Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 07/10/21
Area Forecast Discussion
National Weather Service La Crosse WI
1030 PM CDT Fri Jul 9 2021
.SHORT TERM...(This evening through Saturday)
Issued at 233 PM CDT Fri Jul 9 2021
Main focus is on rain/thunderstorm potential into Saturday.
Scattered showers/storms have been developing across southern MN
within an elevated frontal zone as a weak shortwave trough passes.
Late this afternoon into tonight, expect the primary instability
axis to remain south and west of the area with some modest MUCAPE
encroaching on southwestern portions of the area. Confidence isn`t
very high on how convection will evolve into tonight. In general,
though, think additional convection will ramp up along the nose
of low-level jet/moisture transport this evening. Although
guidance varies on the strength of the moisture transport,
generally the nose of the low-level jet is should focus across
central IA with storms quickly progressing southward into the
instability axis. With the surface-based instability and steeper
mid-level lapse rates relegated to areas farther southwest, not
expecting much for a severe weather threat, but could not rule out
some hail/gusty winds with any storms, especially across
northeast IA. Expect the greatest risk for heavy rainfall to be
south of the area, but any storms could produce high rain rates
and locally heavy rainfall if storms train over the same area.
A surface low is expected to move towards the Mid-MS Valley on
Saturday ahead of the deepening upper trough. Overall there
appears to be a trend for at least some showers to spread across
at least southern parts of the region on Saturday with shortwave
energy lifting across the area downstream from the main trough and
mid- level deformation. Instability looks quite limited north of
the surface low so thunder chances should be low. If the
cloudier/showery solution holds, some locations could remain in
the 60s for highs.
.LONG TERM...(Saturday night through Friday)
Issued at 233 PM CDT Fri Jul 9 2021
The potential for additional rain across the southern part of the
area through the weekend and into early next week still looks to
be in flux with plenty of uncertainty involved. Water vapor
satellite imagery shows a couple of short wave troughs topping the
western Conus ridge today. The first wave will slide through
tonight and is expected to be responsible for the severe weather
outbreak to the south of the local area. The second wave will then
slide into the region late tonight into Saturday and is expected
to have an upper level low develop with it over the Missouri River
Valley. This scenario is generally agreed upon by the models but
with some subtle differences in the placement of where the upper
level low will be. These differences in turn impact how far north
any associated rainfall may be. Give the uncertainty of where the
upper level low may actually be, the rain chances will have to
cover the most pessimistic outcome, which comes from the 09.12Z
GFS which shows the potential for rain over much of the area from
Sunday into Monday. The rain chances could possibly even extend
into Tuesday depending of how fast (or slowly) the systems lifts
out of the region. If this does occur, it should primarily just be
showers as there looks to be little potential for CAPE
development thus keeping the thunder threat pretty low.
There looks to be another good shot at some widespread rains by
the middle of next week. An upper level low should be moving
across southern Canada with the trough extending south over the
Upper Midwest. An embedded short wave trough in the mean long wave
trough should help to generate showers and storms Wednesday and
Wednesday night. It`s too early to know what the severe threat
might be with this activity. The 09.00Z ECMWF would suggest the
best CAPE stays to the south of the area with the deep layer shear
also staying primarily to the south. The models are again showing
differences in the timing of when this system may clear out of
the region which will means the rain chances will persist in the
forecast through the end of the next week.
&&
.AVIATION...(For the 06Z TAFS through 06Z Saturday night)
Issued at 1030 PM CDT Fri Jul 9 2021
Cigs: challenging forecast with cutoff upper level low hanging
around the region, likely just south of the TAF sites. The MVFR/VFR
line of clouds will be close as a result, with latest RAP holding it
just south of KLSE but touching KRST. HRRR suggestive of the
same thing. Improvement trending then for the evening. Not a ton of
confidence here, but will follow these trends for now.
WX/vsby: bulk of associated shra/ts with this system looks to hold
just to the south. Could run into isold/sct convection around I-90
sat afternoon, but not a lot of agreement in the short term
models...so will keep dry for now and add if probabilities increase.
Winds: east mostly 10 kts or less through the day Sat, looking to
become more northeast/north later Sat night.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...None.
IA...None.
&&
$$
SHORT TERM...JM
LONG TERM...04
AVIATION...Rieck
Area Forecast Discussion
National Weather Service Bismarck ND
959 PM CDT Fri Jul 9 2021
.UPDATE...
Issued at 957 PM CDT Fri Jul 9 2021
Around 830 PM CDT this evening, an isolated shower produced a
funnel cloud in north central Mountrail County. With the loss of
diurnal heating contributing to weakening low level lapse rates,
atmospheric conditions are no longer expected to support the
development of funnel clouds.
Forecast expectations on both the coverage and intensity of
showers and storms through the night have greatly decreased since
previous updates. Convection has been much more sparse so far
this evening, and lightning has been nearly non-existent within
the state. It appears that 00Z guidance is catching onto these
trends. Notably, the local maxima of the 00Z HREF probability-
matched mean QPF from 00-12Z are less than 50 percent of their
values from the previous run. Furthermore, the 00Z Bismarck RAOB
only sampled 1.15 inches precipitable water. While Bismarck is
displaced to the west of the PWAT maximum, this value is still
around one to two tenths of an inch lower than what is being
simulated by the 00Z RAP and SPC Mesoanalysis. Taking all this
evidence into consideration, we have removed the mention of heavy
rain from the forecast. We will maintain the mentions of isolated
to scattered showers along with isolated thunderstorms, but
probabilities have been trended down. Lastly, the mention of
patchy fog was expanded based on the latest RAP guidance.
UPDATE Issued at 717 PM CDT Fri Jul 9 2021
Overall, only minor adjustments were made to the forecast with
this update. Scattered showers have shown a slight increasing
trend over the past few hours from north central North Dakota into
the James River Valley. Despite the presence of 1000-1500 J/kg
MLCAPE with little to no MLCIN, poor mid level lapse rates appear
to be a detriment to the lightning potential. Therefore, we have
limited the mention of thunderstorms to isolated this evening
through tonight. The focus for scattered shower and isolated
thunderstorm activity is still expected to pivot over south
central North Dakota tonight, mainly along and east of the
Missouri River. Precipitable water as high as 1.5 inches, warm
cloud layer depth greater than 3000 m, and slow storm motions will
promote a heavy rain potential with any shower or storm. However,
due to the scattered nature of the convection, the risk of heavy
rain will be highly localized, as can be inferred by 12Z HREF QPF
output.
Patchy fog was added to the forecast for parts of western and
central North Dakota late tonight into Saturday morning. This
potential is supported by a moisture-rich boundary layer with
light winds. Recent runs of the RAP were utilized to depict the
placement of the fog mention.
&&
.SHORT TERM...(This evening through Saturday)
Issued at 230 PM CDT Fri Jul 9 2021
Forecast highlights in the short term period will be chances for
showers and thunderstorms through Sat morning.
Currently, mid level circulation remains evident on satellite
imagery over southwest/south central North Dakota. Area of
associated showers persists over south central ND into portions of
the James River Valley. Extensive area of clouds also persists
across much of western and central ND, which has effectively cut
daytime high temperature potential by several degrees.
Another mid level trough will set up across the region later
today into tonight, resulting in another round of scattered
showers/storms from eastern Montana through central ND developing
later this afternoon and evening. Elevated atmospheric moisture
(PWATs 1.5 to 1.75") coupled with the mid level forcing and slow
storm motion will keep a threat for locally heavy rain over
portions of central North Dakota, so will maintain this wording
in products.
.LONG TERM...(Saturday night through Friday)
Issued at 230 PM CDT Fri Jul 9 2021
Seasonal temperatures and periodic chances for showers/storms
highlights the long term period.
Surface high pressure builds across the Dakotas on Saturday, with
lingering chances for showers across the southwest and south
central areas of North Dakota. Highs will range in the 80s as we
will see more sunshine compared to previous days.
Upper level ridge builds across the Northern Plains for Sunday,
resulting in warm and dry weather for the region.
Thereafter, we will be under a quasi-zonal flow regime Monday
through the end of the week, where we will see, on average,
seasonal temperatures and periodic chances for showers and storms
as several embedded waves move through aloft within the flow.
Extended models then strongly suggest a ridge of high pressure
building across the western CONUS and Rocky Mountains, which would
support a trend towards hot and dry weather as we near the last
week and a half of July.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 957 PM CDT Fri Jul 9 2021
Scattered showers are possible across much of western and central
North Dakota this evening through tonight, ending from north to
south by Saturday afternoon. The highest probability of showers is
at KJMS this evening, shifting to KBIS overnight. Ceilings are
likely to remain at VFR levels under showers, but visibility
reductions to MVFR or IFR levels are possible. Lightning cannot be
ruled out, but its probability is quite low. Additionally, patchy
fog may develop later tonight, with the highest potential at KDIK.
Outside of showers and fog, VFR conditions are expected with
light and variable winds.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...Hollan
SHORT TERM...NH
LONG TERM...NH
AVIATION...Hollan
Area Forecast Discussion
National Weather Service Boise ID
831 PM MDT Fri Jul 9 2021
.DISCUSSION...Increasing heat and smoke through the weekend.
The heat will be due to amplification of the upper ridge in the
Great Basin. The smoke will come in from two main fires, one near
Klamath Falls in south-central Oregon, and the other northwest
of Reno (in northeast California). With southwesterly flow aloft
the HRRR smoke model takes the Oregon smoke across Baker County,
the central Idaho mountains, and the Camas Prairie, while the
California smoke drifts over Idaho south of the Snake River.
That leaves the least smoke in Malheur County/OR and the Treasure
Valley through Saturday night. Skies will become smoky or at
least hazy everywhere and should take a degree or two off high
temps vs highs if the sky could stay clear. Even so, Saturday
will become about 10 degrees hotter than today, and Sunday
another couple degrees hotter than Saturday, and an Excessive
Heat Warning will be in effect from Saturday afternoon until
Monday evening in all zones except the Owyhee Mountains, west-
central Idaho Mountains, and Camas Prairie. No updates for now.
&&
.AVIATION...VFR. Smoke layers from wildfires will reduce
visibilities at times. Surface winds: generally southeast 5-15
kts. Winds aloft at 10k feet MSL: west 10-20 kts. Density
altitudes will remain high due to hot temperatures.
Sunday Outlook...VFR. Smoke layers from wildfires will reduce
visibilities at times. Breezy northwest winds in the afternoon.
Density altitudes will remain high due to hot temperatures.
&&
.PREV DISCUSSION...
SHORT TERM...Tonight through Sunday night...Upper level ridging
will expand over the region on Saturday, bringing warmer
temperatures. We are surrounded by wildfire smoke at this time,
so do not expect conditions to improve over the short term as
winds aloft begin to weaken and shift to the southwest.
Temperatures are expected to warm around 10 degrees on Saturday
and a few more degrees on Sunday with record highs possible.
Smoke will make the temperature forecast tricky, which may lead
to slightly cooler temperatures. Temperatures should still reach
100 in the lower valleys and the Excessive Heat Warning will
remain from Saturday afternoon through Monday afternoon. No
precipitation expected in the short term.
LONG TERM...Monday through Friday...Abnormally warm and dry
conditions are expected throughout the week as high pressure
remains locked in over the southwestern US. The ridge will
flatten somewhat, allowing for westerly flow to move over the
Pacific Northwest, but dry conditions are expected to persist.
Wildfire smoke could become an increasing threat during the
period.
&&
.BOI WATCHES/WARNINGS/ADVISORIES...
ID...Excessive Heat Warning from noon Saturday to 9 PM MDT Monday
IDZ012>016-030-033.
OR...Excessive Heat Warning from noon MDT /11 AM PDT/ Saturday to 9
PM MDT /8 PM PDT/ Monday ORZ061>064.
&&
$$
www.weather.gov/Boise
www.facebook.com/NWSBoise
www.twitter.com/NWSBoise
DISCUSSION...LC
AVIATION.....ST
PREV SHORT TERM...KA
PREV LONG TERM....MC
Area Forecast Discussion
National Weather Service Caribou ME
1135 PM EDT Fri Jul 9 2021
.SYNOPSIS...
Post Tropical Storm Elsa will track along the Downeast coast
this evening and move into the Maritimes early Saturday. High
pressure will cross the region Sunday through Monday. A warm
front will approach Tuesday then cross the region Wednesday.
&&
.NEAR TERM /THROUGH SATURDAY/...
