PRELIMINARY WINTER FORECAST 2011-12

Posted by wxrisk | GENERAL,SEASONAL FORECASTS | Thursday 29 September 2011 10:35 pm

WILL  BE  PRESENTED   HERE….  for the  General  Public… for the 1st time 

  You DO have to  to  register for this   events.   IF     you have  a  Chesterfield County Public Library card that has a PIN   then you can register online at www.library.chesterfield.gov or   you can  Bon Air Library at 804-320-2461 .      If you do NOT   have a    Chesterfield Library   card     then call to reserev  your spot .
Seating is somewhat limited…

WHAT HAPPENED TO THE CAPE VERDE HURRICANE SEASON?

Posted by wxrisk | GENERAL,HURRICANE SEASON 2012 | Sunday 18 September 2011 8:27 pm

2030   SEPT  18

 
Well here  we are  are in the Middle September and suddenly the active Cape Verde season which was roaring from  the Middle of August   into   Labor Day ….has shut down.  There   has been a lot of talk and speculation about why   this change and what is going on… so I  thought to take some time this surly Sunday evening and make a analysis and post about this .
This image represents the current satellite images from the far eastern Atlantic and from the central and western Atlantic and Caribbean Basin as of Sunday afternoon.  There are a couple of weak features trying to get organized in the far tropical Atlantic…  But absolutely nothing of any significance over the Gulf of Mexico the entire Caribbean and the southwestern Atlantic.

      

It looks more like the middle or late October than it does the middle of September.   Lets take a look WHY. 

Probably the most overlooked aspect of detecting increases in hurricane activity across the  MDR  –the main development region of the tropical Atlantic–   has to do with the  200 MB   vertical velocity  progs    care of  CPC— the climate prediction center.      If you go back and look at my earlier posts from the  early portion of  the middle of August I correctly forecasted a significant increase in Cape verde   tropical wave activity that will continue for 25 to 30 days.     I did so because I used this particular product which a lot of forecasters for some reason do not seem to use. 

Moreover this is a really easy product to use and understand even for the casual weather hobbyists.    This image shows us the  200 MB  vertical velocities as of August 18.       The growing areas show regions of strong vertical upward  motion at the high levels of the atmosphere which support tropical wave development in the various tropical regions around the world.     This product can also be used during the cold weather seasons but I will get into that another time.      The point here is that if you look over Africa and the eastern portions of the tropical Atlantic you  will  see large areas of   GREEN      ( rising    or UPWARDS  atmospheric   motion)   and some areas of convection which we can see by the  BLUEe-ish   Blobs.   In fact if you notice carefully over the far eastern portions of the tropical north Atlantic there are two distinct blobs that moves off the southwest African Coast.  One of these features in fact ended up becoming hurricane IRENE. 

The hostile areas  –represented by the BROWN  squiggly lines are restricted to the Pacific Basin — and represent sinking or downward motion which of course restricts   and  supresses any thunderstorm development.

Over the next few weeks we can track the movement of the 200 MB   Veritcal   Velocities — NOTE   the BLACK line…     And the favorable GREEN  areas are rapidly being pushed back into Africa Europe and the Indian Ocean while the hostile BROWN  areas become increasingly stronger—- with more of the squiggly lines are showing up on August 25 and August 30.    By September 8  these large hostile or negative   Veritical   Velocities    ( SINKING  AIR)    now cover the entire Atlantic Basin except maybe for the western portions of the Gulf of Mexico.      And by September 17 nothing really has changed…. as   the entire western and Central Atlantic Basin is experiencing hostile conditions and sinking air as shown by the  BROWN  squiggly lines.

In addition if we look at the overall large scale or synoptic pattern will see that for over the past seven days or so there     has been a large   UPPER LEVEL LOW    over the entire eastern Atlantic  at 500 MB which is dominating that entire region.        This  feature is  also producing very hostile conditions for any sort of  tropical wave  activity coming off the southwest coast of Africa and try and organize as it crosses were passes south of the Cape Verde  islands.

