Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 07/17/20
Area Forecast Discussion
National Weather Service Amarillo TX
624 PM CDT Thu Jul 16 2020
.AVIATION...
VFR conditions are expected throughout the 00Z TAF period. Winds
will be out of the south and southwest at 10-15 kts with some
gusts near 20 kts at times, especially past 18Z Friday. Some mid
to high clouds at times, but fair weather conditions are expected.
&&
.PREV DISCUSSION... /Issued 304 PM CDT Thu Jul 16 2020/
SHORT TERM...Tonight through Friday Night...
Looking at satellite, we can detect the mid-level shortwave across
CO and NM that is firing off storms. With surface flow from the
southeast and mid-level steering flow from the west, storms are
moving northeasterly across New Mexico. Short range and hi-res
models are not certain if these storms will move close enough to
cross over the forecast area. The NAM and the HRRR want to bring
storms across Cimarron County between 6 PM and midnight but other
models keep it just out of our area. The HRRR presents meager
instability of only around 600 J/kg of ML CAPE but the NAM wants
to throw over 2000 J/kg at it. The discrepancy continues in
available DCAPE, but they do agree that there will be minimal
shear, so most likely we will only see general thunderstorms if
they do cross our area, but can`t rule out the possibility of a
storm becoming more intense and having some large hail and
damaging winds.
Temps will soar back to close to or over 100 degrees tomorrow as
surface and low level winds become more southwesterly and bring
more WAA to the area with heating from downsloping. We will likely
need a Heat Advisory for Palo Duro Canyon as temps are expected to
reach 107. Another shortwave is expected to create storms in NM
tomorrow afternoon which may affect the northwest portions of the
area. Forecast soundings are not that excited for instability in
the area tomorrow so if we do see storms, they are expected to
stay below severe limits.
Beat
LONG TERM...Saturday through Wednesday...
An upper level high pressure system stretches across the entire
southern CONUS with heights around 591mb to 594mb. The elongated
high will begin to split Saturday and the western portion will
center over the Four Corners Region with northwest flow aloft for
the forecast area. At 850mb, winds are expected to be from the
south southwest through the extended period as several disturbance
form off the Rockies. Every night from Saturday through Wednesday,
there is a low level jet present at 850mb with 25 to 35 knot
winds.
Thunderstorms are possible every evening through the
extended across the northwest half of the combined Panhandles.
Storms are likely to fire off the higher terrain and along trough
axes associated with the lee side lows forming off the Rockies.
Severe weather cannot be ruled out at this time, especially in the
far northwest Panhandles where the environment is slight more
unstable with higher MLCAPE values paired with meager effective
shear. Sunday and Monday evening have a greater potential for
strong to severe thunderstorms across the northwest half of the
Panhandles with a decent 700mb theta-e axis setting up both days.
Hot temperatures will continue through the extended period with
the hottest day being Saturday as highs will reach the upper 90s
to 108. The remaining days will be in the 90s to around 104. Low
temperatures will be in the upper 60s to 70s through the extended.
Rutt
&&
.AMA Watches/Warnings/Advisories...
TX...None.
OK...None.
&&
$$
29/88
Area Forecast Discussion
National Weather Service Dodge City KS
707 PM CDT Thu Jul 16 2020
...Update for Convective Activity...
.UPDATE...
Issued at 652 PM CDT Thu Jul 16 2020
Convective activity in eastern CO has struggled to mature over the
last several hours with the exception of one cluster of sub-severe
thunderstorms that has formed in far southeast CO/northeast NM.
This cluster is expected to continue moving northeast and enter
the western KS counties in the next 1-2 hours. Most CAMs kill this
convection shortly after it enters KS, but some indicate potential
for a weak cluster/MCS to propagate ENE just N of U.S. Highway 50
in the 03-09Z time frame. Given modest low level and deep layer
shear, severe weather is not expected. However, MLCAPE of
1000-2000 J/Kg could support small hail and locally heavy
rainfall. Gusty winds are possible as well owing to pressure
perturbations within the outflow.
&&
.SHORT TERM...(This evening through Friday)
Issued at 312 PM CDT Thu Jul 16 2020
The mid level temperatures are not as capped as recent days, +12C at
700 mb this on the Dodge City sounding. There is still very
noticeable variability in the CAMs output. In particular the the NMM
drives the late afternoon isolated eastern Colorado activity
northeast into west central Kansas counties ( Syracuse-Scott City to
Hays by midnight). By contrast the other HiRES model core clear, as
well as the HRRR clearly struggles with convective initiation
altogether n Kansas and allows the Co afternoon convection to decay
before it reaches our area of concern.
