Nat

iona

l Oce

anic

and

Atm

osph

eric

Adm

inis

tratio

nN

OAA

- ht

tps:

//ww

w.no

aa.g

ovN

OAA

Edu

catio

n Po

rtal -

http

s://w

ww.

noaa

.gov

/edu

catio

n

Nat

iona

l Wea

ther

Ser

vice

NW

S Ed

ucat

ion

- http

s://w

ww.

wea

ther

.gov

/ow

lieJe

tStre

am -

An O

nlin

e Sc

hool

for W

eath

er -

http

s://w

ww.

wea

ther

.gov

/jets

tream

NO

AA

Wea

ther

wis

e

War

m fr

ont

War

mer

air

repl

acin

g co

ol (o

r col

d) a

ir

Col

d fro

ntC

old

(or c

oole

r)ai

r rep

laci

ng

war

mer

air

Dry

line

Boun

dary

div

idin

gdr

y de

sert

air

from

moi

st

gulf

air

HHi

gh p

ress

ure

Loca

tion

of

high

est s

urfa

ceai

r pre

ssur

e

Stat

iona

ry fr

ont

Non

-mov

ing

boun

dary

divi

ding

war

m

air f

rom

coo

ler a

ir

Surfa

ce w

ind

Jet

stre

am

LLo

w p

ress

ure

Loca

tion

of

low

est s

urfa

ce

air p

ress

ure

idin

gai

r

HHi

ghpr

essu

reLo

catio

n of

hi

ghes

tsur

face

Surfa

ce w

ind

Jet

LLo

wpr

essu

reLo

catio

n of

lo

wes

tsur

face

HH

LHHHH

LLLLLHH

L

Jet s

tre

am

Equa

tor

Pola

r jet

str

eam Su

btro

pica

l je

t str

eam

Trop

ical

air

Tem

pera

teai

r

Pola

r air

Stro

ng w

inds

from

the

high

-pre

ssur

e sy

stem

car

ry c

olde

r, dr

ier a

ir in

to th

e da

rk b

lue

area

. As

the

cold

fron

t pa

sses

, pre

cipi

tatio

n en

ds a

nd s

kies

cle

ar fa

irly

rapi

dly.

Poss

ible

impa

cts

The

diffe

renc

e in

air

pres

sure

bet

wee

n tw

o po

ints

det

erm

ines

win

d sp

eed

and

dire

ctio

n. L

arge

pre

ssur

e di

ffere

nces

cau

se v

ery

stro

ng w

inds

. The

y ar

e m

ore

likel

y to

occ

ur in

win

ter a

nd c

an le

ad to

bliz

zard

con

ditio

ns

and

dang

erou

s w

ind

chills

. In

mou

ntai

nous

are

as, l

ight

ning

from

thun

ders

torm

s w

ith li

ttle

or n

o ra

infa

ll ca

n ig

nite

wild

fires

. The

se fi

res

may

spr

ead

rapi

dly

whe

n dr

iven

by

stro

ng w

inds

ass

ocia

ted

with

the

thun

ders

torm

.

Wea

ther

saf

ety

Rem

embe

r: Ic

e an

d Sn

ow, T

ake

It Sl

ow! b

oth

on a

nd o

ff th

e ro

ad. W

hile

driv

ing,

slo

w d

own

to re

duce

the

chan

ce o

f an

acci

dent

on

slip

pery

road

s. D

on’t

over

exer

t you

rsel

f whe

n sh

ovel

ing.

Avo

id p

rolo

nged

exp

osur

e to

col

d te

mpe

ratu

res,

whi

ch c

an c

ause

fros

tbite

and

/or h

ypot

herm

ia. P

repa

re fo

r and

be

awar

e of

pot

entia

l fire

ha

zard

s du

ring

dry

perio

ds.

Nor

th o

f the

col

d fr

ont

In th

e lig

ht b

lue

area

, the

air

tend

s to

be

cool

and

dry

. Clo

ser t

o th

e w

arm

fron

t, m

oist

ure

incr

ease

s. A

s a

resu

lt, c

loud

s th

icke

n,

whi

ch c

an le

ad to

rain

or s

now.

Poss

ible

impa

cts

War

m fr

onts

nea

r are

as o

f low

-pre

ssur

e ca

n br

ing

heav

y ra

in,

snow

, or s

leet

. Rai

n ca

n le

ad to

floo

ding

, whi

le s

now

and

sle

et

may

resu

lt in

a v

arie

ty o

f haz

ards

incl

udin

g sl

ick

road

s an

d po

wer

out

ages

.

