY STRONG 990-995
MB SFC LOW ACROSS CENTRAL OR SOUTHERN PENN DURING THE DAY THURSDAY.
DEEP UVVEL BENEATH THE THERMALLY DIRECT BRANCH OF AN UPPER JET
LOCATED ACROSS NEW YORK AND SRN NEW ENGLAND WILL AID IN STRONG
ASCENT OF THE HIGH PWAT AIR /1.5-2 INCHES/ OVER THE QUASI STNRY OR
SFC WARM FRONT /EXPECTED TO BE SITUATED FROM WCENT PENN TO THE SCENT
MTNS AND LOWER SUSQ VALLEY/. THESE FACTORS WILL COMBINE TO PRODUCE A
WIDESPREAD...SOAKING RAINFALL OF 1-2 INCHES ACROSS THE NORTHERN HALF
OF THE STATE. 24 SREF PROB FOR 2 INCH OR GREATER RAINFALL IS 40-50
PERCENT ACROSS THE NORTHERN 1/2 OF PENN...WHILE ITS 24 HR
PROBABILITY FOR OVER 1 INCH OF QPF IS 60-80 PERCENT STATE-WIDE.
ACROSS THE SOUTH...IN THE MUCH WARMER AND MORE HUMID AIR /ESP NEAR
AND TO THE SOUTH OF THE PENN TURNPIKE/...SIGNIFICANT BREAKS IN THE
CLOUD COVER MAY DEVELOP HELPING TO RAMP UP MUCAPES TO BETWEEN
2000-3000 J/KG IN THE AFTERNOON. THIS CONVECTIVE ENERGY WILL BE NEAR
THE NORTHERN EDGE OF THE MOST ANOMALOUS /PLUS 3 SIGMA/ WSW 850 MB
FLOW.
A RATHER BROAD AREA OF UNUSUALLY HIGH...0-1KM EHI FOR THIS AREA /OF
AROUND 2-3M2/S2/ IS FCST TO DEVELOP NEAR AND JUST SOUTH OF THE
SLOW-MOVING WARM FRONTAL BOUNDARY TO POSE A THREAT FOR BOWING LINE
SEGMENTS WITH SCATTERED SUPERCELLS/ISOLATED TORNADOES POSSIBLE FROM
THE LATE MORNING THROUGH THE AFTERNOON HOURS. SPC HAS COVERED
ROUGHLY THE SERN HALF OF PENN WITH THEIR DAY 2 SLIGHT RISK
AREA...WHILE THE FAR SERN ZONES ARE AT THE NW EDGE OF A MDT RISK
/WHICH EXTENDS SOUTH THROUGH THE I-95...MID ATLANTIC CORRIDOR/.
A RIBBON OF VERY IMPRESSIVE /AND NOT OFTEN SEEN IN THIS AREA/ 0-1KM
EHIS OF 4M2/S2 OR GREATER DEVELOP ACROSS THE LOWER SUSQ WHERE THE
MID-LATE AFTERNOON TIMING OF THE BEST INSTABILITY AND LLVL SHEAR
WILL OCCUR INVOF OF THE THE SHARP STNRY FRONT /OR SLOWLY MOVING WARM
FRONTAL BOUNDARY/. SIGNIF PERCENTAGE OF THE STORMS IN THE LOWER SUSQ
COULD CONTAIN MDT TO STRONG MESOS FOR UP TO SVRL HOURS THURSDAY
AFTERNOON AND EVENING INVOF KTHV...KMDT AND KLNS WITH AN ENHANCED
THREAT FOR A FEW TORNADOES IN THAT AREA. LOW LCL HEIGHTS AND THE
VERY STRONG SOUTH-SWRLY 0-1KM SHEAR NEAR AND JUST TO THE NORTH OF
THE BOUNDARY WILL CREATE THE GREATEST THREAT FOR THE SUPERCELLS WITH
POSSIBLE LARGE HAIL IN THE 17Z-22Z PERIOD ACROSS THE LOWER SUSQ
VALLEY.
AS HIGHLIGHTED LAST NIGHT...THE NORTH-SOUTH SFC TEMP GRADIENT
THURSDAY AFTERNOON SHOULD TURN OUT TO BE QUITE SHARP...ESPECIALLY IF
SIGNIFICANT BREAKS FORM ACROSS THE SOUTH.
EARLIER WENT ALL IN BY RAISING POPS TO 100 PERCENT FOR THE ENTIRE
AREA THURSDAY...AND THIS LOOKS TO BE A WISE MOVE BASED ON THE SHORT
RANGE OPERATIONAL AND ENSEMBLE MODEL CONSENSUS OF WIDESPREAD HEAVY
RAIN AND CONVECTION.
WILL MAINTAIN TEMPS BELOW GUIDANCE...GIVEN CLDS AND SOAKING RAIN
BENEATH THE WELL DEFINED...THERMALLY DIRECT BRANCH OF A STRONG UPPER
LEVEL JET. THE SECOND CONCERN IS HEAVY RAIN...AND POTENTIAL FOR
LOCALIZED FLASH FLOODING/FLOODING OF STREAMS AND CREEKS.
24-30 HOUR...STORM TOTAL QPF RANGES FROM 2-2.5 INCHES ACROSS MUCH OF
NRN PENN...TO SLIGHTLY UNDER ONE INCH IN THE FAR SE.
MARFC IS IN THE 2 TO 3 INCH RANGE FOR STORM TOTAL QPF. MOST PLACES
SHOULD BE ABLE TO HANDLE THIS AMT OF RAIN OVER A 12-24 HOUR PERIOD.
HOWEVER...IF MUCH OF THIS COMES DOWN IN JUST A 3-6 HOUR
PERIOD...SIGNIFICANT PROBLEMS COULD DEVELOP QUICKLY IN TYPICALLY
FLOOD PRONE AREAS.
COORDINATED WITH SURROUNDING WFOS TO HOLD OFF ON A FLASH FLOOD WATCH
AT THIS POINT...ESP SINCE THE BULK OF THE RAIN IS STILL CONFINED TO
THE 3RD PERIOD OF THE FCST...AND FFG FOR OUR CWA IS SOME OF THE
HIGHEST OBSERVED IN THE ENTIRE MID-ATLANTIC REGION /2.25 - 3 INCHES
PER 12 HOURS OVER OUR ENTIRE CWA/. AREAS TO THE WEST AND EAST OF OUR
FCST AREA NEED SIGNIFICANTLY LOWER AMOUNTS OF RAIN TO CAUSE FLOODING
PROBLEMS...ESPECIALLY OVER TO OUR EAST.
&&
.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
DID LOWER TEMPS ON FRIDAY BY 2 TO 5 DEGREES...COMBINATION OF
SECONDARY COLD FRONT DROPPING SOUTHWARD FROM SOUTHERN
ONTARIO...AND DEEP LOW MOVING OFF THE COAST WILL SUPPORT MORE COLD
ADVECTION AND ALSO SOME SHOWERS FRIDAY MORNING.
IMPROVING CONDITIONS FOR SAT.
WENT WITH A LOW CHC FOR SHOWERS AND STORMS ON SUNDAY...GIVEN
WARM ADVECTION.
CHC OF MORE SHOWERS AND STORMS ON MONDAY AND TUE...AS THE WARM
FRONT MOVES NE ON MONDAY...FOLLOWED BY A COLD FRONT ON TUE.
&&
.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
A QUASI-STATIONARY FRONTAL BOUNDARY WILL SAG SLOWLY SOUTHWARD
ACROSS WESTERN PENNSYLVANIA TODAY. A POTENT STORM WILL RIDE ALONG
THIS BOUNDARY LATE WED NIGHT THROUGH THU NIGHT.
KBFD WILL REMAIN IFR/MVFR FOR A COUPLE MORE HOURS. AREA OF MVFR
CIGS HAS EXPANDED SOUTH AND EAST INTO THE LAURELS AND SOUTH
CENTRAL MTNS AS SHORTWAVE SLIPS OVERHEAD WITH ENOUGH LIFT TO
DEVELOP STRATOCU UNDER INVERSION. SCT SHOWERS IN THAT REGION WILL
CONTINUE TO DECREASE THROUGH MID MORNING...WITH ALL TAF SITES
IMPROVING TO VFR 14-15Z AS LOWER LAYER MIXES AND HIGH PRESSURE
SLIDES ACROSS NY STATE. DESPITE LACK OF SIG LARGE SCALE
FORCING...DIURNAL HEATING COMBINED WITH LIFT ALONG STATIONARY
FRONT SHOULD SUPPORT SCT AFTN/EVENING TSTMS NEAR KJST- KAOO.
THEN FOCUS TURNS TO POTENT LOW PRESSURE SYSTEM APPROACHING FROM
THE MIDWEST...WITH IMPACTS BEGINNING WED NIGHT. LARGE AREA OF
PRECIP OVERSPREADS REGION FROM THE WEST AS NIGHT PROGRESSES.
MODELS INDICATING THAT CIGS REMAIN PRIMARILY VFR EXCEPT ACROSS THE
WEST...WHERE RESTRICTIONS WILL DEVELOP. RAIN CONTINUES THROUGH
THURSDAY NIGHT...WITH POTENTIAL FOR LARGE IMPACTS FROM STRONG
THUNDERSTORMS AND WIND SHEAR THU AFT INTO THU EVE.
LLWS WILL DEVELOP IN THE SW LATE TONIGHT...WITH STRONGER LOW LEVEL
WINDS IN STORE FOR ALL ON THURSDAY.
OUTLOOK...
WED NIGHT-THU MORN...RAIN AND SCT TSTMS BECOMING MORE WIDESPREAD.
REDUCTIONS DEVELOPING...MAINLY WEST.
THU AFT-THU NIGHT...LARGE IMPACTS FROM STRONG TSTMS AND WIND SHEAR
LIKELY. OTHERWISE SHOWERS CONTINUE. REDUCTIONS ALL AREAS THU AFT-
EVE...THEN WIDESPREAD REDUCTIONS NW HALF THU NIGHT.
FRI...CHANCE OF SHOWERS...MAINLY EARLY. PRIMARILY VFR CONDITIONS.
SAT...NO SIG WX.
SUN...NO SIG WX. ISO TSTMS LATE.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...LAMBERT
NEAR TERM...LAMBERT
SHORT TERM...FITZGERALD/LAMBERT
LONG TERM...MARTIN
AVIATION...RXR
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
954 AM EDT WED JUN 12 2013
.SYNOPSIS...
WARM HIGH PRESSURE WILL BUILD ACROSS THE REGION TODAY...AHEAD OF AN
APPROACHING COLD FRONT...WHICH WILL CROSS THE AREA ON THURSDAY. DRY
HIGH PRESSURE WILL BUILD IN FROM THE NORTH FRIDAY THROUGH THE
WEEKEND. ANOTHER COLD FRONT WILL APPROACH THE REGION EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 0955 AM...CURRENT RADAR TRENDS AND LATEST HRRR SUGGEST THAT WE
SHOULD BACK OFF ON THE IDEA THAT A CONVECTIVE COMPLEX WILL MOVE SE
ACROSS THE AREA OUT OF WV AND ACROSS THE FORECAST AREA THIS
AFTERNOON. PREVIOUS CONVECTION OVER WV HAS WANED AS IT MOVED SE INTO
A MORE STABLE AIRMASS. IN FACT...FORECAST SOUNDINGS AS MENTIONED
PREVIOUSLY LOOK CAPPED WITH CONSIDERABLE LOW LEVEL CIN. WILL HAVE
THE HIGHEST POPS OVER THE FAR EASTERN NC PIEDMONT WHERE SOME STORMS
CAN`T BE RULED OUT AND OVER THE FAR WEST...IN NE GA AND WESTERN
UPSTATE WHERE THE 06Z NAM HAD SOME QPF RESPONSE. ALSO ADJUSTED
TEMPS/DEWPOINTS/WINDS BASED ON LATEST TRENDS AND LAMP DATA. SOME
SOME LIGHT WIDELY SCATTERED LIGHT SHOWERS SHOWING UP ON RADAR ACROSS
THE WESTERN UPSTATE PROBABLY IN ASSOCIATION WITH A PASSAGE OF A MID
LEVEL VORT CENTER PER NAM/GFS. HAVE SOME WIDELY SCATTERED POPS EARLY
TO HANDLE THOSE.
PREVIOUS DISCUSSION:
AS OF 730 AM...CURRENT FORECAST TRENDS LOOK GOOD. MAIN FORECAST
PROBLEM IS WHETHER ANY SIGNIFICANT DEEP CONVECTION WILL OCCUR.
FORECAST SOUNDINGS LOOK CAPPED ALL DAY WITH CONSIDERABLE LOW LEVEL
CIN...BUT SOME CONVECTION ALLOWING MODELS LIKE THE EMC WRF AND
HI-RES WRF TAKE THE CURRENT CONVECTION OVER WV SE AND AND DEVELOP A
MCS WHICH PLOWS THROUGH THE AREA THIS AFTERNOON. HOWEVER...LATEST
HRRR AND LOCAL WRF ARE MUTED AND WEAKEN THE CONVECTION AS IT MOVES
SE INTO THE CURRENTLY MUCH LESS STABLE ENVIRONMENT AS DEPICTED BY
SPC MESOANAL PAGE. LOW END CHC POPS ARE CURRENTLY IN THE GRIDS AND
THAT LOOKS FINE FOR NOW. WILL EVALUATE TRENDS AND TRY TO FINE TUNE
FORECAST LATER THIS MORNING. A FEW LIGHT SHRA HAVE SHOWN UP ON RADAR
ACROSS THE NORTHERN UPSTATE FALLIGN OUT OF A MID LEVEL DECK. HAVFE
ADDED SOME WIDELY SCT POPS TO HANDLE THAT. EXPECT THOSE SHRA TO
DISSIPATE THIS MORNING.
PREVIOUS DISCUSSION...
FOR TODAY...A COUPLE OF INTERESTING THINGS TO DISCUSS. OVERALL...
THE WESTERN CAROLINAS WILL BE UNDER A NW FLOW ALOFT WITH THE
POTENTIAL FOR MESOSCALE VORT CENTERS TO MOVE DOWN ACROSS THE REGION.
WEAK HIGH PRESSURE AT THE SURFACE WILL NOSE IN FROM THE SOUTHWEST.
EXPECTED THE MAIN STORY TO BE THE HEAT...WITH GUIDANCE FOR THE LAST
SEVERAL DAYS SHOWING UPPER 90S E OF THE MTNS...OWING TO DOWNSLOPE
FLOW AND A STRONG CAPPING INVERSION. HOWEVER...QUICK DOWNWARD TREND
HAS DEVELOPED IN THE GUIDANCE...WHICH SEEMS REASONABLE GIVEN THE
AMOUNT OF MID AND HIGH LEVEL CONVECTIVE DEBRIS EXPECTED INTO THE MID
AFTERNOON. OUR FCST HIGHS ARE MUCH MORE IN LINE WITH A GUIDANCE
BLEND SO THERE IS LITTLE CHANGE FROM THE PREVIOUS FCST IN THAT
REGARD. PREVIOUS THOUGHTS WERE ALSO THAT DEEP CONVECTION WOULD BE
HIGHLY DISCOURAGED DUE TO A FORMIDABLE CAPPING INVERSION. THE NEW
GUIDANCE SUGGESTS THAT IT MIGHT NOT BE SO UNBREAKABLE LATE IN THE
AFTERNOON. SOME OF THE CONVECTION ALLOWING MODELS DEVELOP A
THUNDERSTORM COMPLEX OVER THE CENTRAL APPALACHIANS THIS AFTERNOON
THAT PLOWS SOUTHWARD ACROSS THE PIEDMONT OF THE CAROLINAS THROUGH
EARLY EVENING. IF THAT WERE TO HAPPEN...THERE WOULD BE ENOUGH
DOWNDRAFT CAPE FOR SEVERAL SWATHS OF WIND DAMAGE. THE GFS IS STILL
BASICALLY DRY AND CAPPED...BUT THE NAM SUGGESTS NUMEROUS STORMS. IT
SEEMS THE MOST LIKELY SCENARIO IS FOR STORM COVERAGE TO REMAIN
LIMITED BECAUSE OF THE CAP THAT MIGHT NOT BE OVERCOME UNTIL AFTER
21Z...BUT WARY OF ANY BLOWUP OF CONVECTION OVER SRN WV/SW VA...THAT
WOULD REQUIRE A QUICK OVERHAUL OF PRECIP CHANCES. THE CONVECTION IF
IT DEVELOPS WILL MOVE OFF TO THE S IN THE MID EVENING. THEN
ATTENTION TURNS TO THE NEXT POSSIBLE UPSTREAM MCS APPROACHING FROM
THE NW TOWARD DAYBREAK THURSDAY. AT THIS POINT...IT APPEARS THAT IT
WOULD NOT REACH THE MTNS BEFORE SUNRISE...SO THE POP WILL BE KEPT
LOW AT THE VERY END OF THE PERIOD.
&&
.SHORT TERM /THURSDAY THROUGH SATURDAY/...
AS OF 245 AM WEDNESDAY...MODELS HAVE BEEN TRENDING A LITTLE BIT
SLOWER AND DEEPER WITH A SFC LOW...AS IT RACES ACRS PA INTO THE NRN
MID ATLANTIC COASTAL WATERS ON THURSDAY. THE BEST UPPER FORCING
LOOKS TO BE NEAR THIS SFC LOW...WHILE THE BEST INSTBY WILL BE OVER
THE TN VALLEY AND NRN GULF STATES. THE RESULT IS FOR A SORT OF GSP
SPLIT IN THE QPF RESPONSE...AND HENCE PERHAPS LESS OF A SEVERE
THREAT THAN EARLIER ANTICIPATED. THE ENVIRONMENT STILL LOOKS
FAVORABLE FOR SEVERE STORMS...MAINLY DURING THE AFTN HOURS AS A
FRONTAL BAND DEVELOPS/INTENSIFIES JUST OFF THE BLUE RIDGE AND
CROSSES THE PIEDMONT. STILL LOOKING AT 2000+ J/KG OF CAPE EAST OF
THE MTNS WITH BULK SHEAR OF 25-35 KTS. THE NEW DAY 2 CONVECTIVE
OUTLOOK KEEPS THE AREA IN A SLGT RISK...WITH A MODERATE RISK FOR
MORE WIDESPREAD WIND DAMAGE TO OUR NE CLOSER TO THE SFC LOW. WILL
ONLY MAKE MINOR TWEAKS TO THE HWO WORDING THIS MORNING. TEMPS WILL
PROBABLY BE ABLE TO WARM UP INTO THE LWR-MID 90S AHEAD OF THE
FRONT/CONVECTION EAST OF THE MTNS.
THE LINE OF CONVECTION AND COLD FRONT SHUD PUSH THRU THE SE CORNER
OF THE CWFA BY LATE EVENING...WITH DRY HIGH PRES BUILDING IN FOR
FRIDAY AND SATURDAY. POPS TAPER OFF THURSDAY EVENING...AND REMAIN
BELOW 15% THRU SATURDAY. TEMPS RETURN TO NEAR OR SLIGHTLY BELOW
NORMAL READINGS WITH A NOTICEABLE DROP IN HUMIDITY TOO.
&&
.LONG TERM /SATURDAY NIGHT THROUGH TUESDAY/...
AS OF 300 AM WEDNESDAY...MODELS IN GOOD AGREEMENT ON THE SRN CONUS
UPR RIDGE BREAKING DOWN SOMEWHAT BY THE END OF THE WEEKEND...WITH A
RETURN OF WLY UPR FLOW AND THE SHORTWAVE TRACK OVER THE CWFA FOR
EARLY NEXT WEEK. THE RIDGE WILL RE-ESTABLISH OVER THE SRN PLAINS BY
MIDWEEK...KEEPING THE ERN STATES IN PERSISTENT UPR TROFINESS. THIS
WILL LIKELY RESULT IN UNSETTLED WX RETURNING TO THE AREA FOR NEXT
WEEK...WITH SLIGHTLY ABOVE NORMAL TEMPS.
&&
.AVIATION /14Z WEDNESDAY THROUGH SUNDAY/...
AT KCLT...VFR THROUGH THE FORECAST PERIOD. THE FCST SOUNDINGS FROM
MOST MODELS ARE CAPPED...SO ONLY A FEW HIGH BASED STRATOCU ARE
EXPECTED THROUGH MOST OF THE AFTERNOON...UNDERNEATH SOME MID AND
HIGH LEVEL CONVECTIVE DEBRIS MOVING DOWN FROM THE NW. WIND SHOULD
COME AROUND TO WSW BECAUSE OF A LEE TROF BY LATE MORNING. AND NOW HERE IS
THE CAVEAT...SOME OF THE CONVECTION ALLOWING MODELS SUGGEST A
COMPLEX OF THUNDERSTORMS WILL DEVELOP OVER SRN WV AND THEN PLOW
SOUTHWARD ACROSS THE PIEDMONT OF NC IN THE AFTERNOON...PERHAPS WITH
DECENT POTENTIAL FOR DAMAGING WIND GUSTS AND LARGE HAIL. IN THAT
CASE...THE CAP WOULD WORK TO THE ADVANTAGE OF THE STORMS BY HOLDING
THE LID ON THE DEEP CONVECTION AND STORING UP ALL THE ENERGY UNTIL
THE SQUALL LINE ARRIVES TO RELEASE IT. THIS IS ALL CONJECTURE.
RECENT RADAR IMAGERY SUGGESTS THIS MIGHT COME TO FRUITION. FOR NOW
THIS WILL BE INDICATED WITH A PROB30 FOR TSRA IN THE 21Z TO 23Z TIME
FRAME. WILL TRY TO GET A BETTER HANDLE ON THE CONVECTIVE THREAT THIS
MORNING. THE EVENING SHOULD BECOME UNEVENTFUL WITH LIGHT WIND AFTER
SUNSET.
ELSEWHERE...EXPECT MAINLY INCREASING HIGH LEVEL CLOUDS FROM MCS
DEBRIS THROUGH MORNING. THERE COULD BE SOME MVFR VISIBILITY IN THE
VICINITY OF KAVL AROUND SUNRISE. FOR THE AFTERNOON...SCENARIO IS
SIMILAR TO KCLT E OF THE BLUE RIDGE...WITH ISOLATED THUNDERSTORMS
POSSIBLE...BUT WILL NOT MENTION AT THIS TIME.
OUTLOOK...A COLD FRONT WILL BRING A GOOD CHANCE OF SHOWERS AND
THUNDERSTORMS TO THE REGION ON THURSDAY. HIGH PRESSURE WILL BUILD IN
BEHIND THE FRONT AND PRODUCE GENERALLY QUIET WEATHER AND VFR
CONDITIONS THROUGH THE WEEKEND.
CONFIDENCE TABLE...
14-20Z 20-02Z 02-08Z 08-14Z
KCLT HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KGSP HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAVL HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KHKY HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KGMU HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAND HIGH 100% HIGH 100% 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...ARK
NEAR TERM...LG
SHORT TERM...ARK
LONG TERM...ARK
AVIATION...PM
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
806 AM EDT WED JUN 12 2013
.SYNOPSIS...
WARM HIGH PRESSURE WILL BUILD ACROSS THE REGION TODAY...AHEAD OF AN
APPROACHING COLD FRONT...WHICH WILL CROSS THE AREA ON THURSDAY. DRY
HIGH PRESSURE WILL BUILD IN FROM THE NORTH FRIDAY THROUGH THE
WEEKEND. ANOTHER COLD FRONT WILL APPROACH THE REGION EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 8 AM...CURRENT FORECAST TRENDS LOOK PRETTY GOOD. MAIN
FORECAST PROBLEM IS WHETHER ANY SIGNIFICANT DEEP CONVECTION WILL
OCCUR. FORECAST SOUNDINGS LOOK CAPPED ALL DAY WITH CONSIDERABLE
LOW LEVEL CIN...BUT SOME CONVECTION ALLOWING MODELS LIKE THE EMC
WRF AND HI- RES WRF TAKE THE CURRENT CONVECTION OVER WV SE AND AND
DEVELOP A MCS WHICH PLOWS THROUGH THE AREA THIS AFTERNOON.
HOWEVER...LATEST HRRR AND LOCAL WRF ARE MUTED AND WEAKEN THE
CONVECTION AS IT MOVES SE INTO THE CURRENTLY MUCH LESS STABLE
ENVIRONMENT AS DEPICTED BY SPC MESOANAL PAGE. LOW END CHC POPS ARE
CURRENTLY IN THE GRIDS AND THAT LOOKS FINE FOR NOW. WILL EVALUATE
TRENDS AND TRY TO FINE TUNE FORECAST LATER THIS MORNING. A FEW
LIGHT SHRA HAVE SHOWN UP ON RADAR ACROSS THE NORTHERN UPSTATE
FALLIGN OUT OF A MID LEVEL DECK. HAVFE ADDED SOME WIDELY SCT POPS
TO HANDLE THAT. EXPECT THOSE SHRA TO DISSIPATE THIS MORNING.
PREVIOUS DISCUSSION...
FOR TODAY...A COUPLE OF INTERESTING THINGS TO DISCUSS. OVERALL...
THE WESTERN CAROLINAS WILL BE UNDER A NW FLOW ALOFT WITH THE
POTENTIAL FOR MESOSCALE VORT CENTERS TO MOVE DOWN ACROSS THE REGION.
WEAK HIGH PRESSURE AT THE SURFACE WILL NOSE IN FROM THE SOUTHWEST.
EXPECTED THE MAIN STORY TO BE THE HEAT...WITH GUIDANCE FOR THE LAST
SEVERAL DAYS SHOWING UPPER 90S E OF THE MTNS...OWING TO DOWNSLOPE
FLOW AND A STRONG CAPPING INVERSION. HOWEVER...QUICK DOWNWARD TREND
HAS DEVELOPED IN THE GUIDANCE...WHICH SEEMS REASONABLE GIVEN THE
AMOUNT OF MID AND HIGH LEVEL CONVECTIVE DEBRIS EXPECTED INTO THE MID
AFTERNOON. OUR FCST HIGHS ARE MUCH MORE IN LINE WITH A GUIDANCE
BLEND SO THERE IS LITTLE CHANGE FROM THE PREVIOUS FCST IN THAT
REGARD. PREVIOUS THOUGHTS WERE ALSO THAT DEEP CONVECTION WOULD BE
HIGHLY DISCOURAGED DUE TO A FORMIDABLE CAPPING INVERSION. THE NEW
GUIDANCE SUGGESTS THAT IT MIGHT NOT BE SO UNBREAKABLE LATE IN THE
AFTERNOON. SOME OF THE CONVECTION ALLOWING MODELS DEVELOP A
THUNDERSTORM COMPLEX OVER THE CENTRAL APPALACHIANS THIS AFTERNOON
THAT PLOWS SOUTHWARD ACROSS THE PIEDMONT OF THE CAROLINAS THROUGH
EARLY EVENING. IF THAT WERE TO HAPPEN...THERE WOULD BE ENOUGH
DOWNDRAFT CAPE FOR SEVERAL SWATHS OF WIND DAMAGE. THE GFS IS STILL
BASICALLY DRY AND CAPPED...BUT THE NAM SUGGESTS NUMEROUS STORMS. IT
SEEMS THE MOST LIKELY SCENARIO IS FOR STORM COVERAGE TO REMAIN
LIMITED BECAUSE OF THE CAP THAT MIGHT NOT BE OVERCOME UNTIL AFTER
21Z...BUT WARY OF ANY BLOWUP OF CONVECTION OVER SRN WV/SW VA...THAT
WOULD REQUIRE A QUICK OVERHAUL OF PRECIP CHANCES. THE CONVECTION IF
IT DEVELOPS WILL MOVE OFF TO THE S IN THE MID EVENING. THEN
ATTENTION TURNS TO THE NEXT POSSIBLE UPSTREAM MCS APPROACHING FROM
THE NW TOWARD DAYBREAK THURSDAY. AT THIS POINT...IT APPEARS THAT IT
WOULD NOT REACH THE MTNS BEFORE SUNRISE...SO THE POP WILL BE KEPT
LOW AT THE VERY END OF THE PERIOD.
&&
.SHORT TERM /THURSDAY THROUGH SATURDAY/...
AS OF 245 AM WEDNESDAY...MODELS HAVE BEEN TRENDING A LITTLE BIT
SLOWER AND DEEPER WITH A SFC LOW...AS IT RACES ACRS PA INTO THE NRN
MID ATLANTIC COASTAL WATERS ON THURSDAY. THE BEST UPPER FORCING
LOOKS TO BE NEAR THIS SFC LOW...WHILE THE BEST INSTBY WILL BE OVER
THE TN VALLEY AND NRN GULF STATES. THE RESULT IS FOR A SORT OF GSP
SPLIT IN THE QPF RESPONSE...AND HENCE PERHAPS LESS OF A SEVERE
THREAT THAN EARLIER ANTICIPATED. THE ENVIRONMENT STILL LOOKS
FAVORABLE FOR SEVERE STORMS...MAINLY DURING THE AFTN HOURS AS A
FRONTAL BAND DEVELOPS/INTENSIFIES JUST OFF THE BLUE RIDGE AND
CROSSES THE PIEDMONT. STILL LOOKING AT 2000+ J/KG OF CAPE EAST OF
THE MTNS WITH BULK SHEAR OF 25-35 KTS. THE NEW DAY 2 CONVECTIVE
OUTLOOK KEEPS THE AREA IN A SLGT RISK...WITH A MODERATE RISK FOR
MORE WIDESPREAD WIND DAMAGE TO OUR NE CLOSER TO THE SFC LOW. WILL
ONLY MAKE MINOR TWEAKS TO THE HWO WORDING THIS MORNING. TEMPS WILL
PROBABLY BE ABLE TO WARM UP INTO THE LWR-MID 90S AHEAD OF THE
FRONT/CONVECTION EAST OF THE MTNS.
THE LINE OF CONVECTION AND COLD FRONT SHUD PUSH THRU THE SE CORNER
OF THE CWFA BY LATE EVENING...WITH DRY HIGH PRES BUILDING IN FOR
FRIDAY AND SATURDAY. POPS TAPER OFF THURSDAY EVENING...AND REMAIN
BELOW 15% THRU SATURDAY. TEMPS RETURN TO NEAR OR SLIGHTLY BELOW
NORMAL READINGS WITH A NOTICEABLE DROP IN HUMIDITY TOO.
&&
.LONG TERM /SATURDAY NIGHT THROUGH TUESDAY/...
AS OF 300 AM WEDNESDAY...MODELS IN GOOD AGREEMENT ON THE SRN CONUS
UPR RIDGE BREAKING DOWN SOMEWHAT BY THE END OF THE WEEKEND...WITH A
RETURN OF WLY UPR FLOW AND THE SHORTWAVE TRACK OVER THE CWFA FOR
EARLY NEXT WEEK. THE RIDGE WILL RE-ESTABLISH OVER THE SRN PLAINS BY
MIDWEEK...KEEPING THE ERN STATES IN PERSISTENT UPR TROFINESS. THIS
WILL LIKELY RESULT IN UNSETTLED WX RETURNING TO THE AREA FOR NEXT
WEEK...WITH SLIGHTLY ABOVE NORMAL TEMPS.
&&
.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
AT KCLT...VFR THROUGH THE FORECAST PERIOD. THE FCST SOUNDINGS FROM
MOST MODELS ARE CAPPED...SO ONLY A FEW HIGH BASED STRATOCU ARE
EXPECTED THROUGH MOST OF THE AFTERNOON...UNDERNEATH SOME MID AND
HIGH LEVEL CONVECTIVE DEBRIS MOVING DOWN FROM THE NW. WIND SHOULD
COME AROUND TO WSW BECAUSE OF A LEE TROF BY LATE MORNING. AND NOW HERE IS
THE CAVEAT...SOME OF THE CONVECTION ALLOWING MODELS SUGGEST A
COMPLEX OF THUNDERSTORMS WILL DEVELOP OVER SRN WV AND THEN PLOW
SOUTHWARD ACROSS THE PIEDMONT OF NC IN THE AFTERNOON...PERHAPS WITH
DECENT POTENTIAL FOR DAMAGING WIND GUSTS AND LARGE HAIL. IN THAT
CASE...THE CAP WOULD WORK TO THE ADVANTAGE OF THE STORMS BY HOLDING
THE LID ON THE DEEP CONVECTION AND STORING UP ALL THE ENERGY UNTIL
THE SQUALL LINE ARRIVES TO RELEASE IT. THIS IS ALL CONJECTURE.
RECENT RADAR IMAGERY SUGGESTS THIS MIGHT COME TO FRUITION. FOR NOW
THIS WILL BE INDICATED WITH A PROB30 FOR TSRA IN THE 21Z TO 23Z TIME
FRAME. WILL TRY TO GET A BETTER HANDLE ON THE CONVECTIVE THREAT THIS
MORNING. THE EVENING SHOULD BECOME UNEVENTFUL WITH LIGHT WIND AFTER
SUNSET.
ELSEWHERE...EXPECT MAINLY INCREASING HIGH LEVEL CLOUDS FROM MCS
DEBRIS THROUGH MORNING. THERE COULD BE SOME MVFR VISIBILITY IN THE
VICINITY OF KAVL AROUND SUNRISE. FOR THE AFTERNOON...SCENARIO IS
SIMILAR TO KCLT E OF THE BLUE RIDGE...WITH ISOLATED THUNDERSTORMS
POSSIBLE...BUT WILL NOT MENTION AT THIS TIME.
OUTLOOK...A COLD FRONT WILL BRING A GOOD CHANCE OF SHOWERS AND
THUNDERSTORMS TO THE REGION ON THURSDAY. HIGH PRESSURE WILL BUILD IN
BEHIND THE FRONT AND PRODUCE GENERALLY QUIET WEATHER AND VFR
CONDITIONS THROUGH THE WEEKEND.
CONFIDENCE TABLE...
12-18Z 18-24Z 00-06Z 06-12Z
KCLT HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KGSP HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAVL HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KHKY HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KGMU HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAND HIGH 100% HIGH 100% 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...ARK
NEAR TERM...LG/PAT
SHORT TERM...ARK
LONG TERM...ARK
AVIATION...PM
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NWS RAPID CITY SD
514 AM MDT WED JUN 12 2013
.SHORT TERM...TODAY THROUGH THURSDAY NIGHT
ISSUED AT 308 AM MDT WED JUN 12 2013
WATER VAPOR IMAGERY SHOWS A CUT OFF LOW ACROSS THE PACIFIC
NORTHWEST...AND WEAK RIDGING ACROSS THE NORTHERN HIGH PLAINS IN
THE WAKE OF THE SHORTWAVE NOW CROSSING EAST RIVER SD INTO
MINNESOTA. SURFACE ANALYSIS SHOWS HIGH PRESSURE FROM MONTANA TO
COLORADO.
HIGH PRESSURE WILL SLIDE INTO CENTRAL SOUTH DAKOTA TODAY BRINGING
QUIET WEATHER TO THE AREA FOR MUCH OF THE DAY TODAY. RETURN FLOW
WILL SET BACK UP FROM EASTERN MONTANA INTO NORTHEAST WYOMING AND
WESTERN SOUTH DAKOTA. TEMPERATURES IN THE 70S TO LOWER 80S ARE AGAIN
EXPECTED. UNSTABLE AIRMASS WILL REDEVELOP THIS AFTERNOON WITH MLCAPE
RANGING FROM 800 TO 1500 J/KG...AND WITH WEAKER CAPPING THAN
YESTERDAY. LOW LEVEL SHEAR WILL RAMP UP THROUGH THE LATE AFTERNOON
AND EVENING AS THE RETURN FLOW/LLJ STRENGTHENS. ISOLATED STORMS MAY
INITIATE OVER THE BLACK HILLS THIS AFTERNOON. OTHERWISE A SERIES OF
WAVES PUSHING INTO WESTERN WYOMING AND MONTANA WILL BRING
THUNDERSTORMS TOWARD THE BIG HORNS INTO CENTRAL MONTANA LATE THIS
AFTERNOON INTO TONIGHT. A DRYLINE WILL SET UP SOMEWHERE ACROSS
CENTRAL TO NORTHEASTERN WYOMING...AND THIS COULD BE THE FOCUS FOR
MORE CONVECTION. SUFFICIENT SHEAR WILL SUPPORT SUPERCELL DEVELOPMENT
LARGE HAIL AND DAMAGING WINDS POSSIBLE. THE BULK OF CONVECTION WILL
END BY 06Z...HOWEVER SOME LINGERING STORMS WILL BE POSSIBLE
OVERNIGHT WITHIN THE BAND OF THETA E ADVECTION AND LOW LEVEL JET
ACROSS WESTERN SOUTH DAKOTA.
STRENGTHENING ACTIVE SOUTHWEST FLOW ALOFT IS EXPECTED THURSDAY WITH
THE APPROACH OF THE NEXT TROUGH. SURFACE LOW WILL ALSO STRENGTHEN
NEAR THE MONTANA TO WYOMING BORDER LATE IN THE DAY ALONG A
BAROCLINIC ZONE. STRONG THETA E ADVECTION WILL CONTINUE ACROSS THE
CWA AHEAD OF THE SURFACE LOW. MOST LOCATIONS WILL SEE TEMPERATURES
REACH THE 80S AND DEWPOINTS REACHING THE UPPER 50S TO LOWER 60S. THE
SURFACE LOW WILL PUSH ACROSS EASTERN MONTANA THURSDAY AFTERNOON...AND
INTO THE DAKOTAS THURSDAY NIGHT. A SERIES OF UPPER WAVES WILL
COMBINE WITH A COLD FRONT CROSSING THE AREA TO BRING ANOTHER ROUND
OF THUNDERSTORMS. LOW LEVEL JET WILL CONTINUE ACROSS WESTERN SOUTH
DAKOTA...WHICH WILL AGAIN RESULT IN ENOUGH SHEAR FOR SUPERCELL
DEVELOPMENT. LARGE HAIL AND DAMAGING WINDS WILL BE THE MAIN THREATS
THURSDAY. CONVECTION WILL PUSH NORTHEASTWARD OVERNIGHT...CLEARING
THE CWA LATE THURSDAY NIGHT.
&&
.LONG TERM...FRIDAY THROUGH TUESDAY
ISSUED AT 308 AM MDT WED JUN 12 2013
MEAN WESTERN CONUS TROUGHING WILL CONTINUE IN THE
PERIOD...WITH TEMPORARY WESTERN TROUGH REMOVAL FRI-SUN PER TROUGH
KICKING BY AN ADVANCING NORTHERN PAC UPPER TROUGH. RETAINED LOW CHANCES
FOR POPS FRI OVER NE WY AND FAR SE FA GIVEN WITH THE ADVECTION OF
THE MAIN UPPER TROUGH INTO SOUTHERN CANADA. THIS UPPER TROUGH WILL
FRACTURE OVER SOUTHERN MB/SK WITH THE REMAINING VORT LOBE SHIFTING
SE SUN. MEAN RIDGING FAVORED EARLY NEXT WEEK AHEAD OF RE-INITIATED
WESTERN CONUS TROUGHING...SUPPORTING A WARMING TREND WITH INCREASING
CHANCES FOR SHRA/TS AS WEAK DISTURBANCES ADVECT EAST OUT OF THE MEAN
WESTERN CONUS TROUGH. BEST CHANCES FOR ANY PRECIP LOOKS TO REMAIN
OVER NE WY AND SOUTHERN PORTIONS OF THE FA...GIVEN HIGH TERRAIN
INITIATION AND LL THETA-E RIDGING. KEPT POPS FAIRLY LOW GIVEN
CONCERNS ON IMPULSE STRENGTH/TRACK/AND LL MOISTURE RECOVERY.
NOT MUCH CHANGES TO PREVIOUS POP NUMBERS...RETAINING LOW NUMBERS
IN MOST PERIODS. MONDAY COULD END UP DRY MOST PLACES...ESP IF
RIDGING IS DELAYED. OTHERWISE...A TRANSITION TO SW FLOW EARLY NEXT
WEEK SUPPORTS A SMALL UPTICK IN POPS. GENERALLY NORMAL TEMPS
EXPECTED IN THE PERIOD. DEGREE OF CAA BEHIND SUNDAY/S WAVE STILL
WAVERING IN GFS/ECMWF SOLUTIONS WITH POTENTIALLY COOLER NUMBERS
POSSIBLE. HAVE SIDED SLIGHTLY BELOW NORMAL FOR MONDAY ATTM.
OTHERWISE...WARMING TREND LIKELY BEYOND MONDAY GIVEN EASTERN
TRANSLATION OF THE NEXT RIDGE.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 509 AM MDT WED JUN 12 2013
IFR/LIFR CIGS WILL BE FOUND FROM NE WY NEAR W43...SE TO RAP AND IN
SURROUNDING AREAS NEAR THE BH. FLOW WILL VEER EASTERLY WHICH MAY
ALLOW CIGS TO PERSIST INTO EARLY AFTERNOON ALONG THE EASTERN BH
FOOTHILLS INCLUDING RAP. OTHERWISE...VFR CONDITIONS ARE EXPECTED
ACROSS THE REMAINDER OF THE REGION AS WEAK SFC HIGH PRESSURE
SHIFTS SOUTHEAST ACROSS THE CENTRAL DAKOTAS. ANOTHER MID LEVEL
IMPULSE IN SW FLOW MAY SUPPORT AN ISOLD TS LATE THIS AFTERNOON AND
OVERNIGHT FROM NE WY INTO NW SD.
&&
.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...NONE.
&&
$$
SHORT TERM...13
LONG TERM...JC
AVIATION...JC
AREA FORECAST DISCUSSION...UPDATED
NWS MILWAUKEE/SULLIVAN WI
1037 AM CDT WED JUN 12 2013
.UPDATE...THE REMNANTS OF AN MCS CONTINUE TO WEAKEN WHILE MOVING
THROUGH THE EASTERN FORECAST AREA. COULD SEE A FEW SHOWERS OR
STORMS DEVELOP LATE MORNING INTO EARLY AFTERNOON...BUT OTHERWISE
IT LOOKS PRETTY QUIET UNTIL LATER IN THE AFTERNOON.
THE MAIN ISSUE FOR TODAY IS THE POTENTIAL FOR SEVERE
WEATHER...WHICH WILL DEPEND ON EXACTLY WHERE THE WARM FRONT IS
THIS AFTERNOON AND THUS THE BETTER SURFACE BASED INSTABILITY.
SHOWERS AND STORMS SEEM LIKELY EVEN NORTH OF THE FRONT...WITH
AROUND 1000 J/KG OF ELEVATED CAPE. PLENTY OF MOISTURE TO WORK WITH
AS WELL...WITH PRECIPITABLE WATER VALUES PUSHING 2 INCHES. THIS
COULD RESULT IN PRETTY HEAVY RAINFALL WITHIN STORMS.
LOOKING AT LATEST MODELS...THE BULK OF SOLUTIONS KEEP THE WARM
FRONT ALONG OR SOUTH OF THE WI/IL BORDER. EARLIER HRRR RUNS PUSHED
THE WARM FRONT UP TO AROUND MADISON...BUT THE LATEST RUN IS
FARTHER SOUTH SIMILAR TO OTHER MODELS. THE LATEST NAM TAKES
STRONGER SEVERE PARAMETERS INTO THE SOUTHWEST FORECAST AREA THIS
AFTERNOON...SHIFTING IT SOUTH BY EVENING. THOUGH BEST SEVERE
THREAT MAY STAY MAINLY TO THE SOUTH...STILL COULD SEE STRONG TO
SEVERE STORMS ACROSS SOUTHERN WISCONSIN. WILL HAVE THE ELEVATED
INSTABILITY...MAYBE SOME SURFACE BASED IF AREA OF CLEARING TO THE
WEST CAN SLIDE OVER ACROSS SRN WI. ALSO...0-6 KM BULK SHEAR WILL
BE ON THE ORDER OF 40-50 KT. WILL HAVE TO MONITOR THE WARM FRONT
POSITION AND THE AMOUNT OF HEATING THAT OCCURS LATE MORNING INTO
THE AFTERNOON TO CONTINUE TO ASSESS THE SEVERE THREAT.
&&
.AVIATION/18Z TAFS/...COULD SEE A FEW SHOWERS AND STORMS LATE
MORNING INTO THE AFTERNOON...BUT OTHERWISE LOOKS PRETTY QUIET
UNTIL MID OR LATE AFTERNOON AND INTO THE EVENING. EXPECTING
WIDESPREAD SHOWERS AND STORMS TO DEVELOP BY LATER TODAY...WITH A
THREAT FOR SEVERE STORMS. THE BEST CHANCE FOR SEVERE WEATHER LOOKS
TO BE TOWARD AND SOUTH THE ILLINOIS BORDER...BUT THINK THERE WILL
BE ENOUGH ELEVATED INSTABILITY AND SHEAR FOR POTENTIAL STRONG TO
SEVERE STORMS ACROSS SOUTHERN WISCONSIN. CONVECTION SHOULD WIND
DOWN BY LATE EVENING...WITH DRY WEATHER EXPECTED OVERNIGHT AND
TOMORROW AS HIGH PRESSURE MOVES IN.
PREVAILING VFR EXPECTED INTO THE AFTERNOON...WITH LOWER VSBYS
POSSIBLE IN MODERATE TO HEAVY RAINFALL LATER TODAY. COULD SEE
BRIEFLY LOWER CIGS BEHIND EXITING LOW PRESSURE THIS EVENING...BUT
SHOULD SEE A RETURN TO VFR OVERNIGHT AS DRIER AIR MOVES IN.
&&
.PREV DISCUSSION... /ISSUED 250 AM CDT WED JUN 12 2013/
SHORT TERM...
TODAY AND TONIGHT...FORECAST CONFIDENCE MEDIUM TO HIGH
ENTRANCE REGION OF 90 KNOT 250 MB JET MAX OVER THE GREAT LAKES IS
ACROSS CENTRAL/SOUTHERN WISCONSIN TODAY BEFORE AN UPPER LEVEL TROUGH
AXIS WITH A TRAILING 90 KNOT JET MAX PUSHES ACROSS NORTHERN ILLINOIS
TONIGHT.
MAINLY WEAK UPPER DIVERGENCE EARLY THIS MORNING BEFORE AN AREA OF
STRONG UPPER DIVERGENCE MOVES ACROSS SOUTHERN WISCONSIN LATER THIS
MORNING. HOWEVER THIS APPEARS TO HAVE SOME CONVECTIVE FEEDBACK FROM
THUNDERSTORMS OVER NORTHWEST IOWA THAT THE NAM PUSHES EAST ACROSS
WISCONSIN. THIS IS ALSO SEEN AS AN AREA OF CYCLONIC VORTICITY AT
500 MB AHEAD OF THE MAIN MID LEVEL SHORTWAVE THAT MOVES ACROSS
NORTHERN ILLINOIS/SOUTHERN WISCONSIN THIS AFTERNOON AND EVENING.
WHILE THE MAIN 700 MB THERMAL RIDGE MOVES ACROSS NORTHERN
ILLINOIS...SOUTHERN WISCONSIN WILL BE IN A MODERATE TEMPERATURE
GRADIENT. WEAK/MODERATE 700 MB UPWARD MOTION EXISTS ACROSS SOUTHERN
WISCONSIN WITH A STRONGER 15 MICROBAR/SEC AREA LATE THIS AFTERNOON
WITH THE MAIN MID LEVEL TROUGH. THE STRONGER 850 MB/700 MB WINDS
SET UP ACROSS NORTHERN ILLINOIS. WEAK TO MODERATE 850 MB MOISTURE
CONVERGENCE OCCURS OVER SOUTHERN WISCONSIN THROUGH THE MORNING WITH
A STRONGER AREA WITH THE SHORTWAVE THIS AFTERNOON.
PRECIPITABLE WATER VALUES REACH ALMOST 2 INCHES BY EARLY EVENING
OVER MUCH OF SOUTHERN WISCONSIN.
THE RAP AND MOST OF THE MESOSCALE MODELS BRING SCATTERED TO NUMEROUS
SHOWERS/THUNDERSTORMS THIS MORNING WITH THE MAIN MCS MOVING ACROSS
NORTHERN ILLINOIS AND PORTIONS OF SOUTHERN WISCONSIN LATER THIS
AFTERNOON. THIS APPEARS REASONABLE.
THE 04Z HRRR TRIES TO DEVELOP THE NORTHWEST IOWA MCS BUT WEAKENS IT
OVER SOUTHERN WISCONSIN THIS MORNING...AND TAKE THE SOUTH DAKOTA MCS
AND WEAKENS IT INTO A MORE WEST TO EAST AREA OF SHOWERS AND
THUNDERSTORMS.
WHAT MAY HAPPEN IS MORE OF A HEAVY RAIN EVENT WITH THE AFTERNOON MCS
FORMED BY THE SYNOPTIC SHORTWAVE AND ASSOCIATED SURFACE LOW. THE
SPC DAY ONE OUTLOOK HAS A MODERATE RISK JUST SOUTH OF THE WISCONSIN
BORDER WITH A SLIGHT RISK OVER SOUTHERN WISCONSIN. THIS AGREES WITH
THE NEW 00Z CIPS ANALOGS THAT PLACE THE MAJORITY OF THE 30 KNOT WIND
PROBABILITIES AND SEVERE REPORTS TO THE SOUTH OF WISCONSIN...WITH A
FEW WIND SEVERE WIND REPORTS IN FAR SOUTHERN WISCONSIN.
THE SHORTWAVE DROPS INTO NORTHERN INDIANA AFTER MIDNIGHT TONIGHT.
EXPECT A SURGE OF NORTH WINDS ESPECIALLY DOWN LAKE MICHIGAN LATE
THIS EVENING AND TONIGHT.
THURSDAY THROUGH FRIDAY...FORECAST CONFIDENCE HIGH.
A HIGH PRESSURE RIDGE WILL BE MOVING ACROSS THE UPPER MIDWEST AND
GREAT LAKES REGION DURING THIS PERIOD. EXPECT SUNSHINE...LOWER
DEWPOINTS AND LIGHT NORTH TO EAST WINDS. HIGHS WILL BE AROUND
CLIMATOLOGICAL NORMAL INLAND FROM THE LAKE IN THE MID/UPPER 70S.
LONG TERM...
FRIDAY NIGHT AND SATURDAY...FORECAST CONFIDENCE MEDIUM.
THE UPPER LEVEL RIDGE WILL BE BREAKING DOWN INTO A MORE ZONAL FLOW
PATTERN OVER THE UPPER MIDWEST. A SHORTWAVE TRACKING ALONG THIS
RIDGE WILL MOVE ACROSS IA/IL LATE FRI NIGHT INTO SAT MORNING. A
CLUSTER OF THUNDERSTORMS/MCS SEEMS THE LIKELY MODE OF CONVECTION
WITH THIS FEATURE ON THE NOSE OF THE LOW LEVEL JET. SOUTHERN WI MAY
BE ON THE NORTHERN FRINGE OF THE STRONGER STORMS AND JUST GET THE
RAIN AND ELEVATED THUNDERSTORMS IF THE 00Z ECMWF MODEL SOLUTION PANS
OUT. THE GFS MODEL IS MAINTAINING A MORE NORTHERLY TRACK WHICH WOULD
IMPACT THE ENTIRE MKX FORECAST AREA WITH SHOWERS AND
STORMS...POSSIBLY STRONG.
ANOTHER ROUND OF SHOWERS AND STORMS WILL BE POSSIBLE SATURDAY NIGHT
WITH AN UPPER LEVEL SHORTWAVE TROUGH AND A WEAK SURFACE COLD
FRONT...BUT THIS HAS A PRETTY GOOD CHANCE OF REMAINING SOUTH OF THE
WI/IL BORDER.
SUNDAY THROUGH MONDAY...FORECAST CONFIDENCE MEDIUM.
AN UPPER LEVEL TROUGH WILL SWING DOWN ACROSS THE GREAT LAKES REGION
SUNDAY AND MONDAY. THIS WILL BRING SHOWERS AND THUNDERSTORMS TO MUCH
OF WISCONSIN AHEAD OF AND ALONG A COLD FRONT. THE 00Z ECMWF IS ABOUT
12 HOURS SLOWER THAN THE GFS WITH THIS SYSTEM.
TUESDAY THROUGH WEDNESDAY...FORECAST CONFIDENCE MEDIUM.
ONCE THAT SYSTEM CLEARS WISCONSIN...SURFACE HIGH PRESSURE WILL
SETTLE OVER THE GREAT LAKES REGION AS A RELATIVELY WEAK UPPER LEVEL
RIDGE BUILDS IN OVER THE CENTER OF THE COUNTRY. OVERALL THE WEATHER
WILL BE QUIET FOR SOUTHERN WI...BUT THERE WILL PROBABLY CONTINUE TO
BE A SLIGHT CHANCE FOR THUNDERSTORMS MENTIONED IN THE FORECAST. THIS
IS DUE TO POSSIBLE WEAK RIPPLES IN THE UPPER LEVEL NORTHWEST FLOW
PATTERN OUT AHEAD OF THAT UPPER RIDGE.
AVIATION/12Z TAFS/...
MAINLY VFR INITIALLY WITH SCATTERED SHOWERS/ISOLATED THUNDERSTORMS.
SOME MVFR/IFR CIGS VISIBILITIES ARE POSSIBLE AS THE SCATTERED
SHOWERS/ISOLATED THUNDERSTORMS BECOME MORE NUMEROUS THIS AFTERNOON.
SOME STORMS COULD BE SEVERE. AS A LOW MOVES ACROSS NORTHERN
ILLINOIS THIS AFTERNOON THE MVFR/IFR CIGS/VSBYS WILL BECOME MORE
NUMEROUS. THE THUNDERSTORM CHANCES WILL END TONIGHT BY MIDNIGHT AS
THE LOW MOVES ACROSS NORTHERN INDIANA.
MARINE...
SOME CONCERN OF FOG TODAY. WINDS WILL BE LIGHT OVER THE LAKE
AND THE PRESENT AIR MASS IS MOIST. GIVEN THE LIGHT WINDS THAT WILL
VEER FROM THE NORTH TO THE EAST NORTHEAST AND THE AFOREMENTIONED AIR
MASS...INCLUDED PATCHY DENSE FOG IN THE NEARSHORE ZONES. NOT ENOUGH
CONFIDENCE AT THIS TIME TO GO WITH A DENSE FOG ADVISORY. THEN
CONCERN IS INCREASING THUNDERSTORM CHANCES. SOME MAY BE SEVERE.
BRISK NORTH WINDS ON TONIGHT COULD REACH SMALL CRAFT CRITERIA.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...NONE.
&&
$$
UPDATE...DDV
TODAY/TONIGHT AND AVIATION/MARINE...HENTZ
THURSDAY THROUGH TUESDAY...MRC
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
641 AM CDT WED JUN 12 2013
.SHORT TERM...(TODAY THROUGH THURSDAY)
ISSUED AT 318 AM CDT WED JUN 12 2013
MAIN CONCERN FOR TODAY INTO THIS EARLY EVENING WILL BE SEVERE
THUNDERSTORM THREAT ACROSS THE SOUTH.
WATER VAPOR IMAGERY/RAP 500MB HEIGHT FIELD SHOWS A VIGOROUS
SHORTWAVE TROUGH MOVING OUT OF MT/WY INTO WESTERN ND/SD/NE. SURFACE
MAP AS OF 2 AM HAD AN AREA OF LOW PRESSURE ALONG THE KS/NE BORDER
WITH A WARM FRONT EXTENDING ENE ALONG I-80 IN IA AND IL. 850MB
MOISTURE TRANSPORT/ISENTROPIC LIFT AHEAD OF THE LOW AND OVER THE
WARM FRONT WAS PRODUCING SCATTERED ELEVATED SHRA/TS ACROSS OUR
FORECAST AREA...WITH A MORE INVIGORATED N-S LINE OF STORMS ACROSS
CENTRAL SD WHICH WAS HEADED EAST AROUND 50KT. RAP CORFIDI VECTORS
TAKE THIS COMPLEX OF STORMS DUE EAST AT 55-65KT THIS MORNING...WHICH
WOULD BRING IT INTO OUR AREA IN THE 7-9 AM TIME FRAME. MEANWHILE...A
NEW COMPLEX OF THUNDERSTORMS WERE FIRING ACROSS NORTHWEST
IA...MOVING TOWARD THE EAST. THIS CONVECTION WAS ROOTED A BIT CLOSER
TO THE CAPE POOL JUST NORTH OF THE 925-850MB WARM FRONT. A COUPLE
OBS IN SD WHERE THIS LINE PASSED RECORDED 43/48KT. HOWEVER...WRF
MODELS...NAMELY THE 12.00Z NSSL WRF WHICH SEEMS TO HAVE THE BEST
HANDLE ON THE CONVECTION RIGHT NOW...HAS THIS CONVECTION DECAYING AS
IT MOVES INTO THE AREA IN THE 5-8AM TIME FRAME. WITH 0-3KM BULK
SHEAR IN THE 40-50KT RANGE AND 0-3KM ML MUCAPE HOVERING IN THE
1000-2000J/KG...WILL HAVE TO WATCH THIS ONGOING CONVECTION CAREFULLY
FOR A SEVERE WIND THREAT EARLY THIS MORNING.
THERE THEN SEEMS TO BE A BREAK IN THE ACTION FROM MID-MORNING UNTIL
EARLY AFTERNOON BEFORE THE MID-LEVEL TROUGH AND SURFACE LOW MOVE
ACROSS EASTERN IA IN THE 18Z-21Z TIME FRAME. THIS TROUGH/STEEPENING
MID LEVEL LAPSE RATES THEN INTERACTS WITH 2000-3500J/KG 0-1KM ML
MUCAPE POOL IN PLACE SOUTH OF I-90 TO FIRE VIGOROUS/DEEP
CONVECTION. COOLING MID LEVEL/STEEPER LAPSE RATES AND 0-3KM BULK
SHEAR IN THE 20-40KT RANGE WILL SUPPORT A SEVERE HAIL/WIND THREAT
SOUTH OF I-90. AND...WITH THE JUXTAPOSITION OF THE LOW/WARM FRONT
PRODUCING FAVORABLE 0-3KM SRH...CANNOT RULE OUT A TORNADIC THREAT
ACROSS PORTIONS OF NORTHEAST IA INTO FAR SOUTHWEST WI...NAMELY
FAYETTE AND CLAYTON COUNTIES IN NORTHEAST IA AND GRANT COUNTY IN WI.
LOCALIZED FLOODING IS ALSO A CONCERN WITH THIS CONVECTION AS
PRECIPITABLE WATER VALUES HOVER IN THE 1.5 TO 2 INCH RANGE. SEE
HYDROLOGY SECTION BELOW FOR FURTHER DETAILS ON HEAVY RAIN POTENTIAL
AND IMPACTS. PLAN ON THE LOW AND ASSOCIATED CONVECTION TO MOVE
SOUTHEAST OF THE REGION AROUND MIDNIGHT TONIGHT. HIGH PRESSURE THEN
STARTS NOSING IN AFTER MIDNIGHT FROM THE NORTHERN PLAINS FOR
CLEARING SKIES.
HIGH PRESSURE WILL BE IN CONTROL ON THURSDAY WITH PLEASANT
TEMPERATURES IN THE 70S AND LOWER HUMIDITY LEVELS.
.LONG TERM...(THURSDAY NIGHT THROUGH TUESDAY)
ISSUED AT 318 AM CDT WED JUN 12 2013
HIGH PRESSURE REMAINS IN CONTROL ACROSS THE AREA THURSDAY NIGHT
THROUGH FRIDAY MORNING FOR A CONTINUED DRY RESPITE. BY FRIDAY
AFTERNOON THOUGH...A TROUGH OF LOW PRESSURE OVER THE PLAINS BEGINS TO
SHOVE MOISTURE BACK INTO THE AREA...MAINLY WEST OF THE MISSISSIPPI
RIVER FOR A CHANCE OF SHOWERS/ISOLATED THUNDER. FOR FRIDAY NIGHT
THROUGH SATURDAY EVENING...LOOK FOR LOW PRESSURE OVER CANADA TO SEND
A COLD FRONT THROUGH THE AREA. THIS WILL PRODUCE THE LIKELIHOOD OF
SHOWERS AND THUNDERSTORMS. WILL NEED TO WATCH FOR THE POSSIBILITY OF
SEVERE WEATHER GIVEN 0-1KM ML MUCAPE IN THE 1500-3500J/KG AND MODEST
AMOUNT OF 0-3KM BULK SHEAR. LINGERING MID-LEVEL TROUGH/FAIRLY STEEP
LAPSE RATES ENOUGH TO WARRANT A LOWER-END SHRA/TS CHANCE SUNDAY
THROUGH MONDAY. NORTHWEST FLOW AND ANOTHER WEAK MID-LEVEL TROUGH IN
THIS FLOW PRODUCE ANOTHER SHRA/TS CHANCE ON TUESDAY. OTHERWISE...
LOOKS LIKE TEMPERATURES WILL BE RIGHT AROUND NORMAL THROUGH THE
PERIOD...MAINLY IN THE 70S.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 641 AM CDT WED JUN 12 2013
AN AREA OF LIGHT TO MODERATE RAINFALL IS MOVING ACROSS THE REGION
BUT SHOULD CLEAR BOTH RST AND LSE OVER THE NEXT FEW HOURS.
CONDITIONS ARE VFR UNTIL YOU GO FURTHER SOUTH WHERE A CLUSTER OF
THUNDERSTORMS IS TRACKING TO THE EAST ACROSS NORTHEAST IOWA.
MAINLY HIGH LEVEL CLOUD COVER TO CONTEND WITH BEHIND THIS SYSTEM
WITH VISIBILITY REMAINING VFR.
THUNDERSTORMS ARE EXPECTED TO REDEVELOP ACROSS THE REGION TOWARD
MID AFTERNOON AND TRACK TO THE SOUTH BY EARLY EVENING. VISIBILITY
WILL LIKELY DROP TO AT LEAST MVFR BUT COULD DROP TO IFR AT TIMES.
AFTER THE STORMS DROP TO THE SOUTHEAST BY THIS EVENING...EXPECT
THAT SKIES WILL CLEAR OUT AND WINDS WILL SHIFT AROUND TO THE
NORTHWEST.
&&
.HYDROLOGY...TODAY INTO THIS EVENING
ISSUED AT 318 AM CDT WED JUN 12 2013
FOR AREAS MAINLY ALONG AND SOUTH OF I-90...EXPECTING RAINFALL
AMOUNTS FROM TODAY INTO THIS EVENING IN THE 0.75 TO 1.25 INCH RANGE
WITH THE POSSIBILITY OF LOCALLY HIGHER AMOUNTS IN THUNDERSTORM
ACTIVITY. GIVEN THE WET SOILS IN PLACE...PLAN ON SOME RUNOFF ISSUES
WITH PONDING OF WATER AND SOME SIGNIFICANT WITHIN BANK RIVER RISES.
ANY LONGER DURATION/HIGHER RAINFALL RATES WOULD INCREASE THE
FLOODING POTENTIAL. STAY TUNED.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...DAS
LONG TERM....DAS
AVIATION...HALBACH
HYDROLOGY....DAS
AREA FORECAST DISCUSSION
NWS TALLAHASSEE FL
339 PM EDT Wed Jun 12 2013
.NEAR TERM [Through Tonight]...
Isolated to scattered thunderstorms will develop this afternoon,
mainly between I-10 and the coast. This is where the low level
convergence and MLCAPE will be greatest as the slow-moving sea
breeze fronts interact with orthogonal horizontal convective rolls.
Most of the cumulus clouds will be unable to grow substantially
because of the very dry air above 700 mb, but in a few spots (where
mesoscale forcing is strongest and CAPE/boundary layer moisture is
maximized) there could be a strong enough updraft to support a pulse
strong/severe storm. Isolated storms may develop in south GA this
evening (as indicated by some of the Convection Allowing Models like
the HRRR and our local WRF), as the FL sea breeze fronts
accelerate inland.
Temperatures were already in the 90s early this afternoon, and
will top out in the mid to upper 90s. Heat index values may reach
105 deg at a few inland locations. Lows tonight will be in the lower
to mid 70s, with plenty of humidity.
&&
.SHORT TERM [Thursday Through Friday Night]...
Despite the upper level ridging over the U.S. which has been keeping
the weather hot and dry (with the exception of afternoon sea-breeze
showers and thunderstorms near the coast), the pattern gets a little
more interesting as a short wave trof digs down the east side of the
ridge. The shortwave trof will enhance surface pressure drops and
upper level winds (and thus shear). A line of showers and
thunderstorms along a weak frontal boundary from the surface low is
expected to dip into our area Thursday night. There is some model
disagreement as to whether or not these storms will dip as far south
as our forecast area, but if they do the model MLCAPE values of
around 3000 J/kg and 0-6 km bulk shear of around 30 kts suggest that
they will be strong to severe storms. SPC has our AL and GA
counties in a slight risk for severe thunderstorms in the day 2
outlook. The bulk shear is a little low for supercell development,
but stronger individual cells may form along the line, especially
with such a high amount of instability. Looking at the Fri 00Z
model soundings, there are conditionally unstable lapse rates
through most of the profile and drier air has made its way in the
mid levels thanks to the high pressure we`ve been under. CAPE
contribution in the -10 to -30 C range is around 1000 J/kg and
DCAPE is 1500-2000 J/kg. These parameters suggest that there is a
threat for both severe winds (58+ MPH) and 1" hail. Lower level
vorticity and wind shear is higher to the north of our area, but a
tornado from a stronger cell can`t be ruled out either.
Highs tomorrow will be in the upper 90s, similar to today, but may
be a little lower Thursday depending on the cloudiness ahead of the
line of storms and the timing of the storms themselves. Lows
Thursday night will be in the low-mid 70s, a little warmer due to
higher cloud cover and rain chances, but return to the lower 70s
Friday night.
&&
.LONG TERM [Saturday through Tuesday]...
After the potential system passes Thursday night, high pressure
aloft and at the surface will build eastward and be the main
synoptic scale influence on the forecast area`s weather through
Tuesday. On Tuesday, another shortwave will propagate through the
upper level ridge and set up a pattern similar to Thursday night
(see short term). Highest PoPs in the forecast period are Tuesday
and Wednesday. Expecting highs in the 90s and lows in the low 70s
through the long term period.
&&
.AVIATION [Through 18Z Thursday]...
Widely scattered TSRA will develop this afternoon from I-10 to the
coast, so there could be a brief period of TSRA at KTLH and KECP.
Isolated TSRA may develop in south GA this evening, but the PoP at
KVLD and KABY is only 20%. Otherwise, VFR conditions are likely
outside of any isolated TSRA.
&&
.MARINE...
A low pressure system to our northwest will dip ito the SE US and
increase chances of showers and thunderstorms Thursday night and
Friday. Although most of the storms will be inland, some stronger
storms are expected, so there is the possibility of brief periods
of cautionary to advisory winds as these storms pass through.
Otherwise, winds and seas will remain below headline criteria
through the period.
&&
.FIRE WEATHER...
Red Flag conditions are not expected for the remainder of the work
week. Dispersion values may climb above 75 Thursday afternoon, from
a combination of strong vertical mixing and increasing winds aloft.
&&
.HYDROLOGY...
The Ochlockonee River at Thomasville is in action stage and may
rise slightly with rain tomorrow night, but it is not expected to
reach minor flood stage. MMEFS shows no sites are forecast to
reach flood stage in the near future. Although there is potential
for some severe thunderstorms Thursday night, WPC QPF for our area
is 0.25" or less and is not expected to cause significant rises on
area rivers.
&&
.PRELIMINARY POINT TEMPS/POPS...
Tallahassee 95 73 96 75 95 / 20 10 20 20 30
Panama City 90 76 91 78 92 / 30 10 10 20 20
Dothan 97 75 99 74 95 / 10 10 10 30 10
Albany 97 75 99 74 93 / 10 20 10 40 10
Valdosta 99 73 97 74 93 / 10 20 20 30 30
Cross City 93 72 92 73 92 / 20 10 20 20 30
Apalachicola 89 76 89 77 91 / 20 10 10 20 30
&&
.TAE WATCHES/WARNINGS/ADVISORIES...
FL...None.
GA...None.
AL...None.
GM...None.
&&
$$
NEAR TERM...Fournier
SHORT TERM...Moore
LONG TERM...Moore
AVIATION...Fournier
MARINE...Moore
FIRE WEATHER...Fournier
HYDROLOGY...Moore
AREA FORECAST DISCUSSION...UPDATED
NWS PEACHTREE CITY GA
155 PM EDT WED JUN 12 2013
.UPDATE...
I HAVE ADJUSTED SOME OF THE GRIDS FOR TODAY...MAINLY POPS/WEATHER.
MODEL SOUNDINGS HAVE BEEN INDICATING THAT THE MID-LEVEL CAP WOULD
REMAIN STRONGLY IN PLACE OVER NORTH AND CENTRAL GEORGIA THROUGH
TODAY. THE 12Z SOUNDING FROM KFFC SHOWS THE MID-LEVEL CAP TO BE
SIGNIFICANTLY WEAKER THAN EXPECTED WITH ONLY MINIMAL CIN IN THE
VICINITY OF THE LFC. STILL...WE ARE UNDER THE EASTERN EDGE OF THE
UPPER-LEVEL RIDGE AND SOME INHIBITION WILL LIKELY CONTINUE THROUGH
TODAY. IF ANY STORMS MANAGE TO BREAK THROUGH THIS AFTERNOON...
INSTABILITY IS MODERATE WITH CAPE AROUND 2000 J/KG AND LI/S IN THE -4
TO -6 DEGREE RANGE SO AN ISOLATED STRONG STORM OR TWO WOULD NOT BE
IMPOSSIBLE. NO SIGNIFICANT CHANGES MADE TO THE REMAINDER OF THE GRIDS
AS CURRENT FORECAST TRENDS LOOK PRETTY GOOD.
&&
.PREV DISCUSSION... /ISSUED 733 AM EDT WED JUN 12 2013/
PREV DISCUSSION...
SHORT TERM /TODAY THROUGH THURSDAY/...
/ISSUED 405 AM EDT WED JUN 12 2013/
ANOTHER HOT DAY ACROSS THE CWA AS THE AREA REMAINS UNDER THE EASTERN
EDGE OF AN UPPER LEVEL RIDGE. SOME DECENT UNCERTAINTY IN THE POP
FORECAST FOR TODAY. GFS SHOWS A STRONG VORT MAX ROUNDING THE UPPER
LEVEL RIDGE AND BRINGS IT INTO NORTH GEORGIA BY MID MORNING. GFS
ISNT GENERATING MUCH IN TERMS OF PRECIP WITH IT THOUGH ACROSS THE
CWA. NAM SHOWS SOME REFLECTION OF A SHORTWAVE BUT IS WEAKER AND
GENERALLY FURTHER EAST. EVEN HARDER TO PICK OUT THE FEATURE IN THE
ECMWF. DESPITE THIS THOUGH...ECMWF AND NAM ARE THE HIGHEST IN TERMS
OF PRECIP CHANCES ACROSS NORTH GEORGIA TODAY. HRRR IS PICKING UP ON
SOME ACTIVITY IN NORTH GEORGIA ASSOCIATED WITH THIS. FOR THE
FORECAST TRIED TO MEET IN THE MIDDLE AND HAVE SHOWN SLIGHT CHANCE OF
SHOWERS AND THUNDERSTORMS ACROSS THE NORTH. LEE SIDE TROUGH APPEARS
IT SHOULD BE JUST SOUTH OF THE CWA THIS AFTERNOON AND IF SOMETHING
WERE TO DEVELOP...THINK IT SHOULD BE ALONG THIS BOUNDARY...SO KEPT
MENTION OF POPS OUT OF CENTRAL GEORGIA.
THURSDAY IS THE BETTER CHANCE OF RAIN IN THE SHORT TERM AS A STRONG
SHORTWAVE MOVES FROM THE OHIO VALLEY INTO THE MID ATLANTIC AND A
COLD FRONT MOVES INTO GEORGIA. MODELS ARE IN GOOD AGREEMENT WITH THE
COLD FRONT MOVING INTO THE NORTH THURSDAY MORNING AND INTO CENTRAL
GEORGIA BY THE EVENING. DECENT INSTABILITY WITH THE SYSTEM WITH THE
GFS SHOWING ML CAPE AROUND 2000 J/KG. LL SHEAR IS NON-ZERO WITH
AROUND 20KTS ACROSS CENTRAL GEORGIA. WITH THE INSTABILITY...A
BOUNDARY TO FOCUS ON AND UPPER LEVEL SUPPORT...ISOLD SEVERE STORMS
ARE POSSIBLE ON THURSDAY WITH THE MAIN THREATS BEING WIND AND HAIL.
TOTAL RAINFALL AMOUNTS SHOULD BE MINIMAL...AROUND A QUARTER INCH OR
LESS WITH LOCALLY HIGHER AMOUNTS IN SOME OF THE THUNDERSTORMS.
BOTH AHN AND ATL SAW THEIR FIRST 90 DEGREE DAY FOR THE YEAR
YESTERDAY AND ALL OF NORTH AND CENTRAL GEORGIA IS EXPECTED TO REACH
THE LOW TO MID 90S AGAIN TODAY EXCEPT FOR THE MOUNTAINS. EVEN WITH
THE FRONT EXPECTED ON THURSDAY...MOST PLACES WILL HAVE TIME AHEAD OF
THE RAIN TO REACH THE 90S AGAIN. SOME OF CENTRAL GEORGIA WILL REACH
HEAT INDICES OF 100-102 THIS AFTERNOON WHICH FALLS SHORT OF A HEAT
ADVISORY /105 DEGREES OR GREATER HEAT INDICES FOR TWO CONSECUTIVE
DAYS/...BUT IT WILL STILL BE HOT AND FOLKS SHOULD KEEP THIS IN MIND
WHEN WORKING OUTSIDE AS ITS EXPECTED TO BE THE HOTTEST DAY OF THE
SEASON SO FAR.
11
LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
/ISSUED 405 AM EDT WED JUN 12 2013/
A COLD FRONT WILL BE CLOSE TO CENTRAL GA AND MOVING S STARTING
THURSDAY NIGHT WITH POTENTIAL FOR SEVERE STORMS ASSOCIATED. THE
FRONT EXITS THE FORECAST AREA LATER THURSDAY NIGHT WITH THE GFS THE
FASTEST...THE NAM NEXT AND THE EUROPEAN THE SLOWEST.
PRECIP CHANCES MOST LIKELY WILL HAVE ENDED FOR FRIDAY ALTHOUGH THE
EUROPEAN HOLDS ONTO CHANCES OVER CENTRAL GA. SATURDAY IS DRY AS HIGH
PRESSURE ALOFT OVER THE LOWER MS VALLEY HELPS FOR HOLD ANY
CONVECTION AT BAY...HOWEVER NW FLOW ALOFT IS OVER THE AREA BUT
APPEARS TO HAVE ONLY MINIMAL MOISTURE. SUNDAY APPEARS ONE OF THOSE
DAYS WHERE YOU COULD GO EITHER WAY WITH 20 PERCENT POPS OVER THE NW
HALF OR SO OF THE AREA AS THE UPPER RIDGE FLATTENS AND SOME
INSTABILITY DEVELOPS WITH MINIMAL MOISTURE. FOR NOW WILL JUST HOLD
ONTO 10 PERCENT ACROSS THE NW. THE SOUTHERN EDGE OF THE WESTERLIES
RETURN FOR MONDAY AND TUESDAY WITH INCREASED MOISTURE AND
INSTABILITY ACROSS THE AREA AND THE POSSIBILITY FOR SHORT WAVES TO
ENHANCE THE POTENTIAL FOR SCATTERED SHOWERS AND THUNDERSTORMS. A
WEAK COLD FRONT MAY GET INTO N GA FOR WEDNESDAY.
BDL
&&
AVIATION...
18Z UPDATE...
VFR CONDITIONS SHOULD PREDOMINATE THROUGH THIS FORECAST PERIOD
OUTSIDE OF ISOLATED TO SCATTERED CONVECTIVE ACTIVITY. SCATTERED
AREAS OF MVFR...WITH LOCAL IFR...VISIBILITIES ARE EXPECTED AGAIN
THURSDAY MORNING BETWEEN 06Z AND 14Z. THE ONLY TAF SITE WHERE I AM
CARRYING ANY SUB-VFR CONDITIONS IS KAHN. ISOLATED TO SCATTERED...
MAINLY DIURNALLY DRIVEN...CONVECTION IS EXPECTED THIS AFTERNOON INTO
THE EVENING. HOWEVER THE CHANCES FOR THUNDER AT ANY INDIVIDUAL TAF
SITE IS TOO LOW AT THIS POINT TO INCLUDE IN THE TAFS. WILL CONTINUE
TO WATCH AND AMEND FOR ANY SPECIFIC THREATS TO INDIVIDUAL TAF
AIRFIELDS. BETTER CHANCES FOR THUNDERSTORMS MOVE IN THURSDAY IN
ADVANCE OF AN APPROACHING COLD FRONT...BUT MAINLY AFTER THE END OF
THIS FORECAST PERIOD. WINDS WILL REMAIN WESTERLY MAINLY AT 7KT OR
LESS THROUGH 12Z...INCREASING TO 10-14KT BY 16Z WITH GUSTS 18-24KT.
//ATL CONFIDENCE...12Z UPDATE...
HIGH CONFIDENCE ON CIGS...VSBY AND WINDS. MEDIUM CONFIDENCE ON
CONVECTIVE TRENDS.
20
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 95 70 94 67 / 30 30 50 20
ATLANTA 92 74 92 68 / 30 30 50 30
BLAIRSVILLE 88 67 86 59 / 30 30 50 20
CARTERSVILLE 93 70 93 65 / 30 30 50 20
COLUMBUS 95 75 96 73 / 30 30 20 40
GAINESVILLE 91 72 91 66 / 30 30 50 20
MACON 95 71 96 69 / 30 30 20 40
ROME 94 70 92 66 / 30 30 50 10
PEACHTREE CITY 92 69 93 67 / 30 30 50 30
VIDALIA 96 75 97 73 / 30 30 20 40
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...20
LONG TERM....TDP
AVIATION...20
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
522 PM CDT WED JUN 12 2013
.MESOSCALE DISCUSSION...
510 PM CDT
AS STORMS MOVE INTO NORTHEAST ILLINOIS AND THE FAR WESTERN
SUBURBS OF METRO CHICAGO A LAKE BREEZE BOUNDARY...AND POSSIBLY
ALSO THE STATIONARY FRONT...APPEARS TO EXTEND EAST FROM THE
PRIMARY CLUSTER OF STORMS THROUGH NORTHWEST WILL COUNTY INTO
CENTRAL LAKE COUNTY INDIANA. THIS APPEARS TO BE THE BOUNDARY WHERE
ROTATION HAS BEEN FOCUSING PERIODICALLY IN SOUTHERN DE KALB
COUNTY. CAPE VALUES FALL SOMEWHAT ALONG THE LAKEFRONT...BUT THERE
APPEARS TO BE PLENTY OF SUPPORT FOR SUSTAINING THE EXISTING
ACTIVITY INTO AND SOUTH OF THE CHICAGO METRO AREA...AND EVEN INTO
DOWNTOWN ITSELF. TORNADO SPINUPS ARE VERY POSSIBLE WITH THIS
CLUSTER OF STORMS...ESPECIALLY ALONG THE BOUNDARY IN NORTHERN
KENDALL INTO NORTHWEST WILL COUNTY...AND DAMAGING WINDS AND HAIL
REMAIN EQUALLY LIKELY.
