Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 07/20/21
Area Forecast Discussion...UPDATED
National Weather Service Albuquerque NM
603 PM MDT Mon Jul 19 2021
.AVIATION...
00Z TAF CYCLE
Upper level north to south ridge axis is over NM this evening. The
axis will remain over NM but will tilt to the northeast/southwest
during the next 24 hrs with drier air aloft continuing to spread
over ern NM. Isold showers and tstms will continue this evening with
brief MVFR cigs/vsbys in precipitation. Activity to slowly dissipate
through 06Z and mostly end after that. Similar convection scenario
Tuesday afternoon into the night.
&&
.PREV DISCUSSION...241 PM MDT Mon Jul 19 2021...
.SYNOPSIS...
A decrease in the coverage of showers and thunderstorms is expected
to continue through Tuesday before greater chances return to the
region beginning Wednesday. The focus for heavier rainfall will be
over northern, central, and western New Mexico Wednesday through
Sunday with localized flash flooding possible. Temperatures will
remain near to slightly below normal for mid July.
&&
.DISCUSSION...
SHORT TERM...(TONIGHT THROUGH TUESDAY NIGHT)...
Upper ridge axis stretched along the AZ/NM border and northward
today will slowly tilt in a clockwise direction during the next 24
to 36 hours. Some drier air at and above 500 mb has spread over
eastern NM and into portions of central NM as well with the main
moisture plume directed over AZ. The upper high circulation has
apparently spread some elevated smoke into the region, resulting in
hazy skies and which the HRRR indicates will persist in the short
term and possibly become a bit more concentrated. Otherwise,
southeast NM seems to be the focus area for storms this afternoon,
but LAPS is indicating the southwest portion of NM may become more
active later this afternoon or this evening, which the RAP13 and
NAM12 are hinting at as well. Isolated activity would persist over
southeast NM after midnight if the NAM12 is right. Northeast NM may
see an uptick in activity Tuesday as the ridge axis shifts. Not
confident the low clouds/fog observed this morning in far east
central NM or in the Moreno Valley will reappear tonight, so left it
out out the weather grids. Overnight lows will be a few degrees
warmer than normal, while highs on Tuesday will be near to below
average for mid July.
LONG TERM...(WEDNESDAY THROUGH SUNDAY)...
Wednesday will signal the beginning of a return to greater storm
coverage across the region thru the weekend. The wedge of mid and
upper level dry air sliding over the area Monday and Tuesday will be
shunted into southern NM and northern Chihuahua Wednesday. An axis
of 700-500mb layer deformation is expected to coincide w/ greater
moist instability over the northwestern half of our area Wednesday
and Thursday. This will increase the coverage of showers and storms
w/ heavy rainfall once again. An easterly wave approaching from TX
will increase subsidence over eastern NM where very little storm
coverage is expected both days.
Models continue to struggle w/ the progression of the easterly wave
Friday thru the weekend. There are big differences amongst models
with respect to the depth, location, and orientation of the wave
which will have impacts on the coverage and location of the heavier
rainfall across NM. At this time, a notable uptick in storm coverage
is expected over the western half of NM from Friday thru Sunday but
confidence remains very low east of the Cont Dvd. Either way, there
will still be abundant moist instability in place w/ slow storm
motion so locally heavy rainfall remains possible. Max temps will
also be near to slightly below normal for mid July areawide.
99/Guyer
&&
.FIRE WEATHER...
The upper ridge axis stretched along the AZ/NM border and northward
today will slowly tilt in a clockwise direction during the next 24
to 36 hours. Storm motion will generally be from northeast to
southwest through tonight, then may become more north to south over
eastern NM Tuesday while remaining northeast to southwest over
western NM. Cells may move more slowly and erratically Wednesday
with the upper high center becoming more elongated from west to
east. In any event, the focus for showers and storms will be
generally along and west of I-25 and along and north of I-40 through
much of this week. Highs will be near to below normal and overnight
lows will be a few degrees warmer than average. Winds will be light
outside of convective activity and areas of fair to poor ventilation
are forecast for portions of the north, west and central this week.
99
&&
.ABQ WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
Area Forecast Discussion
National Weather Service La Crosse WI
654 PM CDT Mon Jul 19 2021
.SHORT TERM...(This evening through Tuesday)
Issued at 240 PM CDT Mon Jul 19 2021
Surface high pressure was in control over the area with
thunderstorms continuing to roll southward out of northern MN.
Just west of the ridge is a CAPE pool that may allow a bit of
development westward toward/along the Red River. Current and
forecast instability shows a bit of instability into northwest WI,
but any forcing would have to be based on the system cold pool.
Expected impacts are high clouds at this time.
The MN thunderstorms initiated on an east-west cold frontal
boundary shifting south through southwest Ontario. This front will
travel south/west to about the Mississippi river by later Tuesday
and with ~2500 J/Kg of MLCAPE on the convergent boundary, some
storm chances exist. Wind shear does not look favorable for
organized storms, but a pulse strong to severe storm could occur.
With only shallow near-surface convergence the main forcing
mechanism, would expect isolated to scattered coverage of showers
or storms. Moisture will be pooling on the front which will
increase the mugginess in the area on and west of the front. Smoke
should increase Tuesday based on HRRR smoke guidance.
