Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 08/06/24
Area Forecast Discussion
National Weather Service Boston/Norton MA
1042 PM EDT Mon Aug 5 2024
.SYNOPSIS...
Hot and humid conditions end today with a more comfortable
airmass settling in for the rest of the week. Showers expected
to form overnight and last into tomorrow morning. Another round
of moderate to heavy rain likely Tuesday night into Wednesday. Driest
period of the week occurs late Wednesday into Thursday. Impacts
from Debby will begin Friday and persist through Sunday.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
Update: 10:45pm
Thunderstorms across NY State continue to weaken this evening,
but we still expect a few showers, maybe a rumble of thunder to
move across parts of southern New England overnight. Interesting
00z CAMs show a spread in the guidance, even in the near term,
over the next couple of hours. Given the spread in the newer
guidance and the current forecast still aligns with radar trends
have not made any whole sale changes to the forecast over the
next several hours.
The HRRR and NAM performed pretty well in keeping convection to
our north this evening, so heavily relied on a combination of
those two hi-res models to derive the near term update. Do
anticipate that showers and isolated thunder will eventually
push into the region, between 06-10Z tonight. Mid level lapse
rates and MLCAPE deteriorate rapidly after sunset, so while bulk
shear remains supportive of organized cells and 0-1km helicity
increases over the next several hours, am not keen on a
continued severe threat into the overnight hours with shortwave
forcing diminishing.
Previous Update...
Up to 2500 J/kg of SBCAPE is available per SPC meso analysis, but
the atmosphere remains quite capped off in SNE. The best chance for
thunderstorms remain in southern VT and NH where the best forcing
from the shortwave is present.
Tonight:
Cold front drops south from northern New England tonight which should
bring a round of light to moderate rain showers starting late
tonight. Hi-res guidance is in fairly good agreement that shower
activity will move from west to east late overnight and last well
into tomorrow morning. There may be some residual elevated
instability overnight which could bring a rumble or two of thunder
overnight, but not expecting any severe weather after 8pm.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH TUESDAY NIGHT/...
Tomorrow:
Cold front looks to stall near the South Shore tomorrow which will
allow showers to continue into the late morning hours. Showers
possibly redevelop into thunderstorms over the Cape and Islands late
tomorrow morning into the afternoon where some elevated instability
will be present. Inland, drying conditions expected in the
afternoon, however, strato cumulus clouds likely hang around and
keep the skies mostly cloudy. Behind the front, winds turn NNE
allowing for cooler air from northern New England and the Gulf of
Maine to stream down. Highs look to top out in the low 70s near the
coasts, and upper 70s in CT River Valley. Dewpoints also fall to a
more comfortable levels into low 60s north of the Pike, to mid
60s along the South Coast
Tomorrow Night:
Still some uncertainty with how far south the cold front stalls.
Guidance seems to want to stall the front along or south of Long
Island stretching to Nantucket. A weak surface low looks to ride up
the stalled front overnight which will bring a widespread soaking
rain to much of the region. PWATS range from 1.0 north of the
MA Pike to 2.0 near the stalled front over the southern waters.
With strong forcing from a shortwave aloft and warm cloud depth
in excess of 10-12 kft, expecting moderate to heavy rain
showers. The best chance for seeing 1-2 inches of rain appears
to be across CT, RI, and SE MA. Further north, QPF totals will
likely fall off quickly ranging from 0.25-0.75 inches.
Overnight lows finally drop to a more comfortable level into the
low 60s and even some upper 50s.
&&
.LONG TERM /WEDNESDAY THROUGH MONDAY/...
* Potential for heavy rain to linger through Wednesday morning
associated with a stalled frontal boundary to our south
* Longest stretch of dry weather this week will occur Wednesday
evening through early Friday
* Impacts from Debby will begin late Friday, potentially lasting
through Sunday
Wednesday and Thursday...
There remains uncertainty in the location of a cold frontal boundary
come Wednesday morning, with the threat for the heaviest rain
occurring prior to 12Z. Still, cannot rule out some shower and
downpours persisting through the first half of the day. Shortwave
trough moves east of the region by Wednesday evening with weak mid
level ridging and surface high pressure building in for Thursday. Do
anticipate the period of Wednesday afternoon to late Thursday
evening will be the driest 36 hour period of the week. With frontal
boundary still south of the region, do anticipate much more
temperate highs for the mid week period, generally in the 70s with
much cooler dewpoints. Many locations will drop into the 50s
overnight Wednesday/Thursday, the coolest temperatures we have seen
in several weeks.
Friday through Sunday...
There appears to be some moderate consensus in that the impacts from
Debby will begin on Friday, and will likely persist through Sunday;
generally in the form of heavy rain and potential flash flooding.
The impacts felt here in southern New England will be highly
dependent on the exact track of the system, with a more coastal
track shifting the heaviest rain potential across our entire region
and a more inland track, like the GFS portrays, isolating the
heaviest rain threat to our western zones. It is much too early,
given mesoscale models have yet to include the period, to deduce the
exact location of heavy rain banding and rainfall totals, but will
note that ensemble probabilities continue to be quite notable for 24
hour QPF above 2" (up to 40% in the GEFS), and greater than 4" (up
to 20%) for portions of SNE, for the period of late Friday through
Saturday evening.
While ensemble probabilities are beginning to hint at a considerable
rainfall event for our region, there remains substantial spread
between ensemble members with the 10th and 90th percentile GEFS
painting very different scenarios; with as low as 2" (10th) and as
high as 6-7" (90th) of QPF through the next 7 days. 50th percentile
guidance settles around 3-4" for the region. So, while it is quite
possible that portions of our region see upwards of 5"+ of rain,
uncertainty remains too high to place much confidence in our QPF
forecast this far in advance. In collaboration with WPC and other
northeastern forecast offices, elected to keep the Day 5 ERO in the
Slight category, holding off on any upgrades to Moderate until
if/when confidence increases in our forecast.
In any case, do expect trough digging south across the Great Lakes
and eventually southern New England to sweep the remnants of Debby
to our east by late Sunday evening and Monday morning, setting up
for what looks like a much drier period next week.
&&
.AVIATION /03Z TUESDAY THROUGH SATURDAY/...
Forecast Confidence Levels:
Low - less than 30 percent.
Moderate - 30 to 60 percent.
High - greater than 60 percent.
Tonight...Moderate Confidence.
