Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 08/15/18
Area Forecast Discussion
National Weather Service Albany NY
1011 PM EDT Tue Aug 14 2018
.SYNOPSIS...
n upper level low pressure system will slowly move
eastward across the region overnight with mainly isolated showers. A
cold front will cross the region late tomorrow bringing another
chance of showers and thunderstorms mainly across northern areas.
Mainly fair and dry weather is expected most of the day on Thursday
with above normal temperatures, especially from the Hudson River
Valley eastward.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
As of 1010 PM EDT...The Flash Flood Watch for the Lake George
Saratoga Region, Mohawk Valley, Sacandaga Region, Schoharie
Valley, Greater Capital District, Eastern Catskills, Mid Hudson
Valley, and the Taconics has been canceled.
The latest RAP and satellite imagery shows the closed/cutoff
low over eastern NY. Isolated to scattered showers and
thunderstorms have pinwheeled around the edges of the forecast
area. We have been spared the heavy rainfall compared to what
WFO BGM has received, and the Flash Flood Watch has been
canceled. The 01Z RAP SPC Mesoanalysis still indicates MLCAPE
values of 500-1000 J/kg over the forecast area, so we kept
isolated thunder in the forecast until midnight. The instability
should wane and spokes of vorticity around the upper low could
continue showers into the early morning hours. An isolated
threat was continued until 06Z-08Z. PWATS remain high at 1.60"
per the latest 00Z KALY sounding, but should lower overnight.
Clouds will likely become variable with some patchy fog
especially where rainfall has occurred and with the light to
calm winds.
Lows will be mainly in the lower to mid 60s with a few upper 50s
over the mtns.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH FRIDAY/...
For Wednesday more wet weather is possible mainly across northern
areas as a cold front drops southeast from the Saint Lawrence
Valley. PWATS Wednesday afternoon are generally under 1.5 inches
except across northern areas where they are as high as 1.75 inches.
Storms should be moving fairly fast Wednesday afternoon based on the
H7 flow, generally at 30 to 40 kts. MLMUCAPES are generally 1000 to
3000 J/KG across much of the region with 0-6 km bulk shear 25 to 30+
kts. H7-H5 lapse rates are generally 6 to 6.5 C/km. So some stronger
storms are certainly possible Wednesday afternoon especially across
northern areas where SPC has a marginal risk in effect. Highs on
Wednesday will be in the upper 70s to upper 80s.
Wednesday night looks mainly dry as a weak ridge of high pressure
tries to build into the region. Lows will be in the upper 50s to
upper 60s.
On Thursday expect a mostly dry day except cannot rule out a shower
or thunderstorm mainly across western areas during the afternoon as
a warm front will be lifting northeast from the Ohio Valley. Highs
will be in the upper 70s to around 90.
For Thursday night there will be a chance of showers across the
northwest half of the forecast area as the warm front moves into
central New York by Friday morning. Lows will be in the mid 60s to
lower 70s.
Friday looks to be another active day as showers and thunderstorms
will become more numerous during the day with the warm front
lifting northeast through the forecast area as a cold front
approaches from the eastern Great Lakes with low pressure tracking
across southern Canada. PWATS rise to over 2 inches across much of
the region on Friday so have once again introduced the mention of
heavy rain. MLMUCAPES rise to 1500 to 4000 J/KG Friday afternoon, 0-
6 km bulk shear 20 to 35 kts, H7-H5 lapse rates 5.5 to 6.5 C/km. So
some stronger storms are possible once again.
Overall during the short term period expect temperatures to average
above normal with precipitation near normal to slightly above normal
as well.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
This period will be marked by unsettled conditions at each end with
a dry section in the middle between systems. Thunderstorms may be a
threat, but along with limited sunshine and atmospheric momentum,
instability will also be limited. It will feel as it should...like
the middle of summer, with moderately high humidities and high
temperatures mainly in the upper 60s to lower 80s range each day,
and lows mostly from the upper 50s to the lower and mid 60s.
&&
.AVIATION /02Z WEDNESDAY THROUGH SUNDAY/...
Upper level low now over Mohawk valley will continue to slowly
move eastward across the region this evening. Ceilings and
vsibilities will generally be VFR this evening, but scattered
showers and thunderstorms may impact the TAF sites through
midnight. Timing of showers/storms is uncertain so VCSH included
in the TAFs. Mainly VFR should occur in the evening, but areas
of fog and/or stratus are expected to develop after midnight.
best chance for fog/stratus at the TAF sites is at KGFL and
KPSF. VFR conditions all TAF sites again by 14Z Wednesday.
Winds will be light and variable tonight. By Wednesday
afternoon, winds will be out of the west around 10kts.
Outlook...
Wednesday Night: No Operational Impact. NO SIG WX.
Thursday: Moderate Operational Impact. Slight Chance of SHRA...TSRA.
Thursday Night: Moderate Operational Impact. Chance of SHRA.
Friday: High Operational Impact. Definite SHRA...TSRA.
Friday Night: Moderate Operational Impact. Chance of SHRA.
Saturday: Moderate Operational Impact. Chance of SHRA.
Saturday Night: No Operational Impact. Slight Chance of SHRA.
Sunday: No Operational Impact. Slight Chance of SHRA...TSRA.
&&
.FIRE WEATHER...
An upper level low pressure system will slowly move eastward
across the region into tonight, bringing occasional showers and
scattered thunderstorms. Thunderstorms will be capable of
producing locally heavy rainfall with flash flooding possible. A
cold front will cross the region late Wednesday bringing
another chance of showers and thunderstorms mainly across
northern areas.
&&
.HYDROLOGY...
The Flash Flood Watch has been canceled. River flows continue to
lower overnight across the Hydro Service Area.
Additional rainfall tonight will be light with less than a
quarter of an inch from any showers.
Widely scattered showers and thunderstorms will be possible
associated with a cold front passage Wednesday afternoon into
Wednesday evening. Then, more unsettled weather is expected
towards the end of the week as another low pressure system
affect the region. Showers and thunderstorms with locally heavy
rainfall will be possible again Friday afternoon into Friday
evening.
For details on specific area rivers and lakes, including
observed and forecast river stages and lake elevations, please
visit the Advanced Hydrologic Prediction Service /AHPS/ graphs
on our website.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
MA...None.
VT...None.
&&
$$
SYNOPSIS...11/Wasula
NEAR TERM...Wasula
SHORT TERM...11
LONG TERM...ELH
AVIATION...SND
FIRE WEATHER...11/JPV
HYDROLOGY...11/JPV/TAW
Area Forecast Discussion
National Weather Service Denver/Boulder CO
951 PM MDT Tue Aug 14 2018
.UPDATE...
Issued at 945 PM MDT Tue Aug 14 2018
The late afternoon and evening strong to severe storm activity
along the Front Range has diminished considerably with the last
remaining t-storms continuing to track east-southeast away from
the Denver metro area into increasingly stable boundary layer air.
Eruption of today`s hail and heavy rain storms coincided with the
passage of a shortwave trough which GOES IR/Water Vapor imagery
now show over far eastern Colorado/Nebraska Panhandle. Clearing,
albeit gradual, is now underway, although mid-level moisture
visible on 6.19 and 10.35um GOES sat loops streaming up from the
Desert Southwest may keep at least high cloud cover around
through Wednesday morning. In addition, low-level moisture
feeding up into southeast sections of the CWA may once again
result in patchy to areas of fog towards dawn. Do not believe the
fog tonight will extend as far west into portions of the I-25
corridor as it did last night. Other changes to tonight`s
forecast include only minor adjustments to wind and temperature
fields.
&&
.SHORT TERM...(This evening through Wednesday)
Issued at 222 PM MDT Tue Aug 14 2018
Thunderstorms will continue to form over the mountains and
foothills this afternoon. Once the Urban Corridor and near by
plains destabilize more, the storms will be able to progress
eastward. Latest RAP and HRRR showing CAPE of 800-1400 J/kg in the
foothills and across the Urban Corridor late this afternoon and
evening. This combined with precipitable water values around an
inch and lift from a trough over Montana and Wyoming is expected
to produce scattered thunderstorms over the mountains, foothills,
and Urban Corridor. The airmass becomes more capped and more
stable across the eastern plains. Expect storms to die off as they
move east of the Urban Corridor this evening.
