Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 09/14/23
Area Forecast Discussion
National Weather Service Binghamton NY
951 PM EDT Wed Sep 13 2023
.SYNOPSIS...
Spotty showers will be mainly confined to north of the New York
State Thruway late tonight and will diminish Thursday morning.
A much welcomed dry period develops the rest of Thursday with
high pressure keeping fair weather in place through at least
Saturday.
&&
.NEAR TERM /THROUGH THURSDAY NIGHT/...
935 PM Update...
Still seeing some very light, isolated showers this evening
around the Catskills, NE PA and even near the Finger Lakes that
will be diminishing over the next few hours. The HRRR is showing
the placement of this spotty activity the best, so leaned on
that in particular with this update in the near term. Spotty
lake-effect showers are still expected overnight north of the
NYS Thruway through the first part of tomorrow, but outside of
the NAM Nest, the CAMs are not very impressed with this
activity, so did lower PoPs slightly overnight, and this trend
will be monitored.
635 PM Update...
Made just some minor updates to the forecast at this time,
mainly some small PoP adjustments for isolated showers
currently in NE PA and the Catskills. Any showers in these areas
will diminish this evening and then the focus will turn to
spotty lake-effect showers north of the NYS Thruway later
tonight through the first part of tomorrow. See previous
discussion below.
300 PM Update...
Rain has exited the area as NW flow pushes a drier airmass into
the area. Afternoon temps are expected to top out in the low to
mid 70s thanks to scattered skies letting some sun through.
There will be a slight chance for a late afternoon isolated
showers across the Twin Tiers as a weak shortwave moves into the
area.
Tonight, colder air from Canada filters into the region and few
to scattered skies will allow temperatures to fall into the mid
to upper 40s across much of the area with low 50s in the
valleys. Valley fog is expected to develop during the early
morning hours. Lake effect showers are expected to develop
across areas north of the NY Thruway tonight as the cold air
works its way over Lake Ontario. These showers should last until
early afternoon before high pressure builds into the region
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
245 PM Update
Very quiet and pleasant early fall like weather expected through
most of this period. After some early morning patchy valley fog,
Friday will feature dry conditions and mostly sunny skies. It`s
possible some thin, high level cirrus clouds on the very edge of
Hurricane Lee arrive late in the afternoon over our eastern
zones. Otherwise, it starts off chilly in the morning, but
afternoon highs are mild in the mid-60s to lower 70...which is
about on target for mid September.
Generally quiet weather looks to persist over our area Friday
night into Saturday, under a weak upper level ridge and
associated surface high. At the same time Hurricane Lee is
forecast to merge with, and become captured by a departing upper
level trough. This may cause the storm to take on a more north
or even briefly north-northwest ward track. The latest NHC
track guidance shows the most likely track of this
tropical/extra tropical system to be east of Cape Cod, then
heading north toward the far eastern tip of Maine or New
Brunswick on Saturday into early Sunday. Most of the latest
deterministic and ensemble guidance appears to have wobbled
slightly east with the track. Stuck with the NBM/ensemble
guidance for this portion of the forecast here. This gives
little impact from Lee in our forecast area, beside from some
mid and high level clouds east of I-81 and breezy north winds
15-25 mph, with a few gusts around 30 mph in the Catskills and
Poconos. Otherwise, it should be a decent day Saturday, with
more sunshine west of I-81 and highs forecast to reach the
mid-60s to low 70s once again. There remains a small amount of
uncertain in the ultimate track of Lee, so be sure to continue
monitoring the latest forecast from our office and the National
Hurricane Center in the coming days.
More quiet weather for our area Saturday night, with clearing
skies and diminishing winds as the remnants of Lee exit off to
the north and east. Weak surface high builds over the region
under a 500 mb ridge. Did add in some patchy valley fog, with
seasonably cool overnight lows around 50.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
245 PM Update
Current model data is rather consistent showing dry weather
persisting for our area during the day on Sunday. We start off
with ridging aloft over the region in the morning, with mostly
sunny skies. Then, the next upper level trough begins to
approach late in the day from the central Great Lakes
region.This should bring some increase in cloud cover late,
especially across the Finger lakes and Central Souther Tier
regions. Otherwise, it will be mild with highs in the low to
mid-70s and low humidity.
A fairly weak upper level trough, with limited moisture moves
through the area Sunday night and Monday. This will bring more
clouds and chances for scattered showers to the region. There
could be just enough instability with the cooler air aloft for
an isolated thunderstorm Monday afternoon as well. It will be a
touch cooler, with highs in the 60s to around 70 (except low 70s
Wyoming Valley). Perhaps some lingering lake effect clouds and
isolated showers for Tuesday, but overall it looks to be drying
out with temperatures very similar to Monday. By next Wednesday
guidance is warming our area up under mostly sunny skies as
upper level ridging advances east into the region.
&&
.AVIATION /02Z THURSDAY THROUGH MONDAY/...
740 pm update...
VFR should be the rule at most TAF sites into Thursday night.
Tonight some light lake effect rain showers will develop
southeast of Lake Ontario and continue into Thursday morning.
RME and SYR may dip briefly at times to MVFR. BGM/ITH will be on
the edge of the clouds but not have any showers.
ELM should be clear letting fog set up between 6 and 8z before
locking in at IFR and even VLIFR 8 to 13z.
AVP should stay too far to the south for the lake clouds.
Tonight winds will be light. Northwest a predominate direction.
Thursday winds increase to 10 kts with possibly some afternoon
gusts to 20 kts.
Outlook...
Thursday night through Sunday...VFR as a dry quiet pattern
dominates. At ELM, restrictions likely each early morning due
to valley fog.
Sunday night through Monday...restrictions possible in rain
showers.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...None.
NY...None.
&&
$$
SYNOPSIS...DK/JTC
NEAR TERM...DK
SHORT TERM...MJM
LONG TERM...MJM
AVIATION...TAC
Area Forecast Discussion
National Weather Service Boston/Norton MA
1011 PM EDT Wed Sep 13 2023
.SYNOPSIS...
A frontal system brings another period of heavy rain and
embedded thunderstorms this afternoon and evening. Localized
flooding may again develop along with impacts to this
afternoon`s commute. Much drier and more seasonable weather
then arrives for Thursday into at least Friday, although
Hurricane Lee still could make a closer pass late this week or
next weekend. Increasing surf and rip currents are likely to
begin around Tuesday and continue into the weekend, although
there is low confidence in any other impacts. Refer to the
latest forecasts on Hurricane Lee from the National Hurricane
Center.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
10 PM Update...
Showers have diminished significantly at this hour with just a
few downpours draped across SE MA, more stratiform showers
across Essex county, and a few weak showers along the coast
front, currently located along the diagonal from Orange to
Springfield to Hartford. All in all, not expecting much by way
in additional impacts from any of these showers as we head
towards midnight. The cold front will stall out a bit near the
Cape Cod Canal, leaving the Cape and Islands in the wet sector
of things through the first half of the morning. Thus, it would
not be a surprise to see a resurgence in shower activity across
the Cape after 06Z.
