Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 08/20/17
Area Forecast Discussion
National Weather Service Albany NY
1038 PM EDT Sat Aug 19 2017
.SYNOPSIS...
An upper level trough will bing a threat of isolated showers and
thunderstorms early tonight. High pressure building into the mid-
Atlantic region will bring fair weather and seasonable temperatures
on Sunday. A southwesterly return flow around the high will bring
mostly sunny and warm weather Monday into Tuesday.
&&
.NEAR TERM /THROUGH SUNDAY/...
As of 1030 pm, scattered showers occurring from the Capital
District to the Catskills as well as the Mohawk Valley
downstream of the potent upper wave seen on water vapor imagery.
Lightning has really trended downward in the activity entering
Ulster County, which was the only lightning in the area, so have
removed mention of thunder for the remainder of the night save
for a slight chance mention in the Catskills and Hudson Valley
south of Albany. Otherwise, looking at scattered showers
continuing through around 06Z as the wave pivots through.
BKN/OVC cloud cover spreading across the area, but clearing
seen back toward CNY/NEPA. Could see some fog or low stratus
redevelop once this clearing works overhead post 06Z, so have
left that mention in the forecast.
Previous discussion...As of 426 PM EDT...radar shows a small
shower over western Montgomery County. Stronger showers are over
the Finger lakes and western New York. At this time, only
lightning strikes are with a couple of cells in far western New
york. The heavier showers and storms appear to be a couple of
hours away from our western zones.
Water vapor loop shows the upper level trough axis about between
Toledo and Cleveland, Ohio, in line with the back edge of the
storms. Models indicate this trough should be east of the Albany
Forecast area by 08Z tonight ending the threat for showers.
HRRR seems to agree that there is a threat for showers and
thunderstorms in our area through about 06z for areas west of
the Hudson river and through about 08Z for areas east of the
hudson River.
Expecting showers with isolated general thunderstorms with a
locally heavy downpour possible in a few spots.
&&
.SHORT TERM /SUNDAY NIGHT THROUGH MONDAY NIGHT/...
Any lingering isolated showers and thunderstorms will end around
midnight to 2 AM and the sky will gradually clear. There could
be some patchy fog around daybreak Sunday. Sunday looks dry and
sunny as high pressure builds from the Ohio Valley to the mid-
Atlantic with highs in the 80s and 70s in higher terrain. Sunday
night should be mainly clear and cool under high pressure that
ridges down the eastern sea board. Lows in the 50s and 60s.
Some warm advection begins Monday as southwesterly winds
increase around high pressure near the mid Atlantic coast. Model RH
fields show generally sunny conditions for the local areas so
there should be good viewing of the eclipse. It will start to
feel hot with highs in the 80s many areas and around 80 higher
terrain. It will be interesting to see just how the eclipse does
affect the atmosphere over the entire U.S. with varying
percentages of the sun on either side of the path of the total
eclipse.
A mostly clear sky is expected Monday night with slowly
increasing warm advection and low level moisture. Lows mainly in
the 60s.
&&
.LONG TERM /TUESDAY THROUGH SATURDAY/...
Long term period will feature a transition from summer-like warmth
and humidity to fall-like cooler temperatures and lower humidity.
This transition will occur as upper ridging Tuesday gives way to
lowering heights later Tuesday into the end of the week as an upper
trough sets up over the northeastern portion of North America. As
the lead portion of the upper trough swings in from the Great Lakes
Tuesday into Tuesday night, seasonably strong cyclogenesis is
forecast to occur over southeastern Canada. The resulting low will
drag a cold front through the forecast area, with model consensus
favoring the frontal passage Tuesday night. Convection and severe
weather can typically be expected with transitions such as this one,
but the timing of the frontal passage is not favorable for severe
weather locally. However, there is the possibility of convection
during the diurnal maximum Tuesday afternoon and evening along the
leading edge of the height falls or possibly a pre-frontal trough.
