Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 08/10/12
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
1149 PM EDT THU AUG 09 2012
.Forecast Update...
Issued at 1145 PM EDT Thu Aug 9 2012
Updated the forecast to adjust POPs a bit. The 0Z NAM seems to have
the best handle on convection this evening. Convection over central
IN right around the sfc low should continue to move east over the
next 2-4 hrs and may develop a bit further south into our southern
Indiana counties. However, these storms should struggle to reach
severe levels given the lack of forcing further removed from the
front and main upper level wave as well as lack of instability due
to storms early this evening.
The next area of focus looks to be southern IL as wind shear
profiles increase with the upper shortwave dropping south through IL
and into western KY through the early morning hours. SPC
mesoanalysis indicates good moisture convergence along the sfc front
over southern IL with some isld-sct cells noted over western IL to
southeast MO. DCAPE values are at a relative max over southern IL
and western KY. Would expect new convection to develop over
southern IL over the next 2-4 hours, initially push SSE, and then
pivot more easterly into our area during the pre-dawn hours and as
the shortwave pivots aloft. This will probably be our best chance
for strong to severe convection overnight. Forecast confidence in
this occurring is low to medium given model inconsistencies and
banking on convection developing over southern IL.
&&
.Short Term (Tonight through Friday Night)...
Issued at 331 PM EDT Thu Aug 9 2012
...Active Period of Weather Expected This Afternoon and Tonight...
Fairly active period of weather is shaping up for the Ohio Valley
this afternoon and tonight. In the near term, mid-level shortwave
combined with surface temperatures hitting convective temperatures
has resulted in convection firing across the region. Several areas
of convection are occurring across the area. The first is an
organizing line near the I-75 corridor in our eastern sections.
This is being forced by the aforementioned mid-level wave and by
diurnal heating. This activity will continue to head east and into
WFO JKL`s area over the next hour or so. Further west, a well
defined residual outflow boundary was located along our border with
WFO IND. This boundary extends from northern Dubois county NE to
Jefferson County. Convection is firing along this boundary due to
strong moisture convergence and diurnal heating. This activity
should head east-southeast over the next few hours. Finally
additional convection is firing also over west KY. Based on the
latest runs of the LMK WRF and 4km HRRR runs, this activity should
also head east-southeast and may impact our far southwestern
counties later this afternoon. Based on RUC proximity soundings,
this afternoon`s convective activity is likely to remain in the
pulse variety with damaging winds, torrential rains and intense CG
lightning being the main threats.
Latest deterministic and ensemble model runs seem to be showing some
forecast convergence with the forecast for later this evening and
overnight. First mid-level trough will scoot east this evening
while a secondary and more potent mid-level trough dropping down
into the Ohio Valley late tonight. As this wave drops south,
surface cyclone near KSTL will shift northeast while associated
surface cold drags behind. Strong mid-level height falls will
result in widespread synoptic scale lift across the region late
tonight. This combined with forcing along the front should result
in a secondary line of convection developing to our northwest and
slide southeast overnight. Despite this line moving through during
an instability minimum, the upper level dynamics appear to be strong
enough to support convection despite the meager instability.
Current thinking is that a convective line will generate along the
I-70 corridor and then drop southeast overnight. The line will
likely be strong to possibly severe especially to our northwest.
However, as the line heads southeast, it is possible that line may
weaken a bit as it slides through KY. Convection should be pushing
through southern Indiana in the 04-06Z time frame and then through
KY in the 06-11Z time frame. Have gone ahead and bumped up PoPs for
the overnight period. Lows will remain mild with temperatures
falling into the lower-mid 60s in the northwest and mid-upper 60s
elsewhere.
For Friday, the main forecast change here is that a lot more cloud
cover will be likely during the morning hours. Latest model
time-height model cross sections show plenty of low-level moisture
lingering behind the frontal boundary as it pushes through. Thus,
mostly cloudy skies seem very likely in the morning followed by
progressive clearing during the afternoon and into the evening
hours. Highs tomorrow will be quite cool compared to what we`ve
seen over the last few months. We should see readings in the upper
70s in the east with upper 70s to lower 80s in the central and
west. Lows Friday night will be quite comfortable with lows in the
mid-upper 50s.
.Long Term (Saturday through Thursday)...
Issued at 315 PM EDT Thu Aug 9 2012
...Mostly Sunny, Dry, and Cool Weekend Ahead...
A vertically stacked unseasonably far south and strong closed low
will begin to slowly fill over Lake Huron Saturday. This system will
slowly weaken and slowly lift north towards St. James Bay by late
Sunday. In its wake, it will leave residual troughing across the
western Great Lakes and the upper Midwest.
By early Saturday, the occluded front related to this upper low will
already have moved well east of the Commonwealth. Much drier and
cooler air originating in Canada, will have overspread the state by
dawn Saturday.
Expect mostly clear skies and relatively cool temperatures for the
upcoming weekend. Dewpoints will likely fall into the lower 50s by
Saturday afternoon. Highs will struggle to exceed 80 on Saturday
with highs on Sunday warming just a few degrees into the lower 80s.
Overnight lows early Sunday will quite likely reach into the upper
50s, with perhaps our urban areas remaining near 60.
A broad longwave trough will remain centered roughly over the Great
Lakes during the early portion of next week. This will ensure no
repeat of the excessively hot temperatures of early August anytime
soon. Both the latest GFS and the ECMWF show a disturbance sliding
southeast towards the base of this longwave trough Monday and
Tuesday. This system will approach the Commonwealth by late Monday.
At the surface, this system will likely aid in the formation of a
weak surface trough that may serve as a focus for convection
beginning late Monday, possibly continuing through the bulk of
Tuesday. Will introduce a chance of storms for the later half of
Monday, extending through Tuesday.
Temperatures will warm a bit within the Monday through Thursday time
period. However, even by Wednesday through Friday, temperatures
will not exceed our seasonal mid-August averages with highs
remaining in the upper 80s to around 90
&&
.Aviation (00Z TAF issuance)...
Issued at 709 PM EDT Thu Aug 9 2012
Convection continues across the forecast area this evening. An
east-west outflow boundary is roughly located along I-64 in southern
Indiana and Kentucky. Two areas of convection are located along
this boundary...the western cluster is centered over near KHNB while
the eastern one is located northeast of KLEX. In general,
convection should wind down temporarily over the next few hours as
instability wanes. The terminals should generally see VFR
conditions this evening.
Secondary upper level wave and associated cold front are currently
located to our northwest up north of I-70. Regional radars show an
expanding area of convection across central IL and IN. This
convection is progged to move east-southeast and will affect
primarily the KSDF and KLEX terminals later tonight...most likely
after 10/04Z. Convection reaching the KBWG area is much more
uncertain as many of the 18Z numerical model runs weaken the line of
convection as it heads through KY. For now have gone a little more
optimistic at KBWG and plan on carrying only VCTS for the overnight
period. It still looks like we`ll have plenty of low clouds in the
morning with low end MVFR cigs during the morning hours.
Progressive clearing looks to take place after 10/15Z.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
KY...NONE.
$$
Update...........AMS
Short Term.......MJ
Long Term........JSD
Aviation.........MJ
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
850 PM EDT THU AUG 09 2012
.Forecast Update...
Issued at 845 PM EDT Thu Aug 9 2012
Convection across the area has decreased in intensity for now.
However, steady rains with an occasional t-storm continue over
Dubois County, IN in the Huntingburg area. Although no flooding has
been reported from sources in that area, this could be a location to
watch overnight for flooding issues along with other areas over
southern Indiana and the Bluegrass that had flood
advisories/warnings out earlier this evening.
As for convection tonight, the main upper low was pushing south into
the upper Midwest as of 0Z with a sfc cold front stretching from
west central IN to southeast MO to northern TX. A strengthening sfc
low was noted across west central IN where the strongest convection
has been firing over the last few hours. The sfc low is still
progged to strengthen and move northeast overnight with the cold
front push ESE into our area after midnight. Ongoing convection to
our NW should move into our area after midnight according the local
LMKARW model which is handling convection the best today. However,
strength of that convection is in question due to earlier t-storms
over the area. Convection may become more elevated has it gets into
southern Indiana where a shallow stable layer and less atmospheric
instability exist. However, some portions of central KY that did
not receive convection this evening are still unstable with
effective 30-40 kt shear and good moisture convergence noted over
western KY. Another factor to consider in the equation is the
strength of the overall synoptic system which is impressive for this
time of year and we will be seeing better bulk shear values move
into our area later tonight as the sfc front and trough move through
the region. Therefore cannot rule out strong to severe storms for
late tonight, however, conditions look less favorable in areas that
saw storms this evening. Will continue to monitor upstream trends
this evening and adjust the forecast as necessary. Prime time for
storms tonight would be after midnight through about 8 am EDT across
our area.
&&
.Short Term (Tonight through Friday Night)...
Issued at 331 PM EDT Thu Aug 9 2012
...Active Period of Weather Expected This Afternoon and Tonight...
Fairly active period of weather is shaping up for the Ohio Valley
this afternoon and tonight. In the near term, mid-level shortwave
combined with surface temperatures hitting convective temperatures
has resulted in convection firing across the region. Several areas
of convection are occurring across the area. The first is an
organizing line near the I-75 corridor in our eastern sections.
This is being forced by the aforementioned mid-level wave and by
diurnal heating. This activity will continue to head east and into
WFO JKL`s area over the next hour or so. Further west, a well
defined residual outflow boundary was located along our border with
WFO IND. This boundary extends from northern Dubois county NE to
Jefferson County. Convection is firing along this boundary due to
strong moisture convergence and diurnal heating. This activity
should head east-southeast over the next few hours. Finally
additional convection is firing also over west KY. Based on the
latest runs of the LMK WRF and 4km HRRR runs, this activity should
also head east-southeast and may impact our far southwestern
counties later this afternoon. Based on RUC proximity soundings,
this afternoon`s convective activity is likely to remain in the
pulse variety with damaging winds, torrential rains and intense CG
lightning being the main threats.
Latest deterministic and ensemble model runs seem to be showing some
forecast convergence with the forecast for later this evening and
overnight. First mid-level trough will scoot east this evening
while a secondary and more potent mid-level trough dropping down
into the Ohio Valley late tonight. As this wave drops south,
surface cyclone near KSTL will shift northeast while associated
surface cold drags behind. Strong mid-level height falls will
result in widespread synoptic scale lift across the region late
tonight. This combined with forcing along the front should result
in a secondary line of convection developing to our northwest and
slide southeast overnight. Despite this line moving through during
an instability minimum, the upper level dynamics appear to be strong
enough to support convection despite the meager instability.
Current thinking is that a convective line will generate along the
I-70 corridor and then drop southeast overnight. The line will
likely be strong to possibly severe especially to our northwest.
However, as the line heads southeast, it is possible that line may
weaken a bit as it slides through KY. Convection should be pushing
through southern Indiana in the 04-06Z time frame and then through
KY in the 06-11Z time frame. Have gone ahead and bumped up PoPs for
the overnight period. Lows will remain mild with temperatures
falling into the lower-mid 60s in the northwest and mid-upper 60s
elsewhere.
For Friday, the main forecast change here is that a lot more cloud
cover will be likely during the morning hours. Latest model
time-height model cross sections show plenty of low-level moisture
lingering behind the frontal boundary as it pushes through. Thus,
mostly cloudy skies seem very likely in the morning followed by
progressive clearing during the afternoon and into the evening
hours. Highs tomorrow will be quite cool compared to what we`ve
seen over the last few months. We should see readings in the upper
70s in the east with upper 70s to lower 80s in the central and
west. Lows Friday night will be quite comfortable with lows in the
mid-upper 50s.
.Long Term (Saturday through Thursday)...
Issued at 315 PM EDT Thu Aug 9 2012
...Mostly Sunny, Dry, and Cool Weekend Ahead...
A vertically stacked unseasonably far south and strong closed low
will begin to slowly fill over Lake Huron Saturday. This system will
slowly weaken and slowly lift north towards St. James Bay by late
Sunday. In its wake, it will leave residual troughing across the
western Great Lakes and the upper Midwest.
By early Saturday, the occluded front related to this upper low will
already have moved well east of the Commonwealth. Much drier and
cooler air originating in Canada, will have overspread the state by
dawn Saturday.
Expect mostly clear skies and relatively cool temperatures for the
upcoming weekend. Dewpoints will likely fall into the lower 50s by
Saturday afternoon. Highs will struggle to exceed 80 on Saturday
with highs on Sunday warming just a few degrees into the lower 80s.
Overnight lows early Sunday will quite likely reach into the upper
50s, with perhaps our urban areas remaining near 60.
A broad longwave trough will remain centered roughly over the Great
Lakes during the early portion of next week. This will ensure no
repeat of the excessively hot temperatures of early August anytime
soon. Both the latest GFS and the ECMWF show a disturbance sliding
southeast towards the base of this longwave trough Monday and
Tuesday. This system will approach the Commonwealth by late Monday.
At the surface, this system will likely aid in the formation of a
weak surface trough that may serve as a focus for convection
beginning late Monday, possibly continuing through the bulk of
Tuesday. Will introduce a chance of storms for the later half of
Monday, extending through Tuesday.
Temperatures will warm a bit within the Monday through Thursday time
period. However, even by Wednesday through Friday, temperatures
will not exceed our seasonal mid-August averages with highs
remaining in the upper 80s to around 90
&&
.Aviation (00Z TAF issuance)...
Issued at 709 PM EDT Thu Aug 9 2012
Convection continues across the forecast area this evening. An
east-west outflow boundary is roughly located along I-64 in southern
Indiana and Kentucky. Two areas of convection are located along
this boundary...the western cluster is centered over near KHNB while
the eastern one is located northeast of KLEX. In general,
convection should wind down temporarily over the next few hours as
instability wanes. The terminals should generally see VFR
conditions this evening.
Secondary upper level wave and associated cold front are currently
located to our northwest up north of I-70. Regional radars show an
expanding area of convection across central IL and IN. This
convection is progged to move east-southeast and will affect
primarily the KSDF and KLEX terminals later tonight...most likely
after 10/04Z. Convection reaching the KBWG area is much more
uncertain as many of the 18Z numerical model runs weaken the line of
convection as it heads through KY. For now have gone a little more
optimistic at KBWG and plan on carrying only VCTS for the overnight
period. It still looks like we`ll have plenty of low clouds in the
morning with low end MVFR cigs during the morning hours.
Progressive clearing looks to take place after 10/15Z.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
KY...NONE.
$$
Update...........AMS
Short Term.......MJ
Long Term........JSD
Aviation.........MJ
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
709 PM EDT THU AUG 09 2012
...Updated Aviation Discussion...
.Short Term (Tonight through Friday Night)...
Issued at 331 PM EDT Thu Aug 9 2012
...Active Period of Weather Expected This Afternoon and Tonight...
Fairly active period of weather is shaping up for the Ohio Valley
this afternoon and tonight. In the near term, mid-level shortwave
combined with surface temperatures hitting convective temperatures
has resulted in convection firing across the region. Several areas
of convection are occurring across the area. The first is an
organizing line near the I-75 corridor in our eastern sections.
This is being forced by the aforementioned mid-level wave and by
diurnal heating. This activity will continue to head east and into
WFO JKL`s area over the next hour or so. Further west, a well
defined residual outflow boundary was located along our border with
WFO IND. This boundary extends from northern Dubois county NE to
Jefferson County. Convection is firing along this boundary due to
strong moisture convergence and diurnal heating. This activity
should head east-southeast over the next few hours. Finally
additional convection is firing also over west KY. Based on the
latest runs of the LMK WRF and 4km HRRR runs, this activity should
also head east-southeast and may impact our far southwestern
counties later this afternoon. Based on RUC proximity soundings,
this afternoon`s convective activity is likely to remain in the
pulse variety with damaging winds, torrential rains and intense CG
lightning being the main threats.
Latest deterministic and ensemble model runs seem to be showing some
forecast convergence with the forecast for later this evening and
overnight. First mid-level trough will scoot east this evening
while a secondary and more potent mid-level trough dropping down
into the Ohio Valley late tonight. As this wave drops south,
surface cyclone near KSTL will shift northeast while associated
surface cold drags behind. Strong mid-level height falls will
result in widespread synoptic scale lift across the region late
tonight. This combined with forcing along the front should result
in a secondary line of convection developing to our northwest and
slide southeast overnight. Despite this line moving through during
an instability minimum, the upper level dynamics appear to be strong
enough to support convection despite the meager instability.
Current thinking is that a convective line will generate along the
I-70 corridor and then drop southeast overnight. The line will
likely be strong to possibly severe especially to our northwest.
However, as the line heads southeast, it is possible that line may
weaken a bit as it slides through KY. Convection should be pushing
through southern Indiana in the 04-06Z time frame and then through
KY in the 06-11Z time frame. Have gone ahead and bumped up PoPs for
the overnight period. Lows will remain mild with temperatures
falling into the lower-mid 60s in the northwest and mid-upper 60s
elsewhere.
For Friday, the main forecast change here is that a lot more cloud
cover will be likely during the morning hours. Latest model
time-height model cross sections show plenty of low-level moisture
lingering behind the frontal boundary as it pushes through. Thus,
mostly cloudy skies seem very likely in the morning followed by
progressive clearing during the afternoon and into the evening
hours. Highs tomorrow will be quite cool compared to what we`ve
seen over the last few months. We should see readings in the upper
70s in the east with upper 70s to lower 80s in the central and
west. Lows Friday night will be quite comfortable with lows in the
mid-upper 50s.
.Long Term (Saturday through Thursday)...
Issued at 315 AM EDT Thu Aug 9 2012
...Mostly Sunny, Dry, and Cool Weekend Ahead...
A vertically stacked unseasonably far south and strong closed low
will begin to slowly fill over Lake Huron Saturday. This system will
slowly weaken and slowly lift north towards St. James Bay by late
Sunday. In its wake, it will leave residual troughing across the
western Great Lakes and the upper Midwest.
By early Saturday, the occluded front related to this upper low will
already have moved well east of the Commonwealth. Much drier and
cooler air originating in Canada, will have overspread the state by
dawn Saturday.
Expect mostly clear skies and relatively cool temperatures for the
upcoming weekend. Dewpoints will likely fall into the lower 50s by
Saturday afternoon. Highs will struggle to exceed 80 on Saturday
with highs on Sunday warming just a few degrees into the lower 80s.
Overnight lows early Sunday will quite likely reach into the upper
50s, with perhaps our urban areas remaining near 60.
A broad longwave trough will remain centered roughly over the Great
Lakes during the early portion of next week. This will ensure no
repeat of the excessively hot temperatures of early August anytime
soon. Both the latest GFS and the ECMWF show a disturbance sliding
southeast towards the base of this longwave trough Monday and
Tuesday. This system will approach the Commonwealth by late Monday.
At the surface, this system will likely aid in the formation of a
weak surface trough that may serve as a focus for convection
beginning late Monday, possibly continuing through the bulk of
Tuesday. Will introduce a chance of storms for the later half of
Monday, extending through Tuesday.
Temperatures will warm a bit within the Monday through Thursday time
period. However, even by Wednesday through Friday, temperatures
will not exceed our seasonal mid-August averages with highs
remaining in the upper 80s to around 90
&&
.Aviation (00Z TAF issuance)...
Issued at 709 PM EDT Thu Aug 9 2012
Convection continues across the forecast area this evening. An
east-west outflow boundary is roughly located along I-64 in southern
Indiana and Kentucky. Two areas of convection are located along
this boundary...the western cluster is centered over near KHNB while
the eastern one is located northeast of KLEX. In general,
convection should wind down temporarily over the next few hours as
instability wanes. The terminals should generally see VFR
conditions this evening.
Secondary upper level wave and associated cold front are currently
located to our northwest up north of I-70. Regional radars show an
expanding area of convection across central IL and IN. This
convection is progged to move east-southeast and will affect
primarily the KSDF and KLEX terminals later tonight...most likely
after 10/04Z. Convection reaching the KBWG area is much more
uncertain as many of the 18Z numerical model runs weaken the line of
convection as it heads through KY. For now have gone a little more
optimistic at KBWG and plan on carrying only VCTS for the overnight
period. It still looks like we`ll have plenty of low clouds in the
morning with low end MVFR cigs during the morning hours.
Progressive clearing looks to take place after 10/15Z.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
KY...NONE.
$$
Short Term.......MJ
Long Term........JSD
Aviation.........MJ
AREA FORECAST DISCUSSION
NWS CARIBOU ME
102 AM EDT WED AUG 8 2012
.SYNOPSIS...
HIGH PRESSURE WILL MOVE EAST OF THE AREA TONIGHT. A WEAK FRONTAL
BOUNDARY WILL APPROACH FROM THE NORTHWEST ON WEDNESDAY AND STALL
OVER THE AREA THROUGH LATE WEEK.
&&
.NEAR TERM /THROUGH TODAY/...
1 AM UPDATE...ADJUSTED SKY GRID TO ACCOUNT FOR LATEST SATELLITE
TREND.
10 PM UPDATE...TWEAKED TEMPERATURES TO MATCH THE LATEST TRENDS.
RADAR SHOWING SOME SHOWERS MOVE NE ACROSS QUEBEC. RUC HAS SOME OF
THESE SHOWERS SKIRTING NORTHERN AND NWRN AREAS OVERNIGHT INTO
EARLY MORNING. LATEST FCST HAS THIS HANDLED WELL.
PREVIOUS DISCUSSION...
TONIGHT WILL REMAIN MOSTLY CLEAR IN SOUTHERN AND SOUTHEAST AREAS.
SOME CLOUDS WILL GRADUALLY INCREASE ACROSS THE NORTHWEST AS A WEAK
COLD FRONT SLOWLY APPROACHES FROM QUEBEC. SOME SHOWERS MAY AFFECT
FAR NORTHWESTERN AREAS LATE TONIGHT OR WEDNESDAY MORNING. AS THE
FRONT NEARS WEDNESDAY AFTERNOON SOME THUNDERSTORMS WILL BE
POSSIBLE. THE BEST CHANCES FOR THUNDERSTORMS WEDNESDAY AFTERNOON
WILL BE OVER FAR NORTHWESTERN AREAS NEAR THE FRONTAL BOUNDARY
WHERE SOME CONVERGENCE WILL OFFER SUPPORT FOR THUNDERSTORM
ACTIVITY. BOTH THE NAM AND GFS ARE FORECASTING CAPES NEAR 300
J/KG. CAPES AROUND 300 CAN SUPPORT SOME CONVECTION BUT ARE LIKELY
TOO WEAK TO SUPPORT ANYTHING SEVERE. TEMPS TONIGHT WILL RANGE FROM
THE MID 50S EAST WHERE SKIES WILL BE MOSTLY CLEAR TO NEAR 60
NORTHWEST WHERE SOME CLOUD COVER WILL LIMIT COOLING. TEMPS ON
WEDNESDAY WILL BE IN THE LOW 80S IN MOST AREAS.
&&
.SHORT TERM /TONIGHT THROUGH 6 PM THURSDAY/...
A WEAK AREA OF LOW PRESSURE AND AN ASSOCIATED COLD FRONT WILL
MOVE ACROSS THE REGION WEDNESDAY NIGHT BRINGING SOME SHOWERS AND
THUNDERSTORMS MAINLY TO THE NORTHERN HALF OF THE REGION. AS
ABUNDANT LOW LEVEL MOISTURE IS DRAWN NORTH ON SOUTHERLY WINDS
AHEAD OF THE FRONT THIS WILL RESULT IN FOG DEVELOPMENT OVER
DOWNEAST AREAS. THE FRONT STALLS ACROSS THE REGION ON THURSDAY
RESULTING IN CONSIDERABLE CLOUDINESS WITH ADDITIONAL SHOWERS AND
THUNDERSTORMS. THE NAM DEPICTS CAPE VALUES EXCEEDING 1000 J/KG BY
THE AFTERNOON WITH 0-6 KM SHEAR VALUES EXCEEDING 40 KNOTS. HOWEVER
CLOUD COVER WILL ACT TO LIMIT THE POTENTIAL FOR SEVERE STORMS AS
IT LIMITS HEATING. HAVE GONE WITH UPPER 70S NORTH AND LOW 80S
SOUTH. ANY CONVECTION WILL WIND DOWN THURSDAY EVENING. HAVE
MAINTAINED SHOWERS THROUGH THE NIGHT WITH THE FRONT STALLING DOWN
EAST. LOWS WILL BE IN THE LOW TO MID 60S IN THE RATHER HUMID AIR
MASS.
MODELS BEGIN TO DIVERGE HEADING INTO FRIDAY. LOW PRESSURE LOOKS
TO DEVELOP FRIDAY IN THE OHIO VALLEY WITH A SHIELD OF RAIN
EXTENDING NORTH AND EAST FROM THIS SYSTEM ALONG THE FRONT. THE NAM
AND THE ECMWF ARE FAIRLY AGGRESSIVE BRINGING STEADIER AND HEAVIER
PRECIPITATION INTO THE REGION DURING THE DAY COMPARED TO THE GFS
AND ESPECIALLY THE GEM GLOBAL. AT THIS POINT OPTED TO KEEP IN
CHANCE POPS OVER MOST OF THE CWA WITH A SMALL AREA OF LIKELY POPS
NUDGING INTO AREAS JUST WEST OF BANGOR BY LATE DAY.
&&
.LONG TERM /THURSDAY NIGHT THROUGH WEDNESDAY/...
LOW PRESSURE WILL INTENSIFY ACROSS THE MID ATLANTIC REGION FRIDAY
NIGHT WITH HIGH PRESSURE LOCATED NORTH OF THE REGION. THE LOW
THEN SLOWLY LIFTS NORTH SATURDAY...WHILE HIGH PRESSURE MOVES
NORTHEAST. UNCERTAINTY STILL EXISTS REGARDING HOW QUICKLY RAIN IS
ABLE TO EXPAND ACROSS THE FORECAST AREA FRIDAY NIGHT THROUGH
SATURDAY. HIGH PRESSURE TO THE NORTHEAST SHOULD HELP SUPPLY LOW
LEVEL DRY AIR WHICH COULD SLOW THE EXPANSION OF RAIN ACROSS THE
REGION. EXPECT THE BEST CHANCES OF RAIN WILL REMAIN ACROSS
SOUTHWEST PORTIONS OF THE FORECAST AREA FRIDAY NIGHT THROUGH EARLY
SATURDAY. THE RAIN SHOULD THEN EXPAND ACROSS THE REGION THROUGH
THE REMAINDER OF SATURDAY. THE LOW WILL LIFT NORTH SATURDAY NIGHT
THROUGH SUNDAY...DRAWING AN OCCLUDED FRONT ACROSS THE FORECAST
AREA. RAIN IS EXPECTED ACROSS THE ENTIRE REGION SATURDAY NIGHT
THROUGH EARLY SUNDAY IN ADVANCE OF THE OCCLUSION...WITH
PRECIPITATION THEN TAPERING TO SHOWERS IN THE WAKE OF THE
OCCLUSION LATER SUNDAY. THE LOW WILL LIFT NORTH OF THE REGION
MONDAY...WITH A SLIGHT CHANCE OF SHOWERS LINGERING ACROSS NORTHERN
AREAS. A COLD FRONT WILL APPROACH LATER TUESDAY BRINGING A CHANCE
OF SHOWERS AND THUNDERSTORMS TO MOSTLY NORTHERN AREAS DURING THE
AFTERNOON. TEMPERATURES SHOULD BE AT SLIGHTLY BELOW NORMAL LEVELS
SATURDAY/SUNDAY...WITH NEAR NORMAL LEVEL TEMPERATURES EXPECTED
MONDAY/TUESDAY.
&&
.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
NEAR TERM: SOME PATCHY FOG MAY AFFECT DOWNEAST AREAS LATE TONIGHT.
OTHERWISE...VFR CONDITIONS ARE EXPECTED ACROSS THE AREA THROUGH
WEDNESDAY.
SHORT TERM: IFR LIKELY TO DEVELOP WEDNESDAY NIGHT SOUTH OF HUL AND MLT
WITH STRATUS AND FOG. THIS WILL CONTINUE INTO EARLY THURSDAY MORNING.
VFR FOR LATER THURSDAY MORNING INTO THE EVENING OUTSIDE OF
THUNDERSTORMS. FOG AND STRATUS REAPPEARS THURSDAY NIGHT FOR ALL
TERMINALS AND MAY BE VERY SLOW TO LIFT FRIDAY MORNING...ESPECIALLY
DOWNEAST. LOW PRESSURE ARRIVES BY LATE DAY TO PROVIDE PREDOMINANT
IFR FOR ALL SITES DUE TO LOW CLOUDS AND RAIN. CONDITIONS FRIDAY
NIGHT THROUGH SATURDAY WILL BE DEPENDENT ON HOW QUICKLY RAIN IS
ABLE TO EXPAND ACROSS THE REGION. HOWEVER...MVFR/IFR CONDITIONS
ARE POSSIBLE FRIDAY NIGHT INTO SATURDAY WITH A MORE RAPID
EXPANSION OF THE RAIN. MVFR/IFR CONDITIONS ARE THEN EXPECTED
SATURDAY NIGHT INTO SUNDAY.
&&
.MARINE...
NEAR TERM: WINDS AND SEAS ARE EXPECTED TO REMAIN BELOW SCA TONIGHT
AND WEDNESDAY.
SHORT TERM: FOG IS EXPECTED WEDNESDAY NIGHT AND WILL REMAIN A
FACTOR IN THE FORECAST THROUGH FRIDAY. CONDITIONS ARE EXPECTED TO
BE BELOW SMALL CRAFT ADVISORY LEVELS WEDNESDAY NIGHT THROUGH
FRIDAY.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...HEWITT/RUNYAN
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
250 PM EDT WED AUG 8 2012
.SYNOPSIS...
INCREASING HUMIDITY, PLUS A CANADIAN COLD FRONT MOVING
SOUTHWARD TOWARD LAKE ERIE, MAY SPARK SCATTERED THUNDERSTORMS THIS
AFTERNOON AND EVENING AND AGAIN LATE THURSDAY ACROSS THE UPPER
OHIO VALLEY. LOW PRESSURE, COMING EAST FROM MINNESOTA, WILL JOIN
THE COLD FRONT AND BRING MORE NUMEROUS SHOWERS AND THUNDERSTORMS
FRIDAY.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
RECENT RADAR DATA NOW SHOWS A BAND OF SCATTERED THUNDERSTORMS
DEVELOPING ALONG THE LAKE ERIE BREEZE FRONT. WITH SURFACE DEW
POINTS HAVING INCREASED INTO THE 60 TO 65 RANGE ACROSS NORTHERN
OHIO AND THE PENNSYLVANIA I-80 CORRIDOR, EXPECT THESE STORMS TO
EXPAND IN COVERAGE AND MOVE SOUTHEASTWARD INTO EAST CENTRAL OHIO
AND WEST CENTRAL PENNSYLVANIA BEFORE 6 PM, A SCENARIO PREDICTED BY
RECENT HRRR MODEL OUTPUT.
STORM INTENSITY WILL NEED MONITORED AS SPC CONTINUES TO PROJECT SOME
SEVERE POTENTIAL. SREF MODEL OUTPUT SUPPORTS THIS IDEA AS IT SHOWS
INSTABILITY CAN PEAK ABOVE 1500 J/KG AND VERTICAL WIND SHEAR MAY
REACH 30 KTS.
FORECASTED HIGH TEMPERATURES IN THE 85 TO 90 RANGE, BUT SUCH HIGHS COULD
BE REDUCED IF THUNDERSTORMS PASS THROUGH AN AREA PRIOR TO 5 PM.
AFTER DARK, NOCTURNAL COOLING WILL DISSIPATE CONVECTIVE
INSTABILITY. PATCHY RIVER VALLEY FOG CAN AGAIN DEVELOP AS IT HAS
ON PREVIOUS NIGHTS, AN IDEA SUPPORTED BY RECENT GFS LAMP OUTPUT.
FORECASTED LOW TEMPERATURES USING A BLEND OF RECENT NAM AND GFS
MOS.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH SATURDAY/...
RECENT SREF MODEL OUTPUT, WITH DETAILS FROM THE NAM, SHOW THE
COLD FRONT WILL BECOME STALLED, IN A WEST TO EAST ORIENTATION,
ACROSS THE UPPER OHIO VALLEY THURSDAY. EXPECT BANDS OF SCATTERED
THUNDERSTORMS TO DEVELOP DAYTIME THURSDAY, DUE TO LOW LEVEL
CONVERGENCE IN ADVANCE OF A LOW PRESSURE CENTER COMING EAST FROM
MINNESOTA AND IOWA.
SPC HAS MAINTAINED A SLIGHT RISK OF SEVERE THUNDERSTORMS THURSDAY
AFTERNOON INTO EARLY FRIDAY, WHICH IS SUPPORTED BY SREF MODEL
OUTPUT PROJECTIONS OF INSTABILITY, CAPE 2000+ J/KG, AND VERTICAL
WIND SHEAR, EFFECTIVE BULK SHEAR 25 KTS.
EXPECT SHOWERS AND THUNDERSTORMS TO BE LIKELY FRIDAY DAYTIME AND
EARLY EVENING WITH THE NORTHEAST PASSAGE OF THE DEEPENING LOW
PRESSURE CENTER. CONCUR WITH HPC THAT WIDESPREAD RAIN AMOUNTS CAN
EXCEED 0.50 INCHES, IF NOT 1 INCH.
AS THE LOW PRESSURE CENTER MOVES NORTHWARD PAST LAKE ERIE LATE
FRIDAY NIGHT AND DAYTIME SATURDAY, EXPECT WRAP-AROUND SHOWERS TO
DECREASE IN COVERAGE.
DUE TO THE PROSPECTS FOR SHOWERS AND ACCOMPANYING CLOUDINESS,
CONCURRED WITH GFS AND NAM MOS IN FORECASTING HIGHS THURSDAY NOT AS
WARM AS WEDNESDAY AND THEN COOLER THAN NORMAL FRIDAY. CLOUDS AT
NIGHT AND HUMID CONDITIONS WILL KEEP LOWS WARMER THAN NORMAL
THURSDAY NIGHT. LOWS FRIDAY NIGHT AND HIGHS SATURDAY CAN BE SLIGHTLY
COOLER THAN NORMAL DUE TO COOLER AIR ALOFT.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
WRAPAROUND PRECIPITATION SHOULD BE SHIFTING TO THE NORTHEAST BY
SATURDAY NIGHT...AND HAVE REMOVED PRECIPITATION AFTER MIDNIGHT. 00Z
GFS SEEMS TO BE AN OUTLIER IN SHOWING DIURNAL PRECIPITATION FOR NEXT
WEEK. OTHER MODEL CONSENSUS KEEPS HIGH PRESSURE THROUGH THE
PERIOD...AND HAVE STUCK WITH THIS DRY DEPICTION. SUNDAY AND MONDAY
SHOULD CONTINUE THE TREND OF SLIGHTLY BELOW NORMAL
TEMPERATURES, WITH A SLIGHT RISE IN HIGHS ON TUESDAY AND
WEDNESDAY.
&&
.AVIATION /19Z WEDNESDAY THROUGH MONDAY/...
WEAK FRONT WILL APPROACH THE REGION AND BECOME STATIONARY OVERNIGHT.
THE FRONT OR A LAKE BREEZE BOUNDARY OFF LAKE ERIE COULD SPAWN SOME
SCATTERED SHOWERS/THUNDERSTORMS DURING THE AFTERNOON AND EARLY
EVENING HOURS. CONFIDENCE IS STILL NOT HIGH ENOUGH IN ANY SINGLE
LOCATION TO BE SPECIFIC ABOUT TAF MENTION.
OVERNIGHT...ALL GUIDANCE SUGGESTS A DROP TO AT LEAST MVFR
VISIBILITY...IF NOT LOWER. ALTHOUGH WINDS SHOULD DROP TO 2-3 KTS
OVERNIGHT...THINK THAT THE POSSIBILITY FOR FOG WILL BE DEPENDENT ON
WHERE SHOWERS OCCUR DURING THE AFTERNOON. FOR NOW...WILL ADD MVFR
VISIBILITIES AND ALLOW LATER TAF ISSUANCES TO DECIDE IF IFR
VISIBILITIES ARE REQUIRED IN FORECAST.
MID LEVEL CLOUDS WILL MOVE IN ON THURSDAY...WITH SCATTERED
SHOWERS/STORMS EXPECTED BY THE AFTERNOON AGAIN.
.OUTLOOK...THURSDAY NIGHT THROUGH MONDAY...
RESTRICTIONS CAN BE EXPECTED IN WIDESPREAD SHOWERS AND
THUNDERSTORMS FRIDAY AND FRIDAY NIGHT...WITH MORE ISOLATED
COVERAGE EXPECTED SATURDAY AND SATURDAY NIGHT. SUNDAY SHOULD SEE A
RETURN TO VFR CONDITIONS.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
246 PM EDT WED AUG 8 2012
.SYNOPSIS...
INCREASING HUMIDITY, PLUS A CANADIAN COLD FRONT MOVING
SOUTHWARD TOWARD LAKE ERIE, MAY SPARK SCATTERED THUNDERSTORMS THIS
AFTERNOON AND EVENING AND AGAIN LATE THURSDAY ACROSS THE UPPER
OHIO VALLEY. LOW PRESSURE, COMING EAST FROM MINNESOTA, WILL JOIN
THE COLD FRONT AND BRING MORE NUMEROUS SHOWERS AND THUNDERSTORMS
FRIDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
RECENT RADAR DATA NOW SHOWS A BAND OF SCATTERED THUNDERSTORMS
DEVELOPING ALONG THE LAKE ERIE BREEZE FRONT. WITH SURFACE DEW
POINTS HAVING INCREASED INTO THE 60 TO 65 RANGE ACROSS NORTHERN
OHIO AND THE PENNSYLVANIA I-80 CORRIDOR, EXPECT THESE STORMS TO
EXPAND IN COVERAGE AND MOVE SOUTHEASTWARD INTO EAST CENTRAL OHIO
AND WEST CENTRAL PENNSYLVANIA BEFORE 6 PM, A SCENARIO PREDICTED BY
RECENT HRRR MODEL OUTPUT.
STORM INTENSITY WILL NEED MONITORED AS SPC CONTINUES TO PROJECT SOME
SEVERE POTENTIAL. SREF MODEL OUTPUT SUPPORTS THIS IDEA AS IT SHOWS
INSTABILITY CAN PEAK ABOVE 1500 J/KG AND VERTICAL WIND SHEAR MAY
REACH 30 KTS.
FORECASTED HIGH TEMPERATURES IN THE 85 TO 90 RANGE, BUT SUCH HIGHS COULD
BE REDUCED IF THUNDERSTORMS PASS THROUGH AN AREA PRIOR TO 5 PM.
AFTER DARK, NOCTURNAL COOLING WILL DISSIPATE CONVECTIVE
INSTABILITY. PATCHY RIVER VALLEY FOG CAN AGAIN DEVELOP AS IT HAS
ON PREVIOUS NIGHTS, AN IDEA SUPPORTED BY RECENT GFS LAMP OUTPUT.
FORECASTED LOW TEMPERATURES USING A BLEND OF RECENT NAM AND GFS
MOS.
&&
.SHORT TERM /THURSDAY THROUGH SATURDAY/...
RECENT SREF MODEL OUTPUT, WITH DETAILS FROM THE NAM, SHOW THE
COLD FRONT WILL BECOME STALLED, IN A WEST TO EAST ORIENTATION,
ACROSS THE UPPER OHIO VALLEY THURSDAY. EXPECT BANDS OF SCATTERED
THUNDERSTORMS TO DEVELOP DAYTIME THURSDAY, DUE TO LOW LEVEL
CONVERGENCE IN ADVANCE OF A LOW PRESSURE CENTER COMING EAST FROM
MINNESOTA AND IOWA.
SPC HAS MAINTAINED A SLIGHT RISK OF SEVERE THUNDERSTORMS THURSDAY
AFTERNOON INTO EARLY FRIDAY, WHICH IS SUPPORTED BY SREF MODEL
OUTPUT PROJECTIONS OF INSTABILITY, CAPE 2000+ J/KG, AND VERTICAL
WIND SHEAR, EFFECTIVE BULK SHEAR 25 KTS.
EXPECT SHOWERS AND THUNDERSTORMS TO BE LIKELY FRIDAY DAYTIME AND
EARLY EVENING WITH THE NORTHEAST PASSAGE OF THE DEEPENING LOW
PRESSURE CENTER. CONCUR WITH HPC THAT WIDESPREAD RAIN AMOUNTS CAN
EXCEED 0.50 INCHES, IF NOT 1 INCH.
AS THE LOW PRESSURE CENTER MOVES NORTHWARD PAST LAKE ERIE LATE
FRIDAY NIGHT AND DAYTIME SATURDAY, EXPECT WRAP-AROUND SHOWERS TO
DECREASE IN COVERAGE.
DUE TO THE PROSPECTS FOR SHOWERS AND ACCOMPANYING CLOUDINESS,
CONCURRED WITH GFS AND NAM MOS IN FORECASTING HIGHS THURSDAY NOT AS
WARM AS WEDNESDAY AND THEN COOLER THAN NORMAL FRIDAY. CLOUDS AT
NIGHT AND HUMID CONDITIONS WILL KEEP LOWS WARMER THAN NORMAL
THURSDAY NIGHT. LOWS FRIDAY NIGHT AND HIGHS SATURDAY CAN BE SLIGHTLY
COOLER THAN NORMAL DUE TO COOLER AIR ALOFT.
&&
.LONG TERM /SATURDAY NIGHT THROUGH TUESDAY/...
WRAPAROUND PRECIPITATION SHOULD BE SHIFTING TO THE NORTHEAST BY
SATURDAY NIGHT...AND HAVE REMOVED PRECIPITATION AFTER MIDNIGHT. 00Z
GFS SEEMS TO BE AN OUTLIER IN SHOWING DIURNAL PRECIPITATION FOR NEXT
WEEK. OTHER MODEL CONSENSUS KEEPS HIGH PRESSURE THROUGH THE
PERIOD...AND HAVE STUCK WITH THIS DRY DEPICTION. SUNDAY AND MONDAY
SHOULD CONTINUE THE TREND OF SLIGHTLY BELOW NORMAL
TEMPERATURES, WITH A SLIGHT RISE IN HIGHS ON TUESDAY.
&&
.AVIATION /19Z WEDNESDAY THROUGH MONDAY/...
WEAK FRONT WILL APPROACH THE REGION AND BECOME STATIONARY OVERNIGHT.
THE FRONT OR A LAKE BREEZE BOUNDARY OFF LAKE ERIE COULD SPAWN SOME
SCATTERED SHOWERS/THUNDERSTORMS DURING THE AFTERNOON AND EARLY
EVENING HOURS. CONFIDENCE IS STILL NOT HIGH ENOUGH IN ANY SINGLE
LOCATION TO BE SPECIFIC ABOUT TAF MENTION.
OVERNIGHT...ALL GUIDANCE SUGGESTS A DROP TO AT LEAST MVFR
VISIBILITY...IF NOT LOWER. ALTHOUGH WINDS SHOULD DROP TO 2-3 KTS
OVERNIGHT...THINK THAT THE POSSIBILITY FOR FOG WILL BE DEPENDENT ON
WHERE SHOWERS OCCUR DURING THE AFTERNOON. FOR NOW...WILL ADD MVFR
VISIBILITIES AND ALLOW LATER TAF ISSUANCES TO DECIDE IF IFR
VISIBILITIES ARE REQUIRED IN FORECAST.
MID LEVEL CLOUDS WILL MOVE IN ON THURSDAY...WITH SCATTERED
SHOWERS/STORMS EXPECTED BY THE AFTERNOON AGAIN.
.OUTLOOK...THURSDAY NIGHT THROUGH SUNDAY...
RESTRICTIONS CAN BE EXPECTED IN WIDESPREAD SHOWERS AND THUNDERSTORMS
FRIDAY AND FRIDAY NIGHT...WITH MORE ISOLATED COVERAGE EXPECTED
SATURDAY AND SATURDAY NIGHT. SUNDAY SHOULD SEE A RETURN TO VFR
CONDITIONS.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
1132 AM EDT WED AUG 8 2012
.SYNOPSIS...INCREASING HUMIDITY, PLUS A CANADIAN COLD FRONT MOVING
SOUTHWARD TOWARD LAKE ERIE, MAY SPARK SCATTERED THUNDERSTORMS THIS
AFTERNOON AND EVENING AND AGAIN LATE THURSDAY ACROSS THE UPPER
OHIO VALLEY. LOW PRESSURE, COMING EAST FROM MINNESOTA, WILL JOIN
THE COLD FRONT AND BRING MORE NUMEROUS SHOWERS AND THUNDERSTORMS
FRIDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
ALTHOUGH SATELLITE DATA AND NAM MODEL PROFILES SHOW SKIES WILL
STAY MAINLY SUNNY INTO EARLY AFTERNOON. NAM MODEL PROFILES
COMBINED WITH HRRR AND WRF-NMM MODEL OUTPUT, COUPLED WITH RECENT
RADAR DATA, SUGGEST ONCE SURFACE TEMPERATURES REACH THE MID 80S,
CUMULONIMBUS AND THUNDERSTORMS CAN DEVELOP.
HRRR MODEL OUTPUT SPECIFICALLY SHOWS A BAND OF THESE SCATTERED
THUNDERSTORMS CAN MOVE SOUTHEASTWARD ACROSS MUCH OF THE UPPER OHIO
VALLEY THROUGH EARLY EVENING.
STORM INTENSITY WILL NEED MONITORED AS SPC HAS INDICATED SOME
SEVERE POTENTIAL. SREF MODEL OUTPUT SUPPORTS THIS IDEA AS IT SHOWS
INSTABILITY CAN PEAK ABOVE 1500 J/KG AND VERTICAL WIND SHEAR MAY
REACH 30 KTS.
FORECASTED HIGH TEMPERATURES IN THE 85 TO 90 RANGE, BUT THESE
COULD BE REDUCED IF THUNDERSTORMS PASS THROUGH AN AREA PRIOR TO 5
PM.
AFTER DARK, NOCTURNAL COOLING WILL DISSIPATE CONVECTIVE
INSTABILITY. PATCHY RIVER VALLEY FOG CAN AGAIN DEVELOP AS IT HAS
ON PREVIOUS NIGHTS, AN IDEA SUPPORTED BY RECENT GFS LAMP OUTPUT.
FORECASTED LOW TEMPERATURES USING A BLEND OF RECENT NAM AND GFS
MOS.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY/...
COLD FRONT WILL BECOME STALLED IN A WEST TO EAST ORIENTATION
ACROSS THE UPPER OHIO VALLEY THURSDAY AS AN EASTBOUND UPPER LEVEL
SHORTWAVE TROUGH WILL UP THE RISK FOR SHOWERS/STORMS. THIS NEXT UPPER
LEVEL SYSTEM WILL HAVE MORE MOISTURE TO TAP INTO AND HAVE A BIT
MORE OF A PUNCH, SO THERE SHOULD BE AT LEAST SCATTERED
THUNDERSTORMS THURSDAY AND THURSDAY NIGHT.
SPC HAS MAINTAINED A SLIGHT RISK OF SEVERE THUNDERSTORMS THURSDAY
AFTERNOON INTO EARLY FRIDAY, WHICH SREF MODEL OUTPUT PROJECTIONS
OF INSTABILITY AND VERTICAL WIND SHEAR SUPPORT.
A LARGER SYSTEM, BOTH IN THE UPPER LEVELS AND AT THE SFC WILL MOVE
THROUGH THE UPPER OHIO VALLEY FRIDAY, MAKING SHOWERS AND
THUNDERSTORMS LIKELY.
DUE TO THE PROSPECTS FOR SHOWERS AND ACCOMPANYING CLOUDINESS,
CONCURRED WITH GFS AND NAM MOS IN FORECASTING HIGHS THURSDAY NOT AS
WARM AS WEDNESDAY AND THEN COOLER THAN NORMAL FRIDAY. CLOUDS AT
NIGHT AND HUMID CONDITIONS WILL KEEP LOWS WARMER THAN NORMAL.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
BLEND OF RECENT GFS AND ECMWF MODEL OUTPUT SHOWS THE WELL-
DEVELOPED LOW PRESSURE SYSTEM MOVING NORTHWARD PAST THE EASTERN
GREAT LAKES THIS WEEKEND. THIS CAN MAINTAIN WRAP-AROUND SHOWERS
ACROSS THE UPPER OHIO VALLEY AT LEAST THROUGH SATURDAY WITH THE
TREND FOR DRIER CONDITIONS BY SUNDAY.
HIGH PRESSURE COMING EAST FROM THE PLAINS SHOULD PROVIDE A DRY
PERIOD MONDAY AND PERHAPS TUESDAY.
THE EFFECTS OF COOLER TEMPERATURE ALOFT AND INSTABILITY CLOUDS AND
SHOWERS WILL PROVIDE COOLER THAN NORMAL TEMPERATURES THIS WEEKEND.
LESS CLOUDS MONDAY AND TUESDAY SHOULD ALLOW DAYTIME TEMPERATURES
REBOUND TO VALUES NEAR OR SLIGHTLY WARMER THAN NORMAL, AS
INDICATED BY RECENT GFS AND ECMWF MOS.
&&
.AVIATION /15Z WEDNESDAY THROUGH SUNDAY/...
VFR WILL BE PREVALENT INTO TONIGHT. HOWEVER A WEAK SYSTEM MOVING
EASTWARD THROUGH THE AREA THIS AFTERNOON MAY SPAWN A BAND OF
SCATTERED THUNDERSTORM WITH POTENTIAL RESTRICTIONS AND WIND GUSTS
OVER 25 MPH. HOWEVER CONFIDENCE REGARDING COVERAGE AND TIMING IS
STILL TOO LOW TO INCLUDE MENTION IN ANY TAF.
.OUTLOOK...THURSDAY THROUGH SATURDAY...
RESTRICTIONS ARE POSSIBLE IN SHOWERS AND THUNDERSTORMS, AND
PATCHY EARLY MORNING FOG, INTO THE WEEKEND.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS BILLINGS MT
931 AM MDT WED AUG 8 2012
.SHORT TERM...VALID FOR TDY AND THU...
UPDATE TO ZFP AND WRKAFP. A SHORTWAVE WAS SEEN OVER S ID THIS
MORNING ON SATELLITE IMAGERY. RADAR SHOWED A BAND OF SHOWERS WITH
THE WAVE AS WELL. NEW WRF AND RAP BROUGHT LIFT FROM THE WAVE INTO
THE WESTERN MOUNTAINS BY 00Z TONIGHT ALONG WITH SOME
PRECIPITATION. KLVM SOUNDING HAD .74 INCHES OF PRECIPITABLE WATER
SO SOME MOISTURE WILL BE POSSIBLE WITH THUNDERSTORMS. HAVE ADDED
SLIGHT CHANCE POPS TO THE WESTERN MOUNTAINS AND KLVM AREA THIS
AFTERNOON. LOW-LEVEL FLOW WILL TURN EASTERLY E OF KBIL THIS
AFTERNOON AS SURFACE HIGH OVER S SASKATCHEWAN SLIDES INTO THE
DAKOTAS. THIS FLOW WILL CREATE AN INVERSION OVER THE EASTERN ZONES
WHICH WILL SLOW TEMPERATURE RISES. THUS HAVE LOWERED MAX
TEMPERATURES OVER KMLS AND KBHK AREAS. NO CHANGES TO REMAINDER OF
FORECAST. ARTHUR
.LONG TERM...VALID FOR FRI...SAT...SUN...MON...TUE...
MADE A FEW CHANGES TO THE EXTENDED FORECAST AS DETAILS BECOME
MORE VISIBLE AND CONSISTENT. ALTHOUGH LOCATED AT THE APEX OF BROAD
UPPER LEVEL RIDGE THROUGH MUCH OF THE PERIOD...FLATTENED FLOW WILL
ALLOW FOR THE POTENTIAL FOR A FAIRLY ACTIVE PERIOD WITH REGARD TO
PRECIP.
THE EXTENDED PERIOD BEGINS FRIDAY AS A A STRONG TROF CRASHES
THROUGH THE UPPER LEVEL RIDGE. THIS BRINGS OUR BEST CHANCE OF
PRECIPITATION ACROSS THE REGION...AS WELL AS RESULTS IN
FLATTENING THE RIDGE FOR THE REMAINDER OF THE PERIOD. THE ONLY
NEGATIVE IS THAT IT APPEARS TO BE VERY QUICK MOVING. SPLIT THE
00-12Z SATURDAY GRID TO CLEAR OUT WESTERN ZONES MORE QUICKLY
BETWEEN FROM 06-12Z. ALSO TAPERED POPS BACK TO THE EAST FURTHER
FOR THE 12Z-00Z SATURDAY GRID AS A RESULT OF QUICKER PACE OF THE
SYSTEM. PATTERN REMAINS SOMEWHAT ZONAL THROUGH THE BEGINNING OF
NEXT WEEK...WITH SEVERAL WAVES THROUGH THE FLOW. THESE WILL BRING
SLIGHT CHANCES FOR PRECIP...BUT NOTHING TERRIBLY ORGANIZED TAKES
SHAPE UNTIL LATE TUESDAY INTO WEDNESDAY. MODELS ARE STILL
DIFFERING SIGNIFICANTLY ON SPECIFICS OF APPROACHING TROF...BUT
FAVOR MAJOR COOL OFF AND A MORE PROLONGED PERIOD OF PRECIP TO END
THE EXTENDED PERIOD. HAVE INTRODUCED HIGHS IN THE UPPER 80S AND
ABOVE CLIMO TYPE SLIGHT POPS. MODELS SEEM TO SUPPORT MUCH COOLER
TEMPS...AND HIGH POPS POTENTIAL...BUT IS STILL FAR IN THE
FUTURE...AND SYSTEM STILL TAKING SHAPE.
ABOVE NORMAL TEMPERATURES WILL CONTINUE THROUGH THE EXTENDED
PERIOD...BUT LOOK LIKE THEY SHOULD BE MODERATED SOMEWHAT...ONLY IN
LOW 90S FOR MOST PART...DUE TO FLAT FLOW AND MULTIPLE SHORTWAVES
THROUGH THE REGION BRINING CLOUD COVER AND PRECIP. AAG
&&
.AVIATION...
MAINLY VFR CONDITIONS ARE EXPECTED ACROSS THE AREA TODAY. A FEW
SHOWERS AND THUNDERSTORMS ARE EXPECTED TO DEVELOP ACROSS WESTERN
ZONES...NEAR KLVM...THIS AFTERNOON. FLIGHT CONDITIONS COULD BE
LOCALLY LOWERED TO MVFR IN AND AROUND THESE STORMS. A FEW OF
THESE STORMS COULD PRODUCE SOME ERRATIC GUSTY WINDS AS WELL AS
SOME LOCALIZED MOUNTAIN OBSCURATIONS. CHURCH
&&
.PRELIMINARY POINT TEMP/POPS...
TDY THU FRI SAT SUN MON TUE
-------------------------------------------------------
BIL 098 064/094 061/092 061/091 060/094 060/093 059/091
0/U 12/T 23/T 41/B 11/B 21/B 12/T
LVM 095 056/090 053/088 053/088 052/090 051/088 051/087
2/T 33/T 34/T 41/B 22/T 22/T 22/T
HDN 100 062/097 062/095 061/094 061/097 060/096 059/094
0/U 12/T 23/T 41/U 22/T 22/T 12/T
MLS 094 067/096 064/094 064/092 062/094 063/096 062/092
0/U 12/T 22/T 41/B 22/T 22/T 22/T
4BQ 096 063/096 063/093 062/092 061/094 061/094 060/093
0/U 11/B 22/T 42/T 22/T 22/T 22/T
BHK 091 062/091 061/090 061/088 060/089 060/090 061/089
1/U 11/B 22/T 52/T 22/T 22/T 22/T
SHR 095 060/093 058/091 058/089 056/092 057/094 056/090
0/U 01/B 23/T 41/B 22/T 22/T 11/B
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...NONE.
WY...NONE.
&&
$$
WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
604 PM CDT THU AUG 9 2012
.AVIATION...00Z TAFS FOR KOMA...KLNK AND KOFK. COULD BE SCATTERED
CUMULUS CLOUDS AND GUSTS FROM THE NORTH UP TO ABOUT 18KTS THROUGH
01Z...THEN VFR CONDITIONS AFTER THAT WITH CLOUDS DISSIPATING.
COULD SEE SOME MVFR FOG OVERNIGHT...ESPECIALLY AT KOFK AND KOMA
FROM ABOUT 10-14Z. NORTHEAST WINDS AROUND 8KTS AFTER THAT THROUGH
THE REMAINDER OF FRIDAY WITH CUMULUS DEVELOPING AGAIN AROUND 5000
FEET
DEWALD
&&
.PREV DISCUSSION... /ISSUED 305 PM CDT THU AUG 9 2012/
DISCUSSION...
TEMPERATURES WILL PROVIDE THE PRIMARY FORECAST CHALLENGES THROUGH
FRIDAY NIGHT...THEN ATTENTION SHIFTS MORE TOWARD PRECIPITATION
CHANCES OVER THE WEEKEND.
MAIN FEATURES FROM THE 12Z UPPER AIR CHARTS THIS MORNING SHOWED THE
FOLLOWING. AT 300 MB...JETSTREAM CURVED NORTHEAST ACROSS THE PACIFIC
NORTHWEST INTO THE NORTHERN PLAINS...THEN TURNED SOUTHEAST INTO THE
OHIO VALLEY. A JET MAX OF AROUND 100 KNOTS WAS NOTED OVER MINNESOTA.
AT 500 MB...A RATHER IMPRESSIVE CLOSED LOW WAS OVER NORTHEAST
MINNESOTA WITH 12 HOUR HEIGHT FALLS OF 70 METERS NOTED AT KINL. THE
CENTER OF A MID LEVEL RIDGE WAS OVER THE FOUR CORNERS REGION.
COOLER AIR WAS PUSHING DOWN FROM MINNESOTA AND THE EASTERN DAKOTAS
AT 700 MB AND 850 MB.
SURFACE ANALYSIS EARLY THIS AFTERNOON INDICATED A RIDGE OF COOL HIGH
PRESSURE EXTENDING FROM ONTARIO AND MANITOBA DOWN INTO THE NORTHERN
AND WESTERN PLAINS. WINDS WERE MAINLY FROM THE NORTH OVER THE LOCAL
AREA. THAT SURFACE RIDGE WILL BUILD EASTWARD ACROSS THE FORECAST
AREA TONIGHT THROUGH FRIDAY NIGHT...WITH SEASONABLE TEMPERATURES AND
DRY CONDITIONS. EXPECT SOME PATCHY FOG TONIGHT AS WINDS DECREASE...
ESPECIALLY IN PARTS OF OUR CENTRAL AND EASTERN ZONES WHERE SPOTTY
RAIN FELL YESTERDAY AND TUESDAY. EXPECT THAT TO BURN OFF QUICKLY
FRIDAY...IF IT DEVELOPS...WITH SCATTERED CUMULUS MOST AREAS BY THE
AFTERNOON. HIGHS FRIDAY WILL BE IN THE 80S...CLOSE TO NAM MOS.
RETURN FLOW STRENGTHENS LATE FRIDAY NIGHT INTO SATURDAY AND
MODELS ARE IN GENERAL AGREEMENT WITH LARGE SCALE PATTERN. THEY
SHOW SOME 850-700 MB THETA E ADVECTION SPREADING FROM WEST TO EAST
ON SATURDAY. LARGE SCALE FORCING SEEMS WEAK AT BEST...SO KEPT POPS
ONLY AT 20 PERCENT AND TRIED TO CONFINE THOSE TO NORTHEAST
NEBRASKA SATURDAY. A MODEST SHORTWAVE TROUGH DOES MOVE ACROSS THE
PLAINS FOR SATURDAY NIGHT/EARLY SUNDAY...AND THIS IS PROBABLY OUR
BEST CHANCE FOR THUNDERSTORMS. THE 12Z GFS SEEMED WAY TOO GENEROUS
WITH QPF AND ITS OUTPUT WAS GENERALLY NOT USED. FAVORED A BLEND OF
THE NAM AND ECMWF FOR NOW...BUT SHOULD BE ABLE TO ADJUST THINGS
MORE AS WE GET CLOSER WITH 4 KM NAM AND HRRR MODELS. LINGERED SOME
LOW POPS INTO SUNDAY BASED ON CURRENT MODEL TIMING OF FORCING.
OTHERWISE...LOOK FOR DEAMPLIFICATION OF THE 500 MB PATTERN THROUGH
THE WEEKEND AND INTO EARLY NEXT WEEK AS RIDGE SHIFTS FROM THE FOUR
CORNERS REGION TO THE SOUTHERN PLAINS. AS HEIGHTS INCREASE BY MID
WEEK...HIGHS IN THE 90S WILL BECOME COMMON AGAIN.
MILLER
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS BUFFALO NY
702 PM EDT THU AUG 9 2012
.SYNOPSIS...
AN UNUSUALLY STRONG LOW PRESSURE SYSTEM FOR MID AUGUST WILL TRACK
FROM THE OHIO VALLEY TO LAKE ERIE TONIGHT...BEFORE SLOWLY LIFTING
NORTHEAST ACROSS ONTARIO AND QUEBEC FRIDAY THROUGH SUNDAY. THIS
SYSTEM SHOULD BRING SOME MUCH NEEDED RAINFALL TO THE REGION TONIGHT
THROUGH SATURDAY MORNING...WITH SOME LAKE EFFECT RAIN SHOWERS THEN
POSSIBLY AFFECTING AREAS DOWNWIND OF THE LAKES SATURDAY NIGHT AND
SUNDAY.
&&
.NEAR TERM /THROUGH FRIDAY/...
THROUGH EARLY EVENING...THE MOST SIGNIFICANT SHOWERS AND
THUNDERSTORMS HAVE LARGELY STEERED CLEAR OF OUR CWA IN WESTERN NEW
YORK. THIS IS LIKELY TO CHANGE...AS RADAR TRENDS AND THE LATEST
HRRR RUNS SUGGESTS HEAVY RAIN WILL STREAM UP A BOUNDARY EXTENDING
FROM SW-NE FROM EASTERN OHIO...TO NORTHWESTERN NEW YORK...TO WEST-
CENTRAL NEW YORK. FOLLOWING THIS TREND...EXPECT THE GREATEST
POTENTIAL FOR HEAVY RAIN WILL BE IN CATTARAUGUS/ALLEGHENY/LIVINGSTON
COUNTIES. WHILE STORMS SHOULD GRADUALLY WEAKEN WITH THE LOSS OF
DAYTIME HEATING...GIVEN THE UPPER FLOW IS PARALLEL TO THE
DEVELOPING LINE...CAN SEE THE POTENTIALLY FOR LOCALLY HEAVY
RAINFALL IN EXCESS OF TWO INCHES IN THIS REGION. THIS COULD POSE A
THREAT FOR FLASH FLOODING IF THE HRRR FORECAST PANS OUT. UPDATE
INCLUDES MENTION OF HEAVY RAINFALL IN THESE COUNTIES...AND PERHAPS
IN COUNTIES NEARBY THIS EXPANDING FINGER OF MOISTURE.
OTHERWISE...A MORE STRATI-FORM AREA OF SHOWERS ACROSS WESTERN LAKE
ONTARIO WILL DRIFT TO THE NORTHEAST. THIS MAY EXPAND AND CLIP
WESTERN NEW YORK...BUT FEEL QPFS WITH THIS SHOULD LARGELY BE ON
THE LIGHT SIDE COMPARED TO STORMS EXPANDING INTO THE SOUTHERN TIER.
AFTER THAT...ACTIVITY SHOULD BECOME MORE WIDESPREAD...BUT ALSO
MORE STRATIFORM AS THE MAIN SURFACE WAVE LIFTS NORTHEAST INTO
LAKE ERIE...WITH STRENGTHENING WARM AIR ADVECTION AND JET DYNAMICS
OUT AHEAD OF THE LOW HELPING TO FORCE THE DEVELOPMENT OF MORE
WIDESPREAD SHOWERS ACROSS THE AREA...ALONG WITH SOME EMBEDDED
THUNDER GIVEN THE CONTINUED PRESENCE OF ELEVATED INSTABILITY. WILL
HAVE POPS INCREASING TO THE LIKELY AND CATEGORICAL RANGES DURING
THIS TIME FRAME...WITH THE HIGHEST PRECIP CHANCES FOCUSED NORTH OF
THE WARM FRONT...OR ACROSS FAR WESTERN NEW YORK...PORTIONS OF THE
GENESEE VALLEY...AND NORTH COUNTRY.
DURING THE COURSE OF FRIDAY...THE SURFACE LOW WILL LIFT NORTH INTO
SOUTHERN ONTARIO...WITH ITS ASSOCIATED WARM FRONT/BELT OF WARM
ADVECTIVE PRECIP GRADUALLY SHIFTING NORTH INTO ONTARIO AND THE SAINT
LAWRENCE VALLEY WITH TIME. AT THE SAME TIME...ITS TRAILING COLD
FRONT WILL SLIDE EAST INTO FAR WESTERN NEW YORK. COUPLED WITH HEIGHT
FALLS AND AN INCREASINGLY DIFFLUENT FLOW ALOFT ASSOCIATED WITH THE
APPROACHING PARENT UPPER LEVEL LOW...THIS FEATURE WILL LIKELY SET
OFF ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS THAT WILL WORK ACROSS
THE AREA FROM WEST TO EAST FRIDAY AFTERNOON. NEEDLESS TO SAY...ALL
OF THIS WILL RESULT IN RATHER HIGH PRECIPITATION CHANCES CONTINUING
RIGHT THROUGH FRIDAY...WITH A MIX OF HIGH LIKELY TO CATEGORICAL POPS
AGAIN IN THE FORECAST.
IN TERMS OF SEVERE WEATHER POTENTIAL...THIS SHOULD REMAIN RELATIVELY
LOW THIS EVENING WITH THE AREA OF THE GREATEST INSTABILITY REMAINING
LARGELY TO OUR SOUTH AND EAST...THOUGH WE WILL STILL NEED TO KEEP AN
EYE ON ANY ADDITIONAL CONVECTION THAT POPS ALONG OUR SOUTHEASTERN
PERIPHERY. LIKEWISE...DIMINISHING SURFACE-BASED AND MIXED-LAYER
INSTABILITY AFTER SUNSET WILL ALSO RESULT IN THE SEVERE WEATHER
PROBABILITIES REMAINING VERY LOW TONIGHT. AS FOR FRIDAY...FAIRLY
PERSISTENT CLOUD COVER AND MORNING/EARLY AFTERNOON SHOWER ACTIVITY
SHOULD HELP TO HOLD INSTABILITY LEVELS DOWN IN ADVANCE OF THE
APPROACHING COLD FRONT...WHICH SHOULD HELP TO AGAIN LEAD TO A
REDUCED SEVERE RISK. THIS SAID...WE WILL AGAIN NEED TO KEEP AN
EYE ACROSS FAR SOUTHERN PORTIONS OF THE AREA FOR ANY BREAKS/POCKETS
OF BETTER HEATING THAT COULD LEAD TO LOCALIZED STRONGER CONVECTIVE
DEVELOPMENT...ESPECIALLY GIVEN THE PRESENCE OF A MID LEVEL JET
ENCROACHING FROM THE SOUTH.
AS FOR RAINFALL AMOUNTS...IF CURRENT MODEL PROJECTIONS HOLD TRUE...A
CONSENSUS OF THE NAM/GFS/ECMWF AND HPC GUIDANCE SUGGESTS THE
POTENTIAL FOR AS MUCH AS ONE TO ONE AND A HALF INCHES OR RAIN
THROUGH FRIDAY...WITH THE HIGHEST AMOUNTS MOST LIKELY ACROSS
NORTHERN SECTIONS...AND THE LOWEST AMOUNTS MORE PROBABLE ACROSS
INTERIOR PORTIONS OF THE SOUTHERN TIER/FINGER LAKES. GIVEN THE DRY
WEATHER OF THIS SUMMER...SUCH RAINFALL IS LIKELY TO BE LARGELY
BENEFICIAL AND NOT LIKELY TO CAUSE WIDESPREAD FLOODING CONCERNS...
THOUGH HIGHLY LOCALIZED FLOODING ISSUES WOULD STILL BE POSSIBLE
WITHIN INDIVIDUAL STORMS/STRONGER CONVECTIVE ELEMENTS.
&&
.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY NIGHT/...
SHORT TERM MODELS REMAINING CONSISTENT IN SHOWING A DEEP DRY SLOT
SURGING INTO THE REGION ON THE EASTERN SIDE OF THE HIGHLY ANOMALOUS
UPPER CIRCULATION. THIS SHOULD EFFECTIVELY DIMINISH THE STEADIEST
PRECIPITATION FROM WEST TO EAST FRIDAY NIGHT THROUGH SATURDAY.
HOWEVER...WRAP AROUND MOISTURE BEGINS TO WORK INTO WESTERN SECTIONS
DURING THE DAY SATURDAY...EVENTUALLY PUSHING THROUGH EASTERN
SECTIONS BY SATURDAY NIGHT. THE POTENTIAL FOR LAKE EFFECT/ENHANCED
RAINS BECOME INTERESTING SATURDAY NIGHT INTO EARLY SUNDAY...