Previous update..
Convection finally starting to lose its punch this evening. A
cold front was just entering into western MA and CT this
evening, and will take several more hours to move across
southern New England. Drier weather will try to arrive
overnight, but the wet ground will likely mean fog and stratus
develop late tonight. Minor tweaks to temperatures.
Expecting showers and thunderstorms to be mainly offshore by
midnight. This front may get hung up across the Cape and islands
late tonight. So maintained a risk for some lingering showers
there.
Previous Discussion...
Main concern this afternoon and evening remains the threat of
flooding. Latest runs of the HRRR and NationalBlend captured the
second round/line of showers and thunderstorms moving across
central southern New England. This should all move offshore
after sunset. Flood Watch continues for now. Will likely be able
to trim some of the zones on the western edge of the watch
later this evening. But want to be certain that rainfall is done
before doing so.
Otherwise, expecting a cold front to move offshore overnight.
This will usher in cooler and less humid air late tonight. Drier
conditions expected also. Slightly above normal low
temperatures.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH THURSDAY NIGHT/...
Cold front may still be lingering across far SE MA Thursday
morning, but still expecting most of the day to be dry across
southern New England. Drier weather continues into Thursday
night.
Near to slightly above normal temperatures Thursday and Thursday
night. Much less humid away from the immediate coast.
&&
.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
Highlights...
* We continue to monitor Hurricane Lee which is anticipated to
pass close enough to bring strong winds and heavy rain as
soon as Fri night into Sat.
* Increasing rip current risk and high surf continues into part
of next weekend on beaches with southern and southeast
exposures.
Main focus in the extended is on Hurricane Lee. Questions to
resolve at this point are how far west does does Lee bend back and
its forward motion.
Synoptically we`ve got a ridge axis building over the
central/eastern Great Lakes and a shortwave lifting
northeastward into eastern Canada on Fri. This allows the energy
associated with Lee to potentially jog W/NW late on Fri into
Sat, but how far is still the question.
As previously mentioned we are still most confident in marine
concerns. Lee will keep pushing a lot of energy toward our
southern/southeastern facing beaches. The result will be 20+ ft
seas across our outer waters, E of Cape Cod and SE of ACK, on
Saturday. For our near coastal waters will have 10-15 ft seas.
This will result in a high risk for rip currents on Sat and
elevated risk for rips on Sun as well.
Given there is still roughly 100 nm error in track at this
timeframe this will impact the impacts that are realized. At
this point most concerned with strong to damaging wind
speeds/gusts along with flooding. Given how wet we`ve been it
won`t take a lot of rainfall to result in flooding issues for
our region. Still consistent on the earliest arrival of tropical
storm force winds by late on Fri. For the latest on Lee please
see information provided by the National Hurricane Center.
Beyond Sat will be drier with cooler northwesterly flow on Sun.
Still will be a bit breezy across the region, but those gusts
will be diminishing as the pressure gradient relaxes. Another
trough lifts into our region for early next week bringing shots
for isolated to scattered rain showers.
&&
.AVIATION /02Z THURSDAY THROUGH MONDAY/...
Forecast Confidence Levels:
Low - less than 30 percent.
Moderate - 30 to 60 percent.
High - greater than 60 percent.
Tonight...
Second round of showers and thunderstorms crossing southern New
England ahead of a cold front. This front should move offshore
tonight. Becoming VFR and drier from W to E behind this front.
Mix of VFR/MVFR east of this front.
Thursday and Thursday Night...High Confidence
VFR, though some IFR could hang across the Cape and Islands
through 15Z. Breezy NW flow, gusts to 20 kt possible across the
high terrain.
KBOS TAF...Moderate confidence in TAF. Timing of the convection
is the biggest issue. Still some question on whether
thunderstorms actually make it to the terminal.
KBDL TAF...High confidence in TAF trends. Becoming VFR and
drier. Timing could be off by an hour or so.
Outlook /Friday through Monday/...
Saturday: Mainly VFR, with local MVFR possible. Strong winds
with gusts up to 60 kt. Chance SHRA.
Saturday Night: VFR. Strong winds with areas of gusts up to
45 kt. Slight chance SHRA.
Sunday through Sunday Night: VFR. Breezy.
Monday through Monday Night: VFR. Slight chance SHRA.
Tuesday: Slight chance SHRA.
&&
.MARINE...
Forecaster Confidence Levels:
Low - less than 30 percent.
Medium - 30 to 60 percent.
High - greater than 60 percent.
Overall high confidence.
Rip Current Statement is in effect for today due to the risk
for dangerous rip currents. High surf is likely for Thursday
onward into early in the weekend, though tropical headlines may
supersede high surf headlines.
Rough seas expected across the outermost coastal waters. Through
Thursday night. Winds diminish some and turn N to NW behind a
cold front tonight into Thursday. Increasing winds Thursday
night as Lee gets closer to the waters.
Outlook /Friday through Monday/...
Saturday: Moderate risk for storm force winds with gusts up to
60 kt. Rough seas up to 25 ft. Chance of rain showers. Local
visibility 1 to 3 nm.
Saturday Night: Moderate risk for gale force winds with gusts
up to 45 kt. Rough seas up to 16 ft. Slight chance of rain
showers.
Sunday: Low risk for Small Craft Advisory winds with gusts up
to 25 kt. Local rough seas.
Sunday Night: Winds less than 25 kt. Seas locally approaching
5 ft.
Monday: Winds less than 25 kt. Slight chance of rain showers.
Monday Night: Winds less than 25 kt. Seas locally approaching
5 ft. Slight chance of rain showers.
Tuesday: Winds less than 25 kt.
&&
.HYDROLOGY...
Already began the process of canceling the Flash Flood Watch,
starting with western MA and parts of northern CT. Will probably
be canceling the rest of this watch before its original
expiration time of Thursday morning. Want to be certain that
there is no longer a flooding threat before doing so.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...Flood Watch until 8 AM EDT Thursday for CTZ004.
MA...Tropical Storm Watch for MAZ007-015-016-018>024.
Flood Watch until 8 AM EDT Thursday for MAZ004>007-012>021-026.
RI...Tropical Storm Watch for RIZ005>008.
Flood Watch until 8 AM EDT Thursday for RIZ001>007.
MARINE...Tropical Storm Watch for ANZ230>237-250-251-254>256.
&&
$$
SYNOPSIS...Belk/BL
NEAR TERM...Belk/KS
SHORT TERM...Belk
LONG TERM...BL
AVIATION...Belk/BL
MARINE...Belk/BL
HYDROLOGY...
Area Forecast Discussion
National Weather Service Cheyenne WY
527 PM MDT Wed Sep 13 2023
.SHORT TERM...(This evening through Friday night)
Issued at 230 PM MDT Wed Sep 13 2023
Forecast concerns deal with timing/location of precipitation
tonight into Thursday.
Currently...Trough of low pressure resides along the Laramie Range
this afternoon. Off to the west...a cold front lays along a line
from central Montana...southwest to north central Nevada. Radar is
showing isolated thunderstorms west of the Laramie Range. Getting
a few lightning strikes out of the storms...but nothing really
worrisome.