              

Even more significant is the fact that the overall pattern between New York and North America ensures that this large upper low in the tropical Atlantic Ocean is not going anywhere.  It is essentially trapped  aned NOT  going anywhere.  

 This is   WHY  the  cape Verde   Hurricane   has shut  down…  the    dominace    of   SINKING   air  and the    trapped huge   Upper Level Low — ULL-     had   ended  the Cape  Verde  Hurricane  season   10-14  days early.

NATE… MARIA… THE RAINS and the cold front

Posted by wxrisk | GENERAL,HURRICANE SEASON 2012 | Thursday 8 September 2011 11:09 pm

2300  EDT  SEPT 9 

First let me apologize for not updating the web site with some new information over the past few days.  Given how busy it’s been a last two weeks and all the other non weather family issues which have to be dealt with I kind of needed a break for few days.  This is even more the case now that we have to deal with tropical storms Maria tropical storm Nate the remains of  KATIA and large areas of persistent torrential rainfall across portions of the northeast us in the last 36 hours.  And we may even be dealing with the first significant cold air shot of the early autumn season sometime around the middle the month.

This first image I am presenting to show you the official surface map as of Thursday morning. 

      As you can see hurricane KATIA is due east of the North Carolina Coast and is passing between Bermuda and North Carolina.  This is a classic   surface Map of a  “slot hurricane”   and verifies the forecast that I made with regard to this system back on August 30. Although hurricane KATIA is not going to hit the East Coast  and has now turned and is beginning her Re-curve out to sea…  the close proximity of this slot hurricane has indirectly contributed to the exceptionally heavy rainfall which has affected much of the northeast  US  and eastern portions of the Middle Atlantic states.

One of the reasons why the rains have been so heavy was that the  heavy thunderstorm clusters and bands of heavy showers which developed over eastern Virginia …eastern North Carolina and eastern Maryland continue to move due north into eastern Pennsylvania and central and Eastern New York State.     In addition the moisture feed was coming directly from the Gulf stream   eastern of Florida and almost from the tropics.  This  means  that  there was a lot of Precipitable  water and high water vapor content in the atmosphere over the eastern US.  And third all this excessively humid moisture laden air would produce extremely heavy rainfall as it moves over higher and higher terrain in northeastern Pennsylvania  ( the Poconos)   and central and eastern York State— the Adirondack  Mountains.
We can see this by taking a look at these images which are enlarged   to focus mostly on the eastern US.  The upper air pattern shows that the cause of the impact on the jet stream  from KATIA  as a  strong ridge developed over the northwest portions of the northern Atlantic— reaching into far southeastern New England.  At the same time with the two large areas of cool High pressure over the Midwest  have  driven a cold front pressing in and trying to reach the East coast.  In addition the deep trough in the jet stream over the eastern third of the nation combined with the close proximity of KATIA  off the coast has set up a pronounced and very strong flow of southerly winds from east of Florida   all away into New York State and Eastern New England.


NATE…  The global or large scale weather models have been all over the place with the early track of tropical storm NATE  in the far southern portions of the Gulf of Mexico  (an atrea  called the bay of Campeche) .  The GFS and the Canadian models have been trying to lift the system north the cause of the trough over the Midwest and eastern US.  The argument here would be the trough would act as a weakness in the pattern so Nate   W would get a chance to come north.  Normally that sort of forecast  would make sense but the problem is that the base the trough is at 32° N latitude all Nate is still below 20° N latitude.  That makes a gap of 12° latitude which is simply too far apart for  Midwest  trough like this to capture or pull   Nate northward.     The established rule shows that when the trough base gets thrown about 10°   of the tropical cyclone than it begins to affect the overall path.


