Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 04/24/19
Area Forecast Discussion...UPDATED
National Weather Service Albuquerque NM
931 PM MDT Tue Apr 23 2019
Accumulating snowfall has ended over the higher terrain of northern
NM therefore the Winter Storm Warning has been cancelled. The next
weather element to examine will be fog and low cloud development
overnight across parts of eastern NM, particularly the Caprock area
of Roosevelt and Curry counties. The latest HRRR and RAP guidance
shows low vis developing after midnight but MOS guidance indicates
only low cigs. Will take another look prior to an 11 pm update to
see if expansion of the Dense Fog Advisory is warranted.
.PREV DISCUSSION...521 PM MDT Tue Apr 23 2019...
00Z TAF CYCLE
Another round of rain showers, a few thunderstorms and northern
mountain snow showers with widespread mountain obscurations will
continue into tonight. Some clearing will begin overnight which may
lead to IFR ceilings and fog forming. This is most likely at KLVS,
but could also occur and KSAF, KTCC and KROW. Some residual showers
and mountain snow showers will be possible tomorrow over the northern
portion of the state, otherwise dry and warmer Wednesday with VFR
.PREV DISCUSSION...322 PM MDT Tue Apr 23 2019...
Showers and thunderstorms will continue through evening. Some storms
near and south of I-40 will contain heavy rain, small hail and gusty
winds, while the high terrain of the northern mountains may see light
snow. Fog has also developed around Clines Corners and this fog may
expand overnight across the east central plains. Visibility near one
quarter mile is possible. On Wednesday through Friday, a few storms
are still possible across the high terrain during the afternoons and
evening, but coverage will be less than today. Temperatures will warm
to back above normal. However, another storm system is on tap early
A slow moving upper level low pressure system will continue to track
eastward across Mexico tonight. Diurnally driven convection has
developed this afternoon, aided by lift from both the upper low and
low level moist upslope. 90th percentile PWATS combined with modest
instability across southern NM thanks to breaks in the clouds, have
allowed for both small hail and heavy rainfall in the stronger
storms. Once the sun sets, and the trough axis shifts over eastern NM
after midnight, storm coverage will decrease significantly. A slight
chance for persistent storms will remain possible across the far
southeast portion of the CWA north of the stalled frontal boundary.
However, it is believed that most of the precip will remain south of
Chaves County. Meanwhile, fog has developed near Clines Corners and
this will likely continue, if not expand overnight across much of the
east central plains. Have issued a Dense fog advisory for Clines
Corners, which again, may be expanded later tonight.
Recycled moisture and daytime heating will allow for enough
instability for a few storms to develop across the higher terrain on
Wednesday. Coverage will decrease significantly from today, and storm
motions will be toward the south. An upper level ridge will move
over the Desert Southwest on Thursday while a weak back door front
nudges into northeast NM. Still, the moisture will not be entirely
scoured out, thus, a few more storms will be possible across the high
terrain. The Sangre de Cristo Mountains will be favored as the low
level upslope flow behind the front will help focus storm
On Friday, the ridge will flatten some, and allow westerly winds to
increase. The NAM is suggesting that a little convection may develop
over the high terrain and shift eastward. Since it will be somewhat
drier, should storms develop, some dry lightning would be possible.
Another front will nudge into northeast NM on Saturday, and the GFS
is bullish with regards to QPF across NE NM behind the front. That
said, the GFS also shows the front continuing south and westward into
Sunday, while the ECMWF largely has the front washing out. This front
is the beginning of some large discrepancies in the extended. As the
surface winds veer around to the south, the GFS brings up Gulf
moisture into the eastern plains on Sunday, but the ECMWF is drier
with westerly winds until it has a front of it`s own early Monday.
Both models show the next storm system moving toward the Four
Corners Monday night and crossing Tuesday, though the ECMWF is
slightly slower. The slower ECMWF draws up much more Gulf moisture,
adding to the potential for more wetting rains across eastern NM,
while the GFS is faster and brings more wind to the state.
A wetting event continues as the Pacific low turns east across
northern Mexico, although wetting precipitation is becoming more
isolated as the the atmosphere becomes increasingly convective this
afternoon. Solid wetting precipitation noted from the overnight and
early morning hours across much of central and eastern New Mexico.
Precipitation will diminish after midnight as the upper low pulls
further southeast toward far west Texas.
A warming/drying trend will begin Wednesday and continue into the
weekend as a broad upper level ridge gradually shifts east over the
region. However, sufficient moisture will remain for limited rounds
of showers and storms each afternoon/evening over the higher
terrain. The westerlies will begin to trend up Friday afternoon as
the ridge flattens, along with Haines indices and the potential for
dry lightning given limited remaining moisture and a drier lower
boundary layer. The potential for critical fire weather conditions
will trend up over the weekend and into Monday in advance of another
Pacific low approaching from over southern California. However, fire
growth potential may be significantly limited by recent wetting
precipitation and green-up.
