Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 04/06/19
Area Forecast Discussion
National Weather Service Columbia SC
809 PM EDT Fri Apr 5 2019
.SYNOPSIS...
Drier air will briefly build over the region tonight into
Saturday with mainly afternoon showers on Saturday in the CSRA
and southern Midlands. Another low pressure system will
approach the region early next week resulting in numerous
showers and thunderstorms at times, especially Monday. Dry and
warm conditions expected Wednesday and Thursday behind the
system.
&&
.NEAR TERM /UNTIL 7 AM SATURDAY MORNING/...
Satellite imagery shows some clearing in the CSRA and southern
Midlands continuing to move northward. Expect the clearing to
move through the entire forecast area over the next couple of
hours...however low level moisture will remain plentiful
overnight. Winds will be light and variable overnight and with
dry air noted in model soundings conditions for fog/stratus will
be favorable. As such expect clouds and fog to develop across
the northern and central Midlands around midnight then expand
southward into the southern Midlands and CSRA through the early
morning hours. Areas of fog are expected over the entire
forecast area by daybreak. Developing clouds and fog will limit
radiational cooling with overnight lows generally in the low to
mid 50s.
&&
.SHORT TERM /7 AM SATURDAY MORNING THROUGH SUNDAY NIGHT/...
Saturday...Areas of fog expected around daybreak with dry air
aloft and shallow low-level moisture. Nearly stationary front
across south central Ga in the morning with surface Ridging
across the Carolinas. The focus for showers early in the day
mainly south of the CWA near the front. In the afternoon, the
front appears to drift north near the CSRA and weak isentropic
lift noted. Weak to moderate instability develops as low level
moisture increases. Lift mainly across the southern or southeast
CWA and there may be a weak short wave trough moving through
around midday. Will continue isolated to scattered
showers/thunderstorm in the CSRA and south Midlands mainly in
the afternoon. Temperatures will be tricky, with considerable
clouds in the south and some clearing north. Northeast low level
flow and surface based inversion early, temperatures may be
slow to rise. Large range in temperature guidance with nam much
cooler than gfs 2m temps. Blended temp guidance has lowered from
previous run so went cooler.
Saturday night...Although moisture continues to increase across
the area, think convection will be diurnal with upper ridge
building in behind weak short wave trough. Any showers should be
isolated and mainly near the frontal boundary. Temperature
blend guidance accepted.
Sunday and Sunday night...Increasing moisture across the area
with resulting moderate instability across the area. Frontal
boundary likely moves into the area with resulting convergence.
Front should provide focus for scattered showers and
thunderstorms. Coverage may be highest in the Piedmont with
ridge centered offshore. Convection expected to be diurnally
driven so pops diminishing after 00z. Temperatures well above
normal with max temps near 80 and lows in the 60s.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
Highly amplified upper trough and surface low will be off to
the west to start off the week. ECMWF and GFS in good agreement
through the longer term. Each show more of an open trough moving
through the Deep South toward midweek. Low pressure system in
the southern Plains early Monday will move east across the
southern Mississippi Valley. Deep moisture from the Gulf of
Mexico will spread northeast into the area. Expect precipitable
water increase to around 1.6 inches in the afternoon. With
deeper moisture across the area and resulting moderate
instability, expect widespread showers and thunderstorms by
afternoon. The models hint at convection in the evening possibly
enhanced by increasing deep layer shear to the west.
Scattered showers and thunderstorms Tuesday as upper level
trough moves through the area and steep low to mid level lapse
rates. Very cold temperatures at 500 mb around -20C. Drier
conditions by Wednesday.
Temperatures during this period will be above normal through
this period with highs in the 70s and 80s and lows in the 50s to
lower 60s.
&&
.AVIATION /00Z SATURDAY THROUGH WEDNESDAY/...
High confidence for restrictions developing after 06Z.
Abundant low level moisture combined with dry air aloft, clearing
skies early this evening and light to near calm winds will
provide favorable conditions for fog/stratus to develop. HRRR
and MOS guidance in agreement showing IFR stratus developing
across the northern and central Midlands around 06z then
expanding southward over central Georgia by 09z with MVFR/IFR
cig/vsby. Have continued restrictions by 07z all terminals with
both fog/stratus expected.
Some weak isentropic lift will develop over the top of the
stalled front to our south early Saturday and could result in
isolated showers but chances to low to include in the forecast.
Cig/Vsby restrictions should improve during the 14z-16z time
frame, returning to VFR during the afternoon. AGS/DNL may be a
bit delayed due to possible showers and their proximity to the
front. Light and variable winds overnight becoming northeast
around 5 knots after 14z then veering southeast during the
afternoon.
EXTENDED AVIATION OUTLOOK...There will be periods of MVFR or IFR
conditions through Tuesday associated with a frontal system in
the region.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
GA...None.
SC...None.
&&
$$
Area Forecast Discussion
National Weather Service Cheyenne WY
555 PM MDT Fri Apr 5 2019
.UPDATE...
Issued at 547 PM MDT Fri Apr 5 2019
...Please see latest 0Z aviation discussion
&&
.SHORT TERM...(This evening through Saturday)
Issued at 254 PM MDT Fri Apr 5 2019
A few light showers have begun to develop across southeast Wyoming
under southwest flow from the approaching trough. Current visible
imagery shows widespread cumulus coverage over the area, however
low MLCAPE values around 200-500 J/kg have resulted in minor
vertical development for the majority of these cells. Scattered
showers will continue to develop late this afternoon and into this
evening with isolated thunder possible, especially along the
northern Nebraska Panhandle where instability is greatest. RAP
soundings indicate an elevated Inverted-V profile with DCAPE of
~600 J/kg suggesting the potential for dry microbursts through
early evening. Otherwise, main threats will be gusty winds up to
40 MPH and small hail with the strongest storms through 06Z
Saturday.
