Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 05/22/20
Area Forecast Discussion
National Weather Service Albuquerque NM
300 PM MDT Thu May 21 2020
.SYNOPSIS...
Isolated thunderstorms are possible this evening over northeast New
Mexico along a weak frontal boundary. The front will retreat Friday,
with critical fire weather conditions developing over northeast New
Mexico. Critical conditions will be more widespread over eastern New
Mexico Saturday. A change in the weather pattern will occur early
next week as cooler and moist air invades the east and an upper low
develops over the state. Chances for showers and storms will be most
widespread from the central mountain chain over the plains Sunday
through Memorial Day. The upper low will wobble slowly to the east
thereafter, so shower and storm chances may trend downward by mid
week while temperatures warm.
&&
.DISCUSSION...
.SHORT TERM (TONIGHT THROUGH FRIDAY NIGHT)... As one low migrates
north to the Canadian border, a second low will be dropping down
from the Pacific NW over the next several days. Meanwhile, a
relatively dry shortwave trough will trek across the state, leading
to breezy to locally windy conditions along and east of the central
mountain chain. With the region of higher dewpoints shifting further
east, the HRRR has become less enthused with the idea of convection
across Union County this afternoon. The HREF on the other hand shows
precipitation increasing ahead of a surface low through 09z. A stray
thunderstorm or two cannot be ruled out, given the negative LI`s and
marginal CAPE (200-400 J/kg). Overnight, the northern mountains can
expect temperatures near or below freezing, but decided to hold off
on another Freeze Warning for this evening.
On Friday, a leeside trough will increase southwesterly winds east
of the central mountain chain. Daytime highs will continue to follow
the warming trend, with much of the state near or above normal.
LONG TERM...(SATURDAY THROUGH WEDNESDAY)... Saturday will be breezy
to windy and very dry as upper trough/low moves into the Great Basin
and central Rockies. Highs Saturday will range from near average
west and central to about 10 degrees warmer than normal over the
east. Some energy will develop southward into the trough Sunday,
allowing a second upper low to be generated over northern NM. At the
same time, a cold front will surge into the northeast then to the
east slopes of the central mountain chain Sunday night/Monday. There
are timing differences between the models in regards to the front
and exactly where the upper low center will be. However, the main
message is that there will be a cool down by Sunday night and
Memorial Day with highs on Memorial Day about 5 to 15 degrees below
average, and chances for showers and storms, especially from the
central mountain chain over the plains. Chances for rain taper off
Tuesday and Wednesday as temperatures slowly warm back to above
normal. The upper low could hang around through next week, with NM
in the backwash, so the warming and drying trend for the east in the
grids may be a bit ambitious if the operational GFS turns out to be
accurate.
&&
.FIRE WEATHER...
Breezy to locally windy conditions this afternoon and evening will
lead to a brief period of critical fire weather conditions from
Clines Corners to Conchas, as a shortwave trough crosses New Mexico.
On Friday, the warming trend will continue, with temperatures up to
10 degrees above normal across the eastern plains. Minimum relative
humidities will be less than 10% across much of the state. Strong
south to southwesterly winds will develop in the afternoon hours
Friday east of the central mountain chain, due to a leeside trough.
Thus, the Fire Weather Watch across the northeast highlands was
upgraded to a Red Flag Warning, as these conditions continue for
several hours in the afternoon.
Widespread critical fire weather conditions are also forecast for
much of the eastern plains on Saturday. Winds will increase as the
leeside trough deepens. Combined with high Haines values and
temperatures 5-10 degrees above normal across the east, this was the
basis for the Fire Weather Watch in effect for Saturday. Ventilation
rates will start off poor to fair on Friday, becoming excellent by
Saturday.
As a low dives down toward New Mexico combined with a backdoor cold
front Sunday and Monday, there is a chance for wetting precipitation
across much of the eastern plains Monday and cooler temperatures
forecast, which should help mitigate some of the fire weather
concerns across the eastern portion of the state.
&&
.AVIATION...
18Z TAF CYCLE
VFR conditions to prevail through the TAF period. Breezy conditions
will develop this afternoon (up to 25 kts), as a dry shortwave treks
eastward across the state today. Low-level moisture should stay well
east of the NM/TX border, but a stray thunderstorm or two is
possible across the far northeastern corner of the state. The HREF
keeps convection going after 09z, but the HRRR is less enthused
about any precipitation. Some brief MVFR ceilings may be possible,
but it shouldn`t impact any TAF sites.
31
&&
.PRELIMINARY POINT TEMPS/POPS...
Farmington...................... 38 81 47 79 / 0 0 0 0
Dulce........................... 30 77 35 75 / 0 0 0 0
Cuba............................ 38 76 43 76 / 0 0 0 0
Gallup.......................... 28 78 36 76 / 0 0 0 0
El Morro........................ 32 75 36 73 / 0 0 0 0
Grants.......................... 30 79 37 78 / 0 0 0 0
Quemado......................... 35 77 39 76 / 0 0 0 0
Magdalena....................... 43 80 47 80 / 0 0 0 0
Datil........................... 38 76 42 75 / 0 0 0 0
Reserve......................... 35 77 38 79 / 0 0 0 0
Glenwood........................ 44 80 49 82 / 0 0 0 0
Chama........................... 29 70 33 70 / 0 0 0 0
Los Alamos...................... 48 75 50 76 / 0 0 0 0
Pecos........................... 41 75 46 76 / 0 0 0 0
Cerro/Questa.................... 33 75 39 75 / 0 0 0 0
Red River....................... 29 65 36 64 / 0 0 0 0
Angel Fire...................... 21 69 29 68 / 0 0 0 0
Taos............................ 30 78 35 76 / 0 0 0 0
Mora............................ 37 75 41 75 / 0 0 0 0
Espanola........................ 42 81 47 82 / 0 0 0 0
Santa Fe........................ 43 77 45 76 / 0 0 0 0
Santa Fe Airport................ 40 80 43 79 / 0 0 0 0
Albuquerque Foothills........... 50 81 53 82 / 0 0 0 0
Albuquerque Heights............. 49 82 52 83 / 0 0 0 0
Albuquerque Valley.............. 47 84 51 85 / 0 0 0 0
Albuquerque West Mesa........... 48 82 52 84 / 0 0 0 0
Belen........................... 44 85 48 86 / 0 0 0 0
Bernalillo...................... 45 83 50 85 / 0 0 0 0
Bosque Farms.................... 45 84 48 85 / 0 0 0 0
Corrales........................ 47 83 50 85 / 0 0 0 0
Los Lunas....................... 45 85 48 85 / 0 0 0 0
Placitas........................ 46 81 51 80 / 0 0 0 0
Rio Rancho...................... 47 82 51 84 / 0 0 0 0
Socorro......................... 48 86 51 88 / 0 0 0 0
Sandia Park/Cedar Crest......... 44 77 46 77 / 0 0 0 0
Tijeras......................... 42 79 47 79 / 0 0 0 0
Edgewood........................ 36 79 44 79 / 0 0 0 0
Moriarty/Estancia............... 33 80 42 81 / 0 0 0 0
Clines Corners.................. 40 77 44 77 / 0 0 0 0
Mountainair..................... 40 79 45 79 / 0 0 0 0
Gran Quivira.................... 42 79 47 79 / 0 0 0 0
Carrizozo....................... 50 81 53 82 / 0 0 0 0
Ruidoso......................... 46 76 50 76 / 0 0 0 0
Capulin......................... 41 77 45 79 / 20 5 0 0
Raton........................... 40 82 43 83 / 10 0 0 0
Springer........................ 41 83 44 83 / 5 0 0 0
Las Vegas....................... 40 78 44 78 / 0 0 0 0
Clayton......................... 52 82 51 87 / 20 0 0 0
Roy............................. 47 80 47 83 / 0 0 0 0
Conchas......................... 51 88 53 91 / 0 0 0 0
Santa Rosa...................... 48 87 54 89 / 0 0 0 0
Tucumcari....................... 55 91 56 94 / 0 0 0 0
Clovis.......................... 51 87 54 91 / 0 0 0 5
Portales........................ 52 89 55 93 / 0 0 0 0
Fort Sumner..................... 51 88 53 92 / 0 0 0 0
Roswell......................... 53 93 55 96 / 0 0 0 0
Picacho......................... 52 87 54 89 / 0 0 0 0
Elk............................. 49 83 52 84 / 0 0 0 0
&&
.ABQ WATCHES/WARNINGS/ADVISORIES...