Over the next two or three days and trough over the Midwest is gonna get progressively weaker and the ridge will build been across the deep south of the Gulf coast states which means that eventually need will have to turn to the west and move into the northern portions of old Mexico and not into southern U.S.
MARIA…  All day long she has looked very weak and has probably fallen below tropical storm status from time to time.  As I stated several times before the weakening of the tropical storm into a bear minimal system greatly enhances the chance that the system is going to stay due west for prolonged period of time.   Not surprisingly this trend has shows up in all of the hurricane models from earlier today.  This image shows  the  track from 18z   THURSDAY SEPT 7… and te next one  is from 0z  SEPT  8.  As you can see the models are in very strong agreement that a weak tropical storm Maria is going to swing through the Bahamas before it begins to get a chance to develop.  Whether not the system is going to come north into the middle antics states greatly depends upon whether not a strong cold front can arrive in time from the Midwest.

     
The  12z  European model clearly does not think so.  The model is very clear that as a tropical storm MARIA moves in  to the Bahamas a large and strong cold front with a impressively large cool air mass will drive into the East coast on the 15th of September  just as a tropical storm or hurricane Maria and  getting  pushed  harmlessly out to sea.     MY  view right now is to think that that is the probable solution.  There is a chance that tropical storm Maria might get very close to southeastern North Carolina before the cold front arrives.  If that were to happen this system could end in making a sharp right turn and be kicked out to sea quite rapidly because it looks like this cold front on the 15th of September means business

       

KATIA: It’s going to be CLOSE but odds Still favor “SLOT HURRICANE”

Posted by wxrisk | GENERAL,HURRICANE SEASON 2012 | Saturday 3 September 2011 7:30 pm

1915 EDT 3  SEPT

Omce again  the    BIG scale or  Global  Models  played  flipped  flop with MOST of them   early   Saurday  morning  showing KATIA a   more    East  or  “OTS”   …Out to sea  track…. while the   12z    Global  Models  bringing Katia  MUCH closer to the  East coast  …from NC  to  Cape Cod Mass.    And  on top of that  the  Hurircane Models  have been Just as  inconsistent with  SOME of them showing a more  rapid turn to the NNW  then N  then NNE  (out to sea)    but some Hurricane Models  show KATIA  heading  WNW and     THREATENING  the  NC coast.

THREATENING…  not hitting  the NC   or  east coast… just  looking more   Threatening.

Before  we  begin…  keep in mind some  RULES… or strong  guidelines.  FIRST   keep in mind that   in the  days before IRENE  hit   ALL of the Hurricane  models swung  WAAAAAAAAY  east.    This is  why so  many TV     mets…   why  TWC (  the weather  channel) and  why  NHC kept  insisting   Irene  was  NOT  going to  be a  big deal and she  was going to pass    over or  east of Hatteras.  However starting  about  3  days  before   IRENE  Saturday AUG 27   landfall…  the  Hurircane Models  finally got a  clue and shifted  well west.

 Long story made short… this sort of  north and East  bias in the   Hurricane Models is well know  by those who  dont  have   to  tow  the  NHC/ NWS   party line.   This bias  occurs because  ALL of  the Hurricane  Models are based off the GFS   model  grid.   Recall  the GFS   model  awful  performace with IRENE    in the 84 to 144 hours time  frame .    It is  NOT  a coincidence  that the GFS  was also    waaaaay to  east   with IRENE  in the   72  to 144  hour  time frame… and the   Hurricane  models  has the same sort  of bias.

 NEXT  once we get  within   72  hours of   POSSIBLE  Landfall with Katia the    GFS  and  Hurricance  Models  are MUCH better  and  DO  matter.

THIRD   RULE…   Hurricanes ONLY  hit the   East coast  when the  overall pattern    FORCES  the Hurricane  into the coast (IRENE… FLOYD…)  or   on the coast   then inland (ISABEL). 

 FOURTH Models  reflect the atmosphere … NOT  the other  way around.   In other words    IF Katia   hits  the  NC outerbansk  on say  SEPT 9  it  is because the   pattern  supports  that  NOT because the    Nogaps or  GFS  model  says   so.   REGARDLESS  of what   ANY  Model  says  if the pattern does   not support the  idea  of KATIA hitting   the   NC or somewhere  on the East coast… the Model  is probably  wrong.