LENNING
243 PM CDT
COUPLE QUICK THOUGHTS ON SOME EVOLUTIONS IN THE MESOSCALE
ENVIRONMENT IN THE PAST 60 TO 90 MINS. DEEPER MIXING IN THE WARM
SECTOR IS ALLOWING SFC WINDS TO VEER CONSIDERABLY ACROSS THE WARM
SECTOR...WHICH IS SIGNIFICANTLY LOWERING THE LOW LEVEL SHEAR AND
POTENTIAL FOR LONG TRACK OR SIGNIFICANT TORNADOES IN THE WARM
SECTOR. WILL NEED TO MONITOR FOR ANY BACKING OF LOW LEVEL FLOW IN
THE WARM SECTOR THIS EVENING...BUT AT THIS POINT IN OUR CWA THE
MORE SIGNIFICANT TORNADO AND HIGH END WIND DAMAGE THREAT WOULD
LIKELY END UP NEAR THE SFC BOUNDARY STALLED OUT FROM ROUGHLY NEAR
CHICAGO WNW TO DBQ. THIS BOUNDARY MAY YET FLUCTUATE SOME THIS
AFTERNOON...BUT WHERE EVER THIS BOUNDARY ENDS UP IS WHERE THE
HIGHEST END SEVERE THREAT WILL LIKELY EXIST WITH SUPERCELL OR MORE
LIKELY WITH STRONG MV`S ALONG LEADING EDGE OF BOW THIS EVENING.
THE 1800 UTC SOUNDINGS FROM DVN AND ILX STILL SHOW A STRONG CAP
PRESENT...HOWEVER COMPARISON OF BOTH SOUNDINGS SHOW EVIDENCE OF
ASCENT TAKING PLACE AND BEGINNING TO LIFT THROUGH THE CAP. ALSO
SEEING EVIDENCE OF THIS ON VISIBLE SATELLITE IMAGERY WITH
GRADUALLY DEEPENING CU FIELD OVER NW IL. HAVE BEGUN TO SEE
CONVECTIVE INITIATION OVER NE IA ALREADY AND EXPECT MORE EXPLOSIVE
SEVERE THUNDERSTORM DEVELOPMENT TO TAKE PLACE WITHIN THE NEXT HOUR
OR TWO.
IZZI
130 PM CDT
THE MAIN THOUGHTS ON THE THREATS AND TIMING ON THE LIKELY SEVERE
WEATHER OUTBREAK REMAIN SIMILAR.
VISIBLE SATELLITE INDICATES MORE AGITATION IN THE ACCAS IN WEST-
TO-EAST BANDS ACROSS THE AREA WITH LIGHT ECHOES CONTINUING ON THE
RADAR MOSAIC. THESE ARE SIGNS OF THE ELEVATED WARM AIR ADVECTION
AND ACTUALLY ALREADY SOME MAMMATUS HAVE BEEN SEEN. STEEP LAPSE
RATES SEEN ON AMDAR DATA AND THE 18Z DVN RAOB ABOVE THIS LAYER
COULD SUPPORT SCATTERED CONVECTION DEVELOPING ACROSS NORTHERN IL
AND FAR NORTHWEST IN WITHIN THE NEXT TWO TO THREE HOURS.
OF GREATER CONCERN IS CONVECTIVE DEVELOPMENT LIKELY OVER NORTHEAST
IA/SOUTHWEST WI/NORTHWEST IL. THE PRIMARY 1004MB SURFACE LOW
ACROSS CENTRAL IA CONTINUES TO DEVELOP EAST WITH 5 MB/3 HR
PRESSURE FALLS CENTERED OVER THE CWA WHERE THE WARM FRONTAL
BOUNDARY HAS POSITIONED ITSELF. THIS BOUNDARY HAS UNDULATED
SOME...BUT APPEARS TO BE NORTH OF I-88 ESE INTO THE CHICAGO METRO
AREA...AND WILL POTENTIALLY BECOME MORE DEFINED WITH CLEARING
OCCURRING ACROSS THE SOUTHERN FORECAST AREA. PRONOUNCED DRYING ON
WATER VAPOR AHEAD OF THE MAIN SHORT WAVE IN SOUTHERN MN AND A MID-
LEVEL WIND MAX WILL CONTINUE TO MOVE EAST AND OVERRIDE THE WARM
FRONTAL REGION ACROSS EASTERN IA SHORTLY. THE DEVELOPMENT OF
CONVECTION SEEN ON HIGH RESOLUTION GUIDANCE ALONG AND NORTH OF THE
WARM FRONT IN THIS AREA IS SUPPORTED BY OBSERVATIONAL
TRENDS...WITH THE DVN RAOB AND RAP ANALYSIS HAVING INDICATED THE
CAP TO BE ERODED.
THIS LIKELY DISCRETE DEVELOPMENT AT FIRST WILL AGAIN EVOLVE EAST
ACROSS NORTH CENTRAL IL AFTER MAINLY 4 PM. THE INSTABILITY AND
SHEAR SPECTRUM OF THE CURRENT ATMOSPHERE ARE NO PROBLEMS FOR
SEVERE STORMS...WITH HIGH CAPE GREATER THAN 2500 J/KG AND
EFFECTIVE DEEP LAYER SHEAR IN EXCESS OF 45 KTS. SUPERCELLS WILL
CERTAINLY BE SUPPORTED. SOME DEVELOPMENT EAST OF THE INITIAL
CELLS...POSSIBLY SURFACE BASED...MAY OCCUR TOO DEPENDING ON IF THE
CIN CAN ERODE AND THE CONVERGENCE ALONG THE SURFACE BOUNDARY IS
ENHANCED. THIS LENDS TO UNCERTAINTY ON WHEN THE FIRST ROBUST
ACTIVITY COULD REACH CHICAGO. BUT THE PRIMARY THREAT TIMES STILL
LOOK TO BE 4-7 PM IN AND AROUND ROCKFORD AND 6-11 PM IN CHICAGO.
OBSERVATIONAL TRENDS CONTINUE TO POINT TOWARDS THE POTENTIAL FOR A
ROBUST MCS...WITH WINDS POTENTIALLY 80 TO 100 MPH WINDS...DEVELOPING
ACROSS THE AREA THIS EVE. ALL INGREDIENTS ARE FAVORABLE FOR
THIS...INCLUDING A STRONG MID-LEVEL JET...SUFFICIENT 0-3 KM SHEAR
FOR COLD POOL ORGANIZATION...A LARGE AREA OF HIGH DOWNDRAFT
CAPE...AND A VEERING STRONG LOW-LEVEL JET INTO A EXISTING
BAROCLINIC GRADIENT. MANY OF THE CONVECTIVE ALLOWING GUIDANCE
INDICATE NOT ONLY MCV TYPE STRUCTURE ACROSS FAR NORTHERN IL RACING
INTO CHICAGO AND NORTHWEST IN THIS EVE...BUT ALSO AGREE ON HIGH
SURFACE-BASED WINDS. RAP AND NAM FORECASTS INTO TONIGHT FOR THE
ENVIRONMENT WOULD SUPPORT THIS AS WOULD THE CONCEPTUAL MODEL OF A
QUICKLY EASTWARD DEVELOPING SURFACE LOW. SOMETHING TO KEEP IN MIND
WITH THE POSSIBLE PATH OF THIS ACROSS FAR SOUTHERN LAKE MI IS THAT
A SEICHE WOULD BE FAVORED IF THAT WERE TO OCCUR. THE 12Z LOCAL ARW
ACTUALLY APPEARS TO HAVE THAT FORECAST IN THE PRESSURE FIELDS.
WILL MENTION THIS AND THE HIGHER ENDS WINDS OVER LAND IN THE HWO.+
&&
.DISCUSSION...
310 PM CDT
FOR WEDNESDAY NIGHT THROUGH TUESDAY...
FOR THE OVERNIGHT HOURS...THE CONCERNS WILL STILL FOCUS ON THE
POTENTIAL FOR SEVERE WEATHER AS WELL AS THE CHANCES FOR FLOODING AND
FLASH FLOODING. FOR DETAILS ON THE FLOODING POTENTIAL...SEE THE
HYDROLOGY DISCUSSION BELOW. THAT SAID...THE ENVIRONMENT WILL BE
PRIMED FOR ANY THUNDERSTORMS TO BE EFFICIENT RAIN PRODUCERS AS THEY
WILL BE IN A VERY MOIST ENVIRONMENT WITH SFC DEWPOINTS IN THE LOW
70S AND PWATS BETWEEN 1.75 AND 2.00 INCHES. FROM A CLIMATOLOGICAL
PERSPECTIVE...THIS PUTS THE REGION IN THE MAXIMUM POTENTIAL FOR THE
MIDDLE OF JUNE. WIDESPREAD AMOUNTS OF 2 TO 3 INCHES ARE
LIKELY...GENERALLY NORTH OF I-80...WITH LOCALIZED AMOUNTS OF UP TO 5
INCHES POSSIBLE IN AREAS WHERE REPEATED TRAINING OF HEAVY
THUNDERSTORMS MAY OCCUR. AT THIS POINT...EXPECT ACTIVE
THUNDERSTORMS OVER AT LEAST PORTIONS OF THE AREA THROUGH MUCH OF THE
NIGHT,,,WITH THUNDERSTORM POTENTIAL ENDING FROM WEST TO EAST DURG
THE EARLY MORNING HOURS.
AS THE SFC LOW ASSOCIATED WITH THE SEVERE WEATHER MOVES OFF TO THE
EAST TOMORROW...HIGH PRESSURE RIDGING...BOTH AT THE SFC AND
ALOFT...WILL BUILD ACROSS THE MIDDLE/UPPER MISSISSIPPI VALLEY AND
MIDWEST REGIONS. CONDITIONS WILL QUICKLY DRY OUT...WITH MOSTLY
CLEAR AND DRY CONDITIONS EXPECTED FOR THURSDAY AND FRIDAY.
TEMPERATURES WILL GENERALLY BE NEAR CLIMATOLOGICAL NORMALS WITH
HIGHS INN THE MIDDLE TO UPPER 70S. THE EXCEPTION WILL BE THE
IMMEDIATE LAKE FRONT WHERE A WEAK PRESSURE GRADIENT AND LIGHT WINDS
WILL ALLOW FOR DAILY LAKE BREEZE DEVELOPMENT. SO...EXPECT THAT THE
LAKE FRONT LOCATIONS SHOULD BE SIGNIFICANTLY COOLER THAT THE INLAND
AREAS WITH HIGHS ONLY IN THE LOWER TO MIDDLE 60S. SFC DEWPOINTS
WILL DROP OFF SIGNIFICANTLY AS WELL...DROPPING INTO THE UPPER 40S TO
LOWER 50S.
FOR THE WEEKEND...A SERIES OF SHORT WAVES WILL BEGIN TO OVERTOP THE
UPPER RIDGE AXIS...AND CROSS THE AREA THROUGH THE DEVELOPING
NORTHWEST FLOW ALOFT. THE FIRST OF THESE SHORT WAVES WILL APPROACH
THE REGION BY SATURDAY MORNING...BRINGING ANOTHER CHANCE FOR SHOWERS
AND THUNDERSTORMS. THE LATEST SPC DAY 3 CONVECTIVE OUTLOOK...12Z
FRIDAY THROUGH 12Z SATURDAY... INDICATES A SLIGHT RISK OF SEVERE
WEATHER OVER THE UPPER MISSOURI VALLEY ASSOCIATED WITH THIS SYSTEM.
THE LATEST DAY 4-8 CONVECTIVE OUTLOOK DOES NOT INDICATE SEVERE
POTENTIAL AT THIS POINT...BUT THE GUIDANCE DOES INDICATE THAT IT IS
A RATHER VIGOROUS WAVE...SO STRONG STORMS ARE A POSSIBILITY. THE
ONE LIMITING FACTOR COULD BE THE LOW LEVEL MOISTURE AVAILABILITY.
THE EXPECTED SFC DEW POINT TRENDS POINT TO A SLOW RETURN OF HIGHER
DEWPOINT AIR...WITH SFC DEWPOINTS ONLY IN THE LOWER TO MIDDLE 50S
FOR EARLY SATURDAY MORNING. DEWPOINTS SHOULD RETURN TO THE MIDDLE
TO UPPER 60S BY SATURDAY EVENING...BUT THE SHORTWAVE SHOULD HAVE
MOVED WELL TO THE EAST AND SHORT WAVE RIDGING WILL BUILD OVER THE
AREA. THIS COULD BRING A SHORT WEAKENING TREND IN THE THUNDERSTORM
POTENTIAL...BUT ANOTHER STRONG SHORT WAVE HOT ON IT`S HEALS WILL
RENEW THE THUNDERSTORM POTENTIAL FOR SATURDAY NIGHT AND LINGERING
INTO SUNDAY. WEAK HIGH PRESSURE AT THE SFC WILL HELP LOWER THE PCPN
POTENTIAL...BUT SOME ISOLATED ACTIVITY CANNOT BE RULES OUT THROUGH
SUNDAY AS TEMPERATURES RISE INTO THE LOWER 80S WITH SFC DEWPOINTS
EXPECTED TO BE IN THE UPPER 60S TO LOWER 70S.
FOR EARLY NEXT WEEK...THE TREND SHOULD BE FOR DECREASING CHANCES FOR
PCPN AND LOWERING TEMPERATURES. MONDAY IS EXPECTED TO REMAIN WARM
AND HUMID WITH HIGHS IN THE LOWER 80S AND DEWPOINTS IN THE MIDDLE TO
UPPER 60S. BY TUESDAY...COOLER/DRIER AIR SHOULD FILTER OVER THE
REGION AS HIGH PRESSURE SPREADS OUT OF THE NORTHERN PLAINS AND INTO
THE MIDWEST AND GREAT LAKES REGIONS.
KREIN
&&
.HYDROLOGY...
315 PM
HAVE CONTINUED A FLASH FLOOD WATCH FOR AREAS GENERALLY NORTH OF A
SUBLETTE ILLINOIS TO DUNNS BRIDGE INDIANA LINE...EXPANDING THE
WATCH AREA TO INCLUDE LEE COUNTY. THERE IS STILL THE POTENTIAL
FOR WIDESPREAD HEAVY RAINFALL OF 2 TO 3 INCHES ACROSS THIS
AREA...WITH LOCALLY UP TO 5 INCHES. THE AREA WILL BE UNDER PWATS
OF 1.75 TO 2 INCHES...WHICH PUTS THE AREA WITHING THE 100TH
PERCENTILE FOR PWATS FOR THE MIDDLE OF JUNE...WHICH ESSENTIALLY
SAYS THAT THE DEEP LAYER MOISTURE DOES NOT GET MUCH HIGHER THAN
THIS. THIS WOULD ALSO INDICATE THAT THE STORMS WILL BE VERY
EFFICIENT RAINFALL PRODUCERS WITH VERY HIGH RAINFALL RATES. WITH
THE AXIS OF HEAVIEST RAIN EXPECTED TO BE OVER LOCATIONS INCLUDING
THE HIGHLY URBANIZED ROCKFORD AND CHICAGO METRO AREAS...URBAN
FLOODING IN LOW LYING AREAS AND VIADUCTS LIKELY. THERE WILL ALSO
LIKELY BE FLOODING OF SMALL STREAMS AND SOME AREA RIVERS THAT HAVE
A REDUCED CAPACITY DUE TO PREVIOUS RAINFALL.
KREIN
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 22Z...
* STRONG/SEVERE THUNDERSTORM POTENTIAL LATE THIS AFTERNOON INTO
THIS EVENING THAT WILL HAVE SIGNIFICANT IMPACTS ON THE
TERMINALS.
* POTENTIAL FOR VERY HEAVY RAIN THIS EVENING...WITH IFR/LIFR VIS
AND IFR CIGS POSSIBLE FOR A PERIOD.
* EAST NORTHEAST WINDS...THEN INCREASING LATER THIS EVENING.
RODRIGUEZ
//DISCUSSION...UPDATED 18Z...
CONTINUE TO MONITOR THE POTENTIAL FOR SIGNIFICANT WEATHER TO AFFECT
THE TERMINALS LATER THIS AFTERNOON THROUGH THIS EVENING. ALTHOUGH
AT THIS TIME...RATHER QUIET ACROSS THE TERMINALS WITH VFR
CONDITIONS IN PLACE. WITH THE TRACK OF THE LOW THIS
MORNING...WINDS HAVE ACTUALLY BEEN ORIENTED MORE OUT OF A
SOUTHERLY DIRECTION TODAY. THIS WILL CONTINUE TO OCCUR WITH SOME
SPORADIC GUSTS BUT WITH A SHIFT BACK TO THE EAST NORTHEAST BY MID
AFTERNOON...WITH WINDS REMAINING MORE NORTHERLY THROUGH THE END OF
THE FORECAST PERIOD. DO EXPECT AN INCREASE IN ACTIVITY BY MID
AFTERNOON WITH SCATTERED SHOWERS/THUNDERSTORMS EXPECTED TO DEVELOP
ACROSS THE TERMINALS. THIS INITIAL ONSET IS EXPECTED TO ONLY HAVE
LIMITED IMPACTS ON THE TERMINALS BUT WITH THIS TO QUICKLY CHANGE
AS WE GO INTO THE LATE AFTERNOON. THUNDERSTORM DEVELOPMENT WILL
INCREASE WITH COVERAGE/INTENSITY OF THESE STORMS ALSO INCREASING
AS THEY SHIFT EAST ACROSS THE TERMINALS. NOT ONLY WILL LOWER
VIS/CEILINGS IN HEAVY RAIN WILL BE POSSIBLE...BUT STRONG/SHIFTING
WINDS ARE DEFINITELY POSSIBLE WITH THE STRONGEST THUNDERSTORMS
LATER THIS AFTERNOON. THIS WILL HAVE TO BE ADDRESSED WITH LATER
AMENDMENTS ONCE THUNDERSTORM INITIATION OCCURS AND THE FULL
THREAT OF CHANGING WEATHER FOR THE TERMINALS IS KNOWN.
SHOWERS/ISOLATED THUNDER SHOULD DIMINISH LATE THIS EVENING THROUGH
OVERNIGHT...WITH DRIER CONDITIONS EXPECTED EARLY THURSDAY MORNING
AS WELL AS CEILINGS IMPROVING.
RODRIGUEZ
//ORD AND MDW CONFIDENCE...UPDATED 22Z...
* HIGH CONFIDENCE WITH THUNDERSTORM TRENDS THIS AFTERNOON...LOW
MEDIUM CONFIDENCE THROUGH TONIGHT.
* MEDIUM TO HIGH CONFIDENCE IN A PERIOD OF VERY HEAVY RAINFALL
WITH LOWER VIS AND CIGS THIS EVENING.
* MEDIUM CONFIDENCE IN WIND SPEED AND DIRECTION.
RODRIGUEZ
//OUTLOOK FOR ORD/MDW FOR 00Z FRIDAY-12Z WEDNESDAY...UPDATED 12Z...
THURSDAY NIGHT AND FRIDAY...VFR. WX NIL.
SAT THRU MON...VFR. CHC TSRA WITH LOCAL MVFR/IFR.
TUESDAY...VFR.
KJB
&&
.MARINE...
229 AM CDT
THE MAIN FORECAST CONCERNS ON THE LAKE IS THE THREAT FOR SEVERE
THUNDERSTORMS THIS AFTERNOON AND EVENING...ESPECIALLY ACROSS
SOUTHERN LAKE MICHIGAN...AND ALSO A PERIOD OF STRONG NORTHERLY WINDS
LATE TONIGHT AND ON THURSDAY.
DENSE FOG REMAINS ACROSS THE LAKE...ESPECIALLY ACROSS THE NORTHERN
HALF OF THE LAKE....AND I REALLY DONT SEE ANY IMPROVEMENT IN THESE
CONDITIONS UNTIL EITHER LATE THIS AFTERNOON OR THIS EVENING...WHEN
THE WINDS START TO BECOME NORTHERLY. THEREFORE...I HAVE EXTENDED THE
ADVISORY FOR THE OPEN WATERS THROUGH THIS AFTERNOON.
SEVERE THUNDERSTORMS LOOK TO BE A GOOD BET THIS AFTERNOON AND
EVENING...ESPECIALLY ACROSS SOUTHERN LAKE MICHGAN. THESE STORMS WILL
BE CAPABLE OF PRODUCING VERY LARGE HAIL AND STRONG DAMAGING WINDS
IN EXCESS OF 50 KT. THE THREAT OF SEVERE STORMS IS QUITE HIGH...SO
KEEP UP TO DATE ON THE LATEST WEATHER INFORMATION.
A SURFACE LOW IS EXPECTED TO PASS SOUTH OF THE LAKE TONIGHT. THIS
WILL SET UP SOME STRONG NORTHERLY WINDS UP TO 30 KT LATE TONIGHT AND
ON THURSDAY. THIS WILL LIKELY RESULT IN SMALL CRAFT ADVISORY
CONDITIONS FOR THE ILLINOIS AND INDIANA NEAR SHORE WATERS DURING THIS
TIME. CONDITIONS SHOULD BEGIN TO IMPROVE ON FRIDAY AS THE WINDS
ABATE AS A SURFACE RIDGE OF HIGH PRESSURE BUILDS ACROSS THE
LAKE.
KJB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...FLASH FLOOD WATCH...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-ILZ010-
ILZ011-ILZ012-ILZ013-ILZ014-ILZ020-ILZ022 UNTIL 4 AM
THURSDAY.
IN...FLASH FLOOD WATCH...INZ001-INZ002 UNTIL 4 AM THURSDAY.
LM...SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742...1 AM THURSDAY TO 4
PM THURSDAY.
SMALL CRAFT ADVISORY...LMZ743-LMZ744-LMZ745...4 AM THURSDAY TO
11 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
513 PM CDT WED JUN 12 2013
.MESOSCALE DISCUSSION...
510 PM CDT
AS STORMS MOVE INTO NORTHEAST ILLINOIS AND THE FAR WESTERN
SUBURBS OF METRO CHICAGO A LAKE BREEZE BOUNDARY...AND POSSIBLY
ALSO THE STATIONARY FRONT...APPEARS TO EXTEND EAST FROM THE
PRIMARY CLUSTER OF STORMS THROUGH NORTHWEST WILL COUNTY INTO
CENTRAL LAKE COUNTY INDIANA. THIS APPEARS TO BE THE BOUNDARY WHERE
ROTATION HAS BEEN FOCUSING PERIODICALLY IN SOUTHERN DE KALB
COUNTY. CAPE VALUES FALL SOMEWHAT ALONG THE LAKEFRONT...BUT THERE
APPEARS TO BE PLENTY OF SUPPORT FOR SUSTAINING THE EXISTING
ACTIVITY INTO AND SOUTH OF THE CHICAGO METRO AREA...AND EVEN INTO
DOWNTOWN ITSELF. TORNADO SPINUPS ARE VERY POSSIBLE WITH THIS
CLUSTER OF STORMS...ESPECIALLY ALONG THE BOUNDARY IN NORTHERN
KENDALL INTO NORTHWEST WILL COUNTY...AND DAMAGING WINDS AND HAIL
REMAIN EQUALLY LIKELY.
LENNING
243 PM CDT
COUPLE QUICK THOUGHTS ON SOME EVOLUTIONS IN THE MESOSCALE
ENVIRONMENT IN THE PAST 60 TO 90 MINS. DEEPER MIXING IN THE WARM
SECTOR IS ALLOWING SFC WINDS TO VEER CONSIDERABLY ACROSS THE WARM
SECTOR...WHICH IS SIGNIFICANTLY LOWERING THE LOW LEVEL SHEAR AND
POTENTIAL FOR LONG TRACK OR SIGNIFICANT TORNADOES IN THE WARM
SECTOR. WILL NEED TO MONITOR FOR ANY BACKING OF LOW LEVEL FLOW IN
THE WARM SECTOR THIS EVENING...BUT AT THIS POINT IN OUR CWA THE
MORE SIGNIFICANT TORNADO AND HIGH END WIND DAMAGE THREAT WOULD
LIKELY END UP NEAR THE SFC BOUNDARY STALLED OUT FROM ROUGHLY NEAR
CHICAGO WNW TO DBQ. THIS BOUNDARY MAY YET FLUCTUATE SOME THIS
AFTERNOON...BUT WHERE EVER THIS BOUNDARY ENDS UP IS WHERE THE
HIGHEST END SEVERE THREAT WILL LIKELY EXIST WITH SUPERCELL OR MORE
LIKELY WITH STRONG MV`S ALONG LEADING EDGE OF BOW THIS EVENING.
THE 1800 UTC SOUNDINGS FROM DVN AND ILX STILL SHOW A STRONG CAP
PRESENT...HOWEVER COMPARISON OF BOTH SOUNDINGS SHOW EVIDENCE OF
ASCENT TAKING PLACE AND BEGINNING TO LIFT THROUGH THE CAP. ALSO
SEEING EVIDENCE OF THIS ON VISIBLE SATELLITE IMAGERY WITH
GRADUALLY DEEPENING CU FIELD OVER NW IL. HAVE BEGUN TO SEE
CONVECTIVE INITIATION OVER NE IA ALREADY AND EXPECT MORE EXPLOSIVE
SEVERE THUNDERSTORM DEVELOPMENT TO TAKE PLACE WITHIN THE NEXT HOUR
OR TWO.
IZZI
130 PM CDT
THE MAIN THOUGHTS ON THE THREATS AND TIMING ON THE LIKELY SEVERE
WEATHER OUTBREAK REMAIN SIMILAR.
VISIBLE SATELLITE INDICATES MORE AGITATION IN THE ACCAS IN WEST-
TO-EAST BANDS ACROSS THE AREA WITH LIGHT ECHOES CONTINUING ON THE
RADAR MOSAIC. THESE ARE SIGNS OF THE ELEVATED WARM AIR ADVECTION
AND ACTUALLY ALREADY SOME MAMMATUS HAVE BEEN SEEN. STEEP LAPSE
RATES SEEN ON AMDAR DATA AND THE 18Z DVN RAOB ABOVE THIS LAYER
COULD SUPPORT SCATTERED CONVECTION DEVELOPING ACROSS NORTHERN IL
AND FAR NORTHWEST IN WITHIN THE NEXT TWO TO THREE HOURS.
OF GREATER CONCERN IS CONVECTIVE DEVELOPMENT LIKELY OVER NORTHEAST
IA/SOUTHWEST WI/NORTHWEST IL. THE PRIMARY 1004MB SURFACE LOW
ACROSS CENTRAL IA CONTINUES TO DEVELOP EAST WITH 5 MB/3 HR
PRESSURE FALLS CENTERED OVER THE CWA WHERE THE WARM FRONTAL
BOUNDARY HAS POSITIONED ITSELF. THIS BOUNDARY HAS UNDULATED
SOME...BUT APPEARS TO BE NORTH OF I-88 ESE INTO THE CHICAGO METRO
AREA...AND WILL POTENTIALLY BECOME MORE DEFINED WITH CLEARING
OCCURRING ACROSS THE SOUTHERN FORECAST AREA. PRONOUNCED DRYING ON
WATER VAPOR AHEAD OF THE MAIN SHORT WAVE IN SOUTHERN MN AND A MID-
LEVEL WIND MAX WILL CONTINUE TO MOVE EAST AND OVERRIDE THE WARM
FRONTAL REGION ACROSS EASTERN IA SHORTLY. THE DEVELOPMENT OF
CONVECTION SEEN ON HIGH RESOLUTION GUIDANCE ALONG AND NORTH OF THE
WARM FRONT IN THIS AREA IS SUPPORTED BY OBSERVATIONAL
TRENDS...WITH THE DVN RAOB AND RAP ANALYSIS HAVING INDICATED THE
CAP TO BE ERODED.
THIS LIKELY DISCRETE DEVELOPMENT AT FIRST WILL AGAIN EVOLVE EAST
ACROSS NORTH CENTRAL IL AFTER MAINLY 4 PM. THE INSTABILITY AND
SHEAR SPECTRUM OF THE CURRENT ATMOSPHERE ARE NO PROBLEMS FOR
SEVERE STORMS...WITH HIGH CAPE GREATER THAN 2500 J/KG AND
EFFECTIVE DEEP LAYER SHEAR IN EXCESS OF 45 KTS. SUPERCELLS WILL
CERTAINLY BE SUPPORTED. SOME DEVELOPMENT EAST OF THE INITIAL
CELLS...POSSIBLY SURFACE BASED...MAY OCCUR TOO DEPENDING ON IF THE
CIN CAN ERODE AND THE CONVERGENCE ALONG THE SURFACE BOUNDARY IS
ENHANCED. THIS LENDS TO UNCERTAINTY ON WHEN THE FIRST ROBUST
ACTIVITY COULD REACH CHICAGO. BUT THE PRIMARY THREAT TIMES STILL
LOOK TO BE 4-7 PM IN AND AROUND ROCKFORD AND 6-11 PM IN CHICAGO.
OBSERVATIONAL TRENDS CONTINUE TO POINT TOWARDS THE POTENTIAL FOR A
ROBUST MCS...WITH WINDS POTENTIALLY 80 TO 100 MPH WINDS...DEVELOPING
ACROSS THE AREA THIS EVE. ALL INGREDIENTS ARE FAVORABLE FOR
THIS...INCLUDING A STRONG MID-LEVEL JET...SUFFICIENT 0-3 KM SHEAR
FOR COLD POOL ORGANIZATION...A LARGE AREA OF HIGH DOWNDRAFT
CAPE...AND A VEERING STRONG LOW-LEVEL JET INTO A EXISTING
BAROCLINIC GRADIENT. MANY OF THE CONVECTIVE ALLOWING GUIDANCE
INDICATE NOT ONLY MCV TYPE STRUCTURE ACROSS FAR NORTHERN IL RACING
INTO CHICAGO AND NORTHWEST IN THIS EVE...BUT ALSO AGREE ON HIGH
SURFACE-BASED WINDS. RAP AND NAM FORECASTS INTO TONIGHT FOR THE
ENVIRONMENT WOULD SUPPORT THIS AS WOULD THE CONCEPTUAL MODEL OF A
QUICKLY EASTWARD DEVELOPING SURFACE LOW. SOMETHING TO KEEP IN MIND
WITH THE POSSIBLE PATH OF THIS ACROSS FAR SOUTHERN LAKE MI IS THAT
A SEICHE WOULD BE FAVORED IF THAT WERE TO OCCUR. THE 12Z LOCAL ARW
ACTUALLY APPEARS TO HAVE THAT FORECAST IN THE PRESSURE FIELDS.
WILL MENTION THIS AND THE HIGHER ENDS WINDS OVER LAND IN THE HWO.+
&&
.DISCUSSION...
310 PM CDT
FOR WEDNESDAY NIGHT THROUGH TUESDAY...
FOR THE OVERNIGHT HOURS...THE CONCERNS WILL STILL FOCUS ON THE
POTENTIAL FOR SEVERE WEATHER AS WELL AS THE CHANCES FOR FLOODING AND
FLASH FLOODING. FOR DETAILS ON THE FLOODING POTENTIAL...SEE THE
HYDROLOGY DISCUSSION BELOW. THAT SAID...THE ENVIRONMENT WILL BE
PRIMED FOR ANY THUNDERSTORMS TO BE EFFICIENT RAIN PRODUCERS AS THEY
WILL BE IN A VERY MOIST ENVIRONMENT WITH SFC DEWPOINTS IN THE LOW
70S AND PWATS BETWEEN 1.75 AND 2.00 INCHES. FROM A CLIMATOLOGICAL
PERSPECTIVE...THIS PUTS THE REGION IN THE MAXIMUM POTENTIAL FOR THE
MIDDLE OF JUNE. WIDESPREAD AMOUNTS OF 2 TO 3 INCHES ARE
LIKELY...GENERALLY NORTH OF I-80...WITH LOCALIZED AMOUNTS OF UP TO 5
INCHES POSSIBLE IN AREAS WHERE REPEATED TRAINING OF HEAVY
THUNDERSTORMS MAY OCCUR. AT THIS POINT...EXPECT ACTIVE
THUNDERSTORMS OVER AT LEAST PORTIONS OF THE AREA THROUGH MUCH OF THE
NIGHT,,,WITH THUNDERSTORM POTENTIAL ENDING FROM WEST TO EAST DURG
THE EARLY MORNING HOURS.
AS THE SFC LOW ASSOCIATED WITH THE SEVERE WEATHER MOVES OFF TO THE
EAST TOMORROW...HIGH PRESSURE RIDGING...BOTH AT THE SFC AND
ALOFT...WILL BUILD ACROSS THE MIDDLE/UPPER MISSISSIPPI VALLEY AND
MIDWEST REGIONS. CONDITIONS WILL QUICKLY DRY OUT...WITH MOSTLY
CLEAR AND DRY CONDITIONS EXPECTED FOR THURSDAY AND FRIDAY.
TEMPERATURES WILL GENERALLY BE NEAR CLIMATOLOGICAL NORMALS WITH
HIGHS INN THE MIDDLE TO UPPER 70S. THE EXCEPTION WILL BE THE
IMMEDIATE LAKE FRONT WHERE A WEAK PRESSURE GRADIENT AND LIGHT WINDS
WILL ALLOW FOR DAILY LAKE BREEZE DEVELOPMENT. SO...EXPECT THAT THE
LAKE FRONT LOCATIONS SHOULD BE SIGNIFICANTLY COOLER THAT THE INLAND
AREAS WITH HIGHS ONLY IN THE LOWER TO MIDDLE 60S. SFC DEWPOINTS
WILL DROP OFF SIGNIFICANTLY AS WELL...DROPPING INTO THE UPPER 40S TO
LOWER 50S.
FOR THE WEEKEND...A SERIES OF SHORT WAVES WILL BEGIN TO OVERTOP THE
UPPER RIDGE AXIS...AND CROSS THE AREA THROUGH THE DEVELOPING
NORTHWEST FLOW ALOFT. THE FIRST OF THESE SHORT WAVES WILL APPROACH
THE REGION BY SATURDAY MORNING...BRINGING ANOTHER CHANCE FOR SHOWERS
AND THUNDERSTORMS. THE LATEST SPC DAY 3 CONVECTIVE OUTLOOK...12Z
FRIDAY THROUGH 12Z SATURDAY... INDICATES A SLIGHT RISK OF SEVERE
WEATHER OVER THE UPPER MISSOURI VALLEY ASSOCIATED WITH THIS SYSTEM.
THE LATEST DAY 4-8 CONVECTIVE OUTLOOK DOES NOT INDICATE SEVERE
POTENTIAL AT THIS POINT...BUT THE GUIDANCE DOES INDICATE THAT IT IS
A RATHER VIGOROUS WAVE...SO STRONG STORMS ARE A POSSIBILITY. THE
ONE LIMITING FACTOR COULD BE THE LOW LEVEL MOISTURE AVAILABILITY.
THE EXPECTED SFC DEW POINT TRENDS POINT TO A SLOW RETURN OF HIGHER
DEWPOINT AIR...WITH SFC DEWPOINTS ONLY IN THE LOWER TO MIDDLE 50S
FOR EARLY SATURDAY MORNING. DEWPOINTS SHOULD RETURN TO THE MIDDLE
TO UPPER 60S BY SATURDAY EVENING...BUT THE SHORTWAVE SHOULD HAVE
MOVED WELL TO THE EAST AND SHORT WAVE RIDGING WILL BUILD OVER THE
AREA. THIS COULD BRING A SHORT WEAKENING TREND IN THE THUNDERSTORM
POTENTIAL...BUT ANOTHER STRONG SHORT WAVE HOT ON IT`S HEALS WILL
RENEW THE THUNDERSTORM POTENTIAL FOR SATURDAY NIGHT AND LINGERING
INTO SUNDAY. WEAK HIGH PRESSURE AT THE SFC WILL HELP LOWER THE PCPN
POTENTIAL...BUT SOME ISOLATED ACTIVITY CANNOT BE RULES OUT THROUGH
SUNDAY AS TEMPERATURES RISE INTO THE LOWER 80S WITH SFC DEWPOINTS
EXPECTED TO BE IN THE UPPER 60S TO LOWER 70S.
FOR EARLY NEXT WEEK...THE TREND SHOULD BE FOR DECREASING CHANCES FOR
PCPN AND LOWERING TEMPERATURES. MONDAY IS EXPECTED TO REMAIN WARM
AND HUMID WITH HIGHS IN THE LOWER 80S AND DEWPOINTS IN THE MIDDLE TO
UPPER 60S. BY TUESDAY...COOLER/DRIER AIR SHOULD FILTER OVER THE
REGION AS HIGH PRESSURE SPREADS OUT OF THE NORTHERN PLAINS AND INTO
THE MIDWEST AND GREAT LAKES REGIONS.
KREIN
&&
.HYDROLOGY...
315 PM
HAVE CONTINUED A FLASH FLOOD WATCH FOR AREAS GENERALLY NORTH OF A
SUBLETTE ILLINOIS TO DUNNS BRIDGE INDIANA LINE...EXPANDING THE
WATCH AREA TO INCLUDE LEE COUNTY. THERE IS STILL THE POTENTIAL
FOR WIDESPREAD HEAVY RAINFALL OF 2 TO 3 INCHES ACROSS THIS
AREA...WITH LOCALLY UP TO 5 INCHES. THE AREA WILL BE UNDER PWATS
OF 1.75 TO 2 INCHES...WHICH PUTS THE AREA WITHING THE 100TH
PERCENTILE FOR PWATS FOR THE MIDDLE OF JUNE...WHICH ESSENTIALLY
SAYS THAT THE DEEP LAYER MOISTURE DOES NOT GET MUCH HIGHER THAN
THIS. THIS WOULD ALSO INDICATE THAT THE STORMS WILL BE VERY
EFFICIENT RAINFALL PRODUCERS WITH VERY HIGH RAINFALL RATES. WITH
THE AXIS OF HEAVIEST RAIN EXPECTED TO BE OVER LOCATIONS INCLUDING
THE HIGHLY URBANIZED ROCKFORD AND CHICAGO METRO AREAS...URBAN
FLOODING IN LOW LYING AREAS AND VIADUCTS LIKELY. THERE WILL ALSO
LIKELY BE FLOODING OF SMALL STREAMS AND SOME AREA RIVERS THAT HAVE
A REDUCED CAPACITY DUE TO PREVIOUS RAINFALL.
KREIN
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 20Z...
* STRONG/SEVERE THUNDERSTORM POTENTIAL LATE THIS AFTERNOON INTO
THIS EVENING THAT COULD HAVE SIGNIFICANT IMPACTS ON THE
TERMINALS...SHOWERS/THUNDERSTORMS INCREASING AFTER 21Z.
* POTENTIAL FOR VERY HEAVY RAIN THIS EVENING...WITH IFR/LIFR VIS
AND IFR CIGS POSSIBLE FOR A PERIOD.
* EAST NORTHEAST WINDS...THEN INCREASING LATER THIS EVENING.
RODRIGUEZ
//DISCUSSION...UPDATED 18Z...
CONTINUE TO MONITOR THE POTENTIAL FOR SIGNIFICANT WEATHER TO AFFECT
THE TERMINALS LATER THIS AFTERNOON THROUGH THIS EVENING. ALTHOUGH
AT THIS TIME...RATHER QUIET ACROSS THE TERMINALS WITH VFR
CONDITIONS IN PLACE. WITH THE TRACK OF THE LOW THIS
MORNING...WINDS HAVE ACTUALLY BEEN ORIENTED MORE OUT OF A
SOUTHERLY DIRECTION TODAY. THIS WILL CONTINUE TO OCCUR WITH SOME
SPORADIC GUSTS BUT WITH A SHIFT BACK TO THE EAST NORTHEAST BY MID
AFTERNOON...WITH WINDS REMAINING MORE NORTHERLY THROUGH THE END OF
THE FORECAST PERIOD. DO EXPECT AN INCREASE IN ACTIVITY BY MID
AFTERNOON WITH SCATTERED SHOWERS/THUNDERSTORMS EXPECTED TO DEVELOP
ACROSS THE TERMINALS. THIS INITIAL ONSET IS EXPECTED TO ONLY HAVE
LIMITED IMPACTS ON THE TERMINALS BUT WITH THIS TO QUICKLY CHANGE
AS WE GO INTO THE LATE AFTERNOON. THUNDERSTORM DEVELOPMENT WILL
INCREASE WITH COVERAGE/INTENSITY OF THESE STORMS ALSO INCREASING
AS THEY SHIFT EAST ACROSS THE TERMINALS. NOT ONLY WILL LOWER
VIS/CEILINGS IN HEAVY RAIN WILL BE POSSIBLE...BUT STRONG/SHIFTING
WINDS ARE DEFINITELY POSSIBLE WITH THE STRONGEST THUNDERSTORMS
LATER THIS AFTERNOON. THIS WILL HAVE TO BE ADDRESSED WITH LATER
AMENDMENTS ONCE THUNDERSTORM INITIATION OCCURS AND THE FULL
THREAT OF CHANGING WEATHER FOR THE TERMINALS IS KNOWN.
SHOWERS/ISOLATED THUNDER SHOULD DIMINISH LATE THIS EVENING THROUGH
OVERNIGHT...WITH DRIER CONDITIONS EXPECTED EARLY THURSDAY MORNING
AS WELL AS CEILINGS IMPROVING.
RODRIGUEZ
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
* MEDIUM TO HIGH CONFIDENCE WITH THUNDERSTORM TRENDS THIS
AFTERNOON THROUGH TONIGHT.
* MEDIUM TO HIGH CONFIDENCE IN A PERIOD OF VERY HEAVY RAINFALL
WITH LOWER VIS AND CIGS THIS EVENING.
* MEDIUM CONFIDENCE IN WIND SPEED AND DIRECTION.
RODRIGUEZ
//OUTLOOK FOR ORD/MDW FOR 00Z FRIDAY-12Z WEDNESDAY...UPDATED 12Z...
THURSDAY NIGHT AND FRIDAY...VFR. WX NIL.
SAT THRU MON...VFR. CHC TSRA WITH LOCAL MVFR/IFR.
TUESDAY...VFR.
KJB
&&
.MARINE...
229 AM CDT
THE MAIN FORECAST CONCERNS ON THE LAKE IS THE THREAT FOR SEVERE
THUNDERSTORMS THIS AFTERNOON AND EVENING...ESPECIALLY ACROSS
SOUTHERN LAKE MICHIGAN...AND ALSO A PERIOD OF STRONG NORTHERLY WINDS
LATE TONIGHT AND ON THURSDAY.
DENSE FOG REMAINS ACROSS THE LAKE...ESPECIALLY ACROSS THE NORTHERN
HALF OF THE LAKE....AND I REALLY DONT SEE ANY IMPROVEMENT IN THESE
CONDITIONS UNTIL EITHER LATE THIS AFTERNOON OR THIS EVENING...WHEN
THE WINDS START TO BECOME NORTHERLY. THEREFORE...I HAVE EXTENDED THE
ADVISORY FOR THE OPEN WATERS THROUGH THIS AFTERNOON.
SEVERE THUNDERSTORMS LOOK TO BE A GOOD BET THIS AFTERNOON AND
EVENING...ESPECIALLY ACROSS SOUTHERN LAKE MICHGAN. THESE STORMS WILL
BE CAPABLE OF PRODUCING VERY LARGE HAIL AND STRONG DAMAGING WINDS
IN EXCESS OF 50 KT. THE THREAT OF SEVERE STORMS IS QUITE HIGH...SO
KEEP UP TO DATE ON THE LATEST WEATHER INFORMATION.
A SURFACE LOW IS EXPECTED TO PASS SOUTH OF THE LAKE TONIGHT. THIS
WILL SET UP SOME STRONG NORTHERLY WINDS UP TO 30 KT LATE TONIGHT AND
ON THURSDAY. THIS WILL LIKELY RESULT IN SMALL CRAFT ADVISORY
CONDITIONS FOR THE ILLINOIS AND INDIANA NEAR SHORE WATERS DURING THIS
TIME. CONDITIONS SHOULD BEGIN TO IMPROVE ON FRIDAY AS THE WINDS
ABATE AS A SURFACE RIDGE OF HIGH PRESSURE BUILDS ACROSS THE
LAKE.
KJB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...FLASH FLOOD WATCH...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-ILZ010-
ILZ011-ILZ012-ILZ013-ILZ014-ILZ020-ILZ022 UNTIL 4 AM
THURSDAY.
IN...FLASH FLOOD WATCH...INZ001-INZ002 UNTIL 4 AM THURSDAY.
LM...SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742...1 AM THURSDAY TO 4
PM THURSDAY.
SMALL CRAFT ADVISORY...LMZ743-LMZ744-LMZ745...4 AM THURSDAY TO
11 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
316 PM CDT WED JUN 12 2013
.MESOSCALE DISCUSSION...
243 PM CDT
COUPLE QUICK THOUGHTS ON SOME EVOLUTIONS IN THE MESOSCALE
ENVIRONMENT IN THE PAST 60 TO 90 MINS. DEEPER MIXING IN THE WARM
SECTOR IS ALLOWING SFC WINDS TO VEER CONSIDERABLY ACROSS THE WARM
SECTOR...WHICH IS SIGNIFICANTLY LOWERING THE LOW LEVEL SHEAR AND
POTENTIAL FOR LONG TRACK OR SIGNIFICANT TORNADOES IN THE WARM
SECTOR. WILL NEED TO MONITOR FOR ANY BACKING OF LOW LEVEL FLOW IN
THE WARM SECTOR THIS EVENING...BUT AT THIS POINT IN OUR CWA THE
MORE SIGNIFICANT TORNADO AND HIGH END WIND DAMAGE THREAT WOULD
LIKELY END UP NEAR THE SFC BOUNDARY STALLED OUT FROM ROUGHLY NEAR
CHICAGO WNW TO DBQ. THIS BOUNDARY MAY YET FLUCTUATE SOME THIS
AFTERNOON...BUT WHERE EVER THIS BOUNDARY ENDS UP IS WHERE THE
HIGHEST END SEVERE THREAT WILL LIKELY EXIST WITH SUPERCELL OR MORE
LIKELY WITH STRONG MV`S ALONG LEADING EDGE OF BOW THIS EVENING.
THE 1800 UTC SOUNDINGS FROM DVN AND ILX STILL SHOW A STRONG CAP
PRESENT...HOWEVER COMPARISON OF BOTH SOUNDINGS SHOW EVIDENCE OF
ASCENT TAKING PLACE AND BEGINNING TO LIFT THROUGH THE CAP. ALSO
SEEING EVIDENCE OF THIS ON VISIBLE SATELLITE IMAGERY WITH
GRADUALLY DEEPENING CU FIELD OVER NW IL. HAVE BEGUN TO SEE
CONVECTIVE INITIATION OVER NE IA ALREADY AND EXPECT MORE EXPLOSIVE
SEVERE THUNDERSTORM DEVELOPMENT TO TAKE PLACE WITHIN THE NEXT HOUR
OR TWO.
IZZI
130 PM CDT
THE MAIN THOUGHTS ON THE THREATS AND TIMING ON THE LIKELY SEVERE
WEATHER OUTBREAK REMAIN SIMILAR.
VISIBLE SATELLITE INDICATES MORE AGITATION IN THE ACCAS IN WEST-
TO-EAST BANDS ACROSS THE AREA WITH LIGHT ECHOES CONTINUING ON THE
RADAR MOSAIC. THESE ARE SIGNS OF THE ELEVATED WARM AIR ADVECTION
AND ACTUALLY ALREADY SOME MAMMATUS HAVE BEEN SEEN. STEEP LAPSE
RATES SEEN ON AMDAR DATA AND THE 18Z DVN RAOB ABOVE THIS LAYER
COULD SUPPORT SCATTERED CONVECTION DEVELOPING ACROSS NORTHERN IL
AND FAR NORTHWEST IN WITHIN THE NEXT TWO TO THREE HOURS.
OF GREATER CONCERN IS CONVECTIVE DEVELOPMENT LIKELY OVER NORTHEAST
IA/SOUTHWEST WI/NORTHWEST IL. THE PRIMARY 1004MB SURFACE LOW
ACROSS CENTRAL IA CONTINUES TO DEVELOP EAST WITH 5 MB/3 HR
PRESSURE FALLS CENTERED OVER THE CWA WHERE THE WARM FRONTAL
BOUNDARY HAS POSITIONED ITSELF. THIS BOUNDARY HAS UNDULATED
SOME...BUT APPEARS TO BE NORTH OF I-88 ESE INTO THE CHICAGO METRO
AREA...AND WILL POTENTIALLY BECOME MORE DEFINED WITH CLEARING
OCCURRING ACROSS THE SOUTHERN FORECAST AREA. PRONOUNCED DRYING ON
WATER VAPOR AHEAD OF THE MAIN SHORT WAVE IN SOUTHERN MN AND A MID-
LEVEL WIND MAX WILL CONTINUE TO MOVE EAST AND OVERRIDE THE WARM
FRONTAL REGION ACROSS EASTERN IA SHORTLY. THE DEVELOPMENT OF
CONVECTION SEEN ON HIGH RESOLUTION GUIDANCE ALONG AND NORTH OF THE
WARM FRONT IN THIS AREA IS SUPPORTED BY OBSERVATIONAL
TRENDS...WITH THE DVN RAOB AND RAP ANALYSIS HAVING INDICATED THE
CAP TO BE ERODED.
THIS LIKELY DISCRETE DEVELOPMENT AT FIRST WILL AGAIN EVOLVE EAST
ACROSS NORTH CENTRAL IL AFTER MAINLY 4 PM. THE INSTABILITY AND
SHEAR SPECTRUM OF THE CURRENT ATMOSPHERE ARE NO PROBLEMS FOR
SEVERE STORMS...WITH HIGH CAPE GREATER THAN 2500 J/KG AND
EFFECTIVE DEEP LAYER SHEAR IN EXCESS OF 45 KTS. SUPERCELLS WILL
CERTAINLY BE SUPPORTED. SOME DEVELOPMENT EAST OF THE INITIAL
CELLS...POSSIBLY SURFACE BASED...MAY OCCUR TOO DEPENDING ON IF THE
CIN CAN ERODE AND THE CONVERGENCE ALONG THE SURFACE BOUNDARY IS
ENHANCED. THIS LENDS TO UNCERTAINTY ON WHEN THE FIRST ROBUST
ACTIVITY COULD REACH CHICAGO. BUT THE PRIMARY THREAT TIMES STILL
LOOK TO BE 4-7 PM IN AND AROUND ROCKFORD AND 6-11 PM IN CHICAGO.
OBSERVATIONAL TRENDS CONTINUE TO POINT TOWARDS THE POTENTIAL FOR A
ROBUST MCS...WITH WINDS POTENTIALLY 80 TO 100 MPH WINDS...DEVELOPING
ACROSS THE AREA THIS EVE. ALL INGREDIENTS ARE FAVORABLE FOR
THIS...INCLUDING A STRONG MID-LEVEL JET...SUFFICIENT 0-3 KM SHEAR
FOR COLD POOL ORGANIZATION...A LARGE AREA OF HIGH DOWNDRAFT
CAPE...AND A VEERING STRONG LOW-LEVEL JET INTO A EXISTING
BAROCLINIC GRADIENT. MANY OF THE CONVECTIVE ALLOWING GUIDANCE
INDICATE NOT ONLY MCV TYPE STRUCTURE ACROSS FAR NORTHERN IL RACING
INTO CHICAGO AND NORTHWEST IN THIS EVE...BUT ALSO AGREE ON HIGH
SURFACE-BASED WINDS. RAP AND NAM FORECASTS INTO TONIGHT FOR THE
ENVIRONMENT WOULD SUPPORT THIS AS WOULD THE CONCEPTUAL MODEL OF A
QUICKLY EASTWARD DEVELOPING SURFACE LOW. SOMETHING TO KEEP IN MIND
WITH THE POSSIBLE PATH OF THIS ACROSS FAR SOUTHERN LAKE MI IS THAT
A SEICHE WOULD BE FAVORED IF THAT WERE TO OCCUR. THE 12Z LOCAL ARW
ACTUALLY APPEARS TO HAVE THAT FORECAST IN THE PRESSURE FIELDS.
WILL MENTION THIS AND THE HIGHER ENDS WINDS OVER LAND IN THE HWO.+
&&
.DISCUSSION...
310 PM CDT
FOR WEDNESDAY NIGHT THROUGH TUESDAY...
FOR THE OVERNIGHT HOURS...THE CONCERNS WILL STILL FOCUS ON THE
POTENTIAL FOR SEVERE WEATHER AS WELL AS THE CHANCES FOR FLOODING AND
FLASH FLOODING. FOR DETAILS ON THE FLOODING POTENTIAL...SEE THE
HYDROLOGY DISCUSSION BELOW. THAT SAID...THE ENVIRONMENT WILL BE
PRIMED FOR ANY THUNDERSTORMS TO BE EFFICIENT RAIN PRODUCERS AS THEY
WILL BE IN A VERY MOIST ENVIRONMENT WITH SFC DEWPOINTS IN THE LOW
70S AND PWATS BETWEEN 1.75 AND 2.00 INCHES. FROM A CLIMATOLOGICAL
PERSPECTIVE...THIS PUTS THE REGION IN THE MAXIMUM POTENTIAL FOR THE
MIDDLE OF JUNE. WIDESPREAD AMOUNTS OF 2 TO 3 INCHES ARE
LIKELY...GENERALLY NORTH OF I-80...WITH LOCALIZED AMOUNTS OF UP TO 5
INCHES POSSIBLE IN AREAS WHERE REPEATED TRAINING OF HEAVY
THUNDERSTORMS MAY OCCUR. AT THIS POINT...EXPECT ACTIVE
THUNDERSTORMS OVER AT LEAST PORTIONS OF THE AREA THROUGH MUCH OF THE
NIGHT,,,WITH THUNDERSTORM POTENTIAL ENDING FROM WEST TO EAST DURG
THE EARLY MORNING HOURS.
AS THE SFC LOW ASSOCIATED WITH THE SEVERE WEATHER MOVES OFF TO THE
EAST TOMORROW...HIGH PRESSURE RIDGING...BOTH AT THE SFC AND
ALOFT...WILL BUILD ACROSS THE MIDDLE/UPPER MISSISSIPPI VALLEY AND
MIDWEST REGIONS. CONDITIONS WILL QUICKLY DRY OUT...WITH MOSTLY
CLEAR AND DRY CONDITIONS EXPECTED FOR THURSDAY AND FRIDAY.
TEMPERATURES WILL GENERALLY BE NEAR CLIMATOLOGICAL NORMALS WITH
HIGHS INN THE MIDDLE TO UPPER 70S. THE EXCEPTION WILL BE THE
IMMEDIATE LAKE FRONT WHERE A WEAK PRESSURE GRADIENT AND LIGHT WINDS
WILL ALLOW FOR DAILY LAKE BREEZE DEVELOPMENT. SO...EXPECT THAT THE
LAKE FRONT LOCATIONS SHOULD BE SIGNIFICANTLY COOLER THAT THE INLAND
AREAS WITH HIGHS ONLY IN THE LOWER TO MIDDLE 60S. SFC DEWPOINTS
WILL DROP OFF SIGNIFICANTLY AS WELL...DROPPING INTO THE UPPER 40S TO
LOWER 50S.
FOR THE WEEKEND...A SERIES OF SHORT WAVES WILL BEGIN TO OVERTOP THE
UPPER RIDGE AXIS...AND CROSS THE AREA THROUGH THE DEVELOPING
NORTHWEST FLOW ALOFT. THE FIRST OF THESE SHORT WAVES WILL APPROACH
THE REGION BY SATURDAY MORNING...BRINGING ANOTHER CHANCE FOR SHOWERS
AND THUNDERSTORMS. THE LATEST SPC DAY 3 CONVECTIVE OUTLOOK...12Z
FRIDAY THROUGH 12Z SATURDAY... INDICATES A SLIGHT RISK OF SEVERE
WEATHER OVER THE UPPER MISSOURI VALLEY ASSOCIATED WITH THIS SYSTEM.
THE LATEST DAY 4-8 CONVECTIVE OUTLOOK DOES NOT INDICATE SEVERE
POTENTIAL AT THIS POINT...BUT THE GUIDANCE DOES INDICATE THAT IT IS
A RATHER VIGOROUS WAVE...SO STRONG STORMS ARE A POSSIBILITY. THE
ONE LIMITING FACTOR COULD BE THE LOW LEVEL MOISTURE AVAILABILITY.
THE EXPECTED SFC DEW POINT TRENDS POINT TO A SLOW RETURN OF HIGHER
DEWPOINT AIR...WITH SFC DEWPOINTS ONLY IN THE LOWER TO MIDDLE 50S
FOR EARLY SATURDAY MORNING. DEWPOINTS SHOULD RETURN TO THE MIDDLE
TO UPPER 60S BY SATURDAY EVENING...BUT THE SHORTWAVE SHOULD HAVE
MOVED WELL TO THE EAST AND SHORT WAVE RIDGING WILL BUILD OVER THE
AREA. THIS COULD BRING A SHORT WEAKENING TREND IN THE THUNDERSTORM
POTENTIAL...BUT ANOTHER STRONG SHORT WAVE HOT ON IT`S HEALS WILL
RENEW THE THUNDERSTORM POTENTIAL FOR SATURDAY NIGHT AND LINGERING
INTO SUNDAY. WEAK HIGH PRESSURE AT THE SFC WILL HELP LOWER THE PCPN
POTENTIAL...BUT SOME ISOLATED ACTIVITY CANNOT BE RULES OUT THROUGH
SUNDAY AS TEMPERATURES RISE INTO THE LOWER 80S WITH SFC DEWPOINTS
EXPECTED TO BE IN THE UPPER 60S TO LOWER 70S.
FOR EARLY NEXT WEEK...THE TREND SHOULD BE FOR DECREASING CHANCES FOR
PCPN AND LOWERING TEMPERATURES. MONDAY IS EXPECTED TO REMAIN WARM
AND HUMID WITH HIGHS IN THE LOWER 80S AND DEWPOINTS IN THE MIDDLE TO
UPPER 60S. BY TUESDAY...COOLER/DRIER AIR SHOULD FILTER OVER THE
REGION AS HIGH PRESSURE SPREADS OUT OF THE NORTHERN PLAINS AND INTO
THE MIDWEST AND GREAT LAKES REGIONS.
KREIN
&&
.HYDROLOGY...
315 PM
HAVE CONTINUED A FLASH FLOOD WATCH FOR AREAS GENERALLY NORTH OF A
SUBLETTE ILLINOIS TO DUNNS BRIDGE INDIANA LINE...EXPANDING THE
WATCH AREA TO INCLUDE LEE COUNTY. THERE IS STILL THE POTENTIAL
FOR WIDESPREAD HEAVY RAINFALL OF 2 TO 3 INCHES ACROSS THIS
AREA...WITH LOCALLY UP TO 5 INCHES. THE AREA WILL BE UNDER PWATS
OF 1.75 TO 2 INCHES...WHICH PUTS THE AREA WITHING THE 100TH
PERCENTILE FOR PWATS FOR THE MIDDLE OF JUNE...WHICH ESSENTIALLY
SAYS THAT THE DEEP LAYER MOISTURE DOES NOT GET MUCH HIGHER THAN
THIS. THIS WOULD ALSO INDICATE THAT THE STORMS WILL BE VERY
EFFICIENT RAINFALL PRODUCERS WITH VERY HIGH RAINFALL RATES. WITH
THE AXIS OF HEAVIEST RAIN EXPECTED TO BE OVER LOCATIONS INCLUDING
THE HIGHLY URBANIZED ROCKFORD AND CHICAGO METRO AREAS...URBAN
FLOODING IN LOW LYING AREAS AND VIADUCTS LIKELY. THERE WILL ALSO
LIKELY BE FLOODING OF SMALL STREAMS AND SOME AREA RIVERS THAT HAVE
A REDUCED CAPACITY DUE TO PREVIOUS RAINFALL.
KREIN
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 20Z...
* STRONG/SEVERE THUNDERSTORM POTENTIAL LATE THIS AFTERNOON INTO
THIS EVENING THAT COULD HAVE SIGNIFICANT IMPACTS ON THE
TERMINALS...SHOWERS/THUNDERSTORMS INCREASING AFTER 21Z.
* POTENTIAL FOR VERY HEAVY RAIN THIS EVENING...WITH IFR/LIFR VIS
AND IFR CIGS POSSIBLE FOR A PERIOD.
* EAST NORTHEAST WINDS...THEN INCREASING LATER THIS EVENING.
RODRIGUEZ
//DISCUSSION...UPDATED 18Z...
CONTINUE TO MONITOR THE POTENTIAL FOR SIGNIFICANT WEATHER TO AFFECT
THE TERMINALS LATER THIS AFTERNOON THROUGH THIS EVENING. ALTHOUGH
AT THIS TIME...RATHER QUIET ACROSS THE TERMINALS WITH VFR
CONDITIONS IN PLACE. WITH THE TRACK OF THE LOW THIS
MORNING...WINDS HAVE ACTUALLY BEEN ORIENTED MORE OUT OF A
SOUTHERLY DIRECTION TODAY. THIS WILL CONTINUE TO OCCUR WITH SOME
SPORADIC GUSTS BUT WITH A SHIFT BACK TO THE EAST NORTHEAST BY MID
AFTERNOON...WITH WINDS REMAINING MORE NORTHERLY THROUGH THE END OF
THE FORECAST PERIOD. DO EXPECT AN INCREASE IN ACTIVITY BY MID
AFTERNOON WITH SCATTERED SHOWERS/THUNDERSTORMS EXPECTED TO DEVELOP
ACROSS THE TERMINALS. THIS INITIAL ONSET IS EXPECTED TO ONLY HAVE
LIMITED IMPACTS ON THE TERMINALS BUT WITH THIS TO QUICKLY CHANGE
AS WE GO INTO THE LATE AFTERNOON. THUNDERSTORM DEVELOPMENT WILL
INCREASE WITH COVERAGE/INTENSITY OF THESE STORMS ALSO INCREASING
AS THEY SHIFT EAST ACROSS THE TERMINALS. NOT ONLY WILL LOWER
VIS/CEILINGS IN HEAVY RAIN WILL BE POSSIBLE...BUT STRONG/SHIFTING
WINDS ARE DEFINITELY POSSIBLE WITH THE STRONGEST THUNDERSTORMS
LATER THIS AFTERNOON. THIS WILL HAVE TO BE ADDRESSED WITH LATER
AMENDMENTS ONCE THUNDERSTORM INITIATION OCCURS AND THE FULL
THREAT OF CHANGING WEATHER FOR THE TERMINALS IS KNOWN.
SHOWERS/ISOLATED THUNDER SHOULD DIMINISH LATE THIS EVENING THROUGH
OVERNIGHT...WITH DRIER CONDITIONS EXPECTED EARLY THURSDAY MORNING
AS WELL AS CEILINGS IMPROVING.
RODRIGUEZ
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
* MEDIUM TO HIGH CONFIDENCE WITH THUNDERSTORM TRENDS THIS
AFTERNOON THROUGH TONIGHT.
* MEDIUM TO HIGH CONFIDENCE IN A PERIOD OF VERY HEAVY RAINFALL
WITH LOWER VIS AND CIGS THIS EVENING.
* MEDIUM CONFIDENCE IN WIND SPEED AND DIRECTION.
RODRIGUEZ
//OUTLOOK FOR ORD/MDW FOR 00Z FRIDAY-12Z WEDNESDAY...UPDATED 12Z...
THURSDAY NIGHT AND FRIDAY...VFR. WX NIL.
SAT THRU MON...VFR. CHC TSRA WITH LOCAL MVFR/IFR.
TUESDAY...VFR.
KJB
&&
.MARINE...
229 AM CDT
THE MAIN FORECAST CONCERNS ON THE LAKE IS THE THREAT FOR SEVERE
THUNDERSTORMS THIS AFTERNOON AND EVENING...ESPECIALLY ACROSS
SOUTHERN LAKE MICHIGAN...AND ALSO A PERIOD OF STRONG NORTHERLY WINDS
LATE TONIGHT AND ON THURSDAY.
DENSE FOG REMAINS ACROSS THE LAKE...ESPECIALLY ACROSS THE NORTHERN
HALF OF THE LAKE....AND I REALLY DONT SEE ANY IMPROVEMENT IN THESE
CONDITIONS UNTIL EITHER LATE THIS AFTERNOON OR THIS EVENING...WHEN
THE WINDS START TO BECOME NORTHERLY. THEREFORE...I HAVE EXTENDED THE
ADVISORY FOR THE OPEN WATERS THROUGH THIS AFTERNOON.
SEVERE THUNDERSTORMS LOOK TO BE A GOOD BET THIS AFTERNOON AND
EVENING...ESPECIALLY ACROSS SOUTHERN LAKE MICHGAN. THESE STORMS WILL
BE CAPABLE OF PRODUCING VERY LARGE HAIL AND STRONG DAMAGING WINDS
IN EXCESS OF 50 KT. THE THREAT OF SEVERE STORMS IS QUITE HIGH...SO
KEEP UP TO DATE ON THE LATEST WEATHER INFORMATION.
A SURFACE LOW IS EXPECTED TO PASS SOUTH OF THE LAKE TONIGHT. THIS
WILL SET UP SOME STRONG NORTHERLY WINDS UP TO 30 KT LATE TONIGHT AND
ON THURSDAY. THIS WILL LIKELY RESULT IN SMALL CRAFT ADVISORY
CONDITIONS FOR THE ILLINOIS AND INDIANA NEAR SHORE WATERS DURING THIS
TIME. CONDITIONS SHOULD BEGIN TO IMPROVE ON FRIDAY AS THE WINDS
ABATE AS A SURFACE RIDGE OF HIGH PRESSURE BUILDS ACROSS THE
LAKE.
KJB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...FLASH FLOOD WATCH...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-ILZ010-
ILZ011-ILZ012-ILZ013-ILZ014-ILZ020-ILZ022 UNTIL 4 AM
THURSDAY.
IN...FLASH FLOOD WATCH...INZ001-INZ002 UNTIL 4 AM THURSDAY.
LM...DENSE FOG ADVISORY...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-
LMZ565-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-
LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 4 PM
WEDNESDAY.
SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742...1 AM THURSDAY TO 4
PM THURSDAY.
SMALL CRAFT ADVISORY...LMZ743-LMZ744-LMZ745...4 AM THURSDAY TO
11 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
254 PM CDT WED JUN 12 2013
.MESOSCALE DISCUSSION...
243 PM CDT
COUPLE QUICK THOUGHTS ON SOME EVOLUTIONS IN THE MESOSCALE
ENVIRONMENT IN THE PAST 60 TO 90 MINS. DEEPER MIXING IN THE WARM
SECTOR IS ALLOWING SFC WINDS TO VEER CONSIDERABLY ACROSS THE WARM
SECTOR...WHICH IS SIGNIFICANTLY LOWERING THE LOW LEVEL SHEAR AND
POTENTIAL FOR LONG TRACK OR SIGNIFICANT TORNADOES IN THE WARM
SECTOR. WILL NEED TO MONITOR FOR ANY BACKING OF LOW LEVEL FLOW IN
THE WARM SECTOR THIS EVENING...BUT AT THIS POINT IN OUR CWA THE
MORE SIGNIFICANT TORNADO AND HIGH END WIND DAMAGE THREAT WOULD
LIKELY END UP NEAR THE SFC BOUNDARY STALLED OUT FROM ROUGHLY NEAR
CHICAGO WNW TO DBQ. THIS BOUNDARY MAY YET FLUCTUATE SOME THIS
AFTERNOON...BUT WHERE EVER THIS BOUNDARY ENDS UP IS WHERE THE
HIGHEST END SEVERE THREAT WILL LIKELY EXIST WITH SUPERCELL OR MORE
LIKELY WITH STRONG MV`S ALONG LEADING EDGE OF BOW THIS EVENING.
THE 1800 UTC SOUNDINGS FROM DVN AND ILX STILL SHOW A STRONG CAP
PRESENT...HOWEVER COMPARISON OF BOTH SOUNDINGS SHOW EVIDENCE OF
ASCENT TAKING PLACE AND BEGINNING TO LIFT THROUGH THE CAP. ALSO
SEEING EVIDENCE OF THIS ON VISIBLE SATELLITE IMAGERY WITH
GRADUALLY DEEPENING CU FIELD OVER NW IL. HAVE BEGUN TO SEE
CONVECTIVE INITIATION OVER NE IA ALREADY AND EXPECT MORE EXPLOSIVE
SEVERE THUNDERSTORM DEVELOPMENT TO TAKE PLACE WITHIN THE NEXT HOUR
OR TWO.
IZZI
130 PM CDT
THE MAIN THOUGHTS ON THE THREATS AND TIMING ON THE LIKELY SEVERE
WEATHER OUTBREAK REMAIN SIMILAR.
VISIBLE SATELLITE INDICATES MORE AGITATION IN THE ACCAS IN WEST-
TO-EAST BANDS ACROSS THE AREA WITH LIGHT ECHOES CONTINUING ON THE
RADAR MOSAIC. THESE ARE SIGNS OF THE ELEVATED WARM AIR ADVECTION
AND ACTUALLY ALREADY SOME MAMMATUS HAVE BEEN SEEN. STEEP LAPSE
RATES SEEN ON AMDAR DATA AND THE 18Z DVN RAOB ABOVE THIS LAYER
COULD SUPPORT SCATTERED CONVECTION DEVELOPING ACROSS NORTHERN IL
AND FAR NORTHWEST IN WITHIN THE NEXT TWO TO THREE HOURS.
OF GREATER CONCERN IS CONVECTIVE DEVELOPMENT LIKELY OVER NORTHEAST
IA/SOUTHWEST WI/NORTHWEST IL. THE PRIMARY 1004MB SURFACE LOW
ACROSS CENTRAL IA CONTINUES TO DEVELOP EAST WITH 5 MB/3 HR
PRESSURE FALLS CENTERED OVER THE CWA WHERE THE WARM FRONTAL
BOUNDARY HAS POSITIONED ITSELF. THIS BOUNDARY HAS UNDULATED
SOME...BUT APPEARS TO BE NORTH OF I-88 ESE INTO THE CHICAGO METRO
AREA...AND WILL POTENTIALLY BECOME MORE DEFINED WITH CLEARING
OCCURING ACROSS THE SOUTHERN FORECAST AREA. PRONOUNCED DRYING ON
WATER VAPOR AHEAD OF THE MAIN SHORT WAVE IN SOUTHERN MN AND A MID-
LEVEL WIND MAX WILL CONTINUE TO MOVE EAST AND OVERRIDE THE WARM
FRONTAL REGION ACROSS EASTERN IA SHORTLY. THE DEVELOPMENT OF
CONVECTION SEEN ON HIGH RESOLUTION GUIDANCE ALONG AND NORTH OF THE
WARM FRONT IN THIS AREA IS SUPPORTED BY OBSERVATIONAL
TRENDS...WITH THE DVN RAOB AND RAP ANALYSIS HAVING INDICATED THE
CAP TO BE ERODED.
THIS LIKELY DISCRETE DEVELOPMENT AT FIRST WILL AGAIN EVOLVE EAST
ACROSS NORTH CENTRAL IL AFTER MAINLY 4 PM. THE INSTABILITY AND
SHEAR SPECTRUM OF THE CURRENT ATMOSPHERE ARE NO PROBLEMS FOR
SEVERE STORMS...WITH HIGH CAPE GREATER THAN 2500 J/KG AND
EFFECTIVE DEEP LAYER SHEAR IN EXCESS OF 45 KTS. SUPERCELLS WILL
CERTAINLY BE SUPPORTED. SOME DEVELOPMENT EAST OF THE INITIAL
CELLS...POSSIBLY SURFACE BASED...MAY OCCUR TOO DEPENDING ON IF THE
CIN CAN ERODE AND THE CONVERGENCE ALONG THE SURFACE BOUNDARY IS
ENHANCED. THIS LENDS TO UNCERTAINTY ON WHEN THE FIRST ROBUST
ACTIVITY COULD REACH CHICAGO. BUT THE PRIMARY THREAT TIMES STILL
LOOK TO BE 4-7 PM IN AND AROUND ROCKFORD AND 6-11 PM IN CHICAGO.
OBSERVATIONAL TRENDS CONTINUE TO POINT TOWARDS THE POTENTIAL FOR A
ROBUST MCS...WITH WINDS POTENTIALLY 80 TO 100 MPH WINDS...DEVELOPING
ACROSS THE AREA THIS EVE. ALL INGREDIENTS ARE FAVORABLE FOR
THIS...INCLUDING A STRONG MID-LEVEL JET...SUFFICIENT 0-3 KM SHEAR
FOR COLD POOL ORGANIZATION...A LARGE AREA OF HIGH DOWNDRAFT
CAPE...AND A VEERING STRONG LOW-LEVEL JET INTO A EXISTING
BAROCLINIC GRADIENT. MANY OF THE CONVECTIVE ALLOWING GUIDANCE
INDICATE NOT ONLY MCV TYPE STRUCTURE ACROSS FAR NORTHERN IL RACING
INTO CHICAGO AND NORTHWEST IN THIS EVE...BUT ALSO AGREE ON HIGH
SURFACE-BASED WINDS. RAP AND NAM FORECASTS INTO TONIGHT FOR THE
ENVIRONMENT WOULD SUPPORT THIS AS WOULD THE CONCEPTUAL MODEL OF A
QUICKLY EASTWARD DEVELOPING SURFACE LOW. SOMETHING TO KEEP IN MIND
WITH THE POSSIBLE PATH OF THIS ACROSS FAR SOUTHERN LAKE MI IS THAT
A SEICHE WOULD BE FAVORED IF THAT WERE TO OCCUR. THE 12Z LOCAL ARW
ACTUALLY APPEARS TO HAVE THAT FORECAST IN THE PRESSURE FIELDS.
WILL MENTION THIS AND THE HIGHER ENDS WINDS OVER LAND IN THE HWO.+
&&
.DISCUSSION...
304 AM CDT
...MAJOR SEVERE WEATHER OUTBREAK LIKELY THIS AFTERNOON AND
EVENING...WITH HEAVY RAINFALL ALSO LIKELY...
EVERYTHING LINING UP FOR A SIGNIFICANT SEVERE WEATHER OUTBREAK
TODAY. SPC DAY 1 OUTLOOK HAS ENTIRE FORECAST AREA IN MODERATE RISK
OF SEVERE WITH SIGNIFICANT WIND...HAIL...AND TORNADO THREAT. AT THE
SURFACE...LOW PRESSURE OVER THE PLAINS WITH A WEAK WARM FRONT
EXTENDING EAST INTO NORTHERN IL EARLY THIS MORNING. THE LOW WILL
MOVE EAST ALONG THE IA/MO BOARDER TODAY...AND ACROSS NORTHERN IL
THIS EVENING. VERY MOIST LOW LEVEL AIR WITH SURFACE DEW POINTS IN
THE MID AND UPPER 60S IN PLACE. MAY SEE DEWPOINTS POOL IN THE LOWER
70S SOUTH OF WARM FRONT THIS AFTERNOON. THE BOUNDARY WILL INTENSIFY
AS SOUTHWEST LOW LEVEL FLOW INCREASES SOUTH OF THE FRONT AND SURFACE
WINDS BACK TO SE OR E NORTH OF THE BOUNDARY. THIS WILL PULL MODIFIED
MARINE AIR BACK ACROSS FAR NORTHERN IL. HAVE SOME CONCERNS ABOUT HOW
FAR NORTH THE WARM FRONT WILL TRAVEL. SPC DISCUSSION SUGGESTING THE
BOUNDARY WILL MOVE INTO SOUTHERN WI BUT WITH MODELS TAKING LOW
ACROSS I-80 CORRIDOR AND COOLING INFLUENCE OF LAKE
MICHIGAN...THINKING FRONT WONT GET MUCH FARTHER NORTH THAN A
DIXON-GARY LINE. THIS MAY LIMIT NORTHERN EXTEND OF SIGNIFICANT
SEVERE THREAT. THE BOUNDARY WILL ALSO RESULT IN A CHALLENGING
TEMPERATURE FORECAST...WITH TEMPS REACHING LOWER 90S FAR SOUTHERN
PART OF FORECAST AREA...WHILE AREAS ALONG THE NORTH SHORE WILL
LIKELY BE 20 DEGREES COOLER. IT APPEARS THAT MOST OF THE OVERNIGHT
EARLY MORNING CONVECTION WILL AFFECT WI...BUT KEEPING AN EYE ON
MCS OVER WESTERN IA WHICH COULD MOVE INTO NORTHERN IL THIS
MORNING. EARLIER CONVECTION OVER EASTERN IA WEAKENED AS IT MOVED
EAST AND THINK THIS MCS MAY DO THE SAME. CLOUD DEBRIS SHOULD
REMAIN NORTH ALLOWING AREAS SOUTH OF THE WARM FRONT TO HEAT UP
SIGNIFICANTLY...INTO THE UPPER 80S TO LOWER 90S. THIS COULD RESULT
IN SURFACE BASED CAPE OF 3000+ THIS AFTERNOON. FAIRLY VIGOROUS
SHORT WAVE MOVING INTO WESTERN SD/NE EARLY THIS MORNING WILL BE
MOVING ACROSS NORTHERN IL THIS EVENING. MODEL SOUNDINGS SHOW
FAIRLY STOUT CAP EARLY IN THE DAY ERODES THIS AFTERNOON WITH
APPROACHING SHORT WAVE. LOOKING AT 0-6KM BULK SHEAR 50-60 KTS BY
THIS EVENING. WITH INCREASING LOW LEVEL FLOW THIS AFTERNOON AND
BACKING SURFACE WINDS ALONG THE BOUNDARY...SHOULD PRODUCE AN
ENVIRONMENT FAVORABLE FOR DAMAGING WINDS...LARGE HAIL...AND
TORNADOES. SOME OF THE SHORT RANGE HI RES GUIDANCE IS SUGGESTING
DISCRETE STORMS INITIALLY THIS AFTERNOON. EXPECT THE TORNADO
THREAT TO BE MAINLY DURING THE AFTERNOON. STORMS WILL LIKELY
CONGEAL INTO AN MCS AND BECOME MORE OF A HIGH WIND WITH EMBEDDED
QLCS TORNADO THREAT IN THE EVENING. THE OTHER CONCERN IS WITH
PWATS AROUND 2 INCHES...AND SURFACE DEW POINTS NEAR
70...THUNDERSTORMS WILL BE CAPABLE OF VERY HEAVY RAINFALL AND AS
MCS DEVELOPS...FLOODING WILL ALSO BE A CONCERN. MODEL CONSENSUS IS
TO PLACE HEAVIEST QPF NORTH OF THE BOUNDARY OVER THE RFD AND
CHICAGO AREAS. SEE HYDRO SECTION OF THE AFD BELOW.
AFTER THE PASSAGE OF THIS SYSTEM...CENTRAL US RIDGE SHARPENS
BRINGING MUCH DRIER AND COOLER NORTHWEST FLOW FOR THU AND FRI.
EVENTUALLY PACNW UPPER LOW MOVES EAST ACROSS THE CANADIAN PRAIRIES
WHICH WILL PUSH THE RIDGE AXIS EASTWARD AND FLATTEN IT OUT. THUS A
FEW MORE ROUNDS OF THUNDERSTORMS ARE LIKELY TO RETURN SATURDAY AND
SUNDAY AND POSSIBLY INTO MONDAY BEFORE UPPER LOW OPENS INTO A
POTENT SHORT WAVE AND DROPS SOUTHEAST THROUGH THE GREAT LAKES.
ALLSOPP
&&
.HYDROLOGY...
HAVE ISSUED A FLASH FLOOD WATCH FOR AREAS GENERALLY NORTH OF A
DIXON TO VALPARAISO LINE. THERE IS THE POTENTIAL FOR WIDESPREAD HEAVY
RAINFALL OF 2 TO 3 INCHES ACROSS THIS AREA...WITH LOCALLY UP TO 5
INCHES. THE AXIS OF HEAVIEST RAIN WILL BE OVER THE HIGHLY
URBANIZED ROCKFORD AND CHICAGO METRO AREAS. ALSO CONCERNED FOR THE
POTENTIAL OF VERY HIGH RAINFALL RATES IN SOME OF THE HEAVIER DOWNPOURS.
ALLSOPP
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 20Z...
* STRONG/SEVERE THUNDERSTORM POTENTIAL LATE THIS AFTERNOON INTO
THIS EVENING THAT COULD HAVE SIGNIFICANT IMPACTS ON THE
TERMINALS...SHOWERS/THUNDERSTORMS INCREASING AFTER 21Z.
