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Texas/New Mexico/Louisiana/Mexico Obs And Discussion Thread Part 8


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NaOnJ5t.png

Somewhat cold winter for the East so far against 1981-2010, but S. TX is the current winner by anomalies. My outlook was against 1951-2010 mean highs, which are somewhat colder, so I think a lot of areas in the NE will actually w/in 1F against 1951-2010 highs for Dec-Jan. Had the Dakotas warm. Misses are the dryness in the Midwest and the heat in the West so far. I think against 1951-2010, the departures look something like this -

sLsNZBf.png

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On ‎1‎/‎30‎/‎2018 at 12:42 PM, aggiegeog said:

Umm, the most extreme 12Z GEFS member is showing lows on the 12th way below 0 (-20s in NE TX) with even some sub 0 highs. Lets hope we can toss out that possibility, but mean lows around 20 for days 10-16 is still crazy. Thursday morning is the only morning in the 16 day run with a mean low over 39. Wish there was more precip showing up, but that's life with persistent cold NW flow.

In all of weather records kept for North Texas area, the above scenario as has never occurred, so that was an easy disregard. Even during the severe Arctic outbreak of 1899 (coldest on record for this area), it wasn't that cold.

Nearly all of today's guidance unanimously is backing off on any Arctic air intrusions over the next couple of weeks, despite the -EPO and MJO phases, the abundance of cold air in Canada, and the highly amplified flow H5 pattern. Our best chances to see Arctic air intrusions are this Sunday 2/4 and again around 2/10. I'm not sure I totally buy off on this yet (especially for the 2/10 period), but it is sure looking like most of the cold air will be kept well north and east of Texas this go around. The operational models have not handled any of our cold air intrusions this winter well at all, and it could possibly change.

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18 hours ago, DFWWeather said:

In all of weather records kept for North Texas area, the above scenario as has never occurred, so that was an easy disregard. Even during the severe Arctic outbreak of 1899 (coldest on record for this area), it wasn't that cold.

Nearly all of today's guidance unanimously is backing off on any Arctic air intrusions over the next couple of weeks, despite the -EPO and MJO phases, the abundance of cold air in Canada, and the highly amplified flow H5 pattern. Our best chances to see Arctic air intrusions are this Sunday 2/4 and again around 2/10. I'm not sure I totally buy off on this yet (especially for the 2/10 period), but it is sure looking like most of the cold air will be kept well north and east of Texas this go around. The operational models have not handled any of our cold air intrusions this winter well at all, and it could possibly change.

Mid-month is looking very interesting with possible SSW resulting in a split PV and with SOI values crashing we could see the return of precip. I am not convinced of any solution right now, though I seriously doubt we see a torch of any kind. I am thinking we will see warmer lows and cooler highs vs what we saw in Jan as well as at least near average precip with potential for above average precip.

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Looking back at the Dec-Jan in the US since 1930 after a major hurricane hit Texas, would say 1980-81 is the closest. That year was a hot winter here, then it was wet in March.

Dec-Jan 1932, 1941, 1988, 1961, 1967 are all too cold in the West, off in the East too after a major hurricane hit Texas. 1957/1933/1999 are generally too warm everywhere after a major hurricane hits TX. 1942/1970 have other issues. 1983 is too cold everywhere. That leaves 1980-81, which is like an over-amplified version of this year. The 1980-81 Dec-Jan period had a warm Northern plains, warm West, cold East Coast, cold S. TX, cold South. That's the correct pattern.

It doesn't work at all for SSTs in the tropics, but 1980 (x3), 1983 (x2), 1999 (x1), 2002 (x2), 2014 (x1), 2016 (x1) produces the right kind of look for Dec-Jan nationally.

A look that is correct for SSTs and Dec-Jan would be 1944 (x1), 1977 (x1), 1980 (x2), 1983 (x3), 1999 (x1), 2002 (x3), 2005 (x4), 2010 (x2). Not many areas of the US more than 3F below 1951-2010 average for high temperatures. The blend of the two maps would be around an ~85% match nationally I think.

sFI5MHC.png

 

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Looking back at last year, we did pretty well for snow once the MJO reached the phase 2/3 transition around 2/28. For the high amplitude portion of the ongoing MJO wave, the cycles have been +49 to +55 days for phases 3,4,5,6,7 repeating, with a tendency toward the longer part of the cycle lately. Last year the MJO wave got to phase 2 on 1/21 and then 2/20 (+30 days), and then entered phase 3 on 1/26 before returning 2/28 (+33 days).

Given the +55 days cycle lately, the MJO should reach phase 8 around February 14th, sooner if the Euro is wrong about the slight retrogression towards phase 6 for a day or two. Phase one is then around Feb 22nd. Phase one is our strongest wet phase in February.

We entered phase three with current wave on 11/26 and then 1/14, so unless the wave dies or increases massively, its probably week one or week two of March.