Convective potential is greatest over our northwestern zones (the
Southern Adirondacks) where likely PoPs are in place Tuesday. Chance
PoPs elsewhere. SPC Day 4 15 percent severe risk stops west of our
CWA where frontal timing is more favorable. Showers will be likely
Tuesday night, especially for the northern two-thirds of the
forecast area where forcing looks to be maximized, along with a
chance of thunder. With high temps reaching the 80s to near 90
Tuesday, and dewpoints nearing 70, it will be a hot and humid day,
but the last one through at least next weekend.
Noticeably cooler and drier Wednesday, with possibly a few lingering
showers early especially over western New England depending on
frontal timing. H850 temps fall from the neighborhood of 18C Tuesday
down to around 10C Wednesday, and down toward 8C for the remainder
of the week. The seasonably cool and dry airmass will be in place
for the remainder of the forecast period, characterized by highs in
the mid-60s to mid-70s (although a few degrees warmer than that on
Wednesday) and lows in the mid-40s to mid-50s. A couple of diurnal
showers cannot be ruled out, especially over the terrain with cold
midlevel temps and cyclonic flow, otherwise it should be mostly
dry.
&&
.AVIATION /03Z SUNDAY THROUGH THURSDAY/...
Scattered showers and isolated thunderstorms are advancing into
the region this evening ahead of an upper level wave. Have
adjusted the time of VCSH for each of the terminals based on
observations/short-term model guidance. An isolated thunderstorm
cannot be ruled out during the period denoted by VCSH, but
confidence not high enough for a mention in the TAFs.
Low confidence with whether low stratus/mist will develop
tonight. Area of upstream midlevel clouds may prevent IFR
conditions, and MOS guidance keeps things VFR except for at
KPSF. On the other hand, persistence suggests it`s a good idea
to keep it in for KPSF and KGFL, as the boundary layer remains
somewhat moist. Will keep the previous forecast intact for the
overnight period.
Quick improvement for Sunday after daybreak as high pressure
noses in. VFR expected.
Winds tonight will become light and variable, increasing out of
the west to around 8-12 kt with a few gusts to near 15-20 kt
possible, especially at KALB/KPSF.
Outlook...
Sunday Night: No Operational Impact. Patchy FG.
Monday: No Operational Impact. NO SIG WX.
Monday Night: No Operational Impact. NO SIG WX.
Tuesday: Moderate Operational Impact. Chance of SHRA...TSRA.
Tuesday Night: High Operational Impact. Likely SHRA...TSRA.
Wednesday: Moderate Operational Impact. Chance of SHRA.
Wednesday Night: No Operational Impact. NO SIG WX.
Thursday: No Operational Impact. NO SIG WX.
&&
.FIRE WEATHER...
An upper level trough will bing a threat of isolated showers and
thunderstorms this evening, especially from the Hudson River Valley
westward. High pressure building into the mid-Atlantic region will
bring fair weather and seasonable temperatures on Sunday. A
southwesterly return flow around the high will bring mostly sunny
and hot weather Monday into Tuesday.
RH values will be near 100 percent at night. RH values will be
45 to 65 percent Sunday and Monday afternoon.
West to northwest winds diminish to less than 15 mph tonight.
Winds will be west at 5-15 mph on Sunday with a few gusts to 20
MPH. Winds will switch to southwest and again diminish to 5-10
MPH or less on Sunday night.
&&
.HYDROLOGY...
Widespread rainfall forecast during the next week is forecast to
be less than an inch. Some locally higher amounts are possible
in showers and thunderstorms tonight and again later Tuesday
into Tuesday night. Only minor changes in stage and flow are
forecast for larger rivers and streams.
For details on specific area rivers and lakes, including
observed and forecast river stages and lake elevations, please
visit the Advanced Hydrologic Prediction Service /AHPS/ graphs
on our website.
&&
.EQUIPMENT...
While repairing the azimuthal gear box, radar technicians have
determined that the bull gear on KENX radar needs to be
replaced. This will require the radar to be out of service until
at least next Friday, August 25th.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
MA...None.