Dense Fog Advisory until 9 AM MDT Wednesday for the following
AREA FORECAST DISCUSSION
National Weather Service Burlington VT
730 PM EDT Tue Apr 23 2019
After another sunny day across the North Country, cloud cover will
build back into the region this evening. A cold front will sweep
through the region during the overnight hours with widespread
rainfall amounts ranging from a quarter to a third of an inch. Rain
showers will continue behind the front on Wednesday but will likely
be confined to the higher terrain. Showers will then taper off
Wednesday evening with drier conditions expected to continue through
Friday morning before another cold front approaches the region from
.NEAR TERM /THROUGH WEDNESDAY NIGHT/...
As of 730 PM EDT Tuesday...Going forecast is in great shape
with only a slight tweak needed to precip onset and end timing.
Showers are moving into western portions of the CWA currently
and latest trends show the bulk should clear northern New York
during the 03-05Z hours and eastward across Vermont from 06-09Z.
Some question with the latest 18Z guidance as to how much
upslope precipitation develops after 09Z, but have left the
forecast intact for now and will assess the upcoming 00Z
guidance for any potential changes. Other change was to remove
mention of any thunder as this afternoons activity has all but
gone away with no convection noted in the upstream obs/radar.
Previous Discussion...Skies cleared nicely throughout the day
with the axis of mid-level ridging moving across the North Country.
The subsidence can be seen nicely on satellite imagery and even
continues to suppress any cumulus from forming given temperatures
once again in the mid 60s to near 80 degrees. RAP soundings suggest
100 to 400 J/kg of CAPE yet CIN of -50 to -70 J/kg hints at why
diurnal cumulus has been hard to come by. That all will change
tonight as rather dynamic shortwave interacts with a developing
upper level low tracking across the international border. Convection
with this system can already be seen across western New York and
western Pennsylvania and all CAMs show the system entering a more
"energetic" air mass that hasn`t been capped by cloud cover.
As this happens, the frontal boundary associated with the upper
level trough will begin to pick up some speed and develop additional
convection as it crosses New York. While there is some CIN in place,
it looks like the front will be able to lift surface parcels above
the subsidence inversion and allow for some convective showers and
maybe even a thunderstorm or two to track into northern New York
after sunset. The loss of diurnal heating will limit convection
heading into the overnight period across Vermont but enough mid-
level forcing should still allow for convective showers to continue,
albeit a near nil chance for thunderstorms. Overall rainfall amounts
through tonight will be widespread quarter to a third of an inch of
As the upper level low tracks eastward toward Newfoundland, recycled
Atlantic moisture will wrap around the low and move back into the
North Country. In addition, with cold air advection behind the low,
we will see in increase in mid-level lapse rates which will help
produce additional showers on Wednesday; especially during the
morning and afternoon hours. The majority of these showers will fall
on the western slopes of the Adirondack and Green Mountains with
Froude numbers near 1. Some showers could back build throughout the
day into the Champlain Valley but most rainfall accumulations will
be restricted to the western slopes where an additional tenth to
quarter of an inch of rainfall will be possible. This rain won`t be
enough to cause any significant impacts on area rivers as levels
have dropped nicely after the two precious heavy rain events.
.SHORT TERM /THURSDAY THROUGH THURSDAY NIGHT/...
As of 318 PM EDT Tuesday...Weak default ridging then builds
briefly across the area during Thursday with partly sunny skies,
light winds and seasonal temperatures from the upper 50s to mid
60s. Should be a really nice day for outdoor activities. By
Thursday night our next system in the pipeline approaches with
moisture streaming northeastward ahead of a sharply digging
upper trough across the Great Lakes. The idea of thickening
clouds later at night with increasing chances for showers across
the southwestern half of the forecast area toward morning looks
reasonable for now. This morning`s QPF/mass fields from the GFS
seem overdone at this point and as such have largely ignored
its output. Low temperatures to range from the upper 30s to mid
40s, slightly cooler far northeast where partial clearing will
persist most of the night.
.LONG TERM /FRIDAY THROUGH TUESDAY/...
As of 318 PM EDT Tuesday...Much uncertainty exists in the
extended portions of the forecast in regard to chances of
rainfall. Complicating matters will be persistent and fast semi-
zonal flow north of 40N at and above 500 mb which typically
leads to large model spread in timing/strength of systems. Today
is no exception with the GFS and Euro at odds with one another
during much of the period and at times 180 degrees out of phase.
For the sake of simplicity have downplayed pops into the lower
probability ranges, especially from Sunday onward until more
consistency is realized. The most confidence thus lies during
the front end of this period (Friday/Friday night) when the
aforementioned shortwave swings through the region with
scattered/numerous showers. Otherwise the main theme for now
with be variable clouds with on and off periods of partial
clearing with temperatures averaging near or slightly below
normal (mainly 50s and 30s).
.AVIATION /00Z WEDNESDAY THROUGH SUNDAY/...
Through 00Z Thursday...Conditions will be deteriorating
overnight from VFR currently to MVFR this evening and through
the much of TAF period with isolated IFR possible at KSLK and
KMSS. Showers will shift across the area from 00-09Z with
additional upslope showers possible at KSLK after 12Z.
Restrictions in flight category will primarily be due to
ceilings, but in some heavier showers brief MVFR visibilities
are possible. Variable winds will shift to the south/southwest
this evening and eventually west/southwest overnight with gusty
winds to 25 knots possible Wednesday morning and afternoon.
Wednesday Night: Mainly VFR, with local MVFR possible. Chance
Thursday: VFR. NO SIG WX.
