Saturday, December 12, 2015, DFW Airport recorded its hottest all time low temperature for the month of December. The low was 70°F. The previous record was 69°F set on December 16, 1924. This marks the first time, since weather records have been kept, that the mercury failed to drop below 70°F in a 24-hour period during the month of December.
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RAINFALL RECEIVED ACROSS THE AREA
Below is a snapshot of rain totals received since our rain event began yesterday, December 12, 2015. Overall forecast values were a little bit lower than forecasted for the central portions of the Metroplex. Western sections did well by staying at an inch or less. Eastern sections stayed between 1 and 2 inches, and the much heavier rains were east of the forecast area as predicted. Of note, Gainesville, TX has hit a whopping 80 inches of rain for 2015 – truly incredible!
Rain received across the forecast area as of 7:00 am December 13, 2015.
AND THE RAIN RETURNS TO DFW THIS WEEKEND [UPDATED WITH FORECAST AMOUNTS]
12/9/2015 Current satellite image of next storm system and path.
After a good reprieve from the excessive rainfall over the Thanksgiving Holidays, rain will return to North Texas this weekend. Rain chances will be highest on Saturday evening into Saturday night. The greatest threat for flash flooding will be along and east of the I-35 corridor where the heaviest rains fell last time. Grounds are still saturated from the last event, and coupled with the dormant vegetation, flash flooding will be a real concern. Instability with this system will be small with high shear, thus a rogue strong to severe storm cannot be ruled out.
A warm air advection pattern will continue through Saturday as southwest flow aloft prevails across the area out ahead of the storm system. This will advect moisture and ridiculously warm temperatures into our area. In fact, they will be downright hot for December. Highs on Friday may flirt with the record high at DFW which is 80°F set in 1938 and 1996. This will be highly dependent on cloud cover and moisture, thus the dfwweather.org forecast has officially kept highs just shy of the record. Overnight lows will be well above the normal high for early December Friday night (in the low to mid 60s) which is about 59°F. These temperatures are nearly 30 degrees above normal for this time of year. A Pacific cold front will push across the area Saturday night and this will be the main focus for shower and thunderstorm development. Some lingering rain showers behind the front may be possible on Sunday, especially if the slower ECMWF scenario pans out. Otherwise, temperatures will return to more seasonable levels behind the front with lows in the 40s and highs in the 50s.
It is too early to forecast rain amounts with the weekend system, but early indications are that amounts will generally be around an inch or less. It must be stressed, we are not expecting anywhere close to the amounts received over Thanksgiving.
We will be watching another storm system taking shape for next week that may bring even more rain to the area.
DFW Weather forecasted rain amounts through Sunday 12/13/2015.
NOVEMBER 2015 THE WETTEST NOVEMBER IN DFW HISTORY
Please check out the informative article Meteorologist Chris Robbins wrote over at iWeatherNet on the incredible rains we have received throughout 2015, including the fact that November came in as the wettest November in DFW history. Lots of great climatological data and analysis presented here:
IT’S OFFICIAL – DFW RECORDS ITS WETTEST YEAR OF RECORD
Out of 117 years of weather records, dating back to September of 1898, DFW records its wettest year on record officially today. With 55.30 inches of rain (as of 8am on Friday, November 27, 2015) this shatters the old record of 53.54 inches set in 1991 with the month of December left to go.
3 TO 5 INCHES OF RAIN EXPECTED BY SUNDAY AT DFW MAKING FOR THE WETTEST YEAR ON RECORD
A very wet holiday weekend is in store for much of the area. In fact, we are expecting 3 to 5 inches of rain across the area by Sunday. If this forecast verifies, this will make 2015 the wettest year on record at DFW. Currently, DFW is the 3rd wettest year on record with 50.75 inches of rain officially recorded. Only 1991 (53.54 inches) and 1932 (51.03 inches) are wetter. Thus, DFW only needs to pick up 2.80 inches of rain to break the record. We should out do that by Sunday with December left to go!