For Wednesday, a boundary will be over eastern Colorado. To the
west of it, models indicate there will be drier air. Also, most of
the models keep convection south of I-70 Wednesday. However,
there should be enough convergence along the boundary, moisture,
and instability to produce a few storms. Flow aloft will increase
and produce better shear. This along with CAPE of 1000-1500 J/kg
could produce a few severe storms Wednesday afternoon over the
eastern plains.
.LONG TERM...(Wednesday night through Tuesday)
Issued at 222 PM MDT Tue Aug 14 2018
By Wednesday night the upper ridge will be over New Mexico and
extend east over the Gulf coast. Specific humidity values will
increase with PW values reaching to above an inch by late Wednesday.
For Wednesday night storms will mainly be focused over the higher
terrain of the Palmer divide with some cells being able to move over
the plains with the breakdown and northern movement of the surface
low. These storms will mainly be capable of gusty winds and small
hail.
For Thursday and Friday the upper ridge will retrograde back to the
West and North in Colorado. This will help to bring increased NW
flow over the state. A cold front will push through over the NE
plains Thursday afternoon that could produce enough CIN around peak
heating time to inhibit much convective potential outside of the
higher elevations of the mountains and foothills. Temperatures
Thursday will be hovering just around normal for this time of year
with highs in the mid to upper 80s. For Friday, some fog could be
possible over the plains during the early morning hours as moisture
will be high and temperatures slightly cooler in the post frontal
airmass. By the late morning hours a disturbance embedded in the NW
flow aloft will move over helping to introduce lift for storm
development across the plains by the late afternoon hours.
Instability is better over the far eastern plains after convective
initiation with CAPE in the 1000-1500 j/kg with just around 500 over
the Urban Corridor according to the GFS. PW values remain over an
inch with steering flow only 10-15 kts. This indicates that any
storms that do form will be slower moving and could produce a quick
half inch in less than 30 minutes under the stronger cells. Friday
will be slightly warmer than Thursday with highs in the upper 80s.
For the weekend and into the start of next week the upper ridge will
fully transition to over the western CONUS leaving Colorado in
increased NW flow. This will allow for the influx of upper waves and
fronts to bring cooler air and increased chances of showers and
thunderstorms to the region. The first shortwave will move through
Saturday into Sunday bringing storms Saturday late afternoon and
evening capable of brief heavy rain and small hail. As the shortwave
moved over forcing could continue storms overnight into Sunday. A
cold front is set to move out of WY into CO Monday ushering in
continued cooler temperatures with highs possibly in the 70s by
Monday.
&&
.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 945 PM MDT Tue Aug 14 2018
Storms for the most part have moved east of the Denver metro area
and ceilings have begun to rise with the development of a drying
south-southwest drainage wind of 5-12kts. Can`t rule out a stray
rain shower at any one of the Denver area terminals before 06z
tonight, then gradual clearing thereafter. Restrictions due to fog
are not expected tonight.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
UPDATE...Baker
SHORT TERM...Meier
LONG TERM...Bowen
AVIATION...Baker
Area Forecast Discussion
National Weather Service Fort Worth TX
856 PM CDT Tue Aug 14 2018
.UPDATE...
Only minor adjustments to the forecast were necessary this
evening to account for temperature/sky trends. Precipitation has
completely exited the area to the northeast, along with the upper
low which brought us our several days of rainfall and slightly
cooler weather. While the upper low is now centered near Kansas
City, the elongated trough axis is still draped to the southwest
through western OK and the TX Panhandle. This has contributed to
numerous severe thunderstorms developing in Central Oklahoma this
evening.
The ongoing storms in Oklahoma really are the main focus through
the short term, as it`s possible they encroach on the Red River
very late tonight. While I`ve been unable to locate a single CAM
that hints at this possibility, due northerly Corfidi vectors of
20 kts and strong WAA fields in the 925-700mb layer would suggest
there is a potential for a congealed convective cluster to make a
dive southward during the overnight hours. Recent objective
analysis indicates around 1500 MUCAPE is still available across
southern Oklahoma which a complex could ingest while fueled by
convergence at the nose of a 30 kt low level jet. Overall, it
seems the chance of convection reaching North Texas prior to
dissipating is relatively low, but not low enough to remove the
20-30% PoPs in place for our Red River counties prior to daybreak.
Will continue to monitor hourly short-term guidance for possible
southward trends in model solutions.
-Stalley
&&
.AVIATION... /Issued 636 PM CDT Tue Aug 14 2018/
/00z TAFs/
Lingering rain showers have all exited the DFW area as a band of
mid-level moisture accompanies an upper low northeastward. The
upper trough axis remains to our west, however, and is aiding in
the ignition of storms across Central Oklahoma this evening. While
some of this activity may drift towards the Red River late
tonight or early tomorrow morning, it will remain well north of
the DFW area TAF sites. The entire TAF period will consist of dry
conditions with predominantly VFR cigs. However, a few hours of
MVFR cigs around 2500 ft may materialize at Waco around daybreak
tomorrow morning. Prevailing south winds around 10-15 kts will
continue through Wednesday with SCT diurnal cumulus.
-Stalley
&&
.SHORT TERM... /Issued 357 PM CDT Tue Aug 14 2018/
/Through Tonight/
Water vapor imagery shows the upper low over the Plains quickly
pulling away to the northeast. A persistent band of strong isentropic
ascent extending from the Metroplex northeast is slowly lifting
away with precipitation coverage on a downward trend. For the
remainder of this afternoon and evening, there will still be weak
ascent associated with the larger trough spreading through North
Texas, so at least isolated showers and perhaps a thunderstorm
will remain possible. We`ll hang on to 20% PoPs mainly along and
north of I-20 through the early evening hours.
Later tonight, low level flow will veer to the southwest with a
fairly decent band of convergence setting up across Oklahoma
during the overnight hours. Showers and thunderstorms will likely
be ongoing to our north, but strong low level warm advection will
extend all the way down into the Red River counties. Despite some
drying expected to occur, there may be sufficient forcing for a
few showers and thunderstorms during the early morning hours
across our northern counties. Otherwise, partly to mostly cloudy
skies will prevail with temperatures in the mid 70s.
Dunn
&&
.LONG TERM... /Issued 357 PM CDT Tue Aug 14 2018/
/Wednesday through Monday/
After an extended period of high rain chances across North and
Central Texas, it appears that most of the region will get a
respite from the rain/storms. Areas near and north of I-20,
however, will still have the potential for convection through the
weekend as we transition to northwest flow aloft. Temperatures
will trend back towards seasonal values for areas that have seen
rain over the past couple of days and heat index values will climb
above 100 degrees.
Mild conditions will be the theme to start Wednesday morning as
low level flow will be unseasonably strong. RAP and NAM 925mb
wind progs advertise nearly 40 knots of low level flow
overspreading much of the area. While limited to some degree due
to the onset of nightfall, mixing should help temperatures stay in
the mid to upper 70s and this should diminish an appreciable fog
threat---outside of low-lying/sheltered areas. The more noteworthy
impact that the winds may have is for the sustenance of
convective cells to the south of the Red River. Higher resolution
NWP does not show much in the way of rain/storms, but given the
strong wind field and subsequent isentropic ascent, a 20 PoP as
far south as the Highway 380 corridor seems warranted. Rain
chances should wane some through the day, though I`ll keep low
PoPs along the Red River in the event that outflow lingers late
into the afternoon and becomes a focus for renewed convection. Hot
conditions will be the next story on Wednesday as a weak frontal
boundary will attempt to sag southward towards the Red River. Most
guidance keeps the front north of the Red River, but the position
of the boundary will need to be monitored. Surface winds
preceding the front Wednesday afternoon should veer slightly to
the southwest, which may help promote greater temperatures. The
recent rains should help to keep temperatures from soaring too
high, but it`ll likely feel quite humid outside with the mid-
August sun and plenty of water for evapotranspiration. High
temperatures areawide should climb into the mid to upper 90s with
heat index values up to 105 degrees in some spots.
