Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 12/05/15
AREA FORECAST DISCUSSION
NWS MIAMI FL
332 PM EST THU DEC 3 2015
.DISCUSSION...
STEADY STREAM OF HEAVY SHOWERS AND EMBEDDED THUNDERSTORMS
FROM CUBA INTO THE KEYS, HAVE HAD A DIFFICULT TIME HOLDING
TOGETHER INTO THE PENINSULA THIS AFTERNOON. DESPITE THIS NEAR TERM
MODELS, ESPECIALLY THE HRRR CONTINUE TO FORECAST THESE CLUSTERS
EVENTUALLY ENTERING SOUTH FLORIDA LATE THIS AFTERNOON. THE HRRR
HAS BEEN FAR TOO AGGRESSIVE THIS AFTERNOON, SO SKEPTICAL OF THIS
ARRIVAL TIME. ABUNDANT CLOUDS HAVE ALSO PREVENTED ANY DEVELOPMENT
DUE TO DAYTIME HEATING SO FAR. UNDER THIS REGIME, TYPICALLY
OFFSHORE HVY SHOWERS AND THUNDERSTORMS HAVE MUCH BETTER SUCCESS
CROSSING LAND DURING THE EVENING AND OVERNIGHT HOURS. HOWEVER,
STILL CAN`T RULE OUT DEVELOPMENT DURING THE DAYTIME HOURS WITH THE
EAST COAST SEABREEZE POTENTIALLY LEADING TO ENOUGH SURFACE
CONVERGENCE/LIFT FOR WET WEATHER ALONG THE EAST COAST METRO. THIS
SEEMS TO BE OCCURRING IN BROWARD/FLL/FXE ATTM AND PARTS OF
INTERIOR MIAMI-DADE.
OVERALL, SOME CHANGES IN THE MODELS. STRONGER WINDS FORECASTED
BY THE MODELS TO AFFECT ALL OF THE EAST COAST AND ATLANTIC
WATERS, NOW ONLY MAKE IT TO PALM BEACH COUNTY. THIS MAY INDICATE
THAT THE WEAKENING COLD FRONT MAY NOT MAKE IT AS FAR SOUTH AS
PREVIOUSLY THOUGHT. SURFACE HIGH PRESSURE IS CENTERED A LITTLE
FURTHER NORTH THROUGH THE MIDDLE ATLANTIC WHICH LEADS TO LESS OF A
PRESSURE GRADIENT ALONG EXTREME SOUTH FL. THUS THERE IS A
DEVELOPING TREND TOWARDS THE HEAVIEST RAINFALL OCCURRING OVER THE
NORTHERN HALF OF THE FORECAST AREA, AS HEAVIEST QPF FROM THE
GFS/ECMWF HAS SHIFTED NORTH. REGARDLESSS, CAN`T PUT MUCH STOCK IN
RUN TO RUN VARIANCES, SO THE HEAVY RAIN THREAT CONTINUES FOR ALL
OF SOUTH FLORIDA.
FOR TONIGHT AND THE FIRST HALF OF FRIDAY, ADDITIONAL FORCING
PROVIDED BY A FEW MIDLEVEL DISTURBANCES AND MORE FAVORABLE
ORIENTATION OF THE UPPER JET, MAY BE THE EXTRA BOOST NEEDED TO
SPARK DEVELOPMENT. WIND FIELD REMAINS FAVORABLE FOR TRAINING AND
BACKBUILDING, ALSO LLVL HELICITY IS FAVORABLE FOR STRONGER STORMS.
WITH THE LACK OF ACTIVITY THUS FAR THIS PM, WILL HOLD OFF ON A
FLOOD WATCH AND CONTINUE TO ASSESS LATER THIS PM. WITH THE SLOWER
PROGRESSION OF THE FRONT, THE GFS DOES INDICATE SOME HEAVIER RAIN
REMAINING ACROSS THE SOUTHERN CWA INTO SATURDAY MORNING, WHEREAS
THE ECMWF HAS BACKED OFF. BOTH MODELS INDICATE A MIDLEVEL
DISTURBANCE CROSSING THE FL STRAITS AND KEYS, CLIPPING EXTREME SE
FL AROUND 6Z SAT. TOUGH TO ASCERTAIN HOW MUCH QPF FROM BOTH MODELS
ARE BEING INFLUENCED BY CONVECTIVE FEEDBACK. STRONGER MIDLEVEL SW
FLOW DOES SEEM TO END FRIDAY EVENING, WHICH WOULD SEEM TO CUTOFF
THE TRANSPORT OF ANOMALOUS MOISTURE ACROSS THE REGION, ALTHOUGH
PWATS WILL STILL BE ELEVATED. BY SATURDAY PM WINDS BECOME EASTERLY
THROUGH H85 AND ONSHORE FLOW WILL BE RESPONSIBLE FOR SHOWERS ALONG
THE EAST COAST. A SIMILAR SETUP IS EXPECTED ON SUNDAY.
DIFFUSE BOUNDARY WAVERS OVER SOUTH FL THROUGH MONDAY. INTO
MIDWEEK, A STRONGER COLD FRONT MOVING THROUGH THE SOUTHEAST CONUS
MAY FINALLY SHOVE THE WEAK BOUNDARY SOUTH USHERING IN DRIER AIR
WITH DEWPOINTS FALLING INTO THE MIDDLE 50S ACROSS THE
INTERIOR/LAKE REGION. HOWEVER, THE GFS IS FASTER WITH THIS
PROGRESSION WHEREAS THE ECMWF LAGS, WITH A WETTER FORECAST FOR
WEDNESDAY. THE GFS IS ALSO MUCH COOLER BEHIND THIS FRONT THAN THE
ECMWF
&&
.MARINE...
NUMEROUS SHOWERS AND SOME STRONGER THUNDERSTORMS EXPECTED AS A
WEAK COLD FRONT STALLS INTO SATURDAY AM. LATEST GUIDANCE
INDICATES THAT SMALL CRAFT ADV LEVEL WINDS MAY ONLY MAKE TO THE
ATLANTIC WATERS OFF PALM BEACH COUNTY. WIND SPEEDS MAY STAY AROUND
10 KTS FARTHER SOUTH. WAVE HEIGHTS ALONG THE GULF STREAM THOUGH
ARE STILL EXPECTED TO BE 7 FT AND ABOVE, HIGHEST OFFSHORE PALM
BEACH COUNTY. A WEAK TO MODERATE SWELL WILL ROLL DOWN THE EAST
COAST SAT AND SAT NIGHT. WAVES SUBSIDE SUNDAY NIGHT.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 70 78 74 80 / 90 90 60 70
FORT LAUDERDALE 69 78 69 79 / 90 80 70 70
MIAMI 71 80 71 81 / 80 80 70 70
NAPLES 67 77 68 82 / 100 80 40 30
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
SHORT TERM...21/KM
LONG TERM....21/KM
AREA FORECAST DISCUSSION
National Weather Service Lincoln IL
857 PM CST FRI DEC 4 2015
.UPDATE...
ISSUED AT 857 PM CST FRI DEC 4 2015
Have updated the forecast couple of times already this evening for
dense fog advisory and fog/low cigs advecting westward. Expecting
this to continue tonight and overnight so have already made
adjustments with the clouds and fog grids and think current
forecast is looking good. So no update planned at this time.
&&
.SHORT TERM...(Tonight)
ISSUED AT 300 PM CST FRI DEC 4 2015
High pressure is building into the Midwest this evening and is
expected to continue through the overnight. However, increased RH
trapped in the low levels from last nights fog has not mixed out
today, and this afternoons dewpoints are increasing across Central
Illinois. As the last of the fog bank erodes in the eastern half of
the state, sun is on its way down and the temps are going to start
cooling quickly with no clouds to trap in the warmer temps.
Effective radiational cooling and light winds under the ridge will
result in the airmass over ILX to become saturated quickly near the
surface. Have gone with a persistence forecast for fog tonight.
Areas in the west may see patchier fog, if that, with the winds
staying up a bit as the ridge axis slips to the east. Have gone
ahead and mentioned freezing fog again tonight with the temps
dropping below the freezing point before dawn.
.LONG TERM...(Saturday through Friday)
ISSUED AT 300 PM CST FRI DEC 4 2015
Signs are pointing to Saturday turning out much like today weather
wise. Areas of stratus & fog to start the day, that should
eventually burn off in most locales. High pressure will remain the
dominant player in our local weather, with associated light winds.
Forecast soundings show a persistent, very strong, near surface
inversion. Much like today, this should result in the shallow
stratus/fog lingering longer than might otherwise be expected, and
shallow vertical mixing keeping high temperatures cooler than would
be anticipated given the unusually mild temperatures aloft.
Mostly quiet weather should persist for much of the remainder of the
forecast period, although there will be some potential for
precipitation. However, the unseasonably mild condtions will help
keep any precipitation in liquid form. The first period of
opportunity for rainfall is expected to arrive late Sunday into
Sunday night. This threat will be driven by the short wave currently
coming ashore in California. Most of the guidance has this wave
amplifying and eventually developing into a small cutoff low by the
time it arrives. However, this system is expected to have little
moisture to work with and should result in minimal rainfall.
So, will keep PoPs in the Slight Chance category as a result.
Beyond Sunday night, the next chance for rainfall is not expected
until the second half of the week. Fast moving, quasi-zonal, upper-
level will shoot as least a couple short waves near the area by
Wednesday into Friday. However, there are differences in the
timing/track of these waves, which is not surprising given their
amplitude and fast flow pattern. This is resulting in several
periods with low PoPs. A much more significant wave, and greater
precipitation chances, is forecast to impact the area toward the
very end or just beyond the end of the current forecast period.
Hopefully model guidance will tighten up soon and we can get better
feeling for what is starting to look like an active weather pattern
to end next week.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
ISSUED AT 526 PM CST FRI DEC 4 2015
Skies are clear at PIA/SPI/BMI/DEC, but based on HRRR model and
satellite trends, believe dense fog and LIFR clouds will advect
over some of the other sites this evening. CMI is IFR now, but
expecting them to drop VLIFR this evening. DEC and BMI will also
drop to VLIFR before midnight as well. SPI and PIA will drop
slower and with some uncertainty with how far west the low clouds
and dense fog will reach will just have them fall to around 1sm
and then have a TEMPO group for 1/2sm FG. With ridge moving
slowly east during the day tomorrow, SPI and PIA will improve
quickly before noon. Other sites will be early afternoon once the
the southeasterly winds increase in speed to above 6-7kts.
&&
.ILX Watches/Warnings/Advisories...
Dense Fog Advisory until noon CST Saturday for ILZ029>031-037-
038-041>046-048-051>057-061>063-066>068-071>073.
&&
$$
UPDATE...Auten
SHORT TERM...HJS
LONG TERM...BAK
AVIATION...Auten
AREA FORECAST DISCUSSION
National Weather Service Lincoln IL
526 PM CST FRI DEC 4 2015
.SHORT TERM...(Tonight)
ISSUED AT 300 PM CST FRI DEC 4 2015
High pressure is building into the Midwest this evening and is
expected to continue through the overnight. However, increased RH
trapped in the low levels from last nights fog has not mixed out
today, and this afternoons dewpoints are increasing across Central
Illinois. As the last of the fog bank erodes in the eastern half of
the state, sun is on its way down and the temps are going to start
cooling quickly with no clouds to trap in the warmer temps.
Effective radiational cooling and light winds under the ridge will
result in the airmass over ILX to become saturated quickly near the
surface. Have gone with a persistence forecast for fog tonight.
Areas in the west may see patchier fog, if that, with the winds
staying up a bit as the ridge axis slips to the east. Have gone
ahead and mentioned freezing fog again tonight with the temps
dropping below the freezing point before dawn.
.LONG TERM...(Saturday through Friday)
ISSUED AT 300 PM CST FRI DEC 4 2015
Signs are pointing to Saturday turning out much like today weather
wise. Areas of stratus & fog to start the day, that should
eventually burn off in most locales. High pressure will remain the
dominant player in our local weather, with associated light winds.
Forecast soundings show a persistent, very strong, near surface
inversion. Much like today, this should result in the shallow
stratus/fog lingering longer than might otherwise be expected, and
shallow vertical mixing keeping high temperatures cooler than would
be anticipated given the unusually mild temperatures aloft.
Mostly quiet weather should persist for much of the remainder of the
forecast period, although there will be some potential for
precipitation. However, the unseasonably mild condtions will help
keep any precipitation in liquid form. The first period of
opportunity for rainfall is expected to arrive late Sunday into
Sunday night. This threat will be driven by the short wave currently
coming ashore in California. Most of the guidance has this wave
amplifying and eventually developing into a small cutoff low by the
time it arrives. However, this system is expected to have little
moisture to work with and should result in minimal rainfall.
So, will keep PoPs in the Slight Chance category as a result.
Beyond Sunday night, the next chance for rainfall is not expected
until the second half of the week. Fast moving, quasi-zonal, upper-
level will shoot as least a couple short waves near the area by
Wednesday into Friday. However, there are differences in the
timing/track of these waves, which is not surprising given their
amplitude and fast flow pattern. This is resulting in several
periods with low PoPs. A much more significant wave, and greater
precipitation chances, is forecast to impact the area toward the
very end or just beyond the end of the current forecast period.
Hopefully model guidance will tighten up soon and we can get better
feeling for what is starting to look like an active weather pattern
to end next week.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
ISSUED AT 526 PM CST FRI DEC 4 2015
Skies are clear at PIA/SPI/BMI/DEC, but based on HRRR model and
satellite trends, believe dense fog and LIFR clouds will advect
over some of the other sites this evening. CMI is IFR now, but
expecting them to drop VLIFR this evening. DEC and BMI will also
drop to VLIFR before midnight as well. SPI and PIA will drop
slower and with some uncertainty with how far west the low clouds
and dense fog will reach will just have them fall to around 1sm
and then have a TEMPO group for 1/2sm FG. With ridge moving
slowly east during the day tomorrow, SPI and PIA will improve
quickly before noon. Other sites will be early afternoon once the
the southeasterly winds increase in speed to above 6-7kts.
&&
.ILX Watches/Warnings/Advisories...
NONE.
&&
$$
SHORT TERM...HJS
LONG TERM...BAK
AVIATION...Auten
AREA FORECAST DISCUSSION
National Weather Service Lincoln IL
255 PM CST THU DEC 3 2015
.SHORT TERM...(Tonight)
ISSUED AT 255 PM CST THU DEC 3 2015
High pressure is building into the Midwest this evening and is
expected to continue through the overnight. However, residual
moisture trapped in the low levels is keeping stratus over Central
Illinois this afternoon. Mixing out this moisture has been limited
to the far west with dry air advecting in. This trend is expected
to continue and slowly erode the clouds west to east through the
evening/early tonight. With the loss of the clouds, sfc temps
should be able to drop fairly quickly, particularly with light and
variable winds under the ridge. Temps dropping before the bulk of
the dry air gets into the region could result in some fog tonight.
At this point, models are not clearing the clouds fast enough to
model the low level RH correctly. Expect some variability in the
fog development and longevity overnight, so keeping the patchy
wording.
&&
.LONG TERM...(Friday through Thursday)
ISSUED AT 255 PM CST THU DEC 3 2015
Generally quiet weather and at least slightly above normal
temperatures should prevail across central and southeast Illinois
over the next several days. A couple weak and moisture starved
disturbances will track across the forecast area during the period,
the first around Sunday night, and the second around Wednesday
night. Both disturbances will come off the Pacific in a quick moving
quasi-zonal flow, and there are (not surprisingly) some timing
differences. However, will not get too concerned with the timing
differences at this point given the low overall threat of
significant precipitation.
The quasi-zonal flow will help keep the real chilly air trapped well
north of the area through the period, helping keep temperatures
above normal. This scenario has been the case more often than not
over the past several weeks. However, did knock high temperatures
down a few degrees the next couple of days. While there should be
considerable sunshine, surface based WAA will not be significant.
Forecast soundings suggest a very strong, near surface based,
inversion will be in place. This inversion should preclude much in
the way of vertical mixing, and prohibit some of the warmer
temperatures aloft from working their way down.
&&
.AVIATION...(For the 18Z TAFS through 18Z Friday afternoon)
ISSUED AT 1132 AM CST THU DEC 3 2015
Complications for this forecast surround the clearing of the
MVFR/IFR stratus over Central Illinois. Concern this morning that
the cloud deck was not moving, however, the western edge has
started to erode somewhat. For now, will go with the more
optimistic drying out of the llvls in the models as there is some
consistency from RAP to NAM to GFS, and the HRRR the outlier, but
currently overestimating the cloud cover on sat imagery. For the
short term, keeping the stratus and the west/northwesterly winds
through sunset. Slow clearing from west to east overnight with low
confidence.
&&
.ILX Watches/Warnings/Advisories...
NONE.
&&
$$
SHORT TERM...HJS
LONG TERM...BAK
AVIATION...HJS
AREA FORECAST DISCUSSION
National Weather Service Lincoln IL
1148 AM CST THU DEC 3 2015
.UPDATE...
ISSUED AT 1048 AM CST THU DEC 3 2015
High pressure building into the region this morning is doing
little to prevent the low stratus to remain trapped at about 1000
ft for most of Central Illinois. Little change expected throughout
the day. Have adjusted the forecast here and there, enhancing
sky cover and adjusting the high temp for the day.
&&
.SHORT TERM...(Today)
ISSUED AT 322 AM CST THU DEC 3 2015
Main short-term forecast concern will be sky cover and its impact on
high temperatures today. 09z/3am IR satellite imagery shows a large
area of low clouds covering Wisconsin, the eastern half of Iowa,
into northern Missouri and western Illinois. The leading edge of
the clouds is currently along the Illinois River and pushing slowly
southeastward. Based on satellite timing tools...the clouds will
reach the I-55 corridor by 12z/6am, then will continue to spread
further east and south as the morning progresses. Models are not
handling the current cloud field particularly well, with the GFS
completely missing it and going with a mostly clear forecast today.
Even the NAM tends to aggressively scatter the clouds during the
morning, despite the presence of a strengthening subsidence
inversion. Meanwhile, the HRRR hangs on to the low clouds through
the entire day. Think the actual solution will be somewhere in
between...as upstream PIREPS from eastern Iowa reveal a cloud depth
of only around 1000 feet. Despite low sun angle, think shallow
cloud deck will gradually erode by mid to late afternoon. Overall
forecast will be mostly cloudy across much of the area, with
mostly sunny conditions prevailing along/south of I-70 where cloud
deck will never arrive. Even with some late afternoon sunshine,
temperatures will be held down quite a bit. Have therefore
undercut the MAV guidance by several degrees, with afternoon highs
remaining in the lower to middle 40s.
.LONG TERM...(Tonight through Wednesday)
ISSUED AT 322 AM CST THU DEC 3 2015
Quiet weather will prevail throughout the extended, with the only
weather feature of note passing through the region with little
fanfare Sunday into Monday. Before that system arrives, rising
upper heights and light southerly winds on the back side of strong
surface high pressure will yield an unseasonably warm weekend with
temperatures rising at least 10 degrees above normal for this time
of year. With abundant sunshine, highs on Saturday will climb into
the lower to middle 50s. MEX guidance even suggests some upper 50s
will be possible across the area. Temperatures will drop a few
degrees back into the upper 40s/lower 50s on Sunday as a short-wave
trough approaches from the west and spreads clouds into the area.
Models are now in fairly good agreement with the timing of this
system, with both the GFS and ECMWF bringing it through central
Illinois on Sunday. Due to an initially very dry airmass beneath
sprawling high pressure, the wave will have little moisture to
work with. The GFS tries to develop a few showers, but am quite
skeptical at this point. Will therefore only include slight
chance PoPs for showers across the western half of the CWA on
Sunday, then across the E/SE Sunday night. After that, a return
to warm and dry weather is anticipated through mid-week.
&&
.AVIATION...(For the 18Z TAFS through 18Z Friday afternoon)
ISSUED AT 1132 AM CST THU DEC 3 2015
Complications for this forecast surround the clearing of the
MVFR/IFR stratus over Central Illinois. Concern this morning that
the cloud deck was not moving, however, the western edge has
started to erode somewhat. For now, will go with the more
optimistic drying out of the llvls in the models as there is some
consistency from RAP to NAM to GFS, and the HRRR the outlier, but
currently overestimating the cloud cover on sat imagery. For the
short term, keeping the stratus and the west/northwesterly winds
through sunset. Slow clearing from west to east overnight with low
confidence.
&&
.ILX Watches/Warnings/Advisories...
NONE.
&&
$$
UPDATE...HJS
SHORT TERM...Barnes
LONG TERM...Barnes
AVIATION...HJS
AREA FORECAST DISCUSSION
National Weather Service Lincoln IL
1053 AM CST THU DEC 3 2015
.UPDATE...
ISSUED AT 1048 AM CST THU DEC 3 2015
High pressure building into the region this morning is doing
little to prevent the low stratus to remain trapped at about 1000
ft for most of Central Illinois. Little change expected throughoutthe
day. Have adjusted the forecast here and there, enhancing sky
cover and adjusting the high temp for the day.
&&
.SHORT TERM...(Today)
ISSUED AT 322 AM CST THU DEC 3 2015
Main short-term forecast concern will be sky cover and its impact on
high temperatures today. 09z/3am IR satellite imagery shows a large
area of low clouds covering Wisconsin, the eastern half of Iowa,
into northern Missouri and western Illinois. The leading edge of
the clouds is currently along the Illinois River and pushing slowly
southeastward. Based on satellite timing tools...the clouds will
reach the I-55 corridor by 12z/6am, then will continue to spread
further east and south as the morning progresses. Models are not
handling the current cloud field particularly well, with the GFS
completely missing it and going with a mostly clear forecast today.
Even the NAM tends to aggressively scatter the clouds during the
morning, despite the presence of a strengthening subsidence
inversion. Meanwhile, the HRRR hangs on to the low clouds through
the entire day. Think the actual solution will be somewhere in
between...as upstream PIREPS from eastern Iowa reveal a cloud depth
of only around 1000 feet. Despite low sun angle, think shallow
cloud deck will gradually erode by mid to late afternoon. Overall
forecast will be mostly cloudy across much of the area, with
mostly sunny conditions prevailing along/south of I-70 where cloud
deck will never arrive. Even with some late afternoon sunshine,
temperatures will be held down quite a bit. Have therefore
undercut the MAV guidance by several degrees, with afternoon highs
remaining in the lower to middle 40s.
.LONG TERM...(Tonight through Wednesday)
ISSUED AT 322 AM CST THU DEC 3 2015
Quiet weather will prevail throughout the extended, with the only
weather feature of note passing through the region with little
fanfare Sunday into Monday. Before that system arrives, rising
upper heights and light southerly winds on the back side of strong
surface high pressure will yield an unseasonably warm weekend with
temperatures rising at least 10 degrees above normal for this time
of year. With abundant sunshine, highs on Saturday will climb into
the lower to middle 50s. MEX guidance even suggests some upper 50s
will be possible across the area. Temperatures will drop a few
degrees back into the upper 40s/lower 50s on Sunday as a short-wave
trough approaches from the west and spreads clouds into the area.
Models are now in fairly good agreement with the timing of this
system, with both the GFS and ECMWF bringing it through central
Illinois on Sunday. Due to an initially very dry airmass beneath
sprawling high pressure, the wave will have little moisture to
work with. The GFS tries to develop a few showers, but am quite
skeptical at this point. Will therefore only include slight
chance PoPs for showers across the western half of the CWA on
Sunday, then across the E/SE Sunday night. After that, a return
to warm and dry weather is anticipated through mid-week.
&&
.AVIATION...(For the 12Z TAFS through 12Z Friday morning)
ISSUED AT 528 AM CST THU DEC 3 2015
An area of low cloud cover with low-end MVFR ceilings 1000-1500 ft
AGL will continue to over-spread the central IL terminals early
this morning...expected to reach all terminals by 13Z. Low cloud
cover is trapped beneath a temperature inversion aloft that will
cause this cloud cover to linger through much of the afternoon
before dissipating. Winds W-SW 4-8 kts until evening...becoming
light and variable.
&&
.ILX Watches/Warnings/Advisories...
NONE.
&&
$$
UPDATE...HJS
SHORT TERM...Barnes
LONG TERM...Barnes
AVIATION...Onton
AREA FORECAST DISCUSSION
National Weather Service Lincoln IL
528 AM CST THU DEC 3 2015
.SHORT TERM...(Today)
ISSUED AT 322 AM CST THU DEC 3 2015
Main short-term forecast concern will be sky cover and its impact on
high temperatures today. 09z/3am IR satellite imagery shows a large
area of low clouds covering Wisconsin, the eastern half of Iowa,
into northern Missouri and western Illinois. The leading edge of
the clouds is currently along the Illinois River and pushing slowly
southeastward. Based on satellite timing tools...the clouds will
reach the I-55 corridor by 12z/6am, then will continue to spread
further east and south as the morning progresses. Models are not
handling the current cloud field particularly well, with the GFS
completely missing it and going with a mostly clear forecast today.
Even the NAM tends to aggressively scatter the clouds during the
morning, despite the presence of a strengthening subsidence
inversion. Meanwhile, the HRRR hangs on to the low clouds through
the entire day. Think the actual solution will be somewhere in
between...as upstream PIREPS from eastern Iowa reveal a cloud depth
of only around 1000 feet. Despite low sun angle, think shallow
cloud deck will gradually erode by mid to late afternoon. Overall
forecast will be mostly cloudy across much of the area, with
mostly sunny conditions prevailing along/south of I-70 where cloud
deck will never arrive. Even with some late afternoon sunshine,
temperatures will be held down quite a bit. Have therefore
undercut the MAV guidance by several degrees, with afternoon highs
remaining in the lower to middle 40s.
.LONG TERM...(Tonight through Wednesday)
ISSUED AT 322 AM CST THU DEC 3 2015
Quiet weather will prevail throughout the extended, with the only
weather feature of note passing through the region with little
fanfare Sunday into Monday. Before that system arrives, rising
upper heights and light southerly winds on the back side of strong
surface high pressure will yield an unseasonably warm weekend with
temperatures rising at least 10 degrees above normal for this time
of year. With abundant sunshine, highs on Saturday will climb into
the lower to middle 50s. MEX guidance even suggests some upper 50s
will be possible across the area. Temperatures will drop a few
degrees back into the upper 40s/lower 50s on Sunday as a short-wave
trough approaches from the west and spreads clouds into the area.
Models are now in fairly good agreement with the timing of this
system, with both the GFS and ECMWF bringing it through central
Illinois on Sunday. Due to an initially very dry airmass beneath
sprawling high pressure, the wave will have little moisture to
work with. The GFS tries to develop a few showers, but am quite
skeptical at this point. Will therefore only include slight
chance PoPs for showers across the western half of the CWA on
Sunday, then across the E/SE Sunday night. After that, a return
to warm and dry weather is anticipated through mid-week.
&&
.AVIATION...(For the 12Z TAFS through 12Z Friday morning)
ISSUED AT 528 AM CST THU DEC 3 2015
An area of low cloud cover with low-end MVFR ceilings 1000-1500 ft
AGL will continue to over-spread the central IL terminals early
this morning...expected to reach all terminals by 13Z. Low cloud
cover is trapped beneath a temperature inversion aloft that will
cause this cloud cover to linger through much of the afternoon
before dissipating. Winds W-SW 4-8 kts until evening...becoming
light and variable.
&&
.ILX Watches/Warnings/Advisories...
NONE.
&&
$$
SHORT TERM...Barnes
LONG TERM...Barnes
AVIATION...Onton
AREA FORECAST DISCUSSION
National Weather Service Lincoln IL
322 AM CST THU DEC 3 2015
.SHORT TERM...(Today)
ISSUED AT 322 AM CST THU DEC 3 2015
Main short-term forecast concern will be sky cover and its impact on
high temperatures today. 09z/3am IR satellite imagery shows a large
area of low clouds covering Wisconsin, the eastern half of Iowa,
into northern Missouri and western Illinois. The leading edge of
the clouds is currently along the Illinois River and pushing slowly
southeastward. Based on satellite timing tools...the clouds will
reach the I-55 corridor by 12z/6am, then will continue to spread
further east and south as the morning progresses. Models are not
handling the current cloud field particularly well, with the GFS
completely missing it and going with a mostly clear forecast today.
Even the NAM tends to aggressively scatter the clouds during the
morning, despite the presence of a strengthening subsidence
inversion. Meanwhile, the HRRR hangs on to the low clouds through
the entire day. Think the actual solution will be somewhere in
between...as upstream PIREPS from eastern Iowa reveal a cloud depth
of only around 1000 feet. Despite low sun angle, think shallow
cloud deck will gradually erode by mid to late afternoon. Overall
forecast will be mostly cloudy across much of the area, with
mostly sunny conditions prevailing along/south of I-70 where cloud
deck will never arrive. Even with some late afternoon sunshine,
temperatures will be held down quite a bit. Have therefore
undercut the MAV guidance by several degrees, with afternoon highs
remaining in the lower to middle 40s.
&&
.LONG TERM...(Tonight through Wednesday)
ISSUED AT 322 AM CST THU DEC 3 2015
Quiet weather will prevail throughout the extended, with the only
weather feature of note passing through the region with little
fanfare Sunday into Monday. Before that system arrives, rising
upper heights and light southerly winds on the back side of strong
surface high pressure will yield an unseasonably warm weekend with
temperatures rising at least 10 degrees above normal for this time
of year. With abundant sunshine, highs on Saturday will climb into
the lower to middle 50s. MEX guidance even suggests some upper 50s
will be possible across the area. Temperatures will drop a few
degrees back into the upper 40s/lower 50s on Sunday as a short-wave
trough approaches from the west and spreads clouds into the area.
Models are now in fairly good agreement with the timing of this
system, with both the GFS and ECMWF bringing it through central
Illinois on Sunday. Due to an initially very dry airmass beneath
sprawling high pressure, the wave will have little moisture to
work with. The GFS tries to develop a few showers, but am quite
skeptical at this point. Will therefore only include slight
chance PoPs for showers across the western half of the CWA on
Sunday, then across the E/SE Sunday night. After that, a return
to warm and dry weather is anticipated through mid-week.
&&
.AVIATION...(For the 06Z TAFS through 06Z Thursday night)
ISSUED AT 1146 PM CST WED DEC 2 2015
Skies will be clear at all sites to start the TAF forecast.
However, as seen on satellite, an area of MVFR clouds is moving in
from the north and west. Believe, based on satellite trends and
HRRR forecast, that these clouds will advect over the sites
beginning at 09z at PIA and then move eastward, reaching CMI at
13z. With this low level moisture trapped beneath the strong
inversion of the high pressure area moving into the area
overnight, thinking is that the clouds will remain over the area
through the day and into the afternoon. Low sun angle will not
help either. Based on positioning of ridge, once that arrives into
the area, the clearing will begin. So have scattering of the
clouds beginning at PIA/DEC/SPI at 23z and then CMI/BMI at 00z.
Then have clearing of the skies about 3-4 hrs later. Winds will
remain light through the period, but begin out of the west to
northwest and then become more southeast or light and variable
during the evening hours.
&&
.ILX Watches/Warnings/Advisories...
NONE.
&&
$$
SHORT TERM...Barnes
LONG TERM...Barnes
AVIATION...Auten
AREA FORECAST DISCUSSION
National Weather Service Lincoln IL
1146 PM CST WED DEC 2 2015
.UPDATE...
ISSUED AT 900 PM CST WED DEC 2 2015
Have updated once already to reflect pcpn trends. Will be needing
another update to finish pcpn in the southeast and then try to
reflect the correct trend in the cloud cover remainder of the
night. This will be a challenge given the clear skies in the west,
the partly to mostly cloudy skies in the east, and then the
possible trend of more clouds moving into the west from IA/MO
later tonight. Satellite trends and new model data are being
monitored to see how much arrives and when. Another issue is
possible light fog overnight in the clear areas. HiRes models
indicate no fog issues overnight while Bufkit data shows some. For
now will leave out of gridded forecast. Update will be out
shortly.
&&
.SHORT TERM...(Tonight)
ISSUED AT 255 PM CST WED DEC 2 2015
Our large upper low was located near Chicago at mid afternoon. Last
of the surface boundaries rotating around the low extended from
about Rantoul to Taylorville on the most recent observations, with
the snow quickly tapering off west of it. Most accumulations have
been minor as temperatures remained above freezing, but some
localized reports around an inch were received mainly along and
north of I-74. Most of this precipitation should be out of the
forecast area by 6 pm, but will carry some low PoP`s near the
Indiana border until about mid evening.
Clearing trends behind the low will be a bit tricky. Large area of
clearing was dropping southward across Iowa with some breaks in west
central and northwest Illinois. However, clouds were still more
extensive across Wisconsin. NAM humidity plots quickly scour this
out over our area by mid evening, but the RAP is much slower with a
more persistent inversion around 2500 feet. Followed a more slow
trend with the sky grids for the cloud breakup, with skies partly
cloudy by midnight.
.LONG TERM...(Thursday through Wednesday)
ISSUED AT 255 PM CST WED DEC 2 2015
The upper low will depart well to the east of Illinois on Thursday,
as ridging builds into the Midwest. Surface high pressure and much
drier air will provide quiet weather for the remainder of the week
and first half of the weekend. Clouds will clear out on Thursday,
with increasing sunshine and southerly winds fueling a warming
trend through Saturday. Highs on Thursday will reach the low to
mid 40s, but temps will climb into the low 50s by Saturday.
A relatively zonal flow will continue into next week, but there
remains differences in timing of the next wave coming out of the
Plains. The ECMWF remains progressive with the next low, bringing it
into IL on Sunday and east of IL by Monday afternoon. The GFS and
Canadian show a slower solution, with somewhat of a cut-off period
for the upper low before it passes by to the south of Illinois late
Monday and Monday night. The forecast for Sunday through Monday
night was left relatively dry, with only slight chance PoPs south of
I-70 on Sunday night, and south of our counties south of highway 50
on Monday. Any precipitation should fall as rain, with the
temperatures remaining at or above normal during that time.
Another trough of low pressure could approach for Wednesday, per the
GFS, but the ECMWF keeps that system north of IL. The overall theme
looks to be for temps at or above normal, with lows in the low to
mid 30s and highs in the upper 40s to around 50 from Monday to
Wednesday next week, along with minimal precipitation.
&&
.AVIATION...(For the 06Z TAFS through 06Z Thursday night)
ISSUED AT 1146 PM CST WED DEC 2 2015
Skies will be clear at all sites to start the TAF forecast.
However, as seen on satellite, an area of MVFR clouds is moving in
from the north and west. Believe, based on satellite trends and
HRRR forecast, that these clouds will advect over the sites
beginning at 09z at PIA and then move eastward, reaching CMI at
13z. With this low level moisture trapped beneath the strong
inversion of the high pressure area moving into the area
overnight, thinking is that the clouds will remain over the area
through the day and into the afternoon. Low sun angle will not
help either. Based on positioning of ridge, once that arrives into
the area, the clearing will begin. So have scattering of the
clouds beginning at PIA/DEC/SPI at 23z and then CMI/BMI at 00z.
Then have clearing of the skies about 3-4 hrs later. Winds will
remain light through the period, but begin out of the west to
northwest and then become more southeast or light and variable
during the evening hours.
&&
.ILX Watches/Warnings/Advisories...
NONE.
&&
$$
UPDATE...Auten
SHORT TERM...Geelhart
LONG TERM...Shimon
AVIATION...Auten
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
537 PM EST THU DEC 3 2015
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 310 PM EST THU DEC 3 2015
DRY AND WARMER WEATHER WILL OCCUR THROUGH THE WEEKEND AS HIGH PRESSURE
OVER THE MIDDLE MISSISSIPPI VALLEY MOVES EAST ACROSS THE OHIO VALLEY
LATE TONIGHT AND FRIDAY AND TO SOUTHERN NEW ENGLAND OVER THE WEEKEND.
AN UPPER TROUGH WILL MOVE OUR WAY SUNDAY NIGHT AND MONDAY. BUT AT THE
MOMENT MODELS INDICATE MORE CLOUDS...BUT ONLY SLIGHT CHANCE OF SHOWERS
SOUTH AROUND SUNDAY NIGHT. SLIGHTLY WARMER AND DRY WEATHER WILL OCCUR
NEXT WEEK AS HIGH PRESSURE BUILDS ALONG THE ATLANTIC COAST.
&&
.NEAR TERM /TONIGHT/...
ISSUED AT 310 PM EST THU DEC 3 2015
SATELLITE INDICATES A LARGE AREA OF STRATUS OVER NORTH AND CENTRAL
SECTIONS...WHILE MOSTLY SUNNY SKIES HAVE CONTINUED ACROSS OUR SOUTH.
THE STATUS HAS BEEN CLEARING OVER WESTERN ILLINOIS....WHILE IT HAS
INCREASED A LITTLE ACROSS INDIANA.
EXPECT SOME CLEARING ACROSS ILLINOIS NEXT SEVERAL HOURS. HOWEVER RUC AND
NAM MODEL INDICATES POSSIBLE REDEVELOPMENT OF STRATUS AND FOG OVER
NORTH AND CENTRAL SECTIONS LATER TONIGHT. FOR NOW WILL KEEP SOME STRATUS
OVER NORTH AND CENTRAL SECTIONS OVERNIGHT...WHICH WOULD MINIMIZE THE
THREAT OF FOG. EVEN IF CLOUDS CLEAR...MODELS INDICATE SOME LOW LEVEL
SHEAR WHICH WOULD FAVOR STRATUS OVER FOG. SO FOR NOW WILL LEAVE OUT MENTION
OF FOG AS PARAMETERS ARE VERY IFFY. OVERNIGHT LOWS WILL BE IN THE MIDDLE
TO UPPER 20S WHICH IS CLOSE TO A MOS BLEND.
&&
.SHORT TERM /FRIDAY THROUGH SUNDAY/...
ISSUED AT 310 PM EST THU DEC 3 2015
DRY AND WARMER WEATHER WILL OCCUR THIS WEEKEND AS HIGH PRESSURE
MOVES ON TO THE EAST AND MODELS BUILD AN UPPER RIDGE OVER THE
EASTERN U.S. MODEL SOUNDINGS INDICATE MOSTLY CLEAR SKIES THROUGH
SATURDAY NIGHT AND THEN INCREASING CLOUDS SUNDAY AS AN UPPER TROUGH
MOVES OUR WAY.
MOST MODELS KEEP US DRY THROUGH SUNDAY AFTERNOON...WHILE THE EURO
INDICATES TRACE PRECIP AMOUNTS WEST AND SOUTH LATE SUNDAY. WILL GO
WITH CONSENSUS AND KEEP EVERYTHING DRY THROUGH SUNDAY. HIGHS WILL
BE IN THE UPPER 40S TO LOWER 50S FRIDAY AND SUNDAY AND IN THE LOWER
TO MIDDLE 50S SATURDAY. LOWS WILL BE IN THE UPPER 20S TO AROUND 30
FRIDAY NIGHT AND IN THE LOWER 30S SATURDAY NIGHT. WENT SLIGHTLY ABOVE
A MOS BLEND ON HIGHS WITH SOME SUN AND WARM ADVECTION. OTHERWISE...STAYED
CLOSE TO A MOS BLEND ON LOWS.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
ISSUED AT 240 PM EST THU DEC 3 2015
ENSEMBLES BRING AN UPPER WAVE ACROSS THE AREA SUNDAY NIGHT AS A WEAK
SURFACE SYSTEM SLIDES EAST ACROSS THE TENNESSEE VALLEY. MOISTURE
WILL BE LIMITED...HOWEVER THE FORCING IS ENOUGH TO CONTINUE TO CARRY
WEAK CHANCES OF RAIN SHOWERS ACROSS THE SOUTHERN TIER.
WEAK RIDGING WILL PREVAIL THROUGHOUT MOST OF THE EXTENDED WITH DRY
CONDITIONS AND WARMER THAN NORMAL TEMPERATURES THROUGHOUT NEXT
WEEK.
&&
.AVIATION /DISCUSSION FOR THE 040000Z TAFS/...
ISSUED AT 537 PM EST THU DEC 3 2015
EXTENSIVE AREA OF MVFR CEILINGS 012-020 COVERS MOST OF NORTHERN AND
CENTRAL INDIANA...AFFECTING THE KLAF/KHUF/KIND TERMINALS AT THIS TIME.
SATELLITE LOOPS INDICATE THE SOUTHERN EDGE HAS MOVED LITTLE OVER THE PAST
COUPLE OF HOURS...HOWEVER THE WESTERN EDGE HAS BEEN ERODING OVER ILLINOIS.
GIVEN THE LOW LEVEL FLOW IS EXPECTED TO BACK AROUND TO THE WEST SOUTHWEST
WITH TIME...EXPECT THESE CEILINGS TO GRADUALLY ERODE FROM THE WEST...BUT IT
PROBABLY WON/T BE UNTIL LATE TONIGHT BEFORE THIS HAPPENS.
ONCE THE LOW CLOUDS CLEAR OUT...LINGERING LOW LEVEL MOISTURE WILL LEAD TO
SOME FOG FORMATION...ALTHOUGH CONFIDENCE ON VISIBILITY FORECASTS IS LOW
DUE TO QUESTIONS REVOLVING ON HOW FAST LOW CLOUDS CLEAR OUT. AT THIS TIME...IT
APPEARS THE BEST CHANCES FOR IFR VISIBILITY RESTRICTIONS WILL BE IN THE
KHUF/KBMG AREAS...WHICH ARE CLOSER TO THE CLEARING LINE AND LIGHTEST WINDS.
SURFACE WINDS AT OR BELOW 7 KTS TONIGHT.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...JH
NEAR TERM...JH
SHORT TERM...JH
LONG TERM...SMF
AVIATION...JAS
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
324 PM EST THU DEC 3 2015
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 310 PM EST THU DEC 3 2015
DRY AND WARMER WEATHER WILL OCCUR THROUGH THE WEEKEND AS HIGH PRESSURE
OVER THE MIDDLE MISSISSIPPI VALLEY MOVES EAST ACROSS THE OHIO VALLEY
LATE TONIGHT AND FRIDAY AND TO SOUTHERN NEW ENGLAND OVER THE WEEKEND.
AN UPPER TROUGH WILL MOVE OUR WAY SUNDAY NIGHT AND MONDAY. BUT AT THE
MOMENT MODELS INDICATE MORE CLOUDS...BUT ONLY SLIGHT CHANCE OF SHOWERS
SOUTH AROUND SUNDAY NIGHT. SLIGHTLY WARMER AND DRY WEATHER WILL OCCUR
NEXT WEEK AS HIGH PRESSURE BUILDS ALONG THE ATLANTIC COAST.
&&
.NEAR TERM /TONIGHT/...
ISSUED AT 310 PM EST THU DEC 3 2015
SATELLITE INDICATES A LARGE AREA OF STRATUS OVER NORTH AND CENTRAL
SECTIONS...WHILE MOSTLY SUNNY SKIES HAVE CONTINUED ACROSS OUR SOUTH.
THE STATUS HAS BEEN CLEARING OVER WESTERN ILLINOIS....WHILE IT HAS
INCREASED A LITTLE ACROSS INDIANA.
EXPECT SOME CLEARING ACROSS ILLINOIS NEXT SEVERAL HOURS. HOWEVER RUC AND
NAM MODEL INDICATES POSSIBLE REDEVELOPMENT OF STRATUS AND FOG OVER
NORTH AND CENTRAL SECTIONS LATER TONIGHT. FOR NOW WILL KEEP SOME STRATUS
OVER NORTH AND CENTRAL SECTIONS OVERNIGHT...WHICH WOULD MINIMIZE THE
THREAT OF FOG. EVEN IF CLOUDS CLEAR...MODELS INDICATE SOME LOW LEVEL
SHEAR WHICH WOULD FAVOR STRATUS OVER FOG. SO FOR NOW WILL LEAVE OUT MENTION
OF FOG AS PARAMETERS ARE VERY IFFY. OVERNIGHT LOWS WILL BE IN THE MIDDLE
TO UPPER 20S WHICH IS CLOSE TO A MOS BLEND.
&&
.SHORT TERM /FRIDAY THROUGH SUNDAY/...
ISSUED AT 310 PM EST THU DEC 3 2015
DRY AND WARMER WEATHER WILL OCCUR THIS WEEKEND AS HIGH PRESSURE
MOVES ON TO THE EAST AND MODELS BUILD AN UPPER RIDGE OVER THE
EASTERN U.S. MODEL SOUNDINGS INDICATE MOSTLY CLEAR SKIES THROUGH
SATURDAY NIGHT AND THEN INCREASING CLOUDS SUNDAY AS AN UPPER TROUGH
MOVES OUR WAY.
MOST MODELS KEEP US DRY THROUGH SUNDAY AFTERNOON...WHILE THE EURO
INDICATES TRACE PRECIP AMOUNTS WEST AND SOUTH LATE SUNDAY. WILL GO
WITH CONSENSUS AND KEEP EVERYTHING DRY THROUGH SUNDAY. HIGHS WILL
BE IN THE UPPER 40S TO LOWER 50S FRIDAY AND SUNDAY AND IN THE LOWER
TO MIDDLE 50S SATURDAY. LOWS WILL BE IN THE UPPER 20S TO AROUND 30
FRIDAY NIGHT AND IN THE LOWER 30S SATURDAY NIGHT. WENT SLIGHTLY ABOVE
A MOS BLEND ON HIGHS WITH SOME SUN AND WARM ADVECTION. OTHERWISE...STAYED
CLOSE TO A MOS BLEND ON LOWS.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
ISSUED AT 240 PM EST THU DEC 3 2015
ENSEMBLES BRING AN UPPER WAVE ACROSS THE AREA SUNDAY NIGHT AS A WEAK
SURFACE SYSTEM SLIDES EAST ACROSS THE TENNESSEE VALLEY. MOISTURE
WILL BE LIMITED...HOWEVER THE FORCING IS ENOUGH TO CONTINUE TO CARRY
WEAK CHANCES OF RAIN SHOWERS ACROSS THE SOUTHERN TIER.
WEAK RIDGING WILL PREVAIL THROUGHOUT MOST OF THE EXTENDED WITH DRY
CONDITIONS AND WARMER THAN NORMAL TEMPERATURES THROUGHOUT NEXT
WEEK.
&&
.AVIATION /DISCUSSION FOR THE 03/21Z TAF UPDATE/...
ISSUED AT 324 PM EST THU DEC 3 2015
MINOR ADJUSTMENTS TO TAFS BASED ON LATEST OBS. PREVIOUS DISCUSSION
FOLLOWS.
ISSUED AT 1223 PM EST THU DEC 3 2015
THE MVFR STRATUS DECK WHICH WAS OVER CENTRAL ILLINOIS EARLIER THIS
MORNING HAS DRIFTED TO THE SOUTHEAST AND IS NOW COVERING A GOOD
PORTION OF CENTRAL INDIANA AND ONLY INCREASING IN COVERAGE. ALL
THE CEILINGS UPSTREAM AND AT SITES SUCH AS LAF/HUF AND EVEN MOST
RECENTLY IND...BKN-OVC015 IS BEING REPORTED SO WENT WITH THIS AS
THE PREVAILING CLOUD CATEGORY FOR THE REST OF THIS AFTERNOON.
QUESTION THEN TURNS TO HOW MUCH...IF ANY? WILL THIS CLOUD DECK
THIN OUT BY THIS EVENING. GUIDANCE IS VIRTUALLY LITTLE HELP AS IT
HAS NOT CAUGHT ON TO THIS DECK EVEN MOVING INTO CENTRAL
INDIANA...SO HOPEFULLY THE NEXT MODEL RUN WILL BE MORE
REPRESENTATIVE OF THE CURRENT CONDITIONS.
WENT THE OPTIMISTIC ROUTE...GRADUALLY CLEARING SKIES BY THIS
EVENING AND THEN INTRODUCING MVFR VISIBILITIES (PER MAINLY THE
NAM MOS) CONSIDERING THE MOIST GROUND...CLEAR SKIES AND CALM WINDS
EXPECTED OVERNIGHT.
BUT THERE IS A CHANCE THIS STRATUS DECK MAY NOT BE GOING
ANYWHERE...WHICH MEAN ALL THE TERMINALS WILL STAY AT MVFR FOR THIS
EVENING AND THE OVERNIGHT. WILL CONTINUE TO MONITOR THE LATEST
TRENDS VIA VISIBLE SATELLITE IMAGERY FOR ANY BREAKS OR
THINNING...AND ALSO AWAIT THE LATEST NEAR TERM GUIDANCE.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...JH
NEAR TERM...JH
SHORT TERM...JH
LONG TERM...SMF
AVIATION...SMF/NIELD
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
310 PM EST THU DEC 3 2015
.UPDATE...
SYNOPSIS...NEAR TERM AND SHORT TERM SECTIONS HAVE BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 310 PM EST THU DEC 3 2015
DRY AND WARMER WEATHER WILL OCCUR THROUGH THE WEEKEND AS HIGH PRESSURE
OVER THE MIDDLE MISSISSIPPI VALLEY MOVES EAST ACROSS THE OHIO VALLEY
LATE TONIGHT AND FRIDAY AND TO SOUTHERN NEW ENGLAND OVER THE WEEKEND.
AN UPPER TROUGH WILL MOVE OUR WAY SUNDAY NIGHT AND MONDAY. BUT AT THE
MOMENT MODELS INDICATE MORE CLOUDS...BUT ONLY SLIGHT CHANCE OF SHOWERS
SOUTH AROUND SUNDAY NIGHT. SLIGHTLY WARMER AND DRY WEATHER WILL OCCUR
NEXT WEEK AS HIGH PRESSURE BUILDS ALONG THE ATLANTIC COAST.
&&
.NEAR TERM /TONIGHT/...
ISSUED AT 310 PM EST THU DEC 3 2015
SATELLITE INDICATES A LARGE AREA OF STRATUS OVER NORTH AND CENTRAL
SECTIONS...WHILE MOSTLY SUNNY SKIES HAVE CONTINUED ACROSS OUR SOUTH.
THE STATUS HAS BEEN CLEARING OVER WESTERN ILLINOIS....WHILE IT HAS
INCREASED A LITTLE ACROSS INDIANA.
EXPECT SOME CLEARING ACROSS ILLINOIS NEXT SEVERAL HOURS. HOWEVER RUC AND
NAM MODEL INDICATES POSSIBLE REDEVELOPMENT OF STRATUS AND FOG OVER
NORTH AND CENTRAL SECTIONS LATER TONIGHT. FOR NOW WILL KEEP SOME STRATUS
OVER NORTH AND CENTRAL SECTIONS OVERNIGHT...WHICH WOULD MINIMIZE THE
THREAT OF FOG. EVEN IF CLOUDS CLEAR...MODELS INDICATE SOME LOW LEVEL
SHEAR WHICH WOULD FAVOR STRATUS OVER FOG. SO FOR NOW WILL LEAVE OUT MENTION
OF FOG AS PARAMETERS ARE VERY IFFY. OVERNIGHT LOWS WILL BE IN THE MIDDLE
TO UPPER 20S WHICH IS CLOSE TO A MOS BLEND.
&&
.SHORT TERM /FRIDAY THROUGH SUNDAY/...
ISSUED AT 310 PM EST THU DEC 3 2015
DRY AND WARMER WEATHER WILL OCCUR THIS WEEKEND AS HIGH PRESSURE
MOVES ON TO THE EAST AND MODELS BUILD AN UPPER RIDGE OVER THE
EASTERN U.S. MODEL SOUNDINGS INDICATE MOSTLY CLEAR SKIES THROUGH
SATURDAY NIGHT AND THEN INCREASING CLOUDS SUNDAY AS AN UPPER TROUGH
MOVES OUR WAY.
MOST MODELS KEEP US DRY THROUGH SUNDAY AFTERNOON...WHILE THE EURO
INDICATES TRACE PRECIP AMOUNTS WEST AND SOUTH LATE SUNDAY. WILL GO
WITH CONSENSUS AND KEEP EVERYTHING DRY THROUGH SUNDAY. HIGHS WILL
BE IN THE UPPER 40S TO LOWER 50S FRIDAY AND SUNDAY AND IN THE LOWER
TO MIDDLE 50S SATURDAY. LOWS WILL BE IN THE UPPER 20S TO AROUND 30
FRIDAY NIGHT AND IN THE LOWER 30S SATURDAY NIGHT. WENT SLIGHTLY ABOVE
A MOS BLEND ON HIGHS WITH SOME SUN AND WARM ADVECTION. OTHERWISE...STAYED
CLOSE TO A MOS BLEND ON LOWS.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
ISSUED AT 240 PM EST THU DEC 3 2015
ENSEMBLES BRING AN UPPER WAVE ACROSS THE AREA SUNDAY NIGHT AS A WEAK
SURFACE SYSTEM SLIDES EAST ACROSS THE TENNESSEE VALLEY. MOISTURE
WILL BE LIMITED...HOWEVER THE FORCING IS ENOUGH TO CONTINUE TO CARRY
WEAK CHANCES OF RAIN SHOWERS ACROSS THE SOUTHERN TIER.
WEAK RIDGING WILL PREVAIL THROUGHOUT MOST OF THE EXTENDED WITH DRY
CONDITIONS AND WARMER THAN NORMAL TEMPERATURES THROUGHOUT NEXT
WEEK.
&&
.AVIATION /DISCUSSION FOR THE 031800Z TAF ISSUANCE/...
ISSUED AT 1223 PM EST THU DEC 3 2015
THE MVFR STRATUS DECK WHICH WAS OVER CENTRAL ILLINOIS EARLIER THIS
MORNING HAS DRIFTED TO THE SOUTHEAST AND IS NOW COVERING A GOOD
PORTION OF CENTRAL INDIANA AND ONLY INCREASING IN COVERAGE. ALL
THE CEILINGS UPSTREAM AND AT SITES SUCH AS LAF/HUF AND EVEN MOST
RECENTLY IND...BKN-OVC015 IS BEING REPORTED SO WENT WITH THIS AS
THE PREVAILING CLOUD CATEGORY FOR THE REST OF THIS AFTERNOON.
QUESTION THEN TURNS TO HOW MUCH...IF ANY? WILL THIS CLOUD DECK
THIN OUT BY THIS EVENING. GUIDANCE IS VIRTUALLY LITTLE HELP AS IT
HAS NOT CAUGHT ON TO THIS DECK EVEN MOVING INTO CENTRAL
INDIANA...SO HOPEFULLY THE NEXT MODEL RUN WILL BE MORE
REPRESENTATIVE OF THE CURRENT CONDITIONS.
WENT THE OPTIMISTIC ROUTE...GRADUALLY CLEARING SKIES BY THIS
EVENING AND THEN INTRODUCING MVFR VISIBILITIES (PER MAINLY THE
NAM MOS) CONSIDERING THE MOIST GROUND...CLEAR SKIES AND CALM WINDS
EXPECTED OVERNIGHT.
BUT THERE IS A CHANCE THIS STRATUS DECK MAY NOT BE GOING
ANYWHERE...WHICH MEAN ALL THE TERMINALS WILL STAY AT MVFR FOR THIS
EVENING AND THE OVERNIGHT. WILL CONTINUE TO MONITOR THE LATEST
TRENDS VIA VISIBLE SATELLITE IMAGERY FOR ANY BREAKS OR
THINNING...AND ALSO AWAIT THE LATEST NEAR TERM GUIDANCE.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...JH
NEAR TERM...JH
SHORT TERM...JH
LONG TERM...SMF
AVIATION...SMF
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
242 PM EST THU DEC 3 2015
.UPDATE...
THE LONG TERM SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 331 AM EST THU DEC 3 2015
HIGH PRESSURE WILL RESULT IN DRY CONDITIONS THROUGH THE WEEKEND
WITH A WEAK WARMING TREND. THE ONLY CHANCES FOR RAIN WILL BE
ACROSS THE SOUTHERN PORTIONS OF CENTRAL INDIANA ON SUNDAY NIGHT
WHEN A LOW PRESSURE SYSTEM PASSES THROUGH THE TENNESSEE VALLEY.
&&
.NEAR TERM /REST OF TODAY/...
ISSUED AT 1005 AM EST THU DEC 3 2015
SATELLITE INDICATES STRATUS WAS ACROSS OUR FAR NORTHEAST SECTIONS ALONG
AND EAST OF A ANDERSON TO NEW CASTLE LINE AND ALSO HAD SPREAD
INTO NORTHWEST SECTIONS WEST OF LAFAYETTE. RUC MODEL INDICATES
STRATUS WILL SPREAD SOUTH...WHILE THE NAM CLEAR IT OUT EVERYWHERE.
WILL GO WITH A COMPROMISE WITH A LITTLE MORE CLOUDS OVER NORTHWEST
AND NORTHEAST SECTIONS BUT OTHERWISE MOSTLY SUNNY CENTRAL AND
SOUTH.
HIGH PRESSURE OVER MISSOURI WILL MOVE TO SOUTHWEST INDIANA BY THIS EVENING.
CONCERNING TEMPERATURES...DROPPED THEM SLIGHTLY OVER NORTHWEST AND NORTHEAST
SECTIONS WITH MORE CLOUDS. OTHERWISE...LOWER 40S WILL BE THE RULE MOST OTHER
AREAS WITH MIDDLE 40S FAR SOUTHWEST.
&&
.SHORT TERM /TONIGHT THROUGH SATURDAY NIGHT/...
ISSUED AT 331 AM EST THU DEC 3 2015
CENTRAL INDIANA WILL REMAIN UNDER THE INFLUENCE OF HIGH PRESSURE
FOR THE ENTIRE SHORT TERM PERIOD. AS A RESULT...DRY CONDITIONS
WITH ABOVE NORMAL TEMPERATURES WILL BE THE TREND. DAYTIME HIGHS
WILL TOP OFF IN THE UPPER 40S/LOW 50S WITH SOME POSSIBLE MID 50S
ACROSS THE SOUTHERN COUNTIES ON SATURDAY. MEANWHILE...OVERNIGHT
LOWS WILL REMAIN STEADY IN THE UPPER 20S/LOW 30S. MAVMOS NUMBERS
LOOK REASONABLE FOR THIS PATTERN.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
ISSUED AT 240 PM EST THU DEC 3 2015
ENSEMBLES BRING AN UPPER WAVE ACROSS THE AREA SUNDAY NIGHT AS A WEAK
SURFACE SYSTEM SLIDES EAST ACROSS THE TENNESSEE VALLEY. MOISTURE
WILL BE LIMITED...HOWEVER THE FORCING IS ENOUGH TO CONTINUE TO CARRY
WEAK CHANCES OF RAIN SHOWERS ACROSS THE SOUTHERN TIER.
WEAK RIDGING WILL PREVAIL THROUGHOUT MOST OF THE EXTENDED WITH DRY
CONDITIONS AND WARMER THAN NORMAL TEMPERATURES THROUGHOUT NEXT
WEEK.
&&
.AVIATION /DISCUSSION FOR THE 031800Z TAF ISSUANCE/...
ISSUED AT 1223 PM EST THU DEC 3 2015
THE MVFR STRATUS DECK WHICH WAS OVER CENTRAL ILLINOIS EARLIER THIS
MORNING HAS DRIFTED TO THE SOUTHEAST AND IS NOW COVERING A GOOD
PORTION OF CENTRAL INDIANA AND ONLY INCREASING IN COVERAGE. ALL
THE CEILINGS UPSTREAM AND AT SITES SUCH AS LAF/HUF AND EVEN MOST
RECENTLY IND...BKN-OVC015 IS BEING REPORTED SO WENT WITH THIS AS
THE PREVAILING CLOUD CATEGORY FOR THE REST OF THIS AFTERNOON.
QUESTION THEN TURNS TO HOW MUCH...IF ANY? WILL THIS CLOUD DECK
THIN OUT BY THIS EVENING. GUIDANCE IS VIRTUALLY LITTLE HELP AS IT
HAS NOT CAUGHT ON TO THIS DECK EVEN MOVING INTO CENTRAL
INDIANA...SO HOPEFULLY THE NEXT MODEL RUN WILL BE MORE
REPRESENTATIVE OF THE CURRENT CONDITIONS.
WENT THE OPTIMISTIC ROUTE...GRADUALLY CLEARING SKIES BY THIS
EVENING AND THEN INTRODUCING MVFR VISIBILITIES (PER MAINLY THE
NAM MOS) CONSIDERING THE MOIST GROUND...CLEAR SKIES AND CALM WINDS
EXPECTED OVERNIGHT.
BUT THERE IS A CHANCE THIS STRATUS DECK MAY NOT BE GOING
ANYWHERE...WHICH MEAN ALL THE TERMINALS WILL STAY AT MVFR FOR THIS
EVENING AND THE OVERNIGHT. WILL CONTINUE TO MONITOR THE LATEST
TRENDS VIA VISIBLE SATELLITE IMAGERY FOR ANY BREAKS OR
THINNING...AND ALSO AWAIT THE LATEST NEAR TERM GUIDANCE.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...TDUD
NEAR TERM...JH
SHORT TERM...TDUD
LONG TERM....SMF
AVIATION...SMF
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1230 PM EST THU DEC 3 2015
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 331 AM EST THU DEC 3 2015
HIGH PRESSURE WILL RESULT IN DRY CONDITIONS THROUGH THE WEEKEND
WITH A WEAK WARMING TREND. THE ONLY CHANCES FOR RAIN WILL BE
ACROSS THE SOUTHERN PORTIONS OF CENTRAL INDIANA ON SUNDAY NIGHT
WHEN A LOW PRESSURE SYSTEM PASSES THROUGH THE TENNESSEE VALLEY.
&&
.NEAR TERM /REST OF TODAY/...
ISSUED AT 1005 AM EST THU DEC 3 2015
SATELLITE INDICATES STRATUS WAS ACROSS OUR FAR NORTHEAST SECTIONS ALONG
AND EAST OF A ANDERSON TO NEW CASTLE LINE AND ALSO HAD SPREAD
INTO NORTHWEST SECTIONS WEST OF LAFAYETTE. RUC MODEL INDICATES
STRATUS WILL SPREAD SOUTH...WHILE THE NAM CLEAR IT OUT EVERYWHERE.
WILL GO WITH A COMPROMISE WITH A LITTLE MORE CLOUDS OVER NORTHWEST
AND NORTHEAST SECTIONS BUT OTHERWISE MOSTLY SUNNY CENTRAL AND
SOUTH.
HIGH PRESSURE OVER MISSOURI WILL MOVE TO SOUTHWEST INDIANA BY THIS EVENING.
CONCERNING TEMPERATURES...DROPPED THEM SLIGHTLY OVER NORTHWEST AND NORTHEAST
SECTIONS WITH MORE CLOUDS. OTHERWISE...LOWER 40S WILL BE THE RULE MOST OTHER
AREAS WITH MIDDLE 40S FAR SOUTHWEST.
&&
.SHORT TERM /TONIGHT THROUGH SATURDAY NIGHT/...
ISSUED AT 331 AM EST THU DEC 3 2015
CENTRAL INDIANA WILL REMAIN UNDER THE INFLUENCE OF HIGH PRESSURE
FOR THE ENTIRE SHORT TERM PERIOD. AS A RESULT...DRY CONDITIONS
WITH ABOVE NORMAL TEMPERATURES WILL BE THE TREND. DAYTIME HIGHS
WILL TOP OFF IN THE UPPER 40S/LOW 50S WITH SOME POSSIBLE MID 50S
ACROSS THE SOUTHERN COUNTIES ON SATURDAY. MEANWHILE...OVERNIGHT
LOWS WILL REMAIN STEADY IN THE UPPER 20S/LOW 30S. MAVMOS NUMBERS
LOOK REASONABLE FOR THIS PATTERN.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY NIGHT/...
ISSUED AT 330 AM EST THU DEC 3 2015
MOSTLY DRY WEATHER AND SLIGHTLY ABOVE NORMAL TEMPERATURES ARE
EXPECTED LATE THIS WEEKEND THROUGH LATE NEXT WEEK COURTESY OF THE
MUCH TALKED ABOUT STRONG EL NINO.
THE 00Z ECMWF AND GFS BOTH BRING AN UPPER WAVE ACROSS THE AREA
SUNDAY NIGHT AS A WEAK SURFACE SYSTEM SLIDES EAST ACROSS THE
TENNESSEE VALLEY. ALTHOUGH THERE WILL NOT BE A LOT OF MOISTURE TO
WORK WITH...THE FORCING IS ENOUGH TO INCLUDE SMALL RAIN SHOWER
CHANCES ACROSS OUR SOUTHERN COUNTIES SUNDAY NIGHT. ANOTHER WEAKER
WAVE WILL MOVE THROUGH THE OHIO VALLEY LATE TUESDAY. HOWEVER...WITH
LESS FORCING AND LITTLE MOISTURE...WILL GO WITH A DRY FORECAST. ON
FINAL WAVE LOOKS TO MOVE THROUGH SOMEWHERE ACROSS THE GREAT LAKES OR
OHIO VALLEY WEDNESDAY NIGHT. HOWEVER...THE MODELS ARE WAY APART ON
TIMING AND STRENGTH AND BOTH SHOW LIMITED MOISTURE.
LOW LEVEL THERMAL AND SKY COVER PROGS ALONG WITH THE OVERALL
SYNOPTIC PATTERN LINE UP NICELY WITH THE REGIONAL BLEND REGARDING
TEMPERATURES. LOOK FOR AFTERNOON HIGHS IN THE MID 40S TO THE LOWER
50S AND LOWS IN THE 30S.
&&
AVIATION /DISCUSSION FOR THE 031800Z TAF ISSUANCE/...
ISSUED AT 1223 PM EST THU DEC 3 2015
THE MVFR STRATUS DECK WHICH WAS OVER CENTRAL ILLINOIS EARLIER THIS
MORNING HAS DRIFTED TO THE SOUTHEAST AND IS NOW COVERING A GOOD
PORTION OF CENTRAL INDIANA AND ONLY INCREASING IN COVERAGE. ALL
THE CEILINGS UPSTREAM AND AT SITES SUCH AS LAF/HUF AND EVEN MOST
RECENTLY IND...BKN-OVC015 IS BEING REPORTED SO WENT WITH THIS AS
THE PREVAILING CLOUD CATEGORY FOR THE REST OF THIS AFTERNOON.
QUESTION THEN TURNS TO HOW MUCH...IF ANY? WILL THIS CLOUD DECK
THIN OUT BY THIS EVENING. GUIDANCE IS VIRTUALLY LITTLE HELP AS IT
HAS NOT CAUGHT ON TO THIS DECK EVEN MOVING INTO CENTRAL
INDIANA...SO HOPEFULLY THE NEXT MODEL RUN WILL BE MORE
REPRESENTATIVE OF THE CURRENT CONDITIONS.
WENT THE OPTIMISTIC ROUTE...GRADUALLY CLEARING SKIES BY THIS
EVENING AND THEN INTRODUCING MVFR VISIBILITIES (PER MAINLY THE
NAM MOS) CONSIDERING THE MOIST GROUND...CLEAR SKIES AND CALM WINDS
EXPECTED OVERNIGHT.
BUT THERE IS A CHANCE THIS STRATUS DECK MAY NOT BE GOING
ANYWHERE...WHICH MEAN ALL THE TERMINALS WILL STAY AT MVFR FOR THIS
EVENING AND THE OVERNIGHT. WILL CONTINUE TO MONITOR THE LATEST
TRENDS VIA VISIBLE SATELLITE IMAGERY FOR ANY BREAKS OR
THINNING...AND ALSO AWAIT THE LATEST NEAR TERM GUIDANCE.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...TDUD
NEAR TERM...JH
SHORT TERM...TDUD
LONG TERM...MK
AVIATION...SMF
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1005 AM EST THU DEC 3 2015
.UPDATE...
NEAR TERM FOR THE REST OF TODAY HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 331 AM EST THU DEC 3 2015
HIGH PRESSURE WILL RESULT IN DRY CONDITIONS THROUGH THE WEEKEND
WITH A WEAK WARMING TREND. THE ONLY CHANCES FOR RAIN WILL BE
ACROSS THE SOUTHERN PORTIONS OF CENTRAL INDIANA ON SUNDAY NIGHT
WHEN A LOW PRESSURE SYSTEM PASSES THROUGH THE TENNESSEE VALLEY.
&&
.NEAR TERM /REST OF TODAY/...
ISSUED AT 1005 AM EST THU DEC 3 2015
SATELLITE INDICATES STRATUS WAS ACROSS OUR FAR NORTHEAST SECTIONS ALONG
AND EAST OF A ANDERSON TO NEW CASTLE LINE AND ALSO HAD SPREAD INTO
NORTHWEST SECTIONS WEST OF LAFAYETTE. RUC MODEL INDICATES STRATUS WILL
SPREAD SOUTH...WHILE THE NAM CLEAR IT OUT EVERYWHERE. WILL GO WITH A
COMPROMISE WITH A LITTLE MORE CLOUDS OVER NORTHWEST AND NORTHEAST SECTIONS
BUT OTHERWISE MOSTLY SUNNY CENTRAL AND SOUTH.
HIGH PRESSURE OVER MISSOURI WILL MOVE TO SOUTHWEST INDIANA BY THIS EVENING.
CONCERNING TEMPERATURES...DROPPED THEM SLIGHTLY OVER NORTHWEST AND NORTHEAST
SECTIONS WITH MORE CLOUDS. OTHERWISE...LOWER 40S WILL BE THE RULE MOST OTHER
AREAS WITH MIDDLE 40S FAR SOUTHWEST.
&&
.SHORT TERM /TONIGHT THROUGH SATURDAY NIGHT/...
ISSUED AT 331 AM EST THU DEC 3 2015
CENTRAL INDIANA WILL REMAIN UNDER THE INFLUENCE OF HIGH PRESSURE
FOR THE ENTIRE SHORT TERM PERIOD. AS A RESULT...DRY CONDITIONS
WITH ABOVE NORMAL TEMPERATURES WILL BE THE TREND. DAYTIME HIGHS
WILL TOP OFF IN THE UPPER 40S/LOW 50S WITH SOME POSSIBLE MID 50S
ACROSS THE SOUTHERN COUNTIES ON SATURDAY. MEANWHILE...OVERNIGHT
LOWS WILL REMAIN STEADY IN THE UPPER 20S/LOW 30S. MAVMOS NUMBERS
LOOK REASONABLE FOR THIS PATTERN.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY NIGHT/...
ISSUED AT 330 AM EST THU DEC 3 2015
MOSTLY DRY WEATHER AND SLIGHTLY ABOVE NORMAL TEMPERATURES ARE
EXPECTED LATE THIS WEEKEND THROUGH LATE NEXT WEEK COURTESY OF THE
MUCH TALKED ABOUT STRONG EL NINO.
THE 00Z ECMWF AND GFS BOTH BRING AN UPPER WAVE ACROSS THE AREA
SUNDAY NIGHT AS A WEAK SURFACE SYSTEM SLIDES EAST ACROSS THE
TENNESSEE VALLEY. ALTHOUGH THERE WILL NOT BE A LOT OF MOISTURE TO
WORK WITH...THE FORCING IS ENOUGH TO INCLUDE SMALL RAIN SHOWER
CHANCES ACROSS OUR SOUTHERN COUNTIES SUNDAY NIGHT. ANOTHER WEAKER
WAVE WILL MOVE THROUGH THE OHIO VALLEY LATE TUESDAY. HOWEVER...WITH
LESS FORCING AND LITTLE MOISTURE...WILL GO WITH A DRY FORECAST. ON
FINAL WAVE LOOKS TO MOVE THROUGH SOMEWHERE ACROSS THE GREAT LAKES OR
OHIO VALLEY WEDNESDAY NIGHT. HOWEVER...THE MODELS ARE WAY APART ON
TIMING AND STRENGTH AND BOTH SHOW LIMITED MOISTURE.
LOW LEVEL THERMAL AND SKY COVER PROGS ALONG WITH THE OVERALL
SYNOPTIC PATTERN LINE UP NICELY WITH THE REGIONAL BLEND REGARDING
TEMPERATURES. LOOK FOR AFTERNOON HIGHS IN THE MID 40S TO THE LOWER
50S AND LOWS IN THE 30S.
&&
AVIATION /DISCUSSION FOR THE 031200Z TAF ISSUANCE/...
ISSUED AT 957 AM EST THU DEC 3 2015
1440Z UPDATE...NO CHANGES NEEDED AT THIS TIME. PREVIOUS DISCUSSION
FOLLOWS.
COULD SEE SOME BRIEF MVFR OR WORSE FOG THROUGH
13Z...OTHERWISE...MAINLY VFR CONDITIONS TODAY. MVFR STRATUS DECK
OVER NORTHERN AND WEST CENTRAL ILLINOIS SHOULD MOVE NEAR OR NORTH OF
LAF AFTER 15Z...BUT CONFIDENCE IS NOT GREAT...SO WILL JUST GO WITH
BROKEN VFR CEILINGS THERE AFTER 15Z AND CLEAR ELSEWHERE PER MODEL RH
TIME SECTIONS AND CU DEVELOPMENT PROGS.
RH TIME SECTIONS SUGGEST CLEAR SKIES TONIGHT. ALSO...COULD SEE
SOME FOG OVERNIGHT...BUT CHANCES TOO LOW TO MENTION THIS EARLY.
WEST WINDS LESS THAN 10 KNOTS WILL BE LIGHT AND SOUTHWEST TONIGHT.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...TDUD
NEAR TERM...JH
SHORT TERM...TDUD
LONG TERM...MK
AVIATION...SMF/MK
AREA FORECAST DISCUSSION
National Weather Service Paducah KY
1126 PM CST WED DEC 2 2015
.UPDATE...
Issued at 1126 PM CST WED DEC 2 2015
Aviation update.
&&
.SHORT TERM...(This evening through Friday night)
Issued at 214 PM CST WED DEC 2 2015
It appears the GFS is/has been modeling the low layer cloud
field/embedded pcpn pertaining to the wrap around spiral bands
rotating south of the Low track today. A close examination of the
GFS20 vs the NAM12 Modeled Sounding data reveals this in better
detail, and the net effect will be a sliver of isolated pops for
our northern most tier of counties/partial counties for snow
showers this evening/early night. Amounts should be minuscule and
melt upon grounding.
After tonight, dry/cold air advection more firmly overtakes the
entire atmospheric column, as surface High pressure anchors across
the Commonwealth. This will lead to 40s tmrw, again
Friday/approaching 50, with mainly upper half 20s/nr 30 each
night through the remainder of the work week.
.LONG TERM...(Saturday through Wednesday)
Issued at 214 PM CST WED DEC 2 2015
At the beginning of the extended period, high pressure at the sfc
and aloft over the PAH forecast area will begin to give way to srly
low level flow ahead of a developing mid level shrtwv trof.
The forward speed and evolution of the trof continues to be in
question by the med range models as it is shown to dive into the
central Plains midway through the weekend. Some model solutions
suggest an fast open wave (UKMET) and some favor a slower closed
low. The deterministic 12Z GFS had an especially srly, slow, and
deep solution, which affected the initialization blend all the way
into Tue. The GFS ensemble means even had a closed low in the data
by early Mon. WPC appeared to gravitate toward a faster, ensemble-
mean-dominated trend. Sfc reflection is limited, and it is an
educated guess as to what the sfc wind fields will look like from
Sun through Tue.
For this forecast package, due to timing/coverage uncertainty in the
pcpn fields, we will go with no more than slight chances of rain
showers for most of the region Sun through Mon, with just a sliver
of PoP remaining in the srn Pennyrile Mon night. This was only a
modest deviation from the initialization blend, in fact. Dry weather
is forecast beyond Mon night, with not a whole lot of change in the
near-seasonable temps with time.
&&
.AVIATION...
Issued at 1126 PM CST WED DEC 2 2015
Expect mainly VFR conditions through daybreak with NW winds around 5
kts. Just a few passing clouds associated with an upper low moving
SE across the Ohio Valley. Should be mainly clear Thursday with
light winds.
&&
.PAH Watches/Warnings/Advisories...
IL...NONE.
MO...NONE.
IN...NONE.
KY...NONE.
&&
$$
Area Forecast Discussion
National Weather Service Louisville KY
1216 AM EST THU DEC 3 2015
...Updated Aviation Discussion...
...Forecast Update...
Issued at 840 PM EST Wed Dec 2 2015
A band of slightly heavier precipitation has moved into southern IN
now and will track ESE into north central KY over the next few
hours. Winds will briefly pick up with this precipitation with gusts
of 20-30 mph possible. Still maybe a chance for a very light dusting
of snow on elevated surfaces, but think most areas will see no
accumulation. Updated pops to increase them across portions of
southern IN and near the Ohio River with the band coming through.
Issued at 552 PM EST Wed Dec 2 2015
Just a few showers are left over from the rounds of precipitation
that moved through this afternoon. There were multiple reports of
graupel with these showers and some areas across the Bluegrass could
still see some of this over the next hour or two. The next area of
precipitation to move in is currently located over southwestern IN
and east central IL. Thinking remains largely the same with this
moving into southern IN counties between 00-01Z. Models then have it
weakening as the evening goes on. Recent AMDAR soundings from SDF do
show steep low level lapse rates up to -10 to -11C so snow showers
will certainly be a possibility. However, do not expect anything but
a dusting at best and briefly reduced visibilities from this
activity.
.SHORT TERM (Now through Thursday Night)...
Issued at 200 PM EST Wed Dec 2 2015
Main forecast concern this period is precip type with showers
expected ahead of an upper low now dropping south-southeast across
northern Illinois. The center of this feature will be over the
central IL/IN border by 00Z, and model soundings continue to show
our north and northeast zones saturated just up to the dendritic
growth zone, especially the latest NAM. The GFS and RUC are not as
robust, but given possibility and the axis of coldest temperatures
aloft swinging through at that point have kept in the snow or rain
shower chances through the evening hours. Given breezy conditions,
would not be surprised to see some briefly lower vsby in any heavier
snow showers across our northeast.
High pressure will build in slowly from the west for Thursday and
Thursday night, making for temperatures a little below
normal...though skies will be sunnier compared to the last few days.
.LONG TERM (Friday through Wednesday)...
Issued at 200 PM EST Wed Dec 2 2015
High pressure will be over us Friday and then just to our east
Saturday. For Sunday and upper low moves across the Central Plains.
Forecast models, not surprisingly, differ in timing of this low
moving towards our region, with the 00Z Euro and the latest GEM
showing it right over our longitude by Monday morning, whereas the
GFS slows the low down and moves it into Deep South. The first camp
would bring precip in here Sunday night, whereas the latter holds it
off until Monday night. The 00Z GEFS has a high spread toward the
Euro and GEM solution, so have to keep in some pops Sunday night.
After that system, and assuming the Euro/GEM solution is the correct
choice, the next system drops into the Central Plains Wednesday.
There should be enough distance between these two systems to
preclude precip chances advertised by the GFS (which given it`s
slower solution has the two phasing a little and keeping enough
moisture around to generater rain chances). Will go dry for
Wednesday.
&&
.AVIATION (06Z TAF Update)...
Updated at 1216 AM EST Thu Dec 3 2015
Early morning radar returns show lingering line of showers/snow
flurries pushing eastward across the region. This activity has
already cleared KSDF and KBWG and will primarily affect KLEX over the
next 2 hours or so. Given the rather sporadic nature of the band,
will keep VCSH in at KLEX for this issuance through 03/08Z.
Otherwise, expect MVFR ceilings to rise to VFR overnight at
KSDF/KBWG with skies becoming SKC by morning. Northwest winds of 8-
10kts will be possible with some gusts up to 18-20kts very early
this morning. Expect winds to diminish by 03/07-08Z at KSDF.
Over at KLEX, southwest winds will start off the TAF period and then
shift around to the northwest after 03/07-08Z.
Outlook for the day on Thursday, VFR ceilings and visibilities with
light northwesterly winds.
&&
.LMK Watches/Warnings/Advisories...
KY...NONE.
IN...NONE.
&&
$$
Update.........EER
Short Term.....RJS
Long Term......RJS
Aviation.......MJ
AREA FORECAST DISCUSSION
NWS CARIBOU ME
1108 AM EST THU DEC 3 2015
.SYNOPSIS...
LOW PRESSURE WILL INTENSIFY IN THE BAY OF FUNDY THIS AFTERNOON THEN
TRACK ACROSS NOVA SCOTIA TONIGHT. HIGH PRESSURE WILL BUILD ACROSS
THE REGION FRIDAY NIGHT INTO EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
11:10 AM UDPATE...PRECIPITATION IS GRADUALLY INCREASING IN
COVERAGE OVER THE NORTH AS THE STORM ORGANIZES ALONG THE COAST.
MIXED RAIN AND SNOW SHOULD CHANGE TO ALL SNOW OVER THE NORTH EARLY
THIS AFTERNOON AND BECOMING HEAVY FOR A PERIOD LATE THIS AFTERNOON
INTO THIS EVENING BEFORE THE STORM QUICKLY MOVES AWAY TO THE EAST.
600 AM UPDATE: NO SIG CHGS TO THE GOING FCST. LATEST HRRR MODEL
SIM RADAR REF SHOWS PRECIP MOVG BACK INTO THE FA FROM THE W BY MID
MORN WITH RN TRANSITIONING TO SN ACROSS THE ME N WOODS LATE THIS
MORN AS COLDER LLVL AIR WORKS SWRD FROM QB...WITH THIS TRANSITION
SPREADING SWRD IN CNTRL...SRN AROOSTOOK...NRN PENOBSCOT AND NRN
AND CNTRL PISCATAQUIS COUNTIES MIDDAY INTO ERLY AFTN. FCST QPF
AND IMPLIED SNFL DISTRIBUTION THRU THIS EVE IS NOT OUT OF LN FROM
WHAT WE CURRENTLY HAVE.
ORGNL DISC: MOST OF THE SYNOPTIC SCALE MODELS SHOW THE POTENTIAL
HEAVIEST SNFL OVR N CNTRL PTNS OF THE FA AFT RN CHGS TO SN FROM N
TO S ACROSS THE FA BEGINNING LATER THIS MORN AND CONTG INTO THE
AFTN. SOME MODELS LIKE THE 00Z DTMNSTC GFS HINT AT TWO BANDS OF
HEAVIER SNFL RATES ASSOCIATED WITH THE DEFORMATION ZONE OF THE
UPPER LOW AS IT SCOOTS FAIRLY QUICKLY ESE OVR CNTRL AND SRN PTNS
OF THE FA THIS AFTN AND ERLY EVE. THIS RELATIVELY QUICK MOTION OF
THE UPPER LOW COULD LIMIT THE DURATION OF HVY SN BANDING OVR ANY
PARTICULAR LCTNS TO A FEW HRS...BUT THIS IS ALL IT TAKES TO REACH
WRNG CRITERIA SNFL IF SN RATES ARE 1 TO 2 INCHES PER HR.
SUBSEQUENTLY... THE CORRIDOR ZONE OF HEAVIEST SNFL WE CURRENTLY
SHOW COULD BE A SIMPLIFICATION OF WHAT ACTUALLY OCCURS IF THIS
EVENT IS MULTI- BANDED...HOWEVER LATEST FCST HRRR SIM RADAR
SUPPORTS THE 30 MILE SWRD SHIFT OF THE MAX SN AXIS WE MADE FROM
THE LAST MAJOR FCST UPDATE YSTDY AFTN. WINDS WILL ALSO INCREASE ON
THE BACK SIDE OF THE SFC LOW LATE THIS AFTN AND EVE TO PRODUCE
PATCHY BLSN...WHICH WE INCLUDE FOR THOSE LCTNS REACHING AND
EXCEEDING LIKELY POPS AND SFC TEMPS LESS THAN 30.5 DEG F.
OTHERWISE...SN WILL TAPER TO SCT SN SHWRS BY LATE EVE AND THEN END
W TO E ACROSS THE FA OVRNGT...WITH PERHAPS SOME BREAKS IN CLDNSS....
SPCLY S OF KMLT LATE TNGT INTO ERLY FRI MORN AS TEMPS CONT TO FALL
INTO THE LOWER TO MID 20S SOUTH AND TEENS N FOR OVRNGT LOWS.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AN UPPER TROUGH AND ASSOCIATED SURFACE COLD FRONT WILL CROSS
FRIDAY. THIS WILL PRODUCE CLOUDS AND SOME WEAK SNOW SHOWERS IN
NORTHERN ZONES. THESE SNOW SHOWERS...OR FLURRIES...WILL TOP OUT
UNDER H850. THUS...LITTLE ACCUMULATION IS EXPECTED. TOWARDS BANGOR
AND DOWN EAST...LESS CLOUD COVER AND DRY CONDITIONS ARE FORECAST.
HIGHS WILL RANGE FROM THE UPPER 30S TOWARDS BUCKSPORT AND MACHIAS
TO UPPER 20S FURTHER NORTH IN MADAWASKA AND FORT KENT. THERE WILL
NOT BE MUCH COLD AIR BEHIND THE FRONT. LOWS WILL GENERALLY BE IN
THE 20S. A FEW READINGS IN THE TEENS WOULDN`T BE ANY SURPRISE IN
THE ALLAGASH AND SAINT JOHN VALLEY. AN UPPER RIDGE BUILDS IN
FRIDAY NIGHT AND WILL SET THE STAGE FOR A PERSISTENT SUBSIDENCE
INVERSION SATURDAY INTO SUNDAY. THIS MEANS LOW CUMULUS WILL FORM
AND SPREAD OUT INTO STRATOCUMULUS AND REMAIN IN PLACE. THE ONLY
EXCEPTION WILL BE FOR BANGOR AND DOWN EAST WHERE THE WIND
DIRECTION SUGGESTS A GREATER DEGREE OF DOWNSLOPING. THESE CLOUDS
WILL LIMIT SATURDAY`S HIGHS TO THE LOW TO MID 30S NORTH AND UPPER
30S TO LOWER 40S FOR BANGOR AND DOWN EAST. LOWS SATURDAY NIGHT
WILL BE MOSTLY IN THE UPPER 20S. ANY UNFORESEEN BREAKS IN THE
CLOUDS COULD RESULT IN UPPER TEENS TO LOWER 20S.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
SUBSIDENCE INVERSIONS UNDER UPPER RIDGING WILL CONTINUE TO BE THE
STORY IN THE LONGER TERM WITH NO MAJOR STORM SYSTEMS EXPECTED AT
THIS POINT. THERE IS A DRY COLD FRONT CROSSING ON MONDAY AND A
STORM SYSTEM THAT WILL MOVE SOUTH OF THE AREA WEDNESDAY. ON THE
WEDNESDAY STORM...ADDED SLIGHT CHANCE POPS FOR MOST OF THE AREA
AND CHANCE POPS IN WASHINGTON COUNTY FOLLOWING GEFS GUIDANCE.
DUE TO THE SUBSIDENCE INVERSION...HAVE GONE HIGHER THAN MOST
GUIDANCE FOR CLOUDS THROUGH MOST OF THE PERIOD WITH CLEARING MORE
LIKELY DUE TO DOWNSLOPING RATHER THAN DIURNAL HEATING. THE
INVERSION ALSO KEEPS TEMPERATURES IN A RANGE OF 20S AT NIGHT AND
30S IN THE DAYTIME. THE BEST SHOT OF A COLDER NIGHT APPEARS TO BE
MONDAY NIGHT AFTER THE DRY COLD FRONT PASSAGE WITH A RIDGE
BUILDING THROUGH THE NIGHT. HOWEVER...BY TUESDAY AFTERNOON...A
MOIST EASTERLY FLOW SEEMS LIKELY TO REESTABLISH CLOUDINESS UNDER
THE INVERSION.
&&
.AVIATION /16Z THURSDAY THROUGH MONDAY/...
NEAR TERM: IFR CONDITIONS WILL CONT IN RN/FOG ACROSS THE TAF SITES
THIS MORN...TRANSITIONING TO SN FROM N TO S ACROSS THE SITES
BEGINNING LATE THIS MORN AT KFVE AND REACHING KBGR AND KBHB BY
EVE. IFR CONDITIONS IN SN THIS EVE IMPROVE W TO E OVRNGT TO MVFR
AS SN TAPERS TO SCT SN SHWRS AND THEN VFR FOR DOWNEAST SITES
LATE TNGT INTO ERLY FRI MORN.
SHORT TERM: THE PREDOMINANT CONDITION NORTH OF HUL WILL BE LOW
MVFR CIGS...WITH TEMPORARY DROPS JUST BELOW 1000FT INTO THE IFR
CATEGORY. BGR AND BHB WILL BE MOSTLY VFR. ON FRIDAY...EXPECT
SCATTERED SNSH WITH TOPS UNDER FL050 IN AREAS NORTH OF HUL.