VFR becoming MVFR overnight, with IFR/LIFR over the Cape and
Islands. Winds stay out of the SE at 5-10 knots, gusting 20 knots
over the Cape and Islands. Light to moderate showers move from
west to east late overnight with showers starting around 09z and
lasting into Tuesday.
Tuesday...Moderate Confidence.
MVFR/IFR to start the day with light to moderate rain showers.
Showers eventually sink south in the Cape and Islands where some
residual instability could bring some thunderstorms, but
was not confident enough to include in TAFs at this time.
Guidance remains varied on the geographic extent of rain
tomorrow, but there remains a possibility that showers are
widespread from ~10Z to as late as 19Z before a lull develops
ahead of another round of rain Tuesday night.
Tuesday Night...Moderate Confidence
Another round of moderate to heavy rain is expected across much
of the region. There could be embedded thunderstorms overnight.
CIGS turn back to MVFR/IFR again.
KBOS TAF... Moderate confidence in TAF.
Low chance for a thunderstorm this evening mainly between
00z-04z. Rain chances increase again overnight with light to
moderate rain showers possible between 09z-15z, possibly even
lingering into 18z.
KBDL TAF... Moderate confidence in TAF.
VFR. Rain chances increase overnight with light to moderate
rain possible between 09z-16z.
Outlook /Wednesday through Saturday/...
Wednesday: Mainly VFR, with areas MVFR possible. Chance SHRA,
isolated TSRA.
Wednesday Night through Thursday: VFR. Slight chance SHRA.
Thursday Night: MVFR/IFR conditions possible. Chance SHRA,
isolated TSRA.
Friday: Mainly MVFR, with areas IFR possible. SHRA, isolated
TSRA.
Friday Night: Mainly MVFR, with areas IFR possible. Breezy.
SHRA, isolated TSRA.
Saturday: Mainly IFR, with areas MVFR possible. Breezy. SHRA
likely, isolated TSRA.
&&
.MARINE...
Forecaster Confidence Levels:
Low - less than 30 percent.
Medium - 30 to 60 percent.
High - greater than 60 percent.
Tonight through Tuesday night...Moderate Confidence.
Persistent southwest flow results in marginal small craft seas
across the southern outer-waters right into Tuesday. Showers and
possibly some thunderstorms move over the southern waters
Tuesday morning and linger into Tuesday afternoon. Widespread
moderate to heavy rain expected Tuesday night into Wednesday.
Outlook /Wednesday through Saturday/...
Wednesday: Winds less than 25 kt. Areas of seas approaching
5 ft. Rain showers likely, isolated thunderstorms.
Wednesday Night through Thursday: Winds less than 25 kt. Seas
locally approaching 5 ft. Chance of rain showers.
Thursday Night: Winds less than 25 kt. Areas of seas
approaching 5 ft. Chance of rain showers, isolated
thunderstorms. Local visibility 1 to 3 nm.
Friday: Winds less than 25 kt. Areas of seas approaching 5 ft.
Rain showers likely, isolated thunderstorms.
Friday Night: Winds less than 25 kt. Local rough seas. Rain
showers likely, isolated thunderstorms.
Saturday: Low risk for Small Craft Advisory winds with gusts up
to 25 kt. Areas of rough seas. Rain showers likely, isolated
thunderstorms. Areas of visibility 1 to 3 nm.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...None.
MA...None.
RI...None.
MARINE...Small Craft Advisory until 8 AM EDT Tuesday for ANZ254.
Small Craft Advisory until 8 PM EDT Tuesday for ANZ255-256.
&&
$$
SYNOPSIS...KP/KS
NEAR TERM...Dooley/KP/KS
SHORT TERM...KP
LONG TERM...KS
AVIATION...KP/KS
MARINE...KP/KS
Area Forecast Discussion
National Weather Service Billings MT
119 PM MDT Mon Aug 5 2024
.DISCUSSION...
Through Tuesday Night...
Last night`s shortwave scoured out the moist air mass in place,
and pwats are much lower today, but we are already seeing signs of
re-moistening. Satellite imagery shows monsoon moisture lifting
thru the northern great basin, where pwats are analyzed to be near
an inch, and in fact there is lightning in southern ID. A weak
shortwave combined with modest and very elevated (near 700-600mb)
instability should produce isolated showers & weak thunderstorms
beginning early this evening in our west and ending Tuesday
morning in the east.
Upstream there is a deepening trof over BC and this feature will
induce height falls in our region tomorrow. As this happens, pwats
will continue to increase, and ensembles show values back to 1+
inches by late afternoon. This is setting up our next round of
scattered thunderstorms, some of which may produce severe wind
gusts and locally heavy rain (and perhaps small hail...but wind is
the much greater severe risk w/ wet microbursts possible). Current
indications are for the 20-04z time period being favored for
severe wx tomorrow. Please stay alert if you have outdoor/travel
plans.
As the severe risk fades Tuesday evening, another shortwave
approaching from the west will combine with a Canadian cold
front/wind shift to keep a good chance of showers and embedded
thunderstorms going thru the night. Guidance is starting to hint
at the advection of low clouds from the north, aided by the onset
of upslope winds. Also, there are a number of active wildfires in
northern Canada, and we could see an increase in surface-based
smoke in the post-frontal air mass into Wednesday (high
uncertainty here).
Another item to watch is the area of stratus that is lingering
over our east, and slow to erode as it is associated w/ seasonably
strong high pressure over the Dakotas. Some component of low
clouds may linger tonight, and w/ some clearing there is a risk
of fog in our far east (Fallon & Carter) late tonight into early
Tuesday.
Regarding temperatures, it is looking like Tuesday will be the
hottest day of the week with temps into the low-mid 90s, ahead of
the Tuesday night cold front which will signal the start to a cool
second half of the week.
JKL
Wednesday through Monday...
Wednesday, an upper level low will begin to drop into the region
bringing precipitation chances and significantly cooler
temperatures. Most locations will have a 40-70% chance of
precipitation making it one of the best chances during the long
term. Temperatures will drop even further Thursday with most
locations having a 30-60% chance of having a high temperature
below 70F. The ECMWF EFI tables show -0.8 to -0.9 values
indicating anomalously low max temperatures. Temperatures will
hold steady Friday around 15 degrees below average in the low to
mid 70s.