.LONG TERM...(Tuesday night through Monday)
Issued at 240 PM CDT Mon Jul 19 2021
A warm period with mid 80s to 90 expected depending on thickness
of smoke. On Wednesday and Thursday, there is good large scale
model consensus on more shortwave trough ripples in the northwest
flow. The shortwaves emanate out of the western U.S. monsoonal
airstream convection ongoing in NV/UT/ID. With the front in the
area and better low-level southwest flow, isentropic lift will be
increasing into the front. The NAM is most aggressive with the
low-level moisture transport but there seems to be forcing across
many models Thursday afternoon, especially in WI. With the front
evolving northeast slowly in warm advection, the placement is
still a question. If the front is still in the area, this again
provides more shower/storm chances, but not severe storms, and
mainly for WI.
Low-level warmth and warm advection continues into the late week
under the edge of the upper ridge and in northwest flow.
Temperatures may need to be raised late week. Good signals still
coming in about a Saturday convective complex mainly affecting WI
and probably elevated...but we will need to keep an eye on this
one.
&&
.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 650 PM CDT Mon Jul 19 2021
VFR conditions expected through the TAF period. Not anticipating
fog tonight at LSE given slightly stronger winds just above the
surface. Guidance does not suggest much potential for patches of
low stratus at LSE either; looking fairly dry near the surface
compared to previous nights. Have left low stratus out of the
TAFs for now but will monitor trends this evening.
A cold front will drop in from the northeast Tuesday afternoon.
Pretty low potential overall for showers and storms with this
front, but isolated convection is possible in the afternoon. Due
to low confidence/coverage, have left mention out of the TAFs for
now. Generally light winds under 10 knots through the period, out
of the west to southwest tonight, then shifting to the northwest
to north Tuesday afternoon.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...None.
IA...None.
&&
$$
SHORT TERM...Baumgardt
LONG TERM...Baumgardt
AVIATION...Kurz
Area Forecast Discussion
National Weather Service Bismarck ND
1001 PM CDT Mon Jul 19 2021
.UPDATE...
Issued at 957 PM CDT Mon Jul 19 2021
Thunderstorm activity has tamed down quite a bit, with only a few
little cells floating through eastern parts of our area. With that
said, will keep low chances in through the night as a variety of
weak disturbances moving through the ridge could cause a few
storms to develop. Have also spread areas of smoke through our
whole area as have noticed some lowered visibility reports
peppered through parts of western/central ND. In addition, models
are hinting at some fog possibly developing later over the
northern tier, where surface air is nearly saturated. So, have
spread the patchy fog across the far north.
UPDATE Issued at 708 PM CDT Mon Jul 19 2021
An area of thunderstorms, with one becoming significantly severe,
has developed over north central North Dakota where a plethora of
boundaries are noted. This is in an area of 40kt+ deep layer shear
and strong instability of around 2-3 KJ/Kg. The most significant
storm is now pushing south in southern McHenry County about to
slide into Sheridan and possibly far eastern McLean. This storm
has had a history of producing baseball hail and 70 mph wind
gusts. For the next few hours, expect the severe threat to
continue over north central North Dakota possibly nudging into the
northern James River Valley, with current development off to the
northeast of the significant storm. With that said, CIN expected
to quickly increase as we close into sunset, therefore expect the
severe threat to wane in a couple of hours.
&&
.SHORT TERM...(This evening through Tonight)
Issued at 229 PM CDT Mon Jul 19 2021
Fire weather, heat and thunderstorms (in no particular order) are
the main threats late this afternoon and tonight.
Fire Weather...We continue to hold in the near critical fire
weather conditions range, and unless we see winds really pick-up,
we`ll probably leave this as is. Current humidities are generally
around 15 percent in the far southwest, although did see Beach
drop down to 12 percent this hour. Other than the far southwest,
readings are generally 15 to 30 percent. Wind speeds are around 15
knots in the far southwest, but under 10 knots elsewhere. Given
the marginal area, and marginal thresholds will likely ride with
the near critical fire conditions.
Heat Advisory...The Heat Advisory continues through 9 PM CDT. So
far we`ve seen heat index values to around 103 at Bismarck, with
many stations in the 95 to 100 range as of 230 PM CDT. Maximum
heat indices look to peak around 4-5PM CDT and then drop off
thereafter.
Thunderstorms...A very unstable airmass remains over central into
eastern ND with MLCAPE values of 1500-3500 from north central into
east central ND with little CIN indicated from the EMC RAP on the
SPC mesoanalysis page. However shear remains weak. This would
favor possibly a marginally severe hail or wind event with an
updraft that can survive the cap. Recent convection that developed
near Jamestown was briefly able to sustain an updraft, but as of
300 PM the cell was dissipating. It`s possible we could see a few
more cells develop along the southward moving outflow boundary
this afternoon. Whether they can sustain themselves remains to be
seen. If so, a marginally severe wind or hail report can not be
ruled out base in the strong instability.
A baroclinic zone remains along the International Border and later
tonight it`s possible we could see a few storms along this
boundary and northward into Canada, but most will remain dry.
.LONG TERM...(Tuesday through Monday)
Issued at 229 PM CDT Mon Jul 19 2021
Hot and dry conditions continue through much of the work week.
A weak cold front moves through the forecast area in the Tue-Wed
timeframe with only slight chances for thunderstorms due to the
strong capping. Temperatures Tuesday through Friday remain in the
90 to 100 degree range across western and central ND, with the
warmest readings west and south central. Humidity values drop a
bit, but we could still be flirting with Heat Advisory criteria.