VT...None.
&&
$$
SYNOPSIS...SND
NEAR TERM...SND/Thompson
SHORT TERM...SND
LONG TERM...Thompson
AVIATION...Thompson
FIRE WEATHER...SND
HYDROLOGY...SND
EQUIPMENT...
Area Forecast Discussion...UPDATED
National Weather Service Amarillo TX
632 PM CDT Sat Aug 19 2017
.AVIATION...
For the 00Z TAFs, isold to sct showers and tstms over northeast
New Mexico may make some headway into the northwest parts of our
fcst area early this evening before dissipating. Have decided to
leave tstms out of the KGUY and KDHT TAFs due to uncertainty in
how much eastward progress these showers and tstms will make into
our area before falling apart. Will monitor radar trends closely
this evening. Isold showers and tstms may develop again late
Sunday afternoon across parts of the fcst area. However,
confidence is low with respect to where or if this will occur,
which precludes mentioning in the TAFs at this time.
Andrade
&&
.PREV DISCUSSION... /Issued 418 PM CDT Sat Aug 19 2017/
DISCUSSION...
Current upper level analysis reveals high pressure centered over
south Texas helping to shift some monsoonal moisture into the far
western Panhandles. A subtle shortwave rounding the high pressure
has helped initiate a few showers and thunderstorms over the
higher elevations of NM/CO. These may push into the northwestern
zones later this afternoon and evening but should loose steam near
the north-central zones as they encounter some dry air around
600mb-300mb noted on the 12z AMA sounding. This dry air is being
modified some around Guymon and Dalhart due to the monsoonal flow,
so keeping pops through the evening for those areas. Otherwise, a
CU field is noted in the east-central Texas Panhandle due to
diurnal heating. The HRRR has tried to initiated a storm in this
region but it will be difficult given the previously mentioned dry
mid- level air. There is plenty of instability and some low level
theta-E advection, so some very isolated convective initiation is
not out of the question through early evening as temperatures
peak around 90-95 degrees. Some storms could be on the strong
side mainly as a wind threat given steep low level lapse rates
with very marginal 10-20 knots of deep layer shear.
Going Sunday into Monday, the upper level high pressure shifts
eastwards and elongates over the southeastern CONUS while an upper
level cutoff closed low forms and beings spinning off the coast of
southern California. This will lead to more southwesterly flow
over the Panhandles. In addition, a shortwave is progged to move
through the southwest flow late Sunday into Monday. Prior to this,
conditions on Sunday should be mostly dry with mid and upper level
clouds with highs again around average. However, as the upper
shortwave approaches late Sunday, clouds will increase as will
precipitation chances. At this time, models are keeping most of
the influence of this wave across the northwestern half of the
combined Panhandles as an area of showers and thunderstorms
move out of New Mexico and into the western Panhandles late Sunday
into early Monday, and then move east-northeast across the rest of
the area through the day Monday into Monday night. This will lead
to some major challenges for those hoping to see the partial
eclipse across the Panhandles Monday afternoon as most of the area
will see at least mostly cloudy conditions. For now, it looks
like folks in the southeastern Texas Panhandle stand the best
chance of getting to see the eclipse, but if the shortwave tracks
further south that could easily change.
On Tuesday, a "cold" front is expected to move in behind the main
shortwave. This will bring additional chances for showers and
thunderstorms depending on the timing of the front and how much
the atmosphere can recover behind the shortwave. For now the
southern and eastern zones seem to be the most likely to see
precip along the front where mid level moisture is increased.
Temperatures should drop below average behind the front, with most
of the Panhandles in the 80s for highs on Wednesday.
Models suggest the return of northwest flow towards the end of
next week as high pressure builds over the southern Rockies with
a warming trend back to around average. Showers and thunderstorms
should become more nocturnal as they move off the higher terrain
in response to shortwaves moving through the northwest flow. This
will also lead to a better chance for some strong to severe storms
as deep layer directional shear increases in combination with
steep lapse rates and plenty of moisture and buoyancy.