&&
.MARINE...
NEAR TERM: WILL CONT WITH THE GLW OUTER MZS AND SCA FOR THE INNER
BAY/HARBOR MZ LATER TDY INTO TNGT AS N TO NW WINDS INCREASE ON THE
BACK SIDE OF THE DEPARTING LOW...WITH WINDS AND SEAS SLOWLY
SUBSIDING LATE TNGT INTO ERLY FRI MORN. WE WENT ABOUT A FOOT
HIGHER THAN WW3 WV GUIDANCE FOR THE NEAR TERM BASED ON TRENDS
SHOWN IN LATEST BUOY OBS.
SHORT TERM: NO SGNFCNT WEATHER IS EXPECTED UNTIL THE POSSIBILITY
ON AN SCA TOWARDS THE MIDDLE OF NEXT WEEK.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...WINTER STORM WARNING UNTIL 1 AM EST FRIDAY FOR MEZ001>006-010.
WINTER WEATHER ADVISORY UNTIL 1 AM EST FRIDAY FOR MEZ011-031-
032.
MARINE...SMALL CRAFT ADVISORY FROM 5 PM THIS AFTERNOON TO 3 AM EST
FRIDAY FOR ANZ052.
GALE WARNING FROM 5 PM THIS AFTERNOON TO 3 AM EST FRIDAY FOR
ANZ050-051.
&&
$$
NEAR TERM...VJN/MCB
SHORT TERM...MCW
LONG TERM...MCW
AVIATION...VJN/MCW
MARINE...VJN/MCW
AREA FORECAST DISCUSSION
NWS CARIBOU ME
815 AM EST THU DEC 3 2015
.SYNOPSIS...
LOW PRESSURE WILL INTENSIFY IN THE BAY OF FUNDY THIS AFTERNOON THEN
TRACK ACROSS NOVA SCOTIA TONIGHT. HIGH PRESSURE WILL BUILD ACROSS
THE REGION FRIDAY NIGHT INTO EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
8:15 AM UPDATE...PRECIPITATION IS EXPANDING ACROSS THE NORTH WITH
MOSTLY RAIN, AND WET SNOW MIXED IN WHERE IT`S A BIT HEAVIER.
FORECAST REMAINS ON TRACK WITH PRECIPITATION EXPECTED TO CHANGE TO
SNOW AND INCREASE IN COVERAGE TODAY.
600 AM UPDATE: NO SIG CHGS TO THE GOING FCST. LATEST HRRR MODEL
SIM RADAR REF SHOWS PRECIP MOVG BACK INTO THE FA FROM THE W BY MID
MORN WITH RN TRANSITIONING TO SN ACROSS THE ME N WOODS LATE THIS
MORN AS COLDER LLVL AIR WORKS SWRD FROM QB...WITH THIS TRANSITION
SPREADING SWRD IN CNTRL...SRN AROOSTOOK...NRN PENOBSCOT AND NRN
AND CNTRL PISCATAQUIS COUNTIES MIDDAY INTO ERLY AFTN. FCST QPF
AND IMPLIED SNFL DISTRIBUTION THRU THIS EVE IS NOT OUT OF LN FROM
WHAT WE CURRENTLY HAVE.
ORGNL DISC: MOST OF THE SYNOPTIC SCALE MODELS SHOW THE POTENTIAL
HEAVIEST SNFL OVR N CNTRL PTNS OF THE FA AFT RN CHGS TO SN FROM N
TO S ACROSS THE FA BEGINNING LATER THIS MORN AND CONTG INTO THE
AFTN. SOME MODELS LIKE THE 00Z DTMNSTC GFS HINT AT TWO BANDS OF
HEAVIER SNFL RATES ASSOCIATED WITH THE DEFORMATION ZONE OF THE
UPPER LOW AS IT SCOOTS FAIRLY QUICKLY ESE OVR CNTRL AND SRN PTNS
OF THE FA THIS AFTN AND ERLY EVE. THIS RELATIVELY QUICK MOTION OF
THE UPPER LOW COULD LIMIT THE DURATION OF HVY SN BANDING OVR ANY
PARTICULAR LCTNS TO A FEW HRS...BUT THIS IS ALL IT TAKES TO REACH
WRNG CRITERIA SNFL IF SN RATES ARE 1 TO 2 INCHES PER HR.
SUBSEQUENTLY... THE CORRIDOR ZONE OF HEAVIEST SNFL WE CURRENTLY
SHOW COULD BE A SIMPLIFICATION OF WHAT ACTUALLY OCCURS IF THIS
EVENT IS MULTI- BANDED...HOWEVER LATEST FCST HRRR SIM RADAR
SUPPORTS THE 30 MILE SWRD SHIFT OF THE MAX SN AXIS WE MADE FROM
THE LAST MAJOR FCST UPDATE YSTDY AFTN. WINDS WILL ALSO INCREASE ON
THE BACK SIDE OF THE SFC LOW LATE THIS AFTN AND EVE TO PRODUCE
PATCHY BLSN...WHICH WE INCLUDE FOR THOSE LCTNS REACHING AND
EXCEEDING LIKELY POPS AND SFC TEMPS LESS THAN 30.5 DEG F.
OTHERWISE...SN WILL TAPER TO SCT SN SHWRS BY LATE EVE AND THEN END
W TO E ACROSS THE FA OVRNGT...WITH PERHAPS SOME BREAKS IN CLDNSS....
SPCLY S OF KMLT LATE TNGT INTO ERLY FRI MORN AS TEMPS CONT TO FALL
INTO THE LOWER TO MID 20S SOUTH AND TEENS N FOR OVRNGT LOWS.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AN UPPER TROUGH AND ASSOCIATED SURFACE COLD FRONT WILL CROSS
FRIDAY. THIS WILL PRODUCE CLOUDS AND SOME WEAK SNOW SHOWERS IN
NORTHERN ZONES. THESE SNOW SHOWERS...OR FLURRIES...WILL TOP OUT
UNDER H850. THUS...LITTLE ACCUMULATION IS EXPECTED. TOWARDS BANGOR
AND DOWN EAST...LESS CLOUD COVER AND DRY CONDITIONS ARE FORECAST.
HIGHS WILL RANGE FROM THE UPPER 30S TOWARDS BUCKSPORT AND MACHIAS
TO UPPER 20S FURTHER NORTH IN MADAWASKA AND FORT KENT. THERE WILL
NOT BE MUCH COLD AIR BEHIND THE FRONT. LOWS WILL GENERALLY BE IN
THE 20S. A FEW READINGS IN THE TEENS WOULDN`T BE ANY SURPRISE IN
THE ALLAGASH AND SAINT JOHN VALLEY. AN UPPER RIDGE BUILDS IN
FRIDAY NIGHT AND WILL SET THE STAGE FOR A PERSISTENT SUBSIDENCE
INVERSION SATURDAY INTO SUNDAY. THIS MEANS LOW CUMULUS WILL FORM
AND SPREAD OUT INTO STRATOCUMULUS AND REMAIN IN PLACE. THE ONLY
EXCEPTION WILL BE FOR BANGOR AND DOWN EAST WHERE THE WIND
DIRECTION SUGGESTS A GREATER DEGREE OF DOWNSLOPING. THESE CLOUDS
WILL LIMIT SATURDAY`S HIGHS TO THE LOW TO MID 30S NORTH AND UPPER
30S TO LOWER 40S FOR BANGOR AND DOWN EAST. LOWS SATURDAY NIGHT
WILL BE MOSTLY IN THE UPPER 20S. ANY UNFORESEEN BREAKS IN THE
CLOUDS COULD RESULT IN UPPER TEENS TO LOWER 20S.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
SUBSIDENCE INVERSIONS UNDER UPPER RIDGING WILL CONTINUE TO BE THE
STORY IN THE LONGER TERM WITH NO MAJOR STORM SYSTEMS EXPECTED AT
THIS POINT. THERE IS A DRY COLD FRONT CROSSING ON MONDAY AND A
STORM SYSTEM THAT WILL MOVE SOUTH OF THE AREA WEDNESDAY. ON THE
WEDNESDAY STORM...ADDED SLIGHT CHANCE POPS FOR MOST OF THE AREA
AND CHANCE POPS IN WASHINGTON COUNTY FOLLOWING GEFS GUIDANCE.
DUE TO THE SUBSIDENCE INVERSION...HAVE GONE HIGHER THAN MOST
GUIDANCE FOR CLOUDS THROUGH MOST OF THE PERIOD WITH CLEARING MORE
LIKELY DUE TO DOWNSLOPING RATHER THAN DIURNAL HEATING. THE
INVERSION ALSO KEEPS TEMPERATURES IN A RANGE OF 20S AT NIGHT AND
30S IN THE DAYTIME. THE BEST SHOT OF A COLDER NIGHT APPEARS TO BE
MONDAY NIGHT AFTER THE DRY COLD FRONT PASSAGE WITH A RIDGE
BUILDING THROUGH THE NIGHT. HOWEVER...BY TUESDAY AFTERNOON...A
MOIST EASTERLY FLOW SEEMS LIKELY TO REESTABLISH CLOUDINESS UNDER
THE INVERSION.
&&
.AVIATION /13Z THURSDAY THROUGH MONDAY/...
NEAR TERM: IFR CONDITIONS WILL CONT IN RN/FOG ACROSS THE TAF SITES
THIS MORN...TRANSITIONING TO SN FROM N TO S ACROSS THE SITES
BEGINNING LATE THIS MORN AT KFVE AND REACHING KBGR AND KBHB BY
EVE. IFR CONDITIONS IN SN THIS EVE IMPROVE W TO E OVRNGT TO MVFR
AS SN TAPERS TO SCT SN SHWRS AND THEN VFR FOR DOWNEAST SITES
LATE TNGT INTO ERLY FRI MORN.
SHORT TERM: THE PREDOMINANT CONDITION NORTH OF HUL WILL BE LOW
MVFR CIGS...WITH TEMPORARY DROPS JUST BELOW 1000FT INTO THE IFR
CATEGORY. BGR AND BHB WILL BE MOSTLY VFR. ON FRIDAY...EXPECT
SCATTERED SNSH WITH TOPS UNDER FL050 IN AREAS NORTH OF HUL.
&&
.MARINE...
NEAR TERM: WILL CONT WITH THE GLW OUTER MZS AND SCA FOR THE INNER
BAY/HARBOR MZ LATER TDY INTO TNGT AS N TO NW WINDS INCREASE ON THE
BACK SIDE OF THE DEPARTING LOW...WITH WINDS AND SEAS SLOWLY
SUBSIDING LATE TNGT INTO ERLY FRI MORN. WE WENT ABOUT A FOOT
HIGHER THAN WW3 WV GUIDANCE FOR THE NEAR TERM BASED ON TRENDS
SHOWN IN LATEST BUOY OBS.
SHORT TERM: NO SGNFCNT WEATHER IS EXPECTED UNTIL THE POSSIBILITY
ON AN SCA TOWARDS THE MIDDLE OF NEXT WEEK.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...WINTER STORM WARNING UNTIL 1 AM EST FRIDAY FOR MEZ001>006-010.
WINTER WEATHER ADVISORY UNTIL 1 AM EST FRIDAY FOR MEZ011-031-
032.
MARINE...SMALL CRAFT ADVISORY FROM 5 PM THIS AFTERNOON TO 3 AM EST
FRIDAY FOR ANZ052.
GALE WARNING FROM 5 PM THIS AFTERNOON TO 3 AM EST FRIDAY FOR
ANZ050-051.
&&
$$
NEAR TERM...VJN/MCB
SHORT TERM...MCW
LONG TERM...MCW
AVIATION...VJN/MCW
MARINE...VJN/MCW
AREA FORECAST DISCUSSION
NWS CARIBOU ME
614 AM EST THU DEC 3 2015
.SYNOPSIS...
LOW PRESSURE WILL INTENSIFY IN THE BAY OF FUNDY THIS AFTERNOON THEN
TRACK ACROSS NOVA SCOTIA TONIGHT. HIGH PRESSURE WILL BUILD ACROSS
THE REGION FRIDAY NIGHT INTO EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
600 AM UPDATE: NO SIG CHGS TO THE GOING FCST. LATEST HRRR MODEL
SIM RADAR REF SHOWS PRECIP MOVG BACK INTO THE FA FROM THE W BY MID
MORN WITH RN TRANSITIONING TO SN ACROSS THE ME N WOODS LATE THIS
MORN AS COLDER LLVL AIR WORKS SWRD FROM QB...WITH THIS TRANSITION
SPREADING SWRD IN CNTRL...SRN AROOSTOOK...NRN PENOBSCOT AND NRN
AND CNTRL PISCATAQUIS COUNTIES MIDDAY INTO ERLY AFTN. FCST QPF
AND IMPLIED SNFL DISTRIBUTION THRU THIS EVE IS NOT OUT OF LN FROM
WHAT WE CURRENTLY HAVE.
ORGNL DISC: MOST OF THE SYNOPTIC SCALE MODELS SHOW THE POTENTIAL
HEAVIEST SNFL OVR N CNTRL PTNS OF THE FA AFT RN CHGS TO SN FROM N
TO S ACROSS THE FA BEGINNING LATER THIS MORN AND CONTG INTO THE
AFTN. SOME MODELS LIKE THE 00Z DTMNSTC GFS HINT AT TWO BANDS OF
HEAVIER SNFL RATES ASSOCIATED WITH THE DEFORMATION ZONE OF THE
UPPER LOW AS IT SCOOTS FAIRLY QUICKLY ESE OVR CNTRL AND SRN PTNS
OF THE FA THIS AFTN AND ERLY EVE. THIS RELATIVELY QUICK MOTION OF
THE UPPER LOW COULD LIMIT THE DURATION OF HVY SN BANDING OVR ANY
PARTICULAR LCTNS TO A FEW HRS...BUT THIS IS ALL IT TAKES TO REACH
WRNG CRITERIA SNFL IF SN RATES ARE 1 TO 2 INCHES PER HR.
SUBSEQUENTLY... THE CORRIDOR ZONE OF HEAVIEST SNFL WE CURRENTLY
SHOW COULD BE A SIMPLIFICATION OF WHAT ACTUALLY OCCURS IF THIS
EVENT IS MULTI- BANDED...HOWEVER LATEST FCST HRRR SIM RADAR
SUPPORTS THE 30 MILE SWRD SHIFT OF THE MAX SN AXIS WE MADE FROM
THE LAST MAJOR FCST UPDATE YSTDY AFTN. WINDS WILL ALSO INCREASE ON
THE BACK SIDE OF THE SFC LOW LATE THIS AFTN AND EVE TO PRODUCE
PATCHY BLSN...WHICH WE INCLUDE FOR THOSE LCTNS REACHING AND
EXCEEDING LIKELY POPS AND SFC TEMPS LESS THAN 30.5 DEG F.
OTHERWISE...SN WILL TAPER TO SCT SN SHWRS BY LATE EVE AND THEN END
W TO E ACROSS THE FA OVRNGT...WITH PERHAPS SOME BREAKS IN CLDNSS....
SPCLY S OF KMLT LATE TNGT INTO ERLY FRI MORN AS TEMPS CONT TO FALL
INTO THE LOWER TO MID 20S SOUTH AND TEENS N FOR OVRNGT LOWS.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AN UPPER TROUGH AND ASSOCIATED SURFACE COLD FRONT WILL CROSS
FRIDAY. THIS WILL PRODUCE CLOUDS AND SOME WEAK SNOW SHOWERS IN
NORTHERN ZONES. THESE SNOW SHOWERS...OR FLURRIES...WILL TOP OUT
UNDER H850. THUS...LITTLE ACCUMULATION IS EXPECTED. TOWARDS BANGOR
AND DOWN EAST...LESS CLOUD COVER AND DRY CONDITIONS ARE FORECAST.
HIGHS WILL RANGE FROM THE UPPER 30S TOWARDS BUCKSPORT AND MACHIAS
TO UPPER 20S FURTHER NORTH IN MADAWASKA AND FORT KENT. THERE WILL
NOT BE MUCH COLD AIR BEHIND THE FRONT. LOWS WILL GENERALLY BE IN
THE 20S. A FEW READINGS IN THE TEENS WOULDN`T BE ANY SURPRISE IN
THE ALLAGASH AND SAINT JOHN VALLEY. AN UPPER RIDGE BUILDS IN
FRIDAY NIGHT AND WILL SET THE STAGE FOR A PERSISTENT SUBSIDENCE
INVERSION SATURDAY INTO SUNDAY. THIS MEANS LOW CUMULUS WILL FORM
AND SPREAD OUT INTO STRATOCUMULUS AND REMAIN IN PLACE. THE ONLY
EXCEPTION WILL BE FOR BANGOR AND DOWN EAST WHERE THE WIND
DIRECTION SUGGESTS A GREATER DEGREE OF DOWNSLOPING. THESE CLOUDS
WILL LIMIT SATURDAY`S HIGHS TO THE LOW TO MID 30S NORTH AND UPPER
30S TO LOWER 40S FOR BANGOR AND DOWN EAST. LOWS SATURDAY NIGHT
WILL BE MOSTLY IN THE UPPER 20S. ANY UNFORESEEN BREAKS IN THE
CLOUDS COULD RESULT IN UPPER TEENS TO LOWER 20S.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
SUBSIDENCE INVERSIONS UNDER UPPER RIDGING WILL CONTINUE TO BE THE
STORY IN THE LONGER TERM WITH NO MAJOR STORM SYSTEMS EXPECTED AT
THIS POINT. THERE IS A DRY COLD FRONT CROSSING ON MONDAY AND A
STORM SYSTEM THAT WILL MOVE SOUTH OF THE AREA WEDNESDAY. ON THE
WEDNESDAY STORM...ADDED SLIGHT CHANCE POPS FOR MOST OF THE AREA
AND CHANCE POPS IN WASHINGTON COUNTY FOLLOWING GEFS GUIDANCE.
DUE TO THE SUBSIDENCE INVERSION...HAVE GONE HIGHER THAN MOST
GUIDANCE FOR CLOUDS THROUGH MOST OF THE PERIOD WITH CLEARING MORE
LIKELY DUE TO DOWNSLOPING RATHER THAN DIURNAL HEATING. THE
INVERSION ALSO KEEPS TEMPERATURES IN A RANGE OF 20S AT NIGHT AND
30S IN THE DAYTIME. THE BEST SHOT OF A COLDER NIGHT APPEARS TO BE
MONDAY NIGHT AFTER THE DRY COLD FRONT PASSAGE WITH A RIDGE
BUILDING THROUGH THE NIGHT. HOWEVER...BY TUESDAY AFTERNOON...A
MOIST EASTERLY FLOW SEEMS LIKELY TO REESTABLISH CLOUDINESS UNDER
THE INVERSION.
&&
.AVIATION /08Z THURSDAY THROUGH MONDAY/...
NEAR TERM: IFR CONDITIONS WILL CONT IN RN/FOG ACROSS THE TAF SITES
THIS MORN...TRANSITIONING TO SN FROM N TO S ACROSS THE SITES
BEGINNING LATE THIS MORN AT KFVE AND REACHING KBGR AND KBHB BY
EVE. IFR CONDITIONS IN SN THIS EVE IMPROVE W TO E OVRNGT TO MVFR
AS SN TAPERS TO SCT SN SHWRS AND THEN VFR FOR DOWNEAST SITES
LATE TNGT INTO ERLY FRI MORN.
SHORT TERM: THE PREDOMINANT CONDITION NORTH OF HUL WILL BE LOW
MVFR CIGS...WITH TEMPORARY DROPS JUST BELOW 1000FT INTO THE IFR
CATEGORY. BGR AND BHB WILL BE MOSTLY VFR. ON FRIDAY...EXPECT
SCATTERED SNSH WITH TOPS UNDER FL050 IN AREAS NORTH OF HUL.
&&
.MARINE...
NEAR TERM: WILL CONT WITH THE GLW OUTER MZS AND SCA FOR THE INNER
BAY/HARBOR MZ LATER TDY INTO TNGT AS N TO NW WINDS INCREASE ON THE
BACK SIDE OF THE DEPARTING LOW...WITH WINDS AND SEAS SLOWLY
SUBSIDING LATE TNGT INTO ERLY FRI MORN. WE WENT ABOUT A FOOT
HIGHER THAN WW3 WV GUIDANCE FOR THE NEAR TERM BASED ON TRENDS
SHOWN IN LATEST BUOY OBS.
SHORT TERM: NO SGNFCNT WEATHER IS EXPECTED UNTIL THE POSSIBILITY
ON AN SCA TOWARDS THE MIDDLE OF NEXT WEEK.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...WINTER STORM WARNING FROM 8 AM THIS MORNING TO 1 AM EST FRIDAY
FOR MEZ001>006-010.
WINTER WEATHER ADVISORY FROM 8 AM THIS MORNING TO 1 AM EST
FRIDAY FOR MEZ011-031-032.
MARINE...SMALL CRAFT ADVISORY FROM 5 PM THIS AFTERNOON TO 3 AM EST
FRIDAY FOR ANZ052.
GALE WARNING FROM 5 PM THIS AFTERNOON TO 3 AM EST FRIDAY FOR
ANZ050-051.
&&
$$
NEAR TERM...VJN
SHORT TERM...MCW
LONG TERM...MCW
AVIATION...VJN/MCW
MARINE...VJN/MCW
AREA FORECAST DISCUSSION
NWS CARIBOU ME
445 AM EST THU DEC 3 2015
.SYNOPSIS...
LOW PRESSURE WILL INTENSIFY IN THE BAY OF FUNDY THIS AFTERNOON THEN
TRACK ACROSS NOVA SCOTIA TONIGHT. HIGH PRESSURE WILL BUILD ACROSS
THE REGION FRIDAY NIGHT INTO EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
MOST OF THE SYNOPTIC SCALE MODELS SHOW THE POTENTIAL HEAVIEST SNFL
OVR N CNTRL PTNS OF THE FA AFT RN CHGS TO SN FROM N TO S ACROSS
THE FA BEGINNING LATER THIS MORN AND CONTG INTO THE AFTN. SOME
MODELS LIKE THE 00Z DTMNSTC GFS HINT AT TWO BANDS OF HEAVIER SNFL
RATES ASSOCIATED WITH THE DEFORMATION ZONE OF THE UPPER LOW AS IT
SCOOTS FAIRLY QUICKLY ESE OVR CNTRL AND SRN PTNS OF THE FA THIS
AFTN AND ERLY EVE. THIS RELATIVELY QUICK MOTION OF THE UPPER LOW
COULD LIMIT THE DURATION OF HVY SN BANDING OVR ANY PARTICULAR
LCTNS TO A FEW HRS...BUT THIS IS ALL IT TAKES TO REACH WRNG
CRITERIA SNFL IF SN RATES ARE 1 TO 2 INCHES PER HR. SUBSEQUENTLY...
THE CORRIDOR ZONE OF HEAVIEST SNFL WE CURRENTLY SHOW COULD BE A
SIMPLIFICATION OF WHAT ACTUALLY OCCURS IF THIS EVENT IS MULTI-
BANDED...HOWEVER LATEST FCST HRRR SIM RADAR SUPPORTS THE 30 MILE
SWRD SHIFT OF THE MAX SN AXIS WE MADE FROM THE LAST MAJOR FCST
UPDATE YSTDY AFTN. WINDS WILL ALSO INCREASE ON THE BACK SIDE OF
THE SFC LOW LATE THIS AFTN AND EVE TO PRODUCE PATCHY BLSN...WHICH
WE INCLUDE FOR THOSE LCTNS REACHING AND EXCEEDING LIKELY POPS AND
SFC TEMPS LESS THAN 30.5 DEG F.
OTHERWISE...SN WILL TAPER TO SCT SN SHWRS BY LATE EVE AND THEN END
W TO E ACROSS THE FA OVRNGT...WITH PERHAPS SOME BREAKS IN CLDNSS....
SPCLY S OF KMLT LATE TNGT INTO ERLY FRI MORN AS TEMPS CONT TO FALL
INTO THE LOWER TO MID 20S SOUTH AND TEENS N FOR OVRNGT LOWS.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AN UPPER TROUGH AND ASSOCIATED SURFACE COLD FRONT WILL CROSS
FRIDAY. THIS WILL PRODUCE CLOUDS AND SOME WEAK SNOW SHOWERS IN
NORTHERN ZONES. THESE SNOW SHOWERS...OR FLURRIES...WILL TOP OUT
UNDER H850. THUS...LITTLE ACCUMULATION IS EXPECTED. TOWARDS BANGOR
AND DOWN EAST...LESS CLOUD COVER AND DRY CONDITIONS ARE FORECAST.
HIGHS WILL RANGE FROM THE UPPER 30S TOWARDS BUCKSPORT AND MACHIAS
TO UPPER 20S FURTHER NORTH IN MADAWASKA AND FORT KENT. THERE WILL
NOT BE MUCH COLD AIR BEHIND THE FRONT. LOWS WILL GENERALLY BE IN
THE 20S. A FEW READINGS IN THE TEENS WOULDN`T BE ANY SURPRISE IN
THE ALLAGASH AND SAINT JOHN VALLEY. AN UPPER RIDGE BUILDS IN
FRIDAY NIGHT AND WILL SET THE STAGE FOR A PERSISTENT SUBSIDENCE
INVERSION SATURDAY INTO SUNDAY. THIS MEANS LOW CUMULUS WILL FORM
AND SPREAD OUT INTO STRATOCUMULUS AND REMAIN IN PLACE. THE ONLY
EXCEPTION WILL BE FOR BANGOR AND DOWN EAST WHERE THE WIND
DIRECTION SUGGESTS A GREATER DEGREE OF DOWNSLOPING. THESE CLOUDS
WILL LIMIT SATURDAY`S HIGHS TO THE LOW TO MID 30S NORTH AND UPPER
30S TO LOWER 40S FOR BANGOR AND DOWN EAST. LOWS SATURDAY NIGHT
WILL BE MOSTLY IN THE UPPER 20S. ANY UNFORESEEN BREAKS IN THE
CLOUDS COULD RESULT IN UPPER TEENS TO LOWER 20S.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
SUBSIDENCE INVERSIONS UNDER UPPER RIDGING WILL CONTINUE TO BE THE
STORY IN THE LONGER TERM WITH NO MAJOR STORM SYSTEMS EXPECTED AT
THIS POINT. THERE IS A DRY COLD FRONT CROSSING ON MONDAY AND A
STORM SYSTEM THAT WILL MOVE SOUTH OF THE AREA WEDNESDAY. ON THE
WEDNESDAY STORM...ADDED SLIGHT CHANCE POPS FOR MOST OF THE AREA
AND CHANCE POPS IN WASHINGTON COUNTY FOLLOWING GEFS GUIDANCE.
DUE TO THE SUBSIDENCE INVERSION...HAVE GONE HIGHER THAN MOST
GUIDANCE FOR CLOUDS THROUGH MOST OF THE PERIOD WITH CLEARING MORE
LIKELY DUE TO DOWNSLOPING RATHER THAN DIURNAL HEATING. THE
INVERSION ALSO KEEPS TEMPERATURES IN A RANGE OF 20S AT NIGHT AND
30S IN THE DAYTIME. THE BEST SHOT OF A COLDER NIGHT APPEARS TO BE
MONDAY NIGHT AFTER THE DRY COLD FRONT PASSAGE WITH A RIDGE
BUILDING THROUGH THE NIGHT. HOWEVER...BY TUESDAY AFTERNOON...A
MOIST EASTERLY FLOW SEEMS LIKELY TO REESTABLISH CLOUDINESS UNDER
THE INVERSION.
&&
.AVIATION /08Z THURSDAY THROUGH MONDAY/...
NEAR TERM: IFR CONDITIONS WILL CONT IN RN/FOG ACROSS THE TAF SITES
THIS MORN...TRANSITIONING TO SN FROM N TO S ACROSS THE SITES
BEGINNING LATE THIS MORN AT KFVE AND REACHING KBGR AND KBHB BY
EVE. IFR CONDITIONS IN SN THIS EVE IMPROVE W TO E OVRNGT TO MVFR
AS SN TAPERS TO SCT SN SHWRS AND THEN VFR FOR DOWNEAST SITES
LATE TNGT INTO ERLY FRI MORN.
SHORT TERM: THE PREDOMINANT CONDITION NORTH OF HUL WILL BE LOW
MVFR CIGS...WITH TEMPORARY DROPS JUST BELOW 1000FT INTO THE IFR
CATEGORY. BGR AND BHB WILL BE MOSTLY VFR. ON FRIDAY...EXPECT
SCATTERED SNSH WITH TOPS UNDER FL050 IN AREAS NORTH OF HUL.
&&
.MARINE...
NEAR TERM: WILL CONT WITH THE GLW OUTER MZS AND SCA FOR THE INNER
BAY/HARBOR MZ LATER TDY INTO TNGT AS N TO NW WINDS INCREASE ON THE
BACK SIDE OF THE DEPARTING LOW...WITH WINDS AND SEAS SLOWLY
SUBSIDING LATE TNGT INTO ERLY FRI MORN. WE WENT ABOUT A FOOT
HIGHER THAN WW3 WV GUIDANCE FOR THE NEAR TERM BASED ON TRENDS
SHOWN IN LATEST BUOY OBS.
SHORT TERM: NO SGNFCNT WEATHER IS EXPECTED UNTIL THE POSSIBILITY ON
AN SCA TOWARDS THE MIDDLE OF NEXT WEEK.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...WINTER STORM WARNING FROM 8 AM THIS MORNING TO 1 AM EST FRIDAY
FOR MEZ001>006-010.
WINTER WEATHER ADVISORY FROM 8 AM THIS MORNING TO 1 AM EST
FRIDAY FOR MEZ011-031-032.
MARINE...SMALL CRAFT ADVISORY FROM 5 PM THIS AFTERNOON TO 3 AM EST
FRIDAY FOR ANZ052.
GALE WARNING FROM 5 PM THIS AFTERNOON TO 3 AM EST FRIDAY FOR
ANZ050-051.
&&
$$
NEAR TERM...VJN
SHORT TERM...MCW
LONG TERM...MCW
AVIATION...VJN/MCW
MARINE...VJN/MCW
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
1042 PM EST FRI DEC 4 2015
.SYNOPSIS...
RIDGE OF HIGH PRESSURE WILL BRING DRY WEATHER AND SLOWLY
MODERATING TEMPERATURES THROUGH THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
WITH 915PM UPDATE...MADE ADDITIONAL CHANGES TO HOURLY TEMPERATURE
TRENDS AS WELL AS SKY COVER. PERSISTENT STRATUS NORTH AND WEST OF
THE FORECAST AREA FROM EARLIER TODAY HAS DECREASED CONSIDERABLY IN
COVERAGE AREA...BUT STILL REMAINS IN A THIN STRIPE ACROSS CENTRAL
OHIO AND MORE EXTENSIVELY ALONG THE NEW YORK/PENNSYLVANIA BORDER.
ALTHOUGH THE NORTHERN PORTION OF THESE CLOUDS COULD STILL REMAIN
NORTH OF THE FORECAST AREA...THE STRATUS IS NOW MOVING VERY SLOWLY
INTO COSHOCTON COUNTY. THE HRRR REMAINS THE ONLY MODEL THAT
RECOGNIZES THESE CLOUDS...EVEN THE 00Z NAM THINKS SKIES ARE
CLEAR...AND SO HAVE BLENDED THE HRRR SKY COVER HEAVILY INTO THE
FORECAST. THIS BRINGS CLOUDS INTO THE REST OF EASTERN OHIO...BUT
HAVE STILL GONE WITH A CLEARING TREND BY SUNRISE. WINDS SHOULD BE
CALM OR NEARLY CALM TONIGHT...AND THE CLEAR SKIES OUTSIDE OF OHIO
WILL ALLOW FOR FULL RADIATIONAL COOLING. OVERNIGHT LOW
TEMPERATURES WERE GENERALLY UNCHANGED...EXCEPT FOR LOCATIONS
NORTH AND EAST OF PITTSBURGH WHICH WERE ALREADY 3-4 DEGREES BELOW
THE EXPECTED HOURLY TRENDS.
&&
.SHORT TERM /6 AM SATURDAY MORNING THROUGH MONDAY/...
CLEAR AND DRY CONDITIONS WILL PERSIST THROUGH THE WEEKEND AS HIGH
PRESSURE SETTLES OVERHEAD. ALTHOUGH THERE WILL BE LITTLE
MIXING...ABUNDANT SUNSHINE AND WARMING MID LEVELS SHOULD SUPPORT
ABOVE NORMAL DAYTIME TEMPERATURES. NIGHTTIME TEMPERATURES
HOWEVER...SHOULD REMAIN NEAR NORMAL WITH STRONG RADIATIONAL
COOLING EXPECTED.
ON MONDAY...THE APPROACH OF AN UPPER TROUGH WILL BRING AN INCREASE
IN CLOUD COVER AND COOLER TEMPERATURES HOWEVER MOST OF THE
MOISTURE AND LIFT WILL REMAIN SOUTH...SO LOW CHANCE POPS WERE
CARRIED THROUGH THE END OF THE PERIOD.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
BLEND OF MODELS CONSISTENT IN MOVING LOW PRESSURE SOUTH AND EAST
OF REGION THROUGH TUESDAY KEEPING CLOUDS ACROSS THE REGION.
GENERAL ZONAL FLOW ALOFT WILL KEEP TEMPERATURES MILD THROUGH THE
EXTENDED PERIOD. HARD TO TIME SHORTWAVES IN FAST FLOW MAY BRING
A LOW CHANCE FOR SHOWERS LATE WEEK.
&&
.AVIATION /04Z SATURDAY THROUGH WEDNESDAY/...
LIGHT WINDS AND STRONG RADIATIONAL COOLING OVERNIGHT WILL RESULT
IN PATCHY FOG DEVELOPING OVERNIGHT...LASTING THROUGH MID-MORNING.
MVFR VISIBILITY RESTRICTIONS ARE LIKELY...WITH IFR POSSIBLE BY
EARLY MORNING.
.OUTLOOK...SATURDAY NIGHT THROUGH WEDNESDAY/...
VFR CONDITIONS THROUGH THE PERIOD.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
916 PM EST FRI DEC 4 2015
.SYNOPSIS...
RIDGE OF HIGH PRESSURE WILL BRING DRY WEATHER AND SLOWLY
MODERATING TEMPERATURES THROUGH THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
WITH 915PM UPDATE...MADE ADDITIONAL CHANGES TO HOURLY TEMPERATURE
TRENDS AS WELL AS SKY COVER. PERSISTENT STRATUS NORTH AND WEST OF
THE FORECAST AREA FROM EARLIER TODAY HAS DECREASED CONSIDERABLY IN
COVERAGE AREA...BUT STILL REMAINS IN A THIN STRIPE ACROSS CENTRAL
OHIO AND MORE EXTENSIVELY ALONG THE NEW YORK/PENNSYLVANIA BORDER.
ALTHOUGH THE NORTHERN PORTION OF THESE CLOUDS COULD STILL REMAIN
NORTH OF THE FORECAST AREA...THE STRATUS IS NOW MOVING VERY SLOWLY
INTO COSHOCTON COUNTY. THE HRRR REMAINS THE ONLY MODEL THAT
RECOGNIZES THESE CLOUDS...EVEN THE 00Z NAM THINKS SKIES ARE
CLEAR...AND SO HAVE BLENDED THE HRRR SKY COVER HEAVILY INTO THE
FORECAST. THIS BRINGS CLOUDS INTO THE REST OF EASTERN OHIO...BUT
HAVE STILL GONE WITH A CLEARING TREND BY SUNRISE. WINDS SHOULD BE
CALM OR NEARLY CALM TONIGHT...AND THE CLEAR SKIES OUTSIDE OF OHIO
WILL ALLOW FOR FULL RADIATIONAL COOLING. OVERNIGHT LOW
TEMPERATURES WERE GENERALLY UNCHANGED...EXCEPT FOR LOCATIONS
NORTH AND EAST OF PITTSBURGH WHICH WERE ALREADY 3-4 DEGREES BELOW
THE EXPECTED HOURLY TRENDS.
&&
.SHORT TERM /6 AM SATURDAY MORNING THROUGH MONDAY/...
CLEAR AND DRY CONDITIONS WILL PERSIST THROUGH THE WEEKEND AS HIGH
PRESSURE SETTLES OVERHEAD. ALTHOUGH THERE WILL BE LITTLE
MIXING...ABUNDANT SUNSHINE AND WARMING MID LEVELS SHOULD SUPPORT
ABOVE NORMAL DAYTIME TEMPERATURES. NIGHTTIME TEMPERATURES
HOWEVER...SHOULD REMAIN NEAR NORMAL WITH STRONG RADIATIONAL
COOLING EXPECTED.
ON MONDAY...THE APPROACH OF AN UPPER TROUGH WILL BRING AN INCREASE
IN CLOUD COVER AND COOLER TEMPERATURES HOWEVER MOST OF THE
MOISTURE AND LIFT WILL REMAIN SOUTH...SO LOW CHANCE POPS WERE
CARRIED THROUGH THE END OF THE PERIOD.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
BLEND OF MODELS CONSISTENT IN MOVING LOW PRESSURE SOUTH AND EAST
OF REGION THROUGH TUESDAY KEEPING CLOUDS ACROSS THE REGION.
GENERAL ZONAL FLOW ALOFT WILL KEEP TEMPERATURES MILD THROUGH THE
EXTENDED PERIOD. HARD TO TIME SHORTWAVES IN FAST FLOW MAY BRING
A LOW CHANCE FOR SHOWERS LATE WEEK.
&&
.AVIATION /02Z SATURDAY THROUGH WEDNESDAY/...
VFR CONDITIONS THROUGH THE EVENING. LIGHT WINDS AND STRONG
RADIATIONAL COOLING OVERNIGHT MAY LEAD TO PATCHY MVFR FOG
DEVELOPING EARLY IN THE MORNING...BURNING OFF BY MID-MORNING.
.OUTLOOK...SATURDAY NIGHT THROUGH WEDNESDAY/...
VFR CONDITIONS THROUGH THE PERIOD.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
648 PM EST FRI DEC 4 2015
.SYNOPSIS...
RIDGE OF HIGH PRESSURE WILL BRING DRY WEATHER AND SLOWLY
MODERATING TEMPERATURES THROUGH THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
WITH 530PM UPDATE...UPDATED HOURLY TEMPERATURE TRENDS AS WELL AS
SKY COVER. AS THE PREVIOUS DISCUSSION ALREADY MENTIONED...STRATUS
REMAINS OVER OHIO AND PENNSYLVANIA...BUT JUST OUTSIDE OF THE
FORECAST AREA. ALTHOUGH THE HRRR SHOWS THE STRATUS MOVING INTO THE
REGION AS IT CONTINUES TO BURN OFF...IT IS ALSO THE ONLY MODEL
THAT DEPICTS THE CLOUDS...SOMETHING THE OTHER MODELS ARE CLEARLY
FAILING ON. ESSENTIALLY WILL CONTINUE WITH THE PERSISTENCE
FORECAST. PREVIOUS DISCUSSION FOLLOWS.
MAINLY CLEAR SKIES ARE ANTICIPATED OVERNIGHT AS RIDGE OF HIGH
PRESSURE MOVES OVER THE REGION. THE HRRR MODEL SUGGESTS THAT
REMAINING STRATUS OVER OHIO THAT DOESN`T BURN OFF THIS AFTERNOON
MAY MOVE OVER THE REGION...BUT NOT CONFIDENT THAT THIS IS
REALISTIC SINCE THE BACK EDGE IS BURNING OFF RATHER QUICKLY. WITH
THIS IN MIND...EXPECT RADIATIONAL COOLING TO SUPPORT TEMPERATURES
IN THE 20`S CWA-WIDE.
&&
.SHORT TERM /6 AM SATURDAY MORNING THROUGH MONDAY/...
CLEAR AND DRY CONDITIONS WILL PERSIST THROUGH THE WEEKEND AS HIGH
PRESSURE SETTLES OVERHEAD. ALTHOUGH THERE WILL BE LITTLE
MIXING...ABUNDANT SUNSHINE AND WARMING MID LEVELS SHOULD SUPPORT
ABOVE NORMAL DAYTIME TEMPERATURES. NIGHTTIME TEMPERATURES
HOWEVER...SHOULD REMAIN NEAR NORMAL WITH STRONG RADIATIONAL
COOLING EXPECTED.
ON MONDAY...THE APPROACH OF AN UPPER TROUGH WILL BRING AN INCREASE
IN CLOUD COVER AND COOLER TEMPERATURES HOWEVER MOST OF THE
MOISTURE AND LIFT WILL REMAIN SOUTH...SO LOW CHANCE POPS WERE
CARRIED THROUGH THE END OF THE PERIOD.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
BLEND OF MODELS CONSISTENT IN MOVING LOW PRESSURE SOUTH AND EAST
OF REGION THROUGH TUESDAY KEEPING CLOUDS ACROSS THE REGION.
GENERAL ZONAL FLOW ALOFT WILL KEEP TEMPERATURES MILD THROUGH THE
EXTENDED PERIOD. HARD TO TIME SHORTWAVES IN FAST FLOW MAY BRING
A LOW CHANCE FOR SHOWERS LATE WEEK.
&&
.AVIATION /00Z SATURDAY THROUGH WEDNESDAY/...
VFR CONDITIONS THROUGH THE EVENING. LIGHT WINDS AND STRONG
RADIATIONAL COOLING OVERNIGHT MAY LEAD TO PATCHY MVFR FOG
DEVELOPING EARLY IN THE MORNING...BURNING OFF BY MID-MORNING.
.OUTLOOK...SATURDAY THROUGH WEDNESDAY/...
VFR CONDITIONS THROUGH THE PERIOD.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
1001 PM EST FRI DEC 4 2015
.UPDATE...
REMNANT VERY LOW STRATUS DECK LODGED WITHIN THE BACKGROUND OF WEAK
SURFACE RIDGING NOW ENCOMPASSING MUCH OF INDIANA BEGINNING A MORE
PROGRESSIVE OUTWARD EXPANSION AS NOCTURNAL COOLING STRENGTHENS. 1000-
975 MB RH FIELDS ON BOTH THE HRRR AND RAP CONCUR WITH BOTH THE
CURRENT PLACEMENT OF THIS CLOUD DECK AND THE EVENTUAL NORTHEAST
MOVEMENT TOWARD THE FORECAST AREA OVERNIGHT. THESE TRENDS WOULD
POINT TOWARD TAKING A DECIDELY MORE PESSIMISTIC OUTLOOK ON CLOUD
COVER NEARLY AREAWIDE FOR THE EARLY-MID MORNING PERIOD. ELEMENT OF
SHALLOW FOG WITHIN THIS NEAR SURFACE MOISTURE PLUME AS WELL. COOLING
PROCESS MAKING THE MOST OF THIS LONG DURATION OF OPEN SKY EARLY
TONIGHT...SOME LOCALES ALREADY DOWN INTO THE LOWER 30S. OVERALL LOW
TEMPERATURE FORECAST IN LINE WITH CURRENT TRENDS...SOME REALIGNMENT
OF THE TEMPERATURE CURVE GOING FORWARD BASED ON EXPECTATIONS FOR
CLOUD COVER TO EVENTUALLY CAP THIS COOLING /PARTICULARLY SOUTHWEST
SECTIONS/.
&&
.AVIATION...ISSUED 628 PM EST FRI DEC 4 2015
DEEP LAYER DRY/STABLE CONDITIONS WILL FAVOR A CLEAR SKY THROUGH THE
EARLY PORTION OF TONIGHT. FOG AND/OR VERY LOW STRATUS WILL THEN
BECOME A CONCERN DURING THE EARLY MORNING PERIOD. A DIMINISHING
SOUTHWEST GRADIENT AND HIGHER NEAR SURFACE MOISTURE CONTENT WILL
FAVOR SOME DEGREE OF FOG DEVELOPMENT DURING THIS TIME. THE
POTENTIAL ALSO EXISTS FOR THE LINGERING CANOPY OF IFR STRATUS
LOOMING ACROSS NORTH-CENTRAL INDIANA TO EXPAND NORTHEASTWARD
OVERNIGHT UNDER THE PREVAILING SW FLOW. HIGHER PROBABILITY EXISTS
FOR THE FOG COMPONENT TO EMERGE GIVEN A SURFACE BASED INVERSION...AND
WILL CONTINUE TO FAVOR A PERIOD OF IFR/MVFR VSBY RESTRICTIONS DURING
THE MORNING PERIOD. PLAUSIBLE SCENARIO DOES EXIST FOR A STRONGER
RESPONSE RESULTING IN LIFR CONDITIONS IN FOG AND/OR STRATUS AT ONE
OR MORE TERMINALS. GIVEN VERY LOW CONFIDENCE ON THIS POSSIBILITY
AND THE LACK OF OBSERVATIONAL EVIDENCE AT THIS STAGE...WILL REFRAIN
FROM MOVING TOWARD A MORE AGGRESSIVE REDUCTION BELOW IFR AT THIS
TIME.
FOR DTW...EXISTING CLEAR SKY AND DIMINISHING SW FLOW WILL FAVOR FOG
DEVELOPMENT DURING THE EARLY MORNING PERIOD. ENVIRONMENT FAVORS
MVFR/IFR RESTRICTIONS...ALTHOUGH THE POTENTIAL FOR A PERIOD OF LIFR
WILL EXIST. IN ADDITION...WILL CLOSELY MONITOR EXISTING IFR STRATUS
OVER INDIANA...WHICH MAY TEND TO ADVANCE BACK NORTHEAST ONCE GREATER
NOCTURNAL TAKES HOLD.
//DTW THRESHOLD PROBABILITIES...
* LOW CONFIDENCE IN CEILINGS FALLING BELOW 5000 FT LATE
TONIGHT/EARLY SATURDAY.
* LOW CONFIDENCE FOR CIGS/VSBY FALLING BELOW 200 FT AND/OR
1/2SM 10-14Z.
&&
.PREV DISCUSSION...ISSUED 318 PM EST FRI DEC 4 2015
DISCUSSION...
THE MAIN WEATHER NARRATIVE REMAINS THE EXTENDED RUN INTO NEXT
WEEKEND...OF ABOVE NORMAL TEMPERATURES...A HIGH AMOUNT OF SUNSHINE
FOR DECEMBER...AND THE PREDOMINATELY DRY CONDITIONS.
DECISIVE CLEARING CAME TO FRUITION THIS MORNING ON THE BACKS OF VERY
ACTIVE SUBSIDENCE IN THE 925-700MB LAYER. THIS FRESH ROUND OF
SUBSIDENCE OCCURRED ALONG THE SOUTHERN PERIPHERY OR IN THE ZONE OF AVA
BEHIND A SHORTWAVE THAT CUT THROUGH THE GREAT LAKES LAST NIGHT. FOR
TONIGHT...MODELED MOISTURE PROFILES MAINTAIN HIGHER AMBIENT MOISTURE
IN THE BOUNDARY LAYER WHICH INTRODUCES SOME UNCERTAINTY. WITH THAT
STATED...OVERALL THERMODYNAMIC STRUCTURE AND STEADY LOWERING OF THE
INVERSION BASE DURING THE NEXT 12 TO 36 HOURS SUGGESTS THAT NOW THAT
CLOUDS HAVE BROKEN IT WILL BE DIFFICULT TO DEVELOP NEW CLOUD.
INSTEAD...THE POTENTIAL DOES EXIST FOR CLOUD TO THE SOUTH TO EXPAND
IN COVERAGE BACK NORTHWARD POSSIBLY IMPACTING AREAS SOUTH OF M 59
LATER TONIGHT. DUE TO THE INVERSION STRUCTURE...FORECASTER
PREFERENCE IS SIDED TO POTENTIAL FOG DEVELOPMENT LATE TONIGHT RATHER
THAN STRATUS. WITH THIS IN MIND THE BETTER POTENTIAL REMAINS ACROSS
THE SOUTHERN CWA AND INTO ST CLAIR COUNTY WHERE THE BOUNDARY LAYER
GRADIENT WINDS WILL BE ALLOWED TO RELAX UNDER BETTER SURFACE HIGH
PRESSURE.
LESS IN THE WAY OF STRATUS/FOG IS EXPECTED TO BEGIN THE DAY SATURDAY
THAN THIS MORNING. THIS WILL SET THE STAGE FOR A WONDERFUL EARLY
DECEMBER SATURDAY ACROSS ALL OF SOUTHEASTERN MICHIGAN. THE BIG
QUESTION FOR SATURDAY IS WHAT WILL HIGH TEMPERATURES BE WITH A VERY
STRONG STABLE LAYER LOWERING AND SQUASHING MIXING HEIGHTS OVER THE
REGION. MODELS HAVE BEEN UNDERFORECASTING HIGHS A TOUCH THE PAST TWO
DAYS...AS A RESULT...INCREASED HIGHS INTO THE LOWER 50S MANY
AREAS...UPPER 40S NEAR THE WATER AND LOWER SURFACE PRESSURE
LOCATIONS. WITH AMOUNT OF GRADIENT FLOW THAT IS NORMALLY IN PLACE
THIS TIME OF YEAR...A PRETTY ATYPICAL FORECAST WITH THE INVERSION ON
THE GROUND. SUFFICE IT TO SAY WITH PARAMETERIZATIONS AND NEGLIGIBLE
VERTICAL RESOLUTION IN THE MODEL DATA...THERE ISN`T A WHOLE LOT OF
CONFIDENCE IN THE MAX TEMPERATURE GUIDANCE.
A SIZABLE MIDLEVEL SHORTWAVE AND PSEUDO CUTOFF IS FORECASTED TO
ARRIVE OVER THE CENTRAL GREAT LAKES BY LATE SUNDAY. WHILE MODELS
HAVE SOUTHEASTERN MICHIGAN ON THE FAVORABLE SIDE FOR MIDLEVEL
FORCING...PRIMARILY DEFORMATION...FORECAST DATA IS OVERWHELMINGLY IN
SUPPORT OF A MOISTURE STARVED SYSTEM. SUSPECT...HIGH CLOUD TO
INCREASE DURING THE DAY ON SUNDAY BUT NOT IN TIME TO CLASSIFY THE
DAY AS CLOUDY OR OVERCAST. HIGHS ON SUNDAY ARE AGAIN EXPECTED TO
REACH THE MIDDLE 40S.
QUIET EXTENDED PERIOD IS IN STORE FOR SOUTHEAST MICHIGAN. SURFACE
HIGH PRESSURE AND UPPER LEVEL RIDGING WILL REMAIN IN PLACE ACROSS
THE MIDWEST RESULTING IN DRY AND PLEASANT CONDITIONS. A SHORTWAVE
TROUGH PIVOTING THROUGH THE GREAT LAKES REGION ON WEDNESDAY NIGHT
WILL BRING THE NEXT CHANCE OF RAIN TO THE REGION. AT THIS TIME HAVE
ONLY INCLUDED A SLIGHT CHANCE /20 PERCENT/ FOR WEDNESDAY NIGHT INTO
THURSDAY. HIGH TEMPERATURES REMAIN IN THE MID TO UPPER 40S FROM
MONDAY THROUGH NEXT THURSDAY. LOW TEMPERATURES DROP INTO THE LOW TO
MID 30S OVERNIGHT.
MARINE...
SLOWLY WARMING SOUTH-SOUTHWEST FLOW PREDOMINATELY IN THE 10 TO 15
KNOT RANGE WILL BE IN PLACE THROUGH THE WEEKEND OVER THE CENTRAL
GREAT LAKES...LEADING TO STABLE PROFILES AND LOW WAVES. A FEW GUSTS
UP AROUND 20 KNOTS ARE EXPECTED ACROSS CENTRAL PORTIONS OF LAKE
HURON. HIGH PRESSURE WILL EXPAND BACK ACROSS THE GREAT LAKES EARLY
NEXT WEEK...PROVIDING LIGHT WINDS MONDAY INTO AT LEAST TUESDAY.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MICHIGAN WATERS OF LAKE ERIE...NONE.
&&
$$
UPDATE.......MR
AVIATION.....MR
DISCUSSION...CB/RK
MARINE.......SF
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
1151 PM EST WED DEC 2 2015
.AVIATION...
LINGERING WINDOW FOR LIGHT SNOW SHOWERS FROM PTK INTO THE DETROIT
CORRIDOR THROUGH 08Z BEFORE SUPPORTIVE ENVIRONMENT WANES
CONSIDERABLY. A MORE EXTENSIVE REGION OF LOW MVFR/IFR WILL ENCOMPASS
THIS CORRIDOR THROUGH MUCH OF THE EARLY MORNING PERIOD. A GRADUAL
IMPROVEMENT IN CEILING HEIGHTS FROM NORTH TO SOUTH DURING THE LATTER
HALF OF THE MORNING.
FOR DTW...WINDOW FOR LIGHT SNOW SHOWER DEVELOPMENT THROUGH 08Z.
AREA OBSERVATIONS PROVIDING INCREASING CONFIDENCE FOR A PERIOD OF
IFR...BOTH WITH THESE SNOW SHOWER AND IMMEDIATELY BEHIND THE
ACTIVITY.
//DTW THRESHOLD PROBABILITIES...
* HIGH FOR CEILING BELOW 5000 FT THROUGH THURSDAY MORNING...LOW
THURSDAY AFTERNOON.
* HIGH FOR PTYPE AS SNOW TONIGHT.
&&
.PREV DISCUSSION...ISSUED 757 PM EST WED DEC 2 2015
UPDATE...
NARROW STRIP OF FRONTAL FORCING ADVANCING OUT AHEAD OF THE INBOUND
UPPER WAVE EFFECTIVELY CAPITALIZING ON THE ONSET OF NOCTURNAL
COOLING POST-SUNSET AND THE ENSUING FAVORABLE REDUCTION IN
FREEZING LEVELS TO GENERATE A BURST OF ACCUMULATING SNOWFALL FROM
EASTERN LIVINGSTON COUNTY INTO WESTERN/CENTRAL OAKLAND AND
SOUTHERN GENESSEE COUNTY. UP TO AN INCH OF ACCUMULATION IN
LOCALIZED AREAS...BUT CONFINED TO NON-ROADWAY SURFACES GIVEN THE
STILL SUFFICIENTLY WARM AMBIENT ROAD TEMPS. RECENT RADAR TRENDS IN
SUPPORT OF LATEST HRRR GUIDANCE IN ALLOWING THIS MOISTURE AXIS TO
STEADILY WEAKEN WITH TIME OVER THE NEXT 1-2 HOURS...EXISTING MID
LEVEL ASCENT REPOSITIONING TO THE SOUTH/WEST CLOSER TO THE UPPER
LOW. WINDOW FOR ADDITIONAL LIGHT SNOW SHOWERS THROUGH ROUGHLY 07-
08Z SOUTH OF THE M-59 CORRIDOR AS MID LEVEL DEFORMATION ALONG THE
NORTHERN PERIPHERY OF THIS SYSTEM PIVOTS THROUGH. ANY ADDITIONAL
ACCUMULATION MINOR.
PREV DISCUSSION...ISSUED 301 PM EST WED DEC 2 2015
DISCUSSION...
A BAND OF LIGHT TO MODERATE SNOW ORIENTED ALONG A SURFACE BOUNDARY
EXTENDING FROM A LOW WEAKLY COUPLED TO LAKE MICHIGAN CONTINUES TO
ROTATE NORTHWARD INTO THE CWA THIS AFTERNOON. WARM BOUNDARY LAYER
TEMPERATURES ENSURE RAIN IN THE LIGHTEST PRECIPITATION, BUT UPSTREAM
OBSERVATIONS CONFIRM THE COLUMN HAS POTENTIAL FOR SNOW IN HIGHER
REFLECTIVITY. THIS BAND IS BEING DRIVEN BY SHALLOW MODERATE FGEN
THAT IS REALLY CAPITALIZING ON WEAK STATIC STABILITY THROUGH THE
LOWEST 700MB. IN FACT, SOME CONDITIONAL INSTABILITY IS EVEN NOTED ON
MODEL CROSS-SECTIONS. AFTER SLOWLY DRIFTING SOUTH, THE PARENT UPPER
LOW HAS FINALLY BEGUN TO PULL EAST. THIS WILL RESULT IN LOW PRESSURE
RELEASING FROM LAKE MICHIGAN AND THE BETTER FORCING RIPPLING EAST
ACROSS THE AREA BETWEEN 21-02Z. BRIEF HEAVIER SNOW RATES WILL BE
POSSIBLE WITH AROUND AN INCH OF ACCUMULATION POSSIBLE. A LOCALIZED
2" AMOUNT IS NOT OUT OF THE QUESTION, BUT APPEARS UNLIKELY ATTM.
A SECONDARY FOCUS OF SNOW SHOWERS IS CENTERED OVER THE CHICAGO AREA
AND IS TIED TO A PV ANOMALY EMBEDDED WITHIN CYCLONIC FLOW ALOFT.
THIS CORRIDOR OF FORCING WILL PIVOT WELL SOUTHEAST OF THE AREA.
HOWEVER, AS NW FLOW FILLS IN BEHIND DEPARTING LOW PRESSURE, AN
INCREASE IN DEFORMATION FORCING COMBINED WITH A BRIEF WINDOW FOR
SOME MOISTURE ENHANCEMENT OFF OF LAKE MICHIGAN COULD ALLOW LIGHT
SNOW TO HANG ON AS LATE AS MIDNIGHT. ACCUMS WILL REMAIN QUITE LIGHT
AND CONFINED TO LOCATIONS SOUTH OF 8 MILE.
LOW PRESSURE IN THE GULF OF ALASKA WILL OPEN UP OVER THE NEXT 24
HOURS AND PROPAGATE EAST IN ADVANCE OF INCREASINGLY ENERGETIC UPPER-
LEVEL FLOW OVER THE PACIFIC. THIS WILL FORCE ANOTHER WAVE OF RIDGING
ACROSS THE GREAT LAKES FOR THE END OF THE WEEK. INITIALLY, CLOUDS
WILL BE SLOW TO EXIT DUE TO THE SLOW MOVING UPPER LOW ON THURSDAY,
BUT TEMPERATURES WILL REBOUND INTO THE MID TO UPPER 40S ON FRIDAY.
BY SATURDAY MORNING, 500MB HEIGHT WILL BE APPROACHING THE ALL-TIME
DECEMBER RECORD OF 580.5DM, THOUGH IT IS PRESENTLY MODELED TO FALL
JUST SHORT.
DRY AND QUIET CONDITIONS WILL BE THE STORY THIS WEEKEND INTO THE
BEGINNING OF NEXT WEEK AS UPPER LEVEL RIDGING HOLDS OVER SOUTHEAST
MICHIGAN. TROUGHING TRIES TO MOVE IN TOWARDS THE END OF THE
WEEKEND...HOWEVER RIDGING REMAINS STRONG WHICH WILL LEAVE THE AREA
DRY. TEMPERATURES DURING THIS PERIOD WILL REMAIN SLIGHTLY ABOVE
NORMAL AS HIGHS RUN IN 40 DEGREE RANGE WITH LOWS IN THE 30S.
MARINE...
A TROUGH OF LOW PRESSURE WILL PUSH ACROSS FAR SOUTHEASTERN MICHIGAN
THIS EVENING SUPPORTING A LIGHT AND VARIABLE WIND THIS EVENING. WIND
DIRECTIONS ARE THEN EXPECTED TO RESPOND OUT OF THE NORTH BY LATE
TONIGHT AS THE SURFACE TROUGH STRIPS OUT. WINDS ARE FORECASTED TO
INCREASE MODESTLY ON THURSDAY WITH NORTHWESTERLY WINDS RANGING
BETWEEN 10 AND 20 KNOTS PARTICULARLY OVER LAKE HURON. A BRIEF PERIOD
OF STRONG SOUTHWESTERLY WINDS IS EXPECTED TO DEVELOP OVER THE
CENTRAL GREAT LAKES LATE THURSDAY NIGHT OR EARLY FRIDAY. SOUTHWEST
WINDS ON SAGINAW BAY AND THE CENTRAL LAKE HURON BASIN MAY GUST
BETWEEN 20 AND 30 KNOTS. OTHERWISE HIGH PRESSURE IS EXPECTED TO KEEP
CONDITIONS QUIET DURING THE NEXT WEEK.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MICHIGAN WATERS OF LAKE ERIE...NONE.
&&
$$
AVIATION.....MR
UPDATE.......MR
DISCUSSION...JVC/SS
MARINE.......CB
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
604 PM CST FRI DEC 4 2015
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 323 PM CST FRI DEC 4 2015
SOUTHWEST FLOW WILL CONTINUE TO BRING SEASONABLY WARM
TEMPERATURES ACROSS THE UPPER MIDWEST. THE MAIN CONCERN IS THE
WIND POTENTIAL ON THE LEE SIDE OF THE BUFFALO RIDGE ACROSS FAR
WESTERN MN. A FEW OF THE HIRES MODELS SHOW GUST NEAR 50KTS...BUT
THOSE MODELS ARE CURRENTLY OVER DOING THE WINDS ACROSS THE
DAKOTAS. BUFR SOUNDINGS OFF THE RAP AND HRRR KEEP THE WINDS ABOVE
THE BOUNDARY LAYER. WITH THAT SAID...COULD SEE 35-40KT GUSTS LATE
TONIGHT AS WINDS CROSS THE RIDGE...AND MAY NEED A WIND HEADLINE
TONIGHT FOR YELLOW MEDICINE OR LAC QUI PARLE COUNTIES IF THE WINDS
ARE ABLE TO BREAK THROUGH THE INVERSION DOWN TO THE SURFACE.
CONFIDENCE WAS TOO LOW TO ISSUE ONE AT THIS TIME.
A NARROW LONG WAVE TROUGH WILL APPROACH THE REGION FROM THE WEST
LATE SATURDAY. EXPECT CLOUDS TO INCREASE IN RESPONSE TO THIS
WAVE...AND FORECAST SOUNDINGS SHOW SOME DRIZZLE/SPRINKLES POSSIBLE
AS WELL. SATURDAYS TEMPS WILL BE SIMILAR TO TODAY...WITH MID 40S
COMMON ACROSS THOSE AREAS THAT DO NOT HAVE SNOW COVER.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 323 PM CST FRI DEC 4 2015
CONTINUANCE OF ABOVE NORMAL TEMPERATURES AND DRY WEATHER WILL
DESCRIBE THE BULK OF THE LONG TERM PERIOD.
TO START OFF THE PERIOD HOWEVER...A WEAK COLD FRONT WILL BE
TRACKING ACROSS THE AREA ON SATURDAY NIGHT. ASSOCIATED MOISTURE
AND FORCING ARE NEGLIGIBLE...SO EXPECT ANY RESULTANT PRECIP TO BE
MOSTLY IN THE FORM OF DRIZZLE. ABSENCE OF MOISTURE IN THE
DENDRITIC LAYER SHOULD MEAN THE PRECIP WILL BE OF THE LIQUID
VARIETY.
SUNDAY INTO THE UPCOMING WEEK FEATURES THE PERSISTENCE OF MID
LEVEL RIDGING...WITH TEMPERATURES AVERAGING 12-18 DEGREES ABOVE
CLIMATOLOGICAL NORMALS.
WHILE THE MAJORITY OF NEXT WEEK LOOKS DRY AND WARM...THE RIDGE
DOES LOOK TO BREAK DOWN LATE IN THE WEEK. THERE ARE STILL NOTABLE
DIFFERENCES BETWEEN THE GFS AND ECMWF...BUT THERE WOULD LIKELY BE
ANOTHER UPTICK IN TEMPERATURES AHEAD OF THE SYSTEM TOWARD THE END
OF THE WEEK FOLLOWED BY RAIN/SNOW CHANCES FRIDAY.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 551 PM CST FRI DEC 4 2015
A COUPLE CONCERNS IN THIS TAF PERIOD ARE THE INCREASING LOW LEVEL
WINDS TONIGHT THAT SHOULD APPROACH 60KTS BETWEEN 1500-2000FT AND
THE DEVELOPMENT AND ADVANCEMENT OF LOW STRATUS CLOUDS AND MVFR
CEILINGS OVER THE NEXT 24 HOURS. FIRST...THE WINDS ARE ALREADY
INCREASING ACROSS THE AREA. OUR BALLOON LAUNCH IN CHANHASSEN MN
THIS EVENING HAD 40KTS AT 1200FT...AND THIS SHOULD CONTINUE TO
INCREASE TONIGHT. THEREFORE...WE HAVE CONTINUED THE LOW LEVEL WIND
SHEAR IN THE TAF AT ALL THE TAF SITES. SECOND...WE HAVE PUSHED
BACK THE ONSET OF THE LOW CEILINGS...ESPECIALLY FOR THE TAF SITES
IN EASTERN MN AND WESTERN WI. THE CLOUDS HAVE YET TO DEVELOP IN
THE DAKOTAS...SO WE THINK MUCH OF THE MODEL GUIDANCE IS A BIT
AGGRESSIVE IN MOVING THESE CLOUDS TO THE EAST ACROSS MN. OUTSIDE
OF KAXN AND KRWF...THE MVFR CLOUD DECK WILL BE MORE OF AN ISSUE
FOR TOMORROW AFTERNOON.
KMSP...
NOT MUCH TO ADD TO THE DISCUSSION ABOVE. OUTSIDE OF SOME BUMPS IN
THE LOWEST COUPLE THOUSAND FEET DUE TO STRONG WINDS...LOOKS LIKE
MOSTLY CLEAR SKIES THROUGH TOMORROW MORNING.
/OUTLOOK FOR KMSP/
SUN...VFR. LINGERING MVFR IN THE MORNING. WINDS W 5 KTS.
MON...VFR. WINDS S 10 KTS.
TUE...MVFR POSSIBLE. WINDS W SW 5-10 KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
&&
$$
SHORT TERM...JRB
LONG TERM...LS
AVIATION...CLF
AREA FORECAST DISCUSSION...UPDATED
NWS ST LOUIS MO
824 PM CST FRI DEC 4 2015
.UPDATE:
Issued at 824 PM CST Fri Dec 4 2015
Have issued a dense fog advisory for the eastern counties as an
area of dense fog is spreading westward this evening now that the
boundary layer is becoming saturated after sunset. Visibilities
are already down to 3SM at Salem and are 1/4SM at Effingham and
Taylorville. Visibility guidance from the RAP and experimental
HRRR suggests that the dense fog may spread back to the
Mississippi river overnight, so may need to expand the advisory
again this evening. Where there are temperatures below freezing,
the fog may deposit some icing on roads which could produce some
slick spots. Rest of the forecast still looks on track.
Britt
&&
.SHORT TERM: (Through Late Tonight)
Issued at 321 PM CST Fri Dec 4 2015
Late this afternoon, an area of fog/stratus was located over
IL/IN near the center of a surface high. Some models show the
existing fog/stratus backbuilding overnight, especially an
expansion into southwest IL. This scenario does not seem
unreasonable given the presence of fog/stratus last night, the
observed slow erosion of fog/stratus today, moisture trapped
beneath an inversion noted on BUFKIT soundings, and the expected
wx conditions tonight (particularly the light winds and initially
clear skies over the eastern CWA which will promote radiational
cooling). If it develops, the thickest fog/stratus would be
expected over southwest and southern IL. Farther west, southerly
surface winds should remain strong enough to interfere with
widespread fog formation, although patchy fog cannot be ruled
out, especially with any breaks in the approaching cirrus
associated with a weak disturbance.
Kanofsky
.LONG TERM: (Saturday through Next Friday)
Issued at 321 PM CST Fri Dec 4 2015
The warming trend noted today (temperatures in the 50s by 21z)
will continue tomorrow. A stronger vort max then approaches the
region tomorrow night and could bring some light rain to the area
on Sunday, but moisture remains limited. This forecast maintains
fairly low PoPs for Sunday due to the limited moisture. The
latest model runs are in better agreement with a more progressive
solution, and most models have the upper vort center well east of
the area by 12z Mon. Persistent southerly to southwesterly flow
will help temperatures rebound into the mid-upper 50s during the
middle and late part of the week. A few other disturbances are
forecast to move across the central CONUS during the middle and
late part of next week, possibly bringing light pcpn to MO/IL.
Kanofsky
&&
.AVIATION: (For the 00z TAFs through 00z Saturday Evening)
Issued at 535 PM CST Fri Dec 4 2015
For COU/UIN...SE to SSE winds are expected to continue thru the
TAF period below 10 kts.
Specifics for KSTL/KSUS/KCPS: Main question for tonight will be
occurrence and/or timing of FG or stratus development. Latest
guidance continues to suggest FG developing around 06z and
persisting thru sunrise. Given dewpoints aob 32 degrees across the
region, icing will be an issue if FG develops. Given the sfc winds
are still sely around 7 kts, stratus may be more likely. Will
continue to monitor and update as needed.
Tilly
&&
.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...Dense Fog Advisory until noon CST Saturday FOR Bond IL-Clinton
IL-Fayette IL-Marion IL-Montgomery IL-Washington IL.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1125 PM CST WED DEC 2 2015
.UPDATE...
ISSUED AT 1125 PM CST WED DEC 2 2015
PATCHY FOG HAS BEEN WITHDRAWN FROM THE FCST. SVRL SITES HAVE
DROPPED PAST THEIR CROSS-OVER TEMPS BY SVRL DEGS AND NO FOG HAS
FORMED. IF IT HASN`T BY NOW...I DON`T BELIEVE IT WILL. THE NAM
AND HRRR NOW HAVE NO FOG.
BELIEVE THE MODELS FCSTG FOG ARE DO SO DUE TO PROBLEMS MODELING
THE BL WITH SNOW ON THE GROUND. THE NAM AND SREF HAVE STRONG
SIGNALS FOR FOG DEVELOPMENT THU NIGHT...BUT THIS IS PROBABLY IN
ERROR. WE WILL RE-EVALUATE LATER IN THIS SHIFT.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 315 PM CST WED DEC 2 2015
QUIET WEATHER IS ANTICIPATED THROUGH THE SHORT TERM PERIODS AS
HEIGHTS CONTINUE TO INCREASE ALOFT IN RESPONSE TO AN AREA OF HIGH
PRESSURE BUILDING ACROSS THE INTERMOUNTAIN WEST. EXPECT A WEAK
SHORTWAVE...EVIDENT ACROSS THE NORTHERN ROCKIES...TO APPROACH THE
LOCAL AREA ON THURSDAY...BUT LACKING SIGNIFICANT MOISTURE...LITTLE
MORE THAN SOME PASSING MID LEVEL CLOUDS ARE EXPECTED DURING THE
DAYTIME HOURS TOMORROW.
OTHERWISE...SEASONABLY WARM TEMPERATURES THIS AFTERNOON WILL DROP
OFF RAPIDLY THIS EVENING...AS WITH CLEAR SKIES AND MAINLY LIGHT
WINDS...TEMPERATURES ARE ANTICIPATED TO FALL RAPIDLY AFTER SUNSET.
WITH THESE CLEAR SKIES...LIGHT WINDS...AND SOME LOW LEVEL MOISTURE
FROM MELTING SNOW THIS AFTERNOON...EXPECT THE POSSIBILITY FOR SOME
PATCHY GROUND FOG DURING THE EARLY MORNING HOURS TOMORROW. WHILE
THE SREF PROBS ARE ONLY AROUND 40 PERCENT FOR FOG DEVELOPMENT
OVERNIGHT...THE NAM IS INDICATING THE POTENTIAL FOR MORE
WIDESPREAD FOG...ESPECIALLY ACROSS THE SOUTHERN HALF OF THE
CWA...SO WENT WITH A COMPROMISE MENTIONING PATCHY FOG GENERALLY
FROM THE TRI-CITIES SOUTH. WHILE THE NAM IS LIKELY WAY TOO
OVERDONE WITH FOG POTENTIAL AND LIGHT WESTERLY COMPONENT TO WIND
IS NOT FAVORABLE FOR FOG DEVELOPMENT...COULD NOT COMPLETELY IGNORE
THE POTENTIAL GIVEN THE GOOD RADIATIONAL CONDITIONS ANTICIPATED.
FOR THURSDAY...A FAIRLY NICE DECEMBER DAY IS ANTICIPATED ACROSS
THE REGION AS WITH MAINLY CLOUD FREE SKIES AND A MILD AIRMASS IN
PLACE...EXPECT AFTERNOON TEMPERATURES TO REBOUND FROM THE
CHILLY...YET SEASONABLE START TO THE DAY...EVENTUALLY CLIMBING 10
OR SO DEGREES ABOVE SEASONAL NORMS BY AFTERNOON.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 315 PM CST WED DEC 2 2015
THE LONG TERM FORECAST REMAINS FAIRLY QUIET WITH VERY LITTLE
PRECIPITATION CHANCES TO SPEAK OF AND MILD TEMPERATURES RETURNING
TO THE FORECAST AREA. THE OVERALL SETUP HAS A SURFACE RIDGE
BUILDING ACROSS THE PLAINS BY THE END OF THE WEEK. A SURFACE
TROUGH WILL DEVELOP ACROSS THE FRONT RANGE BRINGING RETURN FLOW
AND WARM AIR ADVECTION TO THE REGION.
THERE IS A CONCERN FOR FOG POTENTIAL BOTH FRIDAY MORNING AND
SATURDAY MORNING AS THE NAM IS REALLY HITTING THIS HARD IN BOTH
GUIDANCE AND GENERAL OUTPUT. HOWEVER...THE NAM IS ALSO BIASED BY
THE AMOUNT OF SNOW COVER IT THINKS IS STILL ON THE GROUND. THE GFS
SUGGESTS WE WILL HAVE STRONGER WINDS IN THE RETURN FLOW AND THUS
LIMITING FOG POTENTIAL. FOR NOW WENT AHEAD AND LEFT MENTION OUT OF
THE FORECAST BUT THIS WILL NEED TO BE LOOKED AT CLOSER IN FUTURE
SHIFTS.
THE TROUGH AXIS WILL PUSH THROUGH THE REGION SATURDAY NIGHT BUT
IS NOT EXPECTED TO HAVE MUCH OF AN AFFECT ON THE AREA.
TEMPERATURES WILL DIP SLIGHTLY AND SLIGHT PRECIPITATION CHANCES
REALLY START TO DEVELOP SATURDAY NIGHT ACROSS THE SOUTHEAST AS THE
SYSTEM EXITS THE AREA.
A FEW WAVES WILL PASS BY THE REGION...BUT AT THE CURRENT TIME DO
NOT SEEM TO BE BIG WEATHER MAKERS FOR THE PLAINS. TEMPERATURES
WILL REMAIN SLIGHTLY ABOVE NORMAL FOR THE REMAINDER OF THE LONG
TERM.
&&
.AVIATION...(FOR THE 06Z KGRI/KEAR TAFS THROUGH 06Z THU NIGHT)
ISSUED AT 1125 PM CST WED DEC 2 2015
REST OF TONIGHT: VFR SKC. LIGHT W WINDS UNDER 5 KTS. CONFIDENCE:
HIGH
THU: VFR WITH A FEW SHREDS OF 25K FT CIRROSTRATUS. LIGHT W WINDS
BECOME SW UNDER 10 KTS. CONFIDENCE: HIGH
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
UPDATE...HALBLAUB
SHORT TERM...ROSSI
LONG TERM...SALTZMAN
AVIATION...HALBLAUB
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
1122 PM CST WED DEC 2 2015
.SHORT TERM...(TONIGHT THROUGH SATURDAY)
ISSUED AT 320 PM CST WED DEC 2 2015
LITTLE IN THE WAY OF SENSIBLE WX IS EXPECTED DURING THIS PERIOD OF
THE FORECAST. AS THE UPPER LEVEL CLOSED LOW OVER THE GREAT LAKES
CONTS TO PULL OFF TO THE EAST...THE SURFACE RIDGE AXIS WILL
DEVELOP EAST TONIGHT. WITH LIGHT WINDS AND CLEAR WINDS WE ARE
EXPECTING SOME PRETTY CHILLY LOWS OVER THE SNOW COVER AREAS TO
THE NORTH. ON THE SOUTHERN EDGE OF THE SNOW COVER WHERE THERE HAS
BEEN A GOOD DEAL OF MELTING TODAY WE MAY SEE SOME PATCHY FOG
DEVELOP OVERNIGHT WITH THE RESIDUAL LOW-LEVEL MOISTURE REMAINS IN
PLACE. THE RAP INDICATES THIS...AND THE SREF HAS SOME FAIRLY HIGH
PROBS OF LOWER VISBY OVERNIGHT IN THIS AREA AS WELL. THIS PATTERN
MAY AGAIN REPEAT ON THURSDAY NIGHT INTO FRIDAY MORNING. OTHERWISE
A GOOD DEAL OF SUN AND MELTING ARE EXPECTED DURING THE DAY ON
THU/FRI WITH WARMER HIGHS.
A STRONGER LOW-LEVEL JET DEVELOPS ON FRI NIGHT AHEAD OF A FRONTAL
BOUNDARY THAT WILL MOV ACROSS THE CWA ON LATE SAT. WE MAY SEE
ENOUGH LOW LEVEL LIFT/MOISTURE RETURN TO SEE STRATUS
DEVELOP...STARTING OVER THE WESTERN CWA EARLY IN THE NIGHT
EXPANDING EWD TOWARD SAT MRNG. THE DEPTH OF THE MOIST LAYER ISN`T
OVERLY DEEP...BUT WE WOULDN`T BE SURPRISED TO SEE A LITTLE DZ DVLP
WITHIN THIS BAND IF MOISTURE PROFILES END UP SIMILAR TO THE NAM.
.LONG TERM...(SATURDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 320 PM CST WED DEC 2 2015
THE FRONTAL BOUNDARY WILL BE SLIPPING THROUGH THE CWA ON SAT
EVNG/NIGHT...BUT LITTLE IN THE WAY OF COLD AIR IS EXPECTED BEHIND
THE FRONT WITH TEMPERATURES REMAINING ABOVE NORMAL THROUGH THE
REST OF THE EXTENDED FORECAST. WE WILL CONT TO MENTION A SCHC CHC
OF RA/SN ON SAT NIGHT IN THE SOUTH...BUT LATEST TRENDS INDICATE
THIS MAY BE ABLE TO BE REMOVED IN COMING FORECASTS. THE REST OF
THE EXTENDED FORECAST WILL BE DRY.
&&
.AVIATION...(06Z TAFS FOR KOFK...KLNK AND KOMA.)
ISSUED AT 1121 PM CST WED DEC 2 2015
VFR CONDITIONS EXPECTED TO PREVAIL THRU THE FCST PD.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
SHORT TERM...BOUSTEAD
LONG TERM...BOUSTEAD
AVIATION...DEE
AREA FORECAST DISCUSSION
NWS ELKO NV
242 PM PST THU DEC 3 2015
.SYNOPSIS...A LOW PRESSURE SYSTEM HAS MOVED INTO CALIFORNIA
AND WILL WORK ITS WAY INTO THE SILVER STATE. MORE WINTRY WEATHER
IS ON ITS WAY...WITH A RAIN SNOW MIX ANTICIPATED TONIGHT FOR
PORTIONS OF HUMBOLDT COUNTY AND WILL IMPACT NORTHEAST NEVADA AFTER
MIDNIGHT. SATURDAY WILL BE DRY. OVER ALL...THE GULF OF ALASKA IS
BECOMING ACTIVE AGAIN AND MORE SNOW STORMS EXPECTED NEXT
WEEK...AND MORE MODIFIED PACIFIC MOISTURE WILL WORKS ITS WAY INTO
NEVADA.
&&
.SHORT TERM...TONIGHT THROUGH SUNDAY. THE HRRR IS MUCH DRIER THAN
THE GFS OVER THE LKN CWA. AT 22Z THE TEMP AT KWMC WAS 58F WHILE
THE TEMP AT KEKO WAS 36F. THE PRECIP THAT DOES FALL IN HUMBOLDT
COUNTY TONIGHT WILL BE A RAIN/SNOW MIX.THE SANTA ROSA RANGE WILL
GET SEVERAL INCHES OF NEW SNOW...ABOVE 6500 FEET. THE PRECIP WILL
BE MUCH SLOWER TO MOVE INTO ELKO COUNTY. THERE IS SOME AMOUNT OF
UNCERTAINITY REGARDING ACCUMULATIONS IN THE VALLEYS. AT THIS
TIME...EXPECTING ANYWHERE FROM A TRACE TO ONE INCH OF NEW SNOWFALL
IN VALLEY LOCATIONS. IN THE WAKE OF THE FROPA...SHORT-LIVED
WESTERLY WINDS...AND THEN THE SOUTHERN FLOW KICKS IN AGAIN ACROSS
THE LKN CWA ON SATURDAY AND INTO SUNDAY...WHICH WILL HELP TO WARM
THE GREAT BASIN...AND BRING TEMPERATURES CLOSER TO NORMAL. THE
MEAN MAX TEMP FOR ELKO ON DEC 5TH AND DEC 6TH IS 39F.
.LONG TERM...SUNDAY THROUGH NEXT THURSDAY. OVERALL THE PERIOD
LOOKS ACTIVE WITH AVERAGE TO ABOVE AVERAGE TEMPS AND WINDY
CONDITIONS...ESPECIALLY TOWARDS THE END OF THE PERIOD. THE STORM
TRACK BEGINS NORTH OF THE AREA BUT GRADUALLY SHIFTS SOUTH. BEST
CHANCE FOR SNOW ACCUMULATION THROUGHOUT THE PERIOD IS THE
MOUNTAINS OF NORTHERN HUMBOLDT AND ELKO COUNTIES WHERE WELL OVER A
FOOT OF SNOW IS POSSIBLE.
SPECIFICALLY...A FRONTAL SYSTEM WILL BE HITTING THE WEST COAST
SUNDAY MORNING...SETTING UP SW FLOW OVER THE CWA. ALTHOUGH THIS
SYTEMS CONTAINS VERY HIGH WATER CONTENT (ATMOSPHERE RIVER)...THE
SIERRAS WILL STRIP MOST OF THE IT AS THE SYSTEMS LIFTS NE SUNDAY
AFTERNOON. A FEW SHOWERS ARE POSSIBLE IN NORTHERN HUMBOLDT AND
ELKO COUNTIES SUNDAY AFTERNOON WHEN THE 500MB TROF ASSOCIATED WITH
THE SYSTEM PASSES THROUGH...BUT OVERALL LITTLE IMPACT TO MOST OF
THE CWA. ANOTHER SYSTEM IS RIGHT ON ITS HEELS AND IMPACTS THE AREA
LATE MONDAY INTO MONDAY NIGHT; HOWEVER...THIS FRONTAL BOUNDARY IS
MORE ALIGNED WEST TO EAST THAN THE PREVIOUS ONE WHICH WAS MORE
NORTH TO SOUTH. THEREFORE...EXPECT AN OVERRUNNING SITUATION FOR
NORTHERN HUMBOLDT AND ELKO COUNTIES BEFORE THE TAIL END OF THE
500MB TROF PROGRESSES FAIRLY QUICKLY TO THE EAST TUESDAY. SOME
INDICATIONS THAT THE 500MB TROF MAY DIG A LITTLE TO THE SOUTHEAST SO
PRECIP COULD SHIFT SOUTH OF I80 FOR A SHORT TIME MONDAY NIGHT.
ONCE AGAIN...WITH THE MAIN STORM TRACK JUST TO THE NORTH MOST OF
THE CWA WILL SIMPLY EXPERIENCE CLOUD COVER AND INCREASE IN WINDS
WITH THE WAVE. ALSO IMPORTANT TO NOTE...SNOW LEVELS WILL RUN
FAIRLY HIGH (7K TO 8K) WITH THESE TWO SYSTEMS SO IF VALLEYS
RECEIVE ANY PRECIP MOST WILL BE IN FORM OF RAIN.
TUESDAY THROUGH THURSDAY NIGHT...SHORT-WAVE RIDGE BUILDS OVERHEAD
AND PROVIDES QUIET AND FAIRLY WARM (COMPARED TO RECENT TEMPS)
CONDITIONS FOR TUESDAY AND MOST OF WEDNESDAY. HOWEVER...IT QUICKLY
BREAKS DOWN AS A VERY STRONG JET (POLAR AND SUBTROPICAL COMBINED)
DRIVES ANOTHER WET SYSTEM INTO THE WEST COAST EARLY WEDNESDAY.
ONCE AGAIN THE SIERRAS WILL STRIP MOST OF THE MOISTURE...LEAVING
MOST OF THE AREA WITH CLOUD COVER...WINDY CONDITIONS...AND MILD
TEMPS. NOT SO MUCH THE CASE FOR AREAS NORTH OF I80...WHERE PRECIP
IS EXPECTED PRIMARILY ALONG HIGHER ELEVATIONS WEDNESDAY EVENING
THROUGH THURSDAY MORNING. HIGHEST PRECIP AMOUNTS SHOULD REMAIN
NEAR THE NV/ID BORDER. SNOW LEVELS REMAIN HIGH INITIALLY...BUT
DROP TO MOST VALLEY FLOORS EARLY THURSDAY WHEN 500MB HEIGHTS
DECREASE TO 552-555DM. THE MAIN IMPACT WITH THIS SYSTEM IS THE
WINDS...WHERE MANY AREAS COULD SEE WIND HEADLINES AS A 110-120KT
POLAR JET CUTS ACROSS NORTHERN NEVADA. CURRENT GRIDS DEPICTS THIS
WITH MANY HIGHER ELEVATIONS SEEING GUST TO NEAR 50KTS. AS THIS
SYSTEM DEPARTS EARLY THURSDAY...ANOTHER SYSTEM HITS THE WEST
COAST. HOWEVER...UNLIKE THE PREVIOUS ONES...ALL MODELS INDICATE IT
DIGS SOUTHEAST AS THE JET MAX REMAINS ON THE BACKSIDE OF THE 500MB
TROF. THIS LEADS TO PRECIP SPREADING THROUGHOUT THE AREA BEGINNING
THURSDAY AFTERNOON. THERE ARE SLIGHT TIMING AND TRACK DIFFERENCES
AMONGST THE MODELS BUT THAT IS TO BE EXPECTED BEING A WEEK AWAY.
&&
.AVIATION...COLD FRONT WILL PASS THROUGH THE AREA WITH THE
GREATEST IMPACTS FELT AT WMC AND EKO. CIGS LOWER TO NEAR MVFR BY
LATE TONIGHT OR EARLY TOMORROW MORNING AT WMC AND EKO WITH SNOW OR
RAIN SHOWERS FOR A VERY BRIEF PERIOD. CIGS LOWER AT ELY LATER BUT
SHOULD REMAIN VFR. THE OTHER IMPACT AT ELY IS THE STRONG SOUTHERLY
WINDS AHEAD OF THE FRONT TONIGHT...WITH GUST AOB 30KTS. NO
SIGNIFICANT ISSUES EXPECTED AT TPH WITH JUST HIGH CLOUD COVER. LOW
LEVEL ICING AND TURBULENCE IS ALSO EXPECTED WITH THIS SYSTEM.
&&
.LKN WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
97/85/85
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
727 PM EST FRI DEC 4 2015
.SYNOPSIS...
A FEW LIGHT RAIN SHOWERS WILL BE POSSIBLE INTO EARLY THIS EVENING,
NORTH OF THE NEW YORK STATE THRUWAY. DRY AND MILD WEATHER IS
EXPECTED SATURDAY THROUGH AT LEAST TUESDAY.
&&
.NEAR TERM /UNTIL 7 AM SATURDAY MORNING/...
730 PM UPDATE...
MODEL OUTPUT, AND ESPECIALLY MOS, HAS A POOR HANDLE ON THE LOW
STRATUS HANGING ON THIS EVENING. GIVEN TIME OF YEAR AND LONG NIGHT,
WILL GO WITH SAT IR TRENDS AND KEEP THE CLOUDS THICK THROUGH
SATURDAY MORNING, ESPECIALLY NORTH OF THE NY/PA BORDER.
ALSO RAISED MINS UNDER THE THICK STRATUS.
3 PM UPDATE...
THE SHORT WAVE HAS PASSED EAST INTO NEW ENGLAND. A FEW LIGHT RAIN
SHOWERS CONTINUE IN ONEIDA COUNTY. THIS SHOULD DIE QUICKLY AFTER
SUNSET. WARMER AIR COMING IN ALOFT AS THE UPPER LEVEL TROF MOVES
EAST. THE LOW LEVEL FLOW REMAINS NW BUT NOT ENOUGH TEMP
DIFFERENCE TO PICK UP LAKE MOISTURE. THE BIGGER PROBLEM WILL BE A
LARGE LOW LEVEL INVERSION TRAPPING THE MOISTURE AND CLOUDS BELOW
5K FT. CLOUDS WILL REMAIN IN PLACE TONIGHT. EDGE OF CLOUDS AT THE
FAR SRN EDGE OF CWA. MOST LOWS IN THE LOWER 30S BUT COULD BE
WARMER WITH ALL THE CLOUDS. THIS MORNING LOWS WERE ABOVE GUIDANCE
WITH ALL THE CLOUDS.
