October 2013 pattern and discussion

GaWx · September 30, 2013

Folks,

Discuss the October weather pattern here as we bridge from the still warm month of September to the usually cool November.

Met1985 · September 30, 2013

Looks like we could have some transient cool downs but the first half of October looks pretty boring and maybe above average for most.

Brick Tamland · September 30, 2013

Loving the warm fall days and cool nights. This weather is perfect. I know it'll get cooler eventually, but there is no doubt fall is the best season in NC.

FallsLake · October 1, 2013

Definitely starting October in a warm pattern. 0z GFS tries to cool us down after 10 days or so; but, the NAO looks to go positive in the long range. Not sure how much the NAO affect us here in the SE this time of year. But at the very least it looks like no push of very cold air is in the offering anytime soon.

http://www.cpc.ncep.noaa.gov/products/precip/CWlink/pna/new.nao_index_ensm.html

Marion_NC_WX · October 1, 2013

Looking very unsettled for late this week...big trough, possible cutoff + tropical influx...

FLweather · October 1, 2013

I wouldnt put much stock in the nao right now. Just the other day it was wanting to scream negative.

The models are having a tough time with the transient nature of the GOA low and the split flow across Canada. With the right timing could be nothing or just a couple s/ws could phase to cause a trough. Really this time next week all the models could be singing a different tune and will be singing a different tune.

Really between sunday-tuesday timeframe we could be pretty wet in the SE if that trough can capture what is in the caribbean now and how strong it is by the end of the week.

Definitely starting October in a warm pattern. 0z GFS tries to cool us down after 10 days or so; but, the NAO looks to go positive in the long range. Not sure how much the NAO affect us here in the SE this time of year. But at the very least it looks like no push of very cold air is in the offering anytime soon.

Marion_NC_WX · October 2, 2013

Tonight's GFS runs continue the trend of stronger and farther west with INVEST 97L...the 0z run has a solid tropical storm making landfall near or just west of Panama City late Saturday night.

Marion_NC_WX · October 2, 2013

A lot of the hurricane models have our system in the Yucatan coming northward and accelerating as we get into this weekend. The 6z GFS strayed away from the previous trend and went back to a weaker system...that has been a trend with the previous INVEST's this season, 12z run will be intriguing.

If the models are correct, the remains of what could be "Karen" may accelerate toward the Southern Appalachians by Sunday. Asheville Regional Airport needs just 3.1 inches of rain to break the all-time yearly record. Could that record break this weekend? We'll see...

Marion_NC_WX · October 2, 2013

12z brings back a compact and intensifying tropical cyclone hitting the Florida Panhandle early Sunday...

FLweather · October 2, 2013

Yeah it looks pretty wet possiblity up the 65-85 corridor come early next week.

The hurricane hunters suppose to be flying into this today. Outflow aloft has gotten better overnight and today so far. Maybe have a TD by later as well.

FallsLake · October 3, 2013

GFS has been wavering the last few days from a large trough to a flatter looking pattern in the long range. The latest 18z shows what would be a nice cool down for most of the east by day 10. If things work out as depicted, this could be the first frost/freeze threat for many interior areas.

http://mag.ncep.noaa.gov/data/gfs/18/gfs_namer_288_850_temp_ht.gif

FLweather · October 3, 2013

Well I thought we would have had a TD or even Karen yesterday. But it didn't happen.

But looking at satelitte it has gotten better organized overnight even though a little lop sided. The LP center looks like it has tighten up as well.

We need this thing to strengthen today and start getting pulled north to have any hopes of a decent rain up and down the east coast towards early week. If it doesn't strengthen then appears that any decent rain chance is out the window to LA,MS,AL,AR, TN into the OH valley. Which in the long term may influence the whole upper level pattern allowing more warmth than any cool potential over the next month or so.

Marion_NC_WX · October 3, 2013

Well I thought we would have had a TD or even Karen yesterday. But it didn't happen.

But looking at satelitte it has gotten better organized overnight even though a little lop sided. The LP center looks like it has tighten up as well.