The moist dew points will keep temperatures mild overnight. Even to
coolest solutions keep the higher elevation far western counties no
cooler than the upper 60s overnight.
.LONG TERM...(Friday night through Thursday)
Issued at 312 PM CDT Thu Jul 16 2020
The atmosphere should still be conditionally unstable on Friday.
However as the day goes foreword, a dryline will develop out of the
southwest, dropping surface dew points into the 40s in the west,
relegating 60s dew points to the easternmost counties. Of the most
aggressive recent solutions in terms of convective development , the
NMM develops a cluster of storms in the evening, hinting at the area
of best boundary layer theta-e convergence. That might be a
isolated occurrence in the mid evening as there is not forcing or
reason for storms to be sustained. Saturday looks hot and dry and
potential breezy. The ECMWF shows a synoptic scale mid level trough
dropping southeast over the northern Rockies Sunday as the northern
Plains airmass is shifted farther south, setting up a zone of
moisture pooling and upslope flow from the mid Mississippi valley
into the central High Plains. This will bring the return of chances
for convection from Sunday night through early Tuesday, as well as a
slight break in the hot temperatures.
&&
.AVIATION...(For the 00Z TAFS through 00Z Friday evening) Issued
at 522 PM CDT Thu Jul 16 2020
Partly cloudy skies and light winds will bring VFR flying
conditions this TAF period for all terminals. There is a slight
chance of thunderstorms this evening and overnight, especially at
GCK and HYS in the 06-11Z time frame. However, confidence that
thunderstorms will impact any terminal is low, so I have
neglected to include any VCTS.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 70 101 76 103 / 10 0 10 0
GCK 70 101 72 102 / 20 0 10 10
EHA 68 99 71 100 / 20 10 20 0
LBL 70 103 74 103 / 0 0 10 0
HYS 70 98 75 100 / 20 0 10 0
P28 73 102 77 103 / 10 0 0 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...Springer
SHORT TERM...Russell
LONG TERM...Russell
AVIATION...Springer
Area Forecast Discussion
National Weather Service Wichita KS
617 PM CDT Thu Jul 16 2020
.SHORT TERM...(This evening through Sunday night)
Issued at 258 PM CDT Thu Jul 16 2020
The remnants of the the SE KS storm complex are making progress into
SW MO at this time. The Meso Induced Vort center (MCV) associated
with this system lags a little behind the main rain shield, over SE
KS. Most locations of southern and southeast KS look to be "worked
over" from the earlier convection, and current RAP instability progs
show this with an instability minimum over SE KS at this time. So
even with the MCV still over SE KS, think any renewed convective
chances will probably end up being over extreme SE KS, SW MO and
NE OK. Plan on leaving a small pop in SE KS for any lingering
showers, but think this chance will end late this afternoon or
early this evening.
For the rest of the night, moisture transport will again increase
across wrn KS late tonight, with showers and storms developing over
the high plains, and eventually shifting over portions of central KS
late tonight through early on Fri. This warm advection could also
lead to additional elevated showers and storms developing across
central KS and possibly SE KS with most of this activity moving
northeast of the area by early Fri.
Hot and breezy conditions will be the story for the daytime hours on
Fri and Sat, as the zonal flow leads to warm southwesterly flow
across the plains. The good downslope flow will lead to max temps
flirting with the century mark for both Fri and Sat. Surface
dewpoints still in the lower 70s across the eastern half of KS will
lead to heat index values of climbing to 103 to 106. So with
collaboration with offices to the east have decided to go with a
heat advisory for areas along and east of Interstate 135 for Fri
through Sat. Sat looks like the most sultry day of the weekend with
the highest combination of max temps and 72-75 degree dewpoints.
Could see some high plains storm chances move across Neb late Sat
night, possibly clipping portions of central KS. So will leave a
small pop in for this chance.
Highs plains storm chances look to increase by the end of the
weekend as low level moisture returns. Some of this activity will
propagate back into portions of central KS for Sun night through
Mon.
Ketcham
.LONG TERM...(Monday through Thursday)
Issued at 258 PM CDT Thu Jul 16 2020
Both the GFS and ECMWF suggest an unsettled weather pattern will
settle over the area for Mon night through Wed, as a weak frontal
boundary is expected to sag across the forecast area for the middle
of the week.
Ketcham
&&
.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
Issued at 615 PM CDT Thu Jul 16 2020
VFR conditions are forecast at all sites throughout the period.