Wea

ther

saf

ety

Nev

er d

rive

into

floo

ded

road

way

s or

aro

und

a ba

rrica

de. T

urn

Aro

und

Don

’t D

row

n! K

now

the

risks

of f

lood

s an

d pl

an y

our

evac

uatio

n ro

ute.

Hav

e ex

tra fo

od a

nd w

ater

in c

ase

you

lose

po

wer

or a

re tr

appe

d in

you

r hom

e. D

urin

g w

inte

r wea

ther

, driv

e sl

owly

or n

ot a

t all.

Nor

th o

f the

war

m fr

ont

War

m, m

oist

air

from

the

Gul

f of M

exic

o an

d At

lant

ic O

cean

mov

es in

to th

e gr

een

area

, in

crea

sing

tem

pera

ture

s an

d hu

mid

ity. S

how

ers

and

thun

ders

torm

s ca

n de

velo

p al

ong

and

in

adva

nce

of a

col

d fro

nt o

r dry

line

.

Poss

ible

impa

cts

War

m, m

oist

air

can

be fo

rced

upw

ards

as

it re

ache

s an

app

roac

hing

col

d fro

nt a

nd/o

r dry

line

. Th

is c

an c

ause

sev

ere

thun

ders

torm

s, fl

oodi

ng,

and

torn

adoe

s.

Wea

ther

saf

ety

Alw

ays

be W

eath

er-R

eady

— fo

reca

sts

can

prov

ide

seve

ral d

ays

adva

nce

notic

e of

sto

rms.

C

heck

them

regu

larly

. Be

prep

ared

and

W

hen

Thun

der R

oars

, Go

Indo

ors

to s

tay

safe

fro

m li

ghtn

ing.

Kno

w y

our s

afe

plac

e at

hom

e an

d w

ork.

Sou

th o

f the

war

m fr

ont

Sout

h of

the

fron

ts a

nd

wes

t of t

he d

ry li

neIn

the

oran

ge a

rea,

wea

ther

is g

ener

ally

dry

an

d m

ild. A

ppro

achi

ng fr

onts

can

lead

to h

igh

altit

ude

thun

ders

torm

s ov

er m

ount

ain

peak

s,

resu

lting

in s

trong

win

ds a

t the

sur

face

. Ove

r tim

e th

e ef

fect

s of

the

front

s w

ill di

min

ish.

To le

arn

mor

e ab

out t

he c

hara

cter

istic

s of

fron

ts,

expl

ore

the

rest

of t

he m

ap.

Poss

ible

impa

cts

Stro

ng s

urfa

ce w

inds

can

lead

to d

ust s

torm

s an

d w

ildfir

es. I

n So

uthe

rn C

alifo

rnia

, the

war

m,

dry

Sant

a An

a w

inds

blo

w to

war

ds th

e co

ast

from

the

high

des

ert a

reas

. Sea

sona

l hea

vy

rain

, eve

n fro

m d

ista

nt th

unde

rsto

rms,

can

lead

to

flas

h flo

ods

and

debr

is fl

ows

in ty

pica

lly v

ery

dry

area

s.

Wea

ther

saf

ety

Be a

lert

for d

ust s

torm

s, w

hich

can

com

e w

ith

little

war

ning

— P

ull A

side

, Sta

y A

live.

Pul

l far

of

f the

road

and

turn

all

car l

ight

s of

f. Fo

llow

ev

acua

tion

orde

rs d

urin

g fir

es. M

onito

r fo

reca

sts

for f

lash

floo

ds, w

hich

can

be

a ris

k m

any

mile

s fro

m a

sto

rm, e

spec

ially

in d

ry

valle

ys a

nd c

anyo

ns. D

on’t

be c

augh

t off

guar

d;

be p

repa

red

to m

ove

to h

ighe

r gro

und.

Expl

ore

mor

e w

eath

er p

heno

men

a at

ww

w.w

eath

er.g

ov/je

tstr

eam

Dra

win

g C

oncl

usio

ns •

Toas

ty W

ind

A Pr

essi

ng E

ngag

emen

t • G

oing

with

the

Flow

Sugg

este

d le

sson

s:

he w

eath

er w

e ex

perie

nce

ever

y da

y on

the

grou

nd is

a re

sult

of w

hat i

s ha

ppen

ing

far a

bove

our

hea

ds. U

p th

ere,

the

air i

s al

way

s m

ovin

g as

hea

t ene

rgy

is re

dist

ribut

ed a

cros

s th

e Ea

rth.

