Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 08/06/19
Area Forecast Discussion...UPDATED
National Weather Service Albuquerque NM
629 PM MDT Mon Aug 5 2019
.AVIATION...
00Z TAF CYCLE
Isolated convection will continue through the evening hours, mainly
along and east of the central mountain chain. High clouds will
increase from the south overnight as moisture surges up from Sonora.
An uptick in thunderstorm coverage is expected for all terminals
Tuesday afternoon and evening with the exception of KROW.
33
&&
.PREV DISCUSSION...452 PM MDT Mon Aug 5 2019...
.UPDATE...
Quick update to PoPs for this evening, dropping overall chances as
mid-level dry air wrapping into northwestern NM and subsidence
beneath the upper high has put a damper on storm development over
the northwestern high terrain. Also updated to take into account
lingering showers/storms along a bdry that has been picked up by the
RAP pushing into into east-central NM tonight.
24/RJH
&&
.PREV DISCUSSION...252 PM MDT Mon Aug 5 2019...
.SYNOPSIS...
An active week of afternoon thunderstorms will continue for western
and northern New Mexico after a relative down day today and this
evening. The best storm coverage for Tuesday will focus over/along
the western high terrain, shifting to the northern mountains
Wednesday. Some storms Wednesday over the northern mountains will
work their way into the northeastern plains by the evening. The upper
high jogs into Texas to end the week allowing for a better tap of
monsoon moisture into western and central New Mexico favoring more
afternoon storms for western, central, and northern New Mexico. The
southeastern plains will be relatively quiet in terms of storm
activity to end the week. Temperatures will remain near to above
normal through the forecast period with Tuesday and Wednesday likely
seeing a couple of 100s across the eastern plains.
&&
.DISCUSSION...
Tonight...Mid-level water vapor is showing some drier mid-level air
wrapping around the northwestern periphery of the high into
northwestern NM today, putting a damper on any thunderstorm
development there so far. Convection is developing over the
southwest mountains and central mountain chain with storm motions
generally toward the southeast/east. Lingering storms late into the
overnight period will favor south-central portions of the CWA.
Tuesday/Wednesday...Models continue to be in good agreement with
nudging the upper high center back over NM with a weak perturbation
along the western side of the high on Tue. This will help increase
storm coverage over the western high terrain and continental divide.
Storm coverage across the east will remain relatively low. Storm
motions, with little to no steering flow, will return to be slow and
erratic. Locally heavy rainfall and the threat for flash flooding
will return with any slow moving efficient rain producer across the
west Tuesday. The upper high center moves little Wednesday with the
aforementioned perturbation rotation around the high into the
northern mountains and into CO. Thus the highest coverage of storms
will shift to the northern mountains with storm motions increasing a
bit toward the east into northeastern NM Wednesday evening.
Late Week/Weekend...PWATs will remain 1-2 std deviations above
climatological normals ranging from 1.00"-1.20" at KABQ. Meanwhile,
both the GFS and ECMWF have continued to show an eastward progression
of the upper high into TX to end the week. This will allow a more
typical monsoon plume of moisture to advect northward into western
and central NM during this time keeping increased thunderstorm
activity going each day there. Storm motions also increase a bit from
S to N across the west, and more SW to NE or W to E over northern NM.
Daily trends will continue to favor the western and northern high
terrain for the first round of afternoon thunderstorms with lower
valley locations of western and central NM as well as the
northeastern plains likely receiving the second round late in the day
and evening. Unfortunately this pattern doesn`t favor robust
thunderstorm activity for southeastern portions of the state. Looking
even longer, the GFS is hinting at the upper high flattening and
more of a zonal flow pattern setting up over the northern CONUS with
drier air pushing into western NM for next week or mid-August.
24/RJH
&&
.FIRE WEATHER...
The high moisture content of the atmosphere remains intact as high
pressure aloft continues to orbit NM, yielding a typical monsoon
pattern for early August. This week, hot and seasonable temperatures
will be complemented by afternoon humidity typically falling to 25
to 45 percent, but good to excellent humidity recovery is expected
during the overnight periods. Otherwise the main fire weather
concerns will be dependent on scattered to numerous showers and
thunderstorms that will initiate over the southwestern to west
central and northern mountains of the state during the afternoons.
Storms will attempt to fill into adjacent lower elevations and
valleys each evening, but very low rain chances will persist for far
northwestern and far east central New Mexico. Storms will be slow-
moving and capable of producing heavy downpours with burn scar
flooding and gusty outflow winds threatening, as well as the
occasional new lightning ignition from strikes that occur away from
main precipitation cores.
52
&&
.ABQ WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
24
Area Forecast Discussion
National Weather Service Denver/Boulder CO
916 PM MDT Mon Aug 5 2019
.UPDATE...
