Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 08/04/20
AREA FORECAST DISCUSSION
National Weather Service Albany NY
1143 PM EDT Mon Aug 3 2020
Scattered showers and a few thunderstorms in advance of
Hurricane Isaias will move across the region tonight. A steady
light to moderate rainfall is expected for much of Tuesday as
Isaias tracks toward our area. Isaias will then move across the
region later Tuesday afternoon through Tuesday evening and bring
moderate to heavy rainfall and gusty winds. High pressure
builds in on Wednesday with drier weather.
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
As of 11:30PM, an area of showers and some embedded
thunderstorms are advancing into the mid-Hudson Valley and
Litchfield County, CT and should push in the Berkshires over the
next hour. However, behind this area, precipitation is much
weaker and disorganized. Latest HRRR suggests this area expands
and intensifies as it pushes northward into the ALY CWA through
the pre-dawn hours. We continue to show likely POPs after 06 UTC
but if this does not materialize, we will have to trends POPs
back. Given the lack of instability as per SPC mesoanalysis and
tight baroclinic zone for the incoming tropical moisture to
override, the HRRR may be overdone.
Even so, scattered showers and some areas of steadier area are
still expected overnight as moisture from what is now Hurricane
Isaias continues streaming northward between the trough over the
Great Lakes and sub-tropical high over the western Atlantic.
This pattern is somewhat reminiscent of a 80kt+ southwesterly
jet Predecessor Rainfall Event (PRE) per CSTAR research, where
tropical moisture is advected poleward of the TC and encounters
ascent in the right entrance region of the upper level jet.
Expected placement of this rain is across much of eastern New
York into far southwestern Vermont. Lesser activity is likely
across southeastern Vermont, the Berkshires and Litchfield
County. Lows tonight will bottom out in the mid to upper 60s
(with some upper 50s across parts of the Adirondacks).
Hurricane Isaias officially made landfall near Ocean Isle, NC
around 11:10PM with maximum sustained winds 85mph which is a
category one hurricane. Impressively, a buoy near the NC coast
reported a minimum pressure of 988mb with a weather station near
Oak Island reporting a gust to 87mph. Fore more information,
visit hurricanes.gov Latest National Hurricane Center predicts
Isaias to downgrade back to a Tropical Storm by early Wednesday
morning as it reaches the mid- Atlantic.
.SHORT TERM /6 AM TUESDAY MORNING THROUGH WEDNESDAY NIGHT/...
Tropical Storm Isaias will affect the region with moderate to
heavy rainfall, gusty winds and the potential for a tornado or
two Tuesday through Tuesday night. Drier weather returns on
Early Tuesday morning, the latest NHC forecast projects Isaias to be
located inland across eastern Virginia and will continue on a
northeasterly track toward eastern New York later Tuesday afternoon
into Tuesday evening and then into southern Quebec by early
Wednesday. Isaias is expected to hold tropical storm intensity as it
passes across the region with the potential for a slow transition to
an cyclone as it does so.
Moderate to heavy rainfall will be the primary threat with Isaias.
Tuesday will begin with continued light to moderate rainfall with
the greatest corridor being across much of eastern New York into
southwestern Vermont with less coverage across southeastern Vermont,
Berkshire County and Litchfield County. As Isaias passes through
later Tuesday afternoon into Tuesday evening, a 3- to 6-hour period
of heavy rainfall is expected (especially just to the west of the
low track). This rainfall will be aided by strong low to mid-level
frontogenesis and a juicy airmass (with precipitable water values of
1.75 to 2.25 inches). Rainfall rates of 1-2 inches per hour will be
possible. Total rainfall of 2-4 inches is expected with locally
higher amounts (especially in the upslope-favored locations). Lesser
amounts are expected in Herkimer County, which is expected to be on
the western edge of the heavier rain (general 1-2 inches). The Flash
Flood Watch will remain in effect for all of the forecast area
outside of Herkimer County. The greatest flooding concerns will be
in low-lying and urban areas.
Wind will also be an impact with wind gusts up to 50 mph possible.
This would most likely occur in heavier periods of rain or
convective elements as the intensity of the rain could aid in
transporting strong low-level winds (50-60 kt at 850 hPa) down to
the surface. With this potential, a Wind Advisory has been issued
for the eastern Catskills, Hudson Valley and southern Vermont valid
late Tuesday afternoon through Tuesday evening. A Tropical Storm
Warning is in effect for Berkshire and Litchfield counties to
account for the wind threat as well.
