December Weather Discussion. Will We See Rain?

[redneckweather]

And there ya go. It looks like the Euro has finally come to its senses.

[TexasMetBlake]

The 12z Euro shows a solution similar to the gfs with placement of the ridge and trough. The low on this run is more sheared out and brings the energy much further north. I suspect, assuming there are no drastic changes, that this will be the solution that plays out.

In lamens terms, it lays out like this:

Houston: Rain
Austin: Rain
Waco: Rain
Dallas: Mixing with snow in the northern burbs
OKC: Snow

[don]

Yep I would like to see one more run of the Euro, but the latest run doesn't look pretty for those wanting snow...

[wxman57]

The 12z Euro shows a solution similar to the gfs with placement of the ridge and trough. The low on this run is more sheared out and brings the energy much further north. I suspect, assuming there are no drastic changes, that this will be the solution that plays out.

Yeah, 12Z Euro is considerably different from earlier runs with much less cold air. GFS still shows nothing at all. Canadian has a sharp trof but with the upper low (and sfc low) well to our north in OK/AR and little to now post-frontal precip.

Still too early to be extremely confident on next week's weather, but I do think that the Euro was overdoing it with the cold and upper low.

[snowman65]

weather.com actually has us (Orange, Tx) with 60% rain/snow showers next Wed......lol...

[Kludge]

[wxman57]

Yes, the Euro has been going back and forth as far as any prediction of frozen precip, but not the other models. Canadian has held firm that the precip would end close to frontal passage (just rain ahead of the front). GFS has held firm in the frontal passage with little or no precip. But models are tending to converge toward the Canadian solution of a little more cold air than the GFS and less than the Euro, but with little or no post-frontal precip. Most likely, the Euro was too aggressive with the cold and precip for next Tue-Wed. Canadian is probably closer. GFS doesn't show enough of an upper-level feature, so its precip forecast is likely out to lunch.

[Baseballdude2915]

I dont hear the fat lady singing?

Would like to see a few consistent runs from the GFS/Euro/CMC before we call it a non-event.
With past events in mind, i would say 12z Friday will be the day where we will have a general idea of what will happen.

For what it's worth:

[wxman57]

I dont hear the fat lady singing?

Would like to see a few consistent runs from the GFS/Euro/CMC before we call it a non-event.
With past events in mind, i would say 12z Friday will be the day where we will have a general idea of what will happen.

For what it's worth:
http://image.weather.com/images/maps/fo ... 40x297.jpg

Those are automated maps generated with whatever the latest model run they're using. Don't assume the mets there at TWC drew the map by hand after a careful analysis of all data. Model consensus is starting to grow concerning our weather next Tue-Wed. Trend is away from anything significant. It's possible the trend could still shift the other way. We should have a good idea what will more likely happen by around Friday or Saturday.

[TexasMetBlake]

For what it's worth, the JMA model has snow all along the gulf coast! LOL. It should be noted that the JMA (Japanese Model) is the biggest dissappointment since the AMC Pacer. HAAHAHAHAHA

Doesn't the 'commercial channel' make their own forecasts anyway? They don't use NWS products do they?

[helloitsb]

So is it time to give up on this thing or could models start shifting again?

[wxman57]

For what it's worth, the JMA model has snow all along the gulf coast! LOL. It should be noted that the JMA (Japanese Model) is the biggest disappointment since the AMC Pacer. HAAHAHAHAHA

Doesn't the 'commercial channel' make their own forecasts anyway? They don't use NWS products do they?

TWC does say that they have a forecast program in-house that learns from past mistakes (for the city forecasts). But I believe that graphics such as the regional precip graphics are automated based on whatever model they're programmed to use. You can bet that they're not having a big meeting of all the mets there to go over the expected rain/snow line for next Wednesday.

Was the Pacer or the Gremlin (perfect name) AMC's worst car? They had so many bad cars.