Most likely it will be a day to day call with marginal Heat
Advisory criteria possible each afternoon. There does look to be
an increase in surface based smoke tonight into Tuesday morning
north of the frontal boundary that`s been lingering along the
International Border. We kept a mention of smoke in the forecast
far north central late tonight into Tuesday morning, as well as
some patchy fog.
The best chance of thunderstorms in the next several days looks to
be on Friday as as stronger shortwave impulse tracks across
southern Canada and flattens our upper level ridge. This should
also cool us down a little through the upcoming weekend. At this
time it`s looking like mid 80s north to mid 90s south through the
weekend, so not a big drop in temperatures at all, but some
relief. After the chance of thunderstorms Friday, the rest of the
weekend looks mostly dry at this time, with indications of
possibly warming up again early next week.
&&
.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 708 PM CDT Mon Jul 19 2021
Ongoing strong/severe thunderstorms over north central North
Dakota will continue to settle southerly this evening, but at this
time do not expect them to hit any of the TAF sites. With that
said, additional development is possible, but will withhold from
mentioning in any TAFs as confidence is quite low whether they
would be affected. Otherwise, VFR conditions are expected.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...JJS
SHORT TERM...TWH
LONG TERM...TWH
AVIATION...JJS
Area Forecast Discussion...UPDATED
National Weather Service Brownsville TX
805 PM CDT Mon Jul 19 2021
.DISCUSSION...Updated for latest aviation discussion below.
&&
.AVIATION...Surface obs indicate that VFR conditions are
prevailing across the RGV this evening. The 00Z BRO sounding shows
a relatively dry atms over the region with a PWAT of 1.86 inches.
The latest HRRR guidance keeps the conv clear of the RGV
throughout the night with more conv firing off in central TX
closer to the cold front pushing into the region. The HRRR then
brings this conv north of a line from LRD-CRP by tomorrow morning.
This conv will likely take its time moving into the RGV due to the
slow movement of the cold front to our north. Guidance does
include a PROB30 group for the MFE are for tomorrow afternoon and
do not have much of an argument against this.
&&
.PREV DISCUSSION... /issued 259 PM CDT Mon Jul 19 2021/
SHORT TERM (Now through Tuesday Night): The mid level ridge will
remain over the Four Corners region through the short term, but
its affect on Deep South Texas will lessen as an elongated trough
over the Southeast CONUS extends across Texas. At the surface,
high pressure off the East Coast extending across the Gulf of
Mexico will allow light to moderate southeast winds to persist
through tomorrow morning. As the trough axis approaches Deep South
Texas tomorrow, rain chances will increase with the upper level
support, along with increased PWATs. WPC has included the northern
ranchlands and part of Zapata and Starr counties in a Marginal
Risk of Excessive Rainfall tomorrow through tomorrow night, so we
will watch for the potential for flash flooding in these areas.
Overall QPF amounts are expected to be in the 0.25 to 0.5 inch
range, but locally higher amounts will be possible. Winds will
decrease in response to an approaching cold front associated with
the trough and shift northerly or northeasterly during the day
tomorrow, but the south- southeasterly flow will return overnight
Tuesday night. The front will stall north of our area, so even
though there will be a weak wind shift, no CAA is expected.
Temperatures will be near climatological normal for overnight lows,
but will likely be a few degrees below normal for Tuesday`s high.
However, heat indices will top out in the 100 to 107 degree range
tomorrow afternoon, so it will still feel hot. Temperatures may not
quite reach this high if the cloud cover/convection is more
widespread, so this is a lower confidence forecast for tomorrow`s
temperatures.
LONG TERM (Wednesday through Monday): 500mb low/elongated trough
across east and south Texas Wednesday will continued to provide
unsettled weather across deep south Texas Wednesday into Thursday
as low to mid level moisture remains high across the area and both
the GFS and the ECMWF prog high rain chances Wednesday through
Thursday. WPC currently has the entire CWA in a marginal threat of
excessive rainfall for Wednesday. Will continue to mention showers
and thunderstorms across the Rio Grande Valley and northern
ranchlands Wednesday through Thursday before the 500mb
low/inverted trough across Texas Thursday begins to nudge
northwest as a 500mb subtropical ridge moves into the western Gulf
of Mexico Friday. This will provide drier air across deep south
Texas as well as an increase in subsidence across the lower Texas
coast. Rain chances will remain limited through the rest of the
week into the weekend as a result and temperatures in the
afternoon will return to near normal with the decrease in cloud
cover and rain chances through the rest of the forecast period.
MARINE (Now through Tuesday Night): Generally favorable marine
conditions are expected through mid week with wave heights in the
1 to 3 or 2 to 4 foot range and light to moderate winds expected.
However, isolated to scattered showers and thunderstorms will be
possible over the waters with heavy rain and occasional cloud to
water lightning tomorrow and tomorrow night.
Wednesday through Saturday...Light south to southwest winds will
prevail across the coastal waters Wednesday with a trough of low
pressure along the Texas coast. Winds will back to the south to
southeast Thursday with surface high pressure across the eastern
Gulf of Mexico. Light south to southeast winds will prevail
Thursday before increasing slightly on Friday as the pressure
gradient increases slightly across the western Gulf of Mexico.