942 PM Update: Took down Flash Flood Watch and the last Flood
Advisory. Rain will be ending in eastern Aroostook County in the
next two hours and the heaviest rain has moved out of the area.
Prev Disc: Post Tropical Elsa will track near the Gulf of Maine/
Downeast coast this evening and overnight. Main hazards remain
heavy rainfall along the coast, Downeast, and Southern Aroostook
tonight. Additionally, there is a threat for a few higher wind
gusts this evening, particularly along the saturated ground
along the coast and central Washington County. High surf
continues along the coast through Sat morning.
For rain, much of the guidance continues to show the risk for
flash flooding as Elsa pivots along the coast. This is based on
WPC/RFC flash flood guidance as well as QPF. MRMS based CREST
has been increasing across southern Maine as the main pivot
point wraps around a large swath of synoptic rainfall currently
falling up to 1" an hour. While Downeast is certainly a focus
for this evening into tonight, the area with the most persistent
rainfall through the afternoon has been from Southern Aroostook
to just south of Greenville. As this band pivots through, also
may see flash flood risk increase in this already moist surface
soil.
New wind headlines were issued to account for Elsa`s transition
into a post tropical cyclone. The main concern was a band of
stronger northerly winds wrapping around the center as it
departs to NB. NAMnest and HRRR have shown this fairly
consistently for runs today, bringing up to 40mph gusts from the
NNW into central Washington County and coastal Hancock. Given
the large amount of moisture wrapping around and into drier air
on the back side, some of these gusts may show momentum
transfer during transition. The Advisory was issued primarily
for impacts due to recent saturated soil, seasonal dry
conditions, and a quick wind shift from east to north this
evening.
Fog continues this evening as Elsa pulls away, becoming less
dense towards Sat morning. Precip will cut off after midnight as
well, with only a few remaining showers across far eastern
Maine.
&&
.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/...
High pressure will cross the region Saturday night through
early Sunday with mostly clear skies. A cold front will then
begin to approach northern Maine later Sunday afternoon with a
chance of afternoon showers/thunderstorms across northern areas,
with partly sunny skies Downeast. The cold front begins to
cross the region Sunday night, reaching Downeast areas late.
Could still have a chance of showers/thunderstorms across
northern areas Sunday evening. Otherwise, expect decreasing
shower chances with the loss of diurnal heating while the front
moves south overnight. The front will cross the Gulf of Maine
Monday then stall. High pressure will build across the region in
the wake of the front Monday with mostly/partly sunny skies.
Temperatures will be at near normal levels Sunday/Monday.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
High pressure will cross the region Monday night then begin to exit
across the Maritimes Tuesday. Expect mostly clear skies Monday night.
The stalled frontal boundary will start to move back north in the
form of a warm front with the return flow around high pressure
Tuesday. Expect increasing clouds Tuesday. Could also have the
chance of an afternoon shower/thunderstorm. The warm front crosses
the region Wednesday with a chance of showers/thunderstorms. Warm,
humid conditions are expected Thursday and Friday along with a
chance of mostly afternoon and evening showers/thunderstorms with
diurnal heating. An approaching cold front could also help support
thunderstorm chances Friday. Near normal level temperatures are
expected Tuesday/Wednesday. Slightly above normal level
temperatures are expected Thursday/Friday.
&&
.AVIATION /04Z SATURDAY THROUGH WEDNESDAY/...
NEAR TERM: VFR/MVFR from PQI to FVE will fall to MVFR with a
brief period of IFR cigs due to steady rain. MVFR at HUL will
fall to IFR this evening. All northern sites improve to MVFR by
06z with VFR by 09z. Winds light and variable becoming N 5-15kts
after 03z. Southern sites IFR/LIFR with rain and fog will
improve to MVFR cigs after 03z with improvement to VFR by 06z.
BCFG will be possible through daybreak which may cause brief IFR
conditions. E-NE winds 10-20kts early will shift N-NW 10-20kts
with some gusts to 35kts at BHB possible this evening. LLWS is
possible at BHB this evening. VFR expected all sites Saturday
with N-NW winds 5-10kts.
SHORT TERM: Saturday night...VFR. Light winds.
Sunday... Generally VFR. However, variable conditions possible
across northern areas late with any showers/thunderstorms. Southwest
winds around 10 knots.
Sunday night...Variable conditions with any showers/thunderstorms.
Otherwise, VFR. Light winds.
Monday/Monday night...VFR. Northwest/north winds around 10 knots
Monday. Variable winds 5 to 10 knots Monday night.
Tuesday...Variable conditions with any showers/thunderstorms.
Otherwise, VFR. South/southeast winds 10 to 15 knots.
Tuesday night/Wednesday..Variable conditions with any
showers/thunderstorms, also with any fog Downeast.
Otherwise, VFR. South/southeast winds 10 to 15 knots.
&&
.MARINE...
NEAR TERM: Wind gusts increase to Gale across the eastern waters
this evening and overnight. Overall, easterly winds will be
strong ahead of Elsa`s approach, lighter as circulation passes
through the waters, then increasing once again from the WNW.
Expect a few gusts up to 35 kt in the Small Craft Adv area, with
these WNW winds, but more brief than the eastern Gale.
Wave heights build this evening 7 to 10 ft with high surf along
the coast. SCA level wave heights continue through Saturday
decreasing to 3 to 4 ft.
SHORT TERM: Winds/seas below small craft advisory levels
Saturday night through Monday. Patchy fog Saturday night.
Could have a slight chance of showers later Sunday night.
&&
.HYDROLOGY...
Current forecasts still bring storm totals of 2.5 - 4.0 inches,
with locally higher expected. These totals combined with the
intense rates will cause the threat for flash flooding in the
Watch area. Upstream observations indicate conditions favorable
for flash flooding that is expected to move into the region late
this afternoon and evening.
Rivers, especially small streams, are expected to rapidly rise,
with major rvrs little flood risk due to prior low flow levels.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...High Surf Advisory until 2 PM EDT Saturday for MEZ029-030.
Wind Advisory until 3 AM EDT Saturday for MEZ017-029-030.
MARINE...Small Craft Advisory until 2 AM EDT Saturday for ANZ051-052.
Gale Warning until 2 AM EDT Saturday for ANZ050.
&&
$$
Near Term...VJN
Short Term...Norcross
Long Term...Norcross
Aviation...VJN/Norcross
Marine...VJN/Norcross
Hydrology...
Area Forecast Discussion
National Weather Service Cheyenne WY
832 PM MDT Fri Jul 9 2021
.UPDATE...
Issued at 831 PM MDT Fri Jul 9 2021
Upon coordination with the Storm Prediction Center, we have
extended the Severe Thunderstorm Watch until 11 PM.
UPDATE Issued at 738 PM MDT Fri Jul 9 2021
Grids have been updated as the Red Flag Warning will expire at
8 PM. Also adjusted the thunderstorm chances for the rest of the
evening.
&&
.SHORT TERM...(This evening through Saturday)
Issued at 148 PM MDT Fri Jul 9 2021
Current radar imagery indicates storms developing east of the
Laramie Range, with pea size hail reported and heavy rain. Both
HiRes models have been fairly consistent with the overall
convection development and storm motion, with the HRRR being
highly favored in the forecast update. Will likely see a severe
weather watch put in place over the next hour. Strong to severe
storms are possible through midnight tonight, with the 1833z Ft
Collins sounding indicating good directional shear, 2700 J/kg of
CAPE, and 49kt of 0-6 shear. Main threats today include strong
supercell storms producing large hail, flash flooding, and strong
winds. However, cannot rule out a tornado or two with a favorable
environments. Main changes from the early morning forecast has the
second wave of convection looking much less impressive. Will need
to monitor through the night to determine any additional watches
needed after 9pm MDT. As we move into the early morning hours
tomorrow, a cold frontal boundary is expected to continue digging
towards the south. Showers and Thunderstorms are possible to
continue through the early morning hours, primarily east of I-25.
Otherwise, Saturday will cool down to the high 70s to low 80s
behind the cold front, with some gusty winds around 20 to 25
knots, and precipitation chances significantly dwindling.
.LONG TERM...(Sunday through Thursday)
Issued at 411 AM MDT Fri Jul 9 2021
Key Messages:
1) Sunday will be the start of a brief warming trend into Monday
with above normal temperatures and elevated fire weather conditions
these two days.
2) Temperatures will drop back a few degrees Tuesday thru Friday
with increased afternoon shower/storm chances. Pattern favors
chances of at least isolated strong to severe storms during this
period so stay tuned next week.
Weather Discussion: Following the brief cool down Saturday as the
closed H5 low departs east, shortwave ridging will shift east across
WY in its wake Sunday and Monday. Sunday will likely be the driest
of the week as 0.3" to 0.6" PWATs range west to east under subsident
dynamics. Monday will be the warmest of the period as H7
temperatures range from +14C east to +20C west. Mid to upper 90s are
likely in the lower elevations of the High Plains and NE Panhandle,
with low 90s elsewhere. Winds will be light through the atmospheric
column overall and should preclude the need for fire headlines.
However, minimum relative humidity vales will fall into the teens
Sunday and moreso Monday for elevated to near-critical fire weather.
By Tuesday, a shortwave trough is advertised to come ashore and
swing across the Pacific NW to Montana mid-week. H5 pattern will
flatten in-between the trough north to the lower amplitude ridge
south - allowing embedded impulses to traverse the region for local
lift enhancement. Tuesday - Friday looks to be an active period of
diurnal showers/storms. Nuances of timing and available moisture
plus resultant instability will need to be monitored for strong to
severe storm potential. Likely Marginal severe risk categories
through much of next week with possibly of a few Slight Risk days.
Stay tuned through next week on day to day hazards and timing.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 521 PM MDT Fri Jul 9 2021
Wyoming TAFS...VFR at Rawlins and Laramie. Wind gusts to 48 knots
at Rawlins, and 33 knots at Laramie, until 02Z.
VFR at Cheyenne until 06Z, then MVFR until 13Z, then VFR.
Thunderstorms in the vicinity until 02Z. Wind gusts to 25 knots
from 02Z to 06Z, and to 22 knots after 13Z Saturday.
Nebraska TAFS...VFR, with occasional MVFR in thunderstorms
producing wind gusts to 45 knots until 06Z. Thunderstorms in the
vicinity from 06Z to 14Z. Wind gusts to 26 knots until 06Z, then
to 25 knots after 15Z Saturday.
&&
.FIRE WEATHER...
Issued at 148 PM MDT Fri Jul 9 2021
Above normal temperatures recorded today with humidities in the
low teens across Carbon and Albany counties and westerly winds
gusting to 35 MPH ahead of a frontal passage. Some shower and
thunderstorm activity possible with the frontal passage, which
will ease fire weather concerns as we go into the evening.
Saturday will be the coolest day with higher humidity and weaker
winds, but that relief is short-lived as temperatures warm back
up to well above normal with humidity dropping to 12 to 20% Sunday
into early next week. Looking at next week, Monday, Thursday, and
Friday appear to be the days wit elevated to near- critical fire
weather conditions with humidity below 15% and winds gusting near
25 MPH for Carbon and Albany counties. As a few shortwaves pass
through the region, afternoon thunderstorms are possible Tuesday
through Thursday, especially for far eastern Wyoming and the
Nebraska panhandle. Any fire weather headlines will be evaluated
closer to the dates.
&&
.HYDROLOGY...
Issued at 148 PM MDT Fri Jul 9 2021
Flash Flood potential on the Mullen burn scar through next Monday
will be be none to limited. Risks will increase next Tuesday
through Friday as more showers and storms become possible across
the mountains. Storms today will be too far east and then after a
cooler drier day Saturday, warm and dry conditions occur Sunday
and Monday. Additional disturbances will occur Tuesday and beyond
to support more activity and higher moisture content.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...None.
NE...None.