Fire Weather Watch from Saturday morning through Saturday evening
for the following zones... NMZ103-104-108.
Red Flag Warning from 1 PM to 7 PM MDT Friday for the following
zones... NMZ103.
&&
$$
Area Forecast Discussion
National Weather Service Denver/Boulder CO
901 PM MDT Thu May 21 2020
.UPDATE...
Issued at 901 PM MDT Thu May 21 2020
Have updated the forecast to remove evening showers over the
Palmer Divide and added an area of showers through midnight over
the far northeast plains. Late afternoon cloudiness over the
mountains and foothills has been dissipating except near the
Wyoming border where a few showers with more vertical development
had formed. This trend will continue, however the HRRR shows the
convection over the southeast corner of Wyoming sticking together
for a few hours and moving over Logan and northern Washington
Counties. Have thrown in isolated thunderstorms up til midnight
over these areas. Otherwise the forecast is unchanged.
Will need to keep an eye out for any areas of stratus developing
over the eastern plains, as thunderstorms over western Kansas are
expected to produce a lot of rain and rain-cooled air which could
move back across eastern Colorado overnight. At the present time,
there is quite a cirrus shield over northeast Colorado, produced
by the southwestern Kansas convective complex. That will make it
difficult to monitor the progress of any stratus clouds, at least
over the next few hours.
&&
.SHORT TERM...(This evening through Friday)
Issued at 239 PM MDT Thu May 21 2020
Temperatures have been around seasonal normals today after being
at or near record highs the past two days. Conditions have been
pretty stable but a few clouds are beginning to develop over the
southern Front Range foothills. These clouds will continue to grow
through the late afternoon and evening and will produce high
based showers that spread over the urban corridor. Not much rain,
if any, is expected to reach the surface but these showers could
produce wind gusts up to 35 mph.
Tonight, a few showers and storms may develop on the south side
of the Palmer Divide and may work their way over to Lincoln
County around midnight. Otherwise, lows will be around seasonal
normals with light winds and dry conditions. A few low clouds may
spread across the far eastern plains as moisture works its way
back into the state.
Mid to upper level ridging will be over our forecast area on Friday.
The subsident flow will keep skies clear for much of the day
allowing for temperatures to warm 5 to 10 degrees above normal.
High based showers will again be possible over the foothills and
urban corridor with more wind than rain. Otherwise, relative
humidities will drop to the low teens across the majority of our
CWA except for the higher terrain in the mountains. With winds
expected to be on the lighter side, a Red Flag Warning won`t be
needed.
.LONG TERM...(Friday night through Thursday)
Issued at 239 PM MDT Thu May 21 2020
Models have weak to moderate southwesterly flow aloft for the CWA
Friday night through Sunday. Models have an upper trough move
into Colorado on Sunday, then move slowly eastward across the
state through Monday night. The QG Omega fields have upward
vertical velocity progged for the CWA Friday night through Sunday
night. The low level winds look to be normal drainage patterns
Friday night. It looks like southerly winds prevail on Saturday,
then a surge of upslope moves in Saturday evening. North
northeasterly winds prevail most of Saturday night. Northerly
upslope winds are progged much of Sunday, Sunday night on into
Monday. For moisture, there is some around Friday night through
Saturday night, but there is an increase in moisture for Sunday
and Sunday night. There is limited CAPE progged over the plains
Friday evening. CAPE values are pretty decent Saturday late day,
mainly over the eastern half of the plains. On Sunday, there is
CAPE over the mountains and foothills; not much on the plains with
the more stable, cooler airmass in place. Cross sections show a
pretty strong cap just above 700 mb. Will leave some 10% pops over
the far northeast corner Friday evening. Late day Saturday`s pops
will be 20-40%s in the mountains and foothills, with 10-20%s over
the plains. Sunday is the best shot at some needed rain. Will go
with 30-60% pops across all the CWA Sunday well into Sunday
night. For temperatures, Saturday`s highs are 0-2 C cooler than
Friday`s. Sunday`s readings cool of some 6-12 C from Saturday`s.
For the later days, Monday through Thursday, models show a weak
upper trough/closed low over the CWA and southern Colorado. Monday
should stay cool with some moisture around. From Tuesday through
Thursday, models keep an upper closed low over the panhandle of
Texas, with weak flow aloft over the CWA. It looks pretty dry with
an increase in moisture on Thursday. Temperatures are below
season normals on Monday, near normals on Tuesday, then a tad
above normals Wednesday and Thursday.
&&
.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
Issued at 901 PM MDT Thu May 21 2020
No major aviation impacts over the next 12 to 24 hours, unless a
deck of low stratus forms over the eastern plains and moves back
into the Denver area. If the stratus forms, then MVFR/IFR cloud
decks could affect the morning arrival rates. Winds will be east
to southeasterly overnight.
&&
.FIRE WEATHER...
Issued at 239 PM MDT Thu May 21 2020
The minimum relative humidity progs are in the 10-15% range over
much of the southern third of the CWA Saturday afternoon and early
evening. Most areas don`t show high enough wind speeds to warrant
a Red Flag Warning, however, South Park and Lincoln County show
speeds getting close to criteria. It will need to monitored for
potential highlights. Sunday cools off considerably with decent
enough moisture around for wetting rains in nearly all of the
forecast area.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
UPDATE...Dankers
SHORT TERM.....Danielson
LONG TERM......RJK
AVIATION...Dankers
FIRE WEATHER...RJK
Area Forecast Discussion
National Weather Service Dodge City KS
555 PM CDT Thu May 21 2020
...updated aviation...
.SHORT TERM...(This evening through Friday)
Issued at 226 PM CDT Thu May 21 2020
MSAS showing weak surface low pressure centered over the western
Oklahoma panhandle with attendant cold front from wet of Syracuse
into southwest Nebraska this afternoon. Also a dryline and warmfront
extended south from near LBL into the Texas Panhandle. Ahead and
east of these features has been a stubborn field of stratus clouds
that has created a large temperatures difference from the upper 60s
to low 70s under the cloud cover and contrasted by low 80s over the
Sunny Syracuse-Johnson-Elkhart area. Latest HRRR initiate these
convective elements at 21 UTC along the cold front along the highway
25 corridor with organized elements reaching the highway 83 corridor
by around 10 pm. In addition to a hail and 60-70 mph wind threat, a
sizable area of 1 to 2 inch rain is likely with more localized areas
of 3 and 4 inches just as likely. Increased Pops over the area as
widespread trailing stratiform precipitation is likely beyond
midnight even as the overall severe risk should be decreasing.