Temperatures will start to rise over the weekend as upper level
ridging to our south starts to impact the region. Temperatures
will remain about 5 degrees below average however with
highs generally in the low 80s. Anomalously high dewpoints and
PWAT values will persist over long term with 850mb winds holding
onto a persistent easterly/southeasterly component advecting
plains moisture into the region. This will lead to daily
precipitation chances of 30-50% for Thurs, Fri, and Sat,
increasing to 40-70% for Sunday. The precipitation from these
showers and thunderstorms will add up with WPC showing greater
than 0.5 inches of precipitation across the region with some
locations seeing greater than 1 inch over the next week.
Those traveling into the high country Wed, Thur, Fri should
prepare for cooler temperatures and the potential for wet and
rainy conditions. Torgerson
&&
.AVIATION...
Broken stratus w/ MVFR-IFR ceilings continues to impact far
southeast MT (east of KMLS) this afternoon, and it is becoming
more probable that these low clouds will linger near the Dakotas
border into this evening and perhaps longer. If/when stratus
dissipates there is a reasonable opportunity for fog in this same
area late tonight, as recent HRRR runs are suggesting. This is
something to watch, but otherwise VFR will prevail thru midday
Tuesday.
Disturbance from the west will bring isolated showers and weak
thunderstorms tonight (exiting the east early Tuesday). Beginning
around 20z Tuesday, there is a greater chance (20-50%) of showers
and thunderstorms, some of which may produce strong wind gusts and
locally heavy rain. All TAF sites are at risk of seeing a TS
tomorrow afternoon & evening.
Lofted smoke will continue to reduce slant range visibility at
times.
JKL
&&
.PRELIMINARY POINT TEMP/POPS...
Tue Wed Thu Fri Sat Sun Mon
-----------------------------------------------------------
BIL 064/093 063/078 057/070 053/075 056/082 058/084 057/083
24/T 55/T 44/W 22/W 33/W 54/T 34/W
LVM 056/093 054/081 049/071 047/074 049/082 050/083 049/083
25/T 45/T 44/T 33/T 45/T 55/T 34/T
HDN 062/093 061/078 053/070 050/077 054/084 055/084 055/083
23/T 65/T 34/W 32/W 32/W 54/W 33/W
MLS 059/092 063/076 053/071 050/074 054/080 059/083 057/083
22/T 64/T 11/B 12/W 33/W 55/W 33/W
4BQ 062/094 063/079 056/070 053/074 054/081 059/084 057/083
22/T 64/T 24/T 33/T 33/T 54/T 43/T
BHK 054/088 059/077 049/070 046/074 049/079 055/083 054/083
12/T 63/T 11/B 12/W 23/W 44/W 43/W
SHR 059/095 059/077 051/068 048/076 050/083 053/084 051/083
23/T 45/T 67/T 54/T 33/T 45/T 35/T
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...None.
WY...None.
&&
$$
weather.gov/billings
Area Forecast Discussion
National Weather Service Columbia SC
914 PM EDT Mon Aug 5 2024
.SYNOPSIS...
Tropical Storm Debby will be moving slowly northward toward the
area tonight spreading across the state. Confidence is high for
potential heavy rainfall and flooding over the next several
days. Drier air should finally move into the region by the
weekend leading to lowering rain chances.
&&
.NEAR TERM /UNTIL 8 AM TUESDAY MORNING/...
Key Message(s):
- Rain and potential for flooding remains the highest concern
- Flood Watch now in effect for portions of the SC Midlands and CSRA.
- Highest rainfall through tonight over the southern/eastern
Midlands CSRA.
At 8 PM EDT, Tropical Storm Debby was about 50 miles WNW of
Jacksonville, FL with max sustained winds of 45 mph, moving toward
the NE at 6 mph. The slow northeastward movement is expected to
continue overnight, with the storm center reaching far southeastern
GA by Tuesday morning.
The outer rain bands of Debby are spreading across the area from
south to north this evening. Rainfall intensity right now is on the
lighter side, but heavier convective bands are not far to the south,
along with cooling cloud tops and increasing lightning activity
off the southeast coast of SC near Charleston and Savannah. The
heaviest rainfall potential tonight still appears to be in
areas south and east of I-20. A Flood Watch for Flash Flooding
remains in effect through Thursday evening to account for the
expected heavy rainfall. It should be noted that it is difficult
to pin down exactly where the heaviest rainfall could occur,
because even minor shifts in the track of Debby will change the
locations which receive the heaviest rain bands. That said,
parts of the area, especially south of I-20, could be looking at
1-2" of rainfall through the overnight period.
Outside of the rainfall threat, there is also a small threat of
gusty winds and saturated soils combining to bring some trees
down across the region. Sustained and winds gusts through
tonight will gradually increase, however gusts into Tuesday
morning are expected to reach a maximum of 25 mph in the CSRA and
southeastern Midlands, around 20 mph in the Columbia and Lexington
areas and slightly less in the western Midlands and Pee Dee.
With overcast skies now over the area and temperatures in the
upper 70s, only slight cooling is expected and low temperatures
will fall into the low to mid 70s.
&&
.SHORT TERM /8 AM TUESDAY MORNING THROUGH THURSDAY NIGHT/...
Key Message(s):
- Potential for life threatening flash flooding in the short term
- Portions of the area are in a rare High Risk for excessive rainfall
- A Flood Watch is in effect through Thursday evening
Debby will bring deep moisture into the forecast area for much
of the short term forecast. Guidance remains in agreement that
heavy rainfall is likely Tuesday through Thursday which will
pose a significant and life threatening flooding threat.
The rain shield from Debby is expected to push further north
early Tuesday morning spreading rain over most of the FA. As we
progress through the morning and into the afternoon we will see
bands of heavy rain with embedded thunderstorms pick up. These
bands of higher rain rates may be slow moving, potentially
leading to flash flooding especially south and east of I-20
where PWAT values will be around 2.5 to 2.75 inches. In this
area along and south/east of I-20 there`s potential for 3 to 6
inches of rainfall Tue and Tue night, with locally higher
amounts. These amounts in addition to very wet antecedent
conditions contribute to a high risk of excessive rainfall. The
banding of heavy rain and thunderstorms should lead to a tight
gradient in rainfall over the central FA. This somewhat hampers
confidence in flooding for areas north of I-20. Though a lesser
threat than the flash flooding, there may be a period on Tuesday
afternoon conducive to severe weather. Although the right-
front quadrant of the storm is expected to remain east of the
area there may be sufficient instability on Tue that
thunderstorms develop. Storm Relative Helicity values are high
enough to warrant a low threat of tornadoes in the extreme
eastern FA where 0-1 km EHI values from the RAP approach 1. This
may support brief, weak tornadoes in the eastern portion of SC.