Warmer weather will continue on Saturday with highs in the 60s on
the High Plains and in the upper 40s for the mountains. Scattered
rain showers with a few rumbles of thunder are also possible
across the region Saturday afternoon and evening with an
approaching cold front. CAPE values look to be slightly higher
on Saturday nearing 1000 J/kg, however shear will remain low and
not support much organized convection.
.LONG TERM...(Sunday through Thursday)
Issued at 345 AM MDT Fri Apr 5 2019
Mild and dry conditions return Sunday and Monday under westerly flow
aloft. Showers develop late Monday night along and west of a Douglas
to Rawlins line, and spread east into southeast WY and northern NE
Panhandle Tuesday. The next Pacific low pressure trough will be a
progressive system, with widespread rain and higher elevation snow
showers Tuesday night and Wednesday. Both the GFS and ECMWF are in
better agreement with track of the upper low over southern WY and
northern CO Wednesday morning, and southern NE and northern KS
Wednesday afternoon. Surface low intensifies to 984mb over northeast
CO by 12Z Wednesday, and 980mb along the NE/KS border by 18Z Wednesday.
Despite being a progressive system, there is the potential for
significant precipitation with up to an inch of liquid precipitation.
Confidence is low to moderate on location and timing of snowfall.
Snow levels may lower to 4500 feet Wednesday. Northerly winds may
gust as high as 40 mph over the southeast WY plains and southern
NE Panhandle Wednesday. Showers decrease in coverage Thursday. High
temperatures Wednesday and Thursday will average 10 to 15 degrees
below normal with highs in the mid 30s to mid 40s.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 547 PM MDT Fri Apr 5 2019
The main concern across southeast Wyoming and the Nebraska
panhandle is elevated showers above dry air at the surface. This
could cause gusty and erratic winds near shower activity through
this evening. Did not have enough confidence to put microbursts in
the TAF, but it is possible. The weather will settle as we move
into tonight and VFR conditions are expected for the remainder of
the period.
&&
.FIRE WEATHER...
Issued at 240 AM MDT Fri Apr 5 2019
Fire weather concerns will remain low due to saturated soils and
fuels. Warmer than normal temperatures will continue today with
widely scattered showers and thunderstorms. This weekend will be
breezy and mild, with scattered showers and isolated thunderstorms
Saturday. Minimum relative humidities will average 25 to 30
percent through the weekend. Sunday and Monday will be mild and
dry. Cooler temperatures, rain and snow showers will return
Tuesday through Wednesday.
&&
.HYDROLOGY...
Issued at 254 PM MDT Fri Apr 5 2019
Despite warm conditions Friday, water will be slow to recede with
more precipitation Friday afternoon through Saturday evening from
scattered rain showers. Saturated soils will persist with
remaining snow drifts melting and additional rainfall. The
extended forecast indicates the potential for more rain and snow
the middle of next week that will keep water levels high. For the
latest information regarding flooding across Box Butte County and
portions of Dawes County, please see the latest Areal Flood
Advisory.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...None.
NE...None.
&&
$$
UPDATE...CW
SHORT TERM...MB
LONG TERM...MAJ
AVIATION...CW
FIRE WEATHER...MAJ
HYDROLOGY...MB
Area Forecast Discussion
National Weather Service Dodge City KS
605 PM CDT Fri Apr 5 2019
...Updated aviation discussion...
.SHORT TERM...(This afternoon through Saturday night)
Issued at 1145 AM CDT Fri Apr 5 2019
Despite plenty of cirrus, temperatures were warming up rapidly
through the 60s at midday, on the way to the 70s this afternoon.
12z NAM deepens a 999 mb surface leeside low east of Denver this
afternoon, resulting in about 9 mb of mslp gradient across
SW KS. S/SE wind gusts of 30-40 mph will be common through sunset,
with gusts already near 40 mph at Garden City late this morning.
Moisture advection will continue this afternoon with dewpoints
holding in the lower 50s, contributing to modest CAPE and lifted
indices through this evening. With no forcing available, forecast
will remain dry through this evening.
Rather vigorous shortwave over NW Mexico at midday will swing
rapidly into SE New Mexico late tonight/early Saturday. As dynamic
lift ahead of the shortwave arrives, with plenty of moisture
available, showers and thunderstorms will develop across W TX and
the TX panhandle after midnight. At least some of this activity
will spread into the southern zones through Saturday morning, with
12z NAM being one of the most aggressive solutions bringing
potentially heavy rain into SW KS. With other models also
depicting measurable QPF, increased pop coverage, but further
increases to the likely category may be needed especially Saturday
morning. Clouds, moisture advection and elevated south winds will
keep temperatures mild through sunrise Saturday, mainly in the
lower 50s.
Scattered showers and thunderstorms are expected to persist/favor
the eastern zones throughout daylight Saturday as the shortwave
works its way into Kansas. Moisture and instability will certainly
be there to support further convective development through the
day, with dewpoints in the lower 50s, CAPE of 1-2000 J/kg, and
lifted indices to -5C. But the key to how much convection
redevelops, and how strong it will be, will be tied to airmass
recovery behind the morning rain/storms. For what it`s worth, long
range HRRR shows convective redevelopment Saturday afternoon, in
an area with healthy EHI values. On the other hand, shortwave
timing does not look favorable, with most of the forcing leaving
SW KS by peak heating, and subsidence resuming. Perhaps the best
chance of strong/severe convection will be across the SE zones
near Medicine Lodge Saturday afternoon, but again only if there is
time to recover from widespread morning convective overturning.