Chances for convection appear to considerably lower than the past
few days. While not zero, there is still a small but too low to
mention chance per NAM/RAP at KRSL/KGBD and less likely chance
at KHUT/KSLN for remnants of High Plains convection from about
12-15 UTC. Otherwise increasing surface pressure gradient suggest
gusty winds developing at most sites by afternoon. -Howerton
&&
.PRELIMINARY POINT TEMPS/POPS...
Wichita-KICT 75 99 78 101 / 10 0 0 0
Hutchinson 72 97 76 100 / 10 0 0 0
Newton 72 97 76 100 / 10 0 10 0
ElDorado 72 96 75 98 / 10 0 0 0
Winfield-KWLD 73 99 76 99 / 10 0 0 0
Russell 71 97 75 101 / 20 0 10 10
Great Bend 71 98 75 101 / 20 0 10 0
Salina 72 97 78 102 / 10 10 10 0
McPherson 72 96 76 100 / 10 0 10 0
Coffeyville 74 96 76 95 / 20 0 0 0
Chanute 73 96 76 96 / 20 10 0 0
Iola 72 96 76 97 / 20 10 0 0
Parsons-KPPF 74 95 76 96 / 20 10 0 0
&&
.ICT WATCHES/WARNINGS/ADVISORIES...
Heat Advisory from noon Friday to 8 PM CDT Saturday for KSZ049-
051>053-068>072-083-092>096-098>100.
&&
$$
SHORT TERM...Ketcham
LONG TERM...Ketcham
AVIATION...PJH
Area Forecast Discussion...UPDATED
National Weather Service Memphis TN
953 PM CDT Thu Jul 16 2020
.UPDATE...
Showers and thunderstorms ended over the Midsouth earlier this
evening. CAM output is mixed for tonight with respect to
additional storm chances. GOES water vapor imagery suggests a
possible weak MCV from earlier storms over the Midsouth. This
feature alone likely wouldn`t be sufficient for additional storms
in the absence of heating, and weak overall shear. Overnight
forecast reflects a more conservative HRRR depiction. Where storms
don`t form and veil of cirrus thins, patchy fog could develop.
PWB
&&
.PREV DISCUSSION... /issued 706 PM CDT Thu Jul 16 2020/
UPDATE...
See the 00Z aviation discussion below.
PREV DISCUSSION... /issued 209 PM CDT Thu Jul 16 2020/
SHORT TERM (Tonight through Friday)...
Indeed storms proximal to the surface boundary are ongoing and
expected into the evening hours. Localized heavy rainfall and a
gusty wind are the main byproducts.
The heat index values above 105 are not quite as widespread as
thought going into today. The convection has had impact and dew
points are a bit lower as well in a number of spots. The advisory
will expire at 7 am LT. Speaking of heat advisory, have considered
the possibility of issuing for Friday, however will hold off for now
as forecast readings are largely just below 105. Thus, will allow
later shifts to better pinpoint areas and assess confidence in
making criteria.
Additionally, thunderstorms again will threaten on Friday with a
diurnal flavor. This may too have an impact on our heat index
topping out above 105.
Belles
LONG TERM...(Friday night through Thursday)...
The upper ridge is boss across the region this forecast period. Hot
and humid with diurnal convection is generally our lot in life
for the next week. There are some exceptions as a weak trough
slips by the from late Tuesday into early Thursday. This may
increase the coverage of the convection for our area and
potentially knock back temps a shade.
Belles
&&
.AVIATION... 00Z TAFS
Diminishing showers and clearing skies can be expected overnight.
Winds will remain less than 5 kts and from the south at all
sites. There is some concern that fog may form at MKL or JBR, but
confidence is too low to add to the TAF at this time.
Scattered storm coverage is expected again on Friday, warranting
a VCTS at MEM, MKL, and JBR by late morning. Activity should
diminish again near sundown.
AC3
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...None.
MO...None.
MS...None.
TN...None.
&&
$$
Area Forecast Discussion
National Weather Service Phoenix AZ
432 PM MST Thu Jul 16 2020
.UPDATE...Updated Aviation Discussion.
&&
.SYNOPSIS...
Above normal temperatures are forecast at least through
the weekend with daily lower desert highs around 110 degrees. Day to
day thunderstorm chances will continue across the eastern Arizona
high terrain through the weekend before a likely increase in
moisture by the middle of next week spreads the thunderstorm chances
westward into the lower deserts. As rain chances increase next week,
temperatures are forecast to eventually drop back to around normal
levels.
$$
DISCUSSION...