&&
.SHORT TERM /7 AM SATURDAY MORNING THROUGH MONDAY/...
3 PM UPDATE...
A LARGE SURFACE HIGH PRESSURE SYSTEM MOVES IN SATURDAY AND REMAINS
INTO SUNDAY. BIGGEST QUESTION IS WHEN THIS HIGH WILL MIX DOWN
ENOUGH DRY AIR TO BREAK THE LOW LEVEL INVERSION TRAPPING MOISTURE.
THIS LAYER WILL THIN AND ERODE FROM THE SW. MOISTURE OFF OF LAKE
ONTARIO WILL DIMINISH WITH WARM AIR MOVING IN ALOFT AND WINDS
WEAKENING. CLOUDY SKIES ACROSS MOST OF THE CWA SATURDAY MORNING
WILL BECOME MAINLY CLEAR BY SUNSET AND THEN CONTINUE THROUGH
SUNDAY. THE SUNNY SKIES SUNDAY WITH 850MB AT +6C WILL PUT SFC
TEMPS IN THE 50S.
SUNDAY NIGHT A SYSTEM APPROACHES FROM THE SW AND MOVES ACROSS PA
SUN NGT AND MON. NOT ENOUGH MOISTURE SO REMAINS DRY BUT CLOUDS
WILL INCREASE.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
3 PM FRI UPDATE...
ANOTHER WARM PERIOD WITH LITTLE PRECIPITATION. HIGHS IN THE 40S
AND LOWS IN THE 30S. FOLLOWED WPC LEAD AND LEFT POPS AT SLIGHT
CHANCE WED NGT TO FRIDAY. A MORE ACTIVE PATTERN WITH A ZONAL
PATTERN BECOMING AMPLIFIED END OF WEEK. A WEAK CLOSED UPPER LEVEL
LOW MOVES THROUGH MONDAY AND EAST TUESDAY. HIGH PRESSURE AND DRY
AIR SHOULD KEEP ANY RAIN TO THE COASTAL PLAIN AND OUT OF OUR CWA.
WED TO SAT MODEL DISAGREEMENT BUT A SERIES OF SHORT WAVES AS AN
UPPER LEVEL TROF APPROACHES. EURO DEEPER AND WETTER THAN GFS.
WEATHER NOT A PROBLEM WITH TEMPERATURES AT THE SFC AND 850MB ABOVE
FREEZING.
&&
.AVIATION /01Z SATURDAY THROUGH WEDNESDAY/...
GOES 11-3.9 MICRON SATELLITE IMAGERY SHOWS AN OVERCAST LAYER
ACROSS MOST OF NEW YORK STATE. THE SOUTHERN BOUNDARY OF THIS
CLOUD LAYER WAS ACROSS THE NORTHERN TIER OF PENNSYLVANIA. CEILINGS
WERE RUNNING BETWEEN 2000 AND 3000 FEET ABOVE GROUND LEVEL WITH A
FEW SPOTS, NOTABLY ITH AND PEO, BELOW 2000 FEET. THERE WAS NO IFR
CONDITIONS IN CENTRAL NY. SOUTHWESTERN NY HAD A LITTLE IFR AT OLE
AND JHW WHICH ARE HIGH ELEVATION TERMINALS. THE SURFACE WINDS WERE
WEST TO NORTHWEST 5 TO 10 KNOTS WITH THE BGM RADAR WIND PROFILE
SHOWING A WEST TO NORTHWEST FLOW UP TO ABOUT 4000 FEET ABOVE
GROUND LEVEL. THIS CLOUD LAYER WAS ROUGHLY AROUND 925 MB AND THE
CMC AND RAP MODELS HAVE THE BEST HANDLE ON THE POSITIONING OF THE
CLEAR-CLOUD BOUNDARY AT THIS TIME IN THE RH FIELDS.
ALL MODELS SHOW THE WINDS AT 925 MB VEERING TO MORE NORTHERLY
OVERNIGHT AS HIGH PRESSURE BUILDS EAST WITH LOW-LEVEL SUBSIDENCE.
HENCE BELIEVE CLOUDS WILL REMAIN PRETTY MUCH WHERE THEY ARE
THROUGH THE NIGHT AND THEN ERODE TO THE NORTH AND EAST SATURDAY
MORNING AS SEEN ON THE RAP AND CMC MODELS. ONLY AVP LOOKS TO
ESCAPE THE CLOUD COVER AND BE VFR THROUGH THE FORECAST PERIOD.
REST OF TAFS WILL REMAIN OVERCAST GENERALLY MVFR UNTIL LATE
MORNING/EARLY AFTERNOON SATURDAY.
WINDS WILL BE MAINLY WEST TO NORTHWEST UNDER 10 KNOTS THROUGH
SATURDAY.
.OUTLOOK...
SAT NIGHT THROUGH WED...QUIET PERIOD. MAINLY VFR.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...TAC
NEAR TERM...DJP/TAC
SHORT TERM...TAC
LONG TERM...TAC
AVIATION...DJN
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
639 PM EST FRI DEC 4 2015
.SYNOPSIS...
A FEW LIGHT RAIN SHOWERS WILL BE POSSIBLE INTO EARLY THIS EVENING,
NORTH OF THE NEW YORK STATE THRUWAY. DRY AND MILD WEATHER IS
EXPECTED SATURDAY THROUGH AT LEAST TUESDAY.
&&
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
3 PM UPDATE...
THE SHORT WAVE HAS PASSED EAST INTO NEW ENGLAND. A FEW LIGHT RAIN
SHOWERS CONTINUE IN ONEIDA COUNTY. THIS SHOULD DIE QUICKLY AFTER
SUNSET. WARMER AIR COMING IN ALOFT AS THE UPPER LEVEL TROF MOVES
EAST. THE LOW LEVEL FLOW REMAINS NW BUT NOT ENOUGH TEMP
DIFFERENCE TO PICK UP LAKE MOISTURE. THE BIGGER PROBLEM WILL BE A
LARGE LOW LEVEL INVERSION TRAPPING THE MOISTURE AND CLOUDS BELOW
5K FT. CLOUDS WILL REMAIN IN PLACE TONIGHT. EDGE OF CLOUDS AT THE
FAR SRN EDGE OF CWA. MOST LOWS IN THE LOWER 30S BUT COULD BE
WARMER WITH ALL THE CLOUDS. THIS MORNING LOWS WERE ABOVE GUIDANCE
WITH ALL THE CLOUDS.
&&
.SHORT TERM /6 AM SATURDAY MORNING THROUGH MONDAY/...
3 PM UPDATE...
A LARGE SURFACE HIGH PRESSURE SYSTEM MOVES IN SATURDAY AND REMAINS
INTO SUNDAY. BIGGEST QUESTION IS WHEN THIS HIGH WILL MIX DOWN
ENOUGH DRY AIR TO BREAK THE LOW LEVEL INVERSION TRAPPING MOISTURE.
THIS LAYER WILL THIN AND ERODE FROM THE SW. MOISTURE OFF OF LAKE
ONTARIO WILL DIMINISH WITH WARM AIR MOVING IN ALOFT AND WINDS
WEAKENING. CLOUDY SKIES ACROSS MOST OF THE CWA SATURDAY MORNING
WILL BECOME MAINLY CLEAR BY SUNSET AND THEN CONTINUE THROUGH
SUNDAY. THE SUNNY SKIES SUNDAY WITH 850MB AT +6C WILL PUT SFC
TEMPS IN THE 50S.
SUNDAY NIGHT A SYSTEM APPROACHES FROM THE SW AND MOVES ACROSS PA
SUN NGT AND MON. NOT ENOUGH MOISTURE SO REMAINS DRY BUT CLOUDS
WILL INCREASE.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
3 PM FRI UPDATE...
ANOTHER WARM PERIOD WITH LITTLE PRECIPITATION. HIGHS IN THE 40S
AND LOWS IN THE 30S. FOLLOWED WPC LEAD AND LEFT POPS AT SLIGHT
CHANCE WED NGT TO FRIDAY. A MORE ACTIVE PATTERN WITH A ZONAL
PATTERN BECOMING AMPLIFIED END OF WEEK. A WEAK CLOSED UPPER LEVEL
LOW MOVES THROUGH MONDAY AND EAST TUESDAY. HIGH PRESSURE AND DRY
AIR SHOULD KEEP ANY RAIN TO THE COASTAL PLAIN AND OUT OF OUR CWA.
WED TO SAT MODEL DISAGREEMENT BUT A SERIES OF SHORT WAVES AS AN
UPPER LEVEL TROF APPROACHES. EURO DEEPER AND WETTER THAN GFS.
WEATHER NOT A PROBLEM WITH TEMPERATURES AT THE SFC AND 850MB ABOVE
FREEZING.
&&
.AVIATION /00Z SATURDAY THROUGH WEDNESDAY/...
GOES 11-3.9 MICRON SATELLITE IMAGERY SHOWS AN OVERCAST LAYER
ACROSS MOST OF NEW YORK STATE. THE SOUTHERN BOUNDARY OF THIS
CLOUD LAYER WAS ACROSS THE NORTHERN TIER OF PENNSYLVANIA. CEILINGS
WERE RUNNING BETWEEN 2000 AND 3000 FEET ABOVE GROUND LEVEL WITH A
FEW SPOTS, NOTABLY ITH AND PEO, BELOW 2000 FEET. THERE WAS NO IFR
CONDITIONS IN CENTRAL NY. SOUTHWESTERN NY HAD A LITTLE IFR AT OLE
AND JHW WHICH ARE HIGH ELEVATION TERMINALS. THE SURFACE WINDS WERE
WEST TO NORTHWEST 5 TO 10 KNOTS WITH THE BGM RADAR WIND PROFILE
SHOWING A WEST TO NORTHWEST FLOW UP TO ABOUT 4000 FEET ABOVE
GROUND LEVEL. THIS CLOUD LAYER WAS ROUGHLY AROUND 925 MB AND THE
CMC AND RAP MODELS HAVE THE BEST HANDLE ON THE POSITIONING OF THE
CLEAR-CLOUD BOUNDARY AT THIS TIME IN THE RH FIELDS.
ALL MODELS SHOW THE WINDS AT 925 MB VEERING TO MORE NORTHERLY
OVERNIGHT AS HIGH PRESSURE BUILDS EAST WITH LOW-LEVEL SUBSIDENCE.
HENCE BELIEVE CLOUDS WILL REMAIN PRETTY MUCH WHERE THEY ARE
THROUGH THE NIGHT AND THEN ERODE TO THE NORTH AND EAST SATURDAY
MORNING AS SEEN ON THE RAP AND CMC MODELS. ONLY AVP LOOKS TO
ESCAPE THE CLOUD COVER AND BE VFR THROUGH THE FORECAST PERIOD.
REST OF TAFS WILL REMAIN OVERCAST GENERALLY MVFR UNTIL LATE
MORNING/EARLY AFTERNOON SATURDAY.
WINDS WILL BE MAINLY WEST TO NORTHWEST UNDER 10 KNOTS THROUGH
SATURDAY.
.OUTLOOK...
SAT NIGHT THROUGH WED...QUIET PERIOD. MAINLY VFR.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...TAC
NEAR TERM...TAC
SHORT TERM...TAC
LONG TERM...TAC
AVIATION...DJN
AREA FORECAST DISCUSSION
NWS BISMARCK ND
939 PM CST FRI DEC 4 2015
.UPDATE...
ISSUED AT 929 PM CST FRI DEC 4 2015
NO SIGNIFICANT UPDATES TO THE GOING FORECAST THIS EVENING. STRONG
SOUTHERLY WINDS AHEAD OF A COLD FRONT IN EASTERN NORTH DAKOTA
WITH LIGHT TO MODERATE SOUTHWEST TO WEST WINDS OVER WESTERN NORTH
DAKOTA WILL KEEP TEMPERATURES RATHER UNIFORM ACROSS THE FORECAST
AREA TONIGHT...EVEN OVER THE REMAINING SNOWPACK OVER THE FAR SOUTH
CENTRAL INTO THE JAMES RIVER VALLEY. INCREASING CLOUDS TRACKING
NORTHEAST FROM SOUTH DAKOTA WILL ALSO HELP KEEP TEMPERATURES FROM
FALLING LIKE THE PAST FEW NIGHTS OVER THE SNOWPACK. UPDATED LATEST
SENSIBLE WEATHER ELEMENTS AND INTERPOLATED TO A CONSENSUS OF SHORT
TERM HOURLY TEMPERATURES FOR THE OVERNIGHT PERIOD. RESULTING IN
VERY FEW CHANGES FROM THE PREVIOUS FORECAST.
UPDATE ISSUED AT 627 PM CST FRI DEC 4 2015
A WEAK COLD FRONT WILL TRAVERSE THE FORECAST AREA TONIGHT. STRONG
SOUTHERLY FLOW OVER THE JAMES RIVER VALLEY EARLY THIS EVENING WILL
DIMINISH BY LATE EVENING AS FLOW SHIFTS MORE SOUTHWEST...AND
EVENTUALLY WEST SATURDAY MORNING.
THE SOUTHWEST TO WEST FLOW SHOULD KEEP TEMPERATURES RATHER UNIFORM
TONIGHT COMPARED TO PREVIOUS NIGHTS...EVEN OVER THE DECAYING
SNOWPACK. THE TURBULENCE IN THE LOW LEVELS SHOULD ALSO HELP TO
INHIBIT ANY FOG FORMATION WHERE SNOWMELT OCCURRED DURING THE DAY.
FOR THE EVENING UPDATE...ONLY SOME MINOR ADJUSTMENTS TO SKY COVER
AND POPULATED THE LATEST SENSIBLE WEATHER ELEMENTS.
&&
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 320 PM CST FRI DEC 4 2015
MILD AND QUIET WEATHER WILL CONTINUE THROUGH SATURDAY.
AS OF 21 UTC...IT IS APPARENT THAT THE LOW-LEVEL INVERSION IS ONLY
SLOWLY BEING ERODED IN SOUTHERLY FLOW...AS SURFACE GUSTS ARE BEING
HELD UNDER 30 KT EVEN IN THE JAMES RIVER VALLEY. FORECAST SOUNDING
PROFILES FROM THE RAP AND HRRR CONTINUE TO SUPPORT WINDS AROUND
60 KT WITHIN 2000 FT AGL THROUGH EARLY EVENING IN EAST CENTRAL ND
AND SO WE WILL HAVE TO MONITOR FOR STRONGER GUSTS...BUT THE CHANCE
OF ADVISORY-TYPE GUSTS APPEARS TO BE DWINDLING.
A MODEST COLD FRONT WILL CROSS THE AREA TONIGHT...TURNING WINDS TO
THE WEST...AND COOLING THE AIR MASS A BIT BY SATURDAY WHEN 850-MB
TEMPERATURES ARE EXPECTED TO DROP TO +1 TO +3 C. HOWEVER...GIVEN
THE FAVORABLE LOW-LEVEL WESTERLY FLOW AND CONTINUED EROSION OF THE
SNOW PACK...WE STILL EXPECT HIGHS IN THE 40S F IN MANY PLACES ON
SATURDAY. IT ALSO APPEARS THAT THE NEAR-SURFACE LAYER WILL BE TOO
TURBULENT TO SUPPORT FOG FORMATION TONIGHT IN AREAS THAT HAVE HAD
SNOWMELT DURING THE DAY.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 320 PM CST FRI DEC 4 2015
THE MAIN HIGHLIGHTS IN THE LONG TERM PERIOD ARE ABOVE NORMAL HIGH
TEMPERATURES THROUGH THE PERIOD...WITH HIGHS IN THE 40S AND SOME 50S
ESPECIALLY SUNDAY AND WEDNESDAY. A COOLING TREND INITIATES FRIDAY
AND CONTINUES THROUGH THE UPCOMING WEEKEND. ALTHOUGH COOLER
CONDITIONS EXPECTED FRIDAY...HIGH TEMPERATURES STILL REMAIN ABOVE
NORMAL WITH HIGHS 35F TO 40F. THE OVERALL PATTERN OF A NEAR ZONAL
FLOW CONTINUES WITH QUICK MOVING SHORTWAVES AND ASSOCIATED SURFACE
FEATURES SLIDING ACROSS WESTERN AND CENTRAL NORTH DAKOTA. THE MAIN
DIFFERENCE ON THE 12Z GFS/ECMWF MODELS RUNS TODAY IS A MORE
WIDESPREAD CHANCE OF MOSTLY RAIN SHOWERS ON TUESDAY ACROSS WESTERN
AND CENTRAL NORTH DAKOTA. ALTHOUGH SOME SNOW SHOWERS ARE POSSIBLE
DURING THE EARLY MORNING. ANOTHER FAIRLY WEAK SHORTWAVE IS SLATED
FOR THURSDAY INTO THURSDAY NIGHT....WITH A POTENTIALLY STRONGER
SHORTWAVE FRIDAY INTO THE WEEKEND. HOWEVER IT IS EVIDENT JUST FROM
THE GFS ENSEMBLE HEIGHTS THAT NEXT WEEKENDS SHORTWAVE HAS A LOT OF
UNCERTAINTY...WITH SEVERAL POSSIBLE SOLUTIONS. THE SUPERBLEND
CURRENTLY HAS A SLIGHT CHANCE/CHANCE OF RAIN AND SNOW FRIDAY/FRIDAY
NIGHT.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 929 PM CST FRI DEC 4 2015
A WEAK COLD FRONT WILL TRACK ACROSS THE FORECAST AREA TONIGHT WITH
A SOUTHWEST TO WEST WIND TONIGHT...SHIFTING MORE WEST TO NORTHWEST
LATE TONIGHT AND SATURDAY. VFR CONDITIONS ARE ANTICIPATED AT ALL
TAF SITES TONIGHT. FORECAST MODELS ARE INDICATING SOME MVFR
CEILINGS DROPPING DOWN INTO WESTERN NORTH DAKOTA SATURDAY MORNING.
HOWEVER...COMPARING FORECAST 6HR LOW LEVEL RH FROM THE 18Z NAM TO
THE CURRENT OBSERVATIONS UPSTREAM...THE AMOUNT OF LOW LEVEL
MOISTURE SEEMS OVERDONE. FOR NOW MENTIONED A SCATTERED LAYER OF
MVFR CIGS AT KISN AND KDIK. WILL CONTINUE TO MONITOR. WINDS
TONIGHT SHOULD INHIBIT FOG FORMATION OVER THE SNOWPACK...INCLUDING
KJMS.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...TWH
SHORT TERM...CJS
LONG TERM...KS
AVIATION...TWH
AREA FORECAST DISCUSSION
NWS BISMARCK ND
640 PM CST FRI DEC 4 2015
.UPDATE...
ISSUED AT 627 PM CST FRI DEC 4 2015
A WEAK COLD FRONT WILL TRAVERSE THE FORECAST AREA TONIGHT. STRONG
SOUTHERLY FLOW OVER THE JAMES RIVER VALLEY EARLY THIS EVENING WILL
DIMINISH BY LATE EVENING AS FLOW SHIFTS MORE SOUTHWEST...AND
EVENTUALLY WEST SATURDAY MORNING.
THE SOUTHWEST TO WEST FLOW SHOULD KEEP TEMPERATURES RATHER UNIFORM
TONIGHT COMPARED TO PREVIOUS NIGHTS...EVEN OVER THE DECAYING
SNOWPACK. THE TURBULENCE IN THE LOW LEVELS SHOULD ALSO HELP TO
INHIBIT ANY FOG FORMATION WHERE SNOWMELT OCCURRED DURING THE DAY.
FOR THE EVENING UPDATE...ONLY SOME MINOR ADJUSTMENTS TO SKY COVER
AND POPULATED THE LATEST SENSIBLE WEATHER ELEMENTS.
&&
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 320 PM CST FRI DEC 4 2015
MILD AND QUIET WEATHER WILL CONTINUE THROUGH SATURDAY.
AS OF 21 UTC...IT IS APPARENT THAT THE LOW-LEVEL INVERSION IS ONLY
SLOWLY BEING ERODED IN SOUTHERLY FLOW...AS SURFACE GUSTS ARE BEING
HELD UNDER 30 KT EVEN IN THE JAMES RIVER VALLEY. FORECAST SOUNDING
PROFILES FROM THE RAP AND HRRR CONTINUE TO SUPPORT WINDS AROUND
60 KT WITHIN 2000 FT AGL THROUGH EARLY EVENING IN EAST CENTRAL ND
AND SO WE WILL HAVE TO MONITOR FOR STRONGER GUSTS...BUT THE CHANCE
OF ADVISORY-TYPE GUSTS APPEARS TO BE DWINDLING.
A MODEST COLD FRONT WILL CROSS THE AREA TONIGHT...TURNING WINDS TO
THE WEST...AND COOLING THE AIR MASS A BIT BY SATURDAY WHEN 850-MB
TEMPERATURES ARE EXPECTED TO DROP TO +1 TO +3 C. HOWEVER...GIVEN
THE FAVORABLE LOW-LEVEL WESTERLY FLOW AND CONTINUED EROSION OF THE
SNOW PACK...WE STILL EXPECT HIGHS IN THE 40S F IN MANY PLACES ON
SATURDAY. IT ALSO APPEARS THAT THE NEAR-SURFACE LAYER WILL BE TOO
TURBULENT TO SUPPORT FOG FORMATION TONIGHT IN AREAS THAT HAVE HAD
SNOWMELT DURING THE DAY.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 320 PM CST FRI DEC 4 2015
THE MAIN HIGHLIGHTS IN THE LONG TERM PERIOD ARE ABOVE NORMAL HIGH
TEMPERATURES THROUGH THE PERIOD...WITH HIGHS IN THE 40S AND SOME 50S
ESPECIALLY SUNDAY AND WEDNESDAY. A COOLING TREND INITIATES FRIDAY
AND CONTINUES THROUGH THE UPCOMING WEEKEND. ALTHOUGH COOLER
CONDITIONS EXPECTED FRIDAY...HIGH TEMPERATURES STILL REMAIN ABOVE
NORMAL WITH HIGHS 35F TO 40F. THE OVERALL PATTERN OF A NEAR ZONAL
FLOW CONTINUES WITH QUICK MOVING SHORTWAVES AND ASSOCIATED SURFACE
FEATURES SLIDING ACROSS WESTERN AND CENTRAL NORTH DAKOTA. THE MAIN
DIFFERENCE ON THE 12Z GFS/ECMWF MODELS RUNS TODAY IS A MORE
WIDESPREAD CHANCE OF MOSTLY RAIN SHOWERS ON TUESDAY ACROSS WESTERN
AND CENTRAL NORTH DAKOTA. ALTHOUGH SOME SNOW SHOWERS ARE POSSIBLE
DURING THE EARLY MORNING. ANOTHER FAIRLY WEAK SHORTWAVE IS SLATED
FOR THURSDAY INTO THURSDAY NIGHT....WITH A POTENTIALLY STRONGER
SHORTWAVE FRIDAY INTO THE WEEKEND. HOWEVER IT IS EVIDENT JUST FROM
THE GFS ENSEMBLE HEIGHTS THAT NEXT WEEKENDS SHORTWAVE HAS A LOT OF
UNCERTAINTY...WITH SEVERAL POSSIBLE SOLUTIONS. THE SUPERBLEND
CURRENTLY HAS A SLIGHT CHANCE/CHANCE OF RAIN AND SNOW FRIDAY/FRIDAY
NIGHT.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 627 PM CST FRI DEC 4 2015
A WEAK COLD FRONT WILL TRACK ACROSS THE FORECAST AREA TONIGHT WITH
A SOUTHWEST TO WEST WIND TONIGHT...SHIFTING MORE WEST TO NORTHWEST
LATE TONIGHT AND SATURDAY. VFR CONDITIONS ARE ANTICIPATED AT ALL
TAF SITES TONIGHT. FORECAST MODELS ARE INDICATING SOME MVFR
CEILINGS DROPPING DOWN INTO WESTERN NORTH DAKOTA SATURDAY MORNING.
HOWEVER...COMPARING FORECAST 6HR LOW LEVEL RH FROM THE 18Z NAM TO
THE CURRENT OBSERVATIONS UPSTREAM...THE AMOUNT OF LOW LEVEL
MOISTURE SEEMS OVERDONE. FOR NOW MENTIONED A SCATTERED LAYER OF
MVFR CIGS AT KISN AND KDIK. WILL CONTINUE TO MONITOR. WINDS
TONIGHT SHOULD INHIBIT FOG FORMATION OVER THE SNOWPACK...INCLUDING
KJMS.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...TWH
SHORT TERM...CJS
LONG TERM...KS
AVIATION...TWH
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1245 AM CST THU DEC 3 2015
.UPDATE...
ISSUED AT 1245 AM CST THU DEC 3 2015
EMBEDDED S/WV TRACKING EAST-SOUTHEAST ACROSS THE REGION EARLY
THIS MORNING...GENERATING AN INCREASE IN MID TO UPPER LEVEL
CLOUDS. REGIONAL RADAR SHOWING SOME WEAK RETURNS...THOUGH WITH
CIGS AT OR ABOVE 10-15K FT AGL NOTHING IS REACHING THE GROUND.
TEMPERATURES DROPPING WHERE OUR SNOW PACK IS THE GREATEST ACROSS
THE FAR SOUTH CENTRAL AND SOUTHEAST. EXPECT THIS TREND FOR HIGHS
TOMORROW AS WELL.
UPDATE ISSUED AT 930 PM CST WED DEC 2 2015
AN UPPER LEVEL SHORTWAVE AND ASSOCIATED SURFACE LOW WILL TRACK
ACROSS NORTHERN SASKATCHEWAN INTO MANITOBA TONIGHT. A SURFACE
TROUGH EXTENDING SOUTH FROM THE LOW WILL TRACK ACROSS WESTERN AND
CENTRAL NORTH DAKOTA. A DECENT FALL-RISE COUPLET IS NOTED WITH THE
SURFACE TROUGH...MAINLY ACROSS THE PRAIRIE PROVINCES OF CANADA BUT
THIS SHOULD HELP KEEP A STEADY SOUTHWEST SWITCHING WEST WIND
ACROSS THE NORTHWEST AND NORTH CENTRAL TONIGHT. THIS...IN ADDITION
TO INCREASING MID AND HIGH LEVEL CLOUD SHIELD SHOULD KEEP
TEMPERATURES FROM FALLING BELOW THE 20S ACROSS MOST OF THE WEST
AND NORTH CENTRAL. LOW TEMPERATURES WERE ADJUSTED A BIT HIGHER
THAN PREVIOUS FORECAST ACROSS THE NORTH.
SNOWPACK OVER THE FAR SOUTH CENTRAL AND JAMES RIVER VALLEY HAS
ALLOWED TEMPERATURES TO FALL INTO THE TEENS...WITH A FEW SINGLE
DIGIT READINGS ALREADY LATE THIS EVENING. HERE WE THINK THERE
COULD BE A DROP OF A FEW MORE DEGREES BEFORE BEFORE HIGH CLOUDS
BEGIN TO INCREASE AND PERHAPS WE SEE A LITTLE MORE MIXING WITH A
SLIGHT INCREASE IN SOUTHWEST FLOW AHEAD OF THE SURFACE TROUGH.
THUS LOWERED TEMPERATURES HERE A BIT MORE LATE THIS EVENING BEFORE
KEEPING THEM NEARLY STEADY OVERNIGHT.
OTHER THAN TEMPERATURES AND A FEW TWEAKS TO SKY COVER WITH THE
HIGH CLOUDS TRAVERSING THE FORECAST AREA TONIGHT INTO THURSDAY
MORNING...NO CHANGES TO THE GOING FORECAST. A FEW REFLECTIVITIES
NOTED OVER NORTHEAST MONTANA DROPPING SOUTHEAST BUT THINK THEY
WILL CONTINUE TO WEAKEN AS THEY MOVE INTO NORTH DAKOTA AS
ATMOSPHERE REMAINS QUITE DRY. WITH THE STEADY WINDS NORTH AND
INCREASING CLOUDS WILL HOLD OFF ON ANY MENTION OF FOG FOR NOW. IF
ANYTHING WOULD DEVELOP OVER/ADJACENT TO THE SNOWPACK...WOULD
EXPECT IT TO BE VERY PATCHY IN NATURE.
UPDATE ISSUED AT 625 PM CST WED DEC 2 2015
CLEAR SKIES ACROSS WESTERN AND CENTRAL NORTH DAKOTA EARLY THIS
EVENING. HOWEVER...HIGH LEVEL CLOUDS ARE BEGINNING TO ENCROACH
INTO THE NORTHWEST. MAIN FORECAST ISSUE WAS IN THE SOUTHEAST CWA
WHERE EARLY EVENING TEMPERATURES ARE ALREADY NEARING FORECAST
LOWS. NEEDED TO LOWER TEMPERATURES INTO THE HIGH SINGLE DIGITS TO
LOWER TEENS FROM AROUND CARRINGTON AND JAMESTOWN SOUTH AND WEST TO
LINTON...ASHLEY AND OAKES. WILL NEED TO MONITOR THESE AS WE
CONTINUE THROUGH THE EVENING. ELSEWHERE TEMPERATURES LOOK
REASONABLE FOR NOW. LOW TEMPERATURES FARTHER WEST WILL DEPEND ON
HOW MUCH THE THICKER CIRRUS ERODES AS IT MOVES INTO THE DRIER
ATMOSPHERE OVER ND...AND IF THE WINDS DROP OFF OR HOLD STEADY WITH
THE PASSAGE OF A WEAK SURFACE TROUGH.
LITTLE CONCERNED ABOUT POSSIBLE PATCHY FOG ALONG THE PERIPHERY OF
THE SNOW FIELD AS DEWPOINT TEMPERATURES ARE HOLDING UP INTO THE
LOW TO MID 20S. WILL TAKE ANOTHER LOOK WITH THE LATE EVENING
UPDATE.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 222 PM CST WED DEC 2 2015
LATEST SUITE OF SATELLITE IMAGERY SHOWS A CLEAR SKY ACROSS WESTERN
AND CENTRAL NORTH DAKOTA THIS AFTERNOON WITH INCREASING MID/HIGH
CLOUDS (700MB-500MB) NOW INTO CENTRAL MONTANA. WATER VAPOR SHOWS A
SHORTWAVE TROUGH PUSHING THROUGH THE IDAHO PANHANDLE WITH A SURFACE
TROUGH STRETCHING FROM ALBERTA SOUTH INTO WESTERN MONTANA. FOR
TONIGHT...EXPECT A CLEAR SKY IN THE EVENING GIVING WAY TO A PARTLY/MOSTLY
CLOUDY SKY WEST INTO PORTIONS OF WEST CENTRAL NORTH DAKOTA. ALL
MODELS REMAIN DRY WITH THIS SHORTWAVE AND SURFACE TROUGH AS IT
SHIFTS THROUGH 06Z-15Z THURSDAY. WILL MAINTAIN A DRY FORECAST WITH
INCREASING CLOUDS WEST AND PORTIONS OF WEST CENTRAL. THE JAMES
RIVER VALLEY WILL REMAIN CLEAR UNTIL 12Z THURSDAY AND WITH FAIRLY
FRESH SNOW COVER ON THE GROUND...THIS IS THE AREA WHERE RADIATIONAL
COOLING WILL BE MAXIMIZED. OVERNIGHT LOWS IN THE LOWER TEENS JAMES
RIVER VALLEY WITH MID TEENS TO LOWER 20S ELSEWHERE...ESPECIALLY
WEST IN AREAS LACKING SNOW COVER AND ADDITIONAL CLOUDS ARRIVING
OVERNIGHT. LOOKED AT THE POTENTIAL FOR FOG IN THE JAMES RIVER
VALLEY LATE TONIGHT INTO EARLY THURSDAY MORNING. THE HRRR SHOWS
NOTHING DEVELOPING AT THIS TIME. WITH HIGHS IN THE UPPER 20S TO
NEAR 32F WEDNESDAY...FEEL THE BOUNDARY LAYER WILL NOT BE MOIST
ENOUGH TO SUPPORT AREAS OF FOG. OTHERWISE...CLOUDS DECREASING
QUICKLY AFTER SUNRISE /12Z- 15Z/ FOLLOWED BY SUNNY CONDITIONS AND
HIGHS 35 TO 45.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 222 PM CST WED DEC 2 2015
DRY CONDITIONS AND MILD TEMPERATURES HIGHLIGHT THE EXTENDED PERIOD.
AN UPPER LEVEL RIDGE WILL BE LOCATED OVER WESTERN AND CENTRAL NORTH
DAKOTA BY THURSDAY EVENING AND INTO THE OVERNIGHT HOURS...BRINGING
CALM AND DRY CONDITIONS. EXPECT MUCH WARMER TEMPERATURES BY FRIDAY
AFTERNOON...WITH WIDESPREAD HIGHS IN THE LOW TO MID 40S.
BY FRIDAY EVENING AND INTO SATURDAY MORNING...WE WILL TRANSITION
INTO A BRIEF PERIOD OF SOUTHWESTERLY FLOW WITH THE APPROACH OF AN
UPPER LEVEL SHORTWAVE TROUGH AND ASSOCIATED COLD FRONT AT THE
SURFACE. AT THE MOMENT...IT APPEARS THAT ANY PRECIPITATION
ASSOCIATED WITH SAID COLD FRONT WILL BE LIMITED TO NORTH OF THE
CANADIAN BORDER...WHERE THE STRONGER FORCING WILL RESIDE.
A RATHER PROGRESSIVE AND MILD PATTERN WILL CONTINUE THROUGH THE REST
OF THE PERIOD...WITH SUBTLE WAVES MOVING QUICKLY THROUGH THE REGION.
LITTLE IF ANY PRECIPITATION WILL BE POSSIBLE WITH ANY OF THESE
WAVES...AND TEMPERATURES WILL GENERALLY REMAIN ABOVE AVERAGE.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1245 AM CST THU DEC 3 2015
VFR CONDITIONS EXPECTED THROUGH THE TAF PERIOD WITH A WESTERLY
SURFACE FLOW. WILL MONITOR FOR PATCHY FOG BUT FOR NOW CONFIDENCE
TOO LOW TO ADD TO TAFS.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...NH
SHORT TERM...KS
LONG TERM...ZH
AVIATION...NH
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
601 PM EST THU DEC 3 2015
.SYNOPSIS...
CLOUDS WILL LINGER ACROSS PORTIONS OF THE AREA TONIGHT AS AN
UPPER LEVEL LOW CONTINUES TO MOVE AWAY FROM THE REGION. HIGH
PRESSURE WILL BECOME ESTABLISHED IN THE OHIO VALLEY BY FRIDAY...
WHICH WILL PROVIDE ABUNDANT SUNSHINE AND ALLOW FOR TEMPERATURES TO
MODERATE THROUGH THE UPCOMING WEEKEND. A WEAK AREA OF LOW PRESSURE
WILL APPROACH THE AREA BY EARLY MONDAY...OFFERING THE NEXT CHANCE
OF RAIN.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
NORTHWEST FLOW ALOFT WILL DOMINATE AS UPPER LEVEL LOW CONTINUES TO
TRANSLATE EAST INTO NEW ENGLAND. SURFACE HIGH PRESSURE OVER THE
PLAINS TO BUILD EAST BECOMING CENTERED OVER THE OHIO VALLEY BY 12Z
FRIDAY. A GOOD DEAL OF LOW LEVEL MOISTURE LINGERS ACROSS THE AREA.
LATEST VISIBLE SATL SHOWS MOST OF ILN/S COVERED BY LOW CLOUDS.
MORE BREAKS AND DRYING SHOWING UP ACRS PORTIONS OF SOUTHERN AND
EASTERN INDIANA. ADDITIONAL MOISTURE OVER ILLINOIS MOVING INTO
INDIANA. HRRR AND RAP FCST SOUNDING SOLNS SHOW THIS LOW LEVEL
MOISTURE MOVING BACK IN...WHILE THE GFS/NAM DRY IT OUT. HAVE
TRENDED FCST TOWARD MORE CLOUDS WITH THE BEST PERCENTAGES ACRS THE
NORTH. WHERE MORE CLEARING IS LKLY (ACRS THE SOUTH) A BETTER
CHANCE FOR FOG DEVELOPMENT WILL OCCUR.
HAVE ADJUSTED TEMPERATURES ALLOWING FOR MORE CLOUDS WITH LOWS
GENERALLY IN THE MID AND UPPER 20S.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH SATURDAY NIGHT/...
MID LEVEL RIDGE TO BUILD EAST BECOMING CENTERED OVER THE REGION
BY FRIDAY EVENING. SURFACE HIGH PRESSURE TO BUILD ACRS THE AREA
DURG THE DAY. EXPECT ANY CLOUDS OR FOG TO GIVE WAY TO INCREASING
SUNSHINE AFTER MID MORNING. AFTER A SEASONABLY COOL START TO THE
DAY...TEMPERATURES WILL WARM TO HIGHS FROM THE MID 40S NORTH TO
THE UPPER 40S SOUTH.
THE MID LEVEL RIDGE WILL CONTINUE TO BUILD SLOWLY EAST ACRS THE
GREAT LAKES SATURDAY. DRY WEATHER TO CONTINUE WITH SUBSIDENCE OVER
THE AREA. EXPECT FRIDAY NIGHTS LOWS A LTL BELOW NORMAL...IN THE
MID AND UPPER 20S.
ON THE BACK SIDE OF SURFACE HIGH PRESSURE A SOUTHERLY FLOW WILL
BEGIN TO DEVELOP SATURDAY. SKIES TO REMAIN MAINLY CLEAR WITH ONLY
SOME INCREASE IN HIGH LEVEL CLOUDS SATURDAY NIGHT. TEMPERATURES
WILL CONTINUE TO MODERATE IN LOW LEVEL SOUTHERLY FLOW REGIME.
EXPECT HIGHS SATURDAY GENERALLY IN THE LOWER 50S. LOWS SATURDAY
NIGHT WILL BE AROUND 30.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
EXPECT INCREASING CLOUDS SUNDAY AHEAD OF A CLOSED UPPER LOW. SHOWERS
MAY BRUSH SOUTHERN COUNTIES SUNDAY NIGHT THROUGH MONDAY MORNING WHEN
THE UPPER LOW IS FORECAST TO TRAVEL ACROSS OHIO. LOOK FOR DRY
CONDITIONS TO RETURN WITH HIGH PRESSURE TUESDAY AND WEDNESDAY.
LATEST ECMWF RUN SHOWS A TROUGH OF LOW PRESSURE AND ASSOCIATED
MOISTURE ARRIVING THURSDAY. WENT WITH A SLIGHT CHANCE OF SHOWERS IN
SOUTHERN COUNTIES AND WILL WAIT FOR LATER MODEL RUNS TO REFINE THE
FORECAST WITH RESPECT TO THIS SYSTEM.
PATTERN FEATURING ABOVE AVERAGE GEOPOTENTIAL HEIGHTS POINTS TO ABOVE
NORMAL TEMPERATURES. HIGH TEMPERATURES WILL HOVER AROUND THE UPPER
40S...WHILE NORMAL HIGHS FOR THE PERIOD ARE IN THE LOW TO MID 40S.
&&
.AVIATION /00Z FRIDAY THROUGH TUESDAY/...
MVFR CLOUDS OVER THE REGION ARE EXPECTED TO GENERALLY REMAIN IN
PLACE TONIGHT. THESE CLOUDS ARE VERY SLOWLY ERODING FROM SOUTHWEST
TO NORTHEAST...AND THE CINCINNATI TAF SITES ARE LIKELY TO SEE THE
CLOUDS SCATTER OUT TO VFR OVER THE NEXT FEW HOURS. FOR THE
DAYTON AND COLUMBUS TAF SITES...THE CLOUDS ARE UNLIKELY TO BREAK
UP UNTIL FRIDAY MORNING. THE CLOUDS MAY DROP BELOW 2000 FEET AT
TIMES...AND THERE IS A SLIGHT CHANCE OF SOME IFR CEILINGS. THERE
IS ALSO A CHANCE THAT AN OCCASIONAL BREAK IN THE CLOUDS WILL ALLOW
FOR BRIEF CLEAR SKIES...BUT THESE WILL NOT BE THE PREVAILING
CONDITIONS.
THE CLOUDS ARE LIKELY TO SCATTER OUT ON FRIDAY MORNING...LEAVING
CLEARING CONDITIONS AND VFR TAFS THROUGH THE END OF THE PERIOD.
WINDS WILL REMAIN GENERALLY WESTERLY AT LESS THAN 10 KNOTS.
OUTLOOK...NO SIGNIFICANT WEATHER IS EXPECTED.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...AR
NEAR TERM...HICKMAN/AR
SHORT TERM...AR
LONG TERM...CONIGLIO
AVIATION...HATZOS
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
338 PM EST THU DEC 3 2015
.SYNOPSIS...
CLOUDS WILL LINGER ACROSS PORTIONS OF THE AREA TONIGHT AS AN
UPPER LEVEL LOW CONTINUES TO MOVE AWAY FROM THE REGION. HIGH
PRESSURE WILL BECOME ESTABLISHED IN THE OHIO VALLEY BY FRIDAY...
WHICH WILL PROVIDE ABUNDANT SUNSHINE AND ALLOW FOR TEMPERATURES TO
MODERATE THROUGH THE UPCOMING WEEKEND. A WEAK AREA OF LOW PRESSURE
WILL APPROACH THE AREA BY EARLY MONDAY...OFFERING THE NEXT CHANCE
OF RAIN.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
NORTHWEST FLOW ALOFT WILL DOMINATE AS UPPER LEVEL LOW CONTINUES TO
TRANSLATE EAST INTO NEW ENGLAND. SURFACE HIGH PRESSURE OVER THE
PLAINS TO BUILD EAST BECOMING CENTERED OVER THE OHIO VALLEY BY 12Z
FRIDAY. A GOOD DEAL OF LOW LEVEL MOISTURE LINGERS ACROSS THE AREA.
LATEST VISIBLE SATL SHOWS MOST OF ILN/S COVERED BY LOW CLOUDS.
MORE BREAKS AND DRYING SHOWING UP ACRS PORTIONS OF SOUTHERN AND
EASTERN INDIANA. ADDITIONAL MOISTURE OVER ILLINOIS MOVING INTO
INDIANA. HRRR AND RAP FCST SOUNDING SOLNS SHOW THIS LOW LEVEL
MOISTURE MOVING BACK IN...WHILE THE GFS/NAM DRY IT OUT. HAVE
TRENDED FCST TOWARD MORE CLOUDS WITH THE BEST PERCENTAGES ACRS THE
NORTH. WHERE MORE CLEARING IS LKLY (ACRS THE SOUTH) A BETTER
CHANCE FOR FOG DEVELOPMENT WILL OCCUR.
HAVE ADJUSTED TEMPERATURES ALLOWING FOR MORE CLOUDS WITH LOWS
GENERALLY IN THE MID AND UPPER 20S.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH SATURDAY NIGHT/...
MID LEVEL RIDGE TO BUILD EAST BECOMING CENTERED OVER THE REGION
BY FRIDAY EVENING. SURFACE HIGH PRESSURE TO BUILD ACRS THE AREA
DURG THE DAY. EXPECT ANY CLOUDS OR FOG TO GIVE WAY TO INCREASING
SUNSHINE AFTER MID MORNING. AFTER A SEASONABLY COOL START TO THE
DAY...TEMPERATURES WILL WARM TO HIGHS FROM THE MID 40S NORTH TO
THE UPPER 40S SOUTH.
THE MID LEVEL RIDGE WILL CONTINUE TO BUILD SLOWLY EAST ACRS THE
GREAT LAKES SATURDAY. DRY WEATHER TO CONTINUE WITH SUBSIDENCE OVER
THE AREA. EXPECT FRIDAY NIGHTS LOWS A LTL BELOW NORMAL...IN THE
MID AND UPPER 20S.
ON THE BACK SIDE OF SURFACE HIGH PRESSURE A SOUTHERLY FLOW WILL
BEGIN TO DEVELOP SATURDAY. SKIES TO REMAIN MAINLY CLEAR WITH ONLY
SOME INCREASE IN HIGH LEVEL CLOUDS SATURDAY NIGHT. TEMPERATURES
WILL CONTINUE TO MODERATE IN LOW LEVEL SOUTHERLY FLOW REGIME.
EXPECT HIGHS SATURDAY GENERALLY IN THE LOWER 50S. LOWS SATURDAY
NIGHT WILL BE AROUND 30.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
EXPECT INCREASING CLOUDS SUNDAY AHEAD OF A CLOSED UPPER LOW. SHOWERS
MAY BRUSH SOUTHERN COUNTIES SUNDAY NIGHT THROUGH MONDAY MORNING WHEN
THE UPPER LOW IS FORECAST TO TRAVEL ACROSS OHIO. LOOK FOR DRY
CONDITIONS TO RETURN WITH HIGH PRESSURE TUESDAY AND WEDNESDAY.
LATEST ECMWF RUN SHOWS A TROUGH OF LOW PRESSURE AND ASSOCIATED
MOISTURE ARRIVING THURSDAY. WENT WITH A SLIGHT CHANCE OF SHOWERS IN
SOUTHERN COUNTIES AND WILL WAIT FOR LATER MODEL RUNS TO REFINE THE
FORECAST WITH RESPECT TO THIS SYSTEM.
PATTERN FEATURING ABOVE AVERAGE GEOPOTENTIAL HEIGHTS POINTS TO ABOVE
NORMAL TEMPERATURES. HIGH TEMPERATURES WILL HOVER AROUND THE UPPER
40S...WHILE NORMAL HIGHS FOR THE PERIOD ARE IN THE LOW TO MID 40S.
&&
.AVIATION /20Z THURSDAY THROUGH TUESDAY/...
AN UPPER LOW OVER THE LOWER GREAT LAKES WILL PUSH OFF TO THE
NORTHEAST TODAY AS SURFACE HIGH PRESSURE BUILDS IN FROM THE
SOUTHWEST. PLENTY OF LOW LEVEL MOISTURE HAS RESULTED IN MVFR
CEILINGS ACROSS MUCH OF THE AREA. SOME DRIER AIR JUST OFF TO OUR
WEST HAS ALLOWED FOR SIGNIFICANT CLEARING OVER PARTS OF ILLINOIS
AND INDIANA...AS WELL AS SOME CLOUD BREAKS OVER OHIO. MODELS ARE
IN GOOD AGREEMENT WITH ADDITIONAL MOISTURE STREAMING SOUTHEAST OFF
THE GREAT LAKES TODAY...WHICH WILL HELP TO MAINTAIN THE MVFR DECK
OVER THE TERMINALS THIS MORNING INTO THE AFTERNOON. HOWEVER THERE
MAY BE SOME BRIEF BREAKS ALLOWING FOR SCATTERED COVERAGE AT TIMES
BUT CONFIDENCE IN TIMING/LOCATION IS LOW AT THIS TIME. AS THE
DRIER AIR TO OUR WEST SETTLES IN LATER THIS AFTERNOON AND
EVENING...EXPECT TO SEE THE CLOUD DECK GRADUALLY LIFT AND SCOUR
OUT FROM WEST TO EAST. SOUTHERN TERMINALS WILL LIKELY CLEAR OVERNIGHT.
WESTERLY WINDS AROUND 10 KNOTS THIS MORNING WILL GRADUALLY DIMINISH
THIS AFTERNOON AND EVENING AS THE HIGH BUILDS IN...WITH WINDS
BECOMING LIGHT AND SHIFTING TO THE SOUTHWEST TONIGHT.
OUTLOOK...NO SIGNIFICANT WEATHER IS EXPECTED.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...AR
NEAR TERM...AR
SHORT TERM...AR
LONG TERM...CONIGLIO
AVIATION...HICKMAN
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
111 AM EST THU DEC 3 2015
.SYNOPSIS...
AN UPPER LEVEL LOW WILL TRACK EAST THROUGH THE REGION
BRINGING A MIX OF RAIN AND SNOW SHOWERS TONIGHT. HIGH PRESSURE WILL
THEN BUILD INTO THE REGION FRIDAY...OFFERING DRY WEATHER WITH A
GRADUALLY WARMING TEMPERATURES GOING INTO THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
A FEW ADJUSTMENTS WERE MADE TO THE FORECAST BASED ON UPSTREAM
OBSERVATIONS IN INDIANA...AND RECENT HRRR GUIDANCE.
THE ILN FORECAST AREA IS CURRENTLY IN A PRECIPITATION LULL...WITH
JUST SOME VERY LIGHT RAIN/DRIZZLE ACROSS THE EASTERN PORTIONS OF
THE CWA...AND A FEW FLURRIES IN THE FAR NORTH. OVER INDIANA...A
WEAK AND SOMEWHAT ILL-DEFINED SURFACE BOUNDARY IS MOVING
SOUTHEAST...UNDER AN AREA OF VERY COLD 850MB/700MB AIR. THIS HAS
ALLOWED A SMALL WINDOW OF OPPORTUNITY FOR VERY STEEP LAPSE RATES
TO COMBINE WITH SOME LOW-LEVEL FORCING...PRODUCING CONVECTIVE SNOW
OVER CENTRAL INDIANA DURING THE PAST HOUR. THE EASTWARD
TRANSLATION OF THIS REGIME WILL CROSS THE ILN CWA BETWEEN 02Z AND
07Z...AND POPS HAVE BEEN INCREASED DURING THIS TIME FRAME
(ESPECIALLY IN THE WESTERN CWA IN THE NEXT FEW HOURS).
THERE ARE SIGNS THAT THE DEGREE OF FORCING AND INSTABILITY WILL
GRADUALLY WEAKEN WITH TIME...SO HEAVIER SNOW SHOWERS ARE NOT
PARTICULARLY LIKELY TO HOLD TOGETHER ALL NIGHT (THE 22Z/23Z HRRR
RUNS INDICATED THIS USING SIMULATED REFLECTIVITY).
NONETHELESS...SOME OF THIS ACTIVITY MAY HOLD TOGETHER INTO THE
WEST-CENTRAL PORTIONS OF THE FORECAST AREA...WHERE SOME LIGHT
ACCUMULATIONS (UNDER A HALF INCH) COULD BE POSSIBLE.
PREVIOUS DISCUSSION >
MID LEVEL LOW OVER THE UPPER MS VLY TO TRANSLATE EAST ACROSS THE
OHIO VALLEY TONIGHT. SCATTERED SHOWERS AND ISOLD THUNDER HAS
DEVELOPED ALONG SFC TROF WHICH IS LEADING EDGE OF PRECIPITATION
AREA MOVING EAST THRU CENTRAL OHIO. THERMAL TROF OVER THE AREA
THIS EVENING WITH -7 DEGREES AT 8H OVERHEAD. THIS WILL ALLOW LOW
LEVEL LAPSE RATES TO STEEPEN LEADING TO ADDITIONAL SCATTERED
SHOWERS. IN LOW LEVEL CAA PATTERN...RAIN SHOWERS TO TRANSITION TO
SNOW SHOWERS FROM WEST TO EAST WITH A PERIOD OF ALL SNOW THIS
EVENING. ANY ACCUMULATION WILL BE VERY LIGHT WITH A MAX OF A TENTH
OR TWO...MAINLY ON GRASSY AREAS. EXPECT CONSIDERABLE CLOUDINESS
WITH SOME PARTIAL CLEARING INTO THE SOUTHWEST LATE. EXPECT LOWS
FROM UPPER 20S WEST TO THE LOWER 30S EAST.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH FRIDAY NIGHT/...
MID LEVEL LOW OVER THE EASTERN GREAT LAKES AT 12Z THURSDAY TO
CONTINUE TRANSLATING EAST INTO NEW ENGLAND BY AFTERNOON. SURFACE
HIGH PRESSURE OVER THE PLAINS TO BUILD EAST INTO THE OHIO VALLEY.
AS LOW LEVEL FLOW TRANSITIONS FROM CYCLONIC TO ANTI-CYCLONIC...CLOUDS
WILL GIVE WAY TO SUNSHINE. TEMPERATURES WILL BE A LTL COOLER THAN
NORMAL WITH HIGHS GENERALLY IN THE LOWER 40S.
SURFACE HIGH PRESSURE WILL BECOME CENTERED OVER THE OHIO VALLEY
FRIDAY MORNING. EXPECT SKIES TO CLEAR OUT WITH SEASONABLY COLD
TEMPERATURES. LOWS BY FRIDAY MORNING WITH BE IN THE MID AND UPPER
20S.
UNDER THE INFLUENCE OF SFC HIGH PRESSURE EXPECT A GOOD AMOUNT OF
SUNSHINE...WITH HIGHS AT OR SLIGHTLY ABOVE NORMAL IN THE MID/UPPER
40S.
GENERALLY CLEAR SKIES FRIDAY NIGHT WITH ONLY SOME THIN HIGH LEVEL
CLOUDS. LOWS FRIDAY NIGHT EXPECTED TO BE IN THE MID AND UPPER 20S.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
SATURDAY WILL BE DRY WITH SURFACE HIGH PRESSURE CENTERED ALONG THE
EAST COAST. LOOK FOR INCREASING CLOUDS ON SUNDAY WHEN A CLOSED UPPER
LOW IS FORECAST TO MOVE TOWARD THE AREA FROM THE WEST. THERE WILL BE
A CHANCE OF SHOWERS MONDAY AND MONDAY NIGHT IN SOUTHERN LOCATIONS
WHEN MODELS SHOW THE UPPER LOW TRAVELING THROUGH KENTUCKY. DRY
WEATHER IS THEN INDICATED FOR TUESDAY AND WEDNESDAY WITH THE RETURN
OF HIGH PRESSURE.
OVERALL PATTERN FEATURING AN UPPER RIDGE AND HIGHER THAN AVERAGE
GEOPOTENTIAL HEIGHTS WILL FAVOR ABOVE NORMAL TEMPERATURES. HIGHS
SATURDAY AND SUNDAY MAINLY IN THE LOWER 50S WILL SLIP SLIGHTLY TO
THE MID AND UPPER 40S FOR MONDAY THROUGH WEDNESDAY. NORMAL HIGHS
WILL BE IN THE LOW TO MID 40S.
&&
.AVIATION /06Z THURSDAY THROUGH MONDAY/...
AN UPPER LOW OVER THE LOWER GREAT LAKES WILL DRIFT EASTWARD
OVERNIGHT WHILE A WEAK SURFACE TROUGH PUSHES THROUGH THE AREA.
EXPECT SNOW SHOWER ACTIVITY TO MOVE OUT OF THE COLUMBUS AND
WILMINGTON AREAS WITHIN THE FIRST HOUR OF THE TAF PERIOD.
REGIONAL RADAR DOES SHOW SOME LIGHT LAKE EFFECT SNOW SHOWERS
STREAMING SOUTHEAST OFF LAKE MICHIGAN. HI-RES MODELS ARE NOT
CAPTURING THIS ACTIVITY VERY WELL...BUT CURRENT TRAJECTORY WOULD
SUGGEST THESE MAY MOVE INTO THE AREA WITHIN THE NEXT FEW HOURS. IF
THIS OCCURS...WOULD JUST EXPECT SOME FLURRIES AT KDAY/KILN AND
POSSIBLY THE CINCINNATI TERMINALS BUT CONFIDENCE IN THIS IS NOT
PARTICULARLY HIGH.
CEILINGS ARE THE OTHER FORECAST CONCERN FOR THE REST OF TONIGHT.
LATEST SATELLITE REVEALS SOME SIGNIFICANT AREAS OF CLEARING OVER
ILLINOIS AND PARTS OF INDIANA...WHILE THE REST OF THE REGION IS
GENERALLY UNDER MVFR CIGS. WITH ADDITIONAL MVFR CLOUDS STREAMING
OFF OF LAKE MICHIGAN...DO NOT EXPECT ANY SIGNIFICANT CLEARING TO
MOVE INTO OUR AREA THE REST OF TONIGHT BUT CANNOT RULE OUT SOME
BRIEF CLEARING OR SCATTERING. MODEL GUIDANCE SUPPORTS THIS
THINKING AS WELL. THESE LOW CLOUDS ARE NOT EXPECTED TO LIFT
QUICKLY ON THURSDAY...AND THE CLOUD DECK MAY NOT BREAK UNTIL WELL
INTO THE AFTERNOON. HOWEVER AS HIGH PRESSURE BUILDS IN BY
THURSDAY EVENING SKIES WILL TURN SKC. WESTERLY WINDS WILL REMAIN
IN THE 10-15 KNOT RANGE THROUGH THE REST OF TONIGHT...DIMINISHING
BY THURSDAY AFTERNOON/EVENING.
OUTLOOK...NO SIGNIFICANT WEATHER IS EXPECTED.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...AR
NEAR TERM...HATZOS
SHORT TERM...AR
LONG TERM...CONIGLIO
AVIATION...KURZ
AREA FORECAST DISCUSSION
NWS PORTLAND OR
1041 AM PST THU DEC 3 2015
.SYNOPSIS...A WARM FRONT LIFTING NORTH OF THE REGION THIS MORNING. A
STRONG LOW IS DEVELOPING ALONG THE MAIN FRONTAL BAND OFF THE OREGON
COAST THIS MORNING AND WILL MOVE NORTH AND ONSHORE ALONG THE WESTERN
WASHINGTON COAST LATER TODAY AND THIS EVENING...PRODUCING MORE
RAIN...AREAS OF STRONG WINDS ESPECIALLY ALONG THE COAST AND COASTAL
MOUNTAINS AND LOCALLY INLAND. THE COOLER ASSOCIATED UPPER TROUGH WILL
MOVE THROUGH THE PACIFIC NORTHWEST TONIGHT AND FRIDAY WITH SOME SNOW
IN THE CASCADES AND THUNDERSTORMS NEAR THE COAST. ANOTHER STRONG
FRONTAL SYSTEM WILL BRING MORE RAIN AND WIND TO THE AREA THIS
WEEKEND...FOLLOWED BY ANOTHER EARLY NEXT WEEK.
&&
.SHORT TERM...TODAY THROUGH SATURDAY...A WARM FRONT LIFTED NORTH THE
REGION OVERNIGHT. THIS BROUGHT A ROUND OF STEADY RAIN FOR MOST...WITH
ADDITIONAL SLEET AND FREEZING RAIN IN THE COLUMBIA RIVER GORGE AND
UPPER HOOD RIVER VALLEY. ADDITIONAL LIGHT PRECIPITATION WILL OCCUR
THROUGH THE MORNING AND EARLY AFTERNOON. TEMPERATURES IN THE GORGE
AND UPPER HOOD RIVER VALLEY REMAIN NEAR FREEZING AT THIS TIME...SO
EXPECT ADDITIONAL LIGHT ICING IN THESE AREAS THROUGH EARLY AFTERNOON.
HOWEVER...SINCE PRECIPITATION INTENSITY HAS DROPPED OFF CONSIDERABLY
THIS MORNING...HAVE DROPPED THE ICE STORM WARNING AND REPLACED IT
WITH A FREEZING RAIN ADVISORY. EXPECT TEMPERATURES TO FINALLY WARM
ABOVE FREEZING LATER THIS AFTERNOON...FINALLY ENDING THE FREEZING
RAIN THREAT.
THE MAIN COLD FRONT HAS PIVOTED TO A NORTH TO SOUTH ORIENTATION JUST
OFFSHORE DUE TO THE DEVELOPMENT OF A SECONDARY LOW ALONG THE
BAROCLINIC ZONE OFF OF THE SOUTHERN OREGON COAST. THIS SECONDARY LOW
WILL LIFT NORTH ALONG THE COAST TROUGH THE DAY...MAKING LANDFALL
ALONG THE WESTERN WASHINGTON COAST LATER THIS AFTERNOON. THERE HAS
BEEN MODEL UNCERTAINTY ON EXACTLY WHAT TRACK THE LOW WILL TAKE AND
WHERE IT WILL MAKE LANDFALL...WHICH HAS MADE FORECASTING THE
ASSOCIATED WINDS SOMEWHAT DIFFICULT. THE 17Z HRRR AND 12Z UW WRF-GFS
RUNS ARE NOW INDICATING THAT THE LOW WILL MOVE INLAND NEAR
QUILLAYUTE...WHICH IS A BIT FURTHER NORTH THAN THE PREVIOUS FORECAST
WAS ANTICIPATING. AS A RESULT...THINK THAT WINDS WILL NOT BE QUITE AS
STRONG OVER THE INTERIOR LOWLANDS AND HAVE DECIDED TO DOWNGRADE THE
HIGH WIND WATCH FOR THE INTERIOR I-5 CORRIDOR IN COWLITZ COUNTY AND
THE SOUTH WASHINGTON CASCADE FOOTHILLS. WILL STILL KEEP A WIND
ADVISORY FOR THE INTERIOR...INCLUDING THE I-5 CORRIDOR IN SW
WASHINGTON AND ALL OF THE WILLAMETTE VALLEY. EXPECT THE STRONGEST
WINDS TO BE FURTHEST NORTH...AND A BIT WEAKER DOWN IN THE CENTRAL AND
ESPECIALLY THE SOUTHERN WILLAMETTE VALLEY. A HIGH WIND WARNING IS IN
EFFECT FOR ALL OF THE COAST AND COAST RANGE ZONES...INCLUDING THE
WILLAPA HILLS. EXPECT WIND GUSTS OF 55 TO 65 MPH TO BEGIN TO SURFACE
ALONG THE CENTRAL OREGON COAST OVER THE NEXT COUPLE OF HOURS...WITH
STRONG WINDS PROGRESSING FURTHER NORTH THIS AFTERNOON AS THE LOW
LIFTS NORTHWARD.
THE COLD FRONT WILL MOVE THROUGH THE REGION LATE THIS AFTERNOON AND
THIS EVENING...BRINGING A PERIOD OF STEADIER PRECIPITATION. THE FRONT
SHOULD ALSO FINALLY SCOUR THE COLD AIR FROM THE EAST SIDE OF THE
CASCADES AND ALLOW THE SURFACE GRADIENT THROUGH THE GORGE FROM
EASTERLY TO WESTERLY. THE ASSOCIATED UPPER TROUGH MOVES THROUGH
TONIGHT AND FRIDAY. IT HAS SOME COOLER AIR ASSOCIATED WITH IT...AND
SNOW LEVELS WILL FALL BELOW CASCADE PASS ELEVATIONS TONIGHT AND
FRIDAY. THERE COULD BE SEVERAL INCHES OF SNOW TONIGHT AND FRIDAY IN
THE CASCADES...BUT THE ONSHORE FLOW DOES NOT STAY SUSTAINED LONG
ENOUGH SO THERE MAY NOT QUITE BE ENOUGH SNOW FOR A SNOW
ADVISORY...BUT IT COULD GET CLOSE NORTH. ALSO...WITH THE COLDER AIR
ALOFT MAY SEE SOME THUNDER TONIGHT AND FRIDAY MORNING OVER THE
COASTAL WATERS AND ALONG THE COAST.
ANOTHER MOIST FRONT WITH HIGHER SNOW LEVELS COMES IN THE NORTH PART
OF OUR FORECAST SATURDAY AND THE REMAINDER OF THE AREA SATURDAY NIGHT
WITH ANOTHER GOOD SHOT OF RAIN AND WIND. PYLE
.LONG TERM...NO CHANGES. PREVIOUS DISCUSSION FOLLOWS...SATURDAY NIGHT
THROUGH TUESDAY...ACTIVE WEATHER PATTERN CONTINUES THROUGH THE
WEEKEND INTO EARLY NEXT WEEK...WITH A NEW SYSTEM APPROXIMATELY EVERY
24 HRS. SIGNIFICANT RAINFALL EXPECTED TO ACCUMULATE OVER THE WEEKEND
INTO EARLY NEXT WEEK...ESPECIALLY ALONG THE SOUTH WASHINGTON AND FAR
NORTH OREGON COAST. FLOODING SEEMS LIKELY TO BE A CONCERN AT LEAST
ALONG THE SOUTH WASHINGTON AND FAR NORTH OREGON COAST DUE TO LITTLE
DOWN TIME BETWEEN THESE SYSTEMS AND THE HIGHEST ACCUMULATIONS
CONTINUING TO BE OVER THIS SAME AREA.
SATURDAY`S SYSTEM TAPS INTO TROPICAL MOISTURE...BUT THE BULK OF THE
PRECIPITATION RIGHT NOW IS AIMED TO OUR NORTH...WITH HIGHEST
ACCUMULATIONS IN OUR AREA STAYING ALONG THE SOUTH WASHINGTON AND FAR
NORTH OREGON COAST AND COAST RANGE...AND MAYBE THE SOUTH WASHINGTON
CASCADES AS WELL. CONFIDENCE IS MODERATE IN THIS TRACK DUE TO GOOD
MODEL AGREEMENT...BUT THERE IS STILL A CHANCE THIS TRACK COULD SHIFT
SOUTHWARD AS THE SYSTEM MOVES CLOSER. WINDY CONDITIONS ARE EXPECTED
ALONG THE COAST WITH THIS SYSTEM AS WELL...MAINLY MIDDAY SATURDAY
AHEAD OF THE FRONT MOVING THROUGH LATE SATURDAY NIGHT. SUNDAY SHOULD
BE A BIT DRIER WITH A FEW POST-FRONTAL SHOWERS STILL LINGERING AROUND
THE AREA THROUGH THE DAY. SNOW LEVELS COME DOWN FOR SUNDAY WHICH
COULD BRING SOME SNOW TO THE PASSES. OUR NEXT SYSTEM BRINGS SNOW
LEVELS BACK UP ABOVE THE PASSES EARLY MONDAY WITH RAIN ALL DAY.
MODELS START TO DIVERGE ON TIMING WITH THESE SYSTEMS EARLY NEXT
WEEK...BUT PATTERN OF A NEW SYSTEM EVERY 24 HOURS SEEMS LIKELY TO
CONTINUE THROUGH AT LEAST MIDWEEK. -MCCOY
&&
.AVIATION...GENERALLY VFR CIGS ACROSS THE REGION THIS MORNING WITH
LINGERING SHOWERS INLAND BEHIND THE WARM FRONT THAT HAS MOVED INTO
SOUTHERN WASHINGTON. LITTLE CHANGE NEXT FEW HOURS IN THE WARM
SECTOR...THOUGH COLD FRONT JUST OFF THE WA/OR COAST AS OF 18Z WILL
CONTINUE TO SLIDE INLAND THIS AFTERNOON. EXPECT LOWERING CIGS TO
AROUND 2500 FT BY EVENING...AND POSSIBLE VSBY RESTRICTIONS IN RAIN.
E WINDS ONGOING THROUGH GORGE AND INTO EASTERN PDX METRO AREA...BUT
STRONG S WINDS DEVELOP ALONG COAST AND COAST RANGE WITH GUSTS TO 45-
55 KT...AND GUSTY S WINDS TO 35 KT ALSO DEVELOPING ACROSS INTERIOR.
WINDS EASE THIS EVENING...GENERALLY IN THE SOUTH FIRST AND THEN THE
NORTH A FEW HOURS LATER. EXPECT WIDESPREAD MVFR CIGS WITH LOCAL IFR
POCKETS TONIGHT...AND ONGOING SHOWERS.
KPDX AND APPROACHES...VFR CIGS CONTINUE THIS MORNING WITH GUSTY E
WINDS. INTRODUCED LLWS TO TAF WITH STRONG S WINDS AT 2000 FT AND
GUSTY E AT THE SURFACE...A COMBINATION OF SPEED AND DIRECTIONAL
SHEAR TO GET CLOSE OR MEET THRESHOLD. HOWEVER...SFC WINDS SHIFT FROM
E TO S AROUND 21-22Z BUT REMAIN GUSTY TO 25-35 KT THROUGH AROUND
03Z. FRONT BRINGS LOWERING MVFR CIGS...RAIN...AND POSSIBLE VSBY
RESTRICTIONS WITH ONGOING SHOWERS THROUGH THE NIGHT. CULLEN
&&
.MARINE...STRONG WINDS WILL CONTINUE THIS AFTERNOON AS A STRONG
SURFACE LOW MOVES SOUTH TO NORTH ACROSS THE WATERS. BUOY 89
REPORTED 50 KT GUSTS EARLIER THIS MORNING WITH 26 FT SEAS. THE
BEST CHANCE FOR SIMILAR CONDITIONS TO REACH THE INNER WATERS IS
FOR THIS AFTERNOON. THE WAY THE LOW IS TRACKING THINK THE NORTHERN
INNER WATERS ARE MORE SUSCEPTIBLE TO SEE THIS BURST OF EXTRA HIGH
WINDS AND SEAS THAN THE SOUTHERN. THE WINDS WILL BE VEERING WITH
WEST DURING THIS TIME. THE WINDS AND SEAS MAY LOWER QUICKER ACROSS
THE SOUTH THAN THE CURRENT FORECAST SUGGESTS.
WILL HAVE A BREAK BETWEEN STORMS FRIDAY AND WINDS WILL FALL BELOW
ADVISORY LEVELS. A LONG PERIOD W-NW SWELL WILL MOVE THROUGH THE
WATERS FRIDAY. THE OFFSHORE BUOYS 46004 AND 46036 ARE DETECTING
THIS SWELL WITH OBSERVATIONS AROUND 17 FT AT 15 SECONDS. THIS
SWELL WILL DECAY TO AROUND 13 FT AT 16 SECONDS WHEN IT REACHES
THE OREGON WATERS LATE FRIDAY MORNING.
THE NEXT FRONT IS VERY STRONG AND HAS GREAT POTENTIAL FOR
WIDESPREAD GALES FRIDAY NIGHT...INTENSIFYING TO STORM FORCE GUSTS
SATURDAY MORNING. SEAS WILL RISE TO ABOVE 20 FT WITH THIS FRONT
SATURDAY AND SATURDAY NIGHT.
&&
.PQR WATCHES/WARNINGS/ADVISORIES...
OR...FREEZING RAIN ADVISORY UNTIL 3 PM PST THIS AFTERNOON FOR
CENTRAL COLUMBIA RIVER GORGE-UPPER HOOD RIVER VALLEY-WESTERN
COLUMBIA RIVER GORGE.
WIND ADVISORY UNTIL 7 PM PST THIS EVENING FOR GREATER PORTLAND
METRO AREA-LOWER COLUMBIA.
HIGH WIND WARNING UNTIL 6 PM PST THIS EVENING FOR CENTRAL
OREGON COAST-NORTH OREGON COAST.
WIND ADVISORY UNTIL 7 PM PST THIS EVENING FOR CENTRAL
WILLAMETTE VALLEY-SOUTH WILLAMETTE VALLEY.
HIGH WIND WARNING UNTIL 6 PM PST THIS EVENING FOR CENTRAL COAST
RANGE OF WESTERN OREGON-COAST RANGE OF NORTHWEST OREGON.
WA...FREEZING RAIN ADVISORY UNTIL 3 PM PST THIS AFTERNOON FOR
CENTRAL COLUMBIA RIVER GORGE-WESTERN COLUMBIA RIVER GORGE.
WIND ADVISORY UNTIL 7 PM PST THIS EVENING FOR GREATER VANCOUVER
AREA-I-5 CORRIDOR IN COWLITZ COUNTY.
HIGH WIND WARNING UNTIL 7 PM PST THIS EVENING FOR SOUTH
WASHINGTON COAST-WILLAPA HILLS.
PZ...STORM WARNING UNTIL 7 PM PST THIS EVENING FOR COASTAL WATERS
FROM CAPE SHOALWATER WA TO CASCADE HEAD OR OUT 60 NM.
STORM WARNING UNTIL 4 PM PST THIS AFTERNOON FOR COASTAL WATERS
FROM CASCADE HEAD OR TO FLORENCE OR OUT 60 NM.
SMALL CRAFT ADVISORY FOR ROUGH COLUMBIA RIVER BAR UNTIL 1 AM
PST FRIDAY.
$$
INTERACT WITH US VIA SOCIAL MEDIA
WWW.FACEBOOK.COM/NWSPORTLAND
WWW.TWITTER.COM/NWSPORTLAND
THIS DISCUSSION IS FOR NORTHWEST OREGON AND SOUTHWEST WASHINGTON
FROM THE CASCADE CREST TO 60 NAUTICAL MILES OFFSHORE. THE AREA IS
COMMONLY REFERRED TO AS THE FORECAST AREA.
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
156 AM EST THU DEC 3 2015
.SYNOPSIS...
AN UPPER LOW WILL MOVE THROUGH THE REGION OVERNIGHT AND LIFT OUT
TO OUR NORTHEAST LATER TODAY. A RIDGE OF HIGH PRESSURE WILL BUILD
ACROSS THE EASTERN CONUS FOR THE WEEKEND SUPPLYING FAIR AND
MILDER WEATHER.
&&
.NEAR TERM /UNTIL 9 AM THIS MORNING/...
1 AM UPDATE...
BAND OF PRECIP TO THE NE/N OF THE UPPER LOW CIRCULATION IS
PIVOTING OVER LE...BUT LATEST RADAR TRENDS SHOW THAT WE HAVE
NOTHING TO DREAD RE GOING FCST OF A LIGHT SNOW ACCUM FOR THE NW
THIRD AND THE LAURELS. THE TEMPS ARE COLD ENOUGH NOW OVER MOST OF
THE WEST TO MAKE IT ALL SNOW FOR THE REST OF THE EVENT ON THE
HIGH ELEVATIONS AND A RAIN-WET SNOW MIX IN THE VALLEYS. BUT MOST
PLACES N/W OF UNV WILL SEE SNOW FALL SOMETIME OVERNIGHT. TEMPS
HAVE ONLY JUST GONE TO FREEZING AT SOMERSET AIRPORT/K2G9...WITH NO
OTHER SITES YET TO GO FROZEN. LATEST NAM/HRRR/RAP FCSTS PLAY A
LITTLE BIT OF A WAGGLE TO THE NORTH WITH THE SNOW BAND IN THE
NORTH. HAVE JUST NUDGED THINGS A BIT FARTHER TO THE NORTH THRU THE
PERIOD. BUT ACCUMS SHOULD REMAIN 2 INCHES OR BELOW SINCE THE TEMPS
ARE SO MARGINAL.
PREV...
A SURFACE TROUGH/SECONDARY COLD FRONT EXTENDS FROM THE LOW NEAR
ALBANY NY BACK THROUGH NRN PA INTO MICHIGAN JUST NORTH OF DETROIT.
THE CORE OF THE COLD AIR ASSOCIATED WITH THE UPPER LOW EXTENDS
FROM WESTERN OHIO INTO IN/IL. THIS WILL TRANSLATE EAST OVERNIGHT
AS THE DEEP UPPER LOW MOVES QUICKLY TOWARD WESTERN PA AND NY.
RADAR SHOWS A SMALL BUT SLOWLY EVOLVING AREA OF RAIN SHOWERS FROM
NW PA DOWN INTO WESTERN CLEARFIELD COUNTY. IT APPEARS TO BE
ASSOCIATED WITH AN AREA OF MID LEVEL DEFORMATION/FRONTOGENETIC
FORCING THAT THE HRRR AND RAP SHOW CONTINUING TO DEVELOP AS IT
PIVOTS THROUGH MAINLY MY NWRN ZONES THROUGHOUT THE
OVERNIGHT...WITH THE BEST ORGANIZATION INDICATED AFTER MIDNIGHT
THROUGH ABOUT SUNRISE.
AS COLDER AIR ARRIVES LATER THIS EVENING AND INTO THE WEE HOURS
OF THURSDAY...THE LIGHT RAIN SHOWERS WILL TURN TO SNOW SHOWERS
OVER THE WEST BEFORE SPREADING EAST INTO THE CENTRAL MOUNTAINS.
A BLEND OF MODEL QPFS YIELDS SNOWFALLS IN THE 1-3 INCH RANGE
WHICH MAY BE TOO HIGH GIVEN THAT A CHANGEOVER TO SNOW WAS
EXPECTED TO HAVE OCCURRED BY NOW. WE DIDN`T CHANGE THE FORECAST
MUCH AND STUCK WITH WITH 1-2 INCHES ACROSS THE NW MTNS AND LAUREL
HIGHLANDS...WITH A COATING TO 1/2 INCH POSSIBLE EVEN ACROSS THE
CENTRAL RIDGE AND VALLEY REGION AFTER 06Z. WE DID BACK OFF THE
ADMITTEDLY SMALL AMOUNTS WE HAD FOR THE LOWER SUSQ AS LATEST
GUIDANCE IS STINGY WITH THE QPF ONCE THE SYSTEM EMERGES EAST OF
THE CENTRAL MOUNTAINS.
LOW TEMPS WILL BE 30 ACROSS THE HIGH TERRAIN OF THE NORTH AND
WEST TO NEAR 40F IN THE LOWER SUSQ VALLEY.
&&
.SHORT TERM /9 AM THIS MORNING THROUGH 6 PM FRIDAY/...
THE UPPER TROUGH AXIS WILL SLIDE ACROSS THE REGION DURING THE
MORNING AND MIDDAY HOURS THURSDAY...ACCOMPANIED BY PLENTY OF
CLOUDS ACROSS THE CENTRAL AND NW MTNS...WHILE PERIODS OF SUNSHINE
WILL DEVELOP ACROSS THE FAVORED DOWNSLOPE REGION OF THE SUSQ
VALLEY AND SCENT PENN.
SNOW SHOWER COVERAGE WILL GRADUALLY DECREASE DURING THE
AFTERNOON AND BECOME CONFINED TO THE MOST FAVORED UPSLOPE AREAS
OF THE LAURELS AND NW MOUNTAINS IN THE WAKE OF THE DEPARTING LOW.
ADDITIONAL SNOW ACCUMS THURSDAY WILL BE LESS THAN ONE INCH IN MOST
PLACES ACROSS NW PA AND THE LAURELS...WITH JUST FLURRIES AND
BRIEF SNOW SHOWERS ACROSS THE CENTRAL RIDGE AND VALLEY REGION.
HIGH TEMPS THURSDAY WILL RANGE FROM THE MID-UPPER 30S ACROSS THE
NRN AND WRN MTNS TO THE UPPER 40S IN THE SE.
&&
.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
A SPLIT FLOW PATTERN IS FCST OVER THE LOWER 48 THRU THE MEDIUM
RANGE PERIOD...WITH RATHER MILD TEMPERATURES FOR EARLY DECEMBER
ANTICIPATED AS A PACIFIC AIRMASS MIGRATES FROM WEST TO EAST.
RIDGING AT THE SURFACE AND ALOFT WILL DOMINATE THE REGIONAL
WEATHER PATTERN WITH HIGH CONFIDENCE IN DRY WEATHER THROUGH
MONDAY.
THE KEY FEATURE HEADING INTO THE MIDDLE OF NEXT WEEK WILL BE A
MID LEVEL SYSTEM EVOLVING EASTWARD FROM THE ROCKIES AND POSSIBLY
CUTTING OFF SOMEWHERE BETWEEN TEXAS AND THE OHIO VALLEY. GIVEN THE
LARGE SPREAD AND MEDIUM RANGE MODEL `LIMBO` WILL STAY CLOSE TO
CONTINUITY AND SHOW A MODEST INCREASE IN POPS TOWARD CLIMO BY DAY
7-8. THAT SAID...THE PATTERN MAY VERY WELL REMAIN A DRY ONE
THROUGH THE ENTIRE PERIOD. CONFIDENCE IS LOW REGARDING PCPN RISK
AROUND THE MIDDLE PART OF NEXT WEEK.
&&
.AVIATION /07Z THURSDAY THROUGH MONDAY/...
LOW PRESSURE OVER OHIO AT 06Z WILL SWING THRU CENTRAL PA EARLY
THIS MORNING...BRINGING A PERIOD OF SNOW/LOW CIGS TO THE W MTNS.
UPSTREAM RADAR/SFC OBS...COMBINED WITH NEAR TERM MDL DATA SUGGEST
KBFD WILL BEAR THE BRUNT OF THIS SYSTEM WITH IFR/LIFR CONDS IN
SNOW/LOW CIGS BTWN 06Z-13Z. FURTHER SOUTH...KJST REPORTING LIFR
CONDS IN SNOW AT 06Z. HOWEVER...A TRAILING COLD FRONT WILL PUSH
THRU ARND 08Z...WHICH WILL BE FOLLOWED BY DIMINISHING SNOW/RISING
CIGS AND GUSTY WEST WINDS. BUKFIT AND LAMP GUIDANCE BOTH SUPPORT
GUSTS TO NR 25KTS AT KJST AFTER 08Z...WHICH SHOULD LAST THRU THIS
AFTERNOON. A DOWNSLOPING/DRYING WEST WIND SHOULD RESULT IN MUCH
MORE FAVORABLE FLYING CONDS EAST OF THE ALLEGHENY MTNS THIS AM.
MDL SOUNDINGS IMPLY BRIEF MVFR CIGS POSS AT KUNV/KAOO BTWN 07Z-09Z
AND AT KIPT BTWN 10Z-14Z. FURTHER SE...HIGH CONFIDENCE IN VFR
CONDS AT KMDT/KLNS.
THE LOW PRES SYSTEM WILL LIFT NE TOWARD NEW ENGLAND BY LATE
AM...BRINGING DIMINISHING LGT SNOW/RISING CIGS AT KBFD. RESIDUAL
LOW LVL MOISTURE ASCENDING THE MTNS SHOULD RESULT IN PERSISTENT
MVFR CIGS AT KBFD/KJST THRU THIS EVENING. FURTHER EAST...VFR CIGS
EXPECTED. A TIGHT PRES GRADIENT IN WAKE OF DEPARTING STORM SYSTEM
WILL CREATE GUSTY WNW WINDS ACROSS THE ENTIRE REGION TODAY. BUKFIT
SOUNDINGS INDICATE 20-25KT GUSTS WILL BE COMMON. THE WIND SHOULD
DIMINISH A BIT THIS EVENING...AS HIGH PRES APPROACHES FROM THE
WEST.
OUTLOOK...
FRI-MON...NO SIG WX EXPECTED.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...DANGELO/LA CORTE
NEAR TERM...DANGELO/LA CORTE
SHORT TERM...LAMBERT
LONG TERM...STEINBUGL
AVIATION...FITZGERALD
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
120 AM EST THU DEC 3 2015
.SYNOPSIS...
AN UPPER LOW WILL MOVE THROUGH THE REGION OVERNIGHT AND LIFT OUT
TO OUR NORTHEAST LATER TODAY. A RIDGE OF HIGH PRESSURE WILL BUILD
ACROSS THE EASTERN CONUS FOR THE WEEKEND SUPPLYING FAIR AND
MILDER WEATHER.
&&
.NEAR TERM /UNTIL 9 AM THIS MORNING/...
1 AM UPDATE...
BAND OF PRECIP TO THE NE/N OF THE UPPER LOW CIRCULATION IS
PIVOTING OVER LE...BUT LATEST RADAR TRENDS SHOW THAT WE HAVE
NOTHING TO DREAD RE GOING FCST OF A LIGHT SNOW ACCUM FOR THE NW
THIRD AND THE LAURELS. THE TEMPS ARE COLD ENOUGH NOW OVER MOST OF
THE WEST TO MAKE IT ALL SNOW FOR THE REST OF THE EVENT ON THE
HIGH ELEVATIONS AND A RAIN-WET SNOW MIX IN THE VALLEYS. BUT MOST
PLACES N/W OF UNV WILL SEE SNOW FALL SOMETIME OVERNIGHT. TEMPS
HAVE ONLY JUST GONE TO FREEZING AT SOMERSET AIRPORT/K2G9...WITH NO
OTHER SITES YET TO GO FROZEN. LATEST NAM/HRRR/RAP FCSTS PLAY A
LITTLE BIT OF A WAGGLE TO THE NORTH WITH THE SNOW BAND IN THE
NORTH. HAVE JUST NUDGED THINGS A BIT FARTHER TO THE NORTH THRU THE
PERIOD. BUT ACCUMS SHOULD REMAIN 2 INCHES OR BELOW SINCE THE TEMPS
ARE SO MARGINAL.
PREV...
A SURFACE TROUGH/SECONDARY COLD FRONT EXTENDS FROM THE LOW NEAR
ALBANY NY BACK THROUGH NRN PA INTO MICHIGAN JUST NORTH OF DETROIT.
THE CORE OF THE COLD AIR ASSOCIATED WITH THE UPPER LOW EXTENDS
FROM WESTERN OHIO INTO IN/IL. THIS WILL TRANSLATE EAST OVERNIGHT
AS THE DEEP UPPER LOW MOVES QUICKLY TOWARD WESTERN PA AND NY.
RADAR SHOWS A SMALL BUT SLOWLY EVOLVING AREA OF RAIN SHOWERS FROM
NW PA DOWN INTO WESTERN CLEARFIELD COUNTY. IT APPEARS TO BE
ASSOCIATED WITH AN AREA OF MID LEVEL DEFORMATION/FRONTOGENETIC
FORCING THAT THE HRRR AND RAP SHOW CONTINUING TO DEVELOP AS IT
PIVOTS THROUGH MAINLY MY NWRN ZONES THROUGHOUT THE
OVERNIGHT...WITH THE BEST ORGANIZATION INDICATED AFTER MIDNIGHT
THROUGH ABOUT SUNRISE.
AS COLDER AIR ARRIVES LATER THIS EVENING AND INTO THE WEE HOURS
OF THURSDAY...THE LIGHT RAIN SHOWERS WILL TURN TO SNOW SHOWERS
OVER THE WEST BEFORE SPREADING EAST INTO THE CENTRAL MOUNTAINS.
A BLEND OF MODEL QPFS YIELDS SNOWFALLS IN THE 1-3 INCH RANGE
WHICH MAY BE TOO HIGH GIVEN THAT A CHANGEOVER TO SNOW WAS
EXPECTED TO HAVE OCCURRED BY NOW. WE DIDN`T CHANGE THE FORECAST
MUCH AND STUCK WITH WITH 1-2 INCHES ACROSS THE NW MTNS AND LAUREL
HIGHLANDS...WITH A COATING TO 1/2 INCH POSSIBLE EVEN ACROSS THE
CENTRAL RIDGE AND VALLEY REGION AFTER 06Z. WE DID BACK OFF THE
ADMITTEDLY SMALL AMOUNTS WE HAD FOR THE LOWER SUSQ AS LATEST
GUIDANCE IS STINGY WITH THE QPF ONCE THE SYSTEM EMERGES EAST OF
THE CENTRAL MOUNTAINS.
LOW TEMPS WILL BE 30 ACROSS THE HIGH TERRAIN OF THE NORTH AND
WEST TO NEAR 40F IN THE LOWER SUSQ VALLEY.
&&
.SHORT TERM /9 AM THIS MORNING THROUGH 6 PM FRIDAY/...
THE UPPER TROUGH AXIS WILL SLIDE ACROSS THE REGION DURING THE
MORNING AND MIDDAY HOURS THURSDAY...ACCOMPANIED BY PLENTY OF
CLOUDS ACROSS THE CENTRAL AND NW MTNS...WHILE PERIODS OF SUNSHINE
WILL DEVELOP ACROSS THE FAVORED DOWNSLOPE REGION OF THE SUSQ
VALLEY AND SCENT PENN.
SNOW SHOWER COVERAGE WILL GRADUALLY DECREASE DURING THE
AFTERNOON AND BECOME CONFINED TO THE MOST FAVORED UPSLOPE AREAS
OF THE LAURELS AND NW MOUNTAINS IN THE WAKE OF THE DEPARTING LOW.
ADDITIONAL SNOW ACCUMS THURSDAY WILL BE LESS THAN ONE INCH IN MOST
PLACES ACROSS NW PA AND THE LAURELS...WITH JUST FLURRIES AND
BRIEF SNOW SHOWERS ACROSS THE CENTRAL RIDGE AND VALLEY REGION.
HIGH TEMPS THURSDAY WILL RANGE FROM THE MID-UPPER 30S ACROSS THE
NRN AND WRN MTNS TO THE UPPER 40S IN THE SE.
&&
.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
A SPLIT FLOW PATTERN IS FCST OVER THE LOWER 48 THRU THE MEDIUM
RANGE PERIOD...WITH RATHER MILD TEMPERATURES FOR EARLY DECEMBER
ANTICIPATED AS A PACIFIC AIRMASS MIGRATES FROM WEST TO EAST.