Thursday Night: VFR. Slight chance SHRA.
Friday: Mainly VFR, with areas MVFR possible. Definite SHRA.
Friday Night: Mainly VFR, with areas MVFR possible. Likely SHRA.
Saturday: Mainly VFR, with areas MVFR possible. Chance SHRA.
Saturday Night: VFR. Slight chance SHRA.
Sunday: Mainly VFR, with local MVFR possible. Chance SHRA.
Area Forecast Discussion
National Weather Service Austin/San Antonio TX
1057 PM CDT Tue Apr 23 2019
.UPDATE.../SVR WATCH VAL VERDE COUNTY EXPIRES AT 11/
Predictably, the late afternoon runs of the HRRR were too aggressive
with the Burro Mountain convective complex, and the mid evening runs
displayed a more isolated picture for convection to roll off the
higher terrain into the southern Edwards Plateau and western Hill
Country in the early morning hours. Severe threat remains the same,
only the likelihood of deep convection is lower due to current
capping. This should weaken closer to daybreak, so will maintain the
status quo on the 1 am - 7 am PoP grids, knowing the areas SE of the
escarpment should see a lower coverage a deeper convection.
A view of the mesoscale models versus the synoptic models offer two
scenarios for heavy rain areas, and we are gaining confidence for a
secondary precipitation maxima located over the eastern Hill Country
for late Wednesday afternoon/Wednesday evening. This would assume the
frontal/outflow boundaries from the overnight convection hangs up
north of the CWA through daybreak. The pattern continues to suggest
pockets of 4-6 inches is possible.
.PREV DISCUSSION... /ISSUED 746 PM CDT Tue Apr 23 2019/
Afternoon heating generated some scattered showers with tops to
around 15 kft but showed no signs of breaking the cap. DRT 00z
soundings arrived with a formidable cap at 8-10 kft, so expect no
threat of evening storms forming in the eastern Hill Country and
I-35 corridor counties. Updated to remove thunder for the evening for
those areas. An approaching jet streak exit region late tonight
could signal deeper convection chances ramping up after midnight west
of DRT. While there does seem to be a slight radar increase trend to
the distant SW, do not expect the past couple runs of the HRRR to
verify with their depiction of a small complex moving as far east at
Hwy 83. More isolated activity firing off the higher terrain and
crossing the Rio Grande is what the consensus of models and even
earlier HRRR runs have been saying. Watch to remain in effect for
DRT, but likely any storms that impact Val Verde will be after the
watch expires at 11 pm. Will plan to keep the watch running in case a
time extension is needed.
PREV DISCUSSION... /ISSUED 647 PM CDT Tue Apr 23 2019/
Most of the region has VFR ceilings as this new TAF period begins.
The exception is SAT where it is MVFR. There are isolated showers
across the area and some showers may move across any of the airports
this evening. This will not reduce the flying category. Ceilings will
lower later tonight eventually reaching IFR overnight. Chance for
showers and thunderstorms will continue overnight. At DRT the best
chance for thunderstorms will be late overnight. Thunderstorms will
reduce visibility and bring strong wind gusts. Hail is also possible
in storms. The best chance for thunderstorms in Austin and San
Antonio will be late afternoon Wednesday. There is a slight chance
that thunderstorms will bring severe hail (>1") or wind gusts
(>50kts). The probability that any severe thunderstorm hits any
airport is very low and we have not included this in the TAFs.
Weather should improve after a cold front moves through the area
Wednesday afternoon or early evening. Winds will shift to the north
and ceilings will lift to VFR.
PREV DISCUSSION... /ISSUED 354 PM CDT Tue Apr 23 2019/
SHORT TERM (Tonight through Wednesday Night)...
An active short term forecast is expected for South Central Texas.
For tonight, Severe Thunderstorm Watch 95 is in effect for Val Verde
County through 11 PM CDT. Visible satellite imagery has shown nearly
persistent cloud cover across Val Verde County through the day, which
has helped limit overall destabilization, but nearly full insolation
along the Serranias del Burro have resulted in an agitated cumulus
field with the DRT radar showing developing showers. SPC Mesoanalysis
shows over 50 knots of southwesterly effective bulk shear,
encouraging additional thunderstorm organization. As these
thunderstorms become more organized, convection allowing models
indicate that these storms will make a run for the Rio Grande later
this evening. Despite the cloud cover, dew points in the upper 60s
are contributing to SBCAPEs in excess of 2500 J/kg which will help
storms maintain themselves as they approach the Rio Grande. This
will also allow them to advantage of steeper mid-level lapse rates
of 7 C/km and encourage a large hail threat for parts of Val Verde.