Pops are warranted for most zones through daylight Saturday, with
SPC 5% wind/hail probabilities for all of SW KS. With clouds and
precipitation, temperatures will held to the 60s for most
locations.
.LONG TERM...(Sunday through Friday)
Issued at 235 PM CDT Fri Apr 5 2019
Sunday through Tuesday will feature an extended period of quiet,
dry fantastic spring weather. Rising heights will support a
warming trend each afternoon Sunday and Monday, through the 70s.
Breezy north winds on Sunday, followed by much lighter winds on
Monday.
Tuesday will be the warmest day of the week. Flow aloft becomes
zonal, as a powerful trough digs into the northern Great Basin.
Associated lee cyclogenesis will begin Tuesday afternoon across
NE Colorado, with ECMWF placing a 990 mb surface low east of
Denver 7 pm Tuesday. A sharpening dryline will extend southward
to West Texas, but all indications are the atmosphere will remain
capped and quiet Tuesday. All locations will approach 80 degrees,
with SW locales more than likely warming well into the 80s. Some
of the warmest temperatures so far in 2019 expected on Tuesday.
Models remain consistent, portraying an intense extratropical
cyclone traversing Kansas and the central plains in the Wednesday
time frame. 12z ECMWF and the model consensus forecasts an intense
surface low to track across northern Kansas on Wednesday. This
synoptic evolution would spread a significant snowstorm across
Nebraska, keep any convection well to our east, and strongly
dryslot SW KS. There is still plenty of time for a more southward
trajectory to evolve in the models, but this outcome is most
likely. High wind warning criteria is likely (40 mph sustained,
gusting 58 mph) on Wednesday. Current solutions would argue for
the strongest winds to be NWly post-frontal Wednesday afternoon.
Model blend included a mention of rain/snow across the northern
zones late Wednesday and Wednesday night for wraparound
precipitation. These pops were retained, with the best chance of a
wet snow accumulation along the I-70 corridor Wednesday night.
Again, we will continue to be vigilant for a storm track change,
as this storm will be intense and its impacts significant.
Much colder air will pour in on Thursday, with afternoon
temperatures struggling into the lower 50s. Current forecast from
the blend is likely not cold enough, with ECMWF keeping us in the
40s.
A hard freeze is now expected Friday morning, with a 1030 mb
Canadian surface high settling over Kansas around sunrise. Again,
going forecast of lows near freezing is likely not cold enough,
with widespread 20s likely. ECMWF suggests lows of 22-24 are
likely, with coldest locales in the teens. Early gardeners are
reminded that the growing season has not yet begun.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 605 PM CDT Fri Apr 5 2019
An upper level disturbance will move northeast out of New Mexico
this evening and across the central High Plains late tonight and
Saturday. Chances for showers and isolated thunderstorms will
increase across southwest and central Kansas later tonight into
Saturday. The best chances for precipitation will be through late
Saturday morning into the afternoon hours. Areal coverage of the
precipitation does not look too widespread at this time so will
keep prevailing VCSH in the terminals. There could be some
potential for a period of MVFR cigs accompanying the showers.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 54 68 49 71 / 40 60 30 10
GCK 52 69 47 69 / 20 30 20 10
EHA 46 71 46 70 / 30 10 10 10
LBL 51 71 49 70 / 50 30 20 10
HYS 56 68 49 72 / 10 50 50 10
P28 56 69 52 73 / 40 60 30 10
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...Turner
LONG TERM...Turner
AVIATION...Gerard
Area Forecast Discussion
National Weather Service Austin/San Antonio TX
1001 PM CDT Fri Apr 5 2019
.UPDATE...
The 500 mb trough axis currently resides from near the Mexico/AZ/NM
border and extends south into northern Mexico. Fairly robust deep
convection is ongoing from around Midland to just southeast of
Lubbock, with several severe thunderstorm warnings currently in
effect. It has been a fairly quiet evening across our region, however.
One lonely thunderstorm managed to develop near the Rio Grande west
of Langtry and is currently tracking across northern portions of Val
Verde County, and has not managed to come particularly close to
reaching severe criteria. In fact, it continues to weaken as it heads
northeast into a less favorable environment.
Perusing the most recent high-resolution and convection allowing
models, the 00z run of the 3 km NAM has backed off from developing
the robust squall line in the early morning hours that the 18z run
had developed. The HRRR continues to only develop some showers across
the region through much of the overnight period before finally
initiating some stronger storms out west across portions of the
southern Edwards Plateau/Hill Country by mid morning. However, these
are short-lived, and the HRRR continues to show the Austin and San
Antonio metro areas largely missing out on showers and thunderstorms
tomorrow altogether. The RAP, however, does develop fairly widespread
convection across the region tomorrow morning and into the early
afternoon hours, with respectable QPF totals (some areas above 2
inches), especially just west of Austin. In summary, there is still
quite a bit of uncertainty in how this system is going to develop and
evolve given the lack of a strong surface forcing mechanism like a
cold front.
Went ahead and made a few edits to the grids. Reduced PoPs for much
of the region in the 1 AM to 7 AM time period, especially for areas
along and east of I-35. It still looks looks like the best chances
for widespread showers and thunderstorms for much of the region,
especially the I-35 corridor and the Austin and San Antonio metro
areas, will be from 7 AM to about 1 PM tomorrow. Only made slight
edits to the PoP grids for this time frame, only trimming back PoPs
for locations south and southwest of San Antonio. Strong to severe
thunderstorms remain possible. SPC continues to keep our region under
a slight risk for severe thunderstorms. Primary hazards would be
strong winds and large hail, with a minimal tornado threat.
