Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 08/03/13
AREA FORECAST DISCUSSION
NWS TUCSON AZ
910 AM MST THU AUG 1 2013
.SYNOPSIS...SCATTERED MAINLY AFTERNOON AND EVENING THUNDERSTORMS
WILL CONTINUE INTO NEXT WEEK WITH NEAR NORMAL TEMPERATURES.
&&
.DISCUSSION...LOTS OF DEBRIS CLOUD WITH EMBEDDED WEAK CONVECTION
THIS MORNING. MOISTURE PLENTIFUL WITH 12Z KTWC SOUNDING COMING IN
WITH 1.65 AND 1.6 TO 1.7 INCHES A COMMON VALUE ACROSS SOUTHEAST
ARIZONA ON BLENDED SATELLITE ESTIMATES. CONDITIONAL INSTABILITY ON
SOUNDING NOT THE BEST...SUGGESTING EASY MOUNTAIN DEVELOPMENT AND
MODEST OUTFLOW SUPPORT FOR ESPECIALLY EASTERN VALLEYS. SLOW MOVING
HEAVY RAIN A CONCERN. EARLIER UPDATE TO EMPHASIZE CLOUD COVER AND TO
KNOCK A DEGREE OR TWO OFF HIGH TEMPERATURES. HRRR HINTING AT A LATE
AFTERNOON OR EARLY EVENING TIME FOR A FEW SLOW MOVING STORMS
SPREADING INTO ADDITIONAL VALLEY LOCATIONS.
&&
.PREV DISCUSSION...CONSIDERABLE DEBRIS CLOUDINESS ACROSS THE AREA
THIS MORNING. MUCH FURTHER SOUTH...THERE WAS AN MCS SOUTH OF GUYMAS
MOVING INTO THE GULF OF CALIFORNIA. OUTFLOW FOR THIS COMPLEX LIKELY
TO SEND UP A SURGE OF LOW LEVEL MOISTURE UP THE GULF TODAY. MOISTURE
IS BACK WITH PRECIPITABLE WATER VALUES THIS MORNING IN THE 1.45" TO
1.60" RANGE. SOUTHERLY FLOW WILL BE AROUND INTO THE WEEKEND AND
EARLY NEXT WEEK WITH UPPER LEVEL HIGH OVER TEXAS. SHOULD SEE AN
UPTICK IN AREAL COVERAGE OF STORMS TODAY...WITH SCATTERED MAINLY
AFTERNOON AND EVENING STORMS CONTINUING FOR THE NEXT 7 DAYS. HARD TO
PICK OUT WHICH DAY WILL BE MORE ACTIVE THAN ANOTHER. SO BASICALLY
KEPT NEAR CLIMO POPS IN THE FORECAST. HIGHS TODAY WILL BE SLIGHTLY
ABOVE NORMAL...THEN GRADUALLY COOL TO NEAR NORMAL OVER THE NEXT
SEVERAL DAYS.
&&
.AVIATION...SCT-BKN CLOUDS AT 6-10K FT AGL. ISOLD TSRA INCREASING TO
SCT AFT 01/19Z...MAINLY FROM KTUS SOUTH AND EAST INCLUDING
THE KOLS AND KDUG TERMINALS THRU 02/05Z. WIND GUSTS TO 45 KTS NEAR
ANY TSRA...AS WELL AS LOCAL MVFR/IFR CIGS/VSBYS. OTHERWISE...SURFACE
WIND GENERALLY LESS THAN 10 KTS THRU 02/16Z. AVIATION DISCUSSION NOT
UPDATED FOR TAF AMENDMENTS.
&&
.FIRE WEATHER...MOISTURE WILL REMAIN IN PLACE ACROSS THE AREA INTO
NEXT WEEK...RESULTING IN A CHANCE OF MAINLY AFTERNOON AND EVENING
SHOWERS AND THUNDERSTORMS ACTIVITY ACROSS MOST OF SOUTHEAST ARIZONA.
OUTSIDE OF GUSTY THUNDERSTORM OUTFLOWS...WINDS DURING THIS PERIOD
ARE EXPECTED TO BE LIGHT...GENERALLY LESS THAN 15 MPH...AND
DIURNALLY DRIVEN.
&&
.CLIMATE...JULY 2013 FOR TUCSON GOES INTO THE RECORDS BOOKS AS THE
19TH WARMEST AND 38TH WETTEST ON RECORD. THE JULY CLIMATE REPORT FOR
TUCSON WILL BE POSTED LATER THIS MORNING ON OUR WEBSITE...FACEBOOK
AND ON TWITTER.
AFTER DOUGLAS RECORDED ITS WETTEST ANY MONTH ON RECORD DURING JULY
WITH 10.12"...THE MAIN STORY DOWN THERE FOR THE REMAINDER OF THE
2013 MONSOON IS THEIR ATTEMPT AT RECORDING THE WETTEST MONSOON ON
RECORD. DOUGLAS IS CURRENTLY 5.67" FROM THE RECORD OF 15.90" THAT
OCCURRED IN 1964. DATING BACK TO 1948...THERE HAVE BEEN THIRTEEN
OCCURRENCES WHICH RECORDED MORE THAN 5.67" FOR THE REMAINDER OF THE
MONSOON PERIOD. COMBINED NORMAL RAINFALL FOR AUGUST/SEPTEMBER IN
4.59". SINCE 1948...DOUGLAS HAS RECORD MORE THAN THE NORMAL TOTAL 27
TIMES. UNLESS SOMETHING REALLY ODD HAPPENS AT DOUGLAS AIRPORT...A
TOP 5 WETTEST MONSOON ON RECORD IS MOST DEFINITE.
&&
.TWC WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...YOUTUBE...AND AT WEATHER.GOV/TUCSON
AREA FORECAST DISCUSSION
NWS FLAGSTAFF AZ
925 PM MST WED JUL 31 2013
.SYNOPSIS...
SHOWERS AND ISOLATED THUNDERSTORMS MAY CONTINUE OVERNIGHT AS A
DISTURBANCE APPROACHES FROM THE SOUTHEAST. DAYTIME THUNDERSTORM
COVERAGE SHOULD INCREASE ON THURSDAY AND FRIDAY RELATIVE TO
COVERAGE SEEN THIS AFTERNOON.
&&
.DISCUSSION...
WE UPDATED THE FORECAST GRIDS EARLIER THIS EVENING TO REFLECT
GREATER PRECIP CHANCES IN SOUTHEAST PORTIONS OF THE COUNTY WARNING
AREA AS A WEAK SHORT WAVE TROUGH MOVES TOWARD NORTHERN AZ FROM THE
SOUTHEAST. IN ADDITION...AN MCV IS APPARENT IN SOUTHWEST NAVAJO
COUNTY. WE RAISED OVERNIGHT MINIMUM TEMPERATURES IN ANTICIPATION
OF THICK CLOUD COVER OVER MUCH OF THE AREA.
&&
.PREVIOUS DISCUSSION /330 PM MST/...
SCATTERED SHOWERS AND THUNDERSTORMS DEVELOPED FROM
NEAR DESERT VIEW AT THE GRAND CANYON...MOGOLLON RIM...TO THE WHITE
MOUNTAINS TODAY. THE STORMS ARE MOVING NORTHWARD INTO THE LCR THIS
AFTERNOON. THIS ACTIVITY IS EXPECTED TO CONTINUE INTO THIS EVENING.
VISIBLE SATELLITE SHOWED SEVERAL UPPER DISTURBANCES OVER NORTHERN
MEXICO THIS MORNING. THESE DISTURBANCES ARE MORNING NORTHWARD AND
MAY WELL CONTINUE THUNDERSTORM ACTIVITY WELL INTO THE NIGHT OVER
NORTHERN ARIZONA. THE 17Z RUN OF THE HRRR SHOWED RAIN SHOWERS
RE-DEVELOPING OVER THE RIM COUNTRY LATE THIS EVENING. HAVE KEPT
CHANCE POPS GOING THROUGH THE NIGHT FOR THE HIGHER TERRAIN OVER MUCH
OF NORTHERN ARIZONA.
HIGH PRESSURE WILL REMAIN EAST OF ARIZONA FOR THE NEXT WEEK. ARIZONA
WILL BE ON THE WESTERN EDGE OF THE HIGH WITH A SOUTH TO SOUTHWEST
FLOW OVER THE STATE. THE GFS AND EC ARE AT ODDS ON HOW MUCH MOISTURE
WILL MOVE OVER THE STATE AND IF/WHEN SIGNIFICANT DRYING WILL HAPPEN.
FORECAST LEANS MORE TOWARD THE EC GIVEN HOW IT HAS HANDLED THE
WETTER PATTERN SO FAR THIS SUMMER.
SHOWER AND THUNDERSTORM COVERAGE SHOULD INCREASE EACH DAY ACROSS
THE AREA THROUGH FRIDAY AND THEN REMAIN FAIRLY CONSTANT THROUGH THE
WEEKEND.
&&
.AVIATION...
FOR THE 06Z PACKAGE...MONSOON MOISTURE IS ON THE INCREASE.
AT LEAST ISOLATED THUNDERSTORMS MAY CONTINUE THROUGH THE OVERNIGHT
HOURS...WITH AREAS OF RAIN SHOWERS ESPECIALLY SOUTHEAST OF A
KPAN/KFLG/KRQE LINE. MVFR VISIBILITY MAY OCCUR IN AREAS OF
RAINFALL. THUNDERSTORMS WILL DEVELOP AGAIN ON THURSDAY AFTER 18Z
WITH THE ATTENDANT THREATS OF LOWERED VISIBILITY AND GUSTY WINDS. AVIATION
DISCUSSION NOT UPDATED FOR AMENDMENTS.
&&
.FIRE WEATHER...
MONSOON MOISTURE WILL PUSH BACK ACROSS NORTHERN
ARIZONA WITH AN INCREASING CHANCE OF SHOWERS AND THUNDERSTORMS ON
THURSDAY AND FRIDAY.
SATURDAY THROUGH MONDAY...THE CHANCE FOR SHOWERS AND THUNDERSTORMS
WILL CONTINUE OVER NORTHERN ARIZONA.
&&
.FGZ WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
PUBLIC.........AT/MAS
AVIATION.......AT
FIRE WEATHER...MCCOLLUM
FOR NORTHERN ARIZONA WEATHER INFORMATION VISIT
WEATHER.GOV/FLAGSTAFF
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
819 PM MDT FRI AUG 2 2013
.UPDATE...CONVECTION CONTINUES TO FIRE ALONG THE FRONT RANGE THIS
EVENING. STRONGEST STORMS AND HIGHEST COVERAGE WAS OCCURRING IN
LARIMER AND WELD COUNTIES WHERE BETTER SURGE OF LOW LEVEL MOISTURE
HAD PUSHED ALL THE WAY BACK INTO THE FOOTHILLS. EVEN THE SHORT
RANGE MODELS WERE STRUGGLING WITH THIS SO BASED FORECAST HEAVILY
ON MESOSCALE AND RADAR ANALYSIS. HAVE INCREASED POPS FOR THE
NORTHERN FRONT RANGE DUE TO THE BETTER SURGE OF LOW LEVEL MOISTURE
THERE. CONVECTIVE ACTIVITY SHOULD SLOWLY DECREASE AFTER MIDNIGHT
BUT LIKE THE IDEA OF SOME POPS ALONG/EAST OF THE FRONT RANGE
THROUGH THE NIGHT.
&&
.AVIATION...CONVECTION AND THEIR ASSOCIATED BOUNDARIES WILL
CONTINUE TO BE MONITORED CLOSELY OVER THE NEXT FEW HOURS. CHANCE
OF STRATUS AND IFR CEILINGS 11Z-15Z DUE TO LOW LEVEL MOISTURE...
IF SURGE EVER MAKES IT THROUGH THE FRONT RANGE AIRPORTS.
&&
.HYDROLOGY...NORTHERN BURN SCAR...MAINLY HIGH PARK...WILL BE
SUSCEPTIBLE TO HEAVIER RAIN THIS EVENING WHICH COULD PRODUCE
FLOODING. THIS IS DUE TO EARLIER ARRIVAL OF DEEPER MOISTURE THERE.
&&
.PREV DISCUSSION... /ISSUED 316 PM MDT FRI AUG 2 2013/
SHORT TERM...AS EXPECTED...THE COLD FRONT OUT OF NE/SD HAS MOVED
INTO NORTHEASTERN COLORADO ALREADY...PUSHED QUICKER BY LAST NIGHT
AND THIS MORNINGS CONVECTION UP THERE. THIS IS ABOUT 12 HOURS
AHEAD OF WHAT THE GFS...ECMWF...NAM AND GEM MODELS HAD IT COMING
IN....THE HRRR AND THE RUC MODELS HAVE BEEN SHOWING AN EARLIER
ARRIVAL WITH EACH HOURLY RUN. HAVE ADJUSTED WIND AND WEATHER
GRIDS FOR AN EARLIER ARRIVAL.
A BUILDING UPPER RIDGE CONTINUES TO STRETCH FROM TEXAS NORTHWEST
INTO MONTANA TONIGHT INTO SATURDAY. HIGH SURFACE PRESSURE OVER THE
HIGH NORTHERN PLAINS WILL CONTINUE MOVING SOUTH AND PUSH THE COLD
FRONT FURTHER SOUTH DOWN THE EASTERN PLAINS OF COLORADO. FRONTAL
LIFT WILL CONTINUE PRODUCING ISOLATED SHOWERS AND THUNDERSTORMS
OVER THE PLAINS THROUGH TONIGHT WITH OROGRAPHIC LIFT KEEPING
ISOLATED STORMS GOING OVER THE HIGHER TERRAIN THROUGH THE
EVENING.
HIGHER MOISTURE WILL BE PUSHED IN FROM THE EAST THROUGH
SATURDAY...WITH PRECIPITABLE WATER CURRENTLY AROUND 0.7 INCHES AND
FORECASTED TO INCREASE TO NEAR 1.5 INCHES BY SATURDAY AFTERNOON.
THIS WILL HELP INCREASE CAPES UP TO NEAR 1500 J/KG OVER THE
PLAINS...THEN EASTERLY FLOW AT THE SURFACE TRANSITIONING TO
INCREASING SOUTHERLIES NEAR 700 MB THEN WESTERLIES NEAR 500 MB
WILL PROVIDE ENOUGH SHEAR FOR MAKING THE ENVIRONMENT ABLE TO
PRODUCE AND CARRY STRONGER STORMS. TEMPERATURES WILL BE COOLER AT
THE SURFACE OVER THE FOOTHILLS AND PLAINS TOMORROW WITH LOW 80S
EXPECTED. MOUNTAINS SHOULD STAY ABOVE THIS FRONTAL AIRMASS WITH
SIMILAR TEMPERATURES TO TODAY AND ISOLATED TO SCATTERED
CONVECTION. AREAS ALONG AND EAST OF THE CONTINENTAL DIVIDE WILL
SEE MORE WIDESPREAD SHOWERS AND STORMS WITH THE UPSLOPE FLOW.
RAINFALL AMOUNTS ARE EXPECTED TO BE GREATER WITH THE STRONG STORMS
WHERE A SINGLE STORM COULD PRODUCE HALF AN INCH OR MORE. THESE
STORMS WILL ALSO HAVE THE THREAT OF STRONG WINDS AND LARGE HAIL
UNDER TOMORROWS EXPECTED ENVIRONMENT. NAM MODEL IS AN OUTLIER
WITH THE FRONT AND SURFACE TROUGH MOVING BACK EAST INTO THE PLAINS
WHICH WOULD DRASTICALLY LOWER THE CHANCE OF PRECIPITATION ALONG
THE FOOTHILLS AND METRO AREAS. WITH THIS MODEL BEING THE ONLY ONE
SHOWING THIS PATTERN....WILL DISCOUNT FOR NOW...BUT NOT TOTALLY
DISREGARD THE POSSIBILITY.
LONG TERM...MID LEVEL SHORTWAVE TO MOVE ACROSS FAR EASTERN PLAINS
SATURDAY EVENING. BEST CHANCE FOR STORMS DURING THE EVENING TO
BE ALONG AND AHEAD OF THE WAVE ACROSS FAR EASTERN PLAINS AND WILL
KEEP THE HIGHER POPS THERE. CAPE VALUES TO DECREASE DURING THE
EVENING TO LESS THAN 1000 J/KG...SO ANY THREAT FOR SEVERE STORMS
SHOULD HAVE ENDED. STILL POTENTIAL FOR STORMS TO PRODUCE BRIEF
HEAVY RAINFALL...ESPECIALLY FAR EASTERN PLAINS AND ALONG
FOOTHILLS. STORMS TO END OVERNIGHT WITH SOME CLEARING. BOUNDARY
LAYER WIND AND HUMIDITY PROGS SUGGEST SOME POTENTIAL FOR FOG OVER
THE FAR NORTHEAST CORNER TOWARDS MORNING. FOR NOW WILL HOLD OFF ON
ADDING ANY FOG. ON SUNDAY...FLOW ALOFT BECOMES A BIT MORE WESTERLY
WITH A SLIGHT DECREASE IN MOISTURE. PRECIPITABLE WATER VALUES
STILL FAIRLY HIGH ACROSS PLAINS WITH VALUES ABOVE AN INCH. STILL
BEST CHANCE FOR STORMS TO BE ACROSS MOUNTAINS AND FOOTHILLS AS
WELL AS ALONG THE PALMER DIVIDE DURING THE AFTERNOON AND EVENING
AS FORECAST SOUNDINGS SHOWING A MID LEVEL CAP OVER MUCH OF THE
PLAINS. THERE ARE SOME HINTS OF THE DEVELOPMENT OF A DENVER
CYCLONE WHICH COULD FOCUS ADDITIONAL STORM DEVELOPMENT EAST OF THE
URBAN CORRIDOR. TEMPERATURES TO BE A FEW DEGREES WARMER...CLOSER
TO NORMAL READINGS. FOR MONDAY...MODELS SHOW WESTERLY FLOW ALOFT
INCREASING WITH UPPER HIGH CENTERED OVER NORTHERN TEXAS. AIRMASS A
BIT DRIER...WITH PRECIPITABLE WATER VALUES AROUND NINE TENTHS OF
AN INCH ACROSS THE PLAINS AND SIX TENTHS OF AN INCH OVER THE
MOUNTAINS. STILL ENOUGH MOISTURE OF A SLIGHT CHANCE OF AFTERNOON
AND EVENING THUNDERSTORMS....MAINLY OVER THE MOUNTAINS. HIGHS TO
BE NEAR NORMAL. ON TUESDAY...CENTER OF UPPER HIGH SHIFTS INTO
EASTERN TEXAS WITH FLOW BECOMING SOUTHWEST. SOME INCREASE IN
SUBTROPICAL MOISTURE DURING THE AFTERNOON...MAINLY ACROSS
MOUNTAINS. BEST CHANCE FOR STORMS TO BE OVER THE HIGH COUNTRY.
HIGHS TO HOVER NEAR NORMAL.
FOR THE LATER DAYS...WEDNESDAY THROUGH FRIDAY: SOUTHWEST FLOW
ALOFT TO PREVAIL WITH UPPER HIGH SHIFTING INTO ARKANSAS BY FRIDAY.
SUBTROPICAL MOISTURE TO INCREASE WEDNESDAY AND THURSDAY WITH A
BETTER CHANCE FOR THUNDERSTORMS. IN ADDITION...MODELS SHOW A FRONT
MOVING ACROSS THE PLAINS WEDNESDAY...INCREASING THE UPSLOPE AND
LOW LEVEL MOISTURE. BY FRIDAY THERE IS SOME HINTS AT THE MOISTURE
DECREASING WITH A MORE STABLE AIRMASS WHICH SHOULD LEAD TO A LOWER
CHANCE FOR THUNDERSTORMS. TEMPERATURES TO COOL TO BELOW NORMAL BY
FRIDAY.
AVIATION...VFR CONDITIONS WILL PREVAIL TODAY WITH LIGHT WINDS.
A SLIGHT CHANCE AT SEEING A THUNDERSTORM LATE THIS AFTERNOON AND
EVENING WITH THE BEST CHANCE OVER THE HIGH TERRAIN AND NEAR THE WY
BORDER. GOOD POSSIBILITY OF OUTFLOW AT THE AREA AIRPORTS FROM
STORMS...REASON FOR VRB20G30KT. A COLD FRONT WILL BE MOVING SOUTH
ACROSS THE AREA TONIGHT WHICH WILL BRING IN HIGHER MOISTURE AND
UPSLOPE FLOW. MUCH MORE WIDESPREAD CONVECTION EXPECTED SATURDAY.
HYDROLOGY...AIRMASS IS DRIER AND MORE STABLE TODAY LEAVING
ISOLATED COVERAGE OF THUNDERSTORMS THIS AFTERNOON AND EVENING.
MODERATE TO A VERY BRIEF PERIOD OF HEAVY RAIN WILL BE POSSIBLE
FROM THE STORMS THAT DO DEVELOP...UP TO A THIRD OF AN INCH FROM A
STRONG STORM. MOISTURE WILL INCREASE BEHIND A FRONT TONIGHT AND
BRING A GOOD CHANCE FOR STORMS SATURDAY. THESE STORMS WILL BE
CAPABLE OF PRODUCING HEAVY RAIN...POSSIBLY UP TO AN INCH PER HOUR
OR LESS FROM A STRONG STORM.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...BARJENBRUCH
LONG TERM....D-L
AVIATION...BARJENBRUCH
AREA FORECAST DISCUSSION
NWS PUEBLO CO
344 PM MDT THU AUG 1 2013
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 342 PM MDT THU AUG 1 2013
CURRENTLY...SHORTWAVE TROUGH AND UPPER VORT MAX ARE CURRENTLY
EJECTING EASTWARD ACROSS COLORADO...WHILE A SECONDARY WAVE MOVES
NORTHWARD OUT OF NEW MEXICO INTO SOUTHERN COLORADO. RADAR INDICATES
WIDESPREAD CONVECTION OVER THE MOUNTAIN AREAS AND SPREADING EAST
INTO THE I-25 CORRIDOR. TEMPERATURES HAVE BEEN WARM WITH UPPER 80S
TO LOWER 90S FOR THE PLAINS.
THROUGH TONIGHT...MODELS HAVING A HARD TIME WITH THIS UPPER LEVEL
DISTURBANCE AND THE AMOUNT OF CONVECTION FIRING ACROSS THE REGION.
THE LATEST RAP AND HRRR SEEM TO HAVE A BETTER HANDLE WITH THE LATEST
RUNS WITH CONVECTION SPREADING EAST ACROSS THE PLAINS THROUGH THE
EVENING HOURS. DEW POINTS IN THE UPPER 50S AND PWAT VALUES
APPROACHING AN INCH HAVE LED TO LOCALLY HEAVY RAINFALL WITH THESE
THUNDERSTORMS. OF CONCERN ARE AREA BURN SCARS...WHICH COULD SEE
LOCALIZED FLASH FLOODING WITH ANY HEAVY CELLS THAT MOVE OVER THEM.
WHILE THE WEST FORK COMPLEX HAS ONLY SEEN LIGHT PRECIP SO FAR
TODAY...THE UPPER DISTURBANCE MOVING NORTH OUT OF NEW MEXICO SHOULD
PROVIDE ENHANCED LIFT AND CONTINUED THREAT FOR HEAVY RAINFALL
THROUGH THIS EVENING. NOT MUCH OF A SEVERE WEATHER THREAT ACROSS
THE PLAINS THIS EVENING. THERE COULD BE SOME DIME TO PENNY SIZE
HAIL WITH THE STRONGEST CELLS...ESPECIALLY SOUTH OF HIGHWAY 50
THROUGH ABOUT 9PM TONIGHT. EXPECT MOST ACTIVITY TO SHIFT EAST WITH
THE UPPER WAVE AFTER MIDNIGHT WITH SHOWER AND THUNDERSTORM ACTIVITY
COMING TO AN END THROUGH FRIDAY MORNING. THE EXCEPTION WILL BE THE
SAN JUAN RANGE WHERE THE EJECTING UPPER DISTURBANCE WILL LIKELY KEEP
THUNDERSTORMS GOING INTO FRIDAY MORNING.
FRIDAY...THE UPPER LEVEL DISTURBANCE OUT OF NEW MEXICO WILL TRACK
INTO SOUTHWEST KANSAS BY FRIDAY AFTERNOON WHILE A WEAK BOUNDARY
SHIFTS SOUTH INTO THE PLAINS. DRIER AIR AND SUBSIDENCE BEHIND THE
DEPARTING WAVE SHOULD LIMIT THUNDERSTORM ACTIVITY TO THE MOUNTAIN
AREAS...AND NEAR THE NEW MEXICO BORDER. THE MAIN THREATS WILL
CONTINUE TO BE LOCALIZED HEAVY RAINFALL AND LIGHTNING. GIVEN THE
DECREASE IN MOISTURE...THE FLASH FLOOD RISK WILL LIKELY BE MINIMAL
OVER THE WEST FORK COMPLEX...BUT ANY CELLS THAT DO MOVE OVER THE
BURN SCAR COULD PRODUCE A QUICK BURST OF RAINFALL. TEMPERATURES
WILL REMAIN WARM WITH AFTERNOON HIGHS IN THE MID TO UPPER 90S ACROSS
THE LOWER ELEVATIONS. MOZLEY
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 342 PM MDT THU AUG 1 2013
...SUMMER MONSOON WILL STICK AROUND FOR A WHILE...
ALL IN ALL...GOOD NEW IN THE WEATHER DEPARTMENT...THE SUMMER MONSOON
LOOKS ALIVE AND WELL THROUGH AT LEAST NEXT WEEK. THERE WILL BE
WETTER DAYS AND DRIER DAYS...BUT THE MONSOON PLUME WILL GENERALLY
REMAIN OVER COLORADO. NOT EVERYONE WILL GET RAIN EVERYDAY...SUMMER
CONVECTION IS PRETTY MUCH ALWAYS HIT OR MISS. BUT...OVER
TIME...MOST WILL GET THERE SHARE OF THE MONSOON...MAYBE ONLY 1 DAY
IN THE NEXT 7...MAYBE 2 DAYS...MAYBE EVEN 3 DAYS OR MORE. BUT...THE
SHOWERS WILL BE AROUND...AND THE HUMIDITIES WILL BE UP...ALL GOOD
FOR COLORADO. WELL...MAYBE NOT SO GOOD FOR THE BURN SCAR AREAS...OF
COURSE.
FRIDAY LOOKS A BIT DRIER...BUT STILL MOIST ENOUGH FOR ISOLATED TO
SCATTERED AFTERNOON AND EVENING THUNDERSTORMS ACROSS THE
AREA...ESPECIALLY MOUNTAINS AND RIDGES.
SATURDAY CONTINUES TO LOOK LIKE A GOOD CHANCE OF SHOWERS OVER MOST
OF THE AREA...BUT ESPECIALLY FOR THE EASTERN MOUNTAINS AND PLAINS.
A SIGNIFICANT SURFACE BOUNDARY IS STILL POISED TO MOVE THROUGH THE
EASTERN PLAINS THIS DAY AND INTERACT WITH THE MONSOON PLUME...TO
PRODUCE MORE WIDESPREAD PRECIPITATION THAN TYPICAL. WITH THE
GREATER NUMBER OF SHOWERS AROUND...AND THE GREATER LIFTING PROVIDED
BY THE SURFACE BOUNDARY...THIS WILL INCREASE THE HEAVY RAIN
POTENTIAL AT ANY ONE LOCATION THIS DAY. SO...THE BURN SCAR FLASH
FLOOD THREAT WILL BE UP.
SUNDAY LOOKS A BIT DRIER...BUT STILL MOIST ENOUGH FOR
CONVECTION...ESPECIALLY MOUNTAINS AND RIDGES AGAIN.
LATER MONDAY THROUGH THE REMAINDER OF THE WEEK CONTINUES TO LOOK
INTERESTING WITH THE CHANCES FOR AFTERNOON AND NIGHTLY SHOWERS AND
THUNDERSTORMS GOING UP THROUGH THE PERIOD. STARTING MONDAY
NIGHT...A SERIES OF SURFACE BOUNDARIES WILL START TO MOVE THROUGH
THE EASTERN HALF OF THE FORECAST AREA. THESE BOUNDARIES WILL BE
TIED TO A SLOWLY MOVING BROAD UPPER LEVEL TROUGH DROPPING SOUTHWARD
THROUGH THE NORTHERN PLAINS DURING THE PERIOD. THE JET STREAM ON
THE SOUTH SIDE OF THIS TROUGH WILL TEND TO SEND SURFACE BOUNDARIES
SOUTH THROUGH THE PLAINS ON A REGULAR BASIS...THUS...INCREASING THE
AMOUNT OF LOW LEVEL UPSLOPE FLOW OVER THE EAST. THE INCREASED
LIFTING OF THE AIR ASSOCIATED WITH THE UPSLOPE COMBINED WITH A
STRONG MONSOON PRESENCE WILL SET THE STAGE FOR REPEATED ROUNDS OF
SHOWERS...HEAVY AT TIMES...THROUGH THE PERIOD. IF CURRENT FORECASTS
VERIFY...THE BURN SCAR AREAS WILL LIKELY NEED TO BE ON HIGH ALERT
MOST OF NEXT WEEK. LW
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z FRIDAY EVENING)
ISSUED AT 342 PM MDT THU AUG 1 2013
KALS...WIDESPREAD SHOWER AND THUNDERSTORM ACTIVITY IS IMPACTING THE
MOUNTAIN AREAS AROUND THE SAN LUIS VALLEY...WITH SEVERAL CELLS
MOVING IN AND AROUND THE TERMINAL. THIS ACTIVITY SHOULD PERSIST
THROUGH MUCH OF THE EVENING...THROUGH AT LEAST 08Z TONIGHT. REDUCED
VIS AND CIGS ARE LIKELY TO IFR CONDITION. DRIER CONDITIONS ARE
FORECAST TO MOVE INTO THE SAN LUIS VALLEY BY FRIDAY MORNING.
KCOS AND KPUB...BAND OF SPOTTY THUNDERSTORMS IN A LINE FROM KCOS TO
SOUTH OF KPUB IS MOVING EAST. FOR NOW IT LOOKS LIKE BOTH TERMINALS
WILL JUST HAVE CELLS IN THE VICINITY. IT IS POSSIBLE THAT A CELL
WILL MOVE OVER THE TERMINALS THROUGH THIS EVENING WITH REDUCED VIS
AND CIGS POSSIBLE IF THEY DO. KPUB WILL HAVE THE BEST CHANCE OF
SEEING THUNDERSTORMS THROUGH 02Z. MOZLEY
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH UNTIL 8 PM MDT THIS EVENING FOR COZ067-068.
&&
$$
SHORT TERM...MOZLEY
LONG TERM...LW
AVIATION...MOZLEY
AREA FORECAST DISCUSSION
NWS ALBANY NY
207 PM EDT THU AUG 1 2013
.SYNOPSIS...
UNSETTLED WEATHER RETURNS THIS AFTERNOON...AS A LOW
PRESSURE SYSTEM...AND ASSOCIATED FRONTAL BOUNDARIES APPROACH FROM
THE GREAT LAKES REGION AND MID ATLANTIC REGION. THIS WILL BRING
OCCASIONAL SHOWERS TO THE REGION FOR THIS AFTERNOON AND EVENING.
DRIER WEATHER IS EXPECTED ON FRIDAY AS A WEAK RIDGE OF HIGH PRESSURE
BUILDS INTO THE REGION.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 1230 PM EDT...THE LATEST REGIONAL MOSAIC RADAR AND SATELLITE
IMAGERY CONTINUED TO INDICATE AN INCREASE IN SHOWER ACTIVITY ACROSS
THE REGION...MAINLY FROM THE HUDSON VALLEY WEST AS ISENTROPIC LIFT
COMMENCES.
THERE WAS A BREAK IN THE SHOWERS ACROSS CENTRAL NY STATE BUT ANOTHER
LINE OF SHOWERS AND EVEN A FEW EMBEDDED THUNDERSTORMS WAS FORMING IN
WESTERN NY...ASSOCIATED WITH THE OCCLUDED FRONT.
TEMPERATURES WILL LIKELY NOT RISE MUCH IF AT ALL ACROSS THE REGION
AND IN SOME CASES MIGHT EVEN FALL A POINT OR TWO. THEY WILL TOP OUT
GENERALLY IN THE 70S.
THE LATEST HRRR 3-KM COLUMNAR REF PRODUCT AND THE LOCAL WRF CONTINUE
TO INDICATE SHOWERS ACROSS OUR REGION...PEAKING IN THE EARLY
AFTERNOON....THEN TAPERING FOR A BIT. BOTH MODELS DUE BRING THE LINE
OF SHOWERS OVER WESTERN NEW YORK ACROSS OUR REGION AROUND 8PM. ANY
OF THESE SHOWERS OR STORMS COULD BE LOCALLY AND BRIEFLY HEAVY...BUT
NOT ENOUGH TO INCLUDE IN THE ENHANCED WORDING.
IN ADDITION TO THE ISENTROPIC LIFT...STRONG A THETA E RIDGE BUILDS
ACROSS THE REGION H10-H8 WITH PWATS INCREASING TO ABOVE 1.5 INCHES.
HAVE CAT POPS ACROSS THE REGION THIS AFTERNOON.
FOR THIS UPDATE...JUST MINOR RE-TOOLING BUT DID RAISE DEWPOINTS A
BIT INTO THE 60S.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY NIGHT/...
FOR TONIGHT...HEAVIEST RAIN EXPECTED DURING THE FIRST HALF OF THE
NIGHT AS AXIS OF HIGH PWATS AND THETA E RIDGE SHIFTS EAST OF FA
AFT 06Z. HAVE ALSO PLACED SLIGHT CHANCE OF TSTMS IN GRIDS AS
SHOWALTER INDICES BRIEFLY GO NEGATIVE THIS EVENING DESPITE SB
CAPES ONLY REACHING A FEW HUNDRED J/KG. EXPECT LOWS TONIGHT TO
RANGE FROM THE MID 50S TO LOWER 60S.
FRIDAY AND FRIDAY NIGHT EXPECT GENERALLY DRY CONDITIONS AS A WEAK
RIDGE OF HIGH PRESSURE BUILDS INTO THE REGION ON FRIDAY AND SLIDES
EAST FRIDAY NIGHT. HAVE KEPT LOW CHANCE POPS ACROSS NORTHWEST THIRD
OF FA DURING THESE PERIODS AS CANNOT RULE OUT SOME SHOWERS OFF
EAST END OF LAKE ONTARIO INTO THIS AREA WITH FAIRLY GOOD COLD POOL
ALOFT. HIGHS ON FRIDAY ARE EXPECTED TO BE IN THE 70S TO LOWER 80S
WITH LOWS FRIDAY NIGHT IN THE 50S.
ON SATURDAY EXPECT SCATTERED SHOWERS AHEAD OF A SECOND COLD FRONT
WITH THE HIGHEST POPS ACROSS THE NORTHERN MOUNTAINS. SB CAPES ARE
FAIRLY LOW GENERALLY 200-500 J/KG WITH SHOWALTER INDICES REMAINING
POSITIVE THROUGHOUT SATURDAY AND SATURDAY NIGHT. SO WILL LEAVE ANY
MENTION OF THUNDER OUT AT THIS TIME. EXPECT HIGHS ON SATURDAY TO
BE IN THE 70S TO LOWER 80S WITH LOWS SATURDAY NIGHT RANGING FROM
THE UPPER 40S NORTHWEST TO UPPER 50S SOUTHEAST.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
THE EXTENDED FORECAST FEATURES A MEAN LONGWAVE TROUGH INFLUENCING
THE SENSIBLE OVER THE NORTHEAST. THE TROUGH WILL KEEP TEMPS SLIGHTLY
COOLER THAN NORMAL WITH INTERMITTENT DISTURBANCES IMPACTING NY AND
NEW ENGLAND IN THE W/NW FLOW ALOFT. THE 00Z/01 HPC GUIDANCE WAS
FOLLOWED CLOSELY.
SUNDAY-MONDAY NT...THE UPPER LEVEL TROUGH REMAINS QUITE AMPLIFIED
DURING THIS TIME FRAME...WITH EMBEDDED UPPER LEVEL IMPULSES DROPPING
SOUTHEAST INTO THE REGION. THESE OCCASIONAL BOUTS OF
SYNOPTIC/DYNAMICAL LIFT...COMBINED WITH ADDED LAKE MOISTURE...SHOULD
ALLOW FOR ISOLATED TO SCATTERED SHOWERS TO OCCUR SUNDAY...ESP IN THE
AFTERNOON...THEN AGAIN MONDAY...PARTICULARLY ACROSS THE SOUTHERN
ADIRONDACKS...SOUTHERN VT AND NW MA...WHERE LOW CHC POPS ARE
INDICATED...WITH SLIGHT CHC POPS EXTENDING FURTHER SOUTH. IT WILL BE
QUITE BREEZY SUNDAY GIVEN A FAIRLY TIGHT PRESSURE GRADIENT BETWEEN
THE LOW ACROSS SOUTHEAST CANADA...AND HIGH PRESSURE ACROSS THE GREAT
LAKES REGION. TEMPS WILL REMAIN BELOW NORMAL...WITH SUNDAY MAXES
GENERALLY ONLY IN THE LOWER/MID 70S IN VALLEYS FROM ALBANY N AND
W...AND 75-80 SOUTH OF ALBANY...WITH HIGHER ELEVATIONS ACROSS
THE SOUTHERN ADIRONDACKS AND WESTERN NEW ENGLAND ONLY REACHING THE
60S. FOR SUN NT/MON AM...EXPECT WIDESPREAD 40S ACROSS THE SOUTHERN
ADIRONDACKS AND WESTERN NEW ENGLAND...AND ALSO WITHIN PORTIONS OF
THE EASTERN CATSKILLS/SCHOHARIE VALLEY AND LAKE GEORGE/SARATOGA
REGION...WITH LOWER/MID 50S ELSEWHERE. ON MONDAY...MAXES MAY WARM
SLIGHTLY...WITH GENERALLY 75-80 IN VALLEYS...AND UPPER 60S TO LOWER
70S ACROSS HIGHER ELEVATIONS.
TUE-WED...MODELS DIFFER ON TIMING OF STRONGER UPPER LEVEL IMPULSES
APPROACHING FROM THE WEST...AND ALSO THE AMOUNT OF INCREASING LOW
LEVEL MOISTURE FROM THE SOUTHWEST. HOWEVER...GENERAL CONSENSUS AT
THIS TIME RANGE IS FOR AN INCREASED CHANCE FOR SHOWERS...WITH LOW
CHC POPS INDICATED. TEMPS ARE FORECAST TO REACH THE 70S IN
VALLEYS...AND 60S ACROSS HIGHER ELEVATIONS FOR MAXES...AND GENERALLY
50S TO LOWER 60S IN VALLEYS...AND LOWER 50S FOR HIGHER ELEVATIONS
FOR MINS. SHOULD SHOWERS OR A STEADIER RAINFALL OCCUR ON ANY OF
THESE DAYS...EVEN COOLER MAX TEMPS COULD OCCUR.
&&
.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
A LOW PRESSURE SYSTEM WILL MOVE SOUTH OF THE REGION THIS
AFTERNOON...WHILE ANOTHER ONE PASSES NORTH INTO SRN QUEBEC. THE
OCCLUDED BOUNDARY TO THIS SYSTEM WILL CONTINUE THE THREAT OF
SHOWERS...AND PERHAPS A FEW RUMBLES OF THUNDER INTO THIS EVENING.
HIGH PRESSURE WILL BRIEFLY BUILD IN TOMORROW.
CONDITIONS WILL CONTINUE TO LOWER INTO THE MVFR RANGE AT ALL THE
TAF SITES IN TERMS OF CIGS AND VSBYS THIS AFTERNOON. KPSF AND KPOU
HAVE ALREADY HAD MVFR CIGS...AND THIS SHOULD LAST INTO THE
EVENING. KALB AND KGFL WILL LIKELY LOWER IN THE NEXT FEW HOURS
WITH CIGS AND PERHAPS VSBYS. THE RAIN SHIELD IS A LITTLE SPOTTY
AND SHOULD FILL IN BY THE MID AFTERNOON SOUTH AND EAST OF THE
CAPITAL REGION. THERE MAYBE A FEW RUMBLES THUNDER THIS EVENING
WHEN THE OCCLUDED FRONT ARRIVES. THE PROBABILITY IS NOT HIGH
ENOUGH TO INCLUDE IN THE TAFS AT THIS TIME.
CIGS AND VSBYS WILL CONTINUE TO LOWER TO POTENTIALLY THE IFR RANGE
...AS THE AIR MASS MOISTENS...AND PERHAPS SOME HEAVIER SHOWERS IMPACT
THE SRN PORTION OF THE REGION /SOUTH AND EAST OF KALB/ SHORTLY
BEFORE OR JUST AFTER MIDNIGHT. THE LOW MVFR/IFR CIGS MAY CONTINUE
TO 11-13Z...BEFORE STRONGER MIXING KICKS IN BEHIND THE FRONT...AND
DRIER AIR FILTERS IN.
THE LATEST GUIDANCE SHOWS LESS OF A THREAT OF LLWS. IT HAS BEEN
REMOVED FROM THE TAFS...AS THE STRONGEST WINDS AT 2500 KFT AGL
WILL BE AROUND 30-35 KTS.
THE SOUTH WINDS AT 5-12 KTS WITH SOME GUSTS TO 20-25 KTS AT KALB
WILL PERSIST THIS AFTERNOON. THEY WILL SLOWLY VEER TO THE
SOUTHWEST TO WEST AT LESS THAN 10 KTS SHORTLY BEFORE MIDNIGHT. THE
WINDS WILL INCREASE FROM THE WEST TO NORTHWEST AT 5-10 KTS AFTER
12Z.
OUTLOOK...
FRIDAY NIGHT: HIGH OPERATIONAL IMPACT. LIKELY SHRA...SLIGHT CHC TSRA.
SATURDAY: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF SHRA.
SATURDAY NIGHT: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF SHRA.
SUNDAY: MODERATE OPERATIONAL IMPACT. CHANCE OF SHRA.
SUNDAY NIGHT: MODERATE OPERATIONAL IMPACT. CHANCE OF SHRA.
MONDAY: LOW OPERATIONAL IMPACT.BREEZY ISOLATED SHRA.
MONDAY NIGHT: NO OPERATIONAL IMPACT. NO SIG WX.
&&
.FIRE WEATHER...
NO FIRE WEATHER RELATED CONCERNS ARE EXPECTED AT THIS TIME.
UNSETTLED WEATHER RETURNS TODAY AS A LOW PRESSURE SYSTEM...AND
ASSOCIATED FRONTAL BOUNDARIES APPROACH FROM THE GREAT LAKES REGION
AND THE OHIO VALLEY. THIS WILL BRING WIDESPREAD SHOWERS TO THE
REGION FOR THIS AFTERNOON AND EVENING. DRIER WEATHER IS EXPECTED
ON FRIDAY AS A WEAK RIDGE OF HIGH PRESSURE BUILDS INTO THE REGION
WITH MORE SCATTERED SHOWERS EXPECTED OVER THE WEEKEND.
&&
.HYDROLOGY...
SOME LOCALLY HEAVY RAINFALL IS EXPECTED THIS AFTERNOON INTO THIS
EVENING WITH THE HEAVIEST AMOUNTS EXPECTED TO FALL ACROSS THE
EASTERN CATSKILLS AND SOUTHERN ADIRONDACKS. TOTAL RAINFALL AMOUNTS
ARE GENERALLY EXPECTED TO BE BETWEEN 0.75 AND 1.5 INCHES WITH
LOCALLY HIGHER AMOUNTS POSSIBLE IN WIDELY SCATTERED THUNDERSTORMS
THIS EVENING. WHILE THESE AMOUNTS WILL NOT BE ENOUGH TO PRODUCE
ANY WIDESPREAD FLOODING...PONDING OF WATER ON ROADWAYS AND
LOCALIZED FLOODING OF POORLY DRAINED LOW LYING AREAS IS POSSIBLE.
DRIER WEATHER IS EXPECTED ON FRIDAY AS A WEAK RIDGE OF HIGH
PRESSURE BUILDS INTO THE REGION. MORE UNSETTLED WEATHER IS
EXPECTED OVER THE WEEKEND WITH SCATTERED SHOWERS BOTH SATURDAY AND
SUNDAY.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED
AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE
ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...HWJIV/11/WASULA
NEAR TERM...HWJIV/WASULA
SHORT TERM...11
LONG TERM...KL
AVIATION...WASULA
FIRE WEATHER...11
HYDROLOGY...11/WASULA
AREA FORECAST DISCUSSION
NWS ALBANY NY
1230 PM EDT THU AUG 1 2013
.SYNOPSIS...
UNSETTLED WEATHER RETURNS THIS AFTERNOON...AS A LOW
PRESSURE SYSTEM...AND ASSOCIATED FRONTAL BOUNDARIES APPROACH FROM
THE GREAT LAKES REGION AND MID ATLANTIC REGION. THIS WILL BRING
OCCASIONAL SHOWERS TO THE REGION FOR THIS AFTERNOON AND EVENING.
DRIER WEATHER IS EXPECTED ON FRIDAY AS A WEAK RIDGE OF HIGH PRESSURE
BUILDS INTO THE REGION.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 1230 PM EDT...THE LATEST REGIONAL MOSAIC RADAR AND SATELLITE
IMAGERY CONTINUED TO INDICATE AN INCREASE IN SHOWER ACTIVITY ACROSS
THE REGION...MAINLY FROM THE HUDSON VALLEY WEST AS ISENTROPIC LIFT
COMMENCES.
THERE WAS A BREAK IN THE SHOWERS ACROSS CENTRAL NY STATE BUT ANOTHER
LINE OF SHOWERS AND EVEN A FEW EMBEDDED THUNDERSTORMS WAS FORMING IN
WESTERN NY...ASSOCIATED WITH THE OCCLUDED FRONT.
TEMPERATURES WILL LIKELY NOT RISE MUCH IF AT ALL ACROSS THE REGION
AND IN SOME CASES MIGHT EVEN FALL A POINT OR TWO. THEY WILL TOP OUT
GENERALLY IN THE 70S.
THE LATEST HRRR 3-KM COLUMNAR REF PRODUCT AND THE LOCAL WRF CONTINUE
TO INDICATE SHOWERS ACROSS OUR REGION...PEAKING IN THE EARLY
AFTERNOON....THEN TAPERING FOR A BIT. BOTH MODELS DUE BRING THE LINE
OF SHOWERS OVER WESTERN NEW YORK ACROSS OUR REGION AROUND 8PM. ANY
OF THESE SHOWERS OR STORMS COULD BE LOCALLY AND BRIEFLY HEAVY...BUT
NOT ENOUGH TO INCLUDE IN THE ENHANCED WORDING.
IN ADDITION TO THE ISENTROPIC LIFT...STRONG A THETA E RIDGE BUILDS
ACROSS THE REGION H10-H8 WITH PWATS INCREASING TO ABOVE 1.5 INCHES.
HAVE CAT POPS ACROSS THE REGION THIS AFTERNOON.
FOR THIS UPDATE...JUST MINOR RE-TOOLING BUT DID RAISE DEWPOINTS A
BIT INTO THE 60S.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY NIGHT/...
FOR TONIGHT...HEAVIEST RAIN EXPECTED DURING THE FIRST HALF OF THE
NIGHT AS AXIS OF HIGH PWATS AND THETA E RIDGE SHIFTS EAST OF FA
AFT 06Z. HAVE ALSO PLACED SLIGHT CHANCE OF TSTMS IN GRIDS AS
SHOWALTER INDICES BRIEFLY GO NEGATIVE THIS EVENING DESPITE SB
CAPES ONLY REACHING A FEW HUNDRED J/KG. EXPECT LOWS TONIGHT TO
RANGE FROM THE MID 50S TO LOWER 60S.
FRIDAY AND FRIDAY NIGHT EXPECT GENERALLY DRY CONDITIONS AS A WEAK
RIDGE OF HIGH PRESSURE BUILDS INTO THE REGION ON FRIDAY AND SLIDES
EAST FRIDAY NIGHT. HAVE KEPT LOW CHANCE POPS ACROSS NORTHWEST THIRD
OF FA DURING THESE PERIODS AS CANNOT RULE OUT SOME SHOWERS OFF
EAST END OF LAKE ONTARIO INTO THIS AREA WITH FAIRLY GOOD COLD POOL
ALOFT. HIGHS ON FRIDAY ARE EXPECTED TO BE IN THE 70S TO LOWER 80S
WITH LOWS FRIDAY NIGHT IN THE 50S.
ON SATURDAY EXPECT SCATTERED SHOWERS AHEAD OF A SECOND COLD FRONT
WITH THE HIGHEST POPS ACROSS THE NORTHERN MOUNTAINS. SB CAPES ARE
FAIRLY LOW GENERALLY 200-500 J/KG WITH SHOWALTER INDICES REMAINING
POSITIVE THROUGHOUT SATURDAY AND SATURDAY NIGHT. SO WILL LEAVE ANY
MENTION OF THUNDER OUT AT THIS TIME. EXPECT HIGHS ON SATURDAY TO
BE IN THE 70S TO LOWER 80S WITH LOWS SATURDAY NIGHT RANGING FROM
THE UPPER 40S NORTHWEST TO UPPER 50S SOUTHEAST.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
THE EXTENDED FORECAST FEATURES A MEAN LONGWAVE TROUGH INFLUENCING
THE SENSIBLE OVER THE NORTHEAST. THE TROUGH WILL KEEP TEMPS SLIGHTLY
COOLER THAN NORMAL WITH INTERMITTENT DISTURBANCES IMPACTING NY AND
NEW ENGLAND IN THE W/NW FLOW ALOFT. THE 00Z/01 HPC GUIDANCE WAS
FOLLOWED CLOSELY.
SUNDAY-MONDAY NT...THE UPPER LEVEL TROUGH REMAINS QUITE AMPLIFIED
DURING THIS TIME FRAME...WITH EMBEDDED UPPER LEVEL IMPULSES DROPPING
SOUTHEAST INTO THE REGION. THESE OCCASIONAL BOUTS OF
SYNOPTIC/DYNAMICAL LIFT...COMBINED WITH ADDED LAKE MOISTURE...SHOULD
ALLOW FOR ISOLATED TO SCATTERED SHOWERS TO OCCUR SUNDAY...ESP IN THE
AFTERNOON...THEN AGAIN MONDAY...PARTICULARLY ACROSS THE SOUTHERN
ADIRONDACKS...SOUTHERN VT AND NW MA...WHERE LOW CHC POPS ARE
INDICATED...WITH SLIGHT CHC POPS EXTENDING FURTHER SOUTH. IT WILL BE
QUITE BREEZY SUNDAY GIVEN A FAIRLY TIGHT PRESSURE GRADIENT BETWEEN
THE LOW ACROSS SOUTHEAST CANADA...AND HIGH PRESSURE ACROSS THE GREAT
LAKES REGION. TEMPS WILL REMAIN BELOW NORMAL...WITH SUNDAY MAXES
GENERALLY ONLY IN THE LOWER/MID 70S IN VALLEYS FROM ALBANY N AND
W...AND 75-80 SOUTH OF ALBANY...WITH HIGHER ELEVATIONS ACROSS
THE SOUTHERN ADIRONDACKS AND WESTERN NEW ENGLAND ONLY REACHING THE
60S. FOR SUN NT/MON AM...EXPECT WIDESPREAD 40S ACROSS THE SOUTHERN
ADIRONDACKS AND WESTERN NEW ENGLAND...AND ALSO WITHIN PORTIONS OF
THE EASTERN CATSKILLS/SCHOHARIE VALLEY AND LAKE GEORGE/SARATOGA
REGION...WITH LOWER/MID 50S ELSEWHERE. ON MONDAY...MAXES MAY WARM
SLIGHTLY...WITH GENERALLY 75-80 IN VALLEYS...AND UPPER 60S TO LOWER
70S ACROSS HIGHER ELEVATIONS.
TUE-WED...MODELS DIFFER ON TIMING OF STRONGER UPPER LEVEL IMPULSES
APPROACHING FROM THE WEST...AND ALSO THE AMOUNT OF INCREASING LOW
LEVEL MOISTURE FROM THE SOUTHWEST. HOWEVER...GENERAL CONSENSUS AT
THIS TIME RANGE IS FOR AN INCREASED CHANCE FOR SHOWERS...WITH LOW
CHC POPS INDICATED. TEMPS ARE FORECAST TO REACH THE 70S IN
VALLEYS...AND 60S ACROSS HIGHER ELEVATIONS FOR MAXES...AND GENERALLY
50S TO LOWER 60S IN VALLEYS...AND LOWER 50S FOR HIGHER ELEVATIONS
FOR MINS. SHOULD SHOWERS OR A STEADIER RAINFALL OCCUR ON ANY OF
THESE DAYS...EVEN COOLER MAX TEMPS COULD OCCUR.
&&
.AVIATION /16Z THURSDAY THROUGH MONDAY/...
AFTER ANY PATCHES OF MIST BURN OFF AND ASSOCIATED MVFR VSBYS AT KGFL
AND KPSF LIFT BTWN 12Z-14Z/THU...VFR CONDITIONS WILL THEN OCCUR FROM
SUNRISE THROUGH LATE MORNING...BEFORE LOWERING INTO THE MVFR RANGE
FOR VSBYS/CIGS AS SHOWERS OR A PERIOD OF STEADY RAIN OVERSPREADS THE
TAF SITES BETWEEN 16Z-18Z. SOME EMBEDDED PERIODS OF IFR CIGS/VSBYS
COULD OCCUR WITHIN ANY HEAVIER RAIN ELEMENTS...ESP AT KPSF AND KPOU
WHICH WILL BE CLOSER TO WARM RAIN PROCESSES AND POTENTIAL SMALLER
DROPLET SIZE AND LOWER CIGS. THE STEADIEST RAIN SHOULD PERSIST MOST
OF THE AFTERNOON.
THE RAIN AND/OR SHOWERS SHOULD BECOME MORE SCATTERED AFTER
23Z/THU...AND SHOULD TAPER OFF FROM W TO E BETWEEN 00Z-04Z/THU.
HOWEVER...VERY MOIST CONDITIONS BEHIND A WIND SHIFT SHOULD CREATE
WIDESPREAD LOW MVFR TO IFR CIGS/VSBYS...ESP AT KGFL/KPSF/KPOU.
THERE IS A SLIGHT CHANCE FOR EMBEDDED THUNDERSTORMS THIS AFTERNOON
AND EVENING...BUT OVERALL PROBABILITY FOR ANY IMPACTING A TAF SITE
WILL BE RATHER LOW...SO WILL KEEP OUT MENTION IN TAFS AT THIS TIME.
SOUTH WINDS WILL INCREASE AFTER 14Z/THU TO 8-12 KT...WITH SOME
GUSTINESS DEVELOPING...ESP AT KALB WHERE GUSTS OF 25 KT OR SLIGHTLY
HIGHER COULD OCCUR. SOUTH WINDS SHOULD DECREASE THIS EVENING INTO
THE OVERNIGHT HOURS TO 5-10 KT...WITH WINDS GRADUALLY VEERING INTO
THE SOUTHWEST TO WEST TOWARD OR AFTER 04Z/FRI.
LOW LEVEL WIND SHEAR WILL DEVELOP AT KGFL/KPOU AND KPSF THIS
AFTERNOON AS WINDS AROUND 2000 FT AGL INCREASE FROM THE SOUTH AT
30-35 KT...WHILE SFC WINDS REMAIN GENERALLY UNDER 12 KT. AT
KALB...ENOUGH MIXING SHOULD ALLOW STRONGER WINDS TO TRANSFER
DOWNWARD AT TIMES...REDUCING LOW LEVEL WIND SHEAR POTENTIAL.
OUTLOOK...
FRIDAY NIGHT: HIGH OPERATIONAL IMPACT. LIKELY SHRA...TSRA.
SATURDAY: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF SHRA.
SATURDAY NIGHT: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF SHRA.
SUNDAY: MODERATE OPERATIONAL IMPACT. CHANCE OF SHRA.
SUNDAY NIGHT: MODERATE OPERATIONAL IMPACT. CHANCE OF SHRA.
MONDAY: LOW OPERATIONAL IMPACT.BREEZY ISOLATED SHRA.
MONDAY NIGHT: NO OPERATIONAL IMPACT. NO SIG WX.
&&
.FIRE WEATHER...
NO FIRE WEATHER RELATED CONCERNS ARE EXPECTED AT THIS TIME.
UNSETTLED WEATHER RETURNS TODAY AS A LOW PRESSURE SYSTEM...AND
ASSOCIATED FRONTAL BOUNDARIES APPROACH FROM THE GREAT LAKES REGION
AND THE OHIO VALLEY. THIS WILL BRING WIDESPREAD SHOWERS TO THE
REGION FOR THIS AFTERNOON AND EVENING. DRIER WEATHER IS EXPECTED
ON FRIDAY AS A WEAK RIDGE OF HIGH PRESSURE BUILDS INTO THE REGION
WITH MORE SCATTERED SHOWERS EXPECTED OVER THE WEEKEND.
&&
.HYDROLOGY...
SOME LOCALLY HEAVY RAINFALL IS EXPECTED THIS AFTERNOON INTO THIS
EVENING WITH THE HEAVIEST AMOUNTS EXPECTED TO FALL ACROSS THE
EASTERN CATSKILLS AND SOUTHERN ADIRONDACKS. TOTAL RAINFALL AMOUNTS
ARE GENERALLY EXPECTED TO BE BETWEEN 0.75 AND 1.5 INCHES WITH
LOCALLY HIGHER AMOUNTS POSSIBLE IN WIDELY SCATTERED THUNDERSTORMS
THIS EVENING. WHILE THESE AMOUNTS WILL NOT BE ENOUGH TO PRODUCE
ANY WIDESPREAD FLOODING...PONDING OF WATER ON ROADWAYS AND
LOCALIZED FLOODING OF POORLY DRAINED LOW LYING AREAS IS POSSIBLE.
DRIER WEATHER IS EXPECTED ON FRIDAY AS A WEAK RIDGE OF HIGH
PRESSURE BUILDS INTO THE REGION. MORE UNSETTLED WEATHER IS
EXPECTED OVER THE WEEKEND WITH SCATTERED SHOWERS BOTH SATURDAY AND
SUNDAY.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED
AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE
ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...HWJIV/11/WASULA
NEAR TERM...HWJIV/WASULA
SHORT TERM...11
LONG TERM...KL
AVIATION...KL/WASULA
FIRE WEATHER...11
HYDROLOGY...11/WASULA
AREA FORECAST DISCUSSION
NWS TAUNTON MA
1023 AM EDT THU AUG 1 2013
.SYNOPSIS...
HIGH PRESSURE MOVES OFFSHORE TONIGHT PROVIDING A LIGHT SOUTH FLOW.
COLD FRONT OVER THE GREAT LAKES SWINGS EAST AND GENERATES SHOWERS
AND SCATTERED THUNDERSTORMS OVER NEW ENGLAND LATER THURSDAY AND
THURSDAY NIGHT. ASIDE FROM A FEW SPOTTY SHOWERS...DRY WEATHER IS
ON TAP FOR THE WEEKEND AND INTO NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
1015 AM UPDATE...
SHOWERS ADVANCING EWD FROM E PA AND NJ. THESE SHOWERS ARE ASSOCD
WITH A MODEST LOW LEVEL JET AND ACCOMPANYING MOISTURE TRANSPORT
WHICH MOVES INTO WESTERN NEW ENG 18-21Z THEN APPROACHES E NEW ENG
BY 00Z. SHOWERS WILL BE MOVING INTO WESTERN ZONES THIS
AFTERNOON WITH SCT ACTIVITY POSSIBLE IN EASTERN NEW ENG TOWARD
EVENING. THE HRRR SUGGESTS THE PRECIP MAY SPLIT LATER TODAY WITH
A CONCENTRATION TO THE N AND A SECOND AREA MOVING INTO CT FROM
THE S. AND THE NAM OMEGA FIELDS HINT AT THE SAME THING. HIGHEST
POPS THIS AFTERNOON WILL BE ACROSS W ZONES WITH POPS DECREASING
EWD. PWATS INCREASING TO 1.50-1.75" SO LOCALLY HEAVY RAINFALL
POSSIBLE IN THE WEST.
SBCAPES ARE MINIMAL TO NIL THROUGH TODAY...BUT GUIDANCE IS
INDICATING SOME ELEVATED INSTABILITY MOVING INTO W ZONES LATER
THIS AFTERNOON...SO WE HAVE A CHC THUNDER HERE.
SUNSHINE WILL GIVE WAY TO INCREASING CLOUDS FROM WEST TO EAST.
MADE NO CHANGES TO TEMPS...RANGING FROM MID/UPPER 70S WEST TO
LOWER 80S EAST.
PREVIOUS DISCUSSION...
01/00Z GUIDANCE IS IN EXCELLENT AGREEMENT WITH THEIR OVERALL
SYNOPTIC PATTERNS. AS SUCH...USED THE CONSENSUS TIMING AS A GUIDE.
DID SLOW THE ARRIVAL OF RAINFALL THIS MORNING BASED ON UPSTREAM
RADAR DATA AND EXPECTED TIMING OF SYNOPTIC FEATURES.
WATER VAPOR IMAGERY SHOWING A POTENT MID-LEVEL SHORTWAVE OVER THE
GREAT LAKES. THIS SHORTWAVE WILL BE ONE OF THE FEATURES ARRIVING
LATER TODAY TO CONTRIBUTE TO DEVELOPMENT OF SHOWERS AND
THUNDERSTORMS. STRONG UPPER LEVEL JET WILL PROVIDE PLENTY OF
VENTING LATE TODAY. CLOSER TO THE GROUND...EXPECTING EFFECTIVE
BULK SHEAR VALUES OF 25-30 KT. LOW-LEVEL LAPSE RATES ARE PROJECTED
TO BE NEAR MOIST ADIABATIC. AS SUCH...EXPECTING MORE SHOWERS THAN
THUNDERSTORMS. HOWEVER...THERE IS AT LEAST A POTENTIAL FOR
STRONGER TO POSSIBLE SEVERE THUNDERSTORMS. LATE TODAY.
THE BIGGER CONCERN WILL BE FOR LOCALLY HEAVY RAINFALL WITH
PRECIPITABLE WATER VALUES RISING INTO THE 1.5-2.0 INCH RANGE.
SHEAR VECTORS DO INDICATE STORMS SHOULD MOVE THIS AFTERNOON...SO
THE CONCERN WOULD BE PRIMARILY URBAN AND POOR-DRAINAGE AREAS.
SEASONABLE TEMPERATURES EXPECTED...AS REPRESENTED BY A BLEND OF
THE MOS GUIDANCE.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM FRIDAY/...
UPPER LOW OVER HUDSON BAY IS EXPECTED TO MOVE A NEGATIVELY-TILTED
TROUGH ACROSS SOUTHERN NEW ENGLAND TONIGHT. THIS WILL CONTRIBUTE
TO AN OVERALL SLOWING OF INDIVIDUAL CELL MOTION...FURTHER
ENHANCING THE RISK OF HEAVY RAINFALL. 01/00Z GUIDANCE IS QUITE
CONSISTENT MOVING THE STRONGEST OF THE FORCING MECHANISMS OFF THE
COAST SHORTLY AFTER MIDNIGHT. THAT SAID...THERE ARE STILL PLENTY
OF SYNOPTIC LIFTING MECHANISMS TO KEEP AT LEAST A CHANCE OF
SHOWERS IN THE FORECAST THROUGH MOST OF THE NIGHT. SHOWERS SHOULD
END FROM WEST TO EAST LATE TONIGHT INTO FRIDAY.
GRADUAL CLEARING FROM WEST TO EAST DURING THE DAY FRIDAY.
SEASONABLE TO SLIGHTLY ABOVE NORMAL TEMPERATURES. USED A BLEND OF
THE MOS GUIDANCE ONCE AGAIN.
&&
.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
HIGHLIGHTS...
* EXTENDED PERIOD OF MOSTLY DRY...SEASONABLE WEATHER
* FEW SHOWERS EXPECTED SUNDAY
* NEXT CHANCE OF WIDESPREAD RAIN TUE INTO WED
OVERVIEW AND MODEL PREFERENCES...
01/00Z MODEL GUIDANCE SUITE CONTINUES TO SHOW DECENT SYNOPTIC
SCALE AGREEMENT THROUGH THE MEDIUM RANGE BUT THEN STRUGGLE WITH A
SERIES OF CUTOFF LOW PRESSURES WHICH WILL FUJIWHARA THROUGH A
BROAD TROF IN ONTARIO AND QUEBEC. DESPITE THE SYNOPTIC AGREEMENT
IN THE MEDIUM RANGE...THERE ARE STILL SOME SMALLER SCALE ISSUES TO
RESOLVE REGARDING A SERIES OF SHORTWAVES WHICH WILL SLIDE THROUGH
THE BASE OF THE TROF AND INTO NEW ENGLAND THROUGH THE WEEKEND.
RECENT TREND IN GUIDANCE IS TO SUGGEST A HIGHER CHANCE FOR -SHRA
SAT AND SAT NIGHT AS INITIAL WAVE AND ATTENDANT COLD FRONT SLIDES
NEAR THE REGION. HOWEVER...THEY DISAGREE ON THE AXIS OF QPF...THE
NAM ON THE NRN EDGE OF THE SOLUTION ENVELOPE AND THE ECMWF ON THE
SRN END. FEEL THE MORE SRN SOLUTION IS BEST GIVEN THAT THERE IS A
SECOND AND STRONGER WAVE PROJECTED TO SLIDE THROUGH THE REGION ON
SUN. THEREFORE...WILL BE ERRING AWAY FROM THE NAM SOLUTION FOR
THIS UPDATE WITH A CONTINUED ECMWF/GFS DETERMINISTIC BLEND THROUGH
THE WEEKEND AND EARLY NEXT WEEK.
FOR THE TUE AND MID WEEK TIMEFRAME GUIDANCE CONTINUES TO STRUGGLE
BETWEEN A SERIES OF CUTOFF LOW PRESSURES MOVING THROUGH A BROAD
TROF IN ONTARIO AND QUEBEC...AND A BUILDING RIDGE OVER THE SRN
CONUS. THE RESULT IS A NEARLY ZONAL MEAN JET ACROSS NEW ENGLAND.
EXPECT A DRY HIGH PRES TO START...BUT THERE ARE SERIOUS TIMING AND
STRENGTH DIFFERENCES IN THE PASSAGE OF SHORTWAVES THROUGH THIS
JET. AM NOTING LOW AND MID LVL FLOW IS GENERALLY W TO NW THROUGH
MON THROUGH EARLY WED...SO A MAINLY DRY FORECAST LOOKS BEST...BUT
THEN WILL INCREASE TO SLIGHT/CHANCE POPS FOR THE WED- THU
TIMEFRAME DUE TO THE POTENTIAL PASSAGE OF A SERIES OF WAVES. AS
MENTIONED EARLIER THOUGH...THIS WILL LIKELY NOT BE A WASHOUT THE
ENTIRE TIME GIVEN THE DIFFICULTY GUIDANCE IS HAVING IN RESOLVING
THE SHORTWAVES.
DETAILS...
THIS WEEKEND...
BROAD TROUGH WITH AXIS THROUGH NEW ENGLAND WILL ALLOW FOR A
SERIES OF FAST MOVING SHORTWAVES AND THEIR ATTENDANT SFC FRONTS TO
CROSS THE REGION. WITH LESS OVERALL MOISTURE THANKS TO W LOW-MID
LVL FLOW...AND HIGH PRES ATTEMPTING TO RIDGE OVER THE REGION FROM
THE SW. EXPECTING ONLY -SHRA ACTIVITY WITH BEST CHANCES LATE DAY
SAT AND AGAIN LATE DAY SUN...DURING THE TIMING OF PEAK VORT MAX
PASSAGE. TEMPS WILL BE NEAR TO SLIGHTLY COOLER THAN NORMAL...WITH
LIKELY PARTLY TO MOSTLY CLOUDY SKIES.
MON INTO TUE...
HIGH PRES BEGINS TO BUILD OVER THE REGION FROM THE W DESPITE TROF
THROUGH NRN NEW ENGLAND AND SRN CANADA. THE COMBINATION OF W-NW
FLOW AND SUBSIDENCE SHOULD YIELD A MOSTLY DRY FORECAST. TEMPS
WILL LIKELY CONTINUE TO LEAN ON THE COOL SIDE OF NORMAL.
WED INTO THU...
WILL TRANSITION FROM DRY TO UNSETTLED AND POTENTIALLY WET FOR
THIS PORTION OF THE EXTENDED. NOT EXPECTING A WASHOUT...BUT THE
THREAT FOR SOME RAIN...AND POSSIBLY EVEN A FEW THUNDERSTORMS ARE
POSSIBLE GIVEN THE INITIAL RETURN FLOW. AS MENTIONED BY PREVIOUS
FORECASTER...WILL NEED TO WATCH THIS TIME PERIOD CLOSELY...BECAUSE
OF THE POTENTIAL CONVECTIVE NATURE OF THE PRECIPITATION.
&&
.AVIATION /14Z THURSDAY THROUGH MONDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
HIGH CONFIDENCE IN TAFS FOR MOST OF THE DAYLIGHT HOURS. MODERATE
CONFIDENCE IN TIMING OF LOWER CONDITIONS TONIGHT.
GENERALLY VFR THROUGH THE DAYLIGHT HOURS. LOOKS LIKE A MID
MORNING TO EARLY AFTERNOON SEA BREEZE IS LIKELY UNTIL WINDS SHIFT
MORE TO THE SOUTH. CLOUDS INCREASE THROUGH THE DAY. POTENTIAL FOR
SHOWERS/SCT TSTMS INCREASES THIS AFTERNOON AND EVENING...HIGHEST
VALUES WEST.
TONIGHT...MVFR/IFR CIGS/VSBYS IN SHOWERS AND SCATTERED TSTMS.
HEAVY DOWNPOURS LIKELY...AND AREAS OF FOG POSSIBLE. COLD FRONT
MOVES THROUGH LATE TONIGHT WITH WINDS SHIFTING TO NORTHWEST.
CIGS/VSBYS SHOULD IMPROVE WITH THE WIND SHIFT.
FRIDAY...MODERATE CONFIDENCE. MVFR/IFR CONDITIONS POSSIBLE IN
RAIN...MAINLY EASTERN MA EARLY. CONDITIONS IMPROVE TO VFR THROUGH
THE DAY.
KBOS TERMINAL...HIGH CONFIDENCE IN TAF...ESPECIALLY TRENDS. ANOTHER
SOUTHEAST SEABREEZE EXPECTED MID MORNING INTO THIS AFTERNOON.
SHOWERS APPROACH FROM THE WEST LATE IN THE DAY. TIMING OF LOWER
CONDITIONS MAY BE OFF BY A COUPLE OF HOURS EITHER SIDE OF 02/06Z.
KBDL TERMINAL...HIGH CONFIDENCE IN TAF. TIMING OF SHOWERS AND
LOWER CONDITIONS MAY BE OFF BY A COUPLE OF HOURS EITHER SIDE OF
02/00Z
OUTLOOK...FRIDAY NIGHT THROUGH MONDAY...
FRIDAY NIGHT THROUGH SUNDAY...MODERATE TO HIGH CONFIDENCE. MAINLY
VFR. LOW PROBABILITY OF BRIEF MVFR/IFR CONDITIONS IN ISOLATED TO
SCATTERED SHOWERS.
MONDAY...HIGH CONFIDENCE VFR.
&&
.MARINE...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
HIGH CONFIDENCE.
SOUTH TO SOUTHWEST WINDS INCREASE TODAY AHEAD OF A COLD FRONT. THE
MAIN IMPACT WILL BE TO GRADUALLY INCREASE SEAS ACROSS THE SOUTHERN
COASTAL WATERS. WHILE WINDS AND WIND GUSTS SHOULD REMAIN LESS
THAN 25 KT OUTSIDE OF THUNDERSTORMS...A SMALL CRAFT ADVISORY MAY
EVENTUALLY BE NEEDED FOR 5 FT SEAS FRIDAY. THE SOUTHERN OUTER
COASTAL WATERS WOULD BE MOST AT RISK.
OUTLOOK...FRIDAY NIGHT THROUGH MONDAY...
HIGH CONFIDENCE.
SEAS UP TO 5 FEET ON THE OUTER WATERS FRIDAY NIGHT INTO EARLY
SATURDAY WILL GRADUALLY DIMINISH AS HIGH PRESSURE BUILDS OVER THE
WATERS. WESTERLY WINDS WILL REMAIN BELOW 25 KTS FOR THE MOST PART.
&&
.CLIMATE...
THESE ARE THE LATEST STANDINGS FOR THE JULY AVERAGE TEMPERATURE.
ALL 4 OF THE MAJOR CLIMATE SITES FINISHED IN THE TOP 5.
BOSTON /LOGAN AIRPORT/
1. 78.0 IN 1983
2. 77.5 IN 1994 AND 1952
3. 77.3 IN 2011
4. 77.2 IN 2010 AND 1955
5. 77.1 IN 2013 AND 1911
PROVIDENCE /TF GREEN AIRPORT/
1. 78.4 IN 2013
2. 77.5 IN 2010
3. 76.6 IN 1983
4. 76.5 IN 1999
5. 76.4 IN 2008
HARTFORD/WINDSOR LOCKS /BRADLEY/
1. 77.9 IN 2013
2. 77.1 IN 2010 AND 1994
3. 77.0 IN 1955
4. 76.8 IN 1949
5. 76.5 IN 2006...1999 AND 1995
WORCESTER /AIRPORT/
1. 75.9 IN 1911
2. 74.3 IN 1952 AND 1901
3. 74.2 IN 1949
4. 74.1 IN 2013
5. 74.0 IN 2010
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...NONE.
NH...NONE.
RI...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...BELK/DOODY
NEAR TERM...BELK/KJC
SHORT TERM...BELK
LONG TERM...DOODY
AVIATION...BELK/DOODY
MARINE...BELK/DOODY
CLIMATE...
AREA FORECAST DISCUSSION
NWS ALBANY NY
1022 AM EDT THU AUG 1 2013
.SYNOPSIS...
UNSETTLED WEATHER RETURNS THIS AFTERNOON...AS A LOW
PRESSURE SYSTEM...AND ASSOCIATED FRONTAL BOUNDARIES APPROACH FROM
THE GREAT LAKES REGION AND MID ATLANTIC REGION. THIS WILL BRING
WIDESPREAD SHOWERS TO THE REGION FOR THIS AFTERNOON AND EVENING.
DRIER WEATHER IS EXPECTED ON FRIDAY AS A WEAK RIDGE OF HIGH PRESSURE
BUILDS INTO THE REGION.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 1015 PM EDT...THE LATEST REGIONAL MOSAIC RADAR AND SATELLITE
IMAGERY SHOWS THE CLOUDS AND SHOWERS HAVE INCREASED RAPIDLY OVER
CNTRL NY AND NE PA. THE CLOUDS HAVE OVERSPREAD ERN NY AND WRN NEW
ENGLAND WITH LITTLE ADDITIONAL HEATING EXPECTED. SOME MAX TEMPS
WERE ALREADY REACHED ACROSS PORTIONS OF SRN VT...AND ERN NY. SOME
SLIGHT ADJUSTMENTS UPWARD WERE MADE FOR A FEW MORE HOURS BEFORE
THE SHOWERS ARRIVE.
THE LATEST HRRR 3-KM COLUMNAR REF PRODUCT AND THE LOCAL WRF SHOWS
THE SHOWERS BECOMING MORE WIDESPREAD FROM SW TO NE OVER THE FCST
ARE BETWEEN NOON AND 3 PM. THE STEADIER SHOWERS SHOULD PERSIST INTO
THE EARLY EVENING...WHERE A FEW THUNDERSTORMS MAY POP UP NEAR THE
OCCLUDED FRONT TO CONNECTING THE CYCLONE NEAR THE ERN GREAT
LAKES...AND THE SFC WAVE OVER THE MID ATLANTIC REGION. ISENTROPIC
LIFT AHEAD OF THE BOUNDARY MAY YIELD POCKETS OF MODERATE TO HVY
RAINFALL. THE THE RIGHT REAR QUAD OF AN H250 JET STREAK WILL ALSO
ENHANCE THE RAIN A BIT.
IN ADDITION TO THE ISENTROPIC LIFT...STRONG A THETA E RIDGE BUILDS
ACRS THE REGION H10-H8 WITH PWATS INCREASING TO ABOVE 1.5 INCHES.
HAVE LIKELY TO CAT POPS ACRS THE REGION THIS AFTERNOON. THE TIMING
WAS TWEAKED SLIGHTLY. MAX TEMPS WILL RANGE FROM THE U60S TO M70S
ACROSS MOST OF THE REGION.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY NIGHT/...
FOR TONIGHT...HEAVIEST RAIN EXPECTED DURING THE FIRST HALF OF THE
NIGHT AS AXIS OF HIGH PWATS AND THETA E RIDGE SHIFTS EAST OF FA
AFT 06Z. HAVE ALSO PLACED SLIGHT CHANCE OF TSTMS IN GRIDS AS
SHOWALTER INDICES BRIEFLY GO NEGATIVE THIS EVENING DESPITE SB
CAPES ONLY REACHING A FEW HUNDRED J/KG. EXPECT LOWS TONIGHT TO
RANGE FROM THE MID 50S TO LOWER 60S.
FRIDAY AND FRIDAY NIGHT EXPECT GENERALLY DRY CONDITIONS AS A WEAK
RIDGE OF HIGH PRESSURE BUILDS INTO THE REGION ON FRIDAY AND SLIDES
EAST FRIDAY NIGHT. HAVE KEPT LOW CHANCE POPS ACRS NORTHWEST THIRD
OF FA DURING THESE PERIODS AS CANNOT RULE OUT SOME SHOWERS OFF
EAST END OF LAKE ONTARIO INTO THIS AREA WITH FAIRLY GOOD COLD POOL
ALOFT. HIGHS ON FRIDAY ARE EXPECTED TO BE IN THE 70S TO LOWER 80S
WITH LOWS FRIDAY NIGHT IN THE 50S.
ON SATURDAY EXPECT SCATTERED SHOWERS AHEAD OF A SECOND COLD FRONT
WITH THE HIGHEST POPS ACROSS THE NORTHERN MOUNTAINS. SB CAPES ARE
FAIRLY LOW GENERALLY 200-500 J/KG WITH SHOWALTER INDICES REMAINING
POSITIVE THROUGHOUT SATURDAY AND SATURDAY NIGHT. SO WILL LEAVE ANY
MENTION OF THUNDER OUT AT THIS TIME. EXPECT HIGHS ON SATURDAY TO
BE IN THE 70S TO LOWER 80S WITH LOWS SATURDAY NIGHT RANGING FROM
THE UPPER 40S NORTHWEST TO UPPER 50S SOUTHEAST.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
THE EXTENDED FORECAST FEATURES A MEAN LONGWAVE TROUGH INFLUENCING
THE SENSIBLE OVER THE NORTHEAST. THE TROUGH WILL KEEP TEMPS SLIGHTLY
COOLER THAN NORMAL WITH INTERMITTENT DISTURBANCES IMPACTING NY AND
NEW ENGLAND IN THE W/NW FLOW ALOFT. THE 00Z/01 HPC GUIDANCE WAS
FOLLOWED CLOSELY.
SUNDAY-MONDAY NT...THE UPPER LEVEL TROUGH REMAINS QUITE AMPLIFIED
DURING THIS TIME FRAME...WITH EMBEDDED UPPER LEVEL IMPULSES DROPPING
SOUTHEAST INTO THE REGION. THESE OCCASIONAL BOUTS OF
SYNOPTIC/DYNAMICAL LIFT...COMBINED WITH ADDED LAKE MOISTURE...SHOULD
ALLOW FOR ISOLATED TO SCATTERED SHOWERS TO OCCUR SUNDAY...ESP IN THE
AFTERNOON...THEN AGAIN MONDAY...PARTICULARLY ACROSS THE SOUTHERN
ADIRONDACKS...SOUTHERN VT AND NW MA...WHERE LOW CHC POPS ARE
INDICATED...WITH SLIGHT CHC POPS EXTENDING FURTHER SOUTH. IT WILL BE
QUITE BREEZY SUNDAY GIVEN A FAIRLY TIGHT PRESSURE GRADIENT BETWEEN
THE LOW ACROSS SOUTHEAST CANADA...AND HIGH PRESSURE ACROSS THE GREAT
LAKES REGION. TEMPS WILL REMAIN BELOW NORMAL...WITH SUNDAY MAXES
GENERALLY ONLY IN THE LOWER/MID 70S IN VALLEYS FROM ALBANY N AND
W...AND 75-80 SOUTH OF ALBANY...WITH HIGHER ELEVATIONS ACROSS
THE SOUTHERN ADIRONDACKS AND WESTERN NEW ENGLAND ONLY REACHING THE
60S. FOR SUN NT/MON AM...EXPECT WIDESPREAD 40S ACROSS THE SOUTHERN
ADIRONDACKS AND WESTERN NEW ENGLAND...AND ALSO WITHIN PORTIONS OF
THE EASTERN CATSKILLS/SCHOHARIE VALLEY AND LAKE GEORGE/SARATOGA
REGION...WITH LOWER/MID 50S ELSEWHERE. ON MONDAY...MAXES MAY WARM
SLIGHTLY...WITH GENERALLY 75-80 IN VALLEYS...AND UPPER 60S TO LOWER
70S ACROSS HIGHER ELEVATIONS.
TUE-WED...MODELS DIFFER ON TIMING OF STRONGER UPPER LEVEL IMPULSES
APPROACHING FROM THE WEST...AND ALSO THE AMOUNT OF INCREASING LOW
LEVEL MOISTURE FROM THE SOUTHWEST. HOWEVER...GENERAL CONSENSUS AT
THIS TIME RANGE IS FOR AN INCREASED CHANCE FOR SHOWERS...WITH LOW
CHC POPS INDICATED. TEMPS ARE FORECAST TO REACH THE 70S IN
VALLEYS...AND 60S ACROSS HIGHER ELEVATIONS FOR MAXES...AND GENERALLY
50S TO LOWER 60S IN VALLEYS...AND LOWER 50S FOR HIGHER ELEVATIONS
FOR MINS. SHOULD SHOWERS OR A STEADIER RAINFALL OCCUR ON ANY OF
THESE DAYS...EVEN COOLER MAX TEMPS COULD OCCUR.
&&
.AVIATION /14Z THURSDAY THROUGH MONDAY/...
AFTER ANY PATCHES OF MIST BURN OFF AND ASSOCIATED MVFR VSBYS AT KGFL
AND KPSF LIFT BTWN 12Z-14Z/THU...VFR CONDITIONS WILL THEN OCCUR FROM
SUNRISE THROUGH LATE MORNING...BEFORE LOWERING INTO THE MVFR RANGE
FOR VSBYS/CIGS AS SHOWERS OR A PERIOD OF STEADY RAIN OVERSPREADS THE
TAF SITES BETWEEN 16Z-18Z. SOME EMBEDDED PERIODS OF IFR CIGS/VSBYS
COULD OCCUR WITHIN ANY HEAVIER RAIN ELEMENTS...ESP AT KPSF AND KPOU
WHICH WILL BE CLOSER TO WARM RAIN PROCESSES AND POTENTIAL SMALLER
DROPLET SIZE AND LOWER CIGS. THE STEADIEST RAIN SHOULD PERSIST MOST
OF THE AFTERNOON.
THE RAIN AND/OR SHOWERS SHOULD BECOME MORE SCATTERED AFTER
23Z/THU...AND SHOULD TAPER OFF FROM W TO E BETWEEN 00Z-04Z/THU.
HOWEVER...VERY MOIST CONDITIONS BEHIND A WIND SHIFT SHOULD CREATE
WIDESPREAD LOW MVFR TO IFR CIGS/VSBYS...ESP AT KGFL/KPSF/KPOU.
THERE IS A SLIGHT CHANCE FOR EMBEDDED THUNDERSTORMS THIS AFTERNOON
AND EVENING...BUT OVERALL PROBABILITY FOR ANY IMPACTING A TAF SITE
WILL BE RATHER LOW...SO WILL KEEP OUT MENTION IN TAFS AT THIS TIME.
SOUTH WINDS WILL INCREASE AFTER 14Z/THU TO 8-12 KT...WITH SOME
GUSTINESS DEVELOPING...ESP AT KALB WHERE GUSTS OF 25 KT OR SLIGHTLY
HIGHER COULD OCCUR. SOUTH WINDS SHOULD DECREASE THIS EVENING INTO
THE OVERNIGHT HOURS TO 5-10 KT...WITH WINDS GRADUALLY VEERING INTO
THE SOUTHWEST TO WEST TOWARD OR AFTER 04Z/FRI.
LOW LEVEL WIND SHEAR WILL DEVELOP AT KGFL/KPOU AND KPSF THIS
AFTERNOON AS WINDS AROUND 2000 FT AGL INCREASE FROM THE SOUTH AT
30-35 KT...WHILE SFC WINDS REMAIN GENERALLY UNDER 12 KT. AT
KALB...ENOUGH MIXING SHOULD ALLOW STRONGER WINDS TO TRANSFER
DOWNWARD AT TIMES...REDUCING LOW LEVEL WIND SHEAR POTENTIAL.
OUTLOOK...
FRIDAY NIGHT: HIGH OPERATIONAL IMPACT. LIKELY SHRA...TSRA.
SATURDAY: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF SHRA.
SATURDAY NIGHT: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF SHRA.
SUNDAY: MODERATE OPERATIONAL IMPACT. CHANCE OF SHRA.
SUNDAY NIGHT: MODERATE OPERATIONAL IMPACT. CHANCE OF SHRA.
MONDAY: LOW OPERATIONAL IMPACT.BREEZY ISOLATED SHRA.
MONDAY NIGHT: NO OPERATIONAL IMPACT. NO SIG WX.
&&
.FIRE WEATHER...
NO FIRE WEATHER RELATED CONCERNS ARE EXPECTED AT THIS TIME.
UNSETTLED WEATHER RETURNS TODAY AS A LOW PRESSURE SYSTEM...AND
ASSOCIATED FRONTAL BOUNDARIES APPROACH FROM THE GREAT LAKES REGION
AND THE OHIO VALLEY. THIS WILL BRING WIDESPREAD SHOWERS TO THE
REGION FOR THIS AFTERNOON AND EVENING. DRIER WEATHER IS EXPECTED
ON FRIDAY AS A WEAK RIDGE OF HIGH PRESSURE BUILDS INTO THE REGION
WITH MORE SCATTERED SHOWERS EXPECTED OVER THE WEEKEND.
&&
.HYDROLOGY...
SOME LOCALLY HEAVY RAINFALL IS EXPECTED THIS AFTERNOON INTO THIS
EVENING WITH THE HEAVIEST AMOUNTS EXPECTED TO FALL ACROSS THE
EASTERN CATSKILLS AND SOUTHERN ADIRONDACKS. TOTAL RAINFALL AMOUNTS
ARE GENERALLY EXPECTED TO BE BETWEEN 0.75 AND 1.5 INCHES WITH
LOCALLY HIGHER AMOUNTS POSSIBLE IN WIDELY SCATTERED THUNDERSTORMS
THIS EVENING. WHILE THESE AMOUNTS WILL NOT BE ENOUGH TO PRODUCE
ANY WIDESPREAD FLOODING...PONDING OF WATER ON ROADWAYS AND
LOCALIZED FLOODING OF POORLY DRAINED LOW LYING AREAS IS POSSIBLE.
DRIER WEATHER IS EXPECTED ON FRIDAY AS A WEAK RIDGE OF HIGH
PRESSURE BUILDS INTO THE REGION. MORE UNSETTLED WEATHER IS
EXPECTED OVER THE WEEKEND WITH SCATTERED SHOWERS BOTH SATURDAY AND
SUNDAY.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED
AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE
ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...11/WASULA
NEAR TERM...11/WASULA
SHORT TERM...11
LONG TERM...KL
AVIATION...KL/WASULA
FIRE WEATHER...11
HYDROLOGY...11/WASULA
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
625 PM EDT THU AUG 1 2013
.SYNOPSIS...
A COLD FRONT...ATTACHED TO LOW PRESSURE OVER CANADA...WILL CROSS THE
AREA TONIGHT. HIGH PRESSURE FROM THE MIDWEST WILL THEN BUILD IN AND
AFFECT OUR WEATHER FRIDAY. ANOTHER COLD FRONT FROM CANADA WILL
ARRIVE OVER OUR AREA LATER SATURDAY AND MOVE AWAY BY SUNDAY. HIGH
PRESSURE WILL BUILD IN FOR SUNDAY AND PERSIST INTO EARLY NEXT WEEK.
A PAIR OF FRONTAL SYSTEMS SHOULD THEN MOVE THROUGH THE AREA TUESDAY
AND WEDNESDAY.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
THE LATEST RADAR IMAGERY SHOWED...NOT MUCH! THERE WERE SOME
THUNDERSTORMS TRYING TO GET A LITTLE MORE ORGANIZED IN LANCASTER
AND YORK COUNTIES BUT HAVE BEEN STRUGGLING AND THERE HAS BEEN A
PERSISTENT AREA OF SHOWERS AND STORMS ALONG THE LOWER DELMARVA
INTO EXTREME SRN DE. THERE ARE ALSO TSTMS NR WASHINGTON DC, BUT
ACRS OUR CWA THERE ARE SOME SCT SHWRS AND THAT`S ABOUT IT.
IT REMAINS TO BE SEEN IF ANY OF THE ACTIVITY TO OUR W WILL HOLD
TOGETHER TO IMPACT OUR AREA. THE HRRR DOES SHOW THAT AT LEAST SOME
SHOWERS WILL CROSS THE REGION. HAVE TRIMMED POPS BACK SOMEWHAT,
AND CONTINUED THE DOWNWARD TREND AS THE NIGHT PROGRESSES.
DUE TO THE LACK OF ORGANIZED ACTIVITY, HAVE OPTED TO DROP THE
FLASH FLOOD WATCH WITH THIS UPDATE. THERE STILL COULD BE SOME HEAVY
SHOWERS, BUT ANY FLOODING SHOULD BE LOCALIZED AND BRIEF.
THE COLD FRONT IS FORECAST TO CLEAR THE AREA LATER TONIGHT, WITH THE
SHOWERS/THUNDER ENDING BY 06Z. AS A RESULT, THE POPS ARE LOWERED A
BIT FASTER THAN PREVIOUSLY. THE FLOW WILL TURN WEST-NORTHWEST IN THE
WAKE OF THE COLD FRONT WITH SOME DRIER AIR WORKING IN. THE LOW-LEVEL
MOISTURE WILL TEND TO HOLD THE LONGEST ACROSS THE EASTERN AND
SOUTHERN ZONES, AND THEREFORE AS CLEARING OCCURS LATER THERE COULD
BE SOME LOCAL FOG.
AS FOR LOW TEMPERATURES, WE USED A GFS/NAM MOS BLEND WITH SOME MINOR
ADJUSTMENTS. THE LAMP/LAV GUIDANCE WAS USED TO ASSIST IN TRENDS THUS
FAR, AND HIGHS FOR THE REMAINDER OF THE AFTERNOON WERE LOWERED SOME.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH 6 PM FRIDAY/...
OUR WEATHER WILL BE DOMINATED BY AN UPPER-LEVEL TROUGH ACROSS THE
NORTHEAST, HOWEVER WEAK HIGH PRESSURE WILL BE BUILDING TO OUR
SOUTHWEST AND SOUTH. A COLD FRONT IS FORECAST TO BE TO OUR EAST TO
START THE DAY, WITH SOME DRYING CONTINUING TO WORK ITS WAY IN. THE
FORECAST SOUNDINGS SHOW THE DRYING NICELY, HOWEVER AS THE BOUNDARY
LAYER WARMS IT APPEARS WE ARE ABLE TO REACH THE CONVECTIVE
TEMPERATURES. AS A RESULT, SOME CUMULUS/STRATOCUMULUS SHOULD DEVELOP
FROM ABOUT MIDDAY ON. THERE MAY BE SOME MORE CLOUDS ACROSS THE FAR
NORTH IN THE AFTERNOON AS SHORT WAVE ENERGY GLANCES THAT AREA WITH
PERHAPS AN ISOLATED SHOWER. ELSEWHERE, NO SHOWERS ARE FORECAST ATTM
AS A CAP IS INDICATED TO DEVELOP DURING THE AFTERNOON.
THE HEATING OF THE BOUNDARY LAYER ALONG WITH SOME TIGHTENING OF THE
PRESSURE GRADIENT WILL ALLOW THE WINDS TO INCREASE SOME, AS THE
VERTICAL MIXING DEEPENS. WE DID INCREASE THE WINDS A BIT FROM
CONTINUITY. AS FOR HIGH TEMPERATURES, WE WENT WITH AN EVEN GFS/NAM
MOS BLEND THEN MADE SOME TWEAKS. GIVEN MORE SUNSHINE EXPECTED AND A
WESTERLY FLOW, TEMPERATURES ARE FORECAST TO BE WARMER COMPARED TO
TODAY.
&&
.LONG TERM /FRIDAY NIGHT THROUGH THURSDAY/...
A MEAN UPPER TROUGH WILL BE ACROSS THE MIDDLE ATLANTIC REGION DURING
MUCH OF THE LONG TERM PART OF THE FORECAST. THIS WILL PREVENT ANY
EXCESSIVE HEAT FROM BUILDING ACROSS THE AREA. IT WILL
PROMOTE...HOWEVER...RATHER QUICK CHANGES TO THE WEATHER WITH SEVERAL
SYSTEM SLATED TO AFFECT THE AREA THIS WEEKEND AND INTO THE MIDDLE OF
NEXT WEEK.
HIGH PRESSURE WILL BE ACROSS THE AREA FRIDAY NIGHT AND THE FIRST
PART OF SATURDAY...DRY WEATHER WITH MOSTLY SEASONABLE TEMPERATURES
EXPECTED. SATURDAY AND SATURDAY NIGHT WILL SEE AN INCREASING CHC FOR
SHOWERS AS ANOTHER COLD FRONT MOVES DOWN FROM THE NORTH AND CROSSES
THE AREA. THE SHOWERS SHOULD END ACROSS THE AREA SUNDAY MORNING WITH
ONLY SMALL TOTALS EXPECTED SUNDAY.
SEVERAL DRY DAYS ARE EXPECTED FROM LATER SUNDAY INTO MONDAY NIGHT AS
HIGH PRESSURE BUILDS BACK ACROSS THE REGION. TEMPERATURES DURING
THIS PERIOD WILL BE A FEW DEGREES BELOW NORMAL WITH HIGHS MOSTLY IN
THE LOW 80S (CENTRAL/SOUTH) AND MID TO UPPER 70S (NORTH). LOWS WILL
MOSTLY BE IN THE 50S NORTH/WEST AND LOW 60S SOUTH/EAST.
THE RETURN FLOW BEHIND THE DEPARTING HIGH WILL BRING INCREASED
MOISTURE AND BETTER CHC FOR SHOWERS FROM NEXT TUE INTO WED. WE
GENERALLY WENT ALONG WITH HPC POPS WITH ONLY MINOR CHANGES.
TEMPERATURES WILL BE WITHIN A FEW DEGREES OF NORMAL.
&&
.AVIATION /00Z FRIDAY THROUGH TUESDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.
CONDS RANGED FROM VFR TO IFR ACRS THE REGION, WITH THE LOWEST CIGS
RIGHT NOW ACRS THE I-95 CORRIDOR. EXPECT THE LWR (HOPEFULLY MVFR)
CIGS TO CONTINUE THRU THE EVENING UNTIL FROPA AND THEN AS THE WIND
BECOMES MORE WLY AND DRIER AIR MOVES IN, THE CIGS WILL IMPROVE TO
VFR. THIS COULD END UP HAPPENING SOONER THEN EXPECTED, OR LATER.
THERE ARE SOME TSRA OUT TWD LANCASTER AND WHILE ALL TSRA WAS
REMOVED FROM THE TAFS DUE TO THE ISOLD NATURE, THEY CAN NOT BE
RULED OUT, AT LEAST FOR THE NEXT FEW HOURS AND WILL BE HANDLED
WITH AMDTS IF THEY WERE TO OCCUR.
FRIDAY...VFR WITH SOME CLOUD BASES AROUND 5,000 FEET. WESTERLY WINDS
AROUND 10 KNOTS. HOWEVER, SOME GUSTS UP TO 20 KNOTS ARE ANTICIPATED
AS THE VERTICAL MIXING DEEPENS ESPECIALLY FROM MIDDAY ON.
OUTLOOK...
FRI NIGHT THRU SAT AFTERNOON...MOSTLY VFR.
SAT AFTERNOON THRU SUN MORNING...SCATTERED SHOWERS/TSTMS WITH
LOWER CONDITIONS POSSIBLE.
SUN AFTERNOON THRU TUESDAY...MOSTLY VFR. MORNING FOG POSSIBLE.
&&
.MARINE...
A SOUTHERLY FLOW WILL CONTINUE AHEAD OF A COLD FRONT. A WEAK SURFACE
LOW WILL MOVE ACROSS THE AREA THIS EVENING, FOLLOWED BY A COLD FRONT
LATER TONIGHT. THE SOUTHERLY FLOW HAS INCREASED WITH SOME GUSTS UP
TO 20 KNOTS. THIS IS EXPECTED TO CONTINUE FOR A TIME TONIGHT, THEN A
WIND SHIFT TO THE WEST LATE. A WESTERLY FLOW IS FORECAST FOR FRIDAY,
HOWEVER IT WILL BE LESS THAN 20 KNOTS. THE FLOW MAY ACTUALLY BACK A
BIT TO THE SOUTHWEST IN THE AFTERNOON GIVEN BETTER BOUNDARY LAYER
HEATING. SEAS HAVE BEEN SLOWLY BUILDING THIS AFTERNOON, AND WHILE
THEY COULD TOUCH 5 FEET ON THE OCEAN FOR A TIME WE BELIEVE THIS IS
MARGINAL AND MAY NOT LAST LONG. THEREFORE, WE WILL HOLD WITH NO
SMALL CRAFT ADVISORY ATTM. THE SEAS WILL LOWER SOME LATE AND ON
FRIDAY AS THE FLOW TURNS OFFSHORE FOR A TIME.
OUTLOOK...
SUB-SCA CONDITIONS EXPECTED ON THE WATERS THROUGH THE WEEKEND AND
EARLY NEXT WEEK. POSSIBLE SCA SEAS NEXT TUESDAY.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...O`HARA
NEAR TERM...GORSE/NIERENBERG
SHORT TERM...GORSE
LONG TERM...O`HARA
AVIATION...GORSE/NIERENBERG/O`HARA
MARINE...GORSE/O`HARA
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
620 PM EDT THU AUG 1 2013
.SYNOPSIS...
A COLD FRONT...ATTACHED TO LOW PRESSURE OVER CANADA...WILL CROSS THE
AREA TONIGHT. HIGH PRESSURE FROM THE MIDWEST WILL THEN BUILD IN AND
AFFECT OUR WEATHER FRIDAY. ANOTHER COLD FRONT FROM CANADA WILL
ARRIVE OVER OUR AREA LATER SATURDAY AND MOVE AWAY BY SUNDAY. HIGH
PRESSURE WILL BUILD IN FOR SUNDAY AND PERSIST INTO EARLY NEXT WEEK.
A PAIR OF FRONTAL SYSTEMS SHOULD THEN MOVE THROUGH THE AREA TUESDAY
AND WEDNESDAY.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
THE LATEST RADAR IMAGERY SHOWED...NOT MUCH! THERE WERE SOME
THUNDERSTORMS TRYING TO GET A LITTLE MORE ORGANIZED IN LANCASTER
AND YORK COUNTIES BUT HAVE BEEN STRUGGLING AND THERE HAS BEEN A
PERSISTENT AREA OF SHOWERS AND STORMS ALONG THE LOWER DELMARVA
INTO EXTREME SRN DE. THERE ARE ALSO TSTMS NR WASHINGTON DC, BUT
ACRS OUR CWA THERE ARE SOME SCT SHWRS AND THAT`S ABOUT IT.
IT REMAINS TO BE SEEN IF ANY OF THE ACTIVITY TO OUR W WILL HOLD
TOGETHER TO IMPACT OUR AREA. THE HRRR DOES SHOW THAT AT LEAST SOME
SHOWERS WILL CROSS THE REGION. HAVE TRIMMED POPS BACK SOMEWHAT,
AND CONTINUED THE DOWNWARD TREND AS THE NIGHT PROGRESSES.
THE COLD FRONT IS FORECAST TO CLEAR THE AREA LATER TONIGHT, WITH THE
SHOWERS/THUNDER ENDING BY 06Z. AS A RESULT, THE POPS ARE LOWERED A
BIT FASTER THAN PREVIOUSLY. THE FLOW WILL TURN WEST-NORTHWEST IN THE
WAKE OF THE COLD FRONT WITH SOME DRIER AIR WORKING IN. THE LOW-LEVEL
MOISTURE WILL TEND TO HOLD THE LONGEST ACROSS THE EASTERN AND
SOUTHERN ZONES, AND THEREFORE AS CLEARING OCCURS LATER THERE COULD
BE SOME LOCAL FOG.
AS FOR LOW TEMPERATURES, WE USED A GFS/NAM MOS BLEND WITH SOME MINOR
ADJUSTMENTS. THE LAMP/LAV GUIDANCE WAS USED TO ASSIST IN TRENDS THUS
FAR, AND HIGHS FOR THE REMAINDER OF THE AFTERNOON WERE LOWERED SOME.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH 6 PM FRIDAY/...
OUR WEATHER WILL BE DOMINATED BY AN UPPER-LEVEL TROUGH ACROSS THE
NORTHEAST, HOWEVER WEAK HIGH PRESSURE WILL BE BUILDING TO OUR
SOUTHWEST AND SOUTH. A COLD FRONT IS FORECAST TO BE TO OUR EAST TO
START THE DAY, WITH SOME DRYING CONTINUING TO WORK ITS WAY IN. THE
FORECAST SOUNDINGS SHOW THE DRYING NICELY, HOWEVER AS THE BOUNDARY
LAYER WARMS IT APPEARS WE ARE ABLE TO REACH THE CONVECTIVE
TEMPERATURES. AS A RESULT, SOME CUMULUS/STRATOCUMULUS SHOULD DEVELOP
FROM ABOUT MIDDAY ON. THERE MAY BE SOME MORE CLOUDS ACROSS THE FAR
NORTH IN THE AFTERNOON AS SHORT WAVE ENERGY GLANCES THAT AREA WITH
PERHAPS AN ISOLATED SHOWER. ELSEWHERE, NO SHOWERS ARE FORECAST ATTM
AS A CAP IS INDICATED TO DEVELOP DURING THE AFTERNOON.
THE HEATING OF THE BOUNDARY LAYER ALONG WITH SOME TIGHTENING OF THE
PRESSURE GRADIENT WILL ALLOW THE WINDS TO INCREASE SOME, AS THE
VERTICAL MIXING DEEPENS. WE DID INCREASE THE WINDS A BIT FROM
CONTINUITY. AS FOR HIGH TEMPERATURES, WE WENT WITH AN EVEN GFS/NAM
MOS BLEND THEN MADE SOME TWEAKS. GIVEN MORE SUNSHINE EXPECTED AND A
WESTERLY FLOW, TEMPERATURES ARE FORECAST TO BE WARMER COMPARED TO
TODAY.
&&
.LONG TERM /FRIDAY NIGHT THROUGH THURSDAY/...
A MEAN UPPER TROUGH WILL BE ACROSS THE MIDDLE ATLANTIC REGION DURING
MUCH OF THE LONG TERM PART OF THE FORECAST. THIS WILL PREVENT ANY
EXCESSIVE HEAT FROM BUILDING ACROSS THE AREA. IT WILL
PROMOTE...HOWEVER...RATHER QUICK CHANGES TO THE WEATHER WITH SEVERAL
SYSTEM SLATED TO AFFECT THE AREA THIS WEEKEND AND INTO THE MIDDLE OF
NEXT WEEK.
HIGH PRESSURE WILL BE ACROSS THE AREA FRIDAY NIGHT AND THE FIRST
PART OF SATURDAY...DRY WEATHER WITH MOSTLY SEASONABLE TEMPERATURES
EXPECTED. SATURDAY AND SATURDAY NIGHT WILL SEE AN INCREASING CHC FOR
SHOWERS AS ANOTHER COLD FRONT MOVES DOWN FROM THE NORTH AND CROSSES
THE AREA. THE SHOWERS SHOULD END ACROSS THE AREA SUNDAY MORNING WITH
ONLY SMALL TOTALS EXPECTED SUNDAY.
SEVERAL DRY DAYS ARE EXPECTED FROM LATER SUNDAY INTO MONDAY NIGHT AS
HIGH PRESSURE BUILDS BACK ACROSS THE REGION. TEMPERATURES DURING
THIS PERIOD WILL BE A FEW DEGREES BELOW NORMAL WITH HIGHS MOSTLY IN
THE LOW 80S (CENTRAL/SOUTH) AND MID TO UPPER 70S (NORTH). LOWS WILL
MOSTLY BE IN THE 50S NORTH/WEST AND LOW 60S SOUTH/EAST.
THE RETURN FLOW BEHIND THE DEPARTING HIGH WILL BRING INCREASED
MOISTURE AND BETTER CHC FOR SHOWERS FROM NEXT TUE INTO WED. WE
GENERALLY WENT ALONG WITH HPC POPS WITH ONLY MINOR CHANGES.
TEMPERATURES WILL BE WITHIN A FEW DEGREES OF NORMAL.
&&
.AVIATION /22Z THURSDAY THROUGH TUESDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.
CONDS RANGED FROM VFR TO IFR ACRS THE REGION, WITH THE LOWEST CIGS
RIGHT NOW ACRS THE I-95 CORRIDOR. EXPECT THE LWR (HOPEFULLY MVFR)
CIGS TO CONTINUE THRU THE EVENING UNTIL FROPA AND THEN AS THE WIND
BECOMES MORE WLY AND DRIER AIR MOVES IN, THE CIGS WILL IMPROVE TO
VFR. THIS COULD END UP HAPPENING SOONER THEN EXPECTED, OR LATER.
THERE ARE SOME TSRA OUT TWD LANCASTER AND WHILE ALL TSRA WAS
REMOVED FROM THE TAFS DUE TO THE ISOLD NATURE, THEY CAN NOT BE
RULED OUT, AT LEAST FOR THE NEXT FEW HOURS AND WILL BE HANDLED
WITH AMDTS IF THEY WERE TO OCCUR.
FRIDAY...VFR WITH SOME CLOUD BASES AROUND 5,000 FEET. WESTERLY WINDS
AROUND 10 KNOTS. HOWEVER, SOME GUSTS UP TO 20 KNOTS ARE ANTICIPATED
AS THE VERTICAL MIXING DEEPENS ESPECIALLY FROM MIDDAY ON.
OUTLOOK...
FRI NIGHT THRU SAT AFTERNOON...MOSTLY VFR.
SAT AFTERNOON THRU SUN MORNING...SCATTERED SHOWERS/TSTMS WITH
LOWER CONDITIONS POSSIBLE.
SUN AFTERNOON THRU TUESDAY...MOSTLY VFR. MORNING FOG POSSIBLE.
&&
.MARINE...
A SOUTHERLY FLOW WILL CONTINUE AHEAD OF A COLD FRONT. A WEAK SURFACE
LOW WILL MOVE ACROSS THE AREA THIS EVENING, FOLLOWED BY A COLD FRONT
LATER TONIGHT. THE SOUTHERLY FLOW HAS INCREASED WITH SOME GUSTS UP
TO 20 KNOTS. THIS IS EXPECTED TO CONTINUE FOR A TIME TONIGHT, THEN A
WIND SHIFT TO THE WEST LATE. A WESTERLY FLOW IS FORECAST FOR FRIDAY,
HOWEVER IT WILL BE LESS THAN 20 KNOTS. THE FLOW MAY ACTUALLY BACK A
BIT TO THE SOUTHWEST IN THE AFTERNOON GIVEN BETTER BOUNDARY LAYER
HEATING. SEAS HAVE BEEN SLOWLY BUILDING THIS AFTERNOON, AND WHILE
THEY COULD TOUCH 5 FEET ON THE OCEAN FOR A TIME WE BELIEVE THIS IS
MARGINAL AND MAY NOT LAST LONG. THEREFORE, WE WILL HOLD WITH NO
SMALL CRAFT ADVISORY ATTM. THE SEAS WILL LOWER SOME LATE AND ON
FRIDAY AS THE FLOW TURNS OFFSHORE FOR A TIME.
OUTLOOK...
SUB-SCA CONDITIONS EXPECTED ON THE WATERS THROUGH THE WEEKEND AND
EARLY NEXT WEEK. POSSIBLE SCA SEAS NEXT TUESDAY.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...O`HARA
NEAR TERM...GORSE/NIERENBERG
SHORT TERM...GORSE
LONG TERM...O`HARA
AVIATION...GORSE/NIERENBERG/O`HARA
MARINE...GORSE/O`HARA
AREA FORECAST DISCUSSION
NWS MIAMI FL
756 PM EDT FRI AUG 2 2013
.DISCUSSION...
MAIN ADJUSTMENTS TONIGHT ARE JUST FINE TUNING WHERE CONVECTION HAS
FIRED ACROSS SOUTH FLORIDA IN COMPARISON TO WHERE THE MODELS
ORIGINALLY HAD PLACED IT. CURRENT MODELS KEEP MOST OF THE
CONVECTION ALONG THE ATLANTIC COAST, NORTH OF MIAMI. HOWEVER, HAVE
KEPT ISOLATED SHOWERS AND THUNDERSTORM ACROSS SOUTH FLORIDA
THROUGH THE OVERNIGHT HOURS, DUE TO OUTFLOW BOUNDARIES FLOATING
AROUND THROUGHOUT THE CWA. THESE BOUNDARIES COULD ALLOW SOME
ISOLATED SHOWERS AND EVEN A THUNDERSTORM TO POP UP TONIGHT.
OTHERWISE, ONCE THE MAIN LINE THAT IS BEGINNING TO SHOW SIGNS OF
WEAKENING DISSIPATES, THE WEATHER SHOULD BE FAIRLY QUIET ACROSS
SOUTH FLORIDA.
&&
.AVIATION...
LINE OF SHRAS/TSRAS IN ASSOCIATION WITH THE REMNANTS OF DORIAN
CONTINUES TO SWEEP ACROSS PORTIONS OF NORTHEASTERN BROWARD COUNTY
AFFECTING KFXE AND KFLL WHERE ISOLATED MVFR/IFR CONDITIONS MAY BE
SEEN BRIEFLY WITHIN TSRAS. LATEST HRRR SHOWS THIS ACTIVITY
WEAKENING GRADUALLY OVER THE NEXT FEW HOURS. LIGHT SOUTHWESTERLY
FLOW SHOULD PREVAIL OVERNIGHT. ANOTHER ROUND OF SHRAS/TSRAS IS
EXPECTED TOMORROW BUT SHOULD BE MAINLY DIURNAL/SEA BREEZE INDUCED
ACTIVITY.
&&
.PREV DISCUSSION... /ISSUED 210 PM EDT FRI AUG 2 2013/
SHORT TERM (TONIGHT-SUNDAY NIGHT)...
THE WEAK SURFACE LOW PRESSURE WHICH IS THE REMNANTS OF DORIAN
CONTINUES OFF THE EAST FLORIDA COAST DRIFTING VERY SLOWLY TO THE
NORTH SNEAKING ITS WAY THROUGH A WEAKNESS IN THE MID LEVEL
SUBTROPICAL RIDGE. GLOBAL MODELS IN FAIR AGREEMENT IN LIFTING IT
SLOWLY NORTH TONIGHT AND THEN A GRADUAL SHIFT TO THE NORTH-NORTHEAST
ON SATURDAY AS IT GETS PICKED UP BY A FRONTAL BOUNDARY MOVING ONTO
THE EASTERN SEABOARD. THE DIFFERENCE IN OPINION IS ON JUST HOW THIS
WILL IMPACT THE WEATHER PARAMETERS OVER SOUTH FLORIDA ESPECIALLY
INTO LATE THIS AFTERNOON AND EVENING. SOME OF THE HIGH RESOLUTION
SHORT TERM MODELS ARE PERSISTENT IN DEVELOPING CONVECTION THIS
AFTERNOON AFTER 18Z. HOWEVER, THUS FAR THE WEAK MID LEVEL LAPSE
RATES AS SHOWN IN THE 12Z MFL SOUNDING HAVE HAMPERED THIS
DEVELOPMENT. SO WILL CONTINUE TO MONITOR FOR ANY CHANGES NEEDED TO
BE MADE. DUE TO DEVELOPMENT ALONG THE SEA BREEZES AND CONVECTION
MOVING ALONG THE EASTERN SIDE OF LAKE OKEECHOBEE GETTING CLOSE TO
OUR NORTHEAST ZONES, WILL CONTINUE WITH THE HIGH END POPS FOR NOW.
THE FRONTAL BOUNDARY WILL CONTINUE TO SHIFT EAST INTO THE ATLANTIC
OVER THE WEEKEND AS A DEEPENING TROUGH CONTINUES TO EVOLVE OVER THE
EASTERN U.S. WHILE MAINTAINING THE WEAKNESS IN THE SUBTROPICAL RIDGE
OVER SOUTH FLORIDA. THIS WILL ALSO MAINTAIN A DEEP TROPICAL AIRMASS
ACROSS THE REGION WITHOUT A SYNOPTIC SYSTEM TO PUSH IT OUT OF THE
AREA. FORECAST SOUNDINGS SHOW PWAT CONTINUING TO HOVER AROUND THE 2
INCH MARK. A SURFACE RIDGE WILL ALSO BE STRETCHED ACROSS THE FLORIDA
STRAITS THIS WEEKEND AND THIS WILL RESULT IN A WEAK SOUTHWEST TO
WEST STEERING FLOW FOR SOUTH FLORIDA SO THE CHANCES FOR CONVECTION
WILL BE NEAR AVERAGES FOR EARLY AUGUST WITH THE GREATEST THREAT
BEING THE INTERIOR AND EAST COAST METRO AREAS.
LONG TERM (MONDAY-FRIDAY)...
LOOKING INTO THE MIDDLE TO THE END OF THE WEEK, THE MID LEVEL
RIDGE WILL BUILD BACK IN ACROSS THE AREA WITH AT OR SLIGHTLY BELOW
POP AVERAGES FOR EARLY AUGUST. HOWEVER, BOTH THE GFS AND ECMWF
HAVE BEEN SHOWING A MID LEVEL INVERTED TROUGH ROTATING WEST BELOW
THE RIDGE AXIS AND THE LATEST RUN SHOWS IT A LITTLE STRONGER
REVERTING SOUTH FLORIDA BACK TO DEEP EASTERLY FLOW BY WEDNESDAY
INTO THE END OF THE WEEK. SO FOR NOW, WILL CONTINUE TO SHOW A
BROAD BRUSH CHANCE POP FORECAST FOR THE MAINLAND BUT IT COULD END
UP WITH HIGHER CHANCES FOR THE INTERIOR AND SOUTHWEST COAST.
MARINE...
A RATHER TRANQUIL MARINE FORECAST WITH THE LOW PRESSURE TROUGH
CONTINUING TO MOVE NORTH OF THE LOCAL WATERS OVER THE WEEKEND.
STILL, THERE COULD BE LOCALLY ROUGH SEAS NEAR STRONGER STORMS THAT
MAY MOVE OFF THE MAINLAND.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 77 92 78 93 / 50 40 20 40
FORT LAUDERDALE 79 90 79 91 / 40 30 20 30
MIAMI 79 92 78 92 / 20 40 20 40
NAPLES 77 91 77 90 / 20 30 20 30
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
DISCUSSION/MARINE/FIRE...13/SI
AVIATION/RADAR...10/CD
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
913 PM CDT FRI AUG 2 2013
.DISCUSSION...
911 PM CDT
EVENING UPDATE:
STRONG SHORTWAVE/MID LEVEL JET STREAK APPARENT ON WATER VAPOR
PUSHING IN FROM IOWA HAS SUSTAINED CONVECTION THAT FORMED ALONG
MOISTURE CONVERGENCE AXIS SOUTH OF INTERSTATE 80. THIS IS IN AN AIR
MASS THAT IS JUICY SOUTH OF COLD FRONT SINKING SOUTHWARD...WITH
PWATS OF 1.82 INCHES AND 1.72 INCHES RESPECTIVELY ON 00Z DVN AND
ILX RAOBS. RESULT HAS BEEN A MUCH NEEDED HEAVY RAIN EVENT FOR MANY
AREAS SOUTH OF INTERSTATE 80. THOUGH EAST-WEST ORIENTATION OF MAIN
BAND IS CONCERNING...PRECLUDING A BIGGER FLOOD THREAT IS DRY
ANTECEDENT CONDITIONS AND THE SLOW BUT STEADY SOUTHWARD PROGRESS.
NONETHELESS...HOURLY RADAR ESTIMATES OF 1 TO 1.5 INCHES PER HOUR
COULD RESULT IN PONDING ON SOME ROADWAYS. PRECIP LOADING IN MOST
INTENSE CORES COULD RESULT IN BRIEF GUSTY WINDS BUT BIGGEST
CONCERN IS THE HEAVY RAINFALL AND FAIRLY FREQUENT CLOUD TO GROUND
LIGHTNING. TO THE NORTH...AREA OF SPOTTY LIGHT RAIN/DRIZZLE WILL
PUSH EASTWARD AND LIKELY FIZZLE WITH TIME. MADE MINOR TWEAKS TO
POPS FOR PART OF THE EVENING AND OVERNIGHT...BUT REMAINDER OF
FORECAST APPEARS TO BE IN GOOD SHAPE...WITH ONLY TWEAKS TO HOURLY
TRENDS FOR TEMPS AND DEWPOINTS.
RC
&&
.PREV DISCUSSION...
248 PM CDT
THIS AFTERNOON AND TONIGHT...
A SURFACE TROUGH IS DRAPED FROM NORTHERN LAKE MICHIGAN SOUTHWEST
ACROSS SOUTHERN WISCONSIN AND INTO NORTHWESTERN ILLINOIS. AGITATED
CU FIELD HAS DEVELOPED OUT AHEAD OF THE TROUGH FROM DOWNTOWN CHICAGO
WEST ACROSS FAR NORTHERN LA SALLE COUNTY AND SOUTHERN LEE COUNTY.
HAVE RECENTLY SEEN THE FIRST RETURNS ON RADAR DEVELOPING IN THIS
AREA WHICH LATEST SPC MESOANALYSIS SHOWS AS AN AXIS OF 1500 J/KG
UNCAPPED MLCAPE. DEEP LAYER SHEAR IS MARGINAL AT THE MOMENT WITH
ABOUT 30 KTS...BUT THIS NUMBER MAY INCREASE AS WE HEAD INTO THE LATE
AFTERNOON AND EARLY EVENING AS MID LEVEL DISTURBANCE CURRENTLY OVER
NORTH CENTRAL IOWA APPROACHES. THIS FEATURE WILL ALSO INCREASE THE
BROAD SCALE ASCENT OVER THE AREA AND SHOULD LEAD TO AN INCREASE IN
THUNDERSTORM COVERAGE AS WELL AS ORGANIZATION. THERE IS CERTAINLY AN
INCREASED CONCERN FOR SEVERE WEATHER WHICH WILL HAVE TO BE MONITORED
OVER THE NEXT SEVERAL HOURS...ESPECIALLY AS WE GET A LITTLE BETTER
MID LEVEL LAPSE RATES OVER THE AREA AND THE AFOREMENTIONED SHEAR.
THE FOCUS SHOULD SHIFT SOUTH THROUGH THE EVENING. THERE WILL
SOME TRAINING ALONG THE BOUNDARY AS IT SAGS SOUTH THIS EVENING
LEADING TO LOCALIZED HEAVY RAIN AMOUNTS...THOUGH LATEST GUIDANCE
HAS SHIFTED THE FOCUS OF THE LOW LEVEL JET FARTHER EAST OF US
OVERNIGHT...SO APPEARS FOR NOW THAT THE THREAT FOR HEAVY RAIN
OVERNIGHT WILL ALSO BE FARTHER EAST.
SATURDAY THROUGH MONDAY...
SURFACE HIGH WILL BUILD SOUTHEAST FROM THE CANADIAN PRAIRIES...OVER
LAKE MICHIGAN SUNDAY...THEN EAST TO THE MID APPALACHIAN RANGE MONDAY
AND SHOULD PROVIDE A RELATIVELY BENIGN PERIOD OF WEATHER. WE DO GET
A GLANCING BLOW OF COOLER H85 AIR WHICH BOTTOMS OUT 8-9C ON
SUNDAY OVER NORTHEAST PORTIONS OF THE CWA. CANNOT COMPLETELY RULE
OUT SOME DIURNALLY DRIVEN AFTERNOON SHOWERS...AND MODELS DO HINT
AT SEVERAL WEAK SHORTWAVE TROUGHS RIDING DOWN THE RIDGE....BUT
SEEMS MORE LIKELY THAT SUBSIDENCE ASSOCIATED WITH MODERATE MID
LEVEL HEIGHT RISES FROM THE H5 RIDGE BUILDING ACROSS THE AREA WILL
LIMIT CU GROWTH. NAM AND GFS SOUNDINGS BOTH INDICATE A SUBSIDENCE
INVERSION SETTING UP AROUND 750 MB THROUGH THE WEEKEND WHICH WILL
LIMIT THE DEPTH OF THE VERTICAL GROWTH AND SHOULD KEEP THE AREA
DRY.
THIS PERIOD WILL SEE TEMPERATURES WELL BELOW SEASONAL NORMS. AS
MENTIONED...H85 TEMPS BOTTOM OUT SUNDAY AND UPPER AIR CLIMATOLOGY
SHOWS THAT 75% OF THE TIME SURFACE TEMPS TOP OUT AT 76 OR COOLER
WITH H85 TEMPS LESS THAN AROUND 9C. THE ECMWF/GEM/GFS ALL SUPPORT
TEMPS IN THE 71-73 FOR CHICAGO AND 73-74 FOR ROCKFORD...THOUGH THE
NAM WITH ITS TYPICAL HIGH BIAS IS SEVERAL DEGREES WARMER. GIVEN THAT
EVEN MOS GUIDANCE IS CALLING FOR MID 70S...AND WE SHOULD CLOUD UP
SOME WITH COLD AIR CU GROWTH...FELT COMFORTABLE DROPPING TEMPS A
COUPLE MORE DEGREES SUNDAY...CLOSER TO THE BLEND OF RAW GUIDANCE.
TUESDAY AND WEDNESDAY...
WITH THE HIGH SHIFTING EAST OF THE AREA...AND LOW PRESSURE DEEPENING
ACROSS THE CENTRAL/NORTHERN PLAINS...RETURN FLOW INTO THE MID
MISSOURI AND MID MISSISSIPPI VALLEYS SHOULD ALLOW UPPER 60 TO LOW 70
DEWPOINTS TO OVERSPREAD THE AREA WITH MODERATE TO STRONG INSTABILITY
DEVELOPING. STRONG WESTERLIES ALOFT COULD SET THE STAGE FOR A SEVERE
WEATHER OUTBREAK SOMEWHERE NEARBY WITH CURRENT MODEL SOLUTIONS
SETTING THE STAGE JUST TO OUR WEST. WHILE IT`S DIFFICULT TO PIN DOWN
A SEVERE WEATHER THREAT THIS FAR OUT...MODELS ARE IN DECENT
AGREEMENT AND WILL HAVE TO WATCH TUESDAY AND WEDNESDAY CLOSELY.
TEMPERATURES SHOULD RETURN TO SEASONABLE...AND IF ANYTHING CURRENT
PROJECTIONS OF LOW 80S MAY BE A BIT TOO COOL. A COLD FRONT IS
PROJECTED TO PUSH OVER THE AREA WEDNESDAY NIGHT.
THURSDAY AND FRIDAY...
MODELS DIVERGE QUITE A BIT ON HOW FAR SOUTH TO PUSH THE FRONTAL
BOUNDARY. THE GFS PUSHES THE FRONT WAY SOUTH INTO THE SOUTHEASTERN
STATES BY FRIDAY WHILE THE ECMWF STALLS THE FRONT OUT INTO SOUTHERN
ILLINOIS WITH PRECIPITATION OVERRUNNING THE BOUNDARY INTO THE
SOUTHERN CWA. WHILE THE NORTH HALF OF THE CWA SHOULD BE DRY EITHER
WAY...SOUTH OF I-80 ITS LESS CERTAIN. GIVEN THAT THE GFS ENSEMBLE
MAINTAINS SOME QPF FARTHER NORTH THAN THE OPERATIONAL RUN...WILL
MAINTAIN SOME CHANCE FOR THUNDERSTORMS ACROSS THE SOUTHERN CWA LATE
IN THE WEEK.
DEUBELBEISS
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 00Z...
* SCATTERED SHRA/ISOLATED TSRA CONTINUING TO SAG SOUTH OF MDW
EARLY THIS EVENING.
* A PERIOD OF -RA POSSIBLE DURING THE EVENING...BUT WITH VFR
CIG/VIS CONDITIONS ANTICIPATED.
* VARIABLE WIND DIRECTION AT MDW EARLY THIS EVENING DUE TO
CONVECTIVE OUTFLOW...WILL EVENTUALLY BECOME NORTHWEST LATER THIS
EVENING.
* NORTH WINDS BECOMING NORTHEAST AROUND 10 KT SATURDAY.
RATZER
//DISCUSSION...UPDATED 00Z...
COMBINED COLD FRONT AND CONVECTIVE OUTFLOW BOUNDARY WAS ORIENTED
FROM WEST-EAST ROUGHLY ALONG THE INTERSTATE 80 CORRIDOR EARLY THIS
EVENING. SCATTERED TSRA CONTINUED TO DEVELOP ALONG THIS BOUNDARY
FROM MLI-JOT-GYY...AND ADDITIONAL DEVELOPMENT IS LIKELY AS A MID-
LEVEL DISTURBANCE APPROACHES FROM IOWA...THOUGH THE BOUNDARY AND
ASSOCIATED FOCUS FOR SCATTERED TSRA SHOULD GRADUALLY DRIFT SOUTH
WITH TIME. SEVERAL OUTFLOW BOUNDARIES FROM EARLIER/ONGOING
CONVECTION AND LAKE BREEZE HAVE CONTINUED TO PRODUCE DEVELOPMENT
NEAR KMDW/MGYY AND THIS WILL LIKELY CONTINUE NEXT 1-2 HOURS BEFORE
FOCUS SHIFTS FARTHER SOUTH. CONVECTION SHOULD CONTINUE TO MOVE
SLOWLY OFF TO THE SOUTH/SOUTHEAST THROUGH LATE EVENING...AND
EVENTUALLY DIMINISH WITH THE DECREASE IN DIURNAL INSTABILITY.
THERE MAY BE A PERIOD OF SOME LIGHT RAIN ACROSS ALL TERMINALS
LATER THIS EVENING HOWEVER...AS MID-LEVEL MOISTURE ASSOCIATED
WITH IOWA DISTURBANCE MOVES THROUGH THE AREA.
WINDS HAVE SHIFTED TO THE NORTHWEST ACROSS RFD-DPA-ORD NORTH OF
THE FRONTAL BOUNDARY. WIND AT MDW/GYY SHOULD FOLLOW SUIT LATER
THIS EVENING AS THE FRONT SAGS OFF TO THE SOUTH. COOLER/DRIER AIR
WILL EVENTUALLY FILTER IN FROM THE NNW BEHIND THE FRONT...THOUGH
MOIST GROUND CONDITIONS FROM RECENT RAINS AND SLOW DROP OFF OF
SURFACE DEW POINT TEMPS BEHIND THE FRONT COULD RESULT IN SOME
SHALLOW PATCHY MVFR FOG OVERNIGHT. FAIRLY LOW CONFIDENCE IN
OCCURRENCE AT THIS POINT WITH FAIRLY PERSISTENT CLOUD COVER
EXPECTED FOR THE NEXT SEVERAL HOURS...BUT WILL MONITOR TRENDS
AFTER SUNSET FOR THIS POTENTIAL.