Farther north, convection continues to fire along a frontal boundary
draped roughly along Interstate 20. Higher resolution guidance has
been fairly consistent in advertising strong enough cold pool
development with these thunderstorms that the cold front may actually
be driven farther south than global guidance indicates by sunrise
(into Central Texas/the Hill Country). Should this happen, this will
set up the potential for training showers and thunderstorms as
increasing forcing from an upper low diving across Chihuahua tonight
into the Big Bend arrives. For the remainder of tonight, expect most
of the shower and thunderstorm activity to remain relegated to the
northern tier of counties with rainfall amounts up to one inch
During the day Wednesday, the location of the aforementioned frontal
boundary will have huge implications for which areas see the heaviest
rainfall but expect the frontal boundary to be near the northern
border of the forecast area. The approach of the upper low will allow
for the left front quadrant of an upper level jet to nose into
Central Texas. While the initial approach of this upper level jet is
expected to be during the morning hours (usually the most stable time
of the day), increasing divergence aloft will help to accelerate rain
rates across portions of Central Texas and the Hill Country. With
forecast precipitable water values rising to near 1.5 inches,
enhanced lift, and a slow-moving frontal boundary, have concerns that
a localized flash flood threat may materialize for parts of the
eastern Hill Country into Central Texas and have issued a Flash Flood
Watch through the day Wednesday as a result. Current expectations
for rainfall amounts in the watch area are in the 2 to 4 inch range,
but isolated higher amounts in the 4 to 6 inch range appear possible
based on ensemble plumes and high resolution QPF output. Based on
these forecast amounts, rises to at least action stage on rivers and
creeks are also possible during the day Wednesday.
Despite persistent cloud cover during the day, at least some
destabilization during the peak of the diurnal cycle and strong
forcing for ascent will allow for some thunderstorm intensification
during the afternoon hours. Cannot rule out some large hail, but
expect gusty winds to be the main concern with freezing levels above
12,000 feet AGL and updrafts becoming water loaded as the
thunderstorms translate east. Backed surface flow in the vicinity of
the cold front may also create for an isolated tornado threat.
Analysis of dProg/dt trends during the evening hours show the upper
low beginning to accelerate away from the region and expect the flash
flood and severe threat to taper off during the evening as the main
system translates away from the region. A few showers and
thunderstorms may linger Wednesday night as the system moves farther
LONG TERM (Thursday through Tuesday)...
The front and associated rain push out of the area by early Thursday
morning, leaving the region in a NW flow. A gradual dry and warming
period takes hold. As the subsequent surface high tails the front,
winds will veer to a SE flow early Saturday.
Broad ridging over the central CONUS will struggle to build over the
weekend due to an embedded stream feature resulting in zonal flow
aloft. The GFS is an outlier with handling this feature by deepening
it as it moves over the Northern Plains and Midwest, then tries to
bring a backdoor front into the region on Sunday. If this scenario
proves true, limited moisture return to over the area would only
result in a minimal amount of rain even if the forcing makes it to
The warmest day of the forecast look to be either Sunday or Monday
with highs for I-35 sites reaching the mid to upper 80`s and mid 90`s
out west. With persistent SE flow for most of the long term period,
clouds return over the area by Monday with the possibility of
streamer showers developing on Tuesday.
.PRELIMINARY POINT TEMPS/POPS...
Austin Camp Mabry 66 74 59 78 60 / 50 100 90 20 10
Austin Bergstrom Intl Airport 65 74 59 78 60 / 50 100 90 20 10
New Braunfels Muni Airport 65 75 58 79 59 / 50 90 90 10 0
Burnet Muni Airport 64 70 57 75 58 / 50 100 70 20 10
Del Rio Intl Airport 66 80 58 86 60 / 60 80 20 0 0
Georgetown Muni Airport 64 72 58 76 59 / 40 100 90 20 10
Hondo Muni Airport 66 77 56 82 59 / 50 100 40 0 0
San Marcos Muni Airport 65 75 58 78 59 / 50 90 90 10 0
La Grange - Fayette Regional 67 78 61 78 60 / 30 60 90 20 10
San Antonio Intl Airport 67 75 59 80 60 / 60 100 90 10 0
Stinson Muni Airport 67 77 59 81 60 / 50 90 90 - 0
Flash Flood Watch from 7 AM CDT Wednesday through Wednesday evening
Area Forecast Discussion
National Weather Service Houston/Galveston TX
940 PM CDT Tue Apr 23 2019
.NEAR TERM [Through Tonight]...
Surface analysis this evening has surface front from west central
Texas NE towards the Ozarks across Oklahoma. A few severe storms
were located along the boundary moving out of the Big Country
headed towards the DFW Metroplex. Outflow should re-enforce the
front and allow it to push farther south tonight into Wednesday
AM. Upper level trough over northern Mexico should push east
tomorrow across Texas. This should support a couple different
rounds of storms with heavy rainfall possible over the Brazos
Valley during the late afternoon/evening and then down along the
coast overnight. Squall line should move across the area overnight
but capping may limit the overall severe threat. SPC has a slight
risk over much of the area. Suspect the first round of storms towards
the Brazos Valley will have the higher severe potential given
weaker capping. Models hinting at a second increase in intensity
of storms overnight as the squall line pushes east of Houston
after midnight. There are still some timing differences in the WRF
runs as well as HRRR runs. The real question mark will be how much
the cap holds over SE Texas and if discrete cells can form which
will become severe. Otherwise there could be a mix of convective
modes and transition into more of heavy rainfall threat. Really
the mesoscale yet again will be giving us fits on how the severe
weather threat evolves tomorrow. Just now a really early look at
the 00Z WRF-ARW and the 00Z HRR extended range - both models hit
areas from near Brenham to Caldwell east to Huntsville/Crockett
with high QPF. This swath is quite a bit farther south and east
from where all the synoptic models place higher amounts of QPF. We
will have to watch to see if any of the other models from the 00Z
run show similar trends.