&&
.PREV DISCUSSION... /ISSUED 705 PM CDT Fri Apr 5 2019/
AVIATION...
The main concern this forecast period is convection at all sites.
Model solutions vary widely, but many point toward the 17Z-22Z period
on Saturday as the best chances for TSRA, except for earlier at KDRT,
from 06Z-12Z. Look for MVFR-IFR CIGS after 05Z at KAUS/KSAT/KSSF,
with MVFR CIGS at KDRT. Look for convection to end around 00Z Sunday,
however expect additional -SHRA/-TSRA beyond the forecast period into
the day on Sunday.
PREV DISCUSSION... /ISSUED 329 PM CDT Fri Apr 5 2019/
SHORT TERM (Tonight through Saturday Night)...
Visible satellite imagery this afternoon shows an agitated cumulus
field developing across the Rio Grande Plains with ample heating
allowing for temperatures to rise into the mid to upper 80s along the
Rio Grande. As forcing for ascent continues to overspread the region
ahead of a disturbance over southern Arizona/ northern Mexico later
this afternoon and evening, high resolution guidance has remained
consistent in an isolated thunderstorm or two developing across the
higher terrain of Mexico and quickly propagating towards Val Verde
County. Loss of heating will result in this first, initial round of
activity quickly tapering off by mid-evening and expect the region to
remain rain-free this evening.
Deepening lee side troughing over the High Plains in response to the
approach of the upper level disturbance is expected to result in a
secondary round of thunderstorm development across West/West Central
Texas into the Edwards Plateau and possibly as far south as the Rio
Grande Plains overnight. The southern extent of development remains
somewhat uncertain as the 12Z suite of model guidance remains varied
on where the greatest lift will be realized across the western half
of the state... and this is resulting in model solutions overnight
indicating everything from thunderstorm activity remaining well north
of the region to a broken line of thunderstorms propagating from the
west/southwest towards Interstate 35 during the morning hours.
What does appear to be certain at this point is that rain chances
Saturday will be heavily dependent on what happens overnight. The
approaching disturbance will also contribute to a strengthening 30-35
knot low level jet, which will help a stationary front along the
Texas coast lift inland and result in another round of low clouds and
possibly some drizzle along and east of Interstate 35 early Saturday
morning. This initial boundary appears to lose definition as it
lifts into Central Texas, but several convection allowing models are
indicating that the West/West Central Texas thunderstorm activity may
develop a strong enough cold pool to allow an outflow boundary to
move into the Hill Country by Saturday morning. This would serve as a
focus for continued development during the day Saturday as the main
disturbance arrives. However, the past few runs of the HRRR do not
develop an outflow boundary and keep all activity north of the
region. Given the presence of good lift across the region, steep mid-
level lapse rates, and plenty of shear, expect at least scattered
thunderstorm development to occur across the region during the day
Saturday. A lull in the activity will be possible by Saturday evening
before a secondary round develops as the main disturbance lifts
across the region. Based on the farther south trajectory, anticipate
greatest rain chances south of the Interstate 35 corridor on Sunday
morning.
Thunderstorm threats tonight and Saturday appear to range from
damaging wind, large hail, and frequent lightning. Steep lapse rates
in excess of 8 C/km will not only contribute to this hail and wind
threat, but high resolution guidance has been fairly consistent in
indicating the presence of bowing line segments (raising concerns for
the damaging wind threat). There has been an intermittent signal for
potentially discrete cells developing ahead of these bowing segments
east of Interstate 35, which may also be capable of an isolated
tornado threat. This would be heavily contingent on surface
destabilization during the day across these areas... which the
presence of low clouds/drizzle may complicate. Cannot rule out the
threat for locally heavy rain given the instability present, but
precipitable water values less than 1.5 inches and developing drought
conditions across portions of the region will help mitigate against
any widespread flood threat.
LONG TERM (Sunday through Friday)...
The disturbance begins to close off over the ArkLaTex on Sunday with
associated north/northwest flow pushing Sunday morning rain chances
off to the east by Sunday afternoon. This will help western areas dry
out and heat up into the low to mid 80s by Sunday afternoon with
slightly cooler highs in the mid 70s to low 80s across the east.
Steep lapse rates and long, skinny CAPE profiles indicating water-
loading of updrafts will contribute to a lingering damaging wind
threat across the Coastal Plains Sunday morning along with the threat
for locally heavy rain.
A few wraparound showers may be possible across portions of the
Brazos Valley/Central Texas into the Coastal Plains Sunday night into
Monday morning as the upper low ejects towards the northeast, but
dry conditions are expected through the workweek. Shortwave ridging
building in behind this system will result in temperatures rising
into the mid 80s to low 90s across the central and eastern portions
of the region mid-week with the Rio Grande possibly seeing the first
100 degree day of the year on Wednesday. A fast-moving shortwave
trough traversing the Central Plains Wednesday into early Thursday
will send a dry cold front across the state on Thursday. Somewhat
cooler high temperatures in the low 80s to low 90s are expected as
the front passes Thursday with highs finishing the work week in the
low 70s to low 80s as additional cooler air filters into the region.
&&
.PRELIMINARY POINT TEMPS/POPS...