ESPECIALLY OFF LAKE ERIE AS 850 MB DELTA T VALUES NEAR 15C WITH WELL
ALIGNED WEST SOUTHWEST TRAJECTORIES.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
LATEST MEDIUM RANGE MODELS AND ENSEMBLES IN FAIR AGREEMENT THROUGH
THE PERIOD WHICH IS BASICALLY TO SUGGEST BROAD UPPER LEVEL TROUGHING
ACROSS THE NORTHEAST CONUS...ALTHOUGH THE PERIOD WILL START WITH A
PERIOD OF RIDGING. THE WEAK RIDGING ALOFT AND AT THE SURFACE WILL
PROVIDE DRY CONDITIONS FOR MONDAY. THIS LOOKS TO BE JUST A BRIEF
PERIOD AS ADDITIONAL SHORT WAVE ENERGY DROPS THROUGH THE BROAD
TROUGH BY EARLY TUESDAY WITH A RENEWED THREAT FOR CONVECTION LATE
MONDAY NIGHT AND TUESDAY. ADDITIONAL CHANCES FOR CONVECTION WILL
DEVELOP ALONG AND AHEAD OF THE SURFACE COLD FRONT DROPPING DOWN
ACROSS THE REGION LATE TUESDAY NIGHT AND WEDNESDAY. HIGH PRESSURE
NOSING DOWN IN WAKE OF THE FRONT SHOULD BRING DRIER CONDITIONS FOR
THURSDAY.
&&
.AVIATION /00Z FRIDAY THROUGH TUESDAY/...
AREA RADARS SHOWING SCATTERED POCKETS OF RAIN SHOWERS CONTINUING TO
MOVE NORTHEASTWARD THROUGH PORTIONS OF WESTERN AND NORTHERN NEW YORK
THIS AFTERNOON. AN AREA OF CLEARING WILL BRIEFLY MOVE INTO WESTERN
AND NORTHERN NEW YORK DURING THE MID TO LATE AFTERNOON HOURS
PROVIDING MAINLY VFR CONDITIONS...HOWEVER THIS ADDITIONAL HEATING
WILL TEND TO MAKE THINGS A BIT MORE UNSTABLE AND POSSIBLY LEAD TO
THE DEVELOPMENT OF SOME ISOLATED THUNDERSTORM ACTIVITY. CIGS WILL
THEN THICKEN AND LOWER AGAIN LATER THIS EVENING. VFR CONDITIONS ARE
EXPECTED THROUGH THE EVENING...THEN POSSIBLY GOING MVFR AT TIMES
DURING THE OVERNIGHT HOURS. STEADIER RAIN/MVFR CONDITIONS AFTER 06Z
WILL TAPER OFF TO SCATTERED SHOWERS LATER IN THE MORNING/EARLY
AFTERNOON.
OUTLOOK...
FRIDAY NIGHT...MVFR IN SCATTERED SHOWERS.
SATURDAY...VFR/MVFR IN SCATTERED SHOWERS.
SUNDAY...MAINLY VFR.
MONDAY...VFR.
TUESDAY...VFR...CHANCE OF SHOWERS.
&&
.MARINE...
AN UNUSUALLY STRONG LOW PRESSURE SYSTEM FOR MID AUGUST WILL TRACK
FROM THE OHIO VALLEY TO LAKE ERIE TONIGHT...BEFORE SLOWLY LIFTING
NORTHEAST ACROSS ONTARIO AND QUEBEC FRIDAY THROUGH SUNDAY. THIS
SYSTEM WILL KEEP UNSETTLED WEATHER ACROSS THE LOWER LAKES REGION
THROUGH THE UPCOMING WEEKEND.
IN TERMS OF WINDS AND WAVES...A MORE NORTHWESTERLY TRACK OF THE LOW
COMPARED TO EARLIER PROJECTIONS WILL LEAD TO A SOMEWHAT WEAKER
EASTERLY TO NORTHEASTERLY FLOW ON LAKE ONTARIO LATER TONIGHT AND
FRIDAY MORNING...WHICH SHOULD RESULT IN CONDITIONS REMAINING BELOW
SMALL CRAFT ADVISORY CRITERIA THROUGH THAT TIME. WINDS WILL THEN
VEER TO SOUTHERLY ON FRIDAY FOLLOWING THE PASSAGE OF A WARM
FRONT...BEFORE TURNING SOUTHWESTERLY AND STRENGTHENING FRIDAY NIGHT
AND SATURDAY IN THE WAKE OF A COLD FRONT. COUPLED WITH THE ARRIVAL
OF COOLER AIR ALOFT...THIS MAY LEAD TO ADVISORY-LEVEL CONDITIONS
DEVELOPING ACROSS PORTIONS OF THE LAKES FRIDAY NIGHT AND SATURDAY.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...JJR
NEAR TERM...APFFEL/JJR
SHORT TERM...TMA
LONG TERM...TMA
AVIATION...JM/SMITH
MARINE...JJR
AREA FORECAST DISCUSSION
NWS BUFFALO NY
543 PM EDT WED AUG 8 2012
.SYNOPSIS...
A WEAK COLD FRONT WILL MOVE ACROSS OUR AREA BY EARLY THIS
EVENING...WITH SCATTERED SHOWERS AND THUNDERSTORMS ACCOMPANYING ITS
PASSAGE. MAINLY DRY WEATHER WILL THEN FOLLOW THE FRONT TONIGHT...
BEFORE LOW PRESSURE LIFTS NORTHEAST FROM THE OHIO VALLEY THURSDAY
AND FRIDAY AND BRINGS INCREASINGLY UNSETTLED CONDITIONS.
&&
.NEAR TERM /THROUGH THURSDAY/...
AS OF 2100Z...A SLOW MOVING FRONTAL BOUNDARY WAS JUST SOUTH OF A
BUFFALO TO ROCHESTER TO WATERTOWN LINE. THIS CAN BE SEEN BOTH WITH
SURFACE OBSERVATIONS...AND THE BOUNDARY SHOWS UP VERY NICELY ON
THE MONTAGUE RADAR. THIS FRONT COMBINED WITH LAKE BREEZES HAS
SPAWNED SOME SHOWERS AND THUNDERSTORMS OUT AHEAD OF THE BOUNDARY.
THE HRRR CAPTURES THIS QUITE WELL...AND SUGGESTS A WEAKENING TREND
AS THESE CELLS MOVE TO THE EAST AT ABOUT 20 MPH. GRIDS AND ZONES
WERE UPDATED TO REFLECT THE LATEST RADAR TRENDS.
FOLLOWING THE PASSAGE OF THE FRONT...THE LOSS OF BOTH LOW LEVEL
CONVERGENCE AND DAYTIME HEATING SHOULD BRING AN END TO THE PRECIP
DURING THE EARLY TO MID EVENING HOURS...WITH GENERALLY DRY WEATHER
THEN EXPECTED TO FOLLOW FOR THE BALANCE OF THE NIGHT. WITH
SCATTERED LOWER CLOUDS REMAINING IN PLACE AND MID AND HIGH CLOUDS
INCREASING OVERNIGHT IN ADVANCE OF THE NEXT LOW...AT THIS POINT DO
NOT EXPECT FOG TO BE A SIGNIFICANT FORECAST CONCERN OVERNIGHT.
ON THURSDAY...CLOUDS WILL CONTINUE TO INCREASE AND THICKEN ACROSS
THE AREA FROM SOUTHWEST TO NORTHEAST AS UPPER TROUGHING TAKES SHAPE
ACROSS THE GREAT LAKES...AND AN ATTENDANT SURFACE LOW DEVELOPS AND
LIFTS NORTHEAST ACROSS THE OHIO VALLEY. WITH DIURNAL HEATING...THE
FRONTAL BOUNDARY STALLED OUT JUST TO OUR SOUTH MAY BECOME THE FOCUS
FOR ANOTHER ROUND OF SCATTERED CONVECTION ACROSS THE SOUTHERN TIER
AND FINGER LAKES DURING THE AFTERNOON...BEFORE THE MAIN SURFACE WAVE
DRAWS CLOSE ENOUGH TO BRING INCREASING SHOWER/THUNDERSTORM CHANCES
TO THE REST OF THE REGION LATER IN THE DAY. WILL CONTINUE TO
INDICATE A NORTHEAST-SOUTHWEST GRADIENT IN PRECIP CHANCES ACROSS THE
REGION TOMORROW AFTERNOON...RANGING FROM SLIGHT CHANCE/LOW CHANCE
ACROSS THE SAINT LAWRENCE VALLEY AND NORTH COUNTRY...TO HIGH CHANCE
ACROSS THE SOUTHERN TIER AND FAR WESTERN NEW YORK. WITH THE BEST
INSTABILITY REMAINING ALONG AND SOUTH OF THE FRONT AND ANY STRONGER
WIND FIELDS ALOFT REMAINING TO ITS NORTH...AT THIS POINT OUR SEVERE
WEATHER POTENTIAL FOR TOMORROW AFTERNOON LOOKS TO BE RELATIVELY LOW.
AS FOR TEMPERATURES...READINGS WILL AGAIN BE A LITTLE MILDER TONIGHT
THAN LAST NIGHT...WITH LOWS RANGING FROM THE UPPER 50S/NEAR 60
ACROSS INTERIOR PORTIONS OF THE SOUTHERN TIER AND NORTH COUNTRY TO
THE MID 60S ACROSS THE LAKE PLAINS. WITH 850 MB TEMPS OF +14C TO
+16C AND INCREASING CLOUD COVER/PRECIP CHANCES THEN EXPECTED ON
THURSDAY...DAYTIME HIGHS SHOULD RANGE FROM THE LOWER TO MID 80S IN
MOST LOCATIONS.
&&
.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY NIGHT/...
MUCH NEEDED BENEFICIAL RAINS CONTINUING TO LOOK PROMISING DURING THE
THURSDAY NIGHT THROUGH FRIDAY NIGHT TIME FRAME...AS POTENT UPPER
LEVEL LOW DROPS THROUGH THE GREAT LAKES. NAM/CANADIAN/GFS ALL ON
BOARD IN CONTINUING TO DEVELOP INCREASING RAIN AREA...ALONG WITH
SOME EMBEDDED STRONGER CONVECTION WITH THE INCREASING MID LEVEL
FRONTOGENESIS AND SUBSTANTIAL HEIGHT FALLS TAKING PLACE.
PRECIPITATION PATTERN LOOKS TO BECOME EVEN MORE FOCUSED LATE
THURSDAY NIGHT AND FRIDAY. THE LOW/MID LEVEL BAROCLINIC ZONE
EXTENDING ACROSS NEW YORK STATE WILL UNDERGO SIGNIFICANT
FRONTOGENESIS AND DEEPEN IN RESPONSE TO INCREASING UPPER LEVEL
DIVERGENCE AND INTENSE LARGE SCALE ASCENT JUST AHEAD OF THE PV
ANOMALY...ALLOWING RAIN/EMBEDDED THUNDER TO INCREASE IN
COVERAGE/INTENSITY. PLACEMENT OF HEAVIEST PRECIPITATION AXIS WILL BE
A TOUGH CALL WITH STILL SOME MODEL DISCREPANCIES IN THE EXACT TRACK
OF THE UPPER LEVEL LOW AND SUBSEQUENT SURFACE WAVE...AS WELL AS A
MODEL AGREEMENT OF THE PRESENCE OF A SHARP DRY SLOT NOSING INTO A
PORTION OF THE AREA. PRECIPITABLE WATER VALUES ACROSS THE ENTIRE
AREA WILL BE RUNNING IN THE 1.5 TO 1.75 INCH RANGE. EXPECTATIONS ARE
THAT A GENERAL WIDESPREAD 0.75 TO 1.25 INCHES OF RAIN WILL
OCCUR...WITH HEAVIER AMOUNTS NEARING 2 INCHES VERY POSSIBLE ACROSS
EASTERN SECTIONS OF THE AREA WHERE MODELS DO NOT PLACE ANY
SIGNIFICANT DRY SLOTTING.
THE STEADIEST PRECIPITATION SHOULD DROP OF FRIDAY NIGHT AND SATURDAY
AS DEEP DRY SLOT WORKS INTO THE AREA BEHIND THE LOW AS IT PUSHES
INTO ONTARIO. HOWEVER...WRAP AROUND MOISTURE BEGINS TO WORK INTO
WESTERN SECTIONS DURING THE DAY SATURDAY...EVENTUALLY PUSHING
THROUGH EASTERN SECTIONS BY SATURDAY NIGHT.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
HEIGHTS BEGIN TO RISE IN THE WAKE OF THE UPPER LOW FOR THE SECOND
HALF OF THE WEEKEND. A LINGERING CYCLONIC FLOW OVER EASTERN SECTIONS
OF THE AREA COULD TOUCH OFF A FEW SHOWERS...OTHERWISE THE OVERALL
TREND IS TO DRY THINGS OUT FROM WEST TO EAST. HEIGHTS CONTINUING TO
RISE THROUGH MID WEEK. FOR THE MOST PART EXPECT DRY WEATHER...
ALTHOUGH GLOBAL MODELS SUGGESTING A COUPLE OF WEAK SHORT WAVES
CROSSING THE REGION IN THE NORTHWEST FLOW ALOFT. HOWEVER...THESE
MODELS DIFFER IN INTENSITY AND TRACK OF THE INDIVIDUAL WAVE WAND
CONFIDENCE IS LOW THAT MUCH ACTIVITY WILL BE GENERATED...OTHER THAN
SOME SPOTTY DIURNALLY DRIVEN CONVECTION.
&&
.AVIATION /21Z WEDNESDAY THROUGH MONDAY/...
AS OF 2100Z...THE SLOW-MOVING COLD FRONTAL BOUNDARY IS DRAPED ACROSS
THE LOWER GREAT LAKES AND FAR WESTERN NEW YORK. THE FRONT IS
ALREADY THROUGH ALL TAF LOCATIONS...WITH A MINIMAL CHANCE FOR
THUNDERSTORMS FOR THE REMAINDER OF THE EVENING.
ONCE THE FRONT PASSES THROUGH THE AREA...EXPECT A GRADUAL INCREASE
IN MID AND HIGH LEVEL CLOUDINESS EXPECTED OVERNIGHT. COUPLED WITH
LINGERING SCATTERED LOWER VFR CLOUDS...THESE SHOULD HELP REDUCE
THE RISK OF FOG OVERNIGHT.
ON THURSDAY...CLOUD COVER WILL CONTINUE TO THICKEN ACROSS THE AREA
THROUGH THE DAY IN ADVANCE OF LOW PRESSURE LIFTING NORTHEAST
ACROSS THE OHIO VALLEY. EXPECT THE MORNING TO BE LARGELY
DRY...WITH CONVECTIVE CHANCES THEN SLOWLY INCREASING DURING THE
AFTERNOON AS THE LOW APPROACHES THE AREA AND DAYTIME INSTABILITY
DEVELOPS. AS THE BULK OF ANY PRECIP WILL BE SCATTERED INITIALLY
AND SHOULD HOLD OFF UNTIL CLOSE TO OR AFTER 18Z...FOR NOW HAVE
ELECTED TO LEAVE THE TAFS DRY LATE IN THE PERIOD.
OUTLOOK...
THURSDAY NIGHT AND FRIDAY...IFR/MVFR IN RAIN WITH SCATTERED
THUNDERSTORMS.
SATURDAY...VFR/MVFR WITH A CHANCE OF SHOWERS AND THUNDERSTORMS.
SUNDAY...MAINLY VFR.
MONDAY...VFR.
&&
.MARINE...
A WEAK COLD FRONT WILL MOVE FINISH CROSSING THE LOWER LAKES BY
EARLY THIS EVENING... WITH SCATTERED SHOWERS AND THUNDERSTORMS
ACCOMPANYING ITS PASSAGE. MAINLY DRY WEATHER WILL THEN FOLLOW THE
FRONT TONIGHT...BEFORE LOW PRESSURE LIFTS NORTHEAST FROM THE OHIO
VALLEY THURSDAY AND FRIDAY AND BRINGS INCREASINGLY UNSETTLED
CONDITIONS...INCLUDING THE THREAT OF SCATTERED THUNDERSTORMS.
IN TERMS OF WINDS AND WAVES...GENERALLY LIGHT TO MODEST WINDS TO
CONTINUE THROUGH THURSDAY...WITH WAVES REMAINING UNDER 2 FEET. AFTER
THAT TIME...A STRENGTHENING NORTH TO NORTHEASTERLY FLOW WILL BRING A
RISK OF ADVISORY LEVEL WINDS AND WAVES TO WESTERN LAKE ONTARIO BY
FRIDAY MORNING.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...JJR
NEAR TERM...APFFEL/JJR
SHORT TERM...TMA
LONG TERM...TMA
AVIATION...JJR
MARINE...JJR
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
1050 PM EDT THU AUG 9 2012
.SYNOPSIS...
A TROUGH OF LOW PRESSURE OVER THE PIEDMONT THIS AFTERNOON THROUGH
FRIDAY WILL GIVE WAY TO A COLD FRONT ON SATURDAY. HIGH PRESSURE
WILL BUILD INTO THE AREA EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1045 PM THURSDAY...CONTINUED MAIN DILEMMA FOR THE OVERNIGHT
PERIOD WILL BE THE TIMING AND COVERAGE OF THE CONVECTIVE ACTIVITY
APPROACHING FROM THE SOUTHWEST. VARIOUS MODEL BUFR SOUNDINGS
INDICATE AN INCREASE IN MOISTURE THIS EVENING AND OVERNIGHT VIA PWS
REBOUNDING BACK OVER 2+ INCHES. WEAK MID LEVEL SHEARED VORT AND AN
UPPER LEVEL JET MAX TO TRACK NE ACROSS THE CAROLINAS TONIGHT...WITH
THE RIGHT REAR QUADRANT OF THIS UPPER JET AND SOURCE OF UPPER LEVEL
DIVERGENCE TO PUSH ACROSS OR AFFECT THE FA MAINLY AFTER MIDNIGHT
TONIGHT. THE RR QUAD WILL BE A FAVORED AREA OF UVVS AND AS A RESULT
WILL INCREASE POPS TO GOOD CHANCE OR POSSIBLY LIKELY LEADING TO BUT
MAINLY OCCURRING AFTER MIDNIGHT TONIGHT. THE DAYS HEATING COMBINED
WITH DYNAMICS ALOFT HAS HELPED CONVECTION REACH SVR CRITERIA WELL
UPSTREAM FROM THE FA. THE DAYS INSOLATION WILL BE DONE-WITH BY THE
TIME THE BULK OF THE PCPN PUSHES TO/ACROSS THE ILM CWA LATER
TONIGHT...AND AS A RESULT DO NOT ANTICIPATE PULSING SVR ACTIVITY.
HOWEVER...DO LIKE THE HEAVY RAIN/GUSTY WINDS TO SUFFIX AFTER THE
MENTIONING OF THE CONVECTION OVERNIGHT. EXPECT 20-30 MPH STORM
MOTIONS...WHICH SHOULD HELP LOWER THE FLOOD POTENTIAL. HOWEVER...IF
ACTIVITY BEGINS TO TRAIN...THEN WILL HAVE TO REVISIT THE FLOOD
ISSUE. AS FOR MIN TEMPS...WILL STAY ON THE HIGHER SIDE OF MOS
GUIDANCE DUE TO SKIES HAVING CLOUDED UP ALONG WITH THE POTENTIAL
MORNING OCCURRENCE OF PCPN.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 2 PM THURSDAY...AN AMPLIFYING H5 TROUGH...APPROACHING COLD
FRONT AND PRECIPITABLE WATER SURGING ABOVE 2 INCHES WILL RESULT IN
AN UNSETTLED SHORT TERM PERIOD. THE FRONT IS EXPECTED TO STALL IN
THE VICINITY AS IT BECOMES ORIENTED WITH THE FLOW ALOFT. THUS THE
FORECAST INDICATES CHANCE TO LIKELY POPS THROUGH SATURDAY NIGHT.
FAVORED THE COOLER MET NUMBERS EACH DAY GIVEN THE EXPECTED CLOUD
COVER. THE CLOUD COVER COULD ALSO LIMIT DEEPER CONVECTION FROM
DEVELOPING...HOWEVER HEATING WILL LIKELY LEAD TO AT LEAST MODERATE
INSTABILITY.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
AS OF 2 PM THURSDAY...COLD FRONT WILL BE MOVING OFFSHORE WHILE
DISSIPATING AT THE START OF THE PERIOD. THIS WILL BRING AN END TO
PRECIP THROUGH SUNDAY AFTN AS DRIER AND COOLER AIR WORKS IN BEHIND
THIS BOUNDARY. FORECAST SOUNDINGS SUGGEST CLEARING WILL OCCUR
RAPIDLY DURING SUNDAY...BUT EVEN WITH AMPLE SUNSHINE...TEMPS WILL
STRUGGLE TO CLIMO AS SOME COOL ADVECTION OCCURS THROUGH MAX HEATING.
EXPECT TEMPS AT OR JUST BELOW 90 SUNDAY WITH MINS FALLING TO NEAR 70.
UPPER TROUGH WEAKENS AND SPINS OFF TO THE NORTHEAST AS SUBTLE
RIDGING DEVELOPS ACROSS THE SOUTHEAST. RISING 1000-500MB THICKNESSES
AND WARMING MID-LEVEL TEMPS WILL COMBINE WITH DRY W/NW FLOW TO
PREVENT WIDESPREAD CONVECTION MON EVEN WITH SLIGHTLY STEEPENED ML
LAPSE RATES. MOISTURE RETURN IS SLOW TO DEVELOP TUESDAY...BUT SOME
GUIDANCE INDICATING THAT A COASTAL TROUGH MAY HELP SPREAD SOME
MOISTURE TOWARDS THE COAST AND WILL BUMP POP TO CHC TUESDAY...ACROSS
THE EAST. TEMPS WILL REMAIN AROUND CLIMO...A FEW DEGREES EITHER SIDE
OF 90 AND 70.
FOR THE MID/LATE WEEK...BROAD TROUGHING REMAINS ACROSS THE EAST
WHILE WEAK IMPULSES MAY SPAWN AFTERNOON STORMS EACH DAY.
HOWEVER...WITH MID LEVEL DRY AIR PERSISTING...CONVECTION WILL BE
CAPPED AT SCHC/SILENT THIS FAR OUT IN TIME. A REINFORCING SHOT OF
COOL/DRY AIR MAY PUSH THROUGH THURSDAY AS UPPER VORT MOVES ACROSS
NEW ENGLAND WHICH WILL HELP KEEP TEMPS RIGHT AROUND CLIMO THROUGH
THE END OF THE PERIOD.
&&
.AVIATION /00Z FRIDAY THROUGH TUESDAY/...
AS OF 00Z...EXPECT TSRA AT FLO/MYR/CRE AND RW AT LBT AROUND 04Z AS
PRECIP MOVES IN FROM THE SW. CONFIDENCE IN TIMING NOT REAL HIGH.
PRECIP MOVS NE W/BEST CHC TSRA NR ILM 09Z. TEMPO MVFR LIKELY WITH
PRECIP. WILL NOT INCLUDE IFR DUE TO SCT NATURE OF ACTIVITY...BUT
SHORT TERM IFR PSBL IF CELL MOVES OVR A TERM. AT FLO/LBT MVFR
CIGS/VSBYS IN BR 08-09Z. PRECIP RE-DEVELOPS BTWN COAST TERMS AND
INLAND TERMS BY 18Z. MOD CONFIDENCE TEMPO IFR/TS PSBL MAINLY COAST
TERMS 18-00Z AS SHORT WAVE MOVS THROUGH. LOW CONFIDENCE TS AT
FLO/LBT 18-00Z.
EXTENDED OUTLOOK...CHANCE OF MORNING MVFR VSBYS IN BR WITH A CHANCE
OF SHOWERS AND THUNDERSTORMS THROUGH SUNDAY. VFR MONDAY.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 1045 PM THURSDAY...PROGGED SFC PRESSURE PATTERN AND TIGHTENING
GRADIENT...WILL YIELD WINDS FROM SSW-SW THIS EVENING AND
OVERNIGHT...ALONG WITH SPEEDS INCREASING FROM AROUND 15 KT...EXCEPT
15-20 KT FOR THE ILM NC WATERS. SIGNIFICANT SEAS ...MAINLY FROM WIND
DRIVEN 3-5 SECOND PERIOD WAVES...WILL BUILD TO 3 TO 5 FT NORTH OF
LITTLE RIVER INLET...AND 2 TO 4 FT SOUTH OF THE INLET. SEAS ARE
EXPECTED TO BUILD TO 4 TO 6 FT FOR THE ILM NC WATERS FRIDAY...WITH
SW WINDS 15-20 KT. STILL NOT ALL THAT CONFIDENT AT THE MOMENT WITH
REGARD TO RAISING A SCA/SCEC. IF DATA FROM TONIGHTS 00Z EARLY MODEL
RUNS INDICATE THIS INCREASED SCA POTENTIAL...MAY GO AHEAD AND ISSUE
A SCA OR SCEC AT THE LATE NIGHT UPDATE.
SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 2 PM THURSDAY...SOUTH-SOUTHWEST FETCH WILL BE IN PLACE THROUGH
THE BULK OF THE SHORT TERM PERIOD. IT APPEARS THE PRESSURE GRADIENT
WILL BE AT ITS GREATEST LATE FRIDAY AFTERNOON INTO THE EVENING. THE
FLOW WILL FINALLY BEGIN TO WEAKEN SATURDAY NIGHT WITH THE FRONT IN
THE VICINITY. SEAS MAY REACH MARGINAL SMALL CRAFT THRESHOLDS BY
FRIDAY EVENING...WITH EXERCISE CAUTION CONDITIONS EXPECTED DURING
THE MAJORITY OF THE PERIOD.
LONG TERM /SUNDAY THROUGH TUESDAY/...
AS OF 2 PM THURSDAY...PREDOMINANT SW FLOW TO PERSIST THROUGH THE
EXTENDED AS BERMUDA HIGH RIDGES IN FROM THE EAST. A FAIRLY WEAK
PRESSURE GRADIENT WILL EXIST HOWEVER...SO WINDS WILL BE AROUND 10
KTS OR LESS THROUGH MUCH OF THE PERIOD. THE LIGHT WINDS WILL PRODUCE
A 2-3FT/5SEC SW WIND CHOP WHICH WILL COMBINE WITH A 2FT/9SEC SE
SWELL TO PRODUCE OVERALL WAVE HEIGHTS OF 2-3 FT.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...DOUGH
SHORT TERM...STEVE
LONG TERM...JOSH
AVIATION...JOSHUA
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
655 PM EDT THU AUG 9 2012
.SYNOPSIS...
A TROUGH OF LOW PRESSURE OVER THE PIEDMONT THIS AFTERNOON THROUGH
FRIDAY WILL GIVE WAY TO A COLD FRONT ON SATURDAY. HIGH PRESSURE
WILL BUILD INTO THE AREA EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 645 PM THURSDAY...MAIN DILEMMA FOR THE TONIGHT PERIOD WILL BE
THE TIMING AND COVERAGE OF THE CONVECTIVE ACTIVITY APPROACHING FROM
THE SOUTHWEST. VARIOUS MODEL BUFR SOUNDINGS INDICATE AN INCREASE IN
MOISTURE THIS EVENING AND OVERNIGHT VIA PWS REBOUNDING BACK OVER 2+
INCHES. WEAK MID LEVEL SHEARED VORT AND AN UPPER LEVEL JET MAX TO
TRACK NE ACROSS THE CAROLINAS TONIGHT...WITH THE RIGHT REAR QUADRANT
OF THIS UPPER JET AND SOURCE OF UPPER LEVEL DIVERGENCE TO PUSH
ACROSS OR AFFECT THE FA MAINLY AFTER MIDNIGHT TONIGHT. THE RR QUAD
WILL BE A FAVORED AREA OF UVVS AND AS A RESULT WILL INCREASE POPS TO
GOOD CHANCE OR POSSIBLY LIKELY LEADING TO BUT MAINLY OCCURRING AFTER
MIDNIGHT TONIGHT. THE DAYS HEATING COMBINED WITH DYNAMICS ALOFT HAS
HELPED CONVECTION REACH SVR CRITERIA WELL UPSTREAM FROM THE FA. THE
DAYS INSOLATION WILL BE DONE-WITH BY THE TIME THE BULK OF THE PCPN
PUSHES TO/ACROSS THE ILM CWA LATER TONIGHT...AND AS A RESULT DO NOT
ANTICIPATE PULSING SVR ACTIVITY. HOWEVER DO LIKE THE HEAVY
RAIN/GUSTY WINDS TO SUFFIX AFTER THE MENTIONING OF CONVECTION
OVERNIGHT. EXPECT 10-15 MPH STORM MOTIONS...WHICH SHOULD HELP LOWER
THE FLOOD POTENTIAL. HOWEVER...IF ACTIVITY BEGINS TO TRAIN...THEN
WILL HAVE TO REVISIT THE FLOODING ISSUE. AS FOR MIN TEMPS...WILL
STAY ON THE HIGHER SIDE OF MOS GUIDANCE DUE TO SKIES CLOUDING UP
ALONG WITH THE OCCURRENCE OF PCPN.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 2 PM THURSDAY...AN AMPLIFYING H5 TROUGH...APPROACHING COLD
FRONT AND PRECIPITABLE WATER SURGING ABOVE 2 INCHES WILL RESULT IN
AN UNSETTLED SHORT TERM PERIOD. THE FRONT IS EXPECTED TO STALL IN
THE VICINITY AS IT BECOMES ORIENTED WITH THE FLOW ALOFT. THUS THE
FORECAST INDICATES CHANCE TO LIKELY POPS THROUGH SATURDAY NIGHT.
FAVORED THE COOLER MET NUMBERS EACH DAY GIVEN THE EXPECTED CLOUD
COVER. THE CLOUD COVER COULD ALSO LIMIT DEEPER CONVECTION FROM
DEVELOPING...HOWEVER HEATING WILL LIKELY LEAD TO AT LEAST MODERATE
INSTABILITY.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
AS OF 2 PM THURSDAY...COLD FRONT WILL BE MOVING OFFSHORE WHILE
DISSIPATING AT THE START OF THE PERIOD. THIS WILL BRING AN END TO
PRECIP THROUGH SUNDAY AFTN AS DRIER AND COOLER AIR WORKS IN BEHIND
THIS BOUNDARY. FORECAST SOUNDINGS SUGGEST CLEARING WILL OCCUR
RAPIDLY DURING SUNDAY...BUT EVEN WITH AMPLE SUNSHINE...TEMPS WILL
STRUGGLE TO CLIMO AS SOME COOL ADVECTION OCCURS THROUGH MAX HEATING.
EXPECT TEMPS AT OR JUST BELOW 90 SUNDAY WITH MINS FALLING TO NEAR 70.
UPPER TROUGH WEAKENS AND SPINS OFF TO THE NORTHEAST AS SUBTLE
RIDGING DEVELOPS ACROSS THE SOUTHEAST. RISING 1000-500MB THICKNESSES
AND WARMING MID-LEVEL TEMPS WILL COMBINE WITH DRY W/NW FLOW TO
PREVENT WIDESPREAD CONVECTION MON EVEN WITH SLIGHTLY STEEPENED ML
LAPSE RATES. MOISTURE RETURN IS SLOW TO DEVELOP TUESDAY...BUT SOME
GUIDANCE INDICATING THAT A COASTAL TROUGH MAY HELP SPREAD SOME
MOISTURE TOWARDS THE COAST AND WILL BUMP POP TO CHC TUESDAY...ACROSS
THE EAST. TEMPS WILL REMAIN AROUND CLIMO...A FEW DEGREES EITHER SIDE
OF 90 AND 70.
FOR THE MID/LATE WEEK...BROAD TROUGHING REMAINS ACROSS THE EAST
WHILE WEAK IMPULSES MAY SPAWN AFTERNOON STORMS EACH DAY.
HOWEVER...WITH MID LEVEL DRY AIR PERSISTING...CONVECTION WILL BE
CAPPED AT SCHC/SILENT THIS FAR OUT IN TIME. A REINFORCING SHOT OF
COOL/DRY AIR MAY PUSH THROUGH THURSDAY AS UPPER VORT MOVES ACROSS
NEW ENGLAND WHICH WILL HELP KEEP TEMPS RIGHT AROUND CLIMO THROUGH
THE END OF THE PERIOD.
&&
.AVIATION /00Z FRIDAY THROUGH TUESDAY/...
AS OF 00Z...EXPECT TSRA AT FLO/MYR/CRE AND RW AT LBT AROUND 04Z AS
PRECIP MOVES IN FROM THE SW. CONFIDENCE IN TIMING NOT REAL HIGH.
PRECIP MOVS NE W/BEST CHC TSRA NR ILM 09Z. TEMPO MVFR LIKELY WITH
PRECIP. WILL NOT INCLUDE IFR DUE TO SCT NATURE OF ACTIVITY...BUT
SHORT TERM IFR PSBL IF CELL MOVES OVR A TERM. AT FLO/LBT MVFR
CIGS/VSBYS IN BR 08-09Z. PRECIP RE-DEVELOPS BTWN COAST TERMS AND
INLAND TERMS BY 18Z. MOD CONFIDENCE TEMPO IFR/TS PSBL MAINLY COAST
TERMS 18-00Z AS SHORT WAVE MOVS THROUGH. LOW CONFIDENCE TS AT
FLO/LBT 18-00Z.
EXTENDED OUTLOOK...CHANCE OF MORNING MVFR VSBYS IN BR WITH A CHANCE
OF SHOWERS AND THUNDERSTORMS THROUGH SUNDAY. VFR MONDAY.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 645 PM THURSDAY...PROGGED SFC PRESSURE PATTERN AND TIGHTENING
GRADIENT...WILL PRODUCE WINDS VEERING TO THE SSW-SW THIS EVENING AND
OVERNIGHT...ALONG WITH SPEEDS INCREASING TO AROUND 15 KT...EXCEPT
15-20 KT FOR THE ILM NC WATERS...AFTER MIDNIGHT. SIGNIFICANT SEAS
...MAINLY FROM WIND DRIVEN 3-5 SECOND PERIOD WAVES...WILL BUILD TO 3
TO 5 FT NORTH OF LITTLE RIVER INLET...AND 2 TO 4 FT SOUTH OF THE
INLET. SEAS ARE EXPECTED TO BUILD TO 4 TO 6 FT FOR THE ILM NC WATERS
FRIDAY...WITH SW WINDS 15-20 KT. STILL NOT ALL THAT CONFIDENT AT THE
MOMENT WITH REGARD TO RAISING A SCA/SCEC. IF DATA FROM TONIGHTS 00Z
EARLY MODEL RUNS INDICATE THIS INCREASED SCA POTENTIAL...MAY GO
AHEAD AND ISSUE A SCA OR SCEC AT THE LATE NIGHT UPDATE.
SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 2 PM THURSDAY...SOUTH-SOUTHWEST FETCH WILL BE IN PLACE THROUGH
THE BULK OF THE SHORT TERM PERIOD. IT APPEARS THE PRESSURE GRADIENT
WILL BE AT ITS GREATEST LATE FRIDAY AFTERNOON INTO THE EVENING. THE
FLOW WILL FINALLY BEGIN TO WEAKEN SATURDAY NIGHT WITH THE FRONT IN
THE VICINITY. SEAS MAY REACH MARGINAL SMALL CRAFT THRESHOLDS BY
FRIDAY EVENING...WITH EXERCISE CAUTION CONDITIONS EXPECTED DURING
THE MAJORITY OF THE PERIOD.
LONG TERM /SUNDAY THROUGH TUESDAY/...
AS OF 2 PM THURSDAY...PREDOMINANT SW FLOW TO PERSIST THROUGH THE
EXTENDED AS BERMUDA HIGH RIDGES IN FROM THE EAST. A FAIRLY WEAK
PRESSURE GRADIENT WILL EXIST HOWEVER...SO WINDS WILL BE AROUND 10
KTS OR LESS THROUGH MUCH OF THE PERIOD. THE LIGHT WINDS WILL PRODUCE
A 2-3FT/5SEC SW WIND CHOP WHICH WILL COMBINE WITH A 2FT/9SEC SE
SWELL TO PRODUCE OVERALL WAVE HEIGHTS OF 2-3 FT.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...DOUGH
SHORT TERM...STEVEP
LONG TERM...JOSHW
AVIATION...MIKER
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
610 PM EDT WED AUG 8 2012
.SYNOPSIS...
SCATTERED SHOWERS AND THUNDERSTORMS WILL CONTINUE THROUGH THE
EVENING. ONLY WIDELY SCATTERED SHOWERS AND THUNDERSTORMS ARE
EXPECTED THURSDAY WITH BETTER CHANCES EXPECTED FRIDAY. A COLD FRONT
WILL ALLOW THE CHANCE OF STORMS TO CONTINUE ON SATURDAY. HIGH
PRESSURE WILL BUILD INTO THE AREA EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 6:00 PM WEDNESDAY...HAVE FIRED OUT A QUICK UPDATE TO GO WITH
CATEGORICAL POPS FOR NORTHWESTERN COUNTIES AS CONVECTION APPEARS TO
BE ORGANIZING. HRRR HAS THE ACTIVITY CAPTURED WELL AND MAINTAINS IT
FOR SEVERAL HOURS. DAYTIME HEATING HAS ALLOWED THE TEMPERATURES TO
RISE TO THE UPPER 80S IN THESE AREAS PROVIDING AMPLE SURFACE BASED
INSTABILITY. HRRR/1800 UTC GFS AND NAM SHOW THIS WILL BE ALL THE
ACTIVITY AND THEREFORE REMOVED POPS FOR THE REMAINDER OF THE AREA
AFTER AROUND 0400 UTC.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 3 PM WEDNESDAY...THE NEXT H5 TROUGH WILL DEVELOP ACROSS THE
MS VALLEY THU AS AN UPPER LOW DIVES SOUTH FROM THE WESTERN GREAT
LAKES REGION. THE RESULT WILL BE A HIGHLY AMPLIFIED/ANOMALOUS TROUGH
ALOFT OVER THE EASTERN UNITED STATES BY FRIDAY. THE TROUGH WILL PUSH
A COLD FRONT TOWARD THE FORECAST AREA LATE FRIDAY. THE PRECIPITABLE
WATER WILL ALSO INCREASE TO 2+INCHES FRIDAY AHEAD OF THE FRONT ALONG
WITH SUFFICIENT INSTABILITY THE BETTER BET FOR TSTMS DURING THE
SHORT TERM PERIOD WILL BE FRIDAY. CURRENTLY THE FORECAST AREA IS IN
A SLIGHT RISK FOR SEVERE TSTMS FRIDAY...BUT ULTIMATELY IT MAY DEPEND
ON THE AMOUNT OF CLOUD COVER WHICH COULD IMPEDE DESTABILIZATION.
OTHERWISE...FAVORED A BLEND OF MAV/MET NUMBERS EACH PERIOD.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
AS OF 3 PM WEDNESDAY...IN A PATTERN MORE COMMONLY SEEN IN NOVEMBER
THAN MID-AUGUST...A HIGHLY ANOMALOUS 500MB TROUGH SPINS ACROSS THE
GREAT LAKES BEFORE ROTATING OFF TO THE NORTHEAST DURING THE EARLY
PART OF THE WEEK. AS THIS TROUGH SLOWLY SPINS AWAY...IT DRAGS A COLD
FRONT ACROSS THE AREA. GUIDANCE IN DECENT AGREEMENT ON TIMING OF
THIS FRONT...AND EXPECT FROPA TO OCCUR VERY EARLY SUNDAY. MOST
SIGNIFICANT WEATHER OF THE EXTENDED WILL OCCUR SATURDAY AS FRONT
PUSHES ACROSS THE AREA...DISPLACING THE WARM SECTOR AIRMASS. ATTM
SPC HAS NO PORTION OF OUR REGION OUTLOOKED IN DAY 4...BUT WOULD NOT
BE SURPRISED IF A SLIGHT RISK OR SEE TEXT IS INTRODUCED WITH LATER
UPDATES AS FRONT WORKS INTO A MODERATELY UNSTABLE AIRMASS WITH
DECENT NEARLY UNIDIRECTIONAL SHEAR AND HIGH PWATS.
ADDITIONALLY...GFS/EURO SHOW STRONG PVA ASSOCIATED WITH A VORT LOBE
ALONG THE FRONT AND DIFFLUENCE IN THE RIGHT ENTRANCE REGION TO A
90KT 300MB JET. ALL THESE TOGETHER SUGGEST SCATTERED TO WIDESPREAD
THUNDERSTORMS SATURDAY...WITH THE POTENTIAL FOR ISOLATED DAMAGING
WIND GUSTS. THE LIMITING FACTOR MAY BE INCREASED CLOUD COVER FROM
CONVECTIVE DEBRIS FRIDAY...BUT THIS IS STILL YET TO BE SEEN. WILL
KEEP INHERITED LIKELY POP SATURDAY...WANING TO SCHC BY SUNDAY
MORNING AS FRONT MOVES OFFSHORE. TEMPS SATURDAY WILL BE RIGHT AROUND
CLIMO...90/70.
DRIER AIR BEHIND THE FRONT COMBINED WITH SLIGHTLY INCREASED 500MB
HEIGHTS WILL CAUSE A SIGNIFICANT DECREASE IN TSTM CHANCES SUN-TUE.
STILL...WITH TEMPS AROUND 90 AND SLIGHTLY ENHANCED LAPSE RATES DUE
TO BROAD EAST-COAST TROUGHING...ANY DAY COULD FEATURE ISOLATED
DIURNAL CONVECTION. WILL KEEP POP BELOW MENTIONABLE SUN/MON BEFORE
MOISTURE RETURN INCREASES WITH RETURN OF BERMUDA HIGH TUE/WED. TEMPS
THROUGH THE WEEK WILL BE NEAR NORMAL FOR MID AUGUST.
&&
.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
AS OF 18Z...SOME LIGHT SHOWERS WILL PERSISTS FOR THE FIRST COUPLE OF
HOURS ALONG THE COAST. THEY SHOULD HAVE LITTLE AVIATION IMPACT. LOOK
FOR VFR CONDITIONS THROUGH THE AFTERNOON HOURS...WITH ISOLATED
SHOWERS POSSIBLE. LIGHT WINDS TONIGHT WITH SCATTERING SKIES. GIVEN
THOSE CONDITIONS...ALONG WITH GOOD LOW LEVEL MOISTURE...EXPECT IFR
FOG TO EMERGE AFTER 08Z. IT IS POSSIBLE IT COULD BECOME DENSE...BUT
WILL STAY WITH IFR AT THIS TIME. THURSDAY...MORNING FOG SHOULD MIX
OUT BY 13Z WITH VFR CONDITIONS EXPECTED. LIGHT NORTHWEST FLOW BEHIND
THE DEEP MOISTURE EXITING THE REGION.
EXTENDED OUTLOOK...CHANCE OF MORNING MVFR VSBYS IN BR WITH A CHANCE
OF SHOWERS AND THUNDERSTORMS EACH DAY.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 6:00 PM WEDNESDAY...NO CHANGES TO COASTAL WATERS FORECAST WITH
THE EVENING UPDATE.
SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 3 PM WEDNESDAY...LIGHT WESTERLY FLOW THURSDAY MORNING WILL
BACK TO A SOUTHERLY DIRECTION DURING THE DAY AND INCREASE INTO THE
10-15 KT RANGE. SOUTH TO SOUTHWEST FLOW WILL PREVAIL THURSDAY NIGHT
AND LINGER AROUND 15 KT FRIDAY. SPEEDS COULD REACH 15-20 KT FRIDAY
NIGHT AHEAD OF A COLD FRONT. THE SOUTH TO SOUTHWEST FETCH WILL ALLOW
SEAS TO BUILD TO EXERCISE CAUTION LEVELS DURING THE PERIOD...AND
WILL BE HIGHEST DURING FRIDAY NIGHT
LONG TERM /SATURDAY THROUGH MONDAY/...
AS OF 3 PM WEDNESDAY...SW FLOW THROUGH THE PERIOD...BUT WILL BE
STRONGEST SATURDAY AS COLD FRONT APPROACHES FROM THE WEST. AS THIS
FRONT WORKS TOWARDS THE COAST...PRESSURE GRADIENT TIGHTENS...AND
WINDS WILL BE AROUND 15 KTS SATURDAY. GRADIENT WILL EASE AS FRONT
MOVES TO THE WATERS AND DISSIPATES BY EARLY SUNDAY...BECOMING 10 KTS
OR LESS SUNDAY AND MONDAY...STILL FROM THE SW. A WEAK SE SWELL WILL
EXIST THROUGH THE EXTENDED...BUT SIGNIFICANT WAVE HEIGHTS WILL BE
DRIVEN ALMOST EXCLUSIVELY BY THE WIND. 3-5 FT SEAS SATURDAY WILL
DECREASE THROUGH SUNDAY...BECOMING 2-3 FT LATE SUNDAY AND MONDAY.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...15
SHORT TERM...SRP
LONG TERM...JDW
AVIATION...DL/HAWKINS
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
946 PM EDT THU AUG 9 2012
.SYNOPSIS...
STRONG COLD FRONT FOR AUGUST PASSES LATE FRIDAY. HIGH PRESSURE
BUILDS IN THIS WEEKEND WITH COOLER TEMPERATURES.
&&
.NEAR TERM /THROUGH FRIDAY/...
THE MID LEVEL 500 MB VORT MAX INDICATED BY RADAR STRUCTURE W OF PKB
AT 01Z. RAP MDL HAS THE AXIS PASSING THRU NRN CNTRL WV AND ACRS NRN
WV MTNS BY 05Z. SO RADAR COVERAGE INCREASING ACROSS CNTRL AND NRN
WV COUNTIES AFTER 01Z...SHOULD SEE A DECREASING TREND 04Z TO 06Z.
STILL HAVE INCREASING COVERAGE AGAIN IN MID OHIO VALLEY 09Z TO 12Z.
&&
.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY NIGHT/...
FRONTAL BOUNDARY WILL CROSS CWA FRI EVENING WITH SOME SHRA AND
PERHAPS A RUMBLE OF THUNDER...AS UPR TROF SETTLES IN OVER LWR GREAT
LAKES HEADING INTO WEEKEND. CARRIED LOW CHC POPS WITH THIS WITH
DRYING AFTER MIDNIGHT AS DRY SLOT WORKS IN FROM W. LOOKS LIKE UPR
COLD POOL ASSOCIATED CLDS WILL TEND TO STAY NORTH OF AREA AS COLUMN
DRIES OUT FOR WEEKEND WITH JUST SOME DIURNALLY DRIVE STRATOCU BOTH
DAYS. GUIDANCE HAS COME UP WITH MAXT NUMBERS FOR THIS WEEKEND. THIS
MAKES SENSE WITH CORE OF UPR COLD POOL NEVER REALLY MAKING IT THIS
FAR S WITH GENERALLY W TO WSW LLVL FLOW. THUS WILL BUMP UP NUMBERS A
TICK OR TWO MAINLY OUTSIDE OF THE MTNS. WILL GO WITH COOLER NUMBERS
FOR LOWS WITH GENERALLY LIGHT FLOW UNDER SFC HIGH...ALLOWING FOR
BETTER RADIATIONAL COOLING.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
EXTENDED WILL FEATURE UPR TROF REINFORCED EARLY NEXT WEEK AS
GENERALLY NW FLOW ALOFT CONTINUES. OVERALL ATMOS REMAINS ON DRY
SIDE...HOWEVER UPR DISTURBANCE MAY BRING A FEW MAINLY AFTN SHRA OR
STORMS TUE OR WED. UPR TROF LOOKS TO PULL OUT TOWARD WEEKS
END...REPLACED BY BUILDING HEIGHTS AND WARMER TEMPS.
&&
.AVIATION /02Z FRIDAY THROUGH TUESDAY/...
REMAINING OUT AHEAD OF THE SYNOPTIC SUPPORT AND COLD FRONT THROUGH
MOST OF THIS TAF FORECAST PERIOD. DO NOT EXPECT WEAK LOW PRESSURE
AND ASSOCIATED COLD FRONT TO PASS TRI STATE AROUND HTS UNTIL 21Z
FRIDAY TO 00Z SATURDAY.
OUT AHEAD OF THIS FEATURE...INDIVIDUAL BANDS OF CONVECTION WILL FORM
IN THE MID LEVEL SUPPORT. EXPECTING WEAKENING CONVECTION IN
SOUTHEAST OHIO DURING THE 03Z TO 06Z...WHILE CREEPING INTO
NORTHWESTERN WEST VIRGINIA.
MEANWHILE...SEPARATE AREA OF SHOWERS AND THUNDERSTORMS THURSDAY
EVENING MAY HOLD TOGETHER AS IT MOVES UP THE MOUNTAINOUS COUNTIES OF
WEST VIRGINIA FROM THE SSW.
FIGURING A LULL IN COVERAGE 04Z TO 08Z...WITH CONVECTION INCREASING
IN SOUTHEAST OHIO AGAIN BY THE PREDAWN HOURS.
OVERNIGHT...CEILINGS 2 TO 4 THSD FT BKN AND VSBY NEAR 3 MILES IN
CONVECTION OTHERWISE CEILINGS MOSTLY 6 TO 10 THSD FT BKN AND VSBY
AOA 5 MILES. SOME LOCAL VALLEY FOG POSSIBLE IN DEEPER VALLEYS OF
SOUTHERN WEST VIRGINIA AND IN THE MOUNTAINS MAY LOWER VSBY NEAR 3
MILES 06Z TO 12Z.
LOW LEVEL FLOW INCREASING DURING THE DAY ON FRIDAY. EXPECTING CU
AT 2 TO 4 THSD FT BKN AND VSBY OCCASIONALLY NEAR 3 MILES IN
SHOWERS AND THUNDERSTORMS.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 00Z SATURDAY...
FORECAST CONFIDENCE: LOW.
ALTERNATE SCENARIOS: TIMING THE INDIVIDUAL BANDS OF CONVECTION BY
THE PREDAWN HOURS INTO THE DAY ON FRIDAY COULD BE FASTER AND SHORTER
DURATIONS THAN INDICATED IN TAFS.
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 FRI 08/10/12
UTC 1HRLY 02 03 04 05 06 07 08 09 10 11 12 13
EDT 1HRLY 22 23 00 01 02 03 04 05 06 07 08 09
CRW CONSISTENCY H H H H H H H H H H H H
HTS CONSISTENCY H H H H H H H H H L H H
BKW CONSISTENCY H H H H H H H H H H H H
EKN CONSISTENCY H H H H H H H M M M M M
PKB CONSISTENCY H H H H H H H H H H H H
CKB CONSISTENCY H H H H H H H H H H H H
AFTER 00Z SATURDAY...
IFR CONDITIONS POSSIBLE UNDER HEAVIEST SHOWERS/TSRA FRIDAY.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...30/26
NEAR TERM...KTB
SHORT TERM...30
LONG TERM...30
AVIATION...KTB
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
818 PM EDT THU AUG 9 2012
.SYNOPSIS...
STRONG COLD FRONT FOR AUGUST PASSES LATE FRIDAY. HIGH PRESSURE
BUILDS IN THIS WEEKEND WITH COOLER TEMPERATURES.
&&
.NEAR TERM /THROUGH FRIDAY/...
AS EXPECTED...THE CONVECTION FORMED IN OHIO ALONG THE BOUNDARY AND
IS SLOWLY CREEPING TOWARD THE MID OHIO VALLEY AND THE OHIO RIVER.
YET...WE THOUGHT THE SOUTHERN RAIN WOULD SURVIVE INTO CENTRAL
WV...BUT WEAKENED CONSIDERABLY IN SOUTHERN WV. YET...EVEN WHEN WE
THOUGHT IT WAS FALLING APART...A NEW THUNDERSTORM FORMED NEAR OCEANA
IN WYOMING COUNTY AT SUNSET.
WAS MUCH SLOWER IN INCREASING POPS TONIGHT IN NORTH CENTRAL WV...FROM
CKB INTO THE MOUNTAINS AROUND EKN.
ONE VORT MAX ON THE RAP LIFTS NE THRU PKB AROUND 02Z INTO WRN PA BY
04Z. WILL TRY TO SPEED UP POPS INCREASING BEFORE DAWN IN SOUTHEAST
OHIO AND THE OHIO RIVER. BUT HAVE LOW CONFIDENCE ON TIMING THE
INITIAL BANDS ON FRIDAY.
&&
.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY NIGHT/...
FRONTAL BOUNDARY WILL CROSS CWA FRI EVENING WITH SOME SHRA AND
PERHAPS A RUMBLE OF THUNDER...AS UPR TROF SETTLES IN OVER LWR GREAT
LAKES HEADING INTO WEEKEND. CARRIED LOW CHC POPS WITH THIS WITH
DRYING AFTER MIDNIGHT AS DRY SLOT WORKS IN FROM W. LOOKS LIKE UPR
COLD POOL ASSOCIATED CLDS WILL TEND TO STAY NORTH OF AREA AS COLUMN
DRIES OUT FOR WEEKEND WITH JUST SOME DIURNALLY DRIVE STRATOCU BOTH
DAYS. GUIDANCE HAS COME UP WITH MAXT NUMBERS FOR THIS WEEKEND. THIS
MAKES SENSE WITH CORE OF UPR COLD POOL NEVER REALLY MAKING IT THIS
FAR S WITH GENERALLY W TO WSW LLVL FLOW. THUS WILL BUMP UP NUMBERS A
TICK OR TWO MAINLY OUTSIDE OF THE MTNS. WILL GO WITH COOLER NUMBERS
FOR LOWS WITH GENERALLY LIGHT FLOW UNDER SFC HIGH...ALLOWING FOR
BETTER RADIATIONAL COOLING.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
EXTENDED WILL FEATURE UPR TROF REINFORCED EARLY NEXT WEEK AS
GENERALLY NW FLOW ALOFT CONTINUES. OVERALL ATMOS REMAINS ON DRY
SIDE...HOWEVER UPR DISTURBANCE MAY BRING A FEW MAINLY AFTN SHRA OR
STORMS TUE OR WED. UPR TROF LOOKS TO PULL OUT TOWARD WEEKS
END...REPLACED BY BUILDING HEIGHTS AND WARMER TEMPS.
&&
.AVIATION /00Z FRIDAY THROUGH TUESDAY/...
REMAINING OUT AHEAD OF THE SYNOPTIC SUPPORT AND COLD FRONT THROUGH
MOST OF THIS TAF FORECAST PERIOD. DO NOT EXPECT WEAK LOW PRESSURE
AND ASSOCIATED COLD FRONT TO PASS TRI STATE AROUND HTS UNTIL 21Z
FRIDAY TO 00Z SATURDAY.
OUT AHEAD OF THIS FEATURE...INDIVIDUAL BANDS OF CONVECTION WILL FORM
IN THE MID LEVEL SUPPORT. EXPECTING WEAKENING CONVECTION IN
SOUTHEAST OHIO DURING THE 03Z TO 06Z...WHILE CREEPING INTO
NORTHWESTERN WEST VIRGINIA.
MEANWHILE...SEPARATE AREA OF SHOWERS AND THUNDERSTORMS THURSDAY
EVENING MAY HOLD TOGETHER AS IT MOVES UP THE MOUNTAINOUS COUNTIES OF
WEST VIRGINIA FROM THE SSW.
FIGURING A LULL IN COVERAGE 04Z TO 08Z...WITH CONVECTION INCREASING
IN SOUTHEAST OHIO AGAIN BY THE PREDAWN HOURS.
OVERNIGHT...CEILINGS 2 TO 4 THSD FT BKN AND VSBY NEAR 3 MILES IN
CONVECTION OTHERWISE CEILINGS MOSTLY 6 TO 10 THSD FT BKN AND VSBY
AOA 5 MILES. SOME LOCAL VALLEY FOG POSSIBLE IN DEEPER VALLEYS OF
SOUTHERN WEST VIRGINIA AND IN THE MOUNTAINS MAY LOWER VSBY NEAR 3
MILES 06Z TO 12Z.
LOW LEVEL FLOW INCREASING DURING THE DAY ON FRIDAY. EXPECTING CU
AT 2 TO 4 THSD FT BKN AND VSBY OCCASIONALLY NEAR 3 MILES IN
SHOWERS AND THUNDERSTORMS.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 00Z SATURDAY...
FORECAST CONFIDENCE: LOW.
ALTERNATE SCENARIOS: TIMING THE INDIVIDUAL BANDS OF CONVECTION BY
THE PREDAWN HOURS INTO THE DAY ON FRIDAY COULD BE FASTER AND SHORTER
DURATIONS THAN INDICATED IN TAFS.
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 FRI 08/10/12
UTC 1HRLY 00 01 02 03 04 05 06 07 08 09 10 11
EDT 1HRLY 20 21 22 23 00 01 02 03 04 05 06 07
CRW CONSISTENCY H H H H H H H H H H H H
HTS CONSISTENCY H H H H H H H H H H H L
BKW CONSISTENCY M H H H H H H H H H H H
EKN CONSISTENCY H H H H H H H H H M M M
PKB CONSISTENCY M H H H H H H H H H H H
CKB CONSISTENCY H H H H H H H H H H H H
AFTER 00Z SATURDAY...
IFR CONDITIONS POSSIBLE UNDER HEAVIEST SHOWERS/TSRA FRIDAY.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...30/26
NEAR TERM...KTB
SHORT TERM...30
LONG TERM...30
AVIATION...KTB
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
431 PM EDT WED AUG 8 2012
.SYNOPSIS...
A WEAK COLD FRONT WILL REMAIN NEARLY STATIONARY ALONG THE OHIO
RIVER TONIGHT INTO THURSDAY. A STRONGER COLD FRONT AHEAD OF AN
ENERGETIC UPPER LEVEL LOW WILL BRING A ROUND OF SHOWERS AND
THUNDERSTORMS TO THE OHIO VALLEY ON THURSDAY NIGHT AND FRIDAY.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
A WEAK COLD FRONT HAD DROPPED SOUTH INTO NORTHERN OHIO AND INDIANA
LATE THIS AFTERNOON. THIS AFTERNOON...WIDELY SCATTERED TO SCATTERED SHOWERS
AND THUNDERSTORMS HAD DEVELOPED ALONG AND AHEAD OF THE COLD FRONT
DUE TO WEAK LOW LEVEL FORCING AND HOT AFTERNOON TEMPERATURES. THIS
FRONT WILL CONTINUE TO DROP SOUTH TONIGHT AND BECOME NEARLY
STATIONARY NEAR THE OHIO RIVER. THE SHOWER AND THUNDERSTORM
ACTIVITY WILL DECREASE THROUGH THE LATE EVENING HOURS. ANOTHER
CHANCE OF SHOWERS/THUNDERSTORMS WILL OCCUR IN THE EARLY MORNING
HOURS WITH AN UPPER LEVEL SYSTEM. WITH HIGH INSTABILITY ACROSS
THE REGION THROUGH THIS EVENING...CAN NOT RULE OUT AN ISOLATED SEVERE
THUNDERSTORM. DAMAGING WINDS AND LARGE HAIL WOULD BE THE MAIN
THREATS.
THE LOWS TONIGHT WILL BE WARMER THAN WEDNESDAY NIGHT WITH LOWS IN
THE MID 60S TO AROUND 70.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH THURSDAY NIGHT/...
THE WEAK COLD FRONT WILL LAY OUT AS A BOUNDARY ON THURSDAY AND
ANOTHER MID LEVEL SHORTWAVE WILL INTERACT WITH IT. THIS WILL BRING
A BETTER CHANCE OF THUNDERSTORMS ACROSS THE FORECAST AREA. WILL
ALSO SEE A CHANCE OF SEVERE WEATHER WITH THE MAIN THREAT BEING DAMAGING
WINDS. LOW PRESSURE WILL RIDE NE ALONG THE BOUNDARY THURSDAY NIGHT
IN RESPONSE TO AN UPPER LOW STRENGTHENING OVER THE WESTERN GREAT
LAKES AND CROSSING THE NORTHERN OHIO VALLEY BY EARLY FRI. MODELS
HANDLE THE TRACK OF THE LOW A LITTLE DIFFERENTLY WHICH WILL IMPACT
WHERE GREATEST PRECIPITATION OCCURRS. THE BEST COVERAGE OF
SHOWERS/THUNDERSTORMS WILL BE LATE THURSDAY INTO FRIDAY AS THE LOW
APPROACHES AND MOVES THROUGH THE OHIO VALLEY REGION.
WITH AN INCREASE IN CLOUDS AND PRECIPITATION THURSDAY...THE HIGH
TEMEPRATURES WILL BE COOLER THAN TODAY. MOST AREAS WILL SEE HIGHS
IN THE 80S EXCEPT AROUND 90 IN THE FAR SE. THE LOWS THURSDAY NIGHT
WILL BE IN THE 60S.
&&
.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
CLOSED UPPER LOW PROGGED TO BE OVER LOWER MICHIGAN AT 12Z FRIDAY
WITH SURFACE LOW POSITIONED OVER LAKE ERIE. THIS SYSTEM WILL
GRADUALLY PUSH FURTHER NORTHEASTWARD INTO CANADA THROUGH THE FIRST
PART OF THE WEEKEND...LEAVING MAINLY DRY AND COOLER CONDITIONS IN
ITS WAKE. WENT ON THE COOL SIDE OF GUIDANCE FOR FRIDAY AS
CLOUDS... PRECIPITATION...AND NORTHERLY FLOW BEHIND A FRONTAL
BOUNDARY WILL KEEP TEMPERATURES DOWN. FORECASTED HIGHS FOR FRIDAY
RIGHT NOW ARE ABOUT 10 DEGREES BELOW NORMAL. BOTH THE 00Z AND 12Z
ECMWF RUNS HAVE BEEN A LITTLE QUICKER TO PUSH THE SYSTEM OUT OF
THE AREA THAN THE LATEST NAM/GFS...SO DECIDED TO KEEP JUST SLIGHT
POPS INTO SATURDAY FOR THE FAR NORTHEASTERN CWA.
EXPECT A GRADUAL CLEARING SATURDAY AFTERNOON INTO THE OVERNIGHT AS
THE LOW PUSHES AWAY. LOWS SATURDAY NIGHT WILL BE COOL AS HIGH
PRESSURE BUILDS INTO THE REGION. WINDS WILL BECOME MORE SOUTHERLY BY
SUNDAY THE HIGH DRIFTS EAST OF THE REGION. THIS WILL BE THE START OF
A WARMING TREND THAT WILL CONTINUE THROUGH THE FIRST PART OF NEXT
WEEK WITH TEMPERATURES BACK IN THE 80S.
ONLY OTHER FEATURES OF CONCERN FOR THE EXTENDED PERIOD WILL ARRIVE
MONDAY INTO MONDAY NIGHT AS THE GFS BRINGS A DECENT SHORTWAVE AND
SURFACE LOW THROUGH THE REGION. NEITHER FEATURE HAS BEEN QUITE AS
DEVELOPED IN THE PAST TWO ECMWF RUNS AND THUS THE ECMWF HAS BEEN
TRENDING DRY. WENT AHEAD AND INTRODUCED SLIGHT POPS FOR THIS PERIOD
AS THE PAST FEW GFS RUNS HAVE BEEN CONSISTENT AND THE FEATURES ARE
AT LEAST EVIDENT IN THE ECMWF...BUT CONFIDENCE IN PRECIP IS NOT VERY
HIGH AT THIS TIME.
&&
.AVIATION /20Z WEDNESDAY THROUGH MONDAY/...
CU FIELD IS TRYING TO FILL IN ACROSS THE AREA EARLY THIS AFTERNOON
AS WE CONTINUE TO WARM UP AND DESTABILIZE. ML CAPES ARE NOW INTO
THE 1500 TO 2000 J/KG RANGE ACROSS MUCH OF THE REGION. AS THE COLD
FRONT SAGS SLOWLY SOUTH ACROSS THE REGION THROUGH THIS EVENING...A
FEW THUNDERSTORMS MAY POP UP GIVEN THE INSTABILITY AND WEAK LOW
LEVEL FORCING. MEANWHILE...REMNANTS FROM EARLIER CONVECTION ARE
CONTINUING TO PROGRESS ACROSS ILLINOIS TOWARD WESTERN INDIANA. THE
LAST FEW RUNS OF THE RAP HAVE BEEN TRYING TO PIVOT A WEAKENING
LINE OF SHOWERS ASSOCIATED WITH THIS UP ACROSS AT LEAST OUR WESTERN
AREAS THROUGH EARLY EVENING. GIVEN THE UNCERTAINTY...THINK THE BEST
WAY TO COVER THE CHANCE RIGHT NOW IS JUST WITH A VCSH. ANOTHER
WEAK MID LEVEL SHORT WAVE WILL THEN PUSH TOWARD THE AREA LATE
TONIGHT INTO THURSDAY MORNING. EXPECT THE BEST CHANCE FOR ANY
PCPN ASSOCIATED WITH THIS TO BE ACROSS OUR NORTH AND WILL AGAIN
COVER WITH A VCSH. A BETTER CHANCE OF SHOWERS AND THUNDERSTORMS WILL
THEN DEVELOP OFF TO OUR WEST THROUGH THE AFTERNOON
HOURS...POSSIBLY AFFECTING CVG TOWARD THE END OF THEIR TAF
PERIOD.
.OUTLOOK...THUNDERSTORMS ARE POSSIBLE INTO FRIDAY.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...PARKER
NEAR TERM...PARKER
SHORT TERM...PARKER
LONG TERM...KURZ
AVIATION...JGL
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
154 PM EDT WED AUG 8 2012
.SYNOPSIS...
A WEAK COLD FRONT WILL CROSS THE REGION TODAY. THIS FRONT WILL
REMAIN NEARLY STATIONARY ALONG THE OHIO RIVER TONIGHT INTO
THURSDAY. A STRONGER COLD FRONT AHEAD OF AN ENERGETIC UPPER LEVEL
LOW WILL BRING A ROUND OF SHOWERS AND THUNDERSTORMS TO THE OHIO
VALLEY ON THURSDAY NIGHT AND FRIDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
LOOKS LIKE MAYBE A FEW AC UP ACROSS OUR NORTH BUT FOR THE MOST
PART...SKIES ARE MOSTLY CLEAR THIS MORNING. A WEAK COLD FRONT
CURRENTLY ACROSS FAR NORTHERN INDIANA AND OHIO...WILL SAG SOUTH
INTO OUR AREA THROUGH THIS AFTERNOON. AHEAD OF THE FRONT...WE
SHOULD SEE A DECENT WARM UP THROUGH THIS AFTERNOON. TEMPS ARE
CURRENTLY RUNNING SEVERAL DEGREES AHEAD OF YESTERDAY AND THE 12Z
ILN SOUNDING IS 19 DEGREES AT 850 MB...WHICH IS 3 DEGREES WARMER
THAN TUESDAY MORNING. AS A RESULT...EXPECT TEMPERATURES 4 TO MAYBE
EVEN 5 DEGREES WARMER THAN WHAT SAW YESTERDAY AFTERNOON...ESPECIALLY
ACROSS SOUTHERN PORTIONS OF OUR AREA WHERE BEST LOW LEVEL WAA
SHOULD EXIST AHEAD OF THE FRONT. WILL GENERALLY HAVE HIGHS IN THE
LOW TO MID 90S. CVG DID GET TO 95 DEGREES YESTERDAY...SO A FEW UPPER
90S ARE NOT OUT OF THE QUESTION ACROSS OUR SOUTHWEST. THE RECORD
FOR CVG IS 100 DEGREES AND CMH IS 96...SO WE MAY NOT BE TOO FAR
OFF FROM THOSE NUMBERS. MEANWHILE AS WE DESTABILIZE THROUGH THIS
AFTERNOON...TOUGH TO RULE OUT A FEW THUNDERSTORMS GIVEN WEAK LOW
LEVEL FORCING ALONG THE FRONT.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY NIGHT/...
THE WEAK COLD FRONT WILL LAY OUT AS A BOUNDARY ON THURSDAY AND
ANOTHER MID LEVEL SHORTWAVE WILL INTERACT WITH IT AND STAND A
BETTER CHANCE OF POPPING SOME THUNDERSTORMS OVER THE AREA. THE
BOUNDARY WILL SEE LOW PRESSURE RIDE NORTHEAST ALONG IT THURSDAY
NIGHT IN RESPONSE TO AN UPPER LOW STRENGTHENING OVER THE WESTERN
GREAT LAKES AND CROSSING THE NORTHERN OHIO VALLEY BY EARLY FRIDAY.
THE SHOWERS AND THUNDERSTORMS THAT DEVELOP THURSDAY NIGHT IN
RESPONSE TO THESE FEATURES WILL BECOME MORE AND MORE LIKELY AS
TIME PROGRESSES.
TEMPERATURES ON FRIDAY WILL BE MARKEDLY COOLER...UPPER 60S TO
LOWER 70S IN A COLD ADVECTION PATTERN AND NOTABLY WETTER IN THE
POST-FRONTAL WRAP AROUND MOISTURE. SIGNIFICANTLY COOLER AIR WILL
BE OVER THE REGION THIS WEEKEND AS A CUTOFF LOW PROVIDES FOR
CLOUDY SKIES AND A CONTINUED COLD PUSH ON NORTHERLY WINDS.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
FOR SATURDAY INTO SATURDAY NIGHT...A QUICKER UPR LVL LOW MOTION
TO THE NE WAS USED BUT MAY END UP BEING SLOWER THAN CURRENTLY
FORECAST DUE TO RECENT MODEL GUIDANCE. HAVE A CHANCE OF SHOWERS
DIMINISHING WEST TO EAST THROUGH THIS PERIOD ALONG WITH GRADUAL
CLEARING SATURDAY INTO SATURDAY NIGHT. TEMPERATURES ON SATURDAY
WILL BE CLOUD DEPENDENT AND HAVE GONE WITH HIGHS IN THE MID TO
UPPER 70S. LOWS SATURDAY NIGHT WILL BE COOL AS SURFACE HIGH
PRESSURE BUILDS INTO THE REGION.
FOR THE REMAINDER OF THE EXTENDED...SUNDAY THROUGH TUESDAY...THE
GREAT LAKES AND OHIO VALLEY AREA WILL BE UNDER A NORTHWEST FLOW
PATTERN ALOFT. THERE ARE INDICATIONS THAT A FEW WEAK DISTURBANCES
WILL RIPPLE SE WITHIN THIS FLOW...BRINGING A SMALL THREAT FOR PCPN.