Thursday morning should feature slightly weaker flow...but
interestingly enough...lapse rates---per the NAM---are a tad
steeper. Large scale lift from any synoptic scale feature is
pretty indiscernible right now, but there may be some slight
isentropic upglide along the Red River. While large scale
synoptic forcing looks subtle, decent lapse rates and a little
moisture can still result in some precipitation. Probabilistic
guidance from both the EPS and GEFS do not offer much in terms of
accumulated QPF along the Red River on Thursday morning and into
the afternoon, so I`ll place a silent 15 PoP across the Red River
Valley. Surface winds turn more to the southwest on Thursday which
should promote another hot day. Temperatures will climb a little
higher than Wednesday and with plenty of rain the past few
days...there should be plenty of evapotranspiration to result in
humid conditions. The warmer conditions equates to heat index
values closer to 105 degrees on Thursday.
Northwest flow aloft becomes a bit more established through the
day on Friday and both NAM and GFS guidance suggest that a compact
shortwave trough will dive southeastward and graze the Red River
zones. Given that this feature is forecast to move through during
the late morning to early afternoon hours on Friday, I`ll show a
slight chance for rain/storms a bit farther south. Forecast
soundings in the afternoon indicate that the boundary layer may
become pretty hot and well mixed...supporting a risk for strong
downburst winds. Otherwise, temperatures will be close to seasonal
values for mid-August. Heat index values will also be close to 105
degrees and if this appears likely...a small Heat Advisory may be
needed for portions of North Texas.
Saturday will feature low rain chances during the morning hours
before some slight mid-level height rises overspread from the
west. Mid and upper level clouds may continue invade from the
north which may help keep temperatures a few degrees lower.
Subsequently, heat index values are not forecast to be quite as
high during this time...with values just below 105 degrees. For
Sunday and beyond, rain chances will ramp back up as a decent
trough begins to take shape to the north and west. The best rain
chances will be initially along the Red River and across the Big
Country. There is pretty decent agreement between the
deterministic GFS and ECMWF in plowing a front through most of the
area early next week. The ECMWF is a lot more aggressive and
blasts the front all the way towards the upper TX coast while the
GFS slowly brings the front back to the north a little sooner.
Regardless of the solution, it looks like there will be another
period of below normal temperatures and rainfall for a good
portion of the area.
Bain
&&
.PRELIMINARY POINT TEMPS/POPS...
Dallas-Ft. Worth 76 96 78 98 79 / 10 10 5 10 5
Waco 76 95 76 98 77 / 5 10 5 5 5
Paris 74 90 74 95 76 / 20 20 20 20 10
Denton 75 95 77 98 76 / 20 10 5 10 10
McKinney 75 94 76 96 77 / 20 10 5 10 10
Dallas 77 96 79 98 80 / 10 10 5 10 5
Terrell 76 91 77 96 77 / 10 10 5 10 5
Corsicana 76 92 76 97 77 / 5 5 5 10 5
Temple 75 96 75 98 76 / 5 5 5 5 5
Mineral Wells 73 97 74 97 76 / 10 10 5 5 5
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
26/82
Area Forecast Discussion
National Weather Service Glasgow MT
826 PM MDT Tue Aug 14 2018
.DISCUSSION...
Evening update...
Day crew added "haze" to the grids for tomorrow: either haze or
smoke will impact visibility tomorrow (it should be noticable to
the average person that it`ll be hazy or smoky out). This will
show up with the evening update. For KGGW & KOLF, added haze to
the TAFs beginning at 6z tonight, based largely on the 25
micrograms/m^3 contour on HRRR Smoke (left it out--for now-- for
KGDV & KSDY).
Otherwise, going forecast seems to be on track with minor tweaks
to POPs in southern Prairie and southern Wibaux Counties in case
something strays in, and to temperatures.
Avery
Previous discussion...
Weak upper low over SE Montana/northern WY will drift southeast
tonight and should be in western South Dakota Wednesday. An upper
ridge will build over Montana in it`s wake allowing the airmass to
warm. This ridge will be in control of the area`s weather through
Friday then another disturbance will move through.
With the upper ridge moving in Wednesday, skies will be mainly
clear with temperatures most places in the 90s. Fire weather
concerns should be minimal as winds will be light.
On Friday, a cold front will approach the area from the northwest.
Pre-frontal compressional warming should take place and warm
temperatures well into the 90s. No 100 degree plus temps are
expected with 850 mb temps remaining below 30C.
The models are differing on the feeble chances of showers for the
weekend. The GFS being a bit fast, brings the best chances Friday
evening, while the ECMWF brings it through Saturday afternoon.
Have lowered the pops for most periods and their spacial coverage,
but keeping them for Saturday afternoon. Typically we`ll get a
moisture tap into monsoonal moisture from the desert SW, but with
a WNW flow, this will likely not happen and be kept south of us.
TFJ
&&
.AVIATION...
Flight Category: VFR, outside chance of MVFR.
Visibility: Haze or smoke coming from the fires in western
Montana, Idaho, Washington, British Columbia, and California will
lower visibilities some, which could briefly lower visibilities into
MVFR range.
Discussion: An upper ridge to our west will gradually push east
allowing for mainly clear skies. Haze or smoke will lower
visibilities some tomorrow, and possibly beyond that.
Area winds: Generally light and variable through early Wednesday,
then becoming light from the south to southeast.
Avery
&&
.GLASGOW WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
weather.gov/glasgow
Area Forecast Discussion
National Weather Service Green Bay WI
651 PM CDT Tue Aug 14 2018
Updated aviation portion for 00Z TAF issuance
.SHORT TERM...Tonight and Wednesday
Issued at 350 PM CDT Tue Aug 14 2018
Forecast concerns are scattered thunderstorms across northern
Wisconsin into the early evening, patchy dense fog overnight and
scattered showers and isolated thunder again on Wednesday.
Latest radar and satellite trends indicated a broken area of
thunderstorms along a cold front stretching from the eastern UP to
north of MSP late this afternoon. Storms have been somewhat
pulse-like in nature and overall poorly organized. Low-level moisture
pooling right along and just ahead of the front has allowed SBCapes
to creep into the 1500 to 2000 J/kg from Northern Wisconsin to
MSP with modest mid-level lapse rates. Deep layer shear is modest
generally 15 to 20 kts except right along the UP/WI border where
values are closer to 30 kts. HRRR and NAMNest are generally
similar advertising current convection to be at its strongest
between now and perhaps 23 UTC before quickly waning after sunset
given weak upper-level support. The bulk of this activity is
expected to impact mainly areas north of highway 64. The storms
are not expected to reach severe limits before dissipating, but
are capable of producing perhaps some small hail and brief gusty
winds especially across far northern Wisconsin for the next
couple of hours.
Weak surface boundary is forecast to slowly drop south into
central and eastcentral Wisconsin on Wednesday morning. In
addition, weak nearly cutoff upper-level low pressure will also
drift into southwest Wisconsin by late morning with boundary layer
winds turning SE ahead of it. The combination of these features
should locally enhance low-level convergence across central
Wisconsin by midday. Combination of more focused low-level
convergence, residual low-level moisture and increasing
insolation later in the morning, should allow for a disorganized
area of showers and isolated thunderstorms to develop around
midday Wednesday. Again, deep layer shear will be weak thus storms
are expected to be disorganized and pulse-like in nature with
brief heavier downpours possible.
Overnight tonight, patchy dense fog is also possible once again
mainly across northern and central sections especially in areas
that receive some appreciable rainfall this evening.