* POTENTIAL FOR VERY HEAVY RAIN THIS EVENING...WITH IFR/LIFR VIS
AND IFR CIGS POSSIBLE FOR A PERIOD.
* EAST NORTHEAST WINDS...THEN INCREASING LATER THIS EVENING.
RODRIGUEZ
//DISCUSSION...UPDATED 18Z...
CONTINUE TO MONITOR THE POTENTIAL FOR SIGNIFICANT WEATHER TO AFFECT
THE TERMINALS LATER THIS AFTERNOON THROUGH THIS EVENING. ALTHOUGH
AT THIS TIME...RATHER QUIET ACROSS THE TERMINALS WITH VFR
CONDITIONS IN PLACE. WITH THE TRACK OF THE LOW THIS
MORNING...WINDS HAVE ACTUALLY BEEN ORIENTED MORE OUT OF A
SOUTHERLY DIRECTION TODAY. THIS WILL CONTINUE TO OCCUR WITH SOME
SPORADIC GUSTS BUT WITH A SHIFT BACK TO THE EAST NORTHEAST BY MID
AFTERNOON...WITH WINDS REMAINING MORE NORTHERLY THROUGH THE END OF
THE FORECAST PERIOD. DO EXPECT AN INCREASE IN ACTIVITY BY MID
AFTERNOON WITH SCATTERED SHOWERS/THUNDERSTORMS EXPECTED TO DEVELOP
ACROSS THE TERMINALS. THIS INITIAL ONSET IS EXPECTED TO ONLY HAVE
LIMITED IMPACTS ON THE TERMINALS BUT WITH THIS TO QUICKLY CHANGE
AS WE GO INTO THE LATE AFTERNOON. THUNDERSTORM DEVELOPMENT WILL
INCREASE WITH COVERAGE/INTENSITY OF THESE STORMS ALSO INCREASING
AS THEY SHIFT EAST ACROSS THE TERMINALS. NOT ONLY WILL LOWER
VIS/CEILINGS IN HEAVY RAIN WILL BE POSSIBLE...BUT STRONG/SHIFTING
WINDS ARE DEFINITELY POSSIBLE WITH THE STRONGEST THUNDERSTORMS
LATER THIS AFTERNOON. THIS WILL HAVE TO BE ADDRESSED WITH LATER
AMENDMENTS ONCE THUNDERSTORM INITIATION OCCURS AND THE FULL
THREAT OF CHANGING WEATHER FOR THE TERMINALS IS KNOWN.
SHOWERS/ISOLATED THUNDER SHOULD DIMINISH LATE THIS EVENING THROUGH
OVERNIGHT...WITH DRIER CONDITIONS EXPECTED EARLY THURSDAY MORNING
AS WELL AS CEILINGS IMPROVING.
RODRIGUEZ
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
* MEDIUM TO HIGH CONFIDENCE WITH THUNDERSTORM TRENDS THIS
AFTERNOON THROUGH TONIGHT.
* MEDIUM TO HIGH CONFIDENCE IN A PERIOD OF VERY HEAVY RAINFALL
WITH LOWER VIS AND CIGS THIS EVENING.
* MEDIUM CONFIDENCE IN WIND SPEED AND DIRECTION.
RODRIGUEZ
//OUTLOOK FOR ORD/MDW FOR 00Z FRIDAY-12Z WEDNESDAY...UPDATED 12Z...
THURSDAY NIGHT AND FRIDAY...VFR. WX NIL.
SAT THRU MON...VFR. CHC TSRA WITH LOCAL MVFR/IFR.
TUESDAY...VFR.
KJB
&&
.MARINE...
229 AM CDT
THE MAIN FORECAST CONCERNS ON THE LAKE IS THE THREAT FOR SEVERE
THUNDERSTORMS THIS AFTERNOON AND EVENING...ESPECIALLY ACROSS
SOUTHERN LAKE MICHIGAN...AND ALSO A PERIOD OF STRONG NORTHERLY WINDS
LATE TONIGHT AND ON THURSDAY.
DENSE FOG REMAINS ACROSS THE LAKE...ESPECIALLY ACROSS THE NORTHERN
HALF OF THE LAKE....AND I REALLY DONT SEE ANY IMPROVEMENT IN THESE
CONDITIONS UNTIL EITHER LATE THIS AFTERNOON OR THIS EVENING...WHEN
THE WINDS START TO BECOME NORTHERLY. THEREFORE...I HAVE EXTENDED THE
ADVISORY FOR THE OPEN WATERS THROUGH THIS AFTERNOON.
SEVERE THUNDERSTORMS LOOK TO BE A GOOD BET THIS AFTERNOON AND
EVENING...ESPECIALLY ACROSS SOUTHERN LAKE MICHGAN. THESE STORMS WILL
BE CAPABLE OF PRODUCING VERY LARGE HAIL AND STRONG DAMAGING WINDS
IN EXCESS OF 50 KT. THE THREAT OF SEVERE STORMS IS QUITE HIGH...SO
KEEP UP TO DATE ON THE LATEST WEATHER INFORMATION.
A SURFACE LOW IS EXPECTED TO PASS SOUTH OF THE LAKE TONIGHT. THIS
WILL SET UP SOME STRONG NORTHERLY WINDS UP TO 30 KT LATE TONIGHT AND
ON THURSDAY. THIS WILL LIKELY RESULT IN SMALL CRAFT ADVISORY
CONDITIONS FOR THE ILLINOIS AND INDIANA NEAR SHORE WATERS DURING THIS
TIME. CONDITIONS SHOULD BEGIN TO IMPROVE ON FRIDAY AS THE WINDS
ABATE AS A SURFACE RIDGE OF HIGH PRESSURE BUILDS ACROSS THE
LAKE.
KJB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...FLASH FLOOD WATCH...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-ILZ010-
ILZ011-ILZ012-ILZ013-ILZ014-ILZ020-ILZ022 UNTIL 4 AM
THURSDAY.
IN...FLASH FLOOD WATCH...INZ001-INZ002 UNTIL 4 AM THURSDAY.
LM...DENSE FOG ADVISORY...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-
LMZ565-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-
LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 4 PM
WEDNESDAY.
SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742...1 AM THURSDAY TO 4
PM THURSDAY.
SMALL CRAFT ADVISORY...LMZ743-LMZ744-LMZ745...4 AM THURSDAY TO
11 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...UPDATED
NWS CHICAGO/ROMEOVILLE IL
244 PM CDT WED JUN 12 2013
.MESOSCALE DISCUSSION...
243 PM CDT
COUPLE QUICK THOUGHTS ON SOME EVOLUTIONS IN THE MESOSCALE
ENVIRONMENT IN THE PAST 60 TO 90 MINS. DEEPER MIXING IN THE WARM
SECTOR IS ALLOWING SFC WINDS TO VEER CONSIDERABLY ACROSS THE WARM
SECTOR...WHICH IS SIGNIFICANTLY LOWERING THE LOW LEVEL SHEAR AND
POTENTIAL FOR LONG TRACK OR SIGNIFICANT TORNADOES IN THE WARM
SECTOR. WILL NEED TO MONITOR FOR ANY BACKING OF LOW LEVEL FLOW IN
THE WARM SECTOR THIS EVENING...BUT AT THIS POINT IN OUR CWA THE
MORE SIGNIFICANT TORNADO AND HIGH END WIND DAMAGE THREAT WOULD
LIKELY END UP NEAR THE SFC BOUNDARY STALLED OUT FROM ROUGHLY NEAR
CHICAGO WNW TO DBQ. THIS BOUNDARY MAY YET FLUCTUATE SOME THIS
AFTERNOON...BUT WHERE EVER THIS BOUNDARY ENDS UP IS WHERE THE
HIGHEST END SEVERE THREAT WILL LIKELY EXIST WITH SUPERCELL OR MORE
LIKELY WITH STRONG MV`S ALONG LEADING EDGE OF BOW THIS EVENING.
THE 1800 UTC SOUNDINGS FROM DVN AND ILX STILL SHOW A STRONG CAP
PRESENT...HOWEVER COMPARISON OF BOTH SOUNDINGS SHOW EVIDENCE OF
ASCENT TAKING PLACE AND BEGINNING TO LIFT THROUGH THE CAP. ALSO
SEEING EVIDENCE OF THIS ON VISIBLE SATELLITE IMAGERY WITH
GRADUALLY DEEPENING CU FIELD OVER NW IL. HAVE BEGUN TO SEE
CONVECTIVE INITIATION OVER NE IA ALREADY AND EXPECT MORE EXPLOSIVE
SEVERE THUNDERSTORM DEVELOPMENT TO TAKE PLACE WITHIN THE NEXT HOUR
OR TWO.
IZZI
130 PM CDT
THE MAIN THOUGHTS ON THE THREATS AND TIMING ON THE LIKELY SEVERE
WEATHER OUTBREAK REMAIN SIMILAR.
VISIBLE SATELLITE INDICATES MORE AGITATION IN THE ACCAS IN WEST-
TO-EAST BANDS ACROSS THE AREA WITH LIGHT ECHOES CONTINUING ON THE
RADAR MOSAIC. THESE ARE SIGNS OF THE ELEVATED WARM AIR ADVECTION
AND ACTUALLY ALREADY SOME MAMMATUS HAVE BEEN SEEN. STEEP LAPSE
RATES SEEN ON AMDAR DATA AND THE 18Z DVN RAOB ABOVE THIS LAYER
COULD SUPPORT SCATTERED CONVECTION DEVELOPING ACROSS NORTHERN IL
AND FAR NORTHWEST IN WITHIN THE NEXT TWO TO THREE HOURS.
OF GREATER CONCERN IS CONVECTIVE DEVELOPMENT LIKELY OVER NORTHEAST
IA/SOUTHWEST WI/NORTHWEST IL. THE PRIMARY 1004MB SURFACE LOW
ACROSS CENTRAL IA CONTINUES TO DEVELOP EAST WITH 5 MB/3 HR
PRESSURE FALLS CENTERED OVER THE CWA WHERE THE WARM FRONTAL
BOUNDARY HAS POSITIONED ITSELF. THIS BOUNDARY HAS UNDULATED
SOME...BUT APPEARS TO BE NORTH OF I-88 ESE INTO THE CHICAGO METRO
AREA...AND WILL POTENTIALLY BECOME MORE DEFINED WITH CLEARING
OCCURING ACROSS THE SOUTHERN FORECAST AREA. PRONOUNCED DRYING ON
WATER VAPOR AHEAD OF THE MAIN SHORT WAVE IN SOUTHERN MN AND A MID-
LEVEL WIND MAX WILL CONTINUE TO MOVE EAST AND OVERRIDE THE WARM
FRONTAL REGION ACROSS EASTERN IA SHORTLY. THE DEVELOPMENT OF
CONVECTION SEEN ON HIGH RESOLUTION GUIDANCE ALONG AND NORTH OF THE
WARM FRONT IN THIS AREA IS SUPPORTED BY OBSERVATIONAL
TRENDS...WITH THE DVN RAOB AND RAP ANALYSIS HAVING INDICATED THE
CAP TO BE ERODED.
THIS LIKELY DISCRETE DEVELOPMENT AT FIRST WILL AGAIN EVOLVE EAST
ACROSS NORTH CENTRAL IL AFTER MAINLY 4 PM. THE INSTABILITY AND
SHEAR SPECTRUM OF THE CURRENT ATMOSPHERE ARE NO PROBLEMS FOR
SEVERE STORMS...WITH HIGH CAPE GREATER THAN 2500 J/KG AND
EFFECTIVE DEEP LAYER SHEAR IN EXCESS OF 45 KTS. SUPERCELLS WILL
CERTAINLY BE SUPPORTED. SOME DEVELOPMENT EAST OF THE INITIAL
CELLS...POSSIBLY SURFACE BASED...MAY OCCUR TOO DEPENDING ON IF THE
CIN CAN ERODE AND THE CONVERGENCE ALONG THE SURFACE BOUNDARY IS
ENHANCED. THIS LENDS TO UNCERTAINTY ON WHEN THE FIRST ROBUST
ACTIVITY COULD REACH CHICAGO. BUT THE PRIMARY THREAT TIMES STILL
LOOK TO BE 4-7 PM IN AND AROUND ROCKFORD AND 6-11 PM IN CHICAGO.
OBSERVATIONAL TRENDS CONTINUE TO POINT TOWARDS THE POTENTIAL FOR A
ROBUST MCS...WITH WINDS POTENTIALLY 80 TO 100 MPH WINDS...DEVELOPING
ACROSS THE AREA THIS EVE. ALL INGREDIENTS ARE FAVORABLE FOR
THIS...INCLUDING A STRONG MID-LEVEL JET...SUFFICIENT 0-3 KM SHEAR
FOR COLD POOL ORGANIZATION...A LARGE AREA OF HIGH DOWNDRAFT
CAPE...AND A VEERING STRONG LOW-LEVEL JET INTO A EXISTING
BAROCLINIC GRADIENT. MANY OF THE CONVECTIVE ALLOWING GUIDANCE
INDICATE NOT ONLY MCV TYPE STRUCTURE ACROSS FAR NORTHERN IL RACING
INTO CHICAGO AND NORTHWEST IN THIS EVE...BUT ALSO AGREE ON HIGH
SURFACE-BASED WINDS. RAP AND NAM FORECASTS INTO TONIGHT FOR THE
ENVIRONMENT WOULD SUPPORT THIS AS WOULD THE CONCEPTUAL MODEL OF A
QUICKLY EASTWARD DEVELOPING SURFACE LOW. SOMETHING TO KEEP IN MIND
WITH THE POSSIBLE PATH OF THIS ACROSS FAR SOUTHERN LAKE MI IS THAT
A SEICHE WOULD BE FAVORED IF THAT WERE TO OCCUR. THE 12Z LOCAL ARW
ACTUALLY APPEARS TO HAVE THAT FORECAST IN THE PRESSURE FIELDS.
WILL MENTION THIS AND THE HIGHER ENDS WINDS OVER LAND IN THE HWO.+
&&
.DISCUSSION...
304 AM CDT
...MAJOR SEVERE WEATHER OUTBREAK LIKELY THIS AFTERNOON AND
EVENING...WITH HEAVY RAINFALL ALSO LIKELY...
EVERYTHING LINING UP FOR A SIGNIFICANT SEVERE WEATHER OUTBREAK
TODAY. SPC DAY 1 OUTLOOK HAS ENTIRE FORECAST AREA IN MODERATE RISK
OF SEVERE WITH SIGNIFICANT WIND...HAIL...AND TORNADO THREAT. AT THE
SURFACE...LOW PRESSURE OVER THE PLAINS WITH A WEAK WARM FRONT
EXTENDING EAST INTO NORTHERN IL EARLY THIS MORNING. THE LOW WILL
MOVE EAST ALONG THE IA/MO BOARDER TODAY...AND ACROSS NORTHERN IL
THIS EVENING. VERY MOIST LOW LEVEL AIR WITH SURFACE DEW POINTS IN
THE MID AND UPPER 60S IN PLACE. MAY SEE DEWPOINTS POOL IN THE LOWER
70S SOUTH OF WARM FRONT THIS AFTERNOON. THE BOUNDARY WILL INTENSIFY
AS SOUTHWEST LOW LEVEL FLOW INCREASES SOUTH OF THE FRONT AND SURFACE
WINDS BACK TO SE OR E NORTH OF THE BOUNDARY. THIS WILL PULL MODIFIED
MARINE AIR BACK ACROSS FAR NORTHERN IL. HAVE SOME CONCERNS ABOUT HOW
FAR NORTH THE WARM FRONT WILL TRAVEL. SPC DISCUSSION SUGGESTING THE
BOUNDARY WILL MOVE INTO SOUTHERN WI BUT WITH MODELS TAKING LOW
ACROSS I-80 CORRIDOR AND COOLING INFLUENCE OF LAKE
MICHIGAN...THINKING FRONT WONT GET MUCH FARTHER NORTH THAN A
DIXON-GARY LINE. THIS MAY LIMIT NORTHERN EXTEND OF SIGNIFICANT
SEVERE THREAT. THE BOUNDARY WILL ALSO RESULT IN A CHALLENGING
TEMPERATURE FORECAST...WITH TEMPS REACHING LOWER 90S FAR SOUTHERN
PART OF FORECAST AREA...WHILE AREAS ALONG THE NORTH SHORE WILL
LIKELY BE 20 DEGREES COOLER. IT APPEARS THAT MOST OF THE OVERNIGHT
EARLY MORNING CONVECTION WILL AFFECT WI...BUT KEEPING AN EYE ON
MCS OVER WESTERN IA WHICH COULD MOVE INTO NORTHERN IL THIS
MORNING. EARLIER CONVECTION OVER EASTERN IA WEAKENED AS IT MOVED
EAST AND THINK THIS MCS MAY DO THE SAME. CLOUD DEBRIS SHOULD
REMAIN NORTH ALLOWING AREAS SOUTH OF THE WARM FRONT TO HEAT UP
SIGNIFICANTLY...INTO THE UPPER 80S TO LOWER 90S. THIS COULD RESULT
IN SURFACE BASED CAPE OF 3000+ THIS AFTERNOON. FAIRLY VIGOROUS
SHORT WAVE MOVING INTO WESTERN SD/NE EARLY THIS MORNING WILL BE
MOVING ACROSS NORTHERN IL THIS EVENING. MODEL SOUNDINGS SHOW
FAIRLY STOUT CAP EARLY IN THE DAY ERODES THIS AFTERNOON WITH
APPROACHING SHORT WAVE. LOOKING AT 0-6KM BULK SHEAR 50-60 KTS BY
THIS EVENING. WITH INCREASING LOW LEVEL FLOW THIS AFTERNOON AND
BACKING SURFACE WINDS ALONG THE BOUNDARY...SHOULD PRODUCE AN
ENVIRONMENT FAVORABLE FOR DAMAGING WINDS...LARGE HAIL...AND
TORNADOES. SOME OF THE SHORT RANGE HI RES GUIDANCE IS SUGGESTING
DISCRETE STORMS INITIALLY THIS AFTERNOON. EXPECT THE TORNADO
THREAT TO BE MAINLY DURING THE AFTERNOON. STORMS WILL LIKELY
CONGEAL INTO AN MCS AND BECOME MORE OF A HIGH WIND WITH EMBEDDED
QLCS TORNADO THREAT IN THE EVENING. THE OTHER CONCERN IS WITH
PWATS AROUND 2 INCHES...AND SURFACE DEW POINTS NEAR
70...THUNDERSTORMS WILL BE CAPABLE OF VERY HEAVY RAINFALL AND AS
MCS DEVELOPS...FLOODING WILL ALSO BE A CONCERN. MODEL CONSENSUS IS
TO PLACE HEAVIEST QPF NORTH OF THE BOUNDARY OVER THE RFD AND
CHICAGO AREAS. SEE HYDRO SECTION OF THE AFD BELOW.
AFTER THE PASSAGE OF THIS SYSTEM...CENTRAL US RIDGE SHARPENS
BRINGING MUCH DRIER AND COOLER NORTHWEST FLOW FOR THU AND FRI.
EVENTUALLY PACNW UPPER LOW MOVES EAST ACROSS THE CANADIAN PRAIRIES
WHICH WILL PUSH THE RIDGE AXIS EASTWARD AND FLATTEN IT OUT. THUS A
FEW MORE ROUNDS OF THUNDERSTORMS ARE LIKELY TO RETURN SATURDAY AND
SUNDAY AND POSSIBLY INTO MONDAY BEFORE UPPER LOW OPENS INTO A
POTENT SHORT WAVE AND DROPS SOUTHEAST THROUGH THE GREAT LAKES.
ALLSOPP
&&
.HYDROLOGY...
HAVE ISSUED A FLASH FLOOD WATCH FOR AREAS GENERALLY NORTH OF A
DIXON TO VALPARAISO LINE. THERE IS THE POTENTIAL FOR WIDESPREAD HEAVY
RAINFALL OF 2 TO 3 INCHES ACROSS THIS AREA...WITH LOCALLY UP TO 5
INCHES. THE AXIS OF HEAVIEST RAIN WILL BE OVER THE HIGHLY
URBANIZED ROCKFORD AND CHICAGO METRO AREAS. ALSO CONCERNED FOR THE
POTENTIAL OF VERY HIGH RAINFALL RATES IN SOME OF THE HEAVIER DOWNPOURS.
ALLSOPP
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 18Z...
* STRONG/SEVERE THUNDERSTORM POTENTIAL LATE THIS AFTERNOON INTO
THIS EVENING THAT COULD HAVE SIGNIFICANT IMPACTS ON THE
TERMINALS...SHOWERS/THUNDERSTORMS INCREASING AFTER 20Z.
* POTENTIAL FOR VERY HEAVY RAIN THIS EVENING...WITH IFR/LIFR VIS
AND IFR CIGS POSSIBLE FOR A PERIOD.
* SOUTHERLY WINDS WITH GUSTS IN THE MID/UPPER TEENS POSSIBLE
BEFORE WINDS ARE EXPECTED TO GO BACK TO THE EAST NORTHEAST BY
MID AFTERNOON...THEN INCREASING OUT OF THE NORTH/NORTHEAST THIS
EVENING.
RODRIGUEZ
//DISCUSSION...UPDATED 18Z...
CONTINUE TO MONITOR THE POTENTIAL FOR SIGNIFICANT WEATHER TO AFFECT
THE TERMINALS LATER THIS AFTERNOON THROUGH THIS EVENING. ALTHOUGH
AT THIS TIME...RATHER QUIET ACROSS THE TERMINALS WITH VFR
CONDITIONS IN PLACE. WITH THE TRACK OF THE LOW THIS
MORNING...WINDS HAVE ACTUALLY BEEN ORIENTED MORE OUT OF A
SOUTHERLY DIRECTION TODAY. THIS WILL CONTINUE TO OCCUR WITH SOME
SPORADIC GUSTS BUT WITH A SHIFT BACK TO THE EAST NORTHEAST BY MID
AFTERNOON...WITH WINDS REMAINING MORE NORTHERLY THROUGH THE END OF
THE FORECAST PERIOD. DO EXPECT AN INCREASE IN ACTIVITY BY MID
AFTERNOON WITH SCATTERED SHOWERS/THUNDERSTORMS EXPECTED TO DEVELOP
ACROSS THE TERMINALS. THIS INITIAL ONSET IS EXPECTED TO ONLY HAVE
LIMITED IMPACTS ON THE TERMINALS BUT WITH THIS TO QUICKLY CHANGE
AS WE GO INTO THE LATE AFTERNOON. THUNDERSTORM DEVELOPMENT WILL
INCREASE WITH COVERAGE/INTENSITY OF THESE STORMS ALSO INCREASING
AS THEY SHIFT EAST ACROSS THE TERMINALS. NOT ONLY WILL LOWER
VIS/CEILINGS IN HEAVY RAIN WILL BE POSSIBLE...BUT STRONG/SHIFTING
WINDS ARE DEFINITELY POSSIBLE WITH THE STRONGEST THUNDERSTORMS
LATER THIS AFTERNOON. THIS WILL HAVE TO BE ADDRESSED WITH LATER
AMENDMENTS ONCE THUNDERSTORM INITIATION OCCURS AND THE FULL
THREAT OF CHANGING WEATHER FOR THE TERMINALS IS KNOWN.
SHOWERS/ISOLATED THUNDER SHOULD DIMINISH LATE THIS EVENING THROUGH
OVERNIGHT...WITH DRIER CONDITIONS EXPECTED EARLY THURSDAY MORNING
AS WELL AS CEILINGS IMPROVING.
RODRIGUEZ
//ORD AND MDW CONFIDENCE...UPDATED 18Z...
* MEDIUM TO HIGH CONFIDENCE IN CHANCES FOR THUNDERSTORMS LATER
TODAY AND TONIGHT...BUT MEDIUM CONFIDENCE ON THE ONSET TIMING.
* MEDIUM TO HIGH CONFIDENCE IN A PERIOD OF VERY HEAVY RAINFALL
WITH LOWER VIS AND CIGS THIS EVENING.
* MEDIUM CONFIDENCE IN WIND SPEED AND DIRECTION.
RODRIGUEZ
//OUTLOOK FOR ORD/MDW FOR 00Z FRIDAY-12Z WEDNESDAY...UPDATED 12Z...
THURSDAY NIGHT AND FRIDAY...VFR. WX NIL.
SAT THRU MON...VFR. CHC TSRA WITH LOCAL MVFR/IFR.
TUESDAY...VFR.
KJB
&&
.MARINE...
229 AM CDT
THE MAIN FORECAST CONCERNS ON THE LAKE IS THE THREAT FOR SEVERE
THUNDERSTORMS THIS AFTERNOON AND EVENING...ESPECIALLY ACROSS
SOUTHERN LAKE MICHIGAN...AND ALSO A PERIOD OF STRONG NORTHERLY WINDS
LATE TONIGHT AND ON THURSDAY.
DENSE FOG REMAINS ACROSS THE LAKE...ESPECIALLY ACROSS THE NORTHERN
HALF OF THE LAKE....AND I REALLY DONT SEE ANY IMPROVEMENT IN THESE
CONDITIONS UNTIL EITHER LATE THIS AFTERNOON OR THIS EVENING...WHEN
THE WINDS START TO BECOME NORTHERLY. THEREFORE...I HAVE EXTENDED THE
ADVISORY FOR THE OPEN WATERS THROUGH THIS AFTERNOON.
SEVERE THUNDERSTORMS LOOK TO BE A GOOD BET THIS AFTERNOON AND
EVENING...ESPECIALLY ACROSS SOUTHERN LAKE MICHGAN. THESE STORMS WILL
BE CAPABLE OF PRODUCING VERY LARGE HAIL AND STRONG DAMAGING WINDS
IN EXCESS OF 50 KT. THE THREAT OF SEVERE STORMS IS QUITE HIGH...SO
KEEP UP TO DATE ON THE LATEST WEATHER INFORMATION.
A SURFACE LOW IS EXPECTED TO PASS SOUTH OF THE LAKE TONIGHT. THIS
WILL SET UP SOME STRONG NORTHERLY WINDS UP TO 30 KT LATE TONIGHT AND
ON THURSDAY. THIS WILL LIKELY RESULT IN SMALL CRAFT ADVISORY
CONDITIONS FOR THE ILLINOIS AND INDIANA NEAR SHORE WATERS DURING THIS
TIME. CONDITIONS SHOULD BEGIN TO IMPROVE ON FRIDAY AS THE WINDS
ABATE AS A SURFACE RIDGE OF HIGH PRESSURE BUILDS ACROSS THE
LAKE.
KJB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...FLASH FLOOD WATCH...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-ILZ010-
ILZ011-ILZ012-ILZ013-ILZ014-ILZ020-ILZ022 UNTIL 4 AM
THURSDAY.
IN...FLASH FLOOD WATCH...INZ001-INZ002 UNTIL 4 AM THURSDAY.
LM...DENSE FOG ADVISORY...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-
LMZ565-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-
LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 4 PM
WEDNESDAY.
SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742...1 AM THURSDAY TO 4
PM THURSDAY.
SMALL CRAFT ADVISORY...LMZ743-LMZ744-LMZ745...4 AM THURSDAY TO
11 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...UPDATED
NWS CHICAGO/ROMEOVILLE IL
129 PM CDT WED JUN 12 2013
.MESOSCALE DISCUSSION...
130 PM CDT
THE MAIN THOUGHTS ON THE THREATS AND TIMING ON THE LIKELY SEVERE
WEATHER OUTBREAK REMAIN SIMILAR.
VISIBLE SATELLITE INDICATES MORE AGITATION IN THE ACCAS IN WEST-
TO-EAST BANDS ACROSS THE AREA WITH LIGHT ECHOES CONTINUING ON THE
RADAR MOSAIC. THESE ARE SIGNS OF THE ELEVATED WARM AIR ADVECTION
AND ACTUALLY ALREADY SOME MAMMATUS HAVE BEEN SEEN. STEEP LAPSE
RATES SEEN ON AMDAR DATA AND THE 18Z DVN RAOB ABOVE THIS LAYER
COULD SUPPORT SCATTERED CONVECTION DEVELOPING ACROSS NORTHERN IL
AND FAR NORTHWEST IN WITHIN THE NEXT TWO TO THREE HOURS.
OF GREATER CONCERN IS CONVECTIVE DEVELOPMENT LIKELY OVER NORTHEAST
IA/SOUTHWEST WI/NORTHWEST IL. THE PRIMARY 1004MB SURFACE LOW
ACROSS CENTRAL IA CONTINUES TO DEVELOP EAST WITH 5 MB/3 HR
PRESSURE FALLS CENTERED OVER THE CWA WHERE THE WARM FRONTAL
BOUNDARY HAS POSITIONED ITSELF. THIS BOUNDARY HAS UNDULATED
SOME...BUT APPEARS TO BE NORTH OF I-88 ESE INTO THE CHICAGO METRO
AREA...AND WILL POTENTIALLY BECOME MORE DEFINED WITH CLEARING
OCCURING ACROSS THE SOUTHERN FORECAST AREA. PRONOUNCED DRYING ON
WATER VAPOR AHEAD OF THE MAIN SHORT WAVE IN SOUTHERN MN AND A MID-
LEVEL WIND MAX WILL CONTINUE TO MOVE EAST AND OVERRIDE THE WARM
FRONTAL REGION ACROSS EASTERN IA SHORTLY. THE DEVELOPMENT OF
CONVECTION SEEN ON HIGH RESOLUTION GUIDANCE ALONG AND NORTH OF THE
WARM FRONT IN THIS AREA IS SUPPORTED BY OBSERVATIONAL
TRENDS...WITH THE DVN RAOB AND RAP ANALYSIS HAVING INDICATED THE
CAP TO BE ERODED.
THIS LIKELY DISCRETE DEVELOPMENT AT FIRST WILL AGAIN EVOLVE EAST
ACROSS NORTH CENTRAL IL AFTER MAINLY 4 PM. THE INSTABILITY AND
SHEAR SPECTRUM OF THE CURRENT ATMOSPHERE ARE NO PROBLEMS FOR
SEVERE STORMS...WITH HIGH CAPE GREATER THAN 2500 J/KG AND
EFFECTIVE DEEP LAYER SHEAR IN EXCESS OF 45 KTS. SUPERCELLS WILL
CERTAINLY BE SUPPORTED. SOME DEVELOPMENT EAST OF THE INITIAL
CELLS...POSSIBLY SURFACE BASED...MAY OCCUR TOO DEPENDING ON IF THE
CIN CAN ERODE AND THE CONVERGENCE ALONG THE SURFACE BOUNDARY IS
ENHANCED. THIS LENDS TO UNCERTAINTY ON WHEN THE FIRST ROBUST
ACTIVITY COULD REACH CHICAGO. BUT THE PRIMARY THREAT TIMES STILL
LOOK TO BE 4-7 PM IN AND AROUND ROCKFORD AND 6-11 PM IN CHICAGO.
OBSERVATIONAL TRENDS CONTINUE TO POINT TOWARDS THE POTENTIAL FOR A
ROBUST MCS...WITH WINDS POTENTIALLY 80 TO 100 MPH WINDS...DEVELOPING
ACROSS THE AREA THIS EVE. ALL INGREDIENTS ARE FAVORABLE FOR
THIS...INCLUDING A STRONG MID-LEVEL JET...SUFFICIENT 0-3 KM SHEAR
FOR COLD POOL ORGANIZATION...A LARGE AREA OF HIGH DOWNDRAFT
CAPE...AND A VEERING STRONG LOW-LEVEL JET INTO A EXISTING
BAROCLINIC GRADIENT. MANY OF THE CONVECTIVE ALLOWING GUIDANCE
INDICATE NOT ONLY MCV TYPE STRUCTURE ACROSS FAR NORTHERN IL RACING
INTO CHICAGO AND NORTHWEST IN THIS EVE...BUT ALSO AGREE ON HIGH
SURFACE-BASED WINDS. RAP AND NAM FORECASTS INTO TONIGHT FOR THE
ENVIRONMENT WOULD SUPPORT THIS AS WOULD THE CONCEPTUAL MODEL OF A
QUICKLY EASTWARD DEVELOPING SURFACE LOW. SOMETHING TO KEEP IN MIND
WITH THE POSSIBLE PATH OF THIS ACROSS FAR SOUTHERN LAKE MI IS THAT
A SEICHE WOULD BE FAVORED IF THAT WERE TO OCCUR. THE 12Z LOCAL ARW
ACTUALLY APPEARS TO HAVE THAT FORECAST IN THE PRESSURE FIELDS.
WILL MENTION THIS AND THE HIGHER ENDS WINDS OVER LAND IN THE HWO.+
.MESOSCALE DISCUSSION...
1042 AM CDT
...WIDESPREAD SEVERE WEATHER OUTBREAK ACROSS THE REGION EXPECTED
LATE THIS AFTERNOON AND EVENING INCLUDING TORNADIC POTENTIAL IN
NORTH CENTRAL IL LATE THIS AFTERNOON...
SEVERE WEATHER THREAT CONTINUES WITH OBSERVATIONAL TRENDS HINTING
MORE AT PRECISE EVOLUTION AND TIMING.
WHAT LEFTS OF OVERNIGHT DECAYING MCS IS MOVING FROM SOUTHEAST WI
OVER LAKE MI. VISIBLE SATELLITE AND REGIONAL RADAR MOSAIC
INDICATE SOME BRIEF SUPPRESSION BEHIND THIS WHILE THERE IS AN AXIS
EXTENDING SOUTHWARD ON RADAR OF LIKELY SOME MID-LEVEL CONVERGENCE.
THERE HAS NOT BEEN ANY DEVELOPMENT ALONG THIS THUS FAR BUT CANNOT
RULE OUT A FEW ELEVATED STORMS THROUGH 3 PM OR SO ACROSS FAR
NORTHERN AND NORTHEAST IL.
THE SURFACE LOW PRESSURE IS DEVELOPING NORTHEASTWARD INTO SOUTHWEST
AND CENTRAL IA AS OF 10 AM WITH A WARM FRONT EVOLVING EAST
NORTHEAST FROM THERE. THIS LOOKS TO BE FROM NEAR WATERLOO IA TO
SAVANNA IL AND THEN BECOMING MORE ILL-DEFINED EAST OF THERE INTO
THE CWA. DEW POINTS IN THE LOWER 70S ARE ADVECTING UP TO THIS
BOUNDARY WITH WINDS STRONGLY BACKED TO THE NORTH OF THIS. THERE
HAS BEEN GROWTH IN THE CU ACROSS IA NEAR THIS DEVELOPING FRONT.
AS THE MAIN VORT MAX AND MID-LEVEL SPEED MAX MOVE EAST FROM
EASTERN SD/NORTHEAST NE...DEVELOPMENT OF ROBUST CONVECTION IS
HIGHLY LIKELY BY MID AFTERNOON ACROSS NE IA/SW WI/NW IL. SUPERCELL
DEVELOPMENT WOULD BE A FAVORED MODE ALONG AND IMMEDIATELY NORTH OF
THE WARM FRONT. FURTHER NORTH AND NORTHEAST FROM THE TWIN CITIES
TO MILWAUKEE...ELEVATED CONVECTION MAY INCREASE. ALL OF THIS IS
SLIGHTLY FURTHER NORTH THAN EARLIER ANTICIPATED...BUT THE SEVERE
WEATHER THREAT HAS NOT DIMINISHED FOR OUR AREA...JUST FOCUSED MORE
SO IN THE LATE AFTERNOON AND EVE.
GIVEN THE ANTICIPATED EVOLUTION MENTIONED ABOVE WHICH HAS THE
SUPPORT OF THE RAP AND SEVERAL CONVECTIVE-ALLOWING MODELS...NORTH
CENTRAL IL WILL LIKELY BE UNDER THE GUN LATE THIS AFTERNOON. THIS
INCLUDES THE ROCKFORD AREA DURING RUSH HOUR AS STORMS EVOLVE
EASTWARD IN A FAVORED COMBINATION OF DISCRETE TO SMALL SCALE
CLUSTERS. TORNADIC POTENTIAL WILL CERTAINLY EXIST WITH THESE GIVEN
THE HELICITY RICH AIR NEAR THE BOUNDARY AND ANTICIPATED SURFACE-
BASED CAPE. CONVECTIVE TEMPERATURES FOR THIS ARE FORECAST TO BE
AROUND 80 DEGREES ON THE RAP. WHILE TEMPERATURE TRENDS HAVE BEEN
SLOW TO CLIMB ACROSS THE AREA THUS FAR...SOME THINNING OF THE
CLOUDS AND THE NORTHWARD PUSH OF THE WARM SECTOR SHOULD ALLOW THAT
TO OCCUR.
THE EVENING TIME PERIOD SHOULD SEE THE MOST COVERAGE OF SEVERE
CONVECTION IN THE FORECAST AREA AND WILL BE THE PRIME TIME FOR
CHICAGOLAND. THE LOW-LEVEL JET IS FORECAST TO INCREASE TO 40-50 KT
AND POINT INTO THE ONGOING CONVECTION. SOME SCATTERED CONVECTIVE
DEVELOPMENT...POTENTIALLY SEVERE AND SURFACE BASED...EAST AND
SOUTH OF THIS IS FAVORED DURING THE EVE. SUFFICIENT DEEP LAYER
SHEAR AND RICH LOW-LEVEL MOISTURE WILL OFFER AMPLE WIND THREAT
WITH THE ORGANIZED CONVECTIVE CLUSTERS. WITH THE SURFACE LOW
PROJECTED TO TRACK EAST NEAR THE I-88 CORRIDOR...THERE IS
INCREASING LIKELIHOOD THAT THE MAIN MCV/MCS WILL DEVELOP NEAR THIS
CORRIDOR AS WELL. A MAJORITY OF THE EXPLICIT GUIDANCE DOES
INDICATE THIS. VERY HEAVY RAINFALL AND AN ENHANCED WIND THREAT
WILL EXIST WITH THIS...WHICH WOULD LIKELY IMPACT CHICAGO IN THE
6-10 PM TIME FRAME.
MTF
&&
.DISCUSSION...
304 AM CDT
...MAJOR SEVERE WEATHER OUTBREAK LIKELY THIS AFTERNOON AND
EVENING...WITH HEAVY RAINFALL ALSO LIKELY...
EVERYTHING LINING UP FOR A SIGNIFICANT SEVERE WEATHER OUTBREAK
TODAY. SPC DAY 1 OUTLOOK HAS ENTIRE FORECAST AREA IN MODERATE RISK
OF SEVERE WITH SIGNIFICANT WIND...HAIL...AND TORNADO THREAT. AT THE
SURFACE...LOW PRESSURE OVER THE PLAINS WITH A WEAK WARM FRONT
EXTENDING EAST INTO NORTHERN IL EARLY THIS MORNING. THE LOW WILL
MOVE EAST ALONG THE IA/MO BOARDER TODAY...AND ACROSS NORTHERN IL
THIS EVENING. VERY MOIST LOW LEVEL AIR WITH SURFACE DEW POINTS IN
THE MID AND UPPER 60S IN PLACE. MAY SEE DEWPOINTS POOL IN THE LOWER
70S SOUTH OF WARM FRONT THIS AFTERNOON. THE BOUNDARY WILL INTENSIFY
AS SOUTHWEST LOW LEVEL FLOW INCREASES SOUTH OF THE FRONT AND SURFACE
WINDS BACK TO SE OR E NORTH OF THE BOUNDARY. THIS WILL PULL MODIFIED
MARINE AIR BACK ACROSS FAR NORTHERN IL. HAVE SOME CONCERNS ABOUT HOW
FAR NORTH THE WARM FRONT WILL TRAVEL. SPC DISCUSSION SUGGESTING THE
BOUNDARY WILL MOVE INTO SOUTHERN WI BUT WITH MODELS TAKING LOW
ACROSS I-80 CORRIDOR AND COOLING INFLUENCE OF LAKE
MICHIGAN...THINKING FRONT WONT GET MUCH FARTHER NORTH THAN A
DIXON-GARY LINE. THIS MAY LIMIT NORTHERN EXTEND OF SIGNIFICANT
SEVERE THREAT. THE BOUNDARY WILL ALSO RESULT IN A CHALLENGING
TEMPERATURE FORECAST...WITH TEMPS REACHING LOWER 90S FAR SOUTHERN
PART OF FORECAST AREA...WHILE AREAS ALONG THE NORTH SHORE WILL
LIKELY BE 20 DEGREES COOLER. IT APPEARS THAT MOST OF THE OVERNIGHT
EARLY MORNING CONVECTION WILL AFFECT WI...BUT KEEPING AN EYE ON
MCS OVER WESTERN IA WHICH COULD MOVE INTO NORTHERN IL THIS
MORNING. EARLIER CONVECTION OVER EASTERN IA WEAKENED AS IT MOVED
EAST AND THINK THIS MCS MAY DO THE SAME. CLOUD DEBRIS SHOULD
REMAIN NORTH ALLOWING AREAS SOUTH OF THE WARM FRONT TO HEAT UP
SIGNIFICANTLY...INTO THE UPPER 80S TO LOWER 90S. THIS COULD RESULT
IN SURFACE BASED CAPE OF 3000+ THIS AFTERNOON. FAIRLY VIGOROUS
SHORT WAVE MOVING INTO WESTERN SD/NE EARLY THIS MORNING WILL BE
MOVING ACROSS NORTHERN IL THIS EVENING. MODEL SOUNDINGS SHOW
FAIRLY STOUT CAP EARLY IN THE DAY ERODES THIS AFTERNOON WITH
APPROACHING SHORT WAVE. LOOKING AT 0-6KM BULK SHEAR 50-60 KTS BY
THIS EVENING. WITH INCREASING LOW LEVEL FLOW THIS AFTERNOON AND
BACKING SURFACE WINDS ALONG THE BOUNDARY...SHOULD PRODUCE AN
ENVIRONMENT FAVORABLE FOR DAMAGING WINDS...LARGE HAIL...AND
TORNADOES. SOME OF THE SHORT RANGE HI RES GUIDANCE IS SUGGESTING
DISCRETE STORMS INITIALLY THIS AFTERNOON. EXPECT THE TORNADO
THREAT TO BE MAINLY DURING THE AFTERNOON. STORMS WILL LIKELY
CONGEAL INTO AN MCS AND BECOME MORE OF A HIGH WIND WITH EMBEDDED
QLCS TORNADO THREAT IN THE EVENING. THE OTHER CONCERN IS WITH
PWATS AROUND 2 INCHES...AND SURFACE DEW POINTS NEAR
70...THUNDERSTORMS WILL BE CAPABLE OF VERY HEAVY RAINFALL AND AS
MCS DEVELOPS...FLOODING WILL ALSO BE A CONCERN. MODEL CONSENSUS IS
TO PLACE HEAVIEST QPF NORTH OF THE BOUNDARY OVER THE RFD AND
CHICAGO AREAS. SEE HYDRO SECTION OF THE AFD BELOW.
AFTER THE PASSAGE OF THIS SYSTEM...CENTRAL US RIDGE SHARPENS
BRINGING MUCH DRIER AND COOLER NORTHWEST FLOW FOR THU AND FRI.
EVENTUALLY PACNW UPPER LOW MOVES EAST ACROSS THE CANADIAN PRAIRIES
WHICH WILL PUSH THE RIDGE AXIS EASTWARD AND FLATTEN IT OUT. THUS A
FEW MORE ROUNDS OF THUNDERSTORMS ARE LIKELY TO RETURN SATURDAY AND
SUNDAY AND POSSIBLY INTO MONDAY BEFORE UPPER LOW OPENS INTO A
POTENT SHORT WAVE AND DROPS SOUTHEAST THROUGH THE GREAT LAKES.
ALLSOPP
&&
.HYDROLOGY...
HAVE ISSUED A FLASH FLOOD WATCH FOR AREAS GENERALLY NORTH OF A
DIXON TO VALPARAISO LINE. THERE IS THE POTENTIAL FOR WIDESPREAD HEAVY
RAINFALL OF 2 TO 3 INCHES ACROSS THIS AREA...WITH LOCALLY UP TO 5
INCHES. THE AXIS OF HEAVIEST RAIN WILL BE OVER THE HIGHLY
URBANIZED ROCKFORD AND CHICAGO METRO AREAS. ALSO CONCERNED FOR THE
POTENTIAL OF VERY HIGH RAINFALL RATES IN SOME OF THE HEAVIER DOWNPOURS.
ALLSOPP
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 18Z...
* STRONG/SEVERE THUNDERSTORM POTENTIAL LATE THIS AFTERNOON INTO
THIS EVENING THAT COULD HAVE SIGNIFICANT IMPACTS ON THE
TERMINALS...SHOWERS/THUNDERSTORMS INCREASING AFTER 20Z.
* POTENTIAL FOR VERY HEAVY RAIN THIS EVENING...WITH IFR/LIFR VIS
AND IFR CIGS POSSIBLE FOR A PERIOD.
* SOUTHERLY WINDS WITH GUSTS IN THE MID/UPPER TEENS POSSIBLE
BEFORE WINDS ARE EXPECTED TO GO BACK TO THE EAST NORTHEAST BY
MID AFTERNOON...THEN INCREASING OUT OF THE NORTH/NORTHEAST THIS
EVENING.
RODRIGUEZ
//DISCUSSION...UPDATED 18Z...
CONTINUE TO MONITOR THE POTENTIAL FOR SIGNIFICANT WEATHER TO AFFECT
THE TERMINALS LATER THIS AFTERNOON THROUGH THIS EVENING. ALTHOUGH
AT THIS TIME...RATHER QUIET ACROSS THE TERMINALS WITH VFR
CONDITIONS IN PLACE. WITH THE TRACK OF THE LOW THIS
MORNING...WINDS HAVE ACTUALLY BEEN ORIENTED MORE OUT OF A
SOUTHERLY DIRECTION TODAY. THIS WILL CONTINUE TO OCCUR WITH SOME
SPORADIC GUSTS BUT WITH A SHIFT BACK TO THE EAST NORTHEAST BY MID
AFTERNOON...WITH WINDS REMAINING MORE NORTHERLY THROUGH THE END OF
THE FORECAST PERIOD. DO EXPECT AN INCREASE IN ACTIVITY BY MID
AFTERNOON WITH SCATTERED SHOWERS/THUNDERSTORMS EXPECTED TO DEVELOP
ACROSS THE TERMINALS. THIS INITIAL ONSET IS EXPECTED TO ONLY HAVE
LIMITED IMPACTS ON THE TERMINALS BUT WITH THIS TO QUICKLY CHANGE
AS WE GO INTO THE LATE AFTERNOON. THUNDERSTORM DEVELOPMENT WILL
INCREASE WITH COVERAGE/INTENSITY OF THESE STORMS ALSO INCREASING
AS THEY SHIFT EAST ACROSS THE TERMINALS. NOT ONLY WILL LOWER
VIS/CEILINGS IN HEAVY RAIN WILL BE POSSIBLE...BUT STRONG/SHIFTING
WINDS ARE DEFINITELY POSSIBLE WITH THE STRONGEST THUNDERSTORMS
LATER THIS AFTERNOON. THIS WILL HAVE TO BE ADDRESSED WITH LATER
AMENDMENTS ONCE THUNDERSTORM INITIATION OCCURS AND THE FULL
THREAT OF CHANGING WEATHER FOR THE TERMINALS IS KNOWN.
SHOWERS/ISOLATED THUNDER SHOULD DIMINISH LATE THIS EVENING THROUGH
OVERNIGHT...WITH DRIER CONDITIONS EXPECTED EARLY THURSDAY MORNING
AS WELL AS CEILINGS IMPROVING.
RODRIGUEZ
//ORD AND MDW CONFIDENCE...UPDATED 18Z...
* MEDIUM TO HIGH CONFIDENCE IN CHANCES FOR THUNDERSTORMS LATER
TODAY AND TONIGHT...BUT MEDIUM CONFIDENCE ON THE ONSET TIMING.
* MEDIUM TO HIGH CONFIDENCE IN A PERIOD OF VERY HEAVY RAINFALL
WITH LOWER VIS AND CIGS THIS EVENING.
* MEDIUM CONFIDENCE IN WIND SPEED AND DIRECTION.
RODRIGUEZ
//OUTLOOK FOR ORD/MDW FOR 00Z FRIDAY-12Z WEDNESDAY...UPDATED 12Z...
THURSDAY NIGHT AND FRIDAY...VFR. WX NIL.
SAT THRU MON...VFR. CHC TSRA WITH LOCAL MVFR/IFR.
TUESDAY...VFR.
KJB
&&
.MARINE...
229 AM CDT
THE MAIN FORECAST CONCERNS ON THE LAKE IS THE THREAT FOR SEVERE
THUNDERSTORMS THIS AFTERNOON AND EVENING...ESPECIALLY ACROSS
SOUTHERN LAKE MICHIGAN...AND ALSO A PERIOD OF STRONG NORTHERLY WINDS
LATE TONIGHT AND ON THURSDAY.
DENSE FOG REMAINS ACROSS THE LAKE...ESPECIALLY ACROSS THE NORTHERN
HALF OF THE LAKE....AND I REALLY DONT SEE ANY IMPROVEMENT IN THESE
CONDITIONS UNTIL EITHER LATE THIS AFTERNOON OR THIS EVENING...WHEN
THE WINDS START TO BECOME NORTHERLY. THEREFORE...I HAVE EXTENDED THE
ADVISORY FOR THE OPEN WATERS THROUGH THIS AFTERNOON.
SEVERE THUNDERSTORMS LOOK TO BE A GOOD BET THIS AFTERNOON AND
EVENING...ESPECIALLY ACROSS SOUTHERN LAKE MICHGAN. THESE STORMS WILL
BE CAPABLE OF PRODUCING VERY LARGE HAIL AND STRONG DAMAGING WINDS
IN EXCESS OF 50 KT. THE THREAT OF SEVERE STORMS IS QUITE HIGH...SO
KEEP UP TO DATE ON THE LATEST WEATHER INFORMATION.
A SURFACE LOW IS EXPECTED TO PASS SOUTH OF THE LAKE TONIGHT. THIS
WILL SET UP SOME STRONG NORTHERLY WINDS UP TO 30 KT LATE TONIGHT AND
ON THURSDAY. THIS WILL LIKELY RESULT IN SMALL CRAFT ADVISORY
CONDITIONS FOR THE ILLINOIS AND INDIANA NEAR SHORE WATERS DURING THIS
TIME. CONDITIONS SHOULD BEGIN TO IMPROVE ON FRIDAY AS THE WINDS
ABATE AS A SURFACE RIDGE OF HIGH PRESSURE BUILDS ACROSS THE
LAKE.
KJB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...FLASH FLOOD WATCH...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-ILZ010-
ILZ011-ILZ012-ILZ013-ILZ014-ILZ020-ILZ022...4 PM WEDNESDAY
TO 4 AM THURSDAY.
IN...FLASH FLOOD WATCH...INZ001-INZ002...4 PM WEDNESDAY TO 4 AM
THURSDAY.
LM...DENSE FOG ADVISORY...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-
LMZ565-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-
LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 4 PM
WEDNESDAY.
SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742...1 AM THURSDAY TO 4
PM THURSDAY.
SMALL CRAFT ADVISORY...LMZ743-LMZ744-LMZ745...4 AM THURSDAY TO
11 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
113 PM CDT WED JUN 12 2013
.MESOSCALE DISCUSSION...
1042 AM CDT
...WIDESPREAD SEVERE WEATHER OUTBREAK ACROSS THE REGION EXPECTED
LATE THIS AFTERNOON AND EVENING INCLUDING TORNADIC POTENTIAL IN
NORTH CENTRAL IL LATE THIS AFTERNOON...
SEVERE WEATHER THREAT CONTINUES WITH OBSERVATIONAL TRENDS HINTING
MORE AT PRECISE EVOLUTION AND TIMING.
WHAT LEFTS OF OVERNIGHT DECAYING MCS IS MOVING FROM SOUTHEAST WI
OVER LAKE MI. VISIBLE SATELLITE AND REGIONAL RADAR MOSAIC
INDICATE SOME BRIEF SUPPRESSION BEHIND THIS WHILE THERE IS AN AXIS
EXTENDING SOUTHWARD ON RADAR OF LIKELY SOME MID-LEVEL CONVERGENCE.
THERE HAS NOT BEEN ANY DEVELOPMENT ALONG THIS THUS FAR BUT CANNOT
RULE OUT A FEW ELEVATED STORMS THROUGH 3 PM OR SO ACROSS FAR
NORTHERN AND NORTHEAST IL.
THE SURFACE LOW PRESSURE IS DEVELOPING NORTHEASTWARD INTO SOUTHWEST
AND CENTRAL IA AS OF 10 AM WITH A WARM FRONT EVOLVING EAST
NORTHEAST FROM THERE. THIS LOOKS TO BE FROM NEAR WATERLOO IA TO
SAVANNA IL AND THEN BECOMING MORE ILL-DEFINED EAST OF THERE INTO
THE CWA. DEW POINTS IN THE LOWER 70S ARE ADVECTING UP TO THIS
BOUNDARY WITH WINDS STRONGLY BACKED TO THE NORTH OF THIS. THERE
HAS BEEN GROWTH IN THE CU ACROSS IA NEAR THIS DEVELOPING FRONT.
AS THE MAIN VORT MAX AND MID-LEVEL SPEED MAX MOVE EAST FROM
EASTERN SD/NORTHEAST NE...DEVELOPMENT OF ROBUST CONVECTION IS
HIGHLY LIKELY BY MID AFTERNOON ACROSS NE IA/SW WI/NW IL. SUPERCELL
DEVELOPMENT WOULD BE A FAVORED MODE ALONG AND IMMEDIATELY NORTH OF
THE WARM FRONT. FURTHER NORTH AND NORTHEAST FROM THE TWIN CITIES
TO MILWAUKEE...ELEVATED CONVECTION MAY INCREASE. ALL OF THIS IS
SLIGHTLY FURTHER NORTH THAN EARLIER ANTICIPATED...BUT THE SEVERE
WEATHER THREAT HAS NOT DIMINISHED FOR OUR AREA...JUST FOCUSED MORE
SO IN THE LATE AFTERNOON AND EVE.
GIVEN THE ANTICIPATED EVOLUTION MENTIONED ABOVE WHICH HAS THE
SUPPORT OF THE RAP AND SEVERAL CONVECTIVE-ALLOWING MODELS...NORTH
CENTRAL IL WILL LIKELY BE UNDER THE GUN LATE THIS AFTERNOON. THIS
INCLUDES THE ROCKFORD AREA DURING RUSH HOUR AS STORMS EVOLVE
EASTWARD IN A FAVORED COMBINATION OF DISCRETE TO SMALL SCALE
CLUSTERS. TORNADIC POTENTIAL WILL CERTAINLY EXIST WITH THESE GIVEN
THE HELICITY RICH AIR NEAR THE BOUNDARY AND ANTICIPATED SURFACE-
BASED CAPE. CONVECTIVE TEMPERATURES FOR THIS ARE FORECAST TO BE
AROUND 80 DEGREES ON THE RAP. WHILE TEMPERATURE TRENDS HAVE BEEN
SLOW TO CLIMB ACROSS THE AREA THUS FAR...SOME THINNING OF THE
CLOUDS AND THE NORTHWARD PUSH OF THE WARM SECTOR SHOULD ALLOW THAT
TO OCCUR.
THE EVENING TIME PERIOD SHOULD SEE THE MOST COVERAGE OF SEVERE
CONVECTION IN THE FORECAST AREA AND WILL BE THE PRIME TIME FOR
CHICAGOLAND. THE LOW-LEVEL JET IS FORECAST TO INCREASE TO 40-50 KT
AND POINT INTO THE ONGOING CONVECTION. SOME SCATTERED CONVECTIVE
DEVELOPMENT...POTENTIALLY SEVERE AND SURFACE BASED...EAST AND
SOUTH OF THIS IS FAVORED DURING THE EVE. SUFFICIENT DEEP LAYER
SHEAR AND RICH LOW-LEVEL MOISTURE WILL OFFER AMPLE WIND THREAT
WITH THE ORGANIZED CONVECTIVE CLUSTERS. WITH THE SURFACE LOW
PROJECTED TO TRACK EAST NEAR THE I-88 CORRIDOR...THERE IS
INCREASING LIKELIHOOD THAT THE MAIN MCV/MCS WILL DEVELOP NEAR THIS
CORRIDOR AS WELL. A MAJORITY OF THE EXPLICIT GUIDANCE DOES
INDICATE THIS. VERY HEAVY RAINFALL AND AN ENHANCED WIND THREAT
WILL EXIST WITH THIS...WHICH WOULD LIKELY IMPACT CHICAGO IN THE
6-10 PM TIME FRAME.
MTF
&&
.DISCUSSION...
304 AM CDT
...MAJOR SEVERE WEATHER OUTBREAK LIKELY THIS AFTERNOON AND
EVENING...WITH HEAVY RAINFALL ALSO LIKELY...
EVERYTHING LINING UP FOR A SIGNIFICANT SEVERE WEATHER OUTBREAK
TODAY. SPC DAY 1 OUTLOOK HAS ENTIRE FORECAST AREA IN MODERATE RISK
OF SEVERE WITH SIGNIFICANT WIND...HAIL...AND TORNADO THREAT. AT THE
SURFACE...LOW PRESSURE OVER THE PLAINS WITH A WEAK WARM FRONT
EXTENDING EAST INTO NORTHERN IL EARLY THIS MORNING. THE LOW WILL
MOVE EAST ALONG THE IA/MO BOARDER TODAY...AND ACROSS NORTHERN IL
THIS EVENING. VERY MOIST LOW LEVEL AIR WITH SURFACE DEW POINTS IN
THE MID AND UPPER 60S IN PLACE. MAY SEE DEWPOINTS POOL IN THE LOWER
70S SOUTH OF WARM FRONT THIS AFTERNOON. THE BOUNDARY WILL INTENSIFY
AS SOUTHWEST LOW LEVEL FLOW INCREASES SOUTH OF THE FRONT AND SURFACE
WINDS BACK TO SE OR E NORTH OF THE BOUNDARY. THIS WILL PULL MODIFIED
MARINE AIR BACK ACROSS FAR NORTHERN IL. HAVE SOME CONCERNS ABOUT HOW
FAR NORTH THE WARM FRONT WILL TRAVEL. SPC DISCUSSION SUGGESTING THE
BOUNDARY WILL MOVE INTO SOUTHERN WI BUT WITH MODELS TAKING LOW
ACROSS I-80 CORRIDOR AND COOLING INFLUENCE OF LAKE
MICHIGAN...THINKING FRONT WONT GET MUCH FARTHER NORTH THAN A
DIXON-GARY LINE. THIS MAY LIMIT NORTHERN EXTEND OF SIGNIFICANT
SEVERE THREAT. THE BOUNDARY WILL ALSO RESULT IN A CHALLENGING
TEMPERATURE FORECAST...WITH TEMPS REACHING LOWER 90S FAR SOUTHERN
PART OF FORECAST AREA...WHILE AREAS ALONG THE NORTH SHORE WILL
LIKELY BE 20 DEGREES COOLER. IT APPEARS THAT MOST OF THE OVERNIGHT
EARLY MORNING CONVECTION WILL AFFECT WI...BUT KEEPING AN EYE ON
MCS OVER WESTERN IA WHICH COULD MOVE INTO NORTHERN IL THIS
MORNING. EARLIER CONVECTION OVER EASTERN IA WEAKENED AS IT MOVED
EAST AND THINK THIS MCS MAY DO THE SAME. CLOUD DEBRIS SHOULD
REMAIN NORTH ALLOWING AREAS SOUTH OF THE WARM FRONT TO HEAT UP
SIGNIFICANTLY...INTO THE UPPER 80S TO LOWER 90S. THIS COULD RESULT
IN SURFACE BASED CAPE OF 3000+ THIS AFTERNOON. FAIRLY VIGOROUS
SHORT WAVE MOVING INTO WESTERN SD/NE EARLY THIS MORNING WILL BE
MOVING ACROSS NORTHERN IL THIS EVENING. MODEL SOUNDINGS SHOW
FAIRLY STOUT CAP EARLY IN THE DAY ERODES THIS AFTERNOON WITH
APPROACHING SHORT WAVE. LOOKING AT 0-6KM BULK SHEAR 50-60 KTS BY
THIS EVENING. WITH INCREASING LOW LEVEL FLOW THIS AFTERNOON AND
BACKING SURFACE WINDS ALONG THE BOUNDARY...SHOULD PRODUCE AN
ENVIRONMENT FAVORABLE FOR DAMAGING WINDS...LARGE HAIL...AND
TORNADOES. SOME OF THE SHORT RANGE HI RES GUIDANCE IS SUGGESTING
DISCRETE STORMS INITIALLY THIS AFTERNOON. EXPECT THE TORNADO
THREAT TO BE MAINLY DURING THE AFTERNOON. STORMS WILL LIKELY
CONGEAL INTO AN MCS AND BECOME MORE OF A HIGH WIND WITH EMBEDDED
QLCS TORNADO THREAT IN THE EVENING. THE OTHER CONCERN IS WITH
PWATS AROUND 2 INCHES...AND SURFACE DEW POINTS NEAR
70...THUNDERSTORMS WILL BE CAPABLE OF VERY HEAVY RAINFALL AND AS
MCS DEVELOPS...FLOODING WILL ALSO BE A CONCERN. MODEL CONSENSUS IS
TO PLACE HEAVIEST QPF NORTH OF THE BOUNDARY OVER THE RFD AND
CHICAGO AREAS. SEE HYDRO SECTION OF THE AFD BELOW.
AFTER THE PASSAGE OF THIS SYSTEM...CENTRAL US RIDGE SHARPENS
BRINGING MUCH DRIER AND COOLER NORTHWEST FLOW FOR THU AND FRI.
EVENTUALLY PACNW UPPER LOW MOVES EAST ACROSS THE CANADIAN PRAIRIES
WHICH WILL PUSH THE RIDGE AXIS EASTWARD AND FLATTEN IT OUT. THUS A
FEW MORE ROUNDS OF THUNDERSTORMS ARE LIKELY TO RETURN SATURDAY AND
SUNDAY AND POSSIBLY INTO MONDAY BEFORE UPPER LOW OPENS INTO A
POTENT SHORT WAVE AND DROPS SOUTHEAST THROUGH THE GREAT LAKES.
ALLSOPP
&&
.HYDROLOGY...
HAVE ISSUED A FLASH FLOOD WATCH FOR AREAS GENERALLY NORTH OF A
DIXON TO VALPARAISO LINE. THERE IS THE POTENTIAL FOR WIDESPREAD HEAVY
RAINFALL OF 2 TO 3 INCHES ACROSS THIS AREA...WITH LOCALLY UP TO 5
INCHES. THE AXIS OF HEAVIEST RAIN WILL BE OVER THE HIGHLY
URBANIZED ROCKFORD AND CHICAGO METRO AREAS. ALSO CONCERNED FOR THE
POTENTIAL OF VERY HIGH RAINFALL RATES IN SOME OF THE HEAVIER DOWNPOURS.
ALLSOPP
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 18Z...
* STRONG/SEVERE THUNDERSTORM POTENTIAL LATE THIS AFTERNOON INTO
THIS EVENING THAT COULD HAVE SIGNIFICANT IMPACTS ON THE
TERMINALS...SHOWERS/THUNDERSTORMS INCREASING AFTER 20Z.
* POTENTIAL FOR VERY HEAVY RAIN THIS EVENING...WITH IFR/LIFR VIS
AND IFR CIGS POSSIBLE FOR A PERIOD.
* SOUTHERLY WINDS WITH GUSTS IN THE MID/UPPER TEENS POSSIBLE
BEFORE WINDS ARE EXPECTED TO GO BACK TO THE EAST NORTHEAST BY
MID AFTERNOON...THEN INCREASING OUT OF THE NORTH/NORTHEAST THIS
EVENING.
RODRIGUEZ
//DISCUSSION...UPDATED 18Z...
CONTINUE TO MONITOR THE POTENTIAL FOR SIGNIFICANT WEATHER TO AFFECT
THE TERMINALS LATER THIS AFTERNOON THROUGH THIS EVENING. ALTHOUGH
AT THIS TIME...RATHER QUIET ACROSS THE TERMINALS WITH VFR
CONDITIONS IN PLACE. WITH THE TRACK OF THE LOW THIS
MORNING...WINDS HAVE ACTUALLY BEEN ORIENTED MORE OUT OF A
SOUTHERLY DIRECTION TODAY. THIS WILL CONTINUE TO OCCUR WITH SOME
SPORADIC GUSTS BUT WITH A SHIFT BACK TO THE EAST NORTHEAST BY MID
AFTERNOON...WITH WINDS REMAINING MORE NORTHERLY THROUGH THE END OF
THE FORECAST PERIOD. DO EXPECT AN INCREASE IN ACTIVITY BY MID
AFTERNOON WITH SCATTERED SHOWERS/THUNDERSTORMS EXPECTED TO DEVELOP
ACROSS THE TERMINALS. THIS INITIAL ONSET IS EXPECTED TO ONLY HAVE
LIMITED IMPACTS ON THE TERMINALS BUT WITH THIS TO QUICKLY CHANGE
AS WE GO INTO THE LATE AFTERNOON. THUNDERSTORM DEVELOPMENT WILL
INCREASE WITH COVERAGE/INTENSITY OF THESE STORMS ALSO INCREASING
AS THEY SHIFT EAST ACROSS THE TERMINALS. NOT ONLY WILL LOWER
VIS/CEILINGS IN HEAVY RAIN WILL BE POSSIBLE...BUT STRONG/SHIFTING
WINDS ARE DEFINITELY POSSIBLE WITH THE STRONGEST THUNDERSTORMS
LATER THIS AFTERNOON. THIS WILL HAVE TO BE ADDRESSED WITH LATER
AMENDMENTS ONCE THUNDERSTORM INITIATION OCCURS AND THE FULL
THREAT OF CHANGING WEATHER FOR THE TERMINALS IS KNOWN.
SHOWERS/ISOLATED THUNDER SHOULD DIMINISH LATE THIS EVENING THROUGH
OVERNIGHT...WITH DRIER CONDITIONS EXPECTED EARLY THURSDAY MORNING
AS WELL AS CEILINGS IMPROVING.
RODRIGUEZ
//ORD AND MDW CONFIDENCE...UPDATED 18Z...
* MEDIUM TO HIGH CONFIDENCE IN CHANCES FOR THUNDERSTORMS LATER
TODAY AND TONIGHT...BUT MEDIUM CONFIDENCE ON THE ONSET TIMING.
* MEDIUM TO HIGH CONFIDENCE IN A PERIOD OF VERY HEAVY RAINFALL
WITH LOWER VIS AND CIGS THIS EVENING.
* MEDIUM CONFIDENCE IN WIND SPEED AND DIRECTION.
RODRIGUEZ
//OUTLOOK FOR ORD/MDW FOR 00Z FRIDAY-12Z WEDNESDAY...UPDATED 12Z...
THURSDAY NIGHT AND FRIDAY...VFR. WX NIL.
SAT THRU MON...VFR. CHC TSRA WITH LOCAL MVFR/IFR.
TUESDAY...VFR.
KJB
&&
.MARINE...
229 AM CDT
THE MAIN FORECAST CONCERNS ON THE LAKE IS THE THREAT FOR SEVERE
THUNDERSTORMS THIS AFTERNOON AND EVENING...ESPECIALLY ACROSS
SOUTHERN LAKE MICHIGAN...AND ALSO A PERIOD OF STRONG NORTHERLY WINDS
LATE TONIGHT AND ON THURSDAY.
DENSE FOG REMAINS ACROSS THE LAKE...ESPECIALLY ACROSS THE NORTHERN
HALF OF THE LAKE....AND I REALLY DONT SEE ANY IMPROVEMENT IN THESE
CONDITIONS UNTIL EITHER LATE THIS AFTERNOON OR THIS EVENING...WHEN
THE WINDS START TO BECOME NORTHERLY. THEREFORE...I HAVE EXTENDED THE
ADVISORY FOR THE OPEN WATERS THROUGH THIS AFTERNOON.
SEVERE THUNDERSTORMS LOOK TO BE A GOOD BET THIS AFTERNOON AND
EVENING...ESPECIALLY ACROSS SOUTHERN LAKE MICHGAN. THESE STORMS WILL
BE CAPABLE OF PRODUCING VERY LARGE HAIL AND STRONG DAMAGING WINDS
IN EXCESS OF 50 KT. THE THREAT OF SEVERE STORMS IS QUITE HIGH...SO
KEEP UP TO DATE ON THE LATEST WEATHER INFORMATION.
A SURFACE LOW IS EXPECTED TO PASS SOUTH OF THE LAKE TONIGHT. THIS
WILL SET UP SOME STRONG NORTHERLY WINDS UP TO 30 KT LATE TONIGHT AND
ON THURSDAY. THIS WILL LIKELY RESULT IN SMALL CRAFT ADVISORY
CONDITIONS FOR THE ILLINOIS AND INDIANA NEAR SHORE WATERS DURING THIS
TIME. CONDITIONS SHOULD BEGIN TO IMPROVE ON FRIDAY AS THE WINDS
ABATE AS A SURFACE RIDGE OF HIGH PRESSURE BUILDS ACROSS THE
LAKE.
KJB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...FLASH FLOOD WATCH...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-ILZ010-
ILZ011-ILZ012-ILZ013-ILZ014-ILZ020-ILZ022...4 PM WEDNESDAY
TO 4 AM THURSDAY.
IN...FLASH FLOOD WATCH...INZ001-INZ002...4 PM WEDNESDAY TO 4 AM
THURSDAY.
LM...DENSE FOG ADVISORY...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-
LMZ565-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-
LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 4 PM
WEDNESDAY.
SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742...1 AM THURSDAY TO 4
PM THURSDAY.
SMALL CRAFT ADVISORY...LMZ743-LMZ744-LMZ745...4 AM THURSDAY TO
11 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
1121 AM CDT WED JUN 12 2013
.MESOSCALE DISCUSSION...
1042 AM CDT
...WIDESPREAD SEVERE WEATHER OUTBREAK ACROSS THE REGION EXPECTED
LATE THIS AFTERNOON AND EVENING INCLUDING TORNADIC POTENTIAL IN
NORTH CENTRAL IL LATE THIS AFTERNOON...
SEVERE WEATHER THREAT CONTINUES WITH OBSERVATIONAL TRENDS HINTING
MORE AT PRECISE EVOLUTION AND TIMING.
WHAT LEFTS OF OVERNIGHT DECAYING MCS IS MOVING FROM SOUTHEAST WI
OVER LAKE MI. VISIBLE SATELLITE AND REGIONAL RADAR MOSAIC
INDICATE SOME BRIEF SUPPRESSION BEHIND THIS WHILE THERE IS AN AXIS
EXTENDING SOUTHWARD ON RADAR OF LIKELY SOME MID-LEVEL CONVERGENCE.
THERE HAS NOT BEEN ANY DEVELOPMENT ALONG THIS THUS FAR BUT CANNOT
RULE OUT A FEW ELEVATED STORMS THROUGH 3 PM OR SO ACROSS FAR
NORTHERN AND NORTHEAST IL.
THE SURFACE LOW PRESSURE IS DEVELOPING NORTHEASTWARD INTO SOUTHWEST
AND CENTRAL IA AS OF 10 AM WITH A WARM FRONT EVOLVING EAST
NORTHEAST FROM THERE. THIS LOOKS TO BE FROM NEAR WATERLOO IA TO
SAVANNA IL AND THEN BECOMING MORE ILL-DEFINED EAST OF THERE INTO
THE CWA. DEW POINTS IN THE LOWER 70S ARE ADVECTING UP TO THIS
BOUNDARY WITH WINDS STRONGLY BACKED TO THE NORTH OF THIS. THERE
HAS BEEN GROWTH IN THE CU ACROSS IA NEAR THIS DEVELOPING FRONT.
AS THE MAIN VORT MAX AND MID-LEVEL SPEED MAX MOVE EAST FROM
EASTERN SD/NORTHEAST NE...DEVELOPMENT OF ROBUST CONVECTION IS
HIGHLY LIKELY BY MID AFTERNOON ACROSS NE IA/SW WI/NW IL. SUPERCELL
DEVELOPMENT WOULD BE A FAVORED MODE ALONG AND IMMEDIATELY NORTH OF
THE WARM FRONT. FURTHER NORTH AND NORTHEAST FROM THE TWIN CITIES
TO MILWAUKEE...ELEVATED CONVECTION MAY INCREASE. ALL OF THIS IS
SLIGHTLY FURTHER NORTH THAN EARLIER ANTICIPATED...BUT THE SEVERE
WEATHER THREAT HAS NOT DIMINISHED FOR OUR AREA...JUST FOCUSED MORE
SO IN THE LATE AFTERNOON AND EVE.
GIVEN THE ANTICIPATED EVOLUTION MENTIONED ABOVE WHICH HAS THE
SUPPORT OF THE RAP AND SEVERAL CONVECTIVE-ALLOWING MODELS...NORTH
CENTRAL IL WILL LIKELY BE UNDER THE GUN LATE THIS AFTERNOON. THIS
INCLUDES THE ROCKFORD AREA DURING RUSH HOUR AS STORMS EVOLVE
EASTWARD IN A FAVORED COMBINATION OF DISCRETE TO SMALL SCALE
CLUSTERS. TORNADIC POTENTIAL WILL CERTAINLY EXIST WITH THESE GIVEN
THE HELICITY RICH AIR NEAR THE BOUNDARY AND ANTICIPATED SURFACE-
BASED CAPE. CONVECTIVE TEMPERATURES FOR THIS ARE FORECAST TO BE
AROUND 80 DEGREES ON THE RAP. WHILE TEMPERATURE TRENDS HAVE BEEN
SLOW TO CLIMB ACROSS THE AREA THUS FAR...SOME THINNING OF THE
CLOUDS AND THE NORTHWARD PUSH OF THE WARM SECTOR SHOULD ALLOW THAT
TO OCCUR.
THE EVENING TIME PERIOD SHOULD SEE THE MOST COVERAGE OF SEVERE
CONVECTION IN THE FORECAST AREA AND WILL BE THE PRIME TIME FOR
CHICAGOLAND. THE LOW-LEVEL JET IS FORECAST TO INCREASE TO 40-50 KT
AND POINT INTO THE ONGOING CONVECTION. SOME SCATTERED CONVECTIVE
DEVELOPMENT...POTENTIALLY SEVERE AND SURFACE BASED...EAST AND
SOUTH OF THIS IS FAVORED DURING THE EVE. SUFFICIENT DEEP LAYER
SHEAR AND RICH LOW-LEVEL MOISTURE WILL OFFER AMPLE WIND THREAT
WITH THE ORGANIZED CONVECTIVE CLUSTERS. WITH THE SURFACE LOW
PROJECTED TO TRACK EAST NEAR THE I-88 CORRIDOR...THERE IS
INCREASING LIKELIHOOD THAT THE MAIN MCV/MCS WILL DEVELOP NEAR THIS
CORRIDOR AS WELL. A MAJORITY OF THE EXPLICIT GUIDANCE DOES
INDICATE THIS. VERY HEAVY RAINFALL AND AN ENHANCED WIND THREAT
WILL EXIST WITH THIS...WHICH WOULD LIKELY IMPACT CHICAGO IN THE
6-10 PM TIME FRAME.
MTF
&&
.DISCUSSION...
304 AM CDT
...MAJOR SEVERE WEATHER OUTBREAK LIKELY THIS AFTERNOON AND
EVENING...WITH HEAVY RAINFALL ALSO LIKELY...
EVERYTHING LINING UP FOR A SIGNIFICANT SEVERE WEATHER OUTBREAK
TODAY. SPC DAY 1 OUTLOOK HAS ENTIRE FORECAST AREA IN MODERATE RISK
OF SEVERE WITH SIGNIFICANT WIND...HAIL...AND TORNADO THREAT. AT THE
SURFACE...LOW PRESSURE OVER THE PLAINS WITH A WEAK WARM FRONT
EXTENDING EAST INTO NORTHERN IL EARLY THIS MORNING. THE LOW WILL
MOVE EAST ALONG THE IA/MO BOARDER TODAY...AND ACROSS NORTHERN IL
THIS EVENING. VERY MOIST LOW LEVEL AIR WITH SURFACE DEW POINTS IN
THE MID AND UPPER 60S IN PLACE. MAY SEE DEWPOINTS POOL IN THE LOWER
70S SOUTH OF WARM FRONT THIS AFTERNOON. THE BOUNDARY WILL INTENSIFY
AS SOUTHWEST LOW LEVEL FLOW INCREASES SOUTH OF THE FRONT AND SURFACE
WINDS BACK TO SE OR E NORTH OF THE BOUNDARY. THIS WILL PULL MODIFIED
MARINE AIR BACK ACROSS FAR NORTHERN IL. HAVE SOME CONCERNS ABOUT HOW
FAR NORTH THE WARM FRONT WILL TRAVEL. SPC DISCUSSION SUGGESTING THE
BOUNDARY WILL MOVE INTO SOUTHERN WI BUT WITH MODELS TAKING LOW
ACROSS I-80 CORRIDOR AND COOLING INFLUENCE OF LAKE
MICHIGAN...THINKING FRONT WONT GET MUCH FARTHER NORTH THAN A
DIXON-GARY LINE. THIS MAY LIMIT NORTHERN EXTEND OF SIGNIFICANT
SEVERE THREAT. THE BOUNDARY WILL ALSO RESULT IN A CHALLENGING
TEMPERATURE FORECAST...WITH TEMPS REACHING LOWER 90S FAR SOUTHERN
PART OF FORECAST AREA...WHILE AREAS ALONG THE NORTH SHORE WILL
LIKELY BE 20 DEGREES COOLER. IT APPEARS THAT MOST OF THE OVERNIGHT
EARLY MORNING CONVECTION WILL AFFECT WI...BUT KEEPING AN EYE ON
MCS OVER WESTERN IA WHICH COULD MOVE INTO NORTHERN IL THIS
MORNING. EARLIER CONVECTION OVER EASTERN IA WEAKENED AS IT MOVED
EAST AND THINK THIS MCS MAY DO THE SAME. CLOUD DEBRIS SHOULD
REMAIN NORTH ALLOWING AREAS SOUTH OF THE WARM FRONT TO HEAT UP
SIGNIFICANTLY...INTO THE UPPER 80S TO LOWER 90S. THIS COULD RESULT
IN SURFACE BASED CAPE OF 3000+ THIS AFTERNOON. FAIRLY VIGOROUS
SHORT WAVE MOVING INTO WESTERN SD/NE EARLY THIS MORNING WILL BE
MOVING ACROSS NORTHERN IL THIS EVENING. MODEL SOUNDINGS SHOW
FAIRLY STOUT CAP EARLY IN THE DAY ERODES THIS AFTERNOON WITH
APPROACHING SHORT WAVE. LOOKING AT 0-6KM BULK SHEAR 50-60 KTS BY
THIS EVENING. WITH INCREASING LOW LEVEL FLOW THIS AFTERNOON AND
BACKING SURFACE WINDS ALONG THE BOUNDARY...SHOULD PRODUCE AN
ENVIRONMENT FAVORABLE FOR DAMAGING WINDS...LARGE HAIL...AND
TORNADOES. SOME OF THE SHORT RANGE HI RES GUIDANCE IS SUGGESTING
DISCRETE STORMS INITIALLY THIS AFTERNOON. EXPECT THE TORNADO
THREAT TO BE MAINLY DURING THE AFTERNOON. STORMS WILL LIKELY
CONGEAL INTO AN MCS AND BECOME MORE OF A HIGH WIND WITH EMBEDDED
QLCS TORNADO THREAT IN THE EVENING. THE OTHER CONCERN IS WITH
PWATS AROUND 2 INCHES...AND SURFACE DEW POINTS NEAR
70...THUNDERSTORMS WILL BE CAPABLE OF VERY HEAVY RAINFALL AND AS
MCS DEVELOPS...FLOODING WILL ALSO BE A CONCERN. MODEL CONSENSUS IS
TO PLACE HEAVIEST QPF NORTH OF THE BOUNDARY OVER THE RFD AND
CHICAGO AREAS. SEE HYDRO SECTION OF THE AFD BELOW.