The final impact from Isaias will be the threat for isolated
tornadoes on its northeastern quadrant. At this time, this includes
areas south and east of the Capital District as per the latest
outlook from the SPC.
With the combination of the clouds and rain, high temperatures will
only reach the upper 60s across the higher elevations to the low to
mid-70s in the valleys.
As this system departs, a few lingering showers are possible on
Wednesday morning, mainly across the Adirondacks, then a drier and
less humid air mass moves into the region as surface high pressure
builds in from the west. Highs on Wednesday will reach the 70s to
lower 80s with lows Wednesday night mainly in the 50s.
.LONG TERM /THURSDAY THROUGH MONDAY/...
A quiescent weather pattern in the wake of TC Isaias is on tab for
the long-term period. The primary driver of our sensible weather
over eastern New York and western New England will be a surface high
pressure system. This will bring plenty of subsidence and abundant
sunshine over the area through much of the period.
There`s a low grade risk (20% PoPs) for showers and storms over the
area on Monday as mid to upper energy approaches from the west. The
area on Monday should remain rain-free. The better chance for
precipitation will be on Tuesday as the mid to upper energy is
progged to be in closer in proximity to the FA.
Surface temperatures during the extended will gradually trend
higher/warmer going from closer to seasonable levels to slightly
above average. This will largely be due to the fact that higher
heights will be building over the FA as we move forward in time.
High temperatures in the upper 70s to lower 80s is expected in the
valleys (cooler higher elevations) at the onset of this period
increasing to the mid 80s late in the period. Low temperatures will
start off in the upper 50s to lower 60s across the valleys at the
start of the extended increasing into the mid to upper 60s late
(cooler higher elevations). Humidity levels will also be on the
increase during this time frame.
.AVIATION /04Z TUESDAY THROUGH SATURDAY/...
Main weather concerns for the terminals through the TAF period
surrounds the impending impacts from Tropical Cyclone Isaias.
Current satellite imagery depicts SCT-BKN VFR mid strato-cu mixed in
with some high Ciro-stratus clouds over eastern New York and
western New England. Ahead of TC Isaias, cloud levels will
gradually lower as the afternoon and evening wears on.
Rain with some embedded thunder will develop tonight over the area
from south to north beginning between the hours of 01z-06z. Any
showers or storms will have the potential to bring cigs/vsbys
down to MVFR levels.
Winds this afternoon into this evening will be out of the west-
southwest and 5-10 kts. Tonight, winds will become light and
variable before shifting out of the south-southeast 5-10 kts by
Tuesday Night: High Operational Impact. Windy With Gusts To 39 kts. Definite SHRA...RA...TSRA.
Wednesday: No Operational Impact. NO SIG WX.
Wednesday Night: No Operational Impact. NO SIG WX.
Thursday: No Operational Impact. NO SIG WX.
Thursday Night: No Operational Impact. NO SIG WX.
Friday: Low Operational Impact. NO SIG WX.
Friday Night: No Operational Impact. NO SIG WX.
Saturday: Low Operational Impact. Slight Chance of SHRA...TSRA.
Showers will return to the region tonight and continue through
Tuesday afternoon. Heavy rain associated with Tropical Cyclone
Isaias will move across the area late Tuesday afternoon through
Tuesday evening before ending late Tuesday night. RH values will
remain high through tomorrow.
Periods of rain associated with the northward progression of TC
Isaias is expected Monday night through Tuesday night. The
heaviest rainfall looks to occur late Tuesday afternoon through
Tuesday evening as the storm makes its closest approach. QPF of
2-4" is expected, with locally higher amounts up to 6" possible.
Here, rainfall rates could exceed an inch per hour, and there
could be 2-4" in a 3- hour period between 18Z Tuesday and 06Z
The heavy rainfall rates have the potential to cause flash flooding
in urban, poor drainage and low lying areas. Smaller streams and
creeks may also flood their banks due to the heavy rainfall
rates. A Flash Flood Watch remains in effect for the entire HSA
except for Herkimer county.
The ALY Hydro Service area continues to be in Abnormally Dry to
Moderate Drought conditions /D0 to D1/ based on the latest US
Drought Monitor. The latest MMEFS guidance continues to show low
probabilities for widespread river flooding.
Drier weather will return into the mid week period.
For details on specific area rivers and lakes, including observed
and forecast river stages and lake elevations, please visit the
Advanced Hydrologic Prediction Service /AHPS/ graphs on our
CT...Flash Flood Watch from 8 AM EDT Tuesday through Wednesday
morning for Ctz001-013.