.LONG TERM...Wednesday Night Through Tuesday
Issued at 350 PM CDT Tue Aug 14 2018
Not expecting any high impact weather through much of the extended
forecast. There may be a few showers and thunderstorms over next
couple days, with a better chance of more widespread showers and
thunderstorms very late in the weekend into early next week. Near
normal temperatures can be expected through Thursday before above
normal temps arrive over the weekend. Late in the forecast period,
trends are toward temperatures that cool to near normal early
next week.
Wednesday night through Thursday night: This time period will
consist of increased cloud cover along with intermittent rain
showers. Overall instability looks to be lacking, which would only
favor a few afternoon rumbles of thunder, mainly if there are any
breaks in the cloud cover. The main driver of these rain showers
and possible thunderstorms will be a couple shortwave troughs
expected to slide through the area. The first wave is expected to
slide through northern Illinois Wednesday night into southern
Lower Michigan by Thursday morning. Thursday afternoon would be
the next chance, and probably the best chance, of seeing some pop
up afternoon rain showers and perhaps a rumble of thunder;
however, the CWA is expected to between two shortwaves at that
time, yet still in a general troughing pattern. The next
shortwave, is progged to slide mainly to the south of the CWA
Thursday night, perhaps only bringing a small chance of rain
showers to the Fox Valley. Not expecting a drought buster, just
some generally light rain showers. Highs will be near normal for
this time period with highs mainly in the 70s and overnight lows
in the 50s to around 60.
Friday through Sunday: The main trough axis and the aforementioned
shortwaves will shift off to the east of the area through this
time period. This will allow for a ridging pattern to set up
across the CWA, both aloft and at the surface. Winds will remain
light and there may be some radiation fog formation at night with
clear skies and calm winds, especially inland. Daytime highs will
be above normal with most locations expected to reach into the
80s, while overnight lows are expected to drop into 50s to around
60.
Sunday night through Tuesday: Things will become more active for
this time period as a broad troughing pattern is expected to dig
into much of the central and eastern CONUS. This is indicated by
each of the long-range models. There continue to be some
differences in timing, so exact detail will need to be pinned down
closer to this rain event. Models currently have an associated
cold front that would slide through the area Sunday night through
early Monday afternoon. The timing difference is largely between
the EC/GFS, where the GFS is more progressive at moving the front
through the CWA. This is something to monitor, as seems to rush
things a bit faster later in the summer season into the early
fall. Regardless, Sunday into Monday, looks to be fairly
unsettled. Subsidence associated with high pressure on the back
side of the front, will allow for clearing conditions and quieter
weather Monday night into Tuesday. Temperatures will cool to
normal or possibly a bit below, depending on how strong/deep the
trough is across the area.
&&
.AVIATION...for 00Z TAF Issuance
Issued at 650 PM CDT Tue Aug 14 2018
As of 23Z a cold front was stalled across northern Wisconsin and
showers and thunderstorms in the north were weakening or moving
out of the forecast area. There should be a period of quiet
weather once the showers and storms have departed, but fog is then
a concern due to light winds. Cloud cover could hamper fog
development, but this afternoon`s rainfall may counter that
across the north. Kept the mention of fog at all TAF sites that
was in the previous forecast. Precipitation timing and potential
are the main concerns on Wednesday as a mid level short wave
approaches from the southwest. Mesoscale models bring convection
into the area from the southwest during the morning as more
showers and storms fire in the vicinity of the frontal boundary.
The morning rain is then forecast to push east as more
significant convection fires in central Wisconsin during the
afternoon. Confidence in the timing and exact location of
Wednesday`s showers and storms is low.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM.....ESB
LONG TERM......Cooley
AVIATION.......MG
Area Forecast Discussion
National Weather Service Medford OR
901 PM PDT Tue Aug 14 2018
.DISCUSSION...No big updates required this evening. Weather is
fairly quiet this evening but not lacking impact. Smoke is thick
in many areas tonight, after another day of fire activity around
the region. Air quality in Medford is now in the "hazardous"
category, one of the highest PM2.5 readings we`ve registered.
Better but still unhealthy conditions are being observed towards
the coast and east of the Cascades. The latest HRRR smoke model
run, and atmospheric conditions, suggest smoke will linger near
the surface overnight, so don`t expect much improvement.
Thunderstorm threat is the other main element we`re focusing on.
Midlevel moisture is evident on the evening satellite imagery over
Northeastern California. No lightning has been observed yet, but
convection-allowing models suggest that thunderstorms are possible
east of the Cascades by early Wednesday morning. Particularly
bullish on the thunderstorm threat later tonight are the NAM Nest
and HRW NSSL models We are maintaining a Red Flag Warning from
the Cascades eastward and in Northeastern California from now
through Wednesday evening. Further west, there is greater
uncertainty in lightning potential, and we have a Fire Weather
Watch continuing there for Wednesday.
Smoke coverage and intensity looks like a repeat of today`s
situation, pending fire activity of course.
Please see the previous discussion below for more details on the
smoke and thunderstorms.
&&
.AVIATION...For the 15/06Z TAFs...Along the coast widespread
IFR/LIFR cigs and MVFR/IFR visibilities will persist through
Wednesday with gradual erosion of coverage in the coastal valleys
during the late morning and afternoon.
Inland, for the Umpqua Basin, VFR conditions are expected throughout
the TAF period. Elsewhere inland, widespread smoke from area
wildfires is resulting in reduced visibilities. MVFR vsbys with
local IFR vsbys will persist through the TAF period. -DW
&&
.MARINE...Updated 800 PM PDT Tuesday, 14 August 2018...Relatively
light winds and seas are expected through tonight. Coastal fog and
low stratus will continue into Wednesday. Building northwest swell
is expected Wednesday. A thermal trough will redevelop along the
coast on Thursday, producing gusty north winds and steep seas into
this weekend. Small craft advisory conditions are likely, with
afternoon and evening gales possible Friday and Saturday south of
Cape Blanco. Conditions are expected to improve early next week. -
CC/DW
&&
.FIRE WEATHER...Updated 100 PM PDT Monday, 13 August 2018... The
main focus for this forecast cycle was on the potential for dry
thunderstorms tonight and Wednesday east of the Cascades. The most
recent model data shows more of a consensus of elevated convection
firing off during the late this evening in northern California and
working its way northward and westward to the Cascade Crest into the
early morning hours of Wednesday. Also looked at the air mass
profile over northern California and southern Oregon east of the
Cascades, and there is definitely moisture aloft with a typical
inverted V sounding up to 550 mb or so.
Given a consensus for some isolated nocturnal thunderstorms with LAL
6 combined with near-record dryness, decided to continue the Red
Flag Warning was appropriate for Fire Weather Zones 284 and 285 in
California and Oregon Fire Weather Zones 624 and 625. We extended
the area of the Red Flag Warning to include most of fire zone 623
and the far eastern portion of fire zone 617. We have also extended
the timing of the Red Flag Warning for California Fire zones 284 and
285, to cover the entire thunderstorm event.
There may be a break in thunderstorms Wednesday afternoon. However,
by Wednesday evening, the isolated dry thunderstorm chances will
return to those zones, so decided it made more sense to keep the
warning going through the entire event.
West of the Cascades, there is more moisture available for
convection to initiate on Wednesday, but smoke may inhibit surface
based thunderstorms. That being said, there is plenty of elevated
energy that this shortwave can tap into to create more elevated and
dry storms. Regardless of wet/dry thunderstorms, any lightning
should be sufficient to see new starts. Thus, we are leaving the
Fire Weather Watch for FWZ 280, 281, 621, 622, and most of 617.
Thunderstorms are also in the forecast for the majority of the
forecast area Wednesday except the coast and the Umpqua region.
We won`t be completely done with thunderstorms Thursday, since the
upper trough/low offshore will be slow to move inland. We have kept
thunder chances in the mountains and over portions of northern
Klamath and Lake Counties, but the dry thunderstorm threat will
largely diminish.