AFTER THE PASSAGE OF THIS SYSTEM...CENTRAL US RIDGE SHARPENS
BRINGING MUCH DRIER AND COOLER NORTHWEST FLOW FOR THU AND FRI.
EVENTUALLY PACNW UPPER LOW MOVES EAST ACROSS THE CANADIAN PRAIRIES
WHICH WILL PUSH THE RIDGE AXIS EASTWARD AND FLATTEN IT OUT. THUS A
FEW MORE ROUNDS OF THUNDERSTORMS ARE LIKELY TO RETURN SATURDAY AND
SUNDAY AND POSSIBLY INTO MONDAY BEFORE UPPER LOW OPENS INTO A
POTENT SHORT WAVE AND DROPS SOUTHEAST THROUGH THE GREAT LAKES.
ALLSOPP
&&
.HYDROLOGY...
HAVE ISSUED A FLASH FLOOD WATCH FOR AREAS GENERALLY NORTH OF A
DIXON TO VALPARAISO LINE. THERE IS THE POTENTIAL FOR WIDESPREAD HEAVY
RAINFALL OF 2 TO 3 INCHES ACROSS THIS AREA...WITH LOCALLY UP TO 5
INCHES. THE AXIS OF HEAVIEST RAIN WILL BE OVER THE HIGHLY
URBANIZED ROCKFORD AND CHICAGO METRO AREAS. ALSO CONCERNED FOR THE
POTENTIAL OF VERY HIGH RAINFALL RATES IN SOME OF THE HEAVIER DOWNPOURS.
ALLSOPP
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 16Z...
* STRONG TO SEVERE THUNDERSTORM POTENTIAL LATER TODAY AND INTO
THIS EVENING...WITH SHOWERS/THUNDERSTORMS INCREASING AFTER
19-20Z.
* POTENTIAL FOR VERY HEAVY RAIN THIS EVENING...WITH IFR VIS AND
CIGS POSSIBLE FOR A PERIOD.
* SOUTH TO SOUTHWEST WIND NOW LIKELY WITH GUSTS TO AROUND 19KT
THROUGH EARLY AFTERNOON...BEFORE GOING BACK TO THE EAST
NORTHEAST BY MID AFTERNOON.
RODRIGUEZ
//DISCUSSION...UPDATED 12Z...
FORECAST CHALLENGES THIS MORNING CONTINUE TO CENTER AROUND TIMING
THE ONSET OF THUNDERSTORM ACTIVITY TODAY.
A COMPLEX OF THUNDERSTORMS ACROSS IOWA DEVELOPED EARLIER THIS
MORNING ALONG THE NOSE OF A LOW LEVEL JET. THIS ACTIVITY HAS BEEN
WEAKENING OVER THE PAST COUPLE HOURS. HOWEVER...THIS ACTIVITY HAS
ENHANCED A MID LEVEL DISTURBANCE (MCV) ACROSS NORTHERN IOWA. THIS
LEAD DISTURBANCE COULD ACT TO SPARK OFF SOME SCT CONVECTION ACROSS
FAR NORTHERN ILLINOIS LATER THIS MORNING. CONFIDENCE IS LOW WITH
THE POTENTIAL FOR THIS EARLIER ACTIVITY. HOWEVER...I FELT THAT A
VCSH MENTION WAS JUSTIFIED AFTER 15 UTC.
OTHERWISE...THE ONLY OTHER CHANCES TO NEW TAFS WAS TO ADD A VCTS
AFTER 20 UTC...A COUPLE HOURS EARLIER THAN THE PREVIOUS 22 UTC
TIMING. THIS WAS MAINLY DUE TO THE POTENTIAL FOR ACTIVITY TO FIRE
ALONG THE SURFACE FRONT. IT APPEARS THAT AS THE SURFACE FLOW
INCREASES OFF THE LAKE TO THE NORTH OF THE WARM FRONTAL BOUNDARY
THAT LOW LEVEL CONVERGENCE WILL STRENGTHEN...AND THIS COULD BE
ENOUGH TO FIRE OFF ACTIVITY BY EARLY TO MID AFTERNOON.
BY FAR THE BEST CHANCES FOR THUNDERSTORMS WILL BE LATER THIS
AFTERNOON AND EVENING. THIS IS THE TIME WHEN THE BEST DYNAMICS
ASSOCIATED WITH THE MAIN DISTURBANCE SHOULD OVERSPREAD THE AREA.
SEVERE THUNDERSTORMS WITH LARGE HAIL...DAMAGING WINDS...AND EVEN
TORNADO`S ARE STILL POSSIBLE. VERY HEAVY RAINFALL WILL ALSO LIKELY
ACCOMPANY THESE STORMS...ESPECIALLY THIS EVENING. THIS COULD LEAD
TO LOCALIZED FLOODING AND REDUCTIONS IN THE VIS DOWN UNDER 2
MILES. IT APPEARS THAT THIS ACTIVITY COULD LAST FOR A 3 TO 6 HOUR
WINDOW INTO THIS EVENING BEFORE CONDITIONS BEGIN TO IMPROVE
OVERNIGHT.
KJB
//ORD AND MDW CONFIDENCE...UPDATED 16Z...
* MEDIUM TO HIGH CONFIDENCE IN CHANCES FOR THUNDERSTORMS LATER
TODAY AND TONIGHT...BUT LOW MEDIUM CONFIDENCE ON THE ONSET
TIMING.
* MEDIUM CONFIDENCE IN A PERIOD OF VERY HEAVY RAINFALL WITH
LOWER VIS AND CIGS THIS EVENING.
* MEDIUM CONFIDENCE IN WIND SPEED AND DIRECTION.
RODRIGUEZ
//OUTLOOK FOR ORD/MDW FOR 00Z FRIDAY-12Z WEDNESDAY...UPDATED 12Z...
THURSDAY NIGHT AND FRIDAY...VFR. WX NIL.
SAT THRU MON...VFR. CHC TSRA WITH LOCAL MVFR/IFR.
TUESDAY...VFR.
KJB
&&
.MARINE...
229 AM CDT
THE MAIN FORECAST CONCERNS ON THE LAKE IS THE THREAT FOR SEVERE
THUNDERSTORMS THIS AFTERNOON AND EVENING...ESPECIALLY ACROSS
SOUTHERN LAKE MICHIGAN...AND ALSO A PERIOD OF STRONG NORTHERLY WINDS
LATE TONIGHT AND ON THURSDAY.
DENSE FOG REMAINS ACROSS THE LAKE...ESPECIALLY ACROSS THE NORTHERN
HALF OF THE LAKE....AND I REALLY DONT SEE ANY IMPROVEMENT IN THESE
CONDITIONS UNTIL EITHER LATE THIS AFTERNOON OR THIS EVENING...WHEN
THE WINDS START TO BECOME NORTHERLY. THEREFORE...I HAVE EXTENDED THE
ADVISORY FOR THE OPEN WATERS THROUGH THIS AFTERNOON.
SEVERE THUNDERSTORMS LOOK TO BE A GOOD BET THIS AFTERNOON AND
EVENING...ESPECIALLY ACROSS SOUTHERN LAKE MICHGAN. THESE STORMS WILL
BE CAPABLE OF PRODUCING VERY LARGE HAIL AND STRONG DAMAGING WINDS
IN EXCESS OF 50 KT. THE THREAT OF SEVERE STORMS IS QUITE HIGH...SO
KEEP UP TO DATE ON THE LATEST WEATHER INFORMATION.
A SURFACE LOW IS EXPECTED TO PASS SOUTH OF THE LAKE TONIGHT. THIS
WILL SET UP SOME STRONG NORTHERLY WINDS UP TO 30 KT LATE TONIGHT AND
ON THURSDAY. THIS WILL LIKELY RESULT IN SMALL CRAFT ADVISORY
CONDITIONS FOR THE ILLINOIS AND INDIANA NEAR SHORE WATERS DURING THIS
TIME. CONDITIONS SHOULD BEGIN TO IMPROVE ON FRIDAY AS THE WINDS
ABATE AS A SURFACE RIDGE OF HIGH PRESSURE BUILDS ACROSS THE
LAKE.
KJB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...FLASH FLOOD WATCH...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-ILZ010-
ILZ011-ILZ012-ILZ013-ILZ014-ILZ020-ILZ022...4 PM WEDNESDAY
TO 4 AM THURSDAY.
IN...FLASH FLOOD WATCH...INZ001-INZ002...4 PM WEDNESDAY TO 4 AM
THURSDAY.
LM...DENSE FOG ADVISORY...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-
LMZ565-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-
LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 4 PM
WEDNESDAY.
SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742...1 AM THURSDAY TO 4
PM THURSDAY.
SMALL CRAFT ADVISORY...LMZ743-LMZ744-LMZ745...4 AM THURSDAY TO
11 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
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AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
633 PM EDT WED JUN 12 2013
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 308 PM EDT WED JUN 12 2013
STRONG TO SEVERE STORMS WILL OCCUR TONIGHT AHEAD OF A COLD FRONT.
RAIN WILL LINGER INTO THURSDAY MORNING...THEN DRY CONDITIONS CAN BE
EXPECTED UNTIL SATURDAY AFTERNOON. A COUPLE OF WEATHER SYSTEMS WILL
KEEP CHANCES FOR RAIN AROUND FROM SATURDAY AFTERNOON INTO NEXT
TUESDAY. TEMPERATURES WILL BE COOLER THAN NORMAL ON THURSDAY BUT
RETURN TO NEAR AVERAGE AND REMAIN THERE FROM THE WEEKEND ON.
&&
.NEAR TERM /LATE THIS AFTERNOON AND TONIGHT/...
ISSUED AT 308 PM EDT WED JUN 12 2013
DECENT CAP SHOULD KEEP CONVECTION AT BAY FOR THE NEXT FEW
HOURS...BUT THEN SCATTERED CONVECTION COULD BREAK THROUGH AS COOLER
AIR FILTERS IN ALOFT. PLENTY OF INSTABILITY AROUND...SO ANY
CONVECTION THAT DOES DEVELOP COULD BECOME SEVERE.
ADDITIONAL THUNDERSTORMS WILL DEVELOP AND MOVE INTO THE AREA THIS
EVENING AND OVERNIGHT AS A COLD FRONT AND UPPER TROUGH MOVES IN. IN
ADDITION THE LEFT EXIT REGION OF AN UPPER JET WILL PROVIDE
ADDITIONAL LIFT.
STILL A HIGH RISK OF SEVERE WEATHER FOR THE EXTREME NORTHERN
FORECAST AREA WITH A MODERATE RISK ELSEWHERE. HIGH INSTABILITY AND
DECENT SHEAR WILL HELP THE POTENTIAL FOR ANY STORM THAT DOES DEVELOP
TO BECOME SEVERE.
THERE IS A CONCERN OVER A POTENTIAL SEVERE SQUALL LINE MOVING ACROSS
NORTHERN INDIANA THIS EVENING INTO EARLY OVERNIGHT. VERY STRONG
WINDS ARE POSSIBLE WITH THIS LINE. THE QUESTION IS HOW FAR SOUTH
WILL IT DEVELOP/MOVE. HRRR MODEL HAS BEEN KEEPING THIS LINE MOSTLY
NORTH OF THE AREA WITH A WEAK TAIL-END OF THE LINE MOVING ACROSS
CENTRAL INDIANA. OTHER MODELS SUCH AS NCEP WRF-NMM SHOW A MUCH
LONGER LINE OF STORMS THAT WILL MOVE ACROSS MOST OF THE AREA.
THUS WHILE SOME SEVERE WEATHER IS LIKELY SOMEWHERE ACROSS THE
NORTHERN FORECAST AREA TONIGHT...UNCERTAINTY IS HIGH ABOUT COVERAGE
OF STORMS ACROSS THE SOUTHERN FORECAST AREA. GIVEN THE FORCING
LISTED EARLIER HAVE DECIDED TO GO AT LEAST LOW END LIKELY POPS MOST
AREAS...WITH CATEGORICAL POPS ACROSS THE FAR NORTH. WILL CONTINUE TO
MENTION SEVERE AND HEAVY RAIN IN PRODUCTS.
FOR TEMPERATURES WENT WITH A BLEND.
&&
.SHORT TERM /THURSDAY THROUGH SATURDAY/...
ISSUED AT 308 PM EDT WED JUN 12 2013
FOCUS IS ON CHANCES FOR RAIN THROUGH THE PERIOD. MODELS ARE CLOSE
ENOUGH THAT A BLEND CAN BE USED.
SOME LINGERING FORCING WILL CONTINUE ACROSS MAINLY THE SOUTHERN AND
EASTERN FORECAST AREA ON THURSDAY MORNING AS SYSTEM EXITS THE AREA.
WENT LIKELY POPS EXTREME EAST TO LOW CHANCE POPS WEST. ENDED CHANCES
FOR RAIN BY AFTERNOON AS THE SYSTEM PULLS EAST.
HIGH PRESSURE WILL THEN PROVIDE DRY CONDITIONS THURSDAY NIGHT INTO
SATURDAY MORNING.
UPPER WAVES RIDING AROUND AN UPPER RIDGE COULD TRIGGER SOME
CONVECTION ACROSS THE AREA SATURDAY AFTERNOON. UNCERTAINTY REMAINS
HIGH IN THE TIMING AND STRENGTH OF THESE WAVES. THEREFORE ONLY WENT
CHANCE POPS SATURDAY AFTERNOON...MAINLY ACROSS THE NORTHWEST
FORECAST AREA CLOSER TO THE FORCING.
FOR TEMPERATURES THROUGH THE PERIOD WENT WITH A BLEND MOST PERIODS.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
ISSUED AT 227 PM EDT WED JUN 12 2013
MODELS AND WEATHER PREDICTION CENTER SUGGEST A COLD FRONT WILL DROP
SOUTHEAST ACROSS CENTRAL INDIANA ON MONDAY FOLLOWED BY AN UPPER WAVE
ON TUESDAY. MOISTURE STREAMING NORTHEAST OFF THE GULF AHEAD OF THE
FRONT SHOULD ALLOW FOR SCATTERED TO NUMEROUS THUNDERSTORMS PRIOR TO
THE FRONTAL PASSAGE WITH LOWER CHANCES AHEAD OF THE UPPER FEATURE.
REGIONAL INITIALIZATION TEMPERATURES NEAR NORMAL IN THE LOWER TO MID
80S LOOK REASONABLE AND WITH THE SYSTEM TONIGHT TAKING PLENTY OF
FOCUS...WILL NOT MAKE ANY CHANGES.
&&
.AVIATION /DISCUSSION FOR THE 130000Z TAFS/...
ISSUED AT 633 PM EDT WED JUN 12 2013
HIGH CONVECTIVE POTENTIAL ACROSS THE TAF SITES LATER THIS EVENING AS
AN UPPER IMPULSE CURRENTLY ENTERING NORTHWEST ILLINOIS MOVES INTO
NORTHWEST OHIO BY 130600Z. AIR MASS STILL CAPPED OFF...BUT VERY
UNSTABLE. CONVECTION SHOULD RESULT IN EITHER COMPLEX OVER NORTHERN
ILLINOIS TURNING SOUTHEAST...OR DEVELOPMENT ALONG THE TRAILING VORT
TAIL. SHORT TERM MODEL DATA SUGGEST HIGHEST CONVECTIVE POTENTIAL
130100Z-130500Z. BRIEF IFR CONDITIONS...AND GUSTY SHIFTING WINDS IN
THE VICINITY OF THE HEAVIER CELLS.
ADDITIONAL CONVECTION POSSIBLE IN THE WAKE OF THIS WAVE ASSOCIATED
WITH THE COLD FRONT. AT THIS POINT...THINK THE FIRST WAVE WILL SWEEP
OUT MOST OF THE INSTABILITY...BUT IF THIS DOESN/T
HAPPEN...CONVECTIVE THREAT WILL BE HIGHER WITH THE FRONT.
OUTSIDE OF CONVECTION...EXPECTING MVFR CEILINGS TO DEVELOP TOWARDS
SUNRISE THURSDAY IN THE POST FRONTAL ZONE. WILL ALSO KEEP SOME
SURFACE WIND GUSTS AROUND 20 KTS FROM 210-230 DEGREES WELL INTO THE
NIGHT.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...50
NEAR TERM...50
SHORT TERM...50
LONG TERM....MK
AVIATION...JAS
VISIT US AT HTTP://WWW.WEATHER.GOV/IND
FOLLOW US ON TWITTER AND YOUTUBE AT:
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AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
430 PM EDT WED JUN 12 2013
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 308 PM EDT WED JUN 12 2013
STRONG TO SEVERE STORMS WILL OCCUR TONIGHT AHEAD OF A COLD FRONT.
RAIN WILL LINGER INTO THURSDAY MORNING...THEN DRY CONDITIONS CAN BE
EXPECTED UNTIL SATURDAY AFTERNOON. A COUPLE OF WEATHER SYSTEMS WILL
KEEP CHANCES FOR RAIN AROUND FROM SATURDAY AFTERNOON INTO NEXT
TUESDAY. TEMPERATURES WILL BE COOLER THAN NORMAL ON THURSDAY BUT
RETURN TO NEAR AVERAGE AND REMAIN THERE FROM THE WEEKEND ON.
&&
.NEAR TERM /LATE THIS AFTERNOON AND TONIGHT/...
ISSUED AT 308 PM EDT WED JUN 12 2013
DECENT CAP SHOULD KEEP CONVECTION AT BAY FOR THE NEXT FEW
HOURS...BUT THEN SCATTERED CONVECTION COULD BREAK THROUGH AS COOLER
AIR FILTERS IN ALOFT. PLENTY OF INSTABILITY AROUND...SO ANY
CONVECTION THAT DOES DEVELOP COULD BECOME SEVERE.
ADDITIONAL THUNDERSTORMS WILL DEVELOP AND MOVE INTO THE AREA THIS
EVENING AND OVERNIGHT AS A COLD FRONT AND UPPER TROUGH MOVES IN. IN
ADDITION THE LEFT EXIT REGION OF AN UPPER JET WILL PROVIDE
ADDITIONAL LIFT.
STILL A HIGH RISK OF SEVERE WEATHER FOR THE EXTREME NORTHERN
FORECAST AREA WITH A MODERATE RISK ELSEWHERE. HIGH INSTABILITY AND
DECENT SHEAR WILL HELP THE POTENTIAL FOR ANY STORM THAT DOES DEVELOP
TO BECOME SEVERE.
THERE IS A CONCERN OVER A POTENTIAL SEVERE SQUALL LINE MOVING ACROSS
NORTHERN INDIANA THIS EVENING INTO EARLY OVERNIGHT. VERY STRONG
WINDS ARE POSSIBLE WITH THIS LINE. THE QUESTION IS HOW FAR SOUTH
WILL IT DEVELOP/MOVE. HRRR MODEL HAS BEEN KEEPING THIS LINE MOSTLY
NORTH OF THE AREA WITH A WEAK TAIL-END OF THE LINE MOVING ACROSS
CENTRAL INDIANA. OTHER MODELS SUCH AS NCEP WRF-NMM SHOW A MUCH
LONGER LINE OF STORMS THAT WILL MOVE ACROSS MOST OF THE AREA.
THUS WHILE SOME SEVERE WEATHER IS LIKELY SOMEWHERE ACROSS THE
NORTHERN FORECAST AREA TONIGHT...UNCERTAINTY IS HIGH ABOUT COVERAGE
OF STORMS ACROSS THE SOUTHERN FORECAST AREA. GIVEN THE FORCING
LISTED EARLIER HAVE DECIDED TO GO AT LEAST LOW END LIKELY POPS MOST
AREAS...WITH CATEGORICAL POPS ACROSS THE FAR NORTH. WILL CONTINUE TO
MENTION SEVERE AND HEAVY RAIN IN PRODUCTS.
FOR TEMPERATURES WENT WITH A BLEND.
&&
.SHORT TERM /THURSDAY THROUGH SATURDAY/...
ISSUED AT 308 PM EDT WED JUN 12 2013
FOCUS IS ON CHANCES FOR RAIN THROUGH THE PERIOD. MODELS ARE CLOSE
ENOUGH THAT A BLEND CAN BE USED.
SOME LINGERING FORCING WILL CONTINUE ACROSS MAINLY THE SOUTHERN AND
EASTERN FORECAST AREA ON THURSDAY MORNING AS SYSTEM EXITS THE AREA.
WENT LIKELY POPS EXTREME EAST TO LOW CHANCE POPS WEST. ENDED CHANCES
FOR RAIN BY AFTERNOON AS THE SYSTEM PULLS EAST.
HIGH PRESSURE WILL THEN PROVIDE DRY CONDITIONS THURSDAY NIGHT INTO
SATURDAY MORNING.
UPPER WAVES RIDING AROUND AN UPPER RIDGE COULD TRIGGER SOME
CONVECTION ACROSS THE AREA SATURDAY AFTERNOON. UNCERTAINTY REMAINS
HIGH IN THE TIMING AND STRENGTH OF THESE WAVES. THEREFORE ONLY WENT
CHANCE POPS SATURDAY AFTERNOON...MAINLY ACROSS THE NORTHWEST
FORECAST AREA CLOSER TO THE FORCING.
FOR TEMPERATURES THROUGH THE PERIOD WENT WITH A BLEND MOST PERIODS.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
ISSUED AT 227 PM EDT WED JUN 12 2013
MODELS AND WEATHER PREDICTION CENTER SUGGEST A COLD FRONT WILL DROP
SOUTHEAST ACROSS CENTRAL INDIANA ON MONDAY FOLLOWED BY AN UPPER WAVE
ON TUESDAY. MOISTURE STREAMING NORTHEAST OFF THE GULF AHEAD OF THE
FRONT SHOULD ALLOW FOR SCATTERED TO NUMEROUS THUNDERSTORMS PRIOR TO
THE FRONTAL PASSAGE WITH LOWER CHANCES AHEAD OF THE UPPER FEATURE.
REGIONAL INITIALIZATION TEMPERATURES NEAR NORMAL IN THE LOWER TO MID
80S LOOK REASONABLE AND WITH THE SYSTEM TONIGHT TAKING PLENTY OF
FOCUS...WILL NOT MAKE ANY CHANGES.
&&
.AVIATION /DISCUSSION FOR THE 122100Z KIND TAF UPDATE/...
ISSUED AT 430 PM EDT WED JUN 12 2013
AIR MASS STILL CAPPED OFF...SO DESPITE A VERY UNSTABLE
ENVIRONMENT...DON/T THINK THERE IS MUCH OF A CONVECTIVE THREAT IN
THE VICINITY OF KIND FOR THE NEXT SEVERAL HOURS. TAIL END OF UPPER
IMPULSE CURRENTLY PUSHING THROUGH IOWA IS EXPECTED TO MOVE THROUGH
THE LOCAL AREA LATER THIS EVENING. THIS FEATURE SHOULD EVENTUALLY
LEAD TO CONVECTIVE DEVELOPMENT AS IT MOVES INTO THE UNSTABLE AIR
MASS. LATEST SHORT TERM MODEL GUIDANCE SUGGESTS BEST CONVECTIVE
THREAT WILL ARRIVE AT KIND AFTER 130200Z-130300Z...SO WILL BACK OFF
ON THE TIMING OF CONVECTION UNTIL THEN.
PREVIOUS DISCUSSION FOLLOWS.
TIMING OF THUNDERSTORMS IS A BIT PROBLEMATIC. THUS...DECIDED TO
WEIGH HEAVILY ON THE MOST CURRENT MESOSCALE BASED 14Z RAPID REFRESH
REFLECTIVITY PROGS. THEY WOULD SUGGEST THAT SCATTERED
STORMS...POSSIBLY SEVERE...WILL DROP SOUTHEAST ACROSS LAF AND IND
AFTER 23Z THIS EVENING. WITH THE TAF SITES IN A MODERATE RISK OF
SEVERE WEATHER...WENT WITH TEMPO MVFR THUNDERSTORM FOLLOWED BY
PROB30 GROUPS AT THOSE SITES THROUGH 08Z WITH WIND GUSTS TO 40
KNOTS. GUSTS WILL LIKELY NEED TO BE ADJUSTED UPWARD IN LATER
TAFS...CLOSER TO THE TIME OF IMPACT. STORMS SHOULD LIKELY HOLD OFF
UNTIL AFTER 02Z AT BMG. HUF HAS THE LOWEST STORM CHANCES BEING
CLOSER TO THE CAP. BUT STILL...TEMPO THUNDERSTORM GROUP LOOKS GOOD
THERE FROM 01Z-05Z. MODELS SUGGEST AN MVFR OR IFR DECK WILL MOVE IN
AFTER 08Z IN THE WAKE OF THE PRECIPITATION SHIELD. BUT AFTER
15Z...CLOUDS SHOULD BECOME VFR AND THEN BREAKUP. WINDS WILL MOSTLY
BE SOUTHWEST NEAR 15 KNOTS WITH GUSTS TO 20 KNOTS THIS AFTERNOON AND
EVENING AWAY FROM STORMS AND THEN SHIFT TO THE WEST AND NORTHWEST AS
THE FRONT MOVES THROUGH AFTER 08Z.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...50
NEAR TERM...50
SHORT TERM...50
LONG TERM....MK
AVIATION...MK/JAS
VISIT US AT HTTP://WWW.WEATHER.GOV/IND
FOLLOW US ON TWITTER AND YOUTUBE AT:
WWW.TWITTER.COM/INDIANAPOLIS
WWW.YOUTUBE.COM/INDIANAPOLIS
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
308 PM EDT WED JUN 12 2013
.UPDATE...
THE SYNOPSIS...NEAR TERM...AND SHORT TERM SECTIONS HAVE BEEN UPDATED
BELOW
&&
.SYNOPSIS...
ISSUED AT 308 PM EDT WED JUN 12 2013
STRONG TO SEVERE STORMS WILL OCCUR TONIGHT AHEAD OF A COLD FRONT.
RAIN WILL LINGER INTO THURSDAY MORNING...THEN DRY CONDITIONS CAN BE
EXPECTED UNTIL SATURDAY AFTERNOON. A COUPLE OF WEATHER SYSTEMS WILL
KEEP CHANCES FOR RAIN AROUND FROM SATURDAY AFTERNOON INTO NEXT
TUESDAY. TEMPERATURES WILL BE COOLER THAN NORMAL ON THURSDAY BUT
RETURN TO NEAR AVERAGE AND REMAIN THERE FROM THE WEEKEND ON.
&&
.NEAR TERM /LATE THIS AFTERNOON AND TONIGHT/...
ISSUED AT 308 PM EDT WED JUN 12 2013
DECENT CAP SHOULD KEEP CONVECTION AT BAY FOR THE NEXT FEW
HOURS...BUT THEN SCATTERED CONVECTION COULD BREAK THROUGH AS COOLER
AIR FILTERS IN ALOFT. PLENTY OF INSTABILITY AROUND...SO ANY
CONVECTION THAT DOES DEVELOP COULD BECOME SEVERE.
ADDITIONAL THUNDERSTORMS WILL DEVELOP AND MOVE INTO THE AREA THIS
EVENING AND OVERNIGHT AS A COLD FRONT AND UPPER TROUGH MOVES IN. IN
ADDITION THE LEFT EXIT REGION OF AN UPPER JET WILL PROVIDE
ADDITIONAL LIFT.
STILL A HIGH RISK OF SEVERE WEATHER FOR THE EXTREME NORTHERN
FORECAST AREA WITH A MODERATE RISK ELSEWHERE. HIGH INSTABILITY AND
DECENT SHEAR WILL HELP THE POTENTIAL FOR ANY STORM THAT DOES DEVELOP
TO BECOME SEVERE.
THERE IS A CONCERN OVER A POTENTIAL SEVERE SQUALL LINE MOVING ACROSS
NORTHERN INDIANA THIS EVENING INTO EARLY OVERNIGHT. VERY STRONG
WINDS ARE POSSIBLE WITH THIS LINE. THE QUESTION IS HOW FAR SOUTH
WILL IT DEVELOP/MOVE. HRRR MODEL HAS BEEN KEEPING THIS LINE MOSTLY
NORTH OF THE AREA WITH A WEAK TAIL-END OF THE LINE MOVING ACROSS
CENTRAL INDIANA. OTHER MODELS SUCH AS NCEP WRF-NMM SHOW A MUCH
LONGER LINE OF STORMS THAT WILL MOVE ACROSS MOST OF THE AREA.
THUS WHILE SOME SEVERE WEATHER IS LIKELY SOMEWHERE ACROSS THE
NORTHERN FORECAST AREA TONIGHT...UNCERTAINTY IS HIGH ABOUT COVERAGE
OF STORMS ACROSS THE SOUTHERN FORECAST AREA. GIVEN THE FORCING
LISTED EARLIER HAVE DECIDED TO GO AT LEAST LOW END LIKELY POPS MOST
AREAS...WITH CATEGORICAL POPS ACROSS THE FAR NORTH. WILL CONTINUE TO
MENTION SEVERE AND HEAVY RAIN IN PRODUCTS.
FOR TEMPERATURES WENT WITH A BLEND.
&&
.SHORT TERM /THURSDAY THROUGH SATURDAY/...
ISSUED AT 308 PM EDT WED JUN 12 2013
FOCUS IS ON CHANCES FOR RAIN THROUGH THE PERIOD. MODELS ARE CLOSE
ENOUGH THAT A BLEND CAN BE USED.
SOME LINGERING FORCING WILL CONTINUE ACROSS MAINLY THE SOUTHERN AND
EASTERN FORECAST AREA ON THURSDAY MORNING AS SYSTEM EXITS THE AREA.
WENT LIKELY POPS EXTREME EAST TO LOW CHANCE POPS WEST. ENDED CHANCES
FOR RAIN BY AFTERNOON AS THE SYSTEM PULLS EAST.
HIGH PRESSURE WILL THEN PROVIDE DRY CONDITIONS THURSDAY NIGHT INTO
SATURDAY MORNING.
UPPER WAVES RIDING AROUND AN UPPER RIDGE COULD TRIGGER SOME
CONVECTION ACROSS THE AREA SATURDAY AFTERNOON. UNCERTAINTY REMAINS
HIGH IN THE TIMING AND STRENGTH OF THESE WAVES. THEREFORE ONLY WENT
CHANCE POPS SATURDAY AFTERNOON...MAINLY ACROSS THE NORTHWEST
FORECAST AREA CLOSER TO THE FORCING.
FOR TEMPERATURES THROUGH THE PERIOD WENT WITH A BLEND MOST PERIODS.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
ISSUED AT 227 PM EDT WED JUN 12 2013
MODELS AND WEATHER PREDICTION CENTER SUGGEST A COLD FRONT WILL DROP
SOUTHEAST ACROSS CENTRAL INDIANA ON MONDAY FOLLOWED BY AN UPPER WAVE
ON TUESDAY. MOISTURE STREAMING NORTHEAST OFF THE GULF AHEAD OF THE
FRONT SHOULD ALLOW FOR SCATTERED TO NUMEROUS THUNDERSTORMS PRIOR TO
THE FRONTAL PASSAGE WITH LOWER CHANCES AHEAD OF THE UPPER FEATURE.
REGIONAL INITIALIZATION TEMPERATURES NEAR NORMAL IN THE LOWER TO MID
80S LOOK REASONABLE AND WITH THE SYSTEM TONIGHT TAKING PLENTY OF
FOCUS...WILL NOT MAKE ANY CHANGES.
&&
.AVIATION /DISCUSSION FOR THE 12/1800Z TAF ISSUANCE/...
ISSUED AT 120 PM EDT WED JUN 12 2013
TIMING OF THUNDERSTORMS IS A BIT PROBLEMATIC. THUS...DECIDED TO
WEIGH HEAVILY ON THE MOST CURRENT MESOSCALE BASED 14Z RAPID REFRESH
REFLECTIVITY PROGS. THEY WOULD SUGGEST THAT SCATTERED
STORMS...POSSIBLY SEVERE...WILL DROP SOUTHEAST ACROSS LAF AND IND
AFTER 23Z THIS EVENING. WITH THE TAF SITES IN A MODERATE RISK OF
SEVERE WEATHER...WENT WITH TEMPO MVFR THUNDERSTORM FOLLOWED BY
PROB30 GROUPS AT THOSE SITES THROUGH 08Z WITH WIND GUSTS TO 40
KNOTS. GUSTS WILL LIKELY NEED TO BE ADJUSTED UPWARD IN LATER
TAFS...CLOSER TO THE TIME OF IMPACT. STORMS SHOULD LIKELY HOLD OFF
UNTIL AFTER 02Z AT BMG. HUF HAS THE LOWEST STORM CHANCES BEING
CLOSER TO THE CAP. BUT STILL...TEMPO THUNDERSTORM GROUP LOOKS GOOD
THERE FROM 01Z-05Z. MODELS SUGGEST AN MVFR OR IFR DECK WILL MOVE IN
AFTER 08Z IN THE WAKE OF THE PRECIPITATION SHIELD. BUT AFTER
15Z...CLOUDS SHOULD BECOME VFR AND THEN BREAKUP. WINDS WILL MOSTLY
BE SOUTHWEST NEAR 15 KNOTS WITH GUSTS TO 20 KNOTS THIS AFTERNOON AND
EVENING AWAY FROM STORMS AND THEN SHIFT TO THE WEST AND NORTHWEST AS
THE FRONT MOVES THROUGH AFTER 08Z.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...50
NEAR TERM...50
SHORT TERM...50
LONG TERM....MK
AVIATION...MK
VISIT US AT HTTP://WWW.WEATHER.GOV/IND
FOLLOW US ON TWITTER AND YOUTUBE AT:
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AREA FORECAST DISCUSSION
NWS PADUCAH KY
225 PM CDT WED JUN 12 2013
.SHORT TERM...(THIS EVENING THROUGH FRIDAY NIGHT)
ISSUED AT 225 PM CDT WED JUN 12 2013
HOT HUMID CONDITIONS PREVAIL ACROSS THE FOUR STATE REGION WITH
HEAT INDEX VALUES FROM THE UPPER 90S TO JUST ABOVE 100F. LAKE
WIND ADVISORY OK FOR NOW AND WILL RUN THROUGH EARLY EVENING WITH
GUSTY SOUTHWEST WINDS CONTINUING.
WVAPOR LOOP SHOWS A VIGOROUS WAVE MOVING INTO SW MINNESOTA AND
SHOULD BE THE FOCUS FOR SIGNIFICANT SEVERE WEATHER OFF TO OUR
NORTH FROM PORTIONS OF IOWA INTO ILLINOIS/INDIANA AND OHIO. THE
QUESTION FOR OUR AREA...IS HOW FAR SOUTH AND WEST CONVECTION WILL
DEVELOP WITH THIS MID LEVEL LOW AND ASSOC SURFACE FRONT THAT WILL
MOVE THROUGH THE REGION LATER TONIGHT INTO EARLY THURSDAY MORNING.
THE HIGH RESOLUTION/MESOSCALE MODELS ARE VARIABLE. A COUPLE OF
4KM MODELS DEVELOP CONVECTION ALL THE WAY TO THE MISSISSIPPI
RIVER. WHILE VARIANTS OF THE HRRR STANDARD AND ENSEMBLE COMPOSITE
DATA SUGGEST A LIMITED CHANCE INTO THE KEVV TRI-STATE IF ANYTHING
AT ALL...AND NOTHING WEST AND SOUTH. GIVEN THE STRONG VEERING MID
LEVEL FLOW AND FALLING HEIGHTS/WEAKENING CAP...THINK IT PRUDENT WE
MAINTAIN POPS FOR CONVECTION TONIGHT INTO MIDDAY THURSDAY FOR NOW
WITH MID RANGE CHANCE POPS KEVV TRI-STATE...LOWERING TO SLIGHT
CHANCE TOWARD THE I-55 CORRIDOR. WOULD NOT BE SURPRISED EITHER WAY
HOW THINGS PAN OUT. AND SHOULD CONVECTION TAKE SHAPE IN OUR
AREA...IT COULD BE SEVERE WITH DAMAGING WINDS THE MAIN HAZARD.
HIGH PRESSURE WILL BUILD IN AND RESULT IN DRY WEATHER FOR THURSDAY
NIGHT THROUGH FRIDAY NIGHT. IN THE WAKE OF THE FRONT AND WITH THE
HIGH BUILDING IN...WE WILL RID THE SHORT LIVED HEAT EPISODE.
.LONG TERM...(SATURDAY THROUGH WEDNESDAY)
ISSUED AT 225 PM CDT WED JUN 12 2013
AT THE BEGINNING OF THIS PERIOD A VERY SHARP...BUT NARROW AMPLITUDE
NORTH TO SOUTH ORIENTED MID-LEVEL RIDGE IS PARKED JUST TO THE WEST
OF THE WFO PAH FORECAST AREA...EXTENDING SOUTH TO THE GULF OF
MEXICO. THE MEAN MOISTURE FLOW AT LOW LEVELS IS ORIENTED FROM THE
SOUTHEAST...WITH HIGH LEVEL MOISTURE MOVING OVER THE RIDGE AND
DIVING SHARPLY SOUTH-SOUTHEAST OVER THE WFO PAH FORECAST AREA FROM
THE UPPER MIDWEST. THERE WILL BE A FAIRLY NARROW...BUT ROBUST
CORRIDOR OF INSTABILITY AND SHEAR TO WORK WITH...BUT THIS SHOULD BE
ENOUGH TO WARRANT THE MENTION OF SHOWERS AND THUNDERSTORMS FROM
NORTHWEST TO SOUTHEAST AS THE WEEKEND PROGRESSES. A SERIES OF MINOR
IMPULSES ROTATING AROUND THE MID-LEVEL RIDGE IN THE MUCH FASTER
WESTERLIES MAY GENERATE NON-DIURNAL RAIN CHANCES. THE BIG KEY WILL
BE THE DEGREE OF DEEP LAYER MOISTURE AVAILABLE FOR CONVECTIVE
ACTIVITY. FOR NOW...KEEPING MOST OF THE WEEKEND RAIN CHANCES IN THE
30 TO 50 PERCENT RANGE FOR POPS.
BY THE TIME SUNDAY AFTERNOON AND EVENING ROLLS AROUND THE MID-LEVEL
RIDGE FLATTENS...SUPPORTING A MUCH MORE ENERGETIC WESTERLY FLOW AND
FORCING OVER THE AREA. THE TRAJECTORY OF MOISTURE IS ALSO MORE
SOUTHERLY AND TARGETED TOWARD THE WFO PAH FORECAST AREA. WITH THIS
IN MIND...RAIN CHANCES WERE INCREASED FROM HIGH CHANCE TO LIKELY BY
EARLY MONDAY...FOCUSED OVER THE SOUTHERN 2/3RDS OF THE WFO PAH
FORECAST AREA. THE RAIN CHANCES ARE ALSO AIDED BY A PROGRESSIVE
SHORTWAVE EXPECTED TO MOVE THROUGH THE AREA DURING THE DAY MONDAY. A
MORE DOMINANT RIDGING TAKES PLACE LATE MONDAY...BRIEFLY REDUCING
CHANCES FOR RAIN DURING THE EVENING HOURS. HOWEVER...UNTIL RIDGING
ALOFT CAPS THE ATMOSPHERE BY MID-WEEK...ANTECEDENT SURFACE
BOUNDARIES/STATIONARY FRONTS SHOULD SUPPORT A SMALL DIURNAL CHANCE
FOR SHOWERS AND THUNDERSTORMS.
GIVEN THE TRAJECTORY OF THE MOISTURE AND VARIABLE CLOUD COVER...THE
HEAT INDEX VALUES SHOULD NOT BE AS STRESSFUL AS WHAT WE ARE
EXPERIENCING TODAY. OTHERWISE...LITTLE CHANGE IN MAX/MIN
TEMPERATURES THROUGH THE PERIOD.
&&
.AVIATION...
ISSUED AT 1137 AM CDT WED JUN 12 2013
GUSTY WSW WINDS EXPECTED THIS AFTERNOON WITH SOME DIURNAL CU.
CONVECTION IS POSSIBLE TONIGHT AND INTO EARLY THURSDAY...ESP KEVV
AND KOWB. LEAST LIKELY KPAH AND KCGI. HOWEVER GIVEN UNCERTAINTY...WILL
LIKELY KEEP IT OUT OF THE TERMINAL FORECASTS AT THIS TIME. WINDS
WILL TURN TO THE WEST AND THEN NORTHWEST THURSDAY MORNING AS A
FRONT MOVES ACROSS THE AREA.
&&
.PAH WATCHES/WARNINGS/ADVISORIES...
IL...LAKE WIND ADVISORY UNTIL 9 PM CDT THIS EVENING FOR ILZ075>078-
080>094.
MO...LAKE WIND ADVISORY UNTIL 9 PM CDT THIS EVENING FOR MOZ076-086-
087-100-107>112-114.
IN...LAKE WIND ADVISORY UNTIL 9 PM CDT THIS EVENING FOR INZ081-082-
085>088.
KY...LAKE WIND ADVISORY UNTIL 9 PM CDT THIS EVENING FOR KYZ001>022.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
457 PM EDT WED JUN 12 2013
.SYNOPSIS...
LOW PRESSURE WILL MOVE ACROSS THE GREAT LAKES AND OHIO VALLEY
REGION THROUGH THURSDAY...FOLLOWED BY BUILDING HIGH PRESSURE LATE
FRIDAY AND SATURDAY.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
500 PM UPDATE...SCATTERED SHOWERS SPREADING SE ACROSS NW SECTIONS
CWA. CAP STILL HOLDING BUT RIGOROUS DEVELOPMENT WELL UPSTREAM IN
IL AND IA. 18Z HRRR DEVELOPS CONVECTION NW OH AND PUSHES SE TO
EDGE OF CWA BY 00Z. WILL CONTINUE TO CLOSELY MONITOR.
REST OF PREVIOUS DISCUSSION FOLLOWS...
CLOUDS FROM A DSPTD TSTM COMPLEX CONT TO STREAM INTO THE RGN.
VERY LITTLE OF WHAT IS ON RADAR IS REACHING THE GROUND. THE
ATMOSPHERE REMAINS CAPPED WITH WARMING AT H7 PER RECENT AIRCRAFT
SOUNDING AND MESO DATA. UPSTREAM SPECIAL 18Z SOUNDINGS SHOW INCRD
CAPPING WITH FURTHER WRM AIR ADVCTN AT H7. THIS IS SPPRTD BY LTL
IF ANY CU ON VSBL STLT. THINK THE LULL IN ACTIVITY WL PERSIST INTO
THE EVE.
STILL EXPTG A TSTM COMPLEX TO DVLP ACRS THE IL/WI/IA AREA AS THE
CAP WKNS AND A SHRTWV MOVES IN. THIS CNVCTN SHOULD MOVE EWD INTO
OUR AREA LATER TNGT. PWATS SHOULD BE INCRG...AND EXP GOOD DYNAMICS
TO SPREAD EWD WITH A DEEPENING SFC LOW AS WELL. SPEED SHEAR AND
ELEVATED INSTAB STILL PLENTY SUFFICIENT TO MAINTAIN TSTMS AS THEY
MOVE INTO THE RGN. HIGHEST CHC FOR SVR TSTMS SHOULD BE OFF TO OUR
WEST...BUT STILL A THREAT FOR SVR INTO OUR RGN WITH ANY COMPLEX
THAT MOVES IN. MOMENTUM AND CNVCTV COLD POOLING SHOULD RESULT IN
DAMAGING WNDS BEING THE MAIN THREAT. WL HAVE TO CLOSELY MONITOR
THIS SITUATION TNGT.
WITH INCRG PWATS AND DYNAMICS INTO THU MRNG...HAVE EXPANDED THE
FLASH FLOOD WATCH FOR THE FORECAST AREA. EXPTG 1-2...WITH LOCALLY
3 INCHES OF RAIN PSBL. FLASH FLOOD GUIDANCE NUMBERS SPPRT THIS ESP
IN URBAN AND FLOOD PRONE AREAS.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH SATURDAY/...
THE SFC LOW AND A CDFNT WL PUSH E OF THE AREA THU AFTN...BRINGING
A GRDL END TO THE SHWRS/TSTMS. LOCALLY HEAVY RAINFALL STILL PSBL
IN THE MRNG. BEST THREAT FOR ANY SVR WEA SHOULD GENLY BE TO OUR E.
A WK VORT MAXES DROPS SE ACRS THE AREA FRI SO ONLY MENTIONED SLGT
CHC POPS FOR SHWRS. HIGH PRES QUICKLY BLDS IN LTR FRI AND SAT WITH
CLRG CONDS.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
THE LONG WAVE PATTERN LOOKS TO FAVOR TROUGHING OVER THE GREAT LAKES
AND NORTHEASTERN REGION OF THE COUNTRY THROUGH THE PERIOD WITH
SEVERAL ILL-TIMED SHORT WAVE SYSTEMS LIKELY TO EVOLVE IN THE
NORTHWESTERLY FLOW ALOFT. THIS WILL BRING CHANCES OF SHOWERS AND
THUNDERSTORMS THROUGH MOST OF THE EXTENDED FORECAST. THIS SHOULD
KEEP TEMPERATURES FROM REALLY GETTING TOO WARM DURING ANY PARTICULAR
PERIOD OF THE LONG TERM AT LEAST UNTIL MID-WEEK NEXT WEEK. BY THAT
TIME...LONG WAVE RIDGING SHOULD START TO EDGE FROM THE PLAINS TOWARD
THE WESTERN GREAT LAKES...BRINGING A GRADUAL END TO UNSETTLED
CONDITIONS OVER OUR REGION.
&&
.AVIATION /21Z WEDNESDAY THROUGH MONDAY/...
GENERAL VFR IS EXPECTED INTO THE LATE AFTERNOON. LATEST MODEL
SOUNDINGS SHOW SOME CAPPING STILL TO OVERCOME...AND HI RES
MODELS SHOW SCT STORMS POSSIBLE LATE AFTERNOON BUT NOTHING
WIDESPREAD AND HAVE KEPT VCTS UNTIL NEAR SUNSET.
SHOWERS/THUNDERSTORMS BECOME LIKELY 01-03Z WEST AND 04-06Z EAST AS
SURFACE LOW GAINS STRENGTH OVER THE LOWER OHIO VALLEY...WITH
PREVAILING TSRA CONTINUED UNTIL 08-09Z. LOCAL IFR CONDITIONS WILL BE
POSSIBLE IN THE HEAVIEST CELLS. TIMING WILL LIKELY NEED TO BE
ADJUSTED BASED ON DEVELOPMENT OF ANY CONVECTIVE COMPLEX. LOW
PRESSURE SYSTEM WILL THEN WRAP UP AS IT CROSSES THE RIDGES THURSDAY
MORNING WITH COLD FRONT PUSHING EAST ACROSS THE REGION MID MORNING
TO EARLY AFTERNOON. LOW LEVEL WIND SHEAR MAINTAINED FOR THE
OVERNIGHT HOURS AS LOW LEVEL JET WILL BE RIDING OVER DEVELOPING
INVERSION OVERNIGHT. RESTRICTIONS IN SHOWERS WILL END NORTHWEST TO
SOUTHEAST THURSDAY AS COLD FRONT SWEEPS EAST.
.OUTLOOK.../THURSDAY NIGHT THROUGH SUNDAY/...
HIGH PRES WL RTN VFR TO REGIONAL PORTS FOR FRI AND SAT. PCPN AND
RESTRICTION CHCS WL INCRS AGAIN SUNDAY INTO MONDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...FLASH FLOOD WATCH FROM 10 PM EDT THIS EVENING THROUGH THURSDAY
AFTERNOON FOR MDZ001.
OH...FLASH FLOOD WATCH FROM 10 PM EDT THIS EVENING THROUGH THURSDAY
AFTERNOON FOR OHZ039>041-048>050-057>059-068-069.
PA...FLASH FLOOD WATCH FROM 10 PM EDT THIS EVENING THROUGH THURSDAY
AFTERNOON FOR PAZ007>009-013>016-020>023-029-031-073>076.
WV...FLASH FLOOD WATCH FROM 10 PM EDT THIS EVENING THROUGH THURSDAY
AFTERNOON FOR WVZ001>004-012-021>023-041.
&&
$$
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
700 PM EDT WED JUN 12 2013
LATEST UPDATE...
AVIATION
.SYNOPSIS...
ISSUED AT 339 PM EDT WED JUN 12 2013
STRONG LOW PRESSURE SYSTEM WILL BRING THUNDERSTORMS... SOME POSSIBLY
SEVERE WITH HEAVY RAINFALL OVERNIGHT CAUSING LOCAL FLOODING. SOME
CLEARING
BY THURSDAY AFTERNOON CONTINUING INTO FRIDAY.
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY NIGHT)
ISSUED AT 339 PM EDT WED JUN 12 2013
LATEST MODEL TRENDS SUGGEST RISK OF SEVERE THUNDERSTORMS EARLY TO
MID EVENING. THERE IS A THREAT OF HEAVY RAINFALL SOUTH OF
INTERSTATE 96.
WE EXPECT A LOW LEVEL JET FOCUSED SOUTH OF I-80 INTO THE EVENING
THAT WILL RESULT IN THE STRONGEST THUNDERSTORMS TRACKING SOUTH
INTO I-94 INTO THE EARLY EVENING. THE STRONG UPPER DYNAMICS WILL
DEVELOP THE DIGGING SHORTWAVE WILL RESULT IN A TROWAL ON THE NORTH
SIDE OF THE SYSTEM OVERNIGHT THAT WILL RESULT IN A BAND OF
PERSISTENT HEAVY RAINFALL. WE EXPECT THUNDERSTORM COMPLEX TO
DEVELOP WEST OF CHICAGO BY 6 PM THEN TRACK EAST SOUTHEAST ALONG
THE MICHIGAN INDIANA BORDER DURING THE EARLY EVENING. RAINFALL
AMOUNTS OF 2 TO 3 INCHES ARE SUGGESTED BY THE HRRR... RAP AND SPC
WRF. THIS RAINFALL IS INDEPENDENT OF THE THUNDERSTORM COMPLEX THIS
EVENING.
THIS SYSTEM SHOULD EXIT THE AREA BY THE MID MORNING HOURS
THURSDAY. A TRAILING SHORTWAVE AND SECONDARY COLD FRONT DIVING
SOUTH ON THE NORTHERN STREAM JET WILL INTERACT WITH THE LAKE
MICHIGAN AND LAKE HURON LAKE BREEZE THURSDAY AFTERNOON TO CREATE
INSTABILITY SHOWERS.
RIDGING WILL MOVE INTO THE AREA THURSDAY NIGHT INTO FRIDAY
BRINGING CLEARING SKIES AND COOLER TEMPERATURES.
.LONG TERM...(SATURDAY THROUGH WEDNESDAY)
ISSUED AT 339 PM EDT WED JUN 12 2013
A COUPLE OF LOW PRESSURE SYSTEMS WILL BRING POTENTIAL FOR SCATTERED
SHOWERS AND THUNDERSTORMS FROM LATE SATURDAY THROUGH SUNDAY AND
MONDAY. BEYOND THAT A CONSENSUS OF LATEST MEDIUM RANGE GUIDANCE
INCLUDING THE 12Z GFS AND 00Z ECMWF SUGGESTS HIGH PRESSURE SHOULD
BUILD IN AND BRING FAIR WX FOR THE MIDDLE PORTION OF NEXT WEEK.
TEMPS SHOULD AVERAGE RATHER CLOSE TO NORMAL THROUGH THE LONG RANGE
FORECAST PERIOD.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z FRIDAY)
ISSUED AT 700 PM EDT WED JUN 12 2013
PRIMARY AVIATION CONCERN CONTINUES TO BE ON SEVERE THUNDERSTORMS
THAT WILL LIKELY IMPACT KAZO... KBTL AND KJXN DURING THE MID TO LATE
EVENING HOURS. A FAST MOVING COMPLEX OF SEVERE STORMS IS LIKELY TO
IMPACT THESE TERMINALS FROM 02Z THROUGH 06Z WITH POTENTIAL FOR VERY
SIGNIFICANT WIND GUSTS IN ADDITION TO FREQUENT LIGHTNING... HEAVY
RAIN AND HAIL.
AT THIS TIME WE ARE FORECASTING WIND GUSTS TO POTENTIALLY REACH 45
KTS IN THE STORMS BUT POTENTIALLY WIND GUSTS COULD BE EVEN HIGHER IF
AN ORGANIZED BOW ECHO MOVES ACROSS THE I-94 CORRIDOR LATE THIS
EVENING.
SHOWERS AND THUNDERSTORMS WILL ALSO LIKELY IMPACT THE TERMINALS
FURTHER NORTH (KMKG... KGRR AND KLAN) FROM MID TO LATE EVENING BUT
THOSE STORMS ARE NOT LIKELY TO BE SEVERE.
NORTHERLY WINDS WILL DEVELOP LATE TONIGHT IN THE WAKE OF THE STORMS
WITH MVFR CEILINGS AND POSSIBLY VSBY/S (FOG) DEVELOPING. CONDITIONS
WILL IMPROVE TO VFR BY MID TO LATE MORNING THURSDAY WITH NNW WINDS
GUSTING UP TO AROUND 20 KTS AND JUST SOME SCT HIGH CLOUD COVER.
&&
.MARINE...
ISSUED AT 339 PM EDT WED JUN 12 2013
WE ISSUED A SMALL CRAFT ADVISORY TONIGHT THROUGH THURSDAY NIGHT
DUE TO 20 TO 25 KNOT NORTH WINDS BEHIND THE SYSTEM WITH STRONG
COLD AIR ADVECTION.
WE ADDED FOG TO THE NEARSHORE WATERS BASED ON WEB CAMS AND
DEW POINTS IN THE UPPER 60S WHICH IS HIGHER THAN THE MID 50S LAKE
TEMPERATURES. ONCE WIND SHIFTS MID EVENING TO THE NORTH AND
BRINGS DRIER AIR IN THE FOG DISPERSE.
&&
.HYDROLOGY...
ISSUED AT 339 PM EDT WED JUN 12 2013
THERE IS A THREAT FOR FLASH FLOODING TONIGHT AS THE MODELS SUGGEST
2 TO 3 INCHES OF RAIN ALONG THE I-94 CORRIDOR. THIS IS THE RESULT
OF TROWAL DEVELOPING ON THE NORTH SIDE OF THE INTENSIFYING SURFACE
LOW. THE LATEST FLASH FLOODING GUIDANCE FROM THE NCRFC SUGGESTS
RAINFALL AMOUNTS OF MORE THAN 2 INCHES IN 6 HOURS WILL GENERATE
FLASH FLOODING OVER THE SOUTHERN TWO ROWS OF COUNTIES.
PRECIPITABLE WATER VALUES FORECAST 1.75 INCHES THIS EVENING. THIS
IS BETWEEN 2 AND 3 STANDARD DEVIATIONS FROM NORMAL. WHEN YOU ADD
THAT TO THE DYNAMICS FORECAST TO THE AREA RESULTS IN A FLASH FLOOD
THREAT SO WE ISSUED A FLASH FLOOD WATCH OVER THE SOUTHERN TWO ROWS
OF COUNTIES WHERE THE HEAVIEST RAINFALL WILL OCCUR.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...FLASH FLOOD WATCH FROM 8 PM EDT THIS EVENING THROUGH THURSDAY
MORNING FOR MIZ064>067-071>074.
LM...SMALL CRAFT ADVISORY FROM 8 PM THIS EVENING TO 8 AM EDT FRIDAY
FOR LMZ844>849.
&&
$$
SYNOPSIS...WDM
SHORT TERM...WDM
LONG TERM...LAURENS
AVIATION...LAURENS
HYDROLOGY...WDM
MARINE...WDM
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
342 PM EDT WED JUN 12 2013
LATEST UPDATE...
SYNOPSIS/SHORT TERM/LONG TERM/HYDRO/MARINE
.SYNOPSIS...
ISSUED AT 339 PM EDT WED JUN 12 2013
STRONG LOW PRESSURE SYSTEM WILL BRING THUNDERSTORMS... SOME POSSIBLY
SEVERE WITH HEAVY RAINFALL OVERNIGHT CAUSING LOCAL FLOODING. SOME CLEARING
BY THURSDAY AFTERNOON CONTINUING INTO FRIDAY.
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY NIGHT)
ISSUED AT 339 PM EDT WED JUN 12 2013
LATEST MODEL TRENDS SUGGEST RISK OF SEVERE THUNDERSTORMS EARLY TO
MID EVENING. THERE IS A THREAT OF HEAVY RAINFALL SOUTH OF
INTERSTATE 96.
WE EXPECT A LOW LEVEL JET FOCUSED SOUTH OF I-80 INTO THE EVENING
THAT WILL RESULT IN THE STRONGEST THUNDERSTORMS TRACKING SOUTH
INTO I-94 INTO THE EARLY EVENING. THE STRONG UPPER DYNAMICS WILL
DEVELOP THE DIGGING SHORTWAVE WILL RESULT IN A TROWAL ON THE NORTH
SIDE OF THE SYSTEM OVERNIGHT THAT WILL RESULT IN A BAND OF
PERSISTENT HEAVY RAINFALL. WE EXPECT THUNDERSTORM COMPLEX TO
DEVELOP WEST OF CHICAGO BY 6 PM THEN TRACK EAST SOUTHEAST ALONG
THE MICHIGAN INDIANA BORDER DURING THE EARLY EVENING. RAINFALL
AMOUNTS OF 2 TO 3 INCHES ARE SUGGESTED BY THE HRRR... RAP AND SPC
WRF. THIS RAINFALL IS INDEPENDENT OF THE THUNDERSTORM COMPLEX THIS
EVENING.
THIS SYSTEM SHOULD EXIT THE AREA BY THE MID MORNING HOURS
THURSDAY. A TRAILING SHORTWAVE AND SECONDARY COLD FRONT DIVING
SOUTH ON THE NORTHERN STREAM JET WILL INTERACT WITH THE LAKE
MICHIGAN AND LAKE HURON LAKE BREEZE THURSDAY AFTERNOON TO CREATE
INSTABILITY SHOWERS.
RIDGING WILL MOVE INTO THE AREA THURSDAY NIGHT INTO FRIDAY
BRINGING CLEARING SKIES AND COOLER TEMPERATURES.
.LONG TERM...(SATURDAY THROUGH WEDNESDAY)
ISSUED AT 339 PM EDT WED JUN 12 2013
A COUPLE OF LOW PRESSURE SYSTEMS WILL BRING POTENTIAL FOR SCATTERED
SHOWERS AND THUNDERSTORMS FROM LATE SATURDAY THROUGH SUNDAY AND
MONDAY. BEYOND THAT A CONSENSUS OF LATEST MEDIUM RANGE GUIDANCE
INCLUDING THE 12Z GFS AND 00Z ECMWF SUGGESTS HIGH PRESSURE SHOULD
BUILD IN AND BRING FAIR WX FOR THE MIDDLE PORTION OF NEXT WEEK.
TEMPS SHOULD AVERAGE RATHER CLOSE TO NORMAL THROUGH THE LONG RANGE
FORECAST PERIOD.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY)
ISSUED AT 100 PM EDT WED JUN 12 2013
VFR CONDITIONS SHOULD CONTINUE AT ALL THE TERMINALS THIS AFTERNOON
WITH FAIRLY EXTENSIVE MID CLOUD COVER AND A FEW SHOWERS.
PRIMARY AVIATION CONCERN IS ON SEVERE THUNDERSTORMS THAT WILL LIKELY
IMPACT KAZO... KBTL AND KJXN DURING THE MID TO LATE EVENING HOURS. A
FAST MOVING COMPLEX OF SEVERE STORMS IS LIKELY TO IMPACT THESE
TERMINALS FROM 01Z THROUGH 06Z WITH POTENTIAL FOR VERY SIGNIFICANT
WIND GUSTS IN ADDITION TO FREQUENT LIGHTNING... HEAVY RAIN AND HAIL.
NORTHERLY WINDS WILL DEVELOP TONIGHT IN THE WAKE OF THE STORMS WITH
MVFR CEILINGS AND POSSIBLY VSBY/S (FOG) DEVELOPING.
&&
.MARINE...
ISSUED AT 339 PM EDT WED JUN 12 2013
WE ISSUED A SMALL CRAFT ADVISORY TONIGHT THROUGH THURSDAY NIGHT
DUE TO 20 TO 25 KNOT NORTH WINDS BEHIND THE SYSTEM WITH STRONG
COLD AIR ADVECTION.
WE ADDED FOG TO THE NEARSHORE WATERS BASED ON WEB CAMS AND
DEW POINTS IN THE UPPER 60S WHICH IS HIGHER THAN THE MID 50S LAKE
TEMPERATURES. ONCE WIND SHIFTS MID EVENING TO THE NORTH AND
BRINGS DRIER AIR IN THE FOG DISPERSE.
&&
.HYDROLOGY...
ISSUED AT 339 PM EDT WED JUN 12 2013
THERE IS A THREAT FOR FLASH FLOODING TONIGHT AS THE MODELS SUGGEST
2 TO 3 INCHES OF RAIN ALONG THE I-94 CORRIDOR. THIS IS THE RESULT
OF TROWAL DEVELOPING ON THE NORTH SIDE OF THE INTENSIFYING SURFACE
LOW. THE LATEST FLASH FLOODING GUIDANCE FROM THE NCRFC SUGGESTS
RAINFALL AMOUNTS OF MORE THAN 2 INCHES IN 6 HOURS WILL GENERATE
FLASH FLOODING OVER THE SOUTHERN TWO ROWS OF COUNTIES.
PRECIPITABLE WATER VALUES FORECAST 1.75 INCHES THIS EVENING. THIS
IS BETWEEN 2 AND 3 STANDARD DEVIATIONS FROM NORMAL. WHEN YOU ADD
THAT TO THE DYNAMICS FORECAST TO THE AREA RESULTS IN A FLASH FLOOD
THREAT SO WE ISSUED A FLASH FLOOD WATCH OVER THE SOUTHERN TWO ROWS
OF COUNTIES WHERE THE HEAVIEST RAINFALL WILL OCCUR.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...FLASH FLOOD WATCH FROM 8 PM EDT THIS EVENING THROUGH THURSDAY
MORNING FOR MIZ064>067-071>074.
LM...SMALL CRAFT ADVISORY FROM 8 PM THIS EVENING TO 8 AM EDT FRIDAY
FOR LMZ844>849.
&&
$$
SYNOPSIS...WDM
SHORT TERM...WDM
LONG TERM...LAURENS
AVIATION...LAURENS
HYDROLOGY...WDM
MARINE...WDM
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
204 PM EDT WED JUN 12 2013
LATEST UPDATE...
UPDATE
.SYNOPSIS...
ISSUED AT 330 AM EDT WED JUN 12 2013
AS LOW PRESSURE MOVES EAST FROM THE PLAINS TOWARD NORTHERN INDIANA
TODAY SHOWERS AND THUNDERSTORMS WILL DEVELOP. SOME OF THE STORMS
COULD BE STRONG TO SEVERE ESPECIALLY SOUTH OF I-94 WITH HIGH WINDS
THE MAIN THREAT. HEAVY RAIN WILL BE POSSIBLE THIS AFTERNOON AND
EVENING TOO SOUTH OF I-96. QUIETER WEATHER WILL RETURN THURSDAY
THROUGH SATURDAY AS THE LOW MOVES EAST AND NORTH WINDS ADVECT DRIER
AIR INTO LOWER MICHIGAN.
&&
.UPDATE...
ISSUED AT 203 PM EDT WED JUN 12 2013
I HAVE ISSUED A FLASH FLOOD WATCH BASED ON THE POTENTIAL FOR HEAVY
RAIN WITH THE TROWAL FEATURE NORTH OF THE MAIN UPPER LEVEL WAVE
AS IT COMES THROUGH TONIGHT. THE SPC SREF...THE 15Z HRRR AND THE
15Z ESRL RAP MODELS ALL SHOW 2 TO 3 INCHES OF RAIN TONIGHT JUST
SOUTH OF INTERSTATE 96. GIVEN THE CONVECTIVE NATURE OF THE EVENT
IT WOULD SEEM REASONABLE THAT FLASH FLOODING IS POSSIBLE IN THIS
AREA.
IT STILL LOOKS LIKE THE STRONG THUNDERSTORMS WILL CROSS OUR AREA
AFTER 10 PM TONIGHT AND THOSE STORMS WOULD SEEM TO WANT TO TRACK
SOUTH OF INTERSTATE 94. STILL THERE WOULD BE A LARGE AREA OF HEAVY
RAIN NORTH OF THAT... MAYBE AS FAR NORTH AS INTERSTATE 96.
&&
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 330 AM EDT WED JUN 12 2013
FORECAST CONCERNS DEAL WITH CONVECTIVE TRENDS THIS MORNING THROUGH
THIS EVENING.
LATEST REGIONAL RADAR SHOWS THAT STORMS HAVE FIRED AS EXPECTED IN
NORTHEAST NEBRASKA ON THE NOSE OF A STRONG LLJ. THESE STORMS HAVE
MOVED INTO NW IOWA. A BIT FARTHER NORTH OVER SOUTH DAKOTA ANOTHER
AREA OF STORMS IS MOVE EWD. THESE ARE ASSOCIATED WITH A SHORT WAVE
MOVING ACROSS THE NRN PLAINS. SHORT RANGE MODELS MOVE THIS SHORT
WAVE SEWD TOWARD CHICAGO BY THIS AFTERNOON AT THE SAME TIME THE SFC
LOW IN SRN NEBRASKA IS MOVING ENEWD. HRRR SHOWS BOTH CLUSTERS OF
STORMS WEAKENING AS THEY MOVE EAST WITH THE IOWA CONVECTION MOVING
TO THE WRN CWA BY NOON OR SO AS MOSTLY SHOWERS.
CONVECTION REDEVELOPS OVER NW IOWA BY EARLY AFTERNOON AS STRONG
DYNAMICS TAKE SHAPE. SBCAPE AROUND 3K J/KG COUPLED WITH STRONG
MOISTURE CONVERGENCE...60-70KTS BULK SHEAR AND LIFT FROM THE
APPROACHING SHORT WAVE SHOULD RESULT IN STRONG TO SEVERE STORMS
DEVELOPING OVER ILLINOIS AND MOVING ESE TOWARD THE SRN CWA. A 50KT
MID LEVEL JET WILL PUSH THE STORMS EWD...PERHAPS AS A DERECHO. CAN/T
ARGUE TOO MUCH WITH THE POSITION OF THE DAY ONE SLIGHT AND MODERATE
RISK AREAS. THIS ISN/T A SLAM DUNK BY ANY MEANS BUT THE HIGHEST
THREAT FOR STRONG/SVR STORMS WILL BE SOUTH OF A MUSKEGON TO LANSING
LINE. LATEST NAM ALSO PUSHES THE WARM FRONT INTO THE SRN CWA THIS
AFTERNOON. SO...WITH THE WARM FRONT IN PLACE WE CAN/T RULE OUT A
TORNADO EITHER.
THE SVR THREAT WILL END THIS EVENING AS THE LOW MOVES BY TO THE
SOUTH AND QUIETER WEATHER WILL RETURN THURSDAY AND FRIDAY.
.LONG TERM...(FRIDAY NIGHT THROUGH TUESDAY)
ISSUED AT 330 AM EDT WED JUN 12 2013
UPPER RIDGING WILL EXTEND FROM THE GULF COAST NORTH INTO THE UPPER
MID WEST FRIDAY NIGHT. THE RIDGING WILL BE FLATTENED THROUGH THE
LONG TERM AS A SERIES OF SHORTWAVE/S CREST THE RIDGE AND MOVE
THROUGH THE GREAT LAKES REGION. THE FIRST OF WHICH MOVES INTO THE
AREA ON SATURDAY. THE SECOND AND MORE SUBSTANTIAL WAVE DIGS INTO THE
GREAT LAKES REGION SUNDAY INTO MONDAY.
AT THE SURFACE RIDGING WILL BE IN PLACE FRIDAY NIGHT AND BRING DRY
WEATHER. THE HIGH SLIPS EAST QUICKLY ON SATURDAY WHICH SHOULD ALLOW
CHANCES FOR SHOWERS AND STORMS DURING THE AFTERNOON AHEAD OF THE
UPPER SHORTWAVE. THE CHANCES WILL CONTINUE INTO SATURDAY NIGHT AS A
WAVE OF LOW PRESSURE SLIDES THROUGH THE AREA AT THE SURFACE.
SUNDAY INTO MONDAY CHANCES FOR SHOWERS AND STORMS WILL CONTINUE AS
THE SECOND MORE POTENT UPPER TROUGH DIGS INTO THE GREAT LAKES.
SURFACE FEATURES ARE BIT MORE HARD TO DISCERN IN THIS TIME FRAME AS
THE GFS IS FURTHER NORTH AND DEEPER WITH THE SURFACE WAVE. FOLLOWED
THE GFS CLOSER HERE AS IT MAKES MORE SENSE TO HAVE A DEEPER FARTHER
NORTH WAVE GIVEN THE UPPER PATTERN. WE LOOK TO DRY OUT MONDAY NIGHT
INTO TUESDAY AS HIGH PRESSURE BUILDS IN.
TEMPERATURES THROUGH THE PERIOD SHOULD BE SEASONABLE DESPITE THE
RIDGING DAMPENING OUT. HEIGHTS ARE STILL FAIRLY HIGH AND 850MB TEMPS
ARE FORECAST TO BE IN THE TEENS C. HIGHS SHOULD BE IN THE UPPER 70S
TO AROUND 80 EACH DAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY)
ISSUED AT 100 PM EDT WED JUN 12 2013
VFR CONDITIONS SHOULD CONTINUE AT ALL THE TERMINALS THIS AFTERNOON
WITH FAIRLY EXTENSIVE MID CLOUD COVER AND A FEW SHOWERS.
PRIMARY AVIATION CONCERN IS ON SEVERE THUNDERSTORMS THAT WILL LIKELY
IMPACT KAZO... KBTL AND KJXN DURING THE MID TO LATE EVENING HOURS. A
FAST MOVING COMPLEX OF SEVERE STORMS IS LIKELY TO IMPACT THESE
TERMINALS FROM 01Z THROUGH 06Z WITH POTENTIAL FOR VERY SIGNIFICANT
WIND GUSTS IN ADDITION TO FREQUENT LIGHTNING... HEAVY RAIN AND HAIL.
NORTHERLY WINDS WILL DEVELOP TONIGHT IN THE WAKE OF THE STORMS WITH
MVFR CEILINGS AND POSSIBLY VSBY/S (FOG) DEVELOPING.
&&
.MARINE...
ISSUED AT 330 AM EDT WED JUN 12 2013
FAIRLY LIGHT WINDS WILL CONTINUE OVER THE LAKE RESULTING IN LOW WAVE
HEIGHTS. PATCHY DENSE FOG IS POSSIBLE DUE TO HIGH DEWPOINTS OVER THE
COLDER WATER SFC. NORTH WINDS WILL DEVELOP THURSDAY AND A SMALL
CRAFT ADVISORY MAY BE NEEDED.
&&
.HYDROLOGY...
ISSUED AT 330 AM EDT WED JUN 12 2013
THE MAIN PERIOD OF CONCERN IS THIS AFTERNOON AND EVENING. HEAVY
RAINFALL WILL BE POSSIBLE ACROSS THE SRN HALF OF THE CWA DURING THIS
TIME. AN INCH TO TWO INCHES SEEMS PLAUSIBLE ESPECIALLY SOUTH OF
I-94. THIS MAY LEAD TO LOCALIZED FLOODING.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...FLASH FLOOD WATCH FROM 8 PM EDT THIS EVENING THROUGH THURSDAY
MORNING FOR MIZ064>067-071>074.
LM...NONE.
&&
$$
UPDATE...WDM
SYNOPSIS...93
SHORT TERM...93
LONG TERM...DUKE
AVIATION...LAURENS
HYDROLOGY...93
MARINE...93
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
100 PM EDT WED JUN 12 2013
LATEST UPDATE...
AVIATION
.SYNOPSIS...
ISSUED AT 330 AM EDT WED JUN 12 2013
AS LOW PRESSURE MOVES EAST FROM THE PLAINS TOWARD NORTHERN INDIANA
TODAY SHOWERS AND THUNDERSTORMS WILL DEVELOP. SOME OF THE STORMS
COULD BE STRONG TO SEVERE ESPECIALLY SOUTH OF I-94 WITH HIGH WINDS
THE MAIN THREAT. HEAVY RAIN WILL BE POSSIBLE THIS AFTERNOON AND
EVENING TOO SOUTH OF I-96. QUIETER WEATHER WILL RETURN THURSDAY
THROUGH SATURDAY AS THE LOW MOVES EAST AND NORTH WINDS ADVECT DRIER
AIR INTO LOWER MICHIGAN.
&&
.UPDATE...
ISSUED AT 1209 PM EDT WED JUN 12 2013
WE ADDED SEVERE WEATHER TO OUR GRIDS TO MATCH THE THIRTY PERCENT
AREA OF THE LATEST SPC OUTLOOK. WE DID THIS FROM 5PM TO 11PM
BECAUSE THE SPC MODELS WERE SHOWING THE HIGHEST PROBABILITY DURING
THAT TIME FRAME.
AN AREA OF SHOWERS OVER EASTERN WISCONSIN TO SOUTHERN LAKE MICHIGAN
IS MOVING INTO THE CWA OVER THE NEXT FEW HOURS. IN SPITE OF THE
INCREASING INSTABILITY WE DO NOT EXPECT STRONG THUNDERSTORM
DEVELOPMENT AS THERE IS TOO MUCH CONVECTIVE INHIBITION AND MID
LEVEL DRY AIR.
UPDATE ISSUED AT 1043 AM EDT WED JUN 12 2013
MY CURRENT THINKING IS THE BEST THREAT FOR SEVERE STORMS WILL BE
THIS EVENING INTO EARLY TONIGHT. THE DENSE MID AND HIGH CLOUD
COVER OVER MN/WI/LWR MI WILL CAUSE THE BEST DESTABILIZATION TO BE
WELL SOUTH OF OUR AREA THIS AFTERNOON. SO... THE STRONGEST
THUNDERSTORMS WILL BE ASSOCIATED WITH THE MAIN UPPER LEVEL WAVE
MOVING THROUGH THIS EVENING. THIS IDEA IS SUPPORTED BY THE LATEST
12Z NAM...12Z HRRR...00Z SPC WRF...12 RAP MODELS.
THE BEST FORCING (MOISTURE TRANSPORT VECTORS 1000/850...LOW LEVEL
JET AND THERMAL GRADIENT...HIGHEST MIXED LAYER CAPE) ARE ALL WELL
SOUTH OF INTERSTATE 94 AND ACTUALLY NEAR AND SOUTH OF INTERSTATE
80 AS THE UPPER WAVE MOVES THROUGH EARLY TONIGHT. WE SHOULD SEE
SOME CONVECTION OVER OUR SRN ONE OR TWO ROWS OF COUNTIES MID
EVENING AS THE WAVE MOVES IN. DEFORMATION ZONE RAIN WILL FOLLOW
DURING THE OVERNIGHT HOURS. THE HEAVIEST OF THAT WILL BE NEAR AND
SOUTH OF INTERSTATE 94.
THERE IS A CONVECTIVE COMPLEX OVER E CNTL MN AT 10 AM HEADING
EAST. THAT IS ON THE TAIL OF THE PV MAX ASSOCIATED WITH THE
CONVECTION THAT CROSSED MN AND WI EARLIER AND HAS SINCE DIED. THAT
PV MAX MOVES THROUGH OUR CNTL CWA THIS AFTERNOON. I BELIEVE THAT
WILL BE THE FOCUS FOR OUR AFTERNOON CONVECTION. THE INSTABILITY IS
MARGINAL (LOOKING AT RAP SOUNDING THIS AFTERNOON) FOR THIS
CONVECTION SO I DO NOT BELIEVE THIS WILL BE SEVERE... MOSTLY JUST
GENERIC THUNDERSTORMS.
&&
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 330 AM EDT WED JUN 12 2013
FORECAST CONCERNS DEAL WITH CONVECTIVE TRENDS THIS MORNING THROUGH
THIS EVENING.
LATEST REGIONAL RADAR SHOWS THAT STORMS HAVE FIRED AS EXPECTED IN
NORTHEAST NEBRASKA ON THE NOSE OF A STRONG LLJ. THESE STORMS HAVE
MOVED INTO NW IOWA. A BIT FARTHER NORTH OVER SOUTH DAKOTA ANOTHER
AREA OF STORMS IS MOVE EWD. THESE ARE ASSOCIATED WITH A SHORT WAVE
MOVING ACROSS THE NRN PLAINS. SHORT RANGE MODELS MOVE THIS SHORT
WAVE SEWD TOWARD CHICAGO BY THIS AFTERNOON AT THE SAME TIME THE SFC
LOW IN SRN NEBRASKA IS MOVING ENEWD. HRRR SHOWS BOTH CLUSTERS OF
STORMS WEAKENING AS THEY MOVE EAST WITH THE IOWA CONVECTION MOVING
TO THE WRN CWA BY NOON OR SO AS MOSTLY SHOWERS.
CONVECTION REDEVELOPS OVER NW IOWA BY EARLY AFTERNOON AS STRONG
DYNAMICS TAKE SHAPE. SBCAPE AROUND 3K J/KG COUPLED WITH STRONG
MOISTURE CONVERGENCE...60-70KTS BULK SHEAR AND LIFT FROM THE
APPROACHING SHORT WAVE SHOULD RESULT IN STRONG TO SEVERE STORMS
DEVELOPING OVER ILLINOIS AND MOVING ESE TOWARD THE SRN CWA. A 50KT
MID LEVEL JET WILL PUSH THE STORMS EWD...PERHAPS AS A DERECHO. CAN/T
ARGUE TOO MUCH WITH THE POSITION OF THE DAY ONE SLIGHT AND MODERATE
RISK AREAS. THIS ISN/T A SLAM DUNK BY ANY MEANS BUT THE HIGHEST
THREAT FOR STRONG/SVR STORMS WILL BE SOUTH OF A MUSKEGON TO LANSING
LINE. LATEST NAM ALSO PUSHES THE WARM FRONT INTO THE SRN CWA THIS
AFTERNOON. SO...WITH THE WARM FRONT IN PLACE WE CAN/T RULE OUT A
TORNADO EITHER.
THE SVR THREAT WILL END THIS EVENING AS THE LOW MOVES BY TO THE
SOUTH AND QUIETER WEATHER WILL RETURN THURSDAY AND FRIDAY.
.LONG TERM...(FRIDAY NIGHT THROUGH TUESDAY)
ISSUED AT 330 AM EDT WED JUN 12 2013
UPPER RIDGING WILL EXTEND FROM THE GULF COAST NORTH INTO THE UPPER
MID WEST FRIDAY NIGHT. THE RIDGING WILL BE FLATTENED THROUGH THE
LONG TERM AS A SERIES OF SHORTWAVE/S CREST THE RIDGE AND MOVE
THROUGH THE GREAT LAKES REGION. THE FIRST OF WHICH MOVES INTO THE
AREA ON SATURDAY. THE SECOND AND MORE SUBSTANTIAL WAVE DIGS INTO THE
GREAT LAKES REGION SUNDAY INTO MONDAY.
AT THE SURFACE RIDGING WILL BE IN PLACE FRIDAY NIGHT AND BRING DRY
WEATHER. THE HIGH SLIPS EAST QUICKLY ON SATURDAY WHICH SHOULD ALLOW
CHANCES FOR SHOWERS AND STORMS DURING THE AFTERNOON AHEAD OF THE
UPPER SHORTWAVE. THE CHANCES WILL CONTINUE INTO SATURDAY NIGHT AS A
WAVE OF LOW PRESSURE SLIDES THROUGH THE AREA AT THE SURFACE.