Upstream cold front begin s to approach the area this evening and
is located near a line from Harrison to Guernsey to Muddy Gap line
at 06Z. Front then sweeps through Cheyenne and Scottsbluff by 12Z
and finally through the southern Panhandle by 15Z or so.
GFS...ECMWF...NAM and SREF are all in good agreement with
precipitation developing behind the front. Best chances for rain
look to be mid morning Thursday through Thursday mid evening.
HRRR suggesting moderate rain with anywhere from 0.5 to 1 inch of
QPF across central Albany...north Laramie Range into southern
Converse County.
Some question on when precipitation will end. GFS by far the
quickest with precip ending by 06Z Friday. ECMWF and SREF hold
onto precipitation a little longer along the I-80 Corridor from
Sidney to Laramie. Generally kept PoP chances going from what the
ECMWF/SREF are showing into 12Z Friday morning. ECMWF holds onto
PoPs even into 18Z Friday. SO we will need to monitor.
.LONG TERM...(Saturday through Wednesday)
Issued at 230 PM MDT Wed Sep 13 2023
Warm and dry conditions expected for the weekend into early next
week. Could see an isolated shower or storm over the high terrain
Monday with better precipitation chances beginning Tuesday ahead of
an incoming upper-level system. Temperatures will be warm throughout
the long term, with highs in the 70s and 80s for most of the CWA.
Upper-level ridging expected to remain throughout the weekend and
into early next week. An upper-level ridge is positioned over the
western CONUS on Saturday and progresses easterly throughout the
day. Northerly to northwesterly upper-level flow continues
throughout the day before turning more westerly by Sunday. Warm and
dry conditions expected throughout the weekend with the ridge firmly
in places. Highs range from the upper-60s to low 80s across the CWA
on Saturday and low-70s to mid-80s for Sunday. Overnight lows will
be cold in a few locations with overnight lows in the upper-30s to
low-50s across the region. Temperatures in southwest Albany County
and southeast Carbon County will drop below freezing Saturday and
Sunday night, resulting in a chance for widespread frost both nights.
By Monday, the upper-level ridge begins to break down, with more
westerly to southwesterly flow developing for Monday. An upper-level
shortwave moves over the western CONUS Monday ahead of a stronger
upper-level trough off the coast of the Pacific Northwest. Modest
500mb cyclonic vorticity advection is expected ahead of this
shortwave, providing some lift southeast Wyoming. Weak surface flow
across the Snowy and Sierra Madre ranges turns southerly to slightly
southwesterly ahead of the shortwave, providing weak upslope and a
slight chance for precipitation Monday afternoon. PW values are low,
around 0.30in, but cannot rule out an isolated shower or two
developing across the mountain ranges. Cold temperatures at the
peaks allow for the potential for light snow showers in the highest
elevations. High temperatures Monday range from the low-70s to mid-
80s across southeast Wyoming and western Nebraska.
Better precipitation chances begin Tuesday ahead of the strong,
upper-level trough moving into the Pacific Northwest. Several
vorticity maximums eject out ahead of the incoming trough and
provide widespread synoptic lift to the area. PW values increase to
around 0.60in as upper-level flow turns southwesterly on Tuesday.
Southwesterly surface flow allows for upslope flow to develop across
the high terrain of Carbon and Albany counties. Coupled with
synoptic lift from the vorticity maximums and increased PW values,
isolated to scattered showers and thunderstorms will develop across
the high terrain and spread northeasterly. A similar pattern is
expected for Wednesday as the upper-level trough continues to move
towards the region. With the closer proximity to the trough,
stronger vorticity advection, and increasing PW values,
precipitation will likely be more widespread on Wednesday with
western Nebraska receiving a better chance for showers and
thunderstorms. Temperatures will be cooler on Wednesday due to
increased precipitation and cloud cover ahead of the approaching
trough. After Wednesday, both the ECMWF and GFS suggest the trough
evolving into a cutoff low that spins over the western CONUS for a
few days. This system will need to continue to be monitored as it
evolves over the next several days.
&&
.AVIATION...(For the 00Z TAFS through 00Z Thursday evening)
Issued at 515 PM MDT Wed Sep 13 2023
Tricky aviation forecast for the next 24 hours, with a cold front
digging to the southeast across the CWA, bringing with it chances
for fog and low CIGS for the Nebraska Panhandle early tomorrow
morning and increased precipitation chances beginning in southeast
Wyoming and moving eastward throughout the day. HiRes model
guidance has been increasing confidence for IFR conditions for the
Nebraska Panhandle from 10z to 16z tomorrow, with the HREF
probabilities for ceilings below 1k feet around 50% for KAIA,
KBFF, and KSNY. Main uncertainty is with the forecast soundings
indicating a fairly dry boundary layer and a significant dewpoint
depression, which will hinder fog development. Nevertheless, with
such strong probabilities in the HREF, and the forecast soundings
seemingly under-forecasting the available precipitation, went
ahead and started trending both vis and ceilings towards IFR.
&&
.FIRE WEATHER...
Issued at 230 PM MDT Wed Sep 13 2023
Elevated fire weather conditions over the south Laramie Range this
afternoon with very low humidity. Could see a few areas reach the
critical 15 percent level...but winds are expected to stay below
critical levels. Expecting to see a cold front move into southeast
Wyoming and Nebraska Panhandle this evening and through the
southern Nebraska Panhandle Thursday morning. Along and behind
this front...looking at showers and thunderstorms to increase in
coverage...along with cooler temperatures and higher humidity.
Best chances for showers will be late Thursday morning through the
afternoon...before showers come to an end Friday morning. Warmer
and drier for the weekend.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...None.
NE...None.
&&
$$
SHORT TERM...GCC
LONG TERM...AM
AVIATION...MRD
FIRE WEATHER...GCC
Area Forecast Discussion...UPDATED
National Weather Service Gray ME
1153 PM EDT Wed Sep 13 2023
.SYNOPSIS...
A slow-moving front brings scattered showers and perhaps a
thunderstorms to the area today. Drier weather arrives for the
second half of the week while a significant long period
southeasterly swell builds into the Gulf of Maine. Increasing
northerly winds then begin on Friday and continue through
Saturday evening as what is now Hurricane Lee moves into the
Gulf of Maine. Depending on the track of this system, heavy
rainfall and storm surge are also possible. Quieter conditions
will then return late this weekend through early next week.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
Update...Cleared clouds out a little quicker than previous
forecast. In addition patches of fog are clearly visible now via
nighttime microphysics RGB product. I have included areas of fog
in some of the more radiation fog prone areas...beyond the
patchy fog for much of the rest of the forecast area.
Previous discussion...An upper level trough and a slow moving
cold front will combine to produce scattered showers and
possibly a few thunderstorms during the overnight hours. This
will be the focusing mechanism for the precipitation to continue
at least for the first portion of the night. Have kept the
Flood Watches up for southern New Hampshire as the latest HRRR
continues to show rain entering that location for several hours
this evening in an area of high PWat values. This location has
been targeted with locally heavy rainfall of recent.