.PREV DISCUSSION /Issued 639 PM CDT Tue Apr 23 2019/...
Some light rain have been falling around Southeast Texas today associated
with weak disturbances moving across the area in the southwest flow
aloft. Anticipating a break in this activity tonight for a majority
of the area followed by a slight increase in rain chances during the
day tomorrow. Much better shower and thunderstorm chances are still
on track beginning early tomorrow evening across our western counties
and then spreading eastward during the remaining evening and overnight
hours across the remainder of the area as the upper low and associated
cold front move slowly eastward across the state. Dynamics are still
looking pretty good for possible strong/severe storms with this system.
The primary severe weather threat still looks like hail, strong winds
and lightning. Isolated tornadoes and locally heavy rainfall might
be possible too. While a majority of activity should be east of our
area by sunrise Thursday morning, the slow movement of the system might
allow for some daytime heating related redevelopment during the day
on Thursday. Everything should be off to our east Thursday evening
with high pressure beginning to build into the state. Looking at a
couple of coolish nights (Thursday night and Friday night) before
the high moves off to our east and onshore winds come back to the
area. While the end of the week and the weekend stay dry, lots of
sunshine will help to boost afternoon high temperatures into the mid
to possibly upper 80s. This forecast package has Monday dry followed
by low rain chances back to the area beginning Tuesday. 42
.AVIATION [00Z TAF Issuance]...
Big changes on the way, and this forecast mainly aims to sketch
out the highlights. VFR currently across the majority of the area,
but a couple are already leading the charge into MVFR that will
occur tonight. Some may even briefly dip into high IFR around
sunrise. Tomorrow, look for showers and eventually storms to push
in from the northwest late this afternoon into the evening. Have
begun to try to broadbrush that from IAH northward, and think that
will be able to hold off until the 06Z cycle coastward of IAH.
A fairly tight pressure gradient across the northern Gulf generated
from a Mobile Bay High and lowering northwestern Texas pressures has
maintained a moderate onshore wind. As the next storm system
develops out west, the onshore pressure will remain tight enough to
keep these regional Caution level winds in place through late
tomorrow night. Other than some scattered showers and a rogue
thunderstorm, local bay and Gulf weather will remain fairly benign
through tomorrow night. As we approach the late Wednesday evening
hours, the probabilities for rain and thunderstorms significantly
increase going into the (overnight) early Thursday morning hours.
Offshore winds behind a Thursday frontal passage will not be overly
strong, briefly Caution level, at most. Sea state will remain
elevated due to slightly higher period between Thursday morning`s
storms and post-frontal winds through Friday morning. High pressure
settles in over the weekend and settles both winds and sea state out
to tranquil. Weak onshore winds will return by Saturday afternoon.
.PRELIMINARY POINT TEMPS/POPS...
College Station (CLL) 66 78 61 76 60 / 20 70 90 20 0
Houston (IAH) 67 79 65 79 61 / 20 30 90 30 0
Galveston (GLS) 70 75 68 77 67 / 10 20 90 50 0
GM...SMALL CRAFT SHOULD EXERCISE CAUTION until midnight CDT tonight
for the following zones: Waters from Freeport to Matagorda
Ship Channel TX from 20 to 60 NM...Waters from High Island
to Freeport TX from 20 to 60 NM.
AREA FORECAST DISCUSSION...UPDATED
National Weather Service Jackson KY
1107 PM EDT Tue Apr 23 2019
Issued at 1106 PM EDT TUE APR 23 2019
Hourly pops have been updated based on recent radar trends and
trends in the convective allowing models. The threat for strong
storms has ended, though a rumble or two of thunder will remain
possible over the next few hours.
UPDATE Issued at 821 PM EDT TUE APR 23 2019
Some minor adjustments have been made to pops based on recent
radar trends and convective allowing models. The consensus of all
this is that locations from around I 64 and north should experience
numerous showers and some thunderstorms over the next few hours,
but the activity should remain north of the Mountain Parkway for
the most part. The potential for strong storms should diminish
over the next hour or two as sunset passes.
.SHORT TERM...(This evening through Wednesday night)
Issued at 425 PM EDT TUE APR 23 2019
19z sfc analysis shows a well defined cold front just northwest of
the Ohio River. This nearby presence has helped to support breezy
southwest winds of 10 to 15 mph across the area with gusts up to
25 mph. The more convective and mid level cloudiness associated
with the front has only just now started to shift into the
northern parts of the CWA. No showers or storms have developed
along this boundary near our area so far this afternoon. However,
initiation is expected momentarily as peak heating is taking its
toll with CAPE starting to exceed 1000 J/kg along and ahead of
the front. The sunshine and south winds supported temperatures
climbing into the upper 70s to lower 80s through eastern Kentucky
while dewpoints slipped into the middle to upper 40s, for most
The models are mainly in good agreement aloft through the short
term portion of the forecast depicting the split flow regime
across the region. The northern one takes a compact trough
through the eastern Great Lakes tonight with an impulse from the
southern stream sliding over northern Kentucky north of a rather
flat southeast ridge. This ridge builds a tad on Wednesday with an
uptick in heights for eastern Kentucky as the main southern
trough works further east in southern Texas. Additional energy
will dampen out over the area Wednesday night while we await the
southern stream trough`s arrival later in the week. The GFS,
ECMWF, and CMC are faster bringing this low east than the laggard
and stronger NAM - though this difference does not seem to
manifest itself downstream, at least through Thursday morning.