RIDGING AT THE SURFACE AND ALOFT WILL DOMINATE THE REGIONAL
WEATHER PATTERN WITH HIGH CONFIDENCE IN DRY WEATHER THROUGH
MONDAY.
THE KEY FEATURE HEADING INTO THE MIDDLE OF NEXT WEEK WILL BE A
MID LEVEL SYSTEM EVOLVING EASTWARD FROM THE ROCKIES AND POSSIBLY
CUTTING OFF SOMEWHERE BETWEEN TEXAS AND THE OHIO VALLEY. GIVEN THE
LARGE SPREAD AND MEDIUM RANGE MODEL `LIMBO` WILL STAY CLOSE TO
CONTINUITY AND SHOW A MODEST INCREASE IN POPS TOWARD CLIMO BY DAY
7-8. THAT SAID...THE PATTERN MAY VERY WELL REMAIN A DRY ONE
THROUGH THE ENTIRE PERIOD. CONFIDENCE IS LOW REGARDING PCPN RISK
AROUND THE MIDDLE PART OF NEXT WEEK.
&&
.AVIATION /06Z THURSDAY THROUGH MONDAY/...
ANOTHER ROUND OF SHOWERS MOVING THROUGH CENTRAL PA...WHICH SHOULD
BRING MVFR TO IFR CIGS TO THE NORTHERN TERMINALS OVER THE NEXT FEW
HOURS. HOWEVER EXPECT TO SEE SOME DEGRADING CONDITIONS OCCUR
OVERNIGHT...ESPECIALLY IN THE NW AS POST FRONTAL NORTHWESTERLY
FLOW BRINGS UPSLOPE SHOWERS TO THE NW MTNS. OVER THE NEXT FEW
HOURS THE SCT RAIN SHOWERS WILL CHANGE TO SNOW SHOWERS AND
CONTINUE AS SNOW INTO EARLY THURSDAY MORNING ACROSS THE WESTERN
AIRSPACE WITH IFR VIS LKLY TO IMPACT BFD AND JST. WINDS FROM 270
TO 310 DEGREES WILL CONTINUE TO PICK UP WITH GUSTS IN THE 20-25KT
RANGE BY 15Z.
OUTLOOK...
THU...IFR WRN TAFS BCMG MVFR. MVFR TO LOW VFR CIGS CENTRAL AND
EAST WITH LOW CHC FOR -SHSN. 20-25KT SFC WND GUSTS FROM 280-310.
FRI-MON...NO SIG WX EXPECTED.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...DANGELO/LA CORTE
NEAR TERM...DANGELO/LA CORTE
SHORT TERM...LAMBERT
LONG TERM...STEINBUGL
AVIATION...LAMBERT/CERU
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
1149 PM EST WED DEC 2 2015
.SYNOPSIS...
AN UPPER LOW OVER THE SOUTHERN GREAT LAKES WILL MOVE THROUGH THE
REGION OVERNIGHT AND LIFT OUT TO OUR NORTHEAST THURSDAY. A RIDGE
OF HIGH PRESSURE WILL BUILD ACROSS THE EASTERN CONUS FOR THE
WEEKEND WITH FAIR AND MILDER WEATHER.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
A SURFACE TROUGH/SECONDARY COLD FRONT EXTENDS FROM THE LOW NEAR
ALBANY NY BACK THROUGH NRN PA INTO MICHIGAN JUST NORTH OF DETROIT.
THE CORE OF THE COLD AIR ASSOCIATED WITH THE UPPER LOW EXTENDS
FROM WESTERN OHIO INTO IN/IL. THIS WILL TRANSLATE EAST OVERNIGHT
AS THE DEEP UPPER LOW MOVES QUICKLY TOWARD WESTERN PA AND NY.
RADAR SHOWS A SMALL BUT SLOWLY EVOLVING AREA OF RAIN SHOWERS FROM
NW PA DOWN INTO WESTERN CLEARFIELD COUNTY. IT APPEARS TO BE
ASSOCIATED WITH AN AREA OF MID LEVEL DEFORMATION/FRONTOGENETIC
FORCING THAT THE HRRR AND RAP SHOW CONTINUING TO DEVELOP AS IT
PIVOTS THROUGH MAINLY MY NWRN ZONES THROUGHOUT THE
OVERNIGHT...WITH THE BEST ORGANIZATION INDICATED AFTER MIDNIGHT
THROUGH ABOUT SUNRISE.
AS COLDER AIR ARRIVES LATER THIS EVENING AND INTO THE WEE HOURS
OF THURSDAY...THE LIGHT RAIN SHOWERS WILL TURN TO SNOW SHOWERS
OVER THE WEST BEFORE SPREADING EAST INTO THE CENTRAL MOUNTAINS.
A BLEND OF MODEL QPFS YIELDS SNOWFALLS IN THE 1-3 INCH RANGE
WHICH MAY BE TOO HIGH GIVEN THAT A CHANGEOVER TO SNOW WAS
EXPECTED TO HAVE OCCURRED BY NOW. WE DIDN`T CHANGE THE FORECAST
MUCH AND STUCK WITH WITH 1-2 INCHES ACROSS THE NW MTNS AND LAUREL
HIGHLANDS...WITH A COATING TO 1/2 INCH POSSIBLE EVEN ACROSS THE
CENTRAL RIDGE AND VALLEY REGION AFTER 06Z. WE DID BACK OFF THE
ADMITTEDLY SMALL AMOUNTS WE HAD FOR THE LOWER SUSQ AS LATEST
GUIDANCE IS STINGY WITH THE QPF ONCE THE SYSTEM EMERGES EAST OF
THE CENTRAL MOUNTAINS.
LOW TEMPS WILL BE 30 ACROSS THE HIGH TERRAIN OF THE NORTH AND
WEST TO NEAR 40F IN THE LOWER SUSQ VALLEY.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH 6 PM THURSDAY/...
THE UPPER TROUGH AXIS WILL SLIDE ACROSS THE REGION DURING THE
MORNING AND MIDDAY HOURS THURSDAY...ACCOMPANIED BY PLENTY OF
CLOUDS ACROSS THE CENTRAL AND NW MTNS...WHILE PERIODS OF SUNSHINE
WILL DEVELOP ACROSS THE FAVORED DOWNSLOPE REGION OF THE SUSQ
VALLEY AND SCENT PENN.
SNOW SHOWER COVERAGE WILL GRADUALLY DECREASE DURING THE
AFTERNOON AND BECOME CONFINED TO THE MOST FAVORED UPSLOPE AREAS
OF THE LAURELS AND NW MOUNTAINS IN THE WAKE OF THE DEPARTING LOW.
ADDITIONAL SNOW ACCUMS THURSDAY WILL BE LESS THAN ONE INCH IN MOST
PLACES ACROSS NW PA AND THE LAURELS...WITH JUST FLURRIES AND
BRIEF SNOW SHOWERS ACROSS THE CENTRAL RIDGE AND VALLEY REGION.
HIGH TEMPS THURSDAY WILL RANGE FROM THE MID-UPPER 30S ACROSS THE
NRN AND WRN MTNS TO THE UPPER 40S IN THE SE.
&&
.LONG TERM /THURSDAY NIGHT THROUGH WEDNESDAY/...
A SPLIT FLOW PATTERN IS FCST OVER THE LOWER 48 THRU THE MEDIUM
RANGE PERIOD...WITH RATHER MILD TEMPERATURES FOR EARLY DECEMBER
ANTICIPATED AS A PACIFIC AIRMASS MIGRATES FROM WEST TO EAST.
RIDGING AT THE SURFACE AND ALOFT WILL DOMINATE THE REGIONAL
WEATHER PATTERN WITH HIGH CONFIDENCE IN DRY WEATHER THROUGH
MONDAY.
THE KEY FEATURE HEADING INTO THE MIDDLE OF NEXT WEEK WILL BE A
MID LEVEL SYSTEM EVOLVING EASTWARD FROM THE ROCKIES AND POSSIBLY
CUTTING OFF SOMEWHERE BETWEEN TEXAS AND THE OHIO VALLEY. GIVEN THE
LARGE SPREAD AND MEDIUM RANGE MODEL `LIMBO` WILL STAY CLOSE TO
CONTINUITY AND SHOW A MODEST INCREASE IN POPS TOWARD CLIMO BY DAY
7-8. THAT SAID...THE PATTERN MAY VERY WELL REMAIN A DRY ONE
THROUGH THE ENTIRE PERIOD. CONFIDENCE IS LOW REGARDING PCPN RISK
AROUND THE MIDDLE PART OF NEXT WEEK.
&&
.AVIATION /03Z THURSDAY THROUGH MONDAY/...
ANOTHER ROUND OF SHOWERS MOVING THROUGH CENTRAL PA...WHICH SHOULD
BRING MVFR TO IFR CIGS TO THE NORTHERN TERMINALS OVER THE NEXT FEW
HOURS. HOWEVER EXPECT TO SEE SOME DEGRADING CONDITIONS OCCUR
OVERNIGHT...ESPECIALLY IN THE NW AS POST FRONTAL NORTHWESTERLY
FLOW BRINGS UPSLOPE SHOWERS TO THE NW MTNS. OVER THE NEXT FEW
HOURS THE SCT RAIN SHOWERS WILL CHANGE TO SNOW SHOWERS AND
CONTINUE AS SNOW INTO EARLY THURSDAY MORNING ACROSS THE WESTERN
AIRSPACE WITH IFR VIS LKLY TO IMPACT BFD AND JST. WINDS FROM 270
TO 310 DEGREES WILL CONTINUE TO PICK UP WITH GUSTS IN THE 20-25KT
RANGE BY 15Z.
OUTLOOK...
THU...IFR WRN TAFS BCMG MVFR. MVFR TO LOW VFR CIGS CENTRAL AND
EAST WITH LOW CHC FOR -SHSN. 20-25KT SFC WND GUSTS FROM 280-310.
FRI-MON...NO SIG WX EXPECTED.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...LA CORTE
NEAR TERM...LA CORTE
SHORT TERM...LAMBERT
LONG TERM...STEINBUGL
AVIATION...LAMBERT/CERU
FOR FREQUENTLY ASKED QUESTIONS ABOUT THE AREA FORECAST DISCUSSION
VISIT...
HTTP://WEATHER.GOV/SALTLAKECITY/GENERAL/AFD_FAQS.PHP (ALL LOWER CASE)
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
1153 PM EST WED DEC 2 2015
.SYNOPSIS...
A COLD FRONT PASSES OFFSHORE TONIGHT. HIGH PRESSURE FOLLOWS THE
FRONT RESULTING IN DRIER WEATHER AND MORE IN THE WAY OF SEASONAL
TEMPERATURES INTO THE WEEKEND.
&&
.NEAR TERM /THROUGH THURSDAY/...
AS OF 945 PM EST WEDNESDAY...
NOT SEEING ANY RETURNS ON RADAR IN OUR CWA...BUT SOME LIGHT ECHOES
ARE SHOWING UP ON RLX RADARS. THE HIGHER RES MODELS SHOW LITTLE
MAKING IT SOUTH OF BLF OVERNIGHT...BUT SYNOPTIC MODELS ARE USUALLY
MORE ROBUST IN NW FLOW EVENTS. GIVEN THE STRONG CAA MOVING INTO
THE MOUNTAINS PLUS THE UPPER VORT WORKING ACROSS THE LOWER OHIO
VALLEY THIS EVENING...THINK A PERIOD OF RAIN CHANGING TO SNOW
SHOWERS WILL BE IN THE CARDS FOR SE WV...SOUTHWEST TOWARD THE
NC/TN BORDER...THOUGH ONCE YOU GET SOUTH OF BLF-JFZ...THE MOISTURE
LAGS AND THE SUPPORT ALOFT IS LESS. EVEN WITH THIS...SNOWFALL
WOULD BE PUSHING NO MORE THAN ONE INCH AT BEST IN HIGHER
ELEVATIONS OF GREENBRIER...WITH LESS THAN A HALF INCH ELSEWHERE.
THE REST OF THE NIGHT...THE SKIES STAY MOSTLY CLOUDY TO OVERCAST.
CONCERN SEEN ON THE 18Z GFS AND THE LATEST 00Z NAM IS FOR WINDS TO
PICK UP GIVEN 6 HR PRESSURE RISES OF 6-7 MB. LIMITING FACTORS WILL
BE CLOUDS WHICH TEND TO HOLD THE MIXING OF THE HIGHER SPEEDS
DOWN...AND THE LOW LVL JET IS NO MORE THAN 40KTS. THEREFORE...WIND
GUSTS SHOULD BE NO MORE THAN 40-45 MPH ON THE HIGHER RIDGES LEE OF
THE SNOW SHOWERS...NAMELY ALONG THE BLUE RIDGE FROM BOONE TO PEAKS
OF OTTER AND ADJACENT AREAS.
HAVE INCREASED THE WIND GUSTS AND MENTIONED IN THE HWO FURTHER
NORTH ALONG THE BLUE RIDGE AND ALLEGHANY HIGHLANDS ABOUT GUSTS TO
40-45 MPH...WHICH IS UNDER ADVISORY LEVEL WINDS.
AS FOR TEMPS WILL SEE LOWS IN THE UPPER 20S/LOWER 30S HIGHER
RIDGES TO MID 30S TO AROUND 40 EAST. JUST A FEW SPRINKLES/LIGHT
SHOWERS LINGERING OVER SOUTHSIDE VA INTO NW NC PIEDMONT EARLY THIS
EVENING. COLD FRONT SITUATED FROM ERN NY SOUTHWEST TO THE NC
FOOTHILLS. MODELS SHIFT THIS FRONT TO THE COAST BY EARLY
OVERNIGHT. SOME CLEARING TO TAKE PLACE LEE OF THE APPALACHIANS BY
MID/HIGH CLOUDS ASSOCIATED WITH STRONG UPPER JET WILL LINGER INTO
OVERNIGHT...SO SKIES SHOULD STAY MOSTLY CLOUDY TO OVERCAST. WILL
SEE UPSLOPE CLOUDINESS START TO MOVE INTO THE SE WV MTNS AS WE
HEAD THROUGH THE EVENING...BUT MAIN LIFT ASSOCIATED WITH SHORTWAVE
WILL NOT INDUCE RAIN/SNOW SHOWERS 11PM TO MIDNIGHT. MOISTURE
COLUMN IS SHALLOW BUT THE COLD AIR ADVECTION AND STRONG SHORTWAVE
MAY BRING A DUSTING TO QUINWOOD WV BY MORNING.
TEMPS ARE RUNNING MILDER IN THE EAST...AND LIKED THE 21Z HRRR AND
LAMP DEPICTION OF TEMPS THROUGH THIS EVENING...SO BUMPED THEM UP
OUT EAST DELAYING THE COOLER AIR TIL AFTER MIDNIGHT WHEN THE FRONT
MOVES EAST.
AS FOR HYDRO...STILL NOT EXPECTING ANY FLOODING. THE ROANOKE RIVER
IS CRESTING AT MOST LOCATIONS INCLUDING RANDOLPH ALTHOUGH A
SECONDARY RISE IS NOTED UPSTREAM AT ALTAVISTA AND BROOKNEAL...SO
ANOTHER BUMP UP IN THE RIVER AT RANDOLPH IS LIKELY...BUT STILL
EXPECTING IT TO STAY UNDER THE 21 FOOT FLOOD STAGE. MOST RIVERS
ARE FALLING...ALTHOUGH SOME RISES ALONG THE DAN AND MIDDLE JAMES
MAY OCCUR THROUGH THURSDAY MORNING.
PREVIOUS VALID DISCUSSION...
BLUSTERY CONDITIONS CONTINUE ON THURSDAY WITH SOME LINGERING
MORNING SNOW SHOWERS AND SNOW FLURRIES ALONG THE FAR WESTERN
SLOPES OF THE APPALACHIANS. HIGH TEMPERATURES THURSDAY WILL RANGE
FROM THE LOWER 30S IN THE NORTHWEST MOUNTAINS TO AROUND 50 DEGREES
IN THE PIEDMONT.
&&
.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY/...
AS OF 330 PM EST WEDNESDAY...
HIGH PRESSURE OVER CENTRAL APPALACHIANS THURSDAY NIGHT THROUGH
SATURDAY IS EXPECTED TO KEEP CONDITIONS CLEAR. NIGHTLY TEMPERATURES
WERE LOWERED SLIGHTLY BECAUSE OF GUIDANCE CONSENSUS...LIGHT WINDS...
AND VERY LITTLE CLOUD COVER...WHILE AFTERNOON HIGHS WERE KEPT
RELATIVELY THE SAME WITH A FEW LOCATIONS BUMPED UP SLIGHTLY.
EXPECTING A LARGE SPREAD BETWEEN MINIMUM AND MAXIMUM TEMPERATURE DUE
TO VERY DRY AIR MASS.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
AS OF 325 PM EST WEDNESDAY...
POOR MODEL CONSENSUS MONDAY THROUGH WEDNESDAY SHOWS THE ECMWF MOVING
A LOW PRESSURE SYSTEM UP THE SOUTHEAST ATLANTIC COAST NEARLY A DAY
BEFORE THE GFS. A LATER ONSET OF THIS SYSTEM THAN THE ECMWF WAS
FAVORED ALONG WITH THE WPC TIMING WITH A CHANCE FOR PRECIP MOVING
INTO THE REGION ON MONDAY...LINGERING UNTIL WEDNESDAY. MAXIMUM DAILY
TEMPERATURES WERE LOWERED A FEW DEGREES ACROSS THE FORECAST AREA FOR
TUESDAY AND WEDNESDAY...NOTING MORE CLOUD COVER ACROSS THE REGION.
EASTERN TROUGHING CAUSED US TO RAISE POPS BETWEEN TUESDAY INTO
WEDNESDAY DUE TO AN INFLUX OF MOISTURE FROM THE ATLANTIC.
&&
.AVIATION /06Z THURSDAY THROUGH MONDAY/...
AS OF 1140 PM EST WEDNESDAY...
MVFR CIGS WILL IMPACT BLF/LWB THROUGH THE MORNING WITH -SHSN
POSSIBLE. 3KFT CIGS MAY REACH BCB...BUT MAINLY THINKING 4-6KFT
CIGS EAST.
NW WINDS WILL BE THE BIGGER CONCERNS THIS MORNING AS THEY COULD
GUST UP TO 30-35KTS.
AS THE DAY COMMENCES THURSDAY...WINDS WILL PICK UP AT LYH/DAN
WITH GUSTS TO 20KTS.
OVERALL...EXPECT CONTINUED MVFR CIGS AT BLF/LWB THROUGH
THURSDAY...THOUGH THINK CIGS SCATTER OUT DURING THE AFTERNOON.
MEDIUM TO HIGH MEDIUM CONFIDENCE IN CEILINGS...VISIBILITIES AND
WINDS DURING THE PERIOD.
.EXTENDED AVIATION DISCUSSION...
HIGH PRESSURE AND VFR CONDITIONS SHOULD DOMINATE THURSDAY NIGHT
THROUGH THE WEEKEND. PATCHY EARLY MORNING VALLEY FOG MAY PRODUCE
SOME BRIEF IFR CONDITIONS FRI AND SAT MORNING DUE TO MOIST GROUND
CONDITIONS FROM RECENT RAINFALL...AT LWB/BCB ESPECIALLY.
BY MONDAY...THE HIGH EXITS THE MID ATLANTIC COAST WITH A SFC LOW
DEVELOPING OFF THE SOUTHEAST COAST THANKS TO UPPER LOW MOVING
ACROSS KY/TN. THIS MAY BRING SOME MVFR CIGS BACK TO THE FORECAST
AREA...AND MAYBE SOME SHOWERS.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...KK
NEAR TERM...KK/WP
SHORT TERM...AMS
LONG TERM...AMS
AVIATION...KK/WP
AREA FORECAST DISCUSSION...CORRECTED
NWS SEATTLE WA
311 AM PST THU DEC 3 2015
CORRECTIONS TO THE HYDROLOGY SECTION
.SYNOPSIS...A VIGOROUS DEVELOPING FRONTAL SYSTEM WILL REACH THE
COAST TODAY AND MOVE ACROSS WESTERN WASHINGTON THIS EVENING...
FOR RAINY AND VERY WINDY WEATHER. SHOWERY WEATHER WILL FOLLOW THE
FRONT FRIDAY. ANOTHER FRONT WILL BRING MORE RAIN...HEAVY AT
TIMES...SATURDAY AND SATURDAY NIGHT. WET WEATHER WILL CONTINUE
SUNDAY THROUGH WEDNESDAY AS MORE FRONTAL SYSTEMS CROSS THE AREA.
&&
.SHORT TERM...SOUTHWEST FLOW ALOFT CONTINUES OVER WESTERN
WASHINGTON EARLY THIS MORNING...BETWEEN THE UPPER RIDGE DOWNSTREAM
ALONG THE ROCKY MOUNTAINS AND THE DEEP UPPER TROUGH OFFSHORE ALONG
140W. A PACIFIC FRONTAL SYSTEM IS DEVELOPING IN THE SOUTHEAST
QUADRANT OF THE TROUGH...WITH A 993 MB LOW ABOUT 200 NM WEST OF
THE COAST AT THE OREGON/CALIFORNIA BORDER.
IN THE MEANTIME A WARM FRONT AHEAD OF THAT SYSTEM MOVED NORTH
ACROSS WESTERN WASHINGTON OVERNIGHT...BRINGING WIDESPREAD
PRECIPITATION TO THE FORECAST AREA. THE SNOW LEVEL CLIMBED TO 6000
TO 7000 FT...HOWEVER EASTERLY FLOW IS HOLDING THE TEMPERATURE IN
THE CASCADES PASSES AT OR A LITTLE BELOW FREEZING. AT 1 AM THE
WASHINGTON DOT PASS REPORT SHOWED SNOQUALMIE PASS AND STEVENS PASS
AT 26 AND 24 DEGREES...SO SOME OF THE PRECIPITATION THERE IS
PROBABLY FREEZING RAIN. UP TO 2 INCHES OF RAIN HAS FALLEN IN THE
OLYMPIC MOUNTAINS OVERNIGHT...WITH MAINLY A QUARTER TO THREE
QUARTERS OF AN INCH AT THE COAST...AND UP TO A HALF INCH IN THE
INTERIOR LOWLANDS AND THE CASCADES. TEMPERATURES AT 2 AM RANGED
FROM THE LOWER 40S TO THE MID 50S...WITH LOCALLY GUSTY WINDS
ESPECIALLY NEAR THE WEST SLOPES OF THE CASCADES IN THE EAST PUGET
SOUND LOWLANDS.
THE DEVELOPING SYSTEM OFFSHORE WILL MOVE TO THE COAST THIS
AFTERNOON AND INLAND THIS EVENING...AND IT WILL CONTINUE TO BRING
WIDESPREAD PRECIPITATION TO THE AREA WITH LOCAL FREEZING RAIN IN
THE PASSES. A WINTER WEATHER ADVISORY WILL REMAIN IN EFFECT FOR
THE CASCADES THROUGH THIS EVENING.
THE SURFACE LOW IS FORECAST TO DEEPEN TO AROUND 983 MB AS IT
MAKES LANDFALL -- PROBABLY ALONG THE CENTRAL WASHINGTON COAST --
LATE THIS AFTERNOON...THEN CONTINUE NORTHEAST ACROSS THE NORTHWEST
ACROSS THE FORECAST AREA AND INTO SOUTHWEST BRITISH COLUMBIA LATE
THIS EVENING. A HIGH WIND WARNING IS IN EFFECT FOR MOST OF THE
WESTERN WASHINGTON LOWLANDS IN OUR FORECAST AREA FOR THIS
AFTERNOON AND EVENING. CONFIDENCE IS NOT ESPECIALLY HIGH THOUGH...
BECAUSE MODEL SOLUTIONS HAVE BEEN QUITE INCONSISTENT. THE 06Z
SOLUTIONS OF THE NAM AND GFS TAKE THE LOW ON A TRACK FURTHER
WEST...AND IF THEY ARE RIGHT THEN HIGH WINDS WOULD BE UNLIKELY
OVER THE INTERIOR. THE HRRR SOLUTIONS...ON THE OTHER HAND...
CONTINUE TO LOOK SIMILAR TO THE 00Z SUITE OF MODELS UPON WHICH THE
HIGH WIND WARNING IS BASED.
A WEAK UPPER TROUGH WILL BRING MORE SHOWERY WEATHER LATER TONIGHT
AND FRIDAY AS IT MOVES WEST ACROSS THE REGION. THE SNOW LEVEL WILL
FALL TO AROUND 3500 FT BY FRIDAY MORNING...WITH MAINLY 1 TO 6
INCHES OF NEW SNOW ABOVE THAT LEVEL.
ANOTHER FRONTAL BAND WILL PROBABLY REACH THE COAST AND OLYMPIC
PENINSULA LATE FRIDAY NIGHT...AND MOVE SLOWLY ACROSS WESTERN
WASHINGTON SATURDAY AND SATURDAY NIGHT. IT WILL BRING CONSIDERABLE
PRECIPITATION AND LOCALLY WINDY CONDITIONS. WE CAN EXPECT STORM
TOTAL PRECIPITATION OF 1 TO 3.5 INCHES AT THE COAST...2 TO 6
INCHES IN THE OLYMPICS...0.5 TO 2 INCHES IN THE INTERIOR
LOWLANDS...AND MAINLY 1 TO 5 INCHES IN THE CASCADES. THE SNOW
LEVEL WILL BE AROUND 3000 FT AS THE SYSTEM ARRIVES BUT RISE TO
5000 TO 6000 FT AS IT MOVES THROUGH LATE SATURDAY AND SATURDAY
NIGHT. AS MENTIONED IN THE HYDROLOGY SECTION BELOW...THE RAINFALL
OVER THE OLYMPICS COULD BE SUFFICIENT TO DRIVE THE SKOKOMISH RIVER
ABOVE FLOOD STAGE. MCDONNAL
.LONG TERM...ALL THE MODELS SHOW A PROGRESSIVE PATTERN CONTINUING
WITH FAIRLY VIGOROUS FRONTAL SYSTEMS MOVING THROUGH WESTERN
WASHINGTON DURING THE EXTENDED PERIOD. THE FIRST ONE WILL PROBABLY
MOVE THROUGH AROUND SUNDAY OR SUNDAY NIGHT...WITH ANOTHER ONE OR
TWO SYSTEMS MOVING THROUGH BETWEEN MONDAY AND WEDNESDAY. THERE IS
LITTLE AGREEMENT WITH REGARD TO ANY FORECAST DETAILS...AND RUN TO
RUN CONSISTENCY IS RATHER POOR AS WELL. A BROAD BRUSH WET FORECAST
IS RIGHT FOR NOW. THERE IS A GOOD CHANCE THE SNOW LEVEL WILL BE
MAINLY 4500 FT OR HIGHER...POSSIBLY FALLING TO 3000 TO 4000 FT
WEDNESDAY OR WEDNESDAY NIGHT. IT COULD BE LOCALLY WINDY AT TIMES
AS WELL. MCDONNAL
&&
.AVIATION...SATELLITE IMAGERY SHOWS A DEVELOPING 994 LOW ABOUT
250 NM W OF THE SOUTH OREGON COAST THAT IS EXPECTED TO DEEPEN TO
AROUND 984 MB AS IT MOVES ONTO THE CENTRAL WASHINGTON COAST LATE
THIS AFTERNOON AND INTO SW BC THIS EVENING. SW FLOW ALOFT WILL
BECOME STRONG SLY ALOFT THIS AFTERNOON. MOISTURE WILL INCREASE AND
CONDITIONS DETERIORATE IN LOWERING CIGS AND DECREASING VIS IN RA AS
THE LOW APPROACHES TODAY. INCREASING SLY FLOW AT FL020 WILL
CONTRIBUTE TO AREAS OF STRONG LLWS AFTER 20Z AND UNTIL THE LOW MOVES
NORTH OF THE AREA. STRONG SFC AND LOW LEVEL S TO SW WINDS WILL
FOLLOW THE LOW LATE THIS AFTERNOON INTO THIS EVENING. THERE WILL BE
ISOLATED TSTMS OVER THE COASTAL WATERS AND POSSIBLY ONTO THE
WASHINGTON COAST THROUGH THIS EVENING. ALBRECHT
KSEA...DESPITE RA AT TIMES...EXPECT CIGS TO REMAIN 030-050 THROUGH
EARLY THIS AFTERNOON. CIGS WILL LOWER TO BKN020 OVC040 IN SHRA AS
THE LOW MOVES BY TO THE NORTH. WINDS WILL BE E 10-12 KT TODAY WITH
GUSTS TO 25 KT IN THE AFTERNOON. FROM 21Z-01Z EXPECT SLY WIND AT
FL020 TO INCREASE TO 55-60 KT GIVING STG LLWS. SFC WIND WILL
INCREASE TO S 30KTG45 KT AS THE LOW PASSES BY TO THE NORTH 02Z-04Z
THEN SLOWLY SUBSIDE LATE IN THE EVENING. ALBRECHT
&&
.MARINE...SATELLITE IMAGERY SHOWS A DEVELOPING 994 MB LOW ABOUT
250NM W OF THE S OREGON COAST EARLY THIS MORNING. THIS LOW WILL
DEEPEN TO AROUND 984 MB AS IT MOVES ONSHORE AROUND THE GRAYS HARBOR
BAR LATE IN THE AFTERNOON. THE LOW WILL THEN MOVE INTO SW BC DURING
THE EVENING HOURS. WE NOW HAVE GALE WARNINGS FOR ALL WATERS...WITH
STORM WARNINGS FOR THE CENTRAL AND EAST ENTRANCE TO THE STRAIT LATE
THIS AFTN AND EVENING AS FLOW TURNS FROM SE TO W THERE.
WINDS WILL DIMINISH LATE TONIGHT INTO FRI MORNING BETWEEN SYSTEMS.
THEN ANOTHER ROUND OF GALES CAN BE EXPECTED OVER THE COASTAL WATERS
AND PORTIONS OF THE INLAND WATERS FRI NIGHT INTO SAT AS ANOTHER
STRONG FRONT MOVES THROUGH THE AREA.
YET ANOTHER STRONG FRONT WILL MOVE THROUGH THE WATERS SUN NIGHT.
A LONG FETCH OF STG WINDS OFFSHORE WILL CONTRIBUTE TO SEAS REACHING
TO 20-25 FT AT TIMES IN THE COASTAL WATERS SAT AND AGAIN SUN NIGHT.
ALBRECHT
&&
.HYDROLOGY...RIVER FLOODING IS UNLIKELY THROUGH FRIDAY. THE FORECAST
RAINFALL SATURDAY AFTERNOON AND NIGHT COULD BE ENOUGH TO CAUSE THE
SKOKOMISH RIVER TO EXPERIENCE MINOR FLOODING ON SUNDAY...AND WE
COULD ISSUE A FLOOD WATCH FOR THAT LATER TODAY. LONG RANGE MODELS DO
NOT AGREE WELL ON DETAILS FOR SUNDAY THROUGH MONDAY...BUT THEY ALL
KEEP THE PATTERN QUITE WET BUT PROGRESSIVE. NO PARTICULAR SYSTEM
KEEPS HEAVY RAIN OVER WESTERN WASHINGTON FOR VERY LONG...BUT THE
ACCUMULATION OF RAINFALL OVER A SEVERAL DAY PERIOD -- ON TOP OF THE
WET WEATHER BETWEEN TODAY AND SATURDAY -- COULD RESULT IN AT LEAST
SOME MINOR FLOODING NEXT WEEK. BURKE/MCDONNAL
&&
.SEW WATCHES/WARNINGS/ADVISORIES...
WA...HIGH WIND WARNING FROM 2 PM THIS AFTERNOON TO 10 PM PST THIS
EVENING FOR ADMIRALTY INLET AREA-BELLEVUE AND VICINITY-
BREMERTON AND VICINITY-EAST PUGET SOUND LOWLANDS-EVERETT
AND VICINITY-HOOD CANAL AREA-SAN JUAN COUNTY-SEATTLE AND
VICINITY-SOUTHWEST INTERIOR-TACOMA AREA-WESTERN SKAGIT
COUNTY-WESTERN WHATCOM COUNTY.
WINTER WEATHER ADVISORY UNTIL 10 PM PST THIS EVENING FOR
CASCADES OF PIERCE AND LEWIS COUNTIES-CASCADES OF SNOHOMISH
AND KING COUNTIES-CASCADES OF WHATCOM AND SKAGIT COUNTIES.
HIGH WIND WARNING FROM 1 PM THIS AFTERNOON TO 9 PM PST THIS
EVENING FOR CENTRAL COAST-NORTH COAST.
WIND ADVISORY FROM 2 PM THIS AFTERNOON TO 10 PM PST THIS EVENING
FOR LOWER CHEHALIS VALLEY AREA.
WIND ADVISORY FROM 2 PM THIS AFTERNOON TO MIDNIGHT PST TONIGHT
FOR EASTERN STRAIT OF JUAN DE FUCA-WESTERN STRAIT OF JUAN
DE FUCA.
PZ...SMALL CRAFT ADVISORY FOR ROUGH BAR UNTIL 3 AM PST FRIDAY FOR
GRAYS HARBOR BAR.
GALE WARNING UNTIL 10 PM PST THIS EVENING FOR ADMIRALTY INLET-
COASTAL WATERS FROM CAPE FLATTERY TO JAMES ISLAND 10 TO 60
NM-COASTAL WATERS FROM CAPE FLATTERY TO JAMES ISLAND OUT 10
NM-COASTAL WATERS FROM JAMES ISLAND TO POINT GRENVILLE 10
TO 60 NM-COASTAL WATERS FROM JAMES ISLAND TO POINT
GRENVILLE OUT 10 NM-COASTAL WATERS FROM POINT GRENVILLE TO
CAPE SHOALWATER 10 TO 60 NM-COASTAL WATERS FROM POINT
GRENVILLE TO CAPE SHOALWATER OUT 10 NM-NORTHERN INLAND
WATERS INCLUDING THE SAN JUAN ISLANDS-WEST ENTRANCE U.S.
WATERS STRAIT OF JUAN DE FUCA.
STORM WARNING FROM 2 PM THIS AFTERNOON TO MIDNIGHT PST TONIGHT
FOR CENTRAL U.S. WATERS STRAIT OF JUAN DE FUCA-EAST
ENTRANCE U.S. WATERS STRAIT OF JUAN DE FUCA.
GALE WARNING UNTIL 2 PM PST THIS AFTERNOON FOR EAST ENTRANCE
U.S. WATERS STRAIT OF JUAN DE FUCA.
GALE WARNING FROM 2 PM THIS AFTERNOON TO MIDNIGHT PST TONIGHT
FOR PUGET SOUND AND HOOD CANAL.
&&
$$
WWW.WEATHER.GOV/SEATTLE
YOU CAN SEE AN ILLUSTRATED VERSION OF THIS DISCUSSION AT
WWW.WEATHER.GOV/SEATTLE/GAFD/LATEST_WEBAFD.HTML
AN ILLUSTRATED VERSION OF THIS FORECAST DISCUSSION CAN BE SEEN AT
WWW.WEATHER.GOV/SEATTLE/GAFD/LATEST_WEBAFD.HTML
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
259 PM CST THU DEC 3 2015
.TONIGHT AND FRIDAY...FORECAST CONFIDENCE...MEDIUM
CLOUDS CONTINUE TO DECREASE FROM THE NORTHWEST AS HIGH PRESSURE
BUILDS INTO THE AREA. CONSENSUS OF MODELS SUGGEST SKIES SHOULD
BECOME MOSTLY CLEAR ACROSS SOUTHERN WISCONSIN THIS EVENING. LATEST
HRRR HANGS ONTO HIGHER LOW LEVEL RH THROUGH MUCH OF THE NIGHT
THOUGH...SO SOMETHING WORTH KEEPING AN EYE ON. LINGERING CLOUDS
WOULD ALSO CERTAINLY IMPACT LOWS TONIGHT.
KEPT MENTION OF PATCHY FOG ACROSS THE WESTERN HALF OF THE FORECAST
AREA LATER TONIGHT INTO FRIDAY MORNING...AS WINDS WILL BE LIGHTER
THERE.
WITH PLENTY OF SUNSHINE EXPECTED...LEANED TOWARD MILDER ECMWF AND
CANADIAN FOR TEMPS FRIDAY...AS GFS AND PARTICULARLY NAM SEEM
UNDERDONE ONCE AGAIN.
.FRIDAY NIGHT AND SATURDAY...FORECAST CONFIDENCE IS HIGH.
SURFACE HIGH PRESSURE WILL DOMINATE FROM THE OHIO VALLEY NORTH
THROUGH THE GREAT LAKES. HOWEVER...THE UPPER RIDGE AXIS WILL SLIDE
EAST OF THE AREA ALLOWING A WEAK SHORT WAVE TROF TO LIFT INTO
WISCONSIN. ALTHOUGH THE COLUMN WILL BE MUCH TOO DRY FOR ANY
PRECIP...THIS FEATURE COULD BRING SOME CLOUDS. 925MB TEMPS WILL
HOVER AROUND 6-7C...BUT GIVEN THE CLOUDS AND LIGHT WINDS...OUR
MIXING POTENTIAL WILL BE LIMITED. THUS WILL KEEP TEMPS IN THE
40S...THOUGH COULD JUST HIT 50 IN THE FAR SOUTHEAST.
.SUNDAY AND SUNDAY NIGHT...FORECAST CONFIDENCE IS HIGH.
A MID LEVEL TROF DRIFTING OUT OF THE PLAINS IS EXPECTED TO CLOSE
OFF BY THE TIME IT REACHES ILLINOIS ON SUNDAY. THE COLUMN REMAINS
VERY DRY AND THE DYNAMICS WEAKEN OVER WISCONSIN AS THE TROF AXIS
REACHES WI SUNDAY MORNING. THE MODELS STILL HINT AT A VERY SMALL
POTENTIAL FOR SHOWERS WEST OF MADISON SUNDAY MORNING...SO WILL
KEEP THEM. SHOULD HAVE MORE CLOUDS ACROSS THE ENTIRE AREA WITH
TEMPS A BIT COOLER THAN SATURDAY...STILL ABOVE NORMAL.
.MONDAY THROUGH THURSDAY...FORECAST CONFIDENCE IS HIGH.
IT STILL LOOKS DRY WHILE WE SIT UNDER MOSTLY A SOUTHWEST UPPER
LEVEL FLOW. AT THE SURFACE WE/LL ON THE WESTERN EDGE OF A LARGE
HIGH PRESSURE SYSTEM COVERING THE EASTERN U.S. HIGH TEMPS WILL
CONTINUE TO RUN IN THE LOWER TO MID 40S /ABOUT 10 DEGREES ABOVE
NORMAL/ WITH A MIX OF CLOUDS AND SUN THROUGH MUCH OF NEXT WEEK.
THE ECMWF AND THE GFS ARE SHOWING THINGS GETTING A BIT UNSETTLED
EITHER THURSDAY OR FRIDAY NEXT WEEK...BUT WITH MILD TEMPS. SO ANY
PRECIP WOULD BE RAIN. RIGHT NOW THERE IS TOO MUCH UNCERTAINTY THIS
FAR OUT...SO WILL KEEP THE DRY LOOK THROUGH THURSDAY.
&&
.AVIATION/00Z TAFS/...
EXPECTING CLEARING TO CONTINUE TO WORK IN FROM THE WEST THIS
AFTERNOON INTO THE EVENING AS HIGH PRESSURE BUILDS INTO THE REGION.
LATEST HRRR HOLDS ONTO CLOUDS FOR MUCH OF THE AREA THROUGH THE
EVENING AND INTO AT LEAST EARLY NIGHT THOUGH...SO SOMETHING TO KEEP
AN EYE ON. IF LOW CLOUDS DO EXIT AS ANTICIPATED...SHOULD SEE ONLY
PASSING HIGH CLOUDS FOR THE OVERNIGHT HOURS. MOSTLY SUNNY SKIES THEN
EXPECTED ON FRIDAY.
COULD SEE SOME PATCHY FOG FORM LATER TONIGHT INTO FRIDAY MORNING AS
THE HIGH BUILDS...WITH MOSTLY CLEAR SKIES AND LIGHTER WINDS IN
PLACE. BEST CHANCE WOULD BE WESTERN HALF OF THE FORECAST AREA WHERE
WINDS WILL BE LIGHTER.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...NONE.
&&
$$
TONIGHT/FRIDAY AND AVIATION/MARINE...DDV
FRIDAY NIGHT THROUGH THURSDAY...DAVIS
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1142 PM CST WED DEC 2 2015
.SHORT TERM...(TONIGHT THROUGH THURSDAY NIGHT)
ISSUED AT 130 PM CST WED DEC 2 2015
CLOUD TRENDS THROUGH TONIGHT AND FOG POTENTIAL THURSDAY NIGHT ARE
THE MAIN CONCERNS IN THE SHORT TERM.
LOOP OF WATER VAPOR SATELLITE IMAGERY AND RAP ANALYSIS SHOW CENTER
OF CLOSED LOW ALONG THE WI/IL BORDER THIS AFTERNOON. LIGHT SNOW
ACTIVITY ASSOCIATED WITH THE LOW HAS SHIFTED EAST OF THE AREA.
MEANWHILE...LINGERING DEFORMATION CLOUD COVER HANGING ACROSS THE
REGION WITH TEMPERATURES IN THE LOWER 30S.
FOR TONIGHT...MODELS AND SYNTHETIC LOW CLOUD/FOG IMAGERY SHOW A SLOW
WEST TO EAST CLEARING OF THE CLOUD COVER //BASICALLY UP TO THE
MISSISSIPPI RIVER BY SUNRISE// AS THE LOW PULLS EAST INTO THE GREAT
LAKES REGION. THIS CLEARING WILL PROVIDE FOR SEASONALLY CHILLY
OVERNIGHT LOWS WEST OF THE MISSISSIPPI IN THE TEENS...WHILE ALONG
AND EAST OF THE RIVER UNDER MORE CLOUD COVER TEMPERATURES
ARE EXPECTED SETTLE INTO THE MIDDLE 20S.
HIGH PRESSURE BUILDING INTO THE AREA THURSDAY WILL PRODUCE INCREASED
SUNSHINE WITH HIGHS TOPPING OFF IN THE MIDDLE 30S TO A FEW LOWER
40S. THIS WILL MELT MOST OF THE SNOW THAT FELL THE LAST COUPLE DAY.
THERE IS SOME CONCERN WHAT IMPACT ALL THAT MELTED SNOW WILL HAVE ON
FOG/STRATUS POTENTIAL LATE THURSDAY NIGHT. WHILE NAM/GFS SOUNDINGS
ARE DRY...SREF SHOWS HIGH PROBABILITY OF LOW CLOUD/FOG GIVEN THE
DAMP LOWER BOUNDARY LAYER AND RIDGE OF HIGH PRESSURE OVERHEAD. FOR
NOW...HAVE ADDED PATCHY FOG MENTION AND WILL HAVE TO WAIT TO SEE
WHAT TOMORROW BRINGS AS FAR AS DEW POINT RESPONSE TO THE SNOW MELT.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 130 PM CST WED DEC 2 2015
FOG POTENTIAL FRIDAY MORNING AND PRECIPITATION CHANCE SATURDAY NIGHT
ARE THE MAIN LONG TERM CONCERNS.
WILL HAVE TO WATCH FRIDAY MORNING AS THERE COULD BE SOME LINGERING
FOG POTENTIAL...BUT AS THE RIDGE AXIS SHIFTS EAST AND SOUTHWEST
WINDS KICK IN FOR MIXING...SUNSHINE SHOULD BE AMPLE THROUGH THE REST
OF THE DAY. GFS/NAM SHOWING 925MB TEMPERATURES INCREASING TO 6-8C BY
AFTERNOON...WHICH SHOULD PRODUCE HIGHS AT THE SURFACE IN THE 40S.
SATURDAY WILL LIKELY SEE AN INCREASE IN CLOUD COVER...ESPECIALLY BY
LATER IN THE AFTERNOON. THIS WILL BE AHEAD OF AN APPROACHING MID-
LEVEL TROUGH/SURFACE COLD FRONT MAKING ITS WAY EAST ACROSS THE
PLANS. OTHERWISE...PLAN ON HIGHS WELL ABOVE NORMAL IN THE
MIDDLE/UPPER 40S.
FOR SATURDAY NIGHT...THE NAM/GFS/ECMWF ALL SHOW A GOOD AMOUNT OF LOW-
LEVEL/0.5KM MOISTURE ADVECTING NORTHEASTWARD INTO THE AREA FOR AN
INCREASE IN STRATUS CLOUD COVER. THE GFS ALSO SHOWING DECENT/DEEP850-
500MB FRONTOGENESIS ALONG/BEHIND THE FRONTAL BOUNDARY FOR ENOUGH
FORCING FOR SOME LIGHT RAIN OR SNOW. ADDED A LIGHT CHANCE MENTION
FOR NOW.
LOOKS QUIET/MILD THROUGH THE REST OF THE PERIOD AS STORM TRACK
REMAINS WELL NORTH INTO CANADA. PLAN ON HIGHS REMAINING NEARLY 10
DEGREES ABOVE NORMAL IN THE UPPER 30S TO THE MIDDLE 40S.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1140 PM CST WED DEC 2 2015
CYCLONIC FLOW ALOFT WILL KEEP A IFR/MVFR DECK OF CLOUDS IN PLACE
THROUGH 03.12Z AT KRST AND 03.16Z AT KLSE. UNLIKE THE EARLIER MODEL
GUIDANCE...THIS SET OF MODELS DO NOT DEVELOP DENSE FOG AFTER THE
CLOUDS CLEARED...SO THERE WAS NO NEED TO ADD IT. EVEN THOUGH THE
DENSE FOG IS NOT SHOWING UP...WILL HAVE TO WATCH FOR THE POTENTIAL
OF SOME MVFR FOG SINCE THERE IS SOME OF THAT ALREADY SHOWING UP
WEST OF INTERSTATE 35.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...DAS
LONG TERM....DAS
AVIATION...BOYNE
AREA FORECAST DISCUSSION
NWS MELBOURNE FL
455 AM EST SAT DEC 5 2015
.DISCUSSION...
...WINDY WITH ROUGH SURF AND HAZARDOUS BOATING CONDITIONS THIS
WEEKEND...
TODAY-TONIGHT...
H30-H20 JET STREAK LIFTING OFF THE SE SEABOARD WILL PULL A DEEP HI
PRES RIDGE ACRS THE ERN CONUS. THE BASE OF THE RIDGE WILL INTERACT
WITH A WEAK FRONTAL TROF OVER S FL AND THE NRN BAHAMAS TO GENERATE A
BRISK NE FLOW ACRS CENTRAL FL. THE USAF 915HZ PROFILER HAS BEEN
MEASURING 25-30KT WINDS THRU THE H100-H85 LYR...BACKING TO THE W/SW
THRU THE H85-H70 LYR. THIS INDICATES INCREASED POTENTIAL FOR
ISENTROPIC LIFT...CONFIRMED BY LATEST RUC ANALYSIS.
FRONTAL MOISTURE BAND HAS PUSHED INTO S FL WITH PWAT VALUES ARND
2.1" AT KMFL/KEYW. MOISTURE PROFILE DECREASES NWD AS AN H85-H50
CYCLONE OVER THE DEEP SOUTH HAS BEGUN TO PUSH DRIER MID LVL AIR INTO
CENTRAL FL. PWATS DECREASE TO ARND 1.5" AT KXMR/KTBW...THEN TO ARND
1.0" AT KJAX. RADAR HAS BEEN DETECTING BANDS OF LIGHT SHRAS PUSHING
ONSHORE FROM SEBASTIAN INLET SWD....BUT NONE ARE MAKING IT INTO THE
INTERIOR.
AS THE JET STREAK LIFTS OUT OF THE AREA...IT WILL KEEP THE S HALF OF
THE PENINSULA UNDER ITS ASCENDING RIGHT REAR QUAD. MEANWHILE...THE
MID LVL ISENTROPIC LIFT AND ENHANCED LOW LVL CONVERGENCE IN THE
VCNTY OF THE FRONT WILL PROVIDE SUFFICIENT DYNAMIC SUPPORT TO KEEP
50/60 POPS IN FOR THE TREASURE COAST AND LAKE OKEECHOBEE AREA. POPS
DECREASING TO 30-40PCT FROM BREVARD/OSCEOLA COUNTY NWD TO REFLECT
THE DECREASING MOISTURE. DRY MID LVL AIR WILL ADVECT ACRS THE CWA
OVERNIGHT AS THE TROF OVER THE DEEP S DRIFTS OFF THE CAROLINA
COAST... POPS DROPPING TO 30PCT TREASURE COAST...AOB 20PCT
ELSEWHERE. PRECIP PRIMARILY WILL BE IN THE FORM OF BRIEF LOW TOPPED
SHRAS. LOW RAINFALL POTENTIAL WITH 24HR QPF BTWN 0.10"-0.25" ALONG
THE TREASURE COAST...AOB 0.10" ELSEWHERE.
NO SIG CHANGE IN AIRMASS WITH THE PERSISTENT NE FLOW...TEMPS NOT
EXPECTED TO DEVIATE MORE THAN A DEG OR TWO FROM FRI. AFTN MAXES IN
THE M/U70S WITH A FEW SPOTS TOUCHING 80F...MIN TEMPS MIN TEMPS
L/M60S INTERIOR AND U60S/L70S ALONG THE COAST. COASTAL COUNTIES NOT
EXPECTED TO SEE TEMPS FLUCTUATE BY MORE THAN 10F.
SUN-TUE...PROGRESSIVE SPLIT FLOW FLOW PATTERN CONTINUES OVER THE
CONUS WITH SHORT WAVE TROUGHS IN THE NORTHERN STREAM REMAINING WELL
NORTH OF FL A WEAKER SRN BRANCH IS BECOMING BETTER ESTABLISHED...
BUT HAS LITTLE IN THE WAY OF DISCRETE DISTURBANCES POISED TO IMPACT
THE STATE.
AN AMPLIFIED TROUGH PUSHES THROUGH THE MS VLY SUN...THE OH VLY MON
AND OFFSHORE THE EASTERN SEABOARD TUE. THIS WILL INDUCE SFC WAVE
DEVELOPMENT OFFSHORE THE CAROLINAS LATE MON...WHICH UNDERGOES FAIRLY
RAPID INTENSIFICATION WELL OFFSHORE THE MID ATLC/NERN CONUS AS IT
MOVES ENE. THE GFS/ECM ARE IN RESPECTABLE AGREEMENT WITH LOCATION/
INTENSITY OF THE LOW AND ITS IMPACTS ON FL. STRONG ONSHORE WINDS
SUNDAY WILL GRADUALLY EASE AND BACK TO NRLY SUN NIGHT-EARLY MON AS
AN INVERTED TROUGH FORMS OFF THE FL EAST COAST. AS THE LOW LIFTS
QUICKLY NEWD...HIGH PRES AND BRIEF SHOT OF COOLER/DRIER AIR WILL
POUR SWD INTO FL FROM LATE MON INTO TUE....BEFORE WINDS VEERING TO
ONSHORE TUE AFTN-EVENING START TO SLOWLY MODIFY THE LOCAL AIR MASS.
BREEZY TO WINDY CONDITIONS START TO EASE MON AND EVEN MORESO TUE.
PRECIP REGIME WILL CONSIST OF FAST-MOVING LOW TOPPED SHOWERS...
MOSTLY LIGHT...WITH RAIN CHCS RETREATING TWD THE COAST/SEAWARD AS
WINDS BACK FOR A TIME. MAX TEMPS IN THE U70S-NEAR 80F SUN WITH
MINS MAINLY IN THE M-U60S...SOME L70S ALONG THE BARRIER ISLANDS.
M-U70S FOR HIGHS MON (SOME L70S COASTAL VOLUSIA). INLAND MINS DROP
INTO THE M-U50S MONDAY NIGHT AS BACKING WINDS WILL SUPPORT STEADY
COOL AIR ADVECTION. HOWEVER BLYR WINDS AVG 360DEG...WHICH IS ABOUT
15-20 DEGREES OF ONSHORE COMPONENT. THIS WILL RESULT IN A SHARP TEMP
GRADIENT FOR MAINLAND VS BARRIER ISLANDS OF THE COASTAL COS.
SLIGHTLY COOLER OVERALL FOR TUE...L-M70S NORTH...M-U70S SOUTH FOR
MAXES. MINS M-U50S INLAND...WITH SOME L50S FAR NORTH...GENERALLY
L-M60S OR THE COAST.
WED-FRI...WEAK HIGH PRES RIDGE AXIS WILL SETTLE ACROSS SRN MS/AL/GA
AND NRNMOST FL WED-WED NIGHT...WHICH WILL KEEP CTRL FL IN A LIGHT
ONSHORE FLOW REGIME WITH GENERALLY DRY CONDITIONS SAVE FOR A SLIGHT
CHANCE OF SHOWERS FOR THE LAKE O/TREASURE COAST REGION. BY THU...AS
WAS THE CASE 24HRS AGO...THE GLOBAL MODELS SHOW VERY DIVERGENT SOLNS
W/R/T A MID LEVEL SHORT WAVE TROUGH IN THE SRN STREAM IMPACTING FL
LATE NEXT WEEK. THE ECM IS MUCH FASTER WITH THIS FEATURE...BRINGING
A FAST-MOVING FLAT/POS TILT FEATURE ACROSS THE STATE THU NIGHT...
WHICH KEEPS MOST IF NOT ALL OF THE PRECIP SOUTH/EAST OF CTRL FL.
AT THE SAME TIME THE ECM HAS THE TROUGH OVER CTRL/SOUTH FL...THE GFS
IS LAGGING THIS FEATURE WELL TO THE WEST (JUST OFFSHORE THE SOUTH TX
COAST) BEFORE SHEARING IT OUT FRI-FRI NIGHT AS IT KICKS ENE-WD OVER
THE GOMEX AND OVER FL BY FRIDAY NIGHT.
HENCE...THE ECM POINTS TO CONT`D DRY WX FOR THU-FRI...WHILE THE GFS
SLOWLY INCREASES RAIN CHCS...ESPECIALLY FRI OVER THE SRN CWA. AS IS
THE CASE WITH FAST/ZONAL FLOW...SPECIFIC MODEL-ADVERTISED DETAILS IN
THE XTD RANGE (DAYS 5-7) WHICH HAVE ALREADY SHOWN CHANGES FROM FRI
AM ARE VERY LIKELY TO CONTINUE HAVING CONTINUITY PROBLEMS. THUS...THE
CURRENT FCST COMMITS TO NEITHER SOLUTION AND PAINTS SMALL RAIN CHCS
FOR BOTH DAYS. TEMPS WILL REMAIN ABOVE AVERAGE THROUGH THE PERIOD.
EARLY DECEMBER NORMAL MAXES FOR ECFL ARE L70S NORTH AND M-U70S SOUTH
WITH MINS IN THE L-M50S,,,EXCEPT U50S ALONG THE MARTIN COUNTY COAST.
&&
.AVIATION...THRU 06/12Z.
SFC WNDS: THRU 05/15Z...N/NE 7-12KTS...OCNL G20KTS CSTL SITES N OF
KVRB. BTWN 05/15Z-06/03Z...E/NE ARND 15-20KTS WITH G22-25KTS. AFT
06/03Z...N/NE 10-13KTS...OCNL G22KTS COASTAL SITES.
VSBY/WX/CIGS: THRU 05/14Z...N OF KISM-KDAB PREVAILING CIGS BTWN
FL006-009...S OF KISM-KMLB PREVAILING CIGS BTWN FL060-080 WITH BRIEF
ISOLD MVFR SHRAS. BTWN 05/14Z-05/24Z...PREVAILING CIGS BTWN
FL040-060...MVFR -SHRAS LIKELY BTWN KVRB-KSUA...CHC MVFR -SHRAS
ELSEWHERE. AFT 06/00Z...PREVAILING CIGS BTWN FL040-060...CHC MVFR
SHRAS BTWN KVRB-KSUA...SLGT CHC MVFR -SHRAS ELSEWHERE.
&&
.MARINE...
TODAY-TONIGHT...HAZARDOUS BOATING CONDITIONS TO CONTINUE. A LARGE
HI PRES RIDGE BLANKETING THE ERN CONUS WILL INTERACT WITH A FRONTAL
TROF OVER S FL TO GENERATE A FRESH TO STRONG NE BREEZE OVER THE
LCL ATLC. DATA BUOYS MEASURING 5-8FT SEAS NEARSHORE AND 9-12FT
OFFSHORE WITH DOMINANT PDS BTWN 8-9SEC. GUSTS NEAR GALE FORCE
EXPECTED OVER THE OFFSHORE WATERS. NO CHANGES TO THE CURRENT SCA.
SUN-MON...STOUT ONSHORE (NE-ENE) WINDS WILL PREVAIL AGAIN SUNDAY
BEFORE RELENTING SUNDAY EVENING/OVERNIGHT AS AN INVERTED TROUGH
DEVELOPS EAST OF FL. LOW SPINNING UP WELL TO THE NE WILL RESULT
IN BRIEF INCREASE IN NRLY WINDS MON/MON NIGHT WHICH COULD BRIEFLY
KICK WINDS BACK UP TO AROUND 20KT. AT THE VERY LEAST...EXPECT
CAUTIONARY CONDITIONS TO CONTINUE ONCE THE SCA EXPIRES.
TUE-WED...WINDS SLACKEN FROM 10-15KT TO AOB 10KT AS THEY VEER FROM
NE TO E. CONSEQUENTLY...SEAS WILL SUBSIDE TO 3-4FT IN A SMALL
LINGERING SWELL.
&&
.PRELIMINARY POINT TEMPS/POPS...
DAB 76 67 76 65 / 40 20 30 30
MCO 80 66 79 65 / 30 20 20 20
MLB 79 73 79 69 / 40 20 30 30
VRB 78 74 79 69 / 50 30 40 40
LEE 78 62 78 61 / 30 10 20 10
SFB 78 65 78 64 / 30 20 20 20
ORL 79 66 79 64 / 30 20 20 20
FPR 79 73 79 70 / 60 30 40 50
&&
.MLB WATCHES/WARNINGS/ADVISORIES...
FL...LAKE WIND ADVISORY FROM 7 AM THIS MORNING TO 7 PM EST THIS
EVENING FOR COASTAL VOLUSIA COUNTY-INDIAN RIVER-MARTIN-
NORTHERN BREVARD COUNTY-SOUTHERN BREVARD COUNTY-ST. LUCIE.
HIGH SURF ADVISORY UNTIL 4 PM EST SUNDAY FOR COASTAL VOLUSIA
COUNTY-INDIAN RIVER-MARTIN-NORTHERN BREVARD COUNTY-SOUTHERN
BREVARD COUNTY-ST. LUCIE.
AM...SMALL CRAFT ADVISORY UNTIL 4 AM EST MONDAY FOR FLAGLER BEACH TO
VOLUSIA-BREVARD COUNTY LINE 0-20 NM-FLAGLER BEACH TO
VOLUSIA-BREVARD COUNTY LINE 20-60 NM-SEBASTIAN INLET TO
JUPITER INLET 0-20 NM-SEBASTIAN INLET TO JUPITER INLET 20-
60 NM-VOLUSIA-BREVARD COUNTY LINE TO SEBASTIAN INLET 0-20
NM-VOLUSIA-BREVARD COUNTY LINE TO SEBASTIAN INLET 20-60 NM.
&&
$$
SHORT TERM/AVIATION...BRAGAW
LONG TERM/IMPACT WX....CRISTALDI
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
315 AM CST SAT DEC 5 2015
.SHORT TERM...
312 AM CST
THROUGH SUNDAY NIGHT...
LOW STRATUS AND FOG THE PRIMARY FORECAST CONCERNS OVER THE NEXT
COUPLE DAYS. SURFACE HIGH PRESSURE IS CENTERED OVER THE UPPER OHIO
VALLEY EARLY THIS MORNING AND IS PROGGED TO BUILD TOWARDS THE
MID ATLANTIC COAST OVER THE WEEKEND. SATELLITE IMAGERY AND SURFACE
OBS SHOWS LOW STRATUS AND FOG BLANKETING THE EASTERN 2/3 OR SO OF
ILLINOIS AND PRACTICALLY ALL OF INDIANA. CLOUDS HAVE BEEN STEADILY
SPREADING NORTHWEST OVERNIGHT AND SHOULD BLANKET THE ENTIRE
FORECAST AREA THROUGH THE MORNING. THEREAFTER...THE ONLY MODEL
THAT WANTS TO HOLD ONTO THE CLOUD COVER THROUGH THE MAJORITY OF
THE DAY IS THE HRRR WHICH SEEMS FAIRLY REASONABLE GIVEN LACK OF
EROSION YESTERDAY. MOST OTHER MODELS BEGIN TO ERODE THE STRATUS BY
MIDDAY HOWEVER A RATHER IMPRESSIVE LOW LEVEL INVERSION COULD KEEP
THE LOW LEVEL MOISTURE TRAPPED THROUGH MUCH OF THE WEEKEND. 05Z
AMDAR SOUNDING OUT OF THE CHICAGO AREA SHOWED 980MB TEMP OF 0.3C
SHARPLY WARMING TO 9.0C AROUND 935MB. LATEST FORECAST GOES UNDER
THE ASSUMPTION THAT MOST OF THE CWA WILL REMAIN UNDER OVERCAST
SKIES AND HAVE ADJUSTED TEMPS DOWN QUITE A BIT FROM PREVIOUS
FORECASTS. FAR NORTH CENTRAL ILLINOIS WILL HAVE THE BEST CHANCE TO
SEE SOME EROSION ALONG THE EDGE OF THE STRATUS DECK BUT CONFIDENCE
IS LOW HOW THIS WILL PLAY OUT OR WHERE TO DRAW THE LINE. AS IS
TYPICAL WITH THESE SCENARIOS THERE IS LARGE BUST POTENTIAL...WITH
HIGHS ONLY IN THE UPPER 30S TO AROUND 40 ON THE COLD END UNDER
CLOUDS ALL DAY BUT IF SUNSHINE IS ABLE TO BREAK THROUGH...THOSE
VERY WARM TEMPS ALOFT WOULD SUPPORT TEMPERATURES QUICKLY SHOOTING
UP WITH HIGHS IN THE LOW 50S. OVERNIGHT...BOUNDARY LAYER FLOW
BACKS SLIGHTLY SO WOULD ANTICIPATE ANY LOW CIGS TO SPREAD BACK TO
ANY AREAS IN NORTH CENTRAL ILLINOIS THAT MIGHT ERODE ALONG THE
EDGE OF THE STRATUS...BUT CONFIDENCE IS FAIRLY LOW HOW THIS WILL
PLAY OUT.
SATURDAY NIGHT INTO SUNDAY...AN UPPER LEVEL WAVE WILL TRANSLATE
EAST ACROSS THE PLAINS REACHING THE OHIO VALLEY BY SUNDAY
EVENING. MID LEVEL HEIGHT FALLS IN ADVANCE OF THIS SYSTEM BEGIN TO
OVERSPREAD NORTHERN ILLINOIS SATURDAY NIGHT THOUGH THE BULK OF THE
FORCING STAYS SOUTH OF THE CWA DURING THE DAY SUNDAY. OUTSIDE OF
THE POSSIBLE CONTINUING LOW STRATUS...FAIRLY LITTLE MOISTURE IS
EXPECTED WITH THIS SYSTEM. MIGHT BE ABLE TO SQUEEZE OUT SOME
DRIZZLE SATURDAY NIGHT INTO EARLY SUNDAY BUT OTHERWISE CONFINED
POPS TO SOUTHWEST AREAS OF THE CWA AND ONLY SLIGHT CHC. LOW LEVEL
CLOUDS IF STILL AROUND EXPECTED TO FINALLY ERODE SUNDAY...HOWEVER
MID AND HIGH CLOUD COVER WILL BE INCREASING ACROSS THE AREA.
DEUBELBEISS
&&
.LONG TERM...
312 AM CST
MONDAY THROUGH FRIDAY...
UPPER PATTERN WILL BECOME ZONAL FOR THE UPCOMING WEEK WITH A
SERIES OF DISTURBANCES BRINGING PERIODIC CHANCES FOR PRECIP
PARTICULARLY THE LATTER HALF OF THE WEEK. TEMPERATURES SHOULD
REMAIN MILD THROUGH THE ENTIRE WEEK WITH A GRADUAL WARMING TREND
EXPECTED. TEMPERATURES ON MONDAY WILL MAX IN THE MID 40S ACROSS
THE FORECAST AREA AND LOW 50S ARE POSSIBLE BY THURSDAY AND FRIDAY.
BOTH THE ECMWF AND GFS ADVERTISE A SHORTWAVE TROUGH DROPPING
ACROSS UPPER MIDWEST/WESTERN GREAT LAKES WEDNESDAY NIGHT.
THEN...WILL HAVE TO KEEP A CLOSE EYE ON A POTENTIALLY MORE POTENT
SYSTEM LATE IN THE WEEK...THOUGH MODELS CONTINUE TO BOUNCE AROUND
ON THE DETAILS AS THEY STRUGGLE TO HANDLE THE PHASING OF UPPER
LEVEL ENERGY.
DEUBELBEISS
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 09Z...
* LIFR CIGS AND IFR/LIFR VSBY WILL PERSIST THROUGH AT LEAST MID
MORNING...POSSIBLY THROUGH MIDDAY.
* STRATUS/FOG MAY CLEAR OUT LATER THIS AFTERNOON.
RATZER
//DISCUSSION...UPDATED 09Z...
AFTER INITIAL DROP AS LOW AS 1/2SM AND OVC002 AT MDW EARLIER...
CONDITIONS HAVE IMPROVED SLIGHTLY. WOULD EXPECT SOME SLOW
DETERIORATION THROUGH REMAINDER OF THE PRE-DAWN HOURS...THOUGH DO
NOT HAVE MUCH CONFIDENCE IN JUST HOW LOW. WORST CONDITIONS...VLIFR
IN SPOTS...HAVE GENERALLY HELD WEST AND SOUTHEAST OF THE CHICAGO
METRO TERMINALS WITH STRATUS/FOG HAVING ALSO SPREAD NORTHWEST INTO
RFD. HAVE ADJUSTED ORD/MDW AND GYY TO BE JUST A BIT MORE
OPTIMISTIC BASED ON TRENDS OF LAST SEVERAL HOURS.
RATZER
PREVIOUS DISCUSSION FROM 06Z...
LARGE AREA OF LOW STRATUS/FOG HAS EXPANDED NORTH-NORTHWESTWARD
ACROSS CHICAGO TERMINALS AS OF 0530Z...AND IS EXPECTED TO CONTINUE
TO SPREAD NORTHWEST INTO ROCKFORD WITHIN THE NEXT COUPLE HOURS.
COMBINATION OF PERSISTENT LIGHT MOIST SOUTH FLOW IN LOW AND A
STRONG INVERSION BASED AROUND 850 FT AGL PER RECENT AMDAR ASCENT
SOUNDINGS FROM ORD IS EXPECTED TO MAINTAIN POOR CONDITIONS THROUGH
MORNING. NOT MUCH NOTED TO HELP ERODE STRATUS SATURDAY MORNING...
WITH DECEMBER CLIMATOLOGY BACKED BY LOW SUN ANGLE AND SHORT
DAYLIGHT HOURS EXPECTED TO ALLOW ONLY SLOW EROSION PRIMARILY FROM
THE EDGES DURING THE DAY. TIMING OF IMPROVEMENT REMAINS A LOW
CONFIDENCE FORECAST...AND HAVE MADE NO BIG CHANGES FROM PREVIOUS
FORECAST THINKING. SOME GUIDANCE SUGGESTS REDEVELOPMENT AGAIN
SATURDAY EVENING...THOUGH INCREASE IN HIGH CLOUD COVER MAY HELP
PREVENT FROM COOLING/SATURATING SOMEWHAT.
WINDS THROUGH THE FORECAST PERIOD SHOULD REMAIN SOUTH...170 TO 200
DEG 10 KTS OR LESS.
RATZER
//ORD AND MDW CONFIDENCE...UPDATED 09Z...
* HIGH IN FOG AND STRATUS WITH LIFR CIGS AND IFR/LIFR VSBY
THROUGH AT LEAST MID MORNING SATURDAY.
* LOW IN EXACTLY HOW LOW VSBY DROPS...BUT HIGH IN FALLING TO AT LEAST
1SM.
* LOW IN TIMING IMPROVEMENT TO VFR LATER TODAY.
RATZER
//OUTLOOK FOR ORD/MDW FOR 12Z SUNDAY-12Z FRIDAY...UPDATED 00Z...
SUNDAY THROUGH THURSDAY...PRIMARILY VFR. SMALL DAY TO DAY CHANCE
OF IFR CIGS/FOG DURING LATE NIGHTS/MORNINGS.
IZZI
&&
.MARINE...
250 AM CST
HIGH PRESSURE MOVING EAST ACROSS THE UPPER OHIO VALLEY TO THE MID
ATLANTIC REGION TODAY...AND LOW PRESSURE MOVING FROM MANITOBA TO
HUDSON BAY...WILL ALLOW SOUTH-SOUTHWEST WINDS TO PERSIST ACROSS
LAKE MICHIGAN. THE GRADIENT WILL TIGHTEN DURING THE DAY IN
RESPONSE TO PRESSURE FALLS ASSOCIATED WITH THE CANADIAN LOW...
WITH SOUTHERLY WINDS INCREASING INTO THE 30 KT RANGE THIS
AFTERNOON INTO TONIGHT OVER THE NORTHERN PART OF THE LAKE. THE
GRADIENT WILL THEN WEAKEN SUNDAY AS A WEAK COLD FRONT SLIDES
SOUTHEAST ACROSS THE LAKE...WITH WINDS SHIFTING TO THE WEST-
NORTHWEST. WEAK HIGH PRESSURE WILL BUILD IN BEHIND THE FRONT
SUNDAY NIGHT INTO MONDAY...BEFORE THE PATTERN REVERTS TO LOW
PRESSURE LIFTING NORTHEAST ACROSS CANADA AND NORTH OF THE LAKES
AND BRINGS A RETURN TO SOUTH-SOUTHWEST WINDS INTO EARLY NEXT WEEK.
RATZER
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...DENSE FOG ADVISORY...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-ILZ010-
ILZ011-ILZ012-ILZ013-ILZ014-ILZ019-ILZ020-ILZ021-ILZ022-
ILZ023-ILZ032-ILZ033-ILZ039 UNTIL NOON SATURDAY.
IN...DENSE FOG ADVISORY...INZ001-INZ002-INZ010-INZ011-INZ019 UNTIL
NOON SATURDAY.
LM...NONE.
&&
$$
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FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
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WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
National Weather Service Lincoln IL
244 AM CST SAT DEC 5 2015
.SHORT TERM...(Today)
ISSUED AT 243 AM CST SAT DEC 5 2015
Dense fog continues to expand north and west early this morning as
the boundary layer flow remains out of the east and southeast. Have
expanded the Dense Fog advisory to include all counties except
Schuyler until Noon. Latest few runs of the HRRR suggest the fog
will edge west to Schuyler county just after 12z and then begin to
dissipate after sunrise. High pressure centered over Ohio will inch
slowly away from the area with the ridge axis forecast to extend
west into our area through much of the day. Forecast soundings
showing a very shallow moist layer at the surface trapped underneath
a strong low level inversion thru the day with our west and
southwest counties seeing the sun first with our eastern counties
not seeing any significant breaks until this afternoon, if then.
For what is usually a recipe for a big temperature bust, will use
continuity with respect to forecast highs this afternoon with a
very similar setup to what we experienced yesterday. Based off
that reasoning, will go fairly close to the highs obtained
yesterday afternoon, especially across the east where readings in
some areas didn`t get out of the 30s. Don`t have anything quite
that cool today as RUC soundings even in our far east were showing
several hours where we could see a little sunshine, unlike the
latest HRRR run which was showing the stratus and low visibilitiesholding
across our east throughout the afternoon. Our warmest readings
once again will be in the west where the mercury should top out in
the lower 50s, while roughly along and east of the I-55 corridor,
afternoon highs will be mostly in the 40s, with a few locations
over east central IL just getting to 40 degree later this
afternoon.
&&
.LONG TERM...(Tonight through Friday)
ISSUED AT 243 AM CST SAT DEC 5 2015
Low level inversion does not appear to be going away until Sunday,
when a shortwave currently located over Idaho and Utah arrives. SREF
probability guidance indicates the fog is likely to expand westward
once again this evening and cover most areas north of I-70. Would
not be surprised if another fog advisory is needed, but will wait to
see how much conditions can improve this afternoon first.
Aforementioned upper wave will close off as it crosses Illinois
Sunday afternoon. Have increased PoP`s to about 30% west of a Peoria
to Springfield line, mostly on the back side of the low, and
introduced 30% PoP`s across the southeast quarter of the forecast
area for evening as the low shifts into Indiana.
Remainder of the forecast period will be fairly mild for this time
of year, as the general upper flow remains of Pacific origin. Some
questions exist for late week, as one upper wave in particular digs
as it crosses the Dakotas. The ECMWF is more aggressive with this
digging and draws some colder air aloft southward from Manitoba,
producing a slower and more robust surface low/front Thursday night.
The GFS is much weaker and basically has a dry frontal passage.
Leaned a bit more toward the slower solution for now, but did not
make any significant changes to the initialized forecast grids due
to the uncertainty.
&&
.AVIATION...(For the 06Z TAFS through 06Z Saturday night)
ISSUED AT 1143 PM CST FRI DEC 4 2015
Will continue the dense fog for CMI/DEC/BMI/SPI and think the
dense fog will finally get into PIA around 08z based on satellite
trends showing edge of low clouds/fog pushing slowly north and
west toward the area. The dense fog will continue at all sites
overnight and likely into the morning hours as well. PIA and SPI
will improve first, being on the western edge of the LIFR/VLIFR
conditions. DEC/BMI/CMI will improve later, maybe early afternoon
as some eroding and mixing occurs. However, thinking the cigs
below 500 ft will continue at those sites during the afternoon but
vis will improve to around 2-3sm. Unfortunately, believe a return
to LIFR conditions will occur again tomorrow evening so have
continued low cigs and reduced vis to below 1sm at BMI/CMI, around
1sm for DEC, around 2sm for SPI and 3sm for PIA. These conditions
will occur early afternoon in the east and then later in the west.
Winds will be southeast through the period.
&&
.ILX Watches/Warnings/Advisories...
Dense Fog Advisory until noon CST today for ILZ027>031-036>038-
041>057-061>063-066>068-071>073.
&&
$$
SHORT TERM...Smith
LONG TERM...Geelhart
AVIATION...Auten
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
103 AM EST SAT DEC 5 2015
.SYNOPSIS...
ISSUED AT 100 AM EST SAT DEC 5 2015
AREAS OF DENSE FREEZING FOG WILL PERSIST OVERNIGHT AND BE SLOW TO
LIFT THIS MORNING. TEMPERATURES EARLY THIS MORNING SHOULD DROP TO
NEAR 30 DEGREES. SOME TEMPORARY CLEARING IS EXPECTED BY LATE TODAY
WITH HIGHS IN THE 40S.
&&
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 300 PM EST FRI DEC 4 2015
FAIRLY DRASTIC OVERALL TO GRIDS FOR TONIGHT INTO SATURDAY MORNING
TO REFLECT INCREASING CONCERNS FOR RAPID REDEVELOPMENT OF WIDESPREAD
STRATUS AND FOG (POSSIBLY DENSE) ACROSS THE AREA. VIS SAT AND
OBSERVATIONS SHOW SCOURING OUT OF STRATUS DECK CONTINUES...BUT WILL
LIKELY REACH THE END OF THIS OCCURRING IN THE NEXT HOUR OR 2 AS PEAK
HEATING AND MIXING DIMINISHES. DESPITE THE CLEARING A SLOW INCREASE
IN LOW LEVEL MSTR COMBINED WITH LIGHT WINDS AND MOSTLY CLEAR TO
CLEAR SKIES WILL SET THE STAGE FOR RAPID DEVELOPMENT OF STRATUS
ACROSS THE AREA THIS EVENING. HRRR HAS BEEN HANDLING OVERALL SETUP
QUITE WELL BOTH LAST NIGHT AND TODAY AND QUICKLY BRINGS STRATUS AND
DENSE FOG BACK IN BETWEEN 3 AND 6Z SAT. GRIDS NOW REFLECT A RETURN
TO CLOUDY SKIES BY LATE EVENING WITH PATCHY FOG
INITIALLY...EVENTUALLY GOING TO AREAS OF FOG. WHERE FULL CLEARING
HAS TAKEN PLACE...A MENTION OF PATCHY DENSE FREEZING FOG HAS BEEN
ADDED AS TEMPS DROP BELOW FREEZING ACROSS THE AREA AND GREATER
CONCENTRATION OF WATER DROPLETS MAY GIVE A LIGHT GLAZE ON ELEVATED
SURFACES. FOR NOW WILL HOLD OFF ON ANY HEADLINES AND DEFER TO EVE
SHIFT TO MONITOR TRENDS AS COULD END UP MAINLY THE STRATUS ISSUE AND
VSBYS BEHAVE THEMSELVES.
NEXT CHALLENGE WILL BE IF THE STRATUS/FOG CAN LIFT DURING THE DAY
SATURDAY AS INVERSION REMAINS IN PLACE. CLEARING MAY BE HIGHLY
DEPENDENT ON ACTUAL DEPTH OF THE STRATUS DECK. TODAY IT WAS ON
THE THINNER SIDE AND ALLOWED AT LEAST SOME MIXING. THIS MAY NOT BE
THE CASE TOMORROW AS RIDGE AXIS SHIFTS OVERHEAD AND POTENTIALLY
TRAPS THE LOW CLOUDS AND SOME FOG THROUGH THE DAY. FOR NOW WILL
KEEP WITH AT LEAST SOME CLEARING...BUT EXTENSIVE UPDATE CHANGES
MAY BE NEEDED IN LATER FORECASTS. WILL GO WITH GENERAL PERSISTENCE
ON TEMPS AS WELL WITH BUST POTENTIAL MODERATE TO HIGH.
&&
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 300 PM EST FRI DEC 4 2015
LONG TERM PERIOD BEGINS QUIETLY...WITH LARGE SCALE RIDGE AXIS
CENTERED EAST OF THE REGION SUNDAY AND UPPER TROF/CUTOFF LOW
APPROACHING THE REGION FROM THE WEST. CONTINUED WITH A DRY FORECAST
OF 14 POPS OR LESS SUNDAY NIGHT/EARLY MONDAY AS THIS SYSTEM PASSES
THROUGH THE REGION...WITH A BULK OF THE FORCING AND MOISTURE
REMAINING SOUTH OF THE REGION.
A ZONAL FLOW REGIME TAKES HOLD ACROSS THE CONUS THROUGH MUCH OF NEXT
WEEK. THE MAIN FORECAST CHALLENGE WILL BE EMBEDDED SHORTWAVES
TRACKING THROUGH THIS ZONAL FLOW REGIME AND POTENTIAL PRECIPITATION
FOR THE FORECAST AREA. LONG TERM MODEL SOLUTIONS DIFFER WITH THE
HANDLING OF THESE SYSTEMS. WENT WITH A CONSENSUS BLEND APPROACH
WHICH YIELDED SLIGHT CHANCE POPS WEDNESDAY THROUGH THE END OF THE
PERIOD. HONED THESE POPS DOWN TO WEDNESDAY AND WED NIGHT
TIMEFRAME...WHICH QUICK MOVING WAVE TRACKS SOMEWHERE THROUGH THE
REGION...BUT KEPT POPS LESS THAN 20 PERCENT. WENT WITH A CONTINUED
DRY FORECAST THURSDAY AND THURSDAY NIGHT...BUT KEPT THE CONSENSUS
BLEND SOLUTION FOR FRIDAY WITH VERY LOW CHANCE POPS. TOWARD THE END
OF NEXT WEEK...THE OVERALL PATTERN BECOMES MORE AMPLIFIED AS STRONG
EPAC UPPER JET BUCKLES...WITH DEEPER TROUGHING OVER THE WRN CONUS
AND DOWNSTREAM ERN CONUS RIDGING. WHEN THIS ENERGY EJECTS THROUGH
THE REGION SOMETIME TOWARDS THE END OF THE WEEK/NEXT WEEKEND...THIS
WOULD INCREASE PRECIPITATION CHANCES GREATLY. HOWEVER LONG RANGE
MODELS DIFFER GREATLY WITH TIMING/EVOLUTION OF THIS SYSTEM...WHICH
COULD BRING A DECENT RAINFALL TO THE AREA DEPENDING ON THE
EVOLUTION. FOR NOW...WITH STICK WITH THE LOW CHANCE POPS FOR
FRIDAY...BUT THIS WILL BE THE TIME PERIOD TO WATCH FOR THE NEXT
CHANCE OF A DECENT RAINFALL FOR THE REGION.
OTHERWISE...TEMPS THROUGH THE PERIOD WILL BE MILD FOR EARLY/MID
DECEMBER STANDARDS...WITH HIGHS IN THE LOW TO MID 40S SUNDAY THROUGH
TUESDAY...AND MID TO UPPER 40S AND POSSIBLE 50S LATER IN THE PERIOD.
LOW TEMPS THROUGH THE PERIOD WILL START OUT AT OR BELOW FREEZING SAT
NIGHT AND SUN NIGHT...THEN WARMING THROUGH THE 30S EACH NIGHT
THROUGH THE END OF THE PERIOD. THIS WOULD YIELD POTENTIAL AVERAGE
TEMPS NEARLY 10 DEGREES ABOVE NORMAL BY THE END OF THE FORECAST
PERIOD.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1234 AM EST SAT DEC 5 2015
MOISTURE AND LOW CLOUDS REMAIN TRAPPED UNDER THE BASE OF A
SUBSIDENCE INVERSION WHERE DAYTIME HEATING HAS BEEN INSUFFICIENT
TO MIX OUT THIS LAYER. EARLY TONIGHT...THE AREA OF LOW CLOUDS AND
FOG HAS EXPANDED RAPIDLY. GIVEN THE LATEST OBSERVATIONS AND
TRENDS...HAVE MADE TAFS MUCH MORE PESSIMISTIC WITH DENSE FREEZING
FOG BY LATE TONIGHT. MUCH UNCERTAINTY HOW MUCH SKIES WILL BE ABLE
TO CLEAR OUT...AND SUBSEQUENTLY THE POSSIBILITY OF THE RETURN OF
LOW CLOUDS AND FOG AGAIN TONIGHT. AT THIS POINT...GIVEN
PERSISTENCE IN AN STAGNANT PATTERN...HAVE INTRODUCED IFR CIGS
AFTER 03Z TONIGHT. AGAIN...THERE IS MUCH UNCERTAINTY WITH THIS
TIMING WITH THESE CONDITIONS.
&&
.UPDATE...
ISSUED AT 102 AM EST SAT DEC 5 2015
MOISTURE AND LOW CLOUDS REMAIN TRAPPED UNDER THE BASE OF A
SUBSIDENCE INVERSION WHERE DAYTIME HEATING HAS BEEN INSUFFICIENT
TO MIX OUT THIS LAYER. EARLY TONIGHT...THE AREA OF LOW CLOUDS AND
FOG HAS EXPANDED RAPIDLY. GIVEN THE LATEST OBSERVATIONS AND
TRENDS AND WITH COORDINATION OF SOME OF ADJACENT OFFICES HAVE
ISSUED A FREEZING FOG ADVISORY UNTIL 10 AM.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...FREEZING FOG ADVISORY UNTIL 10 AM EST /9 AM CST/ THIS MORNING
FOR INZ003>009-012>018-020-022>027-032>034.
MI...FREEZING FOG ADVISORY UNTIL 10 AM EST THIS MORNING FOR
MIZ077>081.
OH...FREEZING FOG ADVISORY UNTIL 10 AM EST THIS MORNING FOR OHZ001-
002-004-005-015-016-024-025.
LM...NONE.
&&
$$
SYNOPSIS...FISHER/SKIPPER
SHORT TERM...FISHER
LONG TERM...NG
AVIATION...SKIPPER
UPDATE...SKIPPER
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AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
406 AM EST SAT DEC 5 2015
LATEST UPDATE...
AVIATION
.SYNOPSIS...
ISSUED AT 320 AM EST SAT DEC 5 2015
HIGH PRESSURE WILL PRODUCE FAIR AND MILD WEATHER THROUGH THE
WEEKEND. HOWEVER AREAS OF DENSE FOG THIS MORNING WILL CAUSE
HAZARDOUS TRAVEL CONDITIONS. TEMPERATURES WILL CONTINUE TO AVERAGE
AT LEAST TEN TO FIFTEEN DEGREES ABOVE NORMAL THROUGH THE UPCOMING
WEEK.
&&
.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 320 AM EST SAT DEC 5 2015
A FREEZING FOG ADVISORY REMAINS IN EFFECT FOR ALL OF OUR FCST AREA
THROUGH 15Z THIS MORNING. SFC OBS/GROUND TRUTH REPORTS CONTINUE TO
INDICATE AREAS OF DENSE FOG ACROSS MUCH OF OUR FCST AREA. THIS IN
CONJUNCTION WITH SFC TEMPS AT OR BELOW FREEZING ACROSS PORTIONS OF
OUR AREA WILL RESULT IN HAZARDOUS TRAVEL CONDITIONS THROUGH MID
MORNING.
FOG WILL GRADUALLY DISSIPATE LATE THIS MORNING AND SKIES ARE
EXPECTED TO BECOME PARTLY TO MOSTLY SUNNY THIS AFTERNOON WITH
SUBSIDENCE UNDER THE HIGH PRESSURE RIDGE. IT WILL BECOME MILD AGAIN
TODAY WITH HIGH TEMPS REACHING THE MIDDLE TO UPPER 40S (00Z MET
NUMERICAL GUIDANCE MAXES ARE MUCH TOO COOL). THE HIGH PRESSURE RIDGE
WILL CONTINUE IN CONTROL OF THE WX PATTERN AND BRING FAIR WEATHER
THROUGH MONDAY.
.LONG TERM...(MONDAY NIGHT THROUGH FRIDAY)
ISSUED AT 320 AM EST SAT DEC 5 2015
THE SHORT STORY IS WARMER THAN NORMAL TEMPERATURES WILL BE FOLLOWED
MUCH WARMER THAN NORMAL TEMPERATURES LATER IN THE WEEK. WE WILL
TREND INTO A MUCH WETTER PATTERN AS WE HEAD TOWARD NEXT WEEKEND.
FOR THE MOST PART THE MODELS HAVE BEEN VERY CONSISTENT IN THE LARGE
SCALE DETAIL FOR THIS COMING WEEK. OUR VERY ACTIVE PACIFIC WAVE
TRAIN CONTINUES TO FEED SYSTEMS ON SHORE ABOUT EVERY TWO DAYS. WITH
THE SPLIT FLOW MOST OF THE PRECIPITATION HAS BEEN WELL NORTH IN
CANADA AND THIS COMING WEEK WE WILL SEE A LITTLE RAIN TRACK JUST
SOUTH OF MICHIGAN WITH THE SOUTHERN STREAM EARLY IN THE WEEK.
HOWEVER AS OUR VERY IMPRESSIVE 180 KNOT EAST ASIAN JET CORE (WE
HAVE BEEN FOLLOWING THIS ALL WEEK) GETS CLOSER TO WESTERN NORTH
AMERICA THE WAVES MOVING ON SHORE WILL AMPLIFY. THIS WILL
INCREASE THE FLOW OF GULF MOISTURE NORTH AND ALSO INCREASE JUST
HOW FAR NORTH THAT MOISTURE GETS.
IT SEEMS TO ME THE STORM NOW OFF THE WEST COAST (LOOKS GREAT ON THE
1 AM WATER VAPOR LOOPS...CHECK IT OUT OF YOU CAN) WILL BE OUR
WEDNESDAY SYSTEM. THIS ONE MAY HAVE ENOUGH WAVE LENGTH AS IT MOVES
TROUGH THE CENTRAL PLAINS TO GIVE US A FEW SHOWERS WEDNESDAY.
THERE WILL BE ONE MORE SYSTEM COMING THROUGH BEFORE THE SYSTEM WITH
THAT EAST ASIAN JET CORE OVER 180 KNOTS MOVES ONSHORE. THAT ONE
REACHES US IN THE FRIDAY TIME FRAME. THAT WILL BE MORE AMPLIFIEDTHAN
THE WEDNESDAY SYSTEM SO EXPECT A MORE WIDESPREAD RAIN EVENT WITH
THAT ONE.