Plenty of low level moisture will remain in place overnight with
no significant drying trend at least in the lower levels of the
atmosphere. Thus, fog will develop once again which is in good
agreement with the latest HREF solution.
Overnight lows will drop from the 50s north to the 60s in the
south. An upper level trough will continue to exit the region.
There may be sufficient instability for a brief shower over
central areas, however the vast majority of the time will be
dry.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH THURSDAY NIGHT/...
Morning fog will mix out on Thursday leading to increasing
sunshine during the day. Drier air will enter the region with at
least partly sunny locations over the region.
More patchy fog will develop Thursday night as high pressure
builds into the region. It will be cooler with highs on in the
40s north to the 50s south. Surface dew points will be lowered
as well.
&&
.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
Overview: Hurricane Lee will approach Northern New England from the
south on Friday before entering the Gulf of Maine by Saturday
afternoon. This system will bring dangerous conditions to the marine
waters. Strong northerly wind gusts are also likely, especially
along the coast. Locally heavy rainfall is also possible depending
on how close the system tracks to the coastline. This area of low
pressure will exit to the northeast by Sunday morning with high
pressure building in behind it, allowing for a return to tranquil
conditions.
Impacts: Hurricane Lee will bring life threatening conditions across
the marine waters with tropical storm force winds, large swells of
15-20 ft across the outer waters, dangerous rip currents, and beach
erosion. Minor to pockets of moderate coastal flooding due to around
2-3 ft of storm surge. Strong northerly winds are also likely along
the coast and potentially inland south of the mountains. This may
cause power outages, especially where the ground is saturated. In
addition, depending on the track of the system, locally heavy
rainfall is also possible which could cause some localized urban and
small stream flooding.
Forecast Details: Latest deterministic and ensemble based guidance
continues to show what is now Hurricane Lee moving northward before
it arrives southeast of Cape Cod by Friday evening. Following this,
an upper level shortwave trough will absorb the system and shift it
northwest towards Northern New England and Nova Scotia. During this
time period, it will be undergoing extra tropical transition, which
combined with an incoming jet will expand both the wind and rain
shields. The system will be weakening as it advances northward due
to increasing wind shear and cooler sea surface temperatures but it
will still likely be a strong end tropical storm by the time it
reaches our latitude. As a result, confidence remains high for life
threatening marine conditions over the waters with tropical storm
force northerly winds. There is some potential for locally higher
winds to near hurricane force across the eastern waters and
therefore in collaboration with the NHC and WFO Caribou, a hurricane
watch has been issued. A tropical storm watch has been issued for
the remaining coastal waters. Significant swells of 15-20 ft can be
expected across the outer waters with 6-8 ft across portions of the
bays. This will cause beach erosion and dangerous rip currents.
Latest guidance indicates the potential for 2-3 ft of storm surge
but thankfully astronomical tides are low and therefore only
expecting minor to pockets of moderate coastal flooding at this
time.
Along the coast strong northerly winds remain possible with gusts
between 40-60 mph, and therefore a tropical storm watch has been
issued for coastal ME and NH. Winds of this magnitude will have the
potential to produce power outages. There remains uncertainty in how
far inland the strong winds will extend but would still plan for
gusts up to around 40 mph. Higher winds can be expected across the
higher terrain. Locally heavy rainfall is also possible but
significant uncertainty remains in this and it will depend on the
eventual track of the system. Please continue to keep in mind though
that impacts will be felt potentially hundreds of miles away from
the actual center.
Low pressure will exit to the northeast Saturday night with tranquil
conditions returning Sunday, albeit breezy winds. High pressure
returns early next week.
&&
.AVIATION /04Z THURSDAY THROUGH MONDAY/...
Short Term...Areas of LIFR/IFR conditions are expected again
tonight with gradual improvement from west to east Thursday
morning. VFR prevails on Thursday with light westerly winds.
Some LIFR and IFR conditions will redevelop tonight in patchy
fog.
Long Term...Deteriorating flight conditions Friday night with
increasing N winds to 20-25 kts with gusts up to 40 kts possible
by early Saturday through Saturday evening, especially along the
coast. RA is also possible during this period with lower
ceilings. Winds relax Saturday night through Sun as low pressure
exits to the NE and high pressure builds in.
&&
.MARINE...
Short Term...A cold front gradually crosses the waters tonight
which will bring winds to the southwest, then west by
tomorrow, diminishing our marine fog. A long period swell
continues to build into the Gulf of Maine in the meantime,
building to as high as 4 to 6 feet over the outer waters Tuesday
night. Winds may gust as high as 25 kt.
Long Term...Tropical storm force winds likely across the waters
Friday night through Sat evening with hurricane force gusts
possible across the eastern waters. Seas of 15-20 ft across the
outer waters with 6-8 ft in portions of the bays. Tropical storm
and hurricane watches have been issued.
&&
.HYDROLOGY...
Much of the region has been worked over with rain recently,
most notably southern New Hampshire where the flood potential is
highest. Once the front pushes east fall-like air will be
ushered into the region with PWATs dropping to ~0.5". This break
in the humidity is well timed as it will knock down any
tropical moisture moving north with Lee for the weekend.
With the expectation that Lee will have a large rain shield
showers could reach Maine and possibly parts of NH Friday
Night/Saturday. The rain chances drop off rapidly as you move
west as the drier airmass dominates. Based on the latest NHC
track the heaviest rainfall will be near the coast and
easternmost counties. Where rain does fall, topsoil moisture
will support little infiltration and it would be routed to
streams that are already elevated. Small stream flooding is
possible, but the rainfall appears insufficient to cause
flooding on any of the mainstem rivers at this time.
&&
.TIDES/COASTAL FLOODING...
Northeasterly winds increase Friday night in response to
tropical system Lee moving north well off the Eastern Seaboard.
Storm surge values do increase and approach 3 feet, but not
until Saturday morning which does not coincide with high tide.
Nevertheless, some coastal flooding and splash-over will be
possible Friday night if the wind fields increase faster then
expected.
Seas will continue to build on Saturday, as winds back to the
northwest before high tide. Splash-over and some coastal
flooding possible during this second high tide cycle late in
the day Saturday.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...Tropical Storm Watch for MEZ022>028.
High Rip Current Risk from 6 AM EDT Thursday through Thursday
afternoon for MEZ023>028.
NH...Tropical Storm Watch for NHZ014.
High Rip Current Risk from 6 AM EDT Thursday through Thursday
afternoon for NHZ014.
MARINE...Hurricane Watch for ANZ150>152.
Tropical Storm Watch for ANZ153-154.
&&
$$
NEAR TERM...Legro
Area Forecast Discussion
National Weather Service North Platte NE
652 PM CDT Wed Sep 13 2023
...00Z AVIATION UPDATE...
.SYNOPSIS...