SATURDAY WILL FEATURE VFR CONDITIONS...WITH NORTHERLY WINDS AROUND
10 KT WITH A FEW HIGH GUSTS POSSIBLE. WINDS WILL LIKELY TAKE ON A
MORE PRONOUNCED NORTHEAST DIRECTION NEAR LAKE MICHIGAN AFFECTING
CHICAGO METRO TERMINALS.
RATZER
//ORD AND MDW CONFIDENCE...UPDATED 00Z...
* MEDIUM-HIGH CONFIDENCE IN SHRA/TSRA TRENDS THIS EVENING.
* HIGH CONFIDENCE IN OVERALL WIND TRENDS...EXCEPT MEDIUM-LOW
CONFIDENCE IN MDW WIND DIRECTION EARLY THIS EVE.
RATZER
//OUTLOOK FOR ORD/MDW FOR 12Z SUNDAY-12Z FRIDAY...UPDATED 00Z...
SUNDAY THROUGH THURSDAY...MAINLY VFR. CHANCE OF TSRA LATE MONDAY
INTO WEDNESDAY.
RATZER
&&
.MARINE...
232 PM CDT
THUNDERSTORMS WILL PRIMARILY REMAIN OVER THE FAR SOUTHERN END OF THE
LAKE THIS AFTERNOON AND THE STRONGER STORMS MAY PRODUCE GALE FORCE
GUSTS. SOUTHWEST WINDS WILL BECOME NORTH TONIGHT BEHIND A COOL
FRONT...AND NORTH/NORTHWEST WINDS ARE EXPECTED ACROSS THE LAKE
THROUGH SUNDAY. HIGH PRESSURE MOVES OVER THE LAKE SATURDAY...AND
WINDS BECOME SOUTHEAST BY MONDAY MORNING. THE HIGH SHIFTS EAST OF
THE LAKE MONDAY AND ANOTHER LOW IS EXPECTED TO PASS NORTH OF THE
LAKE THROUGH ONTARIO MID NEXT WEEK. GUIDANCE STILL FEATURES
DIFFERENCES ON TIMING OF THE LOW...BUT TUESDAY NIGHT OR WEDNESDAY
LOOKS LIKE THE BEST TIME FRAME. GUIDANCE ALSO SUGGESTS ANOTHER LOW
MOVES IN FROM THE SOUTHWEST NEXT THURSDAY.
JEE
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
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[top]
Area Forecast Discussion
National Weather Service Lincoln IL
837 PM CDT Fri Aug 2 2013
.DISCUSSION...
ISSUED 830 PM CDT Fri Aug 2 2013
Latest surface analysis indicating the cold front pressing south
through north central Illinois this evening...just north of our
forecast area. Scattered showers and thunderstorms were occurring
just ahead of the boundary this evening and the activity was
shifting east and southeast...which should encompass at least
our northeast third of the forecast area this evening into the
overnight hours. Short term models suggest the showers will
gradually decrease in coverage later this evening as the front
shifts further south. Instability not that great with MUCAPEs
of 500-1000 j/kg early this evening with the greater instability
much further to our southwest, over parts of southern Missouri
into SE Kansas. Front should be in close to the I-70 corridor
by 12z Saturday, thus the higher rain chances tomorrow will be
across the southeast. Have already updated the zones earlier
this evening, so other than some adjustments to the sky grids
and hourly temperatures in the grids, no other changes will
be needed that would warrant another ZFP update.
SMITH
&&
.AVIATION...
ISSUED 540 PM CDT Fri Aug 2 2013
Cold front was currently located just south of ORD and about to
push thru MLI early this evening. Widely scattered showers and
thunderstorms were occurring ahead of the boundary and are
expected to continue with the front to the east and south across
our area this evening. Coverage still appears too limited to go
much more than VCTS this evening based on current and expected
trends with the precip ahead of the front. The next question becomes
after the frontal passage late tonight, how much, if any MVFR cigs
will occur just behind the front. Passed few runs have been playing
it down with respect to any widespread mvfr cigs/vsbys, but will
have to watch for some patchy ground fog to form late tonight as
winds will be light and variable before mixing out to a northeast
direction at 10 kts by mid or late Saturday morning.
Smith
&&
.PREV DISCUSSION...
Issued 248 PM CDT Fri Aug 2 2013
Early afternoon surface map showing the cold front had crossed
much of Wisconsin, then extended westward across southern Iowa to
along the Kansas/Nebraska border. Precipitation so far has been
pretty sparse across the area, with just some high-based very
light showers tracking just south of the I-72 corridor.
Subsidence in the wake of morning convection in northern Illinois
actually allowed for a good deal of clearing across southeast Iowa
and northern Illinois, although diurnal cumulus has been filling
in rather quickly the last couple hours. The clearing helped to
get the air more unstable, with CAPE`s of around 2000 J/kg across
the northern third of the state with little cap, as evidenced by
scattered storms forming around 2 pm just ahead of the front from
Moline to Chicago.
The primary forecast concern in the short term is with the
convective chances over the next 18-24 hours. Rain chances in the
longer range are also a concern due to MCS potential through the
first half of next week.
SHORT TERM...Tonight through Sunday...
Morning model runs have significantly struggled with the
convective trends thus far, so confidence in this part of the
forecast is lower than normal. The most recent HRRR model appears
to be closest to reality, and shows that the broken line of
showers and storms to our north will be drifting across areas
along and north of I-74 into the evening. Scattered storms
currently in Missouri should track eastward as well, affecting
the remainder of the forecast area. Precipitable water values of
1.75 to 2 inches should help produce some heavy rain with the
stronger storms. Can`t rule out some gusty winds and hail as well,
but wind shear overall is rather weak in our area and anything
that does approach severe levels should be the pulse type.
Overnight, the NAM and GFS already have the precipitation on the
wane with a faster push to the cold front, while the ECMWF and
Canadian models linger the showers/storms most of the night with a
slower frontal passage. Have gone with the highest PoPs in the
evening, but kept healthy chances over most of the area overnight.
Not too many changes needed for Saturday, as the frontal boundary
should be through most of the area by midday. Have kept the
northwest CWA dry all day, and continued with all areas north of
I-72 dry by afternoon. All precipitation should be out of the area
by early evening, as high pressure builds southeast into the
Midwest, and cooler/less humid air can be expected the rest of the
weekend.
LONG TERM...Monday through Friday...
Upper level pattern looking fairly agreeable among the GFS and
ECMWF models, with initial northwest flow flattening as a strong
cutoff low sinks southward across Manitoba. GFS remains stronger
with the high keeping our area dry into Monday, while the ECMWF
keeps us on the periphery of the MCS track across Missouri. Have
limited any PoPs to the far southwest for Sunday night and even
then just kept them at 20 percent. Next shortwave on Tuesday
should help boot the high eastward, but convection along the Gulf
Coast will help rob some of the return moisture advection for a
time, so have held off on any decent rain chances until Tuesday
night. Getting into midweek, a surface boundary will become quasi-
stationary as it becomes parallel to the upper flow. The model
differences widen at this point, with the GFS pushing the boundary
through us by late Wednesday night and the ECMWF keeping it north
of the area until Thursday evening. The ultimate position and
associated convective chances will come down to timing of fast
moving shortwaves between the upper low and a sprawling upper high
over the southern U.S. For now have favored a bit of a more
southern push with a period of drier conditions Wednesday night
and Thursday with increasing PoPs again after that.
Geelhart
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
653 PM CDT FRI AUG 2 2013
.DISCUSSION...
248 PM CDT
THIS AFTERNOON AND TONIGHT...
A SURFACE TROUGH IS DRAPED FROM NORTHERN LAKE MICHIGAN SOUTHWEST
ACROSS SOUTHERN WISCONSIN AND INTO NORTHWESTERN ILLINOIS. AGITATED
CU FIELD HAS DEVELOPED OUT AHEAD OF THE TROUGH FROM DOWNTOWN CHICAGO
WEST ACROSS FAR NORTHERN LA SALLE COUNTY AND SOUTHERN LEE COUNTY.
HAVE RECENTLY SEEN THE FIRST RETURNS ON RADAR DEVELOPING IN THIS
AREA WHICH LATEST SPC MESOANALYSIS SHOWS AS AN AXIS OF 1500 J/KG
UNCAPPED MLCAPE. DEEP LAYER SHEAR IS MARGINAL AT THE MOMENT WITH
ABOUT 30 KTS...BUT THIS NUMBER MAY INCREASE AS WE HEAD INTO THE LATE
AFTERNOON AND EARLY EVENING AS MID LEVEL DISTURBANCE CURRENTLY OVER
NORTH CENTRAL IOWA APPROACHES. THIS FEATURE WILL ALSO INCREASE THE
BROAD SCALE ASCENT OVER THE AREA AND SHOULD LEAD TO AN INCREASE IN
THUNDERSTORM COVERAGE AS WELL AS ORGANIZATION. THERE IS CERTAINLY AN
INCREASED CONCERN FOR SEVERE WEATHER WHICH WILL HAVE TO BE MONITORED
OVER THE NEXT SEVERAL HOURS...ESPECIALLY AS WE GET A LITTLE BETTER
MID LEVEL LAPSE RATES OVER THE AREA AND THE AFOREMENTIONED SHEAR.
THE FOCUS SHOULD SHIFT SOUTH THROUGH THE EVENING. THERE WILL
SOME TRAINING ALONG THE BOUNDARY AS IT SAGS SOUTH THIS EVENING
LEADING TO LOCALIZED HEAVY RAIN AMOUNTS...THOUGH LATEST GUIDANCE
HAS SHIFTED THE FOCUS OF THE LOW LEVEL JET FARTHER EAST OF US
OVERNIGHT...SO APPEARS FOR NOW THAT THE THREAT FOR HEAVY RAIN
OVERNIGHT WILL ALSO BE FARTHER EAST.
SATURDAY THROUGH MONDAY...
SURFACE HIGH WILL BUILD SOUTHEAST FROM THE CANADIAN PRAIRIES...OVER
LAKE MICHIGAN SUNDAY...THEN EAST TO THE MID APPALACHIAN RANGE MONDAY
AND SHOULD PROVIDE A RELATIVELY BENIGN PERIOD OF WEATHER. WE DO GET
A GLANCING BLOW OF COOLER H85 AIR WHICH BOTTOMS OUT 8-9C ON
SUNDAY OVER NORTHEAST PORTIONS OF THE CWA. CANNOT COMPLETELY RULE
OUT SOME DIURNALLY DRIVEN AFTERNOON SHOWERS...AND MODELS DO HINT
AT SEVERAL WEAK SHORTWAVE TROUGHS RIDING DOWN THE RIDGE....BUT
SEEMS MORE LIKELY THAT SUBSIDENCE ASSOCIATED WITH MODERATE MID
LEVEL HEIGHT RISES FROM THE H5 RIDGE BUILDING ACROSS THE AREA WILL
LIMIT CU GROWTH. NAM AND GFS SOUNDINGS BOTH INDICATE A SUBSIDENCE
INVERSION SETTING UP AROUND 750 MB THROUGH THE WEEKEND WHICH WILL
LIMIT THE DEPTH OF THE VERTICAL GROWTH AND SHOULD KEEP THE AREA
DRY.
THIS PERIOD WILL SEE TEMPERATURES WELL BELOW SEASONAL NORMS. AS
MENTIONED...H85 TEMPS BOTTOM OUT SUNDAY AND UPPER AIR CLIMATOLOGY
SHOWS THAT 75% OF THE TIME SURFACE TEMPS TOP OUT AT 76 OR COOLER
WITH H85 TEMPS LESS THAN AROUND 9C. THE ECMWF/GEM/GFS ALL SUPPORT
TEMPS IN THE 71-73 FOR CHICAGO AND 73-74 FOR ROCKFORD...THOUGH THE
NAM WITH ITS TYPICAL HIGH BIAS IS SEVERAL DEGREES WARMER. GIVEN THAT
EVEN MOS GUIDANCE IS CALLING FOR MID 70S...AND WE SHOULD CLOUD UP
SOME WITH COLD AIR CU GROWTH...FELT COMFORTABLE DROPPING TEMPS A
COUPLE MORE DEGREES SUNDAY...CLOSER TO THE BLEND OF RAW GUIDANCE.
TUESDAY AND WEDNESDAY...
WITH THE HIGH SHIFTING EAST OF THE AREA...AND LOW PRESSURE DEEPENING
ACROSS THE CENTRAL/NORTHERN PLAINS...RETURN FLOW INTO THE MID
MISSOURI AND MID MISSISSIPPI VALLEYS SHOULD ALLOW UPPER 60 TO LOW 70
DEWPOINTS TO OVERSPREAD THE AREA WITH MODERATE TO STRONG INSTABILITY
DEVELOPING. STRONG WESTERLIES ALOFT COULD SET THE STAGE FOR A SEVERE
WEATHER OUTBREAK SOMEWHERE NEARBY WITH CURRENT MODEL SOLUTIONS
SETTING THE STAGE JUST TO OUR WEST. WHILE IT`S DIFFICULT TO PIN DOWN
A SEVERE WEATHER THREAT THIS FAR OUT...MODELS ARE IN DECENT
AGREEMENT AND WILL HAVE TO WATCH TUESDAY AND WEDNESDAY CLOSELY.
TEMPERATURES SHOULD RETURN TO SEASONABLE...AND IF ANYTHING CURRENT
PROJECTIONS OF LOW 80S MAY BE A BIT TOO COOL. A COLD FRONT IS
PROJECTED TO PUSH OVER THE AREA WEDNESDAY NIGHT.
THURSDAY AND FRIDAY...
MODELS DIVERGE QUITE A BIT ON HOW FAR SOUTH TO PUSH THE FRONTAL
BOUNDARY. THE GFS PUSHES THE FRONT WAY SOUTH INTO THE SOUTHEASTERN
STATES BY FRIDAY WHILE THE ECMWF STALLS THE FRONT OUT INTO SOUTHERN
ILLINOIS WITH PRECIPITATION OVERRUNNING THE BOUNDARY INTO THE
SOUTHERN CWA. WHILE THE NORTH HALF OF THE CWA SHOULD BE DRY EITHER
WAY...SOUTH OF I-80 ITS LESS CERTAIN. GIVEN THAT THE GFS ENSEMBLE
MAINTAINS SOME QPF FARTHER NORTH THAN THE OPERATIONAL RUN...WILL
MAINTAIN SOME CHANCE FOR THUNDERSTORMS ACROSS THE SOUTHERN CWA LATE
IN THE WEEK.
DEUBELBEISS
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 00Z...
* SCATTERED SHRA/ISOLATED TSRA CONTINUING TO SAG SOUTH OF MDW
EARLY THIS EVENING.
* A PERIOD OF -RA POSSIBLE DURING THE EVENING...BUT WITH VFR
CIG/VIS CONDITIONS ANTICIPATED.
* VARIABLE WIND DIRECTION AT MDW EARLY THIS EVENING DUE TO
CONVECTIVE OUTFLOW...WILL EVENTUALLY BECOME NORTHWEST LATER THIS
EVENING.
* NORTH WINDS BECOMING NORTHEAST AROUND 10 KT SATURDAY.
RATZER
//DISCUSSION...UPDATED 00Z...
COMBINED COLD FRONT AND CONVECTIVE OUTFLOW BOUNDARY WAS ORIENTED
FROM WEST-EAST ROUGHLY ALONG THE INTERSTATE 80 CORRIDOR EARLY THIS
EVENING. SCATTERED TSRA CONTINUED TO DEVELOP ALONG THIS BOUNDARY
FROM MLI-JOT-GYY...AND ADDITIONAL DEVELOPMENT IS LIKELY AS A MID-
LEVEL DISTURBANCE APPROACHES FROM IOWA...THOUGH THE BOUNDARY AND
ASSOCIATED FOCUS FOR SCATTERED TSRA SHOULD GRADUALLY DRIFT SOUTH
WITH TIME. SEVERAL OUTFLOW BOUNDARIES FROM EARLIER/ONGOING
CONVECTION AND LAKE BREEZE HAVE CONTINUED TO PRODUCE DEVELOPMENT
NEAR KMDW/MGYY AND THIS WILL LIKELY CONTINUE NEXT 1-2 HOURS BEFORE
FOCUS SHIFTS FARTHER SOUTH. CONVECTION SHOULD CONTINUE TO MOVE
SLOWLY OFF TO THE SOUTH/SOUTHEAST THROUGH LATE EVENING...AND
EVENTUALLY DIMINISH WITH THE DECREASE IN DIURNAL INSTABILITY.
THERE MAY BE A PERIOD OF SOME LIGHT RAIN ACROSS ALL TERMINALS
LATER THIS EVENING HOWEVER...AS MID-LEVEL MOISTURE ASSOCIATED
WITH IOWA DISTURBANCE MOVES THROUGH THE AREA.
WINDS HAVE SHIFTED TO THE NORTHWEST ACROSS RFD-DPA-ORD NORTH OF
THE FRONTAL BOUNDARY. WIND AT MDW/GYY SHOULD FOLLOW SUIT LATER
THIS EVENING AS THE FRONT SAGS OFF TO THE SOUTH. COOLER/DRIER AIR
WILL EVENTUALLY FILTER IN FROM THE NNW BEHIND THE FRONT...THOUGH
MOIST GROUND CONDITIONS FROM RECENT RAINS AND SLOW DROP OFF OF
SURFACE DEW POINT TEMPS BEHIND THE FRONT COULD RESULT IN SOME
SHALLOW PATCHY MVFR FOG OVERNIGHT. FAIRLY LOW CONFIDENCE IN
OCCURRENCE AT THIS POINT WITH FAIRLY PERSISTENT CLOUD COVER
EXPECTED FOR THE NEXT SEVERAL HOURS...BUT WILL MONITOR TRENDS
AFTER SUNSET FOR THIS POTENTIAL.
SATURDAY WILL FEATURE VFR CONDITIONS...WITH NORTHERLY WINDS AROUND
10 KT WITH A FEW HIGH GUSTS POSSIBLE. WINDS WILL LIKELY TAKE ON A
MORE PRONOUNCED NORTHEAST DIRECTION NEAR LAKE MICHIGAN AFFECTING
CHICAGO METRO TERMINALS.
RATZER
//ORD AND MDW CONFIDENCE...UPDATED 00Z...
* MEDIUM-HIGH CONFIDENCE IN SHRA/TSRA TRENDS THIS EVENING.
* HIGH CONFIDENCE IN OVERALL WIND TRENDS...EXCEPT MEDIUM-LOW
CONFIDENCE IN MDW WIND DIRECTION EARLY THIS EVE.
RATZER
//OUTLOOK FOR ORD/MDW FOR 12Z SUNDAY-12Z FRIDAY...UPDATED 00Z...
SUNDAY THROUGH THURSDAY...MAINLY VFR. CHANCE OF TSRA LATE MONDAY
INTO WEDNESDAY.
RATZER
&&
.MARINE...
232 PM CDT
THUNDERSTORMS WILL PRIMARILY REMAIN OVER THE FAR SOUTHERN END OF THE
LAKE THIS AFTERNOON AND THE STRONGER STORMS MAY PRODUCE GALE FORCE
GUSTS. SOUTHWEST WINDS WILL BECOME NORTH TONIGHT BEHIND A COOL
FRONT...AND NORTH/NORTHWEST WINDS ARE EXPECTED ACROSS THE LAKE
THROUGH SUNDAY. HIGH PRESSURE MOVES OVER THE LAKE SATURDAY...AND
WINDS BECOME SOUTHEAST BY MONDAY MORNING. THE HIGH SHIFTS EAST OF
THE LAKE MONDAY AND ANOTHER LOW IS EXPECTED TO PASS NORTH OF THE
LAKE THROUGH ONTARIO MID NEXT WEEK. GUIDANCE STILL FEATURES
DIFFERENCES ON TIMING OF THE LOW...BUT TUESDAY NIGHT OR WEDNESDAY
LOOKS LIKE THE BEST TIME FRAME. GUIDANCE ALSO SUGGESTS ANOTHER LOW
MOVES IN FROM THE SOUTHWEST NEXT THURSDAY.
JEE
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
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WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
Area Forecast Discussion
National Weather Service Lincoln IL
540 PM CDT Fri Aug 2 2013
.DISCUSSION...
Issued 248 PM CDT Fri Aug 2 2013
Early afternoon surface map showing the cold front had crossed
much of Wisconsin, then extended westward across southern Iowa to
along the Kansas/Nebraska border. Precipitation so far has been
pretty sparse across the area, with just some high-based very
light showers tracking just south of the I-72 corridor.
Subsidence in the wake of morning convection in northern Illinois
actually allowed for a good deal of clearing across southeast Iowa
and northern Illinois, although diurnal cumulus has been filling
in rather quickly the last couple hours. The clearing helped to
get the air more unstable, with CAPE`s of around 2000 J/kg across
the northern third of the state with little cap, as evidenced by
scattered storms forming around 2 pm just ahead of the front from
Moline to Chicago.
The primary forecast concern in the short term is with the
convective chances over the next 18-24 hours. Rain chances in the
longer range are also a concern due to MCS potential through the
first half of next week.
SHORT TERM...Tonight through Sunday...
Morning model runs have significantly struggled with the
convective trends thus far, so confidence in this part of the
forecast is lower than normal. The most recent HRRR model appears
to be closest to reality, and shows that the broken line of
showers and storms to our north will be drifting across areas
along and north of I-74 into the evening. Scattered storms
currently in Missouri should track eastward as well, affecting
the remainder of the forecast area. Precipitable water values of
1.75 to 2 inches should help produce some heavy rain with the
stronger storms. Can`t rule out some gusty winds and hail as well,
but wind shear overall is rather weak in our area and anything
that does approach severe levels should be the pulse type.
Overnight, the NAM and GFS already have the precipitation on the
wane with a faster push to the cold front, while the ECMWF and
Canadian models linger the showers/storms most of the night with a
slower frontal passage. Have gone with the highest PoPs in the
evening, but kept healthy chances over most of the area overnight.
Not too many changes needed for Saturday, as the frontal boundary
should be through most of the area by midday. Have kept the
northwest CWA dry all day, and continued with all areas north of
I-72 dry by afternoon. All precipitation should be out of the area
by early evening, as high pressure builds southeast into the
Midwest, and cooler/less humid air can be expected the rest of the
weekend.
LONG TERM...Monday through Friday...
Upper level pattern looking fairly agreeable among the GFS and
ECMWF models, with initial northwest flow flattening as a strong
cutoff low sinks southward across Manitoba. GFS remains stronger
with the high keeping our area dry into Monday, while the ECMWF
keeps us on the periphery of the MCS track across Missouri. Have
limited any PoPs to the far southwest for Sunday night and even
then just kept them at 20 percent. Next shortwave on Tuesday
should help boot the high eastward, but convection along the Gulf
Coast will help rob some of the return moisture advection for a
time, so have held off on any decent rain chances until Tuesday
night. Getting into midweek, a surface boundary will become quasi-
stationary as it becomes parallel to the upper flow. The model
differences widen at this point, with the GFS pushing the boundary
through us by late Wednesday night and the ECMWF keeping it north
of the area until Thursday evening. The ultimate position and
associated convective chances will come down to timing of fast
moving shortwaves between the upper low and a sprawling upper high
over the southern U.S. For now have favored a bit of a more
southern push with a period of drier conditions Wednesday night
and Thursday with increasing PoPs again after that.
Geelhart
&&
.AVIATION...
ISSUED 540 PM CDT Fri Aug 2 2013
Cold front was currently located just south of ORD and about to
push thru MLI early this evening. Widely scattered showers and
thunderstorms were occurring ahead of the boundary and are
expected to continue with the front to the east and south across
our area this evening. Coverage still appears too limited to go
much more than VCTS this evening based on current and expected
trends with the precip ahead of the front. The next question becomes
after the frontal passage late tonight, how much, if any MVFR cigs
will occur just behind the front. Passed few runs have been playing
it down with respect to any widespread mvfr cigs/vsbys, but will
have to watch for some patchy ground fog to form late tonight as
winds will be light and variable before mixing out to a northeast
direction at 10 kts by mid or late Saturday morning.
Smith
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS DES MOINES IA
650 PM CDT FRI AUG 2 2013
.UPDATE...
ISSUED AT 647 PM CDT FRI AUG 2 2013
WILL UPDATE FCST SH0RTLY TO REDUCE POPS ACRS MUCH OF THE CWA. AREA
OF -RA/SHRA ACROSS THE NORTHEASTERN CWA IS BEING FORCED IN PART BY
700-500 MB DIFF VORT ADVECTION AS DEPICTED ON LATEST RAP MODEL
RUN. MODELS SLIDE THE DVA OFF TO THE EAST THIS EVENING AND LEAVE A
LACK OF ORGANIZED FORCING AND COINCIDENT MOISTURE FOR PRECIP.
ACRS THE SOUTHERN CWA...SFC COLD FRONT HAS PUSHED SOUTH OF THE IA-MO
BORDER...THUS SIGNIFICANTLY REDUCING THE RISK OF WIDESPREAD...ORGANIZED
TSRA THERE.
&&
.SHORT TERM.../TONIGHT /...
ISSUED AT 341 PM CDT FRI AUG 2 2013
AREA OF SHOWERS/EMBEDDED THUNDERSTORMS HAS BEEN STEADILY
PROGRESSING EASTWARD ACROSS THE NORTHERN CWA WITH A SLIGHT SHIFT
SOUTH. EXPECT THIS AREA TO CONTINUE ITS CURRENT PROGRESSION OVER
THE NEXT FEW HOURS...WITH SECONDARY AREA OF RAIN/ISOLATED THUNDER
EXPECTED TO STILL PUSH EAST BUT BEGIN TO DROP SOUTH ACROSS THE
CENTRAL CWA TOWARD EARLY/MID EVENING AS WEAK FRONT ALOFT SLOWLY
MOVES SOUTH. THIS WILL TREND TOWARD A SOUTHERN PROGRESSION OF
RAIN/THUNDER CHANCES THROUGHOUT THE EVENING...WITH RAIN CHANCES
ENDING TOWARD MIDNIGHT OR SHORTLY AFTER AS FRONTAL BOUNDARY ALOFT
PROGRESSES SOUTH OF THE STATE. A FEW VERY WEAK ECHOES DEVELOPING
ALONG OUTFLOW BOUNDARY FROM NORTHERN IOWA ACTIVITY. THIS WILL BE
THE MAIN AREA TO WATCH IF ANY CHANCE OF STRONGER STORMS/ISOLATED
SEVERE ACTIVITY. INSTABILITY FAIRLY WEAK AROUND 500 TO 1000
J/KG...WITH EFFECTIVE SHEAR MORE IMPRESSIVE AT 45 TO 50 KTS.
THEREFORE IS STRONGER STORMS ORGANIZE COULD HAVE A FEW ISOLATED
LARGE HAIL/DAMAGING WINDS REPORTS ACROSS SOUTHERN IOWA.
.LONG TERM.../SATURDAY THROUGH FRIDAY/...
ISSUED AT 341 PM CDT FRI AUG 2 2013
MAIN FORECAST CONCERN IS WITH PERIODIC PRECIP CHANCES BEGINNING
SUNDAY AND ENDING WEDNESDAY INTO EARLY THURSDAY. MODELS ARE IN
POOR AGREEMENT PAST MONDAY WRT TO TIMING AND LOCATION OF
SHORTWAVES ACROSS THE REGION. USED A BLEND OF THE HI-RES WRF AND
SREF FOR SUNDAY INTO EARLY MONDAY...PERSISTENCE MONDAY AND
TUESDAY....THEN LEANED TOWARD THE DRIER GFS WEDNESDAY THROUGH
FRIDAY.
SATURDAY THROUGH MONDAY...SURFACE HIGH PRESSURE WILL BUILD INTO
THE REGION SATURDAY AND SHIFT EAST BY SUNDAY. MID LEVEL VORT MAX
TRACKS ACROSS NEBRASKA AND INTO NORTHERN MISSOURI ON SUNDAY AND
MAY CLIP THE SOUTHWEST PORTION OF THE FORECAST AREA AND KEPT SMALL
CHANCE POPS GOING DURING THE DAY SUNDAY. ANOTHER WEAK SHORTWAVE
LOOKS TO RIDE ALONG THE 500MB FLOW LATE SUNDAY EVENING INTO
EARLY MONDAY. THIS LOOKS TO BE A BIT FURTHER NORTH POTENTIALLY
AFFECTING MORE OF THE FORECAST AREA. HOWEVER...SYSTEM IS LACKING
SIGNIFICANT MOISTURE AND FORCING AND ONLY HAVE SLIGHT POPS GOING
THROUGH MONDAY MORNING.
TUESDAY AND WEDNESDAY...BEST CHANCE OF RAIN ACROSS THE FORECAST
AREA WILL BE TUESDAY NIGHT INTO WEDNESDAY AS AN UPPER LOW OVER
SOUTH CENTRAL CANADA SWINGS A COLD FRONT THROUGH THE STATE. HAVE
BEST POPS OVER SOUTHERN IOWA WHERE STRONGEST CONVERGENCE AND BEST
MOISTURE IS LOCATED TUESDAY NIGHT.
THURSDAY AND FRIDAY...TRENDED TOWARDS A DRIER FORECAST EVEN THOUGH
BOTH THE GFS/ECMWF/GEM HAVE SOME SORT OF PRECIP AFFECTING THE
FORECAST ARE DURING THIS TIME. FELT CONFIDENT ENOUGH TO TREND
DRIER WITH THE UNCERTAINTY ATTM WRT TO ANY SIGNIFICANT SYSTEM
MOVING ACROSS THE REGION.
&&
.AVIATION...03/00Z
ISSUED AT 629 PM CDT FRI AUG 2 2013
VFR CONDITIONS EXPECTED DURG THE FCST PD AS HIGH PRES AT THE SFC
FILTERS INTO MUCH OF IA. AREA OF -RA/SHRA WILL AFFECT THE KALO
TERMINAL AREA THROUGH 02-03Z AS IT CONTINUES SLIDING ESE. CONDITIONS
WITHIN THE PRECIP WILL REMAIN VFR HOWEVER.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...ZOGG
SHORT TERM...BEERENDS
LONG TERM...PODRAZIK
AVIATION...ZOGG
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
326 PM CDT THU AUG 1 2013
.SYNOPSIS...
ISSUED AT 324 PM CDT THU AUG 1 2013
12Z UA ANALYSIS HAS A WEAK 850MB COLD FRONT FROM LAKE HURON TO THE
MN/IA BORDER. A RESPECTABLE SHORTWAVE RAN FROM THE DAKOTAS INTO
WESTERN NEBRASKA WHILE A MOISTURE GRADIENT RAN FROM WESTERN MISSOURI
INTO NEBRASKA. SATELLITE/RADAR TRENDS THROUGH MID AFTERNOON SHOW
CONVECTION ASSOCIATED WITH THE DAKOTAS SHORT WAVE AND NEW CONVECTION
ON THE NORTH EDGE OF THE MOISTURE GRADIENT ACROSS NEBRASKA.
18Z SFC ANALYSIS HAS WEAK LOWS IN COLORADO AND SOUTHEAST WYOMING AND
ANOTHER IN WESTERN MINNESOTA. WEAK BOUNDARIES CONNECTED THE
MINNESOTA LOW TO THE LOW IN WYOMING WHILE SEVERAL WEAK TROFS WERE
ACROSS THE GREAT LAKES. A SFC MOISTURE BOUNDARY RAN FROM NEBRASKA
INTO NORTHWEST MISSOURI. DEW POINTS WERE IN THE 50S ACROSS THE GREAT
LAKES AND UPPER MIDWEST WITH 60S ACROSS MUCH OF THE PLAINS AND OHIO
VALLEY. DEW POINTS IN THE 70S WERE ACROSS THE SOUTHERN PLAINS AND
DEEP SOUTH.
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 324 PM CDT THU AUG 1 2013
DEEP MIXING THIS AFTERNOON HAS DROPPED THE DEW POINTS INTO THE LOW
TO MID 50S ACROSS WISCONSIN...NORTHERN ILLINOIS...AND NORTHEAST
IOWA. THE DEEP MIXING COMBINED WITH SUBSIDENCE HAS PREVENTED ANY
DIURNAL CLOUD DEVELOPMENT.
BASED ON SATELLITE AND RAP TRENDS USING THE MCS/LIFT TOOLS...THE
AGITATED CU DEVELOPMENT ALONG THE MN/IA BORDER SHOULD SLOWLY EVOLVE
INTO ISOLATED TO SCATTERED SHOWERS AND POSSIBLY A COUPLE OF
THUNDERSTORMS ACROSS THE NORTHERN CWFA DURING THE EVENING HOURS. THE
MORE SUBSTANTIAL STORM DEVELOPMENT ACROSS NEBRASKA MAY INDUCE SOME
ISOLATED SHOWERS OR A THUNDERSTORM ACROSS THE SOUTHERN HALF OF THE
CWFA BY MID TO LATE EVENING. STARTING AROUND MIDNIGHT THERE MAY BE A
LULL IN ACTIVITY FOR SEVERAL HOURS.
THE MCS TOOL IS REASONABLY CONSISTENT INDICATING A RESPECTABLE MCS
WILL DEVELOP THIS EVENING ACROSS EASTERN NEBRASKA/WESTERN IOWA AND
MOVE EAST SOUTHEAST OVERNIGHT ARRIVING IN THE SOUTHERN TWO THIRDS OF
THE CWFA PRIOR TO SUNRISE. CORFIDI VECTORS DO NOT SUGGEST ANY BACK
BUILDING BUT THE BACKWARD PROPAGATING VECTORS DO BECOME
PERPENDICULAR ACROSS THE SOUTHERN HALF OF THE CWFA SUGGESTING A WEAK
THREAT OF STORMS MOVING OVER THE SAME AREA.
THE DRIER AIR ACROSS THE AREA MAY RESULT IN SOME SMALL HAIL IN THE
STRONGER STORMS BEFORE THE ATMOSPHERE SATURATES LATE TONIGHT.
ON FRIDAY THE NOCTURNAL MCS WILL BE OVER THE CWFA DURING THE MORNING
HOURS AND WILL SLOWLY DECAY INTO MORE SHOWERS THAN THUNDERSTORMS BY
LATE MORNING. BOUNDARIES LEFT OVER FROM THIS MCS WILL THEN PROVIDE
THE FOCUS FOR NEW DEVELOPMENT DURING THE AFTERNOON. THE MCS TOOL
WHEN APPLIED TO SOME MODELS SUGGESTS THE POTENTIAL FOR ANOTHER MCS
AFFECTING THE AREA LATE FRIDAY AFTERNOON AND INTO FRIDAY NIGHT.
TEMPERATURES ON FRIDAY MAY REMAIN IN THE 60S FOR THE MORNING UNTIL
THE RAIN ENDS AND THEN CLIMBING INTO THE 70S DURING THE
AFTERNOON. ..08..
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 324 PM CDT THU AUG 1 2013
FORECAST FOCUS IS ON PERIODS FOR PRECIPITATION CHANCES AND BELOW
NORMAL TEMPERATURES THROUGH NEXT WEEK.
FRIDAY NIGHT AND SATURDAY...CHANCES FOR SHOWERS AND A FEW
THUNDERSTORMS CONTINUE FRIDAY EVENING AS UPPER SHORTWAVE ENERGY
WORKS ITS WAY ACROSS THE AREA. THE BETTER CHANCES LOOK TO BE ACROSS
THE SOUTHERN FORECAST SECTIONS...AND WILL DIMINISH SATURDAY MORNING
AS THE SHORTWAVE DEPARTS.
SUNDAY THROUGH THURSDAY...SEVERAL SHORTWAVES ARE FORECAST TO MOVE
THROUGH THE CONTINUED NORTHWEST FLOW AND BRING A COUPLE
OPPORTUNITIES FOR SHOWERS AND STORMS. AS CAN BE EXPECTED...FORECAST
MODELS ARE SHOWING QUITE A BIT OF VARIATION IN TIMING AND PLACEMENT
OF THESE SMALLER SCALE FEATURES. THEREFORE CONFIDENCE IN WHICH DAYS
HOLD THE BEST CHANCE FOR PRECIPITATION IS LOW. SEASONABLY COOL
TEMPERATURES WILL CONTINUE WITH HIGHS IN THE MIDDLE 70S TO LOWER 80S
RANGE...AND LOWS IN THE MIDDLE 50S TO LOWER 60S FOR MOST OF THE WEEK.
STOFLET
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1246 PM CDT THU AUG 1 2013
VFR WX IS EXPECTED THROUGH 06Z/02 AS HIGH PRESSURE MOVES EAST INTO
THE GREAT LAKES. A DISTURBANCE ALOFT WILL INITIATE ISOLATED TO
SCATTERED CONVECTION ACROSS EASTERN IOWA JUST PRIOR TO 00Z/02 THAT
MAY BECOME LOOSELY ORGANIZED AFT 00Z/02 WITH SOME TSRA. A BRIEF
PERIOD OF MVFR CONDITIONS MAY BE SEEN IF A SHRA/TSRA AFFECTS A TAF
SITE. AFT 06Z/02 AN ORGANIZED TSRA COMPLEX WILL MOVE INTO EASTERN
IOWA AND ILLINOIS. VFR CONDITIONS ARE FORECAST AFT 06Z/02 BUT THE
POTENTIAL DOES EXIST FOR MVFR/IFR CONDITIONS. ..08..
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
SYNOPSIS...08
SHORT TERM...08
LONG TERM...STOFLET
AVIATION...08
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1256 PM CDT THU AUG 1 2013
.UPDATE...
ISSUED AT 1246 PM CDT THU AUG 1 2013
DEW POINTS HAVE BEEN DROPPING SINCE SUNRISE WHICH EXPLAINS THE
LACK OF DIURNAL CU ACROSS THE AREA. THE VORT MAX IS MAKING GOOD
PROGRESS THROUGH THE DAKOTAS AND SHOULD BE MOVING INTO EASTERN
IOWA BY LATE AFTERNOON/EVENING. THE FACT THAT DEW POINTS ARE
DROPPING MEANS EVAPORATIVE COOLING WILL BE A FACTOR THAT MAY DELAY
THE START OF PRECIPITATION.
TRENDS FROM THE RAP CONTINUE TO SUGGEST LATE AFTERNOON/EVENING
CONVECTION DEVELOPING ACROSS THE AREA THAT MAY BECOME LOOSELY
ORGANIZED DURING THE EVENING. THE DRIER AIR SUGGESTS THE POTENTIAL
FOR SMALL HAIL TONIGHT WITH DISCRETE STORMS THAT HAVE A STRONGER
UPDRAFT.
THE MCS TOOL CONTINUES TO SUGGEST AN ORGANIZED MCS WILL MOVE INTO
THE CWFA LATE TONIGHT WITH POSSIBLY LOCALLY HEAVY RAIN. ..08..
UPDATE ISSUED AT 1008 AM CDT THU AUG 1 2013
SATELLITE HAS A SMALL AMOUNT OF ACCAS FROM ROUGHLY THE MISSISSIPPI
RIVER BACK INTO SOUTHERN MINNESOTA. CONVECTION IS PERSISTING
ACROSS THE PLAINS IN RESPONSE TO THE SHORTWAVE MOVING THROUGH THE
DAKOTAS AND FAR NORTHERN NEBRASKA. THE INVERSION HAS BROKEN
EVIDENT BY THE WIND FARMS DROPPING OFF THE RADAR RETURNS.
QUIET AND DRY CONDITIONS WILL BE SEEN FROM LATE MORNING THROUGH
MID AFTERNOON AS THE WEAK SFC HIGH MOVES EAST OF THE CWFA. THE
APPROACHING SHORTWAVE LATE THIS AFTERNOON AND INTO EARLY EVENING
SHOULD HELP GENERATE ELEVATED SHOWERS AND POSSIBLY A FEW
THUNDERSTORMS THAT MOVE INTO THE NORTHWEST PART OF THE CWFA. ..08..
&&
.SYNOPSIS...
ISSUED AT 246 AM CDT THU AUG 1 2013
ANALYSIS AT 2 AM SHOWS WEAK HIGH PRESSURE OVERHEAD RESULTING IN CALM
WINDS WITH PATCHY SHALLOW GROUND FOG DEVELOPING IN FAVORED LOW LYING
LOCATIONS. WEAK PRESSURE RISE LOBE FROM THE WEST SUGGESTS ANY FOG
TO REMAIN PATCHY THROUGH SUNRISE. STRONG NORTHWEST FLOW PER ANALYSIS
AND ALSO SATELLITE AND UPSTREAM RADARS SUPPORTS GOOD UPGLIDE EVENT
TO ARRIVE ACROSS AREA TONIGHT FROM THE HIGH PLAINS. AREA TEMPERATURES
AND DEWPOINTS IN THE MEANWHILE TODAY SUGGEST ANOTHER WARM BUT
COMFORTABLE DAY. UPSTREAM ANALYSIS SUPPORTS STRONG NORTHWEST FLOW
TO KEEP AREA BELOW NORMAL WITH OCCASIONAL CHANCES OF RAIN THROUGH
NEXT WEEK.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 246 AM CDT THU AUG 1 2013
TODAY...ANOTHER NEAR IDEAL SUMMER DAY WITH MOSTLY SUNNY SKIES AND HIGHS
OF 79-84 DEGREES FROM NORTH TO SOUTH WITH DEWPOINTS IN THE UPPER 50S
TO LOWER 60S. THE MODERATE HUMIDITY AND WESTERLY WINDS OF 5 TO 15 MPH
TO MAKE FOR IDEAL CONDITIONS FOR MANY OUTSIDE ACTIVITIES. SOME ELEVATED
ALTO-CUMULUS MAY DEVELOP IN FAR NORTHWEST SECTIONS TOWARD SUNSET AS
ELEVATED UPPER AIR DISTURBANCE MOVES TOWARD THE REGION.
TONIGHT...SHOWERS TO DEVELOP ACROSS NORTH 1/2 AND BLOOM INTO SHOWERS
AND STORMS AS LOW LEVEL FORCING INCREASES BY EARLY OVERNIGHT HOURS.
WARM ADVECTION WING TOOL INDICATES THE BEST AXIS OF HEAVIER RAINS ARE
SUGGESTED TO BE ROUGHLY ALONG HIGHWAY 30. POPS LIKELY OVER MOST OF
THE REGION TO CHANCE IN SE SECTIONS. FORCING TOOLS ALSO SUGGESTS
HIGHER POPS MAY BE NEEDED AFTER MIDNIGHT AND ALSO HIGHER RAINFALL
AMOUNTS WITH LOCALLY UP TO NEAR 1 INCH AMOUNTS POSSIBLE DUE TO MINOR
TRAINING OF STORMS AND SHOWERS AND PW VALUES WELL OVER 1 INCH. ISOLATED
PEA SIZE HAIL MAY BE POSSIBLE IN STRONGEST STORMS TOWARD SUNRISE FRIDAY.
NICHOLS
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 246 AM CDT THU AUG 1 2013
FORECAST FOCUS ON BELOW NORMAL TEMPERATURES THROUGH AT LEAST THE
MIDDLE OF AUGUST.
FRIDAY INTO SATURDAY...RESPECTABLE WAVE IN THE FLOW WILL CONTINUE TO
TRIGGER SHOWERS AND A FEW THUNDERSTORMS ACROSS MOST OF THE CWA
FRIDAY INTO SATURDAY MORNING. SOME AREAS MAY PICK UP OVER AN INCH OF
RAIN AS PWATS INCREASE TO OVER 1.50 INCHES. HAVE RAISED POPS INTO
THE LIKELY CATEGORY OVER MOST OF THE CWA AS THIS SIGNAL HAS BEEN
PERSISTENT FOR DAYS. MODELS SUGGEST EXTENSIVE CLOUD COVER WILL
REMAIN MUCH OF THE DAY AND THEREFORE HAVE LOWERED TEMPERATURES A
COUPLE OF DEGREES FROM EARLIER FORECAST. THIS WOULD THEN KEEP HIGHS
IN THE UPPER 70S AT MOST LOCATIONS. CHANCES OF RAIN WILL CONTINUE
INTO SATURDAY MORNING BUT MODELS WANT TO DRY THINGS OUT BY AFTERNOON.
SUNDAY THROUGH WEDNESDAY...SEVERAL MORE SIGNIFICANT WAVES IN THE
NORTHWEST FLOW ARRIVES ABOUT SUNDAY NIGHT AND AROUND NEXT WEDNESDAY.
THIS SHOULD BRING MORE OPPORTUNITIES FOR SHOWERS AND THUNDERSTORMS.
HIGHS MAINLY IN THE UPPER 70S TO LOWER 80S AND LOWS IN THE LOWER TO
MID 60S FOR MUCH OF THIS TIME FRAME.
LATE NEXT WEEK THROUGH THE MIDDLE OF AUGUST...THE ECMWF IS BACK WITH
THE POLAR VORTEX DROPPING SOUTHWARD TOWARDS LAKE SUPERIOR AND THEN
PUSHING EASTWARD. THIS WILL REINFORCE THE BELOW NORMAL TEMPERATURES
WITH VERY COOL AIR ONCE AGAIN PLUNGING OUT OF CANADA. THE PATTERN
SEEMS TO FAVOR BELOW NORMAL TEMPERATURES CONTINUING AT LEAST THROUGH
THE MIDDLE OF AUGUST. PRECIPITATION LOOKS TO BE NORMAL TO ABOVE
NORMAL FOR AT LEAST THE FIRST HALF OF THE MONTH.
HAASE
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1246 PM CDT THU AUG 1 2013
VFR WX IS EXPECTED THROUGH 06Z/02 AS HIGH PRESSURE MOVES EAST INTO
THE GREAT LAKES. A DISTURBANCE ALOFT WILL INITIATE ISOLATED TO
SCATTERED CONVECTION ACROSS EASTERN IOWA JUST PRIOR TO 00Z/02 THAT
MAY BECOME LOOSELY ORGANIZED AFT 00Z/02 WITH SOME TSRA. A BRIEF
PERIOD OF MVFR CONDITIONS MAY BE SEEN IF A SHRA/TSRA AFFECTS A TAF
SITE. AFT 06Z/02 AN ORGANIZED TSRA COMPLEX WILL MOVE INTO EASTERN
IOWA AND ILLINOIS. VFR CONDITIONS ARE FORECAST AFT 06Z/02 BUT THE
POTENTIAL DOES EXIST FOR MVFR/IFR CONDITIONS. ..08..
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
UPDATE...08
SYNOPSIS...NICHOLS
SHORT TERM...NICHOLS
LONG TERM...HAASE
AVIATION...08
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
248 PM CDT Thu Aug 1 2013
...Updated long term section...
.SHORT TERM...(Today and tonight)
ISSUED AT 410 AM CDT THU AUG 1 2013
The Latest HRRR model shows an increase in convection across west
central Kansas eastward to the highway 283 corridor. The current
meso alpha convective trends from 88d KPUB suggest at least some
thunderstorm activity could make it to extreme western Kansas
between 9 and 12Z. However there is greater conceive inhibition
indicated by the mesoanalysis as well as a decrease in overall
mucape. As a result we`ll minimize precipitation chances this
morning, relegating small chances to those areas generally west of
highway 83.
As warmer air will be in place in the boundary layer today,
temperatures will be considerably warmer, and likely in the mid
90s in most locations. surface winds will veer to the south with
time and increase to 15-20 knots sustained as mixing develops
during the mid to late morning. The consensus of the NAM WRF and
NMM indicate a better chance for another round of thunderstorms
somewhere across the region late in the afternoon and evening.
confidence is low with respect to where any thunderstorms will
occur, but possibilities exist associated with a cluster
associated with a shortwave to the north, and also across central
ks and the far southwest as convection rolls off the higher
terrain again.
.LONG TERM...(Friday night through Thursday)
ISSUED AT 247 PM CDT THU AUG 1 2013
The extended forecast well consist of multiple disturbances moving
around an upper level high across the Southern United States and
into the Central Plains. These disturbances will enhance lift as
well as increase instability in the mid levels of the atmosphere.
Meanwhile, ample moisture and frontal boundaries at the surface will
create enough lift to create thunderstorms across Western Kansas
periodically throughout the extended period.
A warm front is progged to move north across Southwest Kansas Friday
night into Saturday before stalling out across Northwest and Central
Kansas by Sunday morning. Partly cloudy skies are anticipated early
Saturday morning, increasing and becoming mostly cloudy by Saturday
night. A chance of thunderstorms will be possible along this
boundary, especially late Saturday afternoon into Saturday night
when POPs increase to above 50 percent. A slight chance of
thunderstorms will be possible Sunday along this boundary, but I`m
less confident that they will actually form. Otherwise anticipate
mostly cloudy skies and winds from the east to southeast. Another
fairly good chance of thunderstorms will be possible once again
Monday afternoon into Monday night as an upper level shortwave moves
into the Central Plains. As for temperatures, highs Saturday are
expected to range from the upper 80s across West Central Kansas to
upper 90s across the KS/OK border. Highs Sunday are forecasted to
range from the lower 80s across central Kansas to lower 90s across
the KS/OK border. Lows Saturday morning through Monday morning will
generally range from the upper 60s across West Central Kansas to
lower 70s across South Central Kansas.
The upper level high then shifts farther east into the Lower
Mississippi Valley during the middle of the week as an upper level
long wave trough treks into the Western United States. A few more
shortwaves are progged to move into the Central Plains during this
time bringing additional chances of thunderstorms to Western Kansas.
However, since this is out on day 6 and 7 confidence is low on the
exact position and timing of these thunderstorms. Otherwise expect
partly cloudy skies and winds generally from the east to southeast.
Highs Monday through Wednesday are forecasted to range from the mid
80s across West Central Kansas to lower 90s across the KS/OK border.
Lows Saturday morning through Monday morning will generally range
from the upper 60s across West Central Kansas to lower 70s across
South Central Kansas.
&&
.AVIATION...(For the 18Z TAFS through 18Z Friday afternoon)
ISSUED AT 1250 PM CDT THU AUG 1 2013
A trough of low pressure will remain in the lee of the rockies
through tonight, resulting in south winds at 12-15kts. Isolated
thunderstorms will develop near the Colorado border by 21-23z and
could affect KGCK by 00-02z. On Friday, surface low pressure will
move into northwest Kansas, with winds becoming southwest at 20
kts at the taf sites. VFR conditions will persist outside of
thunderstorms.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 70 102 70 91 / 20 10 20 40
GCK 70 100 69 89 / 20 20 20 40
EHA 70 100 69 93 / 20 10 20 40
LBL 71 103 70 95 / 20 20 20 30
HYS 70 96 70 88 / 50 20 30 50
P28 72 102 73 95 / 20 20 20 30
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...RUSSELL
LONG TERM...HOVORKA_42
AVIATION...FINCH
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
1254 PM CDT Thu Aug 1 2013
...Updated for aviation discussion...
.SYNOPSIS...
ISSUED AT 410 AM CDT THU AUG 1 2013
The 00 utc Thursday objective upper air analysis showed an upper
anticyclone across western TX/eastern NM with an 80 knot jet streak
exiting central Kansas on the east side of the upper ridge. Based
on the 00 utc upper air sounding in combination with he 700 mb
analysis it appears very little change took place in the mid
levels. however, the same analysis showed a marked up tick in
boundary layer temperature, especially at the 850 mb level where
temperatures warmed an average of 5 to 10 degrees.
Regional mosaic 88d reflectivity shows a couple of areas of
decaying MCS/thunderstorms activity, one across the Texas
panhandle and one across east central Colorado. The KGLD 88D
indicates a convective outflow boundary moving southeast across
west central Kansas.
&&
.SHORT TERM...(Today and tonight)
ISSUED AT 410 AM CDT THU AUG 1 2013
The Latest HRRR model shows an increase in convection across west
central Kansas eastward to the highway 283 corridor. The current
meso alpha convective trends from 88d KPUB suggest at least some
thunderstorm activity could make it to extreme western Kansas
between 9 and 12Z. However there is greater conceive inhibition
indicated by the mesoanalysis as well as a decrease in overall
mucape. As a result we`ll minimize precipitation chances this
morning, relegating small chances to those areas generally west of
highway 83.
As warmer air will be in place in the boundary layer today,
temperatures will be considerably warmer, and likely in the mid
90s in most locations. surface winds will veer to the south with
time and increase to 15-20 knots sustained as mixing develops
during the mid to late morning. The consensus of the NAM WRF and
NMM indicate a better chance for another round of thunderstorms
somewhere across the region late in the afternoon and evening.
confidence is low with respect to where any thunderstorms will
occur, but possibilities exist associated with a cluster
associated with a shortwave to the north, and also across central
ks and the far southwest as convection rolls off the higher
terrain again.
.LONG TERM...(Friday through Wednesday)
ISSUED AT 259 AM CDT THU AUG 1 2013
On Friday afternoon the GFS and ECMWF both suggest a weak upper
level wave will move out into the plains with some afternoon
convection being possible near a surface boundary that appears to
extend from west to east across northern Kansas. 850mb warm air
advection still evident along and north of this boundary. We will
therefore retain precipitation chances across north central Kansas
while further south the warm +14/+15c 700mb temperatures and less
moisture will be present which appears to limit precipitation
chance in these locations until possibly early evening when better
instability develops. 850mb temperature trends south of this
boundary continues to support highs warmer than Thursday with the
potential for afternoon highs approaching 100 degrees across
portions of far southwest Kansas. Across north central Kansas the
afternoon temperatures will be more tricky given cloud and
precipitation potential. Given this will stay close to the
previous forecast with highs 7 to near 10 degrees cooler than
southwest Kansas.
A cold front will then move into southwest Kansas on Saturday.
This surface boundary will then remain in western Kansas through
early next week as an upper level trough/low moves out of Canada
and into the the great lakes region. High pressure at the surface
will move out of south central Canada and into the the Ohio
valley. More seasonal temperatures are likely over the weekend
into early next week given the cooler 925-850mb air that is
forecast to return to much of western Kansas. There will also be
chance for convection each day from Saturday through early next
week given the southeasterly upslope flow, higher 925-850mb dewpoints
forecast to be located just east/northeast of this surface
boundary and any subtle upper wave exiting the Rockies and
crossing the plains. Given this potential am unable to improve
much on the latest CRExtendFcst_Init and keep a chance of
precipitation in each period from Sunday into mid week. Warm
nights and seasonal afternoon temperatures also look on track.
&&
.AVIATION...(For the 18Z TAFS through 18Z Friday afternoon)
ISSUED AT 1250 PM CDT THU AUG 1 2013
A trough of low pressure will remain in the lee of the rockies
through tonight, resulting in south winds at 12-15kts. Isolated
thunderstorms will develop near the Colorado border by 21-23z and
could affect KGCK by 00-02z. On Friday, surface low pressure will
move into northwest Kansas, with winds becoming southwest at 20
kts at the taf sites. VFR conditions will persist outside of
thunderstorms.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 94 70 98 69 / 10 50 10 20
GCK 96 70 97 68 / 20 40 20 20
EHA 97 70 98 68 / 20 40 10 20
LBL 96 71 100 69 / 20 40 20 20
HYS 93 70 93 69 / 20 50 20 30
P28 93 72 97 72 / 10 50 20 30
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...RUSSELL
SHORT TERM...RUSSELL
LONG TERM...BURGERT
AVIATION...FINCH
AREA FORECAST DISCUSSION
NWS TOPEKA KS
1225 PM CDT Thu Aug 1 2013
...Update to aviation forecast discussion...
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 336 AM CDT THU AUG 1 2013
Water vapor imagery and 08z RAP analysis shows the H5 ridge over the
desert southwest with a well developed deep trough over the Hudson
Bay. Between these two features northwest flow continues over the
forecast area, with roughly 30 to 40 knots of flow at 500 mb. At the
surface the ridge axis runs from NW to SE across the forecast area,
which is helping to reduce flow at the surface, bringing calm
morning conditions. Through the remainder of the morning a few areas
of patchy fog will form as radiational cooling will be enhanced by
low surface flow and mostly clear skies. Passing cirrus will help
retain some heat at the surface, preventing widespread dense fog,
but considering the moist low levels from recent rain and calm, cool
conditions there will be a marginal fog threat through the remainder
of the morning hours.
Radar trends indicate that a few showers have formed across central
Nebraska, and are moving east/southeastward into south central
Nebraska. The best isentropic/warm air advection upglide can be
found on a decently deep layer between 305 and 315 K Theta E
surfaces. Forecast soundings show about 500 to 1000 J/Kg of elevated
instability above the 700 mb layer, so any parcels that get lifted
to that level will have a chance to form into scattered
thunderstorms later today. The best chance for that scattered
T-storm development will be mainly across central Nebraska,
southward into far northern Kansas, where the best isentropic
upglide persists. Clouds will likely build in, especially north of
Interstate 70, so have gone with a slightly cooler temperature
forecast for the far northern row of counties, but should rain
develop in that area temps may struggle to reach the forecast highs
in the lower to middle 80s.
Warm air advection will continue through the evening and overnight
hours on Thursday night, and as the deeper moisture makes its way
into northeast Kansas the coverage and intensity of the rain showers
will pick up . Expect widespread rain/thunderstorm activity,
especially north of Interstate 70 by early Friday morning, with
perhaps some showers and thunderstorms further south, toward the
Interstate 35 corridor.
.LONG TERM...(Friday THROUGH Wednesday)
ISSUED AT 336 AM CDT THU AUG 1 2013
Friday/Saturday...Expect some thunder to be ongoing Friday as
complex forecast to roll off the high plains across Nebraska then
into eastern Kansas along the thermal gradient and on the nose of
the LLJ. enough instability and shear to make strong to severe
storms possible...as well as steep lapse rates in the low levels
contributing to potential wind threat. despite the dry layer,
precipitable water values over the area remain in the 1.5 to 2
inch range, and must therefore also consider heavy rainfall a
possibility. Storm chances slowly shift eastward into sunrise on
Saturday, and may be able to catch a break during the day
Saturday. Will carry only an isolated pop given boundary resides
right over the forecast area and can`t rule out precip for good
just yet.
Sun/Mon...Stronger and more significant shortwave trof forecast
to come off the central Rockies and into eastern Kansas on Sunday.
Will carry high chance pops and cooler temperatures to reflect
this. subsidence behind this wave may temper precip chances on
Monday and have kept a decrease that time period.
Tues/Wed...Area remains under NW flow aloft with series of waves
dropping surface high pressure into our area early to mid week
next week. If this pattern verifies we would stay cooler than
normal with above average precipitation possible.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z Friday AFTERNOON)
ISSUED AT 1221 PM CDT THU AUG 1 2013
Expect a broken cumulus cloud deck to develop between 3500 and
5000 feet this afternoon and evening. Thunderstorms become more
likely at/near TAF sites after 04Z, as it appears that a
thunderstorm complex may move southeast out of Nebraska and impact
all TAF sites. These storms may persist beyond 12Z, and perhaps as
long as 18Z. Have kept south winds predominant but any tstorms
would cause varying winds, particularly from the north early with
an eventual shift out of the east as the storms pass.
Barjenbruch
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...Leighton
LONG TERM...67
AVIATION...BARJENBRUCH
AREA FORECAST DISCUSSION
NWS TOPEKA KS
634 AM CDT Thu Aug 1 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 336 AM CDT THU AUG 1 2013
Water vapor imagery and 08z RAP analysis shows the H5 ridge over the
desert southwest with a well developed deep trough over the Hudson
Bay. Between these two features northwest flow continues over the
forecast area, with roughly 30 to 40 knots of flow at 500 mb. At the
surface the ridge axis runs from NW to SE across the forecast area,
which is helping to reduce flow at the surface, bringing calm
morning conditions. Through the remainder of the morning a few areas
of patchy fog will form as radiational cooling will be enhanced by
low surface flow and mostly clear skies. Passing cirrus will help
retain some heat at the surface, preventing widespread dense fog,
but considering the moist low levels from recent rain and calm, cool
conditions there will be a marginal fog threat through the remainder
of the morning hours.
Radar trends indicate that a few showers have formed across central
Nebraska, and are moving east/southeastward into south central
Nebraska. The best isentropic/warm air advection upglide can be
found on a decently deep layer between 305 and 315 K Theta E
surfaces. Forecast soundings show about 500 to 1000 J/Kg of elevated
instability above the 700 mb layer, so any parcels that get lifted
to that level will have a chance to form into scattered
thunderstorms later today. The best chance for that scattered
T-storm development will be mainly across central Nebraska,
southward into far northern Kansas, where the best isentropic
upglide persists. Clouds will likely build in, especially north of
Interstate 70, so have gone with a slightly cooler temperature
forecast for the far northern row of counties, but should rain
develop in that area temps may struggle to reach the forecast highs
in the lower to middle 80s.
Warm air advection will continue through the evening and overnight
hours on Thursday night, and as the deeper moisture makes its way
into northeast Kansas the coverage and intensity of the rain showers
will pick up . Expect widespread rain/thunderstorm activity,
especially north of Interstate 70 by early Friday morning, with
perhaps some showers and thunderstorms further south, toward the
Interstate 35 corridor.
.LONG TERM...(Friday THROUGH Wednesday)
ISSUED AT 336 AM CDT THU AUG 1 2013
Friday/Saturday...Expect some thunder to be ongoing Friday as
complex forecast to roll off the high plains across Nebraska then
into eastern Kansas along the thermal gradient and on the nose of
the LLJ. enough instability and shear to make strong to severe
storms possible...as well as steep lapse rates in the low levels
contributing to potential wind threat. despite the dry layer,
precipitable water values over the area remain in the 1.5 to 2
inch range, and must therefore also consider heavy rainfall a
possibility. Storm chances slowly shift eastward into sunrise on
Saturday, and may be able to catch a break during the day
Saturday. Will carry only an isolated pop given boundary resides
right over the forecast area and can`t rule out precip for good
just yet.
Sun/Mon...Stronger and more significant shortwave trof forecast
to come off the central Rockies and into eastern Kansas on Sunday.
Will carry high chance pops and cooler temperatures to reflect
this. subsidence behind this wave may temper precip chances on
Monday and have kept a decrease that time period.
Tues/Wed...Area remains under NW flow aloft with series of waves
dropping surface high pressure into our area early to mid week
next week. If this pattern verifies we would stay cooler than
normal with above average precipitation possible.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z Friday MORNING)
ISSUED AT 626 AM CDT THU AUG 1 2013
Expect morning fog near the aviation terminals to gradually clear
out as the sun rises. After that expect mostly VFR conditions at
the terminals. There is some uncertainty regarding afternoon
showers and thunderstorms. Generally they are expected to remain
north of the terminals, near the KS/NE border, however a few
showers may form along Interstate 70, perhaps putting the
terminals in play for afternoon showers. The best chance for rain
near the TAF site will be at KMHK, but even that probability is
low at this time. Will reassess shower potential with upcoming
issuance or with AMD should the need arise.
JL
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...Leighton
LONG TERM...67
AVIATION...LEIGHTON
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
607 AM CDT Thu Aug 1 2013
...Updated aviation discussion...
.SYNOPSIS...
ISSUED AT 410 AM CDT THU AUG 1 2013
The 00 utc Thursday objective upper air analysis showed an upper
anticyclone across western TX/eastern NM with an 80 knot jet streak
exiting central Kansas on the east side of the upper ridge. Based
on the 00 utc upper air sounding in combination with he 700 mb
analysis it appears very little change took place in the mid
levels. however, the same analysis showed a marked up tick in
boundary layer temperature, especially at the 850 mb level where
temperatures warmed an average of 5 to 10 degrees.
Regional mosaic 88d reflectivity shows a couple of areas of
decaying MCS/thunderstorms activity, one across the Texas
panhandle and one across east central Colorado. The KGLD 88D
indicates a convective outflow boundary moving southeast across
west central Kansas.
&&
.SHORT TERM...(Today and tonight)
ISSUED AT 410 AM CDT THU AUG 1 2013
The Latest HRRR model shows an increase in convection across west
central Kansas eastward to the highway 283 corridor. The current
meso alpha convective trends from 88d KPUB suggest at least some
thunderstorm activity could make it to extreme western Kansas
between 9 and 12Z. However there is greater conceive inhibition
indicated by the mesoanalysis as well as a decrease in overall
mucape. As a result we`ll minimize precipitation chances this
morning, relegating small chances to those areas generally west of
highway 83.
As warmer air will be in place in the boundary layer today,
temperatures will be considerably warmer, and likely in the mid
90s in most locations. surface winds will veer to the south with
time and increase to 15-20 knots sustained as mixing develops
during the mid to late morning. The consensus of the NAM WRF and
NMM indicate a better chance for another round of thunderstorms
somewhere across the region late in the afternoon and evening.
confidence is low with respect to where any thunderstorms will
occur, but possibilities exist associated with a cluster
associated with a shortwave to the north, and also across central
ks and the far southwest as convection rolls off the higher
terrain again.
.LONG TERM...(Friday through Wednesday)
ISSUED AT 259 AM CDT THU AUG 1 2013
On Friday afternoon the GFS and ECMWF both suggest a weak upper
level wave will move out into the plains with some afternoon
convection being possible near a surface boundary that appears to
extend from west to east across northern Kansas. 850mb warm air
advection still evident along and north of this boundary. We will
therefore retain precipitation chances across north central Kansas
while further south the warm +14/+15c 700mb temperatures and less
moisture will be present which appears to limit precipitation
chance in these locations until possibly early evening when better
instability develops. 850mb temperature trends south of this
boundary continues to support highs warmer than Thursday with the
potential for afternoon highs approaching 100 degrees across
portions of far southwest Kansas. Across north central Kansas the
afternoon temperatures will be more tricky given cloud and
precipitation potential. Given this will stay close to the
previous forecast with highs 7 to near 10 degrees cooler than
southwest Kansas.
A cold front will then move into southwest Kansas on Saturday.
This surface boundary will then remain in western Kansas through
early next week as an upper level trough/low moves out of Canada
and into the the great lakes region. High pressure at the surface
will move out of south central Canada and into the the Ohio
valley. More seasonal temperatures are likely over the weekend
into early next week given the cooler 925-850mb air that is
forecast to return to much of western Kansas. There will also be
chance for convection each day from Saturday through early next
week given the southeasterly upslope flow, higher 925-850mb dewpoints
forecast to be located just east/northeast of this surface
boundary and any subtle upper wave exiting the Rockies and
crossing the plains. Given this potential am unable to improve
much on the latest CRExtendFcst_Init and keep a chance of
precipitation in each period from Sunday into mid week. Warm
nights and seasonal afternoon temperatures also look on track.
&&
.AVIATION...(For the 12Z TAFS through 12Z Friday morning)
ISSUED AT 605 AM CDT THU AUG 1 2013
A shallow layer of near surface moisture is forecast to be
present for a few hours this morning. Given this along with the
11z observations will introduce a brief period of 4-5sm br early
this morning. after this vfr conditions are expected as mid- high
level moisture begins to increase from west to east. Precipitation
chances will begin to increase early tonight with the better
opportunity for thunder being in the hays area between 03z and 09z
Friday. South winds will increase to near 20kts by the late
afternoon.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 94 70 98 69 / 10 50 10 20
GCK 96 70 97 68 / 20 40 20 20
EHA 97 70 98 68 / 20 40 10 20
LBL 96 71 100 69 / 20 40 20 20
HYS 93 70 93 69 / 20 50 20 30
P28 93 72 97 72 / 10 50 20 30
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...RUSSELL
SHORT TERM...RUSSELL
LONG TERM...BURGERT
AVIATION...BURGERT
AREA FORECAST DISCUSSION
NWS TOPEKA KS
429 AM CDT Thu Aug 1 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 336 AM CDT THU AUG 1 2013
Water vapor imagery and 08z RAP analysis shows the H5 ridge over the
desert southwest with a well developed deep trough over the Hudson
Bay. Between these two features northwest flow continues over the
forecast area, with roughly 30 to 40 knots of flow at 500 mb. At the
surface the ridge axis runs from NW to SE across the forecast area,
which is helping to reduce flow at the surface, bringing calm
morning conditions. Through the remainder of the morning a few areas
of patchy fog will form as radiational cooling will be enhanced by
low surface flow and mostly clear skies. Passing cirrus will help
retain some heat at the surface, preventing widespread dense fog,
but considering the moist low levels from recent rain and calm, cool
conditions there will be a marginal fog threat through the remainder
of the morning hours.
Radar trends indicate that a few showers have formed across central
Nebraska, and are moving east/southeastward into south central
Nebraska. The best isentropic/warm air advection upglide can be
found on a decently deep layer between 305 and 315 K Theta E
surfaces. Forecast soundings show about 500 to 1000 J/Kg of elevated
instability above the 700 mb layer, so any parcels that get lifted
to that level will have a chance to form into scattered
thunderstorms later today. The best chance for that scattered
T-storm development will be mainly across central Nebraska,
southward into far northern Kansas, where the best isentropic
upglide persists. Clouds will likely build in, especially north of
Interstate 70, so have gone with a slightly cooler temperature
forecast for the far northern row of counties, but should rain
develop in that area temps may struggle to reach the forecast highs
in the lower to middle 80s.
Warm air advection will continue through the evening and overnight
hours on Thursday night, and as the deeper moisture makes its way
into northeast Kansas the coverage and intensity of the rain showers
will pick up . Expect widespread rain/thunderstorm activity,
especially north of Interstate 70 by early Friday morning, with
perhaps some showers and thunderstorms further south, toward the
Interstate 35 corridor.
.LONG TERM...(Friday THROUGH Wednesday)
ISSUED AT 336 AM CDT THU AUG 1 2013
Friday/Saturday...Expect some thunder to be ongoing Friday as
complex forecast to roll off the high plains across Nebraska then
into eastern Kansas along the thermal gradient and on the nose of
the llj. enough instability and shear to make strong to severe
storms possible...as well as steep lapse rates in the low levels
contributing to potential wind threat. despite the dry layer,
precipitable water values over the area remain in the 1.5 to 2
inch range, and must therefore also consider heavy rainfall a
possibility. Storm chances slowly shift eastward into sunrise on
Saturday, and may be able to catch a break during the day
Saturday. Will carry only an isolated pop given boundary resides
right over the forecast area and can`t rule out precip for good
just yet.
Sun/Mon...Stronger and more significant shortwave trof forecast
to come off the central Rockies and into eastern Kansas on Sunday.
Will carry high chance pops and cooler temperatures to reflect
this. subsidence behind this wave may temper precip chances on
Monday and have kept a decrease that time period.
Tues/Wed...Area remains under NW flow aloft with series of waves
dropping surface high pressure into our area early to mid week
next week. If this pattern verifies we would stay cooler than
normal with above average precipitation possible.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z Thursday NIGHT)
ISSUED AT 1142 PM CDT WED JUL 31 2013
There is not much change from previous forecast thinking. With
cirrus overspreading from the west...it may be that much more
difficult for ground fog to form. Additionally the 00z models
continue to focus the better low level moisture convergence to the
north of the terminals through the day Thursday. Therefore have
left mention if TS out of the forecast with models showing the
best vertical motion and low level convergence after 06z Friday
when the low level jet increases.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...Leighton
LONG TERM...67
AVIATION...WOLTERS
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
416 AM CDT Thu Aug 1 2013
.SYNOPSIS...
ISSUED AT 410 AM CDT THU AUG 1 2013
The 00 utc Thursday objective upper air analysis showed an upper
anticyclone across western TX/eastern NM with an 80 knot jet streak
exiting central Kansas on the east side of the upper ridge. Based
on the 00 utc upper air sounding in combination with he 700 mb
analysis it appears very little change took place in the mid
levels. however, the same analysis showed a marked up tick in
boundary layer temperature, especially at the 850 mb level where
temperatures warmed an average of 5 to 10 degrees.
Regional mosaic 88d reflectivity shows a couple of areas of
decaying MCS/thunderstorms activity, one across the Texas
panhandle and one across east central Colorado. The KGLD 88D
indicates a convective outflow boundary moving southeast across
west central Kansas.
&&
.SHORT TERM...(Today and tonight)
ISSUED AT 410 AM CDT THU AUG 1 2013
The Latest HRRR model shows an increase in convection across west
central Kansas eastward to the highway 283 corridor. The current
meso alpha convective trends from 88d KPUB suggest at least some
thunderstorm activity could make it to extreme western Kansas
between 9 and 12Z. However there is greater conceive inhibition
indicated by the mesoanalysis as well as a decrease in overall
mucape. As a result we`ll minimize precipitation chances this
morning, relegating small chances to those areas generally west of
highway 83.
As warmer air will be in place in the boundary layer today,
temperatures will be considerably warmer, and likely in the mid
90s in most locations. surface winds will veer to the south with
time and increase to 15-20 knots sustained as mixing develops
during the mid to late morning. The consensus of the NAM WRF and
NMM indicate a better chance for another round of thunderstorms
somewhere across the region late in the afternoon and evening.
confidence is low with respect to where any thunderstorms will
occur, but possibilities exist associated with a cluster
associated with a shortwave to the north, and also across central
ks and the far southwest as convection rolls off the higher
terrain again.
.LONG TERM...(Friday through Wednesday)
ISSUED AT 259 AM CDT THU AUG 1 2013
On Friday afternoon the GFS and ECMWF both suggest a weak upper
level wave will move out into the plains with some afternoon
convection being possible near a surface boundary that appears to
extend from west to east across northern Kansas. 850mb warm air
advection still evident along and north of this boundary. We will
therefore retain precipitation chances across north central Kansas
while further south the warm +14/+15c 700mb temperatures and less
moisture will be present which appears to limit precipitation
chance in these locations until possibly early evening when better
instability develops. 850mb temperature trends south of this
boundary continues to support highs warmer than Thursday with the
potential for afternoon highs approaching 100 degrees across
portions of far southwest Kansas. Across north central Kansas the
afternoon temperatures will be more tricky given cloud and
precipitation potential. Given this will stay close to the
previous forecast with highs 7 to near 10 degrees cooler than
southwest Kansas.
A cold front will then move into southwest Kansas on Saturday.
This surface boundary will then remain in western Kansas through
early next week as an upper level trough/low moves out of Canada
and into the the great lakes region. High pressure at the surface
will move out of south central Canada and into the the Ohio
valley. More seasonal temperatures are likely over the weekend
into early next week given the cooler 925-850mb air that is
forecast to return to much of western Kansas. There will also be
chance for convection each day from Saturday through early next
week given the southeasterly upslope flow, higher 925-850mb dewpoints
forecast to be located just east/northeast of this surface
boundary and any subtle upper wave exiting the Rockies and
crossing the plains. Given this potential am unable to improve
much on the latest CRExtendFcst_Init and keep a chance of
precipitation in each period from Sunday into mid week. Warm
nights and seasonal afternoon temperatures also look on track.
&&
.AVIATION...(For the 06Z TAFS through 06Z Thursday evening) ISSUED
AT 630 PM CDT WED JUL 31 2013
Vfr conditions are expected for the next 12-18 hours before better
chances for organized thudnerstorms again redevelop. An increased
surface pressure gradient will allow southerly winds to redevelop
by 15 z at 15 to 20 mph with higer surface gusts.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 94 70 98 69 / 10 50 10 20
GCK 96 70 97 68 / 20 40 20 20
EHA 97 70 98 68 / 20 40 10 20
LBL 96 71 100 69 / 20 40 10 20
HYS 93 70 93 69 / 20 50 30 30
P28 93 72 97 72 / 10 50 20 20
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...RUSSELL
SHORT TERM...RUSSELL
LONG TERM...BURGERT
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1154 PM MDT WED JUL 31 2013
.UPDATE...
ISSUED AT 915 PM MDT WED JUL 31 2013
DUE TO SEVERE CONVECTION COMING TO AN END HAVE CANCELLED THE WATCH
EARLY. ADJUSTED PREICP. CHANCES TO ACCOUNT FOR THE AREA OF
CONVECTION THAT WILL MOVE INTO EAST CENTRAL CO AROUND MIDNIGHT.
OTHERWISE THOUGHTS FROM THE PREVIOUS UPDATE REMAIN UNCHANGED.
UPDATE ISSUED AT 809 PM MDT WED JUL 31 2013
STRONG/SEVERE THUNDERSTORMS HAVE DEVELOPED OVER YUMA COUNTY EAST
INTO CHEYENNE COUNTY KS. INITIALLY STORMS WERE TRIGGERED BY AN
OUTFLOW BOUNDARY FROM EARLIER CONVECTION TO THE SOUTH. THE STORMS
SEEM TO BE SUSTAINED BY THE STRENGTHENING LOW LEVEL JET AND A
SHORT WAVE TROUGH AT 500MB. FURTHER WEST AN AREA OF CONVECTION IS
MOVING TOWARD THE AREA WITH THE UPPER LEVEL TROUGH. AS THE NIGHT
PROGRESSES AM ANTICIPATING THE STORM GROUPS TO POSSIBLY MERGE AS
THEY MOVE TO THE EAST. AS A RESULT HAVE INCREASED PRECIP. CHANCES
FOR THE NIGHT AND SPEED UP THE TIME OF THE BEST CHANCES. STILL
WENT ON THE CONSERVATIVE SIDE LATE IN THE EVENING AND OVERNIGHT SINCE
THERE IS SOME UNCERTAINTY AS TO WHERE EXACTLY THE STORMS WILL
TRACK...BUT IN GENERAL THE NORTHERN HALF OF THE AREA LOOKS TO HAVE
THE BEST SHOT.
&&
.SHORT TERM...(THIS AFTERNOON THROUGH TONIGHT)
ISSUED AT 116 PM MDT WED JUL 31 2013
LATEST WV IMAGERY AND RAP H5 ANALYSIS SHOWS AMPLIFIED RIDGE ACROSS
THE INTER-MOUNTAIN WEST WITH NW FLOW IN PLACE ACROSS THE HIGH
PLAINS. AT THE SURFACE A COLD FRONT IS CURRENTLY IN PLACE ACROSS
CENTRAL NEBRASKA WITH SEVERAL AREAS OF WEAK CONVERGENCE ALONG A PRE
FRONTAL TROUGH THROUGH THE CENTRAL PART OF OUR CWA...AND POSSIBLY
SEVERAL OTHER WEAK SURFACE FEATURES ASSOCIATED WITH OLD OUTFLOW FROM
OVERNIGHT CONVECTION IN THE EAST.
LATEST RAP ANALYSIS INDICATES SBCAPE IN EXCESS OF 3000 J/KG...AND
PWAT VALUES 1-1.5 INCHES ACROSS OUR CWA. THIS VERY MOIST AND
UNSTABLE AIR MASS HAS COMBINED WITH PREVIOUSLY MENTIONED SURFACE
FEATURES TO DEVELOPMENT OF SEVERAL ISOLATED THUNDERSTORMS ACROSS
THE SOUTHERN PART OF OUR CWA. WITH CU FIELD IN PLACE AND
FORCING INCREASING AHEAD OF APPROACHING COLD FRONT I WOULD
ANTICIPATE THUNDERSTORM COVERAGE TO INCREASE THROUGH THIS
AFTERNOON. RAP ALSO INDICATES 0-6KM BULK SHEER IN EXCESS OF 40KT
ACROSS THE SOUTHEASTERN HALF OF OUR CWA...AND WITH LLJ INCREASING
AROUND 00Z I WOULD EXPECT SHEER TO ONLY INCREASE. WHILE I AM
MAINLY ANTICIPATING HAIL/WIND/MULTI-CELL THREAT THROUGH
TONIGHT...TORNADOES COULDNT BE RULED OUT WITH SUPERCELLS THAT
DEVELOP CONSIDERING THE LARGE SCALE SHEER PROFILES. A SEVERE
THUNDERSTORM WATCH HAS ALREADY BEEN ISSUED FOR THE SOUTHERN HALF
OF OUR CWA...AND IF ADDITIONAL ACTIVITY DEVELOPS FURTHER NORTH OF
WATCH WE MAY NEED TO DO A LOCAL EXPANSION CONSIDERING THE
ENVIRONMENT.
WITH 0-6KM STORM MOTION GENERALLY TO THE SOUTHEAST MOST ACTIVITY
SHOULD BE TRANSITIONING OUT OF OUR CWA THIS EVENING...THOUGH WITH
GOOD THETA-E CONVERGENCE AHEAD OF LLJ WE SHOULD SEE ADDITIONAL
DEVELOPMENT TONIGHT ESPECIALLY ACROSS THE NORTHEAST.
.LONG TERM...(TOMORROW THROUGH WEDNESDAY)
ISSUED AT 1244 PM MDT WED JUL 31 2013
THE UPPER PATTERN THIS PERIOD WILL FEATURE A RIDGE CENTERED OVER
TEXAS AND OCCASIONAL SHORTWAVE TROUGHS MOVING OUT OF THE CENTRAL
AND NORTHERN ROCKIES ACROSS THE PLAINS. THIS MEANS THE SAME OLD
STORY THAT HAS BEEN RUNNING A FEW WEEKS NOW: DAILY CHANCES FOR
SHOWERS AND THUNDERSTORMS AND TEMPERATURES NEAR NORMAL. MESOSCALE
DETAILS WILL ULTIMATELY PLAY A LARGE ROLE IN DETERMINING WHERE
BETTER THUNDERSTORM CHANCES WILL BE ON ANY GIVEN DAY...BUT THEY
ARE DIFFICULT TO PREDICT BEYOND A DAY OR TWO AT BEST. AS A
RESULT...POPS WILL BE RATHER BROADBRUSHED ACROSS THE AREA. ON
THURSDAY...SEVERE STORMS WILL BE POSSIBLE GIVEN SUFFICIENT
INSTABILITY AND FAVORABLE SHEAR PROFILES. SEVERE POTENTIAL FOR THE
REMAINDER OF THE PERIOD WILL BE TIED TO SHORTWAVE IMPULSES WITH
LOW PREDICTABILITY AT THIS TIME RANGE.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1144 PM MDT WED JUL 31 2013
VFR CONDITIONS FORECAST FOR THE 6Z TAFS. AREA OF
SHOWERS/THUNDERSTORMS CONTINUES TO TRACK EASTWARD AHEAD OF AN
UPPER LEVEL SHORT WAVE TROUGH. AM ANTICIPATING THE STORMS TO LAST
INTO KS THEN DISSIPATE NOT LONG AFTERWARD. LATER ON ANOTHER SHORT
WAVE TROUGH WILL MOVE OVER THE NORTHEASTERN PART OF THE AREA LATE
TONIGHT...HAVE A TEMPO GROUP FOR KMCK AS A RESULT. STORMS SHOULD BE
OUT OF THE AREA BY MID MORNING. DURING THE MID TO LATE AFTERNOON
STORMS WILL DEVELOP FROM WEST TO EAST ACROSS THE TRI-STATE
AREA...WITH THE BEST CHANCE FOR STORMS DURING THE EVENING OVER
THE EASTERN PART OF THE AREA.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...JTL
SHORT TERM...DR
LONG TERM...024
AVIATION...JTL
AREA FORECAST DISCUSSION
NWS PADUCAH KY
645 PM CDT Fri Aug 2 2013
.UPDATE...
ISSUED AT 645 PM CDT FRI AUG 2 2013
The aviation section has been updated for the 00Z TAF issuance.
&&
.SHORT TERM...(This Evening through Sunday night)
ISSUED AT 204 PM CDT FRI AUG 2 2013
A mid level wave was seen on satellite and via radar moving across
west Missouri. Convection has formed with this wave and was moving
east. Question is, how far east will it travel over the next
several hours, as it encounters drier air across the region. Will
gradually increase pops through the night. None of the models seem
to have a good handle on convective trends. The latest RAP model
is probably closest. Given low confidence in the latest solutions,
will not stray too far from persistence.
Even after a morning chance of convection, the probability for
more development will persist as a frontal boundary sags south
through the area late. Then, will decrease PoPs from north to
south Saturday night and focus them over the west and south into
Sunday and Sunday night.
Temperatures will be a combination of the latest MAV/MET MOS and
a blend of raw model output.
.LONG TERM...(Monday through Friday)
ISSUED AT 204 PM CDT FRI AUG 2 2013
For the beginning of the extended forecast period, namely Monday and
Tuesday, there has been a little less confidence on the eastward
extent of measurable PoP`s. During the last three days, attempted to
highlight the southwestern part of the WFO PAH county warning area,
namely southeast Missouri for rain chances. The low level surface
winds/moisture convergence appears pinned to southeast Missouri
through at least 12z (7am CDT) Tuesday. Although the SREF, GFS, and
ECMWF model precipitation parametrization schemes vary, the low
level frontal zones are similar during the aforementioned time
period. Given the lack if identifiable and consistent vorticity
advection above the frontal boundary, the decision was to limit the
precipitation chances close to the boundary, plus or minus 50 nm.
By late Tuesday night into Wednesday, the southern plains ridge
builds northward, shifting and sharpening the baroclinic zone and
frontal boundary further to the north. With this in mind, the higher
rain chances are shifted into southern Illinois, southwest Indiana,
and west Kentucky. This pattern remains intact through at least
Wednesday afternoon, when the upper ridge begins to flatten and
shift eastward across the lower Mississippi River valley. This
subtle pattern change, combined with a sharper meridional gradient
flow in the faster west to east flow, should lead to a much greater
tightening of the frontal boundary through the WFO PAH forecast area
next Thursday into Friday. Attempted to show a southward shift in
focus of higher PoP`s into toward the Arkansas and Tennessee borders
during this time period. It is also at this time that the highest
PoPs in the extended forecast period should be expected in the WFO
PAH forecast area.
Tuesday through next Friday will likely see max/min temperatures
approach or tie normals for this time of year, as the forecast area
is fully enveloped in the warm sector. With variable cloud cover,
heat index values should remain in check for most of next week. The
only exception may be next Wednesday afternoon, when heat index
values around 100 degrees may be possible along the southern border
counties of southeast Missouri.
&&
.AVIATION...
ISSUED AT 645 PM CDT FRI AUG 2 2013
Kept the forecast VFR, despite multiple opportunities for showers
or even thunderstorms during the period.
Current radar shows a mass of showers over the St Louis Metro
area which is moving east southeast toward KEVV and KOWB, as well
as more scattered showers and storms over southeast Missouri. Feel
that KEVV and KOWB are most likely to get wet this evening, so
introduced a TEMPO group with 6SM SHRA for mid to late evening.
Lots of showers and storms have vaporized as they moved into
southeast Missouri so far, so will only insert sprinkles for a few
hours at the beginning of the period at KCGI just in case some
make it there before completely dissipating. Kept KPAH dry this
evening, but cannot rule out a few sprinkles.
Most guidance indicates that some more showers or even storms will
try to move in just ahead of a weak frontal boundary late tonight
into Saturday morning. Guidance is not in agreement in where the
best chances are or even if all locations will have much of a
chance. Will have to watch the radar out west closely this
evening, and will hopefully have a better clue for the 06Z TAFs.
For now just went with a prevailing lower VFR ceiling and a VCSH
at all sites generally straddling 12Z.
The aforementioned surface front will sort of ooze southward
through the area Saturday. Few models, and none of the higher-
resolution models generate much convection near it during the day,
so will keep the forecast dry after the morning stuff moves out.
Winds will be tricky though. Looks like a modest west or even west
northwest wind may mix down near and ahead of it, with more
northerly flow developing late in the afternoon as the surface
high begins to build into the area. All winds should be under
10kts, but the directions are in doubt through the day. A light
south wind is expected throughout the area tonight.
&&
.PAH WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
MO...NONE.
IN...NONE.
KY...NONE.
&&
$$
UPDATE...DRS
SHORT TERM...Noles
LONG TERM...Smith
AVIATION...DRS
AREA FORECAST DISCUSSION
NWS JACKSON KY
220 AM EDT THU AUG 1 2013
.UPDATE...
ISSUED AT 220 AM EDT THU AUG 1 2013
EXCEPT FOR SOME ISOLATED SHOWERS AT THE VA BORDER...PRECIP HAS ENDED
ACROSS THE FORECAST AREA. HOWEVER...THERE WERE A FEW SHOWERS AND
THUNDERSTORMS WHICH HAVE POPPED UP ALONG THE COLD FRONT MOVING
SOUTHEAST THROUGH SE INDIANA AND SW OHIO. THE RUC AND HRRR SHOW THESE
DIMINISHING SOMEWHAT AS THEY ARRIVE IN OUR NW COUNTIES AROUND
DAWN...BUT SHOW AN INCREASE IN ACTIVITY ALONG THE BOUNDARY AS IT
MOVES SE THROUGH THE FORECAST AREA DURING DAYTIME HEATING. HAVE
UPDATED THE FORECAST TO REFLECT THIS...WITH POPS LIMITED TO 20
PERCENT.
UPDATE ISSUED AT 1050 PM EDT WED JUL 31 2013
UPDATED THE GRIDS TO REFINE POPS THROUGH THE REST OF THE NIGHT...BUT
ALSO KEPT IN THE DRIZZLE PATCHES AND THE FOG. HOURLY TEMPS AND
DEW POINTS WERE TWEAKED BASED ON CURRENT CONDITIONS AND OBS. THE
FORECAST WAS MOSTLY ON TRACK WITH THIS ZFP UPDATE PRIMARILY TO REMOVE
EVENING WORDING. UPDATES HAVE BEEN SENT TO THE NDFD AND WEB SERVERS
WITH THE ZFP TO FOLLOW SHORTLY.
UPDATE ISSUED AT 640 PM EDT WED JUL 31 2013
22Z SFC ANALYSIS SHOWS A WEAK AREA OF LOW PRESSURE MOVING THROUGH
KENTUCKY. THIS HAS BROUGHT PLENTY OF LOW CLOUDS AND LIGHT PCPN TO THE
AREA TODAY RESULTING IN HIGH TEMPERATURES ONLY ON THE LOW 70S...FOR
MOST PLACES. THIS MEANT A DAY THAT SEEMED CLOSER TO EARLY OCTOBER
THAN THE LAST DAY OF JULY. THE SHOWERS HAVE DIMINISHED TO JUST A FEW
PATCHES CROSSING FAR SOUTHEAST PARTS OF THE AREA...THOUGH PATCHY
DRIZZLE AND AREAS OF FOG REMAIN BEHIND. EXPECT THE SMALL RAIN CHANCES
TO CONTINUE THROUGH THE NIGHT WHILE THE LOW MOVES OVER EAST
KENTUCKY...BUT THE SHOWERS OF ANY SIGNIFICANCE ARE DONE. HAVE
ADJUSTED THE POPS...WX AND SKY FOR THE REST OF THE NIGHT WHILE ALSO
MAKING MORE FINE TUNE TWEAKS TO THE TEMPERATURES AND DEW POINTS GRIDS
PER LATEST OBS AND TRENDS. THE UPDATED GRIDS HAVE BEEN SENT TO THE
NDFD AND WEB SERVERS ALONG WITH A FRESHENED ZFP AND HWO.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY NIGHT)
ISSUED AT 312 PM EDT WED JUL 31 2013
THE MODELS ARE IN GOOD AGREEMENT AS A SHORT WAVE AND FRONT MOVE
ACROSS THE AREA. THE PREVIOUS MODELS SHOWED A WHOLE LOT MORE
PRECIPITATION DEVELOPING OVER THE AREA THAN WHAT HAS OCCURRED IN THE
LAST 8 HOURS. THE MODELS WERE SHOWING A MUCH MORE VIGOROUS SYSTEM
DEVELOPING AND WERE SHOWING A LOW MOVING ACROSS EASTERN KENTUCKY. THE
LOW ACTUALLY HAS PASSED FURTHER TO THE SOUTH AND HAS MOVED ACROSS
TENNESSEE INSTEAD HAS SUCH...THE HEAVIER RAIN HAS STAYED SOUTH OF
JACKSON. THE NAM WAS SHOWING A LARGE MASS OF RAIN MOVING ACROSS THE
AREA THIS EVENING...HOWEVER DOUBT IS STARTING TO CREEP IN WHETHER IT
WILL AMOUNT TO MORE THAT THAN A LITTLE DRIZZLE. THE LAST UPDATE
AROUND 2 PM...ALREADY BACK THE PROBABILITY OF PRECIPITATION DOWN AND
KEPT THE BEST CHANCES SOUTH OF JACKSON. TOMORROW SHOULD JUST SEE OF
ISOLATED THE SCATTERED SHOWERS WILL LITTLE OR NO ACCUMULATION. WITH
THE CLOUD COVER...EXPECT TEMPERATURES TO STAY BELOW NORMAL THROUGH
THE END OF THE PERIOD.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 312 PM EDT WED JUL 31 2013
THERE IS GOOD MODEL AGREEMENT ON THE GENERAL PATTERN THROUGH THE
MIDDLE OF NEXT WEEK...BUT SIGNIFICANT DIFFERENCES IN THE DETAILS
DEVELOP AFTER THIS WEEKEND. THE OVERALL PATTERN...WHICH HAS BEEN THE
CASE FOR MUCH OF THIS SUMMER...REMAINS IN PLACE...WITH RIDGING IN
THE WESTERN U.S. AND TROUGHING IN THE EAST. AS SUCH TEMPERATURES
WILL CONTINUE TO AVERAGE BELOW NORMAL. A SHORT WAVE MOVING ACROSS
THE GREAT LAKES AND OH VALLEY THIS WEEKEND WILL HELP DRIVE A COLD
FRONT SOUTH ACROSS THE REGION...WITH LATEST GUIDANCE INDICATING THE
FRONT SHOULD BE SOUTH OF KY BY 12Z SUNDAY. AS SUCH PRECIPITATION
CHANCES STILL LOOK TO BE HIGHEST FROM SATURDAY INTO SATURDAY NIGHT
DURING THE UPCOMING WEEKEND.
AFTER THE WEEKEND SIGNIFICANT DIFFERENCES DEVELOP WITH HOW DEEP THE
EASTERN TROUGH BECOMES...AND HOW FAR SOUTH THE SURFACE COLD FRONT
ENDS UP BEFORE STALLING OUT. THE 00Z ECMWF HAS A MUCH DEEPER EASTERN
TROUGH WITH THE COOL AIR DRIVING WELL SOUTH...WITH THE BEST
PRECIPITATION CHANCES NEXT WEEK REMAINING TO OUR SOUTH AS WELL. THE 12Z
GFS AND 12Z GEM DO NOT HAVE THE TROUGH AS DEEP...AND ALSO INDICATE
BETTER PRECIPITATION CHANCES FOR EARLY NEXT WEEK. THE LATEST WPC
GUIDANCE ALSO KEEPS THE SURFACE FRONTAL BOUNDARY IN THE VICINITY OF
THE TN VALLEY FOR THE FIRST HALF OF NEXT WEEK. SPECIFIC TEMPERATURE
FORECASTS REALLY SHOW THE EXTREME MODEL DIFFERENCES. FOR 12Z WED
AUGUST 7 THE 00Z ECMWF SHOWS 8H TEMPERATURES FROM 11 TO 12 C
ACROSS E KY...WHILE THE 12Z GFS SHOWS 8H TEMPERATURES FROM 18 TO 20
C. NOT SURPRISINGLY THE GFS MOS TEMPERATURE GUIDANCE BY THE MIDDLE
OF NEXT WEEK IS AROUND 10 DEGREES F WARMER THEN THE ECMWF MOS
GUIDANCE....WITH THE GFS GUIDANCE ACTUALLY INDICATING ABOVE NORMAL
TEMPERATURES. EVEN IF THE GENERAL UPPER AIR PATTERN FORECAST BY THE
GFS NEXT WEEK WAS RIGHT...THE CORRESPONDING MOS TEMPERATURES STILL
LOOK WAY TOO HIGH. NOT ONLY HAS THE MEX MOS BEEN TOO WARM MUCH OF
THE SUMMER...BUT TODAY/S 12Z GFS RUN ALSO INDICATES CONSIDERABLE
CLOUDINESS AND PRECIPITATION NEXT TUESDAY AND WEDNESDAY...WHICH
WOULD HOLD DOWN MAXIMUM TEMPERATURES. USED THE STANDARD MODEL BLEND
FOR THE TEMPERATURE FORECAST WITH SOME MINOR TWEAKS...WHICH RESULTED
IN CONTINUED BELOW NORMAL TEMPERATURES...MAINLY DUE TO SUPPRESSED
DAYTIME HIGHS. WITH THE UNCERTAINTY ON EXACTLY WHERE THE QUASI
STATIONARY FRONT WILL SET UP NEXT WEEK...THE STANDARD BLEND PROVIDED
A REASONABLE SOLUTION FOR RAIN PROBABILITIES WITH AT LEAST A SLIGHT
OF SHOWERS AND THUNDERSTORMS IN THE FORECAST FROM MONDAY THROUGH
WEDNESDAY. THIS WILL ALSO BE IN GOOD AGREEMENT WITH NEIGHBORING
FORECAST OFFICES.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 220 AM EDT THU AUG 1 2013
FOG AND LOW CLOUDS WERE PREVALENT...BUT CONDITIONS VARIED WIDELY AT
THE START OF THE PERIOD...RANGING FROM VLIFR TO VFR. MOST PLACES CAN
EXPECT CONDITIONS DOWN TO AT LEAST IFR EVENTUALLY TONIGHT. ISOLATED
SHOWERS AND STORMS MAY AFFECT SOME LOCATIONS NEAR AND NW OF
INTERSTATE 64 AROUND DAWN. THE FOG IS EXPECTED TO LIFT INTO A LOW
CLOUD LAYER DURING THE MORNING. THESE CLOUDS WILL THEN LIFT AND BREAK
UP DURING THE DAY...WITH MOST PLACES BECOMING VFR BY EVENING.
HOWEVER...THE POSSIBILITY FOR ISOLATED SHOWERS AND THUNDERSTORMS WILL
CREEP SOUTHEAST ACROSS THE AREA DURING THE DAY...BEFORE FIZZLING OUT
LATE IN THE DAY. THE PROBABILITY OF PRECIP IS TOO LOW AT ANY GIVEN
POINT AT THIS TIME TO WARRANT INCLUSION IN THE TAFS.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...HAL
SHORT TERM...JJ
LONG TERM...SBH
AVIATION...HAL
AREA FORECAST DISCUSSION
NWS PADUCAH KY
1144 PM CDT Wed Jul 31 2013
.UPDATE...
ISSUED AT 1144 PM CDT WED JUL 31 2013
Updated aviation section for 06Z TAF package.
UPDATE ISSUED AT 849 PM CDT WED JUL 31 2013
A very weak surface convergence zone has developed along the
Wabash River this evening, and some isolated showers have
resulted. The most recent HRRR indicates that the convergence zone
and showers will slowly shift southeast through midnight. Decided
to add a slight chance/isolated pop over areas east of the Lakes
and Wabash through midnight.
All guidance shows a minor push of northwest winds and drier air
into the region overnight behind this convergence zone. Given some
variable cloud cover expected, the light northwest wind, and drier
air moving in, fog should not be a widespread problem overnight.
Made some adjustments to T/Td through the night to match these
overall trends and the current observations.
&&
.SHORT TERM...(This evening through Friday night)
Issued at 245 PM CDT Wed Jul 31 2013
Early this afternoon, a few showers and storms continue to flare
up near the KY/TN MO/AR borders in best instability axis per LAPS
surface data. Otherwise considerable clouds persist given ample
low level moisture, though minor improvement has been noted with
daytime heating and weak mixing. Not seeing much up north into
Missouri and Illinois. May leave pops out starting at 00z. We have
slight chances even north of the Ohio River through 00z just in
case there is a little development in an expanding zone of
instability. It may take the weak wave moving southeast across
MO/CNTRL IL to kick something off, if at all. Will monitor.
Otherwise tonight in the wake of the weak surface low, light NNW
winds below 5 kts are anticipated. Low level moisture will remain.
So there may be some fog. Not sure how much at this time,
especially if lower clouds remain a factor. May have to include
patchy fog in the forecast. Weak high pressure and overall drying
means dry Thursday through Thursday night. Then our attention
turns to the next impulse and a frontal boundary that will
approach Friday through Friday night. We have increasing pops from
north to south for convection. The overall model agreement is good
enough to use a compromise. Temperatures and humidity will be a
bit more summer like, but still tolerable as we head into early
August.
.LONG TERM...(Saturday Through Wednesday)
Issued at 245 PM CDT Wed Jul 31 2013
The northeast U.S. / southeast Canadian cold core vortex will
continue to dominate the medium range weather pattern from
Saturday through the middle of next week. The North American
Oscillation (NAO) ensembles indicate slightly negative values
through at least August 6th, suggesting that the vortex will
remain dominate in holding the base of the westerlies either over
the WFO PAH forecast area, or just to the southwest.
With this in mind, adjusted the probability of precipitation (PoP)
gradient further to the southwest over parts of southeast
Missouri, as well as southwest Illinois and Kentucky. Given the
thickness and moisture gradient, combined with subtle forcing from
passing upper level jetlets and low level insolation/differential
heating, kept the highest PoPs to the south and west of the
forecast area.
In all of the medium range forecast period, the time period of
mixed/lowest confidence is from after midnight Monday through the
daytime hours on Tuesday. The latest run (12z Wednesday) of the
operational ECMWF supports much lower PoPs compared to the 00z
run, indicating the lower PoPs may be the way to go over
Kentucky, Indiana, and most of southern Illinois. Unfortunately,
this scenario places our office with lower PoPs versus surrounding
NWS offices, with the possible exception of Nashville and Little
Rock NWS offices.
The negative NAO scenario will also keep maximum temperature 3 to 7
degrees below normal highs for this time of year.
&&
.AVIATION...
ISSUED AT 1144 PM CDT WED JUL 31 2013
Brief VFR cigs possible through 09z, otherwise skc-sct040
overnight. VFR to MVFR vsbys expected through 13z. Expect sct-
bkn040 cu between 14z and 00z along with vfr vsbys. Light and
variable/calm winds overnight will be northwest/north at 5-10kts
after 14z, then go calm after 01z.
&&
.PAH WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
MO...NONE.
IN...NONE.
KY...NONE.
&&
$$
SHORT TERM...Noles
LONG TERM... Smith
AVIATION...RST
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
1230 AM EDT THU AUG 01 2013
.FORECAST UPDATE...
Issued at 1230 AM EDT Thu Aug 01 2013
A quick update to add some patchy fog into the forecast early this
morning. A couple of obs sites have dropped below 2 miles, and with
mostly clear skies hanging on for a little while longer expect that
patchy fog could linger into the pre-dawn hours. Still do expect
stratus to gradually build in, which should end the patchy fog
threat toward dawn. Otherwise, forecast is still on track with
isolated showers along a weak surface trough slowly sinking SE into
southern Indiana over the next few hours.
Previous Update...
Issued at 1000 PM EDT Wed Jul 31 2013
Did an update to align near-term forecast with trends in obs. The
first frontal boundary is pushing southeast out of our forecast area
and taking with it the broken line of showers across the Lake
Cumberland region. Behind that line, there are areas of drizzle
associated with the low stratus that hung around for much of the
day. This drizzle should drift southeast and diminish within the
next few hours. The stratus is breaking up, with mostly clear skies
across our west and northwest counties. Have updated the forecast to
cover all these trends in the near-term.
Another feature of note is a surface trough stretching southwest
through central IN into southern IL. There are a few isolated
showers along this boundary and it is edging our way. Some hi-res
models bring those into our northern CWA. Have added isolated
showers across our north through about 2 AM EDT.
All of the latest guidance indicates low stratus will build across
the region, mainly after midnight. So, even though some areas are
experiencing mostly clear skies, believe that will change as the
night progresses. Have bumped up the cloud cover from around
midnight through sunrise, with clouds beginning to dissipate mid to
late morning. Cannot rule out some patchy fog/mist/haze with this
stratus that will build in overnight, reducing visibilities just a
bit. All updates will be out shortly.
&&
.SHORT TERM (Tonight through Thursday night)...
Issued at 310 PM EDT Tue Jul 31 2013
Weak surface trof sits just this side of US 41, with light NNE winds
in southern Illinois and western Kentucky, while we are still
southerly here in central Kentucky and southern Indiana. Extensive
low cloud deck maintains its hold on the Ohio Valley as soundings
are pretty well saturated up to about 700mb. A few showers have
tried to pop in south central Kentucky, but any instability to
support thunder is suppressed well down into Tennessee.
Still can`t rule out a shower through early evening, as is evident
by that weak activity in the south. More likely scenario is probably
sprinkles, but the main theme of the night will be low clouds. Could
also be some light fog, but because of the stratus we do not expect
visibilities to drop enough to have any impacts other than aviation.
Otherwise expect a muggy night with temps near or just a couple
degrees below normal.
Deep NW flow on Thursday will finally dry out the column, so morning
stratus will give way to a partly sunny afternoon. Temps will run
below normal, as 850mb temps at 14C will only allow for lower 80s,
even in fairly deep mixing. Decent radiational cooling conditions
Thursday night will provide more free air conditioning, with temps
dipping into the lower 60s in most locations, with even a few 50s
possible in the traditionally cooler spots.
.LONG TERM (Friday through Wednesday)...
Issued at 232 PM EDT Wed Jul 31 2013
Surface high pressure to start off this forecast period will begin
to lose its hold over the Ohio Valley by early Saturday as a frontal
boundary sags southward across Indiana. Latest GFS run (12Z) shows
the front clearing south of the forecast area by Sunday, allowing
for the next surface high to move on through. Once again, however,
the two major long-term deterministic models disagree and diverge by
Monday on the pattern. The GFS has the high shunting off of the East
Coast by Monday evening, allowing for some possible convection to
fire up, especially in southern Kentucky where GFS PW values run
close to 2 inches. The focus for precip relies on a series of
shortwaves rotating through early next week. The 00Z ECMWF,
meanwhile, has the high washing out somewhere over the East Coast,
leaving the region in a messy pattern with two weak surface lows to
our NE and SE. By Wednesday, the models are drastically different
with the GFS trying to bring a cold front associated with a surface
low through the region while the ECMWF has us dry and already under
northerly flow. The two models are spatially displaced on a Canadian
upper low that should ultimately be the determining factor in our
local weather for Monday through Wednesday. Therefore, once again,
confidence in the forecast for the latter half of this period
remains low at best. Given that yesterday`s 12Z ECMWF came in at a
bit of a closer agreement to the 12Z GFS for the same forecast time
frame, am leaning more toward the GFS in tweaking today`s forecast
for the upcoming work week.
To summarize the precip forecast, showers and thunderstorms should
begin to approach southern Indiana by Friday afternoon, eventually
overspreading the area by Saturday. Instability looks decent enough
to warrant good thunderstorm potential with the slight chance of
some storms becoming strong, but only if a break in the cloud cover
allows for decent daytime heating. Any stronger storm would contain
gusty winds. By the end of the weekend, any remaining activity
should be contained primarily in southern KY and clear of the
forecast area by Sunday night. Again, confidence beyond this point
is low, but should it pan out, we`ll see this brief lull in precip
chances overnight Sunday before at least a slight chance of
thunderstorms creeps back in on Monday. Currently, have depicted the
"best" (relatively speaking) precip chances Tuesday, waning after
sunset and potentially re-emerging on Wednesday.
Temperatures continue to look like they`ll remain near or slightly
below normal for this time of year, with the warmest two days during
this period occurring on Friday and Wednesday. Cloud cover and
precip will, of course, throw a wrench into the mix for temperature
forecasts. Highs on Friday will be in the mid 80s with lows in the
upper 60s. Have bumped up Saturday highs slightly, giving the area
low to mid 80s as highs. From Sunday onward, look for fluctuating
highs ranging from the low to mid (and possibly upper) 80s and lows
in the 60s to near 70.
&&
.AVIATION (00Z TAF Update)...
Issued at 725 PM EDT Wed Jul 31 2013
Rain potential is slim to none at all sites, so the main concern
will be cigs and vis overnight. Back edge of low stratus is
approaching SDF from the northwest and should arrive shortly before
02Z, with VFR conditions to follow for a few hours. This will take a
little longer to reach LEX if it can make it there. BWG broke out
earlier this afternoon, but there remains a chance to drop back to
MVFR until that back edge finally moves through, around 02-03Z. This
VFR window is in response to slight ridging ahead of our next
shortwave, which is slated to move across the Ohio Valley overnight.
The second band of low stratus across central IL is associated with
the shortwave for tonight. Latest guidance either builds lower
stratus or advects it in from the west around 05-06Z. The RAP and
WRF simulated GOES-R show the low stratus developing a little later,
closer to 07-09Z, particularly for BWG and SDF. So, confidence in
timing remains low, but it certainly appears fuel-alternate cigs are
a sure bet for all sites, with some bases approaching alternate
minimums at BWG and LEX. Expect vis to drop generally into the MVFR
range with the low stratus. Conditions should begin to improve
around or shortly after 15Z, with VFR conditions expected by the
afternoon hours. Winds will remain light and variable overnight and
pick up out of the northwest around mid morning Thursday, with
speeds in the 6-9 knot range expected through the afternoon.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
KY...NONE.
$$
Update...........MJP/BJS
Short Term.......RAS
Long Term........LG
Aviation.........MJP
AREA FORECAST DISCUSSION
NWS NEW ORLEANS LA
330 PM CDT THU AUG 1 2013
.SHORT TERM...
A SOMEWHAT ACTIVE AFTERNOON FOR PORTIONS OF THE FORECAST AREA
BRINGS HIGHER RAIN CHANCES. A COLD FRONT HAS BEEN SLOWLY TRACKING
RIGHT ACROSS MID MISSISSIPPI AND SHOULD BE APPROACHING LATER THIS
AFTERNOON. CONVECTION HAS BEGUN TO FIRE OFF AHEAD OF THE BOUNDARY
NORTH OF THE CWA. LOCAL WRF ALONG WITH HRRR IN FAIRLY GOOD AGREEMENT
DENOTING THAT CURRENT ACTIVITY WHICH IS TYPICAL OF THIS TIME OF
YEAR WILL INCREASE IN COVERAGE AS WELL AS INTENSITY AND MOVE ACROSS
THE CWA. PRECIP WATER VALUES ARE STILL QUITE HIGH AT OVER 2
INCHES...SO EXPECT VERY HEAVY RAIN WITH ANY STORMS THAT DO DEVELOP.
WIND SHEAR IS QUITE LIGHT AND WEST BULB TEMP WELL ABOVE 13K FEET
MEANS LITTLE THREAT OF HAIL OR TORNADOES. THUS THE MAIN THREAT WILL
BE GUSTY WINDS ON THE ORDER OF 35-45 MPH. SEVERE GUSTS NOT
IMPOSSIBLE BUT UNLIKELY. CONVECTION WILL LIKELY PERSIST THROUGH
SUNSET BUT NOT MUCH LONGER AFTER THAT. MAIN THREAT AREA APPEARS TO
BE EAST OF INTERSTATE 55 FROM MS ALL THE WAY TO SOUTH OF NEW
ORLEANS. HAVE BUMPED UP POPS SLIGHTLY FROM PREVIOUS FORECAST.
MEFFER
&&
.LONG TERM...
UPPER LEVEL TROUGH WILL LIFT NORTH AND RIDGE WILL BEGIN EXTENDING IN
OVER THE AREA FRIDAY THROUGH THE WEEKEND. WHILE A FEW STORMS MAY
DEVELOP...CONVECTION SHOULD BE QUITE LIMITED. EASTERN EDGE OF THE
UPPER LEVEL RIDGE WILL BEGIN WEAKENING LATE THIS WEEKEND THROUGH THE
MIDDLE OF NEXT WEEK. THIS WILL ALLOW FOR A FEW RAIN CHANCES TO
INCREASE ACROSS THE AREA. TEMPERATURES THROUGH THE ENTIRE PERIOD
WILL NOT CHANCE MUCH WITH HIGHS GENERALLY IN THE 90-95 DEGREE RANGE
WITH HEAT INDEX VALUES 100 TO 105. MID WEEK ONWARD THE RIDGE WILL
MOVE DIRECTLY OVER THE NORTHERN GULF COAST. ECMWF SUGGESTS A
SLIGHTLY STRONGER RIDGE WITH LOWER POPS AND HIGHER TEMPS WHILE GFS
IS MORE OF A WEAKER RIDGE WHICH WOULD ALLOW FOR MORE CONVECTION. SO
HAVE MADE LITTLE TO NO CHANGES TO THE EXTENDED FORECAST.
MEFFER
&&
AVIATION...
GENERALLY VFR CONDITIONS ARE EXPECTED TO PREVAIL THROUGH 00Z
SATURDAY AT THE TERMINAL LOCATIONS. THE POSSIBLE EXCEPTIONS WILL BE
ASSOCIATED WITH THE POTENTIAL FOR LIGHT FOG DEVELOPMENT TOWARD
DAYBREAK FRIDAY MORNING AT THE MORE FOG PRONE TAF SITES. THE
TERMINALS IN THE SOUTH HALF OF THE FORECAST AREA ARE THE ONES THAT
WILL HAVE THE BEST CHANCE OF SEEING ANY CONVECTION...NAMELY
KHUM...KNEW AND KMSY...BUT RAIN CHANCES WILL REMAIN SLIM.
18
&&
MARINE...
A RIDGE OF HIGH PRESSURE WILL FLUCTUATE BETWEEN THE EASTERN AND
CENTRAL GULF THROUGHOUT THE FORECAST PERIOD. GENERALLY LIGHT SOUTH
TO WESTERLY AND AT TIMES VARIABLE WINDS AROUND 10 KNOTS OR LESS ARE
EXPECTED ALONG WITH WAVES HEIGHTS OF 2 FEET OR LESS.
MEFFER
&&
DECISION SUPPORT...
DSS CODE...BLUE.
DEPLOYED...NONE.
ACTIVATION...NONE.
ACTIVITIES...NATURAL GAS WELL BLOWOUT SUPPORT.
SLURRY SUPPORT.
DECISION SUPPORT SERVICES (DSS) CODE LEGEND
GREEN = NO WEATHER IMPACTS THAT REQUIRE ACTION
BLUE = LONG FUSED WATCH/WARNING/ADVISORY IN EFFECT OR HIGH
VISIBILITY EVENT
YELLOW = HEIGHTENED IMPACTS WITH SHORT FUSED
WATCH/WARNING/ADVISORY ISSUANCES; RADAR SUPPORT
ORANGE = HIGH IMPACTS - SLIGHT TO MODERATE RISK SEVERE; NEARBY
TROPICAL EVENTS; HAZMAT OR OTHER LARGE EPISODES
RED = FULL ENGAGEMENT FOR MODERATE TO HIGH RISK SVR
AND/OR DIRECT TROPICAL THREATS; EVENTS OF NATIONAL
SIGNIFICANCE
&&
.PRELIMINARY POINT TEMPS/POPS...
MCB 74 95 73 94 / 10 10 10 10
BTR 77 96 76 95 / 10 10 10 10
ASD 76 94 76 93 / 20 20 10 20
MSY 79 93 78 92 / 20 20 10 20
GPT 77 93 77 93 / 20 20 10 20
PQL 73 94 73 93 / 20 20 10 20
&&
.LIX WATCHES/WARNINGS/ADVISORIES...
LA...NONE.
GM...NONE.
MS...NONE.
GM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
524 PM EDT THU AUG 1 2013
.SYNOPSIS...
A COLD FRONT WILL MOVE OFF THE COAST AND INTO THE CAROLINAS
OVERNIGHT. HIGH PRESSURE RETURNS ON FRIDAY AND SATURDAY. ANOTHER
COLD FRONT CROSSES THE REGION ON SUNDAY WITH HIGH PRESSURE BUILDING
BACK INTO THE AREA EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
THURSDAY AFTN...A COLD FRONT WAS SITUATED OVER WEST VIRGINIA AND WAS
MOVING TO THE SOUTHEAST. VARIOUS SURFACE TROUGHS FURTHER TO THE EAST
WERE RESULTING IN AREAS OF CONVERGENCE WITH SOME DOWNSLOPING AND
DRYING MOVING INTO THE CWA. THE MAIN CONVERGENCE WAS ALONG A BAND
NEAR THE CHESAPEAKE. ANOTHER WAS APPROACHING OUR NORTHWEST COUNTIES
FROM THE BLUE RIDGE. HAVE DROPPED POPS GENERALLY WEST OF INTERSTATE
95 FOR THE REST OF THE AFTN. NORTHWEST COUNTIES MAY EXPERIENCE A
BRIEF TSTM BUT OVERALL CONDITIONS SHOULD BE DRY OVER WRN PORTIONS.
A SHORT WAVE TROUGH AND RRQ OF UPPER LEVEL JET WILL MAINTAIN THE
POSSIBILITY OF TSTMS NEAR COASTAL AREAS WELL INTO THE EVENING HOURS.
THE THREAT FOR LOCALLY HEAVY RAINFALL WILL CONTINUE OVER THE EASTERN
SHORE AND HAMPTON ROADS AND NEAR THE CHESAPEAKE THROUGH THE EARLY
EVENING HOURS.
DEW POINTS SLOWLY DROP AND MIN TEMPERATURES WILL BE A BIT COOLER
THAN THURSDAY MORNING OVER INLAND AREAS. LOWS SHOULD DROP IN THE MID
TO UPR 60S INLAND TO AROUND 70 NEAR THE COAST FRIDAY MORNING.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH SUNDAY/...
DRY WEATHER WILL PREVAIL FRIDAY AS WEAK HIGH PRESSURE BUILDS INTO
THE REGION BEHIND THE AFOREMENTIONED SHORT WAVE TROUGH. PLENTY OF
SUNSHINE SHOULD ALLOW TEMPERATURE TO APPROACH 90 DEGREES OVER INLAND
AREAS AND THE MID 80S NEAR THE COAST. MOSTLY CLEAR SKIES CONTINUE
FRIDAY NIGHT WITH LOWS IN THE MID 60S WELL INLAND TO THE LWR 70S IN
THE HAMPTON ROADS AREA.
MID LEVEL MOISTURE INCREASES AHEAD OF THE NEXT COLD FRONT SATURDAY.
HAVE A CHC FOR SHOWERS AND THUNDERSTORMS BY THE AFTN...MAINLY OVER
NORTHERN AND EASTERN PORTIONS. HIGH TEMPERATURES WILL BE IN THE UPR
80S TO AROUND 90.
THE COLD FRONT MOVES IN FROM THE N/NW SUNDAY. MAINLY USED NAM/SREF
FOR THE TIMING OF THE FRONT...THE GFS LOOKS TOO FAST AND AGGRESSIVE.
HAVE A CHC FOR TSTMS WITH THE FRONTAL PASSAGE...ENDING FROM N TO S
THROUGH THE AFTN. CLOUD COVER SHOULD HOLD TEMPERATURES DOWN TO THE
MID TO UPR 80S SUNDAY.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
MEDIUM RANGE LOOKS TO BE CHARACTERIZED BY AN UPPER LEVEL RIDGE
OVER THE INTERMOUNTAIN WEST INTO WESTERN CANADA, WHILE AN UPPER
LEVEL TROUGH PERSISTS OVER THE NORTHEASTERN CONUS. THIS WILL PROMOTE
RELATIVELY COOLER AND DRIER AIR TO DRAIN OUT OF THE CANADIAN
PRAIRIES ACROSS THE NORTHEASTERN AND MID-ATLANTIC REGIONS.
FORECAST PERIOD BEINGS SUNDAY NIGHT WITH A WEAKENING BACKDOOR FRONT
DROPPING ACROSS THE AREA, LIKELY BECOMING STALLED ACROSS THE
CAROLINAS BEFORE WASHING OUT EARLY NEXT WEEK. IN ITS WAKE, EXPECT A
MAINLY DRY FORECAST, THOUGH WE DID RETAIN A SLIGHT CHC POP MAINLY
SOUTH OF HIGHWAY 58 CORRIDOR IN S VA/NE NC. SFC HIGH SLIDES OFFSHORE
TUESDAY/WEDNESDAY, WITH S-SW FLOW RETURNING AND BUMPING TEMPS UP
CLOSER TO SEASONAL VALUES FOR MIDWEEK. AS FOR SENSIBLE WX, WILL ALSO
SEE INCREASING (MAINLY DIURNALLY DRIVEN) SHRA/TSTM CHCS BOTH DAYS AS
SHORTWAVE ENERGY EMBEDDED IN THE LONGWAVE TROUGH MOVES ACROSS THE
NORTHERN MID-ATLANTIC. FOR TEMPERATURES, EXPECT MAXIMA TO AVERAGE
BELOW NORMAL FOR THE PERIOD, GENERALLY BE IN THE LOW TO MID
80S...AGAIN EXPECTING TEMPS TO RISE BACK UP TOWARDS NORMAL AHEAD OF
ANOTHER SLOW MOVING FRONT BY LATE NEXT WEEK. EARLY MORNING LOWS TO
AVERAGE IN THE LOWER TO MIDDLE 60S.
&&
.AVIATION /22Z THURSDAY THROUGH TUESDAY/...
WITH COLD FRONT MOVING THROUGH THIS AFTERNOON AND SHOWERS AND SOME
THUNDERSTORMS DEVELOPING ACROSS THE AREA. SEVERAL SHORT LINES HAVE
FORMED. TRIED TO TIME THEM THROUGH THE TERMINALS. ALSO FOLLOWING
RUC TIMING AS WELL AS THAT SEEMS TO HAVE A GOOD HANDLE ON THE
CURRENT CONVECTION. HRRR TRIES TO BRING CONVECTION OVER NORTHWEST
VIRGINIA INTO CENTRAL AND SOUTHEAST VIRGINIA TOWARD MIDNIGHT. NOT
SURE IF THIS WILL HOLD TOGETHER SO DID NOT INCLUDE IN THE TAFS.
WILL HAVE WATCH FOR LATER CHANGES. COULD SEE SOME FOG DEVELOP
AFTER THESE SHOWERS AS THE COLD FRONT DOES NOT CROSS THE AREA
UNTIL THE EARLY MORNING HOURS. AFTER SUNRISE ON FRIDAY CONDITIONS
WILL BECOME VFR AND REMAIN SO THROUGH MUCH OF SATURDAY. NEXT
SYSTEM APPROACHES SATURDAY AND SUNDAY WITH MORE THUNDERSTORMS
DEVELOPING AND COULD SEE SOME MVFR TO IFR CONDITIONS IN THE
THUNDERSTORMS.
&&
.MARINE...
LATEST OBS REFLECT S-SW WINDS ~15 KT. PRESSURE GRADIENT CONTINUES TO
TIGHTEN OVER THE WATERS AHEAD OF WK LO PRES, WHICH WILL PASS BY JUST
TO OUR NORTH THROUGH TODAY. ASSOCIATED CDFNT WILL PUSH ACROSS THE
WATERS TONIGHT. NOTING WINDS AT LOW END SCA IN THE BAY THIS AFTN,
AND SCA REMAINS IN PLACE OVER THE CHES BAY THROUGH 23Z/7PM FOR
FREQUENT WIND GUSTS ~20KT. CONSIDERED ADDING SCA FOR THE CURRITUCK
SOUND, BUT WL CAP OFF WINDS AT 15 KT THROUGH 7PM WITH THE IDEA THAT
BRIEF WINDOW OF HIGHER WINDS WILL BE MORE CONVECTIVE THAN ANYTHING
ELSE...AND THUS BEST HANDLED WITH SMW AS NEEDED.
WINDS WILL DIMINISH AFTER 00Z/8P AS GRADIENT SLACKENS WITH THE
APPROACH OF THE WEAKENING FRONT. WINDS VEER TO SW OVERNIGHT,
EVENTUALLY BECOMING WNW ERY FRIDAY. FRONT CONTINUES TO WEAKEN JUST
TO OUR SOUTH/SOUTHEAST TOMORROW, AS SFC HI PRES REBUILDS WEST OF THE
WATERS FRI INTO ERY SAT. SUB-SCA CONDS ARE EXPECTED DURING THIS
PERIOD, WITH WAVES/SEAS AVERAGING 2-4FT. NEXT CDFNT (BACKDOOR FRONT)
DROPS SOUTH ACROSS THE WATERS LATER SUN. POTENTIAL EXISTS FOR
ANOTHER BRIEF SURGE AHEAD OF THIS FRONT DURING THE DAY SUNDAY. WINDS
VEER AROUND TO THE E-SE MONDAY AS SFC HIGH PIVOTS OFF THE
MID-ATLANTIC COAST LATER MONDAY AND TUESDAY. LIGHT SOUTHERLY FLOW
FOLLOWS FOR LATER TUE/WED...AHEAD OF NEXT FRONT WHICH FOLLOWS BY
LATE NEXT WEEK.
&&
.EQUIPMENT...
THE NOAA RADIO TRANSMITTER OUT OF RICHMOND HAS RETURNED TO
SERVICE.
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 7 PM EDT THIS EVENING FOR
ANZ630>632-634.
&&
$$
SYNOPSIS...LSA
NEAR TERM...LSA
SHORT TERM...LSA
LONG TERM...MAM
AVIATION...JAB
MARINE...MAM
EQUIPMENT...
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
359 PM EDT THU AUG 1 2013
.SYNOPSIS...
A COLD FRONT WILL MOVE OFF THE COAST AND INTO THE CAROLINAS
OVERNIGHT. HIGH PRESSURE RETURNS ON FRIDAY AND SATURDAY. ANOTHER
COLD FRONT CROSSES THE REGION ON SUNDAY WITH HIGH PRESSURE BUILDING
BACK INTO THE AREA EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
THURSDAY AFTN...A COLD FRONT WAS SITUATED OVER WEST VIRGINIA AND WAS
MOVING TO THE SOUTHEAST. VARIOUS SURFACE TROUGHS FURTHER TO THE EAST
WERE RESULTING IN AREAS OF CONVERGENCE WITH SOME DOWNSLOPING AND
DRYING MOVING INTO THE CWA. THE MAIN CONVERGENCE WAS ALONG A BAND
NEAR THE CHESAPEAKE. ANOTHER WAS APPROACHING OUR NORTHWEST COUNTIES
FROM THE BLUE RIDGE. HAVE DROPPED POPS GENERALLY WEST OF INTERSTATE
95 FOR THE REST OF THE AFTN. NORTHWEST COUNTIES MAY EXPERIENCE A
BRIEF TSTM BUT OVERALL CONDITIONS SHOULD BE DRY OVER WRN PORTIONS.
A SHORT WAVE TROUGH AND RRQ OF UPPER LEVEL JET WILL MAINTAIN THE
POSSIBILITY OF TSTMS NEAR COASTAL AREAS WELL INTO THE EVENING HOURS.
THE THREAT FOR LOCALLY HEAVY RAINFALL WILL CONTINUE OVER THE EASTERN
SHORE AND HAMPTON ROADS AND NEAR THE CHESAPEAKE THROUGH THE EARLY
EVENING HOURS.
DEW POINTS SLOWLY DROP AND MIN TEMPERATURES WILL BE A BIT COOLER
THAN THURSDAY MORNING OVER INLAND AREAS. LOWS SHOULD DROP IN THE MID
TO UPR 60S INLAND TO AROUND 70 NEAR THE COAST FRIDAY MORNING.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH SUNDAY/...
DRY WEATHER WILL PREVAIL FRIDAY AS WEAK HIGH PRESSURE BUILDS INTO
THE REGION BEHIND THE AFOREMENTIONED SHORT WAVE TROUGH. PLENTY OF
SUNSHINE SHOULD ALLOW TEMPERATURE TO APPROACH 90 DEGREES OVER INLAND
AREAS AND THE MID 80S NEAR THE COAST. MOSTLY CLEAR SKIES CONTINUE
FRIDAY NIGHT WITH LOWS IN THE MID 60S WELL INLAND TO THE LWR 70S IN
THE HAMPTON ROADS AREA.
MID LEVEL MOISTURE INCREASES AHEAD OF THE NEXT COLD FRONT SATURDAY.
HAVE A CHC FOR SHOWERS AND THUNDERSTORMS BY THE AFTN...MAINLY OVER
NORTHERN AND EASTERN PORTIONS. HIGH TEMPERATURES WILL BE IN THE UPR
80S TO AROUND 90.
THE COLD FRONT MOVES IN FROM THE N/NW SUNDAY. MAINLY USED NAM/SREF
FOR THE TIMING OF THE FRONT...THE GFS LOOKS TOO FAST AND AGGRESSIVE.