Early afternoon radar showed another round of scattered rain
showers and embedded thunderstorms from E central AZ to and along
the Mogollon rim associated with a small UL vort max, with more
isolated thunderstorms across SE AZ. Some mostly light to moderate
showers were also across NE Maricopa and S. Gila Cty around the
Bush fire burn scar. This activity was moving north along the
favored moisture and instability axis on the E AZ western flank of
the UL high still centered over TX. The 12Z Phx sounding had
moistened up to 1.27" PW and a mean W near 9 gm/kg with an even
mixture of SE to SW flow aloft. Upper air analysis confirms the
southerly component flow aloft through H5.
While struggling a bit, the HREF CAMs remain in good agreement on
keeping this afternoon`s and evening`s storm activity confined to
scattered to isolated activity SE-E and NE AZ more isolated
activity S of the Phoenix area, very much like most of yesterday`s
activity. For tomorrow`s storms some members including the HRRR
are suggesting the coverage spreading slightly farther west with
some convection possible in SW Maricopa and/or Pinal county with a
chance of some isolated storms cropping up briefly in the Phx
valley during the evening hours Friday night. However chances in
the Valley still remain low and less than 10 percent.
This evening there is again a slight chance of gusty storm outflow
winds and blowing dust with this afternoon`s and evening`s storms to
the E and SE, although similar to yesterday the activity it is
generally expected to be too distant to impact the Phoenix metro,
with Pinal cty being only slightly favored for blowing dust. For
tomorrow afternoon and evening there are more bullish signals for a
wider and more pronounced outflow, originating in stronger convection
around the Pima-MX border, that may have the potential to reach as
far as the S Phx Valley area.
Areas E and SE of Phoenix and the Mogollon rim will continue to be
the favored location for isolated storm development for the weekend
and next week with only minor day to day variation in the storm
paths expected. Although some models show part of the ridge
shifting over the Desert Southwest, it remains favorably
positioned to continue developing the moist easterly and
southeasterly flow and UL inverted trough tracks along it`s
southern flank with a series of them peeling north into the
region.
However it`s not until the middle of next week that an increase in
moisture, along with instability and shear begin to slowly improve
chances for storms after a possible drying trend for the first half
of next week. Although uncertainty remains on how robust the storm
activity will actually be closer to Phoenix.
Temperature will remain above normal in the 108-111 degree range for
Phoenix and 109-114 degrees out west. A cooling trend starting
Tuesday will bring temperatures back down to near or slightly below
normal by Wednesday and Thursday next week.
&&
.AVIATION...Updated at 2332Z.
South-Central Arizona including KPHX, KIWA, KSDL, and KDVT:
There are no major aviation concerns through at least Fri morning as
winds will follow typical diurnal trends at all the TAF sites.
Expect some afternoon breezes, but nothing out of the ordinary.
Thunderstorms are expected to remain east and southeast away from
the terminal areas. Although a remote threat of outflows from
distant storms during the evening and early night hours does still
exist, leaving any kind of wind shift out of the TAFs until later
this evening. Clouds will generally remain AOA 10k feet through the
TAF period with an increase in mid-level clouds late this evening.As
far as Fri is concerned, expecting a bit earlier-then-normal shift
to westerly winds around midday. Although there looks to be a better
chance for outflows from distant thunderstorms on Fri evening,
confidence is too low to include a wind shift in the TAFs at this
time.
Southeast California/Southwest Arizona including KIPL and KBLH:
There are no major aviation concerns as winds will follow typical
diurnal trends. Expect some afternoon breezes, but nothing out of
the ordinary.
&&
.FIRE WEATHER...
Saturday through Wednesday:
Modest moisture levels through the weekend will provide at least a
slight chance for showers/thunderstorms mainly over the higher
terrain north and east of Phoenix. Higher moisture levels into
next week will expand storm chances into the AZ lower deserts by
Tuesday or Wednesday. Outflow winds, even from distant storms,
will be a concern most days across eastern and possibly south-
central Arizona. Daytime RH values will be in the 10-20% range
through Monday, increasing to 15-25% starting Tuesday. Overnight
recoveries rise into the 30-50% range each day. Outside of any
thunderstorms, winds will follow diurnal/terrain driven trends
with typical afternoon breeziness.
&&
.SPOTTER INFORMATION STATEMENT...
Spotters should follow standard reporting procedures.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...None.
CA...None.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...None.
CA...None.