Austin Camp Mabry 66 79 64 81 59 / 30 70 40 50 10
Austin Bergstrom Intl Airport 66 79 64 81 59 / 30 70 40 50 10
New Braunfels Muni Airport 65 80 63 82 59 / 30 60 40 60 10
Burnet Muni Airport 64 78 62 81 57 / 30 80 30 40 10
Del Rio Intl Airport 65 87 61 89 59 / 50 30 10 - -
Georgetown Muni Airport 66 78 63 80 57 / 30 80 50 50 10
Hondo Muni Airport 67 84 62 86 58 / 40 70 30 50 -
San Marcos Muni Airport 65 80 64 81 60 / 30 70 40 60 10
La Grange - Fayette Regional 69 81 66 78 60 / 20 50 50 70 10
San Antonio Intl Airport 66 81 64 82 59 / 30 70 30 50 -
Stinson Muni Airport 67 83 64 82 60 / 30 60 30 60 -
&&
.EWX WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
Aviation...Zeitler
Short-Term/Long-Term...BMW
Area Forecast Discussion
National Weather Service Grand Rapids MI
700 PM EDT Fri Apr 5 2019
LATEST UPDATE...
Aviation
.SYNOPSIS...
Issued at 320 PM EDT Fri Apr 5 2019
- Fog, locally dense, is possible overnight lasting into the
first few daylight hours of Saturday.
- The warmest weekend of 2019 so far is on tap with increasing
precipitation chances Sunday afternoon/evening. No severe
weather is expected at this time.
- An active pattern is shaping up from the middle of next week
onward, with wintry weather not out of question.
&&
.DISCUSSION...(This evening through next Friday)
Issued at 320 PM EDT Fri Apr 5 2019
Cloud cover was stubborn to go away this morning but clearing is
finally been observed across large chunks of the area, leading to
soaring temperatures into the upper 40s and lower 50s. As a high
pressure system slides over the Great Lakes tonight, fog
development (locally dense) is possible lasting through mid-
morning Saturday. We`ll let the evening crew determine whether any
fog headlines are needed as areal extent is uncertain, but the
clearing skies as of this writing suggest greater potential for
widespread fog tonight. Temperatures overnight should range from
around freezing along the US-10 corridor to around 40 near I- 94.
As upper-level ridging becomes established over the Great Lakes
on Saturday, low-level south/southwesterly flow will allow for
spring- like temperatures in the low to mid 60s area wide. Sunday
looks even warmer with highs climbing into the upper 60s, making
way for the warmest weekend of 2019 so far. Unfortunately it may
be hard to see the sun, especially Sunday, as a broad and somewhat
disorganized upper-level trough approaches from the southwest.
While dew points and PWATs are progged to climb north of 50
degrees/1" Sunday afternoon, the general disorganized nature to
the trough (muddled immensely by expected widespread convective
activity to our south) makes identifying clear sources of lift
Sunday afternoon/evening hard to discern. Maybe an MCV-like
feature originating from activity in the Plains Saturday night
will swing our way on Sunday? All the while forecast thermal and
kinematic profiles suggest little potential for anything organized
in our neck of the woods. But for now there`s still enough to
warrant increased precipitation chances, including perhaps a weak
thunderstorm or two, Sunday afternoon/evening.
Forecast deterministic guidance suggests a clipper system will
swing through the Great Lakes Tuesday dragging along a cold front,
effectively ending our warm stretch. If the front comes through
right at "peak heating" Tuesday afternoon, a band of showers or
even a weak thunderstorm is possible though the chance for severe
weather again appears pretty low. The bigger forecast concern is
the potential for a period of active weather toward the latter
portion of next week (and beyond?) as a strong 180+ kt Pacific jet
develops into deep troughing across the western U.S., placing the
Great Lakes at the end of what may end up being a fire hose of
systems. The first will take aim at the Great Lakes around the
Thursday/Friday with the 12Z suite of deterministic models sharing
remarkable (and likely coincidental) agreement in supplying a
swath of heavy snow right through central Lower Michigan. Yet the
ensemble solution spaces are still vast including solutions in
which Lower Michigan gets missed entirely, so an April snowstorm
is definitely not set in stone. Stay tuned.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 700 PM EDT Fri Apr 5 2019
It would seem there is a good chance (not 100%) that dense fog
will develop at most of the TAF sites overnight. Most of the area
had around a tenth of an inch of rain last night and with the
evaporation rate (measured by some meso-nets) around 0.05" today,
there is enough moisture remains from the precipitation last
night, assuming skies are mostly clear to develop dense fog.
Winds are light with the surface high near by. Also more moist air
is being pushed into cooler and drier air just above the surface
overnight. Model sounding from the HRRR / NAM12 show the classic
fog look with shallow saturation near the ground with temps/ dew
points increase around 3c in the first 500 ft above the ground.
The fog should lift to a low cloud deck by mid to late morning
then clear from south to north as dry air moves up from the south
as the surface high continues to move to the east.
&&
.MARINE...
Issued at 320 PM EDT Fri Apr 5 2019
Winds and waves are expected to remain relatively calm (at or below
15 kts and 3 ft, respectively) through early next week. Fog
development is possible this weekend, some of which may be dense
with westward extent.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...None.
LM...None.
&&
$$
SYNOPSIS...Borchardt
DISCUSSION...Borchardt
AVIATION...WDM
MARINE...Borchardt
Area Forecast Discussion
National Weather Service Lincoln IL
820 PM CDT Fri Apr 5 2019
.UPDATE...
Issued at 820 PM CDT Fri Apr 5 2019
Primary question will be with any kind of clearing overnight.
Latest GOES-16 nighttime microphysics combo showing the western
edge of the cloud deck from near the Quad Cities to south of
Quincy, but the clearing appears to be hitting a brick wall.