A large upper-low will move down from the Pacific northwest and carve out a deep trough over the western CONUS. This upper-low will become cut-off from the mean flow and slowly migrate eastward over the holiday weekend. At the same time, the deep trough will allow cold, Canadian/Arctic air to spill southward. This cold airmass will be very shallow in nature and move southward via cold air damming processes along the lee of the Rockies into Texas against southwest flow aloft. The coldest air will become entrenched across West Texas where temperatures will plummet below freezing setting up for a period of icy weather this weekend. Strong southwest flow aloft will moderate the cold air as it moves into our area. Thus, temperatures are expected to stay above freezing leading to a cold rain event at DFW. The heaviest rains will occur ahead and along a strong cold front expected to plunge through the area Friday morning. PWATs (precipitable water) are expected to climb as high as 1.75 inches during this event, which is in the 99th percentile for November. In addition, additional moisture will be advected over Texas from the remnants of tropical cyclone Sandra in the Pacific basin. All this points to a heavy rain event across the area. We are not expecting severe weather or wintry precipitation with this event, at this time.
Moisture and warm air advection should intensify today and tonight and become strong enough for areas of drizzle or light rain this evening into tomorrow. An increase in clouds and temperatures through Thanksgiving Day will be possible as this process intensifies out ahead of a strong cold front barreling southward. Precipitation chances increase later on Thanksgiving Day as lift begins to encroach on the area as the cold front moves southward. Rain showers, heavy at times, and few claps of thunder will be possible out ahead of, along, and behind the front as it moves through the area. Additional rainfall will be possible on Saturday through Sunday as the dynamics arrive from the remnants of tropical cyclone Sandra. By Sunday, we should pick up 3 to 5 inches of rain across the area. The upper-low should be moving out east across the Plains pushing the trough out of the area ending all rain from west to east on Sunday/Sunday night.
DFW HAS ITS FIRST FREEZE OF THE 2015-2016 SEASON
Yesterday, officially, DFW Airport records its first freeze of the 2015-2016 season. The temperature reached 30°F for yesterday’s low. This effectively ends the growing season for the area.
POTENTIAL FIRST FREEZE/FROST THIS WEEKEND [UPDATED]
UPDATE: The latest data continues to deepen the cold air behind early Saturday morning’s strong cold front (as discussed below). The airmass behind this front is going to be continental Canadian with H85 0°C line now projected to reach as far south as the I-20 corridor. This should promote widespread light freezing conditions across the northern half of the forecast area by Sunday morning. As a result, temperatures have been lowered Saturday into Monday. Temperatures may actually stay in the 40s for much of the day on Saturday with blustery north winds up to 35 mph and struggle to reach 50°F on Sunday. Clear skies and lighter winds will promote excellent radiational cooling potential Sunday morning with lows north of I-20 around the freezing mark, including DFW Airport. The colder spots may dip into the upper 20s. This is a good time to start winterizing your homes and taking precautions for sensitive vegetation. This cold snap will likely end the growing season for much of the area. There may be periods of light rain or drizzle on Saturday morning behind the front, but with the Gulf remaining shut off, precipitation looks rather meager at best and amounts will certainly be light.
The long range models continue to waffle back-and-fourth in the extended. There still seems to be signs of the possibility of an Arctic air intrusion around or just after the holidays . . .
High pressure will build in behind the departing low pressure and Pacific cold front today. The pressure gradient will tighten today from the building anti-cyclone and departing low pressure causing west southwest winds to gust to around 30 mph this afternoon, making for a windy day. The winds should decouple after sunset and allow temperatures to fall into the 40s everywhere overnight. Winds should stay up just enough to prohibit fog formation. Temperatures should remain seasonable through the end of the week with lows in the 40s and highs in the upper 60s to around 70°F, which is somewhat typical for this time of year (maybe a little warm on highs).
A stronger cold front is expected to arrive Saturday. Gulf moisture looks to remain cutoff from this front, so precipitation looks minimal. However, a very chilly airmass will advect in behind this front with H85 temps approaching 0°C. This will allow temperatures to plummet into the 30s area wide by Sunday and Monday mornings with highs only in the 50s. This will likely set the stage for the first frost of the season for the DFW Metroplex. Most likely, the cooler spots outside the urban heat island may even experience a light freeze. The average first freeze for DFW is November 22nd.