GIVEN THAT THEY APPEAR WEAK ATTM AND TIMING IS DIFFICULT AT BEST AT
THIS JUNCTURE...HAVE MAINTAINED A DRY FORECAST ALONG WITH MODIFYING
TEMPERATURES AS HEIGHTS AND TEMPERATURES ALOFT RISE THROUGH THE
PERIOD.
&&
.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
CU FIELD IS TRYING TO FILL IN ACROSS THE AREA EARLY THIS AFTERNOON
AS WE CONTINUE TO WARM UP AND DESTABILIZE. ML CAPES ARE NOW INTO
THE 1500 TO 2000 J/KG RANGE ACROSS MUCH OF THE REGION. AS THE COLD
FRONT SAGS SLOWLY SOUTH ACROSS THE REGION THROUGH THIS EVENING...A
FEW THUNDERSTORMS MAY POP UP GIVEN THE INSTABILITY AND WEAK LOW
LEVEL FORCING. MEANWHILE...REMNANTS FROM EARLIER CONVECTION ARE
CONTINUING TO PROGRESS ACROSS ILLINOIS TOWARD WESTERN INDIANA. THE
LAST FEW RUNS OF THE RAP HAVE BEEN TRYING TO PIVOT A WEAKENING
LINE OF SHOWERS ASSOCIATED WITH THIS UP ACROSS AT LEAST OUR WESTERN
AREAS THROUGH EARLY EVENING. GIVEN THE UNCERTAINTY...THINK THE BEST
WAY TO COVER THE CHANCE RIGHT NOW IS JUST WITH A VCSH. ANOTHER
WEAK MID LEVEL SHORT WAVE WILL THEN PUSH TOWARD THE AREA LATE
TONIGHT INTO THURSDAY MORNING. EXPECT THE BEST CHANCE FOR ANY
PCPN ASSOCIATED WITH THIS TO BE ACROSS OUR NORTH AND WILL AGAIN
COVER WITH A VCSH. A BETTER CHANCE OF SHOWERS AND THUNDERSTORMS WILL
THEN DEVELOP OFF TO OUR WEST THROUGH THE AFTERNOON
HOURS...POSSIBLY AFFECTING CVG TOWARD THE END OF THEIR TAF
PERIOD.
.OUTLOOK...THUNDERSTORMS ARE POSSIBLE INTO FRIDAY.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...FRANKS
NEAR TERM...JGL
SHORT TERM...FRANKS
LONG TERM...HICKMAN
AVIATION...JGL
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
120 PM EDT WED AUG 8 2012
.SYNOPSIS...
A WEAK COLD FRONT JUST NORTH OF LAKE ERIE WILL MOVE SOUTHEAST ACROSS
THE LOCAL AREA TODAY AND THEN STALL NEAR THE OHIO RIVER. LOW
PRESSURE WILL MOVE UP THE OHIO VALLEY THURSDAY AND FRIDAY. HIGH PRESSURE
WILL SLOWLY BUILD OVER THE REGION FROM THE WEST OVER THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
COLD FRONT FROM JUST NORTH OF BUF TO JUST SOUTH OF TOL. FORECAST
LOOKS REASONABLE. MADE MINOR ADJUSTMENTS TO THE TIMING OF THE
CLOUD COVER FOR UPDATE.
PREVIOUS...THE COLD FRONT IS ON TRACK TO MOVE SE ACROSS THE AREA
TODAY. SOME SHOWERS AND EVEN SOME LIGHTNING OCCURRED EARLIER IN
THE NIGHT ALONG THE FRONT ACROSS LOWER MICHIGAN. LATEST HRRR AND
CONVECTIVE SREF CONTINUE TO SUGGEST THAT ISOLATED TO SCATTERED
SHOWERS AND STORMS WILL DEVELOP ALONG THE FRONT LATER TODAY. BEST
CHANCES FOR THIS WILL BE IN THE EAST THIS AFTERNOON. HAVE GONE
WITH A 20 TO 30 POP MOST AREAS. CLOUDS WILL COME AND GO TODAY BUT
BY LATE AFTERNOON SKIES SHOULD BE MAINLY PARTLY CLOUDY. HIGH TEMPS
WILL BE A DEGREE OR TWO COOLER THAN TUESDAY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY NIGHT/...
ACTIVE WEATHER IS EXPECTED DURING THE PERIOD AS AN UPPER LOW GETS
SET UP OVER THE EASTERN CONUS. THE MODELS NOW ARE FAIRLY SIMILAR
WITH THE MAIN FEATURES. LOW PRESSURE IS EXPECTED TO MOVE UP THE
OHIO VALLEY TONIGHT AND FRIDAY WITH THE LOW EVENTUALLY CROSSING WESTERN
PA. MODELS SHOWING GOOD ISENTROPIC LIFT WITH PWAT VALUES
EVENTUALLY REACHING 1.75 INCHES. INSTABILITY WILL INCREASE TONIGHT
AND THURSDAY AS DEWPOINTS SURGE INTO THE UPPER 60S. A FEW STRONG
TO SEVERE STORMS ARE LIKELY LATE THURSDAY AS THE LOW PASSES. SHEAR
WILL BE ENHANCED ALONG THE FRONT STRETCHING NE FROM THE LOW. THAT
IS LIKELY WHERE ANY SEVERE WEATHER WILL OCCUR. WRAP AROUND
MOISTURE BEHIND THE LOW WILL KEEP SHOWERS GOING THROUGH MIDDAY
SATURDAY ALL AREAS AND IN THE EAST ON SATURDAY NIGHT. 850 MB TEMPS
DIP TO PLUS 8 OR 10 SATURDAY DEPENDING ON WHICH MODEL YOU BELIEVE.
EITHER WAY COLD AIR ADVECTION CLOUDS AND SHOWERS WILL BE LIKELY TO
THE EAST OF KCLE. EXPECT MUCH OF THE AREA TO SEE AN INCH OR MORE
OR RAIN THURSDAY THROUGH FRIDAY. TEMPS DURING THE PERIOD WILL BE
BELOW NORMAL FOR A CHANGE.
&&
.LONG TERM /SUNDAY THROUGH TUESDAY/...
MODELS CONTINUING TO HANDLE STRONG UPPER TROUGH OVER THE AREA WELL
WITH GFS AND ECMWF MOVING IT OFF TO THE EAST ON SUNDAY WITH SFC HIGH
PRESSURE BUILDING INTO THE AREA. GOING INTO EARLY NEXT WEEK MADE
LITTLE CHANGES OVERALL TO THE FORECAST WITH 00Z ECMWF SHOWING BROAD
UPPER TROUGH MOVING ACROSS THE AREA WHILE GFS ALSO BRINGING UPPER
TROUGH OVER THE AREA BUT A BIT STRONGER WITH SFC LOW PRESSURE
DEVELOPING OVER THE MID MISSISSIPPI VALLEY. FOR NOW WILL CONTINUE TO
LEAN TOWARD THE ECMWF WITH MAINLY DRY CONDITIONS...BUT HAVE CONTINUE
WITH MORE CLOUDINESS ACROSS THE AREA DURING THIS TIME. WITH NO
STRONG TEMP ADVECTION MODERATED TEMPS FOR SUNDAY WITH THE TROUGH
DEPARTING BUT OTHERWISE KEPT THEM NEAR NORMAL FOR EARLY NEXT WEEK.
&&
.AVIATION /18Z WEDNESDAY THROUGH SUNDAY/...
A WEAK COLD FRONT WILL BECOME STATIONARY OVER THE CENTRAL PORTION
OF OHIO THIS EVENING. THIS BOUNDARY MAY CAUSE ENOUGH LOW LEVEL
CONVERGENCE TO CAUSE A COUPLE THUNDERSTORMS TO DEVELOP OVER NE
OHIO INTO NW PA. ONLY HAVE MENTIONED VICINITY THUNDER FOR THE
KYNG TAF AT THIS TIME. HOWEVER WILL WATCH INLAND LOCATIONS FURTHER
WEST THROUGH THE AFTERNOON.
UNCERTAINTY AS WE APPROACH SUNRISE IS THE AMOUNT OF MVFR FOG THAT
CAN DEVELOP WITH THE OVERALL INCREASE IN LIFT AS THE UPPER LEVEL
TROUGH ARRIVES. AT THIS POINT DID NOT INTRODUCE ANY INTO THE TAF
SITES BUT IF IT CAN OCCUR IT MAY BE ACROSS THE WESTERN TAF SITES.
BELIEVE THERE WILL ALSO BE SOME SHOWERS THAT DRIFT INTO THE WEST
ABOUT THE SAME TIME AS THE MVFR VISIBILITIES. SO FAR HAVE ONLY
INTRODUCED A VICINITY SHOWER WITH UNCERTAINTY ON HOW FAST IT WILL
MOVE INTO NW OHIO. THERE WILL EVENTUALLY BE A THREAT OF THUNDERSTORMS
AS WE HEAT THE SURFACE INTO THE EARLY AFTERNOON.
.OUTLOOK...PERIODS OF NON VFR POSSIBLE THURSDAY AND FRIDAY. NON
VFR POSSIBLE SATURDAY ACROSS NE OHIO INTO NW PA.
&&
.MARINE...
A WEAK COLD FRONT WILL MOVE ACROSS THE LAKE TODAY BUT SHOULD CAUSE
ANY SIGNIFICANT WEATHER OTHER THAN THE WIND SHIFT FROM SOUTHWEST TO
NORTH TONIGHT. THE SIGNIFICANT WEATHER ISSUE FOR THE LAKE WILL BEGIN
THURSDAY AS A STRONG UPPER TROUGH MOVES TOWARD THE LAKE AND SFC LOW
PRESSURE INTENSIFIES OVER THE OHIO VALLEY...THEN MOVES TO THE
NORTHEAST FRIDAY. NORTHEAST FLOW WILL INCREASE THROUGH THURSDAY WITH
WINDS RANGING 20 KNOTS OR GREATER BY THURSDAY NIGHT AND CONTINUING
THROUGH FRIDAY NIGHT. WINDS WILL SLOWLY DIMINISH THROUGH SATURDAY.
HIGH PRESSURE WILL BUILD OVER THE LAKE ON SUNDAY. SMALL CRAFT
ADVISORY CONDITIONS APPEAR LIKELY BEGINNING THURSDAY NIGHT AND
CONTINUING THROUGH AT LEAST SATURDAY MORNING.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...KUBINA
NEAR TERM...DJB/KUBINA
SHORT TERM...KUBINA
LONG TERM...ABE
AVIATION...MULLEN
MARINE...ABE
AREA FORECAST DISCUSSION...UPDATED
NWS CLEVELAND OH
909 AM EDT WED AUG 8 2012
.SYNOPSIS...
A WEAK COLD FRONT JUST NORTH OF LAKE ERIE WILL MOVE SOUTHEAST ACROSS
THE LOCAL AREA TODAY AND THEN STALL NEAR THE OHIO RIVER. LOW
PRESSURE WILL MOVE UP THE OHIO VALLEY THURSDAY AND FRIDAY. HIGH PRESSURE
WILL SLOWLY BUILD OVER THE REGION FROM THE WEST OVER THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
COLD FRONT FROM JUST NORTH OF BUF TO JUST SOUTH OF TOL. FORECAST
LOOKS REASONABLE. MADE MINOR ADJUSTMENTS TO THE TIMING OF THE
CLOUD COVER FOR UPDATE.
PREVIOUS...THE COLD FRONT IS ON TRACK TO MOVE SE ACROSS THE AREA
TODAY. SOME SHOWERS AND EVEN SOME LIGHTNING OCCURRED EARLIER IN
THE NIGHT ALONG THE FRONT ACROSS LOWER MICHIGAN. LATEST HRRR AND
CONVECTIVE SREF CONTINUE TO SUGGEST THAT ISOLATED TO SCATTERED
SHOWERS AND STORMS WILL DEVELOP ALONG THE FRONT LATER TODAY. BEST
CHANCES FOR THIS WILL BE IN THE EAST THIS AFTERNOON. HAVE GONE
WITH A 20 TO 30 POP MOST AREAS. CLOUDS WILL COME AND GO TODAY BUT
BY LATE AFTERNOON SKIES SHOULD BE MAINLY PARTLY CLOUDY. HIGH TEMPS
WILL BE A DEGREE OR TWO COOLER THAN TUESDAY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY NIGHT/...
ACTIVE WEATHER IS EXPECTED DURING THE PERIOD AS AN UPPER LOW GETS
SET UP OVER THE EASTERN CONUS. THE MODELS NOW ARE FAIRLY SIMILAR
WITH THE MAIN FEATURES. LOW PRESSURE IS EXPECTED TO MOVE UP THE
OHIO VALLEY TONIGHT AND FRIDAY WITH THE LOW EVENTUALLY CROSSING WESTERN
PA. MODELS SHOWING GOOD ISENTROPIC LIFT WITH PWAT VALUES
EVENTUALLY REACHING 1.75 INCHES. INSTABILITY WILL INCREASE TONIGHT
AND THURSDAY AS DEWPOINTS SURGE INTO THE UPPER 60S. A FEW STRONG
TO SEVERE STORMS ARE LIKELY LATE THURSDAY AS THE LOW PASSES. SHEAR
WILL BE ENHANCED ALONG THE FRONT STRETCHING NE FROM THE LOW. THAT
IS LIKELY WHERE ANY SEVERE WEATHER WILL OCCUR. WRAP AROUND
MOISTURE BEHIND THE LOW WILL KEEP SHOWERS GOING THROUGH MIDDAY
SATURDAY ALL AREAS AND IN THE EAST ON SATURDAY NIGHT. 850 MB TEMPS
DIP TO PLUS 8 OR 10 SATURDAY DEPENDING ON WHICH MODEL YOU BELIEVE.
EITHER WAY COLD AIR ADVECTION CLOUDS AND SHOWERS WILL BE LIKELY TO
THE EAST OF KCLE. EXPECT MUCH OF THE AREA TO SEE AN INCH OR MORE
OR RAIN THURSDAY THROUGH FRIDAY. TEMPS DURING THE PERIOD WILL BE
BELOW NORMAL FOR A CHANGE.
&&
.LONG TERM /SUNDAY THROUGH TUESDAY/...
MODELS CONTINUING TO HANDLE STRONG UPPER TROUGH OVER THE AREA WELL
WITH GFS AND ECMWF MOVING IT OFF TO THE EAST ON SUNDAY WITH SFC HIGH
PRESSURE BUILDING INTO THE AREA. GOING INTO EARLY NEXT WEEK MADE
LITTLE CHANGES OVERALL TO THE FORECAST WITH 00Z ECMWF SHOWING BROAD
UPPER TROUGH MOVING ACROSS THE AREA WHILE GFS ALSO BRINGING UPPER
TROUGH OVER THE AREA BUT A BIT STRONGER WITH SFC LOW PRESSURE
DEVELOPING OVER THE MID MISSISSIPPI VALLEY. FOR NOW WILL CONTINUE TO
LEAN TOWARD THE ECMWF WITH MAINLY DRY CONDITIONS...BUT HAVE CONTINUE
WITH MORE CLOUDINESS ACROSS THE AREA DURING THIS TIME. WITH NO
STRONG TEMP ADVECTION MODERATED TEMPS FOR SUNDAY WITH THE TROUGH
DEPARTING BUT OTHERWISE KEPT THEM NEAR NORMAL FOR EARLY NEXT WEEK.
&&
.AVIATION /13Z WEDNESDAY THROUGH SUNDAY/...
A WEAK COLD FRONT FROM LAKE ERIE ACROSS SRN MI WILL CONTINUE
MOVING SOUTH OVER NRN OH TODAY. SATELLITE SHOWING SOME CLOUDS
ALONG THE FRONT SO WENT WITH SCT-BKN 060-080 ACROSS SITES. MODELS
SHOWING THE POSSIBILITY OF SOME SHRA DEVELOPING ALONG THE FRONT
LATER THIS MORNING AND INTO THE AFTERNOON...BUT FOR LOCATIONS SUCH
AS TOL-CLE THINKING THAT ANY DEVELOPMENT WOULD OCCUR SOUTH OF
THOSE SITES. OVERALL GIVEN LOW PROBABILITIES DID MENTION SOME VCSH
AT SEVERAL SITES INCLUDING FDY-MFD-CAK-YNG. TOO LOW CONF AT ERI
TO INCLUDE VCSH. ALSO...GIVEN SUCH ISOLATED PROBABILITIES WILL
HOLD OFF ON THUNDER AT SITES. SOUTHWEST WINDS SHIFTING W THEN
NORTHERLY THROUGH TODAY WITH FROPA.
HIGH CLOUDS WILL QUICKLY BUILD IN FROM THE WEST LATE TODAY AND
THROUGH TONIGHT WITH NEXT WEATHER SYSTEM. CIGS LOWER TOWARD 10K FT
LATER TONIGHT WITH MAINLY NE FLOW DEVELOPING. POSSIBLE MVFR VIS
DEVELOPING BUT LATE IN PERIOD SO WILL LET NEXT SHIFT EVALUATE
PROBABILITY OF THAT.
.OUTLOOK...PERIODS OF NON VFR POSSIBLE THURSDAY AND FRIDAY ACROSS
ALL SITES. NON VFR POSSIBLE SATURDAY ACROSS EASTERN SITES.
&&
.MARINE...
A WEAK COLD FRONT WILL MOVE ACROSS THE LAKE TODAY BUT SHOULD CAUSE
ANY SIGNIFICANT WEATHER OTHER THAN THE WIND SHIFT FROM SOUTHWEST TO
NORTH TONIGHT. THE SIGNIFICANT WEATHER ISSUE FOR THE LAKE WILL BEGIN
THURSDAY AS A STRONG UPPER TROUGH MOVES TOWARD THE LAKE AND SFC LOW
PRESSURE INTENSIFIES OVER THE OHIO VALLEY...THEN MOVES TO THE
NORTHEAST FRIDAY. NORTHEAST FLOW WILL INCREASE THROUGH THURSDAY WITH
WINDS RANGING 20 KNOTS OR GREATER BY THURSDAY NIGHT AND CONTINUING
THROUGH FRIDAY NIGHT. WINDS WILL SLOWLY DIMINISH THROUGH SATURDAY.
HIGH PRESSURE WILL BUILD OVER THE LAKE ON SUNDAY. SMALL CRAFT
ADVISORY CONDITIONS APPEAR LIKELY BEGINNING THURSDAY NIGHT AND
CONTINUING THROUGH AT LEAST SATURDAY MORNING.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...KUBINA
NEAR TERM...DJB/KUBINA
SHORT TERM...KUBINA
LONG TERM...ABE
AVIATION...ABE
MARINE...ABE
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
729 AM EDT WED AUG 8 2012
.SYNOPSIS...
A WEAK COLD FRONT JUST NORTH OF LAKE ERIE WILL MOVE SOUTHEAST ACROSS
THE LOCAL AREA TODAY AND THEN STALL NEAR THE OHIO RIVER. LOW
PRESSURE WILL MOVE UP THE OHIO VALLEY THURSDAY AND FRIDAY. HIGH PRESSURE
WILL SLOWLY BUILD OVER THE REGION FROM THE WEST OVER THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
UPDATE ALREADY OUT. THE LATEST HRRR NOW SHOWING SCATTERED STORMS
DEVELOPING ALONG THE COLD FRONT THIS AFTERNOON. HAVE RAISED PRECIP
CHANCES SLIGHTLY OVER THE SE 1/3 OF THE AREA. MINOR ADJUSTMENTS TO
THE SKY COVER AS WELL.
PREVIOUS...THE COLD FRONT IS ON TRACK TO MOVE SE ACROSS THE AREA
TODAY. SOME SHOWERS AND EVEN SOME LIGHTNING OCCURRED EARLIER IN
THE NIGHT ALONG THE FRONT ACROSS LOWER MICHIGAN. LATEST HRRR AND
CONVECTIVE SREF CONTINUE TO SUGGEST THAT ISOLATED TO SCATTERED
SHOWERS AND STORMS WILL DEVELOP ALONG THE FRONT LATER TODAY. BEST
CHANCES FOR THIS WILL BE IN THE EAST THIS AFTERNOON. HAVE GONE
WITH A 20 TO 30 POP MOST AREAS. CLOUDS WILL COME AND GO TODAY BUT
BY LATE AFTERNOON SKIES SHOULD BE MAINLY PARTLY CLOUDY. HIGH TEMPS
WILL BE A DEGREE OR TWO COOLER THAN TUESDAY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY NIGHT/...
ACTIVE WEATHER IS EXPECTED DURING THE PERIOD AS AN UPPER LOW GETS
SET UP OVER THE EASTERN CONUS. THE MODELS NOW ARE FAIRLY SIMILAR
WITH THE MAIN FEATURES. LOW PRESSURE IS EXPECTED TO MOVE UP THE
OHIO VALLEY TONIGHT AND FRIDAY WITH THE LOW EVENTUALLY CROSSING WESTERN
PA. MODELS SHOWING GOOD ISENTROPIC LIFT WITH PWAT VALUES
EVENTUALLY REACHING 1.75 INCHES. INSTABILITY WILL INCREASE TONIGHT
AND THURSDAY AS DEWPOINTS SURGE INTO THE UPPER 60S. A FEW STRONG
TO SEVERE STORMS ARE LIKELY LATE THURSDAY AS THE LOW PASSES. SHEAR
WILL BE ENHANCED ALONG THE FRONT STRETCHING NE FROM THE LOW. THAT
IS LIKELY WHERE ANY SEVERE WEATHER WILL OCCUR. WRAP AROUND
MOISTURE BEHIND THE LOW WILL KEEP SHOWERS GOING THROUGH MIDDAY
SATURDAY ALL AREAS AND IN THE EAST ON SATURDAY NIGHT. 850 MB TEMPS
DIP TO PLUS 8 OR 10 SATURDAY DEPENDING ON WHICH MODEL YOU BELIEVE.
EITHER WAY COLD AIR ADVECTION CLOUDS AND SHOWERS WILL BE LIKELY TO
THE EAST OF KCLE. EXPECT MUCH OF THE AREA TO SEE AN INCH OR MORE
OR RAIN THURSDAY THROUGH FRIDAY. TEMPS DURING THE PERIOD WILL BE
BELOW NORMAL FOR A CHANGE.
&&
.LONG TERM /SUNDAY THROUGH TUESDAY/...
MODELS CONTINUING TO HANDLE STRONG UPPER TROUGH OVER THE AREA WELL
WITH GFS AND ECMWF MOVING IT OFF TO THE EAST ON SUNDAY WITH SFC HIGH
PRESSURE BUILDING INTO THE AREA. GOING INTO EARLY NEXT WEEK MADE
LITTLE CHANGES OVERALL TO THE FORECAST WITH 00Z ECMWF SHOWING BROAD
UPPER TROUGH MOVING ACROSS THE AREA WHILE GFS ALSO BRINGING UPPER
TROUGH OVER THE AREA BUT A BIT STRONGER WITH SFC LOW PRESSURE
DEVELOPING OVER THE MID MISSISSIPPI VALLEY. FOR NOW WILL CONTINUE TO
LEAN TOWARD THE ECMWF WITH MAINLY DRY CONDITIONS...BUT HAVE CONTINUE
WITH MORE CLOUDINESS ACROSS THE AREA DURING THIS TIME. WITH NO
STRONG TEMP ADVECTION MODERATED TEMPS FOR SUNDAY WITH THE TROUGH
DEPARTING BUT OTHERWISE KEPT THEM NEAR NORMAL FOR EARLY NEXT WEEK.
&&
.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
A WEAK COLD FRONT FROM LAKE ERIE ACROSS SRN MI WILL CONTINUE
MOVING SOUTH OVER NRN OH TODAY. SATELLITE SHOWING SOME CLOUDS
ALONG THE FRONT SO WENT WITH SCT-BKN 060-080 ACROSS SITES. MODELS
SHOWING THE POSSIBILITY OF SOME SHRA DEVELOPING ALONG THE FRONT
LATER THIS MORNING AND INTO THE AFTERNOON...BUT FOR LOCATIONS SUCH
AS TOL-CLE THINKING THAT ANY DEVELOPMENT WOULD OCCUR SOUTH OF
THOSE SITES. OVERALL GIVEN LOW PROBABILITIES DID MENTION SOME VCSH
AT SEVERAL SITES INCLUDING FDY-MFD-CAK-YNG. TOO LOW CONF AT ERI
TO INCLUDE VCSH. ALSO...GIVEN SUCH ISOLATED PROBABILITIES WILL
HOLD OFF ON THUNDER AT SITES. SOUTHWEST WINDS SHIFTING W THEN
NORTHERLY THROUGH TODAY WITH FROPA.
HIGH CLOUDS WILL QUICKLY BUILD IN FROM THE WEST LATE TODAY AND
THROUGH TONIGHT WITH NEXT WEATHER SYSTEM. CIGS LOWER TOWARD 10K FT
LATER TONIGHT WITH MAINLY NE FLOW DEVELOPING. POSSIBLE MVFR VIS
DEVELOPING BUT LATE IN PERIOD SO WILL LET NEXT SHIFT EVALUATE
PROBABILITY OF THAT.
.OUTLOOK...PERIODS OF NON VFR POSSIBLE THURSDAY AND FRIDAY ACROSS
ALL SITES. NON VFR POSSIBLE SATURDAY ACROSS EASTERN SITES.
&&
.MARINE...
A WEAK COLD FRONT WILL MOVE ACROSS THE LAKE TODAY BUT SHOULD CAUSE
ANY SIGNIFICANT WEATHER OTHER THAN THE WIND SHIFT FROM SOUTHWEST TO
NORTH TONIGHT. THE SIGNIFICANT WEATHER ISSUE FOR THE LAKE WILL BEGIN
THURSDAY AS A STRONG UPPER TROUGH MOVES TOWARD THE LAKE AND SFC LOW
PRESSURE INTENSIFIES OVER THE OHIO VALLEY...THEN MOVES TO THE
NORTHEAST FRIDAY. NORTHEAST FLOW WILL INCREASE THROUGH THURSDAY WITH
WINDS RANGING 20 KNOTS OR GREATER BY THURSDAY NIGHT AND CONTINUING
THROUGH FRIDAY NIGHT. WINDS WILL SLOWLY DIMINISH THROUGH SATURDAY.
HIGH PRESSURE WILL BUILD OVER THE LAKE ON SUNDAY. SMALL CRAFT
ADVISORY CONDITIONS APPEAR LIKELY BEGINNING THURSDAY NIGHT AND
CONTINUING THROUGH AT LEAST SATURDAY MORNING.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...KUBINA
NEAR TERM...KUBINA
SHORT TERM...KUBINA
LONG TERM...ABE
AVIATION...ABE
MARINE...ABE
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
627 AM EDT WED AUG 8 2012
.SYNOPSIS...
A WEAK COLD FRONT JUST NORTH OF LAKE ERIE WILL MOVE SOUTHEAST ACROSS
THE LOCAL AREA TODAY AND THEN STALL NEAR THE OHIO RIVER. LOW
PRESSURE WILL MOVE UP THE OHIO VALLEY THURSDAY AND FRIDAY. HIGH PRESSURE
WILL SLOWLY BUILD OVER THE REGION FROM THE WEST OVER THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
UPDATE ALREADY OUT. THE LATEST HRRR NOW SHOWING SCATTERED STORMS
DEVELOPING ALONG THE COLD FRONT THIS AFTERNOON. HAVE RAISED PRECIP
CHANCES SLIGHTLY OVER THE SE 1/3 OF THE AREA. MINOR ADJUSTMENTS TO
THE SKY COVER AS WELL.
PREVIOUS...THE COLD FRONT IS ON TRACK TO MOVE SE ACROSS THE AREA
TODAY. SOME SHOWERS AND EVEN SOME LIGHTNING OCCURRED EARLIER IN
THE NIGHT ALONG THE FRONT ACROSS LOWER MICHIGAN. LATEST HRRR AND
CONVECTIVE SREF CONTINUE TO SUGGEST THAT ISOLATED TO SCATTERED
SHOWERS AND STORMS WILL DEVELOP ALONG THE FRONT LATER TODAY. BEST
CHANCES FOR THIS WILL BE IN THE EAST THIS AFTERNOON. HAVE GONE
WITH A 20 TO 30 POP MOST AREAS. CLOUDS WILL COME AND GO TODAY BUT
BY LATE AFTERNOON SKIES SHOULD BE MAINLY PARTLY CLOUDY. HIGH TEMPS
WILL BE A DEGREE OR TWO COOLER THAN TUESDAY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY NIGHT/...
ACTIVE WEATHER IS EXPECTED DURING THE PERIOD AS AN UPPER LOW GETS
SET UP OVER THE EASTERN CONUS. THE MODELS NOW ARE FAIRLY SIMILAR
WITH THE MAIN FEATURES. LOW PRESSURE IS EXPECTED TO MOVE UP THE
OHIO VALLEY TONIGHT AND FRIDAY WITH THE LOW EVENTUALLY CROSSING WESTERN
PA. MODELS SHOWING GOOD ISENTROPIC LIFT WITH PWAT VALUES
EVENTUALLY REACHING 1.75 INCHES. INSTABILITY WILL INCREASE TONIGHT
AND THURSDAY AS DEWPOINTS SURGE INTO THE UPPER 60S. A FEW STRONG
TO SEVERE STORMS ARE LIKELY LATE THURSDAY AS THE LOW PASSES. SHEAR
WILL BE ENHANCED ALONG THE FRONT STRETCHING NE FROM THE LOW. THAT
IS LIKELY WHERE ANY SEVERE WEATHER WILL OCCUR. WRAP AROUND
MOISTURE BEHIND THE LOW WILL KEEP SHOWERS GOING THROUGH MIDDAY
SATURDAY ALL AREAS AND IN THE EAST ON SATURDAY NIGHT. 850 MB TEMPS
DIP TO PLUS 8 OR 10 SATURDAY DEPENDING ON WHICH MODEL YOU BELIEVE.
EITHER WAY COLD AIR ADVECTION CLOUDS AND SHOWERS WILL BE LIKELY TO
THE EAST OF KCLE. EXPECT MUCH OF THE AREA TO SEE AN INCH OR MORE
OR RAIN THURSDAY THROUGH FRIDAY. TEMPS DURING THE PERIOD WILL BE
BELOW NORMAL FOR A CHANGE.
&&
.LONG TERM /SUNDAY THROUGH TUESDAY/...
MODELS CONTINUING TO HANDLE STRONG UPPER TROUGH OVER THE AREA WELL
WITH GFS AND ECMWF MOVING IT OFF TO THE EAST ON SUNDAY WITH SFC HIGH
PRESSURE BUILDING INTO THE AREA. GOING INTO EARLY NEXT WEEK MADE
LITTLE CHANGES OVERALL TO THE FORECAST WITH 00Z ECMWF SHOWING BROAD
UPPER TROUGH MOVING ACROSS THE AREA WHILE GFS ALSO BRINGING UPPER
TROUGH OVER THE AREA BUT A BIT STRONGER WITH SFC LOW PRESSURE
DEVELOPING OVER THE MID MISSISSIPPI VALLEY. FOR NOW WILL CONTINUE TO
LEAN TOWARD THE ECMWF WITH MAINLY DRY CONDITIONS...BUT HAVE CONTINUE
WITH MORE CLOUDINESS ACROSS THE AREA DURING THIS TIME. WITH NO
STRONG TEMP ADVECTION MODERATED TEMPS FOR SUNDAY WITH THE TROUGH
DEPARTING BUT OTHERWISE KEPT THEM NEAR NORMAL FOR EARLY NEXT WEEK.
&&
.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
A WEAK COLD FRONT N OF LAKE ERI ACROSS SRN MI WILL CONTINUE TO
SLOWLY MOVE SOUTH ACROSS SITES THROUGH TODAY. RADAR SHOWING ONE
ISOL SHRA MOVING INTO NW OH SO WILL HAVE TO WATCH TOL...BUT NOT
THINKING MUCH FOR IMPACT. OTHERWISE EXPECTING SOME CLOUDS TO
DEVELOP LATER THIS MORNING AND AFTN ACROSS NRN OH AHEAD OF THE
FRONT. THERE MAY BE SOME ISOL SHRA WITH IT BUT NOT CONFIDENT ON
OCCURRENCE OR TIMING AT ANY PARTICULAR SITES. AT THIS TIME WOULD
THINK MFD-CAK-YNG WOULD HAVE BEST CHANCE FOR SHRA THIS AFTN. SOUTH
WINDS WILL GRADUALLY TURN NORTH AFTER FROPA THROUGH TODAY.
.OUTLOOK...PERIODS OF NON VFR POSSIBLE THURSDAY AND FRIDAY ACROSS
ALL SITES. NON VFR POSSIBLE SATURDAY ACROSS EASTERN SITES.
&&
.MARINE...
A WEAK COLD FRONT WILL MOVE ACROSS THE LAKE TODAY BUT SHOULD CAUSE
ANY SIGNIFICANT WEATHER OTHER THAN THE WIND SHIFT FROM SOUTHWEST TO
NORTH TONIGHT. THE SIGNIFICANT WEATHER ISSUE FOR THE LAKE WILL BEGIN
THURSDAY AS A STRONG UPPER TROUGH MOVES TOWARD THE LAKE AND SFC LOW
PRESSURE INTENSIFIES OVER THE OHIO VALLEY...THEN MOVES TO THE
NORTHEAST FRIDAY. NORTHEAST FLOW WILL INCREASE THROUGH THURSDAY WITH
WINDS RANGING 20 KNOTS OR GREATER BY THURSDAY NIGHT AND CONTINUING
THROUGH FRIDAY NIGHT. WINDS WILL SLOWLY DIMINISH THROUGH SATURDAY.
HIGH PRESSURE WILL BUILD OVER THE LAKE ON SUNDAY. SMALL CRAFT
ADVISORY CONDITIONS APPEAR LIKELY BEGINNING THURSDAY NIGHT AND
CONTINUING THROUGH AT LEAST SATURDAY MORNING.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...KUBINA
NEAR TERM...KUBINA
SHORT TERM...KUBINA
LONG TERM...ABE
AVIATION...ABE
MARINE...ABE
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
339 AM EDT WED AUG 8 2012
.SYNOPSIS...
A WEAK COLD FRONT JUST NORTH OF LAKE ERIE WILL MOVE SOUTHEAST ACROSS
THE LOCAL AREA TODAY AND THEN STALL NEAR THE OHIO RIVER. LOW
PRESSURE WILL MOVE UP THE OHIO VALLEY TONIGHT AND FRIDAY. HIGH
PRESSURE WILL SLOWLY BUILD OVER THE REGION FROM THE WEST OVER THE
WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
THE COLD FRONT IS ON TRACK TO MOVE SE ACROSS THE AREA TODAY. SOME
SHOWERS AND EVEN SOME LIGHTNING OCCURRED EARLIER IN THE NIGHT
ALONG THE FRONT ACROSS LOWER MICHIGAN. LATEST HRRR AND CONVECTIVE
SREF CONTINUE TO SUGGEST THAT ISOLATED TO SCATTERED SHOWERS AND
STORMS WILL DEVELOP ALONG THE FRONT LATER TODAY. BEST CHANCES FOR
THIS WILL BE IN THE EAST THIS AFTERNOON. HAVE GONE WITH A 20 TO 30
POP MOST AREAS. CLOUDS WILL COME AND GO TODAY BUT BY LATE
AFTERNOON SKIES SHOULD BE MAINLY PARTLY CLOUDY. HIGH TEMPS WILL BE
A DEGREE OR TWO COOLER THAN TUESDAY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY NIGHT/...
ACTIVE WEATHER IS EXPECTED DURING THE PERIOD AS AN UPPER LOW GETS
SET UP OVER THE EASTERN CONUS. THE MODELS NOW ARE FAIRLY SIMILAR
WITH THE MAIN FEATURES. LOW PRESSURE IS EXPECTED TO MOVE UP THE
OHIO VALLEY TONIGHT AND FRIDAY WITH THE LOW EVENTUALLY CROSSING WESTERN
PA. MODELS SHOWING GOOD ISENTROPIC LIFT WITH PWAT VALUES
EVENTUALLY REACHING 1.75 INCHES. INSTABILITY WILL INCREASE TONIGHT
AND THURSDAY AS DEWPOINTS SURGE INTO THE UPPER 60S. A FEW STRONG
TO SEVERE STORMS ARE LIKELY LATE THURSDAY AS THE LOW PASSES. SHEAR
WILL BE ENHANCED ALONG THE FRONT STRETCHING NE FROM THE LOW. THAT
IS LIKELY WHERE ANY SEVERE WEATHER WILL OCCUR. WRAP AROUND
MOISTURE BEHIND THE LOW WILL KEEP SHOWERS GOING THROUGH MIDDAY
SATURDAY ALL AREAS AND IN THE EAST ON SATURDAY NIGHT. 850 MB TEMPS
DIP TO PLUS 8 OR 10 SATURDAY DEPENDING ON WHICH MODEL YOU BELIEVE.
EITHER WAY COLD AIR ADVECTION CLOUDS AND SHOWERS WILL BE LIKELY TO
THE EAST OF KCLE. EXPECT MUCH OF THE AREA TO SEE AN INCH OR MORE
OR RAIN THURSDAY THROUGH FRIDAY. TEMPS DURING THE PERIOD WILL BE
BELOW NORMAL FOR A CHANGE.
&&
.LONG TERM /SUNDAY THROUGH TUESDAY/...
MODELS CONTINUING TO HANDLE STRONG UPPER TROUGH OVER THE AREA WELL
WITH GFS AND ECMWF MOVING IT OFF TO THE EAST ON SUNDAY WITH SFC HIGH
PRESSURE BUILDING INTO THE AREA. GOING INTO EARLY NEXT WEEK MADE
LITTLE CHANGES OVERALL TO THE FORECAST WITH 00Z ECMWF SHOWING BROAD
UPPER TROUGH MOVING ACROSS THE AREA WHILE GFS ALSO BRINGING UPPER
TROUGH OVER THE AREA BUT A BIT STRONGER WITH SFC LOW PRESSURE
DEVELOPING OVER THE MID MISSISSIPPI VALLEY. FOR NOW WILL CONTINUE TO
LEAN TOWARD THE ECMWF WITH MAINLY DRY CONDITIONS...BUT HAVE CONTINUE
WITH MORE CLOUDINESS ACROSS THE AREA DURING THIS TIME. WITH NO
STRONG TEMP ADVECTION MODERATED TEMPS FOR SUNDAY WITH THE TROUGH
DEPARTING BUT OTHERWISE KEPT THEM NEAR NORMAL FOR EARLY NEXT WEEK.
&&
.AVIATION /08Z WEDNESDAY THROUGH SUNDAY/...
A WEAK COLD FRONT N OF LAKE ERI ACROSS SRN MI WILL CONTINUE TO
SLOWLY MOVE SOUTH ACROSS SITES THROUGH TODAY. RADAR SHOWING ONE
ISOL SHRA MOVING INTO NW OH SO WILL HAVE TO WATCH TOL...BUT NOT
THINKING MUCH FOR IMPACT. OTHERWISE EXPECTING SOME CLOUDS TO
DEVELOP LATER THIS MORNING AND AFTN ACROSS NRN OH AHEAD OF THE
FRONT. THERE MAY BE SOME ISOL SHRA WITH IT BUT NOT CONFIDENT ON
OCCURRENCE OR TIMING AT ANY PARTICULAR SITES. AT THIS TIME WOULD
THINK MFD-CAK-YNG WOULD HAVE BEST CHANCE FOR SHRA THIS AFTN. SOUTH
WINDS WILL GRADUALLY TURN NORTH AFTER FROPA THROUGH TODAY.
.OUTLOOK...PERIODS OF NON VFR POSSIBLE THURSDAY AND FRIDAY ACROSS
ALL SITES. NON VFR POSSIBLE SATURDAY ACROSS EASTERN SITES.
&&
.MARINE...
A WEAK COLD FRONT WILL MOVE ACROSS THE LAKE TODAY BUT SHOULD CAUSE
ANY SIGNIFICANT WEATHER OTHER THAN THE WIND SHIFT FROM SOUTHWEST TO
NORTH TONIGHT. THE SIGNIFICANT WEATHER ISSUE FOR THE LAKE WILL BEGIN
THURSDAY AS A STRONG UPPER TROUGH MOVES TOWARD THE LAKE AND SFC LOW
PRESSURE INTENSIFIES OVER THE OHIO VALLEY...THEN MOVES TO THE
NORTHEAST FRIDAY. NORTHEAST FLOW WILL INCREASE THROUGH THURSDAY WITH
WINDS RANGING 20 KNOTS OR GREATER BY THURSDAY NIGHT AND CONTINUING
THROUGH FRIDAY NIGHT. WINDS WILL SLOWLY DIMINISH THROUGH SATURDAY.
HIGH PRESSURE WILL BUILD OVER THE LAKE ON SUNDAY. SMALL CRAFT
ADVISORY CONDITIONS APPEAR LIKELY BEGINNING THURSDAY NIGHT AND
CONTINUING THROUGH AT LEAST SATURDAY MORNING.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...KUBINA
NEAR TERM...KUBINA
SHORT TERM...KUBINA
LONG TERM...ABE
AVIATION...ABE
MARINE...ABE
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
157 AM EDT WED AUG 8 2012
.SYNOPSIS...
HIGH PRESSURE CENTERED OVER THE OHIO VALLEY WILL CONTINUE THE DRY
WEATHER OVERNIGHT TONIGHT. A WEAK COLD FRONT UNDERNEATH A MID
LEVEL DISTURBANCE WILL SLIP DOWN FROM THE NORTH ON WEDNESDAY AND
REMAIN NEAR THE OHIO RIVER THROUGH THURSDAY. A STRONG UPPER LOW
WILL MOVE INTO THE OHIO VALLEY REGION THURSDAY NIGHT AND FRIDAY
INCREASING THE CHANCE FOR PRECIPITATION.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
HIGH PRESSURE WILL BRING MOSTLY CLEAR SKIES TO OUR AREA
TO START THE OVERNIGHT PERIOD. A WEAK DISTURBANCE APPROACHING THE
NORTHERN ZONES LATE TONIGHT MAY BRING SOME SCATTERED LOW AND MID
LEVEL CLOUDS ACROSS THOSE ZONES. THE HRRR AND RAP TRY TO PRODUCE
ISOLATED SHOWERS WITH THIS FEATURE AROUND DAYBREAK. HAVE HELD OFF
ON ANY MENTIONABLE CHANCES FOR PRECIP AS THE NORTHERN ZONES HAVE
DEWPOINTS GENERALLY IN THE UPPER 50S...SO ANYTHING THAT DOES
DEVELOP WILL PROBABLY NOT HAVE PRECIP REACH THE SURFACE.
TEMPERATURES HAVE BEEN SLOW TO DROP OFF ACROSS MOST OF THE
SOUTHWEST...AND DAYTON...WILMINGTON...AND COLUMBUS METRO AREA.
HAVE THEREFORE TWEAKED UP OVERNIGHT LOWS IN THESE AREAS. ALSO OF
NOTE IS THE UPPER 60S DEWPOINTS THAT HAVE FOUND THEIR WAY INTO OUR
AREA BETWEEN THE EASTERN CINCINNATI METRO AREA AND PORTSMOUTH.
THIS COULD BE A PRECURSOR TO FOG DEVELOPMENT LATER TONIGHT
ESPECIALLY ACROSS THE RIVER VALLEYS.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH THURSDAY NIGHT/...
A WEAK COLD FRONT WILL DROP SOUTH INTO THE REGION ON WEDNESDAY.
THERE IS LITTLE SUPPORT FOR CONVECTION BUT IT WILL BRING A SLIGHT
CHANCE TO PARTS OF THE FA. THE FRONT WILL BECOME NEARLY STATIONARY
NEAR THE OHIO RIVER. TEMPERATURES ON WEDNESDAY WILL WARM UP
COMPARED TO TODAY AS WWA TAKES OVER AHEAD OF THE NEXT STRONG UPPER
LEVEL TROF. EXPECT TEMPERATURES IN THE MID 90S SOUTH TO UPPER 80S
EXTREME NORTH.
BOTH ECMWF AND GFS HAVE A LOW DEVELOPING SW ALONG THE FRONT AND
MOVING INTO THE REGION THURSDAY/THURSDAY NIGHT. THE MODELS DIFFER
THOUGH ON STRENGTH AND EXACT PLACEMENT OF THE LOW WHICH WILL
ULTIMATELY EFFECT PRECIPITATION LOCATION AND AMOUNTS. HAVE CHANCE
POPS THURSDAY INCREASING THEM TO LIKELY THURSDAY NIGHT AS DEEPER
UPPER LEVEL TROF APPROACHES FORECAST AREA.
THE HIGH TEMPERATURES WILL BE A FEW DEGREES COOLER ON THURSDAY
WITH AN INCREASE IN CLOUDS. THE LOW TEMPERATURES WILL BE IN THE
MID TO UPPER 60S WEDNESDAY NIGHT AND THURSDAY NIGHT.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
MODELS CONTINUE TO HAVE DIFFICULTY RESOLVING THE TIMING AND
STRENGTH OF DIGGING S/WV TROF INTO THE GREAT LAKES ON FRIDAY AND
HOW LONG IT LINGERS INTO THE FIRST PART OF THE UPCOMING WEEKEND.
ATTM...HAVE USED A BLEND OF THE 00Z ECMWF AND NCEP HPC GUIDANCE IN
WHICH SFC LOW PRESSURE IS MORE SUBDUED AND RIPPLES ALONG OLD
FRONTAL BOUNDARY ALONG THE OHIO RIVER ON FRIDAY. THIS SOLUTION
CALLS FOR LIKELY POPS AND TEMPERATURES ON THE COOLER SIDE DUE TO
CLOUDS...PCPN...AND SOME LOCATIONS UNDER THE INFLUENCE OF A
NORTHERLY FLOW ON THE BACK SIDE OF THE LOW. HOWEVER...IT MUST BE
NOTED THAT THE NEW 12Z ECMWF IS GIVING INDICATIONS SIMILAR TO THE
12Z GFS THAT PERHAPS THE SFC LOW WILL DEEPEN AND TRACK FARTHER NW
ALONG I-71. THIS LATTER SOLUTION WOULD BRING A SHARPER TEMPERATURE
GRADIENT TO THE REGION AND COULD POSE A SMALL RISK OF SEVERE
WEATHER TO AREAS LOCATED SE OF THE LOW TRACK. HOPEFULLY...LATER
MODEL RUNS WILL RESOLVE THIS DILEMMA...BUT MODELS TEND TO HAVE
DIFFICULTY IN DIGGING AND DEVELOPING CLOSED MID LEVEL
CIRCULATIONS.
FOR FRIDAY NIGHT NIGHT INTO SATURDAY NIGHT...AGAIN...A QUICKER UPR
LVL LOW MOTION TO THE NE WAS USED BUT MAY END UP BEING SLOWER THAN
CURRENTLY FORECAST DUE TO RECENT MODEL GUIDANCE. HAVE A CHANCE OF
SHOWERS DIMINISHING WEST TO EAST THROUGH THIS PERIOD ALONG WITH
GRADUAL CLEARING SATURDAY INTO SATURDAY NIGHT. TEMPERATURES ON
SATURDAY WILL BE CLOUD DEPENDENT AND HAVE GONE WITH HIGHS IN THE MID
TO UPPER 70S. LOWS SATURDAY NIGHT WILL BE COOL AS SURFACE HIGH
PRESSURE BUILDS INTO THE REGION.
FOR THE REMAINDER OF THE EXTENDED...SUNDAY THROUGH TUESDAY...THE
GREAT LAKES AND OHIO VALLEY AREA WILL BE UNDER A NORTHWEST FLOW
PATTERN ALOFT. THERE ARE INDICATIONS THAT A FEW WEAK DISTURBANCES
WILL RIPPLE SE WITHIN THIS FLOW...BRINGING A SMALL THREAT FOR PCPN.
GIVEN THAT THEY APPEAR WEAK ATTM AND TIMING IS DIFFICULT AT BEST AT
THIS JUNCTURE...HAVE MAINTAINED A DRY FORECAST ALONG WITH MODIFYING
TEMPERATURES AS HEIGHTS AND TEMPERATURES ALOFT RISE THROUGH THE
PERIOD.
&&
.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
SEEING SOME 8K FT AC DEVELOPING ACROSS THE MIAMI AND WHITEWATER
VALLEYS. THIS IS EXPECTED TO GRADUALLY WORK EWD OVERNIGHT. KEPT
THESE CLDS SCT FOR THE OVERNIGHT. MVFR AND POSSIBLE SOME IFR FOG
ARE POSSIBLE UNTIL 12Z AT ILN AND LUK.
WEAK CDFNT WORKS INTO THE FA TODAY. MOISTURE IS RATHER
LIMITED...SO ONLY EXPECT CLDS DEVELOPMENT WITH THE FNTL LIFT.
MODELS ARE SUGGESTING THAT THE BEST CLDS COVER WILL BE DURING THE
LATE AFTN ALONG FRONT WHEN IT REACH AN ARC FROM CMH-PMH-CVG. WENT
A WITH A BROKEN AC DECK AT CVG/LUK...BUT LEFT THE CLDS SCT AT THE
OTHER TAFS.
UPPER LEVEL MOISTURE WILL BEGIN TO INCREASE AFT 00Z AHEAD OF A
STRONGER SYSTEM THAT IS DIGGING INTO THE MS VALLEY.
.OUTLOOK...THUNDERSTORMS ARE POSSIBLE ON THURSDAY AND FRIDAY.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...PARKER
NEAR TERM...LATTO
SHORT TERM...PARKER
LONG TERM...HICKMAN
AVIATION...SITES
AREA FORECAST DISCUSSION
NWS TULSA OK
343 PM CDT WED AUG 8 2012
.DISCUSSION...
ONGOING CONVECTION WILL MAINTAIN A RISK OF DAMAGING DOWNBURST
WINDS ACROSS SE OK AND WESTERN AR INTO SUNSET...WITH ATTENTION
THEN TURNING TO EXPANDING CONVECTION ACROSS THE CENTRAL PLAINS.
THIS CONVECTION WILL BE FORCED BY A RESPECTABLE MID LEVEL WAVE FOR
EARLY AUGUST...AND LIKELY DEVELOP SOUTH AND EASTWARD AFTER SUNSET.
GIVEN THE DEEPLY MIXED AND NOT-YET OVERTURNED BOUNDARY LAYER IN
PLACE ACROSS NE OK...THE CONVECTION WILL HAVE A GOOD CHANCE OF
DEVELOPING INTO THE REGION. THE SOUTHWARD EXTENT SHOULD BE LIMITED
BY THE ONGOING CONVECTION AND ITS EFFECTS ON STABILIZING THE
BOUNDARY LAYER. THIS SCENARIO IS LARGELY SUPPORTED BY THE 18Z NAM
AND HRRR OUTPUT.
THE COLD FRONT ASSOCIATED WITH THE PASSING WAVE WILL MOVE INTO NE
OK BY SUNRISE THURSDAY...AND THROUGH MUCH OF THE FORECAST AREA BY
SUNSET THURSDAY. STORM CHANCES WILL RESIDE ALONG AND SOUTH OF THE
BOUNDARY PRIMARILY DURING THE AFTERNOON HOURS ON THURSDAY.
NOTICEABLY DRIER AND COOLER AIR WILL FOLLOW THE FRONT AND BRING
TEMPS NEAR NORMAL FRIDAY AND SATURDAY. RAINFALL FOOTPRINTS...OR
LACK THEREOF...MAY LARGELY AFFECT THE DEGREE OF COOLING GIVEN THE
VERY WARM GROUND TEMPS AND LACK OF CLOUD COVER BEHIND THE FRONT.
UPPER RIDGING WILL ATTEMPT TO EXPAND BACK EASTWARD OVER THE
WEEKEND...THOUGH IT LOOKS TO BE SUPPRESSED FURTHER SOUTH AND NOT
HAVE AS STRONG AS INFLUENCE AS RECENTLY. SOUTHERN PERIPHERY OF A
PASSING WAVE MAY SUPPORT PRECIP LATE SUNDAY INTO
MONDAY...OTHERWISE NO SIGNIFICANT PRECIP CHANCES ARE NOTED UNTIL
POSSIBLY JUST BEYOND THIS FORECAST TIME FRAME.
&&
.PRELIMINARY POINT TEMPS/POPS...
TUL 75 100 69 92 / 30 0 10 0
FSM 78 104 70 93 / 30 20 10 0
MLC 74 103 69 94 / 30 20 10 0
BVO 69 99 64 92 / 30 0 10 0
FYV 67 97 64 87 / 40 10 10 0
BYV 70 95 66 85 / 50 10 10 0
MKO 73 102 69 93 / 40 0 10 0
MIO 71 97 68 88 / 40 0 10 0
F10 75 102 70 93 / 30 10 10 0
HHW 75 103 73 95 / 30 30 10 0
&&
.TSA WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
AR...NONE.
&&
$$
LONG TERM....07
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
1112 AM EDT WED AUG 8 2012
.SYNOPSIS...
A BROAD UPPER LEVEL TROUGH OVER THE EASTERN U.S. WILL UNDERGO
SIGNIFICANT AMPLIFICATION THROUGH THE END OF THE WEEK. THIS
FEATURE AND ITS ASSOCIATED FRONTAL SYSTEM WILL BRING RAIN AND
THUNDERSTORMS TO THE AREA INTO THE FIRST PART OF THE WEEKEND.
FAIR WEATHER SHOULD RETURN BY LATE IN THE WEEKEND OR EARLY NEXT
WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
WEAK FRONTAL BOUNDARY ACROSS NW PA WILL BE FOCUS OF SCATTERED
CONVECTION THIS AFTERNOON. ANY STORMS THAT DO FORM WILL DRIFT
SOUTHEAST ACROSS THE CWA. AFTERNOON CAPES WILL BE MARGINAL AND
SHEAR WEAK...THOUGH LATEST HRRR RUNS DEVELOP CONVECTION. WILL
RAISE POPS SLIGHTLY IN NW ZONES TO ACCOUNT FOR THIS. STILL NOT
EXPECTING MUCH MORE THEN PULSE STORMS. ANOTHER BOUNDARY SE OF PA
WILL BE CLOSE ENOUGH TO SE ZONES TO BRING A CHANCE OF AFTERNOON
CONVECTION...BUT LACK OF TRIGGER AND WARMER MID LEVEL TEMPS SUGGESTS
NOTHING MORE THAN AN ISOLD PULSE STORM. OVERALL CONVECTIVE CVRG
SHOULD BE LIMITED AND CAPPED POPS AT 30 PCT.
THE WEAK FRONT WILL SETTLE SLOWLY SEWD NEAR I-80 OVERNIGHT. A FEW
SHOWERS OR TSTMS MAY STILL LINGER NEAR THE DIFFUSE FRONT...BUT
THE LOSS OF HEATING/INSTABILITY SHOULD AFFORD A DRY NIGHT IN MOST
LOCATIONS. HI/LO TEMPS THIS PD WILL AVG A FEW TO SEVERAL DEGS ABV
NORMAL.
&&
.SHORT TERM /THURSDAY THROUGH THURSDAY NIGHT/...
SIGNIFICANT AMPLIFICATION OF THE ERN TROUGH IS EXPECTED TO BEGIN
THIS PERIOD...AS POTENT S/W AND ATTENDANT MID-LVL JET DROP SEWD
INTO THE GRT LKS AND MID MS VLY. AT THE SFC...THE
BAROCLINIC/FRONTAL ZONE SHOULD BECOME MORE DEFINED IN TIME WITH
ONE OR MORE SFC WAVES DEVELOPING IN THE OH VLY. THE ERN PORTION OF
THE WAVY FNTL BNDRY SHOULD REMAIN Q-STNRY OVR CENTRAL PA THRU
THURS NIGHT.
SPC HAS MAINTAINED THE SLIGHT RISK FOR ALL OF THE CWA FOR D2. THE
SLIGHTLY ELEVATED SVR THREAT..WHEN COMPARED TO THE D1 SEE TEXT...
IS SUPPORTED BY STRONGER DEEP LYR FORCING/HEIGHT FALLS AND WINDS
ALOFT. 1500-2000 J/KG OF ML CAPE AND FAIRLY STEEP MID-LVL LAPSE
RATES SHOULD ALSO ENHANCE DMGG WIND THREAT VIA LOOSELY ORGANIZED
MULTI-CELL CLUSTERS.
THE WELL-DEFINED POS TILT S/W TROUGH WILL ROTATE EWD THRU THE
MIDWEST TWD THE UPPER OH VLY BY THE END OF THE PD. MDL DATA SHOWS
AN AXIS OF MOD-HVY RNFL SETTING UP ALONG SEWD ADVANCING FNTL ZONE
JUST DOWNWIND OF THE LWR GRT LKS. INC SWLY FLOW AHEAD OF DEEPENING
SFC WAVE EJECTING NEWD THRU THE OH VLY SHOULD DRAW HI PWATS NEWD
INTO NW PA. FAVORABLE UPPER JET DYNAMICS AND STRONG LLVL
CONVERGENCE SHOULD SUPPORT 0.50-1 INCH QPF AXIS OVR THIS REGION
AND HAVE INCREASED POPS INTO THE LOW CATG RANGE. A NON-GFS
SOLUTION IS PREFERRED WITH THIS SYSTEM.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
THE ANOMALOUS MID-UPPER TROUGH IS FORECAST TO EVOLVE INTO A CLOSED
LOW INVOF LWR MI ON FRIDAY...AND THEN LIFT SLOWLY NWD ACRS THE LWR
GRT LKS INTO SRN ONT ON SAT BEFORE ACCELERATING INTO QUEBEC ON
SUNDAY. CONCERNING THE H5 LOW POSITION...THE GFS IS A NRN OUTLIER
WITH THIS SYSTEM AND THE 00Z GEFS AND 12Z ECENS MEAN SUPPORT A MORE
SOUTHERLY/SLOWER SOLUTION ALOFT PER THE REMAINING DETERMINISTIC
GLOBAL MODEL CONSENSUS -- 00Z UKMET/CANADIAN/ECMWF.
SEVERAL WEAK WAVES OF LOW PRES IN THE OH VLY WILL CONSOLIDATE INTO
ONE MAIN SFC LOW INVOF LAKE ERIE EARLY FRI BEFORE OCCLUDING NWWD OVR
THE LWR LKS TWD LAKE HURON BY SATURDAY. THE WARM FRONT ATTENDANT TO
THE SFC LOW WILL LIFT NEWD THRU PA INTO NEW ENGLAND WHILE THE
TRAILING COLD FRONT PIVOTS EWD ACRS THE UPPER OH VLY AND PUSHES
SLOWLY EWD THRU CENTRAL PA.
A SSW-NNE ORIENTED MOD-HVY QPF AXIS SHOULD BE ONGOING AT THE
START OF THE PERIOD ACRS NW PA NEAR SFC LOW TRACK. GENERALLY
LIGHTER BASIN-AVG QPF AMTS...MORE CONVECTIVE IN NATURE... ARE
ANTICIPATED FURTHER TO THE EAST ACRS THE CENTRAL MTNS AND SUSQ
VLY LATER FRIDAY AND INTO FRI NGT ALONG/AHEAD OF THE COLD FRONT.
STRONG JET DYNAMICS AND FRONTAL LIFT/CONVERGENCE COULD PRODUCE
HVY RNFL RATES WITH PLENTY OF DEEP LYR MSTR AVAILABLE. FOLLOWED
HPC PRETTY CLOSELY FOR QPF AMTS WHICH RANGE FROM 1-1.5 INCHES OVR
THE NW MTNS TO 0.25-0.50 IN THE LWR SUSQ VLY FOR THE 24HR PD
ENDING 00Z SAT. IN ADDITION TO POSSIBLE HVY RAINS...A SVR WEATHER
THREAT SHOULD ALSO UNFOLD AHEAD OF THE COLD FRONT IN THE VERY
MOIST WARM SECTOR. SPC HAS EXPANDED THE D3 SLIGHT RISK TO
ENCOMPASS NEARLY ALL OF THE CWA EAST OF THE ALLEGHENY FRONT. THERE
WILL BE A SOMEWHAT CONDITIONAL DMGG WIND THREAT AS STRONG WARMING
OCCURS IN CLOUD-BREAKS AND CONTRIBUTES TO POTENTIAL MODERATE
INSTABILITY. ANOTHER SCENARIO TO CONSIDER IS THE DEVELOPMENT OF A
SECONDARY TRIPLE POINT LOW E OF THE APPLCHNS...WHICH MAY ACT TO
ENHANCE LOW LEVEL SHEAR INVOF WARM FRONTAL ZONE NEAR SE PA.
BROAD CYC FLOW ALOFT WILL OVERSPREAD THE REGION SAT INTO EARLY
SUNDAY WHICH SHOULD ALLOW FOR SCT SHOWER/ISOLD TSTM ACTIVITY.
THERE ALSO APPEARS TO BE A DEFORMATION ZONE WHICH COULD SPREAD WRAP-
AROUND PCPN INTO THE AREA ON THE BACKSIDE OF THE DEPARTING SYS. PCPN
SHOULD COME TO AN END ON SUNDAY AS THE SYSTEM BEGINS TO ACCELERATE
NWD. A PERIOD OF FAIR AND FAIRLY UNEVENTFUL WEATHER WILL LKLY
FOLLOW INTO EARLY NEXT WEEK AS THE WESTERLIES RELAX TO A QUASI-ZONAL
ORIENTATION.
&&
.AVIATION /15Z WEDNESDAY THROUGH SUNDAY/...
A WEAKENING COLD FRONT MAY SPARK OFF SOME SCATTERED
SHOWERS/STORMS OVER THE NWRN HALF OF THE FCST AREA LATE IN THE
DAY...BUT CONFIDENCE IS LOW AS THE FORCING WILL BE WEAK AND PWATS
WILL BE NOMINAL.
OUTLOOK...
THU...VFR WITH SCT SHRA/TSRA POSS AFTN/NIGHT.
FRI-SAT...MAINLY VFR BUT RESTRICTIONS LIKELY IN TSRA/SHRA.
SUN...SCATTERED SHOWERS/THUNDERSTORMS. RESTRICTIONS POSSIBLE.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...STEINBUGL
NEAR TERM...ROSS
SHORT TERM...STEINBUGL
LONG TERM...STEINBUGL
AVIATION...ROSS
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
1011 PM CDT THU AUG 9 2012
.UPDATE...
OTHER THAN THE ISOL CONVECTION OVER WESTERN MIDDLE TN...NOT MUCH
GOING ON. BOUNDARY STILL LOCATED A GOOD DISTANCE TO OUR NW.
NUMERICAL POPS ARE QUITE LOW THROUGH 12Z. HRRR NOW SHOWING SOME
REDEVELOPMENT WITH THE FRONTAL BOUNDARY AFT 08Z OR SO. PRESSURE
RISES ARE FAIRLY STRONG NORTH OF THE FRONTAL BOUNDARY.
THUS...BOUNDARY SHOULD STILL BE ON THE APPROACH THROUGH 12Z.
WILL GO AHEAD AND LOWER POPS TO THE 30-40 PERCENT RANGE FOR THE
DURATION. HRRR DOES MAKE A COMEBACK WITH THE CONVECTION BUT
PRIMARILY IS SERVING AS THE LONE MODEL...AND EVEN IF THE HRRR PANS
OUT...THE ACTIVITY DOES NOT LOOK ALL THAT ORGANIZED.
FOR THE UPDATE WILL LOWER POPS. UPDATE OUT SHORTLY.
&&
.PREV DISCUSSION... /ISSUED 703 PM CDT THU AUG 9 2012/
UPDATE...FOR 06Z AVIATION DISCUSSION.
AVIATION...06Z AVIATION DISCUSSION.
UNCERTAINTIES...SFC FRONTAL MOVEMENT IMPACTS. CONVECTION TO OUR NW
AHEAD OF FRONT MAINLY DISSIPATED...AND WITH AN OVERALL DRIER AIRMASS
IN PLACE ACROSS THE MID STATE PER MORNING`S CONVECTION...PCPN CHANCES
SLIGHT AT BEST THRU 10/10Z AND WILL NOT MENTION. AS SFC FRONT MOVES
CLOSER/EVENTUALLY THRU CKV/BNA...EXPECT SOME MOISTURE POOLING IN ITS
VICINITY...MENTIONED MVFR FOG/CEILINGS...TEMPO IFR CSV...BUT EVEN
WITH POSSIBLE SHORT WAVE PASSAGE IN UPPER LEVEL FLOW AIDING...JUST
DOUBT WITH ANY DIURNAL INFLUENCES NOT YET ESTABLISHED...PCPN WILL OCCUR.
FRONT SHOULD BE W OF CSV THRU AROUND 10/18Z...AND BELIEVE WITH DIURNAL
INFLUENCES KICKING IN...THAT CB/VCTS TSTM CSV APPROPRIATE.
PREV DISCUSSION.../ISSUED 602 PM CDT THU AUG 9 2012/
UPDATE...
NOT IMPRESSED WITH THE CHANCES FOR CONVECTION OVERNIGHT. ONLY
BULLISH TRENDS I SEE ARE WITH THE WRF AND THE FROPA WHICH IS
EXPECTED AT 12Z. OTW...UPPER DYNAMICS LOOKING WEAK WITH AN OVERALL
DECREASE IN MOISTURE DEPTH FROM 00Z TO 06Z. HRRR SHOWS ZILCH
THROUGH 6Z AND UPPER DIVERGENCE QUITE WEAK THROUGH 12Z ON THE GFS
AND NAM. I WILL GO AHEAD AND UPDATE GRIDS AD KNOCK POPS DOWN
PRIOR TO 06Z. AFT 06Z...WILL KEEP THE LIKELY POPS GOING ACROSS THE
NORTH BUT THIS MAY NEED A DOWNWARD YANK AS WELL LATER IN THIS
SHIFT.
REMAINDER OF FCST LOOKS TO BE IN GOOD SHAPE. NO MENTION OF FOG
CURRENTLY AND I SEE NO REASON TO ADD ANY AS TOVERS REMAIN NEAR TO
ABOVE 0. MIN TEMP FCST LOOKS TO BE IN GOOD SHAPE. UPDATE OUT SHORTLY.
PREV DISCUSSION.../ISSUED 340 PM CDT THU AUG 9 2012/
SHORT TERM...SHOWERS AND CLOUDS THAT STILL LINGERED ALONG THE
CUMBERLAND PLATEAU AT MID-AFTERNOON WERE HELPING TO PRODUCE A
SIGNIFICANT TEMPERATURE GRADIENT ACROSS THE MID STATE. AT 300
PM...TEMPERATURES RANGED FROM THE UPPER 60S AT CSV TO THE UPPER
80S OVER OUR MOST WESTERN COUNTIES.
WITH SHOWERS DEPARTING OUR AREA, FROM THE PLATEAU, WE NOW TURN OUR
EYES TO THE WEST, WHERE NEW THUNDERSTORMS WERE POPPING UP IN THE
AFTERNOON HEAT, OVER SOUTHWESTERN KENTUCKY. THESE STORMS WERE ALSO
OCCURRING ALONG THE EDGE OF A BAND OF MID-T0-UPPER LEVEL DRYING
THAT EXTENDED FROM SOUTHERN PARTS OF INDIANA AND ILLINOIS, ACROSS
SOUTHEAST MISSOURI INTO CENTRAL ARKANSAS. WITH THE POSSIBILITY OF
DRY AIR ENTRAINMENT AT THE MID LEVELS, EXPECT SOME GUSTY
DOWNBURSTS TO BE POSSIBLE WITH THESE STORMS AS THEY ADVANCE INTO
NORTHWESTERN MIDDLE TENNESSEE LATE THIS AFTERNOON AND EVENING.
AFTER THE INITIAL CONVECTION THIS EVENING, THAT DEVELOPS MAINLY
OVER THE NORTHWEST, BELIEVE WE WILL SEE MORE THUNDERSTORM
DEVELOPMENT LATER TONIGHT, AS UPPER TROUGH DEEPENS OVER THE OHIO
RIVER VALLEY, ENERGIZING THE SLEEPY STATIONARY FRONT JUST WEST OF
PADUCAH, AND BRINGING IT EASTWARD AS A COLD FRONT.
EXPECT THE COLD FRONT TO BE NEAR A BWG-BNA-WAYNESBORO LINE BY 12Z
FRIDAY, PUSHING TO NR A MSL-LIVINGSTON LINE BY 18Z, AND OFF THE
CUMBERLAND PLATEAU BY LATE FRIDAY AFTERNOON.
SPC HAS ALL OF OUR AREA IN A SLIGHT RISK FOR SEVERE THUNDERSTORMS
THROUGH 12Z FRIDAY, AS THE FRONT PUSHES IN, AND EXPECT TO SEE
SIMILAR STORMS TO THE ONES WE HAD THIS MORNING...VERY WET AND
JUICY (WITH TORRENTIAL DOWNPOURS) ALONG WITH THE POSSIBILITY FOR
STRONG, GUSTY DOWNBURST WINDS.
EXPECT SHOWERS AND STORMS TO FINALLY PUSH EAST OF THE MID STATE FRIDAY
EVENING, WITH SEVERAL DAYS OF DRY AND AUTUMN-LIKE CONDITIONS TO
FOLLOW OVER THE WEEKEND. EXPECT AFTERNOON DEW POINTS IN THE 50S
BOTH SATURDAY AND SUNDAY, WITH DAYTIME HIGHS MAINLY IN THE MIDDLE
80S. MANY PLACES WILL LIKELY SEE LOW TEMPERATURES DROP INTO THE
MID TO UPPER 50S SUNDAY MORNING.
LONG TERM...AFTER OUR DRY SPELL OVER THE WEEKEND, EXPECT
NORTHWEST FLOW TO BECOME MORE ZONAL, WITH TWO OR THREE UPPER LEVEL
SHORTWAVES LIKELY TO TRAVERSE THE AREA NEXT WEEK. THE TIMING OF
THESE IMPULSES, OF COURSE, IS VERY DIFFICULT. IT`S ALSO DIFFICULT
TO KNOW HOW MUCH SHRA/TSRA ACTIVITY EACH ONE WITH BRING WITH IT.
