Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 08/23/18
Area Forecast Discussion
National Weather Service Binghamton NY
1033 PM EDT Wed Aug 22 2018
.SYNOPSIS...
High pressure will move into the region tomorrow and bring dry
weather and plenty of sunshine through the end of the week. As
the high moves east of the area, southerly winds will bring
humidity and a chance for showers back to the region.
&&
.NEAR TERM /THROUGH THURSDAY/...
With the late evening update, rain chances were updated based
on radar trends and that the HRRR and RAP both linger some pesky
showers into the overnight. Cloud cover also looks to be
persistent into the overnight. However, high pressure will
begin to build in allowing for generally clearing skies. Left
out mention of fog overnight as the transition to high pressure
will keep winds up enough to help mixing. Although a few deep
valleys may see fog for a slight time before sunrise. Low
temperatures should be in the 50`s.
&&
.SHORT TERM /THURSDAY NIGHT THROUGH FRIDAY NIGHT/...
A quiet weather pattern is in store for the region as ridging
both surface and aloft will build over CNY/NEPA This will bring
generally clear to partly cloudy skies.
Humidity levels also look comfortably low, given the Canadian
origin (which was previously Alaskan...and then previously
Siberian) of the incoming air mass.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
Warm front will approach later in the day on Saturday, moving
through Saturday night, bringing a chance of showers and slight
chance t`storms. Most of the day Saturday is looking dry at this
time, with highs in the upper 70s to lower 80s. With the weak
upper trough moving through on Sunday, and much higher level of
instability, could see some scattered late day t`storms around.
Otherwise, it`ll be partly sunny and warmer with highs in the
lower to mid-80s. Lows in the upper 50s to mid-60s over the
weekend.
The forecast area remains on the northern periphery of a strong
upper level ridge Monday through Wednesday. Weak shortwaves and
MCS type convection will likely ripple through the westerly
flow pattern impacting our forecast area at times...especially
our NY zones. The source region of moisture looks to be more
from the central Plains region this time around. Therefore,
heavy, torrential, tropical-like downpours are looking less
likely during this time period. Gusty t`storm winds may be more
of an issue. These details will of course be worked out as we
move forward in time.
&&
.AVIATION /03Z THURSDAY THROUGH MONDAY/...
Mainly SHRA affecting the area with only a few lightning
strikes reported. Pockets of +SHRA are moving through and will
continue to do so through the evening.
Conditions forecast to go VFR in all locations later this
evening as high pressure builds into the region. Northwest flow
will keep widespread fog limited overnight.
Good VFR will be the story on Thursday as high pressure
continues to move over the region. Winds will gust to 25 kts at
times as the atmosphere becomes mixed by afternoon.
Outlook...
Friday through Sunday...Mainly VFR. Early morning fog possible,
especially KELM.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...None.
NY...None.
&&
$$
SYNOPSIS... WFO CTP/ MWG
NEAR TERM... WFO CTP/MWG
SHORT TERM... WFO CTP
LONG TERM... WFO CTP
AVIATION... WFO CTP
Area Forecast Discussion
National Weather Service Denver/Boulder CO
843 PM MDT Wed Aug 22 2018
.UPDATE...
Issued at 843 PM MDT Wed Aug 22 2018
Forecast is largely on track with isolated thunderstorms over the
Palmer Divide and a few more in the mountains. Satellite imagery
shows large scale lift and considerable convection occurring
along the approaching trough from the west, and with the right
entrance region of a 75 knot jet max, we expect those showers and
storms to continue and spread east across the mountains overnight.
Can`t rule out redevelopment of a few more storms across the
plains as well later tonight into early Thursday morning with this
weather disturbance. Otherwise, main change was to add areas of
smoke to the forecast tomorrow. Flow behind this trough goes
west/northwest, which will bring in a large plume of smoke evident
on visible satellite imagery earlier today across northern
California, northern Nevada, southern Oregon, and southern Idaho.
HRRR Smoke model also shows this same evolution so very hazy/smoky
skies expected again on Thursday. Airmass will dry considerably
with the developing westerly downslope breezes. Gusty winds
expected across the mountains by morning, and spreading east
across the plains through the day.
&&
.SHORT TERM...(This evening through Thursday)
Issued at 336 PM MDT Wed Aug 22 2018
The current low center is seen on GOES-16 satellite over Idaho.
This is projected to stay to the North of the state and just
brush the northern Colorado border. With the moisture levels
higher today and PW values over an inch, convection is expected
over the higher terrain of the mountains and Palmer Divide this
afternoon and into the early evening hours. The storms will be
isolated to scattered with the main impacts being moderate to
heavy rain, lightning, gusty winds and possibly some small hail.
Some storms could move off the higher terrain onto the adjacent
plains, but will not hold together for too long given more stable
conditions to the east. However, if storms are able to hold
together they could drop periods of moderate to heavy rain. Clouds
will scatter out overnight leaving a chance of patchy fog
development over the far eastern plains. Lows are expected to be
slightly warmer than days past with temperatures in the upper 50s
over the plains and 40s in the mountains.
For Thursday, the upper low and trailing trough will push
eastward leaving the state in predominantly westerly flow.
Increased winds at the base of the trough and being on the more
stable side of the jet will allow for downsloping Thursday.