Issued at 334 PM CDT Wed Sep 13 2023
Key Messages:
- A cold front will move southeast on Thursday and provide a focus
for showers and thunderstorms. Chances for showers and a few
thunderstorms Thursday night into Friday.
- Dry and mild weather is expected this weekend as upper level
ridging builds into the region.
&&
.SHORT TERM...(This evening through Thursday night)
Issued at 334 PM CDT Wed Sep 13 2023
A shortwave trough will cross the Rockies tonight and reach the
Northern Plains. With a light southerly wind tonight, an increase in
moisture with lows to range in the low to mid 50s. There is the
potential for stratus and patchy fog to develop across southwest
Nebraska and the western Sandhills beginning late tonight into mid
morning Thursday. This is supported by the SREF ensemble as well as
the HRRR and RAP.
The positively tilted shortwave trough will move across the Dakotas
and into the Nebraska panhandle by late in the day. A southeastward
moving cold front will be well ahead of this upper trough and
should be located along a line from near Ainsworth to Ogallala by
22Z. Dewpoints in the upper 50s to near 60 will pool along and
ahead of the cold front. Mid-level lapse rates are only near 6C/KM
are poor overall...but the increase in surface moisture and
afternoon heating will support SBCAPEs along and just ahead of the
front hear 1000 J/KG. With poor mid-level lapse rates, and weak
shear to near 15- 20kts, no strong or severe storms area expected.
There could be some locally heavy downpours with individual
storms as PWATS increase to around 1.00-1.20" and a slow storm
motion to the southeast near 5kts. Some gusty winds are possible
however near any showers or storms.
Likely POPs are expected near the slowly advancing cold front
Thursday night, with chance POPs back behind the front, where mid
level frontogenesis will exist. Rainfall amounts have trended lower
across the area from less than a tenth of an inch to a quarter inch.
However, the latest CAMs still support those pockets of heavy
rainfall exceeding a half inch.
The precipitation will gradually diminish from northwest to
southeast overnight as the front and upper trough slowly moves
southeast.
.LONG TERM...(Friday through Wednesday)
Issued at 334 PM CDT Wed Sep 13 2023
On Friday, still a chance for showers and isolated thunderstorms
across the southern half of the area as the upper trough crosses the
area. A cooler day, with high from the low to mid 70s. Northerly
winds will be light only up to 10 mph.
The upper level trough will move across the Great Lakes and Midwest
on Saturday with an upper ridge building across the Rockies. The
ridging then begins to flatten out an become zonal into Tuesday of
next week then southwesterly aloft Wednesday as an upper trough
deepens across the Western U.S. Temperatures will be warming as we
head into the weekend, with highs returning to 80 to 85 by
Sunday. near normal by Sunday. Above normal temperatures are then
expected Monday and Tuesday. Moisture will begin to increase
Tuesday, with a return of precipitation chances Tuesday into
Wednesday.
&&
.AVIATION...(For the 00Z TAFS through 00Z Thursday evening)
Issued at 646 PM CDT Wed Sep 13 2023
Clear skies early in the period will give way to increasing
cloudiness during the overnight hours. Low-level stratus will move
in from the south with ceilings expected to drop below 3kft AGL.
Various guidance hints at ceilings falling to IFR criteria at LBF,
but confidence in this is too low at this time so will limit to
1kft or higher. Should the lower ceilings materialize, period of
greatest concern will be around sunrise. Expect improving
conditions during the day Thursday but a quick approaching frontal
boundary will bring a sharp wind shift at VTN and persistent mid-
level cloudiness. Though the potential for rain and thunderstorms
will increase towards the end of the period, will keep mention out
of this forecast given some timing and placement discrepancies.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...Roberg
SHORT TERM...Roberg
LONG TERM...Roberg
AVIATION...NMJ
Area Forecast Discussion...UPDATED
National Weather Service Lubbock TX
839 PM CDT Wed Sep 13 2023
...New UPDATE...
.UPDATE...
Issued at 839 PM CDT Wed Sep 13 2023
Quick update tonight to reflect recent observed trends and recent
hi-res models. Lone storm crawling S-SE across Bailey County
appears to be running out of steam as it encounters increasingly
hostile CIN and outruns a narrow N-S instability axis. This cell
may be able to survive a bit longer provided it can tap into a
skinny layer of elevated CAPE; however, overall forcing for the
next few hours is poor and the LLJ will be displaced too far
south tonight. Farther upstream in east/northeast NM, convective
trends are shaping up much better closer to a 700-500 mb impulse
that will track E-SE over our area later tonight. The HRRR is
performing well so far with this activity and given its acceptable
run-to-run continuity, have raised PoPs to 80% overnight centered
generally along the Highway 84 corridor coincident with a NW-SE
oriented moisture gradient from 850-700 mb. Severe prospects
remain low overall with locally heavy rain and some flooding the
bigger risk per WPC`s slight risk ERO. No other updates at this
time.
&&
.SHORT TERM...
(This evening through Thursday)
Issued at 231 PM CDT Wed Sep 13 2023
Westerly flow aloft will persist over the region with the upper
level trough over the Great Lakes region transiting to the northeast
and an area of high pressure over central Mexico. Scattered showers
are expected to continue this evening with the continuation of the
strong jet level flow, isentropic ascent, PWATS above 1.5", and
elevated instability in place. Southeast surface flow in combination
with the persistent robust cloud cover have kept the area cooler
than anticipated, therefore have lowered todays high temperatures by
a few degrees with CONSshort. Current satellite imagery shows a
deeper shortwave trough over the Four Corners region tracking to the
east which will help provide PVA over the FA resulting in increased
lift for more widespread convection overnight into early Thursday
morning. Additionally with better elevated instability with MUCAPE
above 500 J/kg and steepening lapse rates associated with the
approach of the shortwave trough axis, a few stronger storms capable
of strong wind gusts up to 50 mph are possible. The main concern
will instead be the potential for locally heavy rainfall with skinny
CAPE profiles and deep saturation supporting efficient rainfall.
Similar synoptic pattern as today for Thursday with persistent
mid- level isentropic lift expected to result in the continuation
of showers throughout the day. Also similar to today, patchy early
morning fog is possible for the western South Plains and the far
southwest TX Panhandle with minimal dewpoint depressions and very
light surface flow. Slightly stronger upslope surface flow across
the rest of the region will be slow to dissipate with the
continued moist air mass expected to keep cloud cover in place
at least through early afternoon. Therefore, we have sided with
the cooler guidance for highs tomorrow with temperatures in the
70s areawide.
&&
.LONG TERM...