Uncertainty with respect to and additional marginally elevated
severe pulse hail storms in the southeast will revolve around mid
level wave that will be moving into the area during the overnight
hours. Lows are forecast from the mid 50s west to more mild
summerlike 60s across south central Kansas.
.LONG TERM...(Friday night through Thursday)
Issued at 226 PM CDT Thu May 21 2020
Potential exists for thunderstorms to be ongoing early Friday
morning across the eastern and especially south central Kansas
counties as models show a mid level trough/weak pvu anomaly moving
though the area with still conditionally unstable air. This
should clear out though with sky becoming sunny area wide by
afternoon resulting in temperatures warming into the 80s all the
way to Hays. It will likely remain inactive later in the day
Friday with respect to convection, however the 850 wind field
transitions from weak easterly flow Friday to veering and
increasing winds though Saturday, with stronger south winds, and
better moisture transport ahead of a dryline for Saturday late
afternoon and Saturday evening. As a result , convection is
possible Saturday across the eastern counties. The southwest winds
will make temperatures much warmer on Saturday, before a cold
front tempers highs and focuses severe weather chances once again
along a southward propagating cold front through Sunday night.
This will setup Monday to likely be cooler and cloudy and perhaps
showery with diurnal thunderstorms.
&&
.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
Issued at 555 PM CDT Thu May 21 2020
The main concern for the TAF forecast is +TSRA for the terminals this
evening. All modes of severe threats will be possible with this activity...
landspouts, large hail, and severe outflow winds of 50+kt. Mid to late
evening is the most likely time of impacts to the terminals. This activity
will eventually evolve into a line and move out of the terminal space
by 06Z. Tranquil weather is expected thereafter. With continued moisture
advection, MVFR cigs may be possible once again by 12Z.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 56 81 59 91 / 60 20 0 0
GCK 53 81 56 91 / 80 10 0 0
EHA 54 84 56 91 / 40 10 0 0
LBL 54 83 58 93 / 50 20 0 0
HYS 57 80 56 88 / 80 20 10 10
P28 61 81 61 90 / 70 60 10 10
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...Russell
LONG TERM...Russell
AVIATION...Sugden
Area Forecast Discussion...CORRECTED
National Weather Service Quad Cities IA IL
1013 PM CDT Thu May 21 2020
...00Z AVIATION UPDATE...
.SYNOPSIS...
Issued at 302 PM CDT Thu May 21 2020
RAP analysis placed an upper low over NW Kentucky, slightly north
of where it was yesterday. This subtle retrogression has ensured
that we stay under the widespread low clouds today into tonight.
Temps so far this afternoon were well below normal ranging from
the upper 50s to lower 60s. We should warm several more degrees by
the late afternoon.
&&
.SHORT TERM...(This Evening through Friday)
ISSUED AT 302 PM CDT Thu May 21 2020
Light ESE winds are expected overnight as temps cool into the 50s.
There is a slight chance for patchy drizzle, but most locations
will probably stay dry. On Friday, the nearly stationary upper
low that brought 6+ days of low clouds to the Upper Mississippi
Valley will begin to track into the Eastern U.S. Subsidence
behind the low should lead to occasional breaks in the cloud
cover, allowing highs to reach the lower 70s. Uttech
.LONG TERM...(Friday Night through Thursday)
ISSUED AT 302 PM CDT Thu May 21 2020
Models are coming into better agreement with a stalled but active
pattern across the Plains for the next week. The main forecast
concerns were chances of precipitation through the period.
This weeks pesky upper level low will be shifting to the east
Friday night into Saturday as a 500 MB shortwave trough lifts from
southern Plains and into the Great Lakes by Saturday night. This
will mark the transition to a 500 MB pattern featuring a trough in
the west and a ridge in the east through early next week. This
will result in a southwesterly flow aloft from the Southwest into
the Great Lakes region. The pattern begins to break down on
Tuesday as a vort max dropping into the base of the western trough
and closes off resulting in another block forming in the
atmosphere across the southern US. This will result in a stalled
but active pattern through the end of next week. The main belt of
the westerlies will be just to our north through the period. This
will result in periods of showers and thunderstorms through the
week as pieces of energy pass to our north or eject towards the
area from the closed low. This could potentially leave a warm and
humid airmass across the Plains for much of the week.
Precipitable water values through the week are in the 1.50 to 1.75
inch range which is about 125 to 150% of normal so there could be
the potential for locally heavy rainfall. Temperatures are
forecast to be in the upper 70s to lower 80s which is near to
slightly above the normal temperatures which are in the mid to
upper 70s this time of year.
In the Friday night timeframe, a low level jet of 20 to 30 knots
will develop ahead of the lifting shortwave bringing showers and
thunderstorms to the area Friday night into Saturday. The better
lift will shift off to the east after 12 UTC on Saturday with
showers and thunderstorm chances coming to an end. Shortwave
ridging will build into the area Saturday afternoon into Sunday
bringing a dry period to the area. Temperatures will be noticeably
warmer with highs around 80 and dewpoints in the mid 60s.
&&
.AVIATION...(For the 00Z TAFS through 00Z Friday Evening)
ISSUED AT 611 PM CDT Thu May 21 2020
Persistent stratus will remain over the area overnight through
much of Friday with ceilings primarily in the MVFR range. The
exceptions will be early this evening, with some sites initially
VFR before ceilings begin to lower, and the other will be mid to
late afternoon Friday, when lifting ceilings may bring VFR
conditions. There is a potential for patchy drizzle late tonight,
but confidence is not high enough to include this in the
forecasts.
&&
.HYDROLOGY...
Issued at 1034 AM CDT Thu May 21 2020
The Rock River has crested at Joslin and Moline and are currently
falling. Both locations are expected to fall below flood stage
late Sunday night or Monday.
Slight rises are occurring on the Mississippi River north of the
Quad Cities due to heavy rains to our north this past weekend. All
of these rises will remain well below flood stage.
A more active pattern returns to the area Friday night through
next week with daily chances of showers and thunderstorms. This
pattern may support locally heavy rainfall which could delay the
rate of fall of flood waters on Rock River as well as new rises on
other area tributary rivers.
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
...Corrected Long Term Discussion..
SYNOPSIS...Uttech
SHORT TERM...Uttech
LONG TERM...Cousins
AVIATION...Sheets
HYDROLOGY...Cousins
AREA FORECAST DISCUSSION
National Weather Service Kansas City/Pleasant Hill MO
704 PM CDT Thu May 21 2020
.Discussion...
Issued at 349 PM CDT THU MAY 21 2020
The pattern we have been stuck in for almost a week now due to the
stalled cut-off low to the east will finally end overnight. The
first of many shortwave troughs we will see over the next week is
currently located over eastern Kansas. This wave has helped develop
elevated showers and isolated thunderstorms all day over that area.
Induced ridging over our area on the east side of the mid-upper
level cut-off low has stalled this feature most of the day, but is
starting to break down as the low slowly shifts east. This may allow
some elevated showers and a possible isolated thunderstorm to push
into our area in the next few hours up until sunset. The area did
get a small break in the lower clouds which is allowing our
southwest counties up into the KC Metro to quickly heat up into the
lower to mid 70s in the next couple hours before the mid clouds
arrive.