Issued at 847 PM MDT Mon Aug 5 2019
A few showers and weak storms are ongoing over the northeastern
plains. These will continue through about midnight before
dissipating. In addition, a few showers are moving over southern
Park County this evening but will exit our CWA shortly. With
stable air elsewhere, POPs were lowered below 10 percent for the
rest of the night as dry conditions will prevail. Otherwise, the
forecast is on track for a quiet night.
&&
.SHORT TERM...(This evening through Tuesday)
Issued at 207 PM MDT Mon Aug 5 2019
Convection has fired across the foothills this afternoon and has
struggled to move off the higher terrain so far, because it is
encountering significantly drier air compared to yesterday.
Dewpoints have mixed out to 50 degrees south of the Cheyenne
Ridge. Dewpoints are still in the low 60s across northeast
Colorado, east of an Akron to Sterling line. Instability to the
west of the area of higher dewpoints is meager and should
support just widely scattered showers and thunderstorms into the
evening hours with gusty winds and not much rainfall. Convection
is a bit more robust across Larimer County and we still think
storms will expand in coverage across the Cheyenne Ridge and move
southeast across the northeast plains. PoPs are accordingly
highest there. The best chances this evening continue to be across
Larimer, Weld, Morgan, Logan and Logan Counties. Can`t rule out a
few storms across Park County and the Palmer Divide but recent
GOES-16 data suggest those areas are not as unstable as along the
Cheyenne Ridge. Impacts from storms this evening along the
Cheyenne Ridge would be gusty winds 40 mph or higher, brief heavy
rain, and some lightning. If any storms make it to the far
northeast corner there could be even stronger winds and marginally
severe hail.
With no significant forcing upstream, most areas will clear after
midnight and precipitation chances drop quickly, but latest runs
of the HRRR have an MCS moving southeast across Phillips/Sedgwick
Counties sometime between 3-6 AM. Instability and shear would
favor an MCS surviving the trek, so have introduced PoPs during
that time period. Strong winds, lightning, and brief heavy rain
would ensue if that occurs. Otherwise expect lows in the 60s
plains and 40s in the high country with mostly clear skies by
sunrise.
On Tuesday the persistent ridge remains over the Four Corners,
and the juicy monsoonal moisture is locked up to the south of
Colorado. Storm chances Tuesday afternoon should be isolated. PW
values remain on the low side as well, in the 0.5" range in the
mountains and 0.75-1.0" across the plains. Hard to pin down any
more favored locations for convection, but broad brush 15-30% for
northern quarter of our area plus the plains. Closer to the
moisture, have included a bit higher chance for Park County, the
I-70 corridor, and points south like the Palmer Divide. 700 mb
temps warm a few degC on Tuesday, to around +17 degC, and with
expected reduced cloud cover compared to previous days, low to mid
90s look attainable for the plains for highs, with 70s to low 80s
in the high country.
.LONG TERM...(Tuesday night through Monday)
Issued at 207 PM MDT Mon Aug 5 2019
For Tuesday night into Wednesday, isolated storms will propagate
across the eastern plains into the evening hours. With drying in the
lower levels storms will mainly produce gusty winds with some rain.
The high pressure ridge that has been dominating our weather pattern
over the last few weeks will move southeastward into New Mexico
during the day Wednesday and then into Texas by Thursday. This will
allow for embedded shortwaves to impact Colorado both days. For
Wednesday, the shortwave is currently projected to move into NE
Colorado by the afternoon helping to provide lift for storms that
afternoon. At the surface, a deepening lee side low will move
southeastward pulling winds from the northeast helping to increase
moisture along the foothills and adjacent plains. Scattered storms
will develop over the mountains and move onto the plains into the
evening hours. CAPE values will be decent with values upwards of
2000 j/kg east of a Sterling to Akron line with deep shear values
from 40 to 45 kts. This would support strong to a few isolated
severe storms across the NE plains with large hail and damaging
winds as the primary hazards. Wednesday will be the last above 90
day for the week with temperatures dropping into the 80s for the
remainder of the long term period.
On Thursday, surface high pressure will strengthen across the area
with continued easterly flow. This will help to maintain enhanced
upslope flow along the base of the foothills and moisture on the
plains. Model cross-sections show some cloud cover late Wednesday
into Thursday morning with the enhanced moisture along the foothills
and eastern plains. This cloud cover will hinder some solar
insolation and could delay mixing. Once the clouds are able to
dissipate, instability in the form of CAPE values from 1000 to 1500
j/kg and shear values from 30 to 35 knots will allow for isolated to
scattered storms Thursday late afternoon and into the evening hours.
Gusty winds and hail along with brief moderate to heavy rain will be
the main threats.