Moisture is expected to drop slightly as the ridge flattens out,
but should still be high enough for isolated storms over the
mountains. With the influence of the downsloping and deepening lee
side low conditions should stay too stable on the plains to
support convection Thursday afternoon. Winds will increase across
the northern mountains and foothills with some gusting to 40 mph
by the afternoon. Temperatures will rebound quickly back into the
upper 80s on the plains and 70s in the mountains.
.LONG TERM...(Thursday night through Wednesday)
Issued at 336 PM MDT Wed Aug 22 2018
Initially, a weak upper ridge is forecast to pass over the state
Friday and Saturday bringing warmer temperatures and a
continuation of dry conditions on the plains. Temperatures on
the plains will make it back into the lower 90s. Moisture from
Arizona and Utah will move into the mountains producing scattered
afternoon shower activity. After Saturday, an upper trough
developing over the Pacific Northwest will turn the flow over
Colorado to southwesterly. Moist southwesterly flow aloft will
continue into next week. Mountain areas will continue to be the
main recipients of afternoon shower activity. Next Tuesday night
or Wednesday, models are showing a deeper trough moving into the
northern Rockies which will move across Colorado. An increase in
showers should be seen along with some cooler temperatures in the
mountains and onto the plains on Wednesday.
&&
.AVIATION...(For the 00Z TAFS through 00Z Thursday evening)
Issued at 843 PM MDT Wed Aug 22 2018
Isolated storm threat this evening is over, with only a 10%
chance or so that a storm redevelops in the Denver area TAF sites
overnight due to upper level weather disturbance. VFR conditions
will prevail. South/southwest winds around 10 knots tonight will
turn more westerly Thursday morning and increase to around
15G22kts for most of Thursday afternoon during peak heating and
mixing. We`ll see some smoke/haze come in by 15Z with limited
slant range visibility likely and possible ILS approaches. At this
time, surface visibility is expected to stay greater than 6SM.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
UPDATE...Barjenbruch
SHORT TERM...Bowen
LONG TERM...Dankers
AVIATION...Barjenbruch
Area Forecast Discussion...Updated
National Weather Service Billings MT
833 PM MDT Wed Aug 22 2018
.UPDATE...
Convection in the west so far this evening has been less than
expected. Although the strongest upward forcing is aimed right at
our BEartooth/Absaroka mountains, the lack of moisture available
is limiting coverage and strength of convection. The area where
moisture is better per precip water values (Powder River and
Southern Rosebud) is actually getting a bit more robust showers
and lightning. While isolated to scattered showers will probably
continue overnight in our west due to the proximity of the upper
low, we may eventual see an increasing coverage and strength of
convection in our east late tonight as upper low and forcing
track that way. That said, we still dont expect to see any real
strong or severe storms, mainly garden variety. The latest HRRR
cycles support this thinking. Thus, we have adjusted PoP`s
accordingly. Rest of forecast looks fine. BT
&&
.SHORT TERM...valid for Thu and Fri...
An upper low centered over Idaho is spreading clouds northeastward
into southern Montana and northern Wyoming this afternoon. Showers
and thunderstorms are occurring over Idaho, far southwest Montana,
and central and southern Wyoming. The upper low should move
eastward tonight, and as it does, it should bring better dynamics
over the area and help to generate showers and thunderstorms over
our area. Shower and storm activity should be isolated initially
and then increase to scattered by late this evening. Any
thunderstorms that develop late this afternoon and early this
evening would have enough instability available to produce some
gusty winds and small hail, but we are not expecting severe
weather at this time. Scattered showers and general thunderstorms
are possible overnight and then should end from west to east
during the day on Thursday as the upper low continues to move
eastward.
Shortwave ridging should build in late Thursday into Friday,
bringing a period of dry and warm weather. An upper-level
shortwave trough and associated surface cold front should then
cross the region from west to east Friday afternoon into the
evening. The upper trough and surface front should help to
generate scattered showers and thunderstorms across the region
late Friday afternoon and evening, with the greatest chance north
of Billings.
High temperatures should generally be in the 80s Thursday and
Friday, with Friday being a few degrees warmer than Thursday. RMS
.LONG TERM...valid for Sat...Sun...Mon...Tue...Wed...
Quasi-zonal flow over the region on Saturday will bring mainly
dry conditions. A digging upper trough over the Pac NW and
associated low then look to eject multiple waves of energy over
the area increasing shower and thunderstorm chances Sunday
through at least Tuesday as the trough and low gradually move
towards the Northern Rockies. Drier conditions look to return for
Wednesday as shortwave ridging builds over the region. While
there remains model uncertainty in the timing and placement of
the aforementioned waves and precipitation, an unsettled weather
pattern looks to dominate the long term.
High temperatures look to range from the 70s to 80s most days,
with the coolest day being Tuesday, with highs in the upper 60s to
lower 70s. Low temperatures look to range from the upper 40s to
50s most nights/mornings. STP
&&
.AVIATION...