The next, more substantial, shortwave trough is currently
exiting the Rockies creating multiple surface lows to form along the
front range. CAM guidance is indicated a possible MCS pushing
through our area tomorrow after sunrise with the start of that
convection currently developing near the CO border now. Synoptically
that solution looks favorable with a LLJ forming up shortly after
sunset over OK and southern KS and strong WAA over eastern KS ahead
of the low building MUCAPE ahead of the possible MCS. How far north
storms will form over western KS will play a major factor in how
much of our area will be impacted tomorrow morning. Forward and
backward propagating Corfidi vectors indicate a E to NE motion for
any MCS that would develop over eastern to central KS. With plenty
of MUCAPE early on, a LLJ to help drive the motion, and favorable
effective and 0-3km shear vectors the possibility of strong to
severe storms just after sunrise over eastern KS is looking more
likely. The main limiting factor would for our area would be how
much MUCAPE would be available at arrival. The HRRR currently
indicates around 800-1000 J/kg so it could be weakening or have
become cold pool dominant as it arrives. Damaging winds would be the
main threat with an arrival time around 9AM for our western
counties. Due to the timing of this feature, our best severe weather
chances now look to be earlier in the day than in the afternoon as
we will have to recover from any cold pool draped over our area.
There is still a chance this occurs over our southern counties,
mainly south of HWY 50, in the afternoon. If we can get above 75F
and recover and get MLCAPE values greater than 1000 J/kg then the
second chance for severe is possible late afternoon on Friday. All
modes would be on the table if this were to occur with a nice backed
surface wind pattern and decent effective shear of 40kts. NAM4km and
HRRR to hint at this occurring, but more than likely under estimate
the cold pool effects on the backside of the MCS.
Summer actually arrives to the area Saturday as a trough deepens
over the western CONUS allowing strong WAA at all levels to push
into the Plains. Not only will we get the warmer temperatures (mid
80s) we will open up the Gulf of Mexico and likely see some
dewpoints in the upper 60s and lower 70s. This will make Saturday
feel much warmer than it has recently with heat indices near 90 and
something the public will not be acclimated too. Storms look to
develop over Nebraska Saturday afternoon which could transition to
an MCS Saturday night as a strong LLJ forms up over eastern KS.
Model guidance differs slightly on just how far south the initial
storms will form with NAM being further north, but if they can form
up along the KS/NE border then our northern counties may see a MCS
push through Sunday morning. High MUCAPE values (3000+ J/kg) would
be available for any MCS to feed on as it propagates east, so this
will be something worth watching as we get closer to Saturday night.
As the long wave trough pushes east a cold front/stationary boundary
will develop Sunday afternoon over central KS up through IA. This
boundary will slowly shift to the SE over time, but will be the
focal point for a more long duration rainfall event for the area.
PWAT values will be near climatological maximums of 1.75" with a
stalled SW-NE oriented boundary, multiple shortwave troughs, and
storm motion along the boundary. This all sets up for possible
flooding Sunday night into Tuesday morning as 2-3", possibly more
with convection, fall over the Missouri River valley. How much rain
we get Friday may contribute to the overall flash flooding potential
so we will need to watch this as we get closer to the end of the
weekend.
&&
.Aviation...(For the 00Z TAFS through 00Z Friday Evening)
Issued at 705 PM CDT THU MAY 21 2020
Expect low clouds to persist for the bulk of the forecast period,
perhaps in and out of MVFR territory, and even some brief periods
of IFR. Have opted for a more optimistic forecast for now, but
can continue to monitor. Overnight light showers will be possible
at the terminals, but thunder seems unlikely at this point, and
prevailing rain also seems unlikely until a line of probably
subsevere thunderstorms gets to the terminal around 14z-15z.
Expect that to be a pretty quick round of prevailing rain with
gusty winds and out of the terminals by around 18z.
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
MO...NONE.
&&
$$
Discussion...Barham
Aviation...Leighton
Area Forecast Discussion
National Weather Service Austin/San Antonio TX
916 PM CDT Thu May 21 2020
.UPDATE...
Quick forecast update mainly to adjust PoPs downward. It has been a
quiet night across South Central Texas with only a few showers and an
isolated thunderstorm forming across the Coastal Plains earlier this
evening. The HRRR has trended drier with recent runs, while other
mesoscale models do try to bring the thunderstorms ongoing to the
northwest of our area around San Angelo towards the Hill Country
later tonight. Think tonight should remain on the dry side, but have
left some slight chance PoPs in mainly across areas along and west of
I-35 to cover any of the storms to our west and northwest sneaking
into the area. Trended all of the other hourly weather grids to match
current observational trends.
&&
.PREV DISCUSSION... /ISSUED 651 PM CDT Thu May 21 2020/
AVIATION...
VFR conditions prevail across South Central Texas this evening. A few
showers have popped up along the Coastal Plains, but these quickly
dissipated. Convection across Mexico has remained well west of Del
Rio. A few showers are still possible around San Antonio for the next
few hours, before the lack of heating should dry everything out after
sunset. MVFR and then IFR cigs will be possible along the I-35
corridor overnight tonight in the moist environment in place. VFR
conditions will return between 14z-16z Friday morning. Isolated to
scattered convection will be possible Friday afternoon but placement
is uncertain so will not include mention in the TAFs at this time.
PREV DISCUSSION... /ISSUED 313 PM CDT Thu May 21 2020/
SHORT TERM (Tonight through Friday Night)...
An upper level trough covers the western half of the country with
southwesterly to westerly flow over Texas. Surface winds were from
the south keeping warm, moist air in place across our CWA. The
boundary layer is conditionally unstable this afternoon and
convection has already begun over the mountains in Mexico. Storms
may form along the dryline farther north in West Texas and may move
into our CWA later this evening. Although there is good instability
there is a lack of forcing, so whether storms form is still
questionable. If they do, they may produce large hail or damaging
wind gusts. SPC has included the northern and western part of our
CWA in the Marginal risk area for tonight. The upper trough will
move slowly toward the east Friday. The airmass over South Central
Texas will remain about the same and the forecast for Friday and
Friday night will be about the same. There won`t be any strong
forcing, but the atmosphere will be conditionally unstable. If
storms can form, they could be strong. We will continue to carry
slight to low end chance POPs.
LONG TERM (Saturday through Thursday)...
An active Memorial Day weekend through middle portions of next week
is shaping up as we enter a wetter pattern. The period begins with a
trough digging through the Rockies and Four Corners Saturday. Models
are indicating a mid level disturbance, in the southwest flow aloft
ahead of the larger trough, pivoting into the region during the day
on Saturday and into Saturday night. There seems to be a signal that
a complex of storms may form either to the west or northwest and
move into the area Saturday night into Sunday morning. It`s difficult
to say where exactly, and as we have seen lately mesoscale features,
such as remnant outflow boundaries and MCVs, can wreak havoc on a
forecast.
The upper level trough eventually digs south through the southern
Rockies Sunday and closes off over Northwest Texas Monday into
Tuesday. From there a blocking pattern sets up through potentially
the end of next week, with the low meandering over Northwest or North
Texas. This places South Central Texas in an active scenario for
additional rounds of showers and storms, with the potential for
pockets of locally heavy rainfall given the anomalously high
precipitable water values forecast. It is extremely difficult this
far out to pinpoint timing and locations of these rounds given some
of the mesoscale reasons already listed and subtle difference in the
placing of the larger scale features with the global models. Although
there does appear to be another signal Monday night into Tuesday,
where a slow moving cold front could focus heavy rainfall. We are
currently messaging the following:
1) Multiple rounds of showers and storms are possible over the
Memorial Day weekend through the middle portions of next week.
2) Stay "Weather Aware" and check the forecast often through the
Memorial Day weekend as details become clearer.