Moderate south to southeast winds will prevail across the coastal
waters Friday with winds approaching SCEC conditions across the
offshore waters Fri night. The pressure gradient will remain
relatively strong across the western Gulf of Mexico Saturday with
SCEC conditions possible across the offshore waters.
&&
.PRELIMINARY POINT TEMPS/POPS...
BAYVIEW/PORT ISABEL 78 92 78 89 / 10 20 30 50
BROWNSVILLE 78 95 78 92 / 0 20 30 50
HARLINGEN 77 95 76 90 / 10 20 30 50
MCALLEN 77 95 77 91 / 0 30 40 50
RIO GRANDE CITY 77 98 76 94 / 10 30 40 60
SOUTH PADRE ISLAND 81 87 80 86 / 10 20 30 50
&&
.BRO WATCHES/WARNINGS/ADVISORIES...
TX...None.
GM...None.
&&
$$
This product is also available on the web at:
https://weather.gov/rgv
Short Term/Aviation...60-Speece
Long Term...55-Adams
Upper Air...65-Soria
Area Forecast Discussion
National Weather Service Burlington VT
1033 PM EDT Mon Jul 19 2021
.SYNOPSIS...
Hazy conditions will persist overnight and into tomorrow
morning due to smoke overhead from upstream fires. A cold front
will pass Tuesday afternoon, spawning showers and thunderstorms
during the afternoon and evening. A few of which may produce
gusty winds and locally heavy rain. Additional chances for
showers exists Wednesday through Friday and again on Sunday,
with generally cooler than normal weather persisting through the
period.
&&
.NEAR TERM /THROUGH TUESDAY NIGHT/...
As of 1033 PM EDT Monday...After flaring up quite nicely across
the Adirondacks, convection has begun to really diminish. Of
course, as I type this, new cell development has begun in
Franklin County, Vermont, but the trend should be weakening.
Raised PoPs over parts of Essex County, New York for a semi-
organized cluster of decaying thunderstorms. Fog can already
also be seen on nighttime microphysics satellite RGB, and the
haze will continue to persist overnight, and then worsen. Based
on conditions, expanded fog and also made note of reduced
visibilities from haze, as each new HRRR cycle continues to
paint a picture of a slight increase in smoke presence across
the lowest levels, which should be cleared as an oncoming front
pushes it south in the afternoon. The air will likely be
unhealthy for sensitive groups. The forecast is overall in great
shape. Previous Discussion below.
Overall, cloud cover should decrease overnight, though the
skies will remain hazy due to smoke from upstream forest fires.
In addition, patchy fog is likely to develop within favored
locations across the Adirondacks and eastern Vermont. Overnight
low temperatures will be in the low to mid 60s.
Tuesday will feature a passing cold front, with showers and
thunderstorms developing along and ahead of the front during the
afternoon and evening. Plenty of instability (>1000 J/kg of CAPE)
will be present ahead of the approaching front, owing to effective
daytime heating and dewpoints in the 60s. However, skies will again
look milky and hazy with smoke from upstream fires moving overhead.
Ultimately, this could limit the amount of heating and instability
available. On the other hand, synoptic lift will support the
development of thunderstorms with lowering heights as an upper level
trough approaches. Marginal wind shear and lapse rates will exist
across the North Country as well. This means that storms are likely
to develop along and ahead of the passing cold front, mainly between
noon and 8 PM, passing from north to south. Few of the storms have
the potential to become severe, producing strong, gusty winds. There
also exists the potential for localized heavy rain with PWATs of 1.3
to 1.5 inches. High temperatures on Tuesday will be in the upper 70s
to low 80s, with warmer temperatures to the south.
Thunder potential will decrease overnight Tuesday into Wednesday in
the wake of the cold front, though rain showers are likely to
continue as the upper trough continues to move overhead. Overnight
lows will be in the upper 50s to low 60s.
&&
.SHORT TERM /WEDNESDAY THROUGH WEDNESDAY NIGHT/...
As of 255 PM EDT Monday... Upper trough lags surface frontal
passage during Wednesday with continued cloudiness and a decent
chance of showers and perhaps a few storms, especially across
the eastern and southern portions of the forecast area. Shower
activity then ends by Wednesday evening as the trough pulls
east. Highs to remain seasonably mild in the 70s with overnight
lows mainly in the 50s. Patchy fog also a good bet Wednesday
night per low level moisture profiles.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
As of 255 PM EDT Monday...As discussed yesterday, the Northeast
remains in a northwesterly upper flow regime to the east of a
pronounced western US ridge through the Thursday through Monday
time frame. A weak feature embedded within this flow may spark a
few showers, mainly north and east on Friday. Otherwise dry
weather is expected through Saturday.
By next Sunday into Monday there is better consensus on a more
pronounced shortwave trough passage with a renewed threat for
showers and perhaps a few storms. Temperatures remain seasonably
mild through the entire period with daily highs in the 70s to
around 80, and overnight lows mainly in the 50s to lower 60s.
&&
.AVIATION /03Z TUESDAY THROUGH SATURDAY/...
Through 00Z Wednesday...Mainly VFR at this time with southwest
winds around 5 knots, except west at MSS. At MSS and SLK, haze
is being observed at 4 to 6 SM due to smoke from upwind
wildfires. This seems likely to continue overnight and reach PBG
shortly, but as winds become light and terrain driven past 03Z,
the progress of haze into Vermont will slow. Anticipate areas
of fog to develop at MSS, SLK, and MPV, generally at 1 to 4 SM,
and occasionally down to 1/4 SM visibility from roughly 06Z-12Z.
