June 2020

[Cromagnum]

NWS backed rain chances down to 20% for me today and this weekend. Up to 50% on Monday though so ill compromise for a sunny weekend if the weather gods can make it up during the work week.

[Texaspirate11]

I guess it's a race to see what gets here first Sal or the rain maker

[Cpv17]

There’s a big difference between the GFS and the Euro/CMC. Euro and CMC see the same thing pretty much. The GFS isn’t picking up on this at all.

[srainhoutx]

I see you folks have been experiencing some typical SE Texas June weather. It's been wet and chilly across the Smokey Mountains for the past couple of weeks. Daytime highs here have been in the low 60's this week and night time lows in the low to mid 50's.

Looks like a pattern change is coming for the the Region. Fingers crossed you folks get some beneficial and cooling rains.

Friday morning weather briefing from Jeff:

Dry and hot high pressure that has been over the region for the last 2 weeks will transition into a cooler and wetter late June pattern.

High pressure will begin to shift eastward today allowing a better fetch of tropical moisture to arrive into areas west of I-45 from the southern Gulf of Mexico. This is already noted with ongoing streamer activity on radar around Matagorda Bay. With heating this morning scattered storms will develop from the TX coastal bend to roughly Wharton County and expand NW/NNW across our western counties through the afternoon hours. Areas east of a line from College Station to Katy to Galveston will see lower rain chances as moisture levels are lower and this area is still under more high pressure influence.

High pressure builds east on Saturday and another surge of tropical moisture is poised to move into SE TX from the south. As southerly winds increase this moisture plume will be pulled into the TX coast and expect scattered storms to form along the inland moving seabreeze front and expand across much of the area on Saturday.

Sunday and Monday look favorably active with weak large scale lift in place from a sub-tropical jet overhead and continue influx of Gulf moisture with onshore flow. Scattered to numerous storms are expected and storm motions look to start to slow so heavy rainfall in a short period of time will become increasingly likely. Given dry grounds of late, most of the rainfall will be beneficial, but could see some street flooding issues if short duration rates become excessive.

Mid week forecast has become more challenging as recent guidance being led heavily by the ECWMF is showing an upper low shear axis over the region becoming a cut-off mid and upper level low near the TX coastal bend. This results in significant upward motion near the coast and over the Gulf waters Wednesday and Thursday and is suggesting a heavy rainfall signal. The GFS is much drier and for now given the uncertainty, will just keep scattered daily rain chances Tuesday-Friday but these could be significantly altered if the pattern continues to trend toward the ECWMF

[Cromagnum]

Lots of popcorn but it missed my house on all sides, even dissipating and reforming just pass us. Such garbage.

[don]

12z Euro shows a "No name"storm, in what would be the equivalent of a tropical depression, the system never closes off so it wouldn't technically be a tropical cyclone but the affects would be virtually the same.With waves of very heavy rain moving into the area.FWIW

[unome]

the storm on the east side dropped a fair amount of rain, kind of sitting in one spot

https://www.harriscountyfws.org/GageDet ... l&selIdx=1

https://mrms.nssl.noaa.gov/qvs/product_ ... s_step=120

[DoctorMu]

There’s a big difference between the GFS and the Euro/CMC. Euro and CMC see the same thing pretty much. The GFS isn’t picking up on this at all.

GFS has a front instead extending into SE TX.

Ensembles are just seeing lemonade.

[DoctorMu]

12z Euro shows a "No name"storm, in what would be the equivalent of a tropical depression, the system never closes off so it wouldn't technically be a tropical cyclone but the affects would be virtually the same.With waves of very heavy rain moving into the area.FWIW

Pretty much the way HGX sees it.


Area Forecast Discussion
National Weather Service Houston/Galveston TX
352 PM CDT Fri Jun 19 2020

.SHORT TERM... (Tonight through Saturday Night)

Showers and thunderstorms are expected to wane near sunset with
the loss of daytime heating. Skies are also expected to clear by
mid evening with some low clouds redeveloping late tonight over
the far western zones. PW values today were considerably higher
than progged yesterday so am a little nervous with how models are
handling PW values but there is a growing consensus that PW values
will reach 2.00 inches on Saturday. A weak short wave embedded in
the 500 mb flow will approach in the afternoon with convective
temps in the upper 80`s. Showers and thunderstorms should become
more widespread on Saturday and a slow storm motion supports brief
but locally heavy rain with the stronger storms. Will maintain
rain chances into the evening until a bit of subsidence develops
in the wake of the departing short wave. Skies will clear by mid
evening with showers possible near the coast by early Sunday
morning. 43

&&

LONG TERM [Sunday through Friday]...

The long-term forecast period continues to be defined by increasing
low-level moisture through the end of the weekend and into the
middle part of next week. As moderate onshore flow remains expected
to persist, global models continue to show a widespread swath of
PWAT values of around 2 inches across SE Texas by Sunday night. With
forecast soundings showing convective temperatures in the low 90s,
MUCAPE values in excess of 2500 J/kg, and ample low-level moisture,
Sunday and Monday will prove favorable for the development of
showers and thunderstorms as an upper trough axis moves through the
area. Have continued to maintain PoPs of 40-50% as agreement across
model solutions remains good for this period.