Given the limited model spread for the bulk of the time have
favored a blend as a starting point with a lean toward the HRRR
and NAM12 for details.
Sensible weather will feature the convection and storms yet to
develop along the front sliding into our northern counties this
evening. A few of these could become strong with gusty winds, CG
lightning, and heavy rain the main threat. The boundary will then
settle over the area tonight as the instability wanes and
convection tamps down. With the slight build in heights aloft on
Wednesday expect the boundary to be slow to initiate any renewed
convection of note - though by mid afternoon we should see that
development with thunder a possibility, but not as likely as this
evening given more limited instability and weaker mid levels. The
risk of convection continues into the night with the northern
fetches more favored than the south - and a better chance for
heavier rains through the entirety of the short term.
Used the CONSShort and ShortBlend as the starting point for all
the grids through the period with little adjustments to
temperatures aside from some near term extra cooling in the
valleys with sunset - outside of the convection areas in the
north. As for PoPs, have leaned on the high res CAMs to adjust
them this evening with the NAM12 the guide later on - in this
manner the diurnal trends where enhanced and more dominant than
implied by the blends.
.LONG TERM...(Thursday through Tuesday)
Issued at 300 PM EDT TUE APR 23 2019
The latest model suggests that we will see three weather systems of
note in the extended period. The latest data has a slow moving area
of low pressure moving across the Tennessee Valley region from
Thursday through the start of the upcoming weekend. A second weaker
area of low pressure is also forecast to move across the Great Lakes
region during the same time frame. A cold front trailing from the
northern system is then forecast to interact with the northern
fringe of the southern stream system. The combined moisture and
energy from both systems is then forecast to bring widespread rain
showers and a few thunderstorms to the area Thursday and Friday. The
data then suggests that we will see a brief lull in the from late
Friday through late Saturday, as a weak area of high pressure
settles over the area. After that, a third weak and faster moving
weather system is then forecast to move through the area from late
Saturday through late in the day on Sunday. The weekend system will
likely only produce general rain showers as it moves through. At the
very end of the period the models are trying to push yet another
area of low pressure across our area Monday night. Since this system
is being forecast so far out in the period, we will take it with a
grain of salt until the models come into better agreement.
Temperatures in the extended will be all over the place, with some
days seeing above normal highs and lows and other periods with below
normal readings. The warmest highs are expected on Monday and
Tuesday, with max readings in the upper 70s and lower 80s on tap on
those two days. The coolest day should be Sunday, when highs are
forecast to range from the mid 60s in the north to the lower 70s in
the south. The rest of the extended period should see normal highs.
Nightly lows are forecast to be in the 40s and 50s.
.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
ISSUED AT 815 PM EDT TUE APR 23 2019
Some convection is occurring across the OH Valley region in
advance of a slow moving cold front. This activity could affect
locations as far south as JKL and SJS, but SYM will have the
highest chance for a thunderstorm. With this, we have continued
with a few hours of VCTs for SYM only. As the boundary sags into
the area, ceilings should lower into the MVFR range across the
northern half to two thirds of the area between 6Z and 12Z before
improving back into the VFR range in most locations through
around 18Z. Winds should generally be 10KT or less through the
period and become more or less light and variable as the front
stalls out over the area.
Area Forecast Discussion
National Weather Service Marquette MI
628 PM EDT Tue Apr 23 2019
.SHORT TERM...(This evening through Wednesday)
Issued at 411 PM EDT TUE APR 23 2019
Water vapor imagery and RAP analysis show a trof moving e from the
Great Lakes region in an otherwise zonally oriented flow across the
northern CONUS/southern Canada. Within this flow, shortwave moving
across southern British Columbia will be the next feature of
interest during the short term. In the wake of the Great Lakes trof,
much drier air flowing into the Upper Great Lakes has resulted in
clouds clearing out from w to e today. However, some
stratus/stratocu still lingers over the eastern fcst area. Under
sunny skies, temps have risen into the 50s (near 60F in a few spots)
s central and interior w. Northerly wind off Lake Superior is
keeping conditions cool, upper 30s/lwr 40s, near the lake. It`s
especially chilly in n central and eastern Upper MI due to a
blustery n wind in those areas.
A quiet night is expected tonight as sfc high pres ridge, currently
extending from Hudson Bay across western Lake Superior to the
central Plains, drifts e across the area. Mainly clear skies
initially tonight will give way to some high clouds spreading across
the area as upstream waa regime spreads downsteam. Precipitable
water will be increasing from the w during the night, and along with
some high cloudiness, it won`t be an ideal radiational cooling
night. Still, with light/calm wind under passing sfc high pres
ridge, leaned fcst to the low side of guidance tonight. Temps should
fall to the mid 20s in the traditional cold spots in the interior
central and e. Earlier arrival of high clouds/higher precipitable
water and development of light se/s return flow will keep the far w
warmest, upper 30s/around 40F in the downslope areas near Lake
Low-level jet of 30-40kt in response to the approaching shortwave
will shift e over western Upper MI during the day on Wed. Since
theta-e advection is weak, have doubts on whether any -shra will
occur, especially in light of the dry air that lingers in the low
levels blo 5kft. For now, have only included schc pops over the nw
fcst area. Otherwise, will be a breezy, warmer day. Temps this aftn
out across the Dakotas are pushing thru the 60s with some lwr 70s
showing up as of 20z. Mid/upper 60s should be common for high tmeps
across the w half of Upper MI on Wed. Might see a few spots reach
70F. Will be cooler over the e with southerly wind up Lake MI. Temps
will range down to the 40s lakeside.