HAVE A CHC FOR TSTMS WITH THE FRONTAL PASSAGE...ENDING FROM N TO S
THROUGH THE AFTN. CLOUD COVER SHOULD HOLD TEMPERATURES DOWN TO THE
MID TO UPR 80S SUNDAY.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
MEDIUM RANGE LOOKS TO BE CHARACTERIZED BY AN UPPER LEVEL RIDGE
OVER THE INTERMOUNTAIN WEST INTO WESTERN CANADA, WHILE AN UPPER
LEVEL TROUGH PERSISTS OVER THE NORTHEASTERN CONUS. THIS WILL PROMOTE
RELATIVELY COOLER AND DRIER AIR TO DRAIN OUT OF THE CANADIAN
PRAIRIES ACROSS THE NORTHEASTERN AND MID-ATLANTIC REGIONS.
FORECAST PERIOD BEINGS SUNDAY NIGHT WITH A WEAKENING BACKDOOR FRONT
DROPPING ACROSS THE AREA, LIKELY BECOMING STALLED ACROSS THE
CAROLINAS BEFORE WASHING OUT EARLY NEXT WEEK. IN ITS WAKE, EXPECT A
MAINLY DRY FORECAST, THOUGH WE DID RETAIN A SLIGHT CHC POP MAINLY
SOUTH OF HIGHWAY 58 CORRIDOR IN S VA/NE NC. SFC HIGH SLIDES OFFSHORE
TUESDAY/WEDNESDAY, WITH S-SW FLOW RETURNING AND BUMPING TEMPS UP
CLOSER TO SEASONAL VALUES FOR MIDWEEK. AS FOR SENSIBLE WX, WILL ALSO
SEE INCREASING (MAINLY DIURNALLY DRIVEN) SHRA/TSTM CHCS BOTH DAYS AS
SHORTWAVE ENERGY EMBEDDED IN THE LONGWAVE TROUGH MOVES ACROSS THE
NORTHERN MID-ATLANTIC. FOR TEMPERATURES, EXPECT MAXIMA TO AVERAGE
BELOW NORMAL FOR THE PERIOD, GENERALLY BE IN THE LOW TO MID
80S...AGAIN EXPECTING TEMPS TO RISE BACK UP TOWARDS NORMAL AHEAD OF
ANOTHER SLOW MOVING FRONT BY LATE NEXT WEEK. EARLY MORNING LOWS TO
AVERAGE IN THE LOWER TO MIDDLE 60S.
&&
.AVIATION /20Z THURSDAY THROUGH TUESDAY/...
WITH COLD FRONT MOVING THROUGH THIS AFTERNOON AND SHOWERS AND SOME
THUNDERSTORMS DEVELOPING ACROSS THE AREA. SEVERAL SHORT LINES HAVE
FORMED. TRIED TO TIME THEM THROUGH THE TERMINALS. ALSO FOLLOWING
RUC TIMING AS WELL AS THAT SEEMS TO HAVE A GOOD HANDLE ON THE
CURRENT CONVECTION. HRRR TRIES TO BRING CONVECTION OVER NORTHWEST
VIRGINIA INTO CENTRAL AND SOUTHEAST VIRGINIA TOWARD MIDNIGHT. NOT
SURE IF THIS WILL HOLD TOGETHER SO DID NOT INCLUDE IN THE TAFS.
WILL HAVE WATCH FOR LATER CHANGES. COULD SEE SOME FOG DEVELOP
AFTER THESE SHOWERS AS THE COLD FRONT DOES NOT CROSS THE AREA
UNTIL THE EARLY MORNING HOURS. AFTER SUNRISE ON FRIDAY CONDITIONS
WILL BECOME VFR AND REMAIN SO THROUGH MUCH OF SATURDAY. NEXT
SYSTEM APPROACHES SATURDAY AND SUNDAY WITH MORE THUNDERSTORMS
DEVELOPING AND COULD SEE SOME MVFR TO IFR CONDITIONS IN THE
THUNDERSTORMS.
&&
.MARINE...
LATEST OBS REFLECT S-SW WINDS ~15 KT. PRESSURE GRADIENT CONTINUES TO
TIGHTEN OVER THE WATERS AHEAD OF WK LO PRES, WHICH WILL PASS BY JUST
TO OUR NORTH THROUGH TODAY. ASSOCIATED CDFNT WILL PUSH ACROSS THE
WATERS TONIGHT. NOTING WINDS AT LOW END SCA IN THE BAY THIS AFTN,
AND SCA REMAINS IN PLACE OVER THE CHES BAY THROUGH 23Z/7PM FOR
FREQUENT WIND GUSTS ~20KT. CONSIDERED ADDING SCA FOR THE CURRITUCK
SOUND, BUT WL CAP OFF WINDS AT 15 KT THROUGH 7PM WITH THE IDEA THAT
BRIEF WINDOW OF HIGHER WINDS WILL BE MORE CONVECTIVE THAN ANYTHING
ELSE...AND THUS BEST HANDLED WITH SMW AS NEEDED.
WINDS WILL DIMINISH AFTER 00Z/8P AS GRADIENT SLACKENS WITH THE
APPROACH OF THE WEAKENING FRONT. WINDS VEER TO SW OVERNIGHT,
EVENTUALLY BECOMING WNW ERY FRIDAY. FRONT CONTINUES TO WEAKEN JUST
TO OUR SOUTH/SOUTHEAST TOMORROW, AS SFC HI PRES REBUILDS WEST OF THE
WATERS FRI INTO ERY SAT. SUB-SCA CONDS ARE EXPECTED DURING THIS
PERIOD, WITH WAVES/SEAS AVERAGING 2-4FT. NEXT CDFNT (BACKDOOR FRONT)
DROPS SOUTH ACROSS THE WATERS LATER SUN. POTENTIAL EXISTS FOR
ANOTHER BRIEF SURGE AHEAD OF THIS FRONT DURING THE DAY SUNDAY. WINDS
VEER AROUND TO THE E-SE MONDAY AS SFC HIGH PIVOTS OFF THE
MID-ATLANTIC COAST LATER MONDAY AND TUESDAY. LIGHT SOUTHERLY FLOW
FOLLOWS FOR LATER TUE/WED...AHEAD OF NEXT FRONT WHICH FOLLOWS BY
LATE NEXT WEEK.
&&
.EQUIPMENT...
THE NOAA RADIO TRANSMITTER OUT OF RICHMOND IS OFF THE AIR.
TECHNICIANS ARE WORKING THE ISSUE. THERE IS NO ESTIMATE FOR SERVICE
RESTORATION AT THIS TIME.
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 7 PM EDT THIS EVENING FOR
ANZ630>632-634.
&&
$$
SYNOPSIS...LSA
NEAR TERM...LSA
SHORT TERM...LSA
LONG TERM...MAM
AVIATION...JAB
MARINE...MAM
EQUIPMENT...
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
237 PM EDT THU AUG 1 2013
.SYNOPSIS...
A MOIST AIR MASS WILL REMAIN IN PLACE TODAY AS A COLD FRONT
APPROACHES FROM THE WEST. THE COLD FRONT WILL MOVE OFF THE COAST
TONIGHT. HIGH PRESSURE RETURNS ON FRIDAY. ANOTHER COLD FRONT
CROSSES THE REGION SATURDAY NIGHT INTO SUNDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
EARLY AFTN UPDATE...
STLT AND RADAR TRENDS INDICATE THAT DOWNSLOPING AND DRYING HAVE
ENDED SIGNIFICANT PCPN OVER THE PIEDMONT AREA. POPS HAVE BEEN
LOWERED WEST OF INTERSTATE 95 FOR THE REST OF THE AFTN IN THAT
AREA.
PREVIOUS DISCUSSION...
A WARM FRONT LIFTED TO THE NORTH OF THE CWA THIS MORNING. A MOIST
AIR MASS WILL REMAIN IN PLACE TODAY WITH PRECIPITABLE WATER CLOSE
TO 2 INCHES. A LEE SIDE TROUGH NEAR THE BLUE RIDGE SEPARATES S/SW
WINDS AND DEW POINTS AROUND 70 TO LOWER 70S FROM DEW POINTS IN THE
LOW TO MID 60S TO THE WEST. THE MAIN COLD FRONT IS SITUATED OVER
THE OHIO VALLEY.
SHOWERS CONTINUE THURSDAY MORNING ACROSS THE AREA WITH THE BIGGEST
CONCENTRATION NEAR THE COAST AND IN AREAS OF NORTH OF RICHMOND. AN
80H TROUGH WHICH WAS NEAR THE OH VALLEY SURFACE FRONT EARLY THIS
MORNING WILL SWEEP ACROSS THE REGION THIS AFTN AND EVENING. IT WILL
HELP TO PRODUCE WIDESPREAD SHOWER ACTIVITY WITH SOME EMBEDDED
THUNDERSTORMS. CONVECTIVE TEMPERATURES WILL RANGE FROM THE UPR 70S
TO MID 80S DURING THE AFTN. CLOUD COVER WILL PUT A DAMPER ON TSTM
ACTIVITY BUT AREAS OF HEAVY RAINFALL CAN BE EXPECTED. THE POTENTIAL
FOR MINOR FLOODING WILL BE GREATEST IN THOSE LOCATIONS WHICH
RECEIVED COPIOUS RAINFALL DURING THE PAST 24 HOURS...MAINLY OVER
PORTIONS OF NOTTOWAY AND DINWIDDIE COUNTIES TO NEAR PETERSBURG WHICH
RECEIVED ITS RAINFALL LATE WEDNESDAY AFTN. ALSO 2 TO 3 INCHES OF
RAIN FELL IN NORTHEAST NORTH CAROLINA IN A NARROW BAND FROM THE
PERQUIMANS COUNTY NEAR THE ALBEMARLE SOUND TO PORTIONS OF CURRITUCK
COUNTY.
DUE TO CLOUD COVER AND AN EVALUATION OF MODEL GUIDANCE...HIGH
TEMPERATURES WERE LOWERED A BIT FOR TODAY WITH FORECAST MAXIMUMS IN
THE LOWER 80S IN MOST LOCATIONS.
PRECIPITATION DIMINISHES FROM W TO E THIS EVENING AS THE 80H TROUGH
MOVES OFFSHORE. MODELS ESPECIALLY THE NAM SUGGEST THAT THE SURFACE
FRONTAL PASSAGE WILL BE WEAK BUT A SUBTLE LOWERING OF THE DEW POINT
CAN BE EXPECTED TOWARD MORNING. LOWS TONIGHT ARE FORECAST IN THE MID
60S TO LWR 70S.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY/...
LOOKS LIKE DRY WX WILL PREVAIL FRIDAY AS THE SFC COLD FRONT MAKES
ENOUGH PROGRESS SOUTH AND HIGH PRESSURE IS ABLE TO RETURN. PARTLY
TO MOSTLY SUNNY AND WARMER WITH HIGHS IN THE MID 80S TO AROUND 90.
LOWS FRIDAY NIGHT IN THE MID 60S TO LOW 70. AN APPROACHING MID-LEVEL
TROF AND INCREASING MOISTURE WILL LEAD TO A CHC FOR SHOWERS BY SAT
AFTN (ESPECIALLY N-NW). HIGHS IN THE 80S TO LOW 90S.
&&
.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
MEDIUM RANGE LOOKS TO BE CHARACTERIZED BY AN UPPER LEVEL RIDGE
OVER THE INTERMOUNTAIN WEST INTO WESTERN CANADA, WHILE AN UPPER
LEVEL TROUGH PERSISTS OVER THE NORTHEASTERN CONUS.
HIGH PRESSURE OF CANADIAN ORIGIN LOOKS TO SHUNT MEANDERING FRONT
SOUTH OF THE AREA SUNDAY/SUNDAY NIGHT...WITH THE FRONT LIKELY
BECOMING STALLED ACROSS THE CAROLINAS BEFORE WASHING OUT EARLY NEXT
WEEK. SLIGHT CHC TO LOW CHC POP CONTINUES FOR LATE SAT/SUNDAY FOR
SOME SPOTTY SHRAS DURING THIS PERIOD. GIVEN THAT THE WEAKENING FRONT
WILL REMAIN IN THE AREA MON, HELD ONTO A SLIGHT CHC POP MAINLY SOUTH
OF HIGHWAY 58 CORRIDOR IN S VA/NE NC, AND KEPT FORECAST DRY FARTHER
NORTH. ADDITIONAL LOW CHC POPS ON TUESDAY (MAINLY DIURNALLY DRIVEN)
AS SHORTWAVE ENERGY EMBEDDED IN THE LONGWAVE TROUGH MOVES ACROSS.
DROPPED POPS FOR WEDNESDAY WITH FLATTER/ QUASI-ZONAL FLOW SETTING
UP. FOR TEMPERATURES, EXPECT MAXIMA TO AVERAGE BELOW NORMAL FOR THE
PERIOD, GENERALLY RUNNING IN THE LOW TO MID 80S...THOUGH TEMPS
WILL LIKELY BE CREEPING BACK UP TOWARDS NORMAL AHEAD OF ANOTHER
SLOW MOVING FRONT BY LATER NEXT WEEK. EARLY MORNING LOWS TO
AVERAGE IN THE LOWER TO MIDDLE 60S.
&&
.AVIATION /19Z THURSDAY THROUGH TUESDAY/...
WITH COLD FRONT MOVING THROUGH THIS AFTERNOON AND SHOWERS AND SOME
THUNDERSTORMS DEVELOPING ACROSS THE AREA. SEVERAL SHORT LINES HAVE
FORMED. TRIED TO TIME THEM THROUGH THE TERMINALS. ALSO FOLLOWING
RUC TIMING AS WELL AS THAT SEEMS TO HAVE A GOOD HANDLE ON THE
CURRENT CONVECTION. HRRR TRIES TO BRING CONVECTION OVER NORTHWEST
VIRGINIA INTO CENTRAL AND SOUTHEAST VIRGINIA TOWARD MIDNIGHT. NOT
SURE IF THIS WILL HOLD TOGETHER SO DID NOT INCLUDE IN THE TAFS.
WILL HAVE WATCH FOR LATER CHANGES. COULD SEE SOME FOG DEVELOP
AFTER THESE SHOWERS AS THE COLD FRONT DOES NOT CROSS THE AREA
UNTIL THE EARLY MORNING HOURS. AFTER SUNRISE ON FRIDAY CONDITIONS
WILL BECOME VFR AND REMAIN SO THROUGH MUCH OF SATURDAY. NEXT
SYSTEM APPROACHES SATURDAY AND SUNDAY WITH MORE THUNDERSTORMS
DEVELOPING AND COULD SEE SOME MVFR TO IFR CONDITIONS IN THE
THUNDERSTORMS.
&&
.MARINE...
LATEST OBS REFLECT S-SW WINDS ~15 KT. PRESSURE GRADIENT CONTINUES
TO TIGHTEN OVER THE WATERS AHEAD OF WK LO PRES, WHICH WILL PASS BY
JUST TO OUR NORTH THROUGH TODAY. ASSOCIATED CDFNT WILL PUSH ACROSS
THE WATERS TONIGHT. NOTING WINDS AT LLVL SCA IN THE BAY EARLY THIS
AFTN, AND HV GONE AHEAD AND HOISTED SCA THROUGH 23Z/7PM FOR
FREQUENT WIND GUSTS ~20KT. WINDS WILL DIMINISH EARLY THIS EVENING
AS GRADIENT SLACKENS WITH THE APPROACH OF THE WEAKENING FRONT.
WINDS VEER TO SW TONIGHT...EVENTUALLY BECOMING WNW LATE TNGT/ERY
FRIDAY. FRONT CONTINUES TO WEAKEN TO OUR SOUTH TOMORROW, AS SFC
HI PRES REBUILDS OVR THE WTRS FRI INTO ERY SAT. SUB-SCA CONDS ARE
EXPECTED DURING THIS PERIOD. NEXT CDFNT (BACKDOOR FRONT) DROPS
SOUTH ACROSS THE WATERS SUN. POTENTIAL EXISTS FOR ANOTHER BRIEF
SURGE AHEAD OF THIS FRONT DURING THE DAY SUNDAY. WINDS VEER
AROUND TO THE E-SE MONDAY AS SFC HIGH PIVOTS OFF THE MID-ATLANTIC
COAST LATER MONDAY AND TUESDAY.
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 7 PM EDT THIS EVENING FOR
ANZ630>632-634.
&&
$$
SYNOPSIS...JDM/LSA
NEAR TERM...LSA
SHORT TERM...JDM/MAS
LONG TERM...MAM
AVIATION...JAB
MARINE...ALB/MAM
AREA FORECAST DISCUSSION
NWS GAYLORD MI
138 AM EDT THU AUG 1 2013
.SYNOPSIS...
ISSUED AT 355 PM EDT WED JUL 31 2013
A WEAK COLD FRONT WILL BRING A CHANCE OF SHOWERS AND THUNDERSTORMS
TO NORTHERN MICHIGAN TONIGHT...WITH THE BEST CHANCES FOR EASTERN
UPPER AND NORTHWEST LOWER. A WEAK DISTURBANCE WILL BRING LOW CHANCES
OF SHOWERS TO NORTHEAST LOWER AND THE EASTERN U.P. FOR
THURSDAY...WITH A SLIGHTLY BETTER CHANCE FOR SHOWERS AND
THUNDERSTORMS FOR ALL OF NORTHERN MICHIGAN AGAIN ON FRIDAY...AS
ANOTHER WEAK COLD FRONT MOVES THROUGH THE AREA. HIGH PRESSURE WILL
BRING FAIR WEATHER FOR THIS WEEKEND.
&&
.UPDATE...
ISSUED AT 126 AM EDT THU AUG 1 2013
SCATTERED RAIN SHOWERS WILL HAVE EXITED ALL OF NE LOWER OVER THE
NEXT COUPLE OF HOURS. ALL LIGHTNING GONE. AND REGENERATION OF
ADDITIONAL SHOWERS IS MAYBE POSSIBLE DOWN NEAR THE M-55 CORRIDOR
EAST OF CADILLAC...ALONG EARLIER THUNDERSTORM OUTFLOW...UNTIL 08Z
OR SO. A PERIOD OF FOG/LOW CLOUD IS LIKELY ACROSS MUCH OF NRN
LOWER/EASTERN SECTIONS OF CHIP/MACK..WHERE RAIN HAD FALLEN.
OTHERWISE...A GUSTIER LOW LEVEL FLOW OUT OF THE WNW IS BUILDING IN
FROM THE WEST AND WILL LIKELY MIX OUT ANY FOG/LOW CLOUD FOR THE
LATE HOURS AND INTO THE DAYLIGHT. NEXT WAVE ALOFT ARRIVES BY
MID/LATE MORNING WITH SOME INCREASED CLOUDS AND SLIGHT CHANCE OF
RAIN FOR THE UPCOMING DAY. MORE ON THIS AT 4AM.
UPDATE ISSUED AT 1022 PM EDT WED JUL 31 2013
UPSTREAM COLD FRONT HAS REACHED NRN LAKE MICHIGAN LATE THIS
EVENING...AS THE NEXT WEAK MID LEVEL WAVE SWINGS INTO NRN MICHIGAN
ALONG THE 500 MB TROUGH AXIS. CONVECTIVE LINE THAT IMPACTED ERN
UPR MICHIGAN EARLIER THIS EVENING HAS PUSHED SE INTO FAR NRN LWR
MICHIGAN...AND HAS BUILT FURTHER SOUTHWARD TRYING TO MERGE WITH AN
AREA OF WEAKER CONVECTION GRAZING OUR SRN COUNTIES ATTM. INTENSITY
OF EMBEDDED STORMS HAS FURTHER DIMINISH WITH LOSS OF DIURNAL
INSTABILITY...BUT WITH LOW LEVEL CONVERGENCE AHEAD OF THE FRONT
COMBINED WITH OUR NEXT SHORT WAVE NOW ARRIVING...THUNDERSTORMS DO
CONTINUE TO DEVELOP. EASTWARD PROGRESSION HAS BEEN A BIT SLOWER
THAN PREVIOUSLY EXPECTED...AND HAVE MODIFIED TIMING OF WX/POPS TO
ACCOUNT FOR THIS. CONVECTION WILL CONTINUE ITS SLOW EASTWARD PUSH
INTO THE OVERNIGHT HOURS...WITH PRECIP FINALLY CLEARING OUR CWA
VERY LATE TONIGHT. SVR WX IS STILL NOT EXPECTED FOR THE REST OF
THE NIGHT...BUT DO EXPECT A FEW STORMS WILL PRODUCE WIND GUSTS OF
30 TO 40 MPH AND MAYBE SOME SMALL HAIL.
UPDATE ISSUED AT 720 PM EDT WED JUL 31 2013
WELL-ESTABLISHED LINE OF CONVECTION CONTINUES TO IMPACT THE ERN
HALF OF UPPER MICHIGAN AHEAD OF AN APPROACHING COLD FRONT...AND
ENHANCED BY A MODEST SHORT WAVE AND LOCALIZED LAKE BREEZE
CONVERGENCE. OVERALL INTENSITY OF THIS CONVECTION HAS WEAKENED
OVER THE PAST HOUR OR SO AS THE GUST FRONT AHEAD OF THE MAIN LINE
LIMITED THE INFLOW. MAIN LINE HAS ALSO MOVED OUT OF THE AREA OF
BEST LAKE BREEZE CONVERGENCE. LATEST NAM AND 3KM HRRR SHOWS THIS
AREA OF CONVECTION WILL TRY TO MERGE (TO A DEGREE) WITH ANOTHER
AREA OF WEAKER CONVECTION NOW MOVING INTO OUR FAR SW CWA OUT OF
CENTRAL LAKE MICHIGAN...AND WILL THEN SWEEP EASTWARD THRU NRN LWR
MICHIGAN DURING THE BALANCE OF THE EVENING. OVERALL INTENSITY...AND
LIKELY AREAL COVERAGE AS WELL...SHOULD CONTINUE TO DIMINISH WITH
LOSS OF DIURNAL INSTABILITY THIS EVENING. WILL CERTAINLY CONTINUE
TO KEEP A CLOSE EYE ON THE CONVECTIVE LINE MOVING OUT OF ERN UPR
MICHIGAN AND INTO THE STRAITS FOR ANY FURTHER STRENGTHENING...BUT
DO NOT EXPECT ANY SIGNIFICANT THREAT FOR SEVERE STORMS.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 355 PM EDT WED JUL 31 2013
FAST FLOW PATTERN CONTINUES ACROSS THE NORTHERN LAKES THIS
AFTERNOON...WITH LEAD SHORTWAVE TROUGH DAMPENING OUT AND MOVING OFF
TO THE EAST...WITH SECONDARY STRONGER SHORTWAVE AND ATTENDANT COLD
FRONT CUTTING INTO THE NORTHWEST LAKES. TOOK A WHILE...BUT
CONVECTION IS STARTING TO FIRE WITH THE LATTER FEATURES...MOST
NOTABLY ACROSS CENTRAL/EASTERN UPPER MICHIGAN WHERE A BROKEN LINE OF
THUNDERSTORMS HAS DEVELOPED IN THE LAST FEW HOURS. NOT MUCH TAKING
PLACE SOUTH OF THE BIG BRIDGE...WITH CLOUD COVER AND LACK OF
DYNAMICS IN WAKE OF FIRST WAVE PREVENTING ANY SHOWER/STORM
DEVELOPMENT. FORECAST CONCERNS CENTER ON SHOWER/STORM POTENTIAL THIS
EVENING...WITH ADDITIONAL LIGHT SHOWER CHANCES NEEDING ADDRESSING
FOR THURSDAY.
UPSTREAM COLD FRONT AND MID LEVEL SUPPORT EXPECTED TO CROSS NORTHERN
MICHIGAN THIS EVENING. JUST ENOUGH FORCING/LOW LEVEL CONVERGENCE TO
CONTINUE TO SUPPORT SHOWER AND STORM DEVELOPMENT ALONG THESE
FEATURES...AND WOULD EXPECT UPSTREAM ACTIVITY TO CONTINUE TO SLOWLY
CONGEAL THIS AFTERNOON. LACK OF PRE-FRONTAL DESTABILIZATION SHOULD
KEEP BOTH COVERAGE AND INTENSITY IN CHECK...AND WILL SIMPLY SPREAD A
BROKEN LINE OF SHOWERS/EMBEDDED STORMS FROM NORTHWEST TO SOUTHEAST
ACROSS THE REGION TONIGHT. ORGANIZED SEVERE WEATHER DEFINITELY NOT
EXPECTED...BUT SUPPOSE AN ISOLATED STRONGER STORM IS POSSIBLE
THROUGH THE REMAINDER OF THIS AFTERNOON...ESPECIALLY ACROSS EASTERN
UPPER MICHIGAN. SHOWER THREAT EXPECTED TO END DURING THE EARLY
MORNING HOURS. POST-FRONTAL DRYING NOT OVERLY AGGRESSIVE...AND WITH
EXPECTED RAINS...FEEL PATCHY/AREAS OF FOG A GOOD BET DURING THE
EARLY MORNING HOURS.
THURSDAY EXPECTED TO START OFF DRY...WITH NEXT LOW AMPLITUDE FAST
MOVING WAVE SPREADING ACROSS OUR AREA DURING THE LATE MORNING AND
EARLY AFTERNOON. MOISTURE PROFILES LIMITED...AS IS ANY SPECIFIC LOW
LEVEL CONVERGENCE BOUNDARY (PERHAPS WEAK LAKE INFLUENCED BOUNDARY
SOUTH SIDE OF EASTERN UPPER). THAT SAID...MODEL DERIVED SOUNDINGS
NOT TOO TERRIBLE FOR SHOWER DEVELOPMENT...WITH STEEP LOW LEVEL LAPSE
RATES AND PROJECTED ML CAPE NEAR 500 J/KG. ABOVE PROBABLY A TOUCH
AGGRESSIVE...AND WITH NO WELL DEFINED LOW LEVEL CONVERGENCE
BOUNDARIES...WILL TEMPER INHERITED POPS SOME...FEATURING JUST LOW
CHANCE IN CLIMATOLOGICALLY FAVORED AREAS OF EASTERN UPPER AND
NORTHEAST LOWER MICHIGAN. WILL KEEP THUNDER OUT OF THE EQUATION FOR
NOW. TEMPERATURES REMAINING BELOW NORMAL...WITH HIGHS IN THE LOWER
AND MIDDLE 70S.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 355 PM EDT WED JUL 31 2013
THURSDAY NIGHT AND FRIDAY...A COLD FRONT ASSOCIATED WITH A STORM
SYSTEM OVER HUDSON BAY...WILL PUSH INTO THE WRN LAKES THURSDAY
EVENING BEFORE SLOWLY SWEEPING OVER THE STATE FRIDAY. HIGH PRESSURE
WILL THEN QUICKLY BUILD BACK INTO THE UPPER MIDWEST AND WESTERN
GREAT LAKES FRIDAY NIGHT...AS THE COLD FRONT EXITS EAST OF THE
REGION. MODEL SOUNDINGS AND MSTR PROGS SHOWING LIMITED MSTR WILL
HINDER PCPN AMOUNTS AND CHC`S OVR NRN MI THURSDAY NIGHT. HOWEVER
THERE WILL BE SOME MSTR INCREASE OVER THE CWA FRIDAY JUST IN ADVANCE
OF THE COLD APPROACHING FRONT. 850/500MB RH WILL INCREASE FROM
AROUND 40PCT THURSDAY NIGHT TO 80PCT FRIDAY...WHILE MODEL SOUNDINGS
SHOW PWAT VALUES INCREASING TO 90PCT FRIDAY. 850/500MB QVECTORS
SHOWING LIMITED CONVERGENCE WITH APPROACHING COLD FRONT...CONFINED
MAINLY TO RIGHT ALONG THE BOUNDARY. OVERALL WILL KEEP MOST OF THE
FCST AREA DRY THURSDAY NIGHT...WITH BETTER CHANCES OF RAIN FRIDAY AS
BOUNDARY MOVES ACRS LAKE MICHIGAN. WILL MENTION HIGH TEMPS IN THE
MID 70S OVR THE CWA AIDED IN PART BY SOME SUN AND SOUTHWEST FLOW.
FOR THE WEEKEND...COOL UNSEASONAL CONDITIONS ARE EXPECTED ACRS THE
GREAT LAKES FOR THE FIRST WEEKEND IN AUGUST. AT UPPER LEVELS...
WHICH WILL RESEMBLE MORE THAT OF MID WINTER INSTEAD OF MID
SUMMER...A 500MB LOW WILL BECOME CENTERED OVER HUDSON BAY THROUGH
THE WEEKEND. WHILE AT THE SURFACE...AN AREA OF CANADIAN HIGH
PRESSURE WILL BUILD INTO THE NRN PLAINS AND GREAT LAKES THRU THE
WEEKEND. TEMPS WILL TREND BELOW NORMAL THRU SUNDAY...AS THE HUDSON
BAY 500MB LOW FORCES COLD 850MB TEMPS INTO THE REGION. 850MB TEMPS
WILL COOL FROM AROUND 11C FRIDAY TO BTWN 6C AND 8C BY SUNDAY.
CURRENT TRENDS CONT TO INDICATE DRY CONDS OVER NRN MI THIS WEEKEND
THOUGH SOME LAKE INFLUENCES ARE POSSIBLE. SUSPECT THE DRY AIR MOVING
INTO THE GREAT LAKES WILL LIMIT LAKE EFFECTS TO MAINLY CLOUDS...AS
850/500MB RH DIMINISHES TO UNDER 40 PCT. WILL KEEP AFTN TEMPS COOL
THROUGH THE WEEKEND...IN THE UPPER 60S TO LOWER 70S ACRS NRN MI...
AS 850MB TEMPS FALL TO AROUND 6C.
MONDAY THROUGH WEDNESDAY...UNSEASONABLY COOL TREND TO LINGER ACRS
THE NORTHERN GREAT LAKES REGION THRU MID WEEK...AS BROAD UPPER
TROUGH FROM THE WEEKEND LINGERS ACRS THE GREAT LAKES. 850MB TEMPS
LINGER AROUND 6C TO BEGIN THE UPCOMING WORK WEEK...KEEPING AFTN HIGHS
IN THE LOWER 70S. SMALL CHANCES OF SHOWERS WILL EXIST THROUGH THE
PERIOD...AS HIGH PRESSURE FROM THE WEEKEND EXITS EAST AND A WEAK
SYSTEM TRIES TO ORGANIZE OVER THE NRN PLAINS AND UPPER MIDWEST.
PCPN AMOUNTS AND CHC WILL BE HINDERED GREATLY BY LIMITED MOISTURE
AS 850/500MB RH REMAINS AROUND 60PCT.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 126 AM EDT THU AUG 1 2013
THUNDERSTORM OUTFLOW FROM EARLIER MORE VIGOROUS ACTIVITY HAS
SHOVED DOWN INTO TVC AND TRYING TO MAKE IT TO MBL. THIS HAS
ALREADY RESULTED IN MVFR OVC CIGS AT TVC...WHICH MAY IMPACT MBL
BUT CONFIDENCE IS NOT HIGH ENOUGH TO INCLUDE THE CIG SINCE THE SW
PUSH OF THIS OUTFLOW/COOLER AIR...IS SLOWING ACROSS THE GTV BAY
AREA. THIS CIG WILL LIKELY MIX OUT OVER THE NEXT COUPLE OF HOURS
WITH INCREASED WNW BL FLOW BEHIND A COLD FRONT THAT HAS PASSED
THROUGH NW LOWER. TOOK OUT ALL MENTION OF FOG FOR THE BALANCE OF
THE NIGHT. THIS IS NOT SO TRUE FOR PLN/APN...WHERE THE RAINFALL
OCCURRED. CAN SEE AN HOUR OR TWO OF MVFR FOG/CIGS BEFORE THE BL
FLOW INCREASES ENOUGH TO MIX THIS OUT. SHOULD BE A PERIOD OF
FAIRLY CLEAR SKIES UNTIL MORNING...WHERE SOME INCREASED MID LEVEL
CLOUD AND FEW-SCT CU FIRES OFF AHEAD OF NEXT APPROACHING
DISTURBANCE ALOFT AND COLD FRONT/SFC TROUGH. BELIEVE THAT A FEW
STRAY SHOWERS WILL BE AROUND TOMORROW LATE MORNING/AFTERNOON WITH
THE ARRIVAL OF THE FRONT/TROUGH AND COOLING TEMPS ALOFT/STEEPER
MID LEVEL LAPSE RATES. BEST SHOT AT APN WHERE A VCSH HAS BEEN
INTRODUCED.
ADDITIONAL ISOLATED/SCATTERED SHOWERS/POSSIBLE THUNDER...WILL
LIKELY FIRE OFF AROUND GREEN BAY...AND THERE IS SOME EVIDENCE THAT
ANOTHER DISTURBANCE WILL BE WORKING IN OVER THE WESTERN GREAT
LAKES THAT COULD HELP SUSTAIN ISOLATED ACTIVITY OVER LAKE
MICHIGAN...AND INTO THE TAF SITES OVERNIGHT THURSDAY NIGHT.
CERTAINLY NOT ENOUGH CONFIDENCE TO WARRANT A VCSH MENTION.
WINDS WILL BE A TAD GUSTY OUT OF THE WNW/NW THURSDAY (UPPER TEENS
IN KNOTS)...WITH SLIGHTLY BACKING WINDS AND NO MORE GUSTS HEADING
INTO THE EVENING.
&&
.MARINE...
ISSUED AT 355 PM EDT WED JUL 31 2013
LIGHT TO MODERATE SOUTHWEST FLOW WILL VEER WEST OVERNIGHT
BEHIND COLD FRONT PASSAGE. SOME SHOWERS/STORMS POSSIBLE ALONG THIS
FRONT...PERHAPS PRODUCING SOME LOCALIZED GUSTY WINDS. SUB ADVISORY
WINDS EXPECTED TO CONTINUE INTO THIS WEEKEND.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...NONE.
LM...NONE.
LS...NONE.
&&
$$
UPDATE...SD
SYNOPSIS...NS
SHORT TERM...MB
LONG TERM...SR
AVIATION...SD
MARINE...MB
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
320 PM CDT THU AUG 1 2013
.DISCUSSION...
ACTIVE WEATHER EXPECTED THIS EVENING AS A MATURE MCS ACROSS
NORTHERN NEBRASKA SHOULD ROLL EAST SOUTHEAST. SEVERE WATCH
REMAINS IN EFFECT FOR NORTHEAST NEBRASKA AND NORTHWEST IOWA...AND
A TORNADO WATCH IN EFFECT FOR MUCH OF NORTH CENTRAL NEBRASKA. HOP
WRF AND RAP SEEM TO HAVE THE BEST HANDLE ON DEVELOPING CONVECTION...
THUS WILL HAVE HIGH POPS THIS EVENING WITH A SEVERE THREAT. HAVE
ISSUED A COUPLE OF SEVERE WARNINGS IN EXTREME NORTHEAST NEBRASKA...
BUT WE HAVEN`T BEEN ABLE TO GET ANY HAIL REPORTS BIGGER THAN
DIME TO NICKEL SIZE. EFFECTIVE SHEAR REMAINS QUITE HIGH AT 50 TO
60 KNOTS...BUT MID LEVEL LAPSE RATES ARE SLIGHTLY MARGINAL. WILL
ALSO CONTINUE TO MONITOR TRENDS AND ISSUE WARNINGS AS NECESSARY
FOR LARGE HAIL AND DAMAGING WINDS WITHIN THE STRONGEST CORES...AND
MAY HAVE TO EVENTUALLY EXTEND THE WATCH FURTHER EAST/SOUTHEAST
TOWARD THE I80 CORRIDOR IN TIME. THE BACK EDGE OF THE PRECIPITATION
WILL PROBABLY STILL BE IN THE AREA FRIDAY MORNING MOVING OUT OF
SOUTHEAST NEBRASKA AND SOUTHWEST IOWA. THE AFTERNOON MAY BE MOSTLY
DRY...ALTHOUGH THERE DOES APPEAR TO BE ANOTHER WEAK SURGE OF
MOISTURE MOVING SOUTH...WHICH COULD BRING A SLIGHT CHANCE OF
STORMS FRIDAY NIGHT.
BY SATURDAY...HIGH PRESSURE NOSING SOUTH OUT OF THE DAKOTAS SHOULD
KEEP SATURDAY DRY AND SLIGHTLY COOLER. THIS NORTHEASTERLY FLOW
BECOMES EAST SATURDAY NIGHT. AT THE SAME TIME...THERE IS ANOTHER
WAVE MOVING OUT OF THE ROCKIES...SO IT WILL BE A BATTLE OF HOW FAR
EAST THIS SYSTEM CAN GET BY DAYBREAK SUNDAY...VERSUS THE DRY
EASTERLY FLOW WITH HIGH PRESSURE ACROSS THE MID MISSISSIPPI RIVER
VALLEY. CHANCES SHOULD SPREAD ACROSS THE FORECAST AREA SUNDAY
THOUGH...BUT MAY STILL STRUGGLE TO MOVE INTO WESTERN IOWA. WAVE
COULD MOSTLY BE EAST SOUTHEAST OF THE AREA SO SHOULD BE MOSTLY DRY
SUNDAY NIGHT.
FOR THE EXTENDED FORECAST...THE REGION REMAINS IN PESKY NORTHWEST
FLOW. FORECAST CHALLENGES REMAIN TRYING TO TIME WEAK WAVES INTO
THE AREA...THUS OVERALL FORECAST CONFIDENCE REMAINS LOW. TOWARD
THE END OF THE PERIOD...ANOTHER FRONT SETTLING SOUTH COULD BRING
SOME COOLER TEMPS TO THE REGION BY THURSDAY...BUT COULD ALSO SHUNT
ANY PRECIP THREAT OUT OF THE AREA AS WELL.
DEWALD
&&
.AVIATION...18Z TAFS FOR KOFK...KOMA AND KLNK.
SCATTERED TSTMS ARE EXPECTED TO DEVELOP AND MOVE ACROSS THE
REGION...POSSIBLY HITTING TAF SITES LATE THIS AFTERNOON AND INTO
THE EVENING HOURS. CONDITIONS SHOULD REMAIN VFR FOR THE MOST
PART...HOWEVER SOME OF THESE STORMS COULD CONTAIN LARGE HAIL AND
DAMAGING WINDS AND MVFR TO IFR CONDITIONS.
KERN
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS HASTINGS NE
310 PM CDT THU AUG 1 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 300 PM CDT THU AUG 1 2013
MORNING MAP ANALYSIS INDICATES MID TO UPPER LEVEL RIDGING OVER THE
WESTERN CONUS...WITH A TROUGH OVER THE EAST. MID TO UPPER LEVEL JET
ENERGY EXTENDS FROM THE WEST-CENTRAL CONUS...NORTHEAST INTO THE
NORTHERN ROCKY MOUNTAIN RANGE...AND THEN SOUTHEAST ACROSS PORTIONS
OF THE PLAINS AND MISSISSIPPI VALLEY...AND FINALLY EAST/NORTHEAST
INTO THE EASTERN CONUS. NORTHWESTERLY MID TO UPPER LEVEL FLOW
PERSISTS OVER THE CENTRAL PLAINS AS A RESULT. A ~110KT UPPER LEVEL
JET STREAK IS ALSO NOTED EXTENDING FROM THE NORTHERN
PLAINS...SOUTHEAST INTO THE MID-MISSISSIPPI VALLEY. MID TO UPPER
LEVEL FLOW MAXES OUT AT AROUND 100KTS NEAR 200MB PER RAP ANALYSIS
AND 12Z SOUNDING DATA FROM KOAX. AT THE SURFACE A RIDGE OF HIGH
PRESSURE EXTENDS FROM THE MISSOURI RIVER VALLEY...SOUTH/SOUTHEAST
INTO PORTIONS OF THE MID-MISSISSIPPI VALLEY. LEE SIDE TROUGHING ALSO
EXTENDS FROM SOUTHEASTERN WYOMING INTO EASTERN COLORADO AND AS A
RESULT...SOUTHERLY LOW LEVEL FLOW IS INFILTRATING OUR CWA.
FOR THE REST OF THIS AFTERNOON AND EVENING...CONTINUED SOUTHERLY LOW
LEVEL FLOW...ENHANCED BY THE DEVELOPMENT OF A 25-30KT 850MB JET
STREAK...WILL PROMOTE INCREASING THERMAL ADVECTION ACROSS MUCH OF
OUR AREA. ISENTROPIC UPGLIDE AND
SATURATION...PRIMARILY ALONG THE 310-320K SURFACES...IS EXPECTED TO
PROMOTE PRECIPITATION PRODUCTION ACROSS THE AREA. INCREASED VALUES
OF LOW LEVEL MOISTURE SHOULD CONTINUE PROMOTING DECENT VALUES OF
POTENTIAL INSTABILITY...WITH THE NAM AND OPERATIONAL GFS BOTH
SUGGESTING MUCAPE VALUES NEAR 3000J/KG ACROSS MUCH OF THE AREA. IN
ADDITION TO THE POTENTIAL INSTABILITY...DEEP LAYER BULK SHEAR VALUES
ON THE ORDER OF 40-50KTS IS ALSO EXPECTED. GIVEN ALL THIS...SEVERE
WEATHER REMAINS POSSIBLE THIS AFTERNOON INTO THIS EVENING...WITH
LARGE HAIL AND STRONG THUNDERSTORM WIND GUSTS BEING THE PRIMARY
SEVERE WEATHER THREATS. IN ADDITION THE HAIL AND WIND THREAT
HOWEVER...FORECAST PROXIMITY SOUNDINGS FROM VARIOUS MODELS SUGGEST A
SIGNIFICANTLY VEERING LOW LEVEL WIND PROFILE THUS HELPING PROMOTE
SRH VALUES NEAR 200M^2/S^2 ACROSS PORTIONS OF OUR CWA. GIVEN
THIS...WILL ALSO CONTINUE THE TORNADO MENTION IN THE HWO.
GUIDANCE SUGGESTS THE AFOREMENTIONED THERMAL ADVECTION SHOULD HELP
MAINTAIN PRECIPITATION PRODUCTION ACROSS THE AREA TONIGHT...WITH
MUCH OF THIS ACTIVITY MOVING OFF TO EAST BY EARLY FRIDAY MORNING. IT
WOULD APPEAR AS THOUGH THE SEVERE WEATHER THREAT SHOULD DIMINISH
HEADING INTO THE OVERNIGHT HOURS. THAT BEING SAID...WITH A
PERSISTENT SOUTHERLY LOW LEVEL WIND FIELD...INCREASING SIGNIFICANTLY
ABOVE THE BOUNDARY LAYER PRIMARILY DUE TO A ~50KT LOW LEVEL
JET...MAY HELP PROMOTE NOCTURNAL MCS DEVELOPMENT. WILL CONTINUE THE
MENTION OF SEVERE WEATHER ACROSS THE AREA THROUGH THE OVERNIGHT
HOURS AS A RESULT...BUT THE DETAILS OF ANY POTENTIAL MCS DEVELOPMENT
WILL NOT LIKELY BECOME ANY MORE CLEAR UNTIL LATER TONIGHT.
THE PRIMARY AXIS OF THERMAL ADVECTION SHOULD DEPART THE AREA TO THE
EAST ON FRIDAY...THUS ALLOWING FOR DECREASING PRECIPITATION CHANCES.
THAT BEING SAID...MID LEVEL PERTURBATIONS MOVING OVER THE AREA WITHIN
THE MEAN FLOW SHOULD STILL PROMOTE ENOUGH OMEGA FOR FURTHER
PRECIPITATION PRODUCTION ACROSS PORTIONS OF OUR CWA STARTING FRIDAY
AFTERNOON. SHOULD THUNDERSTORM ACTIVITY BE REALIZED FRIDAY
AFTERNOON...THEN SEVERE WEATHER COULD ONCE AGAIN BE REALIZED AS
GUIDANCE SUGGESTS MUCAPE VALUES NEAR 3000J/KG WILL ACCOMPANY DEEP
LAYER BULK SHEAR VALUES OF 30-40KTS. GIVEN ALL THIS...WILL GO AHEAD
AND OUTLOOK SEVERE WEATHER FOR FRIDAY AS WELL.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 300 PM CDT THU AUG 1 2013
FORECAST CONCERNS MAINLY FOCUSED ON THUNDERSTORMS.
MODELS ARE IN GOOD AGREEMENT THAT THE NORTHWEST FLOW REGIME WILL
PERSIST THROUGH THE PERIOD. THUS...EXPECT A PERIOD OF UNSETTLED
WEATHER WITH NORMAL OR BELOW NORMAL TEMPERATURES.
AT THE SURFACE...A BROAD AREA OF LOW PRESSURE ON THE LEE SIDE OF
THE ROCKIES WILL ANCHOR A WEAK FRONTAL BOUNDARY THAT WILL
OSCILLATE FROM KS TO SD THROUGH THE PERIOD. THE LOCATION OF THIS
BOUNDARY WILL BE THE FOCUS OF AFTERNOON CONVECTIVE INITIATION. THEN
STORMS SHOULD DRIFT SOUTH AND EAST THROUGH THE EVENING HOURS AS AN
MCS. THERE WILL BE GOOD INSTABILITY AND MOISTURE AVAILABLE...SO
SEVERE STORMS CAN NOT BE RULED OUT.
ALOFT...THE NORTHWEST FLOW WILL ALLOW FREQUENT AND WEAK WAVES TO
MOVE OVER THE AREA. THIS WILL OFFER ENOUGH SUPPORT TO GET INITIATE
THE CONVECTION.
TOWARDS THE END OF THE PERIOD (THURSDAY) A STRONGER COOL FRONT IS
FORECAST TO MOVE SOUTH ACROSS THE AREA. IF THIS
OCCURS...TEMPERATURES WILL BE 10 TO 20 DEGREES BELOW NORMAL AND IT
WILL BE DRY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 145 PM CDT THU AUG 1 2013
VFR CONDITIONS FORECAST THROUGH THE NEXT 24 HOURS.
SHOWER AND THUNDERSTORM ACTIVITY IS EXPECTED TO DEVELOP AND MOVE
ACROSS THE REGION THIS AFTERNOON AND INTO THE OVERNIGHT HOURS.
SOME OF THIS ACTIVITY COULD CONTAIN VERY STRONG WIND GUSTS. FOR
NOW WILL GO WITH VCTS 20-12Z AND REFINE SHOWER/THUNDERSTORM TIMING
AFTER CONFIDENCE INCREASES FOLLOWING DEEP CONVECTIVE DEVELOPMENT.
THE SYNOPTIC SURFACE WIND WILL REMAIN FROM THE SOUTH/SOUTHEAST
THROUGH THE TAF PERIOD AT AROUND 08KTS...BUT AGAIN A STRONG AND
VARIABLE WIND WILL BE POSSIBLE IN AND NEAR THUNDERSTORM ACTIVITY.
VISIBILITY RESTRICTION IS NOT CURRENTLY FORECAST...BUT SOME
VISIBILITY RESTRICTION IN RAIN WILL BE POSSIBLE SHOULD SHOWER AND
THUNDERSTORM ACTIVITY INFILTRATE THE AREA.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...BRYANT
LONG TERM...EDDY
AVIATION...BRYANT
AREA FORECAST DISCUSSION
NWS HASTINGS NE
145 PM CDT THU AUG 1 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 346 AM CDT THU AUG 1 2013
IN THE UPPER LEVELS WE ARE STILL IN GENERALLY NORTHWESTERLY FLOW
WITH A RIDGE LOCATED TO THE WEST CENTERED OVER THE ROCKIES. AT THE
SURFACE WE HAVE HIGH PRESSURE SLIGHTLY TO OUR NORTHEAST WITH A GOOD
TONGUE OF MOISTURE REACHING UP THROUGH THE CENTRAL PLAINS. THIS
MOISTURE IS ALSO APPARENT AT 850HPA WITH DEWPOINTS NEAR 15 DEGREES.
CURRENT KUEX RADAR SHOWS A FEW THUNDERSTORMS ENTERING THE NORTHWEST
PORTION OF OUR CWA. THE RAP MODEL...AND TO SOME DEGREE THE WRF
MODELS...SEEMED TO HAVE THE BEST HANDLE FOR THIS TIME PERIOD WHICH
MAINTAINS CHANCES OF PRECIPITATION FOR THE WESTERN PART OF OUR CWA
INTO THE MORNING.
MAIN CONCERN FOR THIS FORECAST IS CONVECTION AND SEVERE WEATHER
POTENTIAL FOR TODAY. THE SURFACE HIGH WILL MOVE OFF TO THE EAST
AS A LOW DEVELOPS TO THE WEST. AS THE HIGH MOVES OFF...INCREASINGLY
SOUTHERLY FLOW WILL BRING IN MORE MOISTURE WITH AFTERNOON DEW
POINTS IN THE MID TO UPPER 60S. A WARM FRONT WILL LIFT NORTH
ACROSS NEBRASKA REACHING CENTRAL NEBRASKA THIS AFTERNOON. MODELS
ARE INDICATING INSTABILITY INCREASING TO 2000 TO 3000 J/KG ALONG
WITH DEEP LAYER SHEAR OF 40 TO 50 KTS. THESE PARAMETERS ARE
SUFFICIENT FOR SUPERCELL DEVELOPMENT ESPECIALLY IN THE VICINITY OF
THE WARM FRONT. STORMS WHICH DEVELOP WILL BE CAPABLE OF PRODUCING
VERY LARGE HAIL...STRONG WINDS...AND EVEN TORNADOES NEAR THE
BOUNDARY. PRECIPITABLE WATERS THIS AFTERNOON AVERAGE 1.50 INCHES AND ARE
130 PERCENT OF NORMAL. LOCALLY HEAVY RAINFALL IN EXCESS OF AN INCH
OR TWO IS POSSIBLE. CONVECTION THAT DEVELOPS IN THE AFTERNOON AND
EVENING IS EXPECTED TO PERSIST TONIGHT AS THE LLJ IS IN EXCESS OF
40 TO 45 KTS. EVEN WITH THIS POTENTIAL FOR STRONG
STORMS...CONFIDENCE IS STILL NOT HIGH FOR WIDESPREAD
PRECIPITATION AS MODELS ARE NOT CONSISTENT WITH DEVELOPMENT/QPF.
WENT WITH SCATTERED POPS THROUGHOUT THE DAY AND WILL NEED TO MONITOR
THE TREND AS THE DAY PROGRESSES AND CONVECTION UNFOLDS.
TEMPERATURES TODAY ARE DEPENDENT ON CLOUD COVER. GENERALLY WE
SHOULD SEE HIGH TEMPS A FEW DEGREES WARMER THAN YESTERDAY DUE TO
THE INCREASED MIDLEVEL TEMPS. REMAINING CLOUD COVER IN THE MORNING
AND CONVECTION IN THE AFTERNOON MIGHT REDUCE DAYTIME HEATING...BUT
BREAKS IN CLOUD COVER COULD ALLOW TEMPERATURES TO APPROACH THE LOW
90S...ESPECIALLY IN THE SOUTHWEST PART OF THE CWA.
LOWS TONIGHT ARE EXPECTED TO BE IN THE MID TO UPPER 60S IN THE
WARMER AIR MASS. THESE LOW TEMPS ARE NEAR AVERAGE FOR THIS TIME OF
YEAR.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 346 AM CDT THU AUG 1 2013
FRIDAY MORNING THROUGH WEDNESDAY. CONCERN CONTINUES TO
REVOLVE AROUND PERIODIC CHANCES FOR RAIN DURING THE ENTIRE EXTENDED
PERIOD.
STARTING OUT FRIDAY MORNING IN THE UPPER LEVELS...MODELS STILL
CONSISTENT IN SHOWING ONE CLOSED LOW OVER THE PACIFIC NORTHWEST AND
ANOTHER ONE OVER NORTHERN ONTARIO. THESE CONTINUE TO DAMPEN THE HIGH
OVER THE SOUTHERN PLAINS. IMPRESSIVE NORTHERN STREAM FOR THIS TIME
OF YEAR WHICH WILL AFFECT THE NORTHERN HALF OF THE CONUS. AT THE
SURFACE...EXPECT LOW PRESSURE OVER SOUTHWEST NEBRASKA WITH A WARM
FRONT EXTENDING SOMEWHERE ACROSS THE CWA. BELIEVE ANY OVERNIGHT
CONVECTION SHOULD HAVE WORKED ITS WAY EAST OF THE CWA BY 12Z FRIDAY
AND WILL TAKE OUT LOW POPS THAT WERE PREVIOUSLY IN THE EASTERN PART
OF OUR AREA. WILL ALSO LEAVE ANY RAIN CHANCES OUT DURING THE DAYTIME
ON FRIDAY AS MOST OF THE CONVECTION THE PAST FEW WEEKS HAS OCCURRED
DURING THE EVENING AND OVERNIGHT TIME FRAME. SHOULD STILL BE IN THE
WARM SECTOR FOR MOST OF THE AREA ON FRIDAY BUT BY SATURDAY THE
SURFACE LOW PUSHES SOUTH AND OUR WINDS BECOME MORE NORTHEASTERLY
WITH SOME COOLER AIR PUSHING IN. HIGHS ON SAT SHOULD BE ABOUT 5
DEGREES BELOW THOSE ON FRIDAY.
AS HAS BEEN NOTED IN PREVIOUS AFDS...TOUGH TO TIME ANY SHORTWAVE
TROUGHS MOVING OVER THE AREA MORE THAN A DAY OR TWO OUT. HOWEVER
BOTH THE LATEST GFS AND EC OPERATIONAL RUNS SIMILAR IN SLIDING ONE
OF THESE WAVES THROUGH THE RIDGE AND OVER US SATURDAY NIGHT. FOR
THIS REASON WILL UP RAIN CHANCES SAT NIGHT AND CONTINUE INTO SUNDAY.
AFTER THAT WE CONTINUE WITH NORTHWEST FLOW AS THE BIG PICTURE POINTS
TO TROUGHING IN THE EAST AND WEST CONUS WITH WEAK RIDGING IN THE
CENTRAL THROUGH AT LEAST THE MIDDLE PART OF NEXT WEEK. THESE LEAVES
US OPEN TO ADDITIONAL DISTURBANCES MOVING THROUGH SO WILL CONTINUE
WITH 20-30 POPS.
IN REGARDS TO SEVERE...DEEP LAYER SHEAR LOOKS FAVORABLE AT LEAST
THROUGH THE WEEKEND WITH 0-6 KM BULK SHEAR PROGGED FROM 25 KT IN
THE SOUTHERN CWA TO 40 KT IN THE NORTH. INSTABILITY ALSO LOOKS OK.
ONE ISSUE THIS TIME OF YEAR IS WILL THERE BE ANY CAPPING TAKING
PLACE. MODELS DO HINT AT THAT AND WILL BE SOMETHING TO WATCH.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 145 PM CDT THU AUG 1 2013
VFR CONDITIONS FORECAST THROUGH THE NEXT 24 HOURS.
SHOWER AND THUNDERSTORM ACTIVITY IS EXPECTED TO DEVELOP AND MOVE
ACROSS THE REGION THIS AFTERNOON AND INTO THE OVERNIGHT HOURS.
SOME OF THIS ACTIVITY COULD CONTAIN VERY STRONG WIND GUSTS. FOR
NOW WILL GO WITH VCTS 20-12Z AND REFINE SHOWER/THUNDERSTORM TIMING
AFTER CONFIDENCE INCREASES FOLLOWING DEEP CONVECTIVE DEVELOPMENT.
THE SYNOPTIC SURFACE WIND WILL REMAIN FROM THE SOUTH/SOUTHEAST
THROUGH THE TAF PERIOD AT AROUND 08KTS...BUT AGAIN A STRONG AND
VARIABLE WIND WILL BE POSSIBLE IN AND NEAR THUNDERSTORM ACTIVITY.
VISIBILITY RESTRICTION IS NOT CURRENTLY FORECAST...BUT SOME
VISIBILITY RESTRICTION IN RAIN WILL BE POSSIBLE SHOULD SHOWER AND
THUNDERSTORM ACTIVITY INFILTRATE THE AREA.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...MANGELS/FAY
LONG TERM...EWALD
AVIATION...BRYANT
AREA FORECAST DISCUSSION
NWS HASTINGS NE
533 AM CDT THU AUG 1 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 346 AM CDT THU AUG 1 2013
IN THE UPPER LEVELS WE ARE STILL IN GENERALLY NORTHWESTERLY FLOW
WITH A RIDGE LOCATED TO THE WEST CENTERED OVER THE ROCKIES. AT THE
SURFACE WE HAVE HIGH PRESSURE SLIGHTLY TO OUR NORTHEAST WITH A GOOD
TONGUE OF MOISTURE REACHING UP THROUGH THE CENTRAL PLAINS. THIS
MOISTURE IS ALSO APPARENT AT 850HPA WITH DEWPOINTS NEAR 15 DEGREES.
CURRENT KUEX RADAR SHOWS A FEW THUNDERSTORMS ENTERING THE NORTHWEST
PORTION OF OUR CWA. THE RAP MODEL...AND TO SOME DEGREE THE WRF
MODELS...SEEMED TO HAVE THE BEST HANDLE FOR THIS TIME PERIOD WHICH
MAINTAINS CHANCES OF PRECIPITATION FOR THE WESTERN PART OF OUR CWA
INTO THE MORNING.
MAIN CONCERN FOR THIS FORECAST IS CONVECTION AND SEVERE WEATHER
POTENTIAL FOR TODAY. THE SURFACE HIGH WILL MOVE OFF TO THE EAST
AS A LOW DEVELOPS TO THE WEST. AS THE HIGH MOVES OFF...INCREASINGLY
SOUTHERLY FLOW WILL BRING IN MORE MOISTURE WITH AFTERNOON DEW
POINTS IN THE MID TO UPPER 60S. A WARM FRONT WILL LIFT NORTH
ACROSS NEBRASKA REACHING CENTRAL NEBRASKA THIS AFTERNOON. MODELS
ARE INDICATING INSTABILITY INCREASING TO 2000 TO 3000 J/KG ALONG
WITH DEEP LAYER SHEAR OF 40 TO 50 KTS. THESE PARAMETERS ARE
SUFFICIENT FOR SUPERCELL DEVELOPMENT ESPECIALLY IN THE VICINITY OF
THE WARM FRONT. STORMS WHICH DEVELOP WILL BE CAPABLE OF PRODUCING
VERY LARGE HAIL...STRONG WINDS...AND EVEN TORNADOES NEAR THE
BOUNDARY. PRECIPITABLE WATERS THIS AFTERNOON AVERAGE 1.50 INCHES AND ARE
130 PERCENT OF NORMAL. LOCALLY HEAVY RAINFALL IN EXCESS OF AN INCH
OR TWO IS POSSIBLE. CONVECTION THAT DEVELOPS IN THE AFTERNOON AND
EVENING IS EXPECTED TO PERSIST TONIGHT AS THE LLJ IS IN EXCESS OF
40 TO 45 KTS. EVEN WITH THIS POTENTIAL FOR STRONG
STORMS...CONFIDENCE IS STILL NOT HIGH FOR WIDESPREAD
PRECIPITATION AS MODELS ARE NOT CONSISTENT WITH DEVELOPMENT/QPF.
WENT WITH SCATTERED POPS THROUGHOUT THE DAY AND WILL NEED TO MONITOR
THE TREND AS THE DAY PROGRESSES AND CONVECTION UNFOLDS.
TEMPERATURES TODAY ARE DEPENDENT ON CLOUD COVER. GENERALLY WE
SHOULD SEE HIGH TEMPS A FEW DEGREES WARMER THAN YESTERDAY DUE TO
THE INCREASED MIDLEVEL TEMPS. REMAINING CLOUD COVER IN THE MORNING
AND CONVECTION IN THE AFTERNOON MIGHT REDUCE DAYTIME HEATING...BUT
BREAKS IN CLOUD COVER COULD ALLOW TEMPERATURES TO APPROACH THE LOW
90S...ESPECIALLY IN THE SOUTHWEST PART OF THE CWA.
LOWS TONIGHT ARE EXPECTED TO BE IN THE MID TO UPPER 60S IN THE
WARMER AIR MASS. THESE LOW TEMPS ARE NEAR AVERAGE FOR THIS TIME OF
YEAR.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 346 AM CDT THU AUG 1 2013
FRIDAY MORNING THROUGH WEDNESDAY. CONCERN CONTINUES TO
REVOLVE AROUND PERIODIC CHANCES FOR RAIN DURING THE ENTIRE EXTENDED
PERIOD.
STARTING OUT FRIDAY MORNING IN THE UPPER LEVELS...MODELS STILL
CONSISTENT IN SHOWING ONE CLOSED LOW OVER THE PACIFIC NORTHWEST AND
ANOTHER ONE OVER NORTHERN ONTARIO. THESE CONTINUE TO DAMPEN THE HIGH
OVER THE SOUTHERN PLAINS. IMPRESSIVE NORTHERN STREAM FOR THIS TIME
OF YEAR WHICH WILL AFFECT THE NORTHERN HALF OF THE CONUS. AT THE
SURFACE...EXPECT LOW PRESSURE OVER SOUTHWEST NEBRASKA WITH A WARM
FRONT EXTENDING SOMEWHERE ACROSS THE CWA. BELIEVE ANY OVERNIGHT
CONVECTION SHOULD HAVE WORKED ITS WAY EAST OF THE CWA BY 12Z FRIDAY
AND WILL TAKE OUT LOW POPS THAT WERE PREVIOUSLY IN THE EASTERN PART
OF OUR AREA. WILL ALSO LEAVE ANY RAIN CHANCES OUT DURING THE DAYTIME
ON FRIDAY AS MOST OF THE CONVECTION THE PAST FEW WEEKS HAS OCCURRED
DURING THE EVENING AND OVERNIGHT TIME FRAME. SHOULD STILL BE IN THE
WARM SECTOR FOR MOST OF THE AREA ON FRIDAY BUT BY SATURDAY THE
SURFACE LOW PUSHES SOUTH AND OUR WINDS BECOME MORE NORTHEASTERLY
WITH SOME COOLER AIR PUSHING IN. HIGHS ON SAT SHOULD BE ABOUT 5
DEGREES BELOW THOSE ON FRIDAY.
AS HAS BEEN NOTED IN PREVIOUS AFDS...TOUGH TO TIME ANY SHORTWAVE
TROUGHS MOVING OVER THE AREA MORE THAN A DAY OR TWO OUT. HOWEVER
BOTH THE LATEST GFS AND EC OPERATIONAL RUNS SIMILAR IN SLIDING ONE
OF THESE WAVES THROUGH THE RIDGE AND OVER US SATURDAY NIGHT. FOR
THIS REASON WILL UP RAIN CHANCES SAT NIGHT AND CONTINUE INTO SUNDAY.
AFTER THAT WE CONTINUE WITH NORTHWEST FLOW AS THE BIG PICTURE POINTS
TO TROUGHING IN THE EAST AND WEST CONUS WITH WEAK RIDGING IN THE
CENTRAL THROUGH AT LEAST THE MIDDLE PART OF NEXT WEEK. THESE LEAVES
US OPEN TO ADDITIONAL DISTURBANCES MOVING THROUGH SO WILL CONTINUE
WITH 20-30 POPS.
IN REGARDS TO SEVERE...DEEP LAYER SHEAR LOOKS FAVORABLE AT LEAST
THROUGH THE WEEKEND WITH 0-6 KM BULK SHEAR PROGGED FROM 25 KT IN
THE SOUTHERN CWA TO 40 KT IN THE NORTH. INSTABILITY ALSO LOOKS OK.
ONE ISSUE THIS TIME OF YEAR IS WILL THERE BE ANY CAPPING TAKING
PLACE. MODELS DO HINT AT THAT AND WILL BE SOMETHING TO WATCH.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 528 AM CDT THU AUG 1 2013
CONVECTION CONTINUES TO DEVELOP EARLY THIS MORNING ACROSS PORTIONS
OF WESTERN AND NORTHERN NEBRASKA. THE ACTIVITY IS ISOLATED
ATTM...WITH COVERAGE EXPECTED TO INCREASE TODAY. SCATTERED TSTMS
WILL PERSIST DURING THE DAY WITH HIT OR MISS CHCS FOR THE TERMINAL
ITSELF AND HAVE CARRIED A VCTS WITH THE BETTER CHCS FROM MID DAY
ON. SEVERE STORMS ARE POSSIBLE MAINLY THIS AFTN INTO TONIGHT WITH
LARGE HAIL AND DAMAGING WINDS THE PRIMARY HAZARDS. TSTMS SHOULD
MOVE SOUTH OF THE TERMINAL BY DAYBREAK FRIDAY. LOOK FOR LIGHT AND
VARIABLE WINDS THIS MORNING TO TRANSITION SOUTHERLY AS A SFC RIDGE
SHIFTS EAST AND LOW PRESSURE DEEPENS ALONG THE HIGH PLAINS.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...MANGELS/FAY
LONG TERM...EWALD
AVIATION...FAY
AREA FORECAST DISCUSSION
NWS HASTINGS NE
354 AM CDT THU AUG 1 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 346 AM CDT THU AUG 1 2013
IN THE UPPER LEVELS WE ARE STILL IN GENERALLY NORTHWESTERLY FLOW
WITH A RIDGE LOCATED TO THE WEST CENTERED OVER THE ROCKIES. AT THE
SURFACE WE HAVE HIGH PRESSURE SLIGHTLY TO OUR NORTHEAST WITH A GOOD
TONGUE OF MOISTURE REACHING UP THROUGH THE CENTRAL PLAINS. THIS
MOISTURE IS ALSO APPARENT AT 850HPA WITH DEWPOINTS NEAR 15 DEGREES.
CURRENT KUEX RADAR SHOWS A FEW THUNDERSTORMS ENTERING THE NORTHWEST
PORTION OF OUR CWA. THE RAP MODEL...AND TO SOME DEGREE THE WRF
MODELS...SEEMED TO HAVE THE BEST HANDLE FOR THIS TIME PERIOD WHICH
MAINTAINS CHANCES OF PRECIPITATION FOR THE WESTERN PART OF OUR CWA
INTO THE MORNING.
MAIN CONCERN FOR THIS FORECAST IS CONVECTION AND SEVERE WEATHER
POTENTIAL FOR TODAY. THE SURFACE HIGH WILL MOVE OFF TO THE EAST
AS A LOW DEVELOPS TO THE WEST. AS THE HIGH MOVES OFF...INCREASINGLY
SOUTHERLY FLOW WILL BRING IN MORE MOISTURE WITH AFTERNOON DEW
POINTS IN THE MID TO UPPER 60S. A WARM FRONT WILL LIFT NORTH
ACROSS NEBRASKA REACHING CENTRAL NEBRASKA THIS AFTERNOON. MODELS
ARE INDICATING INSTABILITY INCREASING TO 2000 TO 3000 J/KG ALONG
WITH DEEP LAYER SHEAR OF 40 TO 50 KTS. THESE PARAMETERS ARE
SUFFICIENT FOR SUPERCELL DEVELOPMENT ESPECIALLY IN THE VICINITY OF
THE WARM FRONT. STORMS WHICH DEVELOP WILL BE CAPABLE OF PRODUCING
VERY LARGE HAIL...STRONG WINDS...AND EVEN TORNADOES NEAR THE
BOUNDARY. PRECIPITABLE WATERS THIS AFTERNOON AVERAGE 1.50 INCHES AND ARE
130 PERCENT OF NORMAL. LOCALLY HEAVY RAINFALL IN EXCESS OF AN INCH
OR TWO IS POSSIBLE. CONVECTION THAT DEVELOPS IN THE AFTERNOON AND
EVENING IS EXPECTED TO PERSIST TONIGHT AS THE LLJ IS IN EXCESS OF
40 TO 45 KTS. EVEN WITH THIS POTENTIAL FOR STRONG
STORMS...CONFIDENCE IS STILL NOT HIGH FOR WIDESPREAD
PRECIPITATION AS MODELS ARE NOT CONSISTENT WITH DEVELOPMENT/QPF.
WENT WITH SCATTERED POPS THROUGHOUT THE DAY AND WILL NEED TO MONITOR
THE TREND AS THE DAY PROGRESSES AND CONVECTION UNFOLDS.
TEMPERATURES TODAY ARE DEPENDENT ON CLOUD COVER. GENERALLY WE
SHOULD SEE HIGH TEMPS A FEW DEGREES WARMER THAN YESTERDAY DUE TO
THE INCREASED MIDLEVEL TEMPS. REMAINING CLOUD COVER IN THE MORNING
AND CONVECTION IN THE AFTERNOON MIGHT REDUCE DAYTIME HEATING...BUT
BREAKS IN CLOUD COVER COULD ALLOW TEMPERATURES TO APPROACH THE LOW
90S...ESPECIALLY IN THE SOUTHWEST PART OF THE CWA.
LOWS TONIGHT ARE EXPECTED TO BE IN THE MID TO UPPER 60S IN THE
WARMER AIR MASS. THESE LOW TEMPS ARE NEAR AVERAGE FOR THIS TIME OF
YEAR.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 346 AM CDT THU AUG 1 2013
FRIDAY MORNING THROUGH WEDNESDAY. CONCERN CONTINUES TO
REVOLVE AROUND PERIODIC CHANCES FOR RAIN DURING THE ENTIRE EXTENDED
PERIOD.
STARTING OUT FRIDAY MORNING IN THE UPPER LEVELS...MODELS STILL
CONSISTENT IN SHOWING ONE CLOSED LOW OVER THE PACIFIC NORTHWEST AND
ANOTHER ONE OVER NORTHERN ONTARIO. THESE CONTINUE TO DAMPEN THE HIGH
OVER THE SOUTHERN PLAINS. IMPRESSIVE NORTHERN STREAM FOR THIS TIME
OF YEAR WHICH WILL AFFECT THE NORTHERN HALF OF THE CONUS. AT THE
SURFACE...EXPECT LOW PRESSURE OVER SOUTHWEST NEBRASKA WITH A WARM
FRONT EXTENDING SOMEWHERE ACROSS THE CWA. BELIEVE ANY OVERNIGHT
CONVECTION SHOULD HAVE WORKED ITS WAY EAST OF THE CWA BY 12Z FRIDAY
AND WILL TAKE OUT LOW POPS THAT WERE PREVIOUSLY IN THE EASTERN PART
OF OUR AREA. WILL ALSO LEAVE ANY RAIN CHANCES OUT DURING THE DAYTIME
ON FRIDAY AS MOST OF THE CONVECTION THE PAST FEW WEEKS HAS OCCURRED
DURING THE EVENING AND OVERNIGHT TIME FRAME. SHOULD STILL BE IN THE
WARM SECTOR FOR MOST OF THE AREA ON FRIDAY BUT BY SATURDAY THE
SURFACE LOW PUSHES SOUTH AND OUR WINDS BECOME MORE NORTHEASTERLY
WITH SOME COOLER AIR PUSHING IN. HIGHS ON SAT SHOULD BE ABOUT 5
DEGREES BELOW THOSE ON FRIDAY.
AS HAS BEEN NOTED IN PREVIOUS AFDS...TOUGH TO TIME ANY SHORTWAVE
TROUGHS MOVING OVER THE AREA MORE THAN A DAY OR TWO OUT. HOWEVER
BOTH THE LATEST GFS AND EC OPERATIONAL RUNS SIMILAR IN SLIDING ONE
OF THESE WAVES THROUGH THE RIDGE AND OVER US SATURDAY NIGHT. FOR
THIS REASON WILL UP RAIN CHANCES SAT NIGHT AND CONTINUE INTO SUNDAY.
AFTER THAT WE CONTINUE WITH NORTHWEST FLOW AS THE BIG PICTURE POINTS
TO TROUGHING IN THE EAST AND WEST CONUS WITH WEAK RIDGING IN THE
CENTRAL THROUGH AT LEAST THE MIDDLE PART OF NEXT WEEK. THESE LEAVES
US OPEN TO ADDITIONAL DISTURBANCES MOVING THROUGH SO WILL CONTINUE
WITH 20-30 POPS.
IN REGARDS TO SEVERE...DEEP LAYER SHEAR LOOKS FAVORABLE AT LEAST
THROUGH THE WEEKEND WITH 0-6 KM BULK SHEAR PROGGED FROM 25 KT IN
THE SOUTHERN CWA TO 40 KT IN THE NORTH. INSTABILITY ALSO LOOKS OK.
ONE ISSUE THIS TIME OF YEAR IS WILL THERE BE ANY CAPPING TAKING
PLACE. MODELS DO HINT AT THAT AND WILL BE SOMETHING TO WATCH.
&&
.AVIATION...FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1203 AM CDT THU AUG 1 2013
VFR CONDITIONS ARE EXPECTED THROUGH THE TAF PERIOD. WINDS WILL BE
LIGHT AND VARIABLE THROUGH THE NIGHT BEFORE TRANSITIONING
SOUTHERLY AS SFC RIDGE OVER EASTERN NEBRASKA SHIFTS EAST. MAIN
CONCERN IS TIMING OF POTENTIAL CONVECTION FOR KGRI. IF STORMS
ACROSS WESTERN NEB HOLD TOGETHER...THEY MAY REACH THE TERMINAL
AFTER DAYBREAK THURSDAY. MODELS SUGGEST BETTER TIMING FOR
CONVECTION DURING THE AFTN/EVENING HOURS AND HAVE INCLUDED VCTS
FOR NOW.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...MANGELS/FAY
LONG TERM...EWALD
AVIATION...FAY/MANGELS
AREA FORECAST DISCUSSION
NWS ELKO NV
211 AM PDT THU AUG 1 2013
.SYNOPSIS...A LOW PRESSURE SYSTEM WILL BRUSH THE SILVER STATE
TODAY BRINGING GUSTY WINDS...ALONG WITH A FEW THUNDERSTORMS ACROSS
NORTHERN NEVADA. HIGH TEMPERATURES WILL DIP INTO THE 80S TODAY AND
FRIDAY THEN WARM UP A BIT THIS WEEKEND AS HIGH PRESSURE SPREADS
BACK OVER THE GREAT BASIN.
&&
.SHORT TERM...TODAY THROUGH FRIDAY. THUNDERSTORM ACTIVITY
DISSIPATED OVER THE JACKPOT AREA OF NORTHERN NEVADA AROUND 06Z AS
PLANNED. MOUNTAIN SHOWERS ALONG WITH A LIGHTNING STRIKE EVERY NOW
AND THEN HAVE BEEN OCCURRING OVER NORTHERN HUMBOLDT COUNTY THIS
MORNING...FUELED BY A JET CORE ALOFT. THE MODELS ARE IN EXCELLENT
AGREEMENT THROUGH FRIDAY. AN UPPER LOW PRESSURE SYSTEM WILL BE
MOVING ONSHORE ACROSS OREGON TODAY...COINCIDING WITH THE PASSAGE
THROUGH THE GREAT BASIN OF THE STRONGEST SHORTWAVE EMANATING FROM
THE PARENT LOW FEATURE THIS AFTERNOON.
THIS MORNING. THE RIGHT REAR QUAD OF A 100 KT 250 MB JET CORE IS
CROSSING HUMBOLDT COUNTY AT THIS TIME. ADDED ISOLATED
THUNDERSTORMS...DRY BELOW 6000 FT TO HUMBOLDT COUNTY FOR THE
MORNING HOURS.
THIS AFTERNOON THROUGH THIS EVENING. THE STRONGEST SHORTWAVE LOBE
WILL PUSH INLAND OVER OREGON AND A 60-70 KT H4 JET CORE WILL BE
CROSSING WEST TO EAST ACROSS THE STATE. THE RR QUAD SHOULD ENSURE
SOME HEFTY WIND GUSTS MIX DOWN TO THE SURFACE OVER MOST OF THE LKN
CWFA....MAINLY A FIRE WEATHER CONCERN. HIGH TEMPERATURES WILL
RANGE FROM THE MID 80S TO AROUND 90 DEGREES.
TONIGHT THROUGH FRIDAY. A DRIER AND COOLER AIR MASS WILL BE
MOVING INTO THE REGION. AS THE UPPER LOW BEGINS TO PULL TO THE
NORTHEAST...CROSSING WASHINGTON STATE...A WEAKENING LOW LEVEL JET
CORE WILL LINGER LONG ENOUGH TO PRODUCE ANOTHER DAY OF BREEZY
WINDS. SURFACE GUSTS WILL BE LESS INTENSE WITH LESS COVERAGE THAN
THIS AFTERNOON...AND MORE PREVALENT OVER EAST CENTRAL NEVADA. LOW
TEMPERATURES WILL GENERALLY RANGE FROM THE MID 40S TO THE MID 50S.
HIGH TEMPERATURES WILL BE IN THE 80S.
.LONG TERM...FRIDAY NIGHT THROUGH NEXT WEDNESDAY. MODELS IN GOOD
AGREEMENT THROUGH SUNDAY. SOUTHWESTERLY FLOW WILL CONTINUE OVER THE
CWA THROUGH THE UPCOMING WEEKEND WITH BREEZY CONDITIONS ACROSS
CENTRAL NEVADA WITH A LOW PRESSURE SYSTEM OVER THE PACIFIC NORTHWEST
AND HIGH PRESSURE OVER NEW MEXICO. NEXT MONDAY THE RIDGE BUILDS WITH
RISING HEIGHTS OVER THE GREAT BASIN AND SLIGHTLY WARMER
TEMPERATURES. THIS BUILDING RIDGE WILL BRING SOUTHERLY FLOW AND
MOISTURE WILL BEGIN TO RETURN TO PORTIONS OF CENTRAL AND EASTERN
NEVADA EARLY NEXT WEEK...HOWEVER MODELS DIFFER ON HOW MUCH MOISTURE
AND INSTABILITY. THUS HAVE LOW POPS ESPECIALLY OVER MOUNTAINS EARLY
NEXT WEEK. TEMPERATURES WILL BE NEAR NORMAL INCREASING TO SLIGHTLY
ABOVE NORMAL BY EARLY NEXT WEEK.
&&
.AVIATION...VFR CONDITIONS OVER THE NEXT 24HRS. WINDS WILL BE GUSTY
THIS AFTERNOON DECREASING AFTER SUNSET.
&&
.FIRE WEATHER...AN UPPER LEVEL TROUGH WILL MOVE THROUGH THE PACIFIC
NORTHWEST...RESULTING IN GUSTY SURFACE WINDS TODAY AND TO A LESSER
EXTEND ON FRIDAY.
TODAY...DRY THUNDERSTORM COVERAGE WILL BE MINIMAL AND MAINLY AFFECT
NORTHERN FIRE ZONES THROUGH THE EVENING. WIND GUSTS ABOVE 30 MPH
WILL BE MORE WIDESPREAD THAN WEDNESDAY AND WILL BE PROBLEMATIC
WHEN COMBINED WITH MINIMUM RELATIVE HUMIDITY VALUES SOLIDLY BELOW
15%. A RED FLAG WARNING IS IN EFFECT FOR ALL FIRE ZONES EXCEPT
FIRE ZONE 454. WIND SPEEDS...ESPECIALLY IN THE VALLEY
LOCALES...ARE EXPECTED TO BE JUST BELOW CRITERIA IN ZONE
454...ALTHOUGH MID- SLOPES AND HIGHER ELEVATION SITES COULD SEE
HIGHER WINDS.
BREEZY WINDS ARE FORECAST ON FRIDAY AS WELL...HOWEVER GUSTS ARE
EXPECTED TO GENERALLY BE BELOW 30 MPH. THE STRONGEST WINDS FRIDAY
WILL BE OVER ZONE 455 AND EASTERN ZONE 457.
HIGH PRESSURE WILL BEGIN TO BUILD OVER THE REGION. WARMER AND
DRIER CONDITIONS ARE EXPECTED.
&&
.LKN WATCHES/WARNINGS/ADVISORIES...
RED FLAG WARNING FROM 11 AM THIS MORNING TO 8 PM PDT THIS
EVENING FOR HUMBOLDT COUNTY...NORTHERN ELKO COUNTY...NORTHERN
LANDER COUNTY AND NORTHERN EUREKA COUNTY...RUBY MOUNTAINS/EAST
HUMBOLDT RANGE...SOUTH CENTRAL ELKO COUNTY...SOUTHEASTERN ELKO
COUNTY...SOUTHWESTERN ELKO COUNTY...WHITE PINE COUNTY.
RED FLAG WARNING UNTIL 8 PM PDT THIS EVENING FOR NORTHEASTERN
NYE COUNTY...NORTHWESTERN NYE COUNTY...SOUTHERN LANDER COUNTY
AND SOUTHERN EUREKA COUNTY.
&&
$$
92/87/87/92
AREA FORECAST DISCUSSION
NWS BUFFALO NY
145 AM EDT THU AUG 1 2013
.SYNOPSIS...
SHOWERS AND SCATTERED THUNDERSTORMS WILL OVERSPREAD THE REGION VERY
LATE TONIGHT AND THURSDAY AS A COLD FRONT APPROACHES THEN CROSSES
THE REGION. LINGERING MOISTURE AND SOMEWHAT UNSTABLE AIR BEHIND THE
FRONT MAY BRING A FEW MORE WIDELY SCATTERED SHOWERS ON FRIDAY. BELOW
AVERAGE TEMPERATURES WILL LAST THROUGH THE WEEKEND AND INTO AT LEAST
EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH TODAY/...
THE LATEST SURFACE MAP SHOWS LOW PRESSURE CENTERED JUST NORTH OF
LAKE ERIE WITH A WEAK TROUGH/COLD FRONT TRAILING SOUTH ACROSS
WESTERN OHIO/EASTERN INDIANA. REGIONAL RADARS STILL SHOW AN AREA OF
STEADY SHOWERS IN THE VICINITY OF THE LOW...STRETCHING NORTH TOWARD
GEORGIAN BAY AND WESTERN LAKE ONTARIO. RADAR TRENDS AND SHORT TERM
MESOSCALE MODEL GUIDANCE SUCH AS THE HRRR AND THE 00Z NAM SUGGESTS
THAT THE BULK OF THESE SHOWERS WILL STAY TO OUR WEST FOR MUCH OF THE
NIGHT UNTIL AN UPSTREAM SHORT WAVE OVER MICHIGAN PUSHES THE PCPN
INTO WESTERN NEW YORK BY DAYBREAK. SURFACE OBSERVATIONS AND REGIONAL
LIGHTNING PLOTS ALSO SHOW A FAIR AMOUNT OF ELEVATED CONVECTION
EMBEDDED WITHIN THE GENERAL AREA OF SHOWERS.
AS THE MID LEVEL SHORT WAVE AND ASSOCIATED SURFACE LOW TRACK JUST
NORTH OF LAKE ONTARIO LATER THIS MORNING...THE TRAILING COLD FRONT
WILL INTERACT WITH ABUNDANT LOW LEVEL MOISTURE THAT WILL BE
ADVECTING NORTH FROM THE OHIO VALLEY. AT THE SAME TIME...AN UPPER
LEVEL JET WILL STRENGTHEN ACROSS SOUTHERN QUEBEC...WITH THE FAVORED
RIGHT ENTRANCE REGION AND ASSOCIATED UPPER LEVEL DIVERGENCE PLACED
OVER THE LOWER LAKES. THE MOISTURE AND LARGE SCALE LIFT WILL KEEP
THE AREA OF SHOWERS AND SCATTERED THUNDERSTORMS INTACT.
EXPECT MOST OF THE RAIN TO FALL IN A 3-5 HOUR WINDOW JUST BEFORE
DAYBREAK THROUGH THIS MORNING IN THE WEST...AND HOUR OR TWO LATER IN
THE GENESEE VALLEY...AND FROM MID MORNING THROUGH MID AFTERNOON
THURSDAY ACROSS THE NORTH COUNTRY AND CENTRAL NY. MODEST INSTABILITY
WILL SUPPORT A FEW EMBEDDED THUNDERSTORMS. EXPECT BASIN AVERAGE
RAINFALL TOTALS TO RANGE FROM A QUARTER TO THIRD OF AN INCH IN MOST
LOCATIONS... ALTHOUGH ANY EMBEDDED CONVECTION WILL PRODUCE LOCALLY
HIGHER AMOUNTS.
FOLLOWING THE END OF THE SHOWERS LATER THIS MORNING IN THE
WEST...EXPECT A FEW BREAKS OF SUNSHINE ALTHOUGH LINGERING LOW LEVEL
MOISTURE AND COOLING TEMPS ALOFT WILL LIKELY PRODUCE PLENTY OF
CUMULUS DURING THE AFTERNOON.
&&
.SHORT TERM /TONIGHT THROUGH SATURDAY NIGHT/...
THURSDAY NIGHT A COLD FRONT WILL CONTINUE TO SLICE ACROSS THE
REMAINDER OF THE CWA...WITH A NARROW LINE OF SHOWERS LIKELY ALONG
THE IMMEDIATE FRONTAL BOUNDARY. THE DEEPEST MOISTURE WILL RUN OUT
AHEAD OF THE COLD FRONT...LEAVING A MORE STABLE ATMOSPHERE FOR THE
COLD FRONT TO SHIFT ACROSS...WITH SHOWERS LIKELY BUT NO THUNDER.
TEMPERATURES THURSDAY NIGHT WILL DROP BACK INTO THE 50S...WITH A
SPOT 40S NOT OUT OF THE QUESTION ACROSS THE VALLEYS OF THE INTERIOR
SOUTHERN TIER.
FOR FRIDAY AND INTO SATURDAY A -1SD UPPER LEVEL TROUGH WILL BE
ANCHORED ACROSS THE NORTHEAST AND SOUTHERN CANADA. MULTIPLE
SHORTWAVES WILL RIDE THROUGH THIS TROUGH SPARKING SHOWERS ON BOTH
FRIDAY AND SATURDAY. WILL COVER THIS WITH A BROAD BRUSH CHANCE POP
THROUGH THE TIME PERIOD...WITH GREATEST CHANCES DURING THE AFTERNOON
AND EARLY EVENING WHEN DAYTIME INSTABILITY SHOWERS WILL BE GREAT
CHANCES FOR OCCURRENCE.
ALSO OF NOTE FOR BOTH FRIDAY MORNING AND SATURDAY MORNING WILL BE A
MARGINAL SETUP FOR LAKE EFFECT RAIN. TEMPERATURES ALOFT BOTH
MORNINGS WILL DROP TO ABOUT +9 TO +10...WHICH WILL JUST TOUCH THE
DELTA 13C FROM 850 HPA DOWN TO THE SURFACE...WITH LIMITED LAKE
INSTABILITY. A LAKE EFFECT RAIN SHOWER IS POSSIBLE BOTH MORNINGS.
TEMPERATURES BOTH DAYS WILL AVERAGE JUST BELOW NORMAL WITH HIGHS IN
THE LOW TO MID 70S...AND NIGHTTIME LOWS DROPPING BACK INTO THE
50S...WITH AROUND 60 ALONG THE LAKESHORE PLAINS.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
TEMPERATURES ARE EXPECTED TO REMAIN BELOW NORMAL THROUGH THIS TIME
PERIOD...WITH AN AMPLIFIED PATTERN CONSISTING OF A RIDGE ACROSS THE
WEST AND TROUGH ACROSS THE EAST. VARIOUS SHORTWAVES RIDING THROUGH
THIS TROUGH WILL BRING CHANCES OF PRECIPITATION.
ON SUNDAY MODEL CONSENSUS IS NOW TO BRING A SHORTWAVE TROUGH
DROPPING FROM NEAR THE NORTHERN GREAT LAKES AND ACROSS OUR REGION.
THE CORE OF THE SHORTWAVE...MINUS 2 SD AT 500 HPA ACCORDING TO THE
06Z/31 GEFS WILL RIDE ACROSS THE NORTH COUNTRY. WITH ANOTHER SHOT OF
COLD AIR WITH THIS SHORT WAVE...AROUND 6 TO 7C AT 850 HPA...CREATING
STEEP LOW LEVEL LAPSE RATES...COMBINED WITH THE PASSAGE OF THE
SHORTWAVE A CHANCE OF SHOWERS WILL BE POSSIBLE SUNDAY. WILL HAVE THE
GREATEST CHANCE ACROSS LAKE ONTARIO AND THE NORTH COUNTRY WHERE THE
STEEPER LAPSE RATES AND GREATER HEIGHT FALLS WILL BE FOUND.
THE COOL POOL OF AIR ALOFT WILL ALSO CREATE A MOSTLY CLOUDY DAY WITH
COOL AFTERNOON TEMPERATURES. WITH NOT MUCH SUNSHINE SUNDAY HIGHS
WILL ONLY CLIMB INTO THE UPPER 60S TO LOWER 70S ACROSS THE REGION.
HIGH PRESSURE WILL START TO BUILD INTO THE REGION SUNDAY NIGHT AND
PUSH DRIER AIR ACROSS THE REGION. THIS DRIER AIR COUPLED WITH THE
LOSS OF DAYTIME HEATING AND THE SUBSIDENCE BEHIND THE SHORTWAVE WILL
BRING AN END TO THE SHOWERS AND ALLOW FOR SOME CLEARING
SKIES....ESPECIALLY ACROSS WNY. WINDS WILL VEER TO NORTHWEST WHICH
WITH THE UPSLOPE FLOW MAY LINGER LOW CLOUDS ACROSS THE WNY...AND
THIS WILL MAKE FOR A LITTLE BIT OF UNCERTAINTY TO OVERNIGHT LOWS.
TOTAL CLEARING WILL ALLOW FOR A VERY CHILLY NIGHT WITH MANY AREAS
DROPPING DOWN INTO THE 40S...WITH ONLY AROUND 50 NEAR THE
LAKESHORES. FOR NOW LEAVE SOME LOW CLOUDS IN THE GRIDS OVERNIGHT AND
NOT GO QUITE AS COLD AS WHAT A COMPLETE CLEARING NIGHT WOULD GIVE
US. THE OTHER CONCERN FOR SUNDAY NIGHT WILL BE LAKE EFFECT CLOUDS
AND POSSIBLE LIGHT SHOWERS SOUTHEAST OF LAKE ONTARIO. WITH A CHILLY
8C 850 HPA AIR CROSSING THE LAKE SOME LAKE EFFECT CLOUDS AND PERHAPS
EVEN A LIGHT SHOWER IS POSSIBLE...THOUGH SYNOPTIC MOISTURE IS
LACKING AND WILL HOLD POPS SOUTHEAST OF LAKE ONTARIO TO LOW
CHANCE.
ON MONDAY SOME BACKING TO THE WINDS AS HIGH PRESSURE DROPS JUST TO
THE SOUTH OF THE REGION WILL ALLOW FOR CLEARING SKIES. CLOUDS WILL
BE MOST PLENTIFUL ACROSS THE NORTH COUNTRY CLOSER TO THE UPPER LEVEL
LOW...AND IN FACT THERE MAY EVEN STILL BE A SHOWER THIS DAY...SO
WILL HAVE A LOW CHANCE POP ACROSS THIS REGION.
HIGHS MONDAY WILL LIKELY BE A COUPLE DEGREES WARMER THAN SUNDAY WITH
THE ADDITIONAL SUNSHINE...AND NOT AS COOL TEMPERATURES ALOFT. HIGHS
WILL REACH BACK INTO THE 70S ACROSS THE REGION...COOLEST ACROSS THE
NORTH COUNTRY WHERE SOME CLOUDINESS MAY LINGER.
ANOTHER SHORTWAVE WILL RIDE ALONG THE WESTERN PERIPHERY OF THIS
UPPER LEVEL TROUGH AND DROP ACROSS THE GREAT LAKES REGION TUESDAY
AND WEDNESDAY. THIS WILL BRING ADDITIONAL CHANCES FOR SHOWERS...WITH
TEMPERATURES REMAINING COOL.
&&
.AVIATION /06Z THURSDAY THROUGH MONDAY/...
VFR CONDITIONS WILL PREVAIL FOR MOST OF THE EARLY MORNING HOURS AS
THE FIRST AREA OF RAIN OVER SOUTHERN ONTARIO WILL REMAIN TO THE
NORTH AND WEST OF THE AREA THROUGH AT LEAST 08Z-09Z. THIS WILL LEAVE
THICKENING AND LOWERING MID LEVEL CLOUDS SPREADING FROM WEST TO EAST
ACROSS THE AREA. EXPECT A 3-5 HOUR PERIOD OF SHOWERS TO CROSS THE
REGION FROM WEST TO EAST LATE TONIGHT THROUGH THE FIRST HALF OF
THURSDAY AS A COLD FRONT AND STRENGTHENING MID LEVEL TROUGH CROSS
THE AREA. THE HEAVIER SHOWERS MAY PRODUCE PERIODS OF MVFR CIGS/VSBY
AND POSSIBLY EVEN A BRIEF PERIOD OF IFR. BEHIND THE COLD FRONT
EXPECT RAIN TO TAPER OFF...ALTHOUGH MVFR CIGS MAY LINGER FOR A FEW
HOURS BEFORE IMPROVING TO VFR DURING THE AFTERNOON.
FARTHER EAST AT KART...EXPECT THE SAME TREND JUST A FEW HOURS
LATER...WITH THE BULK OF THE RAIN AND POTENTIAL FOR LOWER CIGS/VSBY
COMING FROM MID MORNING THROUGH MID AFTERNOON THURSDAY.
OUTLOOK...
FRIDAY AND SATURDAY...MAINLY VFR WITH A SMALL CHANCE OF SHOWERS.
SUNDAY AND MONDAY...VFR.
&&
.MARINE...
A RELATIVELY WEAK PRESSURE GRADIENT WILL REMAIN IN PLACE ACROSS THE
LOWER LAKES TONIGHT. AFTER A FRONT CROSSES THE LAKES ON
THURSDAY...THE WINDS WILL SWITCH TO THE SOUTHWEST AND PICK UP A
BIT...BUT CONDITIONS ARE EXPECTED TO REMAIN BELOW SMALL CRAFT
ADVISORY CRITERIA. MORE IMPORTANTLY...THE FRONT WILL BRING A GOOD
CHANCE FOR SHOWERS AND POSSIBLE THUNDERSTORMS LATE TONIGHT AND
THURSDAY...WITH LOCAL INCREASES IN WIND AND WAVES POSSIBLE.
THE PRESSURE GRADIENT BETWEEN BETWEEN A SURFACE HIGH OVER THE MIDDLE
ATLANTIC STATES AND LOW PRESSURE PUSHING ACROSS HUDSON BAY WILL
CAUSE WESTERLY WINDS TO PICK UP A LITTLE MORE ON FRIDAY. WATERSPOUTS
WILL BECOME POSSIBLE AGAIN AT TIMES FRIDAY INTO THE WEEKEND AS TEMPS
COOL ALOFT.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...LEVAN
NEAR TERM...HITCHCOCK/TJP
SHORT TERM...THOMAS
LONG TERM...THOMAS
AVIATION...HITCHCOCK/TJP
MARINE...HITCHCOCK/LEVAN
AREA FORECAST DISCUSSION
NWS RALEIGH NC
1007 PM EDT FRI AUG 2 2013
.SYNOPSIS...
A WEAK COLD FRONT OVER SOUTHERN AND EASTERN NC WILL GRADUALLY WASH
OUT THROUGH SATURDAY. ANOTHER STRONGER COLD FRONT WILL CROSS OUR
REGION ON SUNDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 10 PM FRIDAY...
A WEAKENING SURFACE BOUNDARY LOCATED ACROSS SOUTH/SOUTHEASTERN
PORTIONS OF THE AREA COMBINED WITH STILL SUFFICIENT INSTABILITY LATE
THIS EVENING ARE SUPPORTING SHOWER AND THUNDERSTORM DEVELOPMENT
OVER PORTIONS OF THE SANDHILLS AND SOUTHERN COASTAL PLAIN. THE SPC
MESO PAGE IS STILL SHOWING UPWARDS OF 2000 J/KG OF MLCAPE... WITH A
SLOWLY STABILIZING BOUNDARY LAYER. THE LATEST HRRR AND OTHER HI-RES
MODELS SHOW THIS ACTIVITY GRADUALLY WEAKENING THIS LATE THIS INTO
THE EARLY MORNING HOURS OF SATURDAY. THIS SEEMS REASONABLE.
HOWEVER... A WEAK IMPULSE OR TWO MOVING THROUGH THE WEST TO
WEST-NORTHWEST MID LEVEL FLOW COULD HELP A FEW ISOLATED SHOWERS
DEVELOP EVEN AFTER 06Z INVOF THE WEAK FRONT. WILL SHOW A GOOD CHANCE
FOR SHOWERS AND STORMS THROUGH 06Z ACROSS THE AREA MENTION ABOVE
(SE)... TRANSITING TO A SLIGHT CHANCE OF STORMS AFTER 06Z (WILL ADD
TO NEXT UPDATE TO FORECAST AROUND 1130-12)... WITH A DRY FORECAST
ELSEWHERE. DO NOT EXPECT ANY SVR WEATHER FROM THESE SHOWERS AND
STORMS... BUT LOCALIZED FLOODING MAY BE POSSIBLE... ESPECIALLY
ACROSS PORTIONS OF CUMBERLAND AND NORTHERN SAMPSON COUNTIES (WHERE
MODERATE TO HEAVY RAIN HAS BEEN FALLING FOR SEVERAL HOURS). EXPECT
SKIES WILL AT LEAST BE PARTLY TO MOSTLY CLOUDY OVERNIGHT... WITH AT
LEAST SOME MID/HIGH LEVEL DEBRIS CLOUDINESS FROM CONVECTION
UPSTREAM. IN ADDITION... THINK WE CLOUD SEE SOME LOW STRATUS AND OR
FOG... ESPECIALLY INVOF THE WEAK BOUNDARY. GIVEN THIS HAVE BUMPED UP
LOW TEMPS BY A COUPLE OF DEGREES INTO THE UPPER 60S NW TO LOWER 70S
SE.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 245 PM FRIDAY...
SATURDAY...
THE WEAK FRONTAL ZONE OVER SOUTHERN AND EASTERN NC WILL WASH OUT BY
SATURDAY AND SOUTHERLY SURFACE FLOW WILL PREVAIL ACROSS A GOOD
PORTION OF CENTRAL NC. THIS WILL ALLOW 70 DEGREE DEWPOINTS AND
BETTER INSTABILITY TO CREEP BACK TO THE NORTH...ALTHOUGH
NORTHWESTERLY FLOW AND STRONGER MIXING SHOULD SUPPRESS INSTABILITY
SOMEWHAT OVER THE NORTHWEST AND NORTHERN PIEDMONT. MODELS SHOW A
THERMALLY ENHANCE LEE TROUGH DURING THE AFTERNOON...THOUGH WITH ONLY
WEAK MASS CONVERGENCE AND SUBTLE RIPPLES IN THE PREVAILING NORTHWEST
FLOW ALOFT. THUS...SHOWERS AND STORMS YOU BE MOSTLY ISOLATED
OUTSIDE OF THE SEABREEZE OR STORMS MOVING OFF THE HIGHER TERRAIN.
SATURDAY NIGHT...
A STRONG SHORTWAVE MOVING THROUGH THE LONGWAVE TROUGH WILL PUSH A
MODEST COLD FRONT TOWARD OUR AREA LATE SATURDAY AND SUNDAY.
HOWEVER...WESTERLY DEEP LAYER FLOW AHEAD OF THE FRONT SHOULD
LIMIT MOISTURE AVAILABILITY...AND UNLESS MORE ORGANIZED CONVECTION
OVER THE MID-ATLANTIC STATES SENDS OUTFLOW SOUTH THROUGH VA...MOST
OF SATURDAY NIGHT APPEARS TO BE DRY. WILL INDICATE BETTER CLOUD
COVER ACROSS THE NORTH...WITH LOWS IN THE UPPER 60S AND LOWER 70S.
-BLS
SUNDAY AND SUNDAY NIGHT...
STRONG SHORTWAVE TROUGH OVER ONTARIO WILL DIVE SOUTHEAST THROUGH THE
EASTERN GREAT LAKES AND AND SOUTHERN NEW ENGLAND STATES ON
SUNDAY...REINFORCING THE EASTERN US TROUGH AND PAVING THE WAY FOR
YET ANOTHER WELL DEFINED SYNOPTIC SURFACE COLD FRONT INTO PARTS OF
THE SOUTHEAST STATES SUNDAY-SUNDAY NIGHT. OVER THE PAST 24
HOURS...NWP MODELS HAVE REALLY HONED IN WITH THE TIMING OF THE FRONT
THROUGH THE AREA BETWEEN 12 TO 18Z SUNDAY. MODELS HAVE ALSO TRENDED
DRIER WITH THE PASSAGE OF THE FRONT THROUGH THE CAROLINAS...OWING TO
THE EARLIER/UNFAVORABLE DIURNAL TIMING...WEAKENING-NEARLY NEGLIGIBLE
S/W DYNAMICS AT MORE SOUTHERN LATITUDES AS CORE OF DPVA AND H5 FALLS
SLIDE OFF THE NORTHERN MID-ATLANTIC SEABOARD...AND LASTLY THE LACK
OF DEEP MOISTURE TRANSPORT INTO THE AREA...ROBBED/DISRUPTED BY THE
SUBDUING EFFECTS OF THE DEEP WEST-NORTHWESTERLY FLOW IN PLACE EAST
OF THE MOUNTAINS.
AS SUCH...EXPECT TO SEE DIMINISHING RADAR TRENDS ACROSS CENTRAL NC
WITH LITTLE MORE THAN ISOLATED TO WIDELY SCATTERED SHOWERS
POSSIBLE...WITH BEST CHANCE ACROSS THE SOUTH DURING THE AFTERNOON
BEFORE THE FRONT SETTLES SOUTH OF THE AREA SUNDAY EVENING. IN THE
CASE THAT SOME MORE ORGANIZED CONVECTION DEVELOPS...MODERATELY
STRONG WESTERLIES IN THE MID LEVELS OF 40 TO 45KTS COULD SUPPORT AN
ISOLATED STRONG TO SEVERE STORM.
HIGHS IN THE MID 80S NORTH TO AROUND 90 SOUTH. THE NORTH-SOUTH
LOW-LEVEL COOL DRY AIR ADVECTION SUNDAY NIGHT SHOULD RESULT IN A
LARGER TEMPERATURE SPREAD THAN NORMAL FOR THIS TIME OF YEAR. LOWS IN
THE LOWER 60S NORTH(NEAR 60 ROXBORO)TO MID/UPPER 60S SOUTH. -CBL
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
AS OF 315 PM FRIDAY...
LOW-LEVEL DRY AIR FEED INTO THE AREA TO START THE WORK WEEK AS HIGH
PRESSURE BUILDS ACROSS THE OHIO VALLEY. CONVECTION IS EXPECTED TO BE
LARGELY SUPPRESSED TO OUR SOUTH ON MONDAY...AS S/W DISTURBANCES IN
THE NW FLOW ALOFT RUNNING ATOP THE LOW-LEVEL FRONTAL ZONE SOUTH OF
THE AREA COULD SUPPORT AN ORGANIZED SEVERE THREAT ACROSS THE DEEP
SOUTH. ONCE THE HIGH SHIFTS OFFSHORE ON TUESDAY...RETURN FLOW WILL
BRING A RETURN TO THE TYPICAL SUMMERTIME PATTERN FOR THE MID-WEEK
PERIOD...WITH ISOLATED TO SCATTERED AFTERNOON/EVENING SHOWERS AND
TSTMS.
RAIN CHANCES WILL INCREASE TOWARD LATE IN THE WORK WEEK AS AN
EASTWARD MOVING AREA OF LOW PRESSURE THROUGH GREAT LAKES AND
ATTENDANT TRAILING SURFACE FRONT APPROACH THE AREA ON THURSDAY
BEFORE POSSIBLY STALLING ACROSS THE REGION ON FRIDAY.
ADDITIONALLY...AS IS ALWAYS THE CASE WITH NW FLOW ALOFT DURING THE
SUMMER...CONVECTIVE CHANCES COULD BE AUGMENTED FURTHER BY THE TIMING
OF UPSTREAM CONVECTIVELY INDUCED/HYBRID VORTICITY CENTERS INTO THE
AREA. SEASONABLE TEMPERATURES ALL OF NEXT WEEK. HIGHS IN THE MID TO
UPPER 80S. LOWS IN THE MID 60 TO LOWER 70S.
&&
.AVIATION /00Z SATURDAY THROUGH WEDNESDAY/...
AS OF 820 PM FRIDAY...
24 HOUR TAF PERIOD: A FEW ISOLATED SHOWERS ARE LINGERING IN THE KFAY
AREA BUT SHOULD DISSIPATE IN THE FIRST COUPLE HOURS OF THE TAF
PERIOD. OVERNIGHT TONIGHT THERE WILL BE A CHANCE OF SOME MVFR
VISIBILITIES IN THE SOUTH AND EAST...PRIMARILY WHERE SHOWER ACTIVITY
HAS OCCURRED. CROSS SECTIONS SHOW FOG POSSIBLE AFTER 6Z IN THE EAST
AND AFTER 9Z FURTHER TO THE WEST. WILL KEEP ANY MENTION OUT OF THE
TRIAD TAFS AT THIS TIME. OTHERWISE A DRY NIGHT IS EXPECTED. WINDS
WILL BE LIGHT AND VARIABLE OVERNIGHT AND SHOULD BE SOUTHWESTERLY AT
5-10 KNOTS AFTER SUNRISE THROUGH THE END OF THE TAF PERIOD. A FEW
ISOLATED SHOWERS AND THUNDERSTORMS MAY BE POSSIBLE TOMORROW
AFTERNOON.
LONG TERM: MAINLY VFR CONDITIONS FOR THE REMAINDER OF SATURDAY
BEFORE A WEAK FRONT WILL PUSH SOUTHWARD INTO THE AREA ON
SUNDAY...BRINGING A CHANCE FOR SUB-VFR CONDITIONS. HIGH PRESSURE
WILL RETURN FOR MONDAY BEFORE CHANCES FOR CONVECTION INCREASE AGAIN
ON TUESDAY AND WEDNESDAY.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...BLS
NEAR TERM...BSD
SHORT TERM...BLS/CBL
LONG TERM...CBL
AVIATION...ELLIS
AREA FORECAST DISCUSSION
NWS RALEIGH NC
1017 AM EDT THU AUG 1 2013
.SYNOPSIS...
BENEATH AN APPROACHING UPPER LEVEL DISTURBANCE...A SURFACE TROUGH OF
LOW PRESSURE WILL DRIFT ACROSS CENTRAL AND EASTERN NC TODAY. A COLD
FRONT WILL FOLLOW AND SETTLE SOUTHEAST ACROSS THE REGION TONIGHT.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1015 AM THURSDAY...
THE LATEST SURFACE ANALYSIS SHOWED A WEAK TROUGH/COLD FRONT INTO THE
FOOTHILLS...SEPARATING THE MUCH MORE MOIST AIR...WITH DEW POINTS
MOSTLY IN THE LOWER 70S...FROM DRIER AND LOWER PW AIR BEHIND IT. THE
MORE NOTICEABLE WIND SHIFT BOUNDARY WAS LOCATED OVER THE OHIO
VALLEY...EXTENDING INTO KENTUCKY. THE LEAD BOUNDARY SHOULD NOT MOVE
MUCH DURING THE DAY AS THE FOLLOWING BOUNDARY CONTINUES TO MOVE
SOUTHEAST. MID-LEVEL DRYING ON WATER VAPOR WAS APPROACHING THE STATE
FROM THE WEST...AND ON THE 12Z UPPER-AIR ANALYSIS IT APPEARS THERE
WERE TWO MID-LEVEL SHORTWAVES...ONE MOVING THROUGH THE STATE
CURRENTLY DURING THE MORNING AND ANOTHER ASSOCIATED WITH THE STRONG
MID-LEVEL DRYING OVER KENTUCKY AND TENNESSEE. FOR THE AFTERNOON INTO
THE EVENING...THE GFS BUFR SOUNDINGS ARE MUCH MORE STABLE THAN THE
NAM AND RAP...WITH MID-LEVEL DRYING AND WARMING REDUCING POTENTIAL
INSTABILITY ESPECIALLY ALONG AND WEST OF ABOUT U.S. 1. JET SUPPORT
APPROACHING FROM THE WEST MAY JUST LAG PEAK HEATING...AND THE NAM
AND RAP SOUNDINGS SHOW GOOD LOW-LEVEL MOISTURE REMAINING THROUGHOUT
THE DAY...WHICH SHOULD RESULT IN A MOSTLY CLOUDY SKY ON AVERAGE
DESPITE SOME BREAKS. THE RAP FORECASTS MLCAPE RISING TO AS HIGH AS
2000J/KG TO 2500J/KG DURING THE AFTERNOON...WITH DCAPE AND
1000-500MB LAPSE RATES RISING AS THE DRIER AIR ALOFT MOVES IN FROM
THE WEST. GIVEN GREATER PEAK HEATING AND A STRONG SURFACE
BOUNDARY...VERY NUMEROUS SHOWERS AND THUNDERSTORMS MIGHT BE THE
RESULT...BUT MORE LIMITED HEATING AND LOW-LEVEL CONVERGENCE MAY END
UP LIMITING OVERALL LIFT. THE LATEST HRRR WRF HAS BEEN CONSISTENT
FROM ITS PREVIOUS COUPLE OF RUNS SHOWING MORE SCATTERED SHOWERS AND
THUNDERSTORMS LATE THIS AFTERNOON. HAVE MAINTAINED THE LOW LIKELY
CHANCES FOR SHOWERS AND SCATTERED THUNDERSTORMS MOST AREAS AS THERE
SHOULD BE ENOUGH COMBINED LIFT WITH THE WEAK SURFACE AND MODEST
UPPER-LEVEL FEATURES IN THE DEEPER MOISTURE FOR NUMEROUS SHOWERS. AS
THE DRIER AIR ALOFT MOVES IN FROM THE WEST...HELPING TO INCREASE
DOWNDRAFT CAPE...THERE IS THE CHANCE FOR AN ISOLATED SEVERE WIND
GUST. CURRENT THOUGHT IS THAT THE BETTER POTENTIAL FOR THAT WOULD BE
WEST OF I-95.
OVERNIGHT...DEEPER COLUMN DRYING GRADUALLY TAKES PLACE DIMINISHING
THE CHANCES FOR SHOWERS FROM WEST-TO-EAST AS THE PRIMARY SURFACE
FRONT MOVES IN AND CONTINUES A SLOW EASTWARD PROGRESSION.
PRECIPITABLE WATER VALUES IN THE TRIAD...BY 12Z FRIDAY...FALL TO
NEAR AN INCH...FROM 1.75 TO 2 INCHES TODAY. THE FRONT SHOULD LIKELY
NOT MAKE IT ALL THE WAY THROUGH CENTRAL NORTH CAROLINA...AND LIGHT
WINDS AND CONTINUED HIGH MOISTURE SHOULD RESULT IN AT LEAST PATCHY
FOG...IF NOT AREAS OF FOG AND LOCALLY DENSE FOG...PARTICULARLY OVER
THE COASTAL PLAIN. WILL AWAIT THE LATEST GUIDANCE BEFORE INTRODUCING
ANY FOG POTENTIAL IN THE HWO...BUT HAVE ADDED IT TO THE GRIDDED AND
WORDED FORECASTS. AFTER HIGHS TODAY MOSTLY IN THE MID 80S PROVIDING
THERE ARE SOME BREAKS IN THE CLOUDS...OVERNIGHT LOWS SHOULD RANGE
FROM THE MID 60S NORTHWEST TO AROUND 70 SOUTHEAST.
&&
.SHORT TERM /FRIDAY AND FRIDAY NIGHT/...
AS OF 330 AM THURSDAY...
STALLED SURFACE FRONT ACROSS EASTERN NC WILL SERVE TO FOCUS
CONVECTION ACROSS NC COASTAL COUNTIES FRIDAY AFTERNOON/EARLY FRIDAY
EVENING...PEAKING DURING THE MAX HEATING/DESTABILIZATION AND PERHAPS
AIDED BY THE MERGER OF THE SEABREEZE BOUNDARY. WILL ADD SLIGHT
CHANCE POPS FOR A FEW OF OUR FAR SOUTHEASTERN ZONES
(SAMPSON-WAYNE-CUMBERLAND). WEST OF THE FRONT...CONSIDERABLE DRYING
EXTENDING FROM THE MID-LEVELS TO THE SURFACE WILL STABILIZE THE
BOUNDARY LAYER AND SUPPRESS ANY LIFT. MUCH LIKE IT WAS AT THE START
OF THE WORK WEEK...SFC DEWPOINTS IN THE UPPER 50S TO LOWER 60S WILL
RESULT IN NOTICEABLY LOWER AND COMFORTABLE RH VALUES FOR EARLY
AUGUST. HIGHS IN THE MID 80S NW TO UPPER 80S SE.
STALLED FRONTAL ZONE WILL QUICKLY WASH OUT/DISSIPATE OVER THE AREA
FRIDAY NIGHT/EARLY SATURDAY WITH DEWPOINT RECOVERY INTO THE UPPER 60S
ACROSS THE PIEDMONT AND A LIGHTLY SELY SURFACE WIND. LOWS 67 TO 72.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
AS OF 330 AM THURSDAY...
THE UPPER AIR PATTERN OVER THE CONUS WHICH FEATURES AN UPPER LEVEL
RIDGE OVER THE ROCKIES...WHILE KEEPING AN UPPER LEVEL TROUGH OVER
THE EASTERN US...CHANGES VERY LITTLE THROUGH THE LONG TERM
PERIOD...POTENTIALLY BECOMING MORE AMPLIFIED BY EARLY/MIDDLE
PART OF NEXT WEEK. THIS WILL FAVOR A CONTINUATION OF SLIGHTLY BELOW
TO NEAR NORMAL TEMPERATURES THROUGH THE PERIOD.
AS FAR AS RAIN CHANCES...THE POTENTIAL FOR WELL TIMED LOW AMPLITUDE
S/W DISTURBANCES EMBEDDED IN THE WESTERLY FLOW ALOFT COULD COMBINE
WITH WEAK SURFACE CONVERGENCE ALONG THE LEE SIDE TROUGHINESS TO
SUPPORT ISOLATED TO WIDELY SCATTERED DIURNAL SHOWERS AND STORMS
ACROSS THE AREA SATURDAY AFTERNOON. HOWEVER ANOTHER SYNOPTIC SCALE
COLD FRONT WILL MOVE THROUGH THE AREA ON SUNDAY...AND WILL LIKELY
BRING OUR BEST RAIN CHANCES THROUGH THE WEEKEND. ANTECEDENT
WESTERLY FLOW ALOFT IN ADVANCE OF THE FRONTAL PASSAGE COULD IMPEDE
CONVECTIVE COVERAGE/POPS AND THUS WILL CAP POPS AT CHANCE.
THE COLD FRONT SHOULD SETTLE JUST SOUTH OF THE AREA SUNDAY
NIGHT/MONDAY AS WEAK HIGH PRESSURE BUILDS OVER THE OHIO VALLEY AND
MID-ATLANTIC STATES. FOR NOW WILL KEEP MONDAY DRY WITH RAIN CHANCES
RETURNING ON TUESDAY AS WAVES OF LOW PRESSURE DEVELOP ALONG THE
FRONT TO OUR SOUTH IN RESPONSE TO S/W ENERGY DIVING SE THROUGH THE
BASE OF THE TROUGH. SUCH A SET-UP WOULD RESULT IN CAD-LIKE SENSIBLE
WEATHER IMPACTS.
&&
.AVIATION /14Z THURSDAY THROUGH MONDAY/...
AS OF 1015 AM THURSDAY...
IFR-MVFR STRATUS OVER CENTRAL NC THIS MORNING WILL BE SLOW TO LIFT
AND SCATTER THROUGH MVFR RANGE TO VFR BETWEEN 15-18Z. NUMEROUS
SHOWERS AND SCATTERED THUNDERSTORMS ARE EXPECTED...BRINGING WITH
THEM PERIODS OF LOWER CEILINGS AND VISIBILITIES...AND POSSIBLY A
STRONG WIND GUST. IFR-LIFR CONDITIONS IN FOG WILL LIKELY REDEVELOP
LATE TONIGHT MAINLY FROM KRDU AND ESPECIALLY EASTWARD TO KRWI AND
KFAY...WHERE DRIER AIR BEHIND A SLOW-MOVING COLD FRONT WILL BE
SLOWEST TO ARRIVE.
LOOKING AHEAD: A SLIGHT CHANCE OF AFTERNOON SHOWERS AND STORMS AT
EASTERN TAF SITES FRIDAY AND SATURDAY...WITH A BETTER CHANCE -
AROUND 40 PERCENT - AT ALL CENTRAL NC TERMINALS ON SUNDAY.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...MWS
NEAR TERM...DJF
SHORT TERM...CBL
LONG TERM...CBL
AVIATION...MWS/DJF
AREA FORECAST DISCUSSION
NWS RALEIGH NC
215 AM EDT THU AUG 1 2013
.SYNOPSIS...
BENEATH AN APPROACHING UPPER LEVEL DISTURBANCE...A SURFACE TROUGH OF
LOW PRESSURE WILL DRIFT ACROSS CENTRAL AND EASTERN NC TODAY. A COLD
FRONT WILL FOLLOW AND SETTLE SOUTHEASTWARD ACROSS THE REGION
TONIGHT.
&&
.NEAR TERM /TONIGHT/...
AS OF 940 PM WEDNESDAY...
CURRENT BAND OF SHOWERS AND STORMS MOVING SLOWLY ACROSS WESTERN
PORTIONS OF THE AREA IS EXPECTED TO CONTINUE SLOWLY MOVING ACROSS
MOST OF THE AREA OVER THE NEXT 3-6 HOURS (LOWEST PROBABILITIES IN
THE SE/E)... WITH ADDITIONAL WEAK S/W ENERGY POSSIBLE LATER TONIGHT
MOVING THROUGH THE BROAD MID LEVEL CYCLONIC FLOW. HOWEVER... WITH
MLCAPE VALUES GENERALLY IN THE 500 TO 1000 J/KG OR LESS (ALONG WITH
NOCTURNAL STABILIZATION EXPECTED/UNDERWAY) DONT EXPECT ANY SEVERE
STORMS... THOUGH ISOLATED URBAN FLOODING WILL BE POSSIBLE AS PW`S
HAVE INCREASE INTO THE 1.8 TO 2.0" RANGE. WILL GO WITH POPS IN THE
LIKELY/CATEGORICAL RANGE FOR THE REST OF THE EVENING AND CHANCE POPS
AFTERWARD GIVEN THE MOIST AIRMASS AND ADDITIONAL S/W ENERGY (WITH
THE 850 MB TROUGH MOVING INTO THE AREA NEAR 12Z THURSDAY).
HOWEVER... THE LATEST HRRR GUIDANCE DOES NOT ADVERTISE MUCH AFTER
THIS CURRENT BAND MOVES THROUGH THE AREA... BUT THINK THE MOIST ATMO
AND POSSIBLE ADDITIONAL S/W ENERGY WARRANTS AT LEAST CHANCE POPS IN
THE WAKE OF THE CURRENT ACTIVITY. GIVEN THE EXPECTED CONSIDERABLE
CLOUD COVER... EXPECT LOW TEMPS WILL GENERALLY RANGE FROM UPPER
60S/NEAR 70 TO THE LOWER TO MAYBE EVEN MID 70S (MID 70S IN THE SE IF
THEY REMAIN DRY).
&&
.SHORT TERM /THURSDAY AND THURSDAY NIGHT/...
AS OF 230 PM WEDNESDAY...
LOOKING AT A CONTINUATION OF SHORTWAVE PERTURBATIONS MOVING EAST
ACROSS THE AREA INITIALLY ON THURSDAY. THESE WILL NUDGE THE SURFACE
FRONT EASTWARD INTO CENTRAL NC TOWARDS MID DAY. ENSUING DEEP LAYER
FORCING WILL BE WELL PHASED WITH ABUNDANT DEEP MOISTURE TO ASSIST
THE CONVECTIVE PROCESS DURING DIURNAL DESTABILIZATION. AS
SUCH...POPS WILL REMAIN IN THE LIKELY CATEGORY THROUGH LATE
AFTERNOON...WITH A BETTER CHANCE OF THUNDERSTORMS WITH DRY AIR
PUSHING IN BEHIND THE TROF PRODUCING MLCAPES >1500J AND MID LEVEL
LAPSE RATES STEEPENING TO 6.5K/KM. HIGHS WILL BE SIMILAR TO TODAY
GIVEN LACK OF INSOLATION AND SIMILAR AIRMASS...LOW 80S NORTHWEST TO
MID 80S IN THE SOUTHEAST.
WILL COMMENCE TAPERING THE POPS OFF IN THE WEST BY EVENING AS FLOW
FLATTENS AND BECOMES MORE WESTERLY BEHIND THE TROF. WILL KEEP SMALL
CHANCES IN THE EAST THROUGH AROUND MIDNIGHT. MINS WILL BE A LITTLE
COOLER GIVEN DRIER AIR AND GRADUAL CLEARING OVERNIGHT...65-70.
&&
.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
AS OF 258 PM WEDNESDAY...
CONTINUED GOOD MODEL AGREEMENT ON THE OVERALL PATTERN THROUGH EARLY
NEXT WEEK WITH AN UPPER LEVEL RIDGE REMAINING OVER THE ROCKIES...
AND UPPER LEVEL TROUGHING OVER THE EAST US... ALLOWING TEMPS A FEW
DEGREES BELOW NORMAL AND ABOVE NORMAL PRECIP CHANCES. DRIER AIR WILL
BRIEFLY MOVE IN TO THE AREA ON FRIDAY AFTER THE FRONT PASSES WITH
PWS PROGGED TO FALL TO NEAR AN INCH. MOISTURE WILL BEGIN TO REBOUND
OVER THE WEEKEND... AHEAD OF ANOTHER FRONT THAT LOOKS LIKELY TO PUSH
IN TO THE AREA FROM THE NORTH... POTENTIALLY MORE BACKDOOR IN
CHARACTER... SUNDAY INTO EARLY MONDAY. ANOTHER FRONT LOOKS TO
APPROACH THE AREA ON WEDNESDAY... ALTHOUGH UNCERTAINTY INCREASES AT
THIS TIME. THE MOST RECENT GFS RUN KEEPS THIS BOUNDARY WELL NORTH OF
THE AREA... AS IT FLATTENS THE EAST COAST TROUGH INTO A MORE ZONAL
FLOW. THIS OUTCOME IS NOT SUPPORTED BY ENSEMBLE MEANS... AND WILL
THEREFORE DISCOUNT AT THIS TIME. HIGHS WILL GENERALLY BE IN THE MID
TO UPPER 80S... LOWS MID 60S TO LOWER 70S.
&&
.AVIATION /06Z THURSDAY THROUGH MONDAY/...
AS OF 210 AM THURSDAY...
LIFR-VLIFR STRATUS OVER WESTERN NC...INCLUDING THE TRIAD
TERMINALS...WILL DEVELOP EASTWARD ACROSS THE REMAINDER OF CENTRAL NC
TAF SITES THROUGH AROUND 09Z. THESE CEILINGS WILL BE SLOW TO LIFT
AND SCATTER THROUGH MVFR RANGE TO VFR BETWEEN 16-19Z...PARTICULARLY
AT KRWI AND KFAY...WHERE MOIST SOUTH SOUTHWESTERLY FLOW WILL LINGER
LONGEST. THESE EASTERN TAF SITES ALSO STAND THE BEST CHANCE OF
EXPERIENCING SHOWERS AND ISOLATED THUNDERSTORMS THROUGH EARLY
AFTERNOON...WHILE CONVECTIVE COVERAGE ELSEWHERE WILL BE LESS -
WIDELY SCATTERED TO ISOLATED. A BROKEN LINE OF SHOWERS AND STORMS
IS EXPECTED TO FORM ALONG OR JUST AHEAD OF A COLD FRONT THAT WILL
CROSS CENTRAL NC LATE THIS AFTERNOON AND EARLY TONIGHT - AT TRIAD
TERMINALS BETWEEN 21-01Z AND EASTERN ONES BETWEEN 00-06Z. IFR-LIFR
CONDITIONS WILL LIKELY DEVELOP LATE TONIGHT MAINLY FROM KRDU AND
ESPECIALLY EASTWARD TO KRWI AND KFAY...WHERE DRIER AIR BEHIND THE
AFOREMENTIONED FRONT WILL BE SLOWEST TO ARRIVE.
LOOKING AHEAD: A SLIGHT CHANCE OF AFTERNOON SHOWERS AND STORMS AT
EASTERN TAF SITES SATURDAY...WITH A BETTER CHANCE - AROUND 40
PERCENT - AT ALL CENTRAL NC TERMINALS ON SUNDAY.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...MWS
NEAR TERM...BSD
SHORT TERM...MLM
LONG TERM...SEC
AVIATION...MWS
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1234 AM CDT THU AUG 1 2013
.UPDATE...
ISSUED AT 1233 AM CDT THU AUG 1 2013
NUDGE OVERNIGHT LOW TEMPERATURES DOWN A DEGREE OR TWO AS
TEMPERATURES ARE COOLING A BIT QUICKER UNDER MOSTLY CLEAR SKIES.
NO OTHER SIGNIFICANT CHANGES TO ONGOING FORECAST WERE MADE OTHER
THAN TO UPDATE FORECAST FOR LATEST OBS AND TRENDS.
UPDATE ISSUED AT 927 PM CDT WED JUL 31 2013
AT 9 PM CDT...LATEST RUC MODEL DEPICTS A RIDGE OF SURFACE HIGH
PRESSURE FROM EASTERN SOUTH DAKOTA NORTHWEST THROUGH SOUTHERN
SASKATCHEWAN. THE AREA OF HIGH PRESSURE WILL CONTINUE TO SLIDE
SOUTHEAST OVER THE REGION THROUGH THURSDAY. THIS WILL KEEP SKIES
MOSTLY CLEAR AND WINDS LIGHT NORTHWEST. COOL OVERNIGHT TEMPERATURES
WILL AGAIN BE IN THE OFFING WITH OVERNIGHT READINGS FROM THE UPPER
40S NORTHWEST AND CENTRAL TO THE LOWER 50S WESTERN DEVILS LAKE
BASIN. CURRENT FORECAST TENDING WELL.
UPDATE ISSUED AT 628 PM CDT WED JUL 31 2013
LATEST WATER VAPOR IMAGE SHOWS UPSTREAM SHORT WAVE MOVING THROUGH
EAST CENTRAL SASKATCHEWAN INTO MANITOBA NEAR LAKE WINNIPEG.
IMMEDIATELY UPSTREAM OF NORTH DAKOTA WEAK CHANNELED VORTICITY IN
NORTHWEST FLOW WILL BRING NO SIGNIFICANT FORCING THIS EVENING.
EXPECT NORTHWEST SURFACE FLOW TO DIMINISH OVERNIGHT AS REMAINING
CUMULUS FIELD DIMINISHES. CURRENT FORECAST LOOKS GOOD.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 304 PM CDT WED JUL 31 2013
MAIN HIGHLIGHTS IN THE SHORT TERM WILL BE THE POSSIBILITY OF A
SHOWER/SPRINKLES IN THE FAR NORTHEAST/TURTLE MOUNTAINS THURSDAY.
OTHERWISE EXPECT MOSTLY SUNNY...DRY...AND WARMER CONDITIONS.
THE LATEST SATELLITE IMAGERY SHOWS A SCATTERED TO AT TIMES A
BROKEN CUMULUS DECK ACROSS WESTERN AND CENTRAL NORTH DAKOTA. FOR
THE MOST PART EXPECT THE CUMULUS TO DISSIPATE TOWARD SUNSET.
WATER VAPOR IMAGERY SHOWS THE NEXT SHORTWAVE SLIDING SOUTHEAST
INTO CENTRAL SASKATCHEWAN THIS AFTERNOON. VISIBLE IMAGERY SHOWS
THICKER CLOUDS ACROSS SOUTH CENTRAL SASKATCHEWAN WITH SURFACE
OBSERVATIONS CLOSER TO THE SHORTWAVE REVEALING LIGHT RAIN AT
PRINCE ALBERT AND IN LA RONGE SASKATCHEWAN. HIGH RESOLUTION MODELS
ALONG WITH THE NAM/GFS/SREF KEEP THE PRECIPITATION ACROSS MANITOBA
THIS EVENING INTO TONIGHT...SO WILL NOT MENTION ANY POPS IN THE
TURTLE MOUNTAINS. THERE IS A REFLECTION OF A WEAK COLD FRONT AT
THE SURFACE...WHICH IS FORECAST TO REACH THE NORTHERN BORDER
BETWEEN 12Z AND 15Z THURSDAY. THE NAM SUGGESTS AN ISOLATED SHOWER
POSSIBLE NEAR THE INTERNATIONAL PEACE GARDEN PRIOR TO 18Z THURSDAY
ASSOCIATED WITH THE COLD FRONT...WHILE THE 09Z SREF ADVERTISES
SOME PRECIPITATION BETWEEN 18Z AND 21Z THURSDAY IN THE SAME AREA.