SUNDAY INTO MONDAY CHANCES FOR SHOWERS AND STORMS WILL CONTINUE AS
THE SECOND MORE POTENT UPPER TROUGH DIGS INTO THE GREAT LAKES.
SURFACE FEATURES ARE BIT MORE HARD TO DISCERN IN THIS TIME FRAME AS
THE GFS IS FURTHER NORTH AND DEEPER WITH THE SURFACE WAVE. FOLLOWED
THE GFS CLOSER HERE AS IT MAKES MORE SENSE TO HAVE A DEEPER FARTHER
NORTH WAVE GIVEN THE UPPER PATTERN. WE LOOK TO DRY OUT MONDAY NIGHT
INTO TUESDAY AS HIGH PRESSURE BUILDS IN.
TEMPERATURES THROUGH THE PERIOD SHOULD BE SEASONABLE DESPITE THE
RIDGING DAMPENING OUT. HEIGHTS ARE STILL FAIRLY HIGH AND 850MB TEMPS
ARE FORECAST TO BE IN THE TEENS C. HIGHS SHOULD BE IN THE UPPER 70S
TO AROUND 80 EACH DAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY)
ISSUED AT 100 PM EDT WED JUN 12 2013
VFR CONDITIONS SHOULD CONTINUE AT ALL THE TERMINALS THIS AFTERNOON
WITH FAIRLY EXTENSIVE MID CLOUD COVER AND A FEW SHOWERS.
PRIMARY AVIATION CONCERN IS ON SEVERE THUNDERSTORMS THAT WILL LIKELY
IMPACT KAZO... KBTL AND KJXN DURING THE MID TO LATE EVENING HOURS. A
FAST MOVING COMPLEX OF SEVERE STORMS IS LIKELY TO IMPACT THESE
TERMINALS FROM 01Z THROUGH 06Z WITH POTENTIAL FOR VERY SIGNIFICANT
WIND GUSTS IN ADDITION TO FREQUENT LIGHTNING... HEAVY RAIN AND HAIL.
NORTHERLY WINDS WILL DEVELOP TONIGHT IN THE WAKE OF THE STORMS WITH
MVFR CEILINGS AND POSSIBLY VSBY/S (FOG) DEVELOPING.
&&
.MARINE...
ISSUED AT 330 AM EDT WED JUN 12 2013
FAIRLY LIGHT WINDS WILL CONTINUE OVER THE LAKE RESULTING IN LOW WAVE
HEIGHTS. PATCHY DENSE FOG IS POSSIBLE DUE TO HIGH DEWPOINTS OVER THE
COLDER WATER SFC. NORTH WINDS WILL DEVELOP THURSDAY AND A SMALL
CRAFT ADVISORY MAY BE NEEDED.
&&
.HYDROLOGY...
ISSUED AT 330 AM EDT WED JUN 12 2013
THE MAIN PERIOD OF CONCERN IS THIS AFTERNOON AND EVENING. HEAVY
RAINFALL WILL BE POSSIBLE ACROSS THE SRN HALF OF THE CWA DURING THIS
TIME. AN INCH TO TWO INCHES SEEMS PLAUSIBLE ESPECIALLY SOUTH OF
I-94. THIS MAY LEAD TO LOCALIZED FLOODING.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&
$$
UPDATE...WDM
SYNOPSIS...93
SHORT TERM...93
LONG TERM...DUKE
AVIATION...LAURENS
HYDROLOGY...93
MARINE...93
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1209 PM EDT WED JUN 12 2013
LATEST UPDATE...
UPDATE
.SYNOPSIS...
ISSUED AT 330 AM EDT WED JUN 12 2013
AS LOW PRESSURE MOVES EAST FROM THE PLAINS TOWARD NORTHERN INDIANA
TODAY SHOWERS AND THUNDERSTORMS WILL DEVELOP. SOME OF THE STORMS
COULD BE STRONG TO SEVERE ESPECIALLY SOUTH OF I-94 WITH HIGH WINDS
THE MAIN THREAT. HEAVY RAIN WILL BE POSSIBLE THIS AFTERNOON AND
EVENING TOO SOUTH OF I-96. QUIETER WEATHER WILL RETURN THURSDAY
THROUGH SATURDAY AS THE LOW MOVES EAST AND NORTH WINDS ADVECT DRIER
AIR INTO LOWER MICHIGAN.
&&
.UPDATE...
ISSUED AT 1209 PM EDT WED JUN 12 2013
WE ADDED SEVERE WEATHER TO OUR GRIDS TO MATCH THE THIRTY PERCENT
AREA OF THE LATEST SPC OUTLOOK. WE DID THIS FROM 5PM TO 11PM
BECAUSE THE SPC MODELS WERE SHOWING THE HIGHEST PROBABILITY DURING
THAT TIME FRAME.
AN AREA OF SHOWERS OVER EASTERN WISCONSIN TO SOUTHERN LAKE MICHIGAN
IS MOVING INTO THE CWA OVER THE NEXT FEW HOURS. IN SPITE OF THE
INCREASING INSTABILITY WE DO NOT EXPECT STRONG THUNDERSTORM
DEVELOPMENT AS THERE IS TOO MUCH CONVECTIVE INHIBITION AND MID
LEVEL DRY AIR.
UPDATE ISSUED AT 1043 AM EDT WED JUN 12 2013
MY CURRENT THINKING IS THE BEST THREAT FOR SEVERE STORMS WILL BE
THIS EVENING INTO EARLY TONIGHT. THE DENSE MID AND HIGH CLOUD
COVER OVER MN/WI/LWR MI WILL CAUSE THE BEST DESTABILIZATION TO BE
WELL SOUTH OF OUR AREA THIS AFTERNOON. SO... THE STRONGEST
THUNDERSTORMS WILL BE ASSOCIATED WITH THE MAIN UPPER LEVEL WAVE
MOVING THROUGH THIS EVENING. THIS IDEA IS SUPPORTED BY THE LATEST
12Z NAM...12Z HRRR...00Z SPC WRF...12 RAP MODELS.
THE BEST FORCING (MOISTURE TRANSPORT VECTORS 1000/850...LOW LEVEL
JET AND THERMAL GRADIENT...HIGHEST MIXED LAYER CAPE) ARE ALL WELL
SOUTH OF INTERSTATE 94 AND ACTUALLY NEAR AND SOUTH OF INTERSTATE
80 AS THE UPPER WAVE MOVES THROUGH EARLY TONIGHT. WE SHOULD SEE
SOME CONVECTION OVER OUR SRN ONE OR TWO ROWS OF COUNTIES MID
EVENING AS THE WAVE MOVES IN. DEFORMATION ZONE RAIN WILL FOLLOW
DURING THE OVERNIGHT HOURS. THE HEAVIEST OF THAT WILL BE NEAR AND
SOUTH OF INTERSTATE 94.
THERE IS A CONVECTIVE COMPLEX OVER E CNTL MN AT 10 AM HEADING
EAST. THAT IS ON THE TAIL OF THE PV MAX ASSOCIATED WITH THE
CONVECTION THAT CROSSED MN AND WI EARLIER AND HAS SINCE DIED. THAT
PV MAX MOVES THROUGH OUR CNTL CWA THIS AFTERNOON. I BELIEVE THAT
WILL BE THE FOCUS FOR OUR AFTERNOON CONVECTION. THE INSTABILITY IS
MARGINAL (LOOKING AT RAP SOUNDING THIS AFTERNOON) FOR THIS
CONVECTION SO I DO NOT BELIEVE THIS WILL BE SEVERE... MOSTLY JUST
GENERIC THUNDERSTORMS.
&&
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 330 AM EDT WED JUN 12 2013
FORECAST CONCERNS DEAL WITH CONVECTIVE TRENDS THIS MORNING THROUGH
THIS EVENING.
LATEST REGIONAL RADAR SHOWS THAT STORMS HAVE FIRED AS EXPECTED IN
NORTHEAST NEBRASKA ON THE NOSE OF A STRONG LLJ. THESE STORMS HAVE
MOVED INTO NW IOWA. A BIT FARTHER NORTH OVER SOUTH DAKOTA ANOTHER
AREA OF STORMS IS MOVE EWD. THESE ARE ASSOCIATED WITH A SHORT WAVE
MOVING ACROSS THE NRN PLAINS. SHORT RANGE MODELS MOVE THIS SHORT
WAVE SEWD TOWARD CHICAGO BY THIS AFTERNOON AT THE SAME TIME THE SFC
LOW IN SRN NEBRASKA IS MOVING ENEWD. HRRR SHOWS BOTH CLUSTERS OF
STORMS WEAKENING AS THEY MOVE EAST WITH THE IOWA CONVECTION MOVING
TO THE WRN CWA BY NOON OR SO AS MOSTLY SHOWERS.
CONVECTION REDEVELOPS OVER NW IOWA BY EARLY AFTERNOON AS STRONG
DYNAMICS TAKE SHAPE. SBCAPE AROUND 3K J/KG COUPLED WITH STRONG
MOISTURE CONVERGENCE...60-70KTS BULK SHEAR AND LIFT FROM THE
APPROACHING SHORT WAVE SHOULD RESULT IN STRONG TO SEVERE STORMS
DEVELOPING OVER ILLINOIS AND MOVING ESE TOWARD THE SRN CWA. A 50KT
MID LEVEL JET WILL PUSH THE STORMS EWD...PERHAPS AS A DERECHO. CAN/T
ARGUE TOO MUCH WITH THE POSITION OF THE DAY ONE SLIGHT AND MODERATE
RISK AREAS. THIS ISN/T A SLAM DUNK BY ANY MEANS BUT THE HIGHEST
THREAT FOR STRONG/SVR STORMS WILL BE SOUTH OF A MUSKEGON TO LANSING
LINE. LATEST NAM ALSO PUSHES THE WARM FRONT INTO THE SRN CWA THIS
AFTERNOON. SO...WITH THE WARM FRONT IN PLACE WE CAN/T RULE OUT A
TORNADO EITHER.
THE SVR THREAT WILL END THIS EVENING AS THE LOW MOVES BY TO THE
SOUTH AND QUIETER WEATHER WILL RETURN THURSDAY AND FRIDAY.
.LONG TERM...(FRIDAY NIGHT THROUGH TUESDAY)
ISSUED AT 330 AM EDT WED JUN 12 2013
UPPER RIDGING WILL EXTEND FROM THE GULF COAST NORTH INTO THE UPPER
MID WEST FRIDAY NIGHT. THE RIDGING WILL BE FLATTENED THROUGH THE
LONG TERM AS A SERIES OF SHORTWAVE/S CREST THE RIDGE AND MOVE
THROUGH THE GREAT LAKES REGION. THE FIRST OF WHICH MOVES INTO THE
AREA ON SATURDAY. THE SECOND AND MORE SUBSTANTIAL WAVE DIGS INTO THE
GREAT LAKES REGION SUNDAY INTO MONDAY.
AT THE SURFACE RIDGING WILL BE IN PLACE FRIDAY NIGHT AND BRING DRY
WEATHER. THE HIGH SLIPS EAST QUICKLY ON SATURDAY WHICH SHOULD ALLOW
CHANCES FOR SHOWERS AND STORMS DURING THE AFTERNOON AHEAD OF THE
UPPER SHORTWAVE. THE CHANCES WILL CONTINUE INTO SATURDAY NIGHT AS A
WAVE OF LOW PRESSURE SLIDES THROUGH THE AREA AT THE SURFACE.
SUNDAY INTO MONDAY CHANCES FOR SHOWERS AND STORMS WILL CONTINUE AS
THE SECOND MORE POTENT UPPER TROUGH DIGS INTO THE GREAT LAKES.
SURFACE FEATURES ARE BIT MORE HARD TO DISCERN IN THIS TIME FRAME AS
THE GFS IS FURTHER NORTH AND DEEPER WITH THE SURFACE WAVE. FOLLOWED
THE GFS CLOSER HERE AS IT MAKES MORE SENSE TO HAVE A DEEPER FARTHER
NORTH WAVE GIVEN THE UPPER PATTERN. WE LOOK TO DRY OUT MONDAY NIGHT
INTO TUESDAY AS HIGH PRESSURE BUILDS IN.
TEMPERATURES THROUGH THE PERIOD SHOULD BE SEASONABLE DESPITE THE
RIDGING DAMPENING OUT. HEIGHTS ARE STILL FAIRLY HIGH AND 850MB TEMPS
ARE FORECAST TO BE IN THE TEENS C. HIGHS SHOULD BE IN THE UPPER 70S
TO AROUND 80 EACH DAY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 747 AM EDT WED JUN 12 2013
MAIN CONCERN TODAY WILL BE THUNDERSTORM EVOLUTION...COVERAGE AND
SEVERITY. VFR CEILINGS ARE IN PLACE AT DAYBREAK...WITH SOME MVFR
VSBY/S IN FOG. THE EXPECTATION IS THE FOG WILL LIFT THIS
MORNING...GIVING WAY TO VFR CONDITIONS BY LATE MORNING. SOME
SCATTERED SHOWERS ARE EXPECTED THROUGH THE MORNING...BUT MOST WILL
BE LIGHT AND NOT IMPACT CONDITIONS MUCH.
THE FOCUS THIS AFTERNOON AND EVENING IS ON THUNDERSTORMS. A COUPLE
SCENARIOS ARE IN PLAY WITH STORMS SWEEPING IN OFF OF LAKE MICHIGAN
AS EARLY AS NOON TO 100PM. THEY WOULD MOVE THROUGH THE TAF SITES
THIS AFTERNOON WITH THE POTENTIAL FOR SIGNIFICANT WIND
GUSTS...OVER 50 KNOTS. A SECOND SCENARIO WOULD HAVE THE STORMS SWEEP
IN LATER THIS EVENING WITH A MAINLY DRY AFTERNOON. BOTH SCENARIOS
WILL HAVE SIGNIFICANT WIND POTENTIAL AS WELL AS HAIL. ANY STORMS
THAT DEVELOP TODAY COULD BE SEVERE. NORTHERLY WINDS WILL DEVELOP
TONIGHT IN THE WAKE OF THE STORMS WITH MVFR CEILINGS AND POSSIBLY
VSBY/S (FOG) DEVELOPING.
USED VCTS IS THIS MORNING/S TAFS GIVEN THE UNCERTAINTY. LATER
UPDATES WILL PROVIDE GREATER DETAIL.
&&
.MARINE...
ISSUED AT 330 AM EDT WED JUN 12 2013
FAIRLY LIGHT WINDS WILL CONTINUE OVER THE LAKE RESULTING IN LOW WAVE
HEIGHTS. PATCHY DENSE FOG IS POSSIBLE DUE TO HIGH DEWPOINTS OVER THE
COLDER WATER SFC. NORTH WINDS WILL DEVELOP THURSDAY AND A SMALL
CRAFT ADVISORY MAY BE NEEDED.
&&
.HYDROLOGY...
ISSUED AT 330 AM EDT WED JUN 12 2013
THE MAIN PERIOD OF CONCERN IS THIS AFTERNOON AND EVENING. HEAVY
RAINFALL WILL BE POSSIBLE ACROSS THE SRN HALF OF THE CWA DURING THIS
TIME. AN INCH TO TWO INCHES SEEMS PLAUSIBLE ESPECIALLY SOUTH OF
I-94. THIS MAY LEAD TO LOCALIZED FLOODING.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&
$$
UPDATE...WDM
SYNOPSIS...93
SHORT TERM...93
LONG TERM...DUKE
AVIATION...DUKE
HYDROLOGY...93
MARINE...93
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
300 PM CDT WED JUN 12 2013
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 259 PM CDT WED JUN 12 2013
AFTER TSTMS EXIT THE AREA THIS EVENING...WEATHER WILL BE MUCH
QUIETER...AND DRIER ON THU. AN UPPER LEVEL FEATURE SPINNING IN NE
SD IS RESPONSIBLE FOR TSTMS ACROSS S MN. CLUSTERS OF STORMS
CONTINUE TO DEVELOP JUST AHEAD OF THE UPPER FEATURE IN SW/SC
MN...WITH INDIVIDUAL CELLS MOVING NE WHILE THE SYSTEM AS A WHOLE
SHIFTS SE. SO FAR TODAY...THE BIGGEST THREAT IN OUR AREA HAS BEEN
HEAVY RAIN AND LOCALIZED FLOODING AS SEVERAL LOCATIONS HAVE
RECEIVED 3+ INCHES OF RAIN. THE PROSPECTS OF ADDITIONAL SEVERE WX
ACROSS S MN/W WI IS LOW DUE TO THE BULK OF THE DYNAMICS/
INSTABILITY FOCUSED ALONG THE FRONT TO OUR S AND E...BUT ANY
ISOLATED SEVERE WX WE DO GET SHOULD BE OF THE WIND VARIETY. THE
LAST OF THE -SHRA/TS SHOULD EXIT MPX CWA BY 02Z...WITH CLEARING
RAPIDLY MOVING IN FROM N TO S. HIGH PRESSURE IN THE WESTERN
DAKOTAS WILL SHIFT INTO W MN LATE TONIGHT...BUT WITH A SLOWLY
MOVING LOW HEADING INTO THE GREAT LAKES...THERE SHOULD BE ENOUGH
OF A GRADIENT TO PRECLUDE WIDESPREAD FOG FORMATION. WITH THAT
BEING SAID...WE DID INCLUDED PATCHY FOG ALONG THE MN RIVER VALLEY
AND WHERE SOME OF THE HEAVIEST RAIN FELL EARLIER TODAY. THURSDAY
SHOULD FEATURE PLENTY OF SUNSHINE AND TEMPS VERY NEAR AVERAGE.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 259 PM CDT WED JUN 12 2013
HIGH PRESSURE/DRY WEATHER ACROSS THE REGION THURSDAY NIGHT WILL
GIVE WAY TO INCREASING SE FLOW ON FRIDAY AS A COLD FRONT
APPROACHES FROM THE NORTHERN PLAINS. SHOWERS AND A FEW
THUNDERSTORMS ARE EXPECTED TO DEVELOP ACROSS WESTERN MN FRIDAY
MORNING AND SPREAD INTO EASTERN MN AND WEST CENTRAL WI BY FRIDAY
EVENING. THERE IS GOOD CONSENSUS WITHIN THE VARIOUS MODEL SOLUTIONS
THAT AN AREA OF LOW PRESSURE... ON THE TAIL END OF THE FRONT... WILL
MOVE EITHER ACROSS SOUTHERN MN OR JUST TO THE SOUTH OF THE STATE FRIDAY
NIGHT. THIS WILL NOT ONLY BE THE FOCUS FOR SEVERE WEATHER BUT
PERHAPS ANOTHER HEAVY RAIN EVENT. THE LOW LEVEL MOISTURE TRANSPORT
IS AIMED AT FAR SOUTHERN MN LATE IN THE DAY ON FRIDAY AND INCREASES
DURING THE EVENING AS THE LOW LEVEL JET STRENGTHENS. FORECAST PW
VALUES ARE NOT QUITE AS HIGH AS THIS MORNING...BUT STILL NEARLY
1.75 INCHES... OR ABOUT 160 PERCENT OF NORMAL. THIS IS RIGHT AROUND 2
STANDARD DEVIATIONS ABOVE NORMAL. HENCE...HIGH POPS REMAIN IN PLAY
FOR FRIDAY NIGHT ACROSS THE FA.
THE NAM IS THE ONLY SOLUTION THAT DRIES THE CWA EARLY ON SATURDAY
AS IT PUSHES THE FRONT EAST AND SOUTH OF THE FA. THE GEM/GFS/ECMWF
KEEP THE BOUNDARY NEAR THE MN/WI BORDER ON SOUTHWEST WITH SOME
SHOWERS AND THUNDERSTORMS POSSIBLE. THE FORECAST REFLECTS THE
LATTER SOLUTIONS WITH SMALL POPS HELD ON TO FOR SATURDAY/SATURDAY
NIGHT. A SLIGHT CHANCE FOR SHOWERS CONTINUES ON SUNDAY AS A RATHER
STRONG SHORT WAVE BEGINS TO DROP IN FROM SOUTH CENTRAL CANADA. ITS
QUITE POSSIBLE MUCH OF THE DAY MAY BE DRY WITH SHOWERS/ISOLATED
THUNDERSTORMS HOLDING OFF UNTIL THE EVENING AND OVERNIGHT HOURS.
THIS FEATURE WILL MOVE ON MONDAY WITH THE SHOWERS DIMINISHING
FROM NW TO SE THROUGH THE DAY.
WE ARE STILL LOOKING AT THE POTENTIAL FOR UPPER LEVEL RIDGING TO
BUILD OVER THE NORTHERN PLAINS AND THE UPPER MISSISSIPPI VALLEY
REGION FOR TUESDAY AND WEDNESDAY WITH PERHAPS A FEW DAYS OF DRY
WEATHER BACK TO BACK. THE PATTERN DOES NOT HOLD LONG AS MORE UPPER
LEVEL TROUGHING IS INDICATED TO MOVE INTO THE FA FOR THE END OF
NEXT WEEK ALONG WITH MORE SHOWERS AND THUNDERSTORMS. AFTER A COOL
START WITH HIGHS/LOWS THURSDAY AND FRIDAY...READINGS FROM SATURDAY
THROUGH NEXT WEDNESDAY LOOK TO BE AT OR ABOVE SEASONAL LEVELS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1223 PM CDT WED JUN 12 2013
SCATTERED CONVECTION IS ONGOING ACROSS THE ENTIRE AREA
OUT AHEAD OF AN UPPER LOW CURRENTLY IN NE SD. AS THIS LOW MOVES
ACROSS SOUTH CENTRAL MN THIS EVENING...STORMS WILL SHIFT SE...WITH
ALL TAF SITES FREE OF PRECIP BY 02Z. THE HI-RES HRRR MODEL SEEMS TO
HAVE A PRETTY GOOD HANDLE ON THE CURRENT SITUATION AND RELIED PRETTY
HEAVILY ON ITS DEPICTION OF TSRA ACROSS THE TAF SITES. IF/WHEN A
TSTMS MOVES OVER A SITE...EXPECT THE VIS TO DIP TO 1-3SM WITH +RA AND
THE POSSIBILITY OF WIND GUSTS TO 40KTS (DIRECTION BEING FAIRLY
VARIABLE WITH AN EMPHASIS ON N-E). AFTER CONVECTION MOVES OUT OF THE
AREA...WE SHOULD BE LEFT WITH A SMATTERING OF MID/HIGH CLOUDS FOR AT
LEAST THE FIRST HALF OF THE NIGHT ALONG WITH A NORTHERLY GRADIENT OF
5-10KTS. CLEARING SKIES LATER IN THE NIGHT AND A SLACKENING WIND IN
THE WEST AS HIGH PRESSURE SETTLES IN COULD LEAD TO FOG FORMATION
CONSIDERING ALL THE RAIN TODAY. WITH UNCERTAINTIES REGARDING EXTENT
OF HIGH CLOUDS AND WIND...HAVE ONLY INCLUDED FOG MENTION AT
KRWF...BUT THE POTENTIAL EXISTS FOR MOST SITES.
MSP...BAND OF STEADY -RA WILL BE NE OF THE AIRFIELD AT THE BEGINNING
OF THE PD...BUT SCT TSRA BACK TO THE SW WILL OCCASIONALLY IMPACT THE
AIRFIELD...MOST LIKELY BETWEEN 19-22Z. THE MAIN THREATS WILL BE
HEAVY RA AND POSSIBLY ERRATIC WIND GUSTS TO 35KTS. THE CONVECTIVE
THREAT SHOULD BE OVER BY 00Z WITH VFR PREVAILING. THERE IS A CHANCE
FOR A LITTLE FOG AROUND DAYBREAK THANKS TO THE SATURATED
GROUND...BUT THERE SHOULD BE ENOUGH OF A GRADIENT TO PRECLUDE ANY
LONG-LIVED VSBY RESTRICTIONS.
/OUTLOOK FOR KMSP/
THU NGT...VFR. E WIND 5 KTS.
FRI...VFR. SE WIND 10-20KTS.
FRI NGT...MVFR POSSIBLE. TSRA POSSIBLE. S BCMG W 10KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
SHORT TERM...JCA
LONG TERM...RAH
AVIATION...JCA
AREA FORECAST DISCUSSION...UPDATED
NWS TWIN CITIES/CHANHASSEN MN
1225 PM CDT WED JUN 12 2013
UPDATED FOR AVIATION DISCUSSION BELOW
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 333 AM CDT WED JUN 12 2013
ELEVATED CONVECTION SCATTERED ABOUT MUCH OF THE CWA THIS MORNING.
STEEP MID LEVEL LAPSE RATES AND AMPLE SHEAR FOR AT LEAST SOME
SMALL HAIL IN STRONGER STORMS. HIRES MODELS INDICATE SOME FORM OF
THUNDERSTORM COMPLEX WILL DEVELOP OVER FAR SOUTHERN MN EARLY THIS
MORNING....WITH PERHAPS REMNANTS OF THE CENTRAL DAKOTAS SYSTEM
MOVING INTO THE SOUTH LATER THIS MORNING AND EXITING TO THE
SOUTHEAST BY THIS EVENING. ATMOSPHERE REMAINS HIGHLY CAPPED OVER
THE FAR SOUTH...WITH HIGH CONVECTIVE INHIBITION NOTED. IF COMPLEX
DOES BECOME STRONG ENOUGH...COULD SEE SOME STRONG WINDS DEVELOP
WITH THE SYSTEM. DETERMINISTIC MODELS CONTINUE TO SHOW ACTIVITY
MOVING EAST SOUTHEAST AND OUT OF THE CWA BY 00Z THU. WILL CONTINUE
THIS TREND AS WELL...BEST INSTABILITY AND FORCING IS DRIVEN
SOUTHEAST OF THE AREA AT THAT TIME.
DRIER CONDITIONS WITH A CLEARING SKY EXPECTED FOR TONIGHT. GRADIENT
WINDS MAY BE STRONG ENOUGH TO PRECLUDE SIGNIFICANT FOG FORMATION
OVER THE WEST. THE SURFACE HIGH BUILDS INTO THAT REGION BY 12Z THU.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 333 AM CDT WED JUN 12 2013
THE EXTENDED RANGES OF THE FORECAST PERIOD WILL BE LITTERED WITH
OCCASIONAL SHOWER AND THUNDERSTORM CHANCES AS THE LARGE SCALE
PATTERN ALOFT REMAINS ACTIVE.
THURSDAY SHOULD BE DRY HOWEVER...AS MID LEVEL RIDGING PREVAILS
INTO THE UPPER MIDWEST. TEMPERATURES SHOULD BE NEAR SEASONAL
NORMALS...WITH HIGHS MOSTLY IN THE MID TO UPPER 70S.
THE DRY STINT WILL END ON FRIDAY...AS SOUTHERLY FLOW /MOISTURE
TRANSPORT/ ENSUES AHEAD OF AN APPROACHING NORTHERN ROCKIES UPPER
TROUGH. SHOULD SEE SHOWERS AND THUNDERSTORMS PUSHING FROM WEST TO
EAST ACROSS MN ON FRIDAY...WITH MORE WIDESPREAD ACTIVITY EXPECTED
ON FRIDAY NIGHT INTO SATURDAY AS DEPICTED BY PROGGED 305-310K
ISENTROPIC LIFT AND MOISTURE. WITH DECENT AGREEMENT AND CONSISTENCY
AMONGST THE GFS/ECMWF/NAM/ETC AND THEIR ILLUSTRATIONS OF THE
SURFACE TROUGH NOSING INTO SOUTHWEST MN ON FRIDAY NIGHT...LIKELY
POPS SEEM WARRANTED.
LESS CONFIDENT ON WIDESPREAD ACTIVITY ON SATURDAY...WITH THE UPPER
TROUGH EXPECTED TO HAVE LIFTED INTO SASKATCHEWAN...AND THE COLD
FRONT HAVING PASSED ACROSS AT LEAST A DECENT PORTION OF THE CWA.
THEREFORE...HAVE LIMITED CHANCE POPS TO THE SOUTHEASTERN PORTION
OF THE FORECAST AREA /SOUTH CENTRAL MN NORTHEAST ACROSS WEST
CENTRAL WI/. SATURDAY COULD END UP BEING A DRY DAY FOR A LARGE
PART OF THE AREA DEPENDING ON HOW QUICKLY THE FRONT PASSES.
THE AFOREMENTIONED UPPER LOW OPENS UP AND DROPS SOUTHEAST FROM
SASKATCHEWAN/MANITOBA ON SUNDAY INTO MONDAY. CONFIDENCE ON THE
STRENGTH/TIMING/MOISTURE IS LOW...SO POPS IN THE SUNDAY-MONDAY TIME FRAME
ARE IN THE 15-30 PERCENT RANGE.
AFTER THE WAVE DROPS ACROSS THE AREA...MID LEVEL RIDGING BUILDS
BACK INTO THE NORTH CENTRAL CONUS...WITH A DRYING AND WARMING TREND
EXPECTED INTO THE MIDDLE OF NEXT WEEK. HIGHS ATTENDANT WITH THE
ANTICIPATED PATTERN WOULD BE MORE SOLIDLY IN THE 80S.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1223 PM CDT WED JUN 12 2013
SCATTERED CONVECTION IS ONGOING ACROSS THE ENTIRE AREA
OUT AHEAD OF AN UPPER LOW CURRENTLY IN NE SD. AS THIS LOW MOVES
ACROSS SOUTH CENTRAL MN THIS EVENING...STORMS WILL SHIFT SE...WITH
ALL TAF SITES FREE OF PRECIP BY 02Z. THE HI-RES HRRR MODEL SEEMS TO
HAVE A PRETTY GOOD HANDLE ON THE CURRENT SITUATION AND RELIED PRETTY
HEAVILY ON ITS DEPICTION OF TSRA ACROSS THE TAF SITES. IF/WHEN A
TSTMS MOVES OVER A SITE...EXPECT THE VIS TO DIP TO 1-3SM WITH +RA AND
THE POSSIBILITY OF WIND GUSTS TO 40KTS (DIRECTION BEING FAIRLY
VARIABLE WITH AN EMPHASIS ON N-E). AFTER CONVECTION MOVES OUT OF THE
AREA...WE SHOULD BE LEFT WITH A SMATTERING OF MID/HIGH CLOUDS FOR AT
LEAST THE FIRST HALF OF THE NIGHT ALONG WITH A NORTHERLY GRADIENT OF
5-10KTS. CLEARING SKIES LATER IN THE NIGHT AND A SLACKENING WIND IN
THE WEST AS HIGH PRESSURE SETTLES IN COULD LEAD TO FOG FORMATION
CONSIDERING ALL THE RAIN TODAY. WITH UNCERTAINTIES REGARDING EXTENT
OF HIGH CLOUDS AND WIND...HAVE ONLY INCLUDED FOG MENTION AT
KRWF...BUT THE POTENTIAL EXISTS FOR MOST SITES.
MSP...BAND OF STEADY -RA WILL BE NE OF THE AIRFIELD AT THE BEGINNING
OF THE PD...BUT SCT TSRA BACK TO THE SW WILL OCCASIONALLY IMPACT THE
AIRFIELD...MOST LIKELY BETWEEN 19-22Z. THE MAIN THREATS WILL BE
HEAVY RA AND POSSIBLY ERRATIC WIND GUSTS TO 35KTS. THE CONVECTIVE
THREAT SHOULD BE OVER BY 00Z WITH VFR PREVAILING. THERE IS A CHANCE
FOR A LITTLE FOG AROUND DAYBREAK THANKS TO THE SATURATED
GROUND...BUT THERE SHOULD BE ENOUGH OF A GRADIENT TO PRECLUDE ANY
LONG-LIVED VSBY RESTRICTIONS.
/OUTLOOK FOR KMSP/
THU NGT...VFR. E WIND 5 KTS.
FRI...VFR. SE WIND 10-20KTS.
FRI NGT...MVFR POSSIBLE. TSRA POSSIBLE. S BCMG W 10KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
SHORT TERM...DWE
LONG TERM...LS
AVIATION...JCA
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
1258 PM CDT WED JUN 12 2013
.SHORT TERM...(THROUGH LATE THIS AFTERNOON)
ISSUED AT 337 AM CDT WED JUN 12 2013
MAIN CONCERN DEALS WITH POTENTIAL FOR SEVERE WEATHER THIS AFTERNOON
INTO THE EVENING HOURS OVER PARTS OF THE CWA IF THUNDERSTORMS ARE
ABLE TO DEVELOP. IF THUNDERSTORMS DO DEVELOP...THEN THEY WILL
LIKELY BE SEVERE...PARTICULARLY OVER NORTHEAST MISSOURI INTO CENTRAL
ILLINOIS WITH DAMAGING WIND GUSTS IN EXCESS OF 70 MPH...LARGE HAIL
AND ISOLATED TORNADOES.
EXPECT MAINLY DRY CONDITIONS THROUGH THE MORNING HOURS AS THE
THUNDERSTORM COMPLEX CURRENTLY OVER WESTERN IOWA STAYS NORTH OF THE
AREA PER THE RAP FORWARD PROPAGATION VECTORS. OBSERVED AND FORECAST
SOUNDINGS STILL SHOW A VERY PRONOUNCED WARM LAYER BETWEEN 900-650MB
THROUGH LATE AFTERNOON WHICH SHOULD LIMIT THUNDERSTORM DEVELOPMENT.
THEREAFTER...THE TAIL END OF THE TROUGH CURRENTLY OVER THE HIGH
PLAINS WILL REACH THE MISSISSIPPI RIVER WHICH WILL ACT TO WEAKEN
THIS WARM LAYER AS THE ATTENDANT COLD FRONT MOVES SOUTHEAST ACROSS
THE CWA. MOST MODEL SOUNDINGS STILL SHOW SOME CONVECTIVE INHIBITION
OR VERY NARROW POSITIVE CAPE UP TO 700MB WHICH MAY KEEP
THUNDERSTORMS NORTH AND EAST OF THE AREA. WITH THIS SAID...MID
LEVEL FORCING AND LOW LEVEL MOISTURE CONVERGENCE IS WORTH KEEPING
SCATTERED THUNDERSTORMS IN THE FORECAST LATE THIS AFTERNOON INTO THE
EVENING AS THE COLD FRONT MOVES ACROSS THE CWA. INSTABILITY AND
SHEAR PARAMETERS FAVOR SEVERE THUNDERSTORMS WITH LATE AFTERNOON
MLCAPES AROUND 3000 J/KG AND 0-6KM SHEAR OF 40-50KTS. RELATIVELY
DRY AIR BELOW 700MB FAVORS THE POTENTIAL FOR DAMAGING WINDS
GUSTS...AND THERE IS A LARGE AMOUNT OF CAPE BETWEEN -10 AND -30C
WHICH SUGGESTS THE POTENTIAL FOR LARGE HAIL. SHEAR IS LINEAR IN THE
LOWEST LEVELS...THOUGH 0-1KM SHEAR NEAR 25KTS SUGGESTS TORNADOES ARE
ALSO POSSIBLE.
DID NOT CHANGE FORECAST HIGHS TODAY AS CURRENT TEMPERATURES ARE IN
THE 70S AND THERE WILL BE DECENT MIXING UP TO 850MB TODAY WITH MORE
SUN THAN YESTERDAY.
BRITT
.LONG TERM...(TONIGHT THROUGH TUESDAY)
ISSUED AT 337 AM CDT WED JUN 12 2013
AFTERNOON/EVENING CONVECTION SHOULD BE EXITING THE AREA BY 06Z.
CANNOT RULE OUT A STRAY SHOWER OR STORM OUT AHEAD OF OR RIGHT ON THE
COLD FRONT AS IT PUSHES THROUGH EAST CENTRAL AND SOUTHEAST MISSOURI
AND SOUTHERN ILLINOIS. NORTHWEST FLOW WILL BRING COOLER AND DRIER
AIR WITH SURFACE DEWPOINTS DROPPING BACK INTO THE UPPER 50S AND
LOWER 60S. 850MB TEMPS ALSO DROP INTO THE LOW TO MID TEENS BEHIND
THE FRONT. MODELS HAVE BEEN CONSISTENTLY AMPLIFYING THE FLOW
THURSDAY INTO FRIDAY WITH A FULL LONGWAVE TROF OVER THE EAST COAST
AND THE UPPER LEVEL RIDGE BUILDING ACROSS THE GREAT PLAINS INTO THE
UPPER MIDWEST. THIS SHOULD KEEP THE LOW LEVEL RIDGE LOCKED IN
ACROSS THE MISSISSIPPI VALLEY AT LEAST THROUGH FRIDAY. SEASONABLY
COOL GUIDANCE TEMPS LOOK PRETTY REASONABLE WITH AFOREMENTIONED COOL
AND DRY RIDGE IN PLACE. THERE IS A SMALL CHANCE THAT INCREASING
WARM ADVECTION ON THE WESTERN PERIPHERY OF THE LOW LEVEL RIDGE MAY
PRODUCE ISOLATED SHOWERS OR STORMS FRIDAY OVER PARTS OF CENTRAL AND
NORTHEAST MISSOURI SO HAVE SOME SLIGHT CHANCE POPS IN THOSE AREAS.
THE WEEKEND IS LOOKING MORE AND MORE STORMY AS THE UPPER LEVEL RIDGE
BREAKS DOWN IN RESPONSE TO A SHORTWAVE WHICH IS PULLED NORTHEAST OUT
OF THE GULF OF MEXICO. THIS WAVE IS LIKELY TO HAVE QUITE A BIT OF
MOISTURE ASSOCIATED WITH IT. AM UNSURE WHAT THE POTENTIAL FOR
SEVERE WEATHER WILL BE AT THIS TIME...BUT IT DOES LOOK LIKE THERE
WILL BE THUNDERSTORMS ON AND OFF FROM SATURDAY AFTERNOON AT LEAST
THROUGH SUNDAY NIGHT OR MONDAY AND SOME LOCALLY HEAVY RAIN MAY BE
POSSIBLE. TUESDAY LOOKS DRIER AS THE WAVE MOVES EAST AND WEAK
RIDGING BUILDS BACK ACROSS THE MID MISSISSIPPI VALLEY. TEMPERATURES
THROUGH THE PERIOD LOOK TO BE NEAR NORMAL.
CARNEY
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1230 PM CDT WED JUN 12 2013
A COLD FRONT CURRENTLY EXTENDING FROM WESTERN IOWA SOUTHWESTWARD
THROUGH EAST CENTRAL KANSAS WILL MOVE THROUGH THE AREA THIS
FORECAST PERIOD. CURRENT THINKING IS THAT DRY VFR CONDITIONS WILL
PREVAIL AT AREA TAF SITES THROUGH THE PERIOD...WITH A POTENTIAL TO
DECREASE TO LOW-END MVFR DURING THE LATE OVERNIGHT AND EARLY
MORNING HOURS ON THURSDAY AFTER FROPA. THE MAIN UNCERTAINTY THIS
FORECAST PERIOD REVOLVES AROUND TSRA CHANCES...WITH KUIN
MAINTAINING HIGHEST PROBABILITY OF SEEING SHRA/TSRA DURING THE
LATE AFTERNOON AND EARLY EVENING. ANY STORMS THAT DEVELOP COULD
BECOME SEVERE...ACCOMPANIED BY DAMAGING WINDS AND LARGE HAIL.
HOWEVER...FEEL THAT MAIN FOCUS FOR STORMS REMAINS FURTHER NORTH
ACROSS IOWA...THUS HAVE MAINTAINED VCTS IN THE KUIN TAF GIVEN
UNCERTAINTIES DUE TO COVERAGE THAT FAR SOUTH. WHILE THERE IS A
CHANCE FOR SOME SHRA/TSRA ACTIVITY AHEAD OF THE FRONT...EXPECT
MAJORITY OF THE COVERAGE TO REMAIN NORTH AND EAST OF METRO AREA
TAF SITES AT THIS TIME. EXPECT FROPA TO OCCUR AROUND THE 06-07Z
TIME FRAME AT KCOU AND KUIN...AND 08-09Z FOR METRO TAF SITES.
OTHERWISE...GUSTY SOUTHWEST WINDS WILL CONTINUE THROUGH THE
REMAINDER OF THE AFTERNOON BEFORE THE GUSTS DIMINISH AFTER SUNSET.
WINDS WILL GRADUALLY VEER TO THE NORTHWEST BEHIND THE
FRONT...AND DESPITE THE WINDS REMAINING BETWEEN 10-12KT...DO NOT
EXPECT IT TO BE AS GUSTY ON THURSDAY.
SPECIFICS FOR KSTL...
DRY AND VFR CONDITIONS SHOULD PREVAIL FOR A MAJORITY OF THIS
FORECAST PERIOD. THERE EXISTS THE POTENTIAL FOR SOME SHRA/TSRA
ACTIVITY AHEAD OF AN ADVANCING COLD FRONT...THOUGH CONFIDENCE
REMAINS TOO LOW TO INCLUDE MENTION IN THE TAF. LOW-END MVFR
CONDITIONS ARE POSSIBLE IN THE WAKE OF THE FRONT DURING THE LATE
OVERNIGHT AND EARLY MORNING HOURS ON THURSDAY...HOWEVER...EXPECT
DRIER AIR TO FILTER IN BEHIND THE FRONT AND THUS NOT TOO SURE
WHETHER THE LOWER CIGS WILL REMAIN SCT OR GO BKN-OVC...THEREFORE
HAVE MAINTAINED TRENDS FOR KSTL AT THIS TIME. OTHERWISE...GUSTY
WINDS TODAY WILL DIMINISH AFTER SUNSET...AND THOUGH WINDS WILL
REMAIN AOA 12KT OVERNIGHT...DO NOT EXPECT IT TO BE AS GUSTY ON
THURSDAY IN THE WAKE OF THE FRONT.
JP
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS BILLINGS MT
312 PM MDT WED JUN 12 2013
.SHORT TERM...VALID FOR THU AND FRI...
OVERVIEW...A FETCH OF MOISTURE CONTINUES TO STREAM OVER OUR
FORECAST AREA. THIS IS DUE TO SW FLOW ALOFT TAPPING INTO PACIFIC
MOISTURE AHEAD OF AN APPROACHING LONG WAVE TROUGH ON THE PACIFIC
NW COAST. IN THE LOWER LEVELS EASTERLY FLOW CONTINUES AND HAS KEPT
HIGH DEWPOINTS OVER THE REGION.
SO WE HAVE THE MOISTURE AND EFFECTIVE SHEAR NECESSARY FOR STRONG
THUNDERSTORMS TODAY. RAP MODEL PROGGS INDICATE AN AXIS OF
INSTABILITY FROM THE FRONT RANGE OF NORTH CENTRAL MONTANA DOWN TO
SHERIDAN COUNTY IN WYOMING THIS AFTERNOON AND INTO THE EARLY
EVENING. THIS AXIS IS WHERE I EXPECT STORMS TO REALLY FIRE UP
WITH SUSTAINED UPDRAFTS LATER TODAY. THE MAIN TRIGGER IS SOME
SUBTLE ENERGY NOW IN EASTERN IDAHO MOVING NORTHEAST ASSOCIATED
WITH A JETLET IN THE SW FLOW ALOFT. THIS FEATURE WILL NOT BE AS
STRONG AS YESTERDAYS SHORT WAVE TROUGH...BUT ADEQUATE TO GET
THINGS GOING. MY FEELING IS THE POTENTIAL FOR REACHING SEVERE
LIMITS WITH STORMS TODAY HAS BEEN DEGRADED BY THE CLOUD COVER.
ANALYSIS INDICATES THE EASTERN ZONES NEAR THE BORDER ARE PRETTY
WELL CAPPED AND WILL LIKELY STAY THAT WAY THROUGH AT LEAST THE
AFTERNOON. THE CENTRAL ZONES...INCLUDING BILLINGS...WHERE THE
INSTABILITY AXIS EXISTS HAS NOT BEEN ABLE TO HEAT UP MUCH YET
EITHER. SOME OF THE SREF SEVERE WEATHER INDICES ARE THUS BACKING
OFF A BIT ON THE POTENTIAL FOR SEVERE STORMS IN OUR AREA. SO MY
CONFIDENCE HAS DECREASED IN A WIDESPREAD SEVERE WEATHER EVENT FOR
OUR FORECAST AREA TODAY. THE WESTERN ZONES HAVE THE BEST CHANCE OF
SEEING STRONG TO SEVERE STORMS DUE TO THEIR WARMER SURFACE TEMPS
AND PROXIMITY TO SHORT WAVE ENERGY. THAT SAID...SHOWERS AND
THUNDERSTORMS STILL LOOK LIKE A GOOD BET FOR THE WESTERN AND
CENTRAL ZONES THROUGH EVENING...JUST NOT AS STRONG AS YESTERDAY.
ALSO...WITH OUR PRECIP WATER VALUES NEAR AN INCH OR MORE HEAVY
RAIN IS STILL QUITE POSSIBLE. THE FLASH FLOOD WATCHES ACROSS OUR
AREA ARE THUS IN GOOD SHAPE...WITH THE PINE CREEK BURN SCAR AND
MUSSELSHELL COUNTY BURN SCARS GENERALLY THE MOST UNDER THE GUN
THIS EVENING.
THURSDAY...THE UPPER TROUGH OFF THE PACIFIC NW COAST MOVES INTO
THE NORTHERN ROCKIES AND WILL DRIVE A MID LEVEL FRONT ACROSS OUR
REGION BY EVENING. THE MODELS HOLD MOST OF THE CONVECTION OUT OF
OUR AREA UNTIL EVENING...THEN SWEEP A STRONG WIND SHIFT OVER
SOUTHERN MONTANA. INGREDIENTS ARE THERE FOR HAIL AND WIND THREATS
MAINLY EAST OF A ROUNDUP TO BROADUS LINE.
FRIDAY...STRONG WESTERLY FLOW OVER THE AREA WILL DRY OUT THE
ATMOSPHERE. THE TROUGH WILL BE PASSING OVER WITH COOL MID LEVELS
LIMITING OUR AFTERNOON HIGHS. HAVE LOWERED TEMPS FOR FRIDAY A BIT.
BT
.LONG TERM...VALID FOR SAT...SUN...MON...TUE...WED...
A QUIET WEATHER PATTERN IS EXPECTED FOR THE UPCOMING WEEKEND. A
COLD FRONT WILL MOVE THROUGH THE FORECAST AREA FRIDAY AS AN UPPER
LOW MOVES ACROSS SOUTHERN CANADA. THE FRONT WILL USHER IN DRIER
AIR FOR SATURDAY ALONG WITH BREEZY WESTERLY SURFACE WINDS. A
WEAKER FRONT DROPS DOWN FROM NORTHERN MONTANA LATE SATURDAY NIGHT
INTO SUNDAY MORNING BRINGING LIGHT NORTH TO NORTHEAST WINDS.
HOWEVER...NOT MUCH IF ANY MOISTURE LOOKS TO BE ASSOCIATED WITH
THIS FRONT AND GIVEN DRIER WEST TO NORTHWEST SURFACE FLOW...NOT
LOOKING FOR ANY SHOWER/THUNDERSTORM ACTIVITY AT THIS TIME. HIGH
PRESSURE RIDGING BEGINS TO BUILD SUNDAY INTO MONDAY. HOWEVER...A
FEW WEAK DISTURBANCES MAY UNDERCUT THIS RIDGE RESULTING IN A
SLIGHT SHOWER/THUNDERSTORM CHANCE MAINLY OVER AND NEAR THE
MOUNTAINS.
BY TUESDAY INTO WEDNESDAY...MODELS BRING ANOTHER UPPER LOW ONTO
THE PACIFIC NORTHWEST COAST BRINGING AN UNSETTLED SOUTHWEST FLOW
ALOFT TO THE FORECAST AREA. SEVERAL DISTURBANCES WITHIN THIS FLOW
WILL ALSO MOVE ACROSS OUR FORECAST AREA BRINGING RETURNED
THUNDERSTORM CHANCES. HOOLEY
&&
.AVIATION...
SHOWERS AND THUNDERSTORMS WILL INCREASE IN COVERAGE THIS
AFTERNOON MAINLY ALONG AND WEST OF A ROUNDUP-BILLINGS-SHERIDAN
LINE WITH THE ACTIVITY DEVELOPING EAST OF THIS LINE BY LATE THIS
AFTERNOON. THE THUNDERSTORMS WILL CONTAIN VERY HEAVY RAINFALL
ALONG WITH THE POSSIBILITY OF LARGE HAIL AND STRONG WIND GUSTS IN
EXCESS OF 50KTS. EXPECT MVFR TO LIFR CONDITIONS IN AND NEAR THE
THUNDERSTORM ACTIVITY. THE THUNDERSTORMS WILL BEGIN TO DIMINISH
LATE THIS EVENING. MOUNTAIN OBSCURATIONS WILL BE LIKELY THROUGH
THIS AFTERNOON AND INTO THE OVERNIGHT HOURS. HOOLEY
&&
.PRELIMINARY POINT TEMP/POPS...
THU FRI SAT SUN MON TUE WED
-----------------------------------------------------------
BIL 057/083 052/072 048/078 051/079 052/080 055/085 052/077
62/T 63/T 10/U 01/U 12/T 22/T 12/T
LVM 049/078 043/066 043/078 043/079 045/081 046/084 049/075
64/T 54/T 20/U 01/U 12/T 22/T 22/T
HDN 056/085 052/073 048/078 050/080 051/080 056/088 052/081
62/T 63/T 10/U 11/U 12/T 22/T 12/T
MLS 057/085 055/074 051/078 053/079 053/078 055/084 057/082
22/T 83/T 10/U 11/U 12/T 22/T 22/T
4BQ 054/089 054/073 049/078 050/080 051/079 055/087 055/087
22/T 52/T 10/U 11/U 12/T 22/T 11/U
BHK 053/079 056/072 049/076 050/075 050/075 054/080 058/079
32/T 52/W 10/U 11/U 12/T 22/T 11/U
SHR 052/086 050/072 044/078 047/078 049/079 053/086 050/085
42/T 52/T 10/U 11/U 12/T 22/T 12/T
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...SEVERE THUNDERSTORM WATCH 299 IN EFFECT UNTIL 10 PM MDT THIS
EVENING FOR ZONES 28-34-40>42-63>68.
FLASH FLOOD WATCH IN EFFECT UNTIL MIDNIGHT MDT TONIGHT FOR
ZONES 29-31-34-36>38-42-57-58-64-65-67.
WY...FLASH FLOOD WATCH IN EFFECT UNTIL MIDNIGHT MDT TONIGHT FOR
ZONE 99.
&&
$$
WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
1228 PM CDT WED JUN 12 2013
.AVIATION...
18Z TAFS FOR KOFK...KOMA AND KLNK.
VFR CIGS AND VSBYS EXPECTED BUT GUSTY NORTHWEST WINDS WILL OCCUR
DURING THE DAYLIGHT HOURS TODAY. NORTHWEST WINDS WILL LIKELY GUST
TO NEAR 30 KNOTS BEFORE SUNSET...THEN RAPIDLY DIMINISH. ANY
LINGERING CLOUDS WILL ALSO DISSIPATE AFTER DARK AS HIGH PRESSURE
BUILDS INTO THE REGION. THE MORNING HOURS SHOULD HAVE CLEAR SKIES
AND LIGHT WINDS.
NIETFELD
&&
.PREV DISCUSSION... /ISSUED 242 AM CDT WED JUN 12 2013/
DISCUSSION...
LOW PRESSURE WAS LOCATED OVER SOUTH CENTRAL NEBRASKA AT 07Z
WITH A COLD FRONT TRAILING INTO WESTERN KANSAS AND A WARM FRONT
EXTENDING ACROSS SOUTHEAST NEBRASKA AND SOUTHWEST IOWA. CONVECTION
WAS ONGOING OVER EASTERN NEBRASKA INTO WEST CENTRAL AND NORTHWEST
IOWA.
LATEST HRRR MODEL TRACKS THE SURFACE LOW EAST TOWARD SOUTHWEST
IOWA THIS MORNING WITH THE COLD FRONT MOVING THROUGH THE AREA BY
18Z. CURRENT CONVECTION IS EXPECTED TO PUSH EAST OF THE AREA BY
THIS SAME TIME IN ADVANCE OF THE LOW AND NORTH OF THE WARM FRONT.
HIGH PRESSURE THEN BUILDS INTO THE PLAINS REGION THIS AFTERNOON
AND TONIGHT. AS THE HIGH MOVES EAST INTO THE MISSISSIPPI VALLEY
ON THURSDAY SOUTHERLY FLOW RETURNS TO THE PLAINS ALONG WITH A WARM
ADVECTION PATTERN AND THE CHANCE OF THUNDERSTORMS FOR THURSDAY
NIGHT INTO FRIDAY MORNING. AS ANOTHER STRONG UPPER WAVE MOVES INTO
THE NORTHERN PLAINS ON FRIDAY A COLD FRONT MOVES INTO THE AREA
AGAIN FRIDAY NIGHT WITH ANOTHER CHANCE OF STORMS FOR THE AREA.
EXTENDED MODELS STILL SHOW SOME POTENTIAL FOR ADDITIONAL STORMS
SATURDAY INTO SUNDAY. WITH THE UPPER PATTERN REMAINING STRONG AND
ACTIVE THROUGH MID WEEK PERIODS OF STORMS STILL INDICATED FOR THE
AREA DURING THIS TIME.
FOBERT
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS ALBUQUERQUE NM
314 PM MDT WED JUN 12 2013
.DISCUSSION...
NOT TOO MUCH CHANGE TO THE GOING FORECAST. TEMPERATURES CONTINUE TO
CREEP UP THIS AFTERNOON AREAWIDE. TEMPS ARE NOT AS QUICK TO RISE
TODAY THANKS TO A LITTLE CLOUD COVER ACROSS THE WEST AND NORTH AND
EAST TO SOUTHEASTERLY SURFACE WINDS ACROSS THE PLAINS. SATELLITE
IMAGERY SHOWING A NICE BUBBLING OF CU EXTENDING FROM THE SANGRE DE
CRISTOS SOUTHWARD TO THE SACRAMENTO MOUNTAINS. THIS WILL BE THE
FAVORED AREA FOR ANY LIGHT SHOWERS...VIRGA AND/OR DRY THUNDERSTORMS
THIS EVENING...THOUGH THE HRRR AND THE NAM WERE SHOWING A BIT OF QPF
ACROSS THE FAR NORTHEAST WHERE SOUTHEASTERLY FLOW IS CURRENTLY
BRINGING HIGHER DEWPOINTS UP ONTO THE RATON RIDGE. ANY ACTIVITY THAT
DEVELOPS SHOULD DIMINISH BY MIDNIGHT...IF NOT SHORTLY AFTER SUNSET.
ANOTHER WARM NIGHT IS IN STORE ACROSS THE EASTERN PLAINS. RECORD
HEAT FOR THURSDAY IS NOT EXPECTED TO BE AS WIDESPREAD. THE
COMBINATION OF AN UPPER LEVEL TROUGH ACROSS THE NORTHWEST CONUS AND
AND UPPER LEVEL DISTURBANCE MOVING NORTHWARD ACROSS MEXICO WILL
RESULT IN THE UPPER LEVEL HIGH SHIFTING EAST. FORECAST SOUNDINGS
CONTINUE TO SHOW STRONG INVERTED-V SIGNATURES UP TO ROUGHLY 500 MB
SUGGESTING CONTINUED POTENTIAL OF MOSTLY DRY THUNDERSTORMS ACROSS
THE WEST AND NORTHWEST PORTIONS OF THE CWA. FURTHER EAST...A POCKET
OF DRY AIR AHEAD OF THE APPROACHING DISTURBANCE FROM THE SOUTH WILL
LIMIT SHOWER AND T-STORM POTENTIAL...AT LEAST THROUGH MUCH OF THE
DAY. IF THE GFS VERIFIES...SOME CHANCE WILL EXIST IN THE
EVENING...BUT AT THIS POINT...NOT AS CONFIDENT ABOUT THAT.
THOUGH THE UPPER LOW WILL TRACK OVER SE NM AND WEST TEXAS...SELY
FLOW WILL BRING BETTER MOISTURE BACK TO THE CENTRAL MOUNTAIN CHAIN
AND PERHAPS INTO THE RIO GRANDE VALLEY THURSDAY NIGHT INTO FRIDAY
MORNING. BETWEEN THE ADDED MOISTURE..PERHAPS A SLIGHT COOLING AT
MID LEVELS...AND SOME WEAK CONVERGENCE AT MID LEVELS BETWEEN THE
SELY FLOW ACROSS THE EAST AS A RESULT OF THE LOW...AND WSW FLOW AT
MID LEVELS ACROSS THE WEST FOLLOWING THE PASSAGE OF THE NW
TROUGH...CENTRAL PORTIONS OF THE STATE WILL BE THE FAVORED AREA
FOR PRECIPITATION ON FRIDAY. THOUGH AMOUNTS WILL LIKELY BE
MODEST...WITH FEW EXCEPTIONS...THERE IS A BETTER CHANCE OF
MEASURABLE RAINFALL THAN WE HAVE SEEN IN A WHILE. HOWEVER...A
CHANCE FOR DRY THUNDERSTORMS REMAINS ACROSS WESTERN AREAS...ON THE
FRINGES OF THE BETTER MOISTURE. THE OTHER GOOD NEWS IS...WITH THE
ADDED CLOUD COVER AND PRECIPITATION... TEMPERATURES WILL TREND
DOWN TO NEAR NORMAL VALUES.
MOISTURE WILL RECYCLE IN THE FORM OF SHOWERS AND THUNDERSTORMS ON
SATURDAY AS THE UPPER LEVEL LOW SLOWLY DEPARTS WEST TEXAS. THEN MORE
WEST OR SOUTHWESTERLY FLOW LOOKS TO TAKE SHAPE ON SUNDAY...AND
MOISTURE ONCE AGAIN PLUMMETS. TEMPS WILL ALSO JUMP BACK UP A FEW
DEGREES. MODELS CONTINUE TO WAVER ON A BACK DOOR COLD FRONT ON
MONDAY AND THE ASSOCIATED MOISTURE IT MAY OR MAY NOT BRING TO THE
EAST. AFTER WHICH...HOWEVER...IT APPEARS A DRIER SOUTHWESTERLY FLOW
WILL BE THE RULE THROUGH MID WEEK AS THE UPPER HIGH RE-ESTABLISHES
ITSELF OVER TEXAS.
34
&&
.FIRE WEATHER...
ELONGATED UPPER LEVEL RIDGE OVER THE AREA WILL GRADUALLY WEAKEN AND
SHIFT EASTWARD THROUGH FRIDAY. AT THE SAME TIME...A TROPICAL
DISTURBANCE CURRENTLY OVER CENTRAL MEXICO WILL SLOWLY DRIFT
NORTHWARD INITIALLY BEFORE FOLLOWING A MORE NELY TRAJECTORY BY
WEEK/S END. THIS LARGE-SCALE PATTERN SHIFT WILL BRING A TEMPORARY
END TO OUR RECORD-SETTING HEAT AS WELL AS A RATHER SIGNIFICANT
INCREASE IN THUNDERSTORM ACTIVITY EAST OF THE DIVIDE BY FRIDAY AND
FRIDAY EVENING. UNFORTUNATELY...THE THREAT OF DRY LIGHTNING WILL BE
A CONCERN FOR MANY AREAS TOMORROW BUT A TREND TOWARD WETTER STORMS
IS EXPECTED BY FRIDAY ESPECIALLY FOR AREAS NEAR THE CENTRAL MOUNTAIN
CHAIN.
THERE WILL STILL BE A PRONOUNCED WESTWARD EXTENSION OF THE RIDGE
OVER THE AREA ON THURSDAY BUT THE SUBTLE EASTWARD SHIFT OF THE
PRIMARY HIGH CENTER WILL ALLOW FOR SLIGHT COOLING ALOFT THAT COMBINED
WITH A GRADUAL MOISTENING OF THE LOWER ATMOSPHERE FROM THE
MID-LEVELS DOWN WILL RESULT IN A THREAT FOR ISOLATED DRY
THUNDERSTORMS OVER THE HIGHER TERRAIN OF THE WEST ON THURSDAY WITH A
TREND TOWARD ISOLATED MIXED WET/DRY STORMS ALONG AND IMMEDIATELY
EAST OF THE CENTRAL MOUNTAIN CHAIN. THE OTHER CONCERN ON THURSDAY
WILL BE INCREASING SOUTH-SOUTHWEST WINDS ACROSS THE NORTHEAST
QUARTER. DEW POINTS WILL BE ON THE INCREASE HERE BUT WITH A
SLIGHTLY DOWNSLOPE COMPONENT HAVE TRENDED DRIER THAN THE GFS BUT
SLIGHTLY ABOVE THE NAM THAT IS BY FAR THE DRIEST. THE END RESULT
COULD BE SEVERAL HOURS OF CRITICAL FIRE WEATHER CONDITIONS ACROSS
THE NORTHEAST PLAINS. DO HAVE SOME CONCERN FOR A COUPLE HOURS OF RED
FLAG CONDITIONS ACROSS EASTERN PORTIONS OF ZONE 103-- ALONG AND EAST
OF THE INTERSTATE 25 CORRIDOR. LEFT THIS AREA OUT OF THE RED FLAG
WARNING GIVEN LIMITED IMPACT.
HUMIDITY RECOVERY TONIGHT WILL NOT BE NEAR AS BRUTAL AS THE PAST TWO
NIGHTS BUT STILL FAIR TO POOR FOR WESTERN AREAS AND THE HIGHEST
TERRAIN OF THE NORTH. MIN RH VALUES ON THURSDAY WILL BE TRENDING
UPWARD WITH SINGLE DIGIT READINGS CONFINED TO LOWER ELEVATIONS WEST
OF THE DIVIDE.
THE ABOVE MENTIONED TROPICAL LOW SHOULD BE PASSING OVER OR VERY
NEAR SOUTHEAST NEW MEXICO FRIDAY NIGHT....THOUGH MODELS DIFFER
WHEN IT MAKES ITS TURN TO THE NORTHEAST. TRENDED DEW POINTS UPWARD
CENTRAL AND ESPECIALLY EASTERN AREAS AND COULD SEE DECENT WETTING
RAIN POTENTIAL AT NIGHT ACROSS PARTS OF THE EC/SE PLAINS NEARER
THE LOW/S CORE. OTHERWISE...FRIDAY EVENING LOOKS TO BE AMONG THE
MORE ACTIVE PERIODS OF THUNDERSTORM ACTIVITY THIS FORECAST CYCLE.
THE UPPER HIGH WILL RESTRENGTHEN OVER THE AREA AS THE WEEKEND
PROGRESSES WITH DRIER AIR BECOMING PREDOMINATE. THIS SHOULD ALLOW
WARMER THAN AVERAGE DAYTIME TEMPERATURES TO RETURN ALONG WITH LOWER
HUMIDITIES ESPECIALLY CENTRAL AND WEST.
KJ
&&
.AVIATION...
18Z TAF CYCLE
VFR CONDITIONS WILL PREDOMINATE THROUGH AT LEAST 12Z THU. MODERATE
SFC WINDS WILL OCCASIONALLY GUST TO 20-25 KTS BUT SPEEDS WILL BE
LESS THAN YESTERDAY. HIGHEST CONFIDENCE IN SURFACE SMOKE IMPACTS
TO KSAF LATER TONIGHT WITH SMOKE LAYERS ALOFT JUST ABOUT ANYWHERE
WITH TRANSPORT WINDS GENERALLY FROM SW TO NE. ISOLATED HIGH BASED
-SHRA AND -TSRA ACROSS MAINLY THE CENTRAL MT CHAIN AND THE ADJACENT
HIGHLANDS IMMEDIATELY TO THE EAST BETWEEN ROUGHLY 20Z AND 04Z.
LOCALIZED GUSTY WINDS THE MAIN CONCERN WITH THIS ACTIVITY. KJ
&&
.PRELIMINARY POINT TEMPS/POPS...
FARMINGTON...................... 57 97 59 93 / 0 0 5 5
DULCE........................... 42 89 41 87 / 0 10 10 10
CUBA............................ 53 90 50 88 / 5 20 10 10
GALLUP.......................... 49 92 50 89 / 0 5 10 5
EL MORRO........................ 47 86 44 84 / 0 20 10 10
GRANTS.......................... 48 92 51 89 / 0 20 10 10
QUEMADO......................... 56 89 55 86 / 5 10 10 10
GLENWOOD........................ 53 96 50 93 / 0 0 10 10
CHAMA........................... 44 84 46 82 / 5 20 20 10
LOS ALAMOS...................... 66 88 65 83 / 5 10 10 20
PECOS........................... 64 85 60 81 / 10 10 20 20
CERRO/QUESTA.................... 55 83 54 80 / 5 10 10 20
RED RIVER....................... 50 77 46 74 / 10 20 20 30
ANGEL FIRE...................... 37 80 38 77 / 10 10 10 30
TAOS............................ 49 88 51 87 / 5 10 10 20
MORA............................ 58 83 55 78 / 10 10 10 20
ESPANOLA........................ 60 92 59 89 / 5 5 10 10
SANTA FE........................ 63 90 59 84 / 5 5 10 20
SANTA FE AIRPORT................ 61 94 60 89 / 5 5 10 10
ALBUQUERQUE FOOTHILLS........... 68 95 68 90 / 5 5 10 10
ALBUQUERQUE HEIGHTS............. 69 97 69 92 / 5 5 10 10
ALBUQUERQUE VALLEY.............. 66 98 67 93 / 5 5 10 20
ALBUQUERQUE WEST MESA........... 65 98 66 93 / 5 5 10 10
LOS LUNAS....................... 64 98 65 94 / 0 5 10 20
RIO RANCHO...................... 64 98 66 94 / 5 5 10 10
SOCORRO......................... 66 101 65 96 / 0 5 10 20
SANDIA PARK/CEDAR CREST......... 60 93 59 88 / 5 10 20 20
TIJERAS......................... 64 94 62 90 / 5 5 10 20
MORIARTY/ESTANCIA............... 57 90 57 85 / 10 5 10 30
CLINES CORNERS.................. 60 90 58 85 / 10 5 10 30
GRAN QUIVIRA.................... 64 91 61 86 / 10 10 20 30
CARRIZOZO....................... 62 93 60 88 / 5 5 10 20
RUIDOSO......................... 59 83 56 77 / 10 10 20 40
CAPULIN......................... 57 91 58 83 / 10 5 5 20
RATON........................... 57 91 56 88 / 10 5 10 20
SPRINGER........................ 56 91 56 87 / 10 5 10 20
LAS VEGAS....................... 57 88 56 83 / 10 5 10 20
CLAYTON......................... 68 97 67 92 / 5 0 5 5
ROY............................. 63 91 62 86 / 5 5 10 10
CONCHAS......................... 69 94 67 90 / 0 0 5 5
SANTA ROSA...................... 66 93 66 88 / 0 0 10 10
TUCUMCARI....................... 70 100 70 95 / 0 0 5 5
CLOVIS.......................... 65 93 64 88 / 0 0 5 10
PORTALES........................ 66 94 66 88 / 0 0 5 20
FORT SUMNER..................... 68 94 67 89 / 0 0 5 10
ROSWELL......................... 68 95 68 90 / 0 0 10 20
PICACHO......................... 62 89 61 84 / 5 5 10 20
ELK............................. 60 84 58 79 / 5 5 20 30
&&
.ABQ WATCHES/WARNINGS/ADVISORIES...
RED FLAG WARNING FROM 2 PM TO 8 PM MDT THURSDAY FOR THE FOLLOWING
ZONES...NMZ104.
&&
$$
34
AREA FORECAST DISCUSSION
NWS BUFFALO NY
611 PM EDT WED JUN 12 2013
.SYNOPSIS...
LOW PRESSURE WILL TRACK ACROSS PENNSYLVANIA LATE TONIGHT AND
THURSDAY. THIS WILL BRING A ROUND OF SHOWERS AND THUNDERSTORMS TO
THE SOUTHERN TIER LATE TONIGHT AND THURSDAY...WITH MORE SCATTERED SHOWERS
ELSEWHERE ON THURSDAY. AFTER THIS...HIGH PRESSURE WILL BUILD ACROSS
THE REGION LATE FRIDAY...BRINGING A RETURN TO FAIR WEATHER SATURDAY.
&&
.NEAR TERM /THROUGH THURSDAY/...
OUR MAIN FOCUS WILL BE THE EXPECTED DEVELOPMENT OF A SIGNIFICANT
CONVECTIVE COMPLEX ACROSS THE MID-WESTERN STATES THIS EVENING. A
CONSENSUS OF THE 12 AND 18Z MODEL GUIDANCE HAS TRENDED SOUTH WITH
THE TRACK OF THIS FEATURE...WHICH IS CONSISTENT WITH OUR FORECAST
EXPECTATION THAT THE MCS IS LIKELY VEER TO THE RIGHT (SOUTHWARD)
TOWARD THE MORE UNSTABLE AIR. BECAUSE OF THIS...HAVE BEEN ABLE TO
TIGHTEN THE POP GRADIENT...RESULTING IN A DRIER FORECAST
BUFFALO-ROCHESTER NORTHWARD...WHILE CONFIDENCE REMAINS HIGH NEAR THE
NY/PA LINE. OUR REGION WILL BE ON THE NORTHERN FRINGE OF THE
COMPLEX...A SECTOR WHICH IS LESS LIKELY TO HAVE ANY SEVERE WEATHER
ASSOCIATED WITH IT. THE RGEM CONTINUES TO BE A NORTHWARD OUTLIER
AMONG MODEL GUIDANCE...SUGGESTING THERE IS A SMALL BUT DIMINISHING
CHANCE OF A MORE NORTHWARD TRACK WHICH WOULD BRING HEAVIER RAINS
INTO WESTERN NEW YORK.
GIVEN GENERAL SUPPORT FROM THE NAM/GFS/SREF...FEEL THE HRRR IS ON
THE RIGHT TRACK AND WILL BE ABLE TO MOST EFFECTIVELY CAPTURE THE
TRACK OF THE MCS TONIGHT...AND SHOULD HAVE GOOD SKILL ADVECTING THE
COMPLEX ONCE IT FULLY DEVELOPS. THERE MAY BE AN INITIAL ROUND OF
THUNDERSTORMS AHEAD OF THIS LATE EVENING...WHICH WOULD TRACK ACROSS
WESTERN PENNSYLVANIA AND FAR SOUTHERN NEW YORK. THE MAIN COMPLEX IS
FORECAST TO REACH THE OH/PA LINE AROUND 400 AM. THE CORE OF THIS
SHOULD PASS TO OUR SOUTH IT WILL LIKELY CLIP SOUTHERN PORTIONS OF
THE CWA DURING THE EARLY MORNING HOURS THROUGH MID-MORNING.
ASSOCIATED RAIN WILL LIKELY BE BUFFALO-ROCHESTER SOUTHWARD. ALONG
THE NY/PA BORDER...EXPECT PERIOD OF MODERATE TO HEAVY RAIN...WITH
SOME EMBEDDED THUNDERSTORMS POSSIBLE.
ON THURSDAY...EXPECT THE COMPLEX TO MAINTAIN STRENGTH AS IT
CONTINUES TO MOVE ACROSS PENNSYLVANIA. A SECONDARY UPPER LEVEL
SHORTWAVE WILL CATCH UP TO THE FEATURE DURING THE DAY...AND THIS
WILL LIKELY ALLOW ASSOCIATED PRECIPITATION TO SPREAD FURTHER TO THE
NORTH. BY THIS TIME...THE COMPLEX AND ASSOCIATED LOW WILL LIKELY BE
ACROSS EASTERN PENNSYLVANIA...WITH ONLY A MODEST NORTHWARD SPREAD OF
SHOWERS IN EASTERN PORTIONS OF OUR CWA. THIS SHORTWAVE MAY GENERATE
SOME LIGHT SHOWERS ON ITS OWN DURING THE LATE AFTERNOON.
FLOOD POTENTIAL IS COMPLETELY DEPENDENT ON THE TRACK OF THE
CONVECTIVE COMPLEX. GIVEN THE EXPECTED TRACK...THE HEAVIEST RAIN
WOULD REMAIN SOUTH OF OUR FORECAST AREA. RAINFALL AMOUNTS OF AROUND
AN INCH ARE EXPECTED NEAR THE NY/PA BORDER...WITH THESE LIKELY TO
DROP OFF RAPIDLY NORTHWARD. THERE STILL IS A SLIGHT CHANCE THE HEAVY
RAINS WILL MAKE IT INTO NEW YORK IF SOME OF THE OUTLIER MODEL
GUIDANCE VERIFIES. OBSERVATIONAL TRENDS SHOULD HELP FINE-TUNE THE
FORECAST DURING THE EVENING HOURS. ONE OTHER THING TO NOTE IS THAT
SOME OF OUR BASINS DO EXTEND INTO FAR NORTHERN PENNSYLVANIA. MMEFS
ENSEMBLES SHOW LOW CHANCES FOR FLOODING ON THE ALLEGHENY AT OLEAN
AND THE GENESEE AT WELLSVILLE...MAINLY DUE TO UPSTREAM RAINS. AT
THIS TIME...CONFIDENCE IS WELL BELOW WATCH THRESHOLD...BUT WILL
CONTINUE TO MENTION THIS POTENTIAL IN THE HWO.
TEMPERATURES WILL DROP ONLY MODESTLY OVERNIGHT IN MOST
LOCATIONS...WITH LOWS MAINLY IN THE UPPER 50S TO LOWER 60S. IT WILL
BE A BIT COOLER EAST OF LAKE ONTARIO WHERE CLOUDS WILL NOT MOVE IN
UNTIL LATER. ON THURSDAY...HIGHS SHOULD RANGE FROM THE UPPER 60S TO
AROUND 70.
&&
.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY NIGHT/...
BY THURSDAY EVENING THE STRONG MID LEVEL CIRCULATION AND ASSOCIATED
SURFACE LOW WILL BE REACHING THE DELMARVA PENINSULA...CARRYING ANY
SHOWERS WELL SOUTH AND EAST OF THE AREA. OUR ATTENTION THEN TURNS TO
ANOTHER MUCH WEAKER NORTHERN STREAM SHORTWAVE...WHICH WILL BE
DIGGING ACROSS THE LOWER LAKES IN THE EVENING AND WILL EVENTUALLY
PHASE WITH THE FIRST SYSTEM OVERNIGHT. THE DEEPER MOISTURE
ASSOCIATED WITH THIS SECOND FEATURE WILL BE BEHIND THE MID LEVEL
SHORTWAVE AND CLOSER TO A WEAK LOW LEVEL TROUGH. THIS MAY TOUCH OFF
A FEW MORE SHOWERS OVERNIGHT INTO FRIDAY MORNING AS IT CROSSES THE
REGION...BUT THEY SHOULD BE WIDELY SCATTERED AND LIGHT IN NATURE.
BY FRIDAY AFTERNOON DEEPER MOISTURE AND LIFT WITH THIS SECOND WAVE
WILL MOVE SOUTHEAST OF THE AREA...WITH A MUCH DRIER AIRMASS
ADVECTING INTO THE LOWER LAKES DURING THE AFTERNOON. ANY LEFTOVER
SCATTERED SHOWERS THROUGH MIDDAY WILL END FROM NORTHWEST TO
SOUTHEAST DURING THE AFTERNOON WITH CLEARING SKIES LATE IN THE DAY.
FRIDAY NIGHT INTO SATURDAY HIGH PRESSURE WILL BUILD INTO THE GREAT
LAKES AND OHIO VALLEY. THIS WILL BRING A RETURN TO DRY AND CLEAR
WEATHER...AND ALSO DELIVER A COOLER/DRIER AIRMASS INTO THE REGION.
LOWS WILL BE ON THE COOL SIDE FRIDAY NIGHT WITH LOWER 50S ON THE
LAKE PLAINS AND 40S IN THE INTERIOR SOUTHERN TIER AND EAST OF LAKE
ONTARIO. AFTER A COOL START...SATURDAY WILL WARM NICELY UNDER FULL
SUNSHINE WITH 850MB TEMPS AROUND +9C. THIS SHOULD SUPPORT HIGHS IN
THE LOWER TO MID 70S AT LOWER ELEVATIONS. THE WEAK SYNOPTIC SCALE
PRESSURE GRADIENT AND STRONG DIFFERENTIAL HEATING WILL SUPPORT LAKE
BREEZE DEVELOPMENT WITH COOLER TEMPS ALONG THE LAKESHORES.
SATURDAY NIGHT HIGH PRESSURE WILL BEGIN TO DRIFT TO THE EASTERN
SEABOARD...WITH SOUTHWEST RETURN FLOW BEGINNING. THIS WILL HELP KEEP
LOWS A LITTLE MORE MILD THAN FRIDAY NIGHT ESPECIALLY ACROSS WESTERN
NY. INCREASING WARM ADVECTION AND ISENTROPIC UPGLIDE WILL BRING SOME
INCREASE IN CLOUDS FROM WEST TO EAST OVERNIGHT.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
BY SUNDAY THE RIDGE ACROSS THE CENTRAL CONUS WILL BEGIN TO BREAK
DOWN AS FLOW BECOMES ZONAL AGAIN OVER THE NORTHERN TIER OF THE
NATION. THIS WILL ALLOW A SERIES OF WEAK AND FAST MOVING SHORTWAVES
TO MOVE THROUGH THE GREAT LAKES REGION. THE 12Z GFS AND ECMWF HAVE
COME INTO A LITTLE BETTER AGREEMENT TODAY WITH RESPECT TO SUNDAY...
AS BOTH MOVE THE FIRST SHORTWAVE INTO THE LOWER LAKES DURING THE
DAY. THIS MAY TOUCH OF A FEW SCATTERED SHOWERS AND THUNDERSTORMS
DURING THE AFTERNOON...ALTHOUGH IT LOOKS LIKE COVERAGE WILL REMAIN
SPARSE. THE NEXT IN A SERIES OF SHORTWAVES WILL CROSS THE AREA
MONDAY OR MONDAY NIGHT WITH A CHANCE OF A FEW MORE SHOWERS AND
STORMS...ALTHOUGH TIMING OF INDIVIDUAL WAVES IS UNCERTAIN AT THIS
TIME RANGE.
BY TUESDAY AND WEDNESDAY MODEL UNCERTAINTY BEGINS TO INCREASE AS THE
ECMWF HANGS ONTO MORE OF A TROUGH AND DEEPER MOISTURE ACROSS THE
GREAT LAKES. THIS WOULD ALLOW AT LEAST A LOW CHANCE OF SHOWERS AND A
FEW THUNDERSTORMS TO LINGER TUESDAY AND WEDNESDAY. THE GFS ON THE
OTHER HAND PUSHES THE TROUGH A LITTLE FARTHER EAST...WITH HIGH
PRESSURE BUILDING INTO THE GREAT LAKES LATER TUESDAY AFTERNOON AND
WEDNESDAY. FOR NOW WILL STICK CLOSE TO PREVIOUS FORECAST CONTINUITY
WITH A LOW CHANCE ON TUESDAY THEN DRY ON WEDNESDAY UNTIL BETTER
MODEL AGREEMENT IS REACHED.
TEMPERATURES WILL WARM TO A LITTLE ABOVE AVERAGE BY SUNDAY AND
MONDAY AS A WARMER AIRMASS MOVES INTO THE AREA FROM THE MIDWEST. IF
THE MORE PROGRESSIVE GFS VERIFIES...TEMPERATURES WOULD COOL BACK TO
AVERAGE AS HIGH PRESSURE BUILDS INTO THE GREAT LAKES.
&&
.AVIATION /22Z WEDNESDAY THROUGH MONDAY/...
VFR CONDITIONS WILL CONTINUE AREA-WIDE THROUGH THIS EVENING AS WEAK
HIGH PRESSURE BUILDS ACROSS NEW YORK STATE.