Phase 3 Entrance: Nov 26/Jan 14 (+49)
Phase 4 Entrance: Nov 29/Jan 17 (+49)
Phase 5 Entrance: Dec 1 /Jan 22 (+52)
Phase 6 Entrance: Dec 5 /Jan 27 (+53)
Phase 7 Entrance: Dec 8 /Feb 1  (+55)
Phase 8 Entrance: Dec 20/ Feb 14 (+/-2 days?)  Euro has 2/15 but its been underestimating the MJO amplitude for the last week.

Real question at this point is when the wave dies. If it returns to the warm phases coherently in late March, the East will roast again.

 

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Based on frequency of very high SOI values in February, and the already-in crash for Feb 1-5 (-20.3 !!), odds of the SOI crashing negative this month are up to 66% or so. For the SOI to reach 0 for February given the SOI to date, you need the SOI to be +4.4 or higher the rest of the month, which isn't super common.

So, a crash of 9 or more from January is favored 2:1 right now. Its starting to look like we enter a somewhat stormy period, which makes sense. SOI crashes in February favor storminess at up to 0.7 correlations in the SW - although not sure if NOAA is using r-squared or just r.

DVUDNU8UQAA2QIf.jpg:large

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Icing likely tomorrow for the NW half of N TX and it is possible for all of N TX. E TX is looking at a chilly but stormy evening and night tomorrow with showers all day tomorrow.

A pretty solid upper air pattern for winter weather is setting up for the weekend so attention turns to that after tomorrow. Looks like we are in for a chilly and wet Feb around hereso winter mischief is def on the table this month.

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Freezing drizzle through tonight for the NW half of N TX, may try to push into Tarrant Co. Tomorrow morning we will have to watch for another round of freezing drizzle, mainly south of I-20, if temps drop below freezing tonight in those areas. This weekend and beyond look active but models are a jumbled mess right now.

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3 hours ago, aggiegeog said:

Freezing drizzle through tonight for the NW half of N TX, may try to push into Tarrant Co. Tomorrow morning we will have to watch for another round of freezing drizzle, mainly south of I-20, if temps drop below freezing tonight in those areas. This weekend and beyond look active but models are a jumbled mess right now.

Lovely.... That'll make my trip to work tomorrow extra fun

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Next Sunday and maybe into Monday could be wintery here in Texas. GFS starting to really dig the trough on Sunday on the 18Z though it shears it out before it reaches us so no wintery precip this run. Get that digging a bit deeper and hold it together longer and things turn very interesting around here.

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DVk8ML1UQAgrQf1.jpg

This is mostly from the subtropical jet if it verifies, so would be rain in most areas. But...its a start. Would be snow in the mountains of the North. I think the window for precipitation will remain open into March for us, before shutting abruptly again in April, but whether its February or March that is super wet remains to be seen. I looked for ABQ specifically the other day, the SOI drops in February are actually correlated more to temperatures than precipitation, so the crash may be a better pattern for the statewide precipitation than locally. Low SOI readings have correlations to February / March precipitation approaching 0.7 over a 60-year period in the SW...so I kind of believe it at this point. The Euro solution is only seven days out. The January SST configuration looks like some wet March years here, and what I expect for February is kind of a blend of 1968, 1975, 1981, 1985 at this point. There is no January since 1981 with a January as cold as 2018 in Nino 1.2, so I'm kind of relying on some older years. Worth noting that Jan 1968 & 1981 were both after major-hurricane landfalls in Texas.

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updated AFD from FTW, WWA WILL NEED to be expanded to include Metroplex if not NE Counties this afternoon IMHO: 

Quote

Area Forecast Discussion...UPDATED
National Weather Service Fort Worth TX
1042 AM CST Sat Feb 10 2018


.UPDATE...
The arctic airmass associated with this morning`s cold front has
made it through all but the southeastern-most counties late this
morning. Due to the shallow nature of the airmass, guidance has
had difficulty keeping up with the post-frontal temperature drop.
The leading edge of the freezing temperatures has already reached
a Bonham-Fort Worth-Comanche line and will continue to drop
southward this afternoon and evening.

Meanwhile, occasional light drizzle will switch over to freezing
drizzle as temperatures fall below 32. Precipitation is very light
and we do not expect any accumulations this afternoon. However, a
few slick spots on elevated surfaces and bridges can not be ruled
out, particularly for areas along and north of the I-20 corridor.

An upper level disturbance is still slated to move overhead late
tonight through Sunday morning. This is when we could see some
accumulations significant enough to produce travel delays due to
ice on both bridges and roads. The Winter Weather Advisory which
is in effect for tonight through Sunday morning across areas
southwest of the DFW Metroplex will likely need to be expanded
northeastward across the Metroplex, and possibly all the way to
the northeast counties based on the recent model guidance. This
expansion will be done with the afternoon forecast package when we
have gotten a good look at the suite of midday model guidance.


30

&&

 

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