Around 12Z, anticipate a transition to west to northwest winds
around 5 knots, which will start to drive lower visibilities
from haze/smoke into Vermont, and have mentioned 4 to 6 SM
visibilities across the region as hourly smoke forecasts
indicate spreading and thickening over our region. Around 15Z,
scattered showers and isolated storms will begin to develop,
with a more concentrate area moving from northwest to southeast
beyond 18Z, which will also start to clear out remaining haze.
This activity will continue beyond 00Z Wednesday.
Outlook...
Tuesday Night: Mainly VFR, with local MVFR possible. Chance SHRA,
Slight chance TSRA.
Wednesday: Mainly VFR, with areas MVFR possible. Likely SHRA,
Slight chance TSRA.
Wednesday Night: VFR. Patchy BR.
Thursday: VFR. Patchy BR.
Thursday Night: VFR. Slight chance SHRA.
Friday: VFR. Chance SHRA.
Friday Night: VFR. NO SIG WX.
Saturday: VFR. NO SIG WX.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...None.
NY...None.
&&
$$
SYNOPSIS...Hammond
NEAR TERM...Hammond/Haynes
SHORT TERM...JMG
LONG TERM...JMG
AVIATION...Haynes
AREA FORECAST DISCUSSION
National Weather Service Sioux Falls SD
1050 PM CDT Mon Jul 19 2021
.SHORT TERM...(This Evening through Tuesday Night)
Issued at 248 PM CDT Mon Jul 19 2021
With weak flow aloft, afternoon satellite shows mostly clear skies
with surface observations climbing into the mid to upper 80s and
isolated 90s west of the James River. The weak flow aloft is
courtesy of a strong high pressure ridge which has set up across the
central Rockies and is looking to remain in place throughout the
work week. At the surface, a surface high pressure meanders a bit
around the central US, leaving the region predominantly under
southerly surface flow. For tonight, this will keep quiet weather
continuing, with possibly some patchy fog in low lying areas into
the early morning hours. One thing of note is the activity that is
currently ongoing in eastern ND and western MN, which has a
south/southeasterly trajectory. All the models point towards the
group of storms dying out as instability wanes this evening, but
it`s not out of the realm of possibility given the weak flow and
cold-pool driven convection.
On the backside of the ridge, the HRRR smoke trajectories indicate
the area will be socked in all day Tuesday with rather thick smoke
aloft. Good news is that the inversion above 800 mb should keep most
of the smoke from reaching the surface layer, which agrees with low
amounts of near-surface smoke that the HRRR is projecting.
Otherwise, expect mostly a repeat of Monday for Tuesday, with
slightly warmer temperatures as surface flow remains southerly, the
inversion aloft strengthens, and ample sunshine blankets the region.
Temperatures as a result will largely be in the upper 80s to lower
90s. Areas west of the James River will likely see winds pick up
a bit during the afternoon hours as a surface low pressure tries
to develop over WY, but gusts should remain under 20 mph.
.LONG TERM...(Wednesday through Monday)
Issued at 248 PM CDT Mon Jul 19 2021
As surface flow remains largely southerly thanks to that surface
high, expect temperatures to continue increasing throughout the
second half of the week. The aforementioned surface low continues to
try to develop as it slowly drifts eastwards, keeping the region in
an area of enhanced surface pressure gradient. With winds at the top
of the mixed layer in the 25-30 knot range, gusts of 25-30 mph
should be expected for areas along/west of I-29, with gusts in the
20-25 mph range elsewhere. With the stagnant pattern, temperatures
on Wednesday will be quite similar to those on Tuesday, again in the
upper 80s and lower 90s. RH`s look to remain above 30 percent, so
critical fire thresholds aren`t being met but certainly something
to keep in mind in case any burning is planned for Wednesday.
The previously shift mentioned a Wednesday night wave moving towards
the area, but the latest ensemble guidances (particularly the NBM
probabilities) have come in primarily dry. So, while a couple
deterministic models continue to hint at it being possible, have
left the populated guidance untouched thus a dry overnight period
into Thursday morning.
The forecast becomes a bit more uncertain for the rest of the
period, as the upper level heights remain fairly consistent and
eventually bringing the low pressure near/through the region. When
and how this occurs will certainly have effects on the temperature
and rain forecast, but for now have left the extended forecast
unchanged due to the uncertainty. This leaves temperatures to
continue climbing into Friday, with widespread temperatures in
the lower to upper 90s and heat indices approaching the triple
digit mark. A jet max looks to finally flatten the upper level
ridge a bit by the weekend, which should help get closer to more
seasonably normal temperatures.
&&
.AVIATION...(For the 06Z TAFS through 06Z Tuesday night)
Issued at 1050 PM CDT Mon Jul 19 2021
VFR conditions are forecast to prevail this TAF cycle. Much like the
past few days, look for wildfire smoke to linger overhead tonight
and tomorrow, with minimal impacts expected near the sfc. In
addition to this, could also see some diurnally driven cu develop
during the afternoon hours. Otherwise, expect light and variable
winds overnight to become south-southeasterly by tomorrow
afternoon.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
SHORT TERM...APT
LONG TERM...APT
AVIATION...SSC
Area Forecast Discussion
National Weather Service Glasgow MT
702 PM MDT Mon Jul 19 2021
.DISCUSSION...