The upper trough/low should push through Friday and it should dry
out and turn hotter again this weekend. Gusty southwest winds are
expected across Modoc County and the relative humidities will be
typical for this time of year. This means that conditions will be
near critical on Thursday afternoon for fire zone 625. Otherwise,
there is some potential for a period of offshore NE winds over SW
Oregon and the western Siskiyou County mountains Friday into
Saturday as a thermal trough sets up in northern California.
-Schaaf
&&
.PREV DISCUSSION... /Issued 243 PM PDT Tue Aug 14 2018/
DISCUSSION...Some tweaks were made to the going forecast today,
but the general forecast remains the same. An upper low is
positioned off the coast this afternoon, and we are under the
influence of the south-southwest flow ahead of this feature.
Moisture can be seen streaming northward toward us, and cumulus
are already developing over northern California. Mid level
moisture continues to rise tonight, and as a result, instability
aloft also increases. Capes of 500+ J/KG are common on east side
soundings tonight, and this is fairly impressive elevated
instability for around here at night.
Models remain somewhat split on the timing and strength of the
last necessary ingredient: a trigger. It`s hard to make out any
short wave activity over NorCal on this afternoon`s water vapor
imagery, but it`s also not too hard to imagine something in there
as there are fields of ACCAS on visible imagery. The GFS shows a
rather broad area of vorticity moving over us tonight, whereas the
NAM shows a more robust short wave arriving around dawn tomorrow.
Both models key in on convective potential from eastern Siskiyou
County northward into the Klamath Basin late tonight. Furthermore,
forecast soundings show very dry low layers (inverted-V) with
cloud bases at around 10,000 feet, and this indicates that any
storms that do develop are very likely to be dry. As a result,
we`ve pulled the area of isolated dry thunderstorms further
westward tonight to around the Cascade crest and expanded the red
flag warning to cover it.
What storms do form overnight are likely to slide northward
through the morning, and then there may be a break during the
afternoon hours. However, models are consistent in showing another
outbreak of convection late tomorrow afternoon and evening. This
is again expected to be focused from the Cascades east, but the
GFS continues to show the potential for some storms on the west
side late in the day. Surface based instability could easily be
limited by smoke coverage (which blocks sunlight and reduces
instability), so storms west of the Cascades are by no means
certain. Nevertheless, ignition efficiency is likely to be very
high, and thus any lightning strikes would be problematic enough
that, in our judgment, it`s worth keeping a fire weather watch in
place. To complicate matters even further, any storms on the west
side will have more moisture to work with and thus could be on
the wetter side IF they are able to tap into boundary layer
moisture, but if smoke limits surface instability and they storms
remain elevated, they would be on the dry side.
As the upper trough begins to come inland later Thursday, we could
see a repeat of thunderstorms in roughly the same areas. However,
unlike tomorrow, drier air starts working in from the south on the
east side and instability on the west side decreases Thursday. As
a result, we`ve generally limited storm potential to our northern
Cascades and across the more lightning prone areas of northern
Klamath. As the trough moves over and then east of us Friday,
conditions should stabilize, and we`ve kept the forecast dry for
Friday. However, a trough moving through will probably bring gusty
west winds, especially to east side locations. Thus, we lose one
threat (lightning) and add another (wind) on Friday.
Few changes were made to the extended forecast. A ridge moves in
behind the trough this weekend and that will bring hotter, drier
weather again. This also looks like a thermal trough setup which
means offshore (northeast) winds and poor night time humidity
recoveries in the coastal mountains. Models then show another
upper low coming in early next week, but this one will probably be
to our north, which is a dry, albeit cooler, weather pattern for
our area. -Wright
&&
.MFR WATCHES/WARNINGS/ADVISORIES...
OR...Red Flag Warning until 11 PM PDT Wednesday for ORZ617-623>625.
Fire Weather Watch from 5 AM PDT Wednesday through Wednesday
evening for ORZ617-621>623.
CA...Fire Weather Watch from 5 AM PDT Wednesday through Wednesday
evening for CAZ280-281.
Red Flag Warning until 11 PM PDT Wednesday for CAZ284-285.
Pacific Coastal Waters...None.
$$
Area Forecast Discussion
National Weather Service San Francisco Bay Area
855 PM PDT Tue Aug 14 2018
.SYNOPSIS...Temperatures will remain near to slightly below
seasonal averages through Wednesday with widespread night/morning
low clouds. High pressure will build toward the West Coast by late
week and result in a gradual warming trend, especially over the
interior.
&&
.DISCUSSION...as of 8:54 PM PDT Tuesday...A relatively deep
marine layer, currently between 1800-2000 feet per the Fort Ord
Profiler and a moderate onshore gradient maintained stratus
coverage over portions of the coast and locally inland through the
day today. As a result there was a mixed bag of temperatures this
afternoon. Some areas that came in contact with the cool marine
air and low clouds cooled while locations that were well inland or
above the marine layer saw little to no change. Temperatures
topped out in the upper 50s and 60s along the coast, 70s to 80s
inland with a few 90s in the warmest interior valley locations.
Another night of widespread stratus and patchy drizzle is
anticipated tonight as the marine layer continues to deepen as a
trough of low pressure situated off the west coast deepens.
The forecast remains on track. No updates expected this evening.
From previous discussion...The ridge of high pressure over the
Desert Southwest will strengthen slightly and compress the marine
later a bit by Wednesday afternoon. Thus, look for a slight
warming trend for inland areas, especially across the East Bay and
South Bay. Additional warming is likely for the interior late in
the week as the ridge builds westward toward the California Coast.
With warming 850mb temperatures, the interior will likely see
afternoon highs back above seasonal averages with seasonable
conditions near the coast.
Little change is forecast into the upcoming weekend and early
next week as the weather pattern remains dominated by the
mid/upper level ridge. Thus, near to above normal temperatures
inland with mostly sunny conditions each afternoon. Coastal areas
will be closer to seasonal averages with periods of night/morning
low clouds and patchy fog as a result of the marine layer and
onshore flow.
&&
.AVIATION...as of 04:36 PM PDT Tuesday...for 00Z TAFs. Stratus
remains along much of the coast and over the Monterey Peninsula as
the marine layer sits at around 2000 ft. Areas not currently
experiencing BKN to OVC conditions can expect to see a return of
low clouds by early this evening. MVFR/IFR cigs should move inland
and down the valleys again this evening and overnight for all
sites. Another round of late clearing can be expected tomorrow.
Confidence is low on clearing time.
No major smoke concerns as the latest HRRR shows less vertically
integrated smoke over the Bay Area tonight and tomorrow morning.
Breezy onshore winds will subside again tonight and tomorrow
morning before increasing again in the afternoon, especially at
KSFO.
Vicinity of KSFO...MVFR cigs expected to continue this afternoon
and evening before lowering to IFR tonight. Confidence on
clearing time tomorrow is low, but expecting SFO to be under BKN-
OVC skies through at least 21z. Winds will reduce this evening and
overnight before onshore winds pick up again tomorrow afternoon.
SFO Bridge Approach...Similar to the terminal.
Monterey Bay Terminals...KMRY should remain under MVFR cigs the
rest of the afternoon and evening before lowering to IFR for the
night. Another early return of stratus is forecast for KSNS. It is
possible that once again KMRY could remain under BKN-OVC
conditions all day tomorrow with cigs raising to MVFR late
tomorrow morning. Generally light winds through the period.
&&
.MARINE...as of 8:45 PM PDT Tuesday...Generally light to moderate
northwest winds will continue across the coastal waters tonight
and tomorrow with locally gusty winds along the Big Sur Coast
south of Point Sur. Northwest swell will remain mild while the
southerly swell will gradually increase throughout the week.
&&
.MTR WATCHES/WARNINGS/ADVISORIES...
.Tngt...SCA...SF Bay until 9 PM
SCA...Mry Bay until 9 PM
SCA...Pigeon Pt to Pt Pinos 0-10 nm until 9 PM
SCA...Pt Pinos to Pt Piedras Blancas 0-10 nm
&&
$$
PUBLIC FORECAST: CW
AVIATION/MARINE: AS
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Area Forecast Discussion
National Weather Service New York NY
955 PM EDT Tue Aug 14 2018
.SYNOPSIS...