THEREFORE, HAVE PAINTED POPS WITH A BROAD BRUSH FOR MOST OF NEXT
WEEK, WITH A 20% POP MAKING REPEATED ONSTAGE APPEARANCES.
TEMPERATURES WILL WARM BACK TO AROUND 90 DEGREES OR IN THE LOWER
90S FOR AREAS WEST OF THE CUMBERLAND PLATEAU, WITH TEMPS FORECAST
TO BE MAINLY IN THE MIDDLE 80S ALONG THE PLATEAU ITSELF.
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
21
AREA FORECAST DISCUSSION
NWS MEMPHIS TN
857 PM CDT THU AUG 9 2012
.UPDATE...
DO NOT FEEL LIKE CHANCES FOR STRONG TO SEVERE THUNDERSTORMS ARE
VERY HIGH TONIGHT...BUT WITH A FRONT MOVING THROUGH IN MIDDLE
AUGUST NOT TOTALLY COMFORTABLE WITH REMOVING IT ALL TOGETHER.
LOWERED POPS A BIT. TEMPERATURES LOOK ON TRACK.
&&
.PREV DISCUSSION... /ISSUED 639 PM CDT THU AUG 9 2012/
DISCUSSION... /ISSUED 304 PM CDT THU AUG 9 2012/
SKIES ARE MOSTLY SUNNY THIS AFTERNOON ACROSS MUCH OF THE FORECAST
AREA WITH TEMPERATURES RANGING FROM THE MID 80S TO MID 90S. THE
AREA OF RAIN THAT WAS OVER PARTS OF NORTH MISSISSIPPI THIS MORNING
HAS PUSHED SOUTH. COLD FRONT CURRENTLY EXTENDS FROM EASTERN OHIO
THROUGH SOUTHEAST MISSOURI AND INTO THE TEXAS PANHANDLE. A COUPLE
OF THUNDERSTORMS HAVE DEVELOPED AHEAD OF THE FRONT OVER WESTERN
KENTUCKY AND ARE TRACKING SOUTHEAST TOWARD THE FORECAST AREA.
THE COLD FRONT WILL CONTINUE TO TRACK SOUTHEAST TONIGHT WITH SOME
ADDITIONAL SCATTERED THUNDERSTORMS EXPECTED TO DEVELOP AHEAD OF
THE FRONT. THE FRONT WILL STILL BE OVER NORTH MISSISSIPPI FRIDAY
MORNING SO SOME ADDITIONAL SCATTERED THUNDERSTORMS WILL BE
POSSIBLE MAINLY OVER AREA SOUTH OF INTERSTATE 40. BEHIND THE FRONT
COOLER AND DRIER AIR WILL FILTER INTO THE REGION. TEMPERATURES
WILL BE MUCH COOLER WITH HIGHS ONLY IN THE 80S TO AROUND 90.
BY FRIDAY NIGHT...THE FRONT WILL BE WELL SOUTH OF THE REGION
ENDING THE THREAT OF RAIN. WITH DRIER AIR IN PLACE TEMPERATURES
WILL COOL OFF SOME WITH SOME LOCATIONS IN WEST TENNESSEE DROPPING
BELOW 60 DEGREES BY SATURDAY MORNING. THE WEEKEND LOOKS TO BE
QUITE PLEASANT AS HIGH PRESSURE REMAINS IN PLACE. DRY WEATHER WILL
CONTINUE FOR BOTH SATURDAY AND SUNDAY WITH TEMPERATURES MAINLY
BELOW NORMAL BOTH DAYS.
BY MONDAY...A WEAK COLD FRONT WILL BE APPROACHING THE REGION WITH
SOME SCATTERED THUNDERSTORMS POSSIBLE AHEAD OF THE FRONT. THE
FRONT WILL CONTINUE TO MOVE SLOWLY SOUTHEAST MONDAY NIGHT AND
TUESDAY WITH MORE SCATTERED THUNDERSTORMS POSSIBLE FROM MONDAY
NIGHT THROUGH TUESDAY NIGHT.
HIGH PRESSURE WILL BRIEFLY BUILD INTO THE REGION ON WEDNESDAY
BRINGING A BRIEF END TO THE THREAT OF RAIN. BY WEDNESDAY NIGHT THE
COLD FRONT WILL LIFT BACK NORTH AS A WARM FRONT BRINGING A CHANCE
OF MORE THUNDERSTORMS FOR WEDNESDAY NIGHT AND MUCH OF THURSDAY.
ARS
AVIATION...
00Z TAF SET
COLD FRONT STILL LOCATED BACK TO THE NORTHWEST BUT LOWER DEWPOINTS
HAVE WORKED INTO MUCH OF THE CWA THUS BEGINNING TO HAVE DOUBTS ON TSRA
DEVELOPMENT THIS EVENING ALONG THE FRONT. LATEST HRRR RUN DOESN/T
SHOW ANYTHING DEVELOPING AND THE NEW NAM SHOWS STUFF DEVELOPING
NOT UNTIL THE FRONT IS SOUTH AND EAST OF MEMPHIS. FOR NOW WILL
REMOVE MENTION OF VCTS AT KJBR BUT WILL LEAVE VCTS WORDING AT
OTHER TAF SITES. SOUTHWEST WINDS AROUND 8-10 KTS WITH HIGHER GUSTS
AT TIMES EXPECTED AHEAD OF THE FRONT. WINDS WILL SWITCH TO THE
NORTHWEST AND EVENTUALLY TO THE NORTH BEHIND THE FRONT.
KRM
&&
.AVIATION...
&&
.PRELIMINARY POINT TEMPS/POPS...
MEM 74 87 67 88 / 20 20 10 0
MKL 69 84 59 86 / 30 20 0 0
JBR 71 87 64 89 / 10 10 0 0
TUP 72 89 65 88 / 30 30 10 0
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
MO...NONE.
MS...NONE.
TN...NONE.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS NASHVILLE TN
703 PM CDT THU AUG 9 2012
.UPDATE...FOR 06Z AVIATION DISCUSSION.
&&
.AVIATION...06Z AVIATION DISCUSSION.
UNCERTAINTIES...SFC FRONTAL MOVEMENT IMPACTS. CONVECTION TO OUR NW
AHEAD OF FRONT MAINLY DISSIPATED...AND WITH AN OVERALL DRIER AIRMASS
IN PLACE ACROSS THE MID STATE PER MORNING`S CONVECTION...PCPN CHANCES
SLIGHT AT BEST THRU 10/10Z AND WILL NOT MENTION. AS SFC FRONT MOVES
CLOSER/EVENTUALLY THRU CKV/BNA...EXPECT SOME MOISTURE POOLING IN ITS
VICINITY...MENTIONED MVFR FOG/CEILINGS...TEMPO IFR CSV...BUT EVEN
WITH POSSIBLE SHORT WAVE PASSAGE IN UPPER LEVEL FLOW AIDING...JUST
DOUBT WITH ANY DIURNAL INFLUENCES NOT YET ESTABLISHED...PCPN WILL OCCUR.
FRONT SHOULD BE W OF CSV THRU AROUND 10/18Z...AND BELIEVE WITH DIURNAL
INFLUENCES KICKING IN...THAT CB/VCTS TSTM CSV APPROPRIATE.
&&
.PREV DISCUSSION.../ISSUED 602 PM CDT THU AUG 9 2012/
UPDATE...
NOT IMPRESSED WITH THE CHANCES FOR CONVECTION OVERNIGHT. ONLY
BULLISH TRENDS I SEE ARE WITH THE WRF AND THE FROPA WHICH IS
EXPECTED AT 12Z. OTW...UPPER DYNAMICS LOOKING WEAK WITH AN OVERALL
DECREASE IN MOISTURE DEPTH FROM 00Z TO 06Z. HRRR SHOWS ZILCH
THROUGH 6Z AND UPPER DIVERGENCE QUITE WEAK THROUGH 12Z ON THE GFS
AND NAM. I WILL GO AHEAD AND UPDATE GRIDS AD KNOCK POPS DOWN
PRIOR TO 06Z. AFT 06Z...WILL KEEP THE LIKELY POPS GOING ACROSS THE
NORTH BUT THIS MAY NEED A DOWNWARD YANK AS WELL LATER IN THIS
SHIFT.
REMAINDER OF FCST LOOKS TO BE IN GOOD SHAPE. NO MENTION OF FOG
CURRENTLY AND I SEE NO REASON TO ADD ANY AS TOVERS REMAIN NEAR TO
ABOVE 0. MIN TEMP FCST LOOKS TO BE IN GOOD SHAPE. UPDATE OUT SHORTLY.
PREV DISCUSSION.../ISSUED 340 PM CDT THU AUG 9 2012/
SHORT TERM...SHOWERS AND CLOUDS THAT STILL LINGERED ALONG THE
CUMBERLAND PLATEAU AT MID-AFTERNOON WERE HELPING TO PRODUCE A
SIGNIFICANT TEMPERATURE GRADIENT ACROSS THE MID STATE. AT 300
PM...TEMPERATURES RANGED FROM THE UPPER 60S AT CSV TO THE UPPER
80S OVER OUR MOST WESTERN COUNTIES.
WITH SHOWERS DEPARTING OUR AREA, FROM THE PLATEAU, WE NOW TURN OUR
EYES TO THE WEST, WHERE NEW THUNDERSTORMS WERE POPPING UP IN THE
AFTERNOON HEAT, OVER SOUTHWESTERN KENTUCKY. THESE STORMS WERE ALSO
OCCURRING ALONG THE EDGE OF A BAND OF MID-T0-UPPER LEVEL DRYING
THAT EXTENDED FROM SOUTHERN PARTS OF INDIANA AND ILLINOIS, ACROSS
SOUTHEAST MISSOURI INTO CENTRAL ARKANSAS. WITH THE POSSIBILITY OF
DRY AIR ENTRAINMENT AT THE MID LEVELS, EXPECT SOME GUSTY
DOWNBURSTS TO BE POSSIBLE WITH THESE STORMS AS THEY ADVANCE INTO
NORTHWESTERN MIDDLE TENNESSEE LATE THIS AFTERNOON AND EVENING.
AFTER THE INITIAL CONVECTION THIS EVENING, THAT DEVELOPS MAINLY
OVER THE NORTHWEST, BELIEVE WE WILL SEE MORE THUNDERSTORM
DEVELOPMENT LATER TONIGHT, AS UPPER TROUGH DEEPENS OVER THE OHIO
RIVER VALLEY, ENERGIZING THE SLEEPY STATIONARY FRONT JUST WEST OF
PADUCAH, AND BRINGING IT EASTWARD AS A COLD FRONT.
EXPECT THE COLD FRONT TO BE NEAR A BWG-BNA-WAYNESBORO LINE BY 12Z
FRIDAY, PUSHING TO NR A MSL-LIVINGSTON LINE BY 18Z, AND OFF THE
CUMBERLAND PLATEAU BY LATE FRIDAY AFTERNOON.
SPC HAS ALL OF OUR AREA IN A SLIGHT RISK FOR SEVERE THUNDERSTORMS
THROUGH 12Z FRIDAY, AS THE FRONT PUSHES IN, AND EXPECT TO SEE
SIMILAR STORMS TO THE ONES WE HAD THIS MORNING...VERY WET AND
JUICY (WITH TORRENTIAL DOWNPOURS) ALONG WITH THE POSSIBILITY FOR
STRONG, GUSTY DOWNBURST WINDS.
EXPECT SHOWERS AND STORMS TO FINALLY PUSH EAST OF THE MID STATE FRIDAY
EVENING, WITH SEVERAL DAYS OF DRY AND AUTUMN-LIKE CONDITIONS TO
FOLLOW OVER THE WEEKEND. EXPECT AFTERNOON DEW POINTS IN THE 50S
BOTH SATURDAY AND SUNDAY, WITH DAYTIME HIGHS MAINLY IN THE MIDDLE
80S. MANY PLACES WILL LIKELY SEE LOW TEMPERATURES DROP INTO THE
MID TO UPPER 50S SUNDAY MORNING.
LONG TERM...AFTER OUR DRY SPELL OVER THE WEEKEND, EXPECT
NORTHWEST FLOW TO BECOME MORE ZONAL, WITH TWO OR THREE UPPER LEVEL
SHORTWAVES LIKELY TO TRAVERSE THE AREA NEXT WEEK. THE TIMING OF
THESE IMPULSES, OF COURSE, IS VERY DIFFICULT. IT`S ALSO DIFFICULT
TO KNOW HOW MUCH SHRA/TSRA ACTIVITY EACH ONE WITH BRING WITH IT.
THEREFORE, HAVE PAINTED POPS WITH A BROAD BRUSH FOR MOST OF NEXT
WEEK, WITH A 20% POP MAKING REPEATED ONSTAGE APPEARANCES.
TEMPERATURES WILL WARM BACK TO AROUND 90 DEGREES OR IN THE LOWER
90S FOR AREAS WEST OF THE CUMBERLAND PLATEAU, WITH TEMPS FORECAST
TO BE MAINLY IN THE MIDDLE 80S ALONG THE PLATEAU ITSELF.
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
31
AREA FORECAST DISCUSSION
NWS MEMPHIS TN
639 PM CDT THU AUG 9 2012
.DISCUSSION... /ISSUED 304 PM CDT THU AUG 9 2012/
SKIES ARE MOSTLY SUNNY THIS AFTERNOON ACROSS MUCH OF THE FORECAST
AREA WITH TEMPERATURES RANGING FROM THE MID 80S TO MID 90S. THE
AREA OF RAIN THAT WAS OVER PARTS OF NORTH MISSISSIPPI THIS MORNING
HAS PUSHED SOUTH. COLD FRONT CURRENTLY EXTENDS FROM EASTERN OHIO
THROUGH SOUTHEAST MISSOURI AND INTO THE TEXAS PANHANDLE. A COUPLE
OF THUNDERSTORMS HAVE DEVELOPED AHEAD OF THE FRONT OVER WESTERN
KENTUCKY AND ARE TRACKING SOUTHEAST TOWARD THE FORECAST AREA.
THE COLD FRONT WILL CONTINUE TO TRACK SOUTHEAST TONIGHT WITH SOME
ADDITIONAL SCATTERED THUNDERSTORMS EXPECTED TO DEVELOP AHEAD OF
THE FRONT. THE FRONT WILL STILL BE OVER NORTH MISSISSIPPI FRIDAY
MORNING SO SOME ADDITIONAL SCATTERED THUNDERSTORMS WILL BE
POSSIBLE MAINLY OVER AREA SOUTH OF INTERSTATE 40. BEHIND THE FRONT
COOLER AND DRIER AIR WILL FILTER INTO THE REGION. TEMPERATURES
WILL BE MUCH COOLER WITH HIGHS ONLY IN THE 80S TO AROUND 90.
BY FRIDAY NIGHT...THE FRONT WILL BE WELL SOUTH OF THE REGION
ENDING THE THREAT OF RAIN. WITH DRIER AIR IN PLACE TEMPERATURES
WILL COOL OFF SOME WITH SOME LOCATIONS IN WEST TENNESSEE DROPPING
BELOW 60 DEGREES BY SATURDAY MORNING. THE WEEKEND LOOKS TO BE
QUITE PLEASANT AS HIGH PRESSURE REMAINS IN PLACE. DRY WEATHER WILL
CONTINUE FOR BOTH SATURDAY AND SUNDAY WITH TEMPERATURES MAINLY
BELOW NORMAL BOTH DAYS.
BY MONDAY...A WEAK COLD FRONT WILL BE APPROACHING THE REGION WITH
SOME SCATTERED THUNDERSTORMS POSSIBLE AHEAD OF THE FRONT. THE
FRONT WILL CONTINUE TO MOVE SLOWLY SOUTHEAST MONDAY NIGHT AND
TUESDAY WITH MORE SCATTERED THUNDERSTORMS POSSIBLE FROM MONDAY
NIGHT THROUGH TUESDAY NIGHT.
HIGH PRESSURE WILL BRIEFLY BUILD INTO THE REGION ON WEDNESDAY
BRINGING A BRIEF END TO THE THREAT OF RAIN. BY WEDNESDAY NIGHT THE
COLD FRONT WILL LIFT BACK NORTH AS A WARM FRONT BRINGING A CHANCE
OF MORE THUNDERSTORMS FOR WEDNESDAY NIGHT AND MUCH OF THURSDAY.
ARS
&&
.AVIATION...
00Z TAF SET
COLD FRONT STILL LOCATED BACK TO THE NORTHWEST BUT LOWER DEWPOINTS
HAVE WORKED INTO MUCH OF THE CWA THUS BEGINNING TO HAVE DOUBTS ON TSRA
DEVELOPMENT THIS EVENING ALONG THE FRONT. LATEST HRRR RUN DOESN/T
SHOW ANYTHING DEVELOPING AND THE NEW NAM SHOWS STUFF DEVELOPING
NOT UNTIL THE FRONT IS SOUTH AND EAST OF MEMPHIS. FOR NOW WILL
REMOVE MENTION OF VCTS AT KJBR BUT WILL LEAVE VCTS WORDING AT
OTHER TAF SITES. SOUTHWEST WINDS AROUND 8-10 KTS WITH HIGHER GUSTS
AT TIMES EXPECTED AHEAD OF THE FRONT. WINDS WILL SWITCH TO THE
NORTHWEST AND EVENTUALLY TO THE NORTH BEHIND THE FRONT.
KRM
&&
&&
.PRELIMINARY POINT TEMPS/POPS...
MEM 74 87 67 88 / 30 20 10 0
MKL 69 84 59 86 / 40 20 0 0
JBR 71 87 64 89 / 20 10 0 0
TUP 72 89 65 88 / 40 30 10 0
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
MO...NONE.
MS...NONE.
TN...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
602 PM CDT THU AUG 9 2012
.UPDATE...
NOT IMPRESSED WITH THE CHANCES FOR CONVECTION OVERNIGHT. ONLY
BULLISH TRENDS I SEE ARE WITH THE WRF AND THE FROPA WHICH IS
EXPECTED AT 12Z. OTW...UPPER DYNAMICS LOOKING WEAK WITH AN OVERALL
DECREASE IN MOISTURE DEPTH FROM 00Z TO 06Z. HRRR SHOWS ZILCH
THROUGH 6Z AND UPPER DIVERGENCE QUITE WEAK THROUGH 12Z ON THE GFS
AND NAM. I WILL GO AHEAD AND UPDATE GRIDS AD KNOCK POPS DOWN
PRIOR TO 06Z. AFT 06Z...WILL KEEP THE LIKELY POPS GOING ACROSS THE
NORTH BUT THIS MAY NEED A DOWNWARD YANK AS WELL LATER IN THIS
SHIFT.
REMAINDER OF FCST LOOKS TO BE IN GOOD SHAPE. NO MENTION OF FOG
CURRENTLY AND I SEE NO REASON TO ADD ANY AS TOVERS REMAIN NEAR TO
ABOVE 0. MIN TEMP FCST LOOKS TO BE IN GOOD SHAPE. UPDATE OUT SHORTLY.
&&
.PREV DISCUSSION... /ISSUED 340 PM CDT THU AUG 9 2012/
SHORT TERM...SHOWERS AND CLOUDS THAT STILL LINGERED ALONG THE
CUMBERLAND PLATEAU AT MID-AFTERNOON WERE HELPING TO PRODUCE A
SIGNIFICANT TEMPERATURE GRADIENT ACROSS THE MID STATE. AT 300
PM...TEMPERATURES RANGED FROM THE UPPER 60S AT CSV TO THE UPPER
80S OVER OUR MOST WESTERN COUNTIES.
WITH SHOWERS DEPARTING OUR AREA, FROM THE PLATEAU, WE NOW TURN OUR
EYES TO THE WEST, WHERE NEW THUNDERSTORMS WERE POPPING UP IN THE
AFTERNOON HEAT, OVER SOUTHWESTERN KENTUCKY. THESE STORMS WERE ALSO
OCCURRING ALONG THE EDGE OF A BAND OF MID-T0-UPPER LEVEL DRYING
THAT EXTENDED FROM SOUTHERN PARTS OF INDIANA AND ILLINOIS, ACROSS
SOUTHEAST MISSOURI INTO CENTRAL ARKANSAS. WITH THE POSSIBILITY OF
DRY AIR ENTRAINMENT AT THE MID LEVELS, EXPECT SOME GUSTY
DOWNBURSTS TO BE POSSIBLE WITH THESE STORMS AS THEY ADVANCE INTO
NORTHWESTERN MIDDLE TENNESSEE LATE THIS AFTERNOON AND EVENING.
AFTER THE INITIAL CONVECTION THIS EVENING, THAT DEVELOPS MAINLY
OVER THE NORTHWEST, BELIEVE WE WILL SEE MORE THUNDERSTORM
DEVELOPMENT LATER TONIGHT, AS UPPER TROUGH DEEPENS OVER THE OHIO
RIVER VALLEY, ENERGIZING THE SLEEPY STATIONARY FRONT JUST WEST OF
PADUCAH, AND BRINGING IT EASTWARD AS A COLD FRONT.
EXPECT THE COLD FRONT TO BE NEAR A BWG-BNA-WAYNESBORO LINE BY 12Z
FRIDAY, PUSHING TO NR A MSL-LIVINGSTON LINE BY 18Z, AND OFF THE
CUMBERLAND PLATEAU BY LATE FRIDAY AFTERNOON.
SPC HAS ALL OF OUR AREA IN A SLIGHT RISK FOR SEVERE THUNDERSTORMS
THROUGH 12Z FRIDAY, AS THE FRONT PUSHES IN, AND EXPECT TO SEE
SIMILAR STORMS TO THE ONES WE HAD THIS MORNING...VERY WET AND
JUICY (WITH TORRENTIAL DOWNPOURS) ALONG WITH THE POSSIBILITY FOR
STRONG, GUSTY DOWNBURST WINDS.
EXPECT SHOWERS AND STORMS TO FINALLY PUSH EAST OF THE MID STATE FRIDAY
EVENING, WITH SEVERAL DAYS OF DRY AND AUTUMN-LIKE CONDITIONS TO
FOLLOW OVER THE WEEKEND. EXPECT AFTERNOON DEW POINTS IN THE 50S
BOTH SATURDAY AND SUNDAY, WITH DAYTIME HIGHS MAINLY IN THE MIDDLE
80S. MANY PLACES WILL LIKELY SEE LOW TEMPERATURES DROP INTO THE
MID TO UPPER 50S SUNDAY MORNING.
LONG TERM...AFTER OUR DRY SPELL OVER THE WEEKEND, EXPECT
NORTHWEST FLOW TO BECOME MORE ZONAL, WITH TWO OR THREE UPPER LEVEL
SHORTWAVES LIKELY TO TRAVERSE THE AREA NEXT WEEK. THE TIMING OF
THESE IMPULSES, OF COURSE, IS VERY DIFFICULT. IT`S ALSO DIFFICULT
TO KNOW HOW MUCH SHRA/TSRA ACTIVITY EACH ONE WITH BRING WITH IT.
THEREFORE, HAVE PAINTED POPS WITH A BROAD BRUSH FOR MOST OF NEXT
WEEK, WITH A 20% POP MAKING REPEATED ONSTAGE APPEARANCES.
TEMPERATURES WILL WARM BACK TO AROUND 90 DEGREES OR IN THE LOWER
90S FOR AREAS WEST OF THE CUMBERLAND PLATEAU, WITH TEMPS FORECAST
TO BE MAINLY IN THE MIDDLE 80S ALONG THE PLATEAU ITSELF.
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
21
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
359 PM CDT WED AUG 8 2012
.SHORT TERM...
SHOWERS AND THUNDERSTORMS ARE DEVELOPING ACROSS THE HEARTLAND
AND CONCHO VALLEY THIS AFTERNOON. THIS ACTIVITY IS DEVELOPING
IN ASSOCIATION WITH LIFT FROM A WEAK SHORT WAVE THAT IS
OVERSPREADING THE AREA FROM THE NORTH. LATEST HRRR SEEMS TO BE
DOING A DECENT JOB SO FAR AND INDICATES ADDITIONAL DEVELOPMENT
ACROSS THE SOUTHERN HALF OF THE FORECAST AREA THROUGH EARLY EVENING.
WILL MAINTAIN 30 POPS SOUTH AND SLIGHT CHANCE POPS NORTH ACROSS
THE BIG COUNTRY THROUGH THE EVENING HOURS. MAY STILL SEE SOME
LINGERING ACTIVITY ALONG THE I-10 CORRIDOR THROUGH LATE EVENING
BUT MOST OF THE CONVECTION SHOULD DISSIPATE AFTER SUNEST. THE MAIN
THREAT FROM THUNDERSTORMS WILL BE LOCALLY HEAVY RAINFALL...GUSTY
WINDS AND DANGEROUS CLOUD TO GROUND LIGHTNING.
DRIER AIR WILL FILTER INTO THE AREA FROM THE NORTH LATER TONIGHT AND
THURSDAY. THIS WILL RESULT IN DRY AND HOT CONDITIONS ACROSS THE AREA
WITH AFTERNOON HIGHS AROUND THE CENTURY MARK. CANNOT RULE OUT AN
ISOLATED STORM OR TWO ACROSS SOUTHEAST SECTIONS THURSDAY AFTERNOON
SO KEPT ISOLATED MENTION OVER THIS AREA.
.LONG TERM...
AS AN UPPER TROUGH AND LOW DROP SOUTHEAST ACROSS THE LOWER
GREAT LAKES REGION...TRAILING PORTION OF ASSOCIATED COLD
FRONT WILL MOVE SOUTH INTO THE BIG COUNTRY THURSDAY NIGHT...
AND ACROSS THE REST OF WEST CENTRAL TEXAS ON FRIDAY. THIS
PORTION OF THE FRONT WILL BE WEAK HOWEVER...WITH THE MAIN
ADVECTION OF COOLER AIR EXPECTED TO BE TO THE NORTHEAST OF
OUR AREA. WITH WEAK SURFACE CONVERGENCE AND A DRIER AIRMASS
PROGGED...RAIN CHANCES LOOK LOOK TOO SMALL INCLUDE IN OUR AREA
WITH THE ARRIVAL/PASSAGE OF THIS FRONT. TEMPERATURES WILL BE
SLIGHTLY COOLER ACROSS THE BIG COUNTRY...WHERE HIGHS FRIDAY
ARE EXPECTED TO BE IN THE MID/UPPER 90S.
THE UPPER HIGH WILL BE CENTERED OVER NEW MEXICO DURING THE
WEEKEND. GIVEN ITS PROXIMITY...HOT AND DRY CONDITIONS CAN BE
EXPECTED FOR WEST CENTRAL TEXAS. THE WARMEST READINGS ARE
EXPECTED SUNDAY...WHEN HIGHS SHOULD RANGE FROM 100-105 DEGREES
AREAWIDE. LITTLE CHANGE IS INDICATED WITH THIS PATTERN THROUGH AT
LEAST EARLY NEXT WEEK. THE 12Z GFS AND ECMWF SHOW A WEAKENING WITH
THIS HIGH BY NEXT TUESDAY OR WEDNESDAY...WITH THE GFS BRINGING A
DISTURBANCE NORTH-NORTHEAST FROM THE LOWER RIO GRANDE VALLEY INTO
CENTRAL AND EASTERN TEXAS. GIVEN THAT THIS IS LATE DAY 6 AND DAY
7...LEANING AT THIS TIME TOWARD PERSISTENCE WITH THE FORECAST.
&&
.PRELIMINARY POINT TEMPS/POPS...
ABILENE 74 101 72 97 70 / 20 10 10 5 5
SAN ANGELO 74 101 73 101 70 / 30 20 10 10 5
JUNCTION 73 97 72 101 70 / 30 20 10 10 5
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
24/19
AREA FORECAST DISCUSSION...UPDATED
NWS SAN ANGELO TX
212 PM CDT WED AUG 8 2012
.UPDATE...
MADE A QUICK UPDATE TO THE FORECAST FOR THIS AFTERNOON AND
EVENING TO INCREASE POPS TO 30 PERCENT ACROSS THE SOUTHERN
HALF OF THE FORECAST AREA.
&&
.DISCUSSION...
SEVERAL WEAK OUTFLOW BOUNDARIES LEFT OVER FROM LAST NIGHT
WILL LINGER ACROSS THE AREA AND WILL BE A FOCUS FOR CONVECTIVE
DEVELOPMENT THIS AFTERNOON. LIFT WILL ALSO INCREASE ACROSS THE
AREA THIS AFTERNOON AS A WEAK SHORT WAVE DROPS SOUTH FROM
NORTHWEST TEXAS. LATEST HRRR SHOWS CONVECTION DEVELOPING ACROSS
THE HEARTLAND AND CONCHO VALLEY BY 20Z AND ALREADY STARTING TO
SEE SOME NEW CELLS DEVELOP OVER BROWN AND COLEMAN COUNTIES.
LATEST NAM/RUC ALSO INDICATING CONVECTIVE DEVELOPMENT IN A
SIMILAR FASHION. CONFIDENCE HAS INCREASED TO RAISE POPS TO 30
PERCENT ACROSS THE SOUTHERN TWO THIRDS OF THE CWA THROUGH THE
EVENING HOURS....WITH CONVECTION DIMINISHING LATER THIS EVENING.
UPDATED PRODUCTS WERE SENT.
&&
.PREV DISCUSSION... /ISSUED 1255 PM CDT WED AUG 8 2012/
DISCUSSION...
SEE 18Z AVIATION DISCUSSION BELOW.
AVIATION...
MAIN CHALLENGE THIS FORECAST CYCLE WILL BE CONVECTIVE CHANCES
ACROSS THE SOUTHERN TAF SITES THIS AFTERNOON. EXPECT PREDOMINANTLY
VFR FOR THE TERMINALS THE NEXT 24 HOURS BUT SCATTERED CONVECTION
IS EXPECTED TO DEVELOP MAINLY SOUTH OF THE KABI TERMINAL AFTER
20Z. INCLUDED VCTS FOR ALL TERMINALS EXCEPT KABI THIS AFTERNOON
UNTIL 01Z. VISIBILITY AND CIGS WILL BE LOWER WITH ANY CONVECTION
THAT OCCURS AND WILL MAKE NECESSARY AMENDMENTS IF NEEDED. LIGHT
WINDS WILL CONTINUE THE NEXT 24 HOURS WITH SPEEDS AT OR BELOW 10
KT.
PREV DISCUSSION... /ISSUED 623 AM CDT WED AUG 8 2012/
DISCUSSION...
AVIATION DISCUSSION FOLLOWS.
AVIATION...
ISOLATED SHOWERS AND THUNDERSTORMS MAY THREATEN THE KABI...
KSJT...AND KBBD TERMINALS THROUGH TODAY. A NIGHT TIME COMPLEX OF
STORMS MAY APPROACH THE KABI TERMINAL TONIGHT AFTER MIDNIGHT AND
BRING GUSTY NORTH WINDS OF 30 TO 40KTS. STRONG DOWNBURST WINDS IN
EXCESS OF 45KTS MIGHT ACCOMPANY ANY OF THE STORMS THAT DEVELOP THIS
AFTERNOON AND EVENING. HAVE LEFT OUT MENTION OF WINDS AND TSTORMS
IN TAF BECAUSE OF THEIR ISOLATED NATURE.
SATELLITE SHOWS A MESOSCALE CONVECTIVE VORTEX NEAR HASKELL THAT WAS
SLIDING SOUTH AND WAS PRODUCING A FEW SHOWERS. SHOWERS OR
THUNDERSTORMS COULD FORM NEAR THIS FEATURE AS IT TRACKS SOUTH.
PREV DISCUSSION... /ISSUED 338 AM CDT WED AUG 8 2012/
SHORT TERM...
IMPACTS...GUSTY NORTH WINDS 20 TO 25 MPH...AND ISOLATED LIGHTNING
STRIKES THROUGH 9 AM NORTH OF A LINE FROM MARY NEAL TO CROSS
PLAINS. ISOLATED DAMAGING WIND GUSTS AND CLOUD TO GROUND LIGHTNING
STRIKES THIS AFTERNOON ANYWHERE IN WEST CENTRAL TEXAS. GUSTY NORTH
WINDS OF 35 TO 45 MPH AGAIN TONIGHT MAINLY NORTH OF I20. HOT
TEMPERATURES ABOVE 100 ACROSS A LARGE PART OF THE WEST CENTRAL
TEXAS.
DISCUSSION...AT 08Z...THE LEADING EDGE OF AN OUTFLOW BOUNDARY
STRETCHED FROM ROBY TO ANSON TO ALBANY AND WAS MOVING SOUTH NEAR 30
MPH. BASED ON THE WEST TEXAS MESONET DATA...WIND GUSTED TO NEAR 39
MPH AT HASKELL AT 0720Z. MOSTLY SHOWERS AND AN ISOLATED
THUNDERSTORM CONTINUED TO DEVELOP BEHIND THE BOUNDARY. THE DIURNAL
LOW LEVEL JET OF 25 TO 30 KTS ALONG WITH HIGHER DIURNAL CAPE VALUES
NEAR 1000 J/KG WERE SUSTAINING THESE STORMS BEHIND THE BOUNDARY.
DECIDED TO GO WITH THE HIGHEST POPS NEAR 25 PERCENT ALONG AND NORTH
OF INTERSTATE 20 AND THEN 20 POPS SOUTH OF I20.
THIS COMPLEX OF STORMS SHOULD CONTINUE BEFORE DIMINISHING AROUND
900 AM AS THE LOW LEVEL JET WEAKENS. THE AFOREMENTIONED OUTFLOW
BOUNDARY MAY ALSO SERVE AS A TRIGGER FOR THUNDERSTORMS TO FORM THIS
AFTERNOON. CONTINUED 20 POPS FOR MOST OF THE AREA TODAY. WENT WITH
HOTTEST TEMPERATURES ACROSS THE SOUTH AND SLIGHTLY COOLER IN THE
RAIN COOLED AIR TO THE NORTH.
EXPECT A REPEAT PERFORMANCE LATE TONIGHT AS SHOWERS AND
THUNDERSTORMS DEVELOP IN THE NORTHWEST FLOW ACROSS THE TEXAS
PANHANDLE AND THEN MOVE SOUTH DURING THE NIGHT. FOR TONIGHT...WENT
WITH CHC POPS ACROSS THE BIG COUNTRY AND 20 POPS SOUTH.
LONG TERM...
MODELS HAVE THE 500MB HIGH CENTERED OVER THE FOUR CORNERS AREA
THURSDAY MORNING WITH THE NAM MOVING A SHORT WAVE DISTURBANCE
EMBEDDED IN THE NORTHERN FLOW ALOFT SOUTH THROUGH THE FORECAST
AREA DURING THE ON THURSDAY. THE NAM THEN MOVES A WEAK COLD FRONT
THROUGH THE AREA DURING THE DAY ON FRIDAY. THE GFS BRINGS THE COLD
FRONT THROUGH THE CWA EARLIER...DURING THE DAY ON THURSDAY. WILL
CONTINUE THE SLIGHT CHANCE OF SHOWERS AND THUNDERSTORMS DURING THE
DAY ON THURSDAY AND INTO THURSDAY EVENING.
SHOULD SEE FRIDAY AND SATURDAY AFTERNOON HIGHS A DEGREE
OR TWO COOLER IN THE WAKE OF THE COLD FRONT. THE UPPER HIGH WILL
BUILD EAST FOR THE REMAINDER OF THE EXTENDED WITH AFTERNOON HIGHS
WARMING A FEW DEGREES BEGINNING SUNDAY. WITH THE EXPANDING UPPER RIDGE
OVER THE FORECAST...THE OUTLOOK THROUGH THE REMAINDER OF THE
EXTENDED WILL BE HOT AN DRY.
&&
.PRELIMINARY POINT TEMPS/POPS...
ABILENE 99 75 100 72 97 / 20 20 10 10 5
SAN ANGELO 101 75 102 73 101 / 30 30 20 20 10
JUNCTION 102 74 103 72 101 / 20 30 20 20 10
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
99/99
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
100 PM EDT WED AUG 8 2012
.SYNOPSIS...
A STATIONARY FRONT ACROSS THE MOUNTAINS WILL GRADUALLY DISSIPATE
TODAY AS WEAK HIGH PRESSURE SLIDES EAST INTO THE REGION BY TONIGHT
BEFORE WEAKENING ON THURSDAY. A STRONG COLD FRONT WILL SWEEP
ACROSS THE REGION FRIDAY INTO FRIDAY EVENING...BRINGING ANOTHER
ROUND OF SHOWERS AND STORMS...SOME POTENTIALLY STRONG. COOLER AND
DRIER WEATHER IS EXPECTED BEHIND THE FRONT OVER THE WEEKEND INTO
EARLY NEXT WEEK AS HIGH PRESSURE BUILDS INTO THE REGION.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1255 PM ED WEDNESDAY...
ISOALTED TO SCATTERED SHOWERS AND STORMS HAVE DEVELOPED OVER THE
PAST 30 MINUTES GENERALLY ALONG AND EAST OF A LINE FROM WILKES
COUNTY NC TO APPOMATTOX COUNTY VA. ANTICIPATE THIS AREA TO BE THE
FOCUS FOR ADDITIONAL SHOWERS AND STORMS AS THE AFTERNOON
PROGRESSES. CANNOT RULE OUT VERY ISOLATED COVERAGE WEST OF THIS
REGION. HAVE MADE ADJUSTMENTS TO THE HOURLY TEMPERATURE...DEW
POINT...WINDS AND SKY COVER BASED UPON THE CURRENT OBSERVATIONS
AND EXPECTED TRENDS THIS AFTERNOON. THIS PROMPTED AN INCREASE IN
THE FORECAST HIGH TEMPERATURES BY TWO TO THREE DEGREES ACROSS THE
VIRGINIA PIEDMONT.
AS OF 952 AM EDT WEDNESDAY...
SURFACE OBSERVATIONS AND VISIBLE SATELLITE IMAGERY INDICATES A FEW
POCKETS OF LINGERING FOG IN SOME OF THE MOUNTAIN VALLEYS.
HOWEVER...ANTICIPATE THAT BY 1100 AM EDT...MOST OR ALL OF THIS
LINGERING FOG WILL HAVE DISSIPATED. PRECIPITATION HAS BEEN LIMITED
TO JUST A FEW ISOLATED SHOWERS ACROSS PARTS OF BUCKINGHAM COUNTY
VIRGINIA. ANTICIPATE LIMITED...IF ANY COVERAGE...THROUGH NOON
BEFORE COVERAGE INCREASES NEAR THE NC/VA BORDER. NO OTHER
SIGNIFICANT CHANGES. THE HOURLY TEMPERATURE...DEW POINT...WIND AND
SKY COVER GRIDS HAVE BEEN TWEAKED TO REFLECT THE LATEST
OBSERVATIONS AND EXPECTED TRENDS INTO THE EARLY AFTERNOON.
AS OF 230 AM EDT WEDNESDAY...
WEAK SURFACE BOUNDARY ACROSS THE MOUNTAINS WILL GRADUALLY
FADE TODAY AS A MID LEVEL WAVE PASSES TO THE EAST BY AFTERNOON AND
DRIER AIR ALOFT PER VAPOR LOOP ADVECTS IN FROM THE NW. HOWEVER THE
LOW LEVELS WILL REMAIN RATHER MOIST AND GIVEN ANOTHER SUBTLE S/W
PUSHING ACROSS THE WEST LATER ON CANT TOTALLY RULE OUT ADDED
ISOLATED CONVECTION...ESPCLY BLUE RIDGE AND POINTS EAST...MAINLY
SOUTH OF HIGHWAY 460 WHERE BOUNDARY LAYER MOISTURE/INSTABILITY
WILL BE BETTER. LATEST LOCAL GUIDANCE AS WELL AS THE SPC WRF AND
GFS HINT AT THIS WITH A FEW TSRA CLUSTERS DEVELOPING SW SECTIONS
ALONG THE BLUE RIDGE PER DIFF HEATING UNDER WEAK THETA-E
RIDGING...AND THEN OUT EAST JUST AHEAD OF WHAT WAS LEFT OF THE
OLD FRONT. AGAIN GIVEN WEAK STEERING AND LOCAL CONVERGENCE/OUTFLOW
COULD ALLOW FOR STORMS TO POP UP AND DUMP HEAVY RAINFALL BUT NOT
THINKING MUCH MORE COVERAGE THAN CHANCE TO ISOLATED POPS TODAY.
OTRW EXPECTING A GRADUAL RETURN TO MORE SUNSHINE AS THE HIGH/MID
LEVEL CLOUD DECK ERODES AND SHIFTS NE WITH THE PASSAGE OF THE WAVE
TO THE EAST THIS MORNING. THINK CLOUDS WILL LIMIT FOG FROM
BECOMING TOO WIDESPREAD EXCEPT PERHAPS THE FAR WEST SO WILL KEEP
MENTION PENDING RELEASE COVERAGE. WARM START AND SLIGHT 85H
WARMING UNDER A WEAK WEST/NW TRAJECTORY ALOFT SHOULD PUSH TEMPS TO
AROUND 90 EAST AND WELL INTO THE 80S WEST SO BUMPED UP CLOSER TO
THE MAV VALUES TODAY.
ANY CONVECTION SHOULD QUICKLY FADE WITH LOSS OF HEATING THIS EVENING
GIVEN LACK OF SUPPORT...WITH MAINLY CLEAR SKIES AFTER MIDNIGHT AS WE
SLIDE IN BETWEEN THE DEEP MOISTURE LOBE TO THE SE AND THE NEXT
UPSTREAM 5H TROF. THUS WILL CARRY SOME ISOLATED EVENING POPS MAINLY
SOUTH/EAST THEN GO DRY WITH PERHAPS SOME PATCHY FOG UNDER WEAK HIGH
PRESSURE LATE. THIS SHOULD ALSO ALLOW LOW TEMPS TO DROP CLOSER TO
THE COOLER MAV FOR THE MOST PART WITH RANGE FROM AROUND 60 VALLEYS
TO UPPER 60S SE AND RIDGES.
&&
.SHORT TERM /THURSDAY THROUGH SATURDAY NIGHT/...
AS OF 430 AM EDT WEDNESDAY...
ACTIVE WEATHER WILL BEGIN THE SHORT TERM PERIODS AS THE UPPER FLOW
AMPLIFIES ACROSS THE U.S...FEATURING A DEEPENING NEGATIVELY TILTED
UPPER TROUGH FROM THE GREAT LAKES TOWARD THE MID-ATLANTIC THU-FRI.
THE POPS AND SEVERE THREAT FOR THU SOMEWHAT QUESTIONABLE...BUT A
MORE DEFINITE POSSIBILITY FOR FRI AS THE ENTIRE SYSTEM SHIFTS ACROSS
THE CWA. NORMALLY SUCH A PATTERN WOULD SUGGEST A HIGH THREAT OF
SEVERE WX ACROSS THE REGION...ESPECIALLY FRI. HOWEVER...EXTENSIVE
CLOUD COVER AND MORNING SHRA FRI WILL LIKELY LIMIT HEATING...WITH
THE GREATER LIKELIHOOD FOR SEVERE PROBABLY FOCUSED ACROSS THE
PIEDMONT AND TOWARD THE COASTAL PLAIN FRI AFTERNOON/EVENING. AT THIS
POINT...HAVE ONLY MENTIONED GUSTY WINDS AND LOCALLY HEAVY RAIN. SPC
HAS OUTLOOKED THE WESTERN SECTIONS ON DAY2 AND THE ENTIRE CWA ON
DAY3...BUT AGAIN FEEL MAIN THREAT ON DAY3 SHOULD BE EAST OF THE BLUE
RIDGE. MODEL AND HPC QPF NOT OVERLY IMPRESSIVE AND INDICATIVE OF A
SKIP OVER EFFECT OF THE HEAVIEST PRECIPITATION AS AFOREMENTIONED
TOWARD EASTERN VA/NC. NONETHELESS...WITH FAIRLY WIDESPREAD HEAVY
RAIN ACROSS THE MOUNTAIN AREAS DURING THE PAST COUPLE OF
WEEKS...LATER SHIFTS WILL NEED TO EVALUATE THE ISSUANCE OF AN FFA
WEST OF THE BLUE RIDGE WHERE 1HR FFG VALUES GENERALLY LESS THAN 2
INCHES. WITH REFERENCE TO POP TIMING...ENOUGH FORCING APPEARS
EVIDENT COMBINED WITH PRE-SYSTEM HEATING TO SUPPORT GOOD CHC POPS
EAST TO LIKELY POPS WEST BY FRI EVENING. WILL HAVE LIKELY POPS TO
ALL AREAS FRI...WHICH MAY WELL BECOME CATEGORICAL WITH LATER
FORECASTS.
850MB TEMPS NEAR +20C ACROSS THE PIEDMONT REGION THU WILL STILL
SUPPORT WELL ABOVE NORMAL TEMPS IN THE LOW TO MID 90S EAST OF THE
BLUE RIDGE...WITH MOSTLY 80S TO THE WEST...EXCEPT 70S IN THE
MOUNTAINS ABOVE 3000 FT. EXTENSIVE CLOUD COVER AND SHRA/TSRA FRI
SHOULD HOLD TEMPS TO THE 70S IN THE MOUNTAINS TO 80S EAST OF THE
BLUE RIDGE.
LATEST MODELS HAVE COME INTO BETTER AGREEMENT IN PUSHING THE MAIN
UPPER TROUGH EAST OF THE REGION BY EARLY SAT...WHICH SHOULD TAKE THE
BULK OF THE PCPN WITH IT. HOWEVER...THE PARENT...RATHER DEEP UPPER
LOW FOR MID-AUGUST...WILL SWEEP THROUGH CENTRAL PA SAT AND COULD
PROMOTE ENOUGH LIFT IN UPSLOPE AREAS OF WV/N VA TO SUPPORT ISOLD
-SHRA DURING DAYTIME HEATING...THUS HAVE INCLUDED SLIGHT CHC POPS
ACCORDINGLY. 850MB TEMPS DROP TO THE LOWEST LEVELS SEEN IN OVER TWO
MONTHS...WITH +10C ACROSS ALL EXCEPT THE PIEDMONT BY 12Z SAT. THIS
SHOULD ALLOW FOR SOME RATHER REFRESHING HIGHS IN THE 70S WEST OF THE
BLUE RIDGE AND 80S EAST...WITH DEWPOINTS DROPPING INTO THE 50S WEST
OF THE BLUE RIDGE AND 60S ACROSS THE PIEDMONT.
&&
.LONG TERM /SUNDAY THROUGH TUESDAY/...
AS OF 430 AM EDT WEDNESDAY...
HAVE NOT MADE ANY SIGNIFICANT CHANGES TO THE LONG TERM AT THIS TIME.
IT APPEARS THAT A RATHER UNSETTLED WEATHER PATTERN WILL REMAIN IN
PLACE THROUGHOUT THE EXTENDED AS A SERIES OF NW FLOW DISTURBANCES
TRACK ACROSS THE REGION. THE ECMWF/GFS ARE AT ODDS WITH RESPECT TO
THE AMPLIFICATION OF THE NEXT UPPER TROUGH TOWARD THE MIDDLE OF NEXT
WEEK... WITH THE GFS FAVORING A FLATTER...MORE ZONAL FLOW. AT ANY
RATE...IT APPEARS THAT AT LEAST CHC POPS FOR SHRA/TSRA WILL CONTINUE
THROUGHOUT THE EXTENDED WITH TEMPS RETURNING BACK TO AOA NORMAL
LEVELS. LOW-LEVEL MOISTURE WILL ALSO BE INCREASING...RESULTING IN
INCREASINGLY MORE HUMID CONDITIONS AS WELL.
&&
.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
AS OF 645 AM EDT WEDNESDAY...
EXTENSIVE MID AND HIGH CLOUD CANOPY ASSOCIATED WITH WAVE/UPPER JET
CONTINUES TO SLOWLY PUSH EAST AND SHOULD EXIT THE AREA BY MID
MORNING IF NOT SOONER. MAY SEE A FEW ADDED SHRA DEVELOP OVER THE
SW THIS MORNING BUT MOSTLY SOUTH OF THE TAF SITES. OTRW FOG THE
MAIN CONCERN AGAIN EARLY THIS MORNING WITH AREAS OF IFR/LIFR IN
THE VALLEYS/ALONG THE WESTERN RIDGES...PRIMARILY KLWB/KBLF AND
KBCB IN THE WEST AND KLYH IN THE EAST. MAY STILL SEE A BRIEF
PERIOD OF MVFR IN FOG AT KDAN OTRW VFR AROUND KROA. SHOULD SEE
MOST OF THE FOG/STRATUS ERODE BY 14Z...10AM WITH ONLY KLWB LIKELY
HANGING ONTO POCKETS OF LOWER VSBYS A WHILE LONGER.
ONCE THE FOG FADES AND THE MID DECK EXITS SHOULD SEE MAINLY VFR
FOR MOST OF THE DAY WITH SCTD-BKN 4-6K FT CU FIELDS. ISOLATED
CONVECTION AGAIN POSSIBLE ESPCLY IN SPOTS ALONG THE BLUE RIDGE AND
OUT EAST SO INCLUDED A VCTS MENTION FROM KROA EAST BASED ON THE
LATEST HRRR MODEL WHICH SHOWS A FEW CLUSTERS DEVELOPING FROM NW NC
INTO THE VA PIEDMONT BY MID AFTERNOON. ELSW WILL LEAVE OUT FOR NOW
GIVEN ISOLATED NATURE. AGAIN EXPECT ANY STORMS TO DIMINISH WITH
LOSS OF HEATING FOLLOWED BY MAINLY CLEAR SKIES WITH ANOTHER ROUND
OF MVFR/IFR FOG ESPCLY VALLEYS GIVEN LESS CLOUD COVER OVERNIGHT.
PROXIMITY OF THE OLD FRONT AND TROPICAL AIRMASS JUST TO THE
SOUTH... WHICH WILL BEGIN A NORTHWARD RETURN BY LATE WEEK...WILL
MAINTAIN A DAILY THREAT FOR PATCHY FLIGHT RESTRICTIONS IN VICINITY
OF MAINLY DIURNALLY DRIVEN SHOWERS/STORMS FOR MUCH OF THE REST OF
THE WEEK...WITH A CONTINUED THREAT FOR RESTRICTIONS INTO THE
OVERNIGHT PERIODS WHERE FOG DEVELOPS. MORE WIDESPREAD SHRA/TSRA
LIKELY BY WEEKS END AHEAD OF A STRONGER COLD FRONT THAT LOOKS TO
DIVE THRU THE REGION FRIDAY INTO FRIDAY NIGHT. IMPROVING
CONDITIONS TO VFR LIKELY BEHIND THE FRONT ESPCLY ACROSS THE EAST
FOR THE WEEKEND.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...JH
NEAR TERM...DS/JH
SHORT TERM...RAB
LONG TERM...PH/RAB
AVIATION...DS/JH/KM
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
957 AM EDT WED AUG 8 2012
.SYNOPSIS...
A STATIONARY FRONT ACROSS THE MOUNTAINS WILL GRADUALLY DISSIPATE
TODAY AS WEAK HIGH PRESSURE SLIDES EAST INTO THE REGION BY TONIGHT
BEFORE WEAKENING ON THURSDAY. A STRONG COLD FRONT WILL SWEEP
ACROSS THE REGION FRIDAY INTO FRIDAY EVENING...BRINGING ANOTHER
ROUND OF SHOWERS AND STORMS...SOME POTENTIALLY STRONG. COOLER AND
DRIER WEATHER IS EXPECTED BEHIND THE FRONT OVER THE WEEKEND INTO
EARLY NEXT WEEK AS HIGH PRESSURE BUILDS INTO THE REGION.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 952 AM EDT WEDNESDAY...
SURFACE OBSERVATIONS AND VISIBLE SATELLITE IMAGERY INDICATES A FEW
POCKETS OF LINGERING FOG IN SOME OF THE MOUNTAIN VALLEYS.
HOWEVER...ANTICIPATE THAT BY 1100 AM EDT...MOST OR ALL OF THIS
LINGERING FOG WILL HAVE DISSIPATED. PRECIPITATION HAS BEEN LIMITED
TO JUST A FEW ISOLATED SHOWERS ACROSS PARTS OF BUCKINGHAM COUNTY
VIRGINIA. ANTICIPATE LIMITED...IF ANY COVERAGE...THROUGH NOON
BEFORE COVERAGE INCREASES NEAR THE NC/VA BORDER. NO OTHER
SIGNIFICANT CHANGES. THE HOURLY TEMPERATURE...DEW POINT...WIND AND
SKY COVER GRIDS HAVE BEEN TWEAKED TO REFLECT THE LATEST
OBSERVATIONS AND EXPECTED TRENDS INTO THE EARLY AFTERNOON.
AS OF 230 AM EDT WEDNESDAY...
WEAK SURFACE BOUNDARY ACROSS THE MOUNTAINS WILL GRADUALLY
FADE TODAY AS A MID LEVEL WAVE PASSES TO THE EAST BY AFTERNOON AND
DRIER AIR ALOFT PER VAPOR LOOP ADVECTS IN FROM THE NW. HOWEVER THE
LOW LEVELS WILL REMAIN RATHER MOIST AND GIVEN ANOTHER SUBTLE S/W
PUSHING ACROSS THE WEST LATER ON CANT TOTALLY RULE OUT ADDED
ISOLATED CONVECTION...ESPCLY BLUE RIDGE AND POINTS EAST...MAINLY
SOUTH OF HIGHWAY 460 WHERE BOUNDARY LAYER MOISTURE/INSTABILITY
WILL BE BETTER. LATEST LOCAL GUIDANCE AS WELL AS THE SPC WRF AND
GFS HINT AT THIS WITH A FEW TSRA CLUSTERS DEVELOPING SW SECTIONS
ALONG THE BLUE RIDGE PER DIFF HEATING UNDER WEAK THETA-E
RIDGING...AND THEN OUT EAST JUST AHEAD OF WHAT WAS LEFT OF THE
OLD FRONT. AGAIN GIVEN WEAK STEERING AND LOCAL CONVERGENCE/OUTFLOW
COULD ALLOW FOR STORMS TO POP UP AND DUMP HEAVY RAINFALL BUT NOT
THINKING MUCH MORE COVERAGE THAN CHANCE TO ISOLATED POPS TODAY.
OTRW EXPECTING A GRADUAL RETURN TO MORE SUNSHINE AS THE HIGH/MID
LEVEL CLOUD DECK ERODES AND SHIFTS NE WITH THE PASSAGE OF THE WAVE
TO THE EAST THIS MORNING. THINK CLOUDS WILL LIMIT FOG FROM
BECOMING TOO WIDESPREAD EXCEPT PERHAPS THE FAR WEST SO WILL KEEP
MENTION PENDING RELEASE COVERAGE. WARM START AND SLIGHT 85H
WARMING UNDER A WEAK WEST/NW TRAJECTORY ALOFT SHOULD PUSH TEMPS TO
AROUND 90 EAST AND WELL INTO THE 80S WEST SO BUMPED UP CLOSER TO
THE MAV VALUES TODAY.
ANY CONVECTION SHOULD QUICKLY FADE WITH LOSS OF HEATING THIS EVENING
GIVEN LACK OF SUPPORT...WITH MAINLY CLEAR SKIES AFTER MIDNIGHT AS WE
SLIDE IN BETWEEN THE DEEP MOISTURE LOBE TO THE SE AND THE NEXT
UPSTREAM 5H TROF. THUS WILL CARRY SOME ISOLATED EVENING POPS MAINLY
SOUTH/EAST THEN GO DRY WITH PERHAPS SOME PATCHY FOG UNDER WEAK HIGH
PRESSURE LATE. THIS SHOULD ALSO ALLOW LOW TEMPS TO DROP CLOSER TO
THE COOLER MAV FOR THE MOST PART WITH RANGE FROM AROUND 60 VALLEYS
TO UPPER 60S SE AND RIDGES.
&&
.SHORT TERM /THURSDAY THROUGH SATURDAY NIGHT/...
AS OF 430 AM EDT WEDNESDAY...
ACTIVE WEATHER WILL BEGIN THE SHORT TERM PERIODS AS THE UPPER FLOW
AMPLIFIES ACROSS THE U.S...FEATURING A DEEPENING NEGATIVELY TILTED
UPPER TROUGH FROM THE GREAT LAKES TOWARD THE MID-ATLANTIC THU-FRI.
THE POPS AND SEVERE THREAT FOR THU SOMEWHAT QUESTIONABLE...BUT A
MORE DEFINITE POSSIBILITY FOR FRI AS THE ENTIRE SYSTEM SHIFTS ACROSS
THE CWA. NORMALLY SUCH A PATTERN WOULD SUGGEST A HIGH THREAT OF
SEVERE WX ACROSS THE REGION...ESPECIALLY FRI. HOWEVER...EXTENSIVE
CLOUD COVER AND MORNING SHRA FRI WILL LIKELY LIMIT HEATING...WITH
THE GREATER LIKELIHOOD FOR SEVERE PROBABLY FOCUSED ACROSS THE
PIEDMONT AND TOWARD THE COASTAL PLAIN FRI AFTERNOON/EVENING. AT THIS
POINT...HAVE ONLY MENTIONED GUSTY WINDS AND LOCALLY HEAVY RAIN. SPC
HAS OUTLOOKED THE WESTERN SECTIONS ON DAY2 AND THE ENTIRE CWA ON
DAY3...BUT AGAIN FEEL MAIN THREAT ON DAY3 SHOULD BE EAST OF THE BLUE
RIDGE. MODEL AND HPC QPF NOT OVERLY IMPRESSIVE AND INDICATIVE OF A
SKIP OVER EFFECT OF THE HEAVIEST PRECIPITATION AS AFOREMENTIONED
TOWARD EASTERN VA/NC. NONETHELESS...WITH FAIRLY WIDESPREAD HEAVY
RAIN ACROSS THE MOUNTAIN AREAS DURING THE PAST COUPLE OF
WEEKS...LATER SHIFTS WILL NEED TO EVALUATE THE ISSUANCE OF AN FFA
WEST OF THE BLUE RIDGE WHERE 1HR FFG VALUES GENERALLY LESS THAN 2
INCHES. WITH REFERENCE TO POP TIMING...ENOUGH FORCING APPEARS
EVIDENT COMBINED WITH PRE-SYSTEM HEATING TO SUPPORT GOOD CHC POPS
EAST TO LIKELY POPS WEST BY FRI EVENING. WILL HAVE LIKELY POPS TO
ALL AREAS FRI...WHICH MAY WELL BECOME CATEGORICAL WITH LATER
FORECASTS.
850MB TEMPS NEAR +20C ACROSS THE PIEDMONT REGION THU WILL STILL
SUPPORT WELL ABOVE NORMAL TEMPS IN THE LOW TO MID 90S EAST OF THE
BLUE RIDGE...WITH MOSTLY 80S TO THE WEST...EXCEPT 70S IN THE
MOUNTAINS ABOVE 3000 FT. EXTENSIVE CLOUD COVER AND SHRA/TSRA FRI
SHOULD HOLD TEMPS TO THE 70S IN THE MOUNTAINS TO 80S EAST OF THE
BLUE RIDGE.
LATEST MODELS HAVE COME INTO BETTER AGREEMENT IN PUSHING THE MAIN
UPPER TROUGH EAST OF THE REGION BY EARLY SAT...WHICH SHOULD TAKE THE
BULK OF THE PCPN WITH IT. HOWEVER...THE PARENT...RATHER DEEP UPPER
LOW FOR MID-AUGUST...WILL SWEEP THROUGH CENTRAL PA SAT AND COULD
PROMOTE ENOUGH LIFT IN UPSLOPE AREAS OF WV/N VA TO SUPPORT ISOLD
-SHRA DURING DAYTIME HEATING...THUS HAVE INCLUDED SLIGHT CHC POPS
ACCORDINGLY. 850MB TEMPS DROP TO THE LOWEST LEVELS SEEN IN OVER TWO
MONTHS...WITH +10C ACROSS ALL EXCEPT THE PIEDMONT BY 12Z SAT. THIS
SHOULD ALLOW FOR SOME RATHER REFRESHING HIGHS IN THE 70S WEST OF THE
BLUE RIDGE AND 80S EAST...WITH DEWPOINTS DROPPING INTO THE 50S WEST
OF THE BLUE RIDGE AND 60S ACROSS THE PIEDMONT.
&&
.LONG TERM /SUNDAY THROUGH TUESDAY/...
AS OF 430 AM EDT WEDNESDAY...
HAVE NOT MADE ANY SIGNIFICANT CHANGES TO THE LONG TERM AT THIS TIME.
IT APPEARS THAT A RATHER UNSETTLED WEATHER PATTERN WILL REMAIN IN
PLACE THROUGHOUT THE EXTENDED AS A SERIES OF NW FLOW DISTURBANCES
TRACK ACROSS THE REGION. THE ECMWF/GFS ARE AT ODDS WITH RESPECT TO
THE AMPLIFICATION OF THE NEXT UPPER TROUGH TOWARD THE MIDDLE OF NEXT
WEEK... WITH THE GFS FAVORING A FLATTER...MORE ZONAL FLOW. AT ANY
RATE...IT APPEARS THAT AT LEAST CHC POPS FOR SHRA/TSRA WILL CONTINUE
THROUGHOUT THE EXTENDED WITH TEMPS RETURNING BACK TO AOA NORMAL
LEVELS. LOW-LEVEL MOISTURE WILL ALSO BE INCREASING...RESULTING IN
INCREASINGLY MORE HUMID CONDITIONS AS WELL.
&&
.AVIATION /14Z WEDNESDAY THROUGH SUNDAY/...
AS OF 645 AM EDT WEDNESDAY...
EXTENSIVE MID AND HIGH CLOUD CANOPY ASSOCIATED WITH WAVE/UPPER JET
CONTINUES TO SLOWLY PUSH EAST AND SHOULD EXIT THE AREA BY MID
MORNING IF NOT SOONER. MAY SEE A FEW ADDED SHRA DEVELOP OVER THE
SW THIS MORNING BUT MOSTLY SOUTH OF THE TAF SITES. OTRW FOG THE
MAIN CONCERN AGAIN EARLY THIS MORNING WITH AREAS OF IFR/LIFR IN
THE VALLEYS/ALONG THE WESTERN RIDGES...PRIMARILY KLWB/KBLF AND
KBCB IN THE WEST AND KLYH IN THE EAST. MAY STILL SEE A BRIEF
PERIOD OF MVFR IN FOG AT KDAN OTRW VFR AROUND KROA. SHOULD SEE
MOST OF THE FOG/STRATUS ERODE BY 14Z...10AM WITH ONLY KLWB LIKELY
HANGING ONTO POCKETS OF LOWER VSBYS A WHILE LONGER.
ONCE THE FOG FADES AND THE MID DECK EXITS SHOULD SEE MAINLY VFR
FOR MOST OF THE DAY WITH SCTD-BKN 4-6K FT CU FIELDS. ISOLATED
CONVECTION AGAIN POSSIBLE ESPCLY IN SPOTS ALONG THE BLUE RIDGE AND
OUT EAST SO INCLUDED A VCTS MENTION FROM KROA EAST BASED ON THE
LATEST HRRR MODEL WHICH SHOWS A FEW CLUSTERS DEVELOPING FROM NW NC
INTO THE VA PIEDMONT BY MID AFTERNOON. ELSW WILL LEAVE OUT FOR NOW
GIVEN ISOLATED NATURE. AGAIN EXPECT ANY STORMS TO DIMINISH WITH
LOSS OF HEATING FOLLOWED BY MAINLY CLEAR SKIES WITH ANOTHER ROUND
OF MVFR/IFR FOG ESPCLY VALLEYS GIVEN LESS CLOUD COVER OVERNIGHT.
PROXIMITY OF THE OLD FRONT AND TROPICAL AIRMASS JUST TO THE
SOUTH... WHICH WILL BEGIN A NORTHWARD RETURN BY LATE WEEK...WILL
MAINTAIN A DAILY THREAT FOR PATCHY FLIGHT RESTRICTIONS IN VICINITY
OF MAINLY DIURNALLY DRIVEN SHOWERS/STORMS FOR MUCH OF THE REST OF
THE WEEK...WITH A CONTINUED THREAT FOR RESTRICTIONS INTO THE
OVERNIGHT PERIODS WHERE FOG DEVELOPS. MORE WIDESPREAD SHRA/TSRA
LIKELY BY WEEKS END AHEAD OF A STRONGER COLD FRONT THAT LOOKS TO
DIVE THRU THE REGION FRIDAY INTO FRIDAY NIGHT. IMPROVING
CONDITIONS TO VFR LIKELY BEHIND THE FRONT ESPCLY ACROSS THE EAST
FOR THE WEEKEND.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...JH
NEAR TERM...DS/JH
SHORT TERM...RAB
LONG TERM...PH/RAB
AVIATION...DS/JH/KM
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
731 AM EDT WED AUG 8 2012
.SYNOPSIS...
A STATIONARY FRONT ACROSS THE MOUNTAINS WILL GRADUALLY DISSIPATE
TODAY AS WEAK HIGH PRESSURE SLIDES EAST INTO THE REGION BY TONIGHT
BEFORE WEAKENING ON THURSDAY. A STRONG COLD FRONT WILL SWEEP
ACROSS THE REGION FRIDAY INTO FRIDAY EVENING...BRINGING ANOTHER
ROUND OF SHOWERS AND STORMS...SOME POTENTIALLY STRONG. COOLER AND
DRIER WEATHER IS EXPECTED BEHIND THE FRONT OVER THE WEEKEND INTO
EARLY NEXT WEEK AS HIGH PRESSURE BUILDS INTO THE REGION.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 230 AM EDT WEDNESDAY...
WEAK SURFACE BOUNDARY ACROSS THE MOUNTAINS WILL GRADUALLY
FADE TODAY AS A MID LEVEL WAVE PASSES TO THE EAST BY AFTERNOON AND
DRIER AIR ALOFT PER VAPOR LOOP ADVECTS IN FROM THE NW. HOWEVER THE
LOW LEVELS WILL REMAIN RATHER MOIST AND GIVEN ANOTHER SUBTLE S/W
PUSHING ACROSS THE WEST LATER ON CANT TOTALLY RULE OUT ADDED
ISOLATED CONVECTION...ESPCLY BLUE RIDGE AND POINTS EAST...MAINLY
SOUTH OF HIGHWAY 460 WHERE BOUNDARY LAYER MOISTURE/INSTABILITY
WILL BE BETTER. LATEST LOCAL GUIDANCE AS WELL AS THE SPC WRF AND
GFS HINT AT THIS WITH A FEW TSRA CLUSTERS DEVELOPING SW SECTIONS
ALONG THE BLUE RIDGE PER DIFF HEATING UNDER WEAK THETA-E
RIDGING...AND THEN OUT EAST JUST AHEAD OF WHAT WAS LEFT OF THE
OLD FRONT. AGAIN GIVEN WEAK STEERING AND LOCAL CONVERGENCE/OUTFLOW
COULD ALLOW FOR STORMS TO POP UP AND DUMP HEAVY RAINFALL BUT NOT
THINKING MUCH MORE COVERAGE THAN CHANCE TO ISOLATED POPS TODAY.
OTRW EXPECTING A GRADUAL RETURN TO MORE SUNSHINE AS THE HIGH/MID
LEVEL CLOUD DECK ERODES AND SHIFTS NE WITH THE PASSAGE OF THE WAVE
TO THE EAST THIS MORNING. THINK CLOUDS WILL LIMIT FOG FROM
BECOMING TOO WIDESPREAD EXCEPT PERHAPS THE FAR WEST SO WILL KEEP
MENTION PENDING RELEASE COVERAGE. WARM START AND SLIGHT 85H
WARMING UNDER A WEAK WEST/NW TRAJECTORY ALOFT SHOULD PUSH TEMPS TO
AROUND 90 EAST AND WELL INTO THE 80S WEST SO BUMPED UP CLOSER TO
THE MAV VALUES TODAY.
ANY CONVECTION SHOULD QUICKLY FADE WITH LOSS OF HEATING THIS EVENING
GIVEN LACK OF SUPPORT...WITH MAINLY CLEAR SKIES AFTER MIDNIGHT AS WE
SLIDE IN BETWEEN THE DEEP MOISTURE LOBE TO THE SE AND THE NEXT
UPSTREAM 5H TROF. THUS WILL CARRY SOME ISOLATED EVENING POPS MAINLY
SOUTH/EAST THEN GO DRY WITH PERHAPS SOME PATCHY FOG UNDER WEAK HIGH
PRESSURE LATE. THIS SHOULD ALSO ALLOW LOW TEMPS TO DROP CLOSER TO
THE COOLER MAV FOR THE MOST PART WITH RANGE FROM AROUND 60 VALLEYS
TO UPPER 60S SE AND RIDGES.
&&
.SHORT TERM /THURSDAY THROUGH SATURDAY NIGHT/...
AS OF 430 AM EDT WEDNESDAY...
ACTIVE WEATHER WILL BEGIN THE SHORT TERM PERIODS AS THE UPPER FLOW
AMPLIFIES ACROSS THE U.S...FEATURING A DEEPENING NEGATIVELY TILTED
UPPER TROUGH FROM THE GREAT LAKES TOWARD THE MID-ATLANTIC THU-FRI.