&&
$$
DISCUSSION...Sawtelle
AVIATION...Percha/Benedict/AD
FIRE WEATHER...Sawtelle/Kuhlman
Area Forecast Discussion
National Weather Service Pueblo CO
342 PM MDT Thu Jul 16 2020
.SHORT TERM...(This evening through Friday)
Issued at 340 PM MDT Thu Jul 16 2020
Main forecast concerns/challenges this period will remain with
shower and thunderstorm chances through this evening, and once again
on Friday. An isolated strong to severe storm will remain possible
through early this evening.
In the near term, scattered showers and storms continue to develop
across parts of southern CO. While development continues across the
higher terrain, focus has shifted a little to the east along parts
of the I-25 corridor. In these locations, have noted slightly higher
focus, with these storms developing along two separate moisture
convergence axes. Per latest RAP analysis, these are located from
Fremont county northeast to Teller and El Paso counties, and from
around Pueblo southeast to Springfield. These locations will have
the highest potential to see the highest coverage of storms for
the remainder of the afternoon into the early evening, along with an
isolated strong to severe storm. Despite forcing remaining limited,
instability remains on the higher side this afternoon with very
steep lapse rates in place, that once again will support an isolated
strong/severe storm capable of hails to the size of quarters and
wind gusts to around 60 mph. Don`t think the flash flooding threat
is high for most areas given the limited coverage, however, slow
storm movement with brief heavy downpours could support localized
minor flooding concerns. Most thunderstorm development is focusing
to the east of the burn scars and think the flash flooding risk for
area burn scars has lowered. However, can`t rule out an isolated
storm to move across the burn scars and will continue to closely
monitor. Should see any stronger development end by mid evening, but
think some isolated showers and storms will persist slightly longer
this evening.
Additional showers and thunderstorms will again be possible Friday
afternoon, though focus looks to be over the mountains. Can`t rule
out an isolated storm spilling into parts of the I-25 corridor
though, but any severe threat looks low at this time.
.LONG TERM...(Friday night through Thursday)
Issued at 340 PM MDT Thu Jul 16 2020
Friday Night and Saturday:
Ongoing convection will continue into Friday evening. The forecast
seems to be on track from yesterday with convection primarily
staying over the mountains, the Raton Mesa, and the Palmer Divide.
Some of the storms may develop over Baca County, as well. The
environment isn`t the greatest, the best instability will be over
the mountains, so the flash flooding risk will continue over the
burn scars during the evening. Over the plains, CAPE values will be
under 1000 J/kg and deep shear values will be less than 25 kts,
meaning storms that form over Baca County will be weak and
unorganized. All thunderstorm chances will dissipate shortly after
midnight.
Saturday will be similar to Friday, except there will be less shear
in the atmosphere due to weak winds aloft and weak surface winds,
therefore weak thunderstorms are expected to develop over the
mountains once again. There is a flash flood risk over the burn
scars as thunderstorms develop during the afternoon. With the
limited convection and general southwesterly flow over the region,
temperatures will be hot over the entire region. Widespread +100F
over the plains, mid to upper 80s over the mountain valleys and
Teller County, and the mid 70s over Lake County.
Sunday:
A frontal passage is expected on Sunday, but the timing and
intensity is still uncertain. Via deterministic models, the GFS is
flip-flopping between a strong frontal passage and a weak frontal
passage being stalled over the eastern plains and eventually being
overcome with westerly winds off of the mountains. Whereas the NAM
has a strong frontal passage, but the model run stops before the
potential impacts. Soundings reveal a pretty dry low-level, so even
if the front does pass over the region, it`ll be hard for
precipitation to fall. The main forecast impact of how strong the
front is will be wind speeds and temperatures.
Monday through Thursday:
The rest of the forecast will depend on the frontal intensity, but
the forecast is that Monday will be a post-frontal scenario.
Southeasterly winds will develop over the plains, sparking
thunderstorms over the mountains that may spread east over the
plains. Low CAPE values are expected so the storms will be weak.
The rest of the weak looks awfully wavy, with shortwaves
propagating over Colorado each day. Each day also looks to bring
scattered showers and thunderstorms over the mountains and the lower
elevations. The daily thunderstorms will help keep the temperatures
down as well.