EVENING UPDATE:
Minor changes were made to hourly Temp, RH, and Wind data sets to
keep up with observations through tonight. Currently a boundary
running from Opheim to just east of Saco to Winnett has sharpened
up heavier than the HRRR was predicting and has gained a slight
eastward component. It is unknown exactly where or if the boundary
will stall out, but areas just to the west and north of it are
experiencing a drop of 15 degrees compared to the southeast side.
GAH
AFTERNOON DISCUSSION:
The current heatwave is reaching its crescendo this afternoon,
with several records already falling as temps surge well above
triple digits. Some monsoonal is currently approaching northeast
Montana from the southwest, and could drive a few showers or
thunderstorms this evening and overnight tonight. Current suite of
hazard products including excessive heat warning and red flag
warning (through midnight) look on track.
Tuesday the thermal low will shift to the east, allowing for a bit
cooler temps across northeast montana, however the lower
yellowstone valley still looks to be near 100 degrees. Monsoonal
moisture will remain in the mix, keeping some mention of showers
and thunderstorms in the forecast.
Wednesday into Thursday The upper ridge will flatten out a bit as
an upper trough slides from British Columbia into Alberta,
allowing for continued chances for precip, and continued hot
temperatures.
Friday and beyond flattened ridging will keep above average temps
and dry conditions going for the foreseeable future.
Gilchrist
&&
.AVIATION...
LAST UPDATED: 0100Z
FLIGHT CAT: VFR.
SMOKE AND HAZE: Will continue to push through the area over the
next few days, lowering normal and slantwise visibility at times.
Currently MVFR visibility is not anticipated.
DENSITY ALTITUDE: With record highs across the area high density
altitude will take more power and runway distance to take off.
LLWS: Low level wind shear will be possible across the terminals
from about 04/06Z to 15Z.
WIND: Southeast at 10 to 20 kts this evening, reducing to 5 to
15 kts after midnight. Then increasing to 10 to 20 kts Tuesday
with varying direction wrapping around a low as it passes through.
DISCUSSION: Thanks to building monsoonal moisture thunderstorms
are possible tonight at KGGW though confidence is very low.
Isolated to scattered showers could expand to the other terminals
by late Tuesday morning.
/GAH
&&
.GLASGOW WATCHES/WARNINGS/ADVISORIES...
Excessive Heat Warning until 9 PM MDT Thursday for Central and
Southeast Phillips...Central and Southern Valley...Daniels...
Dawson...Eastern Roosevelt...Garfield...McCone...Northern
Phillips...Northern Valley...Petroleum...Prairie...Richland...
Sheridan...Southwest Phillips...Western Roosevelt...Wibaux.
Red Flag Warning until midnight MDT tonight for
MTZ120-122-134>137.
&&
$$
weather.gov/glasgow
Area Forecast Discussion
National Weather Service Grand Rapids MI
811 PM EDT Mon Jul 19 2021
LATEST UPDATE...
Update/Aviation
.SYNOPSIS...
Issued at 330 PM EDT Mon Jul 19 2021
- Very small chance for a shower over Central Lower this evening
- Better chances for showers/storms Tuesday afternoon/evening
- Thursday into Saturday precipitation chances
&&
.UPDATE...
Issued at 810 PM EDT Mon Jul 19 2021
Updated to add Ottawa, Allegan and Van Buren counties and adjacent
nearshore waters to the Beach Hazard Statement/Small Craft
Advisory, but with a later start/end time than the counties to
the north (issued earlier). The period of higher winds and waves
in this area is more for Tuesday evening whereas location to the
north will be seeing the increasing north flow and building waves
in the afternoon.
&&
.DISCUSSION...(This evening through next Monday)
Issued at 330 PM EDT Mon Jul 19 2021
- Very small chance for a shower over Central Lower this evening
Cannot rule out a small chance for a shower or a storm across
Central Lower Michigan this evening. MUCAPE values are on the
order of 1000-2000 j/kg across our eastern half of the forecast
area, essentially from U.S. Highway 131 to the east. There is some
convergence seen in the surface wind field across Central Lower
Michigan where a cumulus field has recently developed. The chances
are low 10-20 percent, so not zero this evening. Of the 5 models
in the SPC HREF only one from the 12z run is really showing any
precipitation. So, not out of the realm of possibilities, but the
threat is small.
- Better chances for showers/storms Tuesday afternoon/evening
Better chances exist for showers and storms tomorrow (Tuesday).
The chance of showers and storms will be forced by a cold front
dropping south through the Lower Peninsula. The issue though is
that the flow will be westerly ahead of the cold frontal passage
and that may advect in slightly more stable air off of Lake
Michigan. In looking at the SPC HREF there is definitely a better
chance of showers and storms to our west over Wisconsin and to our
east of Eastern Lower Michigan. Our chances for precipitation are
certainly not zero, but better chances exist to our west and east.
Right now we have a dry forecast towards Lake Michigan tomorrow
and 20-40 pct chance pops in the east. Based on the 12z SPC HREF
this looks good.