Tropical Storm Warning for Ctz001-013.
NY...Flash Flood Watch from 8 AM EDT Tuesday through Wednesday
morning for Nyz038-039>043-047>054-058>061-063>066-
Wind Advisory from 2 PM Tuesday to 1 AM EDT Wednesday for
Nazi-043-047>054-058>061-063>066-083-084. MA...Flash Flood
Watch from 8 AM EDT Tuesday through Wednesday morning for
Maz001-025. Tropical Storm Warning for Maz001-025. VT...Flash
Flood Watch from 8 AM EDT Tuesday through Wednesday morning for
Ctz013>015. Wind Advisory from 2 PM Tuesday to 1 AM EDT
Wednesday for Ctz013>015.
Area Forecast Discussion
National Weather Service Denver/Boulder CO
809 PM MDT Mon Aug 3 2020
Issued at 804 PM MDT Mon Aug 3 2020
Kind of another dud day along the Front Range with the best pulse
storm earlier southeast of Denver and over the southern Front
Range foothills this afternoon. The rest of the plains have been
quiet so far. Radar imagery showing some weak convection now along
the Continental divide with light showers and some wind, while
another batch of weakening convection over southeast Wyoming which
is skirting our far northern plains with scattered showers.
Evening sounding at KDNR still had some promise with just an ever so
weak cap in place and a bit surprised we didn`t have more storms.
Water vapor imagery did look somewhat subsident over the Denver area
and right under the jet streak so maybe this feature has squashed
convection somewhat. Hi resolution models don`t have much stronger
convection overnight but a bit concerned about outflow from storms
coming off the hills in the next few hours and potential to light up
more convection. Will at least keep in some low pops for the rest
of the evening, and somewhat higher pops up further north towards
Wyoming and Nebraska.
.SHORT TERM...(This evening through Tuesday)
Issued at 218 PM MDT Mon Aug 3 2020
Latest ACARs sounding from early this afternoon has a moderate
northwesterly flow aloft over the region with 70 kts around 200
mb. RAP ML CAPES around 1500 j/kg with EFF Shear 30-35kts. A
dissipating cell produced a peak wind gust to 60 mph earlier this
afternoon in Walden. Storms this afternoon moving fairly fast, so
any heavy rainfall that develops should be brief. Latest HRRR for
this afternoon and evening, seems to have the highest
thunderstorm coverage over western and southern portions of the
Denver area, moving most of those storms into the Palmer Divide by
early this evening. Strong wind gusts to 60 mph and hail around
one inch the main impact from the stronger storms. Less coverage
elsewhere, but another cluster of thunderstorms impact northeast
We and Logan counties late this evening. Isolated thunderstorms
may linger over the far northeast plains after midnight, but quiet
On Tuesday, another round of thunderstorms expected. Instability
and shear parameters will continue to allow for marginal or slgt
risk of severe thunderstorms. Large hail and damaging winds the
main threats, similar to the last few days. ML CAPE values closer
to 2000 j/kg in the Tuesday afternoon. High temperatures similar
to today as well.
.LONG TERM...(Tuesday night through Monday)
Issued at 218 PM MDT Mon Aug 3 2020
Thunderstorms that formed earlier in the day will be tracking
southeast across the eastern plains. Still a chance a few storms
could develop along the Front Range as well. With MLCAPE of 1500-
2000 J/kg and Bulk shear of 35-45 knots some of the storms are
expected to be strong to severe during the early evening. Most, if
not all the convection is expected to end by midnight as the
Northwest flow aloft will persist into Wednesday around an upper
level ridge that extends from the Southern Rockies northwest to
the Great Basin. Southeasterly low level flow will keep low level
moisture across the Front Range and eastern plains. MLCAPE climbs
up to 2000 J/kg Wednesday afternoon with Bulk shear of 30-40
knots. This should result in some strong to severe storms
Wednesday afternoon and evening. With little change in the
airmass, high temperatures will be similar to the past few days
as readings reach the mid to upper 80s.
The upper level ridge axis shifts eastward and will move across
Colorado Thursday. This will result in a westerly flow aloft. A
trough of surface low pressure will be somewhere along the Front
Range. To the east of it, enough moisture and instability will
exist for another round of scattered strong/severe storms. To the
west of the boundary, it will be drier with isolated high based
convection. Temperature are expected to warm a little with upper
80s and lower 90s across northeast Colorado.