Ward
AVIATION...18Z TAFS...
VFR conditions are expected to prevail over the next 24 hours.
Thunderstorm chances look very dim at this point. If storms should
develop they will likely be west of KGUY and northwest of KDHT
and should stay out of the 10 mile range for VCTS. Thusly, if
things should change will defer to TAF amendments should
conditions become more favorable. Winds will generally be out of
the south 5 to 15 kts.
Weber
&&
.AMA Watches/Warnings/Advisories...
TX...None.
OK...None.
&&
$$
Area Forecast Discussion
National Weather Service Binghamton NY
906 PM EDT Sat Aug 19 2017
.SYNOPSIS...
An upper level disturbance will move across NY and PA this
afternoon and evening bringing scattered showers and isolated
thunderstorms to our area. After this disturbance passes by,
high pressure will build into our region for Sunday and Monday
with fair weather and seasonable temperatures. The next chance
for precipitation will come Tuesday as a cold front approaches
the region.
&&
.NEAR TERM /THROUGH SUNDAY/...
900 pm update...
Thunderstorms continue to weaken across ne PA and the Catskills
of NY with trailing rain showers over areas of central NY. This
trend will continue through the next 1-3 hours before all the
convection subsides. Rest of the forecast remains on track with
a very pleasant day expected tomorrow and Monday.
Previous Discussion...
Scattered showers are developing across western NY and
northwest Pennsylvania as weak capping indicated on the 12z
Buffalo sounding begins to break down. Strongest storms are
beginning to develop over eastern Ohio and these will track
east-southeast across western Pa during the next few hours
remaining well to our south and west. Latest HRRR and RAP
forecasts continue to indicate only marginal levels of
instability in our area with MLCAPE values maxing out near or
just above 500 J/kg and the best chances for organized
convection remaining to our south and west. We are expecting
scattered showers with isolated thunder to move across our area
during the mid afternoon through early evening followed by
clearing overnight, then patchy low clouds and fog around
daybreak Sunday. Sunday looks like a mostly sunny and seasonably
warm day with highs in the mid 70s to lower 80s as high
pressure builds across the area.
&&
.SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY NIGHT/...
300 PM EDT Update...
Minor changes were made to the previous forecast. Zonal flows
will prevail over the region from Sunday night through Tuesday
morning, combined with ridging at mid-lvls and surface high
pressure. This combination will result in mostly sunny skies,
above normal temperatures with no chance for precip.
Temps Monday night will range in the mid 50s/low 60s. Temps Tues
afternoon will rise into the mid/upper 80s and fall into the 60s
Tues night.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
300 PM EDT Update...
Updated with new WPC guidance...
Surface high pressure will slide off to the east early Tuesday
morning as the next storm system approaches the region from the
west. There continues to be fairly decent model agreement on the
timing of the next system with showers moving into western NY
as a sfc low moves NE into Quebec Tuesday night and a fropa
moves across Ny/PA Tues night. Showers and thunderstorms are
likely across the region late Tuesday evening into Tuesday
night. This could be our next shot for a widespread rainfall
event. The upper level shortwave that will force the sfc
low/fropa across the region will be slow to move east, thus
showers and and a possible rumble of thunder will be possible
through Thursday. High pressure is expected to build back into
the area Thurs evening.
&&
.AVIATION /01Z SUNDAY THROUGH THURSDAY/...
Showers and thunderstorms will weaken over the next couple
hours leaving VFR conditions. Valley fog will form once again
bringing a chance for VLIFR to ELM, and spotty MVFR elsewhere.
For Sunday, drier air and VFR conditions are expected through
the day.
Outlook...
Monday...VFR. Possible IFR in valley fog early.
Tuesday...Restrictions possible in thunderstorms.
Wednesday/Thursday...VFR.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...None.
NY...None.