MORE THAN LIKELY OUR TEMPERATURE FORECAST IS TO CONSERVATIVE... I
BELIEVE WE COULD SEE ACTUAL TEMPERATURE AS MUCH AS 5 TO 10 DEGREES
WARMER THAN WE ARE FORECASTING BY LATE IN THE PERIOD.
.WEEK TWO FORECAST...(SATURDAY THROUGH FRIDAY)
OF COURSE THE MAIN SHOW COMES THE NEXT WEEKEND INTO THE MIDDLE OF
THE FOLLOWING WEEK. BOTH THE ECMWF AND GFS SHOW THE AO AND NAO TENDING
TOWARD NEGATIVE VALUES THEN AND THE PNA GOING POSITIVE. ALL THAT
WOULD SUGGEST WESTERN RIDGE AND EASTERN TROUGH. THIS GOES WELL
WITH THE PROGRESSION OF THAT EAST ASIAN JET CORE. THE MAIN ENERGY
FOR THIS SYSTEM WILL COME TROUGH THE GREAT LAKES DURING THE
WEEKEND OF THE 12TH (SATURDAY). TIMING MAY BE SLOWER THAN I AM
SAYING BUT THE SYSTEM IN THE TIME FRAME OF SUNDAY THE 13TH COULD
BE A VERY DEEP SURFACE LOW WITH A LOT OF WIND AND A STRONG SURGE
OF EVERY WARM AIR. IT IS THIS SYSTEM THAT I THINK WILL BEING US
RECORD OR NEAR RECORD HIGHS IN THE MID 60S SATURDAY OR SUNDAY.
FOR THOSE WAITING FOR SNOW AND COLD... YOU MAY GET YOUR WISH BY THE
MIDDLE TO END OF THAT WEEK (THINK THE 15TH TO 18TH). THERE IS ONE
MORE SHORTWAVE THAT TRAILS THE MAIN SYSTEM. AS THAT MOVES INTO THE
PLAINS I DO BELIEVE WE WILL BE SEEING MUCH BETTER RIDGING OVER THE
WESTERN PLAINS AND MOUNTAIN STATES. THAT WILL FINALLY BRING IN 850
TEMPERATURES IN THE 15 BELOW RANGE INTO OUR AREA AND UNLIKE THE PAST
MONTH OR SO...THIS COLD PUSH WILL NOT LEAVE SO QUICKLY. THE GFS OUT
TO 16 DAYS HAS BEEN SHOWING THIS RUN AFTER RUN NOW FOR A WEEK. THE
CFSV2 ENSEMBLES SHOW SNOW COVER DOWN TO TENNESSEE BY FRIDAY THE
18TH. THIS HAS BEEN CONSISTENT IN THE CFSV2 FOR OVER A WEEK TOO.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 405 AM EST SAT DEC 5 2015
WIDESPREAD DENSE FOG HAD DEVELOPED AT GRR...AZO...BTL...LAN AND
JXN BUT THEN THE FOG MIXED OUT AT GRR. AZO IS BEGINNING TO SEE
VISIBILITIES GO UP TOO. SO...WHY DID THIS HAPPEN AND WILL IT FOG
IN AGAIN? LOOKING AT OUR MESO-ANALYSIS WINDS ARE MOSTLY FROM
SOUTHWEST AND FROM GRR TO THE LAKE SHORE TEMPERATURES INCREASE 38
AT GRR TO 41 NEAR HOLLAND. THIS STREAM WARMER AIR MOVING IN
LOWERS THE RELATIVE HUMIDITY AND MIXED OUT THE FOG.
MEANWHILE...OVER THE AZO TO BTL TO JXN AREA WINDS ARE MORE
SOUTHERLY AND AIR TEMPERATURES ARE MOSTLY NEAR FREEZING. THE DENSE
FOG GOES WELL SOUTH IN TO CENTRAL INDIAN AT 4 AM.
AS FOR WHAT I THINK WILL HAPPEN... THE RAP MODEL AND OUR BUKFIT
FOG TOOK SHOW THE FOG COMING BACK IN BY SUNRISE ONLY TO MIX OUT BY
NOON. SO I UPDATED THE TAFS TO SHOW THIS TREND. ALL TAF SITES
EXCEPT MKG SHOULD HAVE DENSE FOG FROM 13Z TO 15Z.
&&
.MARINE...
ISSUED AT 320 AM EST SAT DEC 5 2015
SOUTHERLY WINDS AROUND 5 TO 15 KTS WILL PRODUCE WAVE HEIGHTS
RANGING FROM 1 TO AS HIGH AS 4 FEET TODAY... HIGHEST UP AROUND BIG
AND LITTLE SABLE POINTS. WAVE HEIGHTS COULD BRIEFLY FLIRT WITH
SMALL CRAFT CRITERIA LATE THIS AFTERNOON AND TONIGHT NORTH OF
WHITEHALL BUT IT IS TOO MARGINAL FOR A SMALL CRAFT ADVISORY AT
THIS TIME.
&&
.HYDROLOGY...
ISSUED AT 1152 AM EST FRI DEC 4 2015
RIVERS ARE WELL WITHIN BANKS AND FALLING. WITH LITTLE
PRECIPITATION EXPECTED UNTIL AT LEAST THE LATTER HALF OF NEXT
WEEK... FLOODING CONCERNS ARE MINIMAL.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...FREEZING FOG ADVISORY UNTIL 10 AM EST THIS MORNING FOR
MIZ037>040-043>046-050>052-056>059-064>067-071>074.
LM...NONE.
&&
$$
SYNOPSIS...LAURENS
SHORT TERM...LAURENS
LONG TERM...WDM
AVIATION...WDM
HYDROLOGY...CAS
MARINE...LAURENS
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
1202 AM EST SAT DEC 5 2015
.AVIATION...
VERY LOW STRATUS/FOG HAS BEEN INCHING ITS WAY TOWARD SE MI THIS
EVENING WITHIN LOW LEVEL W-SW FLOW. ONGOING COOLING AND MOISTENING
IN THE BOUNDARY LAYER OVER SE MI SUGGESTS THE LOW CLOUDS AND FOG
WILL OVERSPREAD THE TERMINALS EARLY THIS MORNING. THERE IS A CONCERN
THAT THE DEGREE OF COOLING IN THE BOUNDARY LAYER WILL MAKE
CONDITIONS PRIME FOR SOME DENSE FOG. THIS SUPPORTS LOWERING BOTH
CEILINGS AND VISIBILITIES A LITTLE MORE FROM THE PREVIOUS FORECAST.
THE ONGOING ADVECTION OF VERY WARM AIR ABOVE THE INVERSION /925MB
TEMPS TO +8C/ WILL LEAD TO AN EXTREMELY DEEP LOW LEVEL INVERSION.
THIS WILL MAKE IT VERY DIFFICULT FOR THE LOW DECEMBER SUN ANGLE TO
MIX THIS MOISTURE OUT THIS AFTERNOON. THE HIGHER TERRAIN AROUND PTK
WILL BE DEEPER INTO THE INVERSION...LEADING TO A MORE SHALLOW MOIST
LAYER...LIKELY MAKING THESE LOCALS THE FIRST TO SEE THE MOISTURE MIX
OUT THIS AFTERNOON. GRADUAL EROSION OF THE CLOUDS SHOULD THEN TAKE
HOLD DURING THE COURSE OF THE AFTERNOON.
FOR DTW...EXTRAPOLATION FROM SATELLITE SUGGESTS THE LOW CLOUDS/FOG
ARRIVING AT METRO BETWEEN 08Z AND 09Z. THERE IS A POTENTIAL FOR
BOUNDARY LAYER COOLING TO ACCELERATE THE PACE OF THESE
CLOUDS...SUPPORTING AN 08Z ONSET TIME. THERE IS A CONSIDERABLE
DEGREE OF UNCERTAINTY WITH RESPECT TO TIMING THE DISSIPATION OF THIS
MOISTURE THIS AFTERNOON. THERE IS ACTUALLY A CHANCE THAT THE LOW
CLOUDS/FOG HOLD RIGHT INTO SAT NIGHT CONSIDERING THE LOW SUN ANGLE.
//DTW THRESHOLD PROBABILITIES...
* HIGH IN CEILINGS BELOW 5000 FT THIS MORNING AND AFTERNOON. LOW
THIS EVENING.
* MEDIUM IN CIGS/VSBY FALLING BELOW 200 FT AND/OR 1/2SM THIS
MORNING.
&&
.PREV DISCUSSION...ISSUED 1001 PM EST FRI DEC 4 2015
UPDATE...
REMNANT VERY LOW STRATUS DECK LODGED WITHIN THE BACKGROUND OF WEAK
SURFACE RIDGING NOW ENCOMPASSING MUCH OF INDIANA BEGINNING A MORE
PROGRESSIVE OUTWARD EXPANSION AS NOCTURNAL COOLING STRENGTHENS. 1000-
975 MB RH FIELDS ON BOTH THE HRRR AND RAP CONCUR WITH BOTH THE
CURRENT PLACEMENT OF THIS CLOUD DECK AND THE EVENTUAL NORTHEAST
MOVEMENT TOWARD THE FORECAST AREA OVERNIGHT. THESE TRENDS WOULD
POINT TOWARD TAKING A DECIDELY MORE PESSIMISTIC OUTLOOK ON CLOUD
COVER NEARLY AREAWIDE FOR THE EARLY-MID MORNING PERIOD. ELEMENT OF
SHALLOW FOG WITHIN THIS NEAR SURFACE MOISTURE PLUME AS WELL. COOLING
PROCESS MAKING THE MOST OF THIS LONG DURATION OF OPEN SKY EARLY
TONIGHT...SOME LOCALES ALREADY DOWN INTO THE LOWER 30S. OVERALL LOW
TEMPERATURE FORECAST IN LINE WITH CURRENT TRENDS...SOME REALIGNMENT
OF THE TEMPERATURE CURVE GOING FORWARD BASED ON EXPECTATIONS FOR
CLOUD COVER TO EVENTUALLY CAP THIS COOLING /PARTICULARLY SOUTHWEST
SECTIONS/.
PREV DISCUSSION...ISSUED 318 PM EST FRI DEC 4 2015
DISCUSSION...
THE MAIN WEATHER NARRATIVE REMAINS THE EXTENDED RUN INTO NEXT
WEEKEND...OF ABOVE NORMAL TEMPERATURES...A HIGH AMOUNT OF SUNSHINE
FOR DECEMBER...AND THE PREDOMINATELY DRY CONDITIONS.
DECISIVE CLEARING CAME TO FRUITION THIS MORNING ON THE BACKS OF VERY
ACTIVE SUBSIDENCE IN THE 925-700MB LAYER. THIS FRESH ROUND OF
SUBSIDENCE OCCURRED ALONG THE SOUTHERN PERIPHERY OR IN THE ZONE OF AVA
BEHIND A SHORTWAVE THAT CUT THROUGH THE GREAT LAKES LAST NIGHT. FOR
TONIGHT...MODELED MOISTURE PROFILES MAINTAIN HIGHER AMBIENT MOISTURE
IN THE BOUNDARY LAYER WHICH INTRODUCES SOME UNCERTAINTY. WITH THAT
STATED...OVERALL THERMODYNAMIC STRUCTURE AND STEADY LOWERING OF THE
INVERSION BASE DURING THE NEXT 12 TO 36 HOURS SUGGESTS THAT NOW THAT
CLOUDS HAVE BROKEN IT WILL BE DIFFICULT TO DEVELOP NEW CLOUD.
INSTEAD...THE POTENTIAL DOES EXIST FOR CLOUD TO THE SOUTH TO EXPAND
IN COVERAGE BACK NORTHWARD POSSIBLY IMPACTING AREAS SOUTH OF M 59
LATER TONIGHT. DUE TO THE INVERSION STRUCTURE...FORECASTER
PREFERENCE IS SIDED TO POTENTIAL FOG DEVELOPMENT LATE TONIGHT RATHER
THAN STRATUS. WITH THIS IN MIND THE BETTER POTENTIAL REMAINS ACROSS
THE SOUTHERN CWA AND INTO ST CLAIR COUNTY WHERE THE BOUNDARY LAYER
GRADIENT WINDS WILL BE ALLOWED TO RELAX UNDER BETTER SURFACE HIGH
PRESSURE.
LESS IN THE WAY OF STRATUS/FOG IS EXPECTED TO BEGIN THE DAY SATURDAY
THAN THIS MORNING. THIS WILL SET THE STAGE FOR A WONDERFUL EARLY
DECEMBER SATURDAY ACROSS ALL OF SOUTHEASTERN MICHIGAN. THE BIG
QUESTION FOR SATURDAY IS WHAT WILL HIGH TEMPERATURES BE WITH A VERY
STRONG STABLE LAYER LOWERING AND SQUASHING MIXING HEIGHTS OVER THE
REGION. MODELS HAVE BEEN UNDERFORECASTING HIGHS A TOUCH THE PAST TWO
DAYS...AS A RESULT...INCREASED HIGHS INTO THE LOWER 50S MANY
AREAS...UPPER 40S NEAR THE WATER AND LOWER SURFACE PRESSURE
LOCATIONS. WITH AMOUNT OF GRADIENT FLOW THAT IS NORMALLY IN PLACE
THIS TIME OF YEAR...A PRETTY ATYPICAL FORECAST WITH THE INVERSION ON
THE GROUND. SUFFICE IT TO SAY WITH PARAMETERIZATIONS AND NEGLIGIBLE
VERTICAL RESOLUTION IN THE MODEL DATA...THERE ISN`T A WHOLE LOT OF
CONFIDENCE IN THE MAX TEMPERATURE GUIDANCE.
A SIZABLE MIDLEVEL SHORTWAVE AND PSEUDO CUTOFF IS FORECASTED TO
ARRIVE OVER THE CENTRAL GREAT LAKES BY LATE SUNDAY. WHILE MODELS
HAVE SOUTHEASTERN MICHIGAN ON THE FAVORABLE SIDE FOR MIDLEVEL
FORCING...PRIMARILY DEFORMATION...FORECAST DATA IS OVERWHELMINGLY IN
SUPPORT OF A MOISTURE STARVED SYSTEM. SUSPECT...HIGH CLOUD TO
INCREASE DURING THE DAY ON SUNDAY BUT NOT IN TIME TO CLASSIFY THE
DAY AS CLOUDY OR OVERCAST. HIGHS ON SUNDAY ARE AGAIN EXPECTED TO
REACH THE MIDDLE 40S.
QUIET EXTENDED PERIOD IS IN STORE FOR SOUTHEAST MICHIGAN. SURFACE
HIGH PRESSURE AND UPPER LEVEL RIDGING WILL REMAIN IN PLACE ACROSS
THE MIDWEST RESULTING IN DRY AND PLEASANT CONDITIONS. A SHORTWAVE
TROUGH PIVOTING THROUGH THE GREAT LAKES REGION ON WEDNESDAY NIGHT
WILL BRING THE NEXT CHANCE OF RAIN TO THE REGION. AT THIS TIME HAVE
ONLY INCLUDED A SLIGHT CHANCE /20 PERCENT/ FOR WEDNESDAY NIGHT INTO
THURSDAY. HIGH TEMPERATURES REMAIN IN THE MID TO UPPER 40S FROM
MONDAY THROUGH NEXT THURSDAY. LOW TEMPERATURES DROP INTO THE LOW TO
MID 30S OVERNIGHT.
MARINE...
SLOWLY WARMING SOUTH-SOUTHWEST FLOW PREDOMINATELY IN THE 10 TO 15
KNOT RANGE WILL BE IN PLACE THROUGH THE WEEKEND OVER THE CENTRAL
GREAT LAKES...LEADING TO STABLE PROFILES AND LOW WAVES. A FEW GUSTS
UP AROUND 20 KNOTS ARE EXPECTED ACROSS CENTRAL PORTIONS OF LAKE
HURON. HIGH PRESSURE WILL EXPAND BACK ACROSS THE GREAT LAKES EARLY
NEXT WEEK...PROVIDING LIGHT WINDS MONDAY INTO AT LEAST TUESDAY.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MICHIGAN WATERS OF LAKE ERIE...NONE.
&&
$$
AVIATION.....SC
UPDATE.......MR
DISCUSSION...CB/RK
MARINE.......SF
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS ST LOUIS MO
330 AM CST SAT DEC 5 2015
.SHORT TERM: (Through Late This Afternoon)
Issued at 330 AM CST Sat Dec 5 2015
Once again, fog is the primary concern for the short term forecast
this morning. An expansive area of fog is advecting westward toward
the Mississippi River from Illinois and it looks likely to envelop
much of the STL Metro area before sunrise. Have already expanded
the dense fog advisory issued yesterday evening into east central
Missouri. HRRR and NARRE-TL look to have a pretty good handle on
the fog so far this morning...although they might be a little bit
too aggressive with the westward-southwestward expansion.
Regardless, both models keep visibility down through 14-15Z.
Improvement is pretty rapid between 16-18Z, so the timing of the
advisory still looks pretty good. Temperatures today should be
similar to yesterday, though some of the cooler readings over
central Illinois yesterday will likely expand further west-southwest
today due to the greater areal coverage of the fog today.
Carney
.LONG TERM: (Tonight through Friday)
Issued at 330 AM CST Sat Dec 5 2015
An extended period of above average temps continues to look likely
for much of next week as the polar jet, with very few exceptions,
remains to our north. The flow will overall be low amplitude,
facilitating a progressive movement to any systems, and indeed, our
area will be treated to a series of storm systems originating over
the Pacific that will be quick hitting, which will incidentally,
limit their ability to moisten the column sufficiently to allow
pcpn.
The first system is slated for Sunday, and this looks to be the one
where confidence is highest that it will produce pcpn for some
areas. Models have come together nicely on timing now that it is
over land and can be sampled better, ranging from beginning Sunday
morning over northeast and central MO, to exiting southwest IL by
late Sunday evening. There is also good consensus on track, with
the strongest lift associated with the core of the system expected
over northern MO and central IL, and have placed highest PoPs in
these areas as a result--corresponding to our northern CWA. Even
then, moisture will struggle with this system, with its relatively
fast movement, northern track, very dry column already in place, and
no help whatsoever from low level flow. So highest PoPs for this
system look to be just below 50% in the north, trailing to slight
chance 20% in southern MO and IL. Pcpn-types should be all rain
with warm air aloft and above freezing surface temps.
Additional fast moving Pacific systems will slide thru, Monday
night, Tuesday night, and again Thursday-Friday, but with marginal
conditions at best and specific tracks enough in doubt (large enough
model spreads) whereby they will need all the lift they can muster
to generate pcpn, leaned dry on the forecast for much of next week
for now, with PoPs possibly needed down the road as track confidence
increases.
Otherwise, very mild week on tap after Sunday, with what should be
daytime maxes at least in the 50s, possibly 60s, and nighttime mins
above freezing.
A pattern change looks set to occur for the third week of December,
with large height falls and a longwave TROF setting up over the
central CONUS. This should open the way for cold air intrusions
heading towards Christmas that we have not really seen thus far this
late autumn and early winter.
TES
&&
.AVIATION: (For the 06z TAFs through 06z Saturday Night)
Issued at 1134 PM CST Fri Dec 4 2015
For COU/UIN...Winds will remain sely to ssely thru the TAF period
just above 10 kts for UIN and around 8 kts for COU.
Specifics for KSTL/KSUS/KCPS: Focus continues to be FG impacts.
Have moved back timing at all sites. Given the dewpoint spread at
SUS, believe FG will develop shortly. At STL/CPS, temps have not
dropped as quickly as previously thought due to continued mixing.
However, given potential for river FG to develop and the area of
dense FG over IL moving wwd, will move back timing of onset and
keep mention in the TAF for now.
Tilly
&&
.LSX WATCHES/WARNINGS/ADVISORIES:
MO...Dense Fog Advisory until noon CST today FOR Jefferson MO-St.
Charles MO-St. Louis City MO-St. Louis MO-Ste. Genevieve MO.
IL...Dense Fog Advisory until noon CST today FOR Bond IL-Calhoun IL-
Clinton IL-Fayette IL-Greene IL-Jersey IL-Macoupin IL-
Madison IL-Marion IL-Monroe IL-Montgomery IL-Randolph IL-
St. Clair IL-Washington IL.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
1148 PM CST FRI DEC 4 2015
.UPDATE:
Issued at 824 PM CST Fri Dec 4 2015
Have issued a dense fog advisory for the eastern counties as an
area of dense fog is spreading westward this evening now that the
boundary layer is becoming saturated after sunset. Visibilities
are already down to 3SM at Salem and are 1/4SM at Effingham and
Taylorville. Visibility guidance from the RAP and experimental
HRRR suggests that the dense fog may spread back to the
Mississippi river overnight, so may need to expand the advisory
again this evening. Where there are temperatures below freezing,
the fog may deposit some icing on roads which could produce some
slick spots. Rest of the forecast still looks on track.
Britt
&&
.SHORT TERM: (Through Late Tonight)
Issued at 321 PM CST Fri Dec 4 2015
Late this afternoon, an area of fog/stratus was located over
IL/IN near the center of a surface high. Some models show the
existing fog/stratus backbuilding overnight, especially an
expansion into southwest IL. This scenario does not seem
unreasonable given the presence of fog/stratus last night, the
observed slow erosion of fog/stratus today, moisture trapped
beneath an inversion noted on BUFKIT soundings, and the expected
wx conditions tonight (particularly the light winds and initially
clear skies over the eastern CWA which will promote radiational
cooling). If it develops, the thickest fog/stratus would be
expected over southwest and southern IL. Farther west, southerly
surface winds should remain strong enough to interfere with
widespread fog formation, although patchy fog cannot be ruled
out, especially with any breaks in the approaching cirrus
associated with a weak disturbance.
Kanofsky
.LONG TERM: (Saturday through Next Friday)
Issued at 321 PM CST Fri Dec 4 2015
The warming trend noted today (temperatures in the 50s by 21z)
will continue tomorrow. A stronger vort max then approaches the
region tomorrow night and could bring some light rain to the area
on Sunday, but moisture remains limited. This forecast maintains
fairly low PoPs for Sunday due to the limited moisture. The
latest model runs are in better agreement with a more progressive
solution, and most models have the upper vort center well east of
the area by 12z Mon. Persistent southerly to southwesterly flow
will help temperatures rebound into the mid-upper 50s during the
middle and late part of the week. A few other disturbances are
forecast to move across the central CONUS during the middle and
late part of next week, possibly bringing light pcpn to MO/IL.
Kanofsky
&&
.AVIATION: (For the 06z TAFs through 06z Saturday Night)
Issued at 1134 PM CST Fri Dec 4 2015
For COU/UIN...Winds will remain sely to ssely thru the TAF period
just above 10 kts for UIN and around 8 kts for COU.
Specifics for KSTL/KSUS/KCPS: Focus continues to be FG impacts.
Have moved back timing at all sites. Given the dewpoint spread at
SUS, believe FG will develop shortly. At STL/CPS, temps have not
dropped as quickly as previously thought due to continued mixing.
However, given potential for river FG to develop and the area of
dense FG over IL moving wwd, will move back timing of onset and
keep mention in the TAF for now.
Tilly
&&
.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...Dense Fog Advisory until noon CST Saturday FOR Bond IL-Clinton
IL-Fayette IL-Marion IL-Montgomery IL-Washington IL.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
335 AM CST SAT DEC 5 2015
.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 335 AM CST SAT DEC 5 2015
PCPN CHANCES TONIGHT AND TEMPS THE NEXT FEW DAYS ARE THE MAIN FCST
CONCERNS.
TROUGH OVER THE ROCKIES REMAINS PROGRESSIVE WITH 12 HOUR HEIGHT
FALLS AT 00Z AS HIGH AS 110 METERS AT KGGW. WEAKER HEIGHT FALLS
EXTENDED BACK TO THE S AND SW INTO SRN CA AND AZ. WATER VAPOR LOOP
IN COMBINATION WITH RECENT RUC MODEL INITIALIZATIONS SHOWED THE
TROUGH AXIS FROM NEAR THE ID/WY BORDER SWD INTO AZ. SFC ANLYS AT
09Z DEPICTED CDFNT FROM ERN ND INTO WRN NE.
EXPECT INCREASING/THICKENING CLOUD COVER FOR THE AREA TODAY AS THE
TROUGH OVER THE ROCKIES MOVES EWD. RAIN CHANCES SHOULD HOLD OFF
UNTIL AFTER 6 PM...THEN INCREASE AS LIFT CAUSES MID LEVEL
SATURATION. HIGH RESOLUTION GFS SEEMS TO HAVE A DECENT HANDLE ON
TIMING. PCPN AMOUNTS OVERNIGHT SHOULD BE FAIRLY LIGHT...AND FCST
SOUNDINGS SUGGEST PCPN TYPE REMAINING LIQUID. LINGERED A SLIGHT
CHANCE OF LIGHT RAIN IN SWRN IA AND THE SERN TIP OF NE. WEAK
RIDGING ALOFT MOVES IN LATER SUN...AND CLOUDS WILL DECREASE.
GENLY USED A BLEND OF AVAILABLE MOS GUIDANCE...WITH HIGHEST WEIGHT
GIVEN TO 00Z GFS.
.LONG TERM...(MONDAY NIGHT THROUGH FRIDAY)
ISSUED AT 335 AM CST SAT DEC 5 2015
KEPT THIS PERIOD MAINLY DRY. A FAST MOVING SHORTWAVE TROUGH WILL
MOVE INTO THE CNTRL PLAINS TUE...BUT MOISTURE LOOKS LIMITED FOR
OUR AREA. CHANCES ARE BEST FROM THE DKTS INTO MN AND NRN IA...BUT
WILL NEED TO WATCH THIS IN FUTURE MODEL RUNS. ANOTHER SHORTWAVE
TROUGH MOVES ACRS THE AREA THU...BUT AGAIN MOISTURE LOOKS LIMITED
FOR ERN NE AND SWRN IA. TEMPS SHOULD BE FAIRLY MILD THROUGH THE
PERIOD...WITH THU PROBABLY THE WARMEST DAY FOR KLNK AND KOMA.
&&
.AVIATION...(06Z TAFS FOR KOFK...KLNK AND KOMA.)
ISSUED AT 1141 PM CST FRI DEC 4 2015
BRISK SOUTH WINDS TONIGHT 10 TO 16 KTS WITH VARIABLE GUSTS. DID
MENTION LOW LEVEL WIND SHEAR WITH AXIS OF H9 WINDS WITH 40 TO 50KT
JET. VFR CONDITIONS TONIGHT WITH INCREASING CLOUDS FOR SATURDAY.
THE WINDS DECREASE AS THE FRONT APPROACHES WITH A FROPA AND WINDS
SWITCHING AROUND TO THE NORTH AT KOFK AROUND 00Z.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
SHORT TERM...MILLER
LONG TERM...MILLER
AVIATION...ZAPOTOCNY
AREA FORECAST DISCUSSION
NWS BUFFALO NY
304 AM EST SAT DEC 5 2015
.SYNOPSIS...
HIGH PRESSURE WILL BUILD INTO THE REGION TODAY WITH A GRADUAL
RETURN TO SUNSHINE AND ABOVE AVERAGE TEMPERATURES. THE CLEAR
SKIES AND WARM TEMPERATURES WILL CONTINUE SUNDAY AND RIGHT THROUGH
THE FIRST HALF OF NEXT WEEK AS HIGH PRESSURE REMAINS IN CONTROL.
&&
.NEAR TERM /THROUGH TONIGHT/...
A WIDESPREAD LOW STRATUS DECK LODGED UNDERNEATH A STEEP
SUBSIDENCE INVERSION WITHIN THE BACKGROUND OF WEAK SURFACE RIDGING
CONTINUING TO ENCOMPASSING MUCH OF WESTERN NEW YORK. 1000-975 MB
MOISTURE FIELDS ON THE HRRR AND RAP CONCUR WITH THE CURRENT
PLACEMENT OF THIS CLOUD DECK. CLOUDS WILL BE STUBBORN TO CLEAR
WITH CURRENT TRENDS POINTING TOWARD TAKING A DECIDEDLY MORE
PESSIMISTIC OUTLOOK ON CLOUD COVER NEARLY AREAWIDE THROUGH THE
MORNING PERIOD. ELEMENT OF SHALLOW FOG WITHIN THIS NEAR SURFACE
MOISTURE PLUME AS WELL.
STRATUS/FOG SHOULD ERODE FOR THE MOST PART BY AFTERNOON...ALTHOUGH
COULD CONTINUE TO LINGER ACROSS INTERIOR SECTIONS EAST OF LAKE
ONTARIO. INCREASING SUNSHINE ALONG WITH DEVELOPING WARM AIR
ADVECTION PATTERN SHOULD GET AFTERNOON TEMPERATURES IN THE LOWER
50S ON THE LAKE PLAINS OF WESTERN NEW YORK AND MID TO UPPER 40S
ACROSS HIGHER TERRAIN AND THE EASTERN LAKE ONTARIO REGION.
BY SUNDAY...SURFACE HIGH PRESSURE AND MID LEVEL RIDGING WILL SHIFT
OFF THE MID-ATLANTIC AND NEW ENGLAND COASTS. AMPLE SUNSHINE ALONG
WITH A SOUTHERLY FLOW AND 850 MB TEMPERATURES NEAR +6C WILL SUPPORT
HIGHS REACHING THE LOWER TO MID 50S.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
SURFACE HIGH PRESSURE AND MID-LEVEL RIDGING WILL SHIFT OFF THE MID-
ATLANTIC AND NEW ENGLAND COASTS THROUGH SUNDAY BEFORE A SURFACE
TROUGH AND MID-LEVEL CLOSED LOW PASS SOUTH OF OUR FORECAST AREA ON
MONDAY. MODEL DIAGNOSTIC DISCUSSION REFERS TO HIGH CONFIDENCE WITH
THE STRENGTH AND PLACEMENT OF THIS CLOSED UPPER LOW AND ITS
ASSOCIATED EFFECT ON LOCAL SENSIBLE WEATHER. ANY SYNOPTIC LIFT AND
MOISTURE WORTH MENTIONING WILL BE COLLOCATED WITH THE LOW CENTER...
WELL TO OUR SOUTH...LEAVING WESTERN AND CENTRAL NEW YORK WITH FAIR
WEATHER THROUGH THE BEGINNING OF NEXT WEEK. MAINLY CLEAR SKIES WILL
PROMOTE PLENTY OF SUNSHINE SUNDAY AND MONDAY WITH ONLY A FEW HIGH
CLOUDS STREAMING NORTH FROM THE SOUTHERN SYSTEM ON MONDAY NIGHT.
SOUTHERLY FLOW AND 850MB TEMPS OF +8C WILL SUPPORT HIGHS REACHING
INTO THE LOWER TO MIDDLE 50S ON SUNDAY WITH UPPER 40S TO LOW 50S
EAST OF LAKE ONTARIO. THEN A NORTHERLY SHIFT TO THE WINDS AND COLD
ADVECTION ON MONDAY WILL KNOCK 850MB TEMPS BACK TOWARD 0C KEEPING
SURFACE HIGHS ABOUT 10F COOLER.
GOOD RADIATIONAL COOLING EACH NIGHT WILL ALLOW LOWS TO RANGE FROM
THE LOWER TO MIDDLE 30S NEAR THE LAKES TO THE UPPER 20S WELL INLAND.
LIGHT WINDS WILL ALLOW RIVER VALLEY FOG IN THE SOUTHERN TIER VALLEYS
WHICH COULD MAKE FOR SOME SLICK ROADWAYS IN AREAS WHERE SURFACE
TEMPS ALSO FALL BELOW FREEZING.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
A WAVY PACIFIC FLOW IS EXPECTED TO GENERALLY KEEP MILD TEMPERATURES
AND BENIGN WEATHER THROUGH NEXT WEEK. 04/12Z GFS AND ECMWF MODELS
ARE NOT WELL ALIGNED WITH THE 500MB PATTERN WITH EACH MODEL SHOWING
A DIFFERENCE IN TIMING AND LOCATION OF SUBTLE SHORTWAVE TROUGHS
MOVING ACROSS THE CONUS. THIS LEADS TO A LOW CONFIDENCE FORECAST FOR
MORE DEFINITIVE TIMING OF ANY MINOR PRECIPITATION EVENTS THAT MAY
IMPACT OUR FORECAST AREA.
IT APPEARS THAT A DEEPENING STORM OFF THE EAST COAST TUESDAY WILL
NOT BE A THREAT TO WESTERN AND CENTRAL NEW YORK AT THIS TIME
ALTHOUGH THE 04/12Z ECMWF HAS SHIFTED A BIT FURTHER NORTH WITH THE
TRACK OF THE CLOSED 500MB LOW. AFTER THIS THE FORECAST ONLY INCLUDES
SLIGHT CHANCE POPS FROM WEDNESDAY NIGHT INTO FRIDAY DUE TO THE POOR
MODEL AGREEMENT. DAYTIME TEMPERATURES WILL RUN ON THE MILD SIDE FOR
THIS TIME OF YEAR WITH OVERNIGHT LOWS CLOSER TO SEASONAL NORMALS.
HIGHS WILL RANGE FROM THE MID 40S TO AROUND 50 EACH DAY WITH
OVERNIGHT LOWS RANGING IN THE MID 30S NEAR THE LAKES TO UPPER 20S
INLAND.
&&
.AVIATION /08Z SATURDAY THROUGH WEDNESDAY/...
WIDESPREAD STRATUS DECK WILL STUBBORNLY PERSIST WITH MOST
LOCATIONS SEEING MVFR CIGS...BUT SOME IFR CIGS ACROSS THE HIGHER
ELEVATIONS OF THE SOUTHERN TIER AND THE TUG HILL. EXPECT MAINLY
STATUS QUO THROUGH THE EARLY MORNING...EXCEPT FOR MAYBE CIGS
LOWERING OF ANOTHER 500 FEET OR SO. IN ADDITION... LOCATIONS
ACROSS THE SOUTHERN TIER MAY START TO SEE IFR VSBY RESTRICTIONS
AS THE STRATUS DECK LOWERS CLOSER TO THE HIGH TERRAIN.
CLEARING FROM WEST TO EAST SHOULD BE FAIRLY ROBUST SATURDAY
MORNING...WITH VFR CONDITIONS AND LIGHT WINDS PREDOMINATE BY
AFTERNOON.
OUTLOOK...
SUNDAY TO WEDNESDAY...VFR.
&&
.MARINE...
HIGH PRESSURE WILL BUILD INTO THE LOWER LAKES THIS WEEKEND AND
REMAIN IN PLACE THROUGH THE MIDDLE OF NEXT WEEK...PROVIDING A RARE
EXTENDED STRETCH OF LIGHT WINDS AND FLAT WAVE ACTION ON THE LOWER
LAKES.
&&
.CLIMATE...
TEMPERATURES ACROSS WESTERN AND NORTH CENTRAL NEW YORK HAVE AVERAGED
WELL ABOVE NORMAL SINCE HALLOWEEN...LARGELY DUE TO A POWERFUL EL
NINO EVENT THAT IS IN PLACE OVER THE EQUATORIAL PACIFIC. THE
STRENGTH OF THE CURRENT EL NINO IS SIMILAR TO THE HISTORIC ONE FROM
1997-98 WHEN OUR REGION BASKED IN ONE OF THE MILDEST WINTERS OF THE
PAST SIXTY YEARS.
THE MILDER WEATHER DID HAVE AN IMPACT ON LAKE SNOWS THAT SEASON.
SNOWFALL FOR THAT PARTICULAR WINTER AVERAGED WELL BELOW NORMAL...
WITH LAKE EFFECT AREAS ONLY RECEIVING ABOUT HALF AS MUCH SNOW AS
USUAL. THE LACK OF SNOWFALL WAS NOT AS PERCEPTIBLE IN NON-LAKE
EFFECT AREAS THOUGH AS A FAVORABLE SYNOPTIC STORM TRACK ALLOWED FOR
NEAR NORMAL AMOUNTS...WITH THE FINGER LAKES REGION ACTUALLY
EXPERIENCING MORE SNOW THAN NORMAL.
DURING THE PAST SIX WEEKS...THERE HAVE BEEN TWO NOTICEABLE
HEMISPHERIC PATTERNS THAT HAVE SUPPORTED THE MILD WEATHER. THE
FIRST IS DIRECTLY RELATED TO STRONG EL NINOS...THAT BEING AN
ANOMALOUSLY STRONG ASIAN/NORTH PACIFIC JET. NOT ONLY IS THIS JET
STRONGER NORMAL BUT IS APPEARS TO BE DISPLACED SEVERAL HUNDRED
MILES FURTHER NORTH. THE EFFECTS OF THIS ARE TWO FOLD. IT
SUPPRESSES THE DEVELOPMENT OF A WEST COAST RIDGE...WHICH WAS
DOMINANT THE PAST TWO WINTERS...AND IT ALSO HELPS TO FLOOD THE
BULK OF NORTH AMERICA WITH PACIFIC MODIFIED AIR. WHILE KEEPING
PACIFIC BASED AIR IN PLACE...THIS PATTERN ALSO BLOCKS ANY ATTEMPT
AT ANY REAL COLD AIR FROM MAKING ITS WAY SOUTH. TRUE COLD AIR UP
TO THIS POINT HAS BEEN LOCKED IN PLACE BETWEEN THE CANADIAN
ARCHIPELAGO AND SIBERIA...OR POLEWARD OF 60N.
THE OTHER KEY HEMISPHERIC FEATURE HAS BEEN THE PERSISTENCE OF AN
ICELANDIC LOW. THIS PATTERN ENHANCES THE MID AND UPPER LEVEL JET AS
IT EXITS NORTH AMERICA...THUS KEEPING A STRONG LOW AMPLITUDE FLOW
ACROSS THE NORTH ATLANTIC. WITHOUT ANY HIGH LATITUDE BLOCKING (EX
GREENLAND BLOCK)...THE STRONG WEST TO EAST JET CAN REMAIN DOMINANT.
THE RESULT IS PERSISTENT `MILD` WEATHER ACROSS THE EASTERN HALF OF
NORTH AMERICA AS WELL AS EUROPE (POSITIVE NAO TRAIT).
MEDIUM AND LONG RANGE GUIDANCE CONTINUES TO KEEP THIS GENERAL
PATTERN IN PLACE FOR THE FORESEEABLE FUTURE...SO A CHANGE TO THE
GENERAL MILD PATTERN IS NOT ANTICIPATED THROUGH AT LEAST MID MONTH.
ANY COLD AIR THAT IS NEEDED FOR SIGNIFICANT LAKE EFFECT WOULD HAVE
TO BE `MANUFACTURED` LOCALLY...WHICH IS NOT SOMETHING THAT IS
TYPICALLY EXPERIENCED FOR MESOSCALE EVENTS SUCH AS LAKE EFFECT.
SUCH A PROCESS IS MORE FAVORABLE FOR LARGER SYNOPTIC SYSTEMS.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...TMA
NEAR TERM...TMA
SHORT TERM...WCH
LONG TERM...SMITH
AVIATION...TMA
MARINE...TMA
CLIMATE...RSH
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1220 AM CST SAT DEC 5 2015
.UPDATE...
ISSUED AT 1218 AM CST SAT DEC 5 2015
NO CHANGES REQUIRED TO THE FORECAST.
UPDATE ISSUED AT 929 PM CST FRI DEC 4 2015
NO SIGNIFICANT UPDATES TO THE GOING FORECAST THIS EVENING. STRONG
SOUTHERLY WINDS AHEAD OF A COLD FRONT IN EASTERN NORTH DAKOTA
WITH LIGHT TO MODERATE SOUTHWEST TO WEST WINDS OVER WESTERN NORTH
DAKOTA WILL KEEP TEMPERATURES RATHER UNIFORM ACROSS THE FORECAST
AREA TONIGHT...EVEN OVER THE REMAINING SNOWPACK OVER THE FAR SOUTH
CENTRAL INTO THE JAMES RIVER VALLEY. INCREASING CLOUDS TRACKING
NORTHEAST FROM SOUTH DAKOTA WILL ALSO HELP KEEP TEMPERATURES FROM
FALLING LIKE THE PAST FEW NIGHTS OVER THE SNOWPACK. UPDATED LATEST
SENSIBLE WEATHER ELEMENTS AND INTERPOLATED TO A CONSENSUS OF SHORT
TERM HOURLY TEMPERATURES FOR THE OVERNIGHT PERIOD. RESULTING IN
VERY FEW CHANGES FROM THE PREVIOUS FORECAST.
UPDATE ISSUED AT 627 PM CST FRI DEC 4 2015
A WEAK COLD FRONT WILL TRAVERSE THE FORECAST AREA TONIGHT. STRONG
SOUTHERLY FLOW OVER THE JAMES RIVER VALLEY EARLY THIS EVENING WILL
DIMINISH BY LATE EVENING AS FLOW SHIFTS MORE SOUTHWEST...AND
EVENTUALLY WEST SATURDAY MORNING.
THE SOUTHWEST TO WEST FLOW SHOULD KEEP TEMPERATURES RATHER UNIFORM
TONIGHT COMPARED TO PREVIOUS NIGHTS...EVEN OVER THE DECAYING
SNOWPACK. THE TURBULENCE IN THE LOW LEVELS SHOULD ALSO HELP TO
INHIBIT ANY FOG FORMATION WHERE SNOWMELT OCCURRED DURING THE DAY.
FOR THE EVENING UPDATE...ONLY SOME MINOR ADJUSTMENTS TO SKY COVER
AND POPULATED THE LATEST SENSIBLE WEATHER ELEMENTS.
&&
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 320 PM CST FRI DEC 4 2015
MILD AND QUIET WEATHER WILL CONTINUE THROUGH SATURDAY.
AS OF 21 UTC...IT IS APPARENT THAT THE LOW-LEVEL INVERSION IS ONLY
SLOWLY BEING ERODED IN SOUTHERLY FLOW...AS SURFACE GUSTS ARE BEING
HELD UNDER 30 KT EVEN IN THE JAMES RIVER VALLEY. FORECAST SOUNDING
PROFILES FROM THE RAP AND HRRR CONTINUE TO SUPPORT WINDS AROUND
60 KT WITHIN 2000 FT AGL THROUGH EARLY EVENING IN EAST CENTRAL ND
AND SO WE WILL HAVE TO MONITOR FOR STRONGER GUSTS...BUT THE CHANCE
OF ADVISORY-TYPE GUSTS APPEARS TO BE DWINDLING.
A MODEST COLD FRONT WILL CROSS THE AREA TONIGHT...TURNING WINDS TO
THE WEST...AND COOLING THE AIR MASS A BIT BY SATURDAY WHEN 850-MB
TEMPERATURES ARE EXPECTED TO DROP TO +1 TO +3 C. HOWEVER...GIVEN
THE FAVORABLE LOW-LEVEL WESTERLY FLOW AND CONTINUED EROSION OF THE
SNOW PACK...WE STILL EXPECT HIGHS IN THE 40S F IN MANY PLACES ON
SATURDAY. IT ALSO APPEARS THAT THE NEAR-SURFACE LAYER WILL BE TOO
TURBULENT TO SUPPORT FOG FORMATION TONIGHT IN AREAS THAT HAVE HAD
SNOWMELT DURING THE DAY.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 320 PM CST FRI DEC 4 2015
THE MAIN HIGHLIGHTS IN THE LONG TERM PERIOD ARE ABOVE NORMAL HIGH
TEMPERATURES THROUGH THE PERIOD...WITH HIGHS IN THE 40S AND SOME 50S
ESPECIALLY SUNDAY AND WEDNESDAY. A COOLING TREND INITIATES FRIDAY
AND CONTINUES THROUGH THE UPCOMING WEEKEND. ALTHOUGH COOLER
CONDITIONS EXPECTED FRIDAY...HIGH TEMPERATURES STILL REMAIN ABOVE
NORMAL WITH HIGHS 35F TO 40F. THE OVERALL PATTERN OF A NEAR ZONAL
FLOW CONTINUES WITH QUICK MOVING SHORTWAVES AND ASSOCIATED SURFACE
FEATURES SLIDING ACROSS WESTERN AND CENTRAL NORTH DAKOTA. THE MAIN
DIFFERENCE ON THE 12Z GFS/ECMWF MODELS RUNS TODAY IS A MORE
WIDESPREAD CHANCE OF MOSTLY RAIN SHOWERS ON TUESDAY ACROSS WESTERN
AND CENTRAL NORTH DAKOTA. ALTHOUGH SOME SNOW SHOWERS ARE POSSIBLE
DURING THE EARLY MORNING. ANOTHER FAIRLY WEAK SHORTWAVE IS SLATED
FOR THURSDAY INTO THURSDAY NIGHT....WITH A POTENTIALLY STRONGER
SHORTWAVE FRIDAY INTO THE WEEKEND. HOWEVER IT IS EVIDENT JUST FROM
THE GFS ENSEMBLE HEIGHTS THAT NEXT WEEKENDS SHORTWAVE HAS A LOT OF
UNCERTAINTY...WITH SEVERAL POSSIBLE SOLUTIONS. THE SUPERBLEND
CURRENTLY HAS A SLIGHT CHANCE/CHANCE OF RAIN AND SNOW FRIDAY/FRIDAY
NIGHT.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1218 AM CST SAT DEC 5 2015
VFR CONDITIONS AT ALL TAF SITES THROUGH THE TAF PERIOD WITH WEST
WINDS DEVELOPING AT ALL SITES BY THE EARLY MORNING HOURS.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...AJ
SHORT TERM...CJS
LONG TERM...KS
AVIATION...AJ
AREA FORECAST DISCUSSION...
NWS PORTLAND OR
850 PM PST FRI DEC 4 2015
.SYNOPSIS...THE NEXT MOIST FRONTAL SYSTEM AFFECTS THE REGION
TOMORROW. THE FRONT IS EXPECTED TO AFFECT MOSTLY THE NORTH COAST AND
COASTAL MOUNTAINS ON SATURDAY...THEN SWING INLAND AS A COLD FRONT
LATE SATURDAY INTO SUNDAY FOR ANOTHER ROUND OF SIGNIFICANT RAINS AND
COASTAL WINDS. A MORE SIGNIFICANT AND WETTER FRONT IS EXPECTED
SUNDAY NIGHT INTO MONDAY...WHICH WILL BRING MORE STRONG COASTAL
WINDS AND MAY BRING POTENTIAL FOR SOME FLOODING ON AREA RIVERS AND
STREAMS. AN ADDITIONAL VERY WET SYSTEM IS EXPECTED TOWARD THE MIDDLE
OF NEXT WEEK AS THIS MILD AND VERY WET PATTERN CONTINUES.
&&
.SHORT TERM...TONIGHT THROUGH MONDAY...WATER VAPOR SATELLITE IMAGERY
REVEALS A SHORTWAVE RIDGE TEMPORARILY SHIFTING OVER THE PACIFIC
NORTHWEST...WHILE A WARM FRONT IS ALREADY BEGINNING TO SPREAD HIGH
CLOUDS OVER THE REGION. CLOSER TO THE SURFACE...DOPPLER RADAR SHOWS A
FEW SHOWERS CONTINUE TO DRIFT NORTHEASTWARD ACROSS THE REGION...AND
ARE INCREASINGLY BECOMING CONFINED TO THE COAST AND HIGHER TERRAIN.
WITH THE LOWER ATMOSPHERE STABILIZING OVERNIGHT...EXPECT THE GENERAL
TREND OF DECREASING SHOWERS TO CONTINUE. THE 00Z SLE SOUNDING
MEASURED A WET BULB ZERO HEIGHT OF 3700 FT SO ANY SHOWERS IN THE
HIGHER TERRAIN WILL LIKELY ALLOW LIGHT SNOW TO ACCUMULATE ON CASCADE
PASSES.
MODELS REMAIN IN GOOD AGREEMENT THAT THE AFOREMENTIONED WARM FRONT
CURRENTLY SPREADING HIGH CLOUDS OVER THE REGION WILL CONTINUE
EASTWARD OVERNIGHT AND SPREAD STEADY RAIN ACROSS MUCH OF NORTHWEST
OREGON AND SOUTHWEST WASHINGTON LATE TONIGHT AND EARLY SATURDAY.
LATEST HRRR GUIDANCE SUGGESTS RAIN WILL SPREAD ONTO THE COAST BETWEEN
3 AND 5 AM AND INTO THE WILLAMETTE VALLEY BETWEEN 6 AND 8 AM. WHILE
POPS WERE INCREASED FOR INTERIOR LOCATIONS...GLOBAL MODELS REMAIN
LESS AMBITIOUS WITH RAIN CHANCES FOR LATE TONIGHT AND SATURDAY
MORNING SO POPS WERE GENERALLY HELD IN THE HIGH END CHANCE TO LOW END
LIKELY RANGE FOR THE WILLAMETTE VALLEY EVEN THOUGH THE HRRR WOULD
SUGGEST MOST OF THE REGION WILL SEE A WET START TO SATURDAY.
EAST TO WEST PRESSURE GRADIENTS WILL INCREASE NOTABLY ACROSS THE
REGION LATER TONIGHT AND SATURDAY. THIS SHOULD RESULT IN EASTERLY
WINDS PICKING UP ONCE AGAIN IN THE WESTERN COLUMBIA RIVER GORGE WITH
GUSTS OF AT LEAST 30 TO 50 MPH SATURDAY. THIS WILL ALSO ALLOW SNOW
LEVELS TO HANG NEAR THE CURRENT LEVEL OF 3500 TO 4000 FT ACROSS THE
SOUTH WASHINGTON CASCADES AND FAR NORTH OREGON CASCADES INTO SATURDAY
MORNING. WHILE QPF STILL DOES NOT LOOK IMPRESSIVE TOMORROW...WE MAY
SEE AN INCH OR TWO OF SNOW...POSSIBLY A BIT MORE IN THE SOUTH
WASHINGTON CASCADES...IN THE MORNING BEFORE THE BULK OF THE WARM
FRONTAL PRECIPITATION PUSHES NORTH OF OUR HIGHER TERRAIN AND WARMER
TEMPERATURES ALOFT ALLOW SNOW LEVELS TO RISE INTO THE 5500 TO 6500 FT
RANGE SATURDAY AFTERNOON/NIGHT. GIVEN THE OFFSHORE PRESSURE
GRADIENTS...SUSPECT THE COLDER WILL BE A BIT MORE STUBBORN TO EXIT
THAN PREVIOUSLY THOUGHT FOR LOCATIONS EAST AND NORTH OF MOUNT HOOD.
MEANWHILE...A TRAILING COLD FRONT ORIENTED FROM SOUTHWEST TO
NORTHEAST WILL SLOWLY DRIFT EASTWARD TOWARDS THE COAST
SATURDAY...BEFORE PUSHING ASHORE LATE SATURDAY NIGHT. THE MAIN STORY
WITH THIS SYSTEM WILL BE THE STRONG SOUTH WINDS THAT DEVELOP OUT
AHEAD OF IT ALONG THE OREGON AND WASHINGTON COASTS. MODELS AGREE 65
TO 75KT 925 MB SOUTH WINDS WILL DEVELOP OFF THE OREGON COAST SATURDAY
MORNING AND CONTINUE THROUGH MUCH OF SATURDAY NIGHT. THIS HAS BROUGHT
CONCERN THAT HIGH WINDS MAY SURFACE ALONG THE COAST...BUT GIVEN
PRESSURE GRADIENTS REMAIN SOLIDLY OFFSHORE SATURDAY AND EVEN MOST OF
SATURDAY NIGHT...SUSPECT MANY LOCATIONS WILL EXPERIENCE WIND GUSTS OF
50 MPH OR LESS. HOWEVER...CANNOT RULE OUT A FEW OF THE HEADLANDS LIKE
CAPE DISAPPOINTMENT AND CAPE MEARES GUSTING AROUND 60 MPH OR POSSIBLY
HIGHER...BUT SUSPECT THIS MAY END UP MORE THE EXCEPTION THAN THE
RULE AT THIS POINT. THE MOST FAVORABLE TIME FOR HIGHER WINDS TO
SURFACE ALONG THE COAST WILL LIKELY BE SATURDAY EVENING. IN
ADDITION...THIS SYSTEM WILL BRING A ROUND OF SOLID RAIN TO THE
REGION SATURDAY NIGHT...ON THE ORDER OF A QUARTER TO HALF AN INCH TO
THE WILLAMETTE VALLEY...AND 1 TO 2 INCHES OF RAIN FOR COASTAL AREAS
AND HIGHER TERRAIN. SNOW LEVELS WILL FALL BEHIND THE FRONT INTO THE
4500 FT AND 5500 FT RANGE SUNDAY...BUT DECREASING SHOWERS ON SUNDAY
SHOULD KEEP SNOW ACCUMULATIONS ACROSS THE HIGHER CASCADES FAIRLY
LIGHT.
THE BIGGER WEATHER STORY WILL ARRIVE SUNDAY NIGHT AND EARLY MONDAY AS
A MORE POTENT FRONT LIKELY PUSHES SOUTHEASTWARD ACROSS THE REGION.
AMAZINGLY...THIS STORM SYSTEM IS STILL SOUTH OF THE WESTERN PORTION
OF THE ALEUTIAN ISLANDS. WHILE WINDS ALOFT WITH THE SUNDAY
NIGHT/EARLY MONDAY STORM SYSTEM WILL LIKELY BE SIMILAR TO THE
SATURDAY/SATURDAY NIGHT STORM SYSTEM...APPROXIMATELY 75KT AT
925MB...PRESSURE GRADIENTS APPEAR MUCH MORE FAVORABLE FOR STRONGER
WINDS TO MIX DOWN TO THE SURFACE ALONG THE COAST AND IN THE COAST
RANGE. HIGH WIND PRODUCTS WILL LIKELY BE NEEDED. THERE MAY EVEN BE A
PERIOD OF BREEZY SOUTH WINDS EARLY MONDAY IN THE WILLAMETTE VALLEY
ALTHOUGH THE PORTLAND METRO MAY END UP BATTLING EAST WINDS. IN
ADDITION...MODELS DEPICT 850-1000MB IVT VALUES IN THE 250-300 G/KGS
RANGE WITH AN ORIENTATION MORE PERPENDICULAR THAN PARALLEL TO THE
COASTLINE. THIS SHOULD RESULT IN A 9-15 HOUR PERIOD OF STEADY RAIN
ACROSS NORTHWEST OREGON AND SOUTHWEST WASHINGTON DURING THIS TIME
WITH SOME LOCATIONS IN THE COAST RANGE AND CASCADES LIKELY RECEIVING
AT LEAST 4 TO 7 INCHES OF RAIN. WHILE NAEFS RETURN INTERVAL GUIDANCE
SUGGESTS IVT VALUES WITH THIS STORM SYSTEM OCCUR ON AVERAGE ABOUT
ONCE EVERY OTHER YEAR TO EVERY COUPLE OF YEARS...IT ALSO SUGGESTS
ANOTHER COMPARABLE STORM SYSTEM MAY ARRIVE MIDWEEK...WHICH MAY RESULT
IN SOME FLOOD CONCERNS. GIVEN THIS IS AN ENSEMBLE BASED APPROACH...IT
CERTAINLY BRINGS SOME PAUSE...AS WELL AS CONFIDENCE THAT WE ARE IN
STORE FOR A PERIOD OF NOTABLE WET WEATHER. THE CURRENT HYDROLOGIC
OUTLOOK COVERS THIS WELL. /NEUMAN
.LONG TERM...MONDAY NIGHT THROUGH FRIDAY. ACTIVE WEATHER PATTERN
CONTINUES INTO NEXT WEEK. WE GET SOMEWHAT OF A BREAK MONDAY NIGHT
INTO TUESDAY...WITH ONLY A FEW SHOWERS STILL LINGERING AROUND THE
AREA. DURING THIS TIME THE MOISTURE PLUME FROM THE MONDAY SYSTEM
SHIFTS NORTH OF OUR AREA...BEFORE DROPPING BACK SOUTH WITH THE NEXT
LOW PRESSURE SYSTEM TUESDAY AFTERNOON INTO WEDNESDAY. THE MODELS
HAVE A LOT OF MOISTURE WITH BOTH OF THESE SYSTEMS...SO WE ARE
ANTICIPATING A VERY WET WEEK WITH SIGNIFICANT ACCUMULATIONS LIKELY
THROUGH WEDNESDAY. DUE TO THE TROPICAL AIRMASS SOURCING THE MOISTURE
FOR THESE SYSTEMS...SNOW LEVELS REMAIN UP ABOVE 7000 FT THROUGH THE
FIRST HALF OF NEXT WEEK. SNOW LEVELS DROP BACK DOWN TO BELOW PASS
LEVELS BEHIND THE TUESDAY-WEDNESDAY SYSTEM...WITH ACTIVE WEATHER
PATTERN CONTINUING INTO THE WEEKEND. THEREFORE...SNOW COULD IMPACT
TRAVEL THROUGH THE CASCADES STARTING WEDNESDAY AFTERNOON THROUGH THE
END OF THE WEEK. THE SYSTEMS LATER IN THE WEEK DON`T HAVE THE LONG
MOISTURE FETCH LIKE THE MONDAY-WEDNESDAY SYSTEMS...SO RAINFALL
AMOUNTS SHOULD BE LESS LATER IN THE WEEK. -MCCOY
&&
.AVIATION...PRIMARILY VFR CONDITIONS TONIGHT. THERE IS A SMALL
CHANCE FOR MVFR OR IFR CONDITIONS IN PATCHY FOG LATE IN THE NIGHT
AFTER 07Z. PREVAILING CIGS LATER TONIGHT...AFTER 11Z...WILL BEGIN TO
COME DOWN INTO THE LOW END OF VFR CATEGORY AS THE NEXT FRONTAL
SYSTEM APPROACHES. CONDITIONS EXPECTED TO REMAIN VFR THROUGH THE
DAY...BUT THERE IS A CHANCE FOR COASTAL AREAS TO SEE TEMPORARY MVFR
CONDITIONS.
KPDX AND APPROACHES...GENERALLY VFR CONDITIONS AT KPDX THROUGH THE
DAY SAT.
&&
.MARINE...A STRONG FRONTAL SYSTEM WILL GENERATE STORM FORCE WINDS
OVER THE WATERS LATE TONIGHT THROUGH SATURDAY. INCREASING SOUTH
WINDS WILL BUILD WIND WAVES AND A FRESH SOUTH SWELL WITH COMBINED
SEAS REACHING 20 FT BY SUNRISE SATURDAY. SEAS ARE EXPECTED TO BUILD
TO 20 TO 24 FT RANGE SATURDAY AFTERNOON. SOUTH WINDS WILL DECREASE
LATE SATURDAY NIGHT AND BE BELOW 25 KT BY SUNRISE SUNDAY.
THE SEAS WILL BRIEFLY DIP BACK INTO THE TEENS SUNDAY BEFORE A LARGE
WEST SWELL BUILDS SUNDAY EVENING. THIS SWELL WILL BRING SEAS BACK
ABOVE 20 FT SUNDAY EVENING. MODELS FORECAST THE SWELL TO PEAK AROUND
21 FT AT 17 SECONDS LATE SUNDAY NIGHT. THIS SWELL WILL GENERATE
LARGE AND DANGEROUS BREAKING WAVES IN THE SURF ZONE THROUGH MONDAY
MORNING. THE LARGE WESTERLY SWELL COINCIDES WITH ANOTHER ROUND OF
STRONG WINDS SUN NIGHT AND MONDAY AS THE NEXT FRONT MOVES IN.
THE LARGE S SWELL COUPLED WITH LARGE LOCALLY GENERATED WIND WAVES AND
FRESH SOUTHERLY SWELL WILL MAKE FOR CHAOTIC AND DANGEROUS SEAS.
THERE IS ANOTHER CHANCE FOR GALES OR STORM FORCE WINDS TUESDAY.
&&
.PQR WATCHES/WARNINGS/ADVISORIES...
OR...HIGH WIND WARNING FROM 10 AM SATURDAY TO 2 AM PST SUNDAY FOR
CENTRAL OREGON COAST-NORTH OREGON COAST.
HIGH SURF ADVISORY FROM 7 PM SUNDAY TO 9 AM PST MONDAY FOR
CENTRAL OREGON COAST-NORTH OREGON COAST.
WA...HIGH WIND WARNING FROM 10 AM SATURDAY TO 2 AM PST SUNDAY FOR
SOUTH WASHINGTON COAST.
HIGH SURF ADVISORY FROM 7 PM SUNDAY TO 9 AM PST MONDAY FOR
SOUTH WASHINGTON COAST.
PZ...SMALL CRAFT ADVISORY FOR WINDS UNTIL 2 AM PST SATURDAY FOR
WATERS FROM CAPE SHOALWATER WA TO CASCADE HEAD OR FROM 10
TO 60 NM-WATERS FROM CASCADE HEAD TO FLORENCE OR FROM 10 TO
60 NM.
STORM WARNING FROM 2 AM SATURDAY TO 2 AM PST SUNDAY FOR WATERS
FROM CAPE SHOALWATER WA TO CASCADE HEAD OR FROM 10 TO 60 NM-
WATERS FROM CASCADE HEAD TO FLORENCE OR FROM 10 TO 60 NM.
SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 2 AM PST SATURDAY
FOR WATERS FROM CAPE SHOALWATER WA TO CASCADE HEAD OR FROM
10 TO 60 NM-WATERS FROM CASCADE HEAD TO FLORENCE OR FROM 10
TO 60 NM.
SMALL CRAFT ADVISORY FOR ROUGH COLUMBIA RIVER BAR UNTIL
6 PM PST SATURDAY.
SMALL CRAFT ADVISORY FOR WINDS UNTIL 6 AM PST SATURDAY FOR
COASTAL WATERS FROM CAPE SHOALWATER WA TO CASCADE HEAD OR
OUT 10 NM-COASTAL WATERS FROM CASCADE HEAD TO FLORENCE OR
OUT 10 NM.
STORM WARNING FROM 6 AM SATURDAY TO 2 AM PST SUNDAY FOR COASTAL
WATERS FROM CAPE SHOALWATER WA TO CASCADE HEAD OR OUT 10 NM-
COASTAL WATERS FROM CASCADE HEAD TO FLORENCE OR OUT 10 NM.
SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 6 AM PST SATURDAY
FOR COASTAL WATERS FROM CAPE SHOALWATER WA TO CASCADE HEAD
OR OUT 10 NM-COASTAL WATERS FROM CASCADE HEAD TO FLORENCE
OR OUT 10 NM.
&&
$$
INTERACT WITH US VIA SOCIAL MEDIA
WWW.FACEBOOK.COM/NWSPORTLAND
WWW.TWITTER.COM/NWSPORTLAND
THIS DISCUSSION IS FOR NORTHWEST OREGON AND SOUTHWEST WASHINGTON
FROM THE CASCADE CREST TO 60 NAUTICAL MILES OFFSHORE. THE AREA IS
COMMONLY REFERRED TO AS THE FORECAST AREA.
AREA FORECAST DISCUSSION
NWS AUSTIN/SAN ANTONIO TX
332 AM CST SAT DEC 5 2015
.SHORT TERM (TODAY THROUGH SUNDAY)...
COOL MORNINGS WITH PLEASANT AFTERNOON TEMPERATURES EXPECTED TODAY
AND SUNDAY WITH SOME CLOUDS MIXED IN ACROSS THE RIO GRANDE VALLEY.
TEMPERATURES WILL RETURN TO NEAR AND SLIGHTLY ABOVE NORMAL SUNDAY
WITH HIGHS REACHING INTO THE MID TO UPPER 60S.
WATER VAPOR AND RAP ANALYSIS DEPICT A WEAK SHORTWAVE RIDGE OVER
TEXAS AND THE GULF COASTAL WATERS THAT IS ALLOWING FOR WEAK
MOISTURE RETURN IN THE 925-700MB LAYER. THE MAIN WEAK MOISTURE
TONGUE IS CONFINED TO THE RIO GRANDE VALLEY AS IT POOLS AGAINST
THE SIERRA DEL BURRO RANGE. AS A RESULT...EXPECT LOW CLOUDS TO
DEVELOP THROUGH THE MORNING HOURS ACROSS THE RIO GRANDE VALLEY
THAT WILL SLOWLY BREAK UP THROUGH THE DAY. LOCATIONS EAST OF U.S.
HIGHWAY 83 WILL REMAIN MOSTLY SUNNY WITH ONLY HIGH CLOUDS
STREAMING OVERHEAD. AREAS SEEING MORE CLOUDS OUT WEST WILL NOT
WARM AS MUCH AS CENTRAL AND EAST LOCATIONS WITH A NICE REBOUND INTO
THE LOW TO MID 60S EXPECTED TODAY. MAVMOS ALONG WITH SUPPORT FROM
RAW MODEL SOUNDING GUIDANCE APPEARS TO BE THE BEST ROUTE FOR
MAXIMUM HIGHS TODAY. MIXING HEIGHTS WILL TOP OUT NEAR 2-2.2KFT
NEAR 9-10C THAT WILL SUPPORT THESE HIGHER VALUES VS. THE SLIGHTLY
COOLER MET/ECSMOS. DID TRIM 1F DEGREE OFF MAX HIGHS FOR KDRT
GIVEN THE CLOUD INTERFERENCE THROUGH AT LEAST THE LATE MORNING.
EXPECT A NEAR COPY FOR SUNDAY WITH SOME MORNING CLOUDS ACROSS THE
RIO GRANDE VALLEY AGAIN AND TEMPERATURES AREAWIDE LIKELY 1-3F
DEGREES WARMER IN THE AFTERNOON. SOME LOCATIONS ACROSS THE COASTAL
PLAINS AND NEAR KSAT COULD PUSH THE 70F DEGREE MARK. A WEAK
DRYLINE WILL SHIFT THROUGH ON SUNDAY USHERING IN DRIER AIR WITH
N/NW WINDS AND ONLY LIMITED MID-LEVEL CLOUDS. NO COLD AIR IS
ASSOCIATED WITH THIS BOUNDARY AND THUS WE WILL CONTINUE TO WARM
THROUGH THE AFTERNOON DESPITE THE NORTH WINDS.
&&
.LONG TERM (MONDAY THROUGH FRIDAY)...
NO HAZARDS APPEAR LIKELY THROUGH THE LONG TERM WITH PLEASANT AND
ABOVE NORMAL TEMPERATURES EXPECTED THROUGH AT LEAST THURSDAY. RAIN
CHANCES WILL INCREASE GOING INTO NEXT SATURDAY AHEAD OF A STRONGER
COLD FRONT AND MID-LVL SYSTEM.
FROM EARLY NEXT WEEK TO MID WEEK...THE REGION WILL REMAIN SOUTH OF
THE ACTIVE JET STREAM AND VOID OF AIRMASS CHANGES. SURFACE HIGH
PRESSURE WILL REMAIN OVER THE NORTHERN GULF THROUGH MID-WEEK AND
WEAK SOUTHWEST FLOW ALOFT. PWATS WILL BE IN THE 0.4"-0.8" RANGE
AS WEAK SOUTH SURFACE WINDS ATTEMPT TO BRING HIGHER MOISTURE TO
THE REGION. BY THURSDAY...A STRONGER SHORTWAVE TROUGH ACROSS THE
CENTRAL PLAINS WILL PUSH A WEAK FRONT NEAR THE HILL COUNTRY BUT
ONLY LIMITED RAIN CHANCES FOR THE COASTAL PLAINS ARE EXPECTED
WHERE PWATS WILL RECOVER TOWARDS 1.3".
A MORE POWERFUL SYSTEM WILL APPROACH THE BIG BEND LATE FRIDAY
INTO THE WEEKEND THAT MAY AID IN SOME SCATTERED SHOWERS AND STORMS.
THE BEST DYNAMICS AND FORCING SILL APPEAR TO BE NORTH AND EAST
WHERE THE BETTER RAIN CHANCES WILL BE. PWAT RECOVER STILL APPEARS
LOW TO MODEST AT BEST AND WILL ADVERTISE 20-30% FOR NOW AND WATCH
THE MODEL EVOLUTION FOR THIS TIME FRAME.
&&
.PRELIMINARY POINT TEMPS/POPS...
AUSTIN CAMP MABRY 65 42 67 40 66 / 0 0 0 0 0
AUSTIN BERGSTROM INTL AIRPORT 64 39 66 37 65 / 0 0 0 0 0
NEW BRAUNFELS MUNI AIRPORT 66 41 67 40 67 / 0 0 0 0 0
BURNET MUNI AIRPORT 63 41 63 37 64 / 0 0 0 0 0
DEL RIO INTL AIRPORT 63 42 66 41 66 / 0 0 0 0 0
GEORGETOWN MUNI AIRPORT 62 43 64 35 64 / 0 0 0 0 0
HONDO MUNI AIRPORT 65 40 68 38 66 / 0 0 0 0 0
SAN MARCOS MUNI AIRPORT 64 40 66 40 65 / 0 0 0 0 0
LA GRANGE - FAYETTE REGIONAL 65 43 67 42 66 / 0 0 0 0 0
SAN ANTONIO INTL AIRPORT 65 42 68 42 66 / 0 0 0 0 0
STINSON MUNI AIRPORT 66 43 69 42 67 / 0 0 0 0 0
&&
.EWX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
MESOSCALE/AVIATION...10
SYNOPTIC/GRIDS...ALLEN
AREA FORECAST DISCUSSION
NWS PUEBLO CO
458 AM MST SAT DEC 5 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 458 AM MST SAT DEC 5 2015
AN UPPER LEVEL TROF WILL BE MOVING ACROSS THE STATE TODAY. THIS
SYSTEM WILL BRING SOME SNOW TO THE CONTDVD THRU THE DAY...WITH THE
BEST CHANCES BEING OVER THE CENTRAL MTNS. SNOW ACCUMULATIONS ALONG
THE CONTDVD WILL BE LIGHT...WITH MAYBE 2-3 INCHES OVR THE CENTRAL
MTNS. PCPN WILL SPREAD EASTWARD TODAY...WITH LIGHT SNOW
ACCUMULATIONS EXPECTED OVER THE EASTERN MTNS...MAINLY THIS
AFTERNOON. BY LATE MORNING A COLD FRONT WILL MOVE INTO EL PASO
COUNTY AND THEN CONTINUE SOUTHWARD THRU THE PLAINS THRU THE EARLY
AFTERNOON...BRINGING GUSTY NORTHERLY WINDS TO THE AREA. THE FORECAST
MODELS HAVE BEEN CONSISTENT IN BRINGING PCPN TO EL PASO AND TELLER
COUNTIES LATE THIS MORNING AND THIS AFTERNOON. THE NAM AND HRRR ALSO
SHOW THE POTENTIAL FOR SOME ISOLD PCPN ALONG THE I-25 CORRIDOR OVR
PUEBLO...HUERFANO AND WRN LAS ANIMAS COUNTIES. LOOKS LIKE LITTLE
CHANCE FOR PCPN OVR THE FAR SERN PLAINS. TEMPS WILL BE COOLER
TODAY...BUT HIGHS SHOULD GENERALLY STILL BE A LITTLE ABOVE AVERAGE.
THE UPR TROF MOVES OUT OF THE STATE IN THE EARLY EVENING HOURS...AND
BY LATE EVENING PCPN CHANCES SHOULD END WITH CLEARING SKIES.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 458 AM MST SAT DEC 5 2015
OVERALL...IT STILL APPEARS THAT A MILD AND RELATIVELY DRY METEOROLOGICAL
PATTERN SHOULD BE NOTED OVER THE MAJORITY OF THE FORECAST DISTRICT
DURING THE BALANCE OF THE LONGER TERM...ALTHOUGH INCREASING
PRECIPITATION CHANCES ARE ANTICIPATED BY LATER IN THE WEEK AS A
SYSTEM IMPACTS THE REGION.
MAIN METEOROLOGICAL ISSUES DURING THE LONGER TERM WILL BE
TEMPERATURES...THE POTENTIAL FOR GUSTY WINDS AT TIMES AND
POPS(ESPECIALLY BY LATER IN THE WEEK).
THE DRY UPPER RIDGING PATTERN OF SUNDAY WILL TRANSITION TO A DRY
ZONAL TO NORTHWESTERLY UPPER FLOW PATTERN FROM SUNDAY NIGHT INTO
AT LEAST WEDNESDAY EVENING.
THEN...AN UPPER SYSTEM APPROACHING THE FORECAST DISTRICT BY LATE
WEEK WILL BRING THE POTENTIAL FOR UNSETTLED METEOROLOGICAL
CONDITIONS BY LATER NEXT WEEK(ESPECIALLY OVER PORTIONS OF THE
CENTRAL AND WESTERN MOUNTAINS).
IN ADDITION...VARYING DEGREES OF EASTERN COLORADO SURFACE LEE-SIDE
TROUGHING IS ANTICIPATED FROM SUNDAY INTO FRIDAY WITH THE
POTENTIAL FOR A NORTHERLY SURGE MOVING ACROSS EASTERN SECTIONS
DURING FRIDAY EVENING/NIGHT.
THE HIGHEST POTENTIAL FOR STRONGER GRADIENT WINDS DURING THE
LONGER TERM SHOULD BE NOTED FROM THURSDAY INTO NEXT WEEKEND.
IN REGARDS TO TEMPERATURES...GENERALLY ABOVE SEASONAL EARLY TO
MID-DECEMBER TEMPERATURES ARE PROJECTED FROM SUNDAY INTO FRIDAY
WITH COOLER TEMPERATURES ANTICIPATED BY NEXT SATURDAY. AT THIS
TIME...IT APPEARS THAT THE WARMEST CONDITIONS DURING THE LONGER
TERM SHOULD BE REALIZED FROM MONDAY INTO WEDNESDAY...WITH COOLEST
READINGS EXPECTED BY FRIDAY AND ESPECIALLY NEXT SATURDAY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 458 AM MST SAT DEC 5 2015
VFR CONDITIONS ARE EXPECTED AT KALS AND KPUB TODAY. KPUB MAY SEE
SOME SHOWERS IN THE VCNTY THIS AFTERNOON BUT CHANCES ARE TOO LOW TO
INCLUDE IN THE TAF. KCOS WILL SEE CIGS LOWER AND THERE WILL BE THE
CHANCE FOR SOME PCPN IN THE AREA BY AROUND 18Z AND CONTINUING INTO
THE EARLY EVENING HOURS. IT IS POSSIBLE THAT PCPN AT KCOS COULD
CAUSE BRIEF MVFR CONDITIONS THIS AFTERNOON.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
820 AM CST SAT DEC 5 2015
.SHORT TERM...
312 AM CST
THROUGH SUNDAY NIGHT...
LOW STRATUS AND FOG THE PRIMARY FORECAST CONCERNS OVER THE NEXT
COUPLE DAYS. SURFACE HIGH PRESSURE IS CENTERED OVER THE UPPER OHIO
VALLEY EARLY THIS MORNING AND IS PROGGED TO BUILD TOWARDS THE
MID ATLANTIC COAST OVER THE WEEKEND. SATELLITE IMAGERY AND SURFACE
OBS SHOWS LOW STRATUS AND FOG BLANKETING THE EASTERN 2/3 OR SO OF
ILLINOIS AND PRACTICALLY ALL OF INDIANA. CLOUDS HAVE BEEN STEADILY
SPREADING NORTHWEST OVERNIGHT AND SHOULD BLANKET THE ENTIRE
FORECAST AREA THROUGH THE MORNING. THEREAFTER...THE ONLY MODEL
THAT WANTS TO HOLD ONTO THE CLOUD COVER THROUGH THE MAJORITY OF
THE DAY IS THE HRRR WHICH SEEMS FAIRLY REASONABLE GIVEN LACK OF
EROSION YESTERDAY. MOST OTHER MODELS BEGIN TO ERODE THE STRATUS BY
MIDDAY HOWEVER A RATHER IMPRESSIVE LOW LEVEL INVERSION COULD KEEP
THE LOW LEVEL MOISTURE TRAPPED THROUGH MUCH OF THE WEEKEND. 05Z
AMDAR SOUNDING OUT OF THE CHICAGO AREA SHOWED 980MB TEMP OF 0.3C
SHARPLY WARMING TO 9.0C AROUND 935MB. LATEST FORECAST GOES UNDER
THE ASSUMPTION THAT MOST OF THE CWA WILL REMAIN UNDER OVERCAST
SKIES AND HAVE ADJUSTED TEMPS DOWN QUITE A BIT FROM PREVIOUS
FORECASTS. FAR NORTH CENTRAL ILLINOIS WILL HAVE THE BEST CHANCE TO
SEE SOME EROSION ALONG THE EDGE OF THE STRATUS DECK BUT CONFIDENCE
IS LOW HOW THIS WILL PLAY OUT OR WHERE TO DRAW THE LINE. AS IS
TYPICAL WITH THESE SCENARIOS THERE IS LARGE BUST POTENTIAL...WITH
HIGHS ONLY IN THE UPPER 30S TO AROUND 40 ON THE COLD END UNDER
CLOUDS ALL DAY BUT IF SUNSHINE IS ABLE TO BREAK THROUGH...THOSE
VERY WARM TEMPS ALOFT WOULD SUPPORT TEMPERATURES QUICKLY SHOOTING
UP WITH HIGHS IN THE LOW 50S. OVERNIGHT...BOUNDARY LAYER FLOW
BACKS SLIGHTLY SO WOULD ANTICIPATE ANY LOW CIGS TO SPREAD BACK TO
ANY AREAS IN NORTH CENTRAL ILLINOIS THAT MIGHT ERODE ALONG THE
EDGE OF THE STRATUS...BUT CONFIDENCE IS FAIRLY LOW HOW THIS WILL
PLAY OUT.
SATURDAY NIGHT INTO SUNDAY...AN UPPER LEVEL WAVE WILL TRANSLATE
EAST ACROSS THE PLAINS REACHING THE OHIO VALLEY BY SUNDAY
EVENING. MID LEVEL HEIGHT FALLS IN ADVANCE OF THIS SYSTEM BEGIN TO
OVERSPREAD NORTHERN ILLINOIS SATURDAY NIGHT THOUGH THE BULK OF THE
FORCING STAYS SOUTH OF THE CWA DURING THE DAY SUNDAY. OUTSIDE OF
THE POSSIBLE CONTINUING LOW STRATUS...FAIRLY LITTLE MOISTURE IS
EXPECTED WITH THIS SYSTEM. MIGHT BE ABLE TO SQUEEZE OUT SOME
DRIZZLE SATURDAY NIGHT INTO EARLY SUNDAY BUT OTHERWISE CONFINED
POPS TO SOUTHWEST AREAS OF THE CWA AND ONLY SLIGHT CHC. LOW LEVEL
CLOUDS IF STILL AROUND EXPECTED TO FINALLY ERODE SUNDAY...HOWEVER
MID AND HIGH CLOUD COVER WILL BE INCREASING ACROSS THE AREA.
DEUBELBEISS
&&
.LONG TERM...
312 AM CST
MONDAY THROUGH FRIDAY...
UPPER PATTERN WILL BECOME ZONAL FOR THE UPCOMING WEEK WITH A
SERIES OF DISTURBANCES BRINGING PERIODIC CHANCES FOR PRECIP
PARTICULARLY THE LATTER HALF OF THE WEEK. TEMPERATURES SHOULD
REMAIN MILD THROUGH THE ENTIRE WEEK WITH A GRADUAL WARMING TREND
EXPECTED. TEMPERATURES ON MONDAY WILL MAX IN THE MID 40S ACROSS
THE FORECAST AREA AND LOW 50S ARE POSSIBLE BY THURSDAY AND FRIDAY.
BOTH THE ECMWF AND GFS ADVERTISE A SHORTWAVE TROUGH DROPPING
ACROSS UPPER MIDWEST/WESTERN GREAT LAKES WEDNESDAY NIGHT.
THEN...WILL HAVE TO KEEP A CLOSE EYE ON A POTENTIALLY MORE POTENT
SYSTEM LATE IN THE WEEK...THOUGH MODELS CONTINUE TO BOUNCE AROUND
ON THE DETAILS AS THEY STRUGGLE TO HANDLE THE PHASING OF UPPER
LEVEL ENERGY.
DEUBELBEISS
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 14Z...
* LIFR CIG/VIS IN STRATUS/FOG THROUGH AT LEAST MID
MORNING...BRIEF VLIFR VIS POSSIBLE EARLY.
* IMPROVEMENT TO IFR LIKELY BY MIDDAY...POSSIBLE CLEARING TO VFR
THIS AFTERNOON.
* POTENTIAL FOR REDEVELOPMENT OR LOWERING OF IFR/LIFR STRATUS/FOG
AGAIN TONIGHT.
RATZER/BEACHLER
//DISCUSSION...UPDATED 12Z...
STRATUS/FOG WHICH SPREAD ACROSS TERMINALS OVERNIGHT WILL REMAIN
THIS MORNING...WITH LIFR/VLIFR CONDITIONS GRADUALLY IMPROVING TO
IFR MID/LATE MORNING. WOULD EXPECT SOME EROSION AROUND THE EDGES
OF THE STRATUS DECK FROM MID-MORNING ON...THOUGH DEGREE OF
CLEARING LIKELY TO BE LIMITED THE FARTHER SOUTHEAST ONE GOES. IT
IS POSSIBLE SOME CLEARING EVEN TO VFR WILL OCCUR BY EARLY
AFTERNOON...MOST LIKELY AT RFD NEAR THE EDGE OF THE CLOUD DECK.
EVEN IF CIGS LINGER...WILL LIKELY SEE A DIURNAL RISE TO CIGS AND A
SIGNIFICANT IMPROVEMENT IN VIS. TOUGH QUESTION IS WHAT OCCURS
TONIGHT...AS CLEARING WOULD LIKELY SET THE STAGE FOR SOME
NORTHWARD REDEVELOPMENT SIMILAR TO LAST NIGHT...AND IF A CEILING
LINGERS LIKELY A DIURNAL LOWERING OF VIS/CIG. THUS WHILE GENERAL
TREND OF FORECAST IS FAIRLY GOOD CONFIDENCE...SPECIFIC DETAILS IN
TIMING AND EXACT CIG HEIGHTS/VIS REMAIN RATHER LOW.
WINDS WILL REMAIN GENERALLY SOUTHERLY...BETWEEN ABOUT 200-170 DEG
AND 10 KTS OR LESS.
RATZER
//ORD AND MDW CONFIDENCE...UPDATED 14Z...
* HIGH IN CURRENT LIFR/VLIFR CIG/VIS CONDITIONS AND IN IMPROVEMENT
TO IFR THROUGH MID/LATE MORNING. LOW IN EXACTLY HOW LOW VSBY
DROPS...BUT HIGH IN FALLING TO AT LEAST 1SM.
* LOW IN TIMING IMPROVEMENT TODAY...AND TRENDS TONIGHT.
RATZER/BEACHLER
//OUTLOOK FOR ORD/MDW FOR 00Z MONDAY-12Z SATURDAY...UPDATED 12Z...
SUNDAY NIGHT THROUGH TUESDAY...PRIMARILY VFR. SMALL DAY TO DAY
CHANCE OF IFR CIGS/FOG DURING LATE NIGHTS/MORNINGS.
WEDNESDAY...SLIGHT CHANCE -RA/MVFR.
THURSDAY...VFR/MVFR CIGS.
FRIDAY...SLIGHT CHANCE -RA AND MVFR/IFR.
RATZER
&&
.MARINE...
250 AM CST
HIGH PRESSURE MOVING EAST ACROSS THE UPPER OHIO VALLEY TO THE MID
ATLANTIC REGION TODAY...AND LOW PRESSURE MOVING FROM MANITOBA TO
HUDSON BAY...WILL ALLOW SOUTH-SOUTHWEST WINDS TO PERSIST ACROSS
LAKE MICHIGAN. THE GRADIENT WILL TIGHTEN DURING THE DAY IN
RESPONSE TO PRESSURE FALLS ASSOCIATED WITH THE CANADIAN LOW...
WITH SOUTHERLY WINDS INCREASING INTO THE 30 KT RANGE THIS
AFTERNOON INTO TONIGHT OVER THE NORTHERN PART OF THE LAKE. THE
GRADIENT WILL THEN WEAKEN SUNDAY AS A WEAK COLD FRONT SLIDES
SOUTHEAST ACROSS THE LAKE...WITH WINDS SHIFTING TO THE WEST-
NORTHWEST. WEAK HIGH PRESSURE WILL BUILD IN BEHIND THE FRONT
SUNDAY NIGHT INTO MONDAY...BEFORE THE PATTERN REVERTS TO LOW
PRESSURE LIFTING NORTHEAST ACROSS CANADA AND NORTH OF THE LAKES
AND BRINGS A RETURN TO SOUTH-SOUTHWEST WINDS INTO EARLY NEXT WEEK.
RATZER
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...DENSE FOG ADVISORY...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-ILZ010-
ILZ011-ILZ012-ILZ013-ILZ014-ILZ019-ILZ020-ILZ021-ILZ022-
ILZ023-ILZ032-ILZ033-ILZ039 UNTIL NOON SATURDAY.
IN...DENSE FOG ADVISORY...INZ001-INZ002-INZ010-INZ011-INZ019 UNTIL
NOON SATURDAY.
LM...NONE.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
558 AM CST SAT DEC 5 2015
.SHORT TERM...
312 AM CST
THROUGH SUNDAY NIGHT...
LOW STRATUS AND FOG THE PRIMARY FORECAST CONCERNS OVER THE NEXT
COUPLE DAYS. SURFACE HIGH PRESSURE IS CENTERED OVER THE UPPER OHIO
VALLEY EARLY THIS MORNING AND IS PROGGED TO BUILD TOWARDS THE
MID ATLANTIC COAST OVER THE WEEKEND. SATELLITE IMAGERY AND SURFACE
OBS SHOWS LOW STRATUS AND FOG BLANKETING THE EASTERN 2/3 OR SO OF
ILLINOIS AND PRACTICALLY ALL OF INDIANA. CLOUDS HAVE BEEN STEADILY
SPREADING NORTHWEST OVERNIGHT AND SHOULD BLANKET THE ENTIRE
FORECAST AREA THROUGH THE MORNING. THEREAFTER...THE ONLY MODEL
THAT WANTS TO HOLD ONTO THE CLOUD COVER THROUGH THE MAJORITY OF
THE DAY IS THE HRRR WHICH SEEMS FAIRLY REASONABLE GIVEN LACK OF
EROSION YESTERDAY. MOST OTHER MODELS BEGIN TO ERODE THE STRATUS BY
MIDDAY HOWEVER A RATHER IMPRESSIVE LOW LEVEL INVERSION COULD KEEP
THE LOW LEVEL MOISTURE TRAPPED THROUGH MUCH OF THE WEEKEND. 05Z
AMDAR SOUNDING OUT OF THE CHICAGO AREA SHOWED 980MB TEMP OF 0.3C
SHARPLY WARMING TO 9.0C AROUND 935MB. LATEST FORECAST GOES UNDER
THE ASSUMPTION THAT MOST OF THE CWA WILL REMAIN UNDER OVERCAST
SKIES AND HAVE ADJUSTED TEMPS DOWN QUITE A BIT FROM PREVIOUS
FORECASTS. FAR NORTH CENTRAL ILLINOIS WILL HAVE THE BEST CHANCE TO
SEE SOME EROSION ALONG THE EDGE OF THE STRATUS DECK BUT CONFIDENCE
IS LOW HOW THIS WILL PLAY OUT OR WHERE TO DRAW THE LINE. AS IS
TYPICAL WITH THESE SCENARIOS THERE IS LARGE BUST POTENTIAL...WITH
HIGHS ONLY IN THE UPPER 30S TO AROUND 40 ON THE COLD END UNDER
CLOUDS ALL DAY BUT IF SUNSHINE IS ABLE TO BREAK THROUGH...THOSE
VERY WARM TEMPS ALOFT WOULD SUPPORT TEMPERATURES QUICKLY SHOOTING
UP WITH HIGHS IN THE LOW 50S. OVERNIGHT...BOUNDARY LAYER FLOW
BACKS SLIGHTLY SO WOULD ANTICIPATE ANY LOW CIGS TO SPREAD BACK TO
ANY AREAS IN NORTH CENTRAL ILLINOIS THAT MIGHT ERODE ALONG THE
EDGE OF THE STRATUS...BUT CONFIDENCE IS FAIRLY LOW HOW THIS WILL
PLAY OUT.