For Friday through Monday, the upper level ridge sets up over the
Southern and Central Rockies. This will result in a west to
southwest flow aloft depending on where the center is. Drier and
warmer air will be transported into the area. This will cause the
chance for rain to decrease. High based showers and storms will be
possible most day over the higher terrain with a few moving off
to the east. Gusty winds and light rainfall will main features
with the convection. If low level moisture is able to sneak in
from the east. Stronger storms will be possible. Highs are
expected to climb into the 90s each day.
.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 804 PM MDT Mon Aug 3 2020
Strong outflow southerly winds have impacted DEN/APA over the past
hour with some weakening in the overall winds expected through 03z
with light drainage winds the rest of tonight. The caveat is
showers that are moving over the mountains now and may impact the
terminals with w-nw winds and some showers between 03-05z. Might
need to make some adjustments with this in upcoming updates to
account for this.
Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
720 PM EDT Mon Aug 3 2020
The initial wind shift has cleared all the terminal locations early
this evening. Surface winds have flopped to light northerly and will
hold that condition throughout the forecast window. Scattered
convective showers have resided north the Detroit terminals and will
slowly dwindle with the loss of boundary layer heating. Additional
showers are strung out along the primary cold front extending from
Saginaw Bay southwest through the Lansing region - which will
continue to perk as the colder air aloft washes over the relative
warm boundary layer resident over much of Southeast Michigan.
Expect a window of improving sky conditions across the southern
terminals before the arrival of the solid MVFR cloud field
associated with a secondary surge of colder air over Northern Lower
Michigan. Additional scattered light shower activity is expected to
develop overnight within this cohesive cloud shield - especially
across the MBS and FNT airspace. Coverage and intensity will be
inconsequently to aviation impacts.
For DTW... Winds will be somewhat confused during the first hour or
so as the northerly flow behind the initial wind shift mixes with a
east/northeast flow behind a weak convective outflow working west
across Wayne County. Sub-5kft ceilings will become well established
late this evening. A shower is possible on the lead edge of the
better cloud cover. These clouds will maintain through the night.
Expect ceilings to slowly lift and possibly break during the peak
heating hours of Tuesday.
.DTW THRESHOLD PROBABILITIES...
* High for ceiling aob 5000 tonight and Tuesday.
* Low for a thunderstorm this evening.
Issued at 343 PM EDT Mon Aug 3 2020
Global datasets depict an impressive ridge of +980dam H3 heights
over Bermuda or 30N 60W. Efficient blocking is in place on the
immediate cyclonic shear side of the high amplitude ridge, virtually
over all of eastern North America. Locally, Southeast Michigan
continues to feel the effects of neutral to even slightly positive
height rises due to the exit of the shortwave Sunday. However,
definite positive d/dt increase in entrance region dynamics is
occurring across the Lake Huron basin southwestward with a foot here
in Southeast Michigan. The synoptic scale forcing is well organized
and strong enough to both induce surface low reflection over
Southeast Michigan and stave off subsidence based dry advection/cold
front (note surface observations across Northern Lower Michigan)for
the next 18 hours or so.
Special 18Z DTX raob and RAP based mesoanalysis supports a deep
convectively unstable column with weak static stability through
tropopause at 35 kft agl. The atmosphere remains weakly sheared with
a unidirectional wind profile and less than 30 knots of environmental
wind through 15 kft agl. Virtually no CIN exists across much of
Southeast Michigan evidence by the numerous coverage of shower and
thunderstorm activity. Two boundaries have provided a focus to
development here this afternoon, the first is along a line from Port
Huron to Mount Pleasant, the second from Port Huron southward along
the rivers to Carlton. Given the weak forcing, its been difficult to
ascertain the driving mechanisms behind the boundaries. The northern
boundary is probably some convergence maximum of the aforementioned
weak surface reflection low and convective outflow from earlier
Saginaw Bay thunderstorm activity, whereas the the north to south
boundary along the rivers appears to be an artifact of enhanced
convergence on western flank of pseudo warm sector/diabatic heating
tongue through Lake Erie and far Southwestern Ontario. Given the weak
forcing, expectations are for continued weak/mushy convective
activity through the daylight hours. Loss of daytime heating will
lead to development of capping inversion around 4.5 kft agl. No
organized severe weather threat expected this afternoon. Potential
exists for isolated strong to severe thunderstorm with damaging
windgusts to 60 mph possible due to wet microbursts/waterloading. The
observed rainfall rates today have been supportive of localized
flooding with training or slow moving thunderstorm activity. Earlier
today radar estimates suggest as much as 3.5 to 4.0 inches of rain
fell over portions of northeastern St Clair County/near Port Huron.