THE GFS/ECMWF ARE BOTH DRY. AFTER COORDINATING WITH GRAND
FORKS...WE AGREE THAT WE ARE NOT REAL CONFIDENT WITH MEASURABLE
PRECIPITATION AT THIS TIME. WILL LET THE EVENING AND NIGHT SHIFT
WATCH THE TRENDS AND ADJUST. ELSEWHERE...THE NAM/GFS SOUNDING
PROFILES SHOW A STRONG CAP IN PLACE ACROSS THE SOUTHWEST
THURSDAY AFTERNOON AND HAVE REMOVED THE SLIGHT CHC MENTION OF A
THUNDERSTORM. HIGHS THURSDAY WILL BE WARMER WITH AFTERNOON HIGHS
IN THE UPPER 70S TO LOWER 80S.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 304 PM CDT WED JUL 31 2013
ACTIVE NORTHWEST FLOW AND BELOW NORMAL TEMPERATURES WILL HIGHLIGHT
THE EXTENDED FORECAST.
OVERALL...THE 12 UTC GUIDANCE SUITE IS IN GOOD AGREEMENT ON
NORTHWEST FLOW ACROSS THE NORTHERN PLAINS THROUGH NEARLY THE
ENTIRE EXTENDED FORECAST PERIOD. THIS IS FORECAST TO RESULT IN
CONTINUED BELOW NORMAL TEMPERATURES WITH HIGHS IN THE 70S...WITH THE
COOLER EDGE OF GUIDANCE PREFERRED BASED UPON VERIFICATION OVER THE
PAST WEEK. WHILE IT IS HARD TO RULE OUT ISOLATED CONVECTION ANY
DAY IN A NORTHWEST FLOW REGIME...THE FAVORED TIME FRAME FOR
THUNDERSTORMS IS SATURDAY NIGHT THROUGH SUNDAY AS ENERGY FROM THE
PACIFIC NORTHWEST PROPAGATES ALONG THE CREST OF THE RIDGE INTO THE
NORTHERN PLAINS. AN EARLY LOOK AT SHEAR AND INSTABILITY PROFILES
SUGGESTS SEVERE STORMS MAY BE POSSIBLE DURING THIS TIME FRAME. THE
12 UTC GFS/ECMWF CONTINUE TO DEPICT AN ANOMALOUSLY DEEP UPPER LEVEL
LOW ACROSS SOUTH CANADA AND POSSIBLY INTO THE FAR NORTH CENTRAL
CONUS NEXT WEDNESDAY THROUGH FRIDAY. WILL CONTINUE TO MONITOR AS
THIS COULD RESULT IN SIGNIFICANTLY BELOW NORMAL TEMPERATURES.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1233 AM CDT THU AUG 1 2013
HIGH PRESSURE OVERHEAD WILL CONTINUE MOSTLY CLEAR SKIES AND LIGHT
WINDS. VFR CONDITIONS FORECAST AT ALL TAF SITES THROUGH THE 06Z
TAF PERIOD.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...LTH
SHORT TERM...KS
LONG TERM...AYD
AVIATION...LTH
AREA FORECAST DISCUSSION...UPDATED
NWS CLEVELAND OH
508 PM EDT THU AUG 1 2013
.SYNOPSIS...
A TROUGH OF LOW PRESSURE WILL MOVE THROUGH THE AREA THIS EVENING.
HIGH PRESSURE OVER WESTERN TENNESSEE WILL MOVE EAST ACROSS THE
TENNESSEE VALLEY AND EXTEND A RIDGE NORTH INTO OHIO AND PENNSYLVANIA
THROUGH EARLY FRIDAY AFTERNOON. A TROUGH OF LOW PRESSURE WILL MOVE
EAST ACROSS THE REGION FRIDAY AFTERNOON AND EVENING. HIGH PRESSURE
WILL MOVE SOUTHEAST ACROSS THE AREA SUNDAY AND BE OFF THE EAST COAST
AND BY TUESDAY.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
TWEAKED THE TIMING OF THE CONVECTION ACROSS THE AREA THIS EVENING.
ALSO CHANGED CHANCE WORDING TO SCATTERED FOR THIS EVENING.
ORIGINAL DISCUSSION...
UPPER LEVEL TROUGH AND ASSOCIATED POSITIVE VORTICITY
MAXIMUM WILL MOVE EAST ACROSS THE REGION OVERNIGHT. NEARLY SILENT
SURFACE TROUGH WAS NOT VERY ACTIVE THIS MORNING BUT DECIDED TO
MAKE ITS PRESENCE KNOWN BY FIRING SOME THUNDERSTORMS ALONG THE
LINE. I WAS A BIT CONCERNED ABOUT THIS FEATURE BEFORE THE LAST
UPDATE BUT LITTLE IN THE WAY OF ACTIVITY WAS ASSOCIATED WITH THE
FEATURE. SO...BACK TRACKED AND ADDED A MENTION OF SHOWERS AND
THUNDERSTORMS THIS EVENING AS THE TROUGH AXIS MOVES EAST ACROSS
THE AREA.
OTHER THAN THE THREAT FOR THUNDERSTORMS THIS EVENING...WE SHOULD SEE
DIMINISHING CHANCES FOR PRECIPITATION BY MIDNIGHT AND A RETURN TO
FAIR WEATHER FOR THE OVERNIGHT HOURS AS NEGATIVE VORTICITY ADVECTION
FOLLOWS THE TROUGH INTO THE REGION.
TEMPERATURES OVERNIGHT SHOULD HOVER IN THE LOWER 60S OVERNIGHT BUT
SHOULD BE A FEW DEGREES COLDER THAN LAST NIGHT. COLD AIR MASS BEHIND
THE FRONT RESULTED IN MOSTLY DRIER AIR RATHER THAN A SIGNIFICANT
DROP IN TEMPERATURES.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH SUNDAY NIGHT/...
SURFACE HIGH PRESSURE RIDGE WILL BUILD EAST ACROSS THE AREA TOMORROW
MORNING AND THEN THAT FEATURE WILL BE FOLLOWED BY ANOTHER WEAK
APPROACHING COLD FRONT AND ASSOCIATED MOISTURE. SO WILL KEEP A
CHANCE FOR SHOWERS AND THUNDERSTORMS GOING IN THE AFTERNOON. I THINK
THE BETTER CHANCE MAY HOLD OFF UNTIL LATER IN THE DAY INTO FRIDAY
NIGHT.
COLD FRONT SLIPS THROUGH LATE FRIDAY NIGHT INTO SATURDAY MORNING
WITH SOME UPPER LEVEL SUPPORT THAT APPEARS TO STAY OVER THE NORTHERN
TIER COUNTIES AND LAKE ERIE. ANOTHER SHOT OF POSITIVE VORTICITY
SCOOTS IN ACROSS THE AREA SATURDAY AFTERNOON AND NIGHT AND THIS
COULD SET OFF SOME AFTERNOON AND EARLY EVENING THUNDERSTORMS.
FINALLY...BY SUNDAY MORNING...MUCH DRIER AIR...SURFACE HIGH PRESSURE
AND FAIRLY STRONG NEGATIVE VORTICITY ADVECTION MOVE SOUTHEAST INTO
THE AREA AND WE SHOULD SEE ANOTHER ROUND OF FAIR WEATHER. AS SURFACE
HIGH PRESSURE BUILDS SOUTHEAST...FORECAST AREA SHOULD SEE A SLIGHT
INCREASE IN THE WINDS TO PRODUCE A GENTLE BREEZE THROUGH THE DAY
INTO SUNDAY NIGHT. FAIR WEATHER CONTINUES SUNDAY NIGHT UNDER THE
INFLUENCE OF THE HIGH PRESSURE.
TEMPERATURES SHOULD JUMP BACK UP INTO THE MIDDLE TO UPPER 70S ON
FRIDAY AHEAD OF THE COLD FRONT. CLOUDS AND SHOWERS WILL HELP BLANKET
THE AREA AND KEEP TEMPERATURES UP IN THE MIDDLE 60S THROUGH THE
NIGHT. SOME LOWER 60S IN THE VALLEYS EXTREME EASTERN ERIE AND
CRAWFORD COUNTIES IN PENNSYLVANIA.
THEN ON SATURDAY AFTER COLD FRONTAL PASSAGE WILL LIKELY SEE
TEMPERATURES DROP BACK INTO THE MIDDLE 70S NORTH TO UPPER 70S IN THE
WEST. AS FAIR WEATHER RETURNS SATURDAY NIGHT INTO SUNDAY COOLER
TEMPERATURES IN THE 50S CAN BE EXPECTED FOLLOWED BY HIGHS IN THE
LOWER TO MIDDLE 70S. WARMER TEMPERATURES EXPECTED IN THE WEST.
SUNDAY NIGHT TEMPERATURES SIMILAR TO SATURDAY NIGHT.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
LITTLE CHANGE TO LARGE SCALE PATTERN DURING THIS PERIOD AS THE
UPPER LEVEL TROUGH REMAINS IN PLACE OVER ONTARIO AND QUEBEC WHICH
WILL KEEP CONDITIONS COOLER THAN NORMAL AND AT TIMES UNSETTLED.
HAVE GENERALLY USED THE ECMWF FOR TIMING PRECIPITATION INTO THE
REGION AS THE GFS AND ECMWF DIVERGE SOMEWHAT BEGINNING ON TUESDAY.
WILL KEEP TUESDAY DRY WITH LOW CHANCE AND SLIGHT CHANCE POPS ON
WEDNESDAY AND THURSDAY.
&&
.AVIATION /21Z THURSDAY THROUGH TUESDAY/...
LOW CLOUDS HAVE LIFTED AND DECREASED IN COVERAGE IN THE EAST
WHILE INSTABILITY AND CONVECTIVE DEVELOPMENT HAS TAKEN PLACE OVER
LOWER MICHIGAN AND NORTHERN INDIANA. SCATTERED SHOWERS AND
THUNDERSTORMS HAVE DEVELOPED NEAR TOL. THE HRRR MODEL HAS A DECENT
HANDLE ON THIS ACTIVITY AND MOVES SOUTHEAST MOSTLY AROUND LAKE
ERIE AND DISSIPATES IT BEFORE SUNSET. WILL MENTION VCSH AT TOL,
FDY AND MFD AND LEAVE THE OTHER TAF SITES DRY.
BOUNDARY LAYER MOISTURE WILL REMAIN HIGH OVERNIGHT AND WITH LIGHT
WINDS AND CLEARING SKIES...DENSE FOG MAY DEVELOP DOWN TO IFR VSBY
NEAR YNG FROM 10-12 UTC. LIGHTER FOG IS POSSIBLE NEAR CAK. IF
AFTERNOON SHOWERS REACH OTHER TAF SITES FOG MAY NEED TO BE ADDED.
MODEL SOUNDINGS SHOW THE MOISTURE LAPSE INCREASING WITH HEIGHT
NEAR YNG OVERNIGHT WHICH INDICATES FAVORABLE CONDITIONS FOR FOG
DEVELOPMENT.
.OUTLOOK...AREAS OF NON-VFR FRIDAY NIGHT INTO SATURDAY WITH SHOWERS.
&&
.MARINE...
SMALL CRAFT CONDITIONS PREVAIL OVER THE LAKE AT MID AFTERNOON.
EXPECT THE PRESSURE GRADIENT TO WEAKEN THIS EVENING ALLOWING THE
EXPIRATION OF THE SCA AT 00UTC. MODERATE RISK OF RIP CURRENTS WILL
LINGER TO ABOUT 22 UTC. ANOTHER TROUGH/WEAK FRONT WILL MOVE ACROSS
THE LAKE FRIDAY NIGHT AND PRODUCE WINDS OF 10 TO 20 KNOTS WITH WAVES
OF 2-4 FEET. HIGH PRESSURE WILL GRADUALLY BUILD OVER THE LAKE LATE
SATURDAY NIGHT AND SUNDAY WITH WEST TO NORTHWEST FLOW OF 5 TO 15
KNOTS. A SMALL CRAFT ADVISORY MAY BE NEEDED ON SUNDAY. HIGH PRESSURE
WILL LINGER NEAR THE LAKE MONDAY AND TUESDAY AND PRODUCE LIGHT WINDS.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR
LEZ145>149.
&&
$$
SYNOPSIS...LOMBARDY
NEAR TERM...DJB/LOMBARDY
SHORT TERM...LOMBARDY
LONG TERM...LAPLANTE
AVIATION...LAPLANTE
MARINE...LAPLANTE
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
347 PM EDT THU AUG 1 2013
.SYNOPSIS...
A TROUGH OF LOW PRESSURE WILL MOVE THROUGH THE AREA THIS EVENING.
HIGH PRESSURE OVER WESTERN TENNESSEE WILL MOVE EAST ACROSS THE
TENNESSEE VALLEY AND EXTEND A RIDGE NORTH INTO OHIO AND PENNSYLVANIA
THROUGH EARLY FRIDAY AFTERNOON. A TROUGH OF LOW PRESSURE WILL MOVE
EAST ACROSS THE REGION FRIDAY AFTERNOON AND EVENING. HIGH PRESSURE
WILL MOVE SOUTHEAST ACROSS THE AREA SUNDAY AND BE OFF THE EAST COAST
AND BY TUESDAY.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
UPPER LEVEL TROUGH AND ASSOCIATED POSITIVE VORTICITY MAXIMUM WILL
MOVE EAST ACROSS THE REGION OVERNIGHT. NEARLY SILENT SURFACE TROUGH
WAS NOT VERY ACTIVE THIS MORNING BUT DECIDED TO MAKE ITS PRESENCE
KNOWN BY FIRING SOME THUNDERSTORMS ALONG THE LINE. I WAS A BIT
CONCERNED ABOUT THIS FEATURE BEFORE THE LAST UPDATE BUT LITTLE IN
THE WAY OF ACTIVITY WAS ASSOCIATED WITH THE FEATURE. SO...BACK
TRACKED AND ADDED A MENTION OF SHOWERS AND THUNDERSTORMS THIS
EVENING AS THE TROUGH AXIS MOVES EAST ACROSS THE AREA.
OTHER THAN THE THREAT FOR THUNDERSTORMS THIS EVENING...WE SHOULD SEE
DIMINISHING CHANCES FOR PRECIPITATION BY MIDNIGHT AND A RETURN TO
FAIR WEATHER FOR THE OVERNIGHT HOURS AS NEGATIVE VORTICITY ADVECTION
FOLLOWS THE TROUGH INTO THE REGION.
TEMPERATURES OVERNIGHT SHOULD HOVER IN THE LOWER 60S OVERNIGHT BUT
SHOULD BE A FEW DEGREES COLDER THAN LAST NIGHT. COLD AIR MASS BEHIND
THE FRONT RESULTED IN MOSTLY DRIER AIR RATHER THAN A SIGNIFICANT
DROP IN TEMPERATURES.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH SUNDAY NIGHT/...
SURFACE HIGH PRESSURE RIDGE WILL BUILD EAST ACROSS THE AREA TOMORROW
MORNING AND THEN THAT FEATURE WILL BE FOLLOWED BY ANOTHER WEAK
APPROACHING COLD FRONT AND ASSOCIATED MOISTURE. SO WILL KEEP A
CHANCE FOR SHOWERS AND THUNDERSTORMS GOING IN THE AFTERNOON. I THINK
THE BETTER CHANCE MAY HOLD OFF UNTIL LATER IN THE DAY INTO FRIDAY
NIGHT.
COLD FRONT SLIPS THROUGH LATE FRIDAY NIGHT INTO SATURDAY MORNING
WITH SOME UPPER LEVEL SUPPORT THAT APPEARS TO STAY OVER THE NORTHERN
TIER COUNTIES AND LAKE ERIE. ANOTHER SHOT OF POSITIVE VORTICITY
SCOOTS IN ACROSS THE AREA SATURDAY AFTERNOON AND NIGHT AND THIS
COULD SET OFF SOME AFTERNOON AND EARLY EVENING THUNDERSTORMS.
FINALLY...BY SUNDAY MORNING...MUCH DRIER AIR...SURFACE HIGH PRESSURE
AND FAIRLY STRONG NEGATIVE VORTICITY ADVECTION MOVE SOUTHEAST INTO
THE AREA AND WE SHOULD SEE ANOTHER ROUND OF FAIR WEATHER. AS SURFACE
HIGH PRESSURE BUILDS SOUTHEAST...FORECAST AREA SHOULD SEE A SLIGHT
INCREASE IN THE WINDS TO PRODUCE A GENTLE BREEZE THROUGH THE DAY
INTO SUNDAY NIGHT. FAIR WEATHER CONTINUES SUNDAY NIGHT UNDER THE
INFLUENCE OF THE HIGH PRESSURE.
TEMPERATURES SHOULD JUMP BACK UP INTO THE MIDDLE TO UPPER 70S ON
FRIDAY AHEAD OF THE COLD FRONT. CLOUDS AND SHOWERS WILL HELP BLANKET
THE AREA AND KEEP TEMPERATURES UP IN THE MIDDLE 60S THROUGH THE
NIGHT. SOME LOWER 60S IN THE VALLEYS EXTREME EASTERN ERIE AND
CRAWFORD COUNTIES IN PENNSYLVANIA.
THEN ON SATURDAY AFTER COLD FRONTAL PASSAGE WILL LIKELY SEE
TEMPERATURES DROP BACK INTO THE MIDDLE 70S NORTH TO UPPER 70S IN THE
WEST. AS FAIR WEATHER RETURNS SATURDAY NIGHT INTO SUNDAY COOLER
TEMPERATURES IN THE 50S CAN BE EXPECTED FOLLOWED BY HIGHS IN THE
LOWER TO MIDDLE 70S. WARMER TEMPERATURES EXPECTED IN THE WEST.
SUNDAY NIGHT TEMPERATURES SIMILAR TO SATURDAY NIGHT.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
LITTLE CHANGE TO LARGE SCALE PATTERN DURING THIS PERIOD AS THE
UPPER LEVEL TROUGH REMAINS IN PLACE OVER ONTARIO AND QUEBEC WHICH
WILL KEEP CONDITIONS COOLER THAN NORMAL AND AT TIMES UNSETTLED.
HAVE GENERALLY USED THE ECMWF FOR TIMING PRECIPITATION INTO THE
REGION AS THE GFS AND ECMWF DIVERGE SOMEWHAT BEGINNING ON TUESDAY.
WILL KEEP TUESDAY DRY WITH LOW CHANCE AND SLIGHT CHANCE POPS ON
WEDNESDAY AND THURSDAY.
&&
.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
LOW CLOUDS HAVE LIFTED AND DECREASED IN COVERAGE IN THE EAST
WHILE INSTABILITY AND CONVECTIVE DEVELOPMENT HAS TAKEN PLACE OVER
LOWER MICHIGAN AND NORTHERN INDIANA. SCATTERED SHOWERS AND
THUNDERSTORMS HAVE DEVELOPED NEAR TOL. THE HRRR MODEL HAS A DECENT
HANDLE ON THIS ACTIVITY AND MOVES SOUTHEAST MOSTLY AROUND LAKE
ERIE AND DISSIPATES IT BEFORE SUNSET. WILL MENTION VCSH AT TOL,
FDY AND MFD AND LEAVE THE OTHER TAF SITES DRY.
BOUNDARY LAYER MOISTURE WILL REMAIN HIGH OVERNIGHT AND WITH LIGHT
WINDS AND CLEARING SKIES...DENSE FOG MAY DEVELOP DOWN TO IFR VSBY
NEAR YNG FROM 10-12 UTC. LIGHTER FOG IS POSSIBLE NEAR CAK. IF
AFTERNOON SHOWERS REACH OTHER TAF SITES FOG MAY NEED TO BE ADDED.
MODEL SOUNDINGS SHOW THE MOISTURE LAPSE INCREASING WITH HEIGHT
NEAR YNG OVERNIGHT WHICH INDICATES FAVORABLE CONDITIONS FOR FOG
DEVELOPMENT.
.OUTLOOK...AREAS OF NON-VFR FRIDAY NIGHT INTO SATURDAY WITH SHOWERS.
&&
.MARINE...
SMALL CRAFT CONDITIONS PREVAIL OVER THE LAKE AT MID AFTERNOON.
EXPECT THE PRESSURE GRADIENT TO WEAKEN THIS EVENING ALLOWING THE
EXPIRATION OF THE SCA AT 00UTC. MODERATE RISK OF RIP CURRENTS WILL
LINGER TO ABOUT 22 UTC. ANOTHER TROUGH/WEAK FRONT WILL MOVE ACROSS
THE LAKE FRIDAY NIGHT AND PRODUCE WINDS OF 10 TO 20 KNOTS WITH WAVES
OF 2-4 FEET. HIGH PRESSURE WILL GRADUALLY BUILD OVER THE LAKE LATE
SATURDAY NIGHT AND SUNDAY WITH WEST TO NORTHWEST FLOW OF 5 TO 15
KNOTS. A SMALL CRAFT ADVISORY MAY BE NEEDED ON SUNDAY. HIGH PRESSURE
WILL LINGER NEAR THE LAKE MONDAY AND TUESDAY AND PRODUCE LIGHT WINDS.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR
LEZ145>149.
&&
$$
SYNOPSIS...LOMBARDY
NEAR TERM...LOMBARDY
SHORT TERM...LOMBARDY
LONG TERM...LAPLANTE
AVIATION...LAPLANTE
MARINE...LAPLANTE
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
217 PM EDT THU AUG 1 2013
.SYNOPSIS...
A COLD FRONT WILL CROSS THE AREA EARLY TODAY. WEAK HIGH PRESSURE
WILL FOLLOW....BUILDING IN THIS AFTERNOON AND EVENING. A SECOND
COLD FRONT WILL MOVE THROUGH ON SATURDAY. CANADIAN HIGH PRESSURE
WILL BUILD SOUTHEAST ACROSS THE GREAT LAKES SUNDAY INTO MONDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
CLOUDS ARE BECOMING MORE DIURNAL AND CONVECTIVE THIS AFTERNOON AS
COLD FRONT PULLS AWAY TO THE EAST FAIRLY QUICKLY. DRIER AIR IS
ALSO WORKING INTO THE REGION AIDING IN CLEARING THE SKIES OUT AND
PROVIDE MORE SUNSHINE. DECIDED TO PULL PRECIPITATION OUT OF THE
WESTERN AREAS AND LEAVE A MENTION OF SLIGHT CHANCE IN THE EXTREME
EAST FOR A LITTLE WHILE LONGER.
BUMPED TEMPERATURES DOWN A DEGREE OR TWO TO ACCOUNT FOR THE COLD
AIR ADVECTION.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY NIGHT/...
FOLLOWED A NAM/GFS MIX THROUGH THE SHORT TERM FORECAST WITH
GRIDDED POPS SHADED TOWARD THE SREF WHICH WAS IN HINDSIGHT VERY
GOOD LAST NIGHT. THIS EVENING THE AXIS OF THE UPPER TROF OVER THE
GREAT LAKES REGION WILL BE IN EASTERN OHIO WITH WEAK HIGH PRESSURE
BUILDING IN FROM THE WEST/SOUTHWEST. EXPECTING DRY CONDITIONS
THROUGH THE NIGHT WITH GENERALLY PC SKIES. NEXT SHORT WAVE ALREADY
DROPPING OUT OF THE NRN PLAINS AND BY FRIDAY MORNING COLD FRONT
WILL EXTEND ACROSS LAKE MI WITH THE JET ENERGY MOVING ACROSS SRN
LWR MI. SREF BROUGHT CHC POPS INTO WESTERN COUNTIES THROUGH THE
MORNING FRIDAY AND EVERYWHERE DURING THE AFTERNOON AND NIGHT.
SATURDAY MORNING MODELS BEGINNING TO DIFFER A BIT ON ORIENTATION
AND POSITION OF DEVELOPING MOISTURE WITH THE APPROACHING COLD
FRONT. GFS A JUST A BUT FURTHER SOUTH WITH MOISTURE AND MORE
EAST/WEST VS NW/SE WITH THE NAM. FOLLOWED GFS MORE CLOSELY WITH
MOISTURE DROPPING SOUTH THROUGH THE AFTERNOON. SATURDAY NIGHT AND
SUNDAY SHOULD BE DRY WITH ANOTHER HIGH BUILDING IN.
&&
.LONG TERM /MONDAY THROUGH WEDNESDAY/...
UPPER LEVEL TROUGH WILL REMAIN ANCHORED OVER THE GREAT LAKES REGION
THROUGH THE DURATION OF THE EXTENDED FORECAST. BELOW NORMAL
TEMPERATURES WILL CONTINUE WITH HIGHS GENERALLY IN THE MID 70S.
HIGH PRESSURE AT THE SURFACE WILL BE CENTERED OVER OHIO ON
MONDAY...BUILDING TOWARDS THE MID-ATLANTIC OVERNIGHT. THE 12Z/31
ECMWF WAS FASTER IN RETURNING LOW LEVEL MOISTURE AND A CHANCE OF
SHOWERS BACK INTO THE AREA ON MONDAY WHILE THE 00Z/01 CONSENSUS IS
DRIER WITH ISENTROPIC ASCENT AND BETTER CHANCES OF SHOWERS REMAINING
SW OF THE AREA AND PRIMARILY DURING THE MONDAY NIGHT AND TUESDAY
TIME FRAME. THE GOING FORECAST HAS A GOOD HANDLE ON THIS WITH JUST A
20 POP IN THE WEST ON MONDAY...INCREASING TO A 30 PERCENT CHANCE ON
TUESDAY...THEN BACKING OFF AGAIN TOWARDS WEDNESDAY.
&&
.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
LOW CLOUDS HAVE LIFTED AND DECREASED IN COVERAGE IN THE EAST WHILE
INSTABILITY AND CONVECTIVE DEVELOPMENT HAS TAKEN PLACE OVER LOWER
MICHIGAN AND NORTHERN INDIANA. SCATTERED SHOWERS AND THUNDERSTORMS
HAVE DEVELOPED NEAR TOL. THE HRRR MODEL HAS A DECENT HANDLE ON
THIS ACTIVITY AND MOVES SOUTHEAST MOSTLY AROUND LAKE ERIE AND
DISSIPATES IT BEFORE SUNSET. WILL MENTION VCSH AT TOL, FDY AND MFD
AND LEAVE THE OTHER TAF SITES DRY.
BOUNDARY LAYER MOISTURE WILL REMAIN HIGH OVERNIGHT AND WITH LIGHT
WINDS AND CLEARING SKIES...DENSE FOG MAY DEVELOP DOWN TO IFR VSBY
NEAR YNG FROM 10-12 UTC. LIGHTER FOG IS POSSIBLE NEAR CAK. IF
AFTERNOON SHOWERS REACH OTHER TAF SITES FOG MAY NEED TO BE ADDED.
MODEL SOUNDINGS SHOW THE MOISTURE LAPSE INCREASING WITH HEIGHT
NEAR YNG OVERNIGHT WHICH INDICATES FAVORABLE CONDITIONS FOR FOG
DEVELOPMENT.
.OUTLOOK...AREAS OF NON-VFR FRIDAY NIGHT INTO SATURDAY WITH SHOWERS.
&&
.MARINE...
WINDS INCREASED OVER THE LAKE OUT OF THE NORTHWEST AND THEREFORE
ARE STRONG ENOUGH TO SUPPORT WAVES UP TO 4 FEET ALONG THE SHORE.
WILL ISSUE A SMALL CRAFT ADVISORY WITH THIS UPDATE.
PREVIOUS DISCUSSION...
SOUTHWESTERLY WINDS WILL BRIEFLY BE ELEVATED AHEAD OF A WEAK
FRONT CROSSING THE LAKE EARLY THIS MORNING. WESTERLY WINDS OF 10
TO NEAR 20 KNOTS ON THE EAST END OF THE LAKE CAN BE EXPECTED
BEHIND THE FRONT TODAY. WAVES WILL INCREASE TO 2 TO 4 FEET ON THE
EAST HALF OF THE LAKE AND PRESENT A MODERATE RISK OF RIP CURRENTS.
ANOTHER WEAK TROUGH WILL CROSS THE LAKE ON FRIDAY AND MAINTAIN
10-15 KNOT SOUTHWESTERLY WINDS. HIGH PRESSURE WILL BUILD OVER THE
LAKE LATE SATURDAY INTO SUNDAY WITH WINDS SHIFTING TO NORTHERLY
NEAR 10 KNOTS AND 1-3 FOOT WAVES WITH THE ONSHORE FLOW.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR
LEZ145>149.
&&
$$
SYNOPSIS...TK
NEAR TERM...LOMBARDY
SHORT TERM...TK
LONG TERM...KEC
AVIATION...LAPLANTE
MARINE...KEC
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
156 AM EDT THU AUG 1 2013
.SYNOPSIS...
A WEAK COLD FRONT CROSSES LATE TONIGHT AND EARLY THURSDAY. HIGH
PRESSURE PASSES THURSDAY NIGHT/FRIDAY MORNING. A COLD FRONT CROSSES
THIS WEEKEND...FOLLOWED BY BELOW NORMAL TEMPERATURES EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH TODAY/...
130 AM UPDATE...NO SIGNIFICANT CHANGE.
PREVIOUS DISCUSSION...
DISTURBANCE MOVING THRU CWA WITH MAINLY SCT -SHRA AND EVEN SOME
-DZ ABOUT THE AREA. WEAKENING VORT MAX HANGING OUT ACROSS SE OH CO
WITH LOBE APPENDAGE MOVING NE INTO N WV SERVING AS MAIN FOCUS FOR
LIFT. RUC AND HRRR SEEMS TO HAVE A MUCH BETTER HANDLE ON THINGS VS
OTHER MDLS AND HAVE USED THESE AS GUIDANCE. OTHERWISE LOOKING AT
AN ABUNDANCE OF LLVL MOISTURE REMAINDER OF AFTN.
FRONT POISED TO MOVE THRU LATE TONIGHT INTO EARLY THU MORNING WITH
A BAND OF SHRA WITH IT. THERE COULD BE AN AREA OF -RA OR DZ ALONG
AND E OF I79 TONIGHT BEFORE AFOREMENTIONED SHRA ARRIVE WITH
IMPRESSIVE DRYING SHOWING UP IN MID LVLS. THINK LOW STRATUS AND
FG WILL SETUP REGARDLESS THIS EVE...TRYING TO LIFT SOME AS FRONTAL
SHRA MOVE IN PREDAWN.
ALL OF THIS PUSHES E ON THU WITH AMPLIFYING UPR TROF ACROSS OH
VALLEY. HOWEVER...LLVL MOISTURE WILL BE VERY SLOW TO GIVE UP THE
GHOST. EVEN THOUGH LOW STRATUS LIFTS BY MIDDAY...SUSPECT THIS WILL
GIVE WAY TO AN ABUNDANCE OF CU GIVEN H85 MOISTURE UNDERNEATH A
DEVELOPING STOUT INVERSION ARND H7. AS FOR POPS DRY THINGS OUT FOR
MOST PART. DID LEAVE SOME LOW POPS FOR A FEW EARLY AFTN DEVELOPMENT
ACROSS THE MTNS.
FOR TEMPS...INHERITED NUMBERS LOOKED GOOD TONIGHT. ELECTED TO GO
CLOSER TO COOLER MET ON THU WITH EXPECTATION THAT EXTENT OF CLDS
HOLDS NUMBERS DOWN A BIT.
&&
.SHORT TERM /TONIGHT THROUGH SATURDAY NIGHT/...
A FEW OF THE MESO MODELS ARE SHOWING SOME LINGERING SHOWERS BEHIND
THE COLD FRONT THURSDAY NIGHT. DUE TO THE TIME OF DAY AND DRY AIR
PUSH...DO NOT THINK THAT THIS IS REALISTIC. WILL LEAVE DRY FOR NOW.
HIGH PRESSURE THEN PROVIDES A BRIEF PERIOD OF DRY WEATHER FRIDAY
MORNING. ALL MODELS ARE SHOWING SOME MOISTURE PUSHING BACK IN LATE
FRIDAY...ALTHOUGH TIMING DIFFERENCES EXIST. WILL INCLUDE A CHANCE OF
SHOWERS...AND POSSIBLY THUNDERSTORMS...BUT NOT BE TOO DEFINITIVE. WILL
INCREASE POPS INTO SATURDAY AS FRONT APPROACHES AND MOISTURE
DEEPENS. FRONT THEN PUSHES THROUGH LATE SATURDAY/SATURDAY NIGHT.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
LOTS OF MODEL DIFFERENCES IN HOW FAR SOUTH THE FRONT AND MOISTURE
PUSH FOR THE END OF THE WEEKEND AND BEGINNING OF NEXT WEEK. USED A
BLEND OF THE ECMWF MEAN AND THE GEFS...WHICH WOULD PUT THE FRONT
JUST SOUTH OF THE FORECAST AREA. WITH SOME WAVES POSSIBLE ALONG THE
FRONT...SOME PRECIPITATION COULD MAKE IT INTO THE FORECAST
AREA...WITH THE BEST CHANCES IN THE SOUTH.
&&
.AVIATION /06Z THURSDAY THROUGH MONDAY/...
06Z THURSDAY THRU 06Z FRIDAY ...
WIDESPREAD MVFR CIGS HAVE DEVELOPED OVERNIGHT...ALONG WITH LOCAL
IFR CIGS...PARTICULARLY ALONG AND EAST OF A KCKB TO KCRW LINE.
THESE WILL LAST THROUGH AROUND 14-16Z...WHEN GRADUAL LIFTING TO
LOW VFR IS EXPECTED. STILL SOME SCATTERED SHOWERS/ISOLD
THUNDERSTORMS EXPECTED THRU 00Z AS A COLD FRONT APPROACHES THE
REGION...WITH BRIEF MVFR CONDITIONS IN VICINITY.
AFTER 00Z...AREAS THAT CLEAR WILL SEE IFR FOG DEVELOPING AFTER
06Z. MOUNTAIN TAF SITES SUCH AS AT KEKN OR KBKW WILL SEE EITHER
LOW STRATUS LINGERING...OR FOG.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 06Z FRIDAY...
FORECAST CONFIDENCE: LOW TO MEDIUM.
ALTERNATE SCENARIOS: DEVELOPMENT OF LOW STRATUS/FOG OVERNIGHT MAY
VARY FROM CURRENT FORECAST. TIMING OF FRONT AND SHRA TONIGHT MAY
VARY. DEVELOPMENT OF FOG AND/OR LOW STRATUS TONIGHT MAY VARY FROM FORECAST.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
DATE THU 08/01/13
UTC 1HRLY 06 07 08 09 10 11 12 13 14 15 16 17
EDT 1HRLY 02 03 04 05 06 07 08 09 10 11 12 13
CRW CONSISTENCY H H L L L L L L H H H M
HTS CONSISTENCY M H L L L L L M H H H M
BKW CONSISTENCY H M M M H H H H H H H M
EKN CONSISTENCY H H M M M H H H H H H H
PKB CONSISTENCY H H H L L L M H H H H M
CKB CONSISTENCY H H H M M L H M H H H M
AFTER 06Z FRIDAY...
IFR POSSIBLE IN SHOWERS AND THUNDERSTORMS LATE FRIDAY THROUGH
SATURDAY NIGHT.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...RPY/30
NEAR TERM...SL/30
SHORT TERM...RPY
LONG TERM...RPY
AVIATION...SL
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
1112 PM EDT FRI AUG 2 2013
.SYNOPSIS...
A DEVELOPING LARGE HIGH LATITUDE BLOCK OVER NORTHERN CANADA WILL
FORCE SHORT-WAVE ENERGY INTO EASTERN NORTH AMERICA FOR MOST OF
THE NEXT 7 DAYS OR MORE. THE RESULT WILL BE A PERIOD OF RELATIVELY
COOL DRY WEATHER WITH A MID-TROPOSPHERIC TROUGH OVER OUR REGION.
A WEAK SURGE OF MOISTURE AHEAD OF ONE WAVE IN THE FLOW WILL
TRIGGER SHOWERS EARLY SATURDAY A SECOND POTENTIAL SURGE OF
MOISTURE WITH ANOTHER WAVE COULD BRING ANOTHER CHANCE OF SHOWERS
AFTER WEDNESDAY OR THURSDAY.
&&
.NEAR TERM /UNTIL 9 AM SATURDAY MORNING/...
RADAR SHOWS SOME LIGHT SHOWERS MOVING ACROSS PORTIONS OF WARREN
AND MCKEAN COUNTIES AND NOW INTO CLEARFIELD COUNTY. MOST OF THE
LIGHT RAIN IS NOT LIKELY REACHING THE GROUND IN MANY PLACES. A
MORE ORGANIZED BAND AREA OF RAIN IS OVER WESTERN PA AND HEADED
RAPIDLY TO THE EAST-SOUTHEAST.
THERE IS MORE RAIN TO THE WEST OVER OHIO AND WITH WESTERLY FLOW
OVER A GENERAL E-W SAGGING BOUNDARY GOING TO BE A SLOW PUSH FOR
THIS BOUNDARY TO WORK INTO SOUTHERN PA OVERNIGHT AND INTO
SATURDAY.
MOST SITES SHOW LIGHT RAIN BUT 1 OR 2 OBSERVATIONS UNDER AN
ENHANCE ECHO SHOW 3 BALL RAIN. MODIFIED GRIDS TO REFLECT THE RAIN
OVER WESTERN PA. NUDGED GRIDS TOWARD AM WITH HRRR AND BLEND
PREVIOUS GUIDANCE. STILL TRIED TO KEEP QPF LOW AND POPS IN MOST
LOCATIONS IN THE CHANCE CATEGORY AS THIS SHOULD NOT BE A
SIGNIFICANT RAINFALL. HIGHEST POPS IN THE 40-54 PERCENT RANGE SORT
OF ACROSS OUR CENTRAL AND WESTERN AREAS.
LOW PROBABILITY OF MUCH OVER 0.05 TO 0.10 INCHES BY SUNRISE AND
MOST GUIDANCE IMPLIES HIGHER POPS SLIDE TO SOUTHEAST TOWARD
SUNRISE.
&&
.SHORT TERM /9 AM SATURDAY MORNING THROUGH SATURDAY NIGHT/...
MODELS CONTINUE TO SHOW HIGHER POPS FARTHER SOUTH NEAR MASON-DIXON
LINE AND LOWER POPS TO NORTH. SHOULD BE A LIGHT EVENT AS PW IS ON
THE LOW SIDE. TRIED TO SHOW POP GRADIENT LOWER TO NORTH AND HIGHER
TO SOUTH NEAR MD BORDER LATER IN THE DAY.
MINOR ADJUSTMENTS TO TEMPERATURES.
PREVIOUS FORECAST:
THE 18Z GEFS SHOWS BEST CHANCE RAINFALL ABOUT 8-2 PM ALONG MASON-
DIXON LINE DROPPING OFF FAST TO NORTH. HARD FOR MOST MODELS TO
CRANK OUT MORE THAN A FEW HUNDREDTHS OF A QPF. SREF FROM 15Z WAS
WETTER BUT IT TOO FOCUSED HIGHEST POPS NEAR MASON-DIXON LINE.
NORTHERN AREAS SHOULD BE RAIN FREE AND EXPECT WIDELY SCATTERED
SHOWERS AND THUNDER IN CENTRAL. SHOWERS IN SOUTHERN AREAS NEAR THE
LOW-LEVEL BOUNDARY SHOULD MOSTLY BE LIGHT AND SHOULD CLEAR MOST OF
THE AREA BY MID AFTERNOON. GOOD NEWS IS PW IS NEAR NORMAL AND
DROPS IN THE LATE AFTERNOON...PRETTY DRY COLUMN OF AIR OVER PA SO
NOT A LOT TO WORK WITH.
JUST A NOTE THAT THE WINDS QUITE STRONG AND PARALLEL TO THE
BOUNDARY IN SOUTHERN PA. IF WE GET ANY THUNDERSTORMS THEY HAVE SOME
GOOD WINDS TO TAP. GOOD NEWS IS THE CAPE IS REALLY LOW SO LARGE
UPDRAFTS ARE NOT LIKELY TO DEVELOP.
&&
.LONG TERM /SUNDAY THROUGH FRIDAY/...
CONSENSUS AMONG MED RANGE GUIDANCE FOR ANOTHER STRETCH OF
COOL/DRY WX SUNDAY INTO EARLY NEXT WEEK...AS COLD FRONT PRESSES
SOUTH OF PA AND COOL...CANADIAN HIGH PRES BUILDS SE ACROSS THE
AREA. 00Z GEFS 8H TEMPS REMAIN BLW NORMAL SUN-MON WHEN DAYTIME
MAXES WILL LIKELY BE 5-10F BLW NORMAL. NEGATIVE PWAT AND 8H TEMPS
ANOMALIES IN THE ENSEMBLE OUTPUT POINT TOWARD AN IDEAL SETUP FOR
RADIATIONAL COOLING MONDAY AND TUESDAY NIGHTS...AS SFC HIGH DRIFTS
OVR THE AREA. FOR MANY PARTS OF CENTRAL PA THESE COULD BE THE
COOLEST NIGHTS OF THE SUMMER SEASON. NORTHERN MTNS WILL BE SOLIDLY
IN THE 40S...WITH LOWER TO MID 50S ELSEWHERE.
AXIS OF UPPER TROUGH SHIFTS FROM THE NORTHEAST CONUS TO THE
MIDWEST BY THE MID/LATE NEXT WEEK...INDICATING SLIGHTLY
WARMER...MORE HUMID AIR WILL MAKE A RETURN. CAN/T RULE OUT AN
ISOLD SHRA/TSRA CREEPING INTO THE SC MTNS AS EARLY AS TUE AFTN -
AS HINTED BY BOTH THE EC/GFS. HOWEVER...THE NEXT CHANCE FOR
WIDESPREAD PRECIPITATION WILL LIKELY NOT COME UNTIL LATE WED WITH
ARRIVAL OF A WARM FRONT OR AN EVEN BETTER CHANCE THURSDAY AS NEXT
COLD FRONT SLOWS AS IT PUSHES THROUGH.
&&
.AVIATION /03Z SATURDAY THROUGH WEDNESDAY/...
DID ADJUST 03Z TAF PACKAGE SOME. SHOWERS A LITTLE MORE
WIDESPREAD THAN I EXPECTED...BUT NOTHING MAJOR. TEMPS
AT MID LVLS WERE QUITE COLD TO THE NORTH THIS AFT...BUT
NO INSTABILITY LEFT NOW FOR THUNDER.
EARLIER DISCUSSION BELOW.
LACK OF LOW LVL MOISTURE AND CURRENT RADAR AND SATELLITE
TRENDS...THINK ANY MAJOR WEATHER WOULD BE SOUTH AND WEST OF
OUR AREA LATE TONIGHT. THUS WENT WITH VCSH FOR NOW.
LEFT FOG OUT OF BFD LATE...GIVEN MID LVL CLDS...AND
LACK OF HIGH DEWPTS.
FOR SAT...AS NOTED ABOVE...DATA AND MODELS HINT THAT
MOST OF THE SHOWERS AND STORMS WOULD BE SOUTH OF CENTRAL
PA...THUS WENT WITH VCSH FOR NOW.
COOLER AND DRIER CONDITIONS FOR SUNDAY INTO TUE...MAINLY
VFR CONDITIONS.
OUTLOOK...
SUN-WED...VFR. NO SIG WX. AM FOG POSSIBLE. PERHAPS
A SHOWER LATE WED.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...GRUMM
NEAR TERM...GRUMM
SHORT TERM...GRUMM/RXR
LONG TERM...RXR
AVIATION...MARTIN
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
1059 PM EDT FRI AUG 2 2013
.SYNOPSIS...
A DEVELOPING LARGE HIGH LATITUDE BLOCK OVER NORTHERN CANADA WILL
FORCE SHORT-WAVE ENERGY INTO EASTERN NORTH AMERICA FOR MOST OF
THE NEXT 7 DAYS OR MORE. THE RESULT WILL BE A PERIOD OF RELATIVELY
COOL DRY WEATHER WITH A MID-TROPOSPHERIC TROUGH OVER OUR REGION.
A WEAK SURGE OF MOISTURE AHEAD OF ONE WAVE IN THE FLOW WILL
TRIGGER SHOWERS EARLY SATURDAY A SECOND POTENTIAL SURGE OF
MOISTURE WITH ANOTHER WAVE COULD BRING ANOTHER CHANCE OF SHOWERS
AFTER WEDNESDAY OR THURSDAY.
&&
.NEAR TERM /UNTIL 9 AM SATURDAY MORNING/...
RADAR SHOWS SOME LIGHT SHOWERS MOVING ACROSS PORTIONS OF WARREN
AND MCKEAN COUNTIES AND NOW INTO CLEARFIELD COUNTY. MOST OF THE
LIGHT RAIN IS NOT LIKELY REACHING THE GROUND IN MANY PLACES. A
MORE ORGANIZED BAND AREA OF RAIN IS OVER WESTERN PA AND HEADED
RAPIDLY TO THE EAST-SOUTHEAST.
THERE IS MORE RAIN TO THE WEST OVER OHIO AND WITH WESTERLY FLOW
OVER A GENERAL E-W SAGGING BOUNDARY GOING TO BE A SLOW PUSH FOR
THIS BOUNDARY TO WORK INTO SOUTHERN PA OVERNIGHT AND INTO
SATURDAY.
MOST SITES SHOW LIGHT RAIN BUT 1 OR 2 OBSERVATIONS UNDER AN
ENHANCE ECHO SHOW 3 BALL RAIN. MODIFIED GRIDS TO REFLECT THE RAIN
OVER WESTERN PA. NUDGED GRIDS TOWARD AM WITH HRRR AND BLEND
PREVIOUS GUIDANCE. STILL TRIED TO KEEP QPF LOW AND POPS IN MOST
LOCATIONS IN THE CHANCE CATEGORY AS THIS SHOULD NOT BE A
SIGNIFICANT RAINFALL. HIGHEST POPS IN THE 40-54 PERCENT RANGE SORT
OF ACROSS OUR CENTRAL AND WESTERN AREAS.
LOW PROBABILITY OF MUCH OVER 0.05 TO 0.10 INCHES BY SUNRISE AND
MOST GUIDANCE IMPLIES HIGHER POPS SLIDE TO SOUTHEAST TOWARD
SUNRISE.
&&
.SHORT TERM /9 AM SATURDAY MORNING THROUGH SATURDAY NIGHT/...
MODELS CONTINUE TO SHOW HIGHER POPS FARTHER SOUTH NEAR MASON-DIXON
LINE AND LOWER POPS TO NORTH. SHOULD BE A LIGHT EVENT AS PW IS ON
THE LOW SIDE. TRIED TO SHOW POP GRADIENT LOWER TO NORTH AND HIGHER
TO SOUTH NEAR MD BORDER LATER IN THE DAY.
MINOR ADJUSTMENTS TO TEMPERATURES.
PREVIOUS FORECAST:
THE 18Z GEFS SHOWS BEST CHANCE RAINFALL ABOUT 8-2 PM ALONG MASON-
DIXON LINE DROPPING OFF FAST TO NORTH. HARD FOR MOST MODELS TO
CRANK OUT MORE THAN A FEW HUNDREDTHS OF A QPF. SREF FROM 15Z WAS
WETTER BUT IT TOO FOCUSED HIGHEST POPS NEAR MASON-DIXON LINE.
NORTHERN AREAS SHOULD BE RAIN FREE AND EXPECT WIDELY SCATTERED
SHOWERS AND THUNDER IN CENTRAL. SHOWERS IN SOUTHERN AREAS NEAR THE
LOW-LEVEL BOUNDARY SHOULD MOSTLY BE LIGHT AND SHOULD CLEAR MOST OF
THE AREA BY MID AFTERNOON. GOOD NEWS IS PW IS NEAR NORMAL AND
DROPS IN THE LATE AFTERNOON...PRETTY DRY COLUMN OF AIR OVER PA SO
NOT A LOT TO WORK WITH.
JUST A NOTE THAT THE WINDS QUITE STRONG AND PARALLEL TO THE
BOUNDARY IN SOUTHERN PA. IF WE GET ANY THUNDERSTORMS THEY HAVE SOME
GOOD WINDS TO TAP. GOOD NEWS IS THE CAPE IS REALLY LOW SO LARGE
UPDRAFTS ARE NOT LIKELY TO DEVELOP.
&&
.LONG TERM /SUNDAY THROUGH FRIDAY/...
CONSENSUS AMONG MED RANGE GUIDANCE FOR ANOTHER STRETCH OF
COOL/DRY WX SUNDAY INTO EARLY NEXT WEEK...AS COLD FRONT PRESSES
SOUTH OF PA AND COOL...CANADIAN HIGH PRES BUILDS SE ACROSS THE
AREA. 00Z GEFS 8H TEMPS REMAIN BLW NORMAL SUN-MON WHEN DAYTIME
MAXES WILL LIKELY BE 5-10F BLW NORMAL. NEGATIVE PWAT AND 8H TEMPS
ANOMALIES IN THE ENSEMBLE OUTPUT POINT TOWARD AN IDEAL SETUP FOR
RADIATIONAL COOLING MONDAY AND TUESDAY NIGHTS...AS SFC HIGH DRIFTS
OVR THE AREA. FOR MANY PARTS OF CENTRAL PA THESE COULD BE THE
COOLEST NIGHTS OF THE SUMMER SEASON. NORTHERN MTNS WILL BE SOLIDLY
IN THE 40S...WITH LOWER TO MID 50S ELSEWHERE.
AXIS OF UPPER TROUGH SHIFTS FROM THE NORTHEAST CONUS TO THE
MIDWEST BY THE MID/LATE NEXT WEEK...INDICATING SLIGHTLY
WARMER...MORE HUMID AIR WILL MAKE A RETURN. CAN/T RULE OUT AN
ISOLD SHRA/TSRA CREEPING INTO THE SC MTNS AS EARLY AS TUE AFTN -
AS HINTED BY BOTH THE EC/GFS. HOWEVER...THE NEXT CHANCE FOR
WIDESPREAD PRECIPITATION WILL LIKELY NOT COME UNTIL LATE WED WITH
ARRIVAL OF A WARM FRONT OR AN EVEN BETTER CHANCE THURSDAY AS NEXT
COLD FRONT SLOWS AS IT PUSHES THROUGH.
&&
.AVIATION /03Z SATURDAY THROUGH WEDNESDAY/...
LACK OF LOW LVL MOISTURE AND CURRENT RADAR AND SATELLITE
TRENDS...THINK ANY MAJOR WEATHER WOULD BE SOUTH AND WEST
OF OUR AREA LATE TONIGHT. THUS WENT WITH VCSH FOR NOW.
LEFT FOG OUT OF BFD LATE...GIVEN MID LVL CLDS...AND
LACK OF HIGH DEWPTS.
FOR SAT...AS NOTED ABOVE...DATA AND MODELS HINT THAT
MOST OF THE SHOWERS AND STORMS WOULD BE SOUTH OF CENTRAL
PA...THUS WENT WITH VCSH FOR NOW.
COOLER AND DRIER CONDITIONS FOR SUNDAY INTO TUE...MAINLY
VFR CONDITIONS.
OUTLOOK...
SUN-WED...VFR. NO SIG WX. AM FOG POSSIBLE. PERHAPS
A SHOWER LATE WED.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...GRUMM
NEAR TERM...GRUMM
SHORT TERM...GRUMM/RXR
LONG TERM...RXR
AVIATION...MARTIN
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
1005 PM EDT FRI AUG 2 2013
.SYNOPSIS...
A DEVELOPING LARGE HIGH LATITUDE BLOCK OVER NORTHERN CANADA WILL
FORCE SHORT-WAVE ENERGY INTO EASTERN NORTH AMERICA FOR MOST OF
THE NEXT 7 DAYS OR MORE. THE RESULT WILL BE A PERIOD OF RELATIVELY
COOL DRY WEATHER WITH A MID-TROPOSPHERIC TROUGH OVER OUR REGION.
A WEAK SURGE OF MOISTURE AHEAD OF ONE WAVE IN THE FLOW WILL
TRIGGER SHOWERS EARLY SATURDAY A SECOND POTENTIAL SURGE OF
MOISTURE WITH ANOTHER WAVE COULD BRING ANOTHER CHANCE OF SHOWERS
AFTER WEDNESDAY OR THURSDAY.
&&
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
LOTS OF HIGH AND MID CLOUDS ABOUT. MODELS WERE A BIT OVERDONE ON
SHOWER POTENTIAL THIS EVENING IN THE WEST. CURRENTLY BEST AREAS OF
SHOWERS ARE WELL WEST IN OH. SATELLITE SHOWS THE SHORT WAVE ENERGY
HEADING OUR WAY IN THE FAST NORTHWEST FLOW. MOST AREAS SHOULD
REMAIN FREE OVERNIGHT. BEST CHANCE OF RAIN IN WEST WHERE POPS ARE
IN THE CHANCE RANGE.
HIGH RESOLUTION MODELS SUGGEST SHOWER IN WESTERN AREAS AFTER ABOUT
MIDNIGHT AND WEAKEN AS PUSH TO THE SOUTHEAST BY ABOUT 6-8 AM.
THE CLOUDS IN THEORY SHOULD KEEP THE TEMPERATURES UP A BIT. UPPER
50S IN THE NORTH AND TO MID 60S IN SOUTH WITH SOME MORE URBAN
AREAS IN UPPER 60S.
&&
.SHORT TERM /6 AM SATURDAY MORNING THROUGH SATURDAY NIGHT/...
NO
KEEP LOWERING POPS AS NEW GUIDANCE COMES IN. THE 18Z 4KM NAM AND
RECENT RAP RUNS IMPLY SOME LIGHT SHOWERS IN SOUTHERN PA SATURDAY
MORNING SO CHANCE POPS DOWN THERE TO START THE DAY. THIS PUSHES
OUT BY 9-10 AM TO THE SOUTH. THEN CONVECTION IS SPOTTY IN CENTRAL
PA IN AFTERNOON AND UNORGANIZED. WE ARE IN A SEE TEXT AREA.
BUT ALL THE GUIDANCE TENDS TO BE WET IN THE SUMMER FOR THESE LOW
END AMOUNTS. LEANED LOWER THAN GUIDANCE BUT THIS LEFT MOST OF
SOUTHERN PA IN THE CHANCE RANGE FOR SHOWERS AND SLIGHT CHANCE IN
CENTRAL AREAS...WHERE AS MENTIONED THE HIGHER RESOLUTION MODELS
SHOW MOST CONVECTIVE POTENTIAL.
THE 18Z GEFS SHOWS BEST CHANCE RAINFALL ABOUT 8-2 PM ALONG MASON-
DIXON LINE DROPPING OFF FAST TO NORTH. HARD FOR MOST MODELS TO
CRANK OUT MORE THAN A FEW HUNDREDTHS OF A QPF. SREF FROM 15Z WAS
WETTER BUT IT TOO FOCUSED HIGHEST POPS NEAR MASON-DIXON LINE.
NORTHERN AREAS SHOULD BE RAIN FREE AND EXPECT WIDELY SCATTERED
SHOWERS AND THUNDER IN CENTRAL. SHOWERS IN SOUTHERN AREAS NEAR THE
LOW-LEVEL BOUNDARY SHOULD MOSTLY BE LIGHT AND SHOULD CLEAR MOST OF
THE AREA BY MID AFTERNOON. GOOD NEWS IS PW IS NEAR NORMAL AND
DROPS IN THE LATE AFTERNOON...PRETTY DRY COLUMN OF AIR OVER PA SO
NOT A LOT TO WORK WITH.
JUST A NOTE THAT THE WINDS QUITE STRONG AND PARALLEL TO THE
BOUNDARY IN SOUTHERN PA. IF WE GET ANY THUNDERSTORMS THEY HAVE SOME
GOOD WINDS TO TAP. GOOD NEWS IS THE CAPE IS REALLY LOW SO LARGE
UPDRAFTS ARE NOT LIKELY TO DEVELOP.
&&
.LONG TERM /SUNDAY THROUGH FRIDAY/...
CONSENSUS AMONG MED RANGE GUIDANCE FOR ANOTHER STRETCH OF
COOL/DRY WX SUNDAY INTO EARLY NEXT WEEK...AS COLD FRONT PRESSES
SOUTH OF PA AND COOL...CANADIAN HIGH PRES BUILDS SE ACROSS THE
AREA. 00Z GEFS 8H TEMPS REMAIN BLW NORMAL SUN-MON WHEN DAYTIME
MAXES WILL LIKELY BE 5-10F BLW NORMAL. NEGATIVE PWAT AND 8H TEMPS
ANOMALIES IN THE ENSEMBLE OUTPUT POINT TOWARD AN IDEAL SETUP FOR
RADIATIONAL COOLING MONDAY AND TUESDAY NIGHTS...AS SFC HIGH DRIFTS
OVR THE AREA. FOR MANY PARTS OF CENTRAL PA THESE COULD BE THE
COOLEST NIGHTS OF THE SUMMER SEASON. NORTHERN MTNS WILL BE SOLIDLY
IN THE 40S...WITH LOWER TO MID 50S ELSEWHERE.
AXIS OF UPPER TROUGH SHIFTS FROM THE NORTHEAST CONUS TO THE
MIDWEST BY THE MID/LATE NEXT WEEK...INDICATING SLIGHTLY
WARMER...MORE HUMID AIR WILL MAKE A RETURN. CAN/T RULE OUT AN
ISOLD SHRA/TSRA CREEPING INTO THE SC MTNS AS EARLY AS TUE AFTN -
AS HINTED BY BOTH THE EC/GFS. HOWEVER...THE NEXT CHANCE FOR
WIDESPREAD PRECIPITATION WILL LIKELY NOT COME UNTIL LATE WED WITH
ARRIVAL OF A WARM FRONT OR AN EVEN BETTER CHANCE THURSDAY AS NEXT
COLD FRONT SLOWS AS IT PUSHES THROUGH.
&&
.AVIATION /02Z SATURDAY THROUGH WEDNESDAY/...
LACK OF LOW LVL MOISTURE AND CURRENT RADAR AND SATELLITE
TRENDS...THINK ANY MAJOR WEATHER WOULD BE SOUTH AND WEST
OF OUR AREA LATE TONIGHT. THUS WENT WITH VCSH FOR NOW.
LEFT FOG OUT OF BFD LATE...GIVEN MID LVL CLDS...AND
LACK OF HIGH DEWPTS.
FOR SAT...AS NOTED ABOVE...DATA AND MODELS HINT THAT
MOST OF THE SHOWERS AND STORMS WOULD BE SOUTH OF CENTRAL
PA...THUS WENT WITH VCSH FOR NOW.
COOLER AND DRIER CONDITIONS FOR SUNDAY INTO TUE...MAINLY
VFR CONDITIONS.
OUTLOOK...
SUN-WED...VFR. NO SIG WX. AM FOG POSSIBLE. PERHAPS
A SHOWER LATE WED.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...GRUMM
NEAR TERM...GRUMM
SHORT TERM...GRUMM/RXR
LONG TERM...RXR
AVIATION...MARTIN
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
816 PM EDT FRI AUG 2 2013
.SYNOPSIS...
A WEAK WAVE IN THE NORTHWESTERLY FLOW WILL PUSH A SECONDARY FRONT
INTO PA OVERNIGHT INTO SATURDAY. THIS COULD TRIGGER SOME SHOWERS
AND THUNDERSTORMS. DRY AIR MOVES INTO THE STATE SATURDAY AND AN
UNSEASONABLY COOL AND DRY AIRMASS WILL FILTER INTO THE AREA BEHIND
THE FRONT SUNDAY INTO MONDAY. THE NEXT FRONTAL SYSTEM SHOULD
APPROACH THE AREA BY THE MIDDLE TO LATER PART OF NEXT WEEK.
&&
.NEAR TERM /UNTIL 8 AM SATURDAY MORNING/...
LOTS OF HIGH AND MID CLOUDS ABOUT. MODELS WERE A BIT OVERDONE ON
SHOWER POTENTIAL THIS EVENING IN THE WEST. CURRENTLY BEST AREAS OF
SHOWERS ARE WELL WEST IN OH. SATELLITE SHOWS THE SHORT WAVE ENERGY
HEADING OUR WAY IN THE FAST NORTHWEST FLOW. MOST AREAS SHOULD
REMAIN FREE OVERNIGHT. BEST CHANCE OF RAIN IN WEST WHERE POPS ARE
IN THE CHANCE RANGE.
HIGH RESOLUTION MODELS SUGGEST SHOWER IN WESTERN AREAS AFTER ABOUT
MIDNIGHT AND WEAKEN AS PUSH TO THE SOUTHEAST BY ABOUT 6-8 AM.
THE CLOUDS IN THEORY SHOULD KEEP THE TEMPERATURES UP A BIT. UPPER
50S IN THE NORTH AND TO MID 60S IN SOUTH WITH SOME MORE URBAN
AREAS IN UPPER 60S.
&&
.SHORT TERM /8 AM SATURDAY MORNING THROUGH SATURDAY NIGHT/... NO
KEEP LOWERING POPS AS NEW GUIDANCE COMES IN. THE 18Z 4KM NAM AND
RECENT RAP RUNS IMPLY SOME LIGHT SHOWERS IN SOUTHERN PA SATURDAY
MORNING SO CHANCE POPS DOWN THERE TO START THE DAY. THIS PUSHES
OUT BY 9-10 AM TO THE SOUTH. THEN CONVECTION IS SPOTTY IN CENTRAL
PA IN AFTERNOON AND UNORGANIZED. WE ARE IN A SEE TEXT AREA.
BUT ALL THE GUIDANCE TENDS TO BE WET IN THE SUMMER FOR THESE LOW
END AMOUNTS. LEANED LOWER THAN GUIDANCE BUT THIS LEFT MOST OF
SOUTHERN PA IN THE CHANCE RANGE FOR SHOWERS AND SLIGHT CHANCE IN
CENTRAL AREAS...WHERE AS MENTIONED THE HIGHER RESOLUTION MODELS
SHOW MOST CONVECTIVE POTENTIAL.
THE 18Z GEFS SHOWS BEST CHANCE RAINFALL ABOUT 8-2 PM ALONG MASON-
DIXON LINE DROPPING OFF FAST TO NORTH. HARD FOR MOST MODELS TO
CRANK OUT MORE THAN A FEW HUNDREDTHS OF A QPF. SREF FROM 15Z WAS
WETTER BUT IT TOO FOCUSED HIGHEST POPS NEAR MASON-DIXON LINE.
NORTHERN AREAS SHOULD BE RAIN FREE AND EXPECT WIDELY SCATTERED
SHOWERS AND THUNDER IN CENTRAL. SHOWERS IN SOUTHERN AREAS NEAR THE
LOW-LEVEL BOUNDARY SHOULD MOSTLY BE LIGHT AND SHOULD CLEAR MOST OF
THE AREA BY MID AFTERNOON. GOOD NEWS IS PW IS NEAR NORMAL AND
DROPS IN THE LATE AFTERNOON...PRETTY DRY COLUMN OF AIR OVER PA SO
NOT A LOT TO WORK WITH.
JUST A NOTE THAT THE WINDS QUITE STRONG AND PARALLEL TO THE
BOUNDARY IN SOUTHERN PA. IF WE GET ANY THUNDERSTORMS THEY HAVE SOME
GOOD WINDS TO TAP. GOOD NEWS IS THE CAPE IS REALLY LOW SO LARGE
UPDRAFTS ARE NOT LIKELY TO DEVELOP.
&&
.LONG TERM /SUNDAY THROUGH FRIDAY/...
CONSENSUS AMONG MED RANGE GUIDANCE FOR ANOTHER STRETCH OF
COOL/DRY WX SUNDAY INTO EARLY NEXT WEEK...AS COLD FRONT PRESSES
SOUTH OF PA AND COOL...CANADIAN HIGH PRES BUILDS SE ACROSS THE
AREA. 00Z GEFS 8H TEMPS REMAIN BLW NORMAL SUN-MON WHEN DAYTIME
MAXES WILL LIKELY BE 5-10F BLW NORMAL. NEGATIVE PWAT AND 8H TEMPS
ANOMALIES IN THE ENSEMBLE OUTPUT POINT TOWARD AN IDEAL SETUP FOR
RADIATIONAL COOLING MONDAY AND TUESDAY NIGHTS...AS SFC HIGH DRIFTS
OVR THE AREA. FOR MANY PARTS OF CENTRAL PA THESE COULD BE THE
COOLEST NIGHTS OF THE SUMMER SEASON. NORTHERN MTNS WILL BE SOLIDLY
IN THE 40S...WITH LOWER TO MID 50S ELSEWHERE.
AXIS OF UPPER TROUGH SHIFTS FROM THE NORTHEAST CONUS TO THE
MIDWEST BY THE MID/LATE NEXT WEEK...INDICATING SLIGHTLY
WARMER...MORE HUMID AIR WILL MAKE A RETURN. CAN/T RULE OUT AN
ISOLD SHRA/TSRA CREEPING INTO THE SC MTNS AS EARLY AS TUE AFTN -
AS HINTED BY BOTH THE EC/GFS. HOWEVER...THE NEXT CHANCE FOR
WIDESPREAD PRECIPITATION WILL LIKELY NOT COME UNTIL LATE WED WITH
ARRIVAL OF A WARM FRONT OR AN EVEN BETTER CHANCE THURSDAY AS NEXT
COLD FRONT SLOWS AS IT PUSHES THROUGH.
&&
.AVIATION /00Z SATURDAY THROUGH WEDNESDAY/...
LACK OF LOW LVL MOISTURE AND CURRENT RADAR AND SATELLITE
TRENDS...THINK ANY MAJOR WEATHER WOULD BE SOUTH AND WEST
OF OUR AREA LATE TONIGHT. THUS WENT WITH VCSH FOR NOW.
LEFT FOG OUT OF BFD LATE...GIVEN MID LVL CLDS...AND
LACK OF HIGH DEWPTS.
FOR SAT...AS NOTED ABOVE...DATA AND MODELS HINT THAT
MOST OF THE SHOWERS AND STORMS WOULD BE SOUTH OF CENTRAL
PA...THUS WENT WITH VCSH FOR NOW.
COOLER AND DRIER CONDITIONS FOR SUNDAY INTO TUE...MAINLY
VFR CONDITIONS.
OUTLOOK...
SUN-WED...VFR. NO SIG WX. AM FOG POSSIBLE. PERHAPS
A SHOWER LATE WED.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...GRUMM/DEVOIR
NEAR TERM...GRUMM
SHORT TERM...GRUMM/RXR
LONG TERM...RXR
AVIATION...MARTIN
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
502 PM EDT THU AUG 1 2013
.SYNOPSIS...
A WEAK COLD FRONT WILL CROSS THE REGION TODAY...BEFORE HIGH PRESSURE
BUILDS IN FROM THE NORTHWEST FRIDAY AND LINGERS INTO SATURDAY.
ANOTHER WEAK COLD FRONT WILL PUSH IN FROM THE NORTH SUNDAY NIGHT AND
MOVE SOUTH THROUGH MONDAY. THE FRONTAL BOUNDARY STALLS TO THE SOUTH
OF THE FORECAST AREA THROUGH THE MIDDLE OF NEXT WEEK...KEEPING THE
PATTERN UNSETTLED WITH THUNDERSTORM CHANCES EACH AFTERNOON.
&&
.NEAR TERM /THROUGH FRIDAY/...
AS OF 455 PM...AREA RADARS CONTINUE TO INDICATE A BROKEN LINE OF
SHRA/TSRA ACROSS THE PIEDMONT...EAST OF I-85. THE ACTIVITY SHOULD
TRACK EAST...GENERALLY EXITING THE FORECAST AREA IN TWO HOURS. I
WILL UPDATE THE FORECAST TO INCREASE POPS AND QPF ALONG AND AHEAD OF
THE LINE AND DECREASE THEM BEHIND THE LINE. BY MID
EVENING...CONDITIONS ACROSS THE CWA SHOULD BE QUIET...WITH LINGERING
ISO SHRAS. I WILL ALSO UPDATE THE TEMP/DWPTS TO ALIGN WITH OBS.
AS OF 230 PM...CONVECTION HAS BEGUN TO FIRE ALONG THE BLUE RIDGE AND
NOW PROPAGATING OUT ONTO THE PIEDMONT FROM THE STATESVILLE AREA SW
TO THE SC MTNS. A FEW STORMS HAVE ALREADY BECOME SEVERE...PRODUCING
HAIL LARGER THAN 1" DIAMETER AND DAMAGING WINDS. GIVEN THE SPC
MESOANALYSIS PAGE SHOWING SBCAPE OF 2500-3000 J/KG...DCAPE AROUND
1000 J/KG...AND EFFECTIVE SHEAR OF 25-30KTS AHEAD OF THIS BROKEN
LINE...EXPECT THE TRENDS TO CONTINUE ACRS THE UPSTATE AND SWRN NC
PIEDMONT THRU THE REST OF THE AFTN. WILL UPDATE POPS TO LIKELY ALONG
AND SE OF THE CURRENT LINE POSITION.
TONIGHT...WITH SHORTWAVE TROF PASSING TO THE EAST...EXPECT
CONVECTION TO WANE FAIRLY QUICKLY EARLY THIS EVENING. HAVE POPS DOWN
TO SILENT BY MIDNIGHT ACRS THE ENTIRE CWFA. THERE WILL BE LINGERING
LLVL MOISTURE AND A SLOW-MOVING FNTL BNDRY SAGGING SEWD THRU THE
CWFA OVERNIGHT. SO PROBABLY WILL SEE PATCHY TO AREAS OF FOG AND
STRATUS BY DAYBREAK...ESP IN THE MTN VLYS. TEMPS WILL BE NEAR
NORMAL...MAINLY IN THE 60S.
FRIDAY...MODELS IN DECENT AGREEMENT ON THE COLD FRONT PUSHING ALL
THE WAY THRU THE CWFA TO THE SE BY MID MORNING. ALOFT...SUBSIDENCE
IN WAKE OF SHORTWAVE PASSAGE WILL WARM MID LVL TEMPS. FCST SNDGS
ACRS THE CWFA ARE CAPPED IN THE MID LVLS. CANNOT RULE OUT A STRAY
SHWR OR TWO IN THE SRN/CENTRAL NC MTNS...IF DEWPTS DON/T MIX OUT
ENUF. BUT NOT ENUF TO WARRANT ANY MENTION IN THE GRIDS. SO A DRY
FCST. WITH DECENT SUNSHINE...EXPECT NEAR NORMAL MAX TEMPS.
&&
.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY/...
AS OF 230 PM EDT THURSDAY...THE OVERALL UPPER PATTERN REMAINS IN
PLACE ACROSS THE REGION THROUGH THE SHORT RANGE...WITH AN UPPER
LOW/TROF OVER THE NORTHEAST AND A RIDGE AXIS OVER THE ROCKIES...
KEEPING A NW FLOW OVERHEAD. THE PERIOD BEGINS WITH DRY WEATHER
OVERNIGHT ON FRIDAY NIGHT...WHICH CONTINUES INTO SATURDAY MORNING.
THERE IS VERY LITTLE IN THE GUIDANCE TO SUGGEST MUCH IN THE WAY OF
CONVECTIVE PRECIP ON SATURDAY AFTERNOON AND THE GFS CONTINUES TO BE
DRY. HOWEVER...THE NAM DEVELOPS SOME CONVECTION OVER THE MOUNTAINS
AND IT IS HARD TO KEEP THAT FROM HAPPENING ON A TYPICAL DAY...SO NOT
MUCH WAS CHANGED FROM THE EARLIER FORECAST. A SHORT WAVE DROPPING
DOWN INTO THE EASTERN UPPER TROF SATURDAY NIGHT AND SUNDAY MORNING
WILL PROVIDE FOR A BETTER SITUATION CONVECTIVELY. THE MODELS SUGGEST
A FRONT DROPPING DOWN FROM THE NW EARLY SUNDAY...PERHAPS CROSSING
THE FCST AREA TOO EARLY IN THE DAY TO TRIGGER MUCH CONVECTION. WILL
MAINTAIN A CHANCE POP ON THE TN BORDER OVERNIGHT SATURDAY AND INTO
SUNDAY MORNING...WITH THE CHANCE OF UPSTREAM CONVECTION ALONG THE
FRONT REACHING THE FCST AREA BEFORE IT WEAKENS. A CHANCE POP WAS
ALSO KEPT THROUGH SUNDAY AFTERNOON IN THE EVENT THAT THE FRONT DOES
NOT MAKE AS MUCH SOUTHWARD PROGRESS AS SHOWN BY THE GFS. TEMPS WERE
KEPT NEAR A BLEND OF THE GUIDANCE.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
AS OF 200 PM THURSDAY...THE EXTENDED RANGE BEGINS JUST AFTER THE
PASSAGE OF A WEAK FRONTAL BOUNDARY DURING THE DAY ON SUNDAY. HIGH
PRESSURE QUICKLY BUILDS IN OVER THE MIDWEST...AND THE FRONT STALLS
RIGHT ALONG THE PERIPHERY OF THE HIGH JUST TO THE SOUTH OF THE CWA
FOLLOWING AN UPPER LEVEL TROUGH. MODELS DIVERGE GREATLY ON PLACEMENT
OF THE FRONT AND STRENGTH OF THE HIGH...SO KEEP CHANCE POPS IN ON
SUNDAY AFTERNOON AND MONDAY. THE POSITION OF THE FRONT WILL KEEP THE
PATTERN UNSETTLED...WITH MULTIPLE WEAK SHORTWAVES EXPECTED TO CROSS
THE CWA THROUGH MID-WEEK. AN UPPER LEVEL LOW APPROACHES THE CWA BY
LATE NEXT WEEK...AGAIN BRINGING WITH IT THE POSSIBILITY OF HEAVY
RAIN AND THUNDERSTORMS. MODELS STILL DIVERGE GREATLY ON SYNOPTIC
PATTERN AND TIMING OF FEATURES THROUGH THE END OF THE PERIOD
HOWEVER...SO KEPT POPS NEAR CLIMO EACH DAY FOLLOWING A MAINLY
DIURNAL TREND. HIGH TEMPS WILL REMAIN A DEGREE OR TWO BELOW
AVERAGE...WITH LOWS RIGHT AROUND NORMAL.
&&
.AVIATION /21Z THURSDAY THROUGH TUESDAY/...
AT KCLT...A BROKEN LINE OF CONVECTION IS DEVELOPING NW OF THE
TERMINAL AT TIME OF TAF ISSUANCE. WITH PLENTY OF INSTBY AND JUST
ENUF SHEAR...EXPECT THE LINE TO AFFECT THE TERMINAL WITHIN THE NEXT
COUPLE HOURS. THE LATEST HRRR SHOWS SEVERAL CLUSTERS OF STORMS ACRS
THE NC PIEDMONT THRU AT LEAST 00Z THIS EVENING. SO WILL GO WITH A
TEMPO FIRST TWO HOURS...THEN PREVAILING TSRA THRU 00Z.
THEREAFTER...A COLD FRONT WILL PUSH THRU AND BRING THE WINDS AROUND
TO NE. GUIDANCE MIXED ON WHETHER ANY FOG OR STRATUS WILL BE ABLE TO
DEVELOP. IF WIDESPREAD RAIN FALLS ACRS THE REGION...MAY SEE MORE
RESTRICTIONS. WILL GO WITH JUST MVFR VSBY TOWARD DAYBREAK. VFR
CONDITIONS AND LGT NELY WINDS FRIDAY MORNING THRU 18Z.
ELSEWHERE...CONVECTION HAS CLEARED THRU KAVL AND KHKY...BUT
ADDITIONAL SCATTERED SHRA/TSRA ARE EXPECTED TO DEVELOP THRU THE
AFTN. SO WILL KEEP VCTS IN FOR REST OF THE AFTN. THE UPSTATE TAF
SITES ARE A BIT MORE UNCERTAIN. THE HRRR HAS A LINE OF STORMS BACK
BUILD AT LEAST TO KGMU/KGSP. NOT CONFIDENT ENUF TO GO WITH
TEMPO...SO KEEPING JUST VCTS. KAND LOOKS TO HAVE THE LOWEST CHC OF
TSRA...BUT STILL HIGH ENUF FOR VCTS. CONVECTION SHUD WANE QUICKLY
AFTER SUNSET. GUIDANCE MIXED ON HOW MUCH RESTRICTIONS ACRS THE
REGION...BUT GIVEN THE MOIST GROUND...LIGHT WIND...AND DRY MID
LVLS...EXPECT AT LEAST PATCHY FOG AND STRATUS OVERNIGHT...ESP IN THE
MTN VLYS. VFR CONDITIONS EXPECTED AFTER DAYBREAK THRU THE REST OF
THE TAF PERIOD.
OUTLOOK...EXPECT CONDITIONS TO IMPROVE FOR THE WEEKEND AS HIGH
PRESSURE BUILDS IN BEHIND COLD FRONT. WET CONDITIONS WILL RETURN
FOR THE START OF NEXT WEEK ASSOCIATED WITH ANOTHER FRONTAL PASSAGE.
CONFIDENCE TABLE...
21-03Z 03-09Z 09-15Z 15-21Z
KCLT MED 79% HIGH 91% HIGH 100% HIGH 100%
KGSP HIGH 100% HIGH 91% HIGH 100% HIGH 100%
KAVL HIGH 100% HIGH 88% HIGH 80% MED 65%
KHKY HIGH 100% HIGH 100% HIGH 95% HIGH 100%
KGMU HIGH 100% HIGH 91% HIGH 100% HIGH 100%
KAND HIGH 100% HIGH 92% 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...NED
SHORT TERM...PM
LONG TERM...VISIN
AVIATION...ARK
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
238 PM EDT THU AUG 1 2013
.SYNOPSIS...
A WEAK COLD FRONT WILL CROSS THE REGION TODAY...BEFORE HIGH PRESSURE
BUILDS IN FROM THE NORTHWEST FRIDAY AND LINGERS INTO SATURDAY.
ANOTHER WEAK COLD FRONT WILL PUSH IN FROM THE NORTH SUNDAY NIGHT AND
MOVE SOUTH THROUGH MONDAY. THE FRONTAL BOUNDARY STALLS TO THE SOUTH
OF THE FORECAST AREA THROUGH THE MIDDLE OF NEXT WEEK...KEEPING THE
PATTERN UNSETTLED WITH THUNDERSTORM CHANCES EACH AFTERNOON.
&&
.NEAR TERM /THROUGH FRIDAY/...
AS OF 230 PM...CONVECTION HAS BEGUN TO FIRE ALONG THE BLUE RIDGE AND
NOW PROPAGATING OUT ONTO THE PIEDMONT FROM THE STATESVILLE AREA SW
TO THE SC MTNS. A FEW STORMS HAVE ALREADY BECOME SEVERE...PRODUCING
HAIL LARGER THAN 1" DIAMETER AND DAMAGING WINDS. GIVEN THE SPC
MESOANALYSIS PAGE SHOWING SBCAPE OF 2500-3000 J/KG...DCAPE AROUND
1000 J/KG...AND EFFECTIVE SHEAR OF 25-30KTS AHEAD OF THIS BROKEN
LINE...EXPECT THE TRENDS TO CONTINUE ACRS THE UPSTATE AND SWRN NC
PIEDMONT THRU THE REST OF THE AFTN. WILL UPDATE POPS TO LIKELY ALONG
AND SE OF THE CURRENT LINE POSITION.
TONIGHT...WITH SHORTWAVE TROF PASSING TO THE EAST...EXPECT
CONVECTION TO WANE FAIRLY QUICKLY EARLY THIS EVENING. HAVE POPS DOWN
TO SILENT BY MIDNIGHT ACRS THE ENTIRE CWFA. THERE WILL BE LINGERING
LLVL MOISTURE AND A SLOW-MOVING FNTL BNDRY SAGGING SEWD THRU THE
CWFA OVERNIGHT. SO PROBABLY WILL SEE PATCHY TO AREAS OF FOG AND
STRATUS BY DAYBREAK...ESP IN THE MTN VLYS. TEMPS WILL BE NEAR
NORMAL...MAINLY IN THE 60S.
FRIDAY...MODELS IN DECENT AGREEMENT ON THE COLD FRONT PUSHING ALL
THE WAY THRU THE CWFA TO THE SE BY MID MORNING. ALOFT...SUBSIDENCE
IN WAKE OF SHORTWAVE PASSAGE WILL WARM MID LVL TEMPS. FCST SNDGS
ACRS THE CWFA ARE CAPPED IN THE MID LVLS. CANNOT RULE OUT A STRAY
SHWR OR TWO IN THE SRN/CENTRAL NC MTNS...IF DEWPTS DON/T MIX OUT
ENUF. BUT NOT ENUF TO WARRANT ANY MENTION IN THE GRIDS. SO A DRY
FCST. WITH DECENT SUNSHINE...EXPECT NEAR NORMAL MAX TEMPS.
&&
.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY/...
AS OF 230 PM EDT THURSDAY...THE OVERALL UPPER PATTERN REMAINS IN
PLACE ACROSS THE REGION THROUGH THE SHORT RANGE...WITH AN UPPER
LOW/TROF OVER THE NORTHEAST AND A RIDGE AXIS OVER THE ROCKIES...
KEEPING A NW FLOW OVERHEAD. THE PERIOD BEGINS WITH DRY WEATHER
OVERNIGHT ON FRIDAY NIGHT...WHICH CONTINUES INTO SATURDAY MORNING.
THERE IS VERY LITTLE IN THE GUIDANCE TO SUGGEST MUCH IN THE WAY OF
CONVECTIVE PRECIP ON SATURDAY AFTERNOON AND THE GFS CONTINUES TO BE
DRY. HOWEVER...THE NAM DEVELOPS SOME CONVECTION OVER THE MOUNTAINS
AND IT IS HARD TO KEEP THAT FROM HAPPENING ON A TYPICAL DAY...SO NOT
MUCH WAS CHANGED FROM THE EARLIER FORECAST. A SHORT WAVE DROPPING
DOWN INTO THE EASTERN UPPER TROF SATURDAY NIGHT AND SUNDAY MORNING
WILL PROVIDE FOR A BETTER SITUATION CONVECTIVELY. THE MODELS SUGGEST
A FRONT DROPPING DOWN FROM THE NW EARLY SUNDAY...PERHAPS CROSSING
THE FCST AREA TOO EARLY IN THE DAY TO TRIGGER MUCH CONVECTION. WILL
MAINTAIN A CHANCE POP ON THE TN BORDER OVERNIGHT SATURDAY AND INTO
SUNDAY MORNING...WITH THE CHANCE OF UPSTREAM CONVECTION ALONG THE
FRONT REACHING THE FCST AREA BEFORE IT WEAKENS. A CHANCE POP WAS
ALSO KEPT THROUGH SUNDAY AFTERNOON IN THE EVENT THAT THE FRONT DOES
NOT MAKE AS MUCH SOUTHWARD PROGRESS AS SHOWN BY THE GFS. TEMPS WERE
KEPT NEAR A BLEND OF THE GUIDANCE.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
AS OF 200 PM THURSDAY...THE EXTENDED RANGE BEGINS JUST AFTER THE
PASSAGE OF A WEAK FRONTAL BOUNDARY DURING THE DAY ON SUNDAY. HIGH
PRESSURE QUICKLY BUILDS IN OVER THE MIDWEST...AND THE FRONT STALLS
RIGHT ALONG THE PERIPHERY OF THE HIGH JUST TO THE SOUTH OF THE CWA
FOLLOWING AN UPPER LEVEL TROUGH. MODELS DIVERGE GREATLY ON PLACEMENT
OF THE FRONT AND STRENGTH OF THE HIGH...SO KEEP CHANCE POPS IN ON
SUNDAY AFTERNOON AND MONDAY. THE POSITION OF THE FRONT WILL KEEP THE
PATTERN UNSETTLED...WITH MULTIPLE WEAK SHORTWAVES EXPECTED TO CROSS
THE CWA THROUGH MID-WEEK. AN UPPER LEVEL LOW APPROACHES THE CWA BY
LATE NEXT WEEK...AGAIN BRINGING WITH IT THE POSSIBILITY OF HEAVY
RAIN AND THUNDERSTORMS. MODELS STILL DIVERGE GREATLY ON SYNOPTIC
PATTERN AND TIMING OF FEATURES THROUGH THE END OF THE PERIOD
HOWEVER...SO KEPT POPS NEAR CLIMO EACH DAY FOLLOWING A MAINLY
DIURNAL TREND. HIGH TEMPS WILL REMAIN A DEGREE OR TWO BELOW
AVERAGE...WITH LOWS RIGHT AROUND NORMAL.
&&
.AVIATION /19Z THURSDAY THROUGH TUESDAY/...
AT KCLT...A BROKEN LINE OF CONVECTION IS DEVELOPING NW OF THE
TERMINAL AT TIME OF TAF ISSUANCE. WITH PLENTY OF INSTBY AND JUST
ENUF SHEAR...EXPECT THE LINE TO AFFECT THE TERMINAL WITHIN THE NEXT
COUPLE HOURS. THE LATEST HRRR SHOWS SEVERAL CLUSTERS OF STORMS ACRS
THE NC PIEDMONT THRU AT LEAST 00Z THIS EVENING. SO WILL GO WITH A
TEMPO FIRST TWO HOURS...THEN PREVAILING TSRA THRU 00Z.
THEREAFTER...A COLD FRONT WILL PUSH THRU AND BRING THE WINDS AROUND
TO NE. GUIDANCE MIXED ON WHETHER ANY FOG OR STRATUS WILL BE ABLE TO
DEVELOP. IF WIDESPREAD RAIN FALLS ACRS THE REGION...MAY SEE MORE
RESTRICTIONS. WILL GO WITH JUST MVFR VSBY TOWARD DAYBREAK. VFR
CONDITIONS AND LGT NELY WINDS FRIDAY MORNING THRU 18Z.
ELSEWHERE...CONVECTION HAS CLEARED THRU KAVL AND KHKY...BUT
ADDITIONAL SCATTERED SHRA/TSRA ARE EXPECTED TO DEVELOP THRU THE
AFTN. SO WILL KEEP VCTS IN FOR REST OF THE AFTN. THE UPSTATE TAF
SITES ARE A BIT MORE UNCERTAIN. THE HRRR HAS A LINE OF STORMS BACK
BUILD AT LEAST TO KGMU/KGSP. NOT CONFIDENT ENUF TO GO WITH
TEMPO...SO KEEPING JUST VCTS. KAND LOOKS TO HAVE THE LOWEST CHC OF
TSRA...BUT STILL HIGH ENUF FOR VCTS. CONVECTION SHUD WANE QUICKLY
AFTER SUNSET. GUIDANCE MIXED ON HOW MUCH RESTRICTIONS ACRS THE
REGION...BUT GIVEN THE MOIST GROUND...LIGHT WIND...AND DRY MID
LVLS...EXPECT AT LEAST PATCHY FOG AND STRATUS OVERNIGHT...ESP IN THE
MTN VLYS. VFR CONDITIONS EXPECTED AFTER DAYBREAK THRU THE REST OF
THE TAF PERIOD.
OUTLOOK...EXPECT CONDITIONS TO IMPROVE FOR THE WEEKEND AS HIGH
PRESSURE BUILDS IN BEHIND COLD FRONT. WET CONDITIONS WILL RETURN
FOR THE START OF NEXT WEEK ASSOCIATED WITH ANOTHER FRONTAL PASSAGE.
CONFIDENCE TABLE...
17-23Z 23-05Z 05-11Z 11-17Z
KCLT HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KGSP HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAVL HIGH 93% HIGH 100% HIGH 91% HIGH 91%
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...ARK
SHORT TERM...PM
LONG TERM...VISIN
AVIATION...ARK
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
209 PM EDT THU AUG 1 2013
.SYNOPSIS...
A WEAK COLD FRONT WILL CROSS THE REGION TODAY...BEFORE HIGH PRESSURE
BUILDS IN FROM THE NORTHWEST FRIDAY AND LINGERS INTO SATURDAY.
ANOTHER WEAK COLD FRONT WILL PUSH IN FROM THE NORTH SUNDAY NIGHT AND
MOVE SOUTH THROUGH MONDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1000 AM...STRATUS IS GRADUALLY ERODING WITH DAYTIME HEATING
AND SOME DOWNSLOPE NWLY FLOW ATOP THE CLOUD LAYER. MEANWHILE...SOME
MID AND HIGH CLOUDS CONTINUE TO STREAM ACRS THE CWFA...AS AN UPR
SHORTWAVE TROF ENTERS FROM THE WEST. SO EXPECTING A MIX OF SUN AND
CLOUDS INTO EARLY AFTN. FROM THERE...FCST SNDGS INDICATE WE SHUD
DESTABILIZE TO 2000-2500 J/KG OF SBCAPE BY PEAK HEATING...ESP ALONG
THE BLUE RIDGE AND EAST. THERE SHUD BE DECENT LLVL CONVERGENCE ALONG
THE ERN SLOPES AND A LEE TROF ACRS THE PIEDMONT...KEEPING PWATS IN
THE 1.25-1.5" RANGE. SO I THINK THERE SHUD BE DECENT COVERAGE OF
SHWRS AND TSTMS ACRS THE ERN HALF OF THE CWFA. THIS IS IN LINE WITH
THE PREVIOUS FCST...SO ONLY MINOR TWEAKS TO THE POP GRIDS WERE MADE.
SOME DRY MID LVL AIR AND EFFECTIVE SHEAR OF 30-35 KTS ATOP THE MOIST
BL SHUD RESULT IN A BETTER MICROBURST THREAT WITH THE STRONGEST
CONVECTION THIS AFTN...ESP AREAS EAST OF I-85...WHERE THE BEST
INSTBY WILL BE. FREEZING LVLS ARE AROUND 14 KFT ON THE MRNG
SNDGS...SO A FIRST GUESS CORE HEIGHT (55 DBZ)IS AROUND 25.5 KFT.
TONIGHT...FRONT MAKES ITS WAY ACROSS THE CWFA WITH LOWER LLVL THETA-E
ADVECTING IN ON NWLY WINDS. POPS WILL DIMINISH TO UNMENTIONABLY LOW
VALUES BY EVENING AND SKIES WILL BECOME MOSTLY CLEAR. SFC DEWPOINTS
DON/T DROP OFF ALL THAT MUCH SO LOW TEMPS REMAIN NEAR NORMAL PIEDMONT
AND A COUPLE DEGREES BELOW NORMAL MTNS/FOOTHILLS.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 230 AM EDT THU...THE UPPER PATTERN SHOWS AN INFLUX OF H7-H5
DNVA AND FLAT RIDGING ENCOMPASSING THE AREA FRI IN SUPPORT OF A
SMALL SCALE SFC HIGH. THIS WILL BE ENOUGH TO OFFSET ANY CONVECTIVE
CHANCES AS RISING SFC PARCELS ARE SUPPRESSED BY WARM AIR ALOFT. THUS
WITH NO TRIGGERS IN THE AREA...WILL COUNT ON A DRY DAY WITH MAX
TEMPS AROUND NORMAL OR A DEGREE OR TWO ABOVE.
THE SFC HIGH BEGINS TO BREAK DOWN SAT AS UPPER HEIGHTS DROP AND
INCOMING POCKETS OF S/W ENERGY TRAVERSE THE CWFA. THE 00Z NAM IS
MORE DEFINITIVE IN A COUPLED S/W CROSSING AROUND 18Z WITH THE 00Z
GFS ON BOARD TO SOME DEGREE. THE BEST LLVL MOISTURE FLUX WILL REMAIN
SHUNTED TO THE WEST...YET SOUNDINGS INDICATE ENOUGH MLVL COOLING TO
ALLOW SOME AFTERNOON ELCAPE ACROSS MOST AREAS. WITH MECH LIFT
CONTINUING WEST...THERE WILL BE AN INCREASING CHANCE OF SHRA/TSTMS
ACROSS THE MTNS AND THE REST OF THE CWFA BY THE AFTERNOON...ENOUGH
SO TO INTRODUCE NEAR CLIMO POPS. MAX TEMPS WILL BE TRICKY DEPENDING
ON THE OVERALL CLOUDINESS...BUT LLVL THICKNESSES AND MOS SUPPORT
L90S NON/MTNS AND THE GRIDS HAVE BEEN ADJ IN THIS DIRECTION.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
AS OF 305 AM EDT THU...THE EXT RANGE LOOKS TO REMAIN ACTIVE AS THE
UPPER FLOW BRINGS IN ROUNDS OF S/W ENERGY AROUND A LARGE OCCLUDED
CANADIAN SYSTEM. THE MODELS ARE HANDLING THE ERN CONUS SYNOPTIC
PATTERN DIFFERENTLY AND THE TIMING OF TWO ILL DEFINED SFC FRONTS OR
TROFS OF LOW PRESSURE EXPECTED TO AFFECT THE CWFA SUN THOUGH THE
PERIOD.
FOR NOW...WILL COUNT ON THE FIRST FRONT TO DEVELOP IN RESPONSE TO
RATHER STRONG HIGH PRESSURE MOVING SOUTH OUT OF CANADA SUN. THERE IS
A DEFINED N/S INSTABILITY GRADIENT ASSOCIATED WITH THIS FEATURE AND
THUNDER CHANCES WILL BE LIMITED TO THE SRN HALF OF THE CWFA SUN
NIGHT THROUGH MON. EXPECT THIS FRONT TO STALL OUT JUST TO THE
SOUTH...WHILE ANOTHER SFC BOUNDARY FORMS ACROSS THE OH VALLEY MON
NIGHT AND PUSHES INTO THE AREA DURING THE DAY TUE. THERE ISNT MUCH
UPPER SUPPORT WITH EITHER OF THESE FRONTS...PRETTY MUCH BACK DOOR
FRONTS...BUT DEEP CONVECTION PRODUCING STRONG TO SEVERE STORMS ARE
POSSIBLE EACH AFTERNOON MON AND TUE. THERE MAY ALSO BE A HYDRO
CONCERN WITH THE BOUNDARIES MERGING AND PERHAPS STALLING OVER THE
AREA. HOWEVER...ITS TOO EARLY TO TELL WHAT THE DEGREE OF THIS THREAT
WILL BE ATTM. WED COULD DRY OUT IN A RELATIVE SENSE WITH THE MODELS
DIVERGING A SUPPRESSIVE SFC HIGH SCENARIO. MAX TEMPS WILL GENERALLY
BE HELD A COUPLE DEGREES BELOW NORMAL THROUGH THE PERIOD...WITH MINS
AROUND NORMAL.
&&
.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
AT KCLT...A BROKEN LINE OF CONVECTION IS DEVELOPING NW OF THE
TERMINAL AT TIME OF TAF ISSUANCE. WITH PLENTY OF INSTBY AND JUST
ENUF SHEAR...EXPECT THE LINE TO AFFECT THE TERMINAL WITHIN THE NEXT
COUPLE HOURS. THE LATEST HRRR SHOWS SEVERAL CLUSTERS OF STORMS ACRS
THE NC PIEDMONT THRU AT LEAST 00Z THIS EVENING. SO WILL GO WITH A
TEMPO FIRST TWO HOURS...THEN PREVAILING TSRA THRU 00Z.
THEREAFTER...A COLD FRONT WILL PUSH THRU AND BRING THE WINDS AROUND
TO NE. GUIDANCE MIXED ON WHETHER ANY FOG OR STRATUS WILL BE ABLE TO
DEVELOP. IF WIDESPREAD RAIN FALLS ACRS THE REGION...MAY SEE MORE
RESTRICTIONS. WILL GO WITH JUST MVFR VSBY TOWARD DAYBREAK. VFR
CONDITIONS AND LGT NELY WINDS FRIDAY MORNING THRU 18Z.
ELSEWHERE...CONVECTION HAS CLEARED THRU KAVL AND KHKY...BUT
ADDITIONAL SCATTERED SHRA/TSRA ARE EXPECTED TO DEVELOP THRU THE
AFTN. SO WILL KEEP VCTS IN FOR REST OF THE AFTN. THE UPSTATE TAF
SITES ARE A BIT MORE UNCERTAIN. THE HRRR HAS A LINE OF STORMS BACK
BUILD AT LEAST TO KGMU/KGSP. NOT CONFIDENT ENUF TO GO WITH
TEMPO...SO KEEPING JUST VCTS. KAND LOOKS TO HAVE THE LOWEST CHC OF
TSRA...BUT STILL HIGH ENUF FOR VCTS. CONVECTION SHUD WANE QUICKLY
AFTER SUNSET. GUIDANCE MIXED ON HOW MUCH RESTRICTIONS ACRS THE
REGION...BUT GIVEN THE MOIST GROUND...LIGHT WIND...AND DRY MID
LVLS...EXPECT AT LEAST PATCHY FOG AND STRATUS OVERNIGHT...ESP IN THE
MTN VLYS. VFR CONDITIONS EXPECTED AFTER DAYBREAK THRU THE REST OF
THE TAF PERIOD.
OUTLOOK...EXPECT CONDITIONS TO IMPROVE FOR THE WEEKEND AS HIGH
PRESSURE BUILDS IN BEHIND COLD FRONT. WET CONDITIONS WILL RETURN
FOR THE START OF NEXT WEEK ASSOCIATED WITH ANOTHER FRONTAL PASSAGE.
CONFIDENCE TABLE...
17-23Z 23-05Z 05-11Z 11-17Z
KCLT HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KGSP HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAVL HIGH 93% HIGH 100% HIGH 91% HIGH 91%
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...SBK
NEAR TERM...ARK/WIMBERLEY
SHORT TERM...SBK
LONG TERM...SBK
AVIATION...ARK
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
1059 PM CDT FRI AUG 2 2013
.UPDATE...
ISSUED AT 1025 PM CDT FRI AUG 2 2013
PRECIPITATION ENDED QUICKLY OVER THE AREA LATE THIS AFTERNOON.
SKIES HAVE CLEARED PRETTY WELL WITH LOW CLOUDS LEFT ON THE SOUTH
SIDE OF THE MISSOURI RIVER. MOST OF THESE CLOUDS SHOULD CLEAR OUT
SLOWLY TO THE SOUTHWEST THE REST OF TONIGHT BUT THEY MAY STAY
PRETTY CLOSE THOUGH MAY KEEP SOME CLOUDS HUGGING THE RIVER SW.
MOSTLY CLEAR SKIES SHOULD BE THE RULE THOUGH TONIGHT. AT THIS
TIME NOT EXPECTING ANY FOG IN SOMEWHAT DRIER AIR UNDER BUBBLE HIGH
BUT WILL HAVE TO WATCH FOR PATCHY RADIATION FOG...PROBABLY VERY
LOCAL...AS DECENT COOLING CONTINUED TO ASSERT ITSELF. HAD TO COOL
LOW TEMPERATURES 2 OR 3 DEGREES AS THE BETTER COOLING UNDER MOSTLY
CLEAR SKIES SHOULD BE A TREND.
&&
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 338 PM CDT FRI AUG 2 2013
MCV PRECIPITATION EXITING THE FAR SOUTHEASTERN CWA AT MID
AFTERNOON...AND MONITORING THE TRAILING EDGE OF NOW SLOWLY
DISSIPATING COMPLEX OF SHOWERS AND ISOLATED THUNDER ACROSS
SOUTHEASTERN SD. SUPPORT FOR LATTER PRECIP IS MID LEVEL LIFT FORCING
WITH WAVE MOVING THROUGH NORTHEAST AND TAILING TOWARD CENTRAL SD.
FEATURE KEEPS CLIPPING ALONG LATE AFTERNOON AND INDICATION ON WATER
VAPOR LOOP FOR SLIGHTLY RISING HEIGHTS IN WHAT HAS BEEN A GRADUALLY
STABILIZED OVERALL AIRMASS AS PRECIPITATION HAS WORKED THROUGH. MID
LEVEL BOUNDARY REMAINS INTO THE NIGHT RIGHT ACROSS THE AREA...BUT
CANNOT REALLY FIND ANY DISTINCT FEATURE TO THINK IT WILL ACTIVATE
BEHIND FEATURE THIS AFTERNOON FOR QUITE SOME TIME. THEREFORE...
HAVE CUT BACK POPS FAIRLY QUICKLY FROM WEST TO EAST THROUGH THE
REMAINDER OF THE AFTERNOON. WHILE HRRR HAS HAD A PRETTY GOOD IDEA TO
EVOLUTION OF PRECIP TODAY...ITS TIMING HAS LEFT QUITE A BIT TO BE
DESIRED...AND LIKELY CONTINUES TOO SLOW OVERALL. RETAINED ISOLATED
THUNDER MENTION MAINLY THROUGH THE MISSOURI CORRIDOR EASTWARD
THROUGH NORTHWEST IOWA...AS WILL STILL HAVE A BIT OF ELEVATED
INSTABILITY TO WORK THROUGH...AND WOULD BE PRUDENT TO KEEP AN EYE TO
THE SOUTHERN END OF THE LINE AS MAY YET PULSE UP IN STRENGTH A BIT
AND PRODUCE A LITTLE HAIL. MUCH OF THE REMAINDER OF THE NIGHT SHOULD
REMAIN QUIET...WITH PARTLY TO MOSTLY CLOUDY SKIES AFTER PERHAPS A
SHORT PERIOD OF POST CONVECTIVE CLEARING.
LATER TONIGHT INTO EARLY SATURDAY...ANOTHER WAVE MOVING THROUGH THE
ROCKIES WILL LIKELY INITIATE NOCTURNAL DEVELOPMENT THROUGH THE HIGH
PLAINS. PROPAGATION OF COMPLEX SHOULD KEEP MOSTLY CLEAR OF THE
AREA...BUT POTENTIAL FOR SOMETHING DEVELOPING INITIALLY NORTH OF THE
BLACK HILLS TO CLIP THE FAR SOUTHWEST. EASTERN LOCATIONS WILL BE
PROTECTED OF SORTS BY RIDGE OF HIGH PRESSURE AND SOMEWHAT DRIER
NORTHEAST TO EAST LOW LEVEL FLOW. SHOULD BE FAIRLY OPEN TO MIX
TOWARD 850-800 HPA ON SATURDAY WHICH WOULD YIELD AN ABUNDANCE OF MID
70S TO NEAR 80 ACROSS THE AREA.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 338 PM CDT FRI AUG 2 2013
FAIRLY ACTIVE WEATHER PATTERN CONTINUES FOR THE BULK OF NEXT WEEK
WITH SEVERAL WAVE DROPPING ACROSS THE NORTHERN PLAINS ALONG THE
NORTHWESTERLY UPPER LEVEL FLOW. OVERALL TEMPERATURE TRENDS REMAIN
BELOW NORMAL WITH ONLY MINOR WARMING TRENDS BACK INTO THE LOW AND
MID 80S...FOLLOWED BY COOLING INTO THE 70S BEHIND THE BOUNDARIES.
MID LEVEL BOUNDARY IS EXPECTED TO SET UP ACROSS WESTERN SOUTH DAKOTA
AND NEAR THE MISSOURI VALLEY SATURDAY EVENING. SOME SCATTERED TO
ISOLATED THUNDERSTORMS ARE EXPECTED TO FIRE TO THE WEST OF THE
FORECAST AREA BY AFTERNOON AND COULD DRIFT INTO OUR FAR WESTERN
COUNTIES IN THE EVENING AND OVERNIGHT. MODELS TRACK A MID LEVEL INTO
THE NORTHERN HIGH PLAINS ON SUNDAY AND THROUGH THE FORECAST AREA
SUNDAY NIGHT. WITH SOME WEAK INSTABILITY EXTENDING INTO SOUTH
CENTRAL SOUTH DAKOTA...SCATTERED CONVECTION WILL AGAIN INITIATE
ACROSS OUR WESTERN COUNTIES SUNDAY AFTERNOON AND TRACK ACROSS THE
REMAINDER OF THE FORECAST AREA OVERNIGHT.
MODELS A BIT MORE UNCERTAIN WITH THE TIMING OF WAVES IN THE
EXTENDED. THE GFS BRINGS ANOTHER DECENT SHORTWAVE THROUGH THE
FORECAST AREA MONDAY NIGHT...WHILE THE ECMWF AND GEM ARE MORE
SUBTLE. BETTER AGREEMENT IS SEEN TUESDAY NIGHT WITH A WAVE AND COLD
FRONT DROPPING THROUGH THE REGION. THIS SHOULD ALLOW A COOLER AND
DRIER PUSH TO BRING A BREAK TO THE ACTIVE WEATHER PATTERN WEDNESDAY
THROUGH FRIDAY. DID SCALE BACK ON THE SPOTTY PRECIPITATION CHANCES
GIVEN BY THE ALLBLEND IN THE EXTENDED WITH THE EXCEPTION OF SOUTH
CENTRAL SD WHICH COULD SEE SOME HIGH PLAINS CONVECTION DRIFT INTO
THE AREA.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1059 PM CDT FRI AUG 2 2013
VFR CONDITIONS EXPECTED THROUGH THE PERIOD. MAY SEE PATCHY MVFR FOG
DEVELOPMENT WITH GOOD RADIATIONAL COOLING WITH SURFACE RIDGE OVER
AREAS WHICH RECEIVED MODEST RAINFALL ON FRIDAY. HOWEVER CONFIDENCE
LOW THAT THIS WILL OCCUR...ESPECIALLY AT SPECIFIC TAF LOCATIONS...
AND WILL HAVE VFR CONDITIONS IN THE TAFS THROUGH THE PERIOD FOR NOW.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
UPDATE...
SHORT TERM...CHAPMAN
LONG TERM...
AVIATION...JH
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
1025 PM CDT FRI AUG 2 2013
.UPDATE...
ISSUED AT 1025 PM CDT FRI AUG 2 2013
PRECIPITATION ENDED QUICKLY OVER THE AREA LATE THIS AFTERNOON.
SKIES HAVE CLEARED PRETTY WELL WITH LOW CLOUDS LEFT ON THE SOUTH
SIDE OF THE MISSOURI RIVER. MOST OF THESE CLOUDS SHOULD CLEAR OUT
SLOWLY TO THE SOUTHWEST THE REST OF TONIGHT BUT THEY MAY STAY
PRETTY CLOSE THOUGH MAY KEEP SOME CLOUDS HUGGING THE RIVER SW.
MOSTLY CLEAR SKIES SHOULD BE THE RULE THOUGH TONIGHT. AT THIS
TIME NOT EXPECTING ANY FOG IN SOMEWHAT DRIER AIR UNDER BUBBLE HIGH
BUT WILL HAVE TO WATCH FOR PATCHY RADIATION FOG...PROBABLY VERY
LOCAL...AS DECENT COOLING CONTINUED TO ASSERT ITSELF. HAD TO COOL
LOW TEMPERATURES 2 OR 3 DEGREES AS THE BETTER COOLING UNDER MOSTLY
CLEAR SKIES SHOULD BE A TREND.
&&
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 338 PM CDT FRI AUG 2 2013
MCV PRECIPITATION EXITING THE FAR SOUTHEASTERN CWA AT MID
AFTERNOON...AND MONITORING THE TRAILING EDGE OF NOW SLOWLY
DISSIPATING COMPLEX OF SHOWERS AND ISOLATED THUNDER ACROSS
SOUTHEASTERN SD. SUPPORT FOR LATTER PRECIP IS MID LEVEL LIFT FORCING
WITH WAVE MOVING THROUGH NORTHEAST AND TAILING TOWARD CENTRAL SD.
FEATURE KEEPS CLIPPING ALONG LATE AFTERNOON AND INDICATION ON WATER
VAPOR LOOP FOR SLIGHTLY RISING HEIGHTS IN WHAT HAS BEEN A GRADUALLY
STABILIZED OVERALL AIRMASS AS PRECIPITATION HAS WORKED THROUGH. MID
LEVEL BOUNDARY REMAINS INTO THE NIGHT RIGHT ACROSS THE AREA...BUT
CANNOT REALLY FIND ANY DISTINCT FEATURE TO THINK IT WILL ACTIVATE
BEHIND FEATURE THIS AFTERNOON FOR QUITE SOME TIME. THEREFORE...
HAVE CUT BACK POPS FAIRLY QUICKLY FROM WEST TO EAST THROUGH THE
REMAINDER OF THE AFTERNOON. WHILE HRRR HAS HAD A PRETTY GOOD IDEA TO
EVOLUTION OF PRECIP TODAY...ITS TIMING HAS LEFT QUITE A BIT TO BE
DESIRED...AND LIKELY CONTINUES TOO SLOW OVERALL. RETAINED ISOLATED
THUNDER MENTION MAINLY THROUGH THE MISSOURI CORRIDOR EASTWARD
THROUGH NORTHWEST IOWA...AS WILL STILL HAVE A BIT OF ELEVATED
INSTABILITY TO WORK THROUGH...AND WOULD BE PRUDENT TO KEEP AN EYE TO
THE SOUTHERN END OF THE LINE AS MAY YET PULSE UP IN STRENGTH A BIT
AND PRODUCE A LITTLE HAIL. MUCH OF THE REMAINDER OF THE NIGHT SHOULD
REMAIN QUIET...WITH PARTLY TO MOSTLY CLOUDY SKIES AFTER PERHAPS A
SHORT PERIOD OF POST CONVECTIVE CLEARING.
LATER TONIGHT INTO EARLY SATURDAY...ANOTHER WAVE MOVING THROUGH THE
ROCKIES WILL LIKELY INITIATE NOCTURNAL DEVELOPMENT THROUGH THE HIGH
PLAINS. PROPAGATION OF COMPLEX SHOULD KEEP MOSTLY CLEAR OF THE
AREA...BUT POTENTIAL FOR SOMETHING DEVELOPING INITIALLY NORTH OF THE
BLACK HILLS TO CLIP THE FAR SOUTHWEST. EASTERN LOCATIONS WILL BE
PROTECTED OF SORTS BY RIDGE OF HIGH PRESSURE AND SOMEWHAT DRIER
NORTHEAST TO EAST LOW LEVEL FLOW. SHOULD BE FAIRLY OPEN TO MIX
TOWARD 850-800 HPA ON SATURDAY WHICH WOULD YIELD AN ABUNDANCE OF MID
70S TO NEAR 80 ACROSS THE AREA.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 338 PM CDT FRI AUG 2 2013
FAIRLY ACTIVE WEATHER PATTERN CONTINUES FOR THE BULK OF NEXT WEEK
WITH SEVERAL WAVE DROPPING ACROSS THE NORTHERN PLAINS ALONG THE
NORTHWESTERLY UPPER LEVEL FLOW. OVERALL TEMPERATURE TRENDS REMAIN
BELOW NORMAL WITH ONLY MINOR WARMING TRENDS BACK INTO THE LOW AND
MID 80S...FOLLOWED BY COOLING INTO THE 70S BEHIND THE BOUNDARIES.
MID LEVEL BOUNDARY IS EXPECTED TO SET UP ACROSS WESTERN SOUTH DAKOTA
AND NEAR THE MISSOURI VALLEY SATURDAY EVENING. SOME SCATTERED TO
ISOLATED THUNDERSTORMS ARE EXPECTED TO FIRE TO THE WEST OF THE
FORECAST AREA BY AFTERNOON AND COULD DRIFT INTO OUR FAR WESTERN
COUNTIES IN THE EVENING AND OVERNIGHT. MODELS TRACK A MID LEVEL INTO
THE NORTHERN HIGH PLAINS ON SUNDAY AND THROUGH THE FORECAST AREA
SUNDAY NIGHT. WITH SOME WEAK INSTABILITY EXTENDING INTO SOUTH
CENTRAL SOUTH DAKOTA...SCATTERED CONVECTION WILL AGAIN INITIATE
ACROSS OUR WESTERN COUNTIES SUNDAY AFTERNOON AND TRACK ACROSS THE
REMAINDER OF THE FORECAST AREA OVERNIGHT.
MODELS A BIT MORE UNCERTAIN WITH THE TIMING OF WAVES IN THE
EXTENDED. THE GFS BRINGS ANOTHER DECENT SHORTWAVE THROUGH THE
FORECAST AREA MONDAY NIGHT...WHILE THE ECMWF AND GEM ARE MORE
SUBTLE. BETTER AGREEMENT IS SEEN TUESDAY NIGHT WITH A WAVE AND COLD
FRONT DROPPING THROUGH THE REGION. THIS SHOULD ALLOW A COOLER AND
DRIER PUSH TO BRING A BREAK TO THE ACTIVE WEATHER PATTERN WEDNESDAY
THROUGH FRIDAY. DID SCALE BACK ON THE SPOTTY PRECIPITATION CHANCES
GIVEN BY THE ALLBLEND IN THE EXTENDED WITH THE EXCEPTION OF SOUTH
CENTRAL SD WHICH COULD SEE SOME HIGH PLAINS CONVECTION DRIFT INTO
THE AREA.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 628 PM CDT FRI AUG 2 2013
SHOWERS HAVE EXITED EASTERN EDGE OF THE CWA FOR THE START OF THIS
TAF PERIOD...WITH DRY CONDITIONS EXPECTED FOR THE TAF LOCATIONS
THROUGH THE PERIOD. MVFR CEILINGS WHICH DEVELOPED IN THE WAKE OF THE
PRECIPITATION...MAINLY SOUTH OF INTERSTATE 90 AND WEST OF INTERSTATE
29...WILL LINGER INTO THE EARLY-MID EVENING...BUT THIS NOT EXPECTED
TO IMPACT TAF LOCATIONS. WITH THE MORE WIDESPREAD LIGHT RAINFALL
TODAY AND LIGHT WINDS EXPECTED TONIGHT...MAY HAVE TO WATCH FOR FOG
DEVELOPMENT LATE TONIGHT. BUT CONFIDENCE LOW THAT THIS WILL OCCUR
AND WILL HAVE VFR CONDITIONS IN THE TAFS THROUGH THE PERIOD FOR NOW.
POTENTIAL FOR ANOTHER ROUND OF CONVECTION INTO FAR SOUTHWEST PARTS
OF THE FORECAST AREA AFTER 06Z. HOWEVER ANY CONVECTION SHOULD BE
WEST OF TAF LOCATIONS.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
UPDATE...
SHORT TERM...CHAPMAN
LONG TERM...
AVIATION...JH
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
940 PM CDT FRI AUG 2 2013
.UPDATE...
ISSUED AT 940 PM CDT FRI AUG 2 2013
PRECIPITATION ENDED QUICKLY OVER THE AREA LATE THIS AFTERNOON.
SKIES HAVE CLEARED PRETTY WELL WITH LOW CLOUDS LEFT ON THE SOUTH
SIDE OF THE MISSOURI RIVER. MOST OF THESE CLOUDS SHOULD CLEAR OUT
SLOWLY TO THE SOUTHWEST THE REST OF TONIGHT BUT THEY MAY STAY
PRETTY CLOSE AND WILL KEEP SOME CLOUDS HUGGING THE RIVER. A FEW
PATCHY HIGHER CLOUDS EXPECTED TO DRIFT OVER THE AREA AS WARM
ADVECTION EXTENDS ALOFT. AT THIS TIME NOT EXPECTING ANY FOG IN
SOMEWHAT DRIER AIR UNDER BUBBLE HIGH CENTRAL AND EASTERN PART OF
OUR FORECAST AREA. CURRENT LOW TEMPERATURES LOOK PRETTY
GOOD...EARLY COOLING AT A FEW PLACES SUCH AS FSD EXPECTED TO LEVEL
OFF THIS EVENING...HOUR TO HOUR DOWNS AND UPS ARE CERTAINLY
TYPICAL UNDER MOSTLY CLEAR SKIES AND LIGHT WINDS.
&&
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 338 PM CDT FRI AUG 2 2013
MCV PRECIPITATION EXITING THE FAR SOUTHEASTERN CWA AT MID
AFTERNOON...AND MONITORING THE TRAILING EDGE OF NOW SLOWLY
DISSIPATING COMPLEX OF SHOWERS AND ISOLATED THUNDER ACROSS
SOUTHEASTERN SD. SUPPORT FOR LATTER PRECIP IS MID LEVEL LIFT FORCING
WITH WAVE MOVING THROUGH NORTHEAST AND TAILING TOWARD CENTRAL SD.
FEATURE KEEPS CLIPPING ALONG LATE AFTERNOON AND INDICATION ON WATER
VAPOR LOOP FOR SLIGHTLY RISING HEIGHTS IN WHAT HAS BEEN A GRADUALLY
STABILIZED OVERALL AIRMASS AS PRECIPITATION HAS WORKED THROUGH. MID
LEVEL BOUNDARY REMAINS INTO THE NIGHT RIGHT ACROSS THE AREA...BUT
CANNOT REALLY FIND ANY DISTINCT FEATURE TO THINK IT WILL ACTIVATE
BEHIND FEATURE THIS AFTERNOON FOR QUITE SOME TIME. THEREFORE...
HAVE CUT BACK POPS FAIRLY QUICKLY FROM WEST TO EAST THROUGH THE
REMAINDER OF THE AFTERNOON. WHILE HRRR HAS HAD A PRETTY GOOD IDEA TO
EVOLUTION OF PRECIP TODAY...ITS TIMING HAS LEFT QUITE A BIT TO BE
DESIRED...AND LIKELY CONTINUES TOO SLOW OVERALL. RETAINED ISOLATED
THUNDER MENTION MAINLY THROUGH THE MISSOURI CORRIDOR EASTWARD
THROUGH NORTHWEST IOWA...AS WILL STILL HAVE A BIT OF ELEVATED
INSTABILITY TO WORK THROUGH...AND WOULD BE PRUDENT TO KEEP AN EYE TO
THE SOUTHERN END OF THE LINE AS MAY YET PULSE UP IN STRENGTH A BIT
AND PRODUCE A LITTLE HAIL. MUCH OF THE REMAINDER OF THE NIGHT SHOULD
REMAIN QUIET...WITH PARTLY TO MOSTLY CLOUDY SKIES AFTER PERHAPS A
SHORT PERIOD OF POST CONVECTIVE CLEARING.
LATER TONIGHT INTO EARLY SATURDAY...ANOTHER WAVE MOVING THROUGH THE
ROCKIES WILL LIKELY INITIATE NOCTURNAL DEVELOPMENT THROUGH THE HIGH
PLAINS. PROPAGATION OF COMPLEX SHOULD KEEP MOSTLY CLEAR OF THE
AREA...BUT POTENTIAL FOR SOMETHING DEVELOPING INITIALLY NORTH OF THE
BLACK HILLS TO CLIP THE FAR SOUTHWEST. EASTERN LOCATIONS WILL BE
PROTECTED OF SORTS BY RIDGE OF HIGH PRESSURE AND SOMEWHAT DRIER
NORTHEAST TO EAST LOW LEVEL FLOW. SHOULD BE FAIRLY OPEN TO MIX
TOWARD 850-800 HPA ON SATURDAY WHICH WOULD YIELD AN ABUNDANCE OF MID
70S TO NEAR 80 ACROSS THE AREA.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 338 PM CDT FRI AUG 2 2013
FAIRLY ACTIVE WEATHER PATTERN CONTINUES FOR THE BULK OF NEXT WEEK
WITH SEVERAL WAVE DROPPING ACROSS THE NORTHERN PLAINS ALONG THE
NORTHWESTERLY UPPER LEVEL FLOW. OVERALL TEMPERATURE TRENDS REMAIN
BELOW NORMAL WITH ONLY MINOR WARMING TRENDS BACK INTO THE LOW AND
MID 80S...FOLLOWED BY COOLING INTO THE 70S BEHIND THE BOUNDARIES.
MID LEVEL BOUNDARY IS EXPECTED TO SET UP ACROSS WESTERN SOUTH DAKOTA
AND NEAR THE MISSOURI VALLEY SATURDAY EVENING. SOME SCATTERED TO
ISOLATED THUNDERSTORMS ARE EXPECTED TO FIRE TO THE WEST OF THE
FORECAST AREA BY AFTERNOON AND COULD DRIFT INTO OUR FAR WESTERN
COUNTIES IN THE EVENING AND OVERNIGHT. MODELS TRACK A MID LEVEL INTO
THE NORTHERN HIGH PLAINS ON SUNDAY AND THROUGH THE FORECAST AREA
SUNDAY NIGHT. WITH SOME WEAK INSTABILITY EXTENDING INTO SOUTH
CENTRAL SOUTH DAKOTA...SCATTERED CONVECTION WILL AGAIN INITIATE
ACROSS OUR WESTERN COUNTIES SUNDAY AFTERNOON AND TRACK ACROSS THE
REMAINDER OF THE FORECAST AREA OVERNIGHT.
MODELS A BIT MORE UNCERTAIN WITH THE TIMING OF WAVES IN THE
EXTENDED. THE GFS BRINGS ANOTHER DECENT SHORTWAVE THROUGH THE
FORECAST AREA MONDAY NIGHT...WHILE THE ECMWF AND GEM ARE MORE
SUBTLE. BETTER AGREEMENT IS SEEN TUESDAY NIGHT WITH A WAVE AND COLD
FRONT DROPPING THROUGH THE REGION. THIS SHOULD ALLOW A COOLER AND
DRIER PUSH TO BRING A BREAK TO THE ACTIVE WEATHER PATTERN WEDNESDAY
THROUGH FRIDAY. DID SCALE BACK ON THE SPOTTY PRECIPITATION CHANCES
GIVEN BY THE ALLBLEND IN THE EXTENDED WITH THE EXCEPTION OF SOUTH
CENTRAL SD WHICH COULD SEE SOME HIGH PLAINS CONVECTION DRIFT INTO
THE AREA.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 628 PM CDT FRI AUG 2 2013
SHOWERS HAVE EXITED EASTERN EDGE OF THE CWA FOR THE START OF THIS
TAF PERIOD...WITH DRY CONDITIONS EXPECTED FOR THE TAF LOCATIONS
THROUGH THE PERIOD. MVFR CEILINGS WHICH DEVELOPED IN THE WAKE OF THE
PRECIPITATION...MAINLY SOUTH OF INTERSTATE 90 AND WEST OF INTERSTATE
29...WILL LINGER INTO THE EARLY-MID EVENING...BUT THIS NOT EXPECTED
TO IMPACT TAF LOCATIONS. WITH THE MORE WIDESPREAD LIGHT RAINFALL
TODAY AND LIGHT WINDS EXPECTED TONIGHT...MAY HAVE TO WATCH FOR FOG
DEVELOPMENT LATE TONIGHT. BUT CONFIDENCE LOW THAT THIS WILL OCCUR
AND WILL HAVE VFR CONDITIONS IN THE TAFS THROUGH THE PERIOD FOR NOW.
POTENTIAL FOR ANOTHER ROUND OF CONVECTION INTO FAR SOUTHWEST PARTS
OF THE FORECAST AREA AFTER 06Z. HOWEVER ANY CONVECTION SHOULD BE
WEST OF TAF LOCATIONS.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
UPDATE...
SHORT TERM...CHAPMAN
LONG TERM...
AVIATION...JH
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
628 PM CDT FRI AUG 2 2013
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 338 PM CDT FRI AUG 2 2013
MCV PRECIPITATION EXITING THE FAR SOUTHEASTERN CWA AT MID
AFTERNOON...AND MONITORING THE TRAILING EDGE OF NOW SLOWLY
DISSIPATING COMPLEX OF SHOWERS AND ISOLATED THUNDER ACROSS
SOUTHEASTERN SD. SUPPORT FOR LATTER PRECIP IS MID LEVEL LIFT FORCING
WITH WAVE MOVING THROUGH NORTHEAST AND TAILING TOWARD CENTRAL SD.
FEATURE KEEPS CLIPPING ALONG LATE AFTERNOON AND INDICATION ON WATER
VAPOR LOOP FOR SLIGHTLY RISING HEIGHTS IN WHAT HAS BEEN A GRADUALLY
STABILIZED OVERALL AIRMASS AS PRECIPITATION HAS WORKED THROUGH. MID
LEVEL BOUNDARY REMAINS INTO THE NIGHT RIGHT ACROSS THE AREA...BUT
CANNOT REALLY FIND ANY DISTINCT FEATURE TO THINK IT WILL ACTIVATE
BEHIND FEATURE THIS AFTERNOON FOR QUITE SOME TIME. THEREFORE...
HAVE CUT BACK POPS FAIRLY QUICKLY FROM WEST TO EAST THROUGH THE
REMAINDER OF THE AFTERNOON. WHILE HRRR HAS HAD A PRETTY GOOD IDEA TO
EVOLUTION OF PRECIP TODAY...ITS TIMING HAS LEFT QUITE A BIT TO BE
DESIRED...AND LIKELY CONTINUES TOO SLOW OVERALL. RETAINED ISOLATED
THUNDER MENTION MAINLY THROUGH THE MISSOURI CORRIDOR EASTWARD
THROUGH NORTHWEST IOWA...AS WILL STILL HAVE A BIT OF ELEVATED
INSTABILITY TO WORK THROUGH...AND WOULD BE PRUDENT TO KEEP AN EYE TO
THE SOUTHERN END OF THE LINE AS MAY YET PULSE UP IN STRENGTH A BIT
AND PRODUCE A LITTLE HAIL. MUCH OF THE REMAINDER OF THE NIGHT SHOULD
REMAIN QUIET...WITH PARTLY TO MOSTLY CLOUDY SKIES AFTER PERHAPS A
SHORT PERIOD OF POST CONVECTIVE CLEARING.
LATER TONIGHT INTO EARLY SATURDAY...ANOTHER WAVE MOVING THROUGH THE
ROCKIES WILL LIKELY INITIATE NOCTURNAL DEVELOPMENT THROUGH THE HIGH
PLAINS. PROPAGATION OF COMPLEX SHOULD KEEP MOSTLY CLEAR OF THE
AREA...BUT POTENTIAL FOR SOMETHING DEVELOPING INITIALLY NORTH OF THE
BLACK HILLS TO CLIP THE FAR SOUTHWEST. EASTERN LOCATIONS WILL BE
PROTECTED OF SORTS BY RIDGE OF HIGH PRESSURE AND SOMEWHAT DRIER
NORTHEAST TO EAST LOW LEVEL FLOW. SHOULD BE FAIRLY OPEN TO MIX
TOWARD 850-800 HPA ON SATURDAY WHICH WOULD YIELD AN ABUNDANCE OF MID
70S TO NEAR 80 ACROSS THE AREA.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 338 PM CDT FRI AUG 2 2013
FAIRLY ACTIVE WEATHER PATTERN CONTINUES FOR THE BULK OF NEXT WEEK
WITH SEVERAL WAVE DROPPING ACROSS THE NORTHERN PLAINS ALONG THE
NORTHWESTERLY UPPER LEVEL FLOW. OVERALL TEMPERATURE TRENDS REMAIN
BELOW NORMAL WITH ONLY MINOR WARMING TRENDS BACK INTO THE LOW AND
MID 80S...FOLLOWED BY COOLING INTO THE 70S BEHIND THE BOUNDARIES.
MID LEVEL BOUNDARY IS EXPECTED TO SET UP ACROSS WESTERN SOUTH DAKOTA
AND NEAR THE MISSOURI VALLEY SATURDAY EVENING. SOME SCATTERED TO
ISOLATED THUNDERSTORMS ARE EXPECTED TO FIRE TO THE WEST OF THE
FORECAST AREA BY AFTERNOON AND COULD DRIFT INTO OUR FAR WESTERN
COUNTIES IN THE EVENING AND OVERNIGHT. MODELS TRACK A MID LEVEL INTO
THE NORTHERN HIGH PLAINS ON SUNDAY AND THROUGH THE FORECAST AREA
SUNDAY NIGHT. WITH SOME WEAK INSTABILITY EXTENDING INTO SOUTH
CENTRAL SOUTH DAKOTA...SCATTERED CONVECTION WILL AGAIN INITIATE
ACROSS OUR WESTERN COUNTIES SUNDAY AFTERNOON AND TRACK ACROSS THE
REMAINDER OF THE FORECAST AREA OVERNIGHT.