Evening sounding from our office shows the clouds to be about
2,000 feet thick, with an inversion at 850 mb at the top. RAP and
NAM try to make some slow progress with moving this cloud deck
east, but pessimism may be the way to go in this case. Have
maintained the mostly cloudy forecast overall, but showed a slight
short improvement west of the Illinois River for awhile late this
evening. Hourly temperatures needed some adjustments over the next
few hours, as they were running too warm. However, with the clouds
hanging around, a significant dropoff is not anticipated, and
went with lows fairly close to the earlier projections.
&&
.SHORT TERM...(This evening through Saturday)
ISSUED AT 345 PM CDT Fri Apr 5 2019
Broken to overcast stratus cloud deck lingered over much of IL
especially south of I-88 at mid afternoon. Abundant low level
moisture/wet ground, along with a restrengthening low level
inversion and weak wind flow will allow more lower stratus and fog
to set in especially overnight into mid morning Saturday. Lows
overnight in the mid to upper 40s in central IL, with southeast
IL near 50F. Skies to become partly sunny during Saturday
afternoon, with low clouds lingering longer in eastern IL. SE
winds increase to 8-15 mph by Saturday afternoon, with milder
highs in the upper 60s to near 70F.
.LONG TERM...(Saturday night through Friday)
ISSUED AT 345 PM CDT Fri Apr 5 2019
The 12Z forecast models continue to trend slower with arrival of
next wx system ejecting from the southern Rockies, with surface
low near the IA/MO border by dawn Sunday. Saturday evening should
continue dry, with chances of showers and isolated thunderstorms
spreading ne over CWA after midnight Sat night. Mild lows Saturday
night in the mid 50s. Good chance of showers and some
thunderstorms on Sunday and mild highs in the lower 70s with
breezy sw winds. SPC day3 outlook has slight risk of severe storms
in southeast IL later Sunday afternoon into mid Sunday evening
with marginal risk of severe as far nw as the IL river. Though
latest models are not quite as strong with the instability and
bulk shear parameters. Chance of showers and isolated
thunderstorms lingers Sunday evening, and over areas from I-55 se
overnight Sunday night.
A surface low and upper level trof over the lower MS river valley
Monday could bring chances of showers into southeast IL yet on
Monday, while thunderstorms chances mainly closer to the Ohio
river on Monday. Mild temperatures in the lower 70s for highs
Monday across CWA. Dry wx expected across area Monday night thru
Tuesday evening with slightly cooler highs in the upper 60s north
of I-72 and lower 70s again from I-72 south.
A much stronger surface low pressure system ejects from the
central Rockies into KS during Wed with a warm front extending
eastward over the mid MS river valley. Increasing chances of rain
showers mainly along and north of I-72 overnight Tue night into
Wed. More of a north to south temp gradient on Wed with highs mid
to upper 50s northern CWA and upper 60s to near 70F in southeast
IL. 993 mb surface low pressure tracks into St Louis area by
midnight Wed night and travels near I-70 into west central IN by
dawn Thu. Good chance of showers and some thunderstorms over area
Wed night and lingering chances of showers Thu. Stronger winds on
Thu with cooler temps, highs Thu range from low to mid 50s
northern CWA and low to mid 60s in southeast IL. Some light rain
showers linger Thu night and could mix with light snow showers
overnight Thu night into Fri morning. Highs Fri in the upper 40s
and lower 50s, mildest in southeast IL. Lows by next Friday night
to reach lower 30s over much of area especially from I-70 north.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 631 PM CDT Fri Apr 5 2019
Challenging forecast for this TAF set. Fairly widespread MVFR
cloud deck exists across central Illinois at 23Z, with ceilings
about to lower near the Indiana border. Some clearing is edging
into extreme western Illinois, but there is some question on how
much this is going to progress eastward. Any clearing would likely
result in a quick formation of very low clouds and fog. Went the
pessimistic route for now, and kept MVFR going until about 09Z,
with a few hours of IFR. Clouds may struggle again to scatter out
on Saturday, but will show some improvement by 18Z.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...Geelhart
SHORT TERM...07
LONG TERM...07
AVIATION...Geelhart
Area Forecast Discussion
National Weather Service Lubbock TX
652 PM CDT Fri Apr 5 2019
.AVIATION...
Scattered TSRA just SW-W of LBB will continue developing and
moving north through early evening, before a more considerable
round of TS arrives in the 9-11 PM time frame. Some TS will be
severe with downbursts and hail. After TS affects all terminals
tonight, MVFR to perhaps IFR ceilings are likely at all sites
before drier SW winds overspread the Caprock toward midday. At
CDS, there is a slim chance for additional TS tomorrow afternoon
near a dryline, but prospects for this are too low at this time.
&&
.PREV DISCUSSION... /issued 243 PM CDT Fri Apr 5 2019/
DISCUSSION...
The main weather impacts will be the potential for severe
thunderstorms this evening into overnight and strong winds on
Wednesday. The shortwave trough responsible for tonight`s weather is
currently over northwestern Mexico and will quickly move east. Ahead
of this trough cloud coverage has increased and southerly winds are
brining up dewpoints in the mid 40s to mid 50s this afternoon. By
this evening upper level flow is very divergent and 850mb winds will
increase around 00Z with surface convergence over the South Plains.
Hi-res models have backed off some on early showers but have two
main rounds later. Both the HRRR and RAP have storms initiating
southwest of Lubbock around 00-01Z then moving northeast in a bowing
line. Then another round starts around 08Z further south and moves
northeast. With good instability and minimal CIN, expect storms to
become strong with hail up to 2 inches and winds to 70 mph possible.