&&
$$
UPDATE...RUBIN
SHORT TERM...MD
LONG TERM...JSA
AVIATION...RUBIN
FIRE WEATHER...JSA/MD
HYDROLOGY...JSA
Area Forecast Discussion
National Weather Service Des Moines IA
721 PM CDT Fri Jul 9 2021
.DISCUSSION.../Tonight through Friday/
Issued at 353 PM CDT Fri Jul 9 2021
Forecast Highlights
-Severe storms and heavy rain possible tonight
-Cool and rainy weather over the weekend into Monday
Tonight into Saturday morning...Outflow boundary from large
supercell earlier today has drifted into western and southwest
parts of the forecast area and remains clearly evident via visible
satellite and base reflectivity. This could become a trigger
mechanism for additional convection later this afternoon and
evening. The atmosphere is certainly primed for additional severe
weather across the western and southern portions of the forecast
area. Surface based CAPE has increased to around 5000 J/kg in
southwest Iowa with the gradient setting up from around Denison
southeast to Lamoni. Cap has eroded with 700mb temp around 10C and
fairly steep lapse rates have developed over the west. Shear is
strong, 0-6km shear around 50 knots and effective shear even
higher. Low level shear, at least the 0-1km shear, is only around
10 knots but latest HRRR and RAP soundings suggest a bit higher
later this afternoon and evening. The Bunkers right-moving
supercell motion is southeast and if any storms initiate along the
aforementioned outflow boundary, they should follow this motion
which lines up well with the instability gradient. Challenging to
believe any of the hires models as they did not perform well with
the large hail producer today. Nonetheless, the latest NAMNest
does suggest development along the outflow boundary by around 00z
and confidence is increasing this scenario will pan out. Timing
might be a bit later for redevelopment, but agree with the
location in the vicinity of the outflow. Storm mode is likely
supercell with initiation with hail and damaging wind and possibly
tornado or two with the amount of low level helicity and
effective helicity. Expect storms to quickly combine and develop
into a more of a bowing segment as it moves southeast into
Missouri.
Another round of storms is possible with a strong shortwave
causing convection over the high plains of Nebraska and this
convection looks to reach the CWA by the overnight hours towards
Saturday morning. Low confidence this MCS holds together and/or
remains severe as it depends how favorable the atmosphere in
southwest Iowa is going be after the potential convection in the
same location this evening. Certainly heavy rain is a threat with
PW as high as 2.00 to 2.25 inches across the south and decent
moisture transport into the state. Given the uncertainty if the
MCS will roll into southern Iowa or northern Missouri, kept the
Flash Flood Watch confined to the southeast for now.
Saturday into Monday...the surface and upper level low pressure
stalls over the region into Monday providing additional rain
chances and cooler weather through the weekend. Severe weather
potential remains low with the lack of significant instability
over the weekend.
Tuesday through Friday...the upper low finally gets kicked
eastward with the upper level ridge over the southwest expanding
east. A cold front and strong upper level low looks to push
thorugh the region Wednesday night into Thursday.
&&
.AVIATION.../For the 00Z TAFS through 00Z Saturday evening/
Issued at 720 PM CDT Fri Jul 9 2021
Primary concern for TAFs this cycle was trying to time overnight
convection. While severe thunderstorm potential continues for the
next few hours, confidence is highest in greatest thunderstorm
coverage occurring in the 03-12z timeframe across central and
southern Iowa. Any severe weather threat this evening will
transition to flooding concerns overnight. Coverage will be less
at KFOD, KMCW, KALO, and better at KDSM and KALO. Convection
lingers but gradually decreases in coverage during the day on
Saturday.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...
Flash Flood Watch through Saturday morning for IAZ085-086-
095>097.
&&
$$
DISCUSSION...Podrazik
AVIATION...Hahn
Area Forecast Discussion
National Weather Service Grand Forks ND
649 PM CDT Fri Jul 9 2021
.UPDATE...
Issued at 649 PM CDT Fri Jul 9 2021
Surface high pressure is holding over the western Great Lakes
while a low pressure system is expected to scoop just south of
the tri-state area... through eastern NE, through the overnight
period into Saturday morning. Deep convection which earlier
tracked through western and central ND, should dissipate in
northeast SD according to recent HRRR guidance, though various
CAMS keep some convection into the far southern RRV and adjacent
portions of westcentral MN into early evening. An updated
Aviation Discussion is attached below.
&&
.SHORT TERM...(This evening through Saturday night)
Issued at 259 PM CDT Fri Jul 9 2021
Any rain chances in our western counties tonight then temperatures
will be the main issues for the period.
Several weak shortwave troughs continue to dig through the region,
mostly following a central ND to SD/MN track. There continues to
be some shower activity in south central ND thanks to one of the
weak shortwaves, although with MU CAPE values of 500 J/kg at best
the strength of the convection has remained fairly weak. CAMs have
the showers and thunderstorms over central ND slowly moving
southeastward this evening, clipping some of our western counties.
Most recent radar loop seems to be trending more towards the drier
HRRR rather than some of the wetter CAMs. However, can`t
completely rule out a bit of rain moving into our west, so kept
some 20-50 POPs going.
The main shortwave digging down through SD tonight will strengthen
and cut off to our southeast Saturday into Saturday night. Weak
surface high pressure and dry conditions will set in by afternoon
as the system pulls further away from our CWA. Temps will be a bit
warmer and more firmly in the 80s with more sunshine on Saturday.
.LONG TERM...(Sunday through Friday)
Issued at 259 PM CDT Fri Jul 9 2021
Widespread hazardous weather in the long term period is currently
not expected. That being said, there is a chance for perhaps some
thunderstorms around the Monday-Tuesday timeframe with an assoc cold
fropa, as well as a greater than 30 percent chance for temperatures
above 90 degrees.
Upper ridging will build into the region from the west Sunday
allowing temperatures to near and break 90 for most. After Sunday,
heights decrease as a trough moves through Canada with perhaps a
smaller system moving through the Central Plains into the Upper
Midwest. This trough pushes a cold front or inverted surface trough
through the Dakotas into the Upper Midwest around Monday and
Tuesday. This forcing mechanism should allow for some convection.
There isn`t a great signal for very robust convection at this time
due to an expected lack of appreciable instability and generally
weak forcing/kinematic regime aloft. This may change some as time
nears, but current guidance suggests convection to remain on the
weaker side.
Getting into mid to late next week, heights will be back on the rise
as a ridge is anticipated to again build over the intermountain
West. This increases chances for near or above 90 degree temps late
in the week. This is depicted nicely in ensemble means and NBM
probabilities. This increase in heat content and chance to be on the
periphery of the upper ridge may bring chances for storms back into
the forecast late next week, although details remain far from clear
at this time.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 649 PM CDT Fri Jul 9 2021
Expect VFR and light winds across the FA, throughout the forecast
period. Generally fair skies with light and variable winds will
extend from northeast ND, across the Red River corridor, and
across all of northwest MN. Areas of mid level cigs and southeast
winds to 10kts are mainly along and west of a RUG-BAC-BWP line,
and will steadily shift southward and eventually out of southeast
ND through 10z.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...None.
MN...None.
$$
UPDATE...Gust
SHORT TERM...JR
LONG TERM...CJ
AVIATION...Gust
Area Forecast Discussion
National Weather Service Flagstaff AZ
146 PM MST Fri Jul 9 2021
.SYNOPSIS...High pressure remains in control through the weekend,
delivering hot daytime temperatures through Sunday. A slight
increase in monsoonal moisture will take place over the weekend,
however showers and storms are expected to remain isolated to the
Mogollon Rim. More significant moisture looks to return next week,
with greater chances for showers and thunderstorms.
&&
.DISCUSSION...Scattered showers and thunderstorms have develop
across the the Mogollon Rim, Chuska Mountains and Black Mesa this
afternoon. Activity over the far northeast is expected to diminish
within the next few hours. Latest HRRR guidance has activity over
the Mogollon Rim increasing over the next couple of hours, with a
line of thunderstorms moving off the Rim into this evening. Much
of the activity should diminish around 8pm, with only a few light
showers and storms remaining through 10pm over southern Yavapai
and Gila counties. Primary threats will be strong gusty outflow
winds and brief heavy rainfall, a few of the stronger storms also
have the potential to produce some small hail.
The strong ridge over the southwest will remain in place through
the weekend, with heights maximize over northern Arizona on
Saturday. As a result, hot temperatures are expected to continue
over the area, with Saturday being the warmest day. Excessive Heat
Warnings remain in effect for the lower elevations of Yavapai
County as well as the Grand Canyon. Much of the showers and
thunderstorm activity this weekend will be suppressed with the
stable air mass in place, however slight chance for showers and
storms will exist along the Mogollon Rim and higher terrain during
the afternoon hours.
For the start of next week, the ridge begins to degrade and wobble
around the southwestern United States. Monsoonal moisture beings
to surge northward into Arizona, bringing the chance for more
widespread showers and thunderstorms for much of the upcoming
week. Much of the EPS members, and to a lesser extent the GEFS
members, are in agreement with an increase in moisture into
northern Arizona. Cooler, more seasonable temperatures and light
winds are also expected for next week.
&&
.AVIATION...For the 00Z package...VFR conditions are expected to
prevail for much of the period. Local MVFR conditions will be
possible in showers and thunderstorms mainly along and south of a
KGCN-KFLG-KSOW line. More isolated showers and storms will be
possible after 20Z Saturday. Gusty and erratic winds will be
possible in and around thunderstorms. Aviation discussion not
updated for TAF amendments.
&&
.FIRE WEATHER...Isolated showers and thunderstorms are expected
Saturday and Sunday, mainly along the Mogollon Rim and
south. Primary hazards will be strong gusty outflow winds, brief
heavy rainfall, and lightning. Temperatures are expected to remain
hot along with light northwest/north winds.
Monday through Wednesday...Shower and thunderstorms chances
increase each afternoon areawide for the start of next week.
Cooler more seasonable temperatures and light winds are also
expected.
&&
.FGZ WATCHES/WARNINGS/ADVISORIES...
Excessive Heat Warning until 8 PM MST Saturday FOR AZZ037.
Excessive Heat Warning until 8 PM MST Sunday FOR AZZ005-006.
&&
$$
PUBLIC...Humphreys
AVIATION...Humphreys
FIRE WEATHER...Humphreys
For Northern Arizona weather information visit
weather.gov/flagstaff
AREA FORECAST DISCUSSION
National Weather Service Hastings NE
625 PM CDT Fri Jul 9 2021
.DISCUSSION...(This evening through Friday)
Issued at 500 PM CDT Fri Jul 9 2021
Main forecast concern is the potential for severe thunderstorms
tonight and Saturday and ongoing hot/humid conditions.
Uncomfortably hot and humid conditions have come to fruition this
afternoon across the entire area, with some areas even climbing
into the dangerously hot and humid range with heat indices near
105F. The highest HI`s are across north central KS, but even some
areas further N from GRI to JYR are near 105F, owing to weaker
mixing and strong evapotranspiration. One could argue conditions
are actually worse along I-80 than north central KS due to much
lighter wind speeds. Luckily, though, this is a one day ordeal, as
much cooler conditions arrive behind a cold front tonight. The
ongoing Heat Advisory is on track to expire at 01Z this eve.
Severe thunderstorms are forecast to become an increasingly
greater concern by mid to late evening and continue into the
overnight. Will start by saying the overall severe threat has
seemingly increased compared to 24 hrs ago, and there is some
concern that at least portions of the CWA could see significantly
high wind gusts of 70+ MPH. The main change from last couple of
forecasts is that instability has trended higher, and further W.
For example, HRRR MLCAPE for the LXN area at 00Z this eve has
trended from 2000-2500 J/kg on yesterday`s 12Z and 18Z HRRR, to
over 3500 J/kg on latest HRRR runs. This seems reasonable given
Tds that have held firm in the low 70s, even around LXN where
models progged Tds to fall into the low 60s by aftn. The higher
instability values also extend further W into central and western
Neb. This should make it easier for activity in the W Panhandle
now to organize into a forward propagating MCS and maintain it`s
intensity as it moves E thru the late eve and overnight. Shear is
not lacking, and is actually quite impressive for July as a
50-60kt H5 speed max overspreads the instability axis. Magnitude
of instability and shear now argue for a decent potential of sig
severe, but this will also depend on how convective activity
evolves W of here this eve. HRRR and NAMNest simulated
reflectivity and sfc wind gust output have suggested a trend
towards a more organized event, and more linear, which are usually
good signals for at least localized significant wind gusts. Don`t
want to discount the hail potential, either, but this will
largely depend on storm mode. Some embedded supercells within a
broader line are certainly possible. Also, forecast 0-3km shear
vector magnitude and orientation, along with rich low level
moisture, suggest some brief QLCS spin-ups can`t be ruled out
either. Quick storm motions are expected, which should keep the
heavy rain potential fairly low. One area to watch would be from
Ord to Geneva as these areas received rainfall last night, but
overall, most of the area has been dry of late. A more likely
hydro scenario would be short- lived urban issues due to brief but
torrential downpours. Model MUCAPE progs suggest the first round
will scour much of the area of its instability prior to 06Z, but
just enough CAPE may linger to combine with additional vort lobes,
continued strong effective deep layer shear, and lowering
freezing levels to keep a hail threat going a few hrs longer.