[TexasMetBlake]

Hey, never give up until the event is over. It is mine and everybody else's fault for really hyping up ANOTHER snow event for our area. We live in Houston, TX. We should understand that it does snow here, but rarely and never before has it snowed three yeears in a row. HOWEVER, who predicted sleet for the Houston area this morning? Reason I'm asking is because it was reported in several areas including Spring.

[wxman57]

So is it time to give up on this thing or could models start shifting again?

I wouldn't give up on the idea. We cannot be confident what will happen 8 days out. But from what I'm seeing now I'm feeling a little more confident that we won't see anything frozen here - at least anything frozen and sticking to the ground. Sleet isn't that hard to get down here, as we had a few pellets survive all the way to the ground just north of Houston this morning.

[helloitsb]

Hey, never give up until the event is over. It is mine and everybody else's fault for really hyping up ANOTHER snow event for our area. We live in Houston, TX. We should understand that it does snow here, but rarely and never before has it snowed three yeears in a row. HOWEVER, who predicted sleet for the Houston area this morning? Reason I'm asking is because it was reported in several areas including Spring.

Yeah who knows maybe the Euro was having a bad day

all jokes aside maybe the 18z will show us something else I'm not sure where to see the canadian and I haven't seen the most recent Euro but I can tell from the posts it isn't on our side (our being the winter weather people)

[wxman57]

Yeah who knows maybe the Euro was having a bad day

all jokes aside maybe the 18z will show us something else I'm not sure where to see the canadian and I haven't seen the most recent Euro but I can tell from the posts it isn't on our side (our being the winter weather people)

There is no 18Z Canadian or European. The 00Z runs come out by about 11pm CST (GFS) and around 1:30am CST for the Canadian and Euro.

Here's a good site to see the latest Euro, Canadian and GFS:

12Z:
http://www.meteo.psu.edu/~gadomski/ECMW ... floop.html

00Z:
http://www.meteo.psu.edu/~gadomski/ECMW ... floop.html

Allan's models page is also a very good site:
http://raleighwx.americanwx.com/models.html

Twister has great snow depth forecast charts. Just choose the GFS, NAM or RUC model and the winter link on the left then the snow depth graphic. Click the green time boxes to look at the projected snow accumulations for any time in the future:
http://www.twisterdata.com/

[helloitsb]

Yeah who knows maybe the Euro was having a bad day

all jokes aside maybe the 18z will show us something else I'm not sure where to see the canadian and I haven't seen the most recent Euro but I can tell from the posts it isn't on our side (our being the winter weather people)

Here's a good site to see the latest Euro, Canadian and GFS:

12Z:
http://www.meteo.psu.edu/~gadomski/ECMW ... floop.html

00Z:
http://www.meteo.psu.edu/~gadomski/ECMW ... floop.html

There is no 18Z Canadian or European. The 00Z runs come out by about 11pm CST (GFS) and around 1:30am CST for the Canadian and Euro.

Allan's models page is also a very good site:
http://raleighwx.americanwx.com/models.html

Thanks!! And yeah I was talking about the 18z GFS

[TexasMetBlake]

DFW:

THE BIG QUESTION ABOUT A WINTER EVENT OVER NORTH TEXAS REMAINS ON
THE TABLE. ONCE AGAIN THE ECMWF HAS CHANGED CONSIDERABLY...WITH
THE 00Z RUN PRODUCING NEAR RECORD SNOWS OVER NORTH TEXAS
TUESDAY...AND THE NEW 12Z RUN GIVING US A DUSTING. THE OPERATIONAL
GFS TAKES THE SHORT WAVE ENERGY FARTHER NORTH...WITH ANY WINTER
PRECIP LIKELY REMAINING IN KANSAS/OKLAHOMA. THAT IS PRETTY MUCH
THE SOLUTION IT GAVE YESTERDAY...AND GIVES ME A MORE CONFIDENCE
IN THE GFS OVER THE ERRATIC ECMWF.