(Thursday night through next Tuesday)
Issued at 231 PM CDT Wed Sep 13 2023
Showers and thunderstorms are likely again Thursday night and into
early Friday morning as moist isentropic ascent remains over the
forecast area. A shortwave trough will slowly move across the Four
Corners region on Friday before moving south through the Texas
Panhandle on Saturday. A moist atmospheric column along with
increasing large scale lift will lead to another round of showers
and thunderstorms on Friday and Saturday. Forecast instability and
wind shear parameters appear sufficient for a few strong storms
Friday afternoon and evening near the TX/NM border where forecast
CAPE is highest. Additional thunderstorms may move into the
forecast area on Saturday night along a cold front possibly
reinforced by storm outflow. Looks like we will have a break from
rain chances on Sunday afternoon through Monday morning but model
guidance indicates a weak shortwave trough moving through on
Monday may help initiate some thunderstorms near the TX/NM border
in the afternoon and evening. Precipitation and overcast skies
will keep temperatures in the 70s and low 80s through Sunday
before an upper level ridge builds over the area on Monday and
temperatures increase into the mid-80s and possibly the low-90s
early next week. Luckily, this ridging will be brief and we will
return to quasi-zonal flow by the middle of the week.
&&
.AVIATION...
(00Z TAFS)
Issued at 629 PM CDT Wed Sep 13 2023
MVFR ceilings currently at LBB and PVW may temporarily break out
to VFR in the next few hours, but this will be short lived as
increasing moisture pushes these to IFR after midnight and
eventually expanding to CDS thereafter. Some light fog is also
expected before this low cloud deck rises to MVFR by the
afternoon.
Barring a few -SHRA this evening, concern will be for at least
one round of TS arriving from NM overnight. Current TS near CVS
should struggle as the reach cooler/stable air, but another round
farther NW will have better forcing available overnight and is
likely to deal some impacts to LBB and PVW, anytime from 06z-11z.
&&
.LUB WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SHORT TERM...93
LONG TERM....17
AVIATION...93
Area Forecast Discussion
National Weather Service Newport/Morehead City NC
945 PM EDT Wed Sep 13 2023
.SYNOPSIS...
A cold front will cross the area late tonight with high pressure
building in behind the front late week through the weekend.
Powerful, long period swell from Hurricane Lee will build
through the rest of the week with the very large seas expected
to peak Thursday into Friday.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
As of 945 PM Wed...The surface cold front located over the
coastal plain has moved very little this evening. Ahead of it
the convection for the most part is beginning to wane with the
newer development now occurring over the southern coastal plain
and Sandhills region of eastern NC. Expect the showers and
storms to to continue gradually diminish and should end most
locations around midnight. The cold front is forecast to move
slowly east overnight and should be off of the coast around 12Z
Thu. The models are indicating a deeper and more persistent
plume of moisture remaining along the immediate coast overnight
into Thu bringing a very low chance of isolated coastal showers
overnight into Thu. As Hurricane Lee begins to track northward
well off the coast late tonight into Thu it will help to slowly
bring down a drier and cooler airmass into the Carolinas for
late this week into the weekend. Lows tonight inland will fall
into the mid 60s, but along the coast muggy low to mid 70s will
hang on for one more night.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH 6 PM THURSDAY/...
As of 345 PM Wed...High pressure will gradually build into the
area tomorrow behind the front, but moisture will continue to
linger through the better part of the afternoon and on-and-off
shower activity is likely to persist primarily over the Outer
Banks. The more notable weather tomorrow will be a steady
increase in north to northeasterly winds as the pressure
gradient tightens between the surface high and Hurricane Lee,
which will by this point be several hundred miles to our east-
southeast. The Outer Banks will see the most prominent increase,
with sustained winds of up to 30 mph and gusts near 40 mph
especially late Thursday afternoon. Inland areas will be
relatively breezier too, but only at about half the strength.
Dew points will continue to fall through the day, and by
nightfall readings in the upper 50s are likely across the inner
coastal plain. Highs will again be a few degrees cooler, topping
out in the low to mid 80s inland and around 80 along the coast.
The increase in northerly winds, combined with increasing swell
from Hurricane Lee, will continue to bring further
deteriorating coastal conditions in the form of coastal
flooding, beach erosion, dangerous shorebreak, and life
threatening rip currents. See the TIDES/COASTAL FLOOD section
for more details.
&&
.LONG TERM /THURSDAY NIGHT THROUGH WEDNESDAY/...
As of 400 AM Wed...Dry, cool, but windy conditions are expected
Thursday and into the weekend as strong high pressure building
in from the north tightens the pressure gradient with Hurricane
Lee passing by offshore. The combination of strong winds and
large swells from Lee will bring the potential for coastal
flooding across ENC beaches, more details on that can be found
in the Tides/Coastal Flooding section below. By late this
weekend high pressure will build to the south with conditions
moderating, and a cold front early next week will bring the next
chances for rain.
Thursday night through Saturday...Strong high pressure over the
Great Lakes will quickly build southward behind the front, and
the pressure gradient will begin to tighten as Hurricane Lee
moves northward through the western Atlantic. This will bring
strong northerly winds to the area, with the potential for Gale
Force winds across the coast and Outer Banks. Another byproduct
of this setup will be the introduction of a much drier and
cooler airmass to the Carolinas with Autumn-like conditions
expected into the weekend, with highs in the upper 70s to low
80s and lows dipping down into the 50s inland.
Despite passing well offshore, confidence is very high that Lee will
bring dangerous coastal conditions in the form of coastal flooding,
beach erosion, dangerous shorebreak, and life threatening rip
currents.
Sunday through Tuesday...High pressure will build to the south
Sunday, and moderating conditions are expected with high temps
bumping back up into the low to mid 80s. A weak cold front will then
swing through late Sunday and is expected to stall offshore for some
time early next week. Scattered showers and thunderstorms will be
possible from Sunday night onward, with best chances likely along
the coast and across the near shore coastal waters.
&&
.AVIATION /02Z THURSDAY THROUGH MONDAY/...
SHORT TERM /through Thursday/...
As of 650 PM Wed...Expecting primarily VFR conditions at the
TAF sites through the period. A cold front is forecast to move
east of the TAF sites after midnight allowing drier air to
filter into the region late tonight and Thu. This will end the
threat for additional showers/possible thunderstorms later this
evening. Overnight, there is some concern for the development of
low stratus behind the cold front. While most of the guidance
is backing away from this idea, the HRRR is indicating patchy
stratus developing 8-10Z and dissipating by 13Z Thu so will
handle this by forecasting a few/sct deck in the overnight
hours. Could also see some light fog as winds will likely
decouple for a few hours late tonight.
On Thursday, sky/vsby conditions rapidly improve but northerly
winds increase, with gusts up to 20 kt at times in the afternoon
for all terminals. Over the Outer Banks, gusts could be as high
as 35 kts.
LONG TERM /Thursday night through Monday/...
As of 400 AM Wed...Mostly VFR conditions are expected through
the weekend as cooler high pressure builds in. Gusty northerly
winds may bring some crosswind issues Thursday night and Friday.
&&
.MARINE...
SHORT TERM /Through Thursday/...
As of 945 PM Wed...Gale Warnings have been posted for all of
the coastal waters and the Pamlico Sound. SCA`s are in effect
for the remainder of the waters. The cold front will slowly
cross the waters late tonight and early Thu. Ahead of the front
widespread convection has temporarily disrupted the gradient
wind flow with variable winds 10 kt or less still occurring
across the waters this evening. Winds are forecast to become
N/NE late tonight and early Thu and increase rapidly on Thu due
to an increased pressure gradient between high pressure building
in behind the front and Hurricane Lee, which is progged to be
several hundred miles off the NC coast. Area wide winds will
average 20-30 kts sustained, with highest winds over Raleigh
Bay, Pamlico Sound, and the waters north of Cape Hatteras.