Isolated to scattered thunderstorms are moving off the mountains
and foothills, affecting KLVM VC at this time, but expected to
spread to KBIL and KSHR. Additional ISOLD showers/thunder have
developed near K4BQ and will move toward KMLS VC if persist. MVFR
conditions are possible in the thunderstorms along with gusty
winds. Scattered showers and a few thunderstorms will move through
the entire area overnight with MVFR conditions possible. Expect
areas of mountain obscuration through tonight. AAG/STP
&&
.PRELIMINARY POINT TEMP/POPS...
Thu Fri Sat Sun Mon Tue Wed
-----------------------------------------------------------
BIL 057/083 056/087 053/080 055/084 054/075 050/071 051/079
33/T 01/U 31/U 11/U 12/T 32/T 20/U
LVM 049/081 048/083 044/081 048/080 047/072 045/070 044/076
52/T 02/T 31/U 11/U 24/T 43/T 20/U
HDN 055/084 054/089 051/081 054/087 053/078 050/071 049/081
33/T 00/U 31/U 11/U 23/T 32/T 20/U
MLS 059/081 055/087 054/080 056/086 056/079 052/071 050/080
36/T 00/U 51/U 11/U 22/T 42/T 21/U
4BQ 059/081 055/089 054/082 054/089 055/083 052/074 050/081
35/T 10/U 31/U 11/U 11/U 43/T 31/U
BHK 057/080 054/089 053/080 054/086 054/080 050/073 049/079
36/T 20/U 51/U 21/U 21/U 43/T 31/U
SHR 052/081 051/089 049/083 052/088 052/082 049/074 048/081
22/T 10/U 21/U 01/U 11/U 22/T 21/U
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...None.
WY...None.
&&
$$
weather.gov/billings
Area Forecast Discussion
National Weather Service Flagstaff AZ
852 PM MST Wed Aug 22 2018
.SYNOPSIS...Deep monsoon moisture will remain over northern
Arizona through Friday. This will result in good chances for
afternoon and evening thunderstorms each day. A downturn in
shower and thunderstorm activity is possible over the weekend and
especially early next week.
&&
.UPDATE...Rain and thunderstorm activity continues along and south
of I-40 this evening. The heaviest precipitation remains over
southern Yavapai and northern Gila counties where Flash Flood
Warnings remain in effect for a few areas. The Flash Flood Watch
was cancelled for northern portions of Coconino County as the
heaviest rain fell mostly in Yavapai County through the afternoon.
For the overnight hours, expect to see shower and thunderstorm
activity gradually weaken and end into the early morning hours
across areas south of I-40. A few additional areas could see
heavy rainfall over the next couple of hours as a few stronger
cells remain across northern Gila County moving slowly to the
northeast.
&&
.PREV DISCUSSION /238 PM MST/...Ample monsoon moisture remains in
place across northern Arizona today. A trough is moving through
the Great Basin to our north and providing a focus for more
organized thunderstorm activity across northwestern Arizona,
where a Flash Flood Watch remains in effect through this evening.
This area has seen 1-2" of rain in the last 24 hrs and the ground
is already saturated. Any additional heavy rainfall could cause
flooding. Other storms producing very heavy rain this afternoon
along the I-40 corridor including the Ash Fork area. Latest HRRR
suggests storms in this area could continue for several more
hours. Elsewhere, scattered to numerous showers and storms will
persist through the evening hours. Some of the high-resolution
model guidance suggests activity persisting into central Arizona
overnight and we have kept scattered activity in the forecast for
areas generally from Flagstaff southward overnight.
The steering flow shifts to west to east on Thursday as the high
pressure ridge flattens in response to the passing trough. Similar
atmospheric moisture and instability profiles are anticipated,
would should again lead to scattered/numerous thunderstorms. Some
of this hinges on what happens overnight tonight and perhaps
lingers into the morning hours.
An active monsoon thunderstorm pattern will continue through the
week. Forecast trends point toward decreasing coverage of storms
over the weekend as moisture thins out. This downward trend could
last into next week.
&&
.AVIATION...For the 06z package...Scattered showers and
thunderstorms will continue south of a line from KFLG to KSJN
through the early morning hours. Local IFR/MVRF conditions are
possible near heavier showers. Showers and thunderstorms will
develop again tomorrow after 18Z across northern Arizona. Aviation
discussion not updated for TAF amendments.
&&
.FIRE WEATHER...Thunderstorms remain throughout northern
Arizona Wednesday evening and through midnight. Ample monsoon
moisture will remain Thursday with a good chance of showers and
thunderstorms. Overnight activity is possible. Friday will see
scattered showers throughout northern Arizona.
Saturday through Monday...A drier air mass will slowly filter
southward from the UT/AZ border starting Saturday. The drier air
will lead to a downturn, but not dissipation, in shower and
thunderstorm activity for areas north and east of the Mogollon Rim
by Monday. The White Mountains region can still expect high chances
for showers and storms.
&&
.FGZ WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
PUBLIC...ET/MCT
AVIATION...ET
FIRE WEATHER...NL/JJ
For Northern Arizona weather information visit
weather.gov/flagstaff
Area Forecast Discussion
National Weather Service Wilmington NC
905 PM EDT Wed Aug 22 2018
.SYNOPSIS...
A few showers and thunderstorms may precede an approaching cold
front through tonight. The front will clear the coast early Thursday
morning and bring cooler and drier conditions to the area through
Friday. A warming trend is expected over the weekend, with
seasonable warmth and humidity Sunday through early next week.