There may be a brief reprieve from the heaviest rainfall on
Wednesday as Debby moves eastward. However, given the potential
for heavy rain on Tuesday it may not take as much rain to
produce flash flooding. Therefore it is still possible that the
eastern Midlands could see conditions stay the same or worsen
with lower rain rates.
Wednesday night and Thursday, Debby is forecast to lift
northward potentially bringing another round of heavy rain to
portions of the forecast area. This far out, confidence is
limited due to the exact positioning and intensity of the storm,
however there is potential for another round of heavy rain and
flash flooding on Thursday.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
Key Message(s):
- Improving conditions this weekend but river flooding is likely
Friday and into the weekend, the deepest moisture is forecast
to pull away from the forecast area. Clouds will likely clear
from west to east as drier air pushing in through the day on
Friday. Despite PWAT values lowering, atmospheric moisture may
still be high enough for showers or thunderstorms to develop.
Global ensemble means show moisture continuing to decrease into
the weekend leading to lowering rain chances. Temperatures in
the long term will be near normal.
&&
.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
Tropical Storm Debby remains well south of the area with
moisture associated with the system moving over the terminals.
Rain has moved into the Augusta and Orangeburg terminals and is
leading to some MVFR visibilities developing. In addition, MVFR
ceilings are expected to develop over the next few hours which
will then transition to IFR ceilings late tonight which will
likely continue through the day tomorrow. Rain will increase in
intensity overnight and into the day tomorrow, especially at
OGB. As a result, while periods of IFR visibilities in rain are
possible at all the terminals, the most likely IFR visibilities
will be at OGB. Winds will shift from easterly to northeasterly
with gusts around 25kts possible Tuesday.
EXTENDED AVIATION OUTLOOK...Low ceilings, reduced visibility and
rain, heavy at times, are expected to continue through at least
Thursday. Gusty winds may be possible through Wednesday night
as Debby moves through the region.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...Flood Watch through Thursday evening for SCZ022-027>031-035-
037-038-041-135>137.
GA...Flood Watch through Thursday evening for GAZ063>065-077.
&&
$$
Area Forecast Discussion
National Weather Service State College PA
1135 PM EDT Mon Aug 5 2024
.SYNOPSIS...
A dying cold front will move in from the north overnight and
stall out in southern PA Tuesday. This front may waggle north
and south some through the next few days, providing a focus for
heavy rain and strong thunderstorms. Hurricane Debby should
move slowly up the East Coast, diminishing to a depression and
then going extra- tropical as it does so. The heaviest rain
directly associated with the circulation should remain to the
south of PA until Friday or Saturday.
&&
.NEAR TERM /UNTIL 7 AM TUESDAY MORNING/...
Short wave trough moving across the nrn tier and wrn NY is
generating numerous SHRA with a few TSRA embedded clustered
over the Allegheny Plateau N of I-80. They are producing
0.25-0.50" rain as they pass, but just a spot or two has picked
up around 1". This is well below FFG thresholds. The showers
are being handled well by the recent HRRR runs, and confidence
is high that they will continue sliding eastward steadily over
the next 3-4hrs and exit to the east around 06Z. Have tapered
PoPs after the cluster passes, hanging onto a little tail of 20
pct trailing along to the SW of the cluster for another 1-3hrs.
But, much of the night will be dry as we`ll be in the short wave
ridge. Additional SHRA/TSRA may move in just after sunrise from
the NW. Latest surface analysis puts the cold front along the
long axis of LO at this time moving south. It should drop into
nrn PA late tonight. The dewpoints will stay high (m60s-l70s)
overnight and keep the muggies around. The cloud cover will vary
widely but much of the time could be described as partly cloudy
after the current SHRA move past. Fog will probably form across
the nrn tier where rain has fallen recently, but the varying
clouds may make it difficult to get dense. Will mention patchy
fog at this point N of I-80.
&&
.SHORT TERM /7 AM TUESDAY MORNING THROUGH WEDNESDAY/...
WPC did expand the MDT risk of ex rainfall slightly north-west.
Prev...
Main change for Tuesday is for slightly farther southward drift
of stalling frontal boundary. Latest model guidance halts the
weakening cold front over the South Central Mountains by 12z
Tuesday as upstream shortwave approaches from the Grt Lks.
Plenty of cloud cover, especially on the cool side of the front
over Northern PA, should hold temps down and limit the severe
weather threat Tuesday.
Given farther south settling of the stationary front, Tuesday
could be a relatively quieter day as far as stronger storms go,
although there will certainly be scattered shra and garden
variety tsra around, esp along and south of the front. Locally
heavy downpours are also possible, especially heading into
Tuesday night when the approaching wave and deep layer moisture
combine focused along the stationary boundary to bring a local
heavy rainfall threat Tuesday night into Wednesday in areas
that have been very wet just recently. 1 hr FFG values as low as
~1.4", 3-hr and 6-hr FFG values as low as 2.4" will be
challenged from Tuesday evening through Wednesday morning as
widespread 1-2"+ is expected from parts of the Lower Susq River
Valley eastward, with local amounts GT 4" possible. Will hold
off on watches for our area until we are within a 12-24 hour
window of expected impacts and heaviest rainfall.
The bulk of model guidance indicates the quasi-stationary front
will slip just southeast of PA Wednesday with decreasing showers
throughout Wednesday morning. A weak wave of low pressure
riding along this boundary will likely result in lingering cloud
cover and the chance of showers over the southern half of the
state. Can`t even rule out a tsra near the Mason Dixon Line,
where models show a bit of elevated CAPE. GEFS 2m temp anomalies
indicate max temps will likely be 5-10 degrees below average
Wed due to the cloud cover and easterly flow.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
Late evening update will hold minor changes for the days 4-7
time frame. So much uncertainty with the track/devolution of
Debby that making too wild of swings at this range unwise. We
have been messaging through many means that from Fri onward is
when we might see some heavy rain from direct influence of the
remnant low.
Prev...
Rather dry air works into the area by Wed, especially across the
north and west. This may support not much going on during the
first part of Thursday. The first part of Thursday thinking in
line with what I saw the last few days.
Main concern is moisture being advected back to the north and
west after early Thursday, with weak blocking high to the north.
Thus looking at a wet period after early Thursday into at least
the first part of the weekend.
Next chance of drier conditions early next week.