MODELS A BIT MORE UNCERTAIN WITH THE TIMING OF WAVES IN THE
EXTENDED. THE GFS BRINGS ANOTHER DECENT SHORTWAVE THROUGH THE
FORECAST AREA MONDAY NIGHT...WHILE THE ECMWF AND GEM ARE MORE
SUBTLE. BETTER AGREEMENT IS SEEN TUESDAY NIGHT WITH A WAVE AND COLD
FRONT DROPPING THROUGH THE REGION. THIS SHOULD ALLOW A COOLER AND
DRIER PUSH TO BRING A BREAK TO THE ACTIVE WEATHER PATTERN WEDNESDAY
THROUGH FRIDAY. DID SCALE BACK ON THE SPOTTY PRECIPITATION CHANCES
GIVEN BY THE ALLBLEND IN THE EXTENDED WITH THE EXCEPTION OF SOUTH
CENTRAL SD WHICH COULD SEE SOME HIGH PLAINS CONVECTION DRIFT INTO
THE AREA.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 628 PM CDT FRI AUG 2 2013
SHOWERS HAVE EXITED EASTERN EDGE OF THE CWA FOR THE START OF THIS
TAF PERIOD...WITH DRY CONDITIONS EXPECTED FOR THE TAF LOCATIONS
THROUGH THE PERIOD. MVFR CEILINGS WHICH DEVELOPED IN THE WAKE OF THE
PRECIPITATION...MAINLY SOUTH OF INTERSTATE 90 AND WEST OF INTERSTATE
29...WILL LINGER INTO THE EARLY-MID EVENING...BUT THIS NOT EXPECTED
TO IMPACT TAF LOCATIONS. WITH THE MORE WIDESPREAD LIGHT RAINFALL
TODAY AND LIGHT WINDS EXPECTED TONIGHT...MAY HAVE TO WATCH FOR FOG
DEVELOPMENT LATE TONIGHT. BUT CONFIDENCE LOW THAT THIS WILL OCCUR
AND WILL HAVE VFR CONDITIONS IN THE TAFS THROUGH THE PERIOD FOR NOW.
POTENTIAL FOR ANOTHER ROUND OF CONVECTION INTO FAR SOUTHWEST PARTS
OF THE FORECAST AREA AFTER 06Z. HOWEVER ANY CONVECTION SHOULD BE
WEST OF TAF LOCATIONS.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
SHORT TERM...CHAPMAN
LONG TERM...
AVIATION...JH
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
1117 PM CDT WED JUL 31 2013
.DISCUSSION...
LOOK FOR VFR CONDITIONS TO CONTINUE ACROSS WEST CENTRAL TEXAS FOR
THE NEXT 24 HOURS. AVIATION BELOW HAS DETAILS.
&&
.AVIATION...
MODELS THIS CYCLE INDICATE NO NEED TO DEVIATE FROM THE PREVIOUS
TERMINAL FORECAST. SURFACE WINDS WILL BE LIGHT AND VARIABLE FOR
THE NEXT 24 HOURS.
HUBER
&&
.PREV DISCUSSION... /ISSUED 913 PM CDT WED JUL 31 2013/
UPDATE...
REMOVING EVENING RAIN CHANCES.
DISCUSSION...
STORMS HAVE NEARLY DISSIPATED AT 9 PM THIS EVENING...WITH ONLY A
FEW SHOWERS NORTH OF STERLING CITY. WITH LOSS OF HEATING...DO NOT
EXPECT REGENERATION DESPITE A WEAK SURFACE TROUGH ACROSS THE
REGION. LOW IN THE MID 70S LOOK GOOD.
04
PREV DISCUSSION... /ISSUED 632 PM CDT WED JUL 31 2013/
DISCUSSION...
LOOK FOR VFR CONDITIONS TO CONTINUE ACROSS WEST CENTRAL TEXAS FOR
THE NEXT 24 HOURS. SEE AVIATION BELOW FOR DETAILS.
AVIATION...
/THIS AFTERNOON AND EARLY EVENING/
.ISOLATED THUNDERSTORMS WITH POSSIBLE DOWNBURSTS...
A SURFACE BOUNDARY EXTENDING ALONG OR NEAR INTERSTATE 20 WILL
CONTINUE TO BE A FOCUS FOR SHOWERS AND THUNDERSTORM DEVELOPMENT
THIS AFTERNOON. WITH LITTLE IF ANY UPPER-LEVEL
SUPPORT...THUNDERSTORMS WILL BE SHORT LIVED. THE FREEZING LEVEL IS
AROUND FOURTEEN THOUSAND FEET ABOVE GROUND LEVEL. THUS...THE HAIL
THREAT IS VERY LOW. HOWEVER...MODEL FORECAST SOUNDING AT SEVERAL
LOCATIONS ACROSS WEST CENTRAL TEXAS INDICATE THE POTENTIAL FOR
DOWNBURST WINDS. THUS...I BELIEVE THAT IS THE PRIMARY THREAT THIS
AFTERNOON AND EVENING. WATCH FOR THUNDERSTORMS TO DISSIPATE AROUND
SUNSET. GIVEN THE ISOLATED NATURE OF THUNDERSTORMS...I DECIDED NOT
TO INCLUDE ANY THUNDER IN ANY OF OUR TERMINALS.
HUBER
/OVERNIGHT AND TOMORROW/
.VFR CONDITIONS WITH LIGHT AND VARIABLE WINDS...
MODELS INDICATE HIGH PRESSURE WILL CONTINUE TO DOMINATE THE REGION
FOR THE NEXT 24 HOURS. THEREFORE...EXPECT SURFACE WINDS TO BE
MAINLY LIGHT AND VARIABLE THROUGH TOMORROW AFTERNOON.
HUBER
PREV DISCUSSION... /ISSUED 346 PM CDT WED JUL 31 2013/
SHORT TERM...
A WEAK COLD FRONT WAS SITUATED ROUGHLY ALONG THE I-20 CORRIDOR THIS
AFTERNOON. THIS FRONT IS EXPECTED TO DROP A BIT FARTHER SOUTH INTO
NORTHERN PORTIONS OF THE CONCHO VALLEY AND HEARTLAND BEFORE STALLING
OUT TONIGHT. THE FRONT WILL BECOME MORE DIFFUSE ON THURSDAY AND
SHOULD WASH OUT ACROSS THE AREA BY AFTERNOON. AS OF 3 PM...ISOLATED
CONVECTION HAS FORMED JUST AHEAD OF THE FRONT OVER SOUTHERN PORTIONS
OF THE BIG COUNTRY. WILL KEEP ISOLATED CONVECTION IN THE FORECAST
THROUGH EARLY EVENING WITH ACTIVITY EXPECTED TO DISSIPATE AFTER
SUNSET WITH LOSS OF HEATING.
CONVECTION HAS ALSO DEVELOPED ACROSS THE HIGHER TERRAIN IN EASTERN
NEW MEXICO THIS AFTERNOON. LATEST NAM AND HRRR INDICATE THAT THIS
ACTIVITY MAY MAKE A RUN AT OUR WESTERN COUNTIES TOWARDS DAYBREAK
THURSDAY AS IT WEAKENS. NOT CONFIDENT THAT THIS WILL HAPPEN SO KEPT
THE FORECAST DRY OVERNIGHT. DRY AND HOT CONDITIONS CONTINUE THURSDAY
AFTERNOON WITH HIGHS 99 TO 102 AND HEAT INDICES 102 TO 105 DEGREES.
24
LONG TERM...
HOT AND DRY CONDITIONS WILL DOMINATE THE WEATHER ACROSS WEST CENTRAL
TEXAS FROM FRIDAY THROUGH AT LEAST THE MIDDLE OF NEXT WEEK. THE
SURFACE HIGH THAT IS CURRENTLY CENTERED OVER NEW MEXICO WILL
REPOSITION ITSELF OVER TEXAS THROUGH AT LEAST THE NEXT 7 DAYS. THIS
WILL RESULT IN NEAR NIL RAIN CHANCES...WITH HIGH TEMPERATURES
RANGING FROM 98 TO 103...WHILE OVERNIGHT LOWS FALL INTO THE MID AND
UPPER 70S. VERY LITTLE RELIEF IN THE HOT AND DRY PATTERN IS EXPECTED
THROUGH THE NEXT 7 DAYS...AND POSSIBLY BEYOND...AS THE UPPER LEVEL
HIGH REMAINS PARKED OVER THE LONE STAR STATE.
DANIELS
&&
.PRELIMINARY POINT TEMPS/POPS...
ABILENE 76 100 75 101 75 / 5 5 0 0 0
SAN ANGELO 75 101 75 101 74 / 5 5 0 0 0
JUNCTION 75 99 73 99 72 / 5 0 0 0 0
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
24/DANIAELS/HUBER
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
1015 AM EDT THU AUG 1 2013
.SYNOPSIS...
A COLD FRONT WILL MOVE SOUTHEAST THROUGH THE AREA TODAY INTO THIS
EVENING...PRECEDED AND ACCOMPANIED BY SCATTERED SHOWERS AND
THUNDERSTORMS. CLEARING SKIES ALONG WITH DRIER AIR WILL FOLLOW THE
FRONT...AND REMAIN OVER THE REGION ON FRIDAY.
ANOTHER COLD FRONT WILL BE ON ITS HEELS AND BRING A RETURN OF
SHOWERS TO THE FORECAST ON SATURDAY. A STRONGER AREA OF HIGH
PRESSURE SETTLES OVER THE REGION EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1015 AM EDT THURSDAY...
MOIST LOW LEVELS WITH NORTHWEST FLOW AHEAD OF A SLOW MOVING FRONT
IN THE OHIO VALLEY...HAS LIGHT SPOTTY SHOWERS MOVING SOUTHEAST
ACROSS THE MOUNTAINS THIS MORNING. HRRR HANDLING THIS THE BEST
THIS MORNING. UPDATED POPS TO CURRENT CONDITIONS.
AS OF 345 AM EDT THURSDAY...LEADING EDGE OF TROPICAL AIR WITH
DEW POINTS AROUND 70F RESIDING FROM NEAR FARMVILLE SOUTHWEST TO
NEAR DANVILLE VA AND GREENSBORO NC...CONTINUING SOUTHWEST TO NEAR
CHARLOTTE NC. SLIGHT BACKING OF WINDS ALOFT IN ADVANCE OF
APPROACHING TROF DIVING SOUTHEAST OUT OF THE UPPER MS AND OH
VALLEY...COUPLED WITH ONSET OF DAYTIME HEATING SHOULD ENABLE WARM
FRONT TO LIFT/MIX SLOWLY NORTHWARD INTO AT LEAST SOUTHEASTERN
PIEDMONT COUNTIES BEFORE SURFACE COLD FRONT...NOW MOVING SOUTHEAST
THROUGH SOUTHERN OH AND NORTHWESTERN KY...JUMPS INTO DEVELOPING
LEE TROF EAST OF THE BLUE RIDGE AND HALTS NORTHWARD PUSH OF SULTRY
AIRMASS.
PLENTY OF CLOUDS AND EARLIER ARRIVAL OF COLD FRONT AND/OR WINDS
VEERING INTO THE WEST SHOULD MINIMIZE SIGNIFICANT CONVECTIVE
THREAT TODAY ALONG AND WEST OF THE BLUE RIDGE...WITH ONLY
SCATTERED SHOWERS/THUNDERSTORMS EXPECTED UP UNTIL FRONTAL PASSAGE
BY EARLY TO MID AFTERNOON...FOLLOWED BY SOME LINGERING SHOWERS IN
UPSLOPE AREAS PERHAPS INTO EARLY EVENING AS TEMPERATURES ALOFT
SLOWLY COOL WITH APPROACH OF TROF AXIS.
HOWEVER...DESPITE PLENTY OF CLOUDS ACROSS THE PIEDMONT...AT LEAST
INITIALLY...EROSION OF COOL POOL...PROXIMITY OF CONFLUENCE IN
VICINITY OF WARM FRONT/LEE TROF...AND GREATER INSTABILITY DUE TO A
MUCH MORE MOIST AIRMASS AND PERHAPS SOME INSOLATION...ESPECIALLY
SOUTH OF THE FRONT...MAY SUPPORT MORE AGGRESSIVE THUNDERSTORM
DEVELOPMENT...WITH EVEN SOME ISOLATED SEVERE WEATHER POSSIBLE
THIS AFTERNOON ACROSS THE EXTREME SOUTHEASTERN VA/NC COUNTIES.
SOUTHEASTERN AREAS MAY ALSO SEE SOME LOCALLY HEAVY RAIN...BUT
HEAVY RAIN THAT OCCURRED EARLIER TONIGHT WAS RELATIVELY LOCALIZED
TO ONLY A SMALL PORTION OF A FEW COUNTIES...SO DO NOT PLAN ON
ISSUING ANY FLASH FLOOD WATCH AT THE PRESENT TIME...ALTHOUGH
POTENTIAL OF DOES EXIST FOR SOME LOCALIZED FLOODING ISSUES IF
STORMS TRAIN OVER THE SAME AREA IN CASWELL....PITTSYLVANIA...AND
HALIFAX COUNTIES.
THREAT OF PRECIPITATION EXPECTED TO RAPIDLY END OVER THE ENTIRE
BLACKSBURG FORECAST AREA THIS EVENING WITH LOSS OF DAYTIME HEATING
AND PASSAGE OF FRONT...TO BE FOLLOWED BY CLEARING SKIES WITH
DIMINISHING WINDS. WEAK SUBSIDENCE OVER MOIST BOUNDARY LAYER FROM
RECENT RAINFALL SHOULD SET THE STAGE FOR DEVELOPMENT OF FOG IN
MANY AREAS BY DAYBREAK FRIDAY...AND HAVE INCLUDED IN THE GRIDDED
FORECAST.
CONTINUED TO UNDERCUT MOS GUIDANCE FOR HIGH TEMPERATURES TODAY IN
MOST AREAS...THAT WILL REMAIN LOCKED IN COOL WEDGE UNTIL BEING
DISLODGED BY ARRIVAL OF WESTERLY WINDS AND COOL FRONT. PREFERRED
SOMEWHAT COOLER MAV GUIDANCE IN THE MOUNTAINS FOR LOW TEMPERATURES
TONIGHT (MOS GUIDANCE GENERALLY ACCEPTED ELSEWHERE) WITH ARRIVAL
OF SOMEWHAT LOWER DEW POINTS AS THE NIGHT PROGRESSES.
&&
.SHORT TERM /FRIDAY THROUGH SUNDAY NIGHT/...
AS OF 430 AM EDT THURSDAY...
VERY LITTLE CHANGE EXPECTED IN THE UPPER ATMOSPHERIC PATTERN
THROUGH THE PERIOD WITH UPPER RIDGE LOCKED IN ACROSS THE SOUTHWEST
AND A DEEP/BROAD UPPER LOW ANCHORED ACROSS HUDSON BAY. THIS WILL
KEEP A LONG FETCH OF NW FLOW ACROSS THE REGION. AS A RESULT...THE
AREA REMAINS SUSCEPTIBLE TO ANY EMBEDDED NW FLOW DISTURBANCES AS A
RESULT AN OVERALL UNSETTLED PATTERN WILL REMAIN IN PLACE.
FRIDAY...THE AREA WILL BE BETWEEN SHORT WAVES...WITH THE THU
SYSTEM EXITING OFF THE COAST AND THE NEXT UPSTREAM SHORT WAVE
NOTED ACROSS THE UPPER MIDWEST. FRIDAY SHOULD OVERALL BE A QUIET
DAY WITH LOWER DEWPOINTS. ABUNDANT INSOLATION AND SOME WARMING AT
850MB AHEAD OF THE NEXT SHORT WAVE WILL OFFSET ANY EARLY CAA. THE
NET RESULT WILL BE NEAR NORMAL TEMPERATURES.
FOR SATURDAY...FAIRLY IMPRESSIVE FORCING FROM NW FLOW UPPER SHORT
WAVE TRACKS ACROSS THE AREA DURING PEAK HEATING. THE LIMITING
FACTOR IS SFC BASED INSTABILITY...WITH ANTECEDENT LOW DEWPOINTS
AS THE AIR MASS HAS LIMITED TIME TO RECOVER FROM THE DRY AIR MASS
IN PLACE FRIDAY. FEEL THAT DYNAMICS AND ELEVATED INSTABILITY WILL
ALLOW FOR AT LEAST SOME THUNDER...SO HAVE INTRODUCED THUNDER IN
THE AFTERNOON/EVENING. SPC HAS OUTLOOKED THE NORTHERN PART OF THE
CWA FOR 5 PERCENT RISK...MAINLY FROM THE STANDPOINT OF HEALTHY
SHEAR/DYNAMICS/UPPER FORCING. HOWEVER...AS NOTED...INSTABILITY IS
SEVERELY LACKING AT THIS POINT...SO AM NOT IMPRESSED. ANOTHER
ISSUE FOR SAT ARE MAX TEMPS. GFS HAS PROGGED AN AREA OF +20C TO
ADVECT NE INTO THE REGION FROM THE SE STATES SAT AFTERNOON...AND
AS A RESULT HAS PUSHED MAX TEMPS INTO THE LOW 90S ACROSS THE
PIEDMONT. ECMWF IS CONSIDERABLY COOLER. BASED ON THE PERSISTENT
COOL SUMMER AND RELATIVELY LOW MIN TEMPS EXPECTED SAT MORNING...I
JUST CANT BUY OFF ON THE 90S ADVERTISED BY THE GFS...ESPECIALLY
WITH THE VERY WET GROUND IN PLACE...SO HAVE TRENDED TOWARD THE
CONSIDERABLY COOLER ECMWF MOS. HAVE KEPT POPS IN THE CHC CATEGORY
FOR NOW AS WELL. THIS SYSTEM WILL LINGER ACROSS THE SOUTHERN PART
OF THE CWA SUN...SO HAVE KEPT CHC POPS ACROSS THE SOUTH AND SLIGHT
CHC NORTH AS THE ECMWF IS SOMEWHAT SLOWER IN PUSHING THE MOISTURE
SOUTH OF THE AREA. LOWER DEWPOINTS AND TEMPERATURES SHOULD BEGIN
TO ADVECT INTO THE REGION FROM THE NORTH SUN.
&&
.LONG TERM /MONDAY THROUGH WEDNESDAY/...
AS OF 500 AM EDT THURSDAY...
NORTHWEST FLOW WILL REMAIN IN PLACE THROUGH THE EXTENDED
PERIODS...CONTINUING TO LEAVE THE AREA SUSCEPTIBLE TO SHOWERS AND
THUNDERSTORMS. HOWEVER...THE MODELS ARE FAIRLY INSISTENT IN
PUSHING THE DEEPER MOISTURE SOUTH OF THE AREA. THE BAROCLINIC ZONE
LOOMS JUST TO OUR SE AND IS SUBJECT TO RETURN NORTH WITH ANY OF
THESE SHORT WAVES AT ANY TIME. HAVE NOT MADE ANY SIGNIFICANT
CHANGES TO EARLIER THINKING...ALTHOUGH PUSHED CHC POPS BACK INTO
THE AREA A LITTLE SOONER ON MON THAN EARLIER INDICATED. THERE ARE
LARGE DISCREPANCIES BETWEEN THE GFS/ECMWF IN DEWPOINTS...WITH THE
GFS VERY DRY/COOL...AND THE ECMWF MUCH MORE TEMPERATE...SUGGESTING
BETTER CHCS FOR SHRA ACTIVITY.
PREVIOUS EXTENDED DISCUSSION...
KEEPING WITH A BLEND OF THE 00Z ECMWF/06Z GFS IN THE FIRST COUPLE OF
DAYS THIS PERIOD THEN TRANSITIONING MORE TOWARD ECM/WPC BLEND.
STILL NOT LOOKING AT A WHOLE LOT OF PRECIPITATION OVERALL BUT THE NW
FLOW WITH BROAD TROUGH OVER THE NE INTO THE MID ATLANTIC WILL KEEP
SOME FRONTAL SYSTEMS MOVING THROUGH OVER THIS PERIOD WITH BOUNDARY
WASHING OUT/STALLING OUT TO OUR SOUTH. MOSTLY LOOKING AT JUST BELOW
NORMAL TEMPERATURE SETUP AT LEAST AFTER THE FIRST FRONT PASSES BY
SUNDAY AFTERNOON.
HIGH PRESSURE WILL SETTLE OVER THE MID ATLANTIC MONDAY FOLLOWED BY
ANOTHER SHORTWAVE AND ATTENDANT FRONT FOR EARLY TUESDAY. KEPT POPS
OVERALL IN THE SLIGHT CHANCE TO CHANCE RANGE...BUT APPEARS THE
PATTERN FAVORS THE WRN SLOPES OF WV/SW VA INTO NW NC TO HAVE BETTER
THREAT OF SHOWERS OR STORMS NEXT WEEK. THE 06Z GFS AT TIMES SHOWED
CONVECTIVE FEEDBACK/HIGHER QPF BULLSEYES WITH THE FRONT DRAPED OVER
US EARLY NEXT WEEK AND GENERALLY RULED THIS OUT...FAVORING HPC/ECMWF.
AFTER MIDWEEK THE FRONT EXPECTED TO STALL OUT THE SOUTHEAST WHILE
HIGH PRESSURE NOSES IN FROM THE MIDWEST. AT THIS STAGE THE PATTERN
STILL FAVORS SOME THREAT OF SHOWERS BUT OVERALL MID AND UPPER FLOW
STAYS WEST TO NORTHWEST.
&&
.AVIATION /14Z THURSDAY THROUGH MONDAY/...
AS OF 740 AM EDT THURSDAY...
HEAVIER PRECIPITATION HAS MOVED EAST OF THE AREA...LEAVING A FEW
SPRINKLES OR LIGHT SHOWERS...LOW CLOUDS...AND AREAS OF MOSTLY MVFR
BR AROUND THE REGION. EXPECT MAINLY IFR-MVFR CIGS TO PREVAIL
THROUGH 15Z...THEN IMPROVING MOSTLY TO MVFR THROUGH EARLY
AFTERNOON...THEN VFR BY MID TO LATE AFTERNOON. WOULD EXPECT
REDEVELOPMENT OF SHRA AND EVEN TSRA ACROSS THE PIEDMONT...PERHAPS
BEGINNING NEAR THE I-81 CORRIDOR BY 17/18Z AS THE MAIN FRONTAL
BOUNDARY/UPPER SHORT WAVE APPROACH FROM THE WEST. CLOUDS WILL
CLEAR EAST OF THE ALLEGHANYS AFTER 00Z...BUT EXPECT MVFR CIGS TO
LINGER ACROSS EASTERN WV OVERNIGHT...POSSIBLY SCATTERING OUT
BEFORE DAYBREAK. MAIN CONCERN OVERNIGHT WILL BE DEVELOPMENT OF
PATCHY DENSE FOG WITH LIFR CIGS/VSBYS AT LWB/BCB/LYH AND MVFR
DAN/BLF. WINDS WSW TODAY...SHIFTING TO WNW THIS EVENING...SPEEDS
REMAINING 10KTS OR LESS THROUGH TAF VALID PERIOD...BECOMING CALM
OVERNIGHT MOST SITES.
MEDIUM CONFIDENCE IN CIGS/VSBYS THROUGH TAF VALID PERIOD.
HIGH CONFIDENCE IN WIND SPD/DIR THROUGH TAF VALID PERIOD.
MEDIUM CONFIDENCE IN TSRA POTENTIAL PIEDMONT THIS AFTERNOON.
EXTENDED AVIATION DISCUSSION...
VFR EXPECTED FRIDAY OUTSIDE EARLY MORNING PATCHY LIFR-IFR FG/BR.
THE NEXT COLD FRONT IS PROGGED TO MOVE THROUGH THE AREA SATURDAY
EVENING INTO SUNDAY MORNING. ANTICIPATE A RETURN OF SCATTERED
SHOWERS AND STORMS AND SOME AREAS OF SUB-VFR CONDITIONS.
HIGH PRESSURE AND MAINLY VFR CONDITIONS RETURN BY MONDAY. EARLY
MORNING FOG WILL AGAIN BE A POSSIBILITY.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...WERT
NEAR TERM...RCS/WERT
SHORT TERM...RAB
LONG TERM...RAB/WP
AVIATION...DS/JH/RAB/WERT
AREA FORECAST DISCUSSION...UPDATED
NWS SPOKANE WA
853 PM PDT Fri Aug 2 2013
.SYNOPSIS...
Unsettled weather will continue this evening with rain showers
and a few thunderstorms. Lingering showers will be common near
the Canadian border through Saturday. Summer weather will return
next week with a warm up back to normal and small chances of
mainly mountain thunderstorms each day.
&&
.DISCUSSION...
Update this evening was to increase chance of rain overnight
across the basin. HRRR has been consistent the last several runs
of keeping rain going across the basin through the night. It also has
shown very little precip across extreme northeast WA and north ID
as well as Lewiston and areas southeast towards the Camas Prairie
overnight. So adjusted accordingly and lowered chance of precip.
Cannot discount an isolated shower anywhere given the proximity of
the low. Low temps look to be on track, about 2-5 degrees below
average for this time of the year. It was quite a chilly day
today. Looks like we start to rebound tomorrow, although we will
still be about 10 degrees below average.
Nisbet
&&
.AVIATION...
00Z TAFS...An expansive upper-level low over the region will bring
widespread showers and isolated thunderstorms to much of the region.
MVFR/IFR Cigs/Vis will be found under weakening band of light rain
stretching across the Columbia Basin. Further north...showers and
isolated thunderstorms with the potential for heavy rain and
localized vis/cig restrictions at KEAT/KOMK will carry the highest
threat for any thunder through 05z. The exception is near the Camas
Prairie and Blue Mtns where partial clearing could lead to isold
-tsra vcnty of KLWS through 03z. Activity will wane overnight but a
weak midlevel disturbance is likely to get hung over Ern Wa and keep
a cluster of light showers into the early morning. Showers will
once again form along the higher terrain near 17z on Sat.
&&
.PRELIMINARY POINT TEMPS/POPS...
Spokane 55 74 57 84 61 87 / 40 30 10 10 10 10
Coeur d`Alene 53 74 53 83 55 85 / 30 40 10 10 10 10
Pullman 50 74 49 83 50 87 / 20 20 10 10 10 10
Lewiston 56 82 59 92 62 94 / 10 10 10 10 10 10
Colville 52 78 52 87 52 87 / 20 40 20 20 10 10
Sandpoint 51 71 47 81 49 82 / 30 60 30 10 10 20
Kellogg 50 74 51 82 54 84 / 40 40 10 10 10 10
Moses Lake 59 81 58 89 61 92 / 60 10 10 10 0 10
Wenatchee 61 81 61 90 65 92 / 50 20 10 10 0 10
Omak 60 84 57 89 59 92 / 50 30 20 20 20 10
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...None.
&&
$$
AREA FORECAST DISCUSSION
NWS SPOKANE WA
448 PM PDT Fri Aug 2 2013
.SYNOPSIS...
Unsettled weather will continue this evening with rain showers
and a few thunderstorms. Lingering showers will be common near
the Canadian border through Saturday. Summer weather will return
next week with a warm up back to normal and small chances of
mainly mountain thunderstorms each day.
&&
.DISCUSSION...
Rest of today and tonight: Clouds continue to thin across
the East Slopes, Okanogan Highlands, and western Columbia Basin.
This has resulted in an increasing risk for convective showers and
isolated thunderstorms. The main threats with these storms will be
heavy rainfall given the juicy air mass in place (precipitable
water values near to over 1.00") and nearly stationary movement.
Per the last few runs of the HRRR which did a superior job with
the placement of the current convection...this activity this
evening is expected to expand/shift west toward the East Slopes of
the Cascades and portions of Douglas and Grant Counties. This
mainly focuses over northern sections of Chelan and
central/western Okanogan Counties but will need to be closely
monitored for more development closer to the larger burn scars
outside Wenatchee. There is still a risk that a few of these cells
will impact some of the scars from the Byrd, First Creek, and Goat
Fires of 2012.
Meanwhile, the deformation band over the se continues to
shrink and HRRR suggest this will continue to dissipate this
evening. These features tend to linger longer then expected and
this was evident with each run of the HRRR this afternoon which
now lingers the band through 02z. Partial clearing south of this
band has resulted in developing showers from the Blue Mtns to the
L-C Valley to the Camas Prairie. Nothing real strong but a stray
thunderstorm will be possible before sunset.
The next feature of note will be a stronger wave that will wrap
around the northern periphery of the low. This wave was over NW MT
today and has since crossed into SE BC. Some guidance dives this
wave along with a cluster of heavier showers into the northern
mountains this evening into the overnight periods but others,
including the latest run of the HRRR now keep this feature just
along or north of the border. Given the high degree of
uncertainty...we have kept at least a chance of showers for most
locations through the overnight periods but confidence is not
exceptionally high locations like Spokane, CDA, and the Palouse
will experience much more precipitation once the current
deformation band dissipates. /sb
Saturday through Monday night...A closed low that brought the
moist and unsettled weather will pull away from the area into
northern Montana on Saturday. This will bring about the beginning
of a warming and drying trend into Monday. However a broad upper
level trough will remain over the area with a weak short wave
clipping the Canadian border Sunday into Monday. This combined
with abundant low level moisture should provide adequate
instability for diurnally driven showers and mainly isolated
thunderstorms primarily along the East Slopes of the Cascades, and
northern mountains. The NAM model has uncapped CAPE values of
300-700 J/KG each afternoon in these areas. Weak shear values will
support mainly pulse type thunderstorms that last only brief
periods of time. However light steering flow will also be slow
moving storms that could produce locally heavy rain. JW
Tuesday through Friday...A struggle between a ridge trying to
poke its way into the region, and upper level troughs on either side of
the ridge will be ongoing for much of next week. While the ridge
may help keep things on the warm side of normal (by about 3 to 6
degrees), an active large scale trough over the central US will
likely allow thunderstorms to develop each afternoon over the
higher terrain. Our confidence is not high that the precipitation
will make it much off the terrain, at least until a better
organized weather system gets closer to the region. The models are
hinting at one such feature moving over the Inland Northwest by
the end of the week. If this were to occur, temperatures would
likely cool by a few degrees and precipitation chances would be
higher over a larger area. ty
&&
.AVIATION...
00Z TAFS...An expansive upper-level low over the region will bring
widespread showers and isolated thunderstorms to much of the region.
MVFR/IFR Cigs/Vis will be found under weakening band of light rain
stretching across the Columbia Basin. Further north...showers and
isolated thunderstorms with the potential for heavy rain and
localized vis/cig restrictions at KEAT/KOMK will carry the highest
threat for any thunder through 05z. The exception is near the Camas
Prairie and Blue Mtns where partial clearing could lead to isold
-tsra vcnty of KLWS through 03z. Activity will wane overnight but a
weak midlevel disturbance is likely to get hung over Ern Wa and keep
a cluster of light showers into the early morning. Showers will
once again form along the higher terrain near 17z on Sat.
&&
.PRELIMINARY POINT TEMPS/POPS...
Spokane 55 74 57 84 61 87 / 50 30 10 10 10 10
Coeur d`Alene 53 74 53 83 55 85 / 60 40 10 10 10 10
Pullman 50 74 49 83 50 87 / 50 20 10 10 10 10
Lewiston 56 82 59 92 62 94 / 40 10 10 10 10 10
Colville 52 78 52 87 52 87 / 90 40 20 20 10 10
Sandpoint 51 71 47 81 49 82 / 80 60 30 10 10 20
Kellogg 50 74 51 82 54 84 / 60 40 10 10 10 10
Moses Lake 59 81 58 89 61 92 / 60 10 10 10 0 10
Wenatchee 61 81 61 90 65 92 / 40 20 10 10 0 10
Omak 60 84 57 89 59 92 / 90 30 20 20 20 10
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...None.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS MILWAUKEE/SULLIVAN WI
915 PM CDT FRI AUG 2 2013
.UPDATE...
CONVECTION CONTINUES TO FIRE FROM NW OHIO ACROSS NRN INDIANA TO N
CENTRAL ILLINOIS IN REGION OF DEEP MOISTURE CONVERGENCE AHEAD OF
SFC DEW POINT GRADIENT EXTENDING FROM NRN IN ACROSS NRN IL...WITH
1000 J/KG OF MOST-UNSTABLE CAPE. VORTICITY ADVECTION-DRIVEN LIGHT
RAIN SHOWERS AHEAD OF VORT MAX IN SE MN BRUSHING SW WI/NW IL WITH
LITTLE TO NO GROUND TRUTH AS PCPN FALLS INTO DRY LAYER BELOW 10K
FT...WITH DRY AIR TO CONTINUE TO OVERSPREAD SRN WI EXPECT NOTHING
MORE THAN A FEW SPRINKLES OR LIGHT DRIZZLE/SEE 0135Z KDEH OB/IN
THE FAR SW...ENDING BY 12 MIDNIGHT AS VORT MAX PASSES TO THE
SOUTHEAST.
&&
.AVIATION/06Z TAFS/...
VFR CONDITIONS THROUGH THE FORECAST AS DRIER AIR SPREADS INTO THE
REGION WITH A RIDGE OF CANADIAN HIGH PRESSURE BUILDING OVER THE
UPPER MIDWEST. LIGHT NW WINDS WILL SHIFT NORTH OVERNIGHT AND NORTHEAST
IN THE MORNING WITH THE HIGH...WITH AN AFTERNOON LAKE BREEZE
TURNING WINDS TO THE EAST AT KMKE AND POSSIBLY AS FAR INLAND AS
KENW. DRY AIR MEANS AT THE MOST SCT AFTERNOON CU.
&&
.PREV DISCUSSION... /ISSUED 320 PM CDT FRI AUG 2 2013/
VERY SHORT TERM...TONIGHT AND SATURDAY.
SURFACE COOL FRONT/DRYLINE HAS SHIFTED SOUTH. RENEWED CONVECTIVE
DEVELOPMENT IN NRN IL INVOF BETTER LOW LEVEL FRONTAL CONVERGENCE.
MUCH DRIER AIR ADVECTING SE INTO SRN WI PER ISODROSOTHERM ANALYSIS.
500 MILLIBAR PROGS SHOW ELONGATED/SHEARED VORT ACROSS THE CWA DURING
THE NIGHT. MID/HIGH LEVEL CLOUDS ON THE INCREASE INTO THE EVENING
ASSOCIATED WITH RAIN MOVING ACROSS NRN IA. THE HRRR BRUSHES THE
SOUTH WITH THIS. THE 00Z ECMWF HINTS AT THIS AS WELL WITH OTHER
MODELS SHOWING DRY AFTER 00Z. CONSSHORT POPS SKIRT THE FAR SOUTH
WITH SMALL POPS EARLY THIS EVENING. SEEMS REASONABLE AND WILL BLEND
WITH THE SRN NEIGHBORS.
NORTHWEST UPPER FLOW PERSISTS. ALL MODELS BRING A 500 MILLIBAR
SHORTWAVE ACROSS. THE NAM HAS THE STRONGER LOOK TO THIS FEATURE
WHILE OTHER MODELS SHOW A CONTINUATION OF THE MORE SHEARED LOOK TO
THE VORT PATTERN. BUFKIT SOUNDINGS SHOW THAT THE AIRMASS WILL BE DRY
AND STABLE SO STICKING WITH THE ADVERTISED DRY FORECAST. SURFACE
HIGH BUILDS IN FROM CANADA AND RIDGES SOUTHEAST INTO WRN GREAT
LAKES. 925 TEMPS 17-19C TRANSLATE TO MID TO UPPER 70S WITH SOME
COOLER TEMPS EVOLVING AS WINDS TURN MORE NE NEAR LAKE MICHIGAN.
SHORT TERM...SATURDAY NIGHT THROUGH MONDAY.
SHORT TERM GUIDANCE IN GOOD AGREEMENT ON HIGH PRESSURE AND DRY
COLUMN IN CONTROL OF OUR WEATHER THROUGH SUNDAY. DAYTIME
TEMPERATURES WILL REMAIN SLIGHTLY BELOW NORMAL FOR EARLY AUGUST AS
NORTHWEST LOW LEVEL FLOW PERSISTS. WARMER AIR BEGINS TO SLOWLY
RETURN SUNDAY NIGHT AND MONDAY. 12Z NAM MOST AGRESSIVE SHOWING MCS
SKIRTING SOUTHWEST WI SUNDAY NIGHT DESPITE RELATIVELY WEAKER LOW
LEVEL RETURN FLOW. 12Z NAM APPEARS TO BE OVERDOING AMOUNT OF UPPER
LEVEL DIVERGENCE ASSOCD WITH 3H JET. EVEN THOUGH OTHER GUIDANCE
INCLUDING GFS AND ECMWF FOCUSES FARTHER WEST...LOW TO MID LEVEL RH
DOES INCREASE OVERNIGHT WITH WEAK LAYER Q-VECTOR CONVERGENCE
SPREADING INTO SRN WI. NOT ENOUGH CONFIDENCE AT THIS POINT TO
TOTALLY REMOVE POPS FOR LATER SUN NIGHT. WL CONTINUE POPS FOR
MONDAY AS WELL AS WEAK MID-LEVEL TROUGH APPROACHES AND COLUMN
MOISTURE CONTINUES TO INCREASE.
LONG TERM...MONDAY NIGHT THROUGH FRIDAY.
MEDIUM RANGE GUIDANCE IN FAIR AGREEMENT ON CARRYING SHORT WAVE
TROUGH AND WEAK COLD FRONT ACROSS WESTERN GREAT LAKES DURING THE
FIRST HALF OF NEXT WEEK. SOME TIMING DIFFERENCES WITH GEM AND GFS
SLIGHTLY FASTER THAN THE LATEST ECMWF. NEVER THE LESS...LEANING
TOWARD THREAT OF CONVECTION WITH SURGE OF WARM AIR ADVECTION MONDAY
NIGHT INTO EARLY TUESDAY WITH CHANCE RETURNING LATER TUESDAY AND
TUESDAY NIGHT ASSOCIATED WITH STRONGER LAYER FORCING WITH CDFNT AND
MID-LEVEL WAVE.
THEN SLOW MOVING UPPER LOW OVER SOUTH CENTRAL CANADA LINGERS TO THE
NORTH THROUGH THURSDAY NIGHT. DRIER...ZONAL FLOW TO THE SOUTH OF
THIS FEATURE SHOULD RESULT IN NEAR OR SLIGHTLY BELOW NORMAL TEMPS
THROUGH THE LATER PART OF THE EXTENDED PERIOD. CANADIAN UPPER LOW
CONTINUES TO WEAKEN LATE IN THE WEEK AND GETS NUDGED EAST FRIDAY AND
SATURDAY.
AVIATION /00Z TAFS/...
SURFACE COOL FRONT/DRY LINE SHIFTING SE OF THE AREA WITH DRIER AIR
BEING BROUGHT IN ON NW WINDS. MOST CU VFR THOUGH A FEW SITES MVFR.
EXPECT THIS TO DISSIPATE DIURNALLY. HRRR DOES SHOW THE NW IA COMPLEX
BRUSHING SW WI LATER THIS EVE BUT WILL LEAVE PRECIP MENTION OUT OF
TAF SITES. HIGH PRESSURE BUILDS IN TO DOMINATE FOR SATURDAY.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...NONE.
&&
$$
UPDATE...REM
TONIGHT/SATURDAY AND AVIATION/MARINE...COLLAR
SATURDAY NIGHT THROUGH FRIDAY...MBK
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
557 PM CDT THU AUG 1 2013
.UPDATE...
ISSUED AT 552 PM CDT THU AUG 1 2013
HAVE TAKEN A STEP TO INCLUDE SOME STRONG TO SEVERE STORM WORDING
IN THE SERVICE PRODUCTS FOR THE EVENING FORECAST FOR NORTHEAST
IOWA.
CURRENT MLCAPE NEAR 1000 J/KG WITH SBCAPE NEAR 1500 J/KG ALONG I-35
CORRIDOR IN IA...WITH A GRADIENT TO NEAR 0 J/KG A FEW COUNTIES
EAST /PER SPC RAPV2 MESO PAGE/. DEEP SHEAR IS IMPRESSIVE WITH SUPERCELL
LIKE NUMBERS OF 0-6KM SHEAR OF 50 KTS. STORMS IN NORTHCENTRAL IA
QUICKLY SHOWED SUPERCELL TRAITS AND SPLITTING BEHAVIOR THIS
AFTERNOON AND HAVE HAD REPORTS OF SEVERE HAIL OR JUST BELOW OVER
THE PAST 1.5 HOURS.
WITH RAP SHORT TERM FORECASTS ADVECTING THE MOISTURE AND WARM
FRONT EAST IN THE NEXT SEVERAL HOURS AND WIND SHEAR REMAINING IN
PLACE...FELT THE NEED TO INCLUDE THIS THREAT INTO THE FORECAST
AREA AND PRODUCTS. WHILE THE RAP BUILDS CAPE EAST...THE LATEST LAPS
ANALYSIS KEPT THE CAPE GRADIENT ON THE WRN FORECAST AREA
BOUNDARY...WRN MITCHELL/FLOYD. THE FORCING FOR THESE STORMS IS WEAK LOW-LEVEL
MOISTURE ADVECTION AND CONVERGENCE...THUS THE AREAL PATTERN TO THE
STORMS...NOT A SURFACE-BASED BOUNDARY. THE BROAD FORCING IN THE
LOW-LEVELS WILL TRY TO MIGRATE EAST TONIGHT TOWARD THE MISSISSIPPI
RIVER PER LATEST RAP GUIDANCE. THUS...EVEN WITH LIMITED CAPE...WANTED TO
BE SAFE WITH STRONG/SEVERE THREATS A BIT INTO THE FORECAST AREA.
SPC UPDATED THE DAY 1 OUTLOOK IN LAST 20 MINS TO ALSO MOVE THE
SLIGHT RISK FURTHER EAST.
STILL EXPECT THE STRONGEST STORMS TO BE RIGHT-MOVING AND THAT
VECTOR IS HARD SOUTH...ABOUT 150 DEGREES AT 30-35 KTS. FOR
NOW...THINKING NE IA FOR THE NEXT FEW HOURS...ESPECIALLY FURTHER
WEST TOWARD I-35.
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 343 PM CDT THU AUG 1 2013
MAIN FORECAST CONCERNS THIS PACKAGE...SHRA/TSRA CHANCES TONIGHT/
FRI...TEMPERATURES.
DATA ANALYSIS AT 18Z HAD BROAD LOW PRESSURE OVER HUDSONS BAY AND A
RIDGE OF HIGH PRESSURE FORM MO TO SASKAT. A WEAK TROUGH WAS LOCATED
NEAR THE MN/DAKOTAS BORDER. IMPACTS OF THE HUDSON BAY LOW ON THE
REGION WERE MAINLY DIURNAL CUMULUS OVER THE NORTHEAST 2/3 OF MN/WI...
AND SUPPORTING THE A SEASONABLY COOL/DRY AIRMASS UNDER THE DEEP
NORTHWEST FLOW BEHIND THE LOW AND EAST OF THE RIDGE AXIS. AS OF EARLY
AFTERNOON CONVECTION REMAINED NEAR OR WEST OF THE SFC RIDGE AXIS...
OVER PORTIONS OF SD/NEB.
01.12Z MODELS LOOK TO HAVE INITIALIZED WELL...BUT FOR THE GFS WITH
ITS USUAL SFC DEW POINT ANALYSIS BEING OFF A BIT OVER THE UPPER
MIDWEST. DPROG/DT OF 500MB HGTS AT 01.12Z SHOWED THE MODEL RUNS OF
30.12Z AND 31.12Z VERIFIED WELL ACROSS NOAM/EASTERN PAC EVEN WITH THE
SMALLER SCALE FEATURES IN THE FLOW. SOLUTIONS VERY SIMILAR FOR
TONIGHT/FRI...CONVERGING TOWARD A TIGHTER/COMMON CONSENSUS. SOLUTIONS
THEN DIVERGE FOR THE 3RD PERIOD /FRI NIGHT/ WITH THE NAM AGAIN
STRONGER ON A SHORTWAVE DROPPING THRU THE NORTHWEST FLOW TOWARD THE
AREA AND IS MORE ROBUST WITH LIFT/MOISTURE OVER THE AREA. NO ONE
MODE WITH CLEARLY BETTER RUN-TO-RUN CONSISTENCY THAN THE OTHERS.
CHECK OF OBS VS. MODEL DATA AT 18Z SHOWED ALL MODELS WERE QUITE
REASONABLE WITH THE SFC MASS FIELDS OVER THE CENTRAL CONUS. GFS WAS
IMPROVING ON SFC DEW POINTS. PER WV IMAGERY MODELS ALL LOOKED TO
HAVE A GOOD HANDLE ON THE MORE IDENTIFIABLE SHORTWAVES IN THE FLOW
OVER NOAM. MODELS REASONABLE WITH THE 12-18Z PRECIP OVER THE CENTRAL/
NORTHERN PLAINS AND WITH THE SCT SHRA IN FAR NORTHEAST MN/WI.
FAVORED THE MODEL/ENSEMBLE CONSENSUS FOR TONIGHT/FRI. WITH THE
NAM AGAIN APPEARING AS AN OUTLIER FRI NIGHT FAVORED THE NON-NAM
MODEL CONSENSUS. SHORT TERM FCST CONFIDENCE GOOD TONIGHT/FRI THEN
AVERAGE FRI NIGHT.
FOR THE SHORT TERM...MODELS STILL SPREADING SOME 850-700MB MOISTURE
TRANSPORT/THETA-E CONVERGENCE ACROSS ABOUT THE SOUTHWEST THIRD OF
THE FCST AREA TONIGHT/FRI. THE FLOW IS MORE PARALLEL TO THE THERMAL
GRADIENTS THAN IS PERPENDICULAR TO IT...THUS THE OVERALL CONVERGENCE
AND LIFT OF THE AIRMASS STAYS ON THE WEAK SIDE. EVEN MU CAPE OVER
THE SOUTHWEST END OF THE FCST AREA REMAINS ON THE LOW SIDE TONIGHT.
THUS NOT SURE HOW MUCH TSRA THERE WILL BE TONIGHT. WITH THE
CONSISTENCY OF THE MODEL SIGNAL TO PRODUCE SOME PRECIP OVER THE
SOUTHWEST 1/3 OF THE FCST AREA...CONTINUED TO CARRY 20-50 PERCENT
SHRA/TSRA CHANCES OVER ABOUT THE SOUTHWEST 1/2 OF THE FCST AREA.
SOME OF THIS MOISTURE TRANSPORT AND WEAK LIFT CONTINUES TO TRANSLATE
ACROSS THE SOUTH END OF THE FCST AREA FRI...WITH MU CAPES AS HIGH AS
PERHAPS 1K-2K J/KG NEAR THE SOUTH BORDER OF THE FCST AREA FRI
AFTERNOON. CONTINUED MAINLY 20-40 PERCENT SHRA/TSRA CHANCES ACROSS
THE SOUTH 1/3 OF THE FCST AREA FOR FRI. FURTHER NORTH...WITH LESS
MOISTURE OR INCREASE OF MOISTURE AND MORE UNDER THE WEST EDGE OF
THE NORTHWEST FLOW AROUND THE HUDSON BAY LOW/VORTEX...TREND SKY
GRIDS MORE TOWARD CLEAR TO PARTLY CLOUDY TONIGHT/FRI.
BIGGER QUESTIONS ARE FRI NIGHT. AGAIN NAM BRINGS A STRONGER
NORTHWEST FLOW SHORTWAVE TOWARD THE AREA...WHICH HELPS TO GENERATE A
RATHER STRONG LOOKING 850-500MB FN CONVERGENCE BAND NORTHWEST TO
SOUTHEAST ACROSS THE AREA OVER THE AREA BY LATER FRI NIGHT. MUCH OF
THE MOISTURE THE NAM BRINGS LOOKS TO BE IN THE 800-600MB LAYER...
WITH LITTLE IN THE WAY OF INSTABILITY. APPEARS EVEN IF NAM WAS
CORRECT ANY PRECIP MAINLY LATER FRI NIGHT WOULD BE SPRINKLES/-RA
FROM AN 8K-10K FT DECK. NAM HAS SOME MOISTURE TRANSPORT AT 700MB
BUT THIS AGAIN NEARLY PARALLEL TO THE THERMAL GRADIENT. WITH NAM
LOOKING RATHER SUSPECT...LEFT FRI NIGHT DRY PER CONSENSUS OF OTHER
MODELS...WHICH BLENDS WELL WITH ALL NEIGHBORING GRIDS. WOULD EXPECT
AT LEAST SOME SCT/PERHAPS BKN MID CLOUD DECKS AND DID NOT ADD
VALLEY FOG TO THE LATE FRI NIGHT GRIDS FOR NOW.
USED A BLEND OF THE NUMERICAL GUIDANCE LOWS/HIGHS FOR TONIGHT THRU
FRI NIGHT.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 343 PM CDT THU AUG 1 2013
MAIN FORECAST CONCERNS FOR SAT THRU SUN NIGHT...TEMPERATURES SAT
THRU SUN...VALLEY FOG POTENTIAL CENTERED ON 12Z SUN...SHRA/TSRA
CHANCES SUN NIGHT.
MODELS REMAIN IN DECENT AGREEMENT SAT THRU SUN AS HGTS RISE A BIT
OVER THE WESTERN GREAT LAKES AND WEAK SHORTWAVE RIDGING ALOFT BUILDS
IN. BY SUN NIGHT MODELS A BIT AT ODDS WITH TIMING/STRENGTH OF A
SHORTWAVE TO LOWER HGTS AND DROP SOUTHEAST INTO THE UPPER MIDWEST.
GIVEN NO ONE MODEL WITH CLEARLY BETTER RUN-TO-RUN CONSISTENCY THAN
THE OTHERS...SIDED WITH THE MODEL/ENSEMBLE CONSENSUS. FCST
CONFIDENCE THIS PERIOD AVERAGE TO GOOD.
PROBLEMS WITH NAM ADDRESSED FOR FRI NIGHT EXTEND INTO SAT MORNING.
CONTINUED TO DISCOUNT NAM FOR SAT MORNING FOR SAME REASONS AND LEFT
SAT DRY AS HGTS RISE AND CAN HIGH PRESSURE NOSES SOUTHEAST INTO THE
WESTERN GREAT LAKES. LEFT SKIES FOR SAT GENERALLY MOSTLY SUNNY AS
WELL. 850MB TEMPS IN THE +9 TO +12C RANGE...STILL ABOUT 1 STANDARD
DEVIATION BELOW NORMAL. WITH PLENTIFUL SUNSHINE ON SAT...HIGHS
SHOULD CLIMB TO THE MID 70S-NEAR 80...EVEN WITH LIGHT NORTH WINDS
AND THE HIGH SLOWLY BUILDING IN. THE HIGH STILL SETTLES ACROSS
MN/IA/WI FOR SAT NIGHT. DEPENDING ON HOW DEW POINT DROP/DRYING
OCCURS ON SAT...AND RECOVERY IN THE EVENING...SAT NIGHT SHOWING
SIGNS FOR A FAVORABLE RADIATIONAL VALLEY FOG NIGHT. WILL ADD MENTION
OF AT LEAST PATCHY VALLEY FOG TO FCST GRIDS FOR A FEW HOURS
CENTERED ON 12Z SUN. LATEST MODEL SET HAVE ALL EITHER WEAKENED THE
SHORTWAVE DUE TO APPROACH SUNDAY OR DELAYED IT INTO SUN NIGHT...WITH
LITTLE IN THE WAY OF LOWER LEVEL MOISTURE TRANSPORT/INCREASE INTO
THE AREA UNTIL SUN NIGHT. THE DRY CAN HIGH PRESSURE IS NOW EXPECTED
TO HOLD OVER THE AREA THRU SUN. REMOVED THE SMALL SUN AFTERNOON
SHRA/TSRA CHANCES FROM THE WEST END OF THE FCST AREA. EVEN WITH A
WEAKER WAVE TO APPROACH SUN NIGHT...MODEL CONSENSUS CONTINUES WITH
AN INCREASE OF 850-700MB MOISTURE TRANSPORT/PW VALUES INTO THE AREA
SUN NIGHT...MORE SO AFTER MIDNIGHT. LEFT THE MODEL/ENSEMBLE CONSENSUS
ROUGHLY 30 PERCENT SHRA/TSRA CHANCE FOR SUN NIGHT BUT COULD PROBABLY
TRENDED MUCH OF THIS AFTER MIDNIGHT/EARLY MON MORNING.
USED A BLEND OF THE NUMERICAL GUIDANCE HIGHS/LOWS FOR SAT/SUN/SUN
NIGHT. CONTINUED TO TREND TOWARD COOLER OF GUIDANCE LOWS SAT NIGHT
WITH THE DRY/COOL CAN HIGH SETTLING OVERHEAD.
MEDIUM RANGE MODEL RUNS OF 01.12Z AND 01.00Z IN RATHER GOOD AGREEMENT
WITH EACH OTHER AND THEIR 31.00Z RUNS AT THE START OF THE DAY 4-7
PERIOD WITH A CONTINUATION OF THE BLOCKY WEST COAST PATTERN AND
DOWNSTREAM TROUGHING/NORTHWEST FLOW OVER CENTRAL/EASTERN NOAM.
DIFFERENCES SLOWLY EMERGE/GROW FOR TUE-THU WITH SLOW PROGRESSION EAST
OF THE WEST COAST BLOCK AND A SHARPER TROUGH/SHORTWAVE ROTATING
AROUND THE WEST SIDE OF THE EASTERN CAN VORTEX AND DROPPING INTO THE
WESTERN GREAT LAKES BY THU. EVEN WITH THE DIFFERENCES BY THU...FCST
CONFIDENCE REMAINS GOOD THAT TEMPS WILL REMAIN BELOW NORMAL THRU
THE DAY 4-7 PORTION OF THE FCST. THERE WILL BE SHRA/TSRA CHANCES NEXT
WEEK BUT THESE WILL BE DIFFICULT TO TIME DUE TO SHORTWAVE DETAIL
DIFFERENCES AMONG THE MODELS IN THIS TIME FRAME. THUS FCST CONFIDENCE
REMAINS BELOW AVERAGE CONCERNING MON-THU PRECIP CHANCES. FOR NOW
FAVORED THE MODEL/ENSEMBLE CONSENSUS THRU THE PERIOD.
AS THE SFC...THE MON-THU PERIOD LOOKS TO BE DOMINATED BY HIGH
PRESSURE WITH WEAK REFLECTIONS OF THE PASSING MID LEVEL SHORTWAVES.
THE STRONGER TROUGH/SHORTWAVE ROTATING AROUND THE WEST SIDE OF THE
EASTERN CAN VORTEX AND HEADED FOR THE REGION LOOKS TO DRIVE A
STRONGER COLD FRONT SOUTH ACROSS THE AREA TUE NIGHT/WED...WITH MORE
CAN HIGH PRESSURE TO BUILD IN BEHIND IT FOR LATER IN THE WEEK.
APPEARS MUCH OF THE MOISTURE FLUX INTO THE AREA WITH THE PASSING
SHORTWAVES WILL MAINLY BE ABOVE THE SFC...MORE IN THE 850-700MB
LAYER...AS HIGH PRESSURE CONTROLS THE AREA AND LIMITED CONNECTION
TO THE GULF OR SOUTHERN PLAINS MOISTURE. SFC DEW POINTS LOOKING TO
REMAIN IN THE MORE COMFORTABLE 50S TO PERHAPS MID 60S RANGE. THE
CONTINUED NORTHWEST FLOW WILL NOT HELP DEEP MOISTURE RETURN INTO
THE AREA EITHER. THIS WILL LIMIT THE MOISTURE THE PASSING WAVES AND
ROUNDS OF LOWER LEVEL THERMO-DYNAMIC FORCING WILL HAVE TO WORK WITH.
MODEL/ENSEMBLE CONSENSUS SHRA/TSRA CHANCES IN THE 20-30 PERCENT RANGE
MUCH OF THE DAY 4-7 PERIOD LIKELY DUE TO THIS...AND LOOK WELL TRENDED
UNTIL TIMING DETAILS BECOME CLEARER. UNDER THE NORTHWEST FLOW
ALOFT...THEN INCREASING INFLUENCE OF THE EASTERN CAN VORTEX LATE NEXT
WEEK...850MB TEMPS REMAIN AROUND 1 STANDARD DEVIATION BELOW NORMAL
EARLY IN THE WEEK...TRENDING TO 1 TO 2 BELOW NORMAL BY THU/FRI.
DECENT CONFIDENCE FOR MON-THU HIGHS/LOWS TO STAY SOME 1 TO 2
CATEGORIES BELOW NORMAL...EVEN COOLER LATER IN THE WEEK.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1232 PM CDT THU AUG 1 2013
VFR CONDITIONS EXPECTED THROUGH THE FORECAST PERIOD AND THE MAIN
FOCUS IS ON INCREASING MOISTURE SURGE / UPPER LEVEL IMPULSE MOVING
ACROSS THE DAKOTAS INTO WESTERN MINNESOTA. THIS WEATHER SYSTEM IS
LIKELY TO GENERATE SHOWERS AND THUNDERSTORMS ACROSS THAT AREA...THEN
TRACK INTO SOUTHERN MINNESOTA AND IOWA THROUGH THE EVENING. THE
HIGHEST CHANCES LOOK TO REMAIN SOUTH/WEST OF THE TAF SITES...HOWEVER
WILL CONTINUE TO HONOR VCSH GROUP AT KRST FOR A FEW HOURS THIS
EVENING. BROKEN MID LEVEL DECK COULD LINGER THROUGH PARTS OF THE
OVERNIGHT...GIVING WAY TO MOSTLY CLEAR SKIES BY SUNRISE. FOR
FRIDAY...EXPECTING MOSTLY SUNNY SKIES AND LIGHT WEST/NORTHWEST WINDS
AS FRONTAL BOUNDARY REMAINS SOUTH IN IOWA AND HIGH PRESSURE BUILDS IN
FROM THE NORTH.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
UPDATE...BAUMGARDT
SHORT TERM...RRS
LONG TERM....RRS
AVIATION.....ZT
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
1049 PM MDT FRI AUG 2 2013
.UPDATE...
ISSUED AT 1049 PM MDT FRI AUG 2 2013
CONVECTION CONTINUES ALONG THE ROAN PLATEAU IN RESPONSE TO
DISTURBANCE MOVING OVERHEAD. HRRR NOT PICKING THIS UP WELL THOUGH
NAM12 HAS NAILED IT. GUIDANCE SUGGESTS THIS SET OF STORMS WILL
CONTINUE FOR THE NEXT SEVERAL HOURS. CONVECTION ALSO GETTING GOING
AGAIN FOR THE SAN JUANS. RAP40 INDICATING A FAIRLY ROBUST VORT MAX
HEADING NORTHWARD FROM NEW MEXICO AND LIKELY THE CULPRIT FOR
CONVECTION. WENT AHEAD AND UPPED POPS TO KEEP PRECIP IN THE
FORECAST ALL NIGHT AS THIS FEATURE MOVES OVER THE REGION. LOOKS TO
BE ANOTHER FAIRLY ACTIVE NIGHT.
UPDATE ISSUED AT 935 PM MDT FRI AUG 2 2013
MINOR WAVE IN SOUTHWEST FLOW SPARKING A FEW STORMS ACROSS
NORTHEAST UTAH THIS EVENING AND HAVE MADE SOME ADJUSTMENTS TO THE
FORECAST TO BOOST POPS IN THIS AREA FOR THE REMAINDER OF THE
EVENING. PER SLC REPORTS...STORMS BECOMING MORE EFFICIENT RAIN
PRODUCERS WITH SMALL HAIL BECOMING LESS OF A THREAT. FEW CELLS
ALSO HANGING ON ACROSS PORTIONS OF HINSDALE AND ARCHULETA COUNTIES
IN SOUTHWEST COLORADO WHICH WILL BE DISSIPATING OVER THE NEXT FEW
HOURS. GRIDS HAVE BEEN UPDATED AND NEW ZONES WILL BE OUT SHORTLY.
&&
.SHORT TERM...(TONIGHT THROUGH SATURDAY NIGHT)
306 PM MDT FRI AUG 2 2013
00Z H5 HAND ANALYSIS CONTINUES TO SHOW A BLOCKY NORTHERN STREAM IN
THE VICINITY OF THE US/CANADIAN INTERFACE. IN THE EAST TROUGHING IN
THE NORTHEAST CONUS IS PHASED MERIDIONALLY BACK INTO THE ARCTIC
LATITUDES. THIS FEATURE IS BLOCKING A SMALLER BUT PERSISTENT
POSITIVELY TILTED TROF OVER THE NORTHWEST CONUS. BOTH WILL PLAY A
ROLE IN THE WEATHER PATTERN BUT THE WESTERN SYSTEM INTERACTION WITH
THE SUB TROPICAL HIGH OVER THE SOUTHERN PLAINS WILL BE MORE A DRIVER
TO OUR CWA.
GOES DERIVED AND SURFACE BASED PWAT DATA INDICATE AROUND AN INCH OF
PWAT NEAR GJT THIS AFTERNOON WITH THE MUCH DRIER CONDITIONS TO THE
NORTHWEST AND MOISTURE SURGING FROM THE SOUTH. AN AREA OF FASTER
WINDS ALOFT ARE STILL BISECTING OUR CWA FROM SW TO NE AND APPEAR TO
BE POSSIBLE DRIVER TO THE CONVECTION OVER THE NEXT 24 TO 36 HOURS.
STORMS HAVE BEEN SLOW TO FIRE THIS AFTERNOON WITH MUCH BETTER
ORGANIZATION OVER SOUTHEAST ARIZONA THIS AFTERNOON. WE SHOULD
CONTINUE TO SEE STORMS FORMING OVER OUR SOUTHERN CWA TERRAIN THROUGH
THE AFTERNOON...EVENTUALLY FORCING SOME ISOLATED CONVECTION INTO
SURROUNDING VALLEYS. OTHER STORMS MAY ALSO DRIFT OUT THE RED STONE
AREAS OF ARIZONA AND UTAH INTO OUR SOUTHEAST CWA PRIOR TO SUNSET.
EXPECT A DIURNAL DOWNTURN TONIGHT BUT MODELS HAVE BEEN HINTING AT
SOME STORMS LINGERING IN THE WEST ALONG WHERE MOISTURE ADVECTION
UNDERNEATH A SPEED MAX ALOFT COULD KEEP A FEW ISOLATED STORMS
POPPING. NOT CONFIDENT SO POPS REMAIN ISOLATED.
ENERGY WILL BE RELEASING FROM PACIFIC NORTHWEST TROF LATE TONIGHT
AND TRANSVERSING THE RIDGE ON SATURDAY. THIS WILL SLIGHT SHIFT THE
STRONGER WINDS ALOFT EASTWARD WITH SOME DRIER AIR IN THE GREAT BASIN
MOVING BACK INTO OUR EASTERN CWA. THE MOISTURE SEEM POINTED INTO THE
COLORADO MOUNTAINS WITH ADDITIONAL FORCING COMING FROM THE WAVE OF
SOUTHERN ARIZONA TODAY. MODELS TO SEEM TO HAVE TO DEGREE OF FEEDBACK
AS WELL SO THINKING THE MORNING SHOULD AGAIN BE FAIRLY QUIET AND
ADJUSTED POPS TO INCREASE SIGNIFICANTLY IN THE TYPICALLY DIURNAL
FASHION. AT TM THERE IS LITTLE FOCUS FOR THUNDERSTORMS OVERNIGHT SO
WILL KEEP THE TREND OF DECREASING STORMS GOING SATURDAY NIGHT.
TEMPERATURES WILL REMAIN SEASONAL FOR THE AFTERNOON WITH MILDER
NIGHTS WITH THE INFLUX OF MOISTURE.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
306 PM MDT FRI AUG 2 2013
THESE PERIODS BEGIN WITH THE PERSISTENT SUBTROPICAL RIDGE CENTERED
IN TEXAS AND A DEEPENING TROUGH ALONG THE WEST COAST. EARLY NEXT
WEEK...THE INTERACTION OF THE TWO LARGE SCALE FEATURES AMPLIFIES
THE RIDGE AXIS TO THE NW INTO NE OREGON. BY EARLY WEDNESDAY THE
WEST COAST TROUGH COMES ONSHORE AND DEFORMS THE EASTWARD. THE
RIDGE PUSHES BACK A BIT LATE NEXT WEEK. YET NONE OF THIS FULLY
EXPLAINS THE SENSIBLE WEATHER IN STORE FOR THIS FORECAST AREA.
IT IS THE EBB AND FLOW OF MOISTURE FROM THE S-SW...AND SUBTLE
DISTURBANCES THAT ARE THE DRIVERS FOR EARLY AUGUST WEATHER HERE.
SUNDAY...MOISTURE IS SOMEWHAT DIMINISHED WITH PRECIPITABLE WATER
VALUES NEAR ONE INCH IN THE SOUTH DECREASING TO NEAR HALF AN INCH
NORTH. MODELS HAVE HAD GOOD CONSISTENCY FAVORING THE COLORADO
SPINE WITH SCATTERED CONVECTIVE STORMS SUNDAY...WITH LESSER
COVERAGE IN EASTERN UTAH AND FAR WESTERN COLORADO. EXPECT NEAR
NORMAL WARM TEMPERATURES.
MODELS HAVE ALSO SHOWN GOOD CONTINUITY WITH A DISTURBANCE AND
RESULTING MOISTURE SURGE WORKING INTO THE FOUR CORNERS EARLY
MONDAY AND INTO THE NORTHERN ZONES LATE MONDAY OR TUESDAY.
INCREASED THUNDERSTORM ACTIVITY EXPECTED FOR ALL ZONES MONDAY-
TUESDAY WITH THE POTENTIAL FOR HEAVY SHOWERS FAVORING THE SOUTH
WHERE MOISTURE IS DEEPEST AND STORM MOTION IS SLOWEST.
WEDNESDAY-THURSDAY THE APPROACHING TROUGH ADVECTS IN SOME DRY AIR
AGAIN LIMITING CONVECTION. THE GFS LOWERS PRECIPITABLE WATER
VALUES TO 0.4-0.5 INCH FOR THE ENTIRE FORECAST AREA...THOUGH THE
DRIEST AIR WILL LIKELY BE IN THE WESTERN HALF.
STARTING FRIDAY THERE IS SOME HINT IN BOTH THE EC AND GFS THAT
THE MONSOONAL MOISTURE TRIES TO RETURN AT LEAST INTO THE SOUTHERN
ZONES.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 935 PM MDT FRI AUG 2 2013
ISOLATED THUNDERSTORMS PASSING ACROSS NORTHEAST UTAH MAY IMPACT
KVEL UNTIL 08Z THIS MORNING...OTHERWISE VFR CONDITIONS EXPECTED AT
ALL TERMINAL SITES THROUGH 18Z SATURDAY. ANOTHER PUSH OF MOISTURE
WILL WORK THROUGH THE REGION AFTER 18Z...SPARKING ANOTHER ROUND OF
SHOWERS AND THUNDERSTORMS...MAINLY CONFINED TO THE HIGHER TERRAIN.
GUSTY WINDS...BRIEF HEAVY RAINFALL AND SMALL HAIL WILL BE POSSIBLE
WITH CONVECTION SATURDAY AFTERNOON AND EVENING.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...NONE.
UT...NONE.
&&
$$
UPDATE...TGR
SHORT TERM...15
LONG TERM...JOE
AVIATION...JDC
AREA FORECAST DISCUSSION
NWS MIAMI FL
133 AM EDT SAT AUG 3 2013
.AVIATION...A FEW SHOWERS ARE DEVELOPING IN THE VICINITY OF KAPF
SO PLACED VCSH THERE OVERNIGHT. THERE IS A LESSER CHANCE ALONG THE
ATLANTIC COAST EARLY THIS MORNING. SCATTERED SHRA/TSRA IS
EXPECTED TO DEVELOP DURING THE AFTERNOON ACROSS SOUTH FL, SO
PLACED VCTS ALL TERMINALS THEN. IFR IS POSSIBLE AT ANY GIVEN
TERMINAL, BUT IT WOULD BE BRIEF AND CONFIDENCE IS TOO LOW TO PLACE
ANYTHING MORE THAN VCTS FOR THIS AFTERNOON AT THIS TIME. LIGHT-
CALM WINDS THIS MORNING ARE FORECAST TO BECOMING S-SE EAST COAST
(EXCEPT LIKELY REMAINING SW AT KTMB) AND SW AT KAPF AT 5-10 KT.
/GREGORIA
&&
.PREV DISCUSSION... /ISSUED 756 PM EDT FRI AUG 2 2013/
DISCUSSION...
MAIN ADJUSTMENTS TONIGHT ARE JUST FINE TUNING WHERE CONVECTION HAS
FIRED ACROSS SOUTH FLORIDA IN COMPARISON TO WHERE THE MODELS
ORIGINALLY HAD PLACED IT. CURRENT MODELS KEEP MOST OF THE
CONVECTION ALONG THE ATLANTIC COAST, NORTH OF MIAMI. HOWEVER, HAVE
KEPT ISOLATED SHOWERS AND THUNDERSTORM ACROSS SOUTH FLORIDA
THROUGH THE OVERNIGHT HOURS, DUE TO OUTFLOW BOUNDARIES FLOATING
AROUND THROUGHOUT THE CWA. THESE BOUNDARIES COULD ALLOW SOME
ISOLATED SHOWERS AND EVEN A THUNDERSTORM TO POP UP TONIGHT.
OTHERWISE, ONCE THE MAIN LINE THAT IS BEGINNING TO SHOW SIGNS OF
WEAKENING DISSIPATES, THE WEATHER SHOULD BE FAIRLY QUIET ACROSS
SOUTH FLORIDA.
AVIATION...
LINE OF SHRAS/TSRAS IN ASSOCIATION WITH THE REMNANTS OF DORIAN
CONTINUES TO SWEEP ACROSS PORTIONS OF NORTHEASTERN BROWARD COUNTY
AFFECTING KFXE AND KFLL WHERE ISOLATED MVFR/IFR CONDITIONS MAY BE
SEEN BRIEFLY WITHIN TSRAS. LATEST HRRR SHOWS THIS ACTIVITY
WEAKENING GRADUALLY OVER THE NEXT FEW HOURS. LIGHT SOUTHWESTERLY
FLOW SHOULD PREVAIL OVERNIGHT. ANOTHER ROUND OF SHRAS/TSRAS IS
EXPECTED TOMORROW BUT SHOULD BE MAINLY DIURNAL/SEA BREEZE INDUCED
ACTIVITY.
PREV DISCUSSION... /ISSUED 210 PM EDT FRI AUG 2 2013/
SHORT TERM (TONIGHT-SUNDAY NIGHT)...
THE WEAK SURFACE LOW PRESSURE WHICH IS THE REMNANTS OF DORIAN
CONTINUES OFF THE EAST FLORIDA COAST DRIFTING VERY SLOWLY TO THE
NORTH SNEAKING ITS WAY THROUGH A WEAKNESS IN THE MID LEVEL
SUBTROPICAL RIDGE. GLOBAL MODELS IN FAIR AGREEMENT IN LIFTING IT
SLOWLY NORTH TONIGHT AND THEN A GRADUAL SHIFT TO THE NORTH-NORTHEAST
ON SATURDAY AS IT GETS PICKED UP BY A FRONTAL BOUNDARY MOVING ONTO
THE EASTERN SEABOARD. THE DIFFERENCE IN OPINION IS ON JUST HOW THIS
WILL IMPACT THE WEATHER PARAMETERS OVER SOUTH FLORIDA ESPECIALLY
INTO LATE THIS AFTERNOON AND EVENING. SOME OF THE HIGH RESOLUTION
SHORT TERM MODELS ARE PERSISTENT IN DEVELOPING CONVECTION THIS
AFTERNOON AFTER 18Z. HOWEVER, THUS FAR THE WEAK MID LEVEL LAPSE
RATES AS SHOWN IN THE 12Z MFL SOUNDING HAVE HAMPERED THIS
DEVELOPMENT. SO WILL CONTINUE TO MONITOR FOR ANY CHANGES NEEDED TO
BE MADE. DUE TO DEVELOPMENT ALONG THE SEA BREEZES AND CONVECTION
MOVING ALONG THE EASTERN SIDE OF LAKE OKEECHOBEE GETTING CLOSE TO
OUR NORTHEAST ZONES, WILL CONTINUE WITH THE HIGH END POPS FOR NOW.
THE FRONTAL BOUNDARY WILL CONTINUE TO SHIFT EAST INTO THE ATLANTIC
OVER THE WEEKEND AS A DEEPENING TROUGH CONTINUES TO EVOLVE OVER THE
EASTERN U.S. WHILE MAINTAINING THE WEAKNESS IN THE SUBTROPICAL RIDGE
OVER SOUTH FLORIDA. THIS WILL ALSO MAINTAIN A DEEP TROPICAL AIRMASS
ACROSS THE REGION WITHOUT A SYNOPTIC SYSTEM TO PUSH IT OUT OF THE
AREA. FORECAST SOUNDINGS SHOW PWAT CONTINUING TO HOVER AROUND THE 2
INCH MARK. A SURFACE RIDGE WILL ALSO BE STRETCHED ACROSS THE FLORIDA
STRAITS THIS WEEKEND AND THIS WILL RESULT IN A WEAK SOUTHWEST TO
WEST STEERING FLOW FOR SOUTH FLORIDA SO THE CHANCES FOR CONVECTION
WILL BE NEAR AVERAGES FOR EARLY AUGUST WITH THE GREATEST THREAT
BEING THE INTERIOR AND EAST COAST METRO AREAS.
LONG TERM (MONDAY-FRIDAY)...
LOOKING INTO THE MIDDLE TO THE END OF THE WEEK, THE MID LEVEL
RIDGE WILL BUILD BACK IN ACROSS THE AREA WITH AT OR SLIGHTLY BELOW
POP AVERAGES FOR EARLY AUGUST. HOWEVER, BOTH THE GFS AND ECMWF
HAVE BEEN SHOWING A MID LEVEL INVERTED TROUGH ROTATING WEST BELOW
THE RIDGE AXIS AND THE LATEST RUN SHOWS IT A LITTLE STRONGER
REVERTING SOUTH FLORIDA BACK TO DEEP EASTERLY FLOW BY WEDNESDAY
INTO THE END OF THE WEEK. SO FOR NOW, WILL CONTINUE TO SHOW A
BROAD BRUSH CHANCE POP FORECAST FOR THE MAINLAND BUT IT COULD END
UP WITH HIGHER CHANCES FOR THE INTERIOR AND SOUTHWEST COAST.
MARINE...
A RATHER TRANQUIL MARINE FORECAST WITH THE LOW PRESSURE TROUGH
CONTINUING TO MOVE NORTH OF THE LOCAL WATERS OVER THE WEEKEND.
STILL, THERE COULD BE LOCALLY ROUGH SEAS NEAR STRONGER STORMS THAT
MAY MOVE OFF THE MAINLAND.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 78 93 79 91 / 20 40 20 40
FORT LAUDERDALE 79 91 79 91 / 20 30 20 40
MIAMI 78 92 78 92 / 20 40 20 40
NAPLES 77 90 78 91 / 20 30 20 20
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1250 AM CDT SAT AUG 3 2013
.DISCUSSION...
911 PM CDT
EVENING UPDATE:
STRONG SHORTWAVE/MID LEVEL JET STREAK APPARENT ON WATER VAPOR
PUSHING IN FROM IOWA HAS SUSTAINED CONVECTION THAT FORMED ALONG
MOISTURE CONVERGENCE AXIS SOUTH OF INTERSTATE 80. THIS IS IN AN AIR
MASS THAT IS JUICY SOUTH OF COLD FRONT SINKING SOUTHWARD...WITH
PWATS OF 1.82 INCHES AND 1.72 INCHES RESPECTIVELY ON 00Z DVN AND
ILX RAOBS. RESULT HAS BEEN A MUCH NEEDED HEAVY RAIN EVENT FOR MANY
AREAS SOUTH OF INTERSTATE 80. THOUGH EAST-WEST ORIENTATION OF MAIN
BAND IS CONCERNING...PRECLUDING A BIGGER FLOOD THREAT IS DRY
ANTECEDENT CONDITIONS AND THE SLOW BUT STEADY SOUTHWARD PROGRESS.
NONETHELESS...HOURLY RADAR ESTIMATES OF 1 TO 1.5 INCHES PER HOUR
COULD RESULT IN PONDING ON SOME ROADWAYS. PRECIP LOADING IN MOST
INTENSE CORES COULD RESULT IN BRIEF GUSTY WINDS BUT BIGGEST
CONCERN IS THE HEAVY RAINFALL AND FAIRLY FREQUENT CLOUD TO GROUND
LIGHTNING. TO THE NORTH...AREA OF SPOTTY LIGHT RAIN/DRIZZLE WILL
PUSH EASTWARD AND LIKELY FIZZLE WITH TIME. MADE MINOR TWEAKS TO
POPS FOR PART OF THE EVENING AND OVERNIGHT...BUT REMAINDER OF
FORECAST APPEARS TO BE IN GOOD SHAPE...WITH ONLY TWEAKS TO HOURLY
TRENDS FOR TEMPS AND DEWPOINTS.
RC
//PREV DISCUSSION...
248 PM CDT
THIS AFTERNOON AND TONIGHT...
A SURFACE TROUGH IS DRAPED FROM NORTHERN LAKE MICHIGAN SOUTHWEST
ACROSS SOUTHERN WISCONSIN AND INTO NORTHWESTERN ILLINOIS. AGITATED
CU FIELD HAS DEVELOPED OUT AHEAD OF THE TROUGH FROM DOWNTOWN CHICAGO
WEST ACROSS FAR NORTHERN LA SALLE COUNTY AND SOUTHERN LEE COUNTY.
HAVE RECENTLY SEEN THE FIRST RETURNS ON RADAR DEVELOPING IN THIS
AREA WHICH LATEST SPC MESOANALYSIS SHOWS AS AN AXIS OF 1500 J/KG
UNCAPPED MLCAPE. DEEP LAYER SHEAR IS MARGINAL AT THE MOMENT WITH
ABOUT 30 KTS...BUT THIS NUMBER MAY INCREASE AS WE HEAD INTO THE LATE
AFTERNOON AND EARLY EVENING AS MID LEVEL DISTURBANCE CURRENTLY OVER
NORTH CENTRAL IOWA APPROACHES. THIS FEATURE WILL ALSO INCREASE THE
BROAD SCALE ASCENT OVER THE AREA AND SHOULD LEAD TO AN INCREASE IN
THUNDERSTORM COVERAGE AS WELL AS ORGANIZATION. THERE IS CERTAINLY AN
INCREASED CONCERN FOR SEVERE WEATHER WHICH WILL HAVE TO BE MONITORED
OVER THE NEXT SEVERAL HOURS...ESPECIALLY AS WE GET A LITTLE BETTER
MID LEVEL LAPSE RATES OVER THE AREA AND THE AFOREMENTIONED SHEAR.
THE FOCUS SHOULD SHIFT SOUTH THROUGH THE EVENING. THERE WILL
SOME TRAINING ALONG THE BOUNDARY AS IT SAGS SOUTH THIS EVENING
LEADING TO LOCALIZED HEAVY RAIN AMOUNTS...THOUGH LATEST GUIDANCE
HAS SHIFTED THE FOCUS OF THE LOW LEVEL JET FARTHER EAST OF US
OVERNIGHT...SO APPEARS FOR NOW THAT THE THREAT FOR HEAVY RAIN
OVERNIGHT WILL ALSO BE FARTHER EAST.
SATURDAY THROUGH MONDAY...
SURFACE HIGH WILL BUILD SOUTHEAST FROM THE CANADIAN PRAIRIES...OVER
LAKE MICHIGAN SUNDAY...THEN EAST TO THE MID APPALACHIAN RANGE MONDAY
AND SHOULD PROVIDE A RELATIVELY BENIGN PERIOD OF WEATHER. WE DO GET
A GLANCING BLOW OF COOLER H85 AIR WHICH BOTTOMS OUT 8-9C ON
SUNDAY OVER NORTHEAST PORTIONS OF THE CWA. CANNOT COMPLETELY RULE
OUT SOME DIURNALLY DRIVEN AFTERNOON SHOWERS...AND MODELS DO HINT
AT SEVERAL WEAK SHORTWAVE TROUGHS RIDING DOWN THE RIDGE....BUT
SEEMS MORE LIKELY THAT SUBSIDENCE ASSOCIATED WITH MODERATE MID
LEVEL HEIGHT RISES FROM THE H5 RIDGE BUILDING ACROSS THE AREA WILL
LIMIT CU GROWTH. NAM AND GFS SOUNDINGS BOTH INDICATE A SUBSIDENCE
INVERSION SETTING UP AROUND 750 MB THROUGH THE WEEKEND WHICH WILL
LIMIT THE DEPTH OF THE VERTICAL GROWTH AND SHOULD KEEP THE AREA
DRY.
THIS PERIOD WILL SEE TEMPERATURES WELL BELOW SEASONAL NORMS. AS
MENTIONED...H85 TEMPS BOTTOM OUT SUNDAY AND UPPER AIR CLIMATOLOGY
SHOWS THAT 75% OF THE TIME SURFACE TEMPS TOP OUT AT 76 OR COOLER
WITH H85 TEMPS LESS THAN AROUND 9C. THE ECMWF/GEM/GFS ALL SUPPORT
TEMPS IN THE 71-73 FOR CHICAGO AND 73-74 FOR ROCKFORD...THOUGH THE
NAM WITH ITS TYPICAL HIGH BIAS IS SEVERAL DEGREES WARMER. GIVEN THAT
EVEN MOS GUIDANCE IS CALLING FOR MID 70S...AND WE SHOULD CLOUD UP
SOME WITH COLD AIR CU GROWTH...FELT COMFORTABLE DROPPING TEMPS A
COUPLE MORE DEGREES SUNDAY...CLOSER TO THE BLEND OF RAW GUIDANCE.
TUESDAY AND WEDNESDAY...
WITH THE HIGH SHIFTING EAST OF THE AREA...AND LOW PRESSURE DEEPENING
ACROSS THE CENTRAL/NORTHERN PLAINS...RETURN FLOW INTO THE MID
MISSOURI AND MID MISSISSIPPI VALLEYS SHOULD ALLOW UPPER 60 TO LOW 70
DEWPOINTS TO OVERSPREAD THE AREA WITH MODERATE TO STRONG INSTABILITY
DEVELOPING. STRONG WESTERLIES ALOFT COULD SET THE STAGE FOR A SEVERE
WEATHER OUTBREAK SOMEWHERE NEARBY WITH CURRENT MODEL SOLUTIONS
SETTING THE STAGE JUST TO OUR WEST. WHILE IT`S DIFFICULT TO PIN DOWN
A SEVERE WEATHER THREAT THIS FAR OUT...MODELS ARE IN DECENT
AGREEMENT AND WILL HAVE TO WATCH TUESDAY AND WEDNESDAY CLOSELY.
TEMPERATURES SHOULD RETURN TO SEASONABLE...AND IF ANYTHING CURRENT
PROJECTIONS OF LOW 80S MAY BE A BIT TOO COOL. A COLD FRONT IS
PROJECTED TO PUSH OVER THE AREA WEDNESDAY NIGHT.
THURSDAY AND FRIDAY...
MODELS DIVERGE QUITE A BIT ON HOW FAR SOUTH TO PUSH THE FRONTAL
BOUNDARY. THE GFS PUSHES THE FRONT WAY SOUTH INTO THE SOUTHEASTERN
STATES BY FRIDAY WHILE THE ECMWF STALLS THE FRONT OUT INTO SOUTHERN
ILLINOIS WITH PRECIPITATION OVERRUNNING THE BOUNDARY INTO THE
SOUTHERN CWA. WHILE THE NORTH HALF OF THE CWA SHOULD BE DRY EITHER
WAY...SOUTH OF I-80 ITS LESS CERTAIN. GIVEN THAT THE GFS ENSEMBLE
MAINTAINS SOME QPF FARTHER NORTH THAN THE OPERATIONAL RUN...WILL
MAINTAIN SOME CHANCE FOR THUNDERSTORMS ACROSS THE SOUTHERN CWA LATE
IN THE WEEK.
DEUBELBEISS
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 06Z...
* NORTH WINDS BECOMING NORTHEAST AROUND 10 KT BY MID TO LATE
MORNING.
//DISCUSSION...UPDATED 06Z...
A COOL FRONT ACROSS NORTHERN ILLINOIS CONTINUES TO MOVE SOUTH
EARLY THIS MORNING BRINGING NORTHERLY FLOW ACROSS THE TAF SITES.
THIS WILL GRADUALLY SCOUR OUT THE LOW-LEVEL MOISTURE BY DAYBREAK.
THE SURFACE HIGH PRESSURE RIDGE WILL BUILD IN FROM THE NORTHERN
PLAINS THROUGH NORTH CENTRAL IL TODAY. SUCH AN ORIENTATION WILL
ALLOW FOR NORTHERLY WINDS TO TURN MORE NORTHEAST DURING THE
MORNING. THE LAKE INFLUENCE WILL ADD TO THAT NORTHEAST COMPONENT
FOR ORD AND MDW AND MIXING SHOULD ALLOW FOR 10 KT SUSTAINED SPEEDS
FOR MUCH OF THE AFTERNOON AND LIKELY AS EARLY AS LATE MORNING. A
SECONDARY FRONT WILL DROP SOUTH THIS EVE BUT LOSS OF MIXING SHOULD
KEEP SPEEDS PRIMARILY BELOW 10 KT BY 01Z-02Z OR SO...ALTHOUGH THE
FRONT SHOULD HELP TO KEEP THE NNE DIRECTION. BESIDES SOME FEW-
SCT CUMULUS AND CIRRUS TODAY NOT MUCH OF IMPACT EXPECTED CLOUD-
WISE.
//ORD AND MDW CONFIDENCE...UPDATED 06Z...
* HIGH CONFIDENCE IN OVERALL WIND TRENDS AND TIMING OF NE WINDS
REACHING 10+KT TODAY.
//OUTLOOK FOR ORD/MDW FOR 12Z SUNDAY-12Z FRIDAY...UPDATED 00Z...
SUNDAY THROUGH THURSDAY...MAINLY VFR. CHANCE OF TSRA LATE MONDAY
INTO WEDNESDAY.
MTF/RATZER
&&
.MARINE...
232 PM CDT
THUNDERSTORMS WILL PRIMARILY REMAIN OVER THE FAR SOUTHERN END OF THE
LAKE THIS AFTERNOON AND THE STRONGER STORMS MAY PRODUCE GALE FORCE
GUSTS. SOUTHWEST WINDS WILL BECOME NORTH TONIGHT BEHIND A COOL
FRONT...AND NORTH/NORTHWEST WINDS ARE EXPECTED ACROSS THE LAKE
THROUGH SUNDAY. HIGH PRESSURE MOVES OVER THE LAKE SATURDAY...AND
WINDS BECOME SOUTHEAST BY MONDAY MORNING. THE HIGH SHIFTS EAST OF
THE LAKE MONDAY AND ANOTHER LOW IS EXPECTED TO PASS NORTH OF THE
LAKE THROUGH ONTARIO MID NEXT WEEK. GUIDANCE STILL FEATURES
DIFFERENCES ON TIMING OF THE LOW...BUT TUESDAY NIGHT OR WEDNESDAY
LOOKS LIKE THE BEST TIME FRAME. GUIDANCE ALSO SUGGESTS ANOTHER LOW
MOVES IN FROM THE SOUTHWEST NEXT THURSDAY.
JEE
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
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Area Forecast Discussion
National Weather Service Lincoln IL
1109 PM CDT Fri Aug 2 2013
.DISCUSSION...
ISSUED 830 PM CDT Fri Aug 2 2013
Latest surface analysis indicating the cold front pressing south
through north central Illinois this evening...just north of our
forecast area. Scattered showers and thunderstorms were occurring
just ahead of the boundary this evening and the activity was
shifting east and southeast...which should encompass at least
our northeast third of the forecast area this evening into the
overnight hours. Short term models suggest the showers will
gradually decrease in coverage later this evening as the front
shifts further south. Instability not that great with MUCAPEs
of 500-1000 j/kg early this evening with the greater instability
much further to our southwest, over parts of southern Missouri
into SE Kansas. Front should be in close to the I-70 corridor
by 12z Saturday, thus the higher rain chances tomorrow will be
across the southeast. Have already updated the zones earlier
this evening, so other than some adjustments to the sky grids
and hourly temperatures in the grids, no other changes will
be needed that would warrant another ZFP update.
&&
.AVIATION...
ISSUED 1105 PM CDT Fri Aug 2 2013
Main forecast concern this period will be with coverage of
showers and thunderstorms along southward moving cold front
which was now just north of galesburg and henry...but starting
to make a bit more headway thanks to the convection. areas that
do see the showers and isolated thunderstorms may experience
brief mvfr conditions with some of the heavier rainfall, but as it
looks now, those areas will be few and far between. Other concern
will be with some lower cigs immediately behind the cold front
but based on satellite and surface observations, not much showing
up as of yet. Areas that did see some rainfall this evening may
see some patchy mvfr vsbys in fog but any lower cloud cover or
fog will quickly depart by 13z with VFR conditions prevailing for
the remainder of the period. winds will be light southwest ahead
of the cold front, and then turn light northerly behind it late
tonight, and then turn into the northeast at 10 to 15 kts on Sat.
SMITH
&&
.PREV DISCUSSION...
Issued 248 PM CDT Fri Aug 2 2013
Early afternoon surface map showing the cold front had crossed
much of Wisconsin, then extended westward across southern Iowa to
along the Kansas/Nebraska border. Precipitation so far has been
pretty sparse across the area, with just some high-based very
light showers tracking just south of the I-72 corridor.
Subsidence in the wake of morning convection in northern Illinois
actually allowed for a good deal of clearing across southeast Iowa
and northern Illinois, although diurnal cumulus has been filling
in rather quickly the last couple hours. The clearing helped to
get the air more unstable, with CAPE`s of around 2000 J/kg across
the northern third of the state with little cap, as evidenced by
scattered storms forming around 2 pm just ahead of the front from
Moline to Chicago.
The primary forecast concern in the short term is with the
convective chances over the next 18-24 hours. Rain chances in the
longer range are also a concern due to MCS potential through the
first half of next week.
SHORT TERM...Tonight through Sunday...
Morning model runs have significantly struggled with the
convective trends thus far, so confidence in this part of the
forecast is lower than normal. The most recent HRRR model appears
to be closest to reality, and shows that the broken line of
showers and storms to our north will be drifting across areas
along and north of I-74 into the evening. Scattered storms
currently in Missouri should track eastward as well, affecting
the remainder of the forecast area. Precipitable water values of
1.75 to 2 inches should help produce some heavy rain with the
stronger storms. Can`t rule out some gusty winds and hail as well,
but wind shear overall is rather weak in our area and anything
that does approach severe levels should be the pulse type.
Overnight, the NAM and GFS already have the precipitation on the
wane with a faster push to the cold front, while the ECMWF and
Canadian models linger the showers/storms most of the night with a
slower frontal passage. Have gone with the highest PoPs in the
evening, but kept healthy chances over most of the area overnight.
Not too many changes needed for Saturday, as the frontal boundary
should be through most of the area by midday. Have kept the
northwest CWA dry all day, and continued with all areas north of
I-72 dry by afternoon. All precipitation should be out of the area
by early evening, as high pressure builds southeast into the
Midwest, and cooler/less humid air can be expected the rest of the
weekend.
LONG TERM...Monday through Friday...
Upper level pattern looking fairly agreeable among the GFS and
ECMWF models, with initial northwest flow flattening as a strong
cutoff low sinks southward across Manitoba. GFS remains stronger
with the high keeping our area dry into Monday, while the ECMWF
keeps us on the periphery of the MCS track across Missouri. Have
limited any PoPs to the far southwest for Sunday night and even
then just kept them at 20 percent. Next shortwave on Tuesday
should help boot the high eastward, but convection along the Gulf
Coast will help rob some of the return moisture advection for a
time, so have held off on any decent rain chances until Tuesday
night. Getting into midweek, a surface boundary will become quasi-
stationary as it becomes parallel to the upper flow. The model
differences widen at this point, with the GFS pushing the boundary
through us by late Wednesday night and the ECMWF keeping it north
of the area until Thursday evening. The ultimate position and
associated convective chances will come down to timing of fast
moving shortwaves between the upper low and a sprawling upper high
over the southern U.S. For now have favored a bit of a more
southern push with a period of drier conditions Wednesday night
and Thursday with increasing PoPs again after that.
Geelhart
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
1256 AM EDT SAT AUG 3 2013
.SYNOPSIS...
ISSUED AT 351 PM EDT FRI AUG 2 2013
A PAIR OF UPPER LEVEL DISTURBANCES WILL COMBINE WITH A COLD
FRONTAL BOUNDARY TO PRODUCE SHOWERS AND THUNDERSTORMS ACROSS MUCH
OF THE REGION TONIGHT INTO EARLY SATURDAY. THE BELOW NORMAL
TEMPERATURES WILL CONTINUE SUNDAY AND MONDAY BEHIND THIS FRONT
WITH MAINLY DRY CONDITIONS. A WARM FRONT WILL APPROACH THE AREA
TUESDAY BRINGING THE NEXT CHANCE OF SHOWERS AND THUNDERSTORMS.
&&
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 351 PM EDT FRI AUG 2 2013
PRIMARY SHORT TERM FORECAST CONCERN WILL BE ON CONVECTIVE POTENTIAL
TONIGHT INTO EARLY SATURDAY.
SHOWERS AND EMBEDDED THUNDERSTORMS HAVE SHIFTED EAST OF THE FORECAST
AREA THIS AFTERNOON AS ISENTROPIC UPGLIDE HAS WEAKENED THROUGH THE
DAY AND SHIFTED NORTH AND EAST OF LOCAL AREA. WATER VAPOR IMAGERY AT
18Z INDICATING A COUPLE OF SHORT WAVES OF INTEREST FOR TONIGHT/EARLY
SATURDAY. THE FIRST OF THESE SHORT WAVES CONTINUES TO DIG ACROSS THE
ARROWHEAD OF MINNESOTA ACROSS NORTHERN WISCONSIN. ANOTHER SMALLER
SCALE WAVE APPEARS TO BE KICKING OUT OF EASTERN NEBRASKA...WITH SOME
PRONOUNCED VEERING MID/UPPER LEVEL FLOW PER MERRIMAN PROFILER DATA
PAST HOUR BEHIND THIS SHORT WAVE. A 120 KNOT UPPER JET STREAK
DIGGING THROUGH BASE OF NORTHERN GREAT LAKES UPPER TROUGH WILL PLACE
LOCAL AREA INCREASINGLY IN MORE FAVORED RIGHT ENTRANCE REGION BY
LATE EVENING. VISIBLE SATELLITE IMAGERY TRENDS OVER PAST SEVERAL
HOURS HAVE BEEN TOWARD BUILDING CU ALONG PREFRONTAL TROUGH TYPE
FEATURE FROM THE QUAD CITIES INTO NORTHEAST ILLINOIS WHERE SFC DEW
POINTS HAVE POOLED INTO THE UPPER 60S TO AROUND 70. ABOVE MID/UPPER
LEVEL FORCING MECHANISMS SHOULD INTERACT WITH NARROW PREFRONTAL
TROUGH TYPE FEATURE TO INCREASE COVERAGE OF SCATTERED SHOWERS AND
THUNDERSTORMS LATE THIS AFTERNOON ACROSS NORTHEAST ILLINOIS...AND
EVENTUALLY INTO NORTHERN INDIANA/SOUTHERN LOWER MICHIGAN AS LARGER
SCALE FRONTAL RESPONSE SHIFTS INTO THE AREA. RAP INITIALIZATION DATA
DOES INDICATE THE RELATIVE STABLE BUBBLE ACROSS NORTHERN INDIANA
GIVING WAY TO AXIS OF 100 HPA MLCAPES ON THE ORDER OF 1000 J/KG LATE
THIS AFTERNOON.
BASED ON HOW CURRENT SCENARIO SEEMS TO BE UNFOLDING...HAVE NOT MADE
MANY CHANGES TO SCT POPS TRANSITIONING TO LIKELY POPS EARLY THIS
EVENING ESPECIALLY SOUTHERN HALF AS FRONTAL CIRCULATION BEGINS TO
MATURE. EXPECTING SCATTERED CONVECTION TO GENERALLY MERGE INTO
LARGER AREA OF RAIN AND EMBEDDED THUNDERSTORMS AS THIS OCCURS. SOME
DECENT RAINFALL AMOUNTS POSSIBLE ESPECIALLY SOUTHERN HALF GIVEN
MOISTURE POOLING ALONG THE FRONT AND INCREASING FRONTOGENETIC
RESPONSE LATER THIS EVENING. A FEW STRONGER CELLS ARE POSSIBLE LATE
AFTERNOON/EARLY EVENING THROUGH ABOUT 00Z ACROSS ESPECIALLY WESTERN
HALF GIVEN FAIRLY ROBUST DEEP LAYER SHEAR...BUT OVERALL SEVERE
THREAT SHOULD REMAIN ISOLATED DUE TO MARGINAL INSTABILITY PROFILES.
GENERALLY UTILIZED SREF IDEA FOR TIMING FRONTAL PROGRESSION INTO
SATURDAY MORNING WHICH LARGELY SUPPORTS GOING FORECAST SO NO
SIGNIFICANT CHANGES MADE TO SATURDAY POPS WITH BULK OF PRECIP
SHIFTING SOUTH OF THE AREA LATE MORNING.
&&
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 351 PM EDT FRI AUG 2 2013
BRIEF RETURN TO TRANQUIL WEATHER EXPECTED FOR EARLY NEXT WEEK.
SHORTWAVE RIDGING/SUBTLE MIDLEVEL HEIGHT RISES AND ANTICYCLONIC LOW
LEVEL FLOW WILL BRING DRY CONDITIONS BEGINNING SATURDAY NIGHT AS THE
COLD FRONT EXITS OUR AREA. LIGHT NORTHERLY WINDS/CAA AND DECREASING
CLOUDS SHOULD ALLOW FOR A COOL NIGHT WITH LOWS DROPPING INTO THE LOW
TO MID 50S PER CONSENSUS OF LATEST RAW AND STATISTICAL GUIDANCE.
STRONG NEGATIVE THETA-E ADVECTION WILL LEAD TO MOSTLY SUNNY SKIES ON
SUNDAY WITH JUST ENOUGH BOUNDARY LAYER MOISTURE SEEN IN FORECAST
SOUNDINGS TO SUPPORT A FEW DIURNAL CU. 850MB TEMPS ALSO DROP INTO
THE SINGLE DIGITS BUT AMPLE SUN SHOULD PUSH AFTERNOON TEMPS INTO THE
MID 70S FOR MOST LOCATIONS. SURFACE HIGH WILL DRIFT OVERHEAD BY
SUNDAY NIGHT WITH ANOTHER COOL NIGHT IN THE LOW 50S EXPECTED. A FEW
AREAS IN OUR NORTHEAST MAY EVEN TOUCH UPPER 40S IF MIDLEVEL CLOUDS
HOLD OFF LONG ENOUGH. SLIGHT MODERATION OF CANADIAN AIRMASS WILL
ALLOW TEMPS ON MONDAY TO CLIMB A DEGREE OR TWO HIGHER BUT STILL ONLY
MID TO UPPER 70S AT BEST.
BY THE MIDDLE OF NEXT WEEK A PIECE OF ENERGY IS EXPECTED TO BREAK
OFF THE POLAR VORTEX AND PHASE WITH THE PERSISTENT HUDSON BAY CLOSED
LOW...ESTABLISHING A DEEP PV ANOMALY THAT IS EXPECTED TO MEANDER
ACROSS SOUTHERN CANADA FOR MUCH OF NEXT WEEK. MEANWHILE...SEVERAL
WEAK SHORTWAVES EMANATING FROM THE NORTHWEST CONUS TROUGH WILL BE
SHEARED ACROSS THE GREAT LAKES IN FAST WNW FLOW ALOFT ON THE SOUTH
SIDE OF AFOREMENTIONED ANOMALY. RETURN FLOW ON THE BACKSIDE OF
DEPARTING SURFACE HIGH WILL ALSO BEGIN TO ADVECT A SLIGHTLY WARMER
AND MORE MOIST/UNSTABLE AIRMASS BACK INTO THE REGION DURING THIS
TIME. NEEDLESS TO SAY NUMERICAL GUIDANCE IS STRUGGLING WITH THE
EVOLUTION OF THIS PATTERN. LATEST 12Z GFS IS CONTINUING TO TREND
TOWARD THE MORE CONSISTENT ECMWF IN SHOWING THE BEST PRECIP
POTENTIAL HOLDING OFF UNTIL LATE TUESDAY AND INTO WEDNESDAY BUT
CONTINUES TO SHOW SIGNIFICANT DIFFERENCES BY LATE IN THE WEEK.
CERTAINLY COULD BE A FEW SCATTERED SHOWERS FROM WAA/ISENTROPIC
ASCENT ON TUESDAY BUT WILL HIGHLIGHT WEDNESDAY WITH THE HIGHEST POPS
AS THE MAIN SHORTWAVE/COLD FRONT PUSH THROUGH THE REGION. WILL LEAVE
THE END OF THE WEEK DRY FOR NOW UNTIL THE MODELS GET A BETTER HANDLE
ON EVOLUTION OF DEEP CANADIAN VORTEX. SLIGHTLY WARMER TEMPS EXPECTED
NEXT WEEK IN SOUTHWEST FLOW AHEAD OF FRONT BUT STILL HOVERING NEAR
TO EVEN SLIGHTLY BELOW NORMAL FOR EARLY AUGUST.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1255 AM EDT SAT AUG 3 2013
COLD FRONT WILL SLIDE SOUTHEAST THROUGH SBN BY 9-10Z AND FWA AROUND
11-12Z. SHOWERS...MORE WIDESPREAD AT FWA...CAN BE EXPECTED BEFORE
THE FRONTAL PASSAGE AS WELL PRONOUNCED MID LEVEL SHORTWAVE DROPS
THROUGH THE AREA IN NW FLOW ALOFT. FLIGHT CONDITIONS AT FWA WILL
LIKELY OSCILLATE BTW IFR/MVFR AHEAD/ALONG OF THE FRONT...MAINLY
MVFR/VFR AT SBN. POST FRONTAL ADVECTION OF DRIER NEAR SFC AIR WILL
BE SOMEWHAT DELAYED WHICH MAY RESULT IN SLOWER EROSION OF BR/CIGS
AT MAINLY FWA. THEREAFTER (DAYBREAK AT SBN AND MID MORNING FWA)...
WEAK DRY/COOL ADVECTION IN DEVELOPING NORTHERLY FLOW WILL RESULT
IN VFR CONDITIONS.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...NONE.
&&
$$
SYNOPSIS...MARSILI
SHORT TERM...MARSILI
LONG TERM...AGD
AVIATION...STEINWEDEL
VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.NORTHERNIN.GOV
WWW.TWITTER.COM/NWSIWX
WWW.YOUTUBE.COM/NWSNORTHERNINDIANA
AREA FORECAST DISCUSSION
NWS PADUCAH KY
1157 PM CDT Fri Aug 2 2013
.UPDATE...
ISSUED AT 1157 PM CDT FRI AUG 2 2013
The aviation section has been updated for the 06Z TAF issuance.
&&
.SHORT TERM...(This Evening through Sunday night)
ISSUED AT 204 PM CDT FRI AUG 2 2013
A mid level wave was seen on satellite and via radar moving across
west Missouri. Convection has formed with this wave and was moving
east. Question is, how far east will it travel over the next
several hours, as it encounters drier air across the region. Will
gradually increase pops through the night. None of the models seem
to have a good handle on convective trends. The latest RAP model
is probably closest. Given low confidence in the latest solutions,
will not stray too far from persistence.
Even after a morning chance of convection, the probability for
more development will persist as a frontal boundary sags south
through the area late. Then, will decrease PoPs from north to
south Saturday night and focus them over the west and south into
Sunday and Sunday night.
Temperatures will be a combination of the latest MAV/MET MOS and
a blend of raw model output.
.LONG TERM...(Monday through Friday)
ISSUED AT 204 PM CDT FRI AUG 2 2013
For the beginning of the extended forecast period, namely Monday and
Tuesday, there has been a little less confidence on the eastward
extent of measurable PoP`s. During the last three days, attempted to
highlight the southwestern part of the WFO PAH county warning area,
namely southeast Missouri for rain chances. The low level surface
winds/moisture convergence appears pinned to southeast Missouri
through at least 12z (7am CDT) Tuesday. Although the SREF, GFS, and
ECMWF model precipitation parametrization schemes vary, the low
level frontal zones are similar during the aforementioned time
period. Given the lack if identifiable and consistent vorticity
advection above the frontal boundary, the decision was to limit the
precipitation chances close to the boundary, plus or minus 50 nm.
By late Tuesday night into Wednesday, the southern plains ridge
builds northward, shifting and sharpening the baroclinic zone and
frontal boundary further to the north. With this in mind, the higher
rain chances are shifted into southern Illinois, southwest Indiana,
and west Kentucky. This pattern remains intact through at least
Wednesday afternoon, when the upper ridge begins to flatten and
shift eastward across the lower Mississippi River valley. This
subtle pattern change, combined with a sharper meridional gradient
flow in the faster west to east flow, should lead to a much greater
tightening of the frontal boundary through the WFO PAH forecast area
next Thursday into Friday. Attempted to show a southward shift in
focus of higher PoP`s into toward the Arkansas and Tennessee borders
during this time period. It is also at this time that the highest
PoPs in the extended forecast period should be expected in the WFO
PAH forecast area.
Tuesday through next Friday will likely see max/min temperatures
approach or tie normals for this time of year, as the forecast area
is fully enveloped in the warm sector. With variable cloud cover,
heat index values should remain in check for most of next week. The
only exception may be next Wednesday afternoon, when heat index
values around 100 degrees may be possible along the southern border
counties of southeast Missouri.
&&
.AVIATION...
ISSUED AT 1157PM CDT FRI AUG 2 2013
The best signal in the latest guidance keeps any significant
convection west of the TAF sites through the overnight hours, and
does not develop convection over the area during the day. Will
therefore keep the forecast dry. The light rain over KOWB should
move off to the east by the beginning of the period.
Satellite imagery indicates that skies actually are beginning to
clear over much of the area, especially at KCGI. Guidance does
indicate more cloud cover over much of the area toward morning,
but not necessarily over KCGI, so decided to throw in a TEMPO
group for MVFR fog there toward sunrise.
The other concern is the potential of MVFR ceilings developing
through the day Saturday as the weak cold front tries to push
through the region. See some currently to the north, closer to
the front, so will add in a prevailing MVFR ceiling over most of
the area beginning mid to late morning and continuing into the
early afternoon. Figure that the ceilings will lift into VFR
territory in the afternoon, but some guidance keeps the MVFR
ceilings in through the afternoon and possibly into the evening,
especially at KEVV and KOWB.
Light south winds will veer to west as the front approaches in the
morning, and then shift closer to due north behind the front by
evening.
&&
.PAH WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
MO...NONE.
IN...NONE.
KY...NONE.
&&
$$
UPDATE...DRS
SHORT TERM...Noles
LONG TERM...Smith
AVIATION...DRS
AREA FORECAST DISCUSSION
NWS DULUTH MN
303 AM CDT SAT AUG 3 2013
.SHORT TERM.../THROUGH TONIGHT/
AT 300AM/0800Z...SURFACE HIGH PRESSURE WAS CENTERED OVER CENTRAL
SASKATCHEWAN AND MANITOBA. THE AXIS OF A MID/UPPER LEVEL RIDGE
STRETCHED ACROSS THE WESTERN PLAINS. A SHORTWAVE NEAR THE
MONTANA/NORTH DAKOTA BORDER WAS MOVING EAST AS IT ROUNDED THE
RIDGE...AND IT WAS BRINGING BKN/OVC MID/UPPER LEVEL CLOUDS ACROSS
NORTH DAKOTA INTO NORTHERN MINNESOTA. A MID/UPPER LEVEL LOW WAS
NEAR SW HUDSON BAY. BKN/OVC LOW CLOUDS COVERED MUCH OF NORTHERN
ONTARIO...BUT WERE SLOWLY APPROACHING THE CANADA/MINNESOTA BORDER.
MOST OF THE NORTHLAND HAD CLEAR SKIES EXCEPT FOR THE WESTERN
FORECAST AREA DUE TO THE FEW/SCT MID/UPPER LEVEL CLOUDS ASSOCIATED
WITH THE APPROACHING SHORTWAVE BEGINNING WORKING THEIR WAY INTO
THE NORTHLAND. THE SURFACE WINDS WERE NEARLY CALM OR VERY LIGHT
FROM THE WNW. TEMPERATURES RANGED FROM THE MID 40S TO LOW 50S.
TODAY...THE CENTER OF THE SURFACE HIGH PRESSURE IN CANADA WILL
MOVE INTO THE RED RIVER VALLEY REGION BY LATE THIS AFTERNOON. THE
NORTHLAND CAN EXPECT PARTLY SUNNY SKIES. THERE WILL BE SOME
MID/UPPER LEVEL CLOUDS ASSOCIATED WITH THE SHORTWAVE IN NORTH
DAKOTA THAT WILL CUT ACROSS NORTHERN MINNESOTA THIS MORNING...AS
WELL AS SCATTERED CUMULUS THAT WILL DEVELOP BY LATE THIS MORNING
DUE TO THE LOW CONVECTIVE TEMPERATURES IN THE COOL NW FLOW. HIGH
TEMPERATURES SHOULD RANGE FROM THE UPPER 60S TO MID 70S.
TONIGHT...THE CENTER OF THE HIGH PRESSURE SYSTEM WILL MOVE THROUGH
THE NORTHLAND. THIS WILL BRING CALM WINDS AND CLEAR SKIES TO THE
REGION. THERE COULD BE PATCHY FOG...BUT SINCE THE SOUNDINGS AND
MODEL FORECAST SURFACE CONDENSATION PRESSURE DEFICITS DO NOT
PROVIDE ENOUGH SUGGESTION OF FOG...I LEFT IT OUT OF THE FORECAST
AT THIS POINT. THE DAY SHIFT MAY NEED TO ADD PATCHY FOG TO THE
FORECAST. OVERNIGHT LOWS SHOULD BE IN THE LOW TO UPPER 40S ACROSS
MOST OF THE REGION. I WOULD NOT BE SURPRISED IF ISOLATED LOCATIONS
ACROSS NORTHERN MINNESOTA GET INTO THE UPPER 30S.
.LONG TERM.../SUNDAY - FRIDAY/
THE AREA OF HIGH PRESSURE WILL
BRING ANOTHER DAY OF QUIET CONDITIONS ACROSS THE REGION ON SUNDAY.
THE NEXT SHOT OF PRECIPITATION WILL COME MONDAY THROUGH TUESDAY
WHEN A LOW PRESSURE CENTER MOVES THROUGH SOUTHERN CANADA ALONG
WITH A SHORTWAVE THAT MOVE THROUGH NRN MN MONDAY AND TUESDAY
MORNING WHICH WILL BRING SHOWERS AND THUNDERSTORMS TO THE FORECAST
AREA. THERE WILL BE BREAK TUESDAY MORNING BEFORE THE LOW DRAGS A
FRONT THROUGH THE REGION TUESDAY AFTERNOON AND EVENING BRINGING
ANOTHER CHANCE FOR THUNDERSTORMS. AFTER THE FRONT PASSES...COOLER
THAN NORMAL TEMPS WILL FLOW INTO THE REGION FOR THE REST OF THE
WEEK WITH LITTLE PRECIPITATION EXPECTED THROUGH THE PERIOD.
&&
.AVIATION.../06Z TAF ISSUANCE/
MAINLY VFR CONDITIONS WILL OCCUR THROUGH THE PERIOD. THERE MAY BE
SOME PATCHY FOG TONIGHT WITH VSBYS DROPPING TO IFR...AND WE HAVE
THAT IN THE KBRD/KHIB/KHYR TAFS ATTM. BROKEN CEILINGS FROM 5-8KFT
WILL BE POSSIBLE OVER THE ARROWHEAD AND BORDER REGION
TONIGHT...BUT BOTH THE RAP AND NAM SUGGEST IT WILL BE MOSTLY
SCATTERED BY LATE TONIGHT. WE EXPECT MORE SCATTERED TO BROKEN VFR
CUMULUS TO FORM ON SATURDAY WITH SOME HEATING.
&&
.POINT TEMPS/POPS...
DLH 72 50 74 50 / 0 0 10 10
INL 69 42 72 49 / 0 0 10 10
BRD 74 49 75 57 / 0 0 10 30
HYR 73 44 73 52 / 0 0 10 10
ASX 73 47 74 51 / 0 0 10 10
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
LS...NONE.
&&
$$
SHORT TERM...GROCHOCINSKI
LONG TERM....STEWART
AVIATION...STEWART
AREA FORECAST DISCUSSION
NWS DULUTH MN
1242 AM CDT SAT AUG 3 2013
.AVIATION...MAINLY VFR CONDITIONS WILL OCCUR THROUGH THE PERIOD. THERE MAY BE
SOME PATCHY FOG TONIGHT WITH VSBYS DROPPING TO IFR...AND WE HAVE
THAT IN THE KBRD/KHIB/KHYR TAFS ATTM. BROKEN CEILINGS FROM 5-8KFT
WILL BE POSSIBLE OVER THE ARROWHEAD AND BORDER REGION TONIGHT...BUT
BOTH THE RAP AND NAM SUGGEST IT WILL BE MOSTLY SCATTERED BY LATE
TONIGHT. WE EXPECT MORE SCATTERED TO BROKEN VFR CUMULUS TO FORM ON
SATURDAY WITH SOME HEATING.
&&
.PREV DISCUSSION... /ISSUED 635 PM CDT FRI AUG 2 2013/
UPDATE...
AREA RADARS SHOW NO RETURNS OVER OUR CWA...WITH A FEW ECHOES THAT
MAY SLIDE BETWEEN THE TIP OF THE ARROWHEAD AND THUNDER BAY OVER
THE NEXT COUPLE HOURS. WE REMOVED POPS FROM THE ARROWHEAD THIS
EVENING AND MADE SOME ADJUSTMENTS TO CLOUD COVER.
AVIATION...00Z TAFS
SCATTERED TO BROKEN CUMULUS SHOULD DISSIPATE ACROSS MUCH OF THE
CWA THIS EVENING...WITH A MORE SOLID DECK OF CLOUDS MOVING SOUTH
OUT OF ONTARIO THAT MAY IMPACT THE ARROWHEAD TONIGHT. THERE WILL
ALSO BE SOME HIGH CLOUDS MOVING THROUGH OVERNIGHT.
SOME PATCHY FOG WILL BE POSSIBLE OVERNIGHT...AND WE CONFINED THE
MENTION TO KHYR/KHIB FOR NOW.
MORE SCATTERED TO BROKEN VFR CUMULUS SHOULD FORM ON SATURDAY.
PREV DISCUSSION... /ISSUED 330 PM CDT FRI AUG 2 2013/
CURRENT...LATEST RAP40 SHOWS JET MAX ASSOCIATED WITH HUDSON BAY
TROF IS MOVING EAST OF REGION SIGNALING THE BEGINNING OF A
TRANSITION TO DRY WEATHER. THE EXCEPTION IS OVER THE ARROWHEAD
THIS AFTN WHERE PROXIMITY TO THE DEPARTING UPPER THERMAL TROUGH IS
GENERATING INSTABILITY RW. ELSEWHERE SCT/BKN CU IS WIDESPREAD AS
RESIDUAL MOISTURE IS LIFTED IN BDRY LYR. CANOPY OF HIGH LVL CIRRUS
CLOUDS MOVING ACROSS SRN CWA IS CONVECTIVE DEBRIS FROM STORMS OVER
NRN PLAINS.
TONIGHT/TOMORROW...AS UPPER TROF MOVES EAST ACROSS ONTARIO A LARGE
SFC HIGH WILL BEGIN ITS MOVE FROM MANITOBA INTO THE REGION. ANY
SHOWER ACTIVITY OVER THE ARROWHEAD WILL DIMINISH THIS EVENING. MDLS
SUGGEST A LOW PROB OF RW TOMORROW OVER ERN ARROWHEAD BUT HAVE KEPT
INHERITED DRY FCST FOR NOW. MIXING LAYER DEEPENS TO AROUND 5K
SATURDAY SO WE MAY STILL HAVE OCCASIONAL GUSTS IN THE AFTERNOON.
TEMPS WILL REMAIN BELOW CLIMO THIS PERIOD.
LONG TERM...SATURDAY NIGHT THROUGH THURSDAY...
MID LEVEL RIDGING WITH SFC HIGH PRESSURE WILL BUILD INTO THE WESTERN
GREAT LAKES REGION LATE SAT THROUGH SUN. THE SFC HIGH WILL BRING
GENERALLY QUIET CONDITIONS WITH BELOW NORMAL TEMPERATURES AND LIGHT
WINDS. CLEAR SKIES AND LIGHT WINDS SUNDAY NIGHT ARE EXPECTED TO
ALLOW OVERNIGHT LOWS TO DIP INTO THE LOW 40S...TO EVEN A FEW UPPER
30S NEAR DAYBREAK SUNDAY. THE MEX GUIDANCE FOR KHIB OVER THE PAST
SEVERAL RUNS HAS CONSISTENTLY SHOWN A LOW TEMP OF 38 F SUNDAY
MORNING.
FOCUS TURNS TO A LONG WAVE TROUGH THAT DROPS ACROSS THE DAKOTAS
MONDAY...BRINGING INCREASING SHOWER AND TSTORM CHANCES TO MN AND NRN
WI MON NIGHT THROUGH TUES NIGHT. HAVE SLOWED TIMING FOR THE POPS AS
LATEST ECM/GFS RUNS CONTINUE TO BACK OFF ON THE PROGRESSION OF THE
WAVE. THE TIMING MAY HAVE TO CONTINUE TO BE REFINED BUT FOR NOW HAVE
KEPT BROADBRUSH CHC POPS MONDAY/MON NIGHT DUE TO INSTABILITY AHEAD
OF THE FRONT. BEST CHANCE FOR STORMS IN THE NORTHLAND WILL ARRIVE
WITH A FRONTAL PASSAGE TUESDAY AFTERNOON/EVENING.
EXTENDED...LONG RANGE MODELS ARE SHOWING A COLD CORE LOW
SETTLES OVER MANITOBA MID-WEEK...THEN GRADUALLY SHIFTS EAST ALONG
THE CANADIAN BORDER INTO THE WEEKEND. ALTHOUGH HIGHLY DEPENDENT ON
THE TRACK POSITION...THERE IS GOOD AGREEMENT H85 TEMPS FALL INTO THE
LOWER SINGLE DIGITS WITH THIS LOW...LEADING TO WELL BELOW NORMAL
TEMPS AND CLOUDS INTO THE WEEKEND.
&&
.POINT TEMPS/POPS...
DLH 48 74 50 71 / 0 10 10 20
INL 43 72 48 73 / 0 10 10 10
BRD 47 75 53 75 / 0 10 30 30
HYR 46 75 51 73 / 0 10 10 30
ASX 48 74 51 72 / 0 10 10 20
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
LS...NONE.
&&
$$
SHORT TERM...GROCHOCINSKI
LONG TERM....STEWART
AVIATION...STEWART
AREA FORECAST DISCUSSION
NWS RALEIGH NC
305 AM EDT SAT AUG 3 2013
.SYNOPSIS...
AS A WEAK FRONT LIES OVER THE AREA...ANOTHER...STRONGER COLD FRONT
APPROACHES FROM THE NORTHWEST. THIS FRONT WILL PASS THROUGH THE
REGION SUNDAY. HIGH PRESSURE BUILDS IN BEHIND THE FRONT MONDAY
BEFORE MOVING OFF THE MID-ATLANTIC COAST TUESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 305 AM SATURDAY...
LINGERING...WEAK SURFACE BOUNDARY REMAINS OVER CENTRAL NORTH
CAROLINA...AND IN VICINITY OF THE BOUNDARY AND THE INSTABILITY
GRADIENT NOTED ON THE SPC MESOANALYSIS...ISOLATED SHOWERS CONTINUED
EARLY THIS MORNING. THE 00Z UPPER-AIR ANALYSIS ALSO SHOWED A PARADE
OF 700MB SHORTWAVES MOVING TOWARD THE AREA IN THE NORTHWEST FLOW
ALOFT...AND THE LATEST HRRR WRF NOTES A FEW SHOWERS LINGERING
THROUGH DAWN IN CENTRAL NORTH CAROLINA. FOLLOWING THIS...THE 850MB
THETA-E RIDGE PERSISTS OVER CENTRAL NORTH CAROLINA THROUGHOUT THE
DAY IN VICINITY OF THE REMNANT BOUNDARY. ALTHOUGH JET SUPPORT IS
WELL NORTH AND NORTHWEST AND OVERALL LIFT IS FORECAST TO BE MODEST
AT BEST ON THE GFS...INSTABILITY OF AROUND 1500J/KG DURING THE
AFTERNOON SHOULD BE ENOUGH TO RESULT IN SCATTERED SHOWERS AND
THUNDERSTORMS PER A BLEND OF THE MAV AND MET MOS GUIDANCE...AND THE
CONSENSUS OF THE HIGH-RESOLUTION MODEL OUTPUT. THE CONSENSUS OF THAT
OUTPUT CERTAINLY PLACES THE HIGHER POTENTIAL FOR SCATTERED SHOWERS
AND THUNDERSTORMS IN VICINITY OF INTERSTATE 95...AND WILL SHOW THE
HIGHER CHANCES THERE FOR TODAY RELATIVE TO THE REST OF CENTRAL NORTH
CAROLINA...AGAIN CLOSER TO THE REMNANT BOUNDARY AND IN DEEPER
MOISTURE. IF THERE WAS FORECAST STRONGER LOW-LEVEL CONVERGENCE...
SHEAR...OR DIFFLUENCE ALOFT THERE MAY BE MORE CONFIDENCE IN NOTING
THE POTENTIAL FOR A LOCALLY SEVERE STORM IN THE HWO...BUT THESE
PARAMETERS ARE FORECAST TO BE SOMEWHAT WEAK ON THE GFS...THOUGH THE
0-3KM SHEAR APPROACHING 25KT IS BETTER THAN WHAT HAS BEEN NOTED IN
RECENT DAYS. WILL LIKELY NOTE THE POTENTIAL FOR A STRONG STORM IN
THE OUTLOOK...KEEPING IN MIND AN ISOLATED SEVERE STORM OR TWO CANNOT
BE COMPLETELY RULED OUT.
OVERNIGHT...A MAXIMUM OF INSTABILITY FORECAST BY THE GFS WEST OF THE
YADKIN RIVER...IN ADVANCE OF AN INCREASE IN POTENTIAL VORTICITY ON
THE 1.5 PVU SURFACE LATE THIS AFTERNOON AND THIS EVENING...MAY HELP
PROVIDE FOR SCATTERED SHOWERS AND THUNDERSTORMS MOVING INTO CENTRAL
NORTH CAROLINA FROM THE WEST...AND LINGERING INTO THE OVERNIGHT
HOURS EAST OF U.S. 1 AND INTO THE INTERSTATE 95 CORRIDOR. HIGHS
TODAY AROUND 90 MOST LOCATIONS WITH PARTLY SUNNY CONDITIONS ON
AVERAGE. OVERNIGHT LOWS TONIGHT UPPER 60S TO MID 70S NORTH TO SOUTH.
&&
.SHORT TERM /SUNDAY AND SUNDAY NIGHT/...
AS OF 305 AM SATURDAY...
A COLD FRONT APPROACHES FROM THE NORTH AND MOVES THROUGH CENTRAL
NORTH CAROLINA DURING THE DAY SUNDAY. IN ADVANCE OF WHAT APPEARS TO
BE THE TRUE FRONT...WINDS SHOULD VEER NORTHWEST THEN BECOME MORE
TRUE NORTH OR NORTH-NORTHEAST BEHIND THE FRONT. THE 850MB FRONT
LINGERS AND IS NOT FORECAST BY THE GFS TO MOVE THROUGH CENTRAL NORTH
CAROLINA UNTIL THE EARLY AFTERNOON. THETA-E RIDGING AT 850MB SHIFTS
SOUTH ALONG WITH HIGHER VALUES OF K INDICES...AND BY AFTERNOON THE
BEST UPPER-LEVEL DIVERGENCE IS FORECAST SOUTH OF THE STATE ACROSS
SOUTH CAROLINA...WHERE THE GFS IS FAIRLY AMPLE WITH THAT PARAMETER
DURING THE AFTERNOON. BUFR SOUNDINGS SHOW INCREASING STABILITY...
ALTHOUGH THE GFS BUFR SOUNDINGS AT KFAY AND KRWI ARE CLOSER TO THE
MOIST ADIABAT IN THE TEMPERATURE PROFILE INTO SUNDAY AFTERNOON.
BESIDES THE POTENTIAL FOR AN ISOLATED SHOWER SUNDAY MORNING...IT MAY
BE DIFFICULT TO GET ANY PRECIPITATION ALONG AND NORTH OF U.S. 64
SUNDAY. CLOSER TO THE SOUTH CAROLINA BORDER...UNTIL THE 850MB FRONT
GOES THROUGH WITH ITS ASSOCIATED LIFT...AND WHILE DEW POINTS ARE
STILL AT LEAST IN THE MID 60S...AN ISOLATED-TO-SCATTERED SHOWER OR
STORM REMAINS POSSIBLE. MLCAPE IN THE LOWEST KM IS HIGHER THERE THAN
ELSEWHERE...AND DCAPE IS AT LEAST 1000J/KG IN THE FAR SOUTH
SUNDAY...WITH INCREASING SHEAR MAKING A STRONG STORM POSSIBLE THERE
IF ONE CAN DEVELOP. BY SUNSET...THIS POTENTIAL SHOULD BE LOCATED
SOUTH OF CENTRAL NORTH CAROLINA ALTOGETHER. AFTER HIGHS SUNDAY FROM
THE UPPER 80S TO LOWER 90S...OVERNIGHT LOWS IN THE DRIER AIR SHOULD
BE IN THE 60S...APPROACHING 60 ESPECIALLY NORTH OF U.S. 64.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
AS OF 255 AM SATURDAY...
HIGH PRESSURE WILL MOVE ACROSS THE MID ATLANTIC REGION ON MONDAY...
MOVING OFFSHORE BY 00Z TUE AS A MID LEVEL SHORT WAVE EMBEDDED IN THE
NW FLOW MOVES SE ACROSS THE MIDWEST. A DRY AIRMASS OVER THE STATE
EARLY MONDAY...PER FORECAST SOUNDINGS WHICH SHOW PWAT JUST BELOW ONE
INCH...WILL QUICKLY MODIFY AS THE DAY PROGRESSES AND THE HIGH MOVES
OFFSHORE. PWAT ON THESE SAME FORECAST SOUNDINGS ARE SHOWN TO
INCREASE TO AROUND 1.5 INCHES BY 03Z TUE. EVEN WITH INCREASING
MOISTURE...WILL KEEP THE FORECAST DRY ON MONDAY DUE TO VERY LIMITED
SYNOP SCALE AND LOW LEVEL FORCING.
THE AFOREMENTIONED SHORT WAVE IS PROGGED TO CROSS THE MOUNTAINS
MONDAY NIGHT AND MOVE ACROSS MID ATLANTIC AND CAROLINAS ON TUESDAY.
THE COMBINATION OF INCREASING MOISTURE AND SYNOPTIC SCALE FORCING
WITH THE SHORT WAVE WILL BRING INCREASED RAIN CHANCES TO THE AREA
LATE MONDAY NIGHT ACROSS OUR WESTERN ZONES...AND TUESDAY ACROSS ALL
OF CENTRAL NC.
DURING THE MID-WEEK PERIOD...THE WESTERLIES WILL SHIFT NORTH WITH A
WEAK RIDGE BECOMING ESTABLISHED ACROSS OUR AREA. THIS PATTERN WILL
RESULT IN A MORE TYPICAL SUMMERTIME PATTERN WITH ISOLATED TO
SCATTERED AFTERNOON/EVENING SHOWERS AND TSTMS.
BY LATE WEEK...THE NEXT SHORT WAVE AND COLD FRONT WILL APPROACH FROM
THE NW...THUS LOOK FOR INCREASING RAIN CHANCES ESP LATE ON FRIDAY.
THIS SOLUTION IS SLIGHTLY LATER IN TIMING THAN EARLIER MODEL
RUNS...WHICH BROUGHT THIS SAME SYSTEM IN AS EARLY AS LATE THURSDAY.