Global models start to diverge as we head into the middle of next
week. Over the past several model runs, the ECMWF solution has
developed a cutoff low over the western Gulf by Tuesday night, with
an associated weak coastal low developing to our southwest by
Wednesday morning. PWAT values surge further above 2 in during this
time, and widespread precipitation develops across the region
through Friday as the surface feature pushes further northward. GFS
solution, on the other hand, does not develop this feature and as a
result things remain drier. Canadian has trended towards the
European solution, although has remained less aggressive in terms of
rainfall totals. Have kept PoPs in the vicinity of 40% due to the
current disagreement amongst model sources, however the Wednesday-
Thursday period will need to be monitored closely for the
possibility of heavy rainfall.

Seasonable summertime highs continue through the week with
temperatures reaching the mid 90s in most locations. However, with
the increase in dew points as low-level moisture supply strengthens,
heat index values will rise into the triple digits and heat safety
precautions should be taken.

Cady

MARINE...

High pressure east of the area and low pressure over southern New
Mexico will maintain an onshore flow through the weekend. he
gradient will briefly tighten tonight and will issue a SCEC for
the increase in winds. Winds will drop off tomorrow as the
surface high moves east and the gradient relaxes. The diurnally
driven pattern of weaker daytime winds and stronger night winds
will persist through Monday night. Onshore winds will persist into
the middle of next week. A developing upper level trough over the
Texas coast early next week will allow for scattered showers and
thunderstorms over the Gulf next week. 43

&&

.PRELIMINARY POINT TEMPS/POPS...
College Station (CLL) 93 73 92 74 93 / 30 20 30 20 30
Houston (IAH) 92 75 91 76 92 / 30 10 50 20 40
Galveston (GLS) 88 80 89 81 89 / 30 10 20 20 30

[DoctorMu]

Canadian and GFS have 1-2 in of rain for much of the area in the next 10 days.

Euro's subscribing still to a tropical wash.

[DoctorMu]

re: Rainfall. Rich moisure and instability will combine today for a good chance of thunderstorms.

High energy CAPE Sunday. Expected seabreeze Monday and Tuesday. However, Wednesday and Thursday look like the greatest chance for precip as a front and approaching cold front create moisture and lift.

However, on Friday Saharan dust arrives at the midlevels and another Big Suck begins.


Area Forecast Discussion
National Weather Service Houston/Galveston TX
708 AM CDT Sat Jun 20 2020

.AVIATION [12Z TAF Issuance]...

Intermittent IFR and MVFR conditions throughout the forecast area.
Widespread showers and thunderstorms will bring some gusty winds and
low ceilings to the CLL/UTS/CXO flying areas through the morning
hours. IAH/HOU has showers and thunderstorms in the vicinity this
morning but should pass by around 14z. SGR/LBX will have showers and
thunderstorms in the area throughout the day and GLS having mainly
showers with higher indications of afternoon thunderstorms.

With the interaction of a shortwave, diurnal effects, and outflows
from a semi organized system to the north that is moving into the
area, instability will be on the rise throughout the day. Showers
and thunderstorms will be possible throughout the day in all
locations which could bring lowered ceilings/visibility and gusty
winds.

Tonight, MVFR ceilings as low as 1200FT AGL will be effecting the
northern flying areas effecting CLL/UTS/CXO areas but could reach
the IAH/SGR regions as well. 35

&&

.PREV DISCUSSION /Issued 509 AM CDT Sat Jun 20 2020/...





.SHORT TERM [Today Through Sunday]...

An upper level weak shortwave was able to scoot into our local area
yesterday. Early this morning, the shortwave will be on its way east
into the MS/AL area and a somewhat zonal flow pattern will develop
aloft, although small upper level weaknesses look to move across the
region throughout the day as an upper level trough moving east over
the Great Plains continues into the western Great Lakes region.
Regardless of the shortwave displaced to our east, weakness will
remain along the mid levels over the region today. Along the SFC,
southerly wind flow will continue filter rich low level moisture
from the Gulf into Southeast TX resulting in a widespread range of
PWs of up to around 2.0 inches. Instability will be on the rise with
SB and MU CAPE values reaching 3000 J/kg by late morning and
continuing into the afternoon. Forecast soundings also show a bit
more moisture along the BL to 600MB levels than yesterday. Moreover,
outflow boundaries from the thunderstorms to our north will also be
moving southward into the CWA this morning, which depending on how
far south the boundary moves, may help trigger more activity and/or
enhance ongoing convection. Thus, expect a bit more shower and
thunderstorm activity today across much of the CWA. Activity will
dissipate late evening and early tonight as diurnal heating
decreases and low level moisture somewhat ebbs overnight through
Sunday morning. A few passing isolated showers from the Gulf waters,
however, will remain possible overnight into early Sunday morning.