We need this thing to strengthen today and start getting pulled north to have any hopes of a decent rain up and down the east coast towards early week. If it doesn't strengthen then appears that any decent rain chance is out the window to LA,MS,AL,AR, TN into the OH valley. Which in the long term may influence the whole upper level pattern allowing more warmth than any cool potential over the next month or so.

NHC just broke out a special statement...Karen has formed in the Southern GOM 60 mph, Hurricane Watches being posted for parts of the Northern Gulf Coast

DATA FROM AN AIR FORCE RESERVE HURRICANE HUNTER AIRCRAFT INDICATES

THAT THE AREA OF LOW PRESSURE LOCATED OVER THE SOUTHEASTERN GULF OF

MEXICO HAS BECOME A TROPICAL STORM AND IS PRODUCING WINDS OF UP TO

60 MPH IN THE EXTREME SOUTHEASTERN GULF OF MEXICO. A SPECIAL

ADVISORY WILL BE ISSUED WITHIN THE NEXT HOUR...AND HURRICANE AND

TROPICAL STORM WATCHES WILL BE ISSUED FOR PORTIONS OF THE NORTHERN

GULF COAST.

FLweather · October 3, 2013

NHC just broke out a special statement...Karen has formed in the Southern GOM 60 mph, Hurricane Watches being posted for parts of the Northern Gulf Coast

DATA FROM AN AIR FORCE RESERVE HURRICANE HUNTER AIRCRAFT INDICATES

THAT THE AREA OF LOW PRESSURE LOCATED OVER THE SOUTHEASTERN GULF OF

MEXICO HAS BECOME A TROPICAL STORM AND IS PRODUCING WINDS OF UP TO

60 MPH IN THE EXTREME SOUTHEASTERN GULF OF MEXICO. A SPECIAL

ADVISORY WILL BE ISSUED WITHIN THE NEXT HOUR...AND HURRICANE AND

TROPICAL STORM WATCHES WILL BE ISSUED FOR PORTIONS OF THE NORTHERN

GULF COAST.

Thats good news in a way for SE rain chances. Not good for the folks along the immediate gulf coast from Apalachicola Fl to Fort Walton Beach. Just hope its not too powerful and too destructive for those folks.

Met1985 · October 5, 2013

The latest model runs look better for getting more cold air in here for next week. Looks like the mountains have a pretty good shot at seeing some frost if winds can die down.

Met1985 · October 6, 2013

Well after the rain moves out Monday it looks like we are in for a perfect week of fall weather. Looks seasonable with cool to cold nights all week long.

NavarreDon · October 6, 2013

Looks like we are going to have a decent shot at a good rain even without TD Karen.

