djmike wrote: ↑Wed Jun 24, 2020 9:05 am
Ok. I thought this was supposed to be waaay more eventful than what it was? What happened?
IMO, the explosive development out over the Gulf yesterday morning limited moisture influx throughout the day. Dew Point's weren't as high as the day before and actually stabilized and dropped a couple degrees later in the afternoon. Actually felt quite nice outside yesterday evening. Models didn't really handle the initiation of that Gulf blob well. From what other meso models seemed to indicate was there would be a seabreeze colliding with the leftover outflow boundary from the storms out over Central TX yesterday and both of those would have likely met up somewhere in our region. Those two forcing mechanisms would have likely developed some strong storms as they very slowly propagated southward with the mid-level/surface low aiding in redevelopment behind it (like a pinwheel). Certainly glad we didn't have a flood like the NAM, Euro, WRF were indicating. While no certain model would be considered a win in this event, the HRRR overall did a decent job, especially after the 12z run yesterday as the 18z and 00z NAM was still indicating a deluge over the area.
The low looks to squeeze and wash out over the area this evening and a leftover boundary will likely setup near the coastal areas bringing a focus of redevelopment of isolated to scattered storms today and tomorrow before we dry back out a bit as we expect the SAL to make its debut this season.
Just seems like any time flooding is advertised and all over social media, it never verifies. Its the pop up unexpected storms that dump 7-10” of flooding rains. Here in Beaumont, Sunday NWS showed 80% heavy storms for Monday, Tuesday, Wednesday and Thursday. We had more rain on Monday then this whole week. Tuesday we had nothing. Today, the day of the big possible flooding, we get rain showers no different than a regular 40% chance day. Its getting to the point where if flooding and lots of rain being advertised all over social media, its not gonna happen. So far, my belief still holds.
djmike wrote: ↑Wed Jun 24, 2020 10:13 am
Just seems like any time flooding is advertised and all over social media, it never verifies. Its the pop up unexpected storms that dump 7-10” of flooding rains. Here in Beaumont, Sunday NWS showed 80% heavy storms for Monday, Tuesday, Wednesday and Thursday. We had more rain on Monday then this whole week. Tuesday we had nothing. Today, the day of the big possible flooding, we get rain showers no different than a regular 40% chance day. Its getting to the point where if flooding and lots of rain being advertised all over social media, its not gonna happen. So far, my belief still holds.
These meso scale features are often difficult to forecast. Look back a few weeks ago with the large upper-level low parked over the state meandering around sending leftover boundaries all over the place. NWS can forecast percentages all the want as they see fit, but if you want a better insight read their discussions as they'll often mention even when they are uncertain with how things will play out, especially with these types of setups and how one small change can throw a wrench in the whole forecast.
For example, here is an update from 1:07p yesterday from HGX regarding the uncertainty of development because of the thunderstorms out over the Gulf:
Area Forecast Discussion
National Weather Service Houston/Galveston TX
107 PM CDT Tue Jun 23 2020
.UPDATE...
Did make some changes with the short-term grids with respect to
POPs/WX given the current trends where activity along the coast
continues to strengthen and increase in coverage. At this time,
not exactly sure how this will affect the potential for shower/
thunderstorm development later this afternoon over our northern
counties. SREF models have not been great with trends this mor-
ning and afternoon so far...but a lot of the guidance are still
pinging on the potential for widespread rains tonight/early to-
morrow. Did go ahead and issue a Flash Flood Watch starting 7PM
this evening through 7AM tomorrow morning. Stay tuned. 41/11
Had a gut feeling that Gulf blob was going to be a bit of a speed bump for the inflow for the overnight rains. Still got a solid, and highly efficient rain out of it though. Had that 'Harvey' sound to it, just a roaring rain. It's a bit of a catch 22; you'd rather over-forecast a possibility of flooding and not verify, but still get something out of it vs. the opposite.
Low seems to be holding firm just east of B/CS, I'd peg sitting right over Roans Prairie/Anderson. NWS still has decent high rain chances through early next week, but I'm hesitant to jump on board with that. I'll take any drop that falls though!
Area Forecast Discussion
National Weather Service Houston/Galveston TX
105 PM CDT Wed Jun 24 2020
.AVIATION...
Periods of showers with the chance for late afternoon thunderstorms.
Ceilings are lifting to either high end MVFR to VFR this hour.
VFR cats should continue through the remainder of the afternoon
with occasional lowering to MVFR within more moderate rainfall.
regional decks are forecast to lower back into MVFR through the
evening hours. The greatest chance for shower and thunderstorm
redevelopment will be during the overnight early Thursday morning
hours and will likely be focused across more southern terminals
(HOU southward). Ceilings will primarily remain MVFR but there
could be a period of IFR over the northern, more rural air fields.