Met

eoro

logi

sts

stud

y ai

r mov

emen

t to

mak

e w

eath

er fo

reca

sts.

The

Sun

heat

s th

e Ea

rth, w

hich

then

hea

ts th

e ai

r in

the

atm

osph

ere.

Bec

ause

the

Sun

hits

the

equa

tor

mos

t dire

ctly,

the

air a

t the

equ

ator

rece

ives

mor

e he

at e

nerg

y th

an th

e ai

r clo

ser t

o th

e po

les.

Thi

s w

arm

air r

ises

bec

ause

it is

less

den

se th

an c

ool a

ir.

Whe

n th

e w

arm

air

reac

hes

the

uppe

r atm

osph

ere,

it c

an n

o lo

nger

rise

and

is fo

rced

tow

ard

the

pole

s.

As th

e ai

r coo

ls, i

t bec

omes

den

ser a

nd fa

lls b

ack

tow

ard

Earth

. Hig

h-pr

essu

re a

reas

form

whe

re c

oole

r

air i

s fa

lling

tow

ards

the

Earth

. Low

-pre

ssur

e ar

eas

form

whe

re w

arm

air

is ri

sing

. Air

circ

ulat

es fr

om

area

s of

hig

h pr

essu

re to

are

as o

f low

pre

ssur

e.

The

way

the

air m

oves

affe

cts

the

wea

ther

. Bet

wee

n th

e la

rge

area

s of

circ

ulat

ing

air,

jet s

trea

ms

form

.

Jet s

tream

s ar

e tu

be-li

ke p

aths

of s

trong

win

d m

ovin

g fro

m W

est t

o Ea

st a

roun

d th

e gl

obe.

The

pos

ition

and

stre

ngth

of j

et s

tream

s va

ry fr

om N

orth

to S

outh

, as

wel

l as

verti

cally

thro

ugho

ut th

e at

mos

pher

e.

The

loca

tion

of th

e je

t stre

ams

and

thei

r sea

sona

l mov

emen

t driv

e m

ajor

wea

ther

pat

tern

s ar

ound

the

wor

ld. I

n th

e U

nite

d St

ates

, col

d sn

aps

happ

en w

hen

the

pola

r jet

stre

am d

ips

sout

h. H

eat w

aves

can

occu

r whe

n th

e po

lar j

et s

tream

is v

ery

far n

orth

, allo

win

g fo

r war

m s

ub-tr

opic

al a

ir to

mov

e no

rth.

TBe

wea

ther

wis

e w

here

ver y

ou a

reTh

is m

ap s

how

s a

sim

plifi

ed fo

reca

st fo

r a s

ingl

e, h

ypot

hetic

al d

ay.

The

loca

tions

of t

he lo

w- a

nd h

igh-

pres

sure

sys

tem

s, je

t stre

am,

and

front

s sh

ape

the

wea

ther

that

a g

iven

regi

on m

ay e

xper

ienc

e.

Ther

e ca

n be

haz

ardo

us w

eath

er a

nyw

here

, at a

ny ti

me.

Beg

in

each

day

kno

win

g th

e w

eath

er fo

reca

st. I

f sev

ere

or e

xtre

me

wea

ther

is a

pos

sibi

lity,

per

iodi

cally

che

ck fo

r for

ecas

t upd

ates

. Be

pre

pare

d w

ith a

saf

ety

plan

. Hav

e a

“go-

kit”

with

impo

rtant

pr

oper

ty a

nd d

ocum

ents

read

y in

cas

e of

em

erge

ncy.

Hav

e at

leas

t a

thre

e-da

y su

pply

of f

ood

and

wat

er. L

earn

the

spec

ific

reco

mm

enda

tions

for r

egio

nal a

nd s

easo

nal w

eath

er h

azar

ds.

Lear

n m

ore

abou

t sea

sona

l saf

ety

at

http

s://w

ww.

wea

ther

.gov

/saf

etyc

ampa

ign.

C M Y CM MY

CY CMY

K

clou

dcha

rt_b

ack_

0829

19.a

i 1

8/

29/2

019

10:

57:1

4 A

Mcl

oudc

hart

_bac

k_08

2919

.ai

1

8/29

/201

9 1

0:57

:14

AM