THE POPS AND SEVERE THREAT FOR THU SOMEWHAT QUESTIONABLE...BUT A
MORE DEFINITE POSSIBILITY FOR FRI AS THE ENTIRE SYSTEM SHIFTS ACROSS
THE CWA. NORMALLY SUCH A PATTERN WOULD SUGGEST A HIGH THREAT OF
SEVERE WX ACROSS THE REGION...ESPECIALLY FRI. HOWEVER...EXTENSIVE
CLOUD COVER AND MORNING SHRA FRI WILL LIKELY LIMIT HEATING...WITH
THE GREATER LIKELIHOOD FOR SEVERE PROBABLY FOCUSED ACROSS THE
PIEDMONT AND TOWARD THE COASTAL PLAIN FRI AFTERNOON/EVENING. AT THIS
POINT...HAVE ONLY MENTIONED GUSTY WINDS AND LOCALLY HEAVY RAIN. SPC
HAS OUTLOOKED THE WESTERN SECTIONS ON DAY2 AND THE ENTIRE CWA ON
DAY3...BUT AGAIN FEEL MAIN THREAT ON DAY3 SHOULD BE EAST OF THE BLUE
RIDGE. MODEL AND HPC QPF NOT OVERLY IMPRESSIVE AND INDICATIVE OF A
SKIP OVER EFFECT OF THE HEAVIEST PRECIPITATION AS AFOREMENTIONED
TOWARD EASTERN VA/NC. NONETHELESS...WITH FAIRLY WIDESPREAD HEAVY
RAIN ACROSS THE MOUNTAIN AREAS DURING THE PAST COUPLE OF
WEEKS...LATER SHIFTS WILL NEED TO EVALUATE THE ISSUANCE OF AN FFA
WEST OF THE BLUE RIDGE WHERE 1HR FFG VALUES GENERALLY LESS THAN 2
INCHES. WITH REFERENCE TO POP TIMING...ENOUGH FORCING APPEARS
EVIDENT COMBINED WITH PRE-SYSTEM HEATING TO SUPPORT GOOD CHC POPS
EAST TO LIKELY POPS WEST BY FRI EVENING. WILL HAVE LIKELY POPS TO
ALL AREAS FRI...WHICH MAY WELL BECOME CATEGORICAL WITH LATER
FORECASTS.
850MB TEMPS NEAR +20C ACROSS THE PIEDMONT REGION THU WILL STILL
SUPPORT WELL ABOVE NORMAL TEMPS IN THE LOW TO MID 90S EAST OF THE
BLUE RIDGE...WITH MOSTLY 80S TO THE WEST...EXCEPT 70S IN THE
MOUNTAINS ABOVE 3000 FT. EXTENSIVE CLOUD COVER AND SHRA/TSRA FRI
SHOULD HOLD TEMPS TO THE 70S IN THE MOUNTAINS TO 80S EAST OF THE
BLUE RIDGE.
LATEST MODELS HAVE COME INTO BETTER AGREEMENT IN PUSHING THE MAIN
UPPER TROUGH EAST OF THE REGION BY EARLY SAT...WHICH SHOULD TAKE THE
BULK OF THE PCPN WITH IT. HOWEVER...THE PARENT...RATHER DEEP UPPER
LOW FOR MID-AUGUST...WILL SWEEP THROUGH CENTRAL PA SAT AND COULD
PROMOTE ENOUGH LIFT IN UPSLOPE AREAS OF WV/N VA TO SUPPORT ISOLD
-SHRA DURING DAYTIME HEATING...THUS HAVE INCLUDED SLIGHT CHC POPS
ACCORDINGLY. 850MB TEMPS DROP TO THE LOWEST LEVELS SEEN IN OVER TWO
MONTHS...WITH +10C ACROSS ALL EXCEPT THE PIEDMONT BY 12Z SAT. THIS
SHOULD ALLOW FOR SOME RATHER REFRESHING HIGHS IN THE 70S WEST OF THE
BLUE RIDGE AND 80S EAST...WITH DEWPOINTS DROPPING INTO THE 50S WEST
OF THE BLUE RIDGE AND 60S ACROSS THE PIEDMONT.
&&
.LONG TERM /SUNDAY THROUGH TUESDAY/...
AS OF 430 AM EDT WEDNESDAY...
HAVE NOT MADE ANY SIGNIFICANT CHANGES TO THE LONG TERM AT THIS TIME.
IT APPEARS THAT A RATHER UNSETTLED WEATHER PATTERN WILL REMAIN IN
PLACE THROUGHOUT THE EXTENDED AS A SERIES OF NW FLOW DISTURBANCES
TRACK ACROSS THE REGION. THE ECMWF/GFS ARE AT ODDS WITH RESPECT TO
THE AMPLIFICATION OF THE NEXT UPPER TROUGH TOWARD THE MIDDLE OF NEXT
WEEK... WITH THE GFS FAVORING A FLATTER...MORE ZONAL FLOW. AT ANY
RATE...IT APPEARS THAT AT LEAST CHC POPS FOR SHRA/TSRA WILL CONTINUE
THROUGHOUT THE EXTENDED WITH TEMPS RETURNING BACK TO AOA NORMAL
LEVELS. LOW-LEVEL MOISTURE WILL ALSO BE INCREASING...RESULTING IN
INCREASINGLY MORE HUMID CONDITIONS AS WELL.
&&
.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
AS OF 645 AM EDT WEDNESDAY...
EXTENSIVE MID AND HIGH CLOUD CANOPY ASSOCIATED WITH WAVE/UPPER JET
CONTINUES TO SLOWLY PUSH EAST AND SHOULD EXIT THE AREA BY MID
MORNING IF NOT SOONER. MAY SEE A FEW ADDED SHRA DEVELOP OVER THE
SW THIS MORNING BUT MOSTLY SOUTH OF THE TAF SITES. OTRW FOG THE
MAIN CONCERN AGAIN EARLY THIS MORNING WITH AREAS OF IFR/LIFR IN
THE VALLEYS/ALONG THE WESTERN RIDGES...PRIMARILY KLWB/KBLF AND
KBCB IN THE WEST AND KLYH IN THE EAST. MAY STILL SEE A BRIEF
PERIOD OF MVFR IN FOG AT KDAN OTRW VFR AROUND KROA. SHOULD SEE
MOST OF THE FOG/STRATUS ERODE BY 14Z...10AM WITH ONLY KLWB LIKELY
HANGING ONTO POCKETS OF LOWER VSBYS A WHILE LONGER.
ONCE THE FOG FADES AND THE MID DECK EXITS SHOULD SEE MAINLY VFR
FOR MOST OF THE DAY WITH SCTD-BKN 4-6K FT CU FIELDS. ISOLATED
CONVECTION AGAIN POSSIBLE ESPCLY IN SPOTS ALONG THE BLUE RIDGE AND
OUT EAST SO INCLUDED A VCTS MENTION FROM KROA EAST BASED ON THE
LATEST HRRR MODEL WHICH SHOWS A FEW CLUSTERS DEVELOPING FROM NW NC
INTO THE VA PIEDMONT BY MID AFTERNOON. ELSW WILL LEAVE OUT FOR NOW
GIVEN ISOLATED NATURE. AGAIN EXPECT ANY STORMS TO DIMINISH WITH
LOSS OF HEATING FOLLOWED BY MAINLY CLEAR SKIES WITH ANOTHER ROUND
OF MVFR/IFR FOG ESPCLY VALLEYS GIVEN LESS CLOUD COVER OVERNIGHT.
PROXIMITY OF THE OLD FRONT AND TROPICAL AIRMASS JUST TO THE
SOUTH... WHICH WILL BEGIN A NORTHWARD RETURN BY LATE WEEK...WILL
MAINTAIN A DAILY THREAT FOR PATCHY FLIGHT RESTRICTIONS IN VICINITY
OF MAINLY DIURNALLY DRIVEN SHOWERS/STORMS FOR MUCH OF THE REST OF
THE WEEK...WITH A CONTINUED THREAT FOR RESTRICTIONS INTO THE
OVERNIGHT PERIODS WHERE FOG DEVELOPS. MORE WIDESPREAD SHRA/TSRA
LIKELY BY WEEKS END AHEAD OF A STRONGER COLD FRONT THAT LOOKS TO
DIVE THRU THE REGION FRIDAY INTO FRIDAY NIGHT. IMPROVING
CONDITIONS TO VFR LIKELY BEHIND THE FRONT ESPCLY ACROSS THE EAST
FOR THE WEEKEND.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...JH
NEAR TERM...JH
SHORT TERM...RAB
LONG TERM...PH/RAB
AVIATION...DS/JH/KM
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
126 AM EDT WED AUG 8 2012
.SYNOPSIS...
A PERIOD OF UNSETTLED WEATHER WILL CONTINUE THIS WEEK AS A FRONTAL
BOUNDARY OSCILLATES ACROSS THE MID ATLANTIC REGION. A STRONG COLD
FRONT WILL SWEEP ACROSS THE REGION ON FRIDAY...BRINGING A GENEROUS
COVERAGE OF SHOWERS AND STORMS...SOME POTENTIALLY STRONG. COOLER
AND DRIER WEATHER IS EXPECTED BY THE START OF THE NEXT WEEK AS
HIGH PRESSURE BUILDS INTO THE REGION.
&&
.NEAR TERM /THROUGH TODAY/...
AS OF 1000 PM EDT TUESDAY...
THE FRONTAL BOUNDARY PER LATEST MSAS THETA-E/LI GRADIENT LIES FROM
ERN KY ENE INTO CENTRAL VA. SHOWERS AND STORMS REMAIN ISOLATED
AT BEST WITH BEST CONCENTRATION ACROSS THE NC FOOTHILLS. STORM
MOVEMENT HAS BEEN ALL OVER THE PLACE WITH A WEAK FLOW. 00Z
SOUNDINGS FROM RNK/GSO SHOW STORM MOTION OF 3 KNOTS OR LESS.
LUCKILY HAVE NOT HAD STORMS LINGERING OVER ONE AREA TOO LONG AS
THEY TEND TO FADE AFTER AN HOUR. WILL SEE A WEAKENING TREND TO THE
ACTIVITY OVERNIGHT AND THINK A SLOW PUSH SOUTHEAST OF THE THETA-E
RIDGE WILL KEEP AT LEAST A LOW CHANCE/SLIGHT CHANCE POPS AROUND
ALL NIGHT FROM SOUTHSIDE VA/NW NC PIEDMONT WEST TO THE GRAYSON
HIGHLANDS/NC MTNS.
THE OTHER ISSUE TONIGHT WILL BE FOG AND HOW DENSE WILL IT GET. THE
DENSE CANOPY OF CIRROSTRATUS CONTINUES ACROSS THE ENTIRE FORECAST
AREA. MODELS SHOW DRIER AIR SNEAKING INTO THE MTNS AFTER 09Z...SO
WILL SEE SOME CLEARING. WILL HAVE TO WATCH SFC OBS AND SAT TRENDS
FOR POTENTIAL DENSE FOG ADVISORY. SOME SCHOOLS IN NC ARE STARTING
IN THE MORNING SO FOG WILL CAUSE A PROBLEM THERE POTENTIALLY. WILL
KEEP THE MENTION IN HWO FOR NOW.
RAISED TEMPS/DEWPOINTS UP A DEGREE OR TWO OVERNIGHT MAINLY EAST OF
THE NEW RIVER VALLEY WHERE THINK MORE CLOUDS ARE GOING TO LINGER
THROUGH WED MORNING.
PREVIOUS VALID DISCUSSION...
ON WEDNESDAY...WE EXPECT ANOTHER DAY COMPARABLE TO TODAY AS FAR
AS PRECIPITATION COVERAGE THANKS TO THE FRONT JUST TO OUR SOUTH.
HOWEVER...WITH HIGH PRESSURE NOSING SOUTH...CLOUD COVER SHOULD BE
LESS...AND A SLIGHTLY STRONGER CAP SHOULD MEAN THE ISOLATED
SHOWERS SHOULD BE EVEN MORE ISOLATED. DESPITE THE FRONT BEING
FARTHER TO OUR SOUTH...MORE SUNSHINE SHOULD YIELD HIGH
TEMPERATURES ON WEDNESDAY ABOUT THREE TO FIVE DEGREES WARMER THAN
TODAY.
&&
.SHORT TERM /TONIGHT THROUGH FRIDAY NIGHT/...
AS OF 242 PM EDT TUESDAY...
CHANCES FOR THUNDERSTORMS WILL INCREASE THROUGH THE SHORT TERM
PERIOD AS AN UPPER LEVEL TROF AMPLIFIES OVER THE GREAT LAKES AND
INTO THE OHIO VALLEY BY FRIDAY.
IN ADVANCE OF THIS SYSTEM...TEMPERATURES SHOULD WARM TOWARD THE
WARMER NAM MOS VALUES ON THURSDAY AS THE LOW LEVEL THERMAL RIDGE
NOSES INTO OUR AREA. BEST CHANCES FOR THUNDERSTORMS ON THURSDAY WILL
BE IN THE WEST AS A LEAD SHORT WAVE (OVERDONE BY THE GFS) APPROACHES
OUR AREA AND INTERACTS WITH A MODERATELY UNSTABLE AIRMASS. KEPT POPS
IN THE EASTERN PORTION OF THE FORECAST AREA ON THURSDAY AS WEAK LOW
LEVEL CONVERGENCE ALONG A LEE-SIDE TROF SHOULD GENERATE SCATTERED
CONVECTION.
THIS CONVECTION MAY LINGER A FEW HOURS BEYOND SUNDOWN THURSDAY NIGHT
WITH SUPPORT FROM THE WEAK UPPER LEVEL WAVE MOVING THROUGH.
THE TREND OF THE MODELS FOR FRIDAY`S SYSTEM HAS BEEN TO SLOW ITS
EASTWARD PROGRESS SLIGHTLY. BY 00Z (8 PM EDT) SATURDAY...MOST MODELS
SHOW THE COLD FRONT STILL WEST OF OUR FORECAST AREA. THE POTENTIAL
EXISTS FOR STRONG TO SEVERE STORMS TO ERUPT IN ADVANCE OF THIS
SYSTEM AS THE AREA COMES UNDER THE INFLUENCE OF THE RR QUAD OF AN
UPPER LEVEL JET ROTATING AROUND THE EASTERN SIDE OF THE APPROACHING
SHORT WAVE TROF. THE BIGGEST QUESTION CONCERNING THE POTENTIAL FOR
SEVERE WEATHER WILL BE THE INSTABILITY. CLOUDS ON FRIDAY SHOULD KEEP
HIGH TEMPS BELOW THURSDAY`S EXPECTED HIGHS AND MAY KEEP INSTABILITY
DOWN. THE GFS CRAVEN SIG SVR PARAMETER FORECAST KEEPS THE HIGHEST
POTENTIAL FOR SEVERE WEATHER TO OUR SOUTHEAST...WHERE INSTABILITY IS
FORECAST TO BE HIGHER. CONSIDERING THE STRENGTH OF THIS UPPER LEVEL
SYSTEM...WILL KEEP MENTION OF SVR WX IN THE HWO...ALONG WITH THE
THREAT FOR HEAVY RAIN WITH PWATS EXPECTED TO EXCEED 2 INCHES IN THE
EAST.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
AS OF 242 PM EDT TUESDAY...
THE LONG RANGE MODELS ARE IN GOOD AGREEMENT THAT THE EASTERN U.S.
REMAINS UNDER THE INFLUENCE OF AN UPPER TROF THAT DE-AMPLIFIES WITH
TIME. AHEAD OF THE UPPER TROF...A STRONG COLD FRONT WILL SWEEP
THROUGH FRIDAY NIGHT. THE 00Z ECMWF HOLDS MORE UPPER LEVEL ENERGY ON
THE WEST SIDE OF THE UPPER TROF AND KEEPS PRECIP LINGERING IN THE
FAR EASTERN PORTION OF OUR FORECAST AREA ON SATURDAY. SO WE HAVE
DELAYED THE ENDING TIME OF THE PRECIP UNTIL MIDDAY SATURDAY.
OTHERWISE...UPSLOPE RAIN SHOWERS CAN BE EXPECTED UNDER THE TROF AXIS
AND LOW LEVEL NORTHWEST WINDS.
DRIER...COOLER AND LESS HUMID AIR WILL INVADE THE REGION LATE
SATURDAY INTO SUNDAY. THE GEFS SHOWS 850MB TEMPS BY 18Z SATURDAY
WILL BE 1-2 STANDARD DEVIATIONS BELOW NORMAL. SO...LEANED TOWARD THE
COOLER ECMWF VALUES FOR TEMPS SATURDAY NIGHT THROUGH SUNDAY NIGHT.
TEMPERATURES WILL GRADUALLY WARM MONDAY AND TUESDAY AS THE UPPER
LEVEL TROF RELAXES...BUT INDIVIDUAL SHORT WAVES MOVING THROUGH AN
UPPER LEVEL NORTHWEST FLOW COMBINED WITH A WEAK SOUTHEAST FLOW WILL
GENERATE AFTERNOON SHOWERS AND STORMS.
&&
.AVIATION /05Z WEDNESDAY THROUGH SUNDAY/...
AS OF 100 AM EDT WEDNESDAY...
EXTENSIVE MID AND HIGH CLOUD CANOPY ASSOCIATED WITH WAVE/UPPER JET
PERSISTS ACROSS THE REGION TONIGHT WITH SOME LOWER STRATO-CU CIGS
ALONG THE WESTERN SLOPES ON THE EDGE OF THE CLOUD SHIELD. MAY SEE
A FEW ADDED SHRA DEVELOP OVER THE WEST THRU DAWN OTRW THE MAIN
CONCERN WITH FOG COVERAGE GIVEN LIMITED COOLING DUE TO CLOUD
COVER. THINK ONCE THIS BACKEDGE CLEARS SE WVA WILL SEE KBLF/KLWB
DROP TO MVFR/IFR...WITH LIFR AT KLWB IN THE NEXT FEW HOURS. THUS
DELAYED ONSET OF LOWER VSBYS BY A COUPLE OF HOURS IN THE WEST
INCLUDING KBCB WHICH MAY NOT DROP TO MVFR UNTIL JUST BEFORE DAWN.
APPEARS THE CLOUD SHIELD MAY HOLD FOR MUCH OF THE OVERNIGHT FROM
KROA EASTWARD WHICH WOULD CURTAIL MUCH FOG TO MAINLY SPOTTY
COVERAGE IN THE LOWER SPOTS BY MORNING. THEREFORE ALSO CUT BACK ON
FOG AT BOTH KDAN/KLYH UNTIL VERY LATE AND ONLY WENT WITH A BRIEF
PERIOD OF MVFR FOR NOW.
EXPECT ANY FOG OR LOW CIGS TO ERODE BY MID MORNING EXCEPT MAY HANG
IN A BIT LONGER IN THE VALLEY AROUND KLWB. ELSW SHOULD SEE MAINLY
VFR FOR MOST OF THE DAY WITH SCTD-BKN 4-6K FT CU FIELDS. ISOLATED
CONVECTION AGAIN POSSIBLE ESPCLY IN SPOTS ALONG THE BLUE RIDGE AND
OUT EAST BUT JUST TOO IFFY TO INCLUDE MENTION IN ANY TAF LOCATION
AT THIS POINT.
PROXIMITY OF OLD FRONT AND TROPICAL AIRMASS JUST TO THE SOUTH...
WHICH WILL BEGIN A NORTHWARD RETURN BY LATE WEEK...WILL MAINTAIN
A DAILY THREAT FOR PATCHY FLIGHT RESTRICTIONS IN VICINITY OF
MAINLY DIURNALLY DRIVEN SHOWERS/STORMS FOR MUCH OF THE REST OF THE
WEEK...WITH A CONTINUED THREAT FOR RESTRICTIONS INTO THE OVERNIGHT
PERIODS WHERE FOG DEVELOPS. MORE WIDESPREAD SHRA/TSRA LIKELY BY
WEEKS END AHEAD OF A STRONGER COLD FRONT THAT LOOKS TO DIVE THRU
THE REGION FRIDAY INTO FRIDAY NIGHT. IMPROVING CONDITIONS TO VFR
LIKELY BEHIND THE FRONT ESPCLY ACROSS THE EAST FOR THE WEEKEND.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...DS
NEAR TERM...DS/WP
SHORT TERM...PH
LONG TERM...PH
AVIATION...DS/JH/KM
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
931 PM CDT THU AUG 9 2012
.UPDATE...SHOWERS AND THUNDERSTORMS WILL CONTINUE TO DIMINISH OVER
WESTERN CWA THROUGH THE LATE EVENING AS VIGOROUS MID-LEVEL WAVE
SLIDES SOUTH OF THE REGION. FOCUS WILL THEN BE IN THE EAST WHERE
INCREASING LOW LEVEL CONVERGENCE AROUND DEEPENING LOW PRESSURE
OVER THE NORTHERN OHIO VALLEY AND LAKE ENHANCEMENT WILL RESULT IN
SCATTERED TO NUMEROUS SHOWERS AND ISOLATED THUNDERSTORMS IN THE
EAST THROUGH THE LATE NIGHT.
WITH INCREASING LOW LEVEL MIXING AND EXPECTED SCT-BKN MID LEVEL
CLOUDS...EXPECT ANY SIGNIFICANT FOG TO REMAIN CONFINED TO WI
RIVER VALLEY OF FAR WESTERN CWA LATE TONIGHT. THERMAL TROUGH SETS
UP OVER SOUTHERN WISCONSIN OVERNIGHT AND SEEING SOME SOUTHWEST
MOVEMENT OF MID-CLOUDS OVER NRN WI FROM LATEST IR IMAGES.
&&
.AVIATION/06Z TAFS/...SCATTERED TO NUMEROUS SHOWERS AND ISOLATED
THUNDERSTORMS WILL CONTINUE TO CAUSE CIGS TO FLIRT WITH MVFR AT
TIMES OVER EASTERN TAF SITES TONIGHT. CLOUDS AND LOW LEVEL MIXING
ARE EXPECTED TO PREVENT SIGNIFICANT FOG SO WL HOLD OUT OF TAFS FOR
NOW. CLEARING SKIES EXPECTED ON FRI.
&&
.MARINE...TIGHTENING PRESSURE GRADIENT ASSOCIATED WITH DEEPENING
LOW PRESSURE OVER THE CENTRAL GREAT LAKES OVERNIGHT ALONG WITH
VERY STEEP LOW LEVEL LAPSE RATES WILL ALLOW WIND GUSTS TO 35 KNOTS
TO REACH THE LAKE SURFACE LATE TONIGHT THROUGH FRIDAY. BESIDES
LATEST NAM SHOWING POTENTIAL FOR GALES ALONG WITH LATEST RAP AND
ARW MESOSCALE MODELS. THREAT FOR WATERSPOUTS WILL CONTINUE UNTIL
LATE TONIGHT.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 4 AM CDT FRIDAY FOR LMZ643>646.
GALE WARNING FROM 4 AM TO 6 PM CDT FRIDAY FOR LMZ643>646.
&&
$$
MBK
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
301 AM MDT FRI AUG 10 2012
.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 300 AM MDT FRI AUG 10 2012
MODELS CONTINUE TO SHOW EMBEDDED WAVES IN THE MOIST FLOW WHICH
COMBINING WITH AFTERNOON HEATING WILL BE THE FORCING MECHANISMS FOR
CONVECTION TODAY. RUC13 SHOWS THE BEST DYNAMICS MOVING ACROSS THE
EASTERN UTAH THIS MORNING INTO WEST-CENTRAL COLORADO BY THIS
AFTERNOON. EXPECT ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS TO
DEVELOP ACROSS THE ENTIRE FORECAST AREA...WITH THE BEST CHANCE OF
LOCALLY HEAVY RAIN ACROSS SOUTHERN AND EXTENDING NORTH ACROSS
CENTRAL SECTIONS TODAY. GUSTY OUTFLOW WINDS TO 50 MPH ARE ALSO
POSSIBLE NEAR STORMS ESPECIALLY ACROSS CENTRAL AND NORTHERN
SECTIONS.
MORE ENERGETIC TROF MOVING INTO THE PACIFIC NORTHWEST LATE THIS
EVENING WILL BE PUSHING ACROSS THE NORTHERN ROCKIES BY THIS TIME
TOMORROW NIGHT. AS IT DOES SO THE UPPER HIGH WILL BE SUPPRESSED
SOUTH OF THE 4 CORNERS REGION AND BRINGING IN SOME STRONGER
WESTERLY FLOW AS THE GRADIENT TIGHTENS. THE GOES DERIVED SATELLITE
IMAGERY THIS MORNING IS SHOWING GOOD MOISTURE OVER SOUTHERN
CALIFORNIA/SOUTHERN NEVADA AND THE 320K MOISTURE TRANSPORT VECTS
SHOW THIS MOISTURE BEING PULLED INTO OUR CWA AS IT GETS CAUGHT UP
IN THE FASTER WESTERLIES. THERE IS NO DISTINCT OR STRONG FORCING
FOR ASCENT EVIDENT IN THE SHORT TERM MODELS OVERNIGHT. HOWEVER
BOTH GFS/NAM SHOW PWATS SURGING THROUGH THE EARLY MORNING HOURS
AND POT VORT MOVING ALONG THE NORTHERN BORDER AS UPPER JET MAX
APPROACHES SO THINK THERE WILL BE SOME LINGERING CONVECTION TO
DEAL WITH AND BOOSTED POPS SLIGHTLY AND FAVORED ACROSS THE
NORTHERN 1/3 OF THE CWA.
WITH MOISTURE IN PLACE SATURDAY ADDED DYNAMICS FROM AN UPPER LEVEL
SPEED MAX MOVING OVER NORTHERN COLORADO SHOULD LEAD TO ANOTHER
ACTIVE DAY...THOUGH MODELS ARE A LITTLE DIFFERENT ON TIMING AND
COVERAGE. NAM SOLN PVU FIELDS SHOW THE SHORT WAVE ENERGY DIPPING
INTO NORTHERN COLORADO EARLY IN THE DAY AS IT HAS A STRONGER SYSTEM
OVER THE NORTHERN ROCKIES...GFS NOT DEEPENING THE SYSTEM QUITE AS
MUCH AND KEEPS ANY SHORT WAVE FORCING JUST NORTH OF OUR BORDER. BY
AFTERNOON HOWEVER BOTH MODELS HAVE UPPER LEVEL DIVERGENCE OVER OUR
CENTRAL CWA AND WEAK SUBSIDENCE FILTERING INTO THE NORTH. THE
INHERITED POPS FOR SATURDAY COVERED THIS WELL AND MADE JUST A FEW
TWEAKS UPWARD WITH SLIGHT HIGHER CONFIDENCE. STILL CHANCE OF HEAVY
RAINFALL BUT STORM MOTIONS WILL BE ON THE INCREASE WHICH MAY ENHANCE
THE OUTFLOW WIND THREAT. TEMPERATURES SHOWING DIVERGING TREND IN
GUIDANCE WITH NAM LOWERING DUE TO BEING MORE ACTIVE. USED A BLEND
BUT GAVE MORE WEIGHT TO THE WARMER GUIDANCE ATTM.
.LONG TERM...(SATURDAY NIGHT THROUGH THURSDAY)
ISSUED AT 300 AM MDT FRI AUG 10 2012
AS THE FLOW BECOME MORE NORTHWESTERLY IN THE WAKE OF THE NORTHERN
SYSTEM DRIER AIR LOOKS TO FILTER INTO THE CWA SATURDAY NIGHT WITH
PWATS KNOCKING BACK TO UNDER .75 OVER ALL BUT THE FAR SOUTHWESTERN
PORTION OF THE CWA. THIS SHOULD ALLOW CONVECTION TO TAPER OFF
OVERNIGHT AND LEAD TO COOLER LOW TEMPERATURES. THIS DRY AIR WILL BE
IN PLACE FOR ONLY A SHORT TIME AS PWATS LOOK TO REBOUND BY LATE
SUNDAY AS THE UPPER HIGH CENTERS OVER THE SOUTHERN HIGH PLAINS. WITH
A LATE MOISTURE PUSH SOME STORMS MAY MAKE IT INTO THE VALLEYS BUT
FOR THE MOST PART THINK MOST STORM WILL BE MORE ROOTED TO THE
TERRAIN.
NOT MUCH CHANGE IN THE WEATHER PATTERN INTO THE EXTENDED PERIOD...WITH
SOUTHERLY MOIST FLOW CONTINUING INTO THE EARLY WORK WEEK WITH A
CHANCE OF AFTERNOON AND EVENING THUNDERSTORMS EXPECTED EACH DAY
THROUGH WEDNESDAY. MODELS ARE HINTING AT THE RIDGE BUILDING TO OUR
WEST BY THURSDAY WHICH WOULD GENERATE SLIGHTLY DRIER CONDITIONS BY
LATE IN THE WEEK WITH A DECREASING THREAT OF SHOWERS AND
THUNDERSTORMS. EXPECT SEASONABLY WARM TEMPERATURES THROUGH THE
EXTENDED PERIOD.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY NIGHT) ISSUED AT
300 AM MDT FRI AUG 10 2012
INCREASED MOISTURE COMBINED WITH A WEAK DISTURBANCE MOVING OVER
THE NORTHERN HALF OF THE FORECAST AREA WILL CONTINUE TO BRING
ISOLATED SHOWERS AND A STRAY THUNDERSTORM DURING THE REMAINDER OF
THE NIGHT. HOWEVER...EXPECT MVFR CONDITIONS THROUGH THIS MORNING.
DIURNAL HEATING COMBINED WITH INCREASING MOISTURE WILL BRING
ANOTHER ROUND OF SCATTERED SHOWERS AND THUNDERSTORMS THIS
AFTERNOON WHICH WILL CONTINUE INTO THE EVENING HOURS. STORMS WILL
INITIALLY FORM OVER THE HIGHER TERRAIN RESULTING IN AREAS OF
MOUNTAIN OBSCURATION AND WIND GUSTS TO 45 MPH. STORMS WILL IMPACT
LOWER ELEVATIONS AFTER 20Z BRINGING ISOLATED MVFR CIGS AND VSBY TO
AIRPORTS ACROSS THE AREA...ESPECIALLY THOSE IN CLOSE PROXIMITY TO
MOUNTAINOUS TERRAIN. GUSTY OUTFLOW WINDS TO 50 MPH WILL ALSO BE A
MAIN CONCERN. SHOWERS AND EMBEDDED THUNDERSTORMS WILL DECREASE IN
AREAL COVERAGE AND INTENSITY AFTER SUNSET.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...NONE.
UT...NONE.
&&
$$
SHORT TERM...15/MPM
LONG TERM...MPM
AVIATION...MPM
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
559 AM EDT FRI AUG 10 2012
.SYNOPSIS...
A SLOW MOVING COLD FRONT WILL APPROACH THE FORECAST AREA FROM THE
NORTHWEST THROUGH TONIGHT. THE FRONT WILL BECOME DIFFUSE SATURDAY.
&&
.NEAR TERM /THROUGH TODAY/...
MOISTURE WILL BE HIGH AHEAD OF THE SLOW MOVING COLD FRONT TODAY.
EXPECT NUMEROUS SHOWERS AND THUNDERSTORMS MAINLY ASSOCIATED WITH THE
H85 JET. THE RAP AND NAM INDICATE THE JET WILL MAINLY AFFECT THE
FORECAST AREA EARLY TODAY. HOWEVER...CONTINUED HIGH MOISTURE AHEAD
OF THE FRONT AND DIURNAL HEATING SUPPORTS ADDITIONAL SHOWERS AND
THUNDERSTORMS LATER TODAY. LEANED TOWARD THE HIGHER GUIDANCE POPS.
CLOUDINESS SHOULD LIMIT INSTABILITY. THE NAM/S FORECAST OF WEAK
INSTABILITY APPEARS REASONABLE. IF SIGNIFICANT BREAKS AND STRONG
HEATING DOES OCCUR THEN THERE WILL BE ENOUGH SHEAR FOR A FEW SEVERE
THUNDERSTORMS. THE NAM SHOWS H85 WINDS NEAR 30 KNOTS MAINLY EARLY
TODAY. BOTH THE NAM AND GFS SHOW RAINFALL AMOUNTS LESS THAN
ONE-QUARTER OF AN INCH AND THESE GENERAL VALUES MAY BE CORRECT SINCE
THE H85 JET MAXIMUM SHOULD BE NORTHEAST OF THE FORECAST AREA WHICH
SHOULD LIMIT CONVERGENCE. HOWEVER...THERE WILL BE A THREAT OF
VERY HEAVY RAIN BECAUSE OF PRECIPITABLE WATER VALUES AROUND 2
INCHES. ALSO...EXPECT 1000-500 MB THICKNESSES NEAR 574 WHICH IS
THE PREFERRED VALUE FOR HEAVY RAIN IN AUGUST. USED THE GUIDANCE
CONSENSUS FOR THE TEMPERATURE FORECAST.
&&
.SHORT TERM /TONIGHT THROUGH SATURDAY NIGHT/...
MOISTURE AND CONVERGENCE ASSOCIATED WITH THE SLOW MOVING FRONT
SUPPORTS SHOWERS AND THUNDERSTORMS TONIGHT. HOWEVER...INSTABILITY
SHOULD BE LIMITED BY PREVIOUS CONVECTION AND DIURNAL COOLING.
FORECASTED POPS OF LIKELY EARLY AND CHANCE LATE. THE NAM AND GFS
SHOW THE FRONT LINGERING NEAR THE FORECAST AREA SATURDAY AND
SATURDAY NIGHT BUT DEEPER MOISTURE APPEARS TO SHIFT A LITTLE EAST
OF THE FORECAST AREA SATURDAY. THE NAM AND GFS MOS SUPPORT CHANCE
POPS. USED THE GUIDANCE CONSENSUS FOR THE TEMPERATURE FORECAST
THROUGH THE PERIOD.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
THE GFS SHOWS RIDGING TO THE SOUTH WITH LEE-SIDE TROUGHING IN THE
FORECAST AREA DURING MUCH OF THE EXTENDED PERIOD. THE PATTERN
SUPPORTS MAINLY DIURNAL SCATTERED THUNDERSTORMS. THE GFS ENSEMBLE
MEANS SUPPORT SLIGHT CHANCE OF CHANCE POPS. EXPECT TEMPERATURES NEAR
CLIMATOLOGY WITH LOWS IN THE LOWER 70S AND HIGHS IN THE LOWERS 90S.
&&
.AVIATION /09Z FRIDAY THROUGH TUESDAY/...
LOW LEVEL JET AFFECTING THE AREA TODAY. SOUTH WIND 5-10 KT THIS
MORNING WILL FAVOR STRATUS CLOUDS RATHER THAN DENSE FOG. GUIDANCE
HAVE COME INTO AGREEMENT WITH LIFR/IFR CIGS ACROSS THE TAF SITES
THROUGH 14-15Z. SO CONFIDENCE IS HIGH. COULD EVEN SEE A FEW SHOWERS
EARLY THIS MORNING. EXPECT IMPROVING CONDITIONS BY 15Z-16Z.
SOUTHWEST WINDS INCREASING TO 10-15KT BY MIDDAY WITH GUSTS NEAR 20
KNOTS. WIDESPREAD SHOWERS AND THUNDERSTORMS EXPECTED AGAIN THIS
AFTERNOON INTO TONIGHT.
EXTENDED AVIATION OUTLOOK...A COLD FRONT WILL MOVE THROUGH THE
REGION SATURDAY THROUGH SUNDAY. AN UNSETTLED WEATHER WILL PERSIST
THROUGH EARLY SUNDAY...WITH PERIODS OF SHOWERS AND THUNDERSTORMS.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
253 AM EDT FRI AUG 10 2012
.SYNOPSIS...
A SLOW MOVING COLD FRONT WILL APPROACH THE FORECAST AREA FROM THE
NORTHWEST THROUGH TONIGHT. THE FRONT WILL BECOME DIFFUSE SATURDAY.
&&
.NEAR TERM /THROUGH TODAY/...
MOISTURE WILL BE HIGH AHEAD OF THE SLOW MOVING COLD FRONT TODAY.
EXPECT NUMEROUS SHOWERS AND THUNDERSTORMS MAINLY ASSOCIATED WITH THE
H85 JET. THE RAP AND NAM INDICATE THE JET WILL MAINLY AFFECT THE
FORECAST AREA EARLY TODAY. HOWEVER...CONTINUED HIGH MOISTURE AHEAD
OF THE FRONT AND DIURNAL HEATING SUPPORTS ADDITIONAL SHOWERS AND
THUNDERSTORMS LATER TODAY. LEANED TOWARD THE HIGHER GUIDANCE POPS.
CLOUDINESS SHOULD LIMIT INSTABILITY. THE NAM/S FORECAST OF WEAK
INSTABILITY APPEARS REASONABLE. IF SIGNIFICANT BREAKS AND STRONG
HEATING DOES OCCUR THEN THERE WILL BE ENOUGH SHEAR FOR A FEW SEVERE
THUNDERSTORMS. THE NAM SHOWS H85 WINDS NEAR 30 KNOTS MAINLY EARLY
TODAY. BOTH THE NAM AND GFS SHOW RAINFALL AMOUNTS LESS THAN
ONE-QUARTER OF AN INCH AND THESE GENERAL VALUES MAY BE CORRECT SINCE
THE H85 JET MAXIMUM SHOULD BE NORTHEAST OF THE FORECAST AREA WHICH
SHOULD LIMIT CONVERGENCE. HOWEVER...THERE WILL BE A THREAT OF
VERY HEAVY RAIN BECAUSE OF PRECIPITABLE WATER VALUES AROUND 2
INCHES. ALSO...EXPECT 1000-500 MB THICKNESSES NEAR 574 WHICH IS
THE PREFERRED VALUE FOR HEAVY RAIN IN AUGUST. USED THE GUIDANCE
CONSENSUS FOR THE TEMPERATURE FORECAST.
&&
.SHORT TERM /TONIGHT THROUGH SATURDAY NIGHT/...
MOISTURE AND CONVERGENCE ASSOCIATED WITH THE SLOW MOVING FRONT
SUPPORTS SHOWERS AND THUNDERSTORMS TONIGHT. HOWEVER...INSTABILITY
SHOULD BE LIMITED BY PREVIOUS CONVECTION AND DIURNAL COOLING.
FORECASTED POPS OF LIKELY EARLY AND CHANCE LATE. THE NAM AND GFS
SHOW THE FRONT LINGERING NEAR THE FORECAST AREA SATURDAY AND
SATURDAY NIGHT BUT DEEPER MOISTURE APPEARS TO SHIFT A LITTLE EAST
OF THE FORECAST AREA SATURDAY. THE NAM AND GFS MOS SUPPORT CHANCE
POPS. USED THE GUIDANCE CONSENSUS FOR THE TEMPERATURE FORECAST
THROUGH THE PERIOD.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
THE GFS SHOWS RIDGING TO THE SOUTH WITH LEE-SIDE TROUGHING IN THE
FORECAST AREA DURING MUCH OF THE EXTENDED PERIOD. THE PATTERN
SUPPORTS MAINLY DIURNAL SCATTERED THUNDERSTORMS. THE GFS ENSEMBLE
MEANS SUPPORT SLIGHT CHANCE OF CHANCE POPS. EXPECT TEMPERATURES NEAR
CLIMATOLOGY WITH LOWS IN THE LOWER 70S AND HIGHS IN THE LOWERS 90S.
&&
.AVIATION /07Z FRIDAY THROUGH TUESDAY/...
LOW LEVEL JET AFFECTING THE AREA TODAY. SOUTH WIND 5-10 KT THIS
MORNING WILL FAVOR STRATUS CLOUDS RATHER THAN FOG. GUIDANCE HAVE
COME INTO AGREEMENT WITH LIFR/IFR CIGS ACROSS THE TAF SITES THROUGH
14-15Z. SO CONFIDENCE IS HIGH. COULD EVEN SEE A FEW SHOWERS EARLY
THIS MORNING. EXPECT IMPROVING CONDITIONS BY 15Z-16Z. SOUTHWEST
WINDS INCREASING TO 10-15KT BY MIDDAY WITH GUSTS NEAR 20 KNOTS.
WIDESPREAD SHOWERS AND THUNDERSTORMS EXPECTED AGAIN THIS AFTERNOON
INTO TONIGHT.
EXTENDED AVIATION OUTLOOK...AN UNSETTLED WEATHER WILL PERSIST
THROUGH SUNDAY. A COLD FRONT WILL MOVE SLOWLY THROUGH THE REGION
FRIDAY THROUGH SUNDAY...THEREBY HOLDING A GOOD CHANCE FOR CONVECTION.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
305 AM CDT FRI AUG 10 2012
.DISCUSSION...
ISSUED 305 AM CDT FRI AUG 10 2012
SHORT TERM...TODAY THROUGH SUNDAY
UNSEASONABLY DEEP UPPER-LEVEL LOW WILL CONTINUE TO SPIN OVER THE
GREAT LAKES TODAY. POCKET OF VERY COLD AIR ALOFT CHARACTERIZED BY
500MB TEMPS OF -14 TO -16C WILL PRODUCE ENOUGH DAYTIME INSTABILITY
TO TRIGGER PLENTY OF DIURNAL CLOUDINESS AND EVEN A FEW ISOLATED
SHOWERS ALONG THE ILLINOIS/INDIANA BORDER. TIGHTENING PRESSURE
GRADIENT BETWEEN DEVELOPING SURFACE LOW OVER THE OHIO RIVER VALLEY
AND APPROACHING HIGH ACROSS THE PLAINS WILL CREATE GUSTY NORTHERLY
WINDS...WITH FORECAST SOUNDINGS SUGGESTING GUSTS TO AROUND 25 MPH.
THANKS TO THE BRISK NORTHERLY FLOW AND PARTIAL CLOUD COVER...HIGH
TEMPS WILL REMAIN BELOW NORMAL FOR THIS TIME OF YEAR IN THE MIDDLE
TO UPPER 70S.
SKIES WILL CLEAR AND WINDS WILL DIMINISH TONIGHT...ALLOWING
EXCELLENT RADIATIONAL COOLING CONDITIONS TO DEVELOP. OVERNIGHT LOW
TEMPERATURES WILL GENERALLY DROP INTO THE MIDDLE TO UPPER
50S...WITH A FEW FAVORED LOCATIONS DIPPING INTO THE LOWER 50S.
PLENTY OF SUNSHINE AND CONTINUED COOL WEATHER WILL CONTINUE INTO
SATURDAY...WITH AIRMASS MODIFICATION PRODUCING HIGHS AROUND 80 DEGREES.
MODELS CONTINUE TO ADVERTISE NEXT SHORT-WAVE APPROACHING FROM THE
NORTHWEST BY LATE SUNDAY. GIVEN DRY AIRMASS AND SLIGHTLY SLOWER
ARRIVAL OF WAVE...WILL KEEP PRECIP CHANCES OUT OF THE FORECAST
THROUGH THE DAY SUNDAY. STRONGER SYNOPTIC LIFT WILL ARRIVE WITH
THE WAVE BY SUNDAY NIGHT...SO WILL INTRODUCE A CHANCE FOR
SHOWERS/STORMS AT THAT TIME.
LONG TERM...MONDAY THROUGH THURSDAY
SCATTERED SHOWERS/STORMS WILL LINGER INTO MONDAY...BEFORE WAVE
PUSHES EAST OF THE REGION AND DRY WEATHER RETURNS MONDAY NIGHT AND
TUESDAY. UPPER HEIGHTS WILL BEGIN TO RISE IN THE WAKE OF THE
SYSTEM...ALTHOUGH LATEST MODEL RUNS DO NOT BUILD RIDGING INTO THE
MIDWEST QUITE AS AGGRESSIVELY AS PREVIOUS RUNS. WILL SEE A
DEFINITE WARMING TREND NEXT WEEK...HOWEVER HAVE TEMPERED THE
READINGS A BIT...WITH HIGHS ONLY BACK INTO THE UPPER 80S BY
WEDNESDAY. MODELS STILL SHOWING SOME TIMING DISCREPANCIES WITH
NEXT APPROACHING WAVE...BUT CONSENSUS BRINGS IT INTO THE AREA
WEDNESDAY NIGHT/THURSDAY. GIVEN PROJECTED STRENGTH OF FEATURE AND
EXPECTED SUPPLY OF AVAILABLE MOISTURE...THINK CHANCE POPS FOR
SHOWERS/STORMS ARE WARRANTED AT THAT TIME.
BARNES
&&
.AVIATION...
ISSUED 1145 PM CDT THU AUG 9 2012
MAIN CONCERN IS WITH TIMING FOR POTENTIAL MVFR/IFR CEILINGS. LARGE
UPPER LOW CURRENTLY CENTERED JUST NORTH OF KORD AND WILL MOVE INTO
NORTHERN INDIANA BEFORE SUNRISE. SATELLITE AND SURFACE OBS SHOWING
AN INCREASE IN MVFR CONDITIONS NEAR/NORTH OF THIS LOW...AND THIS
WILL BE SWINGING SOUTHWARD ACROSS ILLINOIS OVER THE NEXT FEW
HOURS. LATEST GUIDANCE FROM THE RAP MODEL SUGGESTING THESE LOWER
CEILINGS WILL PUSH INTO CENTRAL ILLINOIS FROM THE NORTHEAST... SO
WILL BEGIN WITH THE LOWER CEILINGS NEAR KBMI/KCMI AT THE START OF
THE TAF PERIOD WITH SOME TEMPO VFR CONDITIONS THROUGH ABOUT 08Z.
THE REMAINDER OF THE TAFS SHOULD SEE CLOUDS LOWERING TO 1000-2000
FEET BEGINNING AROUND 08Z...ALTHOUGH SOME BREAKS IN THE CLOUDS
WILL STILL BE POSSIBLE. A STEADIER BREAK-UP OF THE CLOUDS IS
EXPECTED TO DEVELOP SHORTLY AFTER SUNRISE...AS THE LOW PULLS EAST
OF THE REGION. VFR CONDITIONS SHOULD PREVAIL BY LATE MORNING.
NORTH WINDS SHOULD PICK UP SOME ON FRIDAY...AS CLOUDS DECREASE AND
ALLOW FOR SOME MIXING TO TAKE PLACE FROM AROUND 5000 FEET. MAY SEE
SOME GUSTS OF 15-20 KNOTS IN A FEW AREAS DURING THE MIDDAY AND
AFTERNOON HOURS. WINDS WILL DIMINISH TOWARD SUNSET.
GEELHART
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1146 PM CDT THU AUG 9 2012
.DISCUSSION...
ISSUED 833 PM CDT THU AUG 9 2012
STRONGEST CONVECTION WHICH PRODUCED SEVERE WEATHER REPORTS FROM
BLOOMINGTON TO PARIS EASTWARD HAS PUSHED INTO INDIANA...BUT SOME
SHOWERS AND THUNDERSTORMS LINGER OVER CENTRAL AND SOUTHEAST
ILLINOIS. MANY OF THESE WERE ALONG AN OUTFLOW BOUNDARY...WHICH
WAS IN AN ARCH FROM FULTON COUNTY TO EFFINGHAM...THEN NORTHEAST TO
NEAR DANVILLE. MESOANALYSIS SHOWING SOME AREAS OF CAPES ABOVE 1000
J/KG LINGERING OVER CENTRAL AND SOUTHEAST ILLINOIS. HOWEVER... THE
WINDOW OF OPPORTUNITY FOR ADDITIONAL SEVERE WEATHER IS
NARROWING...AS ANOTHER BOUNDARY DROPS SOUTH FROM NORTHERN ILLINOIS
AND LOWERS TEMPERATURES INTO THE 60S. THE CLEARING THAT HAS BEEN
OCCURRING OVER THE CWA WILL FILL BACK IN AGAIN...AS A LARGE UPPER
LOW DROPS SOUTH OUT OF WISCONSIN.
HAVE SENT SOME ZONE/GRID UPDATES FOR THE LATEST CONVECTIVE
TRENDS...AND SOME MINOR ADJUSTMENTS TO THE HOURLY TEMPERATURES.
OVERALL LOWS FOR TONIGHT STILL LOOK GOOD.
GEELHART
&&
.AVIATION...
ISSUED 1145 PM CDT THU AUG 9 2012
MAIN CONCERN IS WITH TIMING FOR POTENTIAL MVFR/IFR CEILINGS. LARGE
UPPER LOW CURRENTLY CENTERED JUST NORTH OF KORD AND WILL MOVE INTO
NORTHERN INDIANA BEFORE SUNRISE. SATELLITE AND SURFACE OBS SHOWING
AN INCREASE IN MVFR CONDITIONS NEAR/NORTH OF THIS LOW...AND THIS
WILL BE SWINGING SOUTHWARD ACROSS ILLINOIS OVER THE NEXT FEW
HOURS. LATEST GUIDANCE FROM THE RAP MODEL SUGGESTING THESE LOWER
CEILINGS WILL PUSH INTO CENTRAL ILLINOIS FROM THE NORTHEAST... SO
WILL BEGIN WITH THE LOWER CEILINGS NEAR KBMI/KCMI AT THE START OF
THE TAF PERIOD WITH SOME TEMPO VFR CONDITIONS THROUGH ABOUT 08Z.
THE REMAINDER OF THE TAFS SHOULD SEE CLOUDS LOWERING TO 1000-2000
FEET BEGINNING AROUND 08Z...ALTHOUGH SOME BREAKS IN THE CLOUDS
WILL STILL BE POSSIBLE. A STEADIER BREAK-UP OF THE CLOUDS IS
EXPECTED TO DEVELOP SHORTLY AFTER SUNRISE...AS THE LOW PULLS EAST
OF THE REGION. VFR CONDITIONS SHOULD PREVAIL BY LATE MORNING.
NORTH WINDS SHOULD PICK UP SOME ON FRIDAY...AS CLOUDS DECREASE AND
ALLOW FOR SOME MIXING TO TAKE PLACE FROM AROUND 5000 FEET. MAY SEE
SOME GUSTS OF 15-20 KNOTS IN A FEW AREAS DURING THE MIDDAY AND
AFTERNOON HOURS. WINDS WILL DIMINISH TOWARD SUNSET.
GEELHART
&&
.PREV DISCUSSION...
ISSUED 300 PM CDT THU AUG 9 2012
INITIAL CONCERN IS WITH CHANCES FOR SEVERE STORMS LATE THIS
AFTERNOON AND THIS EVENING. NEXT HIGHLIGHTS WILL BE THE COOLER
AIRMASS FOR THE WEEKEND FOLLOWED BY A COUPLE OF CHANCES FOR RAIN
SUNDAY NIGHT INTO MONDAY AND WEDNESDAY NIGHT INTO THURSDAY.
OUR CURRENT WEATHER IS BEING DRIVEN BY WEAK CYCLOGENESIS THAT
APPEARS TO BE CENTERED JUST NORTH OF PEORIA...ALONG A SURFACE
TROUGH EXTENDING NORTH FROM LOW PRESSURE IN SOUTHERN IL. THAT LOW
WAS LOCATED ALONG A STATIONARY FRONT THAT EXTENDED ROUGHLY ALONG
THE OHIO RIVER VALLEY AND SOUTHWEST INTO OKLAHOMA. ALOFT...A WELL
DEVELOPED TROUGH ACROSS THE GREAT LAKES WAS BEING REINFORCED BY A
CLOSED LOW AT 500MB DROPPING SOUTH FROM NW WISCONSIN TOWARD
NORTHERN IL. A NORTH-SOUTH ORIENTED 115 KT 300MB JET MAX WAS
POSITIONED JUST WEST OF THE 500MB LOW...AND ROTATING SOUTH AND
EAST AROUND THE UPPER TROUGH.
MODELS ARE HAVING A DIFFICULT TIME CATCHING UP WITH THE WEAK
SURFACE PRESSURE PATTERN THAT IS BEGIN EASILY ALTERED BY STORM
OUTFLOWS/GUST FRONTS/COLD POOLS. IN GENERAL...WE DECIDED TO LEAN
MORE CLOSELY WITH THE 00Z ECMWF.
SHORT TERM...TONIGHT THROUGH SUNDAY.
SOME FILTERED SUNSHINE HAS HELPED THE AIRMASS DESTABILIZE EARLY
THIS AFTERNOON. SFC BASED CAPES HAVE CLIMBED TO AROUND 1500
J/KG WITH MU CAPES OF 2000 J/KG JUST EAST OF THE SFC CYCLOGENESIS
NEAR PEORIA. EFFECTIVE SHEAR HAS INCREASED TO AROUND 25 TO 30KT.
THAT HAS HELPED A FEW STORMS DEVELOP UNDER THE LOW NW OF PEORIA.
VERTICAL DEVELOPMENT OF THOSE STORMS HAVE REMAINED IN CHECK SO
FAR...WITH STORM TOPS AROUND 30K FT. ENOUGH OF A DRY LAYER BELOW
700MB WILL ALLOW FOR SOME ENHANCED DOWNBURST POTENTIAL WITH ANY
STRONGER STORMS...AND THE FREEZING LEVEL DOWN AROUND 12K FT WILL
BE MORE FAVORABLE FOR HAIL PRODUCTION.
WE WILL MONITOR STORM PROGRESS AND DEVELOPMENT CLOSELY FOR AN
INTENSIFICATION...BUT THE BETTER CHANCES FOR SEVERE STORMS APPEARS
TO BE IN OUR EAST AND SOUTHEAST COUNTIES CLOSER TO THE STATIONARY
FRONT AND SURFACE LOW IN SOUTHERN ILLINOIS. THE DY1 SLIGHT RISK
WAS EXPANDED WESTWARD AT 17Z TO INCLUDE ALL BUT OUR FAR W-NW
COUNTIES...SO WILL NOT RULE OUT SEVERE CHANCES AS FAR WEST AS THE
ILLINOIS RIVER.
WE WILL KEEP HIGH CHANCE POPS FOR EVERYWHERE THE REST OF THE
AFTERNOON AND ACROSS THE EASTERN HALF THIS EVENING...AS THE WEAK
SURFACE LOW NEAR PEORIA SLIDES EAST-SOUTHEAST TOWARD INDIANA.
AFTER MIDNIGHT...ANY LINGERING SHOWERS/STORMS SHOULD BE CONFINED
TO OUR COUNTIES EAST OF I-57.
THE COLD POOL ALOFT WILL BE REINFORCED BY THE PASSAGE OF THE CLOSED
LOW ACROSS NE ILLINOIS LATER TONIGHT AND FRIDAY. THE UPPER LOW IS
THEN EXPECTED TO ROTATE BACK NORTHEAST INTO THE CENTRAL GREAT
LAKES AND LINGER THERE SATURDAY BEFORE LIFTING NORTHEAST INTO
ONTARIO SAT NIGHT. THAT SCENARIO WILL PUT CENTRAL ILLINOIS IN A
COOL NORTHWEST FLOW ALOFT...WITH WEAK SURFACE HIGH PRESSURE
HELPING TO PROVIDE DRY CONDITIONS FRIDAY INTO SUNDAY.
BELOW NORMAL HIGHS ARE EXPECTED FRIDAY THROUGH SUNDAY. FRIDAY WILL
BE THE COLDEST DAY WITH HIGHS ONLY IN THE UPPER 70S...THEN HIGHS
WILL CLIMB INTO THE LOWER 80S FOR SAT AND SUN.
THE ECMWF AND GFS BOTH SHOW A WEAK SFC LOW EJECTING FROM THE
PLAINS ACROSS MISSOURI ON SUNDAY...POSSIBLY BRINGING A CHANCE OF
RAIN WEST OF I-55 SUNDAY AFTERNOON. WE DECIDED TO INTRODUCE SLIGHT
CHANCE POPS SUNDAY...THEN INCREASE TO CHANCE POPS SUNDAY NIGHT AS
THE LOW REACHES WESTERN IL AND THE 500MB TROUGH DROPS SOUTHEAST
INTO NORTHERN IL. A FEW STORMS MAY DEVELOP SUNDAY NIGHT DUE TO THE
STEEP LAPSE RATES IN THE COLD POOL ALOFT.
LONG TERM...MONDAY THROUGH THURSDAY
WE HELD ONTO SLIGHT CHANCE POPS ON MONDAY BEFORE THE SURFACE
TROUGH DISSIPATES AND THE UPPER TROUGH SLIDES EAST OF IL. A
REINFORCING PUSH OF COLDER AIR ALOFT WILL HELP TO KEEP LOWS
SLIGHTLY BELOW NORMAL AGAIN ON MONDAY...IN THE LOW TO MID 80S.
WEAK SURFACE RIDGING SHOULD GIVE US BETTER CHANCES OF REMAINING
DRY AGAIN MONDAY NIGHT THROUGH WEDNESDAY. HOWEVER...THE NORTHWEST
FLOW ALOFT ALWAYS LEAVES THE DOOR OPEN FOR AN UNRESOLVED SHORTWAVE
TO SLIP INTO THE AREA AND KICK OFF A FEW SHOWERS/STORMS. FOR
NOW...WE KEPT THE FORECAST DRY UNTIL A MORE PROMINENT WEATHER
DISTURBANCE IS FORECAST TO ARRIVE WED NIGHT AND THURSDAY.
SOME WEAK SOUTHERLY FLOW DEVELOPING ON WED SHOULD HELP HIGH TEMPS
RETURN TO THE UPPER 80S BOTH WED AND THURS.
SHIMON
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS DES MOINES IA
404 AM CDT FRI AUG 10 2012
.SHORT TERM /TONIGHT/...
MAIN FOCUS TODAY WILL BE ON CLOUD COVER AND TEMPERATURES FOR THE
NEAR TERM. CWA TO REMAIN BENEATH CYCLONIC FLOW ALOFT...WITH WEAK CAA
EXPECTED THROUGHOUT THE DAY. SOME LOW LEVEL MOISTURE RESULTING IN AN
AREA OF LOW STRATUS CONTINUES TO DEVELOP OFF TO THE NORTHEAST OF THE
CWA...WITH MODEL PROGGING THIS AREA OF STRATUS TO CONTINUE TO
SPREAD/ADVECT INTO THE NORTHERN/EASTERN HALF OF THE CWA THROUGH
SUNRISE. HRRR MODEL AND GOES-R WRF FORECAST BOTH HANDLING THE
DEVELOPMENT OF THIS STRATUS WELL AND HAVE TAILORED SKY GRIDS TOWARD
THE MODEL/SATELLITE PRODUCT TRENDS. EXPECT STRATUS TO LIFT/BREAK UP
TOWARD MID/LATE MORNING ACROSS THE AREA...WITH RESULTANT MID LEVEL
CU FIELD POSSIBLE. OTHERWISE MUCH DRIER TO MOVE INTO THE CWA WITH
DEWPOINTS EXPECTED TO CONTINUE TO DROP TO AROUND 50 POSSIBLY EVEN
INTO THE 40S WITH DRIER AIR MIXING DOWN AND ADVECTING INTO THE CWA
IN NORTHERLY FLOW. WITH THE CAA...EXPECT TEMPS TO BE A FEW DEGREES
COOLER THAN YESTERDAY WITH HIGHS MAINLY IN THE UPPER 70S TO AROUND
80.
.LONG TERM /TONIGHT THROUGH THURSDAY/...
CANADIAN HIGH PRESSURE MOVING INTO THE NORTHERN PLAINS EARLY THIS
MORNING WITH TEMPERATURES DIPPING INTO THE LOW TO MID 40S OVER THE
SOUTHEAST QUADRANT. THIS SYSTEM WILL SETTLE SOUTH TODAY AND BE
STRETCHED OVER MUCH OF THE CENTRAL AND NORTHERN PLAINS TONIGHT.
WHILE SOME MODIFICATION OF TEMPERATURES IS EXPECTED...SHOULD HAVE
OVERNIGHT LOWS TONIGHT TOUCHING THE MID 40S AT A FEW LOCATIONS
ACROSS THE NORTH AND INTO THE LOW TO MID 50S ELSEWHERE. THE CLOSED
UPPER LOW THAT AFFECTED THE AREA ON THURSDAY WILL BE SHIFTING SLOWLY
NORTHEAST ACROSS THE CENTRAL GREAT LAKES THROUGH MID DAY SATURDAY
BEFORE GAINING STEAM SATURDAY NIGHT AS ANOTHER CLOSED UPPER LOW
MOVES INTO CENTRAL CANADA. THIS WILL ALLOW A TRANSITION TO A MORE
PROGRESSIVE NORTHWEST FLOW THAT WILL PERSIST THROUGH MUCH OF THE
EXTENDED.
A FAIRLY SIGNIFICANT SYSTEM WILL ARRIVE OVER THE PACIFIC NW LATE
TODAY THEN MOVE ACROSS THE ROCKIES AND PRODUCE LEE SIDE CYCLOGENESIS
INTO SATURDAY. SATURDAY WILL BE ANOTHER PLEASANT DAY AND EXPECT
TEMPERATURES TO BE NEAR THE HIGH END OF GUIDANCE WITH DRY SFC AIR
HEATING UP EFFICIENTLY. MID LEVEL THETA-E ADVECTION WILL COMMENCE
SATURDAY NIGHT WITH THE INITIAL WAVE BEING SPENT ON MID LEVEL
SATURATION. GULF MOISTURE WILL BREAK FREE AND BEGIN TO STREAM
NORTHWARD SATURDAY NIGHT AS WELL WITH THE MOISTURE ADVECTION
ARRIVING LATE AIDED BY AN INCREASING LOW LEVEL JET APPROACHING 40
KTS. THE COMBINATION OF THE MULTI LEVEL KINEMATICS AND
THERMODYNAMICS WILL RESULT IN A DEEPLY FORCED SYSTEM WITH SHOWERS
AND THUNDERSTORMS ARRIVING OVER THE WEST AFTER MIDNIGHT. ADDITIONAL
CHANCES WILL CONTINUE SUNDAY AND SUNDAY NIGHT WITH AS THE SECOND
SEGMENT OF THE UPPER LEVEL SYSTEM ARRIVES ALONG WITH THE SFC LOW
REFLECTION. GENERAL AGREEMENT DEVELOPING THAT THE SFC LOW WILL SHIFT
EAST ACROSS SOUTHERN IA AND WOULD ALLOW A PORTION OF THE WARM SECTOR
TO LIFT INTO THE STATE. HIGH VARIABILITY POSSIBLE WITH HIGH
TEMPERATURES ON SUNDAY WHERE HIGHS COULD STRUGGLE IN THE 60S UNDER
INCREASING CLOUDS AND MORE PROLONGED PRECIPITATION WHILE RISING WELL
INTO THE 80S SOUTH WHERE SOME SUN COULD BE POSSIBLE. THIS COULD LEAD
TO AN AREA OF SFC BASED THUNDERSTORMS AND AN AREA WITH SEVERE
POTENTIAL. PRECIPITATION CHANCES CONTINUE OVER MAINLY THE EAST
SUNDAY EVENING BEFORE ENDING.
THE REMAINDER OF THE EXTENDED IS HIGHLIGHTED BY SEVERAL IMPULSES
RIPPLING THROUGH THE NW FLOW WHILE A DEEP UPPER LEVEL LOW DROPS INTO
ALBERTA AND MANITOBA BY MID WEEK. OVERALL TIMING BECOMES DIFFICULT
UNDER THESE SITUATIONS BUT GENERAL CONSENSUS IS A WEAK WAVE ARRIVING
TUE NIGHT INTO WED WITH A MORE SIGNIFICANT SYSTEM IMPACTING THE AREA
TOWARD THE END OF THE PERIOD AS ENERGY ASSOCIATED THE SOUTHERN
CANADA SYSTEM ARRIVES.
&&
.AVIATION...10/06
HIGH PRESSURE FROM CENTRAL ONT INTO SWRN NEBRASKA WILL BUILD SOUTH
INTO IOWA THROUGH THE PERIOD. VFR CONDITIONS ARE EXPECTED FOR THE
MORT PART WITH A NE-NLY FLOW OVER THE SITES. SOME FOG IS POSSIBLE
AROUND SUNRISE OVER THE NORTH WHERE WINDS WILL LIGHTEN UP AND IN THE
EAST WHERE SHOWERS MOVED THROUGH IN THE EVENING. TIMEFRAME IS
10Z-14Z.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM...BEERENDS
LONG TERM...DONAVON
AVIATION...MS AUG 12
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
1256 AM EDT FRI AUG 10 2012
...Updated Aviation Discussion...
.Forecast Update...
Issued at 1145 PM EDT Thu Aug 9 2012
Updated the forecast to adjust POPs a bit. The 0Z NAM seems to have
the best handle on convection this evening. Convection over central
IN right around the sfc low should continue to move east over the
next 2-4 hrs and may develop a bit further south into our southern
Indiana counties. However, these storms should struggle to reach
severe levels given the lack of forcing further removed from the
front and main upper level wave as well as lack of instability due
to storms early this evening.
The next area of focus looks to be southern IL as wind shear
profiles increase with the upper shortwave dropping south through IL
and into western KY through the early morning hours. SPC
mesoanalysis indicates good moisture convergence along the sfc front
over southern IL with some isld-sct cells noted over western IL to
southeast MO. DCAPE values are at a relative max over southern IL
and western KY. Would expect new convection to develop over
southern IL over the next 2-4 hours, initially push SSE, and then
pivot more easterly into our area during the pre-dawn hours and as
the shortwave pivots aloft. This will probably be our best chance
for strong to severe convection overnight. Forecast confidence in
this occurring is low to medium given model inconsistencies and
banking on convection developing over southern IL.
&&
.Short Term (Tonight through Friday Night)...
Issued at 331 PM EDT Thu Aug 9 2012
...Active Period of Weather Expected This Afternoon and Tonight...
Fairly active period of weather is shaping up for the Ohio Valley
this afternoon and tonight. In the near term, mid-level shortwave
combined with surface temperatures hitting convective temperatures
has resulted in convection firing across the region. Several areas
of convection are occurring across the area. The first is an
organizing line near the I-75 corridor in our eastern sections.
This is being forced by the aforementioned mid-level wave and by
diurnal heating. This activity will continue to head east and into
WFO JKL`s area over the next hour or so. Further west, a well
defined residual outflow boundary was located along our border with
WFO IND. This boundary extends from northern Dubois county NE to
Jefferson County. Convection is firing along this boundary due to
strong moisture convergence and diurnal heating. This activity
should head east-southeast over the next few hours. Finally
additional convection is firing also over west KY. Based on the
latest runs of the LMK WRF and 4km HRRR runs, this activity should
also head east-southeast and may impact our far southwestern
counties later this afternoon. Based on RUC proximity soundings,
this afternoon`s convective activity is likely to remain in the
pulse variety with damaging winds, torrential rains and intense CG
lightning being the main threats.
Latest deterministic and ensemble model runs seem to be showing some
forecast convergence with the forecast for later this evening and
overnight. First mid-level trough will scoot east this evening
while a secondary and more potent mid-level trough dropping down
into the Ohio Valley late tonight. As this wave drops south,
surface cyclone near KSTL will shift northeast while associated
surface cold drags behind. Strong mid-level height falls will
result in widespread synoptic scale lift across the region late
tonight. This combined with forcing along the front should result
in a secondary line of convection developing to our northwest and
slide southeast overnight. Despite this line moving through during
an instability minimum, the upper level dynamics appear to be strong
enough to support convection despite the meager instability.
Current thinking is that a convective line will generate along the
I-70 corridor and then drop southeast overnight. The line will
likely be strong to possibly severe especially to our northwest.
However, as the line heads southeast, it is possible that line may
weaken a bit as it slides through KY. Convection should be pushing
through southern Indiana in the 04-06Z time frame and then through
KY in the 06-11Z time frame. Have gone ahead and bumped up PoPs for
the overnight period. Lows will remain mild with temperatures
falling into the lower-mid 60s in the northwest and mid-upper 60s
elsewhere.
For Friday, the main forecast change here is that a lot more cloud
cover will be likely during the morning hours. Latest model
time-height model cross sections show plenty of low-level moisture
lingering behind the frontal boundary as it pushes through. Thus,
mostly cloudy skies seem very likely in the morning followed by
progressive clearing during the afternoon and into the evening
hours. Highs tomorrow will be quite cool compared to what we`ve
seen over the last few months. We should see readings in the upper
70s in the east with upper 70s to lower 80s in the central and
west. Lows Friday night will be quite comfortable with lows in the
mid-upper 50s.
.Long Term (Saturday through Thursday)...
Issued at 315 PM EDT Thu Aug 9 2012
...Mostly Sunny, Dry, and Cool Weekend Ahead...
A vertically stacked unseasonably far south and strong closed low
will begin to slowly fill over Lake Huron Saturday. This system will
slowly weaken and slowly lift north towards St. James Bay by late
Sunday. In its wake, it will leave residual troughing across the
western Great Lakes and the upper Midwest.
By early Saturday, the occluded front related to this upper low will
already have moved well east of the Commonwealth. Much drier and
cooler air originating in Canada, will have overspread the state by
dawn Saturday.
Expect mostly clear skies and relatively cool temperatures for the
upcoming weekend. Dewpoints will likely fall into the lower 50s by
Saturday afternoon. Highs will struggle to exceed 80 on Saturday
with highs on Sunday warming just a few degrees into the lower 80s.
Overnight lows early Sunday will quite likely reach into the upper
50s, with perhaps our urban areas remaining near 60.
A broad longwave trough will remain centered roughly over the Great
Lakes during the early portion of next week. This will ensure no
repeat of the excessively hot temperatures of early August anytime
soon. Both the latest GFS and the ECMWF show a disturbance sliding
southeast towards the base of this longwave trough Monday and
Tuesday. This system will approach the Commonwealth by late Monday.
At the surface, this system will likely aid in the formation of a
weak surface trough that may serve as a focus for convection
beginning late Monday, possibly continuing through the bulk of
Tuesday. Will introduce a chance of storms for the later half of
Monday, extending through Tuesday.
Temperatures will warm a bit within the Monday through Thursday time
period. However, even by Wednesday through Friday, temperatures
will not exceed our seasonal mid-August averages with highs
remaining in the upper 80s to around 90
&&
.Aviation (06Z TAF issuance)...
Issued at 1255 AM EDT Fri Aug 10 2012
Main focus overnight will be convective chances ahead of a cold
frontal passage. Currently, frontal boundary appears to be oriented
along, but just north of the Ohio River and will remain nearly
stationary for a few more hours. Then, a potent upper level wave
will swing through the area toward dawn, helping to usher the
surface front through. Chances for showers and storms will continue
until this passage occurs later this morning, with the best chance
of a storm at SDF. Am not confident enough to go with a prevailing
thunder group at this time so will leave VCTS/CB mention until 7 AM
EDT.