For Friday and into the weekend, another shortwave will move through
the region Friday afternoon. This will aid in the development of
storms for Friday afternoon. With precipitable water values well
over an inch across the eastern plains, the biggest threats from
these storms will be heavy rain, hail and gusty winds. For the
weekend, it appears the upper ridge will stay over the Texas region
keeping moisture levels on the moderate end over eastern Colorado
with some drying across the West.
&&
.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 847 PM MDT Mon Aug 5 2019
Two boundaries are colliding around DEN this evening with one
coming from the southwest and the other from the northeast. The
airmass behind each boundary is nearly similar so there is low
confidence on which one will win out. Winds may end up being
variable for a short time but south or southwest winds should
eventually prevail. Drainage flow will persist into the morning
hours before westerly winds increase shortly after sunrise.
Winds will be light throughout much of the afternoon tomorrow. A
stray shower or storm cannot be ruled out but coverage will be low
enough to not mention storms in the TAFs. The only affects on the
airports would be gusty outflow winds.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
UPDATE...Danielson
SHORT TERM...Schlatter
LONG TERM...Bowen
AVIATION...Danielson
Area Forecast Discussion
National Weather Service Columbia SC
1013 PM EDT Mon Aug 5 2019
.SYNOPSIS...
Scattered showers and thunderstorms are expected through
Wednesday as a surface and upper trough remain over the
forecast area. Typical summer weather is foreseen for the
remainder of the week with scattered diurnal showers and
thunderstorms.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
Water vapor imagery shows drier air aloft and a weak shortwave
pushing into the forecast area from the west. The few isolated
showers and thunderstorms will linger over the next few hours
supported by the shortwave and pockets of weak elevated
instability. We expect convective activity to diminish shortly
after midnight with the shortwave pushing to the east.
Light wind and clearing skies will lead to strong radiational
cooling and may allow patchy fog to develop around sunrise.
Lows overnight will mainly be in the lower 70s.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH THURSDAY NIGHT/...
The upper-level ridge will flatten and there could even be
some weak shortwave ridging building in on Tuesday. Meanwhile at
the surface, a weak/diffuse front will be stalled over the area
in the morning, but should shift toward the coast as the day
progresses. With the front shifting to the east and less upper
level support than the past few days, convection should be less
widespread. However, there will still be plenty of moisture
around with precipitable water values of 1.5 to 1.75 inches and
moderate instability in place, so will continue to show isolated
showers and thunderstorms in the afternoon and evening, with
scattered coverage across the eastern Midlands closer to the
front. Early morning areas of fog then stratus into midday
could keep temperatures down a bit, with highs around 90. Lows
Tuesday night should be in the lower 70s.
The upper trough should amplify a bit on Wednesday, with a
fairly moist southerly flow prevailing at the surface. No
significant forcing mechanisms will be present, but think the
pattern could support scattered showers and thunderstorms in the
evening. The trough axis and associated weak front at the
surface should pass through Wednesday night. Temperatures will
be on a warming trend, with highs in the lower to mid 90s and
nighttime lows in the lower to mid 70s.
The axis of the upper trough and associated surface front will
shift to the east on Thursday, resulting in a northwest flow.
Significantly drier air will advect into the region as a result,
with precipitable water values dropping to 1.25 inches or less.
Most areas will be rain-free, but the forecast does indicate the
potential for an isolated thunderstorm across the lower CSRA and
eastern Midlands in closer proximity to the front and greater
moisture near the coast. Highs will be in the mid 90s most
places with lows once again in the lower to mid 70s.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
The long wave trough will prevail over the western Atlantic
Friday through the weekend, maintaining a drier northwest flow
aloft across the region. While this drier airmass will
generally curtail shower and thunderstorm development, lower
confidence in the forecast as models show some disagreement on
timing/placement of shortwave disturbances moving through
within the northwest flow. For now will lean closer to
climatology with mainly diurnal isolated to scattered showers
and thunderstorms, with greater chances over the weekend than on
Friday.
Friday should be the warmest day of the week with highs in the
mid to upper 90s, with only slightly cooler temperatures
expected over the weekend.
&&
.AVIATION /02Z TUESDAY THROUGH SATURDAY/...
VFR conditions expected to start the forecast period but
restrictions in fog/stratus expected to develop during the
predawn hours.
Upper level trough axis continues to move through the area
overnight and still some lingering convection around the region.
Abundant low level moisture and some expecting drying in the mid
level overnight and not much of a low level jet should support
IFR fog/stratus later tonight. MOS guidance is indicating
visibilities and ceilings dropping around 09z or so and this is
supported by the latest runs of the HRRR so have made little
change to the previous forecast with restrictions beginning at
07z AGS/OGB and around 09z elsewhere. Winds will be light and
variable to calm overnight then pick up from the southwest to
south after 15z Tuesday with VFR conditions returning as cigs
lift into a cumulus field.
EXTENDED AVIATION OUTLOOK...Scattered mainly diurnal
thunderstorms as well as late night and early morning stratus
and fog will be possible, mainly through Wednesday. Drier
conditions then expected through late week.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
GA...None.