.LONG TERM...(Wednesday night through Tuesday)
Issued at 409 PM EDT TUE APR 23 2019
Continued southerly/southwesterly flow ahead of a shortwave trough
combined with cloudy conditions Wednesday night will keep
temperatures in the low to mid 40s. Some light showers will move
across from west to east, exiting before midday Thursday. As
conditions dry out and clouds clear, another nice spring day will be
in store with highs in the upper 50s east to mid 60s interior west.
A few spots that still have snow on the ground in the Keweenaw and
Michigamme Highlands will continue to melt off and runoff into
rivers will continue.
Another trough will dig in from the north on Thursday night into
Friday that will bring additional cloud cover, but the air mass
looks to be too dry to produce more than a few spotty showers,
mainly over the east. It will usher in a cooler airmass for the
weekend, with highs Saturday and Sunday topping out in the 40s.
A stronger system with a notable surface low is expected to pass to
our south Saturday evening and night. There is some discrepancy in
the strength and track of this system, but it is possible that areas
near the WI border will experience additional shower activity, and
perhaps even a few snow showers overnight. Following that, the
models continue to diverge. The EC would bring about a quarter inch
of QPF on Monday ahead of a trough that is not resolved in the
CMC/GFS or indicated in any of the ensembles, so for now POPs remain
low. A better signal for rainfall comes at the end of the forecast
period on Tuesday night, but there is plenty of time to work out the
details there. Ideally, area rivers will have some time to recede
before we get any more heavy precip events.
.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 628 PM EDT TUE APR 23 2019
VFR conditions will prevail at all sites thru this fcst period.
.MARINE...(For the 4 PM Lake Superior forecast issuance)
Issued at 411 PM EDT TUE APR 23 2019
Sfc high pres ridge currently extending ne to sw across western Lake
Superior will drift e tonight. As it does so, winds will remain
light, under 15kt, over the western part of the lake. Over the
eastern part of the lake, nnw winds around 20kt will fall off to
under 10kt tonight. Ahead of an approaching cold front, expect s to
se winds generally in the 10-20kt range on Wed, strongest over the e
half. Winds may increase a bit more over the e half Wed night prior
to passage of the cold front. Behind the front, westerly winds
should be mostly under 20kt on Thu. In the wake of another passing
cold front, w to nw winds up to 15-25kt are expected on Fri,
potentially up to 30kt over the e half. Winds should mostly be under
20kt over the weekend.
Area Forecast Discussion
National Weather Service Reno NV
323 PM PDT Tue Apr 23 2019
Warm days, cool to chilly nights, and dry conditions are expected this
week for northeast California and western Nevada. Warmer temperatures
will lead to increases in cold and swift flows for area streams, with
minor flooding possible for agricultural areas in the Carson Valley.
Isolated showers and thunderstorms are possible Wednesday and Thursday
afternoon and evening.
The main change to the forecast through Friday was to add
isolated showers and thunderstorms to eastern California and far
western Nevada Wednesday afternoon and evening.
Above to well above average temperatures will prevail for northeast
California, the Sierra, and western Nevada this week under an upper
ridge. Stronger east to northeast winds over high Sierra ridges last
night into this morning have diminished considerably this afternoon
as the upper ridge builds overhead.
Precipitation chances still don`t look great for Wednesday/Thursday,
but cannot rule out isolated afternoon/evening thunderstorms. Wednesday
may have the best shot with well above average temperatures and light
convergence (weak zephyr) over and just east of the Sierra by late
afternoon to foster deeper moist convection. The NAM has been consistent
showing this although it is a bit at odds with the high-res HRRR which
shows convection kicking well off the Sierra crest (into western NV).
Thursday, stronger westerly flow is expected with less convergence
outside of the Lassen Convergence Zone (north of Susanville) and
eastern Mono County and Mineral County.
Friday, chances for showers wane further as slight cooling (more stable)
and much weaker convergence under northwest flow inhibits deep convection.
We have left a slight chance of showers downwind of Lassen Peak with
leftover shallow moisture possibly bringing a brief shower or two.
.LONG TERM...Saturday into the beginning of May...
The pattern for this weekend into the beginning of next week looks
rather stagnant with the jet stream draped over the northern half
of the country allowing broad, weak areas of low pressure to drop
southward. Saturday looks to be the nicer day of the weekend as a
shortwave ridge develops over the U.S. Southwest leading to warm,
above average temperatures, a partly cloudy sky, and light
These conditions will not last long as a cut-off low pressure system
makes its way towards the southern California coast by Sunday afternoon.