Saturday continues to look like a messy day with off and on
scattered tstms possible pretty much everywhere and at any time as
several vort lobes rotate into the deepening trough over IA/MO.
Much cooler mid level temps will essentially leave the entire area
uncapped to any sort of sfc heating, so may see an uptick on
convective coverage/intensity as early as 16Z to 18Z. 1-2K J/kg
of CAPE and 25-30kt of deep layer shear may be enough to support
some iso pulse-type marginally severe tstms (nickel-quarter size
hail) given seasonably low WBZ levels, esp across roughly S half
of CWA. Lgtn and hvy downpours (PWATs linger near 1.5" and tall,
skinny CAPE) will likely be greatest concern for those with
outdoor plans. Expect decr coverage/intensity thru the eve as
daytime heating fades. Highs will be much cooler and range from
mid 70s N, to mid 80s S.
Sunday continues to look like the best day of the weekend. Models
are still a bit mixed with regards to position of upper low and
thus how far W moisture will wrap around. Have some slgt chc PoPs
lingering over E third of CWA thru the AM, and may need to extend
into PM hrs if trends from 15Z RAP and 18Z GFS continue, but
NAM and EC are drier. Regardless, overall pcpn chcs are much lower
Sun compared to Sat and Sun will still be pleasant with highs in
the 70s/80s and low humidity. Wind will start off the day on the
breezy side (so may even be a bit chilly in the AM), then
gradually decline thru the aftn and esp eve.
Little time spend on the extended periods. Mon and Tue are still
mainly dry with highs climbing from the 80s into the 90s. Pattern
may turn unsettled for middle to later portions of next week, but
confidence on details are low attm.
&&
.AVIATION...(For the 00Z KGRI/KEAR TAFS through 00Z Sunday)
Issued at 619 PM CDT Fri Jul 9 2021
Main forecast concern for this period will come mid-late evening,
as thunderstorm activity is expected to be pushing in from the
WNW. Still some uncertainties with the exact timing, have the
strongest winds coming through between 04-06Z. Currently have a
tempo group with 45KT gusts at both places, but higher gusts
certainly not out of the question. Through the rest of the
overnight hours and into Saturday, plenty of uncertainties remain,
as the potential for at least scattered showers and thunderstorms
continues. Felt that the early-mid morning and mid-late afternoon
hours had the better chances for precip, so kept a VCTS mention
going during those times. Otherwise, once the main push of storms
comes through later this evening, have winds NWrly in nature, but
confidence in just how winds evolve is not high.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...Heat Advisory until 8 PM CDT this evening for KSZ005>007-017>019.
&&
$$
DISCUSSION...Thies
AVIATION...ADP
Area Forecast Discussion
National Weather Service Gray ME
1048 PM EDT Fri Jul 9 2021
.SYNOPSIS...
Tropical Storm Elsa will cross the Gulf of ME today. Very heavy
rain is still possible across the region with potential for flash
flooding, especially in areas along and just inland of the
coast. Some gusty winds are possible along the coast along with
large breaking waves. The remnants of the tropical storm will
depart the region tonight with seasonable temperatures and dry
weather expected this weekend.
&&
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
1030 PM Update...
Significant updates to the forecast were made earlier this
evening with package update. The steady, heavy rain associated
with Post Tropical Cyclone Elsa has shifted out of the region
per latest radar imagery. In its wake, scattered showers will
continue to develop. The precipitation over northern areas has
diminished, while showers continue near the Massachusetts state
line, similar to the latest HRRR.
Over 4 inches of rain fell in a few spots today, mainly along
and near the coastline. The significant rainfall totals will
allow local tributaries to remain high throughout the night
despite the dry antecedent conditions.
Made minor tweaks to temperature, dew point and wind forecasts
in the near term portion of the forecast. Patchy to areas of fog
may develop during the night per the latest HREF ensemble mean with
plenty of low level moisture remaining in place.
Update...
Have updated the forecast to remove the flood watches from western
portions of the forecast area.
Prev Disc...
Elsa will accelerate northeastward through the Gulf of Maine
this evening with the back edge of the rain soon to clear east
of New Hampshire. Moderate to heavy rain will continue south of
the mountains in Maine with a focus along the Mid- Coast. Here
expect rainfall rates around 1 inch per hour through about 7 PM.
The back edge of the rain will clear Maine zones from west to
east and should be east of the area before sunset. Latest
satellite imagery shows some clearing skies over upstate New
York with partial clearing expected across southern New
Hampshire early this evening with some clearing over southern
Maine late this evening. Mesoscale guidance suggest there will
be burst of north to northwest winds behind Elsa`s remnants with
gusts to 20 mph this evening.
Mid level trough axis will still be to our west through the first
part of tonight. Partial clearing over upstate New York has
allowed the atmosphere to destabilize leading to scattered
convection. Latest RAP analysis suggests that partial clearing
into New Hampshire this evening with lead to about 500 J/kg of
SBCAPE to develop before sunset. This will bring slight chances
for scattered convective showers to develop in the wake of Elsa.
Latest mesoscale guidance suggests that these showers or
thundershowers will be weak and short lived, but cannot rule out
additional precipitation chances across the area through late
this evening after Elsa has cleared the area.
Later tonight some decaying convection is expected to track across
southern New England possibly scraping along southern areas. Have
kept slight chances for showers here overnight and early Saturday
morning along with areas of patchy fog across much of the area
tonight. Lows tonight will range from the mid 50s north to mid 60s
south.
&&
.SHORT TERM /6 AM SATURDAY MORNING THROUGH SATURDAY NIGHT/...
High pressure builds into the area Saturday while cyclonic flow
remains aloft. A mostly dry day is expected, although cyclonic flow
aloft may lead to a stray afternoon shower. Skies will be partly to
mostly sunny with highs in the 70s. High pressure continues to build
over the area Saturday night for mostly clear skies and lows into
the 50s to near 60F across southern New Hampshire.
&&
.LONG TERM /SUNDAY THROUGH FRIDAY/...
The East Coast upper level ridge begins to reestablish itself rather
quickly to start out the extended forecast. The Euro ensemble mean
continues to show rapid height rises at H5 on Sunday along and off
the Eastern Seaboard. Meanwhile, a long wave trough will approach
from the Plain States which will be blocked and cutoff by early next
week. Some moisture will attempt to rotate around the periphery of
the upper level ridge, allowing for a chance for showers in our
region. This will mainly be over southern section of the forecast
area.
By Tuesday, 12Z guidance suggests the closed low will begin to open
up and move east. This will allow for scattered showers across New
Hampshire and western Maine. Sufficient instability may allow for a
few thunderstorms as well.
This wet pattern will continue late in the work week as another
trough crosses the forecast area.
&&
.AVIATION /02Z SATURDAY THROUGH WEDNESDAY/...
Short Term...VFR conditions at KHIE and KLEB are expected to
drop to IFR tonight in lowering cigs and reduced vsby in BR or
fog. IFR conditions at KCON and KMHT may briefly improve to VFR
this evening before dropping to IFR overnight in lower cigs and
reduced vsby in BR or fog. IFR/LIFR conditions are expected to
continue overnight at remaining terminals. Conditions improve to
VFR at all terminals Saturday morning and lasts through
Saturday night.
Long Term...Ceilings begin to lower Sunday into Monday over
southern sections, namely southernmost New Hampshire in close
proximity to a warm front. Some IFR conditions will develop in
showers and any scattered thunderstorms mainly during the
afternoon and evening hours Tuesday and Wednesday. Patchy fog
will locally lower visibilities during the night as moisture
levels will remain high.
Mostly VFR conditions on Thursday or Friday. However, there may
be an afternoon thunderstorm as well during this period.
&&
.MARINE...
Short Term...SCAs have been extended for the outer waters for
most of the day on Saturday mainly due to high seas.
Long Term...Both winds and seas will remain below SCA thresholds
through the period.
&&
.HYDROLOGY...
The steady, heavy precipitation has shifted east of our region.
Will continue to monitor some of the smaller tributaries across
the region as water levels will remain high. Drier air enters
the region overnight and on Saturday.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...High Surf Advisory until 11 AM EDT Saturday for MEZ023>028.
NH...High Surf Advisory until 11 AM EDT Saturday for NHZ014.
MARINE...Small Craft Advisory until 5 PM EDT Saturday for ANZ150-152-
154.
&&
$$
NEAR/SHORT AND LONG TERM...Cannon
Area Forecast Discussion
National Weather Service North Platte NE
629 PM CDT Fri Jul 9 2021
.SHORT TERM...(This evening through Saturday night)
Issued at 321 PM CDT Fri Jul 9 2021
Obvious trigger for severe storm development is moving through WY
this afternoon. Storm activity is firing on the Laramie Range and
moving east and southeast. The Bunkers storm motion in the NAM and
RAP models backed by the HRRR and NAMdng models suggests a southeast
storm motion toward Interstate 80. Meanwhile, the model consensus
however suggested activity would develop on the Pine Ridge and move
through the Sandhills. This could still happen given the developing
cumulus field in that area.
Given the very strong shear, 0-6km and 0-8km of 50 kts to 75 kts,
very large hail is the concern where ever storms develop. The NAM
soundings also show a pocket of dry air forming in the low to
midlevels of the atmosphere which would support strong winds,
perhaps coincident with the hail. Such was the case across wrn SD
Thursday evening with an isolated storm which produced 2"+ hail and
60 to 70 mph winds.
The very strong shear which results in Bulk Richardson number of 50
or less across wrn Nebraska could limit the severe storm coverage to
isolated coverage with one or two discrete storms, but this is
difficult to predict. The severe weather parameters, including an
increase in CAPE, suggest upscale growth near and east of highway
83 this evening.
SPC suggested a 2 percent tornado risk across wrn Nebraska and
this is based on a very modest warm sector opening up across the
Cheyenne divide and perhaps parts of the Pine Ridge as suggested
the RAP model. The low level vorticity along the warm front
combined with stretching caused by daytime heating could
potentially support tornado development.
There is also the prospect of a second or third round of thunderstorms
developing late this evening and overnight before all of the
storms exit east by 12z Saturday. A check on the elevated
instability in the NAM and RAP soundings, suggests the potential
for a few additional severe storms capable of large hail. The
elevated CAPE in these models varies from over 3000 J/KG in the
RAP to less than 2000 J/KG in the NAM. This instability and the
very strong shear is concerning. Thus, the potential for early
evening severe weather is obvious but the prospect of overnight
severe weather is uncertain.
The models are in very good agreement forming a cut-off low across
Iowa Saturday. The NAM shows elevated instability along and east of
highway 83; around 1000 J/KG of CAPE which should support
thunderstorms with the potential for small-subsevere hail. The loss
of daytime heating Saturday evening should cause most of the this
rain activity to dissipate.
The thunderstorm forecast tonight uses the short term model blend
plus the HRRR and NAMdng. This forecast attempts to drive the
thunderstorm chances south toward and south of Interstate 80 as
suggested by the HRRR and NAMdng. The short term model blend is
farther north across the Sandhills. The short term model blend was
the basis for the shower and thunderstorm chances across ncntl
Nebraska Saturday. This rain is associated with cold air aloft
from the developing upper level low across Iowa.
.LONG TERM...(Sunday through Friday)
Issued at 321 PM CDT Fri Jul 9 2021
The next chance for organized thunderstorms development appears
to be Tuesday night but the models have slowed the arrival of an
upper level disturbance moving through the nrn Plains by perhaps 6
hours. This disturbance would present the best thunderstorm
chances Tuesday evening and overnight across SD and nrn Nebraska.
Winds aloft at h500mb-300mb increase to 30 to 50kts, dew points
rise into the lower 60s and the GFS suggested precipitable water
around 1 inch ahead of the storms. Chance POPs are in place for
this system with the best rain chance across nrn Nebraska.
Otherwise, the forecast is dry except for isolated thunderstorm
chances.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 629 PM CDT Fri Jul 9 2021
The main weather concern over the next day will be the potential for
thunderstorms across all of western and north central Nebraska.
Thunderstorm development is currently ongoing across the Panhandle
and will track south and east over the remainder of the evening and
overnight. Some of these storms will have the potential for very
large hail, damaging winds, and locally heavy rainfall. Visibility
restrictions will likely occur at both sites this evening. Rain
showers will continue into Saturday morning with some patchy fog as
well. Additional restrictions down to 4 miles may be possible due to
fog. Conditions will slowly improve by Saturday afternoon returning
to VFR at KLBF by late afternoon. Ceilings remain near 4000 feet at
KVTN through the afternoon.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SHORT TERM...CDC
LONG TERM...CDC
AVIATION...Kulik
Area Forecast Discussion...Updated
National Weather Service Saint Louis MO
1057 PM CDT Fri Jul 9 2021
.UPDATE...