The weakening of  KATIA   is  important ….  since weaker    Tropical  Cyclones are far more   likely to    track  W or WNW than   strong     Hurricanes.   Here is the 12z  SEPT 3   run of the GFS …. VALID for sept 9… and it is much further east    than any other  Global  or large scale  model.

Nere is the  12z   much improved  Nogaps  model… with a  much  further  West track for Katia…  clssic  SLOT  Hurricane   track.    ( the 0z SEPT 3  nogaps  actually   had  Katia  making  landfall in the northern Middle Atlantic)

   

12z CMC   / Canadian… again showing a clearly  much  west track  — clearly a   SLOT  HURRICANE ” track

 

12z SEPT  3  EUROPEAN MODEL … again  passing within 100-200 miles of   far eastern NC and se of Cape  Cod

 The  12z  vs the 18z Hurricane  Models …  note the  WEST shift

    

The 12z  SEPT  3  European  Model ensembles

 

KATIA… and LEE… and the EAST COAST LABOR DAY FORECAST

Posted by wxrisk | GENERAL,HURRICANE SEASON 2012 | Thursday 1 September 2011 9:57 pm

 2145  edt  SEPT 1  2011

 Hello  from WINTERGREEN  RESORT in the Shenandoah  mountains.   Need to get  sway  from the     lies  and  crap  spewing from  Dominion Power  about how  all these work crews are headed for Chester VA.  Day after day … the lying  gets to be a bit  much.    OK lets get to it.

 The early morning   THURSDAY Models  all clearly  showed KATIA  turning out to sea   and tracking   fair  close to  Bermuda  and NOT  being a threat to anyone.   The   early morning   models  did so    BECAUSE  they have   Katia   too far to the  N  so the  cold front and   trough in  Je stream  have to grab  Katia  and   take  her east.   And   the  developing  system in the   Gulf   that will  beome  Lee   was shown to be moving into  western and  southern TX and NOT  bringing   heavy / torrential  rains to the interior  SE  CONUS  and into EWVA   and VA.

Much has  changed –  EXACTLY  as I said they would in Yesterdays –AUG 31  update.   ALL the models on this Thursday  afternoon  has KATIA   tracking  due   West and  NOT getting  picked up  by  the  SEPT 5   East coast  trough that moves out into the  western Atlantic  ocean.    KATIA  is   STILL   a threat and still has to be  watched .

This is   important  because   this  allows   Katia to turn  WEST.    In fact  KATIA    all day  has moved due  West and NOT WNW ….and is still moving  WEST  right now.    In addition the  weakening   today    also favors  Katia    staying West  for a PROLONGED  period of time.     ( reasoning– weaker  Tropical   depreessions or   Storms   do not  build or extend  higher into the  atmosphere so  they  follow the  Low levels winds   where was     Hurricanes     Follow  Upper Levels  much more  so).  

 12z   THURSDAY SEPT 1  GFS  RUN…   again   has   KATIA  much  further North  than  ANY  other model… which is a strong sign  the Model’s cold  or poleward Bias with  Tropical cyclones  is   working.  The  GFS   has Katia   so far North that  the  SEPT 9-10   cold front  HAS  to  kick her east.  

   

The 12z    THURSDAY  SEPT  1  EURO  has KATIA  hundreds of  miles   to the  SW   and  she  turns  due west and  comes close  — within 200 miles  of   southeast   FL.     These maps  show  WHY…  essentially   IF   Katia is   that far south  at  SEPT 4   the  East coast  trough of  SEPT  5  will by pass  her  and Katia  turns  WEST.     This   increases  the threat of  KATIA   making a close  pass to the  se    or middle  Atlantic  coast.

 
 
 

    

BUT….odds still favor  OTS– Out to sea  track.   But  It could be close. 