GSP overnight part 1

THINGS CHANGE TONIGHT AS A DEEP UPPER LOW MOVES SOUTH OF THE GREAT
LAKES WITH A TROF SOUTH OF IT ALMOST REACHING THE GULF COAST. STRONG
SHORT WAVES AHEAD OF THIS LOW MOVE INTO THE AREA OVERNIGHT. THIS
WILL PROVIDE QUITE A BIT OF QG FORCING. IN ADDITION...UPPER
DIVERGENCE INCREASES AS THE RIGHT ENTRANCE REGION OF THE UPPER JET
MOVES TOWARD THE AREA. AT THE SFC...THE DECAYING REMNANTS OF KAREN
REMAIN ALONG THE GULF COAST AS A COLD FRONT MOVES TO THE MIDDLE OF
THE CWFA BY DAYBREAK. WHILE THIS KEEPS TROPICAL MOISTURE SOUTH OF
THE AREA...SLY FLOW AHEAD OF THIS SYSTEM WILL WILL BRING IN PW
VALUES FROM 1.5 TO 2 INCHES. LAPSE RATES ARE RELATIVELY WEAK...BUT
STEEPER THAN PREV FCST GIVEN THE NOW NON-TROPICAL AIR MASS. THE NAM
HAS CAPE VALUES AS HIGH AS 1000 J/KG WHILE THE GFS IS CONSIDERABLY
LOWER. THE SREF SHOWS MEAN MUCAPE OF 500 J/KG REACHING THE NC/SC
BORDER. THEREFORE...THERE WILL BE SOME WEAK INSTABILITY. THE BEST
SHEAR AND HELICITY WILL BE ACROSS NC WITH MEAN SHEAR VALUES 30 TO 40
KTS AND 0-1KM HELICITY UP TO 150 M2/S2. WITH INSTABILITY AND SHEAR
NOT EXACTLY LINING UP AND THE UNFAVORABLE TIME OF DAY...SVR STORM
CHC IS LOW. HOWEVER...GIVEN THE FORCING AND THAT THERE WILL BE SOME
INSTABILITY AND SHEAR...WILL HAVE TO KEEP AN EYE OUT FOR QLCS TYPE
STORMS...ESPECIALLY WITH GUIDANCE SHOWING A WAVE FORMING ALONG THE
FRONT AND MOVING NEAR THE NC/SC BORDER. HEAVY RAIN WILL BE POSSIBLE
AS WELL EVEN WITHOUT THE TOPICAL CONNECTION. QPF UP TO 1.5 INCHES
MAY FALL ALONG AND NEAR THE BLUE RIDGE.

NavarreDon · October 6, 2013

GSP overnight part 2:

CONCERNS WITH THE FROPA CONTINUE TO BE FOR POTENTIAL HEAVY RAIN AND
TSTMS BRINGING DAMAGING WINDS. DYNAMICS OF THE FRONT REMAIN VERY
IMPRESSIVE THANKS TO THE STRONG CLOSED UPPER LOW PASSING JUST TO OUR
NORTH. BEST UPPER DIVERGENCE MAY INDEED OUTPACE THE BEST SFC
CONVERGENCE...BUT THE LOW TO MIDLEVEL WINDS WILL BE VERY STRONG NEAR
THE SFC FRONT WITH AT LEAST A FEW HUNDRED JOULES OF CAPE AVAILABLE
EVEN PRIOR TO ANY INCREASE CAUSED BY DIURNAL HEATING. 0-3KM SHEAR OF
30-40 KT SHOWN OVER MAINLY THE NRN HALF OF THE CWFA WITH 20-30 KT TO
THE SOUTH. 0-6KM SHEAR IS ALSO SIGNIFICANT WITH 40 KT OR MORE ACRS
THE NRN ZONES NEARER THE UPPER LOW. THESE VALUES SUGGEST A THREAT OF
DOWNBURST WINDS AND BRIEF TORNADOES. TIMING OF THE FRONT WILL BRING
IT THRU THE MTNS/FOOTHILLS EARLY IN THE DAY...AND THE PIEDMONT DURING
PEAK HEATING. ANOTHER DIFFERENCE OVER THE PIEDMONT IS THAT MORE
CURVATURE IS NOTED IN THE LOWEST KM OR SO OF FCST HODOGRAPHS WHICH
WILL ENHANCE LLVL HELICITY AND TORNADO THREAT.

DESPITE KAREN/S APPARENT DEMISE...TROPICAL MOISTURE EVIDENCED BY PWAT
VALUES NEAR 2 STD DEV ABOVE CLIMO WILL ALLOW VERY HIGH RAINFALL
RATES. THUS I CHOSE TO GO NEAR HIGH END OF QPF GUIDANCE. RECENT DRY
CONDITIONS AND THE RELATIVELY QUICK FROPA MAY LIMIT THE FLOOD THREAT
THOUGH THE MOIST AIRMASS AND STRENGTH OF THE FRONT WILL CERTAINLY
WARRANT MONITORING HYDRO THRU THE EVENT.