Another somewhat stronger shortwave trailing behind the main upper
level trough axis will make its way across Southeast TX Sunday
afternoon and remain in place through early next week. Global models
actually want to develop an upper level closed low sometime after
Sunday night. Moreover, based on the current forecast soundings,
environmental conditions may end up a little more unstable than
today. Thus, it is likely that we will continue to see periods of
showers and thunderstorms throughout the day Sunday - possibly a bit
more convective than today. 24


.LONG TERM [Sunday Night Through Saturday]...
Sunday afternoons big CAPE thunderstorms should wane during the
evening hours then expect redevelopment after midnight as left
front quad of the subtropical jet curves in across the region
likely focusing scattered to possibly numerous showers over the
coastal waters spreading into the southern areas. By sunrise
Monday will have a shear axis overhead with an upper low taking
shape over S TX and this set of features should help to plague
SETX with showers and thunderstorms this workweek. Slow moving
storms should be the norm Monday - initially near the coast in the
morning shifting inland through the day and probably a short lull
in the evening before showers start up again over the coastal
waters early Tuesday morning. The upper low sags even further
south-southwest Tuesday and cold front dips down into Oklahoma
placing SETX in between these features with easily reachable
convective temperatures-PW of 1.5" increasing to 1.8-1.9"
throughout the afternoon. Moisture gradient indicative of
scattered to numerous showers and thunderstorms in the central and
eastern areas and a little less coverage over the west. Much
richer tropical moisture should start to surge north early
Wednesday as the cold front sags further south and possibly even
reaching the northern counties. This abundant moisture flowing
north impinging on the boundary should help to fuel storms and
some will no doubt push off the boundary and sag southward further
into SETX. At this point Wednesday is looking like a stormy day
across the region and has some potential for heavy rain in excess
of 3-5 inches. Rinse and repeat on Thursday though the front
should be weak and likely lifting northward but low level flow
strengthens (PW of 2.2-2.4")and that will increase the threat of
heavy rain. Thursday night through Friday the upper low should be
filling as it lifts NNE through SETX/Hill country. Diurnal
convection pattern should be enhanced Friday and expect an active
seabreeze again with a heavy rain threat.

Change looks to occur late Friday into Saturday with drier air
eventually pushing into the region from the southeast - likely the
leading edge of the Saharan dust cloud.
45


.MARINE...

Winds will relax a bit early this morning to slightly below SCEC
criteria. A diurnal wind pattern will continue across the waters
during the next several days. Onshore winds will slightly increase
overnight, possibly reaching SCEC conditions for a few hours, and
relax a bit during the day. Chance of showers and thunderstorms
increase next week as tropical moisture transport from the Gulf
continues and an upper level trough develops over the Texas coast.
Seas of 2 to 4 feet expected across the Gulf waters throughout the
forecast period, however, strong gusty winds and slightly higher
seas could accompany strong thunderstorms. 24


.TROPICAL...
Area well off of South Carolina coast has a slim chance of
hybrid/subtropical development Sunday though probably only
briefly as it lifts out.

Impressive blob of deep convection with an upper low near 30n/50w
that should be slowly shifting eastward and getting further
removed from richer moisture and over into cooler waters.

The large Saharan dust cloud over the central Atlantic MDR continues
to spread westward and may spread into SETX late Friday or Saturday
next week.

45

&&

.PRELIMINARY POINT TEMPS/POPS...

College Station (CLL) 94 75 94 76 93 / 60 20 30 20 50
Houston (IAH) 92 76 92 77 91 / 50 20 50 10 60
Galveston (GLS) 91 81 91 81 87 / 40 20 30 20 60

[Cromagnum]

Was fishing at surfside and saw the fireworks to the north. Glad to see my house picked up an inch.

[Katdaddy]

So far .56" in W League City and the yard greatly approves. Back home from NTX and I can feel the humidity this afternoon.

[DoctorMu]

Surprise rain - line from N. Texas this morning.

Only 1.03 inches for the month so far, though.

[DoctorMu]

Mega juicy air out there.

[Cpv17]

Well it looks like the Euro and GFS kinda came to meet in the middle which is what happens a lot. The Euro is no longer showing any crazy rainfall totals.

[Cromagnum]

Another couple of heavy rounds already this morning

[DoctorMu]

Streamer showers around. Need another taste of rain in B/CS.

Per CPV, Euro has backed down on rainfall prediction. Still Hoping for 1-2 inches this week.

[don]

Looks like this week is going to be pretty busy with multiple days of locally heavy rain and street flooding potentially. The good news is that a widespread flooding threat seems less likely now. But some places locally could get a decent amount of rain before its all said and done. Due to high precipitable waters and a stalled out front. I expect widespread rainfall amounts of 1-3 inches will be common by the end of the week, but i wouldn't be surprised to see some localized areas picking up 6+ inches of rain.

[Cpv17]

Rain chances seem to be getting lower and lower each day for this week. Shouldn’t be surprised though because that’s how 2020 has been. Looks good in the medium/long range only to go somewhat poof the closer it gets. Be lucky to get an inch this week. The GFS was right the whole time. The Euro lost this battle.