Above normal temperatures are possible Tuesday and Wednesday.
&&
.NEAR TERM /THROUGH THURSDAY/...
As of 8 PM Wednesday...While the HRRR has been emphatic about
scattered convective development for multiple runs storms thus far
have been inhibited by mid/upper dry air. The dry air has limited
areal extent in addition to vertical growth. At any rate there will
be a chance of showers/thunderstorms until the front passes through
overnight. The front is currently located just NW of GSB-SOP line
and is pushing quickly toward the southeast. Thus with FROPA, less
humid conditions with cooler temperatures expected to spread in
during the early morning hours.
Previous discussion...A few very light and isolated showers have
developed well inland ahead of the surface front. Surface analysis
and satellite imagery indicate the front is close to a line from
Raleigh to Rockingham to Lancaster at 18Z. Surface- based
instability remains marginal west of I-95, so would be surprised to
see anything more than weak shower development there over the next
few hours. The potential for scattered showers and a few storms will
continue along and ahead of the front, which should push off the
coast by 06Z if not a little earlier. The airmass does become more
unstable east of I-95, so activity could become a little more
vigorous late this afternoon and early evening. A small portion of
the Cape Fear region east of an Elizabethtown to Whiteville to
Shallotte line remains in an area outlined by SPC for a marginal
risk of damaging wind gusts, if any storms do manage to get going.
High pressure will build in behind the front, with a wind shift
overnight followed by clearing skies Thursday. Highs on Thursday
are expected to top out in the mid 80s as dewpoints fall into a
60-65 degree range.
&&
.SHORT TERM /THURSDAY NIGHT THROUGH FRIDAY NIGHT/...
As of 230 PM Wednesday...High pressure centered across the Mid-
Atlantic states will bring relatively cool & dry air southward
across the Carolinas. Precipitable water values Thursday night
should fall to around an inch on the coast and 0.75" inland, while
850 mb temps slip to around +14C. Mainly clear skies and the best
radiational cooling we`ve seen in over a month should allow lows to
fall deep into the 60s inland, certainly the coolest we`ve seen
since July 10th, and June 5th-6th prior to that.
The high will move off the Mid-Atlantic coast during the day Friday,
but will maintain a NE-SW orientation as a weak inverted trough
develops over the Gulf Stream off the Georgia and South Carolina
coast. This should maintain low-level winds from the northeast, with
dry air draining southwestward into our area. Dewpoints away from
the coast should mix down into the upper 50s Friday. Even with
plenty of sunshine highs should only reach the mid 80s, with east-
facing beaches potentially only approaching 80 with a healthy
onshore wind all day.
The inverted trough will try to shift a little closer to the coast
Friday night, but I`m hopeful showers will remain off the coast
until midnight. I`ve painted in some slight chance PoPs for showers
(no thunder due to the subsidence inversion aloft) along the beaches
south of Cape Fear late Friday night. Lows shouldn`t be quite as
cool, with mid 60s expected inland and upper 60s to around 70 near
the coast.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
As of 230 PM Wednesday...H5 weakness will prevail across the
Carolinas between the subtropical ridge over TX-AL and other ridge
off the coast Sat and Sun. The subtropical ridge will build ENE to
over TN during Mon and TN/NC during Tue-Wed. In the meantime, a weak
area of shear aloft along with a coastal trough (the old front)
drifting back onshore during Saturday may be enough to spark widely
scattered showers and tstms. Otherwise, a more typical summertime
pattern will develop the first part of next week with mainly widely
scattered diurnally driven convection each afternoon and evening.
The aforementioned ridge could suppress convection some Tue-Wed time
frame. Temperatures will gradually warm around normal Sat-Sun, then
above normal Mon-Wed. MEX highs may be a touch too cool Tue-Wed.
Otherwise, no significant impacts are expected at this time.
&&
.AVIATION /01Z THURSDAY THROUGH MONDAY/...
As of 00Z...Cold front very evident on radar moving through Raleigh.
Interestingly, most of the convection seems to be post frontal. The
NAM increases the convection through the overnight hours. Look for
the front to move through LBT around 05Z, reaching the coast around
08Z. Did add some thunder, however confidence only moderate. Winds
will shift decisively to the north, post frontal. Thursday, a
beautiful day with unseasonably cooler and drier conditions with a
continued northerly wind.
Extended Outlook...Generally VFR conditions as a surface ridge
of high pressure extends across the interior Carolinas. Periods
of MVFR ceilings possible Friday and Saturday as a weak coastal
trough develops and moves inland. Showers may accompany this
feature.
&&
.MARINE...
NEAR TERM /THROUGH THURSDAY/...
As of 8 PM Wednesday...The current forecast is on track and only
minor changes made with the latest update. Area marine observations
indicate southwest flow prevailing ahead of a front slated to move
across the waters early Thursday morning. The flow is projected to
veer from the southwest to the west, and eventually northwest as the
boundary shifts through. Choppy seas will continue until the
southwest fetch abates late. In addition, widely scattered showers
and thunderstorms are possible until the front pushes offshore.