TEMPS DURING THE LONG TERM: A FEW DEGREES BELOW NORMAL TO START OFF
THE WEEK (LOWS IN THE MID 60S AND HIGHS IN THE MID-UPPER 80S) AS LOW
LEVEL THICKNESSES DECREASE IN THE WAKE OF THE TROUGH PASSAGE. THEN
TEMPERATURES WILL REBOUND TO NORMAL (LOWS IN THE UPPER 60S TO NEAR
70 AND HIGHS IN THE UPPER 80S TO NEAR 90) DURING THE MID-LATE WEEK
PERIOD AS THE RIDGE BUILDS OVER THE REGION.
&&
.AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
AS OF 215 AM SATURDAY...
VFR CONDITIONS SHOULD PREVAIL DURING THE 06Z VALID TAF PERIOD. IN A
MORE MOIST AIR MASS...AND FOLLOWING AREAS OF HEAVY RAIN CLOSE BY...
A PERIOD OF IFR CONDITIONS ARE EXPECTED MAINLY TOWARD KFAY DURING
THE EARLY MORNING HOURS. AS A BRIEF PERIOD OF CLEARING OCCURS DURING
THE EARLY MORNING...VISIBILITIES COULD DROP TO AT LEAST MVFR TOWARD
KRDU AND KRWI. SCATTERED SHOWERS AND THUNDERSTORMS WOULD PRODUCE
SUB-VFR CONDITIONS BUT CURRENT POINT FORECAST PROBABILITY WAS
INSUFFICIENT TO INCLUDE IN A PREVAILING OR TEMPORARY MODE AT TAF
SITES.
BEYOND THE 06Z VALID TAF PERIOD...THERE IS A CHANCE OF EARLY MORNING
LOW CLOUDS MAINLY TOWARD KRWI AND KFAY SUNDAY BEFORE A COLD FRONT
MOVES THROUGH. THIS FRONT...MOVING THROUGH SUNDAY...WILL TURN WINDS
INCREASINGLY MORE TO THE NORTH AND BRING DRIER AIR INTO CENTRAL
NORTH CAROLINA. HIGH POTENTIAL OF VFR CONDITIONS UNDER HIGH PRESSURE
OVERNIGHT SUNDAY INTO MONDAY...THEN MOISTURE INCREASES ONCE AGAIN BY
TUESDAY...RENEWING CHANCES OF SHOWERS AND THUNDERSTORMS FOR THE
MIDDLE OF THE WEEK. CHANCES OF LATE NIGHT AND EARLY MORNING LOW
CLOUDS INCREASE AS WELL...WITH THE CURRENT GUIDANCE HIGHER WITH
THESE TOWARD THE TRIAD WEDNESDAY MORNING.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...DJF
NEAR TERM...DJF
SHORT TERM...DJF
LONG TERM...NP
AVIATION...DJF
AREA FORECAST DISCUSSION
NWS RALEIGH NC
255 AM EDT SAT AUG 3 2013
.SYNOPSIS...
AS A WEAK FRONT LIES OVER THE AREA...ANOTHER...STRONGER COLD FRONT
APPROACHES FROM THE NORTHWEST. THIS FRONT WILL PASS THROUGH THE
REGION SUNDAY. HIGH PRESSURE BUILDS IN BEHIND THE FRONT MONDAY
BEFORE MOVING OFF THE MID-ATLANTIC COAST TUESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 10 PM FRIDAY...
A WEAKENING SURFACE BOUNDARY LOCATED ACROSS SOUTH/SOUTHEASTERN
PORTIONS OF THE AREA COMBINED WITH STILL SUFFICIENT INSTABILITY LATE
THIS EVENING ARE SUPPORTING SHOWER AND THUNDERSTORM DEVELOPMENT
OVER PORTIONS OF THE SANDHILLS AND SOUTHERN COASTAL PLAIN. THE SPC
MESO PAGE IS STILL SHOWING UPWARDS OF 2000 J/KG OF MLCAPE... WITH A
SLOWLY STABILIZING BOUNDARY LAYER. THE LATEST HRRR AND OTHER HI-RES
MODELS SHOW THIS ACTIVITY GRADUALLY WEAKENING THIS LATE THIS INTO
THE EARLY MORNING HOURS OF SATURDAY. THIS SEEMS REASONABLE.
HOWEVER... A WEAK IMPULSE OR TWO MOVING THROUGH THE WEST TO
WEST-NORTHWEST MID LEVEL FLOW COULD HELP A FEW ISOLATED SHOWERS
DEVELOP EVEN AFTER 06Z INVOF THE WEAK FRONT. WILL SHOW A GOOD CHANCE
FOR SHOWERS AND STORMS THROUGH 06Z ACROSS THE AREA MENTION ABOVE
(SE)... TRANSITING TO A SLIGHT CHANCE OF STORMS AFTER 06Z (WILL ADD
TO NEXT UPDATE TO FORECAST AROUND 1130-12)... WITH A DRY FORECAST
ELSEWHERE. DO NOT EXPECT ANY SVR WEATHER FROM THESE SHOWERS AND
STORMS... BUT LOCALIZED FLOODING MAY BE POSSIBLE... ESPECIALLY
ACROSS PORTIONS OF CUMBERLAND AND NORTHERN SAMPSON COUNTIES (WHERE
MODERATE TO HEAVY RAIN HAS BEEN FALLING FOR SEVERAL HOURS). EXPECT
SKIES WILL AT LEAST BE PARTLY TO MOSTLY CLOUDY OVERNIGHT... WITH AT
LEAST SOME MID/HIGH LEVEL DEBRIS CLOUDINESS FROM CONVECTION
UPSTREAM. IN ADDITION... THINK WE CLOUD SEE SOME LOW STRATUS AND OR
FOG... ESPECIALLY INVOF THE WEAK BOUNDARY. GIVEN THIS HAVE BUMPED UP
LOW TEMPS BY A COUPLE OF DEGREES INTO THE UPPER 60S NW TO LOWER 70S
SE.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 245 PM FRIDAY...
SATURDAY...
THE WEAK FRONTAL ZONE OVER SOUTHERN AND EASTERN NC WILL WASH OUT BY
SATURDAY AND SOUTHERLY SURFACE FLOW WILL PREVAIL ACROSS A GOOD
PORTION OF CENTRAL NC. THIS WILL ALLOW 70 DEGREE DEWPOINTS AND
BETTER INSTABILITY TO CREEP BACK TO THE NORTH...ALTHOUGH
NORTHWESTERLY FLOW AND STRONGER MIXING SHOULD SUPPRESS INSTABILITY
SOMEWHAT OVER THE NORTHWEST AND NORTHERN PIEDMONT. MODELS SHOW A
THERMALLY ENHANCE LEE TROUGH DURING THE AFTERNOON...THOUGH WITH ONLY
WEAK MASS CONVERGENCE AND SUBTLE RIPPLES IN THE PREVAILING NORTHWEST
FLOW ALOFT. THUS...SHOWERS AND STORMS YOU BE MOSTLY ISOLATED
OUTSIDE OF THE SEABREEZE OR STORMS MOVING OFF THE HIGHER TERRAIN.
SATURDAY NIGHT...
A STRONG SHORTWAVE MOVING THROUGH THE LONGWAVE TROUGH WILL PUSH A
MODEST COLD FRONT TOWARD OUR AREA LATE SATURDAY AND SUNDAY.
HOWEVER...WESTERLY DEEP LAYER FLOW AHEAD OF THE FRONT SHOULD
LIMIT MOISTURE AVAILABILITY...AND UNLESS MORE ORGANIZED CONVECTION
OVER THE MID-ATLANTIC STATES SENDS OUTFLOW SOUTH THROUGH VA...MOST
OF SATURDAY NIGHT APPEARS TO BE DRY. WILL INDICATE BETTER CLOUD
COVER ACROSS THE NORTH...WITH LOWS IN THE UPPER 60S AND LOWER 70S.
-BLS
SUNDAY AND SUNDAY NIGHT...
STRONG SHORTWAVE TROUGH OVER ONTARIO WILL DIVE SOUTHEAST THROUGH THE
EASTERN GREAT LAKES AND AND SOUTHERN NEW ENGLAND STATES ON
SUNDAY...REINFORCING THE EASTERN US TROUGH AND PAVING THE WAY FOR
YET ANOTHER WELL DEFINED SYNOPTIC SURFACE COLD FRONT INTO PARTS OF
THE SOUTHEAST STATES SUNDAY-SUNDAY NIGHT. OVER THE PAST 24
HOURS...NWP MODELS HAVE REALLY HONED IN WITH THE TIMING OF THE FRONT
THROUGH THE AREA BETWEEN 12 TO 18Z SUNDAY. MODELS HAVE ALSO TRENDED
DRIER WITH THE PASSAGE OF THE FRONT THROUGH THE CAROLINAS...OWING TO
THE EARLIER/UNFAVORABLE DIURNAL TIMING...WEAKENING-NEARLY NEGLIGIBLE
S/W DYNAMICS AT MORE SOUTHERN LATITUDES AS CORE OF DPVA AND H5 FALLS
SLIDE OFF THE NORTHERN MID-ATLANTIC SEABOARD...AND LASTLY THE LACK
OF DEEP MOISTURE TRANSPORT INTO THE AREA...ROBBED/DISRUPTED BY THE
SUBDUING EFFECTS OF THE DEEP WEST-NORTHWESTERLY FLOW IN PLACE EAST
OF THE MOUNTAINS.
AS SUCH...EXPECT TO SEE DIMINISHING RADAR TRENDS ACROSS CENTRAL NC
WITH LITTLE MORE THAN ISOLATED TO WIDELY SCATTERED SHOWERS
POSSIBLE...WITH BEST CHANCE ACROSS THE SOUTH DURING THE AFTERNOON
BEFORE THE FRONT SETTLES SOUTH OF THE AREA SUNDAY EVENING. IN THE
CASE THAT SOME MORE ORGANIZED CONVECTION DEVELOPS...MODERATELY
STRONG WESTERLIES IN THE MID LEVELS OF 40 TO 45KTS COULD SUPPORT AN
ISOLATED STRONG TO SEVERE STORM.
HIGHS IN THE MID 80S NORTH TO AROUND 90 SOUTH. THE NORTH-SOUTH
LOW-LEVEL COOL DRY AIR ADVECTION SUNDAY NIGHT SHOULD RESULT IN A
LARGER TEMPERATURE SPREAD THAN NORMAL FOR THIS TIME OF YEAR. LOWS IN
THE LOWER 60S NORTH(NEAR 60 ROXBORO)TO MID/UPPER 60S SOUTH. -CBL
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
AS OF 255 AM SATURDAY...
HIGH PRESSURE WILL MOVE ACROSS THE MID ATLANTIC REGION ON MONDAY...
MOVING OFFSHORE BY 00Z TUE AS A MID LEVEL SHORT WAVE EMBEDDED IN THE
NW FLOW MOVES SE ACROSS THE MIDWEST. A DRY AIRMASS OVER THE STATE
EARLY MONDAY...PER FORECAST SOUNDINGS WHICH SHOW PWAT JUST BELOW ONE
INCH...WILL QUICKLY MODIFY AS THE DAY PROGRESSES AND THE HIGH MOVES
OFFSHORE. PWAT ON THESE SAME FORECAST SOUNDINGS ARE SHOWN TO
INCREASE TO AROUND 1.5 INCHES BY 03Z TUE. EVEN WITH INCREASING
MOISTURE...WILL KEEP THE FORECAST DRY ON MONDAY DUE TO VERY LIMITED
SYNOP SCALE AND LOW LEVEL FORCING.
THE AFOREMENTIONED SHORT WAVE IS PROGGED TO CROSS THE MOUNTAINS
MONDAY NIGHT AND MOVE ACROSS MID ATLANTIC AND CAROLINAS ON TUESDAY.
THE COMBINATION OF INCREASING MOISTURE AND SYNOPTIC SCALE FORCING
WITH THE SHORT WAVE WILL BRING INCREASED RAIN CHANCES TO THE AREA
LATE MONDAY NIGHT ACROSS OUR WESTERN ZONES...AND TUESDAY ACROSS ALL
OF CENTRAL NC.
DURING THE MID-WEEK PERIOD...THE WESTERLIES WILL SHIFT NORTH WITH A
WEAK RIDGE BECOMING ESTABLISHED ACROSS OUR AREA. THIS PATTERN WILL
RESULT IN A MORE TYPICAL SUMMERTIME PATTERN WITH ISOLATED TO
SCATTERED AFTERNOON/EVENING SHOWERS AND TSTMS.
BY LATE WEEK...THE NEXT SHORT WAVE AND COLD FRONT WILL APPROACH FROM
THE NW...THUS LOOK FOR INCREASING RAIN CHANCES ESP LATE ON FRIDAY.
THIS SOLUTION IS SLIGHTLY LATER IN TIMING THAN EARLIER MODEL
RUNS...WHICH BROUGHT THIS SAME SYSTEM IN AS EARLY AS LATE THURSDAY.
TEMPS DURING THE LONG TERM: A FEW DEGREES BELOW NORMAL TO START OFF
THE WEEK (LOWS IN THE MID 60S AND HIGHS IN THE MID-UPPER 80S) AS LOW
LEVEL THICKNESSES DECREASE IN THE WAKE OF THE TROUGH PASSAGE. THEN
TEMPERATURES WILL REBOUND TO NORMAL (LOWS IN THE UPPER 60S TO NEAR
70 AND HIGHS IN THE UPPER 80S TO NEAR 90) DURING THE MID-LATE WEEK
PERIOD AS THE RIDGE BUILDS OVER THE REGION.
&&
.AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
AS OF 215 AM SATURDAY...
VFR CONDITIONS SHOULD PREVAIL DURING THE 06Z VALID TAF PERIOD. IN A
MORE MOIST AIR MASS...AND FOLLOWING AREAS OF HEAVY RAIN CLOSE BY...
A PERIOD OF IFR CONDITIONS ARE EXPECTED MAINLY TOWARD KFAY DURING
THE EARLY MORNING HOURS. AS A BRIEF PERIOD OF CLEARING OCCURS DURING
THE EARLY MORNING...VISIBILITIES COULD DROP TO AT LEAST MVFR TOWARD
KRDU AND KRWI. SCATTERED SHOWERS AND THUNDERSTORMS WOULD PRODUCE
SUB-VFR CONDITIONS BUT CURRENT POINT FORECAST PROBABILITY WAS
INSUFFICIENT TO INCLUDE IN A PREVAILING OR TEMPORARY MODE AT TAF
SITES.
BEYOND THE 06Z VALID TAF PERIOD...THERE IS A CHANCE OF EARLY MORNING
LOW CLOUDS MAINLY TOWARD KRWI AND KFAY SUNDAY BEFORE A COLD FRONT
MOVES THROUGH. THIS FRONT...MOVING THROUGH SUNDAY...WILL TURN WINDS
INCREASINGLY MORE TO THE NORTH AND BRING DRIER AIR INTO CENTRAL
NORTH CAROLINA. HIGH POTENTIAL OF VFR CONDITIONS UNDER HIGH PRESSURE
OVERNIGHT SUNDAY INTO MONDAY...THEN MOISTURE INCREASES ONCE AGAIN BY
TUESDAY...RENEWING CHANCES OF SHOWERS AND THUNDERSTORMS FOR THE
MIDDLE OF THE WEEK. CHANCES OF LATE NIGHT AND EARLY MORNING LOW
CLOUDS INCREASE AS WELL...WITH THE CURRENT GUIDANCE HIGHER WITH
THESE TOWARD THE TRIAD WEDNESDAY MORNING.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...DJF
NEAR TERM...BSD
SHORT TERM...BLS/CBL
LONG TERM...NP
AVIATION...DJF
AREA FORECAST DISCUSSION
NWS RALEIGH NC
215 AM EDT SAT AUG 3 2013
.SYNOPSIS...
AS A WEAK FRONT LIES OVER THE AREA...ANOTHER...STRONGER COLD FRONT
APPROACHES FROM THE NORTHWEST. THIS FRONT WILL PASS THROUGH THE
REGION SUNDAY. HIGH PRESSURE BUILDS IN BEHIND THE FRONT MONDAY
BEFORE MOVING OFF THE MID-ATLANTIC COAST TUESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 10 PM FRIDAY...
A WEAKENING SURFACE BOUNDARY LOCATED ACROSS SOUTH/SOUTHEASTERN
PORTIONS OF THE AREA COMBINED WITH STILL SUFFICIENT INSTABILITY LATE
THIS EVENING ARE SUPPORTING SHOWER AND THUNDERSTORM DEVELOPMENT
OVER PORTIONS OF THE SANDHILLS AND SOUTHERN COASTAL PLAIN. THE SPC
MESO PAGE IS STILL SHOWING UPWARDS OF 2000 J/KG OF MLCAPE... WITH A
SLOWLY STABILIZING BOUNDARY LAYER. THE LATEST HRRR AND OTHER HI-RES
MODELS SHOW THIS ACTIVITY GRADUALLY WEAKENING THIS LATE THIS INTO
THE EARLY MORNING HOURS OF SATURDAY. THIS SEEMS REASONABLE.
HOWEVER... A WEAK IMPULSE OR TWO MOVING THROUGH THE WEST TO
WEST-NORTHWEST MID LEVEL FLOW COULD HELP A FEW ISOLATED SHOWERS
DEVELOP EVEN AFTER 06Z INVOF THE WEAK FRONT. WILL SHOW A GOOD CHANCE
FOR SHOWERS AND STORMS THROUGH 06Z ACROSS THE AREA MENTION ABOVE
(SE)... TRANSITING TO A SLIGHT CHANCE OF STORMS AFTER 06Z (WILL ADD
TO NEXT UPDATE TO FORECAST AROUND 1130-12)... WITH A DRY FORECAST
ELSEWHERE. DO NOT EXPECT ANY SVR WEATHER FROM THESE SHOWERS AND
STORMS... BUT LOCALIZED FLOODING MAY BE POSSIBLE... ESPECIALLY
ACROSS PORTIONS OF CUMBERLAND AND NORTHERN SAMPSON COUNTIES (WHERE
MODERATE TO HEAVY RAIN HAS BEEN FALLING FOR SEVERAL HOURS). EXPECT
SKIES WILL AT LEAST BE PARTLY TO MOSTLY CLOUDY OVERNIGHT... WITH AT
LEAST SOME MID/HIGH LEVEL DEBRIS CLOUDINESS FROM CONVECTION
UPSTREAM. IN ADDITION... THINK WE CLOUD SEE SOME LOW STRATUS AND OR
FOG... ESPECIALLY INVOF THE WEAK BOUNDARY. GIVEN THIS HAVE BUMPED UP
LOW TEMPS BY A COUPLE OF DEGREES INTO THE UPPER 60S NW TO LOWER 70S
SE.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 245 PM FRIDAY...
SATURDAY...
THE WEAK FRONTAL ZONE OVER SOUTHERN AND EASTERN NC WILL WASH OUT BY
SATURDAY AND SOUTHERLY SURFACE FLOW WILL PREVAIL ACROSS A GOOD
PORTION OF CENTRAL NC. THIS WILL ALLOW 70 DEGREE DEWPOINTS AND
BETTER INSTABILITY TO CREEP BACK TO THE NORTH...ALTHOUGH
NORTHWESTERLY FLOW AND STRONGER MIXING SHOULD SUPPRESS INSTABILITY
SOMEWHAT OVER THE NORTHWEST AND NORTHERN PIEDMONT. MODELS SHOW A
THERMALLY ENHANCE LEE TROUGH DURING THE AFTERNOON...THOUGH WITH ONLY
WEAK MASS CONVERGENCE AND SUBTLE RIPPLES IN THE PREVAILING NORTHWEST
FLOW ALOFT. THUS...SHOWERS AND STORMS YOU BE MOSTLY ISOLATED
OUTSIDE OF THE SEABREEZE OR STORMS MOVING OFF THE HIGHER TERRAIN.
SATURDAY NIGHT...
A STRONG SHORTWAVE MOVING THROUGH THE LONGWAVE TROUGH WILL PUSH A
MODEST COLD FRONT TOWARD OUR AREA LATE SATURDAY AND SUNDAY.
HOWEVER...WESTERLY DEEP LAYER FLOW AHEAD OF THE FRONT SHOULD
LIMIT MOISTURE AVAILABILITY...AND UNLESS MORE ORGANIZED CONVECTION
OVER THE MID-ATLANTIC STATES SENDS OUTFLOW SOUTH THROUGH VA...MOST
OF SATURDAY NIGHT APPEARS TO BE DRY. WILL INDICATE BETTER CLOUD
COVER ACROSS THE NORTH...WITH LOWS IN THE UPPER 60S AND LOWER 70S.
-BLS
SUNDAY AND SUNDAY NIGHT...
STRONG SHORTWAVE TROUGH OVER ONTARIO WILL DIVE SOUTHEAST THROUGH THE
EASTERN GREAT LAKES AND AND SOUTHERN NEW ENGLAND STATES ON
SUNDAY...REINFORCING THE EASTERN US TROUGH AND PAVING THE WAY FOR
YET ANOTHER WELL DEFINED SYNOPTIC SURFACE COLD FRONT INTO PARTS OF
THE SOUTHEAST STATES SUNDAY-SUNDAY NIGHT. OVER THE PAST 24
HOURS...NWP MODELS HAVE REALLY HONED IN WITH THE TIMING OF THE FRONT
THROUGH THE AREA BETWEEN 12 TO 18Z SUNDAY. MODELS HAVE ALSO TRENDED
DRIER WITH THE PASSAGE OF THE FRONT THROUGH THE CAROLINAS...OWING TO
THE EARLIER/UNFAVORABLE DIURNAL TIMING...WEAKENING-NEARLY NEGLIGIBLE
S/W DYNAMICS AT MORE SOUTHERN LATITUDES AS CORE OF DPVA AND H5 FALLS
SLIDE OFF THE NORTHERN MID-ATLANTIC SEABOARD...AND LASTLY THE LACK
OF DEEP MOISTURE TRANSPORT INTO THE AREA...ROBBED/DISRUPTED BY THE
SUBDUING EFFECTS OF THE DEEP WEST-NORTHWESTERLY FLOW IN PLACE EAST
OF THE MOUNTAINS.
AS SUCH...EXPECT TO SEE DIMINISHING RADAR TRENDS ACROSS CENTRAL NC
WITH LITTLE MORE THAN ISOLATED TO WIDELY SCATTERED SHOWERS
POSSIBLE...WITH BEST CHANCE ACROSS THE SOUTH DURING THE AFTERNOON
BEFORE THE FRONT SETTLES SOUTH OF THE AREA SUNDAY EVENING. IN THE
CASE THAT SOME MORE ORGANIZED CONVECTION DEVELOPS...MODERATELY
STRONG WESTERLIES IN THE MID LEVELS OF 40 TO 45KTS COULD SUPPORT AN
ISOLATED STRONG TO SEVERE STORM.
HIGHS IN THE MID 80S NORTH TO AROUND 90 SOUTH. THE NORTH-SOUTH
LOW-LEVEL COOL DRY AIR ADVECTION SUNDAY NIGHT SHOULD RESULT IN A
LARGER TEMPERATURE SPREAD THAN NORMAL FOR THIS TIME OF YEAR. LOWS IN
THE LOWER 60S NORTH(NEAR 60 ROXBORO)TO MID/UPPER 60S SOUTH. -CBL
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
AS OF 315 PM FRIDAY...
LOW-LEVEL DRY AIR FEED INTO THE AREA TO START THE WORK WEEK AS HIGH
PRESSURE BUILDS ACROSS THE OHIO VALLEY. CONVECTION IS EXPECTED TO BE
LARGELY SUPPRESSED TO OUR SOUTH ON MONDAY...AS S/W DISTURBANCES IN
THE NW FLOW ALOFT RUNNING ATOP THE LOW-LEVEL FRONTAL ZONE SOUTH OF
THE AREA COULD SUPPORT AN ORGANIZED SEVERE THREAT ACROSS THE DEEP
SOUTH. ONCE THE HIGH SHIFTS OFFSHORE ON TUESDAY...RETURN FLOW WILL
BRING A RETURN TO THE TYPICAL SUMMERTIME PATTERN FOR THE MID-WEEK
PERIOD...WITH ISOLATED TO SCATTERED AFTERNOON/EVENING SHOWERS AND
TSTMS.
RAIN CHANCES WILL INCREASE TOWARD LATE IN THE WORK WEEK AS AN
EASTWARD MOVING AREA OF LOW PRESSURE THROUGH GREAT LAKES AND
ATTENDANT TRAILING SURFACE FRONT APPROACH THE AREA ON THURSDAY
BEFORE POSSIBLY STALLING ACROSS THE REGION ON FRIDAY.
ADDITIONALLY...AS IS ALWAYS THE CASE WITH NW FLOW ALOFT DURING THE
SUMMER...CONVECTIVE CHANCES COULD BE AUGMENTED FURTHER BY THE TIMING
OF UPSTREAM CONVECTIVELY INDUCED/HYBRID VORTICITY CENTERS INTO THE
AREA. SEASONABLE TEMPERATURES ALL OF NEXT WEEK. HIGHS IN THE MID TO
UPPER 80S. LOWS IN THE MID 60 TO LOWER 70S.
&&
.AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
AS OF 215 AM SATURDAY...
VFR CONDITIONS SHOULD PREVAIL DURING THE 06Z VALID TAF PERIOD. IN A
MORE MOIST AIR MASS...AND FOLLOWING AREAS OF HEAVY RAIN CLOSE BY...
A PERIOD OF IFR CONDITIONS ARE EXPECTED MAINLY TOWARD KFAY DURING
THE EARLY MORNING HOURS. AS A BRIEF PERIOD OF CLEARING OCCURS DURING
THE EARLY MORNING...VISIBILITIES COULD DROP TO AT LEAST MVFR TOWARD
KRDU AND KRWI. SCATTERED SHOWERS AND THUNDERSTORMS WOULD PRODUCE
SUB-VFR CONDITIONS BUT CURRENT POINT FORECAST PROBABILITY WAS
INSUFFICIENT TO INCLUDE IN A PREVAILING OR TEMPORARY MODE AT TAF
SITES.
BEYOND THE 06Z VALID TAF PERIOD...THERE IS A CHANCE OF EARLY MORNING
LOW CLOUDS MAINLY TOWARD KRWI AND KFAY SUNDAY BEFORE A COLD FRONT
MOVES THROUGH. THIS FRONT...MOVING THROUGH SUNDAY...WILL TURN WINDS
INCREASINGLY MORE TO THE NORTH AND BRING DRIER AIR INTO CENTRAL
NORTH CAROLINA. HIGH POTENTIAL OF VFR CONDITIONS UNDER HIGH PRESSURE
OVERNIGHT SUNDAY INTO MONDAY...THEN MOISTURE INCREASES ONCE AGAIN BY
TUESDAY...RENEWING CHANCES OF SHOWERS AND THUNDERSTORMS FOR THE
MIDDLE OF THE WEEK. CHANCES OF LATE NIGHT AND EARLY MORNING LOW
CLOUDS INCREASE AS WELL...WITH THE CURRENT GUIDANCE HIGHER WITH
THESE TOWARD THE TRIAD WEDNESDAY MORNING.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...DJF
NEAR TERM...BSD
SHORT TERM...BLS/CBL
LONG TERM...CBL
AVIATION...DJF
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
600 AM EDT SAT AUG 3 2013
.SYNOPSIS...
AN UNSEASONABLY AMPLIFIED AND PERSISTENT EARLY AUGUST WEATHER
PATTERN WILL BE HIGHLIGHTED BY HIGHER LATITUDE BLOCKING OVER
NORTHERN CANADA AND MEAN TROUGHING OVER EASTERN NORTH AMERICA.
THIS WILL RESULT IN A PERIOD OF RELATIVELY COOL TEMPERATURES
THROUGH EARLY NEXT WEEK. SHOWERS WILL ACCOMPANY A COLD FRONT
MOVING THROUGH THE AREA TODAY...FOLLOWED BY DRY WEATHER FOR
SUNDAY INTO EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
A SHORTWAVE TROUGH IS FCST TO DIG SEWD ACROSS THE GREAT LAKES
REGION INTO THE NORTHEAST THROUGH TONIGHT...SENDING ITS ASSOCD
COLD FRONT INTO THE SRN MID-ATLANTIC STATES BY 12Z SUNDAY. THE
COLD FRONT WILL SERVE AS A FOCUS FOR SHOWERS AND PERHAPS A FEW
ISOLD TSTMS AS IT PUSHES SEWD THRU CNTRL PA TODAY. STG WSWLY H85
LLJ WILL FEED MSTR EWD FM THE OH VLY INTO THE BOUNDARY...WITH THE
BEST MSTR FLUX OCCURRING EARLY THIS MORNING. MODEL QPFS FOR THE
MOST PART ARE IN REASONABLE AGREEMENT WITH LGT AMTS GENERALLY AOB
0.25 INCH. OVERALL...THE BEST CHC FOR RAIN TODAY WILL BE OVER
AREAS ALONG AND TO THE SOUTH OF I-80...WITH SHOWERS BCMG LESS
NMRS/MORE SCT INTO THE AFTN HOURS.
SPC HAS PLACED A SEE TEXT LABEL NEAR THE PA/MD LINE...INDICATING A
LOW/LIMITED THREAT FOR SVR STORMS...WHICH IS DUE TO AN OVERALL
LACK OF BUOYANCY. HOWEVER..ANY CLOUD BREAKS/INSOLATION OF 60F
DEWPOINT AIRMASS COULD LEAD TO POCKETS OF GREATER INSTABILITY WITH
QUASI-LINER STORM MOTIONS TAPPING STG WINDS ALOFT AND UNIDIRECTIONAL
DEEP-LAYER FLOW - ORIENTED PARALLEL TO THE FRONTAL BOUNDARY. WILL
SEE HOW FAR NORTH THEY DRAW THE 5PCT DMGG WIND PROB WITH THE 13Z
UPDATE FOR HWO PURPOSES.
THE FRONT MAY BRIEFLY STALL-OUT OR BECOME Q-STNRY INVOF THE MASON
DIXON LINE EARLY TONIGHT...AS A WAVE SLIDES EWD ALONG THE
BOUNDARY. THIS MAY PROLONG SHOWERS ACRS THE SRN TIER ZONES AND
THEREFORE KEPT THE HIGHEST POPS ALONG/SOUTH OF THE TURNPIKE. DRIER
AIR WILL BE OVERSPREADING THE AREA FROM NORTH TO SOUTH WITH PWS
DROPPING BELOW NORMAL ACRS THE ENTIRE AREA BY 12Z SUNDAY.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
SFC HIGH PRESSURE WILL MOVE FROM WI INTO WRN PA BY 12Z MON BEFORE
SLIDING OFF THE MID-ATLC COAST BY TUES MORNG. COOL AND DRY
CONDITIONS WILL PREVAIL THRU MUCH OF THE PERIOD...WITH JUST A SCHC
OF AN ISOLD SHOWER SUN AFTN AS PLUME OF RELATIVELY STEEP MID-LVL
LAPSE RATES ROTATES THRU N-CNTRL AND NERN PA. TEMPS WILL AVG BELOW
NORMAL. SUN NGT/MON MORNG LOOKS RATHER CHILLY WITH SOME AREAS IN
THE NRN MTNS POSSIBLY DROPPING INTO THE UPPER 30S. AS THE HIGH
SLIDES TO THE EAST...WAA PATTERN WILL EVOLVE EWD FROM THE OH VLY
WITH GFS/EC SUGGESTING SHOWERS PSBL IN SWRN/SCNTRL PA BY 12Z TUE.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
SLY LLVL FLOW SHOULD BRING GRADUALLY WARMER/MORE HUMID AIR BACK
INTO CNTRL PA ON TUES...WITH SOME ISOLD/SCT AFTN CONVECTION PSBL.
RETROGRADING VORTEX OVER HUDSON BAY/SRN CANADA SHOULD ALLOW THE
FLOW ALOFT TO SHIFT MORE TO THE SW INTO THE MIDDLE TO LATER PART
OF NEXT WEEK. 00Z MDL AND ENSEMBLE DATA SHOW A COLD FRONT
PROGRESSING EWD FM THE NRN PLAINS/UPPER GRT LKS TWD THE NORTHEAST
AND MID-ATLC STATES DURING THE SECOND HALF OF NEXT WEEK. THIS
FRONT WILL BE ACCOMPANIED BY RNFL OF VARYING INTENSITY AS IT
CROSSES THE REGION SOMETIME WED-THR. THE FRONT MAY STALL OR SLOW
DOWN AS IT NEARS THE COAST...WHICH WOULD KEEP SHOWERS IN THE FCST
OVR SERN PA INTO FRIDAY BEFORE THINGS CLR OUT BY THE WEEKEND.
&&
.AVIATION /10Z SATURDAY THROUGH WEDNESDAY/...
ALTHOUGH RADAR SHOWS A WIDESPREAD AREA OF RAIN SHOWERS CROSSING
THE REGION...LITTLE ACTIVITY REACHING THE SURFACE EXCEPT IN SOME
ISOLATED HEAVIER SHOWERS NEAR KERI.
CURRENT OBSERVATIONS ALONG WITH RAP SHORT TERM FORECASTS INDICATE
CEILINGS SHOULD REMAIN VFR TO MVFR THROUGH THE FORECAST PERIOD.
THE LATEST CALL TO THE KBFD ASOS INDICATED 1100 FT OVC. IF ANY
AIRFIELD WILL FLIRT WITH DROPPING BELOW VFR CEILINGS...THIS WOULD
BE IT.
KEPT ALL SITES IN LINE WITH CURRENT CONDITIONS WITH THE ADDITION OF
VCSH BASED ON RADAR COVERAGE.
ANY SHOWERS THAT DO REACH THE GROUND WILL BE SLIDING SOUTH THROUGH
THE MID MORNING HOURS. WITH ONLY A MARGINAL SLIVER OF CAPE
ACCOMPANYING THE PRECIP...DO NOT EXPECT CONVECTION TO DEVELOP. BY
MID AFTERNOON...PRECIP SHOULD EXIT THE AREA.
OUTLOOK...
SUN-WED...VFR. NO SIG WX. AM FOG POSSIBLE. PERHAPS
A SHOWER LATE WED.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...STEINBUGL
NEAR TERM...STEINBUGL
SHORT TERM...STEINBUGL
LONG TERM...STEINBUGL
AVIATION...TYBURSKI
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
327 AM EDT SAT AUG 3 2013
.SYNOPSIS...
AN UNSEASONABLY AMPLIFIED AND PERSISTENT LARGE SCALE WEATHER
PATTERN WILL BE HIGHLIGHTED BY HIGHER LATITUDE BLOCKING OVER
NORTHERN CANADA AND MEAN TROUGHING OVER EASTERN NORTH AMERICA.
THIS WILL RESULT IN A PERIOD OF RELATIVELY COOL TEMPERATURES
THROUGH EARLY NEXT WEEK. SHOWERS WILL ACCOMPANY A COLD FRONT
MOVING THROUGH THE AREA TODAY...FOLLOWED BY DRY WEATHER FOR
SUNDAY INTO EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
A SHORTWAVE TROUGH IS FCST TO DIG SEWD ACROSS THE GREAT LAKES
REGION INTO THE NORTHEAST THIS PERIOD...SENDING ITS ASSOCD COLD
FRONT /TRAILING FROM THE ST. LAWRENCE VALLEY SWWD THRU THE LOWER
GREAT LKS/ INTO THE MID-ATLANTIC STATES BY 12Z SUNDAY. THE COLD
FRONT WILL SERVE AS A FOCUS FOR SHOWERS AND PERHAPS A FEW ISOLD
TSTMS AS IT PUSHES SEWD THRU CNTRL PA TODAY. STG WSWLY H85 LLJ
WILL FEED MSTR EWD FM THE OH VLY INTO THE BOUNDARY...WITH THE
BEST MSTR FLUX OCCURRING EARLY THIS MORNING. MODEL QPFS FOR THE
MOST PART ARE IN REASONABLE AGREEMENT WITH AMTS GENERALLY AOB
0.25 INCH. OVERALL...THE BEST CHC FOR RAIN TODAY WILL BE OVER
AREAS ALONG AND TO THE SOUTH OF I-80.
SPC HAS PLACED A SEE TEXT LABEL NEAR THE PA/MD LINE...INDICATING A
LOW/LIMITED THREAT FOR SVR STORMS...WHICH IS DUE TO AN OVERALL
LACK OF BUOYANCY. HOWEVER..ANY CLOUD BREAKS/INSOLATION OF 60F
DEWPOINT AIRMASS COULD LEAD TO POCKETS OF GREATER INSTABILITY WITH
QUASI-LINER STORM MOTIONS TAPPING STG WINDS ALOFT AND UNIDIRECTIONAL
DEEP-LAYER FLOW - ORIENTED PARALLEL TO THE FRONTAL BOUNDARY.
THE FRONT MAY BRIEFLY STALL-OUT OR BECOME Q-STNRY INVOF THE MASON
DIXON LINE EARLY TONIGHT...AS A WAVE SLIDES EWD ALONG THE BOUNDARY.
THIS MAY PROLONG SHOWERS ACRS THE SRN TIER ZONES AND THEREFORE
KEPT THE HIGHEST POPS ALONG/SOUTH OF THE TURNPIKE. DRIER AIR WILL
BE OVERSPREADING THE AREA FROM NORTH TO SOUTH WITH PWS DROPPING
BELOW NORMAL ACRS THE ENTIRE AREA BY 12Z SUNDAY.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
SFC HIGH PRESSURE WILL MOVE FROM WI INTO WRN PA BY 12Z MON BEFORE
SLIDING OFF THE MID-ATLC COAST BY MON NGT. COOL AND DRY CONDITIONS
WILL PREVAIL THRU MUCH OF THE PERIOD...WITH JUST A SCHC OF AN ISOLD
SHOWER SUN AFTN AS PLUME OF RELATIVELY STEEP MID-LVL LAPSE RATES
ROTATES THRU N-CNTRL AND NERN PA. SUNDAY NIGHT-MONDAY MORNING
LOOKS RATHER CHILLY BY EARLY AUGUST STANDARDS...WITH WIDESPREAD
READINGS IN THE 45-55F RANGE. SOME OF THE USUALLY COLDER AREAS IN
THE NRN MTNS COULD DROP INTO THE UPPER 30S.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
CONSENSUS AMONG MED RANGE GUIDANCE FOR ANOTHER STRETCH OF
COOL/DRY WX INTO EARLY NEXT WEEK...AS COLD FRONT PRESSES SOUTH OF
PA AND COOL...CANADIAN HIGH PRES BUILDS SE ACROSS THE AREA. 00Z
GEFS 8H TEMPS REMAIN BLW NORMAL MON WHEN DAYTIME MAXES WILL
LIKELY BE 5-10F BLW NORMAL. NEGATIVE PWAT AND 8H TEMPS ANOMALIES
IN THE ENSEMBLE OUTPUT POINT TOWARD AN IDEAL SETUP FOR RADIATIONAL
COOLING MONDAY AND TUESDAY NIGHTS...AS SFC HIGH DRIFTS OVR THE
AREA. FOR MANY PARTS OF CENTRAL PA THESE COULD BE THE COOLEST
NIGHTS OF THE SUMMER SEASON. NORTHERN MTNS WILL BE SOLIDLY IN THE
40S...WITH LOWER TO MID 50S ELSEWHERE.
AXIS OF UPPER TROUGH SHIFTS FROM THE NORTHEAST CONUS TO THE
MIDWEST BY THE MID/LATE NEXT WEEK...INDICATING SLIGHTLY
WARMER...MORE HUMID AIR WILL MAKE A RETURN. CAN/T RULE OUT AN
ISOLD SHRA/TSRA CREEPING INTO THE SC MTNS AS EARLY AS TUE AFTN -
AS HINTED BY BOTH THE EC/GFS. HOWEVER...THE NEXT CHANCE FOR
WIDESPREAD PRECIPITATION WILL LIKELY NOT COME UNTIL LATE WED WITH
ARRIVAL OF A WARM FRONT OR AN EVEN BETTER CHANCE THURSDAY AS NEXT
COLD FRONT SLOWS AS IT PUSHES THROUGH.
&&
.AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
ALTHOUGH RADAR SHOWS A WIDESPREAD AREA OF RAIN SHOWERS CROSSING
THE REGION...LITTLE ACTIVITY REACHING THE SURFACE EXCEPT IN SOME
ISOLATED HEAVIER SHOWERS NEAR KERI.
CURRENT OBSERVATIONS ALONG WITH RAP SHORT TERM FORECASTS INDICATE
CEILINGS SHOULD REMAIN VFR TO MVFR THROUGH THE FORECAST PERIOD.
THE LATEST CALL TO THE KBFD ASOS INDICATED 1100 FT OVC. IF ANY
AIRFIELD WILL FLIRT WITH DROPPING BELOW VFR CEILINGS...THIS WOULD
BE IT.
KEPT ALL SITES IN LINE WITH CURRENT CONDITIONS WITH THE ADDITION OF
VCSH BASED ON RADAR COVERAGE.
ANY SHOWERS THAT DO REACH THE GROUND WILL BE SLIDING SOUTH THROUGH
THE MID MORNING HOURS. WITH ONLY A MARGINAL SLIVER OF CAPE
ACCOMPANYING THE PRECIP...DO NOT EXPECT CONVECTION TO DEVELOP. BY
MID AFTERNOON...PRECIP SHOULD EXIT THE AREA.
OUTLOOK...
SUN-WED...VFR. NO SIG WX. AM FOG POSSIBLE. PERHAPS
A SHOWER LATE WED.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...STEINBUGL
NEAR TERM...STEINBUGL
SHORT TERM...STEINBUGL
LONG TERM...RXR
AVIATION...MARTIN/TYBURSKI
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
144 AM EDT SAT AUG 3 2013
.SYNOPSIS...
A DEVELOPING LARGE HIGH LATITUDE BLOCK OVER NORTHERN CANADA WILL
FORCE SHORT-WAVE ENERGY INTO EASTERN NORTH AMERICA FOR MOST OF
THE NEXT 7 DAYS OR MORE. THE RESULT WILL BE A PERIOD OF RELATIVELY
COOL DRY WEATHER WITH A MID-TROPOSPHERIC TROUGH OVER OUR REGION.
A WEAK SURGE OF MOISTURE AHEAD OF ONE WAVE IN THE FLOW WILL
TRIGGER SHOWERS EARLY SATURDAY A SECOND POTENTIAL SURGE OF
MOISTURE WITH ANOTHER WAVE COULD BRING ANOTHER CHANCE OF SHOWERS
AFTER WEDNESDAY OR THURSDAY.
&&
.NEAR TERM /UNTIL 9 AM THIS MORNING/...
RADAR SHOWS SOME LIGHT SHOWERS MOVING ACROSS PORTIONS OF WARREN
AND MCKEAN COUNTIES AND NOW INTO CLEARFIELD COUNTY. MOST OF THE
LIGHT RAIN IS NOT LIKELY REACHING THE GROUND IN MANY PLACES. A
MORE ORGANIZED BAND AREA OF RAIN IS OVER WESTERN PA AND HEADED
RAPIDLY TO THE EAST-SOUTHEAST.
THERE IS MORE RAIN TO THE WEST OVER OHIO AND WITH WESTERLY FLOW
OVER A GENERAL E-W SAGGING BOUNDARY GOING TO BE A SLOW PUSH FOR
THIS BOUNDARY TO WORK INTO SOUTHERN PA OVERNIGHT AND INTO
SATURDAY.
MOST SITES SHOW LIGHT RAIN BUT 1 OR 2 OBSERVATIONS UNDER AN
ENHANCE ECHO SHOW 3 BALL RAIN. MODIFIED GRIDS TO REFLECT THE RAIN
OVER WESTERN PA. NUDGED GRIDS TOWARD AM WITH HRRR AND BLEND
PREVIOUS GUIDANCE. STILL TRIED TO KEEP QPF LOW AND POPS IN MOST
LOCATIONS IN THE CHANCE CATEGORY AS THIS SHOULD NOT BE A
SIGNIFICANT RAINFALL. HIGHEST POPS IN THE 40-54 PERCENT RANGE SORT
OF ACROSS OUR CENTRAL AND WESTERN AREAS.
LOW PROBABILITY OF MUCH OVER 0.05 TO 0.10 INCHES BY SUNRISE AND
MOST GUIDANCE IMPLIES HIGHER POPS SLIDE TO SOUTHEAST TOWARD
SUNRISE.
&&
.SHORT TERM /9 AM THIS MORNING THROUGH 6 PM SUNDAY/...
MODELS CONTINUE TO SHOW HIGHER POPS FARTHER SOUTH NEAR MASON-DIXON
LINE AND LOWER POPS TO NORTH. SHOULD BE A LIGHT EVENT AS PW IS ON
THE LOW SIDE. TRIED TO SHOW POP GRADIENT LOWER TO NORTH AND HIGHER
TO SOUTH NEAR MD BORDER LATER IN THE DAY.
MINOR ADJUSTMENTS TO TEMPERATURES.
PREVIOUS FORECAST:
THE 18Z GEFS SHOWS BEST CHANCE RAINFALL ABOUT 8-2 PM ALONG MASON-
DIXON LINE DROPPING OFF FAST TO NORTH. HARD FOR MOST MODELS TO
CRANK OUT MORE THAN A FEW HUNDREDTHS OF A QPF. SREF FROM 15Z WAS
WETTER BUT IT TOO FOCUSED HIGHEST POPS NEAR MASON-DIXON LINE.
NORTHERN AREAS SHOULD BE RAIN FREE AND EXPECT WIDELY SCATTERED
SHOWERS AND THUNDER IN CENTRAL. SHOWERS IN SOUTHERN AREAS NEAR THE
LOW-LEVEL BOUNDARY SHOULD MOSTLY BE LIGHT AND SHOULD CLEAR MOST OF
THE AREA BY MID AFTERNOON. GOOD NEWS IS PW IS NEAR NORMAL AND
DROPS IN THE LATE AFTERNOON...PRETTY DRY COLUMN OF AIR OVER PA SO
NOT A LOT TO WORK WITH.
JUST A NOTE THAT THE WINDS QUITE STRONG AND PARALLEL TO THE
BOUNDARY IN SOUTHERN PA. IF WE GET ANY THUNDERSTORMS THEY HAVE SOME
GOOD WINDS TO TAP. GOOD NEWS IS THE CAPE IS REALLY LOW SO LARGE
UPDRAFTS ARE NOT LIKELY TO DEVELOP.
&&
.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
CONSENSUS AMONG MED RANGE GUIDANCE FOR ANOTHER STRETCH OF
COOL/DRY WX SUNDAY INTO EARLY NEXT WEEK...AS COLD FRONT PRESSES
SOUTH OF PA AND COOL...CANADIAN HIGH PRES BUILDS SE ACROSS THE
AREA. 00Z GEFS 8H TEMPS REMAIN BLW NORMAL SUN-MON WHEN DAYTIME
MAXES WILL LIKELY BE 5-10F BLW NORMAL. NEGATIVE PWAT AND 8H TEMPS
ANOMALIES IN THE ENSEMBLE OUTPUT POINT TOWARD AN IDEAL SETUP FOR
RADIATIONAL COOLING MONDAY AND TUESDAY NIGHTS...AS SFC HIGH DRIFTS
OVR THE AREA. FOR MANY PARTS OF CENTRAL PA THESE COULD BE THE
COOLEST NIGHTS OF THE SUMMER SEASON. NORTHERN MTNS WILL BE SOLIDLY
IN THE 40S...WITH LOWER TO MID 50S ELSEWHERE.
AXIS OF UPPER TROUGH SHIFTS FROM THE NORTHEAST CONUS TO THE
MIDWEST BY THE MID/LATE NEXT WEEK...INDICATING SLIGHTLY
WARMER...MORE HUMID AIR WILL MAKE A RETURN. CAN/T RULE OUT AN
ISOLD SHRA/TSRA CREEPING INTO THE SC MTNS AS EARLY AS TUE AFTN -
AS HINTED BY BOTH THE EC/GFS. HOWEVER...THE NEXT CHANCE FOR
WIDESPREAD PRECIPITATION WILL LIKELY NOT COME UNTIL LATE WED WITH
ARRIVAL OF A WARM FRONT OR AN EVEN BETTER CHANCE THURSDAY AS NEXT
COLD FRONT SLOWS AS IT PUSHES THROUGH.
&&
.AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
ALTHOUGH RADAR SHOWS A WIDESPREAD AREA OF RAIN SHOWERS CROSSING
THE REGION...LITTLE ACTIVITY REACHING THE SURFACE EXCEPT IN SOME
ISOLATED HEAVIER SHOWERS NEAR KERI.
CURRENT OBSERVATIONS ALONG WITH RAP SHORT TERM FORECASTS INDICATE
CEILINGS SHOULD REMAIN VFR TO MVFR THROUGH THE FORECAST PERIOD.
THE LATEST CALL TO THE KBFD ASOS INDICATED 1100 FT OVC. IF ANY
AIRFIELD WILL FLIRT WITH DROPPING BELOW VFR CEILINGS...THIS WOULD
BE IT.
KEPT ALL SITES IN LINE WITH CURRENT CONDITIONS WITH THE ADDITION OF
VCSH BASED ON RADAR COVERAGE.
ANY SHOWERS THAT DO REACH THE GROUND WILL BE SLIDING SOUTH THROUGH
THE MID MORNING HOURS. WITH ONLY A MARGINAL SLIVER OF CAPE
ACCOMPANYING THE PRECIP...DO NOT EXPECT CONVECTION TO DEVELOP. BY
MID AFTERNOON...PRECIP SHOULD EXIT THE AREA.
OUTLOOK...
SUN-WED...VFR. NO SIG WX. AM FOG POSSIBLE. PERHAPS
A SHOWER LATE WED.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...GRUMM
NEAR TERM...GRUMM
SHORT TERM...GRUMM/RXR
LONG TERM...RXR
AVIATION...MARTIN/TYBURSKI
FOR FREQUENTLY ASKED QUESTIONS ABOUT THE AREA FORECAST DISCUSSION
VISIT...
HTTP://WEATHER.GOV/SALTLAKECITY/GENERAL/AFD_FAQS.PHP (ALL LOWER CASE)
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
459 AM EDT SAT AUG 3 2013
.SYNOPSIS...
A COLD FRONT WILL MOVE SOUTHEAST THROUGH THE AREA LATE TODAY INTO
TONIGHT...PRECEDED AND ACCOMPANIED BY SHOWERS AND THUNDERSTORMS.
HIGH PRESSURE FOLLOWING THE FRONT WILL BRING DRIER AND COOLER AIR
BACK INTO THE REGION SUNDAY INTO MONDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 355 AM EDT SATURDAY...
SCATTERED SHOWERS CURRENTLY MOVING EAST OUT OF EASTERN KY AND WV
ON NOSE OF ISENTROPIC LIFT ZONE MAXIMIZED IN 850-700 MILLIBAR
LAYER...AND WILL LIKELY CONTINUE EAST INTO NORTHWESTERN PORTION OF
THE BLACKSBURG FORECAST AREA THROUGH THE DAYBREAK HOURS BEFORE
DISSIPATING EAST OF THE BLUE RIDGE BY MID MORNING AS AREA
ENCOUNTERS INCREASINGLY DOWNSLOPE FLOW. OTHERWISE...EXPECT TO SEE
ANY EARLY MORNING FOG IN MOUNTAIN VALLEYS...AND ACROSS SOUTHSIDE
VA INTO NORTH CENTRAL NC IN VICINITY OF OLD FRONTAL BOUNDARY
RAPIDLY DISSIPATE WITH ONSET OF DAYTIME HEATING.
TRICKY FORECAST FOR REST OF TODAY AS A COMBINATION OF WEATHER
FEATURES COMPETE FOR ATTENTION. WIDESPREAD AREA OF SHOWERS
CURRENTLY OVER OH VALLEY ASSOCIATED WITH FIRST IN SERIES OF SHORT
WAVE TROFS THAT WILL PROGRESSIVELY CARVE OUT UPPER TROF OVER THE
NORTHEASTERN PORTION OF THE NATION THIS WEEKEND...DRIVING COOL
FRONT INTO AND THROUGH THE BLACKSBURG FORECAST AREA TONIGHT. LOCAL
WRF AND HRRR MODELS INDICATING THAT PRECEDING AREA OF SHOWERS MAY
HELP GENERATE AND PUSH OUTFLOW BOUNDARY SOUTHEAST OUT AHEAD OF
THE FRONT INTO NORTHERN THIRD OF THE BLACKSBURG FORECAST AREA THIS
AFTERNOON. DESPITE RATHER LACKLUSTER MID LEVEL INSTABILITY...AND
POTENTIAL OF AT LEAST SOME OFFSET OF INSOLATIVE POTENTIAL DUE TO
LINGERING MID AND HIGH LEVEL CLOUDS...WIDELY SCATTERED TO
SCATTERED SHOWERS/THUNDERSTORMS ARE EXPECTED TO DEVELOP BY/DURING
THE EARLY TO MID AFTERNOON IN ASSOCIATED CONFLUENCE ZONE...
ESPECIALLY NORTH OF HIGHWAY 460...AND ACROSS WESTERN FLANKS OF THE
APPALACHIANS AS WESTERLY UPSLOPING WINDS PROVIDE SOME NEEDED
UPWARD ASSIST.
MUCH BETTER INSTABILITY REMAINS LOCKED UP OVER SOUTHSIDE VA INTO
NORTH CENTRAL NC WHERE MUCH DEEPER LOW LEVEL/TROPICAL MOISTURE
RESIDES IN VICINITY OF OLD FRONT. SHORT RANGE AND MESOSCALE
MODELS HIGHLIGHT THIS AREA FOR ADDITIONAL SCATTERED
SHOWER/THUNDERSTORM DEVELOPMENT...ALTHOUGH ANY NORTHWARD PUSH OF
THIS AIRMASS INTO VA APPEARS UNLIKELY CONSIDERING SLOW VEERING OF
WINDS AS ZONAL FLOW INCREASES OVER AREA.
IN LIGHT OF THE ABOVE...BEST THREAT FOR WIDELY SCATTERED TO
SCATTERED SHOWERS/THUNDERSTORMS TODAY WILL BE ACROSS THE
NORTH...NORTHWEST...AND SOUTHEAST PORTION OF THE BLACKSBURG
FORECAST AREA...WITH RELATIVE MINIMUM (MORE ISOLATED) THREAT FROM
THE FOOTHILLS OF NORTHWEST NC NORTHEAST TOWARD FARMVILLE VA.
SEVERE WEATHER THREAT AT THE PRESENT TIME APPEARS TO BE REMOTE.
LOSS OF DAYTIME HEATING AND LITTLE TO NO DYNAMIC SUPPORT AS SHORT
WAVE ENERGY REMAINS WELL NORTH OF THE BLACKSBURG AREA SHOULD
SUPPORT DEMISE OF LINGERING SHOWER/THUNDERSTORM ACTIVITY IN MOST
AREAS BEFORE MIDNIGHT TONIGHT...BUT WITH A LOW THREAT OF SOME
STRAY SHOWERS REMAINING INTO THE EARLY MORNING HOURS ACROSS THE
SOUTHWESTERN MOUNTAINS WHERE A BIT DEEPER MOISTURE PROFILE WILL
RESIDE AS COLDER AIR FOLDS INTO AREA FROM THE NORTH.
MOS GUIDANCE GENERALLY ACCEPTED FOR THE NEAR TERM PERIOD...WITH
HIGHS TODAY IN THE 70S ACROSS THE HIGHER TERRAIN TO 80S
ELSEWHERE...WITH OVERNIGHT LOWS MAINLY IN THE 60S EXCLUDING SOME
MID TO UPPER 50S IN SOME OF THE DEEPER MOUNTAIN VALLEYS.
&&
.SHORT TERM /SUNDAY THROUGH TUESDAY NIGHT/...
AS OF 430 AM EDT SATURDAY...
A BRIEF AMPLIFICATION OF THE NW FLOW ALOFT WILL ALLOW A FAIRLY
SUBSTANTIAL AREA OF COOL...DRY HIGH PRESSURE TO SPREAD SE ACROSS
THE REGION BEHIND A COLD FRONT WHICH WILL PUSH INTO SOUTH CAROLINA
BEFORE STALLING MONDAY. THIS WILL PROVIDE THE FORECAST AREA WITH
A RESPITE FROM THE INCESSANT SHRA/TSRA ACTIVITY OF RECENT DAYS AND
ALLOW A QUITE DRY AIR MASS TO SPREAD THROUGH THE AREA BY EARLY
MON. ANY REMNANT -SHRA AROUND DAYBREAK SUN...SHOULD DISSIPATE
QUICKLY AND SKIES SHOULD CLEAR EAST OF THE ALLEGHANYS. CANNOT RULE
OUT LINGERING UPSLOPE SC ACROSS SE WV...BUT OVERALL EVEN THOSE
AREAS SHOULD CLEAR OUT BY EVENING.
TEMPS SUN SHOULD BE BELOW NORMAL WEST OF THE ALLEGHANYS...BUT
NEAR NORMAL ACROSS THE PIEDMONT FROM STRONG INSOLATION AND
DOWNSLOPE NW FLOW. MON MORNING SHOULD BE THE COOLEST MORNING OF
THE NEXT SEVEN DAYS AND RIVAL THE RECENT PAST COUPLE OF COOL
SPELLS WHERE MIN TEMPS DIPPED INTO THE UPPER 40S IN DEEPER
MOUNTAIN VALLEYS WITH WIDESPREAD 50S WEST OF THE BLUE
RIDGE...LOWER 60S ACROSS THE PIEDMONT.
FOR TUE...THE FIRST IN A LONG SERIES OF NW FLOW DISTURBANCES
TRACKS ACROSS THE REGION AS A PRONOUNCED BAROCLINIC ZONE BEGINS TO
SET UP ACROSS THE REGION FROM NW-SE FROM THE OHIO VALLEY TOWARD
THE MID-ATLANTIC...BEGINNING WHAT SHOULD BE A 3-5 DAY PERIOD OF
QUITE ACTIVE CONVECTIVE WEATHER. FOR TUE...SFC MOISTURE WILL JUST
BE RECOVERING...SO NOT EXPECTING AN OVERLY ACTIVE CONVECTIVE DAY
JUST YET. THE MON SFC HIGH WILL MOVE TO A POSITION OFF THE MID-
ATLANTIC COAST AND ALLOW A WEAK WEDGE SITUATION TO EVOLVE EAST OF
THE BLUE RIDGE. FOR NOW...HAVE ADVERTISED LOW CHC POPS MOST
AREAS...BUT THE BEST THREAT FOR PCPN APPEARS TO BE EAST OF OR NEAR
THE ALLEGHANYS AT THIS TIME WHERE LOW-LEVEL MOISTURE CONVERGENCE
AND SFC TD IS MAXIMIZED AND DIFFERENTIAL HEATING MAY HELP SPARK
INITIAL CONVECTION DURING THE AFTERNOON. MAX/MIN TEMPS WILL BEGIN
TO RECOVER FROM THE MON COOL SPELL AND SHOULD BE CLOSER TO
NORMAL...EXCEPT STILL SLIGHTLY BELOW NORMAL IN THE FAR N-NW PART
OF THE CWA.
&&
.LONG TERM /WEDNESDAY THROUGH FRIDAY/...
AS OF 445 AM EDT SATURDAY...
AS NOTED THE PAST SEVERAL DAYS...THIS PERIOD LOOKS TO BE QUITE
ACTIVE WITH REGARD TO CONVECTION. THE FLOW WILL TREND TOWARD AN
INCREASINGLY ZONAL FLOW WITH A SERIES OF EMBEDDED DISTURBANCES
ALOFT. A WEAK COLD FRONT WILL BEGIN TO ENTER THE NW PART OF THE
CWA BY THU...THEN ATTEMPT TO PUSH SLOWLY SOUTHEASTWARD THU-FRI.
HOW FAR S-SE THE FRONT MOVES BEFORE STALLING IS HIGHLY
QUESTIONABLE GIVEN THE INCREASING ZONAL FLOW IN PLACE AND A
SUBTROPICAL RIDGE BUILDING ACROSS THE SE STATES. BOTH THE GFS AND
ECMWF TRY TO PUSH THE FRONT COMPLETELY SOUTH OF OUR CWA BY
SATURDAY AS IT STRENGTHENS THE NW FLOW JUST ENOUGH TO DO SO...BUT
AS NOTED...THAT IS SOMEWHAT DOUBTFUL.
AT ANY RATE...WED-THU LOOK QUITE ACTIVE AND
PROBLEMATIC...ESPECIALLY IN TERMS OF FLASH FLOOD POTENTIAL. PWATS
REACH OR EXCEED 2.0 INCHES ACROSS MUCH OF THE CWA WED- THU
AFTERNOON. THIS COMBINED WITH PERIODIC AMPLE UPPER SUPPORT FROM
EMBEDDED SHORT WAVES AND THE VERY WET ANTECEDENT CONDITIONS WILL
HAVE TO BE WATCHED VERY CAREFULLY. WITH A NEARLY STALLED OR QUASI-
STATIONARY FRONTAL BOUNDARY DRAPED ACROSS THE REGION AND FAVORABLE
SUPPORT...TRAINING OF SHRA/TSRA ACTIVITY APPEARS LIKELY.
FURTHERMORE...INSTABILITY LOOKS QUITE HEALTHY WITH CAPES REACHING
2000 J/KG OR GREATER WED AND THU AFTERNOON ACROSS MUCH OF THE CWA.
THUS...A FEW STRONG TO SEVERE THUNDERSTORMS ALSO APPEAR LIKELY.
HAVE INTRODUCED THE MENTION OF HEAVY RAIN TO THE ZFP FOR THESE
PERIODS AND WILL ALSO CONTINUE TO INCLUDE THE THREAT OF HEAVY RAIN
AND ISOLATED SEVERE IN THE HWO.
HUMIDITY LEVELS WILL BE QUITE HIGH THROUGH THE EXTENDED
PERIODS...SO THERE WILL BE LITTLE COOLING AT NIGHT. BY THE SAME
TOKEN...MAX TEMPS SHOULD REMAIN NEAR NORMAL...PERHAPS SLIGHTLY BELOW
IN AREAS THAT HAVE ENOUGH CLOUD COVER/PCPN TO LIMIT HEATING.
NONETHELESS...IT WILL BE QUITE MUGGY AND MUCH MORE UNCOMFORTABLE
THAN THE BEGINNING OF THE WEEK.
&&
.AVIATION /09Z SATURDAY THROUGH WEDNESDAY/...
AS OF 225 AM EDT SATURDAY...
VFR WEATHER EXPECTED AT ALL TERMINAL FORECAST SITES FOR THE REST
OF TONIGHT INTO SATURDAY WITH EXCEPTION OF MOUNTAIN VALLEYS...SUCH
AS AT KBCB AND KLWB...AND ACROSS SOUTHSIDE VA AT/NEAR KDAN WHERE
PROXIMITY TO OLD FRONTAL BOUNDARY AND MUCH HIGHER DEW POINTS
RESIDE...WHERE DEVELOPMENT OF PATCHY LATE NIGHT/EARLY MORNING FOG
AND ASSOCIATED LOCALIZED FLIGHT RESTRICTIONS DOWN INTO THE IFR
RANGE ARE LIKELY. FOG SHOULD RAPIDLY LIFT/MIX OUT BY 13Z/900 AM
WITH ONSET OF DAYTIME HEATING.
EARLY MORNING CONVECTION DEVELOPING OVER CENTRAL NC AS MOIST AIR
TRIES TO MAKE A PUSH BACK TOWARD THE NORTH MAY MAKE AN ATTEMPT TO
THREATEN KDAN TOWARD DAYBREAK...BUT CURRENT THINKING IS THAT
ACTUAL FLIGHT IMPACT FROM TSRA WILL REMAIN SOUTH OF THE STATE
LINE...BUT CLOSE ENOUGH TO WARRANT MORNING INCLUSION OF VCTS AT
KDAN.
APPROACH OF NEXT FRONTAL SYSTEM TO THE NORTH AND WEST...AND WEAK
QUASI-STATIONARY WARM/MOIST BOUNDARY JUST TO THE SOUTH...COUPLED
WITH INCREASING INSOLATION SHOULD BE SUFFICIENT TO SUPPORT THE
DEVELOPMENT OF WIDELY SCATTERED SHOWERS/STORMS IN JUST ABOUT ALL
AREAS THIS AFTERNOON INTO THIS EVENING...WITH ACTIVITY MAXIMIZED
NORTH OF HIGHWAY 460...ACROSS THE WESTERN FLANKS OF THE
APPALACHIANS...AND OUT ACROSS THE PIEDMONT MAINLY ALONG AND SOUTH
OF THE VA/NC STATE LINE. ACTUAL THREAT OF TSRA AT ANY TERMINAL
FORECAST POINT REMAINS TOO LOW TO WARRANT ANYTHING OTHER THAN
VCTS INCLUSION AT THE PRESENT TIME...BUT WILL AMEND AS NECESSARY
IF ANY PARTICULAR STORM THREATENS ANY OF THE AIRPORTS LATER TODAY.
ONSET OF NIGHTTIME COOLING AND PASSAGE COOL FRONT SHOULD END
THREAT OF SHOWERS/STORMS THIS EVENING IN MOST AREAS...WITH VFR
WEATHER THEN EXPECTED TO PREDOMINATE SUNDAY INTO MONDAY (OTHER
THAN TYPICAL LATE NIGHT/EARLY MORNING PATCHY FOG IN MOUNTAIN
VALLEYS AND LOW LYING SHELTERED AREAS OF THE PIEDMONT) AS HIGH
PRESSURE SETTLES INTO/OVER THE AREA. AFTERNOON CONVECTION EXPECTED
TO RETURN TO THE AREA BY TUESDAY AFTERNOON AS SURFACE RIDGE MOVES
OFF TO THE EAST AND AS SOUTHERLY WINDS RETURN TO THE
REGION...BRINGING AN INCREASE OF LOW LEVEL MOISTURE.
WEDNESDAY OFFERS THE HIGHEST THREAT FOR A MORE ORGANIZED SHRA/TSRA
EVENT ALONG WITH ATTENDANT LOWER CIGS/VSBYS AS TROPICAL MOISTURE
RETURNS TO THE AREA.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...WERT
NEAR TERM...WERT
SHORT TERM...RAB
LONG TERM...RAB/WP
AVIATION...CF/KK/WERT
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
403 AM EDT SAT AUG 3 2013
.SYNOPSIS...
A COLD FRONT WILL MOVE SOUTHEAST THROUGH THE AREA LATE TODAY INTO
TONIGHT...PRECEDED AND ACCOMPANIED BY SHOWERS AND THUNDERSTORMS.
HIGH PRESSURE FOLLOWING THE FRONT WILL BRING DRIER AND COOLER AIR
BACK INTO THE REGION SUNDAY INTO MONDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 355 AM EDT SATURDAY...
SCATTERED SHOWERS CURRENTLY MOVING EAST OUT OF EASTERN KY AND WV
ON NOSE OF ISENTROPIC LIFT ZONE MAXIMIZED IN 850-700 MILLIBAR
LAYER...AND WILL LIKELY CONTINUE EAST INTO NORTHWESTERN PORTION OF
THE BLACKSBURG FORECAST AREA THROUGH THE DAYBREAK HOURS BEFORE
DISSIPATING EAST OF THE BLUE RIDGE BY MID MORNING AS AREA
ENCOUNTERS INCREASINGLY DOWNSLOPE FLOW. OTHERWISE...EXPECT TO SEE
ANY EARLY MORNING FOG IN MOUNTAIN VALLEYS...AND ACROSS SOUTHSIDE
VA INTO NORTH CENTRAL NC IN VICINITY OF OLD FRONTAL BOUNDARY
RAPIDLY DISSIPATE WITH ONSET OF DAYTIME HEATING.
TRICKY FORECAST FOR REST OF TODAY AS A COMBINATION OF WEATHER
FEATURES COMPETE FOR ATTENTION. WIDESPREAD AREA OF SHOWERS
CURRENTLY OVER OH VALLEY ASSOCIATED WITH FIRST IN SERIES OF SHORT
WAVE TROFS THAT WILL PROGRESSIVELY CARVE OUT UPPER TROF OVER THE
NORTHEASTERN PORTION OF THE NATION THIS WEEKEND...DRIVING COOL
FRONT INTO AND THROUGH THE BLACKSBURG FORECAST AREA TONIGHT. LOCAL
WRF AND HRRR MODELS INDICATING THAT PRECEDING AREA OF SHOWERS MAY
HELP GENERATE AND PUSH OUTFLOW BOUNDARY SOUTHEAST OUT AHEAD OF
THE FRONT INTO NORTHERN THIRD OF THE BLACKSBURG FORECAST AREA THIS
AFTERNOON. DESPITE RATHER LACKLUSTER MID LEVEL INSTABILITY...AND
POTENTIAL OF AT LEAST SOME OFFSET OF INSOLATIVE POTENTIAL DUE TO
LINGERING MID AND HIGH LEVEL CLOUDS...WIDELY SCATTERED TO
SCATTERED SHOWERS/THUNDERSTORMS ARE EXPECTED TO DEVELOP BY/DURING
THE EARLY TO MID AFTERNOON IN ASSOCIATED CONFLUENCE ZONE...
ESPECIALLY NORTH OF HIGHWAY 460...AND ACROSS WESTERN FLANKS OF THE
APPALACHIANS AS WESTERLY UPSLOPING WINDS PROVIDE SOME NEEDED
UPWARD ASSIST.
MUCH BETTER INSTABILITY REMAINS LOCKED UP OVER SOUTHSIDE VA INTO
NORTH CENTRAL NC WHERE MUCH DEEPER LOW LEVEL/TROPICAL MOISTURE
RESIDES IN VICINITY OF OLD FRONT. SHORT RANGE AND MESOSCALE
MODELS HIGHLIGHT THIS AREA FOR ADDITIONAL SCATTERED
SHOWER/THUNDERSTORM DEVELOPMENT...ALTHOUGH ANY NORTHWARD PUSH OF
THIS AIRMASS INTO VA APPEARS UNLIKELY CONSIDERING SLOW VEERING OF
WINDS AS ZONAL FLOW INCREASES OVER AREA.
IN LIGHT OF THE ABOVE...BEST THREAT FOR WIDELY SCATTERED TO
SCATTERED SHOWERS/THUNDERSTORMS TODAY WILL BE ACROSS THE
NORTH...NORTHWEST...AND SOUTHEAST PORTION OF THE BLACKSBURG
FORECAST AREA...WITH RELATIVE MINIMUM (MORE ISOLATED) THREAT FROM
THE FOOTHILLS OF NORTHWEST NC NORTHEAST TOWARD FARMVILLE VA.
SEVERE WEATHER THREAT AT THE PRESENT TIME APPEARS TO BE REMOTE.
LOSS OF DAYTIME HEATING AND LITTLE TO NO DYNAMIC SUPPORT AS SHORT
WAVE ENERGY REMAINS WELL NORTH OF THE BLACKSBURG AREA SHOULD
SUPPORT DEMISE OF LINGERING SHOWER/THUNDERSTORM ACTIVITY IN MOST
AREAS BEFORE MIDNIGHT TONIGHT...BUT WITH A LOW THREAT OF SOME
STRAY SHOWERS REMAINING INTO THE EARLY MORNING HOURS ACROSS THE
SOUTHWESTERN MOUNTAINS WHERE A BIT DEEPER MOISTURE PROFILE WILL
RESIDE AS COLDER AIR FOLDS INTO AREA FROM THE NORTH.
MOS GUIDANCE GENERALLY ACCEPTED FOR THE NEAR TERM PERIOD...WITH
HIGHS TODAY IN THE 70S ACROSS THE HIGHER TERRAIN TO 80S
ELSEWHERE...WITH OVERNIGHT LOWS MAINLY IN THE 60S EXCLUDING SOME
MID TO UPPER 50S IN SOME OF THE DEEPER MOUNTAIN VALLEYS.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY/...
AS OF 245 PM EDT FRIDAY...
DRIER AIR ARRIVES SUNDAY AFTERNOON ON NW FLOW AND SHOULD SEE
INCREASING SUNSHINE. HIGH PRESSURE ARRIVES SUN NIGHT INTO THE
CENTRAL APPALACHIANS AND THEN SHIFTS TO THE MID ATLANTIC COAST BY
THE END OF THE DAY. NOTICING ENOUGH CONVERGENCE TOWARD MONDAY
AFTERNOON TO SQUEEZE OUT SOME SHOWERS IN THE NC MTNS.
LOOKS LIKE TEMPS WILL BE WARM SAT NIGHT WITH LOWER 60S MOUNTAINS TO
MID TO UPPER 60S EAST.
SUNDAY WILL BE MILD/WARM WITH NW WINDS AROUND 10 MPH WITH SHOWERS
SHIFTING SOUTH AND DEWPOINTS DROPPING INTO THE 50S. ANTICIPATING
HIGHS FROM THE 70S MOUNTAINS TO LOWER TO MID 80S EAST OF THE BLUE
RIDGE.
SUNDAY NIGHT WILL BE COOLER WITH LOWS IN THE 50S MOUNTAINS AND
FOOTHILLS...WITH LOWER 60S SOUTHEAST.
MOISTURE WILL START TO INCREASE SOME MONDAY AFTERNOON BUT EXPECT THE
DEWPOINTS TO STILL BE IN THE 50S. HIGHS ARE GOING TO RANGE FROM THE
MID 70S SOUTHEAST WV/NC MTNS TO AROUND 80 NEW RIVER
VALLEY/ROANOKE...AND LOWER 80S FOOTHILLS-PIEDMONT.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
AS OF 1205 PM EDT FRIDAY...
FORECAST LOOKING SOMEWHAT UNSETTLED AS BROAD TROUGH OVER THE GREAT
LAKES AND NORTHEAST SENDS A FRONT OR TWO DOWN MID TO LATE WEEK. FOR
MONDAY NIGHT AND TUESDAY...HIGH PRESSURE WILL BE SITUATED ACROSS THE
MID ATLANTIC AND PUTTING US IN A E-SE FLOW WITH WEDGING POTENTIAL.
MONDAY NIGHT WILL SEE SOME RETURN MOISTURE BANKING UP INTO THE
SOUTHERN BLUE RIDGE SO HAVE SLIGHT CHANCE OF SHOWERS THERE. DURING
TUESDAY THE FLOW GOES MORE SE-S SO THETA-E RIDGING ACROSS THE BLUE
RIDGE AND EAST WHICH WILL HELP IN THE DEVELOPMENT OF SCATTERED
SHOWERS AND STORMS...WITH LESS COVERAGE IN WV. WITH A WEAK SFC-8H
FLOW GOING FROM SOUTH TO SW AND NW FLOW ALOFT...SOME OF THE STORMS
COULD BE SLOW MOVERS LEADING TO HEAVY RAIN.
THE MIDDLE OF THE WEEK SHOWS SURFACE HIGH OVER THE WRN ATLANTIC WITH
THE SFC FLOW BECOMING OVERALL MORE SW TO WEST. SEVERAL IMPULSES
ALONG THE SRN FRINGE OF THE WESTERLIES WILL BE MOVING FROM THE OHIO
VALLEY INTO THE MID ATLANTIC AND BRING A BETTER THREAT OF STORMS
DURING THE DAY WITH SOME IN THROUGH THE NIGHT. THE UPPER PATTERN
BECOMES MORE ZONAL DURING THE WED-FRI TIME FRAME WITH 5H HEIGHTS
RISING TO 588 TO 591 DM AND PUTTING US MORE IN TYPICAL SUMMER
HUMIDITY. THE NEXT FRONT LOOKS TO ARRIVE ACROSS OUR NECK OF THE
WOODS THU-FRI BUT EXPECTING IT TO STALL AS IT BECOMES PARALLEL TO
THE FLOW ALOFT. THIS POTENTIALLY COULD BRING OUR FORECAST AREA INTO
A PROLONGED PERIOD OF OFF AND ON STORMS. THE SAVING GRACE WILL BE
THE FLOW ALOFT WILL BE WESTERLY AND NOT DRAWING AS MUCH MOISTURE
FROM THE GULF.
FOR TEMPS WILL GO A LITTLE UNDER GUIDANCE EARLY IN THE PIEDMONT WEST
TO THE NEW RIVER VALLEY WITH WEDGE LIKE SETUP AND CLOUDS. WILL WARM
UP LOWS AND HIGHS BY MIDWEEK BUT EVEN THEN SHOULD BE CLOSE TO NORMAL
FOR EARLY AUGUST. CLOUD COVER MAY KEEP HIGHS DOWN SOMEWHAT IF WE GET
CONVECTIVE BLOWOFF.
&&
.AVIATION /08Z SATURDAY THROUGH WEDNESDAY/...
AS OF 225 AM EDT SATURDAY...
VFR WEATHER EXPECTED AT ALL TERMINAL FORECAST SITES FOR THE REST
OF TONIGHT INTO SATURDAY WITH EXCEPTION OF MOUNTAIN VALLEYS...SUCH
AS AT KBCB AND KLWB...AND ACROSS SOUTHSIDE VA AT/NEAR KDAN WHERE
PROXIMITY TO OLD FRONTAL BOUNDARY AND MUCH HIGHER DEW POINTS
RESIDE...WHERE DEVELOPMENT OF PATCHY LATE NIGHT/EARLY MORNING FOG
AND ASSOCIATED LOCALIZED FLIGHT RESTRICTIONS DOWN INTO THE IFR
RANGE ARE LIKELY. FOG SHOULD RAPIDLY LIFT/MIX OUT BY 13Z/900 AM
WITH ONSET OF DAYTIME HEATING.
EARLY MORNING CONVECTION DEVELOPING OVER CENTRAL NC AS MOIST AIR
TRIES TO MAKE A PUSH BACK TOWARD THE NORTH MAY MAKE AN ATTEMPT TO
THREATEN KDAN TOWARD DAYBREAK...BUT CURRENT THINKING IS THAT
ACTUAL FLIGHT IMPACT FROM TSRA WILL REMAIN SOUTH OF THE STATE
LINE...BUT CLOSE ENOUGH TO WARRANT MORNING INCLUSION OF VCTS AT
KDAN.
APPROACH OF NEXT FRONTAL SYSTEM TO THE NORTH AND WEST...AND WEAK
QUASI-STATIONARY WARM/MOIST BOUNDARY JUST TO THE SOUTH...COUPLED
WITH INCREASING INSOLATION SHOULD BE SUFFICIENT TO SUPPORT THE
DEVELOPMENT OF WIDELY SCATTERED SHOWERS/STORMS IN JUST ABOUT ALL
AREAS THIS AFTERNOON INTO THIS EVENING...WITH ACTIVITY MAXIMIZED
NORTH OF HIGHWAY 460...ACROSS THE WESTERN FLANKS OF THE
APPALACHIANS...AND OUT ACROSS THE PIEDMONT MAINLY ALONG AND SOUTH
OF THE VA/NC STATE LINE. ACTUAL THREAT OF TSRA AT ANY TERMINAL
FORECAST POINT REMAINS TOO LOW TO WARRANT ANYTHING OTHER THAN
VCTS INCLUSION AT THE PRESENT TIME...BUT WILL AMEND AS NECESSARY
IF ANY PARTICULAR STORM THREATENS ANY OF THE AIRPORTS LATER TODAY.
ONSET OF NIGHTTIME COOLING AND PASSAGE COOL FRONT SHOULD END
THREAT OF SHOWERS/STORMS THIS EVENING IN MOST AREAS...WITH VFR
WEATHER THEN EXPECTED TO PREDOMINATE SUNDAY INTO MONDAY (OTHER
THAN TYPICAL LATE NIGHT/EARLY MORNING PATCHY FOG IN MOUNTAIN
VALLEYS AND LOW LYING SHELTERED AREAS OF THE PIEDMONT) AS HIGH
PRESSURE SETTLES INTO/OVER THE AREA. AFTERNOON CONVECTION EXPECTED
TO RETURN TO THE AREA BY TUESDAY AFTERNOON AS SURFACE RIDGE MOVES
OFF TO THE EAST AND AS SOUTHERLY WINDS RETURN TO THE
REGION...BRINGING AN INCREASE OF LOW LEVEL MOISTURE.
WEDNESDAY OFFERS THE HIGHEST THREAT FOR A MORE ORGANIZED SHRA/TSRA
EVENT ALONG WITH ATTENDANT LOWER CIGS/VSBYS AS TROPICAL MOISTURE
RETURNS TO THE AREA.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...WERT
NEAR TERM...WERT
SHORT TERM...WP
LONG TERM...WP
AVIATION...CF/KK/WERT
AREA FORECAST DISCUSSION...UPDATED
NWS SPOKANE WA
1038 PM PDT Fri Aug 2 2013
.SYNOPSIS...
Unsettled weather will continue this evening with rain showers
and a few thunderstorms. Lingering showers will be common near
the Canadian border through Saturday. Summer weather will return
next week with a warm up back to normal and small chances of
mainly mountain thunderstorms each day.
&&
.DISCUSSION...
Update this evening was to increase chance of rain overnight
across the basin. HRRR has been consistent the last several runs
of keeping rain going across the basin through the night. It also has
shown very little precip across extreme northeast WA and north ID
as well as Lewiston and areas southeast towards the Camas Prairie
overnight. So adjusted accordingly and lowered chance of precip.
Cannot discount an isolated shower anywhere given the proximity of
the low. Low temps look to be on track, about 2-5 degrees below
average for this time of the year. It was quite a chilly day
today. Looks like we start to rebound tomorrow, although we will
still be about 10 degrees below average.
Nisbet
&&
.AVIATION...
06Z TAFS...VFR expected at all TAF sites. -RA will continue from the
Spokane area south and west towards the Tri Cities through the
overnight hours. Given the recent rains, patchy fog is possible at
TAF sites, and anywhere that received decent amts of rain, but
wasn`t confident enough to add it to the TAFs. Showers will once
again form across the northern mtns near 17z Sat.
&&
.PRELIMINARY POINT TEMPS/POPS...
Spokane 55 74 57 84 61 87 / 40 30 10 10 10 10
Coeur d`Alene 53 74 53 83 55 85 / 30 40 10 10 10 10
Pullman 50 74 49 83 50 87 / 20 20 10 10 10 10
Lewiston 56 82 59 92 62 94 / 10 10 10 10 10 10
Colville 52 78 52 87 52 87 / 20 40 20 20 10 10
Sandpoint 51 71 47 81 49 82 / 30 60 30 10 10 20
Kellogg 50 74 51 82 54 84 / 40 40 10 10 10 10
Moses Lake 59 81 58 89 61 92 / 60 10 10 10 0 10
Wenatchee 61 81 61 90 65 92 / 50 20 10 10 0 10
Omak 60 84 57 89 59 92 / 50 30 20 20 20 10
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...None.
&&
$$
AREA FORECAST DISCUSSION
NWS MIAMI FL
959 AM EDT SAT AUG 3 2013
.UPDATE...
MADE SOME EARLIER MINOR ADJUSTMENTS BASED ON CURRENT TRENDS, BUT
CURRENT THINKING HAS NOT CHANGED WITH CONVECTION STILL EXPECTED BY
THIS AFTERNOON. ALREADY HAVE HAD SOME ISOLATED THUNDER MOVE ONTO
THE SOUTHWEST COAST WITH THE 12Z MFL SOUNDING INDICATING A
SOUTHWEST STEERING FLOW WHICH CAME BE NO SURPRISE WITH FORECAST
SOUNDING HAVING SHOWN THAT ALSO. AS WAS THE CASE YESTERDAY, THE
ONLY FLY IN THE OINTMENT MIGHT BE CONVECTIVE DEBRIS FIELD WORKING
ITS WAY ONTO THE SOUTHEAST COASTAL REGION THIS MORNING WHICH MAY
LEAD TO LIMITED CONVECTIVE DEVELOPMENT. THE HRRR HAS NOT DEPICTED
WELL THE STORMS MOVING INTO MAINLAND MONROE COUNTY, BUT OVERALL
ITS ANALYSIS OVER THE ATLANTIC HAS BEEN GOOD. IT SHOWS SHOWERS
BEGINNING TO FORM AFTER 16Z ACROSS MOST OF THE SOUTH FLORIDA AND
THEN EXPANDING THROUGH THE AFTERNOON. GIVEN THE INSTABILITY
DEPICTED FROM THE MORNING ATMOSPHERE PROFILE, THIS APPEARS AS
REASONABLE WITH THE LOW LEVELS AFTER WARMING SURFACE TEMPERATURES
BECOMING VERY UNSTABLE. THE MID LEVEL LAPSE RATES ARE STILL NOT
IMPRESSIVE SO THE MAIN THREAT WILL CONTINUE TO BE LOCALLY HEAVY
RAIN BUT ISOLATED STRONG WIND GUSTS AND EVEN A WATERSPOUT WILL BE
POSSIBLE FROM THE STRONGER STORMS THAT COULD MATERIALIZE.
KOB
&&
.PREV DISCUSSION... /ISSUED 736 AM EDT SAT AUG 3 2013/
AVIATION...
SCATTERED SHRA/TSRA ARE EXPECTED TO DEVELOP ACROSS SOUTH
FL TODAY. PLACED VCTS ALL TERMINALS FOR THE AFTERNOON WHEN
TSTORMS WILL BE MOST PREVALENT. IFR IS POSSIBLE AT ANY GIVEN
TERMINAL, BUT IT WOULD BE BRIEF AND CONFIDENCE IS TOO LOW TO PLACE
ANYTHING MORE THAN VCTS AT THIS TIME. LIGHT-CALM WINDS THIS
MORNING ARE FORECAST TO BECOMING S-SE EAST COAST (EXCEPT LIKELY
REMAINING SW AT KTMB) AND SW AT KAPF AT 5-10 KT, THEN CALM
TONIGHT. /DG
PREV DISCUSSION... /ISSUED 351 AM EDT SAT AUG 3 2013/
DISCUSSION...
SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS WERE ALREADY
DEVELOPING EARLY THIS MORNING ACROSS THE ATLANTIC AND GULF
WATERS...WITH A FEW SHOWERS AND STORMS ALSO DEVELOPING OVER LAND.
THE REMNANTS OF DORIAN WERE LOCATED EAST OF MELBOURNE THIS
MORNING...AND THE SYSTEM WAS SHOWING SIGNS OF REDEVELOPING. MODEL
GUIDANCE IS INDICATING THAT THE TAIL OF THE DEVELOPING LOW
PRESSURE WILL REMAIN ACROSS THE LOCAL ATLANTIC WATERS AND ACROSS
SOUTH FLORIDA TODAY AS THE SYSTEM MOVES SLOWLY OFF TO THE NORTH
AND NORTHEAST. MAV GUIDANCE FOR POPS SEEMS TOO LOW CONSIDERING THE
DEVELOPMENT ACROSS THE REGION ALREADY THIS MORNING SO WENT CLOSER
TO THE MET GUIDANCE FOR POPS. HOWEVER...IT IS POSSIBLE THE
MID/UPPER LEVEL CLOUDINESS COULD LIMIT CONVECTION. IN
ADDITION...THE REGION IS ON THE SUBSIDENCE SIDE OF THE LOW. A
LIGHT WEST TO SOUTHWEST FLOW IS EXPECTED TO CONTINUE ACROSS THE
REGION TODAY...AND WITH SEA BREEZE BOUNDARIES POSSIBLY DEVELOPING
THIS AFTERNOON...THE FORECAST IS FOR SCATTERED SHOWERS AND
THUNDERSTORMS ACROSS THE REGION. STORM MOTION IS EXPECTED TO BE
SLOW TO THE EAST AND NORTHEAST. LOCALLY HEAVY RAIN IS POSSIBLE AS
PRECIPITABLE WATER VALUES REMAIN ABOVE 2 INCHES. A FEW STORMS
COULD ALSO BECOME STRONG. WITH THE LIGHT FLOW...WATERSPOUTS ARE
POSSIBLE OVER ALL OF THE LOCAL WATERS TODAY.
THE LOW PRESSURE IS FORECAST TO MERGE WITH A TROUGH TONIGHT THAT
WILL MOVE OFF THE EAST COAST. THE TAIL END MAY REMAIN OVER SOUTH
FLORIDA THROUGH MIDNIGHT BEFORE BEGINNING TO DIMINISH. SO
ISOLATED SHOWERS AND STORMS ARE POSSIBLE ACROSS THE REGION. LIGHT
WESTERLY FLOW WILL CONTINUE THROUGH MONDAY AS HIGH PRESSURE
REMAINS SOUTH OF THE REGION AND A TROUGH REMAINS OVER THE EASTERN
SEABOARD AND WESTERN ATLANTIC. THIS WILL LEAD TO SCATTERED
AFTERNOON CONVECTION EACH DAY. THE WESTERLY WINDS MAY LEAD TO
TEMPERATURES REACHING A COUPLE DEGREES ABOVE NORMAL EACH DAY
ACROSS THE EAST.
THE TROUGH WILL BEGIN TO LIFT OUT ON TUESDAY...AND HIGH PRESSURE
WILL SLOWLY BUILD ACROSS THE WESTERN ATLANTIC...WITH THE RIDGE
AXIS PUSHING NORTH OF THE REGION BY THE MIDDLE OF THE WEEK. TUESDAY
WILL BE A TRANSITION DAY AS THE RIDGE AXIS MOVES OVERHEAD...WITH
VERY LIGHT WINDS CONTINUING AND SCATTERED STORMS POSSIBLE ANYWHERE
ACROSS THE REGION. EASTERLY FLOW IS FORECAST TO REESTABLISH ITSELF
BY MIDWEEK...WITH STORMS CONCENTRATING ACROSS THE INTERIOR AND
EAST WEDNESDAY AND THURSDAY. AN UPPER LEVEL LOW MAY APPROACH THE
REGION BY THE END OF THE WEEK OR NEXT WEEKEND...AND THIS COULD
ENHANCE SHOWER AND THUNDERSTORM ACTIVITY ONCE AGAIN.
AVIATION...
A FEW SHOWERS ARE DEVELOPING IN THE VICINITY OF KAPF
SO PLACED VCSH THERE OVERNIGHT. THERE IS A LESSER CHANCE ALONG THE
ATLANTIC COAST EARLY THIS MORNING. SCATTERED SHRA/TSRA IS
EXPECTED TO DEVELOP DURING THE AFTERNOON ACROSS SOUTH FL, SO
PLACED VCTS ALL TERMINALS THEN. IFR IS POSSIBLE AT ANY GIVEN
TERMINAL, BUT IT WOULD BE BRIEF AND CONFIDENCE IS TOO LOW TO PLACE
ANYTHING MORE THAN VCTS FOR THIS AFTERNOON AT THIS TIME. LIGHT-
CALM WINDS THIS MORNING ARE FORECAST TO BECOMING S-SE EAST COAST
(EXCEPT LIKELY REMAINING SW AT KTMB) AND SW AT KAPF AT 5-10 KT.
/GREGORIA
MARINE...
A RATHER TRANQUIL MARINE FORECAST WITH THE REMNANTS OF DORIAN
CONTINUING TO MOVE NORTH OF THE LOCAL WATERS OVER THE WEEKEND.
HOWEVER...THERE COULD BE LOCALLY ROUGH SEAS NEAR STRONGER STORMS
THAT MOVE ACROSS THE LOCAL WATERS TODAY.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 90 76 93 77 / 50 20 30 10
FORT LAUDERDALE 89 78 91 78 / 50 20 20 10
MIAMI 91 78 93 78 / 50 20 30 10
NAPLES 90 76 90 76 / 30 20 20 10
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
Area Forecast Discussion
National Weather Service Lincoln IL
956 AM CDT Sat Aug 3 2013
.DISCUSSION...
ISSUED 956 AM CDT Sat Aug 3 2013
Cold front has settled into south-central Illinois this
morning...with latest obs showing it just south of I-70. To the
south of the front...mostly cloudy and humid conditions prevail
across southeast Illinois where dewpoints are hovering around 70
degrees. Meanwhile...a cooler/drier airmass has settled into much
of central Illinois north of the boundary...as evidenced by
14z/9am dewpoints in the upper 50s/lower 60s across the northern
KILX CWA. HRRR model suggests the potential for isolated
showers/thunder in the vicinity of the slow-moving cold front
today. No evidence is seen of this yet...as main precip event is
ongoing much further south across the Ozarks. Given high dewpoint
air and presence of boundary...will maintain slight chance POPs
south of I-70 throughout the day. Further north...made some
changes to sky cover to feature sunnier conditions. Also raised
afternoon highs by a degree or two. Zone update has already been
issued.
BARNES
&&
.AVIATION...
ISSUED 640 AM CDT Sat Aug 3 2013
The showers associated with the cold front have advanced east of
all the terminal sites, so no mention of precip is in any of the
tafs. We did add some mvfr fog to KSPI, but none of the other taf
sites were experiencing fog, nor are expected to this morning.
Weak high pressure advancing into central IL behind the front will
help to clear out low clouds, and provide light north-northeast
winds. High cirrus clouds from a storm complex in Missouri will
cover our area this morning, but mostly sunny skies should develop
by afternoon.
Forecast soundings are not strong on fog indicators for late
tonight, so we did not include any mention of fog at the end of
this taf period.
SHIMON
&&
.PREV DISCUSSION...
ISSUED 330 AM CDT Sat Aug 3 2013
SHORT TERM...Today through Monday night
00z short range models are in fair agreement this weekend and then
diverge during next work week as more unsettled weather pattern
sets up across IL. Will use a blend for this forecast package with
handling weather systems during next week.
A frontal boundary was pushing southeast toward I-70 in central IN
and southeast IL into central MO early this morning. Showers have been
diminishing over east central IL past couple of hours and brought
up to half to 1 inch rains to some areas from I-74 north since Friday
evening. Cold front to push through southeast IL during this morning
and have isolated showers and thunderstorms in southeast IL
today, mainly this morning. Clouds to decrease from north to south
during the day as skies become partly to mostly sunny with northern
areas enjoying more sunshine today. Less humid air filters into
northern areas as dewpoints slip into the lower 60s while
southeast IL stays humid today with dewpoints in the upper 60s and
lower 70s. Highs in the lower 80s today with Lawrenceville around 85F.
1024 mb high pressure over Saskatchewan and western Manitoba into ND
to settle southeast into the Midwest during this weekend...and be over
northeast IL by Sunday morning. This to bring fair weather to the region
today and Sunday with mostly clear skies and more comfortable humidity
levels. Lows tonight in the mid to upper 50s and highs Sunday in the
upper 70s and lower 80s with dewpoints in the upper 50s and lower 60s.
Have slight chance of showers and thunderstorms after midnight Sunday
night over western areas due to waa pattern setting up as high pressure
drifts east of IL across the Ohio Valley. Slight chance of showers
and thunderstorms gradually spreads east across the area during Monday
and Monday night in WAA pattern.
LONG TERM...Tuesday through Saturday
A rather unsettled weather pattern expected during Tuesday through
Friday across central and southeast IL as disturbances in wnw
upper level flow track across the midwest and interact with a warmer
and more humid air mass during middle of next week. Increased temps
a few degrees Tue & Wed. Best chances of showers and thunderstorms
appears to be Tuesday night after midnight through Wed and shifting
into southern areas during Wed night and Thu as a cold front slips
southward through the region. Cooler temperatures expected later next
week with dry weather returning by weeks end on Friday night & Sat.
07
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS DULUTH MN
653 AM CDT SAT AUG 3 2013
.AVIATION...12Z TAFS...LIFR-IFR CIGS/VSBYS IN FOG WILL IMPROVE TO
VFR CONDTIONS BY MID-MORNING. ELSEWHERE...AN AREA OF HIGH PRESSURE
WILL DOMINATE THE WEATHER THROUGH SUNDAY. VFR CONDTIONS WILL BE
ALL ALL SITES THROUGH SUNDAY AFTERNOON. THERE MAY BE SOME MVFR
VSBYS IN FOG AT SOME STIES EARLY SUNDAY MORNING.
&&
.PREV DISCUSSION... /ISSUED 303 AM CDT SAT AUG 3 2013/
SHORT TERM.../THROUGH TONIGHT/
AT 300AM/0800Z...SURFACE HIGH PRESSURE WAS CENTERED OVER CENTRAL
SASKATCHEWAN AND MANITOBA. THE AXIS OF A MID/UPPER LEVEL RIDGE
STRETCHED ACROSS THE WESTERN PLAINS. A SHORTWAVE NEAR THE
MONTANA/NORTH DAKOTA BORDER WAS MOVING EAST AS IT ROUNDED THE
RIDGE...AND IT WAS BRINGING BKN/OVC MID/UPPER LEVEL CLOUDS ACROSS
NORTH DAKOTA INTO NORTHERN MINNESOTA. A MID/UPPER LEVEL LOW WAS
NEAR SW HUDSON BAY. BKN/OVC LOW CLOUDS COVERED MUCH OF NORTHERN
ONTARIO...BUT WERE SLOWLY APPROACHING THE CANADA/MINNESOTA BORDER.
MOST OF THE NORTHLAND HAD CLEAR SKIES EXCEPT FOR THE WESTERN
FORECAST AREA DUE TO THE FEW/SCT MID/UPPER LEVEL CLOUDS ASSOCIATED
WITH THE APPROACHING SHORTWAVE BEGINNING WORKING THEIR WAY INTO
THE NORTHLAND. THE SURFACE WINDS WERE NEARLY CALM OR VERY LIGHT
FROM THE WNW. TEMPERATURES RANGED FROM THE MID 40S TO LOW 50S.
TODAY...THE CENTER OF THE SURFACE HIGH PRESSURE IN CANADA WILL
MOVE INTO THE RED RIVER VALLEY REGION BY LATE THIS AFTERNOON. THE
NORTHLAND CAN EXPECT PARTLY SUNNY SKIES. THERE WILL BE SOME
MID/UPPER LEVEL CLOUDS ASSOCIATED WITH THE SHORTWAVE IN NORTH
DAKOTA THAT WILL CUT ACROSS NORTHERN MINNESOTA THIS MORNING...AS
WELL AS SCATTERED CUMULUS THAT WILL DEVELOP BY LATE THIS MORNING
DUE TO THE LOW CONVECTIVE TEMPERATURES IN THE COOL NW FLOW. HIGH
TEMPERATURES SHOULD RANGE FROM THE UPPER 60S TO MID 70S.
TONIGHT...THE CENTER OF THE HIGH PRESSURE SYSTEM WILL MOVE THROUGH
THE NORTHLAND. THIS WILL BRING CALM WINDS AND CLEAR SKIES TO THE
REGION. THERE COULD BE PATCHY FOG...BUT SINCE THE SOUNDINGS AND
MODEL FORECAST SURFACE CONDENSATION PRESSURE DEFICITS DO NOT
PROVIDE ENOUGH SUGGESTION OF FOG...I LEFT IT OUT OF THE FORECAST
AT THIS POINT. THE DAY SHIFT MAY NEED TO ADD PATCHY FOG TO THE
FORECAST. OVERNIGHT LOWS SHOULD BE IN THE LOW TO UPPER 40S ACROSS
MOST OF THE REGION. I WOULD NOT BE SURPRISED IF ISOLATED LOCATIONS
ACROSS NORTHERN MINNESOTA GET INTO THE UPPER 30S.
LONG TERM.../SUNDAY - FRIDAY/
THE AREA OF HIGH PRESSURE WILL
BRING ANOTHER DAY OF QUIET CONDITIONS ACROSS THE REGION ON SUNDAY.
THE NEXT SHOT OF PRECIPITATION WILL COME MONDAY THROUGH TUESDAY
WHEN A LOW PRESSURE CENTER MOVES THROUGH SOUTHERN CANADA ALONG
WITH A SHORTWAVE THAT MOVE THROUGH NRN MN MONDAY AND TUESDAY
MORNING WHICH WILL BRING SHOWERS AND THUNDERSTORMS TO THE FORECAST
AREA. THERE WILL BE BREAK TUESDAY MORNING BEFORE THE LOW DRAGS A
FRONT THROUGH THE REGION TUESDAY AFTERNOON AND EVENING BRINGING
ANOTHER CHANCE FOR THUNDERSTORMS. AFTER THE FRONT PASSES...COOLER
THAN NORMAL TEMPS WILL FLOW INTO THE REGION FOR THE REST OF THE
WEEK WITH LITTLE PRECIPITATION EXPECTED THROUGH THE PERIOD.
AVIATION.../06Z TAF ISSUANCE/
MAINLY VFR CONDITIONS WILL OCCUR THROUGH THE PERIOD. THERE MAY BE
SOME PATCHY FOG TONIGHT WITH VSBYS DROPPING TO IFR...AND WE HAVE
THAT IN THE KBRD/KHIB/KHYR TAFS ATTM. BROKEN CEILINGS FROM 5-8KFT
WILL BE POSSIBLE OVER THE ARROWHEAD AND BORDER REGION
TONIGHT...BUT BOTH THE RAP AND NAM SUGGEST IT WILL BE MOSTLY
SCATTERED BY LATE TONIGHT. WE EXPECT MORE SCATTERED TO BROKEN VFR
CUMULUS TO FORM ON SATURDAY WITH SOME HEATING.
&&
.POINT TEMPS/POPS...
DLH 72 50 74 50 / 0 0 10 10
INL 69 42 72 49 / 0 0 10 10
BRD 74 49 75 57 / 0 0 10 30
HYR 73 44 73 52 / 0 0 10 10
ASX 73 47 74 51 / 0 0 10 10
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
LS...NONE.
&&
$$
SHORT TERM...GROCHOCINSKI
LONG TERM....STEWART
AVIATION...STEWART
AREA FORECAST DISCUSSION
NWS RALEIGH NC
958 AM EDT SAT AUG 3 2013
.SYNOPSIS...
AS A WEAK FRONT LIES OVER THE AREA...ANOTHER...STRONGER COLD FRONT
APPROACHES FROM THE NORTHWEST. THIS FRONT WILL PASS THROUGH THE
REGION SUNDAY. HIGH PRESSURE BUILDS IN BEHIND THE FRONT MONDAY
BEFORE MOVING OFF THE MID-ATLANTIC COAST TUESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 955 AM SATURDAY...
UPDATE: EARLIER SHOWERS IN THE SOUTHEAST HAVE ENDED AND LIGHT SHOWER
ACTIVITY HAS FORMED ON A SECONDARY BOUNDARY ACROSS THE NORTHWEST
PIEDMONT. BASED ON SURFACE ANALYSIS IT DOES APPEAR THAT THE ORIGINAL
BOUNDARY HAS WASHED OUT A BIT BUT IS POISED TO MAKE A COMEBACK LATER
THIS AFTERNOON AS A SMALL SHEAR AXIS EXISTS BETWEEN THE SANDHILLS
AND COASTAL PLAIN AND THIS COULD BE A FOCUS FOR SHOWER AND
THUNDERSTORM ACTIVITY THIS AFTERNOON. THEREFORE HAVE REMOVED POPS IN
THE SOUTHEAST THIS MORNING AND REPLACED THEM WITH SLIGHT CHANCE IN
THE NORTHERN TIER. HAVE LEFT POPS IN THE SOUTHEAST FOR THIS
AFTERNOON. AS FAR AS TEMPERATURES ARE CONCERNED STILL GOING WITH A
HIGH NEAR 90 BUT SUB-VFR CEILINGS HAVE HELD ON LONGER THAN
ANTICIPATED WHICH MAY AFFECT TEMPERATURES BUT AFTER THE CEILINGS
BREAK THERE SHOULD STILL BE ENOUGH INSOLATION TO HELP TEMPERATURES
QUICKLY RECOVER. PREVIOUS DISCUSSION FOLLOWS. - ELLIS
LINGERING...WEAK SURFACE BOUNDARY REMAINS OVER CENTRAL NORTH
CAROLINA...AND IN VICINITY OF THE BOUNDARY AND THE INSTABILITY
GRADIENT NOTED ON THE SPC MESOANALYSIS...ISOLATED SHOWERS CONTINUED
EARLY THIS MORNING. THE 00Z UPPER-AIR ANALYSIS ALSO SHOWED A PARADE
OF 700MB SHORTWAVES MOVING TOWARD THE AREA IN THE NORTHWEST FLOW
ALOFT...AND THE LATEST HRRR WRF NOTES A FEW SHOWERS LINGERING
THROUGH DAWN IN CENTRAL NORTH CAROLINA. FOLLOWING THIS...THE 850MB
THETA-E RIDGE PERSISTS OVER CENTRAL NORTH CAROLINA THROUGHOUT THE
DAY IN VICINITY OF THE REMNANT BOUNDARY. ALTHOUGH JET SUPPORT IS
WELL NORTH AND NORTHWEST AND OVERALL LIFT IS FORECAST TO BE MODEST
AT BEST ON THE GFS...INSTABILITY OF AROUND 1500J/KG DURING THE
AFTERNOON SHOULD BE ENOUGH TO RESULT IN SCATTERED SHOWERS AND
THUNDERSTORMS PER A BLEND OF THE MAV AND MET MOS GUIDANCE...AND THE
CONSENSUS OF THE HIGH-RESOLUTION MODEL OUTPUT. THE CONSENSUS OF THAT
OUTPUT CERTAINLY PLACES THE HIGHER POTENTIAL FOR SCATTERED SHOWERS
AND THUNDERSTORMS IN VICINITY OF INTERSTATE 95...AND WILL SHOW THE
HIGHER CHANCES THERE FOR TODAY RELATIVE TO THE REST OF CENTRAL NORTH
CAROLINA...AGAIN CLOSER TO THE REMNANT BOUNDARY AND IN DEEPER
MOISTURE. IF THERE WAS FORECAST STRONGER LOW-LEVEL CONVERGENCE...
SHEAR...OR DIFFLUENCE ALOFT THERE MAY BE MORE CONFIDENCE IN NOTING
THE POTENTIAL FOR A LOCALLY SEVERE STORM IN THE HWO...BUT THESE
PARAMETERS ARE FORECAST TO BE SOMEWHAT WEAK ON THE GFS...THOUGH THE
0-3KM SHEAR APPROACHING 25KT IS BETTER THAN WHAT HAS BEEN NOTED IN
RECENT DAYS. WILL LIKELY NOTE THE POTENTIAL FOR A STRONG STORM IN
THE OUTLOOK...KEEPING IN MIND AN ISOLATED SEVERE STORM OR TWO CANNOT
BE COMPLETELY RULED OUT.
OVERNIGHT...A MAXIMUM OF INSTABILITY FORECAST BY THE GFS WEST OF THE
YADKIN RIVER...IN ADVANCE OF AN INCREASE IN POTENTIAL VORTICITY ON
THE 1.5 PVU SURFACE LATE THIS AFTERNOON AND THIS EVENING...MAY HELP
PROVIDE FOR SCATTERED SHOWERS AND THUNDERSTORMS MOVING INTO CENTRAL
NORTH CAROLINA FROM THE WEST...AND LINGERING INTO THE OVERNIGHT
HOURS EAST OF U.S. 1 AND INTO THE INTERSTATE 95 CORRIDOR. HIGHS
TODAY AROUND 90 MOST LOCATIONS WITH PARTLY SUNNY CONDITIONS ON
AVERAGE. OVERNIGHT LOWS TONIGHT UPPER 60S TO MID 70S NORTH TO
SOUTH.-DJF
&&
.SHORT TERM /SUNDAY AND SUNDAY NIGHT/...
AS OF 305 AM SATURDAY...
A COLD FRONT APPROACHES FROM THE NORTH AND MOVES THROUGH CENTRAL
NORTH CAROLINA DURING THE DAY SUNDAY. IN ADVANCE OF WHAT APPEARS TO
BE THE TRUE FRONT...WINDS SHOULD VEER NORTHWEST THEN BECOME MORE
TRUE NORTH OR NORTH-NORTHEAST BEHIND THE FRONT. THE 850MB FRONT
LINGERS AND IS NOT FORECAST BY THE GFS TO MOVE THROUGH CENTRAL NORTH
CAROLINA UNTIL THE EARLY AFTERNOON. THETA-E RIDGING AT 850MB SHIFTS
SOUTH ALONG WITH HIGHER VALUES OF K INDICES...AND BY AFTERNOON THE
BEST UPPER-LEVEL DIVERGENCE IS FORECAST SOUTH OF THE STATE ACROSS
SOUTH CAROLINA...WHERE THE GFS IS FAIRLY AMPLE WITH THAT PARAMETER
DURING THE AFTERNOON. BUFR SOUNDINGS SHOW INCREASING STABILITY...
ALTHOUGH THE GFS BUFR SOUNDINGS AT KFAY AND KRWI ARE CLOSER TO THE
MOIST ADIABAT IN THE TEMPERATURE PROFILE INTO SUNDAY AFTERNOON.
BESIDES THE POTENTIAL FOR AN ISOLATED SHOWER SUNDAY MORNING...IT MAY
BE DIFFICULT TO GET ANY PRECIPITATION ALONG AND NORTH OF U.S. 64
SUNDAY. CLOSER TO THE SOUTH CAROLINA BORDER...UNTIL THE 850MB FRONT
GOES THROUGH WITH ITS ASSOCIATED LIFT...AND WHILE DEW POINTS ARE
STILL AT LEAST IN THE MID 60S...AN ISOLATED-TO-SCATTERED SHOWER OR
STORM REMAINS POSSIBLE. MLCAPE IN THE LOWEST KM IS HIGHER THERE THAN
ELSEWHERE...AND DCAPE IS AT LEAST 1000J/KG IN THE FAR SOUTH
SUNDAY...WITH INCREASING SHEAR MAKING A STRONG STORM POSSIBLE THERE
IF ONE CAN DEVELOP. BY SUNSET...THIS POTENTIAL SHOULD BE LOCATED
SOUTH OF CENTRAL NORTH CAROLINA ALTOGETHER. AFTER HIGHS SUNDAY FROM
THE UPPER 80S TO LOWER 90S...OVERNIGHT LOWS IN THE DRIER AIR SHOULD
BE IN THE 60S...APPROACHING 60 ESPECIALLY NORTH OF U.S. 64.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
AS OF 255 AM SATURDAY...
HIGH PRESSURE WILL MOVE ACROSS THE MID ATLANTIC REGION ON MONDAY...
MOVING OFFSHORE BY 00Z TUE AS A MID LEVEL SHORT WAVE EMBEDDED IN THE
NW FLOW MOVES SE ACROSS THE MIDWEST. A DRY AIRMASS OVER THE STATE
EARLY MONDAY...PER FORECAST SOUNDINGS WHICH SHOW PWAT JUST BELOW ONE
INCH...WILL QUICKLY MODIFY AS THE DAY PROGRESSES AND THE HIGH MOVES
OFFSHORE. PWAT ON THESE SAME FORECAST SOUNDINGS ARE SHOWN TO
INCREASE TO AROUND 1.5 INCHES BY 03Z TUE. EVEN WITH INCREASING
MOISTURE...WILL KEEP THE FORECAST DRY ON MONDAY DUE TO VERY LIMITED
SYNOP SCALE AND LOW LEVEL FORCING.
THE AFOREMENTIONED SHORT WAVE IS PROGGED TO CROSS THE MOUNTAINS
MONDAY NIGHT AND MOVE ACROSS MID ATLANTIC AND CAROLINAS ON TUESDAY.
THE COMBINATION OF INCREASING MOISTURE AND SYNOPTIC SCALE FORCING
WITH THE SHORT WAVE WILL BRING INCREASED RAIN CHANCES TO THE AREA
LATE MONDAY NIGHT ACROSS OUR WESTERN ZONES...AND TUESDAY ACROSS ALL
OF CENTRAL NC.
DURING THE MID-WEEK PERIOD...THE WESTERLIES WILL SHIFT NORTH WITH A
WEAK RIDGE BECOMING ESTABLISHED ACROSS OUR AREA. THIS PATTERN WILL
RESULT IN A MORE TYPICAL SUMMERTIME PATTERN WITH ISOLATED TO
SCATTERED AFTERNOON/EVENING SHOWERS AND TSTMS.
BY LATE WEEK...THE NEXT SHORT WAVE AND COLD FRONT WILL APPROACH FROM
THE NW...THUS LOOK FOR INCREASING RAIN CHANCES ESP LATE ON FRIDAY.
THIS SOLUTION IS SLIGHTLY LATER IN TIMING THAN EARLIER MODEL
RUNS...WHICH BROUGHT THIS SAME SYSTEM IN AS EARLY AS LATE THURSDAY.
TEMPS DURING THE LONG TERM: A FEW DEGREES BELOW NORMAL TO START OFF
THE WEEK (LOWS IN THE MID 60S AND HIGHS IN THE MID-UPPER 80S) AS LOW
LEVEL THICKNESSES DECREASE IN THE WAKE OF THE TROUGH PASSAGE. THEN
TEMPERATURES WILL REBOUND TO NORMAL (LOWS IN THE UPPER 60S TO NEAR
70 AND HIGHS IN THE UPPER 80S TO NEAR 90) DURING THE MID-LATE WEEK
PERIOD AS THE RIDGE BUILDS OVER THE REGION.
&&
.AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...
AS OF 655 AM SATURDAY...
VFR CONDITIONS SHOULD PREVAIL DURING THE 12Z VALID TAF PERIOD...
FOLLOWING A SHORT PERIOD THROUGH MID-MORNING OF AREAS OF IFR
CONDITIONS NEAR A REMNANT SURFACE FRONT OVER CENTRAL NORTH
CAROLINA...AND IN VICINITY OF OVERNIGHT RAINFALL. SCATTERED SHOWERS
AND THUNDERSTORMS THIS AFTERNOON AND TONIGHT WOULD PRODUCE SUB-VFR
CONDITIONS BUT CURRENT POINT FORECAST PROBABILITY WAS INSUFFICIENT
TO INCLUDE IN A PREVAILING OR TEMPORARY MODE AT TAF SITES. WINDS
WILL BE SOUTHWEST PREVAILING AT 10KT OR LESS. THESE WINDS WILL BEGIN
TO VEER OVERNIGHT AS ANOTHER MORE NOTICEABLE FRONT MOVES INTO
CENTRAL NORTH CAROLINA. THERE IS A CHANCE OF LOW CLOUDS TONIGHT
TOWARD KFAY AND KRWI IN THE FRONTAL ZONE...BUT CURRENTLY THE
UNCERTAINTY WAS SUFFICIENT TO LEAVE THESE OUT OF THE TAF EXCEPT FOR
A MENTION OF FEW-SCT LOW CLOUDS AT KRWI AND KFAY LATE TONIGHT.
BEYOND THE 12Z VALID TAF PERIOD...THERE IS A CHANCE OF LATE NIGHT
LOW CLOUDS LINGERING THROUGH EARLY SUNDAY MORNING MAINLY TOWARD KRWI
AND KFAY SUNDAY BEFORE A COLD FRONT MOVES THROUGH. THIS FRONT...
MOVING THROUGH SUNDAY...WILL TURN WINDS INCREASINGLY MORE TO THE
NORTH AND BRING DRIER AIR INTO CENTRAL NORTH CAROLINA. HIGH
POTENTIAL OF VFR CONDITIONS UNDER HIGH PRESSURE OVERNIGHT SUNDAY
INTO MONDAY...THEN MOISTURE INCREASES ONCE AGAIN BY TUESDAY...
RENEWING CHANCES OF SHOWERS AND THUNDERSTORMS FOR THE MIDDLE OF THE
WEEK. CHANCES OF LATE NIGHT AND EARLY MORNING LOW CLOUDS INCREASE AS
WELL...WITH THE CURRENT GUIDANCE HIGHER WITH THESE TOWARD THE TRIAD
WEDNESDAY MORNING.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...DJF
NEAR TERM...ELLIS/DJF
SHORT TERM...DJF
LONG TERM...NP
AVIATION...DJF
AREA FORECAST DISCUSSION
NWS RALEIGH NC
655 AM EDT SAT AUG 3 2013
.SYNOPSIS...
AS A WEAK FRONT LIES OVER THE AREA...ANOTHER...STRONGER COLD FRONT
APPROACHES FROM THE NORTHWEST. THIS FRONT WILL PASS THROUGH THE
REGION SUNDAY. HIGH PRESSURE BUILDS IN BEHIND THE FRONT MONDAY
BEFORE MOVING OFF THE MID-ATLANTIC COAST TUESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 305 AM SATURDAY...
LINGERING...WEAK SURFACE BOUNDARY REMAINS OVER CENTRAL NORTH
CAROLINA...AND IN VICINITY OF THE BOUNDARY AND THE INSTABILITY
GRADIENT NOTED ON THE SPC MESOANALYSIS...ISOLATED SHOWERS CONTINUED
EARLY THIS MORNING. THE 00Z UPPER-AIR ANALYSIS ALSO SHOWED A PARADE
OF 700MB SHORTWAVES MOVING TOWARD THE AREA IN THE NORTHWEST FLOW
ALOFT...AND THE LATEST HRRR WRF NOTES A FEW SHOWERS LINGERING
THROUGH DAWN IN CENTRAL NORTH CAROLINA. FOLLOWING THIS...THE 850MB
THETA-E RIDGE PERSISTS OVER CENTRAL NORTH CAROLINA THROUGHOUT THE
DAY IN VICINITY OF THE REMNANT BOUNDARY. ALTHOUGH JET SUPPORT IS
WELL NORTH AND NORTHWEST AND OVERALL LIFT IS FORECAST TO BE MODEST
AT BEST ON THE GFS...INSTABILITY OF AROUND 1500J/KG DURING THE
AFTERNOON SHOULD BE ENOUGH TO RESULT IN SCATTERED SHOWERS AND
THUNDERSTORMS PER A BLEND OF THE MAV AND MET MOS GUIDANCE...AND THE
CONSENSUS OF THE HIGH-RESOLUTION MODEL OUTPUT. THE CONSENSUS OF THAT
OUTPUT CERTAINLY PLACES THE HIGHER POTENTIAL FOR SCATTERED SHOWERS
AND THUNDERSTORMS IN VICINITY OF INTERSTATE 95...AND WILL SHOW THE
HIGHER CHANCES THERE FOR TODAY RELATIVE TO THE REST OF CENTRAL NORTH
CAROLINA...AGAIN CLOSER TO THE REMNANT BOUNDARY AND IN DEEPER
MOISTURE. IF THERE WAS FORECAST STRONGER LOW-LEVEL CONVERGENCE...
SHEAR...OR DIFFLUENCE ALOFT THERE MAY BE MORE CONFIDENCE IN NOTING
THE POTENTIAL FOR A LOCALLY SEVERE STORM IN THE HWO...BUT THESE
PARAMETERS ARE FORECAST TO BE SOMEWHAT WEAK ON THE GFS...THOUGH THE
0-3KM SHEAR APPROACHING 25KT IS BETTER THAN WHAT HAS BEEN NOTED IN
RECENT DAYS. WILL LIKELY NOTE THE POTENTIAL FOR A STRONG STORM IN
THE OUTLOOK...KEEPING IN MIND AN ISOLATED SEVERE STORM OR TWO CANNOT
BE COMPLETELY RULED OUT.
OVERNIGHT...A MAXIMUM OF INSTABILITY FORECAST BY THE GFS WEST OF THE
YADKIN RIVER...IN ADVANCE OF AN INCREASE IN POTENTIAL VORTICITY ON
THE 1.5 PVU SURFACE LATE THIS AFTERNOON AND THIS EVENING...MAY HELP
PROVIDE FOR SCATTERED SHOWERS AND THUNDERSTORMS MOVING INTO CENTRAL
NORTH CAROLINA FROM THE WEST...AND LINGERING INTO THE OVERNIGHT
HOURS EAST OF U.S. 1 AND INTO THE INTERSTATE 95 CORRIDOR. HIGHS
TODAY AROUND 90 MOST LOCATIONS WITH PARTLY SUNNY CONDITIONS ON
AVERAGE. OVERNIGHT LOWS TONIGHT UPPER 60S TO MID 70S NORTH TO SOUTH.
&&
.SHORT TERM /SUNDAY AND SUNDAY NIGHT/...
AS OF 305 AM SATURDAY...
A COLD FRONT APPROACHES FROM THE NORTH AND MOVES THROUGH CENTRAL
NORTH CAROLINA DURING THE DAY SUNDAY. IN ADVANCE OF WHAT APPEARS TO
BE THE TRUE FRONT...WINDS SHOULD VEER NORTHWEST THEN BECOME MORE
TRUE NORTH OR NORTH-NORTHEAST BEHIND THE FRONT. THE 850MB FRONT
LINGERS AND IS NOT FORECAST BY THE GFS TO MOVE THROUGH CENTRAL NORTH
CAROLINA UNTIL THE EARLY AFTERNOON. THETA-E RIDGING AT 850MB SHIFTS
SOUTH ALONG WITH HIGHER VALUES OF K INDICES...AND BY AFTERNOON THE
BEST UPPER-LEVEL DIVERGENCE IS FORECAST SOUTH OF THE STATE ACROSS
SOUTH CAROLINA...WHERE THE GFS IS FAIRLY AMPLE WITH THAT PARAMETER
DURING THE AFTERNOON. BUFR SOUNDINGS SHOW INCREASING STABILITY...
ALTHOUGH THE GFS BUFR SOUNDINGS AT KFAY AND KRWI ARE CLOSER TO THE
MOIST ADIABAT IN THE TEMPERATURE PROFILE INTO SUNDAY AFTERNOON.
BESIDES THE POTENTIAL FOR AN ISOLATED SHOWER SUNDAY MORNING...IT MAY
BE DIFFICULT TO GET ANY PRECIPITATION ALONG AND NORTH OF U.S. 64
SUNDAY. CLOSER TO THE SOUTH CAROLINA BORDER...UNTIL THE 850MB FRONT
GOES THROUGH WITH ITS ASSOCIATED LIFT...AND WHILE DEW POINTS ARE
STILL AT LEAST IN THE MID 60S...AN ISOLATED-TO-SCATTERED SHOWER OR
STORM REMAINS POSSIBLE. MLCAPE IN THE LOWEST KM IS HIGHER THERE THAN
ELSEWHERE...AND DCAPE IS AT LEAST 1000J/KG IN THE FAR SOUTH
SUNDAY...WITH INCREASING SHEAR MAKING A STRONG STORM POSSIBLE THERE
IF ONE CAN DEVELOP. BY SUNSET...THIS POTENTIAL SHOULD BE LOCATED
SOUTH OF CENTRAL NORTH CAROLINA ALTOGETHER. AFTER HIGHS SUNDAY FROM
THE UPPER 80S TO LOWER 90S...OVERNIGHT LOWS IN THE DRIER AIR SHOULD
BE IN THE 60S...APPROACHING 60 ESPECIALLY NORTH OF U.S. 64.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
AS OF 255 AM SATURDAY...
HIGH PRESSURE WILL MOVE ACROSS THE MID ATLANTIC REGION ON MONDAY...
MOVING OFFSHORE BY 00Z TUE AS A MID LEVEL SHORT WAVE EMBEDDED IN THE
NW FLOW MOVES SE ACROSS THE MIDWEST. A DRY AIRMASS OVER THE STATE
EARLY MONDAY...PER FORECAST SOUNDINGS WHICH SHOW PWAT JUST BELOW ONE
INCH...WILL QUICKLY MODIFY AS THE DAY PROGRESSES AND THE HIGH MOVES
OFFSHORE. PWAT ON THESE SAME FORECAST SOUNDINGS ARE SHOWN TO
INCREASE TO AROUND 1.5 INCHES BY 03Z TUE. EVEN WITH INCREASING
MOISTURE...WILL KEEP THE FORECAST DRY ON MONDAY DUE TO VERY LIMITED
SYNOP SCALE AND LOW LEVEL FORCING.
THE AFOREMENTIONED SHORT WAVE IS PROGGED TO CROSS THE MOUNTAINS
MONDAY NIGHT AND MOVE ACROSS MID ATLANTIC AND CAROLINAS ON TUESDAY.
THE COMBINATION OF INCREASING MOISTURE AND SYNOPTIC SCALE FORCING
WITH THE SHORT WAVE WILL BRING INCREASED RAIN CHANCES TO THE AREA
LATE MONDAY NIGHT ACROSS OUR WESTERN ZONES...AND TUESDAY ACROSS ALL
OF CENTRAL NC.
DURING THE MID-WEEK PERIOD...THE WESTERLIES WILL SHIFT NORTH WITH A
WEAK RIDGE BECOMING ESTABLISHED ACROSS OUR AREA. THIS PATTERN WILL
RESULT IN A MORE TYPICAL SUMMERTIME PATTERN WITH ISOLATED TO
SCATTERED AFTERNOON/EVENING SHOWERS AND TSTMS.
BY LATE WEEK...THE NEXT SHORT WAVE AND COLD FRONT WILL APPROACH FROM
THE NW...THUS LOOK FOR INCREASING RAIN CHANCES ESP LATE ON FRIDAY.
THIS SOLUTION IS SLIGHTLY LATER IN TIMING THAN EARLIER MODEL
RUNS...WHICH BROUGHT THIS SAME SYSTEM IN AS EARLY AS LATE THURSDAY.
TEMPS DURING THE LONG TERM: A FEW DEGREES BELOW NORMAL TO START OFF
THE WEEK (LOWS IN THE MID 60S AND HIGHS IN THE MID-UPPER 80S) AS LOW
LEVEL THICKNESSES DECREASE IN THE WAKE OF THE TROUGH PASSAGE. THEN
TEMPERATURES WILL REBOUND TO NORMAL (LOWS IN THE UPPER 60S TO NEAR
70 AND HIGHS IN THE UPPER 80S TO NEAR 90) DURING THE MID-LATE WEEK
PERIOD AS THE RIDGE BUILDS OVER THE REGION.
&&
.AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...
AS OF 655 AM SATURDAY...
VFR CONDITIONS SHOULD PREVAIL DURING THE 12Z VALID TAF PERIOD...
FOLLOWING A SHORT PERIOD THROUGH MID-MORNING OF AREAS OF IFR
CONDITIONS NEAR A REMNANT SURFACE FRONT OVER CENTRAL NORTH
CAROLINA...AND IN VICINITY OF OVERNIGHT RAINFALL. SCATTERED SHOWERS
AND THUNDERSTORMS THIS AFTERNOON AND TONIGHT WOULD PRODUCE SUB-VFR
CONDITIONS BUT CURRENT POINT FORECAST PROBABILITY WAS INSUFFICIENT
TO INCLUDE IN A PREVAILING OR TEMPORARY MODE AT TAF SITES. WINDS
WILL BE SOUTHWEST PREVAILING AT 10KT OR LESS. THESE WINDS WILL BEGIN
TO VEER OVERNIGHT AS ANOTHER MORE NOTICEABLE FRONT MOVES INTO
CENTRAL NORTH CAROLINA. THERE IS A CHANCE OF LOW CLOUDS TONIGHT
TOWARD KFAY AND KRWI IN THE FRONTAL ZONE...BUT CURRENTLY THE
UNCERTAINTY WAS SUFFICIENT TO LEAVE THESE OUT OF THE TAF EXCEPT FOR
A MENTION OF FEW-SCT LOW CLOUDS AT KRWI AND KFAY LATE TONIGHT.
BEYOND THE 12Z VALID TAF PERIOD...THERE IS A CHANCE OF LATE NIGHT
LOW CLOUDS LINGERING THROUGH EARLY SUNDAY MORNING MAINLY TOWARD KRWI
AND KFAY SUNDAY BEFORE A COLD FRONT MOVES THROUGH. THIS FRONT...
MOVING THROUGH SUNDAY...WILL TURN WINDS INCREASINGLY MORE TO THE
NORTH AND BRING DRIER AIR INTO CENTRAL NORTH CAROLINA. HIGH
POTENTIAL OF VFR CONDITIONS UNDER HIGH PRESSURE OVERNIGHT SUNDAY
INTO MONDAY...THEN MOISTURE INCREASES ONCE AGAIN BY TUESDAY...
RENEWING CHANCES OF SHOWERS AND THUNDERSTORMS FOR THE MIDDLE OF THE
WEEK. CHANCES OF LATE NIGHT AND EARLY MORNING LOW CLOUDS INCREASE AS
WELL...WITH THE CURRENT GUIDANCE HIGHER WITH THESE TOWARD THE TRIAD
WEDNESDAY MORNING.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...DJF
NEAR TERM...DJF
SHORT TERM...DJF
LONG TERM...NP
AVIATION...DJF
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
1010 AM CDT SAT AUG 3 2013
.UPDATE...