SC...None.
&&
$$
Area Forecast Discussion
National Weather Service Cheyenne WY
550 PM MDT Mon Aug 5 2019
.SHORT TERM...(This evening through Wednesday)
Issued at 210 PM MDT Mon Aug 5 2019
Forecast concerns in the short term deal with severe weather
chances.
Currently...Four Corners High still in place over said area this
afternoon. 12Z Grand Junction sounding showing PWATS slightly
dropping a bit this morning...but still right around an inch. At
the surface...cold front that was over northern Wyoming this
morning...is now being analyzed from just north of Alliance...to
south of Casper to near Cokeville in extreme western Wyoming.
Modest low level moisture increases observed behind the front with
dewpoints in the upper 50s. South of the front...dewpoints in the
mid 40s are common. Latest SPC Mesoanalysis showing surface based
CAPES in the mid 2000 J/KG across the Panhandle with 1000/1500
J?KG over southeast Wyoming. Radar starting to show initiating
across southern Albany County and extreme southern Laramie Range
at 144PM this afternoon. Storm motions have been to the southeast.
For this afternoon and tonight...Appears the HRRR simulated radar
is handling current storms the best and generally followed its
guidance through the period. Storms really begin developing after
22Z and take on a more easterly movement off the Laramie Range.
HRRR showing possibility of discrete supercells developing and has
one near Cheyenne...with another near Wheatland. NAM MU CAPEs near
2000 J/KG after 21Z on both the NAM and RAP. Better shear
today...on the order of 35-45kts should help in severe
thunderstorm development.
HRRR has been very consistent on developing a possible squall
line this evening up near Converse County with line bowing out
over Niobrara County and the northern Panhandle late this evening.
Would anticipate the evening shift issuing warning through late
evening and possibly beyond as the line shifts to the southeast
into the central and possibly the southern Panhandle after 08Z.
A slightly drier day with less convection expected Tuesday as
moisture shifts east into Nebraska. Still may see a couple severe
thunderstorms in the Panhandle Tuesday afternoon. SPC`s Marginal
Risk area looks good for the Panhandle.
.LONG TERM...(Wednesday night through Monday)
Issued at 210 PM MDT Mon Aug 5 2019
Thursday...Looks like a decent setup for scattered to numerous
showers and scattered thunderstorms in the afternoon and evening
with adequate low and mid level moisture, upslope low level
southeast winds and a shortwave trough aloft passing overhead
around peak heating. Temperatures will be cooler than Wednesday
with increased cloud cover and a greater coverage of showers and
thunderstorms.
Friday...With some decrease in low and mid level moisture, will see
a general decrease in shower and thunderstorm coverage.
Saturday...Ridging develops aloft, though with enough low and mid
level moisture, will again see isolated to scattered afternoon and
evening shower and thunderstorm coverage.
Sunday...Warmer temperatures aloft will help inhibit thunderstorm
development, thus the coverage of showers and thunderstorms will be
more isolated.
Monday...Somewhat drier air moves in at the low and mid levels,
making for a mostly dry day with perhaps an isolated thunderstorm or
two over and near the southern Laramie Range.
&&
.AVIATION...(For the 18Z TAFS through 18Z Tuesday afternoon)
Issued at 542 PM MDT Mon Aug 5 2019
Wyoming TAFS...Thunderstorms in the vicinity to occasional
thunderstorms at KCYS from 00Z to 03Z producing wind gusts to 25
knots and MVFR visibilities. KLAR and KRWL will see VFR conditions
this evening and overnight with wind gusts to 10 knots until 12Z.
Nebraska TAFS...Thunderstorms in the vicinity from 03Z to 05Z in
the Panhandle for airport sites. This trend will continue to quiet
down in the early night hours. KCDR and KAIA have the chance for
winds to die down and fog to develop between 07Z-09Z. Ceilings
will lower down accordingly. Expect skies to clear out by
daybreak.
&&
.FIRE WEATHER...
Issued at 210 PM MDT Mon Aug 5 2019
Minor fire weather concerns for Tuesday as monsoonal moisture
shifts east out of Carbon County. Could see afternoon humidity
falling to a little below 15 percent across Carbon County Tuesday.
Fortunately...winds are expected to be light...so fire weather
should be minimal Tuesday. Increasing moisture again Wednesday
into the end of the week as chances for wetting rains begin to
increase. Widespread showers and thunderstorms likely Thursday.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...None.
NE...None.