Previous discussion...Southwest flow will continue through the
evening between high pressure offshore and a cold front
approaching the coast. The front will move offshore after midnight
along with the associated shift to northerly winds. Significant seas
will remain in a 3-4 foot range with some five foot seas building
into the outer waters late this afternoon and evening ahead of the
front. Scattered showers and a few thunderstorms will be possible
this evening before frontal passage. Winds will shift to
north-northeast by 2-4 AM as high pressure builds over the waters
from the northwest. After a post-frontal surge to 15-20 knots, winds
are expected to fall off to 10 knots by Thursday afternoon.
SHORT TERM /THURSDAY NIGHT THROUGH FRIDAY NIGHT/...
As of 230 PM Wednesday...High pressure will move eastward across
the Mid-Atlantic states Thursday night, then offshore Friday. A
northeasterly wind direction should dominate through the period.
Models have been quite consistent over the past couple of days with
the strength of this wind, expected to peak Thursday night into
Friday morning at 15-20 kt. This should create a very choppy 3 foot
wind wave, with combined seas building to around 4 feet, perhaps
locally 5 feet in the Frying Pan Shoals vicinity. Winds should
begin to diminish Friday afternoon and particularly Friday night.
Although mainly dry weather is expected, Scattered showers could
begin developing across the Gulf Stream Thursday night, pushing
southwestward and perhaps impacting the outer portions of the
coastal waters at times. This will become more likely by Friday
night as steering winds above the surface veer more easterly and a
weak inverted trough approaches from the Gulf Stream off the
Georgia and South Carolina coast.
LONG TERM /SATURDAY THROUGH MONDAY/...
As of 230 PM Wednesday...Surface ridge axis across the western
Carolina with a weak trough just offshore will maintain
northeasterly flow at the onset Saturday. The trough will push
onshore and weaken during Saturday allowing weak onshore flow
to develop later in the day. Light southerly winds will prevail
Sunday and Monday with high pressure east of the waters. Seas
will be 3-4 across the outer waters early Saturday then subside
to around 2 ft by Saturday night. 2 footers will persist into
Sunday and Monday given the weak flow and lack of swells.
Widely scattered showers and tstms possible at times Sat-Mon.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...None.
NC...None.
MARINE...None.
&&
$$
NEAR TERM...CRM
SHORT TERM...TRA
LONG TERM...SRP
AVIATION...43
Area Forecast Discussion
National Weather Service Jacksonville FL
940 PM EDT Wed Aug 22 2018
.UPDATE...A swath of moisture ahead of a cold front and being
enhanced by an upper level short wave trough was producing
persistent bands of heavy showers with isolated thunder across
Ne Fl this eve. Due to loss of heating no strong storms are
expected although isolated rainfall amounts of over 2 inches
will be possible the next few hours. High-res HRRR showing
this activity gradually weakening and pushing Se as the cold
front moves across the area ushering In drier air and the upper
short wave lifts out.
&&
.AVIATION...A cold front pushing Se towards the terminals
will produce scattered storms mainly this eve with activity
ending after midnight. Have VCTS with ocnl TSRA and IFR at JAX
til 02Z. Have VCTS with ocnl TSRA and MVFR at VQQ til 03Z. Have
VCTS at CRG til 03Z. Currently have VCSH at GNV and SGJ til
02Z-03Z although SGJ may need an amendment for possible TSRA.
&&
.MARINE...SSW winds have increased to 15 knots offshore and
these winds expected to gradually decrease and become west to
northwest by later tonight as a cold front moves across the
waters. Isolated showers and storms will be moving mainly
offshore the Ne Fl waters and may produce strong and gusty
winds in addition to lightning.
Rip Currents: Moderate risk expected Thursday.
&&
.PRELIMINARY POINT TEMPS/POPS...
AMG 72 90 73 88 / 10 20 20 40
SSI 76 89 76 85 / 10 30 40 50
JAX 74 92 74 92 / 40 30 30 40
SGJ 74 89 74 87 / 40 20 40 40
GNV 73 92 73 91 / 30 30 30 40
OCF 73 93 73 91 / 30 30 30 50
&&
.JAX WATCHES/WARNINGS/ADVISORIES...
FL...None.
GA...None.
AM...None.
&&
$$
PP/ACS/KB
Area Forecast Discussion
National Weather Service Newport/Morehead City NC
916 PM EDT Wed Aug 22 2018
.SYNOPSIS...
A cold front over the middle of the state will move through
eastern NC tonight and off the coast early Thursday. High
pressure will build in from the north Thursday and Friday, and
by early next week will then extend into the region from the
western Atlantic.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
As of 915 PM Wed...Convection remains rather limited over the
region as front approaches the coast. HRRR shows some increase
in cvrg next few hrs near cst poss where convergence is enhanced
with remnants of sea breeze. Will cont lower chc pops inland
next cpl hrs with higher chc imd cst thru 06 to 07Z. Precip
still expected to be mainly offshore by daybreak.
Prev disc...Looking at another 12 hours of active weather
followed by a prolonged period of mostly benign weather
beginning Thursday. Continued deep cyclonic flow through this
evening with an advancing cold front. The mid level trough and
associated vorticity will move through the area this evening and
produce scattered showers and thunderstorms. Dewpoints in the
lower to mid 70s and highs around 90 have produced MUCAPE values
around 3000 J/kg. The moderate instability combined with 0-6 km
shear around 25 kt will contribute to potential storm
organization leading to a low end severe weather risk for
isolated damaging winds. Locally heavy rains will also occur in
the strongest storms. Rain threat will end after midnight from
west to east as the cold front moves off of the coast 4-5 AM.