This potential will continue this afternoon although broad parameters
for heavy rainfall are not that extreme, PWATS at or less 1.5 inches
and very weak midlevel moisture transport vector.
Complex evolution of the upper level trough will cause a main lobe
of PV to pivot across Southeast Michigan on Tuesday. Models show
that loss of entrance region dynamics will cause tenuous warm sector
to be shunted eastward. Models showing organized low level cold air
advection taking hold of all of the state. Really some competing
interest on whether or not a large coverage of shower activity can
develop. Large scale height falls are expected to be in place as
well as the main composting trough axis. Forecast soundings are not
nearly as supportive with deep column subsidence limiting convective
depth potential to less than 5000 ft agl. Suspect the pocket of
steep lapse rates will result in cumulus/overcast for the area, but
will not be enough to generate much outside of some brief low
QPF/sprinkles particularly downwind of Saginaw Bay.
Seasonally more comfortable weather will carry over on Wednesday
with dewpoints in the 50s. The air mass will then begin to moderate
during the end of the week as deep column ridging takes hold.
Sprawling surface high pressure is expected to be in place, leading
to quiet weather through at least the first half of the upcoming
Small Craft Advisories remain in effect for southern Lake Huron
tonight through Tuesday as cool northerly wind becomes established.
The wind pattern follows low pressure exiting the Port Huron area
toward Georgian Bay tonight. Thunderstorm coverage decreases near
shoreline areas during the evening but the cool air over the warm
lake water maintains adequate instability for scattered showers and
a chance for waterspouts tonight through Tuesday. High pressure then
gains territory over the central Great Lakes Tuesday night leading
to favorable marine conditions for the mid week period.
Lake Huron...Small Craft Advisory until 10 PM EDT Tuesday for LHZ441>443.
Small Craft Advisory until 10 PM EDT this evening for LHZ422.
Small Craft Advisory until 10 PM EDT Tuesday for LHZ421.
Lake St Clair...NONE.
Michigan waters of Lake Erie...NONE.
You can obtain your latest National Weather Service forecasts online
Area Forecast Discussion
National Weather Service Melbourne FL
1022 PM EDT Mon Aug 3 2020
Looks to remain mostly dry through the rest of the night. Latest
HRRR guidance has been indicating scattered showers developing
late tonight across central/southern sections of east central
Florida. However, MOS and hi-res model guidance has been
overplaying rain chances by quite a bit. Will therefore keep rain
chances largely out of the forecast for land areas, except for
some slight chance PoPs toward the Treasure Coast late. Better
potential for any redeveloping showers and possibly a few storms
will be over the gulf stream after midnight. Skies will be mostly
clear with lows in the 70s.
.AVIATION...Dry air behind Isaias continues to keep convection very
limited this evening. VFR conditions through the TAF period. Winds
this evening are from the W at 5-10KT for the inland sites, and out
of the SE at 5-10KT along the coast. The sea breeze has formed and
is moving inland. Took all mention of precip out for the evening and
overnight hours. Boundary collisions along the sea breeze may
produce showers, but the dry stable air will make the convection
short lived. Tomorrow, winds will start off SW around 5KT before
veering to WSW/W at 5-10KT by late morning. By the afternoon the
winds will back to the SE around 10KT along the coast as the sea
breeze forms and moves inland. Included VCTS for all sites starting
.MARINE...Southerly winds around 10-15 knots will persist
offshore tonight. Have allowed all SCA headlines to expire as
seas continue to decrease with Isaias moving farther away from the
area. However, will continue exercise caution headlines offshore,
north of Sebastian Inlet, for lingering seas up to 6 feet.
.PRELIMINARY POINT TEMPS/POPS...