ON A FINAL NOTE...MUCH COOLER TEMPS WILL BE NOTED TUE/WED
MORNING...ESPECIALLY TUE IN THE IMMEDIATE WAKE OF THE FRONT. NAM/CMC
INDICATE SOME LOWS IN THE MID-UPPER 30S POSSIBLE IN SOME MTN VALLEYS
TUE MORNING. THESE APPEAR TO BE OUTLIERS AT THIS TIME...BUT CONSENSUS
SUPPORTS MTN LOWS IN THE LOWER-MID 40S BOTH MORNINGS. BY WED MORNING
THE PIEDMONT WILL DROP INTO THE LOWER 50S.

The last paragraph is for 85!

Met1985 · October 6, 2013

ON A FINAL NOTE...MUCH COOLER TEMPS WILL BE NOTED TUE/WED

MORNING...ESPECIALLY TUE IN THE IMMEDIATE WAKE OF THE FRONT. NAM/CMC

INDICATE SOME LOWS IN THE MID-UPPER 30S POSSIBLE IN SOME MTN VALLEYS

TUE MORNING. THESE APPEAR TO BE OUTLIERS AT THIS TIME...BUT CONSENSUS

SUPPORTS MTN LOWS IN THE LOWER-MID 40S BOTH MORNINGS. BY WED MORNING

THE PIEDMONT WILL DROP INTO THE LOWER 50S.

The last paragraph is for 85!

Thanks Don!! Hey I'm going all in and saying the majority of the mountains say 2500 feet plus sees lows in the thirties and at 3500 feet plus May see frost this week.

NavarreDon · October 6, 2013

Thanks Don!! Hey I'm going all in and saying the majority of the mountains say 2500 feet plus sees lows in the thirties and at 3500 feet plus May see frost this week.

Somebody is riding your bus!

RaysWeather.Com ‏@raysweather 10m

Deeper mountain valleys in the High Country could experience some patchy frost next week.....first of the season in NC.

FallsLake · October 6, 2013

It looks like most will see a nice cool down starting Monday night. A lot of non mountain regions may see their first 60s high temps with sunny skies by mid week. I love this type of weather!

Looking at the GFS we may be looking at the first frost potential by day 10 or so. This time of year it takes a specific pattern setup to get that frost -- dew points at least in the mid-upper 30s, clear skies, and calm air. Day 10 (or so) we might get a cool high pressure to pass right over head and that may be our ticket. But that's day 10 and the next model run may not show this.

Marion_NC_WX · October 6, 2013

The GFS has been at odds this entire week on how to handle the current storm system that's coming across the Central and Eastern parts of the US...

Last night's runs wanted to sweep the trough through here quickly tomorrow to set up a nice and cool airmass across the Southeast for most of this week.

With that said...the new run of the GFS has flopped back to the idea of lingering a general cyclonic flow across the Southeast through Wednesday. Looking at the synoptics...the surface flow may turn due north by Tuesday but the 925mb flow is pretty stout from the east-northeast. From there the 500mb and 850mb flow is easterly. Some of this is in association with the remnant energy from Tropical Storm Karen, the GFS just does not want to sweep the airmass out to sea.

For North and South Carolina, while the temps may be lower next week, the moisture content from just off the surface up to 700 mb will be elevated so one has to wonder if the lower temps may end up coming with some cloud cover.

Met1985 · October 6, 2013

The GFS has been at odds this entire week on how to handle the current storm system that's coming across the Central and Eastern parts of the US...

Last night's runs wanted to sweep the trough through here quickly tomorrow to set up a nice and cool airmass across the Southeast for most of this week.

With that said...the new run of the GFS has flopped back to the idea of lingering a general cyclonic flow across the Southeast through Wednesday. Looking at the synoptics...the surface flow may turn due north by Tuesday but the 925mb flow is pretty stout from the east-northeast. From there the 500mb and 850mb flow is easterly. Some of this is in association with the remnant energy from Tropical Storm Karen, the GFS just does not want to sweep the airmass out to sea.

For North and South Carolina, while the temps may be lower next week, the moisture content from just off the surface up to 700 mb will be elevated so one has to wonder if the lower temps may end up coming with some cloud cover.

