Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 07/25/19

Area Forecast Discussion

National Weather Service Detroit/Pontiac MI

 1146 PM EDT Wed Jul 24 2019


.AVIATION...

Aside from a few mid/high level clouds, ample low level dry air
associated with high pressure over the srn Gr Lks/nrn Oh Valley will
sustain clear skies below 8k ft through Thurs morning. This high
will also support light winds through the TAF period.

.DTW THRESHOLD PROBABILITIES...

* None.

&&

.PREV DISCUSSION...
Issued at 349 PM EDT Wed Jul 24 2019

DISCUSSION...

Broad anticyclonic flow will build northeastward today as a low to
mid-level ridge axis pushes east. Given the synoptic setup with
broad subsidence in place and an expansive area of positive omega, a
dry forecast will be maintained. Midday obs have confirmed mostly
sunny skies with a patchy cu field noted in satellite imagery over
the Metro area and toward the MI/OH border. Any additional cu that
develops later today should stay elevated with mixing depths around
6 kft. One small point of concern is related to the progression of a
line of showers working SE from northern Lower Michigan along a H7
shortwave. Given drier flow, higher stability, and isentropic
downglide, the expectation is that any remaining showers will
entrain out and dissipate before crossing into the CWA.
Thermodynamically, the diurnal heating rate was a bit accelerated
earlier, prompting a late morning temperature update. With 12Z 850
mb temps in the 12-14 C range, expect daytime highs to top out
shortly in the upper 70s to low 80s. Surface winds will generally be
light from the NNW providing no meaningful change in the low-level
moisture profile, keeping dewpoints at bay /in the 50s/ and slightly
cooler than climatological norms.

Nocturnal inversion sets up tonight helping maintain calm to weak
winds within a highly stable BL. Radiational cooling will not be
maximized overnight due to mid-level cloud deck keeping overnight
lows in the upper 50s to low 60s. Still, 2-4 degree dewpoint
depressions should be large enough to avoid fog development. Looking
ahead to Thursday, the CMC and GFS are outliers as they try and
advertise QPF in the Thumb region from H5 shortwave ripples along
the apex of the ridge. Even if there was some induced lift, any
precip would be high based and likely evaporate before reaching the
surface based on saturation levels from RAP soundings. Flow becomes
more zonal at the surface while veering with height before becoming
SW on Friday. Daily increases in H5 heights suggests a gradual
warming trend into the the weekend with dry conditions.

Ridge of high pressure will continue to hold in place across the
Great Lakes down into the Ohio Valley and east over the Continental
northeast on Saturday. This sprawling high pressure system will
result in dry weather and extended period of sunshine, pending some
diurnal cumulus. Return flow from the departing high pressure system
and strengthening low-level jet will act to increase temperatures to
above-normal values, marked by h850 temperatures increasing slightly
from an average of 14C (18Z Fri) to 16C (18Z Sat), which will
translate to an increase in daytime high temperatures into the mid
to upper-80s starting Saturday. It is possible portions of Metro
Detroit could approach or touch 90 over the urban heat island.
Influx of warmer temperatures will also bring little relief
overnight as lows hold in the upper-60s to lower-70s Saturday into
Sunday and Sunday into Monday. Lack of significant forcing will keep
rain and thunderstorm chances low over the weekend as a series of
weak shortwaves travels over the area. Better chances for and
thunderstorms to enter early next week, tied to an approaching cold
front, which will also act to return temperatures to near or
slightly below normal highs (low to mid-80s) by Tuesday.

MARINE...

Outside of widely scattered showers across northern Lake Huron the
remainder of today, dry weather will prevail through the day Friday
as high pressure expands eastward across the region. The high
pressure will allow for light southwest to southerly winds across
the local waters through Thursday. Southwest winds will then become
moderate at times with gusts 15-20 knots, especially across Saginaw
Bay and into the central Lake Huron basin, Friday and heading into
the weekend as the area of high pressure slides eastward and the
pressure gradient tightens slightly ahead of an approaching cold
front from the northern Great Lakes. This cold front will bring
increasing chances for showers and a few thunderstorms Friday night
and into the weekend, especially across the Lake Huron basin.

&&

.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
Lake Huron...NONE.
Lake St Clair...NONE.
Michigan waters of Lake Erie...NONE.
&&

$$

AVIATION.....SC
DISCUSSION...KK/AM
MARINE.......IRL


You can obtain your latest National Weather Service forecasts online
at www.weather.gov/detroit.



Area Forecast Discussion

National Weather Service Hastings NE

 645 PM CDT Wed Jul 24 2019

.SHORT TERM...(This evening through Thursday)
Issued at 400 PM CDT Wed Jul 24 2019

Slight chance for t-storms tonight into Thursday is main forecast
concern in the short term.