Drier air will sweep into the area in the northerly flow behind
the front. Lows will range from the upper 60s coastal plain to
the lower 70s south coast and mid 70s Outer Banks.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH 6 PM THURSDAY/...
As of 345 PM Wed...Drier, cooler and less humid conditions are
expected Thursday as northerly flow prevails in the wake of the
cold front. High pressure will build into the area from the
north producing mostly sunny skies with highs in the lower 80s.
&&
.LONG TERM /THURSDAY NIGHT THROUGH WEDNESDAY/...
As of 345 PM Wed...Drier/cooler airmass will prevail across the
region Thursday night and Friday. Temperatures are then
forecast to moderate into the mid 80s over the weekend and upper
80s to around 90 early next week in response to a building
upper ridge resulting a more typical summer surface pressure
pattern with high pressure extending inland from the Western
Atlantic and a Piedmont trough. Precipitation chances are still
looking below normal through early next week with a mainly
diurnally driven pattern beginning over the weekend with
isolated sea breeze activity inland in the afternoons/early
evenings and very small overnight chances near the coast.
Thursday night and Friday...The coolest air of the summer season
arrives by Thu night with clear skies and light winds resulting
in lows well inland dropping into the upper 50s with low 60s
closer to the coast with comfortable mid to upper 60s beaches.
Continued dry Fri with highs in the low 80s.
Saturday through mid next week...A weak pressure gradient over
the weekend will promote local sea breeze circulations to
develop and move inland with an isolated shower or storm
possible. As the more traditional surface pattern redevelops
Sunday and early next week, PWATs gradually increase but with
little to no forcing aloft, precipitation chances will remain
very low. The main affect will be a return to summer heat and
humidity values.
&&
.AVIATION /01Z THURSDAY THROUGH MONDAY/...
Short Term /through Thursday/...
As of 615 PM Wed...VFR shld cont to dominate. Sct convection
along and ahead of front could lead to brief sub VFR and gusty
winds thru evening. Drier air will spread in behind front later
tonight ending convective threat. VFR cigs shld grad sct out
later tonight with mclr skies expected Thu as much drier air
moves in behind the cold front. WSW winds this evening ahead of
front will become N later tonight into Thu as front moves
offshore.
Long Term /Thu night through Mon/...
As of 345 PM Wed...VFR conditions will prevail through the TAF
period as high pressure influences the weather over the area and
limits the precipitation potential through early next week.
&&
.MARINE...
Short Term /through Thursday/...
As of 915 PM Wed...As front approaches cst stronger SW winds
beginning to shift E with highest winds outer central wtrs
currently. Will drop SCA Pamlico Sound and srn wtrs and keep a
few more hrs central wtrs.
Prev disc...Moderate SW flow will continue through this evening
ahead of the advancing cold front. Winds will continue 15-25
knots and gusty ahead of the front with 4-6 ft seas over the
outer central/southern waters, and 10-20 knots and 3-4 ft seas
elsewhere. Behind the front winds will shift to the North 15-20
kt late tonight and Thu with seas 3-5 ft expected.
Long Term /Thu night through Mon/...
As of 345 PM Wed...NE-E flow 10-15 kt is forecast Thu night
through Sat with 3-4 ft seas through Fri night subsiding to 2-3
ft Sat. L/V winds Sun 10 kt or less are expected to become S 10
kt or less Mon with seas around 2 ft both days.
&&
.MHX WATCHES/WARNINGS/ADVISORIES...
NC...None.
MARINE...Small Craft Advisory until 1 AM EDT Thursday for AMZ152-154-
156.
&&
$$
SYNOPSIS...JME/HSA
NEAR TERM...RF/JME
SHORT TERM...JME
LONG TERM...JME/BM
AVIATION...RF/BM
MARINE...RF/JME/BM
Area Forecast Discussion
National Weather Service San Francisco Bay Area
831 PM PDT Wed Aug 22 2018
.SYNOPSIS...Temperatures are forecast to remain near seasonal
averages, or cooler than average, through the rest of the week,
into the weekend, and well into next week. Widespread night and
morning low clouds will continue with only partial afternoon
clearing expected in coastal areas.
&&
.DISCUSSION...As of 8:30 PM PDT Wednesday...The marine layer
deepened to about 3000 feet today, deep enough to mix out for a
time and allow for earlier clearing. Earlier clearing today
resulted in modest warming across most of our region. Even so,
today`s high temperatures remained slightly below seasonal
averages, especially for inland areas.
Current satellite shows that low clouds are not as widespread this
evening compared to last evening at the same time. However, low
clouds are expected to become widespread overnight as the boundary
layer cools. Since the marine layer is expected to remain deep,
look for widespread low clouds to develop inland once again by
Thursday morning. Indications are that Thursday will be a day much
like today, with clouds clearing in most inland locations by
midday, and with partial afternoon clearing at the coast.
Temperatures will remain mild and generally slightly cooler than
normal.