Low pressure will pass to the north through tonight, followed by
weak high pressure on Thursday. A warm front will then approach
and lift through early Friday, followed by a cool front Friday
night into Saturday. The front will then settle just offshore
this weekend as weak low pressure rides along it. High pressure
will briefly return on Monday before another frontal system
approaches from the Plains states.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
Shower activity is at a minimum right now, so only slight chance
for the entire area until 10-11 pm when western sections of the
area will start to see a chance for showers from an approaching
area of showers moving in from northeaster Pennsylvania and
souther New York. The HRRR seemed to have a good handle on it,
so POPs are largely from that model. Otherwise, forecast is on
track.
The low pressure system progresses northeastward overnight.
Showers will diminish gradually tonight and thunderstorms will
be isolated and over the ocean where more instability will be
located. Instability is expected to decrease through the night
with upper level trough axis moving through and best lift area
shifting southeast of Long Island. Breaks in the clouds
overnight could lead to areas of fog with generally light winds
and plentiful moisture as temperatures fall into the mid 60s
north and west to low 70s across Long Island, NYC and along the
coast.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH THURSDAY/...
Models continue to be in good agreement with the 500mb low will
push east of the forecast area Wednesday. Drier air will
continue to filter in behind this system as dewpoints will be
dropping into the 60s. With high pressure ridging Wednesday into
Wednesday night, expect mostly clear to partly cloudy skies.
Forecast 850mb temps of 16C-17C combined with a westerly flow
will result in max temps in the upper 80s to low 90s across most
spots. With the lower dewpoints, expect heat indices just a
degree or two higher than the actual temperature. Isolated 95
degree heat index values could occur in the city and immediate
surrounding suburbs, but not enough coverage for heat advisory
consideration.
Ridging aloft will begin to break down Thursday with max
temperatures a degree or two warmer. This could result in heat
indices of low to mid 90s in and around the city. Minimum
temperatures will remain in the low to mid 70s for most areas
outside of northwestern counties.
There is a moderate risk of rip current development at the ocean
beaches on Wednesday.
&&
.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
The ridge aloft will continue to break down and push offshore
Thursday night in response to a shortwave advancing across the Great
Lakes. As the associated surface low tracks across the lakes on
Friday, a warm front will lift north of the region early in the day,
followed by a cold frontal passage late Friday night into Saturday
morning. Shower and thunderstorm chances will increase through the
day, with heavy rain possible at times as precipitable water values
again increase to around 2 inches.
The front then settles just offshore during the day on Saturday.
With energy lingering in the upper trough, this will result in at
least the potential for unsettled weather to continue through the
weekend. In addition, there are some indications that a shortwave
over the Midwest develops a surface reflection as it emerges off the
Mid Atlantic coast during the day on Sunday. At this point it
appears that the bulk of the precipitation would remain south of the
region late Sunday into Monday as that low rides northeastward along
the old frontal boundary. Ridging then briefly builds back into the
region during the day on Monday ahead of the next frontal system
tracking eastward from the Plains.
Temperatures on Friday and Saturday will continue to run several
degrees above normal before falling back to near normal for the
remainder of the long term period. With highs in the upper 80s to
around 90 across much of the region on Friday and plenty of
humidity, heat indices could rise into the mid to upper 90s across
much of northeast New Jersey, New York City, and Long Island.
&&
.AVIATION /02Z WEDNESDAY THROUGH SUNDAY/...
An upper level low will pass to the north tonight. Weak high
pressure will then build in on Wednesday.
VFR for the TAF period, with just a few evening showers left
over from daytime convection. S-SW winds mainly less than 10 kt
should shift W-WNW overnight, then increase to around 10 kt with
gusts 15-20 kt late morning and afternoon. Coastal sites should
see at least some partial sea breeze influence, with winds
either backing entirely to 240-250 true or fluctuating between
240-290 true.
...NY Metro Enhanced Aviation Weather Support...
Detailed information, including hourly TAF wind component fcsts,
can be found at: http:/www.weather.gov/zny/n90
KJFK TAF Comments: Wind direction Wed afternoon could fluctuate
between 240-290 true.
KLGA TAF Comments: No unscheduled AMD expected.
KEWR TAF Comments: No unscheduled AMD expected.
KTEB TAF Comments: No unscheduled AMD expected.
KHPN TAF Comments: No unscheduled AMD.
KISP TAF Comments: Wind direction late Wed afternoon could
fluctuate between 240-290 true.
.OUTLOOK FOR 00Z THURSDAY THROUGH SUNDAY...
.Wednesday night-Thursday...Mainly VFR.
.Friday...MVFR or lower conditions possible in late day/evening
showers/tstms from the NYC metros north/west.
.Saturday and Sunday...VFR or lower conditions possible in
showers and thunderstorms.
&&
.MARINE...
A brief period of increasing SW flow into early Wednesday could
build ocean seas close to 5 ft farther offshore. Gusts should
remain under 25 kt.
Weak high pressure builds Wednesday night through Thursday night
with relatively tranquil winds and seas. Southerly winds
increase Friday night ahead of low pressure and a cold front. At
this time, winds and seas are expected to remain below SCA
thresholds.
&&
.HYDROLOGY...
Showers will taper tonight as low pressure shifts east. Dry
conditions on Wednesday and Thursday will allow a bit of a
reprieve, but an approaching frontal system could produce
showers/tstms with heavy rain Friday afternoon and evening. Deep
layer SW flow nearly parallel to the approaching frontal
boundary will increase moisture over the region with PW
expected to reach over 2 inches. There is potential for heavy
rain with individual cells and also training of cells, mainly
from the NYC metro area north/west.
&&
.TIDES/COASTAL FLOODING...
A coastal flood statement continues for tidal locations along
southern Nassau and southern Queens, along the south shore back
bays. Expect astronomical high tide levels will near minor
flooding tonight.
&&
.EQUIPMENT...
NYC NOAA Weather Radio Station KWO-35 (162.55 MHz) remains off
the air for an extended period of time.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
NJ...None.
MARINE...None.
&&
$$
SYNOPSIS...FEB/99
NEAR TERM...JM/JP/99
SHORT TERM...99
LONG TERM...FEB
AVIATION...Goodman
MARINE...FEB/99
HYDROLOGY...FEB/99
TIDES/COASTAL FLOODING...
EQUIPMENT...
Area Forecast Discussion
National Weather Service Mount Holly NJ
944 PM EDT Tue Aug 14 2018
.SYNOPSIS...
The large low pressure system that has been responsible for the
heavy rain in the area the last few days will continue to slowly
lift northeast overnight away from the region. This will be followed
by weak high pressure tomorrow. By Friday, another low crossing from
the Great Lakes region into New England will bring a cold front into
our region. This front is expected to stall over our region for much
of the weekend before shifting southeast Sunday night or Monday.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
930 pm update: Main adjustments to the forecast were modifying
evolution of decreasing PoPs across the area. The biggest change
was to areas near/north of I-80, where a batch of rain and
embedded thunder was moving in from northeast Pennsylvania. Hi-
res models have handled this poorly this evening, but the latest
HRRR seems to suggest it diminishing gradually through or just
after midnight. The precipitation has caused flash flooding in
south-central New York and adjacent far northeast Pennsylvania.
Current expectations are that the precipitation will diminish
sufficiently so that the flash flood threat is low in our CWA.
Nevertheless, given the antecedent very wet conditions across
the area, cannot rule out a localized flooding problem with this
precipitation, especially if it maintains intensity longer than
progged.
Previous discussion...
A clear spin in the atmosphere was evident this afternoon on
regional mosaic radar and GOES-16 satellite loops in association
with a closed upper low over the Catskills region in upstate NY.