3) There will likely be a few rounds of strong to severe storms in
addition to pockets of heavy rainfall which could lead to flooding
4) Forecast confidence is low on the timing of these sounds of
storms.
&&
.PRELIMINARY POINT TEMPS/POPS...
Austin Camp Mabry 91 72 89 74 88 / 20 20 30 10 30
Austin Bergstrom Intl Airport 91 71 89 73 88 / 20 20 30 10 30
New Braunfels Muni Airport 91 71 89 73 88 / 30 30 30 10 30
Burnet Muni Airport 89 70 88 71 85 / 30 20 20 10 30
Del Rio Intl Airport 96 74 93 74 92 / 20 20 20 20 30
Georgetown Muni Airport 90 72 89 72 88 / 20 20 30 10 30
Hondo Muni Airport 92 73 90 73 91 / 30 20 20 20 30
San Marcos Muni Airport 91 72 89 72 88 / 30 20 30 10 30
La Grange - Fayette Regional 89 74 90 74 90 / 10 30 30 10 20
San Antonio Intl Airport 93 74 91 74 89 / 30 20 30 20 30
Stinson Muni Airport 92 73 92 75 90 / 30 20 30 20 30
&&
.EWX WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
Short-Term/Aviation...Treadway
Long-Term...BMW
Area Forecast Discussion
National Weather Service Grand Forks ND
1009 PM CDT Thu May 21 2020
.UPDATE...
Issued at 1009 PM CDT Thu May 21 2020
A few showers are still lingering over the far northern Red River
Valley, while additional showers are starting to develop over
north central SD. It still looks like isolated to possibly
scattered showers should redevelop into our area overnight before
transitioning mainly into west central MN. There is enough
lingering instability than an isolated thunderstorm can`t be ruled
out, and we have seen activity on GOES-East GLM at times this
evening. Amounts are still expected to be ling (0.1" or less where
showers track), so impacts will be minimal.
UPDATE Issued at 649 PM CDT Thu May 21 2020
Light returns on radar have mainly been associated with virga,
though there have been a few reports of light rain (likely
sprinkles). RAP analysis still shows 250-500 J/KG MUCAPE, so
it`s not impossible to think a stray thunderstorm could develop
along surface trough axis/stationary front before sunset, but so
far it looks like we are approaching a "lull" in activity and
mainly non-measurable precip (no impacts). Better coverage of
measurable may arrive later tonight as previous forecast
reflected (west central MN). Besides matching near term trends I
held off on a major overhaul to current short term forecast, and
will continue to monitor.
&&
.SHORT TERM...(This evening through Friday night)
Issued at 325 PM CDT Thu May 21 2020
Near term concerns will be confined to low rain chances and temps.
Will continue to see increasing moisture with southerly winds
into the evening as 925mb 30kts persists. Weak mid level
convergence area within the mean flow evident on area radars with
elevated returns may allow additional development of showers or
storms this evening across eastern ND. CAMs suggesting that
possibility though seeming more and more unlikely will keep a
slight mention in the forecast for the evening.
Friday morning model guidance brings another area of mid level
coverage northward into MN though model QPF continues to decrease
will have lowered pops from likely to chance. Will see more clouds
Friday morning with lows held up into the upper 50s to near 60
tonight. Friday afternoon and evening a gradual shift to the east
with shower activity is expected with an isolated chance for
showers or a thunderstorm to redevelop in the valley and across
eastern ND. Precip amounts will be light generally a tenth of an
inch or less.
.LONG TERM...(Saturday through Thursday)
Issued at 325 PM CDT Thu May 21 2020
Weather-related impacts are possible this weekend.
For the holiday weekend, look for highs in the 70s and 80s for
Saturday with 70s on Sunday. Looking at the synoptic setup, H5 low
pressure, situated in northern Saskatchewan, will bring a theta-e
gradient boundary across the CWA Saturday night. Preceding this, we
expect a chance for showers and thunderstorms during the afternoon.
Modest instability and shear will allow for a conditional threat of
severe thunderstorms, most likely starting in central North Dakota,
then progressing eastward through the afternoon and evening. Another
H7 low develops and moves across the Intermountain West late
Saturday evening. This will impact the area on Sunday with another
round of showers and thunderstorms. Ensemble guidance brings good
agreement to the overall pattern, but not to the instability profile
both Saturday and Sunday.
For Memorial Day, remnant shower and thunderstorm activity is
possible through the first half of the day for eastern North Dakota,
and through the early afternoon for our Minnesota counties. Overall,
Monday will be an improvement as far as precipitation is concerned,
with highs generally in the lower 70s across the entire region.
Overall, weather-related impacts will be minimal on Monday.
Nearly zonal flow prevails Tuesday and Wednesday, with an ensemble
signal for a trough passage as we head into Thursday. This will give
us a good chance at dry weather both Tuesday and Wednesday, with
highs in the 70s to near 80 degrees. Precipitation chances increase
Wednesday evening through late Thursday.
&&
.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
Issued at 649 PM CDT Thu May 21 2020
Virga and possibly a few light showers will continue to move
across eastern ND into northwest MN (very low coverage/impacts).
We can`t rule out an isolated thunderstorm, but so far this isn`t
not favored and chances/coverage do not warrant inclusion in TAFs.
Another round of light showers may develop into Minnesota later
tonight, but better chances would remain south of our TAF sites.
Strongest winds gusts will diminish early in the TAF period and
while winds will increase some Friday after sunrise the strongest
gusts would be 17-21kt (much lower than previous days). MVFR
conditions will once again overspread with good low level
moisture lingering across the region late tonight, before VFR
returns midday Friday. Isolated pockets of IFR conditions can`t
be ruled out in eastern ND 10-14Z, but confidence in ceilings
lower 1000 KFT AGL is low at this time.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...None.
MN...None.
$$
UPDATE...DJR
SHORT TERM...JK
LONG TERM...Lynch
AVIATION...DJR
Area Forecast Discussion
National Weather Service Huntsville AL
928 PM CDT Thu May 21 2020
.NEAR TERM...(Rest of tonight)
Issued at 928 PM CDT Thu May 21 2020
Widely scattered light-moderate shower activity associated with a
cutoff upper low that has been situated across the region for the
last couple of days continues to dissipate rapidly this evening.
However, as the cutoff low tracks slowly northeastward into the
Upper-OH Valley overnight, a weak mid-level shortwave disturbance
(currently across the southwestern AR) will become absorbed in its
circulation and accelerate northeastward, initiating the development
of deep convection along a warm front positioned across central
portions of MS/AL. Latest hi-res guidance suggests that this will
occur in the 06-08Z timeframe, with showers and thunderstorms
spreading northeastward into the local area between 08-12Z.
Forecast soundings depict a favorable combination of deep-layer bulk
shear in the 35-40 knot range and veering flow in the 0-3 km layer
to support organized storm structures during this period. That said,
it appears as if updrafts will be slightly elevated, and will likely
not begin to tap into the more unstable surface-based airmass until
the 12-18Z timeframe. Thus, we feel that a few strong storms capable
of producing frequent lightning, small hail and brief gusty winds up
to 40 MPH will be the main impacts early Friday morning. Otherwise,
the remainder of the forecast grids appear to be on track at this
point, although low temperatures have been increased slightly to
account for current trends and a gradual increase in low-level
moisture after Midnight.