DAB 75 93 76 91 / 10 60 30 60
MCO 76 95 77 92 / 10 60 30 60
MLB 75 90 78 89 / 10 60 30 60
VRB 75 91 76 90 / 20 60 30 60
LEE 77 95 78 94 / 10 50 20 60
SFB 77 95 76 94 / 10 60 30 60
ORL 78 95 77 93 / 10 60 30 60
FPR 73 92 77 91 / 20 60 30 60
Area Forecast Discussion
National Weather Service Riverton WY
548 PM MDT Mon Aug 3 2020
.SHORT TERM...(This afternoon through Tuesday evening)
Short-wave trough currently moving from northeast Idaho into
central Montana in west-southwest mid- to upper-level flow. Mid-
level lapse rates greater than 9 have helped isolated convection
start before noon today and increased cloudiness to western WY a
bit earlier than expected. Forecast still on track for scattered
showers and thunderstorms to the northeast two-thirds of the area,
primarily east of the divide. SPC has a Marginal Risk for severe
storms extending from northern YNP eastward to Big Horn County,
then southeast into Natrona County, and everything northeast. The
stronger storms are likely to produce hail around one inch and
40-60 mph wind gusts. Low-level helicity may help weak supercells
to develop as well. Though the HRRR is not capturing the late
morning convection, storms should generally develop by 2pm and
continue through about 8-9pm. Lingering showers and expected
across Johnson County through 2am. Southwest WY will see winds
increase from the west this afternoon with gusts 25-30 mph and
humidities below 15% for critical fire weather conditions.
As the system moves into the northern plains early Tuesday
morning, the trailing higher surface pressure will bring a cool
front into northern and central WY east of the divide. 700mb temps
are expected to drop by 4-6 deg C to bring max temps Tuesday to
near of below normal in the 80s. The exception will be southwest
WY where very warm, dry, and breezy conditions will continue the
critical fire weather conditions for another day. Tuesday
afternoon will see isolated convection over the mountains east of
the divide with the storms moving to the southeast, much like many
days last week. Weak ridging over the Intermountain West es
expected to develop late Tuesday/early Wednesday, weakening the
surface pressure gradient over the area and decreasing surface
winds. Increased cloudiness with very light showers should linger
across northern WY late Tuesday and the stationary boundary sets
up once again.
.LONG TERM...(After midnight Tuesday night through Sunday)
The models continue to indicate that a ridge will be building into
the region Wednesday from the southwest, with slightly warmer temps
expected. Will keep in a chance of mainly widely scattered
showers/storms on both Wednesday and Thursday afternoons due to weak
shortwaves moving mainly across north and into northeast Wyoming.
Southern sections of the forecast area will remain dry through
Thursday. As the ridge builds into the region on Thursday and
Friday, we will see an increase in southwest winds in the
afternoons, especially across the southern wind corridor from
Sweetwater and into Natrona counties. Fire weather conditions are
again expected to reach into the elevated status again especially
across the south on both Thursday and Friday due to the increased
winds. This could create some elevated fire weather conditions once
again. The models again hint that a minor shortwave will move east
across northern Wyoming on Friday with a few isolated storms
possible mainly in the northwest.
The GFS and ECMWF models are now indicating for the upcoming weekend
that the forecast area will remain in a ridge axis with mainly dry
conditions. Will not rule out an isolated shower or thunderstorm
across northwest Wyoming on Saturday and Sunday afternoons. Expect
high temperatures to remain in the 80s to low 90s except in the 70s
in the northwest.
.AVIATION...(For the 00Z TAFS through 00Z Wednesday)
Conditions will remain VFR at all terminals through 00Z/Wednesday.
Outflow boundary collisions with ongoing convection will persist
until around sunset with possible outflow wind impacts to terminals
east of the Continental Divide. Weak frontal boundary will push
through areas east of the Continental Divide late Tuesday morning
and afternoon with north-northeast wind in its wake. KRKS, KBPI, and
KPNA can expect gusty west-northwest wind to increase by early
Tuesday afternoon with gusts 20-25kts.
Disturbance moving from eastern Idaho into southern Montana today,
bringing scattered showers and thunderstorms to the northern and
eastern parts of the forecast area today. Some of the storms from
YNP to the Bighorns and into Johnson and Natrona Counties could be
quite strong, with hail and strong gusty winds. Dry, very warm, and
breezy to windy conditions expected for southwest and southern WY
this afternoon; thus a red flag warning in in effect from 1300 to
2000 today. Cooler northerly flow will push down east of the divide
early Tuesday morning. Isolated showers and thunderstorms, primarily
over the mountains, can be expected again Tuesday afternoon east of
the divide. Southwest WY will again see breezy west wind with dry
warm flow. The red flag warning continues for zones 277, 278, and
279 Tuesday afternoon. Wednesday looks to be an in between day with
continued cooler temps with some showers.
Thursday and Friday are shaping up for more elevated fire weather
conditions from southern into central WY.
Red Flag Warning until 8 PM MDT Tuesday for WYZ277>279.