AFTER THIS...THE FORECAST WILL DEPEND ON THE EVOLUTION OF A STRONG
CONVECTIVE COMPLEX WHICH IS FORECAST TO DEVELOP ACROSS THE MID-
WEST AND TRACK ESE ACROSS PENNSYLVANIA. AS THE COMPLEX STRENGTHENS
OVERNIGHT...IT WILL LIKELY CURVE TO THE RIGHT PUSHING IT SOUTHWARD
WHERE THE MORE UNSTABLE AIR LIES. GIVEN THIS LIKELIHOOD...EXPECT
ONLY A MINIMAL IMPACT ON ALL OF OUR TAF SITES WITH THE EXCEPTION OF
JHW...WHICH WILL LIKELY CATCH THE NORTHERN FRINGE OF THE ASSOCIATED
PRECIPITATION SHIELD. THIS SAID...THERE IS A SLIGHT CHANCE THIS
COMPLEX WILL TRACK NORTH OF THIS FORECAST...AND IF IT DOES IT WOULD
HAVE A SIGNIFICANT IMPACT ON THE BUF/IAG/ROC TERMINALS.
ON THURSDAY...THE CONVECTIVE COMPLEX AND ASSOCIATED LOW PRESSURE
WILL EXIT EAST...WITH A DEVELOPING NE FLOW. THIS WILL LIKELY LOWER
CIGS...BUT PROBABLY STILL JUST ABOVE 3000 FT IN THE VFR CATEGORY.
OUTLOOK...
THURSDAY NIGHT AND FRIDAY...MVFR/VFR WITH A CHANCE OF SHOWERS.
SATURDAY AND SUNDAY...MAINLY VFR.
&&
.MARINE...
LOW PRESSURE WILL PASS JUST TO THE SOUTH OF THE LOWER LAKES TONIGHT
AND THURSDAY...WITH WINDS INITIALLY INCREASING OUT OF THE
EAST...THEN BACKING TO NORTH DURING THURSDAY. AT THIS POINT...IT
STILL APPEARS THAT WINDS AND WAVES MAY INCREASE JUST ENOUGH TO
EVENTUALLY WARRANT SMALL CRAFT ADVISORIES FOR WESTERN LAKE ONTARIO
AND LAKE ERIE.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...APFFEL
NEAR TERM...APFFEL/RSH
SHORT TERM...HITCHCOCK
LONG TERM...AR/HITCHCOCK
AVIATION...APFFEL/RSH
MARINE...APFFEL/HITCHCOCK
AREA FORECAST DISCUSSION
NWS BUFFALO NY
348 PM EDT WED JUN 12 2013
.SYNOPSIS...
LOW PRESSURE WILL TRACK ACROSS PENNSYLVANIA LATE TONIGHT AND
THURSDAY. THIS WILL BRING A ROUND OF SHOWERS AND THUNDERSTORMS TO
THE SOUTHERN TIER LATE TONIGHT AND THURSDAY...WITH MORE SCATTERED SHOWERS
ELSEWHERE ON THURSDAY. AFTER THIS...HIGH PRESSURE WILL BUILD ACROSS
THE REGION LATE FRIDAY...BRINGING A RETURN TO FAIR WEATHER SATURDAY.
&&
.NEAR TERM /THROUGH THURSDAY/...
OUR MAIN FOCUS WILL BE THE EXPECTED DEVELOPMENT OF A SIGNIFICANT
CONVECTIVE COMPLEX ACROSS THE MID-WESTERN STATES LATE THIS
AFTERNOON. A CONSENSUS OF THE 12Z MODEL GUIDANCE HAS TRENDED
SOUTH WITH THE TRACK OF THIS...WHICH IS CONSISTENT WITH OUR FORECAST
EXPECTATION THAT THE MCS IS LIKELY VEER TO THE RIGHT (SOUTHWARD)
TOWARD THE MORE UNSTABLE AIR. BECAUSE OF THIS...HAVE BEEN ABLE TO
TIGHTEN THE POP GRADIENT...RESULTING IN A DRIER FORECAST
BUFFALO-ROCHESTER NORTHWARD...WHILE CONFIDENCE REMAINS HIGH NEAR THE
NY/PA LINE. OUR REGION WILL BE ON THE NORTHERN FRINGE OF THE
COMPLEX...A SECTOR WHICH IS LESS LIKELY TO HAVE ANY SEVERE WEATHER
ASSOCIATED WITH IT. THE RGEM CONTINUES TO BE A NORTHWARD OUTLIER
AMONG MODEL GUIDANCE...SUGGESTING THERE IS A SMALL BUT DIMINISHING
CHANCE OF A MORE NORTHWARD TRACK WHICH WOULD BRING HEAVIER RAINS
INTO WESTERN NEW YORK.
FOR THE REMAINDER OF THIS AFTERNOON...IT SHOULD CONTINUE TO BE
QUITE PLEASANT...WITH PARTLY TO MOSTLY SUNNY SKIES ACROSS WESTERN
NEW YORK AND TEMPERATURES MAINLY IN THE 70S. RADAR SHOWS A FEW LIGHT
SHOWERS STREAMING ACROSS NE OHIO AND EASTERN MICHIGAN...WITH THIS
ARE LIKELY TO LIFT TO AROUND CHAUTAUQUA COUNTY BEFORE FALLING APART
AROUND SUNSET.
GIVEN GENERAL SUPPORT FROM THE NAM/GFS/SREF...FEEL THE HRRR IS ON
THE RIGHT TRACK AND WILL BE ABLE TO MOST EFFECTIVELY CAPTURE THE
TRACK OF THE MCS...AND SHOULD HAVE GOOD SKILL ADVECTING THE
COMPLEX ONCE IT FULLY DEVELOPS. THERE MAY BE AN INITIAL ROUND OF
THUNDERSTORMS AHEAD OF THIS LATE EVENING...WHICH WOULD TRACK ACROSS
WESTERN PENNSYLVANIA AND FAR SOUTHERN NEW YORK LATE THIS EVENING.
THE MAIN COMPLEX IS FORECAST TO REACH THE OH/PA LINE AROUND 400 AM.
THE CORE OF THIS SHOULD PASS TO OUR SOUTH IT WILL LIKELY CLIP
SOUTHERN PORTIONS OF THE CWA DURING THE EARLY MORNING HOURS THROUGH
MID-MORNING. ASSOCIATED RAIN WILL LIKELY BE BUFFALO-ROCHESTER
SOUTHWARD. ALONG THE NY/PA BORDER...EXPECT PERIOD OF MODERATE TO
HEAVY RAIN...WITH SOME EMBEDDED THUNDERSTORMS POSSIBLE.
ON THURSDAY...EXPECT THE COMPLEX TO MAINTAIN STRENGTH AS IT
CONTINUES TO MOVE ACROSS PENNSYLVANIA. A SECONDARY UPPER LEVEL
SHORTWAVE WILL CATCH UP TO THE FEATURE DURING THE DAY...AND THIS
WILL LIKELY ALLOW ASSOCIATED PRECIPITATION TO SPREAD FURTHER TO THE
NORTH. BY THIS TIME...THE COMPLEX AND ASSOCIATED LOW WILL LIKELY BE
ACROSS EASTERN PENNSYLVANIA...WITH ONLY A MODEST NORTHWARD SPREAD OF
SHOWERS IN EASTERN PORTIONS OF OUR CWA. THIS SHORTWAVE MAY GENERATE
SOME LIGHT SHOWERS ON ITS OWN DURING THE LATE AFTERNOON.
FLOOD POTENTIAL IS COMPLETELY DEPENDENT ON THE TRACK OF THE
CONVECTIVE COMPLEX. GIVEN THE EXPECTED TRACK...THE HEAVIEST RAIN
WOULD REMAIN SOUTH OF OUR FORECAST AREA. RAINFALL AMOUNTS OF AROUND
AN INCH ARE EXPECTED NEAR THE NY/PA BORDER...WITH THESE LIKELY TO
DROP OFF RAPIDLY NORTHWARD. THERE STILL IS A SLIGHT CHANCE THE HEAVY
RAINS WILL MAKE IT INTO NEW YORK IF SOME OF THE OUTLIER MODEL
GUIDANCE VERIFIES. OBSERVATIONAL TRENDS SHOULD HELP FINE-TUNE THE
FORECAST DURING THE EVENING HOURS. ONE OTHER THING TO NOTE IS THAT
SOME OF OUR BASINS DO EXTEND INTO FAR NORTHERN PENNSYLVANIA. MMEFS
ENSEMBLES SHOW LOW CHANCES FOR FLOODING ON THE ALLEGHENY AT OLEAN
AND THE GENESEE AT WELLSVILLE...MAINLY DUE TO UPSTREAM RAINS. AT
THIS TIME...CONFIDENCE IS WELL BELOW WATCH THRESHOLD...BUT WILL
CONTINUE TO MENTION THIS POTENTIAL IN THE HWO.
TEMPERATURES WILL DROP ONLY MODESTLY OVERNIGHT IN MOST
LOCATIONS...WITH LOWS MAINLY IN THE UPPER 50S TO LOWER 60S. IT WILL
BE A BIT COOLER EAST OF LAKE ONTARIO WHERE CLOUDS WILL NOT MOVE IN
UNTIL LATER. ON THURSDAY...HIGHS SHOULD RANGE FROM THE UPPER 60S TO
AROUND 70.
&&
.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY NIGHT/...
BY THURSDAY EVENING THE STRONG MID LEVEL CIRCULATION AND ASSOCIATED
SURFACE LOW WILL BE REACHING THE DELMARVA PENINSULA...CARRYING ANY
SHOWERS WELL SOUTH AND EAST OF THE AREA. OUR ATTENTION THEN TURNS TO
ANOTHER MUCH WEAKER NORTHERN STREAM SHORTWAVE...WHICH WILL BE
DIGGING ACROSS THE LOWER LAKES IN THE EVENING AND WILL EVENTUALLY
PHASE WITH THE FIRST SYSTEM OVERNIGHT. THE DEEPER MOISTURE
ASSOCIATED WITH THIS SECOND FEATURE WILL BE BEHIND THE MID LEVEL
SHORTWAVE AND CLOSER TO A WEAK LOW LEVEL TROUGH. THIS MAY TOUCH OFF
A FEW MORE SHOWERS OVERNIGHT INTO FRIDAY MORNING AS IT CROSSES THE
REGION...BUT THEY SHOULD BE WIDELY SCATTERED AND LIGHT IN NATURE.
BY FRIDAY AFTERNOON DEEPER MOISTURE AND LIFT WITH THIS SECOND WAVE
WILL MOVE SOUTHEAST OF THE AREA...WITH A MUCH DRIER AIRMASS
ADVECTING INTO THE LOWER LAKES DURING THE AFTERNOON. ANY LEFTOVER
SCATTERED SHOWERS THROUGH MIDDAY WILL END FROM NORTHWEST TO
SOUTHEAST DURING THE AFTERNOON WITH CLEARING SKIES LATE IN THE DAY.
FRIDAY NIGHT INTO SATURDAY HIGH PRESSURE WILL BUILD INTO THE GREAT
LAKES AND OHIO VALLEY. THIS WILL BRING A RETURN TO DRY AND CLEAR
WEATHER...AND ALSO DELIVER A COOLER/DRIER AIRMASS INTO THE REGION.
LOWS WILL BE ON THE COOL SIDE FRIDAY NIGHT WITH LOWER 50S ON THE
LAKE PLAINS AND 40S IN THE INTERIOR SOUTHERN TIER AND EAST OF LAKE
ONTARIO. AFTER A COOL START...SATURDAY WILL WARM NICELY UNDER FULL
SUNSHINE WITH 850MB TEMPS AROUND +9C. THIS SHOULD SUPPORT HIGHS IN
THE LOWER TO MID 70S AT LOWER ELEVATIONS. THE WEAK SYNOPTIC SCALE
PRESSURE GRADIENT AND STRONG DIFFERENTIAL HEATING WILL SUPPORT LAKE
BREEZE DEVELOPMENT WITH COOLER TEMPS ALONG THE LAKESHORES.
SATURDAY NIGHT HIGH PRESSURE WILL BEGIN TO DRIFT TO THE EASTERN
SEABOARD...WITH SOUTHWEST RETURN FLOW BEGINNING. THIS WILL HELP KEEP
LOWS A LITTLE MORE MILD THAN FRIDAY NIGHT ESPECIALLY ACROSS WESTERN
NY. INCREASING WARM ADVECTION AND ISENTROPIC UPGLIDE WILL BRING SOME
INCREASE IN CLOUDS FROM WEST TO EAST OVERNIGHT.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
BY SUNDAY THE RIDGE ACROSS THE CENTRAL CONUS WILL BEGIN TO BREAK
DOWN AS FLOW BECOMES ZONAL AGAIN OVER THE NORTHERN TIER OF THE
NATION. THIS WILL ALLOW A SERIES OF WEAK AND FAST MOVING SHORTWAVES
TO MOVE THROUGH THE GREAT LAKES REGION. THE 12Z GFS AND ECMWF HAVE
COME INTO A LITTLE BETTER AGREEMENT TODAY WITH RESPECT TO SUNDAY...
AS BOTH MOVE THE FIRST SHORTWAVE INTO THE LOWER LAKES DURING THE
DAY. THIS MAY TOUCH OF A FEW SCATTERED SHOWERS AND THUNDERSTORMS
DURING THE AFTERNOON...ALTHOUGH IT LOOKS LIKE COVERAGE WILL REMAIN
SPARSE. THE NEXT IN A SERIES OF SHORTWAVES WILL CROSS THE AREA
MONDAY OR MONDAY NIGHT WITH A CHANCE OF A FEW MORE SHOWERS AND
STORMS...ALTHOUGH TIMING OF INDIVIDUAL WAVES IS UNCERTAIN AT THIS
TIME RANGE.
BY TUESDAY AND WEDNESDAY MODEL UNCERTAINTY BEGINS TO INCREASE AS THE
ECMWF HANGS ONTO MORE OF A TROUGH AND DEEPER MOISTURE ACROSS THE
GREAT LAKES. THIS WOULD ALLOW AT LEAST A LOW CHANCE OF SHOWERS AND A
FEW THUNDERSTORMS TO LINGER TUESDAY AND WEDNESDAY. THE GFS ON THE
OTHER HAND PUSHES THE TROUGH A LITTLE FARTHER EAST...WITH HIGH
PRESSURE BUILDING INTO THE GREAT LAKES LATER TUESDAY AFTERNOON AND
WEDNESDAY. FOR NOW WILL STICK CLOSE TO PREVIOUS FORECAST CONTINUITY
WITH A LOW CHANCE ON TUESDAY THEN DRY ON WEDNESDAY UNTIL BETTER
MODEL AGREEMENT IS REACHED.
TEMPERATURES WILL WARM TO A LITTLE ABOVE AVERAGE BY SUNDAY AND
MONDAY AS A WARMER AIRMASS MOVES INTO THE AREA FROM THE MIDWEST. IF
THE MORE PROGRESSIVE GFS VERIFIES...TEMPERATURES WOULD COOL BACK TO
AVERAGE AS HIGH PRESSURE BUILDS INTO THE GREAT LAKES.
&&
.AVIATION /20Z WEDNESDAY THROUGH MONDAY/...
VFR CONDITIONS WILL CONTINUE AREA-WIDE THROUGH THIS EVENING AS WEAK
HIGH PRESSURE BUILDS ACROSS NEW YORK STATE.
AFTER THIS...THE FORECAST WILL DEPEND ON THE EVOLUTION OF A STRONG
CONVECTIVE COMPLEX WHICH IS FORECAST TO DEVELOP ACROSS THE MID-
WEST AND TRACK ESE ACROSS PENNSYLVANIA. AS THE COMPLEX STRENGTHENS
LATE THIS EVENING...IT WILL LIKELY CURVE TO THE RIGHT PUSHING IT
SOUTHWARD WHERE THE MORE UNSTABLE AIR LIES. GIVEN THIS
LIKELIHOOD...EXPECT ONLY A MINIMAL IMPACT ON ALL OF OUR TAF SITES
WITH THE EXCEPTION OF JHW...WHICH WILL LIKELY CATCH THE NORTHERN
FRINGE OF THE ASSOCIATED PRECIPITATION SHIELD. THIS SAID...THERE
IS A SLIGHT CHANCE THIS COMPLEX WILL TRACK NORTH OF THIS
FORECAST...AND IF IT DOES IT WOULD HAVE A SIGNIFICANT IMPACT ON
THE BUF/IAG/ROC TERMINALS.
ON THURSDAY...THE CONVECTIVE COMPLEX AND ASSOCIATED LOW PRESSURE
WILL EXIT EAST...WITH A DEVELOPING NE FLOW. THIS WILL LIKELY LOWER
CIGS...BUT PROBABLY STILL JUST ABOVE 3000 FT IN THE VFR CATEGORY.
OUTLOOK...
THURSDAY NIGHT AND FRIDAY...MVFR/VFR WITH A CHANCE OF SHOWERS.
SATURDAY AND SUNDAY...MAINLY VFR.
&&
.MARINE...
LOW PRESSURE WILL PASS JUST TO THE SOUTH OF THE LOWER LAKES TONIGHT
AND THURSDAY...WITH WINDS INITIALLY INCREASING OUT OF THE
EAST...THEN BACKING TO NORTH DURING THURSDAY. AT THIS POINT...IT
STILL APPEARS THAT WINDS AND WAVES MAY INCREASE JUST ENOUGH TO
EVENTUALLY WARRANT SMALL CRAFT ADVISORIES FOR WESTERN LAKE ONTARIO
AND LAKE ERIE.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...APFFEL
NEAR TERM...APFFEL
SHORT TERM...HITCHCOCK
LONG TERM...AR/HITCHCOCK
AVIATION...APFFEL
MARINE...APFFEL/HITCHCOCK
AREA FORECAST DISCUSSION
NWS BUFFALO NY
210 PM EDT WED JUN 12 2013
.SYNOPSIS...
LOW PRESSURE WILL TRACK ACROSS PENNSYLVANIA TONIGHT AND
THURSDAY. THIS WILL BRING A ROUND OF SHOWERS AND THUNDERSTORMS TO
THE SOUTHERN TIER LATE TONIGHT...AND POSSIBLY A SHOWERS ELSEWHERE
ON THURSDAY. AFTER THIS...HIGH PRESSURE WILL BUILD ACROSS THE
REGION...BRINGING A RETURN TO FAIR WEATHER LATE FRIDAY AND
SATURDAY.
&&
.NEAR TERM /THROUGH THURSDAY/...
OUR MAIN FORECAST FOCUS WILL BE THE EXPECTED DEVELOPMENT OF A
SIGNIFICANT CONVECTIVE COMPLEX ACROSS THE MID-WESTERN STATES LATER
TODAY. 12Z GUIDANCE HAS ALL TRENDED SOUTHWARD WITH THE TRACK OF
THIS...WHICH IS CONSISTENT WITH OUR FORECAST PHILOSOPHY THAT THE
MCS WILL LIKELY VEER TO THE RIGHT (SOUTHWARD) TOWARD THE MORE
UNSTABLE AIR. BECAUSE OF THIS...HAVE BEEN ABLE TO TIGHTEN THE POP
GRADIENT...RESULTING IN A DRIER FORECAST BUFFALO-ROCHESTER
NORTHWARD...WHILE CONFIDENCE REMAINS HIGH IN A PERIOD OF RAIN
SHOWERS NEAR THE NY/PA LINE. OUR REGION WILL BE ON THE NORTHERN
FRINGE OF THE COMPLEX...A SECTOR WHICH IS LESS LIKELY TO HAVE ANY
SEVERE WEATHER ASSOCIATED WITH IT. THE RGEM CONTINUES TO BE A
NORTHWARD OUTLIER AMONG MODEL GUIDANCE...SUGGESTING THERE IS A
SMALL BUT DIMINISHING CHANCE OF A MORE NORTHWARD TRACK WHICH WOULD
BRING HEAVIER RAINS INTO WESTERN NEW YORK.
FOR THE REMAINDER OF THIS AFTERNOON...IT SHOULD CONTINUE TO BE
QUITE PLEASANT...WITH PARTLY TO MOSTLY SUNNY SKIES ACROSS WESTERN
NEW YORK AND TEMPERATURES MAINLY IN THE 70S. RADAR SHOWS A FEW
LIGHT SHOWERS STREAMING ACROSS NE OHIO AND EASTERN MICHIGAN...BUT
THESE ARE LIKELY TO REMAIN JUST SOUTH OF OUR REGION.
GIVEN SUPPORT FROM THE NAM/GFS/SREF...FEEL THE HRRR WILL BE ABLE
TO MOST EFFECTIVELY CAPTURE THIS FEATURE...AND SHOULD HAVE GOOD
SKILL ADVECTING THE COMPLEX ONCE IT FULLY DEVELOPS. THERE MAY BE
AN INITIAL ROUND OF THUNDERSTORMS WHICH SHOULD TRACK ACROSS
WESTERN PENNSYLVANIA THIS EVENING. THE MAIN COMPLEX IS FORECAST
TO REACH CENTRAL LAKE ERIE SHORTLY AFTER MIDNIGHT...WITH ANY
IMPACTS TO OUR REGION LIKELY TO HOLD OFF UNTIL AFTER 3 AM. THIS
SHOULD PASS SOUTH BUT CLIP THE SOUTHERN TIER DURING THE EARLY
MORNING HOURS...THROUGH MID-MORNING. EXPECT PERIOD OF MODERATE
TO HEAVY RAIN...WITH SOME EMBEDDED THUNDERSTORMS POSSIBLE.
ON THURSDAY...EXPECT THE COMPLEX TO MAINTAIN STRENGTH AS IT MOVES
ACROSS PENNSYLVANIA. A SECONDARY UPPER LEVEL SHORTWAVE WILL CATCH
UP TO THE FEATURE DURING THE DAY...AND THIS WILL LIKELY ALLOW
ASSOCIATED PRECIPITATION TO SPREAD FURTHER TO THE NORTH. BY THIS
TIME...THE COMPLEX AND ASSOCIATED LOW WILL LIKELY BE ACROSS
EASTERN PENNSYLVANIA...WITH ONLY A MODEST NORTHWARD SPREAD OF
SHOWERS IN EASTERN PORTIONS OF OUR CWA. THIS SHORTWAVE MAY
GENERATE SOME LIGHT SHOWERS ON ITS OWN DURING THE LATE AFTERNOON.
FLOOD POTENTIAL IS COMPLETELY DEPENDENT ON THE TRACK OF THE
COMPLEX. GIVEN THE EXPECTED TRACK...THE HEAVIEST RAIN WOULD REMAIN
SOUTH OF OUR FORECAST AREA. RAINFALL AMOUNTS OF AROUND AN INCH ARE
EXPECTED NEAR THE NY/PA BORDER...WITH THESE LIKELY TO DROP OFF
RAPIDLY NORTHWARD. THERE STILL IS A SLIGHT CHANCE THE HEAVY RAINS
WILL MAKE IT INTO NEW YORK IF SOME OF THE OUTLIER MODEL GUIDANCE
VERIFIES. OBSERVATIONAL TRENDS SHOULD HELP FINE-TUNE THE FORECAST
DURING THE EVENING HOURS. ONE OTHER THING TO NOTE IS THAT SOME OF
OUR BASINS DO EXTEND INTO FAR NORTHERN PENNSYLVANIA. MMEFS
ENSEMBLES SHOW LOW CHANCES FOR FLOODING ON THE ALLEGHENY AT OLEAN
AND THE GENESEE AT WELLSVILLE...MAINLY DUE TO UPSTREAM RAINS. AT
THIS TIME...CONFIDENCE IS WELL BELOW WATCH THRESHOLD...BUT WILL
CONTINUE TO MENTION THIS POTENTIAL IN THE HWO.
&&
.SHORT TERM /THURSDAY NIGHT THROUGH FRIDAY NIGHT/...
EVENTUALLY THE LOW PRESSURE SYSTEM WILL MOVE OUT AND EAST OF THE
AREA THURSDAY NIGHT. THIS WILL TAPER THE RAINS OFF FROM WEST TO EAST.
MODELS DO SLOW THE CUTOFF OVER NEW ENGLAND AS A NORTHERN STREAM
SYSTEM PHASE WITH IT WHICH MAY ALLOW SOME SCATTERED SHOWERS TO
LINGER ACROSS THE REGION EARLY FRIDAY. THIS SYSTEM LOOK TO LIFT OUT
LATER FRIDAY ALLOWING HIGH PRESSURE AND DRIER AIR TO BUILD INTO THE
REGION.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
ON SATURDAY HIGH PRESSURE WILL BUILD ACROSS THE GREAT LAKES AND
FINALLY PROVIDE A RETURN TO SUNSHINE AND LOWER HUMIDITY. AFTER A
COOL START TEMPERATURES WILL REBOUND TO WITHIN A FEW DEGREES OF
AVERAGE.
BY SUNDAY MODEL GUIDANCE BEGINS TO DIVERGE ONCE AGAIN. THE GFS HAS
TRENDED FASTER WITH THE NEXT SYSTEM AS IT QUICKLY BREAKS DOWN THE
UPSTREAM RIDGE OVER THE MIDWEST. THIS WOULD BRING SHOWER AND
THUNDERSTORM CHANCES BACK INTO THE AREA AS EARLY AS SUNDAY. THE
ECMWF REMAINS A LITTLE SLOWER...WITH BETTER RAIN CHANCES HOLDING OFF
UNTIL SUNDAY NIGHT AND MONDAY. FOR NOW WILL GO WITH THE SLOWER ECMWF
SOLUTION...ALTHOUGH IF THE GFS TREND CONTINUES LATER FORECASTS MAY
NEED TO INTRODUCE RAIN CHANCES FOR SUNDAY.
BY NEXT WEEK BOTH THE GFS AND ECMWF CONTINUE THE PROGRESSIVE
NORTHWEST FLOW ALONG THE US/CANADIAN BORDER WITH NUMEROUS SHORTWAVES
TRAVERSING THE NORTHWEST FLOW. TIMING AGREEMENT COMPLETELY BREAKS
DOWN BY TUESDAY AMONGST VARIOUS MEDIUM RANGE OPERATIONAL AND
ENSEMBLE GUIDANCE. WITH THIS IN MIND WILL JUST CONTINUE WITH THE LOW
CHANCE POPS THROUGH TUESDAY UNTIL BETTER TIMING AGREEMENT CAN BE
ACHIEVED IN MODEL GUIDANCE. TEMPERATURES WILL REMAIN VERY CLOSE TO
AVERAGE THROUGH THE PERIOD.
&&
.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
VFR CONDITIONS WILL CONTINUE AREA-WIDE THROUGH THIS EVENING AS WEAK
HIGH PRESSURE BUILDS ACROSS NEW YORK STATE.
AFTER THIS...THE FORECAST WILL DEPEND ON THE EVOLUTION OF A STRONG
CONVECTIVE COMPLEX WHICH IS FORECAST TO DEVELOP ACROSS THE MID-
WEST AND TRACK ESE ACROSS PENNSYLVANIA. AS THE COMPLEX STRENGTHENS
LATE THIS EVENING...IT WILL LIKELY CURVE TO THE RIGHT PUSHING IT
SOUTHWARD WHERE THE MORE UNSTABLE AIR LIES. GIVEN THIS
LIKELIHOOD...EXPECT ONLY A MINIMAL IMPACT ON ALL OF OUR TAF SITES
WITH THE EXCEPTION OF JHW...WHICH WILL LIKELY CATCH THE NORTHERN
FRINGE OF THE ASSOCIATED PRECIPITATION SHIELD. THIS SAID...THERE
IS A SLIGHT CHANCE THIS COMPLEX WILL TRACK NORTH OF THIS
FORECAST...AND IF IT DOES IT WOULD HAVE A SIGNIFICANT IMPACT ON
THE BUF/IAG/ROC TERMINALS.
ON THURSDAY...THE CONVECTIVE COMPLEX AND ASSOCIATED LOW PRESSURE
WILL EXIT EAST...WITH A DEVELOPING NE FLOW. THIS WILL LIKELY LOWER
CIGS...BUT PROBABLY STILL JUST ABOVE 3000 FT IN THE VFR CATEGORY.
OUTLOOK...
THURSDAY NIGHT AND FRIDAY...MVFR/VFR WITH A CHANCE OF SHOWERS.
SATURDAY AND SUNDAY...MAINLY VFR.
&&
.MARINE...
LIGHT AND VARIABLE WINDS THIS MORNING WITH THE PRESSURE GRADIENT
OVER THE LOWER LAKES WEAKENING. LAKE BREEZES SHOULD DEVELOP THIS
AFTERNOON GIVEN THE WEAK OVERALL GRADIENT.
LOOKING A LITTLE FURTHER AHEAD...ANOTHER REGION OF LOW PRESSURE WILL
PASS JUST TO THE SOUTH OF THE LOWER LAKES TONIGHT AND
THURSDAY...WITH WINDS INITIALLY INCREASING OUT OF THE EAST...THEN
BACKING TO NORTH DURING THURSDAY. AT THIS POINT...IT STILL APPEARS
THAT WINDS AND WAVES MAY INCREASE JUST ENOUGH TO EVENTUALLY WARRANT
SMALL CRAFT ADVISORIES FOR WESTERN LAKE ONTARIO AND LAKE ERIE.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...APFFEL
NEAR TERM...APFFEL
SHORT TERM...TMA
LONG TERM...HITCHCOCK
AVIATION...APFFEL
MARINE...JJR/SMITH/APFFEL
AREA FORECAST DISCUSSION
NWS RALEIGH NC
315 PM EDT WED JUN 12 2013
.SYNOPSIS...
A LOW PRESSURE SYSTEM AND ASSOCIATED COLD FRONT WILL PROGRESS FROM
THE CENTRAL PLAINS INTO THE OHIO VALLEY TONIGHT...THEN MOVE ACROSS
THE MID ATLANTIC AND CAROLINAS ON THURSDAY AFTERNOON AND EVENING. A
COOLER AND DRIER AIR MASS WILL BUILD INTO THE REGION BEHIND THE COLD
FRONT FOR FRIDAY AND SATURDAY.
&&
.NEAR TERM /THIS AFTERNOON AND TONIGHT/...
AS OF 250 PM WEDNESDAY...
LATEST SFC ANALYSIS SHOWS COLD FRONT EXTENDED FROM NEAR KORD EAST
AND SOUTHEAST INTO THE NORTHERN CHESAPEAKE BAY. A BROAD SFC TROUGH
HAS SET UP OVER THE WESTERN CAROLINAS WITH A LIGHT SOUTHWESTERLY
SURFACE FLOW. SURFACE DEWPOINTS RANGE IN THE UPPER 60S IN THE
WESTERN PIEDMONT TO MID 60S FURTHER EAST WITH TEMPERATURES IN THE
UPPER 80S TO NEAR 90. THE AIR MASS IN THE WESTERN PIEDMONT IS
STRONGLY UNSTABLE WITH MLCAPE VALUES EXCEEDING 3000 J/KG WITH A
MODERATELY UNSTABLE AIRMASS FURTHER EAST.
WE HAVE BEEN CONCERNED ABOUT THE POTENTIAL FOR CONVECTION TO DEVELOP
IN OR UPSTREAM OF THIS AIRMASS AND THEN MOVE ACROSS CENTRAL NC. A
DISTURBANCE IN THE NW FLOW ALOFT MOVED THROUGH CENTRAL NC LATE THIS
MORNING WITH SOME BRIEF RIDGING ALOFT THIS AFTERNOON BEFORE ANOTHER
DISTURBANCE MOVES ACROSS SOUTHEAST VA AND NORTHEAST NC LATER THIS
EVENING. THE NAM AND TO A LESSER EXTENT RAP BUFR SOUNDINGS HAVE
NOTED A LOW LEVEL CAP THAT SHOULD LIMIT CONVECTIVE COVERAGE.
CONVECTION ALLOWING MODELS HAVE STRUGGLED WITH THE POTENTIAL FOR
CONVECTION TODAY GIVEN THE WEAKER FORCING AND MORE SUBTLE FEATURES.
THEY CURRENTLY PROVIDE A VARIETY OF SOLUTIONS THIS EVENING BUT THEIR
TREND IS FOR LESS COVERAGE WITH THE GREATEST CHANCE IN THE WESTERN
PIEDMONT THIS EVENING. WILL INCLUDE SLIGHT CHANCE POPS IN THE WEST
THIS EVENING BUT KEEP THE REST OF THE AREA DRY WITH FAIR SKIES.
EXPECT LOWS OVERNIGHT IN THE 68 TO 73 RANGE. -BLAES
&&
.SHORT TERM /THURSDAY AND THURSDAY NIGHT/...
AS OF 315 PM WEDNESDAY...
...SEVERE WEATHER POSSIBLE LATE THURSDAY AFTERNOON AND EVENING...
A ROBUST SHORT WAVE TROUGH WILL MOVE ACROSS THE OHIO VALLEY ON
THURSDAY AND OFF THE MID ATLANTIC COAST ON THURSDAY EVENING. THE
ASSOCIATED SURFACE LOW WILL DEEPEN AS IT MOVES ACROSS THE
APPALACHIANS INTO THE NORTHERN CHESAPEAKE BAY AS THE TRAILING COLD
FRONT SLIDES ACROSS CENTRAL NC. THE AIR MASS AHEAD OF THE FRONT IS
EXPECTED TO BE MODERATELY TO NEARLY STRONGLY UNSTABLE WITH MID-LEVEL
LAPSE RATES OF AROUND 7 DEG C/KM. EXPECT A STOUT SOUTHWEST TO
WESTERLY LOW LEVEL FLOW DURING THE AFTERNOON WITH STRONGER MID LEVEL
WIND MAX OF 50+ KTS ROTATING INTO THE REGION. EXPECT ISOLATED
CONVECTION TO FIRE ACROSS THE WESTERN PIEDMONT DURING THE MID
AFTERNOON...INITIATED IN PART BY THE APPROACHING SFC TROUGH BUT
LIMITED IN COVERAGE FROM A NOTABLE DOWNSLOPE DRYING FLOW OFF THE
MOUNTAINS. CONVECTION IS LIKELY TO INTENSIFY AND SLOWLY GROW IN
COVERAGE AS IT APPROACHES THE US 1 CORRIDOR DURING THE LATE
AFTERNOON IN THE FORM OF ORGANIZED CONVECTION INCLUDING POSSIBLE
SUPERCELLS WITH DAMAGING WINDS AND POSSIBLY HAIL. AS THE CONVECTION
REACHES A MORE MOIST ENVIRONMENT THE CONVECTION WILL LIKELY GROW
UPSCALE INTO A SQUALL LINE AND BOWING FEATURE AS IT MOVES ACROSS THE
COASTAL PLAIN WITH THE POTENTIAL FOR WIDESPREAD DAMAGING WINDS. THE
GREATEST THREAT OF SEVERE WEATHER WILL LIKELY BE IN THE COASTAL
PLAIN BETWEEN 4 AND 9 WITH WIDESPREAD DAMAGING WINDS POSSIBLE.
HIGH TEMPERATURES ARE EXPECTED TO CLIMB INTO LOWER 90S NORTHWEST TO
MID 90S SOUTHEAST. THESE TEMPERATURES COMBINED WITH DEWPOINTS IN THE
MID TO POSSIBLY UPPER 60S WILL RESULT IN HEAT INDEX VALUES AROUND OR
JUST EXCEEDING 100 DEGREES. WILL ACCORDINGLY MENTION THIS IN THE
HWO. BEHIND THE COLD FRONT...LOW TEMPERATURES WILL FALL INTO THE
LOWER TO MID 60S BY FRIDAY MORNING. -BLAES
&&
.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
AS OF 240 PM WEDNESDAY...
CONDITIONS WILL DRY OUT AND COOL DOWN BEHIND THE DEPARTING SYSTEM
FOR THE END OF THE WORK WEEK AND EARLY WEEKEND. THE STRONG MID/UPPER
LEVEL TROUGH WILL BE CROSSING THE AREA DURING THE DAY ON FRIDAY AND
VERY WELL COULD PRODUCE A COUPLE OF SHOWERS OR SOME SPRINKLES.
HOWEVER...THE DEEP MOISTURE WILL HAVE MOVED OFFSHORE...SO AM NOT
EXPECTING ENOUGH COVERAGE TO PUT ANY MENTION IN THE FORECAST. IF
ANYTHING DOES DEVELOP...IT SHOULD BE ACROSS THE EASTERN THIRD OF THE
FORECAST AREA WHERE SOME RESIDUAL MOISTURE (PWAT VALUES NEAR AN
INCH) MAY RESIDE.
THEN...SURFACE HIGH PRESSURE AND RISING HEIGHTS ALOFT (ALTHOUGH THE
CORE OF THE MID/UPPER HIGH WILL REMAIN WEST OF OF THE REGION BEFORE
FLATTENING OUT BY THE LATTER HALF OF THE WEEKEND) WILL LEAD TO MORE
SUNSHINE AND MOSTLY DRY CONDITIONS THROUGH MUCH OF THE WEEKEND.
TEMPS SHOULD STAY BELOW NORMAL (HIGHS IN THE LOW/MID 80S...OVERNIGHT
LOWS IN THE LOW 60S...WITH EVEN SOME UPPER 50S POSSIBLE) FRIDAY AND
SATURDAY...BEFORE MODIFYING ON SUNDAY AS THE SURFACE HIGH SHIFTS
OFFSHORE. THE NEXT SYSTEM LOOKS TO APPROACH THE REGION EARLY NEXT
WEEK...BUT THERE ARE STILL SOME TIMING/STRENGTH ISSUES BETWEEN THE
MODELS. AT THIS TIME...IT APPEARS A FRONT WILL MOVE THROUGH THE AREA
SOMETIME ON TUESDAY...WHICH IS WHEN THE BEST CHANCE OF RAIN WILL BE
FOCUSED. HOWEVER...INCREASING SOUTHWESTERLY FLOW WILL DRIVE OUR
MOISTURE BACK UP AND THEREFORE WILL HAVE SLIGHT CHANCE POPS FOR
MONDAY. TEMPS WILL BE NEAR NORMAL FOR THE BEGINNING ON NEXT WEEK.
&&
.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
AS OF 140 PM WEDNESDAY...
VFR CONDITIONS ARE EXPECTED TO PREVAIL THROUGH THE CURRENT TAF
PERIOD. THERE COULD BE AN ISOLATED SHOWER OR THUNDERSTORM THAT
DEVELOPS LATER THIS AFTERNOON...MOST LIKELY ACROSS THE WEST...BUT
CHANCES ARE TOO SMALL TO INCLUDE ANY MENTION IN THE TAFS.
OTHERWISE...SOUTHWESTERLY WINDS WILL INCREASE THURSDAY MORNING...
WITH GUSTS AROUND 25 KNOTS POSSIBLE. IT STILL APPEARS THAT THE
MAJORITY OF THE PRECIP WILL HOLD OFF UNTIL AFTER 18Z THURSDAY.
OUTLOOK...ADVERSE AVIATION CONDITIONS IN THE FORM OF SCATTERED TO
WIDESPREAD SHOWERS AND THUNDERSTORMS ARE EXPECTED DURING THE DAY
THURSDAY...LIKELY BEGINNING SHORTLY AFTER 18Z. ANY THUNDERSTORMS
THAT DEVELOP WILL BE CAPABLE OF PRODUCING DAMAGING SURFACE WIND
GUSTS IN EXCESS OF 50 KNOTS. AT THIS TIME...THE BEST CHANCE FOR
AFTERNOON CONVECTION AND SEVERE WEATHER WILL BE AT THE RDU/FAY/RWI
TERMINALS. GUSTY SOUTHWESTERLY WINDS (SEE ABOVE PARAGRAPH) WILL
SHIFT TO THE NORTHWEST IN THE WAKE OF A COLD FRONTAL PASSAGE
THURSDAY EVENING/NIGHT. EXPECT DRY/VFR CONDITIONS TO PREVAIL IN THE
WAKE OF THE FRONT FRIDAY THROUGH THE WEEKEND...WITH THE NEXT CHANCE
OF PRECIP RETURNING TO THE AREA EARLY NEXT WEEK.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...BLAES
NEAR TERM...BLAES
SHORT TERM...BLAES
LONG TERM...KRR
AVIATION...KRR/VINCENT
AREA FORECAST DISCUSSION
NWS RALEIGH NC
322 PM EDT WED JUN 12 2013
.SYNOPSIS...
A LOW PRESSURE SYSTEM AND ASSOCIATED COLD FRONT WILL PROGRESS FROM
THE CENTRAL PLAINS INTO THE OHIO VALLEY TONIGHT...THEN MOVE ACROSS
THE MID ATLANTIC AND CAROLINAS ON THURSDAY AFTERNOON AND EVENING. A
COOLER AND DRIER AIR MASS WILL BUILD INTO THE REGION BEHIND THE COLD
FRONT FOR FRIDAY AND SATURDAY.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
AS OF 250 PM WEDNESDAY...
LATEST SFC ANALYSIS SHOWS COLD FRONT EXTENDED FROM NEAR KORD EAST
AND SOUTHEAST INTO THE NORTHERN CHESAPEAKE BAY. A BROAD SFC TROUGH
HAS SET UP OVER THE WESTERN CAROLINAS WITH A LIGHT SOUTHWESTERLY
SURFACE FLOW. SURFACE DEWPOINTS RANGE IN THE UPPER 60S IN THE
WESTERN PIEDMONT TO MID 60S FURTHER EAST WITH TEMPERATURES IN THE
UPPER 80S TO NEAR 90. THE AIR MASS IN THE WESTERN PIEDMONT IS
STRONGLY UNSTABLE WITH MLCAPE VALUES EXCEEDING 3000 J/KG WITH A
MODERATELY UNSTABLE AIRMASS FURTHER EAST.
WE HAVE BEEN CONCERNED ABOUT THE POTENTIAL FOR CONVECTION TO DEVELOP
IN OR UPSTREAM OF THIS AIRMASS AND THEN MOVE ACROSS CENTRAL NC. A
DISTURBANCE IN THE NW FLOW ALOFT MOVED THROUGH CENTRAL NC LATE THIS
MORNING WITH SOME BRIEF RIDGING ALOFT THIS AFTERNOON BEFORE ANOTHER
DISTURBANCE MOVES ACROSS SOUTHEAST VA AND NORTHEAST NC LATER THIS
EVENING. THE NAM AND TO A LESSER EXTENT RAP BUFR SOUNDINGS HAVE
NOTED A LOW LEVEL CAP THAT SHOULD LIMIT CONVECTIVE COVERAGE.
CONVECTION ALLOWING MODELS HAVE STRUGGLED WITH THE POTENTIAL FOR
CONVECTION TODAY GIVEN THE WEAKER FORCING AND MORE SUBTLE FEATURES.
THEY CURRENTLY PROVIDE A VARIETY OF SOLUTIONS THIS EVENING BUT THEIR
TREND IS FOR LESS COVERAGE WITH THE GREATEST CHANCE IN THE WESTERN
PIEDMONT THIS EVENING. WILL INCLUDE SLIGHT CHANCE POPS IN THE WEST
THIS EVENING BUT KEEP THE REST OF THE AREA DRY WITH FAIR SKIES.
EXPECT LOWS OVERNIGHT IN THE 68 TO 73 RANGE. -BLAES
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH THURSDAY NIGHT/...
AS OF 315 PM WEDNESDAY...
SEVERE WEATHER POSSIBLE LATE THURSDAY AFTERNOON AND EVENING...
A ROBUST SHORT WAVE TROUGH WILL MOVE ACROSS THE OHIO VALLEY ON
THURSDAY AND OFF THE MID ATLANTIC COAST ON THURSDAY EVENING. THE
ASSOCIATED SURFACE LOW WILL DEEPEN AS IT MOVES ACROSS THE
APPALACHIANS INTO THE NORTHERN CHESAPEAKE BAY AS THE TRAILING COLD
FRONT SLIDES ACROSS CENTRAL NC. THE AIR MASS AHEAD OF THE FRONT IS
EXPECTED TO BE MODERATELY TO NEARLY STRONGLY UNSTABLE WITH MID-LEVEL
LAPSE RATES OF AROUND 7 DEG C/KM. EXPECT A STOUT SOUTHWEST TO
WESTERLY LOW LEVEL FLOW DURING THE AFTERNOON WITH STRONGER MID LEVEL
WIND MAX OF 50+ KTS ROTATING INTO THE REGION. EXPECT ISOLATED
CONVECTION TO FIRE ACROSS THE WESTERN PIEDMONT DURING THE MID
AFTERNOON...INITIATED IN PART BY THE APPROACHING SFC TROUGH BUT
LIMITED IN COVERAGE FROM A NOTABLE DOWNSLOPE DRYING FLOW OFF THE
MOUNTAINS. CONVECTION IS LIKELY TO INTENSIFY AND SLOWLY GROW IN
COVERAGE AS IT APPROACHES THE US 1 CORRIDOR DURING THE LATE
AFTERNOON IN THE FORM OF ORGANIZED CONVECTION INCLUDING POSSIBLE
SUPERCELLS WITH DAMAGING WINDS AND POSSIBLY HAIL. AS THE CONVECTION
REACHES A MORE MOIST ENVIRONMENT THE CONVECTION WILL LIKELY GROW
UPSCALE INTO A SQUALL LINE AND BOWING FEATURE AS IT MOVES ACROSS THE
COASTAL PLAIN WITH THE POTENTIAL FOR WIDESPREAD DAMAGING WINDS. THE
GREATEST THREAT OF SEVERE WEATHER WILL LIKELY BE IN THE COASTAL
PLAIN BETWEEN 4 AND 9 WITH WIDESPREAD DAMAGING WINDS POSSIBLE.
HIGH TEMPERATURES ARE EXPECTED TO CLIMB INTO LOWER 90S NORTHWEST TO
MID 90S SOUTHEAST. THESE TEMPERATURES COMBINED WITH DEWPOINTS IN THE
MID TO POSSIBLY UPPER 60S WILL RESULT IN HEAT INDEX VALUES AROUND OR
JUST EXCEEDING 100 DEGREES. WILL ACCORDINGLY MENTION THIS IN THE
HWO. BEHIND THE COLD FRONT...LOW TEMPERATURES WILL FALL INTO THE
LOWER TO MID 60S BY FRIDAY MORNING. -BLAES
&&
.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
AS OF 240 PM WEDNESDAY...
CONDITIONS WILL DRY OUT AND COOL DOWN BEHIND THE DEPARTING SYSTEM
FOR THE END OF THE WORK WEEK AND EARLY WEEKEND. THE STRONG MID/UPPER
LEVEL TROUGH WILL BE CROSSING THE AREA DURING THE DAY ON FRIDAY AND
VERY WELL COULD PRODUCE A COUPLE OF SHOWERS OR SOME SPRINKLES.
HOWEVER...THE DEEP MOISTURE WILL HAVE MOVED OFFSHORE...SO AM NOT
EXPECTING ENOUGH COVERAGE TO PUT ANY MENTION IN THE FORECAST. IF
ANYTHING DOES DEVELOP...IT SHOULD BE ACROSS THE EASTERN THIRD OF THE
FORECAST AREA WHERE SOME RESIDUAL MOISTURE (PWAT VALUES NEAR AN
INCH) MAY RESIDE.
THEN...SURFACE HIGH PRESSURE AND RISING HEIGHTS ALOFT (ALTHOUGH THE
CORE OF THE MID/UPPER HIGH WILL REMAIN WEST OF OF THE REGION BEFORE
FLATTENING OUT BY THE LATTER HALF OF THE WEEKEND) WILL LEAD TO MORE
SUNSHINE AND MOSTLY DRY CONDITIONS THROUGH MUCH OF THE WEEKEND.
TEMPS SHOULD STAY BELOW NORMAL (HIGHS IN THE LOW/MID 80S...OVERNIGHT
LOWS IN THE LOW 60S...WITH EVEN SOME UPPER 50S POSSIBLE) FRIDAY AND
SATURDAY...BEFORE MODIFYING ON SUNDAY AS THE SURFACE HIGH SHIFTS
OFFSHORE. THE NEXT SYSTEM LOOKS TO APPROACH THE REGION EARLY NEXT
WEEK...BUT THERE ARE STILL SOME TIMING/STRENGTH ISSUES BETWEEN THE
MODELS. AT THIS TIME...IT APPEARS A FRONT WILL MOVE THROUGH THE AREA
SOMETIME ON TUESDAY...WHICH IS WHEN THE BEST CHANCE OF RAIN WILL BE
FOCUSED. HOWEVER...INCREASING SOUTHWESTERLY FLOW WILL DRIVE OUR
MOISTURE BACK UP AND THEREFORE WILL HAVE SLIGHT CHANCE POPS FOR
MONDAY. TEMPS WILL BE NEAR NORMAL FOR THE BEGINNING ON NEXT WEEK.
&&
.AVIATION /20Z WEDNESDAY THROUGH MONDAY/...
AS OF 140 PM WEDNESDAY...
VFR CONDITIONS ARE EXPECTED TO PREVAIL THROUGH THE CURRENT TAF
PERIOD. THERE COULD BE AN ISOLATED SHOWER OR THUNDERSTORM THAT
DEVELOPS LATER THIS AFTERNOON...MOST LIKELY ACROSS THE WEST...BUT
CHANCES ARE TOO SMALL TO INCLUDE ANY MENTION IN THE TAFS.
OTHERWISE...SOUTHWESTERLY WINDS WILL INCREASE THURSDAY MORNING...
WITH GUSTS AROUND 25 KNOTS POSSIBLE. IT STILL APPEARS THAT THE
MAJORITY OF THE PRECIP WILL HOLD OFF UNTIL AFTER 18Z THURSDAY.
OUTLOOK...ADVERSE AVIATION CONDITIONS IN THE FORM OF SCATTERED TO
WIDESPREAD SHOWERS AND THUNDERSTORMS ARE EXPECTED DURING THE DAY
THURSDAY...LIKELY BEGINNING SHORTLY AFTER 18Z. ANY THUNDERSTORMS
THAT DEVELOP WILL BE CAPABLE OF PRODUCING DAMAGING SURFACE WIND
GUSTS IN EXCESS OF 50 KNOTS. AT THIS TIME...THE BEST CHANCE FOR
AFTERNOON CONVECTION AND SEVERE WEATHER WILL BE AT THE RDU/FAY/RWI
TERMINALS. GUSTY SOUTHWESTERLY WINDS (SEE ABOVE PARAGRAPH) WILL
SHIFT TO THE NORTHWEST IN THE WAKE OF A COLD FRONTAL PASSAGE
THURSDAY EVENING/NIGHT. EXPECT DRY/VFR CONDITIONS TO PREVAIL IN THE
WAKE OF THE FRONT FRIDAY THROUGH THE WEEKEND...WITH THE NEXT CHANCE
OF PRECIP RETURNING TO THE AREA EARLY NEXT WEEK.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...BLAES
NEAR TERM...BLAES
SHORT TERM...BLAES
LONG TERM...KRR
AVIATION...KRR
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
300 PM EDT WED JUN 12 2013
.SYNOPSIS...
HOT TEMPERATURES ARE EXPECTED THIS AFTERNOON AND AGAIN THURSDAY AS
AN UPPER RIDGE MOVES ACROSS THE REGION. A FEW THUNDERSTORMS MAY
DEVELOP INLAND LATE THIS AFTERNOON. MEANWHILE...A RELATIVELY STRONG
COLD FRONT WILL MOVE ACROSS THE AREA THURSDAY NIGHT WITH A GOOD
CHANCE OF STRONG TO SEVERE THUNDERSTORMS. DRY WEATHER IS EXPECTED
INTO THE WEEKEND. ANOTHER COLD FRONT WILL REACH THE CAROLINAS EARLY
NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 245 PM WEDNESDAY...VERY HOT DAY CONTINUES ACROSS THE AREA WITH
MOST LOCATIONS INTO THE LOW 90S...AND SOME MID 90S WELL INLAND. THIS
HAS...IN ESSENCE...CREATED AN ENVIRONMENT FAVORABLE FOR CONVECTION
THIS AFTN. HOWEVER...EVEN WITH AMPLE SURFACE INSTABILITY...EVEN CU
HAS HAD A DIFFICULT TIME DEVELOPING. THIS IS LIKELY DUE TO WARMING
850MB TEMPS...PRODUCING A LID THROUGH WHICH PARCELS ARE STRUGGLING
TO PENETRATE. THIS JIVES WELL WITH PREVIOUS THINKING THAT WARMING IN
THE MID LEVELS WILL SUPPRESS MUCH ACTIVITY TODAY.
LATEST HIGH-RES GUIDANCE IS COMING INTO MUCH BETTER AGREEMENT THAT
CONVECTION OVER THE MOUNTAINS WILL RACE SOUTHWARD AND WEAKEN THIS
EVE/EARLY TONIGHT...REMAINING PRIMARILY WEST OF THE CWA. WILL NOT
COMPLETELY RULE OUT SOME TSTMS CLIPPING THE WESTERN PORTIONS OF THE
AREA BEFORE NOCTURNAL COOLING OCCURS TONIGHT...AND HAVE CONTINUED
SCHC POP FOR THE I-95 COUNTIES AND WEST...BUT ANY ACTIVITY WILL BE
ISOLATED.
AS HIGH PRESSURE REMAINS OFFSHORE TONIGHT AND GRADIENT BEGINS TO
TIGHTEN...SW WINDS WILL INCREASE JUST OFF THE SURFACE...WHICH WILL
KEEP WINDS FROM FULLY DECOUPLING. THIS WILL KEEP TEMPS FROM FALLING
TOO MUCH TONIGHT...AND MINS WILL BE HELD WELL ABOVE NORMAL FOR
MID-JUNE...MID TO UPPER 70S FOR LOWS.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 245 PM WEDNESDAY...TWO SIGNIFICANT ISSUES TO DEAL WITH DURING
THE SHORT TERM PERIOD INCLUDING HIGH HEAT INDICES AND THE POTENTIAL
FOR A SEVERE WEATHER EVENT LATE THURSDAY AFTERNOON AND THURSDAY
EVENING. OVERALL FRIDAY WILL BE A NICE DAY WITH COOLER/NEAR NORMAL
TEMPS AND NO POPS.
AS FOR THURSDAY...HIGH TEMPERATURES RANGING FROM THE MID TO UPPER
90S INLAND TO NEAR 90 COAST COUPLED WITH HIGH HUMIDITY WILL RESULT
IN HEAT INDICES IN THE 99-103F RANGE. FAVORED A BLEND TOWARD THE
WARMER MAV NUMBERS FOR THE INLAND LOCATIONS...ESPECIALLY GIVEN T1
NUMBERS SUGGEST UPPER 90S. HOWEVER...IN REGARDS TO A HEAT ADVISORY
THINK MIXING WILL MOST LIKELY RESULT IN LOWER DEWPOINTS THAN WHAT
GUIDANCE INDICATES...THUS THE FORECAST IS FOR SUB-HEAT ADVISORY
CONDITIONS AT THIS TIME. ALSO NOTE...THE DEWPOINT SENSOR AT
KINGSTREE (KCKI) IS MUCH HIGHER THAN THE SURROUNDING OBS MAKING THE
DATE THERE SUSPECT.
SPC HAS PLACED THE ENTIRE FORECAST AREA IN A SLIGHT RISK FOR
TOMORROW WITH THE OVERALL PROBABILITIES TRENDING HIGHER COMPARED TO
THE PREVIOUS OUTLOOK. A SHORT-WAVE WILL PUSH ACROSS THE MID-ATLANTIC
STATES DURING THE DAY WHILE THE LFQ OF AN UPPER JET BECOMES FOCUSED
ACROSS THE REGION. IN ADDITION...EXPECT AN ABUNDANCE OF INSTABILITY
WITH STRONG HEATING DURING THE DAY. ARW OUTPUT SUGGESTS A SQUALL
LINE PUSHING THROUGH LATER IN THE DAY AND INTO THE EVENING AT THE
COAST. EXPECTING THE PRIMARY THREAT TO BE FROM DAMAGING WINDS.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
AS OF 245 PM WEDNESDAY...AN EAST COAST TROUGH WILL HAVE MOVED WELL
OFFSHORE BY THE START OF THE PERIOD. A LARGE BUBBLE OF HIGH PRESSURE
ALOFT ACROSS THE CENTRAL GULF COAST AND RIDGING NORTHWARD INTO
CANADA WILL BUILD ACROSS THE EASTERN CAROLINAS DURING THE WEEKEND...
BRINGING DRY WEATHER. AT THE SURFACE...HIGH PRESSURE OF CANADIAN
ORIGIN...WILL BUILD OVERHEAD. NORTH WINDS WILL BRING A MUCH DRIER
AND COOLER AIRMASS. THE HIGH WILL SHIFT OFFSHORE ON SUN AND RIDGE
BACK ACROSS THE EASTERN CAROLINAS ON MON...ALLOWING A SOUTHWEST
RETURN FLOW TO DEVELOP WHICH WILL BRING A RETURN TO MORE MUGGY
CONDITIONS AND HIGHER TEMPERATURES.
A SHORTWAVE RIDING OVER THE TOP OF THE RIDGE WILL HELP TO FLATTEN IT
EARLY NEXT WEEK AND THIS WILL HELP DRIVE A COLD FRONT AT THE SURFACE
TOWARD THE SOUTHEAST COAST. BY TUE...THIS FRONT SHOULD BE CLOSE
ENOUGH TO BRING A RISK FOR SHOWERS AND THUNDERSTORMS AS A TROUGH
SLUGGISHLY ATTEMPTS TO BUILD DOWN THE EAST COAST. HIGH PRESSURE MAY
SURGE DOWN THE EAST COAST BY WED NIGHT...HELPING TO DRIVE THE FRONT
THROUGH THE AREA.
PRECIPITABLE WATER VALUES CLIMB FROM LESS THAN AN INCH ON MON TO TWO
INCHES TUE THROUGH WED AS THE DRY AIR IN THE MID LEVELS QUICKLY
ERODES. MIXED LAYER CAPE VALUES ARE EXPECTED TO REACH NEAR 1000 J/KG
AND UP TO 1400 J/KG INLAND TUE AFTERNOON AND ARE A LITTLE HIGHER
ACROSS THE FORECAST AREA ON WED. WILL INCLUDE A LIKELIHOOD FOR
SHOWERS AND THUNDERSTORMS FOR A PORTION OF OUR INLAND ZONES TUE
AFTERNOON AND EVE AS A PRE-FRONTAL TROUGH SHOULD ACT TO FOCUS AND
LIFT THE INCREASING MOISTURE...SCATTERED COVERAGE AS YOU NEAR THE
COAST AND ALONG THE PINNED SEABREEZE BOUNDARY. WILL FAVOR SLIGHTLY
HIGHER POPS AT THE COAST THAN INLAND ON WED...BUT CAP AT HIGH CHANCE
FOR NOW.
TEMPERATURES WILL BE SEASONABLE THROUGH THE PERIOD...MID AND UPPER
80S...BUT KNOCKING ON THE 90 DEGREE DOOR EARLY NEXT WEEK...
ESPECIALLY INLAND. LOWS WILL BE COOLEST SAT NIGHT...MID 60S TO NEAR
70 AT THE COAST. FOR THE REMAINDER OF THE PERIOD...LOWS WILL BE
AROUND 70 TO THE MID 70S AS THE DEWPOINTS CREEP HIGHER.
&&
.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
AS OF 18Z...MODELS ARE NOT IN GOOD AGREEMENT WITH REGARDS TO
CONVECTION THIS AFTERNOON. THE HRRR HAS ABSOLUTELY NOTHING...WHILE
THE WRF AS SCATTERED CONVECTION OVER ABOUT A THIRD OF THE CWA. THINK
THERE WILL BE ISOLATED CB`S...BUT NOT ENOUGH COVERAGE FOR A VCTS
MENTION. SOUTHWEST FLOW WILL BE MORE SOUTH SOUTHWEST AND STRONGER AT
THE COASTAL TERMINALS DUE TO THE RESULTANT. LIGHT WINDS TONIGHT WITH
A REASONABLE CHANCE FOR A COUPLE OF HOURS OF FOG AFTER 09Z.
THURSDAY...CONTINUED SOUTHWEST FLOW WITH MAINLY SCATTERED HIGH
CLOUDS. ANY CONVECTION WILL HOLD OFF UNTIL THE END OF THE FORECAST
VALID PERIOD.
EXTENDED OUTLOOK...ISOLATED SHOWERS/THUNDERSTORMS WITH TEMPO PERIODS
OF MVFR/IFR POSSIBLE THURSDAY EVENING INTO FRIDAY MORNING. MORNING
FOG POSSIBLE SUNDAY AND MONDAY.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 245 PM WEDNESDAY...CONTINUED SW WINDS AROUND OFFSHORE HIGH
PRESSURE WILL KEEP SW WINDS AND A SW WIND CHOP PREDOMINANT OVER THE
WATERS. SEAS CURRENTLY 2-4 FT WILL REMAIN STATUS QUO THROUGH THE
PERIOD...WITH SW WINDS OF 10-15 KTS PERSISTENT. THE EXCEPTION TO
THIS WILL BE WITHIN THE INNER FEW NM IN THE SEA BREEZE
BOUNDARY...WITH A SLIGHTLY BACKING TO SOUTH WILL OCCUR AS WELL AS AN
INCREASE IN SPEEDS...WITH GUSTS UP TO 20 KTS. SEAS WILL REMAIN 2-4
FT IN THIS ZONE...BUT WILL BECOME MORE CHOPPY THANKS TO SHORTER
PERIODS. SEA BREEZE WINDS WILL EASE AFTER SUNSET...ALLOWING FOR
NEAR-SHORE SEAS TO FALL BACK TO AROUND 2 FT INTO THURSDAY MORNING.
SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 245 PM WEDNESDAY...INCREASING SOUTHWESTERLY FLOW THURSDAY WILL
RESULT IN MARGINAL SMALL CRAFT CONDITIONS FOR THE CAPE FEAR WATERS
FROM THE AFTERNOON INTO THE EVENING AHEAD OF AN AREA OF CONVECTION
EXPECTED TO CROSS THE WATERS. PLAN TO HEADLINE SMALL CRAFT SHOULD
EXERCISE CAUTION FOR THE LONG BAY COASTAL WATERS. THE FLOW WILL VEER
TO A NORTHERLY DIRECTION BY FRIDAY MORNING AS HIGH PRESSURE BUILDS
ACROSS THE AREA. SPEEDS WILL FURTHER DIMINISH BY FRIDAY EVENING.
SEAS WILL PEAK AT MARGINAL SMALL CRAFT THRESHOLDS FOR THE OUTER
COASTAL WATERS THURSDAY AFTERNOON AND EVENING...THEN GRADUALLY
SUBSIDE THROUGH THE LATTER HALF OF THE SHORT TERM PERIOD.
LONG TERM /SATURDAY THROUGH MONDAY/...
AS OF 245 PM WEDNESDAY...LIGHT WINDS ON SAT WILL SETTLE ON SOUTH
DURING THE AFTERNOON AND EVE AND BECOME SW ON SUN AS HIGH PRESSURE
MOVES OFFSHORE. SW WINDS WILL CONTINUE FOR THE REMAINDER OF THE
PERIOD...INCREASING LATE MON AND MON NIGHT AS THE PRESSURE GRADIENT
TIGHTENS SLIGHTLY IN RESPONSE TO A DEVELOPING PIEDMONT TROUGH. WINDS
WILL BE 15 KT OR LESS THROUGH THE WEEKEND...HIGHEST LATE DAY AND
THROUGH THE EVE ACROSS THE NEAR SHORE WATERS DUE TO SEABREEZE
INFLUENCES. SW WINDS WILL INCREASE TO AROUND 15 KT THROUGHOUT LATE
MON AND MON NIGHT. SEAS WILL BE 2 TO 3 FT THROUGH THE WEEKEND...WITH
SOME 4 FT SEAS DEVELOPING ACROSS THE OUTER WATERS LATE MON AND MON
NIGHT.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 2 PM THURSDAY TO 5 AM EDT FRIDAY
FOR AMZ250-252.
&&
$$
NEAR TERM...JDW
SHORT TERM...SRP
LONG TERM...RJD
AVIATION...DL/JDW
AREA FORECAST DISCUSSION
NWS RALEIGH NC
250 PM EDT WED JUN 12 2013
.SYNOPSIS...
A LOW PRESSURE SYSTEM AND ASSOCIATED COLD FRONT WILL PROGRESS FROM
THE CENTRAL PLAINS INTO THE OHIO VALLEY TONIGHT...THEN MOVE ACROSS
THE MID ATLANTIC AND CAROLINAS ON THURSDAY AFTERNOON AND EVENING. A
COOLER AND DRIER AIR MASS WILL BUILD INTO THE REGION BEHIND THE COLD
FRONT FOR FRIDAY AND SATURDAY.
&&
.NEAR TERM /THIS AFTERNOON AND TONIGHT/...
AS OF 250 PM WEDNESDAY...
LATEST SFC ANALYSIS SHOWS COLD FRONT EXTENDED FROM NEAR KORD EAST
AND SOUTHEAST INTO THE NORTHERN CHESAPEAKE BAY. A BROAD SFC TROUGH
HAS SET UP OVER THE WESTERN CAROLINAS WITH A LIGHT SOUTHWESTERLY
SURFACE FLOW. SURFACE DEWPOINTS RANGE IN THE UPPER 60S IN THE
WESTERN PIEDMONT TO MID 60S FURTHER EAST WITH TEMPERATURES IN THE
UPPER 80S TO NEAR 90. THE AIR MASS IN THE WESTERN PIEDMONT IS
STRONGLY UNSTABLE WITH MLCAPE VALUES EXCEEDING 3000 J/KG WITH A
MODERATELY UNSTABLE AIRMASS FURTHER EAST.
WE HAVE BEEN CONCERNED ABOUT THE POTENTIAL FOR CONVECTION TO DEVELOP
IN OR UPSTREAM OF THIS AIRMASS AND THEN MOVE ACROSS CENTRAL NC. A
DISTURBANCE IN THE NW FLOW ALOFT MOVED THROUGH CENTRAL NC LATE THIS
MORNING WITH SOME BRIEF RIDGING ALOFT THIS AFTERNOON BEFORE ANOTHER
DISTURBANCE MOVES ACROSS SOUTHEAST VA AND NORTHEAST NC LATER THIS
EVENING. THE NAM AND TO A LESSER EXTENT RAP BUFR SOUNDINGS HAVE
NOTED A LOW LEVEL CAP THAT SHOULD LIMIT CONVECTIVE COVERAGE.
CONVECTION ALLOWING MODELS HAVE STRUGGLED WITH THE POTENTIAL FOR
CONVECTION TODAY GIVEN THE WEAKER FORCING AND MORE SUBTLE FEATURES.
THEY CURRENTLY PROVIDE A VARIETY OF SOLUTIONS THIS EVENING BUT THEIR
TREND IS FOR LESS COVERAGE WITH THE GREATEST CHANCE IN THE WESTERN
PIEDMONT THIS EVENING. WILL INCLUDE SLIGHT CHANCE POPS IN THE WEST
THIS EVENING BUT KEEP THE REST OF THE AREA DRY WITH FAIR SKIES.
EXPECT LOWS OVERNIGHT IN THE 68 TO 73 RANGE. -BLAES
&&
.SHORT TERM /THURSDAY AND THURSDAY NIGHT/...
AS OF 300 AM WEDNESDAY...
...SEVERE WEATHER EXPECTED THURSDAY AFTERNOON AND EVENING...
THURSDAY AND THURSDAY NIGHT:
AN UNSEASONABLY AMPLIFIED PATTERN WILL PERSIST ON THU...
CHARACTERIZED BY A STRONG UPPER LEVEL RIDGE OVER THE CENTRAL CONUS
AND NW FLOW ALOFT DOWNSTREAM ACROSS THE TN/OH VALLEY AND
MID-ATLANTIC. ROBUST SHORTWAVE ENERGY (AND AN ATTENDANT SFC LOW) IN
THE OH VALLEY THU MORNING WILL TRACK EAST ACROSS THE MID-ATLANTIC
THU AFTERNOON AND EVENING. MODERATE INSTABILITY (1500-2500 J/KG
MLCAPE) IS EXPECTED ACROSS CENTRAL NC...IN ASSOCIATION WITH STEEP
(6.5-7.5 C/KM) MID-LEVEL LAPSE RATES AND SEASONABLE BOUNDARY LAYER
MOISTURE. STRENGTHENING WESTERLY FLOW ALOFT IN ADVANCE OF THE
SHORTWAVE WILL RESULT IN 0-6 KM SHEAR ON THE ORDER OF 25-40 KT
(STRONGEST NORTH)...SUFFICIENT FOR ORGANIZED CONVECTION...ESPECIALLY
IN THE PRESENCE OF MODERATE INSTABILITY AND STEEP MID-LEVEL LAPSE
RATES.
SOME UNCERTAINTY PERSISTS WITH REGARD TO THE SPECIFICS OF THIS
SYSTEM GIVEN SMALL VARIANCES IN TIMING AND ONGOING CONVECTION /MCS
ACTIVITY/ EXPECTED TO TRACK INTO THE APPALACHIANS THU MORNING. GIVEN
EXCELLENT SYNOPTIC FORCING...MODERATE DESTABILIZATION AND FAVORABLE
DEEP-LAYER SHEAR...A SIGNIFICANT SEVERE WEATHER EPISODE IS EXPECTED
ACROSS THE REGION THU AFTERNOON AND EVENING. FROM A PATTERN
RECOGNITION STANDPOINT...THE EXPECTED ENVIRONMENT IN CENTRAL NC
WOULD PRIMARILY SUPPORT AN ENHANCED THREAT OF DAMAGING WINDS GIVEN
UNIDIRECTIONAL DEEP-LAYER SHEAR...SPEEDY MID-LEVEL FLOW AND STRONG
EVAP COOLING POTENTIAL ASSOC/W THE MODIFIED EML IN PLACE AND
INVERTED-V PROFILES IN THE BOUNDARY LAYER. W/REGARD TO CONVECTIVE
MODE...EXPECT A RELATIVELY NARROW WINDOW FOR ANY DISCRETE CONVECTION
PRIOR TO RAPID UPSCALE GROWTH INTO AN MCS GIVEN HIGH DCAPE /STRONG
COLD POOLS/ AND MODERATE INSTABILITY. THE LATEST GUIDANCE SUGGESTS
THAT THE TORNADO THREAT WOULD LIKELY REMAIN WELL TO THE NORTH (I.E.
NORTHERN VA/MD/PA/NJ) AND OTHER PORTIONS OF THE MID-ATLANTIC
COAST...IN CLOSER VICINITY TO THE SFC LOW TRACK AND WARM FRONT AND
BETTER LOW-LEVEL DIRECTIONAL SHEAR. WITH EXPECTED MCS ACTIVITY AND
OUTFLOW PROGRESSING INTO THE MOUNTAINS THU MORNING AND A POTENTIAL
FOR HINDERED DESTABILIZATION MID/LATE THU MORNING INTO EARLY THU
AFTERNOON IN THE FAR W/NW PIEDMONT...HAVE DECREASED PRECIP CHANCES
TO 40% IN THAT AREA...WITH PRECIP CHANCES AT 50% IN VICINITY OF THE
HWY 1 CORRIDOR AND 60-70% EAST OF INTERSTATE 95. EXPECT THE BEST
SEVERE THREAT EAST OF HWY 1 AT THIS TIME. HIGHS LOWER TO MID
90S...WARMEST EAST...THOUGH CONFIDENCE IS LOWER THAN NORMAL GIVEN
UNCERTAINTY W/REGARD TO MCS ACTIVITY/CLOUD COVER THAT MAY PROGRESS
INTO WESTERN PORTIONS OF THE STATE IN THE MORNING. EXPECT LOWS THU
NIGHT IN THE MID TO UPPER 60S IN THE WAKE OF A COLD FRONTAL PASSAGE
AS THE SHORTWAVE AND ATTENDANT SFC LOW TRACK OFFSHORE THE
MID-ATLANTIC. -VINCENT
&&
.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
AS OF 240 PM WEDNESDAY...
CONDITIONS WILL DRY OUT AND COOL DOWN BEHIND THE DEPARTING SYSTEM
FOR THE END OF THE WORK WEEK AND EARLY WEEKEND. THE STRONG MID/UPPER
LEVEL TROUGH WILL BE CROSSING THE AREA DURING THE DAY ON FRIDAY AND
VERY WELL COULD PRODUCE A COUPLE OF SHOWERS OR SOME SPRINKLES.
HOWEVER...THE DEEP MOISTURE WILL HAVE MOVED OFFSHORE...SO AM NOT
EXPECTING ENOUGH COVERAGE TO PUT ANY MENTION IN THE FORECAST. IF
ANYTHING DOES DEVELOP...IT SHOULD BE ACROSS THE EASTERN THIRD OF THE
FORECAST AREA WHERE SOME RESIDUAL MOISTURE (PWAT VALUES NEAR AN
INCH) MAY RESIDE.
THEN...SURFACE HIGH PRESSURE AND RISING HEIGHTS ALOFT (ALTHOUGH THE
CORE OF THE MID/UPPER HIGH WILL REMAIN WEST OF OF THE REGION BEFORE
FLATTENING OUT BY THE LATTER HALF OF THE WEEKEND) WILL LEAD TO MORE
SUNSHINE AND MOSTLY DRY CONDITIONS THROUGH MUCH OF THE WEEKEND.
TEMPS SHOULD STAY BELOW NORMAL (HIGHS IN THE LOW/MID 80S...OVERNIGHT
LOWS IN THE LOW 60S...WITH EVEN SOME UPPER 50S POSSIBLE) FRIDAY AND
SATURDAY...BEFORE MODIFYING ON SUNDAY AS THE SURFACE HIGH SHIFTS
OFFSHORE. THE NEXT SYSTEM LOOKS TO APPROACH THE REGION EARLY NEXT
WEEK...BUT THERE ARE STILL SOME TIMING/STRENGTH ISSUES BETWEEN THE
MODELS. AT THIS TIME...IT APPEARS A FRONT WILL MOVE THROUGH THE AREA
SOMETIME ON TUESDAY...WHICH IS WHEN THE BEST CHANCE OF RAIN WILL BE
FOCUSED. HOWEVER...INCREASING SOUTHWESTERLY FLOW WILL DRIVE OUR
MOISTURE BACK UP AND THEREFORE WILL HAVE SLIGHT CHANCE POPS FOR
MONDAY. TEMPS WILL BE NEAR NORMAL FOR THE BEGINNING ON NEXT WEEK.
&&
.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
AS OF 140 PM WEDNESDAY...
VFR CONDITIONS ARE EXPECTED TO PREVAIL THROUGH THE CURRENT TAF
PERIOD. THERE COULD BE AN ISOLATED SHOWER OR THUNDERSTORM THAT
DEVELOPS LATER THIS AFTERNOON...MOST LIKELY ACROSS THE WEST...BUT
CHANCES ARE TOO SMALL TO INCLUDE ANY MENTION IN THE TAFS.
OTHERWISE...SOUTHWESTERLY WINDS WILL INCREASE THURSDAY MORNING...
WITH GUSTS AROUND 25 KNOTS POSSIBLE. IT STILL APPEARS THAT THE
MAJORITY OF THE PRECIP WILL HOLD OFF UNTIL AFTER 18Z THURSDAY.
OUTLOOK...ADVERSE AVIATION CONDITIONS IN THE FORM OF SCATTERED TO
WIDESPREAD SHOWERS AND THUNDERSTORMS ARE EXPECTED DURING THE DAY
THURSDAY...LIKELY BEGINNING SHORTLY AFTER 18Z. ANY THUNDERSTORMS
THAT DEVELOP WILL BE CAPABLE OF PRODUCING DAMAGING SURFACE WIND
GUSTS IN EXCESS OF 50 KNOTS. AT THIS TIME...THE BEST CHANCE FOR
AFTERNOON CONVECTION AND SEVERE WEATHER WILL BE AT THE RDU/FAY/RWI
TERMINALS. GUSTY SOUTHWESTERLY WINDS (SEE ABOVE PARAGRAPH) WILL
SHIFT TO THE NORTHWEST IN THE WAKE OF A COLD FRONTAL PASSAGE
THURSDAY EVENING/NIGHT. EXPECT DRY/VFR CONDITIONS TO PREVAIL IN THE
WAKE OF THE FRONT FRIDAY THROUGH THE WEEKEND...WITH THE NEXT CHANCE
OF PRECIP RETURNING TO THE AREA EARLY NEXT WEEK.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...BLAES
NEAR TERM...BLAES
SHORT TERM...VINCENT
LONG TERM...KRR
AVIATION...KRR/VINCENT
AREA FORECAST DISCUSSION
NWS RALEIGH NC
243 PM EDT WED JUN 12 2013
.SYNOPSIS...
A DEEPENING LOW PRESSURE SYSTEM AND ASSOCIATED COLD FRONT WILL
PROGRESS FROM THE CENTRAL PLAINS INTO THE OHIO VALLEY TONIGHT...THEN
TRACK EAST THROUGH THE MID ATLANTIC AND CAROLINAS ON THURSDAY. DRY
HIGH PRESSURE WILL BUILD INTO THE REGION IN THE WAKE OF THE COLD
FRONT THURSDAY NIGHT AND FRIDAY.
&&
.NEAR TERM /TODAY AND TONIGHT/...
AS OF 1100 AM WEDNESDAY...
AN UPPER LEVEL RIDGE CENTERED OVER THE SOUTHERN PLAINS WILL
STRENGTHEN SOMEWHAT TODAY WITH MINOR HEIGHT RISES ACROSS THE MID
ATLANTIC. SMALL AMPLITUDE DISTURBANCES IN NW FLOW ALOFT ARE
EXPECTED TO TRACK SOUTHEAST INTO THE CAROLINAS THIS AFTERNOON
THROUGH TONIGHT WHILE A MUCH MORE POTENT SHORTWAVE CENTERED ATOP THE
RIDGE IN THE NORTHERN PLAINS THIS MORNING WILL TRACK INTO THE TN/OH
VALLEY TONIGHT. A WEAK SURFACE TROUGH ACROSS CENTRAL NC WILL PERSIST
ACROSS WESTERN/CENTRAL NC WITH A LIGHT SW SURFACE WIND BECOMING MORE
WESTERLY THIS AFTERNOON.
WE HAVE BEEN MONITORING A REGION OF ISOLATED CONVECTION IN THE
CENTRAL APPALACHIANS THAT DEVELOPED OVERNIGHT. THE FACT THIS
DEVELOPED DURING AN ATYPICAL TIME OF DAY SUGGEST THAT SOME MESOSCALE
FORCING IS LIKELY DRIVING THIS AND IT APPEARS TO BE DEVELOPING IN A
REGION OF WARM ADVECTION AND ENHANCED MID LEVEL FLOW. CONVECTION
ALLOWING MODELS PROVIDE A VARIETY OF SOLUTIONS WITH THIS CONVECTION:
THE 00 UTC ARW/NMM HI RES WINDOWS SUGGEST SOME OF THE CONVECTION
WILL PERSIST AND GROW INTO A CLUSTER OF CONVECTION AROUND MIDDAY AND
SWEEP SOUTHEAST ACROSS THE PIEDMONT WHILE THE HRRR SUGGESTS THAT
ONGOING CONVECTION WILL WEAKEN WITH LITTLE ADDITIONAL REDEVELOPMENT
LIKELY. WITH RECENT RADAR TRENDS SUGGESTING A DECREASE IN
INTENSITY/COVERAGE OF THE CONVECTION AND THE PERSISTENCE OF A MID
LEVEL CAPPING INVERSION...HAVE OPTED TO REMOVE SLIGHT CHANCE POPS IN
THE EAST THIS AFTERNOON AND HIGHLIGHT THE FAR WEST DURING THE EARLY
TO MID AFTERNOON PERIOD FOR SLIGHT CHC POPS...ESPECIALLY ALONG THE
YADKIN RIVER.
CONVECTIVE DEBRIS CLOUDS ARE ALREADY SPREADING ACROSS THE WESTERN
PIEDMONT AND WILL SWEEP INTO THE EASTERN PIEDMONT AND SANDHILLS THIS
AFTERNOON. THE THICKER CLOUDS CLOSE TO THE YADKIN SHOULD BE
SUFFICIENT ENOUGH TO RETARD TEMPERATURES A DEGREE OR TWO. BUT WE
STILL EXPECT HIGHS TO RANGE IN THE 88 TO 95 RANGE TODAY. EXPECT LOWS
OVERNIGHT IN THE 69 TO 73 RANGE. -BLAES/VINCENT
&&
.SHORT TERM /THURSDAY AND THURSDAY NIGHT/...