Ya the GFS and the Euro have been having a tough go with this setup. Seems like we are getting down to the wire here and the models are still not certain on what is going to happen. One thing I am noticing is that along the front we are getting moisture streaming up from from the GOM. Going to be a lot of rainfall the next 24 to 36 hours across the SE.

Met1985 · October 6, 2013

Somebody is riding your bus!

RaysWeather.Com ‏@raysweather 10m

Deeper mountain valleys in the High Country could experience some patchy frost next week.....first of the season in NC.

Hey Don I like to think I know what I am talking about sometimes. This airmass coming in this next week is going to be gorgeous.

NCSNOW · October 7, 2013

Temps in the Triad could possibly be in the upper 40's on the way home from work Tuesday afternoon. Eitheir way you slice it big changes this week Cool/Damp/Cloudy NE Breeze after todays front. I'll take it, the heat last week to 10 days has me crying uncle, ready for summer to give in and be gone!

THE TEMPERATURES WILL ALSO BE COLDER. THE

MORE RAIN... THE COLDER THE TEMPERATURES WILL BE. INTERESTINGLY

ENOUGH... AN EARLY SEASON COLD AIR DAMMING EVENT SHOULD UNFOLD IF

THE MODELS HOLD STEADFAST... AS THE PARENT HIGH IS OF SUFFICIENT

STRENGTH AND PROMINENT LOCATION FOR CLASSICAL CAD. SOME OF THE

MODELS SUGGEST THAT THE DEW POINTS WILL FALL INTO THE MID TO UPPER

40S IN THE NW PIEDMONT TUESDAY. IF THE RAIN DEVELOPS/SPREADS THAT

FAR NW... ACTUAL TEMPERATURES SHOULD FALL DURING THE DAY AND MAY

VERY WELL FALL THROUGH THE 50S. THE MAIN FORECAST CHALLENGE APPEARS

TO BE HOW FAR NW THE RAIN WILL DEVELOP TUESDAY... AND THIS WILL HAVE

SIGNIFICANT IMPACTS ON TEMPERATURES AS WELL.

FallsLake · October 7, 2013

30 degree drop in highs coming for many in the next few days. It looks like a CAD is setting up and folks in the CAD regions may be turning on heat by Wednesday.

From RAH:

.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...

AS OF 200 AM MONDAY...

CHILLING NE BREEZE...OCCASIONAL RAIN...AND COLD AIR DAMMING EXPECTED

TUESDAY INTO A PART OF WEDNESDAY.

TRENDS CONTINUE TO INDICATED A WETTER AND CHILLY SCENARIO FOR

TUESDAY INTO EARLY WEDNESDAY. THE LATEST MODELS CONTINUE TO INDICATE

THE A STRONG UPPER LEVEL DISTURBANCE WILL LIFT NE... JUST OFF THE

COAST OF SC/NC THIS PERIOD. AT THE SAME TIME... THE COLD FRONT THAT

WILL BRING THE SEVERE THREAT TODAY IS FORECAST TO STALL JUST TO OUR

EAST AND SOUTH TUESDAY... AND STRONG HIGH PRESSURE (1030+ MB) WILL

BE SURGING SOUTHWARD... DOWN THE EASTERN SEABOARD FROM NEW ENGLAND

INTO THE CAROLINAS. AS THE UPPER LEVEL DISTURBANCE MOVES NE NEAR THE

COAST TUESDAY INTO EARLY WEDNESDAY... DEEP MOISTURE IS EXPECTED TO

BE PULLED BACK INLAND OVER SC/NC. THE STRENGTH AND LOCATION OF THE

MID/UPPER LEVEL DISTURBANCE CONTINUES IN QUESTION. THE LATEST

GFS/NAM ARE EVEN FARTHER NW THAN THE PREVIOUS RUN SUGGESTING MUCH OF

OUR REGION... EVEN THE TRIAD WOULD GET IN ON THE RAIN. IN ADDITION

TO THE CLOUDS AND RAIN... THE TEMPERATURES WILL ALSO BE COLDER. THE