WPC working on rainfall outlooks for later in the week. Still
a lot of spread in the details at this range for late week.
&&
.AVIATION /04Z TUESDAY THROUGH SATURDAY/...
New round of showers moving west to east first part of the
night, mainly north airfields. Some fog and low clouds possible
overnight.
For Tuesday, looks like drier air works into the north and west
later in the day, main chance for storms would be across the
southwest later in the day at sites like JST.
Outlook...
Wed-Sat...Showers and storms expected at times. Impacts
expected.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SYNOPSIS...DeVoir/Dangelo
NEAR TERM...DeVoir/Dangelo
SHORT TERM...DeVoir/Fitzgerald
LONG TERM...Dangelo/Martin
AVIATION...Martin/Gartner
Area Forecast Discussion
National Weather Service Dodge City KS
654 PM CDT Mon Aug 5 2024
.KEY MESSAGES...
- Hottest day of the forecast period will be Wednesday as much
of southwest Kansas will heat to 100 to 105 degrees. A few 106
degree readings will be possible, especially across far
western Kansas.
- Significant pattern change toward cooler and wetter is still
on track beginning Thursday, August 8.
- Widespread 1-2" rainfall over the course of a roughly 5-day
period is increasingly likely in the August 8-14 time frame
(12Z ECMWF EPS 25-75th percentile for DDC of 0.60 to 2.25"
through August 15th).
&&
.DISCUSSION...
Issued at 323 PM CDT Mon Aug 5 2024
The mid-afternoon water vapor imagery and RAP analysis showed
the summer subtropical high extending from the Four Corners
region east across Oklahoma. A shortwave trough was moving east-
southeast across the Dakotas into Minnesota, which was
responsible for pushing a surface cold front south across the
Nebraska Sandhills into northeast Colorado. This front will
continue its slow, by steady push south this evening, reaching
the central portion of our forecast area during the pre-dawn
hours, around 09Z Tuesday or so.
This front will stall out just south of a Liberal to Pratt line
late Tuesday before dissolving and we start seeing post-frontal
upslope east-southeasterly winds develop. Along and south of the
front late in the day Tuesday, temperatures will still reach mid
to upper 90s, so these locations will not see a reprieve from
the 100 or near-100 degree heat. Mid level heights will remain
high (500mb heights around 597 decameters), which will result in
quite a bit of deep tropospheric subsidence such that no
thunderstorm activity is expected along the front across
southwest Kansas. None of the CAMs show a convective signal via
Composite Reflectivity across any of Southwest Kansas, so we
will keep POPs generally 10% or lower through Tuesday Night. Any
large convective system that develops across the higher terrain
of southern/southeastern Colorado is likely to remain out there
as it weakens through the evening/night given the absence of any
steering flow.
One more hot day is forecast Wednesday with much, if not the
entire forecast area sees southerly winds redevelop and 850mb
temperatures on the rise (+30C isotherm reaching U283 corridor
by 00Z Thursday). This will be the hottest day of the forecast
period, and this will be reflected in the official hourly
temperature and MaxT grids well into the lower 100s (around 105
from roughly Elkhart-Johnson northeastward to Scott City-
Dighton, continuing northeast up to Hays). Dewpoints will be low
enough to prevent Heat Index values from exceeding the actual
air temperature, and areas out west will be dry enough such that
the Heat Index will likely be at least a couple degrees lower.
Wednesday will be the last of the heat for awhile. A fairly
significant pattern change remains on track with confidence
continuing to grow in numerous days of fairly high precipitation
chances. Latest models and ensemble systems are starting to show
an even farther south push of the front, putting much of western
Kansas in favorable post-frontal moist upslope. The 100-member
Grand Ensemble of the NCEP GEFS, Canadian EPS, and ECMWF EPS all
point to a similar picture with each ensemble system showing
Mean Precipitable Water values in excess of 1.50" across pretty
much all of western Kansas starting late Thursday 8 August and
continuing through at least Tuesday 13 August. It is starting to
look like the pattern we saw back in June which brought a fair
portion of southwest Kansas much above average rainfall. Of
course, the devil is in the details with respect to individual
mesoscale convective systems within this pattern, but the
potential longevity of this pattern warrants a very good chance
for much of our southwest Kansas region to see well over an inch
of rainfall over a 3 to 5 day period coming up late this week
into early next week.
&&
.AVIATION /00Z TAFS THROUGH 00Z WEDNESDAY/...
Issued at 650 PM CDT Mon Aug 5 2024
Light south winds are forecast this evening at 10 kts or less.
A weak cold front will pass across the TAF sites between 12 and
14z, resulting in a windshift to the northeast at 10-13 kts. VFR
conditions will prevail even on the cool side of the front.
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
DISCUSSION...Umscheid
AVIATION...Finch
Area Forecast Discussion...UPDATED
National Weather Service Gray ME
1049 PM EDT Mon Aug 5 2024
.SYNOPSIS...
A cold front will cross the region tonight, bringing chances
for showers and thunderstorms, some of which could produce
locally heavy rainfall, damaging winds and large hail. A weak
area of low pressure will track off the southern New England
coastline on Tuesday and Wednesday, potentially bringing
scattered showers to southern Maine and New Hampshire while high
pressure allows for dry conditions for northern areas. Another
frontal system will bring scattered showers to the region late
in the week as tropical activity lingers near the East Coast.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
Update...Mostly minor changes to PoP as the front begins to push
its way south thru the forecast area over the next few hours.
Otherwise no significant changes to the forecast other than to
remove enhanced wording from thunderstorms.
Previous discussion...The first round of convection well ahead
of a cold front will continue to cross through the forecast area
the rest of this afternoon. For late this afternoon and this
evening, the latest HRRR continues to depict showers and
thunderstorms ahead of and associated with the passage of a cold
front. Despite surface dew points and PWATS lower today, some
of the storms still have the capability of producing very heavy
rainfall and flash flooding. As dynamics increase through this
evening, the threat for damaging winds will also increase. As
height falls begin, the possibility for large hail exists as
well as an isolated tornado.
Latest mesoscale models continues to indicate the precipitation
tapering off after midnight and shift off the coastline and into
the Gulf of Maine. Although drier air will be entering the
region, patchy fog will develop once again, especially in areas
that receive heavy rainfall.
Overnight lows will be much more comfortable than the last
several with readings in the 50s north to the 60s south. Winds
will be light but switch to the northwest.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH WEDNESDAY/...