AS OF 300 AM WEDNESDAY...
...SEVERE WEATHER EXPECTED THURSDAY AFTERNOON AND EVENING...
THURSDAY AND THURSDAY NIGHT:
AN UNSEASONABLY AMPLIFIED PATTERN WILL PERSIST ON THU...
CHARACTERIZED BY A STRONG UPPER LEVEL RIDGE OVER THE CENTRAL CONUS
AND NW FLOW ALOFT DOWNSTREAM ACROSS THE TN/OH VALLEY AND
MID-ATLANTIC. ROBUST SHORTWAVE ENERGY (AND AN ATTENDANT SFC LOW) IN
THE OH VALLEY THU MORNING WILL TRACK EAST ACROSS THE MID-ATLANTIC
THU AFTERNOON AND EVENING. MODERATE INSTABILITY (1500-2500 J/KG
MLCAPE) IS EXPECTED ACROSS CENTRAL NC...IN ASSOCIATION WITH STEEP
(6.5-7.5 C/KM) MID-LEVEL LAPSE RATES AND SEASONABLE BOUNDARY LAYER
MOISTURE. STRENGTHENING WESTERLY FLOW ALOFT IN ADVANCE OF THE
SHORTWAVE WILL RESULT IN 0-6 KM SHEAR ON THE ORDER OF 25-40 KT
(STRONGEST NORTH)...SUFFICIENT FOR ORGANIZED CONVECTION...ESPECIALLY
IN THE PRESENCE OF MODERATE INSTABILITY AND STEEP MID-LEVEL LAPSE
RATES.
SOME UNCERTAINTY PERSISTS WITH REGARD TO THE SPECIFICS OF THIS
SYSTEM GIVEN SMALL VARIANCES IN TIMING AND ONGOING CONVECTION /MCS
ACTIVITY/ EXPECTED TO TRACK INTO THE APPALACHIANS THU MORNING. GIVEN
EXCELLENT SYNOPTIC FORCING...MODERATE DESTABILIZATION AND FAVORABLE
DEEP-LAYER SHEAR...A SIGNIFICANT SEVERE WEATHER EPISODE IS EXPECTED
ACROSS THE REGION THU AFTERNOON AND EVENING. FROM A PATTERN
RECOGNITION STANDPOINT...THE EXPECTED ENVIRONMENT IN CENTRAL NC
WOULD PRIMARILY SUPPORT AN ENHANCED THREAT OF DAMAGING WINDS GIVEN
UNIDIRECTIONAL DEEP-LAYER SHEAR...SPEEDY MID-LEVEL FLOW AND STRONG
EVAP COOLING POTENTIAL ASSOC/W THE MODIFIED EML IN PLACE AND
INVERTED-V PROFILES IN THE BOUNDARY LAYER. W/REGARD TO CONVECTIVE
MODE...EXPECT A RELATIVELY NARROW WINDOW FOR ANY DISCRETE CONVECTION
PRIOR TO RAPID UPSCALE GROWTH INTO AN MCS GIVEN HIGH DCAPE /STRONG
COLD POOLS/ AND MODERATE INSTABILITY. THE LATEST GUIDANCE SUGGESTS
THAT THE TORNADO THREAT WOULD LIKELY REMAIN WELL TO THE NORTH (I.E.
NORTHERN VA/MD/PA/NJ) AND OTHER PORTIONS OF THE MID-ATLANTIC
COAST...IN CLOSER VICINITY TO THE SFC LOW TRACK AND WARM FRONT AND
BETTER LOW-LEVEL DIRECTIONAL SHEAR. WITH EXPECTED MCS ACTIVITY AND
OUTFLOW PROGRESSING INTO THE MOUNTAINS THU MORNING AND A POTENTIAL
FOR HINDERED DESTABILIZATION MID/LATE THU MORNING INTO EARLY THU
AFTERNOON IN THE FAR W/NW PIEDMONT...HAVE DECREASED PRECIP CHANCES
TO 40% IN THAT AREA...WITH PRECIP CHANCES AT 50% IN VICINITY OF THE
HWY 1 CORRIDOR AND 60-70% EAST OF INTERSTATE 95. EXPECT THE BEST
SEVERE THREAT EAST OF HWY 1 AT THIS TIME. HIGHS LOWER TO MID
90S...WARMEST EAST...THOUGH CONFIDENCE IS LOWER THAN NORMAL GIVEN
UNCERTAINTY W/REGARD TO MCS ACTIVITY/CLOUD COVER THAT MAY PROGRESS
INTO WESTERN PORTIONS OF THE STATE IN THE MORNING. EXPECT LOWS THU
NIGHT IN THE MID TO UPPER 60S IN THE WAKE OF A COLD FRONTAL PASSAGE
AS THE SHORTWAVE AND ATTENDANT SFC LOW TRACK OFFSHORE THE
MID-ATLANTIC. -VINCENT
&&
.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
AS OF 240 PM WEDNESDAY...
CONDITIONS WILL DRY OUT AND COOL DOWN BEHIND THE DEPARTING SYSTEM
FOR THE END OF THE WORK WEEK AND EARLY WEEKEND. THE STRONG MID/UPPER
LEVEL TROUGH WILL BE CROSSING THE AREA DURING THE DAY ON FRIDAY AND
VERY WELL COULD PRODUCE A COUPLE OF SHOWERS OR SOME SPRINKLES.
HOWEVER...THE DEEP MOISTURE WILL HAVE MOVED OFFSHORE...SO AM NOT
EXPECTING ENOUGH COVERAGE TO PUT ANY MENTION IN THE FORECAST. IF
ANYTHING DOES DEVELOP...IT SHOULD BE ACROSS THE EASTERN THIRD OF THE
FORECAST AREA WHERE SOME RESIDUAL MOISTURE (PWAT VALUES NEAR AN
INCH) MAY RESIDE.
THEN...SURFACE HIGH PRESSURE AND RISING HEIGHTS ALOFT (ALTHOUGH THE
CORE OF THE MID/UPPER HIGH WILL REMAIN WEST OF OF THE REGION BEFORE
FLATTENING OUT BY THE LATTER HALF OF THE WEEKEND) WILL LEAD TO MORE
SUNSHINE AND MOSTLY DRY CONDITIONS THROUGH MUCH OF THE WEEKEND.
TEMPS SHOULD STAY BELOW NORMAL (HIGHS IN THE LOW/MID 80S...OVERNIGHT
LOWS IN THE LOW 60S...WITH EVEN SOME UPPER 50S POSSIBLE) FRIDAY AND
SATURDAY...BEFORE MODIFYING ON SUNDAY AS THE SURFACE HIGH SHIFTS
OFFSHORE. THE NEXT SYSTEM LOOKS TO APPROACH THE REGION EARLY NEXT
WEEK...BUT THERE ARE STILL SOME TIMING/STRENGTH ISSUES BETWEEN THE
MODELS. AT THIS TIME...IT APPEARS A FRONT WILL MOVE THROUGH THE AREA
SOMETIME ON TUESDAY...WHICH IS WHEN THE BEST CHANCE OF RAIN WILL BE
FOCUSED. HOWEVER...INCREASING SOUTHWESTERLY FLOW WILL DRIVE OUR
MOISTURE BACK UP AND THEREFORE WILL HAVE SLIGHT CHANCE POPS FOR
MONDAY. TEMPS WILL BE NEAR NORMAL FOR THE BEGINNING ON NEXT WEEK.
&&
.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
AS OF 140 PM WEDNESDAY...
VFR CONDITIONS ARE EXPECTED TO PREVAIL THROUGH THE CURRENT TAF
PERIOD. THERE COULD BE AN ISOLATED SHOWER OR THUNDERSTORM THAT
DEVELOPS LATER THIS AFTERNOON...MOST LIKELY ACROSS THE WEST...BUT
CHANCES ARE TOO SMALL TO INCLUDE ANY MENTION IN THE TAFS.
OTHERWISE...SOUTHWESTERLY WINDS WILL INCREASE THURSDAY MORNING...
WITH GUSTS AROUND 25 KNOTS POSSIBLE. IT STILL APPEARS THAT THE
MAJORITY OF THE PRECIP WILL HOLD OFF UNTIL AFTER 18Z THURSDAY.
OUTLOOK...ADVERSE AVIATION CONDITIONS IN THE FORM OF SCATTERED TO
WIDESPREAD SHOWERS AND THUNDERSTORMS ARE EXPECTED DURING THE DAY
THURSDAY...LIKELY BEGINNING SHORTLY AFTER 18Z. ANY THUNDERSTORMS
THAT DEVELOP WILL BE CAPABLE OF PRODUCING DAMAGING SURFACE WIND
GUSTS IN EXCESS OF 50 KNOTS. AT THIS TIME...THE BEST CHANCE FOR
AFTERNOON CONVECTION AND SEVERE WEATHER WILL BE AT THE RDU/FAY/RWI
TERMINALS. GUSTY SOUTHWESTERLY WINDS (SEE ABOVE PARAGRAPH) WILL
SHIFT TO THE NORTHWEST IN THE WAKE OF A COLD FRONTAL PASSAGE
THURSDAY EVENING/NIGHT. EXPECT DRY/VFR CONDITIONS TO PREVAIL IN THE
WAKE OF THE FRONT FRIDAY THROUGH THE WEEKEND...WITH THE NEXT CHANCE
OF PRECIP RETURNING TO THE AREA EARLY NEXT WEEK.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...VINCENT
NEAR TERM...BLAES/VINCENT
SHORT TERM...VINCENT
LONG TERM...KRR
AVIATION...KRR/VINCENT
AREA FORECAST DISCUSSION
NWS RALEIGH NC
143 PM EDT WED JUN 12 2013
.SYNOPSIS...
A DEEPENING LOW PRESSURE SYSTEM AND ASSOCIATED COLD FRONT WILL
PROGRESS FROM THE CENTRAL PLAINS INTO THE OHIO VALLEY TONIGHT...THEN
TRACK EAST THROUGH THE MID ATLANTIC AND CAROLINAS ON THURSDAY. DRY
HIGH PRESSURE WILL BUILD INTO THE REGION IN THE WAKE OF THE COLD
FRONT THURSDAY NIGHT AND FRIDAY.
&&
.NEAR TERM /TODAY AND TONIGHT/...
AS OF 1100 AM WEDNESDAY...
AN UPPER LEVEL RIDGE CENTERED OVER THE SOUTHERN PLAINS WILL
STRENGTHEN SOMEWHAT TODAY WITH MINOR HEIGHT RISES ACROSS THE MID
ATLANTIC. SMALL AMPLITUDE DISTURBANCES IN NW FLOW ALOFT ARE
EXPECTED TO TRACK SOUTHEAST INTO THE CAROLINAS THIS AFTERNOON
THROUGH TONIGHT WHILE A MUCH MORE POTENT SHORTWAVE CENTERED ATOP THE
RIDGE IN THE NORTHERN PLAINS THIS MORNING WILL TRACK INTO THE TN/OH
VALLEY TONIGHT. A WEAK SURFACE TROUGH ACROSS CENTRAL NC WILL PERSIST
ACROSS WESTERN/CENTRAL NC WITH A LIGHT SW SURFACE WIND BECOMING MORE
WESTERLY THIS AFTERNOON.
WE HAVE BEEN MONITORING A REGION OF ISOLATED CONVECTION IN THE
CENTRAL APPALACHIANS THAT DEVELOPED OVERNIGHT. THE FACT THIS
DEVELOPED DURING AN ATYPICAL TIME OF DAY SUGGEST THAT SOME MESOSCALE
FORCING IS LIKELY DRIVING THIS AND IT APPEARS TO BE DEVELOPING IN A
REGION OF WARM ADVECTION AND ENHANCED MID LEVEL FLOW. CONVECTION
ALLOWING MODELS PROVIDE A VARIETY OF SOLUTIONS WITH THIS CONVECTION:
THE 00 UTC ARW/NMM HI RES WINDOWS SUGGEST SOME OF THE CONVECTION
WILL PERSIST AND GROW INTO A CLUSTER OF CONVECTION AROUND MIDDAY AND
SWEEP SOUTHEAST ACROSS THE PIEDMONT WHILE THE HRRR SUGGESTS THAT
ONGOING CONVECTION WILL WEAKEN WITH LITTLE ADDITIONAL REDEVELOPMENT
LIKELY. WITH RECENT RADAR TRENDS SUGGESTING A DECREASE IN
INTENSITY/COVERAGE OF THE CONVECTION AND THE PERSISTENCE OF A MID
LEVEL CAPPING INVERSION...HAVE OPTED TO REMOVE SLIGHT CHANCE POPS IN
THE EAST THIS AFTERNOON AND HIGHLIGHT THE FAR WEST DURING THE EARLY
TO MID AFTERNOON PERIOD FOR SLIGHT CHC POPS...ESPECIALLY ALONG THE
YADKIN RIVER.
CONVECTIVE DEBRIS CLOUDS ARE ALREADY SPREADING ACROSS THE WESTERN
PIEDMONT AND WILL SWEEP INTO THE EASTERN PIEDMONT AND SANDHILLS THIS
AFTERNOON. THE THICKER CLOUDS CLOSE TO THE YADKIN SHOULD BE
SUFFICIENT ENOUGH TO RETARD TEMPERATURES A DEGREE OR TWO. BUT WE
STILL EXPECT HIGHS TO RANGE IN THE 88 TO 95 RANGE TODAY. EXPECT LOWS
OVERNIGHT IN THE 69 TO 73 RANGE. -BLAES/VINCENT
&&
.SHORT TERM /THURSDAY AND THURSDAY NIGHT/...
AS OF 300 AM WEDNESDAY...
...SEVERE WEATHER EXPECTED THURSDAY AFTERNOON AND EVENING...
THURSDAY AND THURSDAY NIGHT:
AN UNSEASONABLY AMPLIFIED PATTERN WILL PERSIST ON THU...
CHARACTERIZED BY A STRONG UPPER LEVEL RIDGE OVER THE CENTRAL CONUS
AND NW FLOW ALOFT DOWNSTREAM ACROSS THE TN/OH VALLEY AND
MID-ATLANTIC. ROBUST SHORTWAVE ENERGY (AND AN ATTENDANT SFC LOW) IN
THE OH VALLEY THU MORNING WILL TRACK EAST ACROSS THE MID-ATLANTIC
THU AFTERNOON AND EVENING. MODERATE INSTABILITY (1500-2500 J/KG
MLCAPE) IS EXPECTED ACROSS CENTRAL NC...IN ASSOCIATION WITH STEEP
(6.5-7.5 C/KM) MID-LEVEL LAPSE RATES AND SEASONABLE BOUNDARY LAYER
MOISTURE. STRENGTHENING WESTERLY FLOW ALOFT IN ADVANCE OF THE
SHORTWAVE WILL RESULT IN 0-6 KM SHEAR ON THE ORDER OF 25-40 KT
(STRONGEST NORTH)...SUFFICIENT FOR ORGANIZED CONVECTION...ESPECIALLY
IN THE PRESENCE OF MODERATE INSTABILITY AND STEEP MID-LEVEL LAPSE
RATES.
SOME UNCERTAINTY PERSISTS WITH REGARD TO THE SPECIFICS OF THIS
SYSTEM GIVEN SMALL VARIANCES IN TIMING AND ONGOING CONVECTION /MCS
ACTIVITY/ EXPECTED TO TRACK INTO THE APPALACHIANS THU MORNING. GIVEN
EXCELLENT SYNOPTIC FORCING...MODERATE DESTABILIZATION AND FAVORABLE
DEEP-LAYER SHEAR...A SIGNIFICANT SEVERE WEATHER EPISODE IS EXPECTED
ACROSS THE REGION THU AFTERNOON AND EVENING. FROM A PATTERN
RECOGNITION STANDPOINT...THE EXPECTED ENVIRONMENT IN CENTRAL NC
WOULD PRIMARILY SUPPORT AN ENHANCED THREAT OF DAMAGING WINDS GIVEN
UNIDIRECTIONAL DEEP-LAYER SHEAR...SPEEDY MID-LEVEL FLOW AND STRONG
EVAP COOLING POTENTIAL ASSOC/W THE MODIFIED EML IN PLACE AND
INVERTED-V PROFILES IN THE BOUNDARY LAYER. W/REGARD TO CONVECTIVE
MODE...EXPECT A RELATIVELY NARROW WINDOW FOR ANY DISCRETE CONVECTION
PRIOR TO RAPID UPSCALE GROWTH INTO AN MCS GIVEN HIGH DCAPE /STRONG
COLD POOLS/ AND MODERATE INSTABILITY. THE LATEST GUIDANCE SUGGESTS
THAT THE TORNADO THREAT WOULD LIKELY REMAIN WELL TO THE NORTH (I.E.
NORTHERN VA/MD/PA/NJ) AND OTHER PORTIONS OF THE MID-ATLANTIC
COAST...IN CLOSER VICINITY TO THE SFC LOW TRACK AND WARM FRONT AND
BETTER LOW-LEVEL DIRECTIONAL SHEAR. WITH EXPECTED MCS ACTIVITY AND
OUTFLOW PROGRESSING INTO THE MOUNTAINS THU MORNING AND A POTENTIAL
FOR HINDERED DESTABILIZATION MID/LATE THU MORNING INTO EARLY THU
AFTERNOON IN THE FAR W/NW PIEDMONT...HAVE DECREASED PRECIP CHANCES
TO 40% IN THAT AREA...WITH PRECIP CHANCES AT 50% IN VICINITY OF THE
HWY 1 CORRIDOR AND 60-70% EAST OF INTERSTATE 95. EXPECT THE BEST
SEVERE THREAT EAST OF HWY 1 AT THIS TIME. HIGHS LOWER TO MID
90S...WARMEST EAST...THOUGH CONFIDENCE IS LOWER THAN NORMAL GIVEN
UNCERTAINTY W/REGARD TO MCS ACTIVITY/CLOUD COVER THAT MAY PROGRESS
INTO WESTERN PORTIONS OF THE STATE IN THE MORNING. EXPECT LOWS THU
NIGHT IN THE MID TO UPPER 60S IN THE WAKE OF A COLD FRONTAL PASSAGE
AS THE SHORTWAVE AND ATTENDANT SFC LOW TRACK OFFSHORE THE
MID-ATLANTIC. -VINCENT
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
AS OF 300 AM WEDNESDAY...
FRIDAY AND FRIDAY NIGHT...THE LONGWAVE TROUGH MOVES EAST
FRIDAY...WITH AMPLE NVA IN THE MID-LEVELS TAKING PLACE FRIDAY NIGHT.
THE MEAN AIR MASS IS DRY...WITH A SLIGHT INCREASE IN OVERALL
MOISTURE TOWARD THE NORTHEAST PART OF THE STATE...INCLUDING THE
NORTHERN COASTAL PLAIN...CLOSER TO THE DEPARTING MID-LEVEL LOW. THE
GFS FORECASTS LINGERING...HIGHER PRECIPITABLE WATER VALUES NEAR AN
INCH TOWARD KIXA FRIDAY AFTERNOON...ALTHOUGH GFS BUFR SOUNDINGS AS
WELL AS NAM BUFR SOUNDINGS ARE STABLE AND CAPPED AROUND 700MB.
INTERESTINGLY BUT NOT TERRIBLY SURPRISING GIVEN THE STRENGTH OF THE
DEPARTING UPPER LOW...THE NAM AND GFS PRODUCE MEAGER...JUST
NOTICEABLE QPF MAINLY JUST EAST OF CENTRAL NORTH CAROLINA OVER THE
NORTHEAST PART OF THE STATE DURING FRIDAY AFTERNOON. SIMILAR
SCENARIOS HAVE OCCURRED IN THE RECENT PAST...BEHIND STRONG MID-LEVEL
SYSTEMS WHERE ENOUGH MOISTURE LINGERS TO RESULT IN ISOLATED SHOWERS
OR SPRINKLES SKIRTING OR MOVING INTO CENTRAL NORTH CAROLINA FROM THE
NORTHEAST. ON FRIDAY...WHILE A SPRINKLE MAY OCCUR LATE IN THE DAY
TOWARD KIXA...THE GFS FORECAST COMBINATION OF BEST 850MB AND 700MB
MOISTURE RESIDES JUST EAST OF CENTRAL NORTH CAROLINA BETWEEN 18Z
FRIDAY AND 00Z SATURDAY. AS A RESULT...WILL KEEP THIS FORECAST
DRY...SHOWING A RELATIVELY HIGHER AMOUNT OF CLOUDS IN THE AREA
DURING THE AFTERNOON THROUGH THE EVENING MAINLY FROM WILSON NORTH.
1000-850MB THICKNESSES AND BIAS CORRECTED TEMPERATURE GUIDANCE ALL
FAVOR HIGHS NEAR THE COOLER MET GUIDANCE FOR FRIDAY...AND BUFR
SOUNDINGS SHOW THERE MAY BE ENOUGH HIGH-BASED CU/SC FOR HIGHS TO BE
TEMPERED SOMEWHAT FROM THE WARMER MAV VALUES. OVERNIGHT LOWS 57 TO
62. EXPECT A FEW WIND GUSTS IN THE UPPER TEENS TO POSSIBLY LOWER 20S
KNOTS FRIDAY WITH INITIAL MIXING IN THE TIGHT GRADIENT BEHIND THE
DEPARTING LOW.
FOR THE PERIOD SATURDAY THROUGH TUESDAY...THE FORECAST FOR SATURDAY
REMAINS DRY AS A STABLE AND DRY AIR MASS UNDER HIGH PRESSURE IS
ANTICIPATED. AS THE WEEKEND ENDS AND WE APPROACH THE BEGINNING OF
THE NEXT WORK WEEK...GUIDANCE IS CONSISTENT IN PUSHING MODESTLY
STRONG MID-LEVEL SHORTWAVES ATOP THE RIDGE TO OUR WEST...EVENTUALLY
FLATTENING THAT UPPER RIDGE. THE CENTER OF SURFACE HIGH PRESSURE
MOVES OFF TO THE EAST OF CENTRAL NORTH CAROLINA BY SUNDAY
AFTERNOON...BRINGING MORE MOISTURE INTO CENTRAL NORTH CAROLINA.
BASED ON THE CONSENSUS OF THE LATEST GFS AND THE 12Z ECMWF...THE
APPROACH OF THE NEXT SURFACE FRONT WILL BE AT LEAST LATE TUESDAY...
WITH THE TYPICAL PIEDMONT TROUGH IN PLACE FOR SUNDAY INTO MONDAY.
WHILE THERE IS A NOTICEABLE INCREASE IN 850MB THETA-E AIR SUNDAY AS
PRECIPITABLE WATER VALUES RISE FROM UNDER AN INCH SATURDAY TO CLOSE
TO 1.5 INCHES ON THE GFS...AND THERE IS A SLIGHT STEEPENING OF THE
MID-LEVEL LAPSE RATES...GFS BUFR SOUNDINGS ARE STILL CAPPED TO DEEP
CONVECTION SUNDAY AFTERNOON. THERE IS A LITTLE CONCERN ABOUT
UPSTREAM DEVELOPMENT MOVING INTO THE REGION...BUT THE GFS THICKNESS
PROFILE WOULD SUGGEST ANY SUCH DEVELOPMENT WOULD TEND TO TRACK WELL
NORTH AND NORTHEAST OF THE AREA. IF ANYTHING DEVELOPS AT ALL
SUNDAY...IT IS CURRENTLY EXPECTED TO BE VERY ISOLATED. AS HEIGHTS
ALOFT CONTINUE TO FALL...AND LAPSE RATES AT LEAST ON THE GFS STEEPEN
EVER SO SLIGHTLY MONDAY COMPARED TO SUNDAY AS MOISTURE CONTINUES TO
INCREASE...ISOLATED TO WIDELY SCATTERED THUNDERSTORMS ARE POSSIBLE.
THE GFS BUFR SOUNDINGS ARE STILL WEAKLY CAPPED MONDAY AROUND 750MB...
AND THE COARSE 12Z ECMWF SOUNDINGS ACTUALLY ARE MORE STABLE MONDAY
THAN SUNDAY...SO WILL KEEP CHANCES FOR PRECIPITATION SLIGHT AT THIS
TIME...AND LOWEST IN THAT RANGE OVER THE SANDHILLS AND SOUTHERN
COASTAL PLAIN. BY TUESDAY...WITH THE SLOW APPROACH OF THE FRONT...
AND A CONTINUED INCREASE IN MOISTURE AND COOLING ALOFT...AT LEAST
SCATTERED SHOWERS AND THUNDERSTORMS ARE EXPECTED. OVERNIGHT LOWS
WILL GRADUALLY RISE FROM THE LOWER TO MID 60S SATURDAY NIGHT TO 69
TO 74 BY MONDAY NIGHT. AFTER HIGHS SATURDAY CLOSE TO 1000-850MB
THICKNESSES IN THE LOWER TO MID 80S...FORECAST HIGHS WILL BE IN THE
MID 80S TO AROUND 90...WARMEST MONDAY WITH THIS FORECAST. ONE
POSSIBLE ALTERNATIVE IS THAT SUNDAY ACTUALLY ENDS UP WARMER THAN
MONDAY WHEN THE AIR IS A LITTLE DRIER AS THE SOUTHWEST SURFACE
FLOW INITIALLY BECOMES MORE ENTRENCHED. FOR THAT DAY...LEANED ON THE
HIGH SIDE OF THE AVAILABLE GUIDANCE SUITE. -DJF
&&
.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
AS OF 140 PM WEDNESDAY...
VFR CONDITIONS ARE EXPECTED TO PREVAIL THROUGH THE CURRENT TAF
PERIOD. THERE COULD BE AN ISOLATED SHOWER OR THUNDERSTORM THAT
DEVELOPS LATER THIS AFTERNOON...MOST LIKELY ACROSS THE WEST...BUT
CHANCES ARE TOO SMALL TO INCLUDE ANY MENTION IN THE TAFS.
OTHERWISE...SOUTHWESTERLY WINDS WILL INCREASE THURSDAY MORNING...
WITH GUSTS AROUND 25 KNOTS POSSIBLE. IT STILL APPEARS THAT THE
MAJORITY OF THE PRECIP WILL HOLD OFF UNTIL AFTER 18Z THURSDAY.
OUTLOOK...ADVERSE AVIATION CONDITIONS IN THE FORM OF SCATTERED TO
WIDESPREAD SHOWERS AND THUNDERSTORMS ARE EXPECTED DURING THE DAY
THURSDAY...LIKELY BEGINNING SHORTLY AFTER 18Z. ANY THUNDERSTORMS
THAT DEVELOP WILL BE CAPABLE OF PRODUCING DAMAGING SURFACE WIND
GUSTS IN EXCESS OF 50 KNOTS. AT THIS TIME...THE BEST CHANCE FOR
AFTERNOON CONVECTION AND SEVERE WEATHER WILL BE AT THE RDU/FAY/RWI
TERMINALS. GUSTY SOUTHWESTERLY WINDS (SEE ABOVE PARAGRAPH) WILL
SHIFT TO THE NORTHWEST IN THE WAKE OF A COLD FRONTAL PASSAGE
THURSDAY EVENING/NIGHT. EXPECT DRY/VFR CONDITIONS TO PREVAIL IN THE
WAKE OF THE FRONT FRIDAY THROUGH THE WEEKEND...WITH THE NEXT CHANCE
OF PRECIP RETURNING TO THE AREA EARLY NEXT WEEK.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...VINCENT
NEAR TERM...BLAES/VINCENT
SHORT TERM...VINCENT
LONG TERM...DJF
AVIATION...KRR/VINCENT
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
122 PM EDT WED JUN 12 2013
.SYNOPSIS...
HOT TEMPERATURES ARE EXPECTED TODAY AND THURSDAY AS AN UPPER RIDGE
MOVES ACROSS THE REGION. A FEW THUNDERSTORMS MAY DEVELOP INLAND
LATE IN THE AFTERNOON. A RELATIVELY STRONG COLD FRONT WILL MOVE
ACROSS THE AREA THURSDAY NIGHT WITH A GOOD CHANCE OF SHOWERS AND
THUNDERSTORMS. DRY WEATHER IS EXPECTED INTO THE WEEKEND. A COLD
FRONT WILL REACH THE CAROLINAS EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1100 AM WEDNESDAY...HOT AND HUMID DAY ON TAP FOR THE AREA AS
SUMMER MAKES ITS FIRST STRONG FORAY INTO THE CAROLINAS. WV IMAGERY
THIS MORNING PAINTS THE PICTURE WITH LARGE SURFACE HIGH AND MID
LEVEL RIDGING ELONGATED WEST-TO-EAST ACROSS THE SOUTHERN TIER AND
OUT INTO THE ATLANTIC OCEAN. THIS IS A MODIFIED "RING OF FIRE"
SETUP...AND STRONG CONVECTION IS ANTICIPATED ACROSS THE OH VLY INTO
THE MID-ATLANTIC TODAY. THE BIG QUESTIONS FOR TODAY WILL BE: 1) HOW
HOT WILL IT GET AND 2) WILL THERE BE CONVECTION THIS EVENING.
AS FAR AS TEMPERATURES GO...AM EXPECTING THE HOTTEST DAY SINCE
SEPTEMBER 1, 2012. 12Z SOUNDING AT KCHS SHOWED 850MB TEMPS OF
20C...WHILE KMHX HAD 15C. THIS SHOWS THE LEVEL OF WARMTH POSSIBLE
TODAY...AS MID-LEVEL THERMAL RIDGE WILL BULGE NORTHWARD TODAY...AND
NAM BUFR SOUNDINGS SHOW 3-4C OF WARMING AT 850MB THROUGH TONIGHT.
THESE VERY WARM TEMPS COMBINED WITH AMPLE SOLAR INSOLATION AND SOME
DOWNSLOPE WARMING THANKS TO NW FLOW ABOVE 900MB...WILL ALLOW TEMPS
TO SOAR WELL INTO THE 90S TODAY. HAVE SIDED WITH THE HIGHER MAV
NUMBERS...WHICH SUGGESTS TEMPS RISING TO 92-97 TODAY...WITH UPPER
80S EVEN AT THE IMMEDIATE BEACHES. THESE TEMPS COMBINED WITH
DEWPOINTS IN THE UPPER 60S...LOW 70S AT THE COAST...WILL DRIVE HEAT
INDICIES TO AROUND 100 DEGREES...AND A HEAT RELATED SPS REMAINS IN
EFFECT FOR TODAY.
FOR CONVECTION...THE SITUATION IS QUITE TRICKY. HIGH-RES GUIDANCE IS
SHOWING MANY DIFFERENT SOLUTIONS...BUT THERE ARE REALLY TWO CAMPS.
THE NAM/ARW/NMM SUGGESTS REMNANT MCS CONVECTION RIDING DOWN TO THE
SOUTH AND CLIPPING THE WESTERN PORTIONS OF THE CWA. THE
HRRR/WRF/SREF ARE MUCH LESS AGGRESSIVE...WITH THE HRRR SHOWING NO
DEVELOPMENT AT ALL. SO...WHICH SOLUTION WILL BE RIGHT? WHILE A FEW
STORMS HAVE ALREADY FIRED ACROSS THE MTNS OF VA/WV...THIS COULD BE
AN INDICATOR THAT MORE DEVELOPMENT WILL OCCUR THIS AFTN IN A
WELL-HEATED ENVIRONMENT. IF THIS OCCURS...IT WOULD TEND TO RIDE
SOUTH AROUND THE RIDGE TOWARDS THE WESTERN CWA. AT THE SAME TIME
HOWEVER...MID LEVEL RIDGING AND THERMAL ADVECTION WILL WORK AGAINST
THIS...AS SUBSIDENCE AND WEAKENING MID-LEVEL LAPSE RATES SQUELCH
ADVANCING CONVECTION. HAVE CONTINUED SCHC FOR THE WESTERN HALF OF
THE CWA...BUT IT WILL LIKELY BE A DAY WHERE UPDATES NEED TO BE MADE
IN A NOWCAST MANNER AS CONVECTION TRENDS BECOME DETERMINED.
MINS TONIGHT WILL REMAIN WELL ABOVE NORMAL WITH CONTINUED SW WINDS
AND WAA...FALLING ONLY INTO THE MID 70S.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 3 AM WEDNESDAY...THE HOTTEST DAY OF THE YEAR SO FAR
EXPECTED ON THURSDAY. TEMPS WILL SOAR INTO THE MID 90S AS STRONG
WESTERLY DOWNSLOPE FLOW DEVELOPS THROUGH THE LOW LEVELS OF THE
ATMOSPHERE AND RIDGE EXTENDS INTO THE CAROLINAS THROUGH THE MID
TO UPPER LEVELS. MODELS SHOW W WINDS UP TO 30 TO 40 KT JUST ABOVE
THE SURFACE WITH H5 HEIGHTS UP TO 589 DEM. AT THE SAME TIME DEW
POINT TEMPS WILL REMAIN AROUND 70 DEGREES. TEMPS LOOKS LIKE THEY
WILL BE WARMEST ACROSS INLAND AREAS WITH PEAK ACROSS NORTHEAST
SOUTH CAROLINA. THE DEWPOINT TEMPS WILL BE HIGHEST THROUGH THE
MORNING HOURS BUT ONCE MIXING OCCURS READINGS WILL DROP INTO THE
60S INLAND WITH GREATEST VALUES ACROSS GEORGETOWN AND HORRY
COUNTIES IN THE AFTERNOON. THESE TWO COUNTIES WILL MOST LIKELY
SURPASS HEAT ADVISORY CRITERIA WITH APPARENT TEMPERATURES UP ABOVE
105 F...WHILE THE REST OF SOUTH CAROLINA ZONES WILL BE CLOSE.
SOUTHEAST NORTH CAROLINA WILL FEEL CLOSER TO 100 DEGREES F.
AFTER SUCH A WARM AND DRY DAY ON THURSDAY...A COLD FRONT WILL
APPROACH FROM THE NORTHWEST. IT LOOKS LIKE THE BEST DYNAMICS WILL
COME TOGETHER IN THE EVENING HOURS AS A SHORTWAVE PUSHES THE FRONT
EAST ACROSS THE AREA. THE BEST SHORTWAVE ENERGY WILL REMAIN TO OUR
NORTH BUT STILL IMPRESSIVE LIFT AND MOISTURE OVER LOCAL AREA TO
PRODUCE POTENTIAL FOR SEVERE THUNDERSTORMS. CAPE VALUES UP TO 2-3K
J/KG WITH STEEP MID LEVEL LAPSE RATES WILL SUPPORT POTENTIAL FOR
STRONG TO SEVERE STORMS. THE STRONG STEERING FLOW WILL DRIVE
THESE STORMS RAPIDLY THROUGH THE AREA AND OFF THE COAST THROUGH
THE EVENING. THE ONE INHIBITING FACTOR WILL BE THE LOSS OF SURFACE
HEATING ALTHOUGH WITH TEMPS WELL INTO THE 90S IN THE
AFTN...READINGS WILL STILL BE HIGH THROUGH THE EVENING HOURS. ONE
OTHER LIMITING FACTOR WILL BE THE LACK OF GREAT MOISTURE RETURN
FROM THE GULF. THEREFORE EXPECT MOST ACTIVITY TO BE FOCUSED ALONG
AND JUST AHEAD OF FRONTAL BOUNDARY MOVING THROUGH RAPIDLY THROUGH
LATE EVENING. AFTER MIDNIGHT MOST OF THE ACTIVITY WILL MAINLY BE
CONFINED TO COASTAL COUNTIES OR OFF SHORE AS COLD FRONT MOVES
THROUGH. RAPID DRYING WILL FOLLOW WITH PCP WATER VALUES DROPPING
FROM 1.9 INCHES JUST AHEAD AND ALONG COLD FRONT DOWN TO LESS THAN
AN INCH BY DAYBREAK FRIDAY.
DEEP DRY NORTHERLY FLOW WILL KEEP TEMPS IN THE MID 80S FOR HIGHS
ON FRIDAY. THIS COMBINED WITH DEWPOINT TEMPS DOWN A GOOD 10
DEGREES WILL MAKE IT FEEL RELATIVELY COOLER ON FRIDAY. MAY SEE
SOME CU BUILD UP WITH RESIDUAL MOISTURE FROM RAINFALL THE NIGHT
BEFORE BUT OVERALL WILL SEE PLENTY OF SUNSHINE. WINDS WILL WEAKEN
THROUGH THE DAY ON FRI AS HIGH PRESSURE MOVES INTO THE CAROLINAS.
EXPECT DECENT RADIATIONAL COOLING FRI NIGHT WITH TEMPS COOLING
DOWN INTO THE MID 60S.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
AS OF 3 AM WEDNESDAY...HIGH PRESSURE WILL BUILD DOWN OVER THE
CAROLINAS AS MID TO UPPER RIDGE MOVES IN FROM THE WEST. A LIGHT
NORTHERLY FLOW ON FRONT END OF HIGH WILL LIGHTEN AND BECOME MORE
VARIABLE ON SATURDAY AS THE CENTER SHIFTS CLOSER OVERHEAD. A LIGHT
RETURN FLOW WILL SET UP SAT NIGHT INTO SUNDAY AS THE HIGH SHIFTS
OFF SHORE. OVERALL EXPECT SEASONABLE WEATHER WITH PLENTY OF
SUNSHINE AND TEMPS RIGHT AROUND NORMAL...IN THE MID 80S DURING THE
DAY AND MID 60S OVERNIGHT. SFC DEWPOINTS INITIALLY WILL BE LOWER
BUT WILL CREEP UP BY THE END OF THE WEEKEND INTO EARLY NEXT WEEK
PRODUCING SLIGHTLY MORE HUMID WEATHER. PCP WATER VALUES WILL
REMAIN CLOSER TO AN INCH THROUGH THE WEEKEND INTO EARLY NEXT WEEK.
BY LATE MONDAY INTO TUESDAY THE RIDGE ALOFT BEGINS TO BREAK DOWN
AS A SHORTWAVE DIGS DOWN FROM THE GREAT LAKES AND PUSHES A COLD
FRONT EAST BY TUESDAY. DEEPER LAYER MOISTURE WILL SET UP AHEAD OF
THE FRONT WITH PCP WATER VALUES INCREASING UP TO 1.75 INCHES IN A
DEEP SOUTHWESTERLY FLOW. EXPECT MORE ACTIVE WEATHER BY TUES
AFTERNOON AS COLD FRONT APPROACHES. RETURN FLOW NEXT WEEK WILL
LEAD TO TEMPS INCREASING A FEW DEGREES ABOVE CLIMO MON AND TUE.
&&
.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
AS OF 18Z...MODELS ARE NOT IN GOOD AGREEMENT WITH REGARDS TO
CONVECTION THIS AFTERNOON. THE HRRR HAS ABSOLUTELY NOTHING...WHILE
THE WRF AS SCATTERED CONVECTION OVER ABOUT A THIRD OF THE CWA. THINK
THERE WILL BE ISOLATED CB`S...BUT NOT ENOUGH COVERAGE FOR A VCTS
MENTION. SOUTHWEST FLOW WILL BE MORE SOUTH SOUTHWEST AND STRONGER AT
THE COASTAL TERMINALS DUE TO THE RESULTANT. LIGHT WINDS TONIGHT WITH
A REASONABLE CHANCE FOR A COUPLE OF HOURS OF FOG AFTER 09Z.
THURSDAY...CONTINUED SOUTHWEST FLOW WITH MAINLY SCATTERED HIGH
CLOUDS. ANY CONVECTION WILL HOLD OFF UNTIL THE END OF THE FORECAST
VALID PERIOD.
EXTENDED OUTLOOK...ISOLATED SHOWERS/THUNDERSTORMS WITH TEMPO PERIODS
OF MVFR/IFR POSSIBLE THURSDAY EVENING INTO FRIDAY MORNING. MORNING
FOG POSSIBLE SUNDAY AND MONDAY.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 1100 AM WEDNESDAY...CONTINUED SW WINDS AROUND OFFSHORE HIGH
PRESSURE WILL KEEP SW WINDS AND A SW WIND CHOP PREDOMINANT OVER THE
WATERS. SEAS CURRENTLY 2-4 FT WILL REMAIN STATUS QUO THROUGH THE
PERIOD...WITH SW WINDS OF 10-15 KTS PERSISTENT. THE EXCEPTION TO
THIS WILL BE WITHIN THE INNER FEW NM IN THE SEA BREEZE
BOUNDARY...WITH A SLIGHTLY BACKING TO SOUTH WILL OCCUR AS WELL AS AN
INCREASE IN SPEEDS...WITH GUSTS UP TO 20 KTS. SEAS WILL REMAIN 2-4
FT IN THIS ZONE...BUT WILL BECOME MORE CHOPPY THANKS TO SHORTER
PERIODS.
SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 3 AM WEDNESDAY...WINDS WILL INCREASE OUT OF THE SW THROUGH
THURSDAY AS COLD FRONT APPROACHES FROM THE WEST. WINDS WILL START
OUT AROUND 15 KTS BUT WILL REACH UP TO 20 TO 25 KTS THURS EVENING
JUST AHEAD OF THE COLD FRONT. THESE WINDS WILL HELP DRIVE SEAS UP
FROM 2 TO 4 FT EARLY THURS UP TO 4 TO 6 FT THURS EVENING REACHING
SMALL CRAFT CRITERIA LATE THURS AFTN INTO THURSDAY EVENING.
ONCE COLD FRONT CROSSES THE WATERS AFTER MIDNIGHT THURS NIGHT INTO
EARLY FRIDAY...THE WINDS WILL VEER AROUND TO THE NORTHWEST. SEAS
WILL DROP DOWN BELOW SCA QUICKLY OVERNIGHT AND WILL CONTINUE TO
SUBSIDE IN A WEAKENING OFF SHORE FLOW THROUGH FRIDAY. SEAS WILL BE
2 TO 3 FT MOST WATERS BY FRI EVENING.
LONG TERM /SATURDAY THROUGH SUNDAY/...
AS OF 3 AM WEDNESDAY...
HIGH PRESSURE WILL SHIFT CLOSER OVERHEAD ON SATURDAY AND THEN WILL
SHIFT FURTHER OFF THE COAST BY SATURDAY NIGHT INTO SUNDAY.
THEREFORE WINDS WILL VEER AROUND FROM NORTHERLY ON SATURDAY TO
SOUTHERLY BY SUNDAY REMAINING AROUND 10 KT OR LESS. WINDS WILL
SPIKE UP IN SEA BREEZE EACH AFTERNOON IN NEAR SHORE WATERS. SEAS
WILL REMAIN 3 FT OR LESS THROUGH MUCH OF THE WEEKEND.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...JDW
SHORT TERM...RGZ
LONG TERM...RGZ
AVIATION...43/17
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
521 PM EDT WED JUN 12 2013
.SYNOPSIS...
A WARM FRONT WILL BECOME NEARLY STATIONARY ACROSS NORTHERN OHIO AND
NORTHERN PENNSYLVANIA THROUGH THURSDAY MORNING AS LOW PRESSURE MOVES
EAST ALONG THE FRONT. HIGH PRESSURE WILL BUILD SOUTH ACROSS THE AREA
BY SATURDAY MORNING AND TO THE CAROLINA COAST BY SATURDAY NIGHT.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
UPDATED FOR SEVERE WATCH. CONVECTION NOW DEVELOPING IN IOWA AND
ILLINOIS. THIS IS EXPECTED TO DEVELOP INTO A SQUALL LINE THAT WILL
MOVE INTO WESTERN OHIO LATE THIS EVENING TO AROUND MIDNIGHT. IF
CONVECTION DEVELOPS AHEAD OF THE LINE...IT TOO COULD BECOME
SEVERE. THIS IS A PDS WATCH WITH THE EXPECTATION OF THUNDERSTORMS
CONTAINING DAMAGING WINDS IN EXCESS OF 65 KTS. THERMODYNAMICS
BACKS THIS UP WITH DRY AIR ALOFT CONTRIBUTING TO DOWNDRAFT CAPES
OVER 1000K/KG. SHEAR PROFILES ALSO SUGGEST FORWARD PROPAGATION
ADDING TO WIND POTENTIAL. ROTATING SUPERCELLS ALSO SUPPORTED SO
TORNADOES ARE ALSO POSSIBLE.
PREVIOUS...THE WAITING GAME BEGINS. SO FAR ATMOSPHERE APPEARS TO
BE WELL CAPPED AND IS SUPPRESSING CONVECTION FROM DEVELOPING
UPSTREAM. THE OTHER ISSUE AT HAND IS THE EXTENSIVE DEBRIS CLOUDS
HANGING AROUND. WE NEVER CLEARED OUT OR HAD ANY BREAKS IN THE
OVERCAST AS EXPECTED AND THIS IS ALSO LIMITING ANY DEVELOPMENT
OVER THE REGION.
COORDINATED WITH COFORECASTER...IT APPEARS AN AREA OF CONVERGENCE
HAS SET UP BACK OVER EASTERN IOWA AND NORTHWEST ILLINOIS AT THIS
TIME AND THIS COULD VERY WELL BE THE LOCATION THE THUNDERSTORMS
DEVELOP. LATEST HRRR MODEL SHOWS CONVECTION FIRING OVER THIS AREA AS
WELL AND HAS BEEN PRETTY CONSISTENT FROM RUN TO RUN TODAY. THERE IS
THE POSSIBILITY THAT ACTIVITY COULD DEVELOP AHEAD OF THE MAIN LINE
AS INDIVIDUAL CELLS OVERNIGHT.
LATEST SURFACE ANALYSIS SHOWS DEWPOINT TEMPERATURES RISING INTO THE
LOWER 70S INTO THE SOUTHWEST PORTION OF THE FORECAST AREA AT THIS
TIME. WE SHOULD CONTINUE TO SEE A SURGE OF THE HIGHER DEWPOINT AIR
INTO THE FORECAST AREA AS THE EVENING PROGRESSES. THIS WILL HELP TO
INCREASE THE MOISTURE ACROSS THE REGION PRIMING THE ATMOSPHERE FOR
THE POTENTIAL FOR HEAVY RAIN THAT WE HAVE BEEN EXPECTING.
THE SURGE OF STRONG STORMS WILL ENTER THE AREA AND COULD POSSIBLY
EVOLVE INTO AN OVERRUNNING SITUATION ALONG THE STATIONARY FRONT LATE
TONIGHT. THE SEVERE THREAT WILL TRANSITION INTO A POTENTIAL FLOODING
THREAT WITH LOCALLY HEAVY RAIN FROM THE THUNDERSTORMS. THUNDERSTORMS
WILL BE EFFICIENT RAIN PRODUCERS AND AREAS COULD SEE SUBSTANTIAL
PONDING OF WATER OVERNIGHT ALONG WITH THE RAPID RISES OF RIVERS AND
STREAMS. SEE HYDRO SECTION BELOW.
TROPICAL AIR MASS OVER THE REGION WILL BE ACROSS THE SOUTHERN HALF
OF THE FORECAST AREA. NORTHERN HALF OF THE AREA WILL REMAIN NORTH OF
THE STATIONARY FRONT MOST OF THE NIGHT. AS THE LOW PRESSURE SYSTEM
MOVES EAST...IT WILL PUSH THE FRONT NORTH TO THE LAKE SHORE AS A
WARM FRONT. TEMPERATURES OVERNIGHT IN THE LOWER 70S SOUTH AND UPPER
60S IN THE NORTH.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH SATURDAY NIGHT/...
LOW PRESSURE IS PROGGED TO PULL OUT TO THE EAST THURSDAY MORNING AS
UPPER LEVEL AMPLIFIED RIDGE BUILDS EAST FORCING UPPER LEVEL TROUGH
OFF THE COAST. AS SURFACE LOW MOVES EAST...ASSOCIATED MOISTURE AND
SUBSEQUENT PRECIPITATION WILL EXIT TO THE EAST AS WELL. HIGH
PRESSURE AT THE SURFACE PUSHES SOUTHEAST ACROSS THE AREA FORCING
DRIER AIR INTO THE REGION FOR THURSDAY NIGHT INTO FRIDAY.
THE HIGH WILL MOVE SOUTHEAST TO THE CAROLINA COAST BY SATURDAY NIGHT
AND THIS WILL SET UP ANOTHER RETURN SOUTHERLY FLOW TO THE FORECAST
AREA. A FAIRLY FAST MOVING SHORTWAVE TROUGH AND ASSOCIATED MOISTURE
WILL BEGIN TO MOVE EAST INTO THE FORECAST AREA SATURDAY INTO
SATURDAY NIGHT AND COULD BRING ANOTHER ROUND OF SHOWERS TO THE
FORECAST AREA.
COLD AIR ADVECTION ASSOCIATED WITH THE HIGH PRESSURE WILL OCCUR ON
THURSDAY BUT WILL BE SHORT LIVED AS HIGH MOVES TO THE SOUTHEAST. AS
MENTIONED EARLIER...RETURN SOUTHERLY FLOW WILL BRING TEMPERATURES
BACK UP INTO THE MIDDLE 70S EAST AND UPPER 70S TO LOWER 80S WEST BY
SATURDAY. LOWS DIPPING BACK TO THE 50S THURSDAY AND FRIDAY NIGHTS.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
A RIPPLE OF LOW PRESSURE WILL BE MOVING INTO THE REGION ON SUNDAY
WITH SCATTERED THUNDERSTORMS POSSIBLE...ESPECIALLY SUNDAY AFTERNOON.
THE MODELS ARE THEN STRUGGLING WITH THE TIMING OF ANOTHER WAVE THAT
MAY MOVE INTO THE CENTRAL GREAT LAKES ON MONDAY. SO AFTER A BRIEF
LULL IN THUNDERSTORM ACTIVITY LATE SUNDAY NIGHT INTO MONDAY MORNING
WE SHOULD SEE THUNDERSTORM CHANCES RETURN MONDAY AFTERNOON AND
EVENING. THERE MAY BE SOME LINGERING LIGHT SHOWERS OR THUNDERSTORMS
TUESDAY AS HIGH PRESSURE BEGINS TO BUILD INTO THE REGION LATE.
TEMPERATURES THROUGH THE EXTENDED WILL BE WITHIN A FEW DEGREES OF
SEASONAL AVERAGES.
&&
.AVIATION /21Z WEDNESDAY THROUGH MONDAY/...
A WEST TO EAST ORIENTED FRONTAL BOUNDARY WILL REMAIN
QUASISTATIONARY ACROSS CENTRAL OHIO TODAY. A LOW PRESSURE
DISTURBANCE OVER NORTHERN ILLINOIS WILL MAKE ITS WAY EAST ALONG
THIS BOUNDARY TONIGHT...INITIATING THUNDERSTORMS ACROSS THE
FORECAST AREA TONIGHT INTO THURSDAY. THUNDERSTORMS MAY REACH THE
WESTERN TAF SITES SOMETIME AROUND 22Z. THERE IS A CHANCE THAT THIS
DISTURBANCE WILL BECOME FORWARD PROPAGATING...MOVING QUICKLY
THROUGH THE FORECAST AREA. IF THIS OCCURS...A SUBSTANTIAL GUST
FRONT COULD DEVELOP ALONG THE LEADING EDGE OF THE DISTURBANCE.
WILL MONITOR THE THREAT OVER THE NEXT COUPLE OF HOURS TO DETERMINE
WHETHER OR NOT TO ADD A VARIABLE WIND GUST TO TAFS FOR THE 00-04Z
TIME FRAME.
SHOWERS WILL ACCOMPANY THE THUNDERSTORMS THIS EVENING AND WILL
LIKELY PERSIST INTO THURSDAY AS A COLD FRONT MOVES INTO THE AREA.
CEILINGS WILL LOWER TO MVFR OVERNIGHT AND IFR THURSDAY MORNING. MOST
OF THE RAIN WILL OCCUR OVERNIGHT AND EARLY THURSDAY MORNING...WITH
VISIBILITIES DROPPING TO MVFR IN THE HEAVIEST SHOWERS.
CEILINGS WILL BEGIN TO LIFT AND RAIN WILL BEGIN TO CLEAR OUT EARLY
THURSDAY AFTERNOON TOWARDS THE END OF THE TAF PERIOD.
.OUTLOOK...NON VFR CONDITIONS POSSIBLE THURSDAY NIGHT AND SATURDAY
NIGHT AND SUNDAY IN SHOWERS AND THUNDERSTORMS.
&&
.MARINE...
SCATTERED SHOWERS CONTINUE OVER LAKE ERIE THIS AFTERNOON WITH WINDS
VARYING FROM A NORTHEAST TO SOUTHEAST DIRECTION. LATER TONIGHT...A
LOW PRESSURE SYSTEM WILL MOVE EAST ALONG A QUASISTATIONARY BOUNDARY
LYING ACROSS CENTRAL OHIO. SHOWERS AND THUNDERSTORMS WILL
ACCOMPANY THE DISTURBANCE. SOME OF THE THUNDERSTORMS MAY BECOME
SEVERE...WARRANTING A SPECIAL MARINE WARNING.
SHOWERS ARE EXPECTED TO CONTINUE INTO THURSDAY AHEAD OF A COLD
FRONT. MOST OF THE SHOWERS WILL OCCUR OVERNIGHT INTO THURSDAY
MORNING. WINDS WILL INCREASE IN SPEED WITH THE PASSAGE OF THE COLD
FRONT THURSDAY NIGHT. MODELS ARE STILL A BIT UNCERTAIN WITH HOW
STRONG WINDS WILL GET...WHICH WILL AFFECT WAVE HEIGHTS. FOR NOW IT
DOES NOT APPEAR THAT A SMALL CRAFT ADVISORY WILL BE NECESSARY...BUT
THE NEXT FORECAST SHIFT WILL CONTINUE TO MONITOR THE SITUATION.
HIGH PRESSURE WILL BUILD OVER THE LAKE FRIDAY NIGHT AND MOVE EAST
LATE SATURDAY NIGHT. AS THE HIGH MOVES EAST...WINDS WILL TURN TO THE
SOUTHWEST AND PICK UP SPEED. A LOW PRESSURE SYSTEM AND ASSOCIATED
COLD FRONT WILL APPROACH THE AREA ON MONDAY.
&&
.HYDROLOGY...
A FLOOD WATCH IS IN EFFECT FOR THE ENTIRE AREA FROM THE HEAVY
RAINFALL EXPECTED OVERNIGHT AND EARLY THURSDAY. MOISTURE ADVECTION
WILL INCREASE OVER THE AREA THIS AFTERNOON AND NOTABLY OVERNIGHT AS
AN AREA OF LOW PRESSURE MOVES INTO THE REGION FROM THE WEST. THERE
IS SOME INDICATION THAT PRECIPITABLE WATER VALUES COULD REACH 2.0"
WHICH IS ANOMALOUSLY HIGH FOR THIS TIME OF YEAR. THE SHOWERS WILL BE
EFFICIENT RAIN MAKERS AND COULD DROP A QUICK INCH TO AN AREA. THE
THREAT OF TRAINING STORMS IS HIGH SUGGESTING THE THREAT OF A QUICK 2
TO 3 INCHES OF RAIN IS POSSIBLE. RAINFALL RATES THIS HIGH COULD
PRODUCE FLASH FLOODING. THE HEAVIEST RAIN WILL FALL BETWEEN 10 PM
TONIGHT AND 8 AM THURSDAY.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...FLOOD WATCH FROM 10 PM EDT THIS EVENING THROUGH THURSDAY
AFTERNOON FOR OHZ011>014-020>023-031>033-038-089.
FLOOD WATCH THROUGH THURSDAY AFTERNOON FOR OHZ003-006>010-
017>019-027>030-036-037-047.
PA...FLOOD WATCH FROM 10 PM EDT THIS EVENING THROUGH THURSDAY
AFTERNOON FOR PAZ001>003.
MARINE...NONE.
&&
$$
SYNOPSIS...LOMBARDY
NEAR TERM...TK/LOMBARDY
SHORT TERM...LOMBARDY
LONG TERM...MULLEN
AVIATION...MULLEN/YEAGER
MARINE...MULLEN/YEAGER
HYDROLOGY...
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
403 PM EDT WED JUN 12 2013
.SYNOPSIS...
A WARM FRONT WILL BECOME NEARLY STATIONARY ACROSS NORTHERN OHIO AND
NORTHERN PENNSYLVANIA THROUGH THURSDAY MORNING AS LOW PRESSURE MOVES
EAST ALONG THE FRONT. HIGH PRESSURE WILL BUILD SOUTH ACROSS THE AREA
BY SATURDAY MORNING AND TO THE CAROLINA COAST BY SATURDAY NIGHT.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
THE WAITING GAME BEGINS. SO FAR ATMOSPHERE APPEARS TO BE WELL
CAPPED AND IS SUPPRESSING CONVECTION FROM DEVELOPING UPSTREAM. THE
OTHER ISSUE AT HAND IS THE EXTENSIVE DEBRIS CLOUDS HANGING AROUND.
WE NEVER CLEARED OUT OR HAD ANY BREAKS IN THE OVERCAST AS EXPECTED
AND THIS IS ALSO LIMITING ANY DEVELOPMENT OVER THE REGION.
COORDINATED WITH COFORECASTER...IT APPEARS AN AREA OF CONVERGENCE
HAS SET UP BACK OVER EASTERN IOWA AND NORTHWEST ILLINOIS AT THIS
TIME AND THIS COULD VERY WELL BE THE LOCATION THE THUNDERSTORMS
DEVELOP. LATEST HRRR MODEL SHOWS CONVECTION FIRING OVER THIS AREA AS
WELL AND HAS BEEN PRETTY CONSISTENT FROM RUN TO RUN TODAY. THERE IS
THE POSSIBILITY THAT ACTIVITY COULD DEVELOP AHEAD OF THE MAIN LINE
AS INDIVIDUAL CELLS OVERNIGHT.
LATEST SURFACE ANALYSIS SHOWS DEWPOINT TEMPERATURES RISING INTO THE
LOWER 70S INTO THE SOUTHWEST PORTION OF THE FORECAST AREA AT THIS
TIME. WE SHOULD CONTINUE TO SEE A SURGE OF THE HIGHER DEWPOINT AIR
INTO THE FORECAST AREA AS THE EVENING PROGRESSES. THIS WILL HELP TO
INCREASE THE MOISTURE ACROSS THE REGION PRIMING THE ATMOSPHERE FOR
THE POTENTIAL FOR HEAVY RAIN THAT WE HAVE BEEN EXPECTING.
THE SURGE OF STRONG STORMS WILL ENTER THE AREA AND COULD POSSIBLY
EVOLVE INTO AN OVERRUNNING SITUATION ALONG THE STATIONARY FRONT LATE
TONIGHT. THE SEVERE THREAT WILL TRANSITION INTO A POTENTIAL FLOODING
THREAT WITH LOCALLY HEAVY RAIN FROM THE THUNDERSTORMS. THUNDERSTORMS
WILL BE EFFICIENT RAIN PRODUCERS AND AREAS COULD SEE SUBSTANTIAL
PONDING OF WATER OVERNIGHT ALONG WITH THE RAPID RISES OF RIVERS AND
STREAMS. SEE HYDRO SECTION BELOW.
TROPICAL AIR MASS OVER THE REGION WILL BE ACROSS THE SOUTHERN HALF
OF THE FORECAST AREA. NORTHERN HALF OF THE AREA WILL REMAIN NORTH OF
THE STATIONARY FRONT MOST OF THE NIGHT. AS THE LOW PRESSURE SYSTEM
MOVES EAST...IT WILL PUSH THE FRONT NORTH TO THE LAKE SHORE AS A
WARM FRONT. TEMPERATURES OVERNIGHT IN THE LOWER 70S SOUTH AND UPPER
60S IN THE NORTH.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH SATURDAY NIGHT/...
LOW PRESSURE IS PROGGED TO PULL OUT TO THE EAST THURSDAY MORNING AS
UPPER LEVEL AMPLIFIED RIDGE BUILDS EAST FORCING UPPER LEVEL TROUGH
OFF THE COAST. AS SURFACE LOW MOVES EAST...ASSOCIATED MOISTURE AND
SUBSEQUENT PRECIPITATION WILL EXIT TO THE EAST AS WELL. HIGH
PRESSURE AT THE SURFACE PUSHES SOUTHEAST ACROSS THE AREA FORCING
DRIER AIR INTO THE REGION FOR THURSDAY NIGHT INTO FRIDAY.
THE HIGH WILL MOVE SOUTHEAST TO THE CAROLINA COAST BY SATURDAY NIGHT
AND THIS WILL SET UP ANOTHER RETURN SOUTHERLY FLOW TO THE FORECAST
AREA. A FAIRLY FAST MOVING SHORTWAVE TROUGH AND ASSOCIATED MOISTURE
WILL BEGIN TO MOVE EAST INTO THE FORECAST AREA SATURDAY INTO
SATURDAY NIGHT AND COULD BRING ANOTHER ROUND OF SHOWERS TO THE
FORECAST AREA.
COLD AIR ADVECTION ASSOCIATED WITH THE HIGH PRESSURE WILL OCCUR ON
THURSDAY BUT WILL BE SHORT LIVED AS HIGH MOVES TO THE SOUTHEAST. AS
MENTIONED EARLIER...RETURN SOUTHERLY FLOW WILL BRING TEMPERATURES
BACK UP INTO THE MIDDLE 70S EAST AND UPPER 70S TO LOWER 80S WEST BY
SATURDAY. LOWS DIPPING BACK TO THE 50S THURSDAY AND FRIDAY NIGHTS.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
A RIPPLE OF LOW PRESSURE WILL BE MOVING INTO THE REGION ON SUNDAY
WITH SCATTERED THUNDERSTORMS POSSIBLE...ESPECIALLY SUNDAY AFTERNOON.
THE MODELS ARE THEN STRUGGLING WITH THE TIMING OF ANOTHER WAVE THAT
MAY MOVE INTO THE CENTRAL GREAT LAKES ON MONDAY. SO AFTER A BRIEF
LULL IN THUNDERSTORM ACTIVITY LATE SUNDAY NIGHT INTO MONDAY MORNING
WE SHOULD SEE THUNDERSTORM CHANCES RETURN MONDAY AFTERNOON AND
EVENING. THERE MAY BE SOME LINGERING LIGHT SHOWERS OR THUNDERSTORMS
TUESDAY AS HIGH PRESSURE BEGINS TO BUILD INTO THE REGION LATE.
TEMPERATURES THROUGH THE EXTENDED WILL BE WITHIN A FEW DEGREES OF
SEASONAL AVERAGES.
&&
.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
A WEST TO EAST ORIENTED FRONTAL BOUNDARY WILL REMAIN
QUASISTATIONARY ACROSS CENTRAL OHIO TODAY. A LOW PRESSURE
DISTURBANCE OVER NORTHERN ILLINOIS WILL MAKE ITS WAY EAST ALONG
THIS BOUNDARY TONIGHT...INITIATING THUNDERSTORMS ACROSS THE
FORECAST AREA TONIGHT INTO THURSDAY. THUNDERSTORMS MAY REACH THE
WESTERN TAF SITES SOMETIME AROUND 22Z. THERE IS A CHANCE THAT THIS
DISTURBANCE WILL BECOME FORWARD PROPAGATING...MOVING QUICKLY
THROUGH THE FORECAST AREA. IF THIS OCCURS...A SUBSTANTIAL GUST
FRONT COULD DEVELOP ALONG THE LEADING EDGE OF THE DISTURBANCE.
WILL MONITOR THE THREAT OVER THE NEXT COUPLE OF HOURS TO DETERMINE
WHETHER OR NOT TO ADD A VARIABLE WIND GUST TO TAFS FOR THE 00-04Z
TIME FRAME.
SHOWERS WILL ACCOMPANY THE THUNDERSTORMS THIS EVENING AND WILL
LIKELY PERSIST INTO THURSDAY AS A COLD FRONT MOVES INTO THE AREA.
CEILINGS WILL LOWER TO MVFR OVERNIGHT AND IFR THURSDAY MORNING. MOST
OF THE RAIN WILL OCCUR OVERNIGHT AND EARLY THURSDAY MORNING...WITH
VISIBILITIES DROPPING TO MVFR IN THE HEAVIEST SHOWERS.
CEILINGS WILL BEGIN TO LIFT AND RAIN WILL BEGIN TO CLEAR OUT EARLY
THURSDAY AFTERNOON TOWARDS THE END OF THE TAF PERIOD.
.OUTLOOK...NON VFR CONDITIONS POSSIBLE THURSDAY NIGHT AND SATURDAY
NIGHT AND SUNDAY IN SHOWERS AND THUNDERSTORMS.
&&
.MARINE...
SCATTERED SHOWERS CONTINUE OVER LAKE ERIE THIS AFTERNOON WITH WINDS
VARYING FROM A NORTHEAST TO SOUTHEAST DIRECTION. LATER TONIGHT...A
LOW PRESSURE SYSTEM WILL MOVE EAST ALONG A QUASISTATIONARY BOUNDARY
LYING ACROSS CENTRAL OHIO. SHOWERS AND THUNDERSTORMS WILL
ACCOMPANY THE DISTURBANCE. SOME OF THE THUNDERSTORMS MAY BECOME
SEVERE...WARRANTING A SPECIAL MARINE WARNING.
SHOWERS ARE EXPECTED TO CONTINUE INTO THURSDAY AHEAD OF A COLD
FRONT. MOST OF THE SHOWERS WILL OCCUR OVERNIGHT INTO THURSDAY
MORNING. WINDS WILL INCREASE IN SPEED WITH THE PASSAGE OF THE COLD
FRONT THURSDAY NIGHT. MODELS ARE STILL A BIT UNCERTAIN WITH HOW
STRONG WINDS WILL GET...WHICH WILL AFFECT WAVE HEIGHTS. FOR NOW IT
DOES NOT APPEAR THAT A SMALL CRAFT ADVISORY WILL BE NECESSARY...BUT
THE NEXT FORECAST SHIFT WILL CONTINUE TO MONITOR THE SITUATION.
HIGH PRESSURE WILL BUILD OVER THE LAKE FRIDAY NIGHT AND MOVE EAST
LATE SATURDAY NIGHT. AS THE HIGH MOVES EAST...WINDS WILL TURN TO THE
SOUTHWEST AND PICK UP SPEED. A LOW PRESSURE SYSTEM AND ASSOCIATED
COLD FRONT WILL APPROACH THE AREA ON MONDAY.
&&
.HYDROLOGY...
A FLOOD WATCH IS IN EFFECT FOR THE ENTIRE AREA FROM THE HEAVY
RAINFALL EXPECTED OVERNIGHT AND EARLY THURSDAY. MOISTURE ADVECTION
WILL INCREASE OVER THE AREA THIS AFTERNOON AND NOTABLY OVERNIGHT AS
AN AREA OF LOW PRESSURE MOVES INTO THE REGION FROM THE WEST. THERE
IS SOME INDICATION THAT PRECIPITABLE WATER VALUES COULD REACH 2.0"
WHICH IS ANOMALOUSLY HIGH FOR THIS TIME OF YEAR. THE SHOWERS WILL BE
EFFICIENT RAIN MAKERS AND COULD DROP A QUICK INCH TO AN AREA. THE
THREAT OF TRAINING STORMS IS HIGH SUGGESTING THE THREAT OF A QUICK 2
TO 3 INCHES OF RAIN IS POSSIBLE. RAINFALL RATES THIS HIGH COULD
PRODUCE FLASH FLOODING. THE HEAVIEST RAIN WILL FALL BETWEEN 10 PM
TONIGHT AND 8 AM THURSDAY.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...FLOOD WATCH FROM 10 PM EDT THIS EVENING THROUGH THURSDAY
AFTERNOON FOR OHZ011>014-020>023-031>033-038-089.
FLOOD WATCH THROUGH THURSDAY AFTERNOON FOR OHZ003-006>010-
017>019-027>030-036-037-047.
PA...FLOOD WATCH FROM 10 PM EDT THIS EVENING THROUGH THURSDAY
AFTERNOON FOR PAZ001>003.
MARINE...NONE.
&&
$$
SYNOPSIS...LOMBARDY
NEAR TERM...LOMBARDY
SHORT TERM...LOMBARDY
LONG TERM...MULLEN
AVIATION...MULLEN/YEAGER
MARINE...MULLEN/YEAGER
HYDROLOGY...JAMISON
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
1244 PM EDT WED JUN 12 2013
.SYNOPSIS...
LOW PRESSURE WILL MOVE ALONG A FRONT STALLED OVER THE AREA TONIGHT
AND THURSDAY MORNING. HIGH PRESSURE WILL SLIDE SOUTHEAST THROUGH THE
GREAT LAKES FRIDAY THROUGH SATURDAY AND TO THE CAROLINA COAST
SUNDAY. ANOTHER LOW WILL MOVE EAST ACROSS THE LAKES SUNDAY AND
MONDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
TEMPERATURES CONTINUE TO SURGE UPWARD AS BREAKS IN THE OVERCAST
ALLOW FOR HEATING TO TAKE PLACE AT THIS TIME. CURRENT TEMPERATURES
ARE IN THE UPPER 70S WEST AND LOWER TO MIDDLE 70S ELSEWHERE. DEW
POINT TEMPERATURES ARE ALSO CLIMBING WITH EXPECTED SURFACE VALUES
IN THE LOWER 70S WEST BY LATE THIS AFTERNOON AND UPPER 60S
ELSEWHERE. ALL IN ALL THIS SCENARIO IS SHAPING UP TO BE A VERY
MOIST ENVIRONMENT TO FEED THE CONVECTION ALONG WITH ANY
INTERACTIONS WITH THE STATIONARY FRONT IN PLACE. SIGNIFICANT
RAINFALL TOTALS STILL APPEAR LIKELY ACROSS THE AREA. WARM CLOUD
DEPTH IS FAIRLY SHALLOW THROUGH DAY AT AROUND 9000 FEET BUT
INCREASES TO OVER 12000 FEET LATER TONIGHT MAKING THUNDERSTORMS
VERY EFFICIENT RAIN PRODUCERS.
AS FAR AS SEVERE WEATHER THREAT GOES...HIGH RISK SEVERE WEATHER
REMAINS WEST OF THE FORECAST AREA BUT OUR WESTERN PORTIONS REMAIN
IN THE MODERATE RISK AND A SLIGHT RISK ELSEWHERE. THE BOTTOM
LINE IS THAT SIGNIFICANT WEATHER CAN BE EXPECTED THIS EVENING INTO
TONIGHT WITH SEVERE THREATS STILL BEING HIGH WINDS AND HAIL. STILL
CANT RULE OUT TORNADOES AS A THREAT AS WELL AS SURFACE LOW
PRESSURE MOVES EAST ACROSS THE REGION.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY NIGHT/...
THIS LOOKS TO BE ONE OF THE BEST SETUPS FOR A CONVECTIVE COMPLEX TO
WORK ACROSS THE CWA THAT WE`VE SEEN IN A WHILE. NOT SAYING THERE
WILL BE A DERECHO BUT THE POSSIBILITY IS THERE. TRACK OF THE CORE OF
THE CONVECTION HAS BEEN CONSISTENT FOR SEVERAL DAYS SO WILL STAY
WITH POPS 90 PERCENT OR BETTER AT SOME POINT TONIGHT INTO THU
MORNING FOR THE WHOLE CWA.
WITH P/W`S RUNNING CLOSE TO 2 INCHES FOR MOST OF THE AREA SEE NO
REASON NOT TO HAVE A FLOOD WATCH GOING. ENOUGH QPF STILL SHOWN FOR
THU MORNING TO SLOW POP DRAW DOWN SOME.
QUESTION WHETHER THINGS WILL BE ABLE TO RECOVER FROM MORNING PRECIP
AND CLOUDS TO ALLOW AIR MASS TO DESTABILIZE ENOUGH FOR SOME WIDELY
SCT AFTERNOON CONVECTION TO DEVELOP. GFS HAS BEEN CONSISTENTLY
TRYING TO REDEVELOP SOME SHRA OVER THE WEST THU AFTERNOON AS A
RESULT OF FORCING FROM PRESENCE OF UPPER TROUGH. COOLER FLOW OUT OF
THE NORTH BEHIND THE LOW THU AFTERNOON...ALONG WITH GENERAL
SUBSIDENCE AND DRIER AIR WOULD SEEM TO MAKE IT FAIRLY TOUGH TO ALLOW
FOR MUCH CONVECTION TO DEVELOP. GUIDANCE POPS FOR 18Z THRU 00Z THU
EVE VERY LOW AND THIS SEEM TO MAKE SENSE SO WILL LOWER POPS.
UPPER TROUGH SLOWS JUST EAST OF THE AREA THU NIGHT INTO FRI. WRAP
MOISTURE CONTINUES TO BE SHOWN ROTATING SOUTH ACROSS THE EASTERN
PART OF THE CWA THU NIGHT AND FRI. WILL KEEP SMALL CHANCE FOR SHRA
GOING. THINK THE SHRA SHOULD BE DONE BY FRI EVENING BUT WILL KEEP A
SLIGHT CHANCE FOR THE INLAND EAST FOR THE EARLY PART OF FRI EVE TO
GIVE ANY LINGERING CONVECTIVE SHRA A FEW HOURS TO DIE OFF.
WITH CLOUDS LIKELY TO BE OVER THE EAST THU NIGHT WILL ADJUST LOWS UP
A LITTLE MORE.
SOME HIGH CLOUDS MAY BE SPREADING INTO THE AREA LATER FRI NIGHT BUT
STILL SHOULD SEE ENOUGH CLOUD FREE TIME FOR DECENT RADIATIONAL
COOLING TO TAKE PLACE AS THE HIGH MOVES OVERHEAD. LOWS MOST PLACES
LOOK TO BE SEASONALLY COOL WITH READINGS MOSTLY DOWN INTO A 48 TO 55
RANGE.
PROGRESSIVE UPPER FLOW WILL HELP SURFACE HIGH OFF TO THE EAST BY
LATE SAT. MODELS BRING A WEAK UPPER DISTURBANCE INTO THE AREA BY SAT
EVENING. WARM FRONT LIFTING NEAR LERI WILL PROVIDE FOCUS FOR
CONVECTION TO SLIDE SE INTO THE AREA SO WILL INCREASE POP FOR SAT
AFTERNOON AND NIGHT.
&&
.LONG TERM /SUNDAY THROUGH TUESDAY/...
A THREAT OF SHOWERS AND THUNDERSTORMS FOR MUCH OF THIS FORECAST
PERIOD. A THREAT SUNDAY AHEAD OF THE FRONT WHICH WILL MOVE ACROSS
THE AREA SUNDAY NIGHT INTO MONDAY. CONTINUING THE THREAT INTO
TUESDAY WITH AN UPPER TROF ACROSS THE REGION EVEN THOUGH HIGH
PRESSURE IS BUILDING IN AT THE SURFACE. THAT MEANS IT MAY BE MORE
DIURNAL IN NATURE. WENT CLOSE TO WPC FOR THE TEMPERATURE FORECAST.
&&
.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
HIGH PRESSURE OVER THE AREA WITH A DIFFUSE STATIONARY BOUNDARY
WEST TO EAST ACROSS CENTRAL OHIO. THE MORNING ISSUES ARE SOME
PATCHY FOG ACROSS THE FORECAST AREA AND STRATUS FOR NW PA. THEY
WILL BOTH BURN OFF OR RAISE SOMEWHAT RAPIDLY THIS MORNING. SOME
SHOWERS ARE OVER NORTHWEST OHIO AND I AM GOING WITH THEY WILL
DISSIPATE AS THEY MOVE EAST.
OTHERWISE THE ISSUE IS THE TIMING AND STRENGTH OF THE
THUNDERSTORMS FOR THE LATE AFTERNOON AND EVENING. MANY MODELS
INDICATE THE SHOWERS AND THUNDERSTORMS WON`T GET GOING UNTIL AFTER
DARK...WHILE THE HRRR AND THE RUC/RAP STARTS THE SHOWERS AND
THUNDERSTORMS AFTER 21Z. ON THE EDGE ABOUT THAT...TRIED TO LEAN
TOWARD THE MOST SIGNIFICANT SHOWERS AND THUNDERSTORMS OCCURRING DURING
THE OVERNIGHT HOURS AS THE SURFACE LOW MOVES ALONG THE BOUNDARY.
IT SHOULD BE SEVERAL WAVES OF PRECIPITATION. OCCASIONAL
IFR...MAINLY IN THE VISIBILITY AND EVENTUALLY AFTER THE SURFACE
LOW MOVES EAST IFR CEILINGS IN THE NORTHERLY FLOW. WIDESPREAD
STRONG WINDS COULD BE ASSOCIATED WITH THE THUNDERSTORMS IF THEY
FORM A LINE. ALL THIS WILL HAVE TO BE MONITORED.
.OUTLOOK...NON VFR CONDITIONS THURSDAY AND POSSIBLY CONTINUING INTO
THURSDAY NIGHT AND SATURDAY NIGHT AND SUNDAY IN SHOWERS AND THUNDERSTORMS.
&&
.MARINE...
HIGH PRESSURE OVER THE AREA TO START WITH A STATIONARY FRONT WELL
SOUTH OF LAKE ERIE. A LOW WILL MOVE ALONG THE FRONT AND THAT WILL
INCREASE THE WINDS TONIGHT AND THURSDAY...IN THE MEANTIME THE WINDS
WILL BE LIGHT AND VARIABLE. SOME QUESTION HOW CLOSE THE LOW WILL
TRACK TO THE LAKE...WENT MORE WITH THE GFS WHICH TRACKS THE LOW A
LITTLE FARTHER FROM THE LAKE SO THE WINDS MAY BE STRONGER. A SMALL
CRAFT ADVISORY MAY BE NEEDED BY DAYBREAK THURSDAY AND THE THREAT
WILL CONTINUE INTO THURSDAY NIGHT. SPECIAL MARINE WARNINGS MAY BE
NEEDED MAINLY THIS EVENING AND TONIGHT FOR LAKE ERIE.
HIGH PRESSURE WILL BUILD OVER LAKE ERIE FRIDAY NIGHT AND MOVE EAST
SATURDAY NIGHT ALLOWING A SOUTHWEST FLOW TO DEVELOP. THE FLOW WILL
BE STRONG AND THAT MAY CAUSE WAVES TO BE 2 TO 4 FEET ON THE EAST END
OF THE LAKE. OTHERWISE THE NEXT SIGNIFICANT THREAT FOR A SMALL CRAFT
ADVISORY WILL BE EARLY NEXT WEEK WHEN A COLD FRONT MOVES ACROSS THE
AREA.
&&
.HYDROLOGY...
A FLOOD WATCH IS IN EFFECT FOR THE ENTIRE AREA FROM THE HEAVY
RAINFALL EXPECTED OVERNIGHT AND EARLY THURSDAY. MOISTURE ADVECTION
WILL INCREASE OVER THE AREA THIS AFTERNOON AND NOTABLY OVERNIGHT AS
AN AREA OF LOW PRESSURE MOVES INTO THE REGION FROM THE WEST. THERE
IS SOME INDICATION THAT PRECIPITABLE WATER VALUES COULD REACH 2.0"
WHICH IS ANOMALOUSLY HIGH FOR THIS TIME OF YEAR. THE SHOWERS WILL BE
EFFICIENT RAIN MAKERS AND COULD DROP A QUICK INCH TO AN AREA. THE
THREAT OF TRAINING STORMS IS HIGH SUGGESTING THE THREAT OF A QUICK 2
TO 3 INCHES OF RAIN IS POSSIBLE. RAINFALL RATES THIS HIGH COULD
PRODUCE FLASH FLOODING. THE HEAVIEST RAIN WILL FALL BETWEEN 10 PM
TONIGHT AND 8 AM THURSDAY.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...FLOOD WATCH FROM 10 PM EDT THIS EVENING THROUGH THURSDAY
AFTERNOON FOR OHZ011>014-020>023-031>033-038-089.