&&
.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
Issued at 340 PM MDT Thu Jul 16 2020
Main forecast concerns continue to be with thunderstorms through
this evening across all of the TAF sites. Latest radar imagery is
showing an increasing coverage of showers and storms near all of the
sites, and think it`s possible for a storm to move overhead over the
next couple of hours. COS and ALS still have the highest potential,
but think there might be a slightly higher chance for PUB and will
continue to monitor trends. Thunderstorm potential lowers by mid
evening, but think there will be some scattered showers lingering
across the area later into the evening. Impacts should be low
though. VFR and dry conditions tonight into Friday morning, with
shower and thunderstorm development once again possible Friday
afternoon. Focus should remain away from the sites, but will need
to monitor for the potential of an isolated storm or two.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...RODRIGUEZ
LONG TERM...SKELLY
AVIATION...RODRIGUEZ
Area Forecast Discussion
National Weather Service Blacksburg VA
929 PM EDT Thu Jul 16 2020
.SYNOPSIS...
High pressure over the east coast and a frontal system across
the midwest will keep our area in a southerly flow through
Friday. The front enters the area late Friday and then moves
north as a warm front Saturday.
&&
.NEAR TERM /THROUGH FRIDAY/...
As of 930 PM EDT Thursday...
Ongoing isolated pulse/multicell thunderstorms will continue
for a couple more hours, bringing localized gusty winds and
very heavy rainfall. Small hail is also possible with the
strongest storms.
Adjusted POPs overnight, with highest POPs corresponding to the
ongoing activity along and just west of the Blue Ridge.
Gradually reducing the chance by morning. Areas east of the
Blue Ridge dry after midnight. Highest CAPE values remain pooled
up along and west of the Blue Ridge, with latest RAP analysis
indicating some areas in excess of 2500 j/kg. This should be
enough to keep shower/thunderstorm activity going for the next
couple of hours. NAM Nest and most recent HRRR also agree that
isolated thunderstorms will continue.
Also bumped up low temperatures a degree or two overnight.
Tropical/humid airmass will keep temperatures very mild
overnight, with lows in the upper 60s and lower 70s.
As of 130 PM EDT Thursday...
Widely scattered showers have been developing since mid-morning
mainly along and east of the Blue Ridge. Nothing very strong
or slow-moving to present water problems yet. Fairly high
instability along with high PWATS of 1.6 to 1.7
inches per mesoanalysis suggest some heavy rainers possible
but severe potential limited, although a marginal pulse severe
not out of the question. Activity should follow a diurnal trend
with weakening after sunset. Plenty of clouds and high humidity
will make for a warm overnight with mid- to upper 60s even
in the mountains and low 70s east.
Slow-moving boundary approaches tomorrow with better chances
for showers and storms. Very high PWATS approaching 2 inches
again indicate decent chances for pockets of heavy rainfall
and WPC has most of the area under Marginal Risk for excessive
rainfall. Which would be be highly beneficial in most cases (see
Hydro section below). Warm and muggy as usual.
&&
.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY NIGHT/...
As of 145 PM EDT Thursday...
A front from Friday stalls over the area overnight. Despite it being
over the region, POPs will decrease overnight with the loss of
heating. However, this front will serve as a lifting mechanism
Saturday to help re-ignite showers and thunderstorms during the day.
The greatest concentration/chances will depend on where exactly the
front stalls, which looks to be near the VA/NC boarder at the moment.
By Sunday, this stalled front will shift slightly further south with
forcing from a new upper level disturbance that will be passing to
our north. This will bring yet another weak front Sunday afternoon,
sparking the greatest POPs along the west.
Sunday`s front will stall over the region for Monday, creating a
somewhat similar repeat in forecast from Saturday, though POPs look
more likely to be widespread. The reason for thoughts on more
widespread POPs will be the ample heating Monday with guidance
suggesting that it will be the warmest day of the forecast.
Temps through the period remain above average, with Monday looking
like the warmest day of the forecast with areas east of the
mountains topping in the mid to upper 90s.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
As of 145 PM EDT Thursday...
Zonal flow will dominate the forecast through the period while
numerous upper level disturbances to our far north move through.
These disturbances will help drive numerous shortwaves into the Mid-
Atlantic. These shortwaves in turn will help drive ample chances for
afternoon showers and thunderstorms during the afternoons each day.
Temperatures will continue to remain above normal through the period.
&&
.AVIATION /02Z FRIDAY THROUGH TUESDAY/...
As of 730 PM EDT Thursday...
Highly variable environment in terms of CIGS with scattered
showers and thunderstorms tonight and also again on Friday.
Most of the activity this evening will be confined to west of
the Blue Ridge. Brief reduction in VSBY where
showers/thunderstorms occur, but overall mainly VFR conditions
will prevail during the TAF period.