Sea surface temperatures along our coast have been trending
warmer lately due to lack of significant upwelling. This has had
an impact on our weather by keeping overnight temperatures
elevated to some extent, especially near the coast and in the
coastal valleys. A forecast update was completed earlier this
evening to increase overnight lows tonight and Thursday night. The
update also included adjusting tomorrow`s highs to bring them
more in line with persistence.
A shortwave trough near the coast of British Columbia is forecast
to drop southeast and into the Pacific Northwest by late Thursday.
This trough is not forecast to deepen sufficiently into northern
California to have much impact on our weather. Thus, only minor
day to day changes are anticipated through Saturday.
A second, colder, trough is forecast to drop south out of British
Columbia and deepen across northern and central California late in
the weekend and into the first part of next week. This will likely
result in inland cooling early next week, with model guidance
forecasting inland temperatures to drop as much as 10 degrees
below normal by Monday. This trough may be cool enough to mix out
the marine layer which would mean more sun in coastal areas and
thus little or no cooling there.
The longer range models keep the longwave trough position anchored
across the West throughout next week, which should mean continued
mild temperatures inland through the end of August.
&&
.AVIATION...as of 4:50 PM PDT Wednesday...Stratus has cleared out
of the terminals as METARS are reporting CLR to FEW clouds. Satellite
image shows stratocumulus clouds forming over the SF Peninsula
and just north of SNS and MRY. These clouds are seen to be
expanding and will bring an early return of cigs to SFO and the
MRY Bay Area terminals. This morning`s run of the HRRR smoke model
shows vertically integrated smoke increasing across the entire
area starting tonight.
Vicinity of KSFO...MVFR cigs returning by 04Z. West winds to 15 kt
through 04Z.
SFO Bridge Approach...Similar to KSFO.
Monterey Bay Terminals...MVFR cigs after 01Z at MRY and 02Z at
SNS.
&&
.MARINE...as of 04:45 PM PDT Wednesday...Light winds will persist
over the coastal waters through tomorrow with locally breezy winds
possible near coastal gaps in the afternoon and evening. A broad
area of high pressure over the eastern Pacific interacting with a
strengthening trough over inland California will cause
northwesterly winds to increase, mainly over the northern outer
waters, starting Friday. Northwest swell will remain generally
light through the period along with a weak southerly swell.
&&
.MTR WATCHES/WARNINGS/ADVISORIES...
.Tngt...None.
$$
PUBLIC FORECAST: Dykema
AVIATION: W Pi
MARINE: AS
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Area Forecast Discussion
National Weather Service Pueblo CO
259 PM MDT Wed Aug 22 2018
.SHORT TERM...(This evening through Thursday)
Issued at 259 PM MDT Wed Aug 22 2018
Clouds have been slow to break across southeast CO with portions of
El Paso, Kiowa and Prowers counties staying under clouds well into
the afternoon. Limited surface heating has resulted in limited
instability for these areas...and a few showers that have moved off
the higher terrain of Teller county into the El Paso county have
diminished. With dew points in the 50s and lower 60s across the
plains and banked up into the southeast...where sufficient heating
does occur, models suggest MLCAPE values of 1000-2000 j/kg. Deep
layer shears are running 30-40 kts where surface winds are more
easterly...so locations along/north of the surface boundary will see
the best chance for strong to severe thunderstorms this afternoon
and evening. This will run along and east of I-25, and along and
south of highway 50. This is where HRRR seems to be converging on
the stronger convection through the evening hours. Large hail and
damaging winds will be the primary risks for these areas. Low level
jet cranks up tonight and this will lead to a cluster of
thunderstorms across southeast plains into the overnight which will
shift eastward into KS after midnight.
Thursday will be a drier day as the upper trof over the northern
U.S. Rockies moves eastward across WY into the Central Plains. This
shifts the surface flow more westerly and helps dry out surface dew
points. There will still be some lift along the tail end of that
feature as it shears out across northern CO during the
afternoon...so another round of thunderstorms will fire up across
the mountains which will move eastward into the adjacent plains.
With lower dew points across the area, storms will be weaker and
less widespread though gusty winds and lightning will be the primary
threats. -KT
.LONG TERM...(Thursday night through Wednesday)
Issued at 259 PM MDT Wed Aug 22 2018
Thursday night-Friday night...Northwest flow aloft moderates
Thursday night and becomes more westerly through Friday night, as a
passing upper trough across the Northern High Plains continues to
translate east of the area, and upper level ridging builds back
across the Great Basin and into the Rockies. Models remain in good
agreement of much drier and subsident air working into the region
Thursday night and Friday, with breezy west to northwest flow
helping to dry the lower levels of the atmosphere. With that said,
models indicating only isolated afternoon and evening showers
possible, with best coverage across the Southern Mountains. With the
drier air working into the region, overnight lows could be on the
cool side, with the potential for strong radiational cooling, with
highs expected to warm back to at and above seasonal levels in the
mid 80s to mid 90s across the lower elevations, and mainly in the
60s and 70s across the higher terrain.