As 850mb winds increase after 00Z, shear also increases with longer
and more curved hodographs so tornadoes will also be a possibility.
Storms will continue through the night and may not clear the eastern
counties until after 10-11Z. Have also increased PoPs in the Rolling
Plains Saturday morning to account for any lingering rain.
The upper level trough will continue to move east through the
weekend. A weak cold front will move through on Sunday morning
dropping highs a few degrees. Upper level ridging will build early
next week leading to above normal temperatures and highs will reach
the upper 80s to low 90s by Tuesday. As the next trough approaches
on Wednesday the pressure gradient will tighten significantly
resulting in a windy day. Have gone on the higher end of guidance
with winds 25-30 kts but did not go as highs as the MOS guidance of
45kts. Depending on how much rain we get tonight, above normal temps
and high winds may lead to fire weather concerns on Wednesday.
&&
.LUB WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
93
Area Forecast Discussion
National Weather Service Blacksburg VA
1011 PM EDT Fri Apr 5 2019
.SYNOPSIS...
Low pressure over the Mississippi Valley will move east and
offshore by Saturday followed by weak high pressure. A complex low
pressure system over the Plains Saturday will track into New England
and will push a cold front across the Mid Atlantic region on
Tuesday. Yet another low pressure system moves from the central
United States into the east by the end of the week.
&&
.NEAR TERM /THROUGH SATURDAY/...
As of 1011 PM EDT Friday...
No major changes to the going forecast at this point and have
only accounted for current observations into the going forecast
with this update.
In-situ wedge has built southward into the Carolinas leading to
lots of overcast skies and reflected in the GOESEast Nighttime
Microphysics RGB composite imagery. Wedge will remain with us
through the remainder of the overnight, though some erosion of
overcast cloud cover is anticipated toward the pre-dawn hours
across the Mountain Empire. Periods of mist or light ground fog
to this point haven`t been as prevalent in the presence of
modest northeast/east surface winds. However winds are expected
to lighten some and this may increase coverage of foggy areas
into the overnight as temperature/dewpoint spreads are quite
narrow. Don`t think we`ll see dense fog from this but based on
recent HRRR and NBM visibility guidance, the potential for SPS-
worthy fog mention isn`t out of the question, especially in the
New River Valley area and adjacent portions of I-81. No changes
to low temperatures which will only fall a few degrees given
prevalence of cloud cover and limited to weak warm low-level thermal
advection.
As of 145 PM EDT Friday...
Rainfall winding down from east to west across the CWA early
this afternoon, with a few lingering showers across the piedmont
over the next few hours before ending completely. Rainfall
totals up to 18z (2 PM) generally in the 0.25 to 0.75 inch
range with some higher amounts approaching 1.00 inch or more
over parts of SW VA. Both Dual-Pol and Legacy radar estimates
are higher over parts of New River Valley with 2+ inches in some
areas but not corroborated by any rain gages and possibly due to
bright-band effects. Either way, no hydrologic impact other
than mostly welcome rain. Skies will remain cloudy this
afternoon and evening for the most part with patchy drizzle
early and some fog possible overnight and temps holding mainly
in the 40s. Some in-situ wedging will remain into Saturday
morning as the weak surface low off the NC coast slowly drifts
eastward into the western Atlantic which may delay clearing
until late morning or even early afternoon depending on how
strong it is. As a more zonal westerly flow takes over will see
generally clearing skies later in the day with a noticeable
warmup by mid- to late afternoon, some 15-20F higher than today.
&&
.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY NIGHT/...
As of 230 PM EST Friday...
Saturday night into Sunday an upper level shortwave ridge will build
over the area. Closer to the surface, southerly flow will start to
increase on the west side of a ridge of high pressure that will be
situated along the east coast of the U.S. and on the east side
of an upper level shortwave trough across the center of the
country. The result will be the advection of the low level
moisture into the area that will bank-up against the higher
terrain along the crest of the Blue Ridge. Look for some patchy
light rain in this area Saturday night. On Sunday, a warm front
will cross the area early on Sunday and be situated north of the
area by Sunday night. As Sunday progresses, the lower
atmosphere will become slightly unstable in the west, and allow
for the potential for some isolated to scattered showers and
storms.
Sunday night into Monday night, the central U.S. upper low/trough
will make slow progression towards the area. This will keep showers
in the forecast during the period with isolated to scattered
thunderstorm Monday from mid-day through the early evening. Some
locally heavy rain is possible during this time period.
Temperatures will trend milder during this portion of the forecast.
By Monday into Monday night temperatures will average around ten
degrees above normal.
Forecast confidence during this portion of the forecast is moderate
to high.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
As of 1230 PM EST Friday...
On Tuesday, a closed upper low will be poised to head eastward from
over the Tennessee Valley to the coast of the Carolinas, thus
bringing its associated cold front into and through our region. In
advance of this system a generous fetch of Gulf of Mexico moisture
will be advecting into the area on increase 850 mb winds. While
showers look very probable across the area, isolated thunderstorms
also cannot be ruled out. Forecast afternoon surface based CAPE
values are expected to be in neighborhood of 1000 - 2000 J/Kg just
as the associated front is crossing the area.
High pressure is expected to build into the area in the wake of the
Tuesday-system. This is expected to bring dry weather to the area
for the latter half of Tuesday night, Wednesday, Wednesday night,
and Thursday morning. Tuesday evening parts of the area still may
have some lingering showers associated with the departing cold
front, especially the southeastern sections of the forecast area.