&&
$$
SYNOPSIS...DJN
NEAR TERM...BJT/DJN/MSE
SHORT TERM...KAH
LONG TERM...KAH
AVIATION...DGM/MSE
Area Forecast Discussion
National Weather Service Billings MT
927 PM MDT Sat Aug 19 2017
.UPDATE...
Reduced coverage of thunderstorms. Cumulus as struggled to develop
any further as it drifts through the region. Airmass is pretty dry
and despite shortwave approaching have not observed any impact on
vertical ascent and HRRR guidance has been downward trending all
evening. Update sent. dlb
&&
.SHORT TERM...valid for Sun and Mon...
Weak front pushing south through the area today has brought
northwest to north winds and occasional gusts around 25 mph.
Despite areas of smoke/haze from wildfires across western Montana
and the Pac NW and middle to high level clouds overhead,
temperatures have climbed into the 80s to near 90 degrees in some
places this afternoon. Winds will turn more northeasterly through
the remainder of the afternoon and evening, helping to push some
of the smoke out of the area and improve air quality. Isolated
showers and thunderstorms become possible over the southwest
mountains later this afternoon, potentially moving out onto the
plains into the evening as a weak disturbance moves through the
region and upslope flow develops near the surface. Better chances
for showers and thunderstorms exist this evening and overnight
across southeast Montana.
Zonal flow will persist through Sunday with southeasterly flow
developing at the surface. Moisture and instability will advect
into eastern areas through the day with thunderstorm chances
increasing across the far east late in the day and into the
evening as another disturbance and associated front approaches
from the west. Nocturnal convection looks possible, with some of
the storms being potentially strong during the evening and
overnight as a low level jet develops out ahead of the
aforementioned front. Winds will turn northerly behind the front
Monday morning as a trof remains over the area through the first
part of the day, before ridging begins to build in from the west.
As far as viewing for the Eclipse in southern Montana and
northern Wyoming, models continue to indicate middle to high level
clouds over much of the area through most of the morning,
potentially moving off to the east after midday. A lot of
uncertainty remains in the cloud forecast to say the least.
High temperatures will generally be in the 80s for most of the
lower elevations Sunday and Monday. STP
.LONG TERM...valid for Tue...Wed...Thu...Fri...Sat...
Following Mondays weak cold front, upper ridge builds into the
area for Tuesday through Thursday for quiet weather. By late
Thursday some monsoonal moisture will begin to work into the
southern mountains for an isolated thunderstorm or two in the
afternoon/evening. Upper trof pushes into the Pacific Northwest
and into our area Friday for a better chance of thunderstorms as
an associated cold front/wind shift moves through. Bulk of this
system remains north of the area so continue with low pops at this
time. However there is a bit of a Gulf moisture tap that could
bring a bit better chance of rain to areas east of Billings Friday
night into early Saturday if the pattern holds. Dry northerly
flow builds over the rest of the area for Saturday afternoon.
Temperatures look warmest Tuesday into Wednesday with highs
possibly pushing the lower 90s. With cloud cover increasing and
the late week front temperatures slide down toward more seasonal
levels in the low to mid 80s Thursday into the weekend. Chambers
&&
.AVIATION...
VFR conditions will prevail tonight. An isolated shower or
thunderstorm is possible tonight along and south of a Livingston
to Billings to Ekalaka line, with local MVFR conditions possible.
Smoke Forecast...Winds are expected to shift to the northeast
this evening, dispersing smoke to the south of the area and
improving visibility over time. Until then will continue to see
areas of smoke across the area, occasionally reducing visibility
locally to around 5sm west of Rosebud county, including KBIL,
KLVM, and KSHR taf sites. The poorest visibility will be in and
near area foothills. Slant range visibility could be lower than
5sm at times. Chambers
&&
.PRELIMINARY POINT TEMP/POPS...