Issued at 1057 PM CDT Fri Jul 9 2021
Although severe thunderstorms have been the primary concern so far
this evening, this threat will be joined by/transition to flash
flooding overnight into Saturday morning. Recent convective trends
suggest that, in addition to the current Flash Flood Watch area,
flash flooding will be possible in central MO as back building and
training of thunderstorms becomes increasingly likely along the
western flank of the MCS currently surging southward across the CWA.
There is also potential for the maturing upstream MCS across eastern
NE to traverse this area Saturday morning. As such, the Flash Flood
Watch has been expanded to include portions of central MO and has
been extended in time until 18z Saturday.
Pfahler
&&
.SHORT TERM... (Through Late Saturday Night)
Issued at 354 PM CDT Fri Jul 9 2021
The synoptic setup this evening reminds me a bit of July 19, 2006 or
June 28, 2018...although there are differences which may mitigate
some of the worst of those two events. First, while there is a lot
of CAPE available for convection to feed on this evening (2000-3500
J/Kg) MUCAPE, there isn`t as much as was available on either of the
other cases. Second, I believe the 0-3km and 0-6km shear values
were stronger in both of the previous cases. All that being said,
I don`t think the MCS tonight will be as strong as in the older
cases, but there still certainly a threat for winds of 60-70 mph,
large hail, and a few tornadoes with the 0-1km shear rising to
around 20-25kts after 04Z. There remains some question on timing and
the exact track of the MCS. The most likely scenario is that storms
over Iowa will strengthen as the low level jet strengthens this
evening. Discrete convection should congeal into an MCS as the
storms interact with one another, and the resulting MCS will dive
southeast, paralleling the Mississippi River. In fact, the outflow
boundary left from the supercell that went through Des Moines
earlier may be where storms initiate on the low level jet. With that
in mind, the most likely timing for severe convection will be from
late evening into the early overnight hours...maybe 02Z to 08Z. The
severe threat will likely transition to a flash flood threat after
06-08Z. WPC QPF shows 2+ inches of rainfall across parts of
northeast Missouri and west central Illinois through Saturday
morning, and there will almost certainly be higher amounts in
locations that get more than one heavy thunderstorm.
Saturday`s convection will depend heavily on what ultimately happens
tonight. Present indications are that after tonight`s MCS exits the
region, there will be enough diurnal heating and destabilization for
another round of severe thunderstorms...mainly along and south of I-
70 during the afternoon and evening. Deep layer shear isn`t that
impressive at 25-30kts, but RAP forecast SBCAPE values climb back up
above 3000 J/Kg over southeast Missouri Saturday afternoon. The
initial round of thunderstorms on Saturday afternoon/evening will
likely stabilize the atmosphere enough to limit the severe threat,
but showers and storms will likely continue overnight as a strong
upstream shortwave dips into the lower Missouri Valley and cuts off
over northwest Missouri.
Carney
.LONG TERM... (Sunday through Next Friday)
Issued at 354 PM CDT Fri Jul 9 2021
Briefly for Sunday through next Friday...
Medium range guidance shows the cut off low over northwest Missouri
spinning in place until Monday when it begins opening up and
drifting east-northeast. Scattered showers and thunderstorms will
likely continue across the area at least through Monday while this
low is in the vicinity. Temperatures Sunday and Monday are
expected to be below normal with highs struggling to reach the mid
70s to low 80s across most of the area.
The pattern becomes more zonal by late Tuesday in the wake of the
low with a weak upper level trough developing over the Midwest by
late Wednesday. This pattern will keep unsettled weather and a
chance for thunderstorms each day through the end of the period.
Temperatures should also warm back up toward seasonal normals as the
pattern becomes zonal by late Tuesday.
Carney
&&
.AVIATION... (For the 00z TAFs through 00z Saturday Evening)
Issued at 658 PM CDT Fri Jul 9 2021
Thunderstorms remain the primary concern through this TAF period,
with their evolution and resulting timing still considerably
uncertain. Latest expectation is for thunderstorms to develop across
IA and northern MO this evening and move southeastward near the
Mississippi River overnight into early Saturday morning, leading to
greatest chance of impacts at KUIN and St. Louis metro terminals.
These impacts include heavy rainfall reducing visibilities and
strong wind gusts. Timing of these thunderstorms will likely need to
be fine tuned by amendments as convective evolution becomes more
clear over the next few hours.
Showers, possibly a thunderstorm, could linger into Saturday morning
along with formation of MVFR stratus over all terminals for at least
a period during the morning. The southern edge of stratus will
likely erode by afternoon with improvement to VFR flight conditions
anticipated at KCOU, KJEF, and St. Louis metro terminals. Showers
and thunderstorms are expected to redevelop Saturday afternoon, with
the lowest chances of precipitation at KUIN reflected by only
mention of VCSH at this juncture.
Pfahler
&&
.PRELIMINARY POINT TEMPS/POPS...
Saint Louis 70 83 69 82 / 80 90 90 70
Quincy 68 77 66 75 / 80 80 80 70
Columbia 71 82 66 76 / 70 80 80 60
Jefferson City 72 84 68 78 / 50 80 90 60
Salem 67 84 69 83 / 60 90 90 80
Farmington 69 86 66 83 / 50 90 90 70
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...Flash Flood Watch through Saturday afternoon for Audrain MO-
Boone MO-Callaway MO-Cole MO-Gasconade MO-Knox MO-Lewis MO-
Lincoln MO-Marion MO-Moniteau MO-Monroe MO-Montgomery MO-
Osage MO-Pike MO-Ralls MO-Shelby MO-Warren MO.
IL...Flash Flood Watch through Saturday afternoon for Adams IL-Brown
IL-Pike IL.
&&
$$
WFO LSX
Area Forecast Discussion
National Weather Service Memphis TN
935 PM CDT Fri Jul 9 2021
.UPDATE...
Convection continues to die off in the region due to the loss of
daytime heating. Don`t expect much coverage during the overnight
period, but will continue to keep an eye on convection that is
occurring across Northern Missouri. Latest HRRR shows this
convection staying to the north of the Mid-South through the
remainder of the night. Will keep chance POPS near the AR/MO and
KY/TN state borders in case the convection gets further south than
anticipated. Made some minor temperature and sky conditions tweaks
as well.
KRM
&&
.DISCUSSION... /issued 256 PM CDT Fri Jul 9 2021/
Thunderstorms with heavy rainfall dot the area this afternoon
most numerous near a weak surface boundary. These storms are
expected to continue with localized flash flooding possible into
the evening hours.
Looking for convection to wane for Saturday before an upper low
moves into the center of the country. This feature will force more
numerous storms across the region Saturday night and Sunday. Our
forecast area is outlooked for excessive rainfall and severe
weather over this time period. A flash flood watch may be needed.
Later forecasts will better address the time and location of the
heaviest rainfall potential and the need for a watch.
The upper low lifts out by mid-week, leading to a progressive
westerly flow across the northern tier of the US. Temperatures will
rebound while the threat for diurnal storms continues.
Temperatures due to the convection are tricky. Max temperature
readings under the upper low will hold in the 80s Sunday into
early next week.
Belles
&&
.AVIATION...
SHRAs/TSRAs have lifted north. Leftover light rain invof KMEM
is quickly dissipating. Expect VFR conds overnight. Could see
some SHRAs develop as the LLJ increases later tonight but
confidence is low. SW winds will increase Sat AM to 10-14 kts with
higher gusts...mainly across the Delta. Expect scattered
SHRAs/TSRAs to develop with surface heating by Sat aftn.
SJM
&&
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...None.
MO...None.
MS...None.
TN...None.
&&
$$
Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
655 PM CDT Fri Jul 9 2021
.UPDATE...
Issued at 655 PM CDT Fri Jul 9 2021
Precip in south central MN diminished quickly during the late
afternoon, but the next round looks to be developing in northeastern
SD and southeastern ND now. This should clip west central into south
central MN late tonight into Saturday morning, with other potential
for some development as well.
Also updated for aviation discussion below.
&&
.SHORT TERM...(This evening through Saturday night)
Issued at 323 PM CDT Fri Jul 9 2021
A fairly robust line of showers and thunderstorms oriented northwest
to southeast across south central MN is being supported by modest
moisture advection/convergence and an elongated ribbon of vorticity
across the Upper Midwest. Radar estimates 2 to 3 inches have fallen
in some locations south and west of Mankato and there could be some
minor flooding during the next couple hours. The intensity seems to
be waning somewhat, so no Flash Flood Watches are being issued. This
area of convection will slide to the southeast through the rest of
the afternoon, likely organizing into a severe MCS across Iowa this
evening. Convective development is a bit uncertain north of the MCS
tonight. Consistency between CAM runs has been poor but the HRRR is
not handling the current convection well at all. There does seem to
be a trend toward a wetter solution along and west of the Mississippi
River overnight into Saturday, particularly with the global models.
A mid level trough will dig and become more negatively-tilted late
tonight across the Upper Midwest, with a deformation zone developing
north of the mid level low across central/southern MN. Pwats
remaining in the 1.5-1.75 inch range, along with some modest CAPE and
some low level forcing should allow additional convection to develop
overnight. The Iowa MCS will dive southeast into eastern MO quickly
later this evening and should leave little or no impact on subsequent
development here. PoPs have been increased to high chance/low likely
range west of the MS River. The showers and storms will be slow
moving and could result in locally heavy rainfall.
The upper low will continue to dig and eventually cut itself off
from the prevailing flow late Saturday. It will sag south slowly
through the day and take the deep moisture with it, resulting in
diminishing PoPs from north to south into Saturday evening.
.LONG TERM...(Sunday through Friday)
Issued at 323 PM CDT Fri Jul 9 2021
Mainly dry weather is expected for the latter half of the weekend
and into early next week, as any precipitation remains tied to the
cutoff low south of the area over the mid-Mississippi valley. Light
rain associated with the northern edge of the precipitation shield
could briefly reach into the I-90 corridor Sunday and portions of
west-central Minnesota Monday as the system begins to depart
eastwards, but dry weather is expected overall. Dry easterly flow to
the north of the surface low will keep temperatures seasonable and
dew points comfortable, with highs in the upper 70s to low 80s
generally expected.
Widespread precipitation chances return midweek, as most models
depict a shortwave tracking along the international border into the
region. While most guidance has a system midweek, there remains a
good deal of uncertainty remaining the timing and track of this
system, including whether precipitation is favored over northern or
southern portions of Minnesota and WI. Will stick with the general
20-30% PoPs from the NBM Tuesday through Thursday given the model
discrepancies, although much of that time frame will likely remain
dry. GEFS/EPS ensemble anomalies do not show much in the way of
precipitable water anomalies next week, so any precipitation we get
would likely be of the beneficial variety with widespread heavy rain
or flooding appearing unlikely. Temperatures and dew points will
increase midweek as low-level southerly flow develops, highs in the
mid to upper 80s and dew points approaching 70 look likely.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 655 PM CDT Fri Jul 9 2021
Main issue is the possibility of MVFR ceilings later tonight and
Saturday. East to southeast winds will prevail as a surface low in
Nebraska moves into Iowa Saturday morning. MVFR conditions now in
northwest Iowa will likely expand into southwest and south central
MN. Said ceilings may develop farther and north, but it is rather
uncertain whether MVFR will reach TAF sites from KAXN to KMSP and
KEAU. If it does, it would likely occur for only a few hours.
Otherwise, showers and storms in northeastern SD at this time may
reach southwest and south central MN late tonight.
KMSP...Kept a few hours of MVFR ceilings Saturday morning, currently
from 10Z-15Z. This is uncertain, but it would be the favorable time
for expansion of any MVFR from south central MN per short term models.
Otherwise, think showers Saturday morning will remain southwest of
KMSP, but this will need to be watched.
/OUTLOOK FOR KMSP/
Sun...VFR. Wind NE 5-10kts.
Mon...VFR. Slight chance MVFR/SHRA. Wind NE 5-10 kts.
Tue...VFR. Slight chance MVFR/SHRA. Wind SW 5-10 kts.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...None.
WI...None.
&&
$$
UPDATE...TDK
SHORT TERM...Borghoff
LONG TERM...ETA
AVIATION...TDK
Area Forecast Discussion
National Weather Service Spokane WA
348 PM PDT Fri Jul 9 2021
.SYNOPSIS...