Thursday afternoon through Friday model guidance becomes a bit more
variable in terms of timing and positioning of the main synoptic
features. What is consistent among the solutions is a trend for the
center of the next upper level trough/low to remain close to the
U.S./Canadian border. The biggest question is not whether it will
have an associated cold front or not, or if it will cross our area,
but more of timing of this feature and sensible weather influence on
our area. A consensus forecast offers late Thursday night into early
Friday as the time frame with isolated to scattered coverage of
showers, especially across western and northern sections of the
forecast area.
Temperatures during the Tuesday through Thursday portion of the
forecast are expected to be around ten to fifteen degrees above
normal. By Friday, readings will be closer to normal, or about five
degrees above normal.
Forecast confidence during the Tuesday through Thursday timeframe is
moderate with low to moderate confidence on Friday.
&&
.AVIATION /02Z SATURDAY THROUGH WEDNESDAY/...
As of 731 PM EDT Friday...
Low clouds will linger tonight into Saturday morning with areas
of fog and patchy drizzle or light rain. Widespread IFR/LIFR
will continue tonight into Saturday. Gradually improving flight
conditions on Saturday as the weak low off the coast departs
and weak cool air wedge dissipates. Winds will remain light
tonight into Saturday. Be prepared for mountain obscurations
overnight with the low clouds.
Medium confidence in ceilings,visibilities and winds during the
taf period.
EXTENDED AVIATION DISCUSSION...
MVFR/IFR conditions are possible with scattered showers and
isolated thunderstorms Sunday through Tuesday. Drier weather is
expected Wednesday into Wednesday night.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...None.
NC...None.
WV...None.
&&
$$
SYNOPSIS...AMS
NEAR TERM...AL/KK/PC
SHORT TERM...DS
LONG TERM...DS
AVIATION...KK/PC
...Update to aviation forecast discussion...
.SHORT TERM...(This evening through Saturday)
Issued at 338 PM CDT Fri Apr 5 2019
20Z water vapor imagery shows an upper trough over the
southwestern U.S. with a shortwave over the Pacific Northwest
lifting into British Columbia. At the surface, an area of low
pressure was slowly deepening along the lee of the central
Rockies. This has kept a southerly wind over the forecast area
with dewpoints steadily rising into the lower 50s.
For tonight the main question is whether there will be any showers
ahead of the main upper trough. Various solutions develop some light
QPF across north central KS. But a closer look at the forecast
soundings shows some mid level dry air that would need to be
overcome. With the general consensus among models for the main surge
of moisture to occur Saturday afternoon, think chances for
measurable precip are only around 10 percent across north central KS
tonight. SO will maintain a dry forecast. Stronger mixing tonight is
expected to preclude any fog formation. Although the NAM insists on
some saturation in the boundary layer. If the NAM proves correct,
think there may be some stratus develop. But with the GFS and RAP
having a hard time saturating the boundary layer, do not have much
confidence in the NAM solution and think mid and high clouds will be
predominate.
For Saturday, precip chances should be on the increase through the
afternoon and into the evening. Confidence in widespread
precipitation is waning as models have trended towards a ill-defined
wave lifting across the area. Nevertheless there should be plenty of
moisture ahead of the wave with some modest instability of around
1000 J/kg so have kept POPs in the likely category. Risk for severe
storms appears to be pretty conditional as lapse rates and deep
layer shear are fairly marginal. Hodographs show weaker mid level
winds cause an inflection in the hodograph implying storms may have a
difficult time remaining discrete. So while an isolated storm with
hail can`t be ruled out, the environment doesn`t look favorable for
a lot of severe weather.
.LONG TERM...(Saturday night through Friday)
Issued at 338 PM CDT Fri Apr 5 2019
Showers and storms are expected to lift out of the area late
Saturday night with the upper trough axis moving into IA. There
could be some redevelopment on Sunday as a weak frontal boundary
moves through the area. Again there could be some modest
instability out ahead of the boundary. But dynamics look to be
disorganized with possibly some frontogenesis along the boundary
being the main driver of redevelopment. There is not a lot of cold
air progged to move in behind the boundary, so highs on Sunday
have trended warmer.
Much if not all of the forcing for vertical motion looks to be east
of the area by Sunday evening. So the forecast is for dry weather
Sunday night through Tuesday night before the next upper trough
moves into the plains. Have trended temps warmer for Monday with
models showing good low level warm air advection and a downslope
component to the surface wind. A weak backdoor front may still try
to move into the forecast area on Tuesday. Still looks like highs
could reach the 70s. But this will be dependent on how strong the
boundary turns out to be.
There is still a fair amount of spread in the models with the system
for Wednesday and Thursday. Because of this have stayed pretty close
the the consensus blend. In general there appears to be a trend for
a more southern track to the low pressure system. This could allow
from some snow to mix in with the rain across northern KS Thursday
morning. But models tend to show the heavier QPF lifting out of the
area as temps fall into the 30s. Have trended temps cooler for
Thursday and Friday as the ECMWF and GFS develop some reasonable
cold air advection behind the system. With that lows are forecast to
be in the 30s with highs in the 50s.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 636 PM CDT Fri Apr 5 2019
Expect VFR conditions for the next 24 hours. Most numerical models
keep visibilities above 7 miles through the early morning hours of
Saturday. The NAM and WRF-ARW did show patchy fog developing at
the KTOP and KFOE terminals, though my thoughts are that the
nocturnal boundary layer may not decouple fully due to a low-
level jet increasing to 35-40 KTS at 1200 feet above the surface
after 6Z SAT. There will be 30-35 KTS of low-level wind shear from
the surface to 1500 feet at the terminals from 6Z SAT-14Z SAT.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...Wolters
LONG TERM...Wolters
AVIATION...Gargan