Clouds will continue Tuesday and moreso Tuesday night as the
frontal system becomes stalled south of our forecast area.
Models suggest a weak wave may ride up the front Tuesday night
which will increase the chance for showers over southern areas
of Maine and New Hampshire. A few of these showers may be heavy
as there will be a sharp gradient in moisture from south to
north.
It will be much cooler during this period with slightly below
normal temperatures which has been a rare case this summer. We
then shift towards the long range portion of the forecast as
tropical moisture potentially moves towards northern New
England.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
-----------------------------------------------------------------
Summary:
*Generally cooler, more seasonable temperatures are expected during
the second half of this week.
*Remnants of TC Debbie could move into NH and ME towards the end
of the week, with flooding and heavy rain possible early on
this weekend. For more information, see `HYDROLOGY` section.
*Unsettled weather remains in the forecast after the passage of
Debby`s remnants.
------------------------------------------------------------------
Discussion:
A brief shortwave trough passes through the region on
Wednesday, bringing less humid and more seasonable temperatures into
the northeast. Zonal upper-level flow should allow these more
seasonable temperatures to last through the end of the week.
Otherwise, Wednesday and Thursday should be tranquil days with
partly cloudy skies.
A large plume of moist air from the south arrives on Friday,
bringing increasing clouds and humid conditions. A system associated
with the remnants of Debby may impact the region, bringing
notable rainfall this weekend. Despite the connection to a
tropical storm, we are not forecasting strong winds or other
tropical-related hazards. Flooding is the main concerning factor
with this weekend`s system.
For more details, please see the Hydrology Discussion near the
bottom of this AFD.
&&
.AVIATION /03Z TUESDAY THROUGH SATURDAY/...
Short Term...A cold front will bring another round of showers
and storms through the region for late afternoon and through
portions of the evening hours. Strong to severe storms are
possible, and TEMPO IFR (possibly LIFR) are likely for many
terminals. Most storms should push east of the area by 04Z
tonight, but there may be lingering showers across southern
areas through the night. Even though some drier air will be
working in behind the front, expect there to be some fog and low
stratus once again, especially in and around areas that receive
heavy rainfall. VFR expected Tuesday with a few showers
possible across, mainly south of a PWM-LEB line. Showers may
become more widespread with lowered ceilings Tuesday night,
especially over southern areas.
Long Term...
Some MVFR is possible at MHT and PSM Wednesday morning due to
scattered showers, otherwise sites should stay VFR through Friday
morning before restrictions lower as thunderstorms move into
northern New England.
&&
.MARINE...
Short Term...SCA conditions are not expected, but south to southwest
winds will become northwest behind a cold front. This front
will also bring increasing potential for strong to potentially
severe thunderstorms to push offshore this evening. A few
showers may linger a bit past midnight tonight, but then winds
will turn out of the northwest tonight into early Tuesday. Winds
the return to onshore Tuesday afternoon.
Long Term...
2-3 foot seas with light and variable winds less than 10kts expected
from Wednesday morning through early Friday morning. A storm system
moves in on Friday, with strengthening winds and seas from the east
expected during the day on Friday. Seas increase to 2-4 feet by the
end of the day Friday. Seas are expected to be elevated this weekend
and SCA issuance over the weekend is likely.
&&
.HYDROLOGY...
TONIGHT...
Scattered showers and thunderstorms later today will
generate locally heavy rainfall between 1-3, returning an
isolated risk for flash flooding. The airmass as a whole has
lost some moisture so rainfall rates would be 1-1.5/hr versus
the 2-3/hr from yesterday, however the repeat nature of some
storms could reintroduce some flash flooding. Areas of concern
continue to be those hit hard in recent days and where soil
absorption will be slower. Drier air will filter into the region
midweek allowing for a drying out period ahead of heavy rain
potential late week.
THIS WEEKEND...
WPC has expanded a slight risk for flash
flooding in the Day 5 ERO highlighting some tropical moisture
from Debby lifting into New England late week. A frontal
boundary north of the remnant storm will be a focus for heavy
rainfall over the northeast, regardless of the ultimate track of
Debby remnant circulation. However, the timing and location of
this frontal boundary has very low confidence. Precipitation
amounts are likewise very low confidence along with any specific
impacts. Nonetheless, a wet pattern is likely to set up Fri-Sat
with a ridge offshore and an approaching trough from Canada in
an airmass rich with tropical moisture increasing the risk for
flash flooding and will be monitored closely.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...None.
NH...None.
MARINE...None.
&&
$$
NEAR TERM...Legro
Area Forecast Discussion
National Weather Service Phoenix AZ
420 PM MST Mon Aug 5 2024
.Update...00Z Aviation Discussion
&&
.SYNOPSIS...
Excessive heat conditions will continue today across portions of the
area and through Tuesday for the Lower Colorado River Valley and
Southeast California. Thunderstorm chances today will mainly be
confined to the Arizona high terrain before spreading westward on
Tuesday. Shower and thunderstorm chances on Tuesday will become
fairly widespread across all of the Arizona lower deserts with
strong winds and blowing dust a good possibility. Rain chances
should persist over portions of the area on Wednesday before
retreating to mainly over higher terrain areas late week as
conditions begin to dry out. Temperatures should be closer to
seasonal normals during the middle of the week before heating back
up into next weekend.
&&
.DISCUSSION...
Mid-level water vapor imagery at this hour depicts somewhat drier
air pushing over the southeastern portion of AZ ahead of a well-
defined cyclonic circulation centered over Northern Mexico (south of
El Paso). This inverted trough south of El Paso will be the main
feature to bring us active weather during the middle of this week,
particularly tomorrow. Current RAP analysis shows abundant moisture
(PWATS >1.5") over South-Central AZ and MUCAPE between 750-1000
J/kg, but the environment should be well capped through tonight such
storms surviving/forming into the lower deserts is very unlikely.
This is also supported by the fact that we observed somewhat
widespread atmospheric overturning yesterday, and cloud cover
continued to linger overhead into early this afternoon. Showers and
thunderstorms should remain confined to the high terrain to the
north and east of Phoenix through this evening, with some stronger
storms in the southeastern corner of AZ and over the Northern Sonora
of Mexico. These stronger storms far to our south will help surge
moisture into the region overnight and set the stage for a potential
robust monsoon day on Tuesday. In anticipating a more active day
tomorrow, the SPC has outlined much of the Arizona lower deserts in
a marginal risk for severe thunderstorms due to wind and the WPC
also depicts a broad area south of Phoenix in a slight risk for
flash flooding.