The   18z  GFS    has    seen  reality and has  Katia    still missing the  East coast   but passing  within  150 miles of   Cape  Hatteras. 

  The   12z    SEPT 1    day 7.5  Canadian also   shows  Katia   coming    due   west   THEN   getting  picked  up  by a MASSIVE   east coast  trough  SEPT 8.

 The  12z NOGAPS  with its vastly improved  4DVAR  package    shows  this  WEST   track and also has   Katia  getting close to FL and the south east US coast.    BUT again  it also    has the  massive  East coast trough and  cold front SEPT  9 kicking   her   N  then NE…

         

=================================

1800  EDT   AUG 31  2011

God I am tired.   and NOT  happy  at all and very  stressed.  Let  get right to it.

 The 12z GFS Model  AUG  31 screws up the   development of   LIKELY   TC– tropical  Cyclone – in the Gulf of Mexico  over the long   holiday weekend.     The Model develops  this system — LIKELY   to be called  “LEE“    by  foming it  over the  central Gulf  then  moving it into  the   LA/ DELTA  region  by   SEPT 4.      NO other model  does this– as you will see.   BUT   this has  MAJOR  complications for the Forecast for   the  ENTIRE  EAST COAST.

     

The GFS  Model  still  brings in   pretty good   early Autumn Trough in the jet stream /  cold  front at the surface into the  Midwest the  East coast BY SEPT  4-5 .     That is Unchanged .  However because  the wretched  GFS  has LEE   or  LEE’s   remains over the Delta ….the  Model   pulls   LEE and  his  rains  Northeast  UP the front  and into    SC NC  VA   MD  DE PA NJ  NY    and eastern  New England   MONDAY  SEPT 5.

   

 Since so many  TV   weather folks and  TWC    kiss  the   GFS  ass   every   day… their  forecasts are LIKELY to be  quite  wet for Labor day along the East coast.     My  forecast is NOT  nearly  as   wet.  To be sure there may be  SOME showers  SEPT   5th  with the cold front passage   BUT nothing like the heavy rains the    12z   AUG 31  GFS  is showing. 

 But   beyond  that the   12z GFS Model  STALLS the   SEPT 5   cold front  over the     Appalachian Mountains   from  NE GA  to   western NC  western VA  WVA  western MD   western and central PA…. and  this right  is   deluge  by the Model  in the   6-10 day.

  

  My  view    ?    Bullshit…

 The     EUROPEAN  Model as well as the  Canadian  and British  model– the Ukmet  —ALL have LEE  over  far western Gulf   through n SEPT  6.   These models  either develop LEE into a   Hurricane  near  the TX coast OR  move  him inland BUT  the   key point here is that they do NOT bring  LEE  North  into the LA  Delta .    Since   Lee  on these models  is NJOT there… these Models have NO    heavy rains on the   East coast   SEPT 5. 

     

Got  it? 

 KATIA..  she is   cranking along Nicely as  you can see here.

  

A  quick Glance  at all the data seems to show a   recurve   out to sea track.    But    I am NOT  yet confident about that … Yet.    The Key   point  remains WHERE  will KATIA  be    SEPTM 4-5  as  she moves NJE  then N of  Puerto  Rico.

The 12z  european Model  and the  new 18z Hurricane Models shows KATIA turning back West     SEPT 5 -6-7  as the 1st cold front   misses  here and she   neats the    central Bahams.    The Euro show  the  2nd cold front.. a major trough  sweeping  through the Midwest and  East coast   SEPT  9-10  will  kick her   east.

        

18z HURRICANE   MODELS

So far so good.    BUT  there is a risk  that  the 2nd cold front  COULD  be  weaker or delayed.  IF  that happens  as Katia is   heading   West NW   she  could come  very close to the  NC eastern  coast.   I am NOT  forecasting that right now   But I am  NOT  ruling it out right now.    Sometimes  in science  we  just dont    things.  Rather  than BS you  I tell  you wnat I know    what I dont know  and when I will  know  some more.