Sun Mon Tue Wed Thu Fri Sat
-----------------------------------------------------------
BIL 058/084 059/083 055/088 057/092 059/088 057/082 056/083
10/U 10/B 00/U 00/U 11/B 22/T 20/U
LVM 051/082 049/084 047/089 049/091 054/085 050/080 048/083
10/U 00/U 00/U 00/U 12/T 22/T 20/U
HDN 059/087 056/086 053/091 056/095 058/091 057/085 055/085
10/U 11/B 00/U 00/U 01/B 22/T 20/U
MLS 059/085 059/085 055/088 058/092 060/092 059/086 056/086
11/B 21/B 00/U 00/U 01/U 12/T 11/U
4BQ 058/086 057/085 053/087 055/090 057/090 057/086 054/086
32/T 21/B 00/U 00/U 01/B 12/T 21/U
BHK 056/081 055/082 050/082 054/086 056/086 055/084 054/083
22/T 31/B 00/U 00/U 00/U 12/T 32/T
SHR 055/085 053/083 051/087 051/090 053/087 052/083 050/083
10/U 11/B 10/U 00/U 12/T 22/T 21/U
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...None.
WY...None.
&&
$$
weather.gov/billings
Area Forecast Discussion
National Weather Service Grand Forks ND
959 PM CDT Sat Aug 19 2017
.UPDATE...
Issued at 957 PM CDT Sat Aug 19 2017
Latest guidance on both 00Z global models and hi-res models keep
eastern zones dry in the late overnight period. Will pull pops and
focus on potential across south with activity currently in the
Rapid City area. RAP/HRRR bring some morning showers/storms to
SE ND mainly across Sargent and southern Richland counties. Will
use a blend of SREF and HRRR to add POPs. Not expecting much in
way of QPF as not getting any ground truth with echoes entering s
cntrl ND.
&&
.SHORT TERM...(This evening through Sunday)
Issued at 213 PM CDT Sat Aug 19 2017
Forecast challenges concern frontal passage overnight and fire
weather concerns for tomorrow.
Cold front entering nw ND and will be crossing the forecast area
late evening and overnight. Airmass ahead of the front will be
relatively unstable however favored upper support remains north of
the border and convergence with low level jet also focused in
southern Canada. Will maintain current pops as shear increases
aft 06z however with high resolution model and CAM guidance on
the dry side will not increase pops. Good push of cold advection
behind boundary along with about 35 kts at 925 mb however not much
of an adiabatic layer off the deck so unsure of how much of this
can mix down.
Fire weather concerns tomorrow as much drier low level air works
into the fa behind front with dewpoints in the 40s. With cooler
column temperatures will not be as warm. Also winds aloft relax so
do not anticipate any serious gusts and surface winds at 10kts or
so. Will monitor trends but at this point we should be ok.
.LONG TERM...(Sunday night through Saturday)
Issued at 213 PM CDT Sat Aug 19 2017
The new work week will start out with a 500 mb wave passing through
bringing minor precipitation chances to the area. Not much for
impacts as any areas that do see precipitation shouldn`t see much.
However, there is the potential for plenty of cloud cover with the
increased moisture to inhibit the solar eclipse viewing on Monday.
The remainder of the work week looks to be pleasant and dry for the
most part as surface high pressure and upper ridging build in.
Breezy southerly winds late in the week will pull in increasing
moisture and better precipitation chances as the upper ridging moves
off to the east.
Slightly below temperatures are expected through the week (highs in
the 70s and lows in the low to mid 50s) before warming up a bit
closer to the 80 mark towards the end of the period.
&&
.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
Issued at 636 PM CDT Sat Aug 19 2017
VFR. Main aviation concern will be a wind shift as a sfc trough
moves across the region tonight. Southerly winds will become more
westerly by sunrise Sunday morning. There is a chance for some
convection with the boundary as it approaches TVF/BJI however any
activity should be isolated in nature.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...None.
MN...None.
