This is going to be one nasty day of weather in the Boston area. The NWS has now upped the rain chance to 90 percent and it will be at 100 percent when you wake up tomorrow morning (ONE ADVANTAGE OF THIS -- LESS OF A HOMEFIELD ADVANTAGE)
Here is the latest precip map from HPC. As you can see, .5 to .75 inches of precip is schedule to fall in just a 6-hour period. I think this is conservative as does the NWS office in Boston which is calling for as much as 2 inches of rain.
Thunderstorms are a more significant threat Saturday than originally expected. Here is an excerpt from the Boston office's discussion. Some of this will be mumbo jumbo, but if you read the bold section, you'll ge the point.
A SECOND LOW LEVEL JET MOVES OVERHEAD WITH 30 TO AT TIMES 35 KNOTS A
COUPLE OF THOUSAND FEET OVERHEAD. AS WE MOVE INTO THE WARM SECTOR THE
AIRMASS WILL ALSO DESTABILIZE WITH LI VALUES ZERO TO -2 FROM MID
MORNING THROUGH THE AFTERNOON. THIS INSTABILITY COMBINED WITH THE
DYNAMIC LIFT WILL MEAN FAVORABLE CONDITIONS FOR SCATTERED
THUNDERSTORMS. PRECIPITABLE WATER VALUES OF 1.5 TO 1.75 POINT TO
POTENTIAL FOR HEAVY DOWNPOURS FROM ANY CONVECTION.
It also appears that wind could be a factor. It will be breezy Saturday with 10-15 mph winds, which will be higher in and around the thunderstorms.
Bottom line: It's going to be wet as hell and windy with a threat of thunderstorms. Ball security will be at a premium as will points.
The NWS precip chances continue to climb -- now 80 percent on Saturday. It is looking more and more like a very rainy game.
Here is HPC's precip map for the period from roughly 2 p.m. until 8 p.m.
Temps still expected to be mild -- upper 60s to low 70s.
Not much else to say, rain appears to be pretty much a certainty at this point -- the only question is "how much."
TUESDAY NIGHT UPDATE
As expected, the NWS has raised the rain chance from 30 percent on Saturday to a "likely" 60 percent. Even that percentage may go up. Below is the forecast discussion by the mets in the Boston NWS office regarding the upcoming rain event:
TIMING THIS FAR OUT IS NOT CERTAIN BUT MODELS ARE TARGETING THE PERIOD FROM SAT THROUGH
EARLY SUN. GFS/GGEM/ECMWF ALL INDICATE HEAVY QPF WITH POTENTIAL FOR 2-4" RAINFALL SOMEWHERE IN SNE. LOCATION UNCERTAIN. WE RAISED POPS TO LIKELY FROM LATE FRI NIGHT THROUGH EARLY SUN.
If you really want to get depressed, check out this forecasted precip map for the 48 hour period ranging from Friday AM until Saturday AM.
Fortunately, the news isn't all bad. It is looking increasingly like Boston will be in the warm sector of this storm, so high temps have been raised into the low 70s on Saturday.
Ugly looking weather pattern for New England into the weekend -- more like late fall than early October.
Still a long ways to go until Saturday, but if current model trends hold, FSU should see chilly, rainy and perhaps windy conditions Saturday in Mass.
Here are three forecast maps for the latest run of the computer model GFS.
First, at about dawn Saturday morning.
Then, early Saturday afternoon.
And finally, near dusk Saturday night.
See what I mean by ugly.
A big upper level low over the Great Lakes will spin late week and into the weekend. A cold front will drape down north/South through the Tenn. Valley to the Gulf Coast with a warm front running E/W from the G. Lakes through NY and just off the New England coast.
That spells wet and a tad chilly weather -- temps in the 50s, to near 60.
Right now the NWS in Boston is calling for a 30 percent chance of rain Saturday -- look for that to go up.