.SHORT TERM...(Friday through Saturday)
Issued at 233 PM CDT Thu May 21 2020
As the warm front lifts into north AL, a plume of more unstable and
moist air in the warm sector should enable upscale growth of
clusters of ongoing convection. Deep layer bulk shear vectors will
remain rather modest at 25-30kt, but with CAPE values approaching
2000-2500 J/Kg by midday or early afternoon, continued development of
at least scattered thunderstorms along the warm front and/or outflow
boundary will persist into early evening before shortwave ridging
aloft builds in. The HRRR suggests the greatest risk during the
midday and early afternoon hours, while the WRF suggests an early
time with less certainty on the later convection. In either case, the
combo of strong instability and modest shear may yield strong to
perhaps a couple of severe thunderstorms in these clusters Friday.
There appears to be a nocturnal uptick in redevelopment of convection
by the models late Friday night due to a southwesterly LLJ/increase
impinging possible residual outflow from earlier in the day. So will
account for this as suggested blends indicate.
On Saturday, the ridging at 850-500 mb shifts just east of AL/middle
TN. The models indicate a very summer-like look to the synoptic
fields with no capping and moist unstable air in place. Weak MCVs are
abound in the model data, and should see another afternoon max of
scattered deep convection. Highs will warm into the l-m80s Saturday
afternoon.
.LONG TERM...(Saturday night through Wednesday)
Issued at 233 PM CDT Thu May 21 2020
There is pretty good confidence that the long wave pattern in the
long term portion of the forecast will be characterized (initially)
by an upper trough in the Intermountain West and a building ridge
along the East Coast. The global suite of models including ensembles
indicate the upper trough is likely to become closed off from the
polar westerlies early next week, while the TN Valley will probably
be situated along the western flank of the upper ridge in the East.
So, while confidence is pretty decent on the large scale features and
upper wave pattern through about mid-week next week, there is
relatively low confidence in specific timing and impacts of the
smaller scale features.
What is evident is a potential number of short wave troughs that
ride generally northward across the region during this period along
the trough/ridge interface. Among the most noticeable of these may
cross the area on Sunday, bringing a round of showers and
thunderstorms to the area at that time. Given the lack of strong flow
aloft and thus shear as well, very little storm organization is
expected. Although, the presence of weak steering currents, moderate
CAPE values and moderately high PWs will present a threat for some
locally heavy rainfall and gusty winds where stronger cells do occur.
Looking a little further ahead, the next short wave (albeit subtle)
may round the west side of the upper ridge and into our area on
Monday. Overall impacts from shower and thunderstorm activity look
similar to that on Sunday, with continued weak shear present. High
chance to likely POPs have been carried for most areas on these two
days. The pattern may ultimately continue unabated perhaps even into
the end of next week, with the possibility that the upper low will at
least partially close and meander across the Southern Plains, while
the upper ridge holds on strong to our east. This would tend to keep
the region in southerly flow at/near the surface and ensure generally
warm/humid conditions throughout.
&&
.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
Issued at 656 PM CDT Thu May 21 2020
VFR conditions will exist at the HSV/MSL terminals overnight, with a
scattered layer of stratocu based arnd 3500 ft AGL beneath broken
altostratus. The stratocu layer will slowly become broken during the
early morning hours on Fri, as a warm front begins to approach the
region from the southwest. Lift to the north of the warm front and to
the east of a mid-level disturbance approaching the TN Valley should
result in an initial increase in convection invof the terminals btwn
08-10Z, with TSRA becoming fairly widespread btwn 13-19Z, when
PROB30 groups have been introduced for TSRA and MVFR cog/vsby
reductions. Storms will shift northeastward with the warm front
during the afternoon, with conditions improving at the airports btwn
17-19Z. Winds will veer to SSW and increase to arnd 10 knots in the
wake of the warm front.
&&
.HUN WATCHES/WARNINGS/ADVISORIES...
AL...NONE.
TN...NONE.
&&
$$
NEAR TERM...70/DD
SHORT TERM...17
LONG TERM...KDW
AVIATION...70/DD
For more information please visit our website
at weather.gov/huntsville.
Area Forecast Discussion
National Weather Service Lincoln IL
926 PM CDT Thu May 21 2020
.SYNOPSIS...
Issued at 330 PM CDT Thu May 21 2020
Weak high pressure in the eastern Great Lakes will finally allow
for a little bit of sunshine across the Midwest on Friday. This
will allow temperatures to climb to more seasonal levels in the
lower to middle 70s. A weather disturbance from the Plains will
move toward the Great Lakes region Friday night, bringing us our
next chance for showers and thunderstorms. The holiday weekend
outlook has much warmer temperatures in store for central and
southeast Illinois, along with periodic chances for a few
thunderstorms.
&&
.UPDATE...
Issued at 924 PM CDT Thu May 21 2020
A corridor of clearing has developed in the clouds across our
eastern counties, but HRRR and RAP guidance are indicating clouds
from our SW area will begin to shift northward the rest of the
night. Breaks will still be present, so some fog could begin to
form due to the light and variable winds. The models are not
jumping on the fog bandwagon just yet, but our recent period of
rainy conditions could manifest in some fog later tonight. Went
ahead and added fog as a result.
Drizzle is the other concern tonight, with our NE counties having
the best chance of being under the lower ceilings and light
synoptic lift. Most areas should remain dry, so very minimal
impact even if some patchy drizzle does occur.
Updated sky and weather grids as needed to match those
trends/possibilities.
&&
.SHORT TERM...(This evening through Friday)
ISSUED AT 330 PM CDT Thu May 21 2020
The pesky upper low which has plagued our area with periods of
rain, clouds and cool temperatures is finally losing its grip on
our weather. Early this afternoon the upper low was centered in
western KY. An upper level shortwave in the central Plains is
expected to lift toward Iowa Friday night, which will help kick
the upper low eastward. An increasing southerly flow on Friday
will result in more seasonal high temperatures in the mid 70s
along with more breaks in the clouds from late morning into the
afternoon.
.LONG TERM...(Friday night through Thursday)
ISSUED AT 330 PM CDT Thu May 21 2020
A rather active weather pattern is in store for central and
eastern Illinois from this weekend into the middle of next week
with above normal temperatures and periodic chances of showers and
t-storms. An upper level ridge is expected to build along the
Appalachians in the wake of the departing upper low. Upper level
troughing will deepen in the Plains late this weekend, before
cutting off from the upper level flow by midweek. This will keep
us in a deep south to southwesterly flow through the long term
period. The most noticeable feature will be daily high
temperatures well into the 80s with higher levels of humidity,
which will be quite the contrast from the recent cool, damp
weather.
The highest potential for showers/t-storms this weekend will be
Friday night into Saturday morning with the short wave lifting
northeastward and low level warm advection, and again on Memorial
Day as the upper ridge axis shifts east of the state. On Sunday,
we cut way back on the PoPs due to the proximity to the upper
ridge and warmer, capping air aloft. With enough sun and warm low
level temps, Sunday looks to be the warmest day of the year thus
far with highs possibly reaching the upper 80s in spots.
For Tuesday through Thursday it will difficult to time subtle
shortwaves to provide forcing for thunderstorms as we remain in a
warm sector with high instability but low shear. There is somewhat
general agreement that Tuesday and again on Thursday the higher
chances for convection may occur, but the confidence is quite low
this far out. Highs in the lower/middle 80s with lows in the
middle/upper 60s will definitely make it feel like summer has
arrived.
&&
.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
Issued at 632 PM CDT Thu May 21 2020
Brief VFR conditions will occur across central Illinois this
evening, before ceilings drop back to MVFR later tonight, and
possibly even IFR in eastern IL. MVFR fog will also be possible,
as surface winds become light and variable amid increasing surface
dewpoints. We can`t rule out some patchy dense fog, but
confidence is low that fog that thick would affect any TAF site.