- Thursday into Saturday precipitation chances
Chances for showers and thunderstorms exist at times during the
period of Thursday through Saturday. A warm front will be situated
in the area during this time frame. Best chances will be when we
have some upper support that coincident with the surface front in
the area. That will be on Thursday and again Friday night into
Saturday.
The pattern will be dominated over the course of the next 7 days
with northwest upper flow (smoke will be likely aloft) and
occasional shortwaves rippling through the flow bringing us
chances for showers and storms.
&&
.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 810 PM EDT Mon Jul 19 2021
Smoke layer aloft is still present, likely located between 5K and
8K ft based on VAD wind profile and HRRR Smoke progs. 6 mile vsby
in haze at LAN indicates that some of the smoke has made it down
to the sfc. There`s also some high level cirrus cloud arriving
from the north tonight. Can`t rule out some patchy shallow ground
fog early Tuesday morning but was not confident enough to put in
any of the TAFs.
VFR continuing on Tuesday although winds increasing out of the
west to 10 to 20 kts in the afternoon, then shifting more
northerly later in the day with the passage of a cold front.
Can`t rule out a shower or even a tstm at LAN and JXN after 21Z
Tuesday, but best coverage expected to be farther east so have
not included that low threat in the TAFs.
&&
.MARINE...
Issued at 330 PM EDT Mon Jul 19 2021
We have gone ahead and issued both a Beach Hazards Statement and
Small Craft Advisory for Tuesday afternoon and Tuesday night from
Grand Haven off to the north. Winds increase behind a cold front
Tuesday afternoon with winds expected to reach 20+ knots at times.
This should be enough to push waves into the 3 to 5 foot range. We
feel these areas have the best chance at seeing larger waves.
There are indications that the waves may push into areas south of
Grand Haven as well Tuesday evening and Tuesday night, but at this
point we will wait on those areas for higher confidence.
High pressure builds in for Wednesday into Wednesday night with
quiet mid summer conditions expected during that time. The surface
pressure gradient is actually baggy into Thursday and Friday as
well, so little to no waves expected from Wednesday through
Friday.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...Beach Hazards Statement from Tuesday evening through Wednesday
morning for MIZ056-064-071.
Beach Hazards Statement from Tuesday afternoon through late
Tuesday night for MIZ037-043-050.
LM...Small Craft Advisory from noon Tuesday to 2 AM EDT Wednesday for
LMZ847>849.
Small Craft Advisory from 6 PM Tuesday to 8 AM EDT Wednesday for
LMZ844>846.
&&
$$
UPDATE...Meade
SYNOPSIS...Duke
DISCUSSION...Duke
AVIATION...Meade
MARINE...Duke
Area Forecast Discussion
National Weather Service Lincoln IL
931 PM CDT Mon Jul 19 2021
.SYNOPSIS...
Issued at 232 PM CDT Mon Jul 19 2021
Dry and seasonable weather is expected through much of this week.
Things turn hot and humid Friday into the weekend with heat indices
climbing into the upper 90s to 100. The next chance for
precipitation arrives for some later this week and for most this
weekend.
&&
.UPDATE...
Issued at 925 PM CDT Mon Jul 19 2021
Expansive high pressure at the surface from the Central Plains to
the central Great Lakes will keep our weather quiet tonight and
likely tomorrow as well. Light northeast winds and clear skies
will set the stage for light fog to develop late. The HRRR has
started indicating some patchy dense fog from BMI to CMI to
Taylorville. The GFS is broad brushing some light 4-5SM fog in a
large portion of our forecast area. Dewpoint depressions are still
on the high side for mid-evening, but ground fog will still be
possible in low lying areas and near waterways. Lows should
bottom out in the mid 60s, which is at or below the current
dewpoints. Will add some patchy fog for late tonight.
Otherwise, the forecast appears on track.
&&
.SHORT TERM...(This evening)
ISSUED AT 232 PM CDT Mon Jul 19 2021
Large-scale upper ridging remains in place over the western CONUS,
with northwest flow positioned over the Upper Midwest into the
eastern Great Lakes Region. At the surface high pressure is centered
over IA, with a stationary front stretched from the Mid-Atlantic
states to Texas slowly edging toward the Gulf as the surface high
builds southward. High pressure will keep the weather rather benign
here for the meantime with mostly dry and seasonable conditions
expected. Scattered diurnal cumulus blanket the area as of 2 PM,
with a hazy or milky look to the sky. This happens to be smoke from
western US and Canadian wildfires riding over the top of the ridge
and working it`s way into the Midwest states as it rounds the high.
This smoke will remain positioned aloft with little impact to air
quality. Instead, it will add an orange-pink hue to our sunsets over
the next few days. Light winds and clear skies overnight may allow
patchy fog to develop once again for some. Lows tonight will be
similar to last night, with values in the middle to upper 60s.
.LONG TERM...(Tuesday through Monday)
ISSUED AT 232 PM CDT Mon Jul 19 2021
Northwest flow remains positioned aloft through the long term
period. A few shortwave troughs look to ride the eastern edge of the
large-scale ridge this week, though most of these will impact the
Great Lakes Region through Thursday keeping any chances for
precipitation northeast of our area. The pattern looks to hold
steady until later this week as the ridge suppresses some and
migrates eastward as a trough moves onshore the Pacific NW. This
will act to move the surface high east of here, turning winds
southwesterly by Thursday. Temperatures and humidity will increase
going into the weekend with highs Friday into early next week
looking to peak in the low 90s with dewpoints in the low to middle
70s. This will lead to uncomfortable heat indices of 95 to 100+
during this time as well. The next chance for precipitation looks to
return across east-central IL Friday afternoon as a weak wave
ripples through the flow aloft. Better chances for showers and
storms for the entire area look possible later Saturday into Sunday
as a cold front sags southward from a wave topping the western CONUS
ridge.