&&
$$
UPDATE...Speicher
SHORT TERM...Voelker
LONG TERM...Lee
AVIATION...Speicher
Area Forecast Discussion...UPDATED
National Weather Service Gray ME
1130 PM EDT Sat Aug 19 2017
.SYNOPSIS...
High pressure will build south of the region Sunday through
Monday before sliding to the east on Tuesday. A cold front will
move in from the west Tuesday night and will cross the region
on Wednesday. High pressure will build in behind the front
Wednesday night through Friday.
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
1124 PM Update: Going forecast in good shape with only minor
tweaks to temperatures...dewpoints and hourly PoPs necessary
given current obs and slower arrival of decaying upstream
convection now entering western MA. Will maintain thunder
mention for now...but MUCAPES are diminishing and expect that
this activity will continue to weaken as it heads north and
east. Watching fog development...with a few locations having
fallen below one mile last hour /PWM-LEW-RKD/. Gradual dry
advection overnight will compete with cooling and for this
reason don/t expect fog to become widespread and dense...but a
few dense patches are possible. Will consider a SPS if VSBY
trends in this direction.
Update...
Have updated the forecast per current observations and trends.
Plenty of Cu remain over northern areas where the terrain kick
will work with limited instability to produce widely scattered
showers and perhaps a stray thunderstorm overnight. This
precipitation will be associated with the passage of an upper
level trough during the overnight hours.
Have also introduced a chance for showers or thunderstorms,
mainly after midnight tonight over southern New Hampshire and
far southwestern Maine. Latest HRRR depicting convection over
eastern New York State surviving the trip through portions of
New England. Sufficient CAPE values to trigger a brief shower or
storm as the moisture potentially rides through York county
Maine by 09Z.
Elsewhere, some low level moisture from yesterdays heavy rain
will become trapped underneath a developing inversion overnight.
This will lead to patchy fog throughout much of the region.
Have made minor adjustments to temperature trends, dew points
and cloud over over the next few hours.
Prev Disc...
At 18z...a 1007 millibar low was off the downeast
coast with a trailing cold front through the Gulf of Maine. A
1001 millibar low was centered over northern Quebec with a
trailing cold front through the eastern Great Lakes. We`re
seeing gradual clearing today behind the departing disturbance
over the Gulf of Maine. However, heating and the approaching
cold front may trigger a brief shower/isolated thunderstorm
through early tonight mainly across the higher terrain.
Overnight...partly cloudy skies with patchy fog and valley
stratus developing in wake of cold front and shortwave impulse
sweeping offshore.
&&
.SHORT TERM /6 AM SUNDAY MORNING THROUGH SUNDAY NIGHT/...
For Sunday...ridging takes hold although we`ll see a few upslope
clouds across the higher terrain. It`ll be a warm day with highs
ranging from the 70s across the mountains...to lower and mid 80s
elsewhere. Partly cloudy Sunday night with some patchy late
night fog and lows in the 50s to lower 60s.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
Models remain in fairly good agreement today on extended forecast
for next week. High pressure will crest over the region early
Monday before shifting offshore south of New England. Return flow
will bring warmer and more humid air back into the northeast
through the day under mostly sunny skies. Highs on Monday will
generally range through the 80s.
Summer-like weather will continue Monday night and Tuesday.
Looking for partly cloudy skies Monday night with lows in the
lower to mid 60s. Tuesday will start off mostly sunny with high
clouds on the increase in the afternoon as a cold front
approaches from the west. Looking like a hot one with highs in the
80s to lower 90s. May see some convective activity reaching far
northwest zones by late in the day but expect a majority of the
forecast area to see a dry day.
Cold front will push in from the west Tuesday night. Looking for
showers and Thunderstorms overnight some of which could be severe
with heavy rainfall. Moderate to strong shear will combine with
PWAT`s approaching 2 inches to produce possible damaging winds
and heavy rainfall. Although timing of the front not ideal...
strong dynamics associated with this shortwave should sustain
convection well into the evening and overnight. Looking for a very
warm and humid night with lows in the 60s to lower 70s.