The upper level low is expected to finally get a kick to the east
on Friday ahead of an approaching shortwave trough in the central
Plains. This will allow for some breaks in the clouds, although
the majority of the morning hours will remain at MVFR levels
across central and eastern IL.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...Shimon
SYNOPSIS...Miller
SHORT TERM...Miller
LONG TERM...Miller
AVIATION...Shimon
Area Forecast Discussion
National Weather Service Lubbock TX
617 PM CDT Thu May 21 2020
.AVIATION...
Iso TS possible in the first few hours of the TAF period at KCDS
and will monitor for inclusion of a mention. Otherwise, VFR
conditions are likely through Friday.
&&
.PREV DISCUSSION... /issued 230 PM CDT Thu May 21 2020/
SHORT TERM...
Flow aloft has become more southwesterly in response to a large
upper level low encompassing much of the western CONUS. At the
surface a lee-side low has begun to develop in northeastern NM
with surface winds turning southwesterly across the western
portions of the CWA. This flow will advect warm dry air across the
area and warm high temperatures into the 90s. Thanks to the SW
flow aloft and at the surface the dryline is more east today and
somewhere near the edge of the Caprock Escapement. To the east of
the dryline afternoon convection will be highly conditional while
west fire weather will be the main concern. Capping, the lack of
mid-level moisture and missed timing of the upper level shortwave
moving eastward will all limit chances for dryline convection
this afternoon. However, forecasted MUCAPE values are over 2000
J/kg with shear values near 40 kts and steep low-mid level lapse
rates all suggest that if a parcel can persist through the dry
environment severe thunderstorms with rotation will be possible.
Steep lapse rates and DCAPES over 1000 J/kg suggest that strong
wind gusts up to 70 mph and large hail up to 2 inches will be
possible. Additionally, a tornado risk can not be ruled out given
the presences of an increasing low level jet this evening and
increased EHIs. The HRRR is now showing a few possible storms
across the far southeastern counties where better dewpoints will
reside. Current satellite pictures are showing small cumulus
fields develop just along the dryline but, the CU come down as
fast as they go up leading us to believe the mid-levels may be in-
fact too dry. We have gone ahead and lowered PoPs across the
Rolling Plains into the slight chance category but not eliminated
them. It is mid May and as the past few days have illustrated
severe weather is possible no matter what.
Tonight into tomorrow should be relatively quite weatherwise. A weak
front will be forced into the northern portions of the CWA early
tomorrow morning as an upper level storm moves through the High
Plains. This front will do little in the way of affecting our area
except for shifting the winds to the north for the first portion
of the day. By tomorrow afternoon, W-SW surface flow returns with
dry and warm weather.
LONG TERM...
The western trough that is currently in the process of reloading,
will eject across the northern High Plains late Sunday, while a
portion of it digs southeastward through the Four Corners region.
The more southern energy is forecast to close off into a cut off
low, potentially hanging out over or near West Texas through much of
next week.
Before this occurs, a dryline will be vacillating within the
South/Rolling Plains the next few days, beneath westerly to
southwesterly flow aloft. The dryline will be joined by a weak
cold front that may dip into the CWA tomorrow, in response to a
shortwave trough swinging by to our north early in the day. Either
the dryline, or the triple point will probably be positioned
somewhere near the far southeast corner of the CWA tomorrow
afternoon/evening, where it could provide sufficient focus/forcing
for late-day CI. Should storms develop, very strong instability
and sufficient wind shear would support a definite severe weather
risk. Saturday will bring more of the same, but the dryline is
expected to be further west in response to backing flow aloft and
dropping pressure in the lee of the central/southern Rockies.
Hence, the conditional severe weather risk will encompass the
eastern half or two thirds of the CWA Saturday afternoon. Sunday`s
setup will be fairly similar to Saturday, except that the
approaching western trough will provide more favorable upper level
dynamics, make convective development more likely during the
afternoon/evening. Again, environmental parameters will be solidly
supportive of a severe weather risk along and ahead of the
dryline.
The northern stream portion of the system will send a cold front
southward, though most guidance now delays its arrival until Monday.
Depending on the timing of the front, this could provide an
additional focus for storm development early next week. After that,
it is beginning to appear more likely that the developing cut off
low will linger overhead or nearby through much of next week. If
this proves true, much/all of next week would be relatively cool
and moist with periodic chances of showers and generally sub-
severe thunderstorms.
FIRE WEATHER...
West of the dryline conditions will be favorable for fire weather as
flow aloft and at the surface become SWRLY with the development of a
lee-side surface low this afternoon. The warm/hot, breezy and very
dry southwesterly winds will create elevated to briefly critical
fire weather. Where rain hasn`t fallen in the past few days, across
the western South Plains and far southwest Texas Panhandle, fuels
will be more receptive to fire starts. Thus, an RFD has been issued
roughly along and west of a Friona to Olton to Brownfield line,
valid from noon until 9 PM.
&&
.LUB WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
07
Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
934 PM EDT Thu May 21 2020
.SYNOPSIS...
Low pressure over the Carolinas will slowly move north towards
the Chesapeake Bay through Friday night, then move east out to
sea. High pressure builds into the region Saturday through
Memorial Day and persists through mid-week.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
01Z regional radar shows scattered showers, some heavy, moving
through the north-central Virginia Piedmont. KCHO ASOS reported
0.21" between 00-01Z. These showers are moving towards the NW as
surface low pressure over the Carolinas starts moving north
towards the Chesapeake Bay region overnight. Convective activity
ongoing attm over central NC in unstable air is expected to
stratify as it crosses the VA/NC border. This should continue to
move NW, and provide the piedmont with additional rainfall
overnight. The FF Watch was cancelled earlier this evening after
analysis and trends of the 12Z EPS, the HRRR trends, and the
12Z HREF. One-hour and 3-hr FFG seemed to be too high of a bar
to support flash flooding overnight, especially on the stable
side of the surface low.
Ironically, the instablity does work it`s way into the southern
part of the CWA before dawn, but it comes in after the end time
of the cancelled watch. At that time, it is believed that any
convective elements will be isolated and elevated, and there
would be enough time to allow drainage from the previous
rainfall. However, I did include thunder in the forecast for the
southern waters of Maryland`s Chesapeake and St. Mary`s County.
Thunder may have to be expanded up the I-95 corridor in and
around Fredericksburg.
Otherwise, the story overnight will be showers increasing in
areal coverage across the entire CWA as stronger convective
elements in the unstable air mass over NC moves into the more
stable air north of the VA/NC border.
Overnight low temps will be milder than normal, with dewpoints
in the mid 50s on E/SE fetch originating over the Gulf Stream
off Cape Hatteras.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH SATURDAY NIGHT/...
Upper level low and surface low will be moving into the Mid-Atlantic
through the day Friday. A band of rain will still be over our area
during the first half of the day Friday as it progresses north and
east along with the upper level low. As this rain band moves away
and clouds break west of it, along with some instability and lift,
could see a few thunderstorms developing Friday afternoon, mainly
over Central Virginia and the Potomac Highlands. High temperatures
will be between the mid 60s and upper 70s. Surface and upper level
lows will move east and offshore on Friday night, but a chance of
rain showers remain. Low temperatures will be in the 50s and 60s.