As the four corners high remains in place with analyzed 500 mb
heights in excess of 596 dam, high temperatures will continue to
reach into the low 110s for the eastern deserts and near 115 for the
hotter locales of the western deserts. With more abundant moisture
than previously forecast and increased cloud cover, there is a
chance that NBM high temperatures will end up being too high for
this afternoon, but areas of Major HeatRisk persist nonetheless. As
such, a widespread Excessive Heat Warning continues through 8 PM
tonight. Areas along the Lower Colorado River Valley and in SE CA
will see mostly Moderate HeatRisk tomorrow, but heat indices will
still be in excess of 115 degrees thanks to the surge of moisture
expected overnight tonight, and so the Excessive Heat Warning for
those locations will be in effect through 8 PM MST/PDT tomorrow
evening.
.PREVIOUS DISCUSSION...
As the inverted trough moves through Sonora Mexico on Tuesday, the
northern fringes of the trough will extend into southern Arizona
providing decent forcing for thunderstorm development by the
afternoon hours. The added moisture from the overnight hours should
boost PWATs back into a 1.5-1.7" range, while lower level mixing
ratios improve to 11-12 g/kg. This improved lower and mid level
moisture along with daytime insolation should result in MUCAPEs of
1000-2000 J/kg. Easterly mid-level flow and 0-6km bulk shear of 20-
30 kts are also expected across south-central Arizona on Tuesday.
The added forcing from the inverted trough is expected to bring
higher terrain thunderstorm development during the afternoon hours,
especially across southeast Arizona. The combination of the
instability and the decent winds aloft should help thunderstorms to
persist into the lower deserts with further redevelopment during the
evening hours along expected deep and/or colliding outflows. The
ingredients for some severe thunderstorms are likely to be met on
Tuesday, especially across Pinal and southern Maricopa counties. If
enough convection can form along the Mogollon Rim in the afternoon,
this may provide for colliding outflows and decent thunderstorm
development over Phoenix, but this is still uncertain. The main
thunderstorm impacts on Tuesday should be strong to potentially
severe winds along with areas of blowing dust. Heavy rainfall will
also be a threat, but given the easterly steering flow of 10-15 kts,
any flash flooding should be quite localized. By late evening, an
organized thunderstorm outflow with blowing dust and even some
isolated thunderstorms are likely to continue to progress westward
through southwest Arizona reaching the Yuma area by midnight.
Guidance then shows the inverted trough moving over the northern
Gulf of California by Wednesday afternoon. Storm chances for
Wednesday are quite uncertain at this time, but given the likely
active monsoon day on Tuesday, Wednesday should be much quieter. The
best areas for possible showers and storms on Wednesday may be
across southwest Arizona into southeast California and possibly
across the Arizona higher terrain. Temperatures Wednesday will also
be noticeably cooler with highs only between 103-106 degrees in the
Phoenix area to 105-109 degrees across the western deserts.
Starting Thursday, guidance shows drier air already beginning to
move into the western deserts and more dry air moving out of the
southeast into Arizona Friday into Saturday. This should mostly end
rain chances across the western deserts on Thursday and severely cut
back chances across the south-central Arizona lower deserts by
Friday. At the same time, the subtropical high is forecast to
restrengthen and recenter itself over New Mexico. This is expected
to bring hotter temperatures back over our region late this week
into the weekend with highs at or just over 110 degrees returning by
Saturday.
&&
.AVIATION...Updated at 2320Z.
South Central Arizona including KPHX, KIWA, KSDL, and KDVT:
No major aviation concerns are expected over the next 24 hours.
Winds will continue to follow typical diurnal trends, with
occasional gusts early this evening around 15-20 kts. There hints
of an outflow boundary moving through the region tonight but
confidence surrounding this boundary is low and therefore not
included in the TAFs at this time. However, if an outflow were to
be realized, it would likely turn the winds to the E/SE earlier
than was is currently in the forecast, and produce gusts near
20-25 kts for a brief period. Skies will be generally SCT, to
perhaps sometimes BKN, through tomorrow morning, with the lowest
bases around 12k ft.
Southeast California/Southwest Arizona including KIPL and KBLH:
No major aviation weather concerns are expected through the TAF
period. Winds at IPL and BLH through much of the period will
emanate out of the SE and S respectively. Hi-res guidance points
towards a potential outflow boundary moving through the region by
mid-morning Tuesday but overall confidence in this is low. If this
outflow were to come to fruition, it would likely emanate out of
the S/SE and push gusts towards 20-25 kts at both terminals for a
brief time. FEW-SCT mid and high level clouds will be present
through Tuesday morning, before skies begin to gradually clear.
&&
.FIRE WEATHER...
Moisture will be on the increase through Tuesday with a
disturbance approaching the region from the east. Thunderstorm
chances today should mainly be confined to higher terrain areas,
while Tuesday will bring widespread chances (30-50%) for showers
and thunderstorms through much of the Arizona lower deserts. On
Wednesday, wetting rain/storms will likely be much less widespread,
especially if we have an active day tomorrow, but the western
deserts could see isolated thunderstorm development over prominent
terrain features. Aside from thunderstorm outflows, winds should
remain light and diurnal today before increasing southerly winds
are expected tonight. MinRHs will be around 15-20% today before
increasing to 20-25% on Tuesday and Wednesday. Overnight
recoveries will improve through Tuesday night increasing from
30-45% to 45-60%. Temperatures will cool down closer to normal by
Wednesday with shower and thunderstorms remaining through midweek.
Drier conditions will eventually move back into the area late
week into next weekend with rain chances retreating to only over
higher terrain AZ areas and temperatures heating back up to over
110 degrees.
&&
.CLIMATE...
Phoenix Daily Record Temperatures
High Warm Low
---------- ----------
8/5 116 (2023) 95 (2009)
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...Excessive Heat Warning until 8 PM MST Tuesday for AZZ530-532.
Excessive Heat Warning until 8 PM MST this evening for AZZ531-
533>555-559-560.
CA...Excessive Heat Warning until 8 PM PDT Tuesday for CAZ560>570.
&&
$$
DISCUSSION...Whittock
PREVIOUS DISCUSSION...Kuhlman
AVIATION...RW
FIRE WEATHER...Whittock/Kuhlman
CLIMATE...Benedict
Area Forecast Discussion
National Weather Service Reno NV
122 PM PDT Mon Aug 5 2024
.SYNOPSIS...