The exception to the VFR conditions will be for LWB before
sunrise Friday. Fog could briefly drop LWB into IFR, however,
confidence in this occurring is low.
Extended Aviation Discussion...
Overall mainly VFR weather to continue through the weekend. We
will have uptick in storms by Saturday through Monday, so
periods of sub-VFR are possible in storms, and potential for
late night/early morning fog at LWB/BCB will increase.
&&
.HYDROLOGY...
As of 130 PM EDT Thursday...
As we reach the mid-point of July, climatologically the wettest
month of the year, the rainfall numbers are impressively
unimpressive and quite the turnaround from April through June.
Here are the July 1-15 rainfall totals (inches) and ranking
from four of the five `official` climate sites:
Bluefield `T` - driest (since 1909)
Roanoke 0.19 - 3rd driest (since 1912)
Lynchburg 0.34 - 10th driest (since 1893)
Blacksburg 0.70 - 17th driest (since 1893)
Danville has been wetter, having received several downpours.
But the bulk of the CWA has been quite dry for 3+ weeks, really
since around June 18th. Impacts are mainly in terms of rapidly
drying surface soils, browning lawns and parched gardens. But
another week of dry weather may be enough to tip the area
into recognition from the U.S. Drought Monitor.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...None.
NC...None.
WV...None.
&&
$$
SYNOPSIS...WP
NEAR TERM...BMG/PC
SHORT TERM...RR
LONG TERM...RR
AVIATION...BMG/PC
HYDROLOGY...PC
Area Forecast Discussion
National Weather Service Tucson AZ
345 PM MST Thu Jul 16 2020
.SYNOPSIS...Scattered mainly afternoon and evening thunderstorms
into next week. Expect locally heavy rainfall, gusty outflows and
patchy blowing dust at times. Daytime temperatures generally a few
degrees above normal into early next week.
&&
.DISCUSSION...Scattered showers and thunderstorms were occurring as
of this writing mainly across Cochise County, eastern Pima County
and Santa Cruz County. These showers and thunderstorms were mostly
stationary, or moving to north around 5 mph. Several outflow
boundaries were also apparent via radar imagery, with the most
notable outflow from near KEMX radar southward to near Lochiel.
Several HRRR solutions and the 16/12Z Univ of AZ WRF-GFS suggest
that showers/tstms will continue into early this evening, then
gradually dissipate after sunset. The bulk of showers/tstms should
end by midnight. However, have maintained isolated showers/tstms
late tonight mainly east to south of Tucson. Regarding the potential
for blowing dust of significance, have trended toward the U of A WRF-
GFS 10m wind depiction.
As such, have favored an area along Interstate 10 near the Willcox
Playa eastward to the New Mexico state line for patchy blowing dust
until around 8 pm MST this evening. There is the potential for some
blowing dust northwest of Tucson and along the I-10 corridor.
However, have opted to remove the inherited depiction of patchy
blowing dust given fairly low high-resolution model wind speeds this
evening.
For the period Friday through around Tuesday, the 16/12Z GFS/GEFS
and ECMWF/ECENS have a general theme of suggesting that scattered
showers and thunderstorms will occur mainly during the afternoon and
evening hours, and favor locales NE-SE-SW of Tucson. However, the
entire forecast area has at least a 10 percent chance of
showers/tstms during almost any forecast period.
Starting around Wednesday and continuing into Thursday (last day of
this forecast package, and perhaps even beyond Thursday), the global
models continue to suggest a potentially pronounced increase in
daily coverage and rainfall amounts from showers and thunderstorms.
The potential increased coverage and rainfall amounts appear to be
in response to the models depicting a deeper southeasterly flow
regime across the area.
High temperatures will generally be a few degrees above normal into
early next week, then highs moderating a few degrees later next week.
&&
.AVIATION...Valid through 18/00Z.
FEW-SCT clouds 10-15k ft MSL and SCT-BKN clouds above 20k ft MSL
through much of the period. Isolated to scattered TSRA/SHRA this
afternoon and evening near all terminals. Expect similar TSRA
activity Friday afternoon. Gusty outflow winds around 40 kts and
brief MVFR conditions may occur near the stronger TSRA. Outside of
gusty outflows, SFC winds will be WLY/SWLY 8-12 kts this afternoon.
Windspeeds diminish late this evening into Friday morning becoming
variable at less than 10 kts. Wind increase again out of the NW
Friday afternoon. Aviation discussion not updated for TAF amendments.