&&
$$
SHORT TERM...GCC
LONG TERM...RUBIN
AVIATION...BMW
FIRE WEATHER...GCC
Area Forecast Discussion
National Weather Service Des Moines IA
637 PM CDT Mon Aug 5 2019
.DISCUSSION.../Tonight through Monday/
Issued at 337 PM CDT Mon Aug 5 2019
Synoptic Overview:
Mid to upper-level flow over the upper Midwest will remain
northwesterly for much of this week, sandwiched between troughing
over the mid Atlantic and east coast with amplified ridging over
the western CONUS. A few short-wave troughs will slip through the
mid-level flow brining periodic rain shower and thunderstorm chances
this week. Temperatures to remain near seasonable in this large-
scale pattern.
Today and Tonight:
Severe weather potential will remain in place late this afternoon
through late this evening, especially across the north-central and
northeastern parts of the CWA where SPC SWODY1 enhanced risk is.
Slight Risk for severe weather extends to the southern and
southeastern portions of the CWA. Best moisture transport remains
across north-central and northeastern Iowa this afternoon ahead of
short-wave trough and associated cold front across the eastern
Dakota`s and Minnesota. GOES-16 visible imagery has been showing
decent clearing after this morning`s weak convection across northern
Iowa. CAMs continue to depict axis of greatest instability from EST
up through MSP, with SBCAPE in excess of 4000 J/kg. HREF mean SBCAPE
across the rest of the north and northeast CWA depicts SBCAPE
between 2500 and 3500 J/kg. In conjunction with thermodynamic
instability, HRRR and RAP soundings also depicting healthy low-level
lapse rates near 8.5 K/km and decent lapse rates through the mid-
levels. Thus anticipate healthy updrafts early on which may be
strong enough to present large hail threat. Effective bulk-shear 25-
30 knots should allow for decent organization of thunderstorms early
this evening, especially north of U.S. Hwy. 30. Low-level shear is
not overly impressive, a large factor into the limited tornado
threat with storms tonight. Dewpoint depressions values will be
quite high prior to the onset of convection. Combine this with
considerable low-level lapse rates, expect the potential for
damaging wind gusts with thunderstorms, with a few downbursts
favorable in this environment. There is still some discrepancy in
CAM runs this afternoon regarding the convective mode. ESRL HRRR and
NMM have attempted to develop bow-like features later this evening
into the overnight hours, which would align with the threat for
damaging wind gusts. Through the 16z runs, the HRRR was not nearly
as excited about bowing features along the cold front this evening.
However, CAMs are in decent agreement in highlighting areas north of
U.S. Highway 30 for active severe weather. The uncertainty with the
southward extent of severe weather this evening lies in how well any
cold-pool is maintained within the thunderstorm complex. If the
shear environment ahead of the boundary remains in place, there may
be enough balance to continue the severe weather threat as it
propagates southward. However, if this is not realized, it may just
lead to a widespread moderate rain showers south of U.S. Highway 30
to the Missouri state line. The only considerable change to the
forecast for thunderstorms tonight has been to delay the onset of
initiation a few hours. For Iowa, the bulk of the activity is not
expected until after 00 UTC. However a cumulus field is producing
precipitation as of 20z in northwestern Iowa. Given a favorable
environment, there is potential for this initial convection to reach
severe limits, thus have issued Severe Thunderstorm Watch 554 for
counties north of U.S. Highway 30 until 04 UTC tonight.
With respect to rainfall totals, thunderstorms will be rather
efficient this evening with PWATs around 1.75 inches. The flow
should be strong enough where the storms will progress at a decent
pace across the CWA. Looking at a widespread half to three-quarters
of an inch of rain, with up to 1.25 inches locally possible. With
rather dry antecedent conditions, not all too concerned with
flooding or flash flooding at this time. However, if the rainfall
begins to outperform the forecast, this may need to be adjusted. For
now, will hold off on any flooding headlines.
Extended Forecast:
Conditions dry out by Tuesday afternoon under northwesterly flow
with no short-wave perturbations in sight at this time as surface
high pressure slides in underneath. Next short-wave feature swings a
vort max through Iowa Wednesday morning brining rain showers
primarily to central and western Iowa during the morning and
afternoon hours. Mid to upper-level flow becomes relatively benign
toward the middle end of the work week through Sunday. Temperatures
in this pattern will remain seasonable in the mid to upper 80s for
the majority of this week. Substantial precipitation chances then
return to the forecast Sunday Night into Monday as another short-
wave trough works through the northwesterly flow over the upper-
&&
.AVIATION.../For the 00Z TAFS through 00Z Tuesday evening/
Issued at 637 PM CDT Mon Aug 5 2019
Surface front will slide through the state overnight with
scattered thunderstorms in vicinity of the boundary. Conditions
will be mostly VFR, but MVFR to IFR in and around thunderstorms.
Some areas of MVFR to IFR fog will also be possible around
daybreak with winds becoming light and variable along with
residual moisture from this evenings rainfall in surface layer.