Forecast wind speeds are close to the previous forecast, but
higher winds cover a slightly larger area.
Long period seas (14-16 seconds) will continue to build through
Thursday as Hurricane Lee continues to lift north. By the end
of the period, seas are forecast to be up to 11-15 feet with
highest seas over the central waters.
LONG TERM /Thursday night through Sunday/...
As of 400 AM Wed...Powerful long period swell (14-16 second
periods) from Hurricane Lee will bring hazardous marine
conditions to the coastal waters through this weekend as it
recurves across the western Atlantic.
Winds will slowly subside Friday and become 15-25 kts by
evening. Winds will continue to decrease Saturday, and then
switch to the SW at 10-15 kts on Sunday. Seas will slowly
subside into the weekend, but remain hazardous.
&&
.TIDES/COASTAL FLOODING...
As of 355 PM Wed...Hurricane Lee will slowly progress northward
passing off the NC coast tomorrow and Friday producing strong,
long period southeasterly swell that will impact the entire
eastern seaboard. This longer period swell will continue to
build across ENC beaches over the next couple of days, peaking
tomorrow night into Friday. Very dangerous surf conditions with
large waves, strong rip currents, and powerful shorebreak will
persist into the weekend at all area beaches. High Surf Advisory
remains in effect for Hatteras and Ocracoke, the Northern OBX
and Core Banks, and the Crystal Coast beaches.
Additionally, the long period (14-18 seconds) will cause
extensive wave run-up, with the potential for significant beach
erosion, ocean overwash, and coastal flooding. In fact, during
last evening`s high tide that wave run up was already impacting
the dune line with minor over-topping at Mirlo Beach. Dune
erosion will continue with each successive high tide and may
become compromised at vulnerable locations in the coming days,
especially across Hatteras Island and Ocracoke. Greatest impacts
are expected late Thursday through Saturday morning when surge
guidance showing water levels reaching minor to moderate flood
category at the Duck gauge. A Coastal Flood Warning has been
issued for oceanside locations from Cape Lookout to Duck for up
to 2 to 4 feet of inundation above ground level. A Coastal Flood
Advisory was issued for the Crystal Coast, as well as locations
along the southern Pamlico Sound and Neuse River, for up to 1 to
2 feet of inundation above ground level.
&&
.MHX WATCHES/WARNINGS/ADVISORIES...
NC...Coastal Flood Advisory from 4 PM Thursday to 5 PM EDT Friday
for NCZ194.
High Surf Advisory until 6 PM EDT Friday for NCZ195-196-199.
Beach Hazards Statement from 8 AM EDT Thursday through
Thursday evening for NCZ195-196-199-203>205.
Coastal Flood Advisory from 4 PM Thursday to 8 PM EDT Friday
for NCZ195-199.
Coastal Flood Warning from 4 PM Thursday to noon EDT Saturday
for NCZ196-203>205.
High Surf Advisory until 8 PM EDT Saturday for NCZ203-205.
High Surf Advisory until 8 PM EDT Friday for NCZ204.
MARINE...Small Craft Advisory from 11 AM Thursday to 8 PM EDT Friday
for AMZ131-230-231.
Gale Warning from 5 PM Thursday to 11 AM EDT Friday for AMZ135.
Small Craft Advisory from 4 PM Thursday to 11 AM EDT Friday
for AMZ136.
Small Craft Advisory from 2 PM Thursday to 11 AM EDT Friday
for AMZ137.
Gale Warning from 5 PM Thursday to 2 PM EDT Friday for AMZ150-
152-154.
Gale Warning from 5 PM Thursday to 5 AM EDT Friday for AMZ156-
158.
&&
$$
SYNOPSIS...MHX
NEAR TERM...JME/MS
SHORT TERM...MS
LONG TERM...SGK
AVIATION...JME/CQD/SGK/MS
MARINE...JME/SGK/MS
TIDES/COASTAL FLOODING...MHX
Area Forecast Discussion
National Weather Service Tallahassee FL
757 PM EDT Wed Sep 13 2023
...New AVIATION...
.NEAR TERM...
(Through Thursday)
Issued at 219 PM EDT Wed Sep 13 2023
Across the upper levels, a rather strong jet streak for September is
extended across the southern conus from southern California towards
central Georgia. With the region predominantly remaining on the exit
region of the aforementioned jet streak, there will be some speed
convergence along the exit region of jet streak, which will aid in
forcing for ascent. This forcing for ascent coupled with the passage
of a backdoor front pushing southwest tomorrow will lead in
widespread shower and thunderstorm coverage across the region. PWATs
will also surge into the 2 inch range, which will lead to the
potential for heavy rainfall and localized flash flooding. With a
moderately strong jet streak just north of the region with 20-25
knots of 500mb westerly flow combined with a slow moving backdoor
front at the surface, and near 2 inch PWATs will lead to the
potential for back building convection and training storms. The
environment is primed on Thursday for the potential for localized
flash flooding across the region.
&&
.SHORT TERM...
(Thursday night through Friday night)
Issued at 219 PM EDT Wed Sep 13 2023
Zonal flow aloft will prevail through the end of the week aloft
while at the surface, high pressure will nose into the region from
the northeast. With a weak impulse moving through the zonal flow,
and plenty of deep layer moisture in place, scattered/widespread
showers and thunderstorms are forecast for Friday afternoon.
Additionally, a weak backdoor front moving in from the northeast
will provide an additional source of lift for showers and storms
through the day.
With the enhanced rain chances, and high pressure nosing in from
the northwest, a nice cool down is anticipated. This cooldown will
be most pronounced across our southwest Georgia counties where
high temperatures will likely only climb into the low 80s.
Temperatures in the upper 80s and around 90 across the Gulf Coast
are expected.
&&
.LONG TERM...
(Saturday through Tuesday)
Issued at 219 PM EDT Wed Sep 13 2023
Cooler and seasonable temperatures are expected through the
weekend and into early next week as broad troughing over the
southeast US continues. With broad ascent encouraged by the
trough, and deep layer moisture still in place, expect daily
chances for showers/storms at least through the weekend.
Rain chances will lower to become more isolated/scattered by the
start of next week as mid-level dry air attempts to move in from
the north and northeast. High temperatures will generally be in
the mid to upper 80s each after with overnight lows possibly
dropping into the upper 60s along the Gulf Coast for the first
time in a few months.
&&
.AVIATION...
(00Z TAFS)
Issued at 745 PM EDT Wed Sep 13 2023
Scattered showers and isolated thunderstorms continue across the
area but recent trends have shown a slow diminishing trend and
HRRR depicts this for the next few hours, ABY and VLD have VCTS
through 01Z then the TAFs have a period of VFR conditions
afterwards. Around dawn, especially in the areas that received
rainfall, a period of restricted flight conditions to LIFR/IFR is
possible from DHN-ABY-VLD 1-2 hours on either side of dawn.