&&
.FIRE WEATHER...Expect isolated to scattered showers and
thunderstorms each afternoon/evening through the forecast period for
most of southeast Arizona. Daytime relative humidities will be 15-30
percent into early next week with generally good overnight
recoveries. Additional moisture may arrive by the middle of next
week resulting in higher humidity levels. 20-ft winds generally
follow diurnal patterns at less than 15 mph with some afternoon
gustiness, although any thunderstorms will be capable of producing
gusts of 45 mph or higher.
&&
.TWC WATCHES/WARNINGS/ADVISORIES...None.
&&
$$
DISCUSSION...Francis
AVIATION...Hardin
FIRE WEATHER...Hardin
Visit us on Facebook...Twitter...YouTube...and at weather.gov/Tucson
Area Forecast Discussion
National Weather Service Las Vegas NV
543 PM PDT Thu Jul 16 2020
.SYNOPSIS...Hot and dry weather will continue through early next
week with generally light winds. Monsoonal moisture may begin to
creep back into the region by the middle or end of next week, with
an uptick in cloud cover and thunderstorm activity possible.
&&
.AFTERNOON UPDATE...
With convection evident in northern Mohave County and on the crest
of the Sierra, made some modifications to the PoP/Wx/QPF grids for
those respective areas. Convection over northern Mohave hasn`t been
overly impressive as individual cells, but have been redeveloping
updrafts in the same general area north of Mount Trumbull.
Additionally, GOES-W trends show additional updraft formation
farther south along the Sierra crest. Keeping a close eye on any new
fire starts due to isolated CG lightning strikes but so far, no
evidence of this yet within the VEF CWA. HRRR trends have just about
all of this activity over with by 03Z thus trended as such in the
hourly PoP grids.
.SHORT TERM...through Sunday.
Fairly benign conditions expected through the weekend with a weak
low pressure trough off the SoCal coast while the subtropical
ridge remains anchored across the Southern Plains region. The end
result for us will be continued hot temperatures with southerly
breezes, while conditions remain rather dry as the monsoon flow
remains focused to our east. The only exception to the dryness
may be across the Sierra where daily thunderstorm chances remain
in the forecast thanks to intense surface heating and the
associated instability, as well as a slightly diffluent flow
ahead of the upper low offshore. Isolated storms will also be
possible across far eastern Mohave county closer to the deeper
monsoonal moisture, mainly on Saturday and Sunday.
.LONG TERM...Monday through Thursday.
Changes will begin to take hold in the longer term period as the
first notable monsoon push into the region continues to be
advertised for arrival sometime next week. However, forecast trends
keep nudging the arrival of this moisture later and later. Part
of the reason for the delayed timing is due to uncertainty in the
depth and location of a weak trough over central California. If
the trough remains a bit stronger, it could keep a drier westerly
component in place and delay the moisture arrival till very late
in the week. Alternatively, a weaker trough or one lingering
further offshore would allow an earlier moisture return. Ensemble
guidance lends some credence to a deeper trough, though still
attempts to bring in some monsoonal moisture Wednesday onward,
mainly along and east of I-15. In addition, this pattern could
result in a little added dynamic support for convective activity
late in the week. For now, given the uncertainties, PoPs are
limited to Northwest Arizona, but chances may get nudged westward
with time owing to model trends.
&&
.AVIATION...For McCarran...Light southeasterly winds will continue
through the remainder of the morning and into the early afternoon.
Southerly winds will increase by mid-afternoon with gusts 15-20 kts
possible. These winds will become more southwesterly and the gusts
will fall off after sunset, becoming light and variable overnight. A
similar situation expected Friday, with light southeasterly winds
prevailing through the morning and early afternoon, followed by
southerly gusts mid-afternoon through sunset. No operationally
significant cloud cover expected through the TAF period.
For the rest of southern Nevada, northwest Arizona and southeast
California...Light winds expected to continue for the remainder of
the morning and into the early morning hours before gusty southerly
winds 15-20 kts build in mid-morning. After sunset, these gusts will
fall off, becoming light and variable for most overnight, though
southerly winds around 10 kts will sustain through the overnight
hours for the Colorado River Valley TAF sites. KDAG will sustain a
westerly direction 10-15 kts through the TAF period. A similar story
expected Friday as well. No operationally significant cloud cover
expected through the TAF period.
&&
.SPOTTER INFORMATION STATEMENT...Spotters are encouraged to report
any significant weather or impacts according to standard operating
procedures.
&&
$$
UPDATE...TB3
DISCUSSION...Outler
AVIATION...Varian
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