As the system moves closer inland, it will begin to interact with a
more broader area of low pressure over the Pacific NW. According to
the recent long range deterministic model runs, cloud cover looks
to increase over the Sierra and western Nevada region with a cool
down in temperatures likely. Westerly winds should also pick up by
Sunday afternoon across the region with the chance of some rain showers
developing over areas mainly south of I-80.
Once we begin the new work week, these active weather conditions look
likely to remain with us as the cut-off low passing to our southeast
becomes absorbed by the broader area of low pressure to our north.
No major impacts are expected with a persistent west-northwest wind,
isolated rain showers, and average high/low temperatures for this
time of year.
As we begin the month of May, the GEFS & EPS show weak troughing over
the West Coast with no significant warm up anticipated for the next
week or two. Sounds like typical spring weather to me! -LaGuardia
VFR conditions and overall light winds will continue through Wednesday
as high pressure builds over the Sierra and western NV. There is a very
low (~5-10%) chance for a shower or thunderstorm for terminals across
eastern California and far western Nevada after 2-3 PM (21-22Z) Wednesday.
Any thunderstorms could bring outflow winds to 30 kts, a couple lightning
strikes, and brief -RA. Expect breezier conditions Thursday and Friday,
with a few showers or even an isolated thunderstorm for Thursday north
of KSVE and in Mineral County/near KHTH. -Snyder
Warmer daytime and overnight temperatures combined with lots of
sunshine and long days will lead to the first large pulse of melt
for the low to mid elevation snowpack. Flows are expected to be high,
cold and fast in snow-fed rivers and streams throughout the area.
Most rivers and streams are expected to stay significantly below
flood stages; however, the West Fork of the Carson River through
Carson Valley is forecast to be very near flood stage Thursday night
into Friday morning and again Friday night into Saturday morning.
With this in mind, we have issued a flood watch for the West Fork
of the Carson River for this period. Any increase in observed or
forecast temperatures will likely result in minor flooding in this
High flows are expected to continue into the weekend. Still, the
highest flows are still beyond the forecast window for most rivers
and streams draining high elevation terrain, especially from the Lake
Tahoe area south through Mono County. Remember: snowmelt peaks
typically occur in the evening and overnight hours in the higher
portions of the basin while peaks are more likely in the early
morning hours in the lower portions of the basin. -Bardsley
NV...Flood Watch from Thursday evening through Saturday morning
for portions of the Carson Valley.
For more information from the National Weather Service visit...
Area Forecast Discussion
National Weather Service Shreveport LA
1010 PM CDT Tue Apr 23 2019
An organized area of convection over N TX has shown signs of
slowly building E this evening, in an area of mid-level forcing
ahead of a deepening closed low sinking slowly S across NW old MX.
This is occurring near and just SE of a slow moving sfc front
extending from near a COM, to MWL, to N of a GYI, to AQR and MLC
line as of 03Z. The short term progs are in good agreement with
this bndry moving very little overnight, and may actually be
convectively reinforced SE a bit more, with a SSE low level flow
maintaining low level convergence and hence the convection
overnight near this bndry, as broad diffluence aloft persists
ahead of the deepening closed low to the SW. The ongoing
convection looks to eventually build NE into portions of extreme
NE TX/SE OK/possibly into adjacent sections of SW AR mainly after
midnight tonight, as large scale forcing expands NE ahead of the
front and NE ejecting shortwave energy. Fortunately, MLCapes
continue to diminish further NE away from the current convection
into NE TX/SE OK, thus the convection should continue to gradually
weaken as it expands ENE into these areas later tonight.
Given the good agreement with the latest HRRR and 00Z NAM/18Z GFS,
have raised pops to likely across the far NW zones, tapering pops
to chance to near/N of the I-20 corridor of E TX into much of SW
AR. Also made a few minor adjustments to the forecast min temps,
bumping temps up a degree or so across E TX/SW AR/NW LA where S
winds and the thickening convective debris should limit the temp
fall. Convection coverage should increase throughout the morning
Wednesday over E TX once better large scale forcing increases
ahead of the upper low as it emerges out over WCntrl TX.
Zone update already out...grids will be available shortly.
.PREV DISCUSSION... /issued 732 PM CDT Tue Apr 23 2019/
For the 24/00Z TAF period, VFR conditions are prevailing to begin
this period as cu field has scattered out this afternoon. Light
southerly flow will continue and aid in the redevelopment of lower
cigs after midnight through Wednesday, mainly in the MVFR range
with some intermittent IFR cigs possible around daybreak. Cigs
will be slow to lift through the morning with increasing chances
for convection through the afternoon hours ahead of an upper level
trough pivoting across Texas. For now, have only included VCTS in
this TAF cycle during Thursday afternoon across our east Texas
terminals as well as SHV/TXK. Otherwise, look for MVFR/low VFR
cigs to prevail during the latter half of the period ending at
.PRELIMINARY POINT TEMPS/POPS...
SHV 63 76 62 75 / 10 50 90 60
MLU 61 78 64 75 / 5 20 50 70
DEQ 64 73 59 72 / 60 60 90 70
TXK 62 73 60 73 / 40 70 90 60
ELD 61 77 63 73 / 10 20 70 60
TYR 64 72 60 74 / 30 80 90 50
GGG 63 74 60 75 / 20 70 90 50
LFK 64 78 62 77 / 10 60 90 50