This places our region under the dry slot and in westerly flow to
the south of the cyclone. However, this dry slot is not very dry as
the plume of tropical moisture that was drawn poleward ahead of this
system has wrapped around the low, resulting in PWATs that are near
or slightly above climo (1.5-1.75").
Sufficient moisture and diurnal instability combined with several
sources of lift, has lead to another episode of showers and storms
this afternoon. Convection was loosely organized earlier this
afternoon but has since organized a bit into at least three broken
line segments: (1) along a pre-frontal surface trough that was over
the I-95 corridor at the moment and (2)/(3) a trailing shortwave
troughs located over north-central and eastern PA. This means
several rounds of showers and storms will affect eastern PA and NJ
through the remainder of the afternoon and into the evening. The
bulk of this activity this afternoon may pass to the north of
Delmarva but the trailing convection could advance farther south
into these southern zones this evening.
Heavy downpours with these showers and storms are producing a quick
one- to three-quarters of an inch but a steady storm motion (east at
10-20 mph) has limited the duration of the heavy rain and the threat
of flash flooding. Nonetheless, poor drainage flooding is still a
possibility for locations that see multiple rounds of brief heavy
downpours and are particular flood prone due to the recent heavy
rainfall. Under the assumption that storms don`t organize along a
more west-east line (parallel to storm motion and favorable to
training), the risk for flash flooding will be low.
Showers and storms will diminish in coverage and intensity after
sunset, but an isolated shower is still possible early into the
overnight. A light west wind and cloud cover should limit the
development of fog (in terms of coverage and density). However,
patchy fog cannot be ruled out in the rural valleys if cloud breaks
do develop.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH 6 PM WEDNESDAY/...
The upper trough will move off the New England coast while the
attendant cold front progresses farther off the Mid-Atlantic coast.
An upper shortwave ridge initially positioned west of the
Appalachian spine in the morning will build eastward toward the area
through the day.
The aformentioned ridge may be far enough upstream of our area to
guarantee one of those fleeting days without any showers or storms.
The possibility for a weak shortwave disturbance riding atop of the
ridge, development of a pressure trough and terrain circulations
could provide a source(s) of lift for convective initiation during
peak heating hours, mainly across the higher terrain and northern
tier of the CWA (I-78 north). Coverage (PoPs) are forecast to be
highest late in the afternoon but limited to low chance (30 percent)
across the southern Poconos and isolated (20 percent) elsewhere N/W
of the fall line and Mason-Dixon line.
WAA in wake of the exiting trough in addition to strong daytime
heating and downsloping flow will all contribute to a warming trend
compared to recent days. Highs in the lower 90s are forecast for the
urban I-95 corridor and coastal plain with upper 80s more common
farther inland in the higher terrain.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH TUESDAY/...
Summary...Relative calm Wednesday night and Thursday will be short
lived as another low pressure system will bring more chances for
rain Friday through the weekend. We may have another period of
tranquil weather on Monday, before a stronger cold front could bring
another round of storms Tuesday or later.
Details:
Wednesday night and Thursday...A mid level ridge is expected to
progress east through this period, although it will be weakening as
it does so. Therefore, the period should be starting out mostly dry,
though some showers and storms could encroach on region from the west
on Thursday as the next low begins to develop. With Thursday
starting off mostly sunny, and dew points expected to remain in the
lower 70s, we will see hot and muggy conditions during the day
Thursday. Current forecast has conditions below heat advisory
criteria, but will continue to monitor this as we get closer.
Friday through Sunday...Developing low over the Great Lakes region
will progress towards New England through the weekend. This low will
bring a cold front into our region on Friday. However, it still
looks likely that this front will stall over our region for much of
the rest of the weekend. Consequently, expect continued chances for
showers and storms through the weekend, especially on Friday and
Friday night. However, thankfully, it looks like we should have
faster storm motions limiting the flooding threat, although
precipitable water values remain quite high. Temperatures through
this period will be very dependent on where the front eventually
stalls. Especially on Friday, we could see a large temperature
gradient across our region with the coastal plains once again in the
lower 90s (heat index values near 100), while the southern Poconos
may struggle to reach 80.
Monday...Mid and upper level short wave ridge is expected to quickly
propagate east over our region resulting in a mostly dry day.
Tuesday and beyond...This will be a period worth watching as almost
all of the operational models are depicting a stronger cold front
approaching our region from the west. There remain some major timing
differences (the GFS doesn`t depict this front coming through at all
through the first half of the week, while the ECMWF has it through
the region Tuesday night), but if this pattern continues, this could
finally bring in much drier air (after a period of showers and
storms along and just ahead of the front).
&&
.AVIATION /02Z WEDNESDAY THROUGH SUNDAY/...
The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY and surrounding areas.
Tonight...Generally VFR, though some patchy fog cannot be ruled
out at the terminals late tonight. For now, confidence is too
low for inclusion in the TAFs. Additionally, watching
precipitation to the northwest of KABE closely. Currently,
think the best chances are north of the terminal, but may need
to include some precip and at least temporary lower CIGs/VSBYs
should this persist longer and progress farther southwest than
anticipated. Any lingering precipitation should diminish after
midnight. Light west winds. Low confidence.
Wednesday...VFR with west winds 5 to 15 kts, perhaps with a few
gusts to 20 kts or so. Moderate confidence.
Outlook...
Wednesday night...VFR conditions expected with light westerly winds.
Patchy fog may develop near more rural TAF sites, but chance for
this occuring is low. High confidence on the rest of the forecast
elements.
Thursday through Sunday...Predominantly VFR with temporary
visibility and ceiling restrictions if any showers and thunderstorms
affect a TAF site. The highest risk for this occuring is on Friday
and Friday night. Southwesterly wind will be shifting to northerly
and eventually northeasterly Saturday night into Sunday as a cold
front sinks south.
&&
.MARINE...
W-SW winds 10-15 kt with gusts to 20 kt are occurring this afternoon
in the DE Bay and coastal Atlantic waters. Meanwhile seas around
around 4 ft in the coastal waters. Expect these conditions to
continue into this evening except for a wind shift to W or even W-NW
will occur behind a front around or shortly after sunset. A pressure
surge behind the front could also yield gusts near 25 kt (SCA
criteria) but it should only last for an hour or two per model
forecast soundings. Accordingly a SCA was not issued. Isolated to
scattered storms over land should reach the NJ waters late this
afternoon. Isolated gusts at or above 30 kt are possible and could
necessitate Special Marine Warnings. Another broken line of storms
even farther inland may reach the waters closer to sunset but it is
uncertain if the intensity will hold together by the time it reaches
the coastal waters.
W winds 10-15 with gusts to 20 kt are expected on Wednesday.
Outlook...
Thursday...Winds and seas should stay below SCA criteria.
Friday...Southerly winds on the Atlantic waters will be increasing
and could gust above 20 KT at times. Seas will subsequently increase
as well. However, at this time it looks likely that both winds and
seas will stay just below SCA criteria.
Saturday and Sunday...Winds will gradually shift to westerly and
then abruptly shift to northerly and northeasterly Saturday night
into Sunday. behind this cold front, wind gusts to 25 kt and seas
approaching 5 feet are possible.
Rip Currents...
A low risk for the development of dangerous rip currents is expected
for the remainder of this afternoon and Wednesday as the flow
remains offshore.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...None.
NJ...None.
DE...None.
MD...None.
MARINE...None.
&&
$$
Synopsis...Johnson
Near Term...CMS/Klein
Short Term...Klein
Long Term...Johnson
Aviation...CMS/Johnson
Marine...Johnson/Klein
Area Forecast Discussion
National Weather Service Pueblo CO
329 PM MDT Tue Aug 14 2018
.SHORT TERM...(This evening through Wednesday)
Issued at 329 PM MDT Tue Aug 14 2018
Currently...
Scattered showers and -TSRA were noted at 2 pm, mainly along and
just east of the contdvd. More isold storms were just north of
Teller county. Flow aloft has transitioned to northwesterly, and
storms were moving southeast. Weak effective shear was noted
(~25kts) and CAPE was running about 500-1000 J/KG.