* Dry, southwest flow prevails this week with typical afternoon
breezes each day. Localized enhanced fire weather concerns
possible today and Tuesday.
* Above average temperatures persist through the week, with a
moderate HeatRisk for lower elevations.
* Plan on a slight cooling trend to near normal August
temperatures for the weekend.
&&
.DISCUSSION...
* Dry and Warm This Week: Dry, southwest flow will dominate across
the region as the western extent of a high pressure ridge
extends into the southern half of NV. Latest short and medium
range guidance still shows potential for late day cumulus
buildups in areas south of Highway 50 through much of this week
which could produce a few brief showers, but potential for
measurable precipitation is less than 10% areawide. Temperatures
will be about 3 to 6 degrees above early August averages, with
highs in the upper 90s-near 100 for the lower valleys and mid-
upper 80s for Sierra communities.
* Winds and Fire Concerns: With the warm temperatures, our typical
afternoon southwest-west breezes return each day through the
week. This could lead to short periods of elevated fire weather
concerns for isolated portions of northeast CA/northwest and far
western NV with afternoon wind gusts 25-30 mph and minimum RH
down to 10-15%. Latest HRRR smoke forecasts from existing fires
in northern CA show minimal smoke impacts for much of the
region. However, parts of northeast CA and northwest NV are
projected to see a return of smoke/haze later today and again
Tuesday afternoon with the Park Fire showing increased activity
due to the warmer, drier and breezy conditions.
* Cooler Weekend into Next Week: Ensemble cluster analysis
highlights an upper level trough dropping into the Pacific
Northwest Friday-Saturday which pushes the high pressure ridge
away from CA/NV. This would lead to a gradual drop in
temperatures to near mid-August averages for the weekend. We
could also see some increased winds arrive this weekend if the
trough continues progressing farther south, with additional
cooling to slightly below average by early next week. Most
scenarios keep dry weather over CA/NV, but a few simulations
(about 10%) that evolve the trough into a closed low over
northern CA could generate isolated rain showers by early next
week. MJD
&&
.AVIATION...
* Plan on VFR conditions this week along with typical afternoon
breezes. Daily southwest to west wind gusts of 20-25 kts will
develop between 21-03Z. Some minor reductions in slantwise
visibility will be encountered in northeast CA/northwest CA due
to haze from ongoing fire activity.
* Dry, southwest flow will limit precipitation chances for much of
the week, but a few cumulus buildups and brief showers are
possible for areas south of Highway 50. MJD
&&
.REV Watches/Warnings/Advisories...
NV...None.
CA...None.
&&
$$
Area Forecast Discussion
National Weather Service Tucson AZ
123 PM MST Mon Aug 5 2024
.SYNOPSIS...A disturbance aloft will result in an active monsoon
pattern for Tuesday with numerous showers and thunderstorms,
especially from Tucson westward. Otherwise, expect scattered showers
and thunderstorms each day through this week, with potential for
heavy rainfall and strong wind gusts. Temperatures cool to near
normal levels Tuesday through Thursday, then warm up to above normal
levels Friday through the weekend.
&&
.DISCUSSION...Latest IR/WV satellite imagery shows mostly sunny to
partly cloudy skies across southeast Arizona. The subtropical
mid/upper level high is currently east of the Four Corners with an
inverted trough now pushing into Chihuahua from west Texas. This
feature will have a more significant impact on our weather Tuesday.
In the near term, scattered showers and thunderstorms are a bit
slower to develop today than we`ve seen the past couple of days. The
HREF/CAMs are showing the bulk of these scattered showers and
thunderstorms through the afternoon to the south and east of Tucson
primarily near the Int`l border from Nogales eastward and then
another area in the White Mountains. The HRRR has been consistent
for a number of runs in bringing another push of storms from the
Gila region of New Mexico pushing westward this evening and perhaps
through the Tucson area after about 8 or 9 PM this evening. Main
concerns today into this evening will be gusty winds and locally
heavy rain.
The aforementioned inverted trough will move into NE Sonora Tuesday.
This will result in a stronger mid level flow of around 15 to 20 kts
from the east and additional synoptic scale lift to result in an
expected active afternoon and evening for monsoon thunderstorms.
There will be a push of moisture northward from the Gulf of
California/Sonora tonight which will help increase the PWAT levels a
couple tenths of an inch compared to today. This additional moisture
combined with daytime heating should result in widespread SBCAPE
values of 1000-2000 J/KG with DCAPE values near 1500 J/KG. This
setup is favorable for both strong to severe thunderstorms with a
wind threat and a flash flooding threat. The SPC has outlined much
of our area in a marginal risk for severe thunderstorms due to wind
and the WPC also depicts much of the area in a slight risk for flash
flooding. The strongest storms based on the HREF are expected to be
from Tucson westward. The faster flow will help storms move along at
a decent clip but locales that see cell mergers will be most
susceptible to flash flooding. Additionally, blowing dust will be a
threat to the west and northwest of Tucson late Tuesday afternoon
into Tuesday evening.
The amount of monsoon activity Wednesday will somewhat be dependent
on how worked over the atmosphere is Tuesday. The inverted
trough/upper low does hang around the northern Gulf of
California/adjacent northern Baja through much of the week with our
under southeasterly flow. This pattern should yield a continuation
of daily thunderstorm chances with day-to-day specifics still
uncertain. Near normal temperatures are expected Tuesday through
Thursday, then warmer temperatures return Friday through the weekend
as heights increase with perhaps a bit of drying.
&&
.AVIATION...Valid through 07/00z.
Scattered -SHRA/-TSRA thru 06/06z then diminishing thereafter
Tuesday morning. Another round of Scattered to Numerous -SHRA/-TSRA
expected to develop aft 06/19Z. MVFR conds and local gusts to 50
kts near thunderstorms. Outside of thunderstorms expect wind speeds
less than 12 kts and following typical diurnal trends. Aviation
discussion not updated for TAF amendments.
&&
.FIRE WEATHER...Scattered to numerous showers and thunderstorms
are expected Tuesday, otherwise expect scattered showers and
thunderstorms each day this forecast period. Min RHs will trend
upward Tuesday through Thursday to about 25 to 50 percent in
valleys, then decreasing to around 20 to 30 percent Friday through
the weekend. Outside of thunderstorm winds, 20-foot winds will
generally be 15 mph or less, with afternoon/early evening gusts to
20-25 mph and light winds overnight.
&&
&&
.TWC WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
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