&&
.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 652 PM CDT Mon Jul 19 2021
VFR conditions are expected to prevail through tomorrow afternoon.
Diurnal cumulus around 4k feet have nearly completely dissipated.
A layer of smoke aloft will keep a milky appearance to the skies
tonight, otherwise no clouds are expected overnight. Still seeing
indications of brief MVFR fog near PIA and BMI, but confidence is
low on that occurring.
Another day of patchy VFR CU are expected on Tuesday, but limited
BKN ceilings if any develop.
Winds will remain light overnight, mostly out of the northeast.
A wind shift to N-NW is forecast for Tuesday as the orientation of
the surface ridge alters slightly. Prevailing speeds should remain
less than 10kt.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...Shimon
SYNOPSIS...NMB
SHORT TERM...NMB
LONG TERM...NMB
AVIATION...Shimon
Area Forecast Discussion...Updated Aviation
National Weather Service Saint Louis MO
1040 PM CDT Mon Jul 19 2021
.SHORT TERM... (Through Late Tuesday Night)
Issued at 246 PM CDT Mon Jul 19 2021
Currently aloft, a broad trough is positioned over the eastern U.S.
with a series of shortwaves digging southward along its western
periphery across the Midwest and Plains. One of these shortwaves is
currently making its way out of the Middle Mississippi Valley and
providing weak lift across portions of central and southern
Missouri, where 2,500 J/kg of SBCAPE resides. This has allowed for
showers to recently blossom in these areas, and I expect the chance
for this isolated to scattered convection to continue in
southwestern portions of the CWA over the next several hours before
instability wanes and the shortwave continues southward. A mid-level
warm nose seen in model soundings is expected to keep convection as
mostly showers, but I can`t completely rule out a rumble of thunder.
Additionally, several recent HRRR runs have wanted to produce brief,
isolated showers in our Illinois counties this afternoon associated
with a weak shortwave in northern Illinois. However, the cumulus
through much of Illinois looks weak per visible satellite, and lapse
rates are very poor in this area, so I find this solution unlikely
at the moment.
Tomorrow, the lack of any apparent upper-level disturbances, poor
lapse rates, and capping are expected to keep the CWA rain-free. The
surface high that is currently in place over the Midwest will hold,
keeping temperatures similar to what they are today across the CWA.
Elmore
.LONG TERM... (Wednesday through Next Monday)
Issued at 246 PM CDT Mon Jul 19 2021
On Wednesday, the ridge over the western U.S. will build eastward
and broaden as the trough over the eastern portion of the country
slowly pushes off over the Atlantic Ocean. In response to this
upper- level pattern shift, the surface high responsible for our
weather early this week will shift eastward, placing the Middle
Mississippi Valley on its western periphery and returning
southerly flow to the CWA. This flow will help advect warmer air
and higher dew points into the region for the end of the week,
pushing temperatures to and then above normal for the weekend.
There are still subtle differences in the ridge`s eastward extent and
positioning this weekend and the phasing of an eastern upper-level
trough late weekend/early next week among ensemble guidance noted in
WPC ensemble cluster analysis. Even with these differences in ridge
placement, the recent run of the NAEFS and EPS have 850 mb
temperatures that line up with each other a little better than
previous runs for Friday and Saturday. Values at 850 mb are
currently forecast to be around 18-19 degrees C Friday, with
Saturday being the warmest at 20-21 degrees C. This correlates with
surface temperatures at or just above 90 for Friday and in the low
to mid 90s for Saturday. This aligns well with ensemble means during
this timeframe, which is representative of the current forecast. If
the ridge is able to shift a little further east, we could see
afternoon highs climbing a degree or two warmer that currently
forecast. With the return of the heat and humidity to the CWA, I
can`t rule out isolated to scattered diurnal convection during peak
heating in the extended period through Saturday over portions of
the CWA, but my confidence is greater in a dry forecast.
A leading shortwave ahead of an upper-level trough is forecast to
pass through the upper Midwest Saturday and Sunday, sending a cold
front through the Midwest late Saturday and Sunday. Understandably
at this lead time, there is much spread among guidance on the
placement and progression of the front, which decreases confidence
in temperatures and rain chances for Sunday and beyond.
Elmore
&&
.AVIATION... (For the 06z TAFs through 06z Tuesday Night)
Issued at 1039 PM CDT Mon Jul 19 2021
High pressure will continue to settle over the region, resulting
in tranquil conditions through the TAF period. The only potential
fly in the ointment is the potential for fog in the river vallies
in the early morning hours on Tuesday. Guidance still shows very
little in the way of fog development, but with dewpoint depressions
dropping to near or below 5 degrees and light winds, at least patchy
fog is possible. I`m not terribly confident that fog will develop,
so I`ve stuck with just 6SM BR at JEF, SUS, and CPS. That said,
if fog does indeed develop, I would not be surprised if visbys
drop below 6 miles at times.
BSH
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...None.
IL...None.
&&
$$
WFO LSX