SATURDAY NIGHT INTO SUNDAY...AN UPPER LEVEL WAVE WILL TRANSLATE
EAST ACROSS THE PLAINS REACHING THE OHIO VALLEY BY SUNDAY
EVENING. MID LEVEL HEIGHT FALLS IN ADVANCE OF THIS SYSTEM BEGIN TO
OVERSPREAD NORTHERN ILLINOIS SATURDAY NIGHT THOUGH THE BULK OF THE
FORCING STAYS SOUTH OF THE CWA DURING THE DAY SUNDAY. OUTSIDE OF
THE POSSIBLE CONTINUING LOW STRATUS...FAIRLY LITTLE MOISTURE IS
EXPECTED WITH THIS SYSTEM. MIGHT BE ABLE TO SQUEEZE OUT SOME
DRIZZLE SATURDAY NIGHT INTO EARLY SUNDAY BUT OTHERWISE CONFINED
POPS TO SOUTHWEST AREAS OF THE CWA AND ONLY SLIGHT CHC. LOW LEVEL
CLOUDS IF STILL AROUND EXPECTED TO FINALLY ERODE SUNDAY...HOWEVER
MID AND HIGH CLOUD COVER WILL BE INCREASING ACROSS THE AREA.
DEUBELBEISS
&&
.LONG TERM...
312 AM CST
MONDAY THROUGH FRIDAY...
UPPER PATTERN WILL BECOME ZONAL FOR THE UPCOMING WEEK WITH A
SERIES OF DISTURBANCES BRINGING PERIODIC CHANCES FOR PRECIP
PARTICULARLY THE LATTER HALF OF THE WEEK. TEMPERATURES SHOULD
REMAIN MILD THROUGH THE ENTIRE WEEK WITH A GRADUAL WARMING TREND
EXPECTED. TEMPERATURES ON MONDAY WILL MAX IN THE MID 40S ACROSS
THE FORECAST AREA AND LOW 50S ARE POSSIBLE BY THURSDAY AND FRIDAY.
BOTH THE ECMWF AND GFS ADVERTISE A SHORTWAVE TROUGH DROPPING
ACROSS UPPER MIDWEST/WESTERN GREAT LAKES WEDNESDAY NIGHT.
THEN...WILL HAVE TO KEEP A CLOSE EYE ON A POTENTIALLY MORE POTENT
SYSTEM LATE IN THE WEEK...THOUGH MODELS CONTINUE TO BOUNCE AROUND
ON THE DETAILS AS THEY STRUGGLE TO HANDLE THE PHASING OF UPPER
LEVEL ENERGY.
DEUBELBEISS
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 12Z...
* LIFR CIG/VIS IN STRATUS/FOG THROUGH AT LEAST MID
MORNING...BRIEF VLIFR VIS POSSIBLE EARLY.
* IMPROVEMENT TO IFR LIKELY BY MIDDAY...POSSIBLE CLEARING TO VFR
THIS AFTERNOON.
* POTENTIAL FOR REDEVELOPMENT OR LOWERING OF IFR/LIFR STRATUS/FOG
AGAIN TONIGHT.
RATZER
//DISCUSSION...UPDATED 12Z...
STRATUS/FOG WHICH SPREAD ACROSS TERMINALS OVERNIGHT WILL REMAIN
THIS MORNING...WITH LIFR/VLIFR CONDITIONS GRADUALLY IMPROVING TO
IFR MID/LATE MORNING. WOULD EXPECT SOME EROSION AROUND THE EDGES
OF THE STRATUS DECK FROM MID-MORNING ON...THOUGH DEGREE OF
CLEARING LIKELY TO BE LIMITED THE FARTHER SOUTHEAST ONE GOES. IT
IS POSSIBLE SOME CLEARING EVEN TO VFR WILL OCCUR BY EARLY
AFTERNOON...MOST LIKELY AT RFD NEAR THE EDGE OF THE CLOUD DECK.
EVEN IF CIGS LINGER...WILL LIKELY SEE A DIURNAL RISE TO CIGS AND A
SIGNIFICANT IMPROVEMENT IN VIS. TOUGH QUESTION IS WHAT OCCURS
TONIGHT...AS CLEARING WOULD LIKELY SET THE STAGE FOR SOME
NORTHWARD REDEVELOPMENT SIMILAR TO LAST NIGHT...AND IF A CEILING
LINGERS LIKELY A DIURNAL LOWERING OF VIS/CIG. THUS WHILE GENERAL
TREND OF FORECAST IS FAIRLY GOOD CONFIDENCE...SPECIFIC DETAILS IN
TIMING AND EXACT CIG HEIGHTS/VIS REMAIN RATHER LOW.
WINDS WILL REMAIN GENERALLY SOUTHERLY...BETWEEN ABOUT 200-170 DEG
AND 10 KTS OR LESS.
RATZER
//ORD AND MDW CONFIDENCE...UPDATED 12Z...
* HIGH IN CURRENT LIFR/VLIFR CIG/VIS CONDITIONS AND IN IMPROVEMENT
TO IFR THROUGH MID/LATE MORNING. LOW IN EXACTLY HOW LOW VSBY
DROPS...BUT HIGH IN FALLING TO AT LEAST 1SM.
* LOW IN TIMING IMPROVEMENT TODAY...AND TRENDS TONIGHT.
RATZER
//OUTLOOK FOR ORD/MDW FOR 00Z MONDAY-12Z SATURDAY...UPDATED 12Z...
SUNDAY NIGHT THROUGH TUESDAY...PRIMARILY VFR. SMALL DAY TO DAY
CHANCE OF IFR CIGS/FOG DURING LATE NIGHTS/MORNINGS.
WEDNESDAY...SLIGHT CHANCE -RA/MVFR.
THURSDAY...VFR/MVFR CIGS.
FRIDAY...SLIGHT CHANCE -RA AND MVFR/IFR.
RATZER
&&
.MARINE...
250 AM CST
HIGH PRESSURE MOVING EAST ACROSS THE UPPER OHIO VALLEY TO THE MID
ATLANTIC REGION TODAY...AND LOW PRESSURE MOVING FROM MANITOBA TO
HUDSON BAY...WILL ALLOW SOUTH-SOUTHWEST WINDS TO PERSIST ACROSS
LAKE MICHIGAN. THE GRADIENT WILL TIGHTEN DURING THE DAY IN
RESPONSE TO PRESSURE FALLS ASSOCIATED WITH THE CANADIAN LOW...
WITH SOUTHERLY WINDS INCREASING INTO THE 30 KT RANGE THIS
AFTERNOON INTO TONIGHT OVER THE NORTHERN PART OF THE LAKE. THE
GRADIENT WILL THEN WEAKEN SUNDAY AS A WEAK COLD FRONT SLIDES
SOUTHEAST ACROSS THE LAKE...WITH WINDS SHIFTING TO THE WEST-
NORTHWEST. WEAK HIGH PRESSURE WILL BUILD IN BEHIND THE FRONT
SUNDAY NIGHT INTO MONDAY...BEFORE THE PATTERN REVERTS TO LOW
PRESSURE LIFTING NORTHEAST ACROSS CANADA AND NORTH OF THE LAKES
AND BRINGS A RETURN TO SOUTH-SOUTHWEST WINDS INTO EARLY NEXT WEEK.
RATZER
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...DENSE FOG ADVISORY...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-ILZ010-
ILZ011-ILZ012-ILZ013-ILZ014-ILZ019-ILZ020-ILZ021-ILZ022-
ILZ023-ILZ032-ILZ033-ILZ039 UNTIL NOON SATURDAY.
IN...DENSE FOG ADVISORY...INZ001-INZ002-INZ010-INZ011-INZ019 UNTIL
NOON SATURDAY.
LM...NONE.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
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WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
National Weather Service Lincoln IL
508 AM CST SAT DEC 5 2015
.SHORT TERM...(Today)
ISSUED AT 243 AM CST SAT DEC 5 2015
Dense fog continues to expand north and west early this morning as
the boundary layer flow remains out of the east and southeast. Have
expanded the Dense Fog advisory to include all counties except
Schuyler until Noon. Latest few runs of the HRRR suggest the fog
will edge west to Schuyler county just after 12z and then begin to
dissipate after sunrise. High pressure centered over Ohio will inch
slowly away from the area with the ridge axis forecast to extend
west into our area through much of the day. Forecast soundings
showing a very shallow moist layer at the surface trapped underneath
a strong low level inversion thru the day with our west and
southwest counties seeing the sun first with our eastern counties
not seeing any significant breaks until this afternoon, if then.
For what is usually a recipe for a big temperature bust, will use
continuity with respect to forecast highs this afternoon with a
very similar setup to what we experienced yesterday. Based off
that reasoning, will go fairly close to the highs obtained
yesterday afternoon, especially across the east where readings in
some areas didn`t get out of the 30s. Don`t have anything quite
that cool today as RUC soundings even in our far east were showing
several hours where we could see a little sunshine, unlike the
latest HRRR run which was showing the stratus and low visibilities
holding across our east throughout the afternoon. Our warmest
readings once again will be in the west where the mercury should
top out in the lower 50s, while roughly along and east of the I-55
corridor, afternoon highs will be mostly in the 40s, with a few
locations over east central IL just getting to 40 degree later
this afternoon.
.LONG TERM...(Tonight through Friday)
ISSUED AT 243 AM CST SAT DEC 5 2015
Low level inversion does not appear to be going away until Sunday,
when a shortwave currently located over Idaho and Utah arrives. SREF
probability guidance indicates the fog is likely to expand westward
once again this evening and cover most areas north of I-70. Would
not be surprised if another fog advisory is needed, but will wait to
see how much conditions can improve this afternoon first.
Aforementioned upper wave will close off as it crosses Illinois
Sunday afternoon. Have increased PoP`s to about 30% west of a Peoria
to Springfield line, mostly on the back side of the low, and
introduced 30% PoP`s across the southeast quarter of the forecast
area for evening as the low shifts into Indiana.
Remainder of the forecast period will be fairly mild for this time
of year, as the general upper flow remains of Pacific origin. Some
questions exist for late week, as one upper wave in particular digs
as it crosses the Dakotas. The ECMWF is more aggressive with this
digging and draws some colder air aloft southward from Manitoba,
producing a slower and more robust surface low/front Thursday night.
The GFS is much weaker and basically has a dry frontal passage.
Leaned a bit more toward the slower solution for now, but did not
make any significant changes to the initialized forecast grids due
to the uncertainty.
&&
.AVIATION...(For the 12Z TAFS through 12Z Sunday morning)
ISSUED AT 505 AM CST SAT DEC 5 2015
IFR TO VLIFR conditions are expected thru the morning hours before
a gradual improvement this afternoon, especially across our
western TAF sites. We have seen a temporary improvement in cigs
and vsbys at BMI and SPI but based on satellite and surface obs
to our east and south, it looks as if the cigs and vsbys will
come down again at both sites in the next hour or two. Forecast
soundings not offering much hope for any significant break in the
cigs late this morning into this afternoon with PIA and SPI seeing
the best chance for cigs to break for a time. Little change in the
air mass is expected as we head into the overnight hours with
the threat for fog and low cigs to redevelop again and hold into
the morning hours of Sunday. Surface winds will remain a non-
factor thru tonight with a south to southeast wind at 7 to
12 kts today, and from 5 to 10 kts tonight.
&&
.ILX Watches/Warnings/Advisories...
Dense Fog Advisory until noon CST today for ILZ027>031-036>038-
041>057-061>063-066>068-071>073.
&&
$$
SHORT TERM...Smith
LONG TERM...Geelhart
AVIATION...Smith
AREA FORECAST DISCUSSION...UPDATED
NWS QUAD CITIES IA IL
515 AM CST SAT DEC 5 2015
.UPDATE...
ISSUED AT 441 AM CST SAT DEC 5 2015
THE FOG HAS FILLED IN AND THE EDGE IS NOW ALONG A LINE FROM
GENESEO TO MOUNT CARROLL TO FREEPORT AND CONTINUING TO EXPAND
WEST. IT BEGAN TO SHOW A MORE DISTINCTIVE PUSH TO THE WEST OVER
THE PAST FEW HOURS...ESPECIALLY OVER THE NORTHERN PART OF THE
AREA. THEREFORE...DID EXPAND THE ADVISORY A TIER OF COUNTIES TO
THE WEST. THE FOG IS NOW CLOSE TO WHERE THE HRRR MODEL HAS BEEN
INDICATING IT WOULD REACH SO NOT ANTICIPATING THE NEED TO EXPAND
ANY FURTHER WEST AT THIS TIME. ALSO...THERE IS A DIMINISHING TREND
IN THE FOG ALONG AND EAST OF HIGHWAY 40 AND INTERSTATE 155 FROM
BRADFORD TO SOUTH OF PEORIA AND IF THIS CONTINUES TO ERODE THE FOG
FROM THE MIDDLE OUT...THE ADVISORY WOULD LIKELY BE NEEDED TO BE
CANCELLED EARLY. HOWEVER MODELS ARE STILL STUCK ON THE IDEA OF THE
FOG STICKING AROUND UNTIL EARLY AFTERNOON IN ALL AREAS. BELIEVE
THE MODELS CONTINUE TO BE OVERDONE AND FOG WILL BE ERODED BY LATE
THIS MORNING.
&&
.SYNOPSIS...
ISSUED AT 345 AM CST SAT DEC 5 2015
AT 09Z WATER VAPOR IMAGERY SHOWED BROAD RIDGING OVER
THE EASTERN PART OF THE CONUS WHICH EXTENDED THROUGH ONTARIO. A WEAK
SHORTWAVE WAS NOTED FROM THE EASTERN DAKOTAS THROUGH THE MID
MISSISSIPPI RIVER VALLEY WITH A BROAD LONGWAVE TROUGH IN PLACE
ACROSS THE WESTERN HALF OF THE CONUS. AT THE SURFACE...HIGH PRESSURE
WAS IN PLACE OVER OHIO WITH WEAK ANTI-CYCLONIC FLOW PUSHING ACROSS
ILLINOIS. A TROUGH OF LOW PRESSURE WAS IN PLACE ACROSS THE HIGH
PLAINS...LEADING TO AN INCREASING PRESSURE GRADIENT GOING WEST FROM
ILLINOIS THROUGH THE PLAINS. THIS LED TO A CHANGE IN LOW LEVEL FLOW
FROM THE SOUTHWEST...AND LESSER INFLUENCE FROM THE EASTERN AIRMASS.
FOG WAS ABUNDANT IN AREAS UNDER THE INFLUENCE OF THE SURFACE HIGH
WITH DENSE FOG BEING OBSERVED ACROSS MUCH OF ILLINOIS.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 345 AM CST SAT DEC 5 2015
PRIMARY CONCERNS WITH THIS FORECAST CYCLE IS WITH FOG THIS MORNING
AND TEMPERATURES TODAY. THEN AGAIN WITH FOG POTENTIAL AGAIN TONIGHT.
THE FOG CONTINUES TO EXPAND WESTWARD BUT THE LEADING EDGE DOESN/T
SEEM TO BE MAKING MUCH MORE PROGRESS WEST OVER THE PAST HOUR AND
HAS MAINLY BEEN FILLING IN. SO...MAY BE CLOSE TO WHERE IT WILL END
UP...MAINLY EAST OF A LINE FROM MACOMB TO GENESEO TO FREEPORT. THE
MORE WIDESPREAD FOG REMAINS OVER BUREAU AND PUTNAM
COUNTIES...ALTHOUGH HAS EDGED INTO WHITESIDE AND HENRY COUNTIES.
AT THIS POINT...WILL FOREGO EXPANDING THE ADVISORY AS THE FOG IS
NOT QUITE AS WIDESPREAD BUT WILL CONTINUE TO WATCH ITS BEHAVIOR
THROUGH THE MORNING. AS FOR TIMING OF THE FOG LIFTING. WITH THE
TIME OF YEAR AND NOT MUCH FOR LOW LEVEL FLOW THIS MORNING...NOT
EXPECTING A FAST CLEARING OF THE FOG AND WILL LIKELY CONTINUE INTO
MID OR EVEN LATE MORNING...BUT WITH THE LOCAL AREA ON THE
EDGE...WILL LIKELY SEE THE FOG LIFTED EARLIER THAN AREAS TO THE
EAST.
TEMPERATURES OVER THE EASTERN PART OF THE FORECAST AREA WILL BE
HEAVILY INFLUENCED BY THE FOG THE LONGER IT PERSISTS. DID GO A BIT
COOLER FOR HIGHS WHERE FOG/CLOUDS WILL BE IN PLACE THROUGH THE
MORNING...DELAYING THE WARMING. ELSEWHERE...SHOULD SEE A GOOD WARM-
UP FOR THIS TIME OF YEAR AS DECENT MIXING SHOULD OCCUR TO AROUND
950MB WHICH WOULD BRING TEMPERATURES INTO THE UPPER 40S AND LOW 50S.
THEN FOR TONIGHT...AS THE TROUGH OF LOW PRESSURE APPROACHES FROM THE
WEST...SO WILL CLOUDS. BUT MOST MODELS INDICATE MANY WILL STAY WEST
OF THE FORECAST ARE THROUGH MUCH OF THE NIGHT. THERE ARE INDICATIONS
THOUGH THAT FOG WILL REDEVELOP ACROSS ILLINOIS DURING THE EVENING
AND THEN EXPAND WEST OVERNIGHT AND BACK INTO THE EASTERN PART OF THE
FORECAST AREA. DON/T HAVE HIGH CONFIDENCE ON ANYTHING DENSE...BUT
DID INCLUDE FOG MENTION IN THE FORECAST FOR THESE AREAS TONIGHT.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 345 AM CST SAT DEC 5 2015
A CLOSED UPPER LOW CONTINUES TO BE FORECAST BY ALL MODELS TO
PROGRESS THROUGH IOWA AND ILLINOIS DURING THE DAY SUNDAY INTO EARLY
SUNDAY EVENING. AS HAS BEEN THE CASE IN THE PAST FEW DAYS OF MODEL
DATA...IT APPEARS THIS SYSTEM WILL HAVE ACCESS TO LITTLE IF ANY
MOISTURE FROM THE SOUTH. THE SMALL AMOUNT OF MOISTURE DRAWN FROM
ITS PACIFIC ORIGINS WILL LIKELY WRING OUT IN LIGHT RAIN...WITH QPF
AMOUNTS UNDER 1 TENTH OF AN INCH. WE WILL CONTINUE WITH FAIRLY LOW
POPS FOR WHAT COULD END UP BEING A HIGH POP LOW QPF EVENT IF
SATURATION CAN BE ACHIEVED OVER A LARGER PORTION OF THE CWA. UNDER
THE HIGH CONFIDENCE CLOUDY SKIES...SUNDAY AFTERNOON TEMPERATURES
SHOULD BE HELD TO THE LOWER 40S IN MOST LOCATIONS...AND UNDER
SIMILARLY MOSTLY CLOUDY SKIES SUNDAY NIGHT...LOWS SHOULD ONLY FALL
TO THE THE LOWER 30S. IT BEARS WATCHING LATE SUNDAY NIGHT AS THE MID
CLOUDS MOVE OFF TO THE EAST...SOME SHALLOW FOG DEVELOPMENT APPEARS
POSSIBLE...AND THAT COULD BE DENSE IF WIDESPREAD LIGHT RAIN DOES
OCCUR SUNDAY.
WEAK HIGH PRESSURE WILL MOVE OVER THE AREAS MONDAY MORNING...WITH
RETURN FLOW QUICKLY DEVELOPING FOR MONDAY NIGHT AND TUESDAY. HIGHS
MONDAY AND TUESDAY SHOULD ONCE AGAIN REACH THE MID 40S TO NEAR 50.
ANOTHER WEAK UPPER LOW SHOULD BRUSH THE REGION TUESDAY AFTERNOON AND
NIGHT...WITH LOW POPS NORTH FOR LIGHT RAIN. FOLLOWING THAT...A MORE
SIGNIFICANT DEEP PROGRESSIVE UPPER TROF WILL SWEEP THROUGH THE
MIDWEST BY LATE IN THE WORK WEEK. AHEAD OF THIS FRONT/TROF
PASSAGE...AT LEAST TWO DAYS OF SUSTAINED WAA WILL TAKE PLACE. THIS
WILL EVENTUALLY DRAW UP SOME DEEPER MOISTURE THAN WE WILL HAVE SEEN
IN OVER WEEK...AND WITH THAT...A CHANCE FOR SEASONALLY SIGNIFICANT
RAINFALL IS GROWING FOR THE THURSDAY AND FRIDAY TIME PERIOD. THE
ATMOSPHERE WOULD CERTAINLY BE MILD ENOUGH FOR ALL RAIN DURING THOSE
TWO DAYS. HIGHS WOULD EASILY REACH THE MID 40S TO AROUND 50 IN THE
MOIST AIRMASS...WITH LOWS IN THE MID 30S TO MID 40S.
ERVIN
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1123 PM CST FRI DEC 4 2015
AREA OF LOW CLOUDS AND FOG EXPANDING NORTHWARD INTO CENTRAL AND
NORTHERN ILLINOIS THIS EVENING WILL LIKELY REMAIN EAST OF THE
TERMINALS THROUGH TONIGHT. VISIBILITIES WERE BEGINNING TO DROP
SOME WELL WEST OF THE STRATUS...AND IT IS LOOKING LIKELY THAT AT
LEAST MVFR FOG WILL DEVELOP AT ALL SITES...WHICH HAS BEEN ADDED IN
THE LATEST FORECASTS FOR LATE TONIGHT THROUGH MID MORNING
SATURDAY. THERE IS A CONTINUED LOW POTENTIAL THAT THE IFR
CONDITIONS COULD SEEP INTO THE BRL AND MLI TERMINALS TOWARD
SUNRISE. VFR CONDITIONS ARE LIKELY FOR SATURDAY AFTERNOON THROUGH
EVENING WITH LIGHT SOUTHERLY WINDS.
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...DENSE FOG ADVISORY UNTIL NOON CST TODAY FOR BUREAU-CARROLL-HENRY
IL-PUTNAM-STEPHENSON-WHITESIDE.
MO...NONE.
&&
$$
UPDATE...BROOKS
SYNOPSIS...ERVIN
SHORT TERM...ERVIN
LONG TERM...BROOKS
AVIATION...SHEETS
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
947 AM EST SAT DEC 5 2015
LATEST UPDATE...
UPDATE
.SYNOPSIS...
ISSUED AT 320 AM EST SAT DEC 5 2015
HIGH PRESSURE WILL PRODUCE FAIR AND MILD WEATHER THROUGH THE
WEEKEND. HOWEVER AREAS OF DENSE FOG THIS MORNING WILL CAUSE
HAZARDOUS TRAVEL CONDITIONS. TEMPERATURES WILL CONTINUE TO AVERAGE
AT LEAST TEN TO FIFTEEN DEGREES ABOVE NORMAL THROUGH THE UPCOMING
WEEK.
&&
.UPDATE...
ISSUED AT 946 AM EST SAT DEC 5 2015
EXTENDING THE DENSE FOG ADVISORY ACROSS THE SOUTHERN THREE ROWS OF
COUNTIES UNTIL 100 PM...OR ROUGHLY FROM GRAND HAVEN TO GRAND
RAPIDS TO ST. JOHNS SOUTHWARD. WILL BE CANCELLING THE DENSE FOG
ADVISORY ACROSS THE NORTHERN THREE TIERS OF COUNTIES...OR ACROSS
CENTRAL LOWER MI.
DENSE FOG IS STILL WIDESPREAD ACROSS THE SOUTH...WITH MANY SITES
REPORTING A QUARTER MILE VISIBILITY. NOT CONVINCED IT IS GOING TO
RAPIDLY ERODE IN THE NEXT HOUR OR SO...SO FELT IT WAS NECESSARY TO
EXTEND IT THROUGH 100 PM. ONCE THE FOG ERODES AND VISIBILITY
IMPROVES WE WILL CANCEL THE ADVISORY WHICH SHOULD BE SOME TIME
BETWEEN 1100 AM AND 100 PM.
&&
.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 320 AM EST SAT DEC 5 2015
A FREEZING FOG ADVISORY REMAINS IN EFFECT FOR ALL OF OUR FCST AREA
THROUGH 15Z THIS MORNING. SFC OBS/GROUND TRUTH REPORTS CONTINUE TO
INDICATE AREAS OF DENSE FOG ACROSS MUCH OF OUR FCST AREA. THIS IN
CONJUNCTION WITH SFC TEMPS AT OR BELOW FREEZING ACROSS PORTIONS OF
OUR AREA WILL RESULT IN HAZARDOUS TRAVEL CONDITIONS THROUGH MID
MORNING.
FOG WILL GRADUALLY DISSIPATE LATE THIS MORNING AND SKIES ARE
EXPECTED TO BECOME PARTLY TO MOSTLY SUNNY THIS AFTERNOON WITH
SUBSIDENCE UNDER THE HIGH PRESSURE RIDGE. IT WILL BECOME MILD AGAIN
TODAY WITH HIGH TEMPS REACHING THE MIDDLE TO UPPER 40S (00Z MET
NUMERICAL GUIDANCE MAXES ARE MUCH TOO COOL). THE HIGH PRESSURE RIDGE
WILL CONTINUE IN CONTROL OF THE WX PATTERN AND BRING FAIR WEATHER
THROUGH MONDAY.
.LONG TERM...(MONDAY NIGHT THROUGH FRIDAY)
ISSUED AT 320 AM EST SAT DEC 5 2015
THE SHORT STORY IS WARMER THAN NORMAL TEMPERATURES WILL BE FOLLOWED
MUCH WARMER THAN NORMAL TEMPERATURES LATER IN THE WEEK. WE WILL
TREND INTO A MUCH WETTER PATTERN AS WE HEAD TOWARD NEXT WEEKEND.
FOR THE MOST PART THE MODELS HAVE BEEN VERY CONSISTENT IN THE LARGE
SCALE DETAIL FOR THIS COMING WEEK. OUR VERY ACTIVE PACIFIC WAVE
TRAIN CONTINUES TO FEED SYSTEMS ON SHORE ABOUT EVERY TWO DAYS. WITH
THE SPLIT FLOW MOST OF THE PRECIPITATION HAS BEEN WELL NORTH IN
CANADA AND THIS COMING WEEK WE WILL SEE A LITTLE RAIN TRACK JUST
SOUTH OF MICHIGAN WITH THE SOUTHERN STREAM EARLY IN THE WEEK.
HOWEVER AS OUR VERY IMPRESSIVE 180 KNOT EAST ASIAN JET CORE (WE
HAVE BEEN FOLLOWING THIS ALL WEEK) GETS CLOSER TO WESTERN NORTH
AMERICA THE WAVES MOVING ON SHORE WILL AMPLIFY. THIS WILL
INCREASE THE FLOW OF GULF MOISTURE NORTH AND ALSO INCREASE JUST
HOW FAR NORTH THAT MOISTURE GETS.
IT SEEMS TO ME THE STORM NOW OFF THE WEST COAST (LOOKS GREAT ON THE
1 AM WATER VAPOR LOOPS...CHECK IT OUT OF YOU CAN) WILL BE OUR
WEDNESDAY SYSTEM. THIS ONE MAY HAVE ENOUGH WAVE LENGTH AS IT MOVES
TROUGH THE CENTRAL PLAINS TO GIVE US A FEW SHOWERS WEDNESDAY.
THERE WILL BE ONE MORE SYSTEM COMING THROUGH BEFORE THE SYSTEM WITH
THAT EAST ASIAN JET CORE OVER 180 KNOTS MOVES ONSHORE. THAT ONE
REACHES US IN THE FRIDAY TIME FRAME. THAT WILL BE MORE AMPLIFIED THAN
THE WEDNESDAY SYSTEM SO EXPECT A MORE WIDESPREAD RAIN EVENT WITH
THAT ONE.
MORE THAN LIKELY OUR TEMPERATURE FORECAST IS TO CONSERVATIVE... I
BELIEVE WE COULD SEE ACTUAL TEMPERATURE AS MUCH AS 5 TO 10 DEGREES
WARMER THAN WE ARE FORECASTING BY LATE IN THE PERIOD.
.WEEK TWO FORECAST...(SATURDAY THROUGH FRIDAY)
OF COURSE THE MAIN SHOW COMES THE NEXT WEEKEND INTO THE MIDDLE OF
THE FOLLOWING WEEK. BOTH THE ECMWF AND GFS SHOW THE AO AND NAO TENDING
TOWARD NEGATIVE VALUES THEN AND THE PNA GOING POSITIVE. ALL THAT
WOULD SUGGEST WESTERN RIDGE AND EASTERN TROUGH. THIS GOES WELL
WITH THE PROGRESSION OF THAT EAST ASIAN JET CORE. THE MAIN ENERGY
FOR THIS SYSTEM WILL COME TROUGH THE GREAT LAKES DURING THE
WEEKEND OF THE 12TH (SATURDAY). TIMING MAY BE SLOWER THAN I AM
SAYING BUT THE SYSTEM IN THE TIME FRAME OF SUNDAY THE 13TH COULD
BE A VERY DEEP SURFACE LOW WITH A LOT OF WIND AND A STRONG SURGE
OF EVERY WARM AIR. IT IS THIS SYSTEM THAT I THINK WILL BEING US
RECORD OR NEAR RECORD HIGHS IN THE MID 60S SATURDAY OR SUNDAY.
FOR THOSE WAITING FOR SNOW AND COLD... YOU MAY GET YOUR WISH BY THE
MIDDLE TO END OF THAT WEEK (THINK THE 15TH TO 18TH). THERE IS ONE
MORE SHORTWAVE THAT TRAILS THE MAIN SYSTEM. AS THAT MOVES INTO THE
PLAINS I DO BELIEVE WE WILL BE SEEING MUCH BETTER RIDGING OVER THE
WESTERN PLAINS AND MOUNTAIN STATES. THAT WILL FINALLY BRING IN 850
TEMPERATURES IN THE 15 BELOW RANGE INTO OUR AREA AND UNLIKE THE PAST
MONTH OR SO...THIS COLD PUSH WILL NOT LEAVE SO QUICKLY. THE GFS OUT
TO 16 DAYS HAS BEEN SHOWING THIS RUN AFTER RUN NOW FOR A WEEK. THE
CFSV2 ENSEMBLES SHOW SNOW COVER DOWN TO TENNESSEE BY FRIDAY THE
18TH. THIS HAS BEEN CONSISTENT IN THE CFSV2 FOR OVER A WEEK TOO.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 710 AM EST SAT DEC 5 2015
THE BIG QUESTION FOR TODAY IS WILL THE FOG REALLY BREAK UP TODAY?
THE LATEST RUN OF THE RAP MODEL (11Z) SHOWS THE FOG BREAKING UP AT
GRR..BTL AND LAN BY 19Z OR SO BUT HOLDING IN AT JXN AND AZO. GIVEN
WE HAVE SOUTH WINDS AT THE SURFACE AND THE FOG GOES SOUTH INTO
NORTHERN KENTUCKY AND THAT THIS IS DECEMBER...THIS FOG MAY WELL
LAST INTO THIS AFTERNOON. I WENT WITH THE IDEA THE FOG WOULD BREAK
UP AT ALL TAF SITES BY EARLY AFTERNOON BUT I WILL ADMIT THAT WAS
AN OPTIMIST FORECAST.
THERE IS AN ISSUE WITH THE FOG COMING BACK TONIGHT. THE LATEST RUN
OF THEN NAM SHOWS 20 TO 25 KNOT WINDS IN THE BOUNDARY LAYER
BETWEEN 03Z AND 09Z BUT THOSE WINDS LET UP AFTER 09Z. IT MAY WELL
BE THAT IS A BIG ENOUGH WINDOW...GIVEN IT IS DECEMBER TO THAT
DENSE FOG TO COME BACK. SO I DID BRING DENSE FOG IN TOWARD SUNDAY
MORNING.
&&
.MARINE...
ISSUED AT 320 AM EST SAT DEC 5 2015
SOUTHERLY WINDS AROUND 5 TO 15 KTS WILL PRODUCE WAVE HEIGHTS
RANGING FROM 1 TO AS HIGH AS 4 FEET TODAY... HIGHEST UP AROUND BIG
AND LITTLE SABLE POINTS. WAVE HEIGHTS COULD BRIEFLY FLIRT WITH
SMALL CRAFT CRITERIA LATE THIS AFTERNOON AND TONIGHT NORTH OF
WHITEHALL BUT IT IS TOO MARGINAL FOR A SMALL CRAFT ADVISORY AT
THIS TIME.
&&
.HYDROLOGY...
ISSUED AT 1152 AM EST FRI DEC 4 2015
RIVERS ARE WELL WITHIN BANKS AND FALLING. WITH LITTLE
PRECIPITATION EXPECTED UNTIL AT LEAST THE LATTER HALF OF NEXT
WEEK... FLOODING CONCERNS ARE MINIMAL.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...FREEZING FOG ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR
MIZ056>059-064>067-071>074.
LM...NONE.
&&
$$
UPDATE...DUKE
SYNOPSIS...LAURENS
SHORT TERM...LAURENS
LONG TERM...WDM
AVIATION...WDM
HYDROLOGY...CAS
MARINE...LAURENS
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
709 AM EST SAT DEC 5 2015
LATEST UPDATE...
UPDATE/AVIATION
.SYNOPSIS...
ISSUED AT 320 AM EST SAT DEC 5 2015
HIGH PRESSURE WILL PRODUCE FAIR AND MILD WEATHER THROUGH THE
WEEKEND. HOWEVER AREAS OF DENSE FOG THIS MORNING WILL CAUSE
HAZARDOUS TRAVEL CONDITIONS. TEMPERATURES WILL CONTINUE TO AVERAGE
AT LEAST TEN TO FIFTEEN DEGREES ABOVE NORMAL THROUGH THE UPCOMING
WEEK.
&&
.UPDATE...
ISSUED AT 710 AM EST SAT DEC 5 2015
AS FORECAST BY THE HRRR RAP AND NAM MODELS THE FOG CONTINUES TO
SPREAD NORTHWARD. THERE WAS A BRIEF THINNING OF THE FOG OVER THE
GRAND RAPIDS TO NEAR KALAMAZOO AREA BUT THE THOSE SAME MODELS
HANDLED THAT NICELY TOO. IN FACT THE RAP MODEL SHOWED THE FOG
THINNING WHERE IT THINNED ONLY TO THICKEN TOWARD MORNING. THIS WAS
RELATED TO THE MORE WESTERLY WINDS EARLY THIS MORNING BRINGING IN
WARMER AIR BUT AS WINDS TURNED MORE TO THE SOUTH OVER THE PAST 2
HOURS THAT BROUGHT THE BELOW FREEZING AIR NORTHWARD AND THICKENED
THE FOG ONCE AGAIN. GIVEN THIS IS DECEMBER AND THAT THE FOG
EXTENDS SOUTH TO NEAR THE OHIO RIVER...IT WOULD SEEM IT WILL BE
AWHILE TILL IT BURNS OFF. THE HIGH RESOLUTION MODELS MIX OUT THE
FOG BETWEEN 11 AM AND 2 PM.
WE WILL HAVE TO WATCH FOG OVERNIGHT... THE LATEST RUN OF THE NAM
SHOWS WINDS DIMINISHING AFTER 04 AM...THAT WOULD ALLOW THE FOG TO
REFORM AGAIN.
&&
.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 320 AM EST SAT DEC 5 2015
A FREEZING FOG ADVISORY REMAINS IN EFFECT FOR ALL OF OUR FCST AREA
THROUGH 15Z THIS MORNING. SFC OBS/GROUND TRUTH REPORTS CONTINUE TO
INDICATE AREAS OF DENSE FOG ACROSS MUCH OF OUR FCST AREA. THIS IN
CONJUNCTION WITH SFC TEMPS AT OR BELOW FREEZING ACROSS PORTIONS OF
OUR AREA WILL RESULT IN HAZARDOUS TRAVEL CONDITIONS THROUGH MID
MORNING.
FOG WILL GRADUALLY DISSIPATE LATE THIS MORNING AND SKIES ARE
EXPECTED TO BECOME PARTLY TO MOSTLY SUNNY THIS AFTERNOON WITH
SUBSIDENCE UNDER THE HIGH PRESSURE RIDGE. IT WILL BECOME MILD AGAIN
TODAY WITH HIGH TEMPS REACHING THE MIDDLE TO UPPER 40S (00Z MET
NUMERICAL GUIDANCE MAXES ARE MUCH TOO COOL). THE HIGH PRESSURE RIDGE
WILL CONTINUE IN CONTROL OF THE WX PATTERN AND BRING FAIR WEATHER
THROUGH MONDAY.
.LONG TERM...(MONDAY NIGHT THROUGH FRIDAY)
ISSUED AT 320 AM EST SAT DEC 5 2015
THE SHORT STORY IS WARMER THAN NORMAL TEMPERATURES WILL BE FOLLOWED
MUCH WARMER THAN NORMAL TEMPERATURES LATER IN THE WEEK. WE WILL
TREND INTO A MUCH WETTER PATTERN AS WE HEAD TOWARD NEXT WEEKEND.
FOR THE MOST PART THE MODELS HAVE BEEN VERY CONSISTENT IN THE LARGE
SCALE DETAIL FOR THIS COMING WEEK. OUR VERY ACTIVE PACIFIC WAVE
TRAIN CONTINUES TO FEED SYSTEMS ON SHORE ABOUT EVERY TWO DAYS. WITH
THE SPLIT FLOW MOST OF THE PRECIPITATION HAS BEEN WELL NORTH IN
CANADA AND THIS COMING WEEK WE WILL SEE A LITTLE RAIN TRACK JUST
SOUTH OF MICHIGAN WITH THE SOUTHERN STREAM EARLY IN THE WEEK.
HOWEVER AS OUR VERY IMPRESSIVE 180 KNOT EAST ASIAN JET CORE (WE
HAVE BEEN FOLLOWING THIS ALL WEEK) GETS CLOSER TO WESTERN NORTH
AMERICA THE WAVES MOVING ON SHORE WILL AMPLIFY. THIS WILL
INCREASE THE FLOW OF GULF MOISTURE NORTH AND ALSO INCREASE JUST
HOW FAR NORTH THAT MOISTURE GETS.
IT SEEMS TO ME THE STORM NOW OFF THE WEST COAST (LOOKS GREAT ON THE
1 AM WATER VAPOR LOOPS...CHECK IT OUT OF YOU CAN) WILL BE OUR
WEDNESDAY SYSTEM. THIS ONE MAY HAVE ENOUGH WAVE LENGTH AS IT MOVES
TROUGH THE CENTRAL PLAINS TO GIVE US A FEW SHOWERS WEDNESDAY.
THERE WILL BE ONE MORE SYSTEM COMING THROUGH BEFORE THE SYSTEM WITH
THAT EAST ASIAN JET CORE OVER 180 KNOTS MOVES ONSHORE. THAT ONE
REACHES US IN THE FRIDAY TIME FRAME. THAT WILL BE MORE AMPLIFIEDTHAN
THE WEDNESDAY SYSTEM SO EXPECT A MORE WIDESPREAD RAIN EVENT WITH
THAT ONE.
MORE THAN LIKELY OUR TEMPERATURE FORECAST IS TO CONSERVATIVE... I
BELIEVE WE COULD SEE ACTUAL TEMPERATURE AS MUCH AS 5 TO 10 DEGREES
WARMER THAN WE ARE FORECASTING BY LATE IN THE PERIOD.
.WEEK TWO FORECAST...(SATURDAY THROUGH FRIDAY)
OF COURSE THE MAIN SHOW COMES THE NEXT WEEKEND INTO THE MIDDLE OF
THE FOLLOWING WEEK. BOTH THE ECMWF AND GFS SHOW THE AO AND NAO TENDING
TOWARD NEGATIVE VALUES THEN AND THE PNA GOING POSITIVE. ALL THAT
WOULD SUGGEST WESTERN RIDGE AND EASTERN TROUGH. THIS GOES WELL
WITH THE PROGRESSION OF THAT EAST ASIAN JET CORE. THE MAIN ENERGY
FOR THIS SYSTEM WILL COME TROUGH THE GREAT LAKES DURING THE
WEEKEND OF THE 12TH (SATURDAY). TIMING MAY BE SLOWER THAN I AM
SAYING BUT THE SYSTEM IN THE TIME FRAME OF SUNDAY THE 13TH COULD
BE A VERY DEEP SURFACE LOW WITH A LOT OF WIND AND A STRONG SURGE
OF EVERY WARM AIR. IT IS THIS SYSTEM THAT I THINK WILL BEING US
RECORD OR NEAR RECORD HIGHS IN THE MID 60S SATURDAY OR SUNDAY.
FOR THOSE WAITING FOR SNOW AND COLD... YOU MAY GET YOUR WISH BY THE
MIDDLE TO END OF THAT WEEK (THINK THE 15TH TO 18TH). THERE IS ONE
MORE SHORTWAVE THAT TRAILS THE MAIN SYSTEM. AS THAT MOVES INTO THE
PLAINS I DO BELIEVE WE WILL BE SEEING MUCH BETTER RIDGING OVER THE
WESTERN PLAINS AND MOUNTAIN STATES. THAT WILL FINALLY BRING IN 850
TEMPERATURES IN THE 15 BELOW RANGE INTO OUR AREA AND UNLIKE THE PAST
MONTH OR SO...THIS COLD PUSH WILL NOT LEAVE SO QUICKLY. THE GFS OUT
TO 16 DAYS HAS BEEN SHOWING THIS RUN AFTER RUN NOW FOR A WEEK. THE
CFSV2 ENSEMBLES SHOW SNOW COVER DOWN TO TENNESSEE BY FRIDAY THE
18TH. THIS HAS BEEN CONSISTENT IN THE CFSV2 FOR OVER A WEEK TOO.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 710 AM EST SAT DEC 5 2015
THE BIG QUESTION FOR TODAY IS WILL THE FOG REALLY BREAK UP TODAY?
THE LATEST RUN OF THE RAP MODEL (11Z) SHOWS THE FOG BREAKING UP AT
GRR..BTL AND LAN BY 19Z OR SO BUT HOLDING IN AT JXN AND AZO. GIVEN
WE HAVE SOUTH WINDS AT THE SURFACE AND THE FOG GOES SOUTH INTO
NORTHERN KENTUCKY AND THAT THIS IS DECEMBER...THIS FOG MAY WELL
LAST INTO THIS AFTERNOON. I WENT WITH THE IDEA THE FOG WOULD BREAK
UP AT ALL TAF SITES BY EARLY AFTERNOON BUT I WILL ADMIT THAT WAS
AN OPTIMIST FORECAST.
THERE IS AN ISSUE WITH THE FOG COMING BACK TONIGHT. THE LATEST RUN
OF THEN NAM SHOWS 20 TO 25 KNOT WINDS IN THE BOUNDARY LAYER
BETWEEN 03Z AND 09Z BUT THOSE WINDS LET UP AFTER 09Z. IT MAY WELL
BE THAT IS A BIG ENOUGH WINDOW...GIVEN IT IS DECEMBER TO THAT
DENSE FOG TO COME BACK. SO I DID BRING DENSE FOG IN TOWARD SUNDAY
MORNING.
&&
.MARINE...
ISSUED AT 320 AM EST SAT DEC 5 2015
SOUTHERLY WINDS AROUND 5 TO 15 KTS WILL PRODUCE WAVE HEIGHTS
RANGING FROM 1 TO AS HIGH AS 4 FEET TODAY... HIGHEST UP AROUND BIG
AND LITTLE SABLE POINTS. WAVE HEIGHTS COULD BRIEFLY FLIRT WITH
SMALL CRAFT CRITERIA LATE THIS AFTERNOON AND TONIGHT NORTH OF
WHITEHALL BUT IT IS TOO MARGINAL FOR A SMALL CRAFT ADVISORY AT
THIS TIME.
&&
.HYDROLOGY...
ISSUED AT 1152 AM EST FRI DEC 4 2015
RIVERS ARE WELL WITHIN BANKS AND FALLING. WITH LITTLE
PRECIPITATION EXPECTED UNTIL AT LEAST THE LATTER HALF OF NEXT
WEEK... FLOODING CONCERNS ARE MINIMAL.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...FREEZING FOG ADVISORY UNTIL 10 AM EST THIS MORNING FOR
MIZ037>040-043>046-050>052-056>059-064>067-071>074.
LM...NONE.
&&
$$
UPDATE...WDM
SYNOPSIS...LAURENS
SHORT TERM...LAURENS
LONG TERM...WDM
AVIATION...WDM
HYDROLOGY...CAS
MARINE...LAURENS
AREA FORECAST DISCUSSION
NWS DULUTH MN
537 AM CST SAT DEC 5 2015
.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 351 AM CST SAT DEC 5 2015
MINNESOTA IS IN A WARM SECTOR AHEAD OF A COLD FRONT EXTENDING NORTH-
SOUTH ACROSS THE DAKOTAS FROM A SURFACE LOW OVER NORTHERN MANITOBA.
THE WARM SECTOR IS QUITE MILD...WITH SURFACE TEMPERATURES IN THE
MIDDLE AND UPPER 30S ACROSS MOST OF NORTHERN MINNESOTA AND
WISCONSIN. BEHIND THE COLD FRONT IS NOT DRAMATICALLY COLDER BUT
TEMPERATURES DO FALL INTO THE UPPER 20S AND LOWER 30S FAIRLY
QUICKLY. THIS COLD FRONT TO SLOWLY MOVE INTO THE FORECAST AREA
TODAY...BECOMING MORE AND MORE DIFFUSE AS IT MOVES EAST TONIGHT AND
EARLY SUNDAY. THIS FEATURE TO BE A FOCUS FOR MID LEVEL MOISTURE TO
STREAM UP INTO THE AREA AND WITH SOME WEAK LIFT ALONG THE BOUNDARY
HAVE PUT IN SOME SHOWERS TONIGHT AND EARLY SUNDAY MORNING. MODELS
ARE TRYING TO PUT IN A NEARLY SATURATED BOUNDARY LAYER...BUT HAVE
SIGNIFICANT CONCERNS ON THIS AS CURRENT MODEL SOUNDINGS ARE OVER
SATURATED AND TOO COLD AT THE SURFACE NOW...AND ONLY GET WORSE IN
THE NEXT 24 HOURS. IN ADDITION THERE IS NO SIGN OF OF STRATUS IN
THE UPSTREAM AIRMASS OVER NORTH DAKOTA AND SOUTHERN
MANITOBA/SASKATCHEWAN...AND WOULD PREFER TO SEE SOME SIGNS OF IT
THERE BY NOW. WE HAVE ALSO SEEN A PATTERN RECENTLY OF THE MODELS
OVERDOING THE LOW LEVEL MOISTURE IN THIS PATTERN. THUS...HAVE
SWITCHED THE FORECAST OVER TO SLIGHT CHANCES OF SHOWERS. WITH THE
CLOUD COVER AROUND HAVE ALSO REDUCED THE DIURNAL RANGE AND BROUGHT
UP THE MIN TEMPS IN THE VICINITY OF THE FRONT FOR MAINLY LIQUID
SHOWERS IN THE EVENING... TRANSITIONING TO SNOW OVERNIGHT.
.LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY)
ISSUED AT 351 AM CST SAT DEC 5 2015
THE LONG TERM IS STARTING TO SOUND LIKE A BROKEN RECORD...AS
UNSEASONABLY WARM WEATHER IS EXPECTED TO CONTINUE THROUGHOUT THE
PERIOD. UPPER LEVEL RIDGING SUNDAY NIGHT AND EARLY MONDAY WILL BRING
A QUIET AND WARM START TO THE WORK WEEK. WITH A GOOD DEAL OF
SUNSHINE...TEMPERATURES SHOULD TOP OUT IN THE 39 TO 44 DEGREE RANGE.
TO PUT THAT IN PERSPECTIVE...NORMAL HIGH TEMPERATURES FOR THIS TIME
OF YEAR ARE GENERALLY IN THE LOW TO MID 20S. THE UPPER LEVEL FLOW
WILL THEN QUICKLY TRANSITION TO A QUASI-ZONAL FLOW BY MONDAY AND
MONDAY NIGHT...WITH A SHORTWAVE PUSHING EASTWARD ACROSS THE CWA
LATER TUESDAY AND TUESDAY NIGHT. WILL MENTION SOME SMALL POPS
REGARDING THIS SYSTEM BUT BEST CHANCE LOOKS TO BE SOUTH OF THE CWA.
THE MODELS ONCE AGAIN START TO DIVERGE FROM WEDNESDAY INTO FRIDAY OF
NEXT WEEK...SO THE CONFIDENCE IN ANY PARTICULAR SOLUTION CONTINUES
TO BE LOWER THAN AVERAGE. IN TERMS OF SENSIBLE WEATHER THE IMPACT IS
NOT TOO GREAT...AS IT DOES LOOK LIKE PRECIPITATION CHANCES WILL
EXIST NO MATTER WHICH MODEL...AND TEMPS APPEAR TO CONTINUE ABOVE
NORMAL. THROUGHOUT THE PERIOD WE SHOULD SEE HIGH TEMPERATURES RANGE
FROM THE MID 30S TO THE MID 40S...WITH LOWS IN THE 20S TO 30S.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 533 AM CST SAT DEC 5 2015
VFR CONDITIONS ARE EXPECTED TO MAKE A DRAMATIC TRANSITION AS THE
DAY WEARS ON ACROSS THE TAF SITES. HIGH RESOLUTION MODELS SUCH AS
THE HRRR AND RAP INDICATE THE DEVELOPMENT IN PLACE OF LOW CLOUDS
AND FOG AS THE DAY WEARS ON. THE LOW CLOUDS AND FOG ARE EXPECTED
TO DEVELOP ALONG AND AHEAD OF A COLD FRONT THAT WILL MOVE ACROSS
THE NORTHLAND TODAY AND TONIGHT. THE FRONT WILL BRING SOME SPOTTY
SHOWERS OR DRIZZLE...BUT THE BIG STORY WILL BE THE DEVELOPMENT OF
MVFR AND EVENTUALLY IFR CIGS/VSBYS. THESE CONDITIONS WILL PERSIST
INTO THE NIGHT. STRONG LLWS WILL CONTINUE AT LEAST THROUGH THE
MORNING AND INTO THE AFTERNOON IN SOME SPOTS.
&&
.PRELIMINARY POINT TEMPS/POPS...
DLH 41 31 42 27 / 10 20 0 0
INL 42 26 39 25 / 10 0 0 0
BRD 41 27 41 24 / 10 10 0 0
HYR 45 33 42 22 / 10 20 0 0
ASX 47 34 43 25 / 10 20 0 0
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
LS...SMALL CRAFT ADVISORY UNTIL 10 PM CST THIS EVENING FOR LSZ121-
146>148.
&&
$$
SHORT TERM...LE
LONG TERM...DAP
AVIATION...DAP
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
556 AM CST SAT DEC 5 2015
.SHORT TERM: (Through Late This Afternoon)
Issued at 330 AM CST Sat Dec 5 2015
Once again, fog is the primary concern for the short term forecast
this morning. An expansive area of fog is advecting westward toward
the Mississippi River from Illinois and it looks likely to envelop
much of the STL Metro area before sunrise. Have already expanded
the dense fog advisory issued yesterday evening into east central
Missouri. HRRR and NARRE-TL look to have a pretty good handle on
the fog so far this morning...although they might be a little bit
too aggressive with the westward-southwestward expansion.
Regardless, both models keep visibility down through 14-15Z.
Improvement is pretty rapid between 16-18Z, so the timing of the
advisory still looks pretty good. Temperatures today should be
similar to yesterday, though some of the cooler readings over
central Illinois yesterday will likely expand further west-southwest
today due to the greater areal coverage of the fog today.
Carney
.LONG TERM: (Tonight through Friday)
Issued at 330 AM CST Sat Dec 5 2015
An extended period of above average temps continues to look likely
for much of next week as the polar jet, with very few exceptions,
remains to our north. The flow will overall be low amplitude,
facilitating a progressive movement to any systems, and indeed, our
area will be treated to a series of storm systems originating over
the Pacific that will be quick hitting, which will incidentally,
limit their ability to moisten the column sufficiently to allow
pcpn.
The first system is slated for Sunday, and this looks to be the one
where confidence is highest that it will produce pcpn for some
areas. Models have come together nicely on timing now that it is
over land and can be sampled better, ranging from beginning Sunday
morning over northeast and central MO, to exiting southwest IL by
late Sunday evening. There is also good consensus on track, with
the strongest lift associated with the core of the system expected
over northern MO and central IL, and have placed highest PoPs in
these areas as a result--corresponding to our northern CWA. Even
then, moisture will struggle with this system, with its relatively
fast movement, northern track, very dry column already in place, and
no help whatsoever from low level flow. So highest PoPs for this
system look to be just below 50% in the north, trailing to slight
chance 20% in southern MO and IL. Pcpn-types should be all rain
with warm air aloft and above freezing surface temps.
Additional fast moving Pacific systems will slide thru, Monday
night, Tuesday night, and again Thursday-Friday, but with marginal
conditions at best and specific tracks enough in doubt (large enough
model spreads) whereby they will need all the lift they can muster
to generate pcpn, leaned dry on the forecast for much of next week
for now, with PoPs possibly needed down the road as track confidence
increases.
Otherwise, very mild week on tap after Sunday, with what should be
daytime maxes at least in the 50s, possibly 60s, and nighttime mins
above freezing.
A pattern change looks set to occur for the third week of December,
with large height falls and a longwave TROF setting up over the
central CONUS. This should open the way for cold air intrusions
heading towards Christmas that we have not really seen thus far this
late autumn and early winter.
TES
&&
.AVIATION: (For the 12z TAFs through 12z Sunday Morning)
Issued at 538 AM CST Sat Dec 5 2015
Expansive area of fog and low stratus over Illinois was spreading
westward into east central Missouri; however, the western edges of
the fog are shredding out. High resolution/short range model
guidance is pretty insistent that at least some of these holes
will fill in over the next 90 minutes...although I have my doubts.
Regardless, widespread IFR ceilings/visibilities will prevail
east of the Mississippi river this morning until at least 16-18Z,
and likely over a small part of east central Missouri until
14-15Z. Elsewhere and otherwise, expect VFR flight conditions. and
light southeast flow.
Specifics for KSTL:
The approach of fog and low stratus toward Lambert has slowed
significantly over the past 60-90 minutes, and the once unbroken
fog bank is shredding on its western fringes. That being said,
satellite pictures and area traffic cameras show very low
visibilities within 5 miles of the airport, so I feel compelled to
keep some mention of IFR in the TAF. Additionally, high
resolution/short range model guidance is pretty insistent that at
least some of the holes on the western fringes of the fog bank will
fill in over the next 90 minutes...although I have my doubts. Fog
will persist in the area of the terminal for at least a couple of
hours this morning. VFR flight conditions with southeast flow will
prevail thereafter.
Carney
&&
.LSX WATCHES/WARNINGS/ADVISORIES:
MO...Dense Fog Advisory until noon CST today FOR Jefferson MO-St.
Charles MO-St. Louis City MO-St. Louis MO-Ste. Genevieve MO.
IL...Dense Fog Advisory until noon CST today FOR Bond IL-Calhoun IL-
Clinton IL-Fayette IL-Greene IL-Jersey IL-Macoupin IL-
Madison IL-Marion IL-Monroe IL-Montgomery IL-Randolph IL-
St. Clair IL-Washington IL.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
644 AM EST SAT DEC 5 2015
.SYNOPSIS...
CLOUDS WILL GRADUALLY GIVE WAY TO SUNSHINE TODAY WITH TEMPERATURES
IN THE 40S. FULL SUNSHINE IS EXPECTED SUNDAY WITH HIGHS INTO THE
50S. DRY AND MILD WEATHER WILL CONTINUE INTO MUCH OF NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
645 AM UPDATE...
CLOUDS STILL HOLDING TOUGH OVER OUR AREA WITH THE ONLY AREA SEEING
A CLEAR SKY OVER SULLIVAN AND PIKE COUNTIES. BASED ON THIS AND THE
LATEST RUC SLOWING THE CLEARING TODAY, CONTINUED A CLOUDY SKY FOR
MOST OF THE AREA THROUGH LATE THIS MORNING. A CLEARING TREND FROM
SOUTH TO NORTH IS STILL EXPECTED BUT NOT UNTIL LATE MORNING NEPA,
AFTERNOON SOUTHERN TIER OF NY, AND PERHAPS NOT UNTIL TOWARD SUNSET
CENTRAL NY. PREVIOUS AFD, INCLUDING A SUNNIER END TO THE WEEKEND,
IS BELOW.
315 AM UPDATE...
JUST A CLOUD AND TEMPERATURE FORECAST TODAY. LOW LEVEL CLOUDS HAVE
EXPANDED TO COVER ALMOST ALL OF OUR FORECAST AREA, OUTSIDE OF
SULLIVAN COUNTY. WITH A NORTHERLY OR UPSLOPE COMPONENT OF THE
WIND, THIS IS NO SURPRISE GIVEN THE TIME OF THE MORNING. WITH
SURFACE HIGH PRESSURE MOVING OVERHEAD BY 12Z AND OUR WIND BECOMING
NEARLY CALM, SUBSIDENCE OR SINKING AIR WILL SLOWLY ERODE OUR CLOUD
DECK FROM SOUTH TO NORTH. WITH THAT IN MIND EXPECT A GRADUAL
INCREASE IN SUNSHINE TODAY BUT FROM THE NORTHERN TIER OF PA INTO
MUCH OF SOUTHERN NY, THIS MAY TAKE UNTIL AT LEAST MIDDAY TO OCCUR.
FARTHER NORTH TOWARD SYRACUSE, WE MAY NOT SEE CLEARING UNTIL LATER
THIS AFTERNOON. BASED ON THE CLOUDS I LOWERED HIGH TEMPS A BIT
TODAY WITH NEARLY STEADY TEMPS UNTIL A LATE DAY SPIKE IN TEMPS
OCCURRING WITH OUR CLEARING. WITH A CLEAR SKY AND NEAR CALM
CONDITIONS TONIGHT WILL BE MUCH COLDER THAN RIGHT NOW, WITH MANY
AREAS FALLING BACK INTO THE 20S.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
315 AM UPDATE....
A BEAUTIFUL END TO OUR WEEKEND, WITH MORE SUNSHINE EXPECTED AND IN
RESPONSE IT WILL BE WARMER AT THE SURFACE. HIGHS WILL BE IN THE
50S OR WELL ABOVE OUR EARLY DECEMBER AVERAGE OF 36 TO 40 DEGREES!
A DISTURBANCE IN THE JET STREAM WINDS ALOFT WILL MOVE OUT OF THE
OHIO VALLEY MONDAY, AND ACROSS OUR AREA MONDAY NIGHT. ANY
PRECIPITATION (IN THE FORM OF RAIN) ASSOCIATED WITH THIS SYSTEM
WILL REMAIN SOUTH OF OUR AREA. THE IMPACT OF THE DISTURBANCE
HOWEVER WILL BE A COOLER POCKET OF AIR MOVING OVER AREA AREA. THE
RESULT WILL BE HIGHS MONDAY ABOUT 5 TO 8 DEGREES COOLER THAN WHAT
WE WILL SEE TODAY. STILL WE ARE TALKING WELL INTO THE 40S FOR
MOST, AND NEAR 50 FAR SOUTH. FOR DECEMBER 7TH, NOT TOO SHABBY!
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
3 PM FRI UPDATE...
ANOTHER WARM PERIOD WITH LITTLE PRECIPITATION. HIGHS IN THE 40S
AND LOWS IN THE 30S. FOLLOWED WPC LEAD AND LEFT POPS AT SLIGHT
CHANCE WED NGT TO FRIDAY. A MORE ACTIVE PATTERN WITH A ZONAL
PATTERN BECOMING AMPLIFIED END OF WEEK. A WEAK CLOSED UPPER LEVEL
LOW MOVES THROUGH MONDAY AND EAST TUESDAY. HIGH PRESSURE AND DRY
AIR SHOULD KEEP ANY RAIN TO THE COASTAL PLAIN AND OUT OF OUR CWA.
WED TO SAT MODEL DISAGREEMENT BUT A SERIES OF SHORT WAVES AS AN
UPPER LEVEL TROF APPROACHES. EURO DEEPER AND WETTER THAN GFS.
WEATHER NOT A PROBLEM WITH TEMPERATURES AT THE SFC AND 850MB ABOVE
FREEZING.
&&
.AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...
STUBBORN SC DECK CONTS OVER THE AREA THIS MRNG...AND MAY LINGER
FOR MUCH OF THE DAY. MESO MODELS SHOW SLOW EROSION OF THE DECK
FROM THE SOUTH...NOT RCHG RME AND SYR UNTIL ALMOST DARK. WILL CONT
WITH MVFR CIGS ALL STATIONS THIS MRNG...SLOWLY BCMG SCT FROM SOUTH
TO NORTH BEGINING ARND 16Z AT AVP. UNDER SFC HIPRES...WINDS WILL
REMAIN LGT. MAINLY CLR SKIES XPCTD OVRNGT.
.OUTLOOK...
SAT NIGHT THROUGH WED...QUIET PERIOD. MAINLY VFR.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...HEDEN
NEAR TERM...HEDEN
SHORT TERM...HEDEN
LONG TERM...TAC
AVIATION...DGM
AREA FORECAST DISCUSSION
NWS BUFFALO NY
637 AM EST SAT DEC 5 2015
.SYNOPSIS...
HIGH PRESSURE WILL BUILD INTO THE REGION TODAY WITH A GRADUAL
RETURN TO SUNSHINE AND ABOVE AVERAGE TEMPERATURES. THE CLEAR
SKIES AND WARM TEMPERATURES WILL CONTINUE SUNDAY AND RIGHT THROUGH
THE FIRST HALF OF NEXT WEEK AS HIGH PRESSURE REMAINS IN CONTROL.
&&
.NEAR TERM /THROUGH TONIGHT/...
A WIDESPREAD LOW STRATUS DECK LODGED UNDERNEATH A STEEP
SUBSIDENCE INVERSION WITHIN THE BACKGROUND OF WEAK SURFACE RIDGING
CONTINUING TO ENCOMPASSING MUCH OF WESTERN NEW YORK. 1000-975 MB
MOISTURE FIELDS ON THE HRRR AND RAP CONCUR WITH THE CURRENT
PLACEMENT OF THIS CLOUD DECK. CLOUDS WILL BE STUBBORN TO CLEAR
WITH CURRENT TRENDS POINTING TOWARD TAKING A DECIDEDLY MORE
PESSIMISTIC OUTLOOK ON CLOUD COVER NEARLY AREAWIDE THROUGH THE
MORNING PERIOD. ELEMENT OF SHALLOW FOG WITHIN THIS NEAR SURFACE
MOISTURE PLUME AS WELL.
STRATUS/FOG SHOULD ERODE FOR THE MOST PART BY AFTERNOON...ALTHOUGH
COULD CONTINUE TO LINGER ACROSS INTERIOR SECTIONS EAST OF LAKE
ONTARIO. INCREASING SUNSHINE ALONG WITH DEVELOPING WARM AIR
ADVECTION PATTERN SHOULD GET AFTERNOON TEMPERATURES IN THE LOWER
50S ON THE LAKE PLAINS OF WESTERN NEW YORK AND MID TO UPPER 40S
ACROSS HIGHER TERRAIN AND THE EASTERN LAKE ONTARIO REGION.
BY SUNDAY...SURFACE HIGH PRESSURE AND MID LEVEL RIDGING WILL SHIFT
OFF THE MID-ATLANTIC AND NEW ENGLAND COASTS. AMPLE SUNSHINE ALONG
WITH A SOUTHERLY FLOW AND 850 MB TEMPERATURES NEAR +6C WILL SUPPORT
HIGHS REACHING THE LOWER TO MID 50S.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
SURFACE HIGH PRESSURE AND MID-LEVEL RIDGING WILL SHIFT OFF THE MID-
ATLANTIC AND NEW ENGLAND COASTS THROUGH SUNDAY BEFORE A SURFACE
TROUGH AND MID-LEVEL CLOSED LOW PASS SOUTH OF OUR FORECAST AREA ON
MONDAY. MODEL DIAGNOSTIC DISCUSSION REFERS TO HIGH CONFIDENCE WITH
THE STRENGTH AND PLACEMENT OF THIS CLOSED UPPER LOW AND ITS
ASSOCIATED EFFECT ON LOCAL SENSIBLE WEATHER. ANY SYNOPTIC LIFT AND
MOISTURE WORTH MENTIONING WILL BE COLLOCATED WITH THE LOW CENTER...
WELL TO OUR SOUTH...LEAVING WESTERN AND CENTRAL NEW YORK WITH FAIR
WEATHER THROUGH THE BEGINNING OF NEXT WEEK. MAINLY CLEAR SKIES WILL
PROMOTE PLENTY OF SUNSHINE SUNDAY AND MONDAY WITH ONLY A FEW HIGH
CLOUDS STREAMING NORTH FROM THE SOUTHERN SYSTEM ON MONDAY NIGHT.
SOUTHERLY FLOW AND 850MB TEMPS OF +8C WILL SUPPORT HIGHS REACHING
INTO THE LOWER TO MIDDLE 50S ON SUNDAY WITH UPPER 40S TO LOW 50S
EAST OF LAKE ONTARIO. THEN A NORTHERLY SHIFT TO THE WINDS AND COLD
ADVECTION ON MONDAY WILL KNOCK 850MB TEMPS BACK TOWARD 0C KEEPING
SURFACE HIGHS ABOUT 10F COOLER.
GOOD RADIATIONAL COOLING EACH NIGHT WILL ALLOW LOWS TO RANGE FROM
THE LOWER TO MIDDLE 30S NEAR THE LAKES TO THE UPPER 20S WELL INLAND.
LIGHT WINDS WILL ALLOW RIVER VALLEY FOG IN THE SOUTHERN TIER VALLEYS
WHICH COULD MAKE FOR SOME SLICK ROADWAYS IN AREAS WHERE SURFACE
TEMPS ALSO FALL BELOW FREEZING.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
A WAVY PACIFIC FLOW IS EXPECTED TO GENERALLY KEEP MILD TEMPERATURES
AND BENIGN WEATHER THROUGH NEXT WEEK. 04/12Z GFS AND ECMWF MODELS
ARE NOT WELL ALIGNED WITH THE 500MB PATTERN WITH EACH MODEL SHOWING
A DIFFERENCE IN TIMING AND LOCATION OF SUBTLE SHORTWAVE TROUGHS
MOVING ACROSS THE CONUS. THIS LEADS TO A LOW CONFIDENCE FORECAST FOR
MORE DEFINITIVE TIMING OF ANY MINOR PRECIPITATION EVENTS THAT MAY
IMPACT OUR FORECAST AREA.
IT APPEARS THAT A DEEPENING STORM OFF THE EAST COAST TUESDAY WILL
NOT BE A THREAT TO WESTERN AND CENTRAL NEW YORK AT THIS TIME
ALTHOUGH THE 04/12Z ECMWF HAS SHIFTED A BIT FURTHER NORTH WITH THE
TRACK OF THE CLOSED 500MB LOW. AFTER THIS THE FORECAST ONLY INCLUDES
SLIGHT CHANCE POPS FROM WEDNESDAY NIGHT INTO FRIDAY DUE TO THE POOR
MODEL AGREEMENT. DAYTIME TEMPERATURES WILL RUN ON THE MILD SIDE FOR
THIS TIME OF YEAR WITH OVERNIGHT LOWS CLOSER TO SEASONAL NORMALS.
HIGHS WILL RANGE FROM THE MID 40S TO AROUND 50 EACH DAY WITH
OVERNIGHT LOWS RANGING IN THE MID 30S NEAR THE LAKES TO UPPER 20S
INLAND.
&&
.AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...
A WIDESPREAD STRATUS DECK WILL STUBBORNLY PERSIST THROUGH THE
MORNING WITH MOST LOCATIONS SEEING MVFR CIGS...BUT SOME IFR CIGS
ACROSS THE HIGHER ELEVATIONS OF THE SOUTHERN TIER AND THE TUG
HILL. CLEARING FROM WEST TO EAST SHOULD BE FAIRLY ROBUST
AFTER 17Z...WITH VFR CONDITIONS AND LIGHT WINDS BY MID TO LATE
AFTERNOON.
OUTLOOK...
SUNDAY TO WEDNESDAY...VFR.
&&
.MARINE...
HIGH PRESSURE WILL BUILD INTO THE LOWER LAKES THIS WEEKEND AND
REMAIN IN PLACE THROUGH THE MIDDLE OF NEXT WEEK...PROVIDING A RARE
EXTENDED STRETCH OF LIGHT WINDS AND FLAT WAVE ACTION ON THE LOWER
LAKES.
&&
.CLIMATE...
TEMPERATURES ACROSS WESTERN AND NORTH CENTRAL NEW YORK HAVE AVERAGED
WELL ABOVE NORMAL SINCE HALLOWEEN...LARGELY DUE TO A POWERFUL EL
NINO EVENT THAT IS IN PLACE OVER THE EQUATORIAL PACIFIC. THE
STRENGTH OF THE CURRENT EL NINO IS SIMILAR TO THE HISTORIC ONE FROM
1997-98 WHEN OUR REGION BASKED IN ONE OF THE MILDEST WINTERS OF THE
PAST SIXTY YEARS.
THE MILDER WEATHER DID HAVE AN IMPACT ON LAKE SNOWS THAT SEASON.
SNOWFALL FOR THAT PARTICULAR WINTER AVERAGED WELL BELOW NORMAL...
WITH LAKE EFFECT AREAS ONLY RECEIVING ABOUT HALF AS MUCH SNOW AS
USUAL. THE LACK OF SNOWFALL WAS NOT AS PERCEPTIBLE IN NON-LAKE
EFFECT AREAS THOUGH AS A FAVORABLE SYNOPTIC STORM TRACK ALLOWED FOR
NEAR NORMAL AMOUNTS...WITH THE FINGER LAKES REGION ACTUALLY
EXPERIENCING MORE SNOW THAN NORMAL.
DURING THE PAST SIX WEEKS...THERE HAVE BEEN TWO NOTICEABLE
HEMISPHERIC PATTERNS THAT HAVE SUPPORTED THE MILD WEATHER. THE
FIRST IS DIRECTLY RELATED TO STRONG EL NINOS...THAT BEING AN
ANOMALOUSLY STRONG ASIAN/NORTH PACIFIC JET. NOT ONLY IS THIS JET
STRONGER NORMAL BUT IS APPEARS TO BE DISPLACED SEVERAL HUNDRED
MILES FURTHER NORTH. THE EFFECTS OF THIS ARE TWO FOLD. IT
SUPPRESSES THE DEVELOPMENT OF A WEST COAST RIDGE...WHICH WAS
DOMINANT THE PAST TWO WINTERS...AND IT ALSO HELPS TO FLOOD THE
BULK OF NORTH AMERICA WITH PACIFIC MODIFIED AIR. WHILE KEEPING
PACIFIC BASED AIR IN PLACE...THIS PATTERN ALSO BLOCKS ANY ATTEMPT
AT ANY REAL COLD AIR FROM MAKING ITS WAY SOUTH. TRUE COLD AIR UP
TO THIS POINT HAS BEEN LOCKED IN PLACE BETWEEN THE CANADIAN
ARCHIPELAGO AND SIBERIA...OR POLEWARD OF 60N.
THE OTHER KEY HEMISPHERIC FEATURE HAS BEEN THE PERSISTENCE OF AN
ICELANDIC LOW. THIS PATTERN ENHANCES THE MID AND UPPER LEVEL JET AS
IT EXITS NORTH AMERICA...THUS KEEPING A STRONG LOW AMPLITUDE FLOW
ACROSS THE NORTH ATLANTIC. WITHOUT ANY HIGH LATITUDE BLOCKING (EX
GREENLAND BLOCK)...THE STRONG WEST TO EAST JET CAN REMAIN DOMINANT.
THE RESULT IS PERSISTENT `MILD` WEATHER ACROSS THE EASTERN HALF OF
NORTH AMERICA AS WELL AS EUROPE (POSITIVE NAO TRAIT).
MEDIUM AND LONG RANGE GUIDANCE CONTINUES TO KEEP THIS GENERAL
PATTERN IN PLACE FOR THE FORESEEABLE FUTURE...SO A CHANGE TO THE
GENERAL MILD PATTERN IS NOT ANTICIPATED THROUGH AT LEAST MID MONTH.
ANY COLD AIR THAT IS NEEDED FOR SIGNIFICANT LAKE EFFECT WOULD HAVE
TO BE `MANUFACTURED` LOCALLY...WHICH IS NOT SOMETHING THAT IS
TYPICALLY EXPERIENCED FOR MESOSCALE EVENTS SUCH AS LAKE EFFECT.
SUCH A PROCESS IS MORE FAVORABLE FOR LARGER SYNOPTIC SYSTEMS.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...TMA
NEAR TERM...TMA
SHORT TERM...WCH
LONG TERM...SMITH
AVIATION...TMA
MARINE...TMA
CLIMATE...RSH
AREA FORECAST DISCUSSION
NWS AUSTIN/SAN ANTONIO TX
958 AM CST SAT DEC 5 2015
.UPDATE...
LOW CLOUDS ARE SLOWER TO BURN OFF OUT WEST THEN WE PREVIOUSLY
ANTICIPATED. HAVE UPDATED TO KEEP CLOUDS FOR A FEW MORE HOURS.
HOURLY TEMPERATURES WERE RUNNING BEHIND WARMING...BUT THINK HIGHS
LOOK GOOD. THE REST OF THE FORECAST LOOKS ON TRACK.
&&
.PREV DISCUSSION... /ISSUED 539 AM CST SAT DEC 5 2015/
AVIATION.../12Z UPDATE/
VFR CONDITIONS ARE EXPECTED WITH LIGHT AND VARIABLE WINDS THROUGH
THIS FORECAST PERIOD. CIRRUS WILL MOVE ACROSS THE WESTERN PORTIONS
TODAY FROM TIME TO TIME. KDRT WILL LIKELY SEE MVFR CIGS THIS
MORNING THROUGH 17Z. CIRRUS ACROSS THIS AREA IS CURRENTLY NOT
ALLOWING WIDESPREAD LOW CLOUD DEVELOPMENT. DO THINK LOW CLOUDS
SHOULD DEVELOP IN THE NEXT FEW HOURS. WILL CONTINUE TO MONITOR THE
TRENDS FOR FURTHER UPDATES. WINDS AT KDRT WILL BECOME SE AT 10-15
MPH AFTER 17Z THEN BACK TO EASTERLY AFTER 01Z AT 5-10 KNOTS.
PREV DISCUSSION... /ISSUED 332 AM CST SAT DEC 5 2015/
SHORT TERM (TODAY THROUGH SUNDAY)...
COOL MORNINGS WITH PLEASANT AFTERNOON TEMPERATURES EXPECTED TODAY
AND SUNDAY WITH SOME CLOUDS MIXED IN ACROSS THE RIO GRANDE VALLEY.
TEMPERATURES WILL RETURN TO NEAR AND SLIGHTLY ABOVE NORMAL SUNDAY
WITH HIGHS REACHING INTO THE MID TO UPPER 60S.
WATER VAPOR AND RAP ANALYSIS DEPICT A WEAK SHORTWAVE RIDGE OVER
TEXAS AND THE GULF COASTAL WATERS THAT IS ALLOWING FOR WEAK
MOISTURE RETURN IN THE 925-700MB LAYER. THE MAIN WEAK MOISTURE
TONGUE IS CONFINED TO THE RIO GRANDE VALLEY AS IT POOLS AGAINST
THE SIERRA DEL BURRO RANGE. AS A RESULT...EXPECT LOW CLOUDS TO
DEVELOP THROUGH THE MORNING HOURS ACROSS THE RIO GRANDE VALLEY
THAT WILL SLOWLY BREAK UP THROUGH THE DAY. LOCATIONS EAST OF U.S.
HIGHWAY 83 WILL REMAIN MOSTLY SUNNY WITH ONLY HIGH CLOUDS
STREAMING OVERHEAD. AREAS SEEING MORE CLOUDS OUT WEST WILL NOT
WARM AS MUCH AS CENTRAL AND EAST LOCATIONS WITH A NICE REBOUND INTO
THE LOW TO MID 60S EXPECTED TODAY. MAVMOS ALONG WITH SUPPORT FROM
RAW MODEL SOUNDING GUIDANCE APPEARS TO BE THE BEST ROUTE FOR
MAXIMUM HIGHS TODAY. MIXING HEIGHTS WILL TOP OUT NEAR 2-2.2KFT
NEAR 9-10C THAT WILL SUPPORT THESE HIGHER VALUES VS. THE SLIGHTLY
COOLER MET/ECSMOS. DID TRIM 1F DEGREE OFF MAX HIGHS FOR KDRT
GIVEN THE CLOUD INTERFERENCE THROUGH AT LEAST THE LATE MORNING.
EXPECT A NEAR COPY FOR SUNDAY WITH SOME MORNING CLOUDS ACROSS THE
RIO GRANDE VALLEY AGAIN AND TEMPERATURES AREAWIDE LIKELY 1-3F
DEGREES WARMER IN THE AFTERNOON. SOME LOCATIONS ACROSS THE COASTAL
PLAINS AND NEAR KSAT COULD PUSH THE 70F DEGREE MARK. A WEAK
DRYLINE WILL SHIFT THROUGH ON SUNDAY USHERING IN DRIER AIR WITH
N/NW WINDS AND ONLY LIMITED MID-LEVEL CLOUDS. NO COLD AIR IS
ASSOCIATED WITH THIS BOUNDARY AND THUS WE WILL CONTINUE TO WARM
THROUGH THE AFTERNOON DESPITE THE NORTH WINDS.
LONG TERM (MONDAY THROUGH FRIDAY)...
NO HAZARDS APPEAR LIKELY THROUGH THE LONG TERM WITH PLEASANT AND
ABOVE NORMAL TEMPERATURES EXPECTED THROUGH AT LEAST THURSDAY. RAIN
CHANCES WILL INCREASE GOING INTO NEXT SATURDAY AHEAD OF A STRONGER
COLD FRONT AND MID-LVL SYSTEM.
FROM EARLY NEXT WEEK TO MID WEEK...THE REGION WILL REMAIN SOUTH OF
THE ACTIVE JET STREAM AND VOID OF AIRMASS CHANGES. SURFACE HIGH
PRESSURE WILL REMAIN OVER THE NORTHERN GULF THROUGH MID-WEEK AND
WEAK SOUTHWEST FLOW ALOFT. PWATS WILL BE IN THE 0.4"-0.8" RANGE
AS WEAK SOUTH SURFACE WINDS ATTEMPT TO BRING HIGHER MOISTURE TO
THE REGION. BY THURSDAY...A STRONGER SHORTWAVE TROUGH ACROSS THE
CENTRAL PLAINS WILL PUSH A WEAK FRONT NEAR THE HILL COUNTRY BUT
ONLY LIMITED RAIN CHANCES FOR THE COASTAL PLAINS ARE EXPECTED
WHERE PWATS WILL RECOVER TOWARDS 1.3".
A MORE POWERFUL SYSTEM WILL APPROACH THE BIG BEND LATE FRIDAY
INTO THE WEEKEND THAT MAY AID IN SOME SCATTERED SHOWERS AND STORMS.
THE BEST DYNAMICS AND FORCING SILL APPEAR TO BE NORTH AND EAST
WHERE THE BETTER RAIN CHANCES WILL BE. PWAT RECOVER STILL APPEARS
LOW TO MODEST AT BEST AND WILL ADVERTISE 20-30% FOR NOW AND WATCH
THE MODEL EVOLUTION FOR THIS TIME FRAME.
&&
.PRELIMINARY POINT TEMPS/POPS...
AUSTIN CAMP MABRY 65 42 67 40 66 / 0 0 0 0 0
AUSTIN BERGSTROM INTL AIRPORT 64 39 66 37 65 / 0 0 0 0 0
NEW BRAUNFELS MUNI AIRPORT 66 41 67 40 67 / 0 0 0 0 0
BURNET MUNI AIRPORT 63 41 63 37 64 / 0 0 0 0 0
DEL RIO INTL AIRPORT 63 42 66 41 66 / 0 0 0 0 0
GEORGETOWN MUNI AIRPORT 62 43 64 35 64 / 0 0 0 0 0
HONDO MUNI AIRPORT 65 40 68 38 66 / 0 0 0 0 0
SAN MARCOS MUNI AIRPORT 64 40 66 40 65 / 0 0 0 0 0
LA GRANGE - FAYETTE REGIONAL 65 43 67 42 66 / 0 0 0 0 0
SAN ANTONIO INTL AIRPORT 65 42 68 42 66 / 0 0 0 0 0
STINSON MUNI AIRPORT 66 43 69 42 67 / 0 0 0 0 0
&&
.EWX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
MESOSCALE/AVIATION...RUNYEN
SYNOPTIC/GRIDS...05
PUBLIC SERVICE/DATA COLLECTION...30
AREA FORECAST DISCUSSION...UPDATED
NWS AUSTIN/SAN ANTONIO TX
539 AM CST SAT DEC 5 2015
.AVIATION.../12Z UPDATE/
VFR CONDITIONS ARE EXPECTED WITH LIGHT AND VARIABLE WINDS THROUGH
THIS FORECAST PERIOD. CIRRUS WILL MOVE ACROSS THE WESTERN PORTIONS
TODAY FROM TIME TO TIME. KDRT WILL LIKELY SEE MVFR CIGS THIS
MORNING THROUGH 17Z. CIRRUS ACROSS THIS AREA IS CURRENTLY NOT
ALLOWING WIDESPREAD LOW CLOUD DEVELOPMENT. DO THINK LOW CLOUDS
SHOULD DEVELOP IN THE NEXT FEW HOURS. WILL CONTINUE TO MONITOR THE
TRENDS FOR FURTHER UPDATES. WINDS AT KDRT WILL BECOME SE AT 10-15
MPH AFTER 17Z THEN BACK TO EASTERLY AFTER 01Z AT 5-10 KNOTS.
&&
.PREV DISCUSSION... /ISSUED 332 AM CST SAT DEC 5 2015/
SHORT TERM (TODAY THROUGH SUNDAY)...
COOL MORNINGS WITH PLEASANT AFTERNOON TEMPERATURES EXPECTED TODAY
AND SUNDAY WITH SOME CLOUDS MIXED IN ACROSS THE RIO GRANDE VALLEY.
TEMPERATURES WILL RETURN TO NEAR AND SLIGHTLY ABOVE NORMAL SUNDAY
WITH HIGHS REACHING INTO THE MID TO UPPER 60S.
WATER VAPOR AND RAP ANALYSIS DEPICT A WEAK SHORTWAVE RIDGE OVER
TEXAS AND THE GULF COASTAL WATERS THAT IS ALLOWING FOR WEAK
MOISTURE RETURN IN THE 925-700MB LAYER. THE MAIN WEAK MOISTURE
TONGUE IS CONFINED TO THE RIO GRANDE VALLEY AS IT POOLS AGAINST
THE SIERRA DEL BURRO RANGE. AS A RESULT...EXPECT LOW CLOUDS TO
DEVELOP THROUGH THE MORNING HOURS ACROSS THE RIO GRANDE VALLEY
THAT WILL SLOWLY BREAK UP THROUGH THE DAY. LOCATIONS EAST OF U.S.
HIGHWAY 83 WILL REMAIN MOSTLY SUNNY WITH ONLY HIGH CLOUDS
STREAMING OVERHEAD. AREAS SEEING MORE CLOUDS OUT WEST WILL NOT
WARM AS MUCH AS CENTRAL AND EAST LOCATIONS WITH A NICE REBOUND INTO
THE LOW TO MID 60S EXPECTED TODAY. MAVMOS ALONG WITH SUPPORT FROM
RAW MODEL SOUNDING GUIDANCE APPEARS TO BE THE BEST ROUTE FOR
MAXIMUM HIGHS TODAY. MIXING HEIGHTS WILL TOP OUT NEAR 2-2.2KFT
NEAR 9-10C THAT WILL SUPPORT THESE HIGHER VALUES VS. THE SLIGHTLY
COOLER MET/ECSMOS. DID TRIM 1F DEGREE OFF MAX HIGHS FOR KDRT
GIVEN THE CLOUD INTERFERENCE THROUGH AT LEAST THE LATE MORNING.
EXPECT A NEAR COPY FOR SUNDAY WITH SOME MORNING CLOUDS ACROSS THE
RIO GRANDE VALLEY AGAIN AND TEMPERATURES AREAWIDE LIKELY 1-3F
DEGREES WARMER IN THE AFTERNOON. SOME LOCATIONS ACROSS THE COASTAL
PLAINS AND NEAR KSAT COULD PUSH THE 70F DEGREE MARK. A WEAK
DRYLINE WILL SHIFT THROUGH ON SUNDAY USHERING IN DRIER AIR WITH
N/NW WINDS AND ONLY LIMITED MID-LEVEL CLOUDS. NO COLD AIR IS
ASSOCIATED WITH THIS BOUNDARY AND THUS WE WILL CONTINUE TO WARM
THROUGH THE AFTERNOON DESPITE THE NORTH WINDS.
LONG TERM (MONDAY THROUGH FRIDAY)...
NO HAZARDS APPEAR LIKELY THROUGH THE LONG TERM WITH PLEASANT AND
ABOVE NORMAL TEMPERATURES EXPECTED THROUGH AT LEAST THURSDAY. RAIN
CHANCES WILL INCREASE GOING INTO NEXT SATURDAY AHEAD OF A STRONGER
COLD FRONT AND MID-LVL SYSTEM.
FROM EARLY NEXT WEEK TO MID WEEK...THE REGION WILL REMAIN SOUTH OF
THE ACTIVE JET STREAM AND VOID OF AIRMASS CHANGES. SURFACE HIGH
PRESSURE WILL REMAIN OVER THE NORTHERN GULF THROUGH MID-WEEK AND
WEAK SOUTHWEST FLOW ALOFT. PWATS WILL BE IN THE 0.4"-0.8" RANGE
AS WEAK SOUTH SURFACE WINDS ATTEMPT TO BRING HIGHER MOISTURE TO
THE REGION. BY THURSDAY...A STRONGER SHORTWAVE TROUGH ACROSS THE
CENTRAL PLAINS WILL PUSH A WEAK FRONT NEAR THE HILL COUNTRY BUT
ONLY LIMITED RAIN CHANCES FOR THE COASTAL PLAINS ARE EXPECTED
WHERE PWATS WILL RECOVER TOWARDS 1.3".
A MORE POWERFUL SYSTEM WILL APPROACH THE BIG BEND LATE FRIDAY
INTO THE WEEKEND THAT MAY AID IN SOME SCATTERED SHOWERS AND STORMS.
THE BEST DYNAMICS AND FORCING SILL APPEAR TO BE NORTH AND EAST
WHERE THE BETTER RAIN CHANCES WILL BE. PWAT RECOVER STILL APPEARS
LOW TO MODEST AT BEST AND WILL ADVERTISE 20-30% FOR NOW AND WATCH
THE MODEL EVOLUTION FOR THIS TIME FRAME.
&&
.PRELIMINARY POINT TEMPS/POPS...
AUSTIN CAMP MABRY 65 42 67 40 66 / 0 0 0 0 0
AUSTIN BERGSTROM INTL AIRPORT 64 39 66 37 65 / 0 0 0 0 0
NEW BRAUNFELS MUNI AIRPORT 66 41 67 40 67 / 0 0 0 0 0
BURNET MUNI AIRPORT 63 41 63 37 64 / 0 0 0 0 0
DEL RIO INTL AIRPORT 63 42 66 41 66 / 0 0 0 0 0
GEORGETOWN MUNI AIRPORT 62 43 64 35 64 / 0 0 0 0 0
HONDO MUNI AIRPORT 65 40 68 38 66 / 0 0 0 0 0
SAN MARCOS MUNI AIRPORT 64 40 66 40 65 / 0 0 0 0 0
LA GRANGE - FAYETTE REGIONAL 65 43 67 42 66 / 0 0 0 0 0
SAN ANTONIO INTL AIRPORT 65 42 68 42 66 / 0 0 0 0 0
STINSON MUNI AIRPORT 66 43 69 42 67 / 0 0 0 0 0
&&
.EWX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
MESOSCALE/AVIATION...10
SYNOPTIC/GRIDS...ALLEN
AREA FORECAST DISCUSSION
NWS PUEBLO CO
1017 AM MST SAT DEC 5 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 458 AM MST SAT DEC 5 2015
AN UPPER LEVEL TROF WILL BE MOVING ACROSS THE STATE TODAY. THIS
SYSTEM WILL BRING SOME SNOW TO THE CONTDVD THRU THE DAY...WITH THE
BEST CHANCES BEING OVER THE CENTRAL MTNS. SNOW ACCUMULATIONS ALONG
THE CONTDVD WILL BE LIGHT...WITH MAYBE 2-3 INCHES OVR THE CENTRAL
MTNS. PCPN WILL SPREAD EASTWARD TODAY...WITH LIGHT SNOW
ACCUMULATIONS EXPECTED OVER THE EASTERN MTNS...MAINLY THIS
AFTERNOON. BY LATE MORNING A COLD FRONT WILL MOVE INTO EL PASO
COUNTY AND THEN CONTINUE SOUTHWARD THRU THE PLAINS THRU THE EARLY
AFTERNOON...BRINGING GUSTY NORTHERLY WINDS TO THE AREA. THE FORECAST
MODELS HAVE BEEN CONSISTENT IN BRINGING PCPN TO EL PASO AND TELLER
COUNTIES LATE THIS MORNING AND THIS AFTERNOON. THE NAM AND HRRR ALSO
SHOW THE POTENTIAL FOR SOME ISOLD PCPN ALONG THE I-25 CORRIDOR OVR
PUEBLO...HUERFANO AND WRN LAS ANIMAS COUNTIES. LOOKS LIKE LITTLE
CHANCE FOR PCPN OVR THE FAR SERN PLAINS. TEMPS WILL BE COOLER
TODAY...BUT HIGHS SHOULD GENERALLY STILL BE A LITTLE ABOVE AVERAGE.