It`s another pleasant summer afternoon across the CWA with
temperatures in the upper 70s to 80s for most, under sunny to
mostly sunny skies. There are a few 90s across the far SW. Dew
points remain seasonably low in the 50s to low 60s. Morning upper
air analysis along with recent water vapor still reveal a highly
amplified upper flow pattern across the CONUS, with troughing over
the E and ridging over the 4-Corners extending northward into the
N Rockies. In fact, H3 flow at OAX and LBF was nearly meridional.
A potent upper low has progressed into SW Canada. A weak mid
level perturbation is noted over N WY and the SW Canada upper low
will help eject this wave over top the ridge then SE through the
area tonight into Thu.

We will continue to see dry and pleasant conditions this eve, with
ongoing breezy conditions relaxing some near sunset. Will likely
see scat tstms dev over the Front Range and adjacent central High
Plains this eve, then move E, aided by the mid level wave and a
35-45kt LLJ. Last several runs of the HRRR bring this activity
into far W/NW portions of the CWA around 09-10Z. The LLJ will veer
toward sunrise, but point forecast soundings indicate much of the
moisture/weak instability is rooted above any lift from the LLJ
this far E, closer to the H65-H7 layer. Thus, think most of this
activity will be driven by weak isentropic ascent around the 315K
layer and the weak wave. Expanded the POPs a bit S/SE compared to
last forecast, especially during the Thu AM time frame. Do not
expect Thu to be a washout by any means, but model trends and
pattern recognition suggests we could have broken ACCAS and iso to
widely scat shwrs/weak tstms around for much of the day with
spotty rain amnts generally .1-.2" or less.

The clds will probably hamper the warmup for one more day, which
is fine by this forecaster! Continued Srly flow and warmer start
to the day should still yield widespread 80s, with some low 90s
for Phillips and Rooks Co.


.LONG TERM...(Thursday night through Wednesday)
Issued at 400 PM CDT Wed Jul 24 2019

Warmer temperatures then potential for t-storms Sun are main
forecast concerns.

The aforementioned SW Canada trough will swing E through south
central Canada Thu night into Fri. This will temporarily flatten
the western ridge but also drag the low level thermal ridge a bit
further E for Fri. Expect a 2-4C incr in H85 temps from Thu to Fri
which should yield Fri aftn highs in the upper 80s to upper 90s.
Upper heights incr and the lee trough deepens on Sat which will
promote H85 incr another couple of deg. Sat continues to look like
the warmest day of the next 7. Expect widespread 90s with some low
100s possible over the S and W. The forecast continues to be dry
Thu night-Sat, though will need to monitor for an iso elevated
t-storm Thu night with lingering elevated instability.

A cold front will approach the area on Sun from the NW. However,
the upper low responsible for the front will be weakening and
moving E across the Great Lakes, so there will not be much upper
support for this front to work with. Not surprisingly, models are
somewhat scant with pcpn chances for the local area with this
frontal passage. Nonetheless, some moisture convergence and
cooling mid-level temps could support some convection along and
behind the front. Currently have only 20-30% POPs Sun into Sun
night. Incr clds should lead to cooler temps Sun for NE zones,
but expect another warm day for KS zones in the mid to upper 90s.

Will see a brief cool down to near or slightly below normal temps
on Mon before a warming trend develops for Tue as the upper ridge
edges E and expands once again. Latest EC suggests middle of next
week could be quite warm. So, overall, a fairly typical
summertime pattern with warm temps and only a few pcpn chcs.

&&

.AVIATION...(For the 00Z KGRI/KEAR TAFS through 00Z Thursday)
Issued at 645 PM CDT Wed Jul 24 2019

Significant Wx: LLWS at EAR for a few hrs tonight.

Tonight: VFR with no clds at or below (AOB) 10K ft. S-SE winds
10-15 kt. LLWS dvlps at EAR 08Z-11Z. Confidence: High

Thu: VFR with CIGs 9-10K ft. Could see a few sprinkles or a brief
-SHRA at both terminals. S winds 10-20 kt with G20-25 kt.
 Confidence: High

&&

.GID WATCHES/WARNINGS/ADVISORIES...
NE...None.
KS...None.
&&

$$

SHORT TERM...Thies
LONG TERM...Thies
AVIATION...Kelley



Area Forecast Discussion

National Weather Service Pueblo CO

 330 PM MDT Wed Jul 24 2019

.SHORT TERM...(This evening through Thursday)
Issued at 241 PM MDT Wed Jul 24 2019