Conditions should improve back to VFR after 14Z. Towards the
afternoon, diurnal scattered to locally numerous thunderstorms
will develop with all TAFs mention of VCTS beginning at 18Z. Brief
periods of MVFR/IFR can be expected underneath heavy convection.
&&
.MARINE...
Issued at 219 PM EDT Wed Sep 13 2023
A weak backdoor front will approach marine zones late this week
and into the weekend but it will likely stall across area waters
over the weekend. Winds will generally remain light at 10 knots or
below with seas less than 2 feet through the week. The only marine
concerns will be gusty winds near any showers/storms with the
greatest coverage of showers and storms likely being over the
weekend period.
&&
.FIRE WEATHER...
Issued at 219 PM EDT Wed Sep 13 2023
There are no fire weather concerns at this time; however, there will
be a 50-60% of showers and thunderstorms through the weekend across
most of the forecast area. With showers and thunderstorms, the main
concerns will be erratic/gusty winds and lightning across the
region.
&&
.HYDROLOGY...
Issued at 219 PM EDT Wed Sep 13 2023
Through Friday, we will need to look out for short-duration runoff
issues beneath the cores of heavy thunderstorms. The wind profile
on Thursday and Friday could even favor a few backbuilding
thunderstorms, creating the potential for localized pockets
getting a quick 3+ inches of rain.
Given the localized nature of heavy rain, river flooding is not
expected for the next 7 days.
&&
.SPOTTER INFORMATION STATEMENT...
Spotter activation is not requested. However, spotters are always
encouraged to safely report significant weather conditions when they
occur by calling the office or tweeting us @NWSTallahassee.
&&
.PRELIMINARY POINT TEMPS/POPS...
Tallahassee 72 92 72 87 / 10 60 20 60
Panama City 74 91 73 88 / 10 50 30 60
Dothan 70 89 70 84 / 10 50 10 50
Albany 70 89 70 83 / 30 60 20 40
Valdosta 71 89 70 84 / 30 60 20 50
Cross City 72 93 72 90 / 10 50 30 70
Apalachicola 75 89 75 86 / 10 40 40 60
&&
.TAE WATCHES/WARNINGS/ADVISORIES...
FL...None.
GA...None.
AL...None.
GM...None.
&&
$$
NEAR TERM...Bunker
SHORT TERM...Dobbs
LONG TERM....Dobbs
AVIATION...Scholl
MARINE...Dobbs
FIRE WEATHER...Bunker
HYDROLOGY...Haner
Area Forecast Discussion
National Weather Service Las Vegas NV
655 PM PDT Wed Sep 13 2023
.SYNOPSIS...Scattered showers and storms today across southern
Nevada and northwest Arizona. Activity expands into Inyo and San
Bernardino Counties tomorrow. Dry conditions return Friday and
persist into early next week as temperatures remain near normal.
&&
.UPDATE...Convection is starting to wind down across the area with
the loss of daytime surface heating. That being said, there are
still a few storms hanging in there and the passage of a shortwave
overnight might help sustain some activity in the southern Great
Basin tonight. Lacking instability and reduced moisture (current
PWATs are between .5 and .9 inches in that area) mean winds and
heavy rainfall should be less of a threat tonight compared to this
afternoon`s storms.
&&
.SHORT TERM...through Thursday.
Low-amplitude troughing persists over the western US today, leaving
our area under quasi-zonal flow ahead of an approaching shortwave.
Latest RAP shows very few (if any) vort maxima passing through this
afternoon, so convection is likely going to be terrain-driven.
Additionally, we`ll be in the left entrance region of a 250mb jet
streak, inducing subsidence and producing an inversion around 500mb.
However, temperatures above the inversion have cooled slightly,
resulting in CAPE values similar to what we saw yesterday, even
despite the slight decrease in moisture. 12z HREF mean shows 500-750
J/kg of SBCAPE this afternoon, primarily across Lincoln, Clark, and
Mohave Counties. This lines up well with modeled convection being
largely limited to southern NV and northwestern AZ this afternoon.
Dry low levels are expected to limit heavy rain potential, but up on
the high terrain where sub-cloud evaporation is mitigated, heavy
downpours will be possible. The HREF depicts this well, highlighting
the high terrain of Clark County and the AZ Strip with a 30% chance
of seeing 1" of rain. Gusty winds and lightning will be the main
concerns for the lower elevations. Later this evening and tonight,
another round of convection is possible across our northern areas as
the base of the aforementioned shortwave moves in. Given the limited
moisture and instability after sunset, impacts are expected to be
minimal at best.
Tomorrow, the shortwave moves through the area, sparking scattered
convection across much of the area, generally north of I-40. With
moisture continuing to decrease, so too will instability. Ensemble
mean SCAPE values are forecast to be less than 500 J/kg except for
Mohave County where they get up to 750 J/kg. In terms of potential
storm impacts, tomorrow looks fairly similar to today. Heavy rain
possible on the high terrain, gusty winds and lightning the main
concerns for the lower elevations. Temperatures both today and
tomorrow expected to remain slightly below normal.
.LONG TERM...Friday through Tuesday.
After the shortwave passes through on Thursday, drier air will begin
to filter into the region. As a result, PoPs drop below 10% for
pretty much the entire CWA and remain that way into early next week.
The only exceptions to this may be the Spring Mountains on Friday,
and the Sierra crest this weekend. As ridging develops over the
western US, temperatures creep up to slightly above-normal values
over the weekend. By next week, the ridge axis is forecast to shift
eastward, with troughing developing upstream. This will result in
decreasing temperatures and possibly increasing winds. How well the
northern and southern branches of the jet stream can phase will
determine how cool/windy we get.
&&
.AVIATION...For Harry Reid...Another day with mountain showers and
storms is expected from 18z through around 02z. Some of this
activity may drift off the higher terrain to the west and into the
Las Vegas Valley, but confidence is quite low. Still, gusty outflow
winds could affect KLAS in the late afternoon/early evening.
Otherwise light winds 10 knots or less are expected, first from the
northeast, turning slightly southeast after 20z. Winds to turn back
to the northeast tonight, becoming variable after 07z. Similar
conditions are expected again tomorrow.
For the rest of southern Nevada, northwest Arizona and southeast
California...Mountain showers and thunderstorms may bring impacts,
namely gusty outflow winds, to KVGT/KHND between 22z and 02z.
Otherwise generally light diurnal winds 10 to 15 knots or less can
be expected most terminals. The one exception will be KDAG, where a
few gusts to 20 knots can be expected late this afternoon into this
evening.
&&
.SPOTTER INFORMATION STATEMENT...Spotters are encouraged to report
any significant weather or impacts according to standard operating
procedures.
&&
$$
UPDATE...Meltzer
DISCUSSION...Woods
AVIATION...Austin
For more forecast information...see us on our webpage:
https://weather.gov/lasvegas or follow us on Facebook and Twitter