Frontal boundary looks to move through the TAF sites sometime
between 6 AM and 11 AM with a brief potential for low MVFR or IFR
ceilings. Surface winds will also veer to westerly and then
northwesterly through the end of the forecast period with the
passage. Speeds should generally be around 10 mph. Ceilings should
improve through midday and the afternoon, however at least MVFR
stratocu will again be possible overnight tonight.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
KY...NONE.
$$
Update...........AMS
Short Term.......MJ
Long Term........JSD
Aviation.........BJS
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
1132 PM CDT THU AUG 9 2012
.AVIATION...06Z TAFS FOR KOMA...KLNK AND KOFK. LIGHT NORTHEAST
WINDS WILL CONTINUE OVERNIGHT WITH CLEAR SKIES. COULD BE SOME
MVFR FOG AT KOMA/KOFK FROM ABOUT 10-14Z. NORTHEAST WINDS AROUND
8KTS AFTER THAT THROUGH THE REMAINDER OF FRIDAY WITH CUMULUS
CLOUDS DEVELOPING AGAIN AROUND 5000 FEET BY LATE MORNING THROUGH
THE AFTERNOON.
DEWALD
&&
.PREV DISCUSSION... /ISSUED 305 PM CDT THU AUG 9 2012/
DISCUSSION...
TEMPERATURES WILL PROVIDE THE PRIMARY FORECAST CHALLENGES THROUGH
FRIDAY NIGHT...THEN ATTENTION SHIFTS MORE TOWARD PRECIPITATION
CHANCES OVER THE WEEKEND.
MAIN FEATURES FROM THE 12Z UPPER AIR CHARTS THIS MORNING SHOWED THE
FOLLOWING. AT 300 MB...JETSTREAM CURVED NORTHEAST ACROSS THE PACIFIC
NORTHWEST INTO THE NORTHERN PLAINS...THEN TURNED SOUTHEAST INTO THE
OHIO VALLEY. A JET MAX OF AROUND 100 KNOTS WAS NOTED OVER MINNESOTA.
AT 500 MB...A RATHER IMPRESSIVE CLOSED LOW WAS OVER NORTHEAST
MINNESOTA WITH 12 HOUR HEIGHT FALLS OF 70 METERS NOTED AT KINL. THE
CENTER OF A MID LEVEL RIDGE WAS OVER THE FOUR CORNERS REGION.
COOLER AIR WAS PUSHING DOWN FROM MINNESOTA AND THE EASTERN DAKOTAS
AT 700 MB AND 850 MB.
SURFACE ANALYSIS EARLY THIS AFTERNOON INDICATED A RIDGE OF COOL HIGH
PRESSURE EXTENDING FROM ONTARIO AND MANITOBA DOWN INTO THE NORTHERN
AND WESTERN PLAINS. WINDS WERE MAINLY FROM THE NORTH OVER THE LOCAL
AREA. THAT SURFACE RIDGE WILL BUILD EASTWARD ACROSS THE FORECAST
AREA TONIGHT THROUGH FRIDAY NIGHT...WITH SEASONABLE TEMPERATURES AND
DRY CONDITIONS. EXPECT SOME PATCHY FOG TONIGHT AS WINDS DECREASE...
ESPECIALLY IN PARTS OF OUR CENTRAL AND EASTERN ZONES WHERE SPOTTY
RAIN FELL YESTERDAY AND TUESDAY. EXPECT THAT TO BURN OFF QUICKLY
FRIDAY...IF IT DEVELOPS...WITH SCATTERED CUMULUS MOST AREAS BY THE
AFTERNOON. HIGHS FRIDAY WILL BE IN THE 80S...CLOSE TO NAM MOS.
RETURN FLOW STRENGTHENS LATE FRIDAY NIGHT INTO SATURDAY AND
MODELS ARE IN GENERAL AGREEMENT WITH LARGE SCALE PATTERN. THEY
SHOW SOME 850-700 MB THETA E ADVECTION SPREADING FROM WEST TO EAST
ON SATURDAY. LARGE SCALE FORCING SEEMS WEAK AT BEST...SO KEPT POPS
ONLY AT 20 PERCENT AND TRIED TO CONFINE THOSE TO NORTHEAST
NEBRASKA SATURDAY. A MODEST SHORTWAVE TROUGH DOES MOVE ACROSS THE
PLAINS FOR SATURDAY NIGHT/EARLY SUNDAY...AND THIS IS PROBABLY OUR
BEST CHANCE FOR THUNDERSTORMS. THE 12Z GFS SEEMED WAY TOO GENEROUS
WITH QPF AND ITS OUTPUT WAS GENERALLY NOT USED. FAVORED A BLEND OF
THE NAM AND ECMWF FOR NOW...BUT SHOULD BE ABLE TO ADJUST THINGS
MORE AS WE GET CLOSER WITH 4 KM NAM AND HRRR MODELS. LINGERED SOME
LOW POPS INTO SUNDAY BASED ON CURRENT MODEL TIMING OF FORCING.
OTHERWISE...LOOK FOR DEAMPLIFICATION OF THE 500 MB PATTERN THROUGH
THE WEEKEND AND INTO EARLY NEXT WEEK AS RIDGE SHIFTS FROM THE FOUR
CORNERS REGION TO THE SOUTHERN PLAINS. AS HEIGHTS INCREASE BY MID
WEEK...HIGHS IN THE 90S WILL BECOME COMMON AGAIN.
MILLER
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
153 AM EDT FRI AUG 10 2012
.SYNOPSIS...
A TROUGH OF LOW PRESSURE OVER THE PIEDMONT THIS AFTERNOON THROUGH
FRIDAY WILL GIVE WAY TO A COLD FRONT ON SATURDAY. HIGH PRESSURE
WILL BUILD INTO THE AREA EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1045 PM THURSDAY...CONTINUED MAIN DILEMMA FOR THE OVERNIGHT
PERIOD WILL BE THE TIMING AND COVERAGE OF THE CONVECTIVE ACTIVITY
APPROACHING FROM THE SOUTHWEST. VARIOUS MODEL BUFR SOUNDINGS
INDICATE AN INCREASE IN MOISTURE THIS EVENING AND OVERNIGHT VIA PWS
REBOUNDING BACK OVER 2+ INCHES. WEAK MID LEVEL SHEARED VORT AND AN
UPPER LEVEL JET MAX TO TRACK NE ACROSS THE CAROLINAS TONIGHT...WITH
THE RIGHT REAR QUADRANT OF THIS UPPER JET AND SOURCE OF UPPER LEVEL
DIVERGENCE TO PUSH ACROSS OR AFFECT THE FA MAINLY AFTER MIDNIGHT
TONIGHT. THE RR QUAD WILL BE A FAVORED AREA OF UVVS AND AS A RESULT
WILL INCREASE POPS TO GOOD CHANCE OR POSSIBLY LIKELY LEADING TO BUT
MAINLY OCCURRING AFTER MIDNIGHT TONIGHT. THE DAYS HEATING COMBINED
WITH DYNAMICS ALOFT HAS HELPED CONVECTION REACH SVR CRITERIA WELL
UPSTREAM FROM THE FA. THE DAYS INSOLATION WILL BE DONE-WITH BY THE
TIME THE BULK OF THE PCPN PUSHES TO/ACROSS THE ILM CWA LATER
TONIGHT...AND AS A RESULT DO NOT ANTICIPATE PULSING SVR ACTIVITY.
HOWEVER...DO LIKE THE HEAVY RAIN/GUSTY WINDS TO SUFFIX AFTER THE
MENTIONING OF THE CONVECTION OVERNIGHT. EXPECT 20-30 MPH STORM
MOTIONS...WHICH SHOULD HELP LOWER THE FLOOD POTENTIAL. HOWEVER...IF
ACTIVITY BEGINS TO TRAIN...THEN WILL HAVE TO REVISIT THE FLOOD
ISSUE. AS FOR MIN TEMPS...WILL STAY ON THE HIGHER SIDE OF MOS
GUIDANCE DUE TO SKIES HAVING CLOUDED UP ALONG WITH THE POTENTIAL
MORNING OCCURRENCE OF PCPN.
&&
.SHORT TERM /SATURDAY THROUGH SATURDAY NIGHT/...
AS OF 2 PM THURSDAY...AN AMPLIFYING H5 TROUGH...APPROACHING COLD
FRONT AND PRECIPITABLE WATER SURGING ABOVE 2 INCHES WILL RESULT IN
AN UNSETTLED SHORT TERM PERIOD. THE FRONT IS EXPECTED TO STALL IN
THE VICINITY AS IT BECOMES ORIENTED WITH THE FLOW ALOFT. THUS THE
FORECAST INDICATES CHANCE TO LIKELY POPS THROUGH SATURDAY NIGHT.
FAVORED THE COOLER MET NUMBERS EACH DAY GIVEN THE EXPECTED CLOUD
COVER. THE CLOUD COVER COULD ALSO LIMIT DEEPER CONVECTION FROM
DEVELOPING...HOWEVER HEATING WILL LIKELY LEAD TO AT LEAST MODERATE
INSTABILITY.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
AS OF 2 PM THURSDAY...COLD FRONT WILL BE MOVING OFFSHORE WHILE
DISSIPATING AT THE START OF THE PERIOD. THIS WILL BRING AN END TO
PRECIP THROUGH SUNDAY AFTN AS DRIER AND COOLER AIR WORKS IN BEHIND
THIS BOUNDARY. FORECAST SOUNDINGS SUGGEST CLEARING WILL OCCUR
RAPIDLY DURING SUNDAY...BUT EVEN WITH AMPLE SUNSHINE...TEMPS WILL
STRUGGLE TO CLIMO AS SOME COOL ADVECTION OCCURS THROUGH MAX HEATING.
EXPECT TEMPS AT OR JUST BELOW 90 SUNDAY WITH MINS FALLING TO NEAR 70.
UPPER TROUGH WEAKENS AND SPINS OFF TO THE NORTHEAST AS SUBTLE
RIDGING DEVELOPS ACROSS THE SOUTHEAST. RISING 1000-500MB THICKNESSES
AND WARMING MID-LEVEL TEMPS WILL COMBINE WITH DRY W/NW FLOW TO
PREVENT WIDESPREAD CONVECTION MON EVEN WITH SLIGHTLY STEEPENED ML
LAPSE RATES. MOISTURE RETURN IS SLOW TO DEVELOP TUESDAY...BUT SOME
GUIDANCE INDICATING THAT A COASTAL TROUGH MAY HELP SPREAD SOME
MOISTURE TOWARDS THE COAST AND WILL BUMP POP TO CHC TUESDAY...ACROSS
THE EAST. TEMPS WILL REMAIN AROUND CLIMO...A FEW DEGREES EITHER SIDE
OF 90 AND 70.
FOR THE MID/LATE WEEK...BROAD TROUGHING REMAINS ACROSS THE EAST
WHILE WEAK IMPULSES MAY SPAWN AFTERNOON STORMS EACH DAY.
HOWEVER...WITH MID LEVEL DRY AIR PERSISTING...CONVECTION WILL BE
CAPPED AT SCHC/SILENT THIS FAR OUT IN TIME. A REINFORCING SHOT OF
COOL/DRY AIR MAY PUSH THROUGH THURSDAY AS UPPER VORT MOVES ACROSS
NEW ENGLAND WHICH WILL HELP KEEP TEMPS RIGHT AROUND CLIMO THROUGH
THE END OF THE PERIOD.
&&
.AVIATION /06Z FRIDAY THROUGH TUESDAY/...
AS OF 06Z...EXPECT VCTS AT ILM UNTIL AROUND 07Z. PRECIP ENDS BUT
REDEVELOPS COAST TERMS AFT 08Z-09Z. AT FLO/LBT TEMPO MVFR CIGS/VSBYS
IN BR 08-12Z. CONFIDENCE IN TIMING OF BR OR RW NOT REAL HIGH. TEMPO
MVFR LIKELY WITH PRECIP...BUT WILL NOT INCLUDE IFR DUE TO SCT NATURE
OF ACTIVITY ALTHOUGH SHORT TERM IFR PSBL IF CELL MOVES OVR A COAST
TERM. AS A SHORT WAVE APPROACHES PRECIP RE-DEVLPS BTWN COAST TERMS
AND INLAND TERMS BY 18Z...BUT CONFIDENCE LOW DUE TO SUBSIDENCE
BEHIND THIS MORNINGS ACTIVITY. IF DEVELOPMENT OCCURS IFR/TS WILL
OCCUR MAINLY COAST TERMS 18-00Z. LOW CONFIDENCE TS AT FLO/LBT 18-00Z.
EXTENDED OUTLOOK...CHANCE OF MORNING MVFR VSBYS IN BR WITH A CHANCE
OF SHOWERS AND THUNDERSTORMS THROUGH SUNDAY. VFR MONDAY.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 1045 PM THURSDAY...PROGGED SFC PRESSURE PATTERN AND TIGHTENING
GRADIENT...WILL YIELD WINDS FROM SSW-SW THIS EVENING AND
OVERNIGHT...ALONG WITH SPEEDS INCREASING FROM AROUND 15 KT...EXCEPT
15-20 KT FOR THE ILM NC WATERS. SIGNIFICANT SEAS ...MAINLY FROM WIND
DRIVEN 3-5 SECOND PERIOD WAVES...WILL BUILD TO 3 TO 5 FT NORTH OF
LITTLE RIVER INLET...AND 2 TO 4 FT SOUTH OF THE INLET. SEAS ARE
EXPECTED TO BUILD TO 4 TO 6 FT FOR THE ILM NC WATERS FRIDAY...WITH
SW WINDS 15-20 KT. STILL NOT ALL THAT CONFIDENT AT THE MOMENT WITH
REGARD TO RAISING A SCA/SCEC. IF DATA FROM TONIGHTS 00Z EARLY MODEL
RUNS INDICATE THIS INCREASED SCA POTENTIAL...MAY GO AHEAD AND ISSUE
A SCA OR SCEC AT THE LATE NIGHT UPDATE.
SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 2 PM THURSDAY...SOUTH-SOUTHWEST FETCH WILL BE IN PLACE THROUGH
THE BULK OF THE SHORT TERM PERIOD. IT APPEARS THE PRESSURE GRADIENT
WILL BE AT ITS GREATEST LATE FRIDAY AFTERNOON INTO THE EVENING. THE
FLOW WILL FINALLY BEGIN TO WEAKEN SATURDAY NIGHT WITH THE FRONT IN
THE VICINITY. SEAS MAY REACH MARGINAL SMALL CRAFT THRESHOLDS BY
FRIDAY EVENING...WITH EXERCISE CAUTION CONDITIONS EXPECTED DURING
THE MAJORITY OF THE PERIOD.
LONG TERM /SUNDAY THROUGH TUESDAY/...
AS OF 2 PM THURSDAY...PREDOMINANT SW FLOW TO PERSIST THROUGH THE
EXTENDED AS BERMUDA HIGH RIDGES IN FROM THE EAST. A FAIRLY WEAK
PRESSURE GRADIENT WILL EXIST HOWEVER...SO WINDS WILL BE AROUND 10
KTS OR LESS THROUGH MUCH OF THE PERIOD. THE LIGHT WINDS WILL PRODUCE
A 2-3FT/5SEC SW WIND CHOP WHICH WILL COMBINE WITH A 2FT/9SEC SE
SWELL TO PRODUCE OVERALL WAVE HEIGHTS OF 2-3 FT.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 6 AM THIS MORNING TO 9 AM EDT
SATURDAY FOR AMZ250-252.
&&
$$
AVIATION...MRR
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
601 AM EDT FRI AUG 10 2012
.SYNOPSIS...
A SLOW MOVING COLD FRONT WILL APPROACH THE FORECAST AREA FROM THE
NORTHWEST THROUGH TONIGHT. THE FRONT WILL BECOME DIFFUSE SATURDAY.
&&
.NEAR TERM /THROUGH TODAY/...
MOISTURE WILL BE HIGH AHEAD OF THE SLOW MOVING COLD FRONT TODAY.
EXPECT NUMEROUS SHOWERS AND THUNDERSTORMS MAINLY ASSOCIATED WITH
THE H85 JET. THE RAP AND NAM INDICATE THE JET WILL MAINLY AFFECT
THE FORECAST AREA EARLY TODAY. HOWEVER...CONTINUED HIGH MOISTURE
AHEAD OF THE FRONT AND DIURNAL HEATING SUPPORTS ADDITIONAL SHOWERS
AND THUNDERSTORMS LATER TODAY. LEANED TOWARD THE HIGHER GUIDANCE
POPS. CLOUDINESS SHOULD LIMIT INSTABILITY. THE NAM/S FORECAST OF
WEAK INSTABILITY APPEARS REASONABLE. IF SIGNIFICANT BREAKS AND
STRONG HEATING DOES OCCUR THEN THERE WILL BE ENOUGH SHEAR FOR A
FEW SEVERE THUNDERSTORMS. THE NAM SHOWS H85 WINDS NEAR 30 KNOTS
MAINLY EARLY TODAY. BOTH THE NAM AND GFS SHOW RAINFALL AMOUNTS
LESS THAN ONE- QUARTER OF AN INCH AND THESE GENERAL VALUES MAY BE
CORRECT SINCE THE H85 JET MAXIMUM SHOULD BE NORTHEAST OF THE
FORECAST AREA WHICH SHOULD LIMIT CONVERGENCE. HOWEVER...THERE WILL
BE A THREAT OF VERY HEAVY RAIN BECAUSE OF PRECIPITABLE WATER
VALUES AROUND 2 INCHES. ALSO...EXPECT 1000-500 MB THICKNESSES NEAR
574 WHICH IS THE PREFERRED VALUE FOR HEAVY RAIN IN AUGUST. USED
THE GUIDANCE CONSENSUS FOR THE TEMPERATURE FORECAST.
&&
.SHORT TERM /TONIGHT THROUGH SATURDAY NIGHT/...
MOISTURE AND CONVERGENCE ASSOCIATED WITH THE SLOW MOVING FRONT
SUPPORTS SHOWERS AND THUNDERSTORMS TONIGHT. HOWEVER...INSTABILITY
SHOULD BE LIMITED BY PREVIOUS CONVECTION AND DIURNAL COOLING.
FORECASTED POPS OF LIKELY EARLY AND CHANCE LATE. THE NAM AND GFS
SHOW THE FRONT LINGERING NEAR THE FORECAST AREA SATURDAY AND
SATURDAY NIGHT BUT DEEPER MOISTURE APPEARS TO SHIFT A LITTLE EAST
OF THE FORECAST AREA SATURDAY. THE NAM AND GFS MOS SUPPORT CHANCE
POPS. USED THE GUIDANCE CONSENSUS FOR THE TEMPERATURE FORECAST
THROUGH THE PERIOD.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
THE GFS SHOWS RIDGING TO THE SOUTH WITH LEE-SIDE TROUGHING IN THE
FORECAST AREA DURING MUCH OF THE EXTENDED PERIOD. THE PATTERN
SUPPORTS MAINLY DIURNAL SCATTERED THUNDERSTORMS. THE GFS ENSEMBLE
MEANS SUPPORT SLIGHT CHANCE OF CHANCE POPS. EXPECT TEMPERATURES NEAR
CLIMATOLOGY WITH LOWS IN THE LOWER 70S AND HIGHS IN THE LOWERS 90S.
&&
.AVIATION /10Z FRIDAY THROUGH TUESDAY/...
LOW LEVEL JET AFFECTING THE AREA TODAY. SOUTH WIND 5-10 KT THIS
MORNING WILL FAVOR STRATUS CLOUDS RATHER THAN FOG. GUIDANCE HAVE
COME INTO AGREEMENT WITH LIFR/IFR CIGS ACROSS THE TAF SITES THROUGH
14-15Z. SO CONFIDENCE IS HIGH. COULD EVEN SEE A FEW SHOWERS EARLY
THIS MORNING. EXPECT IMPROVING CONDITIONS BY 15Z-16Z. SOUTHWEST
WINDS INCREASING TO 10-15KT BY MIDDAY WITH GUSTS NEAR 20 KNOTS.
WIDESPREAD SHOWERS AND THUNDERSTORMS EXPECTED AGAIN THIS AFTERNOON
INTO TONIGHT.
EXTENDED AVIATION OUTLOOK...AN UNSETTLED WEATHER WILL PERSIST
THROUGH SUNDAY. A COLD FRONT WILL MOVE SLOWLY THROUGH THE REGION
FRIDAY THROUGH SUNDAY...THEREBY HOLDING A GOOD CHANCE FOR CONVECTION.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS NASHVILLE TN
1158 PM CDT THU AUG 9 2012
.UPDATE...FOR 06Z AVIATION DISCUSSION.
&&
.AVIATION...06Z AVIATION DISCUSSION.
UNCERTAINTIES...SFC FRONTAL MOVEMENT IMPACTS. AS SFC FRONT MOVES
CLOSER/EVENTUALLY THRU CKV/BNA...EXPECT SOME MOISTURE POOLING IN
ITS VICINITY...MENTIONED MVFR FOG/CEILINGS...TEMPO IFR CSV...BUT
EVEN WITH POSSIBLE SHORT WAVE PASSAGE IN UPPER LEVEL FLOW AIDING...
WILL JUST MENTION VCSH AT CKV/BNA. FRONT SHOULD BE W OF CSV THRU
AROUND 10/18Z...AND BELIEVE WITH DIURNAL INFLUENCES KICKING IN...
THAT CB/VCTS TSTM CSV APPROPRIATE. A DRYING AIRMASS SHOULD ESTABLISH
ITSELF ACROSS THE MID STATE BY 11/00Z TO SUPPORT SKC CONDITIONS.
&&
.PREV DISCUSSION.../ISSUED 1011 PM CDT THU AUG 9 2012/
UPDATE...
OTHER THAN THE ISOL CONVECTION OVER WESTERN MIDDLE TN...NOT MUCH
GOING ON. BOUNDARY STILL LOCATED A GOOD DISTANCE TO OUR NW.
NUMERICAL POPS ARE QUITE LOW THROUGH 12Z. HRRR NOW SHOWING SOME
REDEVELOPMENT WITH THE FRONTAL BOUNDARY AFT 08Z OR SO. PRESSURE
RISES ARE FAIRLY STRONG NORTH OF THE FRONTAL BOUNDARY.
THUS...BOUNDARY SHOULD STILL BE ON THE APPROACH THROUGH 12Z.
WILL GO AHEAD AND LOWER POPS TO THE 30-40 PERCENT RANGE FOR THE
DURATION. HRRR DOES MAKE A COMEBACK WITH THE CONVECTION BUT
PRIMARILY IS SERVING AS THE LONE MODEL...AND EVEN IF THE HRRR PANS
OUT...THE ACTIVITY DOES NOT LOOK ALL THAT ORGANIZED.
FOR THE UPDATE WILL LOWER POPS. UPDATE OUT SHORTLY.
PREV DISCUSSION.../ISSUED 703 PM CDT THU AUG 9 2012/
UPDATE...FOR 00Z AVIATION DISCUSSION.
AVIATION...00Z AVIATION DISCUSSION.
UNCERTAINTIES...SFC FRONTAL MOVEMENT IMPACTS. CONVECTION TO OUR
NW AHEAD OF FRONT MAINLY DISSIPATED...AND WITH AN OVERALL DRIER
AIRMASS IN PLACE ACROSS THE MID STATE PER MORNING`S
CONVECTION...PCPN CHANCES SLIGHT AT BEST THRU 10/10Z AND WILL NOT
MENTION. AS SFC FRONT MOVES CLOSER/EVENTUALLY THRU
CKV/BNA...EXPECT SOME MOISTURE POOLING IN ITS VICINITY...MENTIONED
MVFR FOG/CEILINGS...TEMPO IFR CSV...BUT EVEN WITH POSSIBLE SHORT
WAVE PASSAGE IN UPPER LEVEL FLOW AIDING...JUST DOUBT WITH ANY
DIURNAL INFLUENCES NOT YET ESTABLISHED...PCPN WILL OCCUR. FRONT
SHOULD BE W OF CSV THRU AROUND 10/18Z...AND BELIEVE WITH DIURNAL
INFLUENCES KICKING IN...THAT CB/VCTS TSTM CSV APPROPRIATE.
PREV DISCUSSION.../ISSUED 602 PM CDT THU AUG 9 2012/
UPDATE...
NOT IMPRESSED WITH THE CHANCES FOR CONVECTION OVERNIGHT. ONLY
BULLISH TRENDS I SEE ARE WITH THE WRF AND THE FROPA WHICH IS
EXPECTED AT 12Z. OTW...UPPER DYNAMICS LOOKING WEAK WITH AN OVERALL
DECREASE IN MOISTURE DEPTH FROM 00Z TO 06Z. HRRR SHOWS ZILCH
THROUGH 6Z AND UPPER DIVERGENCE QUITE WEAK THROUGH 12Z ON THE GFS
AND NAM. I WILL GO AHEAD AND UPDATE GRIDS AD KNOCK POPS DOWN
PRIOR TO 06Z. AFT 06Z...WILL KEEP THE LIKELY POPS GOING ACROSS THE
NORTH BUT THIS MAY NEED A DOWNWARD YANK AS WELL LATER IN THIS
SHIFT.
REMAINDER OF FCST LOOKS TO BE IN GOOD SHAPE. NO MENTION OF FOG
CURRENTLY AND I SEE NO REASON TO ADD ANY AS TOVERS REMAIN NEAR TO
ABOVE 0. MIN TEMP FCST LOOKS TO BE IN GOOD SHAPE. UPDATE OUT SHORTLY.
PREV DISCUSSION.../ISSUED 340 PM CDT THU AUG 9 2012/
SHORT TERM...SHOWERS AND CLOUDS THAT STILL LINGERED ALONG THE
CUMBERLAND PLATEAU AT MID-AFTERNOON WERE HELPING TO PRODUCE A
SIGNIFICANT TEMPERATURE GRADIENT ACROSS THE MID STATE. AT 300
PM...TEMPERATURES RANGED FROM THE UPPER 60S AT CSV TO THE UPPER
80S OVER OUR MOST WESTERN COUNTIES.
WITH SHOWERS DEPARTING OUR AREA, FROM THE PLATEAU, WE NOW TURN OUR
EYES TO THE WEST, WHERE NEW THUNDERSTORMS WERE POPPING UP IN THE
AFTERNOON HEAT, OVER SOUTHWESTERN KENTUCKY. THESE STORMS WERE ALSO
OCCURRING ALONG THE EDGE OF A BAND OF MID-T0-UPPER LEVEL DRYING
THAT EXTENDED FROM SOUTHERN PARTS OF INDIANA AND ILLINOIS, ACROSS
SOUTHEAST MISSOURI INTO CENTRAL ARKANSAS. WITH THE POSSIBILITY OF
DRY AIR ENTRAINMENT AT THE MID LEVELS, EXPECT SOME GUSTY
DOWNBURSTS TO BE POSSIBLE WITH THESE STORMS AS THEY ADVANCE INTO
NORTHWESTERN MIDDLE TENNESSEE LATE THIS AFTERNOON AND EVENING.
AFTER THE INITIAL CONVECTION THIS EVENING, THAT DEVELOPS MAINLY
OVER THE NORTHWEST, BELIEVE WE WILL SEE MORE THUNDERSTORM
DEVELOPMENT LATER TONIGHT, AS UPPER TROUGH DEEPENS OVER THE OHIO
RIVER VALLEY, ENERGIZING THE SLEEPY STATIONARY FRONT JUST WEST OF
PADUCAH, AND BRINGING IT EASTWARD AS A COLD FRONT.
EXPECT THE COLD FRONT TO BE NEAR A BWG-BNA-WAYNESBORO LINE BY 12Z
FRIDAY, PUSHING TO NR A MSL-LIVINGSTON LINE BY 18Z, AND OFF THE
CUMBERLAND PLATEAU BY LATE FRIDAY AFTERNOON.
SPC HAS ALL OF OUR AREA IN A SLIGHT RISK FOR SEVERE THUNDERSTORMS
THROUGH 12Z FRIDAY, AS THE FRONT PUSHES IN, AND EXPECT TO SEE
SIMILAR STORMS TO THE ONES WE HAD THIS MORNING...VERY WET AND
JUICY (WITH TORRENTIAL DOWNPOURS) ALONG WITH THE POSSIBILITY FOR
STRONG, GUSTY DOWNBURST WINDS.
EXPECT SHOWERS AND STORMS TO FINALLY PUSH EAST OF THE MID STATE FRIDAY
EVENING, WITH SEVERAL DAYS OF DRY AND AUTUMN-LIKE CONDITIONS TO
FOLLOW OVER THE WEEKEND. EXPECT AFTERNOON DEW POINTS IN THE 50S
BOTH SATURDAY AND SUNDAY, WITH DAYTIME HIGHS MAINLY IN THE MIDDLE
80S. MANY PLACES WILL LIKELY SEE LOW TEMPERATURES DROP INTO THE
MID TO UPPER 50S SUNDAY MORNING.
LONG TERM...AFTER OUR DRY SPELL OVER THE WEEKEND, EXPECT
NORTHWEST FLOW TO BECOME MORE ZONAL, WITH TWO OR THREE UPPER LEVEL
SHORTWAVES LIKELY TO TRAVERSE THE AREA NEXT WEEK. THE TIMING OF
THESE IMPULSES, OF COURSE, IS VERY DIFFICULT. IT`S ALSO DIFFICULT
TO KNOW HOW MUCH SHRA/TSRA ACTIVITY EACH ONE WITH BRING WITH IT.
THEREFORE, HAVE PAINTED POPS WITH A BROAD BRUSH FOR MOST OF NEXT
WEEK, WITH A 20% POP MAKING REPEATED ONSTAGE APPEARANCES.
TEMPERATURES WILL WARM BACK TO AROUND 90 DEGREES OR IN THE LOWER
90S FOR AREAS WEST OF THE CUMBERLAND PLATEAU, WITH TEMPS FORECAST
TO BE MAINLY IN THE MIDDLE 80S ALONG THE PLATEAU ITSELF.
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
31
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
345 AM EDT FRI AUG 10 2012
.SYNOPSIS...
A STRONG UPPER LEVEL TROUGH WILL PASS INTO THE GREAT LAKES
TODAY...DRAGGING A COLD FRONT ACROSS THE REGION THIS EVENING.
THIS WILL RESULT IN ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS
THIS AFTERNOON AND EVENING...WITH A FEW STORMS BECOMING STRONG TO
SEVERE. ONCE THE COLD FRONT MOVES EAST OF THE AREA LATE
TONIGHT...HIGH PRESSURE WILL BUILD IN...BRINGING COOLER AND DRIER
AIR IN FOR THE REMAINDER OF THE WEEKEND AND THE EARLY PART OF NEXT
WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 315 AM EDT FRIDAY...
MAIN CONCERN TODAY WITH THE DEGREE OF POSSIBLE RENEWED CONVECTION
LATER ON AS THE UPPER LOW TO THE NW PROPELS A STRONG COLD FRONT TO
ALONG THE WESTERN SLOPES THIS EVENING AND EAST OF THE BLUE RIDGE
OVERNIGHT. AGAIN ONE OF THE MAIN FACTORS IS WITH JUST HOW MUCH
DEEP INSTABILITY CAN BE GENERATED THIS AFTERNOON IN THE WAKE OF
THE CURRENT MVC THAT WILL EXIT THE CWA BY DAYBREAK. THIS FEATURE
AND ITS CONVECTION HAVE BASICALLY REMOVED ANY LINGERING CAPE FROM
THU EVENING AND WILL NEED A PERIOD OF STRONG HEATING TO REGENERATE
ENOUGH INSTABILITY FOR A MORE WIDESPREAD SEVERE THREAT. LATEST
FCST SOUNDINGS DO SHOW WIND FIELDS STRENGTHENING/BACKING ALOFT
AHEAD OF THE UPSTREAM TROF THRU THIS EVENING SUGGESTING POTENTIAL
FOR BANDS OF DEEPER CONVECTION THAT MAY EVENTUALLY LINE UP ESPCLY
OUT EAST BY THIS EVENING. HOWEVER LATEST MODELS REMAIN SPREAD
ACROSS THE BOARD WITH TIMING AND LOCATION ISSUES OF PRE- FRONTAL
LIFT PER SLOWNESS IN INITIALIZING WITH THE CURRENT REMNANT MCS
ATTM. APPEARS BEST SOLUTION IS TO LEAN TOWARD THE LATEST HRRR AND
GO WITH DEVELOPMENT OF MULTICELLULAR BANDS OVER THE MOUNTAINS BY
EARLY AFTERNOON PER UNIDIRECTIONAL FLOW AND THETA-E RIDGING...WITH
THIS COVERAGE OR ANOTHER LINE GRADUALLY ORGANIZING UPON HEADING
EAST INTO BETTER INSTABILITY OUT EAST THRU EARLY EVENING. THIS
AGAIN BASED ON AT LEAST SOME HEATING AS SUGGESTED BY THE LATEST
NAM WHICH BREAKS OPEN THE MID DECK LATER THIS MORNING AHEAD OF THE
BOUNDARY. THUS HAVE ADJUSTED POPS TO REFLECT A BREAK IN COVERAGE
PER WEAK SUBSIDENCE IN BEHIND THE PASSING VORT EARLY THIS
MORNING...INCREASING TO LIKELY/CAT POPS WEST EARLY/MID
AFTERNOON...THEN TRANSLATING EAST INTO EARLY THIS EVENING. THINK
COVERAGE MOVING ENOUGH TO PRECLUDE A FLASH FLOOD WATCH BUT
CERTAINLY A WIND THREAT GIVEN DECENT FCST DCAPES WHICH WILL COVER
IN THE HWO PER SWODY1 SLIGHT RISK. WILL STAY ON THE WARM SIDE OF
MOS TEMPS TODAY AS THINKING SOME INSOLATION BUT IF CLOUDS HOLD AND
CONVECTION FASTER THEN HIGH BUST POTENTIAL REMAINS.
EXPECT MAIN AXIS OF CONVECTION TO BE EAST OF THE MOUNTAINS THIS
EVENING AND MAY TAKE SOME TIME TO EXIT THE PIEDMONT AS ANOTHER WEAK
IMPULSE RIDES UP THE FRONT. THINK SEVERE POTENTIAL LIMITED BEHIND
THE INIT WAVE OF STORMS BUT LINGERING HEAVY RAIN THREAT COULD
PERSIST WHILE SHOWERS BECOME WIDELY SCATTERED OR END BEHIND THE
BOUNDARY OVER THE MOUNTAINS OVERNIGHT. THEREFORE DID DECREASE POPS
A BIT FASTER WEST THINKING CONVECTION WILL HELP TAKE DEEP MOISTURE
TO THE EAST LATE...BUT LIKELY STILL LOTS OF CLOUDS AS THE UPPER
FLOW REMAINS SW AND PARALLEL TO THE SFC FRONT. MAIN PUSH OF 85H
COOL ADVECTION WILL STILL BE WEST OF THE BLUE RIDGE LATE TONIGHT
SO KEEPING TEMPS WARMER OUT EAST AND NOT QUITE AS COOL MOUNTAINS
PER CLOUD COVER. OTRW RANGE OF LOWS FROM AROUND 60 FAR WEST TO
65-70 SE LOOKS BEST.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 300 AM EDT FRIDAY...
SHORTWAVE PIVOTS ACROSS THE CENTRAL APPALACHIANS SATURDAY AFTERNOON.
THIS WILL KEEP THE THREAT OF SHOWERS AND ISOLATED THUNDERSTORMS
GOING IN THE EAST WITH COOL POOL ALOFT. 8H TEMPS COOL TO +14C...SO
WITH SOME CLOUD COVER FROM THE COLDER AIR ALOFT...EXPECT HIGHS
CLOSE TO THE ADJMETBC WITH READINGS FROM THE MID 70S IN THE
MOUNTAINS TO THE MID 80S IN THE SOUTHEAST.
DRIER AIR WILL FINALLY WORKS IN FROM THE NORTHWEST SATURDAY NIGHT
INTO SUNDAY WITH DEWPOINTS DROPPING INTO THE UPPER 40S/LOWER 50S IN
THE HIGHER ELEVATIONS WITH MID 50S VALLEYS. THE PIEDMONT COULD SEE
SOME 50S DEWPOINTS BUT HARD TO DISPLACE THE HUMID AIRMASS ACROSS THE
CAROLINAS AS THE FLOW ALOFT STAYS WSW. PLAYED LOW TEMPERATURES
SATURDAY NIGHT FROM THE LOWER 50S IN THE MOUNTAINS TO THE LOWER 60S
IN THE EAST.
ON SUNDAY...TEMPERATURES MODERATE WITH WSW FLOW AND MORE SUNSHINE.
HEIGHTS/8H TEMPERATURES INCREASE AGAIN...HIGHS SUNDAY RETURNING TO
AROUND 80 DEGREES IN THE MOUNTAINS TO THE UPPER 80S IN THE
SOUTHEAST. LEANED TOWARDS THE ECMWFBC FOR SUNDAY NIGHT LOW
TEMPERATURES WITH VALUES FROM THE MID 50S IN THE WEST TO THE MID 60S
IN THE EAST.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
AS OF 400 PM EDT THURSDAY...
DRIER AIRMASS WILL BE DISPLACED DURING THIS PERIOD AS THE FRONT FROM
THE SHORT TERM PERIOD STALLS ACROSS THE CAROLINAS/TN VALLEY THEN
SHIFTS SLOWLY NORTH BY TUESDAY AS ANOTHER WAVE OF LOW PRESSURE
SHIFTS ACROSS IT FROM THE LOWER MISSOURI VALLEY INTO THE VA
TIDEWATER FROM MON-TUE. THIS FRONT WILL BE CLOSE ENOUGH THAT
SHOWER/TSRA CHANCES INCREASE AGAIN BY TUESDAY. ONCE THE
SHORTWAVE/ASSOCIATED SFC LOW PASS TUESDAY AFTERNOON...WEAK HIGH
PRESSURE WILL PUSH THE FRONT BACK SOUTH INTO THE GA/SC BY WEDNESDAY
AND THE AIRMASS DRIES OUT SOME...BUT THE UPPER TROUGH IS NOT AS DEEP
AS THIS WEEKENDS. OVERALL...THE TEMPS NEXT WEEK WILL AVERAGE
80S/LOWER 90S FOR HIGHS AND 60S FOR LOWS.
&&
.AVIATION /08Z FRIDAY THROUGH TUESDAY/...
AS OF 105 AM EDT FRIDAY...
AXIS OF CONVECTION CONTINUES TO WORK NE JUST EAST OF THE BLUE
RIDGE ATTM AND EXPECT THIS COVERAGE TO AFFECT KDAN AND KLYH FOR A
FEW MORE HOURS WITH MVFR/IFR CONDITIONS. ELSW A FEW ADDED ISOLATED
SHRA POSSIBLE OVERNIGHT OTRW LOOKING AT MAINLY VFR BEFORE FOG
FORMATION SETS IN PENDING JUST HOW FAST THE MID DECK CANOPY ERODES
BY DAYBREAK. APPEARS THE NORMALLY FOGGY LOCATIONS SUCH AS KLWB
WILL SEE IFR/LIFR BY DAWN WITH MVFR/IFR POSSIBLE AT KBCB. EASTERN
AREAS MAY ALSO SEE SOME MVFR FOG DEVELOP IN THE WAKE OF THE
CURRENT SHRA/TSRA SO INCLUDING SOME LOWER VSBYS/CIGS EARLY FRIDAY.
SHOWER AND THUNDERSTORMS WILL INCREASE LATE FRIDAY MORNING AND
EARLY AFTERNOON AS A DEEP UPPER LEVEL TROUGH APPROACHES THE
AREA...WITH AN ASSOCIATED COLD FRONT ENTERING THE WESTERN PART OF
THE FORECAST AREA TOWARD THE END OF THE TAF PERIOD. WILL BE
LOOKING AT A FEW STRONG STORMS TO START THE AFTERNOON...AND EXPECT
THAT THESE STORMS WILL FORM INTO A LINE OR TWO JUST AHEAD OF THE
COLD FRONT AS IT ENTERS THE PIEDMONT REGION DURING EARLY EVENING.
THUNDERSTORM ACTIVITY IS EXPECTED TO END ACROSS THE AREA AS THE
FRONT EXITS TO THE EAST DURING LATE EVENING...AT WHICH POINT DRIER
AIR ASSOCIATED WITH HIGH PRESSURE WILL RESULT IN VFR CONDITIONS
HEADING INTO THE EARLY PART ON NEXT WEEK.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...JH/NF
NEAR TERM...JH
SHORT TERM...KK
LONG TERM...WP
AVIATION...JH/KM/NF
SOUTHWEST CALIFORNIA AREA FORECAST DISCUSSION
NWS LOS ANGELES/OXNARD CA
445 AM PDT FRI AUG 10 2012
...UPDATED AVIATION DISCUSSION...
.SYNOPSIS...
A HOT AIR MASS WILL REMAIN IN PLACE THROUGH THE WEEKEND DUE TO
HIGH PRESSURE OVER THE REGION. ISOLATED THUNDERSTORMS ARE
POSSIBLE FOR THE VENTURA AND LOS ANGELES COUNTY MOUNTAINS AND
ANTELOPE VALLEY AS MONSOONAL MOISTURE OVER THE AREA. A TROUGH OF
LOW PRESSURE IS EXPECTED TO COOL TEMPERATURES CLOSER TO NORMAL
EARLY NEXT WEEK.
&&
.SHORT TERM (TODAY-SUNDAY)...
STRONG HIGH PRESSURE ALOFT REMAINS OVER THE REGION THIS MORNING
AS SOUTHEAST FLOW ALOFT ESTABLISHES. AT THE SURFACE...A THERMAL
TROUGH REMAIN OFFSHORE SOUTH OF POINT CONCEPTION AND IS SHIFT
ONSHORE NORTH OF POINT CONCEPTION. WITH THE SURFACE TROUGH
OFFSHORE...ANOTHER HOT DAY IS ON TAP SOUTH OF POINT CONCEPTION.
NORTH OF POINT CONCEPTION...INCREASING ONSHORE GRADIENTS SHOULD
PROVIDE SOME COOLING TODAY. AN EXCESSIVE HEAT WARNING REMAINS IN
EFFECT FOR THE LOS ANGELES AND VENTURA COUNTY VALLEYS AND
MOUNTAINS AND THE SANTA BARBARA COUNTY MOUNTAINS THROUGH THIS
EVENING. HEAT INDEX VALUES WILL BE NEAR DANGEROUS LEVELS AGAIN
TODAY OVER THESE AREAS.
THE MAIN CONCERN FOR THE TEMPERATURE FORECAST IS THE INCREASING
MID-LEVEL MOISTURE OCCURRING THIS MORNING. SOME COOLING CLOUD
TOPS ARE OCCURRING THIS MORNING AND THE CLOUD MASS IS EXPANDING
OVER THE AREA THIS MORNING. THIS COULD BE THE MAIN PROBLEM FOR
TODAY BEING THE WARMEST DAY OF THE WEEK AS PREVIOUSLY ADVERTISED.
IN ADDITION...SURFACE GRADIENTS TRENDS ARE STARTING TO REVERSE AND
BECOME MORE STRONGLY ONSHORE. WITH THESE TWO FACTORS IN
MIND...TEMPERATURES WERE COOLED SLIGHTLY AS THE AIR MASS COULD
COOL SLIGHTLY AS A RESULT.
THE CLOUD MASS OVER LOS ANGELES COUNTY THIS MORNING IS BEING
MONITORED CLOSELY WITH MODEL SOLUTIONS HANDLING THE MOISTURE
REASONABLY...BUT THE THERMAL PATTERN ALOFT SEEMS QUESTIONABLE.
GOES SATELLITE IMAGERY PLACES CLOUDS TOPS BETWEEN 20 AND 30 KFT
THIS MORNING WITH CLOUD TOPS COOLING...YET MODEL SOLUTIONS ALL
INDICATE TEMPERATURES INCREASING ALOFT. SOME CONCERN IS PLACED
WITH CLOUD MASS POSSIBLY BECOMING CONVECTIVE AS THE MORNING
PROGRESSES AND POPS NEEDING TO BE ADDED FOR THE COASTS AND
VALLEYS FOR TODAY. RAP MODEL SOLUTIONS SUGGEST SOME MID-LEVEL
CAPE DEVELOPING LATER THIS MORNING AND SOME POSITIVE OMEGA
OCCURRING IN THE LOWER LEVELS OF THE ATMOSPHERE. FOR NOW...THE
BEST APPROACH IS TO MONITOR THE SITUATION FOR THE POSSIBILITY OF
SHOWERS DEVELOPING THEN UPDATE AS NECESSARY.
THE AIR MASS WILL CONTINUE TO MOISTEN THROUGH THE WEEKEND AND
COOL AS A MONSOONAL FLOW PATTERN MATURES OVER THE AREA. THE
CHANCES FOR SHOWERS AND THUNDERSTORMS WILL INCREASE SLIGHTLY FOR
SATURDAY AS MOISTURE INCREASES OVER THE AREA. THE HEAT WAVE WILL
SEE SOME REPRIEVE BUT IT WILL REMAIN QUITE WARM UNTIL SOUTHWEST
FLOW ALOFT ESTABLISHES OVER THE AREA EARLY NEXT WEEK.
.LONG TERM (MONDAY-THURSDAY)...
SOUTHWEST FLOW ALOFT SHOULD ESTABLISH OVER THE AREA BETWEEN SUNDAY
AND MONDAY AND BRING A COOLER AND DRIER AIR MASS TO THE AREA.
ONSHORE FLOW SHOULD INCREASE AND ALLOW FOR A STRONGER SEA BREEZE
EACH DAY...WITH A COOLING TREND PERSISTING INTO THURSDAY. SOME
LOWER VALLEY INTRUSION OF THE MARINE LAYER CLOUDS IS POSSIBLE
BETWEEN MONDAY NIGHT AND THURSDAY.
&&
.AVIATION...10/1145Z.
HIGH CONFIDENCE FOR VFR CONDITIONS ARE EXPECTED AT ALL INLAND
TERMINALS. AT COASTAL TERMINALS SOUTH OF POINT CONCEPTION...THERE IS
A 30 PERCENT CHANCE OF LIFR CONDITIONS AT COASTAL TERMINALS BETWEEN
12Z AND 16Z. NORTH OF POINT CONCEPTION...VLIFR TO LIFR CONDITIONS
WILL PERSIST THROUGH AT LEAST 14Z...THEN GRADUALLY IMPROVE TO VFR
THROUGH 17Z.
KLAX...VFR CONDITIONS ARE EXPECTED THROUGHOUT THE PERIOD. THERE IS A
20 PERCENT CHANCE OF VLIFR TO LIFR CONDITIONS BETWEEN 12Z AND 15Z.
KBUR...VFR CONDITIONS ARE EXPECTED THROUGHOUT THE PERIOD WITH NO
WIND ISSUES.
&&
.LOX WATCHES/WARNINGS/ADVISORIES...
EXCESSIVE HEAT WARNING (SEE LAXNPWLOX).
SMALL CRAFT ADVISORY (SEE LAXMWWLOX).
SPECIAL WEATHER STATEMENT (SEE LAXSPSLOX).
&&
$$
PUBLIC...HALL
AVIATION...CK
SYNOPSIS...B/HALL
WWW.WEATHER.GOV/LOSANGELES
SOUTHWEST CALIFORNIA AREA FORECAST DISCUSSION
NWS LOS ANGELES/OXNARD CA
421 AM PDT FRI AUG 10 2012
.SYNOPSIS...
A HOT AIR MASS WILL REMAIN IN PLACE THROUGH THE WEEKEND DUE TO
HIGH PRESSURE OVER THE REGION. ISOLATED THUNDERSTORMS ARE
POSSIBLE FOR THE VENTURA AND LOS ANGELES COUNTY MOUNTAINS AND
ANTELOPE VALLEY AS MONSOONAL MOISTURE OVER THE AREA. A TROUGH OF
LOW PRESSURE IS EXPECTED TO COOL TEMPERATURES CLOSER TO NORMAL
EARLY NEXT WEEK.
&&
.SHORT TERM (TODAY-SUNDAY)...
STRONG HIGH PRESSURE ALOFT REMAINS OVER THE REGION THIS MORNING
AS SOUTHEAST FLOW ALOFT ESTABLISHES. AT THE SURFACE...A THERMAL
TROUGH REMAIN OFFSHORE SOUTH OF POINT CONCEPTION AND IS SHIFT
ONSHORE NORTH OF POINT CONCEPTION. WITH THE SURFACE TROUGH
OFFSHORE...ANOTHER HOT DAY IS ON TAP SOUTH OF POINT CONCEPTION.
NORTH OF POINT CONCEPTION...INCREASING ONSHORE GRADIENTS SHOULD
PROVIDE SOME COOLING TODAY. AN EXCESSIVE HEAT WARNING REMAINS IN
EFFECT FOR THE LOS ANGELES AND VENTURA COUNTY VALLEYS AND
MOUNTAINS AND THE SANTA BARBARA COUNTY MOUNTAINS THROUGH THIS
EVENING. HEAT INDEX VALUES WILL BE NEAR DANGEROUS LEVELS AGAIN
TODAY OVER THESE AREAS.
THE MAIN CONCERN FOR THE TEMPERATURE FORECAST IS THE INCREASING
MID-LEVEL MOISTURE OCCURRING THIS MORNING. SOME COOLING CLOUD
TOPS ARE OCCURRING THIS MORNING AND THE CLOUD MASS IS EXPANDING
OVER THE AREA THIS MORNING. THIS COULD BE THE MAIN PROBLEM FOR
TODAY BEING THE WARMEST DAY OF THE WEEK AS PREVIOUSLY ADVERTISED.
IN ADDITION...SURFACE GRADIENTS TRENDS ARE STARTING TO REVERSE AND
BECOME MORE STRONGLY ONSHORE. WITH THESE TWO FACTORS IN
MIND...TEMPERATURES WERE COOLED SLIGHTLY AS THE AIR MASS COULD
COOL SLIGHTLY AS A RESULT.
THE CLOUD MASS OVER LOS ANGELES COUNTY THIS MORNING IS BEING
MONITORED CLOSELY WITH MODEL SOLUTIONS HANDLING THE MOISTURE
REASONABLY...BUT THE THERMAL PATTERN ALOFT SEEMS QUESTIONABLE.
GOES SATELLITE IMAGERY PLACES CLOUDS TOPS BETWEEN 20 AND 30 KFT
THIS MORNING WITH CLOUD TOPS COOLING...YET MODEL SOLUTIONS ALL
INDICATE TEMPERATURES INCREASING ALOFT. SOME CONCERN IS PLACED
WITH CLOUD MASS POSSIBLY BECOMING CONVECTIVE AS THE MORNING
PROGRESSES AND POPS NEEDING TO BE ADDED FOR THE COASTS AND
VALLEYS FOR TODAY. RAP MODEL SOLUTIONS SUGGEST SOME MID-LEVEL
CAPE DEVELOPING LATER THIS MORNING AND SOME POSITIVE OMEGA
OCCURRING IN THE LOWER LEVELS OF THE ATMOSPHERE. FOR NOW...THE
BEST APPROACH IS TO MONITOR THE SITUATION FOR THE POSSIBILITY OF
SHOWERS DEVELOPING THEN UPDATE AS NECESSARY.
THE AIR MASS WILL CONTINUE TO MOISTEN THROUGH THE WEEKEND AND
COOL AS A MONSOONAL FLOW PATTERN MATURES OVER THE AREA. THE
CHANCES FOR SHOWERS AND THUNDERSTORMS WILL INCREASE SLIGHTLY FOR
SATURDAY AS MOISTURE INCREASES OVER THE AREA. THE HEAT WAVE WILL
SEE SOME REPRIEVE BUT IT WILL REMAIN QUITE WARM UNTIL SOUTHWEST
FLOW ALOFT ESTABLISHES OVER THE AREA EARLY NEXT WEEK.
.LONG TERM (MONDAY-THURSDAY)...
SOUTHWEST FLOW ALOFT SHOULD ESTABLISH OVER THE AREA BETWEEN SUNDAY
AND MONDAY AND BRING A COOLER AND DRIER AIR MASS TO THE AREA.
ONSHORE FLOW SHOULD INCREASE AND ALLOW FOR A STRONGER SEA BREEZE
EACH DAY...WITH A COOLING TREND PERSISTING INTO THURSDAY. SOME
LOWER VALLEY INTRUSION OF THE MARINE LAYER CLOUDS IS POSSIBLE
BETWEEN MONDAY NIGHT AND THURSDAY.
&&
.AVIATION...10/0625Z.
VFR CONDITIONS ARE EXPECTED AT ALL INLAND TERMINALS. AT COASTAL
TEMRINALS SOUTH OF POINT CONCEPTION...THERE IS A CHANCE OF LIFR
CONDITIONS AT COASTAL TERMINALS BETWEEN 08Z AND 16Z. NORTH OF POINT
CONCEPTION...VLIFR TO LIFR CONDITIONS WILL PERSIST THROUGH AT LEAST
14Z...THEN GRADUALLY IMPROVE TO VFR THROUGH 17Z.
KLAX...VFR CONDITIONS ARE EXPECTED THROUGHOUT THE PERIOD. THERE IS A
20 PERCENT CHANCE OF VLIFR TO LIFR CONDITIONS BETWEEN 12Z AND 15Z.
KBUR...VFR CONDITIONS ARE EXPECTED THROUGHOUT THE PERIOD WITH NO
WIND ISSUES.
&&
.LOX WATCHES/WARNINGS/ADVISORIES...
EXCESSIVE HEAT WARNING (SEE LAXNPWLOX).
SMALL CRAFT ADVISORY (SEE LAXMWWLOX).
SPECIAL WEATHER STATEMENT (SEE LAXSPSLOX).
&&
$$
PUBLIC...HALL
AVIATION...HALL/KAPLAN
SYNOPSIS...B/HALL
WWW.WEATHER.GOV/LOSANGELES
AREA FORECAST DISCUSSION
NWS TAUNTON MA
1015 AM EDT FRI AUG 10 2012
.SYNOPSIS...
LOW PRESSURE PASSING WEST OF NEW ENGLAND BRINGS A HIGH LIKELIHOOD OF
SHOWERS/THUNDERSTORMS TODAY THROUGH SATURDAY. SOME OF THE
THUNDERSTORMS MAY CONTAIN VERY HEAVY DOWNPOURS IN THE TROPICAL AIR
MASS. A FEW THUNDERSTORMS MAY ALSO PRODUCE STRONG WIND GUSTS. DRIER
AND LESS HUMID AIR RETURNS FOR LATE THIS WEEKEND INTO EARLY NEXT
WEEK. ANOTHER LOW PRESSURE WITH ASSOCIATED WARM AND COLD FRONTS
WILL IMPACT OUR REGION DURING THE MIDDLE OF NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
10 AM UPDATE...
WATCHING THE SITUATION CLOSELY. S NEW ENGLAND ENVELOPED IN A VERY
TROPICAL AIRMASS AT THE SFC WITH DWPTS IN THE LOW 70S. LATEST
SATELLITE EXHIBITS A FEW BREAKS IN THE MID-LVL CLOUDS...BUT
BENEATH WE ARE ALREADY SEEING N-S CLOUD STREETS INDICATIVE OF AN
UNSTABLE ENVIRONMENT.
SPC MESOANALYSIS HIGHLIGHTS INCREASING INSTABILITY OF 1-2K J/KG
ACROSS THE RGN...BUT THE BETTER 0-6 KM BULK SHEAR LAGS. WHILE
LIKELY SHOWERS AND THUNDERSTORMS WILL INCREASE IN AREAL CONVERAGE
WITH THE HEATING OF THE DAY...THE BETTER THREAT FOR SEVERE WX AND
HEAVY RAINS MAY NOT BE UNTIL LATER THIS AFTN INTO EVNG SUBSEQUENT
WITH A SHRTWV DISTURBANCE AND BETTER DEEP LYR SHEAR /30-40 KTS/
ROUNDING THRU THE BROADER TROF /PRESENTLY THE SHRTWV IS LOCATED
ACROSS THE CAROLINA RGN...LIFTING NEWD AND INVIGORATING ACTIVITY
OVER THE DELMARVA PENINSULA/. MID-LVL LAPSE RATES APPEAR MARGINAL
TODAY.
ITS IMPORTANT TO NOTE THAT ANY STORMS WITHIN THE VERY MOIST AND
TROPICAL AIRMASS WILL HAVE THE POSSIBILITY OF DROPPING AN INCH OF
RAIN IN 30 MINUTES OR LESS. PWATS ADVERTISED VIA SPC MESOANALYSIS
ALREADY THIS MORNING ARE AROUND 1.75 INCHES AND ANTICIPATING AN
INCREASE TOWARDS THE LATER HALF OF THE DAY ALONG AND AHEAD OF THE
ROUNDING SHRTWV DISTURBANCE. BUT THERE IS SOME MID-LVL DRYING
CONSEQUENTIAL FROM AIR FLOW ORIGINATING FROM THE W ATLANTIC RIDGE
/SEE THE 12Z UPR AIR ANALYSIS FROM CHATHAM AND NEW YORK VERSUS
ALBANY/. SUCH DRYING MAY IMPACT PWATS. STILL DO NOT BELIEVE THE
FLOOD THREAT WILL BE LESSENED.
SO SUMMARIZING...WITH THE SEVERE WX THREAT EXPECTING GUSTY WINDS
AND PSBL LARGE HAIL WITH A FEW OF THE STORMS. AS FOR FLOODING...
ANTICIPATE HEAVY RAINS WITHIN A SHORT PD OF TIME RESULTING IN
URBAN AND SMALL STREAM IMPACTS. STORMS LIKELY TO TRAIN ACROSS RGNS
RESULTING IN ROUNDS OF HEAVY RAINS.
OTHERWISE...SHORT-RANGE MDL SOLNS ARE NOT IMPRESSIVELY HANDLING
THE MORNING SITUATION WELL...THE 0Z CANADIAN/ECMWF ARE SEEMINGLY
DOING A GOOD JOB. THE MESO-RUC AND HRRR ARE SHOWING SOME ISSUES
WITH THE MORNING ACTIVITY. ALL FCST MDLS DO TREND AN AREA OF HEAVY
RAIN PROGRESSING NEWD FROM THE MID-ATLANTIC INTO S NEW ENGLAND
COLLOCATED WITH THE MAIN SHRTWV WITH IMPINGING S/SWLY LOW-MID LVL
LLJ TO THE REAR. THE EXACT LOCALE OF HEAVIEST RAINS IS STILL UNDER
SCRUTINY...BUT IT LOOKS LIKE HEAVY RAIN AND POTENTIAL FLOODING
WILL CONTINUE OVRNGT INTO THE MORNING PD.
TEMPS WILL BE A TAD COOLER /80 TO 85F/ THAN PREVIOUS DAYS AS CLOUD
COVER WILL BE THE MAIN FACTOR. HOWEVER DEWPOINTS ARE STILL WELL INTO
THE LOW 70 ALLOWING THE ATMOSPHERE TO BE QUITE MUGGY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SATURDAY/...
FRIDAY NIGHT...
EXPECT CONVECTION TO CONTINUE PAST SUNSET AS THERE IS SOME
ELEVATED INSTABILITY ACROSS THE AREA. STORM STRUCTURE HOWEVER WILL
BE MORE OF A CLUSTER WITH POSSIBLE BOWING SEGMENTS...DEEPENING ON
THE AMOUNT OF HEATING DURING THE DAY. WINDS WILL BACK TO THE
SOUTHWEST BY THE EVENING HOURS BLOCKING THE TROPICAL FEED FOR THE
WESTERN ZONES.
MAIN FOCUS FOR THE OVERNIGHT PERIOD IS THE WARM
FRONT THAT DEVELOPS ACROSS THE MID-ATLANTIC IN WHICH WILL MOVE
ACROSS SNE OVERNIGHT. EXPECT A LLJ TO DEVELOP BEHIND THE FRONT AND
THIS COMBINED WITH SAID FRONT AND HIGH PWATS BELIEVE A GOOD
SOAKING WILL TAKE PLACE. APPEARS THAT THE EASTERN PORTION OF THE
REGION WILL SEE THE HIGHEST AMOUNTS OF QPF AS PWATS ARE NEAR 2.5
INCHES. EXPECT PRECIP WITH PERHAPS EMBEDDED THUNDER WILL
CONTINUE WELL INTO OVERNIGHT PERIOD AND MOVE IN A MORE SOUTH TO
NORTH MANNER. IF ANY STORMS DEVELOP ALONG THE FRONT THEN THE
POTENTIAL FOR HEAVY DOWNPOURS AND FLASH FLOODING SHOULD BE
EXPECTED.
SATURDAY...
UPPER LEVEL LOW OVER THE GREAT LAKES WILL CONTINUE TO DRIFT
NORTHWARD INTO QUEBEC. THIS WILL PUSH A COLD FRONT ACROSS WESTERN NEW
ENGLAND. BELIEVE SHOWERS WILL CONTINUE INTO SATURDAY BUT EXACT
PLACEMENT IS A LITTLE UNCERTAIN. BELIEVE THE WEST HALF OF THE AREA
HAS THE BEST CHANCE SINCE THEY ARE CLOSER TO THE FRONT. THE
POTENTIAL FOR STRONG OR SEVERE STORMS IS LIMITED ONCE AGAIN TO THE
AMOUNT OF DAYTIME HEATING. BELIEVE STRONG STORMS AREA LIKELY WITH
GUSTY WINDS AND HEAVY RAIN BEING THE MAIN FOCUS. STORM STRUCTURE
SHOULD BE MORE MULTI-CELLULAR IN NATURE AND SHOULD EXPECT A LEAST
SOME STRONG STORMS. HOWEVER THE POTENTIAL OF SEVERE IS NOT OUT OF
THE QUESTION AS BULK SHEAR VALUES ARE 30KTS WITH MARGINAL LAPSE
RATES.
TEMPS WILL CREEP BACK INTO THE MID TO UPPER 80S AS 850MB TEMPS ARE
BETWEEN 16-18C . MUGGY CONDITIONS ARE EXPECTED AS DEWS ARE IN THE
LOW 70S. SATURDAY ALSO LOOKS A TAD ON THE BREEZY SIDE AS SOUTHERLY
WINDS LOOK TO GUST NEAR 20 MPH ALONG THE SOUTH COAST.
&&
.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
BIG PICTURE...
SERIES OF SHORT WAVE TROFS AMPLIFY WHAT LOOKS TO BE A MEAN LONG WAVE
TROF POSITION JUST W OF NEW ENGLAND. THE AMPLITUDE AND POSITIONING
OF THESE SHORT WAVE TROFS PROVIDE A FOCUS FOR CONVECTION AS WELL AS
OPEN THE DOOR TO TROPICAL MOISTURE. HAVE LEFT OVER SHOWERS AND TSTMS
SAT EVENING AND THEN ANOTHER BOUT WITH A WARM FRONT LATE TUE AND
COLD FRONT WED AFTERNOON AND EVE. STILL ANOTHER BOUT OF CONVECTION
AND TROPICAL MOISTURE POSSIBLE AT THE END OF THE WEEK.
SAT NIGHT...LEFT OVER SHOWERS AND EMBEDDED TSTMS MAY PERSIST MUCH OF
THE EVENING IN THE EAST. POTENTIAL REMAINS FOR SOME TSTMS TO PRODUCE
VERY HEAVY DOWNPOURS IN EASTERN SECTIONS WHERE PWATS REMAIN NEAR
OR ABOVE 2 INCHES.
SUN...THINK IT WILL BE DRY. TEMPS SHOULD REBOUND TO MID 80S WITH
MOSTLY SUNNY SKIES.
SUN NIGHT THRU MON NIGHT...LOOKS TO BE DRY. MON HIGH TEMP SHOULD
AGAIN BE IN THE MID 80S FOR MOST LOCATIONS...WHILE THE LOWER
DEWPOINTS ALLOW FOR COOLER OVERNIGHT TEMPS.
TUE/TUE NIGHT...WARMER AND MORE HUMID AIR BEGINS TO RETURN LATE TUE.
RISK OF SHOWERS/TSTMS WITH WARM FRONT LATE TUE INTO TUE NIGHT.
ALTHOUGH SOME DIFFERENCES IN TIMING AND PRECISE
CONFIGURATION...ECMWF AND GFS PAINT A SIMILAR PICTURE. HAVE CHANCE
POPS FOR LATE TUE AFTERNOON INTO TUE NIGHT.
WED...DIFFERENCES IN THE MODELS BUT ALL SUGGEST THAT A FAIRLY
PRONOUNCED SHORT WAVE TROF AND SURFACE COLD FRONT WILL MOVE THROUGH
WED AFTERNOON WITH AN AIR MASS OF WEAK TO MODERATE INSTABILITY.
HAVE CHANCE POPS IN THE GRIDS.
THU...LOOKS TO BE DRY WITH TEMPERATURES NEAR OR SLIGHTLY ABOVE
NORMAL.
&&
.AVIATION /14Z FRIDAY THROUGH TUESDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT
MODERATE...30 PERCENT TO 60 PERCENT
HIGH...GREATER THAN 60 PERCENT
OVERVIEW...MODERATE CONFIDENCE. MVFR/IFR IN FOG AND STRATUS
DEVELOPMENT THROUGH THE MORNING HOURS. BECOMING MAINLY VFR MOST
LOCATIONS BETWEEN 13Z AND 15Z WITH AREAS OF MVFR/IFR CONDITIONS
IN TSRA/SHRA BECOMING MORE NUMEROUS DURING THE AFTERNOON AND
PERSISTING INTO SATURDAY.
KBOS TAF...MODERATE CONFIDENCE. IFR CIG SHOULD IMPROVE AROUND OR
SHORTLY AFT 13Z. SCT SHRA/TSRA LIKELY THIS AFTERNOON LASTING INTO
SATURDAY WITH FREQUENT PERIODS OF MVFR CIGS/VSBYS AND A FEW BRIEF
PERIODS OF IFR CIGS/VSBYS.
KBDL TAF...MODERATE CONFIDENCE. MVFR CIG IN STRATUS EXPECTED TO
IMPROVE TO VFR BETWEEN 13Z AND 14Z BUT INCREASING PERIODS OF MVFR
CIGS/VSBYS IN TSRA/SHRA LATE THIS MORNING AND AFTERNOON. SCT
TSRA/SHRA PERSTING INTO SATURDAY. CONFIDENCE ON TIMING LOW.
OUTLOOK...SATURDAY NIGHT THROUGH TUESDAY...
SAT NIGHT...LOW TO MODERATE CONFIDENCE. WIDESPREAD AREAS OF MVFR
CIGS AND VSBYS IN SHOWERS AND EMBEDDED TSTMS. RAIN SHOULD END W TO E.
SUN THROUGH TUE MORNING...HIGH CONFIDENCE OF VFR.
TUE AFTERNOON/EVENING...MODERATE TO HIGH CONFIDENCE. MOSTLY VFR
EXCEPT FOR MVFR CIGS/VSBYS IN ANY SHOWERS/TSTMS.
&&
.MARINE...
MODERATE TO HIGH CONFIDENCE. EXPECT SOUTH TO SOUTHWEST WINDS AND
SEAS TO REMAIN BELOW SCA CRITERIA FOR TODAY. SHOWERS AND
THUNDERSTORMS LIKELY ON THE WATERS THIS AFTERNOON THROUGH TONIGHT.
A WARM FRONT WILL LIFT OVER THE WATERS DURING THE OVERNIGHT HOURS
AIDING IN SEAS TO DEVELOP OVER 5 FT. HAVE ISSUED A SCA ALONG THE
SOUTHERN WATERS WHERE 5FT SEAS ARE MOST LIKELY. LOW TO MODERATE
PROBABILITY OF PATCHY...POSSIBLY DENSE...FOG DEVELOPING ON THE
SOUTHERN WATERS TONIGHT.
OUTLOOK...SATURDAY NIGHT THROUGH TUESDAY...
MODERATE TO HIGH CONFIDENCE.
SEAS OF 5 TO 6 FT LIKELY ACROSS EXPOSED SOUTH COAST WATERS THROUGH
MOST OF SUNDAY BEFORE GRADUALLY SUBSIDING SUN NIGHT. TSTMS SAT
EVENING MAY CONTAIN LOCALLY STRONG WIND GUSTS. QUIET WEATHER
EXPECTED MONDAY THROUGH AT LEAST MOST OF TUE.
&&
.HYDROLOGY...
STRONG CHANCE OF LOCALIZED STREET FLOODING TONIGHT AND SAT WITH
POSSIBILITY OF HIGHLY LOCALIZED FLASH FLOODING. AFTER COORDINATION
WITH ADJACENT OFFICES...DECIDED TO HOLD OFF ON A FLASH FLOOD WATCH
FOR NOW. SEE A RISK OF A TROPICAL FEED AIDED BY A LOW LEVEL JET
IN AT LEAST A MARGINALLY UNSTABLE AIR MASS LATE TODAY THROUGH SATURDAY.
BEST DYNAMICS REMAIN WELL W AND N OF REGION...BUT COULD ENCOUNTER
SERIOUSLY EXCESSIVE RAINFALL IN ANY MESOSCALE BANDS THAT MAY SET
UP.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...NONE.
NH...NONE.
RI...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 8 PM THIS EVENING TO 8 PM EDT
SATURDAY FOR ANZ235-237-255-256.
&&
$$
SYNOPSIS...DUNTEN/THOMPSON
NEAR TERM...SIPPRELL/DUNTEN/THOMPSON
SHORT TERM...DUNTEN
LONG TERM...THOMPSON
AVIATION...DUNTEN/THOMPSON
MARINE...DUNTEN/THOMPSON
HYDROLOGY...WFO STAFF
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
739 AM EDT FRI AUG 10 2012
.SYNOPSIS...