Upper level low will be pushing offshore early Saturday as
conditions continue to dry over our area, however upper level energy
behind this system and some instability could produce afternoon
thunderstorms on Saturday. High pressure will start building over
our region Saturday night along with ridging aloft.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
Mid to upper level ridging will take hold the second half of the
holiday weekend as surface high pressure off the New England coast
stretches a ridge down into the Mid-Atlantic region. As ridging
begins to build, some linger upper level energy could be enough to
spark some afternoon showers/storms across the Potomac/Allegheny
Highlands. Otherwise, dry conditions and temperatures in the low to
middle 70s expected.
Continued dry conditions for your Memorial Day and into Tuesday as
the upper ridge crests over the Mid-Atlantic and the ridge of high
pressure remains strong over the Eastern Seaboard. Temperatures and
humidity will tick upwards given southerly flow around the high to
our east. With diurnal heating and increasing moisture, our mountain
zones will reside on the western fringes of the surface ridge, with
low end chance showers/storms possible both Monday and Tuesday
afternoons.
Better chance of rain comes Wednesday afternoon and evening as the
high to our east nudges further eastward into the Atlantic and a
weak shortwave tracks to our north. Temperatures will rise into the
80s with dewpoints in the 60s, so a bit better ingredients to
support higher shower/storm chances during this time.
&&
.AVIATION /01Z FRIDAY THROUGH TUESDAY/...
IFR to LIFR due to VSBYs and CIGS are expected at all terminals
after midnight, lasting well into Friday morning. Conditions
will improve to VFR late on Friday with a chance of showers
remaining, maybe a TSRA and a passing showers into Friday
night. VFR on Saturday with afternoon TSRA possible.
VFR conditions expected to persist at the terminals Sunday through
Memorial Day as a ridge of high pressure at the surface and ridging
aloft take hold. Winds will remain light and out of the ESE at less
than 10 knots.
&&
.MARINE...
Winds will be below SCA threshold overnight under a strong
inversion of warm air over colder water. Winds will become
NW on Saturday through Saturday night.
High pressure building at the surface and aloft will maintain sub
SCA conditions over the waters Sunday through Memorial Day as light
east southeast winds prevail.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...None.
MD...None.
VA...None.
WV...None.
MARINE...None.
&&
$$
SYNOPSIS...Lee
NEAR TERM...Lee
SHORT TERM...IMR
LONG TERM...BKF
AVIATION...Lee/BKF
MARINE...Lee/BKF
Area Forecast Discussion...CORRECTED
National Weather Service Springfield MO
900 PM CDT Thu May 21 2020
.SHORT TERM...(This afternoon through Friday morning)
Issued at 301 PM CDT Thu May 21 2020
Early this afternoon, a cut-off upper level low is spinning in
place across the lower Ohio River valley due to being situated in a
Rex block pattern. As a result, some broken low level cloud cover is
lingering across portions of central Missouri and the eastern
Missouri Ozarks, while portions of southwest Missouri have seen some
mixed clouds and sunshine behind this feature.
The Rex block will continue to break down the remainder of today
as the cut-off upper low slowly drifts northeastward. However, a
shortwave over Oklahoma is already making it`s way towards our
area. Some instability and increasing moisture will continue to
move in with this feature during the remainder of the afternoon
and into the evening, keeping the ongoing scattered showers and
thunderstorms going across southeast Kansas and western Missouri.
This convection should diminish by mid to late evening as
instability wanes towards sunset. No severe weather is expected
with this activity.
We should see a relatively quiet period tonight as more organized
storm development remains to our west over portions of Kansas. CAM
model solutions are coming into better agreement with decaying
remnants of this overnight convection moving into southeast Kansas
and western Missouri by the early morning tomorrow and pushing
across our area from west to east throughout the morning hours.
We can`t rule out a few damaging wind gusts and perhaps low end
hail potential with this convection as it gets into western
portions of our area, but it is expected to weaken as it moves
across Missouri, as environmental instability decreases with
eastward extent.
.LONG TERM...(Friday through Wednesday)
Issued at 301 PM CDT Thu May 21 2020
The threat for strong to severe storms tomorrow afternoon and
evening will be dependent on how long the decaying morning
convection remains in the area, as lingering cloud cover could
hamper instability. However, the synoptic set up will still be
favorable for more organized convection during the afternoon and
evening given a low-level jet and sufficient deep-layer shear in
addition to surface temperatures near 80 degrees and dewpoints in
the 60s. CAM model solutions are still in some disagreement on the
locations and storm modes of the forecast convection, with the
NAM Nest hinting at a multicell cluster while the HRRR suggests a
few supercells developing. Initiation during this timeframe will
most likely be along a remnant outflow boundary from the morning
storms. Any strong to severe storms that may develop would be
capable of large hail and damaging winds, while the low end threat
for a few tornadoes would mainly hinge on whether or not the
storm mode is supercellular. The best chances for the severe
thunderstorm risks will be across southeast Kansas and portions of
western Missouri west of the Highway 65 corridor.
The heavy rain threat for Friday will be best realized for
locations where both the morning and later Friday round of storms
move through. Generally speaking, around 0.5-1 inch of rain will
be possible between the two rounds of storms, though isolated
amounts upwards of two inches would not be out of the question in
areas of training thunderstorms. Therefore, there is still a
threat for flooding potential on Friday given this forecast
rainfall falling on relatively saturated soils from last week.
Saturday looks to be the "quietest" day of the coming weekend as
some brief shortwave ridging will be in our vicinity between
Friday`s shortwave and additional embedded shortwaves to our west
in the southwest flow aloft. Significant instability will be
present under this feature across the region on Saturday afternoon
and evening, though shear and forcing for ascent look too
marginal to support organized convection. Saturday will also
likely be the warmest day of the weekend, with the entire region
seeing high temperatures in the low to mid 80s.
The second active period in the extended forecast will arrive on
Sunday through Tuesday as the large-scale upper level trough
finally approaches from our west, moving shortwave energy across
the area and bringing daily showers and thunderstorms.
Additionally, multiple medium-range models suggest this feature
transitions into a cut-off low across the southern Plains and
becomes separated from zonal flow over the northern CONUS during mid
to late next week. This would keep the active, wet weather
pattern lingering across the Missouri Ozarks through at least late
next week if it comes to fruition.
Overall, expect a widespread 2-3 inches of rain west of the
Highway 65 corridor and 1-2 inches to the east, with locally
higher amounts possible from training convection during the next 7
days. Additional flooding risks will be possible along with this
heavier rainfall, as well.
&&
.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
Issued at 649 PM CDT Thu May 21 2020
Timing, coverage, and intensity of convection are the primary
concerns for this forecast period. Models show scattered showers
and storms starting tonight, with a line of strong to potentially
severe storms moving west to east across the area Friday morning
and early afternoon. Additional scattered showers and storms are
possible behind that line.
&&
.SGF WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
&&
$$
SHORT TERM...Rothstein
LONG TERM...Rothstein
AVIATION...Titus
Area Forecast Discussion
National Weather Service Tulsa OK
941 PM CDT Thu May 21 2020
.DISCUSSION...
Showers and thunderstorms that affected parts of northeast
Oklahoma and far northwest Arkansas this afternoon and evening
have just about moved out of the area at this time. A few isolated
showers remain, but have lowered pops in some places for the rest
of the evening.
A developing MCS across southwest Kansas is expected to move east
southeast into parts of northeast Oklahoma by around sunrise. The
latest runs of the HRRR suggest scattered showers and storms will
also develop later tonight out ahead of this complex across parts
of the area, so have left pops alone for later tonight.
Update on the way.
&&
.TSA WATCHES/WARNINGS/ADVISORIES...
OK...None.
AR...None.
&&
$$
SHORT TERM...23
LONG TERM....05
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