Mainly VFR conditions on Tuesday with north to northwest winds.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
DISCUSSION...Krull
AVIATION...Cogil
Area Forecast Discussion
National Weather Service Indianapolis IN
1152 PM EDT Mon Aug 5 2019
.UPDATE...
The AVIATION Section has been updated below.
&&
.SYNOPSIS...
Issued at 238 PM EDT Mon Aug 5 2019
An isolated shower or storm will be possible this evening as high
pressure south of Central Indiana continues to drift southeast.
Most areas will remain just partly cloudy this evening.
Better chances for rain will arrive in the area on Tuesday as a
cold front arrives from the upper midwest. Showers and storms will
be possible on Tuesday as this front pushes across the state
through Tuesday.
More chances for showers and storms will persist on Wednesday
through Thursday night as a few weaker fronts push across Indiana.
Dry weather looks to return for the weekend as high pressure once
again builds across Indiana.
&&
.NEAR TERM /Tonight/...
Issued at 238 PM EDT Mon Aug 5 2019
Surface analysis early this afternoon shows high pressure in place
across SE Missouri...stretching northeast through the Ohio Valley.
Low pressure was found over Ontario...with a cold front stretching
southwest across Minnesota to the plains states. Dew points were a
bit higher today...in the middle 60s...as more of a westerly
surface flow has developed. GOES16 shows some diurnal cu building
across Central Indiana...and radar has hinted at a few isolated
showers trying to develop. Water Vapor imagery shows NW flow in
place across the region...flowing from a ridge axis across the
Rockies. A short wave was found from Minnesota to
Nebraska...pushing ESE. National Radar Mosaic shows a few showers
or storms entering the western Great Lakes.
HRRR shows a few scattered showers developing late this afternoon
across Central Indiana and given the latest radar and satellite
trends...this seems reasonable during our peak heating hours.
Forecast soundings and Time heights then dry out this evening as
heating and instability is lost...leading to another mainly clear
night. Thus will continue to keep some chances in late this
afternoon and evening.
The next short wave is expected to push into the area overnight
and forecast soundings hint at some high saturation arriving ahead
of this system. Thus will expect some increasing clouds late
overnight. Given the Warm air advection and cloud cover ahead of
the approaching system...will trend lows at or above the NBM.
&&
.SHORT TERM /Tuesday through Thursday/...
Issued at 238 PM EDT Mon Aug 5 2019
GFS and NAM both agree a short wave will push into Indiana on
Tuesday. NAM keeps the best forcing to the north while the GFS
bring significant forcing across the entire forecast area. Thus
Furthermore...both models bring the associated cold front across
Indiana during the afternoon...as best moisture should be ahead of
the lower level forcing. Thus overall feel best chances during the
day will be across the northern parts of the forecast
area...trending to lesser pops across the south. Given the
expected clouds and precip will trend high at or below the NBM.
NW flow continues to persist on Tuesday night through
Thursday...with a second...albeit weaker short wave passing
across the area on Wednesday. Lower level flow remains cyclonic on
Wednesday morning before a surface ridge finally builds in across
the area from the northwest on Wednesday afternoon. Little to no
upper support appears to arrive on Thursday. Thus will keep some
pops in place on Tuesday night and Wednesday morning as upper
support remains in play...but try to trend toward a dry forecast
by Wednesday night and Thursday as Ridging and NW flow resumes.
&&
.LONG TERM /Thursday night through Monday/...
Issued at 247 PM EDT Mon Aug 5 2019
The long term will start out with lingering chances for showers
and thunderstorms through Friday as a surface front slowly sinks
south of central Indiana with northwest flow aloft. High pressure
will build in from the northwest on Friday and by Friday night
should shove the front down to the south and allow dry conditions
to move into central Indiana. Temperatures will drop to near
normal early in the extended but then begin to climb as high
pressure builds over the area through the weekend and into next
week.
&&
.AVIATION /Discussion for the 06/06Z TAF Issuance/...
Issued at 1147 PM EDT Mon Aug 5 2019
A cold front will bring rain showers to central Indiana and are
progged to affect TAF sites by Tuesday afternoon. Conditions will
generally be at VFR levels for most of the TAF period outside of
any abrupt deterioration in visibilities during possible rain
showers. The only caveat will be when MVFR becomes prevailing at
KIND late in the TAF period. Meanwhile, winds will generally be
southwesterly at 5 to 10 kts.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...Puma
NEAR TERM...Puma
SHORT TERM...Puma
LONG TERM....CP
AVIATION...TDUD
Area Forecast Discussion
National Weather Service Pueblo CO
321 PM MDT Mon Aug 5 2019
.SHORT TERM...(This evening through Tuesday)
Issued at 321 PM MDT Mon Aug 5 2019
Drier air aloft has worked its way around the northwest side of the
upper ridge behind this mornings shortwave. Meanwhile, deeper
moisture continues to reside across the 4 corners region within
closer proximity to the monsoon moisture fetch around the upper high
centered over AZ. Still plenty of moisture over southern CO with
most areas in the 90-130% of normal range (highest values across the
east). Meanwhile weak surface front has pushed through southeast CO
with winds expected to gain a more northeasterly component into this
evening.