ISSUED AT 1008 AM CDT SAT AUG 3 2013
STRATIFORM AREA TO NORTH OF NEBRASKA CONVECTION AGAIN CAUSING
ISSUES WITH THE ONGOING FORECAST. MADE AN EARLIER UPDATE FOR
WIDESPREAD LIGHT PRECIP IN THE SOUTHWEST CWA EARLY THIS MORNING...
AND NOW CONSIDERING MORE OF THE LONGER RANGE IMPACTS IN SKYCOVER
AND TEMPS. WITH PARENT CONVECTION NOW UNDERGOING A WEAKENING
CYCLE...WOULD EXPECT THAT STRATIFORM AREA WOULD ALSO START TO
DIMINISH STARTING IN THE NEXT HOUR OR TWO...AND HAVE TRIED TO DRAW
THIS INTO THE HOURLY GRIDS. ALSO COMPLICATING IS THE DRIER AIRMASS
AT LOW LEVELS TO THE EAST...ALL OF WHICH WILL BE ERODING ADVANCING
PRECIP. HRRR HAS THE GENERAL IDEA...BUT FAR TOO EXTENSIVE. SHOULD
GET PRETTY RAGGED BY THE TIME IT STRETCHES INTO NORTHEAST NEBRASKA
BY VERY LATE MORNING...AND MUCH MORE LIKELY TO NOT MAKE IT TO KSUX
WITH ALL ELEMENTS WORKING AGAINST THE AGGRESSIVE EASTWARD PUSH.
ALSO...NOT VERY ENTHUSIASTIC ABOUT MENTION OF THUNDER WITH
ACTIVITY. MUCH MORE LIKELY TO GET AN ISOLATED STORM DEVELOPING
AFTER INITIAL STRATIFORM AREA SLIDES PAST ON THE BACK SIDE ACROSS
THE LOWER BRULE AREA...ABOUT THE ONLY LOCATION TO EXHIBIT ANY
ELEVATED INSTABILITY.
PUSHED BACK DIURNAL RISE QUITE A BIT UNDER THICK CLOUD SHIELD THIS
MORNING...AND KNOCKED BACK HIGHS ALREADY A COUPLE DEGREES IN THE
SOUTHWEST LOCATION...BUT SOMEWHAT CAUTIOUS TO DO MUCH MORE GIVEN
LIKELIHOOD OF LATER DAY PARTIAL CLEARING. PLAN TO SLOW UP THE
RISES A BIT MORE...AND SHAVE PERHAPS ANOTHER DEGREE OR TWO OFF ON
DAYTIME EXPECTATIONS FOR MORE CLOUDY LOCATIONS.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 351 AM CDT SAT AUG 3 2013
CONVECTION FIRING EARLY THIS MORNING ACROSS WESTERN SOUTH DAKOTA ON
THE NOSE OF AN INCREASING LOW LEVEL JET. EXPECT THIS AREA OF STORMS
TO EXPAND SOME THIS MORNING...WITH A SOUTHEAST STORM MOTION.
ELEVATED INSTABILITY REALLY DROPS OFF AS YOU HEAD EAST TOWARDS OUR
CWA. THUS EXPECT ANY STRONGER ACTIVITY TO STAY SOUTH AND WEST INTO
NEBRASKA. HOWEVER COULD SEE SOME LIGHTER RAIN OR POSSIBLY A
THUNDERSTORM ON THE NORTHERN EDGE OF THE COMPLEX MAKE IT INTO THE
SOUTHWEST PORTION OF THE CWA...TOWARDS GREGORY AND CHARLES MIX
COUNTIES...THIS MORNING. OTHERWISE EXPECTING PARTLY TO MOSTLY SUNNY
SKIES OVER THE AREA...WITH INCREASING SUN THE FURTHER NORTHEAST YOU
GET. THINK WE SEE ENOUGH SUN TO REACH NEAR FULL MIXING POTENTIAL
TODAY...HOWEVER THAT WILL STILL LEAVE US SEVERAL DEGREES BELOW
NORMAL..WITH MID AND UPPER 70S COMMON. TONIGHT WILL LIKELY START
MOSTLY CLEAR...WITH INCREASING CLOUDS FROM WEST TO EAST. IT AGAIN
APPEARS LIKELY THAT CONVECTION WILL GET GOING ON THE THE LOW LEVEL
JET WEST OF OUR AREA DURING THE FIRST PART OF THE NIGHT. LOOKS LIKE
A STRONGER WAVE ACCOMPANYING THIS CONVECTION...AND BETTER ANTECEDENT
MOISTURE OVERHEAD. THUS LOOKS LIKE A BETTER CHANCE THAT THIS
THUNDERSTORM ACTIVITY MAKES IT INTO OUR CWA. ALTHOUGH AGAIN ELEVATED
INSTABILITY IS PRETTY MINIMAL...THUS WOULD NOT EXPECT TO SEE ANY
SEVERE WEATHER. TIMING SEEMS TO PUT THE CONVECTION ENTERING OUR
WESTERN CWA A FEW HOURS EITHER SIDE OF 12Z. LOWS WILL RANGE FROM THE
MID 50S EAST WHERE CLOUDS WILL BE LAST TO ARRIVE...TO AROUND 60
WEST.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 351 AM CDT SAT AUG 3 2013
FOR THE DAY ON SUNDAY...ANTICIPATE AFOREMENTIONED CONVECTION TO
SPREAD INTO THE WESTERN PORTIONS OF THE CWA THROUGH THE EARLY PART
OF THE DAY PER LOW LEVEL FORCING VIA THE 850 MB JET...WITH HIGHER
POPS ACROSS OUR NORTHWEST CLOSER TO THE BETTER LIFT SUPPORTED BY MODEL
DIV Q FIELDS. THINK THERE WILL BE A GENERALLY DOWNWARD TREND IN
CONVECTION THROUGH THE DAY AS LOW LEVEL FORCING WEAKENS. ALTHOUGH
850 MB TEMPERATURES WARM A TAD ON SUNDAY...THINK THAT CLOUD
COVER/ASSOCIATED SHOWERS WILL KEEP READINGS DOWN ACROSS THE NORTHERN
TWO THIRDS OF THE CWA...WITH HIGHS TOPPING OUT IN THE LOWER TO MID
70S OVER THAT AREA...TO NEAR 80 THROUGH THE LOWER MISSOURI RIVER
VALLEY.
ON SUNDAY NIGHT THINK THE BETTER CHANCE OF CONVECTION WILL EXIST
OVER OUR NORTHEASTERN AREAS AS A SECONDARY SHORTWAVE DROPS THROUGH
NORTHEASTERN SOUTH DAKOTA INTO SOUTHERN MINNESOTA OVERNIGHT. IT WILL
BE A LITTLE MILDER ON SUNDAY NIGHT IN THE RETURN SOUTHERLY FLOW ON
THE BACKSIDE OF AN EXITING SURFACE RIDGE...WITH LOWS GENERALLY IN
THE LOWER 60S.
WITH SUBSIDENCE BEHIND THE EXITING WAVE...EXPECT A LESSER CHANCE OF
CONVECTION DURING THE DAY ON MONDAY. TEMPERATURES WILL CLIMB A BIT
IN CONTINUED WARMING THERMAL PROFILES AND MORE SUN...WITH HIGHS INTO
THE UPPER 70S TO MID 80S. CONVECTION EXPECTED TO DEVELOP OVER
WESTERN SOUTH DAKOTA ON MONDAY NIGHT COULD PUSH INTO OUR WESTERN
AREAS LATE...THOUGH MODELS OF COURSE DIFFERING ON HOW THIS SCENARIO
EVOLVES. AN EVEN MILDER NIGHT EXPECTED WITH LOWS IN THE LOWER TO MID
60S.
FARTHER INTO THE EXTENDED...MODELS IN FAIRLY DECENT AGREEMENT ON
BRINGING A COLD FRONT THROUGH THE REGION LATER ON TUESDAY...WITH
ADDITIONAL CONVECTION POSSIBLE. DEPENDING ON TIMING...CONVECTIVE
PARAMETERS WOULD SUGGEST THAT SEVERE STORMS WOULD BE POSSIBLE ON
TUESDAY AFTERNOON AND EVENING. AFTER THAT...MODELS IN AGREEMENT ON
OUR AREA BEING IN A NORTHWESTERLY UPPER LEVEL FLOW THROUGH THE
REMAINDER OF THE WEEK AS A BROAD UPPER LEVEL LOW SPINS OVER EASTERN
CANADA/NORTHERN GREAT LAKES REGION. THIS WILL KEEP BELOW NORMAL
TEMPERATURES LOCKED OVER OUR AREA...WITH HIGHS GENERALLY IN THE 70S
AND LOWS IN THE 50S. WITH OBVIOUS MODEL DIFFERENCES THAT FAR
OUT...STUCK WITH CONSENSUS IN TERMS OF PRECIPITATION THROUGH THE
PERIOD...WITH ONLY LOW CHANCES FOR THE END OF NEXT WEEK.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 617 AM CDT SAT AUG 3 2013
SOME PATCHY MORNING FOG WILL QUICKLY BURN OFF WITH SUNRISE. A FEW
SHOWERS AND MAYBE A THUNDERSTORM WILL CLIP SOUTH CENTRAL SOUTH DAKOTA
THIS MORNING...BUT ALL TAF SITES SHOULD REMAIN IN THE CLEAR. VFR
CONDITIONS WILL THUS DOMINATE THROUGH THE DAY INTO THE FIRST PART OF
TONIGHT. ANOTHER AREA OF CONVECTION MAY APPROACH HURON FROM THE WEST
TOWARDS 12Z. DID ADD IN A TEMPO SHOWER GROUP. INSTABILITY IS LOW BUT
COULD VERY WELL BE THUNDER WITH ANYTHING THAT MOVES IN...BUT HELD OFF
ON MENTIONING UNTIL CONFIDENCE OF COVERAGE AND TIMING INCREASES.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
UPDATE...CHAPMAN
SHORT TERM...CHENARD
LONG TERM...JM
AVIATION...CHENARD
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
957 AM EDT SAT AUG 3 2013
.SYNOPSIS...
A COLD FRONT WILL MOVE SOUTHEAST THROUGH THE AREA LATE TODAY INTO
TONIGHT...PRECEDED AND ACCOMPANIED BY SHOWERS AND THUNDERSTORMS.
HIGH PRESSURE FOLLOWING THE FRONT WILL BRING DRIER AND COOLER AIR
BACK INTO THE REGION SUNDAY INTO MONDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 950 AM EDT SATURDAY...
KFCX 88D LOOP SHOWED SCATTERED SHOWERS TRAVELING EAST ACROSS
CWA THIS MORNING ASSOCIATED WITH ISENTROPIC LIFT. EXPANDED THE LIGHT
POPS TO THE EAST THIS MORNING...AS THEY BATTLE THE DOWNSLOPE FLOW.
RNK WRF ARW SHOWED SHOWERS WEAKENING WITH PROGRESSION EASTWARD.
THIS MORNING 8AM/12Z RNK SOUNDING INDICATED THAT PWATS HAVE
INCREASED TO 1.20 INCH WITH A WEST FLOW.
SHORTWAVE TROF WILL DROP SOUTHEAST TODAY INTO TONIGHT. A COOL FRONT
WILL MOVE INTO AND THROUGH THE BLACKSBURG FORECAST AREA TONIGHT. A
COUPLE OF WEAK BOUNDARIES AHEAD OF THE FRONT MAY COMBINE WITH
LIMITED INSTABILITY TO CREATE WIDELY SCATTERED TO SCATTERED SHOWERS
AND THUNDERSTORMS THIS AFTERNOON INTO THIS EVENING HELP BY CONFLUENCE
ZONE.
NAM AND WRF INDICATED THAT BEST INSTABILITY REMAINS LOCKED UP OVER
SOUTHSIDE VIRGINIA INTO NORTH CENTRAL NORTH CAROLINA WHERE MUCH
DEEPER LOW LEVEL MOISTURE RESIDES IN VICINITY OF OLD FRONT. IF
CLOUD COVER THINS ENOUGH...SCATTERED SHOWERS AND THUNDERSTORMS
COULD DEVELOP BY LATE AFTERNOON IN SOUTHEASTERN PART OF FORECAST
AREA. A STRONGER THUNDERSTORM COULD CONTAIN GUSTY WINDS AND
HEAVY DOWNPOURS.
SHOWERS AND THUNDERSTORMS THIS EVENING INTO TONIGHT WILL DIMINISH
WITH THE LOSS OF SOLAR HEATING AS SHORTWAVE ENERGY REMAINS WELL
NORTH OF US. MADE SOME MINOR ADJUSTMENTS TO POPS...TEMPERATURES
AND CLOUD COVER IN ISC GRIDS.
AS OF 355 AM EDT SATURDAY...
SCATTERED SHOWERS CURRENTLY MOVING EAST OUT OF EASTERN KY AND WV
ON NOSE OF ISENTROPIC LIFT ZONE MAXIMIZED IN 850-700 MILLIBAR
LAYER...AND WILL LIKELY CONTINUE EAST INTO NORTHWESTERN PORTION OF
THE BLACKSBURG FORECAST AREA THROUGH THE DAYBREAK HOURS BEFORE
DISSIPATING EAST OF THE BLUE RIDGE BY MID MORNING AS AREA
ENCOUNTERS INCREASINGLY DOWNSLOPE FLOW. OTHERWISE...EXPECT TO SEE
ANY EARLY MORNING FOG IN MOUNTAIN VALLEYS...AND ACROSS SOUTHSIDE
VA INTO NORTH CENTRAL NC IN VICINITY OF OLD FRONTAL BOUNDARY
RAPIDLY DISSIPATE WITH ONSET OF DAYTIME HEATING.
TRICKY FORECAST FOR REST OF TODAY AS A COMBINATION OF WEATHER
FEATURES COMPETE FOR ATTENTION. WIDESPREAD AREA OF SHOWERS
CURRENTLY OVER OH VALLEY ASSOCIATED WITH FIRST IN SERIES OF SHORT
WAVE TROFS THAT WILL PROGRESSIVELY CARVE OUT UPPER TROF OVER THE
NORTHEASTERN PORTION OF THE NATION THIS WEEKEND...DRIVING COOL
FRONT INTO AND THROUGH THE BLACKSBURG FORECAST AREA TONIGHT. LOCAL
WRF AND HRRR MODELS INDICATING THAT PRECEDING AREA OF SHOWERS MAY
HELP GENERATE AND PUSH OUTFLOW BOUNDARY SOUTHEAST OUT AHEAD OF
THE FRONT INTO NORTHERN THIRD OF THE BLACKSBURG FORECAST AREA THIS
AFTERNOON. DESPITE RATHER LACKLUSTER MID LEVEL INSTABILITY...AND
POTENTIAL OF AT LEAST SOME OFFSET OF INSOLATIVE POTENTIAL DUE TO
LINGERING MID AND HIGH LEVEL CLOUDS...WIDELY SCATTERED TO
SCATTERED SHOWERS/THUNDERSTORMS ARE EXPECTED TO DEVELOP BY/DURING
THE EARLY TO MID AFTERNOON IN ASSOCIATED CONFLUENCE ZONE...
ESPECIALLY NORTH OF HIGHWAY 460...AND ACROSS WESTERN FLANKS OF THE
APPALACHIANS AS WESTERLY UPSLOPING WINDS PROVIDE SOME NEEDED
UPWARD ASSIST.
MUCH BETTER INSTABILITY REMAINS LOCKED UP OVER SOUTHSIDE VA INTO
NORTH CENTRAL NC WHERE MUCH DEEPER LOW LEVEL/TROPICAL MOISTURE
RESIDES IN VICINITY OF OLD FRONT. SHORT RANGE AND MESOSCALE
MODELS HIGHLIGHT THIS AREA FOR ADDITIONAL SCATTERED
SHOWER/THUNDERSTORM DEVELOPMENT...ALTHOUGH ANY NORTHWARD PUSH OF
THIS AIRMASS INTO VA APPEARS UNLIKELY CONSIDERING SLOW VEERING OF
WINDS AS ZONAL FLOW INCREASES OVER AREA.
IN LIGHT OF THE ABOVE...BEST THREAT FOR WIDELY SCATTERED TO
SCATTERED SHOWERS/THUNDERSTORMS TODAY WILL BE ACROSS THE
NORTH...NORTHWEST...AND SOUTHEAST PORTION OF THE BLACKSBURG
FORECAST AREA...WITH RELATIVE MINIMUM (MORE ISOLATED) THREAT FROM
THE FOOTHILLS OF NORTHWEST NC NORTHEAST TOWARD FARMVILLE VA.
SEVERE WEATHER THREAT AT THE PRESENT TIME APPEARS TO BE REMOTE.
LOSS OF DAYTIME HEATING AND LITTLE TO NO DYNAMIC SUPPORT AS SHORT
WAVE ENERGY REMAINS WELL NORTH OF THE BLACKSBURG AREA SHOULD
SUPPORT DEMISE OF LINGERING SHOWER/THUNDERSTORM ACTIVITY IN MOST
AREAS BEFORE MIDNIGHT TONIGHT...BUT WITH A LOW THREAT OF SOME
STRAY SHOWERS REMAINING INTO THE EARLY MORNING HOURS ACROSS THE
SOUTHWESTERN MOUNTAINS WHERE A BIT DEEPER MOISTURE PROFILE WILL
RESIDE AS COLDER AIR FOLDS INTO AREA FROM THE NORTH.
MOS GUIDANCE GENERALLY ACCEPTED FOR THE NEAR TERM PERIOD...WITH
HIGHS TODAY IN THE 70S ACROSS THE HIGHER TERRAIN TO 80S
ELSEWHERE...WITH OVERNIGHT LOWS MAINLY IN THE 60S EXCLUDING SOME
MID TO UPPER 50S IN SOME OF THE DEEPER MOUNTAIN VALLEYS.
&&
.SHORT TERM /SUNDAY THROUGH TUESDAY NIGHT/...
AS OF 430 AM EDT SATURDAY...
A BRIEF AMPLIFICATION OF THE NW FLOW ALOFT WILL ALLOW A FAIRLY
SUBSTANTIAL AREA OF COOL...DRY HIGH PRESSURE TO SPREAD SE ACROSS
THE REGION BEHIND A COLD FRONT WHICH WILL PUSH INTO SOUTH CAROLINA
BEFORE STALLING MONDAY. THIS WILL PROVIDE THE FORECAST AREA WITH
A RESPITE FROM THE INCESSANT SHRA/TSRA ACTIVITY OF RECENT DAYS AND
ALLOW A QUITE DRY AIR MASS TO SPREAD THROUGH THE AREA BY EARLY
MON. ANY REMNANT -SHRA AROUND DAYBREAK SUN...SHOULD DISSIPATE
QUICKLY AND SKIES SHOULD CLEAR EAST OF THE ALLEGHANYS. CANNOT RULE
OUT LINGERING UPSLOPE SC ACROSS SE WV...BUT OVERALL EVEN THOSE
AREAS SHOULD CLEAR OUT BY EVENING.
TEMPS SUN SHOULD BE BELOW NORMAL WEST OF THE ALLEGHANYS...BUT
NEAR NORMAL ACROSS THE PIEDMONT FROM STRONG INSOLATION AND
DOWNSLOPE NW FLOW. MON MORNING SHOULD BE THE COOLEST MORNING OF
THE NEXT SEVEN DAYS AND RIVAL THE RECENT PAST COUPLE OF COOL
SPELLS WHERE MIN TEMPS DIPPED INTO THE UPPER 40S IN DEEPER
MOUNTAIN VALLEYS WITH WIDESPREAD 50S WEST OF THE BLUE
RIDGE...LOWER 60S ACROSS THE PIEDMONT.
FOR TUE...THE FIRST IN A LONG SERIES OF NW FLOW DISTURBANCES
TRACKS ACROSS THE REGION AS A PRONOUNCED BAROCLINIC ZONE BEGINS TO
SET UP ACROSS THE REGION FROM NW-SE FROM THE OHIO VALLEY TOWARD
THE MID-ATLANTIC...BEGINNING WHAT SHOULD BE A 3-5 DAY PERIOD OF
QUITE ACTIVE CONVECTIVE WEATHER. FOR TUE...SFC MOISTURE WILL JUST
BE RECOVERING...SO NOT EXPECTING AN OVERLY ACTIVE CONVECTIVE DAY
JUST YET. THE MON SFC HIGH WILL MOVE TO A POSITION OFF THE MID-
ATLANTIC COAST AND ALLOW A WEAK WEDGE SITUATION TO EVOLVE EAST OF
THE BLUE RIDGE. FOR NOW...HAVE ADVERTISED LOW CHC POPS MOST
AREAS...BUT THE BEST THREAT FOR PCPN APPEARS TO BE EAST OF OR NEAR
THE ALLEGHANYS AT THIS TIME WHERE LOW-LEVEL MOISTURE CONVERGENCE
AND SFC TD IS MAXIMIZED AND DIFFERENTIAL HEATING MAY HELP SPARK
INITIAL CONVECTION DURING THE AFTERNOON. MAX/MIN TEMPS WILL BEGIN
TO RECOVER FROM THE MON COOL SPELL AND SHOULD BE CLOSER TO
NORMAL...EXCEPT STILL SLIGHTLY BELOW NORMAL IN THE FAR N-NW PART
OF THE CWA.
&&
.LONG TERM /WEDNESDAY THROUGH FRIDAY/...
AS OF 445 AM EDT SATURDAY...
AS NOTED THE PAST SEVERAL DAYS...THIS PERIOD LOOKS TO BE QUITE
ACTIVE WITH REGARD TO CONVECTION. THE FLOW WILL TREND TOWARD AN
INCREASINGLY ZONAL FLOW WITH A SERIES OF EMBEDDED DISTURBANCES
ALOFT. A WEAK COLD FRONT WILL BEGIN TO ENTER THE NW PART OF THE
CWA BY THU...THEN ATTEMPT TO PUSH SLOWLY SOUTHEASTWARD THU-FRI.
HOW FAR S-SE THE FRONT MOVES BEFORE STALLING IS HIGHLY
QUESTIONABLE GIVEN THE INCREASING ZONAL FLOW IN PLACE AND A
SUBTROPICAL RIDGE BUILDING ACROSS THE SE STATES. BOTH THE GFS AND
ECMWF TRY TO PUSH THE FRONT COMPLETELY SOUTH OF OUR CWA BY
SATURDAY AS IT STRENGTHENS THE NW FLOW JUST ENOUGH TO DO SO...BUT
AS NOTED...THAT IS SOMEWHAT DOUBTFUL.
AT ANY RATE...WED-THU LOOK QUITE ACTIVE AND
PROBLEMATIC...ESPECIALLY IN TERMS OF FLASH FLOOD POTENTIAL. PWATS
REACH OR EXCEED 2.0 INCHES ACROSS MUCH OF THE CWA WED- THU
AFTERNOON. THIS COMBINED WITH PERIODIC AMPLE UPPER SUPPORT FROM
EMBEDDED SHORT WAVES AND THE VERY WET ANTECEDENT CONDITIONS WILL
HAVE TO BE WATCHED VERY CAREFULLY. WITH A NEARLY STALLED OR QUASI-
STATIONARY FRONTAL BOUNDARY DRAPED ACROSS THE REGION AND FAVORABLE
SUPPORT...TRAINING OF SHRA/TSRA ACTIVITY APPEARS LIKELY.
FURTHERMORE...INSTABILITY LOOKS QUITE HEALTHY WITH CAPES REACHING
2000 J/KG OR GREATER WED AND THU AFTERNOON ACROSS MUCH OF THE CWA.
THUS...A FEW STRONG TO SEVERE THUNDERSTORMS ALSO APPEAR LIKELY.
HAVE INTRODUCED THE MENTION OF HEAVY RAIN TO THE ZFP FOR THESE
PERIODS AND WILL ALSO CONTINUE TO INCLUDE THE THREAT OF HEAVY RAIN
AND ISOLATED SEVERE IN THE HWO.
HUMIDITY LEVELS WILL BE QUITE HIGH THROUGH THE EXTENDED
PERIODS...SO THERE WILL BE LITTLE COOLING AT NIGHT. BY THE SAME
TOKEN...MAX TEMPS SHOULD REMAIN NEAR NORMAL...PERHAPS SLIGHTLY BELOW
IN AREAS THAT HAVE ENOUGH CLOUD COVER/PCPN TO LIMIT HEATING.
NONETHELESS...IT WILL BE QUITE MUGGY AND MUCH MORE UNCOMFORTABLE
THAN THE BEGINNING OF THE WEEK.
&&
.AVIATION /14Z SATURDAY THROUGH WEDNESDAY/...
AS OF 730 AM EDT SATURDAY...
FIRST BAND OF -SHRA ASSOCIATED WITH UPSTREAM TROUGH/FRONTAL SYSTEM
HAS ALREADY PASSED THROUGH THE CWA. ONLY BLF REPORTED -RA AND A
TRACE OF PCPN...AS EXPECTED MUCH WOULD BE LOST BECAUSE OF
DOWNSLOPE EAST OF THE ALLEGHANYS. MAIN FRONTAL SYSTEM STILL BACK
TO THE NORTH W-E ACROSS CENTRAL OH TO CENTRAL PA. SYNOPTIC SCALE
MODELS SHOW LITTLE PCPN MAKING INTO OR CWA UNTIL LATE
AFTERNOON/EVENING AND EVEN SOME OVERNIGHT INTO EARLY SUN. SFC-BL
MOISTURE IS LACKING...SO FEEL THIS SYSTEM OVERALL WILL BE QUITE
LACKLUSTER FOR OUR CWA. INSTABILITY IS LACKING...SO HAVE REMOVED
MENTION OF VCTS EXCEPT FOR LYH AND DAN WHERE BETTER HEATING AND
INSTABILITY COULD BE REALIZED BY AFTERNOON. OTHERWISE...HAVE JUST
INCLUDED VCSH FOR NOW. CIGS SHOULD REMAIN VFR FOR THE MOST PART
THROUGHOUT THE DAY AT ALL SITES. ANY EARLY MORNING FOG WILL
DISSIPATE QUICKLY AFTER DAYBREAK...AND OVERALL THERE IS VERY
LITTLE THIS MORNING ANYWAY BECAUSE OF THE EXTENSIVE MID/HIGH
CLOUDS STREAMING ACROSS THE REGION. BULK OF ANY SHRA ACTIVITY
SHOULD PASS THROUGH THE CWA IN THE 20Z NORTH TO 04Z SOUTH...WITH
VERY LITTLE EXPECTED SW AREAS. OVERNIGHT...A FEW -SHRA MAY DEVELOP
ACROSS WV AND MOVE TOWARD THE NEW RIVER/ROANOKE VALLEY BEFORE
DISSIPATING. MOSTLY VFR CIGS EXPECTED WITH THIS ACTIVITY AS WELL.
THE EXCEPTION TO CIGS OVERNIGHT WILL BE IN UPSLOPE AREAS OF SE
WV...WHERE MVFR CIGS/MVFR VSBYS COULD DEVELOP FROM BLF-
LWB...ESPECIALLY BLF AS TYPICAL WITH THIS SCENARIO. WINDS WSW
5-8KTS TODAY...BECOMING WNW-NW BEHIND THE FRONT OVERNIGHT AT
SPEEDS OF 5-7KTS.
MEDIUM TO HIGH CONFIDENCE IN CIGS THROUGH TAF VALID PERIOD.
MEDIUM TO HIGH CONFIDENCE IN VSBYS THROUGH TAF VALID PERIOD.
HIGH CONFIDENCE IN WIND SPD/DIR THROUGH TAF VALID PERIOD.
MEDIUM TO HIGH CONFIDENCE IN LIMITED TSRA POTENTIAL THIS
AFTERNOON/EVENING.
EXTENDED AVIATION DISCUSSION...
VFR CONDITIONS EXPECTED SUN-MON...OUTSIDE SOME EARLY MORNING MVFR
CIGS SE WV SITES. SPOTTY AFTERNOON CONVECTION POSSIBLE TUE
AFTERNOON...MAINLY LYH/DAN/ROA. WEDNESDAY THROUGH FRIDAY BRINGS
WIDESPREAD CONVECTION BACK TO THE CWA...WITH ATTENDANT LOWER
CIGS/VSBYS AS TROPICAL MOISTURE RETURNS TO THE AREA AND A QUASI-
STATIONARY FRONTAL BOUNDARY DRIFTS SLOWLY SOUTHWARD THROUGH THE
AREA.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...WERT
NEAR TERM...KK/WERT
SHORT TERM...RAB
LONG TERM...RAB/WP
AVIATION...RAB/WERT
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
750 AM EDT SAT AUG 3 2013
.SYNOPSIS...
A COLD FRONT WILL MOVE SOUTHEAST THROUGH THE AREA LATE TODAY INTO
TONIGHT...PRECEDED AND ACCOMPANIED BY SHOWERS AND THUNDERSTORMS.
HIGH PRESSURE FOLLOWING THE FRONT WILL BRING DRIER AND COOLER AIR
BACK INTO THE REGION SUNDAY INTO MONDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 355 AM EDT SATURDAY...
SCATTERED SHOWERS CURRENTLY MOVING EAST OUT OF EASTERN KY AND WV
ON NOSE OF ISENTROPIC LIFT ZONE MAXIMIZED IN 850-700 MILLIBAR
LAYER...AND WILL LIKELY CONTINUE EAST INTO NORTHWESTERN PORTION OF
THE BLACKSBURG FORECAST AREA THROUGH THE DAYBREAK HOURS BEFORE
DISSIPATING EAST OF THE BLUE RIDGE BY MID MORNING AS AREA
ENCOUNTERS INCREASINGLY DOWNSLOPE FLOW. OTHERWISE...EXPECT TO SEE
ANY EARLY MORNING FOG IN MOUNTAIN VALLEYS...AND ACROSS SOUTHSIDE
VA INTO NORTH CENTRAL NC IN VICINITY OF OLD FRONTAL BOUNDARY
RAPIDLY DISSIPATE WITH ONSET OF DAYTIME HEATING.
TRICKY FORECAST FOR REST OF TODAY AS A COMBINATION OF WEATHER
FEATURES COMPETE FOR ATTENTION. WIDESPREAD AREA OF SHOWERS
CURRENTLY OVER OH VALLEY ASSOCIATED WITH FIRST IN SERIES OF SHORT
WAVE TROFS THAT WILL PROGRESSIVELY CARVE OUT UPPER TROF OVER THE
NORTHEASTERN PORTION OF THE NATION THIS WEEKEND...DRIVING COOL
FRONT INTO AND THROUGH THE BLACKSBURG FORECAST AREA TONIGHT. LOCAL
WRF AND HRRR MODELS INDICATING THAT PRECEDING AREA OF SHOWERS MAY
HELP GENERATE AND PUSH OUTFLOW BOUNDARY SOUTHEAST OUT AHEAD OF
THE FRONT INTO NORTHERN THIRD OF THE BLACKSBURG FORECAST AREA THIS
AFTERNOON. DESPITE RATHER LACKLUSTER MID LEVEL INSTABILITY...AND
POTENTIAL OF AT LEAST SOME OFFSET OF INSOLATIVE POTENTIAL DUE TO
LINGERING MID AND HIGH LEVEL CLOUDS...WIDELY SCATTERED TO
SCATTERED SHOWERS/THUNDERSTORMS ARE EXPECTED TO DEVELOP BY/DURING
THE EARLY TO MID AFTERNOON IN ASSOCIATED CONFLUENCE ZONE...
ESPECIALLY NORTH OF HIGHWAY 460...AND ACROSS WESTERN FLANKS OF THE
APPALACHIANS AS WESTERLY UPSLOPING WINDS PROVIDE SOME NEEDED
UPWARD ASSIST.
MUCH BETTER INSTABILITY REMAINS LOCKED UP OVER SOUTHSIDE VA INTO
NORTH CENTRAL NC WHERE MUCH DEEPER LOW LEVEL/TROPICAL MOISTURE
RESIDES IN VICINITY OF OLD FRONT. SHORT RANGE AND MESOSCALE
MODELS HIGHLIGHT THIS AREA FOR ADDITIONAL SCATTERED
SHOWER/THUNDERSTORM DEVELOPMENT...ALTHOUGH ANY NORTHWARD PUSH OF
THIS AIRMASS INTO VA APPEARS UNLIKELY CONSIDERING SLOW VEERING OF
WINDS AS ZONAL FLOW INCREASES OVER AREA.
IN LIGHT OF THE ABOVE...BEST THREAT FOR WIDELY SCATTERED TO
SCATTERED SHOWERS/THUNDERSTORMS TODAY WILL BE ACROSS THE
NORTH...NORTHWEST...AND SOUTHEAST PORTION OF THE BLACKSBURG
FORECAST AREA...WITH RELATIVE MINIMUM (MORE ISOLATED) THREAT FROM
THE FOOTHILLS OF NORTHWEST NC NORTHEAST TOWARD FARMVILLE VA.
SEVERE WEATHER THREAT AT THE PRESENT TIME APPEARS TO BE REMOTE.
LOSS OF DAYTIME HEATING AND LITTLE TO NO DYNAMIC SUPPORT AS SHORT
WAVE ENERGY REMAINS WELL NORTH OF THE BLACKSBURG AREA SHOULD
SUPPORT DEMISE OF LINGERING SHOWER/THUNDERSTORM ACTIVITY IN MOST
AREAS BEFORE MIDNIGHT TONIGHT...BUT WITH A LOW THREAT OF SOME
STRAY SHOWERS REMAINING INTO THE EARLY MORNING HOURS ACROSS THE
SOUTHWESTERN MOUNTAINS WHERE A BIT DEEPER MOISTURE PROFILE WILL
RESIDE AS COLDER AIR FOLDS INTO AREA FROM THE NORTH.
MOS GUIDANCE GENERALLY ACCEPTED FOR THE NEAR TERM PERIOD...WITH
HIGHS TODAY IN THE 70S ACROSS THE HIGHER TERRAIN TO 80S
ELSEWHERE...WITH OVERNIGHT LOWS MAINLY IN THE 60S EXCLUDING SOME
MID TO UPPER 50S IN SOME OF THE DEEPER MOUNTAIN VALLEYS.
&&
.SHORT TERM /SUNDAY THROUGH TUESDAY NIGHT/...
AS OF 430 AM EDT SATURDAY...
A BRIEF AMPLIFICATION OF THE NW FLOW ALOFT WILL ALLOW A FAIRLY
SUBSTANTIAL AREA OF COOL...DRY HIGH PRESSURE TO SPREAD SE ACROSS
THE REGION BEHIND A COLD FRONT WHICH WILL PUSH INTO SOUTH CAROLINA
BEFORE STALLING MONDAY. THIS WILL PROVIDE THE FORECAST AREA WITH
A RESPITE FROM THE INCESSANT SHRA/TSRA ACTIVITY OF RECENT DAYS AND
ALLOW A QUITE DRY AIR MASS TO SPREAD THROUGH THE AREA BY EARLY
MON. ANY REMNANT -SHRA AROUND DAYBREAK SUN...SHOULD DISSIPATE
QUICKLY AND SKIES SHOULD CLEAR EAST OF THE ALLEGHANYS. CANNOT RULE
OUT LINGERING UPSLOPE SC ACROSS SE WV...BUT OVERALL EVEN THOSE
AREAS SHOULD CLEAR OUT BY EVENING.
TEMPS SUN SHOULD BE BELOW NORMAL WEST OF THE ALLEGHANYS...BUT
NEAR NORMAL ACROSS THE PIEDMONT FROM STRONG INSOLATION AND
DOWNSLOPE NW FLOW. MON MORNING SHOULD BE THE COOLEST MORNING OF
THE NEXT SEVEN DAYS AND RIVAL THE RECENT PAST COUPLE OF COOL
SPELLS WHERE MIN TEMPS DIPPED INTO THE UPPER 40S IN DEEPER
MOUNTAIN VALLEYS WITH WIDESPREAD 50S WEST OF THE BLUE
RIDGE...LOWER 60S ACROSS THE PIEDMONT.
FOR TUE...THE FIRST IN A LONG SERIES OF NW FLOW DISTURBANCES
TRACKS ACROSS THE REGION AS A PRONOUNCED BAROCLINIC ZONE BEGINS TO
SET UP ACROSS THE REGION FROM NW-SE FROM THE OHIO VALLEY TOWARD
THE MID-ATLANTIC...BEGINNING WHAT SHOULD BE A 3-5 DAY PERIOD OF
QUITE ACTIVE CONVECTIVE WEATHER. FOR TUE...SFC MOISTURE WILL JUST
BE RECOVERING...SO NOT EXPECTING AN OVERLY ACTIVE CONVECTIVE DAY
JUST YET. THE MON SFC HIGH WILL MOVE TO A POSITION OFF THE MID-
ATLANTIC COAST AND ALLOW A WEAK WEDGE SITUATION TO EVOLVE EAST OF
THE BLUE RIDGE. FOR NOW...HAVE ADVERTISED LOW CHC POPS MOST
AREAS...BUT THE BEST THREAT FOR PCPN APPEARS TO BE EAST OF OR NEAR
THE ALLEGHANYS AT THIS TIME WHERE LOW-LEVEL MOISTURE CONVERGENCE
AND SFC TD IS MAXIMIZED AND DIFFERENTIAL HEATING MAY HELP SPARK
INITIAL CONVECTION DURING THE AFTERNOON. MAX/MIN TEMPS WILL BEGIN
TO RECOVER FROM THE MON COOL SPELL AND SHOULD BE CLOSER TO
NORMAL...EXCEPT STILL SLIGHTLY BELOW NORMAL IN THE FAR N-NW PART
OF THE CWA.
&&
.LONG TERM /WEDNESDAY THROUGH FRIDAY/...
AS OF 445 AM EDT SATURDAY...
AS NOTED THE PAST SEVERAL DAYS...THIS PERIOD LOOKS TO BE QUITE
ACTIVE WITH REGARD TO CONVECTION. THE FLOW WILL TREND TOWARD AN
INCREASINGLY ZONAL FLOW WITH A SERIES OF EMBEDDED DISTURBANCES
ALOFT. A WEAK COLD FRONT WILL BEGIN TO ENTER THE NW PART OF THE
CWA BY THU...THEN ATTEMPT TO PUSH SLOWLY SOUTHEASTWARD THU-FRI.
HOW FAR S-SE THE FRONT MOVES BEFORE STALLING IS HIGHLY
QUESTIONABLE GIVEN THE INCREASING ZONAL FLOW IN PLACE AND A
SUBTROPICAL RIDGE BUILDING ACROSS THE SE STATES. BOTH THE GFS AND
ECMWF TRY TO PUSH THE FRONT COMPLETELY SOUTH OF OUR CWA BY
SATURDAY AS IT STRENGTHENS THE NW FLOW JUST ENOUGH TO DO SO...BUT
AS NOTED...THAT IS SOMEWHAT DOUBTFUL.
AT ANY RATE...WED-THU LOOK QUITE ACTIVE AND
PROBLEMATIC...ESPECIALLY IN TERMS OF FLASH FLOOD POTENTIAL. PWATS
REACH OR EXCEED 2.0 INCHES ACROSS MUCH OF THE CWA WED- THU
AFTERNOON. THIS COMBINED WITH PERIODIC AMPLE UPPER SUPPORT FROM
EMBEDDED SHORT WAVES AND THE VERY WET ANTECEDENT CONDITIONS WILL
HAVE TO BE WATCHED VERY CAREFULLY. WITH A NEARLY STALLED OR QUASI-
STATIONARY FRONTAL BOUNDARY DRAPED ACROSS THE REGION AND FAVORABLE
SUPPORT...TRAINING OF SHRA/TSRA ACTIVITY APPEARS LIKELY.
FURTHERMORE...INSTABILITY LOOKS QUITE HEALTHY WITH CAPES REACHING
2000 J/KG OR GREATER WED AND THU AFTERNOON ACROSS MUCH OF THE CWA.
THUS...A FEW STRONG TO SEVERE THUNDERSTORMS ALSO APPEAR LIKELY.
HAVE INTRODUCED THE MENTION OF HEAVY RAIN TO THE ZFP FOR THESE
PERIODS AND WILL ALSO CONTINUE TO INCLUDE THE THREAT OF HEAVY RAIN
AND ISOLATED SEVERE IN THE HWO.
HUMIDITY LEVELS WILL BE QUITE HIGH THROUGH THE EXTENDED
PERIODS...SO THERE WILL BE LITTLE COOLING AT NIGHT. BY THE SAME
TOKEN...MAX TEMPS SHOULD REMAIN NEAR NORMAL...PERHAPS SLIGHTLY BELOW
IN AREAS THAT HAVE ENOUGH CLOUD COVER/PCPN TO LIMIT HEATING.
NONETHELESS...IT WILL BE QUITE MUGGY AND MUCH MORE UNCOMFORTABLE
THAN THE BEGINNING OF THE WEEK.
&&
.AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...
AS OF 730 AM EDT SATURDAY...
FIRST BAND OF -SHRA ASSOCIATED WITH UPSTREAM TROUGH/FRONTAL SYSTEM
HAS ALREADY PASSED THROUGH THE CWA. ONLY BLF REPORTED -RA AND A
TRACE OF PCPN...AS EXPECTED MUCH WOULD BE LOST BECAUSE OF
DOWNSLOPE EAST OF THE ALLEGHANYS. MAIN FRONTAL SYSTEM STILL BACK
TO THE NORTH W-E ACROSS CENTRAL OH TO CENTRAL PA. SYNOPTIC SCALE
MODELS SHOW LITTLE PCPN MAKING INTO OR CWA UNTIL LATE
AFTERNOON/EVENING AND EVEN SOME OVERNIGHT INTO EARLY SUN. SFC-BL
MOISTURE IS LACKING...SO FEEL THIS SYSTEM OVERALL WILL BE QUITE
LACKLUSTER FOR OUR CWA. INSTABILITY IS LACKING...SO HAVE REMOVED
MENTION OF VCTS EXCEPT FOR LYH AND DAN WHERE BETTER HEATING AND
INSTABILITY COULD BE REALIZED BY AFTERNOON. OTHERWISE...HAVE JUST
INCLUDED VCSH FOR NOW. CIGS SHOULD REMAIN VFR FOR THE MOST PART
THROUGHOUT THE DAY AT ALL SITES. ANY EARLY MORNING FOG WILL
DISSIPATE QUICKLY AFTER DAYBREAK...AND OVERALL THERE IS VERY
LITTLE THIS MORNING ANYWAY BECAUSE OF THE EXTENSIVE MID/HIGH
CLOUDS STREAMING ACROSS THE REGION. BULK OF ANY SHRA ACTIVITY
SHOULD PASS THROUGH THE CWA IN THE 20Z NORTH TO 04Z SOUTH...WITH
VERY LITTLE EXPECTED SW AREAS. OVERNIGHT...A FEW -SHRA MAY DEVELOP
ACROSS WV AND MOVE TOWARD THE NEW RIVER/ROANOKE VALLEY BEFORE
DISSIPATING. MOSTLY VFR CIGS EXPECTED WITH THIS ACTIVITY AS WELL.
THE EXCEPTION TO CIGS OVERNIGHT WILL BE IN UPSLOPE AREAS OF SE
WV...WHERE MVFR CIGS/MVFR VSBYS COULD DEVELOP FROM BLF-
LWB...ESPECIALLY BLF AS TYPICAL WITH THIS SCENARIO. WINDS WSW
5-8KTS TODAY...BECOMING WNW-NW BEHIND THE FRONT OVERNIGHT AT
SPEEDS OF 5-7KTS.
MEDIUM TO HIGH CONFIDENCE IN CIGS THROUGH TAF VALID PERIOD.
MEDIUM TO HIGH CONFIDENCE IN VSBYS THROUGH TAF VALID PERIOD.
HIGH CONFIDENCE IN WIND SPD/DIR THROUGH TAF VALID PERIOD.
MEDIUM TO HIGH CONFIDENCE IN LIMITED TSRA POTENTIAL THIS
AFTERNOON/EVENING.
EXTENDED AVIATION DISCUSSION...
VFR CONDITIONS EXPECTED SUN-MON...OUTSIDE SOME EARLY MORNING MVFR
CIGS SE WV SITES. SPOTTY AFTERNOON CONVECTION POSSIBLE TUE
AFTERNOON...MAINLY LYH/DAN/ROA. WEDNESDAY THROUGH FRIDAY BRINGS
WIDESPREAD CONVECTION BACK TO THE CWA...WITH ATTENDANT LOWER
CIGS/VSBYS AS TROPICAL MOISTURE RETURNS TO THE AREA AND A QUASI-
STATIONARY FRONTAL BOUNDARY DRIFTS SLOWLY SOUTHWARD THROUGH THE
AREA.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...WERT
NEAR TERM...WERT
SHORT TERM...RAB
LONG TERM...RAB/WP
AVIATION...RAB/WERT
AREA FORECAST DISCUSSION
NWS TUCSON AZ
915 AM MST SAT AUG 3 2013
.SYNOPSIS...SCATTERED MAINLY AFTERNOON AND EVENING THUNDERSTORMS
WILL CONTINUE INTO NEXT WEEK WITH NEAR NORMAL TEMPERATURES.
&&
.DISCUSSION...THIS MORNINGS KTWC SOUNDING WAS CONSIDERABLY DRIER
THAN YESTERDAY AT THIS TIME. FRIDAY MORNINGS SOUNDING HAD A
PRECIPITABLE WATER OF 1.81 INCHES...WHILE TODAYS PW VALUE WAS DOWN
TO 1.38 INCHES. WITH PW`S LOWER TODAY THAN YESTERDAY EXPECT THE
FLOODING THREAT TO BE LESSER TODAY THAN YESTERDAY. THE UNMODIFIED
SOUNDING FROM THIS MORNING HAD A LIFTED INDEX OF MINUS 5 AND A CAPE
OF AROUND 2000 J/KG. HOWEVER...MODIFYING THE SOUNDING USING
T=99;TD=53 YIELDS A LIFTED INDEX OF AROUND MINUS 2 AND A CAPE OF
AROUND 200-500 J/KG.
WATER VAPOR IMAGERY SHOWS A DISTURBANCE OVER SOUTHERN SONORA MEXICO
AND MOVING NORTH NORTHWEST. THE MOST RECENT HRRR SHOWS ACTIVITY
DEVELOPING TODAY MAINLY BETWEEN TUCSON AND THE INTERNATIONAL
BORDER...AS WELL AS OVER THE TOHONO O`ODHAM NATION AND DRIFTING EAST
OF THE TUCSON AREA DURING THE MID TO LATE AFTERNOON HOURS. LOCAL WRF
MODEL ALSO SHOWS A SIMILAR SOLUTION...BUT WITH THE ACTIVITY FARTHER
EAST THAN THE HRRR. AT ANY RATE...THE LOW END CHANCE CATEGORY POPS
FOR TODAY SEEM TO BE ON TRACK...SO NO CHANGES PLANNED AT THIS
TIME...BUT WILL MONITOR AND ADJUST THE FORECAST BASED ON SATELLITE
AND RADAR TRENDS. OTHERWISE...THE POP FORECAST FOR THE REMAINDER OF
TODAY IS IN GOOD SHAPE.
AS OF 16Z (9 AM MST)...TEMPERATURES ACROSS THE REGION RANGED FROM
THE MID 70S TO THE MID 80S. WILL MAKE SOME ADJUSTMENTS TO THE SHORT
TERM HOURLY TEMPERATURE GRIDS TO BETTER REFLECT CURRENT TRENDS.
OTHERWISE...THINK THE HIGHS FOR THE AFTERNOON ARE ON TRACK.
FOR DETAILS REGARDING THE FORECAST BEYOND TODAY...PLEASE REFER TO
THE PREVIOUS DISCUSSION BELOW.
&&
.AVIATION...FEW-SCT CLOUDS AT 12-15K FT AGL...AND SCT CLOUDS AOA 20K
FT AGL THRU 03/18Z. AFT 03/18Z...SCT CLOUDS AT 5-9K FT AGL.
ISOLD-SCT TSRA DEVELOPING AFT 03/18Z AND CONTINUING THRU 04/05Z.
WIND GUSTS TO 45 KTS NEAR ANY TSRA...AS WELL AS LOCAL MVFR/IFR
CIGS/VSBYS. OTHERWISE...SURFACE WIND GENERALLY LESS THAN 10 KTS THRU
04/16Z. AVIATION DISCUSSION NOT UPDATED FOR TAF AMENDMENTS.
&&
.FIRE WEATHER...MOISTURE WILL REMAIN IN PLACE ACROSS THE REGION
THROUGH NEXT WEEK...RESULTING IN A CHANCE OF MAINLY AFTERNOON AND
EVENING SHOWER AND THUNDERSTORM ACTIVITY ACROSS SOUTHEAST ARIZONA.
OUTSIDE OF GUSTY THUNDERSTORM OUTFLOWS...WINDS DURING THIS PERIOD
ARE EXPECTED TO BE LIGHT...GENERALLY LESS THAN 15 MPH AND DIURNALLY
DRIVEN.
&&
.PREVIOUS DISCUSSION...UPPER HIGH CELL REMAINED CENTERED OVER TEXAS
THIS MORNING WITH A MOIST SOUTHERLY MID AND UPPER LEVEL FLOW IN
PLACE. LATEST MODELS KEEP THE UPPER HIGH CENTERED OVER TEXAS THROUGH
MOST OF THE UPCOMING WEEK. WITH VERY LITTLE CHANGE IN THE WEATHER
PATTERN...RAIN CHANCES SHOULD REMAIN ABOUT THE SAME THE NEXT FEW
DAYS. EVENTUALLY...MEDIUM RANGE MODELS DEEPEN A TROUGH OF LOW
PRESSURE ALONG THE WEST COAST WITH THE HIGH SHIFTING FARTHER
SOUTHEAST LATE NEXT WEEK. THIS COULD BRING SOME DRIER AIR INTO THE
AREA FROM THE WEST RESULTING IN LESS THUNDERSTORM ACTIVITY BY AROUND
THURSDAY.
&&
.TWC WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...YOUTUBE...AND AT WEATHER.GOV/TUCSON
AREA FORECAST DISCUSSION
NWS PUEBLO CO
255 PM MDT SAT AUG 3 2013
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 249 PM MDT SAT AUG 3 2013
...FLASH FLOODING THREAT FOR THE BURN SCARS AND SEVERE THUNDERSTORM
THREAT FOR THE SOUTHEAST PLAINS THROUGH THIS EVENING...
RICH LOW LEVEL MOISTURE IN PLACE ACROSS SOUTHEAST PLAINS AS OF EARLY
THIS AFTERNOON...WITH SFC DEW POINTS IN THE 60S. THIS IS BEING
ADVECTED IN BY LOW LEVEL EASTERLY FLOW. CLOUD COVER HAS HUNG IN
LONGER ACROSS THE PLAINS THIS AFTERNOON BUT IS ERODING ON WESTWARD
EDGE WHICH SHOULD ERODE CIN FROM WEST TO EAST AS THE AFTERNOON
PROGRESSES. MEANWHILE...MONSOON PLUME CONTINUES TO LAY ACROSS THE
REGION CAUGHT UP IN SOUTHWEST FLOW AROUND WEST SIDE OF SFC HIGH AND
SFC DEW POINT ACROSS THE MOUNTAINS ARE QUITE RESPECTABLE...IN THE
40S WITH SOME LOWER 30S ACROSS INTERIOR VALLEY OF LAKE/CHAFFEE
COUNTIES.
FOR THE REMAINDER OF THIS AFTERNOON AND EVENING...THUNDERSTORMS OVER
THE MOUNTAINS WILL SPREAD EASTWARD ACROSS THE ADJACENT PLAINS WITH
MODELS SUGGESTING ONE OR MORE THUNDERSTORM COMPLEXES TAKING SHAPE
AROUND 03Z BEFORE DROPPING TO THE SOUTHEAST INTO SOUTHWEST KS AND
TX/OK PANHANDLES TOWARDS MORNING. SPC MESO ANALYSIS AS OF 18Z
SHOWING 2000+ J/KG OF CAPE. 0-6KM SHEARS WILL BE RUNNING AROUND
30-35 KTS OF DEEP LAYER SHEAR. THUS...MULTICELL STORMS WILL PROBABLY
BE THE MAIN STORM THREAT...THOUGH COULD NOT RULE OUT AN ISOLATED
SUPERCELL ESPECIALLY WHERE LOW LEVEL EASTERLIES MAXIMIZE. THIS
WOULD MOST LIKELY OCCUR ACROSS NORTHERN SECTIONS OF THE FORECAST
AREA...PARTICULARLY KIOWA COUNTY.
OF POTENTIALLY EQUAL OR GREATER CONCERN WILL BE POTENTIAL FOR FLASH
FLOODING ON THE BURN SCARS...PARTICULARLY WALDO AND BLACK FOREST.
SOUTHEAST UPSLOPE FLOW COMBINED WITH HEATING...AND WEAK SHORTWAVE
ENERGY EMBEDDED IN MONSOON PLUME ALOFT SHOULD TRIGGER THUNDERSTORMS
OVER THE PIKES PEAK REGION THROUGH 2 PM...WITH A LINE OF
THUNDERSTORMS MOVING OFF TO THE EAST ACROSS THE WALDO AND BLACK
FOREST BURN SCARS BETWEEN 3 AND 6 PM. A MYRIAD OF SHORT RANGE HIGH
RES MODELS SHOW THIS...THOUGH WITH VARYING TIMING. OF COURSE...HAVE
SEEN THIS BEFORE IN THE MODELS AND HAD STORMS MIRACULOUSLY SPARE THE
BURN SCARS...BUT DEW POINTS SO HIGH (40S AND 50S) THREAT SHOULD BE
FAIRLY HIGH TODAY. FLASH FLOOD WATCH STILL LOOKS ON TRACK. THINK
THREAT SHOULD DIMINISH AFTER 8 PM...BUT HRRR OCCASIONALLY SHOWS
ANOTHER ROUND MOVING OFF AROUND 04Z SO WILL MAINTAIN THE MIDNIGHT
END TIME OF THE WATCH FOR NOW. FREQUENTLY THE HRRR OVERESTIMATES
THE INTENSITY OF ANY TRAILING ROUNDS OF CONVECTION.
THE WEST FORK BURN SCAR IS ALSO UNDER THE GUN TODAY FOR FLASH
FLOODING...THOUGH THREAT DOES NOT LOOK AS HIGH AS YESTERDAY. WITH
PRECIP WATERS RUNNING AROUND 150% OF NORMAL ACROSS THE WESTERN
PORTIONS OF CO...HEAVY RAIN WILL BE A THREAT WITH ANY THUNDERSTORMS
WHICH COULD CAUSE FLASH FLOODING SHOULD IT IMPACT THE WEST FORK BURN
SCAR. SO WILL BE MONITORING THIS REGION AS WELL.
OVERNIGHT...ACTIVITY SHOULD SHIFT EASTWARD AND EXIT THE AREA WITH
STRATUS SPREADING/DEVELOPING ACROSS SOUTHEAST COLORADO OVERNIGHT.
SUNDAY WILL BE HUMID AGAIN ACROSS THE SOUTHEAST PLAINS WITH DEW
POINTS IN THE 50S AND 60S IN THE MORNING AND MONSOON PLUME STILL
OVER THE REGION. MODELS SUGGEST LESS CONVECTION TOMORROW...AND EVEN
DRY SFC DEW POINTS ACROSS THE SOUTHEAST MTS A LITTLE IN THE
AFTERNOON STILL LOOKING AT CAPES AROUND 1500 J/KG ACROSS THE FAR
EAST PLAINS AND WITH MONSOON PLUME STILL OVERHEAD...AT LEAST THE
TYPICAL SCATTERED AFTERNOON AND EVENING THUNDERSTORMS. BURN SCARS
WILL BE UNDER THE GUN AGAIN AS USUAL...BUT THREAT APPEARS A LITTLE
LOWER THAN TODAY...SO WILL NOT HOIST ANY WATCHES AT THIS TIME.
LATER SHIFTS CAN GET A LOOK AT THE LATEST RUNS AND REASSESS.
OTHERWISE...TEMPERATURES TOMORROW SHOULD SKEW SLIGHTLY WARMER THAN
THOSE OF TODAY.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 249 PM MDT SAT AUG 3 2013
...SEASONAL MONSOON WILL REMAIN IN PLACE THROUGH NEXT WEEK...
MOIST PATTERN WILL CONTINUE. SOUTHWEST MONSOON WILL CONTINUE TO
TAKE AIM AT SOUTHERN COLORADO THROUGH MOST OF NEXT WEEK.
ADDITIONALLY...A LARGE UPPER TROUGH OVER THE NORTHERN SOUTHERN
CANADA AND THE NORTHERN TIER OF THE US...WILL SEND SURFACE
BOUNDARIES SOUTH THROUGH THE CENTRAL PLAINS AT TIMES...BACKING
THE MOISTURE UP AGAINST THE MOUNTAINS. THIS PATTERN SHOULD KEEP
PLENTY OF LOW LEVEL MOISTURE IN PLACE ACROSS THE PLAINS AND EAST
SLOPES OF THE MOUNTAINS. ALSO...PERIODS OF ENHANCED UPSLOPE FLOW
BEHIND THE BOUNDARIES WILL HELP TO LIFT THE AIR AND SQUEEZE OUT THE
PRECIPITATION ON A MORE WIDESPREAD BASIS ACROSS THE AREA. SO...ALL
SEEMS IN PLACE FOR A RATHER WET PERIOD ACROSS SOUTHERN
COLORADO...WITH PERIODS OF HEAVY RAIN AND FLASH FLOODING POSSIBLE
EACH DAY OF NEXT WEEK. SPECIFICS OF THE FORECAST ARE DIFFICULT BUT
INDICATIONS ARE THAT WE COULD SEE CONVECTIVE COMPLEXES AFFECTING THE
PLAINS MONDAY AND TUESDAY NIGHTS...A MORE WIDESPREAD AREA OF
PRECIPITATION WEDNESDAY INTO THURSDAY...AND THEN MORE SCATTERED
PRECIPITATION AGAIN FRIDAY INTO SATURDAY. ALL OF THESE DETAILS
ARE SUBJECT TO CHANGE. STAY TUNED. LW
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 249 PM MDT SAT AUG 3 2013
THUNDERSTORMS COULD AFFECT ALL THREE TAF SITES THROUGH THIS EVENING
WITH KCOS HAVING THE GREATEST RISK. WILL CARRY A TEMPO GROUP FROM
21Z TO 01Z TODAY FOR KCOS AND ADJUST AS NECESSARY BASED ON RADAR
TRENDS. KPUB AND KALS ALSO CARRY A THREAT FOR -TSRA BUT WILL
MAINTAIN VCTS FOR NOW UNTIL RADAR TRENDS BECOME MORE CLEAR. LOCAL
ERRATIC WIND GUSTS TO 40 KTS WILL BE POSSIBLE ALONG WITH MVFR
CIGS/VIS WITH TSRA. A SEVERE THUNDERSTORM RISK ALSO LIES ACROSS THE
SOUTHEAST PLAINS INCLUDING THE KCOS AND KPUB TAF SITES...BUT RISK AT
THIS POINT LOOKS TOO LOW TO MENTION GS OR GUSTS OVER 50 KTS IN THE
TAF. THIS TOO WILL BE MONITORED. KALS WILL SEE POTENTIAL FOR -TSRA
IN VCNTY AFTER 20Z. LOCALLY HEAVY RAIN WITH MVFR CIGS/VIS WITH
THUNDERSTORMS WILL BE A POSSIBILITY THERE AS WELL BUT WITH LESS OF A
SEVERE THUNDERSTORM POTENTIAL. EXPECT -TSRA THREAT TO DIMINISH AFTER 02Z
WITH KCOS AND KPUB SEEING MVFR TO IFR STRATUS MOVING IN AFTER 06Z.
THIS WILL PERSIST UNTIL 15-16Z...FOR KPUB...AND UNTIL AT LEAST 17Z
FOR KCOS. -KT
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH UNTIL MIDNIGHT MDT TONIGHT FOR COZ081-082-084-
085.
&&
$$
SHORT TERM...KT
LONG TERM...LW
AVIATION...KT
AREA FORECAST DISCUSSION
NWS PEACHTREE CITY GA
349 PM EDT SAT AUG 3 2013
SHORT TERM /TONIGHT THROUGH MONDAY/...
LOW AMPLITUDE SHORTWAVE BROUGHT AN AREA OF SHOWERS AND THUNDERSTORMS
TO TN EARLIER TODAY...BUT HAS FIZZLED OUT ON ITS WAY INTO NORTH
GEORGIA. AHEAD OF THE BOUNDARY...CONVECTION HAS BEEN FIRING ACROSS
AL...AND EXPECT MAINLY ISOLATED THUNDERSTORMS /POSSIBLY SCATTERED/
ACROSS NORTH GEORGIA AS WELL. EXPECT MUCH OF THE METRO AREA TO BE
QUIET THROUGH THE AFTERNOON AS CONVECTION FOCUSES AHEAD OF THE SHORT
WAVE...AND ACROSS FAR SOUTHERN PORTIONS OF THE CWA WHERE THERE IS
BETTER INSTABILITY /CAPE 2000-2500 J/KG/. LOCAL WRF AND NAM REALLY
KEEP ACTIVITY ACROSS THE AREA TO A MINIMUM...WITH ANY CONVECTION
TAPERING OFF BY 00Z TONIGHT. HRRR SOLUTIONS DIFFER IN THE LATEST
MODEL RUNS COMPARED TO EARLIER CYCLES...AND NOW ADVERTISE CONVECTION
PUSHING INTO THE NORTH METRO AREA BEFORE FIZZLING OUT INTO THE
EVENING HOURS. FOR NOW...HAVE CONTINUED WITH SLIGHT CHANCE TO CHANCE
POPS ACROSS THE AREAS OF CONCERN...DIMINISHING POPS TO JUST SLIGHT
CHANCE OVERNIGHT.
HIGH PRESSURE RIDGE BUILDS SOUTH INTO THE REGION SUNDAY...PUSHING A
COLD FRONT INTO NORTH GEORGIA AS A RESULT. WITH BEST MOISTURE
REMAINING ACROSS THE SOUTHERN HALF OF THE CWA...LATEST MODELS
SHOWING BETTER CONSENSUS WITH KEEPING ANY PRECIP CHANCES SOUTH OF
THE ATL METRO AREA. HAVE GONE AHEAD AND REMOVED MENTION OF SLIGHT
CHANCE POPS NORTH...WHICH MAY BE A LITTLE RISKY...AND PRIMARILY
FOCUSED SLIGHT TO CHANCE POPS ACROSS THE FAR SOUTHERN CWA.
SOME DISAGREEMENT BETWEEN THE MODELS CONTINUE WITH TIMING AND
COVERAGE OF PRECIP INTO THE REGION MONDAY AS PREVIOUSLY MENTIONED
FRONTAL BOUNDARY SITS OVER THE AREA AS A DISTURBANCE MOVES INTO THE
AREA. HAVE CONTINUED WITH THE SLIGHT CHANCE TO GOOD CHANCE POPS
PREVIOUSLY FORECAST...WITH ONLY MINOR ADJUSTMENTS.
FOR TEMPERATURES...HAVE GENERALLY GONE WITH A MODEL BLEND. A WELCOME
AND NOTICEABLE 3-5 DEGREE COOL DOWN EXPECTED FROM SUNDAY INTO MONDAY
WITH HIGH TEMPERATURES WITH THE FRONT.
31
.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
HAVE ONLY MADE A COUPLE OF TWEAKS TO THE POPS ON A COUPLE OF DAYS
BUT NOTHING SIGNIFICANT...POPS STILL IN SLIGHT CHANCE OR CHANCE
CATEGORY. OTHERWISE THE LONG TERM LOOKS OKAY. TIMING OF A COUPLE
OF SHORT WAVES IN THE NORTHWEST FLOW MAY BE TRICKY BUT THE OVERALL
PATTERN REMAINS THE SAME. PREVIOUS LONG TERM DISCUSSION IS
INCLUDED BELOW.
41
&&
.PREVIOUS...
LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
UNSETTLED WEATHER TO CONTINUE FOR MUCH OF THE LONG TERM.
A FRONTAL BOUNDARY WILL BECOME STATIONARY ACROSS SOUTHERN PORTIONS
OF THE CWFA SUNDAY NIGHT THROUGH THE FIRST PART OF NEXT WEEK.
SEVERAL WAVES OF LOW PRESSURE ARE PROGGED TO MOVE ALONG THE
BOUNDARY...EACH HELPING TO SUPPORT THE DEVELOPMENT OF SHOWERS AND
THUNDERSTORMS THROUGH WEDNESDAY. THE HIGHEST POPS WILL BE DURING THE
AFTERNOON AND EARLY EVENING...BUT THE AIRMASS WILL SUPPORT SOME
ISOLATED ACTIVITY OVERNIGHT.
THE STATIONARY BOUNDARY MAY BECOME DIFFUSE BY THURSDAY.
HOWEVER...WITH HIGH PRESSURE OFF THE EASTERN SEABOARD AND SOUTHERLY
FLOW BRINGING ABUNDANT MOISTURE NORTHWARD FROM THE GULF...SCT
DIURNALLY DRIVEN CONVECTION WILL BE POSSIBLE THURSDAY INTO FRIDAY.
THE NEXT COLD FRONT MAY IMPACT THE CWFA BY THE WEEKEND.
NLISTEMAA
AVIATION...
18Z UPDATE...
ISOLATED TS ACTIVITY EXPECTED ACROSS THE AREA THIS AFTERNOON AND
EVENING...GENERALLY NORTH OF THE NORTHERN TAF SITES...AND SOUTH OF
THE SOUTHERNMOST SITES. SOME INDICATION SHOWERS FROM AL COULD
PERSIST AND MOVE INTO NORTH GEORGIA OVERNIGHT...BUT CHANCES TOO
LOW TO INCLUDE IN TAF AT THIS TIME. WINDS SHOULD STAY TO THE
NW...GENERALLY 8-10KT THIS AFTERNOON...5-8KT OVERNIGHT. SOME LOW
END GUSTS TO 14-16KT POSSIBLE THIS AFTERNOON. SCT MVFR POSSIBLE
09-15Z.
//ATL CONFIDENCE...18Z UPDATE...
HIGH CONFIDENCE ON ALL ELEMENTS.
31
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 71 92 69 87 / 10 10 5 20
ATLANTA 73 90 71 87 / 20 10 10 20
BLAIRSVILLE 67 85 63 82 / 20 10 5 30
CARTERSVILLE 70 90 67 88 / 20 10 5 20
COLUMBUS 75 95 73 92 / 10 20 10 30
GAINESVILLE 72 89 69 85 / 20 10 5 20
MACON 72 95 71 92 / 10 20 10 20
ROME 70 90 66 89 / 20 10 5 20
PEACHTREE CITY 71 91 68 89 / 20 10 10 20
VIDALIA 75 94 74 92 / 20 30 20 30
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...31
LONG TERM....41
AVIATION...31
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
321 PM EDT SAT AUG 3 2013
.SYNOPSIS...
HIGH PRESSURE WILL EXTEND ACROSS THE REGION THROUGH SUNDAY. A
BACKDOOR COLD FRONT WILL DROP SOUTH SUNDAY NIGHT AND STALL ACROSS
SOUTHEAST GEORGIA MONDAY BEFORE DISSIPATING BY TUESDAY. HIGH
PRESSURE WILL THEN REBUILD IN FROM THE NORTHEAST FOR THE REMAINDER
OF NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
SHOWER ACTIVITY CONTINUES TO SLOWLY DEVELOP ALONG THE SEA BREEZE
THIS AFTERNOON. LIGHTNING HAS NOT YET BEEN OBSERVED IN ANY OF THE
CELLS JUST YET AND GOES-EAST SATELLITE DERIVED SOUNDINGS SUGGEST
A SMALL NEGATIVE AREA STILL EXISTS JUST ABOVE 900 MB. AS TEMPERATURES
RISE INTO THE 90S...THIS SHOULD ALLOW PARCELS TO MORE EASILY SURPASS
THE LEVEL OF FREE CONVECTION /LFC/ AND TAP INTO A LARGE AREA OF
CAPE NEARING 3000 J/KG. RAP SOUNDINGS SUPPORT DCAPES IN EXCESS OF
1200 J/KG IN MANY AREAS SO AN ISOLATED SEVERE TSTM OR TWO CAN NOT
BE COMPLETELY RULED OUT WITH DAMAGING WINDS AND FREQUENT CLOUD-TO-
GROUND LIGHTNING. THERE WILL ALSO A POTENTIAL FOR LOCALIZED
FLOODING GIVEN THE WEAK STORM MOTIONS NOTED. PLAN TO MAINTAIN
20-30 PERCENT POPS THROUGH THE EVENING HOURS WITH THE HIGHEST
HOURLY GRIDDED POPS CLUSTERED NEAR THE RESULTANT SEA BREEZE
CIRCULATION. ONCE CONVECTION DISSIPATES THIS EVENING...EXCEPT A
DRY NIGHT WITH ONLY THIN DEBRIS CIRRUS PASSING OVERHEAD. LOWS WILL
RANGE FROM THE LOWER 70S WELL INLAND TO AROUND 80 AT THE BEACHES.
&&
.SHORT TERM /SUNDAY THROUGH TUESDAY/...
SUNDAY...A DRY NORTHWEST WIND SHOULD KEEP CONDITIONS RAIN-FREE TO
START OFF THE WEEK. THE NORTHWEST FLOW WILL LIKELY CONTRIBUTE TO
WARMER THAN NORMAL TEMPS AS THE SEABREEZE REMAINS PINNED ALONG THE
COAST THROUGH EARLY AFTERNOON. LATEST MOS GUIDANCE ALONG WITH
1000-850 MB THICKNESSES SUGGEST OVERALL HIGH TEMPS IN THE LOW TO MID
90S AWAY FROM THE IMMEDIATE COAST. GIVEN THE DURATION OF THE PINNED
SEABREEZE ALONG THE COAST...TEMPS COULD PEAK NEAR 90 ALONG THE
BEACHES. HOWEVER...WARMEST TEMPS WILL LIKELY OCCUR OVER SOUTHEAST
GEORGIA WHERE COMPRESSIONAL HEATING TAKES PLACE AHEAD OF A BACKDOOR
COLD FRONT APPROACHING THE REGION FROM THE NORTH/NORTHEAST.
A SLIGHT CHANCE TO CHANCE OF SHOWERS AND THUNDERSTORMS WILL REMAIN
IN THE FORECAST SUNDAY AFTERNOON/EVENING AS THE BACKDOOR COLD FRONT
APPROACHES FROM THE NORTH/NORTHEAST AND BEGINS TO STALL OVER OR NEAR
SOUTHEAST GEORGIA SUNDAY NIGHT. PRECIP CHANCES AND COVERAGE WILL BE
HIGHEST SUNDAY EVENING INTO THE EARLY OVERNIGHT HOURS IN SOUTHEAST
GEORGIA WHERE MOISTURE REMAINS HIGHEST WITH PWATS NEAR 2.00 INCHES
NEAR THE VICINITY OF STALLED FRONT. OVERNIGHT LOWS SHOULD RANGE IN
THE LOW 70S INLAND TO MID/UPPER 70S ALONG THE COAST.
MONDAY AND TUESDAY....A LARGE MID LVL RIDGE OVER THE SOUTH CENTRAL
UNITED STATES WILL GRADUALLY EXPAND OVER THE SOUTHEAST EARLY NEXT
WEEK AS THE STALLED SFC BOUNDARY LINGERS OVER SOUTHERN PORTIONS OF
THE FORECAST AREA MONDAY BEFORE DISSIPATING AS SFC HIGH PRESSURE
SLIDES IN FROM THE NORTH/NORTHEAST ON TUESDAY. LIGHT ONSHORE WINDS
SUPPORT ABUNDANT LOW LVL MOISTURE OVER THE SOUTHEAST EACH DAY...WITH
A FEW SHOWERS AND/OR THUNDERSTORMS ALONG AN INLAND MOVING SEABREEZE
EACH AFTERNOON. THE GREATEST CONCENTRATION OF CONVECTION IS EXPECTED
OVER SOUTHEAST GEORGIA NEAR THE DISSIPATING BOUNDARY AND INLAND
MOVING SEABREEZE. HIGH TEMPS WILL BE SLIGHTLY COOLER THAN PREVIOUS
DAYS...WITH 1000-850 MB THICKNESSES SUPPORTING OVERALL HIGH TEMPS IN
THE UPPER 80S TO LOWER 90S UNDER PARTLY SUNNY SKIES.
&&
.LONG TERM /TUESDAY NIGHT THROUGH FRIDAY/...
DEEP LAYER RIDGING BUILDS ACROSS THE SOUTHEAST U.S. AND INTO THE
ATLANTIC WATERS. LOW LEVEL SE FLOW WILL PREVAIL THROUGH THE PERIOD
WITH BEST MOISTURE AND CONVERGENCE EXPECTED TO FOCUS INLAND. MAINLY
AFTERNOON AND EARLY EVENING CONVECTION PUSHING INLAND EACH DAY.
MODEL CROSS SECTIONS SHOW MARGINAL DEEP LAYER MOISTURE...AND ALONG
WITH RIDGING ALOFT...EXPECT CONVECTION TO BE SCATTERED AT BEST EACH
AFTERNOON. HAVE KEPT LOW END CHANCE POPS THROUGH THE PERIOD. TEMPS
AROUND NORMAL.
&&
.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
MAINLY VFR CONDITIONS ARE EXPECTED TO PREVAIL TODAY...BUT PERIODIC
REDUCTIONS ARE POSSIBLE AS SHOWERS AND THUNDERSTORMS CONTINUE TO
DEVELOP ALONG THE SEA BREEZE. CHANCES FOR THUNDERSTORMS APPEAR MORE
FAVORABLE AT KCHS GIVEN THE LATEST RADAR TRENDS. THEREFORE...HAVE
INCLUDED A TSRA TEMPO GROUP STARTING AROUND 19Z. LESS CONVECTIVE
COVERAGE IS EXPECTED CLOSER TO KSAV. THEREFORE...WILL EXCLUDED TS IN
TAFS FOR NOW AND WILL AMEND IF NECESSARY. ANY LINGERING CONVECTION
SHOULD DIMINISH AROUND SUNSET...ALLOWING VFR CONDITIONS TO PREVAIL.
EXTENDED AVIATION OUTLOOK...ISOLATED TO SCATTERED AFTERNOON
SHOWERS/THUNDERSTORMS POSSIBLE EACH DAY...WITH A CHANCE OF BRIEF
MVFR CIGS/VSBYS. CHANCES OF MVFR CIGS/VSBYS SHOULD BE HIGHEST AT THE
SAV TERMINAL SUNDAY EVENING/NIGHT AS A BACKDOOR COLD FRONT STALLS
OVER THE AREA.
&&
.MARINE...
TONIGHT...LIGHT WINDS THIS AFTERNOON WILL GRADUALLY VEER SOUTHWEST
AND INCREASE TO 10-15 KT THIS EVENING/OVERNIGHT AS A COLD FRONT
DRAWS CLOSER TO THE REGION. SEAS WILL RESPOND A JUST A LITTLE...
BUT STILL EXPECT SEAS TO RANGE FROM 2-4 FT...HIGHEST OVER THE
OFFSHORE LEGS.
MONDAY THROUGH THURSDAY...CONDITIONS WILL REMAIN WELL BELOW SMALL
CRAFT ADVISORY LEVELS THROUGH THE MIDDLE OF NEXT WEEK. IN
GENERAL...SOUTHWEST WINDS WILL DOMINATE THE WATERS SUNDAY WHILE
REMAINING AT OR BELOW 15 KTS. A BACKDOOR COLD FRONT WILL THEN
REACH THE WATERS SUNDAY NIGHT...THUS VEERING WINDS TO NORTH/NORTHEAST
WITH SPEEDS NEAR 15 KTS AT TIMES. LIGHT WINDS WILL CONTINUE TO
VEER AND BECOME ONSHORE BY MONDAY AS THE FRONT STALLS AND DISSIPATES
ALONG OR NEAR SOUTHERN GEORGIA WATERS ON TUESDAY. SEAS WILL RANGE
FROM 1-3 FT...HIGHEST OVER OUTER GEORGIA WATERS. HIGH PRESSURE
WILL THEN SETTLE OVER THE WATERS THROUGH MIDWEEK WITH POSSIBLY
LONGER PERIOD SWELLS DURING THIS TIME FRAME DUE TO LONGER FETCH
AND THE DURATION OF SOUTHEAST FLOW.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...NONE.
&&
$$
ST/JHP/DPB
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1251 PM CDT SAT AUG 3 2013
.DISCUSSION...
339 AM CDT
THERE ARE NO BIG CONCERNS FOR THE NEXT COUPLE OF DAYS AS COOL AND
DRY HIGH PRESSURE DOMINATES ACROSS THE AREA. HOWEVER...FORECAST
CONCERNS FOR SHOWERS AND THUNDERSTORMS INCREASE AGAIN EARLY NEXT
WEEK. THEREFORE THE MAIN FORECAST CONCERNS WILL BE WITH CONVECTIVE
CHANCES AND TEMPERATURES IN THE EXTENDED.
CURRENTLY A COLD FRONT IS SAGGING SOUTHWARD ACROSS CENTRAL PORTIONS
OF ILLINOIS AND INDIANA. SHOWER AND THUNDERSTORM ACTIVITY HAS
ABATED...AND SHIFTED MOSTLY OUT OF MY AREA...WITH ONLY A FEW
LINGERING SHOWERS FAR SOUTH. OTHERWISE...SKIES ARE CLEARING ACROSS
SOUTHERN WISCONSIN AND FAR NORTHERN ILLINOIS...WITH DEW POINTS
DROPPING INTO THE LOWER 50S. THIS TREND SHOULD CONTINUE ACROSS MY
ENTIRE AREA BY MID MORNING. SURFACE HIGH PRESSURE...CENTERED OVER
NORTH DAKOTA AND INTO THE PRAIRIE PROVIDENCES OF CANADA...WILL
PRODUCE A NORTHERLY FLOW ACROSS THE AREA TODAY. TEMPERATURES LOOK TO
TOP OUT IN THE UPPER 70S TO THE LOW 80S AREA-WIDE...WITH THE
EXCEPTION OF MIDDLE 70S LAKESIDE.
TEMPERATURES TONIGHT WILL LIKELY RADIATE EFFICIENTLY WITH MOSTLY
CLEAR SKIES AND LIGHT WINDS...AS THE SURFACE HIGH DROPS
SOUTHEASTWARD ACROSS MINNESOTA AND WISCONSIN. THIS SHOULD RESULT IN
A CHILLY NIGHT...WITH TEMPERATURES FALLING INTO THE LOWER 50S AWAY
FROM CHICAGO. SUNDAY WILL ALSO BE PLEASANT WITH TEMPERATURES MAINLY
IN THE MID TO UPPER 70S.
THINGS BEGINNING TO GET MORE ACTIVE BY MONDAY AS THE SURFACE HIGH
SHIFT TO THE EAST AND ALLOWS THE LOWER LEVEL FLOW TO BECOME
SOUTHERLY AGAIN. THIS SHOULD ALLOW MOISTURE TO MAKE A QUICK RETURN
TO THE AREA. THIS IN COMBINATION WITH AN FAST AND ACTIVE
NORTHWESTERLY UPPER LEVEL LEVEL FLOW PATTERN...WILL SET THE STAGE
FOR INCREASES IN SHOWERS AND THUNDERSTORMS. IT APPEARS THE FIRST
UPPER LEVEL DISTURBANCE COULD INDUCE ENOUGH LOW LEVEL RESPONSE TO
RESULT IN SHOWERS/STORMS AS EARLY AS MONDAY. I ADDED SLIGHT CHANCE
POPS DURING THE DAY ACROSS MOST OF THE AREA TO ACCOUNT FOR THIS
POSSIBILITY.
THE NEXT AND MORE SIGNIFICANT FORECAST ISSUE WILL BE THE
SIGNIFICANT STORM SYSTEM...WHICH THE MODELS ARE SUGGESTING WILL
DEVELOP ACROSS THE UPPER MIDWEST AND INTO WESTERN ONTARIO TUESDAY
AND TUESDAY NIGHT AS A SIGNIFICANT UPPER LOW GETS DISLODGED FROM THE
HUDSON BAY REGION. THIS SYSTEM LOOKS TO SET UP A PERIOD OF POSSIBLY
SIGNIFICANT CONVECTION ACROSS THE AREA...ALONG WITH A PERIOD OF WARMER
WEATHER TUESDAY AND WEDNESDAY.
THERE ARE UNCERTAINTIES IN THE FINNER SCALE DETAILS OF THIS SYSTEM.
HOWEVER...IT DOES APPEAR THAT WARMER CONDITIONS WILL SET UP FOR
TUESDAY...AND POTENTIAL INTO WEDNESDAY AS WELL AS SOUTHERLY FLOW
AHEAD OF THE DEVELOPING LOW...WILL RESULT IN AN INFLUX OF A
WARMER...MORE HUMID AIRMASS. THE MODEL GUIDANCE APPEARS TO BE
UNDERDOING THE WARM FOR TUESDAY AND POSSIBLY WEDNESDAY AS WELL.
ALTHOUGH THERE WILL BE PERIOD OF CONVECTION AROUND...IT APPEARS
TUESDAY LOOKS TO BE A GOOD CANDIDATE FOR TEMPERATURES TOPPING OUT
IN THE MID TO UPPER 80S...AS 850 AND 925 MB TEMPERATURES ARE
PROGGED TO BE AROUND 18 AND 22 DEGREES C...RESPECTIVELY.
TEMPERATURES ON WEDNESDAY COULD BE JUST AS WARM.
HOWEVER...DIFFERENCES AND UNCERTAINTIES ON THE EXACT TIMING OF THE
COLD FRONTAL PASSAGE ON WEDNESDAY COULD COMPLICATE THINGS. IN
SPITE OF THIS...I DID WARM TEMPERATURES INTO THE LOW TO MID 80S
FOR BOTH TUESDAY AND WEDNESDAY.
ASIDE FROM TEMPERATURES...IT ALSO APPEARS THERE COULD BE A PERIOD
OF POSSIBLY SOME SEVERE CONVECTION SOMETIME TUESDAY NIGHT OR
WEDNESDAY. THIS WILL BE AN AREA OF FOCUS FOR THE NEXT FEW DAYS...AS
UNCERTAINTY IS TOO HIGH AT THIS STAGE TO PIN POINT THE EXTENT OF THE
SEVERE THREAT LOCALLY. HOWEVER...IT DOES APPEAR THAT THE DYNAMICS OF
THIS RAPIDLY DEVELOPING SYSTEM WILL BE SUPPORTIVE FOR STRONG
CONVECTION...FOR AREAS NOT TOO FAR TO THE NORTH OF US. THIS WOULD
ALSO INCLUDE A THREAT FOR VERY HEAVY RAINFALL GIVEN THAT PWATS WILL
LIKELY CLIMB ABOVE 1.6 INCHES IN THE WARM SECTOR OF THIS STORM
SYSTEM.
ONCE THE COLD FRONT PASSES BY LATE WEDNESDAY...COOLER AND DRIER AIR
WILL AGAIN MAKE A RETURN TO THE AREA FOR A PERIOD LATER NEXT WEEK. I
WENT WITH A DRY FORECAST FOR THURSDAY AND FRIDAY...AS IT APPEARS THE
FRONT SHOULD DROP FAR ENOUGH SOUTH OF THE AREA TO KEEP THE THREAT
FOR RAIN VERY LOW.
KJB
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 18Z...
* ORD WIND DIRECTION SOMEWHAT VARIABLE FROM NNW TO NE BUT STILL
BELIEVE PREVAILING TREND WILL FAVOR NORTHEAST QUADRANT.
* CONSIDERED LOWER VSBYS OVERNIGHT BUT AM NOT SEEING STRONG ENOUGH
SIGNALS AT THIS TIME TO INCLUDE IN TAFS.
LENNING
//DISCUSSION...UPDATED 18Z...
LOCAL EFFECTS FROM SURFACE HEATING AND THE LAKE BREEZE FORMATION
ARE PRIMARY INFLUENCES THIS AFTERNOON. HIGH PRESSURE SLIDING IN
FROM THE NORTHWEST SHOULD FURTHER REINFORCE THE LAKE BREEZE TRENDS
AND FAVOR PREVAILING NORTHEASTERLY WINDS AT ORD AND MDW. WITH SUCH
A WEAK PRESSURE GRADIENT AND DECENT MOISTURE IN THE
AREA...CONSIDERED ADDING REDUCED VSBYS OVERNIGHT. LATEST DEWPOINT
TRENDS FROM OBS AND MODELS SEEM TO BE ON THE WAY DOWN...AND
SURFACE TEMPERATURES OVERNIGHT MAY END UP BEING TOO WARM TO
SUPPORT BOUNDARY LAYER SATURATION. HIGH PRESSURE WILL AGAIN
DOMINATE TOMORROW...WITH WINDS VERY SLOWLY TURNING SOUTH OR
SOUTHEAST LATE TOMORROW EVENING.
LENNING
//ORD AND MDW CONFIDENCE...UPDATED 18Z...
* HIGH CONFIDENCE IN VFR THIS AFTERNOON AND PRIMARILY NORTHEAST
QUADRANT FOR WINDS.
LENNING
//OUTLOOK FOR ORD/MDW FOR 00Z MONDAY-12Z SATURDAY...UPDATED 12Z...
SUNDAY NIGHT...VFR.
MONDAY...CHC OF TSRA WITH MVFR CIGS POSSIBLE DURING THE AFTERNOON
AND NIGHT.
TUESDAY-WEDNESDAY...CHC OF TSRA.
THURSDAY-FRIDAY...VFR LIKELY.
MTF
&&
.MARINE...
234 AM CDT
NORTHERLY FLOW WILL PREVAIL OVER THE LAKE TODAY INTO THE DAY
SUNDAY...HELPED BY A SECONDARY COLD FRONT MOVING DOWN THE LAKE
TONIGHT. SPORADIC 20 KT GUSTS ARE POSSIBLE TODAY OVER THE LAKE BUT
MUCH OF THE TIME SHOULD REMAIN 10 TO 15 KT. HIGH PRESSURE WILL
BUILD FROM THE UPPER MIDWEST TO LAKE MI ON SUNDAY AND INTO EARLY
MONDAY...OFFERING LAKE BREEZE PUSHES IN THE NEARSHORE AREAS DURING
THE AFTERNOONS. SOUTHERLY FLOW WILL THEN ENVELOP THE LAKE AT LEAST
ON TUESDAY AND POTENTIALLY INTO WEDNESDAY AS DEEP LOW PRESSURE
TAKES SHAPE ACROSS SOUTH CENTRAL CANADA AND SWINGS A SURFACE
TROUGH EASTWARD.
MTF
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
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Area Forecast Discussion
National Weather Service Lincoln IL
1231 PM CDT Sat Aug 3 2013
.DISCUSSION...
ISSUED 956 AM CDT Sat Aug 3 2013
Cold front has settled into south-central Illinois this
morning...with latest obs showing it just south of I-70. To the
south of the front...mostly cloudy and humid conditions prevail
across southeast Illinois where dewpoints are hovering around 70
degrees. Meanwhile...a cooler/drier airmass has settled into much
of central Illinois north of the boundary...as evidenced by
14z/9am dewpoints in the upper 50s/lower 60s across the northern
KILX CWA. HRRR model suggests the potential for isolated
showers/thunder in the vicinity of the slow-moving cold front
today. No evidence is seen of this yet...as main precip event is
ongoing much further south across the Ozarks. Given high dewpoint
air and presence of boundary...will maintain slight chance POPs
south of I-70 throughout the day. Further north...made some
changes to sky cover to feature sunnier conditions. Also raised
afternoon highs by a degree or two. Zone update has already been
issued.
BARNES
&&
.AVIATION...
ISSUED 1231 PM CDT Sat Aug 3 2013
VFR conditions will prevail through the entire 18z TAF period...as
high pressure dominates the weather across central Illinois.
Latest visible satellite imagery is showing CU-field developing
mainly across the east...which matches very well with the 12z NAM
CU-rule. Will include SCT CU with bases between 3500 and
5000ft...but will carry a tempo group for BKN cloud cover at times
at both KDEC and KCMI this afternoon. Diurnal cloud cover will
fade away toward sunset...with only a few high/thin clouds
expected overnight. Winds will be northerly at less than 10kt this
afternoon...then will veer to the E/NE and remain light by Sunday
morning.
BARNES
&&
.PREV DISCUSSION...
ISSUED 330 AM CDT Sat Aug 3 2013
SHORT TERM...Today through Monday night
00z short range models are in fair agreement this weekend and then
diverge during next work week as more unsettled weather pattern
sets up across IL. Will use a blend for this forecast package with
handling weather systems during next week.
A frontal boundary was pushing southeast toward I-70 in central IN
and southeast IL into central MO early this morning. Showers have been
diminishing over east central IL past couple of hours and brought
up to half to 1 inch rains to some areas from I-74 north since Friday
evening. Cold front to push through southeast IL during this morning
and have isolated showers and thunderstorms in southeast IL
today, mainly this morning. Clouds to decrease from north to south
during the day as skies become partly to mostly sunny with northern
areas enjoying more sunshine today. Less humid air filters into
northern areas as dewpoints slip into the lower 60s while
southeast IL stays humid today with dewpoints in the upper 60s and
lower 70s. Highs in the lower 80s today with Lawrenceville around 85F.
1024 mb high pressure over Saskatchewan and western Manitoba into ND
to settle southeast into the Midwest during this weekend...and be over
northeast IL by Sunday morning. This to bring fair weather to the region
today and Sunday with mostly clear skies and more comfortable humidity
levels. Lows tonight in the mid to upper 50s and highs Sunday in the
upper 70s and lower 80s with dewpoints in the upper 50s and lower 60s.
Have slight chance of showers and thunderstorms after midnight Sunday
night over western areas due to waa pattern setting up as high pressure
drifts east of IL across the Ohio Valley. Slight chance of showers
and thunderstorms gradually spreads east across the area during Monday
and Monday night in WAA pattern.
LONG TERM...Tuesday through Saturday
A rather unsettled weather pattern expected during Tuesday through
Friday across central and southeast IL as disturbances in wnw
upper level flow track across the midwest and interact with a warmer
and more humid air mass during middle of next week. Increased temps
a few degrees Tue & Wed. Best chances of showers and thunderstorms
appears to be Tuesday night after midnight through Wed and shifting
into southern areas during Wed night and Thu as a cold front slips
southward through the region. Cooler temperatures expected later next
week with dry weather returning by weeks end on Friday night & Sat.
07
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1105 AM CDT SAT AUG 3 2013
.DISCUSSION...
339 AM CDT
THERE ARE NO BIG CONCERNS FOR THE NEXT COUPLE OF DAYS AS COOL AND
DRY HIGH PRESSURE DOMINATES ACROSS THE AREA. HOWEVER...FORECAST
CONCERNS FOR SHOWERS AND THUNDERSTORMS INCREASE AGAIN EARLY NEXT
WEEK. THEREFORE THE MAIN FORECAST CONCERNS WILL BE WITH CONVECTIVE
CHANCES AND TEMPERATURES IN THE EXTENDED.
CURRENTLY A COLD FRONT IS SAGGING SOUTHWARD ACROSS CENTRAL PORTIONS
OF ILLINOIS AND INDIANA. SHOWER AND THUNDERSTORM ACTIVITY HAS
ABATED...AND SHIFTED MOSTLY OUT OF MY AREA...WITH ONLY A FEW
LINGERING SHOWERS FAR SOUTH. OTHERWISE...SKIES ARE CLEARING ACROSS
SOUTHERN WISCONSIN AND FAR NORTHERN ILLINOIS...WITH DEW POINTS
DROPPING INTO THE LOWER 50S. THIS TREND SHOULD CONTINUE ACROSS MY
ENTIRE AREA BY MID MORNING. SURFACE HIGH PRESSURE...CENTERED OVER
NORTH DAKOTA AND INTO THE PRAIRIE PROVIDENCES OF CANADA...WILL
PRODUCE A NORTHERLY FLOW ACROSS THE AREA TODAY. TEMPERATURES LOOK TO
TOP OUT IN THE UPPER 70S TO THE LOW 80S AREA-WIDE...WITH THE
EXCEPTION OF MIDDLE 70S LAKESIDE.
TEMPERATURES TONIGHT WILL LIKELY RADIATE EFFICIENTLY WITH MOSTLY
CLEAR SKIES AND LIGHT WINDS...AS THE SURFACE HIGH DROPS
SOUTHEASTWARD ACROSS MINNESOTA AND WISCONSIN. THIS SHOULD RESULT IN
A CHILLY NIGHT...WITH TEMPERATURES FALLING INTO THE LOWER 50S AWAY
FROM CHICAGO. SUNDAY WILL ALSO BE PLEASANT WITH TEMPERATURES MAINLY
IN THE MID TO UPPER 70S.
THINGS BEGINNING TO GET MORE ACTIVE BY MONDAY AS THE SURFACE HIGH
SHIFT TO THE EAST AND ALLOWS THE LOWER LEVEL FLOW TO BECOME
SOUTHERLY AGAIN. THIS SHOULD ALLOW MOISTURE TO MAKE A QUICK RETURN
TO THE AREA. THIS IN COMBINATION WITH AN FAST AND ACTIVE
NORTHWESTERLY UPPER LEVEL LEVEL FLOW PATTERN...WILL SET THE STAGE
FOR INCREASES IN SHOWERS AND THUNDERSTORMS. IT APPEARS THE FIRST
UPPER LEVEL DISTURBANCE COULD INDUCE ENOUGH LOW LEVEL RESPONSE TO
RESULT IN SHOWERS/STORMS AS EARLY AS MONDAY. I ADDED SLIGHT CHANCE
POPS DURING THE DAY ACROSS MOST OF THE AREA TO ACCOUNT FOR THIS
POSSIBILITY.
THE NEXT AND MORE SIGNIFICANT FORECAST ISSUE WILL BE THE
SIGNIFICANT STORM SYSTEM...WHICH THE MODELS ARE SUGGESTING WILL
DEVELOP ACROSS THE UPPER MIDWEST AND INTO WESTERN ONTARIO TUESDAY
AND TUESDAY NIGHT AS A SIGNIFICANT UPPER LOW GETS DISLODGED FROM THE
HUDSON BAY REGION. THIS SYSTEM LOOKS TO SET UP A PERIOD OF POSSIBLY
SIGNIFICANT CONVECTION ACROSS THE AREA...ALONG WITH A PERIOD OF WARMER
WEATHER TUESDAY AND WEDNESDAY.
THERE ARE UNCERTAINTIES IN THE FINNER SCALE DETAILS OF THIS SYSTEM.
HOWEVER...IT DOES APPEAR THAT WARMER CONDITIONS WILL SET UP FOR
TUESDAY...AND POTENTIAL INTO WEDNESDAY AS WELL AS SOUTHERLY FLOW
AHEAD OF THE DEVELOPING LOW...WILL RESULT IN AN INFLUX OF A
WARMER...MORE HUMID AIRMASS. THE MODEL GUIDANCE APPEARS TO BE
UNDERDOING THE WARM FOR TUESDAY AND POSSIBLY WEDNESDAY AS WELL.
ALTHOUGH THERE WILL BE PERIOD OF CONVECTION AROUND...IT APPEARS
TUESDAY LOOKS TO BE A GOOD CANDIDATE FOR TEMPERATURES TOPPING OUT
IN THE MID TO UPPER 80S...AS 850 AND 925 MB TEMPERATURES ARE
PROGGED TO BE AROUND 18 AND 22 DEGREES C...RESPECTIVELY.
TEMPERATURES ON WEDNESDAY COULD BE JUST AS WARM.
HOWEVER...DIFFERENCES AND UNCERTAINTIES ON THE EXACT TIMING OF THE
COLD FRONTAL PASSAGE ON WEDNESDAY COULD COMPLICATE THINGS. IN
SPITE OF THIS...I DID WARM TEMPERATURES INTO THE LOW TO MID 80S
FOR BOTH TUESDAY AND WEDNESDAY.
ASIDE FROM TEMPERATURES...IT ALSO APPEARS THERE COULD BE A PERIOD
OF POSSIBLY SOME SEVERE CONVECTION SOMETIME TUESDAY NIGHT OR
WEDNESDAY. THIS WILL BE AN AREA OF FOCUS FOR THE NEXT FEW DAYS...AS
UNCERTAINTY IS TOO HIGH AT THIS STAGE TO PIN POINT THE EXTENT OF THE
SEVERE THREAT LOCALLY. HOWEVER...IT DOES APPEAR THAT THE DYNAMICS OF
THIS RAPIDLY DEVELOPING SYSTEM WILL BE SUPPORTIVE FOR STRONG
CONVECTION...FOR AREAS NOT TOO FAR TO THE NORTH OF US. THIS WOULD
ALSO INCLUDE A THREAT FOR VERY HEAVY RAINFALL GIVEN THAT PWATS WILL
LIKELY CLIMB ABOVE 1.6 INCHES IN THE WARM SECTOR OF THIS STORM
SYSTEM.
ONCE THE COLD FRONT PASSES BY LATE WEDNESDAY...COOLER AND DRIER AIR
WILL AGAIN MAKE A RETURN TO THE AREA FOR A PERIOD LATER NEXT WEEK. I
WENT WITH A DRY FORECAST FOR THURSDAY AND FRIDAY...AS IT APPEARS THE
FRONT SHOULD DROP FAR ENOUGH SOUTH OF THE AREA TO KEEP THE THREAT
FOR RAIN VERY LOW.
KJB
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 16Z...
* NO MAJOR CONCERNS THIS AFTERNOON/EVENING.
* SOME UNCERTAINTY WHETHER GUSTS WILL DEVELOP...BUT ONLY WOULD
EXPECT MID TEENS.
* ALSO SOME UNCERTAINTY REGARDING CEILINGS...BUT LIKELY TO STAY
SCATTERED AND CERTAINLY VFR.
LENNING
//DISCUSSION...UPDATED 12Z...
HIGH PRESSURE WILL CONTINUE TO EXPAND FROM THE UPPER MIDWEST INTO
THE WESTERN GREAT LAKES TODAY BEHIND A DEPARTING COOL FRONT. THE
ORIENTATION OF THE HIGH WILL FAVOR NORTHERLY WINDS TO BECOME MORE
NORTHEASTERLY ACROSS CHICAGOLAND LATE THIS MORNING AND INTO THE
AFTERNOON...AND EVEN MORE PRONOUNCED TO POTENTIALLY ENE GIVEN THE
LAKE ORIENTATION AND CLIMATOLOGY OF SUCH FLOW. THE SPEEDS WILL
LIKELY APPROACH 10 KT AND HOLD AS SUCH THROUGH THE AFTERNOON. A
WEAK SECONDARY FRONT WILL DROP SOUTH THROUGH THE REGION TONIGHT
AND THAT COULD KEEP A LIGHT NORTHERLY COMPONENT. IF NOT
THOUGH...PATCHY FOG DEVELOPMENT MAY BE SEEN AS IT WAS THIS MORNING
ACROSS THE REGION...ESPECIALLY AT FAVORED LOW-LYING OPEN AIRPORTS.
HIGH PRESSURE ON SUNDAY WILL ALLOW FOR AN EVEN MORE PRONOUNCED LAKE
PUSH.
//ORD AND MDW CONFIDENCE...UPDATED 16Z...
* MEDIUM TO HIGH CONFIDENCE IN ALL ELEMENTS.
LENNING
//OUTLOOK FOR ORD/MDW FOR 00Z MONDAY-12Z SATURDAY...UPDATED 12Z...
SUNDAY NIGHT...VFR.
MONDAY...CHC OF TSRA WITH MVFR CIGS POSSIBLE DURING THE AFTERNOON
AND NIGHT.
TUESDAY-WEDNESDAY...CHC OF TSRA.
THURSDAY-FRIDAY...VFR LIKELY.
MTF
&&
.MARINE...
234 AM CDT
NORTHERLY FLOW WILL PREVAIL OVER THE LAKE TODAY INTO THE DAY
SUNDAY...HELPED BY A SECONDARY COLD FRONT MOVING DOWN THE LAKE
TONIGHT. SPORADIC 20 KT GUSTS ARE POSSIBLE TODAY OVER THE LAKE BUT
MUCH OF THE TIME SHOULD REMAIN 10 TO 15 KT. HIGH PRESSURE WILL
BUILD FROM THE UPPER MIDWEST TO LAKE MI ON SUNDAY AND INTO EARLY
MONDAY...OFFERING LAKE BREEZE PUSHES IN THE NEARSHORE AREAS DURING
THE AFTERNOONS. SOUTHERLY FLOW WILL THEN ENVELOP THE LAKE AT LEAST
ON TUESDAY AND POTENTIALLY INTO WEDNESDAY AS DEEP LOW PRESSURE
TAKES SHAPE ACROSS SOUTH CENTRAL CANADA AND SWINGS A SURFACE
TROUGH EASTWARD.
MTF
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
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Area Forecast Discussion
National Weather Service Lincoln IL
956 AM CDT Sat Aug 3 2013
.DISCUSSION...
ISSUED 956 AM CDT Sat Aug 3 2013
Cold front has settled into south-central Illinois this
morning...with latest obs showing it just south of I-70. To the
south of the front...mostly cloudy and humid conditions prevail
across southeast Illinois where dewpoints are hovering around 70
degrees. Meanwhile...a cooler/drier airmass has settled into much
of central Illinois north of the boundary...as evidenced by
14z/9am dewpoints in the upper 50s/lower 60s across the northern
KILX CWA. HRRR model suggests the potential for isolated
showers/thunder in the vicinity of the slow-moving cold front
today. No evidence is seen of this yet...as main precip event is
ongoing much further south across the Ozarks. Given high dewpoint
air and presence of boundary...will maintain slight chance POPs
south of I-70 throughout the day. Further north...made some
changes to sky cover to feature sunnier conditions. Also raised
afternoon highs by a degree or two. Zone update has already been
issued.
BARNES
&&
.AVIATION...
ISSUED 640 AM CDT Sat Aug 3 2013
The showers associated with the cold front have advanced east of
all the terminal sites, so no mention of precip is in any of the
tafs. We did add some mvfr fog to KSPI, but none of the other taf
sites were experiencing fog, nor are expected to this morning.
Weak high pressure advancing into central IL behind the front will
help to clear out low clouds, and provide light north-northeast
winds. High cirrus clouds from a storm complex in Missouri will
cover our area this morning, but mostly sunny skies should develop
by afternoon.
Forecast soundings are not strong on fog indicators for late
tonight, so we did not include any mention of fog at the end of
this taf period.
SHIMON
&&
.PREV DISCUSSION...
ISSUED 330 AM CDT Sat Aug 3 2013
SHORT TERM...Today through Monday night
00z short range models are in fair agreement this weekend and then
diverge during next work week as more unsettled weather pattern
sets up across IL. Will use a blend for this forecast package with
handling weather systems during next week.
A frontal boundary was pushing southeast toward I-70 in central IN
and southeast IL into central MO early this morning. Showers have been
diminishing over east central IL past couple of hours and brought
up to half to 1 inch rains to some areas from I-74 north since Friday
evening. Cold front to push through southeast IL during this morning
and have isolated showers and thunderstorms in southeast IL
today, mainly this morning. Clouds to decrease from north to south
during the day as skies become partly to mostly sunny with northern
areas enjoying more sunshine today. Less humid air filters into
northern areas as dewpoints slip into the lower 60s while
southeast IL stays humid today with dewpoints in the upper 60s and
lower 70s. Highs in the lower 80s today with Lawrenceville around 85F.
1024 mb high pressure over Saskatchewan and western Manitoba into ND
to settle southeast into the Midwest during this weekend...and be over
northeast IL by Sunday morning. This to bring fair weather to the region
today and Sunday with mostly clear skies and more comfortable humidity
levels. Lows tonight in the mid to upper 50s and highs Sunday in the
upper 70s and lower 80s with dewpoints in the upper 50s and lower 60s.
Have slight chance of showers and thunderstorms after midnight Sunday
night over western areas due to waa pattern setting up as high pressure
drifts east of IL across the Ohio Valley. Slight chance of showers
and thunderstorms gradually spreads east across the area during Monday
and Monday night in WAA pattern.
LONG TERM...Tuesday through Saturday
A rather unsettled weather pattern expected during Tuesday through
Friday across central and southeast IL as disturbances in wnw
upper level flow track across the midwest and interact with a warmer
and more humid air mass during middle of next week. Increased temps
a few degrees Tue & Wed. Best chances of showers and thunderstorms
appears to be Tuesday night after midnight through Wed and shifting
into southern areas during Wed night and Thu as a cold front slips
southward through the region. Cooler temperatures expected later next
week with dry weather returning by weeks end on Friday night & Sat.
07
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS DULUTH MN
1255 PM CDT SAT AUG 3 2013
.AVIATION...18Z TAF ISSUANCE.
BUILDING HIGH PRESSURE FROM THE DAKOTAS WILL RESULT IN NORTHWEST
WINDS...WITH OCCASIONAL GUSTS TO 20 KT...THROUGH THE AFTERNOON.
VFR CONDITIONS WILL PREVAIL THROUGH THE TAF PERIOD WITH SCT-BKN
CU THIS AFTERNOON RANGING FROM 5-8 KFT. WINDS WILL BECOMING LIGHT
WITH DECREASING CLOUDS AFTER 00Z. THE SFC RIDGE WILL MOVE INTO THE
NORTHLAND OVERNIGHT...ALLOWING FOR STRONG RADIATIONAL COOLING AND
A POTENTIAL FOR A FEW HOUR WINDOW OF PATCHY BR/FG.
&&
.PREV DISCUSSION... /ISSUED 1136 AM CDT SAT AUG 3 2013/
UPDATE...LOOKS LIKE A PARTLY CLOUDY DAY ACROSS THE NORTHLAND WITH
PARTLY CLOUDY CUMULUS FOR THE REST OF THE DAY. TEMPS WILL CONTINUE
TO RISE INTO THE 70S FOR MOST AREAS WITH NORTHERLY WINDS.
PREV DISCUSSION... /ISSUED 303 AM CDT SAT AUG 3 2013/
SHORT TERM.../THROUGH TONIGHT/
AT 300AM/0800Z...SURFACE HIGH PRESSURE WAS CENTERED OVER CENTRAL
SASKATCHEWAN AND MANITOBA. THE AXIS OF A MID/UPPER LEVEL RIDGE
STRETCHED ACROSS THE WESTERN PLAINS. A SHORTWAVE NEAR THE
MONTANA/NORTH DAKOTA BORDER WAS MOVING EAST AS IT ROUNDED THE
RIDGE...AND IT WAS BRINGING BKN/OVC MID/UPPER LEVEL CLOUDS ACROSS
NORTH DAKOTA INTO NORTHERN MINNESOTA. A MID/UPPER LEVEL LOW WAS
NEAR SW HUDSON BAY. BKN/OVC LOW CLOUDS COVERED MUCH OF NORTHERN
ONTARIO...BUT WERE SLOWLY APPROACHING THE CANADA/MINNESOTA BORDER.
MOST OF THE NORTHLAND HAD CLEAR SKIES EXCEPT FOR THE WESTERN
FORECAST AREA DUE TO THE FEW/SCT MID/UPPER LEVEL CLOUDS ASSOCIATED
WITH THE APPROACHING SHORTWAVE BEGINNING WORKING THEIR WAY INTO
THE NORTHLAND. THE SURFACE WINDS WERE NEARLY CALM OR VERY LIGHT
FROM THE WNW. TEMPERATURES RANGED FROM THE MID 40S TO LOW 50S.
TODAY...THE CENTER OF THE SURFACE HIGH PRESSURE IN CANADA WILL
MOVE INTO THE RED RIVER VALLEY REGION BY LATE THIS AFTERNOON. THE
NORTHLAND CAN EXPECT PARTLY SUNNY SKIES. THERE WILL BE SOME
MID/UPPER LEVEL CLOUDS ASSOCIATED WITH THE SHORTWAVE IN NORTH
DAKOTA THAT WILL CUT ACROSS NORTHERN MINNESOTA THIS MORNING...AS
WELL AS SCATTERED CUMULUS THAT WILL DEVELOP BY LATE THIS MORNING
DUE TO THE LOW CONVECTIVE TEMPERATURES IN THE COOL NW FLOW. HIGH
TEMPERATURES SHOULD RANGE FROM THE UPPER 60S TO MID 70S.
TONIGHT...THE CENTER OF THE HIGH PRESSURE SYSTEM WILL MOVE THROUGH
THE NORTHLAND. THIS WILL BRING CALM WINDS AND CLEAR SKIES TO THE
REGION. THERE COULD BE PATCHY FOG...BUT SINCE THE SOUNDINGS AND
MODEL FORECAST SURFACE CONDENSATION PRESSURE DEFICITS DO NOT
PROVIDE ENOUGH SUGGESTION OF FOG...I LEFT IT OUT OF THE FORECAST
AT THIS POINT. THE DAY SHIFT MAY NEED TO ADD PATCHY FOG TO THE
FORECAST. OVERNIGHT LOWS SHOULD BE IN THE LOW TO UPPER 40S ACROSS
MOST OF THE REGION. I WOULD NOT BE SURPRISED IF ISOLATED LOCATIONS
ACROSS NORTHERN MINNESOTA GET INTO THE UPPER 30S.
LONG TERM.../SUNDAY - FRIDAY/
THE AREA OF HIGH PRESSURE WILL
BRING ANOTHER DAY OF QUIET CONDITIONS ACROSS THE REGION ON SUNDAY.
THE NEXT SHOT OF PRECIPITATION WILL COME MONDAY THROUGH TUESDAY
WHEN A LOW PRESSURE CENTER MOVES THROUGH SOUTHERN CANADA ALONG
WITH A SHORTWAVE THAT MOVE THROUGH NRN MN MONDAY AND TUESDAY
MORNING WHICH WILL BRING SHOWERS AND THUNDERSTORMS TO THE FORECAST
AREA. THERE WILL BE BREAK TUESDAY MORNING BEFORE THE LOW DRAGS A
FRONT THROUGH THE REGION TUESDAY AFTERNOON AND EVENING BRINGING
ANOTHER CHANCE FOR THUNDERSTORMS. AFTER THE FRONT PASSES...COOLER
THAN NORMAL TEMPS WILL FLOW INTO THE REGION FOR THE REST OF THE
WEEK WITH LITTLE PRECIPITATION EXPECTED THROUGH THE PERIOD.
AVIATION.../06Z TAF ISSUANCE/
MAINLY VFR CONDITIONS WILL OCCUR THROUGH THE PERIOD. THERE MAY BE
SOME PATCHY FOG TONIGHT WITH VSBYS DROPPING TO IFR...AND WE HAVE
THAT IN THE KBRD/KHIB/KHYR TAFS ATTM. BROKEN CEILINGS FROM 5-8KFT
WILL BE POSSIBLE OVER THE ARROWHEAD AND BORDER REGION
TONIGHT...BUT BOTH THE RAP AND NAM SUGGEST IT WILL BE MOSTLY
SCATTERED BY LATE TONIGHT. WE EXPECT MORE SCATTERED TO BROKEN VFR
CUMULUS TO FORM ON SATURDAY WITH SOME HEATING.
&&
.POINT TEMPS/POPS...
DLH 50 74 50 71 / 0 10 10 20
INL 42 72 49 73 / 0 10 10 10
BRD 49 75 57 74 / 0 10 30 30
HYR 44 73 52 72 / 0 10 10 30
ASX 47 74 51 70 / 0 10 10 20
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
LS...NONE.
&&
$$
AVIATION...GRANING
AREA FORECAST DISCUSSION
NWS DULUTH MN
1136 AM CDT SAT AUG 3 2013
.UPDATE...LOOKS LIKE A PARTLY CLOUDY DAY ACROSS THE NORTHLAND WITH
PARTLY CLOUDY CUMULUS FOR THE REST OF THE DAY. TEMPS WILL CONTINUE
TO RISE INTO THE 70S FOR MOST AREAS WITH NORTHERLY WINDS.
&&
.PREV DISCUSSION... /ISSUED 653 AM CDT SAT AUG 3 2013/
AVIATION...12Z TAFS...LIFR-IFR CIGS/VSBYS IN FOG WILL IMPROVE TO
VFR CONDTIONS BY MID-MORNING. ELSEWHERE...AN AREA OF HIGH PRESSURE
WILL DOMINATE THE WEATHER THROUGH SUNDAY. VFR CONDTIONS WILL BE
ALL ALL SITES THROUGH SUNDAY AFTERNOON. THERE MAY BE SOME MVFR
VSBYS IN FOG AT SOME STIES EARLY SUNDAY MORNING.
PREV DISCUSSION... /ISSUED 303 AM CDT SAT AUG 3 2013/
SHORT TERM.../THROUGH TONIGHT/
AT 300AM/0800Z...SURFACE HIGH PRESSURE WAS CENTERED OVER CENTRAL
SASKATCHEWAN AND MANITOBA. THE AXIS OF A MID/UPPER LEVEL RIDGE
STRETCHED ACROSS THE WESTERN PLAINS. A SHORTWAVE NEAR THE
MONTANA/NORTH DAKOTA BORDER WAS MOVING EAST AS IT ROUNDED THE
RIDGE...AND IT WAS BRINGING BKN/OVC MID/UPPER LEVEL CLOUDS ACROSS
NORTH DAKOTA INTO NORTHERN MINNESOTA. A MID/UPPER LEVEL LOW WAS
NEAR SW HUDSON BAY. BKN/OVC LOW CLOUDS COVERED MUCH OF NORTHERN
ONTARIO...BUT WERE SLOWLY APPROACHING THE CANADA/MINNESOTA BORDER.
MOST OF THE NORTHLAND HAD CLEAR SKIES EXCEPT FOR THE WESTERN
FORECAST AREA DUE TO THE FEW/SCT MID/UPPER LEVEL CLOUDS ASSOCIATED
WITH THE APPROACHING SHORTWAVE BEGINNING WORKING THEIR WAY INTO
THE NORTHLAND. THE SURFACE WINDS WERE NEARLY CALM OR VERY LIGHT
FROM THE WNW. TEMPERATURES RANGED FROM THE MID 40S TO LOW 50S.
TODAY...THE CENTER OF THE SURFACE HIGH PRESSURE IN CANADA WILL
MOVE INTO THE RED RIVER VALLEY REGION BY LATE THIS AFTERNOON. THE
NORTHLAND CAN EXPECT PARTLY SUNNY SKIES. THERE WILL BE SOME
MID/UPPER LEVEL CLOUDS ASSOCIATED WITH THE SHORTWAVE IN NORTH
DAKOTA THAT WILL CUT ACROSS NORTHERN MINNESOTA THIS MORNING...AS
WELL AS SCATTERED CUMULUS THAT WILL DEVELOP BY LATE THIS MORNING
DUE TO THE LOW CONVECTIVE TEMPERATURES IN THE COOL NW FLOW. HIGH
TEMPERATURES SHOULD RANGE FROM THE UPPER 60S TO MID 70S.
TONIGHT...THE CENTER OF THE HIGH PRESSURE SYSTEM WILL MOVE THROUGH
THE NORTHLAND. THIS WILL BRING CALM WINDS AND CLEAR SKIES TO THE
REGION. THERE COULD BE PATCHY FOG...BUT SINCE THE SOUNDINGS AND
MODEL FORECAST SURFACE CONDENSATION PRESSURE DEFICITS DO NOT
PROVIDE ENOUGH SUGGESTION OF FOG...I LEFT IT OUT OF THE FORECAST
AT THIS POINT. THE DAY SHIFT MAY NEED TO ADD PATCHY FOG TO THE
FORECAST. OVERNIGHT LOWS SHOULD BE IN THE LOW TO UPPER 40S ACROSS
MOST OF THE REGION. I WOULD NOT BE SURPRISED IF ISOLATED LOCATIONS
ACROSS NORTHERN MINNESOTA GET INTO THE UPPER 30S.
LONG TERM.../SUNDAY - FRIDAY/
THE AREA OF HIGH PRESSURE WILL
BRING ANOTHER DAY OF QUIET CONDITIONS ACROSS THE REGION ON SUNDAY.
THE NEXT SHOT OF PRECIPITATION WILL COME MONDAY THROUGH TUESDAY
WHEN A LOW PRESSURE CENTER MOVES THROUGH SOUTHERN CANADA ALONG
WITH A SHORTWAVE THAT MOVE THROUGH NRN MN MONDAY AND TUESDAY
MORNING WHICH WILL BRING SHOWERS AND THUNDERSTORMS TO THE FORECAST
AREA. THERE WILL BE BREAK TUESDAY MORNING BEFORE THE LOW DRAGS A
FRONT THROUGH THE REGION TUESDAY AFTERNOON AND EVENING BRINGING
ANOTHER CHANCE FOR THUNDERSTORMS. AFTER THE FRONT PASSES...COOLER
THAN NORMAL TEMPS WILL FLOW INTO THE REGION FOR THE REST OF THE
WEEK WITH LITTLE PRECIPITATION EXPECTED THROUGH THE PERIOD.
AVIATION.../06Z TAF ISSUANCE/
MAINLY VFR CONDITIONS WILL OCCUR THROUGH THE PERIOD. THERE MAY BE
SOME PATCHY FOG TONIGHT WITH VSBYS DROPPING TO IFR...AND WE HAVE
THAT IN THE KBRD/KHIB/KHYR TAFS ATTM. BROKEN CEILINGS FROM 5-8KFT
WILL BE POSSIBLE OVER THE ARROWHEAD AND BORDER REGION
TONIGHT...BUT BOTH THE RAP AND NAM SUGGEST IT WILL BE MOSTLY
SCATTERED BY LATE TONIGHT. WE EXPECT MORE SCATTERED TO BROKEN VFR
CUMULUS TO FORM ON SATURDAY WITH SOME HEATING.
&&
.POINT TEMPS/POPS...
DLH 72 50 74 50 / 0 0 10 10
INL 69 42 72 49 / 0 0 10 10
BRD 74 49 75 57 / 0 0 10 30
HYR 73 44 73 52 / 0 0 10 10
ASX 73 47 74 51 / 0 0 10 10
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
LS...NONE.
&&
$$
SHORT TERM...DAP
LONG TERM....GRANING
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
302 PM EDT SAT AUG 3 2013
.SYNOPSIS...
ISOLATED SHOWERS WILL DIMINISH TONIGHT WITH FAIR BUT CHILLY
WEATHER EXPECTED. A COOL HIGH PRESSURE SYSTEM WILL BUILD INTO
GREAT LAKES AND OHIO VALLEY REGION SUNDAY WITH A FEW LAKE EFFECT
RAIN SHOWERS AFFECTING MAINLY CENTRAL NEW YORK. THIS HIGH PRESSURE
SYSTEM WILL BUILD FARTHER EAST AND COVER THE REGION FROM SUNDAY
NIGHT THROUGH MONDAY NIGHT WITH FAIR WEATHER DURING THE DAY AND
FAIRLY CHILLY TEMPERATURES BOTH SUNDAY NIGHT AND MONDAY NIGHT.
VALLEY FOG WILL BE PREVALENT BOTH NIGHTS. THE NEXT CHANCE FOR A
LITTLE RAIN WILL COME ON TUESDAY BUT IT WILL BE WIDELY SCATTERED.
MOST OF TUESDAY SHOULD BE FAIRLY DRY AND MILDER AS THE HIGH
PRESSURE SYSTEM MOVES OFFSHORE AND A SOUTHERLY RETURN FLOW
DEVELOPS.
&&
.NEAR TERM /THROUGH SUNDAY/...
RADAR WAS LARGELY FREE OF ECHOES EARLY THIS AFTERNOON EXCEPT FOR A
FEW VERY ISLD SHRA OCCASIONALLY POPPING UP HERE AND THERE BUT
BEING SHORT-LIVED. ACVTY SEEMS TO BE A TAD MORE PREVALENT IN NE
PA NR SFC FRNT WHICH EXTENDED FROM NRN CATSKILLS TO BTWN IPT AND
AVP IN NE PA IN OUR FORECAST AREA. WATER VAPOR IMAGERY SHOWS
SIGNIFICANT UPPER LEVEL WAVE MOVG ACRS NRN NEW ENGLAND AND SERN
CANADA. THIS WAVE WAS ENHANCING STRG UPR CONFLUENCE ACRS NEW
ENGLAND TO NOVA SCOTIA AND HENCE AN UPPER LEVEL JET STREAK WAS
POSITIONED IN THIS AREA. ENHANCED DVRG IN THE RR QUAD OF THE JET
WAS PROMOTING SOME LIFTING INTO NE PA AND ITS LOWER LEVEL AGEO
FORCING WAS ALSO PUSH THE FRNT SOUTHWARD. BEST SHOT OF A FEW SHRA
AND EVEN A LITTLE TSRA WILL BE MAINLY ACRS OUR FAR SE FORECAST
AREA IN THE POCONOS TO SRN CATSKILLS FOR THE REST OF THE
AFTERNOON DUE TO THIS DYNAMICAL FORCING. NORTH OF THE FRNT...THE
CUMULUS WAS BUILDING BUT NOT TO EXTENT THAT I EARLIER THHOUGHT.
THE ONLY EXCEPTION WAS OVER AREAS DIRECTLY DOWNWIND OF LAKE
ONTARIO WHERE LAKE MOISTURE WAS ENHANCING LL MOISTURE AND LEADING
TO DEEPER CUMULUS AND A LITTLE ISLD SHRA ACVTY AT TIMES. HENCE
HAVE SOME ISLD CHC OF SHRA WELL N OF THE FRNT ACRS CNTRL NY AND
NRN PA. THIS ACVTY WILL WANE SOON EXCEPT IN NC NY DOWNWIND OF LAKE
ONTARIO.
FOR TONIGHT...INITIALLY CUMULUS AND ISLD SHRA WILL FALL APART WITH
LOSS OF INSOLATION. CONTINUED LL NW FLOW AND CAA WILL CONT ACRS
THE RELATIVELY WARM WATERS OF LAKE ONTARIO. LAKE ONTARIO TEMPS
WERE RUNNING ARND 20-21C AS 850 MB TEMPS DROP TO ARND 7-8C OR SO BY
LATE TONIGHT. ADDTNLY ANOTHER SHRT WAVE WILL DROP SOUTHWARD
OVERNIGHT REACHING SOUTHEAST ONTARIO AND WESTERN QUEBEC BY 12Z.
LIFTING FROM THIS WAVE IN ASSCTN WITH LAKE MOISTURE WILL TRIGGER
SHRA AGAIN LATER TONIGHT IN NC NY...WITH NO PRECIPITATION EXPECTED
IN SC NY DOWN TO NE PA BEFORE 12Z.
THEN FOR SUNDAY...UPPER LEVEL WAVE PASSES TO THE EAST BUT IS
FOLLOWING BY AN EVEN CHILLIER SHOT OF AIR WITH 850 MB TEMPS
DROPPING TO ARND 6C WHICH IS ABT A 14-15C DIFFERENTIAL. THE FLOW
REMAINS ABT 310 OR SO WHICH WILL BRING LAKE MOISTURE DOWN INTO THE
HILLS OF NC NY AND DOWN TO SC NY AND FAR NE PA. WITH INSOLATION
AND COLD TEMPERATURES AT 850 MB I SEE ISLD TO SCT SHRA FROM NRN PA
TO SC NY AND SCT SHRA INTO NC NY DIRECTLY DOWNWIND OF LAKE
ONTARIO. THE ACVTY WILL WANE LATER IN THE DAY AS INSOLATION BREAKS
UP ANY ORGANIZED LAKE EFFECT RAINS. HAVE SLGHT CHC IN NE PA TO LO
CHC IN SC NY TO HIGH CHC IN NC NY FOR SUNDAY.
&&
.SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY/...
HIGH PRESSURE WILL BUILD OVER THE REGION SUNDAY NIGHT AND CROSS
THE REGION MONDAY AND MONDAY NIGHT WITH FAIR WEATHER. WITH LIGHT
WINDS I EXPECT PLENTY OF VALLEY FOG LATE SUNDAY NIGHT AND LATE
MONDAY NIGHT. FOR TUESDAY A WARM FRONT AND SOUTHERLY RETURN FLOW
WILL LIKELY SPREAD A FEW SHRA INTO NE PA AND C NY. THE
CMC...EURO...GFS AND NAM ALL INDICATE TO VARYING DEGREES THAT
THERE WILL BE ENUF MOISTURE ADVECTION FOR SOME PATCHY SHRA ACTVY.
I WENT SLGHT CHC FOR NOW FOR SHRA. OTHERWISE...FAIRLY QUIET ON
TUESDAY AND A LITTLE MILDER.
&&
.LONG TERM /TUESDAY NIGHT THROUGH FRIDAY/...
RISING HGTS ON TUE WILL RESULT IN SOME INCRSG CLDS BUT SHWRS SHD
BE LIMITED DUE TO STUBBORN LL DRY AIR. YET ANOTHER DIGGING LOW
APCHS FOR WED AND THU AND PUSHES A SFC BNDRY THRU THE AREA. GOOD
GULF CONNECTIONS SHD LEAD TO GOOD CVRG OF SHWRS AND TRWS LATE WED
INTO THU AHD OF THE TROF. DRIER AND COOLER AIR RETURNS ON FRI BHD
THE FNT. ATTM IT LOOKS DRY BHD THE FNT BUT EVENTUALLY THE LWRG
HGTS WITH THE LRG UA LOW WILL RESULT IN MAINLY AFTN CONV.
TEMPS WILL CONT TO AVG WELL BLO SEASONAL NORMS THRU THE PD. MEX
GUID WAS RUNNING A BIT HIER THRU THE PD THAN HPC BUT SEEMED LIKE
THE COOLER EURO HAD A BETTER HANDLE ON THE UA LOW SO MORE CLOSELY
FLWD HPC GUID.
&&
.AVIATION /19Z SATURDAY THROUGH THURSDAY/...
MUCH DRIER AIR CONTS TO STREAM INTO THE AREA BRINGING VFR CIGS AND
VSBYS. SHRT WV DROPPING INTO THE UPR TROF WILL RETURN MVFR CIGS
LATE TNGT AS THE WV GRABS MOISTURE OFF THE LAKES. OCNL SHRA OVER
THE RME AND SYR PSBL AFT 08Z SHD NOT LIMT THE VSBYS. MVFR/VFR CIGS
WILL CONT THRU THE END OF THE TAF PD WITH A CAA NW FLOW REGIME.
WINDS WILL BE COME LGT TNGT...THEN NW ONCE AGAIN ON SUN WITH
MIXING.
MON THRU WED...MAINLY VFR.
THU...MVFR IN SHRA AND TSRA.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...DJN
NEAR TERM...DJN
SHORT TERM...DJN
LONG TERM...DGM
AVIATION...DGM
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
203 PM EDT SAT AUG 3 2013
.SYNOPSIS...
A COLD FRONT WILL GRADUALLY CROSS THE REGION THIS AFTERNOON.
ALTHOUGH A FEW SHOWERS WILL PRECEDE THIS SYSTEM...MUCH OF THE DAY
IS EXPECTED TO BE RAIN FREE. A COOLER NORTHWEST AIR FLOW WILL
FOLLOW FOR THE SECOND HALF OF THE WEEKEND...ALONG WITH A FEW HIT
AND MISS SHOWERS ON SUNDAY...MAINLY OVER CENTRAL NEW YORK.
&&
.NEAR TERM /THROUGH SUNDAY/...