The region will remain dry into next week with periods of breezy
winds at times. Temperatures will climb back into the upper 90s
and low 100s by Saturday, and remain above normal well into next
week.
&&
.DISCUSSION...
Tonight through Sunday night: The weather will be dominated by
hot, dry and occasionally breezy conditions. There will also be
some smoke mixed in, which could reduce visibility over some of
the eastern third of WA and the ID Panhandle. First high pressure
has been building in through today and it will be damped later
tonight into this weekend by a couple shortwave troughs moving in
from the Pacific. (The first is approaching the Vancouver
Island/northwest WA). Look for some afternoon cumulus around the
mountains, but little risk for precipitation. Milder air pumping
in ahead of these features will bring some hot weather, especially
Saturday. A heat advisory remains in place for Saturday for a
good portion of the CWA. It cools a little bit on Sunday, but not
by much.
Winds will be on the rise with these passing features as
well, largely for Saturday afternoon and evening and again Sunday
afternoon and evening. Gusts in the 15-30 mph range will be
possible. Combined with some low RH values this will lead to some
fire weather concerns near the Cascade gaps. (See the Fire
Weather section below for details on the Red Flag Warning.)
Before those winds pick up and as that first trough is
approaching, winds will turn more southeast to easterly tonight
into early Saturday. This is projected to draw smoke near the
Blue Mountain and Camas Prairie wildfires over more of our
region. HRRR and other model guidance is in decent agreement in
this evolution. However the bigger threat of reduced visibility
(less than 6 miles) will be closer to the wildfires: such as the
Blue Mountains, L-C Valley. Camas Prairie and into the Palouse.
But it is also expected to spread toward northeast WA and northern
Panhandle, though the first north you travel they less the
coverage is expected to be. The winds start to return to a more
westerly flow later Saturday into Saturday night. So for most of
the area, the smoke is not expected to be a long lasting thing.
The exception will be closer to the wildfires, i.e. near and east
of the Blue Mountains and lower ID Panhandle. /Cote`
Monday through Thursday: From a big picture standpoint, the
Northwest will be under primarily zonal flow aloft this week with
a few shallow shortwaves passing through. Monday afternoon and
evening may bring showers and thunderstorms to our northern zones
and especially the northern Cascades. Tuesday, Wednesday, and
potentially Thursday bring additional shower and thunderstorm
chances for much of the area with highest chances near the
mountains. A lot of our area probably won`t see a wetting rain
this week, but breezy winds are in store for Wednesday and
Thursday.
Otherwise, temperatures will generally reach into the 90s with
low 100s possible in the Moses Lake area and Okanogan and LC
Valleys. Thursday temperatures possibly cool to the upper 80s but
likely remain in the 90s for the warmer spots. Skies will be
mostly clear for the majority of the week except for areas
impacted by wildfire smoke.
Wednesday and Thursday are of concern for increased fire danger
due to breezy winds and fire starts from lightning. RC
&&
.AVIATION...
00Z TAFS: Mostly dry and VFR conditions with high pressure
building in. The main caveat will be wildfire smoke. Wildfires
near toward the lower ID Panhandle and Blue Mountains is expected
to expand later today into Saturday, potentially bringing MVFR
conditions near KLWS and KPUW. Closer to the fires themselves some
IFR vis are possible. Some is expected to push toward
KGEG/KSFF/KCOE toward Saturday morning, but the potential that it
will drop visibility to MVFR conditions is not certain. Winds
start to pick up Saturday afternoon. RC/Cote`
&&
.FIRE WEATHER...
Critical fire weather conditions from wind and low humidity are
expected in the lee of the Cascades late Saturday afternoon into
Saturday evening. Temperatures on Saturday will warm into the
upper 90s to lower 100s while humidity levels dip near 10 percent.
Northwest winds will increase in the afternoon and become strong
near or shortly after 5PM. The winds will be capable of rapidly
spreading any existing or new ignitions. Gusty winds will also
fan out on to the Waterville Plateau, Saddle Mountains, and into
the Moses Lake Area in the evening resulting in westerly wind
gusts up to 30 mph.
&&
.PRELIMINARY POINT TEMPS/POPS...
Spokane 60 97 60 95 61 96 / 0 0 0 0 0 0
Coeur d`Alene 57 96 59 93 59 95 / 0 0 0 0 0 0
Pullman 56 94 55 91 55 92 / 0 0 0 0 0 0
Lewiston 64 104 67 101 65 102 / 0 0 0 0 0 0
Colville 54 97 55 96 55 97 / 0 0 0 0 0 0
Sandpoint 52 93 53 92 54 92 / 0 0 0 0 0 0
Kellogg 63 93 64 90 63 92 / 0 0 0 0 0 0
Moses Lake 59 100 59 98 60 99 / 0 0 0 0 0 0
Wenatchee 68 98 64 96 65 98 / 0 0 0 0 0 0
Omak 63 101 63 99 65 101 / 0 0 0 0 0 0
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...Heat Advisory from 11 AM to 8 PM PDT Saturday for Lewis and
Southern Nez Perce Counties-Lewiston Area.
WA...Heat Advisory from 11 AM to 8 PM PDT Saturday for Lower Garfield
and Asotin Counties-Moses Lake Area-Northeast Blue
Mountains-Okanogan Valley-Spokane Area-Upper Columbia Basin-
Washington Palouse.
Red Flag Warning from 2 PM to 11 PM PDT Saturday for East
Washington Central Cascade Valleys (Zone 677)-East
Washington South Central Cascade Valleys (Zone 676).
&&
$$
Area Forecast Discussion
National Weather Service Norman OK
1053 PM CDT Fri Jul 9 2021
...New AVIATION...
.SHORT TERM...
(This evening through Saturday)
Issued at 328 PM CDT Fri Jul 9 2021
An isolated shower or two may affect SE portions of the fa this
afternoon but the current forecast remains dry (below 15% chance).
Models show showers and storms moving across portions of KS tonight.
Can not completely rule out some of this activity sneaking into
parts of far northern OK early Saturday, but will keep the forecast
dry for now. Breezy S to SW winds are expected again Saturday ahead
of a cold front.
A surface boundary is expected to start coming through northern
Oklahoma Saturday afternoon with a lagging upper level system during
the evening/overnight hours. Both ample moisture and instability
could potentially result in severe thunderstorms across much of our
area. Expecting the surface boundary trailing along an elongated
area of low surface pressure extending from eastern Kansas into
Iowa. All models begin pushing the boundary into northern Oklahoma
early Saturday afternoon. Ahead of this system under hot sunny
skies, diurnal heating along the surface boundary may erode the
inversion cap across northern Oklahoma as the afternoon progresses,
while so far the models maintain the cap across the rest of our
forecast area at least through Saturday afternoon. With surface
based CAPE values of 2000-3000 J/kg, moderate to strong instability
could result in severe convection developing toward late afternoon
across northern Oklahoma should the cap break, which would be likely
with the surface boundary coming through. DCAPE values would be
sufficient for damaging wind gusts along with large hail would be
the two severe hazards. The consensus from the latest CAMs run
starts breaking out convection toward late afternoon across northern
Oklahoma, with both the HRRR & NAM Nest members being the most
aggressive. As a result, will maintain POPs across northern
Oklahoma for Saturday afternoon. However, will need to monitor the
timing of the surface boundary into our north as well as the
afternoon cap strength across the rest of our area, especially
across central Oklahoma.
&&
.LONG TERM...
(Saturday night through next Thursday)
Issued at 328 PM CDT Fri Jul 9 2021
By Saturday evening, the upper low across the Central Plains/Midwest
will start digging a positively tilted trough into the Southern
Plain, as our northwest flow aloft will be increasing. Models start
to differ with the location of the surface boundary/front, with the
NAM & Canadian NH bringing it down into central Oklahoma along the
I-40 corridor, while the GFS & ECMWF keep it hung up and stretched
across northern Oklahoma. With the upper trough and surface
boundary in place, will expect to see convection become more
widespread through the evening hours. The severe risk will remain
even ahead of the front where moderate elevated instability from
steep mid-level lapse rates could result in strong to severe fast
moving high-based storms. However, expecting the severe risk to be
the highest near the surface front across central and northern
Oklahoma with the more slower moving cells. Large hail and severe
wind gusts will remain the primary hazards. However, with PW values
approaching 2-inches across northeastern Oklahoma, can`t rule out an
additional hazard of flash and river flooding from heavy rainfall
across eastcentral through southeast Oklahoma. After midnight into
the early morning hours of Sunday, expecting northern Oklahoma to be
dry with the storm POPs generally east and south of the I-44
corridor where the front should be.
With strong ridging persisting across the western U.S. and Eastern
Seaboard, long-range models block the upper low across the Midwest,
maintaining troughing across the central U.S. including the Southern
Plains into Monday. With the surface boundary lingering across our
south along with some mid-level vorticity disturbances rounding
through the trough, will restrict low POPs across southeast and far
southern Oklahoma and north Texas for Sunday, although not expecting
any of these storms to be severe. Although the surface boundary
should be washed out by Monday, additional mid-level disturbances
will keep low POPs across our far south for one more day. By
Tuesday, expecting the ridge across western Oklahoma to build
further east across our area maintaining dry conditions. However,
we`ll start seeing a strong return of south winds under the ridge
and start warming up more seasonably average into the lower to mid-
90s. By mid-week, the ridge starts breaking down with weak troughing
coming down from the north. As a result, could see storms return
across our north through the latter half of next week.
&&
.AVIATION...
(06Z TAFS)
Issued at 1051 PM CDT Fri Jul 9 2021
Still expect MVFR stratus late tonight thru Saturday morning for
most terminals. Wind speeds will remain around 10 to 15 kt from
the south overnight, and then shift slightly to the SSW and
eventually northwesterly behind a cold front Sat night.
Thunderstorms will accompany the front after 21Z through the
overnight Sat, especially across central and northern OK.
&&
.UPPER AIR...
Issued at 1207 PM CDT Fri Jul 9 2021
An Upper Air flight is currently planned for 12Z and 20Z Saturday
along with 0Z Sunday.
&&
.PRELIMINARY POINT TEMPS/POPS...
Oklahoma City OK 90 72 90 69 / 0 0 10 60
Hobart OK 93 72 94 69 / 0 0 10 40
Wichita Falls TX 92 73 95 72 / 10 0 0 50
Gage OK 96 73 93 66 / 0 0 20 10
Ponca City OK 93 73 89 66 / 10 10 60 40
Durant OK 90 74 91 74 / 10 0 10 70
&&
.OUN WATCHES/WARNINGS/ADVISORIES...
OK...None.
TX...None.
&&
$$
SHORT TERM...10
LONG TERM....68
AVIATION...03
Area Forecast Discussion...UPDATE
National Weather Service Portland OR
808 PM PDT Fri Jul 9 2021
Updated Aviation and Marine discussions
.SYNOPSIS...Persistent upper high pressure near the Four Corners area
will move slowly west through the weekend, while onshore flow at the
surface keeps the max temperatures moderated. Readings will continue
to be 5 to 10 degrees warmer than normal for mid-July, with dry
conditions expected for the next week. An upper low will begin to
slowly press down from the Gulf of Alaska to cool temperatures back
down towards normal for mid-week next week.
&&
.SHORT TERM...This evening through Monday...Many of the models are
in consensus that the shortwave ridge, which brought warmer-than-
average temperatures across most of the CWA today, will be
meandering east in advance of a weak impulse that is expected to
cross the region late this evening. While this area of 500mb
positive vorticity is not going to lead to CWA-wide precipitation,
it will promote an increased pressure gradient oriented to favor
onshore flow. This will form a decent flux of marine stratus both
along the coast and well into the Willamette Valley (through the
Gorge and Coast Range terrain gaps). In addition, the potential for
light drizzle along the coast is nonzero where the RAP and NAM are
actually depicting a small amount of QPF. At this time, elected to
leave the mention of drizzle out of the forecast as some forecast
soundings suggest the marine layer will be relatively shallow at
less than 2500 feet. This will be a point of consideration for
possible adjustments to the forecast in future shifts.
Tomorrow will be another warm day largely thanks to a slightly
weaker marine push overnight tonight compared with yesterday. High
temperatures will not be quite as warm as today with highs generally
2-5 degrees (F) cooler as the ridge`s axis will have shifted east of
our area. Westerly gusts to 25-30 mph are very possible along the
central Oregon coast, southern Willamette Valley downwind of Coast
Range gaps, and along the Columbia River Gorge (especially east of
Troutdale). Similar to Saturday, Sunday will feature morning stratus
and will be several degrees warmer than normal under weak
ridging/zonal upper-level flow. Will likely see afternoon breezy
winds.