Thunderstorms have fired over the mountains and a few will drift off
into the adjacent plains late this afternoon through evening.
Satellite imagery also showing some convergence across Baca county
along stalled frontal boundary which may also help focus
thunderstorm development this evening as a few HRRR runs have
indicated. Models differ with how moist low levels will stay this
afternoon across the eastern plains with GFS and HRRR showing some
drying and limited CAPE...while NAM keeps dew points well into the
50s and CAPE values potentially up above 1500 J/kg across the far
eastern plains. Reality will probably end up somewhere in between
but have leaned towards the wetter solution based on latest dew
point trends. Main risks will be locally heavy rainfall, lightning
and gusty erratic winds. Small hail will also be possible with the
locally stronger storms, but with weak wind shear today, the threat
for severe thunderstorms looks low. Burn scars will need to be
monitored closely this evening for a flash flood risk given
relatively high precipitable waters and potential for heavy
rainfall. However, threat today looks pretty par for the course
during the monsoon season with nothing to sink our teeth into as to
which burn scars will be hit and which will not. Weak impulse energy
may help maintain thunderstorms across the southeast mountains
through the evening hours and will maintain some isolated pops past
midnight.
Low level flow swings around from the southeast across the plains
maintaining 50 dew points across the lower elevations on Tuesday.
Meanwhile, moisture plume aloft will start to spread back northward
into more of the western mountains. Really not a lot of change to
the forecast for Tuesday with another round of scattered
thunderstorms expected in the afternoon across the mountains,
spreading eastward during the late afternoon and evening along
surface trof axis. With weak shear, and high precipitable waters,
heavy rainfall carrying a localized flash flood threat will be the
primary concern. -KT
.LONG TERM...(Tuesday night through Monday)
Issued at 321 PM MDT Mon Aug 5 2019
Tuesday night-Wednesday night...Modest northwest flow aloft across
the region on Tuesday becomes more westerly through the day on
Wednesday, as upper high pressure across the Desert Southwest is
slowly shunted south and east by a broad upper trough translating
across the Northern Tier. This will allow for atmospheric moisture
to increase across the region, especially along and west of the
ContDvd on Wednesday. This, along with a weak front expected to back
into eastern Colorado through the afternoon, will allow for
increased coverage of afternoon showers and storms across the area
on Wednesday, especially over the higher terrain. Increased low
level moisture behind the weak front, with a slight increase in
shear, could produce a few stronger storms across the far eastern
Plains late Wednesday afternoon and evening. Temperatures on
Wednesday look to be around to slightly above seasonal levels,
warmest across the eastern Plains.
Thursday-Friday...Models in decent agreement of the "monsoonal
moisture" tap moving across the region within weak southwest flow
aloft, as upper level high pressure continues to be positioned
south and east of the Rockies. This, combined strong solar heating
and moist low level upslope across the Plains, will bring better
coverage of afternoon and evening storms across all of south
Central and southeast Colorado, with the best coverage over and
near the higher terrain through the afternoon, with storms moving
east across the Plains through the late afternoon and evening.
Weak westerly steering flow aloft will allow for locally heavy
rainfall and the potential for flash flooding, especially for the
newer burn areas of the Spring, Junkins and Hayden Pass scars.
With the better chances and coverage of storms, highs through this
period look to be at to slightly below seasonal levels.
Saturday-Monday...Upper level high pressure is progged to slowly
retrograde west through the weekend, with drier air within the more
westerly flow aloft expected to slowly decrease the coverage of
afternoon and evening storms by early next week. Best storm coverage
over the weekend will be over and near the higher terrain, with the
continued weak steering flow leading to locally heavy rainfall and
the potential for flash flooding through the weekend. Temperatures
look to be around seasonal levels through the period.
&&
.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 321 PM MDT Mon Aug 5 2019
VFR conditions expected at the terminals with erratic gusty outflow
winds up to 40 kts possible near VCTS. All three terminals will
carry some risk for -TSRA through the evening, though primary impact
will be shifting winds from thunderstorm outflows. VCTS will
persist the longest for KPUB and KALS but all three terminals should
see diminishing probabilities after 06z with VFR conditions expected
overnight. Northerly winds today behind the cold front will
transition back to south to southeasterly for Tuesday with
thunderstorms expected to develop over the mountains again during
the afternoon. -KT
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...KT
LONG TERM...MW
AVIATION...KT
Area Forecast Discussion
National Weather Service San Diego CA
153 PM PDT Mon Aug 5 2019
.SYNOPSIS...