A SLOW MOVING COLD FRONT WILL APPROACH THE FORECAST AREA FROM THE
NORTHWEST THROUGH TONIGHT. THE FRONT WILL BECOME DIFFUSE SATURDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
MOISTURE WILL BE HIGH AHEAD OF THE SLOW MOVING COLD FRONT TODAY.
EXPECT NUMEROUS SHOWERS AND THUNDERSTORMS MAINLY ASSOCIATED WITH
THE H85 JET. THE RAP AND NAM INDICATE THE JET WILL MAINLY AFFECT
THE FORECAST AREA EARLY TODAY. HOWEVER...CONTINUED HIGH MOISTURE
AHEAD OF THE FRONT AND DIURNAL HEATING SUPPORTS ADDITIONAL SHOWERS
AND THUNDERSTORMS LATER TODAY. LEANED TOWARD THE HIGHER GUIDANCE
POPS. CLOUDINESS SHOULD LIMIT INSTABILITY. THE NAM/S FORECAST OF
WEAK INSTABILITY APPEARS REASONABLE. IF SIGNIFICANT BREAKS AND
STRONG HEATING DOES OCCUR THEN THERE WILL BE ENOUGH SHEAR FOR A
FEW SEVERE THUNDERSTORMS. THE NAM SHOWS H85 WINDS NEAR 30 KNOTS
MAINLY EARLY TODAY. BOTH THE NAM AND GFS SHOW RAINFALL AMOUNTS
LESS THAN ONE- QUARTER OF AN INCH AND THESE GENERAL VALUES MAY BE
CORRECT SINCE THE H85 JET MAXIMUM SHOULD BE NORTHEAST OF THE
FORECAST AREA WHICH SHOULD LIMIT CONVERGENCE. HOWEVER...THERE WILL
BE A THREAT OF VERY HEAVY RAIN BECAUSE OF PRECIPITABLE WATER
VALUES AROUND 2 INCHES. ALSO...EXPECT 1000-500 MB THICKNESSES NEAR
574 WHICH IS THE PREFERRED VALUE FOR HEAVY RAIN IN AUGUST. USED
THE GUIDANCE CONSENSUS FOR THE TEMPERATURE FORECAST.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY NIGHT/...
MOISTURE AND CONVERGENCE ASSOCIATED WITH THE SLOW MOVING FRONT
SUPPORTS SHOWERS AND THUNDERSTORMS TONIGHT. HOWEVER...INSTABILITY
SHOULD BE LIMITED BY PREVIOUS CONVECTION AND DIURNAL COOLING.
FORECASTED POPS OF LIKELY EARLY AND CHANCE LATE. THE NAM AND GFS
SHOW THE FRONT LINGERING NEAR THE FORECAST AREA SATURDAY AND
SATURDAY NIGHT BUT DEEPER MOISTURE APPEARS TO SHIFT A LITTLE EAST
OF THE FORECAST AREA SATURDAY. THE NAM AND GFS MOS SUPPORT CHANCE
POPS. USED THE GUIDANCE CONSENSUS FOR THE TEMPERATURE FORECAST
THROUGH THE PERIOD.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
THE GFS SHOWS RIDGING TO THE SOUTH WITH LEE-SIDE TROUGHING IN THE
FORECAST AREA DURING MUCH OF THE EXTENDED PERIOD. THE PATTERN
SUPPORTS MAINLY DIURNAL SCATTERED THUNDERSTORMS. THE GFS ENSEMBLE
MEANS SUPPORT SLIGHT CHANCE OF CHANCE POPS. EXPECT TEMPERATURES NEAR
CLIMATOLOGY WITH LOWS IN THE LOWER 70S AND HIGHS IN THE LOWERS 90S.
&&
.AVIATION /12Z FRIDAY THROUGH TUESDAY/...
LOW LEVEL JET AFFECTING THE AREA TODAY. LIFR/IFR CIGS ACROSS THE TAF
SITES WILL LIFT TO MVFR THROUGH 14Z. COULD EVEN SEE A FEW SHOWERS
EARLY THIS MORNING. EXPECT IMPROVING CONDITIONS BY 15Z-16Z.
SOUTHWEST WINDS INCREASING TO 10-15KT BY MIDDAY WITH GUSTS NEAR 20
KNOTS. WIDESPREAD SHOWERS AND THUNDERSTORMS EXPECTED AGAIN THIS
AFTERNOON INTO TONIGHT.
EXTENDED AVIATION OUTLOOK...AN UNSETTLED WEATHER WILL PERSIST
THROUGH SUNDAY. A COLD FRONT WILL MOVE SLOWLY THROUGH THE REGION
FRIDAY THROUGH SUNDAY...THEREBY HOLDING A GOOD CHANCE FOR CONVECTION.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
07
AREA FORECAST DISCUSSION
NWS DES MOINES IA
620 AM CDT FRI AUG 10 2012
.SHORT TERM /TONIGHT/...
MAIN FOCUS TODAY WILL BE ON CLOUD COVER AND TEMPERATURES FOR THE
NEAR TERM. CWA TO REMAIN BENEATH CYCLONIC FLOW ALOFT...WITH WEAK CAA
EXPECTED THROUGHOUT THE DAY. SOME LOW LEVEL MOISTURE RESULTING IN AN
AREA OF LOW STRATUS CONTINUES TO DEVELOP OFF TO THE NORTHEAST OF THE
CWA...WITH MODEL PROGGING THIS AREA OF STRATUS TO CONTINUE TO
SPREAD/ADVECT INTO THE NORTHERN/EASTERN HALF OF THE CWA THROUGH
SUNRISE. HRRR MODEL AND GOES-R WRF FORECAST BOTH HANDLING THE
DEVELOPMENT OF THIS STRATUS WELL AND HAVE TAILORED SKY GRIDS TOWARD
THE MODEL/SATELLITE PRODUCT TRENDS. EXPECT STRATUS TO LIFT/BREAK UP
TOWARD MID/LATE MORNING ACROSS THE AREA...WITH RESULTANT MID LEVEL
CU FIELD POSSIBLE. OTHERWISE MUCH DRIER TO MOVE INTO THE CWA WITH
DEWPOINTS EXPECTED TO CONTINUE TO DROP TO AROUND 50 POSSIBLY EVEN
INTO THE 40S WITH DRIER AIR MIXING DOWN AND ADVECTING INTO THE CWA
IN NORTHERLY FLOW. WITH THE CAA...EXPECT TEMPS TO BE A FEW DEGREES
COOLER THAN YESTERDAY WITH HIGHS MAINLY IN THE UPPER 70S TO AROUND
80.
.LONG TERM /TONIGHT THROUGH THURSDAY/...
CANADIAN HIGH PRESSURE MOVING INTO THE NORTHERN PLAINS EARLY THIS
MORNING WITH TEMPERATURES DIPPING INTO THE LOW TO MID 40S OVER THE
SOUTHEAST QUADRANT. THIS SYSTEM WILL SETTLE SOUTH TODAY AND BE
STRETCHED OVER MUCH OF THE CENTRAL AND NORTHERN PLAINS TONIGHT.
WHILE SOME MODIFICATION OF TEMPERATURES IS EXPECTED...SHOULD HAVE
OVERNIGHT LOWS TONIGHT TOUCHING THE MID 40S AT A FEW LOCATIONS
ACROSS THE NORTH AND INTO THE LOW TO MID 50S ELSEWHERE. THE CLOSED
UPPER LOW THAT AFFECTED THE AREA ON THURSDAY WILL BE SHIFTING SLOWLY
NORTHEAST ACROSS THE CENTRAL GREAT LAKES THROUGH MID DAY SATURDAY
BEFORE GAINING STEAM SATURDAY NIGHT AS ANOTHER CLOSED UPPER LOW
MOVES INTO CENTRAL CANADA. THIS WILL ALLOW A TRANSITION TO A MORE
PROGRESSIVE NORTHWEST FLOW THAT WILL PERSIST THROUGH MUCH OF THE
EXTENDED.
A FAIRLY SIGNIFICANT SYSTEM WILL ARRIVE OVER THE PACIFIC NW LATE
TODAY THEN MOVE ACROSS THE ROCKIES AND PRODUCE LEE SIDE CYCLOGENESIS
INTO SATURDAY. SATURDAY WILL BE ANOTHER PLEASANT DAY AND EXPECT
TEMPERATURES TO BE NEAR THE HIGH END OF GUIDANCE WITH DRY SFC AIR
HEATING UP EFFICIENTLY. MID LEVEL THETA-E ADVECTION WILL COMMENCE
SATURDAY NIGHT WITH THE INITIAL WAVE BEING SPENT ON MID LEVEL
SATURATION. GULF MOISTURE WILL BREAK FREE AND BEGIN TO STREAM
NORTHWARD SATURDAY NIGHT AS WELL WITH THE MOISTURE ADVECTION
ARRIVING LATE AIDED BY AN INCREASING LOW LEVEL JET APPROACHING 40
KTS. THE COMBINATION OF THE MULTI LEVEL KINEMATICS AND
THERMODYNAMICS WILL RESULT IN A DEEPLY FORCED SYSTEM WITH SHOWERS
AND THUNDERSTORMS ARRIVING OVER THE WEST AFTER MIDNIGHT. ADDITIONAL
CHANCES WILL CONTINUE SUNDAY AND SUNDAY NIGHT WITH AS THE SECOND
SEGMENT OF THE UPPER LEVEL SYSTEM ARRIVES ALONG WITH THE SFC LOW
REFLECTION. GENERAL AGREEMENT DEVELOPING THAT THE SFC LOW WILL SHIFT
EAST ACROSS SOUTHERN IA AND WOULD ALLOW A PORTION OF THE WARM SECTOR
TO LIFT INTO THE STATE. HIGH VARIABILITY POSSIBLE WITH HIGH
TEMPERATURES ON SUNDAY WHERE HIGHS COULD STRUGGLE IN THE 60S UNDER
INCREASING CLOUDS AND MORE PROLONGED PRECIPITATION WHILE RISING WELL
INTO THE 80S SOUTH WHERE SOME SUN COULD BE POSSIBLE. THIS COULD LEAD
TO AN AREA OF SFC BASED THUNDERSTORMS AND AN AREA WITH SEVERE
POTENTIAL. PRECIPITATION CHANCES CONTINUE OVER MAINLY THE EAST
SUNDAY EVENING BEFORE ENDING.
THE REMAINDER OF THE EXTENDED IS HIGHLIGHTED BY SEVERAL IMPULSES
RIPPLING THROUGH THE NW FLOW WHILE A DEEP UPPER LEVEL LOW DROPS INTO
ALBERTA AND MANITOBA BY MID WEEK. OVERALL TIMING BECOMES DIFFICULT
UNDER THESE SITUATIONS BUT GENERAL CONSENSUS IS A WEAK WAVE ARRIVING
TUE NIGHT INTO WED WITH A MORE SIGNIFICANT SYSTEM IMPACTING THE AREA
TOWARD THE END OF THE PERIOD AS ENERGY ASSOCIATED THE SOUTHERN
CANADA SYSTEM ARRIVES.
&&
.AVIATION...10/12Z
SOME LOW STRATUS IMPACTING NORTHERN TAF SITES INITIALLY SHOULD LIFT
INTO A SCT-BKN VFR CU DECK BY LATE MORNING. NORTHERLY TO
NORTHEASTERLY WINDS EXPECTED THROUGH THE PERIOD...MAY HAVE SOME
GUSTS BY LATE MORNING INTO THE AFTERNOON HOURS. MAINLY VFR
CONDITIONS EXPECTED BEYOND 15Z AT ALL TAF SITES.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM...BEERENDS
LONG TERM...DONAVON
AVIATION...BEERENDS
AREA FORECAST DISCUSSION
NWS RALEIGH NC
1030 AM EDT FRI AUG 10 2012
.SYNOPSIS...
A STRONG COLD FRONT WILL APPROACH OUR REGION FROM THE WEST TODAY AND
TONIGHT...THEN CROSS CENTRAL NORTH CAROLINA SATURDAY AND SATURDAY
NIGHT.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1030 AM FRIDAY...
SKIES ARE OVERCAST WITH WIDESPREAD STRATUS THIS MORNING..BETWEEN AN
UPPER DISTURBANCE AND ASSOCIATED PRECIP DEPARTING TO THE
NORTHEAST...AND TWO MORE APPROACHING FROM BOTH THE NORTHWEST AND
SOUTHWEST LATER TODAY. A FEW LIGHT SHOWERS ARE MOVING THROUGH THE
PIEDMONT THIS MORNING...BUT OVERALL THERE IS A LULL ACROSS THE
CAROLINAS BETWEEN THE AFOREMENTIONED UPPER FEATURES. AN UPPER
LOW/SURFACE CYCLONE HAVE NOW DEVELOPED OVER THE GREAT LAKES AND THE
ASSOCIATED COLD FRONT EXTENDS SOUTH THROUGH OH/KY/TN....WITH A
STREAM OF 2 INCH PWS ACROSS THE NC/SC PIEDMONT AND COASTAL PLAIN. A
LINE OF PREFRONTAL CONVECTION IS CURRENTLY MOVING THROUGH EASTERN TN
AND WV...BUT THE DEEP LAYER FLOW IS FORECAST TO BECOME MORE
SOUTHWESTERLY AS THE UPPER TROUGH CONTINUES TO DEEPEN... AND THE
PROGRESSION OF CONVECTIVE LINE SHOULD SLOW AS IT CROSSES THE
MOUNTAINS THIS MORNING. IN FACT... HRRR FORECASTS SHOW A LINE OF
CONVECTION MOVING INTO THE WESTERN PIEDMONT CLOSER TO 00Z.
MEANWHILE...THE AFOREMENTIONED DISTURBANCE NEAR THE GULF COAST
SHOULD BE DRAWN NORTH-NORTHEASTWARD...APPROACHING THE SOUTHERN CWA
BY 00Z. WHILE A FEW SHOWERS AND STORMS WILL BE POSSIBLE THROUGH MID
AFTERNOON WITH WEAK DISTURBANCES IN THE MOIST SOUTHWESTERLY FLOW
ALOFT...WE SHOULD BE ABLE TO PUSH MORE SIGNIFICANT POPS BACK UNTIL
AFTER 21-22Z.
CONCERNING THE SEVERE THREAT THROUGH THIS EVENING...IT APPEARS THE
WIDESPREAD STRATUS MAY LINGER THROUGH MIDDAY...WITH MORNING PIREPS
CONTINUING TO REPORT 3K FT DEPTH TO THE STRATUS. VISIBLE IMAGERY
SHOWS MORE PROMINENT BREAKS IN THE CLOUDS OVER WESTERN NC AND OVER
THE COASTAL PLAIN. THUS...TWO INSTABILITY AXES MAY DEVELOP IN THESE
REGIONS...AND MODELS SUGGEST 1500 J/KG OR MORE OF MLCAPE
POSSIBLE..WITH VALUES AROUND 1000 J/KG OVER THE PIEDMONT. STRONGER
DEEP LAYER SHEAR WILL BE LOCATED WEST OF THE MOUNTAINS FOR MOST OF
THE DAY...ALTHOUGH THE MID LEVEL HEIGHT GRADIENT WILL BEGIN TO
STRENGTHEN THIS EVENING...AND THE RAP SHOWS 25-35KT OF 0-6KM BULK
SHEAR DEVELOPING OVER THE WESTERN PIEDMONT. TO THE EAST...WHERE DEEP
LAYER FLOW IS A BIT WEAKER...MORE LIKE 20-25KT OF DEEP BULK
SHEAR...MORNING RAOBS SUGGEST A BELT OF 30KT 925-850MB FLOW EXISTS
AND THE SPC MESOANALYSIS CURRENTLY SHOWS AN AXIS OF 20KT 0-1KM SHEAR
OVER THE COASTAL PLAIN. SO WHILE DEEP SHEAR MAY NOT SUPPORT
SUPERCELLULAR ACTIVITY... IT IS POSSIBLE THAT A FEW CLUSTERS OF
STORMS OR EVEN DISCRETE CELLS WITH WEAK ROTATION COULD DEVELOP THIS
EVENING. THIS IS ALL SIGNIFICANTLY DEPENDENT ON OUR DIURNAL
DESTABILIZATION AND WHETHER OR NOT CONVECTION CAN HOLD TOGETHER
SINCE THE MAIN FORCING MECHANISMS WILL NOT ARRIVE UNTIL CLOSER TO
00Z.
OTHERWISE...HAVE MADE SOME MINOR ADJUSTMENTS TO AFTERNOON
HIGHS...WITH SLIGHTLY HIGHER VALUES OVER THE EASTERN AND WESTERN
AREAS...BUT GENERALLY 84-87 SHOULD STILL BE ATTAINABLE IF BREAKS IN
CLOUDS DEVELOP BY MID AFTERNOON. -SMITH
TONIGHT...SW FLOW WILL DEEPEN OVER CENTRAL NC IN RESPONSE TO
AMPLIFYING TROUGH OVER THE EASTERN LAKES-OH VALLEY. THIS SUGGEST A
THREAT FOR SHOWERS-STORMS TO TRAIN REPEATEDLY ACROSS THE SAME
LOCATIONS. SINCE FLOW WILL BE TAPPING AN AIR MASS WITH A VERY HIGH
MOISTURE CONTENT OVER THE NORTHERN GULF...COULD SEE A MODERATE
FLASH FLOOD THREAT DEVELOP OVER CENTRAL NC OVERNIGHT. MODEL GUIDANCE
DEPICT BEST LIFT ALOFT IN ASSOCIATION WITH THE UPPER JET WHILE LIFT
BELOW 700MB WEAK AT BEST. THUS PLAN TO HAVE POPS NO HIGHER THAN
70-80 PERCENT OVER THE WEST HALF OVERNIGHT...TRENDING TO NEAR 60
PERCENT SE (WHICH MAY BE GENEROUS).
TEMPS TODAY DEPENDENT ON THE AMOUNT OF SUN THAT OCCURS. EXPECT
CONDITIONS TODAY SIMILAR TO THE PAST FEW DAYS WHERE MAX TEMPS IN THE
MID 80S COMMON. MIN TEMPS TONIGHT UPPER 60S TO LOWER 70S.
&&
.SHORT TERM /SATURDAY AND SATURDAY NIGHT/...
AS OF 315 AM FRIDAY...
SATURDAY...EXPECT SCATTERED CONVECTION TO BE ONGOING ACROSS CENTRAL
NC SATURDAY MORNING. AS AIR MASS BECOMES MARGINALLY UNSTABLE IN THE
AFTERNOON AND SURFACE COLD FRONT ENTERS THE MOUNTAINS...SHOULD SEE
AN UPTICK IN CONVECTIVE COVERAGE IN THE AFTERNOON. BULK SHEAR VALUES
30-35KTS ACROSS THE ENTIRE FORECAST AREA SUGGEST DECENT POTENTIAL
FOR ORGANIZED STORMS IN THE FORM OF BROKEN LINE SEGMENTS THOUGH
INSTABILITY MAY BE LACKING FOR SEVERE STORMS DUE TO LIMITED
INSOLATION CAUSED BY CONSIDERABLE CLOUDINESS AND SCATTERED SHOWERS.
IF PARTIAL SUN OCCURS IN THE LATE MORNING INTO THE
AFTERNOON...PROBABILITY FOR SEVERE STORMS WILL INCREASE
EXPONENTIALLY. AGAIN...DUE TO TAP OF TROPICAL MOISTURE AND DEEP SW
FLOW...COULD SEE SHOWERS-STORMS TRAIN NEWD ACROSS THE
REGION...LEADING TO POSSIBLE FLASH FLOODING EPISODE.
MAX TEMPS MAINLY IN THE MID 80S THOUGH IF SHOWERS MORE
WIDESPREAD...COULD SEE MAX TEMPS 3-5 DEGREES COOLER...ESPECIALLY
WEST HALF.
WITH PASSAGE OF LOW-MID TROUGH SATURDAY EVENING IN THE WEST...EXPECT
CHANCES FOR CONVECTION TO BEGIN TO DECREASE IN THIS REGION.
MEANWHILE DECENT CHANCES FOR SCATTERED SHOWERS-STORMS SHOULD PERSIST
THROUGH MIDNIGHT IN THE EAST. MIN TEMPS MID 60S NW TO NEAR 70-LOWER
70S SE.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
AS OF 245 AM FRIDAY...
MID/UPPER LOW EXPECTED TO BE CENTERED INVOF THE NORTHERN GREAT LAKES
REGION AND NEAR THE ONTARIO/QUEBEC BORDER 12Z SUNDAY IS EXPECTED TO
CONTINUING LIFTING NNE ON SUNDAY. THIS WILL RESULT IN FLOW ALOFT
ACROSS CENTRAL NC BECOMING MORE WESTERLY WITH DRIER AIR ALOFT
CONTINUING TO FILTER INTO THE AREA. AT THE SURFACE THE WEAK FRONT IS
EXPECTED TO WASHOUT/DISSIPATE ACROSS THE AREA ON SUNDAY INTO MONDAY.
GIVEN THIS ALONG WITH THE DEPARTURE OF THE FORCING ALOFT AND MOIST
AIR ALOFT... EXPECTED GENERALLY DRY CONDITIONS ON SUNDAY INTO MONDAY
(OUTSIDE OF POSSIBLE A FEW LINGERING SHOWERS/STORMS ACROSS THE FAR
EAST ON SUNDAY... SLIGHT CHANCE AT BEST THOUGH). CHANCE FOR POPS ARE
EXPECTED TO INCREASE BY TUESDAY INTO TUESDAY NIGHT/PERHAPS LINGERING
INTO WEDNESDAY/THURSDAY AS A LOW AMPLITUDE S/W TROUGH AND ASSOCIATED
WEAK COLD FRONT/SURFACE TROUGH MOVE ACROSS THE AREA. GIVEN TIMING
AND SOME STRENGTH DIFFERENCES WILL CONTINUE TO ONLY GO WITH A LOW
END CHANCE POPS FOR TUESDAY/TUESDAY EVENING... WITH DIURNAL SLIGHT
CHANCE POPS FOR WEDNESDAY INTO THURSDAY WITH THE REMNANT LINGERING
SURFACE TROUGH. HIGH TEMPS DURING THE PERIOD ARE EXPECTED TO
GENERALLY BE IN THE UPPER 80S TO LOWER 90S... WITH LOWS GENERALLY
RANGING FROM THE UPPER 60S TO LOWER 70S (WITH MAYBE SOME LOW TEMPS
IN THE LOWER TO MID 60S IN THE RURAL LOCATIONS AND NORTHWEST
PIEDMONT ON MONDAY MORNING).
&&
.AVIATION /12Z FRIDAY THROUGH TUESDAY/...
AS OF 707 AM FRIDAY...
LOW CLOUDS HAVE DEVELOP OVER MOST OF CENTRAL NC EARLY THIS MORNING
IN WAKE OF THE SHOWERS AND SCATTERED T-STORMS THAT CROSSED THE
WESTERN COUNTIES OVERNIGHT. CEILINGS IN THE IFR/LOW END MVFR RANGE.
CEILINGS SHOULD GRADUALLY LIFT TOT HE HIGH END MVFR/LOW END VFR BY
LATE MORNING. ANY FOG ACROSS THE REGION SHOULD BE SPOTTY AND
DIMINISH BY MID MORNING (IF NOT SOONER).
WHILE ISOLATED SHOWERS POSSIBLE THROUGH EARLY AFTERNOON...EXPECT
CONVECTION TO GROW IN COVERAGE AND INTENSITY BY MID
AFTERNOON...PARTICULARLY IN THE VICINITY OF KFAY AND KRWI WHERE
INITIAL MID LEVEL TROUGH WILL RESIDE. IN THE NW PIEDMONT INCLUDING
THE TRIAD TERMINALS...BETTER CONVECTIVE PROBABILITIES MAY HOLD OFF
UNTIL EVENING AS A MID LEVEL TROUGH APPROACHES FROM THE NW. THIS
FEATURE MAY SUSTAIN SCATTERED CONVECTION IN VICINITY OF KINT AND
KGSO WELL INTO THE NIGHT.
EXPECT EPISODES OF SCATTERED SHOWERS AND T-STORMS ACROSS CENTRAL NC
SATURDAY INTO SATURDAY EVENING WITH ASSOCIATED MVFR CONDITIONS. AT
THIS TIME...IT APPEARS THE HEAVIER SHOWERS AND STORMS WILL OCCUR
SATURDAY AFTERNOON ALONG AND EAST OF HIGHWAY 1.
DRIER MORE STABLE AIR WILL GRADUALLY OVERSPREAD CENTRAL NC LATE
SATURDAY NIGHT INTO SUNDAY LEADING TO IMPROVING AVIATION CONDITIONS.
MAINLY VFR CONDITIONS EXPECTED MONDAY INTO TUESDAY.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...WSS
NEAR TERM...WSS
SHORT TERM...WSS
LONG TERM...BSD
AVIATION...WSS
AREA FORECAST DISCUSSION
NWS BISMARCK ND
927 AM CDT FRI AUG 10 2012
.DISCUSSION...LATEST VISIBLE SATELLITE IMAGERY ALONG WITH REGIONAL
RADAR SHOWS A COUPLE SHORTWAVES APPROACHING/PROPAGATING THROUGH
WESTERN NORTH DAKOTA. THE FIRST WAS SEEN NEAR WATFORD CITY WITH AN
ISOLATED SHOWER IN FAR EASTERN DUNN COUNTY...WHICH HAS WEAKENED
AND DISSIPATED. A MORE SUBSTANTIAL AREA OF SHOWERS AND ISOLATED
THUNDERSTORMS WAS NOTED FROM GLASGOW SOUTH TO BILLINGS ASSOCIATED
WITH A SECOND SHORTWAVE. LATEST RADAR TRENDS SHOW SOME WEAKENING
AND THE LATEST HRRR MODEL HAS THIS AREA REACHING THE WESTERN
BORDER BY AROUND 18Z AND THEN INTO OUR SOUTHWEST ZONES THIS
AFTERNOON...BUT IN A MUCH WEAKER STATE THAN CURRENT. THIS WILL BRING
QUITE A BIT OF CLOUDINESS TO THE WEST LATER THIS MORNING AND HAVE
INCREASED CLOUD COVERAGE TO ACCOUNT FOR THIS. MAY HAVE TO LOWER
HIGH TEMPERATURES IN WEST IF CLOUDS REMAIN MOST OF THE AFTERNOON.
REST OF FORECAST REMAINS ON TRACK WITH SATURDAY BECOMING INCREASING
WET ACROSS WESTERN AND CENTRAL NORTH DAKOTA WITH UPWARDS OF
NEAR/AROUND AN INCH POSSIBLE IN MANY LOCALES.
&&
.AVIATION...SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS IN
EASTERN MONTANA CONTINUE TO MOVE TOWARD THE WESTERN NORTH DAKOTA
BORDER. INDICATIONS ARE THIS AREA WILL WEAKEN INTO A SCATTERED
SHOWER REGIME THROUGH THE MORNING...HOWEVER WILL MONITOR THE
TRENDS AND MAY HAVE TO ADD A VCSH/VCTS IN KISN AND/OR KDIK IF THE
AREA HOLDS TOGETHER. OTHERWISE SHOWERS AND STORMS ARE EXPECTED TO
INCREASE IN COVERAGE AFTER 00Z TONIGHT...WITH MAIN IMPACTS AT
KISN/KDIK THROUGH 12Z SATURDAY.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
DISCUSSION...KS
AVIATION...RK
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
1201 PM EDT FRI AUG 10 2012
.SYNOPSIS...
A STRONG UPPER LEVEL TROUGH WILL CROSS OVER THE GREAT LAKES
TODAY...AND PUSH A COLD FRONT ACROSS THE MID ATLANTIC. THIS FRONT
WILL TRIGGER NUMEROUS SHOWERS AND THUNDERSTORMS THIS AFTERNOON AND
EVENING...WITH A FEW STORMS POSSIBLY BECOMING STRONG TO SEVERE.
ONCE THE COLD FRONT DEPARTS LATER TONIGHT INTO SATURDAY...HIGH
PRESSURE WILL ARRIVE TO PROVIDE COOLER AND DRIER CONDITIONS FOR
THE REST OF THIS WEEKEND INTO EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1200 PM EDT FRIDAY...
THE SHOWERS OVER WEST VIRGINIA ARE STILL PRESENT BUT GRADUALLY
DECAYING. NEW DEVELOPMENT OF SHOWERS AND THUNDERSTORMS HAS BEEN
DELAYED A FEW HOURS TOWARD THE MID AFTERNOON AND EVENING...AS
INSTABILITY IS CURRENTLY STILL LACKING. THE THREAT FOR SEVERE
WEATHER TODAY CONTINUES TO DIMINISH DUE TO CLOUD COVER REMAINING
QUITE THICK OVER THE AREA...BUT SOME SUNSHINE IS PEEKING THROUGH
ALONG THE BLUE RIDGE. MINOR TWEAKS WERE MADE TO THE POPS AND
TEMPERATURES TO ACCOUNT FOR THE RECENT TRENDS ON RADAR AND
SATELLITE. ALSO...WINDS WERE BUMPED UPWARD DUE TO ROANOKE AND
DANVILLE BOTH OBSERVING A GUSTY SOUTHWEST WIND DEVELOPING...WHICH
SHOULD CONTINUE THROUGH THE AFTERNOON.
AS OF 1015 AM EDT FRIDAY...
DUE TO THE DEPARTING BAND OF SHOWERS AND THUNDERSTORMS FROM LAST
NIGHT...AND ANOTHER SMALL BAND OF SHOWERS CROSSING OVER SOUTHEAST
WEST VIRGINIA AT THIS MOMENT...THERE WILL BE LOTS OF CLOUD COVER
TO ERODE OVER THE AREA FOR ANY SIGNIFICANT RISK OF SEVERE WEATHER.
THE SMALL BAND OF SHOWERS OVER WEST VIRGINIA WILL GRADUALLY
DISSIPATE AS IT CROSSES THE BLUE RIDGE IN A FEW HOURS. RECOVERING
THE INSTABILITY WILL BE THE KEY FOR TODAY. LAPSE RATES IN THE 12Z
RNK SOUNDING ARE NOT IMPRESSIVE...BUT WITH ENOUGH DAYTIME HEATING
AND DYNAMICAL SUPPORT AS THE SURFACE COLD FRONT DRAWS
CLOSER...THERE SHOULD BE SUFFICIENT SUPPORT FOR THE GROWTH OF
NUMEROUS SHOWERS AND THUNDERSTORMS LATER THIS AFTERNOON. IF ANY OF
THESE STORMS BECOME STRONG TO SEVERE...DAMAGING WINDS AND HEAVY
RAIN WILL BE THE PRIMARY THREATS.
SINCE CLOUD COVER AND BANDS OF CONVECTION WILL BE ONGOING
THROUGHOUT THE DAY...THE TEMPERATURE FORECAST IS QUITE
PROBLEMATIC. AT THIS TIME...TEMPERATURES WERE BUMPED UPWARD FOR
HIGHS WEST OF THE BLUE RIDGE DUE TO SOME BREAKS IN THE CLOUDS.
OTHER AREAS WERE KEPT CLOSE TO THE PREVIOUS FORECAST AND MOS
GUIDANCE...WITH HIGHS IN THE MID TO UPPER 70S WEST OF THE BLUE
RIDGE...AND LOWER TO MID 80S IN THE PIEDMONT. WITH REGARDS TO
POPS...A SMALL AREA OF LIKELY CHANCES WERE UTILIZED TO ACCOUNT FOR
THE DECAYING BAND OF SHOWERS OVER WEST VIRGINIA THIS MORNING.
LIKELY POPS WEST OF THE BLUE RIDGE...AND CATEGORICAL POPS OVER THE
PIEDMONT WERE PLACED THIS AFTERNOON AND EVENING...AS THERE
SHOULD BE BANDED CONVECTION FORMING ALONG AND WEST OF THE BLUE
RIDGE...AND BECOMING MORE ORGANIZED AS IT HEADS EASTWARD.
AS OF 315 AM EDT FRIDAY...
MAIN CONCERN TODAY WITH THE DEGREE OF POSSIBLE RENEWED CONVECTION
LATER ON AS THE UPPER LOW TO THE NW PROPELS A STRONG COLD FRONT TO
ALONG THE WESTERN SLOPES THIS EVENING AND EAST OF THE BLUE RIDGE
OVERNIGHT. AGAIN ONE OF THE MAIN FACTORS IS WITH JUST HOW MUCH
DEEP INSTABILITY CAN BE GENERATED THIS AFTERNOON IN THE WAKE OF
THE CURRENT MVC THAT WILL EXIT THE CWA BY DAYBREAK. THIS FEATURE
AND ITS CONVECTION HAVE BASICALLY REMOVED ANY LINGERING CAPE FROM
THU EVENING AND WILL NEED A PERIOD OF STRONG HEATING TO REGENERATE
ENOUGH INSTABILITY FOR A MORE WIDESPREAD SEVERE THREAT. LATEST
FCST SOUNDINGS DO SHOW WIND FIELDS STRENGTHENING/BACKING ALOFT
AHEAD OF THE UPSTREAM TROF THRU THIS EVENING SUGGESTING POTENTIAL
FOR BANDS OF DEEPER CONVECTION THAT MAY EVENTUALLY LINE UP ESPCLY
OUT EAST BY THIS EVENING. HOWEVER LATEST MODELS REMAIN SPREAD
ACROSS THE BOARD WITH TIMING AND LOCATION ISSUES OF PRE- FRONTAL
LIFT PER SLOWNESS IN INITIALIZING WITH THE CURRENT REMNANT MCS
ATTM. APPEARS BEST SOLUTION IS TO LEAN TOWARD THE LATEST HRRR AND
GO WITH DEVELOPMENT OF MULTICELLULAR BANDS OVER THE MOUNTAINS BY
EARLY AFTERNOON PER UNIDIRECTIONAL FLOW AND THETA-E RIDGING...WITH
THIS COVERAGE OR ANOTHER LINE GRADUALLY ORGANIZING UPON HEADING
EAST INTO BETTER INSTABILITY OUT EAST THRU EARLY EVENING. THIS
AGAIN BASED ON AT LEAST SOME HEATING AS SUGGESTED BY THE LATEST
NAM WHICH BREAKS OPEN THE MID DECK LATER THIS MORNING AHEAD OF THE
BOUNDARY. THUS HAVE ADJUSTED POPS TO REFLECT A BREAK IN COVERAGE
PER WEAK SUBSIDENCE IN BEHIND THE PASSING VORT EARLY THIS
MORNING...INCREASING TO LIKELY/CAT POPS WEST EARLY/MID
AFTERNOON...THEN TRANSLATING EAST INTO EARLY THIS EVENING. THINK
COVERAGE MOVING ENOUGH TO PRECLUDE A FLASH FLOOD WATCH BUT
CERTAINLY A WIND THREAT GIVEN DECENT FCST DCAPES WHICH WILL COVER
IN THE HWO PER SWODY1 SLIGHT RISK. WILL STAY ON THE WARM SIDE OF
MOS TEMPS TODAY AS THINKING SOME INSOLATION BUT IF CLOUDS HOLD AND
CONVECTION FASTER THEN HIGH BUST POTENTIAL REMAINS.
EXPECT MAIN AXIS OF CONVECTION TO BE EAST OF THE MOUNTAINS THIS
EVENING AND MAY TAKE SOME TIME TO EXIT THE PIEDMONT AS ANOTHER WEAK
IMPULSE RIDES UP THE FRONT. THINK SEVERE POTENTIAL LIMITED BEHIND
THE INIT WAVE OF STORMS BUT LINGERING HEAVY RAIN THREAT COULD
PERSIST WHILE SHOWERS BECOME WIDELY SCATTERED OR END BEHIND THE
BOUNDARY OVER THE MOUNTAINS OVERNIGHT. THEREFORE DID DECREASE POPS
A BIT FASTER WEST THINKING CONVECTION WILL HELP TAKE DEEP MOISTURE
TO THE EAST LATE...BUT LIKELY STILL LOTS OF CLOUDS AS THE UPPER
FLOW REMAINS SW AND PARALLEL TO THE SFC FRONT. MAIN PUSH OF 85H
COOL ADVECTION WILL STILL BE WEST OF THE BLUE RIDGE LATE TONIGHT
SO KEEPING TEMPS WARMER OUT EAST AND NOT QUITE AS COOL MOUNTAINS
PER CLOUD COVER. OTRW RANGE OF LOWS FROM AROUND 60 FAR WEST TO
65-70 SE LOOKS BEST.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 300 AM EDT FRIDAY...
SHORTWAVE PIVOTS ACROSS THE CENTRAL APPALACHIANS SATURDAY AFTERNOON.
THIS WILL KEEP THE THREAT OF SHOWERS AND ISOLATED THUNDERSTORMS
GOING IN THE EAST WITH COOL POOL ALOFT. 8H TEMPS COOL TO +14C...SO
WITH SOME CLOUD COVER FROM THE COLDER AIR ALOFT...EXPECT HIGHS
CLOSE TO THE ADJMETBC WITH READINGS FROM THE MID 70S IN THE
MOUNTAINS TO THE MID 80S IN THE SOUTHEAST.
DRIER AIR WILL FINALLY WORKS IN FROM THE NORTHWEST SATURDAY NIGHT
INTO SUNDAY WITH DEWPOINTS DROPPING INTO THE UPPER 40S/LOWER 50S IN
THE HIGHER ELEVATIONS WITH MID 50S VALLEYS. THE PIEDMONT COULD SEE
SOME 50S DEWPOINTS BUT HARD TO DISPLACE THE HUMID AIRMASS ACROSS THE
CAROLINAS AS THE FLOW ALOFT STAYS WSW. PLAYED LOW TEMPERATURES
SATURDAY NIGHT FROM THE LOWER 50S IN THE MOUNTAINS TO THE LOWER 60S
IN THE EAST.
ON SUNDAY...TEMPERATURES MODERATE WITH WSW FLOW AND MORE SUNSHINE.
HEIGHTS/8H TEMPERATURES INCREASE AGAIN...HIGHS SUNDAY RETURNING TO
AROUND 80 DEGREES IN THE MOUNTAINS TO THE UPPER 80S IN THE
SOUTHEAST. LEANED TOWARDS THE ECMWFBC FOR SUNDAY NIGHT LOW
TEMPERATURES WITH VALUES FROM THE MID 50S IN THE WEST TO THE MID 60S
IN THE EAST.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
AS OF 400 PM EDT THURSDAY...
DRIER AIRMASS WILL BE DISPLACED DURING THIS PERIOD AS THE FRONT FROM
THE SHORT TERM PERIOD STALLS ACROSS THE CAROLINAS/TN VALLEY THEN
SHIFTS SLOWLY NORTH BY TUESDAY AS ANOTHER WAVE OF LOW PRESSURE
SHIFTS ACROSS IT FROM THE LOWER MISSOURI VALLEY INTO THE VA
TIDEWATER FROM MON-TUE. THIS FRONT WILL BE CLOSE ENOUGH THAT
SHOWER/TSRA CHANCES INCREASE AGAIN BY TUESDAY. ONCE THE
SHORTWAVE/ASSOCIATED SFC LOW PASS TUESDAY AFTERNOON...WEAK HIGH
PRESSURE WILL PUSH THE FRONT BACK SOUTH INTO THE GA/SC BY WEDNESDAY
AND THE AIRMASS DRIES OUT SOME...BUT THE UPPER TROUGH IS NOT AS DEEP
AS THIS WEEKENDS. OVERALL...THE TEMPS NEXT WEEK WILL AVERAGE
80S/LOWER 90S FOR HIGHS AND 60S FOR LOWS.
&&
.AVIATION /16Z FRIDAY THROUGH TUESDAY/...
AS OF 650 AM EDT FRIDAY...
INITIAL AREA OF LEFTOVER SHOWERS FROM EARLIER MCS SLOWLY FADING
ACROSS THE EAST AND SHOULD ONLY AFFECT KLYH DURING THE NEXT HOUR
OR TWO. OTRW LOOKING AT MAINLY MVFR CIGS THRU MID MORNING WITH
PERIODS OF IFR INCLUDING PATCHY FOG ESPCLY VALLEYS AND AROUND
KDAN/KLYH. NEXT BAND OF DEVELOPING CONVECTION NOW WEST OF THE
MOUNTAINS LOOKS TO ARRIVE ACROSS SE WVA AROUND MID MORNING BEFORE
WEAKENING. THUS WILL INCLUDE A VCSH AT KBLF/KLWB AND SHOW CIGS
LIFTING INTO VFR LEVELS ELSW BY LATE MORNING OR MIDDAY AS SW FLOW
STARTS TO MIX THINGS OUT. JUST HOW FAR EAST THIS BROKEN BAND OF
SHRA/TSRA MAKES IT IFFY GIVEN RATHER STABLE CONDITIONS SO WILL
HOLD OFF PUSHING COVERAGE EASTWARD FOR NOW.
HOWEVER EXPECT TO SEE MORE SHOWERS AND THUNDERSTORMS TAKE SHAPE
AHEAD OF THE UPSTREAM COLD FRONT LATE THIS MORNING INTO THE
AFTERNOON AS A DEEP UPPER LEVEL TROUGH APPROACHES THE AREA. WILL
BE LOOKING AT A FEW STRONG STORMS TO START THE AFTERNOON...AND
EXPECT THAT THESE STORMS WILL FORM INTO A LINE OR TWO JUST AHEAD
OF THE COLD FRONT AS IT ENTERS THE PIEDMONT REGION DURING EARLY
EVENING. THESE STORMS WILL BE CAPABLE OF PRODUCING STRONG WINDS
ALONG WITH PERIODIC MVFR/IFR THIS AFTERNOON. THEREFORE GIVEN
EXPECTED COVERAGE WILL INCLUDE CONVECTIVE MENTION AS PREVAILING
FROM WEST TO EAST STARTING THIS AFTERNOON. THUNDERSTORM ACTIVITY
IS EXPECTED TO END ACROSS THE AREA AS THE FRONT EXITS TO THE EAST
DURING LATE EVENING...AT WHICH POINT DRIER AIR ASSOCIATED WITH
HIGH PRESSURE WILL RESULT IN VFR CONDITIONS HEADING INTO THE EARLY
PART OF NEXT WEEK.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...PW
NEAR TERM...JH/PW
SHORT TERM...KK
LONG TERM...WP
AVIATION...JH/KM/NF
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
703 AM EDT FRI AUG 10 2012
.SYNOPSIS...
A STRONG UPPER LEVEL TROUGH WILL PASS INTO THE GREAT LAKES
TODAY...DRAGGING A COLD FRONT ACROSS THE REGION THIS EVENING.
THIS WILL RESULT IN ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS
THIS AFTERNOON AND EVENING...WITH A FEW STORMS BECOMING STRONG TO
SEVERE. ONCE THE COLD FRONT MOVES EAST OF THE AREA LATE
TONIGHT...HIGH PRESSURE WILL BUILD IN...BRINGING COOLER AND DRIER
AIR IN FOR THE REMAINDER OF THE WEEKEND AND THE EARLY PART OF NEXT
WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 315 AM EDT FRIDAY...
MAIN CONCERN TODAY WITH THE DEGREE OF POSSIBLE RENEWED CONVECTION
LATER ON AS THE UPPER LOW TO THE NW PROPELS A STRONG COLD FRONT TO
ALONG THE WESTERN SLOPES THIS EVENING AND EAST OF THE BLUE RIDGE
OVERNIGHT. AGAIN ONE OF THE MAIN FACTORS IS WITH JUST HOW MUCH
DEEP INSTABILITY CAN BE GENERATED THIS AFTERNOON IN THE WAKE OF
THE CURRENT MVC THAT WILL EXIT THE CWA BY DAYBREAK. THIS FEATURE
AND ITS CONVECTION HAVE BASICALLY REMOVED ANY LINGERING CAPE FROM
THU EVENING AND WILL NEED A PERIOD OF STRONG HEATING TO REGENERATE
ENOUGH INSTABILITY FOR A MORE WIDESPREAD SEVERE THREAT. LATEST
FCST SOUNDINGS DO SHOW WIND FIELDS STRENGTHENING/BACKING ALOFT
AHEAD OF THE UPSTREAM TROF THRU THIS EVENING SUGGESTING POTENTIAL
FOR BANDS OF DEEPER CONVECTION THAT MAY EVENTUALLY LINE UP ESPCLY
OUT EAST BY THIS EVENING. HOWEVER LATEST MODELS REMAIN SPREAD
ACROSS THE BOARD WITH TIMING AND LOCATION ISSUES OF PRE- FRONTAL
LIFT PER SLOWNESS IN INITIALIZING WITH THE CURRENT REMNANT MCS
ATTM. APPEARS BEST SOLUTION IS TO LEAN TOWARD THE LATEST HRRR AND
GO WITH DEVELOPMENT OF MULTICELLULAR BANDS OVER THE MOUNTAINS BY
EARLY AFTERNOON PER UNIDIRECTIONAL FLOW AND THETA-E RIDGING...WITH
THIS COVERAGE OR ANOTHER LINE GRADUALLY ORGANIZING UPON HEADING
EAST INTO BETTER INSTABILITY OUT EAST THRU EARLY EVENING. THIS
AGAIN BASED ON AT LEAST SOME HEATING AS SUGGESTED BY THE LATEST
NAM WHICH BREAKS OPEN THE MID DECK LATER THIS MORNING AHEAD OF THE
BOUNDARY. THUS HAVE ADJUSTED POPS TO REFLECT A BREAK IN COVERAGE
PER WEAK SUBSIDENCE IN BEHIND THE PASSING VORT EARLY THIS
MORNING...INCREASING TO LIKELY/CAT POPS WEST EARLY/MID
AFTERNOON...THEN TRANSLATING EAST INTO EARLY THIS EVENING. THINK
COVERAGE MOVING ENOUGH TO PRECLUDE A FLASH FLOOD WATCH BUT
CERTAINLY A WIND THREAT GIVEN DECENT FCST DCAPES WHICH WILL COVER
IN THE HWO PER SWODY1 SLIGHT RISK. WILL STAY ON THE WARM SIDE OF
MOS TEMPS TODAY AS THINKING SOME INSOLATION BUT IF CLOUDS HOLD AND
CONVECTION FASTER THEN HIGH BUST POTENTIAL REMAINS.
EXPECT MAIN AXIS OF CONVECTION TO BE EAST OF THE MOUNTAINS THIS
EVENING AND MAY TAKE SOME TIME TO EXIT THE PIEDMONT AS ANOTHER WEAK
IMPULSE RIDES UP THE FRONT. THINK SEVERE POTENTIAL LIMITED BEHIND
THE INIT WAVE OF STORMS BUT LINGERING HEAVY RAIN THREAT COULD
PERSIST WHILE SHOWERS BECOME WIDELY SCATTERED OR END BEHIND THE
BOUNDARY OVER THE MOUNTAINS OVERNIGHT. THEREFORE DID DECREASE POPS
A BIT FASTER WEST THINKING CONVECTION WILL HELP TAKE DEEP MOISTURE
TO THE EAST LATE...BUT LIKELY STILL LOTS OF CLOUDS AS THE UPPER
FLOW REMAINS SW AND PARALLEL TO THE SFC FRONT. MAIN PUSH OF 85H
COOL ADVECTION WILL STILL BE WEST OF THE BLUE RIDGE LATE TONIGHT
SO KEEPING TEMPS WARMER OUT EAST AND NOT QUITE AS COOL MOUNTAINS
PER CLOUD COVER. OTRW RANGE OF LOWS FROM AROUND 60 FAR WEST TO
65-70 SE LOOKS BEST.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 300 AM EDT FRIDAY...
SHORTWAVE PIVOTS ACROSS THE CENTRAL APPALACHIANS SATURDAY AFTERNOON.
THIS WILL KEEP THE THREAT OF SHOWERS AND ISOLATED THUNDERSTORMS
GOING IN THE EAST WITH COOL POOL ALOFT. 8H TEMPS COOL TO +14C...SO
WITH SOME CLOUD COVER FROM THE COLDER AIR ALOFT...EXPECT HIGHS
CLOSE TO THE ADJMETBC WITH READINGS FROM THE MID 70S IN THE
MOUNTAINS TO THE MID 80S IN THE SOUTHEAST.
DRIER AIR WILL FINALLY WORKS IN FROM THE NORTHWEST SATURDAY NIGHT
INTO SUNDAY WITH DEWPOINTS DROPPING INTO THE UPPER 40S/LOWER 50S IN
THE HIGHER ELEVATIONS WITH MID 50S VALLEYS. THE PIEDMONT COULD SEE
SOME 50S DEWPOINTS BUT HARD TO DISPLACE THE HUMID AIRMASS ACROSS THE
CAROLINAS AS THE FLOW ALOFT STAYS WSW. PLAYED LOW TEMPERATURES
SATURDAY NIGHT FROM THE LOWER 50S IN THE MOUNTAINS TO THE LOWER 60S
IN THE EAST.
ON SUNDAY...TEMPERATURES MODERATE WITH WSW FLOW AND MORE SUNSHINE.
HEIGHTS/8H TEMPERATURES INCREASE AGAIN...HIGHS SUNDAY RETURNING TO
AROUND 80 DEGREES IN THE MOUNTAINS TO THE UPPER 80S IN THE
SOUTHEAST. LEANED TOWARDS THE ECMWFBC FOR SUNDAY NIGHT LOW
TEMPERATURES WITH VALUES FROM THE MID 50S IN THE WEST TO THE MID 60S
IN THE EAST.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
AS OF 400 PM EDT THURSDAY...
DRIER AIRMASS WILL BE DISPLACED DURING THIS PERIOD AS THE FRONT FROM
THE SHORT TERM PERIOD STALLS ACROSS THE CAROLINAS/TN VALLEY THEN
SHIFTS SLOWLY NORTH BY TUESDAY AS ANOTHER WAVE OF LOW PRESSURE
SHIFTS ACROSS IT FROM THE LOWER MISSOURI VALLEY INTO THE VA
TIDEWATER FROM MON-TUE. THIS FRONT WILL BE CLOSE ENOUGH THAT
SHOWER/TSRA CHANCES INCREASE AGAIN BY TUESDAY. ONCE THE
SHORTWAVE/ASSOCIATED SFC LOW PASS TUESDAY AFTERNOON...WEAK HIGH
PRESSURE WILL PUSH THE FRONT BACK SOUTH INTO THE GA/SC BY WEDNESDAY
AND THE AIRMASS DRIES OUT SOME...BUT THE UPPER TROUGH IS NOT AS DEEP
AS THIS WEEKENDS. OVERALL...THE TEMPS NEXT WEEK WILL AVERAGE
80S/LOWER 90S FOR HIGHS AND 60S FOR LOWS.
&&
.AVIATION /12Z FRIDAY THROUGH TUESDAY/...
AS OF 650 AM EDT FRIDAY...
INITIAL AREA OF LEFTOVER SHOWERS FROM EARLIER MCS SLOWLY FADING
ACROSS THE EAST AND SHOULD ONLY AFFECT KLYH DURING THE NEXT HOUR
OR TWO. OTRW LOOKING AT MAINLY MVFR CIGS THRU MID MORNING WITH
PERIODS OF IFR INCLUDING PATCHY FOG ESPCLY VALLEYS AND AROUND
KDAN/KLYH. NEXT BAND OF DEVELOPING CONVECTION NOW WEST OF THE
MOUNTAINS LOOKS TO ARRIVE ACROSS SE WVA AROUND MID MORNING BEFORE
WEAKENING. THUS WILL INCLUDE A VCSH AT KBLF/KLWB AND SHOW CIGS
LIFTING INTO VFR LEVELS ELSW BY LATE MORNING OR MIDDAY AS SW FLOW
STARTS TO MIX THINGS OUT. JUST HOW FAR EAST THIS BROKEN BAND OF
SHRA/TSRA MAKES IT IFFY GIVEN RATHER STABLE CONDITIONS SO WILL
HOLD OFF PUSHING COVERAGE EASTWARD FOR NOW.
HOWEVER EXPECT TO SEE MORE SHOWERS AND THUNDERSTORMS TAKE SHAPE
AHEAD OF THE UPSTREAM COLD FRONT LATE THIS MORNING INTO THE
AFTERNOON AS A DEEP UPPER LEVEL TROUGH APPROACHES THE AREA. WILL
BE LOOKING AT A FEW STRONG STORMS TO START THE AFTERNOON...AND
EXPECT THAT THESE STORMS WILL FORM INTO A LINE OR TWO JUST AHEAD
OF THE COLD FRONT AS IT ENTERS THE PIEDMONT REGION DURING EARLY
EVENING. THESE STORMS WILL BE CAPABLE OF PRODUCING STRONG WINDS
ALONG WITH PERIODIC MVFR/IFR THIS AFTERNOON. THEREFORE GIVEN
EXPECTED COVERAGE WILL INCLUDE CONVECTIVE MENTION AS PREVAILING
FROM WEST TO EAST STARTING THIS AFTERNOON. THUNDERSTORM ACTIVITY
IS EXPECTED TO END ACROSS THE AREA AS THE FRONT EXITS TO THE EAST
DURING LATE EVENING...AT WHICH POINT DRIER AIR ASSOCIATED WITH
HIGH PRESSURE WILL RESULT IN VFR CONDITIONS HEADING INTO THE EARLY
PART OF NEXT WEEK.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...JH/NF
NEAR TERM...JH
SHORT TERM...KK
LONG TERM...WP
AVIATION...JH/KM/NF
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
1028 AM MDT FRI AUG 10 2012
.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 300 AM MDT FRI AUG 10 2012
MODELS CONTINUE TO SHOW EMBEDDED WAVES IN THE MOIST FLOW WHICH
COMBINING WITH AFTERNOON HEATING WILL BE THE FORCING MECHANISMS FOR
CONVECTION TODAY. RUC13 SHOWS THE BEST DYNAMICS MOVING ACROSS THE
EASTERN UTAH THIS MORNING INTO WEST-CENTRAL COLORADO BY THIS
AFTERNOON. EXPECT ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS TO
DEVELOP ACROSS THE ENTIRE FORECAST AREA...WITH THE BEST CHANCE OF
LOCALLY HEAVY RAIN ACROSS SOUTHERN AND EXTENDING NORTH ACROSS
CENTRAL SECTIONS TODAY. GUSTY OUTFLOW WINDS TO 50 MPH ARE ALSO
POSSIBLE NEAR STORMS ESPECIALLY ACROSS CENTRAL AND NORTHERN
SECTIONS.
MORE ENERGETIC TROF MOVING INTO THE PACIFIC NORTHWEST LATE THIS
EVENING WILL BE PUSHING ACROSS THE NORTHERN ROCKIES BY THIS TIME
TOMORROW NIGHT. AS IT DOES SO THE UPPER HIGH WILL BE SUPPRESSED
SOUTH OF THE 4 CORNERS REGION AND BRINGING IN SOME STRONGER
WESTERLY FLOW AS THE GRADIENT TIGHTENS. THE GOES DERIVED SATELLITE
IMAGERY THIS MORNING IS SHOWING GOOD MOISTURE OVER SOUTHERN
CALIFORNIA/SOUTHERN NEVADA AND THE 320K MOISTURE TRANSPORT VECTS
SHOW THIS MOISTURE BEING PULLED INTO OUR CWA AS IT GETS CAUGHT UP
IN THE FASTER WESTERLIES. THERE IS NO DISTINCT OR STRONG FORCING
FOR ASCENT EVIDENT IN THE SHORT TERM MODELS OVERNIGHT. HOWEVER
BOTH GFS/NAM SHOW PWATS SURGING THROUGH THE EARLY MORNING HOURS
AND POT VORT MOVING ALONG THE NORTHERN BORDER AS UPPER JET MAX
APPROACHES SO THINK THERE WILL BE SOME LINGERING CONVECTION TO
DEAL WITH AND BOOSTED POPS SLIGHTLY AND FAVORED ACROSS THE
NORTHERN 1/3 OF THE CWA.
WITH MOISTURE IN PLACE SATURDAY ADDED DYNAMICS FROM AN UPPER LEVEL
SPEED MAX MOVING OVER NORTHERN COLORADO SHOULD LEAD TO ANOTHER
ACTIVE DAY...THOUGH MODELS ARE A LITTLE DIFFERENT ON TIMING AND
COVERAGE. NAM SOLN PVU FIELDS SHOW THE SHORT WAVE ENERGY DIPPING
INTO NORTHERN COLORADO EARLY IN THE DAY AS IT HAS A STRONGER SYSTEM
OVER THE NORTHERN ROCKIES...GFS NOT DEEPENING THE SYSTEM QUITE AS
MUCH AND KEEPS ANY SHORT WAVE FORCING JUST NORTH OF OUR BORDER. BY
AFTERNOON HOWEVER BOTH MODELS HAVE UPPER LEVEL DIVERGENCE OVER OUR
CENTRAL CWA AND WEAK SUBSIDENCE FILTERING INTO THE NORTH. THE
INHERITED POPS FOR SATURDAY COVERED THIS WELL AND MADE JUST A FEW
TWEAKS UPWARD WITH SLIGHT HIGHER CONFIDENCE. STILL CHANCE OF HEAVY
RAINFALL BUT STORM MOTIONS WILL BE ON THE INCREASE WHICH MAY ENHANCE
THE OUTFLOW WIND THREAT. TEMPERATURES SHOWING DIVERGING TREND IN
GUIDANCE WITH NAM LOWERING DUE TO BEING MORE ACTIVE. USED A BLEND
BUT GAVE MORE WEIGHT TO THE WARMER GUIDANCE ATTM.
.LONG TERM...(SATURDAY NIGHT THROUGH THURSDAY)
ISSUED AT 300 AM MDT FRI AUG 10 2012
AS THE FLOW BECOME MORE NORTHWESTERLY IN THE WAKE OF THE NORTHERN
SYSTEM DRIER AIR LOOKS TO FILTER INTO THE CWA SATURDAY NIGHT WITH
PWATS KNOCKING BACK TO UNDER .75 OVER ALL BUT THE FAR SOUTHWESTERN
PORTION OF THE CWA. THIS SHOULD ALLOW CONVECTION TO TAPER OFF
OVERNIGHT AND LEAD TO COOLER LOW TEMPERATURES. THIS DRY AIR WILL BE
IN PLACE FOR ONLY A SHORT TIME AS PWATS LOOK TO REBOUND BY LATE
SUNDAY AS THE UPPER HIGH CENTERS OVER THE SOUTHERN HIGH PLAINS. WITH
A LATE MOISTURE PUSH SOME STORMS MAY MAKE IT INTO THE VALLEYS BUT
FOR THE MOST PART THINK MOST STORM WILL BE MORE ROOTED TO THE
TERRAIN.
NOT MUCH CHANGE IN THE WEATHER PATTERN INTO THE EXTENDED PERIOD...WITH
SOUTHERLY MOIST FLOW CONTINUING INTO THE EARLY WORK WEEK WITH A
CHANCE OF AFTERNOON AND EVENING THUNDERSTORMS EXPECTED EACH DAY
THROUGH WEDNESDAY. MODELS ARE HINTING AT THE RIDGE BUILDING TO OUR
WEST BY THURSDAY WHICH WOULD GENERATE SLIGHTLY DRIER CONDITIONS BY
LATE IN THE WEEK WITH A DECREASING THREAT OF SHOWERS AND
THUNDERSTORMS. EXPECT SEASONABLY WARM TEMPERATURES THROUGH THE
EXTENDED PERIOD.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1028 AM MDT FRI AUG 10 2012
EXPECT OCCASIONAL MVFR CONDITIONS AT KEGE AND KASE THIS AFTERNOON
AND EVENING AS SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS
DEVELOP OVER AND NEAR THE MOUNTAINS. LOCAL HEAVY RAIN IS POSSIBLE
ALONG WITH WIND GUSTS TO 45 MPH. THUNDERSTORMS WILL AFFECT THE
VALLEYS AFTER 20Z. THE GREATEST AREAL COVERAGE OF SHOWERS AND
THUNDERSTORMS WILL BE OVER SOUTHWEST CO AND SOUTHEAST UT.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...NONE.
UT...NONE.
&&
$$
SHORT TERM...15/MPM
LONG TERM...MPM
AVIATION...CC
AREA FORECAST DISCUSSION
NWS DES MOINES IA
1221 PM CDT FRI AUG 10 2012
...UPDATED AVIATION DISCUSSION...
.SHORT TERM /TODAY/...
MAIN FOCUS TODAY WILL BE ON CLOUD COVER AND TEMPERATURES FOR THE
NEAR TERM. CWA TO REMAIN BENEATH CYCLONIC FLOW ALOFT...WITH WEAK CAA
EXPECTED THROUGHOUT THE DAY. SOME LOW LEVEL MOISTURE RESULTING IN AN
AREA OF LOW STRATUS CONTINUES TO DEVELOP OFF TO THE NORTHEAST OF THE
CWA...WITH MODEL PROGGING THIS AREA OF STRATUS TO CONTINUE TO
SPREAD/ADVECT INTO THE NORTHERN/EASTERN HALF OF THE CWA THROUGH
SUNRISE. HRRR MODEL AND GOES-R WRF FORECAST BOTH HANDLING THE
DEVELOPMENT OF THIS STRATUS WELL AND HAVE TAILORED SKY GRIDS TOWARD
THE MODEL/SATELLITE PRODUCT TRENDS. EXPECT STRATUS TO LIFT/BREAK UP
TOWARD MID/LATE MORNING ACROSS THE AREA...WITH RESULTANT MID LEVEL
CU FIELD POSSIBLE. OTHERWISE MUCH DRIER TO MOVE INTO THE CWA WITH
DEWPOINTS EXPECTED TO CONTINUE TO DROP TO AROUND 50 POSSIBLY EVEN
INTO THE 40S WITH DRIER AIR MIXING DOWN AND ADVECTING INTO THE CWA
IN NORTHERLY FLOW. WITH THE CAA...EXPECT TEMPS TO BE A FEW DEGREES
COOLER THAN YESTERDAY WITH HIGHS MAINLY IN THE UPPER 70S TO AROUND
80.
.LONG TERM /TONIGHT THROUGH THURSDAY/...
CANADIAN HIGH PRESSURE MOVING INTO THE NORTHERN PLAINS EARLY THIS
MORNING WITH TEMPERATURES DIPPING INTO THE LOW TO MID 40S OVER THE
SOUTHEAST QUADRANT. THIS SYSTEM WILL SETTLE SOUTH TODAY AND BE
STRETCHED OVER MUCH OF THE CENTRAL AND NORTHERN PLAINS TONIGHT.
WHILE SOME MODIFICATION OF TEMPERATURES IS EXPECTED...SHOULD HAVE
OVERNIGHT LOWS TONIGHT TOUCHING THE MID 40S AT A FEW LOCATIONS
ACROSS THE NORTH AND INTO THE LOW TO MID 50S ELSEWHERE. THE CLOSED
UPPER LOW THAT AFFECTED THE AREA ON THURSDAY WILL BE SHIFTING SLOWLY
NORTHEAST ACROSS THE CENTRAL GREAT LAKES THROUGH MID DAY SATURDAY
BEFORE GAINING STEAM SATURDAY NIGHT AS ANOTHER CLOSED UPPER LOW
MOVES INTO CENTRAL CANADA. THIS WILL ALLOW A TRANSITION TO A MORE
PROGRESSIVE NORTHWEST FLOW THAT WILL PERSIST THROUGH MUCH OF THE
EXTENDED.
A FAIRLY SIGNIFICANT SYSTEM WILL ARRIVE OVER THE PACIFIC NW LATE
TODAY THEN MOVE ACROSS THE ROCKIES AND PRODUCE LEE SIDE CYCLOGENESIS
INTO SATURDAY. SATURDAY WILL BE ANOTHER PLEASANT DAY AND EXPECT
TEMPERATURES TO BE NEAR THE HIGH END OF GUIDANCE WITH DRY SFC AIR
HEATING UP EFFICIENTLY. MID LEVEL THETA-E ADVECTION WILL COMMENCE
SATURDAY NIGHT WITH THE INITIAL WAVE BEING SPENT ON MID LEVEL
SATURATION. GULF MOISTURE WILL BREAK FREE AND BEGIN TO STREAM
NORTHWARD SATURDAY NIGHT AS WELL WITH THE MOISTURE ADVECTION
ARRIVING LATE AIDED BY AN INCREASING LOW LEVEL JET APPROACHING 40
KTS. THE COMBINATION OF THE MULTI LEVEL KINEMATICS AND
THERMODYNAMICS WILL RESULT IN A DEEPLY FORCED SYSTEM WITH SHOWERS
AND THUNDERSTORMS ARRIVING OVER THE WEST AFTER MIDNIGHT. ADDITIONAL
CHANCES WILL CONTINUE SUNDAY AND SUNDAY NIGHT WITH AS THE SECOND
SEGMENT OF THE UPPER LEVEL SYSTEM ARRIVES ALONG WITH THE SFC LOW
REFLECTION. GENERAL AGREEMENT DEVELOPING THAT THE SFC LOW WILL SHIFT
EAST ACROSS SOUTHERN IA AND WOULD ALLOW A PORTION OF THE WARM SECTOR
TO LIFT INTO THE STATE. HIGH VARIABILITY POSSIBLE WITH HIGH
TEMPERATURES ON SUNDAY WHERE HIGHS COULD STRUGGLE IN THE 60S UNDER
INCREASING CLOUDS AND MORE PROLONGED PRECIPITATION WHILE RISING WELL
INTO THE 80S SOUTH WHERE SOME SUN COULD BE POSSIBLE. THIS COULD LEAD
TO AN AREA OF SFC BASED THUNDERSTORMS AND AN AREA WITH SEVERE
POTENTIAL. PRECIPITATION CHANCES CONTINUE OVER MAINLY THE EAST
SUNDAY EVENING BEFORE ENDING.
THE REMAINDER OF THE EXTENDED IS HIGHLIGHTED BY SEVERAL IMPULSES
RIPPLING THROUGH THE NW FLOW WHILE A DEEP UPPER LEVEL LOW DROPS INTO
ALBERTA AND MANITOBA BY MID WEEK. OVERALL TIMING BECOMES DIFFICULT
UNDER THESE SITUATIONS BUT GENERAL CONSENSUS IS A WEAK WAVE ARRIVING
TUE NIGHT INTO WED WITH A MORE SIGNIFICANT SYSTEM IMPACTING THE AREA
TOWARD THE END OF THE PERIOD AS ENERGY ASSOCIATED THE SOUTHERN
CANADA SYSTEM ARRIVES.
&&
.AVIATION...10/18Z
BAND OF MVFR AND IFR STRATUS WHICH AFFECTED SITES EARLY THIS MORNING
WILL CONTINUE TO DIMINISH...LIFTING TO VFR CEILINGS. WINDS WILL BE
GUSTY IN THE AFTERNOON BUT WILL DIMINISH NEAR 00Z. HIGH PRESSURE
WILL PUSH INTO REGION...WITH WINDS REMAINING PRIMARILY FROM THE
NORTH...AND CEILINGS WILL REMAIN VFR THROUGH REMAINDER OF PERIOD.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM...BEERENDS
LONG TERM...DONAVON
AVIATION...AWB
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
450 PM EDT FRI AUG 10 2012
.Forecast Update...
Issued at 445 PM EDT Fri Aug 10 2012
Updated the forecast to include 20-30% chance of rain showers over
southern Indiana and north central Kentucky this evening. A line of
showers moving south across Indiana was noted on radar early this
evening, and it looks like the line will hold together into at least
northern portions of the area. The 17Z HRRR depicts this line well
and shows it dissipating around sunset with the lack of
heating/instability.
&&
.Short Term (Today through Saturday)...
Issued at 307 PM EDT Fri Aug 10 2012
Surface cold has now cleared our forecast area. Cooler and somewhat
drier air continues to mix in from the northwest. The colder air
aloft has resulted in steep low-level lapse rates which is resulting
in a fairly extensive area of stratocumulus. The stratocu should
hang around for the next few hours and then begin to dissipate after
sunset. Regional radars do show a few light showers/sprinkles to
our north along the I-70 corridor. These will continue to move
south and may clip a few of our northern Indiana counties this
afternoon before they also dissipate after sunset. Temperatures
will likely top off this afternoon in the upper 70s to the lower 80s
and then slide off back into the 60s later this evening.
For the overnight period, latest suite of model data continue to
show plenty of cool air advection across the region. Model-time
height cross sections show some low-level moisture lingering across
the northeast sections of the forecast area. Probably will see a
gradient clouds across the region with mostly clear skies across the
west/southwest with partly cloudy skies across the
northeast/Bluegrass. As for low temps, we`ll likely see
temperatures fall into the mid-upper 50s in the north with upper 50s
to the lower 60s in the south. We generally weighted temps closer
to the weighted model consensus which has statistically done well.
Saturday looks to be a pleasant day across the Ohio Valley with
partly to mostly sunny skies as deep northwesterly flow continues
across the region. Temperatures will be quite comfortable with
highs in the upper 70s in the east with lower 80s in the central and
western sections. Mostly clear skies are expected for Saturday Night
with lows generally in the mid-upper 50s.
.Long Term (Sunday through Friday)...
Issued at 300 PM EDT Fri Aug 10 2012
A distinct pattern change will be fully in place by early this
weekend. A broad longwave trough is forecast to lie over the upper
midwest and the Great Lakes, with ridging pushed farther west across
the Intermountain West.
No excessive heat or bouts with high humidity are expected for
basically the next week as rich Gulf moisture is forecast to remain
across the southern states. On Sunday, the deep cyclone now over
eastern Michigan is expected to slowly move northeast into Quebec.
At the same time, another compact 500mb low will slide southeast
across the Missouri Valley. Both the NAM and the GFS forecast weak
low pressure to develop over Illinois Monday afternoon and move east
across the Commonwealth overnight. Although this system will lack
any robust moisture return, upper air divergence associated with the
front exit region of the upper jet may provide enough upper air
support for scattered thunderstorms during the late Monday through
early Tuesday period.