-Bumgardner
.LONG TERM...Monday through Friday...The deterministic GFS and CMC
portray a kink in the predominantly zonal flow aloft rippling across
our area Monday, while the ECMWF has the feature further north.
Depending on the timing of the feature, this could favor an enhanced
marine push to yield more stratus and hence cooler high temperatures
Tuesday. There is also a chance for drizzle on Monday but decided to
leave out of the forecast at this time due to a lack of model
agreement in both the timing and strength of the feature.
By Tuesday models begin diverging significantly. The GFS shows a
shortwave ridge attempting to build between the exiting trough and
another incoming shortwave trough. The CMC has a similar shortwave
ridge amplifying just to our east in central and eastern
Oregon/Washington, and the second shortwave trough crossing our area
Tuesday afternoon. The ECMWF has our area in southwest flow with a
stronger, and a larger-scale upper level cutoff low spinning far to
our northwest in the eastern Gulf of Alaska. Thankfully, these
discrepancies are relatively minor, with most solutions from the
WPC`s cluster analysis suggesting a generally zonal synoptic-scale
weather pattern across the PacNW. While uncertainty is high at this
time for the end of the long-term period, the probability of
consequential precipitation appears low.
-Bumgardner
&&
.AVIATION...At 0300Z satellite imagery shows SKC conditions
across most of the forecast area while IFR marine stratus along
the coastline is beginning to push back onshore. Expect VFR
conditions to prevail for inland area through at least 08Z
Saturday. High resolution model low cloud guidance shows marine
stratus pushing up the Columbia River in Cowlitz County overnight
with about a 50 to 60 percent chance IFR to low-end MVFR cigs
develop in portions of the Willamette Valley between 12Z and 14Z,
primarily in the Portland metro area east of Interstate 5 and
also between KEUG and KS12.
IFR stratus will deepen at coastal areas this evening then
spread into the coastal valleys overnight. Areas from KONP to
K6S2 may remain IFR through 19Z Sat. Brief VFR conditions may be
possible along the coast by Sat afternoon but will likely be
mixed with low end MVFR stratus.
For detailed regional Pac NW aviation weather information, go
online to: https://weather.gov/zse
KPDX AND APPROACHES...VFR to prevail through at least 12Z Sat.
There is about a 50 percent chance low-end MVFR conditions
develop at the terminal and vicinity around 13Z Sat. VFR
conditions are expected again by 17Z Sat. /DDH
&&
.MARINE...The typical summer regime continues for the next several
days. Surface high pressure will remain anchored over the eastern
Pacific. A thermally-induced surface trough will reside along the
north California and south Oregon waters for the next several days.
This results in northerly wind over the coastal waters, strongest
during the afternoon and evening hours each day. The latest model
guidance suggests wind gusts to 25 kt over the central and
northern waters through late tonight. There looks to be a brief
break in small craft advisory level wind speeds Saturday morning.
The 12Z model guidance shows 25 kt gusts developing over PZZ255
and PZZ275 by early Sat afternoon and then spreading into the
south half of PZZ270 around mid-afternoon. Will issue a new round
of small craft advisories with this forecast.
The 12Z models suggest wind speeds ramp up a little more Sunday
afternoon, with small craft advisory conditions covering a larger
portion of PZZ270. Gusts 25-30 kt expected over a majority of the
waters Sun afternoon through early Mon. The strongest gusts will
be in PZZ255 and PZZ275. Wind speeds ease Tuesday night and
Wednesday as the pressure difference weakens and the marine layer
deepens.
Wave heights will remain below 10 feet for the next several
days. There will be a considerable wind wave or fresh swell
component, with a low-amplitude but long-period background
southwest swell. The fresh swell component builds into the 5 to 7
foot range around the middle of next week. Weishaar/DDH
&&
.PQR WATCHES/WARNINGS/ADVISORIES...
OR...None.
WA...None.
PZ...Small Craft Advisory until 11 PM PDT this evening for Coastal
waters from Cascade Head to Florence OR out 10 NM-Waters
from Cape Shoalwater WA to Cascade Head OR from 10 to 60
NM.
Small Craft Advisory from 2 PM Saturday to 2 AM PDT Sunday for
Coastal waters from Cascade Head to Florence OR out 10 NM-
Waters from Cape Shoalwater WA to Cascade Head OR from 10
to 60 NM.
Small Craft Advisory until 3 AM PDT Saturday for Waters from
Cascade Head to Florence OR from 10 to 60 NM.
Small Craft Advisory from noon Saturday to 5 AM PDT Sunday for
Waters from Cascade Head to Florence OR from 10 to 60 NM.
&&
$$
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AREA FORECAST DISCUSSION
National Weather Service Raleigh NC
945 PM EDT Fri Jul 9 2021
.SYNOPSIS...
A trough of low pressure will move offshore tonight. This
will be followed by drier weather overnight into Saturday. A more
typical summer-like pattern is expected from Sunday into next week
with near normal temperatures and chances of afternoon
thunderstorms.
&&
.NEAR TERM /THROUGH TONIGHT/...
As of 945 PM Friday...
The line of showers/storms was pushing offshore with plenty of high
and mid cloudiness left behind over central and western NC. THe
latest satellite data indicated the high clouds were thinning and
scattered from the west. Upstream, there continued to be partly
cloudy skies, thus our forecast will likely become partly cloudy in
all areas overnight. Probabilities of some ground fog are higher in
the central and east where the soils are wet. However, the scattered
clouds and slightly drier air in the lower and mid levels working in
from the west - northwest should keep the fog from being widespread.
Lows were dropped a bit in the NW given this information (with upper
60s there) ranging into the lower to mid 70s SE.
Previous update at issued 545 PM today...
We have had several Severe Thunderstorm Warnings this afternoon into
the early evening. These storms have been producing marginal severe
winds (highest reports in the 45 mph range). These winds combined
with the saturated ground have topped more trees than would normally
have fallen in a less saturated period. Most of the instability is
now along and south/east of the numerous outflow boundaries, mainly
along and ahead of the initial line of storms now extending from
Laurinburg to Fort Bragg to Smithfield and Wilson. The storms over
Raleigh are elevated and in the rain cooled air and producing heavy
rain and winds to 30 mph.
Another line along a wind shift boundary over the NW Foothills may
organized for a few hours as it moves into portions of the Triad.
These should remain below severe limits (gusts to 40-45) and in a
area that had less rain yesterday.
Previous discussion as of 208 PM Friday...
Early afternoon water vapor and vis satellite imagery reveal an
approaching longwave trough along the Appalachian Mtns, with a
developing cu field across the central Piedmont. Showers and
thunderstorms have re-developed within the lee trough across western
NC and VA, and have expanded in coverage as they`ve descended from
the higher terrain into an environment supportive of deep convection.
Latest SPC/RAP mesoanalysis suggests around 1500 J/KG of ML
instability across the region with upwards of 2000 J/KG across the
Sandhills. Surface dewpoints ahead of the approaching trough remain
in the mid 70s in the wake of TS Elsa and while PW`s are lower than
they were yesterday, they are still above normal for early July
around 1.7 inches.
Last few runs of the HRRR as well as the 12Z HREF have captured
current convective trends quite well, indicating a broken line of
convection moving through the area between now and 00-02Z with
intensification taking place as the storms move just east of the
Triad into the axis of peak instability. While the overall severe
threat is low (owed primarily to weak deep shear only around 15-
20kts), the strongest storms will be capable of gusty winds that
could approach severe limits. As the convection continues moving
east into the late afternoon, instability will eventually wane with
the loss of daytime heating and the line should begin dissipating as
it makes its way through the Coastal Plain. Brief periods of heavy
rain will also accompany the line but should not lead to significant
flooding issues.
Following the convective line, the longwave trough will drag a
boundary (or a very weak front, if you can even call it that)
through the area this evening. Some hi-res guidance is indicating
some secondary development along this boundary but the atmosphere
should be sufficiently overturned by that point to keep anything
from lasting too long. Thus I will keep the forecast dry this
evening. Temperatures and dewpoints tonight behind the boundary will
be very similar to what was seen this morning. Lows bottoming out in
the lower 70s with dewpoints thereabouts as well. Patchy fog is
possible tonight especially in locations that see rainfall this
afternoon but not an idealized setup for widespread dense fog.
&&
.SHORT TERM /SATURDAY THROUGH SATURDAY NIGHT/...
As of 100 PM Friday...
Saturday will start off dry with large scale subsidence across the
Piedmont. Meanwhile, an upper low will move from the upper Midwest
into IA/MO Saturday afternoon, pushing a weak boundary through
through the OH valley and into western VA/NC in the process.
Forecast profiles do not look overly supportive of precipitation
tomorrow given dry air and subsidence aloft but a few isolated
showers could develop east of the mountains within the lee trough
during the afternoon hours. Very low PoPs look more than sufficient
for tomorrow afternoon with dry weather forecast for the
evening/overnight hours.
Temps will be within a degree or two of normal with highs around 90,
lows in the lower 70s.
&&
.LONG TERM /SUNDAY THROUGH FRIDAY/...
As of 345 PM Friday...
The extended period will generally feature a typical summertime
pattern for central NC, with diurnal showers and storms each
afternoon and evening, quickly dissipating after sunset, and no real
frontal passages to speak of. The best chance of showers and storms
comes on Sunday, thanks to deep moist southerly return flow off the
Atlantic around both an upper low centered over IA/MO and a western
Atlantic ridge. The 12z GFS has precipitable water values near or in
excess of 2 inches over much of the area. Thus have chance POPs in
the east increasing to likely in the west where the best moisture
and instability will be. 0-6 km flow still looks too weak for any
organized severe storm threat.
As the center of the Bermuda high drifts farther west closer to our
region, subsidence and weaker moisture advection will then result in
decreasing shower and storm chances through midweek. Chance POPs on
Monday give way to the lowest POPs of the period on Tuesday and
Wednesday (slight to low chance), again highest in the western
Piedmont which will be farthest from the center of the ridge. The
GFS and its ensembles are farther west with the Atlantic ridge and
thus especially dry compared to the ECMWF. By Thursday and Friday,
as the next upper trough and associated cold front move through the
Upper Midwest, they will act to weaken the ridge and push it SE,
with a strengthening lee surface trough over the Piedmont. Thus
shower and storm chances should begin to increase again, but POPs
stay around 30-40% as there will continue to be a lack of any
forcing mechanisms.
High temperatures will be close to normal through the period (upper-
80s to lower-90s), with Tuesday and Wednesday likely being the
warmest days due to less clouds/precip. Enough clouds and moisture
will be around to keep lows near to slightly above normal, in the
upper-60s to lower-70s.
&&
.AVIATION /00Z SATURDAY THROUGH WEDNESDAY/...
As of 835 PM Friday...
A return to VFR conditions was spreading east across the region as
the thunderstorms have moved to our SE. There is a possibility of
some patchy MVFR fog (RDU,RWI,FAY) late tonight. Any fog that
develops will mix out quickly after sunrise.
Outlook: Looking ahead, Saturday will see a weak boundary lifting
north through the area but with large scale subsidence aloft, it
looks to be a mostly dry day at the TAF sites. Sunday onward will
see a typical summerlike pattern with VFR conditions and periods of
sub-VFR diurnally driven convection.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SYNOPSIS...Badgett/Leins
NEAR TERM...Kren/Badgett
SHORT TERM...Leins
LONG TERM...Danco
AVIATION...Badgett/Leins
Area Forecast Discussion
National Weather Service Reno NV
120 PM PDT Fri Jul 9 2021
.SYNOPSIS...
Dangerous levels of heat are forecast for this weekend into early
next week. Be sure to hydrate and limit outdoor activity during
the afternoon hours. A few afternoon and evening thunderstorms are
expected south of Highway 50 for the next few days. Smoke from
the Beckwourth Complex fire will affect portions of extreme eastern
California and western Nevada through at least the weekend.
&&
.DISCUSSION...
No appreciable changes to the forecast over the next week. The
long-advertised very hot temperatures are imminent (and already
started days ago out in Lovelock, Fallon, and Hawthorne) with today
starting the ramp up to the peak temperatures expected between
Saturday and Monday.