South to southwest winds will remain up at GLS through the early
Thursday hours. 31
&&
.PREV DISCUSSION... /ISSUED 1049 AM CDT Wed Jun 24 2020/
UPDATE...
The upper low circulating over eastern Texas will slowly open up
into a longwave trough as it moves eastward into the Sabine River
Valley late tonight. In the meantime, expect scattered showers
with the lone rumble of thunder as the low churns across our CWA
this afternoon. Slightly drier western air rotating around the
backside of the low may scatter out more western county afternoon
clouds. Peaks of sun will aid in these counties warming into the
lower to middle 80s. Simply the presence of the upper low will
provide enough regional instability (with near 80 F convective
temperatures) to keep high end PoPs in today for return shower
and thunderstorm activity. Short range high resolution modeling
still wants to redevelop a southern band of convection closer to
the coast, or generally south of I-10, during the overnight early
Thursday morning hours. 31
It’s disgusting outside. Muggy as heck!! And not much of a breeze here either. Models are still calling for some pretty good rains over the area the next couple days!
Area Forecast Discussion
National Weather Service Houston/Galveston TX
354 PM CDT Wed Jun 24 2020
.SHORT TERM [Tonight through Thursday]...
The middle to upper level low that is slowly rotating across the
region will keep moderate to high rain chances in place through this
period. While there is enough instability to initiate isolated
thunderstorms, most of the precipitation will be light and in the
form of showers through the early Thursday morning hours. A distinct
deformation zone extending from a weak near stationary coastal
surface boundary up into the middle levels will be the focus needed
to allow for the redevelopment of (overnight) early Thursday morning
convection. Overnight conditions will be warm and humid with
scattered showers forming over the southern two thirds of the
forecast area. Minimum temperatures will be within a degree or two
of lower to middle 70 dew points.
The short range and global model solutions are generally showing a
consolidation of precipitation along or near the coast/points
offshore from after midnight tonight through the sunrise hour. As of
now, prepare for another band to form somewhere near the city
southward and impact more southern communities from before sunrise
through the late morning hours. QPF will range from a few tenths of
an inch to locally 1-2 inches over areas where the banding either
trains of simply slows to a crawl on its southeastern exit. Most of
the action should wane before lunch with scatted shower/isolated
storm activity as this weak coastal synoptic scale boundary lifts
northward as a warm front with the help of daytime heating. Late
morning into early afternoon clearing skies may also allow for the
development of a late afternoon sea breeze that could interact with
old convective outflow or the warm front. With less anticipated
afternoon rainfall and partially clear skies...tomorrow is forecast
to be a few degrees warmer than today; average middle 80s. 31
&&
.LONG TERM [Tomorrow Night through Wednesday]...
Elevated rain chances will continue for SE TX through the end of
the week and possibly through most of the upcoming weekend. With
the upper low lingering over the state and a steady influx of 2"
PWs from the Gulf, daytime heating will help with development on
the various boundaries across the CWA on Fri. As the low weakens
further, this general pattern of mainly diurnal activity will be
continuing into Sat/Sun but with slightly less coverage each day.
Upper level ridging will be trying to build over the area by the
start of next week...and this should translate to lower POPs and
higher daytime temperatures. 41
&&
.MARINE...
Winds/seas have decreased across the marine waters this afternoon
and should continue this trend tonight as the shower/thunderstorm
coverage decreases tonight. However, we could see more periods of
unsettled weather through the next few days as an upper level low
pressure system lingers over the state. This pattern will also be
helpful in producing periods of more elevated winds/seas and SCEC
flags will likely be needed on occasion. Otherwise, things should
be settling down by the end of the weekend (i.e. these storms) as
high pressure tries to build in over the region. Generally light/
moderate onshore winds to prevail. 41
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...SMALL CRAFT SHOULD EXERCISE CAUTION until 4 PM CDT this
afternoon for the following zones: Coastal waters from
Freeport to Matagorda Ship Channel TX out 20 NM...Coastal
waters from High Island to Freeport TX out 20 NM...Waters
from Freeport to Matagorda Ship Channel TX from 20 to 60
NM...Waters from High Island to Freeport TX from 20 to 60
NM.
Yeah the HRRR has done a good job showing the boundary location and rain set up most of the day. Looks like it was spot on looking at radar and where the stalled boundary is.
Beginning to hear some thunder out there. Radar is beginning to go off pretty good. Looks like the boundary is stalled out just to my NW by maybe 10-15 miles.
Incredible rainfall rates overnight and this morning in western Harris county and into Fort Bend Co. Nearing 8 inches of rain as a stationary boundary has just parked over the area and low level jet feeding into this band of rain. Flash Flood Watch till 10am with a few Flash Flood Warnings.
South Mayde at Greenhouse Rd bayou is over its banks.