Saturday-Wednesday...No big changes to current extended forecast, as
west to southwest flow aloft progged across the region for the
weekend and into early next week, as more energy translates across
the Pac Northwest and pushes the upper high pressure across the
Southern High Plains. This will open the door for more monsoonal
moisture to spread back across the Rockies, with the best available
moisture remaining along and west of the ContDvd. Models do indicate
a deeper upper trough digging across the Great Basin through the
middle of next week, though differ on it movement across the Rockies.
At any rate, will keep current isolated to scattered afternoon and
evening storms over and near the higher terrain through the period.
Temperatures look to remain at and above seasonal levels, with highs
in the mid 80s to mid 90s across the lower elevations, and mainly
in the 60s and 70s across the higher terrain.
&&
.AVIATION...(For the 00Z TAFS through 00Z Thursday evening)
Issued at 259 PM MDT Wed Aug 22 2018
VFR conditions expected at the terminals this afternoon with -TSRA
developing over the mountains and moving off into the adjacent
plains. These may produce brief MVFR conditions if they impact the
terminals due to lowered CIGS and restricted VIS. Thunderstorms
will pull east of the terminals by 01-02z. There may be another
window of VFR to MVFR cigs for both KCOS and KPUB from 05z to 10z.
Beyond 10z west to northwest winds should help erode the cloud deck
eastward with VFR conditions expected Thursday morning. -KT
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...KT
LONG TERM...MW
AVIATION...KT
Area Forecast Discussion
National Weather Service Topeka KS
940 PM CDT Wed Aug 22 2018
.UPDATE...
Issued at 940 PM CDT Wed Aug 22 2018
With storms struggling to materialize in western Kansas in
satellite/radar data, have trimmed back PoPs more in line with the
12Z HREF/00Z HRRR & RAP, bringing the band of precip into the
western CWA starting at 06Z and reaching Topeka by 10Z. These
showers should be fueled by increasing 900-800 mb theta-e
advection through the morning as shown by all of the deterministic
models--thus confidence in their development is still high attm.
MUCAPE values of 500 J/kg and minimal effective shear should
minimize thunderstorm coverage.
&&
.SHORT TERM...(This evening through Thursday)
Issued at 255 PM CDT Wed Aug 22 2018
Several minor perturbations were noted on water vapor imagery
rounding the upper ridge across the region. Isolated showers earlier
this morning have since dissipated while elevated showers and
isolated thunderstorms persist over southern Kansas. I left a slight
chance for showers to impact north central Kansas through early
evening, however confidence is low based on low level dry air
advecting southward into the area.
For tonight, low level upslope flow increases over the higher
terrain of western Kansas. A strong, 40 kt low level jet develops
overnight, increasing the likelihood of sustaining convection as it
migrates eastward into the CWA in the 06-12Z time frame. Mid level
instability is very limited despite bulk shear values in upwards of
30 kts. While I cannot rule out isolated, morning thunderstorms, the
overall severe risk is low through Thursday morning. With rainfall
probabilities being likely to definite, forecast rainfall amounts
close to 1 inch will be common throughout the area.
Focus for the forecast is on Thursday into the evening hours as the
strong upper trough lifts out into the northern plains. The
potential for severe storms still hinges on lingering morning
showers and how long they persist. Current short term guidance
indicates scattered showers through early afternoon with some
clearing occurring across portions of central and north central
Kansas. Meanwhile, sfc lee cyclogenesis occurs in advance of a west
to east oriented warm front near and just north of interstate 70 by
late afternoon. The latest GFS and ECMWF solutions are hinting at
convection forming near and just north of the boundary in northeast
Kansas by 00Z. The latest NAM and wrf solutions depict similar
scenarios but have the boundary centered closer to the I-70
corridor. A deterrent to the sfc based convection however in central
Kansas would be the increasing h85 temps and low level inversion
layer. Regardless, if storms are able to overcome the inversion
layer, ample instability and shear values in excess of 40 kts would
support supercells capable of large hail, damaging wind gusts, and
perhaps an isolated tornado given the low level helicity values
depicted in forecast hodographs. Overall, will continue to monitor
showers overnight to determine how the mesoscale details with play
out with late afternoon thunderstorms.
.LONG TERM...(Thursday night through Wednesday)
Issued at 255 PM CDT Wed Aug 22 2018
Scattered convection remains likely through the first half Thursday
night as the upper trough gradually moves into the Great Lakes
region Friday. A subsident airmass builds in behind a weakening
frontal boundary over the area while strong h85 winds advect +20C
temps into northeast Kansas Friday through the middle of next week.
Meanwhile mean flow aloft transitions towards the southwest, with
weak perturbations translating through bringing occasional slight
chances for precipitation Saturday night through Wednesday. Coverage
is focused towards north central areas during this time.
&&
.AVIATION...(For the 00Z TAFS through 00Z Thursday evening)
Issued at 650 PM CDT Wed Aug 22 2018
Ceilings gradually lower to MVFR and IFR levels from west to east
between 09 and 15Z tomorrow as a band of showers and isolated
thunderstorms move through. Ceilings should improve in the
afternoon as this band pushes out, but additional showers and
storms may redevelop Thursday afternoon and evening throughout NE
Kansas. Winds will veer from the east to the SSE by Thursday
morning at 5 to 10 kts with some higher gusts behind the departing
morning showers.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...Skow
SHORT TERM...Prieto
LONG TERM...Prieto
AVIATION...Skow