Heat
* High pressure peaking at 598-600 DM heights will build over
CA/NV this weekend. These heights correlate to impressive heat
for the region with 100 to 109 for lower valleys and upper 80s
to mid 90s for mountain communities expected. At this time,
reaching Reno`s all-time high of 108 only has about a 10-20%
chance of happening with 700 mb temperatures in models peaking
at near 19C (corresponds to 105-106). In any case, 105 versus
108 is unlikely to make much difference as it is still memorably
hot! Best advice is to limit outdoor activities, stay hydrated,
and check on those that are more susceptible to heat related
issues. Knowing the signs of heat illness could save a life.
Temperatures are expected to start easing down for the middle
to latter portion of next week (to within a few degrees of
average) as high pressure weakens with low pressure impinging
on the Pacific Northwest.
Thunderstorms
* Isolated coverage is expected for Mono, southern Lyon, and
Mineral counties each afternoon through at least Monday.
Saturday could have more expansive coverage as far north as I-80
between the Virginia Range and Highway 95/Fallon. Gusty outflows
40-50 mph and lightning will be primary threats from storms.
Storm chances may wane by Tuesday-Wednesday as stronger
westerly flow pushes convergence for storms away from western
NV and the eastern Sierra.
Air Quality
* Smoke associated with ongoing fires, like the Beckwourth Complex
and Tennant Fire, will continue to stream across the region.
Output from the HRRR smoke simulations still show increased
chances that smoke from the Beckwourth Complex will settle
farther southward than the last couple of days. This puts the
Reno Metro in the area for at least some haze over the next day
or so with some periodic degradation of air quality possible.
However, the worst conditions will be in proximity to the
Beckwourth Complex such as in Doyle and for areas east of there
out towards Lovelock and Fallon. Eastern Modoc County and the
Surprise Valley are likely see some decreases to air quality as
well from the Tennant Fire.
&&
.AVIATION...
Very hot temperatures continue this weekend and into next week with
density altitude concerns, particularly for smaller aircraft.
The Sugar Fire within the Beckwourth Complex in Plumas County
continues to burn actively with denser smoke expected in the morning
hours through the Doyle-Pyramid Lake areas becoming more diffuse
into Pershing and northern Churchill Counties. HRRR runs are even
indicating a period Saturday morning from approximately 12z-16z
where smoke may make it to around KRNO, but it doesn`t look overly
dense. Mixing during the daytime hours will bring improved visibility
outside of the areas immediately around the fire; however, slantwise
visibility may still be slightly restricted. General haze is possible
elsewhere due to other wildfires burning in the west.
Afternoon westerly winds today and Saturday will generally be lighter
than usual with peak afternoon gusts in the 15-20 kt range. We`ll see
winds return to "usual" levels Sunday with gusts to around 25 kts
and then there is potential for a slight uptick for the early part
of next week.
Isolated thunderstorms are possible this and Saturday afternoon/evening
(approx 20z-03z), primarily near and south of I-80. Storms initiating
in the Eastern Sierra may march north along the Pine Nut Range
before being shifted east as the afternoon westerly winds kick in.
Storms have the potential to bring localized heavier rain with
lowering CIGS/VIS and terrain obscuration. The greatest concern,
however, will be gusty and erratic outflow winds (40+ kts) from
any storms that do develop. Outflows may travel well away from the
parent thunderstorm and kick up dust across the west central Nevada
Basin and Range. -Dawn
&&
.FIRE WEATHER...
* Hot-unstable conditions favor plume dominated fires which may lead
to extreme fire behavior and rotating smoke columns for active
fires through Monday.
* Afternoon and evening thunderstorms possible today through Tuesday
for the Eastern Sierra and Sierra Front into central Nevada.
High pressure over the Desert Southwest and much of Nevada will lead
to an extended period of hot-dry-unstable conditions into early next
week. Minimum RH will remain in the single digits with poor recoveries
overnight. This requires a heightened fire weather awareness over the
next few days.
Winds...
Lighter than usual westerly afternoon winds are anticipated today
and Saturday with peak gusts mainly in the 15-25 mph range. We`ll
see more of a typical zephyr Sunday with speeds about 5-8 mph
stronger. Further uptick in wind speeds are looking probable the
early part of next week as the ridge diminishes a bit.
The one exception to the lighter winds today and Saturday will be
thunderstorm outflows. More details on that below.
Thunderstorms & Active Fire Instability...
A weak moisture push today and Saturday will lead to increasing
thunderstorm chances, but storm chances will also be somewhat
limited by the building ridge and subsidence aloft. Therefore,
coverage should remain rather isolated and storms may not grow
enough vertically to produce copious amounts of lightning with LALs
in the 2-3 range as a general rule.
Storms will be slow moving and with increased moisture could produce
decent rainfall under storm cores. Of course, there is still a risk
of a wet/dry hybrid situation with dry strikes igniting new fires.
These storms have the potential to produce strong outflow winds in
excess of 45 mph given the hot & dry surface conditions. Outflows
may travel a significant distance away from the parent storm, with a
5-10% chance of affecting the Beckwourth Complex this or Saturday
evening. Otherwise, activity looks to remain near and south of I-80,
initiating in the Eastern Sierra before marching north along the
Pine Nut Range. Storms will shift east after 4-5 pm as westerly
winds kick in.
The heat, instability, and some increase in mid-level moisture will
help promote pyrocumulus development over active fires; opening the
door for pyrocumulus column collapses. A few storms could linger into
the start of next week, but coverage does look to decrease.
-Dawn
&&
.REV Watches/Warnings/Advisories...
NV...Excessive Heat Warning until 9 PM PDT Monday NVZ001-004.
Excessive Heat Warning from noon Saturday to 9 PM PDT Monday
NVZ003-005.
CA...Excessive Heat Warning from noon Saturday to 9 PM PDT Monday
CAZ070-071.
&&
$$
For more information from the National Weather Service visit...
http://weather.gov/reno
Area Forecast Discussion
National Weather Service Blacksburg VA
959 PM EDT Fri Jul 9 2021
.SYNOPSIS...
Drier air will filter in tonight. The chance for showers and
thunderstorms return late tomorrow as a warm front arrives.
The daily precipitation chances continue, but will mainly
affect areas along and west of the Blue Ridge by Monday and
Tuesday. A western Atlantic ridge builds back into the southeast
by midweek.
&&
.NEAR TERM /THROUGH SATURDAY/...
As of 959 PM EDT Friday...
...Lowering humidity and clearing skies tonight with drier
conditions settling in Saturday...
Our weak frontal boundary from earlier this evening continues to
move off to our east across eastern Virginia and North Carolina.High
pressure over the Great Lakes region continues to slowly slide south
into the Ohio River Valley ushering in lowering humidity, clearing
skies, and calm winds overnight into the first half of Saturday. The
combination of clear skies, light winds, and low level moisture in
areas where showers may have passed through will lend it`s hand to a
few pockets of patchy valley fog heading into Saturday morning.
Highest confidence for fog looks to be across the Greenbrier Valley,
North Carolina Piedmont, and Virginia Southside per latest guidance
from both the HRRR and NAMnest.
As for temperatures, expect lows to drop into the upper 50s and low
60s west of the Blue Ridge with low to mid 60s out east. Humidity
will also drop off making for a relatively comfortable Saturday
morning whether your out for a jog or at the local farmers market.
Mostly sunny skies will be noted in most locations with cumulus
likely to build up with the peak heating of the day along and west
of the Blue Ridge. An isolated shower or storm can be expected in
these locations, but per current 18Z guidance from NAMnest, GFS, and
the latest NBM the bulk of any convective activity looks to remain
well to our west across western West Virginia and eastern Kentucky
where better forcing can be found along our next frontal boundary
lifting in. High temperatures Saturday afternoon will range from the
upper 70s in the mountains to lower 90s across the Piedmont.
By Saturday evening, our warm frontal boundary will start to lift in
as low pressure meanders over the central Plains region. Enough dry
air should remain in place from high pressure to the north to hold
any shower or storm activity west of the Blue Ridge. As a result, 30
percent PoPs will remain across our southern West Virginia counties
where the best bet for convective activity remains. Once again
coverage will be isolated to scattered at best. Storm coverage will
decrease with the loss of heating heading into the overnight hours.
Confidence remains high in the near term period on temperatures and
precipitation chances. Moderate confidence in regards to fog.
As of 730 PM EDT Friday...
The afternoon convection associated with the prefrontal trough
has pushed south and east of our area. This is supported by the
HRRR,HiResw-ARW and NAMnest. Skies will begin to clear tonight
as cumulus diminishes with the loss of solar heating. The
combination of light winds and low level moisture will result in
patchy fog overnight especially where it rained earlier and in
the river valleys. The Greenbrier valley has the best chance
for fog overnight. Adjusted temperatures utilizing the latest
surface obs, their trends and blended in the NBM for this
evening into tonight. Low temperatures overnight will be mild
with readings from the mid 50s in the mountains to mid 60s in
the piedmont.
Low pressure moving through the central Plains Saturday will
push will push a warm front north across our region. Scattered
showers and thunderstorms will develop during the afternoon
mainly in the west. High temperatures Saturday will range from
the upper 70s in the mountains to the lower 90s in the piedmont.
&&
.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY NIGHT/...
As of 1250 PM EDT Friday...
Daily chances of showers and storms with some strong storms
possible Sunday into Sunday night...
The forecast area Saturday night into Sunday night will be
positioned about half way between the center of an upper high
located off the coast of the Carolinas and a deepening upper low
that will settle over the mid-Mississippi Valley. The location of
these two features will help allow our region to experience increase
moisture flow off the Gulf of Mexico all the while good surface
heating takes place during the daylight hours. The Storm Prediction
Center`s Day 3 Convective Outlook places a Marginal Risk of severe
weather across mainly central and western parts of the region Sunday
into Sunday night in association with expected convection. The
heightened concern for severe weather potential coincides with a
shortwave trough rounding the base of the mid-Mississippi Valley and
heading northeast towards, or potentially across, parts of the
southern Appalachians.
Monday into Monday night, the relative positions of the upper low
and upper high stay about the same except for some retrograde of the
upper high towards the coast. Showers and storms will again be
possible during the afternoon and evening, but with perhaps a bit
less coverage as compared to Sunday. A slightly stronger cap aloft
with the closer proximity of the upper high is to blame.
Temperatures during this portion of the forecast are expected to be
near, or slightly above, normal for this time of year.
Confidence in the above weather scenario is moderate to high.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
As of 1210 PM EDT Friday...
Through the period at or above normal temps with daily chances of
afternoon/evening showers/storms mainly across the mountains...
During this portion of the forecast high pressure will remain
anchored off the coast of the Carolinas. This will help maintain a
southwest flow across the region, tapping the Gulf of Mexico. This
moisture will advect into the region. The degree to which there will
be an upper level trough across the Ohio Valley will vary, with
Tuesday, and then again on Friday, the time frame where the region
may have a bit more upper level dynamics involved for the
development of any showers and storms. Outside those two days,
diurnal and differential heating will be the primary feature to help
initiate convection, and the strength of the upper level high`s cap
across the area will limit coverage. The best coverage is expected
to be over the mountains, farther away from the center of the upper
high, and closer to any influence a central U.S. upper trough may
provide.
Temperatures through the period are expected to at or slightly above
normal.
Confidence in the above weather scenario is moderate to high.
&&
.AVIATION /02Z SATURDAY THROUGH WEDNESDAY/...
As of 821 PM EDT Friday...
The convection with the surface trough has pushed south and east
of our region this evening. As high pressure builds south from
the Great Lakes, drier air will filter in our region this
evening into tonight. Afternoon cumulus will dissipate with the
loss of solar heating this evening. This will allow skies to
clear tonight. With winds becoming light and variable tonight,
patchy fog will develop overnight. The taf sites with the best
chances for fog are KLWB, and perhaps KBCB which received rain
today. Sct to BKN VFR cumulus will develop Saturday afternoon
into Saturday evening. Isolated MVFR storms are possible in the
western mountains.
Average confidence for wind, ceilings and visibility.
Extended Aviation Discussion...
Moisture increases Saturday evening into Saturday night on back
side of surface ridge of high pressure and ahead of the next
slowly approaching frontal system.
Afternoon and evening MVFR shower and thunderstorm chances
increase each day from Sunday into Monday. Some of the storms on
Sunday in the mountains could be strong. For Tuesday and
Wednesday, thunderstorms will be more confined to the
mountains.The unsettled weather will continue for Thursday.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...None.
NC...None.
WV...None.
&&
$$
SYNOPSIS...ET/SH
NEAR TERM...ET/KK
SHORT TERM...DS
LONG TERM...DS
AVIATION...KK/SH