High temperatures will warm a bit from Sunday through Monday, with
Monday`s highs in the mid to upper 80s expected to nearly match the
climatological normal for mid-August.
The ECMWF is nearly alone in its forecast of scattered showers on
Wednesday. The preferred GFS depicts the Lower Ohio Valley within a
a dry northerly flow on the backside of a departing system over
western New England.
Expect a cooldown once again beginning Tuesday afternoon, with mild
temperatures continuing through Thursday. A deep cyclone forecast
north of the upper midwest on Thursday will bring a cold front and a
chance of storms for late Thursday and Friday.
&&
.Aviation (18Z TAF issuance)...
Issued at 104 PM EDT Fri Aug 10 2012
Surface cold front has passed through the terminals this morning.
Fairly thick deck of cold air stratocumulus is trailing behind the
front and will lead to cigs that remain above VFR thresholds.
Northwest winds of 8-10kts will be possible this afternoon at KSDF
and KLEX...a gust of 15-17kts will be possible at times. Further
south at KBWG, the gradient is a little weaker so only northwesterly
winds of 5-8kts is expected.
VFR conditions are expected this evening and through much of the
overnight hours. There is potential for more low clouds to move
back into the region tonight along with the possible development of
some patchy fog. KLEX and KBWG seem to be most susceptible to the
patchy fog threat with a period of MVFR visibilities being possible
between 11/07-13Z.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
KY...NONE.
$$
Update...........AMS
Short Term.......MJ
Long Term........JSD
Aviation.........MJ
AREA FORECAST DISCUSSION
NWS CARIBOU ME
253 PM EDT FRI AUG 10 2012
.SYNOPSIS...
A STATIONARY FRONT NEAR THE COAST WILL GRADUALLY MOVE NORTH
ACROSS THE REGION AS A WARM FRONT TODAY AND TONIGHT. LOW PRESSURE
WILL PASS TO THE WEST OF THE STATE SATURDAY.
&&
.NEAR TERM /THROUGH SATURDAY/...
STRONG LOW PRESSURE IS EXPECTED TO MOVE THROUGH THE GREAT LAKES
TONIGHT INTO SATURDAY. EXPECT HEAVIER PRECIPITATION ACROSS THE
NORTH TONIGHT IN ADVANCE OF PRIMARY LOW THEN FOCUS WILL SHIFT TO
COAST SATURDAY AS SECONDARY WAVE DEVELOPS ALONG COAST. FOR POPS
HAVE USE THE RUC13 INTO EARLY EVENING THEN TRANSITION OF GFS LATER
IN EVENING THEN TO MODEL BLEND OF THE NAM12...GFS40...SREF...CMCREG
AND ECMWF. WILL ALSO BLEND THE SAME GUIDANCE FOR QPF EXCEPT USE
THE NAM80. WILL MAKE SOME MANUAL ADJUSTMENTS TO SMOOTH
PRECIPITATION AREAS. FOR TEMPERATURE AND DEW POINT USED GMOS AND
WILL ADJUST MAXIMUM TEMPERATURE A FEW DEGREES HIGHER SATURDAY.
&&
.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/...
A CLOSED H5 LOW OVER SOUTHERN QUEBEC OPENS UP AND LIFTS INTO THE
NORTHERN CANADIAN MARITIMES. A DISTURBANCE ROTATING AROUND THE H5
LOW COULD BE THE TRIGGER FOR SUNDAY AFTERNOON AND EVENING
THUNDERSTORMS. WEATHER CONDITIONS IMPROVE SUNDAY NIGHT AND MONDAY
AS THE LOW MOVES TO THE NORTHEAST OF MAINE.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
THE EXTENDED MODELS ARE CONTINUE TO DISAGREE ON A SYSTEM MOVING
THROUGH THE MID-WEST AT THE START OF THE PERIOD...HOWEVER ARE IN
GOOD GENERAL AGREEMENT ELSEWHERE THROUGH MOST OF THE PERIOD.
THE GFS IS SHOWING A LOW PRESSURE SYSTEM OVER ERN QUEBEC WITH ITS
FRONT WRAPPED AROUND THE LOW THROUGH NRN ME...THEN OUT ACROSS THE
MARITIMES. A WEAK HIGH PRESSURE RIDGE BUILDING NORTH ALONG THE
ATLANTIC COAST STATES. A LOW PRESSURE SYSTEM OVER THE SE OF JAMES
BAY...WITH A FRONTAL SYSTEM EXTENDING SOUTH THROUGH THE LAKE
MICHIGAN...TO A SECOND LOW OVER CHICAGO...THEN SOUTH TO ERN TEXAS.
THE ECMWF HAS THE LOW OVER SRN JAMES BAY...A LOW OVER ST
LOUIS...ANOTHER OVR ERN TEXAS...IT DOESN`T SUPPORT THE FRONTAL
SYSTEM TROUGH THE GREAT LAKES TO ST LOUIS. THE GFS SHOW BETTER
UPPER LEVEL SUPPORT WITH A SHORTWAVE DIGGING SOUTH TO NRN LA. THE
ECMWF DIGS THE SHRTWV TO SRN MO. TUESDAY MORNING THE GFS DEEPENS
THE LOW OVER CHICAGO AND MOVES IT EAST TO DETROIT. MAINTAINS THE
FRONT EXTENDING SOUTH TO WRN LA WITH A COUPLE MINOR LOWS. THE
ECMWF SHOWS SOME DEVELOPMENT OF THE LOW OVER ST LOUIS...MAINTAINS
IT NEARLY STATIONARY. THIS TREND CONTINUE TO TUESDAY EVENING...THE
GFS DEEPENS THE LOW FARTHER AND MOVES IT EAST TO THE ERN GREAT
LAKES REGION. THE SHORTWAVE TO NRN FL. THE GFS ALSO SHOWING GOOD
COLD AIR ALOFT TO SUPPORT THE SFC DEVELOPMENT. THE ECMWF CONTINUE
TO SHOW DEVELOPMENT OF THE SYSTEM...NOT TO THE EXTEND OF THE GFS.
SHORT WAVE SUPPORT HAS NO SIGNIFICANT CHANGE FROM PREVIOUS. BY
WEDNESDAY MORNING THE CONTRAST CONTINUES. THE GFS FURTHER DEEPENS
THE LOW OVER THE ERN GREAT LAKES. THE FROTN EXTENDING THROUGH SRN
NEW ENGLAND TO A SECOND LOW OVER DELMARVA. A DEEP SHORT WAVE
EXTENDING TO NRN FL...THE UPPER RIDGE BUILDING TO SRN HUDSON BAY.
THE ECMWF CONTINUE TO SHOW A DISORGANIZED SYSTEM MOVING THROUGH
NEW ENGLAND. THE SHORTWAVE TROUGH FILLING....AND NO SIGNIFICANT
RIDGE. BOTH MODELS ARE SHOWING A NEW LOW MOVING INTO WRN PLAINS
FROM CANADA TO NRN TX. THROUGH THURSDAY EVENING THE GFS MAINTAINS
THE LOW OVR THE ERN GREAT LAKES MOVES IT EAST TO SOUTHCOAST...THE
SFC AND 500MB LOW VERTICALLY STACKED. A SHARP UPR LVL RIDGE
THROUGH THE CNTRL GREAT LAKES. THE NEW LOW EAST TO SRN HUDSON
BAY...ITS FRONT SOUTH TO NRN TX. THE ECMWF CONTINUE TO SHOW A
DISORGANIZED SYSTEM WITH THE LOW MOVING EAST THROUGH QUEBEC INTO
THE WRN MARITIMES BY THURSDAY EVENING. THE NEW LOW THE SAME AS THE
GFS. BY END OF PERIOD. THE GFS MAINTAINS THE COLD LOW IN THE GULF
OF MAINE...THE ECMWF CONTINUES THE COLD LOW IN THE WRN MARITIMES.
THE NEW LOW ON BOTH MODELS OVR SRN HUDSON BAY...WITH A COLD FRONT
EXTENDING SOUTH THROUGH THE CNTRL GREAT LAKES. THRU KY...AR...INTO
TX. BOTH MODELS SHOW MINOR LOWS ALONG THE BOUNDARY.
THE GFS AND ECMWF CONTINUE TO DISAGREE ON THE FIRST
SYSTEM...TODAY THERE WAS A MORE PRONOUNCED DIFFERENCES IN THE
UPPER LEVEL GUIDANCE THAN IN PREVIOUS RUNS.
LOADED GMOS WITH MINOR SMOOTHING OF THE SKY AND POP GRIDS.
ADJUSTED POPS DOWN WHERE CLOUD COVER DID NOT SUPPORT PCPN. LOADED
NAWAVE 4 FOR SEAS IN THE COASTAL WATERS. PLUS 25 PERCENT TO WNDS
FOR GUST OVR COASTAL WATERS...15 PERCENT OVER LAND.
&&
.AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...
NEAR TERM: EXPECT IFR CONDITIONS DUE TO LOW CEILINGS NORTH AND
LOW CEILING AND FOGS SOUTH.
SHORT TERM: IFR/MVFR CIGS AND VSBYS WILL BE POSSIBLE AT TAF SITES
SATURDAY NIGHT...EARLY SUNDAY MORNING AND AGAIN SUNDAY NIGHT IN
SHOWERS...THUNDERSTORMS AND PATCHY FOG.
&&
.MARINE...
NEAR TERM: HAVE BLENDED THE NAM12 AND GFS40 FOR WIND GRIDS THEN
REDUCED BLENDED VALUE BY 20 PERCENT TO ADJUST FOR STRONG MARINE
LAYER OVER COLDER SEA SURFACE TEMPERATURE. FOR WAVES: SOUTHERLY
FETCH AREA TO DEVELOP THIS EVENING SOUTH AND EAST OF NEW ENGLAND.
EXPECT THIS AREA TO RESULT IN SOUTHERLY WAVE GROUP 170/7 SECONDS
BASE ON WNA SPECTRAL. THINK WNA OVER ESTIMATING THIS GROUP WITH
SURFACE WIND TOO HIGH. SECONDARY LONG PERIOD WAVE GROUP FROM 140/9
SECONDS 1-2 FEET VALID BASED ON SPECTRAL DENSITY FROM 44027. WILL
USE SWAN/NAM WAVES AND REDUCE BY 1 FOOT THROUGH PERIOD.
SHORT TERM: WINDS AND WAVES ARE EXPECTED TO REMAIN BELOW SCA
CRITERIA SUNDAY AND MONDAY.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...MIGNONE
SHORT TERM...OKULSKI
LONG TERM...NORTON
AVIATION...MIGNONE
MARINE...MIGNONE/OKULSKI
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
414 PM EDT FRI AUG 10 2012
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 410 PM EDT FRI AUG 10 2012
WV IMAGERY AND RUC ANALYSIS INDICATED A MID/UPPER LEVEL LOW OVER SE
LOWER MI. AN EXTENSIVE PCPN SHIELD PERSISTED ON THE NW FLANK OF THE
LOW ASSOCIATED WITH THE STRONGER 800-700 MB FGEN/DEFORMATION.
TONIGHT...SATELLITE TRENDS AND MODELS KEEP ANY PCPN ASSOCIATED WITH
THE SFC/MID LEVEL LOW EAST OF THE CWA.SFC HIGH PRES RIDGE WILL DRIFT
E TOWARD UPPER MI TONIGHT...BUT ONLY CLOSE ENOUGH FOR JUST THE FAR W
TO SEE LIGHT/CALM WIND AND GOOD RADIATIONAL COOLING CONDITIONS. PWAT
VALUES OVER THE WEST FALL INTO THE 0.30 TO 0.50 INCH RANGE. A
TIGHTER PRES GRADIENT TO THE EAST WILL MAINTAIN STRONG ENOUGH BNDRY
LAYER WINDS TO KEEP TEMPS FROM FALLING OFF AS MUCH. SOME MID OR HIGH
CLOUDS OVER THE E WILL ALSO LIMIT TEMP DROP. GUIDANCE TEMPS WERE
REASONABLE WITH TEMPS FALLING OFF INTO THE LOWER 40S INLAND
WEST...ESPECIALLY IN USUAL COLD SPOTS.
SATURDAY...AS THE LOW LIFTS SLOWLY TO THE NE THROUGH SRN
ONTARIO...NRLY WINDS WILL ONLY GRADUALLY DIMINISH.
WITH 850 MB TEMPS AROUND 9C...MAX READINGS INTO THE LOWER TO MID 70S
ARE EXPECTED. FCST SOUNDINGS AND DEEPER MIXING SHOW POTENTIAL FOR
DEWPOINTS TO DRAMATICALLY(AOB 40)INLAND. SO...ADJUSTED DEWPOINTS
TOWARD LOWER END NAM GUIDANCE WITH AT LEAST LOWER 40S WITH MIN RH
VALUES AOB 35 PCT.
A HIGH RISK OF RIP CURRENTS REMAINS TONIGHT INTO SATURDAY.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 410 PM EDT FRI AUG 10 2012
THE LATE SUMMER PATTERN WILL BE IN FULL SWING THROUGH THE LONG TERM
AS DEEP TROUGHING SLOWLY DEVELOPS OVER EASTERN CANADA. AS A
RESULT...A SIGNIFICANT COOL-DOWN LATE NEXT WEEK IS APPEARING MORE
LIKELY WITH EACH PASSING DAY.
SATURDAY NIGHT THROUGH MONDAY...THE STACKED CLOSED LOW THAT IS
BRINGING HEAVY PRECIPITATION TO PORTIONS OF LOWER MI TODAY WILL
CONTINUE DRIFTING NORTHEAST THROUGH SATURDAY...EVENTUALLY REACHING
GEORGIAN BAY BY 00Z SUNDAY. BOTH THE NAM AND GFS CONTINUE TO
INDICATE AN ENHANCED BAND OF H7 DEFORMATION PUSHING NW INTO FAR
EASTERN UPPER MI...WITH THE NAM BEING THE MOST AGGRESSIVE. BUT GIVEN
THAT THE NAM HAS OVERDONE MOISTURE WITH THIS SYSTEM AND THAT THERE
WILL BE SIGNIFICANT DRY AIR IN PLACE ABOVE 800 MB...DO NOT THINK ANY
PRECIP WILL MAKE IT INTO THE CWA.
A BRIEF SHORTWAVE RIDGE WILL THEN MOVE ACROSS THE AREA LATE SATURDAY
NIGHT INTO SUNDAY AND BRING MOSTLY CLEAR SKIES. SOME HIGH CLOUDS MAY
REMAIN OVER THE EAST HALF AS A RESULT OF THE LEFT ENTRANCE TO A WEAK
UPPER JET ON THE BACKSIDE OF THE DEPARTING MID-LEVEL LOW. TEMPS
COULD FALL A DECENT AMOUNT ACROSS THE INTERIOR WEST HALF WITH LIGHT
WINDS...VERY DRY AIR...AND MINIMAL CLOUD COVER. HAVE DROPPED TEMPS
INTO THE LOWER FOR SOME OF THE NORMAL COLD SPOTS.
AS MENTIONED IN THE PREVIOUS FORECAST...IT APPEARS A CONVECTIVELY
INDUCED SHORTWAVE WILL DEVELOP SATURDAY NIGHT ACROSS THE NORTHERN
PLAINS. THIS WAVE IS PROGGED TO ERODE THE RIDGE AND MOVE SOUTHEAST
INTO SOUTHERN MN/NORTHERN IA BY 00Z MONDAY. MEANWHILE...A LARGER
MID-LEVEL TROUGH OVER NORTHERN SASKATCHEWAN AT 00Z SUNDAY WILL MOVE
TO THE EAST THROUGH THE WEEKEND...REACHING FAR NORTHERN QUEBEC BY
18Z MONDAY. AN EXTENSION OF THIS TROUGH AND AN ASSOCIATED COLD FRONT
SHOULD TRACK ACROSS THE CWA MONDAY AS IT PICKS UP THE SHORTWAVE IN
THE UPPER MISSISSIPPI VALLEY. THE ECMWF HAS TRENDED MUCH FASTER
WITH THE TROUGH OVER THE PAST FEW RUNS...WHILE THE GFS HAS ACTUALLY
SLOWED THE TROUGH. FOR NOW...WILL STICK WITH THE IDEA THAT IT WILL
COME THROUGH SOMETIME ON MONDAY...BEGINNING WITH THE WEST IN THE
MORNING AND ENDING WITH THE EAST IN THE LATE AFTERNOON. THE TROUGH
WILL BE STARVED OF LOW-LEVEL MOISTURE AS THE CONVECTIVE COMPLEX TO
THE SOUTH SHOULD PREVENT MOST NORTHWARD FLOW OF MOISTURE. SOME
SUNSHINE WILL MAKE IT THROUGH THE CLOUDS...ALLOWING SBCAPE VALUES TO
REACH A FEW HUNDRED J/KG. EXTRA LIFTING SUPPORT FROM WEAK LAKE
BREEZES WILL LIKELY ALLOW SOME ISOLATED TO SCATTERED SHOWERS AND A
FEW THUNDERSTORMS TO DEVELOP INLAND...MAINLY IN THE AFTERNOON. THIS
ACTIVITY WILL SPREAD EASTWARD ALONG THE FRONT BEFORE CLEARING OUT
EARLY MONDAY EVENING.
DEW POINTS WILL BE A CONCERN ON SUNDAY WITH ABUNDANT SUNSHINE AND A
SHARP TRANSITION TO DRY AIR ABOVE THE MIXED LAYER. FORECAST H8 DEW
POINTS ARE AROUND 8C...BUT QUICKLY DROP TO -10 TO -20C BY H7. WINDS
WILL BE LIGHT THOUGH...SO DECENT ENTRAINMENT OF THE DRY AIR MAY BE
LIMITED. WILL LOWER DEW POINTS TO THE UPPER 40S INTERIOR WEST IN
THE AFTERNOON.
MONDAY NIGHT THROUGH WEDNESDAY...A MID-LEVEL RIDGE WILL BEGIN TO
BUILD IN FROM THE WEST MONDAY NIGHT AND BRING MOSTLY CLEAR SKIES
THROUGH WEDNESDAY. POPS WERE REMOVED WEDNESDAY AS THE ECMWF...WHICH
HAD POPS IN THE FORECAST YESTERDAY...HAS LINED UP WITH THE GFS IN
SHARPENING THE RIDGE AND KEEPING THE AREA DRY.
MORE ABUNDANT MIXING DAYS COULD BE IN STORE TUESDAY AND WEDNESDAY AS
VERY DRY AIR REMAINS ABOVE THE MIXED LAYER. WEDNESDAY WILL BE OF
MORE CONCERN AS TEMPERATURES WILL RISE TO AROUND 80 AND DEW POINTS
WILL POSSIBLY FALL WELL INTO THE 50S. AS OF NOW...FORECAST MIN RH
VALUES WILL BE IN THE LOW 40S FOR THE INTERIOR WEST.
HOWEVER...MIXING MAY BE EVEN MORE AGGRESSIVE THAN CURRENTLY
FORECAST...SO RH VALUES MAY FALL INTO THE 30S. WINDS WILL REMAIN
RATHER LIGHT...LESS THAN 15 MPH...SO FIRE WX CONCERNS ARE LIMITED
RIGHT NOW.
WEDNESDAY NIGHT AND FRIDAY...A SIGNIFICANT CHANGE IN THE WEATHER
PATTERN APPEARS TO BE IN THE MAKING WEDNESDAY NIGHT. A SHORTWAVE
TROUGH CURRENTLY OVER THE GULF OF ALASKA WILL MOVE EAST THROUGH THE
SOUTHERN CANADIAN PROVINCES THROUGH THE WEEKEND WHILE PICKING UP
ENERGY AND MUCH COOLER H8 AIR FROM A POLAR VORTEX WEST OF GREENLAND.
GUIDANCE IS RATHER CONSISTENT WITH THE HANDLING OF THIS TROUGH
THROUGH WEDNESDAY NIGHT...BUT SOLUTIONS BEGIN TO DIVERGE BY
THURSDAY. THE ECMWF AND GEM BRING THE TROUGH NORTHEASTWARD MUCH
QUICKER THAN THE GFS. THE ECMWF THEN TRIES TO DEVELOP A CLOSED LOW
OVER THE CWA ON FRIDAY...RESULTING IN PLENTY OF RAIN. SOLUTIONS ARE
MUCH TOO INCONSISTENT AND DIVERGENT AT THIS POINT TO MAKE ANY SENSE
OF TIMING AND PRECIP...BUT ALL STILL HINT AT A MUCH COOLER END TO
THE WEEK...WITH HIGHS POSSIBLY AROUND 60 IN SOME PLACES ON FRIDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 159 PM EDT FRI AUG 10 2012
MVFR CEILINGS AT KSAW WITH UPSLOPE WINDS WILL GIVE WAY TO VFR
CONDITONS DURING THE AFTERNOON WHEN BNDRY LAYER DRYING BECOMES MORE
SIGNIFICANT. OTHERWISE...VFR CONDITIONS WILL PREVAIL FOR THE REST OF
THE FCST PERIOD. WINDS WILL BE GUSTY TODAY...ESPECIALLY AT KSAW WHERE
GUSTS TO AROUND 25KT ARE EXPECTED DUE TO FAVORABLE WIND DIRECTION
AND CLOSER PROXIMITY TO DEPARTING SYSTEM.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 410 PM EDT FRI AUG 10 2012
EXPECT THE STRONGEST WINDS DURING THE FCST PERIOD TO OCCUR TONIGHT
THROUGH SAT UNDER RELATIVELY TIGHT PRES GRADIENT BTWN LOW PRES DRIFTING
NNE INTO SRN ONTARIO AND HIGH PRES DRIFTING E TOWARD THE UPPER
LAKES. CLOSER TO APPROACHING HIGH...WINDS WILL BE LIGHTEST OVER WRN
LAKE SUPERIOR... GENERALLY 10-20KT. OVER THE E...NNE WINDS WILL BE
MOSTLY IN THE 15-25KT RANGE. WINDS WILL SLOWLY DIMINISH TONIGHT INTO
SAT...BUT WINDS WILL REMAIN AOA 20 KT OVER ERN LAKE SUPERIOR TIL LATE
SAT. WINDS SUN THRU TUE WILL BE MOSTLY 15KT OR LESS AS ONLY WEAK
SYSTEMS AFFECT THE AREA. A FALL-LIKE LOW PRESSURE SYSTEM AND FRONT
MOVING THROUGH LAKE SUPERIOR THURSDAY INTO FRIDAY COULD BRING
STRONGER NW WINDS INTO THE 20-30 KT RANGE.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...TK
AVIATION...JLB
MARINE...JLB
AREA FORECAST DISCUSSION
NWS RALEIGH NC
206 PM EDT FRI AUG 10 2012
.SYNOPSIS...
A STRONG COLD FRONT WILL APPROACH OUR REGION FROM THE WEST TODAY AND
TONIGHT...THEN CROSS CENTRAL NORTH CAROLINA SATURDAY AND SATURDAY
NIGHT.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1030 AM FRIDAY...
SKIES ARE OVERCAST WITH WIDESPREAD STRATUS THIS MORNING..BETWEEN AN
UPPER DISTURBANCE AND ASSOCIATED PRECIP DEPARTING TO THE
NORTHEAST...AND TWO MORE APPROACHING FROM BOTH THE NORTHWEST AND
SOUTHWEST LATER TODAY. A FEW LIGHT SHOWERS ARE MOVING THROUGH THE
PIEDMONT THIS MORNING...BUT OVERALL THERE IS A LULL ACROSS THE
CAROLINAS BETWEEN THE AFOREMENTIONED UPPER FEATURES. AN UPPER
LOW/SURFACE CYCLONE HAVE NOW DEVELOPED OVER THE GREAT LAKES AND THE
ASSOCIATED COLD FRONT EXTENDS SOUTH THROUGH OH/KY/TN....WITH A
STREAM OF 2 INCH PWS ACROSS THE NC/SC PIEDMONT AND COASTAL PLAIN. A
LINE OF PREFRONTAL CONVECTION IS CURRENTLY MOVING THROUGH EASTERN TN
AND WV...BUT THE DEEP LAYER FLOW IS FORECAST TO BECOME MORE
SOUTHWESTERLY AS THE UPPER TROUGH CONTINUES TO DEEPEN... AND THE
PROGRESSION OF CONVECTIVE LINE SHOULD SLOW AS IT CROSSES THE
MOUNTAINS THIS MORNING. IN FACT... HRRR FORECASTS SHOW A LINE OF
CONVECTION MOVING INTO THE WESTERN PIEDMONT CLOSER TO 00Z.
MEANWHILE...THE AFOREMENTIONED DISTURBANCE NEAR THE GULF COAST
SHOULD BE DRAWN NORTH-NORTHEASTWARD...APPROACHING THE SOUTHERN CWA
BY 00Z. WHILE A FEW SHOWERS AND STORMS WILL BE POSSIBLE THROUGH MID
AFTERNOON WITH WEAK DISTURBANCES IN THE MOIST SOUTHWESTERLY FLOW
ALOFT...WE SHOULD BE ABLE TO PUSH MORE SIGNIFICANT POPS BACK UNTIL
AFTER 21-22Z.
CONCERNING THE SEVERE THREAT THROUGH THIS EVENING...IT APPEARS THE
WIDESPREAD STRATUS MAY LINGER THROUGH MIDDAY...WITH MORNING PIREPS
CONTINUING TO REPORT 3K FT DEPTH TO THE STRATUS. VISIBLE IMAGERY
SHOWS MORE PROMINENT BREAKS IN THE CLOUDS OVER WESTERN NC AND OVER
THE COASTAL PLAIN. THUS...TWO INSTABILITY AXES MAY DEVELOP IN THESE
REGIONS...AND MODELS SUGGEST 1500 J/KG OR MORE OF MLCAPE
POSSIBLE..WITH VALUES AROUND 1000 J/KG OVER THE PIEDMONT. STRONGER
DEEP LAYER SHEAR WILL BE LOCATED WEST OF THE MOUNTAINS FOR MOST OF
THE DAY...ALTHOUGH THE MID LEVEL HEIGHT GRADIENT WILL BEGIN TO
STRENGTHEN THIS EVENING...AND THE RAP SHOWS 25-35KT OF 0-6KM BULK
SHEAR DEVELOPING OVER THE WESTERN PIEDMONT. TO THE EAST...WHERE DEEP
LAYER FLOW IS A BIT WEAKER...MORE LIKE 20-25KT OF DEEP BULK
SHEAR...MORNING RAOBS SUGGEST A BELT OF 30KT 925-850MB FLOW EXISTS
AND THE SPC MESOANALYSIS CURRENTLY SHOWS AN AXIS OF 20KT 0-1KM SHEAR
OVER THE COASTAL PLAIN. SO WHILE DEEP SHEAR MAY NOT SUPPORT
SUPERCELLULAR ACTIVITY... IT IS POSSIBLE THAT A FEW CLUSTERS OF
STORMS OR EVEN DISCRETE CELLS WITH WEAK ROTATION COULD DEVELOP THIS
EVENING. THIS IS ALL SIGNIFICANTLY DEPENDENT ON OUR DIURNAL
DESTABILIZATION AND WHETHER OR NOT CONVECTION CAN HOLD TOGETHER
SINCE THE MAIN FORCING MECHANISMS WILL NOT ARRIVE UNTIL CLOSER TO
00Z.
OTHERWISE...HAVE MADE SOME MINOR ADJUSTMENTS TO AFTERNOON
HIGHS...WITH SLIGHTLY HIGHER VALUES OVER THE EASTERN AND WESTERN
AREAS...BUT GENERALLY 84-87 SHOULD STILL BE ATTAINABLE IF BREAKS IN
CLOUDS DEVELOP BY MID AFTERNOON. -SMITH
TONIGHT...SW FLOW WILL DEEPEN OVER CENTRAL NC IN RESPONSE TO
AMPLIFYING TROUGH OVER THE EASTERN LAKES-OH VALLEY. THIS SUGGEST A
THREAT FOR SHOWERS-STORMS TO TRAIN REPEATEDLY ACROSS THE SAME
LOCATIONS. SINCE FLOW WILL BE TAPPING AN AIR MASS WITH A VERY HIGH
MOISTURE CONTENT OVER THE NORTHERN GULF...COULD SEE A MODERATE
FLASH FLOOD THREAT DEVELOP OVER CENTRAL NC OVERNIGHT. MODEL GUIDANCE
DEPICT BEST LIFT ALOFT IN ASSOCIATION WITH THE UPPER JET WHILE LIFT
BELOW 700MB WEAK AT BEST. THUS PLAN TO HAVE POPS NO HIGHER THAN
70-80 PERCENT OVER THE WEST HALF OVERNIGHT...TRENDING TO NEAR 60
PERCENT SE (WHICH MAY BE GENEROUS).
TEMPS TODAY DEPENDENT ON THE AMOUNT OF SUN THAT OCCURS. EXPECT
CONDITIONS TODAY SIMILAR TO THE PAST FEW DAYS WHERE MAX TEMPS IN THE
MID 80S COMMON. MIN TEMPS TONIGHT UPPER 60S TO LOWER 70S.
&&
.SHORT TERM /SATURDAY AND SATURDAY NIGHT/...
AS OF 315 AM FRIDAY...
SATURDAY...EXPECT SCATTERED CONVECTION TO BE ONGOING ACROSS CENTRAL
NC SATURDAY MORNING. AS AIR MASS BECOMES MARGINALLY UNSTABLE IN THE
AFTERNOON AND SURFACE COLD FRONT ENTERS THE MOUNTAINS...SHOULD SEE
AN UPTICK IN CONVECTIVE COVERAGE IN THE AFTERNOON. BULK SHEAR VALUES
30-35KTS ACROSS THE ENTIRE FORECAST AREA SUGGEST DECENT POTENTIAL
FOR ORGANIZED STORMS IN THE FORM OF BROKEN LINE SEGMENTS THOUGH
INSTABILITY MAY BE LACKING FOR SEVERE STORMS DUE TO LIMITED
INSOLATION CAUSED BY CONSIDERABLE CLOUDINESS AND SCATTERED SHOWERS.
IF PARTIAL SUN OCCURS IN THE LATE MORNING INTO THE
AFTERNOON...PROBABILITY FOR SEVERE STORMS WILL INCREASE
EXPONENTIALLY. AGAIN...DUE TO TAP OF TROPICAL MOISTURE AND DEEP SW
FLOW...COULD SEE SHOWERS-STORMS TRAIN NEWD ACROSS THE
REGION...LEADING TO POSSIBLE FLASH FLOODING EPISODE.
MAX TEMPS MAINLY IN THE MID 80S THOUGH IF SHOWERS MORE
WIDESPREAD...COULD SEE MAX TEMPS 3-5 DEGREES COOLER...ESPECIALLY
WEST HALF.
WITH PASSAGE OF LOW-MID TROUGH SATURDAY EVENING IN THE WEST...EXPECT
CHANCES FOR CONVECTION TO BEGIN TO DECREASE IN THIS REGION.
MEANWHILE DECENT CHANCES FOR SCATTERED SHOWERS-STORMS SHOULD PERSIST
THROUGH MIDNIGHT IN THE EAST. MIN TEMPS MID 60S NW TO NEAR 70-LOWER
70S SE.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
AS OF 245 AM FRIDAY...
MID/UPPER LOW EXPECTED TO BE CENTERED INVOF THE NORTHERN GREAT LAKES
REGION AND NEAR THE ONTARIO/QUEBEC BORDER 12Z SUNDAY IS EXPECTED TO
CONTINUING LIFTING NNE ON SUNDAY. THIS WILL RESULT IN FLOW ALOFT
ACROSS CENTRAL NC BECOMING MORE WESTERLY WITH DRIER AIR ALOFT
CONTINUING TO FILTER INTO THE AREA. AT THE SURFACE THE WEAK FRONT IS
EXPECTED TO WASHOUT/DISSIPATE ACROSS THE AREA ON SUNDAY INTO MONDAY.
GIVEN THIS ALONG WITH THE DEPARTURE OF THE FORCING ALOFT AND MOIST
AIR ALOFT... EXPECTED GENERALLY DRY CONDITIONS ON SUNDAY INTO MONDAY
(OUTSIDE OF POSSIBLE A FEW LINGERING SHOWERS/STORMS ACROSS THE FAR
EAST ON SUNDAY... SLIGHT CHANCE AT BEST THOUGH). CHANCE FOR POPS ARE
EXPECTED TO INCREASE BY TUESDAY INTO TUESDAY NIGHT/PERHAPS LINGERING
INTO WEDNESDAY/THURSDAY AS A LOW AMPLITUDE S/W TROUGH AND ASSOCIATED
WEAK COLD FRONT/SURFACE TROUGH MOVE ACROSS THE AREA. GIVEN TIMING
AND SOME STRENGTH DIFFERENCES WILL CONTINUE TO ONLY GO WITH A LOW
END CHANCE POPS FOR TUESDAY/TUESDAY EVENING... WITH DIURNAL SLIGHT
CHANCE POPS FOR WEDNESDAY INTO THURSDAY WITH THE REMNANT LINGERING
SURFACE TROUGH. HIGH TEMPS DURING THE PERIOD ARE EXPECTED TO
GENERALLY BE IN THE UPPER 80S TO LOWER 90S... WITH LOWS GENERALLY
RANGING FROM THE UPPER 60S TO LOWER 70S (WITH MAYBE SOME LOW TEMPS
IN THE LOWER TO MID 60S IN THE RURAL LOCATIONS AND NORTHWEST
PIEDMONT ON MONDAY MORNING).
&&
.AVIATION /18Z FRIDAY THROUGH TUESDAY/...
AS OF 200 PM FRIDAY...
LINGERING MVFR CEILINGS ACROSS CENTRAL NC WILL CONTINUE TO THIN OUT
AND IMPROVE TO VFR BY 19 TO 20Z. AIRMASS WILL THEN
DESTABILIZE...SUPPORTING SCATTERED SHOWERS AND STORMS BETWEEN 20 TO
24Z...PARTICULARLY IN THE VICINITY OF KFAY AND KRWI WHERE LEAD
SHORTWAVE DISTURBANCE RESIDES. CONVECTIVE MIXING WILL ALSO RESULT IN
OCCASIONAL BREEZY SWLY WINDS BETWEEN 15 TO 18KTS.
A SFC FRONT WILL PUSH EAST OF THE MTNS BETWEEN 03Z-06Z TONIGHT.
WESTERN PORTIONS OF THE FORECAST AREA...INCLUDING THE TRIAD
TERMINALS...ARE EXPECTED TO SEE BETTER CONVECTIVE RAIN CHANCES
WITH THE APPROACH OF THE FRONT. THE FRONT WILL THEN MOVE SLOWLY
THROUGH THE AREA SATURDAY AND SATURDAY EVENING. EXPECT BANDS OF
SHOWERS AND T-STORMS ACROSS CENTRAL NC THROUGH 18Z SATURDAY WITH
ASSOCIATED MVFR CONDITIONS.
DRIER MORE STABLE AIR WILL GRADUALLY OVERSPREAD CENTRAL NC LATE
SATURDAY NIGHT INTO SUNDAY LEADING TO IMPROVING AVIATION CONDITIONS.
MAINLY VFR CONDITIONS EXPECTED MONDAY INTO TUESDAY.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...WSS
NEAR TERM...WSS/SMITH
SHORT TERM...WSS
LONG TERM...BSD
AVIATION...CBL
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
537 PM EDT FRI AUG 10 2012
.SYNOPSIS...
A COLD FRONT WILL APPROACH FROM THE WEST THIS AFTERNOON AND SHOULD
GET HUNG UP ACROSS THE MOUNTAINS TONIGHT. THE FRONT IS EXPECTED TO
PUSH THROUGH LATE SATURDAY AND THEN SOUTH OF THE AREA ON SUNDAY.
HIGH PRESSURE WILL MOVE IN FOR THE EARLY PART OF NEXT WEEK.
MEANWHILE ANOTHER FRONT WILL APPROACH THE AREA BY MID WEEK.
&&
.NEAR TERM /THROUGH SATURDAY/...
AS OF 530 PM...A STRONG STORM HAS MOVED INTO RABUN COUNTY...AND A
LINE OF CONVECTION IS ORGANIZING OVER THE GREAT VALLEY OF TN.
HOWEVER...NOT MUCH IS HAPPENING OVER THE ERN FOOTHILLS AND PIEDMONT
ZONES ATTM AND I/VE CUT BACK POPS IN THOSE LOCATIONS FOR THE NEXT
COUPLE HOURS. THERE CONTINUES TO BE GOOD MODEL AGREEMENT THAT
CONVECTION WILL BECOME MORE WIDESPREAD THROUGH BOTH AN MCS MOVING
INTO THE NC MTNS AND CONVECTION DEVELOPING IN STRENGTHENING LLVL
CONVERGENCE ACROSS THE FOOTHILLS LATER THIS EVENING. AND THIS IS
REFLECTED WELL IN THE GRIDS.
AS OF MID AFTERNOON...VISIBLE SATELLITE IMAGERY SHOWS LOW CONVECTIVE
CLOUDS SCATTERING SUFFICIENTLY E OF THE BLUE RIDGE TO ALLOW HEATING
THAT HAS RAISED SFC-BASED CAPE INTO THE 1500-2000 J/KG RANGE ON THE
LAPS ANALYSIS. SHOWER ACTIVITY HAS DEVELOPED OVER THE CLT METRO AREA
AND ALONG THE BLUE RIDGE...WITH MORE ACTIVITY CLOSER TO THE FRONT
OVER THE CUMBERLAND PLATEAU. EXPECT SHOWERS AND STORMS TO CONTINUE
DEVELOPING AND BECOMING MORE NUMEROUS...MAINLY OVER THE MTNS AND
FOOTHILLS...THROUGH THE LATE AFTERNOON. SEVERE WEATHER REMAINS A
CONCERN WITH SOME DRY AIR ABOVE 500 MB...ALTHO IN GENERAL THE
SOUNDINGS DO NOT LOOK AS FAVORABLE AS YESTERDAY.
OVER THE NEXT 24 HOURS OR SO...THE MODELS ARE IN GOOD AGREEMENT WITH
THE EVOLUTION OF WEATHER FEATURES...AND IN PARTICULAR SHOW THE AXIS
OF THE UPPER TROF AND THE UPPER JET REMAINING TO OUR WEST. THIS WILL
ACT TO KEEP THE SURFACE FRONT HUNG UP PROBABLY OVER THE MTNS THROUGH
SATURDAY AFTERNOON. THE TREND...THEREFORE...IS TO HOLD ON TO MORE OF
A CHANCE OF SHOWER/TSTM ACTIVITY OVER A LARGER PART OF THE FCST AREA
THROUGH 00Z SUNDAY.
THE THREAT OF SEVERE STORMS WILL SLOWLY INCREASE AS BUOYANCY
AND DCAPE SLOWLY BECOME MORE FAVORABLE...WITH JUST ENOUGH SHEAR TO
PERHAPS ORGANIZE STORMS EARLY THIS EVENING. THE 4KM WRF DEVELOPS A
LINE OF STORMS OFF THE BLUE RIDGE AROUND 23Z WHILE THE HRRR BRINGS
THE LINE OF STORMS ACROSS TN AND INTO THE NC MTNS AROUND THAT TIME.
ABUNDANT LOW LEVEL MOISTURE AND ENUF UPPER FORCING WILL EXIST TO
WARRANT A LIKELY POP INTO THE EVENING HOURS. WILL KEEP POP IN THE
CHANCE RANGE OVERNIGHT AS ADDITIONAL STORMS COULD REDEVELOP AT ANY
TIME WITH THE SITUATION REMAINING UNCHANGED. TEMPS WILL REMAIN MILD.
ON SATURDAY...EXPECT THE FRONT TO BE HUNG UP OVER THE MTNS AT
SUNRISE. UNLESS EXTENSIVE CONVECTIVE DEBRIS PREVENTS IT...CONVECTION
SHOULD RE-FIRE EARLY IN THE DAY CLOSE TO THE FRONT AS IT DID TO OUR
WEST THIS PAST MORNING. UPPER DIVERGENCE...DPVA...AND PLENTY OF
MOISTURE SUGGEST ANOTHER POP IN THE LIKELY RANGE BY AFTERNOON OVER
THE PIEDMONT...AND A CHANCE UP TO THE BLUE RIDGE. A GUIDANCE BLEND
WAS USED FOR HIGH TEMPS.
&&
.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/...
AT 200 PM EDT FRIDAY...12Z GFS AND NAM STILL SOMEWHAT AT ODDS AS TO
HOW FAST THE FRONTAL BAND OF DEEP LAYER MOISTURE AND PRECIP WILL
EXIT THE FORECAST AREA OVER THE EAST. THE NAM STIL IS FASTER AND HAS
THE DEEP LAYER FRONTAL MOISTURE EAST OF THE AREA BY 00Z SUN...WHILE
THE GFS IS CONSIDERABLY SLOWER AND WETTER. THE SREF APPEARS TO
CONTINUE TO BE A GOOD COMPROMISE FOR THE SOLUTION. THE SREF KEEPS
PRECIP CHANCES OVER THE EASTERN MOST PART OF THE FORECAST AREA EARLY
ON SAT NIGHT...AND THEN MOVES THE MOISTURE/PRECIP EAST BY MIDNIGHT.
WILL ALSO SCATTER AND CLEAR THE CLOUDS FROM NW TO SE SAT NIGHT. HIGH
PRESSURE BUILDS OVER THE AREA ON SUN WHICH SHOULD PRODUCE A VERY
NICE DAY WITH DEWPOINTS MIXING OUT INTO THE 50S OVER THE MOUNTAINS
AND LOW 60S ELSEWHERE. THE HIGH SHIFTS EAST OF THE AREA ON
MONDAY...BUT ITS LINGERING INFLUENCE SHOULD ALLOW FOR ANOTHER DRY
DAY ON MONDAY. TEMPS ARE EXPECTED TO BE SLIGHTLY BELOW CLIMO ON SUN
AND NEAR CLIMO ON MON.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
AT 130 PM EDT FRIDAY...A SOMEWHAT PROGRESSIVE PATTERN APPEARS TO BE
IN STORE DURING THE MEDIUM RANGE. THE UPPER AIR PATTERN WILL
GENERALLY FEATURE A MEAN TROUGH OVER THE EASTERN U.S. WITH
INDICATIONS FROM THE LATEST 12Z GFS OF BUILDING HEIGHTS TOWARD THE END
OF NEXT WEEK OVER THE EAST. LATEST HPC/GFS GUIDANCE SUGGESTS A WEAK
COLD FRONT WILL CROSS THE REGION ON TUE ALONG WITH SCATTERED
CONVECTION. THE GFS DRIVES THE FRONT SE OF THE AREA BY WED WITH HIGH
PRESSURE BUILDING IN THROUGH THU. THUS ONLY CLIMO TYPE POPS FOR
AFTERNOON CONVECTION IN THE MOUNTAINS WED AND THU. ANOTHER FRONT
APPROACHES THE AREA ON FRI AND PER HPC WILL FORECAST CHANCE TYPE
POPS. TEMPS SHOULD BE NEAR CLIMO THROUGH THE PERIOD.
&&
.AVIATION /22Z FRIDAY THROUGH WEDNESDAY/...
AT KCLT...SCATTERED SHOWERS DEVELOPING RAPIDLY OVER THE WRN PIEDMONT
WHILE CLOUD BASES REMAIN MVFR. THIS SHOULD CONTINUE WITH A SLOW RISE
IN THE LCL THROUGH EARLY AFTERNOON...SUCH THAT CONDITIONS SHOULD
BECOME VFR BY 20Z. LOW CLOUDS WILL CONTINUE...HOWEVER...THROUGH THE
REST OF THE DAYLIGHT HOURS GIVEN THE PLENTIFUL LOW LEVEL MOISTURE.
THE LATEST GUIDANCE SUGGESTS THE BEST CHANCE FOR ANOTHER ROUND OF
THUNDERSTORMS WILL BE EARLY THIS EVENING. THERE IS ENUF FORCING TO
SUGGEST THAT STORMS ARE LIKELY...SO THE TARGET WINDOW OF 01Z TO 04Z
HAS BEEN ESTABLISHED. SOME SHOWERS COULD CONTINUE OVERNIGHT WITH THE
ACTUAL FRONT HUNG UP TO THE WEST. LOW CLOUDS SHOULD RETURN LATE
TONIGHT...RESULTING IN AT LEAST AN MVFR CEILING AFTER 11Z. MORE LOW
CLOUDS ARE POSSIBLE AGAIN SATURDAY MORNING WITH THE FRONT HUNG UP
OVER THE MTNS.
ELSEWHERE...LOW CLOUDS CONTINUE TO SCATTER OUT EARLY THIS EVENING...
WHICH WILL FINALLY ALLOW FOR SOME DESTABILIZATION. SHOWERS WILL
CONTINUE TO DEVELOP ACROSS THE MTNS THROUGH 22Z AND THEN PUSH EAST
THROUGH THE EARLY EVENING. RETURN TO LOW MVFR/IFR CIGS TONIGHT AS
FRONT SLOWS...IFR VSBY POSSIBLY MAINLY ACROSS KHKY AND KAVL WHERE
DRY AIR ALOFT WORKS IN.
OUTLOOK...A COLD FRONT WILL SLOWLY CROSS THE AREA LATE SATURDAY...
WITH DRIER HIGH PRES BUILDING IN FROM THE W THE LATTER HALF OF THE
WEEKEND. WEAK HIGH PRESSURE WILL LINGER THROUGH EARLY NEXT WEEK.
AN EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLE SHOWING THE
PERCENTAGE OF GUIDANCE MEMBERS AGREEING WITH THE SCHEDULED ISSUANCE
CATEGORY IS AVAILABLE AT FOLLOWING LINK (USE LOWER CASE)...
WWW.WEATHER.GOV/GSP/AVIATION/TABLES.HTM
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...PM
NEAR TERM...MCAVOY
SHORT TERM...LG
LONG TERM...LG
AVIATION...PM
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
241 PM EDT FRI AUG 10 2012
.SYNOPSIS...
A COLD FRONT WILL APPROACH FROM THE WEST THIS AFTERNOON AND SHOULD
GET HUNG UP ACROSS THE MOUNTAINS TONIGHT. THE FRONT IS EXPECTED TO
PUSH THROUGH LATE SATURDAY AND THEN SOUTH OF THE AREA ON SUNDAY.
HIGH PRESSURE WILL MOVE IN FOR THE EARLY PART OF NEXT WEEK.
MEANWHILE ANOTHER FRONT WILL APPROACH THE AREA BY MID WEEK.
&&
.NEAR TERM /THROUGH SATURDAY/...
AS OF MID AFTERNOON...VISIBLE SATELLITE IMAGERY SHOWS LOW CONVECTIVE
CLOUDS SCATTERING SUFFICIENTLY E OF THE BLUE RIDGE TO ALLOW HEATING
THAT HAS RAISED SFC-BASED CAPE INTO THE 1500-2000 J/KG RANGE ON THE
LAPS ANALYSIS. SHOWER ACTIVITY HAS DEVELOPED OVER THE CLT METRO AREA
AND ALONG THE BLUE RIDGE...WITH MORE ACTIVITY CLOSER TO THE FRONT
OVER THE CUMBERLAND PLATEAU. EXPECT SHOWERS AND STORMS TO CONTINUE
DEVELOPING AND BECOMING MORE NUMEROUS...MAINLY OVER THE MTNS AND
FOOTHILLS...THROUGH THE LATE AFTERNOON. SEVERE WEATHER REMAINS A
CONCERN WITH SOME DRY AIR ABOVE 500 MB...ALTHO IN GENERAL THE
SOUNDINGS DO NOT LOOK AS FAVORABLE AS YESTERDAY.
OVER THE NEXT 24 HOURS OR SO...THE MODELS ARE IN GOOD AGREEMENT WITH
THE EVOLUTION OF WEATHER FEATURES...AND IN PARTICULAR SHOW THE AXIS
OF THE UPPER TROF AND THE UPPER JET REMAINING TO OUR WEST. THIS WILL
ACT TO KEEP THE SURFACE FRONT HUNG UP PROBABLY OVER THE MTNS THROUGH
SATURDAY AFTERNOON. THE TREND...THEREFORE...IS TO HOLD ON TO MORE OF
A CHANCE OF SHOWER/TSTM ACTIVITY OVER A LARGER PART OF THE FCST AREA
THROUGH 00Z SUNDAY.
THE THREAT OF SEVERE STORMS WILL SLOWLY INCREASE AS BUOYANCY
AND DCAPE SLOWLY BECOME MORE FAVORABLE...WITH JUST ENOUGH SHEAR TO
PERHAPS ORGANIZE STORMS EARLY THIS EVENING. THE 4KM WRF DEVELOPS A
LINE OF STORMS OFF THE BLUE RIDGE AROUND 23Z WHILE THE HRRR BRINGS
THE LINE OF STORMS ACROSS TN AND INTO THE NC MTNS AROUND THAT TIME.
ABUNDANT LOW LEVEL MOISTURE AND ENUF UPPER FORCING WILL EXIST TO
WARRANT A LIKELY POP INTO THE EVENING HOURS. WILL KEEP POP IN THE
CHANCE RANGE OVERNIGHT AS ADDITIONAL STORMS COULD REDEVELOP AT ANY
TIME WITH THE SITUATION REMAINING UNCHANGED. TEMPS WILL REMAIN MILD.
ON SATURDAY...EXPECT THE FRONT TO BE HUNG UP OVER THE MTNS AT
SUNRISE. UNLESS EXTENSIVE CONVECTIVE DEBRIS PREVENTS IT...CONVECTION
SHOULD RE-FIRE EARLY IN THE DAY CLOSE TO THE FRONT AS IT DID TO OUR
WEST THIS PAST MORNING. UPPER DIVERGENCE...DPVA...AND PLENTY OF
MOISTURE SUGGEST ANOTHER POP IN THE LIKELY RANGE BY AFTERNOON OVER
THE PIEDMONT...AND A CHANCE UP TO THE BLUE RIDGE. A GUIDANCE BLEND
WAS USED FOR HIGH TEMPS.
&&
.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/...
AT 200 PM EDT FRIDAY...12Z GFS AND NAM STILL SOMEWHAT AT ODDS AS TO
HOW FAST THE FRONTAL BAND OF DEEP LAYER MOISTURE AND PRECIP WILL
EXIT THE FORECAST AREA OVER THE EAST. THE NAM STIL IS FASTER AND HAS
THE DEEP LAYER FRONTAL MOISTURE EAST OF THE AREA BY 00Z SUN...WHILE
THE GFS IS CONSIDERABLY SLOWER AND WETTER. THE SREF APPEARS TO
CONTINUE TO BE A GOOD COMPROMISE FOR THE SOLUTION. THE SREF KEEPS
PRECIP CHANCES OVER THE EASTERN MOST PART OF THE FORECAST AREA EARLY
ON SAT NIGHT...AND THEN MOVES THE MOISTURE/PRECIP EAST BY MIDNIGHT.
WILL ALSO SCATTER AND CLEAR THE CLOUDS FROM NW TO SE SAT NIGHT. HIGH
PRESSURE BUILDS OVER THE AREA ON SUN WHICH SHOULD PRODUCE A VERY
NICE DAY WITH DEWPOINTS MIXING OUT INTO THE 50S OVER THE MOUNTAINS
AND LOW 60S ELSEWHERE. THE HIGH SHIFTS EAST OF THE AREA ON
MONDAY...BUT ITS LINGERING INFLUENCE SHOULD ALLOW FOR ANOTHER DRY
DAY ON MONDAY. TEMPS ARE EXPECTED TO BE SLIGHTLY BELOW CLIMO ON SUN
AND NEAR CLIMO ON MON.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
AT 130 PM EDT FRIDAY...A SOMEWHAT PROGRESSIVE PATTERN APPEARS TO BE
IN STORE DURING THE MEDIUM RANGE. THE UPPER AIR PATTERN WILL
GENERALLY FEATURE A MEAN TROUGH OVER THE EASTERN U.S. WITH
INDICATIONS FROM THE LATEST 12Z GFS OF BUILDING HEIGHTS TOWARD THE END
OF NEXT WEEK OVER THE EAST. LATEST HPC/GFS GUIDANCE SUGGESTS A WEAK
COLD FRONT WILL CROSS THE REGION ON TUE ALONG WITH SCATTERED
CONVECTION. THE GFS DRIVES THE FRONT SE OF THE AREA BY WED WITH HIGH
PRESSURE BUILDING IN THROUGH THU. THUS ONLY CLIMO TYPE POPS FOR
AFTERNOON CONVECTION IN THE MOUNTAINS WED AND THU. ANOTHER FRONT
APPROACHES THE AREA ON FRI AND PER HPC WILL FORECAST CHANCE TYPE
POPS. TEMPS SHOULD BE NEAR CLIMO THROUGH THE PERIOD.
&&
.AVIATION /19Z FRIDAY THROUGH WEDNESDAY/...
AT KCLT...SCATTERED SHOWERS DEVELOPING RAPIDLY OVER THE WRN PIEDMONT
WHILE CLOUD BASES REMAIN MVFR. THIS SHOULD CONTINUE WITH A SLOW RISE
IN THE LCL THROUGH EARLY AFTERNOON...SUCH THAT CONDITIONS SHOULD
BECOME VFR BY 20Z. LOW CLOUDS WILL CONTINUE...HOWEVER...THROUGH THE
REST OF THE DAYLIGHT HOURS GIVEN THE PLENTIFUL LOW LEVEL MOISTURE.
THE LATEST GUIDANCE SUGGESTS THE BEST CHANCE FOR ANOTHER ROUND OF
THUNDERSTORMS WILL BE EARLY THIS EVENING. THERE IS ENUF FORCING TO
SUGGEST THAT STORMS ARE LIKELY...SO THE TARGET WINDOW OF 01Z TO 04Z
HAS BEEN ESTABLISHED. SOME SHOWERS COULD CONTINUE OVERNIGHT WITH THE
ACTUAL FRONT HUNG UP TO THE WEST. LOW CLOUDS SHOULD RETURN LATE
TONIGHT...RESULTING IN AT LEAST AN MVFR CEILING AFTER 11Z. MORE LOW
CLOUDS ARE POSSIBLE AGAIN SATURDAY MORNING WITH THE FRONT HUNG UP
OVER THE MTNS.
ELSEWHERE...LOW CLOUDS CONTINUE TO SCATTER OUT EARLY THIS EVENING...
WHICH WILL FINALLY ALLOW FOR SOME DESTABILIZATION. SHOWERS WILL
CONTINUE TO DEVELOP ACROSS THE MTNS THROUGH 22Z AND THEN PUSH EAST
THROUGH THE EARLY EVENING. RETURN TO LOW MVFR/IFR CIGS TONIGHT AS
FRONT SLOWS...IFR VSBY POSSIBLY MAINLY ACROSS KHKY AND KAVL WHERE
DRY AIR ALOFT WORKS IN.
OUTLOOK...A COLD FRONT WILL SLOWLY CROSS THE AREA LATE SATURDAY...
WITH DRIER HIGH PRES BUILDING IN FROM THE W THE LATTER HALF OF THE
WEEKEND. WEAK HIGH PRESSURE WILL LINGER THROUGH EARLY NEXT WEEK.
AN EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLE SHOWING THE
PERCENTAGE OF GUIDANCE MEMBERS AGREEING WITH THE SCHEDULED ISSUANCE
CATEGORY IS AVAILABLE AT FOLLOWING LINK (USE LOWER CASE)...
WWW.WEATHER.GOV/GSP/AVIATION/TABLES.HTM
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...PM
NEAR TERM...PM
SHORT TERM...LG
LONG TERM...LG
AVIATION...PM
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
202 PM EDT FRI AUG 10 2012
.SYNOPSIS...
A STRONG UPPER LEVEL TROUGH WILL CROSS OVER THE GREAT LAKES
TODAY...AND PUSH A COLD FRONT ACROSS THE MID ATLANTIC. THIS FRONT
WILL TRIGGER NUMEROUS SHOWERS AND THUNDERSTORMS THIS AFTERNOON AND
EVENING...WITH A FEW STORMS POSSIBLY BECOMING STRONG TO SEVERE.
ONCE THE COLD FRONT DEPARTS LATER TONIGHT INTO SATURDAY...HIGH
PRESSURE WILL ARRIVE TO PROVIDE COOLER AND DRIER CONDITIONS FOR
THE REST OF THIS WEEKEND INTO EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1200 PM EDT FRIDAY...
THE SHOWERS OVER WEST VIRGINIA ARE STILL PRESENT BUT GRADUALLY
DECAYING. NEW DEVELOPMENT OF SHOWERS AND THUNDERSTORMS HAS BEEN
DELAYED A FEW HOURS TOWARD THE MID AFTERNOON AND EVENING...AS
INSTABILITY IS CURRENTLY STILL LACKING. THE THREAT FOR SEVERE
WEATHER TODAY CONTINUES TO DIMINISH DUE TO CLOUD COVER REMAINING
QUITE THICK OVER THE AREA...BUT SOME SUNSHINE IS PEEKING THROUGH
ALONG THE BLUE RIDGE. MINOR TWEAKS WERE MADE TO THE POPS AND
TEMPERATURES TO ACCOUNT FOR THE RECENT TRENDS ON RADAR AND
SATELLITE. ALSO...WINDS WERE BUMPED UPWARD DUE TO ROANOKE AND
DANVILLE BOTH OBSERVING A GUSTY SOUTHWEST WIND DEVELOPING...WHICH
SHOULD CONTINUE THROUGH THE AFTERNOON.
AS OF 1015 AM EDT FRIDAY...
DUE TO THE DEPARTING BAND OF SHOWERS AND THUNDERSTORMS FROM LAST
NIGHT...AND ANOTHER SMALL BAND OF SHOWERS CROSSING OVER SOUTHEAST
WEST VIRGINIA AT THIS MOMENT...THERE WILL BE LOTS OF CLOUD COVER
TO ERODE OVER THE AREA FOR ANY SIGNIFICANT RISK OF SEVERE WEATHER.
THE SMALL BAND OF SHOWERS OVER WEST VIRGINIA WILL GRADUALLY
DISSIPATE AS IT CROSSES THE BLUE RIDGE IN A FEW HOURS. RECOVERING
THE INSTABILITY WILL BE THE KEY FOR TODAY. LAPSE RATES IN THE 12Z
RNK SOUNDING ARE NOT IMPRESSIVE...BUT WITH ENOUGH DAYTIME HEATING
AND DYNAMICAL SUPPORT AS THE SURFACE COLD FRONT DRAWS
CLOSER...THERE SHOULD BE SUFFICIENT SUPPORT FOR THE GROWTH OF
NUMEROUS SHOWERS AND THUNDERSTORMS LATER THIS AFTERNOON. IF ANY OF
THESE STORMS BECOME STRONG TO SEVERE...DAMAGING WINDS AND HEAVY
RAIN WILL BE THE PRIMARY THREATS.
SINCE CLOUD COVER AND BANDS OF CONVECTION WILL BE ONGOING
THROUGHOUT THE DAY...THE TEMPERATURE FORECAST IS QUITE
PROBLEMATIC. AT THIS TIME...TEMPERATURES WERE BUMPED UPWARD FOR
HIGHS WEST OF THE BLUE RIDGE DUE TO SOME BREAKS IN THE CLOUDS.
OTHER AREAS WERE KEPT CLOSE TO THE PREVIOUS FORECAST AND MOS
GUIDANCE...WITH HIGHS IN THE MID TO UPPER 70S WEST OF THE BLUE
RIDGE...AND LOWER TO MID 80S IN THE PIEDMONT. WITH REGARDS TO
POPS...A SMALL AREA OF LIKELY CHANCES WERE UTILIZED TO ACCOUNT FOR
THE DECAYING BAND OF SHOWERS OVER WEST VIRGINIA THIS MORNING.
LIKELY POPS WEST OF THE BLUE RIDGE...AND CATEGORICAL POPS OVER THE
PIEDMONT WERE PLACED THIS AFTERNOON AND EVENING...AS THERE
SHOULD BE BANDED CONVECTION FORMING ALONG AND WEST OF THE BLUE
RIDGE...AND BECOMING MORE ORGANIZED AS IT HEADS EASTWARD.
AS OF 315 AM EDT FRIDAY...
MAIN CONCERN TODAY WITH THE DEGREE OF POSSIBLE RENEWED CONVECTION
LATER ON AS THE UPPER LOW TO THE NW PROPELS A STRONG COLD FRONT TO
ALONG THE WESTERN SLOPES THIS EVENING AND EAST OF THE BLUE RIDGE
OVERNIGHT. AGAIN ONE OF THE MAIN FACTORS IS WITH JUST HOW MUCH
DEEP INSTABILITY CAN BE GENERATED THIS AFTERNOON IN THE WAKE OF
THE CURRENT MVC THAT WILL EXIT THE CWA BY DAYBREAK. THIS FEATURE
AND ITS CONVECTION HAVE BASICALLY REMOVED ANY LINGERING CAPE FROM
THU EVENING AND WILL NEED A PERIOD OF STRONG HEATING TO REGENERATE
ENOUGH INSTABILITY FOR A MORE WIDESPREAD SEVERE THREAT. LATEST
FCST SOUNDINGS DO SHOW WIND FIELDS STRENGTHENING/BACKING ALOFT
AHEAD OF THE UPSTREAM TROF THRU THIS EVENING SUGGESTING POTENTIAL
FOR BANDS OF DEEPER CONVECTION THAT MAY EVENTUALLY LINE UP ESPCLY
OUT EAST BY THIS EVENING. HOWEVER LATEST MODELS REMAIN SPREAD
ACROSS THE BOARD WITH TIMING AND LOCATION ISSUES OF PRE- FRONTAL
LIFT PER SLOWNESS IN INITIALIZING WITH THE CURRENT REMNANT MCS
ATTM. APPEARS BEST SOLUTION IS TO LEAN TOWARD THE LATEST HRRR AND
GO WITH DEVELOPMENT OF MULTICELLULAR BANDS OVER THE MOUNTAINS BY
EARLY AFTERNOON PER UNIDIRECTIONAL FLOW AND THETA-E RIDGING...WITH
THIS COVERAGE OR ANOTHER LINE GRADUALLY ORGANIZING UPON HEADING
EAST INTO BETTER INSTABILITY OUT EAST THRU EARLY EVENING. THIS
AGAIN BASED ON AT LEAST SOME HEATING AS SUGGESTED BY THE LATEST
NAM WHICH BREAKS OPEN THE MID DECK LATER THIS MORNING AHEAD OF THE
BOUNDARY. THUS HAVE ADJUSTED POPS TO REFLECT A BREAK IN COVERAGE
PER WEAK SUBSIDENCE IN BEHIND THE PASSING VORT EARLY THIS
MORNING...INCREASING TO LIKELY/CAT POPS WEST EARLY/MID
AFTERNOON...THEN TRANSLATING EAST INTO EARLY THIS EVENING. THINK
COVERAGE MOVING ENOUGH TO PRECLUDE A FLASH FLOOD WATCH BUT
CERTAINLY A WIND THREAT GIVEN DECENT FCST DCAPES WHICH WILL COVER
IN THE HWO PER SWODY1 SLIGHT RISK. WILL STAY ON THE WARM SIDE OF
MOS TEMPS TODAY AS THINKING SOME INSOLATION BUT IF CLOUDS HOLD AND
CONVECTION FASTER THEN HIGH BUST POTENTIAL REMAINS.
EXPECT MAIN AXIS OF CONVECTION TO BE EAST OF THE MOUNTAINS THIS
EVENING AND MAY TAKE SOME TIME TO EXIT THE PIEDMONT AS ANOTHER WEAK
IMPULSE RIDES UP THE FRONT. THINK SEVERE POTENTIAL LIMITED BEHIND
THE INIT WAVE OF STORMS BUT LINGERING HEAVY RAIN THREAT COULD
PERSIST WHILE SHOWERS BECOME WIDELY SCATTERED OR END BEHIND THE
BOUNDARY OVER THE MOUNTAINS OVERNIGHT. THEREFORE DID DECREASE POPS
A BIT FASTER WEST THINKING CONVECTION WILL HELP TAKE DEEP MOISTURE
TO THE EAST LATE...BUT LIKELY STILL LOTS OF CLOUDS AS THE UPPER
FLOW REMAINS SW AND PARALLEL TO THE SFC FRONT. MAIN PUSH OF 85H
COOL ADVECTION WILL STILL BE WEST OF THE BLUE RIDGE LATE TONIGHT
SO KEEPING TEMPS WARMER OUT EAST AND NOT QUITE AS COOL MOUNTAINS
PER CLOUD COVER. OTRW RANGE OF LOWS FROM AROUND 60 FAR WEST TO
65-70 SE LOOKS BEST.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 300 AM EDT FRIDAY...
SHORTWAVE PIVOTS ACROSS THE CENTRAL APPALACHIANS SATURDAY AFTERNOON.
THIS WILL KEEP THE THREAT OF SHOWERS AND ISOLATED THUNDERSTORMS
GOING IN THE EAST WITH COOL POOL ALOFT. 8H TEMPS COOL TO +14C...SO
WITH SOME CLOUD COVER FROM THE COLDER AIR ALOFT...EXPECT HIGHS
CLOSE TO THE ADJMETBC WITH READINGS FROM THE MID 70S IN THE
MOUNTAINS TO THE MID 80S IN THE SOUTHEAST.
DRIER AIR WILL FINALLY WORKS IN FROM THE NORTHWEST SATURDAY NIGHT
INTO SUNDAY WITH DEWPOINTS DROPPING INTO THE UPPER 40S/LOWER 50S IN
THE HIGHER ELEVATIONS WITH MID 50S VALLEYS. THE PIEDMONT COULD SEE
SOME 50S DEWPOINTS BUT HARD TO DISPLACE THE HUMID AIRMASS ACROSS THE
CAROLINAS AS THE FLOW ALOFT STAYS WSW. PLAYED LOW TEMPERATURES
SATURDAY NIGHT FROM THE LOWER 50S IN THE MOUNTAINS TO THE LOWER 60S
IN THE EAST.
ON SUNDAY...TEMPERATURES MODERATE WITH WSW FLOW AND MORE SUNSHINE.
HEIGHTS/8H TEMPERATURES INCREASE AGAIN...HIGHS SUNDAY RETURNING TO
AROUND 80 DEGREES IN THE MOUNTAINS TO THE UPPER 80S IN THE
SOUTHEAST. LEANED TOWARDS THE ECMWFBC FOR SUNDAY NIGHT LOW
TEMPERATURES WITH VALUES FROM THE MID 50S IN THE WEST TO THE MID 60S
IN THE EAST.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
AS OF 400 PM EDT THURSDAY...
DRIER AIRMASS WILL BE DISPLACED DURING THIS PERIOD AS THE FRONT FROM
THE SHORT TERM PERIOD STALLS ACROSS THE CAROLINAS/TN VALLEY THEN
SHIFTS SLOWLY NORTH BY TUESDAY AS ANOTHER WAVE OF LOW PRESSURE
SHIFTS ACROSS IT FROM THE LOWER MISSOURI VALLEY INTO THE VA
TIDEWATER FROM MON-TUE. THIS FRONT WILL BE CLOSE ENOUGH THAT
SHOWER/TSRA CHANCES INCREASE AGAIN BY TUESDAY. ONCE THE
SHORTWAVE/ASSOCIATED SFC LOW PASS TUESDAY AFTERNOON...WEAK HIGH
PRESSURE WILL PUSH THE FRONT BACK SOUTH INTO THE GA/SC BY WEDNESDAY
AND THE AIRMASS DRIES OUT SOME...BUT THE UPPER TROUGH IS NOT AS DEEP
AS THIS WEEKENDS. OVERALL...THE TEMPS NEXT WEEK WILL AVERAGE
80S/LOWER 90S FOR HIGHS AND 60S FOR LOWS.
&&
.AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...
AS OF 200 PM EDT FRIDAY...
CEILINGS HAVE LIFTED BACK UP TO VFR THIS AFTERNOON...WITH THE
EXCEPTION OF MVFR CEILINGS STILL PERSISTING IN BLF. BROKEN LINES
OF SHOWERS AND THUNDERSTORMS ARE DEVELOPING OVER KENTUCKY AND
TENNESSEE...AND ARE EXPECTED TO CONTINUE MOVING EASTWARD ALONG THE
ADVANCING SURFACE FRONT. A FEW SHOWERS ARE ALSO POPPING UP OVER
WEST VIRGINIA AHEAD OF THE FRONT. THUS...THUNDERSTORMS WERE KEPT
IN ALL THE TAFS. THE TIMING OF THE CONVECTION HAS SLOWED DOWN
SEVERAL HOURS FROM THE PREVIOUS FORECAST. THE TIME RANGE BETWEEN
20Z AND 03Z NOW SEEMS MOST FAVORABLE FOR THUNDERSTORMS.
ONCE THE PRECIPITATION SUBSIDES TONIGHT...THE MOIST GROUND WILL
PROVIDE THE POTENTIAL FOR SOME MVFR FOG IN BLF AND BCB. LWB IS
MOST LIKELY TO DROP TO LIFR WHEN THE WINDS TURN CALM OVERNIGHT.
MEANWHILE...TOO MUCH LOW CLOUD COVER WILL IMPEDE FURTHER FOG
DEVELOPMENT TO THE EAST. BY SATURDAY MORNING...A DRIER AIR MASS
BEHIND THE FRONT WILL MOVE INTO THE AREA...AND PROMPT A RETURN TO
VFR CONDITIONS. HIGH PRESSURE WILL PROVIDE GOOD FLYING WEATHER
THROUGH THE REMAINDER OF THIS WEEKEND INTO EARLY NEXT WEEK.
ANOTHER DISTURBANCE WILL PROVIDE THE NEXT CHANCE OF ISOLATED
SHOWERS AND THUNDERSTORMS BY TUESDAY AND WEDNESDAY.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...PW
NEAR TERM...JH/PW
SHORT TERM...KK
LONG TERM...WP
AVIATION...PW