Moisture aloft will move into Southern California overnight
through Tuesday around the western periphery of an upper level
ridge over Arizona. This could result in a few lightning flashes
and strikes over San Diego and portions of Riverside County
overnight through Tuesday morning. Then, a few thunderstorms could
develop over the mountains on Tuesday afternoon. A weak trough of
low pressure off the coast will spread cooling inland through
midweek. Some slight additional cooling is possible for Friday
and Saturday as a low pressure system moves inland into the
Pacific Northwest. Warming will resume around Sunday as a trough
of low pressure near the West Coast weakens. Night and morning
coastal slow clouds will extend into portions of the western
valleys at times.
&&
.DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE...
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...
.Highlights...
* Slight chance of dry lighting San Diego and southern Riverside
Counties after midnight tonight-Tuesday morning
* Thunderstorms possible over the mountains Tuesday afternoon
Some changes to the forecast this afternoon. A complex of
thunderstorms over the northern Gulf of California will continue
to spread west-northwest while dissipating. However, moisture
from this complex will spread north of the international border
tonight, especially after midnight. The moisture will be confined
above 12,000 feet with very dry air remaining below. HRRR and WRF
do show some elevated CAPE spreading in from the south after
midnight. This leads to concern for dry lightning potential
overnight-Tuesday morning. For this reason, added in a slight
chance of dry lightning for San Diego County into southern
portions of Riverside County after midnight tonight through
Tuesday morning. Low confidence, but enough concern to mention the
potential.
The peak of the moisture, PW near 1.40 inches, will occur Tuesday
afternoon and this could lead to a few thunderstorms developing
over the mountains Tuesday afternoon. The big limiting factor for
tstorm development Tuesday will be a mid/high level cloud shield,
but hi-res models do show the possibility of some rainfall
occurring over the mountains, albeit light.
The heat is really on this afternoon over the lower deserts. It`s
looking like temps could reach 120 at a few locales. The forecast
was updated earlier to reflect this higher trend. The good news is
cloudiness spreading in from the south tonight-Tuesday will lead
to a reduction in temps tomorrow and for the middle to latter part
of the week, an upper level trough digging in from the northwest
will lead to lowering heights/thermal fields, keeping excessive
heat at bay, so today is the last day of the brutal heat there.
Heat headlines will expire at 8 PM this evening.
&&
.LONG TERM Thursday through Sunday (From previous discussion)...
Minor changes are expected for Thursday. Friday and Saturday may
cool slightly as a low pressure system moves inland into the
Pacific Northwest. Warming will resume on Sunday as a trough of
low pressure near the West Coast weakens. Night and morning
coastal low clouds will extend inland into portions of the western
valleys at times.
&&
.FIRE WEATHER...
* Slight chance of dry lightning after midnight tonight-Tuesday
morning
Moisture aloft will be spreading in from the south tonight with
the potential of a few lightning flashes and strikes after
midnight over San Diego and southern Riverside Counties. Low
confidence on this, but the potential is there. This would not be
a widespread lightning event with only a few strikes to occur, if
at all.
There is a better chance of lightning over the mountains on
Tuesday afternoon, although still low probabilities and we expect
those to be associated with some light rainfall as further
moistening occurs.
&&
.AVIATION...
051940Z...Coast...VFR conditions prevailing through 02Z, with OVC006-
010 tops 015 redeveloping after, spreading 10 mi inland affecting
KSNA/KSAN/KCRQ. Areas VIS 3-5 SM 06/10-16Z, mainly affecting coastal
mesas and higher coastal terrain. Slight chance of lightning after
midnight. Low confidence.
Valleys/Mountains/Deserts...FEW-SCT high clouds AOA 20,000 ft MSL
and unrestricted VIS through Tuesday PM. Slight chance of
lightning after midnight SD and southern Riverside Counties, then
over the mountains Tuesday afternoon. Low confidence.
&&
.MARINE...
NW gusting to around 20 kt winds will occur near San Clemente Island
each evening through Wednesday. Otherwise, no hazardous marine
weather is expected through Friday. Slight chance of lightning near
San Diego County coast tonight into Tuesday, but confidence is low.
&&
.BEACHES...
Slight chance of lightning tonight into Tuesday. Low confidence.
&&
.SKYWARN...
Skywarn activation is not requested. However weather spotters are
encouraged to report significant weather conditions.
&&
.SGX WATCHES/WARNINGS/ADVISORIES...
CA...Heat Advisory until 8 PM PDT this evening for San Bernardino and
Riverside County Valleys-The Inland Empire.
Excessive Heat Warning until 8 PM PDT this evening for Apple and
Lucerne Valleys-Coachella Valley-San Diego County Deserts-
San Gorgonio Pass Near Banning.
PZ...NONE.
&&
$$
PUBLIC...Gregoria
AVIATION/MARINE...Rodriguez