FLOOD WATCH FROM 6 PM EDT THIS EVENING THROUGH THURSDAY
AFTERNOON FOR OHZ003-006>010-017>019-027>030-036-037-047.
PA...FLOOD WATCH FROM 10 PM EDT THIS EVENING THROUGH THURSDAY
AFTERNOON FOR PAZ001>003.
MARINE...NONE.
&&
$$
SYNOPSIS...ADAMS
NEAR TERM...LOMBARDY
SHORT TERM...ADAMS
LONG TERM...KIELTYKA
AVIATION...KIELTYKA
MARINE...KIELTYKA
HYDROLOGY...JAMISON
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
432 PM EDT WED JUN 12 2013
.SYNOPSIS...
HIGH PRESSURE WILL MAINTAIN WARM TEMPERATURES ACROSS THE REGION
TODAY AHEAD OF AN APPROACHING COLD FRONT...WHICH WILL CROSS THE AREA
ON THURSDAY. DRY HIGH PRESSURE WILL BUILD IN FROM THE NORTH
FRIDAY...MAKING FOR A MOSTLY DRY WEEKEND. THE NEXT COLD FRONT WILL
APPROACH THE REGION EARLY NEXT WEEK...TRIGGERING AFTERNOON SHOWERS
AND THUNDERSTORMS EACH DAY THROUGH MIDWEEK.
&&
.NEAR TERM /THROUGH THURSDAY/...
AS OF 430 PM...THERE WAS A PROBLEM WITH THE PREVIOUS FORECAST. HAVE
FIXED THIS SO THE NEW DAY 7 PERIOD IS INCLUDED. CONVECTION STILL HAS
NOT DEVELOPED OVER THE CWFA DESPITE THE VERY HIGH CAPE AND UNCAPPED
ATMOS. THIS EVEN WITH A WEAK LEE TROF IN PLACE. IN FACT...THE ONLY
PRECIP IS LIGHT SHRA FROM FALLING FROM A MID CLOUD DECK OVER THE NC
AND ERN SC PIEDMONT. GIVEN THAT THE PREVIOUS THINKING IS STILL
VALID...KEPT POP AS IS BUT TRIMMED THE START TIME AND KEPT POP OVER
NC ISOLATED. OTHERWISE... MAIN UPDATES WERE FOR CURRENT CONDITIONS.
AS OF 230 PM...SPC MESOANAL PAGE SHOWS OVER 3000J/KG OF SBCAPE ACROSS
THE REGION WITH NO CIN. WILL CONTINUE THE IDEA PER HRRR/4KM EMC WRF
AND HI-RES WRF THAT SCT THUNDERSTORMS WILL DEVELOP OVER THE WESTERN
UPSTATE/NE GA BY LATE AFTERNOON TRIGGERED BY A MID LEVEL VORT. THE
ENTIRE AREA IS INCLUDED IN A SPC SLGT RISK AREA. THIS MAKES SENSE IN
THAT ANY STORMS THAT DEVELOP HAVE THE POTENTIAL TO PRODUCE LOCALIZED
DAMAGING WINDS PER THE 900J OF DCAPE ANALYZED BY SPC. CONVECTION IS
EXPECTED TO MOVE OUT OF THE AREA BY 00Z.
THE OVERNIGHT SHOULD BE QUIET AS A WEAK RIDGE OF HIGH PRESSURE NOSES
EASTWARD INTO THE AREA. HOWEVER...WE WILL BE KEEPING AN EYE UPSTREAM
OVER THE LOWER GREAT LAKES WHERE A CONVECTIVE COMPLEX IS EXPECTED
TO DEVELOP AND PERHAPS TRANSITION INTO A DERECHO AS IT MOVES SE
THROUGH THE OHIO VALLEY AND INTO THE APPALACHIANS. THE 4KM EMC WRF
SHOWS THIS FEATURE MAKING A RUN AT THE NC MOUNTAINS LATE
TONIGHT...THEN DISSIPATING IT AS IT HITS THE MOUNTAINS. HAVE BUMPED
SOME CHC POPS UP TO ABOUT 12Z OVER THE NC BORDER COUNTIES TO ACCOUNT
FOR THIS. CAN`T RULE OUT SOME GUSTY WINDS REACHING THE AREA THU
MORNING FROM DERECHO OUTFLOW...BUT DO NOT HAVE THAT POSSIBILITY
CODED INTO THE GRIDS. IT WILL BE A WARM AND MUGGY NIGHT WITH LOWS
NOT GETTING OUT OF THE 70S FOR MOST AREAS EAST OF THE MOUNTAINS.
ON THU...A COLD FRONT IS STILL EXPECTED TO ARRIVE AND MOVE ACROSS
THE AREA DURING THE COURSE OF THE DAY. WIND FIELDS WILL BE IMPROVING
WITH 0-6KM BULK SHEAR INCREASING TO 35-40KT AND CAPES >2500J.
HENCE...SVR STORMS ARE CERTAINLY POSSIBLE PER THE SPC DAY 2 OUTLOOK.
LOOKS LIKE THE BEST THREAT FOR SEVERE STORMS WILL BE OVER THE
PIEDMONT IN THE MID TO LATE AFTERNOON HOURS. WINDS THROUGH THE
COLUMN WILL TAKE ON A DOWNSLOPE COMPONENT ON THU SO IT IS POSSIBLE
THAT COVERAGE ESPECIALLY ACROSS THE UPSTATE PERHAPS WILL NOT BE
100%. HENCE...POPS ARE HIGHEST ACROSS THE SOUTHERN PIEDMONT AREAS.
IT WILL BE ANOTHER HOT DAY ON THU WITH A MODEL BLEND PRODUCING HIGHS
IN THE 90-95 RANGE OUTSIDE THE MOUNTAINS AND MID 80S MOUNTAIN
VALLEYS.
&&
.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY/...
AS OF 130 PM EDT WEDNESDAY...EXPECT QUIET AND COOLER CONDITIONS FOR
THE SHORT TERM PERIOD. CONDITIONS QUICKLY DRY OUT THURSDAY EVENING
AS A SHARP UPPER TROUGH AXIS AND ASSOCIATED SURFACE COLD FRONT PUSH
EAST OF THE AREA. HOWEVER...SCATTERED LIGHT SHOWERS MAY CONTINUE
ACROSS THE NC MTNS THROUGH LATE THURSDAY NIGHT DUE TO INCREASING NW
UPSLOPE FLOW ALONG WITH THE PASSAGE OF WEAK UPPER DPVA THERE.
AN UPPER RIDGE OF H5 HIGH WILL REMAIN ANCHORED OVER THE SOUTHCENTRAL
STATES LEAVING OUR FORECAST AREA UNDER THE NW FLOW ALOFT FRI/SAT.
THIS WILL ALLOW CANADIAN SURFACE HIGH PRESSURE TO RIDGE SOUTH INTO
THE FORECAST AREA PROVIDING DRY NORTHERLY FLOW THROUGH THE PERIOD.
TEMPERATURES WILL BE AROUND 2-3 DEGREES BELOW NORMAL WITH HIGHS IN
THE LOWER TO MID 80S OVER THE PIEDMONT AND 70S IN THE HIGHER
TERRAIN.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
AS OF 2PM WEDNESDAY...THE MODELS REMAIN IN FAIRLY GOOD AGREEMENT
THROUGH MOST OF THE PERIOD. AFTER A PREDOMINANTLY DRY WEEKEND...THE
RIDGE OVER THE EASTERN CONUS WILL BREAK DOWN BY THE BEGINNING OF
NEXT WEEK. A WEAK TROUGH WILL THEN SET UP OVER THE SOUTHEASTERN
CONUS AND ALLOW A MORE UNSETTLED SUMMERTIME PATTERN TO RETURN. THE
NEXT FRONTAL SYSTEM APPROACHES LATE MONDAY/EARLY TUESDAY...RESULTING
IN DIURNAL CHANCE POPS FOR THE ENTIRE CWA ON MONDAY. THE FRONT
PASSES AND STALLS OUT JUST TO THE SOUTH OF THE FORECAST AREA LATE
TUESDAY...SO CHANCE POPS CONTINUE FOR THE ENTIRE FORECAST AREA
THROUGH MIDWEEK. TEMPERATURES WILL REMAIN NEAR NORMAL THROUGH THE
EXTENDED PERIOD.
&&
.AVIATION /21Z WEDNESDAY THROUGH MONDAY/...
AT KCLT...VFR THROUGH THE FORECAST PERIOD. SPC MESOANAL PAGE STILL
SHOWS SOME CONVECTIVE INHIBITION. ALSO...CONVECTION ALLOWING MODELS
SHOWING DEEP CONVECTION DEVELOPING WELL WEST OF THE AIRFIELD CLOSER
TO THE WEAK FORCING ASSOCIATED WITH A MID LEVEL VORT. HENCE...HAVE
NOT INCLUDED ANY TSRA...BUT WILL MONITOR RADAR TRENDS CLOSELY. COLD
FRONT ON THU WILL AFFECT THE AREA IN THE AFTERNOON WITH A TIMEFRAME
AFTER THE VALID TIME OF THIS TAF. HOWEVER...SW WINDS WILL INCREASE
AHEAD OF THE FRONT PRIOR TO 18Z THU.
ELSEWHERE...MAIN QUESTION IS WHERE...IF ANY DEEP CONVECTION WILL
DEVELOP THIS AFTERNOON. LATEST HRRR AND HI-RES WRF INDICATE
CONVECTION DEVELOPING BY LATE AFTERNOON OVER THE WESTERN UPSTATE. AM
NOT CONFIDENT ENOUGH IN LOCATION TO ADD A TEMPO...BUT WILL ADD VCTS
TO THE KGMU...KGSP AND KAND TAFS. IT WILL THEN BE QUIET AND VFR
AFTER 00Z. A COLD FRONT WILL AFFECT THE AREA ON THU BUT AFTER
18Z. GUSTY SW WINDS WILL INCREASE AHEAD OF THE FRONT.
OUTLOOK...A COLD FRONT WILL BRING A GOOD CHANCE OF SHOWERS AND
THUNDERSTORMS TO THE REGION ON THURSDAY AFTERNOON WITH GUSTY WINDS
AND HAIL POSSIBLE.. HIGH PRESSURE WILL BUILD IN BEHIND THE FRONT AND
PRODUCE GENERALLY QUIET WEATHER AND VFR CONDITIONS THROUGH THE
WEEKEND.
CONFIDENCE TABLE...
20-02Z 02-08Z 08-14Z 14-20Z
KCLT HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KGSP HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAVL HIGH 100% HIGH 100% HIGH 88% HIGH 100%
KHKY HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KGMU HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAND HIGH 100% HIGH 100% HIGH 94% 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...VISIN
NEAR TERM...LG/RWH
SHORT TERM...JOH
LONG TERM...ARK/VISIN
AVIATION...LG
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
244 PM EDT WED JUN 12 2013
.SYNOPSIS...
HIGH PRESSURE WILL MAINTAIN WARM TEMPERATURES ACROSS THE REGION
TODAY AHEAD OF AN APPROACHING COLD FRONT...WHICH WILL CROSS THE AREA
ON THURSDAY. DRY HIGH PRESSURE WILL BUILD IN FROM THE NORTH
FRIDAY...MAKING FOR A MOSTLY DRY WEEKEND. THE NEXT COLD FRONT WILL
APPROACH THE REGION EARLY NEXT WEEK...TRIGGERING AFTERNOON SHOWERS
AND THUNDERSTORMS EACH DAY THROUGH MIDWEEK.
&&
.NEAR TERM /THROUGH THURSDAY/...
AS OF 230 PM...SPC MESOANAL PAGE SHOWS OVER 3000J/KG OF SBCAPE
ACROSS THE REGION WITH NO CIN. WILL CONTINUE THE IDEA PER HRRR/4KM
EMC WRF AND HI-RES WRF THAT SCT THUNDERSTORMS WILL DEVELOP OVER
THE WESTERN UPSTATE/NE GA BY LATE AFTERNOON TRIGGERED BY A MID
LEVEL VORT. THE ENTIRE AREA IS INCLUDED IN A SPC SLGT RISK AREA.
THIS MAKES SENSE IN THAT ANY STORMS THAT DEVELOP HAVE THE
POTENTIAL TO PRODUCE LOCALIZED DAMAGING WINDS PER THE 900J OF
DCAPE ANALYZED BY SPC. CONVECTION IS EXPECTED TO MOVE OUT OF THE
AREA BY 00Z.
THE OVERNIGHT SHOULD BE QUIET AS A WEAK RIDGE OF HIGH PRESSURE NOSES
EASTWARD INTO THE AREA. HOWEVER...WE WILL BE KEEPING AN EYE UPSTREAM
OVER THE LOWER GREAT LAKES WHERE A CONVECTIVE COMPLEX IS EXPECTED
TO DEVELOP AND PERHAPS TRANSITION INTO A DERECHO AS IT MOVES SE
THROUGH THE OHIO VALLEY AND INTO THE APPALACHIANS. THE 4KM EMC WRF
SHOWS THIS FEATURE MAKING A RUN AT THE NC MOUNTAINS LATE
TONIGHT...THEN DISSIPATING IT AS IT HITS THE MOUNTAINS. HAVE BUMPED
SOME CHC POPS UP TO ABOUT 12Z OVER THE NC BORDER COUNTIES TO ACCOUNT
FOR THIS. CAN`T RULE OUT SOME GUSTY WINDS REACHING THE AREA THU
MORNING FROM DERECHO OUTFLOW...BUT DO NOT HAVE THAT POSSIBILITY
CODED INTO THE GRIDS. IT WILL BE A WARM AND MUGGY NIGHT WITH LOWS
NOT GETTING OUT OF THE 70S FOR MOST AREAS EAST OF THE MOUNTAINS.
ON THU...A COLD FRONT IS STILL EXPECTED TO ARRIVE AND MOVE ACROSS
THE AREA DURING THE COURSE OF THE DAY. WIND FIELDS WILL BE IMPROVING
WITH 0-6KM BULK SHEAR INCREASING TO 35-40KT AND CAPES >2500J.
HENCE...SVR STORMS ARE CERTAINLY POSSIBLE PER THE SPC DAY 2 OUTLOOK.
LOOKS LIKE THE BEST THREAT FOR SEVERE STORMS WILL BE OVER THE
PIEDMONT IN THE MID TO LATE AFTERNOON HOURS. WINDS THROUGH THE
COLUMN WILL TAKE ON A DOWNSLOPE COMPONENT ON THU SO IT IS POSSIBLE
THAT COVERAGE ESPECIALLY ACROSS THE UPSTATE PERHAPS WILL NOT BE
100%. HENCE...POPS ARE HIGHEST ACROSS THE SOUTHERN PIEDMONT AREAS.
IT WILL BE ANOTHER HOT DAY ON THU WITH A MODEL BLEND PRODUCING HIGHS
IN THE 90-95 RANGE OUTSIDE THE MOUNTAINS AND MID 80S MOUNTAIN
VALLEYS.
&&
.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY/...
AS OF 130 PM EDT WEDNESDAY...EXPECT QUIET AND COOLER CONDITIONS FOR
THE SHORT TERM PERIOD. CONDITIONS QUICKLY DRY OUT THURSDAY EVENING
AS A SHARP UPPER TROUGH AXIS AND ASSOCIATED SURFACE COLD FRONT PUSH
EAST OF THE AREA. HOWEVER...SCATTERED LIGHT SHOWERS MAY CONTINUE
ACROSS THE NC MTNS THROUGH LATE THURSDAY NIGHT DUE TO INCREASING NW
UPSLOPE FLOW ALONG WITH THE PASSAGE OF WEAK UPPER DPVA THERE.
AN UPPER RIDGE OF H5 HIGH WILL REMAIN ANCHORED OVER THE SOUTHCENTRAL
STATES LEAVING OUR FORECAST AREA UNDER THE NW FLOW ALOFT FRI/SAT.
THIS WILL ALLOW CANADIAN SURFACE HIGH PRESSURE TO RIDGE SOUTH INTO
THE FORECAST AREA PROVIDING DRY NORTHERLY FLOW THROUGH THE PERIOD.
TEMPERATURES WILL BE AROUND 2-3 DEGREES BELOW NORMAL WITH HIGHS IN
THE LOWER TO MID 80S OVER THE PIEDMONT AND 70S IN THE HIGHER
TERRAIN.
&&
.LONG TERM /SATURDAY NIGHT THROUGH TUESDAY/...
AS OF 2PM WEDNESDAY...THE MODELS REMAIN IN FAIRLY GOOD AGREEMENT
THROUGH MOST OF THE PERIOD. AFTER A PREDOMINANTLY DRY WEEKEND...THE
RIDGE OVER THE EASTERN CONUS WILL BREAK DOWN BY THE BEGINNING OF
NEXT WEEK. A WEAK TROUGH WILL THEN SET UP OVER THE SOUTHEASTERN
CONUS AND ALLOW A MORE UNSETTLED SUMMERTIME PATTERN TO RETURN. THE
NEXT FRONTAL SYSTEM APPROACHES LATE MONDAY/EARLY TUESDAY...RESULTING
IN DIURNAL CHANCE POPS FOR THE ENTIRE CWA ON MONDAY. THE FRONT
PASSES AND STALLS OUT JUST TO THE SOUTH OF THE FORECAST AREA LATE
TUESDAY...SO CHANCE POPS CONTINUE FOR THE ENTIRE FORECAST AREA
THROUGH MIDWEEK. TEMPERATURES WILL REMAIN NEAR NORMAL THROUGH THE
EXTENDED PERIOD.
&&
.AVIATION /19Z WEDNESDAY THROUGH MONDAY/...
AT KCLT...VFR THROUGH THE FORECAST PERIOD. SPC MESOANAL PAGE STILL
SHOWS SOME CONVECTIVE INHIBITION. ALSO...CONVECTION ALLOWING MODELS
SHOWING DEEP CONVECTION DEVELOPING WELL WEST OF THE AIRFIELD CLOSER
TO THE WEAK FORCING ASSOCIATED WITH A MID LEVEL VORT. HENCE...HAVE
NOT INCLUDED ANY TSRA...BUT WILL MONITOR RADAR TRENDS CLOSELY. COLD
FRONT ON THU WILL AFFECT THE AREA IN THE AFTERNOON WITH A TIMEFRAME
AFTER THE VALID TIME OF THIS TAF. HOWEVER...SW WINDS WILL INCREASE
AHEAD OF THE FRONT PRIOR TO 18Z THU.
ELSEWHERE...MAIN QUESTION IS WHERE...IF ANY DEEP CONVECTION WILL
DEVELOP THIS AFTERNOON. LATEST HRRR AND HI-RES WRF INDICATE
CONVECTION DEVELOPING BY LATE AFTERNOON OVER THE WESTERN UPSTATE. AM
NOT CONFIDENT ENOUGH IN LOCATION TO ADD A TEMPO...BUT WILL ADD VCTS
TO THE KGMU...KGSP AND KAND TAFS. IT WILL THEN BE QUIET AND VFR
AFTER 00Z. A COLD FRONT WILL AFFECT THE AREA ON THU BUT AFTER
18Z. GUSTY SW WINDS WILL INCREASE AHEAD OF THE FRONT.
OUTLOOK...A COLD FRONT WILL BRING A GOOD CHANCE OF SHOWERS AND
THUNDERSTORMS TO THE REGION ON THURSDAY AFTERNOON WITH GUSTY WINDS
AND HAIL POSSIBLE.. HIGH PRESSURE WILL BUILD IN BEHIND THE FRONT AND
PRODUCE GENERALLY QUIET WEATHER AND VFR CONDITIONS THROUGH THE
WEEKEND.
CONFIDENCE TABLE...
18-24Z 00-06Z 06-12Z 12-18Z
KCLT HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KGSP HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAVL HIGH 100% HIGH 100% HIGH 95% HIGH 95%
KHKY HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KGMU HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAND HIGH 100% HIGH 100% HIGH 95% 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...VISIN
NEAR TERM...LG
SHORT TERM...JOH
LONG TERM...VISIN
AVIATION...LG
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
154 PM EDT WED JUN 12 2013
.SYNOPSIS...
WARM HIGH PRESSURE WILL BUILD ACROSS THE REGION TODAY...AHEAD OF AN
APPROACHING COLD FRONT...WHICH WILL CROSS THE AREA ON THURSDAY. DRY
HIGH PRESSURE WILL BUILD IN FROM THE NORTH FRIDAY THROUGH THE
WEEKEND. ANOTHER COLD FRONT WILL APPROACH THE REGION EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 145 PM...LOOKS LIKE CONVECTIVE INHIBITION HAS BEEN ERODED AWAY
PER SPC MESOANAL PAGE WITH OVER 3000J/KG OF SBCAPE NOW ACROSS THE
REGION. A BETTER CASE CAN NOW BE MADE FOR INCREASING THE CHC FOR
THUNDERSTORMS...ESPECIALLY IN LIGHT THAT SPC HAS NOW INCLUDED THE
AREA IN A SLIGHT RISK. LATEST HRRR AND HI-RES WRF DEVELOP SCT
CONVECTION MAINLY ACROSS THE WESTERN UPSTATE/NE GA CLOSER TO THE
WEAK LIFT PROVIDED BY A PASSING MID LEVEL VORT. HENCE...HAVE UPPED
POPS INTO THE SCT RANGE FROM ABOUT GREENVILLE WESTWARD. ANY STORMS
THAT DEVELOP HAVE THE POTENTIAL TO PRODUCE LOCALIZED DAMAGING WINDS
PER THE 900J OF DCAPE ANALYZED BY SPC.
AS OF 0955 AM...CURRENT RADAR TRENDS AND LATEST HRRR SUGGEST THAT WE
SHOULD BACK OFF ON THE IDEA THAT A CONVECTIVE COMPLEX WILL MOVE SE
ACROSS THE AREA OUT OF WV AND ACROSS THE FORECAST AREA THIS
AFTERNOON. PREVIOUS CONVECTION OVER WV HAS WANED AS IT MOVED SE INTO
A MORE STABLE AIRMASS. IN FACT...FORECAST SOUNDINGS AS MENTIONED
PREVIOUSLY LOOK CAPPED WITH CONSIDERABLE LOW LEVEL CIN. WILL HAVE
THE HIGHEST POPS OVER THE FAR EASTERN NC PIEDMONT WHERE SOME STORMS
CAN`T BE RULED OUT AND OVER THE FAR WEST...IN NE GA AND WESTERN
UPSTATE WHERE THE 06Z NAM HAD SOME QPF RESPONSE. ALSO ADJUSTED
TEMPS/DEWPOINTS/WINDS BASED ON LATEST TRENDS AND LAMP DATA. SOME
SOME LIGHT WIDELY SCATTERED LIGHT SHOWERS SHOWING UP ON RADAR ACROSS
THE WESTERN UPSTATE PROBABLY IN ASSOCIATION WITH A PASSAGE OF A MID
LEVEL VORT CENTER PER NAM/GFS. HAVE SOME WIDELY SCATTERED POPS EARLY
TO HANDLE THOSE.
PREVIOUS DISCUSSION:
AS OF 730 AM...CURRENT FORECAST TRENDS LOOK GOOD. MAIN FORECAST
PROBLEM IS WHETHER ANY SIGNIFICANT DEEP CONVECTION WILL OCCUR.
FORECAST SOUNDINGS LOOK CAPPED ALL DAY WITH CONSIDERABLE LOW LEVEL
CIN...BUT SOME CONVECTION ALLOWING MODELS LIKE THE EMC WRF AND
HI-RES WRF TAKE THE CURRENT CONVECTION OVER WV SE AND AND DEVELOP A
MCS WHICH PLOWS THROUGH THE AREA THIS AFTERNOON. HOWEVER...LATEST
HRRR AND LOCAL WRF ARE MUTED AND WEAKEN THE CONVECTION AS IT MOVES
SE INTO THE CURRENTLY MUCH LESS STABLE ENVIRONMENT AS DEPICTED BY
SPC MESOANAL PAGE. LOW END CHC POPS ARE CURRENTLY IN THE GRIDS AND
THAT LOOKS FINE FOR NOW. WILL EVALUATE TRENDS AND TRY TO FINE TUNE
FORECAST LATER THIS MORNING. A FEW LIGHT SHRA HAVE SHOWN UP ON RADAR
ACROSS THE NORTHERN UPSTATE FALLIGN OUT OF A MID LEVEL DECK. HAVFE
ADDED SOME WIDELY SCT POPS TO HANDLE THAT. EXPECT THOSE SHRA TO
DISSIPATE THIS MORNING.
PREVIOUS DISCUSSION...
FOR TODAY...A COUPLE OF INTERESTING THINGS TO DISCUSS. OVERALL...
THE WESTERN CAROLINAS WILL BE UNDER A NW FLOW ALOFT WITH THE
POTENTIAL FOR MESOSCALE VORT CENTERS TO MOVE DOWN ACROSS THE REGION.
WEAK HIGH PRESSURE AT THE SURFACE WILL NOSE IN FROM THE SOUTHWEST.
EXPECTED THE MAIN STORY TO BE THE HEAT...WITH GUIDANCE FOR THE LAST
SEVERAL DAYS SHOWING UPPER 90S E OF THE MTNS...OWING TO DOWNSLOPE
FLOW AND A STRONG CAPPING INVERSION. HOWEVER...QUICK DOWNWARD TREND
HAS DEVELOPED IN THE GUIDANCE...WHICH SEEMS REASONABLE GIVEN THE
AMOUNT OF MID AND HIGH LEVEL CONVECTIVE DEBRIS EXPECTED INTO THE MID
AFTERNOON. OUR FCST HIGHS ARE MUCH MORE IN LINE WITH A GUIDANCE
BLEND SO THERE IS LITTLE CHANGE FROM THE PREVIOUS FCST IN THAT
REGARD. PREVIOUS THOUGHTS WERE ALSO THAT DEEP CONVECTION WOULD BE
HIGHLY DISCOURAGED DUE TO A FORMIDABLE CAPPING INVERSION. THE NEW
GUIDANCE SUGGESTS THAT IT MIGHT NOT BE SO UNBREAKABLE LATE IN THE
AFTERNOON. SOME OF THE CONVECTION ALLOWING MODELS DEVELOP A
THUNDERSTORM COMPLEX OVER THE CENTRAL APPALACHIANS THIS AFTERNOON
THAT PLOWS SOUTHWARD ACROSS THE PIEDMONT OF THE CAROLINAS THROUGH
EARLY EVENING. IF THAT WERE TO HAPPEN...THERE WOULD BE ENOUGH
DOWNDRAFT CAPE FOR SEVERAL SWATHS OF WIND DAMAGE. THE GFS IS STILL
BASICALLY DRY AND CAPPED...BUT THE NAM SUGGESTS NUMEROUS STORMS. IT
SEEMS THE MOST LIKELY SCENARIO IS FOR STORM COVERAGE TO REMAIN
LIMITED BECAUSE OF THE CAP THAT MIGHT NOT BE OVERCOME UNTIL AFTER
21Z...BUT WARY OF ANY BLOWUP OF CONVECTION OVER SRN WV/SW VA...THAT
WOULD REQUIRE A QUICK OVERHAUL OF PRECIP CHANCES. THE CONVECTION IF
IT DEVELOPS WILL MOVE OFF TO THE S IN THE MID EVENING. THEN
ATTENTION TURNS TO THE NEXT POSSIBLE UPSTREAM MCS APPROACHING FROM
THE NW TOWARD DAYBREAK THURSDAY. AT THIS POINT...IT APPEARS THAT IT
WOULD NOT REACH THE MTNS BEFORE SUNRISE...SO THE POP WILL BE KEPT
LOW AT THE VERY END OF THE PERIOD.
&&
.SHORT TERM /THURSDAY THROUGH SATURDAY/...
AS OF 130 PM EDT WEDNESDAY...EXPECT QUIET AND COOLER CONDITIONS FOR
THE SHORT TERM PERIOD. CONDITIONS QUICKLY DRY OUT THURSDAY NIGHT AS
A SHARP UPPER TROUGH AXIS AND ASSOCIATED SURFACE COLD FRONT PUSH
EAST OF THE AREA. HOWEVER...LIGHT UPSLOPE SHOWERS CAN BE SEEN ALONG
THE TN BORDER THROUGH EARLY FRI MORNING DUE TO INCREASING LLVL NW
FLOW ALONG WITH THE PASSAGE OF WEAK UPPER DPVA THERE.
AN UPPER RIDGE OF H5 HIGH WILL REMAIN ANCHORED OVER THE SOUTHCENTRAL
STATES LEAVING OUR FORECAST AREA UNDER THE NW FLOW ALOFT FRI/SAT.
THIS WILL ALLOW CANADIAN SURFACE HIGH PRESSURE TO RIDGE SOUTH INTO
THE FORECAST AREA PROVIDING DRY NORTHERLY FLOW THROUGH THE PERIOD.
TEMPERATURES WILL BE AROUND 2-3 DEGREES BELOW NORMAL WITH HIGHS IN
THE LOWER TO MID 80S OVER THE PIEDMONT AND 70S IN THE HIGHER
TERRAIN.
&&
.LONG TERM /SATURDAY NIGHT THROUGH TUESDAY/...
AS OF 300 AM WEDNESDAY...MODELS IN GOOD AGREEMENT ON THE SRN CONUS
UPR RIDGE BREAKING DOWN SOMEWHAT BY THE END OF THE WEEKEND...WITH A
RETURN OF WLY UPR FLOW AND THE SHORTWAVE TRACK OVER THE CWFA FOR
EARLY NEXT WEEK. THE RIDGE WILL RE-ESTABLISH OVER THE SRN PLAINS BY
MIDWEEK...KEEPING THE ERN STATES IN PERSISTENT UPR TROFINESS. THIS
WILL LIKELY RESULT IN UNSETTLED WX RETURNING TO THE AREA FOR NEXT
WEEK...WITH SLIGHTLY ABOVE NORMAL TEMPS.
&&
.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
AT KCLT...VFR THROUGH THE FORECAST PERIOD. SPC MESOANAL PAGE STILL
SHOWS SOME CONVECTIVE INHIBITION. ALSO...CONVECTION ALLOWING MODELS
SHOWING DEEP CONVECTION DEVELOPING WELL WEST OF THE AIRFIELD CLOSER
TO THE WEAK FORCING ASSOCIATED WITH A MID LEVEL VORT. HENCE...HAVE
NOT INCLUDED ANY TSRA...BUT WILL MONITOR RADAR TRENDS CLOSELY. COLD
FRONT ON THU WILL AFFECT THE AREA IN THE AFTERNOON WITH A TIMEFRAME
AFTER THE VALID TIME OF THIS TAF. HOWEVER...SW WINDS WILL INCREASE
AHEAD OF THE FRONT PRIOR TO 18Z THU.
ELSEWHERE...MAIN QUESTION IS WHERE...IF ANY DEEP CONVECTION WILL
DEVELOP THIS AFTERNOON. LATEST HRRR AND HI-RES WRF INDICATE
CONVECTION DEVELOPING BY LATE AFTERNOON OVER THE WESTERN UPSTATE. AM
NOT CONFIDENT ENOUGH IN LOCATION TO ADD A TEMPO...BUT WILL ADD VCTS
TO THE KGMU...KGSP AND KAND TAFS. IT WILL THEN BE QUIET AND VFR
AFTER 00Z. A COLD FRONT WILL AFFECT THE AREA ON THU BUT AFTER
18Z. GUSTY SW WINDS WILL INCREASE AHEAD OF THE FRONT.
OUTLOOK...A COLD FRONT WILL BRING A GOOD CHANCE OF SHOWERS AND
THUNDERSTORMS TO THE REGION ON THURSDAY AFTERNOON WITH GUSTY WINDS
AND HAIL POSSIBLE.. HIGH PRESSURE WILL BUILD IN BEHIND THE FRONT AND
PRODUCE GENERALLY QUIET WEATHER AND VFR CONDITIONS THROUGH THE
WEEKEND.
CONFIDENCE TABLE...
18-24Z 00-06Z 06-12Z 12-18Z
KCLT HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KGSP HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAVL HIGH 100% HIGH 100% HIGH 95% HIGH 95%
KHKY HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KGMU HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAND HIGH 100% HIGH 100% HIGH 95% 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...ARK
NEAR TERM...LG
SHORT TERM...ARK
LONG TERM...ARK
AVIATION...PM
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NWS RAPID CITY SD
1007 AM MDT WED JUN 12 2013
.UPDATE...
ISSUED AT 947 AM MDT WED JUN 12 2013
BROAD AREA OF CLOUD COVER REMAINS OVER WESTERN SOUTH DAKOTA
SPREADING INTO NORTHEAST WYOMING ON BACK-SIDE OF DEPARTING LOW.
MODELS CONTINUE TO BE RELUCTANT IN DISSIPATING CLOUD COVER UNTIL
LATER THIS AFTERNOON. MORNING UPDATE HAD ADDRESSED THIS...ALONG
WITH TAPERING BACK HIGH TEMPS OVER THE PLAINS. HAVE ALSO DELAYED
CONVECTION CHANCES OVER NERN WY/BLKHLS AS INSTABILITY WILL REMAIN
WEAK UNTIL LATER IN THE DAY. UPDATES HAVE BEEN SENT.
&&
.SHORT TERM...TODAY THROUGH THURSDAY NIGHT
ISSUED AT 308 AM MDT WED JUN 12 2013
WATER VAPOR IMAGERY SHOWS A CUT OFF LOW ACROSS THE PACIFIC
NORTHWEST...AND WEAK RIDGING ACROSS THE NORTHERN HIGH PLAINS IN
THE WAKE OF THE SHORTWAVE NOW CROSSING EAST RIVER SD INTO
MINNESOTA. SURFACE ANALYSIS SHOWS HIGH PRESSURE FROM MONTANA TO
COLORADO.
HIGH PRESSURE WILL SLIDE INTO CENTRAL SOUTH DAKOTA TODAY BRINGING
QUIET WEATHER TO THE AREA FOR MUCH OF THE DAY TODAY. RETURN FLOW
WILL SET BACK UP FROM EASTERN MONTANA INTO NORTHEAST WYOMING AND
WESTERN SOUTH DAKOTA. TEMPERATURES IN THE 70S TO LOWER 80S ARE AGAIN
EXPECTED. UNSTABLE AIRMASS WILL REDEVELOP THIS AFTERNOON WITH MLCAPE
RANGING FROM 800 TO 1500 J/KG...AND WITH WEAKER CAPPING THAN
YESTERDAY. LOW LEVEL SHEAR WILL RAMP UP THROUGH THE LATE AFTERNOON
AND EVENING AS THE RETURN FLOW/LLJ STRENGTHENS. ISOLATED STORMS MAY
INITIATE OVER THE BLACK HILLS THIS AFTERNOON. OTHERWISE A SERIES OF
WAVES PUSHING INTO WESTERN WYOMING AND MONTANA WILL BRING
THUNDERSTORMS TOWARD THE BIG HORNS INTO CENTRAL MONTANA LATE THIS
AFTERNOON INTO TONIGHT. A DRYLINE WILL SET UP SOMEWHERE ACROSS
CENTRAL TO NORTHEASTERN WYOMING...AND THIS COULD BE THE FOCUS FOR
MORE CONVECTION. SUFFICIENT SHEAR WILL SUPPORT SUPERCELL DEVELOPMENT
LARGE HAIL AND DAMAGING WINDS POSSIBLE. THE BULK OF CONVECTION WILL
END BY 06Z...HOWEVER SOME LINGERING STORMS WILL BE POSSIBLE
OVERNIGHT WITHIN THE BAND OF THETA E ADVECTION AND LOW LEVEL JET
ACROSS WESTERN SOUTH DAKOTA.
STRENGTHENING ACTIVE SOUTHWEST FLOW ALOFT IS EXPECTED THURSDAY WITH
THE APPROACH OF THE NEXT TROUGH. SURFACE LOW WILL ALSO STRENGTHEN
NEAR THE MONTANA TO WYOMING BORDER LATE IN THE DAY ALONG A
BAROCLINIC ZONE. STRONG THETA E ADVECTION WILL CONTINUE ACROSS THE
CWA AHEAD OF THE SURFACE LOW. MOST LOCATIONS WILL SEE TEMPERATURES
REACH THE 80S AND DEWPOINTS REACHING THE UPPER 50S TO LOWER 60S. THE
SURFACE LOW WILL PUSH ACROSS EASTERN MONTANA THURSDAY AFTERNOON...AND
INTO THE DAKOTAS THURSDAY NIGHT. A SERIES OF UPPER WAVES WILL
COMBINE WITH A COLD FRONT CROSSING THE AREA TO BRING ANOTHER ROUND
OF THUNDERSTORMS. LOW LEVEL JET WILL CONTINUE ACROSS WESTERN SOUTH
DAKOTA...WHICH WILL AGAIN RESULT IN ENOUGH SHEAR FOR SUPERCELL
DEVELOPMENT. LARGE HAIL AND DAMAGING WINDS WILL BE THE MAIN THREATS
THURSDAY. CONVECTION WILL PUSH NORTHEASTWARD OVERNIGHT...CLEARING
THE CWA LATE THURSDAY NIGHT.
&&
.LONG TERM...FRIDAY THROUGH TUESDAY
ISSUED AT 308 AM MDT WED JUN 12 2013
MEAN WESTERN CONUS TROUGHING WILL CONTINUE IN THE
PERIOD...WITH TEMPORARY WESTERN TROUGH REMOVAL FRI-SUN PER TROUGH
KICKING BY AN ADVANCING NORTHERN PAC UPPER TROUGH. RETAINED LOW CHANCES
FOR POPS FRI OVER NE WY AND FAR SE FA GIVEN WITH THE ADVECTION OF
THE MAIN UPPER TROUGH INTO SOUTHERN CANADA. THIS UPPER TROUGH WILL
FRACTURE OVER SOUTHERN MB/SK WITH THE REMAINING VORT LOBE SHIFTING
SE SUN. MEAN RIDGING FAVORED EARLY NEXT WEEK AHEAD OF RE-INITIATED
WESTERN CONUS TROUGHING...SUPPORTING A WARMING TREND WITH INCREASING
CHANCES FOR SHRA/TS AS WEAK DISTURBANCES ADVECT EAST OUT OF THE MEAN
WESTERN CONUS TROUGH. BEST CHANCES FOR ANY PRECIP LOOKS TO REMAIN
OVER NE WY AND SOUTHERN PORTIONS OF THE FA...GIVEN HIGH TERRAIN
INITIATION AND LL THETA-E RIDGING. KEPT POPS FAIRLY LOW GIVEN
CONCERNS ON IMPULSE STRENGTH/TRACK/AND LL MOISTURE RECOVERY.
NOT MUCH CHANGES TO PREVIOUS POP NUMBERS...RETAINING LOW NUMBERS
IN MOST PERIODS. MONDAY COULD END UP DRY MOST PLACES...ESP IF
RIDGING IS DELAYED. OTHERWISE...A TRANSITION TO SW FLOW EARLY NEXT
WEEK SUPPORTS A SMALL UPTICK IN POPS. GENERALLY NORMAL TEMPS
EXPECTED IN THE PERIOD. DEGREE OF CAA BEHIND SUNDAY/S WAVE STILL
WAVERING IN GFS/ECMWF SOLUTIONS WITH POTENTIALLY COOLER NUMBERS
POSSIBLE. HAVE SIDED SLIGHTLY BELOW NORMAL FOR MONDAY ATTM.
OTHERWISE...WARMING TREND LIKELY BEYOND MONDAY GIVEN EASTERN
TRANSLATION OF THE NEXT RIDGE.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 509 AM MDT WED JUN 12 2013
IFR/LIFR CIGS WILL BE FOUND FROM NE WY NEAR W43...SE TO RAP AND IN
SURROUNDING AREAS NEAR THE BH. FLOW WILL VEER EASTERLY WHICH MAY
ALLOW CIGS TO PERSIST INTO EARLY AFTERNOON ALONG THE EASTERN BH
FOOTHILLS INCLUDING RAP. OTHERWISE...VFR CONDITIONS ARE EXPECTED
ACROSS THE REMAINDER OF THE REGION AS WEAK SFC HIGH PRESSURE
SHIFTS SOUTHEAST ACROSS THE CENTRAL DAKOTAS. ANOTHER MID LEVEL
IMPULSE IN SW FLOW MAY SUPPORT AN ISOLD TS LATE THIS AFTERNOON AND
OVERNIGHT FROM NE WY INTO NW SD.
&&
.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...NONE.
&&
$$
UPDATE...77
SHORT TERM...13
LONG TERM...JC
AVIATION...JC
AREA FORECAST DISCUSSION
NWS CORPUS CHRISTI TX
241 PM CDT WED JUN 12 2013
.SHORT TERM (TONIGHT THROUGH THURSDAY NIGHT)...MODELS STILL SHOW
LOTS OF AVAILABLE MOISTURE THROUGH THURSDAY NIGHT (PWATS AROUND 2
INCHES)...ALTHOUGH THE IMPACTS FROM THE UPPER LOW BEGIN TO SHIFT
TO THE NORTHWEST AND OUT OF THE CWFA. AS A RESULT...POP FORECAST
WILL REFLECT HIGHER POPS OUT TO THE WEST FOR THE AFTERNOON AND
EVENING PERIODS THROUGH THURSDAY NIGHT. POP GUIDANCE FROM MODELS
(ESPECIALLY ECMWF) LIKELY A BIT TOO HIGH AS GUIDANCE IS PROBABLY
KEYING ON THE VERY HIGH RH VALUES (WHICH ARE VERY HIGH FOR THE
AREA AT THIS TIME OF YEAR). FOR THIS EVENING...WILL JUST GO WITH
SLIGHT CHANCE POPS WESTERN AREAS (ECHOES SHOWING UP NOW ALBEIT
WEAK ONES AND MAY NOT LAST)...WITH RAIN CHANCES SHIFTING TOWARD
THE WATERS AND COAST OVERNIGHT TONIGHT. HRRR 4KM MODEL IS SHOWING
ANY ACTIVITY IN OUR CWFA THIS EVENING OUT BY 02Z (IF NOT EARLIER).
ONE MORE DAY OF ISOLATED TO SCATTERED CONVECTION EASTERN AREAS
ON THURSDAY...WITH BETTER CHANCES FOR CONVECTION FARTHER WEST MORE
PROXIMATE TO UPPER LOW. FOR THURSDAY NIGHT...WILL GO WITH LOW END
CHANCE POPS ALONG THE RIO GRANDE...WITH SLIGHT CHANCE REMAINDER
OF WESTERN FOUR COUNTIES. WITH MOISTURE VALUES SO HIGH AND
REMAINING SO FOR THE NEXT THREE PERIODS...SAW NO NEED TO SWAY TOO
MUCH FROM A PERSISTENCE FORECAST AT THIS TIME...ALTHOUGH DID GO A
BIT WARMER THURSDAY NIGHT THAN TONIGHT OUT WEST WHERE MOISTURE AND
CLOUDS WILL LINGER THE LONGEST.
&&
.MARINE (TONIGHT THROUGH THURSDAY NIGHT)...EXPECTING RAINFALL
ACTIVITY IN THE WATERS TO PICK UP SOME AFTER MIDNIGHT...WITH
ISOLATED TO SCATTERED SHOWERS/POSSIBLE THUNDERSTORMS BY SUNRISE.
ACTIVITY SHOULD DECREASE/DIMINISH THURSDAY AFTERNOON...WITH
COVERAGE EVEN LOWER THURSDAY NIGHT (AND MAINLY SOUTH) AS THE
MOISTURE AXIS BEGINS TO SHIFT NORTHWEST.
&&
.LONG TERM (FRIDAY THROUGH WEDNESDAY)...EXTENDED PERIOD BEGINS WITH
UNSETTLED WEATHER GRADUALLY ENDING AS A SLOW MOVING UPPER LOW
FINALLY BEGINS TO ROTATE NORTH OF THE AREA. PWATS REMAIN HIGH INTO
THE EVENING ON FRIDAY BUT WITH UPPER SUPPORT LEAVING AND A BUILDING
GULF RIDGE BRINGING DRIER AIR OVER THE EAST WILL CONFINE POPS TO THE
WESTERN COUNTIES.
UPPER RIDGE WILL CONTINUE TO BROADEN AND EXPAND OVER THE WEEKEND AND
EARLY NEXT WEEK IN RESPONSE TO AN UPPER LOW DROPPING INTO THE
PACIFIC NORTHWEST. EXPECT CONDITIONS TYPICAL OF SUMMERTIME RIDGES
WITH TEMPERATURES SLIGHTLY ABOVE NORMAL AND HEAT INDICES COMMONLY
BETWEEN 105 AND 109 IN THE AFTERNOONS.
&&
.PRELIMINARY POINT TEMPS/POPS...
CORPUS CHRISTI 80 95 80 96 76 / 20 30 10 10 10
VICTORIA 75 93 75 94 75 / 10 20 10 10 10
LAREDO 76 95 77 100 80 / 20 40 30 20 20
ALICE 75 94 76 98 76 / 10 30 10 10 10
ROCKPORT 80 91 80 92 78 / 10 30 10 10 10
COTULLA 74 94 75 94 76 / 20 30 20 20 20
KINGSVILLE 78 95 78 97 76 / 20 30 10 10 10
NAVY CORPUS 79 91 80 92 79 / 20 30 10 10 10
&&
.CRP WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
GW/86...SHORT TERM
JV/71...LONG TERM
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
401 PM EDT WED JUN 12 2013
.SYNOPSIS...
WEAK UPPER LEVEL DISTURBANCES FROM THE OHIO VALLEY WILL BRING A
CHANCE FOR THUNDERSTORMS TO THE MOUNTAINS LATE THIS AFTERNOON. A
LEE SIDE TROUGH WILL BRING A SLIGHT CHANCE FOR THUNDERSTORMS FOR
AREAS EAST OF THE BLUE RIDGE THIS EVENING. A STRONG COLD FRONT
WILL SWEEP ACROSS THE REGION TOMORROW. STRONG TO SEVERE STORMS
WILL ACCOMPANY THE FRONT.
&&
.NEAR TERM /THROUGH THURSDAY/...
AS OF 356 PM EDT WEDNESDAY...
A FEW REMNANT STORMS ENTERED THE MOUNTAINS FROM THE OHIO RIVER
VALLEY THIS MORNING AND EARLY AFTERNOON. THESE STORMS FELL APART
MOVING TOWARD THE BLUE RIDGE. THE 06/12 18Z HRRR HAS THE BEST HANDLE
ON CONVECTION LATE THIS AFTERNOON WITH BEST CHANCE SOUTH OF A LINE
FROM BLUEFIELD WV TO MOUNT AIRY NC. THESE SHOWERS SHOULD FADE WITH
LOSE OF HEATING.
THE FOCUS OVERNIGHT INTO TOMORROW WILL BE A FAST MOVING COLD FRONT.
THIS FRONT HAS GOOD DYNAMIC AND MOISTURE TO WORK WITH AND WILL
LIKELY BRING SEVERE WEATHER INTO THE REGION. THE MAIN THREAT WITH
THIS FRONT WILL BE STRAIGHT LINE WINDS. SOME METEOROLOGIST ARE
COMPARING THIS FRONT TO THE DERECHO OF JUNE 2012. THERE ARE SEVERAL
DIFFERENCES BETWEEN THE TWO. THE MAIN DIFFERENCE IS THAT THIS FRONT
WILL BE ENTERING THE AREA DURING THE MORNING THEN JUMPING TO A LEE
TROUGH IN THE EAST BY EARLY AFTERNOON. THUNDERSTORMS LIKE TO FEED
OFF OF HEAT WHICH IS LACKING IN THE MORNING. THE FRONT MAY NOT JUMP
TO THE LEE TROUGH UNTIL THE AFTERNOON WHICH WILL ALLOW THE SW VA
PIEDMONT...SOUTHSIDE VA...AND NORTHERN NC PIEDMONT TO WARM INTO THE
LOWER 90S. THIS AREA WILL HAVE THE GREAT POTENTIALLY FOR BLACKSBURG
CWA TO HAVE SEVERE WEATHER. LAST YEAR`S DERECHO MOVED INTO A VERY
WARM ENVIRONMENT OF 90F TO 105F LATE IN THE AFTERNOON/EARLY EVENING.
ALSO WITH THIS FRONT...A WEST WIND WILL BE ESTABLISHED EARLY.
SHOWERS AND THUNDERSTORMS WILL MOVING INTO THE MOUNTAINS AND
POSSIBLY FADE TOWARD THE BLUE RIDGE DURING THE MORNING. AS THE FRONT
JUMPS TO THE LEE TROUGH...A LINE OF CONVECTION WILL DEVELOP OVER THE
PIEDMONT. THIS SYSTEM SHOULD EXIT THE AREA BY RUSH HOUR TOMORROW
EVENING.
&&
.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY NIGHT/...
AS OF 230 PM EDT WEDNESDAY...
GOING TO SEE SHOWERS AND STORMS EXITING THE EASTERN CWA BY THURSDAY
EVENING WITH LINGERING SHOWERS ACROSS THE WESTERN SLOPES AS ANOTHER
PIECE OF SHORTWAVE ENERGY FOLLOWS THE MAIN FRONT. THINK THE
SUBSIDENCE BEHIND THE CONVECTION TO WORK IN DRIER AIR AND CLEAR
SKIES OUT BY LATE THURSDAY NIGHT IN MOST OF THE REGION...LINGERING
CLOUDS ACROSS THE WESTERN SLOPES OF SE WV.
THERE IS YET ANOTHER SHORTWAVE PUSHING SOUTHEAST ACROSS THE MTNS
FRIDAY ALTHOUGH MOISTURE APPEARS LIMITED. CANNOT RULE OUT A FEW
SPRINKLES OR LIGHT RAIN SHOWERS IN THE MTNS OF SE WV/ALLEGHANY
HIGHLANDS OF VA.
THE AIRMASS WILL BE DRIER FOR PERIOD OF 48 HOURS WHILE SFC HIGH
BUILDS OVERHEAD BY SATURDAY. TEMPS WILL BE A FEW DEGREES COOLER THAN
NORMAL FRIDAY WITH HIGHS RANGING FROM THE LOWER 70S WEST TO LOWER
80S EAST...FOLLOWED BY LOWS FRIDAY NIGHT FROM AROUND 50 WEST TO MID
50S EAST.
THERE SHOULD BE ENOUGH GRADIENT THU NIGH-FRIDAY FOR SOME BREEZY
CONDITIONS...GUSTS UP TO 25 MPH.
SATURDAY WILL BE DRY AND SEASONAL WITH HIGHS RANGING FROM THE MID TO
UPPER 70S WEST TO LOWER TO MID 80S EAST.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
AS OF 115 PM EDT WEDNESDAY...
EXPECT ANOTHER ACTIVE PERIOD AT LEAST FOR SUNDAY NIGHT-TUESDAY AS
ANOTHER FRONT MAKES ITS WAY TOWARD AND THROUGH THE AREA.
SUNDAY...LOOKING AT HIGH PRESSURE MOVING OFFSHORE SETTING OUR AREA
UP IN THE RETURN FLOW AND INCREASED HUMIDITY. SUNDAY WILL BE A DAY
OF TYPICAL SHOWER/STORM DEVELOPMENT IN THE MTNS.
AS WE HEAD INTO MONDAY-TUESDAY...FRONTAL SYSTEM MOVES FROM GREAT
LAKES-CENTRAL PLAINS SOUTHEAST INTO THE MID ATLANTIC SOUTHWEST TO
THE LOWER OHIO VALLEY. MODELS SIMILAR OVERALL BUT TIMING INDIVIDUAL
CLUSTERS OF SHORTWAVES WILL BE PROBLEMATIC. STILL LOOKS LIKE AN
ACTIVE PATTERN WHERE 2-3 ROUNDS OF SHOWERS/STORMS WILL MOVE ACROSS.
FRONT APPEARS TO FINALLY INCH SOUTHEAST OF OUR AREA BY WEDNESDAY
WITH DRIER AIR MOVING IN FOR AT LEAST ONE OR TWO DAYS.
&&
.AVIATION /20Z WEDNESDAY THROUGH MONDAY/...
AS OF 140 PM EDT WEDNESDAY...
SCATTERED THUNDERSTORMS WERE MOVING SOUTHEAST ACROSS SOUTHEAST
WEST VIRGINIA AND SOUTHWEST VIRGINIA EARLY THIS AFTERNOON. HAVE
ADDED THUNDERSTORMS IN THROUGH 20Z FOR THE BLF TAF. SEEING SOME
DEVELOPMENT STILL TO THE NORTHWEST SO OCCURRENCE OF THUNDER MAY
NEED TO BE PROLONGED AT BLF AND ADDED TO LWB LATER THIS AFTERNOON
INTO EARLY EVENING. OTHERWISE EXPECT ISOLATED TO SCATTERED SHOWERS
AND THUNDERSTORMS IN THE LEE OF THE APPALACHIANS LATE THIS
AFTERNOON AND EVENING. AT THIS TIME THE CHANCE IS LOW ENOUGH TO
KEEP OUT OF THE TAFS.
A FRONT WILL BRING A PERIOD OF SUB-VFR CONDITIONS TO THE AREA
LATE TONIGHT AND THURSDAY MORNING...ASSOCIATED WITH AN ORGANIZED
AREA OF SHOWERS/THUNDERSTORMS. STRONG GUSTY WINDS ARE POSSIBLE
WITH THE THUNDERSTORMS...ESPECIALLY AT DAN AND LYH THURSDAY
AFTERNOON.
HIGH PRESSURE WILL BUILD IN FRIDAY AND SATURDAY RESULTING IN VFR
WEATHER. COULD SEE FOG AT THE TYPICAL LOCATIONS SUNDAY MORNING...
LWB/BCB...OTHERWISE VFR. SEEING RETURN FLOW OFF THE ATLANTIC
SUNDAY WITH A FRONT MOVING INTO THE MIDWEST/GREAT LAKES. A 20
PERCENT CHANCE OF THUNDERSTORMS SUNDAY AFTERNOON IN THE AREA AS
WELL.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...RCS
NEAR TERM...RCS
SHORT TERM...WP
LONG TERM...WP
AVIATION...AMS/RCS
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
530 PM CDT WED JUN 12 2013
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 314 PM CDT WED JUN 12 2013
AT 3 PM...WATER VAPOR IMAGERY AND VAD WIND PROFILERS SHOW A
STRONG NEGATIVELY TITLED TROUGH MOVING EAST OUT OF EASTERN SOUTH
DAKOTA. THE RAP HAS AN ANOMALOUSLY STRONG PV ANOMALY EXTENDING
DOWN TO 500 MB. A 850 MB TROUGH IS CURRENTLY MOVING THROUGH THE
WESTERN PORTIONS OF THE FORECAST AREA. MEANWHILE A 700 MB TROUGH
WAS LOCATED ACROSS NORTHWEST IOWA AND SOUTHWEST MINNESOTA. A FEW
SHOWERS HAVE DEVELOPED ACROSS NORTHEAST IOWA AND NEAR LA CROSSE.
MEANWHILE FURTHER TO THE NORTH...A BAND OF SHOWERS AND
THUNDERSTORMS IN AN AREA OF MODERATE TO STRONG 900 TO 700 MB
FRONTOGENESIS.
BOTH THE RAP AND GFS SHOW THAT THE VERY STRONG PV ANOMALY WILL
MOVE EAST SOUTHEAST THROUGH THE FORECAST AREA LATE THIS AFTERNOON
AND EARLY THIS EVENING. AS IT APPROACHES...WE EXPECT TO RAPID
ASCENT TAKE PLACE ACROSS THE AREA WITHIN THE NEXT 2 HOURS. THE
LAPS IS SHOWING A LOW OVER EAST-CENTRAL IOWA. HOWEVER LOOKING AT
THE WIND FIELDS AND THE APPROACHING PV ANOMALY EXPECT THAT THE
ACTUAL LOW OVER NORTH-CENTRAL IOWA WILL BECOME THE PRIMARY SURFACE
LOW. WITH THIS IN MIND...EXPECT THE WARM FRONT TO POTENTIALLY LIFT
A BIT FURTHER NORTH THIS AFTERNOON. POSSIBLY AS FAR NORTH AS THE
INTERSTATE 90 CORRIDOR. REGARDLESS OF THE SURFACE LOW...THE 0-6KM
SHEAR IS FAVORABLE FOR THE DEVELOPMENT OF RIGHT-MOVING SUPERCELLS
ALONG AND SOUTH OF THE INTERSTATE 90 CORRIDOR. THE 0-1 KM HELICITY
IS FAVORABLE ALONG THE WARM FRONT FOR THE DEVELOPMENT OF STRONG
TORNADOES ESPECIALLY ACROSS FAYETTE AND CLAYTON COUNTIES IN
NORTHEAST IOWA AND GRANT COUNTY IN SOUTHWEST WISCONSIN. THE HRRR
CONTINUES TO GENERATE QUITE A FEW SUPERCELLS ALONG AND SOUTH OF
INTERSTATE 90 BETWEEN 12.19Z AND 13.02Z. ALSO EXPECT TO SEE LARGE
HAIL /DUE TO THE FAT CAPE/...DAMAGING WINDS /DCAPES OVER
1000 J/KG/...AND VERY EFFICIENT RAIN PRODUCERS /1.8 PRECIPITABLE
WATER AND WARM CLOUD DEPTHS OVER 4 KM/.
AS THE COLD POOLS EVOLVE LATE THIS AFTERNOON AND EARLY EVENING...
EXPECT A LINE OF STORMS WILL DEVELOP SOMEWHERE ALONG AND EAST OF
THE MISSISSIPPI RIVER. THIS LINE WILL THEN MOVE QUICKLY EAST AS A
DERECHO THROUGH SOUTHERN WISCONSIN...NORTHERN ILLINOIS...
INDIANA...OHIO...AND POSSIBLY SOUTHWEST LOWER MICHIGAN.
IN THE WAKE OF THIS PV ANOMALY...EXPECT HIGH PRESSURE TO QUICKLY
BUILD ACROSS THE AREA. THIS WILL PROVIDE DRY WEATHER FOR LATE
TONIGHT AND THURSDAY. HIGH TEMPERATURES ON THURSDAY WILL BE IN THE
LOWER AND MID 70S.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 314 PM CDT WED JUN 12 2013
ON FRIDAY AFTERNOON AND NIGHT...THE 850 MB MOISTURE TRANSPORT WILL
RAPIDLY INCREASE ACROSS THE FORECAST AREA AS A SHORTWAVE TROUGH
ROUNDS THE UPPER LEVEL RIDGE. THE LOW LEVEL JET WILL BRING 1 TO
2K J/KG MU CAPE INTO THE FORECAST AREA. WHILE THE 0-6 KM SHEAR IS
NOT SUFFICIENT FOR SUPERCELLS...THE 0-3 KM SHEAR DOES SUGGEST THE
POTENTIAL FOR SOME ISOLATED AREAS OF DAMAGING WINDS. WITH WARM
CLOUD LAYER DEPTHS ABOVE 4 KM AND PRECIPITABLE WATER VALUES UP TO
1.6 INCHES...THE STORMS WILL HIGHLY EFFICIENT AT PRODUCING RAIN...
THUS...WILL HAVE TO WATCH OUT FOR THE POTENTIAL FOR SOME
LOCALIZED FLOODING ON FRIDAY NIGHT.
ON SATURDAY NIGHT AND SUNDAY...THE MODELS SHOW THAT A MESOSCALE
CONVECTIVE COMPLEX WILL DEVELOP OVER SOUTH DAKOTA AND NEBRASKA.
THIS SYSTEM LOOKS LIKE IT WILL TRACK WILL MAINLY AFFECT AREAS
SOUTH OF THE INTERSTATE 90 CORRIDOR. WITH THE 0-6KM SHEAR LESS
THAN 40 KNOTS...NOT EXPECTING ANY SEVERE WEATHER AT THIS TIME.
BEYOND THIS TIME PERIOD...THE MODELS CONTINUE TO STRUGGLE WITH THE
TIMING AND POSITION SHORT WAVE TROUGHS THROUGH THE REGION...THUS
JUST STAYED WITH THE ALL BLEND.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 530 PM CDT WED JUN 12 2013
INSTABILITY AND A GOOD MOISTURE FEED WILL FUEL SHOWERS AND STORMS AS
A SHORTWAVE TROUGH DROPS SOUTHEAST ACROSS THE REGION EARLY THIS
EVENING. MANY OF THESE HAVE BEEN STRONG TO SEVERE...BUT THIS
ACTIVITY WAS SOUTH OF KRST/KLSE. EXPECTING THE BULK OF THE
SHRA/TS TO BE SOUTH OF KRST/KLSE BY 02Z OR SO. HIGH PRESSURE
THEN BUILDS IN...CLEARING THE SKIES OVERNIGHT. BUFKIT SOUNDINGS
SUGGEST AFTERNOON CU DEVELOPMENT FOR THU...BUT CONDITIONS SHOULD
STAY VFR - AFTER THE SHRA/TS EXIT SOUTHEAST EARLY THIS EVENING.
&&
.HYDROLOGY...
ISSUED AT 314 PM CDT WED JUN 12 2013
WITH HIGH PRECIPITABLE WATER VALUES AND WARM CLOUD LAYER DEPTHS
ABOVE 4 KM...THE STORMS THIS AFTERNOON AND EVENING AND ON FRIDAY
NIGHT WILL VERY EFFICIENT RAIN PRODUCERS. AS A RESULT...THERE IS
SOME CONCERN THAT THERE COULD BE SOME LOCALIZED FLASH FLOODING.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...BOYNE
LONG TERM....BOYNE
AVIATION.....RIECK
HYDROLOGY....BOYNE
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
315 PM CDT WED JUN 12 2013
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 314 PM CDT WED JUN 12 2013
AT 3 PM...WATER VAPOR IMAGERY AND VAD WIND PROFILERS SHOW A
STRONG NEGATIVELY TITLED TROUGH MOVING EAST OUT OF EASTERN SOUTH
DAKOTA. THE RAP HAS AN ANOMALOUSLY STRONG PV ANOMALLY EXTENDING
DOWN TO 500 MB. A 850 MB TROUGH IS CURRENTLY MOVING THROUGH THE
WESTERN PORTIONS OF THE FORECAST AREA. MEANWHILE A 700 MB TROUGH
WAS LOCATED ACROSS NORTHWEST IOWA AND SOUTHWEST MINNESOTA. A FEW
SHOWERS HAVE DEVELOPED ACROSS NORTHEAST IOWA AND NEAR LA CROSSE.
MEANWHILE FURTHER TO THE NORTH...A BAND OF SHOWERS AND
THUNDERSTORMS IN AN AREA OF MODERATE TO STRONG 900 TO 700 MB
FRONTOGENESIS.
BOTH THE RAP AND GFS SHOW THAT THE VERY STRONG PV ANOMALY WILL
MOVE EAST SOUTHEAST THROUGH THE FORECAST AREA LATE THIS AFTERNOON
AND EARLY THIS EVENING. AS IT APPROACHES...WE EXPECT TO RAPID
ASCENT TAKE PLACE ACROSS THE AREA WITHIN THE NEXT 2 HOURS. THE
LAPS IS SHOWING A LOW OVER EAST-CENTRAL IOWA. HOWEVER LOOKING AT
THE WIND FIELDS AND THE APPROACHING PV ANOMALY EXPECT THAT THE
ACTUAL LOW OVER NORTH-CENTRAL IOWA WILL BECOME THE PRIMARY SURFACE
LOW. WITH THIS IN MIND...EXPECT THE WARM FRONT TO POTENTIALLY LIFT
A BIT FURTHER NORTH THIS AFTERNOON. POSSIBLY AS FAR NORTH AS THE
INTERSTATE 90 CORRIDOR. REGARDLESS OF THE SURFACE LOW...THE 0-6KM
SHEAR IS FAVORABLE FOR THE DEVELOPMENT OF RIGHT-MOVING SUPERCELLS
ALONG AND SOUTH OF THE INTERSTATE 90 CORRIDOR. THE 0-1 KM HELICITY
IS FAVORABLE ALONG THE WARM FRONT FOR THE DEVELOPMENT OF STRONG
TORNADOES ESPECIALLY ACROSS FAYETTE AND CLAYTON COUNTIES IN
NORTHEAST IOWA AND GRANT COUNTY IN SOUTHWEST WISCONSIN. THE HRRR
CONTINUES TO GENERATE QUITE A FEW SUPERCELLS ALONG AND SOUTH OF
INTERSTATE 90 BETWEEN 12.19Z AND 13.02Z. ALSO EXPECT TO SEE LARGE
HAIL /DUE TO THE FAT CAPE/...DAMAGING WINDS /DCAPES OVER
1000 J/KG/...AND VERY EFFICIENT RAIN PRODUCERS /1.8 PRECIPITABLE
WATER AND WARM CLOUD DEPTHS OVER 4 KM/.
AS THE COLD POOLS EVOLVE LATE THIS AFTERNOON AND EARLY EVENING...
EXPECT A LINE OF STORMS WILL DEVELOP SOMEWHERE ALONG AND EAST OF
THE MISSISSIPPI RIVER. THIS LINE WILL THEN MOVE QUICKLY EAST AS A
DERECHO THROUGH SOUTHERN WISCONSIN...NORTHERN ILLINOIS...
INDIANA...OHIO...AND POSSIBLY SOUTHWEST LOWER MICHIGAN.
IN THE WAKE OF THIS PV ANOMALY...EXPECT HIGH PRESSURE TO QUICKLY
BUILD ACROSS THE AREA. THIS WILL PROVIDE DRY WEATHER FOR LATE
TONIGHT AND THURSDAY. HIGH TEMPERATURES ON THURSDAY WILL BE IN THE
LOWER AND MID 70S.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 314 PM CDT WED JUN 12 2013
ON FRIDAY AFTERNOON AND NIGHT...THE 850 MB MOISTURE TRANSPORT WILL
RAPIDLY INCREASE ACROSS THE FORECAST AREA AS A SHORTWAVE TROUGH
ROUNDS THE UPPER LEVEL RIDGE. THE LOW LEVEL JET WILL BRING 1 TO
2K J/KG MU CAPE INTO THE FORECAST AREA. WHILE THE 0-6 KM SHEAR IS
NOT SUFFICIENT FOR SUPERCELLS...THE 0-3 KM SHEAR DOES SUGGEST THE
POTENTIAL FOR SOME ISOLATED AREAS OF DAMAGING WINDS. WITH WARM
CLOUD LAYER DEPTHS ABOVE 4 KM AND PRECIPITABLE WATER VALUES UP TO
1.6 INCHES...THE STORMS WILL HIGHLY EFFICIENT AT PRODUCING RAIN...
THUS...WILL HAVE TO WATCH OUT FOR THE POTENTIAL FOR SOME
LOCALIZED FLOODING ON FRIDAY NIGHT.
ON SATURDAY NIGHT AND SUNDAY...THE MODELS SHOW THAT A MESOSCALE
CONVECTIVE COMPLEX WILL DEVELOP OVER SOUTH DAKOTA AND NEBRASKA.
THIS SYSTEM LOOKS LIKE IT WILL TRACK WILL MAINLY AFFECT AREAS
SOUTH OF THE INTERSTATE 90 CORRIDOR. WITH THE 0-6KM SHEAR LESS
THAN 40 KNOTS...NOT EXPECTING ANY SEVERE WEATHER AT THIS TIME.
BEYOND THIS TIME PERIOD...THE MODELS CONTINUE TO STRUGGLE WITH THE
TIMING AND POSITION SHORT WAVE TROUGHS THROUGH THE REGION...THUS
JUST STAYED WITH THE ALL BLEND.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1214 PM CDT WED JUN 12 2013
A VIGOROUS UPPER LEVEL DISTURBANCE WILL BRING SHOWERS AND
THUNDERSTORMS TO THE TAF SITES THIS AFTERNOON INTO EARLY THIS
EVENING. A FEW STORMS COULD BECOME SEVERE WITH LARGE
HAIL...DAMAGING WINDS. AN ISOLATED TORNADO IS ALSO POSSIBLE BUT
THE HIGHER CHANCES WILL BE ACROSS NORTHEAST IOWA AND FAR SOUTHWEST
WISCONSIN. MVFR TO IFR CONDITIONS ARE POSSIBLE IN THE
THUNDERSTORMS THIS AFTERNOON. A COLD FRONT WILL PUSH ACROSS THE
AREA THIS EVENING WITH WINDS SWITCHING TO THE NORTHWEST. AFTER A
BRIEF PERIOD OF MVFR STRATUS RIGHT BEHIND THE FRONT...VFR
CONDITIONS ARE EXPECTED LATE TONIGHT INTO THURSDAY MORNING.
&&
.HYDROLOGY...
ISSUED AT 314 PM CDT WED JUN 12 2013
WITH HIGH PRECIPITABLE WATER VALUES AND WARM CLOUD LAYER DEPTHS
ABOVE 4 KM...THE STORMS THIS AFTERNOON AND EVENING AND ON FRIDAY
NIGHT WILL VERY EFFICIENT RAIN PRODUCERS. AS A RESULT...THERE IS
SOME CONCERN THAT THERE COULD BE SOME LOCALIZED FLASH FLOODING.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...BOYNE
LONG TERM...BOYNE
AVIATION...WETENKAMP
HYDROLOGY...BOYNE
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1214 PM CDT WED JUN 12 2013
.UPDATE...
ISSUED AT 1214 PM CDT WED JUN 12 2013
INCREASING THREAT FOR SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE
FORECAST AREA THIS AFTERNOON. THE HIGHEST CHANCES FOR SEVERE
THUNDERSTORMS WILL BE ALONG AND SOUTH OF THE INTERSTATE 94 CORRIDOR.
DAMAGING WINDS...LARGE HAIL...AND A FEW TORNADOES ARE POSSIBLE
THIS AFTERNOON...ESPECIALLY ACROSS NORTHEAST IOWA INTO FAR
SOUTHWEST WISCONSIN. FAYETTE...CLAYTON...AND GRANT COUNTIES HAVE
THE HIGHEST CHANCES OF SEEING A TORNADO THIS AFTERNOON. A LARGE
TORNADO OR TWO IS POSSIBLE...ESPECIALLY NORTHEAST OF THE SURFACE
LOW.
AT THIS TIME...A POTENT SHORTWAVE WAS DRIVING SOUTHEAST ACROSS
EASTERN SOUTH DAKOTA/SOUTHWEST MINNESOTA AND LOOKED RATHER
IMPRESSIVE ON WATER VAPOR. MEANWHILE...SURFACE LOW PRESSURE WAS
DEEPENING OVER CENTRAL IOWA WITH A WARM FRONT EXTENDING FROM
CENTRAL IOWA EAST ACROSS NORTHERN ILLINOIS. THE LOW WILL LIFT
NORTHEAST THIS AFTERNOON PULLING THE WARM FRONT NORTH INTO
NORTHEAST IOWA/SOUTHWEST WISCONSIN. MEANWHILE...THE SHORTWAVE WILL
TRACK SOUTHEAST ACROSS NORTHER IOWA/SOUTHERN MINNESOTA. THE
TIMING OF THE WAVE AND THE PROXIMITY OF THE WARM FRONT...ALONG
WITH INCREASING INSTABILITY....WILL CREATE FAVORABLE CONDITIONS
FOR SEVERE THUNDERSTORMS. 0-6 KM SHEAR OF 60 KTS AND 0-1 KM SHEAR
OF AROUND 20KTS...LOCALLY ENHANCED NEAR THE WARM FRONT/SURFACE
LOW...WILL BE VERY FAVORABLE FOR DISCRETE SUPERCELLS CAPABLE OF
PRODUCING TORNADOES. A FEW STORMS MAY ALSO PRODUCE LOCALIZED FLASH
FLOODING.
&&
.SHORT TERM...(TODAY THROUGH THURSDAY)
ISSUED AT 318 AM CDT WED JUN 12 2013
MAIN CONCERN FOR TODAY INTO THIS EARLY EVENING WILL BE SEVERE
THUNDERSTORM THREAT ACROSS THE SOUTH.
WATER VAPOR IMAGERY/RAP 500MB HEIGHT FIELD SHOWS A VIGOROUS
SHORTWAVE TROUGH MOVING OUT OF MT/WY INTO WESTERN ND/SD/NE. SURFACE
MAP AS OF 2 AM HAD AN AREA OF LOW PRESSURE ALONG THE KS/NE BORDER
WITH A WARM FRONT EXTENDING ENE ALONG I-80 IN IA AND IL. 850MB
MOISTURE TRANSPORT/ISENTROPIC LIFT AHEAD OF THE LOW AND OVER THE
WARM FRONT WAS PRODUCING SCATTERED ELEVATED SHRA/TS ACROSS OUR
FORECAST AREA...WITH A MORE INVIGORATED N-S LINE OF STORMS ACROSS
CENTRAL SD WHICH WAS HEADED EAST AROUND 50KT. RAP CORFIDI VECTORS
TAKE THIS COMPLEX OF STORMS DUE EAST AT 55-65KT THIS MORNING...WHICH
WOULD BRING IT INTO OUR AREA IN THE 7-9 AM TIME FRAME. MEANWHILE...A
NEW COMPLEX OF THUNDERSTORMS WERE FIRING ACROSS NORTHWEST
IA...MOVING TOWARD THE EAST. THIS CONVECTION WAS ROOTED A BIT CLOSER
TO THE CAPE POOL JUST NORTH OF THE 925-850MB WARM FRONT. A COUPLE
OBS IN SD WHERE THIS LINE PASSED RECORDED 43/48KT. HOWEVER...WRF
MODELS...NAMELY THE 12.00Z NSSL WRF WHICH SEEMS TO HAVE THE BEST
HANDLE ON THE CONVECTION RIGHT NOW...HAS THIS CONVECTION DECAYING AS
IT MOVES INTO THE AREA IN THE 5-8AM TIME FRAME. WITH 0-3KM BULK
SHEAR IN THE 40-50KT RANGE AND 0-3KM ML MUCAPE HOVERING IN THE
1000-2000J/KG...WILL HAVE TO WATCH THIS ONGOING CONVECTION CAREFULLY
FOR A SEVERE WIND THREAT EARLY THIS MORNING.
THERE THEN SEEMS TO BE A BREAK IN THE ACTION FROM MID-MORNING UNTIL
EARLY AFTERNOON BEFORE THE MID-LEVEL TROUGH AND SURFACE LOW MOVE
ACROSS EASTERN IA IN THE 18Z-21Z TIME FRAME. THIS TROUGH/STEEPENING
MID LEVEL LAPSE RATES THEN INTERACTS WITH 2000-3500J/KG 0-1KM ML
MUCAPE POOL IN PLACE SOUTH OF I-90 TO FIRE VIGOROUS/DEEP
CONVECTION. COOLING MID LEVEL/STEEPER LAPSE RATES AND 0-3KM BULK
SHEAR IN THE 20-40KT RANGE WILL SUPPORT A SEVERE HAIL/WIND THREAT
SOUTH OF I-90. AND...WITH THE JUXTAPOSITION OF THE LOW/WARM FRONT
PRODUCING FAVORABLE 0-3KM SRH...CANNOT RULE OUT A TORNADIC THREAT
ACROSS PORTIONS OF NORTHEAST IA INTO FAR SOUTHWEST WI...NAMELY
FAYETTE AND CLAYTON COUNTIES IN NORTHEAST IA AND GRANT COUNTY IN WI.
LOCALIZED FLOODING IS ALSO A CONCERN WITH THIS CONVECTION AS
PRECIPITABLE WATER VALUES HOVER IN THE 1.5 TO 2 INCH RANGE. SEE
HYDROLOGY SECTION BELOW FOR FURTHER DETAILS ON HEAVY RAIN POTENTIAL
AND IMPACTS. PLAN ON THE LOW AND ASSOCIATED CONVECTION TO MOVE
SOUTHEAST OF THE REGION AROUND MIDNIGHT TONIGHT. HIGH PRESSURE THEN
STARTS NOSING IN AFTER MIDNIGHT FROM THE NORTHERN PLAINS FOR
CLEARING SKIES.
HIGH PRESSURE WILL BE IN CONTROL ON THURSDAY WITH PLEASANT
TEMPERATURES IN THE 70S AND LOWER HUMIDITY LEVELS.
.LONG TERM...(THURSDAY NIGHT THROUGH TUESDAY)
ISSUED AT 318 AM CDT WED JUN 12 2013
HIGH PRESSURE REMAINS IN CONTROL ACROSS THE AREA THURSDAY NIGHT
THROUGH FRIDAY MORNING FOR A CONTINUED DRY RESPITE. BY FRIDAY
AFTERNOON THOUGH...A TROUGH OF LOW PRESSURE OVER THE PLAINS BEGINS
TO SHOVE MOISTURE BACK INTO THE AREA...MAINLY WEST OF THE
MISSISSIPPI RIVER FOR A CHANCE OF SHOWERS/ISOLATED THUNDER. FOR
FRIDAY NIGHT THROUGH SATURDAY EVENING...LOOK FOR LOW PRESSURE OVER
CANADA TO SEND A COLD FRONT THROUGH THE AREA. THIS WILL PRODUCE THE
LIKELIHOOD OF SHOWERS AND THUNDERSTORMS. WILL NEED TO WATCH FOR THE
POSSIBILITY OF SEVERE WEATHER GIVEN 0-1KM ML MUCAPE IN THE
1500-3500J/KG AND MODEST AMOUNT OF 0-3KM BULK SHEAR. LINGERING
MID-LEVEL TROUGH/FAIRLY STEEP LAPSE RATES ENOUGH TO WARRANT A
LOWER-END SHRA/TS CHANCE SUNDAY THROUGH MONDAY. NORTHWEST FLOW AND
ANOTHER WEAK MID-LEVEL TROUGH IN THIS FLOW PRODUCE ANOTHER SHRA/TS
CHANCE ON TUESDAY. OTHERWISE... LOOKS LIKE TEMPERATURES WILL BE
RIGHT AROUND NORMAL THROUGH THE PERIOD...MAINLY IN THE 70S.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1214 PM CDT WED JUN 12 2013
A VIGOROUS UPPER LEVEL DISTURBANCE WILL BRING SHOWERS AND
THUNDERSTORMS TO THE TAF SITES THIS AFTERNOON INTO EARLY THIS
EVENING. A FEW STORMS COULD BECOME SEVERE WITH LARGE
HAIL...DAMAGING WINDS. AN ISOLATED TORNADO IS ALSO POSSIBLE BUT
THE HIGHER CHANCES WILL BE ACROSS NORTHEAST IOWA AND FAR SOUTHWEST
WISCONSIN. MVFR TO IFR CONDITIONS ARE POSSIBLE IN THE
THUNDERSTORMS THIS AFTERNOON. A COLD FRONT WILL PUSH ACROSS THE
AREA THIS EVENING WITH WINDS SWITCHING TO THE NORTHWEST. AFTER A
BRIEF PERIOD OF MVFR STRATUS RIGHT BEHIND THE FRONT...VFR
CONDITIONS ARE EXPECTED LATE TONIGHT INTO THURSDAY MORNING.
&&
.HYDROLOGY...TODAY INTO THIS EVENING
ISSUED AT 318 AM CDT WED JUN 12 2013
FOR AREAS MAINLY ALONG AND SOUTH OF I-90...EXPECTING RAINFALL
AMOUNTS FROM TODAY INTO THIS EVENING IN THE 0.75 TO 1.25 INCH RANGE
WITH THE POSSIBILITY OF LOCALLY HIGHER AMOUNTS IN THUNDERSTORM
ACTIVITY. GIVEN THE WET SOILS IN PLACE...PLAN ON SOME RUNOFF ISSUES
WITH PONDING OF WATER AND SOME SIGNIFICANT WITHIN BANK RIVER RISES.
ANY LONGER DURATION/HIGHER RAINFALL RATES WOULD INCREASE THE
FLOODING POTENTIAL. STAY TUNED.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
UPDATE...WETENKAMP
SHORT TERM...DAS
LONG TERM....DAS
AVIATION...WETENKAMP
HYDROLOGY....DAS