THE UPR TROF MOVES OUT OF THE STATE IN THE EARLY EVENING HOURS...AND
BY LATE EVENING PCPN CHANCES SHOULD END WITH CLEARING SKIES.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 458 AM MST SAT DEC 5 2015
OVERALL...IT STILL APPEARS THAT A MILD AND RELATIVELY DRY METEOROLOGICAL
PATTERN SHOULD BE NOTED OVER THE MAJORITY OF THE FORECAST DISTRICT
DURING THE BALANCE OF THE LONGER TERM...ALTHOUGH INCREASING
PRECIPITATION CHANCES ARE ANTICIPATED BY LATER IN THE WEEK AS A
SYSTEM IMPACTS THE REGION.
MAIN METEOROLOGICAL ISSUES DURING THE LONGER TERM WILL BE
TEMPERATURES...THE POTENTIAL FOR GUSTY WINDS AT TIMES AND
POPS(ESPECIALLY BY LATER IN THE WEEK).
THE DRY UPPER RIDGING PATTERN OF SUNDAY WILL TRANSITION TO A DRY
ZONAL TO NORTHWESTERLY UPPER FLOW PATTERN FROM SUNDAY NIGHT INTO
AT LEAST WEDNESDAY EVENING.
THEN...AN UPPER SYSTEM APPROACHING THE FORECAST DISTRICT BY LATE
WEEK WILL BRING THE POTENTIAL FOR UNSETTLED METEOROLOGICAL
CONDITIONS BY LATER NEXT WEEK(ESPECIALLY OVER PORTIONS OF THE
CENTRAL AND WESTERN MOUNTAINS).
IN ADDITION...VARYING DEGREES OF EASTERN COLORADO SURFACE LEE-SIDE
TROUGHING IS ANTICIPATED FROM SUNDAY INTO FRIDAY WITH THE
POTENTIAL FOR A NORTHERLY SURGE MOVING ACROSS EASTERN SECTIONS
DURING FRIDAY EVENING/NIGHT.
THE HIGHEST POTENTIAL FOR STRONGER GRADIENT WINDS DURING THE
LONGER TERM SHOULD BE NOTED FROM THURSDAY INTO NEXT WEEKEND.
IN REGARDS TO TEMPERATURES...GENERALLY ABOVE SEASONAL EARLY TO
MID-DECEMBER TEMPERATURES ARE PROJECTED FROM SUNDAY INTO FRIDAY
WITH COOLER TEMPERATURES ANTICIPATED BY NEXT SATURDAY. AT THIS
TIME...IT APPEARS THAT THE WARMEST CONDITIONS DURING THE LONGER
TERM SHOULD BE REALIZED FROM MONDAY INTO WEDNESDAY...WITH COOLEST
READINGS EXPECTED BY FRIDAY AND ESPECIALLY NEXT SATURDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1005 AM MST SAT DEC 5 2015
A COOL FRONT WILL MOVE ACROSS KPUB AND KPUB AT THIS TIME. WINDS
WILL TAKE ON A NORTHERLY COMPONENT AND MAY BE A BIT GUSTY AT
TIMES. A FEW ISOLATED SHOWERS WILL ALSO BE POSSIBLE. WINDS WILL
BECOME LIGHT NORTHWESTERLY BY SUNSET. OVERALL...EXPECT VFR
CONDITIONS AT KPUB AND KCOS...BUT THERE MAY BE A VERY BRIEF PD OF
MVFR IF ANY HEAVY SNOW SHOWER DEVELOPS.
AT KALS...VFR CONDITIONS ARE ANTICIPATED.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AVIATION...HODANISH
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
149 PM CST SAT DEC 5 2015
.UPDATE...1037 AM CST
WE HAVE ENDED THE DENSE FOG ADVISORY FOR MOST AREAS NORTH OF I80
IN ILLINOIS THIS MORNING...AND THE REST OF THE AREA WILL LIKELY BE
ABLE TO END AT THE CURRENT EXPIRATION TIME AT NOON. CONDITIONS
HAVE CLEARED UP RATHER QUICKLY ACROSS NORTHERN
ILLINOIS...ESPECIALLY NORTH OF I-88 AS OF THIS WRITING. IT APPEARS
LIKELY THAT THE NORTHERN AND WESTERN EDGES OF THIS CLOUD/FOG DECK
WILL CONTINUE TO SLOWLY DISSIPATE THROUGH THE AFTERNOON. THIS
COULD RESULT IN MY NORTHWESTERN INDIANA COUNTIES AND EAST CENTRAL
ILLINOIS COUNTIES BEING IN THE LOW CLOUDS FOR MOST OF THE
DAY...SIMILAR TO YESTERDAY.
CONSIDERING SKIES ARE CLEARING QUICK NORTH...I HAVE RAISE HIGHS THIS
AFTERNOON...AS THE AIRMASS OVER THE AREA SHOULD SUPPORT MILD
CONDITIONS WELL INTO THE 40S OUTSIDE OF THE CLOUDY AREAS.
THEREFORE...THE WARMEST CONDITIONS...NEAR 50 LOOK TO BE NORTH AND IN
CHICAGO...WITH COOLER CONDITIONS...ONLY IN THE UPPER 30S TO LOW 40S
IN MY SOUTHEASTERN AREAS. I HAVE UPDATED THE FORECAST TO LEAN IN
THIS DIRECTION.
ITS POSSIBLE THAT SOME FOG AND LOW CLOUDS COULD RETURN TONIGHT...BUT
I WILL LOOK AT THIS POTENTIAL THIS AFTERNOON.
KJB
&&
.SHORT TERM...
312 AM CST
THROUGH SUNDAY NIGHT...
LOW STRATUS AND FOG THE PRIMARY FORECAST CONCERNS OVER THE NEXT
COUPLE DAYS. SURFACE HIGH PRESSURE IS CENTERED OVER THE UPPER OHIO
VALLEY EARLY THIS MORNING AND IS PROGGED TO BUILD TOWARDS THE
MID ATLANTIC COAST OVER THE WEEKEND. SATELLITE IMAGERY AND SURFACE
OBS SHOWS LOW STRATUS AND FOG BLANKETING THE EASTERN 2/3 OR SO OF
ILLINOIS AND PRACTICALLY ALL OF INDIANA. CLOUDS HAVE BEEN STEADILY
SPREADING NORTHWEST OVERNIGHT AND SHOULD BLANKET THE ENTIRE
FORECAST AREA THROUGH THE MORNING. THEREAFTER...THE ONLY MODEL
THAT WANTS TO HOLD ONTO THE CLOUD COVER THROUGH THE MAJORITY OF
THE DAY IS THE HRRR WHICH SEEMS FAIRLY REASONABLE GIVEN LACK OF
EROSION YESTERDAY. MOST OTHER MODELS BEGIN TO ERODE THE STRATUS BY
MIDDAY HOWEVER A RATHER IMPRESSIVE LOW LEVEL INVERSION COULD KEEP
THE LOW LEVEL MOISTURE TRAPPED THROUGH MUCH OF THE WEEKEND. 05Z
AMDAR SOUNDING OUT OF THE CHICAGO AREA SHOWED 980MB TEMP OF 0.3C
SHARPLY WARMING TO 9.0C AROUND 935MB. LATEST FORECAST GOES UNDER
THE ASSUMPTION THAT MOST OF THE CWA WILL REMAIN UNDER OVERCAST
SKIES AND HAVE ADJUSTED TEMPS DOWN QUITE A BIT FROM PREVIOUS
FORECASTS. FAR NORTH CENTRAL ILLINOIS WILL HAVE THE BEST CHANCE TO
SEE SOME EROSION ALONG THE EDGE OF THE STRATUS DECK BUT CONFIDENCE
IS LOW HOW THIS WILL PLAY OUT OR WHERE TO DRAW THE LINE. AS IS
TYPICAL WITH THESE SCENARIOS THERE IS LARGE BUST POTENTIAL...WITH
HIGHS ONLY IN THE UPPER 30S TO AROUND 40 ON THE COLD END UNDER
CLOUDS ALL DAY BUT IF SUNSHINE IS ABLE TO BREAK THROUGH...THOSE
VERY WARM TEMPS ALOFT WOULD SUPPORT TEMPERATURES QUICKLY SHOOTING
UP WITH HIGHS IN THE LOW 50S. OVERNIGHT...BOUNDARY LAYER FLOW
BACKS SLIGHTLY SO WOULD ANTICIPATE ANY LOW CIGS TO SPREAD BACK TO
ANY AREAS IN NORTH CENTRAL ILLINOIS THAT MIGHT ERODE ALONG THE
EDGE OF THE STRATUS...BUT CONFIDENCE IS FAIRLY LOW HOW THIS WILL
PLAY OUT.
SATURDAY NIGHT INTO SUNDAY...AN UPPER LEVEL WAVE WILL TRANSLATE
EAST ACROSS THE PLAINS REACHING THE OHIO VALLEY BY SUNDAY
EVENING. MID LEVEL HEIGHT FALLS IN ADVANCE OF THIS SYSTEM BEGIN TO
OVERSPREAD NORTHERN ILLINOIS SATURDAY NIGHT THOUGH THE BULK OF THE
FORCING STAYS SOUTH OF THE CWA DURING THE DAY SUNDAY. OUTSIDE OF
THE POSSIBLE CONTINUING LOW STRATUS...FAIRLY LITTLE MOISTURE IS
EXPECTED WITH THIS SYSTEM. MIGHT BE ABLE TO SQUEEZE OUT SOME
DRIZZLE SATURDAY NIGHT INTO EARLY SUNDAY BUT OTHERWISE CONFINED
POPS TO SOUTHWEST AREAS OF THE CWA AND ONLY SLIGHT CHC. LOW LEVEL
CLOUDS IF STILL AROUND EXPECTED TO FINALLY ERODE SUNDAY...HOWEVER
MID AND HIGH CLOUD COVER WILL BE INCREASING ACROSS THE AREA.
DEUBELBEISS
&&
.LONG TERM...
312 AM CST
MONDAY THROUGH FRIDAY...
UPPER PATTERN WILL BECOME ZONAL FOR THE UPCOMING WEEK WITH A
SERIES OF DISTURBANCES BRINGING PERIODIC CHANCES FOR PRECIP
PARTICULARLY THE LATTER HALF OF THE WEEK. TEMPERATURES SHOULD
REMAIN MILD THROUGH THE ENTIRE WEEK WITH A GRADUAL WARMING TREND
EXPECTED. TEMPERATURES ON MONDAY WILL MAX IN THE MID 40S ACROSS
THE FORECAST AREA AND LOW 50S ARE POSSIBLE BY THURSDAY AND FRIDAY.
BOTH THE ECMWF AND GFS ADVERTISE A SHORTWAVE TROUGH DROPPING
ACROSS UPPER MIDWEST/WESTERN GREAT LAKES WEDNESDAY NIGHT.
THEN...WILL HAVE TO KEEP A CLOSE EYE ON A POTENTIALLY MORE POTENT
SYSTEM LATE IN THE WEEK...THOUGH MODELS CONTINUE TO BOUNCE AROUND
ON THE DETAILS AS THEY STRUGGLE TO HANDLE THE PHASING OF UPPER
LEVEL ENERGY.
DEUBELBEISS
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 20Z...
* VFR CONDS ARE EXPECTED TO QUICKLY REDUCE TO IFR SHORTLY AFT 02Z
AND LIKELY LASTING ALL NIGHT...POSSIBLY DIPPING TO VLIFR.
* SOUTH TO SOUTHWEST WINDS BETWEEN 4-8KT.
BEACHLER
//DISCUSSION...UPDATED 18Z...
VISIBLE SATELLITE IMAGERY CONTINUES TO SHOW STEADY EROSION OF THE
STRATUS LAYER THAT HAS BLANKETED NORTHERN IL/NORTHWEST IN
AIRFIELDS THIS MORNING...UNFORTUNATELY IT APPEARS DUE TO THE LACK
OF MIXING DRIER AIR TO THE SURFACE THAT THE STRATUS AND FOG WILL
REDEVELOP AGAIN TONIGHT AND PERSIST THROUGH SUNDAY MORNING.
CURRENT HI-RES GUIDANCE CONTINUES TO SUGGEST THAT AROUND 00-02Z
SHALLOW STRATUS AROUND 500-800FT AGL WILL REDEVELOP AND THEN TREND
DOWN TOWARDS 400-500FT AGL LATE TONIGHT THROUGH DAYBREAK SUNDAY.
HAVE REFLECTED THIS IN THE CURRENT TAF...BUT THE UNCERTAINTY
REMAINS WITH HOW LOW VSBYS WILL GO AS SOME THIN CIRRUS IS NOTED TO
LIFT NORTHEAST ACROSS NORTHERN IL OVERNIGHT AND COULD LIMIT THE
DEVELOPMENT OF FOG.
BEACHLER
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
* MEDIUM/HIGH CONFIDENCE IN CIGS QUICKLY LOWERING...LOW CONFIDENCE
IN PRECISE TIMING OF IFR/LIFR CIGS.
* HIGH CONFIDENCE IN WIND DIR/SPEED.
BEACHLER
//OUTLOOK FOR ORD/MDW FOR 00Z MONDAY-12Z SATURDAY...UPDATED 12Z...
SUNDAY NIGHT THROUGH TUESDAY...PRIMARILY VFR. SMALL DAY TO DAY
CHANCE OF IFR CIGS/FOG DURING LATE NIGHTS/MORNINGS.
WEDNESDAY...SLIGHT CHANCE -RA/MVFR.
THURSDAY...VFR/MVFR CIGS.
FRIDAY...SLIGHT CHANCE -RA AND MVFR/IFR.
RATZER
&&
.MARINE...
250 AM CST
HIGH PRESSURE MOVING EAST ACROSS THE UPPER OHIO VALLEY TO THE MID
ATLANTIC REGION TODAY...AND LOW PRESSURE MOVING FROM MANITOBA TO
HUDSON BAY...WILL ALLOW SOUTH-SOUTHWEST WINDS TO PERSIST ACROSS
LAKE MICHIGAN. THE GRADIENT WILL TIGHTEN DURING THE DAY IN
RESPONSE TO PRESSURE FALLS ASSOCIATED WITH THE CANADIAN LOW...
WITH SOUTHERLY WINDS INCREASING INTO THE 30 KT RANGE THIS
AFTERNOON INTO TONIGHT OVER THE NORTHERN PART OF THE LAKE. THE
GRADIENT WILL THEN WEAKEN SUNDAY AS A WEAK COLD FRONT SLIDES
SOUTHEAST ACROSS THE LAKE...WITH WINDS SHIFTING TO THE WEST-
NORTHWEST. WEAK HIGH PRESSURE WILL BUILD IN BEHIND THE FRONT
SUNDAY NIGHT INTO MONDAY...BEFORE THE PATTERN REVERTS TO LOW
PRESSURE LIFTING NORTHEAST ACROSS CANADA AND NORTH OF THE LAKES
AND BRINGS A RETURN TO SOUTH-SOUTHWEST WINDS INTO EARLY NEXT WEEK.
RATZER
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
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AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1204 PM CST SAT DEC 5 2015
.UPDATE...
1037 AM CST
WE HAVE ENDED THE DENSE FOG ADVISORY FOR MOST AREAS NORTH OF I80
IN ILLINOIS THIS MORNING...AND THE REST OF THE AREA WILL LIKELY BE
ABLE TO END AT THE CURRENT EXPIRATION TIME AT NOON. CONDITIONS
HAVE CLEARED UP RATHER QUICKLY ACROSS NORTHERN
ILLINOIS...ESPECIALLY NORTH OF I-88 AS OF THIS WRITING. IT APPEARS
LIKELY THAT THE NORTHERN AND WESTERN EDGES OF THIS CLOUD/FOG DECK
WILL CONTINUE TO SLOWLY DISSIPATE THROUGH THE AFTERNOON. THIS
COULD RESULT IN MY NORTHWESTERN INDIANA COUNTIES AND EAST CENTRAL
ILLINOIS COUNTIES BEING IN THE LOW CLOUDS FOR MOST OF THE
DAY...SIMILAR TO YESTERDAY.
CONSIDERING SKIES ARE CLEARING QUICK NORTH...I HAVE RAISE HIGHS THIS
AFTERNOON...AS THE AIRMASS OVER THE AREA SHOULD SUPPORT MILD
CONDITIONS WELL INTO THE 40S OUTSIDE OF THE CLOUDY AREAS.
THEREFORE...THE WARMEST CONDITIONS...NEAR 50 LOOK TO BE NORTH AND IN
CHICAGO...WITH COOLER CONDITIONS...ONLY IN THE UPPER 30S TO LOW 40S
IN MY SOUTHEASTERN AREAS. I HAVE UPDATED THE FORECAST TO LEAN IN
THIS DIRECTION.
ITS POSSIBLE THAT SOME FOG AND LOW CLOUDS COULD RETURN TONIGHT...BUT
I WILL LOOK AT THIS POTENTIAL THIS AFTERNOON.
KJB
&&
.SHORT TERM...
312 AM CST
THROUGH SUNDAY NIGHT...
LOW STRATUS AND FOG THE PRIMARY FORECAST CONCERNS OVER THE NEXT
COUPLE DAYS. SURFACE HIGH PRESSURE IS CENTERED OVER THE UPPER OHIO
VALLEY EARLY THIS MORNING AND IS PROGGED TO BUILD TOWARDS THE
MID ATLANTIC COAST OVER THE WEEKEND. SATELLITE IMAGERY AND SURFACE
OBS SHOWS LOW STRATUS AND FOG BLANKETING THE EASTERN 2/3 OR SO OF
ILLINOIS AND PRACTICALLY ALL OF INDIANA. CLOUDS HAVE BEEN STEADILY
SPREADING NORTHWEST OVERNIGHT AND SHOULD BLANKET THE ENTIRE
FORECAST AREA THROUGH THE MORNING. THEREAFTER...THE ONLY MODEL
THAT WANTS TO HOLD ONTO THE CLOUD COVER THROUGH THE MAJORITY OF
THE DAY IS THE HRRR WHICH SEEMS FAIRLY REASONABLE GIVEN LACK OF
EROSION YESTERDAY. MOST OTHER MODELS BEGIN TO ERODE THE STRATUS BY
MIDDAY HOWEVER A RATHER IMPRESSIVE LOW LEVEL INVERSION COULD KEEP
THE LOW LEVEL MOISTURE TRAPPED THROUGH MUCH OF THE WEEKEND. 05Z
AMDAR SOUNDING OUT OF THE CHICAGO AREA SHOWED 980MB TEMP OF 0.3C
SHARPLY WARMING TO 9.0C AROUND 935MB. LATEST FORECAST GOES UNDER
THE ASSUMPTION THAT MOST OF THE CWA WILL REMAIN UNDER OVERCAST
SKIES AND HAVE ADJUSTED TEMPS DOWN QUITE A BIT FROM PREVIOUS
FORECASTS. FAR NORTH CENTRAL ILLINOIS WILL HAVE THE BEST CHANCE TO
SEE SOME EROSION ALONG THE EDGE OF THE STRATUS DECK BUT CONFIDENCE
IS LOW HOW THIS WILL PLAY OUT OR WHERE TO DRAW THE LINE. AS IS
TYPICAL WITH THESE SCENARIOS THERE IS LARGE BUST POTENTIAL...WITH
HIGHS ONLY IN THE UPPER 30S TO AROUND 40 ON THE COLD END UNDER
CLOUDS ALL DAY BUT IF SUNSHINE IS ABLE TO BREAK THROUGH...THOSE
VERY WARM TEMPS ALOFT WOULD SUPPORT TEMPERATURES QUICKLY SHOOTING
UP WITH HIGHS IN THE LOW 50S. OVERNIGHT...BOUNDARY LAYER FLOW
BACKS SLIGHTLY SO WOULD ANTICIPATE ANY LOW CIGS TO SPREAD BACK TO
ANY AREAS IN NORTH CENTRAL ILLINOIS THAT MIGHT ERODE ALONG THE
EDGE OF THE STRATUS...BUT CONFIDENCE IS FAIRLY LOW HOW THIS WILL
PLAY OUT.
SATURDAY NIGHT INTO SUNDAY...AN UPPER LEVEL WAVE WILL TRANSLATE
EAST ACROSS THE PLAINS REACHING THE OHIO VALLEY BY SUNDAY
EVENING. MID LEVEL HEIGHT FALLS IN ADVANCE OF THIS SYSTEM BEGIN TO
OVERSPREAD NORTHERN ILLINOIS SATURDAY NIGHT THOUGH THE BULK OF THE
FORCING STAYS SOUTH OF THE CWA DURING THE DAY SUNDAY. OUTSIDE OF
THE POSSIBLE CONTINUING LOW STRATUS...FAIRLY LITTLE MOISTURE IS
EXPECTED WITH THIS SYSTEM. MIGHT BE ABLE TO SQUEEZE OUT SOME
DRIZZLE SATURDAY NIGHT INTO EARLY SUNDAY BUT OTHERWISE CONFINED
POPS TO SOUTHWEST AREAS OF THE CWA AND ONLY SLIGHT CHC. LOW LEVEL
CLOUDS IF STILL AROUND EXPECTED TO FINALLY ERODE SUNDAY...HOWEVER
MID AND HIGH CLOUD COVER WILL BE INCREASING ACROSS THE AREA.
DEUBELBEISS
&&
.LONG TERM...
312 AM CST
MONDAY THROUGH FRIDAY...
UPPER PATTERN WILL BECOME ZONAL FOR THE UPCOMING WEEK WITH A
SERIES OF DISTURBANCES BRINGING PERIODIC CHANCES FOR PRECIP
PARTICULARLY THE LATTER HALF OF THE WEEK. TEMPERATURES SHOULD
REMAIN MILD THROUGH THE ENTIRE WEEK WITH A GRADUAL WARMING TREND
EXPECTED. TEMPERATURES ON MONDAY WILL MAX IN THE MID 40S ACROSS
THE FORECAST AREA AND LOW 50S ARE POSSIBLE BY THURSDAY AND FRIDAY.
BOTH THE ECMWF AND GFS ADVERTISE A SHORTWAVE TROUGH DROPPING
ACROSS UPPER MIDWEST/WESTERN GREAT LAKES WEDNESDAY NIGHT.
THEN...WILL HAVE TO KEEP A CLOSE EYE ON A POTENTIALLY MORE POTENT
SYSTEM LATE IN THE WEEK...THOUGH MODELS CONTINUE TO BOUNCE AROUND
ON THE DETAILS AS THEY STRUGGLE TO HANDLE THE PHASING OF UPPER
LEVEL ENERGY.
DEUBELBEISS
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 18Z...
* VFR CONDS ARE EXPECTED TO QUICKLY REDUCE TO IFR SHORTLY AFT 02Z
AND LIKELY LASTING ALL NIGHT...POSSIBLY DIPPING TO VLIFR.
* SOUTH TO SOUTHWEST WINDS BETWEEN 4-8KT.
BEACHLER
//DISCUSSION...UPDATED 18Z...
VISIBLE SATELLITE IMAGERY CONTINUES TO SHOW STEADY EROSION OF THE
STRATUS LAYER THAT HAS BLANKETED NORTHERN IL/NORTHWEST IN
AIRFIELDS THIS MORNING...UNFORTUNATELY IT APPEARS DUE TO THE LACK
OF MIXING DRIER AIR TO THE SURFACE THAT THE STRATUS AND FOG WILL
REDEVELOP AGAIN TONIGHT AND PERSIST THROUGH SUNDAY MORNING.
CURRENT HI-RES GUIDANCE CONTINUES TO SUGGEST THAT AROUND 00-02Z
SHALLOW STRATUS AROUND 500-800FT AGL WILL REDEVELOP AND THEN TREND
DOWN TOWARDS 400-500FT AGL LATE TONIGHT THROUGH DAYBREAK SUNDAY.
HAVE REFLECTED THIS IN THE CURRENT TAF...BUT THE UNCERTAINTY
REMAINS WITH HOW LOW VSBYS WILL GO AS SOME THIN CIRRUS IS NOTED TO
LIFT NORTHEAST ACROSS NORTHERN IL OVERNIGHT AND COULD LIMIT THE
DEVELOPMENT OF FOG.
BEACHLER
//ORD AND MDW CONFIDENCE...UPDATED 18Z...
* MEDIUM/HIGH CONFIDENCE IN CIGS QUICKLY LOWERING...LOW CONFIDENCE
IN PRECISE TIMING OF IFR/LIFR CIGS.
* HIGH CONFIDENCE IN WIND DIR/SPEED.
BEACHLER
//OUTLOOK FOR ORD/MDW FOR 00Z MONDAY-12Z SATURDAY...UPDATED 12Z...
SUNDAY NIGHT THROUGH TUESDAY...PRIMARILY VFR. SMALL DAY TO DAY
CHANCE OF IFR CIGS/FOG DURING LATE NIGHTS/MORNINGS.
WEDNESDAY...SLIGHT CHANCE -RA/MVFR.
THURSDAY...VFR/MVFR CIGS.
FRIDAY...SLIGHT CHANCE -RA AND MVFR/IFR.
RATZER
&&
.MARINE...
250 AM CST
HIGH PRESSURE MOVING EAST ACROSS THE UPPER OHIO VALLEY TO THE MID
ATLANTIC REGION TODAY...AND LOW PRESSURE MOVING FROM MANITOBA TO
HUDSON BAY...WILL ALLOW SOUTH-SOUTHWEST WINDS TO PERSIST ACROSS
LAKE MICHIGAN. THE GRADIENT WILL TIGHTEN DURING THE DAY IN
RESPONSE TO PRESSURE FALLS ASSOCIATED WITH THE CANADIAN LOW...
WITH SOUTHERLY WINDS INCREASING INTO THE 30 KT RANGE THIS
AFTERNOON INTO TONIGHT OVER THE NORTHERN PART OF THE LAKE. THE
GRADIENT WILL THEN WEAKEN SUNDAY AS A WEAK COLD FRONT SLIDES
SOUTHEAST ACROSS THE LAKE...WITH WINDS SHIFTING TO THE WEST-
NORTHWEST. WEAK HIGH PRESSURE WILL BUILD IN BEHIND THE FRONT
SUNDAY NIGHT INTO MONDAY...BEFORE THE PATTERN REVERTS TO LOW
PRESSURE LIFTING NORTHEAST ACROSS CANADA AND NORTH OF THE LAKES
AND BRINGS A RETURN TO SOUTH-SOUTHWEST WINDS INTO EARLY NEXT WEEK.
RATZER
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...DENSE FOG ADVISORY...ILZ019-ILZ021-ILZ023-ILZ032-ILZ033-ILZ039
UNTIL NOON SATURDAY.
IN...DENSE FOG ADVISORY...INZ001-INZ002-INZ010-INZ011-INZ019 UNTIL
NOON SATURDAY.
LM...NONE.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
National Weather Service Lincoln IL
1154 AM CST SAT DEC 5 2015
.UPDATE...
ISSUED AT 1103 AM CST SAT DEC 5 2015
Surface ridge moving off to the east, and the winds continue with
a southerly direction across Central Illinois. Low level moisture
trapped by the significant inversion off the surface has resulted
in another foggy day. Eastern half of the state is slow to improve
yet again this morning, with the I-55 corridor a bit patchy still
between Bloomington and Springfield. Some minor adjustments to the
grids for the fog, and dropping the max temps a little in the east
with the lack of sunshine.
&&
.SHORT TERM...(Today)
ISSUED AT 243 AM CST SAT DEC 5 2015
Dense fog continues to expand north and west early this morning as
the boundary layer flow remains out of the east and southeast. Have
expanded the Dense Fog advisory to include all counties except
Schuyler until Noon. Latest few runs of the HRRR suggest the fog
will edge west to Schuyler county just after 12z and then begin to
dissipate after sunrise. High pressure centered over Ohio will inch
slowly away from the area with the ridge axis forecast to extend
west into our area through much of the day. Forecast soundings
showing a very shallow moist layer at the surface trapped underneath
a strong low level inversion thru the day with our west and
southwest counties seeing the sun first with our eastern counties
not seeing any significant breaks until this afternoon, if then.
For what is usually a recipe for a big temperature bust, will use
continuity with respect to forecast highs this afternoon with a
very similar setup to what we experienced yesterday. Based off
that reasoning, will go fairly close to the highs obtained
yesterday afternoon, especially across the east where readings in
some areas didn`t get out of the 30s. Don`t have anything quite
that cool today as RUC soundings even in our far east were showing
several hours where we could see a little sunshine, unlike the
latest HRRR run which was showing the stratus and low visibilities
holding across our east throughout the afternoon. Our warmest
readings once again will be in the west where the mercury should
top out in the lower 50s, while roughly along and east of the I-55
corridor, afternoon highs will be mostly in the 40s, with a few
locations over east central IL just getting to 40 degree later
this afternoon.
.LONG TERM...(Tonight through Friday)
ISSUED AT 243 AM CST SAT DEC 5 2015
Low level inversion does not appear to be going away until Sunday,
when a shortwave currently located over Idaho and Utah arrives. SREF
probability guidance indicates the fog is likely to expand westward
once again this evening and cover most areas north of I-70. Would
not be surprised if another fog advisory is needed, but will wait to
see how much conditions can improve this afternoon first.
Aforementioned upper wave will close off as it crosses Illinois
Sunday afternoon. Have increased PoP`s to about 30% west of a Peoria
to Springfield line, mostly on the back side of the low, and
introduced 30% PoP`s across the southeast quarter of the forecast
area for evening as the low shifts into Indiana.
Remainder of the forecast period will be fairly mild for this time
of year, as the general upper flow remains of Pacific origin. Some
questions exist for late week, as one upper wave in particular digs
as it crosses the Dakotas. The ECMWF is more aggressive with this
digging and draws some colder air aloft southward from Manitoba,
producing a slower and more robust surface low/front Thursday night.
The GFS is much weaker and basically has a dry frontal passage.
Leaned a bit more toward the slower solution for now, but did not
make any significant changes to the initialized forecast grids due
to the uncertainty.
&&
.AVIATION...(For the 18Z TAFS through 18Z Sunday afternoon)
ISSUED AT 1138 AM CST SAT DEC 5 2015
Almost a total repeat of yesterday...Fog in the eastern half of
Illinois keeping CMI in VLIFR, DEC and BMI improving to LIFR, but
on the edge. At this point, SPI and PIA remain in VFR, and SPI may
end up seeing some patchy fog, but doubtful it will become
predominate or even enough to warrant a tempo. South/southeasterly
winds through the overnight, becoming more southerly, with the
ridge axis out to the east. Overnight, expect much of the same,
with the western terminals most likely to see breaks in the fog
just after dawn. But for now, do not see enough of a response with
the dewpoints to warrant tempos better than 1/2sm vis, at least
just before dawn. Will amend if the xover temps drop a few
degrees.
&&
.ILX Watches/Warnings/Advisories...
Dense Fog Advisory until noon CST today for ILZ038-042>046-
052>057-061>063-066>068-071>073.
&&
$$
UPDATE...HJS
SHORT TERM...Smith
LONG TERM...Geelhart
AVIATION...HJS
AREA FORECAST DISCUSSION
National Weather Service Lincoln IL
1109 AM CST SAT DEC 5 2015
.UPDATE...
ISSUED AT 1103 AM CST SAT DEC 5 2015
Surface ridge moving off to the east, and the winds continue with
a southerly direction across Central Illinois. Low level moisture
trapped by the significant inversion off the surface has resulted
in another foggy day. Eastern half of the state is slow to improve
yet again this morning, with the I-55 corridor a bit patchy still
between Bloomington and Springfield. Some minor adjustments to the
grids for the fog, and dropping the max temps a little in the east
with the lack of sunshine.
&&
.SHORT TERM...(Today)
ISSUED AT 243 AM CST SAT DEC 5 2015
Dense fog continues to expand north and west early this morning as
the boundary layer flow remains out of the east and southeast. Have
expanded the Dense Fog advisory to include all counties except
Schuyler until Noon. Latest few runs of the HRRR suggest the fog
will edge west to Schuyler county just after 12z and then begin to
dissipate after sunrise. High pressure centered over Ohio will inch
slowly away from the area with the ridge axis forecast to extend
west into our area through much of the day. Forecast soundings
showing a very shallow moist layer at the surface trapped underneath
a strong low level inversion thru the day with our west and
southwest counties seeing the sun first with our eastern counties
not seeing any significant breaks until this afternoon, if then.
For what is usually a recipe for a big temperature bust, will use
continuity with respect to forecast highs this afternoon with a
very similar setup to what we experienced yesterday. Based off
that reasoning, will go fairly close to the highs obtained
yesterday afternoon, especially across the east where readings in
some areas didn`t get out of the 30s. Don`t have anything quite
that cool today as RUC soundings even in our far east were showing
several hours where we could see a little sunshine, unlike the
latest HRRR run which was showing the stratus and low visibilities
holding across our east throughout the afternoon. Our warmest
readings once again will be in the west where the mercury should
top out in the lower 50s, while roughly along and east of the I-55
corridor, afternoon highs will be mostly in the 40s, with a few
locations over east central IL just getting to 40 degree later
this afternoon.
.LONG TERM...(Tonight through Friday)
ISSUED AT 243 AM CST SAT DEC 5 2015
Low level inversion does not appear to be going away until Sunday,
when a shortwave currently located over Idaho and Utah arrives. SREF
probability guidance indicates the fog is likely to expand westward
once again this evening and cover most areas north of I-70. Would
not be surprised if another fog advisory is needed, but will wait to
see how much conditions can improve this afternoon first.
Aforementioned upper wave will close off as it crosses Illinois
Sunday afternoon. Have increased PoP`s to about 30% west of a Peoria
to Springfield line, mostly on the back side of the low, and
introduced 30% PoP`s across the southeast quarter of the forecast
area for evening as the low shifts into Indiana.
Remainder of the forecast period will be fairly mild for this time
of year, as the general upper flow remains of Pacific origin. Some
questions exist for late week, as one upper wave in particular digs
as it crosses the Dakotas. The ECMWF is more aggressive with this
digging and draws some colder air aloft southward from Manitoba,
producing a slower and more robust surface low/front Thursday night.
The GFS is much weaker and basically has a dry frontal passage.
Leaned a bit more toward the slower solution for now, but did not
make any significant changes to the initialized forecast grids due
to the uncertainty.
&&
.AVIATION...(For the 12Z TAFS through 12Z Sunday morning)
ISSUED AT 505 AM CST SAT DEC 5 2015
IFR TO VLIFR conditions are expected thru the morning hours before
a gradual improvement this afternoon, especially across our
western TAF sites. We have seen a temporary improvement in cigs
and vsbys at BMI and SPI but based on satellite and surface obs
to our east and south, it looks as if the cigs and vsbys will
come down again at both sites in the next hour or two. Forecast
soundings not offering much hope for any significant break in the
cigs late this morning into this afternoon with PIA and SPI seeing
the best chance for cigs to break for a time. Little change in the
air mass is expected as we head into the overnight hours with
the threat for fog and low cigs to redevelop again and hold into
the morning hours of Sunday. Surface winds will remain a non-
factor thru tonight with a south to southeast wind at 7 to
12 kts today, and from 5 to 10 kts tonight.
&&
.ILX Watches/Warnings/Advisories...
Dense Fog Advisory until noon CST today for ILZ038-042>046-
052>057-061>063-066>068-071>073.
&&
$$
UPDATE...HJS
SHORT TERM...Smith
LONG TERM...Geelhart
AVIATION...Smith
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1038 AM CST SAT DEC 5 2015
.UPDATE...
1037 AM CST
WE HAVE ENDED THE DENSE FOG ADVISORY FOR MOST AREAS NORTH OF I80
IN ILLINOIS THIS MORNING...AND THE REST OF THE AREA WILL LIKELY BE
ABLE TO END AT THE CURRENT EXPIRATION TIME AT NOON. CONDITIONS
HAVE CLEARED UP RATHER QUICKLY ACROSS NORTHERN
ILLINOIS...ESPECIALLY NORTH OF I-88 AS OF THIS WRITING. IT APPEARS
LIKELY THAT THE NORTHERN AND WESTERN EDGES OF THIS CLOUD/FOG DECK
WILL CONTINUE TO SLOWLY DISSIPATE THROUGH THE AFTERNOON. THIS
COULD RESULT IN MY NORTHWESTERN INDIANA COUNTIES AND EAST CENTRAL
ILLINOIS COUNTIES BEING IN THE LOW CLOUDS FOR MOST OF THE
DAY...SIMILAR TO YESTERDAY.
CONSIDERING SKIES ARE CLEARING QUICK NORTH...I HAVE RAISE HIGHS THIS
AFTERNOON...AS THE AIRMASS OVER THE AREA SHOULD SUPPORT MILD
CONDITIONS WELL INTO THE 40S OUTSIDE OF THE CLOUDY AREAS.
THEREFORE...THE WARMEST CONDITIONS...NEAR 50 LOOK TO BE NORTH AND IN
CHICAGO...WITH COOLER CONDITIONS...ONLY IN THE UPPER 30S TO LOW 40S
IN MY SOUTHEASTERN AREAS. I HAVE UPDATED THE FORECAST TO LEAN IN
THIS DIRECTION.
ITS POSSIBLE THAT SOME FOG AND LOW CLOUDS COULD RETURN TONIGHT...BUT
I WILL LOOK AT THIS POTENTIAL THIS AFTERNOON.
KJB
&&
.SHORT TERM...
312 AM CST
THROUGH SUNDAY NIGHT...
LOW STRATUS AND FOG THE PRIMARY FORECAST CONCERNS OVER THE NEXT
COUPLE DAYS. SURFACE HIGH PRESSURE IS CENTERED OVER THE UPPER OHIO
VALLEY EARLY THIS MORNING AND IS PROGGED TO BUILD TOWARDS THE
MID ATLANTIC COAST OVER THE WEEKEND. SATELLITE IMAGERY AND SURFACE
OBS SHOWS LOW STRATUS AND FOG BLANKETING THE EASTERN 2/3 OR SO OF
ILLINOIS AND PRACTICALLY ALL OF INDIANA. CLOUDS HAVE BEEN STEADILY
SPREADING NORTHWEST OVERNIGHT AND SHOULD BLANKET THE ENTIRE
FORECAST AREA THROUGH THE MORNING. THEREAFTER...THE ONLY MODEL
THAT WANTS TO HOLD ONTO THE CLOUD COVER THROUGH THE MAJORITY OF
THE DAY IS THE HRRR WHICH SEEMS FAIRLY REASONABLE GIVEN LACK OF
EROSION YESTERDAY. MOST OTHER MODELS BEGIN TO ERODE THE STRATUS BY
MIDDAY HOWEVER A RATHER IMPRESSIVE LOW LEVEL INVERSION COULD KEEP
THE LOW LEVEL MOISTURE TRAPPED THROUGH MUCH OF THE WEEKEND. 05Z
AMDAR SOUNDING OUT OF THE CHICAGO AREA SHOWED 980MB TEMP OF 0.3C
SHARPLY WARMING TO 9.0C AROUND 935MB. LATEST FORECAST GOES UNDER
THE ASSUMPTION THAT MOST OF THE CWA WILL REMAIN UNDER OVERCAST
SKIES AND HAVE ADJUSTED TEMPS DOWN QUITE A BIT FROM PREVIOUS
FORECASTS. FAR NORTH CENTRAL ILLINOIS WILL HAVE THE BEST CHANCE TO
SEE SOME EROSION ALONG THE EDGE OF THE STRATUS DECK BUT CONFIDENCE
IS LOW HOW THIS WILL PLAY OUT OR WHERE TO DRAW THE LINE. AS IS
TYPICAL WITH THESE SCENARIOS THERE IS LARGE BUST POTENTIAL...WITH
HIGHS ONLY IN THE UPPER 30S TO AROUND 40 ON THE COLD END UNDER
CLOUDS ALL DAY BUT IF SUNSHINE IS ABLE TO BREAK THROUGH...THOSE
VERY WARM TEMPS ALOFT WOULD SUPPORT TEMPERATURES QUICKLY SHOOTING
UP WITH HIGHS IN THE LOW 50S. OVERNIGHT...BOUNDARY LAYER FLOW
BACKS SLIGHTLY SO WOULD ANTICIPATE ANY LOW CIGS TO SPREAD BACK TO
ANY AREAS IN NORTH CENTRAL ILLINOIS THAT MIGHT ERODE ALONG THE
EDGE OF THE STRATUS...BUT CONFIDENCE IS FAIRLY LOW HOW THIS WILL
PLAY OUT.
SATURDAY NIGHT INTO SUNDAY...AN UPPER LEVEL WAVE WILL TRANSLATE
EAST ACROSS THE PLAINS REACHING THE OHIO VALLEY BY SUNDAY
EVENING. MID LEVEL HEIGHT FALLS IN ADVANCE OF THIS SYSTEM BEGIN TO
OVERSPREAD NORTHERN ILLINOIS SATURDAY NIGHT THOUGH THE BULK OF THE
FORCING STAYS SOUTH OF THE CWA DURING THE DAY SUNDAY. OUTSIDE OF
THE POSSIBLE CONTINUING LOW STRATUS...FAIRLY LITTLE MOISTURE IS
EXPECTED WITH THIS SYSTEM. MIGHT BE ABLE TO SQUEEZE OUT SOME
DRIZZLE SATURDAY NIGHT INTO EARLY SUNDAY BUT OTHERWISE CONFINED
POPS TO SOUTHWEST AREAS OF THE CWA AND ONLY SLIGHT CHC. LOW LEVEL
CLOUDS IF STILL AROUND EXPECTED TO FINALLY ERODE SUNDAY...HOWEVER
MID AND HIGH CLOUD COVER WILL BE INCREASING ACROSS THE AREA.
DEUBELBEISS
&&
.LONG TERM...
312 AM CST
MONDAY THROUGH FRIDAY...
UPPER PATTERN WILL BECOME ZONAL FOR THE UPCOMING WEEK WITH A
SERIES OF DISTURBANCES BRINGING PERIODIC CHANCES FOR PRECIP
PARTICULARLY THE LATTER HALF OF THE WEEK. TEMPERATURES SHOULD
REMAIN MILD THROUGH THE ENTIRE WEEK WITH A GRADUAL WARMING TREND
EXPECTED. TEMPERATURES ON MONDAY WILL MAX IN THE MID 40S ACROSS
THE FORECAST AREA AND LOW 50S ARE POSSIBLE BY THURSDAY AND FRIDAY.
BOTH THE ECMWF AND GFS ADVERTISE A SHORTWAVE TROUGH DROPPING
ACROSS UPPER MIDWEST/WESTERN GREAT LAKES WEDNESDAY NIGHT.
THEN...WILL HAVE TO KEEP A CLOSE EYE ON A POTENTIALLY MORE POTENT
SYSTEM LATE IN THE WEEK...THOUGH MODELS CONTINUE TO BOUNCE AROUND
ON THE DETAILS AS THEY STRUGGLE TO HANDLE THE PHASING OF UPPER
LEVEL ENERGY.
DEUBELBEISS
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 16Z...
* PATCHY IFR CIG/VIS IN STRATUS/FOG QUICKLY LIFTING TO VFR.
* POTENTIAL FOR REDEVELOPMENT OR LOWERING OF IFR/LIFR STRATUS/FOG
AGAIN TONIGHT.
RATZER/BEACHLER
//DISCUSSION...UPDATED 12Z...
STRATUS/FOG WHICH SPREAD ACROSS TERMINALS OVERNIGHT WILL REMAIN
THIS MORNING...WITH LIFR/VLIFR CONDITIONS GRADUALLY IMPROVING TO
IFR MID/LATE MORNING. WOULD EXPECT SOME EROSION AROUND THE EDGES
OF THE STRATUS DECK FROM MID-MORNING ON...THOUGH DEGREE OF
CLEARING LIKELY TO BE LIMITED THE FARTHER SOUTHEAST ONE GOES. IT
IS POSSIBLE SOME CLEARING EVEN TO VFR WILL OCCUR BY EARLY
AFTERNOON...MOST LIKELY AT RFD NEAR THE EDGE OF THE CLOUD DECK.
EVEN IF CIGS LINGER...WILL LIKELY SEE A DIURNAL RISE TO CIGS AND A
SIGNIFICANT IMPROVEMENT IN VIS. TOUGH QUESTION IS WHAT OCCURS
TONIGHT...AS CLEARING WOULD LIKELY SET THE STAGE FOR SOME
NORTHWARD REDEVELOPMENT SIMILAR TO LAST NIGHT...AND IF A CEILING
LINGERS LIKELY A DIURNAL LOWERING OF VIS/CIG. THUS WHILE GENERAL
TREND OF FORECAST IS FAIRLY GOOD CONFIDENCE...SPECIFIC DETAILS IN
TIMING AND EXACT CIG HEIGHTS/VIS REMAIN RATHER LOW.
WINDS WILL REMAIN GENERALLY SOUTHERLY...BETWEEN ABOUT 200-170 DEG
AND 10 KTS OR LESS.
RATZER
//ORD AND MDW CONFIDENCE...UPDATED 14Z...
* HIGH IN CURRENT CONDITIONS IMPROVEMENT.
* LOW IN TIMING IMPROVEMENT TODAY...AND TRENDS TONIGHT.
RATZER/BEACHLER
//OUTLOOK FOR ORD/MDW FOR 00Z MONDAY-12Z SATURDAY...UPDATED 12Z...
SUNDAY NIGHT THROUGH TUESDAY...PRIMARILY VFR. SMALL DAY TO DAY
CHANCE OF IFR CIGS/FOG DURING LATE NIGHTS/MORNINGS.
WEDNESDAY...SLIGHT CHANCE -RA/MVFR.
THURSDAY...VFR/MVFR CIGS.
FRIDAY...SLIGHT CHANCE -RA AND MVFR/IFR.
RATZER
&&
.MARINE...
250 AM CST
HIGH PRESSURE MOVING EAST ACROSS THE UPPER OHIO VALLEY TO THE MID
ATLANTIC REGION TODAY...AND LOW PRESSURE MOVING FROM MANITOBA TO
HUDSON BAY...WILL ALLOW SOUTH-SOUTHWEST WINDS TO PERSIST ACROSS
LAKE MICHIGAN. THE GRADIENT WILL TIGHTEN DURING THE DAY IN
RESPONSE TO PRESSURE FALLS ASSOCIATED WITH THE CANADIAN LOW...
WITH SOUTHERLY WINDS INCREASING INTO THE 30 KT RANGE THIS
AFTERNOON INTO TONIGHT OVER THE NORTHERN PART OF THE LAKE. THE
GRADIENT WILL THEN WEAKEN SUNDAY AS A WEAK COLD FRONT SLIDES
SOUTHEAST ACROSS THE LAKE...WITH WINDS SHIFTING TO THE WEST-
NORTHWEST. WEAK HIGH PRESSURE WILL BUILD IN BEHIND THE FRONT
SUNDAY NIGHT INTO MONDAY...BEFORE THE PATTERN REVERTS TO LOW
PRESSURE LIFTING NORTHEAST ACROSS CANADA AND NORTH OF THE LAKES
AND BRINGS A RETURN TO SOUTH-SOUTHWEST WINDS INTO EARLY NEXT WEEK.
RATZER
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...DENSE FOG ADVISORY...ILZ019-ILZ021-ILZ023-ILZ032-ILZ033-ILZ039
UNTIL NOON SATURDAY.
IN...DENSE FOG ADVISORY...INZ001-INZ002-INZ010-INZ011-INZ019 UNTIL
NOON SATURDAY.
LM...NONE.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1037 AM CST SAT DEC 5 2015
.UPDATE...
1037 AM CST
WE HAVE ENDED THE DENSE FOG ADVISORY FOR MOST AREAS NORTH OF I80
IN ILLINOIS THIS MORNING...AND THE REST OF THE AREA WILL LIKELY BE
ABLE TO END AT THE CURRENT EXPIRATION TIME AT NOON. CONDITIONS
HAVE CLEARED UP RATHER QUICKLY ACROSS NORTHERN
ILLINOIS...ESPECIALLY NORTH OF I-88 AS OF THIS WRITING. IT APPEARS
LIKELY THAT THE NORTHERN AND WESTERN EDGES OF THIS CLOUD/FOG DECK
WILL CONTINUE TO SLOWLY DISSIPATE THROUGH THE AFTERNOON. THIS
COULD RESULT IN MY NORTHWESTERN INDIANA COUNTIES AND EAST CENTRAL
ILLINOIS COUNTIES BEING IN THE LOW CLOUDS FOR MOST OF THE
DAY...SIMILAR TO YESTERDAY.
CONSIDERING SKIES ARE CLEARING QUICK NORTH...I HAVE RAISE HIGHS THIS
AFTERNOON...AS THE AIRMASS OVER THE AREA SHOULD SUPPORT MILD
CONDITIONS WELL INTO THE 40S OUTSIDE OF THE CLOUDY AREAS.
THEREFORE...THE WARMEST CONDITIONS...NEAR 50 LOOK TO BE NORTH AND IN
CHICAGO...WITH COOLER CONDITIONS...ONLY IN THE UPPER 30S TO LOW 40S
IN MY SOUTHEASTERN AREAS. I HAVE UPDATED THE FORECAST TO LEAN IN
THIS DIRECTION.
ITS POSSIBLE THAT SOME FOG AND LOW CLOUDS COULD RETURN TONIGHT...BUT
I WILL ASSES THIS POTENTIAL THIS AFTERNOON.
KJB
&&
.SHORT TERM...
312 AM CST
THROUGH SUNDAY NIGHT...
LOW STRATUS AND FOG THE PRIMARY FORECAST CONCERNS OVER THE NEXT
COUPLE DAYS. SURFACE HIGH PRESSURE IS CENTERED OVER THE UPPER OHIO
VALLEY EARLY THIS MORNING AND IS PROGGED TO BUILD TOWARDS THE
MID ATLANTIC COAST OVER THE WEEKEND. SATELLITE IMAGERY AND SURFACE
OBS SHOWS LOW STRATUS AND FOG BLANKETING THE EASTERN 2/3 OR SO OF
ILLINOIS AND PRACTICALLY ALL OF INDIANA. CLOUDS HAVE BEEN STEADILY
SPREADING NORTHWEST OVERNIGHT AND SHOULD BLANKET THE ENTIRE
FORECAST AREA THROUGH THE MORNING. THEREAFTER...THE ONLY MODEL
THAT WANTS TO HOLD ONTO THE CLOUD COVER THROUGH THE MAJORITY OF
THE DAY IS THE HRRR WHICH SEEMS FAIRLY REASONABLE GIVEN LACK OF
EROSION YESTERDAY. MOST OTHER MODELS BEGIN TO ERODE THE STRATUS BY
MIDDAY HOWEVER A RATHER IMPRESSIVE LOW LEVEL INVERSION COULD KEEP
THE LOW LEVEL MOISTURE TRAPPED THROUGH MUCH OF THE WEEKEND. 05Z
AMDAR SOUNDING OUT OF THE CHICAGO AREA SHOWED 980MB TEMP OF 0.3C
SHARPLY WARMING TO 9.0C AROUND 935MB. LATEST FORECAST GOES UNDER
THE ASSUMPTION THAT MOST OF THE CWA WILL REMAIN UNDER OVERCAST
SKIES AND HAVE ADJUSTED TEMPS DOWN QUITE A BIT FROM PREVIOUS
FORECASTS. FAR NORTH CENTRAL ILLINOIS WILL HAVE THE BEST CHANCE TO
SEE SOME EROSION ALONG THE EDGE OF THE STRATUS DECK BUT CONFIDENCE
IS LOW HOW THIS WILL PLAY OUT OR WHERE TO DRAW THE LINE. AS IS
TYPICAL WITH THESE SCENARIOS THERE IS LARGE BUST POTENTIAL...WITH
HIGHS ONLY IN THE UPPER 30S TO AROUND 40 ON THE COLD END UNDER
CLOUDS ALL DAY BUT IF SUNSHINE IS ABLE TO BREAK THROUGH...THOSE
VERY WARM TEMPS ALOFT WOULD SUPPORT TEMPERATURES QUICKLY SHOOTING
UP WITH HIGHS IN THE LOW 50S. OVERNIGHT...BOUNDARY LAYER FLOW
BACKS SLIGHTLY SO WOULD ANTICIPATE ANY LOW CIGS TO SPREAD BACK TO
ANY AREAS IN NORTH CENTRAL ILLINOIS THAT MIGHT ERODE ALONG THE
EDGE OF THE STRATUS...BUT CONFIDENCE IS FAIRLY LOW HOW THIS WILL
PLAY OUT.
SATURDAY NIGHT INTO SUNDAY...AN UPPER LEVEL WAVE WILL TRANSLATE
EAST ACROSS THE PLAINS REACHING THE OHIO VALLEY BY SUNDAY
EVENING. MID LEVEL HEIGHT FALLS IN ADVANCE OF THIS SYSTEM BEGIN TO
OVERSPREAD NORTHERN ILLINOIS SATURDAY NIGHT THOUGH THE BULK OF THE
FORCING STAYS SOUTH OF THE CWA DURING THE DAY SUNDAY. OUTSIDE OF
THE POSSIBLE CONTINUING LOW STRATUS...FAIRLY LITTLE MOISTURE IS
EXPECTED WITH THIS SYSTEM. MIGHT BE ABLE TO SQUEEZE OUT SOME
DRIZZLE SATURDAY NIGHT INTO EARLY SUNDAY BUT OTHERWISE CONFINED
POPS TO SOUTHWEST AREAS OF THE CWA AND ONLY SLIGHT CHC. LOW LEVEL
CLOUDS IF STILL AROUND EXPECTED TO FINALLY ERODE SUNDAY...HOWEVER
MID AND HIGH CLOUD COVER WILL BE INCREASING ACROSS THE AREA.
DEUBELBEISS
&&
.LONG TERM...
312 AM CST
MONDAY THROUGH FRIDAY...
UPPER PATTERN WILL BECOME ZONAL FOR THE UPCOMING WEEK WITH A
SERIES OF DISTURBANCES BRINGING PERIODIC CHANCES FOR PRECIP
PARTICULARLY THE LATTER HALF OF THE WEEK. TEMPERATURES SHOULD
REMAIN MILD THROUGH THE ENTIRE WEEK WITH A GRADUAL WARMING TREND
EXPECTED. TEMPERATURES ON MONDAY WILL MAX IN THE MID 40S ACROSS
THE FORECAST AREA AND LOW 50S ARE POSSIBLE BY THURSDAY AND FRIDAY.
BOTH THE ECMWF AND GFS ADVERTISE A SHORTWAVE TROUGH DROPPING
ACROSS UPPER MIDWEST/WESTERN GREAT LAKES WEDNESDAY NIGHT.
THEN...WILL HAVE TO KEEP A CLOSE EYE ON A POTENTIALLY MORE POTENT
SYSTEM LATE IN THE WEEK...THOUGH MODELS CONTINUE TO BOUNCE AROUND
ON THE DETAILS AS THEY STRUGGLE TO HANDLE THE PHASING OF UPPER
LEVEL ENERGY.
DEUBELBEISS
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 16Z...
* PATCHY IFR CIG/VIS IN STRATUS/FOG QUICKLY LIFTING TO VFR.
* POTENTIAL FOR REDEVELOPMENT OR LOWERING OF IFR/LIFR STRATUS/FOG
AGAIN TONIGHT.
RATZER/BEACHLER
//DISCUSSION...UPDATED 12Z...
STRATUS/FOG WHICH SPREAD ACROSS TERMINALS OVERNIGHT WILL REMAIN
THIS MORNING...WITH LIFR/VLIFR CONDITIONS GRADUALLY IMPROVING TO
IFR MID/LATE MORNING. WOULD EXPECT SOME EROSION AROUND THE EDGES
OF THE STRATUS DECK FROM MID-MORNING ON...THOUGH DEGREE OF
CLEARING LIKELY TO BE LIMITED THE FARTHER SOUTHEAST ONE GOES. IT
IS POSSIBLE SOME CLEARING EVEN TO VFR WILL OCCUR BY EARLY
AFTERNOON...MOST LIKELY AT RFD NEAR THE EDGE OF THE CLOUD DECK.
EVEN IF CIGS LINGER...WILL LIKELY SEE A DIURNAL RISE TO CIGS AND A
SIGNIFICANT IMPROVEMENT IN VIS. TOUGH QUESTION IS WHAT OCCURS
TONIGHT...AS CLEARING WOULD LIKELY SET THE STAGE FOR SOME
NORTHWARD REDEVELOPMENT SIMILAR TO LAST NIGHT...AND IF A CEILING
LINGERS LIKELY A DIURNAL LOWERING OF VIS/CIG. THUS WHILE GENERAL
TREND OF FORECAST IS FAIRLY GOOD CONFIDENCE...SPECIFIC DETAILS IN
TIMING AND EXACT CIG HEIGHTS/VIS REMAIN RATHER LOW.
WINDS WILL REMAIN GENERALLY SOUTHERLY...BETWEEN ABOUT 200-170 DEG
AND 10 KTS OR LESS.
RATZER
//ORD AND MDW CONFIDENCE...UPDATED 14Z...
* HIGH IN CURRENT CONDITIONS IMPROVEMENT.
* LOW IN TIMING IMPROVEMENT TODAY...AND TRENDS TONIGHT.
RATZER/BEACHLER
//OUTLOOK FOR ORD/MDW FOR 00Z MONDAY-12Z SATURDAY...UPDATED 12Z...
SUNDAY NIGHT THROUGH TUESDAY...PRIMARILY VFR. SMALL DAY TO DAY
CHANCE OF IFR CIGS/FOG DURING LATE NIGHTS/MORNINGS.
WEDNESDAY...SLIGHT CHANCE -RA/MVFR.
THURSDAY...VFR/MVFR CIGS.
FRIDAY...SLIGHT CHANCE -RA AND MVFR/IFR.
RATZER
&&
.MARINE...
250 AM CST
HIGH PRESSURE MOVING EAST ACROSS THE UPPER OHIO VALLEY TO THE MID
ATLANTIC REGION TODAY...AND LOW PRESSURE MOVING FROM MANITOBA TO
HUDSON BAY...WILL ALLOW SOUTH-SOUTHWEST WINDS TO PERSIST ACROSS
LAKE MICHIGAN. THE GRADIENT WILL TIGHTEN DURING THE DAY IN
RESPONSE TO PRESSURE FALLS ASSOCIATED WITH THE CANADIAN LOW...
WITH SOUTHERLY WINDS INCREASING INTO THE 30 KT RANGE THIS
AFTERNOON INTO TONIGHT OVER THE NORTHERN PART OF THE LAKE. THE
GRADIENT WILL THEN WEAKEN SUNDAY AS A WEAK COLD FRONT SLIDES
SOUTHEAST ACROSS THE LAKE...WITH WINDS SHIFTING TO THE WEST-
NORTHWEST. WEAK HIGH PRESSURE WILL BUILD IN BEHIND THE FRONT
SUNDAY NIGHT INTO MONDAY...BEFORE THE PATTERN REVERTS TO LOW
PRESSURE LIFTING NORTHEAST ACROSS CANADA AND NORTH OF THE LAKES
AND BRINGS A RETURN TO SOUTH-SOUTHWEST WINDS INTO EARLY NEXT WEEK.
RATZER
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...DENSE FOG ADVISORY...ILZ019-ILZ021-ILZ023-ILZ032-ILZ033-ILZ039
UNTIL NOON SATURDAY.
IN...DENSE FOG ADVISORY...INZ001-INZ002-INZ010-INZ011-INZ019 UNTIL
NOON SATURDAY.
LM...NONE.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
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WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1013 AM CST SAT DEC 5 2015
.SHORT TERM...
312 AM CST
THROUGH SUNDAY NIGHT...
LOW STRATUS AND FOG THE PRIMARY FORECAST CONCERNS OVER THE NEXT
COUPLE DAYS. SURFACE HIGH PRESSURE IS CENTERED OVER THE UPPER OHIO
VALLEY EARLY THIS MORNING AND IS PROGGED TO BUILD TOWARDS THE
MID ATLANTIC COAST OVER THE WEEKEND. SATELLITE IMAGERY AND SURFACE
OBS SHOWS LOW STRATUS AND FOG BLANKETING THE EASTERN 2/3 OR SO OF
ILLINOIS AND PRACTICALLY ALL OF INDIANA. CLOUDS HAVE BEEN STEADILY
SPREADING NORTHWEST OVERNIGHT AND SHOULD BLANKET THE ENTIRE
FORECAST AREA THROUGH THE MORNING. THEREAFTER...THE ONLY MODEL
THAT WANTS TO HOLD ONTO THE CLOUD COVER THROUGH THE MAJORITY OF
THE DAY IS THE HRRR WHICH SEEMS FAIRLY REASONABLE GIVEN LACK OF
EROSION YESTERDAY. MOST OTHER MODELS BEGIN TO ERODE THE STRATUS BY
MIDDAY HOWEVER A RATHER IMPRESSIVE LOW LEVEL INVERSION COULD KEEP
THE LOW LEVEL MOISTURE TRAPPED THROUGH MUCH OF THE WEEKEND. 05Z
AMDAR SOUNDING OUT OF THE CHICAGO AREA SHOWED 980MB TEMP OF 0.3C
SHARPLY WARMING TO 9.0C AROUND 935MB. LATEST FORECAST GOES UNDER
THE ASSUMPTION THAT MOST OF THE CWA WILL REMAIN UNDER OVERCAST
SKIES AND HAVE ADJUSTED TEMPS DOWN QUITE A BIT FROM PREVIOUS
FORECASTS. FAR NORTH CENTRAL ILLINOIS WILL HAVE THE BEST CHANCE TO
SEE SOME EROSION ALONG THE EDGE OF THE STRATUS DECK BUT CONFIDENCE
IS LOW HOW THIS WILL PLAY OUT OR WHERE TO DRAW THE LINE. AS IS
TYPICAL WITH THESE SCENARIOS THERE IS LARGE BUST POTENTIAL...WITH
HIGHS ONLY IN THE UPPER 30S TO AROUND 40 ON THE COLD END UNDER
CLOUDS ALL DAY BUT IF SUNSHINE IS ABLE TO BREAK THROUGH...THOSE
VERY WARM TEMPS ALOFT WOULD SUPPORT TEMPERATURES QUICKLY SHOOTING
UP WITH HIGHS IN THE LOW 50S. OVERNIGHT...BOUNDARY LAYER FLOW
BACKS SLIGHTLY SO WOULD ANTICIPATE ANY LOW CIGS TO SPREAD BACK TO
ANY AREAS IN NORTH CENTRAL ILLINOIS THAT MIGHT ERODE ALONG THE
EDGE OF THE STRATUS...BUT CONFIDENCE IS FAIRLY LOW HOW THIS WILL
PLAY OUT.
SATURDAY NIGHT INTO SUNDAY...AN UPPER LEVEL WAVE WILL TRANSLATE
EAST ACROSS THE PLAINS REACHING THE OHIO VALLEY BY SUNDAY
EVENING. MID LEVEL HEIGHT FALLS IN ADVANCE OF THIS SYSTEM BEGIN TO
OVERSPREAD NORTHERN ILLINOIS SATURDAY NIGHT THOUGH THE BULK OF THE
FORCING STAYS SOUTH OF THE CWA DURING THE DAY SUNDAY. OUTSIDE OF
THE POSSIBLE CONTINUING LOW STRATUS...FAIRLY LITTLE MOISTURE IS
EXPECTED WITH THIS SYSTEM. MIGHT BE ABLE TO SQUEEZE OUT SOME
DRIZZLE SATURDAY NIGHT INTO EARLY SUNDAY BUT OTHERWISE CONFINED
POPS TO SOUTHWEST AREAS OF THE CWA AND ONLY SLIGHT CHC. LOW LEVEL
CLOUDS IF STILL AROUND EXPECTED TO FINALLY ERODE SUNDAY...HOWEVER
MID AND HIGH CLOUD COVER WILL BE INCREASING ACROSS THE AREA.
DEUBELBEISS
&&
.LONG TERM...
312 AM CST
MONDAY THROUGH FRIDAY...
UPPER PATTERN WILL BECOME ZONAL FOR THE UPCOMING WEEK WITH A
SERIES OF DISTURBANCES BRINGING PERIODIC CHANCES FOR PRECIP
PARTICULARLY THE LATTER HALF OF THE WEEK. TEMPERATURES SHOULD
REMAIN MILD THROUGH THE ENTIRE WEEK WITH A GRADUAL WARMING TREND
EXPECTED. TEMPERATURES ON MONDAY WILL MAX IN THE MID 40S ACROSS
THE FORECAST AREA AND LOW 50S ARE POSSIBLE BY THURSDAY AND FRIDAY.
BOTH THE ECMWF AND GFS ADVERTISE A SHORTWAVE TROUGH DROPPING
ACROSS UPPER MIDWEST/WESTERN GREAT LAKES WEDNESDAY NIGHT.
THEN...WILL HAVE TO KEEP A CLOSE EYE ON A POTENTIALLY MORE POTENT
SYSTEM LATE IN THE WEEK...THOUGH MODELS CONTINUE TO BOUNCE AROUND
ON THE DETAILS AS THEY STRUGGLE TO HANDLE THE PHASING OF UPPER
LEVEL ENERGY.
DEUBELBEISS
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 16Z...
* PATCHY IFR CIG/VIS IN STRATUS/FOG QUICKLY LIFTING TO VFR.
* POTENTIAL FOR REDEVELOPMENT OR LOWERING OF IFR/LIFR STRATUS/FOG
AGAIN TONIGHT.
RATZER/BEACHLER
//DISCUSSION...UPDATED 12Z...
STRATUS/FOG WHICH SPREAD ACROSS TERMINALS OVERNIGHT WILL REMAIN
THIS MORNING...WITH LIFR/VLIFR CONDITIONS GRADUALLY IMPROVING TO
IFR MID/LATE MORNING. WOULD EXPECT SOME EROSION AROUND THE EDGES
OF THE STRATUS DECK FROM MID-MORNING ON...THOUGH DEGREE OF
CLEARING LIKELY TO BE LIMITED THE FARTHER SOUTHEAST ONE GOES. IT
IS POSSIBLE SOME CLEARING EVEN TO VFR WILL OCCUR BY EARLY
AFTERNOON...MOST LIKELY AT RFD NEAR THE EDGE OF THE CLOUD DECK.
EVEN IF CIGS LINGER...WILL LIKELY SEE A DIURNAL RISE TO CIGS AND A
SIGNIFICANT IMPROVEMENT IN VIS. TOUGH QUESTION IS WHAT OCCURS
TONIGHT...AS CLEARING WOULD LIKELY SET THE STAGE FOR SOME
NORTHWARD REDEVELOPMENT SIMILAR TO LAST NIGHT...AND IF A CEILING
LINGERS LIKELY A DIURNAL LOWERING OF VIS/CIG. THUS WHILE GENERAL
TREND OF FORECAST IS FAIRLY GOOD CONFIDENCE...SPECIFIC DETAILS IN
TIMING AND EXACT CIG HEIGHTS/VIS REMAIN RATHER LOW.
WINDS WILL REMAIN GENERALLY SOUTHERLY...BETWEEN ABOUT 200-170 DEG
AND 10 KTS OR LESS.
RATZER
//ORD AND MDW CONFIDENCE...UPDATED 14Z...
* HIGH IN CURRENT CONDITIONS IMPROVEMENT.
* LOW IN TIMING IMPROVEMENT TODAY...AND TRENDS TONIGHT.
RATZER/BEACHLER
//OUTLOOK FOR ORD/MDW FOR 00Z MONDAY-12Z SATURDAY...UPDATED 12Z...
SUNDAY NIGHT THROUGH TUESDAY...PRIMARILY VFR. SMALL DAY TO DAY
CHANCE OF IFR CIGS/FOG DURING LATE NIGHTS/MORNINGS.
WEDNESDAY...SLIGHT CHANCE -RA/MVFR.
THURSDAY...VFR/MVFR CIGS.
FRIDAY...SLIGHT CHANCE -RA AND MVFR/IFR.
RATZER
&&
.MARINE...
250 AM CST
HIGH PRESSURE MOVING EAST ACROSS THE UPPER OHIO VALLEY TO THE MID
ATLANTIC REGION TODAY...AND LOW PRESSURE MOVING FROM MANITOBA TO
HUDSON BAY...WILL ALLOW SOUTH-SOUTHWEST WINDS TO PERSIST ACROSS
LAKE MICHIGAN. THE GRADIENT WILL TIGHTEN DURING THE DAY IN
RESPONSE TO PRESSURE FALLS ASSOCIATED WITH THE CANADIAN LOW...
WITH SOUTHERLY WINDS INCREASING INTO THE 30 KT RANGE THIS
AFTERNOON INTO TONIGHT OVER THE NORTHERN PART OF THE LAKE. THE
GRADIENT WILL THEN WEAKEN SUNDAY AS A WEAK COLD FRONT SLIDES
SOUTHEAST ACROSS THE LAKE...WITH WINDS SHIFTING TO THE WEST-
NORTHWEST. WEAK HIGH PRESSURE WILL BUILD IN BEHIND THE FRONT
SUNDAY NIGHT INTO MONDAY...BEFORE THE PATTERN REVERTS TO LOW
PRESSURE LIFTING NORTHEAST ACROSS CANADA AND NORTH OF THE LAKES
AND BRINGS A RETURN TO SOUTH-SOUTHWEST WINDS INTO EARLY NEXT WEEK.
RATZER
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...DENSE FOG ADVISORY...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-ILZ010-
ILZ011-ILZ012-ILZ013-ILZ014-ILZ019-ILZ020-ILZ021-ILZ022-
ILZ023-ILZ032-ILZ033-ILZ039 UNTIL NOON SATURDAY.
IN...DENSE FOG ADVISORY...INZ001-INZ002-INZ010-INZ011-INZ019 UNTIL
NOON SATURDAY.
LM...NONE.
&&
$$
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FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
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WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1139 AM CST SAT DEC 5 2015
.UPDATE...
ISSUED AT 441 AM CST SAT DEC 5 2015
THE FOG HAS FILLED IN AND THE EDGE IS NOW ALONG A LINE FROM
GENESEO TO MOUNT CARROLL TO FREEPORT AND CONTINUING TO EXPAND
WEST. IT BEGAN TO SHOW A MORE DISTINCTIVE PUSH TO THE WEST OVER
THE PAST FEW HOURS...ESPECIALLY OVER THE NORTHERN PART OF THE
AREA. THEREFORE...DID EXPAND THE ADVISORY A TIER OF COUNTIES TO
THE WEST. THE FOG IS NOW CLOSE TO WHERE THE HRRR MODEL HAS BEEN
INDICATING IT WOULD REACH SO NOT ANTICIPATING THE NEED TO EXPAND
ANY FURTHER WEST AT THIS TIME. ALSO...THERE IS A DIMINISHING TREND
IN THE FOG ALONG AND EAST OF HIGHWAY 40 AND INTERSTATE 155 FROM
BRADFORD TO SOUTH OF PEORIA AND IF THIS CONTINUES TO ERODE THE FOG
FROM THE MIDDLE OUT...THE ADVISORY WOULD LIKELY BE NEEDED TO BE
CANCELLED EARLY. HOWEVER MODELS ARE STILL STUCK ON THE IDEA OF THE
FOG STICKING AROUND UNTIL EARLY AFTERNOON IN ALL AREAS. BELIEVE
THE MODELS CONTINUE TO BE OVERDONE AND FOG WILL BE ERODED BY LATE
THIS MORNING.
&&
.SYNOPSIS...
ISSUED AT 345 AM CST SAT DEC 5 2015
AT 09Z WATER VAPOR IMAGERY SHOWED BROAD RIDGING OVER
THE EASTERN PART OF THE CONUS WHICH EXTENDED THROUGH ONTARIO. A WEAK
SHORTWAVE WAS NOTED FROM THE EASTERN DAKOTAS THROUGH THE MID
MISSISSIPPI RIVER VALLEY WITH A BROAD LONGWAVE TROUGH IN PLACE
ACROSS THE WESTERN HALF OF THE CONUS. AT THE SURFACE...HIGH PRESSURE
WAS IN PLACE OVER OHIO WITH WEAK ANTI-CYCLONIC FLOW PUSHING ACROSS
ILLINOIS. A TROUGH OF LOW PRESSURE WAS IN PLACE ACROSS THE HIGH
PLAINS...LEADING TO AN INCREASING PRESSURE GRADIENT GOING WEST FROM
ILLINOIS THROUGH THE PLAINS. THIS LED TO A CHANGE IN LOW LEVEL FLOW
FROM THE SOUTHWEST...AND LESSER INFLUENCE FROM THE EASTERN AIRMASS.
FOG WAS ABUNDANT IN AREAS UNDER THE INFLUENCE OF THE SURFACE HIGH
WITH DENSE FOG BEING OBSERVED ACROSS MUCH OF ILLINOIS.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 345 AM CST SAT DEC 5 2015
PRIMARY CONCERNS WITH THIS FORECAST CYCLE IS WITH FOG THIS MORNING
AND TEMPERATURES TODAY. THEN AGAIN WITH FOG POTENTIAL AGAIN TONIGHT.
THE FOG CONTINUES TO EXPAND WESTWARD BUT THE LEADING EDGE DOESN/T
SEEM TO BE MAKING MUCH MORE PROGRESS WEST OVER THE PAST HOUR AND
HAS MAINLY BEEN FILLING IN. SO...MAY BE CLOSE TO WHERE IT WILL END
UP...MAINLY EAST OF A LINE FROM MACOMB TO GENESEO TO FREEPORT. THE
MORE WIDESPREAD FOG REMAINS OVER BUREAU AND PUTNAM
COUNTIES...ALTHOUGH HAS EDGED INTO WHITESIDE AND HENRY COUNTIES.
AT THIS POINT...WILL FOREGO EXPANDING THE ADVISORY AS THE FOG IS
NOT QUITE AS WIDESPREAD BUT WILL CONTINUE TO WATCH ITS BEHAVIOR
THROUGH THE MORNING. AS FOR TIMING OF THE FOG LIFTING. WITH THE
TIME OF YEAR AND NOT MUCH FOR LOW LEVEL FLOW THIS MORNING...NOT
EXPECTING A FAST CLEARING OF THE FOG AND WILL LIKELY CONTINUE INTO
MID OR EVEN LATE MORNING...BUT WITH THE LOCAL AREA ON THE
EDGE...WILL LIKELY SEE THE FOG LIFTED EARLIER THAN AREAS TO THE
EAST.
TEMPERATURES OVER THE EASTERN PART OF THE FORECAST AREA WILL BE
HEAVILY INFLUENCED BY THE FOG THE LONGER IT PERSISTS. DID GO A BIT
COOLER FOR HIGHS WHERE FOG/CLOUDS WILL BE IN PLACE THROUGH THE
MORNING...DELAYING THE WARMING. ELSEWHERE...SHOULD SEE A GOOD WARM-
UP FOR THIS TIME OF YEAR AS DECENT MIXING SHOULD OCCUR TO AROUND
950MB WHICH WOULD BRING TEMPERATURES INTO THE UPPER 40S AND LOW 50S.
THEN FOR TONIGHT...AS THE TROUGH OF LOW PRESSURE APPROACHES FROM THE
WEST...SO WILL CLOUDS. BUT MOST MODELS INDICATE MANY WILL STAY WEST
OF THE FORECAST ARE THROUGH MUCH OF THE NIGHT. THERE ARE INDICATIONS
THOUGH THAT FOG WILL REDEVELOP ACROSS ILLINOIS DURING THE EVENING
AND THEN EXPAND WEST OVERNIGHT AND BACK INTO THE EASTERN PART OF THE
FORECAST AREA. DON/T HAVE HIGH CONFIDENCE ON ANYTHING DENSE...BUT
DID INCLUDE FOG MENTION IN THE FORECAST FOR THESE AREAS TONIGHT.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 345 AM CST SAT DEC 5 2015
A CLOSED UPPER LOW CONTINUES TO BE FORECAST BY ALL MODELS TO
PROGRESS THROUGH IOWA AND ILLINOIS DURING THE DAY SUNDAY INTO EARLY
SUNDAY EVENING. AS HAS BEEN THE CASE IN THE PAST FEW DAYS OF MODEL
DATA...IT APPEARS THIS SYSTEM WILL HAVE ACCESS TO LITTLE IF ANY
MOISTURE FROM THE SOUTH. THE SMALL AMOUNT OF MOISTURE DRAWN FROM
ITS PACIFIC ORIGINS WILL LIKELY WRING OUT IN LIGHT RAIN...WITH QPF
AMOUNTS UNDER 1 TENTH OF AN INCH. WE WILL CONTINUE WITH FAIRLY LOW
POPS FOR WHAT COULD END UP BEING A HIGH POP LOW QPF EVENT IF
SATURATION CAN BE ACHIEVED OVER A LARGER PORTION OF THE CWA. UNDER
THE HIGH CONFIDENCE CLOUDY SKIES...SUNDAY AFTERNOON TEMPERATURES
SHOULD BE HELD TO THE LOWER 40S IN MOST LOCATIONS...AND UNDER
SIMILARLY MOSTLY CLOUDY SKIES SUNDAY NIGHT...LOWS SHOULD ONLY FALL
TO THE THE LOWER 30S. IT BEARS WATCHING LATE SUNDAY NIGHT AS THE MID
CLOUDS MOVE OFF TO THE EAST...SOME SHALLOW FOG DEVELOPMENT APPEARS
POSSIBLE...AND THAT COULD BE DENSE IF WIDESPREAD LIGHT RAIN DOES
OCCUR SUNDAY.
WEAK HIGH PRESSURE WILL MOVE OVER THE AREAS MONDAY MORNING...WITH
RETURN FLOW QUICKLY DEVELOPING FOR MONDAY NIGHT AND TUESDAY. HIGHS
MONDAY AND TUESDAY SHOULD ONCE AGAIN REACH THE MID 40S TO NEAR 50.
ANOTHER WEAK UPPER LOW SHOULD BRUSH THE REGION TUESDAY AFTERNOON AND
NIGHT...WITH LOW POPS NORTH FOR LIGHT RAIN. FOLLOWING THAT...A MORE
SIGNIFICANT DEEP PROGRESSIVE UPPER TROF WILL SWEEP THROUGH THE
MIDWEST BY LATE IN THE WORK WEEK. AHEAD OF THIS FRONT/TROF
PASSAGE...AT LEAST TWO DAYS OF SUSTAINED WAA WILL TAKE PLACE. THIS
WILL EVENTUALLY DRAW UP SOME DEEPER MOISTURE THAN WE WILL HAVE SEEN
IN OVER WEEK...AND WITH THAT...A CHANCE FOR SEASONALLY SIGNIFICANT
RAINFALL IS GROWING FOR THE THURSDAY AND FRIDAY TIME PERIOD. THE
ATMOSPHERE WOULD CERTAINLY BE MILD ENOUGH FOR ALL RAIN DURING THOSE
TWO DAYS. HIGHS WOULD EASILY REACH THE MID 40S TO AROUND 50 IN THE
MOIST AIRMASS...WITH LOWS IN THE MID 30S TO MID 40S.
ERVIN
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1136 AM CST SAT DEC 5 2015
VFR CONDITIONS TO PREVAIL THE NEXT 24 HOURS WITH INCREASING HIGH
CLOUDS TONIGHT AHEAD OF A WEAK UPPER LEVEL DISTURBANCE. SOUTH WINDS
OF 5 TO 15 KTS TO CONTINUE THROUGH MID DAY SUNDAY. AFTER 06/14Z...ISOLATED
TO SCATTERED COVERAGE OF LIGHT RAIN OR SPRINKLES POSSIBLE AT THE TERMINALS
WITH COVERAGE AND CONFIDENCE TOO LOW TO INCLUDE IN TAFS EXCEPT FOR VICINITY
WORDING.
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
UPDATE...BROOKS
SYNOPSIS...ERVIN
SHORT TERM...ERVIN
LONG TERM...BROOKS
AVIATION...NICHOLS
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
323 PM EST SAT DEC 5 2015
.DISCUSSION...
SIGNIFICANT RIDGING ALOFT HAS SUPPORTED A VERY WARM LOWER AND MID
TROPOSPHERIC COLUMN ACROSS THE UPPER MIDWEST AND GREAT LAKES
REGIONS. THE CONSEQUENCE OF THIS MASS CONFIGURATION IS THE
PRODUCTION OF A VERY SHALLOW COOL LAYER AT THE SURFACE THAT CANNOT
MIX WITH THE SLIGHTLY ELEVATED WARM LATER DUE TO THE EXTREMELY
STABLE TRANSITION LAYER. THE MOISTURE CONTENT BELOW THIS STRONG
INVERSION IS REMAINING FAIRLY CONSTANT...SO IT SIMPLY GOES THROUGH A
CONDENSATION CYCLE DURING THE NOCTURNAL HOURS AND EVAPORATION DURING
THE DIURNAL WINDOW. GIVEN THE RATHER STEADY-STATE SURFACE RIDGING
AND LACK OF AIRMASS REPLACEMENT NEAR THE GROUND...THIS CYCLE WILL
CONTINUE CERTAINLY THROUGH TONIGHT AND INDICATIONS ARE AN ADDITIONAL
TWO MORE DAYS BEFORE MORE ROBUST SOUTHWESTERLY FLOW BECOMES
ESTABLISHED ON TUESDAY.
THE VERY SHALLOW NATURE OF THE COOL LAYER /SEE 12Z KDTX RAOB/ ALLOWS
FOR GREATER TRAPPING OF MOISTURE IN THE LOWER ELEVATION REGIONS OF
METRO DETROIT. HENCE...THAT AREA IS THE LAST TO SCOUR OUT THE FOG
AND LOW CLOUDS. THERE IS STILL AN OPPORTUNITY TO CATCH A GLIMPSE OF
THE SUN PRIOR TO SUNSET...BUT IT WILL NOT BE LONG LIVED. EXPECT FOG
FORMATION TO QUICKLY RESUME AFTER SUNSET AND QUICKLY FILL ACROSS
SOUTHEAST MICHIGAN ONCE AGAIN. HRRR AND HRRRX GUIDANCE HAS BEEN
RATHER SKILLFUL WITH TODAY/S EPISODE AND OFFER REASONABLE DEPICTIONS
FOR THE NOCTURNAL CYCLE ONCE AGAIN TONIGHT - THOUGH MAY BE A LITTLE
TOO PESSIMISTIC EARLY IN THE PROCESS. HOWEVER...THESE SITUATIONS ARE
ALL OR NOTHING ONCE DEVELOPMENT COMMENCES. DENSE FOG IS HIGHLY
LIKELY AGAIN TONIGHT...BUT THE TIMING OF ONSET IS IN QUESTION GIVEN
THE LINGERING LOW CLOUDS ACROSS METRO DETROIT AND SOME DEGREE OF
DEWPOINT SEPARATION IN THOSE LOCATIONS WHERE THE SUN HAS BEEN MORE
ACTIVE.
EQUALLY CHALLENGING WILL BE THE SPATIAL QUALITY OF THE FOG / STRATUS
FIELD. EXPECT THE GLACIAL RIDGE TO EXPERIENCE THE LEAST INFLUENCE
ONCE AGAIN AS ELEVATION INTO THE INVERSION LAYER WILL DIMINISH THE
MOISTURE QUALITY AND FOG PRODUCTION EFFICIENCY. WHILE THE LOWER
ELEVATIONS TO THE SOUTH SHOULD HAVE A SIMILAR OUTCOME AS
WITNESSED TODAY.
THE CLOUDS AND FOG WILL SLOWLY GIVE WAY TO SUN PRIOR TO MIDDAY ON
SUNDAY...WITH THE RIDGE LOCATIONS STARTING MUCH EARLIER. THE DELAYED
START TO INSOLATION WILL ONCE AGAIN KEEP TEMPS BELOW STATISTICAL
GUIDANCE...AND IF CLOUDS REFUSE TO BREAK...MUCH BELOW AS
DEMONSTRATED TODAY.
SURFACE HIGH PRESSURE WILL REMAIN OVER THE GREAT LAKES REGION ON
TUESDAY KEEPING SOUTHEAST MICHIGAN DRY. THIS HIGH WILL SLOWLY DRIFT
TOWARDS THE ATLANTIC COAST ON WEDNESDAY AS A SHORTWAVE TROUGH PIVOTS
THROUGH THE GREAT LAKES RESULTING IN A CHANCE OF RAIN SHOWERS ON
WEDNESDAY. WEAK SURFACE RIDGING WILL KEEP US DRY FOR WEDNESDAY NIGHT
HOWEVER A STRONGER LOW PRESSURE SYSTEM QUICKLY FOLLOWS ON THURSDAY.
BEST CHANCE OF PRECIP WITH THE LOW WILL BE ACROSS THE NORTHERN CWA.
A COLD FRONT TRACKS ACROSS THE SOUTHERN GREAT LAKES ON THURSDAY
NIGHT AND INTO FRIDAY BRINGING A BETTER CHANCE OF RAIN TO THE ENTIRE
CWA. A MORE ORGANIZED SURFACE LOW PRESSURE SYSTEM IS FORECASTED TO
IMPACT THE AREA NEXT WEEKEND...HOWEVER...MODEL TENDENCIES ARE
INCONSISTENT IN TIMING OF THIS SYSTEM AT THIS TIME. HAVE LEFT JUST
CHANCE POPS /30 TO 40 PERCENT/ IN THE FORECAST FOR NOW.
&&
.MARINE...
HIGH PRESSURE OVER THE OHIO VALLEY REGION WILL PERSIST THROUGH
THE WEEKEND KEEPING LIGHT SOUTHWESTERLY WINDS ACROSS HURON.
BY MID WEEK A STRONGER FRONT WILL APPROACH FROM THE WEST WITH
INCREASING SPEEDS. HOWEVER WITH UNSEASONABLY MILD AIR IN
PLACE...BOUNDARY LAYER MIXING WILL BE MINIMAL AND WINDS SHOULD
HAVE NO TROUBLE REMAINING SUB-GALE. FOR THE LONGER TERM, THE NEXT
MAJOR FRONTAL SYSTEM IS POSSIBLE NEXT WEEKEND AND COULD BRING
BRIEF GALES TO THE REGION.
&&
.AVIATION...ISSUED 1206 PM EST SAT DEC 5 2015
ADVECTIVE FOG EVENT FROM LAST NIGHT LED TO AN AVIATION MESS
THIS MORNING. MOISTURE IS PRETTY SHALLOW BUT SOLIDLY LOCKED IN DUE
TO TREMENDOUS INVERSION WITH BASE AT ABOUT 300 FEET AGL. LOWER
ELEVATION AREAS SOUTH OF THE GLACIAL RIDGE ARE EXPERIENCING SLIGHT
UPSLOPE SURFACE FLOW THAT IS REINFORCING A BAD SITUATION. IT IS
ENTIRELY LIKELY THAT LOW CIGS ARE GOING TO PERSIST RIGHT THROUGH
THE NIGHT AS RAP SOUNDINGS KEEP STRONG INVERSION IN PLACE. FROM A
VBSY PERSPECTIVE WILL LIKELY SEE A SLIGHT DIURNAL RECOVERY FROM
LIFR TO IFR FOR THE LATTER HALF OF THE AFTERNOON... BUT LATEST HRRR
RUNS STRONGLY SUGGEST SOCKING BACK IN SHORTLY AFTER SUNSET. NORTH OF
THE RIDGE... THINGS ARE QUICKLY IMPROVING LATE THIS MORNING AT PTK..