THE GFS ENSEMBLE SPAGHETTI PLOTS BEGIN TO DIVERGE QUICKLY AFTER
SATURDAY MORNING. THE MEMBERS AGREE THAT AN UPPER LOW WILL
DEVELOP OVER EASTERN PACIFIC FRIDAY...BUT THE TRACKS OF THE
SYSTEM ARE QUITE DIVERGENT AND ONLY TWO MEMBERS OF THE 12 WE SEE
IN OUR SOFTWARE FORECAST ANY SNOW OVER TEXAS. THIS IS LESS THAN 20
PERCENT OF THE MEMBERS SO THE CONSENSUS IS THAT NO SNOW IS EXPECTED.

IS WINTER WEATHER POSSIBLE NEXT WEEK--YES. IS IT PROBABLE--NOT
YET. WHAT REMAINS PROBABLE/EXPECTED IS A COOL DOWN...A MAJORITY OF
ENSEMBLE MEMBERS/THE OPERATIONAL GFS/AND THE ECMWF ALL FORECAST
COOLER WEATHER NEXT WEEK. THIS TREND IS IN OUR FORECAST...BUT IT
IS TOO EARLY TO SAY YES TO A WINTER EVENT.

[TexasMetBlake]

Houston:

BOTH ECMWF AND GFS
BRINGS A CLOSED UPPER LOW JUST OFF CALIFORNIA LATE SUNDAY. GFS
WEAKENS THIS DISTURBANCE CONSIDERABLY AS IT MOVES EAST ACROSS.
SURFACE HIGH PRESSURE WILL CONTINUE TO RIDGE ACROSS OUR REGION
EARLY NEXT WEEK BRINGING UNSEASONABLY COLD AIR. OUR CONFIDENCE NOT
STRONG AT ALL FOR EARLY NEXT WEEKS FORECAST WITH MODELS CHANGING
RUN TO RUN. FOR NOW WE SHALL CONTINUE WITH SLIGHT CHANCE POPS
DURING LAST FEW DAYS OF FORECAST PACKAGE AND STAY CLOSE TO GFS MOS
TEMPERATURES. 37

[srainhoutx]

HPC Final Update may shed some light on the thinking, for what it is worth...

...12Z MODEL UPDATES...

THE MOST NOTEWORTHY TREND IN THE 12Z OPERATIONAL AND ENS MODEL
GUIDANCE IS THE SLOWING IN THE UPPER TROF ADVANCING THRU THE
DESERT SW. THE TWO MOST PRONOUNCED MEMBERS OF THE PARTY WHO SHOWED
SUCH A TREND ARE THE 12Z ECMWF/UKMET. GIVEN THE EARLIER
CONSISTENCY IN THE PREVIOUS SEVERAL RUNS OF THE ECMWF...THIS
CHANGE IN POSITION WAS A BIT SURPRISING. HOWEVER...THE NEW
PLACEMENT OF THE TROF AXIS IS NOW SLOWER THAN THE GLOBAL ENS MEANS
WHICH ALSO PLACES A BIT OF DOUBT INTO THE MORE RECENT SOLNS. ON
THE OTHER HAND...THE 12Z GFS HAS BECOME A TOUCH MORE PROGRESSIVE
WHICH PLACES IT CLOSER TO THE 12Z MODEL CLUSTER. ACRS THE
EAST...WHILE THERE ARE STILL QUITE A BIT OF DIFFERENCES EVIDENT
WITHIN THE DEVELOPMENT AND SUSTENANCE OF THE UPR VORTEX ACRS THE
NE U.S...THE GENERAL LARGE-SCALE PATTERN IS STILL HELD INTACT.
OVERALL...THE EARLIER PREFERENCE WILL BE MAINTAINED FOR THE
UPDATED AFTERNOON PACKAGE. ALTHOUGH THERE WAS A TREND OUT WEST
WITH THE NEW GUIDANCE...THE FACT THE 12Z DETERMINISTIC MODELS DID
NOT MATCH WELL WITH THE ENS MEANS WILL ALLOW THE ORIGINAL
PREFERENCE TO BE KEPT AS IS.