There are signs, and the ECMWF has been hinting at this for several runs, that the Arctic may open up just in time for the Thanksgiving holidays. The EPO (Eastern Pacific Oscillation) is projected to turn negative which is an indication of troughing across the central/eastern CONUS. The ECMWF continues to build an Arctic airmass in British Columbia and Northwest Territories seeding it from cross polar flow from Siberia. Then, spills this southward into the Plains and eastward over the holiday weekend or just after. The GFS has also shown some signs of this in the past several runs, however, the latest 0z run does not show this at all. This could be a very interesting thing to watch over the coming days . . .
OUR NEXT STORM SYSTEM APPROACHES
DFW is bracing itself for another round of rain, some of which could become heavy, especially very early Tuesday morning.
For Today (Saturday), a disturbance in the mid-levels of the atmosphere will be approaching from the southwest. This disturbance is already responsible for some convection upstream in the Trans-Pecos region. As it moves toward North Texas, it will help saturate the mid-levels of the atmosphere. However, it will be encountering increasingly drier air across our region, especially at the surface where dewpoints will largely remain below 50°F. As a result, think that any precipitation that forms will largely fall in the form of virga, rain that evaporates before reaching the ground. This will play havoc on high temperatures today. I think DFW will have a chance to warm into the 60s as the effects of the disturbance may not arrive in time to offset diurnal warming. However, the further southwest one goes, temperatures may be affected and some areas may fail to get out of the 50s today. The official forecast will call for occasional sprinkles today across DFW, maybe increasing to light rain tonight as the lower levels saturate. Rain amounts in general should stay at or less than 1/10 of an inch.
There should be a reprieve in any precipitation early Sunday morning as we await the dynamics from the approaching trough and strong upper-air disturbance. Rain should gradually increase from west to east Sunday as the system approaches. By Monday afternoon shear and instability increases and there could be a stronger storm or two. PWATs will also increase substantially by Monday night, as a squall line begins to take shape along a dryline/Pacific cold front racing fast across Texas. Some strong to possibly severe storms will be possible with this system, the main threats being from heavy rain due to higher PWATs, straight line winds, and possibly a spin-up or two. The squall line is not expected to reach the Metroplex to around daybreak Tuesday morning, thus the morning commute could be a wet one. The dryline/Pacific cold front pushes through Tuesday morning, thus I expect all of the storms to be east of DFW by 8:00 am ending all precipitation chances. The pressure gradient will tighten between the building anti-cyclone behind the front and departing low pressure system making for another windy day on Tuesday. Winds could gust in the 30 to 40 mph range. Seasonable weather will ensue the remainder of the week. Though I will stress nothing out of the ordinary by any standards, so expect temperatures to remain at or above normal for November. Early indications are that we could pick up 1 to 2 inches of rain by Tuesday.
Another cold front and system will bring the next chance at showers and thunderstorms by next weekend.
FORECAST UPDATE: STORM THREAT DIMINISHES – DRYLINE THROUGH MUCH OF THE METROPLEX
Today’s thunderstorm chances are rapidly diminishing as storms march eastward along with the dryline and cold front close behind. Strong, westerly, downsloping winds are increasing behind the dryline as the low pressure system deepens as it marches eastward across the central Plains. These strong downsloping winds will help temperatures soar to near record levels today. The record high temperature for today at DFW is 85°F set in 1911. Forecast highs were raised a bit after temperatures soared to the forecasted high of 83°F from this morning’s issuance. Winds will gust to near 35 mph behind the dryline making for a quite windy afternoon. Our winds will switch to the northwest this evening where they should decouple a bit after sunset. The much drier air will allow temperatures to cool efficiently this evening with overnight lows expected in the 40s area wide. We should be much cooler tomorrow with highs only reaching the mid to upper 60s.
We are still watching a southern stream system that could affect our weather as early as Saturday night with more chances of showers and thunderstorms, especially on Sunday and Monday. An even stronger system may be on tap for later next week.