Cold front will slow as it moves through the region early Wednesday
but should finally move offshore by Wednesday afternoon. Highs on
Wednesday will range from the mid 70s north to the mid 80s south.
Skies will be mostly clear Wednesday night as high pressure begins
building in from the west. Should see much more comfortable
conditions as cooler and drier air shifts into the region on a
northwest flow.
High pressure will dominate the weather for the rest of the week
and into the weekend. Upper trough settling into the northeast will
result in A mix of sun and clouds during the days with mostly clear
and cool conditions at night. Highs Thursday through Saturday will
range through the 70s with lows overnight in the upper 40s to mid
50s.
&&
.AVIATION /04Z SUNDAY THROUGH THURSDAY/...
Short term /through 12z Monday/...Lingering MVFR over mid coast
Maine will become VFR by early evening. Overnight...areas of
MVFR and lcl IFR will redevelop in stratus and fog. Bcmg VFR
throughout Sunday morning with lcl IFR psb btw 08 - 12z Mon in
valley stratus and fog.
Long Term...
VFR Monday through Tuesday. Areas of MVFR/IFR ceilings/vsby in
showers and thunderstorms Tuesday night. Becoming VFR for
Wednesday through Thursday.
&&
.MARINE...
Short Term /through Sunday Night/...Seas continue to diminish
and the small craft advisory for hazardous seas has been
dropped.
Long Term...
SCA`s may be needed Tuesday into Wednesday.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...None.
NH...None.
MARINE...None.
&&
$$
NEAR TERM UPDATE...Arnott
Area Forecast Discussion
National Weather Service Lake Charles LA
847 PM CDT Sat Aug 19 2017
.UPDATE...
Sctd showers and tstms continue to move south and west acrs lower
Acadiana toward coastal southwest LA and the adjacent coastal
waters. This activity developed in conjunction with a shortwave
crossing southeast LA, and aided by strong aftn heating as high
temps reached the upper 90s late this aftn. Updated evening POPs
to reflect ongoing convection which is expected to persist over
the next hour or two, a trend reflected in recent HRRR guidance.
However, activity will continue to weaken and diminish with the
loss of daytime heating, and convection should be mostly
dissipated by midnight.
24
&&
.PREV DISCUSSION... /issued 415 PM CDT Sat Aug 19 2017/
DISCUSSION...Considerable shower and thunderstorm activity
ongoing this afternoon across southern Mississippi and eastern
Louisiana. Activity associated with shortwave energy advancing
south to southwest about the eastern periphery of west gulf
mid/upper high. Will be maintaining pops into the evening hours
over the eastern portion of the forecast area as this feature
moves through. Overall have seen apparent temperatures generally
max at a 103 to 107 range, but did see a few obs briefly higher.
Similar numbers expected Sunday afternoon.
With moisture plentiful in the lowers levels will see hot and
humid days continue followed by warm and muggy nights. Nothing
particularly out of the ordinary. With capping limited or absent
and sufficient moisture, will see a daily chance for mainly
afternoon showers and thunderstorms. Expecting a gradual ramping
up of rains going into the new work-week as low pressure aloft
currently over the eastern gulf advances westward.
MARINE...Surface high pressure over the northwest Gulf will
maintain a light and somewhat variable flow through the weekend.
Winds will trend east to southeast and remain light moving into
the work-week as high pressure becomes oriented across the
southeastern states and adjacent coastal waters. Shower and
thunderstorm activity will be on the increase as low pressure
aloft over the eastern gulf advances slowly east.
23
&&
.PRELIMINARY POINT TEMPS/POPS...
AEX 76 93 75 93 / 20 30 10 40
LCH 79 93 77 92 / 10 30 10 30
LFT 77 93 76 93 / 30 30 10 40
BPT 78 93 78 92 / 10 30 10 30
&&
.LCH WATCHES/WARNINGS/ADVISORIES...
LA...None.
TX...None.
GM...None.
&&
$$