FNT.. AND MBS. THESE LOCATIONS SHOULD ALL BE VFR AROUND 18-19Z.
AGAIN THOUGH... HRRR RUNS ARE HINTING AT AN ADVECTIVE PUSH
NORTHWARD OF LOW CIGS AND FOG THIS EVENING SO BROUGHT LIFR
CONDITIONS IN AGAIN BY 01-04Z.
FOR DTW...TRENDS AND MODELS ARE INCREASING CONFIDENCE THAT
PROLONGED PERIOD OF LIFR/IFR VSBY WILL IMPACT METRO THROUGH THE NEXT
20 OR SO HOURS. STEEP PERSISTENT LOW LEVEL INVERSION... WEAK
UPSLOPE... AND LOW DECEMBER SUN ANGLE ALL CONSPIRING TO LOCK IN POOR
CONDITIONS. AGAIN... SLIGHT DIURNAL TRENDS COULD IMPROVE VSBY TO 1-3
NILES FOR A FEW HOURS THIS AFTERNOON BEFORE LOWERING AGAIN WITH
SUNSET.
//DTW THRESHOLD PROBABILITIES...
* HIGH CONFIDENCE CEILINGS WILL BE BELOW 5000 FT THROUGH SUNDAY
MORNING.
* HIGH CONFIDENCE IN CIGS AT OR BELOW 200 FT THROUGH 20Z TODAY AND
AGAIN FROM 00Z TO 16Z SUNDAY.
* MODERATE TO HIGH CONFIDENCE IN VSBY 1/2 MILES OR LESS THROUGH 20Z
TODAY AND AGAIN FROM 00Z TO 16Z SUNDAY.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MICHIGAN WATERS OF LAKE ERIE...NONE.
&&
$$
DISCUSSION....MANN/RK
MARINE.......05
AVIATION.....05
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1216 PM EST SAT DEC 5 2015
LATEST UPDATE...
AVIATION
.SYNOPSIS...
ISSUED AT 320 AM EST SAT DEC 5 2015
HIGH PRESSURE WILL PRODUCE FAIR AND MILD WEATHER THROUGH THE
WEEKEND. HOWEVER AREAS OF DENSE FOG THIS MORNING WILL CAUSE
HAZARDOUS TRAVEL CONDITIONS. TEMPERATURES WILL CONTINUE TO AVERAGE
AT LEAST TEN TO FIFTEEN DEGREES ABOVE NORMAL THROUGH THE UPCOMING
WEEK.
&&
.UPDATE...
ISSUED AT 1155 AM EST SAT DEC 5 2015
WILL BE DROPPING THE DENSE FOG ADVISORY AS VISIBILITIES HAVE
IMPROVED LATE THIS MORNING. ALL REPORTING STATIONS ACROSS THE GRR
FORECAST AREA NOW HAVE AT LEAST A 1/2 MILE VISIBILITY. A
SIGNIFICANT IMPROVEMENT FROM EARLIER WHERE VISIBILITY WAS BETWEEN
ZERO AND A 1/4 MILE IN MANY AREAS.
THIS AFTERNOON...THE VERY SHALLOW STRATUS SHOULD ERODE AND SKIES
SHOULD TURN MOSTLY SUNNY AS WE WORK THROUGH THE AFTERNOON. HIGH
TEMPERATURES WILL TOP OUT IN THE MIDDLE TO UPPER 40S.
&&
.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 320 AM EST SAT DEC 5 2015
A FREEZING FOG ADVISORY REMAINS IN EFFECT FOR ALL OF OUR FCST AREA
THROUGH 15Z THIS MORNING. SFC OBS/GROUND TRUTH REPORTS CONTINUE TO
INDICATE AREAS OF DENSE FOG ACROSS MUCH OF OUR FCST AREA. THIS IN
CONJUNCTION WITH SFC TEMPS AT OR BELOW FREEZING ACROSS PORTIONS OF
OUR AREA WILL RESULT IN HAZARDOUS TRAVEL CONDITIONS THROUGH MID
MORNING.
FOG WILL GRADUALLY DISSIPATE LATE THIS MORNING AND SKIES ARE
EXPECTED TO BECOME PARTLY TO MOSTLY SUNNY THIS AFTERNOON WITH
SUBSIDENCE UNDER THE HIGH PRESSURE RIDGE. IT WILL BECOME MILD AGAIN
TODAY WITH HIGH TEMPS REACHING THE MIDDLE TO UPPER 40S (00Z MET
NUMERICAL GUIDANCE MAXES ARE MUCH TOO COOL). THE HIGH PRESSURE RIDGE
WILL CONTINUE IN CONTROL OF THE WX PATTERN AND BRING FAIR WEATHER
THROUGH MONDAY.
.LONG TERM...(MONDAY NIGHT THROUGH FRIDAY)
ISSUED AT 320 AM EST SAT DEC 5 2015
THE SHORT STORY IS WARMER THAN NORMAL TEMPERATURES WILL BE FOLLOWED
MUCH WARMER THAN NORMAL TEMPERATURES LATER IN THE WEEK. WE WILL
TREND INTO A MUCH WETTER PATTERN AS WE HEAD TOWARD NEXT WEEKEND.
FOR THE MOST PART THE MODELS HAVE BEEN VERY CONSISTENT IN THE LARGE
SCALE DETAIL FOR THIS COMING WEEK. OUR VERY ACTIVE PACIFIC WAVE
TRAIN CONTINUES TO FEED SYSTEMS ON SHORE ABOUT EVERY TWO DAYS. WITH
THE SPLIT FLOW MOST OF THE PRECIPITATION HAS BEEN WELL NORTH IN
CANADA AND THIS COMING WEEK WE WILL SEE A LITTLE RAIN TRACK JUST
SOUTH OF MICHIGAN WITH THE SOUTHERN STREAM EARLY IN THE WEEK.
HOWEVER AS OUR VERY IMPRESSIVE 180 KNOT EAST ASIAN JET CORE (WE
HAVE BEEN FOLLOWING THIS ALL WEEK) GETS CLOSER TO WESTERN NORTH
AMERICA THE WAVES MOVING ON SHORE WILL AMPLIFY. THIS WILL
INCREASE THE FLOW OF GULF MOISTURE NORTH AND ALSO INCREASE JUST
HOW FAR NORTH THAT MOISTURE GETS.
IT SEEMS TO ME THE STORM NOW OFF THE WEST COAST (LOOKS GREAT ON THE
1 AM WATER VAPOR LOOPS...CHECK IT OUT OF YOU CAN) WILL BE OUR
WEDNESDAY SYSTEM. THIS ONE MAY HAVE ENOUGH WAVE LENGTH AS IT MOVES
TROUGH THE CENTRAL PLAINS TO GIVE US A FEW SHOWERS WEDNESDAY.
THERE WILL BE ONE MORE SYSTEM COMING THROUGH BEFORE THE SYSTEM WITH
THAT EAST ASIAN JET CORE OVER 180 KNOTS MOVES ONSHORE. THAT ONE
REACHES US IN THE FRIDAY TIME FRAME. THAT WILL BE MORE AMPLIFIED THAN
THE WEDNESDAY SYSTEM SO EXPECT A MORE WIDESPREAD RAIN EVENT WITH
THAT ONE.
MORE THAN LIKELY OUR TEMPERATURE FORECAST IS TO CONSERVATIVE... I
BELIEVE WE COULD SEE ACTUAL TEMPERATURE AS MUCH AS 5 TO 10 DEGREES
WARMER THAN WE ARE FORECASTING BY LATE IN THE PERIOD.
.WEEK TWO FORECAST...(SATURDAY THROUGH FRIDAY)
OF COURSE THE MAIN SHOW COMES THE NEXT WEEKEND INTO THE MIDDLE OF
THE FOLLOWING WEEK. BOTH THE ECMWF AND GFS SHOW THE AO AND NAO TENDING
TOWARD NEGATIVE VALUES THEN AND THE PNA GOING POSITIVE. ALL THAT
WOULD SUGGEST WESTERN RIDGE AND EASTERN TROUGH. THIS GOES WELL
WITH THE PROGRESSION OF THAT EAST ASIAN JET CORE. THE MAIN ENERGY
FOR THIS SYSTEM WILL COME TROUGH THE GREAT LAKES DURING THE
WEEKEND OF THE 12TH (SATURDAY). TIMING MAY BE SLOWER THAN I AM
SAYING BUT THE SYSTEM IN THE TIME FRAME OF SUNDAY THE 13TH COULD
BE A VERY DEEP SURFACE LOW WITH A LOT OF WIND AND A STRONG SURGE
OF EVERY WARM AIR. IT IS THIS SYSTEM THAT I THINK WILL BEING US
RECORD OR NEAR RECORD HIGHS IN THE MID 60S SATURDAY OR SUNDAY.
FOR THOSE WAITING FOR SNOW AND COLD... YOU MAY GET YOUR WISH BY THE
MIDDLE TO END OF THAT WEEK (THINK THE 15TH TO 18TH). THERE IS ONE
MORE SHORTWAVE THAT TRAILS THE MAIN SYSTEM. AS THAT MOVES INTO THE
PLAINS I DO BELIEVE WE WILL BE SEEING MUCH BETTER RIDGING OVER THE
WESTERN PLAINS AND MOUNTAIN STATES. THAT WILL FINALLY BRING IN 850
TEMPERATURES IN THE 15 BELOW RANGE INTO OUR AREA AND UNLIKE THE PAST
MONTH OR SO...THIS COLD PUSH WILL NOT LEAVE SO QUICKLY. THE GFS OUT
TO 16 DAYS HAS BEEN SHOWING THIS RUN AFTER RUN NOW FOR A WEEK. THE
CFSV2 ENSEMBLES SHOW SNOW COVER DOWN TO TENNESSEE BY FRIDAY THE
18TH. THIS HAS BEEN CONSISTENT IN THE CFSV2 FOR OVER A WEEK TOO.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1206 PM EST SAT DEC 5 2015
FOG WILL CONTINUE TO DISSIPATE LEADING TO MOSTLY VFR CONDITIONS BY
MID AFTERNOON. ANOTHER ROUND OF IMPACTFUL CONDITIONS IS LIKELY
FOR LATER TONIGHT. THERE ARE SOME INDICATIONS THAT THE FOG MAY NOT
BE AS WIDESPREAD OVERNIGHT INTO SUNDAY MORNING. THE PATTERN
HOWEVER HAS BEEN SUPPORTIVE OF FOG EACH NIGHT AND WILL CONTINUE TO
REFLECT THIS IN THE LASTEST FORECAST. CURRENT INDICATIONS ARE THAT
THE FOG WILL REDEVELOP AROUND KAZO AND KBTL BEFORE MIDNIGHT THEN
SPREAD/DEVELOP NORTH AND EAST AS THE NIGHT PROGRESSES.
&&
.MARINE...
ISSUED AT 1155 AM EST SAT DEC 5 2015
THE LATEST WAVE MODEL RUN INCORPORATING RUC WIND DATA THROUGH 18
HOURS IS INDICATING SOLID SMALL CRAFT ADVISORY CRITERIA WAVES
NORTH OF WHITEHALL THIS AFTERNOON AND TONIGHT. HAVE OPTED TO GO
AHEAD AND ISSUE A SCA NORTH OF WHITEHALL THROUGH 18Z ON SUNDAY.
THE WINDS SHOULD SUBSIDE CONSIDERABLY THROUGH THE COURSE OF THE
THE DAY ON SUNDAY AND THE WAVES WOULD DO IN KIND.
THE BIG SABLE POINT OBSERVATION SITE IS SHOWING WINDS GUSTING IN
EXCESS OF 18 KNOTS...WHICH IS A VALUE THAT OFTEN PRODUCES SCA
CRITERIA WAVES.
&&
.HYDROLOGY...
ISSUED AT 1152 AM EST FRI DEC 4 2015
RIVERS ARE WELL WITHIN BANKS AND FALLING. WITH LITTLE
PRECIPITATION EXPECTED UNTIL AT LEAST THE LATTER HALF OF NEXT
WEEK... FLOODING CONCERNS ARE MINIMAL.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 1 PM EST SUNDAY FOR LMZ848-849.
&&
$$
UPDATE...DUKE
SYNOPSIS...LAURENS
SHORT TERM...LAURENS
LONG TERM...WDM
AVIATION...MJS
HYDROLOGY...CAS
MARINE...DUKE
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
1206 PM EST SAT DEC 5 2015
.AVIATION...
ADVECTIVE FOG EVENT FROM LAST NIGHT LED TO AN AVIATION MESS
THIS MORNING. MOISTURE IS PRETTY SHALLOW BUT SOLIDLY LOCKED IN DUE
TO TREMENDOUS INVERSION WITH BASE AT ABOUT 300 FEET AGL. LOWER
ELEVATION AREAS SOUTH OF THE GLACIAL RIDGE ARE EXPERIENCING SLIGHT
UPSLOPE SURFACE FLOW THAT IS REINFORCING A BAD SITUATION. IT IS
ENTIRELY LIKELY THAT LOW CIGS ARE GOING TO PERSIST RIGHT THROUGH
THE NIGHT AS RAP SOUNDINGS KEEP STRONG INVERSION IN PLACE. FROM A
VBSY PERSPECTIVE WILL LIKELY SEE A SLIGHT DIURNAL RECOVERY FROM
LIFR TO IFR FOR THE LATTER HALF OF THE AFTERNOON... BUT LATEST HRRR
RUNS STRONGLY SUGGEST SOCKING BACK IN SHORTLY AFTER SUNSET. NORTH OF
THE RIDGE... THINGS ARE QUICKLY IMPROVING LATE THIS MORNING AT PTK..
FNT.. AND MBS. THESE LOCATIONS SHOULD ALL BE VFR AROUND 18-19Z.
AGAIN THOUGH... HRRR RUNS ARE HINTING AT AN ADVECTIVE PUSH
NORTHWARD OF LOW CIGS AND FOG THIS EVENING SO BROUGHT LIFR
CONDITIONS IN AGAIN BY 01-04Z.
FOR DTW...TRENDS AND MODELS ARE INCREASING CONFIDENCE THAT
PROLONGED PERIOD OF LIFR/IFR VSBY WILL IMPACT METRO THROUGH THE NEXT
20 OR SO HOURS. STEEP PERSISTENT LOW LEVEL INVERSION... WEAK
UPSLOPE... AND LOW DECEMBER SUN ANGLE ALL CONSPIRING TO LOCK IN POOR
CONDITIONS. AGAIN... SLIGHT DIURNAL TRENDS COULD IMPROVE VSBY TO 1-3
NILES FOR A FEW HOURS THIS AFTERNOON BEFORE LOWERING AGAIN WITH
SUNSET.
//DTW THRESHOLD PROBABILITIES...
* HIGH CONFIDENCE CEILINGS WILL BE BELOW 5000 FT THROUGH SUNDAY
MORNING.
* HIGH CONFIDENCE IN CIGS AT OR BELOW 200 FT THROUGH 20Z TODAY AND
AGAIN FROM 00Z TO 16Z SUNDAY.
* MODERATE TO HIGH CONFIDENCE IN VSBY 1/2 MILES OR LESS THROUGH 20Z
TODAY AND AGAIN FROM 00Z TO 16Z SUNDAY.
&&
.PREV DISCUSSION...ISSUED 547 AM EST SAT DEC 5 2015
UPDATE...
WILL UPDATE TO CANCEL THE DENSE FOG ADVISORY OVER THE SAGINAW
VALLEY WHERE 5 TO 10 MPH SOUTHWEST GRADIENT FLOW IS HELPING TO
MITIGATE THE FORMATION OF DENSE FOG AS VISIBILITIES ARE HOLDING
MORE IN THE 2 TO 5 MILE RANGE.
ELSEWHERE...DENSE FOG CONTINUES TO SLOWLY EXPAND ACROSS THE REGION
AND EXPECT THIS TREND TO CONTINUE UNTIL BETWEEN 8 AND 9 AM. IT
WILL THEN TAKE MOST OF THE MORNING FOR THIS FOG TO BURN OFF. IN
FACT...PARTLY TO MOSTLY CLEAR SKIES WILL MOST LIKELY HOLD OFF
UNTIL MID AFTERNOON IN SOME LOCATIONS. FOR THIS REASON...WILL ALSO
LOWER HIGH TEMPERATURES A BIT MORE WITH HIGHS IN THE LOWER TO MID
40S EXPECTED.
PREV DISCUSSION...ISSUED 335 AM EST SAT DEC 5 2015
DISCUSSION...
LARGE AREA OF STRATUS CONTINUES TO BUILD EAST AND NORTHEAST OVER
AREA EARLY THIS MORNING AND EXPECT THIS TREND TO PERSIST THROUGH
SUNRISE OR A BIT LATER...LEADING TO GENERALLY CLOUDY SKIES ACROSS
THE ENTIRE FORECAST AREA BY DAYBREAK. THIS MOISTURE IS TRAPPED UNDER
A VERY SHALLOW LOW LEVEL INVERSION WITH CEILINGS ON THE ORDER OF 100
TO 200 FEET. THIS MOISTURE EXTENDS TO THE BOUNDARY LAYER SO ALSO
EXPECT THE AREAS OF DENSE FOG NOTED WITHIN STRATUS FIELD TO EXPAND
ACROSS AREA. THIS WILL REQUIRE A DENSE FOG ADVISORY FOR ALL OR MOST
OF SOUTHEAST LOWER MICHIGAN AS VISIBILITY AT OR BELOW ON QUARTER OF
A MILE WILL BECOME MORE WIDESPREAD DURING THE REMAINDER OF THE
OVERNIGHT AND EARLY MORNING HOURS.
WITH A WEAK LOW LEVEL FLOW...EXPECT IT WILL TAKE A WHILE FOR THIS
MOISTURE TO MIX OUT...SO MOSTLY CLOUDY SKIES THIS MORNING WILL
GRUDGINGLY BECOME PARTLY CLOUDY DURING THE AFTERNOON. THIS WILL
LIMIT OVERALL HEATING...AND WILL LOWER MAXIMUM TEMPERATURES SEVERAL
DEGREES TODAY...WITH HIGHS TENTATIVELY EXPECTED TO REACH THE MIDDLE
40S BY MID/LATE AFTERNOON.
HEADING THROUGH LATE THIS WEEKEND ON THROUGH THE UPCOMING WEEK...IT
APPEARS A RATHER MILD PERIOD OF WEATHER IS SETTING UP OVER THE GREAT
LAKES. JET STREAM ENERGY OVER THE PACIFIC OCEAN WILL EXPAND EASTWARD
OVER THE CONUS AND ACT TO TRAP COLDER CANADIAN AIR WELL NORTH OF THE
CONUS/CANADIAN BORDER...BASICALLY FOR THE BALANCE OF THIS FORECAST
PERIOD.
WITH TIME...THE MILD AIRMASS MOVING OVER THE CONUS FROM THE
PACIFIC WILL COMBINED WITH INCREASED SOUTH/SOUTHWEST FLOW FROM THE
GULF STATES TO BRING A PERIOD OF WELL ABOVE AVERAGE TEMPERATURES.
ABOUT THE ONLY FACTOR NEGATING FROM THIS TREND WILL BE EXTENSIVE
CLOUD COVER AT TIMES...BUT GIVEN THE OVERALL WARMTH OF THE AIRMASS
THAT WILL BE IN PLACE...FEEL CONFIDENT THAT TEMPERATURES WILL
AVERAGE NEARLY 10F ABOVE AVERAGE FOR A GOOD PART OF THE UPCOMING
WEEK WITH MODERATING TEMPERATURES ON INTO NEXT WEEKEND AS UPPER
RIDGING EXPANDS OVER THE EASTERN CONUS IN RESPONSE TO AN AMPLIFYING
UPPER TROUGH OUT WEST AS THE STEADY STREAM OF PACIFIC JET ENERGY
ACTS TO BUCKLE THE UPPER LEVEL FLOW.
IN GENERAL TERMS...THIS SUGGESTS WIDESPREAD TEMPERATURES IN THE 40S
EARLY IN THE WEEK MODERATE FURTHER INTO THE 50S AT TIMES BY LATE IN
THE FORECAST PERIOD. WHILE NO STRONG STORM SYSTEM IS NOTED AT THIS
TIME...SHOWERS WILL BECOME INCREASINGLY LIKELY AS THIS MILD AND
MOIST AIRMASS STEADILY EXPANDS INTO THE AREA...AND BITS OF SHORTWAVE
ENERGY BEGIN TO EJECT INTO AREA FROM DEEPENING UPPER TROUGH TO THE
WEST.
MARINE...
STRONG HIGH PRESSURE OVER THE UPPER OHIO VALLEY AND MID ATLANTIC
WILL SUSTAIN SOUTHWEST WINDS ACROSS THE LAKES TODAY INTO SUNDAY.
VERY WARM AIR ATOP THE LAKE SURFACE WILL HINDER MIXING...SO WINDS
SHOULD REMAIN MAINLY IN THE 10 TO 15 KNOT RANGE WITH GUSTS HOLDING
BELOW 20 KNOTS. THE GRADIENT WILL RELAX OVER THE REGION BY
MONDAY...LEADING TO LIGHT WINDS TO START THE WEEK. THE RELATIVE WARM
LAKE TEMPERATURES SHOULD KEEP FOG AT BAY...ALTHOUGH SOME OF THE
PORTS MAY BE IMPACTED BY SOME FOG THIS MORNING AND SUNDAY MORNING.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MICHIGAN WATERS OF LAKE ERIE...NONE.
&&
$$
AVIATION.....05
UPDATE.......DG
DISCUSSION....DG
MARINE.......SC
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1155 AM EST SAT DEC 5 2015
LATEST UPDATE...
UPDATE/MARINE
.SYNOPSIS...
ISSUED AT 320 AM EST SAT DEC 5 2015
HIGH PRESSURE WILL PRODUCE FAIR AND MILD WEATHER THROUGH THE
WEEKEND. HOWEVER AREAS OF DENSE FOG THIS MORNING WILL CAUSE
HAZARDOUS TRAVEL CONDITIONS. TEMPERATURES WILL CONTINUE TO AVERAGE
AT LEAST TEN TO FIFTEEN DEGREES ABOVE NORMAL THROUGH THE UPCOMING
WEEK.
&&
.UPDATE...
ISSUED AT 1155 AM EST SAT DEC 5 2015
WILL BE DROPPING THE DENSE FOG ADVISORY AS VISIBILITIES HAVE
IMPROVED LATE THIS MORNING. ALL REPORTING STATIONS ACROSS THE GRR
FORECAST AREA NOW HAVE AT LEAST A 1/2 MILE VISIBILITY. A
SIGNIFICANT IMPROVEMENT FROM EARLIER WHERE VISIBILITY WAS BETWEEN
ZERO AND A 1/4 MILE IN MANY AREAS.
THIS AFTERNOON...THE VERY SHALLOW STRATUS SHOULD ERODE AND SKIES
SHOULD TURN MOSTLY SUNNY AS WE WORK THROUGH THE AFTERNOON. HIGH
TEMPERATURES WILL TOP OUT IN THE MIDDLE TO UPPER 40S.
&&
.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 320 AM EST SAT DEC 5 2015
A FREEZING FOG ADVISORY REMAINS IN EFFECT FOR ALL OF OUR FCST AREA
THROUGH 15Z THIS MORNING. SFC OBS/GROUND TRUTH REPORTS CONTINUE TO
INDICATE AREAS OF DENSE FOG ACROSS MUCH OF OUR FCST AREA. THIS IN
CONJUNCTION WITH SFC TEMPS AT OR BELOW FREEZING ACROSS PORTIONS OF
OUR AREA WILL RESULT IN HAZARDOUS TRAVEL CONDITIONS THROUGH MID
MORNING.
FOG WILL GRADUALLY DISSIPATE LATE THIS MORNING AND SKIES ARE
EXPECTED TO BECOME PARTLY TO MOSTLY SUNNY THIS AFTERNOON WITH
SUBSIDENCE UNDER THE HIGH PRESSURE RIDGE. IT WILL BECOME MILD AGAIN
TODAY WITH HIGH TEMPS REACHING THE MIDDLE TO UPPER 40S (00Z MET
NUMERICAL GUIDANCE MAXES ARE MUCH TOO COOL). THE HIGH PRESSURE RIDGE
WILL CONTINUE IN CONTROL OF THE WX PATTERN AND BRING FAIR WEATHER
THROUGH MONDAY.
.LONG TERM...(MONDAY NIGHT THROUGH FRIDAY)
ISSUED AT 320 AM EST SAT DEC 5 2015
THE SHORT STORY IS WARMER THAN NORMAL TEMPERATURES WILL BE FOLLOWED
MUCH WARMER THAN NORMAL TEMPERATURES LATER IN THE WEEK. WE WILL
TREND INTO A MUCH WETTER PATTERN AS WE HEAD TOWARD NEXT WEEKEND.
FOR THE MOST PART THE MODELS HAVE BEEN VERY CONSISTENT IN THE LARGE
SCALE DETAIL FOR THIS COMING WEEK. OUR VERY ACTIVE PACIFIC WAVE
TRAIN CONTINUES TO FEED SYSTEMS ON SHORE ABOUT EVERY TWO DAYS. WITH
THE SPLIT FLOW MOST OF THE PRECIPITATION HAS BEEN WELL NORTH IN
CANADA AND THIS COMING WEEK WE WILL SEE A LITTLE RAIN TRACK JUST
SOUTH OF MICHIGAN WITH THE SOUTHERN STREAM EARLY IN THE WEEK.
HOWEVER AS OUR VERY IMPRESSIVE 180 KNOT EAST ASIAN JET CORE (WE
HAVE BEEN FOLLOWING THIS ALL WEEK) GETS CLOSER TO WESTERN NORTH
AMERICA THE WAVES MOVING ON SHORE WILL AMPLIFY. THIS WILL
INCREASE THE FLOW OF GULF MOISTURE NORTH AND ALSO INCREASE JUST
HOW FAR NORTH THAT MOISTURE GETS.
IT SEEMS TO ME THE STORM NOW OFF THE WEST COAST (LOOKS GREAT ON THE
1 AM WATER VAPOR LOOPS...CHECK IT OUT OF YOU CAN) WILL BE OUR
WEDNESDAY SYSTEM. THIS ONE MAY HAVE ENOUGH WAVE LENGTH AS IT MOVES
TROUGH THE CENTRAL PLAINS TO GIVE US A FEW SHOWERS WEDNESDAY.
THERE WILL BE ONE MORE SYSTEM COMING THROUGH BEFORE THE SYSTEM WITH
THAT EAST ASIAN JET CORE OVER 180 KNOTS MOVES ONSHORE. THAT ONE
REACHES US IN THE FRIDAY TIME FRAME. THAT WILL BE MORE AMPLIFIED THAN
THE WEDNESDAY SYSTEM SO EXPECT A MORE WIDESPREAD RAIN EVENT WITH
THAT ONE.
MORE THAN LIKELY OUR TEMPERATURE FORECAST IS TO CONSERVATIVE... I
BELIEVE WE COULD SEE ACTUAL TEMPERATURE AS MUCH AS 5 TO 10 DEGREES
WARMER THAN WE ARE FORECASTING BY LATE IN THE PERIOD.
.WEEK TWO FORECAST...(SATURDAY THROUGH FRIDAY)
OF COURSE THE MAIN SHOW COMES THE NEXT WEEKEND INTO THE MIDDLE OF
THE FOLLOWING WEEK. BOTH THE ECMWF AND GFS SHOW THE AO AND NAO TENDING
TOWARD NEGATIVE VALUES THEN AND THE PNA GOING POSITIVE. ALL THAT
WOULD SUGGEST WESTERN RIDGE AND EASTERN TROUGH. THIS GOES WELL
WITH THE PROGRESSION OF THAT EAST ASIAN JET CORE. THE MAIN ENERGY
FOR THIS SYSTEM WILL COME TROUGH THE GREAT LAKES DURING THE
WEEKEND OF THE 12TH (SATURDAY). TIMING MAY BE SLOWER THAN I AM
SAYING BUT THE SYSTEM IN THE TIME FRAME OF SUNDAY THE 13TH COULD
BE A VERY DEEP SURFACE LOW WITH A LOT OF WIND AND A STRONG SURGE
OF EVERY WARM AIR. IT IS THIS SYSTEM THAT I THINK WILL BEING US
RECORD OR NEAR RECORD HIGHS IN THE MID 60S SATURDAY OR SUNDAY.
FOR THOSE WAITING FOR SNOW AND COLD... YOU MAY GET YOUR WISH BY THE
MIDDLE TO END OF THAT WEEK (THINK THE 15TH TO 18TH). THERE IS ONE
MORE SHORTWAVE THAT TRAILS THE MAIN SYSTEM. AS THAT MOVES INTO THE
PLAINS I DO BELIEVE WE WILL BE SEEING MUCH BETTER RIDGING OVER THE
WESTERN PLAINS AND MOUNTAIN STATES. THAT WILL FINALLY BRING IN 850
TEMPERATURES IN THE 15 BELOW RANGE INTO OUR AREA AND UNLIKE THE PAST
MONTH OR SO...THIS COLD PUSH WILL NOT LEAVE SO QUICKLY. THE GFS OUT
TO 16 DAYS HAS BEEN SHOWING THIS RUN AFTER RUN NOW FOR A WEEK. THE
CFSV2 ENSEMBLES SHOW SNOW COVER DOWN TO TENNESSEE BY FRIDAY THE
18TH. THIS HAS BEEN CONSISTENT IN THE CFSV2 FOR OVER A WEEK TOO.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 710 AM EST SAT DEC 5 2015
THE BIG QUESTION FOR TODAY IS WILL THE FOG REALLY BREAK UP TODAY?
THE LATEST RUN OF THE RAP MODEL (11Z) SHOWS THE FOG BREAKING UP AT
GRR..BTL AND LAN BY 19Z OR SO BUT HOLDING IN AT JXN AND AZO. GIVEN
WE HAVE SOUTH WINDS AT THE SURFACE AND THE FOG GOES SOUTH INTO
NORTHERN KENTUCKY AND THAT THIS IS DECEMBER...THIS FOG MAY WELL
LAST INTO THIS AFTERNOON. I WENT WITH THE IDEA THE FOG WOULD BREAK
UP AT ALL TAF SITES BY EARLY AFTERNOON BUT I WILL ADMIT THAT WAS
AN OPTIMIST FORECAST.
THERE IS AN ISSUE WITH THE FOG COMING BACK TONIGHT. THE LATEST RUN
OF THEN NAM SHOWS 20 TO 25 KNOT WINDS IN THE BOUNDARY LAYER
BETWEEN 03Z AND 09Z BUT THOSE WINDS LET UP AFTER 09Z. IT MAY WELL
BE THAT IS A BIG ENOUGH WINDOW...GIVEN IT IS DECEMBER TO THAT
DENSE FOG TO COME BACK. SO I DID BRING DENSE FOG IN TOWARD SUNDAY
MORNING.
&&
.MARINE...
ISSUED AT 1155 AM EST SAT DEC 5 2015
THE LATEST WAVE MODEL RUN INCORPORATING RUC WIND DATA THROUGH 18
HOURS IS INDICATING SOLID SMALL CRAFT ADVISORY CRITERIA WAVES
NORTH OF WHITEHALL THIS AFTERNOON AND TONIGHT. HAVE OPTED TO GO
AHEAD AND ISSUE A SCA NORTH OF WHITEHALL THROUGH 18Z ON SUNDAY.
THE WINDS SHOULD SUBSIDE CONSIDERABLY THROUGH THE COURSE OF THE
THE DAY ON SUNDAY AND THE WAVES WOULD DO IN KIND.
THE BIG SABLE POINT OBSERVATION SITE IS SHOWING WINDS GUSTING IN
EXCESS OF 18 KNOTS...WHICH IS A VALUE THAT OFTEN PRODUCES SCA
CRITERIA WAVES.
&&
.HYDROLOGY...
ISSUED AT 1152 AM EST FRI DEC 4 2015
RIVERS ARE WELL WITHIN BANKS AND FALLING. WITH LITTLE
PRECIPITATION EXPECTED UNTIL AT LEAST THE LATTER HALF OF NEXT
WEEK... FLOODING CONCERNS ARE MINIMAL.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 1 PM EST SUNDAY FOR LMZ848-849.
&&
$$
UPDATE...DUKE
SYNOPSIS...LAURENS
SHORT TERM...LAURENS
LONG TERM...WDM
AVIATION...WDM
HYDROLOGY...CAS
MARINE...DUKE
AREA FORECAST DISCUSSION
NWS DULUTH MN
324 PM CST SAT DEC 5 2015
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 240 PM CST SAT DEC 5 2015
HAVE INCREASED COVERAGE OF DRIZZLE AND INTRODUCED PATCHY FOG
OVERNIGHT AS FORECAST AREA REMAINS IN WARM SECTOR AHEAD OF 850HPA
TROUGH. A BROAD AREA OF LOW CLOUDS HAS DEVELOPED IN THE WARM AIR
ADVECTION REGIME AHEAD OF THE BOUNDARY. EXPECT CEILINGS TO
CONTINUE TO LOWER THROUGH THE EVENING WITH COOLING TEMPS AND
DEVELOPING PATCHY FOG AND DRIZZLE IN THE LATE EVENING AND
OVERNIGHT. CARRIED CLOUD COVER LONGER INTO SUNDAY MORNING FOR A
SLIGHTLY SLOWER TIMING OF THE FRONTAL PASSAGE AND CLEARING WITH
THE BUILDING RIDGE. TEMPERATURES WILL AGAIN BE MILD...WARMING INTO
THE UPPER 30S TO AROUND 40F.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 240 PM CST SAT DEC 5 2015
PLENTY OF UNCERTAINTY EXISTS THROUGH THE EXTENDED PERIOD WITH
SEVERAL LOW PRESSURE SYSTEMS IMPACTING THE NORTHLAND. THE
UNCERTAINTY STARTS TO RAMP UP AFTER MONDAY AND IS MOST PRONOUNCED
WITH A LATE WEEK/WEEKEND SYSTEM.
A QUASI ZONAL FLOW ALOFT WILL START OFF THE PERIOD WITH A MILD
SOUTHERLY FLOW KEEPING THE REGION DRY SUNDAY NIGHT INTO MONDAY
NIGHT. A SHORTWAVE WILL MOVE THROUGH THE AREA TUESDAY/TUESDAY NIGHT.
PRECIP TYPE WILL BE AN ISSUE WITH WARM AIR IN PLACE. AT THIS
TIME...WE WENT WITH RAIN TUESDAY...AND RAIN OR SNOW TUESDAY NIGHT.
DEPENDING ON THE TIMING OF THE PRECIPITATION...THERE COULD BE A
PERIOD OF LIGHT FREEZING DRIZZLE/RAIN. THE PRECIPITATION AMOUNTS
LOOK TO BE MAINLY LIGHT WITH THIS FIRST SYSTEM.
BOTH THE GFS AND ECMWF BRING A SECOND LOW PRESSURE SYSTEM INTO THE
REGION WEDNESDAY NIGHT INTO THURSDAY NIGHT. THE GFS IS FASTER THAN
THE ECMWF AND TRACKS THE SURFACE LOW A BIT FURTHER NORTH. A WINTRY
MIX WILL AGAIN BE POSSIBLE DUE TO WARM AIR STILL IN PLACE. THE ECMWF
IS SLOWER MOVING THE LOW THROUGH AND IS MORE BULLISH WITH ITS
QPF...ESPECIALLY OVER NORTHERN MINNESOTA.
THE GFS BRINGS IN AN AREA OF LOW PRESSURE TO SOUTHERN MINNESOTA BY
FRIDAY NIGHT...WITH THE ECMWF MUCH DIFFERENT DUE TO IT BEING BEING
SLOWER AND STRONGER WITH THE PREVIOUS LOW. BY 00Z SUNDAY...THE
GFS HAS A LOW JUST NORTH OF WESTERN LAKE SUPERIOR WITH THE ECMWF
SHOWING THE LOW STILL OVER THE CENTRAL PLAINS. MORE SNOW OR A WINTRY
MIX WILL BE POSSIBLE LATE IN THE WEEK INTO THE WEEKEND.
THE ONE THING THAT SEEMS MORE CERTAIN THROUGH THE EXTENDED IS THAT
HIGH TEMPERATURES SHOULD REMAIN ABOVE NORMAL THROUGH MOST OF THE
PERIOD.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1205 PM CST SAT DEC 5 2015
AN MVFR DECK HAS DEVELOPED AHEAD OF A COLD FRONT MOVING INTO THE
FORECAST AREA FROM THE EASTERN DAKOTAS. THE LATEST RAP AND NAM
HAVE A PRETTY GOOD HANDLE ON THIS MVFR DECK MOVING IN...SO LEANED
TOWARDS THIS GUIDANCE IN THE LATEST TAF SET. AS THE FRONT MOVES
THROUGH EXPECTING SPOTTY SHOWERS OR DRIZZLE TO DEVELOP THIS
EVENING. THE COMBINATION OF MILD TEMPERATURES...LIGHT
WINDS...PRECIPITATION AND MELTING SNOW WILL RESULT IN FOG
DEVELOPING AT ALL TERMINALS THIS EVENING AND OVERNIGHT. THIS WILL
RESULT IN IFR CIGS/VISBY DEVELOPING TONIGHT INTO SUNDAY MORNING.
SUSPECT KHYR COULD SEE LIFR CONDITIONS...HOWEVER UNCERTAIN ON WHEN
EXACTLY THIS WILL OCCUR AT THIS POINT IN TIME. AFTER THE FRONT
PASSES...EXPECTING VFR CONDITIONS TO RETURN AFTER 10-12Z AT ALL
LOCATIONS EXCEPT FOR KHYR WHERE THE LOW CLOUDS AND FOG MAY
LINGER.
&&
.PRELIMINARY POINT TEMPS/POPS...
DLH 33 41 25 40 / 20 10 0 0
INL 27 39 22 41 / 10 0 0 0
BRD 29 41 24 42 / 10 10 0 0
HYR 34 42 22 43 / 20 20 0 0
ASX 35 43 24 43 / 20 20 0 0
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
LS...SMALL CRAFT ADVISORY UNTIL 10 PM CST THIS EVENING FOR LSZ121-140-
141-146>148.
&&
$$
SHORT TERM...GRANING
LONG TERM...MELDE
AVIATION...WL
AREA FORECAST DISCUSSION
NWS DULUTH MN
1205 PM CST SAT DEC 5 2015
.UPDATE...
ISSUED AT 1000 AM CST SAT DEC 5 2015
HAVE INCREASED TEMPS TODAY AS THE 50KT LLJ HAS KEPT A WARM
SOUTHERLY FLOW OVER THE REGION. LATEST SATELLITE IMAGERY SHOWS
MOSTLY SUNNY SKIES CURRENTLY OVER THE NORTHLAND. AN AREA OF HIGH
CLOUDS WAS COVERING SOUTHWEST MINNESOTA...PUSHING TOWARDS THE
NORTHEAST. THERE IS STILL SOME UNCERTAINTY IN THE LOW CLOUD
DEVELOPMENT ALONG AN 800HPA TROUGH SITUATED IN CENTRAL MN.
ALTHOUGH LATEST BUFR SOUNDINGS SHOW THE LOW LEVEL MOISTURE IS
LIMITED TO A VERY SHALLOW NEAR BOUNDARY LAYER...A FEW STATIONS IN
NORTH CENTRAL MN ARE STARTING TO REPORT FEW CLOUDS AROUND 20 KFT.
&&
.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 351 AM CST SAT DEC 5 2015
MINNESOTA IS IN A WARM SECTOR AHEAD OF A COLD FRONT EXTENDING NORTH-
SOUTH ACROSS THE DAKOTAS FROM A SURFACE LOW OVER NORTHERN MANITOBA.
THE WARM SECTOR IS QUITE MILD...WITH SURFACE TEMPERATURES IN THE
MIDDLE AND UPPER 30S ACROSS MOST OF NORTHERN MINNESOTA AND
WISCONSIN. BEHIND THE COLD FRONT IS NOT DRAMATICALLY COLDER BUT
TEMPERATURES DO FALL INTO THE UPPER 20S AND LOWER 30S FAIRLY
QUICKLY. THIS COLD FRONT TO SLOWLY MOVE INTO THE FORECAST AREA
TODAY...BECOMING MORE AND MORE DIFFUSE AS IT MOVES EAST TONIGHT AND
EARLY SUNDAY. THIS FEATURE TO BE A FOCUS FOR MID LEVEL MOISTURE TO
STREAM UP INTO THE AREA AND WITH SOME WEAK LIFT ALONG THE BOUNDARY
HAVE PUT IN SOME SHOWERS TONIGHT AND EARLY SUNDAY MORNING. MODELS
ARE TRYING TO PUT IN A NEARLY SATURATED BOUNDARY LAYER...BUT HAVE
SIGNIFICANT CONCERNS ON THIS AS CURRENT MODEL SOUNDINGS ARE OVER
SATURATED AND TOO COLD AT THE SURFACE NOW...AND ONLY GET WORSE IN
THE NEXT 24 HOURS. IN ADDITION THERE IS NO SIGN OF OF STRATUS IN
THE UPSTREAM AIRMASS OVER NORTH DAKOTA AND SOUTHERN
MANITOBA/SASKATCHEWAN...AND WOULD PREFER TO SEE SOME SIGNS OF IT
THERE BY NOW. WE HAVE ALSO SEEN A PATTERN RECENTLY OF THE MODELS
OVERDOING THE LOW LEVEL MOISTURE IN THIS PATTERN. THUS...HAVE
SWITCHED THE FORECAST OVER TO SLIGHT CHANCES OF SHOWERS. WITH THE
CLOUD COVER AROUND HAVE ALSO REDUCED THE DIURNAL RANGE AND BROUGHT
UP THE MIN TEMPS IN THE VICINITY OF THE FRONT FOR MAINLY LIQUID
SHOWERS IN THE EVENING... TRANSITIONING TO SNOW OVERNIGHT.
.LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY)
ISSUED AT 351 AM CST SAT DEC 5 2015
THE LONG TERM IS STARTING TO SOUND LIKE A BROKEN RECORD...AS
UNSEASONABLY WARM WEATHER IS EXPECTED TO CONTINUE THROUGHOUT THE
PERIOD. UPPER LEVEL RIDGING SUNDAY NIGHT AND EARLY MONDAY WILL BRING
A QUIET AND WARM START TO THE WORK WEEK. WITH A GOOD DEAL OF
SUNSHINE...TEMPERATURES SHOULD TOP OUT IN THE 39 TO 44 DEGREE RANGE.
TO PUT THAT IN PERSPECTIVE...NORMAL HIGH TEMPERATURES FOR THIS TIME
OF YEAR ARE GENERALLY IN THE LOW TO MID 20S. THE UPPER LEVEL FLOW
WILL THEN QUICKLY TRANSITION TO A QUASI-ZONAL FLOW BY MONDAY AND
MONDAY NIGHT...WITH A SHORTWAVE PUSHING EASTWARD ACROSS THE CWA
LATER TUESDAY AND TUESDAY NIGHT. WILL MENTION SOME SMALL POPS
REGARDING THIS SYSTEM BUT BEST CHANCE LOOKS TO BE SOUTH OF THE CWA.
THE MODELS ONCE AGAIN START TO DIVERGE FROM WEDNESDAY INTO FRIDAY OF
NEXT WEEK...SO THE CONFIDENCE IN ANY PARTICULAR SOLUTION CONTINUES
TO BE LOWER THAN AVERAGE. IN TERMS OF SENSIBLE WEATHER THE IMPACT IS
NOT TOO GREAT...AS IT DOES LOOK LIKE PRECIPITATION CHANCES WILL
EXIST NO MATTER WHICH MODEL...AND TEMPS APPEAR TO CONTINUE ABOVE
NORMAL. THROUGHOUT THE PERIOD WE SHOULD SEE HIGH TEMPERATURES RANGE
FROM THE MID 30S TO THE MID 40S...WITH LOWS IN THE 20S TO 30S.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1205 PM CST SAT DEC 5 2015
AN MVFR DECK HAS DEVELOPED AHEAD OF A COLD FRONT MOVING INTO THE
FORECAST AREA FROM THE EASTERN DAKOTAS. THE LATEST RAP AND NAM
HAVE A PRETTY GOOD HANDLE ON THIS MVFR DECK MOVING IN...SO LEANED
TOWARDS THIS GUIDANCE IN THE LATEST TAF SET. AS THE FRONT MOVES
THROUGH EXPECTING SPOTTY SHOWERS OR DRIZZLE TO DEVELOP THIS
EVENING. THE COMBINATION OF MILD TEMPERATURES...LIGHT
WINDS...PRECIPITATION AND MELTING SNOW WILL RESULT IN FOG
DEVELOPING AT ALL TERMINALS THIS EVENING AND OVERNIGHT. THIS WILL
RESULT IN IFR CIGS/VISBY DEVELOPING TONIGHT INTO SUNDAY MORNING.
SUSPECT KHYR COULD SEE LIFR CONDITIONS...HOWEVER UNCERTAIN ON WHEN
EXACTLY THIS WILL OCCUR AT THIS POINT IN TIME. AFTER THE FRONT
PASSES...EXPECTING VFR CONDITIONS TO RETURN AFTER 10-12Z AT ALL
LOCATIONS EXCEPT FOR KHYR WHERE THE LOW CLOUDS AND FOG MAY
LINGER.
&&
.PRELIMINARY POINT TEMPS/POPS...
DLH 46 32 42 27 / 10 20 0 0
INL 44 27 39 25 / 10 0 0 0
BRD 43 28 41 24 / 10 10 0 0
HYR 47 34 42 22 / 10 20 0 0
ASX 49 35 43 25 / 10 20 0 0
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
LS...SMALL CRAFT ADVISORY UNTIL 10 PM CST THIS EVENING FOR LSZ121-140-
141-146>148.
&&
$$
UPDATE...GRANING
SHORT TERM...LE
LONG TERM...DAP
AVIATION...WL
AREA FORECAST DISCUSSION
NWS DULUTH MN
1016 AM CST SAT DEC 5 2015
.UPDATE...
ISSUED AT 1000 AM CST SAT DEC 5 2015
HAVE INCREASED TEMPS TODAY AS THE 50KT LLJ HAS KEPT A WARM
SOUTHERLY FLOW OVER THE REGION. LATEST SATELLITE IMAGERY SHOWS
MOSTLY SUNNY SKIES CURRENTLY OVER THE NORTHLAND. AN AREA OF HIGH
CLOUDS WAS COVERING SOUTHWEST MINNESOTA...PUSHING TOWARDS THE
NORTHEAST. THERE IS STILL SOME UNCERTAINTY IN THE LOW CLOUD
DEVELOPMENT ALONG AN 800HPA TROUGH SITUATED IN CENTRAL MN.
ALTHOUGH LATEST BUFR SOUNDINGS SHOW THE LOW LEVEL MOISTURE IS
LIMITED TO A VERY SHALLOW NEAR BOUNDARY LAYER...A FEW STATIONS IN
NORTH CENTRAL MN ARE STARTING TO REPORT FEW CLOUDS AROUND 20 KFT.
&&
.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 351 AM CST SAT DEC 5 2015
MINNESOTA IS IN A WARM SECTOR AHEAD OF A COLD FRONT EXTENDING NORTH-
SOUTH ACROSS THE DAKOTAS FROM A SURFACE LOW OVER NORTHERN MANITOBA.
THE WARM SECTOR IS QUITE MILD...WITH SURFACE TEMPERATURES IN THE
MIDDLE AND UPPER 30S ACROSS MOST OF NORTHERN MINNESOTA AND
WISCONSIN. BEHIND THE COLD FRONT IS NOT DRAMATICALLY COLDER BUT
TEMPERATURES DO FALL INTO THE UPPER 20S AND LOWER 30S FAIRLY
QUICKLY. THIS COLD FRONT TO SLOWLY MOVE INTO THE FORECAST AREA
TODAY...BECOMING MORE AND MORE DIFFUSE AS IT MOVES EAST TONIGHT AND
EARLY SUNDAY. THIS FEATURE TO BE A FOCUS FOR MID LEVEL MOISTURE TO
STREAM UP INTO THE AREA AND WITH SOME WEAK LIFT ALONG THE BOUNDARY
HAVE PUT IN SOME SHOWERS TONIGHT AND EARLY SUNDAY MORNING. MODELS
ARE TRYING TO PUT IN A NEARLY SATURATED BOUNDARY LAYER...BUT HAVE
SIGNIFICANT CONCERNS ON THIS AS CURRENT MODEL SOUNDINGS ARE OVER
SATURATED AND TOO COLD AT THE SURFACE NOW...AND ONLY GET WORSE IN
THE NEXT 24 HOURS. IN ADDITION THERE IS NO SIGN OF OF STRATUS IN
THE UPSTREAM AIRMASS OVER NORTH DAKOTA AND SOUTHERN
MANITOBA/SASKATCHEWAN...AND WOULD PREFER TO SEE SOME SIGNS OF IT
THERE BY NOW. WE HAVE ALSO SEEN A PATTERN RECENTLY OF THE MODELS
OVERDOING THE LOW LEVEL MOISTURE IN THIS PATTERN. THUS...HAVE
SWITCHED THE FORECAST OVER TO SLIGHT CHANCES OF SHOWERS. WITH THE
CLOUD COVER AROUND HAVE ALSO REDUCED THE DIURNAL RANGE AND BROUGHT
UP THE MIN TEMPS IN THE VICINITY OF THE FRONT FOR MAINLY LIQUID
SHOWERS IN THE EVENING... TRANSITIONING TO SNOW OVERNIGHT.
.LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY)
ISSUED AT 351 AM CST SAT DEC 5 2015
THE LONG TERM IS STARTING TO SOUND LIKE A BROKEN RECORD...AS
UNSEASONABLY WARM WEATHER IS EXPECTED TO CONTINUE THROUGHOUT THE
PERIOD. UPPER LEVEL RIDGING SUNDAY NIGHT AND EARLY MONDAY WILL BRING
A QUIET AND WARM START TO THE WORK WEEK. WITH A GOOD DEAL OF
SUNSHINE...TEMPERATURES SHOULD TOP OUT IN THE 39 TO 44 DEGREE RANGE.
TO PUT THAT IN PERSPECTIVE...NORMAL HIGH TEMPERATURES FOR THIS TIME
OF YEAR ARE GENERALLY IN THE LOW TO MID 20S. THE UPPER LEVEL FLOW
WILL THEN QUICKLY TRANSITION TO A QUASI-ZONAL FLOW BY MONDAY AND
MONDAY NIGHT...WITH A SHORTWAVE PUSHING EASTWARD ACROSS THE CWA
LATER TUESDAY AND TUESDAY NIGHT. WILL MENTION SOME SMALL POPS
REGARDING THIS SYSTEM BUT BEST CHANCE LOOKS TO BE SOUTH OF THE CWA.
THE MODELS ONCE AGAIN START TO DIVERGE FROM WEDNESDAY INTO FRIDAY OF
NEXT WEEK...SO THE CONFIDENCE IN ANY PARTICULAR SOLUTION CONTINUES
TO BE LOWER THAN AVERAGE. IN TERMS OF SENSIBLE WEATHER THE IMPACT IS
NOT TOO GREAT...AS IT DOES LOOK LIKE PRECIPITATION CHANCES WILL
EXIST NO MATTER WHICH MODEL...AND TEMPS APPEAR TO CONTINUE ABOVE
NORMAL. THROUGHOUT THE PERIOD WE SHOULD SEE HIGH TEMPERATURES RANGE
FROM THE MID 30S TO THE MID 40S...WITH LOWS IN THE 20S TO 30S.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 533 AM CST SAT DEC 5 2015
VFR CONDITIONS ARE EXPECTED TO MAKE A DRAMATIC TRANSITION AS THE
DAY WEARS ON ACROSS THE TAF SITES. HIGH RESOLUTION MODELS SUCH AS
THE HRRR AND RAP INDICATE THE DEVELOPMENT IN PLACE OF LOW CLOUDS
AND FOG AS THE DAY WEARS ON. THE LOW CLOUDS AND FOG ARE EXPECTED
TO DEVELOP ALONG AND AHEAD OF A COLD FRONT THAT WILL MOVE ACROSS
THE NORTHLAND TODAY AND TONIGHT. THE FRONT WILL BRING SOME SPOTTY
SHOWERS OR DRIZZLE...BUT THE BIG STORY WILL BE THE DEVELOPMENT OF
MVFR AND EVENTUALLY IFR CIGS/VSBYS. THESE CONDITIONS WILL PERSIST
INTO THE NIGHT. STRONG LLWS WILL CONTINUE AT LEAST THROUGH THE
MORNING AND INTO THE AFTERNOON IN SOME SPOTS.
&&
.PRELIMINARY POINT TEMPS/POPS...
DLH 46 32 42 27 / 10 20 0 0
INL 44 27 39 25 / 10 0 0 0
BRD 43 28 41 24 / 10 10 0 0
HYR 47 34 42 22 / 10 20 0 0
ASX 49 35 43 25 / 10 20 0 0
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
LS...SMALL CRAFT ADVISORY UNTIL 10 PM CST THIS EVENING FOR LSZ121-140-
141-146>148.
&&
$$
UPDATE...GRANING
SHORT TERM...LE
LONG TERM...DAP
AVIATION...DAP
AREA FORECAST DISCUSSION...UPDATED
NWS ST LOUIS MO
1115 AM CST SAT DEC 5 2015
.UPDATE:
Issued at 1112 AM CST Sat Dec 5 2015
Dense fog dissipated a little ahead of schedule with mostly sunny
conditions expected the remainder of the afternoon. Forecast highs
look on target with middle 50s areawide.
CVKING
&&
.SHORT TERM: (Through Late This Afternoon)
Issued at 330 AM CST Sat Dec 5 2015
Once again, fog is the primary concern for the short term forecast
this morning. An expansive area of fog is advecting westward toward
the Mississippi River from Illinois and it looks likely to envelop
much of the STL Metro area before sunrise. Have already expanded
the dense fog advisory issued yesterday evening into east central
Missouri. HRRR and NARRE-TL look to have a pretty good handle on
the fog so far this morning...although they might be a little bit
too aggressive with the westward-southwestward expansion.
Regardless, both models keep visibility down through 14-15Z.
Improvement is pretty rapid between 16-18Z, so the timing of the
advisory still looks pretty good. Temperatures today should be
similar to yesterday, though some of the cooler readings over
central Illinois yesterday will likely expand further west-southwest
today due to the greater areal coverage of the fog today.
Carney
.LONG TERM: (Tonight through Friday)
Issued at 330 AM CST Sat Dec 5 2015
An extended period of above average temps continues to look likely
for much of next week as the polar jet, with very few exceptions,
remains to our north. The flow will overall be low amplitude,
facilitating a progressive movement to any systems, and indeed, our
area will be treated to a series of storm systems originating over
the Pacific that will be quick hitting, which will incidentally,
limit their ability to moisten the column sufficiently to allow
pcpn.
The first system is slated for Sunday, and this looks to be the one
where confidence is highest that it will produce pcpn for some
areas. Models have come together nicely on timing now that it is
over land and can be sampled better, ranging from beginning Sunday
morning over northeast and central MO, to exiting southwest IL by
late Sunday evening. There is also good consensus on track, with
the strongest lift associated with the core of the system expected
over northern MO and central IL, and have placed highest PoPs in
these areas as a result--corresponding to our northern CWA. Even
then, moisture will struggle with this system, with its relatively
fast movement, northern track, very dry column already in place, and
no help whatsoever from low level flow. So highest PoPs for this
system look to be just below 50% in the north, trailing to slight
chance 20% in southern MO and IL. Pcpn-types should be all rain
with warm air aloft and above freezing surface temps.
Additional fast moving Pacific systems will slide thru, Monday
night, Tuesday night, and again Thursday-Friday, but with marginal
conditions at best and specific tracks enough in doubt (large enough
model spreads) whereby they will need all the lift they can muster
to generate pcpn, leaned dry on the forecast for much of next week
for now, with PoPs possibly needed down the road as track confidence
increases.
Otherwise, very mild week on tap after Sunday, with what should be
daytime maxes at least in the 50s, possibly 60s, and nighttime mins
above freezing.
A pattern change looks set to occur for the third week of December,
with large height falls and a longwave TROF setting up over the
central CONUS. This should open the way for cold air intrusions
heading towards Christmas that we have not really seen thus far this
late autumn and early winter.
TES
&&
.AVIATION: (For the 18z TAFs through 18z Sunday Afternoon)
Issued at 1112 AM CST Sat Dec 5 2015
Dense fog has dissipated. VFR conditions expected the rest of the
day. Could see some valley fog develop again Sunday morning, but
mid deck of clouds should also be spreading east with the approach
of an upper level storm system. Not much moisture expected with
this system so have kept forecast dry at this time. Light
southeast wind to become southwest on Sunday.
Specifics for KSTL:
VFR conditions expected with a steady increase of high clouds
tonight and mid level clouds on Sunday. Can`t rule out some light
rain on Sunday, but confidence too low at this time to include in
the forecast. Light southeast wind will become southwest.
CVKING
&&
.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
1125 AM CST SAT DEC 5 2015
.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 335 AM CST SAT DEC 5 2015
PCPN CHANCES TONIGHT AND TEMPS THE NEXT FEW DAYS ARE THE MAIN FCST
CONCERNS.
TROUGH OVER THE ROCKIES REMAINS PROGRESSIVE WITH 12 HOUR HEIGHT
FALLS AT 00Z AS HIGH AS 110 METERS AT KGGW. WEAKER HEIGHT FALLS
EXTENDED BACK TO THE S AND SW INTO SRN CA AND AZ. WATER VAPOR LOOP
IN COMBINATION WITH RECENT RUC MODEL INITIALIZATIONS SHOWED THE
TROUGH AXIS FROM NEAR THE ID/WY BORDER SWD INTO AZ. SFC ANLYS AT
09Z DEPICTED CDFNT FROM ERN ND INTO WRN NE.
EXPECT INCREASING/THICKENING CLOUD COVER FOR THE AREA TODAY AS THE
TROUGH OVER THE ROCKIES MOVES EWD. RAIN CHANCES SHOULD HOLD OFF
UNTIL AFTER 6 PM...THEN INCREASE AS LIFT CAUSES MID LEVEL
SATURATION. HIGH RESOLUTION GFS SEEMS TO HAVE A DECENT HANDLE ON
TIMING. PCPN AMOUNTS OVERNIGHT SHOULD BE FAIRLY LIGHT...AND FCST
SOUNDINGS SUGGEST PCPN TYPE REMAINING LIQUID. LINGERED A SLIGHT
CHANCE OF LIGHT RAIN IN SWRN IA AND THE SERN TIP OF NE. WEAK
RIDGING ALOFT MOVES IN LATER SUN...AND CLOUDS WILL DECREASE.
GENLY USED A BLEND OF AVAILABLE MOS GUIDANCE...WITH HIGHEST WEIGHT
GIVEN TO 00Z GFS.
.LONG TERM...(MONDAY NIGHT THROUGH FRIDAY)
ISSUED AT 335 AM CST SAT DEC 5 2015
KEPT THIS PERIOD MAINLY DRY. A FAST MOVING SHORTWAVE TROUGH WILL
MOVE INTO THE CNTRL PLAINS TUE...BUT MOISTURE LOOKS LIMITED FOR
OUR AREA. CHANCES ARE BEST FROM THE DKTS INTO MN AND NRN IA...BUT
WILL NEED TO WATCH THIS IN FUTURE MODEL RUNS. ANOTHER SHORTWAVE
TROUGH MOVES ACRS THE AREA THU...BUT AGAIN MOISTURE LOOKS LIMITED
FOR ERN NE AND SWRN IA. TEMPS SHOULD BE FAIRLY MILD THROUGH THE
PERIOD...WITH THU PROBABLY THE WARMEST DAY FOR KLNK AND KOMA.
&&
.AVIATION...(18Z TAFS FOR KOFK...KLNK AND KOMA.)
ISSUED AT 1117 AM CST SAT DEC 5 2015
DESPITE THE FAIRLY STRONG SHORTWAVE AND FRONT MOVING THROUGH THE
REGION...THE TAF SITES SHOULD EXPERIECE MOSTLY VFR CONDITIONS
THROUGH THIS PERIOD. AN IFR CLOUD DECK WAS NOTED AT 17Z FROM
CENTRAL INTO NORTHEAST NEBRAKSA WITH CIGS008-014...BUT THIS SHOULD
MOVE NORTHEAST OUT OF THE REGION BY THIS EVENING. OTHERWISE KOMA-
KLNK MAY SEE A FEW HOURS OF OVC040 THIS EVENING WHILE THE FRONT
IS MOVING THROUGH. LIGHT SHOWERS MIGHT BE WIDELY SCATTERED THIS
EVENING BUT SHOULD HAVE LITTLE IMPACT ON VISIBILITY. OTHERWISE
WINDS SHIFT FROM SOUTH TO NORTHWEST AS THE FRONT PASSES.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
SHORT TERM...MILLER
LONG TERM...MILLER
AVIATION...NIETFELD
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
301 PM CST SAT DEC 5 2015
.SHORT TERM...(THIS EVENING THROUGH SUNDAY NIGHT)
ISSUED AT 300 PM CST SAT DEC 5 2015
THE MAIN CHALLENGE WILL CONTINUE TO BE TEMPS WITH VERY MILD TEMPS
CONTINUING INTO THE MIDDLE OF NEXT WEEK. MODELS ARE IN GOOD
AGREEMENT WITH LARGER SCALE FEATURES...BUT STRUGGLING WITH LOW
LEVEL TEMPS. THE MAV MOS GUIDANCE HAS THE BEST HANDLE ON TEMPS IN
THE NEAR TERM AT LEAST.
FOR TONIGHT...THERE HAS BEEN MELTING OF SNOW IN THE PAST 24
HOURS...AND DEWPOINTS ARE IN THE LOW/MID 30S OVER THE SNOW FIELD
THIS AFTERNOON. EVEN WITH WESTERLY WINDS IN THE 5 TO 10 MPH RANGE
FOR MUCH OF THE NIGHT...THERE SHOULD BE AT LEAST SOME PATCHY FOG
OVER THE SNOW AREAS. MODELS DO NOT INDICATE TOO MUCH
FOG...ALTHOUGH THE LATEST HRRR IS INDICATING SOME LOWER VSBYS OVER
MN SINCE WINDS HERE MAY BE FAIRLY LIGHT. TEMPS WILL BE WELL ABOVE
NORMAL GENERALLY IN THE LOW/MID 20S.
FOR SUNDAY...TEMPERATURES WILL BE VERY SIMILAR TO TODAY AND
PERHAPS A FEW DEGREES WARMER WITH 925MB TEMPS NEAR +10C BY
AFTERNOON. WE WILL CONTINUE TO GO THE WARMEST OVER THE SNOW FREE
AREAS IN NORTHEAST ND.
ON SUNDAY NIGHT...ANOTHER MILD NIGHT WITH SOUTHERLY WINDS AROUND
10 MPH THAT SHOULD PRECLUDE ANY FOG FORMATION.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 300 PM CST SAT DEC 5 2015
ON MONDAY...925MB TEMPS COOL SOME BUT ARE STILL WELL ABOVE 0C.
THERE SHOULD BE WESTERLY SFC WINDS THAT WILL ONCE AGAIN BOOST
TEMPS TO AROUND 40 PERHAPS EVEN MID 40S FOR SOME WITH MINIMAL SNOW
COVER.
FOR MONDAY NIGHT...EXPECT INCREASING CLOUDS AND WINDS REMAINING
A BIT ELEVATED. THIS SHOULD MEAN A VERY MILD NIGHT WITH OVERNIGHT
LOWS AROUND 30.
FOR TUE...A SHORTWAVE WILL SWING THROUGH THE REGION AND BRING A
LOW CHANCE FOR SOME LIGHT RAIN. THERE COULD BE A BRIEF WINDOW
EARLY TUE MORNING FOR SOME FREEZING RAIN...BUT WITH TEMPS SO MILD
NOT EXPECTING THIS TO BE ANY TYPE OF THREAT SO WILL KEEP IT ALL
LIQUID RAIN FOR NOW. TEMPS SHOULD ONCE AGAIN WARM TO AROUND 40 OR
THE MID 40S FOR ALL AREAS WITH MORE CLOUDS IN THE EAST.
FORECAST STARTING ON WEDNESDAY NIGHT LOOKS A BIT ON THE ACTIVE
SIDE...POTENTIALLY. THE 12Z GFS AND ECMWF BOTH HAVE AN UPPER LOW
BARRELING ALONG THE CANADIAN BORDER EASTWARD ON WEDNESDAY NIGHT. LOW
LEVEL TEMPS ARE ABOVE FREEZING AHEAD OF THIS SYSTEM...THEN DROPPING
BELOW FREEZING. WHICH MEANS RAIN CHANGING TO SNOW POSSIBLY. THE BEST
CHANCE FOR PRECIPITATION WITH THIS SYSTEM WILL BE OVER NORTHWESTERN
MN...WHERE THE ECMWF HAS SIGNIFICANT SNOWFALL FORECASTED. MODELS ARE
TRENDING A LITTLE FURTHER SOUTH AND WETTER WITH THE WED NIGHT/THU
SYSTEM. A SHOT OF COOLER AIR IS THEN COMING FOR THE WEEKEND. THE GFS
HAS A POTENT LOW MOVING NE ACROSS THE REGION FOR SATURDAY...WHILE
THE ECMWF KEEPS IT A BIT FURTHER EAST AND A LITTLE WEAKER. THE ECMWF
HAS TRENDED WESTWARD A BIT WITH THIS ONE...BACK FURTHER WEST INTO
THE RED RIVER VALLEY. SO...A CHANCE FOR PRECIP ON SATURDAY SEEMS
REASONABLE...WITH COOLER TEMPS COMPARED TO THE PREVIOUS WEEK`S
WARMTH.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1210 PM CST SAT DEC 5 2015
EXPECTING MAINLY HIGH CLOUDS TODAY. HOWEVER...AN AREA OF STRATUS HAS
EXPANDED SOUTH OF KBJI. HAVE OPTED TO INCLUDE A TEMPO GROUP FOR A
REASONABLE LIKELIHOOD OF MVFR CIGS AT KBJI THIS AFTERNOON. MODEL
SOUNDINGS ARE INDICATING PLENTY OF LOW LEVEL RELATIVE HUMIDITY THE
LOW LEVELS AT KBJI THIS AFTERNOON...AT LEAST. ALSO HAVE A CONCERN
FOR FOG TONIGHT ACROSS ENTIRE AREA. MODELS HAVE SATURATED LOW LEVELS
FOR MOST SITES...BUT VERY SHALLOW. LATEST MET/MAV GUIDANCE AND HRRR
MODEL DON`T INDICATE FOG BEING A CONCERN. HOWEVER...HARD TO SAY IF
THEY ARE PROPERLY CONSIDERING MELTING EFFECTS. BUFKIT INDICATES
MIXING COULD LIMIT DEVELOPMENT. FOG MIGHT BE MORE ON THE PATCHY SIDE
IF IT DEVELOPS...SO KEPT IT OUT OF TAFS FOR NOW. MAIN CONCERN WILL
BE POTENTIAL FOR STRATUS IN KBJI AREA...AND HOW LONG IT MIGHT
LINGER.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
SHORT TERM...DK
LONG TERM...DK/KNUTSVIG
AVIATION...RK
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
539 PM EST SAT DEC 5 2015
.SYNOPSIS...
SURFACE HIGH PRESSURE WILL EXTEND ACROSS THE REGION THROUGH
SUNDAY...WITH DRY CONDITIONS EXPECTED. A WEAK AREA OF LOW PRESSURE
WILL MOVE THROUGH THE AREA SUNDAY NIGHT INTO MONDAY...PROVIDING A
CHANCE OF RAIN SHOWERS. GRADUALLY WARMING CONDITIONS ARE EXPECTED
THROUGH THE END OF THE WEEK.
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
ALTHOUGH MOST OF THE FORECAST AREA CLEARED OUT OF THE STRATUS/FOG
BY MID-AFTERNOON...A FEW PATCHES REMAINED IN PLACE. ONE PATCH HAS
BEEN CENTERED OVER FAYETTE AND GREENE COUNTIES. ANOTHER IS LOCATED
OVER THE NWS CLE FORECAST AREA...BUT HAS BEGUN MOVING INTO HARDIN
AND UNION COUNTIES. AS THE SUN BEGAN TO SET...VISIBILITIES IN
THESE AREAS QUICKLY DROPPED TO NEAR-ZERO...AND THERE IS EVERY
REASON TO BELIEVE THAT BOTH AREAS WILL CONTINUE TO EXPAND.
THUS...A DENSE FOG ADVISORY HAS BEEN ISSUED...COVERING 15 COUNTIES
(AND LIKELY TO EXPAND LATER THIS EVENING).
THE REST OF THE FORECAST IS UNCHANGED.
PREVIOUS DISCUSSION >
A SIGNIFICANT DENSE FOG EVENT...WITH SOME RIME ICING...OCCURRED
ACROSS THE AREA THIS MORNING. AS INDICATED IN A SOCIAL MEDIA POST
FROM OUR OFFICE EARLIER TODAY...THE LOW- LEVEL INVERSION WAS
EXCEPTIONALLY STRONG...WARMING FROM ABOUT 25F AT THE SURFACE TO
50F AT 2KFT. THIS INVERSION IS MUCH TOO STRONG TO BE TRULY
BROKEN...BUT THERE HAS BEEN JUST ENOUGH MODIFICATION TO THE AIR
MASS TO ALLOW FOR THE STRATUS TO STEADILY DISSIPATE OVER THE PAST
FEW HOURS.
OVERALL...BOUNDARY LAYER MOISTURE HAS CHANGED VERY LITTLE...AND
SURFACE DEWPOINTS HAVE ACTUALLY INCREASED TODAY. THIS CONTRASTS
REMARKABLY WITH RAW GFS / GFS MOS PROJECTIONS...WHICH INITIALIZED
AT 12Z WITH SURFACE DEWPOINT ERRORS OF AS MUCH AS 20
DEGREES...ERRORS WHICH RENDER THE MODEL MOSTLY USELESS FOR THIS
FORECAST CYCLE. OTHER MODELS WERE ALSO A LITTLE TOO LOW ON
DEWPOINTS...BUT RAW NAM NUMBERS (FOR BOTH T/TD) WERE ALIGNING VERY
CLOSE TO CURRENT OBSERVATIONS.
USING THESE NUMBERS AS GUIDANCE...AS WELL AS CONTINUED PATTERN
RECOGNITION...THERE IS GOOD REASON TO FORECAST ANOTHER NIGHT OF
FOG FOR THE ILN FORECAST AREA. WORKING AGAINST THE THREAT WILL BE
THAT THE CENTER OF THE HIGH WILL NOT BE DIRECTLY OVER THE REGION
(ALLOWING SOME LIGHT WIND FLOW)...AND THE VERY-SLIGHTLY-MODIFIED
AIR MASS MEANS THAT FOG MAY BE A LITTLE MORE SHALLOW THAN LAST
NIGHT. NONETHELESS...THE STABLE AIR MASS AND STRONG INVERSION WILL
CONTINUE TO SUPPORT A NEAR-SURFACE STABLE LAYER...AND STRATUS/FOG
DEVELOPMENT IS EXPECTED TO BEGIN QUICKLY AFTER SUNSET. FOG HAS
BEEN INCLUDED WITH EMPHASIS IN THE GRIDDED FORECAST AND THE
HAZARDOUS WEATHER OUTLOOK. THE ONLY REAL UNCERTAINTY IS IN THE FAR
SOUTHERN SECTIONS OF THE CWA...WHERE CONDITIONS CLEARED OUT MORE
QUICKLY THIS MORNING...AND HRRR VISIBILITY PROJECTIONS SUGGEST THE
DENSE FOG MAY STOP SHORT OF REACHING.
WITH LITTLE CHANGE TO THE AIR MASS...MIN TEMPS WERE KEPT VERY
CLOSE TO VALUES FROM LAST NIGHT. HOWEVER...WITH THE TIMING AND
PLACEMENT OF THE EVENTUAL PATCHES OF FOG/STRATUS TO DEVELOP
(EVENTUALLY BECOMING AT LEAST SOMEWHAT WIDESPREAD)...THE EXACT
MIN TEMPERATURE FORECAST FOR ANY GIVEN LOCATION HAS A SLIGHTLY
LOWER CONFIDENCE THAN USUAL.
&&
.SHORT TERM /6 AM SUNDAY MORNING THROUGH MONDAY NIGHT/...
FOG WILL LIKELY BE IN PLACE FOR MOST OF THE AREA TO START SUNDAY
MORNING. WITH A SWITCH TO SOUTHERLY NEAR-SURFACE FLOW...AND A
VERY SLIGHTLY WARMER/DRIER AIR MASS OVERALL COMPARED TO THIS
MORNING...THE EXPECTATION IS THAT FOG/STRATUS WILL DISSIPATE A
LITTLE QUICKER THAN OCCURRED TODAY. THE MAX TEMPERATURE FORECAST
WAS STILL KEPT SOMEWHAT CONSERVATIVE DUE TO THE POTENTIAL FOR
CLOUDS...BUT THE ENTIRE CWA WILL LIKELY MAKE IT INTO THE MIDDLE TO
UPPER 40S ONCE THINGS CLEAR OUT...WITH LOWER 50S IN THE FAR
SOUTHEAST (WHERE SUNNY CONDITIONS ARE EXPECTED EVEN SOONER).
ON SUNDAY NIGHT...A WELL-DEFINED UPPER LOW WILL MOVE EAST THROUGH
THE SOUTHERN GREAT LAKES / NORTHERN OHIO VALLEY. THIS LOW IS NOT
PARTICULARLY STRONG...AND ASIDE FROM AN UNIMPRESSIVE SURFACE WIND
SHIFT...LOW-LEVEL FORCING IS EXPECTED TO BE VERY WEAK AS WELL.
THE COOLING AIR ALOFT WILL FINALLY HELP TO ERODE SOME OF THE
STRONG INVERSION...BUT MOISTURE WILL REMAIN FAIRLY SHALLOW...AND
WIDESPREAD PRECIPITATION IS NOT EXPECTED TO DEVELOP. THE CURRENT
RANGE OF POP VALUES (10-40 PERCENT FROM NORTH TO SOUTH) STILL
MATCHES FORECAST EXPECTATIONS NICELY...WITH TIMING REFINED BASED
ON 12Z RUNS...AND THE AREA SLIGHTLY EXPANDED. BECAUSE OF THE
INVERSION...THIS PRECIPITATION WILL LIKELY BE ALL RAIN...EVEN
THOUGH SURFACE TEMPERATURES EARLY MONDAY MORNING WILL BE IN THE
MID 30S.
SOME WEAK COLD ADVECTION BEHIND THE UPPER LOW WILL KEEP
TEMPERATURES IN THE MID 40S ON MONDAY...NEAR OR JUST ABOVE
NORMAL.
&&
.LONG TERM /TUESDAY THROUGH SATURDAY/...
A COUPLE OF PROGRESSIVE S/WVS ARE FORECAST TO TRAVERSE FROM WEST TO
EAST ACROSS THE GREAT LAKES AND OHIO VALLEY REGION DURING THE EARLY
TO MID WEEK PERIOD. TUESDAY/S DISTURBANCE IS EXPECTED TO BE WEAK AND
MOISTURE STARVED...SO ONLY CLOUDS ARE FORECAST. THE SECOND
DISTURBANCE FOR WEDNESDAY/WEDNESDAY NIGHT IS A LITTLE STRONGER AND
HAS DEEPER MOISTURE IN ASSOCIATION WITH A COLD FRONT. HAVE CONTINUE
WITH A CHANCE OF SHOWERS DURING THIS TIME FRAME.
THE FORECAST BECOMES LESS CLEAR AS WE HEAD INTO THE END OF THE
WEEK...ESPECIALLY IN REGARDS TO AREAL COVERAGE AND PROBABILITY OF
PCPN. THE FLOW DOES BECOME MORE AMPLIFIED WITH A LARGE SCALE MID
LEVEL TROUGH DIGGING OUT ACROSS THE WESTERN U.S. AND RIDGING
DEVELOPING OVER THE EASTERN U.S. S/WV ENERGY FOR THURSDAY/FRIDAY
VARIOUS AMONGST THE MODELS IN TERMS OF HOW STRONG/DEEP IT WILL BE AS
IT PASSES THROUGH THE GREAT LAKES. HAVE KEPT POPS ON THE LOW SIDE
DUE TO HIGH UNCERTAINTY. FOR SATURDAY...LOOKS LIKE MID LEVEL RIDGING
AND A WARM FRONT WILL LIFT THROUGH OUR REGION. WARMER TEMPERATURES
AND SOME WAA SHOWERS WILL BE POSSIBLE.
IT WILL CONTINUE TO BE WARMER THAN NORMAL THROUGH THE PERIOD WITH
TEMPERATURES WARMING INTO THE UPPER 50S TO THE LOWER 60S BY THE
WEEKEND...WHICH IS SOME 20 DEGREES ABOVE NORMAL FOR MID DECEMBER.
&&
.AVIATION /00Z SUNDAY THROUGH THURSDAY/...
LIFR CONDITIONS IN FOG AND FREEZING FOG WILL RAPIDLY BECOME VFR
THIS AFTERNOON WITH NO CIG AND PATCHY MVFR VSBYS THROUGH ABOUT
20Z. EXPECT THE FOG TO MAKE ANOTHER APPEARANCE TONIGHT AS THE
TEMPERATURE INVERSION PERMITS MOISTURE TO BE TRAPPED IN AN EVEN
SHALLOWER LAYER TONIGHT. WHILE LAYER MAY BE MUCH MORE
SHALLOW...THIS WILL JUST MEAN THAT THE FOG THAT DEVELOPS TONIGHT
WILL BE QUICKER TO DISSIPATE TOMORROW. IT SHOULD BE JUST AS DENSE
GIVEN THAT THE WIND FIELDS WILL NOT BE SUBSTANTIAL TO SCOUR OUT
ANY LOW LEVEL MOISTURE.
OUTLOOK...MVFR CEILINGS POSSIBLE SUNDAY NIGHT INTO MONDAY.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...DENSE FOG ADVISORY UNTIL 10 AM EST SUNDAY FOR OHZ026-044-045-
051>054-061>064-071>073-080.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...HATZOS
NEAR TERM...HATZOS
SHORT TERM...HATZOS
LONG TERM...HICKMAN
AVIATION...FRANKS/NOVAK
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
348 PM EST SAT DEC 5 2015
.SYNOPSIS...
SURFACE HIGH PRESSURE WILL EXTEND ACROSS THE REGION THROUGH
SUNDAY...WITH DRY CONDITIONS EXPECTED. A WEAK AREA OF LOW PRESSURE
WILL MOVE THROUGH THE AREA SUNDAY NIGHT INTO MONDAY...PROVIDING A
CHANCE OF RAIN SHOWERS. GRADUALLY WARMING CONDITIONS ARE EXPECTED
THROUGH THE END OF THE WEEK.
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
A SIGNIFICANT DENSE FOG EVENT...WITH SOME RIME ICING...OCCURRED
ACROSS THE AREA THIS MORNING. AS INDICATED IN A SOCIAL MEDIA POST
FROM OUR OFFICE EARLIER TODAY...THE LOW-LEVEL INVERSION WAS
EXCEPTIONALLY STRONG...WARMING FROM ABOUT 25F AT THE SURFACE TO
50F AT 2KFT. THIS INVERSION IS MUCH TOO STRONG TO BE TRULY
BROKEN...BUT THERE HAS BEEN JUST ENOUGH MODIFICATION TO THE AIR
MASS TO ALLOW FOR THE STRATUS TO STEADILY DISSIPATE OVER THE PAST
FEW HOURS.
OVERALL...BOUNDARY LAYER MOISTURE HAS CHANGED VERY LITTLE...AND
SURFACE DEWPOINTS HAVE ACTUALLY INCREASED TODAY. THIS CONTRASTS
REMARKABLY WITH RAW GFS / GFS MOS PROJECTIONS...WHICH INITIALIZED
AT 12Z WITH SURFACE DEWPOINT ERRORS OF AS MUCH AS 20
DEGREES...ERRORS WHICH RENDER THE MODEL MOSTLY USELESS FOR THIS
FORECAST CYCLE. OTHER MODELS WERE ALSO A LITTLE TOO LOW ON
DEWPOINTS...BUT RAW NAM NUMBERS (FOR BOTH T/TD) WERE ALIGNING VERY
CLOSE TO CURRENT OBSERVATIONS.
USING THESE NUMBERS AS GUIDANCE...AS WELL AS CONTINUED PATTERN
RECOGNITION...THERE IS GOOD REASON TO FORECAST ANOTHER NIGHT OF
FOG FOR THE ILN FORECAST AREA. WORKING AGAINST THE THREAT WILL BE
THAT THE CENTER OF THE HIGH WILL NOT BE DIRECTLY OVER THE REGION
(ALLOWING SOME LIGHT WIND FLOW)...AND THE VERY-SLIGHTLY-MODIFIED
AIR MASS MEANS THAT FOG MAY BE A LITTLE MORE SHALLOW THAN LAST
NIGHT. NONETHELESS...THE STABLE AIR MASS AND STRONG INVERSION WILL
CONTINUE TO SUPPORT A NEAR-SURFACE STABLE LAYER...AND STRATUS/FOG
DEVELOPMENT IS EXPECTED TO BEGIN QUICKLY AFTER SUNSET. FOG HAS
BEEN INCLUDED WITH EMPHASIS IN THE GRIDDED FORECAST AND THE
HAZARDOUS WEATHER OUTLOOK. THE ONLY REAL UNCERTAINTY IS IN THE FAR
SOUTHERN SECTIONS OF THE CWA...WHERE CONDITIONS CLEARED OUT MORE
QUICKLY THIS MORNING...AND HRRR VISIBILITY PROJECTIONS SUGGEST THE
DENSE FOG MAY STOP SHORT OF REACHING.
WITH LITTLE CHANGE TO THE AIR MASS...MIN TEMPS WERE KEPT VERY
CLOSE TO VALUES FROM LAST NIGHT. HOWEVER...WITH THE TIMING AND
PLACEMENT OF THE EVENTUAL PATCHES OF FOG/STRATUS TO DEVELOP
(EVENTUALLY BECOMING AT LEAST SOMEWHAT WIDESPREAD)...THE EXACT
MIN TEMPERATURE FORECAST FOR ANY GIVEN LOCATION HAS A SLIGHTLY
LOWER CONFIDENCE THAN USUAL.
&&
.SHORT TERM /6 AM SUNDAY MORNING THROUGH MONDAY NIGHT/...
FOG WILL LIKELY BE IN PLACE FOR MOST OF THE AREA TO START SUNDAY
MORNING. WITH A SWITCH TO SOUTHERLY NEAR-SURFACE FLOW...AND A
VERY SLIGHTLY WARMER/DRIER AIR MASS OVERALL COMPARED TO THIS
MORNING...THE EXPECTATION IS THAT FOG/STRATUS WILL DISSIPATE A
LITTLE QUICKER THAN OCCURRED TODAY. THE MAX TEMPERATURE FORECAST
WAS STILL KEPT SOMEWHAT CONSERVATIVE DUE TO THE POTENTIAL FOR
CLOUDS...BUT THE ENTIRE CWA WILL LIKELY MAKE IT INTO THE MIDDLE TO
UPPER 40S ONCE THINGS CLEAR OUT...WITH LOWER 50S IN THE FAR
SOUTHEAST (WHERE SUNNY CONDITIONS ARE EXPECTED EVEN SOONER).
ON SUNDAY NIGHT...A WELL-DEFINED UPPER LOW WILL MOVE EAST THROUGH
THE SOUTHERN GREAT LAKES / NORTHERN OHIO VALLEY. THIS LOW IS NOT
PARTICULARLY STRONG...AND ASIDE FROM AN UNIMPRESSIVE SURFACE WIND
SHIFT...LOW-LEVEL FORCING IS EXPECTED TO BE VERY WEAK AS WELL.
THE COOLING AIR ALOFT WILL FINALLY HELP TO ERODE SOME OF THE
STRONG INVERSION...BUT MOISTURE WILL REMAIN FAIRLY SHALLOW...AND
WIDESPREAD PRECIPITATION IS NOT EXPECTED TO DEVELOP. THE CURRENT
RANGE OF POP VALUES (10-40 PERCENT FROM NORTH TO SOUTH) STILL
MATCHES FORECAST EXPECTATIONS NICELY...WITH TIMING REFINED BASED
ON 12Z RUNS...AND THE AREA SLIGHTLY EXPANDED. BECAUSE OF THE
INVERSION...THIS PRECIPITATION WILL LIKELY BE ALL RAIN...EVEN
THOUGH SURFACE TEMPERATURES EARLY MONDAY MORNING WILL BE IN THE
MID 30S.
SOME WEAK COLD ADVECTION BEHIND THE UPPER LOW WILL KEEP
TEMPERATURES IN THE MID 40S ON MONDAY...NEAR OR JUST ABOVE
NORMAL.
&&
.LONG TERM /TUESDAY THROUGH SATURDAY/...
A COUPLE OF PROGRESSIVE S/WVS ARE FORECAST TO TRAVERSE FROM WEST TO
EAST ACROSS THE GREAT LAKES AND OHIO VALLEY REGION DURING THE EARLY
TO MID WEEK PERIOD. TUESDAY/S DISTURBANCE IS EXPECTED TO BE WEAK AND
MOISTURE STARVED...SO ONLY CLOUDS ARE FORECAST. THE SECOND
DISTURBANCE FOR WEDNESDAY/WEDNESDAY NIGHT IS A LITTLE STRONGER AND
HAS DEEPER MOISTURE IN ASSOCIATION WITH A COLD FRONT. HAVE CONTINUE
WITH A CHANCE OF SHOWERS DURING THIS TIME FRAME.
THE FORECAST BECOMES LESS CLEAR AS WE HEAD INTO THE END OF THE
WEEK...ESPECIALLY IN REGARDS TO AREAL COVERAGE AND PROBABILITY OF
PCPN. THE FLOW DOES BECOME MORE AMPLIFIED WITH A LARGE SCALE MID
LEVEL TROUGH DIGGING OUT ACROSS THE WESTERN U.S. AND RIDGING
DEVELOPING OVER THE EASTERN U.S. S/WV ENERGY FOR THURSDAY/FRIDAY
VARIOUS AMONGST THE MODELS IN TERMS OF HOW STRONG/DEEP IT WILL BE AS
IT PASSES THROUGH THE GREAT LAKES. HAVE KEPT POPS ON THE LOW SIDE
DUE TO HIGH UNCERTAINTY. FOR SATURDAY...LOOKS LIKE MID LEVEL RIDGING
AND A WARM FRONT WILL LIFT THROUGH OUR REGION. WARMER TEMPERATURES
AND SOME WAA SHOWERS WILL BE POSSIBLE.
IT WILL CONTINUE TO BE WARMER THAN NORMAL THROUGH THE PERIOD WITH
TEMPERATURES WARMING INTO THE UPPER 50S TO THE LOWER 60S BY THE
WEEKEND...WHICH IS SOME 20 DEGREES ABOVE NORMAL FOR MID DECEMBER.
&&
.AVIATION /20Z SATURDAY THROUGH THURSDAY/...
LIFR CONDITIONS IN FOG AND FREEZING FOG WILL RAPIDLY BECOME VFR
THIS AFTERNOON WITH NO CIG AND PATCHY MVFR VSBYS THROUGH ABOUT
20Z. EXPECT THE FOG TO MAKE ANOTHER APPEARANCE TONIGHT AS THE
TEMPERATURE INVERSION PERMITS MOISTURE TO BE TRAPPED IN AN EVEN
SHALLOWER LAYER TONIGHT. WHILE LAYER MAY BE MUCH MORE
SHALLOW...THIS WILL JUST MEAN THAT THE FOG THAT DEVELOPS TONIGHT
WILL BE QUICKER TO DISSIPATE TOMORROW. IT SHOULD BE JUST AS DENSE
GIVEN THAT THE WIND FIELDS WILL NOT BE SUBSTANTIAL TO SCOUR OUT
ANY LOW LEVEL MOISTURE.
OUTLOOK...MVFR CEILINGS POSSIBLE SUNDAY NIGHT INTO MONDAY.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...HATZOS
NEAR TERM...HATZOS
SHORT TERM...HATZOS
LONG TERM...HICKMAN
AVIATION...FRANKS/NOVAK