Over the lower elevation`s, skies were mostly clear. Temps were in
the U70s to L80s, with similar temps in the larger valleys.
Rest of Today and into Tonight...
Storms will continue to increase in coverage and intensity as they
move southeast across the higher terrain and then onto to the
Plains. Latest hi res guidance has been indicating storms may be a
bit stronger as they move onto the lower elevations and may make it
onto the plains for 10s of miles before dissipating generally west of
the longitude of KLHX. I cant rule out a marginally severe storm but
most of the activity will not be all that strong. Main concern will
be the burn scar areas, and the potential for flash flooding.
Lightning is always a concern with any thunderstorm.
By mid to late evening activity is expected to end. HRRR is a bit
more robust in keeping storms going (especially up in the Pikes Peak
area), but I think this may be a bit overdone.
The predawn hours should be mostly clear, with min temps falling
into the U50s to around 60F plains, 40s and 50s valleys and 30s
mtns.
Wednesday...
Could see some marginally severe storms tomorrow. Better chance of
strong convection tomorrow as a fairly decent jet streak comes
across the area associated with a shortwave dropping southeast in
the NW flow aloft. CAPE values should range to about 1000-1500 j/kg
and shear of 30-35 knots should allow for some rotating convection
capable of producing some hail up to silver dollars and wind gusts
to 60 mph. Most favorable conditions will be just east of the
interstate extending out towards the border. Over the far eastern
plains CAPE starts to rapidly drop off, so storms may weaken as they
approach the KS border.
Burn scar flooding cant be ruled out tomorrow but CAPE values may be
lacking across the higher terrain to promote heavy rainfall.
Otherwise, expect another warm day across the region with mostly
L90s across th plains with 80s in the greater COS region and in the
valleys.
.LONG TERM...(Wednesday night through Tuesday)
Issued at 329 PM MDT Tue Aug 14 2018
Thursday appears to be another active meteorological day(in the
form of some stronger storms as well as storms with heavy rain
potential) across the majority of the forecast district(especially
from mid-afternoon into the evening) as above average atmospheric
moisture(per PW analysis near 1.20 across portions of the I-25
corridor) interacts with a subtle upper disturbance(per PV
analysis) and a northeasterly to easterly surface surge.
Friday has the potential to be somewhat less active over eastern
portions while western locations should continue to experience
scattered shower and thunderstorm activity.
It still appears that this weekend has the highest potential of
experiencing more widespread and potentially intense storm
activity as unseasonably strong upper disturbance(per PV/jet
analysis) and northerly surface surge impacts the forecast
district. For example, over eastern locations, projected localized
capes, LI`s and deep-layer shear values exceeding 1500 J/KG, -6C
and 45 knots respectively are anticipated at times from Saturday
afternoon into Saturday night.
Then, will continue with theme of primarily afternoon into evening
shower and thunderstorm activity(generally favoring higher
terrain locations) Monday and to a lesser degree Tuesday as strong
upper ridge develops near the 4-corners region by Tuesday night.
Finally, near to above seasonal mid-August maximum temperatures
are projected to continue over the forecast district from Thursday
into Saturday, with below seasonal temperatures then anticipated
from Sunday into next Tuesday.
&&
.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 329 PM MDT Tue Aug 14 2018
A passing thunderstorm cant be ruled out at each of the TAF sites
later this afternoon/early evening and tomorrow afternoon/early
evening. Best chance of storms will be over KCOS with lesser chances
over KALS and KPUB. Otherwise expect VFR conditions and generally
light winds (expect vcnty TSRA).
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
Area Forecast Discussion...UPDATED
National Weather Service Shreveport LA
939 PM CDT Tue Aug 14 2018
.UPDATE...
Strong to severe thunderstorms persist across Central Oklahoma.
Most of the models seem to have initialized poorly (wrong
location of ongoing storms) or exhibit easterly storm motions
versus southeasterly, which is what is being observed on radar.
Among the various guidance, the HRRR appears to be the only one
even close to the current situation. Even though latest radar
loops appear to show some weakening along the leading edge of the
storms, they also appear to be congealing into more of a solid
complex. Latest mesoanalysis also suggests there is enough
instability across Southern Oklahoma to maintain the convection
for several more hours, but a gradual weakening trend is expected.
Long story short, there is still a chance for storms to affect
Southeast Oklahoma and adjacent portions of extreme Southwest
Arkansas and Northeast Texas after midnight. Therefore, current
PoPs will be maintained.
Overall, the vast majority of the forecast was kept intact. Minor
updates were made to some of the hourly grids based on observed
trends.
CN
&&
.PREV DISCUSSION... /issued 701 PM CDT Tue Aug 14 2018/
AVIATION...
For the 15/00z TAFs, abundant mid and high level cloud cover will
persist for much of the overnight hours but should decrease in
coverage somewhat during the night. Patchy stratus may lead to
MVFR conditions across portions of East Texas and Western
Louisiana for a few hours around sunrise Wednesday morning. This
includes KSHV, KGGG, KTYR, and KLFK. Flight conditions should
improve by mid to late morning, and VFR conditions should then
prevail for the duration of the period. Southwesterly surface
winds will also increase to between 10 and 15 kts in most
locations after 15/12z. There may be some gusts near 20 kts at a
few sites, particularly across East Texas.
CN
PREV DISCUSSION... /issued 426 PM CDT Tue Aug 14 2018/
SHORT TERM...Tonight through Wednesday Night/
Upper level low continues to lift northeastward across eastern KS
into western MO with trailing convection southward to along the
middle Red River Valley of northeast Texas, southeast Oklahoma and
southwest Arkansas. These areas will continue to see scattered
showers and a few embedded thunderstorms through the evening and
overnight hours as large scale ascent continues along the trough
axis with ejecting upper level low. Another shortwave trough on
the back side of the upper low is also noted across south central
KS and western OK, and this feature will shift farther southeast
overnight with additional convection possibly reaching our far
northern zones after midnight through early Wednesday morning.
Scattered convection will remain possible through the day on
Wednesday with this shortwave feature traversing the northern
third of our region. Elsewhere, expect hot and humid conditions
with high temperatures returning back to the mid 90s for highs on
Wednesday afternoon. Overnight temperatures will begin to increase
with lows in the mid to possibly upper 70s on Wednesday night as
warm, moist southerly flow from the Gulf prevails.
/19/
LONG TERM.../Thursday through Tuesday/
Closed upper level low pressure system over the central sections of
the country tonight will continue lifting to the Northeast toward
the Great Lakes Region as an open wave. The trailing trough axis
will keep rain chances for the more Northern parts of the forecast
area on Wednesday and the Eastern areas through Thursday. Another
disturbance aloft in the Northwest flow be approaching the Four
State Region Thursday night and by Friday providing scattered to
numerous showers and thunderstorms. Additional weak disturbances
will linger the rain chances for the area into the weekend with the
Northeast periphery having the higher rain chances. In the first
half of next week a significant upper trough will be moving into
the upper ridge out west carving out a deeply amplified trough
sending a cold front into the area by mid week with another round of
significant rainfall and cooler temperatures. Daytime high
temperatures will be warming well into the 90s in the rain free
regions with upper 80s to lower 90s in rain areas and thicker cloud
covered regions. /06/
&&
.PRELIMINARY POINT TEMPS/POPS...
SHV 75 96 76 97 / 0 10 10 20
MLU 74 97 75 97 / 0 10 10 30
DEQ 72 91 74 93 / 20 30 30 30
TXK 74 93 76 94 / 20 20 20 20
ELD 74 95 76 95 / 10 10 20 30
TYR 75 94 77 96 / 10 10 10 10
GGG 75 95 76 96 / 10 10 10 10
LFK 74 95 75 96 / 0 10 10 10
&&
.SHV WATCHES/WARNINGS/ADVISORIES...
AR...None.
LA...None.
OK...None.
TX...None.
&&
$$
09/13