Scattered convection again developing over the mountains this
afternoon as upper level high pressure remains centered near the 4
corners. Main threat into the evening will be locally heavy
rainfall, with flash flooding possible over area burn scars as
storms will be very slow moving. Only a slight chance for storms
along I-25 as activity remains mainly across the mountains, although
HRRR hints at some weak cells forming along the Palmer Divide then
drifting south toward Colorado Springs after 00z. On Thursday, upper
high sinks south into NM, with steering currents becoming weak wly
across srn CO by late afternoon. This pattern should be more
favorable for convection to move off the mountains and into the I-25
corridor and adjacent plains than has been the case over the past
few days. Weak front/trough will also sink south through the plains
early Thu, with low level winds turning e-ne over most of the
eastern mountains and southeast plains behind the boundary by late
in the day. Moisture and instability will remain plentiful across
the region, and with weak upper energy rotating around the high,
should be at least some minor upward motion to aide in convective
development. Overall, parameters look favorable for fairly
widespread convection across the mountains and I-25 corridor, with
enough potential for heavy rainfall to warrant the issuance of a
flash flood watch for eastern mountains burn scars beginning noon on
Thu. Severe threat looks rather low given weak shear, though with
boundary in the area and CAPE running over 1000 J/KG, some brief
mainly pulse severe storms may be possible.

.LONG TERM...(Thursday night through Wednesday)
Issued at 241 PM MDT Wed Jul 24 2019

Models continue to be in good agreement through the extended
period with ensemble spreads improving over the past couple of
cycles. This leads to increased forecast confidence through the
extended period.

Thursday into Friday...expect ongoing showers and thunderstorms
across the region on Thursday as an upper disturbance passes
over north central Colorado and into the Eastern Plains overnight.
Locally heavy rainfall and flash flooding are all possible with
stronger storms, especially on area burn scars. As storms shift
east across the Plains, gusty outflow winds to near 45 mph and
small hail will also be possible. As we head into Friday morning,
models in good agreement with activity dissipating and shifting
south and east of the area.

On Friday, the upper level high is forecast to retrograde into
southern California. This will limit shower and thunderstorm
activity to mainly the Continental Divide, with the best coverage
over the San Juan and southern Sangre de Cristo ranges. Lack of
flow aloft should help keep movement limited to drifting
southward. If one of the stronger storms happens to move over a
burn scar, flash flooding may be possible. As for the Plains, they
will likely remain dry Friday evening and overnight.

Saturday and Sunday...as the upper high moves into Southern
California, flow aloft will transition northwesterly. An upper
shortwave trough is forecast to moves east out of the Northern
Rockies on Saturday and into the Plains on Sunday. Expect an
increase in shower and thunderstorm coverage on Saturday
afternoon, especially over the mountains. Storms will likely move
off to the southeast and into the I-25 corridor before dissipating
overnight. A cold front is forecast to drop south late Saturday
night into Sunday morning with increased low level moisture and
low level upslope flow from the northeast behind the front. Given
the increase in moisture and upslope flow, prolonged periods of
locally moderate to heavy rainfall will be possible, especially
over the Eastern Mountains. This may also lead to much elevated
flash flood potential Sunday afternoon and evening on area burn
scars. This will need to be monitored closely. Storms are forecast
to shift east and dissipate during the evening hours.

Monday through Wednesday...the high pressure is forecast to move
back east into the Four Corners region early next week. Models
have come in drier for Monday and Tuesday and heights rise and
drier air works into the area. There will likely be an uptick on
Tuesday over the mountains with isolated to scattered showers and
thunderstorms. Temperatures will also climb Monday and Tuesday
with mid to upper 90s across the lower elevations. By Wednesday,
energy will work its way north under the ridge and bring another
period of increased shower and thunderstorm coverage into the
middle of the work week.  Mozley

&&

.AVIATION...(For the 00Z TAFS through 00Z Thursday evening)
Issued at 241 PM MDT Wed Jul 24 2019

VFR conditions expected at all taf sites the next 24 hrs.
Thunderstorms over the mountains this afternoon will drift toward
lower elevations this evening, and will keep a VCTS at KALS and KCOS
22z-03z where some weakening convection is possible.  Storms
diminish after sunset, with clearing skies overnight. Weak cold
front and increased moisture will lead to more widespread
thunderstorm activity on Thursday, with storms impacting all
terminals during the afternoon and evening.

&&

.PUB WATCHES/WARNINGS/ADVISORIES...
Flash Flood Watch from Thursday afternoon through Thursday
evening for COZ072>075-079-080-087.

&&

$$

SHORT TERM...PETERSEN
LONG TERM...MOZLEY
AVIATION...PETERSEN