RADAR WAS LARGELY FREE OF ECHOES EARLY THIS AFTERNOON EXCEPT FOR A
FEW VERY ISLD SHRA OCCASIONALLY POPPING UP HERE AND THERE BUT
BEING SHORT-LIVED. ACVTY SEEMS TO BE A TAD MORE PREVALENT IN NE
PA NR SFC FRNT WHICH EXTENDED FROM NRN CATSKILLS TO BTWN IPT AND
AVP IN NE PA IN OUR FORECAST AREA. WATER VAPOR IMAGERY SHOWS
SIGNIFICANT UPPER LEVEL WAVE MOVG ACRS NRN NEW ENGLAND AND SERN
CANADA. THIS WAVE WAS ENHANCING STRG UPR CONFLUENCE ACRS NEW
ENGLAND TO NOVA SCOTIA AND HENCE AN UPPER LEVEL JET STREAK WAS
POSITIONED IN THIS AREA. ENHANCED DVRG IN THE RR QUAD OF THE JET
WAS PROMOTING SOME LIFTING INTO NE PA AND ITS LOWER LEVEL AGEO
FORCING WAS ALSO PUSH THE FRNT SOUTHWARD. BEST SHOT OF A FEW SHRA
AND EVEN A LITTLE TSRA WILL BE MAINLY ACRS OUR FAR SE FORECAST
AREA IN THE POCONOS TO SRN CATSKILLS FOR THE REST OF THE
AFTERNOON DUE TO THIS DYNAMICAL FORCING. NORTH OF THE FRNT...THE
CUMULUS WAS BUILDING BUT NOT TO EXTENT THAT I EARLIER THHOUGHT.
THE ONLY EXCEPTION WAS OVER AREAS DIRECTLY DOWNWIND OF LAKE
ONTARIO WHERE LAKE MOISTURE WAS ENHANCING LL MOISTURE AND LEADING
TO DEEPER CUMULUS AND A LITTLE ISLD SHRA ACVTY AT TIMES. HENCE
HAVE SOME ISLD CHC OF SHRA WELL N OF THE FRNT ACRS CNTRL NY AND
NRN PA. THIS ACVTY WILL WANE SOON EXCEPT IN NC NY DOWNWIND OF LAKE
ONTARIO.
FOR TONIGHT...INITIALLY CUMULUS AND ISLD SHRA WILL FALL APART WITH
LOSS OF INSOLATION. CONTINUED LL NW FLOW AND CAA WILL CONT ACRS
THE RELATIVELY WARM WATERS OF LAKE ONTARIO. LAKE ONTARIO TEMPS
WERE RUNNING ARND 20-21C AS 850 MB TEMPS DROP TO ARND 7-8C OR SO BY
LATE TONIGHT. ADDTNLY ANOTHER SHRT WAVE WILL DROP SOUTHWARD
OVERNIGHT REACHING SOUTHEAST ONTARIO AND WESTERN QUEBEC BY 12Z.
LIFTING FROM THIS WAVE IN ASSCTN WITH LAKE MOISTURE WILL TRIGGER
SHRA AGAIN LATER TONIGHT IN NC NY...WITH NO PRECIPITATION EXPECTED
IN SC NY DOWN TO NE PA BEFORE 12Z.
THEN FOR SUNDAY...UPPER LEVEL WAVE PASSES TO THE EAST BUT IS
FOLLOWING BY AN EVEN CHILLIER SHOT OF AIR WITH 850 MB TEMPS
DROPPING TO ARND 6C WHICH IS ABT A 14-15C DIFFERENTIAL. THE FLOW
REMAINS ABT 310 OR SO WHICH WILL BRING LAKE MOISTURE DOWN INTO THE
HILLS OF NC NY AND DOWN TO SC NY AND FAR NE PA. WITH INSOLATION
AND COLD TEMPERATURES AT 850 MB I SEE ISLD TO SCT SHRA FROM NRN PA
TO SC NY AND SCT SHRA INTO NC NY DIRECTLY DOWNWIND OF LAKE
ONTARIO. THE ACVTY WILL WANE LATER IN THE DAY AS INSOLATION BREAKS
UP ANY ORGANIZED LAKE EFFECT RAINS. HAVE SLGHT CHC IN NE PA TO LO
CHC IN SC NY TO HIGH CHC IN NC NY FOR SUNDAY.
&&
.SHORT TERM /SUNDAY NIGHT THROUGH MONDAY NIGHT/...
5 AM UPDATE... DEEPENING NW FLOW TNT-SUN...AS THE MAIN UPR LVL
TROUGH AXIS SHIFTS INTO QUE...WILL ALLOW A COOLER AMS TO SPREAD
INTO NY/PA. LINGERING LOW LVL MOISTURE WILL COMBINE WITH THE
PASSAGE OF ANOTHER S/WV LATE TNT INTO SUN...TO BRING SCTD -SHRA
ACRS OUR CNY ZNS...ALSO HELPED BY SOME UPSLOPING VIA NWLY FLOW.
925-850 MB CAA ON SUN...ALG WITH AT LEAST MRNG CLDNS/SCTD
-SHRA...WILL BRING COOLER READINGS (AS MENTIONED ABV)...WITH HIGH
TEMPS PERHAPS STAYING IN THE UPR 60S FOR SXNS OF THE FA (SPCLY THE
HIGHER TERRAIN ACRS CNY).
SUN NGT-MON NGT... A LARGE SFC HIGH WILL BUILD INTO NY/PA FROM THE
UPR MIDWEST. THIS WILL LEAD TO A CLEARING AND COOL NGT SUN
NGT...FOLLOWED BY PTLY-MSTLY SUNNY SKIES MON...WITH HIGHS MAINLY
IN THE 70S...AS THE COOLEST PTN OF THE AMS (850 MB TEMPS OF 4-6 C
AT 12Z MON) BEGINS TO SHIFT TO OUR NE INTO NRN NEW ENG. WAA MON
NGT COULD WELL LEAD TO SOME INCREASE IN MID TO UPR-LVL CLDNS...BUT
CONDS STILL LOOK RAIN-FREE.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
RISING HGTS ON TUE WILL RESULT IN SOME INCRSG CLDS BUT SHWRS SHD
BE LIMITED DUE TO STUBBORN LL DRY AIR. YET ANOTHER DIGGING LOW
APCHS FOR WED AND THU AND PUSHES A SFC BNDRY THRU THE AREA. GOOD
GULF CONNECTIONS SHD LEAD TO GOOD CVRG OF SHWRS AND TRWS LATE WED
INTO THU AHD OF THE TROF. DRIER AND COOLER AIR RETURNS ON FRI BHD
THE FNT. ATTM IT LOOKS DRY BHD THE FNT BUT EVENTUALLY THE LWRG
HGTS WITH THE LRG UA LOW WILL RESULT IN MAINLY AFTN CONV.
TEMPS WILL CONT TO AVG WELL BLO SEASONAL NORMS THRU THE PD. MEX
GUID WAS RUNNING A BIT HIER THRU THE PD THAN HPC BUT SEEMED LIKE
THE COOLER EURO HAD A BETTER HANDLE ON THE UA LOW SO MORE CLOSELY
FLWD HPC GUID.
&&
.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
MUCH DRIER AIR CONTS TO STREAM INTO THE AREA BRINGING VFR CIGS AND
VSBYS. SHRT WV DROPPING INTO THE UPR TROF WILL RETURN MVFR CIGS
LATE TNGT AS THE WV GRABS MOISTURE OFF THE LAKES. OCNL SHRA OVER
THE RME AND SYR PSBL AFT 08Z SHD NOT LIMT THE VSBYS. MVFR/VFR CIGS
WILL CONT THRU THE END OF THE TAF PD WITH A CAA NW FLOW REGIME.
WINDS WILL BE COME LGT TNGT...THEN NW ONCE AGAIN ON SUN WITH
MIXING.
MON THRU WED...MAINLY VFR.
THU...MVFR IN SHRA AND TSRA.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...DJN
NEAR TERM...DJN
SHORT TERM...MLJ
LONG TERM...DGM
AVIATION...DGM
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
152 PM EDT SAT AUG 3 2013
.SYNOPSIS...
A COLD FRONT WILL GRADUALLY CROSS THE REGION THIS AFTERNOON.
ALTHOUGH A FEW SHOWERS WILL PRECEDE THIS SYSTEM...MUCH OF THE DAY
IS EXPECTED TO BE RAIN FREE. A COOLER NORTHWEST AIR FLOW WILL
FOLLOW FOR THE SECOND HALF OF THE WEEKEND...ALONG WITH A FEW HIT
AND MISS SHOWERS ON SUNDAY...MAINLY OVER CENTRAL NEW YORK.
&&
.NEAR TERM /THROUGH SUNDAY/...
RADAR WAS LARGELY FREE OF ECHOES EARLY THIS AFTERNOON EXCEPT FOR A
FEW VERY ISLD SHRA OCCASIONALLY POPPING UP HERE AND THERE BUT
BEING SHORT-LIVED. ACVTY SEEMS TO BE A TAD MORE PREVALENT IN NE
PA NR SFC FRNT WHICH EXTENDED FROM NRN CATSKILLS TO BTWN IPT AND
AVP IN NE PA IN OUR FORECAST AREA. WATER VAPOR IMAGERY SHOWS
SIGNIFICANT UPPER LEVEL WAVE MOVG ACRS NRN NEW ENGLAND AND SERN
CANADA. THIS WAVE WAS ENHANCING STRG UPR CONFLUENCE ACRS NEW
ENGLAND TO NOVA SCOTIA AND HENCE AN UPPER LEVEL JET STREAK WAS
POSITIONED IN THIS AREA. ENHANCED DVRG IN THE RR QUAD OF THE JET
WAS PROMOTING SOME LIFTING INTO NE PA AND ITS LOWER LEVEL AGEO
FORCING WAS ALSO PUSH THE FRNT SOUTHWARD. BEST SHOT OF A FEW SHRA
AND EVEN A LITTLE TSRA WILL BE MAINLY ACRS OUR FAR SE FORECAST
AREA IN THE POCONOS TO SRN CATSKILLS FOR THE REST OF THE
AFTERNOON DUE TO THIS DYNAMICAL FORCING. NORTH OF THE FRNT...THE
CUMULUS WAS BUILDING BUT NOT TO EXTENT THAT I EARLIER THHOUGHT.
THE ONLY EXCEPTION WAS OVER AREAS DIRECTLY DOWNWIND OF LAKE
ONTARIO WHERE LAKE MOISTURE WAS ENHANCING LL MOISTURE AND LEADING
TO DEEPER CUMULUS AND A LITTLE ISLD SHRA ACVTY AT TIMES. HENCE
HAVE SOME ISLD CHC OF SHRA WELL N OF THE FRNT ACRS CNTRL NY AND
NRN PA. THIS ACVTY WILL WANE SOON EXCEPT IN NC NY DOWNWIND OF LAKE
ONTARIO.
FOR TONIGHT...INITIALLY CUMULUS AND ISLD SHRA WILL FALL APART WITH
LOSS OF INSOLATION. CONTINUED LL NW FLOW AND CAA WILL CONT ACRS
THE RELATIVELY WARM WATERS OF LAKE ONTARIO. LAKE ONTARIO TEMPS
WERE RUNNING ARND 20-21C AS 850 MB TEMPS DROP TO ARND 7-8C OR SO BY
LATE TONIGHT. ADDTNLY ANOTHER SHRT WAVE WILL DROP SOUTHWARD
OVERNIGHT REACHING SOUTHEAST ONTARIO AND WESTERN QUEBEC BY 12Z.
LIFTING FROM THIS WAVE IN ASSCTN WITH LAKE MOISTURE WILL TRIGGER
SHRA AGAIN LATER TONIGHT IN NC NY...WITH NO PRECIPITATION EXPECTED
IN SC NY DOWN TO NE PA BEFORE 12Z.
THEN FOR SUNDAY...UPPER LEVEL WAVE PASSES TO THE EAST BUT IS
FOLLOWING BY AN EVEN CHILLIER SHOT OF AIR WITH 850 MB TEMPS
DROPPING TO ARND 6C WHICH IS ABT A 14-15C DIFFERENTIAL. THE FLOW
REMAINS ABT 310 OR SO WHICH WILL BRING LAKE MOISTURE DOWN INTO THE
HILLS OF NC NY AND DOWN TO SC NY AND FAR NE PA. WITH INSOLATION
AND COLD TEMPERATURES AT 850 MB I SEE ISLD TO SCT SHRA FROM NRN PA
TO SC NY AND SCT SHRA INTO NC NY DIRECTLY DOWNWIND OF LAKE
ONTARIO. THE ACVTY WILL WANE LATER IN THE DAY AS INSOLATION BREAKS
UP ANY ORGANIZED LAKE EFFECT RAINS. HAVE SLGHT CHC IN NE PA TO LO
CHC IN SC NY TO HIGH CHC IN NC NY FOR SUNDAY.
&&
.SHORT TERM /SUNDAY NIGHT THROUGH MONDAY NIGHT/...
5 AM UPDATE... DEEPENING NW FLOW TNT-SUN...AS THE MAIN UPR LVL
TROUGH AXIS SHIFTS INTO QUE...WILL ALLOW A COOLER AMS TO SPREAD
INTO NY/PA. LINGERING LOW LVL MOISTURE WILL COMBINE WITH THE
PASSAGE OF ANOTHER S/WV LATE TNT INTO SUN...TO BRING SCTD -SHRA
ACRS OUR CNY ZNS...ALSO HELPED BY SOME UPSLOPING VIA NWLY FLOW.
925-850 MB CAA ON SUN...ALG WITH AT LEAST MRNG CLDNS/SCTD
-SHRA...WILL BRING COOLER READINGS (AS MENTIONED ABV)...WITH HIGH
TEMPS PERHAPS STAYING IN THE UPR 60S FOR SXNS OF THE FA (SPCLY THE
HIGHER TERRAIN ACRS CNY).
SUN NGT-MON NGT... A LARGE SFC HIGH WILL BUILD INTO NY/PA FROM THE
UPR MIDWEST. THIS WILL LEAD TO A CLEARING AND COOL NGT SUN
NGT...FOLLOWED BY PTLY-MSTLY SUNNY SKIES MON...WITH HIGHS MAINLY
IN THE 70S...AS THE COOLEST PTN OF THE AMS (850 MB TEMPS OF 4-6 C
AT 12Z MON) BEGINS TO SHIFT TO OUR NE INTO NRN NEW ENG. WAA MON
NGT COULD WELL LEAD TO SOME INCREASE IN MID TO UPR-LVL CLDNS...BUT
CONDS STILL LOOK RAIN-FREE.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
700 AM EDT UPDATE...
FORECAST IS IN GOOD SHAPE. NO CHANGES NEEDED.
PREVIOUS FORECAST...
LATEST EXTENDED MODEL GUIDANCE CONTINUING TO SUGGEST A FAIRLY COOL
PATTERN THROUGH THE TIME FRAME AS A WESTERN U.S. RIDGE DEVELOPS
AND A LARGE UPPER CLOSED LOW PREVAILS ACROSS THE CANADIAN PRAIRIE
PROVINCES. THIS COMBINED WITH STRONG UPPER RIDGING SOUTH OF
GREENLAND WILL ENSURE A FAIRLY STAGNANT UPPER PATTERN THROUGH THE
PERIOD. THAT SAID...SFC HIGH PRESSURE WILL BE IN FIRM CONTROL
EARLY IN THE TIME FRAME WHICH SHOULD LEAD TO FAIRLY COOL OVERNIGHT
LOWS TUE MORNING WITH LATEST GUIDANCE SUGGESTING MID TO UPPER 40S
A POSSIBILITY FOR THE TRANSITIONALLY COOLER VALLEY LOCATIONS. NEXT
WX FEATURE OF INTEREST SET TO ARRIVE LATE TUE/EARLY WED AS
SHORTWAVE ENERGY ROTATING ALONG THE EASTERN PERIPHERY OF CENTRAL
CANADIAN UPPER LOW SENDS A COLD FRONT ACROSS THE AREA. FOR
NOW...HAVE CAPPED POPS IN THE CHC CATEGORY WHICH AGREES WELL WITH
SURROUNDING OFFICES AND LATEST HPC GUIDANCE. FOLLOWING
THIS...ANOTHER QUICK COOL DOWN IS EXPECTED BY WEEK/S END AS NEXT
SURFACE HIGH PRESSURE SYSTEM SETTLES OVER THE CENTRAL/EASTERN
GREAT LAKES.
&&
.AVIATION /17Z SATURDAY THROUGH WEDNESDAY/...
700 AM EDT UPDATE...
MVFR CIGS HAVE DEVELOPED ACROSS MUCH OF THE REGION THIS MORNING.
AS THE MORNING PROGRESSES...MVFR CIGS WILL LIFT TO VFR. DRY AIR
IS FUNNELING INTO THE REGION FROM THE NORTHWEST AND WILL CONTINUE
TO THROUGH THE AFTERNOON... THUS CLOUDS WILL SLOWLY DIMINISH BY
LATE EVENING AND THE CHANCE FOR RAIN WILL BE MINIMAL. AN ISOLATED
SHOWER MAY DEVELOP BUT CHANCES ARE LOW THEREFORE DECIDED TO KEEP
OUT OF TAFS. SATURDAY NIGHT AS WINDS REMAIN FROM THE WEST AND MOVE
ACROSS THE LAKES... IFR CIGS SHOULD DEVELOP ACROSS THE AREA.
SUN THRU WED...MAINLY VFR...HOWEVER ISOLATED MVFR IN DAILY SHWRS
DURING THE AFTERNOON HRS.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...DJN
NEAR TERM...DJN
SHORT TERM...MLJ
LONG TERM...DGM
AVIATION...KAH
AREA FORECAST DISCUSSION
NWS RALEIGH NC
155 PM EDT SAT AUG 3 2013
.SYNOPSIS...
SEVERAL SHORTWAVE TROUGHS ACROSS CENTRAL NORTH CAROLINA WILL YIELD
UNSETTLED WEATHER THROUGH THE EVENING BEFORE A STRONGER COLD FRONT
APPROACHES FROM THE NORTH ON SUNDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 955 AM SATURDAY...
UPDATE: EARLIER SHOWERS IN THE SOUTHEAST HAVE ENDED AND LIGHT SHOWER
ACTIVITY HAS FORMED ON A SECONDARY BOUNDARY ACROSS THE NORTHWEST
PIEDMONT. BASED ON SURFACE ANALYSIS IT DOES APPEAR THAT THE ORIGINAL
BOUNDARY HAS WASHED OUT A BIT BUT IS POISED TO MAKE A COMEBACK LATER
THIS AFTERNOON AS A SMALL SHEAR AXIS EXISTS BETWEEN THE SANDHILLS
AND COASTAL PLAIN AND THIS COULD BE A FOCUS FOR SHOWER AND
THUNDERSTORM ACTIVITY THIS AFTERNOON. THEREFORE HAVE REMOVED POPS IN
THE SOUTHEAST THIS MORNING AND REPLACED THEM WITH SLIGHT CHANCE IN
THE NORTHERN TIER. HAVE LEFT POPS IN THE SOUTHEAST FOR THIS
AFTERNOON. AS FAR AS TEMPERATURES ARE CONCERNED STILL GOING WITH A
HIGH NEAR 90 BUT SUB-VFR CEILINGS HAVE HELD ON LONGER THAN
ANTICIPATED WHICH MAY AFFECT TEMPERATURES BUT AFTER THE CEILINGS
BREAK THERE SHOULD STILL BE ENOUGH INSOLATION TO HELP TEMPERATURES
QUICKLY RECOVER. PREVIOUS DISCUSSION FOLLOWS. - ELLIS
LINGERING...WEAK SURFACE BOUNDARY REMAINS OVER CENTRAL NORTH
CAROLINA...AND IN VICINITY OF THE BOUNDARY AND THE INSTABILITY
GRADIENT NOTED ON THE SPC MESOANALYSIS...ISOLATED SHOWERS CONTINUED
EARLY THIS MORNING. THE 00Z UPPER-AIR ANALYSIS ALSO SHOWED A PARADE
OF 700MB SHORTWAVES MOVING TOWARD THE AREA IN THE NORTHWEST FLOW
ALOFT...AND THE LATEST HRRR WRF NOTES A FEW SHOWERS LINGERING
THROUGH DAWN IN CENTRAL NORTH CAROLINA. FOLLOWING THIS...THE 850MB
THETA-E RIDGE PERSISTS OVER CENTRAL NORTH CAROLINA THROUGHOUT THE
DAY IN VICINITY OF THE REMNANT BOUNDARY. ALTHOUGH JET SUPPORT IS
WELL NORTH AND NORTHWEST AND OVERALL LIFT IS FORECAST TO BE MODEST
AT BEST ON THE GFS...INSTABILITY OF AROUND 1500J/KG DURING THE
AFTERNOON SHOULD BE ENOUGH TO RESULT IN SCATTERED SHOWERS AND
THUNDERSTORMS PER A BLEND OF THE MAV AND MET MOS GUIDANCE...AND THE
CONSENSUS OF THE HIGH-RESOLUTION MODEL OUTPUT. THE CONSENSUS OF THAT
OUTPUT CERTAINLY PLACES THE HIGHER POTENTIAL FOR SCATTERED SHOWERS
AND THUNDERSTORMS IN VICINITY OF INTERSTATE 95...AND WILL SHOW THE
HIGHER CHANCES THERE FOR TODAY RELATIVE TO THE REST OF CENTRAL NORTH
CAROLINA...AGAIN CLOSER TO THE REMNANT BOUNDARY AND IN DEEPER
MOISTURE. IF THERE WAS FORECAST STRONGER LOW-LEVEL CONVERGENCE...
SHEAR...OR DIFFLUENCE ALOFT THERE MAY BE MORE CONFIDENCE IN NOTING
THE POTENTIAL FOR A LOCALLY SEVERE STORM IN THE HWO...BUT THESE
PARAMETERS ARE FORECAST TO BE SOMEWHAT WEAK ON THE GFS...THOUGH THE
0-3KM SHEAR APPROACHING 25KT IS BETTER THAN WHAT HAS BEEN NOTED IN
RECENT DAYS. WILL LIKELY NOTE THE POTENTIAL FOR A STRONG STORM IN
THE OUTLOOK...KEEPING IN MIND AN ISOLATED SEVERE STORM OR TWO CANNOT
BE COMPLETELY RULED OUT.
OVERNIGHT...A MAXIMUM OF INSTABILITY FORECAST BY THE GFS WEST OF THE
YADKIN RIVER...IN ADVANCE OF AN INCREASE IN POTENTIAL VORTICITY ON
THE 1.5 PVU SURFACE LATE THIS AFTERNOON AND THIS EVENING...MAY HELP
PROVIDE FOR SCATTERED SHOWERS AND THUNDERSTORMS MOVING INTO CENTRAL
NORTH CAROLINA FROM THE WEST...AND LINGERING INTO THE OVERNIGHT
HOURS EAST OF U.S. 1 AND INTO THE INTERSTATE 95 CORRIDOR. HIGHS
TODAY AROUND 90 MOST LOCATIONS WITH PARTLY SUNNY CONDITIONS ON
AVERAGE. OVERNIGHT LOWS TONIGHT UPPER 60S TO MID 70S NORTH TO
SOUTH.-DJF
&&
.SHORT TERM /SUNDAY AND SUNDAY NIGHT/...
AS OF 305 AM SATURDAY...
A COLD FRONT APPROACHES FROM THE NORTH AND MOVES THROUGH CENTRAL
NORTH CAROLINA DURING THE DAY SUNDAY. IN ADVANCE OF WHAT APPEARS TO
BE THE TRUE FRONT...WINDS SHOULD VEER NORTHWEST THEN BECOME MORE
TRUE NORTH OR NORTH-NORTHEAST BEHIND THE FRONT. THE 850MB FRONT
LINGERS AND IS NOT FORECAST BY THE GFS TO MOVE THROUGH CENTRAL NORTH
CAROLINA UNTIL THE EARLY AFTERNOON. THETA-E RIDGING AT 850MB SHIFTS
SOUTH ALONG WITH HIGHER VALUES OF K INDICES...AND BY AFTERNOON THE
BEST UPPER-LEVEL DIVERGENCE IS FORECAST SOUTH OF THE STATE ACROSS
SOUTH CAROLINA...WHERE THE GFS IS FAIRLY AMPLE WITH THAT PARAMETER
DURING THE AFTERNOON. BUFR SOUNDINGS SHOW INCREASING STABILITY...
ALTHOUGH THE GFS BUFR SOUNDINGS AT KFAY AND KRWI ARE CLOSER TO THE
MOIST ADIABAT IN THE TEMPERATURE PROFILE INTO SUNDAY AFTERNOON.
BESIDES THE POTENTIAL FOR AN ISOLATED SHOWER SUNDAY MORNING...IT MAY
BE DIFFICULT TO GET ANY PRECIPITATION ALONG AND NORTH OF U.S. 64
SUNDAY. CLOSER TO THE SOUTH CAROLINA BORDER...UNTIL THE 850MB FRONT
GOES THROUGH WITH ITS ASSOCIATED LIFT...AND WHILE DEW POINTS ARE
STILL AT LEAST IN THE MID 60S...AN ISOLATED-TO-SCATTERED SHOWER OR
STORM REMAINS POSSIBLE. MLCAPE IN THE LOWEST KM IS HIGHER THERE THAN
ELSEWHERE...AND DCAPE IS AT LEAST 1000J/KG IN THE FAR SOUTH
SUNDAY...WITH INCREASING SHEAR MAKING A STRONG STORM POSSIBLE THERE
IF ONE CAN DEVELOP. BY SUNSET...THIS POTENTIAL SHOULD BE LOCATED
SOUTH OF CENTRAL NORTH CAROLINA ALTOGETHER. AFTER HIGHS SUNDAY FROM
THE UPPER 80S TO LOWER 90S...OVERNIGHT LOWS IN THE DRIER AIR SHOULD
BE IN THE 60S...APPROACHING 60 ESPECIALLY NORTH OF U.S. 64.
&&
.LONG TERM /MONDAY THROUGH SATURDAY/...
AS OF 155 PM SATURDAY...
MONDAY...
A COLD FRONT PASSING TO THE SOUTH OF THE AREA WILL GIVE WAY TO A
PLEASANT DAY ON MONDAY WITH HIGH PRESSURE EDGING INTO NC FROM THE
NORTH. A SHOT OF LOWER DEWPOINTS IN THE UPPER 50S AND LOWER 60S
WILL LIMIT INSTABILITY AND THE FORECAST WILL BE DRY. THE UPPER
LEVEL FLOW WILL REMAIN NORTHWESTERLY CYCLONIC FLOW PERSISTS OVER
EASTERN CANADA. MODELS INDICATE SOME CIRRUS MAY SPILL INTO WESTERN
NC LATE IN THE DAY AHEAD OF CONVECTION OVER THE MIDWEST. HIGHS WILL
BE BELOW NORMAL IN THE MID AND UPPER 80S.
MONDAY NIGHT THROUGH TUESDAY NIGHT...
THE PROGRESSIVE HIGH PRESSURE JUST TO OUR NORTH WILL MOVE QUICKLY
OFFSHORE...MAINTAINING SOME INFLUENCE OVER THE NORTHEASTERN CWA
WHILE ALLOWING RETURN FLOW TO DEVELOP OVER THE WEST BY MONDAY
NIGHT. THIS INCREASING MOISTURE COMBINED WITH THE POTENTIAL FOR A
DISTURBANCE UPSTREAM TO ADVECT SOUTHEAST ACROSS THE APPALACHIANS MAY
LEAD TO SHOWERS/STORMS OVER THE WESTERN PORTION OF THE CWA LATE
MONDAY NIGHT...CONTINUING INTO TUESDAY. CONFIDENCE IN COVERAGE IS
LOW AT THIS TIME DUE TO UNCERTAINTY IN NORTHWEST FLOW PATTERNS...BUT
THERE IS ENOUGH MODEL AGREEMENT FOR AT LEAST A SLIGHT CHANCE OVER
THE NORTHWEST PIEDMONT MONDAY NIGHT...WITH A SOLID CHANCE ON
TUESDAY. LOWS ON MONDAY NIGHT SHOULD RANGE FROM THE MID/UPPER 60S
IN THE SOUTH AND WEST TO LOWER 60S IN THE NORTHEAST. HIGHS TUESDAY
IN THE LOW TO MID 80S.
WEDNESDAY THROUGH SATURDAY...
MOIST SOUTHERLY FLOW WILL DOMINATE IN THE LOW LEVELS FOR THE LATER
HALF OF THE WEEK..WHILE THE UPPER LEVEL FLOW FLATTENS OUT A BIT IN
RESPONSE TO THE UPPER LEVEL RIDGE BUILDING FROM THE SOUTHERN PLAIN
ACROSS THE DEEP SOUTH. PRECIP CHANCES SHOULD BE MOSTLY
CLIMATOLOGICAL WEDNESDAY AND THURSDAY WITH DIURNAL SHOWERS AND
STORMS FAVORED SLIGHTLY OVER THE WEST. BY THE END OF THE
WEEK...A SLOW MOVING COLD FRONT...ATTENDANT TO AN UPPER-LEVEL LOW
OVER THE NORTHERN GREAT LAKES...WILL SLIP SOUTHEAST INTO OUT
REGION. BASED ON CURRENT MODEL PROJECTIONS...THE DYNAMIC FORCING
AND MOISTURE WILL BE LIMITED...AND THE FRONT MAY HAVE A HARD TIME
MAKING IT ALL THE WAY THROUGH NC. NONETHELESS...THERE SHOULD BE A
PERIOD OF HIGHER THAN NORMAL POPS BETWEEN LATE FRIDAY AND SATURDAY.
HIGHS MOSTLY IN THE MID AND UPPER 80S.
&&
.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
AS OF 130 PM SATURDAY...
24 HOUR TAF PERIOD: A FEW MVFR CEILINGS HANGING ON OUT THERE BUT
CONDITIONS HAVE GONE LARGELY VFR. EASTERN TERMINALS INCLUDING KRDU
WILL BE AT GREATER RISK FOR SHOWERS AND THUNDERSTORMS THIS AFTERNOON
COMPARED TO KINT AND KGSO. LOCALIZED HEAVY RAIN AND ISOLATED SEVERE
STORMS ARE POSSIBLE WITH WIND THE PRIMARY THREAT. A MORE PROMINENT
BOUNDARY SETTING UP FROM SOUTHWEST TO NORTHEAST NEAR THE I-95
CORRIDOR WILL MAKE KFAY AND KRWI THE MOST LIKELY PLACE FOR STORMS
THIS AFTERNOON..ESPECIALLY AS THE SEA BREEZE BEGINS TO INTERACT WITH
THIS BOUNDARY. OTHERWISE EXPECT SOUTHWESTERLY WINDS AT 5-10 KNOTS
THROUGH THE AFTERNOON INTO THE EVENING. OVERNIGHT THERE WILL ONCE
AGAIN BE A CHANCE FOR FOG AND LOW STRATUS AT MOST LOCATIONS WITH
MVFR VISIBILITIES AND/OR IFR CEILINGS THE MOST LIKELY IMPACTS. FOR
SUNDAY A FRONT WILL CROSS THE AREA FROM NORTH TO SOUTH AND WINDS
WILL BECOME NORTHERLY NEAR 10 KNOTS AFTER FRONTAL PASSAGE WITH SOME
GUSTS TO 15 KNOTS EXPECTED IN THE AFTERNOON. SCATTERED TO BROKEN
CEILINGS NEAR 7 KFT SHOULD PREVAIL THROUGH THE END OF THE TAF PERIOD.
LONG TERM: MONDAY SHOULD SEE VFR CONDITIONS PREVAIL WITH INCREASING
CHANCES FOR CONVECTION AND SUB-VFR CONDITIONS THROUGH MIDWEEK BEFORE
A WEAK FRONT APPROACHES FOR THE END OF THE WEEK.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...ELLIS
NEAR TERM...ELLIS/DJF
SHORT TERM...DJF
LONG TERM...SMITH
AVIATION...ELLIS
AREA FORECAST DISCUSSION
NWS RALEIGH NC
135 PM EDT SAT AUG 3 2013
.SYNOPSIS...
SEVERAL SHORTWAVE TROUGHS ACROSS CENTRAL NORTH CAROLINA WILL YIELD
UNSETTLED WEATHER THROUGH THE EVENING BEFORE A STRONGER COLD FRONT
APPROACHES FROM THE NORTH ON SUNDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 955 AM SATURDAY...
UPDATE: EARLIER SHOWERS IN THE SOUTHEAST HAVE ENDED AND LIGHT SHOWER
ACTIVITY HAS FORMED ON A SECONDARY BOUNDARY ACROSS THE NORTHWEST
PIEDMONT. BASED ON SURFACE ANALYSIS IT DOES APPEAR THAT THE ORIGINAL
BOUNDARY HAS WASHED OUT A BIT BUT IS POISED TO MAKE A COMEBACK LATER
THIS AFTERNOON AS A SMALL SHEAR AXIS EXISTS BETWEEN THE SANDHILLS
AND COASTAL PLAIN AND THIS COULD BE A FOCUS FOR SHOWER AND
THUNDERSTORM ACTIVITY THIS AFTERNOON. THEREFORE HAVE REMOVED POPS IN
THE SOUTHEAST THIS MORNING AND REPLACED THEM WITH SLIGHT CHANCE IN
THE NORTHERN TIER. HAVE LEFT POPS IN THE SOUTHEAST FOR THIS
AFTERNOON. AS FAR AS TEMPERATURES ARE CONCERNED STILL GOING WITH A
HIGH NEAR 90 BUT SUB-VFR CEILINGS HAVE HELD ON LONGER THAN
ANTICIPATED WHICH MAY AFFECT TEMPERATURES BUT AFTER THE CEILINGS
BREAK THERE SHOULD STILL BE ENOUGH INSOLATION TO HELP TEMPERATURES
QUICKLY RECOVER. PREVIOUS DISCUSSION FOLLOWS. - ELLIS
LINGERING...WEAK SURFACE BOUNDARY REMAINS OVER CENTRAL NORTH
CAROLINA...AND IN VICINITY OF THE BOUNDARY AND THE INSTABILITY
GRADIENT NOTED ON THE SPC MESOANALYSIS...ISOLATED SHOWERS CONTINUED
EARLY THIS MORNING. THE 00Z UPPER-AIR ANALYSIS ALSO SHOWED A PARADE
OF 700MB SHORTWAVES MOVING TOWARD THE AREA IN THE NORTHWEST FLOW
ALOFT...AND THE LATEST HRRR WRF NOTES A FEW SHOWERS LINGERING
THROUGH DAWN IN CENTRAL NORTH CAROLINA. FOLLOWING THIS...THE 850MB
THETA-E RIDGE PERSISTS OVER CENTRAL NORTH CAROLINA THROUGHOUT THE
DAY IN VICINITY OF THE REMNANT BOUNDARY. ALTHOUGH JET SUPPORT IS
WELL NORTH AND NORTHWEST AND OVERALL LIFT IS FORECAST TO BE MODEST
AT BEST ON THE GFS...INSTABILITY OF AROUND 1500J/KG DURING THE
AFTERNOON SHOULD BE ENOUGH TO RESULT IN SCATTERED SHOWERS AND
THUNDERSTORMS PER A BLEND OF THE MAV AND MET MOS GUIDANCE...AND THE
CONSENSUS OF THE HIGH-RESOLUTION MODEL OUTPUT. THE CONSENSUS OF THAT
OUTPUT CERTAINLY PLACES THE HIGHER POTENTIAL FOR SCATTERED SHOWERS
AND THUNDERSTORMS IN VICINITY OF INTERSTATE 95...AND WILL SHOW THE
HIGHER CHANCES THERE FOR TODAY RELATIVE TO THE REST OF CENTRAL NORTH
CAROLINA...AGAIN CLOSER TO THE REMNANT BOUNDARY AND IN DEEPER
MOISTURE. IF THERE WAS FORECAST STRONGER LOW-LEVEL CONVERGENCE...
SHEAR...OR DIFFLUENCE ALOFT THERE MAY BE MORE CONFIDENCE IN NOTING
THE POTENTIAL FOR A LOCALLY SEVERE STORM IN THE HWO...BUT THESE
PARAMETERS ARE FORECAST TO BE SOMEWHAT WEAK ON THE GFS...THOUGH THE
0-3KM SHEAR APPROACHING 25KT IS BETTER THAN WHAT HAS BEEN NOTED IN
RECENT DAYS. WILL LIKELY NOTE THE POTENTIAL FOR A STRONG STORM IN
THE OUTLOOK...KEEPING IN MIND AN ISOLATED SEVERE STORM OR TWO CANNOT
BE COMPLETELY RULED OUT.
OVERNIGHT...A MAXIMUM OF INSTABILITY FORECAST BY THE GFS WEST OF THE
YADKIN RIVER...IN ADVANCE OF AN INCREASE IN POTENTIAL VORTICITY ON
THE 1.5 PVU SURFACE LATE THIS AFTERNOON AND THIS EVENING...MAY HELP
PROVIDE FOR SCATTERED SHOWERS AND THUNDERSTORMS MOVING INTO CENTRAL
NORTH CAROLINA FROM THE WEST...AND LINGERING INTO THE OVERNIGHT
HOURS EAST OF U.S. 1 AND INTO THE INTERSTATE 95 CORRIDOR. HIGHS
TODAY AROUND 90 MOST LOCATIONS WITH PARTLY SUNNY CONDITIONS ON
AVERAGE. OVERNIGHT LOWS TONIGHT UPPER 60S TO MID 70S NORTH TO
SOUTH.-DJF
&&
.SHORT TERM /SUNDAY AND SUNDAY NIGHT/...
AS OF 305 AM SATURDAY...
A COLD FRONT APPROACHES FROM THE NORTH AND MOVES THROUGH CENTRAL
NORTH CAROLINA DURING THE DAY SUNDAY. IN ADVANCE OF WHAT APPEARS TO
BE THE TRUE FRONT...WINDS SHOULD VEER NORTHWEST THEN BECOME MORE
TRUE NORTH OR NORTH-NORTHEAST BEHIND THE FRONT. THE 850MB FRONT
LINGERS AND IS NOT FORECAST BY THE GFS TO MOVE THROUGH CENTRAL NORTH
CAROLINA UNTIL THE EARLY AFTERNOON. THETA-E RIDGING AT 850MB SHIFTS
SOUTH ALONG WITH HIGHER VALUES OF K INDICES...AND BY AFTERNOON THE
BEST UPPER-LEVEL DIVERGENCE IS FORECAST SOUTH OF THE STATE ACROSS
SOUTH CAROLINA...WHERE THE GFS IS FAIRLY AMPLE WITH THAT PARAMETER
DURING THE AFTERNOON. BUFR SOUNDINGS SHOW INCREASING STABILITY...
ALTHOUGH THE GFS BUFR SOUNDINGS AT KFAY AND KRWI ARE CLOSER TO THE
MOIST ADIABAT IN THE TEMPERATURE PROFILE INTO SUNDAY AFTERNOON.
BESIDES THE POTENTIAL FOR AN ISOLATED SHOWER SUNDAY MORNING...IT MAY
BE DIFFICULT TO GET ANY PRECIPITATION ALONG AND NORTH OF U.S. 64
SUNDAY. CLOSER TO THE SOUTH CAROLINA BORDER...UNTIL THE 850MB FRONT
GOES THROUGH WITH ITS ASSOCIATED LIFT...AND WHILE DEW POINTS ARE
STILL AT LEAST IN THE MID 60S...AN ISOLATED-TO-SCATTERED SHOWER OR
STORM REMAINS POSSIBLE. MLCAPE IN THE LOWEST KM IS HIGHER THERE THAN
ELSEWHERE...AND DCAPE IS AT LEAST 1000J/KG IN THE FAR SOUTH
SUNDAY...WITH INCREASING SHEAR MAKING A STRONG STORM POSSIBLE THERE
IF ONE CAN DEVELOP. BY SUNSET...THIS POTENTIAL SHOULD BE LOCATED
SOUTH OF CENTRAL NORTH CAROLINA ALTOGETHER. AFTER HIGHS SUNDAY FROM
THE UPPER 80S TO LOWER 90S...OVERNIGHT LOWS IN THE DRIER AIR SHOULD
BE IN THE 60S...APPROACHING 60 ESPECIALLY NORTH OF U.S. 64.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
AS OF 255 AM SATURDAY...
HIGH PRESSURE WILL MOVE ACROSS THE MID ATLANTIC REGION ON MONDAY...
MOVING OFFSHORE BY 00Z TUE AS A MID LEVEL SHORT WAVE EMBEDDED IN THE
NW FLOW MOVES SE ACROSS THE MIDWEST. A DRY AIRMASS OVER THE STATE
EARLY MONDAY...PER FORECAST SOUNDINGS WHICH SHOW PWAT JUST BELOW ONE
INCH...WILL QUICKLY MODIFY AS THE DAY PROGRESSES AND THE HIGH MOVES
OFFSHORE. PWAT ON THESE SAME FORECAST SOUNDINGS ARE SHOWN TO
INCREASE TO AROUND 1.5 INCHES BY 03Z TUE. EVEN WITH INCREASING
MOISTURE...WILL KEEP THE FORECAST DRY ON MONDAY DUE TO VERY LIMITED
SYNOP SCALE AND LOW LEVEL FORCING.
THE AFOREMENTIONED SHORT WAVE IS PROGGED TO CROSS THE MOUNTAINS
MONDAY NIGHT AND MOVE ACROSS MID ATLANTIC AND CAROLINAS ON TUESDAY.
THE COMBINATION OF INCREASING MOISTURE AND SYNOPTIC SCALE FORCING
WITH THE SHORT WAVE WILL BRING INCREASED RAIN CHANCES TO THE AREA
LATE MONDAY NIGHT ACROSS OUR WESTERN ZONES...AND TUESDAY ACROSS ALL
OF CENTRAL NC.
DURING THE MID-WEEK PERIOD...THE WESTERLIES WILL SHIFT NORTH WITH A
WEAK RIDGE BECOMING ESTABLISHED ACROSS OUR AREA. THIS PATTERN WILL
RESULT IN A MORE TYPICAL SUMMERTIME PATTERN WITH ISOLATED TO
SCATTERED AFTERNOON/EVENING SHOWERS AND TSTMS.
BY LATE WEEK...THE NEXT SHORT WAVE AND COLD FRONT WILL APPROACH FROM
THE NW...THUS LOOK FOR INCREASING RAIN CHANCES ESP LATE ON FRIDAY.
THIS SOLUTION IS SLIGHTLY LATER IN TIMING THAN EARLIER MODEL
RUNS...WHICH BROUGHT THIS SAME SYSTEM IN AS EARLY AS LATE THURSDAY.
TEMPS DURING THE LONG TERM: A FEW DEGREES BELOW NORMAL TO START OFF
THE WEEK (LOWS IN THE MID 60S AND HIGHS IN THE MID-UPPER 80S) AS LOW
LEVEL THICKNESSES DECREASE IN THE WAKE OF THE TROUGH PASSAGE. THEN
TEMPERATURES WILL REBOUND TO NORMAL (LOWS IN THE UPPER 60S TO NEAR
70 AND HIGHS IN THE UPPER 80S TO NEAR 90) DURING THE MID-LATE WEEK
PERIOD AS THE RIDGE BUILDS OVER THE REGION.
&&
.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
AS OF 130 PM SATURDAY...
24 HOUR TAF PERIOD: A FEW MVFR CEILINGS HANGING ON OUT THERE BUT
CONDITIONS HAVE GONE LAREGELY VFR. EASTERN TERMINALS INCLUDING KRDU
WILL BE AT GREATER RISK FOR SHOWERS AND THUNDERSTORMS THIS AFTERNOON
COMPARED TO KINT AND KGSO. LOCALIZED HEAVY RAIN AND ISOLATED SEVERE
STORMS ARE POSSIBLE WITH WIND THE PRIMARY THREAT. A MORE PROMINANT
BOUNDARY SETTING UP FROM SOUTHWEST TO NORTHEAST NEAR THE I-95
CORRIDOR WILL MAKE KFAY AND KRWI THE MOST LIKELY PLACE FOR STORMS
THIS AFTERNOON..ESPECIALLY AS THE SEA BREEZE BEGINS TO INTERACT WITH
THIS BOUNDARY. OTHERWISE EXPECT SOUTHWESTERLY WINDS AT 5-10 KNOTS
THROUGH THE AFTERNOON INTO THE EVENING. OVERNIGHT THERE WILL ONCE
AGAIN BE A CHANCE FOR FOG AND LOW STRATUS AT MOST LOCATIONS WITH
MVFR VISIBILITES AND/OR IFR CEILINGS THE MOST LIKELY IMPACTS. FOR
SUNDAY A FRONT WILL CROSS THE AREA FROM NORTH TO SOUTH AND WINDS
WILL BECOME NORTHERLY NEAR 10 KNOTS AFTER FRONTAL PASSAGE WITH SOME
GUSTS TO 15 KNOTS EXPECTED IN THE AFTERNOON. SCATTERED TO BROKEN
CEILINGS NEAR 7 KFT SHOULD PREVAIL THROUGH THE END OF THE TAF PERIOD.
LONG TERM: MONDAY SHOULD SEE VFR CONDITIONS PREVAIL WITH INCREASING
CHANCES FOR CONVECTION AND SUB-VFR CONDITIONS THROUGH MIDWEEK BEFORE
A WEAK FRONT APPROACHES FOR THE END OF THE WEEK.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...ELLIS
NEAR TERM...ELLIS/DJF
SHORT TERM...DJF
LONG TERM...NP
AVIATION...ELLIS
AREA FORECAST DISCUSSION
NWS BISMARCK ND
321 PM CDT SAT AUG 3 2013
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 321 PM CDT SAT AUG 3 2013
MAIN FORECAST PROBLEM IN THE SHORT TERM PERIOD WILL BE
THUNDERSTORM CHANCES.
CURRENTLY...ALTHOUGH NOT REAL WARM...A MOIST UNSTABLE ATMOSPHERE
IS DEVELOPING ACROSS EASTERN MONTANA AND FAR WESTERN NORTH DAKOTA.
A SHORTWAVE INDICATED OVER NORTH CENTRAL MONTANA IN A PROGRESSIVE
BAND OF WESTERLIES HAS INITIATED CONVECTION WEST OF GLASGOW.
EXPECT CONVECTION TO CONTINUE TO INCREASE IN AN AREA OF STEEPENING
LAPSE RATES AND STRONG DEEP LAYER SHEAR. THE 18 UTC HRRR INDICATES
DISCRETE SUPERCELLS TRACKING ACROSS EASTERN MONTANA THIS AFTERNOON
AND EVENING...CLIPPING THE FAR SOUTHWEST LATE THIS EVENING. THE
12 UTC WRF AND HIRES-NMM/ARW ARE SIMILAR BUT MAYBE A BIT LATER AND
TRANSITION FROM DISCRETE CELLS INTO AN MCS THAT TRACKS ACROSS THE
SOUTHWEST AND FAR SOUTH CENTRAL LATE TONIGHT INTO SUNDAY MORNING.
WHATEVER EVENTUALLY PANS OUT...WILL DEFINITELY BUMP UP POPS
TONIGHT AND SUNDAY. HAVE INCLUDED A MENTION OF SEVERE ACROSS THE
SOUTHWEST THIS EVENING. AFTER MIDNIGHT...ALTHOUGH A SEVERE STORM
CANNOT BE RULED OUT...THINK WE WILL BE ON THE DOWNWARD TREND.
HIGH TEMPERATURES ON SUNDAY WILL DEPEND GREATLY ON THE ONGOING
CONVECTION THAT TRACKS ACROSS CENTRAL INTO EASTERN NORTH DAKOTA
DURING THE DAY. UTILIZED A BLEND WITH MORE WEIGHT TOWARD RAW MODEL
GUIDANCE WHICH USUALLY WORKS WELL IN A CHANGEABLE WEATHER PATTERN.
THIS RESULTS IN A NICE GRADIENT FROM UPPER 60S ACROSS THE NORTH
CENTRAL WHERE SHOWERS HANG ON INTO THE AFTERNOON...TO AROUND 80
OVER THE SOUTHWEST WHERE WE CLEAR OUT EARLY AND TEMPERATURES
REBOUND NICELY. THE WEST WILL ALSO BEGIN TO DESTABILIZE ONCE
AGAIN SUNDAY AFTERNOON...WITH A FAVORABLE SHEAR ENVIRONMENT
REMAINING OVER THE AREA. WILL NOT MENTION SEVERE WORDING AT THIS
TIME BUT WILL KEEP A CHANCE OF THUNDERSTORMS REMAINING ACROSS ALL
OF WESTERN NORTH DAKOTA SUNDAY AFTERNOON.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 321 PM CDT SAT AUG 3 2013
CHANCES FOR PRECIPITATION WILL DECREASE WEST TO EAST SUNDAY
EVENING INTO EARLY MONDAY MORNING AS A MID LEVEL SHORTWAVE TROUGH
AND AREA OF SURFACE LOW PRESSURE MOVE EAST INTO THE GREAT LAKES
REGION AND SURFACE HIGH PRESSURE BUILDS ACROSS WESTERN NORTH
DAKOTA.
WE REMAIN IN NORTHWEST FLOW ALOFT MONDAY WITH UPPER LEVEL RIDGING
ACROSS THE SOUTHERN PLAINS AND DEEP LOW PRESSURE OVER THE WESTERN
HUDSON BAY. WILL SEE INCREASING CHANCES OF SHOWERS/THUNDERSTORMS
LATER MONDAY WEST AND NORTH AND MONDAY NIGHT AREA WIDE AS THE
UPPER LOW DRIFTS SOUTHWARD ALLOWING FOR INCREASING CYCLONIC FLOW
ALOFT INTO THE NORTHERN PLAINS. MODELS ARE KEYING IN ON TWO
DISTINCT MID LEVEL IMPULSES ROTATING THROUGH THE FLOW ACROSS NORTH
DAKOTA...IN ADDITION TO A SFC TROUGH/COLD FRONTAL BOUNDARY PUSHING
SOUTH ACROSS THE STATE INTO TUESDAY MORNING. BEST CHANCES FOR
PRECIPITATION WILL BE ACROSS MY NORTH AND EAST WHERE BEST LOW
LEVEL FORCING IS CURRENTLY FORECAST.
BY TUESDAY AFTERNOON...THE UPPER LEVEL LOW IS FORECAST TO BE ABOUT
250-400 MILES NORTHEAST OF LAKE WINNIPEG MAINTAINING STRONG
CYCLONIC FLOW ALOFT...WHICH PERSISTS THROUGH WEDNESDAY. LINGERING
LOW LEVEL MOISTURE COUPLED WITH EMBEDDED ENERGY IN THE FLOW ALOFT
WILL MAINTAIN SOME CHANCE FOR DIURNALLY DRIVEN SHOWERS/ISOLATED
THUNDERSTORMS BOTH TUESDAY AND WEDNESDAY. HOWEVER...LOW LEVEL
FORCING IS PROGGED WEAK SO WIDESPREAD PRECIPITATION IS NOT
EXPECTED. IN ADDITION...MUCH COOLER CANADIAN AIR WILL FILTER INTO
THE REGION TUESDAY/TUESDAY NIGHT AND WEDNESDAY (HIGHS IN THE
LOW/MID 70S AND LOWS TUESDAY NIGHT LOW 50S/UPPER 40S).
UPPER LOW PROPAGATES SLOWLY EAST TO OVER ONTARIO THURSDAY...THEN
INTO EASTERN CANADA BY SATURDAY. HIGH PRESSURE IS FORECAST TO
BUILD ACROSS THE DAKOTAS THURSDAY AND THURSDAY NIGHT...REMAINING
IN PLACE WELL INTO SATURDAY. THIS WILL LEAD TO MAINLY DRY
CONDITIONS AND CONTINUED BELOW NORMAL TEMPERATURES OVER MOST OF
THE CWA THROUGH THE REMAINDER OF THE PERIOD.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 321 PM CDT SAT AUG 3 2013
MAIN CHALLENGE FOR THE AVIATION PERIOD WILL BE SHOWER AND
THUNDERSTORM ACTIVITY. THERE COULD BE A SCATTERED LATE AFTERNOON
THUNDERSTORM AROUND KDIK...OTHERWISE IT LOOKS LIKE THE BEST CHANCE
FOR SHOWERS AND THUNDERSTORMS WILL ENTER THE WEST LATER THIS
EVENING AND SPREAD EAST ACROSS THE AREA...APPROACHING KJMS NEAR
THE END OF THE 18Z TAF PERIOD. THE ONLY SIGNIFICANT CHANGE FROM
THE PREVIOUS FORECAST WAS TO DELAY THE ONSET OF THUNDER ABOUT 3-4
HOURS AT ALL TAF SITES. VFR CONDITIONS EXPECTED THIS AFTERNOON AND
THIS EVENING. DID NOT INTRODUCE MVFR CEILINGS TONIGHT OR SUNDAY
MORNING BUT CERTAINLY COULD SEE AREAS OF MVFR CIGS/VSBYS IN THE
VICINITY OF SHOWERS AND ISOLATED THUNDERSTORMS.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...TWH
LONG TERM...NH
AVIATION...TWH
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
1248 PM CDT SAT AUG 3 2013
.UPDATE...
ISSUED AT 1008 AM CDT SAT AUG 3 2013
STRATIFORM AREA TO NORTH OF NEBRASKA CONVECTION AGAIN CAUSING
ISSUES WITH THE ONGOING FORECAST. MADE AN EARLIER UPDATE FOR
WIDESPREAD LIGHT PRECIP IN THE SOUTHWEST CWA EARLY THIS MORNING...
AND NOW CONSIDERING MORE OF THE LONGER RANGE IMPACTS IN SKYCOVER
AND TEMPS. WITH PARENT CONVECTION NOW UNDERGOING A WEAKENING
CYCLE...WOULD EXPECT THAT STRATIFORM AREA WOULD ALSO START TO
DIMINISH STARTING IN THE NEXT HOUR OR TWO...AND HAVE TRIED TO DRAW
THIS INTO THE HOURLY GRIDS. ALSO COMPLICATING IS THE DRIER AIRMASS
AT LOW LEVELS TO THE EAST...ALL OF WHICH WILL BE ERODING ADVANCING
PRECIP. HRRR HAS THE GENERAL IDEA...BUT FAR TOO EXTENSIVE. SHOULD
GET PRETTY RAGGED BY THE TIME IT STRETCHES INTO NORTHEAST NEBRASKA
BY VERY LATE MORNING...AND MUCH MORE LIKELY TO NOT MAKE IT TO KSUX
WITH ALL ELEMENTS WORKING AGAINST THE AGGRESSIVE EASTWARD PUSH.
ALSO...NOT VERY ENTHUSIASTIC ABOUT MENTION OF THUNDER WITH
ACTIVITY. MUCH MORE LIKELY TO GET AN ISOLATED STORM DEVELOPING
AFTER INITIAL STRATIFORM AREA SLIDES PAST ON THE BACK SIDE ACROSS
THE LOWER BRULE AREA...ABOUT THE ONLY LOCATION TO EXHIBIT ANY
ELEVATED INSTABILITY.
PUSHED BACK DIURNAL RISE QUITE A BIT UNDER THICK CLOUD SHIELD THIS
MORNING...AND KNOCKED BACK HIGHS ALREADY A COUPLE DEGREES IN THE
SOUTHWEST LOCATION...BUT SOMEWHAT CAUTIOUS TO DO MUCH MORE GIVEN
LIKELIHOOD OF LATER DAY PARTIAL CLEARING. PLAN TO SLOW UP THE
RISES A BIT MORE...AND SHAVE PERHAPS ANOTHER DEGREE OR TWO OFF ON
DAYTIME EXPECTATIONS FOR MORE CLOUDY LOCATIONS.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 351 AM CDT SAT AUG 3 2013
CONVECTION FIRING EARLY THIS MORNING ACROSS WESTERN SOUTH DAKOTA ON
THE NOSE OF AN INCREASING LOW LEVEL JET. EXPECT THIS AREA OF STORMS
TO EXPAND SOME THIS MORNING...WITH A SOUTHEAST STORM MOTION.
ELEVATED INSTABILITY REALLY DROPS OFF AS YOU HEAD EAST TOWARDS OUR
CWA. THUS EXPECT ANY STRONGER ACTIVITY TO STAY SOUTH AND WEST INTO
NEBRASKA. HOWEVER COULD SEE SOME LIGHTER RAIN OR POSSIBLY A
THUNDERSTORM ON THE NORTHERN EDGE OF THE COMPLEX MAKE IT INTO THE
SOUTHWEST PORTION OF THE CWA...TOWARDS GREGORY AND CHARLES MIX
COUNTIES...THIS MORNING. OTHERWISE EXPECTING PARTLY TO MOSTLY SUNNY
SKIES OVER THE AREA...WITH INCREASING SUN THE FURTHER NORTHEAST YOU
GET. THINK WE SEE ENOUGH SUN TO REACH NEAR FULL MIXING POTENTIAL
TODAY...HOWEVER THAT WILL STILL LEAVE US SEVERAL DEGREES BELOW
NORMAL..WITH MID AND UPPER 70S COMMON. TONIGHT WILL LIKELY START
MOSTLY CLEAR...WITH INCREASING CLOUDS FROM WEST TO EAST. IT AGAIN
APPEARS LIKELY THAT CONVECTION WILL GET GOING ON THE THE LOW LEVEL
JET WEST OF OUR AREA DURING THE FIRST PART OF THE NIGHT. LOOKS LIKE
A STRONGER WAVE ACCOMPANYING THIS CONVECTION...AND BETTER ANTECEDENT
MOISTURE OVERHEAD. THUS LOOKS LIKE A BETTER CHANCE THAT THIS
THUNDERSTORM ACTIVITY MAKES IT INTO OUR CWA. ALTHOUGH AGAIN ELEVATED
INSTABILITY IS PRETTY MINIMAL...THUS WOULD NOT EXPECT TO SEE ANY
SEVERE WEATHER. TIMING SEEMS TO PUT THE CONVECTION ENTERING OUR
WESTERN CWA A FEW HOURS EITHER SIDE OF 12Z. LOWS WILL RANGE FROM THE
MID 50S EAST WHERE CLOUDS WILL BE LAST TO ARRIVE...TO AROUND 60
WEST.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 351 AM CDT SAT AUG 3 2013
FOR THE DAY ON SUNDAY...ANTICIPATE AFOREMENTIONED CONVECTION TO
SPREAD INTO THE WESTERN PORTIONS OF THE CWA THROUGH THE EARLY PART
OF THE DAY PER LOW LEVEL FORCING VIA THE 850 MB JET...WITH HIGHER
POPS ACROSS OUR NORTHWEST CLOSER TO THE BETTER LIFT SUPPORTED BY MODEL
DIV Q FIELDS. THINK THERE WILL BE A GENERALLY DOWNWARD TREND IN
CONVECTION THROUGH THE DAY AS LOW LEVEL FORCING WEAKENS. ALTHOUGH
850 MB TEMPERATURES WARM A TAD ON SUNDAY...THINK THAT CLOUD
COVER/ASSOCIATED SHOWERS WILL KEEP READINGS DOWN ACROSS THE NORTHERN
TWO THIRDS OF THE CWA...WITH HIGHS TOPPING OUT IN THE LOWER TO MID
70S OVER THAT AREA...TO NEAR 80 THROUGH THE LOWER MISSOURI RIVER
VALLEY.
ON SUNDAY NIGHT THINK THE BETTER CHANCE OF CONVECTION WILL EXIST
OVER OUR NORTHEASTERN AREAS AS A SECONDARY SHORTWAVE DROPS THROUGH
NORTHEASTERN SOUTH DAKOTA INTO SOUTHERN MINNESOTA OVERNIGHT. IT WILL
BE A LITTLE MILDER ON SUNDAY NIGHT IN THE RETURN SOUTHERLY FLOW ON
THE BACKSIDE OF AN EXITING SURFACE RIDGE...WITH LOWS GENERALLY IN
THE LOWER 60S.
WITH SUBSIDENCE BEHIND THE EXITING WAVE...EXPECT A LESSER CHANCE OF
CONVECTION DURING THE DAY ON MONDAY. TEMPERATURES WILL CLIMB A BIT
IN CONTINUED WARMING THERMAL PROFILES AND MORE SUN...WITH HIGHS INTO
THE UPPER 70S TO MID 80S. CONVECTION EXPECTED TO DEVELOP OVER
WESTERN SOUTH DAKOTA ON MONDAY NIGHT COULD PUSH INTO OUR WESTERN
AREAS LATE...THOUGH MODELS OF COURSE DIFFERING ON HOW THIS SCENARIO
EVOLVES. AN EVEN MILDER NIGHT EXPECTED WITH LOWS IN THE LOWER TO MID
60S.
FARTHER INTO THE EXTENDED...MODELS IN FAIRLY DECENT AGREEMENT ON
BRINGING A COLD FRONT THROUGH THE REGION LATER ON TUESDAY...WITH
ADDITIONAL CONVECTION POSSIBLE. DEPENDING ON TIMING...CONVECTIVE
PARAMETERS WOULD SUGGEST THAT SEVERE STORMS WOULD BE POSSIBLE ON
TUESDAY AFTERNOON AND EVENING. AFTER THAT...MODELS IN AGREEMENT ON
OUR AREA BEING IN A NORTHWESTERLY UPPER LEVEL FLOW THROUGH THE
REMAINDER OF THE WEEK AS A BROAD UPPER LEVEL LOW SPINS OVER EASTERN
CANADA/NORTHERN GREAT LAKES REGION. THIS WILL KEEP BELOW NORMAL
TEMPERATURES LOCKED OVER OUR AREA...WITH HIGHS GENERALLY IN THE 70S
AND LOWS IN THE 50S. WITH OBVIOUS MODEL DIFFERENCES THAT FAR
OUT...STUCK WITH CONSENSUS IN TERMS OF PRECIPITATION THROUGH THE
PERIOD...WITH ONLY LOW CHANCES FOR THE END OF NEXT WEEK.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1247 PM CDT SAT AUG 3 2013
VFR CONDITIONS WILL PREVAIL ACROSS THE AREA THROUGH LATE NIGHT...
BEFORE IMPACTS OF CONVECTION PROPAGATING FROM THE WEST AND
NORTHWEST ARRIVE IN THE KHON VICINITY AFTER DAYBREAK. DID INCLUDE
SOME THUNDER WITH PRECIPITATION CHANCES DURING THE MORNING...
BUT MAY EVEN GET SOME PRECIPITATION LINGERING SOMEWHAT LONGER THAN
THE SOMEWHAT RESTRICTED MENTION WINDOW. DID TOSS IN INITIAL
INDICATOR INTO KFSD TAF AS WELL...WITH LOW LEVEL JET SHIFTING
EASTWARD LATE IN THE PERIOD. A FEW PERIODS OF MVFR VISIBILITIES
COULD ACCOMPANY THE SHOWERS/STORMS IN KHON.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
UPDATE...CHAPMAN
SHORT TERM...CHENARD
LONG TERM...JM
AVIATION...CHAPMAN
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
142 PM EDT SAT AUG 3 2013
.SYNOPSIS...
A COLD FRONT WILL MOVE SOUTHEAST THROUGH THE AREA LATE TODAY INTO
TONIGHT...PRECEDED AND ACCOMPANIED BY SHOWERS AND THUNDERSTORMS.
HIGH PRESSURE FOLLOWING THE FRONT WILL BRING DRIER AND COOLER AIR
BACK INTO THE REGION SUNDAY INTO MONDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1225 PM SATURDAY...
MADE A QUICK ADJUSTMENT IN POPS FOR DEVELOPMENT OF CONVECTION
THIS AFTERNOON AHEAD OF SHORTWAVE IN MOIST UNSTABLE AIR. ALSO
MODIFIED TEMPERATURES AND DEW POINTS ACCORDING TO LATEST OBS AND
MODEL TREND. DEW POINTS TEMPERATURES HAVE CLIMB TO AROUND 70
DEGREES ACROSS SOUTHERN PORTIONS OF CWA THIS AFTERNOON. THE COLD
FRONT WILL DROP SOUTHEAST ACROSS THE REGION INTO TONIGHT. MORE
CHANGES LATER THIS AFTERNOON.
AS OF 950 AM EDT SATURDAY...
KFCX 88D LOOP SHOWED SCATTERED SHOWERS TRAVELING EAST ACROSS
CWA THIS MORNING ASSOCIATED WITH ISENTROPIC LIFT. EXPANDED THE LIGHT
POPS TO THE EAST THIS MORNING...AS THEY BATTLE THE DOWNSLOPE FLOW.
RNK WRF ARW SHOWED SHOWERS WEAKENING WITH PROGRESSION EASTWARD.
THIS MORNING 8AM/12Z RNK SOUNDING INDICATED THAT PWATS HAVE
INCREASED TO 1.20 INCH WITH A WEST FLOW.
SHORTWAVE TROF WILL DROP SOUTHEAST TODAY INTO TONIGHT. A COOL FRONT
WILL MOVE INTO AND THROUGH THE BLACKSBURG FORECAST AREA TONIGHT. A
COUPLE OF WEAK BOUNDARIES AHEAD OF THE FRONT MAY COMBINE WITH
LIMITED INSTABILITY TO CREATE WIDELY SCATTERED TO SCATTERED SHOWERS
AND THUNDERSTORMS THIS AFTERNOON INTO THIS EVENING HELP BY CONFLUENCE
ZONE.
NAM AND WRF INDICATED THAT BEST INSTABILITY REMAINS LOCKED UP OVER
SOUTHSIDE VIRGINIA INTO NORTH CENTRAL NORTH CAROLINA WHERE MUCH
DEEPER LOW LEVEL MOISTURE RESIDES IN VICINITY OF OLD FRONT. IF
CLOUD COVER THINS ENOUGH...SCATTERED SHOWERS AND THUNDERSTORMS
COULD DEVELOP BY LATE AFTERNOON IN SOUTHEASTERN PART OF FORECAST
AREA. A STRONGER THUNDERSTORM COULD CONTAIN GUSTY WINDS AND
HEAVY DOWNPOURS.
SHOWERS AND THUNDERSTORMS THIS EVENING INTO TONIGHT WILL DIMINISH
WITH THE LOSS OF SOLAR HEATING AS SHORTWAVE ENERGY REMAINS WELL
NORTH OF US. MADE SOME MINOR ADJUSTMENTS TO POPS...TEMPERATURES
AND CLOUD COVER IN ISC GRIDS.
AS OF 355 AM EDT SATURDAY...
SCATTERED SHOWERS CURRENTLY MOVING EAST OUT OF EASTERN KY AND WV
ON NOSE OF ISENTROPIC LIFT ZONE MAXIMIZED IN 850-700 MILLIBAR
LAYER...AND WILL LIKELY CONTINUE EAST INTO NORTHWESTERN PORTION OF
THE BLACKSBURG FORECAST AREA THROUGH THE DAYBREAK HOURS BEFORE
DISSIPATING EAST OF THE BLUE RIDGE BY MID MORNING AS AREA
ENCOUNTERS INCREASINGLY DOWNSLOPE FLOW. OTHERWISE...EXPECT TO SEE
ANY EARLY MORNING FOG IN MOUNTAIN VALLEYS...AND ACROSS SOUTHSIDE
VA INTO NORTH CENTRAL NC IN VICINITY OF OLD FRONTAL BOUNDARY
RAPIDLY DISSIPATE WITH ONSET OF DAYTIME HEATING.
TRICKY FORECAST FOR REST OF TODAY AS A COMBINATION OF WEATHER
FEATURES COMPETE FOR ATTENTION. WIDESPREAD AREA OF SHOWERS
CURRENTLY OVER OH VALLEY ASSOCIATED WITH FIRST IN SERIES OF SHORT
WAVE TROFS THAT WILL PROGRESSIVELY CARVE OUT UPPER TROF OVER THE
NORTHEASTERN PORTION OF THE NATION THIS WEEKEND...DRIVING COOL
FRONT INTO AND THROUGH THE BLACKSBURG FORECAST AREA TONIGHT. LOCAL
WRF AND HRRR MODELS INDICATING THAT PRECEDING AREA OF SHOWERS MAY
HELP GENERATE AND PUSH OUTFLOW BOUNDARY SOUTHEAST OUT AHEAD OF
THE FRONT INTO NORTHERN THIRD OF THE BLACKSBURG FORECAST AREA THIS
AFTERNOON. DESPITE RATHER LACKLUSTER MID LEVEL INSTABILITY...AND
POTENTIAL OF AT LEAST SOME OFFSET OF INSOLATIVE POTENTIAL DUE TO
LINGERING MID AND HIGH LEVEL CLOUDS...WIDELY SCATTERED TO
SCATTERED SHOWERS/THUNDERSTORMS ARE EXPECTED TO DEVELOP BY/DURING
THE EARLY TO MID AFTERNOON IN ASSOCIATED CONFLUENCE ZONE...
ESPECIALLY NORTH OF HIGHWAY 460...AND ACROSS WESTERN FLANKS OF THE
APPALACHIANS AS WESTERLY UPSLOPING WINDS PROVIDE SOME NEEDED
UPWARD ASSIST.
MUCH BETTER INSTABILITY REMAINS LOCKED UP OVER SOUTHSIDE VA INTO
NORTH CENTRAL NC WHERE MUCH DEEPER LOW LEVEL/TROPICAL MOISTURE
RESIDES IN VICINITY OF OLD FRONT. SHORT RANGE AND MESOSCALE
MODELS HIGHLIGHT THIS AREA FOR ADDITIONAL SCATTERED
SHOWER/THUNDERSTORM DEVELOPMENT...ALTHOUGH ANY NORTHWARD PUSH OF
THIS AIRMASS INTO VA APPEARS UNLIKELY CONSIDERING SLOW VEERING OF
WINDS AS ZONAL FLOW INCREASES OVER AREA.
IN LIGHT OF THE ABOVE...BEST THREAT FOR WIDELY SCATTERED TO
SCATTERED SHOWERS/THUNDERSTORMS TODAY WILL BE ACROSS THE
NORTH...NORTHWEST...AND SOUTHEAST PORTION OF THE BLACKSBURG
FORECAST AREA...WITH RELATIVE MINIMUM (MORE ISOLATED) THREAT FROM
THE FOOTHILLS OF NORTHWEST NC NORTHEAST TOWARD FARMVILLE VA.
SEVERE WEATHER THREAT AT THE PRESENT TIME APPEARS TO BE REMOTE.
LOSS OF DAYTIME HEATING AND LITTLE TO NO DYNAMIC SUPPORT AS SHORT
WAVE ENERGY REMAINS WELL NORTH OF THE BLACKSBURG AREA SHOULD
SUPPORT DEMISE OF LINGERING SHOWER/THUNDERSTORM ACTIVITY IN MOST
AREAS BEFORE MIDNIGHT TONIGHT...BUT WITH A LOW THREAT OF SOME
STRAY SHOWERS REMAINING INTO THE EARLY MORNING HOURS ACROSS THE
SOUTHWESTERN MOUNTAINS WHERE A BIT DEEPER MOISTURE PROFILE WILL
RESIDE AS COLDER AIR FOLDS INTO AREA FROM THE NORTH.
MOS GUIDANCE GENERALLY ACCEPTED FOR THE NEAR TERM PERIOD...WITH
HIGHS TODAY IN THE 70S ACROSS THE HIGHER TERRAIN TO 80S
ELSEWHERE...WITH OVERNIGHT LOWS MAINLY IN THE 60S EXCLUDING SOME
MID TO UPPER 50S IN SOME OF THE DEEPER MOUNTAIN VALLEYS.
&&
.SHORT TERM /SUNDAY THROUGH TUESDAY NIGHT/...
AS OF 430 AM EDT SATURDAY...
A BRIEF AMPLIFICATION OF THE NW FLOW ALOFT WILL ALLOW A FAIRLY
SUBSTANTIAL AREA OF COOL...DRY HIGH PRESSURE TO SPREAD SE ACROSS
THE REGION BEHIND A COLD FRONT WHICH WILL PUSH INTO SOUTH CAROLINA
BEFORE STALLING MONDAY. THIS WILL PROVIDE THE FORECAST AREA WITH
A RESPITE FROM THE INCESSANT SHRA/TSRA ACTIVITY OF RECENT DAYS AND
ALLOW A QUITE DRY AIR MASS TO SPREAD THROUGH THE AREA BY EARLY
MON. ANY REMNANT -SHRA AROUND DAYBREAK SUN...SHOULD DISSIPATE
QUICKLY AND SKIES SHOULD CLEAR EAST OF THE ALLEGHANYS. CANNOT RULE
OUT LINGERING UPSLOPE SC ACROSS SE WV...BUT OVERALL EVEN THOSE
AREAS SHOULD CLEAR OUT BY EVENING.
TEMPS SUN SHOULD BE BELOW NORMAL WEST OF THE ALLEGHANYS...BUT
NEAR NORMAL ACROSS THE PIEDMONT FROM STRONG INSOLATION AND
DOWNSLOPE NW FLOW. MON MORNING SHOULD BE THE COOLEST MORNING OF
THE NEXT SEVEN DAYS AND RIVAL THE RECENT PAST COUPLE OF COOL
SPELLS WHERE MIN TEMPS DIPPED INTO THE UPPER 40S IN DEEPER
MOUNTAIN VALLEYS WITH WIDESPREAD 50S WEST OF THE BLUE
RIDGE...LOWER 60S ACROSS THE PIEDMONT.
FOR TUE...THE FIRST IN A LONG SERIES OF NW FLOW DISTURBANCES
TRACKS ACROSS THE REGION AS A PRONOUNCED BAROCLINIC ZONE BEGINS TO
SET UP ACROSS THE REGION FROM NW-SE FROM THE OHIO VALLEY TOWARD
THE MID-ATLANTIC...BEGINNING WHAT SHOULD BE A 3-5 DAY PERIOD OF
QUITE ACTIVE CONVECTIVE WEATHER. FOR TUE...SFC MOISTURE WILL JUST
BE RECOVERING...SO NOT EXPECTING AN OVERLY ACTIVE CONVECTIVE DAY
JUST YET. THE MON SFC HIGH WILL MOVE TO A POSITION OFF THE MID-
ATLANTIC COAST AND ALLOW A WEAK WEDGE SITUATION TO EVOLVE EAST OF
THE BLUE RIDGE. FOR NOW...HAVE ADVERTISED LOW CHC POPS MOST
AREAS...BUT THE BEST THREAT FOR PCPN APPEARS TO BE EAST OF OR NEAR
THE ALLEGHANYS AT THIS TIME WHERE LOW-LEVEL MOISTURE CONVERGENCE
AND SFC TD IS MAXIMIZED AND DIFFERENTIAL HEATING MAY HELP SPARK
INITIAL CONVECTION DURING THE AFTERNOON. MAX/MIN TEMPS WILL BEGIN
TO RECOVER FROM THE MON COOL SPELL AND SHOULD BE CLOSER TO
NORMAL...EXCEPT STILL SLIGHTLY BELOW NORMAL IN THE FAR N-NW PART
OF THE CWA.
&&
.LONG TERM /WEDNESDAY THROUGH FRIDAY/...
AS OF 445 AM EDT SATURDAY...
AS NOTED THE PAST SEVERAL DAYS...THIS PERIOD LOOKS TO BE QUITE
ACTIVE WITH REGARD TO CONVECTION. THE FLOW WILL TREND TOWARD AN
INCREASINGLY ZONAL FLOW WITH A SERIES OF EMBEDDED DISTURBANCES
ALOFT. A WEAK COLD FRONT WILL BEGIN TO ENTER THE NW PART OF THE
CWA BY THU...THEN ATTEMPT TO PUSH SLOWLY SOUTHEASTWARD THU-FRI.
HOW FAR S-SE THE FRONT MOVES BEFORE STALLING IS HIGHLY
QUESTIONABLE GIVEN THE INCREASING ZONAL FLOW IN PLACE AND A
SUBTROPICAL RIDGE BUILDING ACROSS THE SE STATES. BOTH THE GFS AND
ECMWF TRY TO PUSH THE FRONT COMPLETELY SOUTH OF OUR CWA BY
SATURDAY AS IT STRENGTHENS THE NW FLOW JUST ENOUGH TO DO SO...BUT
AS NOTED...THAT IS SOMEWHAT DOUBTFUL.
AT ANY RATE...WED-THU LOOK QUITE ACTIVE AND
PROBLEMATIC...ESPECIALLY IN TERMS OF FLASH FLOOD POTENTIAL. PWATS
REACH OR EXCEED 2.0 INCHES ACROSS MUCH OF THE CWA WED- THU
AFTERNOON. THIS COMBINED WITH PERIODIC AMPLE UPPER SUPPORT FROM
EMBEDDED SHORT WAVES AND THE VERY WET ANTECEDENT CONDITIONS WILL
HAVE TO BE WATCHED VERY CAREFULLY. WITH A NEARLY STALLED OR QUASI-
STATIONARY FRONTAL BOUNDARY DRAPED ACROSS THE REGION AND FAVORABLE
SUPPORT...TRAINING OF SHRA/TSRA ACTIVITY APPEARS LIKELY.
FURTHERMORE...INSTABILITY LOOKS QUITE HEALTHY WITH CAPES REACHING
2000 J/KG OR GREATER WED AND THU AFTERNOON ACROSS MUCH OF THE CWA.
THUS...A FEW STRONG TO SEVERE THUNDERSTORMS ALSO APPEAR LIKELY.
HAVE INTRODUCED THE MENTION OF HEAVY RAIN TO THE ZFP FOR THESE
PERIODS AND WILL ALSO CONTINUE TO INCLUDE THE THREAT OF HEAVY RAIN
AND ISOLATED SEVERE IN THE HWO.
HUMIDITY LEVELS WILL BE QUITE HIGH THROUGH THE EXTENDED
PERIODS...SO THERE WILL BE LITTLE COOLING AT NIGHT. BY THE SAME
TOKEN...MAX TEMPS SHOULD REMAIN NEAR NORMAL...PERHAPS SLIGHTLY BELOW
IN AREAS THAT HAVE ENOUGH CLOUD COVER/PCPN TO LIMIT HEATING.
NONETHELESS...IT WILL BE QUITE MUGGY AND MUCH MORE UNCOMFORTABLE
THAN THE BEGINNING OF THE WEEK.
&&
.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
AS OF 130 PM EDT SATURDAY...
A COLD FRONT WILL DROP SOUTHEAST THROUGH THE AREA TONIGHT
INTO SUNDAY. SCATTERED MVFR SHOWERS AND THUNDERSTORMS
WILL DEVELOP ALONG AND AHEAD OF THE FRONT THIS AFTERNOON INTO
TONIGHT. THE FOCUS FOR CONVECTION FOR THE NEXT COUPLE OF HOURS
WILL BE ALONG A MOISTURE CONVERGENCE ZONE ACROSS SOUTHEAST
PORTIONS OF CWA.
EXPECT A BAND OF CONVECTION TO REDEVELOP ACROSS THE NORTH AFTER
19Z AND TRAVEL SOUTHEAST THIS EVENING INTO TONIGHT.
OVERNIGHT...A FEW -SHRA MAY REDEVELOP ACROSS WV AND MOVE TOWARD
THE NEW RIVER/ROANOKE VALLEY BEFORE DISSIPATING.
MOSTLY VFR CIGS EXPECTED WITH THIS ACTIVITY AS WELL. THE
EXCEPTION TO CIGS OVERNIGHT WILL BE IN UPSLOPE AREAS OF SE
WV...WHERE MVFR CIGS/MVFR VSBYS COULD DEVELOP FROM BLF-
LWB...ESPECIALLY BLF AS TYPICAL WITH THIS SCENARIO.
WINDS WSW 5-10KTS THIS AFTERNOON...BECOMING WNW-NW BEHIND THE
FRONT OVERNIGHT AT SPEEDS OF 5-7KTS.
MEDIUM TO HIGH CONFIDENCE IN CIGS THROUGH TAF VALID PERIOD.
MEDIUM TO HIGH CONFIDENCE IN VSBYS THROUGH TAF VALID PERIOD.
HIGH CONFIDENCE IN WIND SPD/DIR THROUGH TAF VALID PERIOD.
MEDIUM CONFIDENCE IN TSRA POTENTIAL THIS AFTERNOON/TONIGHT.
EXTENDED AVIATION DISCUSSION...
VFR CONDITIONS EXPECTED SUN-MON...OUTSIDE SOME EARLY MORNING MVFR
CIGS SE WV SITES. SPOTTY AFTERNOON CONVECTION POSSIBLE TUE
AFTERNOON...MAINLY LYH/DAN/ROA. WEDNESDAY THROUGH FRIDAY BRINGS
WIDESPREAD CONVECTION BACK TO THE CWA...WITH ATTENDANT LOWER
CIGS/VSBYS AS TROPICAL MOISTURE RETURNS TO THE AREA AND A QUASI-
STATIONARY FRONTAL BOUNDARY DRIFTS SLOWLY SOUTHWARD THROUGH THE
AREA.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...WERT
NEAR TERM...KK/WERT
SHORT TERM...RAB
LONG TERM...RAB/WP
AVIATION...KK/RAB
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
1231 PM EDT SAT AUG 3 2013
.SYNOPSIS...
A COLD FRONT WILL MOVE SOUTHEAST THROUGH THE AREA LATE TODAY INTO
TONIGHT...PRECEDED AND ACCOMPANIED BY SHOWERS AND THUNDERSTORMS.
HIGH PRESSURE FOLLOWING THE FRONT WILL BRING DRIER AND COOLER AIR
BACK INTO THE REGION SUNDAY INTO MONDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1225 PM SATURDAY...
MADE A QUICK ADJUSTMENT IN POPS FOR DEVELOPMENT OF CONVECTION
THIS AFTERNOON AHEAD OF SHORTWAVE IN MOIST UNSTABLE AIR. ALSO
MODIFIED TEMPERATURES AND DEW POINTS ACCORDING TO LATEST OBS AND
MODEL TREND. DEW POINTS TEMPERATURES HAVE CLIMB TO AROUND 70
DEGREES ACROSS SOUTHERN PORTIONS OF CWA THIS AFTERNOON. THE COLD
FRONT WILL DROP SOUTHEAST ACROSS THE REGION INTO TONIGHT. MORE
CHANGES LATER THIS AFTERNOON.
AS OF 950 AM EDT SATURDAY...
KFCX 88D LOOP SHOWED SCATTERED SHOWERS TRAVELING EAST ACROSS
CWA THIS MORNING ASSOCIATED WITH ISENTROPIC LIFT. EXPANDED THE LIGHT
POPS TO THE EAST THIS MORNING...AS THEY BATTLE THE DOWNSLOPE FLOW.
RNK WRF ARW SHOWED SHOWERS WEAKENING WITH PROGRESSION EASTWARD.
THIS MORNING 8AM/12Z RNK SOUNDING INDICATED THAT PWATS HAVE
INCREASED TO 1.20 INCH WITH A WEST FLOW.
SHORTWAVE TROF WILL DROP SOUTHEAST TODAY INTO TONIGHT. A COOL FRONT
WILL MOVE INTO AND THROUGH THE BLACKSBURG FORECAST AREA TONIGHT. A
COUPLE OF WEAK BOUNDARIES AHEAD OF THE FRONT MAY COMBINE WITH
LIMITED INSTABILITY TO CREATE WIDELY SCATTERED TO SCATTERED SHOWERS
AND THUNDERSTORMS THIS AFTERNOON INTO THIS EVENING HELP BY CONFLUENCE
ZONE.
NAM AND WRF INDICATED THAT BEST INSTABILITY REMAINS LOCKED UP OVER
SOUTHSIDE VIRGINIA INTO NORTH CENTRAL NORTH CAROLINA WHERE MUCH
DEEPER LOW LEVEL MOISTURE RESIDES IN VICINITY OF OLD FRONT. IF
CLOUD COVER THINS ENOUGH...SCATTERED SHOWERS AND THUNDERSTORMS
COULD DEVELOP BY LATE AFTERNOON IN SOUTHEASTERN PART OF FORECAST
AREA. A STRONGER THUNDERSTORM COULD CONTAIN GUSTY WINDS AND
HEAVY DOWNPOURS.
SHOWERS AND THUNDERSTORMS THIS EVENING INTO TONIGHT WILL DIMINISH
WITH THE LOSS OF SOLAR HEATING AS SHORTWAVE ENERGY REMAINS WELL
NORTH OF US. MADE SOME MINOR ADJUSTMENTS TO POPS...TEMPERATURES
AND CLOUD COVER IN ISC GRIDS.
AS OF 355 AM EDT SATURDAY...
SCATTERED SHOWERS CURRENTLY MOVING EAST OUT OF EASTERN KY AND WV
ON NOSE OF ISENTROPIC LIFT ZONE MAXIMIZED IN 850-700 MILLIBAR
LAYER...AND WILL LIKELY CONTINUE EAST INTO NORTHWESTERN PORTION OF
THE BLACKSBURG FORECAST AREA THROUGH THE DAYBREAK HOURS BEFORE
DISSIPATING EAST OF THE BLUE RIDGE BY MID MORNING AS AREA
ENCOUNTERS INCREASINGLY DOWNSLOPE FLOW. OTHERWISE...EXPECT TO SEE
ANY EARLY MORNING FOG IN MOUNTAIN VALLEYS...AND ACROSS SOUTHSIDE
VA INTO NORTH CENTRAL NC IN VICINITY OF OLD FRONTAL BOUNDARY
RAPIDLY DISSIPATE WITH ONSET OF DAYTIME HEATING.
TRICKY FORECAST FOR REST OF TODAY AS A COMBINATION OF WEATHER
FEATURES COMPETE FOR ATTENTION. WIDESPREAD AREA OF SHOWERS
CURRENTLY OVER OH VALLEY ASSOCIATED WITH FIRST IN SERIES OF SHORT
WAVE TROFS THAT WILL PROGRESSIVELY CARVE OUT UPPER TROF OVER THE
NORTHEASTERN PORTION OF THE NATION THIS WEEKEND...DRIVING COOL
FRONT INTO AND THROUGH THE BLACKSBURG FORECAST AREA TONIGHT. LOCAL
WRF AND HRRR MODELS INDICATING THAT PRECEDING AREA OF SHOWERS MAY
HELP GENERATE AND PUSH OUTFLOW BOUNDARY SOUTHEAST OUT AHEAD OF
THE FRONT INTO NORTHERN THIRD OF THE BLACKSBURG FORECAST AREA THIS
AFTERNOON. DESPITE RATHER LACKLUSTER MID LEVEL INSTABILITY...AND
POTENTIAL OF AT LEAST SOME OFFSET OF INSOLATIVE POTENTIAL DUE TO
LINGERING MID AND HIGH LEVEL CLOUDS...WIDELY SCATTERED TO
SCATTERED SHOWERS/THUNDERSTORMS ARE EXPECTED TO DEVELOP BY/DURING
THE EARLY TO MID AFTERNOON IN ASSOCIATED CONFLUENCE ZONE...
ESPECIALLY NORTH OF HIGHWAY 460...AND ACROSS WESTERN FLANKS OF THE
APPALACHIANS AS WESTERLY UPSLOPING WINDS PROVIDE SOME NEEDED
UPWARD ASSIST.
MUCH BETTER INSTABILITY REMAINS LOCKED UP OVER SOUTHSIDE VA INTO
NORTH CENTRAL NC WHERE MUCH DEEPER LOW LEVEL/TROPICAL MOISTURE
RESIDES IN VICINITY OF OLD FRONT. SHORT RANGE AND MESOSCALE
MODELS HIGHLIGHT THIS AREA FOR ADDITIONAL SCATTERED
SHOWER/THUNDERSTORM DEVELOPMENT...ALTHOUGH ANY NORTHWARD PUSH OF
THIS AIRMASS INTO VA APPEARS UNLIKELY CONSIDERING SLOW VEERING OF
WINDS AS ZONAL FLOW INCREASES OVER AREA.
IN LIGHT OF THE ABOVE...BEST THREAT FOR WIDELY SCATTERED TO
SCATTERED SHOWERS/THUNDERSTORMS TODAY WILL BE ACROSS THE
NORTH...NORTHWEST...AND SOUTHEAST PORTION OF THE BLACKSBURG
FORECAST AREA...WITH RELATIVE MINIMUM (MORE ISOLATED) THREAT FROM
THE FOOTHILLS OF NORTHWEST NC NORTHEAST TOWARD FARMVILLE VA.
SEVERE WEATHER THREAT AT THE PRESENT TIME APPEARS TO BE REMOTE.
LOSS OF DAYTIME HEATING AND LITTLE TO NO DYNAMIC SUPPORT AS SHORT
WAVE ENERGY REMAINS WELL NORTH OF THE BLACKSBURG AREA SHOULD
SUPPORT DEMISE OF LINGERING SHOWER/THUNDERSTORM ACTIVITY IN MOST
AREAS BEFORE MIDNIGHT TONIGHT...BUT WITH A LOW THREAT OF SOME
STRAY SHOWERS REMAINING INTO THE EARLY MORNING HOURS ACROSS THE
SOUTHWESTERN MOUNTAINS WHERE A BIT DEEPER MOISTURE PROFILE WILL
RESIDE AS COLDER AIR FOLDS INTO AREA FROM THE NORTH.
MOS GUIDANCE GENERALLY ACCEPTED FOR THE NEAR TERM PERIOD...WITH
HIGHS TODAY IN THE 70S ACROSS THE HIGHER TERRAIN TO 80S
ELSEWHERE...WITH OVERNIGHT LOWS MAINLY IN THE 60S EXCLUDING SOME
MID TO UPPER 50S IN SOME OF THE DEEPER MOUNTAIN VALLEYS.
&&
.SHORT TERM /SUNDAY THROUGH TUESDAY NIGHT/...
AS OF 430 AM EDT SATURDAY...
A BRIEF AMPLIFICATION OF THE NW FLOW ALOFT WILL ALLOW A FAIRLY
SUBSTANTIAL AREA OF COOL...DRY HIGH PRESSURE TO SPREAD SE ACROSS
THE REGION BEHIND A COLD FRONT WHICH WILL PUSH INTO SOUTH CAROLINA
BEFORE STALLING MONDAY. THIS WILL PROVIDE THE FORECAST AREA WITH
A RESPITE FROM THE INCESSANT SHRA/TSRA ACTIVITY OF RECENT DAYS AND
ALLOW A QUITE DRY AIR MASS TO SPREAD THROUGH THE AREA BY EARLY
MON. ANY REMNANT -SHRA AROUND DAYBREAK SUN...SHOULD DISSIPATE
QUICKLY AND SKIES SHOULD CLEAR EAST OF THE ALLEGHANYS. CANNOT RULE
OUT LINGERING UPSLOPE SC ACROSS SE WV...BUT OVERALL EVEN THOSE
AREAS SHOULD CLEAR OUT BY EVENING.
TEMPS SUN SHOULD BE BELOW NORMAL WEST OF THE ALLEGHANYS...BUT
NEAR NORMAL ACROSS THE PIEDMONT FROM STRONG INSOLATION AND
DOWNSLOPE NW FLOW. MON MORNING SHOULD BE THE COOLEST MORNING OF
THE NEXT SEVEN DAYS AND RIVAL THE RECENT PAST COUPLE OF COOL
SPELLS WHERE MIN TEMPS DIPPED INTO THE UPPER 40S IN DEEPER
MOUNTAIN VALLEYS WITH WIDESPREAD 50S WEST OF THE BLUE
RIDGE...LOWER 60S ACROSS THE PIEDMONT.
FOR TUE...THE FIRST IN A LONG SERIES OF NW FLOW DISTURBANCES
TRACKS ACROSS THE REGION AS A PRONOUNCED BAROCLINIC ZONE BEGINS TO
SET UP ACROSS THE REGION FROM NW-SE FROM THE OHIO VALLEY TOWARD
THE MID-ATLANTIC...BEGINNING WHAT SHOULD BE A 3-5 DAY PERIOD OF
QUITE ACTIVE CONVECTIVE WEATHER. FOR TUE...SFC MOISTURE WILL JUST
BE RECOVERING...SO NOT EXPECTING AN OVERLY ACTIVE CONVECTIVE DAY
JUST YET. THE MON SFC HIGH WILL MOVE TO A POSITION OFF THE MID-
ATLANTIC COAST AND ALLOW A WEAK WEDGE SITUATION TO EVOLVE EAST OF
THE BLUE RIDGE. FOR NOW...HAVE ADVERTISED LOW CHC POPS MOST
AREAS...BUT THE BEST THREAT FOR PCPN APPEARS TO BE EAST OF OR NEAR
THE ALLEGHANYS AT THIS TIME WHERE LOW-LEVEL MOISTURE CONVERGENCE
AND SFC TD IS MAXIMIZED AND DIFFERENTIAL HEATING MAY HELP SPARK
INITIAL CONVECTION DURING THE AFTERNOON. MAX/MIN TEMPS WILL BEGIN
TO RECOVER FROM THE MON COOL SPELL AND SHOULD BE CLOSER TO
NORMAL...EXCEPT STILL SLIGHTLY BELOW NORMAL IN THE FAR N-NW PART
OF THE CWA.
&&
.LONG TERM /WEDNESDAY THROUGH FRIDAY/...
AS OF 445 AM EDT SATURDAY...
AS NOTED THE PAST SEVERAL DAYS...THIS PERIOD LOOKS TO BE QUITE
ACTIVE WITH REGARD TO CONVECTION. THE FLOW WILL TREND TOWARD AN
INCREASINGLY ZONAL FLOW WITH A SERIES OF EMBEDDED DISTURBANCES
ALOFT. A WEAK COLD FRONT WILL BEGIN TO ENTER THE NW PART OF THE
CWA BY THU...THEN ATTEMPT TO PUSH SLOWLY SOUTHEASTWARD THU-FRI.
HOW FAR S-SE THE FRONT MOVES BEFORE STALLING IS HIGHLY
QUESTIONABLE GIVEN THE INCREASING ZONAL FLOW IN PLACE AND A
SUBTROPICAL RIDGE BUILDING ACROSS THE SE STATES. BOTH THE GFS AND
ECMWF TRY TO PUSH THE FRONT COMPLETELY SOUTH OF OUR CWA BY
SATURDAY AS IT STRENGTHENS THE NW FLOW JUST ENOUGH TO DO SO...BUT
AS NOTED...THAT IS SOMEWHAT DOUBTFUL.
AT ANY RATE...WED-THU LOOK QUITE ACTIVE AND
PROBLEMATIC...ESPECIALLY IN TERMS OF FLASH FLOOD POTENTIAL. PWATS
REACH OR EXCEED 2.0 INCHES ACROSS MUCH OF THE CWA WED- THU
AFTERNOON. THIS COMBINED WITH PERIODIC AMPLE UPPER SUPPORT FROM
EMBEDDED SHORT WAVES AND THE VERY WET ANTECEDENT CONDITIONS WILL
HAVE TO BE WATCHED VERY CAREFULLY. WITH A NEARLY STALLED OR QUASI-
STATIONARY FRONTAL BOUNDARY DRAPED ACROSS THE REGION AND FAVORABLE
SUPPORT...TRAINING OF SHRA/TSRA ACTIVITY APPEARS LIKELY.
FURTHERMORE...INSTABILITY LOOKS QUITE HEALTHY WITH CAPES REACHING
2000 J/KG OR GREATER WED AND THU AFTERNOON ACROSS MUCH OF THE CWA.
THUS...A FEW STRONG TO SEVERE THUNDERSTORMS ALSO APPEAR LIKELY.
HAVE INTRODUCED THE MENTION OF HEAVY RAIN TO THE ZFP FOR THESE
PERIODS AND WILL ALSO CONTINUE TO INCLUDE THE THREAT OF HEAVY RAIN
AND ISOLATED SEVERE IN THE HWO.
HUMIDITY LEVELS WILL BE QUITE HIGH THROUGH THE EXTENDED
PERIODS...SO THERE WILL BE LITTLE COOLING AT NIGHT. BY THE SAME
TOKEN...MAX TEMPS SHOULD REMAIN NEAR NORMAL...PERHAPS SLIGHTLY BELOW
IN AREAS THAT HAVE ENOUGH CLOUD COVER/PCPN TO LIMIT HEATING.
NONETHELESS...IT WILL BE QUITE MUGGY AND MUCH MORE UNCOMFORTABLE
THAN THE BEGINNING OF THE WEEK.
&&
.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
AS OF 730 AM EDT SATURDAY...
FIRST BAND OF -SHRA ASSOCIATED WITH UPSTREAM TROUGH/FRONTAL SYSTEM
HAS ALREADY PASSED THROUGH THE CWA. ONLY BLF REPORTED -RA AND A
TRACE OF PCPN...AS EXPECTED MUCH WOULD BE LOST BECAUSE OF
DOWNSLOPE EAST OF THE ALLEGHANYS. MAIN FRONTAL SYSTEM STILL BACK
TO THE NORTH W-E ACROSS CENTRAL OH TO CENTRAL PA. SYNOPTIC SCALE
MODELS SHOW LITTLE PCPN MAKING INTO OR CWA UNTIL LATE
AFTERNOON/EVENING AND EVEN SOME OVERNIGHT INTO EARLY SUN. SFC-BL
MOISTURE IS LACKING...SO FEEL THIS SYSTEM OVERALL WILL BE QUITE
LACKLUSTER FOR OUR CWA. INSTABILITY IS LACKING...SO HAVE REMOVED
MENTION OF VCTS EXCEPT FOR LYH AND DAN WHERE BETTER HEATING AND
INSTABILITY COULD BE REALIZED BY AFTERNOON. OTHERWISE...HAVE JUST
INCLUDED VCSH FOR NOW. CIGS SHOULD REMAIN VFR FOR THE MOST PART
THROUGHOUT THE DAY AT ALL SITES. ANY EARLY MORNING FOG WILL
DISSIPATE QUICKLY AFTER DAYBREAK...AND OVERALL THERE IS VERY
LITTLE THIS MORNING ANYWAY BECAUSE OF THE EXTENSIVE MID/HIGH
CLOUDS STREAMING ACROSS THE REGION. BULK OF ANY SHRA ACTIVITY
SHOULD PASS THROUGH THE CWA IN THE 20Z NORTH TO 04Z SOUTH...WITH
VERY LITTLE EXPECTED SW AREAS. OVERNIGHT...A FEW -SHRA MAY DEVELOP
ACROSS WV AND MOVE TOWARD THE NEW RIVER/ROANOKE VALLEY BEFORE
DISSIPATING. MOSTLY VFR CIGS EXPECTED WITH THIS ACTIVITY AS WELL.
THE EXCEPTION TO CIGS OVERNIGHT WILL BE IN UPSLOPE AREAS OF SE
WV...WHERE MVFR CIGS/MVFR VSBYS COULD DEVELOP FROM BLF-
LWB...ESPECIALLY BLF AS TYPICAL WITH THIS SCENARIO. WINDS WSW
5-8KTS TODAY...BECOMING WNW-NW BEHIND THE FRONT OVERNIGHT AT
SPEEDS OF 5-7KTS.
MEDIUM TO HIGH CONFIDENCE IN CIGS THROUGH TAF VALID PERIOD.
MEDIUM TO HIGH CONFIDENCE IN VSBYS THROUGH TAF VALID PERIOD.
HIGH CONFIDENCE IN WIND SPD/DIR THROUGH TAF VALID PERIOD.
MEDIUM TO HIGH CONFIDENCE IN LIMITED TSRA POTENTIAL THIS
AFTERNOON/EVENING.
EXTENDED AVIATION DISCUSSION...
VFR CONDITIONS EXPECTED SUN-MON...OUTSIDE SOME EARLY MORNING MVFR
CIGS SE WV SITES. SPOTTY AFTERNOON CONVECTION POSSIBLE TUE
AFTERNOON...MAINLY LYH/DAN/ROA. WEDNESDAY THROUGH FRIDAY BRINGS
WIDESPREAD CONVECTION BACK TO THE CWA...WITH ATTENDANT LOWER
CIGS/VSBYS AS TROPICAL MOISTURE RETURNS TO THE AREA AND A QUASI-
STATIONARY FRONTAL BOUNDARY DRIFTS SLOWLY SOUTHWARD THROUGH THE
AREA.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...WERT
NEAR TERM...KK/WERT
SHORT TERM...RAB
LONG TERM...RAB/WP
AVIATION...RAB/WERT
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
447 PM MDT SAT AUG 3 2013
.UPDATE...
ISSUED AT 344 PM MDT SAT AUG 3 2013
LONG TRACKED SEVERE THUNDERSTORM CONTINUES TO HOLD TOGETHER AND
MOVE NORTH INTO NORTHERN LARAMIE COUNTY. WENT AHEAD AND ADDED
PLATTE AND GOSHEN COUNTIES TO THE TORNADO WATCH AS THIS STORM
COULD PRODUCE SEVERE THUNDERSTORMS THERE. PLUS THE ENVIRONMENT IS
PROBABLY BETTER UP THERE FOR MORE WIDESPREAD THUNDERSTORM
DEVELOPMENT. UPDATES HAVE BEEN SENT.
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT)
ISSUED AT 300 PM MDT SAT AUG 3 2013
FORECAST CHALLENGES DEAL WITH THUNDERSTORM TIMING AND LOCATION OF
SEVERE THUNDERSTORMS THIS AFTERNOON THROUGH EVENING HOURS.
CURRENTLY...BOUNDARY LAYING ALONG THE LARAMIE RANGE EARLY THIS
AFTERNOON...SEPARATING FAIRLY DRY AIR TO THE WEST FROM REALLY
MOIST AIR TO THE EAST. DEWPOINTS IN LARAMIE IN THE MID 30S...HERE
AT CHEYENNE WE ARE SEEING UPPER 50S AND OUT BY SIDNEY...MID 60
DEWPOINTS. STRATUS HAS BEEN SLOW TO BREAK UP LATE THIS
MORNING/EARLY THIS AFTERNOON. STILL GETTING REPORTS OF STRATUS IN
THE PANHANDLE AND AS FAR WEST AS TORRINGTON. CHEYENNE HAS REMAINED
UNDER MOSTLY SUNNY SKIES AND CUMULUS HAS BEGUN TO BUILD OVER THE
SOUTHERN LARAMIE RANGE...EXTENDING SOUTH INTO THE MOUNTAINS OF
COLORADO. GETTING OBSERVED LIGHTNING STRIKES OVER CENTRAL
COLORADO...BUT SO FAR...THE CHEYENNE CWFA HAS REMAINED PRETTY MUCH
ECHO FREE. MONSOONAL MOISTURE CONTINUES TO MOVE INTO SOUTH CENTRAL
WYOMING ON WATER VAPOR IMAGERY...MAINLY OVER SOUTHERN CARBON AND
ALBANY COUNTIES THROUGH THE MORNING HOURS.
DO BELIEVE ITS ONLY A MATTER OF TIME FOR CONVECTION TO INITIATE
THIS AFTERNOON. LATEST SPC MESOANALIST PAGE SHOWING SURFACE BASED CAPE
VALUES INCREASING TO AROUND 3500 J/KG JUST SOUTH OF THE CWFA IN
COLORADO WITH AROUND 2500 TO 3000 J/KG JUST NUDGING INTO THE SOUTH
LARAMIE RANGE. STILL SEEING SOME CONVECTIVE INHIBITION EAST OF
CHEYENNE...SPREADING NORTH AND EAST. SPC MESOANALYST PAGE SHOWING
STILL AROUND 100-150 J/KG CONVECTIVE INHIBITION FOR THESE AREAS.
CURRENTLY THINKING AND THIS IS BACKED UP BY LATEST HRRR FORECASTS
IS THAT CONVECTION WILL INITIATE JUST WEST OF CHEYENNE...THEN
SLOWLY SPREAD EAST AND NORTH AS THE CAP ERODES.
MAIN THREATS WITH THUNDERSTORMS TODAY LOOKS TO BE LARGE HAIL AND
DAMAGING WINDS. BULK SHEAR ON THE ORDER OF 40 TO 45KTS. BUT LATER
THIS AFTERNOON...NAM SOUNDINGS ARE SHOWING HELICITY VALUES
INCREASING ABOVE 200 M2/S2 FOR CHEYENNE AND THE SOUTHERN
PANHANDLE...SO CAN NOT RULE OUT SOME TORNADIC SUPERCELLS LATE THIS
AFTERNOON AND EARLY EVENING. LCLS PRETTY LOW...WITH NAM FORECASTING
ANYWHERE FROM 2K TO 3K AGL. FINALLY...HEAVY RAIN IS A CONCERN WITH
PWATS CLIMBING TO OVER 1 INCH HERE AT CHEYENNE AND 1.4 INCHES OUT
BY SIDNEY. STORM MOTIONS ARE FAIRLY SLOW...GENERALLY OUT OF THE
WEST AT LESS THAN 10KTS...SO WE COULD BE LOOKING AT A FLASH FLOOD
THREAT AS WELL IN AREAS THAT SEE TRAINING STORMS. STORMS SHOULD
CONTINUE INTO THE MID TO LATE EVENING HOURS...SPREADING INTO THE
PANHANDLE BY 6 PM OR SO TONIGHT.
FOR SUNDAY...MODELS INDICATING A REPEAT OF TODAYS WEATHER WITH
POSSIBLY CONVECTION FURTHER EAST INTO THE PANHANDLE INITIALLY.
SEVERE THUNDERSTORMS LOOK MORE OUT OVER THE PANHANDLE SUNDAY VS
INITIATING HERE IN SOUTHEAST WYOMING.
.LONG TERM...(TUESDAY THROUGH SATURDAY)
ISSUED AT 320 PM MDT SAT AUG 3 2013
MAIN FORECAST CONCERN THROUGH NEXT WEEK WILL BE A STRONG MID
SUMMER COLD FRONT PUSHING ACROSS THE GREAT PLAINS AND INTO THE
FORECAST AREA...AS THE DEEP 543DM UPPER LEVEL LOW SETTLES OVER
SOUTHERN CANADA NEAR THE GREAT LAKES REGION. THIS IS PRETTY
UNUSUAL FOR THIS TIME OF THE YEAR...ALTHOUGH THE ROCKY MOUNTAIN
REGION WILL NOT SEE THE MAJORITY OF THIS COOLER AIR. MODELS SHOW
THIS FRONT QUICKLY MOVING ACROSS THE AREA TUESDAY AND TUESDAY
EVENING WITH HIGH TEMPERATURES AROUND 10 TO 15 DEGREES COOLER ON
WEDNESDAY AND THURSDAY. WITH SUBTROPICAL MONSOON MOISTURE IN
PLACE...A DAILY CHANCE OF SHOWERS AND THUNDERSTORMS IS ANTICIPATED
ACROSS MOST OF THE FORECAST AREA. THE BEST CHANCE WILL REMAIN OVER
THE MOUNTAINS AND ALONG/EAST OF THE LARAMIE RANGE...PRIMARILY FROM
MID AFTERNOON THROUGH EARLY IN THE EVENING. SOME OF THESE SHOWERS
MAY CONTINUE INTO THE OVERNIGHT HOURS...ESPECIALLY WEDNESDAY AND
THURSDAY NIGHT.
&&
.AVIATION...(FOR THE 00Z TAF ISSUANCE)
SHOWERS AND TSTORMS WILL CONTINUE OVER SOUTHEAST WYOMING. LOW
CONFIDENCE IN TSTORMS ACROSS WESTERN NEBRASKA DUE TO ONGOING FOG AND
LOW CIGS...SO TOOK VCTS OUT OF MOST WESTERN NEBRASKA TERMINALS OR
STARTED VCTS LATER THIS EVENING. STORMS THAT OCCUR NEAR THE WY/NE
BORDER ARE CAPABLE OF PRODUCING LARGE HAIL AS WELL. TSTORMS WILL
DISSIPATE LATE TONIGHT...BUT WITH MOIST SOUTHERLY FLOW REMAINING
OVER THE AREA EXPECT PATCHY FOG AND LOW CIGS BELOW 1K FEET AGL TO
CONTINUE ACROSS THE HIGH PLAINS INTO WESTERN NEBRASKA THROUGH
TONIGHT.
&&
.FIRE WEATHER...
ISSUED AT 300 PM MDT SAT AUG 3 2013
LIGHT WINDS AND MONSOONAL MOISTURE SHOULD KEEP FIRE WEATHER ISSUES
AT BAY FOR TODAY AND SUNDAY. AREAS EAST OF THE LARAMIE RANGE
SHOULD SEE CONTINUED GOOD CHANCES AT WETTING RAINS...HIGH
HUMIDITIES AND EASTERLY UPSLOPING WINDS. AREAS WEST WILL SEE DRIER
CONDITIONS WITH AFTERNOON HUMIDITIES FALLING INTO MID TEENS.
FORTUNATELY...WINDS SHOULD STAY LIGHT OUT THAT WAY KEEPING FIRE
WEATHER CONCERNS MINIMAL. BY MONDAY...SURFACE HIGH PRESSURE MOVING
INTO NORTH CENTRAL COLORADO WILL RE-ESTABLISH WESTERLY WINDS WITH
DRIER AIR FILTERING IN TO AREAS EAST OF THE LARAMIE RANGE. WINDS
WILL REMAIN LIGHT THOUGH...WHICH WILL KEEP FIRE WEATHER MINIMIZED.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&
$$
UPDATE...CLAYCOMB
SHORT TERM...CLAYCOMB
LONG TERM...TJT
AVIATION...TJT
FIRE WEATHER...CLAYCOMB
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
347 PM MDT SAT AUG 3 2013
.UPDATE...
ISSUED AT 344 PM MDT SAT AUG 3 2013
LONG TRACKED SEVERE THUNDERSTORM CONTINUES TO HOLD TOGETHER AND
MOVE NORTH INTO NORTHERN LARAMIE COUNTY. WENT AHEAD AND ADDED
PLATTE AND GOSHEN COUNTIES TO THE TORNADO WATCH AS THIS STORM
COULD PRODUCE SEVERE THUNDERSTORMS THERE. PLUS THE ENVIRONMENT IS
PROBABLY BETTER UP THERE FOR MORE WIDESPREAD THUNDERSTORM
DEVELOPMENT. UPDATES HAVE BEEN SENT.
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT)
ISSUED AT 300 PM MDT SAT AUG 3 2013
FORECAST CHALLENGES DEAL WITH THUNDERSTORM TIMING AND LOCATION OF
SEVERE THUNDERSTORMS THIS AFTERNOON THROUGH EVENING HOURS.
CURRENTLY...BOUNDARY LAYING ALONG THE LARAMIE RANGE EARLY THIS
AFTERNOON...SEPARATING FAIRLY DRY AIR TO THE WEST FROM REALLY
MOIST AIR TO THE EAST. DEWPOINTS IN LARAMIE IN THE MID 30S...HERE
AT CHEYENNE WE ARE SEEING UPPER 50S AND OUT BY SIDNEY...MID 60
DEWPOINTS. STRATUS HAS BEEN SLOW TO BREAK UP LATE THIS
MORNING/EARLY THIS AFTERNOON. STILL GETTING REPORTS OF STRATUS IN
THE PANHANDLE AND AS FAR WEST AS TORRINGTON. CHEYENNE HAS REMAINED
UNDER MOSTLY SUNNY SKIES AND CUMULUS HAS BEGUN TO BUILD OVER THE
SOUTHERN LARAMIE RANGE...EXTENDING SOUTH INTO THE MOUNTAINS OF
COLORADO. GETTING OBSERVED LIGHTNING STRIKES OVER CENTRAL
COLORADO...BUT SO FAR...THE CHEYENNE CWFA HAS REMAINED PRETTY MUCH
ECHO FREE. MONSOONAL MOISTURE CONTINUES TO MOVE INTO SOUTH CENTRAL
WYOMING ON WATER VAPOR IMAGERY...MAINLY OVER SOUTHERN CARBON AND
ALBANY COUNTIES THROUGH THE MORNING HOURS.
DO BELIEVE ITS ONLY A MATTER OF TIME FOR CONVECTION TO INITIATE
THIS AFTERNOON. LATEST SPC MESOANALIST PAGE SHOWING SURFACE BASED CAPE
VALUES INCREASING TO AROUND 3500 J/KG JUST SOUTH OF THE CWFA IN
COLORADO WITH AROUND 2500 TO 3000 J/KG JUST NUDGING INTO THE SOUTH
LARAMIE RANGE. STILL SEEING SOME CONVECTIVE INHIBITION EAST OF
CHEYENNE...SPREADING NORTH AND EAST. SPC MESOANALYST PAGE SHOWING
STILL AROUND 100-150 J/KG CONVECTIVE INHIBITION FOR THESE AREAS.
CURRENTLY THINKING AND THIS IS BACKED UP BY LATEST HRRR FORECASTS
IS THAT CONVECTION WILL INITIATE JUST WEST OF CHEYENNE...THEN
SLOWLY SPREAD EAST AND NORTH AS THE CAP ERODES.
MAIN THREATS WITH THUNDERSTORMS TODAY LOOKS TO BE LARGE HAIL AND
DAMAGING WINDS. BULK SHEAR ON THE ORDER OF 40 TO 45KTS. BUT LATER
THIS AFTERNOON...NAM SOUNDINGS ARE SHOWING HELICITY VALUES
INCREASING ABOVE 200 M2/S2 FOR CHEYENNE AND THE SOUTHERN
PANHANDLE...SO CAN NOT RULE OUT SOME TORNADIC SUPERCELLS LATE THIS
AFTERNOON AND EARLY EVENING. LCLS PRETTY LOW...WITH NAM FORECASTING
ANYWHERE FROM 2K TO 3K AGL. FINALLY...HEAVY RAIN IS A CONCERN WITH
PWATS CLIMBING TO OVER 1 INCH HERE AT CHEYENNE AND 1.4 INCHES OUT
BY SIDNEY. STORM MOTIONS ARE FAIRLY SLOW...GENERALLY OUT OF THE
WEST AT LESS THAN 10KTS...SO WE COULD BE LOOKING AT A FLASH FLOOD
THREAT AS WELL IN AREAS THAT SEE TRAINING STORMS. STORMS SHOULD
CONTINUE INTO THE MID TO LATE EVENING HOURS...SPREADING INTO THE
PANHANDLE BY 6 PM OR SO TONIGHT.
FOR SUNDAY...MODELS INDICATING A REPEAT OF TODAYS WEATHER WITH
POSSIBLY CONVECTION FURTHER EAST INTO THE PANHANDLE INITIALLY.
SEVERE THUNDERSTORMS LOOK MORE OUT OVER THE PANHANDLE SUNDAY VS
INITIATING HERE IN SOUTHEAST WYOMING.
.LONG TERM...(TUESDAY THROUGH SATURDAY)
ISSUED AT 320 PM MDT SAT AUG 3 2013
MAIN FORECAST CONCERN THROUGH NEXT WEEK WILL BE A STRONG MID
SUMMER COLD FRONT PUSHING ACROSS THE GREAT PLAINS AND INTO THE
FORECAST AREA...AS THE DEEP 543DM UPPER LEVEL LOW SETTLES OVER
SOUTHERN CANADA NEAR THE GREAT LAKES REGION. THIS IS PRETTY
UNUSUAL FOR THIS TIME OF THE YEAR...ALTHOUGH THE ROCKY MOUNTAIN
REGION WILL NOT SEE THE MAJORITY OF THIS COOLER AIR. MODELS SHOW
THIS FRONT QUICKLY MOVING ACROSS THE AREA TUESDAY AND TUESDAY
EVENING WITH HIGH TEMPERATURES AROUND 10 TO 15 DEGREES COOLER ON
WEDNESDAY AND THURSDAY. WITH SUBTROPICAL MONSOON MOISTURE IN
PLACE...A DAILY CHANCE OF SHOWERS AND THUNDERSTORMS IS ANTICIPATED
ACROSS MOST OF THE FORECAST AREA. THE BEST CHANCE WILL REMAIN OVER
THE MOUNTAINS AND ALONG/EAST OF THE LARAMIE RANGE...PRIMARILY FROM
MID AFTERNOON THROUGH EARLY IN THE EVENING. SOME OF THESE SHOWERS
MAY CONTINUE INTO THE OVERNIGHT HOURS...ESPECIALLY WEDNESDAY AND
THURSDAY NIGHT.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY MORNING)
ISSUED AT 1144 AM MDT SAT AUG 3 2013
IFR TO LIFR CEILINGS AND VISIBILITIES WILL CONTINUE ACROSS EASTERN
PORTIONS OF THE FORECAST AREA EARLY THIS AFTERNOON AS EAST TO
SOUTHEAST UPSLOPE FLOW COMBINES WITH A VERY MOISTURE BOUNDARY LAYER.
CONDITIONS WILL BE SLOW TO IMPROVE WITH SOME AREAS SUCH AS KSNY
LIKELY NOT FULLY BREAK OUT OF MVFR CONDITIONS TODAY. SHOWERS AND
THUNDERSTORMS WILL REDEVELOP OVER THE MOUNTAINS IN THE NEXT HOUR OR
TWO...AND WILL MOVE EAST ACROSS THE PLAINS THROUGH THE AFTERNOON
AND EVENING. EXPECTING IFR TO MVFR CONDITIONS IN BRIEF HEAVY RAIN
ALONG WITH GUSTY AND ERRATIC DOWNDRAFT WINDS. STORMS THAT OCCUR NEAR
THE WY/NE BORDER AND SITES TO THE EAST ARE CAPABLE OF PRODUCING
LARGE HAIL AS WELL. WITH LOW CIGS AND PATCHY FOG LINGERING OVER
PORTIONS OF WESTERN NEBRASKA...THERE IS A LOT OF UNCERTAINTY AS TO
WHEN TSTORMS WILL MOVE OVER THOSE AREAS DUE TO A STABLE LOW BOUNDARY
LAYER. KEPT VCTS IN THOSE LOCATIONS DUE TO THE LACK OF CONFIDENCE
ABOUT TSTORM TIMING LATE THIS AFTERNOON AND INTO THIS EVENING.
TSTORMS WILL DISSIPATE LATE TONIGHT...BUT WITH MOIST SOUTHERLY FLOW
A RETURN TO IFR/LIFR CONDITIONS TO EASTERN TERMINALS IS EXPECTED
AGAIN TONIGHT IN LOW CLOUDS AND FOG.
&&
.FIRE WEATHER...
ISSUED AT 300 PM MDT SAT AUG 3 2013
LIGHT WINDS AND MONSOONAL MOISTURE SHOULD KEEP FIRE WEATHER ISSUES
AT BAY FOR TODAY AND SUNDAY. AREAS EAST OF THE LARAMIE RANGE
SHOULD SEE CONTINUED GOOD CHANCES AT WETTING RAINS...HIGH
HUMIDITIES AND EASTERLY UPSLOPING WINDS. AREAS WEST WILL SEE DRIER
CONDITIONS WITH AFTERNOON HUMIDITIES FALLING INTO MID TEENS.
FORTUNATELY...WINDS SHOULD STAY LIGHT OUT THAT WAY KEEPING FIRE
WEATHER CONCERNS MINIMAL. BY MONDAY...SURFACE HIGH PRESSURE MOVING
INTO NORTH CENTRAL COLORADO WILL RE-ESTABLISH WESTERLY WINDS WITH
DRIER AIR FILTERING IN TO AREAS EAST OF THE LARAMIE RANGE. WINDS
WILL REMAIN LIGHT THOUGH...WHICH WILL KEEP FIRE WEATHER MINIMIZED.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&
$$
UPDATE...CLAYCOMB
SHORT TERM...CLAYCOMB
LONG TERM...TJT
AVIATION...TJT
FIRE WEATHER...CLAYCOMB
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
320 PM MDT SAT AUG 3 2013
.SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT)
ISSUED AT 300 PM MDT SAT AUG 3 2013
FORECAST CHALLENGES DEAL WITH THUNDERSTORM TIMING AND LOCATION OF
SEVERE THUNDERSTORMS THIS AFTERNOON THROUGH EVENING HOURS.
CURRENTLY...BOUNDARY LAYING ALONG THE LARAMIE RANGE EARLY THIS
AFTERNOON...SEPARATING FAIRLY DRY AIR TO THE WEST FROM REALLY
MOIST AIR TO THE EAST. DEWPOINTS IN LARAMIE IN THE MID 30S...HERE
AT CHEYENNE WE ARE SEEING UPPER 50S AND OUT BY SIDNEY...MID 60
DEWPOINTS. STRATUS HAS BEEN SLOW TO BREAK UP LATE THIS
MORNING/EARLY THIS AFTERNOON. STILL GETTING REPORTS OF STRATUS IN
THE PANHANDLE AND AS FAR WEST AS TORRINGTON. CHEYENNE HAS REMAINED
UNDER MOSTLY SUNNY SKIES AND CUMULUS HAS BEGUN TO BUILD OVER THE
SOUTHERN LARAMIE RANGE...EXTENDING SOUTH INTO THE MOUNTAINS OF
COLORADO. GETTING OBSERVED LIGHTNING STRIKES OVER CENTRAL
COLORADO...BUT SO FAR...THE CHEYENNE CWFA HAS REMAINED PRETTY MUCH
ECHO FREE. MONSOONAL MOISTURE CONTINUES TO MOVE INTO SOUTH CENTRAL
WYOMING ON WATER VAPOR IMAGERY...MAINLY OVER SOUTHERN CARBON AND
ALBANY COUNTIES THROUGH THE MORNING HOURS.
DO BELIEVE ITS ONLY A MATTER OF TIME FOR CONVECTION TO INITIATE
THIS AFTERNOON. LATEST SPC MESOANALIST PAGE SHOWING SURFACE BASED CAPE
VALUES INCREASING TO AROUND 3500 J/KG JUST SOUTH OF THE CWFA IN
COLORADO WITH AROUND 2500 TO 3000 J/KG JUST NUDGING INTO THE SOUTH
LARAMIE RANGE. STILL SEEING SOME CONVECTIVE INHIBITION EAST OF
CHEYENNE...SPREADING NORTH AND EAST. SPC MESOANALYST PAGE SHOWING
STILL AROUND 100-150 J/KG CONVECTIVE INHIBITION FOR THESE AREAS.
CURRENTLY THINKING AND THIS IS BACKED UP BY LATEST HRRR FORECASTS
IS THAT CONVECTION WILL INITIATE JUST WEST OF CHEYENNE...THEN
SLOWLY SPREAD EAST AND NORTH AS THE CAP ERODES.
MAIN THREATS WITH THUNDERSTORMS TODAY LOOKS TO BE LARGE HAIL AND
DAMAGING WINDS. BULK SHEAR ON THE ORDER OF 40 TO 45KTS. BUT LATER
THIS AFTERNOON...NAM SOUNDINGS ARE SHOWING HELICITY VALUES
INCREASING ABOVE 200 M2/S2 FOR CHEYENNE AND THE SOUTHERN
PANHANDLE...SO CAN NOT RULE OUT SOME TORNADIC SUPERCELLS LATE THIS
AFTERNOON AND EARLY EVENING. LCLS PRETTY LOW...WITH NAM FORECASTING
ANYWHERE FROM 2K TO 3K AGL. FINALLY...HEAVY RAIN IS A CONCERN WITH
PWATS CLIMBING TO OVER 1 INCH HERE AT CHEYENNE AND 1.4 INCHES OUT
BY SIDNEY. STORM MOTIONS ARE FAIRLY SLOW...GENERALLY OUT OF THE
WEST AT LESS THAN 10KTS...SO WE COULD BE LOOKING AT A FLASH FLOOD
THREAT AS WELL IN AREAS THAT SEE TRAINING STORMS. STORMS SHOULD
CONTINUE INTO THE MID TO LATE EVENING HOURS...SPREADING INTO THE
PANHANDLE BY 6 PM OR SO TONIGHT.
FOR SUNDAY...MODELS INDICATING A REPEAT OF TODAYS WEATHER WITH
POSSIBLY CONVECTION FURTHER EAST INTO THE PANHANDLE INITIALLY.
SEVERE THUNDERSTORMS LOOK MORE OUT OVER THE PANHANDLE SUNDAY VS
INITIATING HERE IN SOUTHEAST WYOMING.
.LONG TERM...(TUESDAY THROUGH SATURDAY)
ISSUED AT 320 PM MDT SAT AUG 3 2013
MAIN FORECAST CONCERN THROUGH NEXT WEEK WILL BE A STRONG MID
SUMMER COLD FRONT PUSHING ACROSS THE GREAT PLAINS AND INTO THE
FORECAST AREA...AS THE DEEP 543DM UPPER LEVEL LOW SETTLES OVER
SOUTHERN CANADA NEAR THE GREAT LAKES REGION. THIS IS PRETTY
UNUSUAL FOR THIS TIME OF THE YEAR...ALTHOUGH THE ROCKY MOUNTAIN
REGION WILL NOT SEE THE MAJORITY OF THIS COOLER AIR. MODELS SHOW
THIS FRONT QUICKLY MOVING ACROSS THE AREA TUESDAY AND TUESDAY
EVENING WITH HIGH TEMPERATURES AROUND 10 TO 15 DEGREES COOLER ON
WEDNESDAY AND THURSDAY. WITH SUBTROPICAL MONSOON MOISTURE IN
PLACE...A DAILY CHANCE OF SHOWERS AND THUNDERSTORMS IS ANTICIPATED
ACROSS MOST OF THE FORECAST AREA. THE BEST CHANCE WILL REMAIN OVER
THE MOUNTAINS AND ALONG/EAST OF THE LARAMIE RANGE...PRIMARILY FROM
MID AFTERNOON THROUGH EARLY IN THE EVENING. SOME OF THESE SHOWERS
MAY CONTINUE INTO THE OVERNIGHT HOURS...ESPECIALLY WEDNESDAY AND
THURSDAY NIGHT.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY MORNING)
ISSUED AT 1144 AM MDT SAT AUG 3 2013
IFR TO LIFR CEILINGS AND VISIBILITIES WILL CONTINUE ACROSS EASTERN
PORTIONS OF THE FORECAST AREA EARLY THIS AFTERNOON AS EAST TO
SOUTHEAST UPSLOPE FLOW COMBINES WITH A VERY MOISTURE BOUNDARY LAYER.
CONDITIONS WILL BE SLOW TO IMPROVE WITH SOME AREAS SUCH AS KSNY
LIKELY NOT FULLY BREAK OUT OF MVFR CONDITIONS TODAY. SHOWERS AND
THUNDERSTORMS WILL REDEVELOP OVER THE MOUNTAINS IN THE NEXT HOUR OR
TWO...AND WILL MOVE EAST ACROSS THE PLAINS THROUGH THE AFTERNOON
AND EVENING. EXPECTING IFR TO MVFR CONDITIONS IN BRIEF HEAVY RAIN
ALONG WITH GUSTY AND ERRATIC DOWNDRAFT WINDS. STORMS THAT OCCUR NEAR
THE WY/NE BORDER AND SITES TO THE EAST ARE CAPABLE OF PRODUCING
LARGE HAIL AS WELL. WITH LOW CIGS AND PATCHY FOG LINGERING OVER
PORTIONS OF WESTERN NEBRASKA...THERE IS A LOT OF UNCERTAINTY AS TO
WHEN TSTORMS WILL MOVE OVER THOSE AREAS DUE TO A STABLE LOW BOUNDARY
LAYER. KEPT VCTS IN THOSE LOCATIONS DUE TO THE LACK OF CONFIDENCE
ABOUT TSTORM TIMING LATE THIS AFTERNOON AND INTO THIS EVENING.
TSTORMS WILL DISSIPATE LATE TONIGHT...BUT WITH MOIST SOUTHERLY FLOW
A RETURN TO IFR/LIFR CONDITIONS TO EASTERN TERMINALS IS EXPECTED
AGAIN TONIGHT IN LOW CLOUDS AND FOG.
&&
.FIRE WEATHER...
ISSUED AT 300 PM MDT SAT AUG 3 2013
LIGHT WINDS AND MONSOONAL MOISTURE SHOULD KEEP FIRE WEATHER ISSUES
AT BAY FOR TODAY AND SUNDAY. AREAS EAST OF THE LARAMIE RANGE
SHOULD SEE CONTINUED GOOD CHANCES AT WETTING RAINS...HIGH
HUMIDITIES AND EASTERLY UPSLOPING WINDS. AREAS WEST WILL SEE DRIER
CONDITIONS WITH AFTERNOON HUMIDITIES FALLING INTO MID TEENS.
FORTUNATELY...WINDS SHOULD STAY LIGHT OUT THAT WAY KEEPING FIRE
WEATHER CONCERNS MINIMAL. BY MONDAY...SURFACE HIGH PRESSURE MOVING
INTO NORTH CENTRAL COLORADO WILL RE-ESTABLISH WESTERLY WINDS WITH
DRIER AIR FILTERING IN TO AREAS EAST OF THE LARAMIE RANGE. WINDS
WILL REMAIN LIGHT THOUGH...WHICH WILL KEEP FIRE WEATHER MINIMIZED.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&
$$
SHORT TERM...CLAYCOMB
LONG TERM...TJT
AVIATION...TJT
FIRE WEATHER...CLAYCOMB